SMP support for ZEDBOARD
Thomas Skibo
ThomasSkibo at sbcglobal.net
Tue Apr 29 22:40:46 UTC 2014
On 4/29/14, 2:29 PM, Bernd Walter wrote:
>>>>
>>>> Oh - interesting.
>>>> I thought it is just booting from SD and assumed we can use what you
>>>> did for the Zedboard to begin with.
>>>> Wonder why they added a flash chip, when they could have gone without.
>>>> Is this a pin strapping configuration, or something, which can be
>>>> changed?
It looks like it can't boot (directly) from the SD card because it is
attached to SDIO1 and not SDIO0. I guess it can only boot from SDIO0
and SDIO0 isn't available if you have two USB interfaces and Ethernet.
Take a look at the MIO-at-a-Glance Table in the Zynq manual (page 52 in
my copy). Hence, the need to boot from the QSPI flash.
>>
>> Did I get it right, that the ROMcode loades the FSBL from either JTAG
>> or flash.
>> The FSBL then could load u-boot from whatever it supports, but on
>> the parallella they load u-boot from QSPI, so it has to be updated?
>> I do have a JTAG available, according to the parallella schematics
>> however it is setup via solder pull-up vs pull-down resistor.
>> I also have a hot air soldering station, but still not nice.
>> I also would have to lock up where the JTAG is - probably on one of the
>> Samtec connectors :-(
>
> Ok - JTAG is on the SAMTEC.
> Bootmode as well - the resistor mode pin was cascaded JTAG vs dedicated.
> No soldering, but needs some kind of breakout board.
> I remember having seen 0.1" breakout somewhere already, not sure if
> it's possible to get one of them.
> A JTAG defintively should be reachable in case it's bricked.
>
It should be possible to create a u-boot that will work with either
FreeBSD or Linux, program it once, and be done. Xilinx's latest u-boot
release can do this because it has CONFIG_API set and allows a uEnv.txt
file to customize the boot environment. This is how I can boot FreeBSD
with an unmodified u-boot. I think I may already have a config built
that might work.
Then, it's a matter of reprogramming the QSPI flash. This describes how
to program the QSPI flash presumably even if it's blank:
https://github.com/parallella/parallella-hw/tree/master/boards/parallella-I/firmware
But if the flash is already programmed, I think it might be possible to
stop it at a u-boot prompt, skip to step 9 and program the new image.
Just hope there's no power failure while rewriting!
--
--------
Thomas Skibo
ThomasSkibo at sbcglobal.net
More information about the freebsd-arm
mailing list