Problem when loading initrd

[wilbur.chan]

I got some problems when starting a kernel withCONFIG_BLK_DEV_RAM  and
using initrd-image (not cpio)    (mpc85xx)

RAMDISK: ext2 filesystem found at block 0
RAMDISK: Loading 4096KiB [1 disk] into ram disk... RAMDISK: Loading
4096KiB [1 d
isk] into ram disk... done.

No filesystem could mount root, tried: No filesystem could mount root, tried:

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




kernel boot param:  bootargs root=/dev/ram console=ttyS0,115200

I guess the problem lie in :

mount_root-->mount_block_root--->do_mount_root--->
sys_mount(name, "/root")

but I don't know  where the problem is . Any suggestions?  Thank you very much.