drivers/base/regmap/regcache.c

   1 /*
   2  * Register cache access API
   3  *
   4  * Copyright 2011 Wolfson Microelectronics plc
   5  *
   6  * Author: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/bsearch.h>
  14 #include <linux/device.h>
  15 #include <linux/export.h>
  16 #include <linux/slab.h>
  17 #include <linux/sort.h>
  18
  19 #include "trace.h"
  20 #include "internal.h"
  21
  22 static const struct regcache_ops *cache_types[] = {
  23         &regcache_rbtree_ops,
  24         &regcache_lzo_ops,
  25         &regcache_flat_ops,
  26 };
  27
  28 static int regcache_hw_init(struct regmap *map)
  29 {
  30         int i, j;
  31         int ret;
  32         int count;
  33         unsigned int val;
  34         void *tmp_buf;
  35
  36         if (!map->num_reg_defaults_raw)
  37                 return -EINVAL;
  38
  39         /* calculate the size of reg_defaults */
  40         for (count = 0, i = 0; i < map->num_reg_defaults_raw; i++)
  41                 if (!regmap_volatile(map, i * map->reg_stride))
  42                         count++;
  43
  44         /* all registers are volatile, so just bypass */
  45         if (!count) {
  46                 map->cache_bypass = true;
  47                 return 0;
  48         }
  49
  50         map->num_reg_defaults = count;
  51         map->reg_defaults = kmalloc_array(count, sizeof(struct reg_default),
  52                                           GFP_KERNEL);
  53         if (!map->reg_defaults)
  54                 return -ENOMEM;
  55
  56         if (!map->reg_defaults_raw) {
  57                 bool cache_bypass = map->cache_bypass;
  58                 dev_warn(map->dev, "No cache defaults, reading back from HW\n");
  59
  60                 /* Bypass the cache access till data read from HW*/
  61                 map->cache_bypass = true;
  62                 tmp_buf = kmalloc(map->cache_size_raw, GFP_KERNEL);
  63                 if (!tmp_buf) {
  64                         ret = -ENOMEM;
  65                         goto err_free;
  66                 }
  67                 ret = regmap_raw_read(map, 0, tmp_buf,
  68                                       map->num_reg_defaults_raw);
  69                 map->cache_bypass = cache_bypass;
  70                 if (ret < 0)
  71                         goto err_cache_free;
  72
  73                 map->reg_defaults_raw = tmp_buf;
  74                 map->cache_free = 1;
  75         }
  76
  77         /* fill the reg_defaults */
  78         for (i = 0, j = 0; i < map->num_reg_defaults_raw; i++) {
  79                 if (regmap_volatile(map, i * map->reg_stride))
  80                         continue;
  81                 val = regcache_get_val(map, map->reg_defaults_raw, i);
  82                 map->reg_defaults[j].reg = i * map->reg_stride;
  83                 map->reg_defaults[j].def = val;
  84                 j++;
  85         }
  86
  87         return 0;
  88
  89 err_cache_free:
  90         kfree(tmp_buf);
  91 err_free:
  92         kfree(map->reg_defaults);
  93
  94         return ret;
  95 }
  96
  97 int regcache_init(struct regmap *map, const struct regmap_config *config)
  98 {
  99         int ret;
 100         int i;
 101         void *tmp_buf;
 102
 103         for (i = 0; i < config->num_reg_defaults; i++)
 104                 if (config->reg_defaults[i].reg % map->reg_stride)
 105                         return -EINVAL;
 106
 107         if (map->cache_type == REGCACHE_NONE) {
 108                 map->cache_bypass = true;
 109                 return 0;
 110         }
 111
 112         for (i = 0; i < ARRAY_SIZE(cache_types); i++)
 113                 if (cache_types[i]->type == map->cache_type)
 114                         break;
 115
 116         if (i == ARRAY_SIZE(cache_types)) {
 117                 dev_err(map->dev, "Could not match compress type: %d\n",
 118                         map->cache_type);
 119                 return -EINVAL;
 120         }
 121
 122         map->num_reg_defaults = config->num_reg_defaults;
 123         map->num_reg_defaults_raw = config->num_reg_defaults_raw;
 124         map->reg_defaults_raw = config->reg_defaults_raw;
 125         map->cache_word_size = DIV_ROUND_UP(config->val_bits, 8);
 126         map->cache_size_raw = map->cache_word_size * config->num_reg_defaults_raw;
 127
 128         map->cache = NULL;
 129         map->cache_ops = cache_types[i];
 130
 131         if (!map->cache_ops->read ||
 132             !map->cache_ops->write ||
 133             !map->cache_ops->name)
 134                 return -EINVAL;
 135
 136         /* We still need to ensure that the reg_defaults
 137          * won't vanish from under us.  We'll need to make
 138          * a copy of it.
 139          */
 140         if (config->reg_defaults) {
 141                 if (!map->num_reg_defaults)
 142                         return -EINVAL;
 143                 tmp_buf = kmemdup(config->reg_defaults, map->num_reg_defaults *
 144                                   sizeof(struct reg_default), GFP_KERNEL);
 145                 if (!tmp_buf)
 146                         return -ENOMEM;
 147                 map->reg_defaults = tmp_buf;
 148         } else if (map->num_reg_defaults_raw) {
 149                 /* Some devices such as PMICs don't have cache defaults,
 150                  * we cope with this by reading back the HW registers and
 151                  * crafting the cache defaults by hand.
 152                  */
 153                 ret = regcache_hw_init(map);
 154                 if (ret < 0)
 155                         return ret;
 156                 if (map->cache_bypass)
 157                         return 0;
 158         }
 159
 160         if (!map->max_register)
 161                 map->max_register = map->num_reg_defaults_raw;
 162
 163         if (map->cache_ops->init) {
 164                 dev_dbg(map->dev, "Initializing %s cache\n",
 165                         map->cache_ops->name);
 166                 ret = map->cache_ops->init(map);
 167                 if (ret)
 168                         goto err_free;
 169         }
 170         return 0;
 171
 172 err_free:
 173         kfree(map->reg_defaults);
 174         if (map->cache_free)
 175                 kfree(map->reg_defaults_raw);
 176
 177         return ret;
 178 }
 179
 180 void regcache_exit(struct regmap *map)
 181 {
 182         if (map->cache_type == REGCACHE_NONE)
 183                 return;
 184
 185         BUG_ON(!map->cache_ops);
 186
 187         kfree(map->reg_defaults);
 188         if (map->cache_free)
 189                 kfree(map->reg_defaults_raw);
 190
 191         if (map->cache_ops->exit) {
 192                 dev_dbg(map->dev, "Destroying %s cache\n",
 193                         map->cache_ops->name);
 194                 map->cache_ops->exit(map);
 195         }
 196 }
 197
 198 /**
 199  * regcache_read: Fetch the value of a given register from the cache.
 200  *
 201  * @map: map to configure.
 202  * @reg: The register index.
 203  * @value: The value to be returned.
 204  *
 205  * Return a negative value on failure, 0 on success.
 206  */
 207 int regcache_read(struct regmap *map,
 208                   unsigned int reg, unsigned int *value)
 209 {
 210         int ret;
 211
 212         if (map->cache_type == REGCACHE_NONE)
 213                 return -ENOSYS;
 214
 215         BUG_ON(!map->cache_ops);
 216
 217         if (!regmap_volatile(map, reg)) {
 218                 ret = map->cache_ops->read(map, reg, value);
 219
 220                 if (ret == 0)
 221                         trace_regmap_reg_read_cache(map, reg, *value);
 222
 223                 return ret;
 224         }
 225
 226         return -EINVAL;
 227 }
 228
 229 /**
 230  * regcache_write: Set the value of a given register in the cache.
 231  *
 232  * @map: map to configure.
 233  * @reg: The register index.
 234  * @value: The new register value.
 235  *
 236  * Return a negative value on failure, 0 on success.
 237  */
 238 int regcache_write(struct regmap *map,
 239                    unsigned int reg, unsigned int value)
 240 {
 241         if (map->cache_type == REGCACHE_NONE)
 242                 return 0;
 243
 244         BUG_ON(!map->cache_ops);
 245
 246         if (!regmap_volatile(map, reg))
 247                 return map->cache_ops->write(map, reg, value);
 248
 249         return 0;
 250 }
 251
 252 static bool regcache_reg_needs_sync(struct regmap *map, unsigned int reg,
 253                                     unsigned int val)
 254 {
 255         int ret;
 256
 257         /* If we don't know the chip just got reset, then sync everything. */
 258         if (!map->no_sync_defaults)
 259                 return true;
 260
 261         /* Is this the hardware default?  If so skip. */
 262         ret = regcache_lookup_reg(map, reg);
 263         if (ret >= 0 && val == map->reg_defaults[ret].def)
 264                 return false;
 265         return true;
 266 }
 267
 268 static int regcache_default_sync(struct regmap *map, unsigned int min,
 269                                  unsigned int max)
 270 {
 271         unsigned int reg;
 272
 273         for (reg = min; reg <= max; reg += map->reg_stride) {
 274                 unsigned int val;
 275                 int ret;
 276
 277                 if (regmap_volatile(map, reg) ||
 278                     !regmap_writeable(map, reg))
 279                         continue;
 280
 281                 ret = regcache_read(map, reg, &val);
 282                 if (ret)
 283                         return ret;
 284
 285                 if (!regcache_reg_needs_sync(map, reg, val))
 286                         continue;
 287
 288                 map->cache_bypass = true;
 289                 ret = _regmap_write(map, reg, val);
 290                 map->cache_bypass = false;
 291                 if (ret) {
 292                         dev_err(map->dev, "Unable to sync register %#x. %d\n",
 293                                 reg, ret);
 294                         return ret;
 295                 }
 296                 dev_dbg(map->dev, "Synced register %#x, value %#x\n", reg, val);
 297         }
 298
 299         return 0;
 300 }
 301
 302 /**
 303  * regcache_sync: Sync the register cache with the hardware.
 304  *
 305  * @map: map to configure.
 306  *
 307  * Any registers that should not be synced should be marked as
 308  * volatile.  In general drivers can choose not to use the provided
 309  * syncing functionality if they so require.
 310  *
 311  * Return a negative value on failure, 0 on success.
 312  */
 313 int regcache_sync(struct regmap *map)
 314 {
 315         int ret = 0;
 316         unsigned int i;
 317         const char *name;
 318         bool bypass;
 319
 320         BUG_ON(!map->cache_ops);
 321
 322         map->lock(map->lock_arg);
 323         /* Remember the initial bypass state */
 324         bypass = map->cache_bypass;
 325         dev_dbg(map->dev, "Syncing %s cache\n",
 326                 map->cache_ops->name);
 327         name = map->cache_ops->name;
 328         trace_regcache_sync(map, name, "start");
 329
 330         if (!map->cache_dirty)
 331                 goto out;
 332
 333         map->async = true;
 334
 335         /* Apply any patch first */
 336         map->cache_bypass = true;
 337         for (i = 0; i < map->patch_regs; i++) {
 338                 ret = _regmap_write(map, map->patch[i].reg, map->patch[i].def);
 339                 if (ret != 0) {
 340                         dev_err(map->dev, "Failed to write %x = %x: %d\n",
 341                                 map->patch[i].reg, map->patch[i].def, ret);
 342                         goto out;
 343                 }
 344         }
 345         map->cache_bypass = false;
 346
 347         if (map->cache_ops->sync)
 348                 ret = map->cache_ops->sync(map, 0, map->max_register);
 349         else
 350                 ret = regcache_default_sync(map, 0, map->max_register);
 351
 352         if (ret == 0)
 353                 map->cache_dirty = false;
 354
 355 out:
 356         /* Restore the bypass state */
 357         map->async = false;
 358         map->cache_bypass = bypass;
 359         map->no_sync_defaults = false;
 360         map->unlock(map->lock_arg);
 361
 362         regmap_async_complete(map);
 363
 364         trace_regcache_sync(map, name, "stop");
 365
 366         return ret;
 367 }
 368 EXPORT_SYMBOL_GPL(regcache_sync);
 369
 370 /**
 371  * regcache_sync_region: Sync part  of the register cache with the hardware.
