drivers/spi/spi.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 // SPI init/core code
   3 //
   4 // Copyright (C) 2005 David Brownell
   5 // Copyright (C) 2008 Secret Lab Technologies Ltd.
   6
   7 #include <linux/acpi.h>
   8 #include <linux/cache.h>
   9 #include <linux/clk/clk-conf.h>
  10 #include <linux/delay.h>
  11 #include <linux/device.h>
  12 #include <linux/dmaengine.h>
  13 #include <linux/dma-mapping.h>
  14 #include <linux/export.h>
  15 #include <linux/gpio/consumer.h>
  16 #include <linux/highmem.h>
  17 #include <linux/idr.h>
  18 #include <linux/init.h>
  19 #include <linux/ioport.h>
  20 #include <linux/kernel.h>
  21 #include <linux/kthread.h>
  22 #include <linux/mod_devicetable.h>
  23 #include <linux/mutex.h>
  24 #include <linux/of_device.h>
  25 #include <linux/of_irq.h>
  26 #include <linux/percpu.h>
  27 #include <linux/platform_data/x86/apple.h>
  28 #include <linux/pm_domain.h>
  29 #include <linux/pm_runtime.h>
  30 #include <linux/property.h>
  31 #include <linux/ptp_clock_kernel.h>
  32 #include <linux/sched/rt.h>
  33 #include <linux/slab.h>
  34 #include <linux/spi/spi.h>
  35 #include <linux/spi/spi-mem.h>
  36 #include <uapi/linux/sched/types.h>
  37
  38 #define CREATE_TRACE_POINTS
  39 #include <trace/events/spi.h>
  40 EXPORT_TRACEPOINT_SYMBOL(spi_transfer_start);
  41 EXPORT_TRACEPOINT_SYMBOL(spi_transfer_stop);
  42
  43 #include "internals.h"
  44
  45 static DEFINE_IDR(spi_master_idr);
  46
  47 static void spidev_release(struct device *dev)
  48 {
  49         struct spi_device       *spi = to_spi_device(dev);
  50
  51         spi_controller_put(spi->controller);
  52         kfree(spi->driver_override);
  53         free_percpu(spi->pcpu_statistics);
  54         kfree(spi);
  55 }
  56
  57 static ssize_t
  58 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
  59 {
  60         const struct spi_device *spi = to_spi_device(dev);
  61         int len;
  62
  63         len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
  64         if (len != -ENODEV)
  65                 return len;
  66
  67         return sysfs_emit(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
  68 }
  69 static DEVICE_ATTR_RO(modalias);
  70
  71 static ssize_t driver_override_store(struct device *dev,
  72                                      struct device_attribute *a,
  73                                      const char *buf, size_t count)
  74 {
  75         struct spi_device *spi = to_spi_device(dev);
  76         int ret;
  77
  78         ret = driver_set_override(dev, &spi->driver_override, buf, count);
  79         if (ret)
  80                 return ret;
  81
  82         return count;
  83 }
  84
  85 static ssize_t driver_override_show(struct device *dev,
  86                                     struct device_attribute *a, char *buf)
  87 {
  88         const struct spi_device *spi = to_spi_device(dev);
  89         ssize_t len;
  90
  91         device_lock(dev);
  92         len = sysfs_emit(buf, "%s\n", spi->driver_override ? : "");
  93         device_unlock(dev);
  94         return len;
  95 }
  96 static DEVICE_ATTR_RW(driver_override);
  97
  98 static struct spi_statistics __percpu *spi_alloc_pcpu_stats(struct device *dev)
  99 {
 100         struct spi_statistics __percpu *pcpu_stats;
 101
 102         if (dev)
 103                 pcpu_stats = devm_alloc_percpu(dev, struct spi_statistics);
 104         else
 105                 pcpu_stats = alloc_percpu_gfp(struct spi_statistics, GFP_KERNEL);
 106
 107         if (pcpu_stats) {
 108                 int cpu;
 109
 110                 for_each_possible_cpu(cpu) {
 111                         struct spi_statistics *stat;
 112
 113                         stat = per_cpu_ptr(pcpu_stats, cpu);
 114                         u64_stats_init(&stat->syncp);
 115                 }
 116         }
 117         return pcpu_stats;
 118 }
 119
 120 static ssize_t spi_emit_pcpu_stats(struct spi_statistics __percpu *stat,
 121                                    char *buf, size_t offset)
 122 {
 123         u64 val = 0;
 124         int i;
 125
 126         for_each_possible_cpu(i) {
 127                 const struct spi_statistics *pcpu_stats;
 128                 u64_stats_t *field;
 129                 unsigned int start;
 130                 u64 inc;
 131
 132                 pcpu_stats = per_cpu_ptr(stat, i);
 133                 field = (void *)pcpu_stats + offset;
 134                 do {
 135                         start = u64_stats_fetch_begin(&pcpu_stats->syncp);
 136                         inc = u64_stats_read(field);
 137                 } while (u64_stats_fetch_retry(&pcpu_stats->syncp, start));
 138                 val += inc;
 139         }
 140         return sysfs_emit(buf, "%llu\n", val);
 141 }
 142
 143 #define SPI_STATISTICS_ATTRS(field, file)                               \
 144 static ssize_t spi_controller_##field##_show(struct device *dev,        \
 145                                              struct device_attribute *attr, \
 146                                              char *buf)                 \
 147 {                                                                       \
 148         struct spi_controller *ctlr = container_of(dev,                 \
 149                                          struct spi_controller, dev);   \
 150         return spi_statistics_##field##_show(ctlr->pcpu_statistics, buf); \
 151 }                                                                       \
 152 static struct device_attribute dev_attr_spi_controller_##field = {      \
 153         .attr = { .name = file, .mode = 0444 },                         \
 154         .show = spi_controller_##field##_show,                          \
 155 };                                                                      \
 156 static ssize_t spi_device_##field##_show(struct device *dev,            \
 157                                          struct device_attribute *attr, \
 158                                         char *buf)                      \
 159 {                                                                       \
 160         struct spi_device *spi = to_spi_device(dev);                    \
 161         return spi_statistics_##field##_show(spi->pcpu_statistics, buf); \
 162 }                                                                       \
 163 static struct device_attribute dev_attr_spi_device_##field = {          \
 164         .attr = { .name = file, .mode = 0444 },                         \
 165         .show = spi_device_##field##_show,                              \
 166 }
 167
 168 #define SPI_STATISTICS_SHOW_NAME(name, file, field)                     \
 169 static ssize_t spi_statistics_##name##_show(struct spi_statistics __percpu *stat, \
 170                                             char *buf)                  \
 171 {                                                                       \
 172         return spi_emit_pcpu_stats(stat, buf,                           \
 173                         offsetof(struct spi_statistics, field));        \
 174 }                                                                       \
 175 SPI_STATISTICS_ATTRS(name, file)
 176
 177 #define SPI_STATISTICS_SHOW(field)                                      \
 178         SPI_STATISTICS_SHOW_NAME(field, __stringify(field),             \
 179                                  field)
 180
 181 SPI_STATISTICS_SHOW(messages);
 182 SPI_STATISTICS_SHOW(transfers);
 183 SPI_STATISTICS_SHOW(errors);
 184 SPI_STATISTICS_SHOW(timedout);
 185
 186 SPI_STATISTICS_SHOW(spi_sync);
 187 SPI_STATISTICS_SHOW(spi_sync_immediate);
 188 SPI_STATISTICS_SHOW(spi_async);
 189
 190 SPI_STATISTICS_SHOW(bytes);
 191 SPI_STATISTICS_SHOW(bytes_rx);
 192 SPI_STATISTICS_SHOW(bytes_tx);
 193
 194 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number)              \
 195         SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index,           \
 196                                  "transfer_bytes_histo_" number,        \
 197                                  transfer_bytes_histo[index])
 198 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0,  "0-1");
 199 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1,  "2-3");
 200 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2,  "4-7");
 201 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3,  "8-15");
 202 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4,  "16-31");
 203 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5,  "32-63");
 204 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6,  "64-127");
 205 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7,  "128-255");
 206 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8,  "256-511");
 207 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9,  "512-1023");
 208 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
 209 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
 210 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
 211 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
 212 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
 213 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
 214 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
 215
 216 SPI_STATISTICS_SHOW(transfers_split_maxsize);
 217
 218 static struct attribute *spi_dev_attrs[] = {
 219         &dev_attr_modalias.attr,
 220         &dev_attr_driver_override.attr,
 221         NULL,
 222 };
 223
 224 static const struct attribute_group spi_dev_group = {
 225         .attrs  = spi_dev_attrs,
 226 };
 227
 228 static struct attribute *spi_device_statistics_attrs[] = {
 229         &dev_attr_spi_device_messages.attr,
 230         &dev_attr_spi_device_transfers.attr,
 231         &dev_attr_spi_device_errors.attr,
 232         &dev_attr_spi_device_timedout.attr,
 233         &dev_attr_spi_device_spi_sync.attr,
 234         &dev_attr_spi_device_spi_sync_immediate.attr,
 235         &dev_attr_spi_device_spi_async.attr,
 236         &dev_attr_spi_device_bytes.attr,
 237         &dev_attr_spi_device_bytes_rx.attr,
 238         &dev_attr_spi_device_bytes_tx.attr,
 239         &dev_attr_spi_device_transfer_bytes_histo0.attr,
 240         &dev_attr_spi_device_transfer_bytes_histo1.attr,
 241         &dev_attr_spi_device_transfer_bytes_histo2.attr,
 242         &dev_attr_spi_device_transfer_bytes_histo3.attr,
 243         &dev_attr_spi_device_transfer_bytes_histo4.attr,
 244         &dev_attr_spi_device_transfer_bytes_histo5.attr,
 245         &dev_attr_spi_device_transfer_bytes_histo6.attr,
 246         &dev_attr_spi_device_transfer_bytes_histo7.attr,
 247         &dev_attr_spi_device_transfer_bytes_histo8.attr,
 248         &dev_attr_spi_device_transfer_bytes_histo9.attr,
 249         &dev_attr_spi_device_transfer_bytes_histo10.attr,
 250         &dev_attr_spi_device_transfer_bytes_histo11.attr,
 251         &dev_attr_spi_device_transfer_bytes_histo12.attr,
 252         &dev_attr_spi_device_transfer_bytes_histo13.attr,
 253         &dev_attr_spi_device_transfer_bytes_histo14.attr,
 254         &dev_attr_spi_device_transfer_bytes_histo15.attr,
 255         &dev_attr_spi_device_transfer_bytes_histo16.attr,
 256         &dev_attr_spi_device_transfers_split_maxsize.attr,
 257         NULL,
 258 };
 259
 260 static const struct attribute_group spi_device_statistics_group = {
 261         .name  = "statistics",
 262         .attrs  = spi_device_statistics_attrs,
 263 };
 264
 265 static const struct attribute_group *spi_dev_groups[] = {
 266         &spi_dev_group,
 267         &spi_device_statistics_group,
 268         NULL,
 269 };
 270
 271 static struct attribute *spi_controller_statistics_attrs[] = {
 272         &dev_attr_spi_controller_messages.attr,
 273         &dev_attr_spi_controller_transfers.attr,
 274         &dev_attr_spi_controller_errors.attr,
 275         &dev_attr_spi_controller_timedout.attr,
 276         &dev_attr_spi_controller_spi_sync.attr,
 277         &dev_attr_spi_controller_spi_sync_immediate.attr,
 278         &dev_attr_spi_controller_spi_async.attr,
 279         &dev_attr_spi_controller_bytes.attr,
 280         &dev_attr_spi_controller_bytes_rx.attr,
 281         &dev_attr_spi_controller_bytes_tx.attr,
 282         &dev_attr_spi_controller_transfer_bytes_histo0.attr,
 283         &dev_attr_spi_controller_transfer_bytes_histo1.attr,
 284         &dev_attr_spi_controller_transfer_bytes_histo2.attr,
 285         &dev_attr_spi_controller_transfer_bytes_histo3.attr,
 286         &dev_attr_spi_controller_transfer_bytes_histo4.attr,
 287         &dev_attr_spi_controller_transfer_bytes_histo5.attr,
 288         &dev_attr_spi_controller_transfer_bytes_histo6.attr,
 289         &dev_attr_spi_controller_transfer_bytes_histo7.attr,
 290         &dev_attr_spi_controller_transfer_bytes_histo8.attr,
 291         &dev_attr_spi_controller_transfer_bytes_histo9.attr,
 292         &dev_attr_spi_controller_transfer_bytes_histo10.attr,
 293         &dev_attr_spi_controller_transfer_bytes_histo11.attr,
 294         &dev_attr_spi_controller_transfer_bytes_histo12.attr,
 295         &dev_attr_spi_controller_transfer_bytes_histo13.attr,
 296         &dev_attr_spi_controller_transfer_bytes_histo14.attr,
 297         &dev_attr_spi_controller_transfer_bytes_histo15.attr,
 298         &dev_attr_spi_controller_transfer_bytes_histo16.attr,
 299         &dev_attr_spi_controller_transfers_split_maxsize.attr,
 300         NULL,
 301 };
 302
 303 static const struct attribute_group spi_controller_statistics_group = {
 304         .name  = "statistics",
 305         .attrs  = spi_controller_statistics_attrs,
 306 };
 307
 308 static const struct attribute_group *spi_master_groups[] = {
 309         &spi_controller_statistics_group,
 310         NULL,
 311 };
 312
 313 static void spi_statistics_add_transfer_stats(struct spi_statistics __percpu *pcpu_stats,
 314                                               struct spi_transfer *xfer,
 315                                               struct spi_controller *ctlr)
 316 {
 317         int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
 318         struct spi_statistics *stats;
 319
 320         if (l2len < 0)
 321                 l2len = 0;
 322
 323         get_cpu();
 324         stats = this_cpu_ptr(pcpu_stats);
 325         u64_stats_update_begin(&stats->syncp);
 326
 327         u64_stats_inc(&stats->transfers);
 328         u64_stats_inc(&stats->transfer_bytes_histo[l2len]);
 329
 330         u64_stats_add(&stats->bytes, xfer->len);
 331         if ((xfer->tx_buf) &&
 332             (xfer->tx_buf != ctlr->dummy_tx))
 333                 u64_stats_add(&stats->bytes_tx, xfer->len);
 334         if ((xfer->rx_buf) &&
 335             (xfer->rx_buf != ctlr->dummy_rx))
 336                 u64_stats_add(&stats->bytes_rx, xfer->len);
 337
 338         u64_stats_update_end(&stats->syncp);
 339         put_cpu();
 340 }
 341
 342 /*
 343  * modalias support makes "modprobe $MODALIAS" new-style hotplug work,
 344  * and the sysfs version makes coldplug work too.
 345  */
 346 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id, const char *name)
 347 {
 348         while (id->name[0]) {
 349                 if (!strcmp(name, id->name))
 350                         return id;
 351                 id++;
 352         }
 353         return NULL;
 354 }
 355
 356 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
 357 {
 358         const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
 359
 360         return spi_match_id(sdrv->id_table, sdev->modalias);
 361 }
 362 EXPORT_SYMBOL_GPL(spi_get_device_id);
 363
 364 const void *spi_get_device_match_data(const struct spi_device *sdev)
 365 {
 366         const void *match;
 367
 368         match = device_get_match_data(&sdev->dev);
 369         if (match)
 370                 return match;
 371
 372         return (const void *)spi_get_device_id(sdev)->driver_data;
 373 }
 374 EXPORT_SYMBOL_GPL(spi_get_device_match_data);
 375
 376 static int spi_match_device(struct device *dev, struct device_driver *drv)
 377 {
 378         const struct spi_device *spi = to_spi_device(dev);
 379         const struct spi_driver *sdrv = to_spi_driver(drv);
 380
 381         /* Check override first, and if set, only use the named driver */
 382         if (spi->driver_override)
 383                 return strcmp(spi->driver_override, drv->name) == 0;
 384
 385         /* Attempt an OF style match */
 386         if (of_driver_match_device(dev, drv))
 387                 return 1;
 388
 389         /* Then try ACPI */
 390         if (acpi_driver_match_device(dev, drv))
 391                 return 1;
 392
 393         if (sdrv->id_table)
 394                 return !!spi_match_id(sdrv->id_table, spi->modalias);
 395
 396         return strcmp(spi->modalias, drv->name) == 0;
 397 }
 398
 399 static int spi_uevent(const struct device *dev, struct kobj_uevent_env *env)
 400 {
 401         const struct spi_device         *spi = to_spi_device(dev);
 402         int rc;
 403
 404         rc = acpi_device_uevent_modalias(dev, env);
 405         if (rc != -ENODEV)
 406                 return rc;
 407
 408         return add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
 409 }
 410
 411 static int spi_probe(struct device *dev)
 412 {
 413         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 414         struct spi_device               *spi = to_spi_device(dev);
 415         int ret;
 416
 417         ret = of_clk_set_defaults(dev->of_node, false);
 418         if (ret)
 419                 return ret;
 420
 421         if (dev->of_node) {
 422                 spi->irq = of_irq_get(dev->of_node, 0);
 423                 if (spi->irq == -EPROBE_DEFER)
 424                         return -EPROBE_DEFER;
 425                 if (spi->irq < 0)
 426                         spi->irq = 0;
 427         }
 428
 429         ret = dev_pm_domain_attach(dev, true);
 430         if (ret)
 431                 return ret;
 432
 433         if (sdrv->probe) {
 434                 ret = sdrv->probe(spi);
 435                 if (ret)
 436                         dev_pm_domain_detach(dev, true);
 437         }
 438
 439         return ret;
 440 }
 441
 442 static void spi_remove(struct device *dev)
 443 {
 444         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 445
 446         if (sdrv->remove)
 447                 sdrv->remove(to_spi_device(dev));
 448
 449         dev_pm_domain_detach(dev, true);
 450 }
 451
 452 static void spi_shutdown(struct device *dev)
 453 {
 454         if (dev->driver) {
 455                 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
 456
 457                 if (sdrv->shutdown)
 458                         sdrv->shutdown(to_spi_device(dev));
 459         }
 460 }
 461
 462 struct bus_type spi_bus_type = {
 463         .name           = "spi",
 464         .dev_groups     = spi_dev_groups,
 465         .match          = spi_match_device,
 466         .uevent         = spi_uevent,
 467         .probe          = spi_probe,
 468         .remove         = spi_remove,
 469         .shutdown       = spi_shutdown,
 470 };
 471 EXPORT_SYMBOL_GPL(spi_bus_type);
 472
 473 /**
 474  * __spi_register_driver - register a SPI driver
 475  * @owner: owner module of the driver to register
 476  * @sdrv: the driver to register
 477  * Context: can sleep
 478  *
 479  * Return: zero on success, else a negative error code.
 480  */
 481 int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
 482 {
 483         sdrv->driver.owner = owner;
 484         sdrv->driver.bus = &spi_bus_type;
 485
 486         /*
 487          * For Really Good Reasons we use spi: modaliases not of:
 488          * modaliases for DT so module autoloading won't work if we
 489          * don't have a spi_device_id as well as a compatible string.
 490          */
 491         if (sdrv->driver.of_match_table) {
 492                 const struct of_device_id *of_id;
 493
 494                 for (of_id = sdrv->driver.of_match_table; of_id->compatible[0];
 495                      of_id++) {
 496                         const char *of_name;
 497
 498                         /* Strip off any vendor prefix */
 499                         of_name = strnchr(of_id->compatible,
 500                                           sizeof(of_id->compatible), ',');
 501                         if (of_name)
 502                                 of_name++;
 503                         else
 504                                 of_name = of_id->compatible;
 505
 506                         if (sdrv->id_table) {
 507                                 const struct spi_device_id *spi_id;
 508
 509                                 spi_id = spi_match_id(sdrv->id_table, of_name);
 510                                 if (spi_id)
 511                                         continue;
 512                         } else {
 513                                 if (strcmp(sdrv->driver.name, of_name) == 0)
 514                                         continue;
 515                         }
 516
 517                         pr_warn("SPI driver %s has no spi_device_id for %s\n",
 518                                 sdrv->driver.name, of_id->compatible);
 519                 }
 520         }
 521
 522         return driver_register(&sdrv->driver);
 523 }
 524 EXPORT_SYMBOL_GPL(__spi_register_driver);
 525
 526 /*-------------------------------------------------------------------------*/
 527
 528 /*
 529  * SPI devices should normally not be created by SPI device drivers; that
 530  * would make them board-specific.  Similarly with SPI controller drivers.
 531  * Device registration normally goes into like arch/.../mach.../board-YYY.c
 532  * with other readonly (flashable) information about mainboard devices.
 533  */
 534
 535 struct boardinfo {
 536         struct list_head        list;
 537         struct spi_board_info   board_info;
 538 };
 539
 540 static LIST_HEAD(board_list);
 541 static LIST_HEAD(spi_controller_list);
 542
 543 /*
 544  * Used to protect add/del operation for board_info list and
 545  * spi_controller list, and their matching process also used
 546  * to protect object of type struct idr.
 547  */
 548 static DEFINE_MUTEX(board_lock);
 549
 550 /**
 551  * spi_alloc_device - Allocate a new SPI device
 552  * @ctlr: Controller to which device is connected
 553  * Context: can sleep
 554  *
 555  * Allows a driver to allocate and initialize a spi_device without
 556  * registering it immediately.  This allows a driver to directly
 557  * fill the spi_device with device parameters before calling
 558  * spi_add_device() on it.
 559  *
 560  * Caller is responsible to call spi_add_device() on the returned
 561  * spi_device structure to add it to the SPI controller.  If the caller
 562  * needs to discard the spi_device without adding it, then it should
 563  * call spi_dev_put() on it.
 564  *
 565  * Return: a pointer to the new device, or NULL.
