drivers/base/regmap/regcache-rbtree.c

   1 /*
   2  * Register cache access API - rbtree 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/debugfs.h>
  16 #include <linux/rbtree.h>
  17 #include <linux/seq_file.h>
  18
  19 #include "internal.h"
  20
  21 static int regcache_rbtree_write(struct regmap *map, unsigned int reg,
  22                                  unsigned int value);
  23 static int regcache_rbtree_exit(struct regmap *map);
  24
  25 struct regcache_rbtree_node {
  26         /* block of adjacent registers */
  27         void *block;
  28         /* Which registers are present */
  29         long *cache_present;
  30         /* base register handled by this block */
  31         unsigned int base_reg;
  32         /* number of registers available in the block */
  33         unsigned int blklen;
  34         /* the actual rbtree node holding this block */
  35         struct rb_node node;
  36 } __attribute__ ((packed));
  37
  38 struct regcache_rbtree_ctx {
  39         struct rb_root root;
  40         struct regcache_rbtree_node *cached_rbnode;
  41 };
  42
  43 static inline void regcache_rbtree_get_base_top_reg(
  44         struct regmap *map,
  45         struct regcache_rbtree_node *rbnode,
  46         unsigned int *base, unsigned int *top)
  47 {
  48         *base = rbnode->base_reg;
  49         *top = rbnode->base_reg + ((rbnode->blklen - 1) * map->reg_stride);
  50 }
  51
  52 static unsigned int regcache_rbtree_get_register(struct regmap *map,
  53         struct regcache_rbtree_node *rbnode, unsigned int idx)
  54 {
  55         return regcache_get_val(map, rbnode->block, idx);
  56 }
  57
  58 static void regcache_rbtree_set_register(struct regmap *map,
  59                                          struct regcache_rbtree_node *rbnode,
  60                                          unsigned int idx, unsigned int val)
  61 {
  62         set_bit(idx, rbnode->cache_present);
  63         regcache_set_val(map, rbnode->block, idx, val);
  64 }
  65
  66 static struct regcache_rbtree_node *regcache_rbtree_lookup(struct regmap *map,
  67                                                            unsigned int reg)
  68 {
  69         struct regcache_rbtree_ctx *rbtree_ctx = map->cache;
  70         struct rb_node *node;
  71         struct regcache_rbtree_node *rbnode;
  72         unsigned int base_reg, top_reg;
  73
  74         rbnode = rbtree_ctx->cached_rbnode;
  75         if (rbnode) {
  76                 regcache_rbtree_get_base_top_reg(map, rbnode, &base_reg,
  77                                                  &top_reg);
  78                 if (reg >= base_reg && reg <= top_reg)
  79                         return rbnode;
  80         }
  81
  82         node = rbtree_ctx->root.rb_node;
  83         while (node) {
  84                 rbnode = container_of(node, struct regcache_rbtree_node, node);
  85                 regcache_rbtree_get_base_top_reg(map, rbnode, &base_reg,
  86                                                  &top_reg);
  87                 if (reg >= base_reg && reg <= top_reg) {
  88                         rbtree_ctx->cached_rbnode = rbnode;
  89                         return rbnode;
  90                 } else if (reg > top_reg) {
  91                         node = node->rb_right;
  92                 } else if (reg < base_reg) {
  93                         node = node->rb_left;
  94                 }
  95         }
  96
  97         return NULL;
  98 }
  99
 100 static int regcache_rbtree_insert(struct regmap *map, struct rb_root *root,
 101                                   struct regcache_rbtree_node *rbnode)
 102 {
 103         struct rb_node **new, *parent;
 104         struct regcache_rbtree_node *rbnode_tmp;
 105         unsigned int base_reg_tmp, top_reg_tmp;
 106         unsigned int base_reg;
 107
 108         parent = NULL;
 109         new = &root->rb_node;
 110         while (*new) {
 111                 rbnode_tmp = container_of(*new, struct regcache_rbtree_node,
 112                                           node);
 113                 /* base and top registers of the current rbnode */
 114                 regcache_rbtree_get_base_top_reg(map, rbnode_tmp, &base_reg_tmp,
