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Texas Instruments K3 Interrupt Router
=====================================
The Interrupt Router (INTR) module provides a mechanism to mux M
interrupt inputs to N interrupt outputs, where all M inputs are selectable
to be driven per N output. An Interrupt Router can either handle edge triggered
or level triggered interrupts and that is fixed in hardware.
Interrupt Router
+----------------------+
| Inputs Outputs |
+-------+ | +------+ +-----+ |
| GPIO |----------->| | irq0 | | 0 | | Host IRQ
+-------+ | +------+ +-----+ | controller
| . . | +-------+
+-------+ | . . |----->| IRQ |
| INTA |----------->| . . | +-------+
+-------+ | . +-----+ |
| +------+ | N | |
| | irqM | +-----+ |
| +------+ |
| |
+----------------------+
There is one register per output (MUXCNTL_N) that controls the selection.
Configuration of these MUXCNTL_N registers is done by a system controller
(like the Device Memory and Security Controller on K3 AM654 SoC). System
controller will keep track of the used and unused registers within the Router.
Driver should request the system controller to get the range of GIC IRQs
assigned to the requesting hosts. It is the drivers responsibility to keep
track of Host IRQs.
Communication between the host processor running an OS and the system
controller happens through a protocol called TI System Control Interface
(TISCI protocol). For more details refer:
Documentation/devicetree/bindings/arm/keystone/ti,sci.txt
TISCI Interrupt Router Node:
----------------------------
Required Properties:
- compatible: Must be "ti,sci-intr".
- ti,intr-trigger-type: Should be one of the following:
1: If intr supports edge triggered interrupts.
4: If intr supports level triggered interrupts.
- interrupt-controller: Identifies the node as an interrupt controller
- #interrupt-cells: Specifies the number of cells needed to encode an
interrupt source. The value should be 1.
First cell should contain interrupt router input number
as specified by hardware.
- ti,sci: Phandle to TI-SCI compatible System controller node.
- ti,sci-dev-id: TISCI device id of interrupt controller.
- ti,interrupt-ranges: Set of triplets containing ranges that convert
the INTR output interrupt numbers to parent's
interrupt number. Each triplet has following entries:
- First entry specifies the base for intr output irq
- Second entry specifies the base for parent irqs
- Third entry specifies the limit
For more details on TISCI IRQ resource management refer:
https://downloads.ti.com/tisci/esd/latest/2_tisci_msgs/rm/rm_irq.html
Example:
--------
The following example demonstrates both interrupt router node and the consumer
node(main gpio) on the AM654 SoC:
main_gpio_intr: interrupt-controller0 {
compatible = "ti,sci-intr";
ti,intr-trigger-type = <1>;
interrupt-controller;
interrupt-parent = <&gic500>;
#interrupt-cells = <1>;
ti,sci = <&dmsc>;
ti,sci-dev-id = <131>;
ti,interrupt-ranges = <0 360 32>;
};
main_gpio0: gpio@600000 {
...
interrupt-parent = <&main_gpio_intr>;
interrupts = <192>, <193>, <194>, <195>, <196>, <197>;
...
};
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