diff options
Diffstat (limited to 'drivers/base/regmap/regcache-lzo.c')
| -rw-r--r-- | drivers/base/regmap/regcache-lzo.c | 378 |
1 files changed, 378 insertions, 0 deletions
diff --git a/drivers/base/regmap/regcache-lzo.c b/drivers/base/regmap/regcache-lzo.c new file mode 100644 index 000000000..2d53f6f13 --- /dev/null +++ b/drivers/base/regmap/regcache-lzo.c @@ -0,0 +1,378 @@ +/* + * 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 = 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(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 = 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 +}; |