mpc8xx-2.2.13 kernel hangs during boot.

Brendan John Simon Brendan.Simon at
Tue Feb 1 21:00:14 EST 2000

I am trying to get mpc8xx-2.2.13 booting.  As far as I can tell, it is
hanging just after the kernel is decompressed into RAM and tries to
execute.  I get the following console output

    loaded at:     FF801000 FF80C1F0
    Relocate to:   00100000 0010B1F0
    Board Data at: 001001C4 001001E0
    relocated to:  00200100 0020011C
    Boot args at:  00200000 00200200
    zimage at:     FF807000 FF8676C8
    avail ram:     00201000 01000000

    Linux/PPC load:
    Uncompressing Linux... done.
    Now booting the kernel

I'm a little concerned about the overlap of BootArgs and the relocated
BoardData.  Does this seem right or wrong to anyone ?

I had previously had similar problem when using embedded-2.2.5.  It was
hanging during the boot.  It was suggested to me that I disable the
caches.  I did that in arch/ppc/mbxboot/head.S and
arch/ppc/kernel/head.S and I never had a problem booting embedded-2.2.5
since.  It was suggested to me that the UPM was probably incorrect and
that's why it fails with the caches enabled.
I have disabled the caches in mpc8xx-2.2.13 but I still get the same
results.  I have tried with 4 different UPM settings for a 25MHz bus
with 60ns EDO DRAM.  I got the values from the ADS manual, SDS Single
Step debugger and a commercial operating system.  I even tried with the
burst inhibit flag set/cleared in the chip select option registers.

I'm not sure if it is my bootloader or kernel.  In the bootloader I
basically setup the clocks, ports, chip selects for flash and dram and
that's about it.  Is there anything else the kernel expects to be setup

I've run out of ideas now and need some advice.
What could be causing the kernel not to boot ?
How can I tell where it is failing ?  I don't think I can use printk as
the console is not setup yet.  Is this correct ?

Getting a little desperate now.
Brendan Simon.

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