 372  *
 373  * @map: map to sync.
 374  * @min: first register to sync
 375  * @max: last register to sync
 376  *
 377  * Write all non-default register values in the specified region to
 378  * the hardware.
 379  *
 380  * Return a negative value on failure, 0 on success.
 381  */
 382 int regcache_sync_region(struct regmap *map, unsigned int min,
 383                          unsigned int max)
 384 {
 385         int ret = 0;
 386         const char *name;
 387         bool bypass;
 388
 389         BUG_ON(!map->cache_ops);
 390
 391         map->lock(map->lock_arg);
 392
 393         /* Remember the initial bypass state */
 394         bypass = map->cache_bypass;
 395
 396         name = map->cache_ops->name;
 397         dev_dbg(map->dev, "Syncing %s cache from %d-%d\n", name, min, max);
 398
 399         trace_regcache_sync(map, name, "start region");
 400
 401         if (!map->cache_dirty)
 402                 goto out;
 403
 404         map->async = true;
 405
 406         if (map->cache_ops->sync)
 407                 ret = map->cache_ops->sync(map, min, max);
 408         else
 409                 ret = regcache_default_sync(map, min, max);
 410
 411 out:
 412         /* Restore the bypass state */
 413         map->cache_bypass = bypass;
 414         map->async = false;
 415         map->no_sync_defaults = false;
 416         map->unlock(map->lock_arg);
 417
 418         regmap_async_complete(map);
 419
 420         trace_regcache_sync(map, name, "stop region");
 421
 422         return ret;
 423 }
 424 EXPORT_SYMBOL_GPL(regcache_sync_region);
 425
 426 /**
 427  * regcache_drop_region: Discard part of the register cache
 428  *
 429  * @map: map to operate on
 430  * @min: first register to discard
 431  * @max: last register to discard
 432  *
 433  * Discard part of the register cache.
 434  *
 435  * Return a negative value on failure, 0 on success.
 436  */
 437 int regcache_drop_region(struct regmap *map, unsigned int min,
 438                          unsigned int max)
 439 {
 440         int ret = 0;
 441
 442         if (!map->cache_ops || !map->cache_ops->drop)
 443                 return -EINVAL;
 444
 445         map->lock(map->lock_arg);
 446
 447         trace_regcache_drop_region(map, min, max);
 448
 449         ret = map->cache_ops->drop(map, min, max);
 450
 451         map->unlock(map->lock_arg);
 452
 453         return ret;
 454 }
 455 EXPORT_SYMBOL_GPL(regcache_drop_region);
 456
 457 /**
 458  * regcache_cache_only: Put a register map into cache only mode
 459  *
 460  * @map: map to configure
 461  * @cache_only: flag if changes should be written to the hardware
 462  *
 463  * When a register map is marked as cache only writes to the register
 464  * map API will only update the register cache, they will not cause
 465  * any hardware changes.  This is useful for allowing portions of
 466  * drivers to act as though the device were functioning as normal when
 467  * it is disabled for power saving reasons.
 468  */
 469 void regcache_cache_only(struct regmap *map, bool enable)
 470 {
 471         map->lock(map->lock_arg);
 472         WARN_ON(map->cache_bypass && enable);
 473         map->cache_only = enable;
 474         trace_regmap_cache_only(map, enable);
 475         map->unlock(map->lock_arg);
 476 }
 477 EXPORT_SYMBOL_GPL(regcache_cache_only);
 478
 479 /**
 480  * regcache_mark_dirty: Indicate that HW registers were reset to default values
 481  *
 482  * @map: map to mark
 483  *
 484  * Inform regcache that the device has been powered down or reset, so that
 485  * on resume, regcache_sync() knows to write out all non-default values
 486  * stored in the cache.
 487  *
 488  * If this function is not called, regcache_sync() will assume that
 489  * the hardware state still matches the cache state, modulo any writes that
 490  * happened when cache_only was true.
