diff options
Diffstat (limited to 'drivers/base/regmap/regcache-rbtree.c')
| -rw-r--r-- | drivers/base/regmap/regcache-rbtree.c | 554 |
1 files changed, 554 insertions, 0 deletions
diff --git a/drivers/base/regmap/regcache-rbtree.c b/drivers/base/regmap/regcache-rbtree.c new file mode 100644 index 000000000..d65715b9e --- /dev/null +++ b/drivers/base/regmap/regcache-rbtree.c @@ -0,0 +1,554 @@ +// SPDX-License-Identifier: GPL-2.0 +// +// Register cache access API - rbtree caching support +// +// Copyright 2011 Wolfson Microelectronics plc +// +// Author: Dimitris Papastamos <dp@opensource.wolfsonmicro.com> + +#include <linux/debugfs.h> +#include <linux/device.h> +#include <linux/rbtree.h> +#include <linux/seq_file.h> +#include <linux/slab.h> + +#include "internal.h" + +static int regcache_rbtree_write(struct regmap *map, unsigned int reg, + unsigned int value); +static int regcache_rbtree_exit(struct regmap *map); + +struct regcache_rbtree_node { + /* block of adjacent registers */ + void *block; + /* Which registers are present */ + long *cache_present; + /* base register handled by this block */ + unsigned int base_reg; + /* number of registers available in the block */ + unsigned int blklen; + /* the actual rbtree node holding this block */ + struct rb_node node; +}; + +struct regcache_rbtree_ctx { + struct rb_root root; + struct regcache_rbtree_node *cached_rbnode; +}; + +static inline void regcache_rbtree_get_base_top_reg( + struct regmap *map, + struct regcache_rbtree_node *rbnode, + unsigned int *base, unsigned int *top) +{ + *base = rbnode->base_reg; + *top = rbnode->base_reg + ((rbnode->blklen - 1) * map->reg_stride); +} + +static unsigned int regcache_rbtree_get_register(struct regmap *map, + struct regcache_rbtree_node *rbnode, unsigned int idx) +{ + return regcache_get_val(map, rbnode->block, idx); +} + +static void regcache_rbtree_set_register(struct regmap *map, + struct regcache_rbtree_node *rbnode, + unsigned int idx, unsigned int val) +{ + set_bit(idx, rbnode->cache_present); + regcache_set_val(map, rbnode->block, idx, val); +} + +static struct regcache_rbtree_node *regcache_rbtree_lookup(struct regmap *map, + unsigned int reg) +{ + struct regcache_rbtree_ctx *rbtree_ctx = map->cache; + struct rb_node *node; + struct regcache_rbtree_node *rbnode; + unsigned int base_reg, top_reg; + + rbnode = rbtree_ctx->cached_rbnode; + if (rbnode) { + regcache_rbtree_get_base_top_reg(map, rbnode, &base_reg, + &top_reg); + if (reg >= base_reg && reg <= top_reg) + return rbnode; + } + + node = rbtree_ctx->root.rb_node; + while (node) { + rbnode = rb_entry(node, struct regcache_rbtree_node, node); + regcache_rbtree_get_base_top_reg(map, rbnode, &base_reg, + &top_reg); + if (reg >= base_reg && reg <= top_reg) { + rbtree_ctx->cached_rbnode = rbnode; + return rbnode; + } else if (reg > top_reg) { + node = node->rb_right; + } else if (reg < base_reg) { + node = node->rb_left; + } + } + + return NULL; +} + +static int regcache_rbtree_insert(struct regmap *map, 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 = rb_entry(*new, struct regcache_rbtree_node, node); + /* base and top registers of the current rbnode */ + regcache_rbtree_get_base_top_reg(map, 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; +} + +#ifdef CONFIG_DEBUG_FS +static int rbtree_show(struct seq_file *s, void *ignored) +{ + struct regmap *map = s->private; + struct regcache_rbtree_ctx *rbtree_ctx = map->cache; + struct regcache_rbtree_node *n; + struct rb_node *node; + unsigned int base, top; + size_t mem_size; + int nodes = 0; + int registers = 0; + int this_registers, average; + + map->lock(map->lock_arg); + + mem_size = sizeof(*rbtree_ctx); + + for (node = rb_first(&rbtree_ctx->root); node != NULL; + node = rb_next(node)) { + n = rb_entry(node, struct regcache_rbtree_node, node); + mem_size += sizeof(*n); + mem_size += (n->blklen * map->cache_word_size); + mem_size += BITS_TO_LONGS(n->blklen) * sizeof(long); + + regcache_rbtree_get_base_top_reg(map, n, &base, &top); + this_registers = ((top - base) / map->reg_stride) + 1; + seq_printf(s, "%x-%x (%d)\n", base, top, this_registers); + + nodes++; + registers += this_registers; + } + + if (nodes) + average = registers / nodes; + else + average = 0; + + seq_printf(s, "%d nodes, %d registers, average %d registers, used %zu bytes\n", + nodes, registers, average, mem_size); + + map->unlock(map->lock_arg); + + return 0; +} + +DEFINE_SHOW_ATTRIBUTE(rbtree); + +static void rbtree_debugfs_init(struct regmap *map) +{ + debugfs_create_file("rbtree", 0400, map->debugfs, map, &rbtree_fops); +} +#endif + +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_rbtree_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->cache_present); + kfree(rbtree_node->block); + kfree(rbtree_node); + } + + /* release the resources */ + kfree(map->cache); + map->cache = NULL; + + return 0; +} + +static int regcache_rbtree_read(struct regmap *map, + unsigned int reg, unsigned int *value) +{ + struct regcache_rbtree_node *rbnode; + unsigned int reg_tmp; + + rbnode = regcache_rbtree_lookup(map, reg); + if (rbnode) { + reg_tmp = (reg - rbnode->base_reg) / map->reg_stride; + if (!test_bit(reg_tmp, rbnode->cache_present)) + return -ENOENT; + *value = regcache_rbtree_get_register(map, rbnode, reg_tmp); + } else { + return -ENOENT; + } + + return 0; +} + + +static int regcache_rbtree_insert_to_block(struct regmap *map, + struct regcache_rbtree_node *rbnode, + unsigned int base_reg, + unsigned int top_reg, + unsigned int reg, + unsigned int value) +{ + unsigned int blklen; + unsigned int pos, offset; + unsigned long *present; + u8 *blk; + + blklen = (top_reg - base_reg) / map->reg_stride + 1; + pos = (reg - base_reg) / map->reg_stride; + offset = (rbnode->base_reg - base_reg) / map->reg_stride; + + blk = krealloc(rbnode->block, + blklen * map->cache_word_size, + map->alloc_flags); + if (!blk) + return -ENOMEM; + + rbnode->block = blk; + + if (BITS_TO_LONGS(blklen) > BITS_TO_LONGS(rbnode->blklen)) { + present = krealloc(rbnode->cache_present, + BITS_TO_LONGS(blklen) * sizeof(*present), + map->alloc_flags); + if (!present) + return -ENOMEM; + + memset(present + BITS_TO_LONGS(rbnode->blklen), 0, + (BITS_TO_LONGS(blklen) - BITS_TO_LONGS(rbnode->blklen)) + * sizeof(*present)); + } else { + present = rbnode->cache_present; + } + + /* insert the register value in the correct place in the rbnode block */ + if (pos == 0) { + memmove(blk + offset * map->cache_word_size, + blk, rbnode->blklen * map->cache_word_size); + bitmap_shift_left(present, present, offset, blklen); + } + + /* update the rbnode block, its size and the base register */ + rbnode->blklen = blklen; + rbnode->base_reg = base_reg; + rbnode->cache_present = present; + + regcache_rbtree_set_register(map, rbnode, pos, value); + return 0; +} + +static struct regcache_rbtree_node * +regcache_rbtree_node_alloc(struct regmap *map, unsigned int reg) +{ + struct regcache_rbtree_node *rbnode; + const struct regmap_range *range; + int i; + + rbnode = kzalloc(sizeof(*rbnode), map->alloc_flags); + if (!rbnode) + return NULL; + + /* If there is a read table then use it to guess at an allocation */ + if (map->rd_table) { + for (i = 0; i < map->rd_table->n_yes_ranges; i++) { + if (regmap_reg_in_range(reg, + &map->rd_table->yes_ranges[i])) + break; + } + + if (i != map->rd_table->n_yes_ranges) { + range = &map->rd_table->yes_ranges[i]; + rbnode->blklen = (range->range_max - range->range_min) / + map->reg_stride + 1; + rbnode->base_reg = range->range_min; + } + } + + if (!rbnode->blklen) { + rbnode->blklen = 1; + rbnode->base_reg = reg; + } + + rbnode->block = kmalloc_array(rbnode->blklen, map->cache_word_size, + map->alloc_flags); + if (!rbnode->block) + goto err_free; + + rbnode->cache_present = kcalloc(BITS_TO_LONGS(rbnode->blklen), + sizeof(*rbnode->cache_present), + map->alloc_flags); + if (!rbnode->cache_present) + goto err_free_block; + + return rbnode; + +err_free_block: + kfree(rbnode->block); +err_free: + kfree(rbnode); + return NULL; +} + +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 reg_tmp; + int ret; + + rbtree_ctx = map->cache; + + /* if we can't locate it in the cached rbnode we'll have + * to traverse the rbtree looking for it. + */ + rbnode = regcache_rbtree_lookup(map, reg); + if (rbnode) { + reg_tmp = (reg - rbnode->base_reg) / map->reg_stride; + regcache_rbtree_set_register(map, rbnode, reg_tmp, value); + } else { + unsigned int base_reg, top_reg; + unsigned int new_base_reg, new_top_reg; + unsigned int min, max; + unsigned int max_dist; + unsigned int dist, best_dist = UINT_MAX; + + max_dist = map->reg_stride * sizeof(*rbnode_tmp) / + map->cache_word_size; + if (reg < max_dist) + min = 0; + else + min = reg - max_dist; + max = reg + max_dist; + + /* look for an adjacent register to the one we are about to add */ + node = rbtree_ctx->root.rb_node; + while (node) { + rbnode_tmp = rb_entry(node, struct regcache_rbtree_node, + node); + + regcache_rbtree_get_base_top_reg(map, rbnode_tmp, + &base_reg, &top_reg); + + if (base_reg <= max && top_reg >= min) { + if (reg < base_reg) + dist = base_reg - reg; + else if (reg > top_reg) + dist = reg - top_reg; + else + dist = 0; + if (dist < best_dist) { + rbnode = rbnode_tmp; + best_dist = dist; + new_base_reg = min(reg, base_reg); + new_top_reg = max(reg, top_reg); + } + } + + /* + * Keep looking, we want to choose the closest block, + * otherwise we might end up creating overlapping + * blocks, which breaks the rbtree. + */ + if (reg < base_reg) + node = node->rb_left; + else if (reg > top_reg) + node = node->rb_right; + else + break; + } + + if (rbnode) { + ret = regcache_rbtree_insert_to_block(map, rbnode, + new_base_reg, + new_top_reg, reg, + value); + if (ret) + return ret; + rbtree_ctx->cached_rbnode = rbnode; + return 0; + } + + /* We did not manage to find a place to insert it in + * an existing block so create a new rbnode. + */ + rbnode = regcache_rbtree_node_alloc(map, reg); + if (!rbnode) + return -ENOMEM; + regcache_rbtree_set_register(map, rbnode, + (reg - rbnode->base_reg) / map->reg_stride, + value); + regcache_rbtree_insert(map, &rbtree_ctx->root, rbnode); + rbtree_ctx->cached_rbnode = rbnode; + } + + return 0; +} + +static int regcache_rbtree_sync(struct regmap *map, unsigned int min, + unsigned int max) +{ + struct regcache_rbtree_ctx *rbtree_ctx; + struct rb_node *node; + struct regcache_rbtree_node *rbnode; + unsigned int base_reg, top_reg; + unsigned int start, end; + int ret; + + 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); + + regcache_rbtree_get_base_top_reg(map, rbnode, &base_reg, + &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; + + ret = regcache_sync_block(map, rbnode->block, + rbnode->cache_present, + rbnode->base_reg, start, end); + if (ret != 0) + return ret; + } + + return regmap_async_complete(map); +} + +static int regcache_rbtree_drop(struct regmap *map, unsigned int min, + unsigned int max) +{ + struct regcache_rbtree_ctx *rbtree_ctx; + struct regcache_rbtree_node *rbnode; + struct rb_node *node; + unsigned int base_reg, top_reg; + unsigned int start, end; + + 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); + + regcache_rbtree_get_base_top_reg(map, rbnode, &base_reg, + &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, +}; |