drivers/nvmem/core.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * nvmem framework core.
   4  *
   5  * Copyright (C) 2015 Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
   6  * Copyright (C) 2013 Maxime Ripard <maxime.ripard@free-electrons.com>
   7  */
   8
   9 #include <linux/device.h>
  10 #include <linux/export.h>
  11 #include <linux/fs.h>
  12 #include <linux/idr.h>
  13 #include <linux/init.h>
  14 #include <linux/kref.h>
  15 #include <linux/module.h>
  16 #include <linux/nvmem-consumer.h>
  17 #include <linux/nvmem-provider.h>
  18 #include <linux/gpio/consumer.h>
  19 #include <linux/of.h>
  20 #include <linux/slab.h>
  21
  22 struct nvmem_device {
  23         struct module           *owner;
  24         struct device           dev;
  25         int                     stride;
  26         int                     word_size;
  27         int                     id;
  28         struct kref             refcnt;
  29         size_t                  size;
  30         bool                    read_only;
  31         bool                    root_only;
  32         int                     flags;
  33         enum nvmem_type         type;
  34         struct bin_attribute    eeprom;
  35         struct device           *base_dev;
  36         struct list_head        cells;
  37         const struct nvmem_keepout *keepout;
  38         unsigned int            nkeepout;
  39         nvmem_reg_read_t        reg_read;
  40         nvmem_reg_write_t       reg_write;
  41         nvmem_cell_post_process_t cell_post_process;
  42         struct gpio_desc        *wp_gpio;
  43         void *priv;
  44 };
  45
  46 #define to_nvmem_device(d) container_of(d, struct nvmem_device, dev)
  47
  48 #define FLAG_COMPAT             BIT(0)
  49 struct nvmem_cell_entry {
  50         const char              *name;
  51         int                     offset;
  52         int                     bytes;
  53         int                     bit_offset;
  54         int                     nbits;
  55         struct device_node      *np;
  56         struct nvmem_device     *nvmem;
  57         struct list_head        node;
  58 };
  59
  60 struct nvmem_cell {
  61         struct nvmem_cell_entry *entry;
  62         const char              *id;
  63 };
  64
  65 static DEFINE_MUTEX(nvmem_mutex);
  66 static DEFINE_IDA(nvmem_ida);
  67
  68 static DEFINE_MUTEX(nvmem_cell_mutex);
  69 static LIST_HEAD(nvmem_cell_tables);
  70
  71 static DEFINE_MUTEX(nvmem_lookup_mutex);
  72 static LIST_HEAD(nvmem_lookup_list);
  73
  74 static BLOCKING_NOTIFIER_HEAD(nvmem_notifier);
  75
  76 static int __nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset,
  77                             void *val, size_t bytes)
  78 {
  79         if (nvmem->reg_read)
  80                 return nvmem->reg_read(nvmem->priv, offset, val, bytes);
  81
  82         return -EINVAL;
  83 }
  84
  85 static int __nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset,
  86                              void *val, size_t bytes)
  87 {
  88         int ret;
  89
  90         if (nvmem->reg_write) {
  91                 gpiod_set_value_cansleep(nvmem->wp_gpio, 0);
  92                 ret = nvmem->reg_write(nvmem->priv, offset, val, bytes);
  93                 gpiod_set_value_cansleep(nvmem->wp_gpio, 1);
  94                 return ret;
  95         }
  96
  97         return -EINVAL;
  98 }
  99
 100 static int nvmem_access_with_keepouts(struct nvmem_device *nvmem,
 101                                       unsigned int offset, void *val,
 102                                       size_t bytes, int write)
 103 {
 104
 105         unsigned int end = offset + bytes;
 106         unsigned int kend, ksize;
 107         const struct nvmem_keepout *keepout = nvmem->keepout;
 108         const struct nvmem_keepout *keepoutend = keepout + nvmem->nkeepout;
 109         int rc;
 110
 111         /*
 112          * Skip all keepouts before the range being accessed.
 113          * Keepouts are sorted.
 114          */
 115         while ((keepout < keepoutend) && (keepout->end <= offset))
 116                 keepout++;
 117
 118         while ((offset < end) && (keepout < keepoutend)) {
 119                 /* Access the valid portion before the keepout. */
 120                 if (offset < keepout->start) {
 121                         kend = min(end, keepout->start);
 122                         ksize = kend - offset;
 123                         if (write)
 124                                 rc = __nvmem_reg_write(nvmem, offset, val, ksize);
 125                         else
 126                                 rc = __nvmem_reg_read(nvmem, offset, val, ksize);
 127
 128                         if (rc)
 129                                 return rc;
 130
 131                         offset += ksize;
 132                         val += ksize;
 133                 }
 134
 135                 /*
 136                  * Now we're aligned to the start of this keepout zone. Go
 137                  * through it.
 138                  */
 139                 kend = min(end, keepout->end);
 140                 ksize = kend - offset;
 141                 if (!write)
 142                         memset(val, keepout->value, ksize);
 143
 144                 val += ksize;
 145                 offset += ksize;
 146                 keepout++;
 147         }
 148
 149         /*
 150          * If we ran out of keepouts but there's still stuff to do, send it
 151          * down directly
 152          */
 153         if (offset < end) {
 154                 ksize = end - offset;
 155                 if (write)
 156                         return __nvmem_reg_write(nvmem, offset, val, ksize);
 157                 else
 158                         return __nvmem_reg_read(nvmem, offset, val, ksize);
 159         }
 160
 161         return 0;
 162 }
 163
 164 static int nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset,
 165                           void *val, size_t bytes)
 166 {
 167         if (!nvmem->nkeepout)
 168                 return __nvmem_reg_read(nvmem, offset, val, bytes);
 169
 170         return nvmem_access_with_keepouts(nvmem, offset, val, bytes, false);
 171 }
 172
 173 static int nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset,
 174                            void *val, size_t bytes)
 175 {
 176         if (!nvmem->nkeepout)
 177                 return __nvmem_reg_write(nvmem, offset, val, bytes);
 178
 179         return nvmem_access_with_keepouts(nvmem, offset, val, bytes, true);
 180 }
 181
 182 #ifdef CONFIG_NVMEM_SYSFS
 183 static const char * const nvmem_type_str[] = {
 184         [NVMEM_TYPE_UNKNOWN] = "Unknown",
 185         [NVMEM_TYPE_EEPROM] = "EEPROM",
 186         [NVMEM_TYPE_OTP] = "OTP",
 187         [NVMEM_TYPE_BATTERY_BACKED] = "Battery backed",
 188         [NVMEM_TYPE_FRAM] = "FRAM",
 189 };
 190
 191 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 192 static struct lock_class_key eeprom_lock_key;
 193 #endif
 194
 195 static ssize_t type_show(struct device *dev,
 196                          struct device_attribute *attr, char *buf)
 197 {
 198         struct nvmem_device *nvmem = to_nvmem_device(dev);
 199
 200         return sprintf(buf, "%s\n", nvmem_type_str[nvmem->type]);
 201 }
 202
 203 static DEVICE_ATTR_RO(type);
 204
 205 static struct attribute *nvmem_attrs[] = {
 206         &dev_attr_type.attr,
 207         NULL,
 208 };
 209
 210 static ssize_t bin_attr_nvmem_read(struct file *filp, struct kobject *kobj,
 211                                    struct bin_attribute *attr, char *buf,
 212                                    loff_t pos, size_t count)
 213 {
 214         struct device *dev;
 215         struct nvmem_device *nvmem;
 216         int rc;
 217
 218         if (attr->private)
 219                 dev = attr->private;
 220         else
 221                 dev = kobj_to_dev(kobj);
 222         nvmem = to_nvmem_device(dev);
 223
 224         /* Stop the user from reading */
 225         if (pos >= nvmem->size)
 226                 return 0;
 227
 228         if (!IS_ALIGNED(pos, nvmem->stride))
 229                 return -EINVAL;
 230
 231         if (count < nvmem->word_size)
 232                 return -EINVAL;
 233
 234         if (pos + count > nvmem->size)
 235                 count = nvmem->size - pos;
 236
 237         count = round_down(count, nvmem->word_size);
 238
 239         if (!nvmem->reg_read)
 240                 return -EPERM;
 241
 242         rc = nvmem_reg_read(nvmem, pos, buf, count);
 243
 244         if (rc)
 245                 return rc;
 246
 247         return count;
