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_bulk_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->reg_defaults_raw,
  62                                        i, map->cache_word_size);
  63                 if (regmap_volatile(map, i * map->reg_stride))
  64                         continue;
  65                 count++;
  66         }
  67
  68         map->reg_defaults = kmalloc(count * sizeof(struct reg_default),
  69                                       GFP_KERNEL);
  70         if (!map->reg_defaults) {
  71                 ret = -ENOMEM;
  72                 goto err_free;
  73         }
  74
  75         /* fill the reg_defaults */
  76         map->num_reg_defaults = count;
  77         for (i = 0, j = 0; i < map->num_reg_defaults_raw; i++) {
  78                 val = regcache_get_val(map->reg_defaults_raw,
  79                                        i, map->cache_word_size);
  80                 if (regmap_volatile(map, i * map->reg_stride))
  81                         continue;
  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_free:
  90         if (map->cache_free)
  91                 kfree(map->reg_defaults_raw);
  92
  93         return ret;
  94 }
  95
  96 int regcache_init(struct regmap *map, const struct regmap_config *config)
  97 {
  98         int ret;
  99         int i;
 100         void *tmp_buf;
 101
 102         for (i = 0; i < config->num_reg_defaults; i++)
 103                 if (config->reg_defaults[i].reg % map->reg_stride)
 104                         return -EINVAL;
 105
 106         if (map->cache_type == REGCACHE_NONE) {
 107                 map->cache_bypass = true;
 108                 return 0;
 109         }
 110
 111         for (i = 0; i < ARRAY_SIZE(cache_types); i++)
 112                 if (cache_types[i]->type == map->cache_type)
 113                         break;
 114
 115         if (i == ARRAY_SIZE(cache_types)) {
 116                 dev_err(map->dev, "Could not match compress type: %d\n",
 117                         map->cache_type);
 118                 return -EINVAL;
 119         }
 120
 121         map->num_reg_defaults = config->num_reg_defaults;
 122         map->num_reg_defaults_raw = config->num_reg_defaults_raw;
 123         map->reg_defaults_raw = config->reg_defaults_raw;
 124         map->cache_word_size = DIV_ROUND_UP(config->val_bits, 8);
 125         map->cache_size_raw = map->cache_word_size * config->num_reg_defaults_raw;
 126
 127         map->cache = NULL;
 128         map->cache_ops = cache_types[i];
 129
 130         if (!map->cache_ops->read ||
 131             !map->cache_ops->write ||
 132             !map->cache_ops->name)
 133                 return -EINVAL;
 134
 135         /* We still need to ensure that the reg_defaults
 136          * won't vanish from under us.  We'll need to make
 137          * a copy of it.
 138          */
 139         if (config->reg_defaults) {
 140                 if (!map->num_reg_defaults)
 141                         return -EINVAL;
 142                 tmp_buf = kmemdup(config->reg_defaults, map->num_reg_defaults *
 143                                   sizeof(struct reg_default), GFP_KERNEL);
 144                 if (!tmp_buf)
 145                         return -ENOMEM;
 146                 map->reg_defaults = tmp_buf;
 147         } else if (map->num_reg_defaults_raw) {
 148                 /* Some devices such as PMICs don't have cache defaults,
 149                  * we cope with this by reading back the HW registers and
 150                  * crafting the cache defaults by hand.
 151                  */
 152                 ret = regcache_hw_init(map);
 153                 if (ret < 0)
 154                         return ret;
 155         }
 156
 157         if (!map->max_register)
 158                 map->max_register = map->num_reg_defaults_raw;
 159
 160         if (map->cache_ops->init) {
 161                 dev_dbg(map->dev, "Initializing %s cache\n",
 162                         map->cache_ops->name);
 163                 ret = map->cache_ops->init(map);
 164                 if (ret)
 165                         goto err_free;
 166         }
 167         return 0;
 168
 169 err_free:
 170         kfree(map->reg_defaults);
 171         if (map->cache_free)
 172                 kfree(map->reg_defaults_raw);
 173
 174         return ret;
 175 }
 176
 177 void regcache_exit(struct regmap *map)
 178 {
 179         if (map->cache_type == REGCACHE_NONE)
 180                 return;
 181
 182         BUG_ON(!map->cache_ops);
 183
 184         kfree(map->reg_defaults);
 185         if (map->cache_free)
 186                 kfree(map->reg_defaults_raw);
 187
 188         if (map->cache_ops->exit) {
 189                 dev_dbg(map->dev, "Destroying %s cache\n",
 190                         map->cache_ops->name);
 191                 map->cache_ops->exit(map);
 192         }
 193 }
 194
 195 /**
 196  * regcache_read: Fetch the value of a given register from the cache.
 197  *
 198  * @map: map to configure.
 199  * @reg: The register index.
