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

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/*
* Register cache access API - LZO caching support
*
* 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/device.h>
#include <linux/lzo.h>
#include <linux/slab.h>
#include "internal.h"
static int regcache_lzo_exit(struct regmap *map);
struct regcache_lzo_ctx {
void *wmem;
void *dst;
const void *src;
size_t src_len;
size_t dst_len;
size_t decompressed_size;
unsigned long *sync_bmp;
int sync_bmp_nbits;
};
#define LZO_BLOCK_NUM 8
static int regcache_lzo_block_count(struct regmap *map)
{
return LZO_BLOCK_NUM;
}
static int regcache_lzo_prepare(struct regcache_lzo_ctx *lzo_ctx)
{
lzo_ctx->wmem = kmalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL);
if (!lzo_ctx->wmem)
return -ENOMEM;
return 0;
}
static int regcache_lzo_compress(struct regcache_lzo_ctx *lzo_ctx)
{
size_t compress_size;
int ret;
ret = lzo1x_1_compress(lzo_ctx->src, lzo_ctx->src_len,
lzo_ctx->dst, &compress_size, lzo_ctx->wmem);
if (ret != LZO_E_OK || compress_size > lzo_ctx->dst_len)
return -EINVAL;
lzo_ctx->dst_len = compress_size;
return 0;
}
static int regcache_lzo_decompress(struct regcache_lzo_ctx *lzo_ctx)
{
size_t dst_len;
int ret;
dst_len = lzo_ctx->dst_len;
ret = lzo1x_decompress_safe(lzo_ctx->src, lzo_ctx->src_len,
lzo_ctx->dst, &dst_len);
if (ret != LZO_E_OK || dst_len != lzo_ctx->dst_len)
return -EINVAL;
return 0;
}
static int regcache_lzo_compress_cache_block(struct regmap *map,
struct regcache_lzo_ctx *lzo_ctx)
{
int ret;
lzo_ctx->dst_len = lzo1x_worst_compress(PAGE_SIZE);
lzo_ctx->dst = kmalloc(lzo_ctx->dst_len, GFP_KERNEL);
if (!lzo_ctx->dst) {
lzo_ctx->dst_len = 0;
return -ENOMEM;
}
ret = regcache_lzo_compress(lzo_ctx);
if (ret < 0)
return ret;
return 0;
}
static int regcache_lzo_decompress_cache_block(struct regmap *map,
struct regcache_lzo_ctx *lzo_ctx)
{
int ret;
lzo_ctx->dst_len = lzo_ctx->decompressed_size;
lzo_ctx->dst = kmalloc(lzo_ctx->dst_len, GFP_KERNEL);
if (!lzo_ctx->dst) {
lzo_ctx->dst_len = 0;
return -ENOMEM;
}
ret = regcache_lzo_decompress(lzo_ctx);
if (ret < 0)
return ret;
return 0;
}
static inline int regcache_lzo_get_blkindex(struct regmap *map,
unsigned int reg)
{
return ((reg / map->reg_stride) * map->cache_word_size) /
DIV_ROUND_UP(map->cache_size_raw,
regcache_lzo_block_count(map));
}
static inline int regcache_lzo_get_blkpos(struct regmap *map,
unsigned int reg)
{
return (reg / map->reg_stride) %
(DIV_ROUND_UP(map->cache_size_raw,
regcache_lzo_block_count(map)) /
map->cache_word_size);
}
static inline int regcache_lzo_get_blksize(struct regmap *map)
{
return DIV_ROUND_UP(map->cache_size_raw,
regcache_lzo_block_count(map));
}
static int regcache_lzo_init(struct regmap *map)
{
struct regcache_lzo_ctx **lzo_blocks;
size_t bmp_size;
int ret, i, blksize, blkcount;
const char *p, *end;
unsigned long *sync_bmp;
ret = 0;
blkcount = regcache_lzo_block_count(map);
map->cache = kcalloc(blkcount, sizeof(*lzo_blocks),
GFP_KERNEL);
if (!map->cache)
return -ENOMEM;
lzo_blocks = map->cache;
/*
* allocate a bitmap to be used when syncing the cache with
* the hardware. Each time a register is modified, the corresponding
* bit is set in the bitmap, so we know that we have to sync
* that register.
*/
bmp_size = map->num_reg_defaults_raw;
sync_bmp = kmalloc_array(BITS_TO_LONGS(bmp_size), sizeof(long),
GFP_KERNEL);
if (!sync_bmp) {
ret = -ENOMEM;
goto err;
}
bitmap_zero(sync_bmp, bmp_size);
/* allocate the lzo blocks and initialize them */
for (i = 0; i < blkcount; i++) {
lzo_blocks[i] = kzalloc(sizeof **lzo_blocks,
GFP_KERNEL);
if (!lzo_blocks[i]) {
kfree(sync_bmp);
ret = -ENOMEM;
goto err;
}
lzo_blocks[i]->sync_bmp = sync_bmp;
lzo_blocks[i]->sync_bmp_nbits = bmp_size;
/* alloc the working space for the compressed block */
ret = regcache_lzo_prepare(lzo_blocks[i]);
if (ret < 0)
goto err;
}
blksize = regcache_lzo_get_blksize(map);
p = map->reg_defaults_raw;
end = map->reg_defaults_raw + map->cache_size_raw;
/* compress the register map and fill the lzo blocks */
for (i = 0; i < blkcount; i++, p += blksize) {
lzo_blocks[i]->src = p;
if (p + blksize > end)
lzo_blocks[i]->src_len = end - p;
else
lzo_blocks[i]->src_len = blksize;
ret = regcache_lzo_compress_cache_block(map,
lzo_blocks[i]);
if (ret < 0)
goto err;
lzo_blocks[i]->decompressed_size =
lzo_blocks[i]->src_len;
}
return 0;
err:
regcache_lzo_exit(map);
return ret;
}
static int regcache_lzo_exit(struct regmap *map)
{
struct regcache_lzo_ctx **lzo_blocks;
int i, blkcount;
lzo_blocks = map->cache;
if (!lzo_blocks)
return 0;
blkcount = regcache_lzo_block_count(map);
/*
* the pointer to the bitmap used for syncing the cache
* is shared amongst all lzo_blocks. Ensure it is freed
* only once.