 566  */
 567 struct spi_device *spi_alloc_device(struct spi_controller *ctlr)
 568 {
 569         struct spi_device       *spi;
 570
 571         if (!spi_controller_get(ctlr))
 572                 return NULL;
 573
 574         spi = kzalloc(sizeof(*spi), GFP_KERNEL);
 575         if (!spi) {
 576                 spi_controller_put(ctlr);
 577                 return NULL;
 578         }
 579
 580         spi->pcpu_statistics = spi_alloc_pcpu_stats(NULL);
 581         if (!spi->pcpu_statistics) {
 582                 kfree(spi);
 583                 spi_controller_put(ctlr);
 584                 return NULL;
 585         }
 586
 587         spi->master = spi->controller = ctlr;
 588         spi->dev.parent = &ctlr->dev;
 589         spi->dev.bus = &spi_bus_type;
 590         spi->dev.release = spidev_release;
 591         spi->mode = ctlr->buswidth_override_bits;
 592
 593         device_initialize(&spi->dev);
 594         return spi;
 595 }
 596 EXPORT_SYMBOL_GPL(spi_alloc_device);
 597
 598 static void spi_dev_set_name(struct spi_device *spi)
 599 {
 600         struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
 601
 602         if (adev) {
 603                 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
 604                 return;
 605         }
 606
 607         dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->controller->dev),
 608                      spi_get_chipselect(spi, 0));
 609 }
 610
 611 static int spi_dev_check(struct device *dev, void *data)
 612 {
 613         struct spi_device *spi = to_spi_device(dev);
 614         struct spi_device *new_spi = data;
 615         int idx, nw_idx;
 616         u8 cs, cs_nw;
 617
 618         if (spi->controller == new_spi->controller) {
 619                 for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) {
 620                         cs = spi_get_chipselect(spi, idx);
 621                         for (nw_idx = 0; nw_idx < SPI_CS_CNT_MAX; nw_idx++) {
 622                                 cs_nw = spi_get_chipselect(new_spi, nw_idx);
 623                                 if (cs != 0xFF && cs_nw != 0xFF && cs == cs_nw) {
 624                                         dev_err(dev, "chipselect %d already in use\n", cs_nw);
 625                                         return -EBUSY;
 626                                 }
 627                         }
 628                 }
 629         }
 630         return 0;
 631 }
 632
 633 static void spi_cleanup(struct spi_device *spi)
 634 {
 635         if (spi->controller->cleanup)
 636                 spi->controller->cleanup(spi);
 637 }
 638
 639 static int __spi_add_device(struct spi_device *spi)
 640 {
 641         struct spi_controller *ctlr = spi->controller;
 642         struct device *dev = ctlr->dev.parent;
 643         int status, idx, nw_idx;
 644         u8 cs, nw_cs;
 645
 646         for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) {
 647                 /* Chipselects are numbered 0..max; validate. */
 648                 cs = spi_get_chipselect(spi, idx);
 649                 if (cs != 0xFF && cs >= ctlr->num_chipselect) {
 650                         dev_err(dev, "cs%d >= max %d\n", spi_get_chipselect(spi, idx),
 651                                 ctlr->num_chipselect);
 652                         return -EINVAL;
 653                 }
 654         }
 655
 656         /*
 657          * Make sure that multiple logical CS doesn't map to the same physical CS.
 658          * For example, spi->chip_select[0] != spi->chip_select[1] and so on.
 659          */
 660         for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) {
 661                 cs = spi_get_chipselect(spi, idx);
 662                 for (nw_idx = idx + 1; nw_idx < SPI_CS_CNT_MAX; nw_idx++) {
 663                         nw_cs = spi_get_chipselect(spi, nw_idx);
 664                         if (cs != 0xFF && nw_cs != 0xFF && cs == nw_cs) {
 665                                 dev_err(dev, "chipselect %d already in use\n", nw_cs);
 666                                 return -EBUSY;
 667                         }
 668                 }
 669         }
 670
 671         /* Set the bus ID string */
 672         spi_dev_set_name(spi);
 673
 674         /*
 675          * We need to make sure there's no other device with this
 676          * chipselect **BEFORE** we call setup(), else we'll trash
 677          * its configuration.
 678          */
 679         status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
 680         if (status)
 681                 return status;
 682
 683         /* Controller may unregister concurrently */
 684         if (IS_ENABLED(CONFIG_SPI_DYNAMIC) &&
 685             !device_is_registered(&ctlr->dev)) {
 686                 return -ENODEV;
 687         }
 688
 689         if (ctlr->cs_gpiods) {
 690                 u8 cs;
 691
 692                 for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) {
 693                         cs = spi_get_chipselect(spi, idx);
 694                         if (cs != 0xFF)
 695                                 spi_set_csgpiod(spi, idx, ctlr->cs_gpiods[cs]);
 696                 }
 697         }
 698
 699         /*
 700          * Drivers may modify this initial i/o setup, but will
 701          * normally rely on the device being setup.  Devices
 702          * using SPI_CS_HIGH can't coexist well otherwise...
 703          */
 704         status = spi_setup(spi);
 705         if (status < 0) {
 706                 dev_err(dev, "can't setup %s, status %d\n",
 707                                 dev_name(&spi->dev), status);
 708                 return status;
 709         }
 710
 711         /* Device may be bound to an active driver when this returns */
 712         status = device_add(&spi->dev);
 713         if (status < 0) {
 714                 dev_err(dev, "can't add %s, status %d\n",
 715                                 dev_name(&spi->dev), status);
 716                 spi_cleanup(spi);
 717         } else {
 718                 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
 719         }
 720
 721         return status;
 722 }
 723
 724 /**
 725  * spi_add_device - Add spi_device allocated with spi_alloc_device
 726  * @spi: spi_device to register
 727  *
 728  * Companion function to spi_alloc_device.  Devices allocated with
 729  * spi_alloc_device can be added onto the SPI bus with this function.
 730  *
 731  * Return: 0 on success; negative errno on failure
 732  */
 733 int spi_add_device(struct spi_device *spi)
 734 {
 735         struct spi_controller *ctlr = spi->controller;
 736         int status;
 737
 738         /* Set the bus ID string */
 739         spi_dev_set_name(spi);
 740
 741         mutex_lock(&ctlr->add_lock);
 742         status = __spi_add_device(spi);
 743         mutex_unlock(&ctlr->add_lock);
 744         return status;
 745 }
 746 EXPORT_SYMBOL_GPL(spi_add_device);
 747
 748 /**
 749  * spi_new_device - instantiate one new SPI device
 750  * @ctlr: Controller to which device is connected
 751  * @chip: Describes the SPI device
 752  * Context: can sleep
 753  *
 754  * On typical mainboards, this is purely internal; and it's not needed
 755  * after board init creates the hard-wired devices.  Some development
 756  * platforms may not be able to use spi_register_board_info though, and
 757  * this is exported so that for example a USB or parport based adapter
 758  * driver could add devices (which it would learn about out-of-band).
 759  *
 760  * Return: the new device, or NULL.
 761  */
 762 struct spi_device *spi_new_device(struct spi_controller *ctlr,
 763                                   struct spi_board_info *chip)
 764 {
 765         struct spi_device       *proxy;
 766         int                     status;
 767         u8                      idx;
 768
 769         /*
 770          * NOTE:  caller did any chip->bus_num checks necessary.
 771          *
 772          * Also, unless we change the return value convention to use
 773          * error-or-pointer (not NULL-or-pointer), troubleshootability
 774          * suggests syslogged diagnostics are best here (ugh).
 775          */
 776
 777         proxy = spi_alloc_device(ctlr);
 778         if (!proxy)
 779                 return NULL;
 780
 781         WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
 782
 783         /*
 784          * Zero(0) is a valid physical CS value and can be located at any
 785          * logical CS in the spi->chip_select[]. If all the physical CS
 786          * are initialized to 0 then It would be difficult to differentiate
 787          * between a valid physical CS 0 & an unused logical CS whose physical
 788          * CS can be 0. As a solution to this issue initialize all the CS to 0xFF.
 789          * Now all the unused logical CS will have 0xFF physical CS value & can be
 790          * ignore while performing physical CS validity checks.
 791          */
 792         for (idx = 0; idx < SPI_CS_CNT_MAX; idx++)
 793                 spi_set_chipselect(proxy, idx, 0xFF);
 794
 795         spi_set_chipselect(proxy, 0, chip->chip_select);
 796         proxy->max_speed_hz = chip->max_speed_hz;
 797         proxy->mode = chip->mode;
 798         proxy->irq = chip->irq;
 799         strscpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
 800         proxy->dev.platform_data = (void *) chip->platform_data;
 801         proxy->controller_data = chip->controller_data;
 802         proxy->controller_state = NULL;
 803         /*
 804          * spi->chip_select[i] gives the corresponding physical CS for logical CS i
 805          * logical CS number is represented by setting the ith bit in spi->cs_index_mask
 806          * So, for example, if spi->cs_index_mask = 0x01 then logical CS number is 0 and
 807          * spi->chip_select[0] will give the physical CS.
 808          * By default spi->chip_select[0] will hold the physical CS number so, set
 809          * spi->cs_index_mask as 0x01.
 810          */
 811         proxy->cs_index_mask = 0x01;
 812
 813         if (chip->swnode) {
 814                 status = device_add_software_node(&proxy->dev, chip->swnode);
 815                 if (status) {
 816                         dev_err(&ctlr->dev, "failed to add software node to '%s': %d\n",
 817                                 chip->modalias, status);
 818                         goto err_dev_put;
 819                 }
 820         }
 821
 822         status = spi_add_device(proxy);
 823         if (status < 0)
 824                 goto err_dev_put;
 825
 826         return proxy;
 827
 828 err_dev_put:
 829         device_remove_software_node(&proxy->dev);
 830         spi_dev_put(proxy);
 831         return NULL;
 832 }
 833 EXPORT_SYMBOL_GPL(spi_new_device);
 834
 835 /**
 836  * spi_unregister_device - unregister a single SPI device
 837  * @spi: spi_device to unregister
 838  *
 839  * Start making the passed SPI device vanish. Normally this would be handled
 840  * by spi_unregister_controller().
 841  */
 842 void spi_unregister_device(struct spi_device *spi)
 843 {
 844         if (!spi)
 845                 return;
 846
 847         if (spi->dev.of_node) {
 848                 of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
 849                 of_node_put(spi->dev.of_node);
 850         }
 851         if (ACPI_COMPANION(&spi->dev))
 852                 acpi_device_clear_enumerated(ACPI_COMPANION(&spi->dev));
 853         device_remove_software_node(&spi->dev);
 854         device_del(&spi->dev);
 855         spi_cleanup(spi);
 856         put_device(&spi->dev);
 857 }
 858 EXPORT_SYMBOL_GPL(spi_unregister_device);
 859
 860 static void spi_match_controller_to_boardinfo(struct spi_controller *ctlr,
 861                                               struct spi_board_info *bi)
 862 {
 863         struct spi_device *dev;
 864
 865         if (ctlr->bus_num != bi->bus_num)
 866                 return;
 867
 868         dev = spi_new_device(ctlr, bi);
 869         if (!dev)
 870                 dev_err(ctlr->dev.parent, "can't create new device for %s\n",
 871                         bi->modalias);
 872 }
 873
 874 /**
 875  * spi_register_board_info - register SPI devices for a given board
 876  * @info: array of chip descriptors
 877  * @n: how many descriptors are provided
 878  * Context: can sleep
 879  *
 880  * Board-specific early init code calls this (probably during arch_initcall)
 881  * with segments of the SPI device table.  Any device nodes are created later,
 882  * after the relevant parent SPI controller (bus_num) is defined.  We keep
 883  * this table of devices forever, so that reloading a controller driver will
 884  * not make Linux forget about these hard-wired devices.
 885  *
 886  * Other code can also call this, e.g. a particular add-on board might provide
 887  * SPI devices through its expansion connector, so code initializing that board
 888  * would naturally declare its SPI devices.
 889  *
 890  * The board info passed can safely be __initdata ... but be careful of
 891  * any embedded pointers (platform_data, etc), they're copied as-is.
 892  *
 893  * Return: zero on success, else a negative error code.
 894  */
 895 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
 896 {
 897         struct boardinfo *bi;
 898         int i;
 899
 900         if (!n)
 901                 return 0;
 902
 903         bi = kcalloc(n, sizeof(*bi), GFP_KERNEL);
 904         if (!bi)
 905                 return -ENOMEM;
 906
 907         for (i = 0; i < n; i++, bi++, info++) {
 908                 struct spi_controller *ctlr;
 909
 910                 memcpy(&bi->board_info, info, sizeof(*info));
 911
 912                 mutex_lock(&board_lock);
 913                 list_add_tail(&bi->list, &board_list);
 914                 list_for_each_entry(ctlr, &spi_controller_list, list)
 915                         spi_match_controller_to_boardinfo(ctlr,
 916                                                           &bi->board_info);
 917                 mutex_unlock(&board_lock);
 918         }
 919
 920         return 0;
 921 }
 922
 923 /*-------------------------------------------------------------------------*/
 924
 925 /* Core methods for SPI resource management */
 926
 927 /**
 928  * spi_res_alloc - allocate a spi resource that is life-cycle managed
 929  *                 during the processing of a spi_message while using
 930  *                 spi_transfer_one
 931  * @spi:     the SPI device for which we allocate memory
 932  * @release: the release code to execute for this resource
 933  * @size:    size to alloc and return
 934  * @gfp:     GFP allocation flags
 935  *
 936  * Return: the pointer to the allocated data
 937  *
 938  * This may get enhanced in the future to allocate from a memory pool
 939  * of the @spi_device or @spi_controller to avoid repeated allocations.
 940  */
 941 static void *spi_res_alloc(struct spi_device *spi, spi_res_release_t release,
 942                            size_t size, gfp_t gfp)
 943 {
 944         struct spi_res *sres;
 945
 946         sres = kzalloc(sizeof(*sres) + size, gfp);
 947         if (!sres)
 948                 return NULL;
 949
 950         INIT_LIST_HEAD(&sres->entry);
 951         sres->release = release;
 952
 953         return sres->data;
 954 }
 955
 956 /**
 957  * spi_res_free - free an SPI resource
 958  * @res: pointer to the custom data of a resource
 959  */
 960 static void spi_res_free(void *res)
 961 {
 962         struct spi_res *sres = container_of(res, struct spi_res, data);
 963
 964         if (!res)
 965                 return;
 966
 967         WARN_ON(!list_empty(&sres->entry));
 968         kfree(sres);
 969 }
 970
 971 /**
 972  * spi_res_add - add a spi_res to the spi_message
 973  * @message: the SPI message
 974  * @res:     the spi_resource
 975  */
 976 static void spi_res_add(struct spi_message *message, void *res)
 977 {
 978         struct spi_res *sres = container_of(res, struct spi_res, data);
 979
 980         WARN_ON(!list_empty(&sres->entry));
 981         list_add_tail(&sres->entry, &message->resources);
 982 }
 983
 984 /**
 985  * spi_res_release - release all SPI resources for this message
 986  * @ctlr:  the @spi_controller
 987  * @message: the @spi_message
 988  */
 989 static void spi_res_release(struct spi_controller *ctlr, struct spi_message *message)
 990 {
 991         struct spi_res *res, *tmp;
 992
 993         list_for_each_entry_safe_reverse(res, tmp, &message->resources, entry) {
 994                 if (res->release)
 995                         res->release(ctlr, message, res->data);
 996
 997                 list_del(&res->entry);
 998
 999                 kfree(res);
1000         }
1001 }
1002
1003 /*-------------------------------------------------------------------------*/
1004 static inline bool spi_is_last_cs(struct spi_device *spi)
1005 {
1006         u8 idx;
1007         bool last = false;
1008
1009         for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) {
1010                 if ((spi->cs_index_mask >> idx) & 0x01) {
1011                         if (spi->controller->last_cs[idx] == spi_get_chipselect(spi, idx))
1012                                 last = true;
1013                 }
1014         }
1015         return last;
1016 }
1017
1018
1019 static void spi_set_cs(struct spi_device *spi, bool enable, bool force)
1020 {
1021         bool activate = enable;
1022         u8 idx;
1023
1024         /*
1025          * Avoid calling into the driver (or doing delays) if the chip select
1026          * isn't actually changing from the last time this was called.
1027          */
1028         if (!force && ((enable && spi->controller->last_cs_index_mask == spi->cs_index_mask &&
1029                         spi_is_last_cs(spi)) ||
1030                        (!enable && spi->controller->last_cs_index_mask == spi->cs_index_mask &&
1031                         !spi_is_last_cs(spi))) &&
1032             (spi->controller->last_cs_mode_high == (spi->mode & SPI_CS_HIGH)))
1033                 return;
1034
1035         trace_spi_set_cs(spi, activate);
1036
1037         spi->controller->last_cs_index_mask = spi->cs_index_mask;
1038         for (idx = 0; idx < SPI_CS_CNT_MAX; idx++)
1039                 spi->controller->last_cs[idx] = enable ? spi_get_chipselect(spi, 0) : -1;
1040         spi->controller->last_cs_mode_high = spi->mode & SPI_CS_HIGH;
1041
1042         if (spi->mode & SPI_CS_HIGH)
1043                 enable = !enable;
1044
1045         /*
1046          * Handle chip select delays for GPIO based CS or controllers without
1047          * programmable chip select timing.
1048          */
1049         if ((spi_is_csgpiod(spi) || !spi->controller->set_cs_timing) && !activate)
1050                 spi_delay_exec(&spi->cs_hold, NULL);
1051
1052         if (spi_is_csgpiod(spi)) {
1053                 if (!(spi->mode & SPI_NO_CS)) {
1054                         /*
1055                          * Historically ACPI has no means of the GPIO polarity and
1056                          * thus the SPISerialBus() resource defines it on the per-chip
1057                          * basis. In order to avoid a chain of negations, the GPIO
1058                          * polarity is considered being Active High. Even for the cases
1059                          * when _DSD() is involved (in the updated versions of ACPI)
1060                          * the GPIO CS polarity must be defined Active High to avoid
1061                          * ambiguity. That's why we use enable, that takes SPI_CS_HIGH
1062                          * into account.
1063                          */
1064                         for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) {
1065                                 if (((spi->cs_index_mask >> idx) & 0x01) &&
1066                                     spi_get_csgpiod(spi, idx)) {
1067                                         if (has_acpi_companion(&spi->dev))
1068                                                 gpiod_set_value_cansleep(spi_get_csgpiod(spi, idx),
1069                                                                          !enable);
1070                                         else
1071                                                 /* Polarity handled by GPIO library */
1072                                                 gpiod_set_value_cansleep(spi_get_csgpiod(spi, idx),
1073                                                                          activate);
1074
1075                                         if (activate)
1076                                                 spi_delay_exec(&spi->cs_setup, NULL);
1077                                         else
1078                                                 spi_delay_exec(&spi->cs_inactive, NULL);
1079                                 }
1080                         }
1081                 }
1082                 /* Some SPI masters need both GPIO CS & slave_select */
1083                 if ((spi->controller->flags & SPI_CONTROLLER_GPIO_SS) &&
1084                     spi->controller->set_cs)
1085                         spi->controller->set_cs(spi, !enable);
1086         } else if (spi->controller->set_cs) {
1087                 spi->controller->set_cs(spi, !enable);
1088         }
1089
1090         if (spi_is_csgpiod(spi) || !spi->controller->set_cs_timing) {
1091                 if (activate)
1092                         spi_delay_exec(&spi->cs_setup, NULL);
1093                 else
1094                         spi_delay_exec(&spi->cs_inactive, NULL);
1095         }
1096 }
1097
1098 #ifdef CONFIG_HAS_DMA
1099 static int spi_map_buf_attrs(struct spi_controller *ctlr, struct device *dev,
1100                              struct sg_table *sgt, void *buf, size_t len,
1101                              enum dma_data_direction dir, unsigned long attrs)
1102 {
1103         const bool vmalloced_buf = is_vmalloc_addr(buf);
1104         unsigned int max_seg_size = dma_get_max_seg_size(dev);
1105 #ifdef CONFIG_HIGHMEM
1106         const bool kmap_buf = ((unsigned long)buf >= PKMAP_BASE &&
1107                                 (unsigned long)buf < (PKMAP_BASE +
1108                                         (LAST_PKMAP * PAGE_SIZE)));
1109 #else
1110         const bool kmap_buf = false;
1111 #endif
1112         int desc_len;
1113         int sgs;
1114         struct page *vm_page;
1115         struct scatterlist *sg;
1116         void *sg_buf;
1117         size_t min;
1118         int i, ret;
1119
1120         if (vmalloced_buf || kmap_buf) {
1121                 desc_len = min_t(unsigned long, max_seg_size, PAGE_SIZE);
1122                 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
1123         } else if (virt_addr_valid(buf)) {
1124                 desc_len = min_t(size_t, max_seg_size, ctlr->max_dma_len);
1125                 sgs = DIV_ROUND_UP(len, desc_len);
1126         } else {
1127                 return -EINVAL;
1128         }
1129
1130         ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
1131         if (ret != 0)
1132                 return ret;
1133
1134         sg = &sgt->sgl[0];
1135         for (i = 0; i < sgs; i++) {
1136
1137                 if (vmalloced_buf || kmap_buf) {
1138                         /*
1139                          * Next scatterlist entry size is the minimum between
1140                          * the desc_len and the remaining buffer length that
1141                          * fits in a page.
