[deliverable/linux.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/rbtree.h>

#include "internal.h"

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

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;
}

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;
	}

	return 0;

err:
	regcache_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)
{
	struct regcache_rbtree_ctx *rbtree_ctx;
	struct rb_node *node;
	struct regcache_rbtree_node *rbnode;
	unsigned int regtmp;
	unsigned int val, def;
	int ret;
	int i;

	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);
		for (i = 0; i < rbnode->blklen; i++) {
			regtmp = rbnode->base_reg + i;
			val = regcache_rbtree_get_register(rbnode, i,
							   map->cache_word_size);
			ret = regcache_lookup_reg(map, i);
			if (ret < 0)
				def = 0;
			else
				def = map->reg_defaults[ret].def;
			if (val == 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>
	14	#include <linux/rbtree.h>
	15
	16	#include "internal.h"
	17
	18	static int regcache_rbtree_write(struct regmap *map, unsigned int reg,
	19	unsigned int value);
	20
	21	struct regcache_rbtree_node {
	22	/* the actual rbtree node holding this block */
	23	struct rb_node node;
	24	/* base register handled by this block */
	25	unsigned int base_reg;
28644c80 DP	26	/* block of adjacent registers */
	27	void *block;
	28	/* number of registers available in the block */
	29	unsigned int blklen;
	30	} __attribute__ ((packed));
	31
	32	struct regcache_rbtree_ctx {
	33	struct rb_root root;
	34	struct regcache_rbtree_node *cached_rbnode;
	35	};
	36
	37	static inline void regcache_rbtree_get_base_top_reg(
	38	struct regcache_rbtree_node *rbnode,
	39	unsigned int base, unsigned int top)
	40	{
	41	*base = rbnode->base_reg;
	42	*top = rbnode->base_reg + rbnode->blklen - 1;
	43	}
	44
	45	static unsigned int regcache_rbtree_get_register(
25ed1156 DP	46	struct regcache_rbtree_node *rbnode, unsigned int idx,
25ed1156 DP	47	unsigned int word_size)
28644c80	48	{
c5713004	49	return regcache_get_val(rbnode->block, idx, word_size);
28644c80 DP	50	}
	51
	52	static void regcache_rbtree_set_register(struct regcache_rbtree_node *rbnode,
25ed1156 DP	53	unsigned int idx, unsigned int val,
25ed1156 DP	54	unsigned int word_size)
28644c80	55	{
c5713004	56	regcache_set_val(rbnode->block, idx, val, word_size);
28644c80 DP	57	}
28644c80 DP	58
3405addd LPC	59	static struct regcache_rbtree_node regcache_rbtree_lookup(struct regmap map,
3405addd LPC	60	unsigned int reg)
28644c80	61	{
3405addd	62	struct regcache_rbtree_ctx *rbtree_ctx = map->cache;
28644c80 DP	63	struct rb_node *node;
	64	struct regcache_rbtree_node *rbnode;
	65	unsigned int base_reg, top_reg;
	66
3405addd LPC	67	rbnode = rbtree_ctx->cached_rbnode;
	68	if (rbnode) {
	69	regcache_rbtree_get_base_top_reg(rbnode, &base_reg, &top_reg);
	70	if (reg >= base_reg && reg <= top_reg)
	71	return rbnode;
	72	}
	73
	74	node = rbtree_ctx->root.rb_node;
28644c80 DP	75	while (node) {
	76	rbnode = container_of(node, struct regcache_rbtree_node, node);
	77	regcache_rbtree_get_base_top_reg(rbnode, &base_reg, &top_reg);
3405addd LPC	78	if (reg >= base_reg && reg <= top_reg) {
3405addd LPC	79	rbtree_ctx->cached_rbnode = rbnode;
28644c80	80	return rbnode;
3405addd	81	} else if (reg > top_reg) {
28644c80	82	node = node->rb_right;
3405addd	83	} else if (reg < base_reg) {
28644c80	84	node = node->rb_left;
3405addd	85	}
28644c80 DP	86	}
	87
	88	return NULL;
	89	}
	90
	91	static int regcache_rbtree_insert(struct rb_root *root,
	92	struct regcache_rbtree_node *rbnode)
	93	{
	94	struct rb_node *new, parent;
	95	struct regcache_rbtree_node *rbnode_tmp;
	96	unsigned int base_reg_tmp, top_reg_tmp;
	97	unsigned int base_reg;
	98
	99	parent = NULL;
