Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Message-ID: <0866cd8cdb0c22f0b2a6814c4dafa29202aad5f3.camel@pengutronix.de>
Subject: Re: [PATCH] ASoC: fsl: imx-pcm-dma: Don't request dma channel in
 probe
From:   Lucas Stach <l.stach@pengutronix.de>
To:     Shengjiu Wang <shengjiu.wang@nxp.com>, timur@kernel.org,
        nicoleotsuka@gmail.com, Xiubo.Lee@gmail.com, festevam@gmail.com,
        lgirdwood@gmail.com, broonie@kernel.org, perex@perex.cz,
        tiwai@suse.com, shawnguo@kernel.org, s.hauer@pengutronix.de,
        kernel@pengutronix.de, linux-imx@nxp.com, sumit.semwal@linaro.org,
        alsa-devel@alsa-project.org, linuxppc-dev@lists.ozlabs.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org,
        linaro-mm-sig@lists.linaro.org
Date:   Tue, 19 May 2020 12:01:59 +0200
In-Reply-To: <1589881301-4143-1-git-send-email-shengjiu.wang@nxp.com>
References: <1589881301-4143-1-git-send-email-shengjiu.wang@nxp.com>
Content-Type: text/plain; charset="UTF-8"
User-Agent: Evolution 3.36.2 (3.36.2-1.fc32) 
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Am Dienstag, den 19.05.2020, 17:41 +0800 schrieb Shengjiu Wang:
> There are two requirements that we need to move the request
> of dma channel from probe to open.

How do you handle -EPROBE_DEFER return code from the channel request if
you don't do it in probe?

> - When dma device binds with power-domains, the power will
> be enabled when we request dma channel. If the request of dma
> channel happen on probe, then the power-domains will be always
> enabled after kernel boot up,  which is not good for power
> saving,  so we need to move the request of dma channel to .open();

This is certainly something which could be fixed in the dmaengine
driver.

> - With FE-BE case, if the dma channel is requested in probe,
> then there will be below issue, which is caused by that the
> dma channel will be requested duplicately

Why is this requested a second time? Is this just some missing cleanup
on a deferred probe path?

