[PATCH 2/2] arm: dts: mt6589: Add device tree for Fairphone 1

[Matthias Brugger]

On 05/10/2021 22:28, Luca Weiss wrote:
> Add rudimentary support for the Fairphone 1, based on MT6589 to boot to
> UART console.
> 
> The recently added SMP support needs to be disabled for this board as
> the kernel panics executing /init with it, even though the CPUs seem to
> start up fine - maybe a stability issue.
> 
> [    0.072010] smp: Bringing up secondary CPUs ...
> [    0.131888] CPU1: thread -1, cpu 1, socket 0, mpidr 80000001
> [    0.191889] CPU2: thread -1, cpu 2, socket 0, mpidr 80000002
> [    0.251890] CPU3: thread -1, cpu 3, socket 0, mpidr 80000003
> [    0.251982] smp: Brought up 1 node, 4 CPUs
> [    0.254745] SMP: Total of 4 processors activated (7982.28 BogoMIPS).
> [    0.255582] CPU: All CPU(s) started in SVC mode.
> 
> [    0.472039] Run /init as init process
> [    0.473317] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000004
> 

Would be nice to find out why. Did you tried to boot the system with 
enable-method set but with bringing up just one or two cpus?

> Signed-off-by: Luca Weiss <luca at z3ntu.xyz>
> ---
>   arch/arm/boot/dts/Makefile                 |  1 +
>   arch/arm/boot/dts/mt6589-fairphone-fp1.dts | 30 ++++++++++++++++++++++
>   2 files changed, 31 insertions(+)
>   create mode 100644 arch/arm/boot/dts/mt6589-fairphone-fp1.dts
> 
> diff --git a/arch/arm/boot/dts/Makefile b/arch/arm/boot/dts/Makefile
> index 7e0934180724..24f402db2613 100644
> --- a/arch/arm/boot/dts/Makefile
> +++ b/arch/arm/boot/dts/Makefile
> @@ -1437,6 +1437,7 @@ dtb-$(CONFIG_ARCH_MEDIATEK) += \
>   	mt2701-evb.dtb \
>   	mt6580-evbp1.dtb \
>   	mt6589-aquaris5.dtb \
> +	mt6589-fairphone-fp1.dtb \
>   	mt6592-evb.dtb \
>   	mt7623a-rfb-emmc.dtb \
>   	mt7623a-rfb-nand.dtb \
> diff --git a/arch/arm/boot/dts/mt6589-fairphone-fp1.dts b/arch/arm/boot/dts/mt6589-fairphone-fp1.dts
> new file mode 100644
> index 000000000000..32c14ecf2244
> --- /dev/null
> +++ b/arch/arm/boot/dts/mt6589-fairphone-fp1.dts
> @@ -0,0 +1,30 @@
> +// SPDX-License-Identifier: BSD-3-Clause
> +/*
> + * Copyright (c) 2021, Luca Weiss <luca at z3ntu.xyz>
> + */
> +
> +/dts-v1/;
> +#include "mt6589.dtsi"
> +
> +/ {
> +	model = "Fairphone 1";
> +	compatible = "fairphone,fp1", "mediatek,mt6589";
> +
> +	chosen {
> +		stdout-path = &uart3;
> +	};
> +
> +	cpus {

I'd expected "&cpus" why can we overwrite delete the node property like this here?

> +		/* SMP is not stable on this board, makes the kernel panic */
> +		/delete-property/ enable-method;
> +	};
> +
> +	memory {
> +		device_type = "memory";
> +		reg = <0x80000000 0x40000000>;
> +	};
> +};
> +
> +&uart3 {
> +	status = "okay";
> +};
>