Accessing DDR DCR registers in init_mem - PMC RM9000

Sean Parker <supinlick@xxxxxxxxx> · Mon, 14 Jul 2008 06:55:42 -0700 (PDT)

 Hello - 

   We're trying to determine dynamically the DDR DCR
 register values from within setup.c, init_mem(), so that we
 can remove the hard-coded 256MB RAM size (and not rely on
 cmd-line args) From documentation I've read (not evry
 clear for a MIPS newbie) it appears I need to setup a TLB
 entry to access phys mem above 0x80000000. (PMON already
 sets up a range for Compact Flash)

   I setup a TLB entry for that region ( 0xFF080000, making
 3 total entries setup in PMON) but I still get an exception
 in setup.c when I try to read the DCR reg.

   Is it as simple as setting up a TLB entry? I can't
 find examples for how to access registeres in various
 segments of physical memory (in kernel mode) does anyone
 know of a good resource for that kind of stuff?

   Any suggestions?

   Thanks
    Sean