From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jyri Sarha Subject: Re: [PATCH v2] ASoC: davinci-mcasp: Choose PCM driver based on configured DMA controller Date: Tue, 2 Jun 2015 23:04:46 +0300 Message-ID: <556E0C5E.6040603@ti.com> References: <7230089f10ea27a9bd76eb8bfffcef754e71f274.1433252849.git.jsarha@ti.com> <556DD6EB.5010504@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <556DD6EB.5010504@ti.com> Sender: linux-omap-owner@vger.kernel.org To: Misael Lopez Cruz , alsa-devel@alsa-project.org, devicetree@vger.kernel.org, linux-omap@vger.kernel.org Cc: peter.ujfalusi@ti.com, broonie@kernel.org, liam.r.girdwood@linux.intel.com, bcousson@baylibre.com List-Id: alsa-devel@alsa-project.org On 06/02/15 19:16, Misael Lopez Cruz wrote: > Jyri, > > On 06/02/2015 08:49 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 >> --- >> Changes since first patch version: >> - Change enum names from MCASP_?DMA to PCM_?DMA >> - Return PCM_EDMA if !mcasp->dev->of_node >> - Do not ignore possible error code returned by >> davinci_mcasp_get_dma_type() >> >> sound/soc/davinci/davinci-mcasp.c | 68 >> +++++++++++++++++++++++++++++++++------ >> 1 file changed, 58 insertions(+), 10 deletions(-) >> >> diff --git a/sound/soc/davinci/davinci-mcasp.c >> b/sound/soc/davinci/davinci-mcasp.c >> index d793494..3b78c3e 100644 >> --- a/sound/soc/davinci/davinci-mcasp.c >> +++ b/sound/soc/davinci/davinci-mcasp.c >> @@ -1565,6 +1565,49 @@ static int >> davinci_mcasp_init_ch_constraints(struct davinci_mcasp *mcasp) >> return ret; >> } >> >> +enum { >> + PCM_EDMA, >> + PCM_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 = PCM_EDMA; >> + >> + if (!mcasp->dev->of_node) >> + return PCM_EDMA; >> + >> + tmp = mcasp->dma_data[SNDRV_PCM_STREAM_PLAYBACK].filter_data; >> + chan = dma_request_slave_channel_reason(mcasp->dev, tmp); >> + 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); > > I wonder how this is going to play out when the DMA crossbar is present > (i.e. dra7 family). > > In that case, isn't the 'compatible' string here that of the DMA > crossbar (not the one from the DMA controller)? That is exactly why I am requesting a channel and going from there. The DMA router will do its thing in the middle and the device pointer found via the returned dma_chan is pointing at the actual DMA controller. I have tested the code on am57xx-beagle-x15, which is also using the DMA crossbar. > >> + else >> + dev_dbg(mcasp->dev, "DMA controller has no of-node\n"); >> + >> + 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 PCM_SDMA; >> + >> + return PCM_EDMA; >> +} >> + >> static int davinci_mcasp_probe(struct platform_device *pdev) >> { >> struct snd_dmaengine_dai_dma_data *dma_data; >> @@ -1763,27 +1806,32 @@ static int davinci_mcasp_probe(struct >> platform_device *pdev) >> if (ret != 0) >> goto err; >> >> - switch (mcasp->version) { >> + ret = davinci_mcasp_get_dma_type(mcasp); >> + switch (ret) { >> + case PCM_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"); >> + ret = -EINVAL; >> #endif >> + break; >> + case PCM_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"); >> + ret = -EINVAL; >> #endif >> + break; >> + case -EPROBE_DEFER: >> + break; >> default: >> - dev_err(&pdev->dev, "Invalid McASP version: %d\n", >> - mcasp->version); >> - ret = -EINVAL; >> + dev_err(&pdev->dev, "No DMA controller found (%d)\n", ret); >> break; >> } >> >>