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ASoC: S3C platform: Fix s3c2410_dma_started() called at improper time

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s3c24xx dma has the auto reload feature, when the the trnasfer is done,
CURR_TC(DSTAT[19:0], current value of transfer count) reaches 0, and DMA
ACK becomes 1, and then, TC(DCON[19:0]) will be loaded into CURR_TC. So
the transmission is repeated.

IRQ is issued while auto reload occurs. We change the DISRC and
DCON[19:0] in the ISR, but at this time, the auto reload has been
performed already. The first block is being re-transmitted by the DMA.

So we need rewrite the DISRC and DCON[19:0] for the next block
immediatly after the this block has been started to be transported.

The function s3c2410_dma_started() is for this perpose, which is called
in the form of "s3c2410_dma_ctrl(prtd->params->channel,
S3C2410_DMAOP_STARTED);" in s3c24xx_pcm_trigger().

But it is not correct. DMA transmission won't start until DMA REQ signal
arrived, it is the time s3c24xx_snd_txctrl(1) or s3c24xx_snd_rxctrl(1)
is called in s3c24xx_i2s_trigger().

In the current framework, s3c24xx_pcm_trigger() is always called before
s3c24xx_pcm_trigger(). So the s3c2410_dma_started() should be called in
s3c24xx_pcm_trigger() after s3c24xx_snd_txctrl(1) or
s3c24xx_snd_rxctrl(1) is called in this function.

However, s3c2410_dma_started() is dma related, to call this function we
should provide the channel number, which is given by
substream->runtime->private_data->params->channel. The private_data
points to a struct s3c24xx_runtime_data object, which is define in
s3c24xx_pcm.c, so s3c2410_dma_started() can't be called in s3c24xx_i2s.c

Fix this by moving the call to signal the DMA started to the DAI
drivers.

Signed-off-by: Shine Liu <liuxian@redflag-linux.com>
Signed-off-by: Shine Liu <shinel@foxmail.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
This commit is contained in:
Shine Liu
2009-08-25 20:05:50 +08:00
committed by Mark Brown
parent d09a2afc93
commit faf907c7ba
4 changed files with 25 additions and 1 deletions
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10
sound/soc/s3c24xx/s3c-i2s-v2.c
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@@ -387,6 +387,8 @@ static int s3c2412_i2s_trigger(struct snd_pcm_substream *substream, int cmd,
int capture = (substream->stream == SNDRV_PCM_STREAM_CAPTURE);
unsigned long irqs;
int ret = 0;
int channel = ((struct s3c24xx_pcm_dma_params *)
rtd->dai->cpu_dai->dma_data)->channel;
pr_debug("Entered %s\n", __func__);
@@ -416,6 +418,14 @@ static int s3c2412_i2s_trigger(struct snd_pcm_substream *substream, int cmd,
s3c2412_snd_txctrl(i2s, 1);
local_irq_restore(irqs);
/*
* Load the next buffer to DMA to meet the reqirement
* of the auto reload mechanism of S3C24XX.
* This call won't bother S3C64XX.
*/
s3c2410_dma_ctrl(channel, S3C2410_DMAOP_STARTED);
break;
case SNDRV_PCM_TRIGGER_STOP: