Re: Problem in getting kernel vritual address

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>> Hello All,
>>
>> I have a board MPC 8540 ported with ppc Linux and U-boot. U-boot is going to intialize the memory map, like mapping 0x00000000 to SDRAM interface and 0xe0000000 to pci interface. so when we write at 0xe0000000 , the data will go through the pci.
>> Assuming that whatever the memory map done by U-boot is carried over to the Linux, I wrote
>>
>> virtual_address = __va(0xfdf00000) to get the virtual address for CCSRBAR , which contains fdf00000 at offset zero.(It contains it's address at the offset zero from the CCSRBAR).
>>
>> If I dereference the virtual_address( *virtual_address = fdf00000)
>> it should contain the same address. But when i tried this , it result in segmentation fault. pls give me any clue.


Why don't you check the source code? There must be a structure which
maps the whole register space (like immap). (it might be called immap.h or something ...) You will have to get that
structure address and dereference the corresponding member to access the
register. IMO one cannot dereference access registers like have done.


HTH.
om.

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