[linux-block.git] / drivers / base / regmap / regcache-rbtree.c

/*
 * Register cache access API - rbtree caching support
 *
 * Copyright 2011 Wolfson Microelectronics plc
 *
 * Author: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/slab.h>
#include <linux/device.h>
#include <linux/debugfs.h>
#include <linux/rbtree.h>
#include <linux/seq_file.h>

#include "internal.h"

static int regcache_rbtree_write(struct regmap *map, unsigned int reg,
				 unsigned int value);
static int regcache_rbtree_exit(struct regmap *map);

struct regcache_rbtree_node {
	/* the actual rbtree node holding this block */
	struct rb_node node;
	/* base register handled by this block */
	unsigned int base_reg;
	/* block of adjacent registers */
	void *block;
	/* number of registers available in the block */
	unsigned int blklen;
} __attribute__ ((packed));

struct regcache_rbtree_ctx {
	struct rb_root root;
	struct regcache_rbtree_node *cached_rbnode;
};

static inline void regcache_rbtree_get_base_top_reg(
	struct regcache_rbtree_node *rbnode,
	unsigned int *base, unsigned int *top)
{
	*base = rbnode->base_reg;
	*top = rbnode->base_reg + rbnode->blklen - 1;
}

static unsigned int regcache_rbtree_get_register(
	struct regcache_rbtree_node *rbnode, unsigned int idx,
	unsigned int word_size)
{
	return regcache_get_val(rbnode->block, idx, word_size);
}

static void regcache_rbtree_set_register(struct regcache_rbtree_node *rbnode,
					 unsigned int idx, unsigned int val,
					 unsigned int word_size)
{
	regcache_set_val(rbnode->block, idx, val, word_size);
}

static struct regcache_rbtree_node *regcache_rbtree_lookup(struct regmap *map,
	unsigned int reg)
{
	struct regcache_rbtree_ctx *rbtree_ctx = map->cache;
	struct rb_node *node;
	struct regcache_rbtree_node *rbnode;
	unsigned int base_reg, top_reg;

	rbnode = rbtree_ctx->cached_rbnode;
	if (rbnode) {
		regcache_rbtree_get_base_top_reg(rbnode, &base_reg, &top_reg);
		if (reg >= base_reg && reg <= top_reg)
			return rbnode;
	}

	node = rbtree_ctx->root.rb_node;
	while (node) {
		rbnode = container_of(node, struct regcache_rbtree_node, node);
		regcache_rbtree_get_base_top_reg(rbnode, &base_reg, &top_reg);
		if (reg >= base_reg && reg <= top_reg) {
			rbtree_ctx->cached_rbnode = rbnode;
			return rbnode;
		} else if (reg > top_reg) {
			node = node->rb_right;
		} else if (reg < base_reg) {
			node = node->rb_left;
		}
	}

	return NULL;
}

static int regcache_rbtree_insert(struct rb_root *root,
				  struct regcache_rbtree_node *rbnode)
{
	struct rb_node **new, *parent;
	struct regcache_rbtree_node *rbnode_tmp;
	unsigned int base_reg_tmp, top_reg_tmp;
	unsigned int base_reg;

	parent = NULL;
	new = &root->rb_node;
	while (*new) {
		rbnode_tmp = container_of(*new, struct regcache_rbtree_node,
					  node);
		/* base and top registers of the current rbnode */
		regcache_rbtree_get_base_top_reg(rbnode_tmp, &base_reg_tmp,
						 &top_reg_tmp);
		/* base register of the rbnode to be added */
		base_reg = rbnode->base_reg;
		parent = *new;
		/* if this register has already been inserted, just return */
		if (base_reg >= base_reg_tmp &&
		    base_reg <= top_reg_tmp)
			return 0;
		else if (base_reg > top_reg_tmp)
			new = &((*new)->rb_right);
		else if (base_reg < base_reg_tmp)
			new = &((*new)->rb_left);
	}

