Hi, We are trying to write a driver for an interrupt controller (actually more of a crossbar) for an ARM-based SoC. This IRQ crossbar has 128 inputs and 24 outputs, the outputs are connected directly to the GIC. The idea is that the GIC handles everything, and just request a mapping from an IRQ number (0...127, from a device's DT entry) into one of its 24 input lines.
By looking at current code (4.7-rc1) there seems to be a driver (drivers/irqchip/irq-crossbar.c) that provides similar functionality. The driver uses hierarchical irq domains (since commit 783d31863fb8 "irqchip: crossbar: Convert dra7 crossbar to stacked domains") which we believe we don't need because the only controller is the GIC. However the API used previously, register_routable_domain_ops(), was removed with commit a5561c3e845c "irqchip: gic: Get rid of routable domain". Trying to use the driver with hierarchical domains (after modifications for our SoC), results on the kernel being blocked at some point: [ 0.041524] ThumbEE CPU extension supported. [ 0.041589] Registering SWP/SWPB emulation handler [ 0.052022] Freeing unused kernel memory: 12364K (c029b000 - c0eae000) [ 0.074084] random: dbus-uuidgen urandom read with 0 bits of entropy available We've put logs on the different domain_ops calls (alloc, free, translate) but they are not called, even if the DT is supposed to tell devices to take interrupts from this controller (*). Do you have suggestions on what APIs should be used, further reading/examples and/or pointers on how debug this (logs to enable, things to look for, etc.)? Thanks in advance. Best regards, Sebastian (*): here's the diff on our DT: --- tango4-common.dtsi 2016-06-10 16:23:08.244246017 +0200 +++ tangox_irqv2-common.dtsi 2016-06-10 16:24:01.212588737 +0200 @@ -47,7 +47,7 @@ soc { compatible = "simple-bus"; - interrupt-parent = <&irq0>; + interrupt-parent = <&irq_mux>; #address-cells = <1>; #size-cells = <1>; ranges; @@ -75,7 +75,7 @@ uart: serial@10700 { compatible = "ralink,rt2880-uart"; reg = <0x10700 0x30>; - interrupts = <1 IRQ_TYPE_LEVEL_HIGH>; + interrupts = <GIC_SPI 1 IRQ_TYPE_LEVEL_HIGH>; clock-frequency = <7372800>; reg-shift = <2>; }; @@ -83,10 +83,11 @@ eth0: ethernet@26000 { compatible = "sigma,smp8734-ethernet"; reg = <0x26000 0x800>; - interrupts = <38 IRQ_TYPE_LEVEL_HIGH>; + interrupts = <GIC_SPI 38 IRQ_TYPE_LEVEL_HIGH>; clocks = <&clkgen 1>; }; +#if 0 intc: interrupt-controller@6e000 { compatible = "sigma,smp8642-intc"; reg = <0x6e000 0x400>; @@ -117,5 +118,16 @@ interrupts = <GIC_SPI 4 IRQ_TYPE_LEVEL_HIGH>; }; }; +#else + irq_mux: irq_mux@6f800 { + compatible = "sigma,smp-irq-mux"; + reg = <0x6f800 0x400>; + interrupt-controller; + interrupt-parent = <&gic>; + irqs-reserved = <2 3 4 125 126 127>; + }; + +#endif + }; };