Re: [PATCH v5 4/4] dmaengine: zynqmp_dma: Add per-channel reset support

[Pandey, Radhey Shyam]

On 11/6/2026 3:40 PM, Golla Nagendra wrote:
> Versal Gen2 and Versal Net expose a dedicated reset line per ZDMA
> channel. Trigger a reset pulse during probe using device_reset().
>
> For Versal Net and Versal Gen2, reset is a required DT property, so
> probe returns an error if the reset property is missing. For legacy
> SoCs, the reset path is skipped.
>
> Signed-off-by: Golla Nagendra <nagendra.golla@xxxxxxx>

Reviewed-by: Radhey Shyam Pandey <radhey.shyam.pandey@xxxxxxx>
Thanks!

> ---
>   drivers/dma/xilinx/zynqmp_dma.c | 10 +++++++++-
>   1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/dma/xilinx/zynqmp_dma.c b/drivers/dma/xilinx/zynqmp_dma.c
> index cb0eb13f9b05..12696fa44c66 100644
> --- a/drivers/dma/xilinx/zynqmp_dma.c
> +++ b/drivers/dma/xilinx/zynqmp_dma.c
> @@ -19,6 +19,7 @@
>   #include <linux/clk.h>
>   #include <linux/io-64-nonatomic-lo-hi.h>
>   #include <linux/pm_runtime.h>
> +#include <linux/reset.h>
>   
>   #include "../dmaengine.h"
>   
> @@ -937,6 +938,14 @@ static int zynqmp_dma_chan_probe(struct zynqmp_dma_device *zdev,
>   	if (IS_ERR(chan->regs))
>   		return PTR_ERR(chan->regs);
>   
> +	match_data = of_device_get_match_data(&pdev->dev);
> +	if (match_data && match_data->has_reset) {
> +		err = device_reset(&pdev->dev);
> +		if (err)
> +			return dev_err_probe(&pdev->dev, err,
> +					     "failed to reset channel\n");
> +	}
> +
>   	chan->bus_width = ZYNQMP_DMA_BUS_WIDTH_64;
>   	chan->dst_burst_len = ZYNQMP_DMA_MAX_DST_BURST_LEN;
>   	chan->src_burst_len = ZYNQMP_DMA_MAX_SRC_BURST_LEN;
> @@ -952,7 +961,6 @@ static int zynqmp_dma_chan_probe(struct zynqmp_dma_device *zdev,
>   		return -EINVAL;
>   	}
>   
> -	match_data = of_device_get_match_data(&pdev->dev);
>   	if (match_data)
>   		chan->irq_offset = match_data->offset;
>