Re: [PATCH v7 2/3] arm64: dts: mediatek: add basic mt7986a support

[Matthias Brugger <matthias.bgg@gmail.com>]

Hi,

On 18/10/2021 13:40, Sam Shih wrote:
> Add basic chip support for Mediatek mt7986a, include
> basic uart nodes, rng node and watchdog node.
> 
> Add cpu node, timer node, gic node, psci and reserved-memory node
> for ARM Trusted Firmware.
> 

What is the exact difference between mt7986a and mt7986b? Right now, it's only 
the compatible, for that it makes no sense to split them.

It would be good to see what the exact differences are, so that we can see if it 
makes sense to have one of the alternatives:
1) use a common mt7986.dtsi which get included by mt7986[a,b].dtsi
2) Use on mt7986.dtsi and only add one mt7986a.dtsi or mt7986b.dtsi which has 
add-ons.

> Signed-off-by: Sam Shih <sam.shih@mediatek.com>
> 
> ---
> v7: added memory node back to dts
> v6: removed clock and pinctrl node, to separate basic part into a single
>      patch series
> 
> Original thread:
> https://lore.kernel.org/all/20211004124155.1404-1-sam.shih@mediatek.com/
> 
> v5: follow reviewr's comment: removed clock freqency node in timer due to
>      we have set CNTFRQ_EL0 in ATF firmware, and also corrected GICD range
> v4: added missing gic register bases, and fixed range of GICR
> v3: used the stdout-path instead of console=ttyS0
> v2: modified clock and uart node due to clock driver updated
> ---
>   arch/arm64/boot/dts/mediatek/Makefile        |   1 +
>   arch/arm64/boot/dts/mediatek/mt7986a-rfb.dts |  38 +++++
>   arch/arm64/boot/dts/mediatek/mt7986a.dtsi    | 149 +++++++++++++++++++
>   3 files changed, 188 insertions(+)
>   create mode 100644 arch/arm64/boot/dts/mediatek/mt7986a-rfb.dts
>   create mode 100644 arch/arm64/boot/dts/mediatek/mt7986a.dtsi
> 
> diff --git a/arch/arm64/boot/dts/mediatek/Makefile b/arch/arm64/boot/dts/mediatek/Makefile
> index 4f68ebed2e31..e6c3a73b9e4a 100644
> --- a/arch/arm64/boot/dts/mediatek/Makefile
> +++ b/arch/arm64/boot/dts/mediatek/Makefile
> @@ -7,6 +7,7 @@ dtb-$(CONFIG_ARCH_MEDIATEK) += mt6797-evb.dtb
>   dtb-$(CONFIG_ARCH_MEDIATEK) += mt6797-x20-dev.dtb
>   dtb-$(CONFIG_ARCH_MEDIATEK) += mt7622-rfb1.dtb
>   dtb-$(CONFIG_ARCH_MEDIATEK) += mt7622-bananapi-bpi-r64.dtb
> +dtb-$(CONFIG_ARCH_MEDIATEK) += mt7986a-rfb.dtb
>   dtb-$(CONFIG_ARCH_MEDIATEK) += mt8167-pumpkin.dtb
>   dtb-$(CONFIG_ARCH_MEDIATEK) += mt8173-elm.dtb
>   dtb-$(CONFIG_ARCH_MEDIATEK) += mt8173-elm-hana.dtb
> diff --git a/arch/arm64/boot/dts/mediatek/mt7986a-rfb.dts b/arch/arm64/boot/dts/mediatek/mt7986a-rfb.dts
> new file mode 100644
> index 000000000000..ca074cf8e578
> --- /dev/null
> +++ b/arch/arm64/boot/dts/mediatek/mt7986a-rfb.dts
> @@ -0,0 +1,38 @@
> +// SPDX-License-Identifier: (GPL-2.0 OR MIT)
> +/*
> + * Copyright (C) 2021 MediaTek Inc.
> + * Author: Sam.Shih <sam.shih@mediatek.com>
> + */
> +
> +/dts-v1/;
> +#include "mt7986a.dtsi"
> +
> +/ {
> +	model = "MediaTek MT7986a RFB";
> +	compatible = "mediatek,mt7986a-rfb";
> +
> +	aliases {
> +		serial0 = &uart0;
> +	};
> +
> +	chosen {
> +		stdout-path = "serial0:115200n8";
> +		bootargs = "earlycon=uart8250,mmio32,0x11002000 swiotlb=512";

We normally don't add earlycon parameter to the normal bootargs, as it's only 
for debugging. Also what do we need the swiotlb? Are there any limitation in the 
HW that makes us need it?