 248 }
 249
 250 static ssize_t bin_attr_nvmem_write(struct file *filp, struct kobject *kobj,
 251                                     struct bin_attribute *attr, char *buf,
 252                                     loff_t pos, size_t count)
 253 {
 254         struct device *dev;
 255         struct nvmem_device *nvmem;
 256         int rc;
 257
 258         if (attr->private)
 259                 dev = attr->private;
 260         else
 261                 dev = kobj_to_dev(kobj);
 262         nvmem = to_nvmem_device(dev);
 263
 264         /* Stop the user from writing */
 265         if (pos >= nvmem->size)
 266                 return -EFBIG;
 267
 268         if (!IS_ALIGNED(pos, nvmem->stride))
 269                 return -EINVAL;
 270
 271         if (count < nvmem->word_size)
 272                 return -EINVAL;
 273
 274         if (pos + count > nvmem->size)
 275                 count = nvmem->size - pos;
 276
 277         count = round_down(count, nvmem->word_size);
 278
 279         if (!nvmem->reg_write)
 280                 return -EPERM;
 281
 282         rc = nvmem_reg_write(nvmem, pos, buf, count);
 283
 284         if (rc)
 285                 return rc;
 286
 287         return count;
 288 }
 289
 290 static umode_t nvmem_bin_attr_get_umode(struct nvmem_device *nvmem)
 291 {
 292         umode_t mode = 0400;
 293
 294         if (!nvmem->root_only)
 295                 mode |= 0044;
 296
 297         if (!nvmem->read_only)
 298                 mode |= 0200;
 299
 300         if (!nvmem->reg_write)
 301                 mode &= ~0200;
 302
 303         if (!nvmem->reg_read)
 304                 mode &= ~0444;
 305
 306         return mode;
 307 }
 308
 309 static umode_t nvmem_bin_attr_is_visible(struct kobject *kobj,
 310                                          struct bin_attribute *attr, int i)
 311 {
 312         struct device *dev = kobj_to_dev(kobj);
 313         struct nvmem_device *nvmem = to_nvmem_device(dev);
 314
 315         attr->size = nvmem->size;
 316
 317         return nvmem_bin_attr_get_umode(nvmem);
 318 }
 319
 320 /* default read/write permissions */
 321 static struct bin_attribute bin_attr_rw_nvmem = {
 322         .attr   = {
 323                 .name   = "nvmem",
 324                 .mode   = 0644,
 325         },
 326         .read   = bin_attr_nvmem_read,
 327         .write  = bin_attr_nvmem_write,
 328 };
 329
 330 static struct bin_attribute *nvmem_bin_attributes[] = {
 331         &bin_attr_rw_nvmem,
 332         NULL,
 333 };
 334
 335 static const struct attribute_group nvmem_bin_group = {
 336         .bin_attrs      = nvmem_bin_attributes,
 337         .attrs          = nvmem_attrs,
 338         .is_bin_visible = nvmem_bin_attr_is_visible,
 339 };
 340
 341 static const struct attribute_group *nvmem_dev_groups[] = {
 342         &nvmem_bin_group,
 343         NULL,
 344 };
 345
 346 static struct bin_attribute bin_attr_nvmem_eeprom_compat = {
 347         .attr   = {
 348                 .name   = "eeprom",
 349         },
 350         .read   = bin_attr_nvmem_read,
 351         .write  = bin_attr_nvmem_write,
 352 };
 353
 354 /*
 355  * nvmem_setup_compat() - Create an additional binary entry in
 356  * drivers sys directory, to be backwards compatible with the older
 357  * drivers/misc/eeprom drivers.
 358  */
 359 static int nvmem_sysfs_setup_compat(struct nvmem_device *nvmem,
 360                                     const struct nvmem_config *config)
 361 {
 362         int rval;
 363
 364         if (!config->compat)
 365                 return 0;
 366
 367         if (!config->base_dev)
 368                 return -EINVAL;
 369
 370         if (config->type == NVMEM_TYPE_FRAM)
 371                 bin_attr_nvmem_eeprom_compat.attr.name = "fram";
 372
 373         nvmem->eeprom = bin_attr_nvmem_eeprom_compat;
 374         nvmem->eeprom.attr.mode = nvmem_bin_attr_get_umode(nvmem);
 375         nvmem->eeprom.size = nvmem->size;
 376 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 377         nvmem->eeprom.attr.key = &eeprom_lock_key;
 378 #endif
 379         nvmem->eeprom.private = &nvmem->dev;
 380         nvmem->base_dev = config->base_dev;
 381
 382         rval = device_create_bin_file(nvmem->base_dev, &nvmem->eeprom);
 383         if (rval) {
 384                 dev_err(&nvmem->dev,
 385                         "Failed to create eeprom binary file %d\n", rval);
 386                 return rval;
 387         }
 388
 389         nvmem->flags |= FLAG_COMPAT;
 390
 391         return 0;
 392 }
 393
 394 static void nvmem_sysfs_remove_compat(struct nvmem_device *nvmem,
 395                               const struct nvmem_config *config)
 396 {
 397         if (config->compat)
 398                 device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom);
 399 }
 400
 401 #else /* CONFIG_NVMEM_SYSFS */
 402
 403 static int nvmem_sysfs_setup_compat(struct nvmem_device *nvmem,
 404                                     const struct nvmem_config *config)
 405 {
 406         return -ENOSYS;
 407 }
 408 static void nvmem_sysfs_remove_compat(struct nvmem_device *nvmem,
 409                                       const struct nvmem_config *config)
 410 {
 411 }
 412
 413 #endif /* CONFIG_NVMEM_SYSFS */
 414
 415 static void nvmem_release(struct device *dev)
 416 {
 417         struct nvmem_device *nvmem = to_nvmem_device(dev);
 418
 419         ida_free(&nvmem_ida, nvmem->id);
 420         gpiod_put(nvmem->wp_gpio);
 421         kfree(nvmem);
 422 }
 423
 424 static const struct device_type nvmem_provider_type = {
 425         .release        = nvmem_release,
 426 };
 427
 428 static struct bus_type nvmem_bus_type = {
 429         .name           = "nvmem",
 430 };
 431
 432 static void nvmem_cell_entry_drop(struct nvmem_cell_entry *cell)
 433 {
 434         blocking_notifier_call_chain(&nvmem_notifier, NVMEM_CELL_REMOVE, cell);
 435         mutex_lock(&nvmem_mutex);
 436         list_del(&cell->node);
 437         mutex_unlock(&nvmem_mutex);
 438         of_node_put(cell->np);
 439         kfree_const(cell->name);
 440         kfree(cell);
 441 }
 442
 443 static void nvmem_device_remove_all_cells(const struct nvmem_device *nvmem)
 444 {
 445         struct nvmem_cell_entry *cell, *p;
 446
 447         list_for_each_entry_safe(cell, p, &nvmem->cells, node)
 448                 nvmem_cell_entry_drop(cell);
 449 }
 450
 451 static void nvmem_cell_entry_add(struct nvmem_cell_entry *cell)
 452 {
 453         mutex_lock(&nvmem_mutex);
 454         list_add_tail(&cell->node, &cell->nvmem->cells);
 455         mutex_unlock(&nvmem_mutex);
 456         blocking_notifier_call_chain(&nvmem_notifier, NVMEM_CELL_ADD, cell);
 457 }
 458
 459 static int nvmem_cell_info_to_nvmem_cell_entry_nodup(struct nvmem_device *nvmem,
 460                                                      const struct nvmem_cell_info *info,
 461                                                      struct nvmem_cell_entry *cell)
 462 {
 463         cell->nvmem = nvmem;
 464         cell->offset = info->offset;
 465         cell->bytes = info->bytes;
 466         cell->name = info->name;
 467
 468         cell->bit_offset = info->bit_offset;
 469         cell->nbits = info->nbits;
 470         cell->np = info->np;
 471
 472         if (cell->nbits)
 473                 cell->bytes = DIV_ROUND_UP(cell->nbits + cell->bit_offset,
 474                                            BITS_PER_BYTE);
 475
 476         if (!IS_ALIGNED(cell->offset, nvmem->stride)) {
 477                 dev_err(&nvmem->dev,
 478                         "cell %s unaligned to nvmem stride %d\n",
 479                         cell->name ?: "<unknown>", nvmem->stride);
 480                 return -EINVAL;
 481         }
 482
 483         return 0;
 484 }
 485
 486 static int nvmem_cell_info_to_nvmem_cell_entry(struct nvmem_device *nvmem,
 487                                                const struct nvmem_cell_info *info,
 488                                                struct nvmem_cell_entry *cell)
 489 {
 490         int err;
 491
 492         err = nvmem_cell_info_to_nvmem_cell_entry_nodup(nvmem, info, cell);
 493         if (err)
 494                 return err;
 495
 496         cell->name = kstrdup_const(info->name, GFP_KERNEL);
 497         if (!cell->name)
 498                 return -ENOMEM;
 499
 500         return 0;
 501 }
 502
 503 /**
 504  * nvmem_add_cells() - Add cell information to an nvmem device
 505  *
 506  * @nvmem: nvmem device to add cells to.
 507  * @info: nvmem cell info to add to the device
 508  * @ncells: number of cells in info
 509  *
 510  * Return: 0 or negative error code on failure.
