[alsa-devel] [Pull request] Support for wm9705 codec and two machines that use it.

Ian Molton ian at mnementh.co.uk
Fri Jan 16 14:39:45 CET 2009


Mark Brown wrote:

> On Fri, Jan 16, 2009 at 11:34:41AM +0000, Ian Molton wrote:
> 
>> It looks like register caching is a very common thing, would you be
>>  interested in a patch that consolidates the cache handling in
>> soc-core, rather than having multiple possibly broken
>> implementations around?
> 
> There's gotchas with variable register sizes and volatile bits (this
> was originally done more in the core but pushed out).  I've looked at
> it before and it looked like the best way to handle it was to do it
> along with a factoring out of common I/O routines.  Possibly best to
> leave it for now.

It looks to me like most chips could be handled with little difficulty -
a reg mask for some chips that have eg. 9 bit registers represented in a
u16, a reg_step to allow easy handling of different reg sizes, and an
array of register numbers for which the core should not cache values.

Easily 10 chips presently supported could use that scheme, whilst
leaving the function pointer based system available for the few really
weird chips.

>> Also, I could be wrong, but wm8980 caching looks completely broken 
>> (array is type u16 but there is no register shift applied, AFAICT)
> 
> There's normally a reason for the non-mainline drivers being that way
>  but in this case that's not it - the chip has 16 bit registers and
> the cache is being worked with as u16 * so natural array indexing
> should DTRT.

I cant quickly check that chip that now because I've rebased to the 
for-tiwai branch which it isnt in.

What does seem to be clear though is that there seems to be some
confusion as to what the 'reg' parameter to codec->read should be -
should it be a register _address_, or a register _number_.

If the former, then the caching in my wm9705 and a few other drivers is
broken. These treat reg as a register _address_ and shift it right by 1
to get the reg number and thus index into the reg cache.

If the latter, then other drivers may be making flawed assumptions, eg.
wm8753 which uses an array of u16 for the cache and treats 'reg' as a
register _number_ and uses it directly to index it, without a shift.

> Please post an incremental patch with your other changes.

Attached below for review.

I haven't added my SoB: as I havent tested it.

As you can see, the cache handling is done in several ways by different 
codecs, with inconsistent semantics and return codes (some BUG, some 
return 1 some -1 some -EIO. Some wont allow undefined reg access, some 
do, but only uncached.) This seems like ripe territory for bugs (albeit 
fairly harmless ones, but bugs nontheless).

ac97.c seems to have cookie-cutter-copied code to free a cache that it 
doesnt even have...

 From 93188b0b342bd849bc6aa62dca4ed33f71fcba0e Mon Sep 17 00:00:00 2001
From: Ian Molton <ian at mnementh.co.uk>
Date: Fri, 16 Jan 2009 13:31:52 +0000
Subject: [PATCH] ASoC: fixes to caching implementations

This patch takes fixes a number of bugs in the caching code used by
several ASoC codec drivers. Mostly off-by-one fixes.

---
  sound/soc/codecs/ac97.c    |    2 --
  sound/soc/codecs/ad1980.c  |    4 ++--
  sound/soc/codecs/twl4030.c |    3 +++
  sound/soc/codecs/wm8580.c  |    4 ++--
  sound/soc/codecs/wm8728.c  |    4 ++--
  sound/soc/codecs/wm8753.c  |    4 ++--
  sound/soc/codecs/wm8990.c  |    4 ++--
  sound/soc/codecs/wm9705.c  |    4 ++--
  sound/soc/codecs/wm9712.c  |    4 ++--
  sound/soc/codecs/wm9713.c  |    4 ++--
  10 files changed, 19 insertions(+), 18 deletions(-)

diff --git a/sound/soc/codecs/ac97.c b/sound/soc/codecs/ac97.c
index fb53e65..89d4127 100644
--- a/sound/soc/codecs/ac97.c
+++ b/sound/soc/codecs/ac97.c
@@ -123,7 +123,6 @@ bus_err:
  	snd_soc_free_pcms(socdev);

  err:
-	kfree(socdev->codec->reg_cache);
  	kfree(socdev->codec);
  	socdev->codec = NULL;
  	return ret;
@@ -138,7 +137,6 @@ static int ac97_soc_remove(struct platform_device *pdev)
  		return 0;

  	snd_soc_free_pcms(socdev);
-	kfree(socdev->codec->reg_cache);
  	kfree(socdev->codec);

  	return 0;
diff --git a/sound/soc/codecs/ad1980.c b/sound/soc/codecs/ad1980.c
index c3c5d0e..faf3587 100644
--- a/sound/soc/codecs/ad1980.c
+++ b/sound/soc/codecs/ad1980.c
@@ -109,7 +109,7 @@ static unsigned int ac97_read(struct snd_soc_codec 
*codec,
  	default:
  		reg = reg >> 1;

