431 lines
11 KiB
C
431 lines
11 KiB
C
/*
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* Register cache access API - rbtree caching support
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*
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* Copyright 2011 Wolfson Microelectronics plc
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*
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* Author: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/slab.h>
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#include <linux/device.h>
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#include <linux/debugfs.h>
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#include <linux/rbtree.h>
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#include <linux/seq_file.h>
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#include "internal.h"
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static int regcache_rbtree_write(struct regmap *map, unsigned int reg,
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unsigned int value);
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static int regcache_rbtree_exit(struct regmap *map);
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struct regcache_rbtree_node {
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/* the actual rbtree node holding this block */
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struct rb_node node;
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/* base register handled by this block */
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unsigned int base_reg;
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/* block of adjacent registers */
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void *block;
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/* number of registers available in the block */
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unsigned int blklen;
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} __attribute__ ((packed));
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struct regcache_rbtree_ctx {
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struct rb_root root;
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struct regcache_rbtree_node *cached_rbnode;
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};
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static inline void regcache_rbtree_get_base_top_reg(
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struct regcache_rbtree_node *rbnode,
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unsigned int *base, unsigned int *top)
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{
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*base = rbnode->base_reg;
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*top = rbnode->base_reg + rbnode->blklen - 1;
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}
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static unsigned int regcache_rbtree_get_register(
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struct regcache_rbtree_node *rbnode, unsigned int idx,
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unsigned int word_size)
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{
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return regcache_get_val(rbnode->block, idx, word_size);
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}
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static void regcache_rbtree_set_register(struct regcache_rbtree_node *rbnode,
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unsigned int idx, unsigned int val,
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unsigned int word_size)
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{
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regcache_set_val(rbnode->block, idx, val, word_size);
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}
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static struct regcache_rbtree_node *regcache_rbtree_lookup(struct regmap *map,
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unsigned int reg)
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{
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struct regcache_rbtree_ctx *rbtree_ctx = map->cache;
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struct rb_node *node;
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struct regcache_rbtree_node *rbnode;
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unsigned int base_reg, top_reg;
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rbnode = rbtree_ctx->cached_rbnode;
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if (rbnode) {
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regcache_rbtree_get_base_top_reg(rbnode, &base_reg, &top_reg);
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if (reg >= base_reg && reg <= top_reg)
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return rbnode;
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}
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node = rbtree_ctx->root.rb_node;
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while (node) {
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rbnode = container_of(node, struct regcache_rbtree_node, node);
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regcache_rbtree_get_base_top_reg(rbnode, &base_reg, &top_reg);
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if (reg >= base_reg && reg <= top_reg) {
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rbtree_ctx->cached_rbnode = rbnode;
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return rbnode;
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} else if (reg > top_reg) {
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node = node->rb_right;
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} else if (reg < base_reg) {
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node = node->rb_left;
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}
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}
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return NULL;
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}
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static int regcache_rbtree_insert(struct rb_root *root,
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struct regcache_rbtree_node *rbnode)
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{
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struct rb_node **new, *parent;
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struct regcache_rbtree_node *rbnode_tmp;
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unsigned int base_reg_tmp, top_reg_tmp;
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unsigned int base_reg;
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parent = NULL;
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new = &root->rb_node;
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while (*new) {
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rbnode_tmp = container_of(*new, struct regcache_rbtree_node,
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node);
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/* base and top registers of the current rbnode */
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regcache_rbtree_get_base_top_reg(rbnode_tmp, &base_reg_tmp,
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&top_reg_tmp);
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/* base register of the rbnode to be added */
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base_reg = rbnode->base_reg;
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parent = *new;
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/* if this register has already been inserted, just return */
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if (base_reg >= base_reg_tmp &&
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base_reg <= top_reg_tmp)
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return 0;
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else if (base_reg > top_reg_tmp)
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new = &((*new)->rb_right);
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else if (base_reg < base_reg_tmp)
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new = &((*new)->rb_left);
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}
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/* insert the node into the rbtree */
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rb_link_node(&rbnode->node, parent, new);
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rb_insert_color(&rbnode->node, root);
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return 1;
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}
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#ifdef CONFIG_DEBUG_FS
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static int rbtree_show(struct seq_file *s, void *ignored)
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{
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struct regmap *map = s->private;
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struct regcache_rbtree_ctx *rbtree_ctx = map->cache;
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struct regcache_rbtree_node *n;
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struct rb_node *node;
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unsigned int base, top;
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int nodes = 0;
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int registers = 0;
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int average;
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mutex_lock(&map->lock);
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for (node = rb_first(&rbtree_ctx->root); node != NULL;
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node = rb_next(node)) {
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n = container_of(node, struct regcache_rbtree_node, node);