1142                          */
1143                         min = min_t(size_t, desc_len,
1144                                     min_t(size_t, len,
1145                                           PAGE_SIZE - offset_in_page(buf)));
1146                         if (vmalloced_buf)
1147                                 vm_page = vmalloc_to_page(buf);
1148                         else
1149                                 vm_page = kmap_to_page(buf);
1150                         if (!vm_page) {
1151                                 sg_free_table(sgt);
1152                                 return -ENOMEM;
1153                         }
1154                         sg_set_page(sg, vm_page,
1155                                     min, offset_in_page(buf));
1156                 } else {
1157                         min = min_t(size_t, len, desc_len);
1158                         sg_buf = buf;
1159                         sg_set_buf(sg, sg_buf, min);
1160                 }
1161
1162                 buf += min;
1163                 len -= min;
1164                 sg = sg_next(sg);
1165         }
1166
1167         ret = dma_map_sgtable(dev, sgt, dir, attrs);
1168         if (ret < 0) {
1169                 sg_free_table(sgt);
1170                 return ret;
1171         }
1172
1173         return 0;
1174 }
1175
1176 int spi_map_buf(struct spi_controller *ctlr, struct device *dev,
1177                 struct sg_table *sgt, void *buf, size_t len,
1178                 enum dma_data_direction dir)
1179 {
1180         return spi_map_buf_attrs(ctlr, dev, sgt, buf, len, dir, 0);
1181 }
1182
1183 static void spi_unmap_buf_attrs(struct spi_controller *ctlr,
1184                                 struct device *dev, struct sg_table *sgt,
1185                                 enum dma_data_direction dir,
1186                                 unsigned long attrs)
1187 {
1188         if (sgt->orig_nents) {
1189                 dma_unmap_sgtable(dev, sgt, dir, attrs);
1190                 sg_free_table(sgt);
1191                 sgt->orig_nents = 0;
1192                 sgt->nents = 0;
1193         }
1194 }
1195
1196 void spi_unmap_buf(struct spi_controller *ctlr, struct device *dev,
1197                    struct sg_table *sgt, enum dma_data_direction dir)
1198 {
1199         spi_unmap_buf_attrs(ctlr, dev, sgt, dir, 0);
1200 }
1201
1202 static int __spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
1203 {
1204         struct device *tx_dev, *rx_dev;
1205         struct spi_transfer *xfer;
1206         int ret;
1207
1208         if (!ctlr->can_dma)
1209                 return 0;
1210
1211         if (ctlr->dma_tx)
1212                 tx_dev = ctlr->dma_tx->device->dev;
1213         else if (ctlr->dma_map_dev)
1214                 tx_dev = ctlr->dma_map_dev;
1215         else
1216                 tx_dev = ctlr->dev.parent;
1217
1218         if (ctlr->dma_rx)
1219                 rx_dev = ctlr->dma_rx->device->dev;
1220         else if (ctlr->dma_map_dev)
1221                 rx_dev = ctlr->dma_map_dev;
1222         else
1223                 rx_dev = ctlr->dev.parent;
1224
1225         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1226                 /* The sync is done before each transfer. */
1227                 unsigned long attrs = DMA_ATTR_SKIP_CPU_SYNC;
1228
1229                 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
1230                         continue;
1231
1232                 if (xfer->tx_buf != NULL) {
1233                         ret = spi_map_buf_attrs(ctlr, tx_dev, &xfer->tx_sg,
1234                                                 (void *)xfer->tx_buf,
1235                                                 xfer->len, DMA_TO_DEVICE,
1236                                                 attrs);
1237                         if (ret != 0)
1238                                 return ret;
1239                 }
1240
1241                 if (xfer->rx_buf != NULL) {
1242                         ret = spi_map_buf_attrs(ctlr, rx_dev, &xfer->rx_sg,
1243                                                 xfer->rx_buf, xfer->len,
1244                                                 DMA_FROM_DEVICE, attrs);
1245                         if (ret != 0) {
1246                                 spi_unmap_buf_attrs(ctlr, tx_dev,
1247                                                 &xfer->tx_sg, DMA_TO_DEVICE,
1248                                                 attrs);
1249
1250                                 return ret;
1251                         }
1252                 }
1253         }
1254
1255         ctlr->cur_rx_dma_dev = rx_dev;
1256         ctlr->cur_tx_dma_dev = tx_dev;
1257         ctlr->cur_msg_mapped = true;
1258
1259         return 0;
1260 }
1261
1262 static int __spi_unmap_msg(struct spi_controller *ctlr, struct spi_message *msg)
1263 {
1264         struct device *rx_dev = ctlr->cur_rx_dma_dev;
1265         struct device *tx_dev = ctlr->cur_tx_dma_dev;
1266         struct spi_transfer *xfer;
1267
1268         if (!ctlr->cur_msg_mapped || !ctlr->can_dma)
1269                 return 0;
1270
1271         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1272                 /* The sync has already been done after each transfer. */
1273                 unsigned long attrs = DMA_ATTR_SKIP_CPU_SYNC;
1274
1275                 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
1276                         continue;
1277
1278                 spi_unmap_buf_attrs(ctlr, rx_dev, &xfer->rx_sg,
1279                                     DMA_FROM_DEVICE, attrs);
1280                 spi_unmap_buf_attrs(ctlr, tx_dev, &xfer->tx_sg,
1281                                     DMA_TO_DEVICE, attrs);
1282         }
1283
1284         ctlr->cur_msg_mapped = false;
1285
1286         return 0;
1287 }
1288
1289 static void spi_dma_sync_for_device(struct spi_controller *ctlr,
1290                                     struct spi_transfer *xfer)
1291 {
1292         struct device *rx_dev = ctlr->cur_rx_dma_dev;
1293         struct device *tx_dev = ctlr->cur_tx_dma_dev;
1294
1295         if (!ctlr->cur_msg_mapped)
1296                 return;
1297
1298         if (xfer->tx_sg.orig_nents)
1299                 dma_sync_sgtable_for_device(tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
1300         if (xfer->rx_sg.orig_nents)
1301                 dma_sync_sgtable_for_device(rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
1302 }
1303
1304 static void spi_dma_sync_for_cpu(struct spi_controller *ctlr,
1305                                  struct spi_transfer *xfer)
1306 {
1307         struct device *rx_dev = ctlr->cur_rx_dma_dev;
1308         struct device *tx_dev = ctlr->cur_tx_dma_dev;
1309
1310         if (!ctlr->cur_msg_mapped)
1311                 return;
1312
1313         if (xfer->rx_sg.orig_nents)
1314                 dma_sync_sgtable_for_cpu(rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
1315         if (xfer->tx_sg.orig_nents)
1316                 dma_sync_sgtable_for_cpu(tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
1317 }
1318 #else /* !CONFIG_HAS_DMA */
1319 static inline int __spi_map_msg(struct spi_controller *ctlr,
1320                                 struct spi_message *msg)
1321 {
1322         return 0;
1323 }
1324
1325 static inline int __spi_unmap_msg(struct spi_controller *ctlr,
1326                                   struct spi_message *msg)
1327 {
1328         return 0;
1329 }
1330
1331 static void spi_dma_sync_for_device(struct spi_controller *ctrl,
1332                                     struct spi_transfer *xfer)
1333 {
1334 }
1335
1336 static void spi_dma_sync_for_cpu(struct spi_controller *ctrl,
1337                                  struct spi_transfer *xfer)
1338 {
1339 }
1340 #endif /* !CONFIG_HAS_DMA */
1341
1342 static inline int spi_unmap_msg(struct spi_controller *ctlr,
1343                                 struct spi_message *msg)
1344 {
1345         struct spi_transfer *xfer;
1346
1347         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1348                 /*
1349                  * Restore the original value of tx_buf or rx_buf if they are
1350                  * NULL.
1351                  */
1352                 if (xfer->tx_buf == ctlr->dummy_tx)
1353                         xfer->tx_buf = NULL;
1354                 if (xfer->rx_buf == ctlr->dummy_rx)
1355                         xfer->rx_buf = NULL;
1356         }
1357
1358         return __spi_unmap_msg(ctlr, msg);
1359 }
1360
1361 static int spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
1362 {
1363         struct spi_transfer *xfer;
1364         void *tmp;
1365         unsigned int max_tx, max_rx;
1366
1367         if ((ctlr->flags & (SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX))
1368                 && !(msg->spi->mode & SPI_3WIRE)) {
1369                 max_tx = 0;
1370                 max_rx = 0;
1371
1372                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1373                         if ((ctlr->flags & SPI_CONTROLLER_MUST_TX) &&
1374                             !xfer->tx_buf)
1375                                 max_tx = max(xfer->len, max_tx);
1376                         if ((ctlr->flags & SPI_CONTROLLER_MUST_RX) &&
1377                             !xfer->rx_buf)
1378                                 max_rx = max(xfer->len, max_rx);
1379                 }
1380
1381                 if (max_tx) {
1382                         tmp = krealloc(ctlr->dummy_tx, max_tx,
1383                                        GFP_KERNEL | GFP_DMA | __GFP_ZERO);
1384                         if (!tmp)
1385                                 return -ENOMEM;
1386                         ctlr->dummy_tx = tmp;
1387                 }
1388
1389                 if (max_rx) {
1390                         tmp = krealloc(ctlr->dummy_rx, max_rx,
1391                                        GFP_KERNEL | GFP_DMA);
1392                         if (!tmp)
1393                                 return -ENOMEM;
1394                         ctlr->dummy_rx = tmp;
1395                 }
1396
1397                 if (max_tx || max_rx) {
1398                         list_for_each_entry(xfer, &msg->transfers,
1399                                             transfer_list) {
1400                                 if (!xfer->len)
1401                                         continue;
1402                                 if (!xfer->tx_buf)
1403                                         xfer->tx_buf = ctlr->dummy_tx;
1404                                 if (!xfer->rx_buf)
1405                                         xfer->rx_buf = ctlr->dummy_rx;
1406                         }
1407                 }
1408         }
1409
1410         return __spi_map_msg(ctlr, msg);
1411 }
1412
1413 static int spi_transfer_wait(struct spi_controller *ctlr,
1414                              struct spi_message *msg,
1415                              struct spi_transfer *xfer)
1416 {
1417         struct spi_statistics __percpu *statm = ctlr->pcpu_statistics;
1418         struct spi_statistics __percpu *stats = msg->spi->pcpu_statistics;
1419         u32 speed_hz = xfer->speed_hz;
1420         unsigned long long ms;
1421
1422         if (spi_controller_is_slave(ctlr)) {
1423                 if (wait_for_completion_interruptible(&ctlr->xfer_completion)) {
1424                         dev_dbg(&msg->spi->dev, "SPI transfer interrupted\n");
1425                         return -EINTR;
1426                 }
1427         } else {
1428                 if (!speed_hz)
1429                         speed_hz = 100000;
1430
1431                 /*
1432                  * For each byte we wait for 8 cycles of the SPI clock.
1433                  * Since speed is defined in Hz and we want milliseconds,
1434                  * use respective multiplier, but before the division,
1435                  * otherwise we may get 0 for short transfers.
1436                  */
1437                 ms = 8LL * MSEC_PER_SEC * xfer->len;
1438                 do_div(ms, speed_hz);
1439
1440                 /*
1441                  * Increase it twice and add 200 ms tolerance, use
1442                  * predefined maximum in case of overflow.
1443                  */
1444                 ms += ms + 200;
1445                 if (ms > UINT_MAX)
1446                         ms = UINT_MAX;
1447
1448                 ms = wait_for_completion_timeout(&ctlr->xfer_completion,
1449                                                  msecs_to_jiffies(ms));
1450
1451                 if (ms == 0) {
1452                         SPI_STATISTICS_INCREMENT_FIELD(statm, timedout);
1453                         SPI_STATISTICS_INCREMENT_FIELD(stats, timedout);
1454                         dev_err(&msg->spi->dev,
1455                                 "SPI transfer timed out\n");
1456                         return -ETIMEDOUT;
1457                 }
1458
1459                 if (xfer->error & SPI_TRANS_FAIL_IO)
1460                         return -EIO;
1461         }
1462
1463         return 0;
1464 }
1465
1466 static void _spi_transfer_delay_ns(u32 ns)
1467 {
1468         if (!ns)
1469                 return;
1470         if (ns <= NSEC_PER_USEC) {
1471                 ndelay(ns);
1472         } else {
1473                 u32 us = DIV_ROUND_UP(ns, NSEC_PER_USEC);
1474
1475                 if (us <= 10)
1476                         udelay(us);
1477                 else
1478                         usleep_range(us, us + DIV_ROUND_UP(us, 10));
1479         }
1480 }
1481
1482 int spi_delay_to_ns(struct spi_delay *_delay, struct spi_transfer *xfer)
1483 {
1484         u32 delay = _delay->value;
1485         u32 unit = _delay->unit;
1486         u32 hz;
1487
1488         if (!delay)
1489                 return 0;
1490
1491         switch (unit) {
1492         case SPI_DELAY_UNIT_USECS:
1493                 delay *= NSEC_PER_USEC;
1494                 break;
1495         case SPI_DELAY_UNIT_NSECS:
1496                 /* Nothing to do here */
1497                 break;
1498         case SPI_DELAY_UNIT_SCK:
1499                 /* Clock cycles need to be obtained from spi_transfer */
1500                 if (!xfer)
1501                         return -EINVAL;
1502                 /*
1503                  * If there is unknown effective speed, approximate it
1504                  * by underestimating with half of the requested Hz.
1505                  */
1506                 hz = xfer->effective_speed_hz ?: xfer->speed_hz / 2;
1507                 if (!hz)
1508                         return -EINVAL;
1509
1510                 /* Convert delay to nanoseconds */
1511                 delay *= DIV_ROUND_UP(NSEC_PER_SEC, hz);
1512                 break;
1513         default:
1514                 return -EINVAL;
1515         }
1516
1517         return delay;
1518 }
1519 EXPORT_SYMBOL_GPL(spi_delay_to_ns);
1520
1521 int spi_delay_exec(struct spi_delay *_delay, struct spi_transfer *xfer)
1522 {
1523         int delay;
1524
1525         might_sleep();
1526
1527         if (!_delay)
1528                 return -EINVAL;
1529
1530         delay = spi_delay_to_ns(_delay, xfer);
1531         if (delay < 0)
1532                 return delay;
1533
1534         _spi_transfer_delay_ns(delay);
1535
1536         return 0;
1537 }
1538 EXPORT_SYMBOL_GPL(spi_delay_exec);
1539
1540 static void _spi_transfer_cs_change_delay(struct spi_message *msg,
1541                                           struct spi_transfer *xfer)
1542 {
1543         u32 default_delay_ns = 10 * NSEC_PER_USEC;
1544         u32 delay = xfer->cs_change_delay.value;
1545         u32 unit = xfer->cs_change_delay.unit;
1546         int ret;
1547
1548         /* Return early on "fast" mode - for everything but USECS */
1549         if (!delay) {
1550                 if (unit == SPI_DELAY_UNIT_USECS)
1551                         _spi_transfer_delay_ns(default_delay_ns);
1552                 return;
1553         }
1554
1555         ret = spi_delay_exec(&xfer->cs_change_delay, xfer);
1556         if (ret) {
1557                 dev_err_once(&msg->spi->dev,
1558                              "Use of unsupported delay unit %i, using default of %luus\n",
1559                              unit, default_delay_ns / NSEC_PER_USEC);
1560                 _spi_transfer_delay_ns(default_delay_ns);
1561         }
1562 }
1563
1564 void spi_transfer_cs_change_delay_exec(struct spi_message *msg,
1565                                                   struct spi_transfer *xfer)
1566 {
1567         _spi_transfer_cs_change_delay(msg, xfer);
1568 }
1569 EXPORT_SYMBOL_GPL(spi_transfer_cs_change_delay_exec);
1570
1571 /*
1572  * spi_transfer_one_message - Default implementation of transfer_one_message()
1573  *
1574  * This is a standard implementation of transfer_one_message() for
1575  * drivers which implement a transfer_one() operation.  It provides
1576  * standard handling of delays and chip select management.
1577  */
1578 static int spi_transfer_one_message(struct spi_controller *ctlr,
1579                                     struct spi_message *msg)
1580 {
1581         struct spi_transfer *xfer;
1582         bool keep_cs = false;
1583         int ret = 0;
1584         struct spi_statistics __percpu *statm = ctlr->pcpu_statistics;
1585         struct spi_statistics __percpu *stats = msg->spi->pcpu_statistics;
1586
1587         xfer = list_first_entry(&msg->transfers, struct spi_transfer, transfer_list);
1588         spi_set_cs(msg->spi, !xfer->cs_off, false);
1589
1590         SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
1591         SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
1592
1593         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1594                 trace_spi_transfer_start(msg, xfer);
1595
1596                 spi_statistics_add_transfer_stats(statm, xfer, ctlr);
1597                 spi_statistics_add_transfer_stats(stats, xfer, ctlr);
1598
1599                 if (!ctlr->ptp_sts_supported) {
1600                         xfer->ptp_sts_word_pre = 0;
1601                         ptp_read_system_prets(xfer->ptp_sts);
1602                 }
1603
1604                 if ((xfer->tx_buf || xfer->rx_buf) && xfer->len) {
1605                         reinit_completion(&ctlr->xfer_completion);
1606
1607 fallback_pio:
1608                         spi_dma_sync_for_device(ctlr, xfer);
1609                         ret = ctlr->transfer_one(ctlr, msg->spi, xfer);
1610                         if (ret < 0) {
1611                                 spi_dma_sync_for_cpu(ctlr, xfer);
1612
1613                                 if (ctlr->cur_msg_mapped &&
1614                                    (xfer->error & SPI_TRANS_FAIL_NO_START)) {
1615                                         __spi_unmap_msg(ctlr, msg);
1616                                         ctlr->fallback = true;
1617                                         xfer->error &= ~SPI_TRANS_FAIL_NO_START;
1618                                         goto fallback_pio;
1619                                 }
1620
1621                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
1622                                                                errors);
1623                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
1624                                                                errors);
1625                                 dev_err(&msg->spi->dev,
1626                                         "SPI transfer failed: %d\n", ret);
1627                                 goto out;
1628                         }
1629
1630                         if (ret > 0) {
1631                                 ret = spi_transfer_wait(ctlr, msg, xfer);
1632                                 if (ret < 0)
1633                                         msg->status = ret;
1634                         }
1635
1636                         spi_dma_sync_for_cpu(ctlr, xfer);
1637                 } else {
1638                         if (xfer->len)
1639                                 dev_err(&msg->spi->dev,
1640                                         "Bufferless transfer has length %u\n",
1641                                         xfer->len);
1642                 }
1643
1644                 if (!ctlr->ptp_sts_supported) {
1645                         ptp_read_system_postts(xfer->ptp_sts);
1646                         xfer->ptp_sts_word_post = xfer->len;
1647                 }
1648
1649                 trace_spi_transfer_stop(msg, xfer);
1650
1651                 if (msg->status != -EINPROGRESS)
1652                         goto out;
1653
1654                 spi_transfer_delay_exec(xfer);
1655
1656                 if (xfer->cs_change) {
1657                         if (list_is_last(&xfer->transfer_list,
1658                                          &msg->transfers)) {
1659                                 keep_cs = true;
1660                         } else {
1661                                 if (!xfer->cs_off)
1662                                         spi_set_cs(msg->spi, false, false);
1663                                 _spi_transfer_cs_change_delay(msg, xfer);
1664                                 if (!list_next_entry(xfer, transfer_list)->cs_off)
1665                                         spi_set_cs(msg->spi, true, false);
1666                         }
1667                 } else if (!list_is_last(&xfer->transfer_list, &msg->transfers) &&
1668                            xfer->cs_off != list_next_entry(xfer, transfer_list)->cs_off) {
1669                         spi_set_cs(msg->spi, xfer->cs_off, false);
1670                 }
1671
1672                 msg->actual_length += xfer->len;
1673         }
1674
1675 out:
1676         if (ret != 0 || !keep_cs)
1677                 spi_set_cs(msg->spi, false, false);
1678
1679         if (msg->status == -EINPROGRESS)
1680                 msg->status = ret;
1681
1682         if (msg->status && ctlr->handle_err)
1683                 ctlr->handle_err(ctlr, msg);
1684
1685         spi_finalize_current_message(ctlr);
1686
1687         return ret;
1688 }
1689
1690 /**
1691  * spi_finalize_current_transfer - report completion of a transfer
1692  * @ctlr: the controller reporting completion
1693  *
1694  * Called by SPI drivers using the core transfer_one_message()
1695  * implementation to notify it that the current interrupt driven
1696  * transfer has finished and the next one may be scheduled.
1697  */
1698 void spi_finalize_current_transfer(struct spi_controller *ctlr)
1699 {
1700         complete(&ctlr->xfer_completion);
1701 }
1702 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1703
1704 static void spi_idle_runtime_pm(struct spi_controller *ctlr)
1705 {
1706         if (ctlr->auto_runtime_pm) {
1707                 pm_runtime_mark_last_busy(ctlr->dev.parent);
1708                 pm_runtime_put_autosuspend(ctlr->dev.parent);
1709         }
1710 }
1711
1712 static int __spi_pump_transfer_message(struct spi_controller *ctlr,
1713                 struct spi_message *msg, bool was_busy)
1714 {
1715         struct spi_transfer *xfer;
1716         int ret;
1717
1718         if (!was_busy && ctlr->auto_runtime_pm) {
1719                 ret = pm_runtime_get_sync(ctlr->dev.parent);
1720                 if (ret < 0) {
1721                         pm_runtime_put_noidle(ctlr->dev.parent);
1722                         dev_err(&ctlr->dev, "Failed to power device: %d\n",
1723                                 ret);
1724
1725                         msg->status = ret;
1726                         spi_finalize_current_message(ctlr);
1727
1728                         return ret;
1729                 }
1730         }
1731
1732         if (!was_busy)
1733                 trace_spi_controller_busy(ctlr);
1734
1735         if (!was_busy && ctlr->prepare_transfer_hardware) {
1736                 ret = ctlr->prepare_transfer_hardware(ctlr);
1737                 if (ret) {
1738                         dev_err(&ctlr->dev,
1739                                 "failed to prepare transfer hardware: %d\n",
1740                                 ret);
1741
1742                         if (ctlr->auto_runtime_pm)
1743                                 pm_runtime_put(ctlr->dev.parent);
1744
1745                         msg->status = ret;
1746                         spi_finalize_current_message(ctlr);
1747
1748                         return ret;
1749                 }
1750         }
1751
1752         trace_spi_message_start(msg);
1753
1754         /*
1755          * If an SPI controller does not support toggling the CS line on each
1756          * transfer (indicated by the SPI_CS_WORD flag) or we are using a GPIO
1757          * for the CS line, we can emulate the CS-per-word hardware function by
1758          * splitting transfers into one-word transfers and ensuring that
1759          * cs_change is set for each transfer.
