set root variable for uImage?

Sascha Hauer s.hauer at pengutronix.de
Wed Jul 3 16:26:35 EDT 2013


On Wed, Jul 03, 2013 at 08:30:10PM +0200, Adam Furmanczuk wrote:
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> On 03.07.2013 18:58, Sascha Hauer wrote:
> > Hi Adam,
> > 
> > On Wed, Jul 03, 2013 at 05:21:37PM +0200, Adam Furmanczuk wrote:
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> >> Hi,
> >> 
> >> I restate this question from my previous thread "how to flash and
> >> set root variable". Thanks very much to Sascha and Alexander for
> >> introducing into barebox building and flashing.
> >> 
> >> I have a basic scenario. Want to boot uImage and then hand over 
> >> to the root partition. With u-Boot this was very easy:
> >> 
> >> setenv bootargs "console=tty0 console=ttymxc0,115200n8 
> >> root=/dev/mmcblk0p3 rootfstype=ext4 rootwait ro"
> >> 
> >> With barebox however, when I boot the uImage, it complains about
> >>  not setting correct "root=".:
> >> 
> >> [ 1.718527] VFS: Cannot open root device "(null)" or 
> >> unknown-block(0,0): error -6 [ 1.726226] Please append a correct
> >>  "root=" boot option; here are the available partitions:
> >> 
> >> Now what i do in Barbox is the following;
> >> 
> >> (hint enter to go into console) barebox at myhost:/ mkdir /media2 
> >> barebox at myhost:/ mount /dev/disk0.1 fat /media2 barebox at myhost:/
> >>  bootm /media2/uImage root=/dev/mmcblk0p3 rootfstype=ext4
> > 
> > the bootm command evaluates the 'bootargs' environment variable,
> > so before executing bootm do a:
> > 
> > export bootargs="root=/dev/mmcblk0p3 rootfstype=ext4"
> > 
> > (sidenote: This is not documented with 'help bootm', shame on us. 
> > Try the 'magicvar' command instead which lists all variables with 
> > special meanings)
> > 
> > Sascha
> > 
> 
> Hi Sascha,
> 
> it does not seem to work for me, I typed:
> 
> mkdir /mnt/disk1
> bootargs="root=/dev/mmcblk0p3 rootfstype=ext4"
> mount /dev/disk0.1 fat /mnt/disk1
> bootm /mnt/disk1/uImage
> 
> 
> I choose different values for root, like "mmcblk0p3","/dev/mmcblk0p1",
> "b303" ...
> 
> I am running MX53QSB with barebox 2013.05 build get this output:

The kernel normally prints the commandline during startup. Could you
post it?

Then, are you using some defconfig or do you you have out of tree
patches?

Also, could you post the output of 'devinfo global'?

Sascha

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