Re: Raspberry Pi 4 support on 32 bit earmv7hf GENERIC kernel

On 25/03/2026 16:36, Izumi Tsutsui wrote:
> Updated diffs:
>   https://github.com/tsutsui/netbsd-src/compare/trunk...rpi4-earmv7hf-re=
v2
>=20
> I wrote:
>>>>> Perhaps the DTS need patching with
>>>>>
>>>>> bcm2711.dtsi:           enable-method =3D "brcm,bcm2836-smp"; // for=
 ARM 32-bit
>>>>>
>>>>> s/brcm,bcm2836-smp/brcm,bcm2711-smp/
>>>>
>>>> I have no idea if we should patch DTS for maintainability.
>>>
>>> Well there is a way to fix upstream DTS (it can and does have bugs) wi=
thout
>>> changing sys/external/gpl2/dts/dist
>>>
>>> See sys/arch/arm/dts
>>
>> Well, it's a bit hard to see how local changes should be applied,
>> but I'll check them later. (Any documentation?)
>=20
> https://github.com/tsutsui/netbsd-src/commit/8af7f6d20a4490e1205a63684d6=
970790737dace
>=20
> ---
> bcm2711: patch cpus "enable-method" in dts and use it on initialization
>=20
> The upstream bcm2711.dtsi returns "brcm,bcm2836-smp" as "enable-method" =
on
> /cpus node but bcm2711 requires different addresses from bcm2836.
>=20
> Fixes early panic on Raspberry Pi 4B with MULITIPROCESSOR kernel:
>=20
> ---
> [   1.0000000] NetBSD/evbarm (fdt) booting ...
> [   1.0000000] [ Kernel symbol table missing! ]
> [   1.0000000] Fatal kernel mode prefetch abort at 0x00000000
> [   1.0000000] trapframe: 0x80b73ee8, spsr=3D600001d3
> [   1.0000000] r0 =3D00000000, r1 =3Df4000000, r2 =3D0000009c, r3 =3D010=
00380
> [   1.0000000] r4 =3D00000000, r5 =3D807a0484, r6 =3D00000001, r7 =3D80a=
4b180
> [   1.0000000] r8 =3D807a0470, r9 =3D805baab8, r10=3D807a0484, r11=3D80b=
73f54
> [   1.0000000] r12=3D7f000000, ssp=3D80b73f38, slr=3D80011170, pc =3D000=
00000
>=20
> Stopped in pid 0.0 (system) at  0:      address 0x0 is invalid
> adchis  r3, r7, r4, lsr #26
> db{0}>
> ---
>=20
> diff --git a/sys/arch/arm/broadcom/bcm283x_platform.c b/sys/arch/arm/bro=
adcom/bcm283x_platform.c
> index 8751d3af1236..7b553c6112ac 100644
> --- a/sys/arch/arm/broadcom/bcm283x_platform.c
> +++ b/sys/arch/arm/broadcom/bcm283x_platform.c
> @@ -872,7 +872,26 @@ cpu_enable_bcm2836(int phandle)
>  =20
>   	return 0;
>   }
> +
> +static int
> +cpu_enable_bcm2711(int phandle)
> +{
> +	bus_space_tag_t iot =3D &bcm2711_bs_tag;
> +	bus_space_handle_t ioh =3D BCM2711_ARM_LOCAL_VBASE;
> +	uint64_t mpidr;
> +
> +	fdtbus_get_reg64(phandle, 0, &mpidr, NULL);
> +
> +	const u_int cpuno =3D __SHIFTOUT(mpidr, MPIDR_AFF0);
> +
> +	bus_space_write_4(iot, ioh, BCM2836_LOCAL_MAILBOX3_SETN(cpuno),
> +	    KERN_VTOPHYS((vaddr_t)cpu_mpstart));
> +
> +	return 0;
> +}
>   ARM_CPU_METHOD(bcm2836, "brcm,bcm2836-smp", cpu_enable_bcm2836);
> +/* patched in src/sys/arch/arm/dts/bcm2711-cpus.dtsi */
> +ARM_CPU_METHOD(bcm2711, "brcm,bcm2711-smp", cpu_enable_bcm2711);
>   #endif
>  =20
>   #endif	/* SOC_BCM2836 */
> diff --git a/sys/arch/arm/dts/bcm2711-cpus.dtsi b/sys/arch/arm/dts/bcm27=
11-cpus.dtsi
> new file mode 100644
> index 000000000000..f55247eea2de
> --- /dev/null
> +++ b/sys/arch/arm/dts/bcm2711-cpus.dtsi
> @@ -0,0 +1,10 @@
> +/* $NetBSD$ */
> +
> +/*
> + * return "bcm2711-smp" instead of upstream default "bcm2836-smp"
> + * in bcm2711.dtsi to handle bcm2711 specific device addresses
> + */
> +
> +&cpus {
> +	enable-method =3D "brcm,bcm2711-smp";
> +};
> diff --git a/sys/arch/arm/dts/bcm2711-rpi-4-b.dts b/sys/arch/arm/dts/bcm=
2711-rpi-4-b.dts
> new file mode 100644
> index 000000000000..842aafa15363
> --- /dev/null
> +++ b/sys/arch/arm/dts/bcm2711-rpi-4-b.dts
> @@ -0,0 +1,5 @@
> +/* $NetBSD$ */
> +
> +#include "../../../external/gpl2/dts/dist/arch/arm64/boot/dts/broadcom/=
bcm2711-rpi-4-b.dts"
> +
> +#include "bcm2711-cpus.dtsi"
> diff --git a/sys/arch/arm/dts/bcm2711-rpi-400.dts b/sys/arch/arm/dts/bcm=
2711-rpi-400.dts
> new file mode 100644
> index 000000000000..473d0ef9c967
> --- /dev/null
> +++ b/sys/arch/arm/dts/bcm2711-rpi-400.dts
> @@ -0,0 +1,5 @@
> +/* $NetBSD$ */
> +
> +#include "../../../external/gpl2/dts/dist/arch/arm64/boot/dts/broadcom/=
bcm2711-rpi-400.dts"
> +
> +#include "bcm2711-cpus.dtsi"
> diff --git a/sys/arch/arm/dts/bcm2711-rpi-cm4-io.dts b/sys/arch/arm/dts/=
bcm2711-rpi-cm4-io.dts
> new file mode 100644
> index 000000000000..ac5fd8f34321
> --- /dev/null
> +++ b/sys/arch/arm/dts/bcm2711-rpi-cm4-io.dts
> @@ -0,0 +1,5 @@
> +/* $NetBSD$ */
> +
> +#include "../../../external/gpl2/dts/dist/arch/arm64/boot/dts/broadcom/=
bcm2711-rpi-cm4-io.dts"
> +
> +#include "bcm2711-cpus.dtsi"


