Re: Read in /dev/port with Segmentation Fault

Dear St=E9phane,

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 I=
O
memory with the boot command "mem=3DxM" 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.




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                    "Fillod Stephane"                                  =
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                    <stephane.fillod@th        Pour :  <scarayol@assyst=
embrime.com>                                                           =
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                    omson.net>                 cc :    <linuxppc-embedd=
ed@ozlabs.org>                                                         =
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                                               Objet :      RE: R=E9f. =
: Re: Read in /dev/port with Segmentation  Fault                       =
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                    09/06/05 11:35                                     =
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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 bu=

s:

http://www.denx.de/twiki/bin/view/PPCEmbedded/DeviceDrivers#Section_Acc=
essingPeripheralsFromUserSpace

or shorter: http://tinyurl.com/6c7th

See linux/drivers/char/mem.c to check if mmap support is ok on your arc=
h.

Kenavo
--
St=E9phane



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