Regards,
Matthias

> +	};
> +
> +	memory {
> +		reg = <0 0x40000000 0 0x40000000>;
> +	};
> +};
> +
> +&uart0 {
> +	status = "okay";
> +};
> +
> +&uart1 {
> +	status = "okay";
> +};
> +
> +&uart2 {
> +	status = "okay";
> +};
> diff --git a/arch/arm64/boot/dts/mediatek/mt7986a.dtsi b/arch/arm64/boot/dts/mediatek/mt7986a.dtsi
> new file mode 100644
> index 000000000000..75912bcf6c9c
> --- /dev/null
> +++ b/arch/arm64/boot/dts/mediatek/mt7986a.dtsi
> @@ -0,0 +1,149 @@
> +// SPDX-License-Identifier: (GPL-2.0 OR MIT)
> +/*
> + * Copyright (C) 2021 MediaTek Inc.
> + * Author: Sam.Shih <sam.shih@mediatek.com>
> + */
> +
> +#include <dt-bindings/interrupt-controller/irq.h>
> +#include <dt-bindings/interrupt-controller/arm-gic.h>
> +
> +/ {
> +	compatible = "mediatek,mt7986a";
> +	interrupt-parent = <&gic>;
> +	#address-cells = <2>;
> +	#size-cells = <2>;
> +
> +	system_clk: dummy40m {
> +		compatible = "fixed-clock";
> +		clock-frequency = <40000000>;
> +		#clock-cells = <0>;
> +	};
> +
> +	cpus {
> +		#address-cells = <1>;
> +		#size-cells = <0>;
> +		cpu0: cpu@0 {
> +			device_type = "cpu";
> +			compatible = "arm,cortex-a53";
> +			enable-method = "psci";
> +			reg = <0x0>;
> +			#cooling-cells = <2>;
> +		};
> +
> +		cpu1: cpu@1 {
> +			device_type = "cpu";
> +			compatible = "arm,cortex-a53";
> +			enable-method = "psci";
> +			reg = <0x1>;
> +			#cooling-cells = <2>;
> +		};
> +
> +		cpu2: cpu@2 {
> +			device_type = "cpu";
> +			compatible = "arm,cortex-a53";
> +			enable-method = "psci";
> +			reg = <0x2>;
> +			#cooling-cells = <2>;
> +		};
> +
> +		cpu3: cpu@3 {
> +			device_type = "cpu";
> +			enable-method = "psci";
> +			compatible = "arm,cortex-a53";
> +			reg = <0x3>;
> +			#cooling-cells = <2>;
> +		};
> +	};
> +
> +	psci {
> +		compatible  = "arm,psci-0.2";
> +		method      = "smc";
> +	};
> +
> +	reserved-memory {
> +		#address-cells = <2>;
> +		#size-cells = <2>;
> +		ranges;
> +		/* 192 KiB reserved for ARM Trusted Firmware (BL31) */
> +		secmon_reserved: secmon@43000000 {
> +			reg = <0 0x43000000 0 0x30000>;
> +			no-map;
> +		};
> +	};
> +
> +	timer {
> +		compatible = "arm,armv8-timer";
> +		interrupt-parent = <&gic>;
> +		interrupts = <GIC_PPI 13 IRQ_TYPE_LEVEL_LOW>,
> +			     <GIC_PPI 14 IRQ_TYPE_LEVEL_LOW>,
> +			     <GIC_PPI 11 IRQ_TYPE_LEVEL_LOW>,
> +			     <GIC_PPI 10 IRQ_TYPE_LEVEL_LOW>;
> +	};
> +
> +	soc {
> +		#address-cells = <2>;
> +		#size-cells = <2>;
> +		compatible = "simple-bus";
> +		ranges;
> +
> +		gic: interrupt-controller@c000000 {
> +			compatible = "arm,gic-v3";
> +			#interrupt-cells = <3>;
> +			interrupt-parent = <&gic>;
> +			interrupt-controller;
> +			reg = <0 0x0c000000 0 0x10000>,  /* GICD */
> +			      <0 0x0c080000 0 0x80000>,  /* GICR */
> +			      <0 0x0c400000 0 0x2000>,   /* GICC */
> +			      <0 0x0c410000 0 0x1000>,   /* GICH */
> +			      <0 0x0c420000 0 0x2000>;   /* GICV */
> +			interrupts = <GIC_PPI 9 IRQ_TYPE_LEVEL_HIGH>;
> +		};
> +
> +		watchdog: watchdog@1001c000 {
> +			compatible = "mediatek,mt7986-wdt",
> +				     "mediatek,mt6589-wdt";
> +			reg = <0 0x1001c000 0 0x1000>;
> +			interrupts = <GIC_SPI 110 IRQ_TYPE_LEVEL_HIGH>;
> +			#reset-cells = <1>;
> +			status = "disabled";
> +		};
> +
> +		trng: trng@1020f000 {
> +			compatible = "mediatek,mt7986-rng",
> +				     "mediatek,mt7623-rng";
> +			reg = <0 0x1020f000 0 0x100>;
> +			clocks = <&system_clk>;
> +			clock-names = "rng";
> +			status = "disabled";
> +		};
> +
> +		uart0: serial@11002000 {
> +			compatible = "mediatek,mt7986-uart",
> +				     "mediatek,mt6577-uart";
> +			reg = <0 0x11002000 0 0x400>;
> +			interrupts = <GIC_SPI 123 IRQ_TYPE_LEVEL_HIGH>;
> +			clocks = <&system_clk>;
> +			status = "disabled";
> +		};
> +
> +		uart1: serial@11003000 {
> +			compatible = "mediatek,mt7986-uart",
> +				     "mediatek,mt6577-uart";
> +			reg = <0 0x11003000 0 0x400>;
> +			interrupts = <GIC_SPI 124 IRQ_TYPE_LEVEL_HIGH>;
> +			clocks = <&system_clk>;
> +			status = "disabled";
> +		};
> +
> +		uart2: serial@11004000 {
> +			compatible = "mediatek,mt7986-uart",
> +				     "mediatek,mt6577-uart";
> +			reg = <0 0x11004000 0 0x400>;
> +			interrupts = <GIC_SPI 125 IRQ_TYPE_LEVEL_HIGH>;
> +			clocks = <&system_clk>;
> +			status = "disabled";
> +		};
> +
> +	};
> +
> +};
>