diff options
Diffstat (limited to 'Documentation/devicetree/bindings/riscv/cpus.txt')
| -rw-r--r-- | Documentation/devicetree/bindings/riscv/cpus.txt | 162 |
1 files changed, 0 insertions, 162 deletions
diff --git a/Documentation/devicetree/bindings/riscv/cpus.txt b/Documentation/devicetree/bindings/riscv/cpus.txt deleted file mode 100644 index adf7b7af5dc3..000000000000 --- a/Documentation/devicetree/bindings/riscv/cpus.txt +++ /dev/null @@ -1,162 +0,0 @@ -=================== -RISC-V CPU Bindings -=================== - -The device tree allows to describe the layout of CPUs in a system through -the "cpus" node, which in turn contains a number of subnodes (ie "cpu") -defining properties for every cpu. - -Bindings for CPU nodes follow the Devicetree Specification, available from: - -https://www.devicetree.org/specifications/ - -with updates for 32-bit and 64-bit RISC-V systems provided in this document. - -=========== -Terminology -=========== - -This document uses some terminology common to the RISC-V community that is not -widely used, the definitions of which are listed here: - -* hart: A hardware execution context, which contains all the state mandated by - the RISC-V ISA: a PC and some registers. This terminology is designed to - disambiguate software's view of execution contexts from any particular - microarchitectural implementation strategy. For example, my Intel laptop is - described as having one socket with two cores, each of which has two hyper - threads. Therefore this system has four harts. - -===================================== -cpus and cpu node bindings definition -===================================== - -The RISC-V architecture, in accordance with the Devicetree Specification, -requires the cpus and cpu nodes to be present and contain the properties -described below. - -- cpus node - - Description: Container of cpu nodes - - The node name must be "cpus". - - A cpus node must define the following properties: - - - #address-cells - Usage: required - Value type: <u32> - Definition: must be set to 1 - - #size-cells - Usage: required - Value type: <u32> - Definition: must be set to 0 - -- cpu node - - Description: Describes a hart context - - PROPERTIES - - - device_type - Usage: required - Value type: <string> - Definition: must be "cpu" - - reg - Usage: required - Value type: <u32> - Definition: The hart ID of this CPU node - - compatible: - Usage: required - Value type: <stringlist> - Definition: must contain "riscv", may contain one of - "sifive,rocket0" - - mmu-type: - Usage: optional - Value type: <string> - Definition: Specifies the CPU's MMU type. Possible values are - "riscv,sv32" - "riscv,sv39" - "riscv,sv48" - - riscv,isa: - Usage: required - Value type: <string> - Definition: Contains the RISC-V ISA string of this hart. These - ISA strings are defined by the RISC-V ISA manual. - -Example: SiFive Freedom U540G Development Kit ---------------------------------------------- - -This system contains two harts: a hart marked as disabled that's used for -low-level system tasks and should be ignored by Linux, and a second hart that -Linux is allowed to run on. - - cpus { - #address-cells = <1>; - #size-cells = <0>; - timebase-frequency = <1000000>; - cpu@0 { - clock-frequency = <1600000000>; - compatible = "sifive,rocket0", "riscv"; - device_type = "cpu"; - i-cache-block-size = <64>; - i-cache-sets = <128>; - i-cache-size = <16384>; - next-level-cache = <&L15 &L0>; - reg = <0>; - riscv,isa = "rv64imac"; - status = "disabled"; - L10: interrupt-controller { - #interrupt-cells = <1>; - compatible = "riscv,cpu-intc"; - interrupt-controller; - }; - }; - cpu@1 { - clock-frequency = <1600000000>; - compatible = "sifive,rocket0", "riscv"; - d-cache-block-size = <64>; - d-cache-sets = <64>; - d-cache-size = <32768>; - d-tlb-sets = <1>; - d-tlb-size = <32>; - device_type = "cpu"; - i-cache-block-size = <64>; - i-cache-sets = <64>; - i-cache-size = <32768>; - i-tlb-sets = <1>; - i-tlb-size = <32>; - mmu-type = "riscv,sv39"; - next-level-cache = <&L15 &L0>; - reg = <1>; - riscv,isa = "rv64imafdc"; - status = "okay"; - tlb-split; - L13: interrupt-controller { - #interrupt-cells = <1>; - compatible = "riscv,cpu-intc"; - interrupt-controller; - }; - }; - }; - -Example: Spike ISA Simulator with 1 Hart ----------------------------------------- - -This device tree matches the Spike ISA golden model as run with `spike -p1`. - - cpus { - cpu@0 { - device_type = "cpu"; - reg = <0x00000000>; - status = "okay"; - compatible = "riscv"; - riscv,isa = "rv64imafdc"; - mmu-type = "riscv,sv48"; - clock-frequency = <0x3b9aca00>; - interrupt-controller { - #interrupt-cells = <0x00000001>; - interrupt-controller; - compatible = "riscv,cpu-intc"; - } - } - } |