/* * 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/lzo.h> #include "internal.h" 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(void) { 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->cache_word_size) / DIV_ROUND_UP(map->cache_size_raw, regcache_lzo_block_count()); } static inline int regcache_lzo_get_blkpos(struct regmap *map, unsigned int reg) { return reg % (DIV_ROUND_UP(map->cache_size_raw, regcache_lzo_block_count()) / 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()); } 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->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_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(); /* * 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, 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) { struct regcache_lzo_ctx **lzo_blocks; unsigned int val; int i; int ret; lzo_blocks = map->cache; for_each_set_bit(i, lzo_blocks[0]->sync_bmp, lzo_blocks[0]->sync_bmp_nbits) { ret = regcache_read(map, i, &val); if (ret) return ret; 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 };