ASoC: dmaengine_pcm: Add support for compat platforms

Add support for platforms which don't use devicetree yet or have to optionally
support a non-devicetree way to request the DMA channel. The patch adds the
compat_request_channel and compat_filter_fn callbacks to the
snd_dmaengine_pcm_config struct. If the compat_request_channel is implemented it
will be used to request the DMA channel. If not dma_request_channel with
compat_filter_fn as the filter function will be used to request the channel.

The patch also exports the snd_dmaengine_pcm_request_chan() function, since
compat platforms will want to use it to request their DMA channel.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Tested-by: Stephen Warren <swarren@nvidia.com>
Tested-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 29 insertions, 0 deletions

diff --git a/include/sound/dmaengine_pcm.h b/include/sound/dmaengine_pcm.h
index e0bf24e..1a7897a 100644
--- a/include/sound/dmaengine_pcm.h
+++ b/include/sound/dmaengine_pcm.h
@@ -16,6 +16,7 @@
 #define __SOUND_DMAENGINE_PCM_H__
 
 #include <sound/pcm.h>
+#include <sound/soc.h>
 #include <linux/dmaengine.h>
 
 /**
@@ -46,6 +47,8 @@ int snd_dmaengine_pcm_open_request_chan(struct snd_pcm_substream *substream,
 	dma_filter_fn filter_fn, void *filter_data);
 int snd_dmaengine_pcm_close_release_chan(struct snd_pcm_substream *substream);
 
+struct dma_chan *snd_dmaengine_pcm_request_channel(dma_filter_fn filter_fn,
+	void *filter_data);
 struct dma_chan *snd_dmaengine_pcm_get_chan(struct snd_pcm_substream *substream);
 
 /**
@@ -72,17 +75,43 @@ void snd_dmaengine_pcm_set_config_from_dai_data(
 	const struct snd_dmaengine_dai_dma_data *dma_data,
 	struct dma_slave_config *config);
 
+
+/*
+ * Try to request the DMA channel using compat_request_channel or
+ * compat_filter_fn if it couldn't be requested through devicetree.
+ */
+#define SND_DMAENGINE_PCM_FLAG_COMPAT BIT(0)
+/*
+ * Don't try to request the DMA channels through devicetree. This flag only
+ * makes sense if SND_DMAENGINE_PCM_FLAG_COMPAT is set as well.
+ */
+#define SND_DMAENGINE_PCM_FLAG_NO_DT BIT(1)
+
 /**
  * struct snd_dmaengine_pcm_config - Configuration data for dmaengine based PCM
  * @prepare_slave_config: Callback used to fill in the DMA slave_config for a
  *   PCM substream. Will be called from the PCM drivers hwparams callback.
+ * @compat_request_channel: Callback to request a DMA channel for platforms
+ *   which do not use devicetree.
+ * @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.
  * @pcm_hardware: snd_pcm_hardware struct to be used for the PCM.
  * @prealloc_buffer_size: Size of the preallocated audio buffer.
+ *
+ * Note: If both compat_request_channel and compat_filter_fn are set
+ * compat_request_channel will be used to request the channel and
+ * compat_filter_fn will be ignored. Otherwise the channel will be requested
+ * using dma_request_channel with compat_filter_fn as the filter function.
  */
 struct snd_dmaengine_pcm_config {
 	int (*prepare_slave_config)(struct snd_pcm_substream *substream,
 			struct snd_pcm_hw_params *params,
 			struct dma_slave_config *slave_config);
+	struct dma_chan *(*compat_request_channel)(
+			struct snd_soc_pcm_runtime *rtd,
+			struct snd_pcm_substream *substream);
+	dma_filter_fn compat_filter_fn;
 
 	const struct snd_pcm_hardware *pcm_hardware;
 	unsigned int prealloc_buffer_size;