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 };
  26
  27 static int regcache_hw_init(struct regmap *map)
  28 {
  29         int i, j;
  30         int ret;
  31         int count;
  32         unsigned int val;
  33         void *tmp_buf;
  34
  35         if (!map->num_reg_defaults_raw)
  36                 return -EINVAL;
  37
  38         if (!map->reg_defaults_raw) {
  39                 u32 cache_bypass = map->cache_bypass;
  40                 dev_warn(map->dev, "No cache defaults, reading back from HW\n");
  41
  42                 /* Bypass the cache access till data read from HW*/
  43                 map->cache_bypass = 1;
  44                 tmp_buf = kmalloc(map->cache_size_raw, GFP_KERNEL);
  45                 if (!tmp_buf)
  46                         return -EINVAL;
  47                 ret = regmap_bulk_read(map, 0, tmp_buf,
  48                                        map->num_reg_defaults_raw);
  49                 map->cache_bypass = cache_bypass;
  50                 if (ret < 0) {
  51                         kfree(tmp_buf);
  52                         return ret;
  53                 }
  54                 map->reg_defaults_raw = tmp_buf;
  55                 map->cache_free = 1;
  56         }
  57
  58         /* calculate the size of reg_defaults */
  59         for (count = 0, i = 0; i < map->num_reg_defaults_raw; i++) {
  60                 val = regcache_get_val(map->reg_defaults_raw,
  61                                        i, map->cache_word_size);
  62                 if (regmap_volatile(map, i))
  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->reg_defaults_raw,
  78                                        i, map->cache_word_size);
  79                 if (regmap_volatile(map, i))
  80                         continue;
  81                 map->reg_defaults[j].reg = i;
  82                 map->reg_defaults[j].def = val;
  83                 j++;
  84         }
  85
  86         return 0;
  87
  88 err_free:
  89         if (map->cache_free)
  90                 kfree(map->reg_defaults_raw);
  91
  92         return ret;
  93 }
  94
  95 int regcache_init(struct regmap *map, const struct regmap_config *config)
  96 {
  97         int ret;
  98         int i;
  99         void *tmp_buf;
 100
 101         if (map->cache_type == REGCACHE_NONE) {
 102                 map->cache_bypass = true;
 103                 return 0;
 104         }
 105
 106         for (i = 0; i < ARRAY_SIZE(cache_types); i++)
 107                 if (cache_types[i]->type == map->cache_type)
 108                         break;
 109
 110         if (i == ARRAY_SIZE(cache_types)) {
 111                 dev_err(map->dev, "Could not match compress type: %d\n",
 112                         map->cache_type);
 113                 return -EINVAL;
 114         }
 115
 116         map->num_reg_defaults = config->num_reg_defaults;
 117         map->num_reg_defaults_raw = config->num_reg_defaults_raw;
 118         map->reg_defaults_raw = config->reg_defaults_raw;
 119         map->cache_word_size = DIV_ROUND_UP(config->val_bits, 8);
 120         map->cache_size_raw = map->cache_word_size * config->num_reg_defaults_raw;
 121
 122         map->cache = NULL;
 123         map->cache_ops = cache_types[i];
 124
 125         if (!map->cache_ops->read ||
 126             !map->cache_ops->write ||
 127             !map->cache_ops->name)
 128                 return -EINVAL;
 129
 130         /* We still need to ensure that the reg_defaults
 131          * won't vanish from under us.  We'll need to make
 132          * a copy of it.
 133          */
 134         if (config->reg_defaults) {
 135                 if (!map->num_reg_defaults)
 136                         return -EINVAL;
 137                 tmp_buf = kmemdup(config->reg_defaults, map->num_reg_defaults *
 138                                   sizeof(struct reg_default), GFP_KERNEL);
 139                 if (!tmp_buf)
 140                         return -ENOMEM;
 141                 map->reg_defaults = tmp_buf;
 142         } else if (map->num_reg_defaults_raw) {
 143                 /* Some devices such as PMICs don't have cache defaults,
 144                  * we cope with this by reading back the HW registers and
 145                  * crafting the cache defaults by hand.
 146                  */
 147                 ret = regcache_hw_init(map);
 148                 if (ret < 0)
 149                         return ret;
 150         }
 151
 152         if (!map->max_register)
 153                 map->max_register = map->num_reg_defaults_raw;
 154
 155         if (map->cache_ops->init) {
 156                 dev_dbg(map->dev, "Initializing %s cache\n",
 157                         map->cache_ops->name);
 158                 ret = map->cache_ops->init(map);
 159                 if (ret)
 160                         goto err_free;
 161         }
 162         return 0;
 163
 164 err_free:
 165         kfree(map->reg_defaults);
 166         if (map->cache_free)
 167                 kfree(map->reg_defaults_raw);
 168
 169         return ret;
 170 }
 171
 172 void regcache_exit(struct regmap *map)
 173 {
 174         if (map->cache_type == REGCACHE_NONE)
 175                 return;
 176
 177         BUG_ON(!map->cache_ops);
 178
 179         kfree(map->reg_defaults);
 180         if (map->cache_free)
 181                 kfree(map->reg_defaults_raw);
 182
 183         if (map->cache_ops->exit) {
 184                 dev_dbg(map->dev, "Destroying %s cache\n",
 185                         map->cache_ops->name);
 186                 map->cache_ops->exit(map);
 187         }
 188 }
 189
 190 /**
 191  * regcache_read: Fetch the value of a given register from the cache.
