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/kernel.h>
   8 #include <linux/device.h>
   9 #include <linux/init.h>
  10 #include <linux/cache.h>
  11 #include <linux/dma-mapping.h>
  12 #include <linux/dmaengine.h>
  13 #include <linux/mutex.h>
  14 #include <linux/of_device.h>
  15 #include <linux/of_irq.h>
  16 #include <linux/clk/clk-conf.h>
  17 #include <linux/slab.h>
  18 #include <linux/mod_devicetable.h>
  19 #include <linux/spi/spi.h>
  20 #include <linux/spi/spi-mem.h>
  21 #include <linux/of_gpio.h>
  22 #include <linux/gpio/consumer.h>
  23 #include <linux/pm_runtime.h>
  24 #include <linux/pm_domain.h>
  25 #include <linux/property.h>
  26 #include <linux/export.h>
  27 #include <linux/sched/rt.h>
  28 #include <uapi/linux/sched/types.h>
  29 #include <linux/delay.h>
  30 #include <linux/kthread.h>
  31 #include <linux/ioport.h>
  32 #include <linux/acpi.h>
  33 #include <linux/highmem.h>
  34 #include <linux/idr.h>
  35 #include <linux/platform_data/x86/apple.h>
  36
  37 #define CREATE_TRACE_POINTS
  38 #include <trace/events/spi.h>
  39 EXPORT_TRACEPOINT_SYMBOL(spi_transfer_start);
  40 EXPORT_TRACEPOINT_SYMBOL(spi_transfer_stop);
  41
  42 #include "internals.h"
  43
  44 static DEFINE_IDR(spi_master_idr);
  45
  46 static void spidev_release(struct device *dev)
  47 {
  48         struct spi_device       *spi = to_spi_device(dev);
  49
  50         spi_controller_put(spi->controller);
  51         kfree(spi->driver_override);
  52         kfree(spi);
  53 }
  54
  55 static ssize_t
  56 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
  57 {
  58         const struct spi_device *spi = to_spi_device(dev);
  59         int len;
  60
  61         len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
  62         if (len != -ENODEV)
  63                 return len;
  64
  65         return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
  66 }
  67 static DEVICE_ATTR_RO(modalias);
  68
  69 static ssize_t driver_override_store(struct device *dev,
  70                                      struct device_attribute *a,
  71                                      const char *buf, size_t count)
  72 {
  73         struct spi_device *spi = to_spi_device(dev);
  74         const char *end = memchr(buf, '\n', count);
  75         const size_t len = end ? end - buf : count;
  76         const char *driver_override, *old;
  77
  78         /* We need to keep extra room for a newline when displaying value */
  79         if (len >= (PAGE_SIZE - 1))
  80                 return -EINVAL;
  81
  82         driver_override = kstrndup(buf, len, GFP_KERNEL);
  83         if (!driver_override)
  84                 return -ENOMEM;
  85
  86         device_lock(dev);
  87         old = spi->driver_override;
  88         if (len) {
  89                 spi->driver_override = driver_override;
  90         } else {
  91                 /* Empty string, disable driver override */
  92                 spi->driver_override = NULL;
  93                 kfree(driver_override);
  94         }
  95         device_unlock(dev);
  96         kfree(old);
  97
  98         return count;
  99 }
 100
 101 static ssize_t driver_override_show(struct device *dev,
 102                                     struct device_attribute *a, char *buf)
 103 {
 104         const struct spi_device *spi = to_spi_device(dev);
 105         ssize_t len;
 106
 107         device_lock(dev);
 108         len = snprintf(buf, PAGE_SIZE, "%s\n", spi->driver_override ? : "");
 109         device_unlock(dev);
 110         return len;
 111 }
 112 static DEVICE_ATTR_RW(driver_override);
 113
 114 #define SPI_STATISTICS_ATTRS(field, file)                               \
 115 static ssize_t spi_controller_##field##_show(struct device *dev,        \
 116                                              struct device_attribute *attr, \
 117                                              char *buf)                 \
 118 {                                                                       \
 119         struct spi_controller *ctlr = container_of(dev,                 \
 120                                          struct spi_controller, dev);   \
 121         return spi_statistics_##field##_show(&ctlr->statistics, buf);   \
 122 }                                                                       \
 123 static struct device_attribute dev_attr_spi_controller_##field = {      \
 124         .attr = { .name = file, .mode = 0444 },                         \
 125         .show = spi_controller_##field##_show,                          \
 126 };                                                                      \
 127 static ssize_t spi_device_##field##_show(struct device *dev,            \
 128                                          struct device_attribute *attr, \
 129                                         char *buf)                      \
 130 {                                                                       \
 131         struct spi_device *spi = to_spi_device(dev);                    \
 132         return spi_statistics_##field##_show(&spi->statistics, buf);    \
 133 }                                                                       \
 134 static struct device_attribute dev_attr_spi_device_##field = {          \
 135         .attr = { .name = file, .mode = 0444 },                         \
 136         .show = spi_device_##field##_show,                              \
 137 }
 138
 139 #define SPI_STATISTICS_SHOW_NAME(name, file, field, format_string)      \
 140 static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
 141                                             char *buf)                  \
 142 {                                                                       \
 143         unsigned long flags;                                            \
 144         ssize_t len;                                                    \
 145         spin_lock_irqsave(&stat->lock, flags);                          \
 146         len = sprintf(buf, format_string, stat->field);                 \
 147         spin_unlock_irqrestore(&stat->lock, flags);                     \
 148         return len;                                                     \
 149 }                                                                       \
 150 SPI_STATISTICS_ATTRS(name, file)
 151
 152 #define SPI_STATISTICS_SHOW(field, format_string)                       \
 153         SPI_STATISTICS_SHOW_NAME(field, __stringify(field),             \
 154                                  field, format_string)
 155
 156 SPI_STATISTICS_SHOW(messages, "%lu");
 157 SPI_STATISTICS_SHOW(transfers, "%lu");
 158 SPI_STATISTICS_SHOW(errors, "%lu");
 159 SPI_STATISTICS_SHOW(timedout, "%lu");
 160
 161 SPI_STATISTICS_SHOW(spi_sync, "%lu");
 162 SPI_STATISTICS_SHOW(spi_sync_immediate, "%lu");
 163 SPI_STATISTICS_SHOW(spi_async, "%lu");
 164
 165 SPI_STATISTICS_SHOW(bytes, "%llu");
 166 SPI_STATISTICS_SHOW(bytes_rx, "%llu");
 167 SPI_STATISTICS_SHOW(bytes_tx, "%llu");
 168
 169 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number)              \
 170         SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index,           \
 171                                  "transfer_bytes_histo_" number,        \
 172                                  transfer_bytes_histo[index],  "%lu")
 173 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0,  "0-1");
 174 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1,  "2-3");
 175 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2,  "4-7");
 176 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3,  "8-15");
 177 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4,  "16-31");
 178 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5,  "32-63");
 179 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6,  "64-127");
 180 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7,  "128-255");
 181 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8,  "256-511");
 182 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9,  "512-1023");
 183 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
 184 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
 185 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
 186 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
 187 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
 188 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
 189 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
 190
 191 SPI_STATISTICS_SHOW(transfers_split_maxsize, "%lu");
 192
 193 static struct attribute *spi_dev_attrs[] = {
 194         &dev_attr_modalias.attr,
 195         &dev_attr_driver_override.attr,
 196         NULL,
 197 };
 198
 199 static const struct attribute_group spi_dev_group = {
 200         .attrs  = spi_dev_attrs,
 201 };
 202
 203 static struct attribute *spi_device_statistics_attrs[] = {
 204         &dev_attr_spi_device_messages.attr,
 205         &dev_attr_spi_device_transfers.attr,
 206         &dev_attr_spi_device_errors.attr,
 207         &dev_attr_spi_device_timedout.attr,
 208         &dev_attr_spi_device_spi_sync.attr,
 209         &dev_attr_spi_device_spi_sync_immediate.attr,
 210         &dev_attr_spi_device_spi_async.attr,
 211         &dev_attr_spi_device_bytes.attr,
 212         &dev_attr_spi_device_bytes_rx.attr,
 213         &dev_attr_spi_device_bytes_tx.attr,
 214         &dev_attr_spi_device_transfer_bytes_histo0.attr,
 215         &dev_attr_spi_device_transfer_bytes_histo1.attr,
 216         &dev_attr_spi_device_transfer_bytes_histo2.attr,
 217         &dev_attr_spi_device_transfer_bytes_histo3.attr,
 218         &dev_attr_spi_device_transfer_bytes_histo4.attr,
 219         &dev_attr_spi_device_transfer_bytes_histo5.attr,
 220         &dev_attr_spi_device_transfer_bytes_histo6.attr,
 221         &dev_attr_spi_device_transfer_bytes_histo7.attr,
 222         &dev_attr_spi_device_transfer_bytes_histo8.attr,
 223         &dev_attr_spi_device_transfer_bytes_histo9.attr,
 224         &dev_attr_spi_device_transfer_bytes_histo10.attr,
 225         &dev_attr_spi_device_transfer_bytes_histo11.attr,
 226         &dev_attr_spi_device_transfer_bytes_histo12.attr,
 227         &dev_attr_spi_device_transfer_bytes_histo13.attr,
 228         &dev_attr_spi_device_transfer_bytes_histo14.attr,
 229         &dev_attr_spi_device_transfer_bytes_histo15.attr,
 230         &dev_attr_spi_device_transfer_bytes_histo16.attr,
 231         &dev_attr_spi_device_transfers_split_maxsize.attr,
 232         NULL,
 233 };
 234
 235 static const struct attribute_group spi_device_statistics_group = {
 236         .name  = "statistics",
 237         .attrs  = spi_device_statistics_attrs,
 238 };
 239
 240 static const struct attribute_group *spi_dev_groups[] = {
 241         &spi_dev_group,
 242         &spi_device_statistics_group,
 243         NULL,
 244 };
 245
 246 static struct attribute *spi_controller_statistics_attrs[] = {
 247         &dev_attr_spi_controller_messages.attr,
 248         &dev_attr_spi_controller_transfers.attr,
 249         &dev_attr_spi_controller_errors.attr,
 250         &dev_attr_spi_controller_timedout.attr,
 251         &dev_attr_spi_controller_spi_sync.attr,
 252         &dev_attr_spi_controller_spi_sync_immediate.attr,
 253         &dev_attr_spi_controller_spi_async.attr,
 254         &dev_attr_spi_controller_bytes.attr,
 255         &dev_attr_spi_controller_bytes_rx.attr,
 256         &dev_attr_spi_controller_bytes_tx.attr,
 257         &dev_attr_spi_controller_transfer_bytes_histo0.attr,
 258         &dev_attr_spi_controller_transfer_bytes_histo1.attr,
 259         &dev_attr_spi_controller_transfer_bytes_histo2.attr,
 260         &dev_attr_spi_controller_transfer_bytes_histo3.attr,
 261         &dev_attr_spi_controller_transfer_bytes_histo4.attr,
 262         &dev_attr_spi_controller_transfer_bytes_histo5.attr,
 263         &dev_attr_spi_controller_transfer_bytes_histo6.attr,
 264         &dev_attr_spi_controller_transfer_bytes_histo7.attr,
 265         &dev_attr_spi_controller_transfer_bytes_histo8.attr,
 266         &dev_attr_spi_controller_transfer_bytes_histo9.attr,
 267         &dev_attr_spi_controller_transfer_bytes_histo10.attr,
 268         &dev_attr_spi_controller_transfer_bytes_histo11.attr,
 269         &dev_attr_spi_controller_transfer_bytes_histo12.attr,
 270         &dev_attr_spi_controller_transfer_bytes_histo13.attr,
 271         &dev_attr_spi_controller_transfer_bytes_histo14.attr,
 272         &dev_attr_spi_controller_transfer_bytes_histo15.attr,
 273         &dev_attr_spi_controller_transfer_bytes_histo16.attr,
 274         &dev_attr_spi_controller_transfers_split_maxsize.attr,
 275         NULL,
 276 };
 277
 278 static const struct attribute_group spi_controller_statistics_group = {
 279         .name  = "statistics",
 280         .attrs  = spi_controller_statistics_attrs,
 281 };
 282
 283 static const struct attribute_group *spi_master_groups[] = {
 284         &spi_controller_statistics_group,
 285         NULL,
 286 };
 287
 288 void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
 289                                        struct spi_transfer *xfer,
 290                                        struct spi_controller *ctlr)
 291 {
 292         unsigned long flags;
 293         int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
 294
 295         if (l2len < 0)
 296                 l2len = 0;
 297
 298         spin_lock_irqsave(&stats->lock, flags);
 299
 300         stats->transfers++;
 301         stats->transfer_bytes_histo[l2len]++;
 302
 303         stats->bytes += xfer->len;
 304         if ((xfer->tx_buf) &&
 305             (xfer->tx_buf != ctlr->dummy_tx))
 306                 stats->bytes_tx += xfer->len;
 307         if ((xfer->rx_buf) &&
 308             (xfer->rx_buf != ctlr->dummy_rx))
 309                 stats->bytes_rx += xfer->len;
 310
 311         spin_unlock_irqrestore(&stats->lock, flags);
 312 }
 313 EXPORT_SYMBOL_GPL(spi_statistics_add_transfer_stats);
 314
 315 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
 316  * and the sysfs version makes coldplug work too.
 317  */
 318
 319 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
 320                                                 const struct spi_device *sdev)
 321 {
 322         while (id->name[0]) {
 323                 if (!strcmp(sdev->modalias, id->name))
 324                         return id;
 325                 id++;
 326         }
 327         return NULL;
 328 }
 329
 330 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
 331 {
 332         const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
 333
 334         return spi_match_id(sdrv->id_table, sdev);
 335 }
 336 EXPORT_SYMBOL_GPL(spi_get_device_id);
 337
 338 static int spi_match_device(struct device *dev, struct device_driver *drv)
 339 {
 340         const struct spi_device *spi = to_spi_device(dev);
 341         const struct spi_driver *sdrv = to_spi_driver(drv);
 342
 343         /* Check override first, and if set, only use the named driver */
 344         if (spi->driver_override)
 345                 return strcmp(spi->driver_override, drv->name) == 0;
 346
 347         /* Attempt an OF style match */
 348         if (of_driver_match_device(dev, drv))
 349                 return 1;
 350
 351         /* Then try ACPI */
 352         if (acpi_driver_match_device(dev, drv))
 353                 return 1;
 354
 355         if (sdrv->id_table)
 356                 return !!spi_match_id(sdrv->id_table, spi);
 357
 358         return strcmp(spi->modalias, drv->name) == 0;
 359 }
 360
 361 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
 362 {
 363         const struct spi_device         *spi = to_spi_device(dev);
 364         int rc;
 365
 366         rc = acpi_device_uevent_modalias(dev, env);
 367         if (rc != -ENODEV)
 368                 return rc;
 369
 370         return add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
 371 }
 372
 373 struct bus_type spi_bus_type = {
 374         .name           = "spi",
 375         .dev_groups     = spi_dev_groups,
 376         .match          = spi_match_device,
 377         .uevent         = spi_uevent,
 378 };
 379 EXPORT_SYMBOL_GPL(spi_bus_type);
 380
 381
 382 static int spi_drv_probe(struct device *dev)
 383 {
 384         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 385         struct spi_device               *spi = to_spi_device(dev);
 386         int ret;
 387
 388         ret = of_clk_set_defaults(dev->of_node, false);
 389         if (ret)
 390                 return ret;
 391
 392         if (dev->of_node) {
 393                 spi->irq = of_irq_get(dev->of_node, 0);
 394                 if (spi->irq == -EPROBE_DEFER)
 395                         return -EPROBE_DEFER;
 396                 if (spi->irq < 0)
 397                         spi->irq = 0;
 398         }
 399
 400         ret = dev_pm_domain_attach(dev, true);
 401         if (ret)
 402                 return ret;
 403
 404         if (sdrv->probe) {
 405                 ret = sdrv->probe(spi);
 406                 if (ret)
 407                         dev_pm_domain_detach(dev, true);
 408         }
 409
 410         return ret;
 411 }
 412
 413 static int spi_drv_remove(struct device *dev)
 414 {
 415         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 416         int ret = 0;
 417
 418         if (sdrv->remove)
 419                 ret = sdrv->remove(to_spi_device(dev));
 420         dev_pm_domain_detach(dev, true);
 421
 422         return ret;
 423 }
 424
 425 static void spi_drv_shutdown(struct device *dev)
 426 {
 427         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 428
 429         sdrv->shutdown(to_spi_device(dev));
 430 }
 431
 432 /**
 433  * __spi_register_driver - register a SPI driver
 434  * @owner: owner module of the driver to register
 435  * @sdrv: the driver to register
 436  * Context: can sleep
 437  *
 438  * Return: zero on success, else a negative error code.
 439  */
 440 int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
 441 {
 442         sdrv->driver.owner = owner;
 443         sdrv->driver.bus = &spi_bus_type;
 444         sdrv->driver.probe = spi_drv_probe;
 445         sdrv->driver.remove = spi_drv_remove;
 446         if (sdrv->shutdown)
 447                 sdrv->driver.shutdown = spi_drv_shutdown;
 448         return driver_register(&sdrv->driver);
 449 }
 450 EXPORT_SYMBOL_GPL(__spi_register_driver);
 451
 452 /*-------------------------------------------------------------------------*/
 453
 454 /* SPI devices should normally not be created by SPI device drivers; that
 455  * would make them board-specific.  Similarly with SPI controller drivers.
 456  * Device registration normally goes into like arch/.../mach.../board-YYY.c
 457  * with other readonly (flashable) information about mainboard devices.
 458  */
 459
 460 struct boardinfo {
 461         struct list_head        list;
 462         struct spi_board_info   board_info;
 463 };
 464
 465 static LIST_HEAD(board_list);
 466 static LIST_HEAD(spi_controller_list);
 467
 468 /*
 469  * Used to protect add/del operation for board_info list and
 470  * spi_controller list, and their matching process
 471  * also used to protect object of type struct idr
 472  */
 473 static DEFINE_MUTEX(board_lock);
 474
 475 /*
 476  * Prevents addition of devices with same chip select and
 477  * addition of devices below an unregistering controller.
 478  */
 479 static DEFINE_MUTEX(spi_add_lock);
 480
 481 /**
 482  * spi_alloc_device - Allocate a new SPI device
 483  * @ctlr: Controller to which device is connected
 484  * Context: can sleep
 485  *
 486  * Allows a driver to allocate and initialize a spi_device without
 487  * registering it immediately.  This allows a driver to directly
 488  * fill the spi_device with device parameters before calling
 489  * spi_add_device() on it.
 490  *
 491  * Caller is responsible to call spi_add_device() on the returned
 492  * spi_device structure to add it to the SPI controller.  If the caller
 493  * needs to discard the spi_device without adding it, then it should
 494  * call spi_dev_put() on it.
 495  *
 496  * Return: a pointer to the new device, or NULL.
