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linux-sg2042/drivers/base/regmap/regcache-flat.c

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regmap: flat: Add flat cache type While for I2C and SPI devices the overhead of using rbtree for devices with only one block of registers is negligible the same isn't always going to be true for MMIO devices where the I/O costs are very much lower. Cater for these devices by adding a simple flat array type for them where the lookups are simple array accesses, taking us right back to the original ASoC cache implementation. Thanks to Magnus Damm for the discussion which prompted this. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2012-12-19 22:51:55 +08:00
/*
* Register cache access API - flat caching support
*
* Copyright 2012 Wolfson Microelectronics plc
*
* Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
*
* 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 <linux/device.h>
#include <linux/seq_file.h>
regmap: cache: Sort include headers alphabetically If the inlcude headers aren't sorted alphabetically, then the logical choice is to append new ones, however that creates a lot of potential for conflicts or duplicates because every change will then add new includes in the same location. Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com> Signed-off-by: Mark Brown <broonie@kernel.org>
2014-10-09 17:02:52 +08:00
#include <linux/slab.h>
regmap: flat: Add flat cache type While for I2C and SPI devices the overhead of using rbtree for devices with only one block of registers is negligible the same isn't always going to be true for MMIO devices where the I/O costs are very much lower. Cater for these devices by adding a simple flat array type for them where the lookups are simple array accesses, taking us right back to the original ASoC cache implementation. Thanks to Magnus Damm for the discussion which prompted this. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2012-12-19 22:51:55 +08:00
#include "internal.h"
regcache: flat: Introduce register strider order Here we introduce regcache_flat_get_index(), which using register stride order and bit rotation, will save some memory spaces for flat cache. Though this will also lost some access performance, since the bit rotation is used to get the index of the cache array, and this could be ingored for memory I/O accessing. Signed-off-by: Xiubo Li <lixiubo@cmss.chinamobile.com> Signed-off-by: Mark Brown <broonie@kernel.org>
2016-01-04 18:00:35 +08:00
static inline unsigned int regcache_flat_get_index(const struct regmap *map,
unsigned int reg)
{
return regcache_get_index_by_order(map, reg);
}
regmap: flat: Add flat cache type While for I2C and SPI devices the overhead of using rbtree for devices with only one block of registers is negligible the same isn't always going to be true for MMIO devices where the I/O costs are very much lower. Cater for these devices by adding a simple flat array type for them where the lookups are simple array accesses, taking us right back to the original ASoC cache implementation. Thanks to Magnus Damm for the discussion which prompted this. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2012-12-19 22:51:55 +08:00
static int regcache_flat_init(struct regmap *map)
{
int i;
unsigned int *cache;
regcache: flat: Require max_registers to be set If max_register is unset, regcache_flat_get_index will return 0 and only memory for 1 unsigned int will be allocated, resulting in writing out of bounds. Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com> Signed-off-by: Mark Brown <broonie@kernel.org>
2016-03-29 14:53:32 +08:00
if (!map || map->reg_stride_order < 0 || !map->max_register)
regcache: flat: Introduce register strider order Here we introduce regcache_flat_get_index(), which using register stride order and bit rotation, will save some memory spaces for flat cache. Though this will also lost some access performance, since the bit rotation is used to get the index of the cache array, and this could be ingored for memory I/O accessing. Signed-off-by: Xiubo Li <lixiubo@cmss.chinamobile.com> Signed-off-by: Mark Brown <broonie@kernel.org>
2016-01-04 18:00:35 +08:00
return -EINVAL;
map->cache = kcalloc(regcache_flat_get_index(map, map->max_register)
+ 1, sizeof(unsigned int), GFP_KERNEL);
