I am new to DM355 based product development. My current requirements is: It should be possible to change both kernel and application in the field by customer(user). I learnt from Phil/Jon that U-Boot does not need to change for this. Phil says that a startup updater service can be created to do this job. A PC connected to the DM355 on ethernet will send send a command to DM355 from a GUI based application and the DM355 will reboot on getting this command so that the updater service (as suggested by Phil) will get a chance to run at startup and will update the kernel and/or application. Something like this or may be different is needed to meet the goal.
Also in event that kernel does not come up because of any curruption, I should be able to reprogram it and application to recover from this state. Can someone kindly suggest me where I can learn how to do this. I am new to DM355 and linux. My past experience has been on Atmel microcontroller based app development using C but without using any standard real time OS. --- On Tue, 10/14/08, Phil Quiney <[EMAIL PROTECTED]> wrote: > From: Phil Quiney <[EMAIL PROTECTED]> > Subject: RE: DM355 bootloader > To: "Jon Povey" <[EMAIL PROTECTED]>, [EMAIL PROTECTED], > [email protected] > Date: Tuesday, October 14, 2008, 7:00 PM > Hi Jon, > > Looks like we are treading similar ground ;-) > > I have been considering a 'restore to factory > default' feature (post upgrade catastrophy fix). > > I have been looking at using 'unionfs' to provide a > single filesystem that is actually comprised of 2 > partitions, one writeable and one read only. All writes to > the file system pysically get written to the writable > partition and attempts to delete files in the read only > partition cause 'mask files' to appear in the > writable partition that make the file disappear when viewed > from the union. > > We can at any time go back to 'factory' conditions > by simply erasing the writeable partition. This is the > technique the Asus EeePC uses. > > Unfortunately on the 2.6.10 kernel, unionfs ran fine for a > day or so but then silently locked up the board. I was going > to try 'aufs' (as used by Slax) but have not had the > time to progress it. Also my first effort 'unioned' > the whole filesytem - it might be better to only do part of > the filesytem. > > Regards > > Phil Q > > > Phil Quiney, Principal Software Engineer > Trinity Convergence > Cambridge Business Park > Cowley Road > Cambridge CB4 0WZ, UK > T: +44(0)1223-435536 > F: +44(0)1223-435560 > www.trinityconvergence.com > > > -----Original Message----- > From: > [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] > On Behalf Of Jon Povey > Sent: 14 October 2008 14:15 > To: [EMAIL PROTECTED]; > [email protected] > Subject: RE: DM355 bootloader > > Phil wrote: > > > AFAIK 'UBL' is the U-Boot Loader - that is a > very small program that > > copies the U-Boot image from NAND into RAM and runs > it. This may well > > be an assembly language program (I have never had any > reason to study > > it) so good luck if you want to change it. > > The UBL is a TI app, I think it stands for "User Boot > Loader" (At least on DM355). > I have seen source for it, somewhere.. > UBL is needed because u-boot can't load itself from > NAND flash, and you can't do XIP. > > Confusing side-note: > > I'm a bit less sure why the RBL can't load u-boot > directly.. I think I worked it out at some point, it's > because the RBL can only load something that fits into one > block, or something like that. The TI UBL is just a little > bit of glue between RBL and u-boot, as I understand it. > > > U-Boot is the boot loader. It allows rudimentary > access to the FLASH > > and RAM on the board and typically a way of loading an > operating > > system kernel. Integrating an app updater into this > may be a challenge > > especially as it knows nothing about JFFS/YAFFS > filesystems. You may > > be able to FLASH the entire filesystem but that gets > interesting if > > the filesystem image won't fit in RAM and you have > to know about any > > bad blocks in the NAND as well. > > I am looking into how to do all this stuff on DM355 at the > moment. My current plan is to have two copies of the kernel, > two entirely separate filesystem partitions, and update one > while the other is running, then switch (probably by > changing u-boot environment variables). > > -- > Jon Povey, Design Engineer > [EMAIL PROTECTED] | +44(0)1280 825983 > > > Racelogic is a limited company registered in England. > Registered number 2743719 . > Registered Office Unit 10, Swan Business Centre, Osier Way, > Buckingham, Bucks, MK18 1TB . > The information contained in this electronic mail > transmission is intended by Racelogic Ltd for the use of the > named individual or entity to which it is directed and may > contain information that is confidential or privileged. If > you have received this electronic mail transmission in > error, please delete it from your system without copying or > forwarding it, and notify the sender of the error by reply > email so that the sender's address records can be > corrected. The views expressed by the sender of this > communication do not necessarily represent those of > Racelogic Ltd. Please note that Racelogic reserves the right > to monitor e-mail communications passing through its > network > > _______________________________________________ > Davinci-linux-open-source mailing list > [email protected] > http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source _______________________________________________ Davinci-linux-open-source mailing list [email protected] http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
