soc-cache.c

/*
 * 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>
#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);