2 * Register cache access API - rbtree caching support
4 * Copyright 2011 Wolfson Microelectronics plc
6 * Author: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
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.
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>
21 static int regcache_rbtree_write(struct regmap *map, unsigned int reg,
23 static int regcache_rbtree_exit(struct regmap *map);
25 struct regcache_rbtree_node {
26 /* the actual rbtree node holding this block */
28 /* base register handled by this block */
29 unsigned int base_reg;
30 /* block of adjacent registers */
32 /* number of registers available in the block */
34 } __attribute__ ((packed));
36 struct regcache_rbtree_ctx {
38 struct regcache_rbtree_node *cached_rbnode;
41 static inline void regcache_rbtree_get_base_top_reg(
43 struct regcache_rbtree_node *rbnode,
44 unsigned int *base, unsigned int *top)
46 *base = rbnode->base_reg;
47 *top = rbnode->base_reg + ((rbnode->blklen - 1) * map->reg_stride);
50 static unsigned int regcache_rbtree_get_register(struct regmap *map,
51 struct regcache_rbtree_node *rbnode, unsigned int idx)
53 return regcache_get_val(map, rbnode->block, idx);
56 static void regcache_rbtree_set_register(struct regmap *map,
57 struct regcache_rbtree_node *rbnode,
58 unsigned int idx, unsigned int val)
60 regcache_set_val(map, rbnode->block, idx, val);
63 static struct regcache_rbtree_node *regcache_rbtree_lookup(struct regmap *map,
66 struct regcache_rbtree_ctx *rbtree_ctx = map->cache;
68 struct regcache_rbtree_node *rbnode;
69 unsigned int base_reg, top_reg;
71 rbnode = rbtree_ctx->cached_rbnode;
73 regcache_rbtree_get_base_top_reg(map, rbnode, &base_reg,
75 if (reg >= base_reg && reg <= top_reg)
79 node = rbtree_ctx->root.rb_node;
81 rbnode = container_of(node, struct regcache_rbtree_node, node);
82 regcache_rbtree_get_base_top_reg(map, rbnode, &base_reg,
84 if (reg >= base_reg && reg <= top_reg) {
85 rbtree_ctx->cached_rbnode = rbnode;
87 } else if (reg > top_reg) {
88 node = node->rb_right;
89 } else if (reg < base_reg) {
97 static int regcache_rbtree_insert(struct regmap *map, struct rb_root *root,
98 struct regcache_rbtree_node *rbnode)
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;
106 new = &root->rb_node;
108 rbnode_tmp = container_of(*new, struct regcache_rbtree_node,
110 /* base and top registers of the current rbnode */
111 regcache_rbtree_get_base_top_reg(map, rbnode_tmp, &base_reg_tmp,
113 /* base register of the rbnode to be added */
114 base_reg = rbnode->base_reg;
116 /* if this register has already been inserted, just return */
117 if (base_reg >= base_reg_tmp &&
118 base_reg <= top_reg_tmp)
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);
126 /* insert the node into the rbtree */
127 rb_link_node(&rbnode->node, parent, new);
128 rb_insert_color(&rbnode->node, root);
133 #ifdef CONFIG_DEBUG_FS
134 static int rbtree_show(struct seq_file *s, void *ignored)
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;
144 int this_registers, average;
148 mem_size = sizeof(*rbtree_ctx);
149 mem_size += BITS_TO_LONGS(map->cache_present_nbits) * sizeof(long);
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);
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);
162 registers += this_registers;
166 average = registers / nodes;
170 seq_printf(s, "%d nodes, %d registers, average %d registers, used %zu bytes\n",
171 nodes, registers, average, mem_size);
178 static int rbtree_open(struct inode *inode, struct file *file)
180 return single_open(file, rbtree_show, inode->i_private);
183 static const struct file_operations rbtree_fops = {
187 .release = single_release,
190 static void rbtree_debugfs_init(struct regmap *map)
