[openfirmware] On Raspberry Pi

[James Cameron]

On Fri, Sep 14, 2012 at 08:19:28PM +0000, Mark Morgan Lloyd wrote:
> Is it possible to put OpenFirmware on an SD card and use it to boot
> off e.g. a USB-attached mass storage device or using TFTP over a
> LAN?

I've now a Raspberry Pi (B).

The armforth.static in the openfirmware repository as of now (r3683)
seems to run:

% cpu/arm/Linux/armforth.static cpu/arm/build/builder.dic
ok bye
% 

and rebuilding it seems to work fine:

% (cd cpu/arm/Linux; make)
...
% cpu/arm/Linux/forth cpu/arm/build/builder.dic
ok bye
% 

and rebuilding the builder seems to work fine:

% (cd cpu/arm/build; make)
...
% cpu/arm/Linux/forth cpu/arm/build/basefw.dic
ok no-page to-file test words
ok bye
% 

So user-mode is probably okay, and a useful tool.

It is said [1] that the SoC loads various files and runs them on the
(closed) GPU.  It then loads kernel.img and runs it on the ARM.

% file /boot/kernel.img
kernel.img: Linux kernel ARM boot executable zImage (little-endian)
% 

I'm not planning a port, but I thought I'd mention what I've found so
far, in case anybody is interested.  The porting would be drivers for
serial, SD, ethernet, and USB, possibly using the kernel sources as
reference, given that there's very little data available.

References:

1.  http://www.raspberrypi.org/phpBB3/viewtopic.php?f=29&t=10727

-- 
James Cameron
http://quozl.linux.org.au/