 497  */
 498 struct spi_device *spi_alloc_device(struct spi_controller *ctlr)
 499 {
 500         struct spi_device       *spi;
 501
 502         if (!spi_controller_get(ctlr))
 503                 return NULL;
 504
 505         spi = kzalloc(sizeof(*spi), GFP_KERNEL);
 506         if (!spi) {
 507                 spi_controller_put(ctlr);
 508                 return NULL;
 509         }
 510
 511         spi->master = spi->controller = ctlr;
 512         spi->dev.parent = &ctlr->dev;
 513         spi->dev.bus = &spi_bus_type;
 514         spi->dev.release = spidev_release;
 515         spi->cs_gpio = -ENOENT;
 516         spi->mode = ctlr->buswidth_override_bits;
 517
 518         spin_lock_init(&spi->statistics.lock);
 519
 520         device_initialize(&spi->dev);
 521         return spi;
 522 }
 523 EXPORT_SYMBOL_GPL(spi_alloc_device);
 524
 525 static void spi_dev_set_name(struct spi_device *spi)
 526 {
 527         struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
 528
 529         if (adev) {
 530                 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
 531                 return;
 532         }
 533
 534         dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->controller->dev),
 535                      spi->chip_select);
 536 }
 537
 538 static int spi_dev_check(struct device *dev, void *data)
 539 {
 540         struct spi_device *spi = to_spi_device(dev);
 541         struct spi_device *new_spi = data;
 542
 543         if (spi->controller == new_spi->controller &&
 544             spi->chip_select == new_spi->chip_select)
 545                 return -EBUSY;
 546         return 0;
 547 }
 548
 549 static void spi_cleanup(struct spi_device *spi)
 550 {
 551         if (spi->controller->cleanup)
 552                 spi->controller->cleanup(spi);
 553 }
 554
 555 /**
 556  * spi_add_device - Add spi_device allocated with spi_alloc_device
 557  * @spi: spi_device to register
 558  *
 559  * Companion function to spi_alloc_device.  Devices allocated with
 560  * spi_alloc_device can be added onto the spi bus with this function.
 561  *
 562  * Return: 0 on success; negative errno on failure
 563  */
 564 int spi_add_device(struct spi_device *spi)
 565 {
 566         struct spi_controller *ctlr = spi->controller;
 567         struct device *dev = ctlr->dev.parent;
 568         int status;
 569
 570         /* Chipselects are numbered 0..max; validate. */
 571         if (spi->chip_select >= ctlr->num_chipselect) {
 572                 dev_err(dev, "cs%d >= max %d\n", spi->chip_select,
 573                         ctlr->num_chipselect);
 574                 return -EINVAL;
 575         }
 576
 577         /* Set the bus ID string */
 578         spi_dev_set_name(spi);
 579
 580         /* We need to make sure there's no other device with this
 581          * chipselect **BEFORE** we call setup(), else we'll trash
 582          * its configuration.  Lock against concurrent add() calls.
 583          */
 584         mutex_lock(&spi_add_lock);
 585
 586         status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
 587         if (status) {
 588                 dev_err(dev, "chipselect %d already in use\n",
 589                                 spi->chip_select);
 590                 goto done;
 591         }
 592
 593         /* Controller may unregister concurrently */
 594         if (IS_ENABLED(CONFIG_SPI_DYNAMIC) &&
 595             !device_is_registered(&ctlr->dev)) {
 596                 status = -ENODEV;
 597                 goto done;
 598         }
 599
 600         /* Descriptors take precedence */
 601         if (ctlr->cs_gpiods)
 602                 spi->cs_gpiod = ctlr->cs_gpiods[spi->chip_select];
 603         else if (ctlr->cs_gpios)
 604                 spi->cs_gpio = ctlr->cs_gpios[spi->chip_select];
 605
 606         /* Drivers may modify this initial i/o setup, but will
 607          * normally rely on the device being setup.  Devices
 608          * using SPI_CS_HIGH can't coexist well otherwise...
 609          */
 610         status = spi_setup(spi);
 611         if (status < 0) {
 612                 dev_err(dev, "can't setup %s, status %d\n",
 613                                 dev_name(&spi->dev), status);
 614                 goto done;
 615         }
 616
 617         /* Device may be bound to an active driver when this returns */
 618         status = device_add(&spi->dev);
 619         if (status < 0) {
 620                 dev_err(dev, "can't add %s, status %d\n",
 621                                 dev_name(&spi->dev), status);
 622                 spi_cleanup(spi);
 623         } else {
 624                 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
 625         }
 626
 627 done:
 628         mutex_unlock(&spi_add_lock);
 629         return status;
 630 }
 631 EXPORT_SYMBOL_GPL(spi_add_device);
 632
 633 /**
 634  * spi_new_device - instantiate one new SPI device
 635  * @ctlr: Controller to which device is connected
 636  * @chip: Describes the SPI device
 637  * Context: can sleep
 638  *
 639  * On typical mainboards, this is purely internal; and it's not needed
 640  * after board init creates the hard-wired devices.  Some development
 641  * platforms may not be able to use spi_register_board_info though, and
 642  * this is exported so that for example a USB or parport based adapter
 643  * driver could add devices (which it would learn about out-of-band).
 644  *
 645  * Return: the new device, or NULL.
 646  */
 647 struct spi_device *spi_new_device(struct spi_controller *ctlr,
 648                                   struct spi_board_info *chip)
 649 {
 650         struct spi_device       *proxy;
 651         int                     status;
 652
 653         /* NOTE:  caller did any chip->bus_num checks necessary.
 654          *
 655          * Also, unless we change the return value convention to use
 656          * error-or-pointer (not NULL-or-pointer), troubleshootability
 657          * suggests syslogged diagnostics are best here (ugh).
 658          */
 659
 660         proxy = spi_alloc_device(ctlr);
 661         if (!proxy)
 662                 return NULL;
 663
 664         WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
 665
 666         proxy->chip_select = chip->chip_select;
 667         proxy->max_speed_hz = chip->max_speed_hz;
 668         proxy->mode = chip->mode;
 669         proxy->irq = chip->irq;
 670         strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
 671         proxy->dev.platform_data = (void *) chip->platform_data;
 672         proxy->controller_data = chip->controller_data;
 673         proxy->controller_state = NULL;
 674
 675         if (chip->properties) {
 676                 status = device_add_properties(&proxy->dev, chip->properties);
 677                 if (status) {
 678                         dev_err(&ctlr->dev,
 679                                 "failed to add properties to '%s': %d\n",
 680                                 chip->modalias, status);
 681                         goto err_dev_put;
 682                 }
 683         }
 684
 685         status = spi_add_device(proxy);
 686         if (status < 0)
 687                 goto err_remove_props;
 688
 689         return proxy;
 690
 691 err_remove_props:
 692         if (chip->properties)
 693                 device_remove_properties(&proxy->dev);
 694 err_dev_put:
 695         spi_dev_put(proxy);
 696         return NULL;
 697 }
 698 EXPORT_SYMBOL_GPL(spi_new_device);
 699
 700 /**
 701  * spi_unregister_device - unregister a single SPI device
 702  * @spi: spi_device to unregister
 703  *
 704  * Start making the passed SPI device vanish. Normally this would be handled
 705  * by spi_unregister_controller().
 706  */
 707 void spi_unregister_device(struct spi_device *spi)
 708 {
 709         if (!spi)
 710                 return;
 711
 712         if (spi->dev.of_node) {
 713                 of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
 714                 of_node_put(spi->dev.of_node);
 715         }
 716         if (ACPI_COMPANION(&spi->dev))
 717                 acpi_device_clear_enumerated(ACPI_COMPANION(&spi->dev));
 718         device_del(&spi->dev);
 719         spi_cleanup(spi);
 720         put_device(&spi->dev);
 721 }
 722 EXPORT_SYMBOL_GPL(spi_unregister_device);
 723
 724 static void spi_match_controller_to_boardinfo(struct spi_controller *ctlr,
 725                                               struct spi_board_info *bi)
 726 {
 727         struct spi_device *dev;
 728
 729         if (ctlr->bus_num != bi->bus_num)
 730                 return;
 731
 732         dev = spi_new_device(ctlr, bi);
 733         if (!dev)
 734                 dev_err(ctlr->dev.parent, "can't create new device for %s\n",
 735                         bi->modalias);
 736 }
 737
 738 /**
 739  * spi_register_board_info - register SPI devices for a given board
 740  * @info: array of chip descriptors
 741  * @n: how many descriptors are provided
 742  * Context: can sleep
 743  *
 744  * Board-specific early init code calls this (probably during arch_initcall)
 745  * with segments of the SPI device table.  Any device nodes are created later,
 746  * after the relevant parent SPI controller (bus_num) is defined.  We keep
 747  * this table of devices forever, so that reloading a controller driver will
 748  * not make Linux forget about these hard-wired devices.
 749  *
 750  * Other code can also call this, e.g. a particular add-on board might provide
 751  * SPI devices through its expansion connector, so code initializing that board
 752  * would naturally declare its SPI devices.
 753  *
 754  * The board info passed can safely be __initdata ... but be careful of
 755  * any embedded pointers (platform_data, etc), they're copied as-is.
 756  * Device properties are deep-copied though.
 757  *
 758  * Return: zero on success, else a negative error code.
 759  */
 760 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
 761 {
 762         struct boardinfo *bi;
 763         int i;
 764
 765         if (!n)
 766                 return 0;
 767
 768         bi = kcalloc(n, sizeof(*bi), GFP_KERNEL);
 769         if (!bi)
 770                 return -ENOMEM;
 771
 772         for (i = 0; i < n; i++, bi++, info++) {
 773                 struct spi_controller *ctlr;
 774
 775                 memcpy(&bi->board_info, info, sizeof(*info));
 776                 if (info->properties) {
 777                         bi->board_info.properties =
 778                                         property_entries_dup(info->properties);
 779                         if (IS_ERR(bi->board_info.properties))
 780                                 return PTR_ERR(bi->board_info.properties);
 781                 }
 782
 783                 mutex_lock(&board_lock);
 784                 list_add_tail(&bi->list, &board_list);
 785                 list_for_each_entry(ctlr, &spi_controller_list, list)
 786                         spi_match_controller_to_boardinfo(ctlr,
 787                                                           &bi->board_info);
 788                 mutex_unlock(&board_lock);
 789         }
 790
 791         return 0;
 792 }
 793
 794 /*-------------------------------------------------------------------------*/
 795
 796 static void spi_set_cs(struct spi_device *spi, bool enable, bool force)
 797 {
 798         bool enable1 = enable;
 799
 800         /*
 801          * Avoid calling into the driver (or doing delays) if the chip select
 802          * isn't actually changing from the last time this was called.
 803          */
 804         if (!force && (spi->controller->last_cs_enable == enable) &&
 805             (spi->controller->last_cs_mode_high == (spi->mode & SPI_CS_HIGH)))
 806                 return;
 807
 808         spi->controller->last_cs_enable = enable;
 809         spi->controller->last_cs_mode_high = spi->mode & SPI_CS_HIGH;
 810
 811         if (!spi->controller->set_cs_timing) {
 812                 if (enable1)
 813                         spi_delay_exec(&spi->controller->cs_setup, NULL);
 814                 else
 815                         spi_delay_exec(&spi->controller->cs_hold, NULL);
 816         }
 817
 818         if (spi->mode & SPI_CS_HIGH)
 819                 enable = !enable;
 820
 821         if (spi->cs_gpiod || gpio_is_valid(spi->cs_gpio)) {
 822                 if (!(spi->mode & SPI_NO_CS)) {
 823                         if (spi->cs_gpiod) {
 824                                 /*
 825                                  * Historically ACPI has no means of the GPIO polarity and
 826                                  * thus the SPISerialBus() resource defines it on the per-chip
 827                                  * basis. In order to avoid a chain of negations, the GPIO
 828                                  * polarity is considered being Active High. Even for the cases
 829                                  * when _DSD() is involved (in the updated versions of ACPI)
 830                                  * the GPIO CS polarity must be defined Active High to avoid
 831                                  * ambiguity. That's why we use enable, that takes SPI_CS_HIGH
 832                                  * into account.
 833                                  */
 834                                 if (has_acpi_companion(&spi->dev))
 835                                         gpiod_set_value_cansleep(spi->cs_gpiod, !enable);
 836                                 else
 837                                         /* Polarity handled by GPIO library */
 838                                         gpiod_set_value_cansleep(spi->cs_gpiod, enable1);
 839                         } else {
 840                                 /*
 841                                  * invert the enable line, as active low is
 842                                  * default for SPI.
 843                                  */
 844                                 gpio_set_value_cansleep(spi->cs_gpio, !enable);
 845                         }
 846                 }
 847                 /* Some SPI masters need both GPIO CS & slave_select */
 848                 if ((spi->controller->flags & SPI_MASTER_GPIO_SS) &&
 849                     spi->controller->set_cs)
 850                         spi->controller->set_cs(spi, !enable);
 851         } else if (spi->controller->set_cs) {
 852                 spi->controller->set_cs(spi, !enable);
 853         }
 854
 855         if (!spi->controller->set_cs_timing) {
 856                 if (!enable1)
 857                         spi_delay_exec(&spi->controller->cs_inactive, NULL);
 858         }
 859 }
 860
 861 #ifdef CONFIG_HAS_DMA
 862 int spi_map_buf(struct spi_controller *ctlr, struct device *dev,
 863                 struct sg_table *sgt, void *buf, size_t len,
 864                 enum dma_data_direction dir)
 865 {
 866         const bool vmalloced_buf = is_vmalloc_addr(buf);
 867         unsigned int max_seg_size = dma_get_max_seg_size(dev);
 868 #ifdef CONFIG_HIGHMEM
 869         const bool kmap_buf = ((unsigned long)buf >= PKMAP_BASE &&
 870                                 (unsigned long)buf < (PKMAP_BASE +
 871                                         (LAST_PKMAP * PAGE_SIZE)));
 872 #else
 873         const bool kmap_buf = false;
 874 #endif
 875         int desc_len;
 876         int sgs;
 877         struct page *vm_page;
 878         struct scatterlist *sg;
 879         void *sg_buf;
 880         size_t min;
 881         int i, ret;
 882
 883         if (vmalloced_buf || kmap_buf) {
 884                 desc_len = min_t(unsigned long, max_seg_size, PAGE_SIZE);
 885                 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
 886         } else if (virt_addr_valid(buf)) {
 887                 desc_len = min_t(size_t, max_seg_size, ctlr->max_dma_len);
 888                 sgs = DIV_ROUND_UP(len, desc_len);
 889         } else {
 890                 return -EINVAL;
 891         }
 892
 893         ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
 894         if (ret != 0)
 895                 return ret;
 896
 897         sg = &sgt->sgl[0];
 898         for (i = 0; i < sgs; i++) {
 899
 900                 if (vmalloced_buf || kmap_buf) {
 901                         /*
 902                          * Next scatterlist entry size is the minimum between
 903                          * the desc_len and the remaining buffer length that
 904                          * fits in a page.
 905                          */
 906                         min = min_t(size_t, desc_len,
 907                                     min_t(size_t, len,
 908                                           PAGE_SIZE - offset_in_page(buf)));
 909                         if (vmalloced_buf)
 910                                 vm_page = vmalloc_to_page(buf);
 911                         else
 912                                 vm_page = kmap_to_page(buf);
 913                         if (!vm_page) {
 914                                 sg_free_table(sgt);
 915                                 return -ENOMEM;
 916                         }
 917                         sg_set_page(sg, vm_page,
 918                                     min, offset_in_page(buf));
 919                 } else {
 920                         min = min_t(size_t, len, desc_len);
 921                         sg_buf = buf;
 922                         sg_set_buf(sg, sg_buf, min);
 923                 }
 924
 925                 buf += min;
 926                 len -= min;
 927                 sg = sg_next(sg);
 928         }
 929
 930         ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
 931         if (!ret)
 932                 ret = -ENOMEM;
 933         if (ret < 0) {
 934                 sg_free_table(sgt);
 935                 return ret;
 936         }
 937
 938         sgt->nents = ret;
 939
 940         return 0;
 941 }
 942
 943 void spi_unmap_buf(struct spi_controller *ctlr, struct device *dev,
 944                    struct sg_table *sgt, enum dma_data_direction dir)
 945 {
 946         if (sgt->orig_nents) {
 947                 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
 948                 sg_free_table(sgt);
 949                 sgt->orig_nents = 0;
 950                 sgt->nents = 0;
 951         }
 952 }
 953
 954 static int __spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
 955 {
 956         struct device *tx_dev, *rx_dev;
 957         struct spi_transfer *xfer;
 958         int ret;
 959
 960         if (!ctlr->can_dma)
 961                 return 0;
 962
 963         if (ctlr->dma_tx)
 964                 tx_dev = ctlr->dma_tx->device->dev;
 965         else
 966                 tx_dev = ctlr->dev.parent;
 967
 968         if (ctlr->dma_rx)
 969                 rx_dev = ctlr->dma_rx->device->dev;
 970         else
 971                 rx_dev = ctlr->dev.parent;
 972
 973         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 974                 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
 975                         continue;
 976
 977                 if (xfer->tx_buf != NULL) {
 978                         ret = spi_map_buf(ctlr, tx_dev, &xfer->tx_sg,
 979                                           (void *)xfer->tx_buf, xfer->len,
 980                                           DMA_TO_DEVICE);
 981                         if (ret != 0)
 982                                 return ret;
 983                 }
 984
 985                 if (xfer->rx_buf != NULL) {
 986                         ret = spi_map_buf(ctlr, rx_dev, &xfer->rx_sg,
 987                                           xfer->rx_buf, xfer->len,
 988                                           DMA_FROM_DEVICE);
 989                         if (ret != 0) {
 990                                 spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg,
 991                                               DMA_TO_DEVICE);
 992                                 return ret;
 993                         }
 994                 }
 995         }
 996
 997         ctlr->cur_msg_mapped = true;
 998
 999         return 0;
1000 }
1001
1002 static int __spi_unmap_msg(struct spi_controller *ctlr, struct spi_message *msg)
1003 {
1004         struct spi_transfer *xfer;
1005         struct device *tx_dev, *rx_dev;
1006
1007         if (!ctlr->cur_msg_mapped || !ctlr->can_dma)
1008                 return 0;
1009
1010         if (ctlr->dma_tx)
1011                 tx_dev = ctlr->dma_tx->device->dev;
1012         else
1013                 tx_dev = ctlr->dev.parent;
1014
1015         if (ctlr->dma_rx)
1016                 rx_dev = ctlr->dma_rx->device->dev;
1017         else
1018                 rx_dev = ctlr->dev.parent;
1019
1020         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1021                 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
1022                         continue;
1023
1024                 spi_unmap_buf(ctlr, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
1025                 spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
1026         }
1027
1028         ctlr->cur_msg_mapped = false;
1029
1030         return 0;
1031 }
1032 #else /* !CONFIG_HAS_DMA */
1033 static inline int __spi_map_msg(struct spi_controller *ctlr,
1034                                 struct spi_message *msg)
1035 {
1036         return 0;
1037 }
1038
1039 static inline int __spi_unmap_msg(struct spi_controller *ctlr,
1040                                   struct spi_message *msg)
1041 {
1042         return 0;
1043 }
1044 #endif /* !CONFIG_HAS_DMA */
1045
1046 static inline int spi_unmap_msg(struct spi_controller *ctlr,
1047                                 struct spi_message *msg)
1048 {
1049         struct spi_transfer *xfer;
1050
1051         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1052                 /*
1053                  * Restore the original value of tx_buf or rx_buf if they are
1054                  * NULL.