1760          */
1761         if ((msg->spi->mode & SPI_CS_WORD) && (!(ctlr->mode_bits & SPI_CS_WORD) ||
1762                                                spi_is_csgpiod(msg->spi))) {
1763                 ret = spi_split_transfers_maxwords(ctlr, msg, 1, GFP_KERNEL);
1764                 if (ret) {
1765                         msg->status = ret;
1766                         spi_finalize_current_message(ctlr);
1767                         return ret;
1768                 }
1769
1770                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1771                         /* Don't change cs_change on the last entry in the list */
1772                         if (list_is_last(&xfer->transfer_list, &msg->transfers))
1773                                 break;
1774                         xfer->cs_change = 1;
1775                 }
1776         } else {
1777                 ret = spi_split_transfers_maxsize(ctlr, msg,
1778                                                   spi_max_transfer_size(msg->spi),
1779                                                   GFP_KERNEL | GFP_DMA);
1780                 if (ret) {
1781                         msg->status = ret;
1782                         spi_finalize_current_message(ctlr);
1783                         return ret;
1784                 }
1785         }
1786
1787         if (ctlr->prepare_message) {
1788                 ret = ctlr->prepare_message(ctlr, msg);
1789                 if (ret) {
1790                         dev_err(&ctlr->dev, "failed to prepare message: %d\n",
1791                                 ret);
1792                         msg->status = ret;
1793                         spi_finalize_current_message(ctlr);
1794                         return ret;
1795                 }
1796                 msg->prepared = true;
1797         }
1798
1799         ret = spi_map_msg(ctlr, msg);
1800         if (ret) {
1801                 msg->status = ret;
1802                 spi_finalize_current_message(ctlr);
1803                 return ret;
1804         }
1805
1806         if (!ctlr->ptp_sts_supported && !ctlr->transfer_one) {
1807                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1808                         xfer->ptp_sts_word_pre = 0;
1809                         ptp_read_system_prets(xfer->ptp_sts);
1810                 }
1811         }
1812
1813         /*
1814          * Drivers implementation of transfer_one_message() must arrange for
1815          * spi_finalize_current_message() to get called. Most drivers will do
1816          * this in the calling context, but some don't. For those cases, a
1817          * completion is used to guarantee that this function does not return
1818          * until spi_finalize_current_message() is done accessing
1819          * ctlr->cur_msg.
1820          * Use of the following two flags enable to opportunistically skip the
1821          * use of the completion since its use involves expensive spin locks.
1822          * In case of a race with the context that calls
1823          * spi_finalize_current_message() the completion will always be used,
1824          * due to strict ordering of these flags using barriers.
1825          */
1826         WRITE_ONCE(ctlr->cur_msg_incomplete, true);
1827         WRITE_ONCE(ctlr->cur_msg_need_completion, false);
1828         reinit_completion(&ctlr->cur_msg_completion);
1829         smp_wmb(); /* Make these available to spi_finalize_current_message() */
1830
1831         ret = ctlr->transfer_one_message(ctlr, msg);
1832         if (ret) {
1833                 dev_err(&ctlr->dev,
1834                         "failed to transfer one message from queue\n");
1835                 return ret;
1836         }
1837
1838         WRITE_ONCE(ctlr->cur_msg_need_completion, true);
1839         smp_mb(); /* See spi_finalize_current_message()... */
1840         if (READ_ONCE(ctlr->cur_msg_incomplete))
1841                 wait_for_completion(&ctlr->cur_msg_completion);
1842
1843         return 0;
1844 }
1845
1846 /**
1847  * __spi_pump_messages - function which processes SPI message queue
1848  * @ctlr: controller to process queue for
1849  * @in_kthread: true if we are in the context of the message pump thread
1850  *
1851  * This function checks if there is any SPI message in the queue that
1852  * needs processing and if so call out to the driver to initialize hardware
1853  * and transfer each message.
1854  *
1855  * Note that it is called both from the kthread itself and also from
1856  * inside spi_sync(); the queue extraction handling at the top of the
1857  * function should deal with this safely.
1858  */
1859 static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread)
1860 {
1861         struct spi_message *msg;
1862         bool was_busy = false;
1863         unsigned long flags;
1864         int ret;
1865
1866         /* Take the I/O mutex */
1867         mutex_lock(&ctlr->io_mutex);
1868
1869         /* Lock queue */
1870         spin_lock_irqsave(&ctlr->queue_lock, flags);
1871
1872         /* Make sure we are not already running a message */
1873         if (ctlr->cur_msg)
1874                 goto out_unlock;
1875
1876         /* Check if the queue is idle */
1877         if (list_empty(&ctlr->queue) || !ctlr->running) {
1878                 if (!ctlr->busy)
1879                         goto out_unlock;
1880
1881                 /* Defer any non-atomic teardown to the thread */
1882                 if (!in_kthread) {
1883                         if (!ctlr->dummy_rx && !ctlr->dummy_tx &&
1884                             !ctlr->unprepare_transfer_hardware) {
1885                                 spi_idle_runtime_pm(ctlr);
1886                                 ctlr->busy = false;
1887                                 ctlr->queue_empty = true;
1888                                 trace_spi_controller_idle(ctlr);
1889                         } else {
1890                                 kthread_queue_work(ctlr->kworker,
1891                                                    &ctlr->pump_messages);
1892                         }
1893                         goto out_unlock;
1894                 }
1895
1896                 ctlr->busy = false;
1897                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1898
1899                 kfree(ctlr->dummy_rx);
1900                 ctlr->dummy_rx = NULL;
1901                 kfree(ctlr->dummy_tx);
1902                 ctlr->dummy_tx = NULL;
1903                 if (ctlr->unprepare_transfer_hardware &&
1904                     ctlr->unprepare_transfer_hardware(ctlr))
1905                         dev_err(&ctlr->dev,
1906                                 "failed to unprepare transfer hardware\n");
1907                 spi_idle_runtime_pm(ctlr);
1908                 trace_spi_controller_idle(ctlr);
1909
1910                 spin_lock_irqsave(&ctlr->queue_lock, flags);
1911                 ctlr->queue_empty = true;
1912                 goto out_unlock;
1913         }
1914
1915         /* Extract head of queue */
1916         msg = list_first_entry(&ctlr->queue, struct spi_message, queue);
1917         ctlr->cur_msg = msg;
1918
1919         list_del_init(&msg->queue);
1920         if (ctlr->busy)
1921                 was_busy = true;
1922         else
1923                 ctlr->busy = true;
1924         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1925
1926         ret = __spi_pump_transfer_message(ctlr, msg, was_busy);
1927         kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1928
1929         ctlr->cur_msg = NULL;
1930         ctlr->fallback = false;
1931
1932         mutex_unlock(&ctlr->io_mutex);
1933
1934         /* Prod the scheduler in case transfer_one() was busy waiting */
1935         if (!ret)
1936                 cond_resched();
1937         return;
1938
1939 out_unlock:
1940         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1941         mutex_unlock(&ctlr->io_mutex);
1942 }
1943
1944 /**
1945  * spi_pump_messages - kthread work function which processes spi message queue
1946  * @work: pointer to kthread work struct contained in the controller struct
1947  */
1948 static void spi_pump_messages(struct kthread_work *work)
1949 {
1950         struct spi_controller *ctlr =
1951                 container_of(work, struct spi_controller, pump_messages);
1952
1953         __spi_pump_messages(ctlr, true);
1954 }
1955
1956 /**
1957  * spi_take_timestamp_pre - helper to collect the beginning of the TX timestamp
1958  * @ctlr: Pointer to the spi_controller structure of the driver
1959  * @xfer: Pointer to the transfer being timestamped
1960  * @progress: How many words (not bytes) have been transferred so far
1961  * @irqs_off: If true, will disable IRQs and preemption for the duration of the
1962  *            transfer, for less jitter in time measurement. Only compatible
1963  *            with PIO drivers. If true, must follow up with
1964  *            spi_take_timestamp_post or otherwise system will crash.
1965  *            WARNING: for fully predictable results, the CPU frequency must
1966  *            also be under control (governor).
1967  *
1968  * This is a helper for drivers to collect the beginning of the TX timestamp
1969  * for the requested byte from the SPI transfer. The frequency with which this
1970  * function must be called (once per word, once for the whole transfer, once
1971  * per batch of words etc) is arbitrary as long as the @tx buffer offset is
1972  * greater than or equal to the requested byte at the time of the call. The
1973  * timestamp is only taken once, at the first such call. It is assumed that
1974  * the driver advances its @tx buffer pointer monotonically.
1975  */
1976 void spi_take_timestamp_pre(struct spi_controller *ctlr,
1977                             struct spi_transfer *xfer,
1978                             size_t progress, bool irqs_off)
1979 {
1980         if (!xfer->ptp_sts)
1981                 return;
1982
1983         if (xfer->timestamped)
1984                 return;
1985
1986         if (progress > xfer->ptp_sts_word_pre)
1987                 return;
1988
1989         /* Capture the resolution of the timestamp */
1990         xfer->ptp_sts_word_pre = progress;
1991
1992         if (irqs_off) {
1993                 local_irq_save(ctlr->irq_flags);
1994                 preempt_disable();
1995         }
1996
1997         ptp_read_system_prets(xfer->ptp_sts);
1998 }
1999 EXPORT_SYMBOL_GPL(spi_take_timestamp_pre);
2000
2001 /**
2002  * spi_take_timestamp_post - helper to collect the end of the TX timestamp
2003  * @ctlr: Pointer to the spi_controller structure of the driver
2004  * @xfer: Pointer to the transfer being timestamped
2005  * @progress: How many words (not bytes) have been transferred so far
2006  * @irqs_off: If true, will re-enable IRQs and preemption for the local CPU.
2007  *
2008  * This is a helper for drivers to collect the end of the TX timestamp for
2009  * the requested byte from the SPI transfer. Can be called with an arbitrary
2010  * frequency: only the first call where @tx exceeds or is equal to the
2011  * requested word will be timestamped.
2012  */
2013 void spi_take_timestamp_post(struct spi_controller *ctlr,
2014                              struct spi_transfer *xfer,
2015                              size_t progress, bool irqs_off)
2016 {
2017         if (!xfer->ptp_sts)
2018                 return;
2019
2020         if (xfer->timestamped)
2021                 return;
2022
2023         if (progress < xfer->ptp_sts_word_post)
2024                 return;
2025
2026         ptp_read_system_postts(xfer->ptp_sts);
2027
2028         if (irqs_off) {
2029                 local_irq_restore(ctlr->irq_flags);
2030                 preempt_enable();
2031         }
2032
2033         /* Capture the resolution of the timestamp */
2034         xfer->ptp_sts_word_post = progress;
2035
2036         xfer->timestamped = 1;
2037 }
2038 EXPORT_SYMBOL_GPL(spi_take_timestamp_post);
2039
2040 /**
2041  * spi_set_thread_rt - set the controller to pump at realtime priority
2042  * @ctlr: controller to boost priority of
2043  *
2044  * This can be called because the controller requested realtime priority
2045  * (by setting the ->rt value before calling spi_register_controller()) or
2046  * because a device on the bus said that its transfers needed realtime
2047  * priority.
2048  *
2049  * NOTE: at the moment if any device on a bus says it needs realtime then
2050  * the thread will be at realtime priority for all transfers on that
2051  * controller.  If this eventually becomes a problem we may see if we can
2052  * find a way to boost the priority only temporarily during relevant
2053  * transfers.
2054  */
2055 static void spi_set_thread_rt(struct spi_controller *ctlr)
2056 {
2057         dev_info(&ctlr->dev,
2058                 "will run message pump with realtime priority\n");
2059         sched_set_fifo(ctlr->kworker->task);
2060 }
2061
2062 static int spi_init_queue(struct spi_controller *ctlr)
2063 {
2064         ctlr->running = false;
2065         ctlr->busy = false;
2066         ctlr->queue_empty = true;
2067
2068         ctlr->kworker = kthread_create_worker(0, dev_name(&ctlr->dev));
2069         if (IS_ERR(ctlr->kworker)) {
2070                 dev_err(&ctlr->dev, "failed to create message pump kworker\n");
2071                 return PTR_ERR(ctlr->kworker);
2072         }
2073
2074         kthread_init_work(&ctlr->pump_messages, spi_pump_messages);
2075
2076         /*
2077          * Controller config will indicate if this controller should run the
2078          * message pump with high (realtime) priority to reduce the transfer
2079          * latency on the bus by minimising the delay between a transfer
2080          * request and the scheduling of the message pump thread. Without this
2081          * setting the message pump thread will remain at default priority.
2082          */
2083         if (ctlr->rt)
2084                 spi_set_thread_rt(ctlr);
2085
2086         return 0;
2087 }
2088
2089 /**
2090  * spi_get_next_queued_message() - called by driver to check for queued
2091  * messages
2092  * @ctlr: the controller to check for queued messages
2093  *
2094  * If there are more messages in the queue, the next message is returned from
2095  * this call.
2096  *
2097  * Return: the next message in the queue, else NULL if the queue is empty.
2098  */
2099 struct spi_message *spi_get_next_queued_message(struct spi_controller *ctlr)
2100 {
2101         struct spi_message *next;
2102         unsigned long flags;
2103
2104         /* Get a pointer to the next message, if any */
2105         spin_lock_irqsave(&ctlr->queue_lock, flags);
2106         next = list_first_entry_or_null(&ctlr->queue, struct spi_message,
2107                                         queue);
2108         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2109
2110         return next;
2111 }
2112 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
2113
2114 /**
2115  * spi_finalize_current_message() - the current message is complete
2116  * @ctlr: the controller to return the message to
2117  *
2118  * Called by the driver to notify the core that the message in the front of the
2119  * queue is complete and can be removed from the queue.
2120  */
2121 void spi_finalize_current_message(struct spi_controller *ctlr)
2122 {
2123         struct spi_transfer *xfer;
2124         struct spi_message *mesg;
2125         int ret;
2126
2127         mesg = ctlr->cur_msg;
2128
2129         if (!ctlr->ptp_sts_supported && !ctlr->transfer_one) {
2130                 list_for_each_entry(xfer, &mesg->transfers, transfer_list) {
2131                         ptp_read_system_postts(xfer->ptp_sts);
2132                         xfer->ptp_sts_word_post = xfer->len;
2133                 }
2134         }
2135
2136         if (unlikely(ctlr->ptp_sts_supported))
2137                 list_for_each_entry(xfer, &mesg->transfers, transfer_list)
2138                         WARN_ON_ONCE(xfer->ptp_sts && !xfer->timestamped);
2139
2140         spi_unmap_msg(ctlr, mesg);
2141
2142         /*
2143          * In the prepare_messages callback the SPI bus has the opportunity
2144          * to split a transfer to smaller chunks.
2145          *
2146          * Release the split transfers here since spi_map_msg() is done on
2147          * the split transfers.
2148          */
2149         spi_res_release(ctlr, mesg);
2150
2151         if (mesg->prepared && ctlr->unprepare_message) {
2152                 ret = ctlr->unprepare_message(ctlr, mesg);
2153                 if (ret) {
2154                         dev_err(&ctlr->dev, "failed to unprepare message: %d\n",
2155                                 ret);
2156                 }
2157         }
2158
2159         mesg->prepared = false;
2160
2161         WRITE_ONCE(ctlr->cur_msg_incomplete, false);
2162         smp_mb(); /* See __spi_pump_transfer_message()... */
2163         if (READ_ONCE(ctlr->cur_msg_need_completion))
2164                 complete(&ctlr->cur_msg_completion);
2165
2166         trace_spi_message_done(mesg);
2167
2168         mesg->state = NULL;
2169         if (mesg->complete)
2170                 mesg->complete(mesg->context);
2171 }
2172 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
2173
2174 static int spi_start_queue(struct spi_controller *ctlr)
2175 {
2176         unsigned long flags;
2177
2178         spin_lock_irqsave(&ctlr->queue_lock, flags);
2179
2180         if (ctlr->running || ctlr->busy) {
2181                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2182                 return -EBUSY;
2183         }
2184
2185         ctlr->running = true;
2186         ctlr->cur_msg = NULL;
2187         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2188
2189         kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
2190
2191         return 0;
2192 }
2193
2194 static int spi_stop_queue(struct spi_controller *ctlr)
2195 {
2196         unsigned long flags;
2197         unsigned limit = 500;
2198         int ret = 0;
2199
2200         spin_lock_irqsave(&ctlr->queue_lock, flags);
2201
2202         /*
2203          * This is a bit lame, but is optimized for the common execution path.
2204          * A wait_queue on the ctlr->busy could be used, but then the common
2205          * execution path (pump_messages) would be required to call wake_up or
2206          * friends on every SPI message. Do this instead.
2207          */
2208         while ((!list_empty(&ctlr->queue) || ctlr->busy) && limit--) {
2209                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2210                 usleep_range(10000, 11000);
2211                 spin_lock_irqsave(&ctlr->queue_lock, flags);
2212         }
2213
2214         if (!list_empty(&ctlr->queue) || ctlr->busy)
2215                 ret = -EBUSY;
2216         else
2217                 ctlr->running = false;
2218
2219         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2220
2221         return ret;
2222 }
2223
2224 static int spi_destroy_queue(struct spi_controller *ctlr)
2225 {
2226         int ret;
2227
2228         ret = spi_stop_queue(ctlr);
2229
2230         /*
2231          * kthread_flush_worker will block until all work is done.
2232          * If the reason that stop_queue timed out is that the work will never
2233          * finish, then it does no good to call flush/stop thread, so
2234          * return anyway.
2235          */
2236         if (ret) {
2237                 dev_err(&ctlr->dev, "problem destroying queue\n");
2238                 return ret;
2239         }
2240
2241         kthread_destroy_worker(ctlr->kworker);
2242
2243         return 0;
2244 }
2245
2246 static int __spi_queued_transfer(struct spi_device *spi,
2247                                  struct spi_message *msg,
2248                                  bool need_pump)
2249 {
2250         struct spi_controller *ctlr = spi->controller;
2251         unsigned long flags;
2252
2253         spin_lock_irqsave(&ctlr->queue_lock, flags);
2254
2255         if (!ctlr->running) {
2256                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2257                 return -ESHUTDOWN;
2258         }
2259         msg->actual_length = 0;
2260         msg->status = -EINPROGRESS;
2261
2262         list_add_tail(&msg->queue, &ctlr->queue);
2263         ctlr->queue_empty = false;
2264         if (!ctlr->busy && need_pump)
2265                 kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
2266
2267         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2268         return 0;
2269 }
2270
2271 /**
2272  * spi_queued_transfer - transfer function for queued transfers
2273  * @spi: SPI device which is requesting transfer
2274  * @msg: SPI message which is to handled is queued to driver queue
2275  *
2276  * Return: zero on success, else a negative error code.
2277  */
2278 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
2279 {
2280         return __spi_queued_transfer(spi, msg, true);
2281 }
2282
2283 static int spi_controller_initialize_queue(struct spi_controller *ctlr)
2284 {
2285         int ret;
2286
2287         ctlr->transfer = spi_queued_transfer;
2288         if (!ctlr->transfer_one_message)
2289                 ctlr->transfer_one_message = spi_transfer_one_message;
2290
2291         /* Initialize and start queue */
2292         ret = spi_init_queue(ctlr);
2293         if (ret) {
2294                 dev_err(&ctlr->dev, "problem initializing queue\n");
2295                 goto err_init_queue;
2296         }
2297         ctlr->queued = true;
2298         ret = spi_start_queue(ctlr);
2299         if (ret) {
2300                 dev_err(&ctlr->dev, "problem starting queue\n");
2301                 goto err_start_queue;
2302         }
2303
2304         return 0;
2305
2306 err_start_queue:
2307         spi_destroy_queue(ctlr);
2308 err_init_queue:
2309         return ret;
2310 }
2311
2312 /**
2313  * spi_flush_queue - Send all pending messages in the queue from the callers'
2314  *                   context
2315  * @ctlr: controller to process queue for
2316  *
2317  * This should be used when one wants to ensure all pending messages have been
2318  * sent before doing something. Is used by the spi-mem code to make sure SPI
2319  * memory operations do not preempt regular SPI transfers that have been queued
2320  * before the spi-mem operation.
2321  */
2322 void spi_flush_queue(struct spi_controller *ctlr)
2323 {
2324         if (ctlr->transfer == spi_queued_transfer)
2325                 __spi_pump_messages(ctlr, false);
2326 }
2327
2328 /*-------------------------------------------------------------------------*/
2329
2330 #if defined(CONFIG_OF)
2331 static void of_spi_parse_dt_cs_delay(struct device_node *nc,
2332                                      struct spi_delay *delay, const char *prop)
2333 {
2334         u32 value;
2335
2336         if (!of_property_read_u32(nc, prop, &value)) {
2337                 if (value > U16_MAX) {
2338                         delay->value = DIV_ROUND_UP(value, 1000);
2339                         delay->unit = SPI_DELAY_UNIT_USECS;
2340                 } else {
2341                         delay->value = value;
2342                         delay->unit = SPI_DELAY_UNIT_NSECS;
2343                 }
2344         }
2345 }
2346
2347 static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
2348                            struct device_node *nc)
2349 {
2350         u32 value, cs[SPI_CS_CNT_MAX];
2351         int rc, idx;
2352
2353         /* Mode (clock phase/polarity/etc.) */
2354         if (of_property_read_bool(nc, "spi-cpha"))
2355                 spi->mode |= SPI_CPHA;
2356         if (of_property_read_bool(nc, "spi-cpol"))
2357                 spi->mode |= SPI_CPOL;
2358         if (of_property_read_bool(nc, "spi-3wire"))
2359                 spi->mode |= SPI_3WIRE;
2360         if (of_property_read_bool(nc, "spi-lsb-first"))
2361                 spi->mode |= SPI_LSB_FIRST;
2362         if (of_property_read_bool(nc, "spi-cs-high"))
2363                 spi->mode |= SPI_CS_HIGH;
2364
2365         /* Device DUAL/QUAD mode */
2366         if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
2367                 switch (value) {
2368                 case 0:
2369                         spi->mode |= SPI_NO_TX;
2370                         break;
2371                 case 1:
2372                         break;
2373                 case 2:
2374                         spi->mode |= SPI_TX_DUAL;
2375                         break;
2376                 case 4:
2377                         spi->mode |= SPI_TX_QUAD;
2378                         break;
2379                 case 8:
2380                         spi->mode |= SPI_TX_OCTAL;
2381                         break;
2382                 default:
2383                         dev_warn(&ctlr->dev,
2384                                 "spi-tx-bus-width %d not supported\n",
2385                                 value);
2386                         break;
2387                 }
2388         }
2389
2390         if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
2391                 switch (value) {
2392                 case 0:
2393                         spi->mode |= SPI_NO_RX;
2394                         break;
2395                 case 1:
2396                         break;
2397                 case 2:
2398                         spi->mode |= SPI_RX_DUAL;
2399                         break;
2400                 case 4:
2401                         spi->mode |= SPI_RX_QUAD;
2402                         break;
2403                 case 8:
2404                         spi->mode |= SPI_RX_OCTAL;
2405                         break;
2406                 default:
2407                         dev_warn(&ctlr->dev,
2408                                 "spi-rx-bus-width %d not supported\n",
2409                                 value);
2410                         break;
2411                 }
2412         }
2413
2414         if (spi_controller_is_slave(ctlr)) {
2415                 if (!of_node_name_eq(nc, "slave")) {
2416                         dev_err(&ctlr->dev, "%pOF is not called 'slave'\n",
2417                                 nc);
2418                         return -EINVAL;
2419                 }
2420                 return 0;
2421         }
2422
2423         if (ctlr->num_chipselect > SPI_CS_CNT_MAX) {
2424                 dev_err(&ctlr->dev, "No. of CS is more than max. no. of supported CS\n");
2425                 return -EINVAL;
2426         }
2427
2428         /*
2429          * Zero(0) is a valid physical CS value and can be located at any
2430          * logical CS in the spi->chip_select[]. If all the physical CS
2431          * are initialized to 0 then It would be difficult to differentiate
2432          * between a valid physical CS 0 & an unused logical CS whose physical
2433          * CS can be 0. As a solution to this issue initialize all the CS to 0xFF.