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regcache_rbtree_get_base_top_reg(n, &base, &top);
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seq_printf(s, "%x-%x (%d)\n", base, top, top - base + 1);
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nodes++;
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registers += top - base + 1;
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}
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if (nodes)
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average = registers / nodes;
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else
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average = 0;
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seq_printf(s, "%d nodes, %d registers, average %d registers\n",
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nodes, registers, average);
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mutex_unlock(&map->lock);
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return 0;
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}
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static int rbtree_open(struct inode *inode, struct file *file)
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{
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return single_open(file, rbtree_show, inode->i_private);
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}
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static const struct file_operations rbtree_fops = {
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.open = rbtree_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = single_release,
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};
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static void rbtree_debugfs_init(struct regmap *map)
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{
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debugfs_create_file("rbtree", 0400, map->debugfs, map, &rbtree_fops);
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}
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#else
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static void rbtree_debugfs_init(struct regmap *map)
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{
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}
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#endif
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static int regcache_rbtree_init(struct regmap *map)
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{
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struct regcache_rbtree_ctx *rbtree_ctx;
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int i;
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int ret;
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map->cache = kmalloc(sizeof *rbtree_ctx, GFP_KERNEL);
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if (!map->cache)
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return -ENOMEM;
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rbtree_ctx = map->cache;
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rbtree_ctx->root = RB_ROOT;
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rbtree_ctx->cached_rbnode = NULL;
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for (i = 0; i < map->num_reg_defaults; i++) {
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ret = regcache_rbtree_write(map,
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map->reg_defaults[i].reg,
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map->reg_defaults[i].def);
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if (ret)
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goto err;
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}
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rbtree_debugfs_init(map);
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return 0;
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err:
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regcache_rbtree_exit(map);
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return ret;
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}
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static int regcache_rbtree_exit(struct regmap *map)
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{
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struct rb_node *next;
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struct regcache_rbtree_ctx *rbtree_ctx;
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struct regcache_rbtree_node *rbtree_node;
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/* if we've already been called then just return */
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rbtree_ctx = map->cache;
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if (!rbtree_ctx)
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return 0;
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/* free up the rbtree */
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next = rb_first(&rbtree_ctx->root);
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while (next) {
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rbtree_node = rb_entry(next, struct regcache_rbtree_node, node);
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next = rb_next(&rbtree_node->node);
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rb_erase(&rbtree_node->node, &rbtree_ctx->root);
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kfree(rbtree_node->block);
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kfree(rbtree_node);
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}
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/* release the resources */
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kfree(map->cache);
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map->cache = NULL;
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return 0;
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}
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static int regcache_rbtree_read(struct regmap *map,
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unsigned int reg, unsigned int *value)
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{
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struct regcache_rbtree_node *rbnode;
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unsigned int reg_tmp;
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rbnode = regcache_rbtree_lookup(map, reg);
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if (rbnode) {
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reg_tmp = reg - rbnode->base_reg;
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*value = regcache_rbtree_get_register(rbnode, reg_tmp,
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map->cache_word_size);
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} else {
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return -ENOENT;
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}
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return 0;
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}
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static int regcache_rbtree_insert_to_block(struct regcache_rbtree_node *rbnode,
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unsigned int pos, unsigned int reg,
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unsigned int value, unsigned int word_size)
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{
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u8 *blk;
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blk = krealloc(rbnode->block,
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(rbnode->blklen + 1) * word_size, GFP_KERNEL);
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if (!blk)
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return -ENOMEM;
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/* insert the register value in the correct place in the rbnode block */
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memmove(blk + (pos + 1) * word_size,
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blk + pos * word_size,
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(rbnode->blklen - pos) * word_size);
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/* update the rbnode block, its size and the base register */
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rbnode->block = blk;
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rbnode->blklen++;
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if (!pos)
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rbnode->base_reg = reg;
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regcache_rbtree_set_register(rbnode, pos, value, word_size);
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return 0;
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}
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static int regcache_rbtree_write(struct regmap *map, unsigned int reg,
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unsigned int value)
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{
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struct regcache_rbtree_ctx *rbtree_ctx;
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struct regcache_rbtree_node *rbnode, *rbnode_tmp;
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struct rb_node *node;
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unsigned int val;
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unsigned int reg_tmp;
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unsigned int pos;
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int i;
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int ret;
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rbtree_ctx = map->cache;
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/* if we can't locate it in the cached rbnode we'll have
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* to traverse the rbtree looking for it.
