On Thu, Jul 18, 2013 at 8:56 PM, Nishanth Menon <nm@xxxxxx> wrote: > I carry forward my TI internal objection to this approach: It is actually a very good sign of FOSS-maturity that you as a company take unresolved architectural issues to the community. Kudos! > Lets see what happens as a result of this: > > https://patchwork.kernel.org/patch/2825148/ (introducing DTS for DRA7) > uart1 to uart6 is defined. while in fact 10 uarts exist on IP block. > uart1: serial@4806a000 { > <snip> > + interrupts = <0 72 0x4>; > Assumes that GIC interrupt by default mapping used. So introducing this inbetween the GIC lines and its actual device IRQ lines inevitably means that the GIC three-cell concept is completely ill-devised to handle this. For routing IRQs, I think the proper solution would be to use a cascaded struct irqchip, which in turn contains an irqdomain translation to remux the signal onto the GIC inputs. I.e. the interrupt-controller given to that serial would be the crossbar irqchip, and that in turn will hog and allocate apropriate lines from the gic to it would probably itself list *all* the IRQs of the GIC as "its" IRQs. We already have plenty of cascading irqchips such as GPIO controller providing IRQs, just that they only multiplex on a single GIC line instead of the whole lot. Mock example: intc: interrupt-controller@0 { compatible = "arm,cortex-a9-gic"; #interrupt-cells = <3>; #address-cells = <1>; interrupt-controller; reg = ...; }; crossbar: crossbar@0 { compatible = "..."; interrupt-controller; #interrupt-cells = <1>; interrupt-parent = <&intc>; interrupts = <0 0 IRQ_TYPE_LEVEL_HIGH>, <0 1 IRQ_TYPE_LEVEL_HIGH>, <0 2 IRQ_TYPE_LEVEL_HIGH>, .... <0 n IRQ_TYPE_LEVEL_HIGH>; }; uart0: serial@0 { compatible = "..."; interrupt-parent = <&crossbar>; interrupts = <1234>; }; Maybe the interrupts provided from crossbar cannot even be specified by a number, maybe a line name need to be used or so. I don't know the particulars. Whether this as a whole is a good idea, I don't know, but you would have to go about it something like this. What happens if there is no line to mux in a certain IRQ? Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
