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 <trace/events/regmap.h>
  16 #include <linux/bsearch.h>
  17 #include <linux/sort.h>
  18
  19 #include "internal.h"
  20
  21 static const struct regcache_ops *cache_types[] = {
  22         &regcache_rbtree_ops,
  23         &regcache_lzo_ops,
  24 };
  25
  26 static int regcache_hw_init(struct regmap *map)
  27 {
  28         int i, j;
  29         int ret;
  30         int count;
  31         unsigned int val;
  32         void *tmp_buf;
  33
  34         if (!map->num_reg_defaults_raw)
  35                 return -EINVAL;
  36
  37         if (!map->reg_defaults_raw) {
  38                 dev_warn(map->dev, "No cache defaults, reading back from HW\n");
  39                 tmp_buf = kmalloc(map->cache_size_raw, GFP_KERNEL);
  40                 if (!tmp_buf)
  41                         return -EINVAL;
  42                 ret = regmap_bulk_read(map, 0, tmp_buf,
  43                                        map->num_reg_defaults_raw);
  44                 if (ret < 0) {
  45                         kfree(tmp_buf);
  46                         return ret;
  47                 }
  48                 map->reg_defaults_raw = tmp_buf;
  49                 map->cache_free = 1;
  50         }
  51
  52         /* calculate the size of reg_defaults */
  53         for (count = 0, i = 0; i < map->num_reg_defaults_raw; i++) {
  54                 val = regcache_get_val(map->reg_defaults_raw,
  55                                        i, map->cache_word_size);
  56                 if (!val)
  57                         continue;
  58                 count++;
  59         }
  60
  61         map->reg_defaults = kmalloc(count * sizeof(struct reg_default),
  62                                       GFP_KERNEL);
  63         if (!map->reg_defaults) {
  64                 ret = -ENOMEM;
  65                 goto err_free;
  66         }
  67
  68         /* fill the reg_defaults */
  69         map->num_reg_defaults = count;
  70         for (i = 0, j = 0; i < map->num_reg_defaults_raw; i++) {
  71                 val = regcache_get_val(map->reg_defaults_raw,
  72                                        i, map->cache_word_size);
  73                 if (!val)
  74                         continue;
  75                 map->reg_defaults[j].reg = i;
  76                 map->reg_defaults[j].def = val;
  77                 j++;
  78         }
  79
  80         return 0;
  81
  82 err_free:
  83         if (map->cache_free)
  84                 kfree(map->reg_defaults_raw);
  85
  86         return ret;
  87 }
  88
  89 int regcache_init(struct regmap *map, const struct regmap_config *config)
  90 {
  91         int ret;
  92         int i;
  93         void *tmp_buf;
  94
  95         if (map->cache_type == REGCACHE_NONE) {
  96                 map->cache_bypass = true;
  97                 return 0;
  98         }
  99
 100         for (i = 0; i < ARRAY_SIZE(cache_types); i++)
 101                 if (cache_types[i]->type == map->cache_type)
 102                         break;
 103
 104         if (i == ARRAY_SIZE(cache_types)) {
 105                 dev_err(map->dev, "Could not match compress type: %d\n",
 106                         map->cache_type);
 107                 return -EINVAL;
 108         }
 109
 110         map->num_reg_defaults = config->num_reg_defaults;
 111         map->num_reg_defaults_raw = config->num_reg_defaults_raw;
 112         map->reg_defaults_raw = config->reg_defaults_raw;
 113         map->cache_word_size = DIV_ROUND_UP(config->val_bits, 8);
 114         map->cache_size_raw = map->cache_word_size * config->num_reg_defaults_raw;
 115
 116         map->cache = NULL;
 117         map->cache_ops = cache_types[i];
 118
 119         if (!map->cache_ops->read ||
 120             !map->cache_ops->write ||
 121             !map->cache_ops->name)
 122                 return -EINVAL;
 123
 124         /* We still need to ensure that the reg_defaults
 125          * won't vanish from under us.  We'll need to make
 126          * a copy of it.
 127          */
 128         if (config->reg_defaults) {
 129                 if (!map->num_reg_defaults)
 130                         return -EINVAL;
 131                 tmp_buf = kmemdup(config->reg_defaults, map->num_reg_defaults *
 132                                   sizeof(struct reg_default), GFP_KERNEL);
 133                 if (!tmp_buf)
 134                         return -ENOMEM;
 135                 map->reg_defaults = tmp_buf;
 136         } else if (map->num_reg_defaults_raw) {
 137                 /* Some devices such as PMICs don't have cache defaults,
 138                  * we cope with this by reading back the HW registers and
 139                  * crafting the cache defaults by hand.
