build kernel and rootfs , now what ?

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Hi

After building a first kernel image  and booting it :
apex> boot
ARCH_ID: 390 (0x186)
ATAG_HEADER
ATAG_MEM: start 0xc0000000  size 0x02000000
ATAG_MEM: start 0xc4000000  size 0x02000000
ATAG_CMDLINE: (74 bytes) 'console=ttyAM1 root=/dev/hda1
mtdparts=phys_mapped_fla
sh:2m(boot),-(root)'
ATAG_END
Booting kernel at 0xc0008000...
Uncompressing
Linux.............................................................
.......................... done, booting the kernel.
Linux version 2.6.16 (root@debian) (gcc version 3.4.4) #1 PREEMPT Sat
Feb 28 20:
42:00 CET 2009
CPU: ARM922Tid(wb) [41029220] revision 0 (ARMv4T)
..............
..............
Root-NFS: No NFS server available, giving up.
VFS: Unable to mount root fs via NFS, trying floppy.
VFS: Cannot open root device "hda1" or unknown-block(2,0)
Please append a correct "root=" boot option
Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-
block(2,0)

There was no rootfs at first, now i have build one, but what should i
do now with the resulting rootfs.image ?
My board has Flash, so i would like to put it there somewhere.

How do i tell the kernel how i should load the rootfs, and how do i
store the rootfs in flash ?
any hints ? (i am using a LH7a404 logicpd)

Johan








Re: build kernel and rootfs , now what ?
Please Goggle for "initramfs" and "u-boot"

-Michael

Re: build kernel and rootfs , now what ?
Quoted text here. Click to load it

do i need initramfs ?

ps  I made a brick from my SDK kit, i corrupted the bootloader....,
now i'm looking for a rope ...

Re: build kernel and rootfs , now what ?
Quoted text here. Click to load it

You seem to be able to hand control over to the Linux kernel, so I
dont think your bootloader is corrupt!!  What may be corrupt is how
you pass the arguments to the kernel.
1. What is the bootloader you are using ?
2. Have you read the manual for the bootloader and worked out what
arguments you are currently passing on to Linux ?
3. What are the arguments you pass on to linux ?
4. Your kernel is looking for a root file system on a NFS export.  Do
you have a NFS server setup to export a root filesystem ?
5. What are you intending to do with a brick and a rope ? :)

Re: build kernel and rootfs , now what ?
Quoted text here. Click to load it

The preinstalled bootloader is lolo (from logicpd)
then i loaded the APEX loader.
from that one i loaded my comiled kernel.
 i saw this line :
ATAG_CMDLINE: (74 bytes) 'console3D%ttyAM1 root3D%/dev/hda1
mtdparts3D%phys_mapped_flash:2m(boot),-(root)'
but there is no hda1 device, in an order to change this i did

then in the apex bootloader id did::
apex> erase $env
# erase nor:128k+64k
this seems to have overwritten part of the original bootloader, i get
no prompts anymore from the serial ports after reset,
and the leds on my baseboard no longer blinks....

so i ended up here with a useless system.

I think i will look for something with a AT91SAM926x device,  i think
its more recent than the lh7a404 and better supported, and i have
complete schematics of a module build with that cpu  ( no hidden stuff
in cpld's like in the logicpd lh7a404 module )


Johan


Re: build kernel and rootfs , now what ?
Quoted text here. Click to load it

Its hard to say without knowing your system.  But as I can see it, you
have two options.
a) Use a JTAG device to program the original bootloader (assuming you
have a JTAG pod and the old bootloader bin file handy)
b) Manually program the flash/Eeprom (lot of work required)
Good luck
 Janaka

Re: build kernel and rootfs , now what ?
gates killer wrote:>
Quoted text here. Click to load it
Not necessarily, but IMHO initramfs is the easiest way to boot most
embedded devices, when, unlike with PCs, you just stay in the state with
initramfs as the root file system:

The boot loader only needs to move a single file into RAM: the self
extracting Kernel. Same includes the initramfs, which is automatically
extracted and mounted by the Kernel after same extracted itself. Now
initramfs is readable and writable.

If you need additional File systems you can create them in additional
Flash partitions using MTD and jffs2.

-Michael

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