[U-Boot-Users] Linux kernel ignoring bootargs

[U-Boot-Users] Linux kernel ignoring bootargs

[Timur Tabi]

I'm trying to boot a Linux 2.6.17 kernel from U-Boot, and it appears that it's ignoring the bootargs variable in U-Boot.

Here is my U-Boot environment:

baudrate=115200
loads_echo=1
ethaddr=00:E0:0C:00:8C:01
eth1addr=00:E0:0C:00:8C:02
ipaddr=10.82.19.159
serverip=10.82.48.106
rootpath=/nfsroot0/u/timur/itx-ltib/rootfs
gatewayip=10.82.19.254
netmask=255.255.252.0
hostname=timur-dev
bootfile=/timur/uImage
loadaddr=200000
netdev=eth0
tftpuboot=tftpboot $loadaddr timur/u-boot.bin; erase fe700000 fe77ffff; cp.b $loadaddr fe700000 $filesize; cmp.b $loadaddr fe700000 $filesize
tftplinux=tftpboot $loadaddr /timur/uImage
ethact=TSEC0
bootargs=root=/dev/nfs rw nfsroot=10.82.48.106:/nfsroot0/u/timur/itx-ltib/rootfs ip=10.82.19.159:10.82.48.106:10.82.19.254:255.255.252.0:timur-dev:eth0:off console=ttyS0,115200
stdin=serial
stdout=serial
stderr=serial

And here's what Linux says when it boots:

## Booting image at 00200000 ...
    Image Name:   Linux-2.6.17-g339d76c5-dirty
    Image Type:   PowerPC Linux Kernel Image (gzip compressed)
    Data Size:    1401739 Bytes =  1.3 MB
    Load Address: 00000000
    Entry Point:  00000000
    Verifying Checksum ... OK
    Uncompressing Kernel Image ... OK
## Current stack ends at 0x0FF71D18 => set upper limit to 0x00800000
## cmdline at 0x007FFF00 ... 0x007FFFA7
bd address  = 0x0FF71FBC
memstart    = 0x00000000
memsize     = 0x10000000
flashstart  = 0xFE000000
flashsize   = 0x01000000
flashoffset = 0x00000000
sramstart   = 0x00000000
sramsize    = 0x00000000
bootflags   = 0x00000001
intfreq     = 533.333 MHz
busfreq     = 266.666 MHz
ethaddr     = 00:E0:0C:00:8C:01
eth1addr    = 00:E0:0C:00:8C:02
IP addr     = 10.82.19.159
baudrate    = 115200 bps
No initrd
## Transferring control to Linux (at address 00000000) ...
[    0.000000] Using MPC834x ITX machine description
....
[   41.727079] IP-Config: Complete:
[   41.730136]       device=eth0, addr=192.168.1.141, mask=255.255.255.0, gw=192.168.1.1,
[   41.737995]      host=unknown, domain=, nis-domain=(none),
[   41.743479]      bootserver=192.168.1.1, rootserver=192.168.1.1, rootpath=

As you can see, it's using the wrong IP address.  It's using the one hard-coded into the kernel's configuration.  I thought 'bootargs' was supposed to override that?

-- 
Timur Tabi
Linux Kernel Developer @ Freescale

[U-Boot-Users] Linux kernel ignoring bootargs

[David Hawkins]

Timur Tabi wrote:
> I'm trying to boot a Linux 2.6.17 kernel from U-Boot, and 
> it appears that it's ignoring the bootargs variable in U-Boot.

Try clearing bootargs, and then setting it again.

I had a similar issue, and this fixed it. My assumption
was that I'd got a control character in there that made it
appear sane, when in fact it was not. A binary dump of
the arguments area would probably confirm it.

Also you need to watch out for repeated environment
variables, if something is defined twice, it'll pickup
the first, but redefinition will affect the second.
I saw this when updating U-Boot and picking up the
default environment, i.e., a couple of things appeared
to be defined twice ... I figured it was user-error :)

Cheers
Dave

[U-Boot-Users] Linux kernel ignoring bootargs

[Timur Tabi]

David Hawkins wrote:
> Timur Tabi wrote:
>> I'm trying to boot a Linux 2.6.17 kernel from U-Boot, and it appears 
>> that it's ignoring the bootargs variable in U-Boot.
> 
> Try clearing bootargs, and then setting it again.

Doesn't help.

It looks like there's a command line hard-coded into the kernel:

[    0.000000] Kernel command line: root=/dev/nfs rw nfsroot=192.168.1.1:/nfsroot0/u/timur/itx-ltib/rootfs ip=192.168.1.141:192.168.1.1:192.168.1.1:255.255.255.0:unknown:eth0:off console=ttyS0,115200

I can't figure out how it got there.  I know I put it there, because the IP addresses are correct for the test board that's in the lab.  It's not correct, however, for the board in my office.

ACK!  I just remembered - the command line is hard-coded in the device tree, which is hard-coded in the kernel image.  Crap.  Oh well, thanks for helping me remember!

-- 
Timur Tabi
Linux Kernel Developer @ Freescale