On Tue, 11 Aug 2009 01:07:10 +0200 Janusz Krzysztofik jkrzyszt@tis.icnet.pl wrote:
Enhance period index accuracy, particularly just before buffer rewind, by making use of DMA interrupt status flags in addition to simply counting up interrupts.
Corrections since v1:
- Fix buggy DMA interrupt handling in case of multiple status flags set in parallel.
- Enable OMAP_DMA_LAST_IRQ only for playback on OMAP1510.
This patch applies on top of patch 2 from this series: [RFC][PATCH 2/3] ASoC: OMAP: Make use of DMA channel self linking on OMAP1510
Created against linux-2.6.31-rc5.
Tested on Amstrad Delta.
Signed-off-by: Janusz Krzysztofik jkrzyszt@tis.icnet.pl
--- linux-2.6.31-rc5/sound/soc/omap/omap-pcm.c.orig 2009-08-10 22:41:25.000000000 +0200 +++ linux-2.6.31-rc5/sound/soc/omap/omap-pcm.c 2009-08-10 23:15:46.000000000 +0200 @@ -68,13 +68,27 @@ static void omap_pcm_dma_irq(int ch, u16 * 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 == 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; }
- }
- } else if (stat == OMAP_DMA_LAST_IRQ)
return;
Is this test needed? This interrupt is set only for playback on omap1510 so this looks null-op.
snd_pcm_period_elapsed(substream); } @@ -175,7 +189,12 @@ static int omap_pcm_prepare(struct snd_p 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);
Indent OMAP_DMA_LAST_IRQ with tab(s) and spaces to the same column than OMAP_DMA_FRAME_IRQ. Looks nicer then. Should the OMAP_DMA_BLOCK_IRQ to be set since it is handled in omap_pcm_dma_irq?