Re: [PATCH RFC v2 4/4] stmmac: s32: enable support for Multi-IRQ mode

[Matthias Brugger <mbrugger@suse.com>]

On 21/01/2026 15:23, Jan Petrous via B4 Relay wrote:
> From: "Jan Petrous (OSS)" <jan.petrous@oss.nxp.com>
> 
> To get enabled Multi-IRQ mode, the driver checks:
> 
>    1) property of 'snps,mtl-xx-config' subnode
>       defines 'snps,xx-queues-to-use' bigger then one, ie:
> 
>       ethernet@4033c000 {
>           compatible = "nxp,s32g2-dwmac";
>           ...
>           snps,mtl-rx-config = <&mtl_rx_setup>;
>           ...
> 
>           mtl_rx_setup: rx-queues-config {
>               snps,rx-queues-to-use = <2>;
>           };
> 
>    2) queue based IRQs are set, ie:
> 
>       ethernet@4033c000 {
>           compatible = "nxp,s32g2-dwmac";
>           ...
>           interrupts = <GIC_SPI 57 IRQ_TYPE_LEVEL_HIGH>,
>                        /* CHN 0: tx, rx */
>                        <GIC_SPI 58 IRQ_TYPE_LEVEL_HIGH>,
>                        <GIC_SPI 59 IRQ_TYPE_LEVEL_HIGH>,
>                        /* CHN 1: tx, rx */
>                        <GIC_SPI 60 IRQ_TYPE_LEVEL_HIGH>,
>                        <GIC_SPI 61 IRQ_TYPE_LEVEL_HIGH>;
>           interrupt-names = "macirq",
>                             "tx-queue-0", "rx-queue-0",
>                             "tx-queue-1", "rx-queue-1";
> 
> If those prerequisites are met, the driver switch to Multi-IRQ mode,
> using per-queue IRQs for rx/tx data pathr:
> 
> [    1.387045] s32-dwmac 4033c000.ethernet: Multi-IRQ mode (per queue IRQ) selected
> 
> Now the driver owns all queues IRQs:
> 
> root@s32g399aevb3:~# grep eth /proc/interrupts
>   29:    0    0    0    0    0    0    0    0    GICv3  89 Level   eth0:mac
>   30:    0    0    0    0    0    0    0    0    GICv3  91 Level   eth0:rx-0
>   31:    0    0    0    0    0    0    0    0    GICv3  93 Level   eth0:rx-1
>   32:    0    0    0    0    0    0    0    0    GICv3  95 Level   eth0:rx-2
>   33:    0    0    0    0    0    0    0    0    GICv3  97 Level   eth0:rx-3
>   34:    0    0    0    0    0    0    0    0    GICv3  99 Level   eth0:rx-4
>   35:    0    0    0    0    0    0    0    0    GICv3  90 Level   eth0:tx-0
>   36:    0    0    0    0    0    0    0    0    GICv3  92 Level   eth0:tx-1
>   37:    0    0    0    0    0    0    0    0    GICv3  94 Level   eth0:tx-2
>   38:    0    0    0    0    0    0    0    0    GICv3  96 Level   eth0:tx-3
>   39:    0    0    0    0    0    0    0    0    GICv3  98 Level   eth0:tx-4
> 
> Otherwise, if one of the prerequisite don't met, the driver
> continue with MAC IRQ mode:
> 
> [    1.387045] s32-dwmac 4033c000.ethernet: MAC IRQ mode selected
> 
> And only MAC IRQ will be attached:
> 
> root@s32g399aevb3:~# grep eth /proc/interrupts
>   29:    0    0    0    0    0    0    0    0    GICv3  89 Level   eth0:mac
> 
> What represents the original MAC IRQ mode and is fully backward
> compatible.
> 
> Signed-off-by: Jan Petrous (OSS) <jan.petrous@oss.nxp.com>

Reviewed-by: Matthias Brugger <mbrugger@suse.com>

> ---
>   drivers/net/ethernet/stmicro/stmmac/dwmac-s32.c | 13 ++++++++++++-
>   1 file changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-s32.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-s32.c
> index 5a485ee98fa7..823700219534 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/dwmac-s32.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-s32.c
> @@ -2,7 +2,7 @@
>   /*
>    * NXP S32G/R GMAC glue layer
>    *
> - * Copyright 2019-2024 NXP
> + * Copyright 2019-2026 NXP
>    *
>    */
>   
> @@ -149,6 +149,17 @@ 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)) {
> +		plat->flags |= STMMAC_FLAG_MULTI_MSI_EN;
> +		dev_info(dev, "Multi-IRQ mode (per queue IRQ) selected\n");
> +	} else {
> +		dev_info(dev, "MAC IRQ mode selected\n");
> +	}
> +
> +	plat->flags |= STMMAC_FLAG_MULTI_MSI_EN;
>   	plat->rx_fifo_size = 20480;
>   	plat->tx_fifo_size = 20480;
>   
>