1055                  */
1056                 if (xfer->tx_buf == ctlr->dummy_tx)
1057                         xfer->tx_buf = NULL;
1058                 if (xfer->rx_buf == ctlr->dummy_rx)
1059                         xfer->rx_buf = NULL;
1060         }
1061
1062         return __spi_unmap_msg(ctlr, msg);
1063 }
1064
1065 static int spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
1066 {
1067         struct spi_transfer *xfer;
1068         void *tmp;
1069         unsigned int max_tx, max_rx;
1070
1071         if ((ctlr->flags & (SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX))
1072                 && !(msg->spi->mode & SPI_3WIRE)) {
1073                 max_tx = 0;
1074                 max_rx = 0;
1075
1076                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1077                         if ((ctlr->flags & SPI_CONTROLLER_MUST_TX) &&
1078                             !xfer->tx_buf)
1079                                 max_tx = max(xfer->len, max_tx);
1080                         if ((ctlr->flags & SPI_CONTROLLER_MUST_RX) &&
1081                             !xfer->rx_buf)
1082                                 max_rx = max(xfer->len, max_rx);
1083                 }
1084
1085                 if (max_tx) {
1086                         tmp = krealloc(ctlr->dummy_tx, max_tx,
1087                                        GFP_KERNEL | GFP_DMA);
1088                         if (!tmp)
1089                                 return -ENOMEM;
1090                         ctlr->dummy_tx = tmp;
1091                         memset(tmp, 0, max_tx);
1092                 }
1093
1094                 if (max_rx) {
1095                         tmp = krealloc(ctlr->dummy_rx, max_rx,
1096                                        GFP_KERNEL | GFP_DMA);
1097                         if (!tmp)
1098                                 return -ENOMEM;
1099                         ctlr->dummy_rx = tmp;
1100                 }
1101
1102                 if (max_tx || max_rx) {
1103                         list_for_each_entry(xfer, &msg->transfers,
1104                                             transfer_list) {
1105                                 if (!xfer->len)
1106                                         continue;
1107                                 if (!xfer->tx_buf)
1108                                         xfer->tx_buf = ctlr->dummy_tx;
1109                                 if (!xfer->rx_buf)
1110                                         xfer->rx_buf = ctlr->dummy_rx;
1111                         }
1112                 }
1113         }
1114
1115         return __spi_map_msg(ctlr, msg);
1116 }
1117
1118 static int spi_transfer_wait(struct spi_controller *ctlr,
1119                              struct spi_message *msg,
1120                              struct spi_transfer *xfer)
1121 {
1122         struct spi_statistics *statm = &ctlr->statistics;
1123         struct spi_statistics *stats = &msg->spi->statistics;
1124         u32 speed_hz = xfer->speed_hz;
1125         unsigned long long ms;
1126
1127         if (spi_controller_is_slave(ctlr)) {
1128                 if (wait_for_completion_interruptible(&ctlr->xfer_completion)) {
1129                         dev_dbg(&msg->spi->dev, "SPI transfer interrupted\n");
1130                         return -EINTR;
1131                 }
1132         } else {
1133                 if (!speed_hz)
1134                         speed_hz = 100000;
1135
1136                 ms = 8LL * 1000LL * xfer->len;
1137                 do_div(ms, speed_hz);
1138                 ms += ms + 200; /* some tolerance */
1139
1140                 if (ms > UINT_MAX)
1141                         ms = UINT_MAX;
1142
1143                 ms = wait_for_completion_timeout(&ctlr->xfer_completion,
1144                                                  msecs_to_jiffies(ms));
1145
1146                 if (ms == 0) {
1147                         SPI_STATISTICS_INCREMENT_FIELD(statm, timedout);
1148                         SPI_STATISTICS_INCREMENT_FIELD(stats, timedout);
1149                         dev_err(&msg->spi->dev,
1150                                 "SPI transfer timed out\n");
1151                         return -ETIMEDOUT;
1152                 }
1153         }
1154
1155         return 0;
1156 }
1157
1158 static void _spi_transfer_delay_ns(u32 ns)
1159 {
1160         if (!ns)
1161                 return;
1162         if (ns <= 1000) {
1163                 ndelay(ns);
1164         } else {
1165                 u32 us = DIV_ROUND_UP(ns, 1000);
1166
1167                 if (us <= 10)
1168                         udelay(us);
1169                 else
1170                         usleep_range(us, us + DIV_ROUND_UP(us, 10));
1171         }
1172 }
1173
1174 int spi_delay_to_ns(struct spi_delay *_delay, struct spi_transfer *xfer)
1175 {
1176         u32 delay = _delay->value;
1177         u32 unit = _delay->unit;
1178         u32 hz;
1179
1180         if (!delay)
1181                 return 0;
1182
1183         switch (unit) {
1184         case SPI_DELAY_UNIT_USECS:
1185                 delay *= 1000;
1186                 break;
1187         case SPI_DELAY_UNIT_NSECS: /* nothing to do here */
1188                 break;
1189         case SPI_DELAY_UNIT_SCK:
1190                 /* clock cycles need to be obtained from spi_transfer */
1191                 if (!xfer)
1192                         return -EINVAL;
1193                 /* if there is no effective speed know, then approximate
1194                  * by underestimating with half the requested hz
1195                  */
1196                 hz = xfer->effective_speed_hz ?: xfer->speed_hz / 2;
1197                 if (!hz)
1198                         return -EINVAL;
1199                 delay *= DIV_ROUND_UP(1000000000, hz);
1200                 break;
1201         default:
1202                 return -EINVAL;
1203         }
1204
1205         return delay;
1206 }
1207 EXPORT_SYMBOL_GPL(spi_delay_to_ns);
1208
1209 int spi_delay_exec(struct spi_delay *_delay, struct spi_transfer *xfer)
1210 {
1211         int delay;
1212
1213         might_sleep();
1214
1215         if (!_delay)
1216                 return -EINVAL;
1217
1218         delay = spi_delay_to_ns(_delay, xfer);
1219         if (delay < 0)
1220                 return delay;
1221
1222         _spi_transfer_delay_ns(delay);
1223
1224         return 0;
1225 }
1226 EXPORT_SYMBOL_GPL(spi_delay_exec);
1227
1228 static void _spi_transfer_cs_change_delay(struct spi_message *msg,
1229                                           struct spi_transfer *xfer)
1230 {
1231         u32 delay = xfer->cs_change_delay.value;
1232         u32 unit = xfer->cs_change_delay.unit;
1233         int ret;
1234
1235         /* return early on "fast" mode - for everything but USECS */
1236         if (!delay) {
1237                 if (unit == SPI_DELAY_UNIT_USECS)
1238                         _spi_transfer_delay_ns(10000);
1239                 return;
1240         }
1241
1242         ret = spi_delay_exec(&xfer->cs_change_delay, xfer);
1243         if (ret) {
1244                 dev_err_once(&msg->spi->dev,
1245                              "Use of unsupported delay unit %i, using default of 10us\n",
1246                              unit);
1247                 _spi_transfer_delay_ns(10000);
1248         }
1249 }
1250
1251 /*
1252  * spi_transfer_one_message - Default implementation of transfer_one_message()
1253  *
1254  * This is a standard implementation of transfer_one_message() for
1255  * drivers which implement a transfer_one() operation.  It provides
1256  * standard handling of delays and chip select management.
1257  */
1258 static int spi_transfer_one_message(struct spi_controller *ctlr,
1259                                     struct spi_message *msg)
1260 {
1261         struct spi_transfer *xfer;
1262         bool keep_cs = false;
1263         int ret = 0;
1264         struct spi_statistics *statm = &ctlr->statistics;
1265         struct spi_statistics *stats = &msg->spi->statistics;
1266
1267         spi_set_cs(msg->spi, true, false);
1268
1269         SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
1270         SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
1271
1272         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1273                 trace_spi_transfer_start(msg, xfer);
1274
1275                 spi_statistics_add_transfer_stats(statm, xfer, ctlr);
1276                 spi_statistics_add_transfer_stats(stats, xfer, ctlr);
1277
1278                 if (!ctlr->ptp_sts_supported) {
1279                         xfer->ptp_sts_word_pre = 0;
1280                         ptp_read_system_prets(xfer->ptp_sts);
1281                 }
1282
1283                 if ((xfer->tx_buf || xfer->rx_buf) && xfer->len) {
1284                         reinit_completion(&ctlr->xfer_completion);
1285
1286 fallback_pio:
1287                         ret = ctlr->transfer_one(ctlr, msg->spi, xfer);
1288                         if (ret < 0) {
1289                                 if (ctlr->cur_msg_mapped &&
1290                                    (xfer->error & SPI_TRANS_FAIL_NO_START)) {
1291                                         __spi_unmap_msg(ctlr, msg);
1292                                         ctlr->fallback = true;
1293                                         xfer->error &= ~SPI_TRANS_FAIL_NO_START;
1294                                         goto fallback_pio;
1295                                 }
1296
1297                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
1298                                                                errors);
1299                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
1300                                                                errors);
1301                                 dev_err(&msg->spi->dev,
1302                                         "SPI transfer failed: %d\n", ret);
1303                                 goto out;
1304                         }
1305
1306                         if (ret > 0) {
1307                                 ret = spi_transfer_wait(ctlr, msg, xfer);
1308                                 if (ret < 0)
1309                                         msg->status = ret;
1310                         }
1311                 } else {
1312                         if (xfer->len)
1313                                 dev_err(&msg->spi->dev,
1314                                         "Bufferless transfer has length %u\n",
1315                                         xfer->len);
1316                 }
1317
1318                 if (!ctlr->ptp_sts_supported) {
1319                         ptp_read_system_postts(xfer->ptp_sts);
1320                         xfer->ptp_sts_word_post = xfer->len;
1321                 }
1322
1323                 trace_spi_transfer_stop(msg, xfer);
1324
1325                 if (msg->status != -EINPROGRESS)
1326                         goto out;
1327
1328                 spi_transfer_delay_exec(xfer);
1329
1330                 if (xfer->cs_change) {
1331                         if (list_is_last(&xfer->transfer_list,
1332                                          &msg->transfers)) {
1333                                 keep_cs = true;
1334                         } else {
1335                                 spi_set_cs(msg->spi, false, false);
1336                                 _spi_transfer_cs_change_delay(msg, xfer);
1337                                 spi_set_cs(msg->spi, true, false);
1338                         }
1339                 }
1340
1341                 msg->actual_length += xfer->len;
1342         }
1343
1344 out:
1345         if (ret != 0 || !keep_cs)
1346                 spi_set_cs(msg->spi, false, false);
1347
1348         if (msg->status == -EINPROGRESS)
1349                 msg->status = ret;
1350
1351         if (msg->status && ctlr->handle_err)
1352                 ctlr->handle_err(ctlr, msg);
1353
1354         spi_finalize_current_message(ctlr);
1355
1356         return ret;
1357 }
1358
1359 /**
1360  * spi_finalize_current_transfer - report completion of a transfer
1361  * @ctlr: the controller reporting completion
1362  *
1363  * Called by SPI drivers using the core transfer_one_message()
1364  * implementation to notify it that the current interrupt driven
1365  * transfer has finished and the next one may be scheduled.
1366  */
1367 void spi_finalize_current_transfer(struct spi_controller *ctlr)
1368 {
1369         complete(&ctlr->xfer_completion);
1370 }
1371 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1372
1373 static void spi_idle_runtime_pm(struct spi_controller *ctlr)
1374 {
1375         if (ctlr->auto_runtime_pm) {
1376                 pm_runtime_mark_last_busy(ctlr->dev.parent);
1377                 pm_runtime_put_autosuspend(ctlr->dev.parent);
1378         }
1379 }
1380
1381 /**
1382  * __spi_pump_messages - function which processes spi message queue
1383  * @ctlr: controller to process queue for
1384  * @in_kthread: true if we are in the context of the message pump thread
1385  *
1386  * This function checks if there is any spi message in the queue that
1387  * needs processing and if so call out to the driver to initialize hardware
1388  * and transfer each message.
1389  *
1390  * Note that it is called both from the kthread itself and also from
1391  * inside spi_sync(); the queue extraction handling at the top of the
1392  * function should deal with this safely.
1393  */
1394 static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread)
1395 {
1396         struct spi_transfer *xfer;
1397         struct spi_message *msg;
1398         bool was_busy = false;
1399         unsigned long flags;
1400         int ret;
1401
1402         /* Lock queue */
1403         spin_lock_irqsave(&ctlr->queue_lock, flags);
1404
1405         /* Make sure we are not already running a message */
1406         if (ctlr->cur_msg) {
1407                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1408                 return;
1409         }
1410
1411         /* If another context is idling the device then defer */
1412         if (ctlr->idling) {
1413                 kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1414                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1415                 return;
1416         }
1417
1418         /* Check if the queue is idle */
1419         if (list_empty(&ctlr->queue) || !ctlr->running) {
1420                 if (!ctlr->busy) {
1421                         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1422                         return;
1423                 }
1424
1425                 /* Defer any non-atomic teardown to the thread */
1426                 if (!in_kthread) {
1427                         if (!ctlr->dummy_rx && !ctlr->dummy_tx &&
1428                             !ctlr->unprepare_transfer_hardware) {
1429                                 spi_idle_runtime_pm(ctlr);
1430                                 ctlr->busy = false;
1431                                 trace_spi_controller_idle(ctlr);
1432                         } else {
1433                                 kthread_queue_work(ctlr->kworker,
1434                                                    &ctlr->pump_messages);
1435                         }
1436                         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1437                         return;
1438                 }
1439
1440                 ctlr->busy = false;
1441                 ctlr->idling = true;
1442                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1443
1444                 kfree(ctlr->dummy_rx);
1445                 ctlr->dummy_rx = NULL;
1446                 kfree(ctlr->dummy_tx);
1447                 ctlr->dummy_tx = NULL;
1448                 if (ctlr->unprepare_transfer_hardware &&
1449                     ctlr->unprepare_transfer_hardware(ctlr))
1450                         dev_err(&ctlr->dev,
1451                                 "failed to unprepare transfer hardware\n");
1452                 spi_idle_runtime_pm(ctlr);
1453                 trace_spi_controller_idle(ctlr);
1454
1455                 spin_lock_irqsave(&ctlr->queue_lock, flags);
1456                 ctlr->idling = false;
1457                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1458                 return;
1459         }
1460
1461         /* Extract head of queue */
1462         msg = list_first_entry(&ctlr->queue, struct spi_message, queue);
1463         ctlr->cur_msg = msg;
1464
1465         list_del_init(&msg->queue);
1466         if (ctlr->busy)
1467                 was_busy = true;
1468         else
1469                 ctlr->busy = true;
1470         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1471
1472         mutex_lock(&ctlr->io_mutex);
1473
1474         if (!was_busy && ctlr->auto_runtime_pm) {
1475                 ret = pm_runtime_get_sync(ctlr->dev.parent);
1476                 if (ret < 0) {
1477                         pm_runtime_put_noidle(ctlr->dev.parent);
1478                         dev_err(&ctlr->dev, "Failed to power device: %d\n",
1479                                 ret);
1480                         mutex_unlock(&ctlr->io_mutex);
1481                         return;
1482                 }
1483         }
1484
1485         if (!was_busy)
1486                 trace_spi_controller_busy(ctlr);
1487
1488         if (!was_busy && ctlr->prepare_transfer_hardware) {
1489                 ret = ctlr->prepare_transfer_hardware(ctlr);
1490                 if (ret) {
1491                         dev_err(&ctlr->dev,
1492                                 "failed to prepare transfer hardware: %d\n",
1493                                 ret);
1494
1495                         if (ctlr->auto_runtime_pm)
1496                                 pm_runtime_put(ctlr->dev.parent);
1497
1498                         msg->status = ret;
1499                         spi_finalize_current_message(ctlr);
1500
1501                         mutex_unlock(&ctlr->io_mutex);
1502                         return;
1503                 }
1504         }
1505
1506         trace_spi_message_start(msg);
1507
1508         if (ctlr->prepare_message) {
1509                 ret = ctlr->prepare_message(ctlr, msg);
1510                 if (ret) {
1511                         dev_err(&ctlr->dev, "failed to prepare message: %d\n",
1512                                 ret);
1513                         msg->status = ret;
1514                         spi_finalize_current_message(ctlr);
1515                         goto out;
1516                 }
1517                 ctlr->cur_msg_prepared = true;
1518         }
1519
1520         ret = spi_map_msg(ctlr, msg);
1521         if (ret) {
1522                 msg->status = ret;
1523                 spi_finalize_current_message(ctlr);
1524                 goto out;
1525         }
1526
1527         if (!ctlr->ptp_sts_supported && !ctlr->transfer_one) {
1528                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1529                         xfer->ptp_sts_word_pre = 0;
1530                         ptp_read_system_prets(xfer->ptp_sts);
1531                 }
1532         }
1533
1534         ret = ctlr->transfer_one_message(ctlr, msg);
1535         if (ret) {
1536                 dev_err(&ctlr->dev,
1537                         "failed to transfer one message from queue\n");
1538                 goto out;
1539         }
1540
1541 out:
1542         mutex_unlock(&ctlr->io_mutex);
1543
1544         /* Prod the scheduler in case transfer_one() was busy waiting */
1545         if (!ret)
1546                 cond_resched();
1547 }
1548
1549 /**
1550  * spi_pump_messages - kthread work function which processes spi message queue
1551  * @work: pointer to kthread work struct contained in the controller struct
1552  */
1553 static void spi_pump_messages(struct kthread_work *work)
1554 {
1555         struct spi_controller *ctlr =
1556                 container_of(work, struct spi_controller, pump_messages);
1557
1558         __spi_pump_messages(ctlr, true);
1559 }
1560
1561 /**
1562  * spi_take_timestamp_pre - helper for drivers to collect the beginning of the
1563  *                          TX timestamp for the requested byte from the SPI
1564  *                          transfer. The frequency with which this function
1565  *                          must be called (once per word, once for the whole
1566  *                          transfer, once per batch of words etc) is arbitrary
1567  *                          as long as the @tx buffer offset is greater than or
1568  *                          equal to the requested byte at the time of the
1569  *                          call. The timestamp is only taken once, at the
1570  *                          first such call. It is assumed that the driver
1571  *                          advances its @tx buffer pointer monotonically.
