On Tue, Oct 08, 2013 at 03:07:59PM +0200, Lars-Peter Clausen wrote:
Currently each platform making use the the generic dmaengine PCM driver still needs to provide a custom snd_pcm_hardware struct which specifies the capabilities of the DMA controller, e.g. the maximum period size that can be supported. This patch adds code which uses the newly introduced dma_get_slave_caps() API to query this information from the dmaengine driver. The new code path will only be taken if the 'pcm_hardware' field of the snd_dmaengine_pcm_config struct is NULL.
The patch also introduces a new 'fifo_size' field to the snd_dmaengine_dai_dma_data struct which is used to initialize the snd_pcm_hardware 'fifo_size' field and needs to be set by the DAI driver.
Signed-off-by: Lars-Peter Clausen lars@metafoo.de
Changes since v1:
- Use dma_get_max_seg_size() to get the maximum size of one period
- Assume that a DMA engine driver is able to support an infinite number of periods
- Increase min_period_bytes from 16 to 256.
include/sound/dmaengine_pcm.h | 2 ++ sound/soc/soc-generic-dmaengine-pcm.c | 55 ++++++++++++++++++++++++++++------- 2 files changed, 47 insertions(+), 10 deletions(-)
diff --git a/include/sound/dmaengine_pcm.h b/include/sound/dmaengine_pcm.h index f11c35c..83b2c3e 100644 --- a/include/sound/dmaengine_pcm.h +++ b/include/sound/dmaengine_pcm.h @@ -61,6 +61,7 @@ struct dma_chan *snd_dmaengine_pcm_get_chan(struct snd_pcm_substream *substream)
- @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.
- @fifo_size: FIFO size of the DAI controller in bytes
is this supposed to be DMA FIFO or I2S FIFO?
And second question for Takakshi or Mark. I see that this value ends up in usermode, what is the intented usage of this?
*/ struct snd_dmaengine_dai_dma_data { dma_addr_t addr; @@ -68,6 +69,7 @@ struct snd_dmaengine_dai_dma_data { u32 maxburst; unsigned int slave_id; void *filter_data;
- unsigned int fifo_size;
};
void snd_dmaengine_pcm_set_config_from_dai_data( diff --git a/sound/soc/soc-generic-dmaengine-pcm.c b/sound/soc/soc-generic-dmaengine-pcm.c index e29ec3c..c39e19e 100644 --- a/sound/soc/soc-generic-dmaengine-pcm.c +++ b/sound/soc/soc-generic-dmaengine-pcm.c @@ -36,6 +36,15 @@ static struct dmaengine_pcm *soc_platform_to_pcm(struct snd_soc_platform *p) return container_of(p, struct dmaengine_pcm, platform); }
+static struct device *dmaengine_dma_dev(struct dmaengine_pcm *pcm,
- struct snd_pcm_substream *substream)
+{
- if (!pcm->chan[substream->stream])
return NULL;- return pcm->chan[substream->stream]->device->dev;
+}
/**
- snd_dmaengine_pcm_prepare_slave_config() - Generic prepare_slave_config callback
- @substream: PCM substream
@@ -92,28 +101,54 @@ static int dmaengine_pcm_hw_params(struct snd_pcm_substream *substream, return snd_pcm_lib_malloc_pages(substream, params_buffer_bytes(params)); }
-static int dmaengine_pcm_open(struct snd_pcm_substream *substream) +static int dmaengine_pcm_set_runtime_hwparams(struct snd_pcm_substream *substream) { struct snd_soc_pcm_runtime *rtd = substream->private_data; struct dmaengine_pcm *pcm = soc_platform_to_pcm(rtd->platform);
- struct device *dma_dev = dmaengine_dma_dev(pcm, substream); struct dma_chan *chan = pcm->chan[substream->stream];
- struct snd_dmaengine_dai_dma_data *dma_data;
- struct dma_slave_caps dma_caps;
- struct snd_pcm_hardware hw; int ret;
- ret = snd_soc_set_runtime_hwparams(substream,
- if (pcm->config->pcm_hardware)
return snd_soc_set_runtime_hwparams(substream, pcm->config->pcm_hardware);
if (ret)
return ret;return snd_dmaengine_pcm_open(substream, chan);
- dma_data = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
- memset(&hw, 0, sizeof(hw));
- hw.info = SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID |
SNDRV_PCM_INFO_INTERLEAVED;- hw.periods_min = 2;
- hw.periods_max = UINT_MAX;
- hw.period_bytes_min = 256;
- hw.period_bytes_max = dma_get_max_seg_size(dma_dev);
I think you should check if the driver has set this, if not goto some default