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 /* 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 36 struct regcache_rbtree_ctx { 37 struct rb_root root; 38 struct regcache_rbtree_node *cached_rbnode; 39 }; 40 41 static 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 50 static 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 56 static 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 63 static 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 97 static 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 134 static 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 mem_size += BITS_TO_LONGS(map->cache_present_nbits) * sizeof(long); 150 151 for (node = rb_first(&rbtree_ctx->root); node != NULL; 152 node = rb_next(node)) { 153 n = container_of(node, struct regcache_rbtree_node, node); 154 mem_size += sizeof(*n); 155 mem_size += (n->blklen * map->cache_word_size); 156 157 regcache_rbtree_get_base_top_reg(map, n, &base, &top); 158 this_registers = ((top - base) / map->reg_stride) + 1; 159 seq_printf(s, "%x-%x (%d)\n", base, top, this_registers); 160 161 nodes++; 162 registers += this_registers; 163 } 164 165 if (nodes) 166 average = registers / nodes; 167 else 168 average = 0; 169 170 seq_printf(s, "%d nodes, %d registers, average %d registers, used %zu bytes\n", 171 nodes, registers, average, mem_size); 172 173 map->unlock(map); 174 175 return 0; 176 } 177 178 static int rbtree_open(struct inode *inode, struct file *file) 179 { 180 return single_open(file, rbtree_show, inode->i_private); 181 } 182 183 static const struct file_operations rbtree_fops = { 184 .open = rbtree_open, 185 .read = seq_read, 186 .llseek = seq_lseek, 187 .release = single_release, 188 }; 189 190 static void rbtree_debugfs_init(struct regmap *map) 191 { 192 debugfs_create_file("rbtree", 0400, map->debugfs, map, &rbtree_fops); 193 } 194 #else 195 static void rbtree_debugfs_init(struct regmap *map) 196 { 197 } 198 #endif 199 200 static int regcache_rbtree_init(struct regmap *map) 201 { 202 struct regcache_rbtree_ctx *rbtree_ctx; 203 int i; 204 int ret; 205 206 map->cache = kmalloc(sizeof *rbtree_ctx, GFP_KERNEL); 207 if (!map->cache) 208 return -ENOMEM; 209 210 rbtree_ctx = map->cache; 211 rbtree_ctx->root = RB_ROOT; 212 rbtree_ctx->cached_rbnode = NULL; 213 214 for (i = 0; i < map->num_reg_defaults; i++) { 215 ret = regcache_rbtree_write(map, 216 map->reg_defaults[i].reg, 217 map->reg_defaults[i].def); 218 if (ret) 219 goto err; 220 } 221 222 rbtree_debugfs_init(map); 223 224 return 0; 225 226 err: 227 regcache_rbtree_exit(map); 228 return ret; 229 } 230 231 static int regcache_rbtree_exit(struct regmap *map) 232 { 233 struct rb_node *next; 234 struct regcache_rbtree_ctx *rbtree_ctx; 235 struct regcache_rbtree_node *rbtree_node; 236 237 /* if we've already been called then just return */ 238 rbtree_ctx = map->cache; 239 if (!rbtree_ctx) 240 return 0; 241 242 /* free up the rbtree */ 243 next = rb_first(&rbtree_ctx->root); 244 while (next) { 245 rbtree_node = rb_entry(next, struct regcache_rbtree_node, node); 246 next = rb_next(&rbtree_node->node); 247 rb_erase(&rbtree_node->node, &rbtree_ctx->root); 248 kfree(rbtree_node->block); 249 kfree(rbtree_node); 250 } 251 252 /* release the resources */ 253 kfree(map->cache); 254 map->cache = NULL; 255 256 return 0; 257 } 258 259 static int regcache_rbtree_read(struct regmap *map, 260 unsigned int reg, unsigned int *value) 261 { 262 struct regcache_rbtree_node *rbnode; 263 unsigned int reg_tmp; 264 265 rbnode = regcache_rbtree_lookup(map, reg); 266 if (rbnode) { 267 reg_tmp = (reg - rbnode->base_reg) / map->reg_stride; 268 if (!regcache_reg_present(map, reg)) 269 return -ENOENT; 270 *value = regcache_rbtree_get_register(map, rbnode, reg_tmp); 271 } else { 272 return -ENOENT; 273 } 274 275 return 0; 276 } 277 278 279 static int regcache_rbtree_insert_to_block(struct regmap *map, 280 struct regcache_rbtree_node *rbnode, 281 unsigned int pos, unsigned int reg, 282 unsigned int value) 283 { 284 u8 *blk; 285 286 blk = krealloc(rbnode->block, 287 (rbnode->blklen + 1) * map->cache_word_size, 288 GFP_KERNEL); 289 if (!blk) 290 return -ENOMEM; 291 292 /* insert the register value in the correct place in the rbnode block */ 293 memmove(blk + (pos + 1) * map->cache_word_size, 294 blk + pos * map->cache_word_size, 295 (rbnode->blklen - pos) * map->cache_word_size); 296 297 /* update the rbnode block, its size and the base register */ 298 rbnode->block = blk; 299 rbnode->blklen++; 300 if (!pos) 301 rbnode->base_reg = reg; 302 303 regcache_rbtree_set_register(map, rbnode, pos, value); 304 return 0; 305 } 306 307 static int regcache_rbtree_write(struct regmap *map, unsigned int reg, 308 unsigned int value) 309 { 310 struct regcache_rbtree_ctx *rbtree_ctx; 311 struct regcache_rbtree_node *rbnode, *rbnode_tmp; 312 struct rb_node *node; 313 unsigned int reg_tmp; 314 unsigned int pos; 315 int i; 316 int ret; 317 318 rbtree_ctx = map->cache; 319 /* update the reg_present bitmap, make space if necessary */ 320 ret = regcache_set_reg_present(map, reg); 321 if (ret < 0) 322 return ret; 323 324 /* if we can't locate it in the cached rbnode we'll have 325 * to traverse the rbtree looking for it. 326 */ 327 rbnode = regcache_rbtree_lookup(map, reg); 328 if (rbnode) { 329 reg_tmp = (reg - rbnode->base_reg) / map->reg_stride; 330 regcache_rbtree_set_register(map, rbnode, reg_tmp, value); 331 } else { 332 /* look for an adjacent register to the one we are about to add */ 333 for (node = rb_first(&rbtree_ctx->root); node; 334 node = rb_next(node)) { 335 rbnode_tmp = rb_entry(node, struct regcache_rbtree_node, 336 node); 337 for (i = 0; i < rbnode_tmp->blklen; i++) { 338 reg_tmp = rbnode_tmp->base_reg + 339 (i * map->reg_stride); 340 if (abs(reg_tmp - reg) != map->reg_stride) 341 continue; 342 /* decide where in the block to place our register */ 343 if (reg_tmp + map->reg_stride == reg) 344 pos = i + 1; 345 else 346 pos = i; 347 ret = regcache_rbtree_insert_to_block(map, 348 rbnode_tmp, 349 pos, reg, 350 value); 351 if (ret) 352 return ret; 353 rbtree_ctx->cached_rbnode = rbnode_tmp; 354 return 0; 355 } 356 } 357 /* we did not manage to find a place to insert it in an existing 358 * block so create a new rbnode with a single register in its block. 359 * This block will get populated further if any other adjacent 360 * registers get modified in the future. 361 */ 362 rbnode = kzalloc(sizeof *rbnode, GFP_KERNEL); 363 if (!rbnode) 364 return -ENOMEM; 365 rbnode->blklen = sizeof(*rbnode); 366 rbnode->base_reg = reg; 367 rbnode->block = kmalloc(rbnode->blklen * map->cache_word_size, 368 GFP_KERNEL); 369 if (!rbnode->block) { 370 kfree(rbnode); 371 return -ENOMEM; 372 } 373 regcache_rbtree_set_register(map, rbnode, 0, value); 374 regcache_rbtree_insert(map, &rbtree_ctx->root, rbnode); 375 rbtree_ctx->cached_rbnode = rbnode; 376 } 377 378 return 0; 379 } 380 381 static int regcache_rbtree_sync(struct regmap *map, unsigned int min, 382 unsigned int max) 383 { 384 struct regcache_rbtree_ctx *rbtree_ctx; 385 struct rb_node *node; 386 struct regcache_rbtree_node *rbnode; 387 int ret; 388 int base, end; 389 390 rbtree_ctx = map->cache; 391 for (node = rb_first(&rbtree_ctx->root); node; node = rb_next(node)) { 392 rbnode = rb_entry(node, struct regcache_rbtree_node, node); 393 394 if (rbnode->base_reg < min) 395 continue; 396 if (rbnode->base_reg > max) 397 break; 398 if (rbnode->base_reg + rbnode->blklen < min) 399 continue; 400 401 if (min > rbnode->base_reg) 402 base = min - rbnode->base_reg; 403 else 404 base = 0; 405 406 if (max < rbnode->base_reg + rbnode->blklen) 407 end = max - rbnode->base_reg + 1; 408 else 409 end = rbnode->blklen; 410 411 ret = regcache_sync_block(map, rbnode->block, rbnode->base_reg, 412 base, end); 413 if (ret != 0) 414 return ret; 415 } 416 417 return regmap_async_complete(map); 418 } 419 420 struct regcache_ops regcache_rbtree_ops = { 421 .type = REGCACHE_RBTREE, 422 .name = "rbtree", 423 .init = regcache_rbtree_init, 424 .exit = regcache_rbtree_exit, 425 .read = regcache_rbtree_read, 426 .write = regcache_rbtree_write, 427 .sync = regcache_rbtree_sync 428 }; 429