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/debugfs.h>
  14 #include <linux/device.h>
  15 #include <linux/rbtree.h>
  16 #include <linux/seq_file.h>
  17 #include <linux/slab.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 #endif
 198
 199 static int regcache_rbtree_init(struct regmap *map)
 200 {
 201         struct regcache_rbtree_ctx *rbtree_ctx;
 202         int i;
 203         int ret;
 204
 205         map->cache = kmalloc(sizeof *rbtree_ctx, GFP_KERNEL);
 206         if (!map->cache)
 207                 return -ENOMEM;
 208
 209         rbtree_ctx = map->cache;
 210         rbtree_ctx->root = RB_ROOT;
 211         rbtree_ctx->cached_rbnode = NULL;
 212
 213         for (i = 0; i < map->num_reg_defaults; i++) {
 214                 ret = regcache_rbtree_write(map,
 215                                             map->reg_defaults[i].reg,
 216                                             map->reg_defaults[i].def);
 217                 if (ret)
 218                         goto err;
 219         }
 220
 221         return 0;
 222
 223 err:
 224         regcache_rbtree_exit(map);
 225         return ret;
 226 }
 227
 228 static int regcache_rbtree_exit(struct regmap *map)
 229 {
 230         struct rb_node *next;
 231         struct regcache_rbtree_ctx *rbtree_ctx;
 232         struct regcache_rbtree_node *rbtree_node;
 233
 234         /* if we've already been called then just return */
 235         rbtree_ctx = map->cache;
 236         if (!rbtree_ctx)
 237                 return 0;
 238
 239         /* free up the rbtree */
 240         next = rb_first(&rbtree_ctx->root);
 241         while (next) {
 242                 rbtree_node = rb_entry(next, struct regcache_rbtree_node, node);
 243                 next = rb_next(&rbtree_node->node);
 244                 rb_erase(&rbtree_node->node, &rbtree_ctx->root);
 245                 kfree(rbtree_node->cache_present);
 246                 kfree(rbtree_node->block);
 247                 kfree(rbtree_node);
 248         }
 249
 250         /* release the resources */
 251         kfree(map->cache);
 252         map->cache = NULL;
 253
 254         return 0;
 255 }
 256
 257 static int regcache_rbtree_read(struct regmap *map,
 258                                 unsigned int reg, unsigned int *value)
 259 {
 260         struct regcache_rbtree_node *rbnode;
 261         unsigned int reg_tmp;
 262
 263         rbnode = regcache_rbtree_lookup(map, reg);
 264         if (rbnode) {
 265                 reg_tmp = (reg - rbnode->base_reg) / map->reg_stride;
 266                 if (!test_bit(reg_tmp, rbnode->cache_present))
 267                         return -ENOENT;
 268                 *value = regcache_rbtree_get_register(map, rbnode, reg_tmp);
 269         } else {
 270                 return -ENOENT;
 271         }
 272
 273         return 0;
 274 }
 275
 276
 277 static int regcache_rbtree_insert_to_block(struct regmap *map,
 278                                            struct regcache_rbtree_node *rbnode,
 279                                            unsigned int base_reg,
 280                                            unsigned int top_reg,
 281                                            unsigned int reg,
 282                                            unsigned int value)
 283 {
 284         unsigned int blklen;
 285         unsigned int pos, offset;
 286         unsigned long *present;
 287         u8 *blk;
 288
 289         blklen = (top_reg - base_reg) / map->reg_stride + 1;
 290         pos = (reg - base_reg) / map->reg_stride;
 291         offset = (rbnode->base_reg - base_reg) / map->reg_stride;
 292
 293         blk = krealloc(rbnode->block,
 294                        blklen * map->cache_word_size,
 295                        GFP_KERNEL);
 296         if (!blk)
 297                 return -ENOMEM;
 298
 299         if (BITS_TO_LONGS(blklen) > BITS_TO_LONGS(rbnode->blklen)) {
 300                 present = krealloc(rbnode->cache_present,
 301                                    BITS_TO_LONGS(blklen) * sizeof(*present),
 302                                    GFP_KERNEL);
 303                 if (!present) {
 304                         kfree(blk);
 305                         return -ENOMEM;
 306                 }
 307
 308                 memset(present + BITS_TO_LONGS(rbnode->blklen), 0,
 309                        (BITS_TO_LONGS(blklen) - BITS_TO_LONGS(rbnode->blklen))
 310                        * sizeof(*present));
 311         } else {
 312                 present = rbnode->cache_present;
 313         }
 314
 315         /* insert the register value in the correct place in the rbnode block */
 316         if (pos == 0) {
 317                 memmove(blk + offset * map->cache_word_size,
 318                         blk, rbnode->blklen * map->cache_word_size);
 319                 bitmap_shift_left(present, present, offset, blklen);
 320         }
 321
 322         /* update the rbnode block, its size and the base register */
 323         rbnode->block = blk;
 324         rbnode->blklen = blklen;
 325         rbnode->base_reg = base_reg;
 326         rbnode->cache_present = present;