 140                  */
 141                 ret = regcache_hw_init(map);
 142                 if (ret < 0)
 143                         return ret;
 144         }
 145
 146         if (!map->max_register)
 147                 map->max_register = map->num_reg_defaults_raw;
 148
 149         if (map->cache_ops->init) {
 150                 dev_dbg(map->dev, "Initializing %s cache\n",
 151                         map->cache_ops->name);
 152                 ret = map->cache_ops->init(map);
 153                 if (ret)
 154                         goto err_free;
 155         }
 156         return 0;
 157
 158 err_free:
 159         kfree(map->reg_defaults);
 160         if (map->cache_free)
 161                 kfree(map->reg_defaults_raw);
 162
 163         return ret;
 164 }
 165
 166 void regcache_exit(struct regmap *map)
 167 {
 168         if (map->cache_type == REGCACHE_NONE)
 169                 return;
 170
 171         BUG_ON(!map->cache_ops);
 172
 173         kfree(map->reg_defaults);
 174         if (map->cache_free)
 175                 kfree(map->reg_defaults_raw);
 176
 177         if (map->cache_ops->exit) {
 178                 dev_dbg(map->dev, "Destroying %s cache\n",
 179                         map->cache_ops->name);
 180                 map->cache_ops->exit(map);
 181         }
 182 }
 183
 184 /**
 185  * regcache_read: Fetch the value of a given register from the cache.
 186  *
 187  * @map: map to configure.
 188  * @reg: The register index.
 189  * @value: The value to be returned.
 190  *
 191  * Return a negative value on failure, 0 on success.
 192  */
 193 int regcache_read(struct regmap *map,
 194                   unsigned int reg, unsigned int *value)
 195 {
 196         int ret;
 197
 198         if (map->cache_type == REGCACHE_NONE)
 199                 return -ENOSYS;
 200
 201         BUG_ON(!map->cache_ops);
 202
 203         if (!regmap_volatile(map, reg)) {
 204                 ret = map->cache_ops->read(map, reg, value);
 205
 206                 if (ret == 0)
 207                         trace_regmap_reg_read_cache(map->dev, reg, *value);
 208
 209                 return ret;
 210         }
 211
 212         return -EINVAL;
 213 }
 214 EXPORT_SYMBOL_GPL(regcache_read);
 215
 216 /**
 217  * regcache_write: Set the value of a given register in the cache.
 218  *
 219  * @map: map to configure.
 220  * @reg: The register index.
 221  * @value: The new register value.
 222  *
 223  * Return a negative value on failure, 0 on success.
 224  */
 225 int regcache_write(struct regmap *map,
 226                    unsigned int reg, unsigned int value)
 227 {
 228         if (map->cache_type == REGCACHE_NONE)
 229                 return 0;
 230
 231         BUG_ON(!map->cache_ops);
 232
 233         if (!regmap_writeable(map, reg))
 234                 return -EIO;
 235
 236         if (!regmap_volatile(map, reg))
 237                 return map->cache_ops->write(map, reg, value);
 238
 239         return 0;
 240 }
 241 EXPORT_SYMBOL_GPL(regcache_write);
 242
 243 /**
 244  * regcache_sync: Sync the register cache with the hardware.
 245  *
 246  * @map: map to configure.
 247  *
 248  * Any registers that should not be synced should be marked as
 249  * volatile.  In general drivers can choose not to use the provided
 250  * syncing functionality if they so require.
 251  *
 252  * Return a negative value on failure, 0 on success.
 253  */
 254 int regcache_sync(struct regmap *map)
 255 {
 256         int ret = 0;
 257         unsigned int val;
 258         unsigned int i;
 259         const char *name;
 260         unsigned int bypass;
 261
 262         BUG_ON(!map->cache_ops);
 263
 264         mutex_lock(&map->lock);
 265         /* Remember the initial bypass state */
 266         bypass = map->cache_bypass;
 267         dev_dbg(map->dev, "Syncing %s cache\n",
 268                 map->cache_ops->name);
 269         name = map->cache_ops->name;
 270         trace_regcache_sync(map->dev, name, "start");
 271         if (!map->cache_dirty)
 272                 goto out;
 273         if (map->cache_ops->sync) {
 274                 ret = map->cache_ops->sync(map);
 275         } else {
 276                 for (i = 0; i < map->num_reg_defaults; i++) {
 277                         ret = regcache_read(map, i, &val);
 278                         if (ret < 0)
 279                                 goto out;
 280                         map->cache_bypass = 1;
 281                         ret = _regmap_write(map, i, val);
 282                         map->cache_bypass = 0;
 283                         if (ret < 0)
 284                                 goto out;
 285                         dev_dbg(map->dev, "Synced register %#x, value %#x\n",
 286                                 map->reg_defaults[i].reg,
 287                                 map->reg_defaults[i].def);
 288                 }
 289
 290         }
 291 out:
 292         trace_regcache_sync(map->dev, name, "stop");
 293         /* Restore the bypass state */
 294         map->cache_bypass = bypass;
 295         mutex_unlock(&map->lock);
 296
 297         return ret;
 298 }
 299 EXPORT_SYMBOL_GPL(regcache_sync);
 300
 301 /**
 302  * regcache_cache_only: Put a register map into cache only mode
 303  *
 304  * @map: map to configure
 305  * @cache_only: flag if changes should be written to the hardware
 306  *
 307  * When a register map is marked as cache only writes to the register
 308  * map API will only update the register cache, they will not cause
 309  * any hardware changes.  This is useful for allowing portions of
 310  * drivers to act as though the device were functioning as normal when
 311  * it is disabled for power saving reasons.
