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