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

[Jared Kangas <jkangas@redhat.com>]

Fixing Dan's address based on mailmap update, sorry for the noise.

On Fri, Apr 17, 2026 at 02:36:25PM -0700, Jared Kangas wrote:
> 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
>