Subject: Re: [PATCH v7 2/5] net: stmmac: platform: read channels irq

From: "Russell King (Oracle)" <[email-masked]>
Date: Thu, 26 Feb 2026 19:10:22 +0000

On Thu, Feb 26, 2026 at 09:54:07AM +0100, Jan Petrous via B4 Relay wrote:
> From: "Jan Petrous (OSS)" <[email-masked]>
> 
> Read IRQ resources for all rx/tx channels, to allow Multi-IRQ mode
> for platform glue drivers.
> 
> Reviewed-by: Matthias Brugger <[email-masked]>
> Signed-off-by: Jan Petrous (OSS) <[email-masked]>
> ---
>  .../net/ethernet/stmicro/stmmac/stmmac_platform.c  | 46 +++++++++++++++++++++-
>  1 file changed, 45 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
> index 5c9fd91a1db9..93bd915ab6eb 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
> @@ -697,9 +697,40 @@ struct clk *stmmac_pltfr_find_clk(struct plat_stmmacenet_data *plat_dat,
>  }
>  EXPORT_SYMBOL_GPL(stmmac_pltfr_find_clk);
>  
> +static int stmmac_pltfr_get_queue_irqs(struct platform_device *pdev,
> +				       struct stmmac_resources *stmmac_res,
> +				       bool tx)
> +{
> +	int *irqs = tx ? &stmmac_res->tx_irq[0] : &stmmac_res->rx_irq[0];
> +	char name[16];
> +	int i;
> +
> +	/* RX channels irq */
> +	STMMAC_FOREACH_MTL_QUEUE(i, MTL_MAX_RX_QUEUES) {

You've missed that there are two separate definitions for tx and rx
queues - while they are currently the same number, code shouldn't
make that assumption.

> +		scnprintf(name, sizeof(name), "%cx-queue-%d",
> +			  tx ? 't' : 'r', i);

I'm not happy with this method of combining the two loops.

Maybe instead:

static int stmmac_pltfr_get_irq_array(struct platform_device *pdev,
				      const char *fmt, int *irqs,
				      size_t num)
{
	char name[16];
	size_t i;

	for (i = 0; i < num; i++) {
		if (snprintf(name, sizeof(name), fmt, i) >= sizeof(name))
			return -EINVAL;

		irqs[i] = platform_get_irq_byname_optional(pdev, name);
		if (irqs[i] == -EPROBE_DEFER) {
			return irqs[i];
		} else if (irqs[i] <= 0) {
			dev_dbg(&pdev->dev, "IRQ %s not found\n", name);

			irqs[i] = 0;
			break;
		}
	}

	return 0;
}

which has the advantage that it becomes a generic helper for getting an
any array of IRQs.

>  int stmmac_get_platform_resources(struct platform_device *pdev,
>  				  struct stmmac_resources *stmmac_res)
>  {
> +	int ret;
> +
>  	memset(stmmac_res, 0, sizeof(*stmmac_res));
>  
>  	/* Get IRQ information early to have an ability to ask for deferred
> @@ -735,7 +766,20 @@ int stmmac_get_platform_resources(struct platform_device *pdev,
>  
>  	stmmac_res->addr = devm_platform_ioremap_resource(pdev, 0);
>  
> -	return PTR_ERR_OR_ZERO(stmmac_res->addr);
> +	if (IS_ERR(stmmac_res->addr))
> +		return PTR_ERR(stmmac_res->addr);
> +
> +	/* TX channels irq */
> +	ret = stmmac_pltfr_get_queue_irqs(pdev, stmmac_res, true);
> +	if (ret)
> +		return ret;
> +
> +	/* RX channels irq */
> +	ret = stmmac_pltfr_get_queue_irqs(pdev, stmmac_res, false);
> +	if (ret)
> +		return ret;

These then become:

	ret = stmmac_pltfr_get_irq_array(pdev, "tx-queue-%d", 
					 stmmac_res->tx_irq,
					 MTL_MAX_TX_QUEUES);
	if (ret)
		return ret;

	ret = stmmac_pltfr_get_irq_array(pdev, "rx-queue-%d", 
					 stmmac_res->rx_irq,
					 MTL_MAX_RX_QUEUES);
	if (ret)
		return ret;

This has the advantage that one can grep for rx-queue to find it,
and we also use the correct limit for each queue type.

-- 
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