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Commit c08604b8 authored by Dimitris Papastamos's avatar Dimitris Papastamos Committed by Mark Brown
Browse files

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: default avatarDimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: default avatarMark Brown <broonie@opensource.wolfsonmicro.com>
parent ac77a765

drivers/base/regmap/regcache.c

+24 −5
Original line number Diff line number Diff line
@@ -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;



	for (i = 0; i < map->num_reg_defaults; i++)

		if (map->reg_defaults[i].reg == reg)

			return i;

	unsigned int min, max, index;



	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;

}