 200  * @value: The value to be returned.
 201  *
 202  * Return a negative value on failure, 0 on success.
 203  */
 204 int regcache_read(struct regmap *map,
 205                   unsigned int reg, unsigned int *value)
 206 {
 207         int ret;
 208
 209         if (map->cache_type == REGCACHE_NONE)
 210                 return -ENOSYS;
 211
 212         BUG_ON(!map->cache_ops);
 213
 214         if (!regmap_volatile(map, reg)) {
 215                 ret = map->cache_ops->read(map, reg, value);
 216
 217                 if (ret == 0)
 218                         trace_regmap_reg_read_cache(map->dev, reg, *value);
 219
 220                 return ret;
 221         }
 222
 223         return -EINVAL;
 224 }
 225
 226 /**
 227  * regcache_write: Set the value of a given register in the cache.
 228  *
 229  * @map: map to configure.
 230  * @reg: The register index.
 231  * @value: The new register value.
 232  *
 233  * Return a negative value on failure, 0 on success.
 234  */
 235 int regcache_write(struct regmap *map,
 236                    unsigned int reg, unsigned int value)
 237 {
 238         if (map->cache_type == REGCACHE_NONE)
 239                 return 0;
 240
 241         BUG_ON(!map->cache_ops);
 242
 243         if (!regmap_writeable(map, reg))
 244                 return -EIO;
 245
 246         if (!regmap_volatile(map, reg))
 247                 return map->cache_ops->write(map, reg, value);
 248
 249         return 0;
 250 }
 251
 252 /**
 253  * regcache_sync: Sync the register cache with the hardware.
 254  *
 255  * @map: map to configure.
 256  *
 257  * Any registers that should not be synced should be marked as
 258  * volatile.  In general drivers can choose not to use the provided
 259  * syncing functionality if they so require.
 260  *
 261  * Return a negative value on failure, 0 on success.
 262  */
 263 int regcache_sync(struct regmap *map)
 264 {
 265         int ret = 0;
 266         unsigned int i;
 267         const char *name;
 268         unsigned int bypass;
 269
 270         BUG_ON(!map->cache_ops || !map->cache_ops->sync);
 271
 272         map->lock(map);
 273         /* Remember the initial bypass state */
 274         bypass = map->cache_bypass;
 275         dev_dbg(map->dev, "Syncing %s cache\n",
 276                 map->cache_ops->name);
 277         name = map->cache_ops->name;
 278         trace_regcache_sync(map->dev, name, "start");
 279
 280         if (!map->cache_dirty)
 281                 goto out;
 282
 283         /* Apply any patch first */
 284         map->cache_bypass = 1;
 285         for (i = 0; i < map->patch_regs; i++) {
 286                 if (map->patch[i].reg % map->reg_stride) {
 287                         ret = -EINVAL;
 288                         goto out;
 289                 }
 290                 ret = _regmap_write(map, map->patch[i].reg, map->patch[i].def);
 291                 if (ret != 0) {
 292                         dev_err(map->dev, "Failed to write %x = %x: %d\n",
 293                                 map->patch[i].reg, map->patch[i].def, ret);
 294                         goto out;
 295                 }
 296         }
 297         map->cache_bypass = 0;
 298
 299         ret = map->cache_ops->sync(map, 0, map->max_register);
 300
 301         if (ret == 0)
 302                 map->cache_dirty = false;
 303
 304 out:
 305         trace_regcache_sync(map->dev, name, "stop");
 306         /* Restore the bypass state */
 307         map->cache_bypass = bypass;
 308         map->unlock(map);
 309
 310         return ret;
 311 }
 312 EXPORT_SYMBOL_GPL(regcache_sync);
 313
 314 /**
 315  * regcache_sync_region: Sync part  of the register cache with the hardware.
 316  *
 317  * @map: map to sync.
 318  * @min: first register to sync
 319  * @max: last register to sync
 320  *
 321  * Write all non-default register values in the specified region to
 322  * the hardware.
 323  *
 324  * Return a negative value on failure, 0 on success.