 511  */
 512 static int nvmem_add_cells(struct nvmem_device *nvmem,
 513                     const struct nvmem_cell_info *info,
 514                     int ncells)
 515 {
 516         struct nvmem_cell_entry **cells;
 517         int i, rval;
 518
 519         cells = kcalloc(ncells, sizeof(*cells), GFP_KERNEL);
 520         if (!cells)
 521                 return -ENOMEM;
 522
 523         for (i = 0; i < ncells; i++) {
 524                 cells[i] = kzalloc(sizeof(**cells), GFP_KERNEL);
 525                 if (!cells[i]) {
 526                         rval = -ENOMEM;
 527                         goto err;
 528                 }
 529
 530                 rval = nvmem_cell_info_to_nvmem_cell_entry(nvmem, &info[i], cells[i]);
 531                 if (rval) {
 532                         kfree(cells[i]);
 533                         goto err;
 534                 }
 535
 536                 nvmem_cell_entry_add(cells[i]);
 537         }
 538
 539         /* remove tmp array */
 540         kfree(cells);
 541
 542         return 0;
 543 err:
 544         while (i--)
 545                 nvmem_cell_entry_drop(cells[i]);
 546
 547         kfree(cells);
 548
 549         return rval;
 550 }
 551
 552 /**
 553  * nvmem_register_notifier() - Register a notifier block for nvmem events.
 554  *
 555  * @nb: notifier block to be called on nvmem events.
 556  *
 557  * Return: 0 on success, negative error number on failure.
 558  */
 559 int nvmem_register_notifier(struct notifier_block *nb)
 560 {
 561         return blocking_notifier_chain_register(&nvmem_notifier, nb);
 562 }
 563 EXPORT_SYMBOL_GPL(nvmem_register_notifier);
 564
 565 /**
 566  * nvmem_unregister_notifier() - Unregister a notifier block for nvmem events.
 567  *
 568  * @nb: notifier block to be unregistered.
 569  *
 570  * Return: 0 on success, negative error number on failure.
 571  */
 572 int nvmem_unregister_notifier(struct notifier_block *nb)
 573 {
 574         return blocking_notifier_chain_unregister(&nvmem_notifier, nb);
 575 }
 576 EXPORT_SYMBOL_GPL(nvmem_unregister_notifier);
 577
 578 static int nvmem_add_cells_from_table(struct nvmem_device *nvmem)
 579 {
 580         const struct nvmem_cell_info *info;
 581         struct nvmem_cell_table *table;
 582         struct nvmem_cell_entry *cell;
 583         int rval = 0, i;
 584
 585         mutex_lock(&nvmem_cell_mutex);
 586         list_for_each_entry(table, &nvmem_cell_tables, node) {
 587                 if (strcmp(nvmem_dev_name(nvmem), table->nvmem_name) == 0) {
 588                         for (i = 0; i < table->ncells; i++) {
 589                                 info = &table->cells[i];
 590
 591                                 cell = kzalloc(sizeof(*cell), GFP_KERNEL);
 592                                 if (!cell) {
 593                                         rval = -ENOMEM;
 594                                         goto out;
 595                                 }
 596
 597                                 rval = nvmem_cell_info_to_nvmem_cell_entry(nvmem, info, cell);
 598                                 if (rval) {
 599                                         kfree(cell);
 600                                         goto out;
 601                                 }
 602
 603                                 nvmem_cell_entry_add(cell);
 604                         }
 605                 }
 606         }
 607
 608 out:
 609         mutex_unlock(&nvmem_cell_mutex);
 610         return rval;
 611 }
 612
 613 static struct nvmem_cell_entry *
 614 nvmem_find_cell_entry_by_name(struct nvmem_device *nvmem, const char *cell_id)
 615 {
 616         struct nvmem_cell_entry *iter, *cell = NULL;
 617
 618         mutex_lock(&nvmem_mutex);
 619         list_for_each_entry(iter, &nvmem->cells, node) {
 620                 if (strcmp(cell_id, iter->name) == 0) {
 621                         cell = iter;
 622                         break;
 623                 }
 624         }
 625         mutex_unlock(&nvmem_mutex);
 626
 627         return cell;
 628 }
 629
 630 static int nvmem_validate_keepouts(struct nvmem_device *nvmem)
 631 {
 632         unsigned int cur = 0;
 633         const struct nvmem_keepout *keepout = nvmem->keepout;
 634         const struct nvmem_keepout *keepoutend = keepout + nvmem->nkeepout;
 635
 636         while (keepout < keepoutend) {
 637                 /* Ensure keepouts are sorted and don't overlap. */
 638                 if (keepout->start < cur) {
 639                         dev_err(&nvmem->dev,
 640                                 "Keepout regions aren't sorted or overlap.\n");
 641
 642                         return -ERANGE;
 643                 }
 644
 645                 if (keepout->end < keepout->start) {
 646                         dev_err(&nvmem->dev,
 647                                 "Invalid keepout region.\n");
 648
 649                         return -EINVAL;
 650                 }
 651
 652                 /*
 653                  * Validate keepouts (and holes between) don't violate
 654                  * word_size constraints.
 655                  */
 656                 if ((keepout->end - keepout->start < nvmem->word_size) ||
 657                     ((keepout->start != cur) &&
 658                      (keepout->start - cur < nvmem->word_size))) {
 659
 660                         dev_err(&nvmem->dev,
 661                                 "Keepout regions violate word_size constraints.\n");
 662
 663                         return -ERANGE;
 664                 }
 665
 666                 /* Validate keepouts don't violate stride (alignment). */
 667                 if (!IS_ALIGNED(keepout->start, nvmem->stride) ||
 668                     !IS_ALIGNED(keepout->end, nvmem->stride)) {
 669
 670                         dev_err(&nvmem->dev,
 671                                 "Keepout regions violate stride.\n");
 672
 673                         return -EINVAL;
 674                 }
 675
 676                 cur = keepout->end;
 677                 keepout++;
 678         }
 679
 680         return 0;
 681 }
 682
 683 static int nvmem_add_cells_from_of(struct nvmem_device *nvmem)
 684 {
 685         struct device_node *parent, *child;
 686         struct device *dev = &nvmem->dev;
 687         struct nvmem_cell_entry *cell;
 688         const __be32 *addr;
 689         int len;
 690
 691         parent = dev->of_node;
 692
 693         for_each_child_of_node(parent, child) {
 694                 addr = of_get_property(child, "reg", &len);
 695                 if (!addr)
 696                         continue;
 697                 if (len < 2 * sizeof(u32)) {
 698                         dev_err(dev, "nvmem: invalid reg on %pOF\n", child);
 699                         of_node_put(child);
 700                         return -EINVAL;
 701                 }
 702
 703                 cell = kzalloc(sizeof(*cell), GFP_KERNEL);
 704                 if (!cell) {
 705                         of_node_put(child);
 706                         return -ENOMEM;
 707                 }
 708
 709                 cell->nvmem = nvmem;
 710                 cell->offset = be32_to_cpup(addr++);
 711                 cell->bytes = be32_to_cpup(addr);
 712                 cell->name = kasprintf(GFP_KERNEL, "%pOFn", child);
 713
 714                 addr = of_get_property(child, "bits", &len);
 715                 if (addr && len == (2 * sizeof(u32))) {
 716                         cell->bit_offset = be32_to_cpup(addr++);
 717                         cell->nbits = be32_to_cpup(addr);
 718                 }
 719
 720                 if (cell->nbits)
 721                         cell->bytes = DIV_ROUND_UP(
 722                                         cell->nbits + cell->bit_offset,
 723                                         BITS_PER_BYTE);
 724
 725                 if (!IS_ALIGNED(cell->offset, nvmem->stride)) {
 726                         dev_err(dev, "cell %s unaligned to nvmem stride %d\n",
 727                                 cell->name, nvmem->stride);
 728                         /* Cells already added will be freed later. */
 729                         kfree_const(cell->name);
 730                         kfree(cell);
 731                         of_node_put(child);
 732                         return -EINVAL;
 733                 }
 734
 735                 cell->np = of_node_get(child);
 736                 nvmem_cell_entry_add(cell);
 737         }
 738
 739         return 0;
 740 }
 741
 742 /**
 743  * nvmem_register() - Register a nvmem device for given nvmem_config.
 744  * Also creates a binary entry in /sys/bus/nvmem/devices/dev-name/nvmem
 745  *
 746  * @config: nvmem device configuration with which nvmem device is created.
 747  *
 748  * Return: Will be an ERR_PTR() on error or a valid pointer to nvmem_device
 749  * on success.
