Felipe, On Wed, 30 Dec 2015, Felipe Balbi wrote: > Thomas Gleixner <t...@linutronix.de> writes: > > - Is there a "mapping" block between PRUSS and the host interrupt > > controller > > or is this "mapping" block part of PRUSS? > > The description in TRM is a bit "poor", but from what I can gather, the > mapping is done on an interrupt controller inside the PRUSS. However, > Linux is the one who's got the driver for that INTC (well, Linux will be > the one with the soft ethernet/uart/whatever IP to talk to). All of its > (INTC's) registers are memory mapped to the ARM side.
Ok. And the INTC registers include the "mapping" configuration, right? > > - We all know how well shared interrupts work. Is there a point of > > supporting > > 64 interrupts when you only have 10 irq lines available? > > I'm looking at these 64 events more like MSI kind of events. It's just Well, that's fine to look at them this way, but they will end up shared no matter what. > that the events themselves can be routed to any of the 10 available HW > IRQ lines. > > > - I assume that the PRUSS interrupt mapping is more or less a question of > > the > > firmware implementation. So you either have a fixed association in the > > firmware which is reflected in the DT description of the IP block or you > > need an interface to tell the PRUSS firmware which event it should map to > > which irq line. Is there actually a value in doing the latter? > > right, I'd say the mapping is pretty static. Unless Suman has some extra > information which I don't. I guess the question was really to see if > there was an easy way for doing this so we don't have to mess with DTS > for every other FW and their neighbor. Well, you will need information about every other firmware simply because you need to know which events the firmware is actually using and what the purpose of the particular event is. Assume you have a simple uart with 3 events (RX, TX, status). So how will the firmware tell you which event is which? You have a few options: 1) DT + fixed mapping scheme: Describe the PRUSS event number in DT and have a fixed mapping scheme like the one you mentioned evt0 -> irq0 ..... 2) DT + DT mapping scheme Describe the PRUSS event number in DT and describe the mapping scheme in DT as well 3) DT + dynamic mapping scheme Describe the PRUSS event number in DT and let your interrupt controller associate the irq number dynamically. That's kind of similar to MSI with the exception that it needs to support shared interrupts. 4) Fully dynamic association Have a query interface to the firmware which tells you which event it uses for which particular purpose (RX, TX ...) and then establish a dynamic mapping to one of the interrupts. Not sure which level of complexity you want :) Thanks, tglx -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html