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 ®cache_rbtree_ops, 23 ®cache_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 } 430