--- /dev/null
+/*
+ * 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
+};
projects / GitHub / LineageOS / G12 / android_kernel_amlogic_linux-4.9.git / commitdiff