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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
commit | 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch) | |
tree | a94efe259b9009378be6d90eb30d2b019d95c194 /Documentation/devicetree/bindings/interrupt-controller/riscv,cpu-intc.txt | |
parent | Initial commit. (diff) | |
download | linux-430c2fc249ea5c0536abd21c23382884005c9093.tar.xz linux-430c2fc249ea5c0536abd21c23382884005c9093.zip |
Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'Documentation/devicetree/bindings/interrupt-controller/riscv,cpu-intc.txt')
-rw-r--r-- | Documentation/devicetree/bindings/interrupt-controller/riscv,cpu-intc.txt | 52 |
1 files changed, 52 insertions, 0 deletions
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; + }; + }; |