On Sun, Sep 06, 2009 at 01:06:41PM +0200, Sebastian Andrzej Siewior wrote: > irq_of_parse_and_map() creates a mapping between the hardware irq number > as specified in the device tree and the linux number (virq) which is > used within the linux api in request_irq() for instance. > irq_of_parse_and_map() is essential to create a mapping between those > two. The interrupt controller on the MPC8555 (mpic) specifies the first > few interrupt numbers as external sources followed by internal sources. > Now, during the init sequenze of the mpic every interrupt source > (internal and external) becomes its uniqe vector number which identifies > the source by a number. This number is the hardware interrupt number > i.e. that thing in the device tree. The init sequence is a for loop > which starts at 0 for the first interrupt source which happens to be > external interrupt 0, 1 for external interrupt 1 and so on. At the time > it reaches the first internal interrupt source the vector number is 16. > That's why you always have an offset of 16 between every internal > interupt source number in the MPC855ERM document and those weired > numbers in the device tree :)
This seems to be a common point of confusion -- we should probably put something in the dts bindings that explains it. Am I correct in assuming that this particular internal/external split is Freescale-specific and not a general OpenPIC thing? -Scott _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
