At Wed, 2 Jul 2014 16:29:21 +0300,
Peter Ujfalusi wrote:
>
> Based on the dma_slave_caps's addr_widths queried from the dma driver
> prepare the hw.formats mask to include only formats which is supported by
> the DMA engine.
> In case the dma driver does not implement the slave_caps the default
> assumption is that it supports 1, 2 and 4 bytes widths.
>
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@xxxxxx>
> ---
> sound/soc/soc-generic-dmaengine-pcm.c | 26 +++++++++++++++++++++++++-
> 1 file changed, 25 insertions(+), 1 deletion(-)
>
> diff --git a/sound/soc/soc-generic-dmaengine-pcm.c b/sound/soc/soc-generic-dmaengine-pcm.c
> index 5bace124ef43..c295e1754d1a 100644
> --- a/sound/soc/soc-generic-dmaengine-pcm.c
> +++ b/sound/soc/soc-generic-dmaengine-pcm.c
> @@ -119,7 +119,10 @@ static int dmaengine_pcm_set_runtime_hwparams(struct snd_pcm_substream *substrea
> struct snd_dmaengine_dai_dma_data *dma_data;
> struct dma_slave_caps dma_caps;
> struct snd_pcm_hardware hw;
> - int ret;
> + u32 addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
> + BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
> + BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
> + int i, ret;
>
> if (pcm->config && pcm->config->pcm_hardware)
> return snd_soc_set_runtime_hwparams(substream,
> @@ -146,6 +149,27 @@ static int dmaengine_pcm_set_runtime_hwparams(struct snd_pcm_substream *substrea
> hw.info |= SNDRV_PCM_INFO_PAUSE | SNDRV_PCM_INFO_RESUME;
> if (dma_caps.residue_granularity <= DMA_RESIDUE_GRANULARITY_SEGMENT)
> hw.info |= SNDRV_PCM_INFO_BATCH;
> +
> + if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
> + addr_widths = dma_caps.dstn_addr_widths;
> + else
> + addr_widths = dma_caps.src_addr_widths;
> + }
> +
> + /*
> + * Prepare formats mask for valid/allowed sample types. If the dma does
> + * not have support for the given physical word size, it needs to be
> + * masked out so user space can not use the format which produces
> + * corrupted audio.
> + * In case the dma driver does not implement the slave_caps the default
> + * assumption is that it supports 1, 2 and 4 bytes widths.
> + */
> + for (i = 0; i <= SNDRV_PCM_FORMAT_LAST; i++) {
> + int bits = snd_pcm_format_physical_width(i);
Better to add a negative value check. Some formats return -EINVAL.
> +
> + /* Enable only samples with DMA supported physical widths */
> + if (addr_widths & BIT(bits / 8))
Just nitpicking: Using BIT() for 32bit int isn't always a wise choice
since BIT() is defined as unsigned long. This is a generic problem,
though, as we see many codes using BIT() wrongly (and thus get
compiler warnings on 64bit machines). We should introduce a new macro
for 32bit int...
Takashi
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