[PATCH 02/16] arm: qemu: Explain how to extract the generate devicetree

[François Ozog]

Le mer. 13 oct. 2021 à 03:02, Simon Glass <sjg at chromium.org> a écrit :

> QEMU currently generates a devicetree for use with U-Boot. Explain how to
> obtain it.
>
> Signed-off-by: Simon Glass <sjg at chromium.org>
> ---
>
>  doc/board/emulation/qemu-arm.rst | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
>
> diff --git a/doc/board/emulation/qemu-arm.rst
> b/doc/board/emulation/qemu-arm.rst
> index 97b6ec64905..b458a398c69 100644
> --- a/doc/board/emulation/qemu-arm.rst
> +++ b/doc/board/emulation/qemu-arm.rst
> @@ -91,3 +91,15 @@ The debug UART on the ARM virt board uses these
> settings::
>      CONFIG_DEBUG_UART_PL010=y
>      CONFIG_DEBUG_UART_BASE=0x9000000
>      CONFIG_DEBUG_UART_CLOCK=0
> +
> +Obtaining the QEMU devicetree
> +-----------------------------
> +
> +QEMU generates its own devicetree to pass to U-Boot and does this by
> default.
> +You can use `-dtb u-boot.dtb` to force QEMU to use U-Boot's in-tree
> version.

this is for either Qemu experts or u-boot for Qemu maintainers. Not for the
kernel développer as it is recipe for problems: could you add this warning ?

>
> +
> +To obtain the devicetree that qemu generates, add `-machine
> dumpdtb=dtb.dtb`,
> +e.g.::
> +
> +    qemu-system-aarch64 -machine virt -nographic -cpu cortex-a57 \
> +           -bios u-boot.bin -machine dumpdtb=dtb.dtb
> --
> 2.33.0.882.g93a45727a2-goog
>
> --
François-Frédéric Ozog | *Director Business Development*
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