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ASoC: generic-dmaengine-pcm: Add support for half-duplex 

Some platforms which are half-duplex share the same DMA channel between the
playback and capture stream. Add support for this to the generic dmaengine PCM
driver.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Tested-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
This commit is contained in:
Lars-Peter Clausen 2013-04-20 19:29:00 +02:00 committed by Mark Brown
parent 22f38f792e
commit d1e1406c6e
2 changed files with 35 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
include/sound/dmaengine_pcm.h
View File

@ -91,6 +91,11 @@ void snd_dmaengine_pcm_set_config_from_dai_data(
* bytes that are still left to transfer.
*/
#define SND_DMAENGINE_PCM_FLAG_NO_RESIDUE BIT(2)
/*
* The PCM is half duplex and the DMA channel is shared between capture and
* playback.
*/
#define SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX BIT(3)
/**
* struct snd_dmaengine_pcm_config - Configuration data for dmaengine based PCM

43
sound/soc/soc-generic-dmaengine-pcm.c
View File

@ -29,7 +29,7 @@ struct dmaengine_pcm {
struct dma_chan *chan[SNDRV_PCM_STREAM_CAPTURE + 1];
const struct snd_dmaengine_pcm_config *config;
struct snd_soc_platform platform;
bool compat;
unsigned int flags;
};
static struct dmaengine_pcm *soc_platform_to_pcm(struct snd_soc_platform *p)
@ -128,6 +128,9 @@ static struct dma_chan *dmaengine_pcm_compat_request_channel(
{
struct dmaengine_pcm *pcm = soc_platform_to_pcm(rtd->platform);
if ((pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX) && pcm->chan[0])
return pcm->chan[0];
if (pcm->config->compat_request_channel)
return pcm->config->compat_request_channel(rtd, substream);
@ -148,7 +151,7 @@ static int dmaengine_pcm_new(struct snd_soc_pcm_runtime *rtd)
if (!substream)
continue;
if (!pcm->chan[i] && pcm->compat) {
if (!pcm->chan[i] && (pcm->flags & SND_DMAENGINE_PCM_FLAG_COMPAT)) {
pcm->chan[i] = dmaengine_pcm_compat_request_channel(rtd,
substream);
}
@ -215,6 +218,25 @@ static const char * const dmaengine_pcm_dma_channel_names[] = {
[SNDRV_PCM_STREAM_CAPTURE] = "rx",
};
static void dmaengine_pcm_request_chan_of(struct dmaengine_pcm *pcm,
struct device_node *of_node)
{
unsigned int i;
if ((pcm->flags & SND_DMAENGINE_PCM_FLAG_NO_DT) || !of_node)
return;
if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX) {
pcm->chan[0] = of_dma_request_slave_channel(of_node, "tx_rx");
pcm->chan[1] = pcm->chan[0];
} else {
for (i = SNDRV_PCM_STREAM_PLAYBACK; i <= SNDRV_PCM_STREAM_CAPTURE; i++) {
pcm->chan[i] = of_dma_request_slave_channel(of_node,
dmaengine_pcm_dma_channel_names[i]);
}
}
}
/**
* snd_dmaengine_pcm_register - Register a dmaengine based PCM device
* @dev: The parent device for the PCM device
@ -225,23 +247,15 @@ int snd_dmaengine_pcm_register(struct device *dev,
const struct snd_dmaengine_pcm_config *config, unsigned int flags)
{
struct dmaengine_pcm *pcm;
unsigned int i;
pcm = kzalloc(sizeof(*pcm), GFP_KERNEL);
if (!pcm)
return -ENOMEM;
pcm->config = config;
pcm->flags = flags;
if (flags & SND_DMAENGINE_PCM_FLAG_COMPAT)
pcm->compat = true;
if (!(flags & SND_DMAENGINE_PCM_FLAG_NO_DT) && dev->of_node) {
for (i = SNDRV_PCM_STREAM_PLAYBACK; i <= SNDRV_PCM_STREAM_CAPTURE; i++) {
pcm->chan[i] = of_dma_request_slave_channel(dev->of_node,
dmaengine_pcm_dma_channel_names[i]);
}
}
dmaengine_pcm_request_chan_of(pcm, dev->of_node);
if (flags & SND_DMAENGINE_PCM_FLAG_NO_RESIDUE)
return snd_soc_add_platform(dev, &pcm->platform,
@ -272,8 +286,11 @@ void snd_dmaengine_pcm_unregister(struct device *dev)
pcm = soc_platform_to_pcm(platform);
for (i = SNDRV_PCM_STREAM_PLAYBACK; i <= SNDRV_PCM_STREAM_CAPTURE; i++) {
if (pcm->chan[i])
if (pcm->chan[i]) {
dma_release_channel(pcm->chan[i]);
if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX)
break;
}
}
snd_soc_remove_platform(platform);