linux-kernel - Re: [PATCH v2 2/5] dma: mcf-edma: Add per-channel IRQ naming for debugging

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Message-ID: <aScnArV/22L5VmxP@lizhi-Precision-Tower-5810>
Date: Wed, 26 Nov 2025 11:12:50 -0500
From: Frank Li <Frank.li@....com>
To: jeanmichel.hautbois@...eli.org
Cc: Vinod Koul <vkoul@...nel.org>, Angelo Dureghello <angelo@...am.it>,
	Greg Ungerer <gerg@...ux-m68k.org>, imx@...ts.linux.dev,
	dmaengine@...r.kernel.org, linux-m68k@...ts.linux-m68k.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/5] dma: mcf-edma: Add per-channel IRQ naming for
 debugging

On Wed, Nov 26, 2025 at 09:36:03AM +0100, Jean-Michel Hautbois via B4 Relay wrote:
> From: Jean-Michel Hautbois <jeanmichel.hautbois@...eli.org>
>
> Add dynamic per-channel IRQ naming to make DMA interrupt identification
> easier in /proc/interrupts and debugging tools.
>
> Instead of all channels showing "eDMA", they now show:
> - "eDMA-0" through "eDMA-15" for channels 0-15
> - "eDMA-16" through "eDMA-55" for channels 16-55
> - "eDMA-tx-56" for the shared channel 56-63 interrupt
> - "eDMA-err" for the error interrupt
>
> This aids debugging DMA issues by making it clear which channel's
> interrupt is being serviced.
>
> Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois@...eli.org>
> ---
>  drivers/dma/mcf-edma-main.c | 26 ++++++++++++++++++--------
>  1 file changed, 18 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/dma/mcf-edma-main.c b/drivers/dma/mcf-edma-main.c
> index f95114829d80..6a7d88895501 100644
> --- a/drivers/dma/mcf-edma-main.c
> +++ b/drivers/dma/mcf-edma-main.c
> @@ -81,8 +81,14 @@ static int mcf_edma_irq_init(struct platform_device *pdev,
>  	if (!res)
>  		return -1;
>
> -	for (ret = 0, i = res->start; i <= res->end; ++i)
> -		ret |= request_irq(i, mcf_edma_tx_handler, 0, "eDMA", mcf_edma);
> +	for (ret = 0, i = res->start; i <= res->end; ++i) {
> +		char *irq_name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
> +						"eDMA-%d", (int)(i - res->start));
> +		if (!irq_name)
> +			return -ENOMEM;
> +
> +		ret |= request_irq(i, mcf_edma_tx_handler, 0, irq_name, mcf_edma);
> +	}
>  	if (ret)
>  		return ret;

The existing code have problem, it should use devm_request_irq(). if one
irq request failure, return here,  requested irq will not free.

You'd better add patch before this one to change to use devm_request_irq()

Frank

>
> @@ -91,23 +97,27 @@ static int mcf_edma_irq_init(struct platform_device *pdev,
>  	if (!res)
>  		return -1;
>
> -	for (ret = 0, i = res->start; i <= res->end; ++i)
> -		ret |= request_irq(i, mcf_edma_tx_handler, 0, "eDMA", mcf_edma);
> +	for (ret = 0, i = res->start; i <= res->end; ++i) {
> +		char *irq_name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
> +						"eDMA-%d", (int)(16 + i - res->start));
> +		if (!irq_name)
> +			return -ENOMEM;
> +
> +		ret |= request_irq(i, mcf_edma_tx_handler, 0, irq_name, mcf_edma);
> +	}
>  	if (ret)
>  		return ret;
>
>  	ret = platform_get_irq_byname(pdev, "edma-tx-56-63");
>  	if (ret != -ENXIO) {
> -		ret = request_irq(ret, mcf_edma_tx_handler,
> -				  0, "eDMA", mcf_edma);
> +		ret = request_irq(ret, mcf_edma_tx_handler, 0, "eDMA-tx-56", mcf_edma);
>  		if (ret)
>  			return ret;
>  	}
>
>  	ret = platform_get_irq_byname(pdev, "edma-err");
>  	if (ret != -ENXIO) {
> -		ret = request_irq(ret, mcf_edma_err_handler,
> -				  0, "eDMA", mcf_edma);
> +		ret = request_irq(ret, mcf_edma_err_handler, 0, "eDMA-err", mcf_edma);
>  		if (ret)
>  			return ret;
>  	}
>
> --
> 2.39.5
>
>