-		if (reg >= (ARRAY_SIZE(ad1980_reg)))
+		if (reg >= ARRAY_SIZE(ad1980_reg))
  			return -EINVAL;

  		return cache[reg];
@@ -123,7 +123,7 @@ static int ac97_write(struct snd_soc_codec *codec, 
unsigned int reg,

  	soc_ac97_ops.write(codec->ac97, reg, val);
  	reg = reg >> 1;
-	if (reg < (ARRAY_SIZE(ad1980_reg)))
+	if (reg < ARRAY_SIZE(ad1980_reg))
  		cache[reg] = val;

  	return 0;
diff --git a/sound/soc/codecs/twl4030.c b/sound/soc/codecs/twl4030.c
index ddc9f37..f530c1e 100644
--- a/sound/soc/codecs/twl4030.c
+++ b/sound/soc/codecs/twl4030.c
@@ -125,6 +125,9 @@ static inline unsigned int 
twl4030_read_reg_cache(struct snd_soc_codec *codec,
  {
  	u8 *cache = codec->reg_cache;

+	if (reg >= TWL4030_CACHEREGNUM)
+		return -EIO;
+
  	return cache[reg];
  }

diff --git a/sound/soc/codecs/wm8580.c b/sound/soc/codecs/wm8580.c
index 9b75a37..3faf0e7 100644
--- a/sound/soc/codecs/wm8580.c
+++ b/sound/soc/codecs/wm8580.c
@@ -200,7 +200,7 @@ static inline unsigned int 
wm8580_read_reg_cache(struct snd_soc_codec *codec,
  	unsigned int reg)
  {
  	u16 *cache = codec->reg_cache;
-	BUG_ON(reg > ARRAY_SIZE(wm8580_reg));
+	BUG_ON(reg >= ARRAY_SIZE(wm8580_reg));
  	return cache[reg];
  }

@@ -223,7 +223,7 @@ static int wm8580_write(struct snd_soc_codec *codec, 
unsigned int reg,
  {
  	u8 data[2];

-	BUG_ON(reg > ARRAY_SIZE(wm8580_reg));
+	BUG_ON(reg >= ARRAY_SIZE(wm8580_reg));

  	/* Registers are 9 bits wide */
  	value &= 0x1ff;
diff --git a/sound/soc/codecs/wm8728.c b/sound/soc/codecs/wm8728.c
index defa310..f90dc52 100644
--- a/sound/soc/codecs/wm8728.c
+++ b/sound/soc/codecs/wm8728.c
@@ -47,7 +47,7 @@ static inline unsigned int 
wm8728_read_reg_cache(struct snd_soc_codec *codec,
  	unsigned int reg)
  {
  	u16 *cache = codec->reg_cache;
-	BUG_ON(reg > ARRAY_SIZE(wm8728_reg_defaults));
+	BUG_ON(reg >= ARRAY_SIZE(wm8728_reg_defaults));
  	return cache[reg];
  }

@@ -55,7 +55,7 @@ static inline void wm8728_write_reg_cache(struct 
snd_soc_codec *codec,
  	u16 reg, unsigned int value)
  {
  	u16 *cache = codec->reg_cache;
-	BUG_ON(reg > ARRAY_SIZE(wm8728_reg_defaults));
+	BUG_ON(reg >= ARRAY_SIZE(wm8728_reg_defaults));
  	cache[reg] = value;
  }

diff --git a/sound/soc/codecs/wm8753.c b/sound/soc/codecs/wm8753.c
index 7283178..5a1c1fc 100644
--- a/sound/soc/codecs/wm8753.c
+++ b/sound/soc/codecs/wm8753.c
@@ -97,7 +97,7 @@ static inline unsigned int 
wm8753_read_reg_cache(struct snd_soc_codec *codec,
  	unsigned int reg)
  {
  	u16 *cache = codec->reg_cache;
-	if (reg < 1 || reg > (ARRAY_SIZE(wm8753_reg) + 1))
+	if (reg < 1 || reg >= (ARRAY_SIZE(wm8753_reg) + 1))
  		return -1;
  	return cache[reg - 1];
  }
@@ -109,7 +109,7 @@ static inline void wm8753_write_reg_cache(struct 
snd_soc_codec *codec,
  	unsigned int reg, unsigned int value)
  {
  	u16 *cache = codec->reg_cache;
-	if (reg < 1 || reg > 0x3f)
+	if (reg < 1 || reg >= (ARRAY_SIZE(wm8753_reg) + 1))
  		return;
  	cache[reg - 1] = value;
  }
diff --git a/sound/soc/codecs/wm8990.c b/sound/soc/codecs/wm8990.c
index 6b27786..f93c095 100644
--- a/sound/soc/codecs/wm8990.c
+++ b/sound/soc/codecs/wm8990.c
@@ -116,7 +116,7 @@ static inline unsigned int 
wm8990_read_reg_cache(struct snd_soc_codec *codec,
  	unsigned int reg)
  {
  	u16 *cache = codec->reg_cache;
-	BUG_ON(reg > (ARRAY_SIZE(wm8990_reg)) - 1);
+	BUG_ON(reg >= ARRAY_SIZE(wm8990_reg));
  	return cache[reg];
  }

