[U-Boot] [PATCH 1/1] efi_loader: use built-in device tree in bootefi command

[Alexander Graf]

On 01/20/2018 01:56 PM, Heinrich Schuchardt wrote:
> The bootefi command has two parameters: the address of the executable and
> the address of the flattened device tree.
>
> When executing the devicetree command in grub this command can only
> replace an existing device tree. So we always want to pass a device tree.
>
> With the patch the device tree defaults to the internal one. But of cause
> the user still can supply his one via the second parameter.
>
> One use case is booting via iPXE from an iSCSI drive. As we may be able
> to choose between different operating systems in the iPXE menu we cannot
> know the correct device tree when invoking bootefi. The dtb might not even
> be installed on a local device.
>
> Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>

All of this logic is already implemented in the distro boot script, so 
if you load your iPXE EFI binary via dhcp boot, from a block device or 
something similar, it will by default already get $fdtcontroladdr passed 
in. I'm not sure I'm terribly happy to have additional magic in the 
bootefi command. If you want to spawn an EFI binary without device tree 
table, you should be able to do so IMHO.

How do you invoke iPXE?


Alex