Regards,
Lucas

> [  638.906268] sysfs: cannot create duplicate filename '/devices/soc0/soc/2000000.bus/2000000.spba-bus/2024000.esai/dma:tx'
> [  638.919061] CPU: 1 PID: 673 Comm: aplay Not tainted 5.7.0-rc1-12956-gfc64b2585593 #287
> [  638.927113] Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
> [  638.933690] [<c0110dd8>] (unwind_backtrace) from [<c010b8ec>] (show_stack+0x10/0x14)
> [  638.941464] [<c010b8ec>] (show_stack) from [<c0557fc0>] (dump_stack+0xe4/0x118)
> [  638.948808] [<c0557fc0>] (dump_stack) from [<c032aeb4>] (sysfs_warn_dup+0x50/0x64)
> [  638.956406] [<c032aeb4>] (sysfs_warn_dup) from [<c032b1a8>] (sysfs_do_create_link_sd+0xc8/0xd4)
> [  638.965134] [<c032b1a8>] (sysfs_do_create_link_sd) from [<c05dc668>] (dma_request_chan+0xb0/0x210)
> [  638.974120] [<c05dc668>] (dma_request_chan) from [<c05dc7d0>] (dma_request_slave_channel+0x8/0x14)
> [  638.983111] [<c05dc7d0>] (dma_request_slave_channel) from [<c09d5548>] (fsl_asrc_dma_hw_params+0x1e0/0x438)
> [  638.992881] [<c09d5548>] (fsl_asrc_dma_hw_params) from [<c09c1654>] (soc_pcm_hw_params+0x4a0/0x6a8)
> [  639.001952] [<c09c1654>] (soc_pcm_hw_params) from [<c09c39d4>] (dpcm_fe_dai_hw_params+0x70/0xe4)
> [  639.010765] [<c09c39d4>] (dpcm_fe_dai_hw_params) from [<c099b274>] (snd_pcm_hw_params+0x158/0x418)
> [  639.019750] [<c099b274>] (snd_pcm_hw_params) from [<c099c5a0>] (snd_pcm_ioctl+0x734/0x183c)
> [  639.028129] [<c099c5a0>] (snd_pcm_ioctl) from [<c029ff94>] (ksys_ioctl+0x2ac/0xb98)
> [  639.035812] [<c029ff94>] (ksys_ioctl) from [<c0100080>] (ret_fast_syscall+0x0/0x28)
> [  639.043490] Exception stack(0xec529fa8 to 0xec529ff0)
> [  639.048565] 9fa0:                   bee84650 01321870 00000004 c25c4111 bee84650 0002000f
> [  639.056766] 9fc0: bee84650 01321870 01321820 00000036 00001f40 00000000 0002c2f8 00000003
> [  639.064964] 9fe0: b6f483fc bee8451c b6ee2655 b6e1dcf8
> [  639.070339] fsl-esai-dai 2024000.esai: Cannot create DMA dma:tx symlink
> 
> Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
> ---
>  sound/soc/fsl/imx-pcm-dma.c | 173 +++++++++++++++++++++++++++++++++---
>  1 file changed, 159 insertions(+), 14 deletions(-)
> 
> diff --git a/sound/soc/fsl/imx-pcm-dma.c b/sound/soc/fsl/imx-pcm-dma.c
> index 04a9bc749016..dae53b384df4 100644
> --- a/sound/soc/fsl/imx-pcm-dma.c
> +++ b/sound/soc/fsl/imx-pcm-dma.c
> @@ -11,6 +11,7 @@
>  #include <linux/dmaengine.h>
>  #include <linux/types.h>
>  #include <linux/module.h>
> +#include <linux/dma-mapping.h>
>  
>  #include <sound/core.h>
>  #include <sound/pcm.h>
> @@ -29,24 +30,168 @@ static bool filter(struct dma_chan *chan, void *param)
>  	return true;
>  }
>  
> -static const struct snd_dmaengine_pcm_config imx_dmaengine_pcm_config = {
> -	.prepare_slave_config = snd_dmaengine_pcm_prepare_slave_config,
> -	.compat_filter_fn = filter,
> -};
> +static int imx_pcm_hw_params(struct snd_soc_component *component,
> +			     struct snd_pcm_substream *substream,
> +			     struct snd_pcm_hw_params *params)
> +{
> +	struct snd_pcm_runtime *runtime = substream->runtime;
> +	struct snd_soc_pcm_runtime *rtd = substream->private_data;
> +	struct snd_soc_dai *cpu_dai = asoc_rtd_to_cpu(rtd, 0);
> +	struct snd_dmaengine_dai_dma_data *dma_data;
> +	struct dma_slave_config config;
> +	struct dma_chan *chan;
> +	int ret = 0;
>  
> -int imx_pcm_dma_init(struct platform_device *pdev, size_t size)
> +	snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);
> +	runtime->dma_bytes = params_buffer_bytes(params);
> +
> +	chan = snd_dmaengine_pcm_get_chan(substream);
> +	if (!chan)
> +		return -EINVAL;
> +
> +	ret = snd_hwparams_to_dma_slave_config(substream, params, &config);
> +	if (ret)
> +		return ret;
> +
> +	dma_data = snd_soc_dai_get_dma_data(cpu_dai, substream);
> +	if (!dma_data)
> +		return -EINVAL;
> +
> +	snd_dmaengine_pcm_set_config_from_dai_data(substream,
> +						   dma_data,
> +						   &config);
> +	return dmaengine_slave_config(chan, &config);
> +}
> +
> +static int imx_pcm_hw_free(struct snd_soc_component *component,
> +			   struct snd_pcm_substream *substream)
>  {
> -	struct snd_dmaengine_pcm_config *config;
