On 06/02/2015 11:58 AM, Jyri Sarha wrote:
> Find the configured DMA controller by asking for a DMA channel in the
> probe phase and releasing it right after. The controller device can be
> found via the dma_chan struct and the controller is recognized from
> the compatible property of its device node. The patch assumes EDMA if
> there is no device node.
>
> Signed-off-by: Jyri Sarha <jsarha@xxxxxx>
> ---
> sound/soc/davinci/davinci-mcasp.c | 61 ++++++++++++++++++++++++++++++++-------
> 1 file changed, 51 insertions(+), 10 deletions(-)
>
> diff --git a/sound/soc/davinci/davinci-mcasp.c b/sound/soc/davinci/davinci-mcasp.c
> index d793494..5bc2712 100644
> --- a/sound/soc/davinci/davinci-mcasp.c
> +++ b/sound/soc/davinci/davinci-mcasp.c
> @@ -1565,6 +1565,46 @@ static int davinci_mcasp_init_ch_constraints(struct davinci_mcasp *mcasp)
> return ret;
> }
>
> +enum {
> + MCASP_EDMA = 1,
Why start from 1?
I'm not sure about the name. It somehow implies that McASP has something to do
with the dma engine.
MCASP_SERVICED_BY_E/SDMA
PLATFORM_USES_E/SDMA
I can not come up with a decent name :(
> + MCASP_SDMA,
> +};
> +static const char *sdma_prefix = "ti,omap";
> +
> +static int davinci_mcasp_get_dma_type(struct davinci_mcasp *mcasp)
> +{
> + struct dma_chan *chan;
> + const char *tmp;
> + int ret = MCASP_EDMA;
> +
> + tmp = mcasp->dma_data[SNDRV_PCM_STREAM_PLAYBACK].filter_data;
> + chan = dma_request_slave_channel_reason(mcasp->dev, tmp);
this will return with error in case of !dev->of_node.
The first check should be:
if (!mcasp->dev->of_node)
return MCASP_EDMA;
since we can only boot in legacy mode with daVinci devices and they are using
eDMA.
> + if (IS_ERR(chan)) {
> + if (PTR_ERR(chan) != -EPROBE_DEFER)
> + dev_err(mcasp->dev,
> + "Can't verify DMA configuration (%ld)\n",
> + PTR_ERR(chan));
> + return PTR_ERR(chan);
> + }
> + BUG_ON(!chan->device || !chan->device->dev);
> +
> + if (chan->device->dev->of_node)
> + ret = of_property_read_string(chan->device->dev->of_node,
> + "compatible", &tmp);
> + else
> + dev_dbg(mcasp->dev, "DMA controller has no of-node\n");
Now this is not likely to happen...
> +
> + dma_release_channel(chan);
> + if (ret)
> + return ret;
> +
> + dev_dbg(mcasp->dev, "DMA controller compatible = \"%s\"\n", tmp);
> + if (!strncmp(tmp, sdma_prefix, strlen(sdma_prefix)))
> + return MCASP_SDMA;
> +
> + return MCASP_EDMA;
> +}
> +
> static int davinci_mcasp_probe(struct platform_device *pdev)
> {
> struct snd_dmaengine_dai_dma_data *dma_data;
> @@ -1763,27 +1803,28 @@ static int davinci_mcasp_probe(struct platform_device *pdev)
> if (ret != 0)
> goto err;
>
> - switch (mcasp->version) {
> + ret = -EINVAL;
Why? What was the problem with setting the ret in the default case?
> + switch (davinci_mcasp_get_dma_type(mcasp)) {
> + case MCASP_EDMA:
> #if IS_BUILTIN(CONFIG_SND_EDMA_SOC) || \
> (IS_MODULE(CONFIG_SND_DAVINCI_SOC_MCASP) && \
> IS_MODULE(CONFIG_SND_EDMA_SOC))
> - case MCASP_VERSION_1:
> - case MCASP_VERSION_2:
> - case MCASP_VERSION_3:
> ret = edma_pcm_platform_register(&pdev->dev);
> - break;
> +#else
> + dev_err(&pdev->dev, "Missing SND_EDMA_SOC\n");
> #endif
> + break;
> + case MCASP_SDMA:
> #if IS_BUILTIN(CONFIG_SND_OMAP_SOC) || \
> (IS_MODULE(CONFIG_SND_DAVINCI_SOC_MCASP) && \
> IS_MODULE(CONFIG_SND_OMAP_SOC))
> - case MCASP_VERSION_4:
> ret = omap_pcm_platform_register(&pdev->dev);
> - break;
> +#else
> + dev_err(&pdev->dev, "Missing SND_SDMA_SOC\n");
> #endif
> + break;
> default:
> - dev_err(&pdev->dev, "Invalid McASP version: %d\n",
> - mcasp->version);
> - ret = -EINVAL;
> + dev_err(&pdev->dev, "No DMA controller found\n");
> break;
> }
>
>
--
Péter
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