Reboot Command Makes kernel to hang (MPC8560)

Clemens Koller clemens.koller at
Tue Jul 31 21:44:05 EST 2007

Hi, Ansari!

Ansari schrieb:
> Hi Kumar,
> First of all thanks for ur reply .
> Even i went through the linux source . And i have observe that the reboot 
> command used to hard reset the core . I have few doubts can u please clarify 
> me.
> 1. Is there any way to reset the full chip with out using any external 
> signal (MPC8560) ? (like any register that can be used for reseting the 
> processor)

It should be the bits RST[1:0] in the Debug Control Register 0 (DBCR0).

I didn't find details how the external signals are affected: HRESET_REQ# and friends.
The HRESET_REQ# is usually fed back to the CPU's HRESET#.
So if the HRESET_REQ# gets asserted by writing to above registers it should really bring
down the CPU, it's internal as well as it's external components, which are usually
connected to a replication of that signal.

However the existence of cpm2_reset() and a qe_reset() (QuiccEngine?)
in the code tells me that the above expectations could be wrong.

Would be nice to have that verified by some hardware guys from freescale...

> 2. Even same reboot command works fine for MPC8540 Processor ?.

...because it doesn't have a cpm ?

> 3. what are the factors that makes ramdisk hangs . When its uncompressing ?

Well, side effects ?

Clemens Koller
R&D Imaging Devices
Anagramm GmbH
Rupert-Mayer-Straße 45/1
Linhof Werksgelände
D-81379 München
Fax 089-741518-19

More information about the Linuxppc-embedded mailing list