ASoC: soc-cache: Introduce the cache_bypass option

This is primarily needed to avoid writing back to the cache
whenever we are syncing the cache with the hardware.  This gives a
performance benefit especially for large register maps.
Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

include/sound/soc.h

@@ -488,6 +488,7 @@ struct snd_soc_codec {
 	/* runtime */
 	struct snd_ac97 *ac97;  /* for ad-hoc ac97 devices */
 	unsigned int active;
+	unsigned int cache_bypass:1; /* Suppress access to the cache */
 	unsigned int cache_only:1;  /* Suppress writes to hardware */
 	unsigned int cache_sync:1; /* Cache needs to be synced to hardware */
 	unsigned int suspended:1; /* Codec is in suspend PM state */

sound/soc/soc-cache.c

@@ -25,7 +25,8 @@ static unsigned int snd_soc_4_12_read(struct snd_soc_codec *codec,
 	unsigned int val;
 
 	if (reg >= codec->driver->reg_cache_size ||
-		snd_soc_codec_volatile_register(codec, reg)) {
+		snd_soc_codec_volatile_register(codec, reg) ||
+		codec->cache_bypass) {
 			if (codec->cache_only)
 				return -1;
 
@@ -49,7 +50,8 @@ static int snd_soc_4_12_write(struct snd_soc_codec *codec, unsigned int reg,
 	data[1] = value & 0x00ff;
 
 	if (!snd_soc_codec_volatile_register(codec, reg) &&
-		reg < codec->driver->reg_cache_size) {
+		reg < codec->driver->reg_cache_size &&
+		!codec->cache_bypass) {
 		ret = snd_soc_cache_write(codec, reg, value);
 		if (ret < 0)
 			return -1;
@@ -106,7 +108,8 @@ static unsigned int snd_soc_7_9_read(struct snd_soc_codec *codec,
 	unsigned int val;
 
 	if (reg >= codec->driver->reg_cache_size ||
-		snd_soc_codec_volatile_register(codec, reg)) {
+		snd_soc_codec_volatile_register(codec, reg) ||
+		codec->cache_bypass) {
 			if (codec->cache_only)
 				return -1;
 
@@ -130,7 +133,8 @@ static int snd_soc_7_9_write(struct snd_soc_codec *codec, unsigned int reg,
 	data[1] = value & 0x00ff;
 
 	if (!snd_soc_codec_volatile_register(codec, reg) &&
-		reg < codec->driver->reg_cache_size) {
+		reg < codec->driver->reg_cache_size &&
+		!codec->cache_bypass) {
 		ret = snd_soc_cache_write(codec, reg, value);
 		if (ret < 0)
 			return -1;
@@ -191,7 +195,8 @@ static int snd_soc_8_8_write(struct snd_soc_codec *codec, unsigned int reg,
 	data[1] = value & 0xff;
 
 	if (!snd_soc_codec_volatile_register(codec, reg) &&
-		reg < codec->driver->reg_cache_size) {
+		reg < codec->driver->reg_cache_size &&
+		!codec->cache_bypass) {
 		ret = snd_soc_cache_write(codec, reg, value);
 		if (ret < 0)
 			return -1;
@@ -216,7 +221,8 @@ static unsigned int snd_soc_8_8_read(struct snd_soc_codec *codec,
 
 	reg &= 0xff;
 	if (reg >= codec->driver->reg_cache_size ||
-		snd_soc_codec_volatile_register(codec, reg)) {
+		snd_soc_codec_volatile_register(codec, reg) ||
+		codec->cache_bypass) {
 			if (codec->cache_only)
 				return -1;
 
@@ -271,7 +277,8 @@ static int snd_soc_8_16_write(struct snd_soc_codec *codec, unsigned int reg,
 	data[2] = value & 0xff;
 
 	if (!snd_soc_codec_volatile_register(codec, reg) &&
-		reg < codec->driver->reg_cache_size) {
+		reg < codec->driver->reg_cache_size &&
+		!codec->cache_bypass) {
 		ret = snd_soc_cache_write(codec, reg, value);
 		if (ret < 0)
 			return -1;
@@ -295,7 +302,8 @@ static unsigned int snd_soc_8_16_read(struct snd_soc_codec *codec,
 	unsigned int val;
 
 	if (reg >= codec->driver->reg_cache_size ||
-	    snd_soc_codec_volatile_register(codec, reg)) {
+	    snd_soc_codec_volatile_register(codec, reg) ||
+	    codec->cache_bypass) {
 		if (codec->cache_only)
 			return -1;
 
@@ -450,7 +458,8 @@ static unsigned int snd_soc_16_8_read(struct snd_soc_codec *codec,
 
 	reg &= 0xff;
 	if (reg >= codec->driver->reg_cache_size ||
-		snd_soc_codec_volatile_register(codec, reg)) {
+		snd_soc_codec_volatile_register(codec, reg) ||
+		codec->cache_bypass) {
 			if (codec->cache_only)
 				return -1;
 
@@ -476,7 +485,8 @@ static int snd_soc_16_8_write(struct snd_soc_codec *codec, unsigned int reg,
 
 	reg &= 0xff;
 	if (!snd_soc_codec_volatile_register(codec, reg) &&
-		reg < codec->driver->reg_cache_size) {
+		reg < codec->driver->reg_cache_size &&
+		!codec->cache_bypass) {
 		ret = snd_soc_cache_write(codec, reg, value);
 		if (ret < 0)
 			return -1;
@@ -568,7 +578,8 @@ static unsigned int snd_soc_16_16_read(struct snd_soc_codec *codec,
 	unsigned int val;
 
 	if (reg >= codec->driver->reg_cache_size ||
-	    snd_soc_codec_volatile_register(codec, reg)) {
+	    snd_soc_codec_volatile_register(codec, reg) ||
+	    codec->cache_bypass) {
 		if (codec->cache_only)
 			return -1;
 
@@ -595,7 +606,8 @@ static int snd_soc_16_16_write(struct snd_soc_codec *codec, unsigned int reg,
 	data[3] = value & 0xff;
 
 	if (!snd_soc_codec_volatile_register(codec, reg) &&
-		reg < codec->driver->reg_cache_size) {
+		reg < codec->driver->reg_cache_size &&
+		!codec->cache_bypass) {
 		ret = snd_soc_cache_write(codec, reg, value);
 		if (ret < 0)
 			return -1;