Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=14d178a143568f3651a40af6defadd44fb0b6b81
Commit: 14d178a143568f3651a40af6defadd44fb0b6b81
Parent: 41762b8ca9e16c7443d8348ec53daddbe940cdcc
Author: Kevin Hilman <[EMAIL PROTECTED]>
AuthorDate: Wed Feb 7 05:46:47 2007 +0100
Committer: Russell King <[EMAIL PROTECTED]>
CommitDate: Sun Feb 18 10:59:50 2007 +0000
[ARM] 4140/1: AACI stability add ac97 timeout and retries
Add timeouts to hardware read/write/probe functions in order
to avoid lockups on buggy/broken hardware.
Signed-off-by: Kevin Hilman <[EMAIL PROTECTED]>
Signed-off-by: Russell King <[EMAIL PROTECTED]>
---
sound/arm/aaci.c | 50 +++++++++++++++++++++++++++++++++++++++-----------
1 files changed, 39 insertions(+), 11 deletions(-)
diff --git a/sound/arm/aaci.c b/sound/arm/aaci.c
index a032aee..5190d7a 100644
--- a/sound/arm/aaci.c
+++ b/sound/arm/aaci.c
@@ -65,10 +65,12 @@ static void aaci_ac97_select_codec(struct aaci *aaci,
struct snd_ac97 *ac97)
* SI1TxEn, SI2TxEn and SI12TxEn bits are set in the AACI_MAINCR
* register.
*/
-static void aaci_ac97_write(struct snd_ac97 *ac97, unsigned short reg,
unsigned short val)
+static void aaci_ac97_write(struct snd_ac97 *ac97, unsigned short reg,
+ unsigned short val)
{
struct aaci *aaci = ac97->private_data;
u32 v;
+ int timeout = 5000;
if (ac97->num >= 4)
return;
@@ -89,7 +91,11 @@ static void aaci_ac97_write(struct snd_ac97 *ac97, unsigned
short reg, unsigned
*/
do {
v = readl(aaci->base + AACI_SLFR);
- } while (v & (SLFR_1TXB|SLFR_2TXB));
+ } while ((v & (SLFR_1TXB|SLFR_2TXB)) && timeout--);
+
+ if (!timeout)
+ dev_err(&aaci->dev->dev,
+ "timeout waiting for write to complete\n");
mutex_unlock(&aaci->ac97_sem);
}
@@ -101,6 +107,8 @@ static unsigned short aaci_ac97_read(struct snd_ac97 *ac97,
unsigned short reg)
{
struct aaci *aaci = ac97->private_data;
u32 v;
+ int timeout = 5000;
+ int retries = 10;
if (ac97->num >= 4)
return ~0;
@@ -119,7 +127,13 @@ static unsigned short aaci_ac97_read(struct snd_ac97
*ac97, unsigned short reg)
*/
do {
v = readl(aaci->base + AACI_SLFR);
- } while (v & SLFR_1TXB);
+ } while ((v & SLFR_1TXB) && timeout--);
+
+ if (!timeout) {
+ dev_err(&aaci->dev->dev, "timeout on slot 1 TX busy\n");
+ v = ~0;
+ goto out;
+ }
/*
* Give the AC'97 codec more than enough time
@@ -130,21 +144,35 @@ static unsigned short aaci_ac97_read(struct snd_ac97
*ac97, unsigned short reg)
/*
* Wait for slot 2 to indicate data.
*/
+ timeout = 5000;
do {
cond_resched();
v = readl(aaci->base + AACI_SLFR) & (SLFR_1RXV|SLFR_2RXV);
- } while (v != (SLFR_1RXV|SLFR_2RXV));
+ } while ((v != (SLFR_1RXV|SLFR_2RXV)) && timeout--);
- v = readl(aaci->base + AACI_SL1RX) >> 12;
- if (v == reg) {
- v = readl(aaci->base + AACI_SL2RX) >> 4;
- } else {
- dev_err(&aaci->dev->dev,
- "wrong ac97 register read back (%x != %x)\n",
- v, reg);
+ if (!timeout) {
+ dev_err(&aaci->dev->dev, "timeout on RX valid\n");
v = ~0;
+ goto out;
}
+ do {
+ v = readl(aaci->base + AACI_SL1RX) >> 12;
+ if (v == reg) {
+ v = readl(aaci->base + AACI_SL2RX) >> 4;
+ break;
+ } else if (--retries) {
+ dev_warn(&aaci->dev->dev,
+ "ac97 read back fail. retry\n");
+ continue;
+ } else {
+ dev_warn(&aaci->dev->dev,
+ "wrong ac97 register read back (%x != %x)\n",
+ v, reg);
+ v = ~0;
+ }
+ } while (retries);
+ out:
mutex_unlock(&aaci->ac97_sem);
return v;
}
-
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