1572  * @ctlr: Pointer to the spi_controller structure of the driver
1573  * @xfer: Pointer to the transfer being timestamped
1574  * @progress: How many words (not bytes) have been transferred so far
1575  * @irqs_off: If true, will disable IRQs and preemption for the duration of the
1576  *            transfer, for less jitter in time measurement. Only compatible
1577  *            with PIO drivers. If true, must follow up with
1578  *            spi_take_timestamp_post or otherwise system will crash.
1579  *            WARNING: for fully predictable results, the CPU frequency must
1580  *            also be under control (governor).
1581  */
1582 void spi_take_timestamp_pre(struct spi_controller *ctlr,
1583                             struct spi_transfer *xfer,
1584                             size_t progress, bool irqs_off)
1585 {
1586         if (!xfer->ptp_sts)
1587                 return;
1588
1589         if (xfer->timestamped)
1590                 return;
1591
1592         if (progress > xfer->ptp_sts_word_pre)
1593                 return;
1594
1595         /* Capture the resolution of the timestamp */
1596         xfer->ptp_sts_word_pre = progress;
1597
1598         if (irqs_off) {
1599                 local_irq_save(ctlr->irq_flags);
1600                 preempt_disable();
1601         }
1602
1603         ptp_read_system_prets(xfer->ptp_sts);
1604 }
1605 EXPORT_SYMBOL_GPL(spi_take_timestamp_pre);
1606
1607 /**
1608  * spi_take_timestamp_post - helper for drivers to collect the end of the
1609  *                           TX timestamp for the requested byte from the SPI
1610  *                           transfer. Can be called with an arbitrary
1611  *                           frequency: only the first call where @tx exceeds
1612  *                           or is equal to the requested word will be
1613  *                           timestamped.
1614  * @ctlr: Pointer to the spi_controller structure of the driver
1615  * @xfer: Pointer to the transfer being timestamped
1616  * @progress: How many words (not bytes) have been transferred so far
1617  * @irqs_off: If true, will re-enable IRQs and preemption for the local CPU.
1618  */
1619 void spi_take_timestamp_post(struct spi_controller *ctlr,
1620                              struct spi_transfer *xfer,
1621                              size_t progress, bool irqs_off)
1622 {
1623         if (!xfer->ptp_sts)
1624                 return;
1625
1626         if (xfer->timestamped)
1627                 return;
1628
1629         if (progress < xfer->ptp_sts_word_post)
1630                 return;
1631
1632         ptp_read_system_postts(xfer->ptp_sts);
1633
1634         if (irqs_off) {
1635                 local_irq_restore(ctlr->irq_flags);
1636                 preempt_enable();
1637         }
1638
1639         /* Capture the resolution of the timestamp */
1640         xfer->ptp_sts_word_post = progress;
1641
1642         xfer->timestamped = true;
1643 }
1644 EXPORT_SYMBOL_GPL(spi_take_timestamp_post);
1645
1646 /**
1647  * spi_set_thread_rt - set the controller to pump at realtime priority
1648  * @ctlr: controller to boost priority of
1649  *
1650  * This can be called because the controller requested realtime priority
1651  * (by setting the ->rt value before calling spi_register_controller()) or
1652  * because a device on the bus said that its transfers needed realtime
1653  * priority.
1654  *
1655  * NOTE: at the moment if any device on a bus says it needs realtime then
1656  * the thread will be at realtime priority for all transfers on that
1657  * controller.  If this eventually becomes a problem we may see if we can
1658  * find a way to boost the priority only temporarily during relevant
1659  * transfers.
1660  */
1661 static void spi_set_thread_rt(struct spi_controller *ctlr)
1662 {
1663         dev_info(&ctlr->dev,
1664                 "will run message pump with realtime priority\n");
1665         sched_set_fifo(ctlr->kworker->task);
1666 }
1667
1668 static int spi_init_queue(struct spi_controller *ctlr)
1669 {
1670         ctlr->running = false;
1671         ctlr->busy = false;
1672
1673         ctlr->kworker = kthread_create_worker(0, dev_name(&ctlr->dev));
1674         if (IS_ERR(ctlr->kworker)) {
1675                 dev_err(&ctlr->dev, "failed to create message pump kworker\n");
1676                 return PTR_ERR(ctlr->kworker);
1677         }
1678
1679         kthread_init_work(&ctlr->pump_messages, spi_pump_messages);
1680
1681         /*
1682          * Controller config will indicate if this controller should run the
1683          * message pump with high (realtime) priority to reduce the transfer
1684          * latency on the bus by minimising the delay between a transfer
1685          * request and the scheduling of the message pump thread. Without this
1686          * setting the message pump thread will remain at default priority.
1687          */
1688         if (ctlr->rt)
1689                 spi_set_thread_rt(ctlr);
1690
1691         return 0;
1692 }
1693
1694 /**
1695  * spi_get_next_queued_message() - called by driver to check for queued
1696  * messages
1697  * @ctlr: the controller to check for queued messages
1698  *
1699  * If there are more messages in the queue, the next message is returned from
1700  * this call.
1701  *
1702  * Return: the next message in the queue, else NULL if the queue is empty.
1703  */
1704 struct spi_message *spi_get_next_queued_message(struct spi_controller *ctlr)
1705 {
1706         struct spi_message *next;
1707         unsigned long flags;
1708
1709         /* get a pointer to the next message, if any */
1710         spin_lock_irqsave(&ctlr->queue_lock, flags);
1711         next = list_first_entry_or_null(&ctlr->queue, struct spi_message,
1712                                         queue);
1713         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1714
1715         return next;
1716 }
1717 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1718
1719 /**
1720  * spi_finalize_current_message() - the current message is complete
1721  * @ctlr: the controller to return the message to
1722  *
1723  * Called by the driver to notify the core that the message in the front of the
1724  * queue is complete and can be removed from the queue.
1725  */
1726 void spi_finalize_current_message(struct spi_controller *ctlr)
1727 {
1728         struct spi_transfer *xfer;
1729         struct spi_message *mesg;
1730         unsigned long flags;
1731         int ret;
1732
1733         spin_lock_irqsave(&ctlr->queue_lock, flags);
1734         mesg = ctlr->cur_msg;
1735         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1736
1737         if (!ctlr->ptp_sts_supported && !ctlr->transfer_one) {
1738                 list_for_each_entry(xfer, &mesg->transfers, transfer_list) {
1739                         ptp_read_system_postts(xfer->ptp_sts);
1740                         xfer->ptp_sts_word_post = xfer->len;
1741                 }
1742         }
1743
1744         if (unlikely(ctlr->ptp_sts_supported))
1745                 list_for_each_entry(xfer, &mesg->transfers, transfer_list)
1746                         WARN_ON_ONCE(xfer->ptp_sts && !xfer->timestamped);
1747
1748         spi_unmap_msg(ctlr, mesg);
1749
1750         /* In the prepare_messages callback the spi bus has the opportunity to
1751          * split a transfer to smaller chunks.
1752          * Release splited transfers here since spi_map_msg is done on the
1753          * splited transfers.
1754          */
1755         spi_res_release(ctlr, mesg);
1756
1757         if (ctlr->cur_msg_prepared && ctlr->unprepare_message) {
1758                 ret = ctlr->unprepare_message(ctlr, mesg);
1759                 if (ret) {
1760                         dev_err(&ctlr->dev, "failed to unprepare message: %d\n",
1761                                 ret);
1762                 }
1763         }
1764
1765         spin_lock_irqsave(&ctlr->queue_lock, flags);
1766         ctlr->cur_msg = NULL;
1767         ctlr->cur_msg_prepared = false;
1768         ctlr->fallback = false;
1769         kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1770         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1771
1772         trace_spi_message_done(mesg);
1773
1774         mesg->state = NULL;
1775         if (mesg->complete)
1776                 mesg->complete(mesg->context);
1777 }
1778 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1779
1780 static int spi_start_queue(struct spi_controller *ctlr)
1781 {
1782         unsigned long flags;
1783
1784         spin_lock_irqsave(&ctlr->queue_lock, flags);
1785
1786         if (ctlr->running || ctlr->busy) {
1787                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1788                 return -EBUSY;
1789         }
1790
1791         ctlr->running = true;
1792         ctlr->cur_msg = NULL;
1793         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1794
1795         kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1796
1797         return 0;
1798 }
1799
1800 static int spi_stop_queue(struct spi_controller *ctlr)
1801 {
1802         unsigned long flags;
1803         unsigned limit = 500;
1804         int ret = 0;
1805
1806         spin_lock_irqsave(&ctlr->queue_lock, flags);
1807
1808         /*
1809          * This is a bit lame, but is optimized for the common execution path.
1810          * A wait_queue on the ctlr->busy could be used, but then the common
1811          * execution path (pump_messages) would be required to call wake_up or
1812          * friends on every SPI message. Do this instead.
1813          */
1814         while ((!list_empty(&ctlr->queue) || ctlr->busy) && limit--) {
1815                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1816                 usleep_range(10000, 11000);
1817                 spin_lock_irqsave(&ctlr->queue_lock, flags);
1818         }
1819
1820         if (!list_empty(&ctlr->queue) || ctlr->busy)
1821                 ret = -EBUSY;
1822         else
1823                 ctlr->running = false;
1824
1825         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1826
1827         if (ret) {
1828                 dev_warn(&ctlr->dev, "could not stop message queue\n");
1829                 return ret;
1830         }
1831         return ret;
1832 }
1833
1834 static int spi_destroy_queue(struct spi_controller *ctlr)
1835 {
1836         int ret;
1837
1838         ret = spi_stop_queue(ctlr);
1839
1840         /*
1841          * kthread_flush_worker will block until all work is done.
1842          * If the reason that stop_queue timed out is that the work will never
1843          * finish, then it does no good to call flush/stop thread, so
1844          * return anyway.
1845          */
1846         if (ret) {
1847                 dev_err(&ctlr->dev, "problem destroying queue\n");
1848                 return ret;
1849         }
1850
1851         kthread_destroy_worker(ctlr->kworker);
1852
1853         return 0;
1854 }
1855
1856 static int __spi_queued_transfer(struct spi_device *spi,
1857                                  struct spi_message *msg,
1858                                  bool need_pump)
1859 {
1860         struct spi_controller *ctlr = spi->controller;
1861         unsigned long flags;
1862
1863         spin_lock_irqsave(&ctlr->queue_lock, flags);
1864
1865         if (!ctlr->running) {
1866                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1867                 return -ESHUTDOWN;
1868         }
1869         msg->actual_length = 0;
1870         msg->status = -EINPROGRESS;
1871
1872         list_add_tail(&msg->queue, &ctlr->queue);
1873         if (!ctlr->busy && need_pump)
1874                 kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1875
1876         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1877         return 0;
1878 }
1879
1880 /**
1881  * spi_queued_transfer - transfer function for queued transfers
1882  * @spi: spi device which is requesting transfer
1883  * @msg: spi message which is to handled is queued to driver queue
1884  *
1885  * Return: zero on success, else a negative error code.
1886  */
1887 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1888 {
1889         return __spi_queued_transfer(spi, msg, true);
1890 }
1891
1892 static int spi_controller_initialize_queue(struct spi_controller *ctlr)
1893 {
1894         int ret;
1895
1896         ctlr->transfer = spi_queued_transfer;
1897         if (!ctlr->transfer_one_message)
1898                 ctlr->transfer_one_message = spi_transfer_one_message;
1899
1900         /* Initialize and start queue */
1901         ret = spi_init_queue(ctlr);
1902         if (ret) {
1903                 dev_err(&ctlr->dev, "problem initializing queue\n");
1904                 goto err_init_queue;
1905         }
1906         ctlr->queued = true;
1907         ret = spi_start_queue(ctlr);
1908         if (ret) {
1909                 dev_err(&ctlr->dev, "problem starting queue\n");
1910                 goto err_start_queue;
1911         }
1912
1913         return 0;
1914
1915 err_start_queue:
1916         spi_destroy_queue(ctlr);
1917 err_init_queue:
1918         return ret;
1919 }
1920
1921 /**
1922  * spi_flush_queue - Send all pending messages in the queue from the callers'
1923  *                   context
1924  * @ctlr: controller to process queue for
1925  *
1926  * This should be used when one wants to ensure all pending messages have been
1927  * sent before doing something. Is used by the spi-mem code to make sure SPI
1928  * memory operations do not preempt regular SPI transfers that have been queued
1929  * before the spi-mem operation.
1930  */
1931 void spi_flush_queue(struct spi_controller *ctlr)
1932 {
1933         if (ctlr->transfer == spi_queued_transfer)
1934                 __spi_pump_messages(ctlr, false);
1935 }
1936
1937 /*-------------------------------------------------------------------------*/
1938
1939 #if defined(CONFIG_OF)
1940 static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
1941                            struct device_node *nc)
1942 {
1943         u32 value;
1944         int rc;
1945
1946         /* Mode (clock phase/polarity/etc.) */
1947         if (of_property_read_bool(nc, "spi-cpha"))
1948                 spi->mode |= SPI_CPHA;
1949         if (of_property_read_bool(nc, "spi-cpol"))
1950                 spi->mode |= SPI_CPOL;
1951         if (of_property_read_bool(nc, "spi-3wire"))
1952                 spi->mode |= SPI_3WIRE;
1953         if (of_property_read_bool(nc, "spi-lsb-first"))
1954                 spi->mode |= SPI_LSB_FIRST;
1955         if (of_property_read_bool(nc, "spi-cs-high"))
1956                 spi->mode |= SPI_CS_HIGH;
1957
1958         /* Device DUAL/QUAD mode */
1959         if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1960                 switch (value) {
1961                 case 1:
1962                         break;
1963                 case 2:
1964                         spi->mode |= SPI_TX_DUAL;
1965                         break;
1966                 case 4:
1967                         spi->mode |= SPI_TX_QUAD;
1968                         break;
1969                 case 8:
1970                         spi->mode |= SPI_TX_OCTAL;
1971                         break;
1972                 default:
1973                         dev_warn(&ctlr->dev,
1974                                 "spi-tx-bus-width %d not supported\n",
1975                                 value);
1976                         break;
1977                 }
1978         }
1979
1980         if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1981                 switch (value) {
1982                 case 1:
1983                         break;
1984                 case 2:
1985                         spi->mode |= SPI_RX_DUAL;
1986                         break;
1987                 case 4:
1988                         spi->mode |= SPI_RX_QUAD;
1989                         break;
1990                 case 8:
1991                         spi->mode |= SPI_RX_OCTAL;
1992                         break;
1993                 default:
1994                         dev_warn(&ctlr->dev,
1995                                 "spi-rx-bus-width %d not supported\n",
1996                                 value);
1997                         break;
1998                 }
1999         }
2000
2001         if (spi_controller_is_slave(ctlr)) {
2002                 if (!of_node_name_eq(nc, "slave")) {
2003                         dev_err(&ctlr->dev, "%pOF is not called 'slave'\n",
2004                                 nc);
2005                         return -EINVAL;
2006                 }
2007                 return 0;
2008         }
2009
2010         /* Device address */
2011         rc = of_property_read_u32(nc, "reg", &value);
2012         if (rc) {
2013                 dev_err(&ctlr->dev, "%pOF has no valid 'reg' property (%d)\n",
2014                         nc, rc);
2015                 return rc;
2016         }
2017         spi->chip_select = value;
2018
2019         /* Device speed */
2020         if (!of_property_read_u32(nc, "spi-max-frequency", &value))
2021                 spi->max_speed_hz = value;
2022
2023         return 0;
2024 }
2025
2026 static struct spi_device *
2027 of_register_spi_device(struct spi_controller *ctlr, struct device_node *nc)
2028 {
2029         struct spi_device *spi;
2030         int rc;
2031
2032         /* Alloc an spi_device */
2033         spi = spi_alloc_device(ctlr);
2034         if (!spi) {
2035                 dev_err(&ctlr->dev, "spi_device alloc error for %pOF\n", nc);
2036                 rc = -ENOMEM;
2037                 goto err_out;
2038         }
2039
2040         /* Select device driver */
2041         rc = of_modalias_node(nc, spi->modalias,
2042                                 sizeof(spi->modalias));
2043         if (rc < 0) {
2044                 dev_err(&ctlr->dev, "cannot find modalias for %pOF\n", nc);
2045                 goto err_out;
2046         }
2047
2048         rc = of_spi_parse_dt(ctlr, spi, nc);
2049         if (rc)
2050                 goto err_out;
2051
2052         /* Store a pointer to the node in the device structure */
2053         of_node_get(nc);
2054         spi->dev.of_node = nc;
2055         spi->dev.fwnode = of_fwnode_handle(nc);
2056
2057         /* Register the new device */
2058         rc = spi_add_device(spi);
2059         if (rc) {
2060                 dev_err(&ctlr->dev, "spi_device register error %pOF\n", nc);
2061                 goto err_of_node_put;
2062         }
2063
2064         return spi;
2065
2066 err_of_node_put:
2067         of_node_put(nc);
2068 err_out:
2069         spi_dev_put(spi);
2070         return ERR_PTR(rc);
2071 }
2072
2073 /**
2074  * of_register_spi_devices() - Register child devices onto the SPI bus
2075  * @ctlr:       Pointer to spi_controller device
2076  *
2077  * Registers an spi_device for each child node of controller node which
2078  * represents a valid SPI slave.
2079  */
2080 static void of_register_spi_devices(struct spi_controller *ctlr)
2081 {
2082         struct spi_device *spi;
2083         struct device_node *nc;
2084
2085         if (!ctlr->dev.of_node)
2086                 return;
2087
2088         for_each_available_child_of_node(ctlr->dev.of_node, nc) {
2089                 if (of_node_test_and_set_flag(nc, OF_POPULATED))
2090                         continue;
2091                 spi = of_register_spi_device(ctlr, nc);
2092                 if (IS_ERR(spi)) {
2093                         dev_warn(&ctlr->dev,
2094                                  "Failed to create SPI device for %pOF\n", nc);
2095                         of_node_clear_flag(nc, OF_POPULATED);
2096                 }
2097         }
2098 }
2099 #else
2100 static void of_register_spi_devices(struct spi_controller *ctlr) { }
2101 #endif
2102
2103 #ifdef CONFIG_ACPI
2104 struct acpi_spi_lookup {
2105         struct spi_controller   *ctlr;
2106         u32                     max_speed_hz;
2107         u32                     mode;
2108         int                     irq;
2109         u8                      bits_per_word;
2110         u8                      chip_select;
2111 };
2112
2113 static void acpi_spi_parse_apple_properties(struct acpi_device *dev,
2114                                             struct acpi_spi_lookup *lookup)
2115 {
2116         const union acpi_object *obj;
2117
2118         if (!x86_apple_machine)
2119                 return;
2120
2121         if (!acpi_dev_get_property(dev, "spiSclkPeriod", ACPI_TYPE_BUFFER, &obj)
2122             && obj->buffer.length >= 4)
2123                 lookup->max_speed_hz  = NSEC_PER_SEC / *(u32 *)obj->buffer.pointer;
2124
2125         if (!acpi_dev_get_property(dev, "spiWordSize", ACPI_TYPE_BUFFER, &obj)
2126             && obj->buffer.length == 8)
2127                 lookup->bits_per_word = *(u64 *)obj->buffer.pointer;
2128
2129         if (!acpi_dev_get_property(dev, "spiBitOrder", ACPI_TYPE_BUFFER, &obj)
2130             && obj->buffer.length == 8 && !*(u64 *)obj->buffer.pointer)
2131                 lookup->mode |= SPI_LSB_FIRST;
2132
2133         if (!acpi_dev_get_property(dev, "spiSPO", ACPI_TYPE_BUFFER, &obj)
2134             && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
2135                 lookup->mode |= SPI_CPOL;
2136
2137         if (!acpi_dev_get_property(dev, "spiSPH", ACPI_TYPE_BUFFER, &obj)
2138             && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
2139                 lookup->mode |= SPI_CPHA;
2140 }
2141
2142 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
2143 {
2144         struct acpi_spi_lookup *lookup = data;
2145         struct spi_controller *ctlr = lookup->ctlr;
2146
2147         if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
2148                 struct acpi_resource_spi_serialbus *sb;
2149                 acpi_handle parent_handle;
2150                 acpi_status status;
2151
2152                 sb = &ares->data.spi_serial_bus;
2153                 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
2154
2155                         status = acpi_get_handle(NULL,
2156                                                  sb->resource_source.string_ptr,
2157                                                  &parent_handle);
2158
2159                         if (ACPI_FAILURE(status) ||
2160                             ACPI_HANDLE(ctlr->dev.parent) != parent_handle)
2161                                 return -ENODEV;
2162
2163                         /*
2164                          * ACPI DeviceSelection numbering is handled by the
2165                          * host controller driver in Windows and can vary
2166                          * from driver to driver. In Linux we always expect
2167                          * 0 .. max - 1 so we need to ask the driver to
2168                          * translate between the two schemes.