 115                                                  &top_reg_tmp);
 116                 /* base register of the rbnode to be added */
 117                 base_reg = rbnode->base_reg;
 118                 parent = *new;
 119                 /* if this register has already been inserted, just return */
 120                 if (base_reg >= base_reg_tmp &&
 121                     base_reg <= top_reg_tmp)
 122                         return 0;
 123                 else if (base_reg > top_reg_tmp)
 124                         new = &((*new)->rb_right);
 125                 else if (base_reg < base_reg_tmp)
 126                         new = &((*new)->rb_left);
 127         }
 128
 129         /* insert the node into the rbtree */
 130         rb_link_node(&rbnode->node, parent, new);
 131         rb_insert_color(&rbnode->node, root);
 132
 133         return 1;
 134 }
 135
 136 #ifdef CONFIG_DEBUG_FS
 137 static int rbtree_show(struct seq_file *s, void *ignored)
 138 {
 139         struct regmap *map = s->private;
 140         struct regcache_rbtree_ctx *rbtree_ctx = map->cache;
 141         struct regcache_rbtree_node *n;
 142         struct rb_node *node;
 143         unsigned int base, top;
 144         size_t mem_size;
 145         int nodes = 0;
 146         int registers = 0;
 147         int this_registers, average;
 148
 149         map->lock(map->lock_arg);
 150
 151         mem_size = sizeof(*rbtree_ctx);
 152
 153         for (node = rb_first(&rbtree_ctx->root); node != NULL;
 154              node = rb_next(node)) {
 155                 n = container_of(node, struct regcache_rbtree_node, node);
 156                 mem_size += sizeof(*n);
 157                 mem_size += (n->blklen * map->cache_word_size);
 158                 mem_size += BITS_TO_LONGS(n->blklen) * sizeof(long);
 159
 160                 regcache_rbtree_get_base_top_reg(map, n, &base, &top);
 161                 this_registers = ((top - base) / map->reg_stride) + 1;
 162                 seq_printf(s, "%x-%x (%d)\n", base, top, this_registers);
 163
 164                 nodes++;
 165                 registers += this_registers;
 166         }
 167
 168         if (nodes)
 169                 average = registers / nodes;
 170         else
 171                 average = 0;
 172
 173         seq_printf(s, "%d nodes, %d registers, average %d registers, used %zu bytes\n",
 174                    nodes, registers, average, mem_size);
 175
 176         map->unlock(map->lock_arg);
 177
 178         return 0;
 179 }
 180
 181 static int rbtree_open(struct inode *inode, struct file *file)
 182 {
 183         return single_open(file, rbtree_show, inode->i_private);
 184 }
 185
 186 static const struct file_operations rbtree_fops = {
 187         .open           = rbtree_open,
 188         .read           = seq_read,
 189         .llseek         = seq_lseek,
 190         .release        = single_release,
 191 };
 192
 193 static void rbtree_debugfs_init(struct regmap *map)
 194 {
 195         debugfs_create_file("rbtree", 0400, map->debugfs, map, &rbtree_fops);
 196 }
 197 #else
 198 static void rbtree_debugfs_init(struct regmap *map)
 199 {
 200 }
 201 #endif
 202
 203 static int regcache_rbtree_init(struct regmap *map)
 204 {
 205         struct regcache_rbtree_ctx *rbtree_ctx;
 206         int i;
 207         int ret;
 208
 209         map->cache = kmalloc(sizeof *rbtree_ctx, GFP_KERNEL);
 210         if (!map->cache)
 211                 return -ENOMEM;
 212
 213         rbtree_ctx = map->cache;
 214         rbtree_ctx->root = RB_ROOT;
 215         rbtree_ctx->cached_rbnode = NULL;
 216
 217         for (i = 0; i < map->num_reg_defaults; i++) {
 218                 ret = regcache_rbtree_write(map,
 219                                             map->reg_defaults[i].reg,
 220                                             map->reg_defaults[i].def);
 221                 if (ret)
 222                         goto err;
 223         }
 224
 225         rbtree_debugfs_init(map);
 226
 227         return 0;
 228
 229 err:
 230         regcache_rbtree_exit(map);
 231         return ret;
 232 }
 233
