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 <trace/events/regmap.h>
  15
  16 #include "internal.h"
  17
  18 static const struct regcache_ops *cache_types[] = {
  19         &regcache_indexed_ops,
  20         &regcache_rbtree_ops,
  21         &regcache_lzo_ops,
  22 };
  23
  24 static int regcache_hw_init(struct regmap *map)
  25 {
  26         int i, j;
  27         int ret;
  28         int count;
  29         unsigned int val;
  30         void *tmp_buf;
  31
  32         if (!map->num_reg_defaults_raw)
  33                 return -EINVAL;
  34
  35         if (!map->reg_defaults_raw) {
  36                 dev_warn(map->dev, "No cache defaults, reading back from HW\n");
  37                 tmp_buf = kmalloc(map->cache_size_raw, GFP_KERNEL);
  38                 if (!tmp_buf)
  39                         return -EINVAL;
  40                 ret = regmap_bulk_read(map, 0, tmp_buf,
  41                                        map->num_reg_defaults_raw);
  42                 if (ret < 0) {
  43                         kfree(tmp_buf);
  44                         return ret;
  45                 }
  46                 map->reg_defaults_raw = tmp_buf;
  47                 map->cache_free = 1;
  48         }
  49
  50         /* calculate the size of reg_defaults */
  51         for (count = 0, i = 0; i < map->num_reg_defaults_raw; i++) {
  52                 val = regcache_get_val(map->reg_defaults_raw,
  53                                        i, map->cache_word_size);
  54                 if (!val)
  55                         continue;
  56                 count++;
  57         }
  58
  59         map->reg_defaults = kmalloc(count * sizeof(struct reg_default),
  60                                       GFP_KERNEL);
  61         if (!map->reg_defaults)
  62                 return -ENOMEM;
  63
  64         /* fill the reg_defaults */
  65         map->num_reg_defaults = count;
  66         for (i = 0, j = 0; i < map->num_reg_defaults_raw; i++) {
  67                 val = regcache_get_val(map->reg_defaults_raw,
  68                                        i, map->cache_word_size);
  69                 if (!val)
  70                         continue;
  71                 map->reg_defaults[j].reg = i;
  72                 map->reg_defaults[j].def = val;
  73                 j++;
  74         }
  75
  76         return 0;
  77 }
  78
  79 int regcache_init(struct regmap *map)
  80 {
  81         int ret;
  82         int i;
  83         void *tmp_buf;
  84
  85         if (map->cache_type == REGCACHE_NONE) {
  86                 map->cache_bypass = true;
  87                 return 0;
  88         }
  89
  90         for (i = 0; i < ARRAY_SIZE(cache_types); i++)
  91                 if (cache_types[i]->type == map->cache_type)
  92                         break;
  93
  94         if (i == ARRAY_SIZE(cache_types)) {
  95                 dev_err(map->dev, "Could not match compress type: %d\n",
  96                         map->cache_type);
  97                 return -EINVAL;
  98         }
  99
 100         map->cache = NULL;
 101         map->cache_ops = cache_types[i];
 102
 103         if (!map->cache_ops->read ||
 104             !map->cache_ops->write ||
 105             !map->cache_ops->name)
 106                 return -EINVAL;
 107
 108         /* We still need to ensure that the reg_defaults
 109          * won't vanish from under us.  We'll need to make
 110          * a copy of it.
 111          */
 112         if (map->reg_defaults) {
 113                 if (!map->num_reg_defaults)
 114                         return -EINVAL;
 115                 tmp_buf = kmemdup(map->reg_defaults, map->num_reg_defaults *
 116                                   sizeof(struct reg_default), GFP_KERNEL);
 117                 if (!tmp_buf)
 118                         return -ENOMEM;
 119                 map->reg_defaults = tmp_buf;
 120         } else {
 121                 /* Some devices such as PMICs don't have cache defaults,
 122                  * we cope with this by reading back the HW registers and
 123                  * crafting the cache defaults by hand.
 124                  */
 125                 ret = regcache_hw_init(map);
 126                 if (ret < 0)
 127                         return ret;
 128         }
 129
 130         if (!map->max_register)
 131                 map->max_register = map->num_reg_defaults_raw;
 132
 133         if (map->cache_ops->init) {
 134                 dev_dbg(map->dev, "Initializing %s cache\n",
 135                         map->cache_ops->name);
 136                 return map->cache_ops->init(map);
 137         }
 138         return 0;
 139 }
 140
 141 void regcache_exit(struct regmap *map)
 142 {
 143         if (map->cache_type == REGCACHE_NONE)
 144                 return;
 145
 146         BUG_ON(!map->cache_ops);
 147
 148         kfree(map->reg_defaults);
 149         if (map->cache_free)
 150                 kfree(map->reg_defaults_raw);
 151
 152         if (map->cache_ops->exit) {
 153                 dev_dbg(map->dev, "Destroying %s cache\n",
 154                         map->cache_ops->name);
 155                 map->cache_ops->exit(map);
 156         }
 157 }
 158
 159 /**
 160  * regcache_read: Fetch the value of a given register from the cache.
 161  *
 162  * @map: map to configure.
 163  * @reg: The register index.
 164  * @value: The value to be returned.
 165  *
 166  * Return a negative value on failure, 0 on success.
 167  */
 168 int regcache_read(struct regmap *map,
 169                   unsigned int reg, unsigned int *value)
 170 {
 171         if (map->cache_type == REGCACHE_NONE)
 172                 return -ENOSYS;
 173
 174         BUG_ON(!map->cache_ops);
 175
 176         if (!regmap_readable(map, reg))
 177                 return -EIO;
 178
 179         if (!regmap_volatile(map, reg))
 180                 return map->cache_ops->read(map, reg, value);
 181
 182         return -EINVAL;
 183 }
 184 EXPORT_SYMBOL_GPL(regcache_read);
 185
 186 /**
 187  * regcache_write: Set the value of a given register in the cache.
