555 lines
14 KiB
C
555 lines
14 KiB
C
// SPDX-License-Identifier: GPL-2.0
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//
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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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#include <linux/debugfs.h>
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#include <linux/device.h>
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#include <linux/rbtree.h>
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#include <linux/seq_file.h>
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#include <linux/slab.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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/* block of adjacent registers */
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void *block;
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/* Which registers are present */
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long *cache_present;
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/* base register handled by this block */
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unsigned int base_reg;
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/* number of registers available in the block */
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unsigned int blklen;
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/* the actual rbtree node holding this block */
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struct rb_node node;
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};
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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 regmap *map,
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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) * map->reg_stride);
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}
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static unsigned int regcache_rbtree_get_register(struct regmap *map,
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struct regcache_rbtree_node *rbnode, unsigned int idx)
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{
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return regcache_get_val(map, rbnode->block, idx);
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}
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static void regcache_rbtree_set_register(struct regmap *map,
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struct regcache_rbtree_node *rbnode,
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unsigned int idx, unsigned int val)
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{
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set_bit(idx, rbnode->cache_present);
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regcache_set_val(map, rbnode->block, idx, val);
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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(map, rbnode, &base_reg,
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&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 = rb_entry(node, struct regcache_rbtree_node, node);
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regcache_rbtree_get_base_top_reg(map, rbnode, &base_reg,
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&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 regmap *map, 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 = rb_entry(*new, struct regcache_rbtree_node, node);
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/* base and top registers of the current rbnode */
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regcache_rbtree_get_base_top_reg(map, 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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size_t mem_size;
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int nodes = 0;
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int registers = 0;
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int this_registers, average;
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map->lock(map->lock_arg);
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mem_size = sizeof(*rbtree_ctx);
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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 = rb_entry(node, struct regcache_rbtree_node, node);
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mem_size += sizeof(*n);
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mem_size += (n->blklen * map->cache_word_size);
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mem_size += BITS_TO_LONGS(n->blklen) * sizeof(long);
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regcache_rbtree_get_base_top_reg(map, n, &base, &top);
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this_registers = ((top - base) / map->reg_stride) + 1;
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seq_printf(s, "%x-%x (%d)\n", base, top, this_registers);
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nodes++;
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registers += this_registers;
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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, used %zu bytes\n",
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nodes, registers, average, mem_size);
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map->unlock(map->lock_arg);
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return 0;
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}
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DEFINE_SHOW_ATTRIBUTE(rbtree);
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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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#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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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->cache_present);
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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) / map->reg_stride;
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if (!test_bit(reg_tmp, rbnode->cache_present))
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return -ENOENT;
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*value = regcache_rbtree_get_register(map, rbnode, reg_tmp);
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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 regmap *map,
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struct regcache_rbtree_node *rbnode,
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unsigned int base_reg,
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unsigned int top_reg,
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unsigned int reg,
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unsigned int value)
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{
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unsigned int blklen;
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unsigned int pos, offset;
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unsigned long *present;
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u8 *blk;
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blklen = (top_reg - base_reg) / map->reg_stride + 1;
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pos = (reg - base_reg) / map->reg_stride;
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offset = (rbnode->base_reg - base_reg) / map->reg_stride;
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blk = krealloc(rbnode->block,
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blklen * map->cache_word_size,
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GFP_KERNEL);
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if (!blk)
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return -ENOMEM;
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if (BITS_TO_LONGS(blklen) > BITS_TO_LONGS(rbnode->blklen)) {
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present = krealloc(rbnode->cache_present,
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BITS_TO_LONGS(blklen) * sizeof(*present),
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GFP_KERNEL);
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if (!present) {
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kfree(blk);
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return -ENOMEM;
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}
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memset(present + BITS_TO_LONGS(rbnode->blklen), 0,
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(BITS_TO_LONGS(blklen) - BITS_TO_LONGS(rbnode->blklen))
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* sizeof(*present));
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} else {
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present = rbnode->cache_present;
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}
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/* insert the register value in the correct place in the rbnode block */
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if (pos == 0) {
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memmove(blk + offset * map->cache_word_size,
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blk, rbnode->blklen * map->cache_word_size);
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bitmap_shift_left(present, present, offset, blklen);
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}
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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 = blklen;
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rbnode->base_reg = base_reg;
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rbnode->cache_present = present;
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regcache_rbtree_set_register(map, rbnode, pos, value);
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return 0;
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}
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static struct regcache_rbtree_node *
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regcache_rbtree_node_alloc(struct regmap *map, unsigned int reg)
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{
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struct regcache_rbtree_node *rbnode;
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const struct regmap_range *range;
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int i;
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rbnode = kzalloc(sizeof(*rbnode), GFP_KERNEL);
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if (!rbnode)
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return NULL;
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/* If there is a read table then use it to guess at an allocation */
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if (map->rd_table) {
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for (i = 0; i < map->rd_table->n_yes_ranges; i++) {
