regcache-rbtree.c revision a42277c739c29b06cb27502347f557e11fed8b0e
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 21static int regcache_rbtree_write(struct regmap *map, unsigned int reg, 22 unsigned int value); 23static int regcache_rbtree_exit(struct regmap *map); 24 25struct regcache_rbtree_node { 26 /* the actual rbtree node holding this block */ 27 struct rb_node node; 28 /* base register handled by this block */ 29 unsigned int base_reg; 30 /* block of adjacent registers */ 31 void *block; 32 /* number of registers available in the block */ 33 unsigned int blklen; 34} __attribute__ ((packed)); 35 36struct regcache_rbtree_ctx { 37 struct rb_root root; 38 struct regcache_rbtree_node *cached_rbnode; 39}; 40 41static inline void regcache_rbtree_get_base_top_reg( 42 struct regmap *map, 43 struct regcache_rbtree_node *rbnode, 44 unsigned int *base, unsigned int *top) 45{ 46 *base = rbnode->base_reg; 47 *top = rbnode->base_reg + ((rbnode->blklen - 1) * map->reg_stride); 48} 49 50static unsigned int regcache_rbtree_get_register(struct regmap *map, 51 struct regcache_rbtree_node *rbnode, unsigned int idx) 52{ 53 return regcache_get_val(map, rbnode->block, idx); 54} 55 56static void regcache_rbtree_set_register(struct regmap *map, 57 struct regcache_rbtree_node *rbnode, 58 unsigned int idx, unsigned int val) 59{ 60 regcache_set_val(map, rbnode->block, idx, val); 61} 62 63static struct regcache_rbtree_node *regcache_rbtree_lookup(struct regmap *map, 64 unsigned int reg) 65{ 66 struct regcache_rbtree_ctx *rbtree_ctx = map->cache; 67 struct rb_node *node; 68 struct regcache_rbtree_node *rbnode; 69 unsigned int base_reg, top_reg; 70 71 rbnode = rbtree_ctx->cached_rbnode; 72 if (rbnode) { 73 regcache_rbtree_get_base_top_reg(map, rbnode, &base_reg, 74 &top_reg); 75 if (reg >= base_reg && reg <= top_reg) 76 return rbnode; 77 } 78 79 node = rbtree_ctx->root.rb_node; 80 while (node) { 81 rbnode = container_of(node, struct regcache_rbtree_node, node); 82 regcache_rbtree_get_base_top_reg(map, rbnode, &base_reg, 83 &top_reg); 84 if (reg >= base_reg && reg <= top_reg) { 85 rbtree_ctx->cached_rbnode = rbnode; 86 return rbnode; 87 } else if (reg > top_reg) { 88 node = node->rb_right; 89 } else if (reg < base_reg) { 90 node = node->rb_left; 91 } 92 } 93 94 return NULL; 95} 96 97static int regcache_rbtree_insert(struct regmap *map, struct rb_root *root, 98 struct regcache_rbtree_node *rbnode) 99{ 100 struct rb_node **new, *parent; 101 struct regcache_rbtree_node *rbnode_tmp; 102 unsigned int base_reg_tmp, top_reg_tmp; 103 unsigned int base_reg; 104 105 parent = NULL; 106 new = &root->rb_node; 107 while (*new) { 108 rbnode_tmp = container_of(*new, struct regcache_rbtree_node, 109 node); 110 /* base and top registers of the current rbnode */ 111 regcache_rbtree_get_base_top_reg(map, rbnode_tmp, &base_reg_tmp, 112 &top_reg_tmp); 113 /* base register of the rbnode to be added */ 114 base_reg = rbnode->base_reg; 115 parent = *new; 116 /* if this register has already been inserted, just return */ 117 if (base_reg >= base_reg_tmp && 118 base_reg <= top_reg_tmp) 119 return 0; 120 else if (base_reg > top_reg_tmp) 121 new = &((*new)->rb_right); 122 else if (base_reg < base_reg_tmp) 123 new = &((*new)->rb_left); 124 } 125 126 /* insert the node into the rbtree */ 127 rb_link_node(&rbnode->node, parent, new); 128 rb_insert_color(&rbnode->node, root); 129 130 return 1; 131} 132 133#ifdef CONFIG_DEBUG_FS 134static int rbtree_show(struct seq_file *s, void *ignored) 135{ 136 struct regmap *map = s->private; 137 struct regcache_rbtree_ctx *rbtree_ctx = map->cache; 138 struct regcache_rbtree_node *n; 139 struct rb_node *node; 140 unsigned int