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Commit 471e3dec authored by Janusz Krzysztofik's avatar Janusz Krzysztofik Committed by Mark Brown
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ASoC: OMAP: Enhance OMAP1510 DMA progress software counter 



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: default avatarJanusz Krzysztofik <jkrzyszt@tis.icnet.pl>
Acked-by: default avatarJarkko Nikula <jhnikula@gmail.com>
Signed-off-by: default avatarMark Brown <broonie@opensource.wolfsonmicro.com>
parent 64844a6a

sound/soc/omap/omap-pcm.c

+20 −2
Original line number Diff line number Diff line
@@ -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;

			}

		}
@@ -175,6 +188,11 @@ 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);



	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;