[U-Boot] U-boot 2017.07 not working on Raspberry Pi

[Mark Kettenis]

> From: Paul Barker <pbarker at toganlabs.com>
> Date: Fri, 4 Aug 2017 13:58:50 +0100
> 
> On Thu, Aug 3, 2017 at 2:45 PM, Simon Glass <sjg at chromium.org> wrote:
> > Hi,
> >
> > On 3 August 2017 at 03:37, Mark Kettenis <mark.kettenis at xs4all.nl> wrote:
> >>> Date: Thu, 3 Aug 2017 19:02:06 +1000
> >>> From: Jonathan Gray <jsg at jsg.id.au>
> >>>
> >>>
> >>> We had to revert 25877d4e4c45451c5398aec3de50e0d5befe0e9f to add
> >>> CONFIG_OF_EMBED back to get OpenBSD to continue working on the rpi3.
> >>
> >> That revert is in particular necessary for passthrough of the device
> >> tree from the Raspberry Pi firmwre to work.  I haven't investigated
> >> this further yet, but it seems some of the relocation code is
> >> conditionalized on CONFIG_OF_EMBED, and I suspect that when
> >> CONFIG_OF_EMBED is absent, u-boot overwrites the device tree when it
> >> relocates itself.
> >
> > I'm not sure why it needs CONFIG_OF_EMBED. Certainly U-Boot does
> > relocate the DT when this is not set. But it should not be set for
> > production images, only for debugging.
> >
> 
> I've tried reverting just "dm: arm: rpi: Drop CONFIG_OF_EMBED"
> (25877d4e) but I'm still left without a working keyboard in u-boot -
> hitting keys during the countdown does not interrupt the boot process.
> However the kernel can be booted with just that one commit reverted.
> 
> I've also looking into the CONFIG_OF_BOARD option. This is currently
> disabled for raspberrypi devices which means that
> board_fdt_blob_setup() in board/raspberrypi/rpi/rpi.c is not called.
> Enabling CONFIG_OF_BOARD leads to a crash at boot with no output from
> u-boot, the monitor connected to the raspberrypi just shows the colour
> palette.
> 
> I can look into this further but it probably needs to wait until I can
> order some RS232 adaptors and get a serial port setup for early debug
> output.

FWIW, I tried to enable CONFIG_OF_BOARD as well as an alternative to
re-enabling CONFIG_OF_EMBED and didn't see any output on serial
console in that case either.  So debugging this probably requires
enabling some more debug output.