From 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 27 Apr 2024 12:05:51 +0200 Subject: Adding upstream version 5.10.209. Signed-off-by: Daniel Baumann --- .../interrupt-controller/riscv,cpu-intc.txt | 52 ++++++++++++++++++++++ 1 file changed, 52 insertions(+) create mode 100644 Documentation/devicetree/bindings/interrupt-controller/riscv,cpu-intc.txt (limited to 'Documentation/devicetree/bindings/interrupt-controller/riscv,cpu-intc.txt') diff --git a/Documentation/devicetree/bindings/interrupt-controller/riscv,cpu-intc.txt b/Documentation/devicetree/bindings/interrupt-controller/riscv,cpu-intc.txt new file mode 100644 index 000000000..265b223cd --- /dev/null +++ b/Documentation/devicetree/bindings/interrupt-controller/riscv,cpu-intc.txt @@ -0,0 +1,52 @@ +RISC-V Hart-Level Interrupt Controller (HLIC) +--------------------------------------------- + +RISC-V cores include Control Status Registers (CSRs) which are local to each +CPU core (HART in RISC-V terminology) and can be read or written by software. +Some of these CSRs are used to control local interrupts connected to the core. +Every interrupt is ultimately routed through a hart's HLIC before it +interrupts that hart. + +The RISC-V supervisor ISA manual specifies three interrupt sources that are +attached to every HLIC: software interrupts, the timer interrupt, and external +interrupts. Software interrupts are used to send IPIs between cores. The +timer interrupt comes from an architecturally mandated real-time timer that is +controlled via Supervisor Binary Interface (SBI) calls and CSR reads. External +interrupts connect all other device interrupts to the HLIC, which are routed +via the platform-level interrupt controller (PLIC). + +All RISC-V systems that conform to the supervisor ISA specification are +required to have a HLIC with these three interrupt sources present. Since the +interrupt map is defined by the ISA it's not listed in the HLIC's device tree +entry, though external interrupt controllers (like the PLIC, for example) will +need to define how their interrupts map to the relevant HLICs. This means +a PLIC interrupt property will typically list the HLICs for all present HARTs +in the system. + +Required properties: +- compatible : "riscv,cpu-intc" +- #interrupt-cells : should be <1>. The interrupt sources are defined by the + RISC-V supervisor ISA manual, with only the following three interrupts being + defined for supervisor mode: + - Source 1 is the supervisor software interrupt, which can be sent by an SBI + call and is reserved for use by software. + - Source 5 is the supervisor timer interrupt, which can be configured by + SBI calls and implements a one-shot timer. + - Source 9 is the supervisor external interrupt, which chains to all other + device interrupts. +- interrupt-controller : Identifies the node as an interrupt controller + +Furthermore, this interrupt-controller MUST be embedded inside the cpu +definition of the hart whose CSRs control these local interrupts. + +An example device tree entry for a HLIC is show below. + + cpu1: cpu@1 { + compatible = "riscv"; + ... + cpu1-intc: interrupt-controller { + #interrupt-cells = <1>; + compatible = "sifive,fu540-c000-cpu-intc", "riscv,cpu-intc"; + interrupt-controller; + }; + }; -- cgit v1.2.3