2434          * Now all the unused logical CS will have 0xFF physical CS value & can be
2435          * ignore while performing physical CS validity checks.
2436          */
2437         for (idx = 0; idx < SPI_CS_CNT_MAX; idx++)
2438                 spi_set_chipselect(spi, idx, 0xFF);
2439
2440         /* Device address */
2441         rc = of_property_read_variable_u32_array(nc, "reg", &cs[0], 1,
2442                                                  SPI_CS_CNT_MAX);
2443         if (rc < 0) {
2444                 dev_err(&ctlr->dev, "%pOF has no valid 'reg' property (%d)\n",
2445                         nc, rc);
2446                 return rc;
2447         }
2448         if (rc > ctlr->num_chipselect) {
2449                 dev_err(&ctlr->dev, "%pOF has number of CS > ctlr->num_chipselect (%d)\n",
2450                         nc, rc);
2451                 return rc;
2452         }
2453         if ((of_property_read_bool(nc, "parallel-memories")) &&
2454             (!(ctlr->flags & SPI_CONTROLLER_MULTI_CS))) {
2455                 dev_err(&ctlr->dev, "SPI controller doesn't support multi CS\n");
2456                 return -EINVAL;
2457         }
2458         for (idx = 0; idx < rc; idx++)
2459                 spi_set_chipselect(spi, idx, cs[idx]);
2460
2461         /*
2462          * spi->chip_select[i] gives the corresponding physical CS for logical CS i
2463          * logical CS number is represented by setting the ith bit in spi->cs_index_mask
2464          * So, for example, if spi->cs_index_mask = 0x01 then logical CS number is 0 and
2465          * spi->chip_select[0] will give the physical CS.
2466          * By default spi->chip_select[0] will hold the physical CS number so, set
2467          * spi->cs_index_mask as 0x01.
2468          */
2469         spi->cs_index_mask = 0x01;
2470
2471         /* Device speed */
2472         if (!of_property_read_u32(nc, "spi-max-frequency", &value))
2473                 spi->max_speed_hz = value;
2474
2475         /* Device CS delays */
2476         of_spi_parse_dt_cs_delay(nc, &spi->cs_setup, "spi-cs-setup-delay-ns");
2477         of_spi_parse_dt_cs_delay(nc, &spi->cs_hold, "spi-cs-hold-delay-ns");
2478         of_spi_parse_dt_cs_delay(nc, &spi->cs_inactive, "spi-cs-inactive-delay-ns");
2479
2480         return 0;
2481 }
2482
2483 static struct spi_device *
2484 of_register_spi_device(struct spi_controller *ctlr, struct device_node *nc)
2485 {
2486         struct spi_device *spi;
2487         int rc;
2488
2489         /* Alloc an spi_device */
2490         spi = spi_alloc_device(ctlr);
2491         if (!spi) {
2492                 dev_err(&ctlr->dev, "spi_device alloc error for %pOF\n", nc);
2493                 rc = -ENOMEM;
2494                 goto err_out;
2495         }
2496
2497         /* Select device driver */
2498         rc = of_alias_from_compatible(nc, spi->modalias,
2499                                       sizeof(spi->modalias));
2500         if (rc < 0) {
2501                 dev_err(&ctlr->dev, "cannot find modalias for %pOF\n", nc);
2502                 goto err_out;
2503         }
2504
2505         rc = of_spi_parse_dt(ctlr, spi, nc);
2506         if (rc)
2507                 goto err_out;
2508
2509         /* Store a pointer to the node in the device structure */
2510         of_node_get(nc);
2511
2512         device_set_node(&spi->dev, of_fwnode_handle(nc));
2513
2514         /* Register the new device */
2515         rc = spi_add_device(spi);
2516         if (rc) {
2517                 dev_err(&ctlr->dev, "spi_device register error %pOF\n", nc);
2518                 goto err_of_node_put;
2519         }
2520
2521         return spi;
2522
2523 err_of_node_put:
2524         of_node_put(nc);
2525 err_out:
2526         spi_dev_put(spi);
2527         return ERR_PTR(rc);
2528 }
2529
2530 /**
2531  * of_register_spi_devices() - Register child devices onto the SPI bus
2532  * @ctlr:       Pointer to spi_controller device
2533  *
2534  * Registers an spi_device for each child node of controller node which
2535  * represents a valid SPI slave.
2536  */
2537 static void of_register_spi_devices(struct spi_controller *ctlr)
2538 {
2539         struct spi_device *spi;
2540         struct device_node *nc;
2541
2542         for_each_available_child_of_node(ctlr->dev.of_node, nc) {
2543                 if (of_node_test_and_set_flag(nc, OF_POPULATED))
2544                         continue;
2545                 spi = of_register_spi_device(ctlr, nc);
2546                 if (IS_ERR(spi)) {
2547                         dev_warn(&ctlr->dev,
2548                                  "Failed to create SPI device for %pOF\n", nc);
2549                         of_node_clear_flag(nc, OF_POPULATED);
2550                 }
2551         }
2552 }
2553 #else
2554 static void of_register_spi_devices(struct spi_controller *ctlr) { }
2555 #endif
2556
2557 /**
2558  * spi_new_ancillary_device() - Register ancillary SPI device
2559  * @spi:         Pointer to the main SPI device registering the ancillary device
2560  * @chip_select: Chip Select of the ancillary device
2561  *
2562  * Register an ancillary SPI device; for example some chips have a chip-select
2563  * for normal device usage and another one for setup/firmware upload.
2564  *
2565  * This may only be called from main SPI device's probe routine.
2566  *
2567  * Return: 0 on success; negative errno on failure
2568  */
2569 struct spi_device *spi_new_ancillary_device(struct spi_device *spi,
2570                                              u8 chip_select)
2571 {
2572         struct spi_controller *ctlr = spi->controller;
2573         struct spi_device *ancillary;
2574         int rc = 0;
2575         u8 idx;
2576
2577         /* Alloc an spi_device */
2578         ancillary = spi_alloc_device(ctlr);
2579         if (!ancillary) {
2580                 rc = -ENOMEM;
2581                 goto err_out;
2582         }
2583
2584         strscpy(ancillary->modalias, "dummy", sizeof(ancillary->modalias));
2585
2586         /*
2587          * Zero(0) is a valid physical CS value and can be located at any
2588          * logical CS in the spi->chip_select[]. If all the physical CS
2589          * are initialized to 0 then It would be difficult to differentiate
2590          * between a valid physical CS 0 & an unused logical CS whose physical
2591          * CS can be 0. As a solution to this issue initialize all the CS to 0xFF.
2592          * Now all the unused logical CS will have 0xFF physical CS value & can be
2593          * ignore while performing physical CS validity checks.
2594          */
2595         for (idx = 0; idx < SPI_CS_CNT_MAX; idx++)
2596                 spi_set_chipselect(ancillary, idx, 0xFF);
2597
2598         /* Use provided chip-select for ancillary device */
2599         spi_set_chipselect(ancillary, 0, chip_select);
2600
2601         /* Take over SPI mode/speed from SPI main device */
2602         ancillary->max_speed_hz = spi->max_speed_hz;
2603         ancillary->mode = spi->mode;
2604         /*
2605          * spi->chip_select[i] gives the corresponding physical CS for logical CS i
2606          * logical CS number is represented by setting the ith bit in spi->cs_index_mask
2607          * So, for example, if spi->cs_index_mask = 0x01 then logical CS number is 0 and
2608          * spi->chip_select[0] will give the physical CS.
2609          * By default spi->chip_select[0] will hold the physical CS number so, set
2610          * spi->cs_index_mask as 0x01.
2611          */
2612         ancillary->cs_index_mask = 0x01;
2613
2614         WARN_ON(!mutex_is_locked(&ctlr->add_lock));
2615
2616         /* Register the new device */
2617         rc = __spi_add_device(ancillary);
2618         if (rc) {
2619                 dev_err(&spi->dev, "failed to register ancillary device\n");
2620                 goto err_out;
2621         }
2622
2623         return ancillary;
2624
2625 err_out:
2626         spi_dev_put(ancillary);
2627         return ERR_PTR(rc);
2628 }
2629 EXPORT_SYMBOL_GPL(spi_new_ancillary_device);
2630
2631 #ifdef CONFIG_ACPI
2632 struct acpi_spi_lookup {
2633         struct spi_controller   *ctlr;
2634         u32                     max_speed_hz;
2635         u32                     mode;
2636         int                     irq;
2637         u8                      bits_per_word;
2638         u8                      chip_select;
2639         int                     n;
2640         int                     index;
2641 };
2642
2643 static int acpi_spi_count(struct acpi_resource *ares, void *data)
2644 {
2645         struct acpi_resource_spi_serialbus *sb;
2646         int *count = data;
2647
2648         if (ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
2649                 return 1;
2650
2651         sb = &ares->data.spi_serial_bus;
2652         if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_SPI)
2653                 return 1;
2654
2655         *count = *count + 1;
2656
2657         return 1;
2658 }
2659
2660 /**
2661  * acpi_spi_count_resources - Count the number of SpiSerialBus resources
2662  * @adev:       ACPI device
2663  *
2664  * Return: the number of SpiSerialBus resources in the ACPI-device's
2665  * resource-list; or a negative error code.
2666  */
2667 int acpi_spi_count_resources(struct acpi_device *adev)
2668 {
2669         LIST_HEAD(r);
2670         int count = 0;
2671         int ret;
2672
2673         ret = acpi_dev_get_resources(adev, &r, acpi_spi_count, &count);
2674         if (ret < 0)
2675                 return ret;
2676
2677         acpi_dev_free_resource_list(&r);
2678
2679         return count;
2680 }
2681 EXPORT_SYMBOL_GPL(acpi_spi_count_resources);
2682
2683 static void acpi_spi_parse_apple_properties(struct acpi_device *dev,
2684                                             struct acpi_spi_lookup *lookup)
2685 {
2686         const union acpi_object *obj;
2687
2688         if (!x86_apple_machine)
2689                 return;
2690
2691         if (!acpi_dev_get_property(dev, "spiSclkPeriod", ACPI_TYPE_BUFFER, &obj)
2692             && obj->buffer.length >= 4)
2693                 lookup->max_speed_hz  = NSEC_PER_SEC / *(u32 *)obj->buffer.pointer;
2694
2695         if (!acpi_dev_get_property(dev, "spiWordSize", ACPI_TYPE_BUFFER, &obj)
2696             && obj->buffer.length == 8)
2697                 lookup->bits_per_word = *(u64 *)obj->buffer.pointer;
2698
2699         if (!acpi_dev_get_property(dev, "spiBitOrder", ACPI_TYPE_BUFFER, &obj)
2700             && obj->buffer.length == 8 && !*(u64 *)obj->buffer.pointer)
2701                 lookup->mode |= SPI_LSB_FIRST;
2702
2703         if (!acpi_dev_get_property(dev, "spiSPO", ACPI_TYPE_BUFFER, &obj)
2704             && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
2705                 lookup->mode |= SPI_CPOL;
2706
2707         if (!acpi_dev_get_property(dev, "spiSPH", ACPI_TYPE_BUFFER, &obj)
2708             && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
2709                 lookup->mode |= SPI_CPHA;
2710 }
2711
2712 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
2713 {
2714         struct acpi_spi_lookup *lookup = data;
2715         struct spi_controller *ctlr = lookup->ctlr;
2716
2717         if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
2718                 struct acpi_resource_spi_serialbus *sb;
2719                 acpi_handle parent_handle;
2720                 acpi_status status;
2721
2722                 sb = &ares->data.spi_serial_bus;
2723                 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
2724
2725                         if (lookup->index != -1 && lookup->n++ != lookup->index)
2726                                 return 1;
2727
2728                         status = acpi_get_handle(NULL,
2729                                                  sb->resource_source.string_ptr,
2730                                                  &parent_handle);
2731
2732                         if (ACPI_FAILURE(status))
2733                                 return -ENODEV;
2734
2735                         if (ctlr) {
2736                                 if (ACPI_HANDLE(ctlr->dev.parent) != parent_handle)
2737                                         return -ENODEV;
2738                         } else {
2739                                 struct acpi_device *adev;
2740
2741                                 adev = acpi_fetch_acpi_dev(parent_handle);
2742                                 if (!adev)
2743                                         return -ENODEV;
2744
2745                                 ctlr = acpi_spi_find_controller_by_adev(adev);
2746                                 if (!ctlr)
2747                                         return -EPROBE_DEFER;
2748
2749                                 lookup->ctlr = ctlr;
2750                         }
2751
2752                         /*
2753                          * ACPI DeviceSelection numbering is handled by the
2754                          * host controller driver in Windows and can vary
2755                          * from driver to driver. In Linux we always expect
2756                          * 0 .. max - 1 so we need to ask the driver to
2757                          * translate between the two schemes.
2758                          */
2759                         if (ctlr->fw_translate_cs) {
2760                                 int cs = ctlr->fw_translate_cs(ctlr,
2761                                                 sb->device_selection);
2762                                 if (cs < 0)
2763                                         return cs;
2764                                 lookup->chip_select = cs;
2765                         } else {
2766                                 lookup->chip_select = sb->device_selection;
2767                         }
2768
2769                         lookup->max_speed_hz = sb->connection_speed;
2770                         lookup->bits_per_word = sb->data_bit_length;
2771
2772                         if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
2773                                 lookup->mode |= SPI_CPHA;
2774                         if (sb->clock_polarity == ACPI_SPI_START_HIGH)
2775                                 lookup->mode |= SPI_CPOL;
2776                         if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
2777                                 lookup->mode |= SPI_CS_HIGH;
2778                 }
2779         } else if (lookup->irq < 0) {
2780                 struct resource r;
2781
2782                 if (acpi_dev_resource_interrupt(ares, 0, &r))
2783                         lookup->irq = r.start;
2784         }
2785
2786         /* Always tell the ACPI core to skip this resource */
2787         return 1;
2788 }
2789
2790 /**
2791  * acpi_spi_device_alloc - Allocate a spi device, and fill it in with ACPI information
2792  * @ctlr: controller to which the spi device belongs
2793  * @adev: ACPI Device for the spi device
2794  * @index: Index of the spi resource inside the ACPI Node
2795  *
2796  * This should be used to allocate a new SPI device from and ACPI Device node.
2797  * The caller is responsible for calling spi_add_device to register the SPI device.
2798  *
2799  * If ctlr is set to NULL, the Controller for the SPI device will be looked up
2800  * using the resource.
2801  * If index is set to -1, index is not used.
2802  * Note: If index is -1, ctlr must be set.
2803  *
2804  * Return: a pointer to the new device, or ERR_PTR on error.
2805  */
2806 struct spi_device *acpi_spi_device_alloc(struct spi_controller *ctlr,
2807                                          struct acpi_device *adev,
2808                                          int index)
2809 {
2810         acpi_handle parent_handle = NULL;
2811         struct list_head resource_list;
2812         struct acpi_spi_lookup lookup = {};
2813         struct spi_device *spi;
2814         int ret;
2815         u8 idx;
2816
2817         if (!ctlr && index == -1)
2818                 return ERR_PTR(-EINVAL);
2819
2820         lookup.ctlr             = ctlr;
2821         lookup.irq              = -1;
2822         lookup.index            = index;
2823         lookup.n                = 0;
2824
2825         INIT_LIST_HEAD(&resource_list);
2826         ret = acpi_dev_get_resources(adev, &resource_list,
2827                                      acpi_spi_add_resource, &lookup);
2828         acpi_dev_free_resource_list(&resource_list);
2829
2830         if (ret < 0)
2831                 /* Found SPI in _CRS but it points to another controller */
2832                 return ERR_PTR(ret);
2833
2834         if (!lookup.max_speed_hz &&
2835             ACPI_SUCCESS(acpi_get_parent(adev->handle, &parent_handle)) &&
2836             ACPI_HANDLE(lookup.ctlr->dev.parent) == parent_handle) {
2837                 /* Apple does not use _CRS but nested devices for SPI slaves */
2838                 acpi_spi_parse_apple_properties(adev, &lookup);
2839         }
2840
2841         if (!lookup.max_speed_hz)
2842                 return ERR_PTR(-ENODEV);
2843
2844         spi = spi_alloc_device(lookup.ctlr);
2845         if (!spi) {
2846                 dev_err(&lookup.ctlr->dev, "failed to allocate SPI device for %s\n",
2847                         dev_name(&adev->dev));
2848                 return ERR_PTR(-ENOMEM);
2849         }
2850
2851         /*
2852          * Zero(0) is a valid physical CS value and can be located at any
2853          * logical CS in the spi->chip_select[]. If all the physical CS
2854          * are initialized to 0 then It would be difficult to differentiate
2855          * between a valid physical CS 0 & an unused logical CS whose physical
2856          * CS can be 0. As a solution to this issue initialize all the CS to 0xFF.
2857          * Now all the unused logical CS will have 0xFF physical CS value & can be
2858          * ignore while performing physical CS validity checks.
2859          */
2860         for (idx = 0; idx < SPI_CS_CNT_MAX; idx++)
2861                 spi_set_chipselect(spi, idx, 0xFF);
2862
2863         ACPI_COMPANION_SET(&spi->dev, adev);
2864         spi->max_speed_hz       = lookup.max_speed_hz;
2865         spi->mode               |= lookup.mode;
2866         spi->irq                = lookup.irq;
2867         spi->bits_per_word      = lookup.bits_per_word;
2868         spi_set_chipselect(spi, 0, lookup.chip_select);
2869         /*
2870          * spi->chip_select[i] gives the corresponding physical CS for logical CS i
2871          * logical CS number is represented by setting the ith bit in spi->cs_index_mask
2872          * So, for example, if spi->cs_index_mask = 0x01 then logical CS number is 0 and
2873          * spi->chip_select[0] will give the physical CS.
2874          * By default spi->chip_select[0] will hold the physical CS number so, set
2875          * spi->cs_index_mask as 0x01.
2876          */
2877         spi->cs_index_mask      = 0x01;
2878
2879         return spi;
2880 }
2881 EXPORT_SYMBOL_GPL(acpi_spi_device_alloc);
2882
2883 static acpi_status acpi_register_spi_device(struct spi_controller *ctlr,
2884                                             struct acpi_device *adev)
2885 {
2886         struct spi_device *spi;
2887
2888         if (acpi_bus_get_status(adev) || !adev->status.present ||
2889             acpi_device_enumerated(adev))
2890                 return AE_OK;
2891
2892         spi = acpi_spi_device_alloc(ctlr, adev, -1);
2893         if (IS_ERR(spi)) {
2894                 if (PTR_ERR(spi) == -ENOMEM)
2895                         return AE_NO_MEMORY;
2896                 else
2897                         return AE_OK;
2898         }
2899
2900         acpi_set_modalias(adev, acpi_device_hid(adev), spi->modalias,
2901                           sizeof(spi->modalias));
2902
2903         if (spi->irq < 0)
2904                 spi->irq = acpi_dev_gpio_irq_get(adev, 0);
2905
2906         acpi_device_set_enumerated(adev);
2907
2908         adev->power.flags.ignore_parent = true;
2909         if (spi_add_device(spi)) {
2910                 adev->power.flags.ignore_parent = false;
2911                 dev_err(&ctlr->dev, "failed to add SPI device %s from ACPI\n",
2912                         dev_name(&adev->dev));
2913                 spi_dev_put(spi);
2914         }
2915
2916         return AE_OK;
2917 }
2918
2919 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
2920                                        void *data, void **return_value)
2921 {
2922         struct acpi_device *adev = acpi_fetch_acpi_dev(handle);
2923         struct spi_controller *ctlr = data;
2924
2925         if (!adev)
2926                 return AE_OK;
2927
2928         return acpi_register_spi_device(ctlr, adev);
2929 }
2930
2931 #define SPI_ACPI_ENUMERATE_MAX_DEPTH            32
2932
2933 static void acpi_register_spi_devices(struct spi_controller *ctlr)
2934 {
2935         acpi_status status;
2936         acpi_handle handle;
2937
2938         handle = ACPI_HANDLE(ctlr->dev.parent);
2939         if (!handle)
2940                 return;
2941
2942         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
2943                                      SPI_ACPI_ENUMERATE_MAX_DEPTH,
2944                                      acpi_spi_add_device, NULL, ctlr, NULL);
2945         if (ACPI_FAILURE(status))
2946                 dev_warn(&ctlr->dev, "failed to enumerate SPI slaves\n");
2947 }
2948 #else
2949 static inline void acpi_register_spi_devices(struct spi_controller *ctlr) {}
2950 #endif /* CONFIG_ACPI */
2951
2952 static void spi_controller_release(struct device *dev)
2953 {
2954         struct spi_controller *ctlr;
2955
2956         ctlr = container_of(dev, struct spi_controller, dev);
2957         kfree(ctlr);
2958 }
2959
2960 static struct class spi_master_class = {
2961         .name           = "spi_master",
2962         .dev_release    = spi_controller_release,
2963         .dev_groups     = spi_master_groups,
2964 };
2965
2966 #ifdef CONFIG_SPI_SLAVE
2967 /**
2968  * spi_slave_abort - abort the ongoing transfer request on an SPI slave
2969  *                   controller
2970  * @spi: device used for the current transfer
2971  */
2972 int spi_slave_abort(struct spi_device *spi)
2973 {
2974         struct spi_controller *ctlr = spi->controller;
2975
2976         if (spi_controller_is_slave(ctlr) && ctlr->slave_abort)
2977                 return ctlr->slave_abort(ctlr);
2978
2979         return -ENOTSUPP;
2980 }
2981 EXPORT_SYMBOL_GPL(spi_slave_abort);
2982
2983 int spi_target_abort(struct spi_device *spi)
2984 {
2985         struct spi_controller *ctlr = spi->controller;
2986
2987         if (spi_controller_is_target(ctlr) && ctlr->target_abort)
2988                 return ctlr->target_abort(ctlr);
2989
2990         return -ENOTSUPP;
2991 }
2992 EXPORT_SYMBOL_GPL(spi_target_abort);
2993
2994 static ssize_t slave_show(struct device *dev, struct device_attribute *attr,
2995                           char *buf)
2996 {
2997         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2998                                                    dev);
2999         struct device *child;
3000
3001         child = device_find_any_child(&ctlr->dev);
3002         return sysfs_emit(buf, "%s\n", child ? to_spi_device(child)->modalias : NULL);
3003 }
3004
3005 static ssize_t slave_store(struct device *dev, struct device_attribute *attr,
3006                            const char *buf, size_t count)
3007 {
3008         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
3009                                                    dev);
3010         struct spi_device *spi;
3011         struct device *child;
3012         char name[32];
3013         int rc;
3014
3015         rc = sscanf(buf, "%31s", name);
3016         if (rc != 1 || !name[0])
3017                 return -EINVAL;
3018
3019         child = device_find_any_child(&ctlr->dev);
3020         if (child) {
3021                 /* Remove registered slave */
3022                 device_unregister(child);
3023                 put_device(child);
3024         }
3025
3026         if (strcmp(name, "(null)")) {
3027                 /* Register new slave */
3028                 spi = spi_alloc_device(ctlr);
3029                 if (!spi)
3030                         return -ENOMEM;
3031
3032                 strscpy(spi->modalias, name, sizeof(spi->modalias));
3033
3034                 rc = spi_add_device(spi);
3035                 if (rc) {
3036                         spi_dev_put(spi);
3037                         return rc;
3038                 }
3039         }
3040
3041         return count;
3042 }
3043
3044 static DEVICE_ATTR_RW(slave);
3045
3046 static struct attribute *spi_slave_attrs[] = {
3047         &dev_attr_slave.attr,
3048         NULL,
3049 };
3050
3051 static const struct attribute_group spi_slave_group = {
3052         .attrs = spi_slave_attrs,
3053 };
3054
3055 static const struct attribute_group *spi_slave_groups[] = {
3056         &spi_controller_statistics_group,
3057         &spi_slave_group,
3058         NULL,
3059 };
3060
3061 static struct class spi_slave_class = {
3062         .name           = "spi_slave",
3063         .dev_release    = spi_controller_release,
3064         .dev_groups     = spi_slave_groups,
3065 };
3066 #else
3067 extern struct class spi_slave_class;    /* dummy */
3068 #endif
3069
3070 /**
3071  * __spi_alloc_controller - allocate an SPI master or slave controller
3072  * @dev: the controller, possibly using the platform_bus
3073  * @size: how much zeroed driver-private data to allocate; the pointer to this
3074  *      memory is in the driver_data field of the returned device, accessible
3075  *      with spi_controller_get_devdata(); the memory is cacheline aligned;
3076  *      drivers granting DMA access to portions of their private data need to
3077  *      round up @size using ALIGN(size, dma_get_cache_alignment()).
