From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <38448D2A.E11E4ADF@netx4.com> Date: Tue, 30 Nov 1999 21:51:22 -0500 From: Dan Malek MIME-Version: 1.0 To: "Mark S. Mathews" CC: linuxppc-embedded@lists.linuxppc.org Subject: Re: RPXLite 823 PCMCIA troubles References: Content-Type: text/plain; charset=us-ascii Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: Mark S. Mathews wrote: > > Howdy Folks, > > 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. > ............ 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. > .....but eventually we wind up with a machine-check. Which points to some kind of bus timing or protocol problem. > 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. 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. How does someone (like me :-) determine what a PCMCIA interface in something like a PowerBook uses for bus timing? > 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. -- Dan ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/