Subject: Re: [PATCH net-next v12 4/4] stmmac: s32: enable support for Multi-IRQ mode

From: "Russell King (Oracle)" <[email-masked]>
Date: Fri, 13 Mar 2026 09:32:22 +0000

On Fri, Mar 13, 2026 at 08:13:35AM +0100, Jan Petrous via B4 Relay wrote:
> From: "Jan Petrous (OSS)" <[email-masked]>
> 
> Based on previous changes in platform driver, the vendor
> glue driver can enable Multi-IRQ mode, if needed.
> 
> To get enabled Multi-IRQ mode for dwmac-s32, 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 switches to Multi-IRQ mode,
> using per-queue IRQs for rx/tx data pathr:
> 
> [    1.387045] s32-dwmac 4033c000.ethernet: Multi-IRQ mode (per queue IRQs) 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.
> 
> Reviewed-by: Matthias Brugger <[email-masked]>

Reviewed-by: Russell King (Oracle) <[email-masked]>

Thanks!

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