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ASoC: OMAP: Enhance OMAP1510 DMA progress software counter

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Enhance period_index accuracy, particularly just before buffer rewind, by
making use of DMA interrupt status flags in addition to simply counting up
interrupts.

Created against linux-2.6.31-rc5.

Tested on Amstrad Delta.

Signed-off-by: Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>
Acked-by: Jarkko Nikula <jhnikula@gmail.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
This commit is contained in:
Janusz Krzysztofik 2009-08-11 21:44:29 +02:00 committed by Mark Brown
parent 64844a6ac8
commit 471e3dec3a
1 changed files with 20 additions and 2 deletions
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22
sound/soc/omap/omap-pcm.c
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@ -68,8 +68,21 @@ static void omap_pcm_dma_irq(int ch, u16 stat, void *data)
* that can be used by omap_pcm_pointer() instead.
*/
spin_lock_irqsave(&prtd->lock, flags);
if ((stat == OMAP_DMA_LAST_IRQ) &&
(prtd->period_index == runtime->periods - 1)) {
/* we are in sync, do nothing */
spin_unlock_irqrestore(&prtd->lock, flags);
return;
}
if (prtd->period_index >= 0) {
if (++prtd->period_index == runtime->periods) {
if (stat & OMAP_DMA_BLOCK_IRQ) {
/* end of buffer reached, loop back */
prtd->period_index = 0;
} else if (stat & OMAP_DMA_LAST_IRQ) {
/* update the counter for the last period */
prtd->period_index = runtime->periods - 1;
} else if (++prtd->period_index >= runtime->periods) {
/* end of buffer missed? loop back */
prtd->period_index = 0;
}
}
@ -175,7 +188,12 @@ static int omap_pcm_prepare(struct snd_pcm_substream *substream)
dma_params.frame_count = runtime->periods;
omap_set_dma_params(prtd->dma_ch, &dma_params);
omap_enable_dma_irq(prtd->dma_ch, OMAP_DMA_FRAME_IRQ);
if ((cpu_is_omap1510()) &&
(substream->stream == SNDRV_PCM_STREAM_PLAYBACK))
omap_enable_dma_irq(prtd->dma_ch, OMAP_DMA_FRAME_IRQ |
OMAP_DMA_LAST_IRQ | OMAP_DMA_BLOCK_IRQ);
else
omap_enable_dma_irq(prtd->dma_ch, OMAP_DMA_FRAME_IRQ);
return 0;
}