[ELDK] Kernel access of bad area

Stefano Babic sbabic at denx.de
Thu Sep 9 19:10:12 CEST 2010

Luigi Rizzi wrote:
> Hello,


> on my system I'm using a TQM885D module with U-boot 1.3.0-rc2 and
> Linux 2.4.25 (DENX ELDK 3.1.1).

Really very old...

> I connected to  this module an
> external SRAM (actually a dual port SRAM that act as interface with
> another system...) and than I configured in U-boot the chip select
> for this memory. I mapped the Memory starting from 0x80000000.

How do you mapped it ? Which ioremap() function do you use it ?

> When I try to access this memory everything seem to works fine till
> address 0x8000FFFF. Above this address kernel displays this error:
> Oops: Kernel access of bad area, Sig: 11

The SRAM is not mapped by MMU. As I see in code, the address is already
used for PCI and only 64KB are mapped. It is exactly the RAM you can see.

Best regards,
Stefano Babic

DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
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