(i posted on this on the ARM mailing list but i'm still waiting to
hear if my attempt at subscribing to that list was accepted. so i'll
reproduce the problem here and hope for the best.)
i have a technologic TS-7250 ARM-system with a homegrown in-flash
2.6.17 kernel and very old busybox-1.2.1 based root filesystem, but it
boots and runs just fine via the RedBoot bootloader.
the redboot-configured kernel command line is:
exec -c "console=ttyAM0,115200 root=/dev/mtdblock2"
so, obviously, /dev/ttyAM0 represents the console serial port and
/dev/mtdblock2 holds the rootfs. during the kernel boot process, you
can see, among other things:
...
Serial: AMBA driver $Revision: 1.41 $
apb:uart1: ttyAM0 at MMIO 0x808c0000 (irq = 52) is a AMBA
apb:uart2: ttyAM1 at MMIO 0x808d0000 (irq = 54) is a AMBA
apb:uart3: ttyAM2 at MMIO 0x808e0000 (irq = 55) is a AMBA
...
yaffs: dev is 32505858 name is "mtdblock2"
yaffs: Attempting MTD mount on 31.2, "mtdblock2"
Reading data from NAND FLASH without ECC is not recommended
Reading data from NAND FLASH without ECC is not recommended
VFS: Mounted root (yaffs filesystem).
Freeing init memory: 76K
Reading data from NAND FLASH without ECC is not recommended
Reading data from NAND FLASH without ECC is not recommended
mounting ramfs at /dev
mounting /proc
mounting /sys
starting udevd...
...
in other words, it all looks good.
now, what i'm trying to do is, using a custom 2.6.21 source tree
from technologic, build and boot a 2.6.21 kernel. i have access to
the 2.6.17 config file via /proc/config.gz so, reading through that,
i've tried to configure the 2.6.21 source tree as similarly as i can.
that doesn't quite do it as, once i build that new kernel and load it
into RAM via TFTP, i get:
...
Serial: AMBA driver $Revision: 1.1.1.1 $
apb:uart1: ttyAM0 at MMIO 0x808c0000 (irq = 52) is a AMBA
apb:uart2: ttyAM1 at MMIO 0x808d0000 (irq = 54) is a AMBA
apb:uart3: ttyAM2 at MMIO 0x808e0000 (irq = 55) is a AMBA
...
yaffs: dev is 32505858 name is "mtdblock2"
yaffs: passed flags ""
yaffs: Attempting MTD mount on 31.2, "mtdblock2"
VFS: Mounted root (yaffs filesystem).
Freeing init memory: 96K
Warning: unable to open an initial console.
Kernel panic - not syncing: No init found. Try passing init= option
to kernel.
from the above, it seems clear that the rootfs was mounted, but
that's as far as i get -- failure to open an initial console.
usually, i interpret that as that i'm missing, say, /dev/console or
something. but this is not as big a jump as going from a 2.4 to a 2.6
kernel. it's just 2.6.17.10 to 2.6.21, both kernels are trying to use
the same root filesystem, i've done everything i can to configure them
similarly, etc. so i'm kind of stumped. any thoughts as to what i
should be looking for?
i have access to the config files for both kernels, i can certainly
boot the 2.6.17 kernel and poke around, through things like lsmod and
/proc. i've tried everything i can think of to figure out why i can't
get an initial console. so i'm open to suggestions.
rday
--
========================================================================
Robert P. J. Day
Linux Consulting, Training and Annoying Kernel Pedantry:
Have classroom, will lecture.
http://crashcourse.ca Waterloo, Ontario, CANADA
========================================================================
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