Re: [PATCH v7 09/24] dmaengine: ste_dma40: Init hardware before registration

[Frank Li <Frank.li@oss.nxp.com>]

On Sun, Sep 27, 2026 at 11:03:22AM +0200, Linus Walleij wrote:
> d40_probe() enables the interrupt handler and registers DMAengine devices
> before calling d40_hw_init(). An interrupt pending from the bootloader can
> therefore reach the handler while the hardware interrupt state is not
> initialized and channel lookup entries are empty. The handler deliberately
> does not acknowledge an interrupt for an unknown channel, so a level IRQ
> can retrigger continuously.
>
> Initialize the hardware and set the DMA segment limit before requesting
> the IRQ or registering DMAengine devices. d40_hw_init() clears pending
> logical and physical interrupt status, so request_irq() can enable the
> line normally after the hardware state is initialized.
>
> This ensures that the handler and clients only observe initialized
> hardware.
>
> Fixes: 8d318a50b3d7 ("DMAENGINE: Support for ST-Ericssons DMA40 block v3")
> Reported-by: sashiko-bot@kernel.org
> Closes: https://lore.kernel.org/dmaengine/20260819225215.5EA2F1F000E9@smtp.kernel.org/
> Assisted-by: LLM
> Signed-off-by: Linus Walleij <linusw@kernel.org>
> ---

Reviewed-by: Frank Li <Frank.Li@nxp.com>

>  drivers/dma/ste_dma40.c | 9 ++++-----
>  1 file changed, 4 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/dma/ste_dma40.c b/drivers/dma/ste_dma40.c
> index 86efe2149be9..3bf89b057ccf 100644
> --- a/drivers/dma/ste_dma40.c
> +++ b/drivers/dma/ste_dma40.c
> @@ -3835,20 +3835,19 @@ static int __init d40_probe(struct platform_device *pdev)
>  	}
>  	pm_runtime_use_autosuspend(base->dev);
>
> +	dma_set_max_seg_size(base->dev, STEDMA40_MAX_SEG_SIZE);
> +
> +	d40_hw_init(base);
> +
>  	ret = request_irq(base->irq, d40_handle_interrupt, 0, D40_NAME, base);
>  	if (ret) {
>  		d40_err(dev, "No IRQ defined\n");
>  		goto destroy_cache;
>  	}
> -
>  	ret = d40_dmaengine_init(base, num_reserved_chans);
>  	if (ret)
>  		goto destroy_cache;
>
> -	dma_set_max_seg_size(base->dev, STEDMA40_MAX_SEG_SIZE);
> -
> -	d40_hw_init(base);
> -
>  	ret = of_dma_controller_register(np, d40_xlate, NULL);
>  	if (ret) {
>  		dev_err(dev,
>
> --
> 2.55.0
>