 327
 328         regcache_rbtree_set_register(map, rbnode, pos, value);
 329         return 0;
 330 }
 331
 332 static struct regcache_rbtree_node *
 333 regcache_rbtree_node_alloc(struct regmap *map, unsigned int reg)
 334 {
 335         struct regcache_rbtree_node *rbnode;
 336         const struct regmap_range *range;
 337         int i;
 338
 339         rbnode = kzalloc(sizeof(*rbnode), GFP_KERNEL);
 340         if (!rbnode)
 341                 return NULL;
 342
 343         /* If there is a read table then use it to guess at an allocation */
 344         if (map->rd_table) {
 345                 for (i = 0; i < map->rd_table->n_yes_ranges; i++) {
 346                         if (regmap_reg_in_range(reg,
 347                                                 &map->rd_table->yes_ranges[i]))
 348                                 break;
 349                 }
 350
 351                 if (i != map->rd_table->n_yes_ranges) {
 352                         range = &map->rd_table->yes_ranges[i];
 353                         rbnode->blklen = (range->range_max - range->range_min) /
 354                                 map->reg_stride + 1;
 355                         rbnode->base_reg = range->range_min;
 356                 }
 357         }
 358
 359         if (!rbnode->blklen) {
 360                 rbnode->blklen = 1;
 361                 rbnode->base_reg = reg;
 362         }
 363
 364         rbnode->block = kmalloc_array(rbnode->blklen, map->cache_word_size,
 365                                       GFP_KERNEL);
 366         if (!rbnode->block)
 367                 goto err_free;
 368
 369         rbnode->cache_present = kcalloc(BITS_TO_LONGS(rbnode->blklen),
 370                                         sizeof(*rbnode->cache_present),
 371                                         GFP_KERNEL);
 372         if (!rbnode->cache_present)
 373                 goto err_free_block;
 374
 375         return rbnode;
 376
 377 err_free_block:
 378         kfree(rbnode->block);
 379 err_free:
 380         kfree(rbnode);
 381         return NULL;
 382 }
 383
 384 static int regcache_rbtree_write(struct regmap *map, unsigned int reg,
 385                                  unsigned int value)
 386 {
 387         struct regcache_rbtree_ctx *rbtree_ctx;
 388         struct regcache_rbtree_node *rbnode, *rbnode_tmp;
 389         struct rb_node *node;
 390         unsigned int reg_tmp;
 391         int ret;
 392
 393         rbtree_ctx = map->cache;
 394
 395         /* if we can't locate it in the cached rbnode we'll have
 396          * to traverse the rbtree looking for it.
 397          */
 398         rbnode = regcache_rbtree_lookup(map, reg);
 399         if (rbnode) {
 400                 reg_tmp = (reg - rbnode->base_reg) / map->reg_stride;
 401                 regcache_rbtree_set_register(map, rbnode, reg_tmp, value);
 402         } else {
 403                 unsigned int base_reg, top_reg;
 404                 unsigned int new_base_reg, new_top_reg;
 405                 unsigned int min, max;
 406                 unsigned int max_dist;
 407
 408                 max_dist = map->reg_stride * sizeof(*rbnode_tmp) /
 409                         map->cache_word_size;
 410                 if (reg < max_dist)
 411                         min = 0;
 412                 else
 413                         min = reg - max_dist;
 414                 max = reg + max_dist;
 415
 416                 /* look for an adjacent register to the one we are about to add */
 417                 node = rbtree_ctx->root.rb_node;
 418                 while (node) {
 419                         rbnode_tmp = rb_entry(node, struct regcache_rbtree_node,
 420                                               node);
 421
 422                         regcache_rbtree_get_base_top_reg(map, rbnode_tmp,
 423                                 &base_reg, &top_reg);
 424
 425                         if (base_reg <= max && top_reg >= min) {
 426                                 new_base_reg = min(reg, base_reg);
 427                                 new_top_reg = max(reg, top_reg);
 428                         } else {
 429                                 if (max < base_reg)
 430                                         node = node->rb_left;
 431                                 else
 432                                         node = node->rb_right;
 433
 434                                 continue;
 435                         }
 436
 437                         ret = regcache_rbtree_insert_to_block(map, rbnode_tmp,
 438                                                               new_base_reg,
 439                                                               new_top_reg, reg,
 440                                                               value);
 441                         if (ret)
 442                                 return ret;
 443                         rbtree_ctx->cached_rbnode = rbnode_tmp;
 444                         return 0;
 445                 }
 446
 447                 /* We did not manage to find a place to insert it in
 448                  * an existing block so create a new rbnode.
