On 03/13/2014 10:18 AM, Peter Ujfalusi wrote: [...]
+static const struct snd_pcm_hardware edma_pcm_hardware = {
- .info = SNDRV_PCM_INFO_MMAP |
SNDRV_PCM_INFO_MMAP_VALID |SNDRV_PCM_INFO_BATCH |SNDRV_PCM_INFO_PAUSE | SNDRV_PCM_INFO_RESUME |SNDRV_PCM_INFO_INTERLEAVED,- .buffer_bytes_max = 128 * 1024,
- .period_bytes_min = 32,
- .period_bytes_max = 64 * 1024,
- .periods_min = 2,
- .periods_max = 19, /* Limit by edma dmaengine driver */
+};
The idea is that we can auto-discover all the things using the dma_slave_caps API. Too bad we removed the possibility to specify the maximum number of segments from the API. Maybe we need to add it back. Is the 19 a hard-limit or could it be worked around by software in the dmaengine driver?
+static const struct snd_dmaengine_pcm_config edma_dmaengine_pcm_config = {
- .pcm_hardware = &edma_pcm_hardware,
- .prepare_slave_config = snd_dmaengine_pcm_prepare_slave_config,
- .prealloc_buffer_size = 128 * 1024,
Unless there is a very good reason for exactly this size, just leave it 0 and let the generic dmaengine driver use the default.
+};
+static const struct snd_dmaengine_pcm_config edma_compat_dmaengine_pcm_config = {
- .pcm_hardware = &edma_pcm_hardware,
- .prepare_slave_config = snd_dmaengine_pcm_prepare_slave_config,
- .compat_filter_fn = edma_filter_fn,
- .prealloc_buffer_size = 128 * 1024,
+};
There is no need for different configs for DT and non-DT.
+int edma_pcm_platform_register(struct device *dev) +{
- if (dev->of_node)
return snd_dmaengine_pcm_register(dev,&edma_dmaengine_pcm_config,SND_DMAENGINE_PCM_FLAG_NO_RESIDUE);
Since the edma dmaengine driver implements the slave cap API there is no need to manually specify SND_DMAENGINE_PCM_FLAG_NO_RESIDUE manually. But since the edma driver sets the granularity to DMA_RESIDUE_GRANULARITY_DESCRIPTOR in this case the generic dmaengine will not set SND_DMAENGINE_PCM_FLAG_NO_RESIDUE automatically since it assumes that the dmaengine driver is capable of properly reporting the DMA position.
- else
return snd_dmaengine_pcm_register(dev,&edma_compat_dmaengine_pcm_config,SND_DMAENGINE_PCM_FLAG_NO_RESIDUE |SND_DMAENGINE_PCM_FLAG_NO_DT |SND_DMAENGINE_PCM_FLAG_COMPAT);
If you set the flags to just SND_DMAENGINE_PCM_FLAG_COMPAT it will do the right thing in the generic dmaengine driver depending on whether dev->of_node is set or not.
There is also a devm_ version of snd_dmaengine_pcm_register() it probably makes sense to use it here.