From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Roese Date: Wed, 4 Jul 2007 14:37:39 +0200 Subject: [U-Boot-Users] U-Boot-NG ? In-Reply-To: <20070704122621.GM3361@leda.ptxnet.pengutronix.de> References: <20070703175856.GB8839@pengutronix.de> <200707041356.32051.sr@denx.de> <20070704122621.GM3361@leda.ptxnet.pengutronix.de> Message-ID: <200707041437.39449.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 Wednesday 04 July 2007, Sascha Hauer wrote: > > > I once wondered why it takes _so_ long to get a prompt on my MPC5200 > > > board. The solution was simple: U-Boot was busy reading the environment > > > from EEPROM several times. > > > > Yes. That is one of the reasons, why it is strongly discouraged to use > > I2C EEPROM for environment storage. > > I know it is, and it was the customers decision to so, but I think using > an I2C eeprom _should_ be no problem. It's just like any other memory > device. ACK. > > If no output on the serial console always means: "problem with memory", > > than this would be an easy indication for SDRAM problems. But I have seen > > lots of other errors, that lead to a hangup in the very early boot stage. > > Most of the time *before* SDRAM is initialized. > > Don't have the boards where DIMMs can be changed some kind of beeper or > LED telling you about memory problems? Some have some don't. > > Don't get me wrong. I generally like this 2 stage approach. For example > > it fits the NAND booting support (see nand_spl/*) where a small (4k on > > 4xx) first stage loader is needed. I'm just a little hesitant about > > dropping the full featured printf in early boot stages. > > I think we have little choice if we want 4k boot block support, early > console output _and_ a maintainable tree. Yes. The current nand_spl implementation has no serial output at all. And when problems occurred (which has already happened and *not* in the SDRAM init process, just CPU setup which can be quite complicated and can not be deferred to after SDRAM init), I would have really liked this output. I once had a version with such a hardcoded serial output, but dropped it after everything was working. I should have kept it in the source via some "debug" functions. Best regards, 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 =====================================================================