ASoC: dmaengine: add custom DMA config to snd_dmaengine_pcm_config
Add fields to struct snd_dmaengine_pcm_config to allow custom:
- DMA channel names.
This is useful when the default "tx" and "rx" channel names don't
apply, for example if a HW module supports multiple channels, each
having different DMA channel names. This is the case with the FIFOs
in Tegra's AHUB. This new facility can replace
SND_DMAENGINE_PCM_FLAG_CUSTOM_CHANNEL_NAME.
- DMA device
This allows requesting DMA channels for a device other than the device
which is registering the "PCM" driver. This is quite unusual, but is
currently useful on Tegra. In much HW, and in Tegra20, each DAI HW
module contains its own FIFOs which DMA writes to. However, in Tegra30,
the DMA FIFOs were split out AHUB HW module, which then routes the data
through a cross-bar, and into the DAI HW modules. However, the current
ASoC driver structure does not expose this detail, and acts as if the
FIFOs are still part of the DAI HW modules. Consequently, the "PCM"
driver is registered with the DAI HW module, yet the DMA channels must
be looked up in the AHUB HW module's device tree node. This new config
field allows that to happen. Eventually, the Tegra drivers will be
reworked to fully expose the AHUB, and this config field can be
removed.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>
diff --git a/include/sound/dmaengine_pcm.h b/include/sound/dmaengine_pcm.h
index 4ef986c..eb73a3a 100644
--- a/include/sound/dmaengine_pcm.h
+++ b/include/sound/dmaengine_pcm.h
@@ -114,6 +114,10 @@
* @compat_filter_fn: Will be used as the filter function when requesting a
* channel for platforms which do not use devicetree. The filter parameter
* will be the DAI's DMA data.
+ * @dma_dev: If set, request DMA channel on this device rather than the DAI
+ * device.
+ * @chan_names: If set, these custom DMA channel names will be requested at
+ * registration time.
* @pcm_hardware: snd_pcm_hardware struct to be used for the PCM.
* @prealloc_buffer_size: Size of the preallocated audio buffer.
*
@@ -130,6 +134,8 @@
struct snd_soc_pcm_runtime *rtd,
struct snd_pcm_substream *substream);
dma_filter_fn compat_filter_fn;
+ struct device *dma_dev;
+ const char *chan_names[SNDRV_PCM_STREAM_LAST + 1];
const struct snd_pcm_hardware *pcm_hardware;
unsigned int prealloc_buffer_size;
diff --git a/sound/soc/soc-generic-dmaengine-pcm.c b/sound/soc/soc-generic-dmaengine-pcm.c
index 1cb3494..5b70c55 100644
--- a/sound/soc/soc-generic-dmaengine-pcm.c
+++ b/sound/soc/soc-generic-dmaengine-pcm.c
@@ -288,7 +288,7 @@
};
static void dmaengine_pcm_request_chan_of(struct dmaengine_pcm *pcm,
- struct device *dev)
+ struct device *dev, const struct snd_dmaengine_pcm_config *config)
{
unsigned int i;
const char *name;
@@ -298,12 +298,26 @@
!dev->of_node)
return;
+ if (config->dma_dev) {
+ /*
+ * If this warning is seen, it probably means that your Linux
+ * device structure does not match your HW device structure.
+ * It would be best to refactor the Linux device structure to
+ * correctly match the HW structure.
+ */
+ dev_warn(dev, "DMA channels sourced from device %s",
+ dev_name(config->dma_dev));
+ dev = config->dma_dev;
+ }
+
for (i = SNDRV_PCM_STREAM_PLAYBACK; i <= SNDRV_PCM_STREAM_CAPTURE;
i++) {
if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX)
name = "rx-tx";
else
name = dmaengine_pcm_dma_channel_names[i];
+ if (config->chan_names[i])
+ name = config->chan_names[i];
pcm->chan[i] = dma_request_slave_channel(dev, name);
if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX)
break;
@@ -346,7 +360,7 @@
pcm->config = config;
pcm->flags = flags;
- dmaengine_pcm_request_chan_of(pcm, dev);
+ dmaengine_pcm_request_chan_of(pcm, dev, config);
if (flags & SND_DMAENGINE_PCM_FLAG_NO_RESIDUE)
ret = snd_soc_add_platform(dev, &pcm->platform,