RE: Power On Self Test and testing memory

["Lyle Bainbridge" <lyle@zevion.com>]

Hi,

I used the same strategy, but had similar issues.
So I just skip the first couple of 1000 bytes.
I'd like to find out why too.

Also, memory wraps.  If I have 32MB of RAM @ 0x80000000,
then run the memory test in non-existent memory from
0x82000000 to 0x83ffffff it appears to reference 0x80000000
to 0x81ffffff.  Can this be made to fail?

Lyle


> -----Original Message-----
> From: linux-mips-bounce@linux-mips.org 
> [mailto:linux-mips-bounce@linux-mips.org] On Behalf Of Jeff Baitis
> Sent: Wednesday, May 14, 2003 5:27 PM
> To: linux-mips@linux-mips.org
> Subject: Power On Self Test and testing memory
> 
> 
> Hi all:
> 
> I implemented memory tests in my bootloader code for the 
> AU1500. I'm trying to figure out why Linux boots when loaded 
> into cached KSEG0 (0x 80c0 0000), but my memory test FAILS 
> for this same region.
> 
> (pretty backwards huh? get linux booting, then write memory tests!)
> 
> 
> I start by writing 0x5555 5555 to all of uncached memory, 
> reading it back, and I write 0xAAAA AAAA to all of uncached 
> memory and read it back.
> 
> This works great.
> 
> Next, I try to write 0x5555 5555 to cached KSEG0 memory, and 
> it fails at addr 0x8000FE50. But Linux boots!
> 
> I'm not issuing SYNC commands when writing to cached memory; 
> could this be the problem?
> 
> We've exhaustively verified the memory burst parameters, etc. 
> They look good.
> 
> Thank you in advance for your ideas!
> 
> Regards,
> Jeff
> 
> -- 
>          Jeffrey Baitis - Associate Software Engineer
> 
>                     Evolution Robotics, Inc.
>                      130 West Union Street
>                        Pasadena CA 91103
> 
>  tel: 626.535.2776  |  fax: 626.535.2777  |  baitisj@evolution.com 
>