	100	new = &root->rb_node;
	101	while (*new) {
	102	rbnode_tmp = container_of(*new, struct regcache_rbtree_node,
	103	node);
	104	/* base and top registers of the current rbnode */
	105	regcache_rbtree_get_base_top_reg(rbnode_tmp, &base_reg_tmp,
	106	&top_reg_tmp);
	107	/* base register of the rbnode to be added */
	108	base_reg = rbnode->base_reg;
	109	parent = *new;
	110	/* if this register has already been inserted, just return */
	111	if (base_reg >= base_reg_tmp &&
	112	base_reg <= top_reg_tmp)
	113	return 0;
	114	else if (base_reg > top_reg_tmp)
	115	new = &((*new)->rb_right);
	116	else if (base_reg < base_reg_tmp)
	117	new = &((*new)->rb_left);
	118	}
	119
	120	/* insert the node into the rbtree */
	121	rb_link_node(&rbnode->node, parent, new);
	122	rb_insert_color(&rbnode->node, root);
	123
	124	return 1;
	125	}
	126
	127	static int regcache_rbtree_init(struct regmap *map)
	128	{
	129	struct regcache_rbtree_ctx *rbtree_ctx;
	130	int i;
	131	int ret;
	132
	133	map->cache = kmalloc(sizeof *rbtree_ctx, GFP_KERNEL);
	134	if (!map->cache)
	135	return -ENOMEM;
	136
	137	rbtree_ctx = map->cache;
	138	rbtree_ctx->root = RB_ROOT;
	139	rbtree_ctx->cached_rbnode = NULL;
	140
	141	for (i = 0; i < map->num_reg_defaults; i++) {
	142	ret = regcache_rbtree_write(map,
	143	map->reg_defaults[i].reg,
	144	map->reg_defaults[i].def);
	145	if (ret)
	146	goto err;
	147	}
	148
	149	return 0;
150
151	err:
152	regcache_exit(map);
153	return ret;
154	}
155
156	static int regcache_rbtree_exit(struct regmap *map)
157	{
158	struct rb_node *next;
159	struct regcache_rbtree_ctx *rbtree_ctx;
160	struct regcache_rbtree_node *rbtree_node;
161
162	/* if we've already been called then just return */
163	rbtree_ctx = map->cache;
164	if (!rbtree_ctx)
165	return 0;
166
167	/* free up the rbtree */
168	next = rb_first(&rbtree_ctx->root);
169	while (next) {
170	rbtree_node = rb_entry(next, struct regcache_rbtree_node, node);
171	next = rb_next(&rbtree_node->node);
172	rb_erase(&rbtree_node->node, &rbtree_ctx->root);
173	kfree(rbtree_node->block);
174	kfree(rbtree_node);
175	}
176
177	/* release the resources */
178	kfree(map->cache);
179	map->cache = NULL;
180
181	return 0;
182	}
183
184	static int regcache_rbtree_read(struct regmap *map,
185	unsigned int reg, unsigned int *value)
186	{
28644c80	187	struct regcache_rbtree_node *rbnode;
28644c80 DP	188	unsigned int reg_tmp;
28644c80 DP	189
3405addd	190	rbnode = regcache_rbtree_lookup(map, reg);
28644c80 DP	191	if (rbnode) {
28644c80 DP	192	reg_tmp = reg - rbnode->base_reg;
25ed1156 DP	193	*value = regcache_rbtree_get_register(rbnode, reg_tmp,
25ed1156 DP	194	map->cache_word_size);
28644c80	195	} else {
6e6ace00	196	return -ENOENT;
28644c80 DP	197	}
	198
	199	return 0;
	200	}
	201
	202
	203	static int regcache_rbtree_insert_to_block(struct regcache_rbtree_node *rbnode,
	204	unsigned int pos, unsigned int reg,
25ed1156	205	unsigned int value, unsigned int word_size)
28644c80 DP	206	{
	207	u8 *blk;
	208
	209	blk = krealloc(rbnode->block,
25ed1156	210	(rbnode->blklen + 1) * word_size, GFP_KERNEL);
28644c80 DP	211	if (!blk)
	212	return -ENOMEM;
	213
	214	/* insert the register value in the correct place in the rbnode block */
25ed1156 DP	215	memmove(blk + (pos + 1) * word_size,
	216	blk + pos * word_size,
	217	(rbnode->blklen - pos) * word_size);
28644c80 DP	218
	219	/* update the rbnode block, its size and the base register */
	220	rbnode->block = blk;
	221	rbnode->blklen++;
	222	if (!pos)
	223	rbnode->base_reg = reg;
	224
25ed1156	225	regcache_rbtree_set_register(rbnode, pos, value, word_size);
28644c80 DP	226	return 0;
	227	}
	228
	229	static int regcache_rbtree_write(struct regmap *map, unsigned int reg,
	230	unsigned int value)
	231	{
