Dear St?phane,
Yes i remember your mail about /dev/mem access. But, I never succeed to
read or write physical memory with reliability so i wrote a driver and use
ioremap inside intead of mmap (before i put all the needed memory on IO
memory with the boot command "mem=xM" and then it works. So, i think i have
some problems with "mmap" :-).
I think my .../char/mem.c is OK for mmap support.
Why is it necessary to use size+ofs_addr for size and page_addr instead of
physaddr, i thought mmap( ) do it itself ?
Thank you for your help.
Kenavo.
Sophie.
"Fillod Stephane"
<stephane.fillod at th Pour : <scarayol at
assystembrime.com>
omson.net> cc : <linuxppc-embedded at
ozlabs.org>
Objet : RE: R?f. : Re: Read
in /dev/port with Segmentation Fault
09/06/05 11:35
Sophie CARAYOL wrote:
>Another question, if i use mmap to map physical addresses of I/O
registers,
>could i dereference the pointer on virtual adresse to access data or
should
>i use read/write on the file descriptor ?
Yes, you can dereference the pointer.
Don't you remember my past mail?
>From the Denx's FAQ (TFQ hits the list monthly) for accessing memory bus:
http://www.denx.de/twiki/bin/view/PPCEmbedded/DeviceDrivers#Section_AccessingPeripheralsFromUserSpace
or shorter: http://tinyurl.com/6c7th
See linux/drivers/char/mem.c to check if mmap support is ok on your arch.
Kenavo
--
St?phane
