> >>There is one pending problem: the M8xx does not accept > >>access to non present ioports (an exception is triggered), > >>which is quite common while inserting/removing cards. > >> > > Ah yes, I remember this problem from the 68360 days. > > > > This is a matter of how you set up the option register ORx > > <snip> > > for instance, you could turn external ack on once a card > > was inserted. > > > > As I recall, some PCMCIA cards can have VERY long > > cycles in the configuration space, so even the maximum > > number of wait states in ORx may not be sufficient. > > > Unfortunately this does not work on 8xx since the PCMCIA > port is not on a chip select. It's a different peripheral > and always expectes a DTACK to terminate the cycle. > > To get over this problem we need to do something more drastic. > > Take a look at the __do_in_asm macro in include/asm-ppc/io.h. > > Regards > > Pantelis >
You are right, I had forgotten that. I'd also forgotten that PCMCIA uses negative WAIT, which should have a pull-up on it, so there should be no problem with non-existent cards. Another potential problem could be the Bus Monitor Timeout being set too short and generating a TEA before a valid WAIT is released. Mark Chambers
