On Thu, Nov 10, 2022 at 8:43 PM Anup Patel <apatel@xxxxxxxxxxxxxxxx> wrote: > > We add DT bindings document for RISC-V incoming MSI controller (IMSIC) > defined by the RISC-V advanced interrupt architecture (AIA) specification. > > Signed-off-by: Anup Patel <apatel@xxxxxxxxxxxxxxxx> > --- > .../interrupt-controller/riscv,imsic.yaml | 174 ++++++++++++++++++ > 1 file changed, 174 insertions(+) > create mode 100644 Documentation/devicetree/bindings/interrupt-controller/riscv,imsic.yaml > > diff --git a/Documentation/devicetree/bindings/interrupt-controller/riscv,imsic.yaml b/Documentation/devicetree/bindings/interrupt-controller/riscv,imsic.yaml > new file mode 100644 > index 000000000000..05106eb1955e > --- /dev/null > +++ b/Documentation/devicetree/bindings/interrupt-controller/riscv,imsic.yaml > @@ -0,0 +1,174 @@ > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) > +%YAML 1.2 > +--- > +$id: http://devicetree.org/schemas/interrupt-controller/riscv,imsic.yaml# > +$schema: http://devicetree.org/meta-schemas/core.yaml# > + > +title: RISC-V Incoming MSI Controller (IMSIC) > + > +maintainers: > + - Anup Patel <anup@xxxxxxxxxxxxxx> > + > +description: > + The RISC-V advanced interrupt architecture (AIA) defines a per-CPU incoming > + MSI controller (IMSIC) for handling MSIs in a RISC-V platform. The RISC-V > + AIA specification can be found at https://github.com/riscv/riscv-aia. > + > + The IMSIC is a per-CPU (or per-HART) device with separate interrupt file > + for each privilege level (machine or supervisor). The configuration of > + a IMSIC interrupt file is done using AIA CSRs and it also has a 4KB MMIO > + space to receive MSIs from devices. Each IMSIC interrupt file supports a > + fixed number of interrupt identities (to distinguish MSIs from devices) > + which is same for given privilege level across CPUs (or HARTs). > + > + The arrangement of IMSIC interrupt files in MMIO space of a RISC-V platform > + follows a particular scheme defined by the RISC-V AIA specification. A IMSIC > + group is a set of IMSIC interrupt files co-located in MMIO space and we can > + have multiple IMSIC groups (i.e. clusters, sockets, chiplets, etc) in a > + RISC-V platform. The MSI target address of a IMSIC interrupt file at given > + privilege level (machine or supervisor) encodes group index, HART index, > + and guest index (shown below). > + > + XLEN-1 >=24 12 0 > + | | | | > + ------------------------------------------------------------- > + |xxxxxx|Group Index|xxxxxxxxxxx|HART Index|Guest Index| 0 | > + ------------------------------------------------------------- > + > + The device tree of a RISC-V platform will have one IMSIC device tree node > + for each privilege level (machine or supervisor) which collectively describe > + IMSIC interrupt files at that privilege level across CPUs (or HARTs). > + > +allOf: > + - $ref: /schemas/interrupt-controller.yaml# > + > +properties: > + compatible: > + items: > + - enum: > + - vendor,chip-imsics > + - const: riscv,imsics > + > + reg: > + minItems: 1 > + maxItems: 128 > + description: > + Base address of each IMSIC group. > + > + interrupt-controller: true > + > + "#interrupt-cells": > + const: 0 > + > + msi-controller: true > + > + interrupts-extended: > + minItems: 1 > + maxItems: 32768 > + description: > + This property represents the set of CPUs (or HARTs) for which given > + device tree node describes the IMSIC interrupt files. Each node pointed > + to should be a riscv,cpu-intc node, which has a riscv node (i.e. RISC-V > + HART) as parent. > + > + riscv,num-ids: > + $ref: /schemas/types.yaml#/definitions/uint32 > + minimum: 63 > + maximum: 2047 > + description: > + Specifies how many interrupt identities are supported by IMSIC interrupt > + file. > + > + riscv,num-guest-ids: > + $ref: /schemas/types.yaml#/definitions/uint32 > + minimum: 63 > + maximum: 2047 > + description: > + Specifies how many interrupt identities are supported by IMSIC guest > + interrupt file. When not specified the number of interrupt identities > + supported by IMSIC guest file is assumed to be same as specified by > + the riscv,num-ids property. > + > + riscv,slow-ipi: > + type: boolean > + description: > + The presence of this property implies that software interrupts (i.e. > + IPIs) using IMSIC software injected MSIs is slower compared to other > + software interrupt mechanisms (such as SBI IPI) on the underlying > + RISC-V platform. > + > + riscv,guest-index-bits: > + minimum: 0 > + maximum: 7 > + description: > + Specifies number of guest index bits in the MSI target address. When > + not specified it is assumed to be 0. > + > + riscv,hart-index-bits: > + minimum: 0 > + maximum: 15 > + description: > + Specifies number of HART index bits in the MSI target address. When > + not specified it is estimated based on the interrupts-extended property. > + > + riscv,group-index-bits: > + minimum: 0 > + maximum: 7 > + description: > + Specifies number of group index bits in the MSI target address. When > + not specified it is assumed to be 0. > + > + riscv,group-index-shift: > + $ref: /schemas/types.yaml#/definitions/uint32 > + minimum: 24 > + maximum: 55 > + description: > + Specifies the least significant bit of the group index bits in the > + MSI target address. When not specified it is assumed to be 24. > + > +additionalProperties: false > + > +required: > + - compatible > + - reg > + - interrupt-controller > + - msi-controller > + - interrupts-extended > + - riscv,num-ids > + > +examples: > + - | > + // Example 1 (Machine-level IMSIC files with just one group): > + > + imsic_mlevel: interrupt-controller@24000000 { > + compatible = "vendor,chip-imsics", "riscv,imsics"; > + interrupts-extended = <&cpu1_intc 11>, > + <&cpu2_intc 11>, > + <&cpu3_intc 11>, > + <&cpu4_intc 11>; > + reg = <0x28000000 0x4000>; nit: /s/0x28000000/24000000 > + interrupt-controller; > + #interrupt-cells = <0>; > + msi-controller; > + riscv,num-ids = <127>; > + }; > + > + - | > + // Example 2 (Supervisor-level IMSIC files with two groups): > + > + imsic_slevel: interrupt-controller@28000000 { > + compatible = "vendor,chip-imsics", "riscv,imsics"; > + interrupts-extended = <&cpu1_intc 9>, > + <&cpu2_intc 9>, > + <&cpu3_intc 9>, > + <&cpu4_intc 9>; > + reg = <0x28000000 0x2000>, /* Group0 IMSICs */ > + <0x29000000 0x2000>; /* Group1 IMSICs */ > + interrupt-controller; > + #interrupt-cells = <0>; > + msi-controller; > + riscv,num-ids = <127>; > + riscv,group-index-bits = <1>; > + riscv,group-index-shift = <24>; > + }; > +... > -- > 2.34.1 > -- Regards, Atish
