linuxppc-embedded help needed:kernel access of bad area

[zengshuai at sogou.com]

i writed a led driver for PQ2FADS(a ppc board).
but i can't read/write 0x04500000 where led register addr locate in.
i tested two ways to do that.
first,
p=0x04500000;
*p=0x12;
....
second,
outb(0x12,0x04500000);
...
two ways both didn't work.they had a some wrong:kernel access of bad area.
how can i know which area is bad area or good area?
and what can i do next? thanks.

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