software-triggered reset of MPC8541

Dan Wilson dwilson at
Thu Mar 23 01:28:10 EST 2006

My apologies for asking a question in this mailing list that is somewhat off-topic, but this is the best list I know of for such a question:

We are trying to implement a software function to reset an 8541.  The ELDK 4.0 kernel includes an abort() function that does this by setting the appropriate bits in DBCR0.  In our tests, this unfailingly reboots the unit.  A colleague has put an identical function into a non-linux-based application on which he is working, and finds that most of the time the unit reboots as expected, but sometimes it just hangs.

My question is: does the linux kernel do anything special to prepare the processor environment for this reboot prior to calling abort()?  The only thing I could find was a call to local_irq_disable(), which does:
static inline void local_irq_disable(void)
        __asm__ __volatile__("wrteei 0": : :"memory");
        unsigned long msr;
        __asm__ __volatile__("": : :"memory");
        msr = mfmsr();
        SET_MSR_EE(msr & ~MSR_EE);

As the 8541 is an E500 core, I believe it is the #ifdef CONFIG_BOOKE code that is being executed.  The wrteei 0 instruction is clear enough.  What does the rest of that line do (i.e., the repeated colons and the memory command)?  I haven't been able to find a memory command in the ppc instruction set documents that I have?

Thanks in advance for any help anyone can give to help us understand this code sequence better!

Best regards,


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