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linux-next/sound/soc/soc-cache.c

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/*
* soc-cache.c -- ASoC register cache helpers
*
* Copyright 2009 Wolfson Microelectronics PLC.
*
* Author: Mark Brown <broonie@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 as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*/
#include <linux/i2c.h>
#include <linux/spi/spi.h>
#include <sound/soc.h>
#include <linux/bitmap.h>
ASoC: soc-cache: Add support for rbtree based register caching This patch adds support for rbtree compression when storing the register cache. It does this by not adding any uninitialized registers (those whose value is 0). If any of those registers is written with a nonzero value they get added into the rbtree. Consider a sample device with a large sparse register map. The register indices are between [0, 0x31ff]. An array of 12800 registers is thus created each of which is 2 bytes. This results in a 25kB region. This array normally lives outside soc-core, normally in the driver itself. The original soc-core code would kmemdup this region resulting in 50kB total memory. When using the rbtree compression technique and __devinitconst on the original array the figures are as follows. For this typical device, you might have 100 initialized registers, that is registers that are nonzero by default. We build an rbtree with 100 nodes, each of which is 24 bytes. This results in ~2kB of memory. Assuming that the target arch can freeup the memory used by the initial __devinitconst array, we end up using about ~2kB bytes of actual memory. The memory footprint will increase as uninitialized registers get written and thus new nodes created in the rbtree. In practice, most of those registers are never changed. If the target arch can't freeup the __devinitconst array, we end up using a total of ~27kB. The difference between the rbtree and the LZO caching techniques, is that if using the LZO technique the size of the cache will increase slower as more uninitialized registers get changed. Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com> Acked-by: Liam Girdwood <lrg@slimlogic.co.uk> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2010-11-11 18:04:59 +08:00
#include <linux/rbtree.h>
#include <linux/export.h>
#include <trace/events/asoc.h>
static bool snd_soc_set_cache_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();
}
return false;
}
static unsigned int snd_soc_get_cache_val(const void *base, unsigned int idx,
unsigned int word_size)
{
if (!base)
return -1;
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 snd_soc_flat_cache_sync(struct snd_soc_codec *codec)
{
int i;
int ret;
const struct snd_soc_codec_driver *codec_drv;
unsigned int val;
codec_drv = codec->driver;
for (i = 0; i < codec_drv->reg_cache_size; ++i) {
ret = snd_soc_cache_read(codec, i, &val);
if (ret)
return ret;
if (codec->reg_def_copy)
if (snd_soc_get_cache_val(codec->reg_def_copy,
i, codec_drv->reg_word_size) == val)
continue;
WARN_ON(!snd_soc_codec_writable_register(codec, i));
ret = snd_soc_write(codec, i, val);
if (ret)
return ret;
dev_dbg(codec->dev, "Synced register %#x, value = %#x\n",
i, val);
}
return 0;
}
static int snd_soc_flat_cache_write(struct snd_soc_codec *codec,
unsigned int reg, unsigned int value)
{
snd_soc_set_cache_val(codec->reg_cache, reg, value,
codec->driver->reg_word_size);
return 0;
}
static int snd_soc_flat_cache_read(struct snd_soc_codec *codec,
unsigned int reg, unsigned int *value)
{
*value = snd_soc_get_cache_val(codec->reg_cache, reg,
codec->driver->reg_word_size);
return 0;
}
static int snd_soc_flat_cache_exit(struct snd_soc_codec *codec)
{
if (!codec->reg_cache)
return 0;
kfree(codec->reg_cache);
codec->reg_cache = NULL;
return 0;
}
static int snd_soc_flat_cache_init(struct snd_soc_codec *codec)
{
if (codec->reg_def_copy)
codec->reg_cache = kmemdup(codec->reg_def_copy,
codec->reg_size, GFP_KERNEL);
else
codec->reg_cache = kzalloc(codec->reg_size, GFP_KERNEL);
if (!codec->reg_cache)
return -ENOMEM;
return 0;
}
/* an array of all supported compression types */
static const struct snd_soc_cache_ops cache_types[] = {
/* Flat *must* be the first entry for fallback */
{
.id = SND_SOC_FLAT_COMPRESSION,
.name = "flat",
.init = snd_soc_flat_cache_init,
.exit = snd_soc_flat_cache_exit,
.read = snd_soc_flat_cache_read,
.write = snd_soc_flat_cache_write,
.sync = snd_soc_flat_cache_sync
},
};
int snd_soc_cache_init(struct snd_soc_codec *codec)
{
int i;
for (i = 0; i < ARRAY_SIZE(cache_types); ++i)
if (cache_types[i].id == codec->compress_type)
break;
/* Fall back to flat compression */
if (i == ARRAY_SIZE(cache_types)) {
dev_warn(codec->dev, "Could not match compress type: %d\n",
codec->compress_type);
i = 0;
}
mutex_init(&codec->cache_rw_mutex);
codec->cache_ops = &cache_types[i];
if (codec->cache_ops->init) {
if (codec->cache_ops->name)
dev_dbg(codec->dev, "Initializing %s cache for %s codec\n",
codec->cache_ops->name, codec->name);
return codec->cache_ops->init(codec);
}
return -ENOSYS;
}
/*
* NOTE: keep in mind that this function might be called
* multiple times.