 750  */
 751
 752 struct nvmem_device *nvmem_register(const struct nvmem_config *config)
 753 {
 754         struct nvmem_device *nvmem;
 755         int rval;
 756
 757         if (!config->dev)
 758                 return ERR_PTR(-EINVAL);
 759
 760         if (!config->reg_read && !config->reg_write)
 761                 return ERR_PTR(-EINVAL);
 762
 763         nvmem = kzalloc(sizeof(*nvmem), GFP_KERNEL);
 764         if (!nvmem)
 765                 return ERR_PTR(-ENOMEM);
 766
 767         rval  = ida_alloc(&nvmem_ida, GFP_KERNEL);
 768         if (rval < 0) {
 769                 kfree(nvmem);
 770                 return ERR_PTR(rval);
 771         }
 772
 773         if (config->wp_gpio)
 774                 nvmem->wp_gpio = config->wp_gpio;
 775         else if (!config->ignore_wp)
 776                 nvmem->wp_gpio = gpiod_get_optional(config->dev, "wp",
 777                                                     GPIOD_OUT_HIGH);
 778         if (IS_ERR(nvmem->wp_gpio)) {
 779                 ida_free(&nvmem_ida, nvmem->id);
 780                 rval = PTR_ERR(nvmem->wp_gpio);
 781                 kfree(nvmem);
 782                 return ERR_PTR(rval);
 783         }
 784
 785         kref_init(&nvmem->refcnt);
 786         INIT_LIST_HEAD(&nvmem->cells);
 787
 788         nvmem->id = rval;
 789         nvmem->owner = config->owner;
 790         if (!nvmem->owner && config->dev->driver)
 791                 nvmem->owner = config->dev->driver->owner;
 792         nvmem->stride = config->stride ?: 1;
 793         nvmem->word_size = config->word_size ?: 1;
 794         nvmem->size = config->size;
 795         nvmem->dev.type = &nvmem_provider_type;
 796         nvmem->dev.bus = &nvmem_bus_type;
 797         nvmem->dev.parent = config->dev;
 798         nvmem->root_only = config->root_only;
 799         nvmem->priv = config->priv;
 800         nvmem->type = config->type;
 801         nvmem->reg_read = config->reg_read;
 802         nvmem->reg_write = config->reg_write;
 803         nvmem->cell_post_process = config->cell_post_process;
 804         nvmem->keepout = config->keepout;
 805         nvmem->nkeepout = config->nkeepout;
 806         if (config->of_node)
 807                 nvmem->dev.of_node = config->of_node;
 808         else if (!config->no_of_node)
 809                 nvmem->dev.of_node = config->dev->of_node;
 810
 811         switch (config->id) {
 812         case NVMEM_DEVID_NONE:
 813                 dev_set_name(&nvmem->dev, "%s", config->name);
 814                 break;
 815         case NVMEM_DEVID_AUTO:
 816                 dev_set_name(&nvmem->dev, "%s%d", config->name, nvmem->id);
 817                 break;
 818         default:
 819                 dev_set_name(&nvmem->dev, "%s%d",
 820                              config->name ? : "nvmem",
 821                              config->name ? config->id : nvmem->id);
 822                 break;
 823         }
 824
 825         nvmem->read_only = device_property_present(config->dev, "read-only") ||
 826                            config->read_only || !nvmem->reg_write;
 827
 828 #ifdef CONFIG_NVMEM_SYSFS
 829         nvmem->dev.groups = nvmem_dev_groups;
 830 #endif
 831
 832         if (nvmem->nkeepout) {
 833                 rval = nvmem_validate_keepouts(nvmem);
 834                 if (rval) {
 835                         ida_free(&nvmem_ida, nvmem->id);
 836                         kfree(nvmem);
 837                         return ERR_PTR(rval);
 838                 }
 839         }
 840
 841         dev_dbg(&nvmem->dev, "Registering nvmem device %s\n", config->name);
 842
 843         rval = device_register(&nvmem->dev);
 844         if (rval)
 845                 goto err_put_device;
 846
 847         if (config->compat) {
 848                 rval = nvmem_sysfs_setup_compat(nvmem, config);
 849                 if (rval)
 850                         goto err_device_del;
 851         }
 852
 853         if (config->cells) {
 854                 rval = nvmem_add_cells(nvmem, config->cells, config->ncells);
 855                 if (rval)
 856                         goto err_teardown_compat;
 857         }
 858
 859         rval = nvmem_add_cells_from_table(nvmem);
 860         if (rval)
 861                 goto err_remove_cells;
 862
 863         rval = nvmem_add_cells_from_of(nvmem);
 864         if (rval)
 865                 goto err_remove_cells;
 866
 867         blocking_notifier_call_chain(&nvmem_notifier, NVMEM_ADD, nvmem);
 868
 869         return nvmem;
 870
 871 err_remove_cells:
 872         nvmem_device_remove_all_cells(nvmem);
 873 err_teardown_compat:
 874         if (config->compat)
 875                 nvmem_sysfs_remove_compat(nvmem, config);
 876 err_device_del:
 877         device_del(&nvmem->dev);
 878 err_put_device:
 879         put_device(&nvmem->dev);
 880
 881         return ERR_PTR(rval);
 882 }
 883 EXPORT_SYMBOL_GPL(nvmem_register);
 884
 885 static void nvmem_device_release(struct kref *kref)
 886 {
 887         struct nvmem_device *nvmem;
 888
 889         nvmem = container_of(kref, struct nvmem_device, refcnt);
 890
 891         blocking_notifier_call_chain(&nvmem_notifier, NVMEM_REMOVE, nvmem);
 892
 893         if (nvmem->flags & FLAG_COMPAT)
 894                 device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom);
 895
 896         nvmem_device_remove_all_cells(nvmem);
 897         device_unregister(&nvmem->dev);
 898 }
 899
 900 /**
 901  * nvmem_unregister() - Unregister previously registered nvmem device
 902  *
 903  * @nvmem: Pointer to previously registered nvmem device.
 904  */
 905 void nvmem_unregister(struct nvmem_device *nvmem)
 906 {
 907         if (nvmem)
 908                 kref_put(&nvmem->refcnt, nvmem_device_release);
 909 }
 910 EXPORT_SYMBOL_GPL(nvmem_unregister);
 911
 912 static void devm_nvmem_unregister(void *nvmem)
 913 {
 914         nvmem_unregister(nvmem);
 915 }
 916
 917 /**
 918  * devm_nvmem_register() - Register a managed nvmem device for given
 919  * nvmem_config.
 920  * Also creates a binary entry in /sys/bus/nvmem/devices/dev-name/nvmem
 921  *
 922  * @dev: Device that uses the nvmem device.
 923  * @config: nvmem device configuration with which nvmem device is created.
 924  *
 925  * Return: Will be an ERR_PTR() on error or a valid pointer to nvmem_device
 926  * on success.
 927  */
 928 struct nvmem_device *devm_nvmem_register(struct device *dev,
 929                                          const struct nvmem_config *config)
 930 {
 931         struct nvmem_device *nvmem;
 932         int ret;
 933
 934         nvmem = nvmem_register(config);
 935         if (IS_ERR(nvmem))
 936                 return nvmem;
 937
 938         ret = devm_add_action_or_reset(dev, devm_nvmem_unregister, nvmem);
 939         if (ret)
 940                 return ERR_PTR(ret);
 941
 942         return nvmem;
 943 }
 944 EXPORT_SYMBOL_GPL(devm_nvmem_register);
 945
 946 static struct nvmem_device *__nvmem_device_get(void *data,
 947                         int (*match)(struct device *dev, const void *data))
 948 {
 949         struct nvmem_device *nvmem = NULL;
 950         struct device *dev;
 951
 952         mutex_lock(&nvmem_mutex);
 953         dev = bus_find_device(&nvmem_bus_type, NULL, data, match);
 954         if (dev)
 955                 nvmem = to_nvmem_device(dev);
 956         mutex_unlock(&nvmem_mutex);
 957         if (!nvmem)
 958                 return ERR_PTR(-EPROBE_DEFER);
 959
 960         if (!try_module_get(nvmem->owner)) {
 961                 dev_err(&nvmem->dev,
 962                         "could not increase module refcount for cell %s\n",
 963                         nvmem_dev_name(nvmem));
 964
 965                 put_device(&nvmem->dev);
 966                 return ERR_PTR(-EINVAL);
 967         }
 968
 969         kref_get(&nvmem->refcnt);
 970
 971         return nvmem;
 972 }
 973
 974 static void __nvmem_device_put(struct nvmem_device *nvmem)
 975 {
 976         put_device(&nvmem->dev);
 977         module_put(nvmem->owner);
 978         kref_put(&nvmem->refcnt, nvmem_device_release);
 979 }
 980
 981 #if IS_ENABLED(CONFIG_OF)
 982 /**
 983  * of_nvmem_device_get() - Get nvmem device from a given id
 984  *
 985  * @np: Device tree node that uses the nvmem device.
 986  * @id: nvmem name from nvmem-names property.
 987  *
 988  * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
 989  * on success.
