405GP interrupts tip and looking for a little console help

Mark Pilon mpilon at midrivers.com
Thu Nov 8 10:00:36 EST 2001


I'm bringing up the _devel kernel on a custom ppc405 board and
wanted to offer a little tip which might save some of you some

if your boot rom doesn't have much to do w/ interrupts (and mine
doesn't) nothing will set the UIC polarity register so that the
UIC responds correctly to on-chip interrupts.  I mention the boot
rom as it seems linux depends upon this setup happening upstream
of it.

In my case, failing to set all the UIC_PR bits for on-chip peripherals
to 1 meant I kept getting unexpected interrupts.  the first
occasion of this was initing the ethernet controller ...

in any case, write the correct value for your processor to
DCRN_UICPR -- w/ a mask of 1s for each on-chip peripheral.

AND I'd appreciate a little help on getting my console to
talk w/ me -- I boot, mount a remote target filesystem w/ nfs,
and get console messages right up to:

NET4: Unix domain sockets 1.0/SMP for Linux
Looking up port of RPC 100003/2 on
Looking up port of RPC 100005/1 on
VFS: Mounted root (nfs
Freeing unused kernel memory: 56k
^^^^^^----- I typed this last line and it echo'd,
I passed in a command init=/sbin/sash, but don't get its prompt,

I debugged it to the point of seeing the exec of /bin/sash,
and would appreciate any views as to what I've forgotten here.



Mark Pilon

P.O. Box 37
Fallon, MT.  59326-0037


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