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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(
51 struct regcache_rbtree_node *rbnode, unsigned int idx,
52 unsigned int word_size)
53{
54 return regcache_get_val(rbnode->block, idx, word_size);
55}
56
57static void regcache_rbtree_set_register(struct regcache_rbtree_node *rbnode,
58 unsigned int idx, unsigned int val,
59 unsigned int word_size)
60{
61 regcache_set_val(rbnode->block, idx, val, word_size);
62}
63
64static struct regcache_rbtree_node *regcache_rbtree_lookup(struct regmap *map,
65 unsigned int reg)
66{
67 struct regcache_rbtree_ctx *rbtree_ctx = map->cache;
68 struct rb_node *node;
69 struct regcache_rbtree_node *rbnode;
70 unsigned int base_reg, top_reg;
71
72 rbnode = rbtree_ctx->cached_rbnode;
73 if (rbnode) {
74 regcache_rbtree_get_base_top_reg(map, rbnode, &base_reg,
75 &top_reg);
76 if (reg >= base_reg && reg <= top_reg)
77 return rbnode;
78 }
79
80 node = rbtree_ctx->root.rb_node;
81 while (node) {
82 rbnode = container_of(node, struct regcache_rbtree_node, node);
83 regcache_rbtree_get_base_top_reg(map, rbnode, &base_reg,
84 &top_reg);
85 if (reg >= base_reg && reg <= top_reg) {
86 rbtree_ctx->cached_rbnode = rbnode;
87 return rbnode;
88 } else if (reg > top_reg) {
89 node = node->rb_right;
90 } else if (reg < base_reg) {
91 node = node->rb_left;
92 }
93 }
94
95 return NULL;
96}
97
98static int regcache_rbtree_insert(struct regmap *map, struct rb_root *root,
99 struct regcache_rbtree_node *rbnode)
100{
101 struct rb_node **new, *parent;
102 struct regcache_rbtree_node *rbnode_tmp;
103 unsigned int base_reg_tmp, top_reg_tmp;
104 unsigned int base_reg;
105
106 parent = NULL;
107 new = &root->rb_node;
108 while (*new) {
109 rbnode_tmp = container_of(*new, struct regcache_rbtree_node,
110 node);
111 /* base and top registers of the current rbnode */
112 regcache_rbtree_get_base_top_reg(map, rbnode_tmp, &base_reg_tmp,
113 &top_reg_tmp);
114 /* base register of the rbnode to be added */
115 base_reg = rbnode->base_reg;
116 parent = *new;
117 /* if this register has already been inserted, just return */
118 if (base_reg >= base_reg_tmp &&
119 base_reg <= top_reg_tmp)
120 return 0;
121 else if (base_reg > top_reg_tmp)
122 new = &((*new)->rb_right);
123 else if (base_reg < base_reg_tmp)
124 new = &((*new)->rb_left);
125 }
126
127 /* insert the node into the rbtree */
128 rb_link_node(&rbnode->node, parent, new);
129 rb_insert_color(&rbnode->node, root);
130
131 return 1;
132}
133
134#ifdef CONFIG_DEBUG_FS
135static int rbtree_show(struct seq_file *s, void *ignored)
136{
137 struct regmap *map = s->private;
138 struct regcache_rbtree_ctx *rbtree_ctx = map->cache;
139 struct regcache_rbtree_node *n;
140 struct rb_node *node;
141 unsigned int base, top;
142 int nodes = 0;
143 int registers = 0;
144 int this_registers, average;
145
146 map->lock(map);
147
148 for (node = rb_first(&rbtree_ctx->root); node != NULL;
149 node = rb_next(node)) {
150 n = container_of(node, struct regcache_rbtree_node, node);
151
152 regcache_rbtree_get_base_top_reg(map, n, &base, &top);
153 this_registers = ((top - base) / map->reg_stride) + 1;
154 seq_printf(s, "%x-%x (%d)\n", base, top, this_registers);
155
156 nodes++;
157 registers += this_registers;
158 }
159
160 if (nodes)
161 average = registers / nodes;
162 else
163 average = 0;
164
165 seq_printf(s, "%d nodes, %d registers, average %d registers\n",
166 nodes, registers, average);
167
168 map->unlock(map);
169
170 return 0;
171}
172
173static int rbtree_open(struct inode *inode, struct file *file)
174{
175 return single_open(file, rbtree_show, inode->i_private);
176}
177
178static const struct file_operations rbtree_fops = {
179 .open = rbtree_open,
180 .read = seq_read,
181 .llseek = seq_lseek,
182 .release = single_release,
183};
184
185static void rbtree_debugfs_init(struct regmap *map)
186{
187 debugfs_create_file("rbtree", 0400, map->debugfs, map, &rbtree_fops);
188}
189#else
190static void rbtree_debugfs_init(struct regmap *map)
191{
192}
193#endif
194
195static int regcache_rbtree_init(struct regmap *map)
196{
197 struct regcache_rbtree_ctx *rbtree_ctx;
198 int i;
199 int ret;
200
201 map->cache = kmalloc(sizeof *rbtree_ctx, GFP_KERNEL);
202 if (!map->cache)
203 return -ENOMEM;
204
205 rbtree_ctx = map->cache;
206 rbtree_ctx->root = RB_ROOT;
207 rbtree_ctx->cached_rbnode = NULL;
208
209 for (i = 0; i < map->num_reg_defaults; i++) {
210 ret = regcache_rbtree_write(map,
