linux/Documentation/devicetree/bindings/pci/host-generic-pci.yaml

# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
%YAML 1.2
---
$id: http://devicetree.org/schemas/pci/host-generic-pci.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#

title: Generic PCI host controller

maintainers:
  - Will Deacon <will@kernel.org>

description: |
  Firmware-initialised PCI host controllers and PCI emulations, such as the
  virtio-pci implementations found in kvmtool and other para-virtualised
  systems, do not require driver support for complexities such as regulator
  and clock management. In fact, the controller may not even require the
  configuration of a control interface by the operating system, instead
  presenting a set of fixed windows describing a subset of IO, Memory and
  Configuration Spaces.

  Configuration Space is assumed to be memory-mapped (as opposed to being
  accessed via an ioport) and laid out with a direct correspondence to the
  geography of a PCI bus address by concatenating the various components to
  form an offset.

  For CAM, this 24-bit offset is:

          cfg_offset(bus, device, function, register) =
                     bus << 16 | device << 11 | function << 8 | register

  While ECAM extends this by 4 bits to accommodate 4k of function space:

          cfg_offset(bus, device, function, register) =
                     bus << 20 | device << 15 | function << 12 | register  

properties:
  compatible:
    description: Depends on the layout of configuration space (CAM vs ECAM
      respectively). May also have more specific compatibles.
    oneOf:
      - description:
          PCIe host controller in Arm Juno based on PLDA XpressRICH3-AXI IP
        items:
          - const: arm,juno-r1-pcie
          - const: plda,xpressrich3-axi
          - const: pci-host-ecam-generic
      - description: |
          ThunderX PCI host controller for pass-1.x silicon

          Firmware-initialized PCI host controller to on-chip devices found on
          some Cavium ThunderX processors.  These devices have ECAM-based config
          access, but the BARs are all at fixed addresses.  We handle the fixed
          addresses by synthesizing Enhanced Allocation (EA) capabilities for
          these devices.          
        const: cavium,pci-host-thunder-ecam
      - description:
          Cavium ThunderX PEM firmware-initialized PCIe host controller
        const: cavium,pci-host-thunder-pem
      - description:
          HiSilicon Hip06/Hip07 PCIe host bridge in almost-ECAM mode. Some
          firmware places the host controller in a mode where it is ECAM
          compliant for all devices other than the root complex.
        enum:
          - hisilicon,hip06-pcie-ecam
          - hisilicon,hip07-pcie-ecam
      - description: |
          In some cases, firmware may already have configured the Synopsys
          DesignWare PCIe controller in RC mode with static ATU window mappings
          that cover all config, MMIO and I/O spaces in a [mostly] ECAM
          compatible fashion. In this case, there is no need for the OS to
          perform any low level setup of clocks, PHYs or device registers, nor
          is there any reason for the driver to reconfigure ATU windows for
          config and/or IO space accesses at runtime.

          In cases where the IP was synthesized with a minimum ATU window size
          of 64 KB, it cannot be supported by the generic ECAM driver, because
          it requires special config space accessors that filter accesses to
          device #1 and beyond on the first bus.          
        items:
          - enum:
              - marvell,armada8k-pcie-ecam
              - socionext,synquacer-pcie-ecam
          - const: snps,dw-pcie-ecam
      - description:
          CAM or ECAM compliant PCI host controllers without any quirks
        enum:
          - pci-host-cam-generic
          - pci-host-ecam-generic

  reg:
    description:
      The Configuration Space base address and size, as accessed from the parent
      bus. The base address corresponds to the first bus in the "bus-range"
      property. If no "bus-range" is specified, this will be bus 0 (the
      default). Some host controllers have a 2nd non-compliant address range,
      so 2 entries are allowed.
    minItems: 1
    maxItems: 2

  ranges:
    description:
      As described in IEEE Std 1275-1994, but must provide at least a
      definition of non-prefetchable memory. One or both of prefetchable Memory
      and IO Space may also be provided.
    minItems: 1
    maxItems: 3

  dma-coherent: true

required:
  - compatible
  - reg
  - ranges

allOf:
  - $ref: /schemas/pci/pci-bus.yaml#
  - if:
      properties:
        compatible:
          contains:
            const: arm,juno-r1-pcie
    then:
      required:
        - dma-coherent

  - if:
      properties:
        compatible:
          not:
            contains:
              enum:
                - cavium,pci-host-thunder-pem
                - hisilicon,hip06-pcie-ecam
                - hisilicon,hip07-pcie-ecam
    then:
      properties:
        reg:
          maxItems: 1

unevaluatedProperties: false

examples:
  - |

    bus {
        #address-cells = <2>;
        #size-cells = <2>;
        pcie@40000000 {
            compatible = "pci-host-cam-generic";
            device_type = "pci";
            #address-cells = <3>;
            #size-cells = <2>;
            bus-range = <0x0 0x1>;

            // CPU_PHYSICAL(2)  SIZE(2)
            reg = <0x0 0x40000000  0x0 0x1000000>;

            // BUS_ADDRESS(3)  CPU_PHYSICAL(2)  SIZE(2)
            ranges = <0x01000000 0x0 0x01000000  0x0 0x01000000  0x0 0x00010000>,
                     <0x02000000 0x0 0x41000000  0x0 0x41000000  0x0 0x3f000000>;

            #interrupt-cells = <0x1>;

            // PCI_DEVICE(3)  INT#(1)  CONTROLLER(PHANDLE)  CONTROLLER_DATA(3)
            interrupt-map = <   0x0 0x0 0x0  0x1  &gic  0x0 0x4 0x1>,
                            < 0x800 0x0 0x0  0x1  &gic  0x0 0x5 0x1>,
                            <0x1000 0x0 0x0  0x1  &gic  0x0 0x6 0x1>,
                            <0x1800 0x0 0x0  0x1  &gic  0x0 0x7 0x1>;

            // PCI_DEVICE(3)  INT#(1)
            interrupt-map-mask = <0xf800 0x0 0x0  0x7>;
        };
    };
...