drivers/base/regmap/regcache-lzo.c

   1 /*
   2  * Register cache access API - LZO caching support
   3  *
   4  * Copyright 2011 Wolfson Microelectronics plc
   5  *
   6  * Author: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/slab.h>
  14 #include <linux/lzo.h>
  15
  16 #include "internal.h"
  17
  18 static int regcache_lzo_exit(struct regmap *map);
  19
  20 struct regcache_lzo_ctx {
  21         void *wmem;
  22         void *dst;
  23         const void *src;
  24         size_t src_len;
  25         size_t dst_len;
  26         size_t decompressed_size;
  27         unsigned long *sync_bmp;
  28         int sync_bmp_nbits;
  29 };
  30
  31 #define LZO_BLOCK_NUM 8
  32 static int regcache_lzo_block_count(struct regmap *map)
  33 {
  34         return LZO_BLOCK_NUM;
  35 }
  36
  37 static int regcache_lzo_prepare(struct regcache_lzo_ctx *lzo_ctx)
  38 {
  39         lzo_ctx->wmem = kmalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL);
  40         if (!lzo_ctx->wmem)
  41                 return -ENOMEM;
  42         return 0;
  43 }
  44
  45 static int regcache_lzo_compress(struct regcache_lzo_ctx *lzo_ctx)
  46 {
  47         size_t compress_size;
  48         int ret;
  49
  50         ret = lzo1x_1_compress(lzo_ctx->src, lzo_ctx->src_len,
  51                                lzo_ctx->dst, &compress_size, lzo_ctx->wmem);
  52         if (ret != LZO_E_OK || compress_size > lzo_ctx->dst_len)
  53                 return -EINVAL;
  54         lzo_ctx->dst_len = compress_size;
  55         return 0;
  56 }
  57
  58 static int regcache_lzo_decompress(struct regcache_lzo_ctx *lzo_ctx)
  59 {
  60         size_t dst_len;
  61         int ret;
  62
  63         dst_len = lzo_ctx->dst_len;
  64         ret = lzo1x_decompress_safe(lzo_ctx->src, lzo_ctx->src_len,
  65                                     lzo_ctx->dst, &dst_len);
  66         if (ret != LZO_E_OK || dst_len != lzo_ctx->dst_len)
  67                 return -EINVAL;
  68         return 0;
  69 }
  70
  71 static int regcache_lzo_compress_cache_block(struct regmap *map,
  72                 struct regcache_lzo_ctx *lzo_ctx)
  73 {
  74         int ret;
  75
  76         lzo_ctx->dst_len = lzo1x_worst_compress(PAGE_SIZE);
  77         lzo_ctx->dst = kmalloc(lzo_ctx->dst_len, GFP_KERNEL);
  78         if (!lzo_ctx->dst) {
  79                 lzo_ctx->dst_len = 0;
  80                 return -ENOMEM;
  81         }
  82
  83         ret = regcache_lzo_compress(lzo_ctx);
  84         if (ret < 0)
  85                 return ret;
  86         return 0;
  87 }
  88
  89 static int regcache_lzo_decompress_cache_block(struct regmap *map,
  90                 struct regcache_lzo_ctx *lzo_ctx)
  91 {
  92         int ret;
  93
  94         lzo_ctx->dst_len = lzo_ctx->decompressed_size;
  95         lzo_ctx->dst = kmalloc(lzo_ctx->dst_len, GFP_KERNEL);
  96         if (!lzo_ctx->dst) {
  97                 lzo_ctx->dst_len = 0;
  98                 return -ENOMEM;
  99         }
 100
 101         ret = regcache_lzo_decompress(lzo_ctx);
 102         if (ret < 0)
 103                 return ret;
 104         return 0;
 105 }
 106
 107 static inline int regcache_lzo_get_blkindex(struct regmap *map,
 108                                             unsigned int reg)
 109 {
 110         return (reg * map->cache_word_size) /
 111                 DIV_ROUND_UP(map->cache_size_raw,
 112                              regcache_lzo_block_count(map));
 113 }
 114
 115 static inline int regcache_lzo_get_blkpos(struct regmap *map,
 116                                           unsigned int reg)
 117 {
 118         return reg % (DIV_ROUND_UP(map->cache_size_raw,
 119                                    regcache_lzo_block_count(map)) /
 120                       map->cache_word_size);
 121 }
 122
 123 static inline int regcache_lzo_get_blksize(struct regmap *map)
 124 {
 125         return DIV_ROUND_UP(map->cache_size_raw,
 126                             regcache_lzo_block_count(map));
 127 }
 128
 129 static int regcache_lzo_init(struct regmap *map)
 130 {
 131         struct regcache_lzo_ctx **lzo_blocks;
 132         size_t bmp_size;
 133         int ret, i, blksize, blkcount;
 134         const char *p, *end;
 135         unsigned long *sync_bmp;
 136
 137         ret = 0;
 138
 139         blkcount = regcache_lzo_block_count(map);
 140         map->cache = kzalloc(blkcount * sizeof *lzo_blocks,
 141                              GFP_KERNEL);
 142         if (!map->cache)
 143                 return -ENOMEM;
 144         lzo_blocks = map->cache;
 145
 146         /*
 147          * allocate a bitmap to be used when syncing the cache with
 148          * the hardware.  Each time a register is modified, the corresponding
 149          * bit is set in the bitmap, so we know that we have to sync
 150          * that register.
