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.
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..342091045714 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 IRQ) selected\n");
+ } else {
+ dev_info(dev, "MAC IRQ mode selected\n");
+ }
+
plat->rx_fifo_size = 20480;
plat->tx_fifo_size = 20480;
--
2.47.0This 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.
Since 0 >= 0 evaluates to true, this condition will enable Multi-IRQ
mode even when no per-queue IRQs are available. The commit message states
that "queue based IRQs are set" is a prerequisite, but the current check
does not properly verify this.
> + plat->flags |= STMMAC_FLAG_MULTI_MSI_EN;
> + dev_info(dev, "Multi-IRQ mode (per queue IRQ) selected\n");
[ ... ]
--
pw-bot: cr
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
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