 990  */
 991 struct nvmem_device *of_nvmem_device_get(struct device_node *np, const char *id)
 992 {
 993
 994         struct device_node *nvmem_np;
 995         struct nvmem_device *nvmem;
 996         int index = 0;
 997
 998         if (id)
 999                 index = of_property_match_string(np, "nvmem-names", id);
1000
1001         nvmem_np = of_parse_phandle(np, "nvmem", index);
1002         if (!nvmem_np)
1003                 return ERR_PTR(-ENOENT);
1004
1005         nvmem = __nvmem_device_get(nvmem_np, device_match_of_node);
1006         of_node_put(nvmem_np);
1007         return nvmem;
1008 }
1009 EXPORT_SYMBOL_GPL(of_nvmem_device_get);
1010 #endif
1011
1012 /**
1013  * nvmem_device_get() - Get nvmem device from a given id
1014  *
1015  * @dev: Device that uses the nvmem device.
1016  * @dev_name: name of the requested nvmem device.
1017  *
1018  * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
1019  * on success.
1020  */
1021 struct nvmem_device *nvmem_device_get(struct device *dev, const char *dev_name)
1022 {
1023         if (dev->of_node) { /* try dt first */
1024                 struct nvmem_device *nvmem;
1025
1026                 nvmem = of_nvmem_device_get(dev->of_node, dev_name);
1027
1028                 if (!IS_ERR(nvmem) || PTR_ERR(nvmem) == -EPROBE_DEFER)
1029                         return nvmem;
1030
1031         }
1032
1033         return __nvmem_device_get((void *)dev_name, device_match_name);
1034 }
1035 EXPORT_SYMBOL_GPL(nvmem_device_get);
1036
1037 /**
1038  * nvmem_device_find() - Find nvmem device with matching function
1039  *
1040  * @data: Data to pass to match function
1041  * @match: Callback function to check device
1042  *
1043  * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
1044  * on success.
1045  */
1046 struct nvmem_device *nvmem_device_find(void *data,
1047                         int (*match)(struct device *dev, const void *data))
1048 {
1049         return __nvmem_device_get(data, match);
1050 }
1051 EXPORT_SYMBOL_GPL(nvmem_device_find);
1052
1053 static int devm_nvmem_device_match(struct device *dev, void *res, void *data)
1054 {
1055         struct nvmem_device **nvmem = res;
1056
1057         if (WARN_ON(!nvmem || !*nvmem))
1058                 return 0;
1059
1060         return *nvmem == data;
1061 }
1062
1063 static void devm_nvmem_device_release(struct device *dev, void *res)
1064 {
1065         nvmem_device_put(*(struct nvmem_device **)res);
1066 }
1067
1068 /**
1069  * devm_nvmem_device_put() - put alredy got nvmem device
1070  *
1071  * @dev: Device that uses the nvmem device.
1072  * @nvmem: pointer to nvmem device allocated by devm_nvmem_cell_get(),
1073  * that needs to be released.
1074  */
1075 void devm_nvmem_device_put(struct device *dev, struct nvmem_device *nvmem)
1076 {
1077         int ret;
1078
1079         ret = devres_release(dev, devm_nvmem_device_release,
1080                              devm_nvmem_device_match, nvmem);
1081
1082         WARN_ON(ret);
1083 }
1084 EXPORT_SYMBOL_GPL(devm_nvmem_device_put);
1085
1086 /**
1087  * nvmem_device_put() - put alredy got nvmem device
1088  *
1089  * @nvmem: pointer to nvmem device that needs to be released.
1090  */
1091 void nvmem_device_put(struct nvmem_device *nvmem)
1092 {
1093         __nvmem_device_put(nvmem);
1094 }
1095 EXPORT_SYMBOL_GPL(nvmem_device_put);
1096
1097 /**
1098  * devm_nvmem_device_get() - Get nvmem cell of device form a given id
1099  *
1100  * @dev: Device that requests the nvmem device.
1101  * @id: name id for the requested nvmem device.
1102  *
1103  * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_cell
1104  * on success.  The nvmem_cell will be freed by the automatically once the
1105  * device is freed.
1106  */
1107 struct nvmem_device *devm_nvmem_device_get(struct device *dev, const char *id)
1108 {
1109         struct nvmem_device **ptr, *nvmem;
1110
1111         ptr = devres_alloc(devm_nvmem_device_release, sizeof(*ptr), GFP_KERNEL);
1112         if (!ptr)
1113                 return ERR_PTR(-ENOMEM);
1114
1115         nvmem = nvmem_device_get(dev, id);
1116         if (!IS_ERR(nvmem)) {
1117                 *ptr = nvmem;
1118                 devres_add(dev, ptr);
1119         } else {
1120                 devres_free(ptr);
1121         }
1122
1123         return nvmem;
1124 }
1125 EXPORT_SYMBOL_GPL(devm_nvmem_device_get);
1126
1127 static struct nvmem_cell *nvmem_create_cell(struct nvmem_cell_entry *entry, const char *id)
1128 {
1129         struct nvmem_cell *cell;
1130         const char *name = NULL;
1131
1132         cell = kzalloc(sizeof(*cell), GFP_KERNEL);
1133         if (!cell)
1134                 return ERR_PTR(-ENOMEM);
1135
1136         if (id) {
1137                 name = kstrdup_const(id, GFP_KERNEL);
1138                 if (!name) {
1139                         kfree(cell);
1140                         return ERR_PTR(-ENOMEM);
1141                 }
1142         }
1143
1144         cell->id = name;
1145         cell->entry = entry;
1146
1147         return cell;
1148 }
1149
1150 static struct nvmem_cell *
1151 nvmem_cell_get_from_lookup(struct device *dev, const char *con_id)
1152 {
1153         struct nvmem_cell_entry *cell_entry;
1154         struct nvmem_cell *cell = ERR_PTR(-ENOENT);
1155         struct nvmem_cell_lookup *lookup;
1156         struct nvmem_device *nvmem;
1157         const char *dev_id;
1158
1159         if (!dev)
1160                 return ERR_PTR(-EINVAL);
1161
1162         dev_id = dev_name(dev);
1163
1164         mutex_lock(&nvmem_lookup_mutex);
1165
1166         list_for_each_entry(lookup, &nvmem_lookup_list, node) {
1167                 if ((strcmp(lookup->dev_id, dev_id) == 0) &&
1168                     (strcmp(lookup->con_id, con_id) == 0)) {
1169                         /* This is the right entry. */
1170                         nvmem = __nvmem_device_get((void *)lookup->nvmem_name,
1171                                                    device_match_name);
1172                         if (IS_ERR(nvmem)) {
1173                                 /* Provider may not be registered yet. */
1174                                 cell = ERR_CAST(nvmem);
1175                                 break;
1176                         }
1177
1178                         cell_entry = nvmem_find_cell_entry_by_name(nvmem,
1179                                                                    lookup->cell_name);
1180                         if (!cell_entry) {
1181                                 __nvmem_device_put(nvmem);
1182                                 cell = ERR_PTR(-ENOENT);
1183                         } else {
1184                                 cell = nvmem_create_cell(cell_entry, con_id);
1185                                 if (IS_ERR(cell))
1186                                         __nvmem_device_put(nvmem);
1187                         }
1188                         break;
1189                 }
1190         }
1191
1192         mutex_unlock(&nvmem_lookup_mutex);
1193         return cell;
1194 }
1195
1196 #if IS_ENABLED(CONFIG_OF)
1197 static struct nvmem_cell_entry *
1198 nvmem_find_cell_entry_by_node(struct nvmem_device *nvmem, struct device_node *np)
1199 {
1200         struct nvmem_cell_entry *iter, *cell = NULL;
1201
1202         mutex_lock(&nvmem_mutex);
1203         list_for_each_entry(iter, &nvmem->cells, node) {
1204                 if (np == iter->np) {
1205                         cell = iter;
1206                         break;
1207                 }
1208         }
1209         mutex_unlock(&nvmem_mutex);
1210
1211         return cell;
1212 }
1213
1214 /**
1215  * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
1216  *
1217  * @np: Device tree node that uses the nvmem cell.
1218  * @id: nvmem cell name from nvmem-cell-names property, or NULL
1219  *      for the cell at index 0 (the lone cell with no accompanying
1220  *      nvmem-cell-names property).
1221  *
1222  * Return: Will be an ERR_PTR() on error or a valid pointer
1223  * to a struct nvmem_cell.  The nvmem_cell will be freed by the
1224  * nvmem_cell_put().