*/
int snd_soc_cache_exit(struct snd_soc_codec *codec)
{
if (codec->cache_ops && codec->cache_ops->exit) {
if (codec->cache_ops->name)
dev_dbg(codec->dev, "Destroying %s cache for %s codec\n",
codec->cache_ops->name, codec->name);
return codec->cache_ops->exit(codec);
}
return -ENOSYS;
}
/**
* snd_soc_cache_read: Fetch the value of a given register from the cache.
*
* @codec: CODEC to configure.
* @reg: The register index.
* @value: The value to be returned.
*/
int snd_soc_cache_read(struct snd_soc_codec *codec,
unsigned int reg, unsigned int *value)
{
int ret;
mutex_lock(&codec->cache_rw_mutex);
if (value && codec->cache_ops && codec->cache_ops->read) {
ret = codec->cache_ops->read(codec, reg, value);
mutex_unlock(&codec->cache_rw_mutex);
return ret;
}
mutex_unlock(&codec->cache_rw_mutex);
return -ENOSYS;
}
EXPORT_SYMBOL_GPL(snd_soc_cache_read);
/**
* snd_soc_cache_write: Set the value of a given register in the cache.
*
* @codec: CODEC to configure.
* @reg: The register index.
* @value: The new register value.
*/
int snd_soc_cache_write(struct snd_soc_codec *codec,
unsigned int reg, unsigned int value)
{
int ret;
mutex_lock(&codec->cache_rw_mutex);
if (codec->cache_ops && codec->cache_ops->write) {
ret = codec->cache_ops->write(codec, reg, value);
mutex_unlock(&codec->cache_rw_mutex);
return ret;
}
mutex_unlock(&codec->cache_rw_mutex);
return -ENOSYS;
}
EXPORT_SYMBOL_GPL(snd_soc_cache_write);
/**
* snd_soc_cache_sync: Sync the register cache with the hardware.
*
* @codec: CODEC 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.
*/
int snd_soc_cache_sync(struct snd_soc_codec *codec)
{
int ret;
const char *name;
if (!codec->cache_sync) {
return 0;
}
if (!codec->cache_ops || !codec->cache_ops->sync)
return -ENOSYS;
if (codec->cache_ops->name)
name = codec->cache_ops->name;
else
name = "unknown";
if (codec->cache_ops->name)
dev_dbg(codec->dev, "Syncing %s cache for %s codec\n",
codec->cache_ops->name, codec->name);
trace_snd_soc_cache_sync(codec, name, "start");
ret = codec->cache_ops->sync(codec);
if (!ret)
codec->cache_sync = 0;
trace_snd_soc_cache_sync(codec, name, "end");
return ret;
}
EXPORT_SYMBOL_GPL(snd_soc_cache_sync);
static int snd_soc_get_reg_access_index(struct snd_soc_codec *codec,
unsigned int reg)
{
const struct snd_soc_codec_driver *codec_drv;
unsigned int min, max, index;
codec_drv = codec->driver;
min = 0;
max = codec_drv->reg_access_size - 1;
do {
index = (min + max) / 2;
if (codec_drv->reg_access_default[index].reg == reg)
return index;
if (codec_drv->reg_access_default[index].reg < reg)
min = index + 1;
else
max = index;
} while (min <= max);
return -1;
}
int snd_soc_default_volatile_register(struct snd_soc_codec *codec,
unsigned int reg)
{
int index;
if (reg >= codec->driver->reg_cache_size)
return 1;
index = snd_soc_get_reg_access_index(codec, reg);
if (index < 0)
return 0;
return codec->driver->reg_access_default[index].vol;
}
EXPORT_SYMBOL_GPL(snd_soc_default_volatile_register);
int snd_soc_default_readable_register(struct snd_soc_codec *codec,
unsigned int reg)
{
int index;
if (reg >= codec->driver->reg_cache_size)
return 1;
index = snd_soc_get_reg_access_index(codec, reg);
if (index < 0)
return 0;
return codec->driver->reg_access_default[index].read;
}
EXPORT_SYMBOL_GPL(snd_soc_default_readable_register);
int snd_soc_default_writable_register(struct snd_soc_codec *codec,
unsigned int reg)
{
int index;
if (reg >= codec->driver->reg_cache_size)
return 1;
index = snd_soc_get_reg_access_index(codec, reg);
if (index < 0)
return 0;
return codec->driver->reg_access_default[index].write;
}
EXPORT_SYMBOL_GPL(snd_soc_default_writable_register);