Re: [PATCH] dmaengine: altera-msgdma: fail probe when reset times out

[Frank Li]

On Tue, Jun 23, 2026 at 02:05:54PM +0800, Pengpeng Hou wrote:
> msgdma_probe() resets the controller before publishing the DMA device
> and OF DMA provider, but msgdma_reset() only logs a timeout and then
> continues to enable the controller and mark it idle.
>
> If the reset bit never clears, the driver can still register a DMA
> engine backed by a controller that did not leave reset. Return the
> readl_poll_timeout() error from msgdma_reset() and abort probe on reset
> failure.
>
> Signed-off-by: Pengpeng Hou <pengpeng@xxxxxxxxxxx>
> ---

Reviewed-by: Frank Li <Frank.Li@xxxxxxx>

>  drivers/dma/altera-msgdma.c | 11 ++++++++---
>  1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/dma/altera-msgdma.c b/drivers/dma/altera-msgdma.c
> index b46999c81df0..f60a4e86a246 100644
> --- a/drivers/dma/altera-msgdma.c
> +++ b/drivers/dma/altera-msgdma.c
> @@ -466,7 +466,7 @@ static int msgdma_dma_config(struct dma_chan *dchan,
>  	return 0;
>  }
>
> -static void msgdma_reset(struct msgdma_device *mdev)
> +static int msgdma_reset(struct msgdma_device *mdev)
>  {
>  	u32 val;
>  	int ret;
> @@ -478,8 +478,10 @@ static void msgdma_reset(struct msgdma_device *mdev)
>  	ret = readl_poll_timeout(mdev->csr + MSGDMA_CSR_STATUS, val,
>  				 (val & MSGDMA_CSR_STAT_RESETTING) == 0,
>  				 1, 10000);
> -	if (ret)
> +	if (ret) {
>  		dev_err(mdev->dev, "DMA channel did not reset\n");
> +		return ret;
> +	}
>
>  	/* Clear all status bits */
>  	iowrite32(MSGDMA_CSR_STAT_MASK, mdev->csr + MSGDMA_CSR_STATUS);
> @@ -489,6 +491,7 @@ static void msgdma_reset(struct msgdma_device *mdev)
>  		  MSGDMA_CSR_CTL_GLOBAL_INTR, mdev->csr + MSGDMA_CSR_CONTROL);
>
>  	mdev->idle = true;
> +	return 0;
>  };
>
>  static void msgdma_copy_one(struct msgdma_device *mdev,
> @@ -896,7 +899,9 @@ static int msgdma_probe(struct platform_device *pdev)
>  		goto fail;
>  	}
>
> -	msgdma_reset(mdev);
> +	ret = msgdma_reset(mdev);
> +	if (ret)
> +		goto fail;
>
>  	ret = dma_async_device_register(dma_dev);
>  	if (ret)
> --
> 2.50.1 (Apple Git-155)
>