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commands).

In my driver I tried to ioremap() this address and any attempt to access
led to crash, same as with mmap().

When, following your suggestion, I used address 0x1ea00000 and
ioremap64(), crashes disappeared!

I even can write, but when I read data back I see least significant byte
of each 16 bits word only (bus is configured 16 bits width).=20

What can it be?

Thanks,

Leonid.=20

-----Original Message-----
From: Josh Boyer [mailto:jwboyer at gmail.com]
Sent: Tuesday, April 01, 2008 6:44 PM
To: Leonid
Cc: linuxppc-embedded at ozlabs.org
Subject: Re: Access physical memory via mmap() on ppc440epx.

On Tue, 2008-04-01 at 14:12 -0700, Leonid wrote:
> Hi:
>=20
> I am trying to read from NOR flash, located on address 0xfc000000, on
my

It's at 0x1fc000000 IIRC.

> TLB entries look strange though. That what it was on u-boot stage:
>=20
> 440EPx>tlb 0 10
> IDX TID      EPN  SIZE VTS          RPN   USER WIMGE USRSVC
>  0 : 00 40000000 256MB V0 -> 0_00000000 U:0000 -I-G- XWRXWR
>  1 : 00 00000000 256MB V0 -> 0_00000000 U:0000 -I-G- XWRXWR
>  2 : 00 c0000000 256MB V0 -> 1_c0000000 U:0000 -I-G- XWRXWR
>  3 : 00 f0000000 256MB V0 -> 1_f0000000 U:0000 WI-G- XWRXWR

See.  Virtual is 0xf0000000, physical is 0x1f0000000.

> On Linux stage it looks rather different:

I don't even see your entry in here.  Likely because the TLB is small
and it's gone by the time you do the dump

> Probably under MMU it should look this way? How to use mmap() then?

Try mmap64 on the real physical address and see if that helps.

josh

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