2169                          */
2170                         if (ctlr->fw_translate_cs) {
2171                                 int cs = ctlr->fw_translate_cs(ctlr,
2172                                                 sb->device_selection);
2173                                 if (cs < 0)
2174                                         return cs;
2175                                 lookup->chip_select = cs;
2176                         } else {
2177                                 lookup->chip_select = sb->device_selection;
2178                         }
2179
2180                         lookup->max_speed_hz = sb->connection_speed;
2181                         lookup->bits_per_word = sb->data_bit_length;
2182
2183                         if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
2184                                 lookup->mode |= SPI_CPHA;
2185                         if (sb->clock_polarity == ACPI_SPI_START_HIGH)
2186                                 lookup->mode |= SPI_CPOL;
2187                         if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
2188                                 lookup->mode |= SPI_CS_HIGH;
2189                 }
2190         } else if (lookup->irq < 0) {
2191                 struct resource r;
2192
2193                 if (acpi_dev_resource_interrupt(ares, 0, &r))
2194                         lookup->irq = r.start;
2195         }
2196
2197         /* Always tell the ACPI core to skip this resource */
2198         return 1;
2199 }
2200
2201 static acpi_status acpi_register_spi_device(struct spi_controller *ctlr,
2202                                             struct acpi_device *adev)
2203 {
2204         acpi_handle parent_handle = NULL;
2205         struct list_head resource_list;
2206         struct acpi_spi_lookup lookup = {};
2207         struct spi_device *spi;
2208         int ret;
2209
2210         if (acpi_bus_get_status(adev) || !adev->status.present ||
2211             acpi_device_enumerated(adev))
2212                 return AE_OK;
2213
2214         lookup.ctlr             = ctlr;
2215         lookup.irq              = -1;
2216
2217         INIT_LIST_HEAD(&resource_list);
2218         ret = acpi_dev_get_resources(adev, &resource_list,
2219                                      acpi_spi_add_resource, &lookup);
2220         acpi_dev_free_resource_list(&resource_list);
2221
2222         if (ret < 0)
2223                 /* found SPI in _CRS but it points to another controller */
2224                 return AE_OK;
2225
2226         if (!lookup.max_speed_hz &&
2227             !ACPI_FAILURE(acpi_get_parent(adev->handle, &parent_handle)) &&
2228             ACPI_HANDLE(ctlr->dev.parent) == parent_handle) {
2229                 /* Apple does not use _CRS but nested devices for SPI slaves */
2230                 acpi_spi_parse_apple_properties(adev, &lookup);
2231         }
2232
2233         if (!lookup.max_speed_hz)
2234                 return AE_OK;
2235
2236         spi = spi_alloc_device(ctlr);
2237         if (!spi) {
2238                 dev_err(&ctlr->dev, "failed to allocate SPI device for %s\n",
2239                         dev_name(&adev->dev));
2240                 return AE_NO_MEMORY;
2241         }
2242
2243
2244         ACPI_COMPANION_SET(&spi->dev, adev);
2245         spi->max_speed_hz       = lookup.max_speed_hz;
2246         spi->mode               |= lookup.mode;
2247         spi->irq                = lookup.irq;
2248         spi->bits_per_word      = lookup.bits_per_word;
2249         spi->chip_select        = lookup.chip_select;
2250
2251         acpi_set_modalias(adev, acpi_device_hid(adev), spi->modalias,
2252                           sizeof(spi->modalias));
2253
2254         if (spi->irq < 0)
2255                 spi->irq = acpi_dev_gpio_irq_get(adev, 0);
2256
2257         acpi_device_set_enumerated(adev);
2258
2259         adev->power.flags.ignore_parent = true;
2260         if (spi_add_device(spi)) {
2261                 adev->power.flags.ignore_parent = false;
2262                 dev_err(&ctlr->dev, "failed to add SPI device %s from ACPI\n",
2263                         dev_name(&adev->dev));
2264                 spi_dev_put(spi);
2265         }
2266
2267         return AE_OK;
2268 }
2269
2270 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
2271                                        void *data, void **return_value)
2272 {
2273         struct spi_controller *ctlr = data;
2274         struct acpi_device *adev;
2275
2276         if (acpi_bus_get_device(handle, &adev))
2277                 return AE_OK;
2278
2279         return acpi_register_spi_device(ctlr, adev);
2280 }
2281
2282 #define SPI_ACPI_ENUMERATE_MAX_DEPTH            32
2283
2284 static void acpi_register_spi_devices(struct spi_controller *ctlr)
2285 {
2286         acpi_status status;
2287         acpi_handle handle;
2288
2289         handle = ACPI_HANDLE(ctlr->dev.parent);
2290         if (!handle)
2291                 return;
2292
2293         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
2294                                      SPI_ACPI_ENUMERATE_MAX_DEPTH,
2295                                      acpi_spi_add_device, NULL, ctlr, NULL);
2296         if (ACPI_FAILURE(status))
2297                 dev_warn(&ctlr->dev, "failed to enumerate SPI slaves\n");
2298 }
2299 #else
2300 static inline void acpi_register_spi_devices(struct spi_controller *ctlr) {}
2301 #endif /* CONFIG_ACPI */
2302
2303 static void spi_controller_release(struct device *dev)
2304 {
2305         struct spi_controller *ctlr;
2306
2307         ctlr = container_of(dev, struct spi_controller, dev);
2308         kfree(ctlr);
2309 }
2310
2311 static struct class spi_master_class = {
2312         .name           = "spi_master",
2313         .owner          = THIS_MODULE,
2314         .dev_release    = spi_controller_release,
2315         .dev_groups     = spi_master_groups,
2316 };
2317
2318 #ifdef CONFIG_SPI_SLAVE
2319 /**
2320  * spi_slave_abort - abort the ongoing transfer request on an SPI slave
2321  *                   controller
2322  * @spi: device used for the current transfer
2323  */
2324 int spi_slave_abort(struct spi_device *spi)
2325 {
2326         struct spi_controller *ctlr = spi->controller;
2327
2328         if (spi_controller_is_slave(ctlr) && ctlr->slave_abort)
2329                 return ctlr->slave_abort(ctlr);
2330
2331         return -ENOTSUPP;
2332 }
2333 EXPORT_SYMBOL_GPL(spi_slave_abort);
2334
2335 static int match_true(struct device *dev, void *data)
2336 {
2337         return 1;
2338 }
2339
2340 static ssize_t slave_show(struct device *dev, struct device_attribute *attr,
2341                           char *buf)
2342 {
2343         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2344                                                    dev);
2345         struct device *child;
2346
2347         child = device_find_child(&ctlr->dev, NULL, match_true);
2348         return sprintf(buf, "%s\n",
2349                        child ? to_spi_device(child)->modalias : NULL);
2350 }
2351
2352 static ssize_t slave_store(struct device *dev, struct device_attribute *attr,
2353                            const char *buf, size_t count)
2354 {
2355         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2356                                                    dev);
2357         struct spi_device *spi;
2358         struct device *child;
2359         char name[32];
2360         int rc;
2361
2362         rc = sscanf(buf, "%31s", name);
2363         if (rc != 1 || !name[0])
2364                 return -EINVAL;
2365
2366         child = device_find_child(&ctlr->dev, NULL, match_true);
2367         if (child) {
2368                 /* Remove registered slave */
2369                 device_unregister(child);
2370                 put_device(child);
2371         }
2372
2373         if (strcmp(name, "(null)")) {
2374                 /* Register new slave */
2375                 spi = spi_alloc_device(ctlr);
2376                 if (!spi)
2377                         return -ENOMEM;
2378
2379                 strlcpy(spi->modalias, name, sizeof(spi->modalias));
2380
2381                 rc = spi_add_device(spi);
2382                 if (rc) {
2383                         spi_dev_put(spi);
2384                         return rc;
2385                 }
2386         }
2387
2388         return count;
2389 }
2390
2391 static DEVICE_ATTR_RW(slave);
2392
2393 static struct attribute *spi_slave_attrs[] = {
2394         &dev_attr_slave.attr,
2395         NULL,
2396 };
2397
2398 static const struct attribute_group spi_slave_group = {
2399         .attrs = spi_slave_attrs,
2400 };
2401
2402 static const struct attribute_group *spi_slave_groups[] = {
2403         &spi_controller_statistics_group,
2404         &spi_slave_group,
2405         NULL,
2406 };
2407
2408 static struct class spi_slave_class = {
2409         .name           = "spi_slave",
2410         .owner          = THIS_MODULE,
2411         .dev_release    = spi_controller_release,
2412         .dev_groups     = spi_slave_groups,
2413 };
2414 #else
2415 extern struct class spi_slave_class;    /* dummy */
2416 #endif
2417
2418 /**
2419  * __spi_alloc_controller - allocate an SPI master or slave controller
2420  * @dev: the controller, possibly using the platform_bus
2421  * @size: how much zeroed driver-private data to allocate; the pointer to this
2422  *      memory is in the driver_data field of the returned device, accessible
2423  *      with spi_controller_get_devdata(); the memory is cacheline aligned;
2424  *      drivers granting DMA access to portions of their private data need to
2425  *      round up @size using ALIGN(size, dma_get_cache_alignment()).
2426  * @slave: flag indicating whether to allocate an SPI master (false) or SPI
2427  *      slave (true) controller
2428  * Context: can sleep
2429  *
2430  * This call is used only by SPI controller drivers, which are the
2431  * only ones directly touching chip registers.  It's how they allocate
2432  * an spi_controller structure, prior to calling spi_register_controller().
2433  *
2434  * This must be called from context that can sleep.
2435  *
2436  * The caller is responsible for assigning the bus number and initializing the
2437  * controller's methods before calling spi_register_controller(); and (after
2438  * errors adding the device) calling spi_controller_put() to prevent a memory
2439  * leak.
2440  *
2441  * Return: the SPI controller structure on success, else NULL.
2442  */
2443 struct spi_controller *__spi_alloc_controller(struct device *dev,
2444                                               unsigned int size, bool slave)
2445 {
2446         struct spi_controller   *ctlr;
2447         size_t ctlr_size = ALIGN(sizeof(*ctlr), dma_get_cache_alignment());
2448
2449         if (!dev)
2450                 return NULL;
2451
2452         ctlr = kzalloc(size + ctlr_size, GFP_KERNEL);
2453         if (!ctlr)
2454                 return NULL;
2455
2456         device_initialize(&ctlr->dev);
2457         ctlr->bus_num = -1;
2458         ctlr->num_chipselect = 1;
2459         ctlr->slave = slave;
2460         if (IS_ENABLED(CONFIG_SPI_SLAVE) && slave)
2461                 ctlr->dev.class = &spi_slave_class;
2462         else
2463                 ctlr->dev.class = &spi_master_class;
2464         ctlr->dev.parent = dev;
2465         pm_suspend_ignore_children(&ctlr->dev, true);
2466         spi_controller_set_devdata(ctlr, (void *)ctlr + ctlr_size);
2467
2468         return ctlr;
2469 }
2470 EXPORT_SYMBOL_GPL(__spi_alloc_controller);
2471
2472 static void devm_spi_release_controller(struct device *dev, void *ctlr)
2473 {
2474         spi_controller_put(*(struct spi_controller **)ctlr);
2475 }
2476
2477 /**
2478  * __devm_spi_alloc_controller - resource-managed __spi_alloc_controller()
2479  * @dev: physical device of SPI controller
2480  * @size: how much zeroed driver-private data to allocate
2481  * @slave: whether to allocate an SPI master (false) or SPI slave (true)
2482  * Context: can sleep
2483  *
2484  * Allocate an SPI controller and automatically release a reference on it
2485  * when @dev is unbound from its driver.  Drivers are thus relieved from
2486  * having to call spi_controller_put().
2487  *
2488  * The arguments to this function are identical to __spi_alloc_controller().
2489  *
2490  * Return: the SPI controller structure on success, else NULL.
2491  */
2492 struct spi_controller *__devm_spi_alloc_controller(struct device *dev,
2493                                                    unsigned int size,
2494                                                    bool slave)
2495 {
2496         struct spi_controller **ptr, *ctlr;
2497
2498         ptr = devres_alloc(devm_spi_release_controller, sizeof(*ptr),
2499                            GFP_KERNEL);
2500         if (!ptr)
2501                 return NULL;
2502
2503         ctlr = __spi_alloc_controller(dev, size, slave);
2504         if (ctlr) {
2505                 ctlr->devm_allocated = true;
2506                 *ptr = ctlr;
2507                 devres_add(dev, ptr);
2508         } else {
2509                 devres_free(ptr);
2510         }
2511
2512         return ctlr;
2513 }
2514 EXPORT_SYMBOL_GPL(__devm_spi_alloc_controller);
2515
2516 #ifdef CONFIG_OF
2517 static int of_spi_get_gpio_numbers(struct spi_controller *ctlr)
2518 {
2519         int nb, i, *cs;
2520         struct device_node *np = ctlr->dev.of_node;
2521
2522         if (!np)
2523                 return 0;
2524
2525         nb = of_gpio_named_count(np, "cs-gpios");
2526         ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2527
2528         /* Return error only for an incorrectly formed cs-gpios property */
2529         if (nb == 0 || nb == -ENOENT)
2530                 return 0;
2531         else if (nb < 0)
2532                 return nb;
2533
2534         cs = devm_kcalloc(&ctlr->dev, ctlr->num_chipselect, sizeof(int),
2535                           GFP_KERNEL);
2536         ctlr->cs_gpios = cs;
2537
2538         if (!ctlr->cs_gpios)
2539                 return -ENOMEM;
2540
2541         for (i = 0; i < ctlr->num_chipselect; i++)
2542                 cs[i] = -ENOENT;
2543
2544         for (i = 0; i < nb; i++)
2545                 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
2546
2547         return 0;
2548 }
2549 #else
2550 static int of_spi_get_gpio_numbers(struct spi_controller *ctlr)
2551 {
2552         return 0;
2553 }
2554 #endif
2555
2556 /**
2557  * spi_get_gpio_descs() - grab chip select GPIOs for the master
2558  * @ctlr: The SPI master to grab GPIO descriptors for
2559  */
2560 static int spi_get_gpio_descs(struct spi_controller *ctlr)
2561 {
2562         int nb, i;
2563         struct gpio_desc **cs;
2564         struct device *dev = &ctlr->dev;
2565         unsigned long native_cs_mask = 0;
2566         unsigned int num_cs_gpios = 0;
2567
2568         nb = gpiod_count(dev, "cs");
2569         ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2570
2571         /* No GPIOs at all is fine, else return the error */
2572         if (nb == 0 || nb == -ENOENT)
2573                 return 0;
2574         else if (nb < 0)
2575                 return nb;
2576
2577         cs = devm_kcalloc(dev, ctlr->num_chipselect, sizeof(*cs),
2578                           GFP_KERNEL);
2579         if (!cs)
2580                 return -ENOMEM;
2581         ctlr->cs_gpiods = cs;
2582
2583         for (i = 0; i < nb; i++) {
2584                 /*
2585                  * Most chipselects are active low, the inverted
2586                  * semantics are handled by special quirks in gpiolib,
2587                  * so initializing them GPIOD_OUT_LOW here means
2588                  * "unasserted", in most cases this will drive the physical
2589                  * line high.
2590                  */
2591                 cs[i] = devm_gpiod_get_index_optional(dev, "cs", i,
2592                                                       GPIOD_OUT_LOW);
2593                 if (IS_ERR(cs[i]))
2594                         return PTR_ERR(cs[i]);
2595
2596                 if (cs[i]) {
2597                         /*
2598                          * If we find a CS GPIO, name it after the device and
2599                          * chip select line.
2600                          */
2601                         char *gpioname;
2602
2603                         gpioname = devm_kasprintf(dev, GFP_KERNEL, "%s CS%d",
2604                                                   dev_name(dev), i);
2605                         if (!gpioname)
2606                                 return -ENOMEM;
2607                         gpiod_set_consumer_name(cs[i], gpioname);
2608                         num_cs_gpios++;
2609                         continue;
2610                 }
2611
2612                 if (ctlr->max_native_cs && i >= ctlr->max_native_cs) {
2613                         dev_err(dev, "Invalid native chip select %d\n", i);
2614                         return -EINVAL;
2615                 }
2616                 native_cs_mask |= BIT(i);
2617         }
2618
2619         ctlr->unused_native_cs = ffs(~native_cs_mask) - 1;
2620
2621         if ((ctlr->flags & SPI_MASTER_GPIO_SS) && num_cs_gpios &&
2622             ctlr->max_native_cs && ctlr->unused_native_cs >= ctlr->max_native_cs) {
2623                 dev_err(dev, "No unused native chip select available\n");
2624                 return -EINVAL;
2625         }
2626
2627         return 0;
2628 }
2629
2630 static int spi_controller_check_ops(struct spi_controller *ctlr)
2631 {
2632         /*
2633          * The controller may implement only the high-level SPI-memory like
2634          * operations if it does not support regular SPI transfers, and this is
2635          * valid use case.
2636          * If ->mem_ops is NULL, we request that at least one of the
2637          * ->transfer_xxx() method be implemented.
