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linux-next/drivers/base/regmap/regcache.c

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/*
* 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[] = {
&regcache_rbtree_ops,
&regcache_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) {
ret = -ENOMEM;
goto err_free;
}
/* 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;
err_free:
if (map->cache_free)
kfree(map->reg_defaults_raw);
return ret;
}
int regcache_init(struct regmap *map, const struct regmap_config *config)
{
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->num_reg_defaults = config->num_reg_defaults;
map->num_reg_defaults_raw = config->num_reg_defaults_raw;
map->reg_defaults_raw = config->reg_defaults_raw;
map->cache_word_size = DIV_ROUND_UP(config->val_bits, 8);
map->cache_size_raw = map->cache_word_size * config->num_reg_defaults_raw;
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 (config->reg_defaults) {
if (!map->num_reg_defaults)
return -EINVAL;
tmp_buf = kmemdup(config->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);
ret = map->cache_ops->init(map);
if (ret)
goto err_free;
}
return 0;
err_free:
kfree(map->reg_defaults);
if (map->cache_free)
kfree(map->reg_defaults_raw);
return ret;
}
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)
{
int ret;
if (map->cache_type == REGCACHE_NONE)
return -ENOSYS;
BUG_ON(!map->cache_ops);
if (!regmap_volatile(map, reg)) {
ret = map->cache_ops->read(map, reg, value);
if (ret == 0)
trace_regmap_reg_read_cache(map->dev, reg, *value);
return ret;
}
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_dirty)
goto out;
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_mark_dirty: Mark the register cache as dirty
*
* @map: map to mark
*
* Mark the register cache as dirty, for example due to the device
* having been powered down for suspend. If the cache is not marked
* as dirty then the cache sync will be suppressed.
*/
void regcache_mark_dirty(struct regmap *map)
{
mutex_lock(&map->lock);
map->cache_dirty = true;
mutex_unlock(&map->lock);
}
EXPORT_SYMBOL_GPL(regcache_mark_dirty);
/**
* 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;
}