Re: [PATCH] ASoC: SOF: compr: Add compress ops implementation

On 2022-01-13 5:13 PM, Daniel Baluta wrote:

From: Daniel Baluta daniel.baluta@nxp.com

Implement snd_compress_ops. There are a lot of similarities with PCM implementation.

For now we use sof_ipc_pcm_params to transfer compress parameters to SOF firmware.

This will be changed in the future once we either add new compress parameters to SOF or enhance existing sof_ipc_pcm_params structure to support all native compress params.

Signed-off-by: Daniel Baluta daniel.baluta@nxp.com

...

+static int create_page_table(struct snd_soc_component *component,

• 	     struct snd_compr_stream *cstream,
  

• 	     unsigned char *dma_area, size_t size)
  

+{

• struct snd_soc_pcm_runtime *rtd = cstream->private_data;
• struct snd_dma_buffer *dmab = cstream->runtime->dma_buffer_p;
• int dir = cstream->direction;
• struct snd_sof_pcm *spcm;

The layout of this declaration block is weird - it's neither a reversed-christmas-tree nor higher->lower complexity (e.g. structs -> primitives). Could you explain why it is shaped as is?

• spcm = snd_sof_find_spcm_dai(component, rtd);
• if (!spcm)

• return -EINVAL;
  

• return snd_sof_create_page_table(component->dev, dmab,

• 			 spcm->stream[dir].page_table.area, size);
  

+}

+int sof_compr_open(struct snd_soc_component *component,

•    struct snd_compr_stream *cstream)
  

+{

• struct snd_soc_pcm_runtime *rtd = cstream->private_data;
• struct snd_compr_runtime *runtime = cstream->runtime;

Making use of 'rtd' and 'runtime' simultaneously within a function make it less readable.

• struct sof_compr_stream *sstream;
• struct snd_sof_pcm *spcm;
• int dir;
• sstream = kzalloc(sizeof(*sstream), GFP_KERNEL);
• if (!sstream)

• return -ENOMEM;
  

• spcm = snd_sof_find_spcm_dai(component, rtd);
• if (!spcm) {

• kfree(sstream);
  

• return -EINVAL;
  

• }
• dir = cstream->direction;
• if (spcm->stream[dir].cstream) {

• kfree(sstream);
  

• return -EBUSY;
  

• }

Could you explain why this check is needed? i.e. Is is possible for compress stream to be opened "twice"?

• spcm->stream[dir].cstream = cstream;
• spcm->stream[dir].posn.host_posn = 0;
• spcm->stream[dir].posn.dai_posn = 0;
• spcm->prepared[dir] = false;
• runtime->private_data = sstream;
• return 0;

+}

+int sof_compr_free(struct snd_soc_component *component,

•    struct snd_compr_stream *cstream)
  

+{

• struct snd_sof_dev *sdev = snd_soc_component_get_drvdata(component);
• struct snd_soc_pcm_runtime *rtd = cstream->private_data;
• struct snd_compr_runtime *runtime = cstream->runtime;

Ditto.

• struct sof_compr_stream *sstream = runtime->private_data;
• struct sof_ipc_stream stream;
• struct sof_ipc_reply reply;
• struct snd_sof_pcm *spcm;
• int ret = 0;
• spcm = snd_sof_find_spcm_dai(component, rtd);
• if (!spcm)

• return -EINVAL;
  

• stream.hdr.size = sizeof(stream);
• stream.hdr.cmd = SOF_IPC_GLB_STREAM_MSG | SOF_IPC_STREAM_PCM_FREE;
• stream.comp_id = spcm->stream[cstream->direction].comp_id;
• if (spcm->prepared[cstream->direction]) {

• ret = sof_ipc_tx_message(sdev->ipc, stream.hdr.cmd,
  

• 			 &stream, sizeof(stream),
  

• 			 &reply, sizeof(reply));
  

• if (!ret)
  

• 	spcm->prepared[cstream->direction] = false;
  

Why is the assignment conditional? If IPC fails, is the ->prepared flag respected and addressed later on? It does not seem to happen here.

• }
• cancel_work_sync(&spcm->stream[cstream->direction].period_elapsed_work);
• spcm->stream[cstream->direction].cstream = NULL;
• kfree(sstream);
• return ret;

+}

+int sof_compr_set_params(struct snd_soc_component *component,

• 	 struct snd_compr_stream *cstream, struct snd_compr_params *params)
  

+{

• struct snd_sof_dev *sdev = snd_soc_component_get_drvdata(component);
• struct snd_soc_pcm_runtime *rtd_pcm = cstream->private_data;
• struct snd_compr_runtime *rtd = cstream->runtime;
• struct sof_compr_stream *sstream = rtd->private_data;
• struct sof_ipc_pcm_params_reply ipc_params_reply;
• struct sof_ipc_pcm_params pcm;
• struct snd_sof_pcm *spcm;
• int ret;
• spcm = snd_sof_find_spcm_dai(component, rtd_pcm);
• if (!spcm)

• return -EINVAL;
  

• cstream->dma_buffer.dev.type = SNDRV_DMA_TYPE_DEV_SG;
• cstream->dma_buffer.dev.dev = sdev->dev;
• ret = snd_compr_malloc_pages(cstream, rtd->buffer_size);
• if (ret < 0)

• return ret;
  

• create_page_table(component, cstream, rtd->dma_area, rtd->dma_bytes);

Shouldn't the result of create_page_table() be tested before moving on?

...

+int sof_compr_trigger(struct snd_soc_component *component,

•       struct snd_compr_stream *cstream, int cmd)
  

+{

• struct sof_ipc_stream stream;
• struct sof_ipc_reply reply;
• struct snd_soc_pcm_runtime *rtd = cstream->private_data;
• struct snd_sof_dev *sdev = snd_soc_component_get_drvdata(component);
• struct snd_sof_pcm *spcm;

Similarly to create_page_table() case, layout of this declaration block is weird. Perhaps I'm just unaware of the convention used within this directory.

...

+static int sof_compr_pointer(struct snd_soc_component *component,

• 	     struct snd_compr_stream *cstream,
  

• 	     struct snd_compr_tstamp *tstamp)
  

+{

• struct snd_compr_runtime *runtime = cstream->runtime;
• struct sof_compr_stream *sstream = runtime->private_data;

I'd suggest declaring single local variable instead. The 'runtime' one is unused except for the initial 'sstream' assignemnt.

• tstamp->sampling_rate = sstream->sample_rate;
• tstamp->copied_total = sstream->copied_total;
• return 0;

+}

...

diff --git a/sound/soc/sof/sof-priv.h b/sound/soc/sof/sof-priv.h index 087935192ce8..d001a762a866 100644 --- a/sound/soc/sof/sof-priv.h +++ b/sound/soc/sof/sof-priv.h @@ -108,6 +108,12 @@ enum sof_debugfs_access_type { SOF_DEBUGFS_ACCESS_D0_ONLY, };

+struct sof_compr_stream {

• unsigned int copied_total;
• unsigned int sample_rate;
• size_t posn_offset;

+};

Some streaming-related PCM structs follow snd_sof_xxx naming pattern instead, e.g.: snd_sof_pcm. Is the naming convention for compress streams seen here intentional?

• struct snd_sof_dev; struct snd_sof_ipc_msg; struct snd_sof_ipc;