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*/
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rbnode = regcache_rbtree_lookup(map, reg);
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if (rbnode) {
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reg_tmp = reg - rbnode->base_reg;
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val = regcache_rbtree_get_register(rbnode, reg_tmp,
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map->cache_word_size);
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if (val == value)
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return 0;
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regcache_rbtree_set_register(rbnode, reg_tmp, value,
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map->cache_word_size);
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} else {
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/* look for an adjacent register to the one we are about to add */
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for (node = rb_first(&rbtree_ctx->root); node;
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node = rb_next(node)) {
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rbnode_tmp = rb_entry(node, struct regcache_rbtree_node, node);
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for (i = 0; i < rbnode_tmp->blklen; i++) {
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reg_tmp = rbnode_tmp->base_reg + i;
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if (abs(reg_tmp - reg) != 1)
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continue;
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/* decide where in the block to place our register */
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if (reg_tmp + 1 == reg)
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pos = i + 1;
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else
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pos = i;
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ret = regcache_rbtree_insert_to_block(rbnode_tmp, pos,
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reg, value,
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map->cache_word_size);
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if (ret)
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return ret;
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rbtree_ctx->cached_rbnode = rbnode_tmp;
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return 0;
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}
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}
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/* we did not manage to find a place to insert it in an existing
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* block so create a new rbnode with a single register in its block.
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* This block will get populated further if any other adjacent
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* registers get modified in the future.
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*/
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rbnode = kzalloc(sizeof *rbnode, GFP_KERNEL);
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if (!rbnode)
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return -ENOMEM;
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rbnode->blklen = 1;
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rbnode->base_reg = reg;
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rbnode->block = kmalloc(rbnode->blklen * map->cache_word_size,
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GFP_KERNEL);
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if (!rbnode->block) {
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kfree(rbnode);
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return -ENOMEM;
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}
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regcache_rbtree_set_register(rbnode, 0, value, map->cache_word_size);
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regcache_rbtree_insert(&rbtree_ctx->root, rbnode);
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rbtree_ctx->cached_rbnode = rbnode;
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}
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return 0;
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}
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static int regcache_rbtree_sync(struct regmap *map, unsigned int min,
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unsigned int max)
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{
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struct regcache_rbtree_ctx *rbtree_ctx;
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struct rb_node *node;
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struct regcache_rbtree_node *rbnode;
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unsigned int regtmp;
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unsigned int val;
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int ret;
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int i, base, end;
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rbtree_ctx = map->cache;
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for (node = rb_first(&rbtree_ctx->root); node; node = rb_next(node)) {
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rbnode = rb_entry(node, struct regcache_rbtree_node, node);
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if (rbnode->base_reg < min)
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continue;
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if (rbnode->base_reg > max)
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break;
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if (rbnode->base_reg + rbnode->blklen < min)
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continue;
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if (min > rbnode->base_reg)
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base = min - rbnode->base_reg;
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else
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base = 0;
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if (max < rbnode->base_reg + rbnode->blklen)
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end = rbnode->base_reg + rbnode->blklen - max;
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else
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end = rbnode->blklen;
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for (i = base; i < end; i++) {
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regtmp = rbnode->base_reg + i;
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val = regcache_rbtree_get_register(rbnode, i,
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map->cache_word_size);
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/* Is this the hardware default? If so skip. */
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ret = regcache_lookup_reg(map, regtmp);
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if (ret >= 0 && val == map->reg_defaults[ret].def)
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continue;
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map->cache_bypass = 1;
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ret = _regmap_write(map, regtmp, val);
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map->cache_bypass = 0;
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if (ret)
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return ret;
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dev_dbg(map->dev, "Synced register %#x, value %#x\n",
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regtmp, val);
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}
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}
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return 0;
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}
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struct regcache_ops regcache_rbtree_ops = {
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.type = REGCACHE_RBTREE,
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.name = "rbtree",
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.init = regcache_rbtree_init,
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.exit = regcache_rbtree_exit,
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.read = regcache_rbtree_read,
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.write = regcache_rbtree_write,
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.sync = regcache_rbtree_sync
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};
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