Thanks Brian,
This suggestion is most definitely an important note for future reference. Unfortunately, this card only supports 8-bit transfers and the troubles were especially bad in the common memory region. Thanks again, -Mark On Thu, 2 Dec 1999, Brian Kuschak wrote: > 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 > > > > > > > > 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/
