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/device.h>
  15 #include <linux/lzo.h>
  16
  17 #include "internal.h"
  18
  19 static int regcache_lzo_exit(struct regmap *map);
  20
  21 struct regcache_lzo_ctx {
  22         void *wmem;
  23         void *dst;
  24         const void *src;
  25         size_t src_len;
  26         size_t dst_len;
  27         size_t decompressed_size;
  28         unsigned long *sync_bmp;
  29         int sync_bmp_nbits;
  30 };
  31
  32 #define LZO_BLOCK_NUM 8
  33 static int regcache_lzo_block_count(struct regmap *map)
  34 {
  35         return LZO_BLOCK_NUM;
  36 }
  37
  38 static int regcache_lzo_prepare(struct regcache_lzo_ctx *lzo_ctx)
  39 {
  40         lzo_ctx->wmem = kmalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL);
  41         if (!lzo_ctx->wmem)
  42                 return -ENOMEM;
  43         return 0;
  44 }
  45
  46 static int regcache_lzo_compress(struct regcache_lzo_ctx *lzo_ctx)
  47 {
  48         size_t compress_size;
  49         int ret;
  50
  51         ret = lzo1x_1_compress(lzo_ctx->src, lzo_ctx->src_len,
  52                                lzo_ctx->dst, &compress_size, lzo_ctx->wmem);
  53         if (ret != LZO_E_OK || compress_size > lzo_ctx->dst_len)
  54                 return -EINVAL;
  55         lzo_ctx->dst_len = compress_size;
  56         return 0;
  57 }
  58
  59 static int regcache_lzo_decompress(struct regcache_lzo_ctx *lzo_ctx)
  60 {
  61         size_t dst_len;
  62         int ret;
  63
  64         dst_len = lzo_ctx->dst_len;
  65         ret = lzo1x_decompress_safe(lzo_ctx->src, lzo_ctx->src_len,
  66                                     lzo_ctx->dst, &dst_len);
  67         if (ret != LZO_E_OK || dst_len != lzo_ctx->dst_len)
  68                 return -EINVAL;
  69         return 0;
  70 }
  71
  72 static int regcache_lzo_compress_cache_block(struct regmap *map,
  73                 struct regcache_lzo_ctx *lzo_ctx)
  74 {
  75         int ret;
  76
  77         lzo_ctx->dst_len = lzo1x_worst_compress(PAGE_SIZE);
  78         lzo_ctx->dst = kmalloc(lzo_ctx->dst_len, GFP_KERNEL);
  79         if (!lzo_ctx->dst) {
  80                 lzo_ctx->dst_len = 0;
  81                 return -ENOMEM;
  82         }
  83
  84         ret = regcache_lzo_compress(lzo_ctx);
  85         if (ret < 0)
  86                 return ret;
  87         return 0;
  88 }
  89
  90 static int regcache_lzo_decompress_cache_block(struct regmap *map,
  91                 struct regcache_lzo_ctx *lzo_ctx)
  92 {
  93         int ret;
  94
  95         lzo_ctx->dst_len = lzo_ctx->decompressed_size;
  96         lzo_ctx->dst = kmalloc(lzo_ctx->dst_len, GFP_KERNEL);
  97         if (!lzo_ctx->dst) {
  98                 lzo_ctx->dst_len = 0;
  99                 return -ENOMEM;
 100         }
 101
 102         ret = regcache_lzo_decompress(lzo_ctx);
 103         if (ret < 0)
 104                 return ret;
 105         return 0;
 106 }
 107
 108 static inline int regcache_lzo_get_blkindex(struct regmap *map,
 109                                             unsigned int reg)
 110 {
 111         return (reg * map->cache_word_size) /
 112                 DIV_ROUND_UP(map->cache_size_raw,
 113                              regcache_lzo_block_count(map));
 114 }
 115
 116 static inline int regcache_lzo_get_blkpos(struct regmap *map,
 117                                           unsigned int reg)
 118 {
 119         return reg % (DIV_ROUND_UP(map->cache_size_raw,
 120                                    regcache_lzo_block_count(map)) /
 121                       map->cache_word_size);
 122 }
 123
 124 static inline int regcache_lzo_get_blksize(struct regmap *map)
 125 {
 126         return DIV_ROUND_UP(map->cache_size_raw,
 127                             regcache_lzo_block_count(map));
 128 }
 129
 130 static int regcache_lzo_init(struct regmap *map)
 131 {
 132         struct regcache_lzo_ctx **lzo_blocks;
 133         size_t bmp_size;
 134         int ret, i, blksize, blkcount;
 135         const char *p, *end;
 136         unsigned long *sync_bmp;
 137
 138         ret = 0;
 139
 140         blkcount = regcache_lzo_block_count(map);
 141         map->cache = kzalloc(blkcount * sizeof *lzo_blocks,
 142                              GFP_KERNEL);
 143         if (!map->cache)
 144                 return -ENOMEM;
 145         lzo_blocks = map->cache;
 146
 147         /*
 148          * allocate a bitmap to be used when syncing the cache with
 149          * the hardware.  Each time a register is modified, the corresponding
 150          * bit is set in the bitmap, so we know that we have to sync
 151          * that register.