1225  */
1226 struct nvmem_cell *of_nvmem_cell_get(struct device_node *np, const char *id)
1227 {
1228         struct device_node *cell_np, *nvmem_np;
1229         struct nvmem_device *nvmem;
1230         struct nvmem_cell_entry *cell_entry;
1231         struct nvmem_cell *cell;
1232         int index = 0;
1233
1234         /* if cell name exists, find index to the name */
1235         if (id)
1236                 index = of_property_match_string(np, "nvmem-cell-names", id);
1237
1238         cell_np = of_parse_phandle(np, "nvmem-cells", index);
1239         if (!cell_np)
1240                 return ERR_PTR(-ENOENT);
1241
1242         nvmem_np = of_get_next_parent(cell_np);
1243         if (!nvmem_np)
1244                 return ERR_PTR(-EINVAL);
1245
1246         nvmem = __nvmem_device_get(nvmem_np, device_match_of_node);
1247         of_node_put(nvmem_np);
1248         if (IS_ERR(nvmem))
1249                 return ERR_CAST(nvmem);
1250
1251         cell_entry = nvmem_find_cell_entry_by_node(nvmem, cell_np);
1252         if (!cell_entry) {
1253                 __nvmem_device_put(nvmem);
1254                 return ERR_PTR(-ENOENT);
1255         }
1256
1257         cell = nvmem_create_cell(cell_entry, id);
1258         if (IS_ERR(cell))
1259                 __nvmem_device_put(nvmem);
1260
1261         return cell;
1262 }
1263 EXPORT_SYMBOL_GPL(of_nvmem_cell_get);
1264 #endif
1265
1266 /**
1267  * nvmem_cell_get() - Get nvmem cell of device form a given cell name
1268  *
1269  * @dev: Device that requests the nvmem cell.
1270  * @id: nvmem cell name to get (this corresponds with the name from the
1271  *      nvmem-cell-names property for DT systems and with the con_id from
1272  *      the lookup entry for non-DT systems).
1273  *
1274  * Return: Will be an ERR_PTR() on error or a valid pointer
1275  * to a struct nvmem_cell.  The nvmem_cell will be freed by the
1276  * nvmem_cell_put().
1277  */
1278 struct nvmem_cell *nvmem_cell_get(struct device *dev, const char *id)
1279 {
1280         struct nvmem_cell *cell;
1281
1282         if (dev->of_node) { /* try dt first */
1283                 cell = of_nvmem_cell_get(dev->of_node, id);
1284                 if (!IS_ERR(cell) || PTR_ERR(cell) == -EPROBE_DEFER)
1285                         return cell;
1286         }
1287
1288         /* NULL cell id only allowed for device tree; invalid otherwise */
1289         if (!id)
1290                 return ERR_PTR(-EINVAL);
1291
1292         return nvmem_cell_get_from_lookup(dev, id);
1293 }
1294 EXPORT_SYMBOL_GPL(nvmem_cell_get);
1295
1296 static void devm_nvmem_cell_release(struct device *dev, void *res)
1297 {
1298         nvmem_cell_put(*(struct nvmem_cell **)res);
1299 }
1300
1301 /**
1302  * devm_nvmem_cell_get() - Get nvmem cell of device form a given id
1303  *
1304  * @dev: Device that requests the nvmem cell.
1305  * @id: nvmem cell name id to get.
1306  *
1307  * Return: Will be an ERR_PTR() on error or a valid pointer
1308  * to a struct nvmem_cell.  The nvmem_cell will be freed by the
1309  * automatically once the device is freed.
1310  */
1311 struct nvmem_cell *devm_nvmem_cell_get(struct device *dev, const char *id)
1312 {
1313         struct nvmem_cell **ptr, *cell;
1314
1315         ptr = devres_alloc(devm_nvmem_cell_release, sizeof(*ptr), GFP_KERNEL);
1316         if (!ptr)
1317                 return ERR_PTR(-ENOMEM);
1318
1319         cell = nvmem_cell_get(dev, id);
1320         if (!IS_ERR(cell)) {
1321                 *ptr = cell;
1322                 devres_add(dev, ptr);
1323         } else {
1324                 devres_free(ptr);
1325         }
1326
1327         return cell;
1328 }
1329 EXPORT_SYMBOL_GPL(devm_nvmem_cell_get);
1330
1331 static int devm_nvmem_cell_match(struct device *dev, void *res, void *data)
1332 {
1333         struct nvmem_cell **c = res;
1334
1335         if (WARN_ON(!c || !*c))
1336                 return 0;
1337
1338         return *c == data;
1339 }
1340
1341 /**
1342  * devm_nvmem_cell_put() - Release previously allocated nvmem cell
1343  * from devm_nvmem_cell_get.
1344  *
1345  * @dev: Device that requests the nvmem cell.
1346  * @cell: Previously allocated nvmem cell by devm_nvmem_cell_get().
1347  */
1348 void devm_nvmem_cell_put(struct device *dev, struct nvmem_cell *cell)
1349 {
1350         int ret;
1351
1352         ret = devres_release(dev, devm_nvmem_cell_release,
1353                                 devm_nvmem_cell_match, cell);
1354
1355         WARN_ON(ret);
1356 }
1357 EXPORT_SYMBOL(devm_nvmem_cell_put);
1358
1359 /**
1360  * nvmem_cell_put() - Release previously allocated nvmem cell.
1361  *
1362  * @cell: Previously allocated nvmem cell by nvmem_cell_get().
1363  */
1364 void nvmem_cell_put(struct nvmem_cell *cell)
1365 {
1366         struct nvmem_device *nvmem = cell->entry->nvmem;
1367
1368         if (cell->id)
1369                 kfree_const(cell->id);
1370
1371         kfree(cell);
1372         __nvmem_device_put(nvmem);
1373 }
1374 EXPORT_SYMBOL_GPL(nvmem_cell_put);
1375
1376 static void nvmem_shift_read_buffer_in_place(struct nvmem_cell_entry *cell, void *buf)
1377 {
1378         u8 *p, *b;
1379         int i, extra, bit_offset = cell->bit_offset;
1380
1381         p = b = buf;
1382         if (bit_offset) {
1383                 /* First shift */
1384                 *b++ >>= bit_offset;
1385
1386                 /* setup rest of the bytes if any */
1387                 for (i = 1; i < cell->bytes; i++) {
1388                         /* Get bits from next byte and shift them towards msb */
1389                         *p |= *b << (BITS_PER_BYTE - bit_offset);
1390
1391                         p = b;
1392                         *b++ >>= bit_offset;
1393                 }
1394         } else {
1395                 /* point to the msb */
1396                 p += cell->bytes - 1;
1397         }
1398
1399         /* result fits in less bytes */
1400         extra = cell->bytes - DIV_ROUND_UP(cell->nbits, BITS_PER_BYTE);
1401         while (--extra >= 0)
1402                 *p-- = 0;
1403
1404         /* clear msb bits if any leftover in the last byte */
1405         if (cell->nbits % BITS_PER_BYTE)
1406                 *p &= GENMASK((cell->nbits % BITS_PER_BYTE) - 1, 0);
1407 }
1408
1409 static int __nvmem_cell_read(struct nvmem_device *nvmem,
1410                       struct nvmem_cell_entry *cell,
1411                       void *buf, size_t *len, const char *id)
1412 {
1413         int rc;
1414
1415         rc = nvmem_reg_read(nvmem, cell->offset, buf, cell->bytes);
1416
1417         if (rc)
1418                 return rc;
1419
1420         /* shift bits in-place */
1421         if (cell->bit_offset || cell->nbits)
1422                 nvmem_shift_read_buffer_in_place(cell, buf);
1423
1424         if (nvmem->cell_post_process) {
1425                 rc = nvmem->cell_post_process(nvmem->priv, id,
1426                                               cell->offset, buf, cell->bytes);
1427                 if (rc)
1428                         return rc;
1429         }
1430
1431         if (len)
1432                 *len = cell->bytes;
1433
1434         return 0;
1435 }
1436
1437 /**
1438  * nvmem_cell_read() - Read a given nvmem cell
1439  *
1440  * @cell: nvmem cell to be read.
1441  * @len: pointer to length of cell which will be populated on successful read;
1442  *       can be NULL.
1443  *
1444  * Return: ERR_PTR() on error or a valid pointer to a buffer on success. The
1445  * buffer should be freed by the consumer with a kfree().
