[PATCH] ARM64: juno: add NOR flash to device tree

Leif Lindholm leif.lindholm at linaro.org
Mon Oct 19 04:27:49 PDT 2015


On Mon, Oct 19, 2015 at 01:19:14PM +0200, Linus Walleij wrote:
> On Mon, Oct 19, 2015 at 12:29 PM, Mark Rutland <mark.rutland at arm.com> wrote:
> 
> > Also, for non U-Boot systems I was under the impression that the flash
> > was effectively owned by EFI (for variable storage),
> 
> If it is "owned" by something it is owned by the boot monitor, neither
> by U-Boot or (U)EFI. The boot monitor can flash "images" into
> the flash using USB or ethernet/TFTP and it is not part of any
> boot loader, but an autonomous flash image on the board.
> (Actually it can replace itself.)

No.

This would be true for any preceding ARM devboard, but Juno's boot
architecture is different. The thing that gives the 'Cmd>' prompt is
running on a system microcontroller. It writes images to the system
NOR based on the contents of images.txt in the magic USB filesystem.

While I think you _can_ run the boot monitor on Juno, it it not part
of the UEFI boot path, and I didn't think it was for U-Boot either?
It certainly shouldn't be needed.

/
    Leif



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