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able to access the CS address from u-boot but not from the linux driver

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puneetnepsam

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Hi All,

i have a D flip flop whose data lines are from the PPC controller and it is controlled through one of the chip selects.(CS4).

i have assigned the address on the CS4 and writing the value. From the u-boot it is happening but from the kernel when i try to acess the same area, the result is

Oops: kernel bad access of the area.

Can anyone please tell why this is happening. i m stuck with this problem for last 1 week.

Thanks in Advance
Puneet Gupta
 

puneetnepsam

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i have seen the processor related file.

there its given that the virtual address is 0x80000000

so while accessing the flip flop i have to use the following address??

0x80000000 + my define address

?

Puneet
 

bluehole

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i have seen the processor related file.

there its given that the virtual address is 0x80000000

so while accessing the flip flop i have to use the following address??

0x80000000 + my define address

?

Puneet

How you are mapping the device? on a real physical memory location?
If so is there a method to separate this location from from being managed by memory manager?
if you are allocating a Virtual memory how you are doing it?

If I am not wrong then
1) the IO address should be mapped to a physical memory.
2) the VMM uses a reflection kind of thing like physmem 100x = vmm translate+1000x

have you tried that?
Next look into some legacy driver code, You will get a very good Idea from there.

Hope this helps.
 

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