> +	snd_pcm_set_runtime_buffer(substream, NULL);
> +	return 0;
> +}
> +
> +static snd_pcm_uframes_t imx_pcm_pointer(struct snd_soc_component *component,
> +					 struct snd_pcm_substream *substream)
> +{
> +	return snd_dmaengine_pcm_pointer(substream);
> +}
> +
> +static int imx_pcm_trigger(struct snd_soc_component *component,
> +			   struct snd_pcm_substream *substream, int cmd)
> +{
> +	return snd_dmaengine_pcm_trigger(substream, cmd);
> +}
> +
> +static int imx_pcm_open(struct snd_soc_component *component,
> +			struct snd_pcm_substream *substream)
> +{
> +	struct snd_soc_pcm_runtime *rtd = substream->private_data;
> +	bool tx = substream->stream == SNDRV_PCM_STREAM_PLAYBACK;
> +	struct snd_soc_dai *cpu_dai = asoc_rtd_to_cpu(rtd, 0);
> +	struct snd_dmaengine_dai_dma_data *dma_data;
> +	struct device *dev = component->dev;
> +	struct snd_pcm_hardware hw;
> +	struct dma_chan *chan;
> +	int ret;
> +
> +	ret = snd_pcm_hw_constraint_integer(substream->runtime,
> +					    SNDRV_PCM_HW_PARAM_PERIODS);
> +	if (ret < 0) {
> +		dev_err(dev, "failed to set pcm hw params periods\n");
> +		return ret;
> +	}
> +
> +	dma_data = snd_soc_dai_get_dma_data(cpu_dai, substream);
> +	if (!dma_data)
> +		return -EINVAL;
> +
> +	chan = dma_request_slave_channel(cpu_dai->dev, tx ? "tx" : "rx");
> +	if (!chan) {
> +		/* Try to request channel using compat_filter_fn */
> +		chan = snd_dmaengine_pcm_request_channel(filter,
> +							 dma_data->filter_data);
> +		if (!chan)
> +			return -ENXIO;
> +	}
>  
> -	config = devm_kzalloc(&pdev->dev,
> -			sizeof(struct snd_dmaengine_pcm_config), GFP_KERNEL);
> -	if (!config)
> -		return -ENOMEM;
> -	*config = imx_dmaengine_pcm_config;
> +	ret = snd_dmaengine_pcm_open(substream, chan);
> +	if (ret)
> +		goto pcm_open_fail;
>  
> -	return devm_snd_dmaengine_pcm_register(&pdev->dev,
> -		config,
> -		SND_DMAENGINE_PCM_FLAG_COMPAT);
> +	memset(&hw, 0, sizeof(hw));
> +	hw.info = SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID |
> +			SNDRV_PCM_INFO_INTERLEAVED;
> +	hw.periods_min = 2;
> +	hw.periods_max = UINT_MAX;
> +	hw.period_bytes_min = 256;
> +	hw.period_bytes_max = dma_get_max_seg_size(chan->device->dev);
> +	hw.buffer_bytes_max = IMX_DEFAULT_DMABUF_SIZE;
> +	hw.fifo_size = dma_data->fifo_size;
> +
> +	/* Refine the hw according to caps of DMA. */
> +	ret = snd_dmaengine_pcm_refine_runtime_hwparams(substream,
> +							dma_data,
> +							&hw,
> +							chan);
> +	if (ret < 0)
> +		goto refine_runtime_hwparams_fail;
> +
> +	snd_soc_set_runtime_hwparams(substream, &hw);
> +
> +	/* Support allocate memory from IRAM */
> +	ret = snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV_IRAM,
> +				  chan->device->dev,
> +				  hw.buffer_bytes_max,
> +				  &substream->dma_buffer);
> +	if (ret < 0)
> +		goto alloc_pagas_fail;
> +
> +	return 0;
> +
> +alloc_pagas_fail:
> +refine_runtime_hwparams_fail:
> +	snd_dmaengine_pcm_close(substream);
> +pcm_open_fail:
> +	dma_release_channel(chan);
> +
> +	return ret;
> +}
> +
> +static int imx_pcm_close(struct snd_soc_component *component,
> +			 struct snd_pcm_substream *substream)
> +{
> +	if (substream) {
> +		snd_dma_free_pages(&substream->dma_buffer);
> +		substream->dma_buffer.area = NULL;
> +		substream->dma_buffer.addr = 0;
> +	}
> +
> +	return snd_dmaengine_pcm_close_release_chan(substream);
> +}
> +
> +static int imx_pcm_new(struct snd_soc_component *component,
> +		       struct snd_soc_pcm_runtime *rtd)
> +{
> +	struct snd_card *card = rtd->card->snd_card;
> +
> +	return dma_coerce_mask_and_coherent(card->dev, DMA_BIT_MASK(32));
> +}
> +
> +static const struct snd_soc_component_driver imx_pcm_component = {
> +	.name           = "imx-pcm-dma",
> +	.pcm_construct	= imx_pcm_new,
> +	.open		= imx_pcm_open,
> +	.close		= imx_pcm_close,
> +	.hw_params	= imx_pcm_hw_params,
> +	.hw_free	= imx_pcm_hw_free,
> +	.trigger	= imx_pcm_trigger,
> +	.pointer	= imx_pcm_pointer,
> +};
> +
> +int imx_pcm_dma_init(struct platform_device *pdev, size_t size)
> +{
> +	return devm_snd_soc_register_component(&pdev->dev,
> +					       &imx_pcm_component, NULL, 0);
>  }
>  EXPORT_SYMBOL_GPL(imx_pcm_dma_init);
>