 491  */
 492 void regcache_mark_dirty(struct regmap *map)
 493 {
 494         map->lock(map->lock_arg);
 495         map->cache_dirty = true;
 496         map->no_sync_defaults = true;
 497         map->unlock(map->lock_arg);
 498 }
 499 EXPORT_SYMBOL_GPL(regcache_mark_dirty);
 500
 501 /**
 502  * regcache_cache_bypass: Put a register map into cache bypass mode
 503  *
 504  * @map: map to configure
 505  * @cache_bypass: flag if changes should not be written to the hardware
 506  *
 507  * When a register map is marked with the cache bypass option, writes
 508  * to the register map API will only update the hardware and not the
 509  * the cache directly.  This is useful when syncing the cache back to
 510  * the hardware.
 511  */
 512 void regcache_cache_bypass(struct regmap *map, bool enable)
 513 {
 514         map->lock(map->lock_arg);
 515         WARN_ON(map->cache_only && enable);
 516         map->cache_bypass = enable;
 517         trace_regmap_cache_bypass(map, enable);
 518         map->unlock(map->lock_arg);
 519 }
 520 EXPORT_SYMBOL_GPL(regcache_cache_bypass);
 521
 522 bool regcache_set_val(struct regmap *map, void *base, unsigned int idx,
 523                       unsigned int val)
 524 {
 525         if (regcache_get_val(map, base, idx) == val)
 526                 return true;
 527
 528         /* Use device native format if possible */
 529         if (map->format.format_val) {
 530                 map->format.format_val(base + (map->cache_word_size * idx),
 531                                        val, 0);
 532                 return false;
 533         }
 534
 535         switch (map->cache_word_size) {
 536         case 1: {
 537                 u8 *cache = base;
 538                 cache[idx] = val;
 539                 break;
 540         }
 541         case 2: {
 542                 u16 *cache = base;
 543                 cache[idx] = val;
 544                 break;
 545         }
 546         case 4: {
 547                 u32 *cache = base;
 548                 cache[idx] = val;
 549                 break;
 550         }
 551         default:
 552                 BUG();
 553         }
 554         return false;
 555 }
 556
 557 unsigned int regcache_get_val(struct regmap *map, const void *base,
 558                               unsigned int idx)
 559 {
 560         if (!base)
 561                 return -EINVAL;
 562
 563         /* Use device native format if possible */
 564         if (map->format.parse_val)
 565                 return map->format.parse_val(regcache_get_val_addr(map, base,
 566                                                                    idx));
 567
 568         switch (map->cache_word_size) {
 569         case 1: {
 570                 const u8 *cache = base;
 571                 return cache[idx];
 572         }
 573         case 2: {
 574                 const u16 *cache = base;
 575                 return cache[idx];
 576         }
 577         case 4: {
 578                 const u32 *cache = base;
 579                 return cache[idx];
 580         }
 581         default:
 582                 BUG();
 583         }
 584         /* unreachable */
 585         return -1;
 586 }
 587
 588 static int regcache_default_cmp(const void *a, const void *b)
 589 {
 590         const struct reg_default *_a = a;
 591         const struct reg_default *_b = b;
 592
 593         return _a->reg - _b->reg;
 594 }
 595
 596 int regcache_lookup_reg(struct regmap *map, unsigned int reg)
 597 {
 598         struct reg_default key;
 599         struct reg_default *r;
 600
 601         key.reg = reg;
 602         key.def = 0;
 603
 604         r = bsearch(&key, map->reg_defaults, map->num_reg_defaults,
 605                     sizeof(struct reg_default), regcache_default_cmp);
 606
 607         if (r)
 608                 return r - map->reg_defaults;
 609         else
 610                 return -ENOENT;
 611 }
 612
 613 static bool regcache_reg_present(unsigned long *cache_present, unsigned int idx)
 614 {
 615         if (!cache_present)
 616                 return true;
 617
 618         return test_bit(idx, cache_present);
 619 }
 620
 621 static int regcache_sync_block_single(struct regmap *map, void *block,
 622                                       unsigned long *cache_present,
 623                                       unsigned int block_base,
 624                                       unsigned int start, unsigned int end)
 625 {
