rk3399-gru-kevin: issues on bringup

[Simon Glass]

Hi Marty,

On Tue, 23 Feb 2021 at 16:36, Marty E. Plummer <hanetzer at startmail.com> wrote:
>
> On Tue, Feb 23, 2021 at 10:10:11AM -0500, Simon Glass wrote:
> > Hi Marty,
> >
> > On Thu, 13 Aug 2020 at 13:35, Alper Nebi Yasak <alpernebiyasak at gmail.com> wrote:
> > >
> > > Hi Simon, Marty,
> > >
> > > I'm interested in getting U-Boot to work with Kevin as well, but don't
> > > have a Servo (or the willingness to open up the case yet), so I've been
> > > trying to boot from depthcharge as in README.chromium-chainload.
> > >
> > > I don't have a way to see serial output and I see no other signs of
> > > life. Can you give me a tested configuration that immediately powers-off
> > > or reboots a Kevin so I can confirm what I'm doing works on the
> > > chainloading side? I mean I can boot Linux, but trying the same with
> > > U-Boot just gives me a blank screen even after accounting for a lot of
> > > things.
> > >
> > > Meanwhile, I've wrote some code to automate making depthcharge partition
> > > images, and to enable the display on Kevin (and perhaps Bob). Since I
> > > don't know if chainloading works, I don't know if these are broken or
> > > not either. I'm unsure about sending untested patches to the list, so I
> > > put them up here if you want to take a look (and maybe test/fix them?):
> > >
> > > https://github.com/alpernebbi/u-boot/tree/rk3399-gru-kevin/wip
> > >
> > > They're not really things that'd make a non-booting Kevin boot, though.
> > > I hope at least some of it can be useful in some way.
> >
> > I am just replying here as you asked for some details on IRC. What
> > details do you need?
> >
> Well, if its possible to actually do openocd/etc on the AP using a
> servo, I'd like to know how. All the documentation I could find is about
> using openocd to flash the EC, not debug the AP.

OK...in my case I attached a ARM DSTREAM JTAG unit to the 20-pin
connector on the servo 2 board. I was then able to connect and debug
U-Boot and linux. This was on a snow (Samsung exynos) so not the same
SoC, but it might work. I can't recall the clock speed, but it
certainly was slower than 200MHz.

This has some info:

https://elinux.org/images/7/7f/Manderson5.pdf

Here are the instructions I wrote, from the history as they have been
removed from the page, being so out of date!

https://sites.google.com/a/google.com/chromeos/system/app/pages/admin/compare?wuid=wuid:gx:300e7216a93e8403&rev1=29

> > I was intending to try out a kevin if I have one. I will add that to my list.

Regards,
Simon