1446  */
1447 void *nvmem_cell_read(struct nvmem_cell *cell, size_t *len)
1448 {
1449         struct nvmem_device *nvmem = cell->entry->nvmem;
1450         u8 *buf;
1451         int rc;
1452
1453         if (!nvmem)
1454                 return ERR_PTR(-EINVAL);
1455
1456         buf = kzalloc(cell->entry->bytes, GFP_KERNEL);
1457         if (!buf)
1458                 return ERR_PTR(-ENOMEM);
1459
1460         rc = __nvmem_cell_read(nvmem, cell->entry, buf, len, cell->id);
1461         if (rc) {
1462                 kfree(buf);
1463                 return ERR_PTR(rc);
1464         }
1465
1466         return buf;
1467 }
1468 EXPORT_SYMBOL_GPL(nvmem_cell_read);
1469
1470 static void *nvmem_cell_prepare_write_buffer(struct nvmem_cell_entry *cell,
1471                                              u8 *_buf, int len)
1472 {
1473         struct nvmem_device *nvmem = cell->nvmem;
1474         int i, rc, nbits, bit_offset = cell->bit_offset;
1475         u8 v, *p, *buf, *b, pbyte, pbits;
1476
1477         nbits = cell->nbits;
1478         buf = kzalloc(cell->bytes, GFP_KERNEL);
1479         if (!buf)
1480                 return ERR_PTR(-ENOMEM);
1481
1482         memcpy(buf, _buf, len);
1483         p = b = buf;
1484
1485         if (bit_offset) {
1486                 pbyte = *b;
1487                 *b <<= bit_offset;
1488
1489                 /* setup the first byte with lsb bits from nvmem */
1490                 rc = nvmem_reg_read(nvmem, cell->offset, &v, 1);
1491                 if (rc)
1492                         goto err;
1493                 *b++ |= GENMASK(bit_offset - 1, 0) & v;
1494
1495                 /* setup rest of the byte if any */
1496                 for (i = 1; i < cell->bytes; i++) {
1497                         /* Get last byte bits and shift them towards lsb */
1498                         pbits = pbyte >> (BITS_PER_BYTE - 1 - bit_offset);
1499                         pbyte = *b;
1500                         p = b;
1501                         *b <<= bit_offset;
1502                         *b++ |= pbits;
1503                 }
1504         }
1505
1506         /* if it's not end on byte boundary */
1507         if ((nbits + bit_offset) % BITS_PER_BYTE) {
1508                 /* setup the last byte with msb bits from nvmem */
1509                 rc = nvmem_reg_read(nvmem,
1510                                     cell->offset + cell->bytes - 1, &v, 1);
1511                 if (rc)
1512                         goto err;
1513                 *p |= GENMASK(7, (nbits + bit_offset) % BITS_PER_BYTE) & v;
1514
1515         }
1516
1517         return buf;
1518 err:
1519         kfree(buf);
1520         return ERR_PTR(rc);
1521 }
1522
1523 static int __nvmem_cell_entry_write(struct nvmem_cell_entry *cell, void *buf, size_t len)
1524 {
1525         struct nvmem_device *nvmem = cell->nvmem;
1526         int rc;
1527
1528         if (!nvmem || nvmem->read_only ||
1529             (cell->bit_offset == 0 && len != cell->bytes))
1530                 return -EINVAL;
1531
1532         if (cell->bit_offset || cell->nbits) {
1533                 buf = nvmem_cell_prepare_write_buffer(cell, buf, len);
1534                 if (IS_ERR(buf))
1535                         return PTR_ERR(buf);
1536         }
1537
1538         rc = nvmem_reg_write(nvmem, cell->offset, buf, cell->bytes);
1539
1540         /* free the tmp buffer */
1541         if (cell->bit_offset || cell->nbits)
1542                 kfree(buf);
1543
1544         if (rc)
1545                 return rc;
1546
1547         return len;
1548 }
1549
1550 /**
1551  * nvmem_cell_write() - Write to a given nvmem cell
1552  *
1553  * @cell: nvmem cell to be written.
1554  * @buf: Buffer to be written.
1555  * @len: length of buffer to be written to nvmem cell.
1556  *
1557  * Return: length of bytes written or negative on failure.
1558  */
1559 int nvmem_cell_write(struct nvmem_cell *cell, void *buf, size_t len)
1560 {
1561         return __nvmem_cell_entry_write(cell->entry, buf, len);
1562 }
1563
1564 EXPORT_SYMBOL_GPL(nvmem_cell_write);
1565
1566 static int nvmem_cell_read_common(struct device *dev, const char *cell_id,
1567                                   void *val, size_t count)
1568 {
1569         struct nvmem_cell *cell;
1570         void *buf;
1571         size_t len;
1572
1573         cell = nvmem_cell_get(dev, cell_id);
1574         if (IS_ERR(cell))
1575                 return PTR_ERR(cell);
1576
1577         buf = nvmem_cell_read(cell, &len);
1578         if (IS_ERR(buf)) {
1579                 nvmem_cell_put(cell);
1580                 return PTR_ERR(buf);
1581         }
1582         if (len != count) {
1583                 kfree(buf);
1584                 nvmem_cell_put(cell);
1585                 return -EINVAL;
1586         }
1587         memcpy(val, buf, count);
1588         kfree(buf);
1589         nvmem_cell_put(cell);
1590
1591         return 0;
1592 }
1593
1594 /**
1595  * nvmem_cell_read_u8() - Read a cell value as a u8
1596  *
1597  * @dev: Device that requests the nvmem cell.
1598  * @cell_id: Name of nvmem cell to read.
1599  * @val: pointer to output value.
1600  *
1601  * Return: 0 on success or negative errno.
1602  */
1603 int nvmem_cell_read_u8(struct device *dev, const char *cell_id, u8 *val)
1604 {
1605         return nvmem_cell_read_common(dev, cell_id, val, sizeof(*val));
1606 }
1607 EXPORT_SYMBOL_GPL(nvmem_cell_read_u8);
1608
1609 /**
1610  * nvmem_cell_read_u16() - Read a cell value as a u16
1611  *
1612  * @dev: Device that requests the nvmem cell.
1613  * @cell_id: Name of nvmem cell to read.
1614  * @val: pointer to output value.
1615  *
1616  * Return: 0 on success or negative errno.
1617  */
1618 int nvmem_cell_read_u16(struct device *dev, const char *cell_id, u16 *val)
1619 {
1620         return nvmem_cell_read_common(dev, cell_id, val, sizeof(*val));
1621 }
1622 EXPORT_SYMBOL_GPL(nvmem_cell_read_u16);
1623
1624 /**
1625  * nvmem_cell_read_u32() - Read a cell value as a u32
1626  *
1627  * @dev: Device that requests the nvmem cell.
1628  * @cell_id: Name of nvmem cell to read.
1629  * @val: pointer to output value.
1630  *
1631  * Return: 0 on success or negative errno.
1632  */
1633 int nvmem_cell_read_u32(struct device *dev, const char *cell_id, u32 *val)
1634 {
1635         return nvmem_cell_read_common(dev, cell_id, val, sizeof(*val));
1636 }
1637 EXPORT_SYMBOL_GPL(nvmem_cell_read_u32);
1638
1639 /**
1640  * nvmem_cell_read_u64() - Read a cell value as a u64
1641  *
1642  * @dev: Device that requests the nvmem cell.
1643  * @cell_id: Name of nvmem cell to read.
1644  * @val: pointer to output value.
1645  *
1646  * Return: 0 on success or negative errno.
1647  */
1648 int nvmem_cell_read_u64(struct device *dev, const char *cell_id, u64 *val)
1649 {
1650         return nvmem_cell_read_common(dev, cell_id, val, sizeof(*val));
1651 }
1652 EXPORT_SYMBOL_GPL(nvmem_cell_read_u64);
1653
1654 static const void *nvmem_cell_read_variable_common(struct device *dev,
1655                                                    const char *cell_id,
1656                                                    size_t max_len, size_t *len)
1657 {
1658         struct nvmem_cell *cell;
1659         int nbits;
1660         void *buf;
1661
1662         cell = nvmem_cell_get(dev, cell_id);
1663         if (IS_ERR(cell))
1664                 return cell;
1665
1666         nbits = cell->entry->nbits;
1667         buf = nvmem_cell_read(cell, len);
1668         nvmem_cell_put(cell);
1669         if (IS_ERR(buf))
1670                 return buf;
1671
1672         /*
1673          * If nbits is set then nvmem_cell_read() can significantly exaggerate
1674          * the length of the real data. Throw away the extra junk.
1675          */
1676         if (nbits)
1677                 *len = DIV_ROUND_UP(nbits, 8);
1678
1679         if (*len > max_len) {
1680                 kfree(buf);
1681                 return ERR_PTR(-ERANGE);
1682         }
1683
1684         return buf;
1685 }
1686
1687 /**
1688  * nvmem_cell_read_variable_le_u32() - Read up to 32-bits of data as a little endian number.
1689  *
1690  * @dev: Device that requests the nvmem cell.
1691  * @cell_id: Name of nvmem cell to read.
1692  * @val: pointer to output value.
1693  *
1694  * Return: 0 on success or negative errno.
