Some Success on Zynq/Zybo Boot!

[Emb Aud]

Thanks everyone for the help, and to Thomas Skibo for blazing the trail
with his FreeBSD/Zynq experiments.

I was able to make a little progress today, and I wanted to share my
results.

I don't want to use U-Boot, but for now I am using it for development
purposes.

So, today I made my own build of FreeBSD 10.3 for Arm.  I copied the stock
10.3 ZEDBOARD config to my own ZYBO config file, with the following changes:

22c22,23
< ident         ZEDBOARD
---
> ident         ZYBO
>
91a93,94
> device        rgephy                  # Zybo ethernet
>

I noticed that there are a lot of differences between the 10.3 ZEDBOARD
config and the
"head" ZEDBOARD config.  That's something I need to look into at some point.

Then I compiled everything  using the instructions here:

https://wiki.freebsd.org/FreeBSD/arm/crossbuild

Next, I created an SD-Card image using these instructions:

https://wiki.freebsd.org/FreeBSD/arm/Zedboard

Then I copied all of Skibo's MS-DOS boot files from here:

http://www.skibo.net/zedbsd/  (zybo_extrafiles.tgz)

My image still needed a little tweaking, so I had to:

1. create a /boot/msdos mount point
2. copy Skibo's fstab into my /etc/
3. copy Skibo's rc.conf into my /etc/
4. copy Skibo's board.dtb file into /boot/kernel/

At this point I now have an image that boots FreeBSD 10.3 on the Zybo.

Now that I have a known good kernel and base system install, I can begin
working on my own custom bootloader.

I'm thinking about putting a copy of the kernel on the MS-DOS partition --
or in my case the Xilinx Boot Image File -- where I can have easy access to
it without having to write code to navigate UFS.