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regmap: Optimize the lookup path to use binary search 

Since there are more lookups than insertions in a typical
scenario, optimize the linear search into a binary search.  For
this to work, we need to keep reg_defaults sorted upon
insertions, for now be lazy and use sort().

Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
This commit is contained in:
Dimitris Papastamos 2011-10-03 10:50:14 +01:00 committed by Mark Brown
parent ac77a765cb
commit c08604b8ae
1 changed files with 23 additions and 4 deletions
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27
drivers/base/regmap/regcache.c
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@ -12,6 +12,7 @@
#include <linux/slab.h>
#include <trace/events/regmap.h>
#include <linux/sort.h>
#include "internal.h"
@ -356,14 +357,30 @@ unsigned int regcache_get_val(const void *base, unsigned int idx,
int regcache_lookup_reg(struct regmap *map, unsigned int reg)
{
unsigned int i;
unsigned int min, max, index;
for (i = 0; i < map->num_reg_defaults; i++)
if (map->reg_defaults[i].reg == reg)
return i;
min = 0;
max = map->num_reg_defaults - 1;
do {
index = (min + max) / 2;
if (map->reg_defaults[index].reg == reg)
return index;
if (map->reg_defaults[index].reg < reg)
min = index + 1;
else
max = index;
} while (min <= max);
return -1;
}
static int regcache_insert_cmp(const void *a, const void *b)
{
const struct reg_default *_a = a;
const struct reg_default *_b = b;
return _a->reg - _b->reg;
}
int regcache_insert_reg(struct regmap *map, unsigned int reg,
unsigned int val)
{
@ -378,5 +395,7 @@ int regcache_insert_reg(struct regmap *map, unsigned int reg,
map->num_reg_defaults++;
map->reg_defaults[map->num_reg_defaults - 1].reg = reg;
map->reg_defaults[map->num_reg_defaults - 1].def = val;
sort(map->reg_defaults, map->num_reg_defaults,
sizeof(struct reg_default), regcache_insert_cmp, NULL);
return 0;
}