1695  */
1696 int nvmem_cell_read_variable_le_u32(struct device *dev, const char *cell_id,
1697                                     u32 *val)
1698 {
1699         size_t len;
1700         const u8 *buf;
1701         int i;
1702
1703         buf = nvmem_cell_read_variable_common(dev, cell_id, sizeof(*val), &len);
1704         if (IS_ERR(buf))
1705                 return PTR_ERR(buf);
1706
1707         /* Copy w/ implicit endian conversion */
1708         *val = 0;
1709         for (i = 0; i < len; i++)
1710                 *val |= buf[i] << (8 * i);
1711
1712         kfree(buf);
1713
1714         return 0;
1715 }
1716 EXPORT_SYMBOL_GPL(nvmem_cell_read_variable_le_u32);
1717
1718 /**
1719  * nvmem_cell_read_variable_le_u64() - Read up to 64-bits of data as a little endian number.
1720  *
1721  * @dev: Device that requests the nvmem cell.
1722  * @cell_id: Name of nvmem cell to read.
1723  * @val: pointer to output value.
1724  *
1725  * Return: 0 on success or negative errno.
1726  */
1727 int nvmem_cell_read_variable_le_u64(struct device *dev, const char *cell_id,
1728                                     u64 *val)
1729 {
1730         size_t len;
1731         const u8 *buf;
1732         int i;
1733
1734         buf = nvmem_cell_read_variable_common(dev, cell_id, sizeof(*val), &len);
1735         if (IS_ERR(buf))
1736                 return PTR_ERR(buf);
1737
1738         /* Copy w/ implicit endian conversion */
1739         *val = 0;
1740         for (i = 0; i < len; i++)
1741                 *val |= (uint64_t)buf[i] << (8 * i);
1742
1743         kfree(buf);
1744
1745         return 0;
1746 }
1747 EXPORT_SYMBOL_GPL(nvmem_cell_read_variable_le_u64);
1748
1749 /**
1750  * nvmem_device_cell_read() - Read a given nvmem device and cell
1751  *
1752  * @nvmem: nvmem device to read from.
1753  * @info: nvmem cell info to be read.
1754  * @buf: buffer pointer which will be populated on successful read.
1755  *
1756  * Return: length of successful bytes read on success and negative
1757  * error code on error.
1758  */
1759 ssize_t nvmem_device_cell_read(struct nvmem_device *nvmem,
1760                            struct nvmem_cell_info *info, void *buf)
1761 {
1762         struct nvmem_cell_entry cell;
1763         int rc;
1764         ssize_t len;
1765
1766         if (!nvmem)
1767                 return -EINVAL;
1768
1769         rc = nvmem_cell_info_to_nvmem_cell_entry_nodup(nvmem, info, &cell);
1770         if (rc)
1771                 return rc;
1772
1773         rc = __nvmem_cell_read(nvmem, &cell, buf, &len, NULL);
1774         if (rc)
1775                 return rc;
1776
1777         return len;
1778 }
1779 EXPORT_SYMBOL_GPL(nvmem_device_cell_read);
1780
1781 /**
1782  * nvmem_device_cell_write() - Write cell to a given nvmem device
1783  *
1784  * @nvmem: nvmem device to be written to.
1785  * @info: nvmem cell info to be written.
1786  * @buf: buffer to be written to cell.
1787  *
1788  * Return: length of bytes written or negative error code on failure.
1789  */
1790 int nvmem_device_cell_write(struct nvmem_device *nvmem,
1791                             struct nvmem_cell_info *info, void *buf)
1792 {
1793         struct nvmem_cell_entry cell;
1794         int rc;
1795
1796         if (!nvmem)
1797                 return -EINVAL;
1798
1799         rc = nvmem_cell_info_to_nvmem_cell_entry_nodup(nvmem, info, &cell);
1800         if (rc)
1801                 return rc;
1802
1803         return __nvmem_cell_entry_write(&cell, buf, cell.bytes);
1804 }
1805 EXPORT_SYMBOL_GPL(nvmem_device_cell_write);
1806
1807 /**
1808  * nvmem_device_read() - Read from a given nvmem device
1809  *
1810  * @nvmem: nvmem device to read from.
1811  * @offset: offset in nvmem device.
1812  * @bytes: number of bytes to read.
1813  * @buf: buffer pointer which will be populated on successful read.
1814  *
1815  * Return: length of successful bytes read on success and negative
1816  * error code on error.
1817  */
1818 int nvmem_device_read(struct nvmem_device *nvmem,
1819                       unsigned int offset,
1820                       size_t bytes, void *buf)
1821 {
1822         int rc;
1823
1824         if (!nvmem)
1825                 return -EINVAL;
1826
1827         rc = nvmem_reg_read(nvmem, offset, buf, bytes);
1828
1829         if (rc)
1830                 return rc;
1831
1832         return bytes;
1833 }
1834 EXPORT_SYMBOL_GPL(nvmem_device_read);
1835
1836 /**
1837  * nvmem_device_write() - Write cell to a given nvmem device
1838  *
1839  * @nvmem: nvmem device to be written to.
1840  * @offset: offset in nvmem device.
1841  * @bytes: number of bytes to write.
1842  * @buf: buffer to be written.
1843  *
1844  * Return: length of bytes written or negative error code on failure.
1845  */
1846 int nvmem_device_write(struct nvmem_device *nvmem,
1847                        unsigned int offset,
1848                        size_t bytes, void *buf)
1849 {
1850         int rc;
1851
1852         if (!nvmem)
1853                 return -EINVAL;
1854
1855         rc = nvmem_reg_write(nvmem, offset, buf, bytes);
1856
1857         if (rc)
1858                 return rc;
1859
1860
1861         return bytes;
1862 }
1863 EXPORT_SYMBOL_GPL(nvmem_device_write);
1864
1865 /**
1866  * nvmem_add_cell_table() - register a table of cell info entries
1867  *
1868  * @table: table of cell info entries
1869  */
1870 void nvmem_add_cell_table(struct nvmem_cell_table *table)
1871 {
1872         mutex_lock(&nvmem_cell_mutex);
1873         list_add_tail(&table->node, &nvmem_cell_tables);
1874         mutex_unlock(&nvmem_cell_mutex);
1875 }
1876 EXPORT_SYMBOL_GPL(nvmem_add_cell_table);
1877
1878 /**
1879  * nvmem_del_cell_table() - remove a previously registered cell info table
1880  *
1881  * @table: table of cell info entries
1882  */
1883 void nvmem_del_cell_table(struct nvmem_cell_table *table)
1884 {
1885         mutex_lock(&nvmem_cell_mutex);
1886         list_del(&table->node);
1887         mutex_unlock(&nvmem_cell_mutex);
1888 }
1889 EXPORT_SYMBOL_GPL(nvmem_del_cell_table);
1890
1891 /**
1892  * nvmem_add_cell_lookups() - register a list of cell lookup entries
1893  *
1894  * @entries: array of cell lookup entries
1895  * @nentries: number of cell lookup entries in the array
1896  */
1897 void nvmem_add_cell_lookups(struct nvmem_cell_lookup *entries, size_t nentries)
1898 {
1899         int i;
1900
1901         mutex_lock(&nvmem_lookup_mutex);
1902         for (i = 0; i < nentries; i++)
1903                 list_add_tail(&entries[i].node, &nvmem_lookup_list);
1904         mutex_unlock(&nvmem_lookup_mutex);
1905 }
1906 EXPORT_SYMBOL_GPL(nvmem_add_cell_lookups);
1907
1908 /**
1909  * nvmem_del_cell_lookups() - remove a list of previously added cell lookup
1910  *                            entries
1911  *
1912  * @entries: array of cell lookup entries
1913  * @nentries: number of cell lookup entries in the array
1914  */
1915 void nvmem_del_cell_lookups(struct nvmem_cell_lookup *entries, size_t nentries)
1916 {
1917         int i;
1918
1919         mutex_lock(&nvmem_lookup_mutex);
1920         for (i = 0; i < nentries; i++)
1921                 list_del(&entries[i].node);
1922         mutex_unlock(&nvmem_lookup_mutex);
1923 }
1924 EXPORT_SYMBOL_GPL(nvmem_del_cell_lookups);
1925
1926 /**
1927  * nvmem_dev_name() - Get the name of a given nvmem device.
1928  *
1929  * @nvmem: nvmem device.
1930  *
1931  * Return: name of the nvmem device.
1932  */
1933 const char *nvmem_dev_name(struct nvmem_device *nvmem)
1934 {
1935         return dev_name(&nvmem->dev);
1936 }
1937 EXPORT_SYMBOL_GPL(nvmem_dev_name);
1938
1939 static int __init nvmem_init(void)
1940 {
1941         return bus_register(&nvmem_bus_type);
1942 }
1943
1944 static void __exit nvmem_exit(void)
1945 {
1946         bus_unregister(&nvmem_bus_type);
1947 }
1948
1949 subsys_initcall(nvmem_init);
1950 module_exit(nvmem_exit);
1951
1952 MODULE_AUTHOR("Srinivas Kandagatla <srinivas.kandagatla@linaro.org");
1953 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com");
1954 MODULE_DESCRIPTION("nvmem Driver Core");
1955 MODULE_LICENSE("GPL v2");