VFS: Unable to mount root fs on unknown-block(220,0)

[pvinesh7]

Please see the log:
Can any one explain the reason for panic message and its solution:

<4>Linux version 2.6.10_mvl401 (root@mstclindt02 (gcc version 3.4.3 (MontaVista 3.4.3-25.0.104.0600975 2006-07-06)) #1 Tue Sep 9 21:23:02 IST 2008
<4>CPU: ARM926EJ-Sid(wb) [41069263] revision 3 (ARMv5TEJ)
<4>CPU0: D VIVT write-back cache
<4>CPU0: I cache: 16384 bytes, associativity 4, 32 byte lines, 128 sets
<4>CPU0: D cache: 8192 bytes, associativity 4, 32 byte lines, 64 sets
<4>Machine: DaVinci DM355 EVM
<4>Warning: bad configuration page, trying to continue
<4>Memory policy: ECC disabled, Data cache writeback
<4>DM0000
<4>DaVinci variant not supported
<3> : failed to get UART1 clock
<3> : failed to get UART2 clock
<7>On node 0 totalpages: 4096
<7> DMA zone: 4096 pages, LIFO batch:1
<7> Normal zone: 0 pages, LIFO batch:1
<7> HighMem zone: 0 pages, LIFO batch:1
<4>Built 1 zonelists
<4>Kernel command line: root=/dev//dev/root rootfs=ext2 ramdisk_size=32768 init=/bin/a.out initrd=0x83900000,4M console=ttyS0,115200n8
<4>PID hash table entries: 128 (order: 7, 2048 bytes)
<4>Console: colour dummy device 80x30
<4>Dentry cache hash table entries: 4096 (order: 2, 16384 bytes)
<4>Inode-cache hash table entries: 2048 (order: 1, 8192 bytes)
<6>Memory: 16MB = 16MB total
<5>Memory: 14912KB available (892K code, 234K data, 116K init)
<4>Mount-cache hash table entries: 512 (order: 0, 4096 bytes)
<6>CPU: Testing write buffer coherency: ok
<4>spawn_desched_task(00000000)
<4>desched cpu_callback 3/00000000
<4>ksoftirqd started up.
<4>desched cpu_callback 2/00000000
<4>desched thread 0 started up.
<6>Linux NoNET1.0 for Linux 2.6
<6>DaVinci: 104 gpio irqs
<6>Registering platform device 'serial8250.0'. Parent at platform
<6>Registering platform device 'musb_hdrc'. Parent at platform
<4>NetWinder Floating Point Emulator V0.97 (double precision)
<6>elevator: using anticipatory as default io scheduler
<6>io scheduler noop registered
<6>io scheduler anticipatory registered
<4>RAMDISK driver initialized: 1 RAM disks of 32768K size 1024 blocksize
<6>loop: loaded (max 8 devices)
<4>*******
<4>VFS: test name = </dev/root>
<4>VFS: fs_name = <ext2>
<4>VFS: tried fs_name = <ext2> err= -6
<4>VFS: No root yet, retrying to mount root on root (unknown-block(220,0))
<4>VFS: tried fs_name = <ext2> err= -6
<4>VFS: No root yet, retrying to mount root on root (unknown-block(220,0))
<4>VFS: tried fs_name = <ext2> err= -6
<4>VFS: No root yet, retrying to mount root on root (unknown-block(220,0))
<4>VFS: tried fs_name = <ext2> err= -6
<4>VFS: No root yet, retrying to mount root on root (unknown-block(220,0))
<4>VFS: tried fs_name = <ext2> err= -6
<4>VFS: No root yet, retrying to mount root on root (unknown-block(220,0))
<4>VFS: tried fs_name = <ext2> err= -6
<4>VFS: No root yet, retrying to mount root on root (unknown-block(220,0))
<4>VFS: Cannot open root device "root" or unknown-block(220,0)
<4>Please append a correct "root=" boot option
<0>Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(220,0)

[ndevel]

is that really a correct root path?

...
Kernel command line: root=/dev//dev/root rootfs=ext2 ramdisk_size=32768 init=/bin/a.out initrd=0x83900000,4M console=ttyS0,115200n8
...