 234 static int regcache_rbtree_exit(struct regmap *map)
 235 {
 236         struct rb_node *next;
 237         struct regcache_rbtree_ctx *rbtree_ctx;
 238         struct regcache_rbtree_node *rbtree_node;
 239
 240         /* if we've already been called then just return */
 241         rbtree_ctx = map->cache;
 242         if (!rbtree_ctx)
 243                 return 0;
 244
 245         /* free up the rbtree */
 246         next = rb_first(&rbtree_ctx->root);
 247         while (next) {
 248                 rbtree_node = rb_entry(next, struct regcache_rbtree_node, node);
 249                 next = rb_next(&rbtree_node->node);
 250                 rb_erase(&rbtree_node->node, &rbtree_ctx->root);
 251                 kfree(rbtree_node->cache_present);
 252                 kfree(rbtree_node->block);
 253                 kfree(rbtree_node);
 254         }
 255
 256         /* release the resources */
 257         kfree(map->cache);
 258         map->cache = NULL;
 259
 260         return 0;
 261 }
 262
 263 static int regcache_rbtree_read(struct regmap *map,
 264                                 unsigned int reg, unsigned int *value)
 265 {
 266         struct regcache_rbtree_node *rbnode;
 267         unsigned int reg_tmp;
 268
 269         rbnode = regcache_rbtree_lookup(map, reg);
 270         if (rbnode) {
 271                 reg_tmp = (reg - rbnode->base_reg) / map->reg_stride;
 272                 if (!test_bit(reg_tmp, rbnode->cache_present))
 273                         return -ENOENT;
 274                 *value = regcache_rbtree_get_register(map, rbnode, reg_tmp);
 275         } else {
 276                 return -ENOENT;
 277         }
 278
 279         return 0;
 280 }
 281
 282
 283 static int regcache_rbtree_insert_to_block(struct regmap *map,
 284                                            struct regcache_rbtree_node *rbnode,
 285                                            unsigned int base_reg,
 286                                            unsigned int top_reg,
 287                                            unsigned int reg,
 288                                            unsigned int value)
 289 {
 290         unsigned int blklen;
 291         unsigned int pos, offset;
 292         unsigned long *present;
 293         u8 *blk;
 294
 295         blklen = (top_reg - base_reg) / map->reg_stride + 1;
 296         pos = (reg - base_reg) / map->reg_stride;
 297         offset = (rbnode->base_reg - base_reg) / map->reg_stride;
 298
 299         blk = krealloc(rbnode->block,
 300                        blklen * map->cache_word_size,
 301                        GFP_KERNEL);
 302         if (!blk)
 303                 return -ENOMEM;
 304
 305         present = krealloc(rbnode->cache_present,
 306                     BITS_TO_LONGS(blklen) * sizeof(*present), GFP_KERNEL);
 307         if (!present) {
 308                 kfree(blk);
 309                 return -ENOMEM;
 310         }
 311
 312         /* insert the register value in the correct place in the rbnode block */
 313         if (pos == 0) {
 314                 memmove(blk + offset * map->cache_word_size,
 315                         blk, rbnode->blklen * map->cache_word_size);
 316                 bitmap_shift_right(present, present, offset, blklen);
 317         }
 318
 319         /* update the rbnode block, its size and the base register */
 320         rbnode->block = blk;
 321         rbnode->blklen = blklen;
 322         rbnode->base_reg = base_reg;
 323         rbnode->cache_present = present;
 324
 325         regcache_rbtree_set_register(map, rbnode, pos, value);
 326         return 0;
 327 }
 328
 329 static struct regcache_rbtree_node *
 330 regcache_rbtree_node_alloc(struct regmap *map, unsigned int reg)
 331 {
 332         struct regcache_rbtree_node *rbnode;
 333         const struct regmap_range *range;
 334         int i;
 335
 336         rbnode = kzalloc(sizeof(*rbnode), GFP_KERNEL);
 337         if (!rbnode)
 338                 return NULL;
 339
 340         /* If there is a read table then use it to guess at an allocation */
 341         if (map->rd_table) {
 342                 for (i = 0; i < map->rd_table->n_yes_ranges; i++) {
