2.6.10 unable to mount a root fs on ramdisk

2.6.10 unable to mount a root fs on ramdisk

[Shawn Jin]

Hi,

Tried to mount a root fs on ramdisk on an ebony board but the
following error shows up.

Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(1=
,0)

There may be a simple answer for this common error. But I haven't
found out it after googling for a while. I remember I had a similar
problem when trying to mount a jffs2 as the root fs. The solution is
to add rootfstype=3Djffs2. I downloaded the ramdisk image from DENX's
ftp site. So I'm sure the image itself has no problem.

I already enabled RAMDISK and initrd support in kernel configuration.

=3D> run ramroot
## Booting image at 00400000 ...
   Image Name:   Linux-2.6.10
   Created:      2005-02-23  18:40:02 UTC
   Image Type:   PowerPC Linux Kernel Image (gzip compressed)
   Data Size:    887207 Bytes =3D 866.4 kB
   Load Address: 00000000
   Entry Point:  00000000
   Verifying Checksum ... OK
   Uncompressing Kernel Image ... OK
## Current stack ends at 0x07FA9CC0 =3D> set upper limit to 0x00800000
## cmdline at 0x007FFC00 ... 0x007FFC10
bd address  =3D 0x07FAAF90
memstart    =3D 0x00000000
memsize     =3D 0x08000000
flashstart  =3D 0xFF800000
flashsize   =3D 0x00480000
flashoffset =3D 0x00000000
sramstart   =3D 0x00000000
sramsize    =3D 0x00000000
bootflags   =3D 0x00000005
intfreq     =3D    400 MHz
busfreq     =3D 133.333 MHz
baudrate    =3D   9600 bps
## Loading RAMDisk Image at 00600000 ...
   Image Name:   Simple Embedded Linux Framework
   Created:      2002-10-24   9:30:38 UTC
   Image Type:   PowerPC Linux RAMDisk Image (gzip compressed)
   Data Size:    1476478 Bytes =3D  1.4 MB
   Load Address: 00000000
   Entry Point:  00000000
   Verifying Checksum ... OK
## initrd at 0x00600040 ... 0x007687BD (len=3D1476478=3D0x16877E)
   Loading Ramdisk to 07e41000, end 07fa977e ... OK
## Transferring control to Linux (at address 00000000) ...
Linux version 2.6.10  (gcc version 3.3.3 (DENX ELDK 3.1 3.3.3-8)) #1 We
d Feb 23 10:34:11 PST 2005
IBM Ebony port (MontaVista Software, Inc. (source@mvista.com))
<SNIPPED>
NET: Registered protocol family 1
NET: Registered protocol family 17
Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(1=
,0)

Thanks,
-Shawn.

Re: 2.6.10 unable to mount a root fs on ramdisk

[Shawn Jin]

Hi John,

Thanks for your answer.

I did add these lines to the code. Actually it turned out that I was
so stupid that I didn't enable EXT2 filesystem support in the kernel.
That's why the kernel always complained unknown block.

-Shawn.

On 5/23/05, John Otken <jotken@softadvances.com> wrote:
> I had this problem with MV code on a Bamboo board.  Look at
> platform_init() in ebony.c.  Before the call to ibm44x_platform_init() ad=
d:
>=20
>        /*
>         * If we were passed in a board information, copy it into the
>         * residual data area.
>         */
>        if (r3)
>                __res =3D *(bd_t *)(r3 + KERNELBASE);
>=20
>        /*
>         * If the init RAM disk has been configured in, and there's a vali=
d
>         * starting address for it, set it up.
>         */
>        if (r4) {
>            initrd_start =3D r4 + KERNELBASE;
>            initrd_end =3D r5 + KERNELBASE;
>        }
>=20
>        /* Copy the kernel command line arguments to a safe place. */
>=20
>        if (r6) {
>            *(char *) (r7 + KERNELBASE) =3D 0;
>            strcpy(cmd_line, (char *) (r6 + KERNELBASE));
>        }