 449                  */
 450                 rbnode = regcache_rbtree_node_alloc(map, reg);
 451                 if (!rbnode)
 452                         return -ENOMEM;
 453                 regcache_rbtree_set_register(map, rbnode,
 454                                              reg - rbnode->base_reg, value);
 455                 regcache_rbtree_insert(map, &rbtree_ctx->root, rbnode);
 456                 rbtree_ctx->cached_rbnode = rbnode;
 457         }
 458
 459         return 0;
 460 }
 461
 462 static int regcache_rbtree_sync(struct regmap *map, unsigned int min,
 463                                 unsigned int max)
 464 {
 465         struct regcache_rbtree_ctx *rbtree_ctx;
 466         struct rb_node *node;
 467         struct regcache_rbtree_node *rbnode;
 468         unsigned int base_reg, top_reg;
 469         unsigned int start, end;
 470         int ret;
 471
 472         rbtree_ctx = map->cache;
 473         for (node = rb_first(&rbtree_ctx->root); node; node = rb_next(node)) {
 474                 rbnode = rb_entry(node, struct regcache_rbtree_node, node);
 475
 476                 regcache_rbtree_get_base_top_reg(map, rbnode, &base_reg,
 477                         &top_reg);
 478                 if (base_reg > max)
 479                         break;
 480                 if (top_reg < min)
 481                         continue;
 482
 483                 if (min > base_reg)
 484                         start = (min - base_reg) / map->reg_stride;
 485                 else
 486                         start = 0;
 487
 488                 if (max < top_reg)
 489                         end = (max - base_reg) / map->reg_stride + 1;
 490                 else
 491                         end = rbnode->blklen;
 492
 493                 ret = regcache_sync_block(map, rbnode->block,
 494                                           rbnode->cache_present,
 495                                           rbnode->base_reg, start, end);
 496                 if (ret != 0)
 497                         return ret;
 498         }
 499
 500         return regmap_async_complete(map);
 501 }
 502
 503 static int regcache_rbtree_drop(struct regmap *map, unsigned int min,
 504                                 unsigned int max)
 505 {
 506         struct regcache_rbtree_ctx *rbtree_ctx;
 507         struct regcache_rbtree_node *rbnode;
 508         struct rb_node *node;
 509         unsigned int base_reg, top_reg;
 510         unsigned int start, end;
 511
 512         rbtree_ctx = map->cache;
 513         for (node = rb_first(&rbtree_ctx->root); node; node = rb_next(node)) {
 514                 rbnode = rb_entry(node, struct regcache_rbtree_node, node);
 515
 516                 regcache_rbtree_get_base_top_reg(map, rbnode, &base_reg,
 517                         &top_reg);
 518                 if (base_reg > max)
 519                         break;
 520                 if (top_reg < min)
 521                         continue;
 522
 523                 if (min > base_reg)
 524                         start = (min - base_reg) / map->reg_stride;
 525                 else
 526                         start = 0;
 527
 528                 if (max < top_reg)
 529                         end = (max - base_reg) / map->reg_stride + 1;
 530                 else
 531                         end = rbnode->blklen;
 532
 533                 bitmap_clear(rbnode->cache_present, start, end - start);
 534         }
 535
 536         return 0;
 537 }
 538
 539 struct regcache_ops regcache_rbtree_ops = {
 540         .type = REGCACHE_RBTREE,
 541         .name = "rbtree",
 542         .init = regcache_rbtree_init,
 543         .exit = regcache_rbtree_exit,
 544 #ifdef CONFIG_DEBUG_FS
 545         .debugfs_init = rbtree_debugfs_init,
 546 #endif
 547         .read = regcache_rbtree_read,
 548         .write = regcache_rbtree_write,
 549         .sync = regcache_rbtree_sync,
 550         .drop = regcache_rbtree_drop,
 551 };