/* * Register cache access API - rbtree caching support * * Copyright 2011 Wolfson Microelectronics plc * * Author: Dimitris Papastamos * * 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 #include #include #include #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 { /* the actual rbtree node holding this block */ struct rb_node node; /* base register handled by this block */ unsigned int base_reg; /* 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 word_size) { return regcache_get_val(rbnode->block, idx, word_size); } static void regcache_rbtree_set_register(struct regcache_rbtree_node *rbnode, unsigned int idx, unsigned int val, unsigned int word_size) { regcache_set_val(rbnode->block, idx, val, word_size); } 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(rbnode, &base_reg, &top_reg); if (reg >= base_reg && reg <= top_reg) return rbnode; } node = rbtree_ctx->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) { 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 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; } #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; int nodes = 0; int registers = 0; mutex_lock(&map->lock); for (node = rb_first(&rbtree_ctx->root); node != NULL; node = rb_next(node)) { n = container_of(node, struct regcache_rbtree_node, node); regcache_rbtree_get_base_top_reg(n, &base, &top); seq_printf(s, "%x-%x (%d)\n", base, top, top - base + 1); nodes++; registers += top - base + 1; } seq_printf(s, "%d nodes, %d registers, average %d registers\n", nodes, registers, registers / nodes); mutex_unlock(&map->lock); return 0; } static int rbtree_open(struct inode *inode, struct file *file) { return single_open(file, rbtree_show, inode->i_private); } static const struct file_operations rbtree_fops = { .open = rbtree_open, .read = seq_read, .llseek = seq_lseek, .release = single_release, }; static void rbtree_debugfs_init(struct regmap *map) { debugfs_create_file("rbtree", 0400, map->debugfs, map, &rbtree_fops); } #else static void rbtree_debugfs_init(struct regmap *map) { } #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; } rbtree_debugfs_init(map); 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->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; *value = regcache_rbtree_get_register(rbnode, reg_tmp, map->cache_word_size); } else { return -ENOENT; } return 0; } static int regcache_rbtree_insert_to_block(struct regcache_rbtree_node *rbnode, unsigned int pos, unsigned int reg, unsigned int value, unsigned int word_size) { u8 *blk; blk = krealloc(rbnode->block, (rbnode->blklen + 1) * word_size, GFP_KERNEL); if (!blk) return -ENOMEM; /* insert the register value in the correct place in the rbnode block */ memmove(blk + (pos + 1) * word_size, blk + pos * word_size, (rbnode->blklen - pos) * 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, word_size); 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 pos; int i; 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; val = regcache_rbtree_get_register(rbnode, reg_tmp, map->cache_word_size); if (val == value) return 0; regcache_rbtree_set_register(rbnode, reg_tmp, value, map->cache_word_size); } else { /* 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, map->cache_word_size); 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->block = kmalloc(rbnode->blklen * map->cache_word_size, GFP_KERNEL); if (!rbnode->block) { kfree(rbnode); return -ENOMEM; } regcache_rbtree_set_register(rbnode, 0, value, map->cache_word_size); 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; 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, map->cache_word_size); /* Is this the hardware default? If so skip. */ ret = regcache_lookup_reg(map, i); if (ret > 0 && val == map->reg_defaults[ret].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 };