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authorJanusz Krzysztofik <jkrzyszt@tis.icnet.pl>2009-08-10 10:50:04 +0200
committerMark Brown <broonie@opensource.wolfsonmicro.com>2009-08-17 10:59:59 +0100
commit64844a6ac8ddd586cb832fea7cf2e93e5e7e03f4 (patch)
tree478fccc70ac7a17861e449438683c22130335e0e /sound
parent1e97f50b7023cda00cb720e53b9e59c250cb4ed7 (diff)
downloadlinux-linaro-precise-64844a6ac8ddd586cb832fea7cf2e93e5e7e03f4.tar.gz
ASoC: OMAP: Make use of DMA channel self linking on OMAP1510
Use newly implemented DMA channel self linking on OMAP1510 like on other OMAP models. Remove unnecessary DMA transfer restart from interrupt handler routine. The interrupt routine used to maintain a period index, originally needed for counting up periods up to a full buffer in order to restart the DMA transfer. For some time, this counter is also used as a replacement for hardware DMA progress counter that has been found unusable on OMAP1510 in case of playback. Thus, the period index calculation cannot be omitted completely. However, the accuracy of this counter can still suffer from missing DMA interrupts. In order to work correctly, it requires patch 1 from this series also applied: [RFC][PATCH 1/3] ARM: OMAP: DMA: Add support for 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> Acked-by: Jarkko Nikula <jhnikula@gmail.com> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Diffstat (limited to 'sound')
-rw-r--r--sound/soc/omap/omap-pcm.c15
1 files changed, 8 insertions, 7 deletions
diff --git a/sound/soc/omap/omap-pcm.c b/sound/soc/omap/omap-pcm.c
index c3c931d4537..3e3a9d478c0 100644
--- a/sound/soc/omap/omap-pcm.c
+++ b/sound/soc/omap/omap-pcm.c
@@ -59,16 +59,18 @@ static void omap_pcm_dma_irq(int ch, u16 stat, void *data)
struct omap_runtime_data *prtd = runtime->private_data;
unsigned long flags;
- if (cpu_is_omap1510()) {
+ if ((cpu_is_omap1510()) &&
+ (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)) {
/*
- * OMAP1510 doesn't support DMA chaining so have to restart
- * the transfer after all periods are transferred
+ * OMAP1510 doesn't fully support DMA progress counter
+ * and there is no software emulation implemented yet,
+ * so have to maintain our own playback progress counter
+ * that can be used by omap_pcm_pointer() instead.
*/
spin_lock_irqsave(&prtd->lock, flags);
if (prtd->period_index >= 0) {
if (++prtd->period_index == runtime->periods) {
prtd->period_index = 0;
- omap_start_dma(prtd->dma_ch);
}
}
spin_unlock_irqrestore(&prtd->lock, flags);
@@ -100,7 +102,7 @@ static int omap_pcm_hw_params(struct snd_pcm_substream *substream,
prtd->dma_data = dma_data;
err = omap_request_dma(dma_data->dma_req, dma_data->name,
omap_pcm_dma_irq, substream, &prtd->dma_ch);
- if (!err && !cpu_is_omap1510()) {
+ if (!err) {
/*
* Link channel with itself so DMA doesn't need any
* reprogramming while looping the buffer
@@ -119,8 +121,7 @@ static int omap_pcm_hw_free(struct snd_pcm_substream *substream)
if (prtd->dma_data == NULL)
return 0;
- if (!cpu_is_omap1510())
- omap_dma_unlink_lch(prtd->dma_ch, prtd->dma_ch);
+ omap_dma_unlink_lch(prtd->dma_ch, prtd->dma_ch);
omap_free_dma(prtd->dma_ch);
prtd->dma_data = NULL;