 343                         if (regmap_reg_in_range(reg,
 344                                                 &map->rd_table->yes_ranges[i]))
 345                                 break;
 346                 }
 347
 348                 if (i != map->rd_table->n_yes_ranges) {
 349                         range = &map->rd_table->yes_ranges[i];
 350                         rbnode->blklen = (range->range_max - range->range_min) /
 351                                 map->reg_stride + 1;
 352                         rbnode->base_reg = range->range_min;
 353                 }
 354         }
 355
 356         if (!rbnode->blklen) {
 357                 rbnode->blklen = 1;
 358                 rbnode->base_reg = reg;
 359         }
 360
 361         rbnode->block = kmalloc(rbnode->blklen * map->cache_word_size,
 362                                 GFP_KERNEL);
 363         if (!rbnode->block)
 364                 goto err_free;
 365
 366         rbnode->cache_present = kzalloc(BITS_TO_LONGS(rbnode->blklen) *
 367                 sizeof(*rbnode->cache_present), GFP_KERNEL);
 368         if (!rbnode->cache_present)
 369                 goto err_free_block;
 370
 371         return rbnode;
 372
 373 err_free_block:
 374         kfree(rbnode->block);
 375 err_free:
 376         kfree(rbnode);
 377         return NULL;
 378 }
 379
 380 static int regcache_rbtree_write(struct regmap *map, unsigned int reg,
 381                                  unsigned int value)
 382 {
 383         struct regcache_rbtree_ctx *rbtree_ctx;
 384         struct regcache_rbtree_node *rbnode, *rbnode_tmp;
 385         struct rb_node *node;
 386         unsigned int reg_tmp;
 387         int ret;
 388
 389         rbtree_ctx = map->cache;
 390
 391         /* if we can't locate it in the cached rbnode we'll have
 392          * to traverse the rbtree looking for it.
 393          */
 394         rbnode = regcache_rbtree_lookup(map, reg);
 395         if (rbnode) {
 396                 reg_tmp = (reg - rbnode->base_reg) / map->reg_stride;
 397                 regcache_rbtree_set_register(map, rbnode, reg_tmp, value);
 398         } else {
 399                 unsigned int base_reg, top_reg;
 400                 unsigned int new_base_reg, new_top_reg;
 401                 unsigned int min, max;
 402                 unsigned int max_dist;
 403
 404                 max_dist = map->reg_stride * sizeof(*rbnode_tmp) /
 405                         map->cache_word_size;
 406                 if (reg < max_dist)
 407                         min = 0;
 408                 else
 409                         min = reg - max_dist;
 410                 max = reg + max_dist;
 411
 412                 /* look for an adjacent register to the one we are about to add */
 413                 for (node = rb_first(&rbtree_ctx->root); node;
 414                      node = rb_next(node)) {
 415                         rbnode_tmp = rb_entry(node, struct regcache_rbtree_node,
 416                                               node);
 417
 418                         regcache_rbtree_get_base_top_reg(map, rbnode_tmp,
 419                                 &base_reg, &top_reg);
 420
 421                         if (base_reg <= max && top_reg >= min) {
 422                                 new_base_reg = min(reg, base_reg);
 423                                 new_top_reg = max(reg, top_reg);
 424                         } else {
 425                                 continue;
 426                         }
 427
 428                         ret = regcache_rbtree_insert_to_block(map, rbnode_tmp,
 429                                                               new_base_reg,
 430                                                               new_top_reg, reg,
 431                                                               value);
 432                         if (ret)
 433                                 return ret;
 434                         rbtree_ctx->cached_rbnode = rbnode_tmp;
 435                         return 0;
 436                 }
 437
 438                 /* We did not manage to find a place to insert it in
 439                  * an existing block so create a new rbnode.
