mvme2604 confidence test.

gregory.menke at gregory.menke at
Tue Sep 27 21:38:41 UTC 2005

"Joel Sherrill <joel at>" <joel.sherrill at> writes:
 > gregory.menke at wrote:
 > > rtwas writes:
 > >  > Hello,
 > >  > 
 > >  > Question: What does this mean "pci : Interrupt routing not available for
 > >  > this bsp"?
 > >  > 
 > > 
 > > The bsp is not aware of how PCI bus interrupt lines are mapped to the interrupt controller interrupt lines.
 > > 
 > And... do tell more :)
 > The message is printed in libbsp/powerpc/shared/startup/bspstart.c
 > based upon calling motorolaIntMap(myBoard). myBoard is set earlier to 
 > the return value from getMotorolaBoard().
 > The code in libbsp/powerpc/shared/motorola must be enhanced to
 > recognize the board and pick the right interrupt map.  The interrupt
 > map table might have to be added.
 > Richard and I did the mvme2100 version in here.  The board has to be
 > recognized and there needs to be a minimal interrupt map.
 > Nothing too terrible to pull out of the board manual.  :)
 > You are getting there... don't stop yet.

Sorry sent too fast- stupid Mac keyboard I keep hitting 2 control C's...
This message too.  Macs make great Linux boxes but turning the left
apple button into a middle click & trying to compose email with vm in
emacs can be troublesome if you hit the wrong keys by accident...


the "swizzle" table- named from Linux, contains the mappings of the 4
PCI interrupt lines to the local board's interrupt controller.  The
vector space inside RTEMS maps all the interrupt controller inputs, so
the swizzle table is there to relate the PCI lines to the vector space.

As the final step in prepping the PCI hardware, the motorola_shared pci
routines computes the interrupt vector associated with each device using
the swizzle table & stores the vector in the device's pci config space.
If a driver or app software wants to use the device later, it just reads
out the interrupt vector and uses it directly.

PCI makes the swizzling necessary because the interrupt lines are
assigned "mod 4" to the slots- slot 1 gets int a, slot 2 gets int b,
slot 5 gets int a again, etc.. and pci bridges also rotate the interrupt
assignments.  The idea is to spread the interrupts over the 4 lines
rather than concentrate all the interrupts on one.

Onboard peripherals (even PCI ones) will often be either hardwired or
pre-configured with their interrupt info by the rom monitor.  But the
rom monitor may not handle devices down past the pci bridges.  There is
an argument in favor of that...


More information about the users mailing list