3078  * @slave: flag indicating whether to allocate an SPI master (false) or SPI
3079  *      slave (true) controller
3080  * Context: can sleep
3081  *
3082  * This call is used only by SPI controller drivers, which are the
3083  * only ones directly touching chip registers.  It's how they allocate
3084  * an spi_controller structure, prior to calling spi_register_controller().
3085  *
3086  * This must be called from context that can sleep.
3087  *
3088  * The caller is responsible for assigning the bus number and initializing the
3089  * controller's methods before calling spi_register_controller(); and (after
3090  * errors adding the device) calling spi_controller_put() to prevent a memory
3091  * leak.
3092  *
3093  * Return: the SPI controller structure on success, else NULL.
3094  */
3095 struct spi_controller *__spi_alloc_controller(struct device *dev,
3096                                               unsigned int size, bool slave)
3097 {
3098         struct spi_controller   *ctlr;
3099         size_t ctlr_size = ALIGN(sizeof(*ctlr), dma_get_cache_alignment());
3100
3101         if (!dev)
3102                 return NULL;
3103
3104         ctlr = kzalloc(size + ctlr_size, GFP_KERNEL);
3105         if (!ctlr)
3106                 return NULL;
3107
3108         device_initialize(&ctlr->dev);
3109         INIT_LIST_HEAD(&ctlr->queue);
3110         spin_lock_init(&ctlr->queue_lock);
3111         spin_lock_init(&ctlr->bus_lock_spinlock);
3112         mutex_init(&ctlr->bus_lock_mutex);
3113         mutex_init(&ctlr->io_mutex);
3114         mutex_init(&ctlr->add_lock);
3115         ctlr->bus_num = -1;
3116         ctlr->num_chipselect = 1;
3117         ctlr->slave = slave;
3118         if (IS_ENABLED(CONFIG_SPI_SLAVE) && slave)
3119                 ctlr->dev.class = &spi_slave_class;
3120         else
3121                 ctlr->dev.class = &spi_master_class;
3122         ctlr->dev.parent = dev;
3123         pm_suspend_ignore_children(&ctlr->dev, true);
3124         spi_controller_set_devdata(ctlr, (void *)ctlr + ctlr_size);
3125
3126         return ctlr;
3127 }
3128 EXPORT_SYMBOL_GPL(__spi_alloc_controller);
3129
3130 static void devm_spi_release_controller(struct device *dev, void *ctlr)
3131 {
3132         spi_controller_put(*(struct spi_controller **)ctlr);
3133 }
3134
3135 /**
3136  * __devm_spi_alloc_controller - resource-managed __spi_alloc_controller()
3137  * @dev: physical device of SPI controller
3138  * @size: how much zeroed driver-private data to allocate
3139  * @slave: whether to allocate an SPI master (false) or SPI slave (true)
3140  * Context: can sleep
3141  *
3142  * Allocate an SPI controller and automatically release a reference on it
3143  * when @dev is unbound from its driver.  Drivers are thus relieved from
3144  * having to call spi_controller_put().
3145  *
3146  * The arguments to this function are identical to __spi_alloc_controller().
3147  *
3148  * Return: the SPI controller structure on success, else NULL.
3149  */
3150 struct spi_controller *__devm_spi_alloc_controller(struct device *dev,
3151                                                    unsigned int size,
3152                                                    bool slave)
3153 {
3154         struct spi_controller **ptr, *ctlr;
3155
3156         ptr = devres_alloc(devm_spi_release_controller, sizeof(*ptr),
3157                            GFP_KERNEL);
3158         if (!ptr)
3159                 return NULL;
3160
3161         ctlr = __spi_alloc_controller(dev, size, slave);
3162         if (ctlr) {
3163                 ctlr->devm_allocated = true;
3164                 *ptr = ctlr;
3165                 devres_add(dev, ptr);
3166         } else {
3167                 devres_free(ptr);
3168         }
3169
3170         return ctlr;
3171 }
3172 EXPORT_SYMBOL_GPL(__devm_spi_alloc_controller);
3173
3174 /**
3175  * spi_get_gpio_descs() - grab chip select GPIOs for the master
3176  * @ctlr: The SPI master to grab GPIO descriptors for
3177  */
3178 static int spi_get_gpio_descs(struct spi_controller *ctlr)
3179 {
3180         int nb, i;
3181         struct gpio_desc **cs;
3182         struct device *dev = &ctlr->dev;
3183         unsigned long native_cs_mask = 0;
3184         unsigned int num_cs_gpios = 0;
3185
3186         nb = gpiod_count(dev, "cs");
3187         if (nb < 0) {
3188                 /* No GPIOs at all is fine, else return the error */
3189                 if (nb == -ENOENT)
3190                         return 0;
3191                 return nb;
3192         }
3193
3194         ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
3195
3196         cs = devm_kcalloc(dev, ctlr->num_chipselect, sizeof(*cs),
3197                           GFP_KERNEL);
3198         if (!cs)
3199                 return -ENOMEM;
3200         ctlr->cs_gpiods = cs;
3201
3202         for (i = 0; i < nb; i++) {
3203                 /*
3204                  * Most chipselects are active low, the inverted
3205                  * semantics are handled by special quirks in gpiolib,
3206                  * so initializing them GPIOD_OUT_LOW here means
3207                  * "unasserted", in most cases this will drive the physical
3208                  * line high.
3209                  */
3210                 cs[i] = devm_gpiod_get_index_optional(dev, "cs", i,
3211                                                       GPIOD_OUT_LOW);
3212                 if (IS_ERR(cs[i]))
3213                         return PTR_ERR(cs[i]);
3214
3215                 if (cs[i]) {
3216                         /*
3217                          * If we find a CS GPIO, name it after the device and
3218                          * chip select line.
3219                          */
3220                         char *gpioname;
3221
3222                         gpioname = devm_kasprintf(dev, GFP_KERNEL, "%s CS%d",
3223                                                   dev_name(dev), i);
3224                         if (!gpioname)
3225                                 return -ENOMEM;
3226                         gpiod_set_consumer_name(cs[i], gpioname);
3227                         num_cs_gpios++;
3228                         continue;
3229                 }
3230
3231                 if (ctlr->max_native_cs && i >= ctlr->max_native_cs) {
3232                         dev_err(dev, "Invalid native chip select %d\n", i);
3233                         return -EINVAL;
3234                 }
3235                 native_cs_mask |= BIT(i);
3236         }
3237
3238         ctlr->unused_native_cs = ffs(~native_cs_mask) - 1;
3239
3240         if ((ctlr->flags & SPI_CONTROLLER_GPIO_SS) && num_cs_gpios &&
3241             ctlr->max_native_cs && ctlr->unused_native_cs >= ctlr->max_native_cs) {
3242                 dev_err(dev, "No unused native chip select available\n");
3243                 return -EINVAL;
3244         }
3245
3246         return 0;
3247 }
3248
3249 static int spi_controller_check_ops(struct spi_controller *ctlr)
3250 {
3251         /*
3252          * The controller may implement only the high-level SPI-memory like
3253          * operations if it does not support regular SPI transfers, and this is
3254          * valid use case.
3255          * If ->mem_ops or ->mem_ops->exec_op is NULL, we request that at least
3256          * one of the ->transfer_xxx() method be implemented.
3257          */
3258         if (!ctlr->mem_ops || !ctlr->mem_ops->exec_op) {
3259                 if (!ctlr->transfer && !ctlr->transfer_one &&
3260                    !ctlr->transfer_one_message) {
3261                         return -EINVAL;
3262                 }
3263         }
3264
3265         return 0;
3266 }
3267
3268 /* Allocate dynamic bus number using Linux idr */
3269 static int spi_controller_id_alloc(struct spi_controller *ctlr, int start, int end)
3270 {
3271         int id;
3272
3273         mutex_lock(&board_lock);
3274         id = idr_alloc(&spi_master_idr, ctlr, start, end, GFP_KERNEL);
3275         mutex_unlock(&board_lock);
3276         if (WARN(id < 0, "couldn't get idr"))
3277                 return id == -ENOSPC ? -EBUSY : id;
3278         ctlr->bus_num = id;
3279         return 0;
3280 }
3281
3282 /**
3283  * spi_register_controller - register SPI master or slave controller
3284  * @ctlr: initialized master, originally from spi_alloc_master() or
3285  *      spi_alloc_slave()
3286  * Context: can sleep
3287  *
3288  * SPI controllers connect to their drivers using some non-SPI bus,
3289  * such as the platform bus.  The final stage of probe() in that code
3290  * includes calling spi_register_controller() to hook up to this SPI bus glue.
3291  *
3292  * SPI controllers use board specific (often SOC specific) bus numbers,
3293  * and board-specific addressing for SPI devices combines those numbers
3294  * with chip select numbers.  Since SPI does not directly support dynamic
3295  * device identification, boards need configuration tables telling which
3296  * chip is at which address.
3297  *
3298  * This must be called from context that can sleep.  It returns zero on
3299  * success, else a negative error code (dropping the controller's refcount).
3300  * After a successful return, the caller is responsible for calling
3301  * spi_unregister_controller().
3302  *
3303  * Return: zero on success, else a negative error code.
3304  */
3305 int spi_register_controller(struct spi_controller *ctlr)
3306 {
3307         struct device           *dev = ctlr->dev.parent;
3308         struct boardinfo        *bi;
3309         int                     first_dynamic;
3310         int                     status;
3311         int                     idx;
3312
3313         if (!dev)
3314                 return -ENODEV;
3315
3316         /*
3317          * Make sure all necessary hooks are implemented before registering
3318          * the SPI controller.
3319          */
3320         status = spi_controller_check_ops(ctlr);
3321         if (status)
3322                 return status;
3323
3324         if (ctlr->bus_num < 0)
3325                 ctlr->bus_num = of_alias_get_id(ctlr->dev.of_node, "spi");
3326         if (ctlr->bus_num >= 0) {
3327                 /* Devices with a fixed bus num must check-in with the num */
3328                 status = spi_controller_id_alloc(ctlr, ctlr->bus_num, ctlr->bus_num + 1);
3329                 if (status)
3330                         return status;
3331         }
3332         if (ctlr->bus_num < 0) {
3333                 first_dynamic = of_alias_get_highest_id("spi");
3334                 if (first_dynamic < 0)
3335                         first_dynamic = 0;
3336                 else
3337                         first_dynamic++;
3338
3339                 status = spi_controller_id_alloc(ctlr, first_dynamic, 0);
3340                 if (status)
3341                         return status;
3342         }
3343         ctlr->bus_lock_flag = 0;
3344         init_completion(&ctlr->xfer_completion);
3345         init_completion(&ctlr->cur_msg_completion);
3346         if (!ctlr->max_dma_len)
3347                 ctlr->max_dma_len = INT_MAX;
3348
3349         /*
3350          * Register the device, then userspace will see it.
3351          * Registration fails if the bus ID is in use.
3352          */
3353         dev_set_name(&ctlr->dev, "spi%u", ctlr->bus_num);
3354
3355         if (!spi_controller_is_slave(ctlr) && ctlr->use_gpio_descriptors) {
3356                 status = spi_get_gpio_descs(ctlr);
3357                 if (status)
3358                         goto free_bus_id;
3359                 /*
3360                  * A controller using GPIO descriptors always
3361                  * supports SPI_CS_HIGH if need be.
3362                  */
3363                 ctlr->mode_bits |= SPI_CS_HIGH;
3364         }
3365
3366         /*
3367          * Even if it's just one always-selected device, there must
3368          * be at least one chipselect.
3369          */
3370         if (!ctlr->num_chipselect) {
3371                 status = -EINVAL;
3372                 goto free_bus_id;
3373         }
3374
3375         /* Setting last_cs to -1 means no chip selected */
3376         for (idx = 0; idx < SPI_CS_CNT_MAX; idx++)
3377                 ctlr->last_cs[idx] = -1;
3378
3379         status = device_add(&ctlr->dev);
3380         if (status < 0)
3381                 goto free_bus_id;
3382         dev_dbg(dev, "registered %s %s\n",
3383                         spi_controller_is_slave(ctlr) ? "slave" : "master",
3384                         dev_name(&ctlr->dev));
3385
3386         /*
3387          * If we're using a queued driver, start the queue. Note that we don't
3388          * need the queueing logic if the driver is only supporting high-level
3389          * memory operations.
3390          */
3391         if (ctlr->transfer) {
3392                 dev_info(dev, "controller is unqueued, this is deprecated\n");
3393         } else if (ctlr->transfer_one || ctlr->transfer_one_message) {
3394                 status = spi_controller_initialize_queue(ctlr);
3395                 if (status) {
3396                         device_del(&ctlr->dev);
3397                         goto free_bus_id;
3398                 }
3399         }
3400         /* Add statistics */
3401         ctlr->pcpu_statistics = spi_alloc_pcpu_stats(dev);
3402         if (!ctlr->pcpu_statistics) {
3403                 dev_err(dev, "Error allocating per-cpu statistics\n");
3404                 status = -ENOMEM;
3405                 goto destroy_queue;
3406         }
3407
3408         mutex_lock(&board_lock);
3409         list_add_tail(&ctlr->list, &spi_controller_list);
3410         list_for_each_entry(bi, &board_list, list)
3411                 spi_match_controller_to_boardinfo(ctlr, &bi->board_info);
3412         mutex_unlock(&board_lock);
3413
3414         /* Register devices from the device tree and ACPI */
3415         of_register_spi_devices(ctlr);
3416         acpi_register_spi_devices(ctlr);
3417         return status;
3418
3419 destroy_queue:
3420         spi_destroy_queue(ctlr);
3421 free_bus_id:
3422         mutex_lock(&board_lock);
3423         idr_remove(&spi_master_idr, ctlr->bus_num);
3424         mutex_unlock(&board_lock);
3425         return status;
3426 }
3427 EXPORT_SYMBOL_GPL(spi_register_controller);
3428
3429 static void devm_spi_unregister(struct device *dev, void *res)
3430 {
3431         spi_unregister_controller(*(struct spi_controller **)res);
3432 }
3433
3434 /**
3435  * devm_spi_register_controller - register managed SPI master or slave
3436  *      controller
3437  * @dev:    device managing SPI controller
3438  * @ctlr: initialized controller, originally from spi_alloc_master() or
3439  *      spi_alloc_slave()
3440  * Context: can sleep
3441  *
3442  * Register a SPI device as with spi_register_controller() which will
3443  * automatically be unregistered and freed.
3444  *
3445  * Return: zero on success, else a negative error code.
3446  */
3447 int devm_spi_register_controller(struct device *dev,
3448                                  struct spi_controller *ctlr)
3449 {
3450         struct spi_controller **ptr;
3451         int ret;
3452
3453         ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
3454         if (!ptr)
3455                 return -ENOMEM;
3456
3457         ret = spi_register_controller(ctlr);
3458         if (!ret) {
3459                 *ptr = ctlr;
3460                 devres_add(dev, ptr);
3461         } else {
3462                 devres_free(ptr);
3463         }
3464
3465         return ret;
3466 }
3467 EXPORT_SYMBOL_GPL(devm_spi_register_controller);
3468
3469 static int __unregister(struct device *dev, void *null)
3470 {
3471         spi_unregister_device(to_spi_device(dev));
3472         return 0;
3473 }
3474
3475 /**
3476  * spi_unregister_controller - unregister SPI master or slave controller
3477  * @ctlr: the controller being unregistered
3478  * Context: can sleep
3479  *
3480  * This call is used only by SPI controller drivers, which are the
3481  * only ones directly touching chip registers.
3482  *
3483  * This must be called from context that can sleep.
3484  *
3485  * Note that this function also drops a reference to the controller.
3486  */
3487 void spi_unregister_controller(struct spi_controller *ctlr)
3488 {
3489         struct spi_controller *found;
3490         int id = ctlr->bus_num;
3491
3492         /* Prevent addition of new devices, unregister existing ones */
3493         if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
3494                 mutex_lock(&ctlr->add_lock);
3495
3496         device_for_each_child(&ctlr->dev, NULL, __unregister);
3497
3498         /* First make sure that this controller was ever added */
3499         mutex_lock(&board_lock);
3500         found = idr_find(&spi_master_idr, id);
3501         mutex_unlock(&board_lock);
3502         if (ctlr->queued) {
3503                 if (spi_destroy_queue(ctlr))
3504                         dev_err(&ctlr->dev, "queue remove failed\n");
3505         }
3506         mutex_lock(&board_lock);
3507         list_del(&ctlr->list);
3508         mutex_unlock(&board_lock);
3509
3510         device_del(&ctlr->dev);
3511
3512         /* Free bus id */
3513         mutex_lock(&board_lock);
3514         if (found == ctlr)
3515                 idr_remove(&spi_master_idr, id);
3516         mutex_unlock(&board_lock);
3517
3518         if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
3519                 mutex_unlock(&ctlr->add_lock);
3520
3521         /*
3522          * Release the last reference on the controller if its driver
3523          * has not yet been converted to devm_spi_alloc_master/slave().
3524          */
3525         if (!ctlr->devm_allocated)
3526                 put_device(&ctlr->dev);
3527 }
3528 EXPORT_SYMBOL_GPL(spi_unregister_controller);
3529
3530 static inline int __spi_check_suspended(const struct spi_controller *ctlr)
3531 {
3532         return ctlr->flags & SPI_CONTROLLER_SUSPENDED ? -ESHUTDOWN : 0;
3533 }
3534
3535 static inline void __spi_mark_suspended(struct spi_controller *ctlr)
3536 {
3537         mutex_lock(&ctlr->bus_lock_mutex);
3538         ctlr->flags |= SPI_CONTROLLER_SUSPENDED;
3539         mutex_unlock(&ctlr->bus_lock_mutex);
3540 }
3541
3542 static inline void __spi_mark_resumed(struct spi_controller *ctlr)
3543 {
3544         mutex_lock(&ctlr->bus_lock_mutex);
3545         ctlr->flags &= ~SPI_CONTROLLER_SUSPENDED;
3546         mutex_unlock(&ctlr->bus_lock_mutex);
3547 }
3548
3549 int spi_controller_suspend(struct spi_controller *ctlr)
3550 {
3551         int ret = 0;
3552
3553         /* Basically no-ops for non-queued controllers */
3554         if (ctlr->queued) {
3555                 ret = spi_stop_queue(ctlr);
3556                 if (ret)
3557                         dev_err(&ctlr->dev, "queue stop failed\n");
3558         }
3559
3560         __spi_mark_suspended(ctlr);
3561         return ret;
3562 }
3563 EXPORT_SYMBOL_GPL(spi_controller_suspend);
3564
3565 int spi_controller_resume(struct spi_controller *ctlr)
3566 {
3567         int ret = 0;
3568
3569         __spi_mark_resumed(ctlr);
3570
3571         if (ctlr->queued) {
3572                 ret = spi_start_queue(ctlr);
3573                 if (ret)
3574                         dev_err(&ctlr->dev, "queue restart failed\n");
3575         }
3576         return ret;
3577 }
3578 EXPORT_SYMBOL_GPL(spi_controller_resume);
3579
3580 /*-------------------------------------------------------------------------*/
3581
3582 /* Core methods for spi_message alterations */
3583
3584 static void __spi_replace_transfers_release(struct spi_controller *ctlr,
3585                                             struct spi_message *msg,
3586                                             void *res)
3587 {
3588         struct spi_replaced_transfers *rxfer = res;
3589         size_t i;
3590
3591         /* Call extra callback if requested */
3592         if (rxfer->release)
3593                 rxfer->release(ctlr, msg, res);
3594
3595         /* Insert replaced transfers back into the message */
3596         list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
3597
3598         /* Remove the formerly inserted entries */
3599         for (i = 0; i < rxfer->inserted; i++)
3600                 list_del(&rxfer->inserted_transfers[i].transfer_list);
3601 }
3602
3603 /**
3604  * spi_replace_transfers - replace transfers with several transfers
3605  *                         and register change with spi_message.resources
3606  * @msg:           the spi_message we work upon
3607  * @xfer_first:    the first spi_transfer we want to replace
3608  * @remove:        number of transfers to remove
3609  * @insert:        the number of transfers we want to insert instead
3610  * @release:       extra release code necessary in some circumstances
3611  * @extradatasize: extra data to allocate (with alignment guarantees
3612  *                 of struct @spi_transfer)
3613  * @gfp:           gfp flags
3614  *
3615  * Returns: pointer to @spi_replaced_transfers,
3616  *          PTR_ERR(...) in case of errors.