regmap: flat: Add flat cache type While for I2C and SPI devices the overhead of using rbtree for devices with only one block of registers is negligible the same isn't always going to be true for MMIO devices where the I/O costs are very much lower. Cater for these devices by adding a simple flat array type for them where the lookups are simple array accesses, taking us right back to the original ASoC cache implementation. Thanks to Magnus Damm for the discussion which prompted this. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2012-12-19 22:51:55 +08:00
if (!map->cache)
return -ENOMEM;
cache = map->cache;
for (i = 0; i < map->num_reg_defaults; i++)
regcache: flat: Introduce register strider order Here we introduce regcache_flat_get_index(), which using register stride order and bit rotation, will save some memory spaces for flat cache. Though this will also lost some access performance, since the bit rotation is used to get the index of the cache array, and this could be ingored for memory I/O accessing. Signed-off-by: Xiubo Li <lixiubo@cmss.chinamobile.com> Signed-off-by: Mark Brown <broonie@kernel.org>
2016-01-04 18:00:35 +08:00
cache[regcache_flat_get_index(map, map->reg_defaults[i].reg)] =
map->reg_defaults[i].def;
regmap: flat: Add flat cache type While for I2C and SPI devices the overhead of using rbtree for devices with only one block of registers is negligible the same isn't always going to be true for MMIO devices where the I/O costs are very much lower. Cater for these devices by adding a simple flat array type for them where the lookups are simple array accesses, taking us right back to the original ASoC cache implementation. Thanks to Magnus Damm for the discussion which prompted this. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2012-12-19 22:51:55 +08:00
return 0;
}
static int regcache_flat_exit(struct regmap *map)
{
kfree(map->cache);
map->cache = NULL;
return 0;
}
static int regcache_flat_read(struct regmap *map,
unsigned int reg, unsigned int *value)
{
unsigned int *cache = map->cache;
regcache: flat: Introduce register strider order Here we introduce regcache_flat_get_index(), which using register stride order and bit rotation, will save some memory spaces for flat cache. Though this will also lost some access performance, since the bit rotation is used to get the index of the cache array, and this could be ingored for memory I/O accessing. Signed-off-by: Xiubo Li <lixiubo@cmss.chinamobile.com> Signed-off-by: Mark Brown <broonie@kernel.org>
2016-01-04 18:00:35 +08:00
*value = cache[regcache_flat_get_index(map, reg)];
regmap: flat: Add flat cache type While for I2C and SPI devices the overhead of using rbtree for devices with only one block of registers is negligible the same isn't always going to be true for MMIO devices where the I/O costs are very much lower. Cater for these devices by adding a simple flat array type for them where the lookups are simple array accesses, taking us right back to the original ASoC cache implementation. Thanks to Magnus Damm for the discussion which prompted this. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2012-12-19 22:51:55 +08:00
return 0;
}
static int regcache_flat_write(struct regmap *map, unsigned int reg,
unsigned int value)
{
unsigned int *cache = map->cache;
regcache: flat: Introduce register strider order Here we introduce regcache_flat_get_index(), which using register stride order and bit rotation, will save some memory spaces for flat cache. Though this will also lost some access performance, since the bit rotation is used to get the index of the cache array, and this could be ingored for memory I/O accessing. Signed-off-by: Xiubo Li <lixiubo@cmss.chinamobile.com> Signed-off-by: Mark Brown <broonie@kernel.org>
2016-01-04 18:00:35 +08:00
cache[regcache_flat_get_index(map, reg)] = value;
regmap: flat: Add flat cache type While for I2C and SPI devices the overhead of using rbtree for devices with only one block of registers is negligible the same isn't always going to be true for MMIO devices where the I/O costs are very much lower. Cater for these devices by adding a simple flat array type for them where the lookups are simple array accesses, taking us right back to the original ASoC cache implementation. Thanks to Magnus Damm for the discussion which prompted this. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2012-12-19 22:51:55 +08:00
return 0;
}
struct regcache_ops regcache_flat_ops = {
.type = REGCACHE_FLAT,
.name = "flat",
.init = regcache_flat_init,
.exit = regcache_flat_exit,
.read = regcache_flat_read,
.write = regcache_flat_write,
};