From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Roese Date: Tue, 3 May 2011 15:07:40 +0200 Subject: [U-Boot] PPC405EX CHIP_21 erratum In-Reply-To: <4DBF25DA.7040806@harris.com> References: <4DBF1F33.4040101@harris.com> <4DBF25DA.7040806@harris.com> Message-ID: <201105031507.41274.sr@denx.de> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Monday 02 May 2011 23:44:58 Steven A. Falco wrote: > I have not been able to find a way to distinguish a power-up versus a > reboot. So for now, I've implemented the AMCC bug fix more or less as > written. To do it right, we'd have to add entries in every U-Boot config > file for the 405 EX/EXr to definitively specify the CPU type expected, and > to put the list of allowed PVRs in the code. > > This means that the PVR is essentially useless to distinguish between the > EX and EXr, because we have seen one misbehaving EX report as an EXr! > If the PVR had been garbage, we could maybe use it, but reporting "wrong > yet legal" values makes it worthless. > > All our boards use the EX, so we are able to live with this, but I realize > it is not a solution for the larger community. That is why I have not > proposed a definitive patch. I see. Thanks for the explanation. IMHO, it would be best to provide a default list of PVR's that are allowed/correct for 405EX(r). And this list can be overridden by a board specific version (as needed in your case). Not sure how to handle this elegantly in assembler though. We might move this to cpu_init_f(). This is the first C function called via start.S. It already handles similar issues for some 4xx SoC variants (reconfigure_pll()) which require a system reboot. What do you think? Would you be able to prepare a patch with such a CHIP_21 fix? Cheers, Stefan -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-0 Fax: (+49)-8142-66989-80 Email: office at denx.de