[go: nahoru, domu]
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	/* 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
38struct regcache_rbtree_ctx {
39	struct rb_root root;
40	struct regcache_rbtree_node *cached_rbnode;
41};
42
43static 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
52static 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
58static 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
66static 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
100static 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
137static 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
181static int rbtree_open(struct inode *inode, struct file *file)
182{
183	return single_open(file, rbtree_show, inode->i_private);
184}
185
186static const struct file_operations rbtree_fops = {
187	.open		= rbtree_open,
188	.read		= seq_read,
189	.llseek		= seq_lseek,
190	.release	= single_release,
191};
192
193static void rbtree_debugfs_init(struct regmap *map)
194{
195	debugfs_create_file("rbtree", 0400, map->debugfs, map, &rbtree_fops);
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	return 0;
222
223err:
224	regcache_rbtree_exit(map);
225	return ret;
226}
227
228static 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
257static 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
277static 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	present = krealloc(rbnode->cache_present,
300		    BITS_TO_LONGS(blklen) * sizeof(*present), GFP_KERNEL);
301	if (!present) {
302		kfree(blk);
303		return -ENOMEM;
304	}
305
306	/* insert the register value in the correct place in the rbnode block */
307	if (pos == 0) {
308		memmove(blk + offset * map->cache_word_size,
309			blk, rbnode->blklen * map->cache_word_size);
310		bitmap_shift_right(present, present, offset, blklen);
311	}
312
313	/* update the rbnode block, its size and the base register */
314	rbnode->block = blk;
315	rbnode->blklen = blklen;
316	rbnode->base_reg = base_reg;
317	rbnode->cache_present = present;
318
319	regcache_rbtree_set_register(map, rbnode, pos, value);
320	return 0;
321}
322
323static struct regcache_rbtree_node *
324regcache_rbtree_node_alloc(struct regmap *map, unsigned int reg)
325{
326	struct regcache_rbtree_node *rbnode;
327	const struct regmap_range *range;
328	int i;
329
330	rbnode = kzalloc(sizeof(*rbnode), GFP_KERNEL);
331	if (!rbnode)
332		return NULL;
333
334	/* If there is a read table then use it to guess at an allocation */
335	if (map->rd_table) {
336		for (i = 0; i < map->rd_table->n_yes_ranges; i++) {
337			if (regmap_reg_in_range(reg,
338						&map->rd_table->yes_ranges[i]))
339				break;
340		}
341
342		if (i != map->rd_table->n_yes_ranges) {
343			range = &map->rd_table->yes_ranges[i];
344			rbnode->blklen = (range->range_max - range->range_min) /
345				map->reg_stride	+ 1;
346			rbnode->base_reg = range->range_min;
347		}
348	}
349
350	if (!rbnode->blklen) {
351		rbnode->blklen = 1;
352		rbnode->base_reg = reg;
353	}
354
355	rbnode->block = kmalloc(rbnode->blklen * map->cache_word_size,
356				GFP_KERNEL);
357	if (!rbnode->block)
358		goto err_free;
359
360	rbnode->cache_present = kzalloc(BITS_TO_LONGS(rbnode->blklen) *
361		sizeof(*rbnode->cache_present), GFP_KERNEL);
362	if (!rbnode->cache_present)
363		goto err_free_block;
364
365	return rbnode;
366
367err_free_block:
368	kfree(rbnode->block);
369err_free:
370	kfree(rbnode);
371	return NULL;
372}
373
374static int regcache_rbtree_write(struct regmap *map, unsigned int reg,
375				 unsigned int value)
376{
377	struct regcache_rbtree_ctx *rbtree_ctx;
378	struct regcache_rbtree_node *rbnode, *rbnode_tmp;
379	struct rb_node *node;
380	unsigned int reg_tmp;
381	int ret;
382
383	rbtree_ctx = map->cache;
384
385	/* if we can't locate it in the cached rbnode we'll have
386	 * to traverse the rbtree looking for it.
