From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Littell Date: Wed, 23 Apr 2008 21:17:32 -0500 Subject: [U-Boot-Users] AMCC PPC440EPx/sequoia stability question... In-Reply-To: <200804231449.24746.sr@denx.de> References: <480EADF4.2020706@verizon.net> <200804231449.24746.sr@denx.de> Message-ID: <480FEDBC.2010401@verizon.net> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Stefan Roese wrote: > On Wednesday 23 April 2008, Dave Littell wrote: >> I'm working on an AMCC PPC440EPx-based platform that's similar to the >> Sequoia. The board runs pretty well, but occasionally takes exceptions >> both in U-Boot and while running Linux. The exceptions vary from >> Illegal Instructions to FP Unavailable to FP Unimplemented to ITLB and >> DTLB Errors, to DSI, etc., which made us believe there's a problem with >> SDRAM. > > Yes, this is my first idea too. Almost every time such "random" errors are > seen, SDRAM setup/initialization is the cause for it. > >> Sometimes there are simple hard lockups from which even the JTAG >> can't regain control. However, the SDRAM physical/electrical and DDR >> Controller configurations have been investigated in detail (and some >> corrections made) with no resulting improvement in the exception behavior. > > Is the SDRAM termination similar to the one used on Sequoia too? Are you using > soldered chips and not DIMM modules? Is ECC available? > Termination: very likely - they stayed very close to Sequoia, but I'll ask. We're using soldered chips and there's no ECC. >> We see problems primarily at 667 MHz but have noted some issues at 533 >> MHz as well. Some boards seem particularly susceptible to this while >> others rarely (if ever) exhibit the problem. >> >> At this point all possibilities are on the table and I'm looking for any >> input from anyone with experience (good, bad, or whatever) with this >> processor and/or designs similar to the Sequoia. > > If you scan the U-Boot mailing list for 440EPx/Denali DDR2 problems, you will > most likely find some references. > Will do, thanks for the pointer. > Please note that I recently introduced a CFG_MEM_TOP_HIDE option for the > 440EPx CHIP 11 errata. I suggest you take a look at this too and see if this > changes your behavior. > I remember this - PPC440EPx Revision A errata CHIP_11, right? Thanks, Dave