Re: [PATCH v6 3/3] dts: s32g: Add GPR syscon region

Jared Kangas
2026-04-17T21:36:32Z

Hi Dan,

On Fri, Jan 30, 2026 at 04:19:52PM +0300, Dan Carpenter wrote:
> Add the GPR syscon region for the s32 chipset.
>
> Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
> ---
>
> [snip]
>
> diff --git a/arch/arm64/boot/dts/freescale/s32g3.dtsi b/arch/arm64/boot/dts/freescale/s32g3.dtsi
> index e314f3c7d61d..be03db737384 100644
> --- a/arch/arm64/boot/dts/freescale/s32g3.dtsi
> +++ b/arch/arm64/boot/dts/freescale/s32g3.dtsi
> @@ -383,6 +383,11 @@ usdhc0-200mhz-grp4 {
> };
> };
>
> + gpr: syscon@4007c000 {
> + compatible = "nxp,s32g3-gpr", "syscon";
> + reg = <0x4007c000 0x3000>;
> + };
> +
> ocotp: nvmem@400a4000 {
> compatible = "nxp,s32g3-ocotp", "nxp,s32g2-ocotp";
> reg = <0x400a4000 0x400>;
> @@ -808,6 +813,7 @@ gmac0: ethernet@4033c000 {
> compatible = "nxp,s32g2-dwmac";
> reg = <0x4033c000 0x2000>, /* gmac IP */
> <0x4007c004 0x4>; /* GMAC_0_CTRL_STS */
> + nxp,phy-sel = <&gpr 0x4>;
> interrupt-parent = <&gic>;
> interrupts = <GIC_SPI 57 IRQ_TYPE_LEVEL_HIGH>;
> interrupt-names = "macirq";

I gave this a test on an S32G-VNP-RDB3 and didn't see any issues on the
dwmac-s32 side, but this appears to trigger a panic when reading the new
debugfs regmap/*/registers file for the syscon node:

# grep 4007c000 /proc/vmallocinfo
0xffff800083da8000-0xffff800083dac000 16384 ioremap_prot+0x74/0xe0 phys=0x000000004007c000 ioremap
# cat /sys/kernel/debug/regmap/dummy-syscon@0x000000004007c000/registers
Internal error: synchronous external abort: 0000000096000210 [#1] SMP
[...]
CPU: 0 UID: 0 PID: 4344 Comm: cat Tainted: G M E X ------ --- 6.12.0+ #226 PREEMPT_RT
Tainted: [M]=MACHINE_CHECK, [E]=UNSIGNED_MODULE, [X]=AUX
[...]
pc : regmap_mmio_read32le+0x44/0xa0
lr : regmap_mmio_read32le+0x44/0xa0
[...]
x23: ffff00080c080000 x22: ffff000802ac4c00 x21: ffff800087b13c9c
x20: ffff800080a46494 x19: ffff800083da810c x18: 0000000000000004
[...]
x5 : ffff800080a46448 x4 : ffff800083da8000 x3 : ffff800080a46494
x2 : ffff800080a47230 x1 : ffff800083da810c x0 : 0000000000000020
Call trace:
regmap_mmio_read32le+0x44/0xa0 (P)
regmap_mmio_read+0x4c/0x80
[...]
Code: 52800400 8b214093 aa1303e1 97f4caf0 (b9400275)
---[ end trace 0000000000000000 ]---
Kernel panic - not syncing: synchronous external abort: Fatal exception

Running this through decodecode gives:

All code
========
0: 52800400 mov w0, #0x20 // #32
4: 8b214093 add x19, x4, w1, uxtw
8: aa1303e1 mov x1, x19
c: 97f4caf0 bl 0xffffffffffd32bcc
10:* b9400275 ldr w21, [x19] <-- trapping instruction

Code starting with the faulting instruction
===========================================
0: b9400275 ldr w21, [x19]

x19's offset from the base address in /proc/vmallocinfo is 0x10c, which
points to a bad read at physical address 0x4007c10c; I also confirmed
that the preceding memory reads back without issues:

# head -c 990 /sys/kernel/debug/regmap/dummy-syscon@0x000000004007c000/registers | tail -1
0104: 00000000
# head -c 1005 /sys/kernel/debug/regmap/dummy-syscon@0x000000004007c000/registers | tail -1
0108: 00000000
# head -c 1020 /sys/kernel/debug/regmap/dummy-syscon@0x000000004007c000/registers | tail -1
<panic>

Best,
Jared