[U-Boot] [PATCH 8/9] efi_loader: Add "bootefi" command

[Leif Lindholm]

On Fri, Dec 25, 2015 at 10:25:22AM +0100, Andreas Färber wrote:
> Am 25.12.2015 um 10:02 schrieb Alexander Graf:
> [snip]
> > The reason I implemented "bootefi" was really because it's the natural
> > fit into how U-Boot handles all other formats today. I don't think this
> > is going to be the last patch set around EFI support.
> 
> I think what Matwey was suggesting is integrating your "bootefi" into
> the standard "distro" boot sequence environment, so that it probes each
> device for an EFI binary and if it finds one runs load and bootefi,
> without the need for any boot.scr.
> 
> That would be a follow-up patch.
> 
> It however conflicts with your idea of having some potentially
> board-specific code mess with "fdt addr" command before running "bootefi".

This could however be resolved by moving to a model where the
device-tree was considered a component of the firmware (which is how
we treat it in UEFI). If U-Boot had an awareness (if it does not
already) of an FDT being something it should have and know about, then
this could trivially be passed onto bootefi.
This could means a "default_fdt" environment variable which is loaded
automatically before bootcmd is executed.

> My solution would be to give boot.scr preference over *.efi, so that the
> user has a way to load dtb and run "bootefi" on his own, and otherwise
> fall back to just "bootefi" which'll spit a warning about lack of fdt if
> I read that correctly.

An explicit bootscript should always override a fallback boot option.
And booting the "removable boot path" is a fallback boot option.

Regards,

Leif