 325  */
 326 int regcache_sync_region(struct regmap *map, unsigned int min,
 327                          unsigned int max)
 328 {
 329         int ret = 0;
 330         const char *name;
 331         unsigned int bypass;
 332
 333         BUG_ON(!map->cache_ops || !map->cache_ops->sync);
 334
 335         map->lock(map);
 336
 337         /* Remember the initial bypass state */
 338         bypass = map->cache_bypass;
 339
 340         name = map->cache_ops->name;
 341         dev_dbg(map->dev, "Syncing %s cache from %d-%d\n", name, min, max);
 342
 343         trace_regcache_sync(map->dev, name, "start region");
 344
 345         if (!map->cache_dirty)
 346                 goto out;
 347
 348         ret = map->cache_ops->sync(map, min, max);
 349
 350 out:
 351         trace_regcache_sync(map->dev, name, "stop region");
 352         /* Restore the bypass state */
 353         map->cache_bypass = bypass;
 354         map->unlock(map);
 355
 356         return ret;
 357 }
 358 EXPORT_SYMBOL_GPL(regcache_sync_region);
 359
 360 /**
 361  * regcache_cache_only: Put a register map into cache only mode
 362  *
 363  * @map: map to configure
 364  * @cache_only: flag if changes should be written to the hardware
 365  *
 366  * When a register map is marked as cache only writes to the register
 367  * map API will only update the register cache, they will not cause
 368  * any hardware changes.  This is useful for allowing portions of
 369  * drivers to act as though the device were functioning as normal when
 370  * it is disabled for power saving reasons.
 371  */
 372 void regcache_cache_only(struct regmap *map, bool enable)
 373 {
 374         map->lock(map);
 375         WARN_ON(map->cache_bypass && enable);
 376         map->cache_only = enable;
 377         trace_regmap_cache_only(map->dev, enable);
 378         map->unlock(map);
 379 }
 380 EXPORT_SYMBOL_GPL(regcache_cache_only);
 381
 382 /**
 383  * regcache_mark_dirty: Mark the register cache as dirty
 384  *
 385  * @map: map to mark
 386  *
 387  * Mark the register cache as dirty, for example due to the device
 388  * having been powered down for suspend.  If the cache is not marked
 389  * as dirty then the cache sync will be suppressed.
 390  */
 391 void regcache_mark_dirty(struct regmap *map)
 392 {
 393         map->lock(map);
 394         map->cache_dirty = true;
 395         map->unlock(map);
 396 }
 397 EXPORT_SYMBOL_GPL(regcache_mark_dirty);
 398
 399 /**
 400  * regcache_cache_bypass: Put a register map into cache bypass mode
 401  *
 402  * @map: map to configure
 403  * @cache_bypass: flag if changes should not be written to the hardware
 404  *
 405  * When a register map is marked with the cache bypass option, writes
 406  * to the register map API will only update the hardware and not the
 407  * the cache directly.  This is useful when syncing the cache back to
 408  * the hardware.
 409  */
 410 void regcache_cache_bypass(struct regmap *map, bool enable)
 411 {
 412         map->lock(map);
 413         WARN_ON(map->cache_only && enable);
 414         map->cache_bypass = enable;
 415         trace_regmap_cache_bypass(map->dev, enable);
 416         map->unlock(map);
 417 }
 418 EXPORT_SYMBOL_GPL(regcache_cache_bypass);
 419
 420 bool regcache_set_val(void *base, unsigned int idx,
 421                       unsigned int val, unsigned int word_size)
 422 {
 423         switch (word_size) {
 424         case 1: {
 425                 u8 *cache = base;
 426                 if (cache[idx] == val)
 427                         return true;
 428                 cache[idx] = val;
 429                 break;
 430         }
 431         case 2: {
 432                 u16 *cache = base;
 433                 if (cache[idx] == val)
 434                         return true;
 435                 cache[idx] = val;
 436                 break;
 437         }
 438         case 4: {
 439                 u32 *cache = base;
 440                 if (cache[idx] == val)
 441                         return true;
 442                 cache[idx] = val;
 443                 break;
 444         }
 445         default:
 446                 BUG();
 447         }
 448         return false;
 449 }
 450
 451 unsigned int regcache_get_val(const void *base, unsigned int idx,
 452                               unsigned int word_size)
 453 {
 454         if (!base)
 455                 return -EINVAL;
 456
 457         switch (word_size) {
 458         case 1: {
 459                 const u8 *cache = base;
 460                 return cache[idx];
 461         }
 462         case 2: {
 463                 const u16 *cache = base;
 464                 return cache[idx];
 465         }
 466         case 4: {
 467                 const u32 *cache = base;
 468                 return cache[idx];
 469         }
 470         default:
 471                 BUG();
 472         }
 473         /* unreachable */
 474         return -1;
 475 }
 476
 477 static int regcache_default_cmp(const void *a, const void *b)
 478 {
 479         const struct reg_default *_a = a;
 480         const struct reg_default *_b = b;
 481
 482         return _a->reg - _b->reg;
 483 }
 484
 485 int regcache_lookup_reg(struct regmap *map, unsigned int reg)
 486 {
 487         struct reg_default key;
 488         struct reg_default *r;
 489
 490         key.reg = reg;
 491         key.def = 0;
 492
 493         r = bsearch(&key, map->reg_defaults, map->num_reg_defaults,
 494                     sizeof(struct reg_default), regcache_default_cmp);
 495
 496         if (r)
 497                 return r - map->reg_defaults;
 498         else
 499                 return -ENOENT;
 500 }