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linux/drivers/base/regmap/regcache-lzo.c
Stephen Warren f01ee60fff regmap: implement register striding
regmap_config.reg_stride is introduced. All extant register addresses
are a multiple of this value. Users of serial-oriented regmap busses will
typically set this to 1. Users of the MMIO regmap bus will typically set
this based on the value size of their registers, in bytes, so 4 for a
32-bit register.

Throughout the regmap code, actual register addresses are used. Wherever
the register address is used to index some array of values, the address
is divided by the stride to determine the index, or vice-versa. Error-
checking is added to all entry-points for register address data to ensure
that register addresses actually satisfy the specified stride. The MMIO
bus ensures that the specified stride is large enough for the register
size.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2012-04-10 11:01:18 +01:00

381 lines
9.1 KiB
C

/*
* 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/slab.h>
#include <linux/device.h>
#include <linux/lzo.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 = kzalloc(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(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(lzo_block->dst, blkpos,
map->cache_word_size);
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(lzo_block->dst, blkpos, value,
map->cache_word_size)) {
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 = 1;
ret = _regmap_write(map, i, val);
map->cache_bypass = 0;
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
};