 152          */
 153         bmp_size = map->num_reg_defaults_raw;
 154         sync_bmp = kmalloc(BITS_TO_LONGS(bmp_size) * sizeof(long),
 155                            GFP_KERNEL);
 156         if (!sync_bmp) {
 157                 ret = -ENOMEM;
 158                 goto err;
 159         }
 160         bitmap_zero(sync_bmp, bmp_size);
 161
 162         /* allocate the lzo blocks and initialize them */
 163         for (i = 0; i < blkcount; i++) {
 164                 lzo_blocks[i] = kzalloc(sizeof **lzo_blocks,
 165                                         GFP_KERNEL);
 166                 if (!lzo_blocks[i]) {
 167                         kfree(sync_bmp);
 168                         ret = -ENOMEM;
 169                         goto err;
 170                 }
 171                 lzo_blocks[i]->sync_bmp = sync_bmp;
 172                 lzo_blocks[i]->sync_bmp_nbits = bmp_size;
 173                 /* alloc the working space for the compressed block */
 174                 ret = regcache_lzo_prepare(lzo_blocks[i]);
 175                 if (ret < 0)
 176                         goto err;
 177         }
 178
 179         blksize = regcache_lzo_get_blksize(map);
 180         p = map->reg_defaults_raw;
 181         end = map->reg_defaults_raw + map->cache_size_raw;
 182         /* compress the register map and fill the lzo blocks */
 183         for (i = 0; i < blkcount; i++, p += blksize) {
 184                 lzo_blocks[i]->src = p;
 185                 if (p + blksize > end)
 186                         lzo_blocks[i]->src_len = end - p;
 187                 else
 188                         lzo_blocks[i]->src_len = blksize;
 189                 ret = regcache_lzo_compress_cache_block(map,
 190                                                        lzo_blocks[i]);
 191                 if (ret < 0)
 192                         goto err;
 193                 lzo_blocks[i]->decompressed_size =
 194                         lzo_blocks[i]->src_len;
 195         }
 196
 197         return 0;
 198 err:
 199         regcache_lzo_exit(map);
 200         return ret;
 201 }
 202
 203 static int regcache_lzo_exit(struct regmap *map)
 204 {
 205         struct regcache_lzo_ctx **lzo_blocks;
 206         int i, blkcount;
 207
 208         lzo_blocks = map->cache;
 209         if (!lzo_blocks)
 210                 return 0;
 211
 212         blkcount = regcache_lzo_block_count(map);
 213         /*
 214          * the pointer to the bitmap used for syncing the cache
 215          * is shared amongst all lzo_blocks.  Ensure it is freed
 216          * only once.
 217          */
 218         if (lzo_blocks[0])
 219                 kfree(lzo_blocks[0]->sync_bmp);
 220         for (i = 0; i < blkcount; i++) {
 221                 if (lzo_blocks[i]) {
 222                         kfree(lzo_blocks[i]->wmem);
 223                         kfree(lzo_blocks[i]->dst);
 224                 }
 225                 /* each lzo_block is a pointer returned by kmalloc or NULL */
 226                 kfree(lzo_blocks[i]);
 227         }
 228         kfree(lzo_blocks);
 229         map->cache = NULL;
 230         return 0;
 231 }
 232
 233 static int regcache_lzo_read(struct regmap *map,
 234                              unsigned int reg, unsigned int *value)
 235 {
 236         struct regcache_lzo_ctx *lzo_block, **lzo_blocks;
 237         int ret, blkindex, blkpos;
 238         size_t blksize, tmp_dst_len;
 239         void *tmp_dst;
 240
 241         /* index of the compressed lzo block */
 242         blkindex = regcache_lzo_get_blkindex(map, reg);
 243         /* register index within the decompressed block */
 244         blkpos = regcache_lzo_get_blkpos(map, reg);
 245         /* size of the compressed block */
 246         blksize = regcache_lzo_get_blksize(map);
 247         lzo_blocks = map->cache;
 248         lzo_block = lzo_blocks[blkindex];
 249
 250         /* save the pointer and length of the compressed block */
 251         tmp_dst = lzo_block->dst;
 252         tmp_dst_len = lzo_block->dst_len;
 253
 254         /* prepare the source to be the compressed block */
 255         lzo_block->src = lzo_block->dst;
 256         lzo_block->src_len = lzo_block->dst_len;
 257
 258         /* decompress the block */
 259         ret = regcache_lzo_decompress_cache_block(map, lzo_block);
 260         if (ret >= 0)