 192  *
 193  * @map: map to configure.
 194  * @reg: The register index.
 195  * @value: The value to be returned.
 196  *
 197  * Return a negative value on failure, 0 on success.
 198  */
 199 int regcache_read(struct regmap *map,
 200                   unsigned int reg, unsigned int *value)
 201 {
 202         int ret;
 203
 204         if (map->cache_type == REGCACHE_NONE)
 205                 return -ENOSYS;
 206
 207         BUG_ON(!map->cache_ops);
 208
 209         if (!regmap_volatile(map, reg)) {
 210                 ret = map->cache_ops->read(map, reg, value);
 211
 212                 if (ret == 0)
 213                         trace_regmap_reg_read_cache(map->dev, reg, *value);
 214
 215                 return ret;
 216         }
 217
 218         return -EINVAL;
 219 }
 220
 221 /**
 222  * regcache_write: Set the value of a given register in the cache.
 223  *
 224  * @map: map to configure.
 225  * @reg: The register index.
 226  * @value: The new register value.
 227  *
 228  * Return a negative value on failure, 0 on success.
 229  */
 230 int regcache_write(struct regmap *map,
 231                    unsigned int reg, unsigned int value)
 232 {
 233         if (map->cache_type == REGCACHE_NONE)
 234                 return 0;
 235
 236         BUG_ON(!map->cache_ops);
 237
 238         if (!regmap_writeable(map, reg))
 239                 return -EIO;
 240
 241         if (!regmap_volatile(map, reg))
 242                 return map->cache_ops->write(map, reg, value);
 243
 244         return 0;
 245 }
 246
 247 /**
 248  * regcache_sync: Sync the register cache with the hardware.
 249  *
 250  * @map: map to configure.
 251  *
 252  * Any registers that should not be synced should be marked as
 253  * volatile.  In general drivers can choose not to use the provided
 254  * syncing functionality if they so require.
 255  *
 256  * Return a negative value on failure, 0 on success.
 257  */
 258 int regcache_sync(struct regmap *map)
 259 {
 260         int ret = 0;
 261         unsigned int i;
 262         const char *name;
 263         unsigned int bypass;
 264
 265         BUG_ON(!map->cache_ops || !map->cache_ops->sync);
 266
 267         mutex_lock(&map->lock);
 268         /* Remember the initial bypass state */
 269         bypass = map->cache_bypass;
 270         dev_dbg(map->dev, "Syncing %s cache\n",
 271                 map->cache_ops->name);
 272         name = map->cache_ops->name;
 273         trace_regcache_sync(map->dev, name, "start");
 274
 275         if (!map->cache_dirty)
 276                 goto out;
 277
 278         /* Apply any patch first */
 279         map->cache_bypass = 1;
 280         for (i = 0; i < map->patch_regs; i++) {
 281                 ret = _regmap_write(map, map->patch[i].reg, map->patch[i].def);
 282                 if (ret != 0) {
 283                         dev_err(map->dev, "Failed to write %x = %x: %d\n",
 284                                 map->patch[i].reg, map->patch[i].def, ret);
 285                         goto out;
 286                 }
 287         }
 288         map->cache_bypass = 0;
 289
 290         ret = map->cache_ops->sync(map, 0, map->max_register);
 291
 292         if (ret == 0)
 293                 map->cache_dirty = false;
 294
 295 out:
 296         trace_regcache_sync(map->dev, name, "stop");
 297         /* Restore the bypass state */
 298         map->cache_bypass = bypass;
 299         mutex_unlock(&map->lock);
 300
 301         return ret;
 302 }
 303 EXPORT_SYMBOL_GPL(regcache_sync);
 304
 305 /**
 306  * regcache_sync_region: Sync part  of the register cache with the hardware.
 307  *
 308  * @map: map to sync.
 309  * @min: first register to sync
 310  * @max: last register to sync
 311  *
 312  * Write all non-default register values in the specified region to
 313  * the hardware.
 314  *
 315  * Return a negative value on failure, 0 on success.
