Sarnath Kannan wrote: > > The reason for assigning vector of 16 to PCI > interrupts is because each entry in the "Interrupt Source" is 32 bytes long, > 16 * 32 = 512 = 0x200 > which equals the difference in offsets between > the std openPIC layout and EPIC register layout. > This 16 has got NOTHING TO DO with NUM_8259_INTERRUPTS. > But Mvista code seems to assume that this feature > is because of NUM_8259_INTERRUPTS. ( See the > #define for SANDPOINT_SIO_IRQ ).
... unless the register layout for the EPIC was designed to allow an external i8259 to be inserted into the gap, which ISTR is done on some boards. I don't know for sure and I might be completely confused about that, but there must have been some reason why the EPIC was designed like that. Just throwing that idea into the pot... - Andrew -- Perfection is reached, not when there is no longer anything to add, but when there is no longer anything to take away. - Antoine de Saint-Exupery ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
