> I want to try to port Linux to a new StrongArm platform. However, I am
> not even sure if any driver currently works (e.g. serial, screen,
> whatever). And not sure if the bootloader of the device will start my
> Linux kernel.
>
> How did anyone of you manage to get over this obstacle? Did you write
> code that just outputs info on some GPIO pins? Has someone written a
> paper on "How I managed to port Linux to ... platform?". Or do you have
> pointers to a better mailing list where I could ask around?
(I'm assuming you mean the 1100/1110)
As the UARTs are built in, just get the hardware working a step at a time -
firstly, remember to go into 32-bit CPU mode so you can actually use the
onboard hardware - configure the uart, get a few characters out of it, that
sort of thing, the bring up the RAM. To do this originally on the empeg we
had flash in a socket, so the bootloader could be tweaked - it only took a
couple of cycles before the reflasher was running and we didn't need the
socket anymore.
Resorting to flashing LEDs on GPIO lines is rarely necessary :)
This is a good socket to start with, if you need one (TSOP-48)
http://www.meritec.com/Pages/products/sockets/tsop.html
They're a pain to solder down, but are only about $5 (or get a couple of
samples for free...)
The other way is to use an existing bootloader, like blob. The main thing
you want to do in your bootloader is intialise GPIOs (directions and
values), get RAM running and allow reflashing - blob does all this, but
we've stuck with the original bootloader I wrote years ago, even on
non-strongarm platforms.
After that point, linux pretty much runs out of the box on the SA11x0 - just
copy the vmlinux (I'd get this working first, the zImage stuff has other
bits like UART access which may need tweaking) to the right point in memory,
setup r0/r1, and jump to it. The SA's hardware is pretty much all supported
by linux, it's just a question of tailoring it (eg, screen size & timings
for the LCD). It's amazing when you just twiddle some bits, recompile, and
all of a sudden there's a penguin logo on the screen!
Hugo
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