[PATCH v7 09/31] arm: xenguest_arm64: Add a empty devicetree file

[Oleksandr Andrushchenko]

Hi, Simon!

On 07.12.21 02:11, Simon Glass wrote:
> Add an empty file to prevent build errors when building with
> CONFIG_OF_SEPARATE enabled.
>
> The build instructions in U-Boot do not provide enough detail to build a
> useful devicetree, unfortunately.
There is no such instruction exists as the device tree is built at run-time
by the hypervisor itself depending on virtual machine configuration:
I have already pointed that, e.g. U-boot is no different from any other
kernel/binary running in a virtual machine.

Thus I do not agree with the sentence above as it misleads.
>
> Signed-off-by: Simon Glass <sjg at chromium.org>
> ---
>
> Changes in v7:
> - Use 'empty' instead of 'fake'
>
>   arch/arm/dts/Makefile            |  2 ++
>   arch/arm/dts/xenguest-arm64.dts  | 15 +++++++++++++++
>   configs/xenguest_arm64_defconfig |  2 +-
>   3 files changed, 18 insertions(+), 1 deletion(-)
>   create mode 100644 arch/arm/dts/xenguest-arm64.dts
>
> diff --git a/arch/arm/dts/Makefile b/arch/arm/dts/Makefile
> index d53bae2c350..f6345988c8c 100644
> --- a/arch/arm/dts/Makefile
> +++ b/arch/arm/dts/Makefile
> @@ -1140,6 +1140,8 @@ dtb-$(CONFIG_ARCH_MEDIATEK) += \
>   	mt8516-pumpkin.dtb \
>   	mt8518-ap1-emmc.dtb
>   
> +dtb-$(CONFIG_XEN) += xenguest-arm64.dtb
> +
>   dtb-$(CONFIG_TARGET_GE_BX50V3) += \
>   	imx6q-bx50v3.dtb \
>   	imx6q-b850v3.dtb \
> diff --git a/arch/arm/dts/xenguest-arm64.dts b/arch/arm/dts/xenguest-arm64.dts
> new file mode 100644
> index 00000000000..d8734433763
> --- /dev/null
> +++ b/arch/arm/dts/xenguest-arm64.dts
> @@ -0,0 +1,15 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Empty devicetree file for xenguest_arm64
> + *
> + * This is required to make the board build with CONFIG OF_SEPARATE
> + * Build instructions at xenguest_arm64.rst are inadequate for obtaining a real
> + * devicetree.
ditto. I will not provide any instruction as this is internal to Xen implementation
and may change depending on Xen version and virtual machine configuration.
If someone wants that she can dig into relevant Xen sources to see how the
device tree constructed. But this may be different between Xen versions and/or
virtual machine settings.

Please rephrase to reflect the dynamic nature of the device tree instead

Thank you,
Oleksandr
> + *
> + * Copyright 2021 Google LLC
> + */
> +
> +/dts-v1/;
> +
> +/ {
> +};
> diff --git a/configs/xenguest_arm64_defconfig b/configs/xenguest_arm64_defconfig
> index 8d9d9133a2e..edce34346d3 100644
> --- a/configs/xenguest_arm64_defconfig
> +++ b/configs/xenguest_arm64_defconfig
> @@ -3,7 +3,7 @@ CONFIG_POSITION_INDEPENDENT=y
>   CONFIG_TARGET_XENGUEST_ARM64=y
>   CONFIG_SYS_TEXT_BASE=0x40080000
>   CONFIG_SYS_MALLOC_LEN=0x2000000
> -CONFIG_SYS_MALLOC_F_LEN=0x2000
> +CONFIG_DEFAULT_DEVICE_TREE="xenguest-arm64"
>   CONFIG_IDENT_STRING=" xenguest"
>   CONFIG_SYS_LOAD_ADDR=0x40000000
>   CONFIG_BOOTDELAY=10