1 // SPDX-License-Identifier: GPL-2.0 2 // 3 // Register cache access API - rbtree caching support 4 // 5 // Copyright 2011 Wolfson Microelectronics plc 6 // 7 // Author: Dimitris Papastamos <dp@opensource.wolfsonmicro.com> 8 9 #include <linux/debugfs.h> 10 #include <linux/device.h> 11 #include <linux/rbtree.h> 12 #include <linux/seq_file.h> 13 #include <linux/slab.h> 14 15 #include "internal.h" 16 17 static int regcache_rbtree_write(struct regmap *map, unsigned int reg, 18 unsigned int value); 19 static int regcache_rbtree_exit(struct regmap *map); 20 21 struct regcache_rbtree_node { 22 /* block of adjacent registers */ 23 void *block; 24 /* Which registers are present */ 25 long *cache_present; 26 /* base register handled by this block */ 27 unsigned int base_reg; 28 /* number of registers available in the block */ 29 unsigned int blklen; 30 /* the actual rbtree node holding this block */ 31 struct rb_node node; 32 }; 33 34 struct regcache_rbtree_ctx { 35 struct rb_root root; 36 struct regcache_rbtree_node *cached_rbnode; 37 }; 38 39 static inline void regcache_rbtree_get_base_top_reg( 40 struct regmap *map, 41 struct regcache_rbtree_node *rbnode, 42 unsigned int *base, unsigned int *top) 43 { 44 *base = rbnode->base_reg; 45 *top = rbnode->base_reg + ((rbnode->blklen - 1) * map->reg_stride); 46 } 47 48 static unsigned int regcache_rbtree_get_register(struct regmap *map, 49 struct regcache_rbtree_node *rbnode, unsigned int idx) 50 { 51 return regcache_get_val(map, rbnode->block, idx); 52 } 53 54 static void regcache_rbtree_set_register(struct regmap *map, 55 struct regcache_rbtree_node *rbnode, 56 unsigned int idx, unsigned int val) 57 { 58 set_bit(idx, rbnode->cache_present); 59 regcache_set_val(map, rbnode->block, idx, val); 60 } 61 62 static struct regcache_rbtree_node *regcache_rbtree_lookup(struct regmap *map, 63 unsigned int reg) 64 { 65 struct regcache_rbtree_ctx *rbtree_ctx = map->cache; 66 struct rb_node *node; 67 struct regcache_rbtree_node *rbnode; 68 unsigned int base_reg, top_reg; 69 70 rbnode = rbtree_ctx->cached_rbnode; 71 if (rbnode) { 72 regcache_rbtree_get_base_top_reg(map, rbnode, &base_reg, 73 &top_reg); 74 if (reg >= base_reg && reg <= top_reg) 75 return rbnode; 76 } 77 78 node = rbtree_ctx->root.rb_node; 79 while (node) { 80 rbnode = rb_entry(node, struct regcache_rbtree_node, node); 81 regcache_rbtree_get_base_top_reg(map, rbnode, &base_reg, 82 &top_reg); 83 if (reg >= base_reg && reg <= top_reg) { 84 rbtree_ctx->cached_rbnode = rbnode; 85 return rbnode; 86 } else if (reg > top_reg) { 87 node = node->rb_right; 88 } else if (reg < base_reg) { 89 node = node->rb_left; 90 } 91 } 92 93 return NULL; 94 } 95 96 static int regcache_rbtree_insert(struct regmap *map, struct rb_root *root, 97 struct regcache_rbtree_node *rbnode) 98 { 99 struct rb_node **new, *parent; 100 struct regcache_rbtree_node *rbnode_tmp; 101 unsigned int base_reg_tmp, top_reg_tmp; 102 unsigned int base_reg; 103 104 parent = NULL; 105 new = &root->rb_node; 106 while (*new) { 107 rbnode_tmp = rb_entry(*new, struct regcache_rbtree_node, node); 108 /* base and top registers of the current rbnode */ 109 regcache_rbtree_get_base_top_reg(map, rbnode_tmp, &base_reg_tmp, 110 &top_reg_tmp); 111 /* base register of the rbnode to be added */ 112 base_reg = rbnode->base_reg; 113 parent = *new; 114 /* if this register has already been inserted, just return */ 115 if (base_reg >= base_reg_tmp && 116 base_reg <= top_reg_tmp) 117 return 0; 118 else if (base_reg > top_reg_tmp) 119 new = &((*new)->rb_right); 120 else if (base_reg < base_reg_tmp) 121 new = &((*new)->rb_left); 122 } 123 124 /* insert the node into the rbtree */ 125 rb_link_node(&rbnode->node, parent, new); 126 