base, top; 141 size_t mem_size; 142 int nodes = 0; 143 int registers = 0; 144 int this_registers, average; 145 146 map->lock(map); 147 148 mem_size = sizeof(*rbtree_ctx); 149 150 for (node = rb_first(&rbtree_ctx->root); node != NULL; 151 node = rb_next(node)) { 152 n = container_of(node, struct regcache_rbtree_node, node); 153 mem_size += sizeof(*n); 154 mem_size += (n->blklen * map->cache_word_size); 155 156 regcache_rbtree_get_base_top_reg(map, n, &base, &top); 157 this_registers = ((top - base) / map->reg_stride) + 1; 158 seq_printf(s, "%x-%x (%d)\n", base, top, this_registers); 159 160 nodes++; 161 registers += this_registers; 162 } 163 164 if (nodes) 165 average = registers / nodes; 166 else 167 average = 0; 168 169 seq_printf(s, "%d nodes, %d registers, average %d registers, used %zu bytes\n", 170 nodes, registers, average, mem_size); 171 172 map->unlock(map); 173 174 return 0; 175} 176 177static int rbtree_open(struct inode *inode, struct file *file) 178{ 179 return single_open(file, rbtree_show, inode->i_private); 180} 181 182static const struct file_operations rbtree_fops = { 183 .open = rbtree_open, 184 .read = seq_read, 185 .llseek = seq_lseek, 186 .release = single_release, 187}; 188 189static void rbtree_debugfs_init(struct regmap *map) 190{ 191 debugfs_create_file("rbtree", 0400, map->debugfs, map, &rbtree_fops); 192} 193#else 194static void rbtree_debugfs_init(struct regmap *map) 195{ 196} 197#endif 198 199static 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 rbtree_debugfs_init(map); 222 223 return 0; 224 225err: 226 regcache_rbtree_exit(map); 227 return ret; 228} 229 230static int regcache_rbtree_exit(struct regmap *map) 231{ 232 struct rb_node *next; 233 struct regcache_rbtree_ctx *rbtree_ctx; 234 struct regcache_rbtree_node *rbtree_node; 235 236 /* if we've already been called then just return */ 237 rbtree_ctx = map->cache; 238 if (!rbtree_ctx) 239 return 0; 240 241 /* free up the rbtree */ 242 next = rb_first(&rbtree_ctx->root); 243 while (next) { 244 rbtree_node = rb_entry(next, struct regcache_rbtree_node, node); 245 next = rb_next(&rbtree_node->node); 246 rb_erase(&rbtree_node->node, &rbtree_ctx->root); 247 kfree(rbtree_node->block); 248 kfree(rbtree_node); 249 } 250 251 /* release the resources */ 252 kfree(map->cache); 253 map->cache = NULL; 254 255 return 0; 256} 257 258static int regcache_rbtree_read(struct regmap *map, 259 unsigned int reg, unsigned int *value) 260{ 261 struct regcache_rbtree_node *rbnode; 262 unsigned int reg_tmp; 263 264 rbnode = regcache_rbtree_lookup(map, reg); 265 if (rbnode) { 266 reg_tmp = (reg - rbnode->base_reg) / map->reg_stride; 267 *value = regcache_rbtree_get_register(map, rbnode, reg_tmp); 268 } else { 269 return -ENOENT; 270 } 271 272 return 0; 273} 274 275 276static int regcache_rbtree_insert_to_block(struct regmap *map, 277 struct regcache_rbtree_node *rbnode, 278 unsigned int pos, unsigned int reg, 279 unsigned int value) 280{ 281 u8 *blk; 282 283 blk = krealloc(rbnode->block, 284 (rbnode->blklen + 1) * map->cache_word_size, 285 GFP_KERNEL); 286 if (!blk) 287 return -ENOMEM; 288 289 /* insert the register value in the correct place in the rbnode block */ 290 memmove(blk + (pos + 1) * map->cache_word_size, 291 blk + pos * map->cache_word_size, 292 (rbnode->blklen - pos) * map->cache_word_size); 293 294 /* update the rbnode block, its size and the base register */ 295 rbnode->block = blk; 296 rbnode->blklen++; 297 if (!pos) 298 rbnode->base_reg = reg; 299 300 regcache_rbtree_set_register(map, rbnode, pos, value); 301 return 0; 302} 303 304static int regcache_rbtree_write(struct regmap *map, unsigned int reg, 305 unsigned int value) 306{ 307 struct