[PATCH] Documentation: devicetree: list automatic boot argument fixups

Ahmad Fatoum a.fatoum at pengutronix.de
Fri Mar 17 04:15:26 PDT 2023


Hello Johannes,

Thanks for documenting this. Some minor suggestions below.

On 17.03.23 12:07, Johannes Zink wrote:
> Barebox automatically fixes up several entries to the root and

s/entries/properties/

> chosen-node of the devicetree passed to the booted system.

chosen node, device tree

> 
> These entries contain information about the hardware, reset source
> and the barebox version string.
> 
> Add documentation on how to query these information from the booted
> linux system.
> 
> Signed-off-by: Johannes Zink <j.zink at pengutronix.de>
> ---
>  Documentation/devicetree/index.rst | 21 +++++++++++++++++++++
>  1 file changed, 21 insertions(+)
> 
> diff --git a/Documentation/devicetree/index.rst b/Documentation/devicetree/index.rst
> index 36fa69058d1d..92a91dc35a11 100644
> --- a/Documentation/devicetree/index.rst
> +++ b/Documentation/devicetree/index.rst
> @@ -151,3 +151,24 @@ Contents:
>     bindings/regulator/*
>     bindings/rtc/*
>     bindings/watchdog/*
> +
> +automatic boot argument fixups to the devicetree

Title case or at least a capital letter at the beginning?

> +------------------------------------------------
> +
> +Barebox automatically fixes up some arguments in the devicetree.

s/Barebox/barebox/, s/devicetree/device tree/, s/arguments/properties/
or information.

> +
> +In the devicetree root barebox fixes up

, barebox

> +
> + * serial-number (if available)
> + * machine compatible (if available)

s/available/overridden/
There's nearly always a machine compatible.

> +
> +In the ``chosen``-node barebox fixes up

, barebox

> +
> + * barebox-version
> + * reset-source
> + * reset-source-instance (if available)
> + * reset-source-device (phandle, only if available)

node path, not the numeric phandle, compare

 property = &path -> "/path/to/something"

vs.

 property = <&path> -> <0x23>, with &path { phandle = <0x23>; }

> + * bootsource
> + * boot-hartid (only on RISCV)

RISC-V

> +
> +These values can be read from the booted linux system in ``/proc/device-tree/`

"or /sys/firmware/devicetree/base".


Thanks,
Ahmad

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