Booting from RAM Disk

Booting from RAM Disk

[Matt Jerdonek]

I've got a custom 852T board, similar to an AdderII. 
I've got the board booting linux fine using NFS.  Now
I'm trying to get it to work stand-alone, and I can't
get it to boot from a RAM disk.  I'm using the 2.4.25
kernel from Denx, and the Ramdisk image from the ELDK
(ppc_8xx/images/ramdisk.image.gz).

Below is the output I'm getting.  The "MAJ" tags
indicate printk's that were inserted by me.  If anyone
has a clue to what I'm doing wrong, I'd appreciate it.

Thanks,
-- Matt

loaded at:     00380000 005C1218
board data at: 01FFFEF8 01FFFF48
relocated to:  003852FC 0038534C
zimage at:     00385848 00431C28
initrd at:     00432000 005BD040
avail ram:     005C2000 02000000

Linux/PPC load: root=/dev/ram rw ip=192.168.0.6
console=ttyS0,115200
Uncompressing Linux...done.
Now booting the kernel
Linux version 2.4.25 (matt@debian) (gcc version 3.3.3
(DENX ELDK 3.1.1 3.3.3-9)) #5 Fri Jan 6 13:58:44 MST
2006
On node 0 totalpages: 8192
zone(0): 8192 pages.
zone(1): 0 pages.
zone(2): 0 pages.
Kernel command line: root=/dev/ram rw ip=192.168.0.6
console=ttyS0,115200
Decrementer Frequency = 186624000/60
Calibrating delay loop... 49.56 BogoMIPS
Memory: 29164k available (1204k kernel code, 364k
data, 56k init, 0k highmem)
Dentry cache hash table entries: 4096 (order: 3, 32768
bytes)
Inode cache hash table entries: 2048 (order: 2, 16384
bytes)
Mount cache hash table entries: 512 (order: 0, 4096
bytes)
Buffer cache hash table entries: 1024 (order: 0, 4096
bytes)
Page-cache hash table entries: 8192 (order: 3, 32768
bytes)
POSIX conformance testing by UNIFIX
Linux NET4.0 for Linux 2.4
Based upon Swansea University Computer Society
NET3.039
Initializing RT netlink socket
Starting kswapd
devfs: v1.12c (20020818) Richard Gooch
(rgooch@atnf.csiro.au)
devfs: boot_options: 0x1
Installing knfsd (copyright (C) 1996
okir@monad.swb.de).
JFFS2 version 2.2. (C) 2001-2003 Red Hat, Inc.
CPM UART driver version 0.04
ttyS0 at 0x0280 is on SMC1 using BRG1
ttyS1 at 0x0200 is on SCC3 using BRG2
pty: 256 Unix98 ptys configured
eth0: FEC ENET Version 0.3, FEC irq 3, addr
08:00:3e:28:7a:ba
RAMDISK driver initialized: 16 RAM disks of 4096K size
1024 blocksize
loop: loaded (max 8 devices)
PPP generic driver version 2.4.2
PPP Deflate Compression module registered
NET4: Linux TCP/IP 1.0 for NET4.0
IP Protocols: ICMP, UDP, TCP, IGMP
IP: routing cache hash table of 512 buckets, 4Kbytes
TCP: Hash tables configured (established 2048 bind
4096)
IP-Config: Guessing netmask 255.255.255.0
IP-Config: Complete:
      device=eth0, addr=192.168.0.6,
mask=255.255.255.0, gw=255.255.255.255,
     host=192.168.0.6, domain=, nis-domain=(none),
     bootserver=255.255.255.255,
rootserver=255.255.255.255, rootpath=
NET4: Unix domain sockets 1.0/SMP for Linux NET4.0.
RAMDISK: Compressed image found at block 0
Freeing initrd memory: 1580k freed
MAJ: initrd_load returns 1
MAJ: In mount_root
MAJ: devfs_make_root name = ram
MAJ: create_dev returns 0
MAJ: mount_block_root fs_name = jffs2
Kernel panic: VFS: Unable to mount root fs on 01:00
 <0>Rebooting in 180 seconds..                        
     


		
__________________________________________ 
Yahoo! DSL – Something to write home about. 
Just $16.99/mo. or less. 
dsl.yahoo.com 

Re: Booting from RAM Disk

[Matt Jerdonek]

I didn't have the EXT2 file system enabled in the
kernel.  Thanks to Mark Chambers for pointing that
out.

