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regmap: Lock the sync path, ensure we use the lockless _regmap_write()

PATCH Applied Dimitris Papastamos 2 participants 5 messages Sep 29, 2011 – Sep 30, 2011

Subsystems (2)
Driver core Register map abstraction
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Dimitris Papastamos

author
#0 lore raw

PATCH 1/4 regmap: Lock the sync path, ensure we use the lockless _regmap_write()

Signed-off-by Dimitris Papastamos <[email protected]>
---
 drivers/base/regmap/regcache-indexed.c |    4 ++--
 drivers/base/regmap/regcache-lzo.c     |    2 +-
 drivers/base/regmap/regcache-rbtree.c  |    2 +-
 drivers/base/regmap/regcache.c         |    4 +++-
 4 files changed, 7 insertions(+), 5 deletions(-)
drivers/base/regmap/regcache-indexed.c +2 -2
index 268497a..2e10bb1 100644
@@ -45,8 +45,8 @@ static int regcache_indexed_sync(struct regmap *map)
 	int ret;
 
 	for (i = 0; i < map->num_reg_defaults; i++) {
-		ret = regmap_write(map, map->reg_defaults[i].reg,
-				   map->reg_defaults[i].def);
+		ret = _regmap_write(map, map->reg_defaults[i].reg,
+				    map->reg_defaults[i].def);
 		if (ret < 0)
 			return ret;
 		dev_dbg(map->dev, "Synced register %#x, value %#x\n",
drivers/base/regmap/regcache-lzo.c +1 -1
index 9079cb5..ad6af92 100644
@@ -339,7 +339,7 @@ static int regcache_lzo_sync(struct regmap *map)
 		if (ret)
 			return ret;
 		map->cache_bypass = 1;
-		ret = regmap_write(map, i, val);
+		ret = _regmap_write(map, i, val);
 		map->cache_bypass = 0;
 		if (ret)
 			return ret;
drivers/base/regmap/regcache-rbtree.c +1 -1
index de32ced..40f23dd 100644
@@ -327,7 +327,7 @@ static int regcache_rbtree_sync(struct regmap *map)
 			if (val == def)
 				continue;
 			map->cache_bypass = 1;
-			ret = regmap_write(map, regtmp, val);
+			ret = _regmap_write(map, regtmp, val);
 			map->cache_bypass = 0;
 			if (ret)
 				return ret;
drivers/base/regmap/regcache.c +3 -1
index 4dfab41..8393c47 100644
@@ -230,6 +230,7 @@ int regcache_sync(struct regmap *map)
 
 	BUG_ON(!map->cache_ops);
 
+	mutex_lock(&map->lock);
 	dev_dbg(map->dev, "Syncing %s cache\n",
 		map->cache_ops->name);
 	name = map->cache_ops->name;

@@ -242,7 +243,7 @@ int regcache_sync(struct regmap *map)
 			if (ret < 0)
 				goto out;
 			map->cache_bypass = 1;
-			ret = regmap_write(map, i, val);
+			ret = _regmap_write(map, i, val);
 			map->cache_bypass = 0;
 			if (ret < 0)
 				goto out;

@@ -254,6 +255,7 @@ int regcache_sync(struct regmap *map)
 	}
 out:
 	trace_regcache_sync(map->dev, name, "stop");
+	mutex_unlock(&map->lock);
 
 	return ret;
 }
Signature · 1 line
1.7.6.4
author
#1 lore raw

PATCH 2/4 regmap: Save/restore the bypass state upon syncing

Signed-off-by Dimitris Papastamos <[email protected]>
---
 drivers/base/regmap/regcache.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)
drivers/base/regmap/regcache.c +5 -0
index 8393c47..f91bc7b 100644
@@ -227,10 +227,13 @@ int regcache_sync(struct regmap *map)
 	unsigned int val;
 	unsigned int i;
 	const char *name;
+	unsigned int bypass;
 
 	BUG_ON(!map->cache_ops);
 
 	mutex_lock(&map->lock);
+	/* Remember the initial bypass state */
+	bypass = map->cache_bypass;
 	dev_dbg(map->dev, "Syncing %s cache\n",
 		map->cache_ops->name);
 	name = map->cache_ops->name;

@@ -255,6 +258,8 @@ int regcache_sync(struct regmap *map)
 	}
 out:
 	trace_regcache_sync(map->dev, name, "stop");
+	/* Restore the bypass state */
+	map->cache_bypass = bypass;
 	mutex_unlock(&map->lock);
 
 	return ret;
Signature · 1 line
1.7.6.4
author
#2 lore raw

PATCH 3/4 regmap: Implement regcache_cache_bypass helper function

In reply to Dimitris Papastamos

Ensure we've got a function so users can enable/disable the cache bypass option.

Signed-off-by Dimitris Papastamos <[email protected]>
---
 drivers/base/regmap/regcache.c |   19 +++++++++++++++++++
 include/linux/regmap.h         |    1 +
 2 files changed, 20 insertions(+), 0 deletions(-)
drivers/base/regmap/regcache.c +19 -0
index f91bc7b..eaa2e20 100644
@@ -286,6 +286,25 @@ void regcache_cache_only(struct regmap *map, bool enable)
 }
 EXPORT_SYMBOL_GPL(regcache_cache_only);
 
+/**
+ * regcache_cache_bypass: Put a register map into cache bypass mode
+ *
+ * @map: map to configure
+ * @cache_only: flag if changes should not be written to the hardware
+ *
+ * When a register map is marked with the cache bypass option, writes
+ * to the register map API will only update the hardware and not the
+ * the cache directly.  This is useful when syncing the cache back to
+ * the hardware.
+ */
+void regcache_cache_bypass(struct regmap *map, bool enable)
+{
+	mutex_lock(&map->lock);
+	map->cache_bypass = enable;
+	mutex_unlock(&map->lock);
+}
+EXPORT_SYMBOL_GPL(regcache_cache_bypass);
+
 bool regcache_set_val(void *base, unsigned int idx,
 		      unsigned int val, unsigned int word_size)
 {
include/linux/regmap.h +1 -0
index 76ac255..3daac2d 100644
@@ -142,5 +142,6 @@ int regmap_update_bits(struct regmap *map, unsigned int reg,
 
 int regcache_sync(struct regmap *map);
 void regcache_cache_only(struct regmap *map, bool enable);
+void regcache_cache_bypass(struct regmap *map, bool enable);
 
 #endif
Signature · 1 line
1.7.6.4
author
#3 lore raw

PATCH 4/4 regmap: Ensure we scream if we enable cache bypass/only at the same time

In reply to Dimitris Papastamos
Signed-off-by Dimitris Papastamos <[email protected]>
---
 drivers/base/regmap/regcache.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
drivers/base/regmap/regcache.c +2 -0
index eaa2e20..1d07828 100644
@@ -281,6 +281,7 @@ EXPORT_SYMBOL_GPL(regcache_sync);
 void regcache_cache_only(struct regmap *map, bool enable)
 {
 	mutex_lock(&map->lock);
+	WARN_ON(map->cache_bypass && enable);
 	map->cache_only = enable;
 	mutex_unlock(&map->lock);
 }

@@ -300,6 +301,7 @@ EXPORT_SYMBOL_GPL(regcache_cache_only);
 void regcache_cache_bypass(struct regmap *map, bool enable)
 {
 	mutex_lock(&map->lock);
+	WARN_ON(map->cache_only && enable);
 	map->cache_bypass = enable;
 	mutex_unlock(&map->lock);
 }
Signature · 1 line
1.7.6.4