On Thu, May 08, 2003 at 08:08:56PM +0000, Kent Borg wrote: > > I am trying to understand "kinda shared" interrupts. > > There are various interrupts in my not-yet-released CPU, and I have > interrupt code that knows how to talk to them. So far so good. I > also have an external interrupt controller that groups together 18 > external interrupt sources and sends them in one CPU pin. This > external controller has a register for enabling interrupts, and a > register for status/acknowledge. Pretty standard. > > The CPU code doesn't know about the external controller. It seems > silly to rewrite the CPU-specific interrput code to accommodate this > board-specific detail (besides then my code won't match Dale's). So I > figure I tell the kernel I am doing shared interrupts. > > So where do I enable, disable, and acknowledge these external bits? > Specifically, I am trying to get a couple of serial ports working. I > can put conditional code in serial.c startup() to enable these > interrupts, but how do I know which serial port? Add a conditionally > compiled sub-IRQ number to serial_state structure? > > Is there a cleaner way?
Create and register a board-specific interrupt driver. Assign it a range of irqs (non-conflicting with the main interrupt driver). When called with an irq outside its range, the board-specific driver routines forward the call to the main driver. The board-specific driver does a request_irq at init time for the one main irq it is multiplexing. -Dale ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
