[PATCH v2 1/1] doc: U-Boot boot phases

[Simon Glass]

Hi Heinrich,

On Fri, 28 Jul 2023 at 09:58, Heinrich Schuchardt
<heinrich.schuchardt at canonical.com> wrote:
>
> Add more detail to the description of U-Boot boot phases:
>
> * describe which steps are optional
> * mentions alternative boot flows
>
> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
> Reviewed-by: Bin Meng <bmeng.cn at gmail.com>
> ---
> v2:
>         add missing comma
> ---
>  doc/develop/spl.rst | 13 ++++++++++---
>  1 file changed, 10 insertions(+), 3 deletions(-)
>
> diff --git a/doc/develop/spl.rst b/doc/develop/spl.rst
> index a1515a7b43..5743bdf37c 100644
> --- a/doc/develop/spl.rst
> +++ b/doc/develop/spl.rst
> @@ -77,10 +77,11 @@ To check whether a feature is enabled, use CONFIG_IS_ENABLED()::
>  This checks CONFIG_CLK for the main build, CONFIG_SPL_CLK for the SPL build,
>  CONFIG_TPL_CLK for the TPL build, etc.
>
> -U-Boot Phases
> --------------
> +U-Boot Boot Phases
> +------------------
>
> -U-Boot boots through the following phases:
> +U-Boot goes through the following boot phases where TPL, VPL, SPL are optional.
> +While many boards use SPL, less use TPL.
>
>  TPL
>     Very early init, as tiny as possible. This loads SPL (or VPL if enabled).
> @@ -97,6 +98,12 @@ SPL
>  U-Boot
>     U-Boot proper, containing the command line and boot logic.
>
> +Further usages of U-Boot SPL comprise:
> +
> +* Launching BL31 of ARM Trusted Firmware which invokes main U-Boot as BL33
> +* launching EDK II

Really? Where are the instructions for that?

> +* launching Linux kernel

This is falcon boot, is it? Can we link to the docs?

> +* launching RISC-V OpenSBI which invokes main U-Boot
>
>  Checking the boot phase
>  -----------------------
> --
> 2.40.1
>

Regards,
Simon