3617  */
3618 static struct spi_replaced_transfers *spi_replace_transfers(
3619         struct spi_message *msg,
3620         struct spi_transfer *xfer_first,
3621         size_t remove,
3622         size_t insert,
3623         spi_replaced_release_t release,
3624         size_t extradatasize,
3625         gfp_t gfp)
3626 {
3627         struct spi_replaced_transfers *rxfer;
3628         struct spi_transfer *xfer;
3629         size_t i;
3630
3631         /* Allocate the structure using spi_res */
3632         rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
3633                               struct_size(rxfer, inserted_transfers, insert)
3634                               + extradatasize,
3635                               gfp);
3636         if (!rxfer)
3637                 return ERR_PTR(-ENOMEM);
3638
3639         /* The release code to invoke before running the generic release */
3640         rxfer->release = release;
3641
3642         /* Assign extradata */
3643         if (extradatasize)
3644                 rxfer->extradata =
3645                         &rxfer->inserted_transfers[insert];
3646
3647         /* Init the replaced_transfers list */
3648         INIT_LIST_HEAD(&rxfer->replaced_transfers);
3649
3650         /*
3651          * Assign the list_entry after which we should reinsert
3652          * the @replaced_transfers - it may be spi_message.messages!
3653          */
3654         rxfer->replaced_after = xfer_first->transfer_list.prev;
3655
3656         /* Remove the requested number of transfers */
3657         for (i = 0; i < remove; i++) {
3658                 /*
3659                  * If the entry after replaced_after it is msg->transfers
3660                  * then we have been requested to remove more transfers
3661                  * than are in the list.
3662                  */
3663                 if (rxfer->replaced_after->next == &msg->transfers) {
3664                         dev_err(&msg->spi->dev,
3665                                 "requested to remove more spi_transfers than are available\n");
3666                         /* Insert replaced transfers back into the message */
3667                         list_splice(&rxfer->replaced_transfers,
3668                                     rxfer->replaced_after);
3669
3670                         /* Free the spi_replace_transfer structure... */
3671                         spi_res_free(rxfer);
3672
3673                         /* ...and return with an error */
3674                         return ERR_PTR(-EINVAL);
3675                 }
3676
3677                 /*
3678                  * Remove the entry after replaced_after from list of
3679                  * transfers and add it to list of replaced_transfers.
3680                  */
3681                 list_move_tail(rxfer->replaced_after->next,
3682                                &rxfer->replaced_transfers);
3683         }
3684
3685         /*
3686          * Create copy of the given xfer with identical settings
3687          * based on the first transfer to get removed.
3688          */
3689         for (i = 0; i < insert; i++) {
3690                 /* We need to run in reverse order */
3691                 xfer = &rxfer->inserted_transfers[insert - 1 - i];
3692
3693                 /* Copy all spi_transfer data */
3694                 memcpy(xfer, xfer_first, sizeof(*xfer));
3695
3696                 /* Add to list */
3697                 list_add(&xfer->transfer_list, rxfer->replaced_after);
3698
3699                 /* Clear cs_change and delay for all but the last */
3700                 if (i) {
3701                         xfer->cs_change = false;
3702                         xfer->delay.value = 0;
3703                 }
3704         }
3705
3706         /* Set up inserted... */
3707         rxfer->inserted = insert;
3708
3709         /* ...and register it with spi_res/spi_message */
3710         spi_res_add(msg, rxfer);
3711
3712         return rxfer;
3713 }
3714
3715 static int __spi_split_transfer_maxsize(struct spi_controller *ctlr,
3716                                         struct spi_message *msg,
3717                                         struct spi_transfer **xferp,
3718                                         size_t maxsize,
3719                                         gfp_t gfp)
3720 {
3721         struct spi_transfer *xfer = *xferp, *xfers;
3722         struct spi_replaced_transfers *srt;
3723         size_t offset;
3724         size_t count, i;
3725
3726         /* Calculate how many we have to replace */
3727         count = DIV_ROUND_UP(xfer->len, maxsize);
3728
3729         /* Create replacement */
3730         srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
3731         if (IS_ERR(srt))
3732                 return PTR_ERR(srt);
3733         xfers = srt->inserted_transfers;
3734
3735         /*
3736          * Now handle each of those newly inserted spi_transfers.
3737          * Note that the replacements spi_transfers all are preset
3738          * to the same values as *xferp, so tx_buf, rx_buf and len
3739          * are all identical (as well as most others)
3740          * so we just have to fix up len and the pointers.
3741          *
3742          * This also includes support for the depreciated
3743          * spi_message.is_dma_mapped interface.
3744          */
3745
3746         /*
3747          * The first transfer just needs the length modified, so we
3748          * run it outside the loop.
3749          */
3750         xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
3751
3752         /* All the others need rx_buf/tx_buf also set */
3753         for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
3754                 /* Update rx_buf, tx_buf and DMA */
3755                 if (xfers[i].rx_buf)
3756                         xfers[i].rx_buf += offset;
3757                 if (xfers[i].rx_dma)
3758                         xfers[i].rx_dma += offset;
3759                 if (xfers[i].tx_buf)
3760                         xfers[i].tx_buf += offset;
3761                 if (xfers[i].tx_dma)
3762                         xfers[i].tx_dma += offset;
3763
3764                 /* Update length */
3765                 xfers[i].len = min(maxsize, xfers[i].len - offset);
3766         }
3767
3768         /*
3769          * We set up xferp to the last entry we have inserted,
3770          * so that we skip those already split transfers.
3771          */
3772         *xferp = &xfers[count - 1];
3773
3774         /* Increment statistics counters */
3775         SPI_STATISTICS_INCREMENT_FIELD(ctlr->pcpu_statistics,
3776                                        transfers_split_maxsize);
3777         SPI_STATISTICS_INCREMENT_FIELD(msg->spi->pcpu_statistics,
3778                                        transfers_split_maxsize);
3779
3780         return 0;
3781 }
3782
3783 /**
3784  * spi_split_transfers_maxsize - split spi transfers into multiple transfers
3785  *                               when an individual transfer exceeds a
3786  *                               certain size
3787  * @ctlr:    the @spi_controller for this transfer
3788  * @msg:   the @spi_message to transform
3789  * @maxsize:  the maximum when to apply this
3790  * @gfp: GFP allocation flags
3791  *
3792  * Return: status of transformation
3793  */
3794 int spi_split_transfers_maxsize(struct spi_controller *ctlr,
3795                                 struct spi_message *msg,
3796                                 size_t maxsize,
3797                                 gfp_t gfp)
3798 {
3799         struct spi_transfer *xfer;
3800         int ret;
3801
3802         /*
3803          * Iterate over the transfer_list,
3804          * but note that xfer is advanced to the last transfer inserted
3805          * to avoid checking sizes again unnecessarily (also xfer does
3806          * potentially belong to a different list by the time the
3807          * replacement has happened).
3808          */
3809         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
3810                 if (xfer->len > maxsize) {
3811                         ret = __spi_split_transfer_maxsize(ctlr, msg, &xfer,
3812                                                            maxsize, gfp);
3813                         if (ret)
3814                                 return ret;
3815                 }
3816         }
3817
3818         return 0;
3819 }
3820 EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
3821
3822
3823 /**
3824  * spi_split_transfers_maxwords - split SPI transfers into multiple transfers
3825  *                                when an individual transfer exceeds a
3826  *                                certain number of SPI words
3827  * @ctlr:     the @spi_controller for this transfer
3828  * @msg:      the @spi_message to transform
3829  * @maxwords: the number of words to limit each transfer to
3830  * @gfp:      GFP allocation flags
3831  *
3832  * Return: status of transformation
3833  */
3834 int spi_split_transfers_maxwords(struct spi_controller *ctlr,
3835                                  struct spi_message *msg,
3836                                  size_t maxwords,
3837                                  gfp_t gfp)
3838 {
3839         struct spi_transfer *xfer;
3840
3841         /*
3842          * Iterate over the transfer_list,
3843          * but note that xfer is advanced to the last transfer inserted
3844          * to avoid checking sizes again unnecessarily (also xfer does
3845          * potentially belong to a different list by the time the
3846          * replacement has happened).
3847          */
3848         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
3849                 size_t maxsize;
3850                 int ret;
3851
3852                 maxsize = maxwords * roundup_pow_of_two(BITS_TO_BYTES(xfer->bits_per_word));
3853                 if (xfer->len > maxsize) {
3854                         ret = __spi_split_transfer_maxsize(ctlr, msg, &xfer,
3855                                                            maxsize, gfp);
3856                         if (ret)
3857                                 return ret;
3858                 }
3859         }
3860
3861         return 0;
3862 }
3863 EXPORT_SYMBOL_GPL(spi_split_transfers_maxwords);
3864
3865 /*-------------------------------------------------------------------------*/
3866
3867 /*
3868  * Core methods for SPI controller protocol drivers. Some of the
3869  * other core methods are currently defined as inline functions.
3870  */
3871
3872 static int __spi_validate_bits_per_word(struct spi_controller *ctlr,
3873                                         u8 bits_per_word)
3874 {
3875         if (ctlr->bits_per_word_mask) {
3876                 /* Only 32 bits fit in the mask */
3877                 if (bits_per_word > 32)
3878                         return -EINVAL;
3879                 if (!(ctlr->bits_per_word_mask & SPI_BPW_MASK(bits_per_word)))
3880                         return -EINVAL;
3881         }
3882
3883         return 0;
3884 }
3885
3886 /**
3887  * spi_set_cs_timing - configure CS setup, hold, and inactive delays
3888  * @spi: the device that requires specific CS timing configuration
3889  *
3890  * Return: zero on success, else a negative error code.
3891  */
3892 static int spi_set_cs_timing(struct spi_device *spi)
3893 {
3894         struct device *parent = spi->controller->dev.parent;
3895         int status = 0;
3896
3897         if (spi->controller->set_cs_timing && !spi_get_csgpiod(spi, 0)) {
3898                 if (spi->controller->auto_runtime_pm) {
3899                         status = pm_runtime_get_sync(parent);
3900                         if (status < 0) {
3901                                 pm_runtime_put_noidle(parent);
3902                                 dev_err(&spi->controller->dev, "Failed to power device: %d\n",
3903                                         status);
3904                                 return status;
3905                         }
3906
3907                         status = spi->controller->set_cs_timing(spi);
3908                         pm_runtime_mark_last_busy(parent);
3909                         pm_runtime_put_autosuspend(parent);
3910                 } else {
3911                         status = spi->controller->set_cs_timing(spi);
3912                 }
3913         }
3914         return status;
3915 }
3916
3917 /**
3918  * spi_setup - setup SPI mode and clock rate
3919  * @spi: the device whose settings are being modified
3920  * Context: can sleep, and no requests are queued to the device
3921  *
3922  * SPI protocol drivers may need to update the transfer mode if the
3923  * device doesn't work with its default.  They may likewise need
3924  * to update clock rates or word sizes from initial values.  This function
3925  * changes those settings, and must be called from a context that can sleep.
3926  * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
3927  * effect the next time the device is selected and data is transferred to
3928  * or from it.  When this function returns, the SPI device is deselected.
3929  *
3930  * Note that this call will fail if the protocol driver specifies an option
3931  * that the underlying controller or its driver does not support.  For
3932  * example, not all hardware supports wire transfers using nine bit words,
3933  * LSB-first wire encoding, or active-high chipselects.
3934  *
3935  * Return: zero on success, else a negative error code.
3936  */
3937 int spi_setup(struct spi_device *spi)
3938 {
3939         unsigned        bad_bits, ugly_bits;
3940         int             status = 0;
3941
3942         /*
3943          * Check mode to prevent that any two of DUAL, QUAD and NO_MOSI/MISO
3944          * are set at the same time.
3945          */
3946         if ((hweight_long(spi->mode &
3947                 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_NO_TX)) > 1) ||
3948             (hweight_long(spi->mode &
3949                 (SPI_RX_DUAL | SPI_RX_QUAD | SPI_NO_RX)) > 1)) {
3950                 dev_err(&spi->dev,
3951                 "setup: can not select any two of dual, quad and no-rx/tx at the same time\n");
3952                 return -EINVAL;
3953         }
3954         /* If it is SPI_3WIRE mode, DUAL and QUAD should be forbidden */
3955         if ((spi->mode & SPI_3WIRE) && (spi->mode &
3956                 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
3957                  SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL)))
3958                 return -EINVAL;
3959         /*
3960          * Help drivers fail *cleanly* when they need options
3961          * that aren't supported with their current controller.
3962          * SPI_CS_WORD has a fallback software implementation,
3963          * so it is ignored here.
3964          */
3965         bad_bits = spi->mode & ~(spi->controller->mode_bits | SPI_CS_WORD |
3966                                  SPI_NO_TX | SPI_NO_RX);
3967         ugly_bits = bad_bits &
3968                     (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
3969                      SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL);
3970         if (ugly_bits) {
3971                 dev_warn(&spi->dev,
3972                          "setup: ignoring unsupported mode bits %x\n",
3973                          ugly_bits);
3974                 spi->mode &= ~ugly_bits;
3975                 bad_bits &= ~ugly_bits;
3976         }
3977         if (bad_bits) {
3978                 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
3979                         bad_bits);
3980                 return -EINVAL;
3981         }
3982
3983         if (!spi->bits_per_word) {
3984                 spi->bits_per_word = 8;
3985         } else {
3986                 /*
3987                  * Some controllers may not support the default 8 bits-per-word
3988                  * so only perform the check when this is explicitly provided.
3989                  */
3990                 status = __spi_validate_bits_per_word(spi->controller,
3991                                                       spi->bits_per_word);
3992                 if (status)
3993                         return status;
3994         }
3995
3996         if (spi->controller->max_speed_hz &&
3997             (!spi->max_speed_hz ||
3998              spi->max_speed_hz > spi->controller->max_speed_hz))
3999                 spi->max_speed_hz = spi->controller->max_speed_hz;
4000
4001         mutex_lock(&spi->controller->io_mutex);
4002
4003         if (spi->controller->setup) {
4004                 status = spi->controller->setup(spi);
4005                 if (status) {
4006                         mutex_unlock(&spi->controller->io_mutex);
4007                         dev_err(&spi->controller->dev, "Failed to setup device: %d\n",
4008                                 status);
4009                         return status;
4010                 }
4011         }
4012
4013         status = spi_set_cs_timing(spi);
4014         if (status) {
4015                 mutex_unlock(&spi->controller->io_mutex);
4016                 return status;
4017         }
4018
4019         if (spi->controller->auto_runtime_pm && spi->controller->set_cs) {
4020                 status = pm_runtime_resume_and_get(spi->controller->dev.parent);
4021                 if (status < 0) {
4022                         mutex_unlock(&spi->controller->io_mutex);
4023                         dev_err(&spi->controller->dev, "Failed to power device: %d\n",
4024                                 status);
4025                         return status;
4026                 }
4027
4028                 /*
4029                  * We do not want to return positive value from pm_runtime_get,
4030                  * there are many instances of devices calling spi_setup() and
4031                  * checking for a non-zero return value instead of a negative
4032                  * return value.
4033                  */
4034                 status = 0;
4035
4036                 spi_set_cs(spi, false, true);
4037                 pm_runtime_mark_last_busy(spi->controller->dev.parent);
4038                 pm_runtime_put_autosuspend(spi->controller->dev.parent);
4039         } else {
4040                 spi_set_cs(spi, false, true);
4041         }
4042
4043         mutex_unlock(&spi->controller->io_mutex);
4044
4045         if (spi->rt && !spi->controller->rt) {
4046                 spi->controller->rt = true;
4047                 spi_set_thread_rt(spi->controller);
4048         }
4049
4050         trace_spi_setup(spi, status);
4051
4052         dev_dbg(&spi->dev, "setup mode %lu, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
4053                         spi->mode & SPI_MODE_X_MASK,
4054                         (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
4055                         (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
4056                         (spi->mode & SPI_3WIRE) ? "3wire, " : "",
4057                         (spi->mode & SPI_LOOP) ? "loopback, " : "",
4058                         spi->bits_per_word, spi->max_speed_hz,
4059                         status);
4060
4061         return status;
4062 }
4063 EXPORT_SYMBOL_GPL(spi_setup);
4064
4065 static int _spi_xfer_word_delay_update(struct spi_transfer *xfer,
4066                                        struct spi_device *spi)
4067 {
4068         int delay1, delay2;
4069
4070         delay1 = spi_delay_to_ns(&xfer->word_delay, xfer);
4071         if (delay1 < 0)
4072                 return delay1;
4073
4074         delay2 = spi_delay_to_ns(&spi->word_delay, xfer);
4075         if (delay2 < 0)
4076                 return delay2;
4077
4078         if (delay1 < delay2)
4079                 memcpy(&xfer->word_delay, &spi->word_delay,
4080                        sizeof(xfer->word_delay));
4081
4082         return 0;
4083 }
4084
4085 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
4086 {
4087         struct spi_controller *ctlr = spi->controller;
4088         struct spi_transfer *xfer;
4089         int w_size;
4090
4091         if (list_empty(&message->transfers))
4092                 return -EINVAL;
4093
4094         message->spi = spi;
4095
4096         /*
4097          * Half-duplex links include original MicroWire, and ones with
4098          * only one data pin like SPI_3WIRE (switches direction) or where
4099          * either MOSI or MISO is missing.  They can also be caused by
4100          * software limitations.
4101          */
4102         if ((ctlr->flags & SPI_CONTROLLER_HALF_DUPLEX) ||
4103             (spi->mode & SPI_3WIRE)) {
4104                 unsigned flags = ctlr->flags;
4105
4106                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
4107                         if (xfer->rx_buf && xfer->tx_buf)
4108                                 return -EINVAL;
4109                         if ((flags & SPI_CONTROLLER_NO_TX) && xfer->tx_buf)
4110                                 return -EINVAL;
4111                         if ((flags & SPI_CONTROLLER_NO_RX) && xfer->rx_buf)
4112                                 return -EINVAL;
4113                 }
4114         }
4115
4116         /*
4117          * Set transfer bits_per_word and max speed as spi device default if
4118          * it is not set for this transfer.
4119          * Set transfer tx_nbits and rx_nbits as single transfer default
4120          * (SPI_NBITS_SINGLE) if it is not set for this transfer.
4121          * Ensure transfer word_delay is at least as long as that required by
4122          * device itself.
4123          */
4124         message->frame_length = 0;
4125         list_for_each_entry(xfer, &message->transfers, transfer_list) {
4126                 xfer->effective_speed_hz = 0;
4127                 message->frame_length += xfer->len;
4128                 if (!xfer->bits_per_word)
4129                         xfer->bits_per_word = spi->bits_per_word;
4130
4131                 if (!xfer->speed_hz)
4132                         xfer->speed_hz = spi->max_speed_hz;
4133
4134                 if (ctlr->max_speed_hz && xfer->speed_hz > ctlr->max_speed_hz)
4135                         xfer->speed_hz = ctlr->max_speed_hz;
4136
4137                 if (__spi_validate_bits_per_word(ctlr, xfer->bits_per_word))
4138                         return -EINVAL;
4139
4140                 /*
4141                  * SPI transfer length should be multiple of SPI word size
4142                  * where SPI word size should be power-of-two multiple.
4143                  */
4144                 if (xfer->bits_per_word <= 8)
4145                         w_size = 1;
4146                 else if (xfer->bits_per_word <= 16)
4147                         w_size = 2;
4148                 else
4149                         w_size = 4;
4150
4151                 /* No partial transfers accepted */
4152                 if (xfer->len % w_size)
4153                         return -EINVAL;
4154
4155                 if (xfer->speed_hz && ctlr->min_speed_hz &&
4156                     xfer->speed_hz < ctlr->min_speed_hz)
4157                         return -EINVAL;
4158
4159                 if (xfer->tx_buf && !xfer->tx_nbits)
4160                         xfer->tx_nbits = SPI_NBITS_SINGLE;
4161                 if (xfer->rx_buf && !xfer->rx_nbits)
4162                         xfer->rx_nbits = SPI_NBITS_SINGLE;
4163                 /*
4164                  * Check transfer tx/rx_nbits:
4165                  * 1. check the value matches one of single, dual and quad
4166                  * 2. check tx/rx_nbits match the mode in spi_device
4167                  */
4168                 if (xfer->tx_buf) {
4169                         if (spi->mode & SPI_NO_TX)
4170                                 return -EINVAL;
4171                         if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
4172                                 xfer->tx_nbits != SPI_NBITS_DUAL &&
4173                                 xfer->tx_nbits != SPI_NBITS_QUAD)
4174                                 return -EINVAL;
4175                         if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
4176                                 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
4177                                 return -EINVAL;
4178                         if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
4179                                 !(spi->mode & SPI_TX_QUAD))
4180                                 return -EINVAL;
4181                 }
4182                 /* Check transfer rx_nbits */
4183                 if (xfer->rx_buf) {
4184                         if (spi->mode & SPI_NO_RX)
4185                                 return -EINVAL;
4186                         if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
4187                                 xfer->rx_nbits != SPI_NBITS_DUAL &&
4188                                 xfer->rx_nbits != SPI_NBITS_QUAD)
4189                                 return -EINVAL;
4190                         if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
4191                                 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
4192                                 return -EINVAL;
4193                         if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
4194                                 !(spi->mode & SPI_RX_QUAD))
4195                                 return -EINVAL;
4196                 }
4197
4198                 if (_spi_xfer_word_delay_update(xfer, spi))
4199                         return -EINVAL;
4200         }
4201
4202         message->status = -EINPROGRESS;
4203
4204         return 0;
4205 }
4206
4207 static int __spi_async(struct spi_device *spi, struct spi_message *message)
4208 {
4209         struct spi_controller *ctlr = spi->controller;
4210         struct spi_transfer *xfer;
4211
4212         /*
4213          * Some controllers do not support doing regular SPI transfers. Return
4214          * ENOTSUPP when this is the case.