	/* insert the node into the rbtree */
	rb_link_node(&rbnode->node, parent, new);
	rb_insert_color(&rbnode->node, root);

	return 1;
}

#ifdef CONFIG_DEBUG_FS
static int rbtree_show(struct seq_file *s, void *ignored)
{
	struct regmap *map = s->private;
	struct regcache_rbtree_ctx *rbtree_ctx = map->cache;
	struct regcache_rbtree_node *n;
	struct rb_node *node;
	unsigned int base, top;
	int nodes = 0;
	int registers = 0;
	int average;

	map->lock(map);

	for (node = rb_first(&rbtree_ctx->root); node != NULL;
	     node = rb_next(node)) {
		n = container_of(node, struct regcache_rbtree_node, node);

		regcache_rbtree_get_base_top_reg(n, &base, &top);
		seq_printf(s, "%x-%x (%d)\n", base, top, top - base + 1);

		nodes++;
		registers += top - base + 1;
	}

	if (nodes)
		average = registers / nodes;
	else
		average = 0;

	seq_printf(s, "%d nodes, %d registers, average %d registers\n",
		   nodes, registers, average);

	map->unlock(map);

	return 0;
}

static int rbtree_open(struct inode *inode, struct file *file)
{
	return single_open(file, rbtree_show, inode->i_private);
}

static const struct file_operations rbtree_fops = {
	.open		= rbtree_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
};

static void rbtree_debugfs_init(struct regmap *map)
{
	debugfs_create_file("rbtree", 0400, map->debugfs, map, &rbtree_fops);
}
#else
static void rbtree_debugfs_init(struct regmap *map)
{
}
#endif

static int regcache_rbtree_init(struct regmap *map)
{
	struct regcache_rbtree_ctx *rbtree_ctx;
	int i;
	int ret;

	map->cache = kmalloc(sizeof *rbtree_ctx, GFP_KERNEL);
	if (!map->cache)
		return -ENOMEM;

	rbtree_ctx = map->cache;
	rbtree_ctx->root = RB_ROOT;
	rbtree_ctx->cached_rbnode = NULL;

	for (i = 0; i < map->num_reg_defaults; i++) {
		ret = regcache_rbtree_write(map,
					    map->reg_defaults[i].reg,
					    map->reg_defaults[i].def);
		if (ret)
			goto err;
	}

	rbtree_debugfs_init(map);

	return 0;

err:
	regcache_rbtree_exit(map);
	return ret;
}

static int regcache_rbtree_exit(struct regmap *map)
{
	struct rb_node *next;
	struct regcache_rbtree_ctx *rbtree_ctx;
	struct regcache_rbtree_node *rbtree_node;

	/* if we've already been called then just return */
	rbtree_ctx = map->cache;
	if (!rbtree_ctx)
		return 0;

	/* free up the rbtree */
	next = rb_first(&rbtree_ctx->root);
	while (next) {
		rbtree_node = rb_entry(next, struct regcache_rbtree_node, node);
		next = rb_next(&rbtree_node->node);
		rb_erase(&rbtree_node->node, &rbtree_ctx->root);
		kfree(rbtree_node->block);
		kfree(rbtree_node);
	}

	/* release the resources */
	kfree(map->cache);
	map->cache = NULL;

	return 0;
}

static int regcache_rbtree_read(struct regmap *map,
				unsigned int reg, unsigned int *value)
{
	struct regcache_rbtree_node *rbnode;
	unsigned int reg_tmp;

	rbnode = regcache_rbtree_lookup(map, reg);
	if (rbnode) {
		reg_tmp = reg - rbnode->base_reg;
		*value = regcache_rbtree_get_register(rbnode, reg_tmp,
						      map->cache_word_size);
	} else {
		return -ENOENT;
	}

	return 0;
}


static int regcache_rbtree_insert_to_block(struct regcache_rbtree_node *rbnode,
					   unsigned int pos, unsigned int reg,
					   unsigned int value, unsigned int word_size)
{
	u8 *blk;

	blk = krealloc(rbnode->block,
		       (rbnode->blklen + 1) * word_size, GFP_KERNEL);
	if (!blk)
		return -ENOMEM;

	/* insert the register value in the correct place in the rbnode block */
	memmove(blk + (pos + 1) * word_size,
		blk + pos * word_size,
		(rbnode->blklen - pos) * word_size);

