[PATCH 4/7] arm: juno: Enable OF_CONTROL

Linus Walleij linus.walleij at linaro.org
Fri Mar 27 22:22:20 CET 2020

On Wed, Mar 25, 2020 at 3:47 PM Andre Przywara <andre.przywara at arm.com> wrote:

> The Arm Juno board was still somewhat stuck in "hardcoded land", even
> though there are stable DTs around, and one happens to actually be on
> the memory mapped NOR flash.
> Enable the configuration options to let the board use OF_CONTROL, and
> add a routine to find the address of the DTB partition in NOR
> flash, to use that for U-Boot's own purposes.
> This can also passed on via $fdtcontroladdr to any kernel or EFI
> application, removing the need to actually load a device tree.
> Since the existing "afs" command and its flash routines require
> flash_init() to be called before being usable, and this is done much
> later in the boot process, we introduce a stripped-down partition finder
> routine in vexpress64.c, to scan the NOR flash partitions for the
> DT partition. This location is then used for U-Boot to find and probe
> devices.
> The name of the partition can be configured, if needed, but defaults
> to "board.dtb", which is used by Linaro's firmware image provided.
> Signed-off-by: Andre Przywara <andre.przywara at arm.com>

It's a bit of duplication but what can we do. We need to inspect the
flash to find the DTB that defines where the flash is. We can certainly
live with this bootstrapping as a compromise.
Reviewed-by: Linus Walleij <linus.walleij at linaro.org>

Linus Walleij

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