4215          */
4216         if (!ctlr->transfer)
4217                 return -ENOTSUPP;
4218
4219         SPI_STATISTICS_INCREMENT_FIELD(ctlr->pcpu_statistics, spi_async);
4220         SPI_STATISTICS_INCREMENT_FIELD(spi->pcpu_statistics, spi_async);
4221
4222         trace_spi_message_submit(message);
4223
4224         if (!ctlr->ptp_sts_supported) {
4225                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
4226                         xfer->ptp_sts_word_pre = 0;
4227                         ptp_read_system_prets(xfer->ptp_sts);
4228                 }
4229         }
4230
4231         return ctlr->transfer(spi, message);
4232 }
4233
4234 /**
4235  * spi_async - asynchronous SPI transfer
4236  * @spi: device with which data will be exchanged
4237  * @message: describes the data transfers, including completion callback
4238  * Context: any (IRQs may be blocked, etc)
4239  *
4240  * This call may be used in_irq and other contexts which can't sleep,
4241  * as well as from task contexts which can sleep.
4242  *
4243  * The completion callback is invoked in a context which can't sleep.
4244  * Before that invocation, the value of message->status is undefined.
4245  * When the callback is issued, message->status holds either zero (to
4246  * indicate complete success) or a negative error code.  After that
4247  * callback returns, the driver which issued the transfer request may
4248  * deallocate the associated memory; it's no longer in use by any SPI
4249  * core or controller driver code.
4250  *
4251  * Note that although all messages to a spi_device are handled in
4252  * FIFO order, messages may go to different devices in other orders.
4253  * Some device might be higher priority, or have various "hard" access
4254  * time requirements, for example.
4255  *
4256  * On detection of any fault during the transfer, processing of
4257  * the entire message is aborted, and the device is deselected.
4258  * Until returning from the associated message completion callback,
4259  * no other spi_message queued to that device will be processed.
4260  * (This rule applies equally to all the synchronous transfer calls,
4261  * which are wrappers around this core asynchronous primitive.)
4262  *
4263  * Return: zero on success, else a negative error code.
4264  */
4265 int spi_async(struct spi_device *spi, struct spi_message *message)
4266 {
4267         struct spi_controller *ctlr = spi->controller;
4268         int ret;
4269         unsigned long flags;
4270
4271         ret = __spi_validate(spi, message);
4272         if (ret != 0)
4273                 return ret;
4274
4275         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
4276
4277         if (ctlr->bus_lock_flag)
4278                 ret = -EBUSY;
4279         else
4280                 ret = __spi_async(spi, message);
4281
4282         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
4283
4284         return ret;
4285 }
4286 EXPORT_SYMBOL_GPL(spi_async);
4287
4288 /**
4289  * spi_async_locked - version of spi_async with exclusive bus usage
4290  * @spi: device with which data will be exchanged
4291  * @message: describes the data transfers, including completion callback
4292  * Context: any (IRQs may be blocked, etc)
4293  *
4294  * This call may be used in_irq and other contexts which can't sleep,
4295  * as well as from task contexts which can sleep.
4296  *
4297  * The completion callback is invoked in a context which can't sleep.
4298  * Before that invocation, the value of message->status is undefined.
4299  * When the callback is issued, message->status holds either zero (to
4300  * indicate complete success) or a negative error code.  After that
4301  * callback returns, the driver which issued the transfer request may
4302  * deallocate the associated memory; it's no longer in use by any SPI
4303  * core or controller driver code.
4304  *
4305  * Note that although all messages to a spi_device are handled in
4306  * FIFO order, messages may go to different devices in other orders.
4307  * Some device might be higher priority, or have various "hard" access
4308  * time requirements, for example.
4309  *
4310  * On detection of any fault during the transfer, processing of
4311  * the entire message is aborted, and the device is deselected.
4312  * Until returning from the associated message completion callback,
4313  * no other spi_message queued to that device will be processed.
4314  * (This rule applies equally to all the synchronous transfer calls,
4315  * which are wrappers around this core asynchronous primitive.)
4316  *
4317  * Return: zero on success, else a negative error code.
4318  */
4319 static int spi_async_locked(struct spi_device *spi, struct spi_message *message)
4320 {
4321         struct spi_controller *ctlr = spi->controller;
4322         int ret;
4323         unsigned long flags;
4324
4325         ret = __spi_validate(spi, message);
4326         if (ret != 0)
4327                 return ret;
4328
4329         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
4330
4331         ret = __spi_async(spi, message);
4332
4333         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
4334
4335         return ret;
4336
4337 }
4338
4339 static void __spi_transfer_message_noqueue(struct spi_controller *ctlr, struct spi_message *msg)
4340 {
4341         bool was_busy;
4342         int ret;
4343
4344         mutex_lock(&ctlr->io_mutex);
4345
4346         was_busy = ctlr->busy;
4347
4348         ctlr->cur_msg = msg;
4349         ret = __spi_pump_transfer_message(ctlr, msg, was_busy);
4350         if (ret)
4351                 dev_err(&ctlr->dev, "noqueue transfer failed\n");
4352         ctlr->cur_msg = NULL;
4353         ctlr->fallback = false;
4354
4355         if (!was_busy) {
4356                 kfree(ctlr->dummy_rx);
4357                 ctlr->dummy_rx = NULL;
4358                 kfree(ctlr->dummy_tx);
4359                 ctlr->dummy_tx = NULL;
4360                 if (ctlr->unprepare_transfer_hardware &&
4361                     ctlr->unprepare_transfer_hardware(ctlr))
4362                         dev_err(&ctlr->dev,
4363                                 "failed to unprepare transfer hardware\n");
4364                 spi_idle_runtime_pm(ctlr);
4365         }
4366
4367         mutex_unlock(&ctlr->io_mutex);
4368 }
4369
4370 /*-------------------------------------------------------------------------*/
4371
4372 /*
4373  * Utility methods for SPI protocol drivers, layered on
4374  * top of the core.  Some other utility methods are defined as
4375  * inline functions.
4376  */
4377
4378 static void spi_complete(void *arg)
4379 {
4380         complete(arg);
4381 }
4382
4383 static int __spi_sync(struct spi_device *spi, struct spi_message *message)
4384 {
4385         DECLARE_COMPLETION_ONSTACK(done);
4386         int status;
4387         struct spi_controller *ctlr = spi->controller;
4388
4389         if (__spi_check_suspended(ctlr)) {
4390                 dev_warn_once(&spi->dev, "Attempted to sync while suspend\n");
4391                 return -ESHUTDOWN;
4392         }
4393
4394         status = __spi_validate(spi, message);
4395         if (status != 0)
4396                 return status;
4397
4398         SPI_STATISTICS_INCREMENT_FIELD(ctlr->pcpu_statistics, spi_sync);
4399         SPI_STATISTICS_INCREMENT_FIELD(spi->pcpu_statistics, spi_sync);
4400
4401         /*
4402          * Checking queue_empty here only guarantees async/sync message
4403          * ordering when coming from the same context. It does not need to
4404          * guard against reentrancy from a different context. The io_mutex
4405          * will catch those cases.
4406          */
4407         if (READ_ONCE(ctlr->queue_empty) && !ctlr->must_async) {
4408                 message->actual_length = 0;
4409                 message->status = -EINPROGRESS;
4410
4411                 trace_spi_message_submit(message);
4412
4413                 SPI_STATISTICS_INCREMENT_FIELD(ctlr->pcpu_statistics, spi_sync_immediate);
4414                 SPI_STATISTICS_INCREMENT_FIELD(spi->pcpu_statistics, spi_sync_immediate);
4415
4416                 __spi_transfer_message_noqueue(ctlr, message);
4417
4418                 return message->status;
4419         }
4420
4421         /*
4422          * There are messages in the async queue that could have originated
4423          * from the same context, so we need to preserve ordering.
4424          * Therefor we send the message to the async queue and wait until they
4425          * are completed.
4426          */
4427         message->complete = spi_complete;
4428         message->context = &done;
4429         status = spi_async_locked(spi, message);
4430         if (status == 0) {
4431                 wait_for_completion(&done);
4432                 status = message->status;
4433         }
4434         message->context = NULL;
4435
4436         return status;
4437 }
4438
4439 /**
4440  * spi_sync - blocking/synchronous SPI data transfers
4441  * @spi: device with which data will be exchanged
4442  * @message: describes the data transfers
4443  * Context: can sleep
4444  *
4445  * This call may only be used from a context that may sleep.  The sleep
4446  * is non-interruptible, and has no timeout.  Low-overhead controller
4447  * drivers may DMA directly into and out of the message buffers.
4448  *
4449  * Note that the SPI device's chip select is active during the message,
4450  * and then is normally disabled between messages.  Drivers for some
4451  * frequently-used devices may want to minimize costs of selecting a chip,
4452  * by leaving it selected in anticipation that the next message will go
4453  * to the same chip.  (That may increase power usage.)
4454  *
4455  * Also, the caller is guaranteeing that the memory associated with the
4456  * message will not be freed before this call returns.
4457  *
4458  * Return: zero on success, else a negative error code.
4459  */
4460 int spi_sync(struct spi_device *spi, struct spi_message *message)
4461 {
4462         int ret;
4463
4464         mutex_lock(&spi->controller->bus_lock_mutex);
4465         ret = __spi_sync(spi, message);
4466         mutex_unlock(&spi->controller->bus_lock_mutex);
4467
4468         return ret;
4469 }
4470 EXPORT_SYMBOL_GPL(spi_sync);
4471
4472 /**
4473  * spi_sync_locked - version of spi_sync with exclusive bus usage
4474  * @spi: device with which data will be exchanged
4475  * @message: describes the data transfers
4476  * Context: can sleep
4477  *
4478  * This call may only be used from a context that may sleep.  The sleep
4479  * is non-interruptible, and has no timeout.  Low-overhead controller
4480  * drivers may DMA directly into and out of the message buffers.
4481  *
4482  * This call should be used by drivers that require exclusive access to the
4483  * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
4484  * be released by a spi_bus_unlock call when the exclusive access is over.
4485  *
4486  * Return: zero on success, else a negative error code.
4487  */
4488 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
4489 {
4490         return __spi_sync(spi, message);
4491 }
4492 EXPORT_SYMBOL_GPL(spi_sync_locked);
4493
4494 /**
4495  * spi_bus_lock - obtain a lock for exclusive SPI bus usage
4496  * @ctlr: SPI bus master that should be locked for exclusive bus access
4497  * Context: can sleep
4498  *
4499  * This call may only be used from a context that may sleep.  The sleep
4500  * is non-interruptible, and has no timeout.
4501  *
4502  * This call should be used by drivers that require exclusive access to the
4503  * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
4504  * exclusive access is over. Data transfer must be done by spi_sync_locked
4505  * and spi_async_locked calls when the SPI bus lock is held.
4506  *
4507  * Return: always zero.
4508  */
4509 int spi_bus_lock(struct spi_controller *ctlr)
4510 {
4511         unsigned long flags;
4512
4513         mutex_lock(&ctlr->bus_lock_mutex);
4514
4515         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
4516         ctlr->bus_lock_flag = 1;
4517         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
4518
4519         /* Mutex remains locked until spi_bus_unlock() is called */
4520
4521         return 0;
4522 }
4523 EXPORT_SYMBOL_GPL(spi_bus_lock);
4524
4525 /**
4526  * spi_bus_unlock - release the lock for exclusive SPI bus usage
4527  * @ctlr: SPI bus master that was locked for exclusive bus access
4528  * Context: can sleep
4529  *
4530  * This call may only be used from a context that may sleep.  The sleep
4531  * is non-interruptible, and has no timeout.
4532  *
4533  * This call releases an SPI bus lock previously obtained by an spi_bus_lock
4534  * call.
4535  *
4536  * Return: always zero.
4537  */
4538 int spi_bus_unlock(struct spi_controller *ctlr)
4539 {
4540         ctlr->bus_lock_flag = 0;
4541
4542         mutex_unlock(&ctlr->bus_lock_mutex);
4543
4544         return 0;
4545 }
4546 EXPORT_SYMBOL_GPL(spi_bus_unlock);
4547
4548 /* Portable code must never pass more than 32 bytes */
4549 #define SPI_BUFSIZ      max(32, SMP_CACHE_BYTES)
4550
4551 static u8       *buf;
4552
4553 /**
4554  * spi_write_then_read - SPI synchronous write followed by read
4555  * @spi: device with which data will be exchanged
4556  * @txbuf: data to be written (need not be DMA-safe)
4557  * @n_tx: size of txbuf, in bytes
4558  * @rxbuf: buffer into which data will be read (need not be DMA-safe)
4559  * @n_rx: size of rxbuf, in bytes
4560  * Context: can sleep
4561  *
4562  * This performs a half duplex MicroWire style transaction with the
4563  * device, sending txbuf and then reading rxbuf.  The return value
4564  * is zero for success, else a negative errno status code.
4565  * This call may only be used from a context that may sleep.
4566  *
4567  * Parameters to this routine are always copied using a small buffer.
4568  * Performance-sensitive or bulk transfer code should instead use
4569  * spi_{async,sync}() calls with DMA-safe buffers.
4570  *
4571  * Return: zero on success, else a negative error code.
4572  */
4573 int spi_write_then_read(struct spi_device *spi,
4574                 const void *txbuf, unsigned n_tx,
4575                 void *rxbuf, unsigned n_rx)
4576 {
4577         static DEFINE_MUTEX(lock);
4578
4579         int                     status;
4580         struct spi_message      message;
4581         struct spi_transfer     x[2];
4582         u8                      *local_buf;
4583
4584         /*
4585          * Use preallocated DMA-safe buffer if we can. We can't avoid
4586          * copying here, (as a pure convenience thing), but we can
4587          * keep heap costs out of the hot path unless someone else is
4588          * using the pre-allocated buffer or the transfer is too large.
4589          */
4590         if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
4591                 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
4592                                     GFP_KERNEL | GFP_DMA);
4593                 if (!local_buf)
4594                         return -ENOMEM;
4595         } else {
4596                 local_buf = buf;
4597         }
4598
4599         spi_message_init(&message);
4600         memset(x, 0, sizeof(x));
4601         if (n_tx) {
4602                 x[0].len = n_tx;
4603                 spi_message_add_tail(&x[0], &message);
4604         }
4605         if (n_rx) {
4606                 x[1].len = n_rx;
4607                 spi_message_add_tail(&x[1], &message);
4608         }
4609
4610         memcpy(local_buf, txbuf, n_tx);
4611         x[0].tx_buf = local_buf;
4612         x[1].rx_buf = local_buf + n_tx;
4613
4614         /* Do the I/O */
4615         status = spi_sync(spi, &message);
4616         if (status == 0)
4617                 memcpy(rxbuf, x[1].rx_buf, n_rx);
4618
4619         if (x[0].tx_buf == buf)
4620                 mutex_unlock(&lock);
4621         else
4622                 kfree(local_buf);
4623
4624         return status;
4625 }
4626 EXPORT_SYMBOL_GPL(spi_write_then_read);
4627
4628 /*-------------------------------------------------------------------------*/
4629
4630 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
4631 /* Must call put_device() when done with returned spi_device device */
4632 static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
4633 {
4634         struct device *dev = bus_find_device_by_of_node(&spi_bus_type, node);
4635
4636         return dev ? to_spi_device(dev) : NULL;
4637 }
4638
4639 /* The spi controllers are not using spi_bus, so we find it with another way */
4640 static struct spi_controller *of_find_spi_controller_by_node(struct device_node *node)
4641 {
4642         struct device *dev;
4643
4644         dev = class_find_device_by_of_node(&spi_master_class, node);
4645         if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
4646                 dev = class_find_device_by_of_node(&spi_slave_class, node);
4647         if (!dev)
4648                 return NULL;
4649
4650         /* Reference got in class_find_device */
4651         return container_of(dev, struct spi_controller, dev);
4652 }
4653
4654 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
4655                          void *arg)
4656 {
4657         struct of_reconfig_data *rd = arg;
4658         struct spi_controller *ctlr;
4659         struct spi_device *spi;
4660
4661         switch (of_reconfig_get_state_change(action, arg)) {
4662         case OF_RECONFIG_CHANGE_ADD:
4663                 ctlr = of_find_spi_controller_by_node(rd->dn->parent);
4664                 if (ctlr == NULL)
4665                         return NOTIFY_OK;       /* Not for us */
4666
4667                 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
4668                         put_device(&ctlr->dev);
4669                         return NOTIFY_OK;
4670                 }
4671
4672                 /*
4673                  * Clear the flag before adding the device so that fw_devlink
4674                  * doesn't skip adding consumers to this device.
4675                  */
4676                 rd->dn->fwnode.flags &= ~FWNODE_FLAG_NOT_DEVICE;
4677                 spi = of_register_spi_device(ctlr, rd->dn);
4678                 put_device(&ctlr->dev);
4679
4680                 if (IS_ERR(spi)) {
4681                         pr_err("%s: failed to create for '%pOF'\n",
4682                                         __func__, rd->dn);
4683                         of_node_clear_flag(rd->dn, OF_POPULATED);
4684                         return notifier_from_errno(PTR_ERR(spi));
4685                 }
4686                 break;
4687
4688         case OF_RECONFIG_CHANGE_REMOVE:
4689                 /* Already depopulated? */
4690                 if (!of_node_check_flag(rd->dn, OF_POPULATED))
4691                         return NOTIFY_OK;
4692
4693                 /* Find our device by node */
4694                 spi = of_find_spi_device_by_node(rd->dn);
4695                 if (spi == NULL)
4696                         return NOTIFY_OK;       /* No? not meant for us */
4697
4698                 /* Unregister takes one ref away */
4699                 spi_unregister_device(spi);
4700
4701                 /* And put the reference of the find */
4702                 put_device(&spi->dev);
4703                 break;
4704         }
4705
4706         return NOTIFY_OK;
4707 }
4708
4709 static struct notifier_block spi_of_notifier = {
4710         .notifier_call = of_spi_notify,
4711 };
4712 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
4713 extern struct notifier_block spi_of_notifier;
4714 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
4715
4716 #if IS_ENABLED(CONFIG_ACPI)
4717 static int spi_acpi_controller_match(struct device *dev, const void *data)
4718 {
4719         return ACPI_COMPANION(dev->parent) == data;
4720 }
4721
4722 struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev)
4723 {
4724         struct device *dev;
4725
4726         dev = class_find_device(&spi_master_class, NULL, adev,
4727                                 spi_acpi_controller_match);
4728         if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
4729                 dev = class_find_device(&spi_slave_class, NULL, adev,
4730                                         spi_acpi_controller_match);
4731         if (!dev)
4732                 return NULL;
4733
4734         return container_of(dev, struct spi_controller, dev);
4735 }
4736 EXPORT_SYMBOL_GPL(acpi_spi_find_controller_by_adev);
4737
4738 static struct spi_device *acpi_spi_find_device_by_adev(struct acpi_device *adev)
4739 {
4740         struct device *dev;
4741
4742         dev = bus_find_device_by_acpi_dev(&spi_bus_type, adev);
4743         return to_spi_device(dev);
4744 }
4745
4746 static int acpi_spi_notify(struct notifier_block *nb, unsigned long value,
4747                            void *arg)
4748 {
4749         struct acpi_device *adev = arg;
4750         struct spi_controller *ctlr;
4751         struct spi_device *spi;
4752
4753         switch (value) {
4754         case ACPI_RECONFIG_DEVICE_ADD:
4755                 ctlr = acpi_spi_find_controller_by_adev(acpi_dev_parent(adev));
4756                 if (!ctlr)
4757                         break;
4758
4759                 acpi_register_spi_device(ctlr, adev);
4760                 put_device(&ctlr->dev);
4761                 break;
4762         case ACPI_RECONFIG_DEVICE_REMOVE:
4763                 if (!acpi_device_enumerated(adev))
4764                         break;
4765
4766                 spi = acpi_spi_find_device_by_adev(adev);
4767                 if (!spi)
4768                         break;
4769
4770                 spi_unregister_device(spi);
4771                 put_device(&spi->dev);
4772                 break;
4773         }
4774
4775         return NOTIFY_OK;
4776 }
4777
4778 static struct notifier_block spi_acpi_notifier = {
4779         .notifier_call = acpi_spi_notify,
4780 };
4781 #else
4782 extern struct notifier_block spi_acpi_notifier;
4783 #endif
4784
4785 static int __init spi_init(void)
4786 {
4787         int     status;
4788
4789         buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
4790         if (!buf) {
4791                 status = -ENOMEM;
4792                 goto err0;
4793         }
4794
4795         status = bus_register(&spi_bus_type);
4796         if (status < 0)
4797                 goto err1;
4798
4799         status = class_register(&spi_master_class);
4800         if (status < 0)
4801                 goto err2;
4802
4803         if (IS_ENABLED(CONFIG_SPI_SLAVE)) {
4804                 status = class_register(&spi_slave_class);
4805                 if (status < 0)
4806                         goto err3;
4807         }
4808
4809         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
4810                 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
4811         if (IS_ENABLED(CONFIG_ACPI))
4812                 WARN_ON(acpi_reconfig_notifier_register(&spi_acpi_notifier));
4813
4814         return 0;
4815
4816 err3:
4817         class_unregister(&spi_master_class);
4818 err2:
4819         bus_unregister(&spi_bus_type);
4820 err1:
4821         kfree(buf);
4822         buf = NULL;
4823 err0:
4824         return status;
4825 }
4826
4827 /*
4828  * A board_info is normally registered in arch_initcall(),
4829  * but even essential drivers wait till later.
4830  *
4831  * REVISIT only boardinfo really needs static linking. The rest (device and
4832  * driver registration) _could_ be dynamically linked (modular) ... Costs
4833  * include needing to have boardinfo data structures be much more public.
4834  */
4835 postcore_initcall(spi_init);