blob: 362e043e26d86792ed44793f251ae2428c5bf426 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0
//
// Register cache access API
//
// Copyright 2011 Wolfson Microelectronics plc
//
// Author: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
#include <linux/bsearch.h>
#include <linux/device.h>
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/sort.h>
#include "trace.h"
#include "internal.h"
static const struct regcache_ops *cache_types[] = {
&regcache_rbtree_ops,
#if IS_ENABLED(CONFIG_REGCACHE_COMPRESSED)
&regcache_lzo_ops,
#endif
&regcache_flat_ops,
};
static int regcache_hw_init(struct regmap *map)
{
int i, j;
int ret;
int count;
unsigned int reg, val;
void *tmp_buf;
if (!map->num_reg_defaults_raw)
return -EINVAL;
/* calculate the size of reg_defaults */
for (count = 0, i = 0; i < map->num_reg_defaults_raw; i++)
if (regmap_readable(map, i * map->reg_stride) &&
!regmap_volatile(map, i * map->reg_stride))
count++;
/* all registers are unreadable or volatile, so just bypass */
if (!count) {
map->cache_bypass = true;
return 0;
}
map->num_reg_defaults = count;
map->reg_defaults = kmalloc_array(count, sizeof(struct reg_default),
GFP_KERNEL);
if (!map->reg_defaults)
return -ENOMEM;
if (!map->reg_defaults_raw) {
bool cache_bypass = map->cache_bypass;
dev_warn(map->dev, "No cache defaults, reading back from HW\n");
/* Bypass the cache access till data read from HW */
map->cache_bypass = true;
tmp_buf = kmalloc(map->cache_size_raw, GFP_KERNEL);
if (!tmp_buf) {
ret = -ENOMEM;
goto err_free;
}
ret = regmap_raw_read(map, 0, tmp_buf,
map->cache_size_raw);
map->cache_bypass = cache_bypass;
if (ret == 0) {
map->reg_defaults_raw = tmp_buf;
map->cache_free = true;
} else {
kfree(tmp_buf);
}
}
/* fill the reg_defaults */
for (i = 0, j = 0; i < map->num_reg_defaults_raw; i++) {
reg = i * map->reg_stride;
if (!regmap_readable(map, reg))
continue;
if (regmap_volatile(map, reg))
continue;
if (map->reg_defaults_raw) {
val = regcache_get_val(map, map->reg_defaults_raw, i);
} else {
bool cache_bypass = map->cache_bypass;
map->cache_bypass = true;
ret = regmap_read(map, reg, &val);
map->cache_bypass = cache_bypass;
if (ret != 0) {
dev_err(map->dev, "Failed to read %d: %d\n",
reg, ret);
goto err_free;
}
}
map->reg_defaults[j].reg = reg;
map->reg_defaults[j].def = val;
j++;
}
return 0;
err_free:
kfree(map->reg_defaults);
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) {
if (config->reg_defaults || config->num_reg_defaults_raw)
dev_warn(map->dev,
"No cache used with register defaults set!\n");
map->cache_bypass = true;
return 0;
}
if (config->reg_defaults && !config->num_reg_defaults) {
dev_err(map->dev,
"Register defaults are set without the number!\n");
return -EINVAL;
}
if (config->num_reg_defaults && !config->reg_defaults) {
dev_err(map->dev,
"Register defaults number are set without the reg!\n");
return -EINVAL;
}
for (i = 0; i < config->num_reg_defaults; i++)
if (config->reg_defaults[i].reg % map->reg_stride)
return -EINVAL;
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) {
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->cache_bypass)
return 0;
}
if (!map->max_register && map->num_reg_defaults_raw)
map->max_register = (map->num_reg_defaults_raw - 1) * map->reg_stride;
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, reg, *value);
return ret;
}
return -EINVAL;
}
/**
* 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_volatile(map, reg))
return map->cache_ops->write(map, reg, value);
return 0;
}
static bool regcache_reg_needs_sync(struct regmap *map, unsigned int reg,
unsigned int val)
{
int ret;
/* If we don't know the chip just got reset, then sync everything. */
if (!map->no_sync_defaults)
return true;
/* Is this the hardware default? If so skip. */
ret = regcache_lookup_reg(map, reg);
if (ret >= 0 && val == map->reg_defaults[ret].def)
return false;
return true;
}
static int regcache_default_sync(struct regmap *map, unsigned int min,
unsigned int max)
{
unsigned int reg;
for (reg = min; reg <= max; reg += map->reg_stride) {
unsigned int val;
int ret;
if (regmap_volatile(map, reg) ||
!regmap_writeable(map, reg))
continue;
ret = regcache_read(map, reg, &val);
if (ret)
return ret;
if (!regcache_reg_needs_sync(map, reg, val))
continue;
map->cache_bypass = true;
ret = _regmap_write(map, reg, val);