rb_insert_color(&rbnode->node, root); 127 128 return 1; 129 } 130 131 #ifdef CONFIG_DEBUG_FS 132 static int rbtree_show(struct seq_file *s, void *ignored) 133 { 134 struct regmap *map = s->private; 135 struct regcache_rbtree_ctx *rbtree_ctx = map->cache; 136 struct regcache_rbtree_node *n; 137 struct rb_node *node; 138 unsigned int base, top; 139 size_t mem_size; 140 int nodes = 0; 141 int registers = 0; 142 int this_registers, average; 143 144 map->lock(map->lock_arg); 145 146 mem_size = sizeof(*rbtree_ctx); 147 148 for (node = rb_first(&rbtree_ctx->root); node != NULL; 149 node = rb_next(node)) { 150 n = rb_entry(node, struct regcache_rbtree_node, node); 151 mem_size += sizeof(*n); 152 mem_size += (n->blklen * map->cache_word_size); 153 mem_size += BITS_TO_LONGS(n->blklen) * sizeof(long); 154 155 regcache_rbtree_get_base_top_reg(map, n, &base, &top); 156 this_registers = ((top - base) / map->reg_stride) + 1; 157 seq_printf(s, "%x-%x (%d)\n", base, top, this_registers); 158 159 nodes++; 160 registers += this_registers; 161 } 162 163 if (nodes) 164 average = registers / nodes; 165 else 166 average = 0; 167 168 seq_printf(s, "%d nodes, %d registers, average %d registers, used %zu bytes\n", 169 nodes, registers, average, mem_size); 170 171 map->unlock(map->lock_arg); 172 173 return 0; 174 } 175 176 DEFINE_SHOW_ATTRIBUTE(rbtree); 177 178 static void rbtree_debugfs_init(struct regmap *map) 179 { 180 debugfs_create_file("rbtree", 0400, map->debugfs, map, &rbtree_fops); 181 } 182 #endif 183 184 static int regcache_rbtree_init(struct regmap *map) 185 { 186 struct regcache_rbtree_ctx *rbtree_ctx; 187 int i; 188 int ret; 189 190 map->cache = kmalloc(sizeof *rbtree_ctx, GFP_KERNEL); 191 if (!map->cache) 192 return -ENOMEM; 193 194 rbtree_ctx = map->cache; 195 rbtree_ctx->root = RB_ROOT; 196 rbtree_ctx->cached_rbnode = NULL; 197 198 for (i = 0; i < map->num_reg_defaults; i++) { 199 ret = regcache_rbtree_write(map, 200 map->reg_defaults[i].reg, 201 map->reg_defaults[i].def); 202 if (ret) 203 goto err; 204 } 205 206 return 0; 207 208 err: 209 regcache_rbtree_exit(map); 210 return ret; 211 } 212 213 static int regcache_rbtree_exit(struct regmap *map) 214 { 215 struct rb_node *next; 216 struct regcache_rbtree_ctx *rbtree_ctx; 217 struct regcache_rbtree_node *rbtree_node; 218 219 /* if we've already been called then just return */ 220 rbtree_ctx = map->cache; 221 if (!rbtree_ctx) 222 return 0; 223 224 /* free up the rbtree */ 225 next = rb_first(&rbtree_ctx->root); 226 while (next) { 227 rbtree_node = rb_entry(next, struct regcache_rbtree_node, node); 228 next = rb_next(&rbtree_node->node); 229 rb_erase(&rbtree_node->node, &rbtree_ctx->root); 230 kfree(rbtree_node->cache_present); 231 kfree(rbtree_node->block); 232 kfree(rbtree_node); 233 } 234 235 /* release the resources */ 236 kfree(map->cache); 237 map->cache = NULL; 238 239 return 0; 240 } 241 242 static int regcache_rbtree_read(struct regmap *map, 243 unsigned int reg, unsigned int *value) 244 { 245 struct regcache_rbtree_node *rbnode; 246 unsigned int reg_tmp; 247 248 rbnode = regcache_rbtree_lookup(map, reg); 249 if (rbnode) { 250 reg_tmp = (reg - rbnode->base_reg) / map->reg_stride; 251 if (!test_bit(reg_tmp, rbnode->cache_present)) 252 return -ENOENT; 253 *value = regcache_rbtree_get_register(map, rbnode, reg_tmp); 254 } else { 255 return -ENOENT; 256 } 257 258 return 0; 259 } 260 261 262 static int regcache_rbtree_insert_to_block(struct regmap *map, 263 struct regcache_rbtree_node *rbnode, 264 unsigned int base_reg, 265 unsigned int top_reg, 266 unsigned int reg, 267 unsigned int value) 268 { 269 unsigned int blklen; 270 unsigned int pos, offset; 271 unsigned long *present; 272 u8 *blk; 273 274 blklen = (top_reg - base_reg) / map->reg_stride + 1; 275 pos = (reg - base_reg) / map->reg_stride; 276 offset = (rbnode->base_reg - base_reg) / map->reg_stride; 277 278 blk = krealloc(rbnode->block, 279 blklen * map->cache_word_size, 280 GFP_KERNEL); 281 if (!blk) 282 return -ENOMEM; 283 284 rbnode->block = blk; 285 286 if (BITS_TO_LONGS(blklen) > BITS_TO_LONGS(rbnode->blklen)) { 287 present = krealloc(rbnode->cache_present, 288 BITS_TO_LONGS(blklen) * sizeof(*present), 289 GFP_KERNEL); 290 if (!present) 291 return -ENOMEM; 292 293 memset(present + BITS_TO_LONGS(rbnode->blklen), 0, 294 (BITS_TO_LONGS(blklen) - BITS_TO_LONGS(rbnode->blklen)) 295 * sizeof(*present)); 296 } else { 297 present = rbnode->cache_present; 298 } 299 300 /* insert the register value in the correct place in the rbnode block */ 301 if (pos == 0) { 302 memmove(blk + offset * map->cache_word_size, 303 blk, rbnode->blklen * map->cache_word_size); 304 bitmap_shift_left(present, present, offset, blklen); 305 } 306 307 /* update the rbnode block, its size and the base register */ 308 rbnode->blklen = blklen; 309 rbnode->base_reg = base_reg; 310 rbnode->cache_present = present; 311 312 regcache_rbtree_set_register(map, rbnode, pos, value); 313 return 0; 314 } 315 316 static struct regcache_rbtree_node * 317 regcache_rbtree_node_alloc(struct regmap *map, unsigned int reg) 318 { 319 struct regcache_rbtree_node *rbnode; 320 const struct regmap_range *range; 321 int i; 322 323 rbnode = kzalloc(sizeof(*rbnode), GFP_KERNEL); 324 if (!rbnode) 325 return NULL; 326 327 /* If there is a read table then use it to guess at an allocation */ 328 if (map->rd_table) { 329 for (i = 0; i < map->rd_table->n_yes_ranges; i++) { 330 if (regmap_reg_in_range(reg, 331 &map->rd_table->yes_ranges[i])) 332 break; 333 } 334 335 if (i != map->rd_table->n_yes_ranges) { 336 range = &map->rd_table->yes_ranges[i]; 337 rbnode->blklen = (range->range_max - range->range_min) / 338 map->reg_stride + 1; 339 rbnode->base_reg = range->range_min; 340 } 341 } 342 343 if (!rbnode->blklen) { 344 rbnode->blklen = 1; 345 rbnode->base_reg = reg; 346 } 347 348 rbnode->block = kmalloc_array(rbnode->blklen, map->cache_word_size, 349 GFP_KERNEL); 350 if (!rbnode->block) 351 goto err_free; 352 353 rbnode->cache_present = kcalloc(BITS_TO_LONGS(rbnode->blklen), 354 sizeof(*rbnode->cache_present), 355 GFP_KERNEL); 356 if (!rbnode->cache_present) 357 goto err_free_block; 358 359 return rbnode; 360 361 err_free_block: 362 kfree(rbnode->block); 363 err_free: 364 kfree(rbnode); 365 return NULL; 366 } 367 368 static int regcache_rbtree_write(struct regmap *map, unsigned int reg, 369 unsigned int value) 370 { 371 struct regcache_rbtree_ctx *rbtree_ctx; 372 struct regcache_rbtree_node *rbnode, *rbnode_tmp; 373 struct rb_node *node; 374 unsigned int reg_tmp; 375 int ret; 376 377 rbtree_ctx = map->cache; 378 379 /* if we can't locate it in the cached rbnode we'll have 380 * to traverse the rbtree looking for it. 381 */ 382 rbnode = regcache_rbtree_lookup(map, reg); 383 if (rbnode) { 384 reg_tmp = (reg - rbnode->base_reg) / map->reg_stride; 385 regcache_rbtree_set_register(map, rbnode, reg_tmp, value); 386 } else { 387 unsigned int base_reg, top_reg; 388 unsigned int new_base_reg, new_top_reg; 389 unsigned int min, max; 390 unsigned int max_dist; 391 unsigned int dist, best_dist = UINT_MAX; 392 393 max_dist = map->reg_stride * sizeof(*rbnode_tmp) / 394 map->cache_word_size; 395 if (reg < max_dist) 396 min = 0; 397 else 398 min = reg - max_dist; 399 max = reg + max_dist; 400 401 /* look for an adjacent register to the one we are about to add */ 402 node = rbtree_ctx->root.rb_node; 403 while (node) { 404 rbnode_tmp = rb_entry(node, struct regcache_rbtree_node, 405 node); 406 407 regcache_rbtree_get_base_top_reg(map, rbnode_tmp, 408 &base_reg, &top_reg); 409 410 if (base_reg <= max && top_reg >= min) { 411 if (reg < base_reg) 412 dist = base_reg - reg; 413 else if (reg > top_reg) 414 dist = reg - top_reg; 415 else 416 dist = 0; 417 if (dist < best_dist) { 418 rbnode = rbnode_tmp; 419 best_dist = dist; 420 new_base_reg = min(reg, base_reg); 421 new_top_reg = max(reg, top_reg); 422 } 423 } 424 425 /* 426 * Keep looking, we want to choose the closest block, 427 * otherwise we might end up creating overlapping 428 * blocks, which breaks the rbtree. 