[openfirmware] Porting OFW to custom hardware

R&D4 r&d4 at dave-tech.it
Fri May 23 18:51:08 CEST 2008


Dear Mitch,

Mitch Bradley wrote:
> R&D4 wrote:
>> Is this correct?
> 
> That's a good start.

Thanks! ;-)

>> Of couse, it's a bit hard for me to figure out, for example, where to 
>> look for some basic initialization (e.g. PLL, SDRAM, memory mapping).
> 
> I assume you are using the version that I checked in yesterday, that 
> removes the olpc dependencies from the lxdevel build.  If not, switch to 
> that version.  It will be much easier to work with.

Yes, I checkout the latest release (from the dwmw2's git repository 
here: http://git.infradead.org/?p=openfirmware.git;a=summary).
This is easier then svn for us because we already use git internally.

> The PLL init is in "rmstart.fth" - that is "real mode start", which is 
> [snip]

Thank you very much for this precious informations!
Now I'm able to:
* enable serial port
* boot OFW on our custom board

I was also able to remove keyboard initialization from startup and also 
able to start debugging some simple Forth programs.

There are still some problems (IMHO in my PLL or SDRAM inits) because I 
have some weird and random problem like:

+cs
Type 'i' to interrupt stand-init sequence
ff04cfc0  Page Fault
ok

or

Type 'i' to interrupt stand-init sequence

Welcome to Dave Neptune
Interactive boot
Evaluating: master-probe
Inflate size error
ok

When everything goes "well" I got

þ+cs
Type 'i' to interrupt stand-init sequence

Welcome to Dave Neptune
Interactive boot
USB probe
USB2 devices:
USB1 devices:
Failed to set device address: 1
Type any key to interrupt automatic startup
Type 'help' for more information.

ok

and a fully functional shell (but also some random reboots ;-) )

I'll keep you informed about the porting status.

>>
>> AFAIK the "official" documentation is here:
>>
>> http://www.firmworks.com/open_firmware/literature/
>>
>> among these documents is there also a guide for porting OFW or about 
>> OFW "internals"? ("Open Firmware Command Reference" seems the closest 
>> to my needs)
> 
> We did a porting guide for an ARM platform, but we haven't done one for 
> x86.   The command reference has a lot of useful information that is 
> machine independent.  There is also a manual for how to write FCode 
> drivers.  It explains how the device interface works.

Thanks, we will buy them soon!

Best Regards,

-- 

Andrea

DAVE Srl - Electronics System House
e-mail address: r&d4 at dave-tech.it




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