With generic DMA device tree binding and helper function dma_request_slave_channel() in place, dmaengine_pcm should support that in requesting DMA channel for users that support generic DMA device tree binding.
Add a new API snd_dmaengine_generic_pcm_open() as the variant of snd_dmaengine_pcm_open(). It takes DMA client struct device pointer and slave channel name as arguments and calls generic DMA helper dma_request_slave_channel() to request DMA channel from dmaengine.
Signed-off-by: Shawn Guo shawn.guo@linaro.org Cc: Mark Brown broonie@opensource.wolfsonmicro.com Cc: alsa-devel@alsa-project.org --- Mark,
Please maintain a topic branch for the patch if it looks good to you. It should be useful for any dmaengine_pcm user that is moving to generic DMA device tree binding.
Thanks, Shawn
include/sound/dmaengine_pcm.h | 2 ++ sound/soc/soc-dmaengine-pcm.c | 39 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 41 insertions(+)
diff --git a/include/sound/dmaengine_pcm.h b/include/sound/dmaengine_pcm.h index b877334..452df15 100644 --- a/include/sound/dmaengine_pcm.h +++ b/include/sound/dmaengine_pcm.h @@ -43,6 +43,8 @@ snd_pcm_uframes_t snd_dmaengine_pcm_pointer_no_residue(struct snd_pcm_substream
int snd_dmaengine_pcm_open(struct snd_pcm_substream *substream, dma_filter_fn filter_fn, void *filter_data); +int snd_dmaengine_generic_pcm_open(struct snd_pcm_substream *substream, + struct device *dev, const char *name); int snd_dmaengine_pcm_close(struct snd_pcm_substream *substream);
struct dma_chan *snd_dmaengine_pcm_get_chan(struct snd_pcm_substream *substream); diff --git a/sound/soc/soc-dmaengine-pcm.c b/sound/soc/soc-dmaengine-pcm.c index 111b7d92..970eb2b 100644 --- a/sound/soc/soc-dmaengine-pcm.c +++ b/sound/soc/soc-dmaengine-pcm.c @@ -304,6 +304,45 @@ int snd_dmaengine_pcm_open(struct snd_pcm_substream *substream, EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_open);
/** + * snd_dmaengine_generic_pcm_open - Open a dmaengine based PCM substream + * @substream: PCM substream + * @dev: pointer to DMA client device structure + * @name: DMA slave channel name + * + * Returns 0 on success, a negative error code otherwise. + * + * This function is a variant of snd_dmaengine_pcm_open(). It takes different + * parameters and calls generic DMA helper dma_request_slave_channel() to + * request a DMA channel from dmaengine. + */ +int snd_dmaengine_generic_pcm_open(struct snd_pcm_substream *substream, + struct device *dev, const char *name) +{ + struct dmaengine_pcm_runtime_data *prtd; + int ret; + + ret = snd_pcm_hw_constraint_integer(substream->runtime, + SNDRV_PCM_HW_PARAM_PERIODS); + if (ret < 0) + return ret; + + prtd = kzalloc(sizeof(*prtd), GFP_KERNEL); + if (!prtd) + return -ENOMEM; + + prtd->dma_chan = dma_request_slave_channel(dev, name); + if (!prtd->dma_chan) { + kfree(prtd); + return -ENXIO; + } + + substream->runtime->private_data = prtd; + + return 0; +} +EXPORT_SYMBOL_GPL(snd_dmaengine_generic_pcm_open); + +/** * snd_dmaengine_pcm_close - Close a dmaengine based PCM substream * @substream: PCM substream */