5 files changed, 403 insertions, 1 deletions

diff --git a/drivers/base/regmap/Makefile b/drivers/base/regmap/Makefile
index 418d151eb30b..20cd65035fc7 100644
--- a/drivers/base/regmap/Makefile
+++ b/drivers/base/regmap/Makefile
@@ -1,4 +1,4 @@
-obj-$(CONFIG_REGMAP) += regmap.o regcache.o regcache-indexed.o
+obj-$(CONFIG_REGMAP) += regmap.o regcache.o regcache-indexed.o regcache-rbtree.o
 obj-$(CONFIG_DEBUG_FS) += regmap-debugfs.o
 obj-$(CONFIG_REGMAP_I2C) += regmap-i2c.o
 obj-$(CONFIG_REGMAP_SPI) += regmap-spi.o
diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h
index 5bd5759efd5c..7ef8afc77e7c 100644
--- a/drivers/base/regmap/internal.h
+++ b/drivers/base/regmap/internal.h
@@ -119,4 +119,5 @@ int regcache_insert_reg(struct regmap *map, unsigned int reg,
                         unsigned int val);
 
 extern struct regcache_ops regcache_indexed_ops;
+extern struct regcache_ops regcache_rbtree_ops;
 #endif
diff --git a/drivers/base/regmap/regcache-rbtree.c b/drivers/base/regmap/regcache-rbtree.c
new file mode 100644
index 000000000000..4d7ba4511755
--- /dev/null
+++ b/drivers/base/regmap/regcache-rbtree.c
@@ -0,0 +1,399 @@
+/*
+ * 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;
+        /* number of bytes needed to represent the register index */
+        unsigned int word_size;
+        /* 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 val;
+
+        switch (rbnode->word_size) {
+        case 1: {
+                u8 *p = rbnode->block;
+                val = p[idx];
+                return val;
+        }
+        case 2: {
+                u16 *p = rbnode->block;
+                val = p[idx];
+                return val;
+        }
+        default:
+                BUG();
+                break;
+        }
+        return -1;
+}
+
+static void regcache_rbtree_set_register(struct regcache_rbtree_node *rbnode,
+                                         unsigned int idx, unsigned int val)
+{
+        switch (rbnode->word_size) {
+        case 1: {
+                u8 *p = rbnode->block;
+                p[idx] = val;
+                break;
+        }
+        case 2: {
+                u16 *p = rbnode->block;
+                p[idx] = val;
+                break;
+        }
+        default:
+                BUG();
+                break;
+        }
+}
+
+static struct regcache_rbtree_node *regcache_rbtree_lookup(
+        struct rb_root *root, unsigned int reg)
+{
+        struct rb_node *node;
+        struct regcache_rbtree_node *rbnode;
+        unsigned int base_reg, top_reg;
+
+        node = 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)
+                        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_ctx *rbtree_ctx;
+        struct regcache_rbtree_node *rbnode;
+        unsigned int base_reg, top_reg;
+        unsigned int reg_tmp;
+
+        rbtree_ctx = map->cache;
+        /* look up the required register in the cached rbnode */
+        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) {
+                        reg_tmp = reg - base_reg;
+                        *value = regcache_rbtree_get_register(rbnode, reg_tmp);
+                        return 0;
+                }
+        }
+        /* if we can't locate it in the cached rbnode we'll have
+         * to traverse the rbtree looking for it.
+         */
+        rbnode = regcache_rbtree_lookup(&rbtree_ctx->root, reg);
+        if (rbnode) {
+                reg_tmp = reg - rbnode->base_reg;
+                *value = regcache_rbtree_get_register(rbnode, reg_tmp);
+                rbtree_ctx->cached_rbnode = rbnode;
+        } else {
+                /* uninitialized registers default to 0 */
+                *value = 0;
+        }
+
+        return 0;
+}
+
+
+static int regcache_rbtree_insert_to_block(struct regcache_rbtree_node *rbnode,
+                                           unsigned int pos, unsigned int reg,
+                                           unsigned int value)
+{
+        u8 *blk;
+
+        blk = krealloc(rbnode->block,
+                       (rbnode->blklen + 1) * rbnode->word_size, GFP_KERNEL);
+        if (!blk)
+                return -ENOMEM;
+
+        /* insert the register value in the correct place in the rbnode block */
+        memmove(blk + (pos + 1) * rbnode->word_size,
+                blk + pos * rbnode->word_size,
+                (rbnode->blklen - pos) * rbnode->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);
+        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 base_reg, top_reg;
+        unsigned int pos;
+        int i;
+        int ret;
+
+        rbtree_ctx = map->cache;
+        /* look up the required register in the cached rbnode */
+        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) {
+                        reg_tmp = reg - base_reg;
+                        val = regcache_rbtree_get_register(rbnode, reg_tmp);
+                        if (val == value)
+                                return 0;
+                        regcache_rbtree_set_register(rbnode, reg_tmp, value);
+                        return 0;
+                }
+        }
+        /* if we can't locate it in the cached rbnode we'll have
+         * to traverse the rbtree looking for it.
+         */
+        rbnode = regcache_rbtree_lookup(&rbtree_ctx->root, reg);
+        if (rbnode) {
+                reg_tmp = reg - rbnode->base_reg;
+                val = regcache_rbtree_get_register(rbnode, reg_tmp);
+                if (val == value)
+                        return 0;
+                regcache_rbtree_set_register(rbnode, reg_tmp, value);
+                rbtree_ctx->cached_rbnode = rbnode;
+        } else {
+                /* bail out early, no need to create the rbnode yet */
+                if (!value)
+                        return 0;
+                /* 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);
+                                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->word_size = map->cache_word_size;
+                rbnode->block = kmalloc(rbnode->blklen * rbnode->word_size,
+                                        GFP_KERNEL);
+                if (!rbnode->block) {
+                        kfree(rbnode);
+                        return -ENOMEM;
+                }
+                regcache_rbtree_set_register(rbnode, 0, value);
+                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);
+                        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
+};
diff --git a/drivers/base/regmap/regcache.c b/drivers/base/regmap/regcache.c
index 22b73ec12fd5..b870a668b771 100644
--- a/drivers/base/regmap/regcache.c
+++ b/drivers/base/regmap/regcache.c
@@ -17,6 +17,7 @@
 
 static const struct regcache_ops *cache_types[] = {
         &regcache_indexed_ops,
+        &regcache_rbtree_ops,
 };
 
 static int regcache_hw_init(struct regmap *map)
diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index ae6d3a4cee97..63c4a5e126e9 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -24,6 +24,7 @@ struct spi_device;
 enum regcache_type {
         REGCACHE_NONE,
         REGCACHE_INDEXED,
+        REGCACHE_RBTREE,
 };
 
 /**