Clock not running (was Re: RTEMS4.7 and its tool chain (Re: powerpc mvme5500 clock off by factor of 150))
strauman at slac.stanford.edu
Tue Mar 8 21:35:48 UTC 2005
Peter Dufault wrote:
> On Mar 8, 2005, at 3:39 PM, Till Straumann wrote:
>> Hence, you'd have to print the GPP_Interrupt_Cause register contents
>> to find the culprit [why the code in irq.c is so complicated is a
>> mystery to me].
> The higher level code had derived register "56" as I'd mentioned,
> which traced back to the serial port interrupt. Printing out the
> ever-pending GPP_Interrupt_Cause is "0x01", which also points to the
> serial port.
> I wish there was a way to see that a PPC decrementer interrupt was
> pending, because then I'd just call the decrementer ISR when interrupt
> "56" was called and an interrupt was pending as a proof that this is
> the problem, but I don't see that that is visible in any register.
> On the web I see references to errata on the serial port on the
> undocumented interface chip.
Not necessarily a HW bug. Could be that MotLoad uses the serial
interface in interrupt driven
mode, the BSP never touches it and printk() raises interrupts. Again:
this should go away
if pending irqs are cleared after masking in the initialization routine.
> Peter Dufault
> HD Associates, Inc.
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