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SubjectRe: [RFC PATCH 01/13] misc: atmel_ssc: add device tree DMA support
2013/7/4 Bo Shen <voice.shen@atmel.com>:
> Hi Richard,
>
>
> On 7/3/2013 23:51, Richard Genoud wrote:
>>>
>>> >but there's a violent hang (kernel stops, no trace) when I try the
>>> > record :
>>> >arecord -v -V stereo -Dplug:default -f cd -t wav -c 2 /tmp/toto.wav
>>> >last thing I see is :
>>> >dma dma0chan3: atc_control (3)
>
>
> I don't meet this issue. Playback and recording works well on my side on
> at91sam9g35ek board.
>
>
>>> >I'll try to trace that.
>>
>> I think it's DMA related.
>> the last thing done by the kernel is:
>> i2c i2c-0: i2c_outb: 0x34 A
>> i2c i2c-0: i2c_outb: 0x0c A
>> i2c i2c-0: i2c_outb: 0x5a A
>> meaning: enable power on, LINE IN, ADC, OSC, on the WM8731
>> so, after that, data is comming from the codec to the SSC and then is
>> handled by the DMA.
>> there must be something nasty on the DMA bus to hang everything like
>> that...
>
>
> Will you try i2c without DMA support to test this issue?

Ok, I nailed it !

To be sure we are on the same base, here is what I have done:
onto next-20130704:
- your 5 patches:
ASoC: atmel_ssc_dai: move set dma data to startup callback
ASoC: atmel_ssc_dai: add error mask define
ASoC: atmel-pcm-dma: move prepare for dma to dai prepare
ARM: atmel-ssc: change phybase type to dma_addr_t
ASoC: atmel-pcm: use generic dmaengine framework
- my patches 4-8:
ARM: at91: DTS: sam9x5: add SSC DMA parameters
ARM: AT91: DTS: sam9x5ek: add WM8731 codec
ARM: AT91: DTS: sam9x5ek: add sound configuration
ARM: AT91: DTS: sam9x5ek: enable SSC
sound: sam9x5_wm8731: machine driver for at91sam9x5 wm8731 boards

To be sure that dma-I2c doesn't disturb something, I use i2c gpio bitbang:
diff --git a/arch/arm/boot/dts/at91sam9x5ek.dtsi
b/arch/arm/boot/dts/at91sam9x5ek.dtsi
index 6684d4b..53a991e 100644
--- a/arch/arm/boot/dts/at91sam9x5ek.dtsi
+++ b/arch/arm/boot/dts/at91sam9x5ek.dtsi
@@ -57,15 +57,6 @@
status = "okay";
};

- i2c0: i2c@f8010000 {
- status = "okay";
-
- wm8731: wm8731@1a {
- compatible = "wm8731";
- reg = <0x1a>;
- };
- };
-
pinctrl@fffff400 {
mmc0 {
pinctrl_board_mmc0: mmc0-board {
@@ -114,6 +105,15 @@
};
};

+ i2c@0 {
+ status = "okay";
+
+ wm8731: wm8731@1a {
+ compatible = "wm8731";
+ reg = <0x1a>;
+ };
+ };
+
sound {
compatible = "atmel,sam9x5-audio-wm8731";

with that configuration, it hangs when I do a:
arecord -v -V stereo -Dplug:default -f cd -t wav -c 2 /tmp/toto.wav
Now, if I remove the overrun error on ssc in rx_mask:
diff --git a/sound/soc/atmel/atmel_ssc_dai.c b/sound/soc/atmel/atmel_ssc_dai.c
index 0ecf356..c04e825 100644
--- a/sound/soc/atmel/atmel_ssc_dai.c
+++ b/sound/soc/atmel/atmel_ssc_dai.c
@@ -83,7 +83,6 @@ static struct atmel_ssc_mask ssc_rx_mask = {
.ssc_disable = SSC_BIT(CR_RXDIS),
.ssc_endx = SSC_BIT(SR_ENDRX),
.ssc_endbuf = SSC_BIT(SR_RXBUFF),
- .ssc_error = SSC_BIT(SR_OVRUN),
.pdc_enable = ATMEL_PDC_RXTEN,
.pdc_disable = ATMEL_PDC_RXTDIS,
};
It doesn't hang any more doing a simple record.
BUT it still hangs if we do record and play at the same time.

Removing the overrun on tx_mask prevent the hang:
diff --git a/sound/soc/atmel/atmel_ssc_dai.c b/sound/soc/atmel/atmel_ssc_dai.c
index 0ecf356..41e15c2 100644
--- a/sound/soc/atmel/atmel_ssc_dai.c
+++ b/sound/soc/atmel/atmel_ssc_dai.c
@@ -73,7 +73,6 @@ static struct atmel_ssc_mask ssc_tx_mask = {
.ssc_disable = SSC_BIT(CR_TXDIS),
.ssc_endx = SSC_BIT(SR_ENDTX),
.ssc_endbuf = SSC_BIT(SR_TXBUFE),
- .ssc_error = SSC_BIT(SR_OVRUN),
.pdc_enable = ATMEL_PDC_TXTEN,
.pdc_disable = ATMEL_PDC_TXTDIS,
};
i.e. when I revert "ASoC: atmel_ssc_dai: add error mask define", I
don't see any hang.

Could you test and confirm that behaviour please ?

I attached a the (simple) .config I used for the tests.

PS: I hope the patches won't be mangled by gmail...

Best regards,
Richard.
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