Mark, One thing to note about PCMCIA I/O region accesses on the 823...
If the access is to a 16-bit port, the PCMCIA controller needs to see an acknowledgement from the card on the IOIS16_B pin. However when the processor is configured for debugging (full trace, etc) this pin is unavailable. It's muxed with some other debug function (VFLS, I think?). Check your settings in the SIUMCR register. If the core never gets this acknowledge on the 16 bit access, it might generate a bus error, which would show up as a machine check. There are only two solutions for this hardware shortcoming. Either setup the SIUMCR to give up your trace capability (which isn't very useful w/ virtual memory anyway), or don't do 16-bit accesses in PCMCIA I/O space. Hope that helps. -Brian Kuschak --- "Mark S. Mathews" <mark at absoval.com> wrote: > > Howdy Folks, > > Ok, the wlan PCMCIA card is working....but only > after an ugly hack. > Basically, I modified > the MachineCheck function to ignore the exception > (just return) if the > faulting address (contents of DAR) falls in the > iomapped range we've > established for the PCMCIA card. > > Any opinions on our solution? > > I'd still like to know what's causing these > exceptions, but that's for > another day. > > -Mark > > On Tue, 30 Nov 1999, Dan Malek wrote: > > > > > Mark S. Mathews wrote: > > > > > > > Hmmmm. The way ours "works for awhile", I'm > wondering if there's a > > > problem w/ the way the 8xx is handling the WAIT# > when the MMU is enabled > > > (?) > > > > Shouldn't be the problem. The MMU appears (on > block diagrams > > anyway :-) to be far enough removed from the > memory controller > > for this to happen. > > > > > > > This is good to know. Our card supports I/O or > memory access to the > > > shared memory. We'll shift over to the I/O and > try that. > > > > The version I have running on my PowerBook only > uses I/O..... > > or am I mistaken? > > > > > > > We've been running _lots_ of experiments with > the timing settings. So far > > > 3,10,6 seems to work best....but it still fails. > > > > Thanks. I'll keep those numbers around.....there > are others > > I would rather see.....:-). > > > > > > > I've seen the 'guarded' thing around in the > sources, but I'm not sure what > > > it's all about. Guess I should look. ;-) > > > > I just fixed it. I'll send it to you privately as > well as > > post it on the ppc.kernel.org server. I hope it > corrects > > something. > > > > > > > > -- Dan > > > > > Mark S. Mathews > > AbsoluteValue Software Web: > http://www.absoval.com > P.O. Box 941149 e-mail: mark at absoval.com > Maitland, FL 32794-1149 Phone: 407.644.8582 > USA Fax: 407.539.1294 > > > ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
