linux-arkmicro/linux/Documentation/devicetree/bindings/pci/designware-pcie.txt

* Synopsys DesignWare PCIe interface

Required properties:
- compatible:
	"snps,dw-pcie" for RC mode;
	"snps,dw-pcie-ep" for EP mode;
- reg: Should contain the configuration address space.
- reg-names: Must be "config" for the PCIe configuration space.
    (The old way of getting the configuration address space from "ranges"
    is deprecated and should be avoided.)
- num-lanes: number of lanes to use
RC mode:
- #address-cells: set to <3>
- #size-cells: set to <2>
- device_type: set to "pci"
- ranges: ranges for the PCI memory and I/O regions
- #interrupt-cells: set to <1>
- interrupt-map-mask and interrupt-map: standard PCI
	properties to define the mapping of the PCIe interface to interrupt
	numbers.
EP mode:
- num-ib-windows: number of inbound address translation windows
- num-ob-windows: number of outbound address translation windows

Optional properties:
- num-lanes: number of lanes to use (this property should be specified unless
  the link is brought already up in BIOS)
- reset-gpio: GPIO pin number of power good signal
- clocks: Must contain an entry for each entry in clock-names.
	See ../clocks/clock-bindings.txt for details.
- clock-names: Must include the following entries:
	- "pcie"
	- "pcie_bus"
RC mode:
- num-viewport: number of view ports configured in hardware. If a platform
  does not specify it, the driver assumes 2.
- bus-range: PCI bus numbers covered (it is recommended for new devicetrees
  to specify this property, to keep backwards compatibility a range of
  0x00-0xff is assumed if not present)

EP mode:
- max-functions: maximum number of functions that can be configured

Example configuration:

	pcie: pcie@dfc00000 {
		compatible = "snps,dw-pcie";
		reg = <0xdfc00000 0x0001000>, /* IP registers */
		      <0xd0000000 0x0002000>; /* Configuration space */
		reg-names = "dbi", "config";
		#address-cells = <3>;
		#size-cells = <2>;
		device_type = "pci";
		ranges = <0x81000000 0 0x00000000 0xde000000 0 0x00010000
			  0x82000000 0 0xd0400000 0xd0400000 0 0x0d000000>;
		interrupts = <25>, <24>;
		#interrupt-cells = <1>;
		num-lanes = <1>;
	};
or
	pcie: pcie@dfc00000 {
		compatible = "snps,dw-pcie-ep";
		reg = <0xdfc00000 0x0001000>, /* IP registers 1 */
		      <0xdfc01000 0x0001000>, /* IP registers 2 */
		      <0xd0000000 0x2000000>; /* Configuration space */
		reg-names = "dbi", "dbi2", "addr_space";
		num-ib-windows = <6>;
		num-ob-windows = <2>;
		num-lanes = <1>;
	};