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 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 <mbrugger@suse.com>
Signed-off-by: Jan Petrous (OSS) <jan.petrous@oss.nxp.com>
---
 drivers/net/ethernet/stmicro/stmmac/dwmac-s32.c | 12 +++++++++++-
 1 file changed, 11 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..37a5b7b46973 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 +149,16 @@ 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)) {
+		plat->flags |= STMMAC_FLAG_MULTI_MSI_EN;
+		dev_info(dev, "Multi-IRQ mode (per queue IRQs) selected\n");
+	} else {
+		dev_info(dev, "MAC IRQ mode selected\n");
+	}
+
 	plat->rx_fifo_size = 20480;
 	plat->tx_fifo_size = 20480;
 

-- 
2.47.0

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---
stmmac: s32: enable support for Multi-IRQ mode

Enables Multi-IRQ mode for the S32 GMAC driver when per-queue IRQs
are present and more than one RX queue is configured.

> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-s32.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-s32.c
> index 5a485ee98fa7..37a5b7b46973 100644

[ ... ]

> @@ -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 */
                                                   ^^^^^^^^^^

This isn't a bug, but "symetrical" should be "symmetrical".