 188  *
 189  * @map: map to configure.
 190  * @reg: The register index.
 191  * @value: The new register value.
 192  *
 193  * Return a negative value on failure, 0 on success.
 194  */
 195 int regcache_write(struct regmap *map,
 196                    unsigned int reg, unsigned int value)
 197 {
 198         if (map->cache_type == REGCACHE_NONE)
 199                 return 0;
 200
 201         BUG_ON(!map->cache_ops);
 202
 203         if (!regmap_writeable(map, reg))
 204                 return -EIO;
 205
 206         if (!regmap_volatile(map, reg))
 207                 return map->cache_ops->write(map, reg, value);
 208
 209         return 0;
 210 }
 211 EXPORT_SYMBOL_GPL(regcache_write);
 212
 213 /**
 214  * regcache_sync: Sync the register cache with the hardware.
 215  *
 216  * @map: map to configure.
 217  *
 218  * Any registers that should not be synced should be marked as
 219  * volatile.  In general drivers can choose not to use the provided
 220  * syncing functionality if they so require.
 221  *
 222  * Return a negative value on failure, 0 on success.
 223  */
 224 int regcache_sync(struct regmap *map)
 225 {
 226         int ret = 0;
 227         unsigned int val;
 228         unsigned int i;
 229         const char *name;
 230
 231         BUG_ON(!map->cache_ops);
 232
 233         dev_dbg(map->dev, "Syncing %s cache\n",
 234                 map->cache_ops->name);
 235         name = map->cache_ops->name;
 236         trace_regcache_sync(map->dev, name, "start");
 237         if (map->cache_ops->sync) {
 238                 ret = map->cache_ops->sync(map);
 239         } else {
 240                 for (i = 0; i < map->num_reg_defaults; i++) {
 241                         ret = regcache_read(map, i, &val);
 242                         if (ret < 0)
 243                                 goto out;
 244                         map->cache_bypass = 1;
 245                         ret = regmap_write(map, i, val);
 246                         map->cache_bypass = 0;
 247                         if (ret < 0)
 248                                 goto out;
 249                         dev_dbg(map->dev, "Synced register %#x, value %#x\n",
 250                                 map->reg_defaults[i].reg,
 251                                 map->reg_defaults[i].def);
 252                 }
 253
 254         }
 255 out:
 256         trace_regcache_sync(map->dev, name, "stop");
 257
 258         return ret;
 259 }
 260 EXPORT_SYMBOL_GPL(regcache_sync);
 261
 262 /**
 263  * regcache_cache_only: Put a register map into cache only mode
 264  *
 265  * @map: map to configure
 266  * @cache_only: flag if changes should be written to the hardware
 267  *
 268  * When a register map is marked as cache only writes to the register
 269  * map API will only update the register cache, they will not cause
 270  * any hardware changes.  This is useful for allowing portions of
 271  * drivers to act as though the device were functioning as normal when
 272  * it is disabled for power saving reasons.
 273  */
 274 void regcache_cache_only(struct regmap *map, bool enable)
 275 {
 276         mutex_lock(&map->lock);
 277         map->cache_only = enable;
 278         mutex_unlock(&map->lock);
 279 }
 280 EXPORT_SYMBOL_GPL(regcache_cache_only);
 281
 282 bool regcache_set_val(void *base, unsigned int idx,
 283                       unsigned int val, unsigned int word_size)
 284 {
 285         switch (word_size) {
 286         case 1: {
 287                 u8 *cache = base;
 288                 if (cache[idx] == val)
 289                         return true;
 290                 cache[idx] = val;
 291                 break;
 292         }
 293         case 2: {
 294                 u16 *cache = base;
 295                 if (cache[idx] == val)
 296                         return true;
 297                 cache[idx] = val;
 298                 break;
 299         }
 300         default:
 301                 BUG();
 302         }
 303         /* unreachable */
 304         return false;
 305 }
 306
 307 unsigned int regcache_get_val(const void *base, unsigned int idx,
 308                               unsigned int word_size)
 309 {
 310         if (!base)
 311                 return -EINVAL;
 312
 313         switch (word_size) {
 314         case 1: {
 315                 const u8 *cache = base;
 316                 return cache[idx];
 317         }
 318         case 2: {
 319                 const u16 *cache = base;
 320                 return cache[idx];
 321         }
 322         default:
 323                 BUG();
 324         }
 325         /* unreachable */
 326         return -1;
 327 }
 328
 329 int regcache_lookup_reg(struct regmap *map, unsigned int reg)
 330 {
 331         unsigned int i;
 332
 333         for (i = 0; i < map->num_reg_defaults; i++)
 334                 if (map->reg_defaults[i].reg == reg)
 335                         return i;
 336         return -1;
 337 }
 338
 339 int regcache_insert_reg(struct regmap *map, unsigned int reg,
 340                         unsigned int val)
 341 {
 342         void *tmp;
 343
 344         tmp = krealloc(map->reg_defaults,
 345                        (map->num_reg_defaults + 1) * sizeof(struct reg_default),
 346                        GFP_KERNEL);
 347         if (!tmp)
 348                 return -ENOMEM;
 349         map->reg_defaults = tmp;
 350         map->num_reg_defaults++;
 351         map->reg_defaults[map->num_reg_defaults - 1].reg = reg;
 352         map->reg_defaults[map->num_reg_defaults - 1].def = val;
 353         return 0;
 354 }