diff options
Diffstat (limited to 'drivers/base/regmap/regcache.c')
| -rw-r--r-- | drivers/base/regmap/regcache.c | 402 |
1 files changed, 402 insertions, 0 deletions
diff --git a/drivers/base/regmap/regcache.c b/drivers/base/regmap/regcache.c new file mode 100644 index 000000000000..666f6f5011dc --- /dev/null +++ b/drivers/base/regmap/regcache.c @@ -0,0 +1,402 @@ +/* + * Register cache access API + * + * Copyright 2011 Wolfson Microelectronics plc + * + * Author: Dimitris Papastamos <dp@opensource.wolfsonmicro.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/slab.h> +#include <linux/export.h> +#include <trace/events/regmap.h> +#include <linux/bsearch.h> +#include <linux/sort.h> + +#include "internal.h" + +static const struct regcache_ops *cache_types[] = { + ®cache_indexed_ops, + ®cache_rbtree_ops, + ®cache_lzo_ops, +}; + +static int regcache_hw_init(struct regmap *map) +{ + int i, j; + int ret; + int count; + unsigned int val; + void *tmp_buf; + + if (!map->num_reg_defaults_raw) + return -EINVAL; + + if (!map->reg_defaults_raw) { + dev_warn(map->dev, "No cache defaults, reading back from HW\n"); + tmp_buf = kmalloc(map->cache_size_raw, GFP_KERNEL); + if (!tmp_buf) + return -EINVAL; + ret = regmap_bulk_read(map, 0, tmp_buf, + map->num_reg_defaults_raw); + if (ret < 0) { + kfree(tmp_buf); + return ret; + } + map->reg_defaults_raw = tmp_buf; + map->cache_free = 1; + } + + /* calculate the size of reg_defaults */ + for (count = 0, i = 0; i < map->num_reg_defaults_raw; i++) { + val = regcache_get_val(map->reg_defaults_raw, + i, map->cache_word_size); + if (!val) + continue; + count++; + } + + map->reg_defaults = kmalloc(count * sizeof(struct reg_default), + GFP_KERNEL); + if (!map->reg_defaults) + return -ENOMEM; + + /* fill the reg_defaults */ + map->num_reg_defaults = count; + for (i = 0, j = 0; i < map->num_reg_defaults_raw; i++) { + val = regcache_get_val(map->reg_defaults_raw, + i, map->cache_word_size); + if (!val) + continue; + map->reg_defaults[j].reg = i; + map->reg_defaults[j].def = val; + j++; + } + + return 0; +} + +int regcache_init(struct regmap *map) +{ + int ret; + int i; + void *tmp_buf; + + if (map->cache_type == REGCACHE_NONE) { + map->cache_bypass = true; + return 0; + } + + for (i = 0; i < ARRAY_SIZE(cache_types); i++) + if (cache_types[i]->type == map->cache_type) + break; + + if (i == ARRAY_SIZE(cache_types)) { + dev_err(map->dev, "Could not match compress type: %d\n", + map->cache_type); + return -EINVAL; + } + + map->cache = NULL; + map->cache_ops = cache_types[i]; + + if (!map->cache_ops->read || + !map->cache_ops->write || + !map->cache_ops->name) + return -EINVAL; + + /* We still need to ensure that the reg_defaults + * won't vanish from under us. We'll need to make + * a copy of it. + */ + if (map->reg_defaults) { + if (!map->num_reg_defaults) + return -EINVAL; + tmp_buf = kmemdup(map->reg_defaults, map->num_reg_defaults * + sizeof(struct reg_default), GFP_KERNEL); + if (!tmp_buf) + return -ENOMEM; + map->reg_defaults = tmp_buf; + } else if (map->num_reg_defaults_raw) { + /* Some devices such as PMICs don't have cache defaults, + * we cope with this by reading back the HW registers and + * crafting the cache defaults by hand. + */ + ret = regcache_hw_init(map); + if (ret < 0) + return ret; + } + + if (!map->max_register) + map->max_register = map->num_reg_defaults_raw; + + if (map->cache_ops->init) { + dev_dbg(map->dev, "Initializing %s cache\n", + map->cache_ops->name); + return map->cache_ops->init(map); + } + return 0; +} + +void regcache_exit(struct regmap *map) +{ + if (map->cache_type == REGCACHE_NONE) + return; + + BUG_ON(!map->cache_ops); + + kfree(map->reg_defaults); + if (map->cache_free) + kfree(map->reg_defaults_raw); + + if (map->cache_ops->exit) { + dev_dbg(map->dev, "Destroying %s cache\n", + map->cache_ops->name); + map->cache_ops->exit(map); + } +} + +/** + * regcache_read: Fetch the value of a given register from the cache. + * + * @map: map to configure. + * @reg: The register index. + * @value: The value to be returned. + * + * Return a negative value on failure, 0 on success. + */ +int regcache_read(struct regmap *map, + unsigned int reg, unsigned int *value) +{ + if (map->cache_type == REGCACHE_NONE) + return -ENOSYS; + + BUG_ON(!map->cache_ops); + + if (!regmap_readable(map, reg)) + return -EIO; + + if (!regmap_volatile(map, reg)) + return map->cache_ops->read(map, reg, value); + + return -EINVAL; +} +EXPORT_SYMBOL_GPL(regcache_read); + +/** + * regcache_write: Set the value of a given register in the cache. + * + * @map: map to configure. + * @reg: The register index. + * @value: The new register value. + * + * Return a negative value on failure, 0 on success. + */ +int regcache_write(struct regmap *map, + unsigned int reg, unsigned int value) +{ + if (map->cache_type == REGCACHE_NONE) + return 0; + + BUG_ON(!map->cache_ops); + + if (!regmap_writeable(map, reg)) + return -EIO; + + if (!regmap_volatile(map, reg)) + return map->cache_ops->write(map, reg, value); + + return 0; +} +EXPORT_SYMBOL_GPL(regcache_write); + +/** + * regcache_sync: Sync the register cache with the hardware. + * + * @map: map to configure. + * + * Any registers that should not be synced should be marked as + * volatile. In general drivers can choose not to use the provided + * syncing functionality if they so require. + * + * Return a negative value on failure, 0 on success. + */ +int regcache_sync(struct regmap *map) +{ + int ret = 0; + unsigned int val; + unsigned int i; + const char *name; + unsigned int bypass; + + BUG_ON(!map->cache_ops); + + mutex_lock(&map->lock); + /* Remember the initial bypass state */ + bypass = map->cache_bypass; + dev_dbg(map->dev, "Syncing %s cache\n", + map->cache_ops->name); + name = map->cache_ops->name; + trace_regcache_sync(map->dev, name, "start"); + if (map->cache_ops->sync) { + ret = map->cache_ops->sync(map); + } else { + for (i = 0; i < map->num_reg_defaults; i++) { + ret = regcache_read(map, i, &val); + if (ret < 0) + goto out; + map->cache_bypass = 1; + ret = _regmap_write(map, i, val); + map->cache_bypass = 0; + if (ret < 0) + goto out; + dev_dbg(map->dev, "Synced register %#x, value %#x\n", + map->reg_defaults[i].reg, + map->reg_defaults[i].def); + } + + } +out: + trace_regcache_sync(map->dev, name, "stop"); + /* Restore the bypass state */ + map->cache_bypass = bypass; + mutex_unlock(&map->lock); + + return ret; +} +EXPORT_SYMBOL_GPL(regcache_sync); + +/** + * regcache_cache_only: Put a register map into cache only mode + * + * @map: map to configure + * @cache_only: flag if changes should be written to the hardware + * + * When a register map is marked as cache only writes to the register + * map API will only update the register cache, they will not cause + * any hardware changes. This is useful for allowing portions of + * drivers to act as though the device were functioning as normal when + * it is disabled for power saving reasons. + */ +void regcache_cache_only(struct regmap *map, bool enable) +{ + mutex_lock(&map->lock); + WARN_ON(map->cache_bypass && enable); + map->cache_only = enable; + mutex_unlock(&map->lock); +} +EXPORT_SYMBOL_GPL(regcache_cache_only); + +/** + * regcache_cache_bypass: Put a register map into cache bypass mode + * + * @map: map to configure + * @cache_bypass: flag if changes should not be written to the hardware + * + * When a register map is marked with the cache bypass option, writes + * to the register map API will only update the hardware and not the + * the cache directly. This is useful when syncing the cache back to + * the hardware. + */ +void regcache_cache_bypass(struct regmap *map, bool enable) +{ + mutex_lock(&map->lock); + WARN_ON(map->cache_only && enable); + map->cache_bypass = enable; + mutex_unlock(&map->lock); +} +EXPORT_SYMBOL_GPL(regcache_cache_bypass); + +bool regcache_set_val(void *base, unsigned int idx, + unsigned int val, unsigned int word_size) +{ + switch (word_size) { + case 1: { + u8 *cache = base; + if (cache[idx] == val) + return true; + cache[idx] = val; + break; + } + case 2: { + u16 *cache = base; + if (cache[idx] == val) + return true; + cache[idx] = val; + break; + } + default: + BUG(); + } + /* unreachable */ + return false; +} + +unsigned int regcache_get_val(const void *base, unsigned int idx, + unsigned int word_size) +{ + if (!base) + return -EINVAL; + + switch (word_size) { + case 1: { + const u8 *cache = base; + return cache[idx]; + } + case 2: { + const u16 *cache = base; + return cache[idx]; + } + default: + BUG(); + } + /* unreachable */ + return -1; +} + +static int regcache_default_cmp(const void *a, const void *b) +{ + const struct reg_default *_a = a; + const struct reg_default *_b = b; + + return _a->reg - _b->reg; +} + +int regcache_lookup_reg(struct regmap *map, unsigned int reg) +{ + struct reg_default key; + struct reg_default *r; + + key.reg = reg; + key.def = 0; + + r = bsearch(&key, map->reg_defaults, map->num_reg_defaults, + sizeof(struct reg_default), regcache_default_cmp); + + if (r) + return r - map->reg_defaults; + else + return -ENOENT; +} + +int regcache_insert_reg(struct regmap *map, unsigned int reg, + unsigned int val) +{ + void *tmp; + + tmp = krealloc(map->reg_defaults, + (map->num_reg_defaults + 1) * sizeof(struct reg_default), + GFP_KERNEL); + if (!tmp) + return -ENOMEM; + map->reg_defaults = tmp; + map->num_reg_defaults++; + map->reg_defaults[map->num_reg_defaults - 1].reg = reg; + map->reg_defaults[map->num_reg_defaults - 1].def = val; + sort(map->reg_defaults, map->num_reg_defaults, + sizeof(struct reg_default), regcache_default_cmp, NULL); + return 0; +} |