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>

diff --git a/drivers/base/regmap/Makefile b/drivers/base/regmap/Makefile
index 5e75d1b683e236cf8ecc35a5c6f9b28ced8d30f3..cf129980abd0b2637f02acd446b2882d787751fd 100644 (file)
--- a/drivers/base/regmap/Makefile
+++ b/drivers/base/regmap/Makefile
@@ -1,5 +1,5 @@
 obj-$(CONFIG_REGMAP) += regmap.o regcache.o
-obj-$(CONFIG_REGMAP) += regcache-rbtree.o regcache-lzo.o
+obj-$(CONFIG_REGMAP) += regcache-rbtree.o regcache-lzo.o regcache-flat.o
 obj-$(CONFIG_DEBUG_FS) += regmap-debugfs.o
 obj-$(CONFIG_REGMAP_I2C) += regmap-i2c.o
 obj-$(CONFIG_REGMAP_SPI) += regmap-spi.o

diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h
index 401d1919635a5fcdf9bac6b84d99ffdc485d0e14..e22bb80edff145707ff489504d9453eead87cdcb 100644 (file)
--- a/drivers/base/regmap/internal.h
+++ b/drivers/base/regmap/internal.h
@@ -177,5 +177,6 @@ int regcache_lookup_reg(struct regmap *map, unsigned int reg);
 
 extern struct regcache_ops regcache_rbtree_ops;
 extern struct regcache_ops regcache_lzo_ops;
+extern struct regcache_ops regcache_flat_ops;
 
 #endif

diff --git a/drivers/base/regmap/regcache-flat.c b/drivers/base/regmap/regcache-flat.c
new file mode 100644 (file)
index 0000000..d9762e4
--- /dev/null
+++ b/drivers/base/regmap/regcache-flat.c
@@ -0,0 +1,72 @@
+/*
+ * 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/slab.h>
+#include <linux/device.h>
+#include <linux/seq_file.h>
+
+#include "internal.h"
+
+static int regcache_flat_init(struct regmap *map)
+{
+       int i;
+       unsigned int *cache;
+
+       map->cache = kzalloc(sizeof(unsigned int) * (map->max_register + 1),
+                            GFP_KERNEL);
+       if (!map->cache)
+               return -ENOMEM;
+
+       cache = map->cache;
+
+       for (i = 0; i < map->num_reg_defaults; i++)
+               cache[map->reg_defaults[i].reg] = map->reg_defaults[i].def;
+
+       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;
+
+       *value = cache[reg];
+
+       return 0;
+}
+
+static int regcache_flat_write(struct regmap *map, unsigned int reg,
+                              unsigned int value)
+{
+       unsigned int *cache = map->cache;
+
+       cache[reg] = value;
+
+       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,
+};

diff --git a/drivers/base/regmap/regcache.c b/drivers/base/regmap/regcache.c
index 835883bda977c27cdeb1d5ec45e63a6e69c47269..e69ff3e4742c262eceda875b10cc384af8149496 100644 (file)
--- a/drivers/base/regmap/regcache.c
+++ b/drivers/base/regmap/regcache.c
@@ -22,6 +22,7 @@
 static const struct regcache_ops *cache_types[] = {
        &regcache_rbtree_ops,
        &regcache_lzo_ops,
+       &regcache_flat_ops,
 };
 
 static int regcache_hw_init(struct regmap *map)

diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index b7e95bf942c9ce8936f61c61efb0261f9c09ad37..390d879d473a41f05e5feddc5c43115138dd1815 100644 (file)
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -28,7 +28,8 @@ struct regmap_range_cfg;
 enum regcache_type {
        REGCACHE_NONE,
        REGCACHE_RBTREE,
-       REGCACHE_COMPRESSED
+       REGCACHE_COMPRESSED,
+       REGCACHE_FLAT,
 };
 
 /**