linux-kernel - Re: [PATCH 2/3] dma: arm-dma350: add support for shared interrupt mode

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Message-ID: <eb9eae64-f414-4b04-9a10-4dd8a9088e96@kernel.org>
Date: Mon, 17 Nov 2025 07:13:34 +0100
From: Krzysztof Kozlowski <krzk@...nel.org>
To: Jun Guo <jun.guo@...tech.com>, peter.chen@...tech.com,
 fugang.duan@...tech.com, robh@...nel.org, krzk+dt@...nel.org,
 conor+dt@...nel.org, vkoul@...nel.org, ychuang3@...oton.com,
 schung@...oton.com, robin.murphy@....com
Cc: dmaengine@...r.kernel.org, devicetree@...r.kernel.org,
 linux-kernel@...r.kernel.org, cix-kernel-upstream@...tech.com,
 linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH 2/3] dma: arm-dma350: add support for shared interrupt
 mode

On 17/11/2025 02:59, Jun Guo wrote:
> - The arm dma350 controller's hardware implementation varies: some

That's not a list. Look at git history to learn how to write expected
commit messages.

>  designs dedicate a separate interrupt line for each channel, while
>  others have all channels sharing a single interrupt.This patch adds
>  support for the hardware design where all DMA channels share a
>  single interrupt.
> 
> Signed-off-by: Jun Guo <jun.guo@...tech.com>
> ---
>  drivers/dma/ar



> @@ -526,7 +593,7 @@ static void d350_free_chan_resources(struct dma_chan *chan)
>  static int d350_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
> -	struct d350 *dmac;
> +	struct d350 *dmac = NULL;
>  	void __iomem *base;
>  	u32 reg;
>  	int ret, nchan, dw, aw, r, p;
> @@ -556,6 +623,7 @@ static int d350_probe(struct platform_device *pdev)
>  		return -ENOMEM;
>  
>  	dmac->nchan = nchan;
> +	dmac->base = base;
>  
>  	reg = readl_relaxed(base + DMAINFO + DMA_BUILDCFG1);
>  	dmac->nreq = FIELD_GET(DMA_CFG_NUM_TRIGGER_IN, reg);
> @@ -582,6 +650,26 @@ static int d350_probe(struct platform_device *pdev)
>  	dmac->dma.device_issue_pending = d350_issue_pending;
>  	INIT_LIST_HEAD(&dmac->dma.channels);
>  
> +	/* Cix Sky1 has a common host IRQ for all its channels. */
> +	if (of_device_is_compatible(pdev->dev.of_node, "cix,sky1-dma-350")) {

No, see further

> +		int host_irq = platform_get_irq(pdev, 0);
> +
> +		if (host_irq < 0)
> +			return dev_err_probe(dev, host_irq,
> +					     "Failed to get IRQ\n");
> +
> +		ret = devm_request_irq(&pdev->dev, host_irq, d350_global_irq,
> +				       IRQF_SHARED, DRIVER_NAME, dmac);
> +		if (ret)
> +			return dev_err_probe(
> +				dev, ret,
> +				"Failed to request the combined IRQ %d\n",
> +				host_irq);
> +
> +		/* Combined Non-Secure Channel Interrupt Enable */
> +		writel_relaxed(INTREN_ANYCHINTR_EN, dmac->base + DMANSECCTRL);
> +	}
> +
>  	/* Would be nice to have per-channel caps for this... */
>  	memset = true;
>  	for (int i = 0; i < nchan; i++) {
> @@ -595,10 +683,16 @@ static int d350_probe(struct platform_device *pdev)
>  			dev_warn(dev, "No command link support on channel %d\n", i);
>  			continue;
>  		}
> -		dch->irq = platform_get_irq(pdev, i);
> -		if (dch->irq < 0)
> -			return dev_err_probe(dev, dch->irq,
> -					     "Failed to get IRQ for channel %d\n", i);
> +
> +		if (!of_device_is_compatible(pdev->dev.of_node,
> +					     "cix,sky1-dma-350")) {

No, use driver match data for that. Sprinkling compatibles everywhere
does not scale.

Also, this is in contrary with the binding, which did not say your
device has no interrupts.


Best regards,
Krzysztof