Re: [OpenOCD-devel] QCA IPQ8064

[Andreas F. <and...@gm...>]

Hi there!

On Mon, Aug 22, 2016 at 5:43 AM, J Mo <jm...@jm...> wrote:

>
> The board, in addition to the IPQ8064, has 2x QCA9980 802.11 radios, a
> QCA8337 ethernet switch, and a Spansion S34MS02G200BHI000 256MB SLC NAND
> flash. No telling what's on the JTAG line though.
>
> I bought a TIAO TUMPA adapter board since it looked OpenOCD compatible
> and handles the 1.8v signal levels. I've already hooked it up, built
> OpenOCD from source, and tried autoprobing, but I'm not finding anything.
>
> It looks like OpenOCD can't currently handle working with this SoC.
> Signal levels on the JTAG port look good and LEDs on the board indicate
> debug activity, but I'm not finding anything.
>

Not finding anything as in the JTAG chain scan says "all ones" or something
similar, no TAPs detected? Then nothing you do with the target
configuration will help anything, the problem is on a lower level. Probably
the board needs something extra to actually enable JTAG. On some of the
pictures it looks like R33 is not mounted and that it disconnects the nTRST
signal between the connector and the target (the pull-up being on the
connector side, so you'll measure the correct voltage). I'd take a guess
and say that nTRST pulled down on the target side of R33 to disable JTAG.


> I googled around and I think the closest SoC people have been working
> with is the apq8064.
>
> I think this patch might the reason I'm held back right now:
> http://openocd.zylin.com/#/c/3124/
>
> I will look into merging in some of those changes here soon and see if I
> can't autoprobe anything after that.
>
>
There's no autoprobing going on that will be helped by that patch. It might
be needed as soon as you actually discover and set up a target though.


> Ideally, I would like to be able to write to the NAND flash, but if I
> could load u-boot into RAM and boot from it, that would be great too.
> Along the way, I'd like to learn as much as I can.
>

Loading a RAM u-boot is probably the easiest way forward if you primarily
want to get the board up again. If it's not already supported, getting that
combination of flash and target working in OpenOCD could be a lot of work.

/Andreas