 151          */
 152         bmp_size = map->num_reg_defaults_raw;
 153         sync_bmp = kmalloc(BITS_TO_LONGS(bmp_size) * sizeof(long),
 154                            GFP_KERNEL);
 155         if (!sync_bmp) {
 156                 ret = -ENOMEM;
 157                 goto err;
 158         }
 159         bitmap_zero(sync_bmp, bmp_size);
 160
 161         /* allocate the lzo blocks and initialize them */
 162         for (i = 0; i < blkcount; i++) {
 163                 lzo_blocks[i] = kzalloc(sizeof **lzo_blocks,
 164                                         GFP_KERNEL);
 165                 if (!lzo_blocks[i]) {
 166                         kfree(sync_bmp);
 167                         ret = -ENOMEM;
 168                         goto err;
 169                 }
 170                 lzo_blocks[i]->sync_bmp = sync_bmp;
 171                 lzo_blocks[i]->sync_bmp_nbits = bmp_size;
 172                 /* alloc the working space for the compressed block */
 173                 ret = regcache_lzo_prepare(lzo_blocks[i]);
 174                 if (ret < 0)
 175                         goto err;
 176         }
 177
 178         blksize = regcache_lzo_get_blksize(map);
 179         p = map->reg_defaults_raw;
 180         end = map->reg_defaults_raw + map->cache_size_raw;
 181         /* compress the register map and fill the lzo blocks */
 182         for (i = 0; i < blkcount; i++, p += blksize) {
 183                 lzo_blocks[i]->src = p;
 184                 if (p + blksize > end)
 185                         lzo_blocks[i]->src_len = end - p;
 186                 else
 187                         lzo_blocks[i]->src_len = blksize;
 188                 ret = regcache_lzo_compress_cache_block(map,
 189                                                        lzo_blocks[i]);
 190                 if (ret < 0)
 191                         goto err;
 192                 lzo_blocks[i]->decompressed_size =
 193                         lzo_blocks[i]->src_len;
 194         }
 195
 196         return 0;
 197 err:
 198         regcache_lzo_exit(map);
 199         return ret;
 200 }
 201
 202 static int regcache_lzo_exit(struct regmap *map)
 203 {
 204         struct regcache_lzo_ctx **lzo_blocks;
 205         int i, blkcount;
 206
 207         lzo_blocks = map->cache;
 208         if (!lzo_blocks)
 209                 return 0;
 210
 211         blkcount = regcache_lzo_block_count(map);
 212         /*
 213          * the pointer to the bitmap used for syncing the cache
 214          * is shared amongst all lzo_blocks.  Ensure it is freed
 215          * only once.