	/* update the rbnode block, its size and the base register */
	rbnode->block = blk;
	rbnode->blklen++;
	if (!pos)
		rbnode->base_reg = reg;

	regcache_rbtree_set_register(rbnode, pos, value, word_size);
	return 0;
}

static int regcache_rbtree_write(struct regmap *map, unsigned int reg,
				 unsigned int value)
{
	struct regcache_rbtree_ctx *rbtree_ctx;
	struct regcache_rbtree_node *rbnode, *rbnode_tmp;
	struct rb_node *node;
	unsigned int val;
	unsigned int reg_tmp;
	unsigned int pos;
	int i;
	int ret;

	rbtree_ctx = map->cache;
	/* if we can't locate it in the cached rbnode we'll have
	 * to traverse the rbtree looking for it.
	 */
	rbnode = regcache_rbtree_lookup(map, reg);
	if (rbnode) {
		reg_tmp = reg - rbnode->base_reg;
		val = regcache_rbtree_get_register(rbnode, reg_tmp,
						   map->cache_word_size);
		if (val == value)
			return 0;
		regcache_rbtree_set_register(rbnode, reg_tmp, value,
					     map->cache_word_size);
	} else {
		/* look for an adjacent register to the one we are about to add */
		for (node = rb_first(&rbtree_ctx->root); node;
		     node = rb_next(node)) {
			rbnode_tmp = rb_entry(node, struct regcache_rbtree_node, node);
			for (i = 0; i < rbnode_tmp->blklen; i++) {
				reg_tmp = rbnode_tmp->base_reg + i;
				if (abs(reg_tmp - reg) != 1)
					continue;
				/* decide where in the block to place our register */
				if (reg_tmp + 1 == reg)
					pos = i + 1;
				else
					pos = i;
				ret = regcache_rbtree_insert_to_block(rbnode_tmp, pos,
								      reg, value,
								      map->cache_word_size);
				if (ret)
					return ret;
				rbtree_ctx->cached_rbnode = rbnode_tmp;
				return 0;
			}
		}
		/* we did not manage to find a place to insert it in an existing
		 * block so create a new rbnode with a single register in its block.
		 * This block will get populated further if any other adjacent
		 * registers get modified in the future.
		 */
		rbnode = kzalloc(sizeof *rbnode, GFP_KERNEL);
		if (!rbnode)
			return -ENOMEM;
		rbnode->blklen = 1;
		rbnode->base_reg = reg;
		rbnode->block = kmalloc(rbnode->blklen * map->cache_word_size,
					GFP_KERNEL);
		if (!rbnode->block) {
			kfree(rbnode);
			return -ENOMEM;
		}
		regcache_rbtree_set_register(rbnode, 0, value, map->cache_word_size);
		regcache_rbtree_insert(&rbtree_ctx->root, rbnode);
		rbtree_ctx->cached_rbnode = rbnode;
	}

	return 0;
}

static int regcache_rbtree_sync(struct regmap *map, unsigned int min,
				unsigned int max)
{
	struct regcache_rbtree_ctx *rbtree_ctx;
	struct rb_node *node;
	struct regcache_rbtree_node *rbnode;
	unsigned int regtmp;
	unsigned int val;
	int ret;
	int i, base, end;

	rbtree_ctx = map->cache;
	for (node = rb_first(&rbtree_ctx->root); node; node = rb_next(node)) {
		rbnode = rb_entry(node, struct regcache_rbtree_node, node);

		if (rbnode->base_reg < min)
			continue;
		if (rbnode->base_reg > max)
			break;
		if (rbnode->base_reg + rbnode->blklen < min)
			continue;

		if (min > rbnode->base_reg)
			base = min - rbnode->base_reg;
		else
			base = 0;

		if (max < rbnode->base_reg + rbnode->blklen)
			end = rbnode->base_reg + rbnode->blklen - max;
		else
			end = rbnode->blklen;

		for (i = base; i < end; i++) {
			regtmp = rbnode->base_reg + i;
			val = regcache_rbtree_get_register(rbnode, i,
							   map->cache_word_size);

