regmap: rbtree: Use range information to allocate nodes

If range information has been provided then when we allocate a rbnode
within a range allocate the entire range. The goal is to minimise the
number of reallocations done when combining or extending blocks. At
present only readability and yes_ranges are taken into account, this is
expected to cover most cases efficiently.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

diff --git a/drivers/base/regmap/regcache-rbtree.c b/drivers/base/regmap/regcache-rbtree.c
index 3a00014..4e131c5 100644 (file)
--- a/drivers/base/regmap/regcache-rbtree.c
+++ b/drivers/base/regmap/regcache-rbtree.c
@@ -308,13 +308,34 @@ 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), GFP_KERNEL);
        if (!rbnode)
                return NULL;
 
-       rbnode->blklen = sizeof(*rbnode);
-       rbnode->base_reg = reg;
+       /* 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
+                               + 1;
+                       rbnode->base_reg = range->range_min;
+               }
+       }
+
+       if (!rbnode->blklen) {
+               rbnode->blklen = sizeof(*rbnode);
+               rbnode->base_reg = reg;
+       }
+
        rbnode->block = kmalloc(rbnode->blklen * map->cache_word_size,
                                GFP_KERNEL);
        if (!rbnode->block) {