	232	struct regcache_rbtree_ctx *rbtree_ctx;
	233	struct regcache_rbtree_node rbnode, rbnode_tmp;
	234	struct rb_node *node;
	235	unsigned int val;
	236	unsigned int reg_tmp;
28644c80 DP	237	unsigned int pos;
	238	int i;
	239	int ret;
	240
	241	rbtree_ctx = map->cache;
28644c80 DP	242	/* if we can't locate it in the cached rbnode we'll have
	243	* to traverse the rbtree looking for it.
	244	*/
3405addd	245	rbnode = regcache_rbtree_lookup(map, reg);
28644c80 DP	246	if (rbnode) {
28644c80 DP	247	reg_tmp = reg - rbnode->base_reg;
25ed1156 DP	248	val = regcache_rbtree_get_register(rbnode, reg_tmp,
25ed1156 DP	249	map->cache_word_size);
28644c80 DP	250	if (val == value)
28644c80 DP	251	return 0;
25ed1156 DP	252	regcache_rbtree_set_register(rbnode, reg_tmp, value,
25ed1156 DP	253	map->cache_word_size);
28644c80	254	} else {
28644c80 DP	255	/* look for an adjacent register to the one we are about to add */
	256	for (node = rb_first(&rbtree_ctx->root); node;
	257	node = rb_next(node)) {
	258	rbnode_tmp = rb_entry(node, struct regcache_rbtree_node, node);
	259	for (i = 0; i < rbnode_tmp->blklen; i++) {
	260	reg_tmp = rbnode_tmp->base_reg + i;
	261	if (abs(reg_tmp - reg) != 1)
	262	continue;
	263	/* decide where in the block to place our register */
	264	if (reg_tmp + 1 == reg)
	265	pos = i + 1;
	266	else
	267	pos = i;
	268	ret = regcache_rbtree_insert_to_block(rbnode_tmp, pos,
25ed1156 DP	269	reg, value,
25ed1156 DP	270	map->cache_word_size);
28644c80 DP	271	if (ret)
	272	return ret;
	273	rbtree_ctx->cached_rbnode = rbnode_tmp;
	274	return 0;
	275	}
	276	}
	277	/* we did not manage to find a place to insert it in an existing
	278	* block so create a new rbnode with a single register in its block.
	279	* This block will get populated further if any other adjacent
	280	* registers get modified in the future.
	281	*/
	282	rbnode = kzalloc(sizeof *rbnode, GFP_KERNEL);
	283	if (!rbnode)
	284	return -ENOMEM;
	285	rbnode->blklen = 1;
	286	rbnode->base_reg = reg;
25ed1156	287	rbnode->block = kmalloc(rbnode->blklen * map->cache_word_size,
28644c80 DP	288	GFP_KERNEL);
	289	if (!rbnode->block) {
	290	kfree(rbnode);
	291	return -ENOMEM;
	292	}
25ed1156	293	regcache_rbtree_set_register(rbnode, 0, value, map->cache_word_size);
28644c80 DP	294	regcache_rbtree_insert(&rbtree_ctx->root, rbnode);
	295	rbtree_ctx->cached_rbnode = rbnode;
	296	}
	297
	298	return 0;
	299	}
	300
	301	static int regcache_rbtree_sync(struct regmap *map)
	302	{
	303	struct regcache_rbtree_ctx *rbtree_ctx;
	304	struct rb_node *node;
	305	struct regcache_rbtree_node *rbnode;
	306	unsigned int regtmp;
	307	unsigned int val, def;
	308	int ret;
	309	int i;
	310
	311	rbtree_ctx = map->cache;
	312	for (node = rb_first(&rbtree_ctx->root); node; node = rb_next(node)) {
	313	rbnode = rb_entry(node, struct regcache_rbtree_node, node);
	314	for (i = 0; i < rbnode->blklen; i++) {
	315	regtmp = rbnode->base_reg + i;
25ed1156 DP	316	val = regcache_rbtree_get_register(rbnode, i,
25ed1156 DP	317	map->cache_word_size);
28644c80 DP	318	ret = regcache_lookup_reg(map, i);
	319	if (ret < 0)
	320	def = 0;
	321	else
	322	def = map->reg_defaults[ret].def;
	323	if (val == def)
	324	continue;
	325	map->cache_bypass = 1;
13753a90	326	ret = _regmap_write(map, regtmp, val);
28644c80 DP	327	map->cache_bypass = 0;
	328	if (ret)
	329	return ret;
	330	dev_dbg(map->dev, "Synced register %#x, value %#x\n",
	331	regtmp, val);
	332	}
	333	}
	334
	335	return 0;
	336	}
	337
	338	struct regcache_ops regcache_rbtree_ops = {
	339	.type = REGCACHE_RBTREE,
	340	.name = "rbtree",
	341	.init = regcache_rbtree_init,
	342	.exit = regcache_rbtree_exit,
	343	.read = regcache_rbtree_read,
	344	.write = regcache_rbtree_write,
	345	.sync = regcache_rbtree_sync
	346	};