[RM9200] Using data bus and address bus through Linux Kernel

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Hello all,

I would like to use the 16-bit data bus and the 23-bit address bus of the
RM9200, using chip select 4 (cf interface).
I have look over Kernel source code but haven't found some information about
how to do it.
 So i've tried to create a modules to do the following steps:
-init:
   register a char device (This step is ok)
   map the physical address 0x50000000 (as defined by AT91_CF_BASE).
   disable internal pullup for the data bus
   configure chip select timing
-exit:
   unmapping the physical address
   unregister the char device
-write:
   writing 16 bit on the data bus using writeb

The main problem is that during the init step, it seems that an access to
flash memory is done (input/output error in shell, JFFS2 notice in debug).

So I have several question about all of this.
- Is this possible to access to data and address bus such as I/O's even if
SDRAM, Flash memory and so on are connected?
- If data bus can be used through writeb, is there any possibilty for
address bus to be accessed in a similar way?

With kinds of regards,

Frederic
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