Re: [PATCH] dmaengine: sun6i: Fix physical channel index in interrupt handler

[Frank Li]

On Mon, Jul 06, 2026 at 02:41:23PM +0800, Hongling Zeng wrote:
> The interrupt handler iterates over register banks in the outer loop
> (i = 0, 1, ...), where each bank covers DMA_IRQ_CHAN_NR (8) channels.
> However, the physical channel lookup uses only the inner loop index j,
> ignoring the bank offset i.
>
> This means for SoCs with more than 8 DMA channels, interrupts from
> physical channels 8 and above are incorrectly routed to physical
> channels 0-7. This can falsely complete descriptors for unrelated
> channels, potentially causing silent memory corruption.
>
> Fix by using the absolute channel index (i * DMA_IRQ_CHAN_NR + j).
>
> Fixes: 555859308723 ("dmaengine: sun6i: Add driver for the Allwinner A31 DMA controller")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Hongling Zeng <zenghongling@xxxxxxxxxx>
> ---

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

>  drivers/dma/sun6i-dma.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c
> index a6487971ad09..fcc88a74d821 100644
> --- a/drivers/dma/sun6i-dma.c
> +++ b/drivers/dma/sun6i-dma.c
> @@ -559,7 +559,7 @@ static irqreturn_t sun6i_dma_interrupt(int irq, void *dev_id)
>  		writel(status, sdev->base + DMA_IRQ_STAT(i));
>
>  		for (j = 0; (j < DMA_IRQ_CHAN_NR) && status; j++) {
> -			pchan = sdev->pchans + j;
> +			pchan = sdev->pchans + i * DMA_IRQ_CHAN_NR + j;
>  			vchan = pchan->vchan;
>  			if (vchan && (status & vchan->irq_type)) {
>  				if (vchan->cyclic) {
> --
> 2.25.1
>