Root file system as CRAMFS on Flash

Purushothaman N purushn at
Mon Feb 24 05:24:26 EST 2003

Dear All,

Sorry for disturbing the list again. I was successfully able to mount a
image in flash with NFS as root file system. But i am facing problems with
mounting the cramfs image as root file system. I have given the correct root
to the kernel. Please find below the trace message printed during kernel

ttyS00 at iomem 0xb8000800 (irq = 0) is a 16550A
Attempt to register invalid minor number with devfs (0:0).
Attempt to register invalid minor number with devfs (0:0).
ttyS00 at iomem 0xb8000820 (irq = 0) is a 16550A
Attempt to register invalid minor number with devfs (0:0).
Attempt to register invalid minor number with devfs (0:0).
Loading RC323xx MMU routines.
CPU revision is: 00001800
Primary instruction cache 8kb, linesize 16 bytes (2 ways)
Primary data cache 2kb, linesize 16 bytes (2 ways)
Number of TLB entries 16.
Linux version 2.4.5-pre1 (root at (gcc version 2.95.3
Index:  0 pgmask=01ffe000 va=e0000000 asid=00000000  [pa=40000000 c=2 d=1
v=1 g]
memory: 801ffc00 @ 80000400 (usable)
 memory: 01c71c10 @ 0038e3f0 (usable)
 On node 0 totalpages: 8192
 zone(0): 4096 pages.
 zone(1): 4096 pages.
 zone(2): 0 pages.
 Kernel command line: root=/dev/mtdblock2
 calculating r4koff... 0007a120(500000)
 CPU frequency 100.00 MHz
Linux NET4.0 for Linux 2.4
Based upon Swansea University Computer Society NET3.039
Initializing RT netlink socket
Starting kswapd v1.8
block: queued sectors max/low 18880kB/6293kB, 64 slots per queue
devfs: v0.102 (20000622) Richard Gooch (rgooch at
devfs: devfs_debug: 0x0
devfs: boot_options: 0x0
loop: loaded (max 8 devices)
Serial driver version 5.05a (2001-03-20) with MANY_PORTS SHARE_IRQ
ttyS00 at 0x0000 (irq = 0) is a 16550A
ttyS01 at 0x0000 (irq = 0) is a 16550A
mtd: Giving out device 0 to M-Systems DiskOnChip 1000
M-Systems DiskOnChip driver. (C) 1999 Machine Vision Holdings, Inc.
Using configured probe address 0x4000000
After ioremap->docptr: 0xa4000000
Calling doccheck with docptr - 0xa4000000 and physadr - 0x4000000
 (docprobe.c:114)=> signature 0x55 0xAA not found!!!
 After iounmap->docptr: 0xa4000000
 mtd: Giving out device 1 to Raw memory
 Registered physmem device from 98304Kb to 131072Kb
 Mapped from 0x86000000 to 0x88000000
 Inter module registering - AMDEXT
 MIPS flash device: 800000 at 4000000
 Remapped address - 0xa4000000
 CFI probing with base = 0
 Value read at 0x2AA8 is - 0xffffffff
 MIPS Physically Mapped Flash: Found four side-by-side CFI devices at locae
 (cfi_probe.c:382)=> cfi.interleave: 4
 Primary Vendor Command Set: 0002 (AMD/Fujitsu Standard)
 Primary Algorithm Table at 0040
 Alternative Vendor Command Set: 0000 (None)
 No Alternate Algorithm Table
 Vcc Minimum: 2.7 V
 Vcc Maximum: 3.6 V
 No Vpp line
 Typical byte/word write timeout: 16 µs
 Maximum byte/word write timeout: 512 µs
 Full buffer write not supported
 Typical block erase timeout: 1024 µs
 Maximum block erase timeout: 16384 µs
 Chip erase not supported
 Device size: 0x200000 bytes (2 Mb)
 Flash Device Interface description: 0x0002
   - supports x8 and x16 via BYTE# with asynchronous interface
     Max. bytes in buffer write: 0x1
     Number of Erase Block Regions: 4
       Erase Region #0: BlockSize 0x4000 bytes, 1 blocks
         Erase Region #1: BlockSize 0x0100 bytes, 65 blocks
           Erase Region #2: BlockSize 0x2000 bytes, 2 blocks
             Erase Region #3: BlockSize 0x0000 bytes, 33 blocks

             Size of the map - 8192k
             Value read at 0x2AA8 is - 0xffffffff
             MIPS Physically Mapped Flash: Found four side-by-side CFI
devices at locae
             FIXME: Do alias check at line 289 of cfi_probe.c
             Request the Probe for :cfi_cmdset_0002
              Amd/Fujitsu Extended Query Table at 0x0040
              number of CFI chips: 1
              mtd: Giving out device 2 to MIPS root filesystem
              mtd: Giving out device 3 to MIPS boot firmware
              mtd: Giving out device 4 to MIPS kernel
              init_mtdblock called
              CONFIG_DEVFS_FS defined
              NET4: Linux TCP/IP 1.0 for NET4.0
              IP Protocols: ICMP, UDP, TCP
              IP: routing cache hash table of 512 buckets, 4Kbytes
              TCP: Hash tables configured (established 2048 bind 2048)
              IP-Config: Device `eth0' not found.
              ip_conntrack (256 buckets, 2048 max)
              ip_tables: (c)2000 Netfilter core team
              NET4: Unix domain sockets 1.0/SMP for Linux NET4.0.
              ROOT_DEVICE_NAME = mtdblock2
              handle = 0x0
              Kernel panic: I have no root and I want to scream

Also is it necessary to define device fs (CONFIG_DEVFS_FS) for using
Please help me to solve this issue.

Thanks and Regards,

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