2638          */
2639         if (ctlr->mem_ops) {
2640                 if (!ctlr->mem_ops->exec_op)
2641                         return -EINVAL;
2642         } else if (!ctlr->transfer && !ctlr->transfer_one &&
2643                    !ctlr->transfer_one_message) {
2644                 return -EINVAL;
2645         }
2646
2647         return 0;
2648 }
2649
2650 /**
2651  * spi_register_controller - register SPI master or slave controller
2652  * @ctlr: initialized master, originally from spi_alloc_master() or
2653  *      spi_alloc_slave()
2654  * Context: can sleep
2655  *
2656  * SPI controllers connect to their drivers using some non-SPI bus,
2657  * such as the platform bus.  The final stage of probe() in that code
2658  * includes calling spi_register_controller() to hook up to this SPI bus glue.
2659  *
2660  * SPI controllers use board specific (often SOC specific) bus numbers,
2661  * and board-specific addressing for SPI devices combines those numbers
2662  * with chip select numbers.  Since SPI does not directly support dynamic
2663  * device identification, boards need configuration tables telling which
2664  * chip is at which address.
2665  *
2666  * This must be called from context that can sleep.  It returns zero on
2667  * success, else a negative error code (dropping the controller's refcount).
2668  * After a successful return, the caller is responsible for calling
2669  * spi_unregister_controller().
2670  *
2671  * Return: zero on success, else a negative error code.
2672  */
2673 int spi_register_controller(struct spi_controller *ctlr)
2674 {
2675         struct device           *dev = ctlr->dev.parent;
2676         struct boardinfo        *bi;
2677         int                     status;
2678         int                     id, first_dynamic;
2679
2680         if (!dev)
2681                 return -ENODEV;
2682
2683         /*
2684          * Make sure all necessary hooks are implemented before registering
2685          * the SPI controller.
2686          */
2687         status = spi_controller_check_ops(ctlr);
2688         if (status)
2689                 return status;
2690
2691         if (ctlr->bus_num >= 0) {
2692                 /* devices with a fixed bus num must check-in with the num */
2693                 mutex_lock(&board_lock);
2694                 id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
2695                         ctlr->bus_num + 1, GFP_KERNEL);
2696                 mutex_unlock(&board_lock);
2697                 if (WARN(id < 0, "couldn't get idr"))
2698                         return id == -ENOSPC ? -EBUSY : id;
2699                 ctlr->bus_num = id;
2700         } else if (ctlr->dev.of_node) {
2701                 /* allocate dynamic bus number using Linux idr */
2702                 id = of_alias_get_id(ctlr->dev.of_node, "spi");
2703                 if (id >= 0) {
2704                         ctlr->bus_num = id;
2705                         mutex_lock(&board_lock);
2706                         id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
2707                                        ctlr->bus_num + 1, GFP_KERNEL);
2708                         mutex_unlock(&board_lock);
2709                         if (WARN(id < 0, "couldn't get idr"))
2710                                 return id == -ENOSPC ? -EBUSY : id;
2711                 }
2712         }
2713         if (ctlr->bus_num < 0) {
2714                 first_dynamic = of_alias_get_highest_id("spi");
2715                 if (first_dynamic < 0)
2716                         first_dynamic = 0;
2717                 else
2718                         first_dynamic++;
2719
2720                 mutex_lock(&board_lock);
2721                 id = idr_alloc(&spi_master_idr, ctlr, first_dynamic,
2722                                0, GFP_KERNEL);
2723                 mutex_unlock(&board_lock);
2724                 if (WARN(id < 0, "couldn't get idr"))
2725                         return id;
2726                 ctlr->bus_num = id;
2727         }
2728         INIT_LIST_HEAD(&ctlr->queue);
2729         spin_lock_init(&ctlr->queue_lock);
2730         spin_lock_init(&ctlr->bus_lock_spinlock);
2731         mutex_init(&ctlr->bus_lock_mutex);
2732         mutex_init(&ctlr->io_mutex);
2733         ctlr->bus_lock_flag = 0;
2734         init_completion(&ctlr->xfer_completion);
2735         if (!ctlr->max_dma_len)
2736                 ctlr->max_dma_len = INT_MAX;
2737
2738         /* register the device, then userspace will see it.
2739          * registration fails if the bus ID is in use.
2740          */
2741         dev_set_name(&ctlr->dev, "spi%u", ctlr->bus_num);
2742
2743         if (!spi_controller_is_slave(ctlr)) {
2744                 if (ctlr->use_gpio_descriptors) {
2745                         status = spi_get_gpio_descs(ctlr);
2746                         if (status)
2747                                 goto free_bus_id;
2748                         /*
2749                          * A controller using GPIO descriptors always
2750                          * supports SPI_CS_HIGH if need be.
2751                          */
2752                         ctlr->mode_bits |= SPI_CS_HIGH;
2753                 } else {
2754                         /* Legacy code path for GPIOs from DT */
2755                         status = of_spi_get_gpio_numbers(ctlr);
2756                         if (status)
2757                                 goto free_bus_id;
2758                 }
2759         }
2760
2761         /*
2762          * Even if it's just one always-selected device, there must
2763          * be at least one chipselect.
2764          */
2765         if (!ctlr->num_chipselect) {
2766                 status = -EINVAL;
2767                 goto free_bus_id;
2768         }
2769
2770         status = device_add(&ctlr->dev);
2771         if (status < 0)
2772                 goto free_bus_id;
2773         dev_dbg(dev, "registered %s %s\n",
2774                         spi_controller_is_slave(ctlr) ? "slave" : "master",
2775                         dev_name(&ctlr->dev));
2776
2777         /*
2778          * If we're using a queued driver, start the queue. Note that we don't
2779          * need the queueing logic if the driver is only supporting high-level
2780          * memory operations.
2781          */
2782         if (ctlr->transfer) {
2783                 dev_info(dev, "controller is unqueued, this is deprecated\n");
2784         } else if (ctlr->transfer_one || ctlr->transfer_one_message) {
2785                 status = spi_controller_initialize_queue(ctlr);
2786                 if (status) {
2787                         device_del(&ctlr->dev);
2788                         goto free_bus_id;
2789                 }
2790         }
2791         /* add statistics */
2792         spin_lock_init(&ctlr->statistics.lock);
2793
2794         mutex_lock(&board_lock);
2795         list_add_tail(&ctlr->list, &spi_controller_list);
2796         list_for_each_entry(bi, &board_list, list)
2797                 spi_match_controller_to_boardinfo(ctlr, &bi->board_info);
2798         mutex_unlock(&board_lock);
2799
2800         /* Register devices from the device tree and ACPI */
2801         of_register_spi_devices(ctlr);
2802         acpi_register_spi_devices(ctlr);
2803         return status;
2804
2805 free_bus_id:
2806         mutex_lock(&board_lock);
2807         idr_remove(&spi_master_idr, ctlr->bus_num);
2808         mutex_unlock(&board_lock);
2809         return status;
2810 }
2811 EXPORT_SYMBOL_GPL(spi_register_controller);
2812
2813 static void devm_spi_unregister(struct device *dev, void *res)
2814 {
2815         spi_unregister_controller(*(struct spi_controller **)res);
2816 }
2817
2818 /**
2819  * devm_spi_register_controller - register managed SPI master or slave
2820  *      controller
2821  * @dev:    device managing SPI controller
2822  * @ctlr: initialized controller, originally from spi_alloc_master() or
2823  *      spi_alloc_slave()
2824  * Context: can sleep
2825  *
2826  * Register a SPI device as with spi_register_controller() which will
2827  * automatically be unregistered and freed.
2828  *
2829  * Return: zero on success, else a negative error code.
2830  */
2831 int devm_spi_register_controller(struct device *dev,
2832                                  struct spi_controller *ctlr)
2833 {
2834         struct spi_controller **ptr;
2835         int ret;
2836
2837         ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
2838         if (!ptr)
2839                 return -ENOMEM;
2840
2841         ret = spi_register_controller(ctlr);
2842         if (!ret) {
2843                 *ptr = ctlr;
2844                 devres_add(dev, ptr);
2845         } else {
2846                 devres_free(ptr);
2847         }
2848
2849         return ret;
2850 }
2851 EXPORT_SYMBOL_GPL(devm_spi_register_controller);
2852
2853 static int __unregister(struct device *dev, void *null)
2854 {
2855         spi_unregister_device(to_spi_device(dev));
2856         return 0;
2857 }
2858
2859 /**
2860  * spi_unregister_controller - unregister SPI master or slave controller
2861  * @ctlr: the controller being unregistered
2862  * Context: can sleep
2863  *
2864  * This call is used only by SPI controller drivers, which are the
2865  * only ones directly touching chip registers.
2866  *
2867  * This must be called from context that can sleep.
2868  *
2869  * Note that this function also drops a reference to the controller.
2870  */
2871 void spi_unregister_controller(struct spi_controller *ctlr)
2872 {
2873         struct spi_controller *found;
2874         int id = ctlr->bus_num;
2875
2876         /* Prevent addition of new devices, unregister existing ones */
2877         if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
2878                 mutex_lock(&spi_add_lock);
2879
2880         device_for_each_child(&ctlr->dev, NULL, __unregister);
2881
2882         /* First make sure that this controller was ever added */
2883         mutex_lock(&board_lock);
2884         found = idr_find(&spi_master_idr, id);
2885         mutex_unlock(&board_lock);
2886         if (ctlr->queued) {
2887                 if (spi_destroy_queue(ctlr))
2888                         dev_err(&ctlr->dev, "queue remove failed\n");
2889         }
2890         mutex_lock(&board_lock);
2891         list_del(&ctlr->list);
2892         mutex_unlock(&board_lock);
2893
2894         device_del(&ctlr->dev);
2895
2896         /* Release the last reference on the controller if its driver
2897          * has not yet been converted to devm_spi_alloc_master/slave().
2898          */
2899         if (!ctlr->devm_allocated)
2900                 put_device(&ctlr->dev);
2901
2902         /* free bus id */
2903         mutex_lock(&board_lock);
2904         if (found == ctlr)
2905                 idr_remove(&spi_master_idr, id);
2906         mutex_unlock(&board_lock);
2907
2908         if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
2909                 mutex_unlock(&spi_add_lock);
2910 }
2911 EXPORT_SYMBOL_GPL(spi_unregister_controller);
2912
2913 int spi_controller_suspend(struct spi_controller *ctlr)
2914 {
2915         int ret;
2916
2917         /* Basically no-ops for non-queued controllers */
2918         if (!ctlr->queued)
2919                 return 0;
2920
2921         ret = spi_stop_queue(ctlr);
2922         if (ret)
2923                 dev_err(&ctlr->dev, "queue stop failed\n");
2924
2925         return ret;
2926 }
2927 EXPORT_SYMBOL_GPL(spi_controller_suspend);
2928
2929 int spi_controller_resume(struct spi_controller *ctlr)
2930 {
2931         int ret;
2932
2933         if (!ctlr->queued)
2934                 return 0;
2935
2936         ret = spi_start_queue(ctlr);
2937         if (ret)
2938                 dev_err(&ctlr->dev, "queue restart failed\n");
2939
2940         return ret;
2941 }
2942 EXPORT_SYMBOL_GPL(spi_controller_resume);
2943
2944 static int __spi_controller_match(struct device *dev, const void *data)
2945 {
2946         struct spi_controller *ctlr;
2947         const u16 *bus_num = data;
2948
2949         ctlr = container_of(dev, struct spi_controller, dev);
2950         return ctlr->bus_num == *bus_num;
2951 }
2952
2953 /**
2954  * spi_busnum_to_master - look up master associated with bus_num
2955  * @bus_num: the master's bus number
2956  * Context: can sleep
2957  *
2958  * This call may be used with devices that are registered after
2959  * arch init time.  It returns a refcounted pointer to the relevant
2960  * spi_controller (which the caller must release), or NULL if there is
2961  * no such master registered.
2962  *
2963  * Return: the SPI master structure on success, else NULL.
2964  */
2965 struct spi_controller *spi_busnum_to_master(u16 bus_num)
2966 {
2967         struct device           *dev;
2968         struct spi_controller   *ctlr = NULL;
2969
2970         dev = class_find_device(&spi_master_class, NULL, &bus_num,
2971                                 __spi_controller_match);
2972         if (dev)
2973                 ctlr = container_of(dev, struct spi_controller, dev);
2974         /* reference got in class_find_device */
2975         return ctlr;
2976 }
2977 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
2978
2979 /*-------------------------------------------------------------------------*/
2980
2981 /* Core methods for SPI resource management */
2982
2983 /**
2984  * spi_res_alloc - allocate a spi resource that is life-cycle managed
2985  *                 during the processing of a spi_message while using
2986  *                 spi_transfer_one
2987  * @spi:     the spi device for which we allocate memory
2988  * @release: the release code to execute for this resource
2989  * @size:    size to alloc and return
2990  * @gfp:     GFP allocation flags
2991  *
2992  * Return: the pointer to the allocated data
2993  *
2994  * This may get enhanced in the future to allocate from a memory pool
2995  * of the @spi_device or @spi_controller to avoid repeated allocations.
2996  */
2997 void *spi_res_alloc(struct spi_device *spi,
2998                     spi_res_release_t release,
2999                     size_t size, gfp_t gfp)
3000 {
3001         struct spi_res *sres;
3002
3003         sres = kzalloc(sizeof(*sres) + size, gfp);
3004         if (!sres)
3005                 return NULL;
3006
3007         INIT_LIST_HEAD(&sres->entry);
3008         sres->release = release;
3009
3010         return sres->data;
3011 }
3012 EXPORT_SYMBOL_GPL(spi_res_alloc);
3013
3014 /**
3015  * spi_res_free - free an spi resource
3016  * @res: pointer to the custom data of a resource
3017  *
3018  */
3019 void spi_res_free(void *res)
3020 {
3021         struct spi_res *sres = container_of(res, struct spi_res, data);
3022
3023         if (!res)
3024                 return;
3025
3026         WARN_ON(!list_empty(&sres->entry));
3027         kfree(sres);
3028 }
3029 EXPORT_SYMBOL_GPL(spi_res_free);
3030
3031 /**
3032  * spi_res_add - add a spi_res to the spi_message
3033  * @message: the spi message
3034  * @res:     the spi_resource
3035  */
3036 void spi_res_add(struct spi_message *message, void *res)
3037 {
3038         struct spi_res *sres = container_of(res, struct spi_res, data);
3039
3040         WARN_ON(!list_empty(&sres->entry));
3041         list_add_tail(&sres->entry, &message->resources);
3042 }
3043 EXPORT_SYMBOL_GPL(spi_res_add);
3044
3045 /**
3046  * spi_res_release - release all spi resources for this message
3047  * @ctlr:  the @spi_controller
3048  * @message: the @spi_message
3049  */
3050 void spi_res_release(struct spi_controller *ctlr, struct spi_message *message)
3051 {
3052         struct spi_res *res, *tmp;
3053
3054         list_for_each_entry_safe_reverse(res, tmp, &message->resources, entry) {
3055                 if (res->release)
3056                         res->release(ctlr, message, res->data);
3057
3058                 list_del(&res->entry);
3059
3060                 kfree(res);
3061         }
3062 }
3063 EXPORT_SYMBOL_GPL(spi_res_release);
3064
3065 /*-------------------------------------------------------------------------*/
3066
3067 /* Core methods for spi_message alterations */
3068
3069 static void __spi_replace_transfers_release(struct spi_controller *ctlr,
3070                                             struct spi_message *msg,
3071                                             void *res)
3072 {
3073         struct spi_replaced_transfers *rxfer = res;
3074         size_t i;
3075
3076         /* call extra callback if requested */
3077         if (rxfer->release)
3078                 rxfer->release(ctlr, msg, res);
3079
3080         /* insert replaced transfers back into the message */
3081         list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
3082
3083         /* remove the formerly inserted entries */
3084         for (i = 0; i < rxfer->inserted; i++)
3085                 list_del(&rxfer->inserted_transfers[i].transfer_list);
3086 }
3087
3088 /**
3089  * spi_replace_transfers - replace transfers with several transfers
3090  *                         and register change with spi_message.resources
3091  * @msg:           the spi_message we work upon
3092  * @xfer_first:    the first spi_transfer we want to replace
3093  * @remove:        number of transfers to remove
3094  * @insert:        the number of transfers we want to insert instead
3095  * @release:       extra release code necessary in some circumstances
3096  * @extradatasize: extra data to allocate (with alignment guarantees
3097  *                 of struct @spi_transfer)
3098  * @gfp:           gfp flags
3099  *
3100  * Returns: pointer to @spi_replaced_transfers,
3101  *          PTR_ERR(...) in case of errors.
3102  */
3103 struct spi_replaced_transfers *spi_replace_transfers(
3104         struct spi_message *msg,
3105         struct spi_transfer *xfer_first,
3106         size_t remove,
3107         size_t insert,
3108         spi_replaced_release_t release,
3109         size_t extradatasize,
3110         gfp_t gfp)
3111 {
3112         struct spi_replaced_transfers *rxfer;
3113         struct spi_transfer *xfer;
3114         size_t i;
3115
3116         /* allocate the structure using spi_res */
3117         rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
3118                               struct_size(rxfer, inserted_transfers, insert)
3119                               + extradatasize,
3120                               gfp);
3121         if (!rxfer)
3122                 return ERR_PTR(-ENOMEM);
3123
3124         /* the release code to invoke before running the generic release */
3125         rxfer->release = release;
3126
3127         /* assign extradata */
3128         if (extradatasize)
3129                 rxfer->extradata =
3130                         &rxfer->inserted_transfers[insert];
3131
3132         /* init the replaced_transfers list */
3133         INIT_LIST_HEAD(&rxfer->replaced_transfers);
3134
3135         /* assign the list_entry after which we should reinsert
3136          * the @replaced_transfers - it may be spi_message.messages!
