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[ARM] 4140/1: AACI stability add ac97 timeout and retries

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Add timeouts to hardware read/write/probe functions in order
to avoid lockups on buggy/broken hardware.

Signed-off-by: Kevin Hilman <khilman@mvista.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Kevin Hilman 2007-02-07 05:46:47 +01:00 committed by Russell King
parent 41762b8ca9
commit 14d178a143
1 changed files with 39 additions and 11 deletions
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50
sound/arm/aaci.c
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@ -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;
}