On Wed, 2003-05-14 at 15:56, Lyle Bainbridge wrote: > 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? Write something other than 5555 5555 and you'll catch the "problem". If you write the address of the memory location or in the inverse of the address, you'll catch the wrap around. Pete > 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 > > > > >
