Using bestcomm in an external module (MPC5200B to be exact)

Trueskew trueskew at gmail.com
Mon Jun 19 17:28:27 EST 2006


I should've let you all know, I'm more of a 2.4 person than a 2.6 person.
So I read what I could on 2.6 difference with 2.4, and it looked like my
easiest choice was to modify the bestcomm code to export a couple tables and
its API functions.  I found that kallsyms has almost all of the functions I
needed to resolve (with 'T' next to them), but they were still not working.
I added EXPORT_MODULE(TaskBDReset) and similar declarations in the bestcomm
api code, but that still didn't do the trick for me.  So what is the trick?
I think I'm on the right track, I can insmod a module that my driver needs,
see kallsyms get updated, and access the functions directly in my driver.  I
hope I'm close to doing something similar with the bestcomm functions, can
anyone offer me some advice on what else I need to do?

Thanks.

________________________________

From: Trueskew [mailto:trueskew at gmail.com] 
Sent: Friday, June 16, 2006 9:47 PM
To: 'linuxppc-embedded at ozlabs.org'
Subject: Using bestcomm in an external module (MPC5200B to be exact)


I'm writing a driver for a TI codec attached to the MPC5200B PSC3 codec
lines on a Lite5200b.  It's an external module, and I'd like to use Bestcomm
with it.  I've already tried a bunch of horrible things to get it to work.
I could say it's close, but by close I mean the FEC still runs, my stuff
doesn't.  
 
1. Can the Bestcomm I/F be used by an external module, or is the module
required to be built in if built-in drivers use Bestcomm?  TasksInitAPI (no
so bad) and TasksLoadImage (yeah, bad) aren't really supposed to be called
more than once from what I've read, and the kernel loads them for ethernet
and ATA (no disk in my system if that matters).  
 
2. If it can be used by an external module, how would I do it?  I've tried
compiling the source into my module and replicating the initialization the
kernel does in addition to my own stuff.  It's not too bad, though I don't
get any interrupts yet.
 
The LTIB from Freescale includes AIC23 and AC97 drivers that use Bestcomm.
I built my kernel with them set as modules, and they had the same unresolved
problems that my driver has on insmod, so I'm pessimistic.  If someone could
put me out of my misery one way or another, I'd appreciate it.
 
Thanks.
Sal




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