regmap: introduce fast_io busses, and use a spinlock for them
Some bus types have very fast IO. For these, acquiring a mutex for every
IO operation is a significant overhead. Allow busses to indicate their IO
is fast, and enhance regmap to use a spinlock for those busses.
[Currently limited to native endian registers -- broonie]
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index bde30c5..6b4a775 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -158,6 +158,26 @@
return b[0];
}
+static void regmap_lock_mutex(struct regmap *map)
+{
+ mutex_lock(&map->mutex);
+}
+
+static void regmap_unlock_mutex(struct regmap *map)
+{
+ mutex_unlock(&map->mutex);
+}
+
+static void regmap_lock_spinlock(struct regmap *map)
+{
+ spin_lock(&map->spinlock);
+}
+
+static void regmap_unlock_spinlock(struct regmap *map)
+{
+ spin_unlock(&map->spinlock);
+}
+
/**
* regmap_init(): Initialise register map
*
@@ -187,7 +207,15 @@
goto err;
}
- mutex_init(&map->lock);
+ if (bus->fast_io) {
+ spin_lock_init(&map->spinlock);
+ map->lock = regmap_lock_spinlock;
+ map->unlock = regmap_unlock_spinlock;
+ } else {
+ mutex_init(&map->mutex);
+ map->lock = regmap_lock_mutex;
+ map->unlock = regmap_unlock_mutex;
+ }
map->format.buf_size = (config->reg_bits + config->val_bits) / 8;
map->format.reg_bytes = DIV_ROUND_UP(config->reg_bits, 8);
map->format.pad_bytes = config->pad_bits / 8;
@@ -365,7 +393,7 @@
{
int ret;
- mutex_lock(&map->lock);
+ map->lock(map);
regcache_exit(map);
regmap_debugfs_exit(map);
@@ -384,7 +412,7 @@
ret = regcache_init(map, config);
- mutex_unlock(&map->lock);
+ map->unlock(map);
return ret;
}
@@ -536,11 +564,11 @@
{
int ret;
- mutex_lock(&map->lock);
+ map->lock(map);
ret = _regmap_write(map, reg, val);
- mutex_unlock(&map->lock);
+ map->unlock(map);
return ret;
}
@@ -567,11 +595,11 @@
{
int ret;
- mutex_lock(&map->lock);
+ map->lock(map);
ret = _regmap_raw_write(map, reg, val, val_len);
- mutex_unlock(&map->lock);
+ map->unlock(map);
return ret;
}
@@ -601,7 +629,7 @@
if (!map->format.parse_val)
return -EINVAL;
- mutex_lock(&map->lock);
+ map->lock(map);
/* No formatting is require if val_byte is 1 */
if (val_bytes == 1) {
@@ -622,7 +650,7 @@
kfree(wval);
out:
- mutex_unlock(&map->lock);
+ map->unlock(map);
return ret;
}
EXPORT_SYMBOL_GPL(regmap_bulk_write);
@@ -696,11 +724,11 @@
{
int ret;
- mutex_lock(&map->lock);
+ map->lock(map);
ret = _regmap_read(map, reg, val);
- mutex_unlock(&map->lock);
+ map->unlock(map);
return ret;
}
@@ -725,7 +753,7 @@
unsigned int v;
int ret, i;
- mutex_lock(&map->lock);
+ map->lock(map);
if (regmap_volatile_range(map, reg, val_count) || map->cache_bypass ||
map->cache_type == REGCACHE_NONE) {
@@ -746,7 +774,7 @@
}
out:
- mutex_unlock(&map->lock);
+ map->unlock(map);
return ret;
}
@@ -799,7 +827,7 @@
int ret;
unsigned int tmp, orig;
- mutex_lock(&map->lock);
+ map->lock(map);
ret = _regmap_read(map, reg, &orig);
if (ret != 0)
@@ -816,7 +844,7 @@
}
out:
- mutex_unlock(&map->lock);
+ map->unlock(map);
return ret;
}
@@ -883,7 +911,7 @@
if (map->patch)
return -EBUSY;
- mutex_lock(&map->lock);
+ map->lock(map);
bypass = map->cache_bypass;
@@ -911,7 +939,7 @@
out:
map->cache_bypass = bypass;
- mutex_unlock(&map->lock);
+ map->unlock(map);
return ret;
}