3137          */
3138         rxfer->replaced_after = xfer_first->transfer_list.prev;
3139
3140         /* remove the requested number of transfers */
3141         for (i = 0; i < remove; i++) {
3142                 /* if the entry after replaced_after it is msg->transfers
3143                  * then we have been requested to remove more transfers
3144                  * than are in the list
3145                  */
3146                 if (rxfer->replaced_after->next == &msg->transfers) {
3147                         dev_err(&msg->spi->dev,
3148                                 "requested to remove more spi_transfers than are available\n");
3149                         /* insert replaced transfers back into the message */
3150                         list_splice(&rxfer->replaced_transfers,
3151                                     rxfer->replaced_after);
3152
3153                         /* free the spi_replace_transfer structure */
3154                         spi_res_free(rxfer);
3155
3156                         /* and return with an error */
3157                         return ERR_PTR(-EINVAL);
3158                 }
3159
3160                 /* remove the entry after replaced_after from list of
3161                  * transfers and add it to list of replaced_transfers
3162                  */
3163                 list_move_tail(rxfer->replaced_after->next,
3164                                &rxfer->replaced_transfers);
3165         }
3166
3167         /* create copy of the given xfer with identical settings
3168          * based on the first transfer to get removed
3169          */
3170         for (i = 0; i < insert; i++) {
3171                 /* we need to run in reverse order */
3172                 xfer = &rxfer->inserted_transfers[insert - 1 - i];
3173
3174                 /* copy all spi_transfer data */
3175                 memcpy(xfer, xfer_first, sizeof(*xfer));
3176
3177                 /* add to list */
3178                 list_add(&xfer->transfer_list, rxfer->replaced_after);
3179
3180                 /* clear cs_change and delay for all but the last */
3181                 if (i) {
3182                         xfer->cs_change = false;
3183                         xfer->delay_usecs = 0;
3184                         xfer->delay.value = 0;
3185                 }
3186         }
3187
3188         /* set up inserted */
3189         rxfer->inserted = insert;
3190
3191         /* and register it with spi_res/spi_message */
3192         spi_res_add(msg, rxfer);
3193
3194         return rxfer;
3195 }
3196 EXPORT_SYMBOL_GPL(spi_replace_transfers);
3197
3198 static int __spi_split_transfer_maxsize(struct spi_controller *ctlr,
3199                                         struct spi_message *msg,
3200                                         struct spi_transfer **xferp,
3201                                         size_t maxsize,
3202                                         gfp_t gfp)
3203 {
3204         struct spi_transfer *xfer = *xferp, *xfers;
3205         struct spi_replaced_transfers *srt;
3206         size_t offset;
3207         size_t count, i;
3208
3209         /* calculate how many we have to replace */
3210         count = DIV_ROUND_UP(xfer->len, maxsize);
3211
3212         /* create replacement */
3213         srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
3214         if (IS_ERR(srt))
3215                 return PTR_ERR(srt);
3216         xfers = srt->inserted_transfers;
3217
3218         /* now handle each of those newly inserted spi_transfers
3219          * note that the replacements spi_transfers all are preset
3220          * to the same values as *xferp, so tx_buf, rx_buf and len
3221          * are all identical (as well as most others)
3222          * so we just have to fix up len and the pointers.
3223          *
3224          * this also includes support for the depreciated
3225          * spi_message.is_dma_mapped interface
3226          */
3227
3228         /* the first transfer just needs the length modified, so we
3229          * run it outside the loop
3230          */
3231         xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
3232
3233         /* all the others need rx_buf/tx_buf also set */
3234         for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
3235                 /* update rx_buf, tx_buf and dma */
3236                 if (xfers[i].rx_buf)
3237                         xfers[i].rx_buf += offset;
3238                 if (xfers[i].rx_dma)
3239                         xfers[i].rx_dma += offset;
3240                 if (xfers[i].tx_buf)
3241                         xfers[i].tx_buf += offset;
3242                 if (xfers[i].tx_dma)
3243                         xfers[i].tx_dma += offset;
3244
3245                 /* update length */
3246                 xfers[i].len = min(maxsize, xfers[i].len - offset);
3247         }
3248
3249         /* we set up xferp to the last entry we have inserted,
3250          * so that we skip those already split transfers
3251          */
3252         *xferp = &xfers[count - 1];
3253
3254         /* increment statistics counters */
3255         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
3256                                        transfers_split_maxsize);
3257         SPI_STATISTICS_INCREMENT_FIELD(&msg->spi->statistics,
3258                                        transfers_split_maxsize);
3259
3260         return 0;
3261 }
3262
3263 /**
3264  * spi_split_tranfers_maxsize - split spi transfers into multiple transfers
3265  *                              when an individual transfer exceeds a
3266  *                              certain size
3267  * @ctlr:    the @spi_controller for this transfer
3268  * @msg:   the @spi_message to transform
3269  * @maxsize:  the maximum when to apply this
3270  * @gfp: GFP allocation flags
3271  *
3272  * Return: status of transformation
3273  */
3274 int spi_split_transfers_maxsize(struct spi_controller *ctlr,
3275                                 struct spi_message *msg,
3276                                 size_t maxsize,
3277                                 gfp_t gfp)
3278 {
3279         struct spi_transfer *xfer;
3280         int ret;
3281
3282         /* iterate over the transfer_list,
3283          * but note that xfer is advanced to the last transfer inserted
3284          * to avoid checking sizes again unnecessarily (also xfer does
3285          * potentiall belong to a different list by the time the
3286          * replacement has happened
3287          */
3288         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
3289                 if (xfer->len > maxsize) {
3290                         ret = __spi_split_transfer_maxsize(ctlr, msg, &xfer,
3291                                                            maxsize, gfp);
3292                         if (ret)
3293                                 return ret;
3294                 }
3295         }
3296
3297         return 0;
3298 }
3299 EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
3300
3301 /*-------------------------------------------------------------------------*/
3302
3303 /* Core methods for SPI controller protocol drivers.  Some of the
3304  * other core methods are currently defined as inline functions.
3305  */
3306
3307 static int __spi_validate_bits_per_word(struct spi_controller *ctlr,
3308                                         u8 bits_per_word)
3309 {
3310         if (ctlr->bits_per_word_mask) {
3311                 /* Only 32 bits fit in the mask */
3312                 if (bits_per_word > 32)
3313                         return -EINVAL;
3314                 if (!(ctlr->bits_per_word_mask & SPI_BPW_MASK(bits_per_word)))
3315                         return -EINVAL;
3316         }
3317
3318         return 0;
3319 }
3320
3321 /**
3322  * spi_setup - setup SPI mode and clock rate
3323  * @spi: the device whose settings are being modified
3324  * Context: can sleep, and no requests are queued to the device
3325  *
3326  * SPI protocol drivers may need to update the transfer mode if the
3327  * device doesn't work with its default.  They may likewise need
3328  * to update clock rates or word sizes from initial values.  This function
3329  * changes those settings, and must be called from a context that can sleep.
3330  * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
3331  * effect the next time the device is selected and data is transferred to
3332  * or from it.  When this function returns, the spi device is deselected.
3333  *
3334  * Note that this call will fail if the protocol driver specifies an option
3335  * that the underlying controller or its driver does not support.  For
3336  * example, not all hardware supports wire transfers using nine bit words,
3337  * LSB-first wire encoding, or active-high chipselects.
3338  *
3339  * Return: zero on success, else a negative error code.
3340  */
3341 int spi_setup(struct spi_device *spi)
3342 {
3343         unsigned        bad_bits, ugly_bits;
3344         int             status;
3345
3346         /* check mode to prevent that DUAL and QUAD set at the same time
3347          */
3348         if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
3349                 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
3350                 dev_err(&spi->dev,
3351                 "setup: can not select dual and quad at the same time\n");
3352                 return -EINVAL;
3353         }
3354         /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
3355          */
3356         if ((spi->mode & SPI_3WIRE) && (spi->mode &
3357                 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
3358                  SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL)))
3359                 return -EINVAL;
3360         /* help drivers fail *cleanly* when they need options
3361          * that aren't supported with their current controller
3362          * SPI_CS_WORD has a fallback software implementation,
3363          * so it is ignored here.
3364          */
3365         bad_bits = spi->mode & ~(spi->controller->mode_bits | SPI_CS_WORD);
3366         /* nothing prevents from working with active-high CS in case if it
3367          * is driven by GPIO.
3368          */
3369         if (gpio_is_valid(spi->cs_gpio))
3370                 bad_bits &= ~SPI_CS_HIGH;
3371         ugly_bits = bad_bits &
3372                     (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
3373                      SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL);
3374         if (ugly_bits) {
3375                 dev_warn(&spi->dev,
3376                          "setup: ignoring unsupported mode bits %x\n",
3377                          ugly_bits);
3378                 spi->mode &= ~ugly_bits;
3379                 bad_bits &= ~ugly_bits;
3380         }
3381         if (bad_bits) {
3382                 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
3383                         bad_bits);
3384                 return -EINVAL;
3385         }
3386
3387         if (!spi->bits_per_word)
3388                 spi->bits_per_word = 8;
3389
3390         status = __spi_validate_bits_per_word(spi->controller,
3391                                               spi->bits_per_word);
3392         if (status)
3393                 return status;
3394
3395         if (!spi->max_speed_hz)
3396                 spi->max_speed_hz = spi->controller->max_speed_hz;
3397
3398         mutex_lock(&spi->controller->io_mutex);
3399
3400         if (spi->controller->setup)
3401                 status = spi->controller->setup(spi);
3402
3403         if (spi->controller->auto_runtime_pm && spi->controller->set_cs) {
3404                 status = pm_runtime_get_sync(spi->controller->dev.parent);
3405                 if (status < 0) {
3406                         mutex_unlock(&spi->controller->io_mutex);
3407                         pm_runtime_put_noidle(spi->controller->dev.parent);
3408                         dev_err(&spi->controller->dev, "Failed to power device: %d\n",
3409                                 status);
3410                         return status;
3411                 }
3412
3413                 /*
3414                  * We do not want to return positive value from pm_runtime_get,
3415                  * there are many instances of devices calling spi_setup() and
3416                  * checking for a non-zero return value instead of a negative
3417                  * return value.
3418                  */
3419                 status = 0;
3420
3421                 spi_set_cs(spi, false, true);
3422                 pm_runtime_mark_last_busy(spi->controller->dev.parent);
3423                 pm_runtime_put_autosuspend(spi->controller->dev.parent);
3424         } else {
3425                 spi_set_cs(spi, false, true);
3426         }
3427
3428         mutex_unlock(&spi->controller->io_mutex);
3429
3430         if (spi->rt && !spi->controller->rt) {
3431                 spi->controller->rt = true;
3432                 spi_set_thread_rt(spi->controller);
3433         }
3434
3435         dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
3436                         (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
3437                         (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
3438                         (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
3439                         (spi->mode & SPI_3WIRE) ? "3wire, " : "",
3440                         (spi->mode & SPI_LOOP) ? "loopback, " : "",
3441                         spi->bits_per_word, spi->max_speed_hz,
3442                         status);
3443
3444         return status;
3445 }
3446 EXPORT_SYMBOL_GPL(spi_setup);
3447
3448 /**
3449  * spi_set_cs_timing - configure CS setup, hold, and inactive delays
3450  * @spi: the device that requires specific CS timing configuration
3451  * @setup: CS setup time specified via @spi_delay
3452  * @hold: CS hold time specified via @spi_delay
3453  * @inactive: CS inactive delay between transfers specified via @spi_delay
3454  *
3455  * Return: zero on success, else a negative error code.
3456  */
3457 int spi_set_cs_timing(struct spi_device *spi, struct spi_delay *setup,
3458                       struct spi_delay *hold, struct spi_delay *inactive)
3459 {
3460         size_t len;
3461
3462         if (spi->controller->set_cs_timing)
3463                 return spi->controller->set_cs_timing(spi, setup, hold,
3464                                                       inactive);
3465
3466         if ((setup && setup->unit == SPI_DELAY_UNIT_SCK) ||
3467             (hold && hold->unit == SPI_DELAY_UNIT_SCK) ||
3468             (inactive && inactive->unit == SPI_DELAY_UNIT_SCK)) {
3469                 dev_err(&spi->dev,
3470                         "Clock-cycle delays for CS not supported in SW mode\n");
3471                 return -ENOTSUPP;
3472         }
3473
3474         len = sizeof(struct spi_delay);
3475
3476         /* copy delays to controller */
3477         if (setup)
3478                 memcpy(&spi->controller->cs_setup, setup, len);
3479         else
3480                 memset(&spi->controller->cs_setup, 0, len);
3481
3482         if (hold)
3483                 memcpy(&spi->controller->cs_hold, hold, len);
3484         else
3485                 memset(&spi->controller->cs_hold, 0, len);
3486
3487         if (inactive)
3488                 memcpy(&spi->controller->cs_inactive, inactive, len);
3489         else
3490                 memset(&spi->controller->cs_inactive, 0, len);
3491
3492         return 0;
3493 }
3494 EXPORT_SYMBOL_GPL(spi_set_cs_timing);
3495
3496 static int _spi_xfer_word_delay_update(struct spi_transfer *xfer,
3497                                        struct spi_device *spi)
3498 {
3499         int delay1, delay2;
3500
3501         delay1 = spi_delay_to_ns(&xfer->word_delay, xfer);
3502         if (delay1 < 0)
3503                 return delay1;
3504
3505         delay2 = spi_delay_to_ns(&spi->word_delay, xfer);
3506         if (delay2 < 0)
3507                 return delay2;
3508
3509         if (delay1 < delay2)
3510                 memcpy(&xfer->word_delay, &spi->word_delay,
3511                        sizeof(xfer->word_delay));
3512
3513         return 0;
3514 }
3515
3516 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
3517 {
3518         struct spi_controller *ctlr = spi->controller;
3519         struct spi_transfer *xfer;
3520         int w_size;
3521
3522         if (list_empty(&message->transfers))
3523                 return -EINVAL;
3524
3525         /* If an SPI controller does not support toggling the CS line on each
3526          * transfer (indicated by the SPI_CS_WORD flag) or we are using a GPIO
3527          * for the CS line, we can emulate the CS-per-word hardware function by
3528          * splitting transfers into one-word transfers and ensuring that
3529          * cs_change is set for each transfer.
3530          */
3531         if ((spi->mode & SPI_CS_WORD) && (!(ctlr->mode_bits & SPI_CS_WORD) ||
3532                                           spi->cs_gpiod ||
3533                                           gpio_is_valid(spi->cs_gpio))) {
3534                 size_t maxsize;
3535                 int ret;
3536
3537                 maxsize = (spi->bits_per_word + 7) / 8;
3538
3539                 /* spi_split_transfers_maxsize() requires message->spi */
3540                 message->spi = spi;
3541
3542                 ret = spi_split_transfers_maxsize(ctlr, message, maxsize,
3543                                                   GFP_KERNEL);
3544                 if (ret)
3545                         return ret;
3546
3547                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3548                         /* don't change cs_change on the last entry in the list */
3549                         if (list_is_last(&xfer->transfer_list, &message->transfers))
3550                                 break;
3551                         xfer->cs_change = 1;
3552                 }
3553         }
3554
3555         /* Half-duplex links include original MicroWire, and ones with
3556          * only one data pin like SPI_3WIRE (switches direction) or where
3557          * either MOSI or MISO is missing.  They can also be caused by
3558          * software limitations.
3559          */
3560         if ((ctlr->flags & SPI_CONTROLLER_HALF_DUPLEX) ||
3561             (spi->mode & SPI_3WIRE)) {
3562                 unsigned flags = ctlr->flags;
3563
3564                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3565                         if (xfer->rx_buf && xfer->tx_buf)
3566                                 return -EINVAL;
3567                         if ((flags & SPI_CONTROLLER_NO_TX) && xfer->tx_buf)
3568                                 return -EINVAL;
3569                         if ((flags & SPI_CONTROLLER_NO_RX) && xfer->rx_buf)
3570                                 return -EINVAL;
3571                 }
3572         }
3573
3574         /**
3575          * Set transfer bits_per_word and max speed as spi device default if
3576          * it is not set for this transfer.
3577          * Set transfer tx_nbits and rx_nbits as single transfer default
3578          * (SPI_NBITS_SINGLE) if it is not set for this transfer.
3579          * Ensure transfer word_delay is at least as long as that required by
3580          * device itself.
3581          */
3582         message->frame_length = 0;
3583         list_for_each_entry(xfer, &message->transfers, transfer_list) {
3584                 xfer->effective_speed_hz = 0;
3585                 message->frame_length += xfer->len;
3586                 if (!xfer->bits_per_word)
3587                         xfer->bits_per_word = spi->bits_per_word;
3588
3589                 if (!xfer->speed_hz)
3590                         xfer->speed_hz = spi->max_speed_hz;
3591
3592                 if (ctlr->max_speed_hz && xfer->speed_hz > ctlr->max_speed_hz)
3593                         xfer->speed_hz = ctlr->max_speed_hz;
3594
3595                 if (__spi_validate_bits_per_word(ctlr, xfer->bits_per_word))
3596                         return -EINVAL;
3597
3598                 /*
3599                  * SPI transfer length should be multiple of SPI word size
3600                  * where SPI word size should be power-of-two multiple
3601                  */
3602                 if (xfer->bits_per_word <= 8)
3603                         w_size = 1;
3604                 else if (xfer->bits_per_word <= 16)
3605                         w_size = 2;
3606                 else
3607                         w_size = 4;
3608
3609                 /* No partial transfers accepted */
3610                 if (xfer->len % w_size)
3611                         return -EINVAL;
3612
3613                 if (xfer->speed_hz && ctlr->min_speed_hz &&
3614                     xfer->speed_hz < ctlr->min_speed_hz)
3615                         return -EINVAL;
3616
3617                 if (xfer->tx_buf && !xfer->tx_nbits)
3618                         xfer->tx_nbits = SPI_NBITS_SINGLE;
3619                 if (xfer->rx_buf && !xfer->rx_nbits)
3620                         xfer->rx_nbits = SPI_NBITS_SINGLE;
3621                 /* check transfer tx/rx_nbits:
3622                  * 1. check the value matches one of single, dual and quad
3623                  * 2. check tx/rx_nbits match the mode in spi_device
3624                  */
3625                 if (xfer->tx_buf) {
3626                         if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
3627                                 xfer->tx_nbits != SPI_NBITS_DUAL &&
3628                                 xfer->tx_nbits != SPI_NBITS_QUAD)
3629                                 return -EINVAL;
3630                         if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
3631                                 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
3632                                 return -EINVAL;
3633                         if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
3634                                 !(spi->mode & SPI_TX_QUAD))
3635                                 return -EINVAL;
3636                 }
3637                 /* check transfer rx_nbits */
3638                 if (xfer->rx_buf) {
3639                         if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
3640                                 xfer->rx_nbits != SPI_NBITS_DUAL &&
3641                                 xfer->rx_nbits != SPI_NBITS_QUAD)
3642                                 return -EINVAL;
3643                         if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
3644                                 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
3645                                 return -EINVAL;
3646                         if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
3647                                 !(spi->mode & SPI_RX_QUAD))
3648                                 return -EINVAL;
3649                 }
3650
3651                 if (_spi_xfer_word_delay_update(xfer, spi))
3652                         return -EINVAL;
3653         }
3654
3655         message->status = -EINPROGRESS;
3656
3657         return 0;
3658 }
3659
3660 static int __spi_async(struct spi_device *spi, struct spi_message *message)
3661 {
3662         struct spi_controller *ctlr = spi->controller;
3663         struct spi_transfer *xfer;
3664
3665         /*
3666          * Some controllers do not support doing regular SPI transfers. Return
3667          * ENOTSUPP when this is the case.
3668          */
3669         if (!ctlr->transfer)
3670                 return -ENOTSUPP;
3671
3672         message->spi = spi;
3673
3674         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_async);
3675         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
3676
3677         trace_spi_message_submit(message);
3678
3679         if (!ctlr->ptp_sts_supported) {
3680                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3681                         xfer->ptp_sts_word_pre = 0;
3682                         ptp_read_system_prets(xfer->ptp_sts);
3683                 }
3684         }
3685
3686         return ctlr->transfer(spi, message);
3687 }
3688
3689 /**
3690  * spi_async - asynchronous SPI transfer
3691  * @spi: device with which data will be exchanged
3692  * @message: describes the data transfers, including completion callback
3693  * Context: any (irqs may be blocked, etc)
3694  *
3695  * This call may be used in_irq and other contexts which can't sleep,
3696  * as well as from task contexts which can sleep.