 216          */
 217         if (lzo_blocks[0])
 218                 kfree(lzo_blocks[0]->sync_bmp);
 219         for (i = 0; i < blkcount; i++) {
 220                 if (lzo_blocks[i]) {
 221                         kfree(lzo_blocks[i]->wmem);
 222                         kfree(lzo_blocks[i]->dst);
 223                 }
 224                 /* each lzo_block is a pointer returned by kmalloc or NULL */
 225                 kfree(lzo_blocks[i]);
 226         }
 227         kfree(lzo_blocks);
 228         map->cache = NULL;
 229         return 0;
 230 }
 231
 232 static int regcache_lzo_read(struct regmap *map,
 233                              unsigned int reg, unsigned int *value)
 234 {
 235         struct regcache_lzo_ctx *lzo_block, **lzo_blocks;
 236         int ret, blkindex, blkpos;
 237         size_t blksize, tmp_dst_len;
 238         void *tmp_dst;
 239
 240         /* index of the compressed lzo block */
 241         blkindex = regcache_lzo_get_blkindex(map, reg);
 242         /* register index within the decompressed block */
 243         blkpos = regcache_lzo_get_blkpos(map, reg);
 244         /* size of the compressed block */
 245         blksize = regcache_lzo_get_blksize(map);
 246         lzo_blocks = map->cache;
 247         lzo_block = lzo_blocks[blkindex];
 248
 249         /* save the pointer and length of the compressed block */
 250         tmp_dst = lzo_block->dst;
 251         tmp_dst_len = lzo_block->dst_len;
 252
 253         /* prepare the source to be the compressed block */
 254         lzo_block->src = lzo_block->dst;
 255         lzo_block->src_len = lzo_block->dst_len;
 256
 257         /* decompress the block */
 258         ret = regcache_lzo_decompress_cache_block(map, lzo_block);
 259         if (ret >= 0)
 260                 /* fetch the value from the cache */
 261                 *value = regcache_get_val(lzo_block->dst, blkpos,
 262                                           map->cache_word_size);
 263
 264         kfree(lzo_block->dst);
 265         /* restore the pointer and length of the compressed block */
 266         lzo_block->dst = tmp_dst;
 267         lzo_block->dst_len = tmp_dst_len;
 268
 269         return ret;
 270 }
 271
 272 static int regcache_lzo_write(struct regmap *map,
 273                               unsigned int reg, unsigned int value)
 274 {
 275         struct regcache_lzo_ctx *lzo_block, **lzo_blocks;
 276         int ret, blkindex, blkpos;
 277         size_t blksize, tmp_dst_len;
 278         void *tmp_dst;
 279
 280         /* index of the compressed lzo block */
 281         blkindex = regcache_lzo_get_blkindex(map, reg);
 282         /* register index within the decompressed block */
 283         blkpos = regcache_lzo_get_blkpos(map, reg);
 284         /* size of the compressed block */
 285         blksize = regcache_lzo_get_blksize(map);
 286         lzo_blocks = map->cache;
 287         lzo_block = lzo_blocks[blkindex];
 288
 289         /* save the pointer and length of the compressed block */
 290         tmp_dst = lzo_block->dst;
 291         tmp_dst_len = lzo_block->dst_len;
 292
 293         /* prepare the source to be the compressed block */
 294         lzo_block->src = lzo_block->dst;
 295         lzo_block->src_len = lzo_block->dst_len;
 296
 297         /* decompress the block */
 298         ret = regcache_lzo_decompress_cache_block(map, lzo_block);
 299         if (ret < 0) {
 300                 kfree(lzo_block->dst);
 301                 goto out;
 302         }
 303
 304         /* write the new value to the cache */
 305         if (regcache_set_val(lzo_block->dst, blkpos, value,
 306                              map->cache_word_size)) {
 307                 kfree(lzo_block->dst);
 308                 goto out;
 309         }
 310
 311         /* prepare the source to be the decompressed block */
 312         lzo_block->src = lzo_block->dst;
 313         lzo_block->src_len = lzo_block->dst_len;
 314
 315         /* compress the block */
 316         ret = regcache_lzo_compress_cache_block(map, lzo_block);
 317         if (ret < 0) {
 318                 kfree(lzo_block->dst);
 319                 kfree(lzo_block->src);
 320                 goto out;
 321         }
 322
 323         /* set the bit so we know we have to sync this register */
 324         set_bit(reg, lzo_block->sync_bmp);
 325         kfree(tmp_dst);
 326         kfree(lzo_block->src);
 327         return 0;
 328 out:
 329         lzo_block->dst = tmp_dst;
 330         lzo_block->dst_len = tmp_dst_len;
 331         return ret;
 332 }
 333
 334 static int regcache_lzo_sync(struct regmap *map)
 335 {
 336         struct regcache_lzo_ctx **lzo_blocks;
 337         unsigned int val;
 338         int i;
 339         int ret;
 340
 341         lzo_blocks = map->cache;
 342         for_each_set_bit(i, lzo_blocks[0]->sync_bmp, lzo_blocks[0]->sync_bmp_nbits) {
 343                 ret = regcache_read(map, i, &val);
 344                 if (ret)
 345                         return ret;
 346                 map->cache_bypass = 1;
 347                 ret = _regmap_write(map, i, val);
 348                 map->cache_bypass = 0;
 349                 if (ret)
 350                         return ret;
 351                 dev_dbg(map->dev, "Synced register %#x, value %#x\n",
 352                         i, val);
 353         }
 354
 355         return 0;
 356 }
 357
 358 struct regcache_ops regcache_lzo_ops = {
 359         .type = REGCACHE_COMPRESSED,
 360         .name = "lzo",
 361         .init = regcache_lzo_init,
 362         .exit = regcache_lzo_exit,
 363         .read = regcache_lzo_read,
 364         .write = regcache_lzo_write,
 365         .sync = regcache_lzo_sync
 366 };