@@ -129,7 +129,7 @@ static inline void wm8990_write_reg_cache(struct 
snd_soc_codec *codec,
  	u16 *cache = codec->reg_cache;

  	/* Reset register and reserved registers are uncached */
-	if (reg == 0 || reg > ARRAY_SIZE(wm8990_reg) - 1)
+	if (reg == 0 || reg >= ARRAY_SIZE(wm8990_reg))
  		return;

  	cache[reg] = value;
diff --git a/sound/soc/codecs/wm9705.c b/sound/soc/codecs/wm9705.c
index c6b7dc2..021b8ab 100644
--- a/sound/soc/codecs/wm9705.c
+++ b/sound/soc/codecs/wm9705.c
@@ -221,7 +221,7 @@ static unsigned int ac97_read(struct snd_soc_codec 
*codec, unsigned int reg)
  	default:
  		reg = reg >> 1;

-		if (reg > (ARRAY_SIZE(wm9705_reg)))
+		if (reg >= (ARRAY_SIZE(wm9705_reg)))
  			return -EIO;

  		return cache[reg];
@@ -235,7 +235,7 @@ static int ac97_write(struct snd_soc_codec *codec, 
unsigned int reg,

  	soc_ac97_ops.write(codec->ac97, reg, val);
  	reg = reg >> 1;
-	if (reg <= (ARRAY_SIZE(wm9705_reg)))
+	if (reg < (ARRAY_SIZE(wm9705_reg)))
  		cache[reg] = val;

  	return 0;
diff --git a/sound/soc/codecs/wm9712.c b/sound/soc/codecs/wm9712.c
index 1b0ace0..4dc90d6 100644
--- a/sound/soc/codecs/wm9712.c
+++ b/sound/soc/codecs/wm9712.c
@@ -452,7 +452,7 @@ static unsigned int ac97_read(struct snd_soc_codec 
*codec,
  	else {
  		reg = reg >> 1;

-		if (reg > (ARRAY_SIZE(wm9712_reg)))
+		if (reg >= (ARRAY_SIZE(wm9712_reg)))
  			return -EIO;

  		return cache[reg];
@@ -466,7 +466,7 @@ static int ac97_write(struct snd_soc_codec *codec, 
unsigned int reg,

  	soc_ac97_ops.write(codec->ac97, reg, val);
  	reg = reg >> 1;
-	if (reg <= (ARRAY_SIZE(wm9712_reg)))
+	if (reg < (ARRAY_SIZE(wm9712_reg)))
  		cache[reg] = val;

  	return 0;
diff --git a/sound/soc/codecs/wm9713.c b/sound/soc/codecs/wm9713.c
index a456226..d8ddca9 100644
--- a/sound/soc/codecs/wm9713.c
+++ b/sound/soc/codecs/wm9713.c
@@ -621,7 +621,7 @@ static unsigned int ac97_read(struct snd_soc_codec 
*codec,
  	else {
  		reg = reg >> 1;

-		if (reg > (ARRAY_SIZE(wm9713_reg)))
+		if (reg >= (ARRAY_SIZE(wm9713_reg)))
  			return -EIO;

  		return cache[reg];
@@ -635,7 +635,7 @@ static int ac97_write(struct snd_soc_codec *codec, 
unsigned int reg,
  	if (reg < 0x7c)
  		soc_ac97_ops.write(codec->ac97, reg, val);
  	reg = reg >> 1;
-	if (reg <= (ARRAY_SIZE(wm9713_reg)))
+	if (reg < (ARRAY_SIZE(wm9713_reg)))
  		cache[reg] = val;

  	return 0;
-- 
1.5.6.5



More information about the Alsa-devel mailing list