Problem in writing to physical memory through a module

atif_shabir · 10-22-2009, 10:10 AM

Hello

I want to write data to a physical address of my choice. For it I am writing a driver (just like parallel port driver). In my driver code I use check_region() function to check whether the address is free or not. Then I use request_region() to reserve that address for my driver. When the driver is loaded using insmod, it is loaded successfully (i-e the address is reserved for my driver). The corresponding /dev/<filename> opens successfully but when I write to the /dev/<filename>, I get segmentation fault.

Where can the problem be?

If an address has been reserved for me, I should be able to write on it. But I can not write.

Kindly give me some clue.

Regards

Atif Shabir

anishakaul · 11-19-2009, 04:06 AM

Kindly post some code for us to look at !

cladisch · 11-19-2009, 04:48 AM

The physical address space and the kernel's address space are not identical.
You did not mention that you mapped your physical address, so I guess you didn't.