Re: [PATCH v2 2/2] sound: lpass-platform: Move dma channel allocation to pcmops

[Srinivas Kandagatla]

On 14/06/16 13:49, Kenneth Westfield wrote:
> On Tue, Jun 14, 2016 at 09:30:03AM +0100, Srinivas Kandagatla wrote:
> > Move dma channel allocations to pcmops open and close functions. Reason
> > to do this is that, lpass_platform_pcm_free() accesses snd_soc_pcm_runtime
> > via substream->private data, However By this time runtimes are already
> > freed as part of soc_cleanup_card_resources() sequence.
> >
> > This patch moves the channel allocations/deallocations to pcmops open()
> > and close() respectively, where the code has valid snd_soc_pcm_runtime.
>
> > ---
> >   sound/soc/qcom/lpass-platform.c | 155 +++++++++++++++++++---------------------
> >   1 file changed, 74 insertions(+), 81 deletions(-)
> >
> > diff --git a/sound/soc/qcom/lpass-platform.c b/sound/soc/qcom/lpass-platform.c
> > index db000c6..3bd2cd6 100644
> > --- a/sound/soc/qcom/lpass-platform.c
> > +++ b/sound/soc/qcom/lpass-platform.c
> > @@ -61,7 +61,36 @@ static int lpass_platform_pcmops_open(struct snd_pcm_substream *substream)
>
> > +		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
> > +			pcm_data->rdma_ch = ch;
> > +			reg =  LPAIF_RDMACTL_REG(v, ch);
>
> Spacing.
Ok, s/  / /
> > +		} else {
> > +			pcm_data->wrdma_ch = ch;
> > +			reg =  LPAIF_WRDMACTL_REG(v, ch);
>
> Spacing.
Yep
> > +static int lpass_platform_pcmops_close(struct snd_pcm_substream *substream)
> > +{
> > +	struct snd_soc_pcm_runtime *soc_runtime = substream->private_data;
> > +	struct lpass_pcm_data *pcm_data = snd_soc_pcm_get_drvdata(soc_runtime);
> > +	struct lpass_data *drvdata =
> > +		snd_soc_platform_get_drvdata(soc_runtime->platform);
> > +	struct lpass_variant *v = drvdata->variant;
> > +	int ch;
> > +
> > +	if (v->free_dma_channel) {
> > +		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
> > +			ch = pcm_data->rdma_ch;
> > +		else
> > +			ch = pcm_data->wrdma_ch;
> > +
> > +		if (ch >= 0)
> > +			v->free_dma_channel(drvdata, ch);
> > +	}
>
> Since this is being moved from free() to close(), drvdata->substream[ch]
> should be set to NULL.  Otherwise, the array could fill up as the PCM is
> opened/closed.
Yep, we could do that.
> > @@ -471,14 +529,12 @@ static int lpass_platform_pcm_new(struct snd_soc_pcm_runtime *soc_runtime)
> >   	struct snd_pcm *pcm = soc_runtime->pcm;
> >   	struct snd_pcm_substream *psubstream, *csubstream;
> >   	struct snd_soc_dai *cpu_dai = soc_runtime->cpu_dai;
> > -	struct lpass_data *drvdata =
> > -		snd_soc_platform_get_drvdata(soc_runtime->platform);
> > -	struct lpass_variant *v = drvdata->variant;
> > -	int ret = -EINVAL;
> > +	struct device *dev = soc_runtime->platform->dev;
> >   	struct lpass_pcm_data *data;
> >   	size_t size = lpass_platform_pcm_hardware.buffer_bytes_max;
> > +	int ret = -EINVAL;
> >
> > -	data = devm_kzalloc(soc_runtime->dev, sizeof(*data), GFP_KERNEL);
> > +	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
>
> Is the reason for changing the dev pointer similar to why it was changed
> for snd_dma_alloc_pages() below?
Yep, Only reason is that I can fit stuff in single line.
> > +		ret = snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, dev, size,
> > +					  &psubstream->dma_buffer);
> >   		if (ret) {
> > -			dev_err(soc_runtime->dev,
> > -				"%s() error writing to rdmactl reg: %d\n",
> > -				__func__, ret);
> > -			goto capture_alloc_err;
> > +			dev_err(dev, "can't alloc playback dma buffer\n");
>
> Print the return value.
Ok.
> > +		ret = snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, dev, size,
> > +					  &csubstream->dma_buffer);
> >   		if (ret) {
> > -			dev_err(soc_runtime->dev,
> > -				"%s() error writing to wrdmactl reg: %d\n",
> > -				__func__, ret);
> > -			goto capture_reg_err;
> > +			dev_err(dev, "can't alloc capture dma buffer\n");
>
> Ditto.
Ok.
>

Thanks,
srini