429 */ 430 if (reg < base_reg) 431 node = node->rb_left; 432 else if (reg > top_reg) 433 node = node->rb_right; 434 else 435 break; 436 } 437 438 if (rbnode) { 439 ret = regcache_rbtree_insert_to_block(map, rbnode, 440 new_base_reg, 441 new_top_reg, reg, 442 value); 443 if (ret) 444 return ret; 445 rbtree_ctx->cached_rbnode = rbnode; 446 return 0; 447 } 448 449 /* We did not manage to find a place to insert it in 450 * an existing block so create a new rbnode. 451 */ 452 rbnode = regcache_rbtree_node_alloc(map, reg); 453 if (!rbnode) 454 return -ENOMEM; 455 regcache_rbtree_set_register(map, rbnode, 456 reg - rbnode->base_reg, value); 457 regcache_rbtree_insert(map, &rbtree_ctx->root, rbnode); 458 rbtree_ctx->cached_rbnode = rbnode; 459 } 460 461 return 0; 462 } 463 464 static int regcache_rbtree_sync(struct regmap *map, unsigned int min, 465 unsigned int max) 466 { 467 struct regcache_rbtree_ctx *rbtree_ctx; 468 struct rb_node *node; 469 struct regcache_rbtree_node *rbnode; 470 unsigned int base_reg, top_reg; 471 unsigned int start, end; 472 int ret; 473 474 map->async = true; 475 476 rbtree_ctx = map->cache; 477 for (node = rb_first(&rbtree_ctx->root); node; node = rb_next(node)) { 478 rbnode = rb_entry(node, struct regcache_rbtree_node, node); 479 480 regcache_rbtree_get_base_top_reg(map, rbnode, &base_reg, 481 &top_reg); 482 if (base_reg > max) 483 break; 484 if (top_reg < min) 485 continue; 486 487 if (min > base_reg) 488 start = (min - base_reg) / map->reg_stride; 489 else 490 start = 0; 491 492 if (max < top_reg) 493 end = (max - base_reg) / map->reg_stride + 1; 494 else 495 end = rbnode->blklen; 496 497 ret = regcache_sync_block(map, rbnode->block, 498 rbnode->cache_present, 499 rbnode->base_reg, start, end); 500 if (ret != 0) 501 return ret; 502 } 503 504 map->async = false; 505 506 return regmap_async_complete(map); 507 } 508 509 static int regcache_rbtree_drop(struct regmap *map, unsigned int min, 510 unsigned int max) 511 { 512 struct regcache_rbtree_ctx *rbtree_ctx; 513 struct regcache_rbtree_node *rbnode; 514 struct rb_node *node; 515 unsigned int base_reg, top_reg; 516 unsigned int start, end; 517 518 rbtree_ctx = map->cache; 519 for (node = rb_first(&rbtree_ctx->root); node; node = rb_next(node)) { 520 rbnode = rb_entry(node, struct regcache_rbtree_node, node); 521 522 regcache_rbtree_get_base_top_reg(map, rbnode, &base_reg, 523 &top_reg); 524 if (base_reg > max) 525 break; 526 if (top_reg < min) 527 continue; 528 529 if (min > base_reg) 530 start = (min - base_reg) / map->reg_stride; 531 else 532 start = 0; 533 534 if (max < top_reg) 535 end = (max - base_reg) / map->reg_stride + 1; 536 else 537 end = rbnode->blklen; 538 539 bitmap_clear(rbnode->cache_present, start, end - start); 540 } 541 542 return 0; 543 } 544 545 struct regcache_ops regcache_rbtree_ops = { 546 .type = REGCACHE_RBTREE, 547 .name = "rbtree", 548 .init = regcache_rbtree_init, 549 .exit = regcache_rbtree_exit, 550 #ifdef CONFIG_DEBUG_FS 551 .debugfs_init = rbtree_debugfs_init, 552 #endif 553 .read = regcache_rbtree_read, 554 .write = regcache_rbtree_write, 555 .sync = regcache_rbtree_sync, 556 .drop = regcache_rbtree_drop, 557 }; 558