[ipxe-devel] [PATCH 1/1] efi: provide possibility to disable cpu_nap

Heinrich Schuchardt xypron.glpk at gmx.de
Wed Jul 12 17:57:39 UTC 2017

On 07/12/2017 07:47 PM, Michael Brown wrote:
> On 12/07/17 18:45, Heinrich Schuchardt wrote:
>> U-Boot runs single-threaded without interrupts.
>> When cpu_nap is called the process is never woken up again.
> #ifdef is not allowed for this sort of fix, sorry.

What is your suggestion?

> How are you running iPXE inside U-Boot?  What firmware interface does
> U-Boot provide that iPXE understands?  (UEFI?)

U-Boot implements an (still incomplete) UEFI environment based on the
UEFI 2.7 spec.
It provides a console, access to the block device, and the Simple
Network Protocol.

You can start snponly.efi like this:

load mmc 0:1 0x1000000 dtb
load mmc 0:1 0x13000000 snponly.efi
bootefi 0x13000000 0x1000000

The addresses and the partition of cause depend on your system.

Currently I am also writing patches to add the missing UEFI parts in U-Boot.

I was able to reach the iPXE console. There are still some parts missing
to make use of the network.

Best regards

Heinrich Schuchardt

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