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if (regmap_reg_in_range(reg,
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&map->rd_table->yes_ranges[i]))
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break;
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}
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if (i != map->rd_table->n_yes_ranges) {
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range = &map->rd_table->yes_ranges[i];
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rbnode->blklen = (range->range_max - range->range_min) /
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map->reg_stride + 1;
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rbnode->base_reg = range->range_min;
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}
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}
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if (!rbnode->blklen) {
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rbnode->blklen = 1;
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rbnode->base_reg = reg;
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}
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rbnode->block = kmalloc_array(rbnode->blklen, map->cache_word_size,
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GFP_KERNEL);
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if (!rbnode->block)
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goto err_free;
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rbnode->cache_present = kcalloc(BITS_TO_LONGS(rbnode->blklen),
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sizeof(*rbnode->cache_present),
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GFP_KERNEL);
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if (!rbnode->cache_present)
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goto err_free_block;
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return rbnode;
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err_free_block:
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kfree(rbnode->block);
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err_free:
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kfree(rbnode);
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return NULL;
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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 reg_tmp;
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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) / map->reg_stride;
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regcache_rbtree_set_register(map, rbnode, reg_tmp, value);
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} else {
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unsigned int base_reg, top_reg;
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unsigned int new_base_reg, new_top_reg;
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unsigned int min, max;
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unsigned int max_dist;
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unsigned int dist, best_dist = UINT_MAX;
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max_dist = map->reg_stride * sizeof(*rbnode_tmp) /
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map->cache_word_size;
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if (reg < max_dist)
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min = 0;
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else
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min = reg - max_dist;
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max = reg + max_dist;
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/* look for an adjacent register to the one we are about to add */
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node = rbtree_ctx->root.rb_node;
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while (node) {
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rbnode_tmp = rb_entry(node, struct regcache_rbtree_node,
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node);
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regcache_rbtree_get_base_top_reg(map, rbnode_tmp,
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&base_reg, &top_reg);
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if (base_reg <= max && top_reg >= min) {
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if (reg < base_reg)
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dist = base_reg - reg;
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else if (reg > top_reg)
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dist = reg - top_reg;
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else
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dist = 0;
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if (dist < best_dist) {
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rbnode = rbnode_tmp;
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best_dist = dist;
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new_base_reg = min(reg, base_reg);
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new_top_reg = max(reg, top_reg);
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}
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}
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/*
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* Keep looking, we want to choose the closest block,
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* otherwise we might end up creating overlapping
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* blocks, which breaks the rbtree.
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*/
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if (reg < base_reg)
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node = node->rb_left;
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else if (reg > top_reg)
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node = node->rb_right;
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else
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break;
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}
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if (rbnode) {
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ret = regcache_rbtree_insert_to_block(map, rbnode,
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new_base_reg,
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new_top_reg, reg,
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value);
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if (ret)
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return ret;
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rbtree_ctx->cached_rbnode = rbnode;
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return 0;
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}
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/* We did not manage to find a place to insert it in
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* an existing block so create a new rbnode.
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*/
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rbnode = regcache_rbtree_node_alloc(map, reg);
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if (!rbnode)
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return -ENOMEM;
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regcache_rbtree_set_register(map, rbnode,
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reg - rbnode->base_reg, value);
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regcache_rbtree_insert(map, &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 base_reg, top_reg;
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unsigned int start, end;
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int ret;
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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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regcache_rbtree_get_base_top_reg(map, rbnode, &base_reg,
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&top_reg);
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if (base_reg > max)
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break;
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if (top_reg < min)
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continue;
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if (min > base_reg)
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start = (min - base_reg) / map->reg_stride;
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else
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start = 0;
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if (max < top_reg)
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end = (max - base_reg) / map->reg_stride + 1;
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else
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end = rbnode->blklen;
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ret = regcache_sync_block(map, rbnode->block,
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rbnode->cache_present,
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rbnode->base_reg, start, end);
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if (ret != 0)
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return ret;
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}
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return regmap_async_complete(map);
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}
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static int regcache_rbtree_drop(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 regcache_rbtree_node *rbnode;
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struct rb_node *node;
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unsigned int base_reg, top_reg;
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unsigned int start, 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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regcache_rbtree_get_base_top_reg(map, rbnode, &base_reg,
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&top_reg);
|
|
if (base_reg > max)
|
|
break;
|
|
if (top_reg < min)
|
|
continue;
|
|
|
|
if (min > base_reg)
|
|
start = (min - base_reg) / map->reg_stride;
|
|
else
|
|
start = 0;
|
|
|
|
if (max < top_reg)
|
|
end = (max - base_reg) / map->reg_stride + 1;
|
|
else
|
|
end = rbnode->blklen;
|
|
|
|
bitmap_clear(rbnode->cache_present, start, end - start);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
struct regcache_ops regcache_rbtree_ops = {
|
|
.type = REGCACHE_RBTREE,
|
|
.name = "rbtree",
|
|
.init = regcache_rbtree_init,
|
|
.exit = regcache_rbtree_exit,
|
|
#ifdef CONFIG_DEBUG_FS
|
|
.debugfs_init = rbtree_debugfs_init,
|
|
#endif
|
|
.read = regcache_rbtree_read,
|
|
.write = regcache_rbtree_write,
|
|
.sync = regcache_rbtree_sync,
|
|
.drop = regcache_rbtree_drop,
|
|
};
|