 261                 /* fetch the value from the cache */
 262                 *value = regcache_get_val(lzo_block->dst, blkpos,
 263                                           map->cache_word_size);
 264
 265         kfree(lzo_block->dst);
 266         /* restore the pointer and length of the compressed block */
 267         lzo_block->dst = tmp_dst;
 268         lzo_block->dst_len = tmp_dst_len;
 269
 270         return ret;
 271 }
 272
 273 static int regcache_lzo_write(struct regmap *map,
 274                               unsigned int reg, unsigned int value)
 275 {
 276         struct regcache_lzo_ctx *lzo_block, **lzo_blocks;
 277         int ret, blkindex, blkpos;
 278         size_t blksize, tmp_dst_len;
 279         void *tmp_dst;
 280
 281         /* index of the compressed lzo block */
 282         blkindex = regcache_lzo_get_blkindex(map, reg);
 283         /* register index within the decompressed block */
 284         blkpos = regcache_lzo_get_blkpos(map, reg);
 285         /* size of the compressed block */
 286         blksize = regcache_lzo_get_blksize(map);
 287         lzo_blocks = map->cache;
 288         lzo_block = lzo_blocks[blkindex];
 289
 290         /* save the pointer and length of the compressed block */
 291         tmp_dst = lzo_block->dst;
 292         tmp_dst_len = lzo_block->dst_len;
 293
 294         /* prepare the source to be the compressed block */
 295         lzo_block->src = lzo_block->dst;
 296         lzo_block->src_len = lzo_block->dst_len;
 297
 298         /* decompress the block */
 299         ret = regcache_lzo_decompress_cache_block(map, lzo_block);
 300         if (ret < 0) {
 301                 kfree(lzo_block->dst);
 302                 goto out;
 303         }
 304
 305         /* write the new value to the cache */
 306         if (regcache_set_val(lzo_block->dst, blkpos, value,
 307                              map->cache_word_size)) {
 308                 kfree(lzo_block->dst);
 309                 goto out;
 310         }
 311
 312         /* prepare the source to be the decompressed block */
 313         lzo_block->src = lzo_block->dst;
 314         lzo_block->src_len = lzo_block->dst_len;
 315
 316         /* compress the block */
 317         ret = regcache_lzo_compress_cache_block(map, lzo_block);
 318         if (ret < 0) {
 319                 kfree(lzo_block->dst);
 320                 kfree(lzo_block->src);
 321                 goto out;
 322         }
 323
 324         /* set the bit so we know we have to sync this register */
 325         set_bit(reg, lzo_block->sync_bmp);
 326         kfree(tmp_dst);
 327         kfree(lzo_block->src);
 328         return 0;
 329 out:
 330         lzo_block->dst = tmp_dst;
 331         lzo_block->dst_len = tmp_dst_len;
 332         return ret;
 333 }
 334
 335 static int regcache_lzo_sync(struct regmap *map, unsigned int min,
 336                              unsigned int max)
 337 {
 338         struct regcache_lzo_ctx **lzo_blocks;
 339         unsigned int val;
 340         int i;
 341         int ret;
 342
 343         lzo_blocks = map->cache;
 344         i = min;
 345         for_each_set_bit_from(i, lzo_blocks[0]->sync_bmp,
 346                               lzo_blocks[0]->sync_bmp_nbits) {
 347                 if (i > max)
 348                         continue;
 349
 350                 ret = regcache_read(map, i, &val);
 351                 if (ret)
 352                         return ret;
 353
 354                 /* Is this the hardware default?  If so skip. */
 355                 ret = regcache_lookup_reg(map, i);
 356                 if (ret > 0 && val == map->reg_defaults[ret].def)
 357                         continue;
 358
 359                 map->cache_bypass = 1;
 360                 ret = _regmap_write(map, i, val);
 361                 map->cache_bypass = 0;
 362                 if (ret)
 363                         return ret;
 364                 dev_dbg(map->dev, "Synced register %#x, value %#x\n",
 365                         i, val);
 366         }
 367
 368         return 0;
 369 }
 370
 371 struct regcache_ops regcache_lzo_ops = {
 372         .type = REGCACHE_COMPRESSED,
 373         .name = "lzo",
 374         .init = regcache_lzo_init,
 375         .exit = regcache_lzo_exit,
 376         .read = regcache_lzo_read,
 377         .write = regcache_lzo_write,
 378         .sync = regcache_lzo_sync
 379 };