Hey Dan, On Tue, 30 Nov 1999, Dan Malek wrote:
> Mark S. Mathews wrote: > > We've been working with the embedded 2.2.13 kernel on an RPX-Lite CW with > > a XPC823ZT66A processor running at the 50MHz/8MHz setting. > > > It's not only the RPX Lite.....I have a variety of 8xx boards > and when I have trouble like this with a particular card, it > occurs in all of the boards. 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 (?) > > > > ............ but our > > accesses to the common memory regions of the card are twitchy. > > > Same thing I have seen. The I/O and attribute regions seem > to work OK, but memory regions don't.....on more than one > type of card. 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. > > .....but eventually we wind up with a machine-check. > > Which points to some kind of bus timing or protocol problem. We've been running _lots_ of experiments with the timing settings. So far 3,10,6 seems to work best....but it still fails. > > runs well on the x86, our PowerBook, and on a different 860 based platform > > (non-Linux, no MMU) so we're fairly confident it isn't the code. > > Well now, that's interesting (the no MMU, not the non-Linux > part :-). With the MMU disabled, the accesses behave as guarded. I've seen the 'guarded' thing around in the sources, but I'm not sure what it's all about. Guess I should look. ;-) > This is something I have not properly implemented on the 8xx, > and with my somewhat sloppy use of eieio() and synchronization, > I am always waiting for this to come back and haunt me. Notice > how I buried this important fact in this paragraph. I will now > properly implement this (yet tonight). Tell me the kernel version > you are using and I will send some updates for your testing. embedded kernel 2.2.13 > How does someone (like me :-) determine what a PCMCIA interface > in something like a PowerBook uses for bus timing? I'm not really sure. Have to ask David, it's probably buried in pcmcia-cs somewhere. > > One specific question...when setting up the PCMCIA bus timings, the 823 > > book lists the settings in units of "clock cycles". Which clock? > > It is the CLKOUT (system/bus) clock. On the 66MHz processor, > this better be 33 MHz (processor clock / 2). For 50 MHz or > less, the CLKOUT is the processor clock. BIG help! Thanks a million. We'll keep trying and let you know. -Mark 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/
