Rebooting the mpc8544

Sebastian Andrzej Siewior linuxppc-dev at ml.breakpoint.cc
Wed Nov 5 23:37:15 EST 2008


I'm trying to reboot the mpc8544 and pass the reason of the reboot (two
bits would be enough). I've been told the a PowerPC cpu has usually a
few registers which will survive a soft reset.
The "normal" reboot is done via the HRESET_REQ line which is handeled
by externel HW and does a power cycle.
The e500 watchdog also uses the HRESET_REQ line.
Other way would be use the Debug Control Register 0 (DBCR0) and set the
reset bit. The manual says here that it does a hard reset so none of
my registers will survive, right? There is a Most recent reset (MRR) bit
in the Debug Status Register (DBSR) but that one should be always set
since the last reset was a hard reset.
Right now I'm thinking about stealing a page and put the information
there since the memory controller isn't re-initialized.
Does someone have a better idea?

Sebastian



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