map->cache_bypass = false;
if (ret) {
dev_err(map->dev, "Unable to sync register %#x. %d\n",
reg, ret);
return ret;
}
dev_dbg(map->dev, "Synced register %#x, value %#x\n", reg, val);
}
return 0;
}
/**
* 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 i;
const char *name;
bool bypass;
BUG_ON(!map->cache_ops);
map->lock(map->lock_arg);
/* 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, name, "start");
if (!map->cache_dirty)
goto out;
map->async = true;
/* Apply any patch first */
map->cache_bypass = true;
for (i = 0; i < map->patch_regs; i++) {
ret = _regmap_write(map, map->patch[i].reg, map->patch[i].def);
if (ret != 0) {
dev_err(map->dev, "Failed to write %x = %x: %d\n",
map->patch[i].reg, map->patch[i].def, ret);
goto out;
}
}
map->cache_bypass = false;
if (map->cache_ops->sync)
ret = map->cache_ops->sync(map, 0, map->max_register);
else
ret = regcache_default_sync(map, 0, map->max_register);
if (ret == 0)
map->cache_dirty = false;
out:
/* Restore the bypass state */
map->async = false;
map->cache_bypass = bypass;
map->no_sync_defaults = false;
map->unlock(map->lock_arg);
regmap_async_complete(map);
trace_regcache_sync(map, name, "stop");
return ret;
}
EXPORT_SYMBOL_GPL(regcache_sync);
/**
* regcache_sync_region - Sync part of the register cache with the hardware.
*
* @map: map to sync.
* @min: first register to sync
* @max: last register to sync
*
* Write all non-default register values in the specified region to
* the hardware.
*
* Return a negative value on failure, 0 on success.
*/
int regcache_sync_region(struct regmap *map, unsigned int min,
unsigned int max)
{
int ret = 0;
const char *name;
bool bypass;
BUG_ON(!map->cache_ops);
map->lock(map->lock_arg);
/* Remember the initial bypass state */
bypass = map->cache_bypass;
name = map->cache_ops->name;
dev_dbg(map->dev, "Syncing %s cache from %d-%d\n", name, min, max);
trace_regcache_sync(map, name, "start region");
if (!map->cache_dirty)
goto out;
map->async = true;
if (map->cache_ops->sync)
ret = map->cache_ops->sync(map, min, max);
else
ret = regcache_default_sync(map, min, max);
out:
/* Restore the bypass state */
map->cache_bypass = bypass;
map->async = false;
map->no_sync_defaults = false;
map->unlock(map->lock_arg);
regmap_async_complete(map);
trace_regcache_sync(map, name, "stop region");
return ret;
}
EXPORT_SYMBOL_GPL(regcache_sync_region);
/**
* regcache_drop_region - Discard part of the register cache
*
* @map: map to operate on
* @min: first register to discard
* @max: last register to discard
*
* Discard part of the register cache.
*
* Return a negative value on failure, 0 on success.
*/
int regcache_drop_region(struct regmap *map, unsigned int min,
unsigned int max)
{
int ret = 0;
if (!map->cache_ops || !map->cache_ops->drop)
return -EINVAL;
map->lock(map->lock_arg);
trace_regcache_drop_region(map, min, max);
ret = map->cache_ops->drop(map, min, max);
map->unlock(map->lock_arg);
return ret;
}
EXPORT_SYMBOL_GPL(regcache_drop_region);
/**
* regcache_cache_only - Put a register map into cache only mode
*
* @map: map to configure
* @enable: 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)
{
map->lock(map->lock_arg);
WARN_ON(map->cache_type != REGCACHE_NONE &&
map->cache_bypass && enable);
map->cache_only = enable;
trace_regmap_cache_only(map, enable);
map->unlock(map->lock_arg);
}
EXPORT_SYMBOL_GPL(regcache_cache_only);
/**
* regcache_mark_dirty - Indicate that HW registers were reset to default values
*
* @map: map to mark
*
* Inform regcache that the device has been powered down or reset, so that
* on resume, regcache_sync() knows to write out all non-default values
* stored in the cache.
*
* If this function is not called, regcache_sync() will assume that
* the hardware state still matches the cache state, modulo any writes that
* happened when cache_only was true.
*/
void regcache_mark_dirty(struct regmap *map)
{
map->lock(map->lock_arg);
map->cache_dirty = true;
map->no_sync_defaults = true;
map->unlock(map->lock_arg);
}
EXPORT_SYMBOL_GPL(regcache_mark_dirty);
/**
* regcache_cache_bypass - Put a register map into cache bypass mode
*
* @map: map to configure
* @enable: flag if changes should not be written to the cache
*
* 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 cache directly. This is useful when syncing the cache back to
* the hardware.
