ASoC: dmaengine-pcm: Add a common DAI DMA data struct

This patch adds a common DMA data struct which can be used by DAI drivers to
communicate their DMA configuration requirements to the DMA pcm driver.  Having
a common data structure for this allows us to implement common functions on top
of them, which can be used by multiple platforms.

This patch also introduces a new function to initialize certain fields of a
dma_slave_config struct from the common DAI DMA data struct.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
Tested-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

include/sound/dmaengine_pcm.h

@@ -44,4 +44,28 @@ int snd_dmaengine_pcm_close(struct snd_pcm_substream *substream);
 
 struct dma_chan *snd_dmaengine_pcm_get_chan(struct snd_pcm_substream *substream);
 
+/**
+ * struct snd_dmaengine_dai_dma_data - DAI DMA configuration data
+ * @addr: Address of the DAI data source or destination register.
+ * @addr_width: Width of the DAI data source or destination register.
+ * @maxburst: Maximum number of words(note: words, as in units of the
+ * src_addr_width member, not bytes) that can be send to or received from the
+ * DAI in one burst.
+ * @slave_id: Slave requester id for the DMA channel.
+ * @filter_data: Custom DMA channel filter data, this will usually be used when
+ * requesting the DMA channel.
+ */
+struct snd_dmaengine_dai_dma_data {
+	dma_addr_t addr;
+	enum dma_slave_buswidth addr_width;
+	u32 maxburst;
+	unsigned int slave_id;
+	void *filter_data;
+};
+
+void snd_dmaengine_pcm_set_config_from_dai_data(
+	const struct snd_pcm_substream *substream,
+	const struct snd_dmaengine_dai_dma_data *dma_data,
+	struct dma_slave_config *config);
+
 #endif

sound/soc/soc-dmaengine-pcm.c

@@ -95,6 +95,43 @@ int snd_hwparams_to_dma_slave_config(const struct snd_pcm_substream *substream,
 }
 EXPORT_SYMBOL_GPL(snd_hwparams_to_dma_slave_config);
 
+/**
+ * snd_dmaengine_pcm_set_config_from_dai_data() - Initializes a dma slave config
+ *  using DAI DMA data.
+ * @substream: PCM substream
+ * @dma_data: DAI DMA data
+ * @slave_config: DMA slave configuration
+ *
+ * Initializes the {dst,src}_addr, {dst,src}_maxburst, {dst,src}_addr_width and
+ * slave_id fields of the DMA slave config from the same fields of the DAI DMA
+ * data struct. The src and dst fields will be initialized depending on the
+ * direction of the substream. If the substream is a playback stream the dst
+ * fields will be initialized, if it is a capture stream the src fields will be
+ * initialized. The {dst,src}_addr_width field will only be initialized if the
+ * addr_width field of the DAI DMA data struct is not equal to
+ * DMA_SLAVE_BUSWIDTH_UNDEFINED.
+ */
+void snd_dmaengine_pcm_set_config_from_dai_data(
+	const struct snd_pcm_substream *substream,
+	const struct snd_dmaengine_dai_dma_data *dma_data,
+	struct dma_slave_config *slave_config)
+{
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+		slave_config->dst_addr = dma_data->addr;
+		slave_config->dst_maxburst = dma_data->maxburst;
+		if (dma_data->addr_width != DMA_SLAVE_BUSWIDTH_UNDEFINED)
+			slave_config->dst_addr_width = dma_data->addr_width;
+	} else {
+		slave_config->src_addr = dma_data->addr;
+		slave_config->src_maxburst = dma_data->maxburst;
+		if (dma_data->addr_width != DMA_SLAVE_BUSWIDTH_UNDEFINED)
+			slave_config->src_addr_width = dma_data->addr_width;
+	}
+
+	slave_config->slave_id = dma_data->slave_id;
+}
+EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_set_config_from_dai_data);
+
 static void dmaengine_pcm_dma_complete(void *arg)
 {
 	struct snd_pcm_substream *substream = arg;