regcache_rbtree_ctx *rbtree_ctx; 308 struct regcache_rbtree_node *rbnode, *rbnode_tmp; 309 struct rb_node *node; 310 unsigned int reg_tmp; 311 unsigned int pos; 312 int i; 313 int ret; 314 315 rbtree_ctx = map->cache; 316 /* if we can't locate it in the cached rbnode we'll have 317 * to traverse the rbtree looking for it. 318 */ 319 rbnode = regcache_rbtree_lookup(map, reg); 320 if (rbnode) { 321 reg_tmp = (reg - rbnode->base_reg) / map->reg_stride; 322 regcache_rbtree_set_register(map, rbnode, reg_tmp, value); 323 } else { 324 /* look for an adjacent register to the one we are about to add */ 325 for (node = rb_first(&rbtree_ctx->root); node; 326 node = rb_next(node)) { 327 rbnode_tmp = rb_entry(node, struct regcache_rbtree_node, 328 node); 329 for (i = 0; i < rbnode_tmp->blklen; i++) { 330 reg_tmp = rbnode_tmp->base_reg + 331 (i * map->reg_stride); 332 if (abs(reg_tmp - reg) != map->reg_stride) 333 continue; 334 /* decide where in the block to place our register */ 335 if (reg_tmp + map->reg_stride == reg) 336 pos = i + 1; 337 else 338 pos = i; 339 ret = regcache_rbtree_insert_to_block(map, 340 rbnode_tmp, 341 pos, reg, 342 value); 343 if (ret) 344 return ret; 345 rbtree_ctx->cached_rbnode = rbnode_tmp; 346 return 0; 347 } 348 } 349 /* we did not manage to find a place to insert it in an existing 350 * block so create a new rbnode with a single register in its block. 351 * This block will get populated further if any other adjacent 352 * registers get modified in the future. 353 */ 354 rbnode = kzalloc(sizeof *rbnode, GFP_KERNEL); 355 if (!rbnode) 356 return -ENOMEM; 357 rbnode->blklen = 1; 358 rbnode->base_reg = reg; 359 rbnode->block = kmalloc(rbnode->blklen * map->cache_word_size, 360 GFP_KERNEL); 361 if (!rbnode->block) { 362 kfree(rbnode); 363 return -ENOMEM; 364 } 365 regcache_rbtree_set_register(map, rbnode, 0, value); 366 regcache_rbtree_insert(map, &rbtree_ctx->root, rbnode); 367 rbtree_ctx->cached_rbnode = rbnode; 368 } 369 370 return 0; 371} 372 373static int regcache_rbtree_sync(struct regmap *map, unsigned int min, 374 unsigned int max) 375{ 376 struct regcache_rbtree_ctx *rbtree_ctx; 377 struct rb_node *node; 378 struct regcache_rbtree_node *rbnode; 379 unsigned int regtmp; 380 unsigned int val; 381 int ret; 382 int i, base, end; 383 384 rbtree_ctx = map->cache; 385 for (node = rb_first(&rbtree_ctx->root); node; node = rb_next(node)) { 386 rbnode = rb_entry(node, struct regcache_rbtree_node, node); 387 388 if (rbnode->base_reg < min) 389 continue; 390 if (rbnode->base_reg > max) 391 break; 392 if (rbnode->base_reg + rbnode->blklen < min) 393 continue; 394 395 if (min > rbnode->base_reg) 396 base = min - rbnode->base_reg; 397 else 398 base = 0; 399 400 if (max < rbnode->base_reg + rbnode->blklen) 401 end = rbnode->base_reg + rbnode->blklen - max; 402 else 403 end = rbnode->blklen; 404 405 for (i = base; i < end; i++) { 406 regtmp = rbnode->base_reg + (i * map->reg_stride); 407 val = regcache_rbtree_get_register(map, rbnode, i); 408 409 /* Is this the hardware default? If so skip. */ 410 ret = regcache_lookup_reg(map, regtmp); 411 if (ret >= 0 && val == map->reg_defaults[ret].def) 412 continue; 413 414 map->cache_bypass = 1; 415 ret = _regmap_write(map, regtmp, val); 416 map->cache_bypass = 0; 417 if (ret) 418 return ret; 419 dev_dbg(map->dev, "Synced register %#x, value %#x\n", 420 regtmp, val); 421 } 422 } 423 424 return 0; 425} 426 427struct regcache_ops regcache_rbtree_ops = { 428 .type = REGCACHE_RBTREE, 429 .name = "rbtree", 430 .init = regcache_rbtree_init, 431 .exit = regcache_rbtree_exit, 432 .read = regcache_rbtree_read, 433 .write = regcache_rbtree_write, 434 .sync = regcache_rbtree_sync 435}; 436