*/
void regcache_cache_bypass(struct regmap *map, bool enable)
{
map->lock(map->lock_arg);
WARN_ON(map->cache_only && enable);
map->cache_bypass = enable;
trace_regmap_cache_bypass(map, enable);
map->unlock(map->lock_arg);
}
EXPORT_SYMBOL_GPL(regcache_cache_bypass);
bool regcache_set_val(struct regmap *map, void *base, unsigned int idx,
unsigned int val)
{
if (regcache_get_val(map, base, idx) == val)
return true;
/* Use device native format if possible */
if (map->format.format_val) {
map->format.format_val(base + (map->cache_word_size * idx),
val, 0);
return false;
}
switch (map->cache_word_size) {
case 1: {
u8 *cache = base;
cache[idx] = val;
break;
}
case 2: {
u16 *cache = base;
cache[idx] = val;
break;
}
case 4: {
u32 *cache = base;
cache[idx] = val;
break;
}
#ifdef CONFIG_64BIT
case 8: {
u64 *cache = base;
cache[idx] = val;
break;
}
#endif
default:
BUG();
}
return false;
}
unsigned int regcache_get_val(struct regmap *map, const void *base,
unsigned int idx)
{
if (!base)
return -EINVAL;
/* Use device native format if possible */
if (map->format.parse_val)
return map->format.parse_val(regcache_get_val_addr(map, base,
idx));
switch (map->cache_word_size) {
case 1: {
const u8 *cache = base;
return cache[idx];
}
case 2: {
const u16 *cache = base;
return cache[idx];
}
case 4: {
const u32 *cache = base;
return cache[idx];
}
#ifdef CONFIG_64BIT
case 8: {
const u64 *cache = base;
return cache[idx];
}
#endif
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;
}
static bool regcache_reg_present(unsigned long *cache_present, unsigned int idx)
{
if (!cache_present)
return true;
return test_bit(idx, cache_present);
}
static int regcache_sync_block_single(struct regmap *map, void *block,
unsigned long *cache_present,
unsigned int block_base,
unsigned int start, unsigned int end)
{
unsigned int i, regtmp, val;
int ret;
for (i = start; i < end; i++) {
regtmp = block_base + (i * map->reg_stride);
if (!regcache_reg_present(cache_present, i) ||
!regmap_writeable(map, regtmp))
continue;
val = regcache_get_val(map, block, i);
if (!regcache_reg_needs_sync(map, regtmp, val))
continue;
map->cache_bypass = true;
ret = _regmap_write(map, regtmp, val);
map->cache_bypass = false;
if (ret != 0) {
dev_err(map->dev, "Unable to sync register %#x. %d\n",
regtmp, ret);
return ret;
}
dev_dbg(map->dev, "Synced register %#x, value %#x\n",
regtmp, val);
}
return 0;
}
static int regcache_sync_block_raw_flush(struct regmap *map, const void **data,
unsigned int base, unsigned int cur)
{
size_t val_bytes = map->format.val_bytes;
int ret, count;
if (*data == NULL)
return 0;
count = (cur - base) / map->reg_stride;
dev_dbg(map->dev, "Writing %zu bytes for %d registers from 0x%x-0x%x\n",
count * val_bytes, count, base, cur - map->reg_stride);
map->cache_bypass = true;
ret = _regmap_raw_write(map, base, *data, count * val_bytes, false);
if (ret)
dev_err(map->dev, "Unable to sync registers %#x-%#x. %d\n",
base, cur - map->reg_stride, ret);
map->cache_bypass = false;
*data = NULL;
return ret;
}
static int regcache_sync_block_raw(struct regmap *map, void *block,
unsigned long *cache_present,
unsigned int block_base, unsigned int start,
unsigned int end)
{
unsigned int i, val;
unsigned int regtmp = 0;
unsigned int base = 0;
const void *data = NULL;
int ret;
for (i = start; i < end; i++) {
regtmp = block_base + (i * map->reg_stride);
if (!regcache_reg_present(cache_present, i) ||
!regmap_writeable(map, regtmp)) {
ret = regcache_sync_block_raw_flush(map, &data,
base, regtmp);
if (ret != 0)
return ret;
continue;
}
val = regcache_get_val(map, block, i);
if (!regcache_reg_needs_sync(map, regtmp, val)) {
ret = regcache_sync_block_raw_flush(map, &data,
base, regtmp);
if (ret != 0)
return ret;
continue;
}
if (!data) {
data = regcache_get_val_addr(map, block, i);
base = regtmp;
}
}
return regcache_sync_block_raw_flush(map, &data, base, regtmp +
map->reg_stride);
}
int regcache_sync_block(struct regmap *map, void *block,
unsigned long *cache_present,
unsigned int block_base, unsigned int start,
unsigned int end)
{
if (regmap_can_raw_write(map) && !map->use_single_write)
return regcache_sync_block_raw(map, block, cache_present,
block_base, start, end);
else
return regcache_sync_block_single(map, block, cache_present,
block_base, start, end);
}