 312  */
 313 void regcache_cache_only(struct regmap *map, bool enable)
 314 {
 315         mutex_lock(&map->lock);
 316         WARN_ON(map->cache_bypass && enable);
 317         map->cache_only = enable;
 318         mutex_unlock(&map->lock);
 319 }
 320 EXPORT_SYMBOL_GPL(regcache_cache_only);
 321
 322 /**
 323  * regcache_mark_dirty: Mark the register cache as dirty
 324  *
 325  * @map: map to mark
 326  *
 327  * Mark the register cache as dirty, for example due to the device
 328  * having been powered down for suspend.  If the cache is not marked
 329  * as dirty then the cache sync will be suppressed.
 330  */
 331 void regcache_mark_dirty(struct regmap *map)
 332 {
 333         mutex_lock(&map->lock);
 334         map->cache_dirty = true;
 335         mutex_unlock(&map->lock);
 336 }
 337 EXPORT_SYMBOL_GPL(regcache_mark_dirty);
 338
 339 /**
 340  * regcache_cache_bypass: Put a register map into cache bypass mode
 341  *
 342  * @map: map to configure
 343  * @cache_bypass: flag if changes should not be written to the hardware
 344  *
 345  * When a register map is marked with the cache bypass option, writes
 346  * to the register map API will only update the hardware and not the
 347  * the cache directly.  This is useful when syncing the cache back to
 348  * the hardware.
 349  */
 350 void regcache_cache_bypass(struct regmap *map, bool enable)
 351 {
 352         mutex_lock(&map->lock);
 353         WARN_ON(map->cache_only && enable);
 354         map->cache_bypass = enable;
 355         mutex_unlock(&map->lock);
 356 }
 357 EXPORT_SYMBOL_GPL(regcache_cache_bypass);
 358
 359 bool regcache_set_val(void *base, unsigned int idx,
 360                       unsigned int val, unsigned int word_size)
 361 {
 362         switch (word_size) {
 363         case 1: {
 364                 u8 *cache = base;
 365                 if (cache[idx] == val)
 366                         return true;
 367                 cache[idx] = val;
 368                 break;
 369         }
 370         case 2: {
 371                 u16 *cache = base;
 372                 if (cache[idx] == val)
 373                         return true;
 374                 cache[idx] = val;
 375                 break;
 376         }
 377         default:
 378                 BUG();
 379         }
 380         /* unreachable */
 381         return false;
 382 }
 383
 384 unsigned int regcache_get_val(const void *base, unsigned int idx,
 385                               unsigned int word_size)
 386 {
 387         if (!base)
 388                 return -EINVAL;
 389
 390         switch (word_size) {
 391         case 1: {
 392                 const u8 *cache = base;
 393                 return cache[idx];
 394         }
 395         case 2: {
 396                 const u16 *cache = base;
 397                 return cache[idx];
 398         }
 399         default:
 400                 BUG();
 401         }
 402         /* unreachable */
 403         return -1;
 404 }
 405
 406 static int regcache_default_cmp(const void *a, const void *b)
 407 {
 408         const struct reg_default *_a = a;
 409         const struct reg_default *_b = b;
 410
 411         return _a->reg - _b->reg;
 412 }
 413
 414 int regcache_lookup_reg(struct regmap *map, unsigned int reg)
 415 {
 416         struct reg_default key;
 417         struct reg_default *r;
 418
 419         key.reg = reg;
 420         key.def = 0;
 421
 422         r = bsearch(&key, map->reg_defaults, map->num_reg_defaults,
 423                     sizeof(struct reg_default), regcache_default_cmp);
 424
 425         if (r)
 426                 return r - map->reg_defaults;
 427         else
 428                 return -ENOENT;
 429 }