			/* Is this the hardware default?  If so skip. */
			ret = regcache_lookup_reg(map, regtmp);
			if (ret >= 0 && val == map->reg_defaults[ret].def)
				continue;

			map->cache_bypass = 1;
			ret = _regmap_write(map, regtmp, val);
			map->cache_bypass = 0;
			if (ret)
				return ret;
			dev_dbg(map->dev, "Synced register %#x, value %#x\n",
				regtmp, val);
		}
	}

	return 0;
}

struct regcache_ops regcache_rbtree_ops = {
	.type = REGCACHE_RBTREE,
	.name = "rbtree",
	.init = regcache_rbtree_init,
	.exit = regcache_rbtree_exit,
	.read = regcache_rbtree_read,
	.write = regcache_rbtree_write,
	.sync = regcache_rbtree_sync
};
Commit	Line	Data
28644c80 DP	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>
51990e82	14	#include <linux/device.h>
bad2ab4b	15	#include <linux/debugfs.h>
28644c80	16	#include <linux/rbtree.h>
bad2ab4b	17	#include <linux/seq_file.h>
28644c80 DP	18
	19	#include "internal.h"
	20
	21	static int regcache_rbtree_write(struct regmap *map, unsigned int reg,
	22	unsigned int value);
462a185c	23	static int regcache_rbtree_exit(struct regmap *map);
28644c80 DP	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;
28644c80 DP	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 regcache_rbtree_node *rbnode,
	43	unsigned int base, unsigned int top)
	44	{
	45	*base = rbnode->base_reg;
	46	*top = rbnode->base_reg + rbnode->blklen - 1;
	47	}
	48
	49	static unsigned int regcache_rbtree_get_register(
25ed1156 DP	50	struct regcache_rbtree_node *rbnode, unsigned int idx,
25ed1156 DP	51	unsigned int word_size)
28644c80	52	{
c5713004	53	return regcache_get_val(rbnode->block, idx, word_size);
28644c80 DP	54	}
	55
	56	static void regcache_rbtree_set_register(struct regcache_rbtree_node *rbnode,
25ed1156 DP	57	unsigned int idx, unsigned int val,
25ed1156 DP	58	unsigned int word_size)
28644c80	59	{
c5713004	60	regcache_set_val(rbnode->block, idx, val, word_size);
28644c80 DP	61	}
28644c80 DP	62
3405addd LPC	63	static struct regcache_rbtree_node regcache_rbtree_lookup(struct regmap map,
3405addd LPC	64	unsigned int reg)
28644c80	65	{
3405addd	66	struct regcache_rbtree_ctx *rbtree_ctx = map->cache;
28644c80 DP	67	struct rb_node *node;
	68	struct regcache_rbtree_node *rbnode;
	69	unsigned int base_reg, top_reg;
	70
3405addd LPC	71	rbnode = rbtree_ctx->cached_rbnode;
	72	if (rbnode) {
	73	regcache_rbtree_get_base_top_reg(rbnode, &base_reg, &top_reg);
	74	if (reg >= base_reg && reg <= top_reg)
	75	return rbnode;
	76	}
	77
	78	node = rbtree_ctx->root.rb_node;
28644c80 DP	79	while (node) {
	80	rbnode = container_of(node, struct regcache_rbtree_node, node);
	81	regcache_rbtree_get_base_top_reg(rbnode, &base_reg, &top_reg);
3405addd LPC	82	if (reg >= base_reg && reg <= top_reg) {
3405addd LPC	83	rbtree_ctx->cached_rbnode = rbnode;
28644c80	84	return rbnode;
3405addd	85	} else if (reg > top_reg) {
28644c80	86	node = node->rb_right;
3405addd	87	} else if (reg < base_reg) {
28644c80	88	node = node->rb_left;
3405addd	89	}
28644c80 DP	90	}
	91
	92	return NULL;
	93	}
	94
	95	static int regcache_rbtree_insert(struct rb_root *root,
	96	struct regcache_rbtree_node *rbnode)
	97	{
	98	struct rb_node *new, parent;
	99	struct regcache_rbtree_node *rbnode_tmp;
	100	unsigned int base_reg_tmp, top_reg_tmp;
	101	unsigned int base_reg;
	102
	103	parent = NULL;
