[OpenBIOS] where I'm at with the 440gx and reading nvram

Ronald G. Minnich rminnich at lanl.gov
Mon Jan 24 16:39:28 CET 2000

440gx agpset, page 4-2 has a nice map of the memory. 4-4 shows the
extended bios at 4GB-2M. When I do this: 
 unsigned long l = 0xffe00000;
  unsigned long flashsize = 0x200000;
  void *v;
  v = ioremap_nocache (l, flashsize);
  if (! v) {
        printk("ioremap failed\n");

And I probe that memory I only read 0xff. Bad. It's acting like I'm
getting all 1's due to some control chip rejecting the memory cycle. I'd
be happier with a trap ...

So I check the PIIX4E manual, page 60 (section 4.1.9), it shows that 
register 4f controls what happens with accesses to the high 2MB of the 4GB
region. If you set bit 2 of 4f, requests should be forwarded. This bit is
set on my machine, but no dice anyway. 

Any other thoughts welcome. This is really annoying. We have to get this
working ... 


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