192 debugfs_create_file("rbtree", 0400, map->debugfs, map, &rbtree_fops);
195 static void rbtree_debugfs_init(struct regmap *map)
200 static int regcache_rbtree_init(struct regmap *map)
202 struct regcache_rbtree_ctx *rbtree_ctx;
206 map->cache = kmalloc(sizeof *rbtree_ctx, GFP_KERNEL);
210 rbtree_ctx = map->cache;
211 rbtree_ctx->root = RB_ROOT;
212 rbtree_ctx->cached_rbnode = NULL;
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);
222 rbtree_debugfs_init(map);
227 regcache_rbtree_exit(map);
231 static int regcache_rbtree_exit(struct regmap *map)
233 struct rb_node *next;
234 struct regcache_rbtree_ctx *rbtree_ctx;
235 struct regcache_rbtree_node *rbtree_node;
237 /* if we've already been called then just return */
238 rbtree_ctx = map->cache;
242 /* free up the rbtree */
243 next = rb_first(&rbtree_ctx->root);
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);
252 /* release the resources */
259 static int regcache_rbtree_read(struct regmap *map,
260 unsigned int reg, unsigned int *value)
262 struct regcache_rbtree_node *rbnode;
263 unsigned int reg_tmp;
265 rbnode = regcache_rbtree_lookup(map, reg);
267 reg_tmp = (reg - rbnode->base_reg) / map->reg_stride;
268 if (!regcache_reg_present(map, reg))
270 *value = regcache_rbtree_get_register(map, rbnode, reg_tmp);
279 static int regcache_rbtree_insert_to_block(struct regmap *map,
280 struct regcache_rbtree_node *rbnode,
281 unsigned int pos, unsigned int reg,
286 blk = krealloc(rbnode->block,
287 (rbnode->blklen + 1) * map->cache_word_size,
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);
297 /* update the rbnode block, its size and the base register */
301 rbnode->base_reg = reg;
303 regcache_rbtree_set_register(map, rbnode, pos, value);
307 static int regcache_rbtree_write(struct regmap *map, unsigned int reg,
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;
318 rbtree_ctx = map->cache;
319 /* update the reg_present bitmap, make space if necessary */
320 ret = regcache_set_reg_present(map, reg);
324 /* if we can't locate it in the cached rbnode we'll have
325 * to traverse the rbtree looking for it.
327 rbnode = regcache_rbtree_lookup(map, reg);
329 reg_tmp = (reg - rbnode->base_reg) / map->reg_stride;
330 regcache_rbtree_set_register(map, rbnode, reg_tmp, value);
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,
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)
342 /* decide where in the block to place our register */
343 if (reg_tmp + map->reg_stride == reg)
347 ret = regcache_rbtree_insert_to_block(map,
353 rbtree_ctx->cached_rbnode = rbnode_tmp;
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.
362 rbnode = kzalloc(sizeof *rbnode, GFP_KERNEL);
365 rbnode->blklen = sizeof(*rbnode);
366 rbnode->base_reg = reg;
367 rbnode->block = kmalloc(rbnode->blklen * map->cache_word_size,
369 if (!rbnode->block) {
373 regcache_rbtree_set_register(map, rbnode, 0, value);
374 regcache_rbtree_insert(map, &rbtree_ctx->root, rbnode);
375 rbtree_ctx->cached_rbnode = rbnode;
381 static int regcache_rbtree_sync(struct regmap *map, unsigned int min,
384 struct regcache_rbtree_ctx *rbtree_ctx;
385 struct rb_node *node;
386 struct regcache_rbtree_node *rbnode;
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);
394 if (rbnode->base_reg < min)
396 if (rbnode->base_reg > max)
398 if (rbnode->base_reg + rbnode->blklen < min)
401 if (min > rbnode->base_reg)
402 base = min - rbnode->base_reg;
406 if (max < rbnode->base_reg + rbnode->blklen)
407 end = max - rbnode->base_reg + 1;
409 end = rbnode->blklen;
411 ret = regcache_sync_block(map, rbnode->block, rbnode->base_reg,
417 return regmap_async_complete(map);
420 struct regcache_ops regcache_rbtree_ops = {
421 .type = REGCACHE_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