211 map->reg_defaults[i].reg,
212 map->reg_defaults[i].def);
213 if (ret)
214 goto err;
215 }
216
217 rbtree_debugfs_init(map);
218
219 return 0;
220
221err:
222 regcache_rbtree_exit(map);
223 return ret;
224}
225
226static int regcache_rbtree_exit(struct regmap *map)
227{
228 struct rb_node *next;
229 struct regcache_rbtree_ctx *rbtree_ctx;
230 struct regcache_rbtree_node *rbtree_node;
231
232 /* if we've already been called then just return */
233 rbtree_ctx = map->cache;
234 if (!rbtree_ctx)
235 return 0;
236
237 /* free up the rbtree */
238 next = rb_first(&rbtree_ctx->root);
239 while (next) {
240 rbtree_node = rb_entry(next, struct regcache_rbtree_node, node);
241 next = rb_next(&rbtree_node->node);
242 rb_erase(&rbtree_node->node, &rbtree_ctx->root);
243 kfree(rbtree_node->block);
244 kfree(rbtree_node);
245 }
246
247 /* release the resources */
248 kfree(map->cache);
249 map->cache = NULL;
250
251 return 0;
252}
253
254static int regcache_rbtree_read(struct regmap *map,
255 unsigned int reg, unsigned int *value)
256{
257 struct regcache_rbtree_node *rbnode;
258 unsigned int reg_tmp;
259
260 rbnode = regcache_rbtree_lookup(map, reg);
261 if (rbnode) {
262 reg_tmp = (reg - rbnode->base_reg) / map->reg_stride;
263 *value = regcache_rbtree_get_register(rbnode, reg_tmp,
264 map->cache_word_size);
265 } else {
266 return -ENOENT;
267 }
268
269 return 0;
270}
271
272
273static int regcache_rbtree_insert_to_block(struct regcache_rbtree_node *rbnode,
274 unsigned int pos, unsigned int reg,
275 unsigned int value, unsigned int word_size)
276{
277 u8 *blk;
278
279 blk = krealloc(rbnode->block,
280 (rbnode->blklen + 1) * word_size, GFP_KERNEL);
281 if (!blk)
282 return -ENOMEM;
283
284 /* insert the register value in the correct place in the rbnode block */
285 memmove(blk + (pos + 1) * word_size,
286 blk + pos * word_size,
287 (rbnode->blklen - pos) * word_size);
288
289 /* update the rbnode block, its size and the base register */
290 rbnode->block = blk;
291 rbnode->blklen++;
292 if (!pos)
293 rbnode->base_reg = reg;
294
295 regcache_rbtree_set_register(rbnode, pos, value, word_size);
296 return 0;
297}
298
299static int regcache_rbtree_write(struct regmap *map, unsigned int reg,
300 unsigned int value)
301{
302 struct regcache_rbtree_ctx *rbtree_ctx;
303 struct regcache_rbtree_node *rbnode, *rbnode_tmp;
304 struct rb_node *node;
305 unsigned int val;
306 unsigned int reg_tmp;
307 unsigned int pos;
308 int i;
309 int ret;
310
311 rbtree_ctx = map->cache;
312 /* if we can't locate it in the cached rbnode we'll have
313 * to traverse the rbtree looking for it.
314 */
315 rbnode = regcache_rbtree_lookup(map, reg);
316 if (rbnode) {
317 reg_tmp = (reg - rbnode->base_reg) / map->reg_stride;
318 val = regcache_rbtree_get_register(rbnode, reg_tmp,
319 map->cache_word_size);
320 if (val == value)
321 return 0;
322 regcache_rbtree_set_register(rbnode, reg_tmp, value,
323 map->cache_word_size);
324 } else {
325 /* look for an adjacent register to the one we are about to add */
326 for (node = rb_first(&rbtree_ctx->root); node;
327 node = rb_next(node)) {
328 rbnode_tmp = rb_entry(node, struct regcache_rbtree_node,
329 node);
330 for (i = 0; i < rbnode_tmp->blklen; i++) {
331 reg_tmp = rbnode_tmp->base_reg +
332 (i * map->reg_stride);
333 if (abs(reg_tmp - reg) != map->reg_stride)
334 continue;
335 /* decide where in the block to place our register */
336 if (reg_tmp + map->reg_stride == reg)
337 pos = i + 1;
338 else
339 pos = i;
340 ret = regcache_rbtree_insert_to_block(rbnode_tmp, pos,
341 reg, value,
342 map->cache_word_size);
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(rbnode, 0, value, map->cache_word_size);
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(rbnode, i,
408 map->cache_word_size);
409
410 /* Is this the hardware default? If so skip. */
411 ret = regcache_lookup_reg(map, regtmp);
412 if (ret >= 0 && val == map->reg_defaults[ret].def)
413 continue;
414
415 map->cache_bypass = 1;
416 ret = _regmap_write(map, regtmp, val);
417 map->cache_bypass = 0;
418 if (ret)
419 return ret;
420 dev_dbg(map->dev, "Synced register %#x, value %#x\n",
421 regtmp, val);
422 }
423 }
424
425 return 0;
426}
427
428struct regcache_ops regcache_rbtree_ops = {
429 .type = REGCACHE_RBTREE,
430 .name = "rbtree",
431 .init = regcache_rbtree_init,
432 .exit = regcache_rbtree_exit,
433 .read = regcache_rbtree_read,
434 .write = regcache_rbtree_write,
435 .sync = regcache_rbtree_sync
436};