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Re: MMU enabling for IXP425
- From: Mark Salter <msalter at redhat dot com>
- To: Raghu <raghu_dk at yahoo dot com>
- Cc: ecos <ecos-devel at sources dot redhat dot com>
- Date: Wed, 26 Jan 2005 08:38:51 -0500
- Subject: Re: MMU enabling for IXP425
- References: <20050126112622.68462.qmail@web40427.mail.yahoo.com>
On Wed, 2005-01-26 at 03:26 -0800, Raghu wrote:
> Hi,
> I have a IXP425 based custom board, and trying to
> enable MMU in Redboot ROM monitor. I have 64 Mb SDRAM.
> And set following mem map in "hal_platform_extras.h"
>
> VA PA XCB Size Desc
> 0x00000000 0x00000000 010 64Mb SDRAM ( Cached )
> 0x10000000 0x10000000 010 64Mb SDRAM ( Alias )
> 0x20000000 0x00000000 000 64Mb SDRAM ( UnCached )
> Reset as in IXDP425 !
...
> But in the "hal_platform_setup.h" file on enabling the
> DCache at instruction, "mrc p15, 0, r0, c1, c0, 0" is
> get a "Prefetch Abort".
>
...
> Any clues ?
> Also how are the FL_SECTION_ENTRY for PCI, MISC
> created. The macro uses on .word everytime.
>
I would look carefully at the page table. The way the table is
constructed in hal_platform_extras.h is error prone. The latest
code in cvs uses a less error prone method. I suspect that there
is no mapping for the flash and the first i-fetch after mmu is
enabled is causing the prefetch abort.
The pagetable entries for PCI and other IO areas should be there
in hal_platform_extras.h
--Mark