3697  *
3698  * The completion callback is invoked in a context which can't sleep.
3699  * Before that invocation, the value of message->status is undefined.
3700  * When the callback is issued, message->status holds either zero (to
3701  * indicate complete success) or a negative error code.  After that
3702  * callback returns, the driver which issued the transfer request may
3703  * deallocate the associated memory; it's no longer in use by any SPI
3704  * core or controller driver code.
3705  *
3706  * Note that although all messages to a spi_device are handled in
3707  * FIFO order, messages may go to different devices in other orders.
3708  * Some device might be higher priority, or have various "hard" access
3709  * time requirements, for example.
3710  *
3711  * On detection of any fault during the transfer, processing of
3712  * the entire message is aborted, and the device is deselected.
3713  * Until returning from the associated message completion callback,
3714  * no other spi_message queued to that device will be processed.
3715  * (This rule applies equally to all the synchronous transfer calls,
3716  * which are wrappers around this core asynchronous primitive.)
3717  *
3718  * Return: zero on success, else a negative error code.
3719  */
3720 int spi_async(struct spi_device *spi, struct spi_message *message)
3721 {
3722         struct spi_controller *ctlr = spi->controller;
3723         int ret;
3724         unsigned long flags;
3725
3726         ret = __spi_validate(spi, message);
3727         if (ret != 0)
3728                 return ret;
3729
3730         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3731
3732         if (ctlr->bus_lock_flag)
3733                 ret = -EBUSY;
3734         else
3735                 ret = __spi_async(spi, message);
3736
3737         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3738
3739         return ret;
3740 }
3741 EXPORT_SYMBOL_GPL(spi_async);
3742
3743 /**
3744  * spi_async_locked - version of spi_async with exclusive bus usage
3745  * @spi: device with which data will be exchanged
3746  * @message: describes the data transfers, including completion callback
3747  * Context: any (irqs may be blocked, etc)
3748  *
3749  * This call may be used in_irq and other contexts which can't sleep,
3750  * as well as from task contexts which can sleep.
3751  *
3752  * The completion callback is invoked in a context which can't sleep.
3753  * Before that invocation, the value of message->status is undefined.
3754  * When the callback is issued, message->status holds either zero (to
3755  * indicate complete success) or a negative error code.  After that
3756  * callback returns, the driver which issued the transfer request may
3757  * deallocate the associated memory; it's no longer in use by any SPI
3758  * core or controller driver code.
3759  *
3760  * Note that although all messages to a spi_device are handled in
3761  * FIFO order, messages may go to different devices in other orders.
3762  * Some device might be higher priority, or have various "hard" access
3763  * time requirements, for example.
3764  *
3765  * On detection of any fault during the transfer, processing of
3766  * the entire message is aborted, and the device is deselected.
3767  * Until returning from the associated message completion callback,
3768  * no other spi_message queued to that device will be processed.
3769  * (This rule applies equally to all the synchronous transfer calls,
3770  * which are wrappers around this core asynchronous primitive.)
3771  *
3772  * Return: zero on success, else a negative error code.
3773  */
3774 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
3775 {
3776         struct spi_controller *ctlr = spi->controller;
3777         int ret;
3778         unsigned long flags;
3779
3780         ret = __spi_validate(spi, message);
3781         if (ret != 0)
3782                 return ret;
3783
3784         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3785
3786         ret = __spi_async(spi, message);
3787
3788         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3789
3790         return ret;
3791
3792 }
3793 EXPORT_SYMBOL_GPL(spi_async_locked);
3794
3795 /*-------------------------------------------------------------------------*/
3796
3797 /* Utility methods for SPI protocol drivers, layered on
3798  * top of the core.  Some other utility methods are defined as
3799  * inline functions.
3800  */
3801
3802 static void spi_complete(void *arg)
3803 {
3804         complete(arg);
3805 }
3806
3807 static int __spi_sync(struct spi_device *spi, struct spi_message *message)
3808 {
3809         DECLARE_COMPLETION_ONSTACK(done);
3810         int status;
3811         struct spi_controller *ctlr = spi->controller;
3812         unsigned long flags;
3813
3814         status = __spi_validate(spi, message);
3815         if (status != 0)
3816                 return status;
3817
3818         message->complete = spi_complete;
3819         message->context = &done;
3820         message->spi = spi;
3821
3822         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_sync);
3823         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
3824
3825         /* If we're not using the legacy transfer method then we will
3826          * try to transfer in the calling context so special case.
3827          * This code would be less tricky if we could remove the
3828          * support for driver implemented message queues.
3829          */
3830         if (ctlr->transfer == spi_queued_transfer) {
3831                 spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3832
3833                 trace_spi_message_submit(message);
3834
3835                 status = __spi_queued_transfer(spi, message, false);
3836
3837                 spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3838         } else {
3839                 status = spi_async_locked(spi, message);
3840         }
3841
3842         if (status == 0) {
3843                 /* Push out the messages in the calling context if we
3844                  * can.
3845                  */
3846                 if (ctlr->transfer == spi_queued_transfer) {
3847                         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
3848                                                        spi_sync_immediate);
3849                         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
3850                                                        spi_sync_immediate);
3851                         __spi_pump_messages(ctlr, false);
3852                 }
3853
3854                 wait_for_completion(&done);
3855                 status = message->status;
3856         }
3857         message->context = NULL;
3858         return status;
3859 }
3860
3861 /**
3862  * spi_sync - blocking/synchronous SPI data transfers
3863  * @spi: device with which data will be exchanged
3864  * @message: describes the data transfers
3865  * Context: can sleep
3866  *
3867  * This call may only be used from a context that may sleep.  The sleep
3868  * is non-interruptible, and has no timeout.  Low-overhead controller
3869  * drivers may DMA directly into and out of the message buffers.
3870  *
3871  * Note that the SPI device's chip select is active during the message,
3872  * and then is normally disabled between messages.  Drivers for some
3873  * frequently-used devices may want to minimize costs of selecting a chip,
3874  * by leaving it selected in anticipation that the next message will go
3875  * to the same chip.  (That may increase power usage.)
3876  *
3877  * Also, the caller is guaranteeing that the memory associated with the
3878  * message will not be freed before this call returns.
3879  *
3880  * Return: zero on success, else a negative error code.
3881  */
3882 int spi_sync(struct spi_device *spi, struct spi_message *message)
3883 {
3884         int ret;
3885
3886         mutex_lock(&spi->controller->bus_lock_mutex);
3887         ret = __spi_sync(spi, message);
3888         mutex_unlock(&spi->controller->bus_lock_mutex);
3889
3890         return ret;
3891 }
3892 EXPORT_SYMBOL_GPL(spi_sync);
3893
3894 /**
3895  * spi_sync_locked - version of spi_sync with exclusive bus usage
3896  * @spi: device with which data will be exchanged
3897  * @message: describes the data transfers
3898  * Context: can sleep
3899  *
3900  * This call may only be used from a context that may sleep.  The sleep
3901  * is non-interruptible, and has no timeout.  Low-overhead controller
3902  * drivers may DMA directly into and out of the message buffers.
3903  *
3904  * This call should be used by drivers that require exclusive access to the
3905  * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
3906  * be released by a spi_bus_unlock call when the exclusive access is over.
3907  *
3908  * Return: zero on success, else a negative error code.
3909  */
3910 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
3911 {
3912         return __spi_sync(spi, message);
3913 }
3914 EXPORT_SYMBOL_GPL(spi_sync_locked);
3915
3916 /**
3917  * spi_bus_lock - obtain a lock for exclusive SPI bus usage
3918  * @ctlr: SPI bus master that should be locked for exclusive bus access
3919  * Context: can sleep
3920  *
3921  * This call may only be used from a context that may sleep.  The sleep
3922  * is non-interruptible, and has no timeout.
3923  *
3924  * This call should be used by drivers that require exclusive access to the
3925  * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
3926  * exclusive access is over. Data transfer must be done by spi_sync_locked
3927  * and spi_async_locked calls when the SPI bus lock is held.
3928  *
3929  * Return: always zero.
3930  */
3931 int spi_bus_lock(struct spi_controller *ctlr)
3932 {
3933         unsigned long flags;
3934
3935         mutex_lock(&ctlr->bus_lock_mutex);
3936
3937         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3938         ctlr->bus_lock_flag = 1;
3939         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3940
3941         /* mutex remains locked until spi_bus_unlock is called */
3942
3943         return 0;
3944 }
3945 EXPORT_SYMBOL_GPL(spi_bus_lock);
3946
3947 /**
3948  * spi_bus_unlock - release the lock for exclusive SPI bus usage
3949  * @ctlr: SPI bus master that was locked for exclusive bus access
3950  * Context: can sleep
3951  *
3952  * This call may only be used from a context that may sleep.  The sleep
3953  * is non-interruptible, and has no timeout.
3954  *
3955  * This call releases an SPI bus lock previously obtained by an spi_bus_lock
3956  * call.
3957  *
3958  * Return: always zero.
3959  */
3960 int spi_bus_unlock(struct spi_controller *ctlr)
3961 {
3962         ctlr->bus_lock_flag = 0;
3963
3964         mutex_unlock(&ctlr->bus_lock_mutex);
3965
3966         return 0;
3967 }
3968 EXPORT_SYMBOL_GPL(spi_bus_unlock);
3969
3970 /* portable code must never pass more than 32 bytes */
3971 #define SPI_BUFSIZ      max(32, SMP_CACHE_BYTES)
3972
3973 static u8       *buf;
3974
3975 /**
3976  * spi_write_then_read - SPI synchronous write followed by read
3977  * @spi: device with which data will be exchanged
3978  * @txbuf: data to be written (need not be dma-safe)
3979  * @n_tx: size of txbuf, in bytes
3980  * @rxbuf: buffer into which data will be read (need not be dma-safe)
3981  * @n_rx: size of rxbuf, in bytes
3982  * Context: can sleep
3983  *
3984  * This performs a half duplex MicroWire style transaction with the
3985  * device, sending txbuf and then reading rxbuf.  The return value
3986  * is zero for success, else a negative errno status code.
3987  * This call may only be used from a context that may sleep.
3988  *
3989  * Parameters to this routine are always copied using a small buffer.
3990  * Performance-sensitive or bulk transfer code should instead use
3991  * spi_{async,sync}() calls with dma-safe buffers.
3992  *
3993  * Return: zero on success, else a negative error code.
3994  */
3995 int spi_write_then_read(struct spi_device *spi,
3996                 const void *txbuf, unsigned n_tx,
3997                 void *rxbuf, unsigned n_rx)
3998 {
3999         static DEFINE_MUTEX(lock);
4000
4001         int                     status;
4002         struct spi_message      message;
4003         struct spi_transfer     x[2];
4004         u8                      *local_buf;
4005
4006         /* Use preallocated DMA-safe buffer if we can.  We can't avoid
4007          * copying here, (as a pure convenience thing), but we can
4008          * keep heap costs out of the hot path unless someone else is
4009          * using the pre-allocated buffer or the transfer is too large.
4010          */
4011         if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
4012                 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
4013                                     GFP_KERNEL | GFP_DMA);
4014                 if (!local_buf)
4015                         return -ENOMEM;
4016         } else {
4017                 local_buf = buf;
4018         }
4019
4020         spi_message_init(&message);
4021         memset(x, 0, sizeof(x));
4022         if (n_tx) {
4023                 x[0].len = n_tx;
4024                 spi_message_add_tail(&x[0], &message);
4025         }
4026         if (n_rx) {
4027                 x[1].len = n_rx;
4028                 spi_message_add_tail(&x[1], &message);
4029         }
4030
4031         memcpy(local_buf, txbuf, n_tx);
4032         x[0].tx_buf = local_buf;
4033         x[1].rx_buf = local_buf + n_tx;
4034
4035         /* do the i/o */
4036         status = spi_sync(spi, &message);
4037         if (status == 0)
4038                 memcpy(rxbuf, x[1].rx_buf, n_rx);
4039
4040         if (x[0].tx_buf == buf)
4041                 mutex_unlock(&lock);
4042         else
4043                 kfree(local_buf);
4044
4045         return status;
4046 }
4047 EXPORT_SYMBOL_GPL(spi_write_then_read);
4048
4049 /*-------------------------------------------------------------------------*/
4050
4051 #if IS_ENABLED(CONFIG_OF)
4052 /* must call put_device() when done with returned spi_device device */
4053 struct spi_device *of_find_spi_device_by_node(struct device_node *node)
4054 {
4055         struct device *dev = bus_find_device_by_of_node(&spi_bus_type, node);
4056
4057         return dev ? to_spi_device(dev) : NULL;
4058 }
4059 EXPORT_SYMBOL_GPL(of_find_spi_device_by_node);
4060 #endif /* IS_ENABLED(CONFIG_OF) */
4061
4062 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
4063 /* the spi controllers are not using spi_bus, so we find it with another way */
4064 static struct spi_controller *of_find_spi_controller_by_node(struct device_node *node)
4065 {
4066         struct device *dev;
4067
4068         dev = class_find_device_by_of_node(&spi_master_class, node);
4069         if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
4070                 dev = class_find_device_by_of_node(&spi_slave_class, node);
4071         if (!dev)
4072                 return NULL;
4073
4074         /* reference got in class_find_device */
4075         return container_of(dev, struct spi_controller, dev);
4076 }
4077
4078 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
4079                          void *arg)
4080 {
4081         struct of_reconfig_data *rd = arg;
4082         struct spi_controller *ctlr;
4083         struct spi_device *spi;
4084
4085         switch (of_reconfig_get_state_change(action, arg)) {
4086         case OF_RECONFIG_CHANGE_ADD:
4087                 ctlr = of_find_spi_controller_by_node(rd->dn->parent);
4088                 if (ctlr == NULL)
4089                         return NOTIFY_OK;       /* not for us */
4090
4091                 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
4092                         put_device(&ctlr->dev);
4093                         return NOTIFY_OK;
4094                 }
4095
4096                 spi = of_register_spi_device(ctlr, rd->dn);
4097                 put_device(&ctlr->dev);
4098
4099                 if (IS_ERR(spi)) {
4100                         pr_err("%s: failed to create for '%pOF'\n",
4101                                         __func__, rd->dn);
4102                         of_node_clear_flag(rd->dn, OF_POPULATED);
4103                         return notifier_from_errno(PTR_ERR(spi));
4104                 }
4105                 break;
4106
4107         case OF_RECONFIG_CHANGE_REMOVE:
4108                 /* already depopulated? */
4109                 if (!of_node_check_flag(rd->dn, OF_POPULATED))
4110                         return NOTIFY_OK;
4111
4112                 /* find our device by node */
4113                 spi = of_find_spi_device_by_node(rd->dn);
4114                 if (spi == NULL)
4115                         return NOTIFY_OK;       /* no? not meant for us */
4116
4117                 /* unregister takes one ref away */
4118                 spi_unregister_device(spi);
4119
4120                 /* and put the reference of the find */
4121                 put_device(&spi->dev);
4122                 break;
4123         }
4124
4125         return NOTIFY_OK;
4126 }
4127
4128 static struct notifier_block spi_of_notifier = {
4129         .notifier_call = of_spi_notify,
4130 };
4131 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
4132 extern struct notifier_block spi_of_notifier;
4133 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
4134
4135 #if IS_ENABLED(CONFIG_ACPI)
4136 static int spi_acpi_controller_match(struct device *dev, const void *data)
4137 {
4138         return ACPI_COMPANION(dev->parent) == data;
4139 }
4140
4141 static struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev)
4142 {
4143         struct device *dev;
4144
4145         dev = class_find_device(&spi_master_class, NULL, adev,
4146                                 spi_acpi_controller_match);
4147         if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
4148                 dev = class_find_device(&spi_slave_class, NULL, adev,
4149                                         spi_acpi_controller_match);
4150         if (!dev)
4151                 return NULL;
4152
4153         return container_of(dev, struct spi_controller, dev);
4154 }
4155
4156 static struct spi_device *acpi_spi_find_device_by_adev(struct acpi_device *adev)
4157 {
4158         struct device *dev;
4159
4160         dev = bus_find_device_by_acpi_dev(&spi_bus_type, adev);
4161         return to_spi_device(dev);
4162 }
4163
4164 static int acpi_spi_notify(struct notifier_block *nb, unsigned long value,
4165                            void *arg)
4166 {
4167         struct acpi_device *adev = arg;
4168         struct spi_controller *ctlr;
4169         struct spi_device *spi;
4170
4171         switch (value) {
4172         case ACPI_RECONFIG_DEVICE_ADD:
4173                 ctlr = acpi_spi_find_controller_by_adev(adev->parent);
4174                 if (!ctlr)
4175                         break;
4176
4177                 acpi_register_spi_device(ctlr, adev);
4178                 put_device(&ctlr->dev);
4179                 break;
4180         case ACPI_RECONFIG_DEVICE_REMOVE:
4181                 if (!acpi_device_enumerated(adev))
4182                         break;
4183
4184                 spi = acpi_spi_find_device_by_adev(adev);
4185                 if (!spi)
4186                         break;
4187
4188                 spi_unregister_device(spi);
4189                 put_device(&spi->dev);
4190                 break;
4191         }
4192
4193         return NOTIFY_OK;
4194 }
4195
4196 static struct notifier_block spi_acpi_notifier = {
4197         .notifier_call = acpi_spi_notify,
4198 };
4199 #else
4200 extern struct notifier_block spi_acpi_notifier;
4201 #endif
4202
4203 static int __init spi_init(void)
4204 {
4205         int     status;
4206
4207         buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
4208         if (!buf) {
4209                 status = -ENOMEM;
4210                 goto err0;
4211         }
4212
4213         status = bus_register(&spi_bus_type);
4214         if (status < 0)
4215                 goto err1;
4216
4217         status = class_register(&spi_master_class);
4218         if (status < 0)
4219                 goto err2;
4220
4221         if (IS_ENABLED(CONFIG_SPI_SLAVE)) {
4222                 status = class_register(&spi_slave_class);
4223                 if (status < 0)
4224                         goto err3;
4225         }
4226
4227         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
4228                 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
4229         if (IS_ENABLED(CONFIG_ACPI))
4230                 WARN_ON(acpi_reconfig_notifier_register(&spi_acpi_notifier));
4231
4232         return 0;
4233
4234 err3:
4235         class_unregister(&spi_master_class);
4236 err2:
4237         bus_unregister(&spi_bus_type);
4238 err1:
4239         kfree(buf);
4240         buf = NULL;
4241 err0:
4242         return status;
4243 }
4244
4245 /* board_info is normally registered in arch_initcall(),
4246  * but even essential drivers wait till later
4247  *
4248  * REVISIT only boardinfo really needs static linking. the rest (device and
4249  * driver registration) _could_ be dynamically linked (modular) ... costs
4250  * include needing to have boardinfo data structures be much more public.
4251  */
4252 postcore_initcall(spi_init);