-- Matt






		
__________________________________________ 
Yahoo! DSL – Something to write home about. 
Just $16.99/mo. or less. 
dsl.yahoo.com 

Re: Booting from RAM Disk

[David H. Lynch Jr.]

	initramfs does nto exist in 2.4, but despite a dearth of information it
works extremely well in 2.6.

	Set CONFIG_INITRAMFS=path to directory tree to build into ramdisk, and
the kernel building process will take care of most evrything else.
Unlike initrd, there are not two separate files, that each have to be
loaded. The initial ramdisk is part of the kernel image, gets
uncompressed by the kernel, and is just generally painless - except for
the scarcity of documentation.

Re: Booting from RAM Disk

[Grant Likely]

David H. Lynch Jr. wrote:
> 	initramfs does nto exist in 2.4, but despite a dearth of information it
> works extremely well in 2.6.
> 
> 	Set CONFIG_INITRAMFS=path to directory tree to build into ramdisk, and
> the kernel building process will take care of most evrything else.
> Unlike initrd, there are not two separate files, that each have to be
> loaded. The initial ramdisk is part of the kernel image, gets
> uncompressed by the kernel, and is just generally painless - except for
> the scarcity of documentation.
So... have are been able to use initramfs as a drop in replacement for
initrd, or did you have to jump through extra hoops?  I attempted to use
initramfs a few months ago, but wasn't ever able to get it to run init.

g.

-- 
Grant Likely, B.Sc. P.Eng.
Secret Lab Technologies Ltd.
(403) 663-0761

Re: Booting from RAM Disk

[David H. Lynch Jr.]

Grant Likely wrote:
> David H. Lynch Jr. wrote:
> 
>>	initramfs does nto exist in 2.4, but despite a dearth of information it
>>works extremely well in 2.6.
>>
>>	Set CONFIG_INITRAMFS=path to directory tree to build into ramdisk, and
>>the kernel building process will take care of most evrything else.
>>Unlike initrd, there are not two separate files, that each have to be
>>loaded. The initial ramdisk is part of the kernel image, gets
>>uncompressed by the kernel, and is just generally painless - except for
>>the scarcity of documentation.
> 
> So... have are been able to use initramfs as a drop in replacement for
> initrd, or did you have to jump through extra hoops?  I attempted to use
> initramfs a few months ago, but wasn't ever able to get it to run init.
> 
> g.
> 

	I can't exactly answer that - While I have used both, The only one I
have actually tried to put onto an embedded system is initramfs.

	I normallly use Debian which puts together an initrd for you fairly easily.
	I used Gentoo on a few systems and it uses initramfs - but it seems to
use it in an odd configuration similair to initrd, where the Ramdisk
image is a separate file.

	I have never tried to build an initrd system.

	I like initramfs - the only problem I had putting it together was
finding the information to do it.

	In the instance of the E12 I needed something that was wrapped into a
single file with the kernl. The E12 already had an elf loader, but all
it did was load elf files. It did not handle ramdisk other images etc.
INITRAMFS provided a means to start on the E12 without having to write
another loader.

Re: Booting from RAM Disk

[Grant Likely]

David H. Lynch Jr. wrote:
> Grant Likely wrote:
> 
> 	I have never tried to build an initrd system.

rolling up an initrd & kernel is actually very simple; but I had to read
the Makefile to figure out how to do it!  I do it by copying
ramdisk.image.gz into arch/ppc/boot/images and building 'make
zImage.initrd'.

> 
> 	I like initramfs - the only problem I had putting it together was
> finding the information to do it.
> 
> 	In the instance of the E12 I needed something that was wrapped into a
> single file with the kernl. The E12 already had an elf loader, but all
> it did was load elf files. It did not handle ramdisk other images etc.
> INITRAMFS provided a means to start on the E12 without having to write
> another loader.

So... how do you build the initramfs?

I'd prefer to use initramfs; I just haven't had a whole lot of luck with
it and other concerns took my focus.  :/

Thanks,
g.

-- 
Grant Likely, B.Sc. P.Eng.
Secret Lab Technologies Ltd.
(403) 663-0761