	104	new = &root->rb_node;
	105	while (*new) {
	106	rbnode_tmp = container_of(*new, struct regcache_rbtree_node,
	107	node);
	108	/* base and top registers of the current rbnode */
	109	regcache_rbtree_get_base_top_reg(rbnode_tmp, &base_reg_tmp,
	110	&top_reg_tmp);
	111	/* base register of the rbnode to be added */
	112	base_reg = rbnode->base_reg;
	113	parent = *new;
	114	/* if this register has already been inserted, just return */
	115	if (base_reg >= base_reg_tmp &&
	116	base_reg <= top_reg_tmp)
	117	return 0;
	118	else if (base_reg > top_reg_tmp)
	119	new = &((*new)->rb_right);
	120	else if (base_reg < base_reg_tmp)
	121	new = &((*new)->rb_left);
	122	}
	123
	124	/* insert the node into the rbtree */
	125	rb_link_node(&rbnode->node, parent, new);
	126	rb_insert_color(&rbnode->node, root);
	127
	128	return 1;
	129	}
	130
bad2ab4b MB	131	#ifdef CONFIG_DEBUG_FS
	132	static int rbtree_show(struct seq_file s, void ignored)
	133	{
	134	struct regmap *map = s->private;
	135	struct regcache_rbtree_ctx *rbtree_ctx = map->cache;
	136	struct regcache_rbtree_node *n;
	137	struct rb_node *node;
	138	unsigned int base, top;
	139	int nodes = 0;
	140	int registers = 0;
c04c1b9e	141	int average;
bad2ab4b	142
bacdbe07	143	map->lock(map);
bad2ab4b MB	144
	145	for (node = rb_first(&rbtree_ctx->root); node != NULL;
	146	node = rb_next(node)) {
	147	n = container_of(node, struct regcache_rbtree_node, node);
	148
	149	regcache_rbtree_get_base_top_reg(n, &base, &top);
	150	seq_printf(s, "%x-%x (%d)\n", base, top, top - base + 1);
	151
	152	nodes++;
	153	registers += top - base + 1;
	154	}
	155
c04c1b9e SW	156	if (nodes)
	157	average = registers / nodes;
	158	else
	159	average = 0;
	160
bad2ab4b	161	seq_printf(s, "%d nodes, %d registers, average %d registers\n",
c04c1b9e	162	nodes, registers, average);
bad2ab4b	163
bacdbe07	164	map->unlock(map);
bad2ab4b MB	165
	166	return 0;
	167	}
	168
	169	static int rbtree_open(struct inode inode, struct file file)
	170	{
	171	return single_open(file, rbtree_show, inode->i_private);
	172	}
	173
	174	static const struct file_operations rbtree_fops = {
	175	.open = rbtree_open,
	176	.read = seq_read,
	177	.llseek = seq_lseek,
	178	.release = single_release,
	179	};
cce585ce MB	180
	181	static void rbtree_debugfs_init(struct regmap *map)
	182	{
	183	debugfs_create_file("rbtree", 0400, map->debugfs, map, &rbtree_fops);
	184	}
	185	#else
	186	static void rbtree_debugfs_init(struct regmap *map)
	187	{
	188	}
bad2ab4b MB	189	#endif
bad2ab4b MB	190
28644c80 DP	191	static int regcache_rbtree_init(struct regmap *map)
	192	{
	193	struct regcache_rbtree_ctx *rbtree_ctx;
	194	int i;
	195	int ret;
	196
	197	map->cache = kmalloc(sizeof *rbtree_ctx, GFP_KERNEL);
	198	if (!map->cache)
	199	return -ENOMEM;
	200
	201	rbtree_ctx = map->cache;
	202	rbtree_ctx->root = RB_ROOT;
	203	rbtree_ctx->cached_rbnode = NULL;
	204
	205	for (i = 0; i < map->num_reg_defaults; i++) {
	206	ret = regcache_rbtree_write(map,
	207	map->reg_defaults[i].reg,
	208	map->reg_defaults[i].def);
	209	if (ret)
	210	goto err;
	211	}
	212
cce585ce	213	rbtree_debugfs_init(map);
bad2ab4b	214
28644c80 DP	215	return 0;
	216
	217	err:
462a185c	218	regcache_rbtree_exit(map);
28644c80 DP	219	return ret;
	220	}
	221
	222	static int regcache_rbtree_exit(struct regmap *map)
