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