 626         unsigned int i, regtmp, val;
 627         int ret;
 628
 629         for (i = start; i < end; i++) {
 630                 regtmp = block_base + (i * map->reg_stride);
 631
 632                 if (!regcache_reg_present(cache_present, i) ||
 633                     !regmap_writeable(map, regtmp))
 634                         continue;
 635
 636                 val = regcache_get_val(map, block, i);
 637                 if (!regcache_reg_needs_sync(map, regtmp, val))
 638                         continue;
 639
 640                 map->cache_bypass = true;
 641
 642                 ret = _regmap_write(map, regtmp, val);
 643
 644                 map->cache_bypass = false;
 645                 if (ret != 0) {
 646                         dev_err(map->dev, "Unable to sync register %#x. %d\n",
 647                                 regtmp, ret);
 648                         return ret;
 649                 }
 650                 dev_dbg(map->dev, "Synced register %#x, value %#x\n",
 651                         regtmp, val);
 652         }
 653
 654         return 0;
 655 }
 656
 657 static int regcache_sync_block_raw_flush(struct regmap *map, const void **data,
 658                                          unsigned int base, unsigned int cur)
 659 {
 660         size_t val_bytes = map->format.val_bytes;
 661         int ret, count;
 662
 663         if (*data == NULL)
 664                 return 0;
 665
 666         count = (cur - base) / map->reg_stride;
 667
 668         dev_dbg(map->dev, "Writing %zu bytes for %d registers from 0x%x-0x%x\n",
 669                 count * val_bytes, count, base, cur - map->reg_stride);
 670
 671         map->cache_bypass = true;
 672
 673         ret = _regmap_raw_write(map, base, *data, count * val_bytes);
 674         if (ret)
 675                 dev_err(map->dev, "Unable to sync registers %#x-%#x. %d\n",
 676                         base, cur - map->reg_stride, ret);
 677
 678         map->cache_bypass = false;
 679
 680         *data = NULL;
 681
 682         return ret;
 683 }
 684
 685 static int regcache_sync_block_raw(struct regmap *map, void *block,
 686                             unsigned long *cache_present,
 687                             unsigned int block_base, unsigned int start,
 688                             unsigned int end)
 689 {
 690         unsigned int i, val;
 691         unsigned int regtmp = 0;
 692         unsigned int base = 0;
 693         const void *data = NULL;
 694         int ret;
 695
 696         for (i = start; i < end; i++) {
 697                 regtmp = block_base + (i * map->reg_stride);
 698
 699                 if (!regcache_reg_present(cache_present, i) ||
 700                     !regmap_writeable(map, regtmp)) {
 701                         ret = regcache_sync_block_raw_flush(map, &data,
 702                                                             base, regtmp);
 703                         if (ret != 0)
 704                                 return ret;
 705                         continue;
 706                 }
 707
 708                 val = regcache_get_val(map, block, i);
 709                 if (!regcache_reg_needs_sync(map, regtmp, val)) {
 710                         ret = regcache_sync_block_raw_flush(map, &data,
 711                                                             base, regtmp);
 712                         if (ret != 0)
 713                                 return ret;
 714                         continue;
 715                 }
 716
 717                 if (!data) {
 718                         data = regcache_get_val_addr(map, block, i);
 719                         base = regtmp;
 720                 }
 721         }
 722
 723         return regcache_sync_block_raw_flush(map, &data, base, regtmp +
 724                         map->reg_stride);
 725 }
 726
 727 int regcache_sync_block(struct regmap *map, void *block,
 728                         unsigned long *cache_present,
 729                         unsigned int block_base, unsigned int start,
 730                         unsigned int end)
 731 {
 732         if (regmap_can_raw_write(map) && !map->use_single_write)
 733                 return regcache_sync_block_raw(map, block, cache_present,
 734                                                block_base, start, end);
 735         else
 736                 return regcache_sync_block_single(map, block, cache_present,
 737                                                   block_base, start, end);
 738 }