Hello TsiChung. I have added watchdog support in U-Boot for MCF5445x devices using the M54455 EVB platform to test. I can send you a patch if you wish (the timeout is hard coded to 16 secs at the moment)?
However, I am having trouble when U-Boot starts Linux in the case when the watchdog has been enabled in U-Boot. Basically, Linux seems to crash before it gets a chance to print anything on the console - but, control appears to have left U-Boot. Building U-Boot with debug, it displays: ## Transferring control to Linux (at address 40020000) ... BIV Then it's dead after which the watchdog times out and causes a cpu reset. Building U-Boot without debug I get the following: *** Unexpected exception *** Vector Number: 4 Format: 04 Fault Status: 0 PC: 4fdbfdc8 SR: 00002700 SP: 4fd72a64 D0: 00000004 D1: 000003f9 D2: 4fdb4202 D3: 004fa3da D4: 00000000 D5: 4fdc7c8c D6: 122c0034 D7: 4fd82f76 A0: 4033cb98 A1: 4025aa39 A2: 40020000 A3: 4fdbfdc8 A4: 00000000 A5: 4fdc5800 A6: 4fd72afb *** Please Reset Board! *** Then again, the watchdog times out and causes a cpu reset. It definitely appears as though Linux has been started but I cannot tell what has actually happened. I think it's possible that something in the Linux setup has caused (or contributed to) the crash. The problem does not happen if the watchdog support is disabled by #undefining CONFIG_WATCHDOG. It certainly seems that U-Boot is not responsible for the crash. Do you have any thoughts on this? I'd appreciate a bit of help. Rgds, -- Matt > Hi TsiChung, > > I can supply you my patch for a watchdog driver implementation for 5445x > to test with if you like? I've not fed it back to Freescale yet. Will do > though. It's based on 2.6.29. > > Is there a mechanism to allow U-Boot to indicate to Linux that it has > enabled the watchdog (eg as part of the bd_info struct maybe)? Just a > thought... It could then be kicked at kernel arch init and then repeatedly > by Linux user space via /dev/watchdog if required by the application. The > reason I suggested kicking the watchdog in arch init is to give Linux a > chance to boot (kernel and user) before the watchdog times out. Obviously > several things could prevent this (eg tasks that take time before user > space starts for example fsck etc). > > I'm sure other U-Boot developers/maintainers have thought about this..? > Thoughts? > > In any case, I need to enable the watchdog in U-Boot for a mcf54451 based > platform because need it in our system (we're using an mcf54455 evb as > reference hw). I'm happy to help in the development / testing etc. Please > just let me know. > > Best regards, > -- Matt > > >> Matt, >> >> Yes. I am planning to enable watchdog in mcf5445x in u-boot. Need to >> investigate more in booting linux and the transition to starting the >> linux kernel of watchdog behavior to make sure it is not causing problem >> to the linux kernel. >> >> Best Regards, >> TsiChung >> >> >> -----Original Message----- >> From: Matthew Lear [mailto:m...@bubblegen.co.uk] >> Sent: Monday, June 15, 2009 7:59 AM >> To: Liew Tsi Chung-R5AAHP; u-boot@lists.denx.de >> Subject: mcf5445x watchdog support in U-Boot >> >> Hi TsiChung et al, >> >> I was wondering if there are plans to support and utilise the watchdog >> in the mcf5445x devices within U-Boot? >> >> I've ported a kernel driver from the bitshrine gpp >> (http://www.bitshrine.org/gpp/linux-2.6.25-mcfv4e-watchdog.patch) so >> that it hooks into my 54455 hw (Freescale EVB), however I'd like to >> configure and enable the watchdog in U-Boot with the intention that once >> Linux starts, the responsibility of kicking the watchdog resides with a >> user space app -> driver. >> >> Thoughts? >> >> Much appreciated. >> -- Matt >> _______________________________________________ >> U-Boot mailing list >> U-Boot@lists.denx.de >> http://lists.denx.de/mailman/listinfo/u-boot >> >> > > > _______________________________________________ > U-Boot mailing list > U-Boot@lists.denx.de > http://lists.denx.de/mailman/listinfo/u-boot > > _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
