[U-Boot-Users] u-boot kernel parameters

[S. Egbert <s.egbert@sbcglobal.net>]

You've entered the dark nether region of console-less portion of the
bootup code WAY before the Linux console driver is installed... and it
stop somewhere OR merrily went on its way to Linux bootup WITHOUT a console.

Once it switched from old (usually flat) memory model to virtual memory
(MMU), all bets are off.  Couple of ways to shine a light where the
cockroaches are, are to try the following:

1.  Pass a boot command line 'console=/dev/ttyS0' from your bootloader
or have it compiled in via 'make menuconfig'  Check your custom serial
driver for the exact TTY device template name (i.e., /dev/ttl0,
/dev/ttyAS0).

2. Another way to see what is going on is to flip on the
CONFIG_TEXT_CONSOLE_DEBUG and insert MANY ppc_md.progress() calls AFTER
the debug console is initialized in arch/ppc/kernel/ppc4xx_setup.c

3. Put a Linux boot command line of 'kgdb' with CONFIG_KGDB to evoke a
hardware break and then use hardware debuggerto step through the Linux
bootup sequence.

4.  Make heavy use of on-board LED indicators by calling ioremap() and
poking your virtualized hardware register location to flip on the LED
indicators.


Anyway you cut, slice or dice it, this effort will require LOTS of
recompile, relink, reload and re-run will be required to 'normalize' a
new board bring-up.

Good Luck

S. Egbert


Bizzu (sent by Nabble.com) wrote:
> Hi all,
> I have an ocotea board, the denx latest 2.6 and 2.4 kernel and u-boot 1.1.4.
> I downloaded everything from Wolfgang's ftp site and followed the instructions by the letter. I tftp into memory (at 100000) and bootm my kernels.
> I successfully boot linux 2.6 (2.6.14-rc3) on this board but kernel 2.4 (2.4.25) wont take off.
> This is what 2.4 gives me: 
> (I added early serial messages for clarity)
> 
> ## Booting image at 00100000 ...
>    Image Name:   Linux-2.4.25
>    Created:      2006-02-07   2:25:05 UTC
>    Image Type:   PowerPC Linux Kernel Image (gzip compressed)
>    Data Size:    628718 Bytes = 614 kB
>    Load Address: 00000000
>    Entry Point:  00000000
>    Verifying Checksum ... OK
>    Uncompressing Kernel Image ... OK
> id mach(): done
> MMU:enter
> MMU:hw init
> MMU:mapin
> MMU:mapin_ram done
> MMU:setio
> MMU:exit
> setup_arch: enter
> setup_arch: bootmem
> arch: exit
> arch: exit 2
> 
> Anyone has an idea what could be wrong?
>