 316  */
 317 int regcache_sync_region(struct regmap *map, unsigned int min,
 318                          unsigned int max)
 319 {
 320         int ret = 0;
 321         const char *name;
 322         unsigned int bypass;
 323
 324         BUG_ON(!map->cache_ops || !map->cache_ops->sync);
 325
 326         mutex_lock(&map->lock);
 327
 328         /* Remember the initial bypass state */
 329         bypass = map->cache_bypass;
 330
 331         name = map->cache_ops->name;
 332         dev_dbg(map->dev, "Syncing %s cache from %d-%d\n", name, min, max);
 333
 334         trace_regcache_sync(map->dev, name, "start region");
 335
 336         if (!map->cache_dirty)
 337                 goto out;
 338
 339         ret = map->cache_ops->sync(map, min, max);
 340
 341 out:
 342         trace_regcache_sync(map->dev, name, "stop region");
 343         /* Restore the bypass state */
 344         map->cache_bypass = bypass;
 345         mutex_unlock(&map->lock);
 346
 347         return ret;
 348 }
 349 EXPORT_SYMBOL_GPL(regcache_sync_region);
 350
 351 /**
 352  * regcache_cache_only: Put a register map into cache only mode
 353  *
 354  * @map: map to configure
 355  * @cache_only: flag if changes should be written to the hardware
 356  *
 357  * When a register map is marked as cache only writes to the register
 358  * map API will only update the register cache, they will not cause
 359  * any hardware changes.  This is useful for allowing portions of
 360  * drivers to act as though the device were functioning as normal when
 361  * it is disabled for power saving reasons.
 362  */
 363 void regcache_cache_only(struct regmap *map, bool enable)
 364 {
 365         mutex_lock(&map->lock);
 366         WARN_ON(map->cache_bypass && enable);
 367         map->cache_only = enable;
 368         trace_regmap_cache_only(map->dev, enable);
 369         mutex_unlock(&map->lock);
 370 }
 371 EXPORT_SYMBOL_GPL(regcache_cache_only);
 372
 373 /**
 374  * regcache_mark_dirty: Mark the register cache as dirty
 375  *
 376  * @map: map to mark
 377  *
 378  * Mark the register cache as dirty, for example due to the device
 379  * having been powered down for suspend.  If the cache is not marked
 380  * as dirty then the cache sync will be suppressed.
 381  */
 382 void regcache_mark_dirty(struct regmap *map)
 383 {
 384         mutex_lock(&map->lock);
 385         map->cache_dirty = true;
 386         mutex_unlock(&map->lock);
 387 }
 388 EXPORT_SYMBOL_GPL(regcache_mark_dirty);
 389
 390 /**
 391  * regcache_cache_bypass: Put a register map into cache bypass mode
 392  *
 393  * @map: map to configure
 394  * @cache_bypass: flag if changes should not be written to the hardware
 395  *
 396  * When a register map is marked with the cache bypass option, writes
 397  * to the register map API will only update the hardware and not the
 398  * the cache directly.  This is useful when syncing the cache back to
 399  * the hardware.
 400  */
 401 void regcache_cache_bypass(struct regmap *map, bool enable)
 402 {
 403         mutex_lock(&map->lock);
 404         WARN_ON(map->cache_only && enable);
 405         map->cache_bypass = enable;
 406         trace_regmap_cache_bypass(map->dev, enable);
 407         mutex_unlock(&map->lock);
 408 }
 409 EXPORT_SYMBOL_GPL(regcache_cache_bypass);
 410
 411 bool regcache_set_val(void *base, unsigned int idx,
 412                       unsigned int val, unsigned int word_size)
 413 {
 414         switch (word_size) {
 415         case 1: {
 416                 u8 *cache = base;
 417                 if (cache[idx] == val)
 418                         return true;
 419                 cache[idx] = val;
 420                 break;
 421         }
 422         case 2: {
 423                 u16 *cache = base;
 424                 if (cache[idx] == val)
 425                         return true;
 426                 cache[idx] = val;
 427                 break;
 428         }
 429         case 4: {
 430                 u32 *cache = base;
 431                 if (cache[idx] == val)
 432                         return true;
 433                 cache[idx] = val;
 434                 break;
 435         }
 436         default:
 437                 BUG();
 438         }
 439         return false;
 440 }
 441
 442 unsigned int regcache_get_val(const void *base, unsigned int idx,
 443                               unsigned int word_size)
 444 {
 445         if (!base)
 446                 return -EINVAL;
 447
 448         switch (word_size) {
 449         case 1: {
 450                 const u8 *cache = base;
 451                 return cache[idx];
 452         }
 453         case 2: {
 454                 const u16 *cache = base;
 455                 return cache[idx];
 456         }
 457         case 4: {
 458                 const u32 *cache = base;
 459                 return cache[idx];
 460         }
 461         default:
 462                 BUG();
 463         }
 464         /* unreachable */
 465         return -1;
 466 }
 467
 468 static int regcache_default_cmp(const void *a, const void *b)
 469 {
 470         const struct reg_default *_a = a;
 471         const struct reg_default *_b = b;
 472
 473         return _a->reg - _b->reg;
 474 }
 475
 476 int regcache_lookup_reg(struct regmap *map, unsigned int reg)
 477 {
 478         struct reg_default key;
 479         struct reg_default *r;
 480
 481         key.reg = reg;
 482         key.def = 0;
 483
 484         r = bsearch(&key, map->reg_defaults, map->num_reg_defaults,
 485                     sizeof(struct reg_default), regcache_default_cmp);
 486
 487         if (r)
 488                 return r - map->reg_defaults;
 489         else
 490                 return -ENOENT;
 491 }