1 files changed, 91 insertions, 11 deletions

diff --git a/drivers/base/regmap/regcache-flat.c b/drivers/base/regmap/regcache-flat.c
index f36d3618b67c..86f7679175b1 100644
--- a/drivers/base/regmap/regcache-flat.c
+++ b/drivers/base/regmap/regcache-flat.c
@@ -6,7 +6,11 @@
 //
 // Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
 
+#include <linux/bitmap.h>
+#include <linux/bitops.h>
 #include <linux/device.h>
+#include <linux/limits.h>
+#include <linux/overflow.h>
 #include <linux/seq_file.h>
 #include <linux/slab.h>
 
@@ -18,34 +22,62 @@ static inline unsigned int regcache_flat_get_index(const struct regmap *map,
 	return regcache_get_index_by_order(map, reg);
 }
 
+struct regcache_flat_data {
+	unsigned long *valid;
+	unsigned int data[];
+};
+
 static int regcache_flat_init(struct regmap *map)
 {
 	int i;
-	unsigned int *cache;
+	size_t cache_data_size;
+	unsigned int cache_size;
+	struct regcache_flat_data *cache;
 
 	if (!map || map->reg_stride_order < 0 || !map->max_register_is_set)
 		return -EINVAL;
 
-	map->cache = kcalloc(regcache_flat_get_index(map, map->max_register)
-			     + 1, sizeof(unsigned int), map->alloc_flags);
-	if (!map->cache)
+	cache_size = regcache_flat_get_index(map, map->max_register) + 1;
+	cache_data_size = struct_size(cache, data, cache_size);
+
+	if (cache_data_size == SIZE_MAX) {
+		dev_err(map->dev, "cannot allocate regmap cache");
 		return -ENOMEM;
+	}
 
-	cache = map->cache;
+	cache = kzalloc(cache_data_size, map->alloc_flags);
+	if (!cache)
+		return -ENOMEM;
+
+	cache->valid = bitmap_zalloc(cache_size, map->alloc_flags);
+	if (!cache->valid)
+		goto err_free;
+
+	map->cache = cache;
 
 	for (i = 0; i < map->num_reg_defaults; i++) {
 		unsigned int reg = map->reg_defaults[i].reg;
 		unsigned int index = regcache_flat_get_index(map, reg);
 
-		cache[index] = map->reg_defaults[i].def;
+		cache->data[index] = map->reg_defaults[i].def;
+		__set_bit(index, cache->valid);
 	}
 
 	return 0;
+
+err_free:
+	kfree(cache);
+	return -ENOMEM;
 }
 
 static int regcache_flat_exit(struct regmap *map)
 {
-	kfree(map->cache);
+	struct regcache_flat_data *cache = map->cache;
+
+	if (cache)
+		bitmap_free(cache->valid);
+
+	kfree(cache);
 	map->cache = NULL;
 
 	return 0;
@@ -54,10 +86,24 @@ static int regcache_flat_exit(struct regmap *map)
 static int regcache_flat_read(struct regmap *map,
 			      unsigned int reg, unsigned int *value)
 {
-	unsigned int *cache = map->cache;
+	struct regcache_flat_data *cache = map->cache;
 	unsigned int index = regcache_flat_get_index(map, reg);
 
-	*value = cache[index];
+	*value = cache->data[index];
+
+	return 0;
+}
+
+static int regcache_flat_sparse_read(struct regmap *map,
+				     unsigned int reg, unsigned int *value)
+{
+	struct regcache_flat_data *cache = map->cache;
+	unsigned int index = regcache_flat_get_index(map, reg);
+
+	if (unlikely(!test_bit(index, cache->valid)))
+		return -ENOENT;
+
+	*value = cache->data[index];
 
 	return 0;
 }
@@ -65,10 +111,34 @@ static int regcache_flat_read(struct regmap *map,
 static int regcache_flat_write(struct regmap *map, unsigned int reg,
 			       unsigned int value)
 {
-	unsigned int *cache = map->cache;
+	struct regcache_flat_data *cache = map->cache;
 	unsigned int index = regcache_flat_get_index(map, reg);
 
-	cache[index] = value;
+	cache->data[index] = value;
+
+	return 0;
+}
+
+static int regcache_flat_sparse_write(struct regmap *map, unsigned int reg,
+				      unsigned int value)
+{
+	struct regcache_flat_data *cache = map->cache;
+	unsigned int index = regcache_flat_get_index(map, reg);
+
+	cache->data[index] = value;
+	__set_bit(index, cache->valid);
+
+	return 0;
+}
+
+static int regcache_flat_drop(struct regmap *map, unsigned int min,
+			      unsigned int max)
+{
+	struct regcache_flat_data *cache = map->cache;
+	unsigned int bitmap_min = regcache_flat_get_index(map, min);
+	unsigned int bitmap_max = regcache_flat_get_index(map, max);
+
+	bitmap_clear(cache->valid, bitmap_min, bitmap_max + 1 - bitmap_min);
 
 	return 0;
 }
@@ -81,3 +151,13 @@ struct regcache_ops regcache_flat_ops = {
 	.read = regcache_flat_read,
 	.write = regcache_flat_write,
 };
+
+struct regcache_ops regcache_flat_sparse_ops = {
+	.type = REGCACHE_FLAT_S,
+	.name = "flat-sparse",
+	.init = regcache_flat_init,
+	.exit = regcache_flat_exit,
+	.read = regcache_flat_sparse_read,
+	.write = regcache_flat_sparse_write,
+	.drop = regcache_flat_drop,
+};