porting for Novena and other new iMX6 boards

[Bernd Walter]

I do own a few iMX6 boards, which are not directly supported by
FreeBSD.
My latest addition is one of those famous Novena boards.

The filesystem on the supplied micro-SD card lists:
[57]cicely13# ls -al
total 7464
drwxr-xr-x   1 root  wheel    16384 Jan  1  1980 .
drwxr-xr-x  37 root  wheel     1024 Dec 13 10:36 ..
-rwxr-xr-x   1 root  wheel    39835 Nov 14 22:28 novena.dtb
-rwxr-xr-x   1 root  wheel    39835 Nov 14 22:29 novena.recovery.dtb
-rwxr-xr-x   1 root  wheel   304876 Nov 14 22:27 u-boot.img
-rwxr-xr-x   1 root  wheel    35840 Nov 14 22:27 u-boot.spl
-rwxr-xr-x   1 root  wheel  3598728 Nov 14 22:29 zImage.recovery
-rwxr-xr-x   1 root  wheel  3598728 Nov 14 22:28 zimage

I think I can handle setting up a FreeBSD kernel with the required
IO specifications as long as those definitions are compiled into
the kernel.
However I'm unsure about the whole uboot story and could use some help.
As far as I know we do need special features from that uboot to
boot a FreeBSD kernel with loader support.

-- 
B.Walter <bernd at bwct.de> http://www.bwct.de
Modbus/TCP Ethernet I/O Baugruppen, ARM basierte FreeBSD Rechner uvm.