LGTM


>=20
> ---
>=20
>> A custom "start4.elf" binary with patched strings from the original
>> "simple_bus" to "simple-bus" makes ofctl(8) return "simple-bus":
>>
>> ---
>> armv7# strings /boot/start4.elf.orig | grep simple
>> simple_bus
>> simple-framebuffer
>> simple_mode
>> simple_gpio_flash
>> simple
>> armv7# strings /boot/start4.elf | grep simple
>> simple-bus
>> simple-framebuffer
>> simple_mode
>> simple_gpio_flash
>> simple
>> armv7# ofctl -p /chosen name compatible
>> [Caching 258 nodes and 1436 properties]
>> name                    63686f73 656e00.. ........ ........   "chosen"
>> compatible              73696d70 6c652d62 757300.. ........   "simple-b=
us"
>> armv7#
>> ---
>>
>> (not sure how this should be handled)
>=20
> No idea how this should be handled.

I'm lost on this one.

Why do you think "simple_bus" needs to be allowed?



>=20
>>>>> Just use BUS_ADDR_{LO,HI}32
>>>>
>>>> I see.
>>>> (Note several other drivers like sys/dev/ic/dwc_eqos.c also use
>>>> "(uint32_t)((uint64_t)paddr >> 32)" formats)
>>>
>>> They're equally fugly and should use BUS_ADDR_{LO,HI}32
>>
>> Sure, I'll fix them when I will be motivated.
>=20
> https://github.com/tsutsui/netbsd-src/commit/50c26ba1ec7e2001752647e5ef3=
531d994668273
>=20
> ---
> bcmgenet: fix build errors on ILP32 targets
>=20
> Use BUS_ADDR_LO32() and BUS_ADDR_HI32() to handle 40 bit DMA addresses.
> genet(4) on Raspberry Pi 4B just works even on earmv7hf kernels.
>=20
> ---
>=20
> diff --git a/sys/dev/ic/bcmgenet.c b/sys/dev/ic/bcmgenet.c
> index 36c0cbfe1358..4b911097d0f1 100644
> --- a/sys/dev/ic/bcmgenet.c
> +++ b/sys/dev/ic/bcmgenet.c
> @@ -188,8 +188,8 @@ genet_setup_txdesc(struct genet_softc *sc, int index=
, int flags,
>  =20
>   	status =3D flags | __SHIFTIN(len, GENET_TX_DESC_STATUS_BUFLEN);
>  =20
> -	WR4(sc, GENET_TX_DESC_ADDRESS_LO(index), (uint32_t)paddr);
> -	WR4(sc, GENET_TX_DESC_ADDRESS_HI(index), (uint32_t)(paddr >> 32));
> +	WR4(sc, GENET_TX_DESC_ADDRESS_LO(index), BUS_ADDR_LO32(paddr));
> +	WR4(sc, GENET_TX_DESC_ADDRESS_HI(index), BUS_ADDR_HI32(paddr));
>   	WR4(sc, GENET_TX_DESC_STATUS(index), status);
>   }
>  =20
> @@ -258,8 +258,8 @@ static void
>   genet_setup_rxdesc(struct genet_softc *sc, int index,
>       bus_addr_t paddr, bus_size_t len)
>   {
> -	WR4(sc, GENET_RX_DESC_ADDRESS_LO(index), (uint32_t)paddr);
> -	WR4(sc, GENET_RX_DESC_ADDRESS_HI(index), (uint32_t)(paddr >> 32));
> +	WR4(sc, GENET_RX_DESC_ADDRESS_LO(index), BUS_ADDR_LO32(paddr));
> +	WR4(sc, GENET_RX_DESC_ADDRESS_HI(index), BUS_ADDR_HI32(paddr));
>   }
>  =20
>   static int
>=20


LGTM

Nick