[PATCH RFC] arm64: dts: Use separate dtb for Khadas vim3 usb3 and pcie controller

[Neil Armstrong]

Hi,

On 15/11/2020 04:39, Qu Wenruo wrote:
> Although the plan is to make the bootloader (U-boot) to load overlay for
> the device, but currently the board doesn't have the upstream support
> yet.

No need for that, automatic PCIe enable is now support on upstream U-Boot
for VIM3 & VIM3L:
https://github.com/u-boot/u-boot/commit/adbff64af7b7cee3e0007b75df2644090edaafcb

Neil

> 
> This means even upstream kernel supports all the needed drivers, we still
> can't initialize the pcie controller.
> 
> As a workaround, make seperate device trees for pcie controller and usb3
> controller.
> 
> Now user still need to go into the factory bootloader to switch the mux,
> but they can easily boot the kernel with PCIE support by just swithcing
> to the pcie device tree.
> 
> And since we didn't modify the original dtb, the future upstream uboot
> can still use overlay to switch mode using the same dtb file.
> The added new pcie dtb will just be a workaround.
> 
> Tested on my VIM3 pro board, now I can boot the root fs on the NVME
> drive, with upstream kernel with the new pcie dtb.
> 
> Signed-off-by: Qu Wenruo <wqu at suse.com>
> ---
>  arch/arm64/boot/dts/amlogic/Makefile          |  1 +
>  .../meson-g12b-a311d-khadas-vim3-pcie.dts     | 39 +++++++++++++++++++
>  .../amlogic/meson-g12b-a311d-khadas-vim3.dts  | 23 +----------
>  3 files changed, 41 insertions(+), 22 deletions(-)
>  create mode 100644 arch/arm64/boot/dts/amlogic/meson-g12b-a311d-khadas-vim3-pcie.dts
> 
> diff --git a/arch/arm64/boot/dts/amlogic/Makefile b/arch/arm64/boot/dts/amlogic/Makefile
> index ced03946314f..a0b8d30539e2 100644
> --- a/arch/arm64/boot/dts/amlogic/Makefile
> +++ b/arch/arm64/boot/dts/amlogic/Makefile
> @@ -6,6 +6,7 @@ dtb-$(CONFIG_ARCH_MESON) += meson-g12a-x96-max.dtb
>  dtb-$(CONFIG_ARCH_MESON) += meson-g12b-gtking.dtb
>  dtb-$(CONFIG_ARCH_MESON) += meson-g12b-gtking-pro.dtb
>  dtb-$(CONFIG_ARCH_MESON) += meson-g12b-a311d-khadas-vim3.dtb
> +dtb-$(CONFIG_ARCH_MESON) += meson-g12b-a311d-khadas-vim3-pcie.dtb
>  dtb-$(CONFIG_ARCH_MESON) += meson-g12b-s922x-khadas-vim3.dtb
>  dtb-$(CONFIG_ARCH_MESON) += meson-g12b-odroid-n2.dtb
>  dtb-$(CONFIG_ARCH_MESON) += meson-g12b-odroid-n2-plus.dtb
> diff --git a/arch/arm64/boot/dts/amlogic/meson-g12b-a311d-khadas-vim3-pcie.dts b/arch/arm64/boot/dts/amlogic/meson-g12b-a311d-khadas-vim3-pcie.dts
> new file mode 100644
> index 000000000000..93641a32eeec
> --- /dev/null
> +++ b/arch/arm64/boot/dts/amlogic/meson-g12b-a311d-khadas-vim3-pcie.dts
> @@ -0,0 +1,39 @@
> +// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
> +/*
> + * Copyright (c) 2019 BayLibre, SAS
> + * Author: Neil Armstrong <narmstrong at baylibre.com>
> + * Copyright (c) 2019 Christian Hewitt <christianshewitt at gmail.com>
> + */
> +
> +/dts-v1/;
> +
> +#include "meson-g12b-a311d.dtsi"
> +#include "meson-khadas-vim3.dtsi"
> +#include "meson-g12b-khadas-vim3.dtsi"
> +
> +/ {
> +	compatible = "khadas,vim3", "amlogic,a311d", "amlogic,g12b";
> +};
> +
> +/*
> + * The VIM3 on-board  MCU can mux the PCIe/USB3.0 shared differential
> + * lines using a FUSB340TMX USB 3.1 SuperSpeed Data Switch between
> + * an USB3.0 Type A connector and a M.2 Key M slot.
> + * The PHY driving these differential lines is shared between
> + * the USB3.0 controller and the PCIe Controller, thus only
> + * a single controller can use it.
> + *
> + * This is the PCIE device tree.
> + *
> + * Until upstream uboot can boot the board and modify the nodes before booting
> + * It's much easier to just choose this device tree file to use PCIE controller.
> + */
> +
> +&pcie {
> +	status = "okay";
> +};
> +
> +&usb {
> +	phys = <&usb2_phy0>, <&usb2_phy1>;
> +	phy-names = "usb2-phy0", "usb2-phy1";
> +};
> diff --git a/arch/arm64/boot/dts/amlogic/meson-g12b-a311d-khadas-vim3.dts b/arch/arm64/boot/dts/amlogic/meson-g12b-a311d-khadas-vim3.dts
> index 124a80901084..9c111d76baec 100644
> --- a/arch/arm64/boot/dts/amlogic/meson-g12b-a311d-khadas-vim3.dts
> +++ b/arch/arm64/boot/dts/amlogic/meson-g12b-a311d-khadas-vim3.dts
> @@ -16,26 +16,5 @@ / {
>  };
>  
>  /*
> - * The VIM3 on-board  MCU can mux the PCIe/USB3.0 shared differential
> - * lines using a FUSB340TMX USB 3.1 SuperSpeed Data Switch between
> - * an USB3.0 Type A connector and a M.2 Key M slot.
> - * The PHY driving these differential lines is shared between
> - * the USB3.0 controller and the PCIe Controller, thus only
> - * a single controller can use it.
> - * If the MCU is configured to mux the PCIe/USB3.0 differential lines
> - * to the M.2 Key M slot, uncomment the following block to disable
> - * USB3.0 from the USB Complex and enable the PCIe controller.
> - * The End User is not expected to uncomment the following except for
> - * testing purposes, but instead rely on the firmware/bootloader to
> - * update these nodes accordingly if PCIe mode is selected by the MCU.
> - */
> -/*
> -&pcie {
> -	status = "okay";
> -};
> -
> -&usb {
> -	phys = <&usb2_phy0>, <&usb2_phy1>;
> -	phy-names = "usb2-phy0", "usb2-phy1";
> -};
> + * Vim3 default to USB3.0 instead of PCIE controller.
>   */
>