Re: [PATCH] spi: mediatek: Enable irq before the spi registration

[Daniel Golle]

On Sun, Dec 25, 2022 at 09:37:12AM +0100, Ricardo Ribalda wrote:
> If the irq is enabled after the spi si registered, there can be a race
> with the initialization of the devices on the spi bus.
> 
> Eg:
> mtk-spi 1100a000.spi: spi-mem transfer timeout
> spi-nor: probe of spi0.0 failed with error -110
> Unable to handle kernel NULL pointer dereference at virtual address
> 0000000000000010
> ...
> Call trace:
>  mtk_spi_can_dma+0x0/0x2c
> 
> Fixes: c6f7874687f7 ("spi: mediatek: Enable irq when pdata is ready")
> Reported-by: Daniel Golle <daniel@xxxxxxxxxxxxxx>
> Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
> ---
> spi: mediatek: Fix init order (again)
> 
> Hi Mark
> 
> Here is a fixup of the previous patch. Daniel, can you confirm that it
> works on your hardware? 

Yes, this fixes the issue and SPI now works fine on MT7986 with the
patch applied.

Tested-by: Daniel Golle <daniel@xxxxxxxxxxxxxx>

> 
> Thanks and sorry for annoyance. 
> 
> To: Mark Brown <broonie@xxxxxxxxxx>
> To: Matthias Brugger <matthias.bgg@xxxxxxxxx>
> To: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
> Cc: linux-spi@xxxxxxxxxxxxxxx
> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> Cc: linux-mediatek@xxxxxxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Cc: Daniel Golle <daniel@xxxxxxxxxxxxxx>
> ---
>  drivers/spi/spi-mt65xx.c | 12 +++++-------
>  1 file changed, 5 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/spi/spi-mt65xx.c b/drivers/spi/spi-mt65xx.c
> index 6de8360e5c2a..9eab6c20dbc5 100644
> --- a/drivers/spi/spi-mt65xx.c
> +++ b/drivers/spi/spi-mt65xx.c
> @@ -1253,6 +1253,11 @@ static int mtk_spi_probe(struct platform_device *pdev)
>  		dev_notice(dev, "SPI dma_set_mask(%d) failed, ret:%d\n",
>  			   addr_bits, ret);
>  
> +	ret = devm_request_irq(dev, irq, mtk_spi_interrupt,
> +			       IRQF_TRIGGER_NONE, dev_name(dev), master);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "failed to register irq\n");
> +
>  	pm_runtime_enable(dev);
>  
>  	ret = devm_spi_register_master(dev, master);
> @@ -1261,13 +1266,6 @@ static int mtk_spi_probe(struct platform_device *pdev)
>  		return dev_err_probe(dev, ret, "failed to register master\n");
>  	}
>  
> -	ret = devm_request_irq(dev, irq, mtk_spi_interrupt,
> -			       IRQF_TRIGGER_NONE, dev_name(dev), master);
> -	if (ret) {
> -		pm_runtime_disable(dev);
> -		return dev_err_probe(dev, ret, "failed to register irq\n");
> -	}
> -
>  	return 0;
>  }
>  
> 
> ---
> base-commit: 45b3cd900bf8d1a3cd7cf48361df8c09ae5b4009
> change-id: 20221225-mtk-spi-fixes-99c863a6fdf1
> 
> Best regards,
> -- 
> Ricardo Ribalda <ribalda@xxxxxxxxxxxx>