 440                  */
 441                 rbnode = regcache_rbtree_node_alloc(map, reg);
 442                 if (!rbnode)
 443                         return -ENOMEM;
 444                 regcache_rbtree_set_register(map, rbnode,
 445                                              reg - rbnode->base_reg, value);
 446                 regcache_rbtree_insert(map, &rbtree_ctx->root, rbnode);
 447                 rbtree_ctx->cached_rbnode = rbnode;
 448         }
 449
 450         return 0;
 451 }
 452
 453 static int regcache_rbtree_sync(struct regmap *map, unsigned int min,
 454                                 unsigned int max)
 455 {
 456         struct regcache_rbtree_ctx *rbtree_ctx;
 457         struct rb_node *node;
 458         struct regcache_rbtree_node *rbnode;
 459         unsigned int base_reg, top_reg;
 460         unsigned int start, end;
 461         int ret;
 462
 463         rbtree_ctx = map->cache;
 464         for (node = rb_first(&rbtree_ctx->root); node; node = rb_next(node)) {
 465                 rbnode = rb_entry(node, struct regcache_rbtree_node, node);
 466
 467                 regcache_rbtree_get_base_top_reg(map, rbnode, &base_reg,
 468                         &top_reg);
 469                 if (base_reg > max)
 470                         break;
 471                 if (top_reg < min)
 472                         continue;
 473
 474                 if (min > base_reg)
 475                         start = (min - base_reg) / map->reg_stride;
 476                 else
 477                         start = 0;
 478
 479                 if (max < top_reg)
 480                         end = (max - base_reg) / map->reg_stride + 1;
 481                 else
 482                         end = rbnode->blklen;
 483
 484                 ret = regcache_sync_block(map, rbnode->block,
 485                                           rbnode->cache_present,
 486                                           rbnode->base_reg, start, end);
 487                 if (ret != 0)
 488                         return ret;
 489         }
 490
 491         return regmap_async_complete(map);
 492 }
 493
 494 static int regcache_rbtree_drop(struct regmap *map, unsigned int min,
 495                                 unsigned int max)
 496 {
 497         struct regcache_rbtree_ctx *rbtree_ctx;
 498         struct regcache_rbtree_node *rbnode;
 499         struct rb_node *node;
 500         unsigned int base_reg, top_reg;
 501         unsigned int start, end;
 502
 503         rbtree_ctx = map->cache;
 504         for (node = rb_first(&rbtree_ctx->root); node; node = rb_next(node)) {
 505                 rbnode = rb_entry(node, struct regcache_rbtree_node, node);
 506
 507                 regcache_rbtree_get_base_top_reg(map, rbnode, &base_reg,
 508                         &top_reg);
 509                 if (base_reg > max)
 510                         break;
 511                 if (top_reg < min)
 512                         continue;
 513
 514                 if (min > base_reg)
 515                         start = (min - base_reg) / map->reg_stride;
 516                 else
 517                         start = 0;
 518
 519                 if (max < top_reg)
 520                         end = (max - base_reg) / map->reg_stride + 1;
 521                 else
 522                         end = rbnode->blklen;
 523
 524                 bitmap_clear(rbnode->cache_present, start, end - start);
 525         }
 526
 527         return 0;
 528 }
 529
 530 struct regcache_ops regcache_rbtree_ops = {
 531         .type = REGCACHE_RBTREE,
 532         .name = "rbtree",
 533         .init = regcache_rbtree_init,
 534         .exit = regcache_rbtree_exit,
 535         .read = regcache_rbtree_read,
 536         .write = regcache_rbtree_write,
 537         .sync = regcache_rbtree_sync,
 538         .drop = regcache_rbtree_drop,
 539 };