[v3,4/4] stmmac: s32: enable support for Multi-IRQ mode

[Jan Petrous]

On Sun, Jan 25, 2026 at 02:14:05PM -0800, Jakub Kicinski wrote:
> This is an AI-generated review of your patch. The human sending this
> email has considered the AI review valid, or at least plausible.
> 
> For local reproduction steps see https://netdev-ai.bots.linux.dev/ai-local.html
> ---
> stmmac: s32: enable support for Multi-IRQ mode
> 
> This patch enables Multi-IRQ mode for the S32 DWMAC driver when both
> multi-queue and per-queue IRQs are configured. The driver now selects
> between Multi-IRQ and MAC IRQ modes based on device tree configuration.
> 
> > diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-s32.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-s32.c
> > index 5a485ee98fa7..342091045714 100644
> > --- a/drivers/net/ethernet/stmicro/stmmac/dwmac-s32.c
> > +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-s32.c
> 
> [ ... ]
> 
> > @@ -149,6 +149,16 @@ static int s32_dwmac_probe(struct platform_device *pdev)
> >  	plat->core_type = DWMAC_CORE_GMAC4;
> >  	plat->pmt = 1;
> >  	plat->flags |= STMMAC_FLAG_SPH_DISABLE;
> > +
> > +	/* Check for multi-IRQ config. Assumption: symetrical rx/tx queues */
> > +	if (plat->rx_queues_to_use > 1 &&
> > +	    (res.rx_irq[0] >= 0 || res.tx_irq[0] >= 0)) {
>                         ^^^^            ^^^^
> 
> Should these checks be "> 0" instead of ">= 0"?
> 
> stmmac_get_platform_resources() initializes the res structure with
> memset(0), then only writes positive IRQ values when per-queue IRQs are
> found in the device tree. If no "rx-queue-0" or "tx-queue-0" interrupt
> names are defined, rx_irq[0] and tx_irq[0] remain 0 from the memset.

The AI is wrong on this statesment. The loop reading IRQs from DT
in stmmac_get_platform_resources() returns also negative value
for missed queue IRQ line. And this is used as flag if multi-IRQ
can be enabled or not.

But I must agree that the comparition shall not include 0 as valid
value for IRQ, so I will fix it in v4.

Thanks.
/Jan