387	 */
388	rbnode = regcache_rbtree_lookup(map, reg);
389	if (rbnode) {
390		reg_tmp = (reg - rbnode->base_reg) / map->reg_stride;
391		regcache_rbtree_set_register(map, rbnode, reg_tmp, value);
392	} else {
393		unsigned int base_reg, top_reg;
394		unsigned int new_base_reg, new_top_reg;
395		unsigned int min, max;
396		unsigned int max_dist;
397
398		max_dist = map->reg_stride * sizeof(*rbnode_tmp) /
399			map->cache_word_size;
400		if (reg < max_dist)
401			min = 0;
402		else
403			min = reg - max_dist;
404		max = reg + max_dist;
405
406		/* look for an adjacent register to the one we are about to add */
407		for (node = rb_first(&rbtree_ctx->root); node;
408		     node = rb_next(node)) {
409			rbnode_tmp = rb_entry(node, struct regcache_rbtree_node,
410					      node);
411
412			regcache_rbtree_get_base_top_reg(map, rbnode_tmp,
413				&base_reg, &top_reg);
414
415			if (base_reg <= max && top_reg >= min) {
416				new_base_reg = min(reg, base_reg);
417				new_top_reg = max(reg, top_reg);
418			} else {
419				continue;
420			}
421
422			ret = regcache_rbtree_insert_to_block(map, rbnode_tmp,
423							      new_base_reg,
424							      new_top_reg, reg,
425							      value);
426			if (ret)
427				return ret;
428			rbtree_ctx->cached_rbnode = rbnode_tmp;
429			return 0;
430		}
431
432		/* We did not manage to find a place to insert it in
433		 * an existing block so create a new rbnode.
434		 */
435		rbnode = regcache_rbtree_node_alloc(map, reg);
436		if (!rbnode)
437			return -ENOMEM;
438		regcache_rbtree_set_register(map, rbnode,
439					     reg - rbnode->base_reg, value);
440		regcache_rbtree_insert(map, &rbtree_ctx->root, rbnode);
441		rbtree_ctx->cached_rbnode = rbnode;
442	}
443
444	return 0;
445}
446
447static int regcache_rbtree_sync(struct regmap *map, unsigned int min,
448				unsigned int max)
449{
450	struct regcache_rbtree_ctx *rbtree_ctx;
451	struct rb_node *node;
452	struct regcache_rbtree_node *rbnode;
453	unsigned int base_reg, top_reg;
454	unsigned int start, end;
455	int ret;
456
457	rbtree_ctx = map->cache;
458	for (node = rb_first(&rbtree_ctx->root); node; node = rb_next(node)) {
459		rbnode = rb_entry(node, struct regcache_rbtree_node, node);
460
461		regcache_rbtree_get_base_top_reg(map, rbnode, &base_reg,
462			&top_reg);
463		if (base_reg > max)
464			break;
465		if (top_reg < min)
466			continue;
467
468		if (min > base_reg)
469			start = (min - base_reg) / map->reg_stride;
470		else
471			start = 0;
472
473		if (max < top_reg)
474			end = (max - base_reg) / map->reg_stride + 1;
475		else
476			end = rbnode->blklen;
477
478		ret = regcache_sync_block(map, rbnode->block,
479					  rbnode->cache_present,
480					  rbnode->base_reg, start, end);
481		if (ret != 0)
482			return ret;
483	}
484
485	return regmap_async_complete(map);
486}
487
488static int regcache_rbtree_drop(struct regmap *map, unsigned int min,
489				unsigned int max)
490{
491	struct regcache_rbtree_ctx *rbtree_ctx;
492	struct regcache_rbtree_node *rbnode;
493	struct rb_node *node;
494	unsigned int base_reg, top_reg;
495	unsigned int start, end;
496
497	rbtree_ctx = map->cache;
498	for (node = rb_first(&rbtree_ctx->root); node; node = rb_next(node)) {
499		rbnode = rb_entry(node, struct regcache_rbtree_node, node);
500
501		regcache_rbtree_get_base_top_reg(map, rbnode, &base_reg,
502			&top_reg);
503		if (base_reg > max)
504			break;
505		if (top_reg < min)
506			continue;
507
508		if (min > base_reg)
509			start = (min - base_reg) / map->reg_stride;
510		else
511			start = 0;
512
513		if (max < top_reg)
514			end = (max - base_reg) / map->reg_stride + 1;
515		else
516			end = rbnode->blklen;
517
518		bitmap_clear(rbnode->cache_present, start, end - start);
519	}
520
521	return 0;
522}
523
524struct regcache_ops regcache_rbtree_ops = {
525	.type = REGCACHE_RBTREE,
526	.name = "rbtree",
527	.init = regcache_rbtree_init,
528	.exit = regcache_rbtree_exit,
529#ifdef CONFIG_DEBUG_FS
530	.debugfs_init = rbtree_debugfs_init,
531#endif
532	.read = regcache_rbtree_read,
533	.write = regcache_rbtree_write,
534	.sync = regcache_rbtree_sync,
535	.drop = regcache_rbtree_drop,
536};
537