[U-Boot-Users] RTC for MPC5200

Victor Wren vwren at timension.com
Fri Jan 9 01:23:14 CET 2004

On Thu, Jan 08, 2004 at 11:56:52PM +0100, Wolfgang Denk wrote:
> What exactly is the problem? The procedure is fairly well  documented
> in the DULG, and a ready-to-run image is supplied with the ELDK. Just
> boot it...

Oh, it boots, no problem.  What I'm having trouble with (inexperience) is
changing the root filesystem after and cutting all ties to busybox so that
I can unmount the ramdisk.  The closest I've gotten to booting is with

mount /dev/hda2 /mnt
cd /mnt
pivot_root . /mnt/initrd 
chroot . /etc/rc.sysinit <dev/console >dev/console 2>&1

But after that, I'm still running busybox, and when the "application" process
expires, it starts berating me.  Of course, I can't umount /initrd because
it's still occupied.   I've read up all I can find on the boot
process using initrd, and haven't found much specifics about handing over
control from one init process to another.

> A ramdisk image (loaded from flash) is one way to provide an embedded
> system  that  is  100%  bullet-proof  agains  unexpected  reboots  or
> power-cycling.

Well, this does have a hard drive attached, so there will still be some 
issues with filesystem recovery in case of accidents.  I'm using this 
more like a mini-server than an embedded system.

> Also, a more leaner setup like the busybox-based SELF  used  for  our
> defualt  ramdisk  images  boots much, much faster than the full-blown
> SysV init stuff.

It certainly does.  My cable box should start so fast.  

> You  will  not  be  judged  by  years  of  experience,  or   by   any
> certificates. It's just the quality of the code that matters :-)

That's what worries me. :-)  In my case, the years of experience were too
many years ago.  Last time I did much low-level code munching was on my Atari
ST.  MMUs were after my time.

Victor Wren

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