[Buildroot] booting JFFS2 or UBIFS created with buildroot

[ANDY KENNEDY]

> From: Charles Krinke [mailto:charles.krinke at gmail.com] 
> Sent: Monday, February 21, 2011 3:30 PM
> To: ANDY KENNEDY
> Cc: buildroot at busybox.net
> Subject: Re: [Buildroot] booting JFFS2 or UBIFS created with buildroot
>
> Dear Andy et.al.:
>
> When I boot a jffs2 image created with buildroot with its associated
> kernel, I get a kernel panic when trying to mount the jffs2 image that
> looks like this:
>
> VFS: Cannot open root device "mtdblock2" or unknown-block(2,0)
> Please append a correct "root=" boot option; here are the available partitions:
> Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(2,0)
> Call Trace:
> [c3823ed0] [c0008270] show_stack+0x48/0x168 (unreliable)
> [c3823f10] [c03049c0] panic+0xa4/0x1e4
> [c3823f60] [c03b6de4] mount_block_root+0x198/0x240
> [c3823fb0] [c03b70e0] prepare_namespace+0x13c/0x1d0
> [c3823fd0] [c03b6258] kernel_init+0x138/0x174
> [c3823ff0] [c000f21c] kernel_thread+0x4c/0x68
> Rebooting in 180 seconds..
>
> My bootcmd and bootargs in u-boot looks like this:
>
> bootcmd=bootm 0xfe120000 - 0xfe080000
> bootargs=root=/dev/mtdblock2 rootfstype=jffs2
> mtdparts=nor:1152k(U-Boot),2176k(kernel),-(JFFS2) rw console=ttyS0,115200
>
> As I recall, this was working the last time I did it 5 years ago, but
> again, I probably have forgotten a few details or there are some
> config options not yet turned on. I am working with buildroot defaults
> so far.
>
> Charles

This looks like you don't have your NAND/NOR flash configured in the kernel.