	223	{
	224	struct rb_node *next;
	225	struct regcache_rbtree_ctx *rbtree_ctx;
	226	struct regcache_rbtree_node *rbtree_node;
	227
	228	/* if we've already been called then just return */
	229	rbtree_ctx = map->cache;
	230	if (!rbtree_ctx)
	231	return 0;
	232
	233	/* free up the rbtree */
	234	next = rb_first(&rbtree_ctx->root);
	235	while (next) {
	236	rbtree_node = rb_entry(next, struct regcache_rbtree_node, node);
	237	next = rb_next(&rbtree_node->node);
	238	rb_erase(&rbtree_node->node, &rbtree_ctx->root);
	239	kfree(rbtree_node->block);
	240	kfree(rbtree_node);
	241	}
	242
	243	/* release the resources */
	244	kfree(map->cache);
	245	map->cache = NULL;
	246
	247	return 0;
	248	}
	249
	250	static int regcache_rbtree_read(struct regmap *map,
	251	unsigned int reg, unsigned int *value)
	252	{
28644c80	253	struct regcache_rbtree_node *rbnode;
28644c80 DP	254	unsigned int reg_tmp;
28644c80 DP	255
3405addd	256	rbnode = regcache_rbtree_lookup(map, reg);
28644c80 DP	257	if (rbnode) {
28644c80 DP	258	reg_tmp = reg - rbnode->base_reg;
25ed1156 DP	259	*value = regcache_rbtree_get_register(rbnode, reg_tmp,
25ed1156 DP	260	map->cache_word_size);
28644c80	261	} else {
6e6ace00	262	return -ENOENT;
28644c80 DP	263	}
	264
	265	return 0;
	266	}
	267
	268
	269	static int regcache_rbtree_insert_to_block(struct regcache_rbtree_node *rbnode,
	270	unsigned int pos, unsigned int reg,
25ed1156	271	unsigned int value, unsigned int word_size)
28644c80 DP	272	{
	273	u8 *blk;
	274
	275	blk = krealloc(rbnode->block,
25ed1156	276	(rbnode->blklen + 1) * word_size, GFP_KERNEL);
28644c80 DP	277	if (!blk)
	278	return -ENOMEM;
	279
	280	/* insert the register value in the correct place in the rbnode block */
25ed1156 DP	281	memmove(blk + (pos + 1) * word_size,
	282	blk + pos * word_size,
	283	(rbnode->blklen - pos) * word_size);
28644c80 DP	284
	285	/* update the rbnode block, its size and the base register */
	286	rbnode->block = blk;
	287	rbnode->blklen++;
	288	if (!pos)
	289	rbnode->base_reg = reg;
	290
25ed1156	291	regcache_rbtree_set_register(rbnode, pos, value, word_size);
28644c80 DP	292	return 0;
	293	}
	294
	295	static int regcache_rbtree_write(struct regmap *map, unsigned int reg,
	296	unsigned int value)
	297	{
	298	struct regcache_rbtree_ctx *rbtree_ctx;
	299	struct regcache_rbtree_node rbnode, rbnode_tmp;
	300	struct rb_node *node;
	301	unsigned int val;
	302	unsigned int reg_tmp;
28644c80 DP	303	unsigned int pos;
	304	int i;
	305	int ret;
	306
	307	rbtree_ctx = map->cache;
28644c80 DP	308	/* if we can't locate it in the cached rbnode we'll have
	309	* to traverse the rbtree looking for it.
	310	*/
3405addd	311	rbnode = regcache_rbtree_lookup(map, reg);
28644c80 DP	312	if (rbnode) {
28644c80 DP	313	reg_tmp = reg - rbnode->base_reg;
25ed1156 DP	314	val = regcache_rbtree_get_register(rbnode, reg_tmp,
25ed1156 DP	315	map->cache_word_size);
28644c80 DP	316	if (val == value)
28644c80 DP	317	return 0;
25ed1156 DP	318	regcache_rbtree_set_register(rbnode, reg_tmp, value,
25ed1156 DP	319	map->cache_word_size);
28644c80	320	} else {
28644c80 DP	321	/* look for an adjacent register to the one we are about to add */
	322	for (node = rb_first(&rbtree_ctx->root); node;
	323	node = rb_next(node)) {
	324	rbnode_tmp = rb_entry(node, struct regcache_rbtree_node, node);