*/
if (lzo_blocks[0])
kfree(lzo_blocks[0]->sync_bmp);
for (i = 0; i < blkcount; i++) {
if (lzo_blocks[i]) {
kfree(lzo_blocks[i]->wmem);
kfree(lzo_blocks[i]->dst);
}
/* each lzo_block is a pointer returned by kmalloc or NULL */
kfree(lzo_blocks[i]);
}
kfree(lzo_blocks);
map->cache = NULL;
return 0;
}
static int regcache_lzo_read(struct regmap *map,
unsigned int reg, unsigned int *value)
{
struct regcache_lzo_ctx *lzo_block, **lzo_blocks;
int ret, blkindex, blkpos;
size_t blksize, tmp_dst_len;
void *tmp_dst;
/* index of the compressed lzo block */
blkindex = regcache_lzo_get_blkindex(map, reg);
/* register index within the decompressed block */
blkpos = regcache_lzo_get_blkpos(map, reg);
/* size of the compressed block */
blksize = regcache_lzo_get_blksize(map);
lzo_blocks = map->cache;
lzo_block = lzo_blocks[blkindex];
/* save the pointer and length of the compressed block */
tmp_dst = lzo_block->dst;
tmp_dst_len = lzo_block->dst_len;
/* prepare the source to be the compressed block */
lzo_block->src = lzo_block->dst;
lzo_block->src_len = lzo_block->dst_len;
/* decompress the block */
ret = regcache_lzo_decompress_cache_block(map, lzo_block);
if (ret >= 0)
/* fetch the value from the cache */
*value = regcache_get_val(map, lzo_block->dst, blkpos);
kfree(lzo_block->dst);
/* restore the pointer and length of the compressed block */
lzo_block->dst = tmp_dst;
lzo_block->dst_len = tmp_dst_len;
return ret;
}
static int regcache_lzo_write(struct regmap *map,
unsigned int reg, unsigned int value)
{
struct regcache_lzo_ctx *lzo_block, **lzo_blocks;
int ret, blkindex, blkpos;
size_t blksize, tmp_dst_len;
void *tmp_dst;
/* index of the compressed lzo block */
blkindex = regcache_lzo_get_blkindex(map, reg);
/* register index within the decompressed block */
blkpos = regcache_lzo_get_blkpos(map, reg);
/* size of the compressed block */
blksize = regcache_lzo_get_blksize(map);
lzo_blocks = map->cache;
lzo_block = lzo_blocks[blkindex];
/* save the pointer and length of the compressed block */
tmp_dst = lzo_block->dst;
tmp_dst_len = lzo_block->dst_len;
/* prepare the source to be the compressed block */
lzo_block->src = lzo_block->dst;
lzo_block->src_len = lzo_block->dst_len;
/* decompress the block */
ret = regcache_lzo_decompress_cache_block(map, lzo_block);
if (ret < 0) {
kfree(lzo_block->dst);
goto out;
}
/* write the new value to the cache */
if (regcache_set_val(map, lzo_block->dst, blkpos, value)) {
kfree(lzo_block->dst);
goto out;
}
/* prepare the source to be the decompressed block */
lzo_block->src = lzo_block->dst;
lzo_block->src_len = lzo_block->dst_len;
/* compress the block */
ret = regcache_lzo_compress_cache_block(map, lzo_block);
if (ret < 0) {
kfree(lzo_block->dst);
kfree(lzo_block->src);
goto out;
}
/* set the bit so we know we have to sync this register */
set_bit(reg / map->reg_stride, lzo_block->sync_bmp);
kfree(tmp_dst);
kfree(lzo_block->src);
return 0;
out:
lzo_block->dst = tmp_dst;
lzo_block->dst_len = tmp_dst_len;
return ret;
}
static int regcache_lzo_sync(struct regmap *map, unsigned int min,
unsigned int max)
{
struct regcache_lzo_ctx **lzo_blocks;
unsigned int val;
int i;
int ret;
lzo_blocks = map->cache;
i = min;
for_each_set_bit_from(i, lzo_blocks[0]->sync_bmp,
lzo_blocks[0]->sync_bmp_nbits) {
if (i > max)
continue;
ret = regcache_read(map, i, &val);
if (ret)
return ret;
/* Is this the hardware default? If so skip. */
ret = regcache_lookup_reg(map, i);
if (ret > 0 && val == map->reg_defaults[ret].def)
continue;
map->cache_bypass = true;
ret = _regmap_write(map, i, val);
map->cache_bypass = false;
if (ret)
return ret;
dev_dbg(map->dev, "Synced register %#x, value %#x\n",
i, val);
}
return 0;
}
struct regcache_ops regcache_lzo_ops = {
.type = REGCACHE_COMPRESSED,
.name = "lzo",
.init = regcache_lzo_init,
.exit = regcache_lzo_exit,
.read = regcache_lzo_read,
.write = regcache_lzo_write,
.sync = regcache_lzo_sync
};