RE: problem in accessing register for at91rm9200

["Prakash" <Prakash.Kamliya@xxxxxxxxxxxxxxxxx>]

Hi Manila,

You can not directly access the Register address using absolute addressing
while working on Linux. You need virtual address. 

First you will have to convert absolute address to virtual address and then
you can write and read values on this address.

I have used ioremap() function in my driver code to convert absolute address
to virtual address. 

You can visit 

http://os.inf.tu-dresden.de/l4env/doc/html/dde_linux/group__mod__res.html

and Google for ioremap

Bye
Prakash

-----Original Message-----
From: linux-arm-bounces@xxxxxxxxxxxxxxxxxxxxxx
[mailto:linux-arm-bounces@xxxxxxxxxxxxxxxxxxxxxx] On Behalf Of Manila Goel
Sent: Thursday, June 26, 2008 1:44 PM
To: linux-arm@xxxxxxxxxxxxxxxxxxxxxx
Subject: problem in accessing register for at91rm9200

hi everyone
i m using the atmel at91rm9200 board on which vender has ported linux 2.6.14
and given a arm-linux-gnu-gcc compiler for cross compilation. so my question
is i m accessing the pio registers like PIOB_PDSR to know the status.i m
accessing it by giving the absolute address (0xfffff63c) of the register and
getting the segmentation fault.so please any one tell me is this the right
method to do the same or is their any other method to accessing the
registers.

thanks
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