Hi Yang Yingliang,

Still some improvements to be done on this patch. If one of the dma channel is failed, we should fallback that channel to PIO.

Something like below. I will post a new patch after testing this.

ssi->playback.transfer = rz_ssi_pio_send; ssi->capture.transfer = rz_ssi_pio_recv;

/* Detect DMA support */ ret = rz_ssi_dma_request(ssi, &pdev->dev); if (ret < 0) { dev_warn(&pdev->dev, "DMA not available, using PIO\n"); } else { dev_info(&pdev->dev, "DMA enabled"); if (ssi->playback.dma_ch) ssi->playback.transfer = rz_ssi_dma_transfer; if (ssi->capture.dma_ch) ssi->capture.transfer = rz_ssi_dma_transfer; }

Regards, Biju

Subject: RE: [PATCH -next] ASoC: sh: rz-ssi: Fix return value check in rz_ssi_dma_request()

Hi Yang Yingliang,

Thanks for your patch.

Already I have posted a patch for fixing it.

https://patchwork.kernel.org/project/alsa- devel/patch/20210814180120.18082-1-biju.das.jz@bp.renesas.com/

Since you posted a similar patch as Reported-by: Hulk Robot hulkci@huawei.com, I am adding my Rb tag for this patch.

Regards, Biju

...

-----Original Message----- From: Yang Yingliang yangyingliang@huawei.com Sent: 17 August 2021 04:00 To: linux-kernel@vger.kernel.org; alsa-devel@alsa-project.org Cc: broonie@kernel.org; Biju Das biju.das.jz@bp.renesas.com; Prabhakar Mahadev Lad prabhakar.mahadev-lad.rj@bp.renesas.com; lgirdwood@gmail.com Subject: [PATCH -next] ASoC: sh: rz-ssi: Fix return value check in rz_ssi_dma_request()

In case of error, the function dma_request_chan() returns ERR_PTR() and never returns NULL. Set 'dma_ch' to NULL, if dma_request_chan() returns error, so the code using 'dma_ch' can work correctly.

Fixes: 26ac471c5354 ("ASoC: sh: rz-ssi: Add SSI DMAC support") Reported-by: Hulk Robot hulkci@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com

Reviewed-by: Biju Das biju.das.jz@bp.renesas.com

...

---

sound/soc/sh/rz-ssi.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/sound/soc/sh/rz-ssi.c b/sound/soc/sh/rz-ssi.c index ea8d33ede5d2..5ec78fd94d94 100644 --- a/sound/soc/sh/rz-ssi.c +++ b/sound/soc/sh/rz-ssi.c @@ -676,11 +676,17 @@ static void rz_ssi_release_dma_channels(struct rz_ssi_priv *ssi) static int rz_ssi_dma_request(struct rz_ssi_priv *ssi, struct device *dev) { ssi->playback.dma_ch = dma_request_chan(dev, "tx");

• if (IS_ERR(ssi->playback.dma_ch))

• ssi->playback.dma_ch = NULL;
  

  ssi->capture.dma_ch = dma_request_chan(dev, "rx");
• if (IS_ERR(ssi->capture.dma_ch))

• ssi->capture.dma_ch = NULL;
  

  if (!ssi->playback.dma_ch && !ssi->capture.dma_ch) { ssi->playback.dma_ch = dma_request_chan(dev, "rt");

• if (!ssi->playback.dma_ch)
  

• if (IS_ERR(ssi->playback.dma_ch)) {
  

• 	ssi->playback.dma_ch = NULL;
  goto no_dma;
  

• }
  
  

  ssi->dma_rt = true; }

-- 2.25.1