Dan Malek wrote: > As I have explained before, the IMMR and possibly a few other > board control registers must have physical addresses above > 0x80000000. This is because the early kernel initialization > will map these 1:1 virtual to physical. They are needed before > the kernel VM allocator has been initialized. If they are > below this address, they clash with the user virtual space, > so depending upon the loading of programs and libraries, you > left a big virtual hole into kernel managed hardware.
My IMMR is 0xFF000000. I basically followed the BSE-IP stuff when I ported linuxppc to our own board. This is above 0x80000000 so this should be fine, but I do have some peripherals (LEDs, etc) mapped to memory lower than 0x8000000 (eg 0x20000000). Is this good or bad ? Would it be better if I memory mapped everything above 0x80000000 (except DRAM of course) ? Brendan Simon. ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
