[PATCH 6/6 v2] doc: Update uefi documentation for initrd loading options

[Heinrich Schuchardt]

On 3/13/21 10:47 PM, Ilias Apalodimas wrote:
> Document the command line options for efidebug and initrd loading
>
> Signed-off-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>
> ---
>   doc/uefi/uefi.rst | 21 ++++++++++++++++++++-
>   1 file changed, 20 insertions(+), 1 deletion(-)
>
> diff --git a/doc/uefi/uefi.rst b/doc/uefi/uefi.rst
> index b3494c22e073..76402bc5cfaa 100644
> --- a/doc/uefi/uefi.rst
> +++ b/doc/uefi/uefi.rst
> @@ -180,6 +180,12 @@ Set up boot parameters on your board::
>
>       efidebug boot add -b 1 HELLO mmc 0:1 /helloworld.efi.signed ""
>
> +Since kernel 5.7 there's an alternative way of loading an initrd using
> +LoadFile2 protocol if CONFIG_EFI_LOAD_FILE2_INITRD is enabled.
> +The initrd path can be specified with::
> +
> +    efidebug boot add -b ABE0 'kernel' mmc 0:1 Image -i mmc 0:1 initrd
> +
>   Now your board can run the signed image via the boot manager (see below).
>   You can also try this sequence by running Pytest, test_efi_secboot,
>   on the sandbox
> @@ -484,7 +490,20 @@ The load file 2 protocol can be used by the Linux kernel to load the initial
>   RAM disk. U-Boot can be configured to provide an implementation with::
>
>       EFI_LOAD_FILE2_INITRD=y
> -    EFI_INITRD_FILESPEC=interface dev:part path_to_initrd

Thanks for adding the description. Some nitpicky comments below:

> +
> +When the options is enabled the user can add the initrd path with the efidebug

%s/options/option/

> +command.
> +The Boot#### option has a FilePathList[] in it's EFI_LOAD_OPTION.

Load options Boot#### have a FilePathList[] member.

> +The first element of the array (FilePathList[0]) is the loded image.

is the EFI binary to execute.

> +When an initrd is specified the Device Path for the initrd is denoted by a
> +VenMedia node with the EFI_INITRD_MEDIA_GUID. Each entry of the array is
> +terminated by the 'end of entire device path' subtype. If the user wants to

Below you have (0x01). So add (0xff) here.

> +define multiple initrds those must by separated by the 'end of this instance'

%s/initrds/initrds,/

> +identifier of the end node (0x01).
> +
> +So our final format of the FilePathList[] is::
> +
> +    Loaded image - end node (0xff) - VenMedia - initrd1 - end node (0x01) initrd2 - end node (0xff)

Loaded image - end node (0xff) - VenMedia - initrd_1 -
[end node (0x01) - initrd_n ...] - end node (0xff)

There can be any number of initrds?

Best regards

Heinrich

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