	325	for (i = 0; i < rbnode_tmp->blklen; i++) {
	326	reg_tmp = rbnode_tmp->base_reg + i;
	327	if (abs(reg_tmp - reg) != 1)
	328	continue;
	329	/* decide where in the block to place our register */
	330	if (reg_tmp + 1 == reg)
	331	pos = i + 1;
	332	else
	333	pos = i;
	334	ret = regcache_rbtree_insert_to_block(rbnode_tmp, pos,
25ed1156 DP	335	reg, value,
25ed1156 DP	336	map->cache_word_size);
28644c80 DP	337	if (ret)
	338	return ret;
	339	rbtree_ctx->cached_rbnode = rbnode_tmp;
	340	return 0;
	341	}
	342	}
	343	/* we did not manage to find a place to insert it in an existing
	344	* block so create a new rbnode with a single register in its block.
	345	* This block will get populated further if any other adjacent
	346	* registers get modified in the future.
	347	*/
	348	rbnode = kzalloc(sizeof *rbnode, GFP_KERNEL);
	349	if (!rbnode)
	350	return -ENOMEM;
	351	rbnode->blklen = 1;
	352	rbnode->base_reg = reg;
25ed1156	353	rbnode->block = kmalloc(rbnode->blklen * map->cache_word_size,
28644c80 DP	354	GFP_KERNEL);
	355	if (!rbnode->block) {
	356	kfree(rbnode);
	357	return -ENOMEM;
	358	}
25ed1156	359	regcache_rbtree_set_register(rbnode, 0, value, map->cache_word_size);
28644c80 DP	360	regcache_rbtree_insert(&rbtree_ctx->root, rbnode);
	361	rbtree_ctx->cached_rbnode = rbnode;
	362	}
	363
	364	return 0;
	365	}
	366
ac8d91c8 MB	367	static int regcache_rbtree_sync(struct regmap *map, unsigned int min,
ac8d91c8 MB	368	unsigned int max)
28644c80 DP	369	{
	370	struct regcache_rbtree_ctx *rbtree_ctx;
	371	struct rb_node *node;
	372	struct regcache_rbtree_node *rbnode;
	373	unsigned int regtmp;
b03622a8	374	unsigned int val;
28644c80	375	int ret;
ac8d91c8	376	int i, base, end;
28644c80 DP	377
	378	rbtree_ctx = map->cache;
	379	for (node = rb_first(&rbtree_ctx->root); node; node = rb_next(node)) {
	380	rbnode = rb_entry(node, struct regcache_rbtree_node, node);
ac8d91c8 MB	381
	382	if (rbnode->base_reg < min)
	383	continue;
	384	if (rbnode->base_reg > max)
	385	break;
	386	if (rbnode->base_reg + rbnode->blklen < min)
	387	continue;
	388
f9353e70	389	if (min > rbnode->base_reg)
ac8d91c8 MB	390	base = min - rbnode->base_reg;
	391	else
	392	base = 0;
	393
	394	if (max < rbnode->base_reg + rbnode->blklen)
	395	end = rbnode->base_reg + rbnode->blklen - max;
	396	else
	397	end = rbnode->blklen;
	398
	399	for (i = base; i < end; i++) {
28644c80	400	regtmp = rbnode->base_reg + i;
25ed1156 DP	401	val = regcache_rbtree_get_register(rbnode, i,
25ed1156 DP	402	map->cache_word_size);
b03622a8 MB	403
b03622a8 MB	404	/* Is this the hardware default? If so skip. */
4b4e9e43	405	ret = regcache_lookup_reg(map, regtmp);
994f5db6	406	if (ret >= 0 && val == map->reg_defaults[ret].def)
28644c80	407	continue;
b03622a8	408
28644c80	409	map->cache_bypass = 1;
13753a90	410	ret = _regmap_write(map, regtmp, val);
28644c80 DP	411	map->cache_bypass = 0;
	412	if (ret)
	413	return ret;
	414	dev_dbg(map->dev, "Synced register %#x, value %#x\n",
	415	regtmp, val);
	416	}
	417	}
	418
	419	return 0;
	420	}
	421
	422	struct regcache_ops regcache_rbtree_ops = {
	423	.type = REGCACHE_RBTREE,
	424	.name = "rbtree",
	425	.init = regcache_rbtree_init,
	426	.exit = regcache_rbtree_exit,
	427	.read = regcache_rbtree_read,
	428	.write = regcache_rbtree_write,
	429	.sync = regcache_rbtree_sync
	430	};