MSM PCI express endpoint

Required properties:
  - compatible: should be "qcom,pcie-ep".
  - reg: should contain PCIe register maps.
  - reg-names: indicates various resources passed to driver by name.
		Should be "msi", "dm_core", "elbi", "parf", "phy", "mmio",
		"tcsr_pcie_perst_en".
		These correspond to different modules within the PCIe domain.
  - #address-cells: Should provide a value of 0.
  - interrupt-parent: Should be the PCIe device node itself here.
  - interrupts: Should be in the format <0 1 2> and it is an index to the
		interrupt-map that contains PCIe related interrupts.
  - #interrupt-cells: Should provide a value of 1.
  - #interrupt-map-mask: should provide a value of 0xffffffff.
  - interrupt-map:  Must create mapping for the number of interrupts
		    that are defined in above interrupts property.
		    For PCIe device node, it should define 6 mappings for
		    the corresponding PCIe interrupts supporting the
		    specification.
  - interrupt-names: indicates interrupts passed to driver by name.
		     Should be "int_pm_turnoff", "int_dstate_change",
				"int_l1sub_timeout", "int_link_up",
				"int_link_down", "int_bridge_flush_n".
  - perst-gpio: PERST GPIO specified by PCIe spec.
  - wake-gpio: WAKE GPIO specified by PCIe spec.
  - clkreq-gpio: CLKREQ GPIO specified by PCIe spec.
  - <supply-name>-supply: phandle to the regulator device tree node.
    Refer to the schematics for the corresponding voltage regulators.
    vreg-1.8-supply: phandle to the analog supply for the PCIe controller.
    vreg-0.9-supply: phandle to the analog supply for the PCIe controller.

Optional Properties:
  - qcom,<supply-name>-voltage-level: specifies voltage levels for supply.
    Should be specified in pairs (max, min, optimal), units uV.
  - qcom,vreg-mx-voltage-level: Support PCIe Gen4 on sdxlemur by scaling MX to
    appropriate voltage.
  - clock-names: list of names of clock inputs.
		     Should be "pcie_pipe_clk",
				"pcie_aux_clk", "pcie_cfg_ahb_clk",
				"pcie_mstr_axi_clk", "pcie_slv_axi_clk",
				"pcie_ldo";
  - max-clock-frequency-hz: list of the maximum operating frequencies stored
				in the same order of clock names;
  - resets: reset specifier pair consists of phandle for the reset controller
    and reset lines used by this controller.
  - reset-names: reset signal names sorted in the same order as the property
    of resets.
  - qcom,pcie-phy-ver: version of PCIe PHY.
  - qcom,phy-init: The initialization sequence to bring up the PCIe PHY.
    Should be specified in groups (offset, value, delay, direction).
  - qcom,phy-status-reg: Register offset for PHY status.
  - qcom,phy-status-reg2: For sdxprairie and above use only
    qcom,phy-status-reg2 as register offset for PHY status.
  - qcom,dbi-base-reg: Register offset for DBI base address.
  - qcom,slv-space-reg: Register offset for slave address space size.
  - qcom,pcie-vendor-id: Vendor id to be written to the Vendor ID register.
  - qcom,pcie-device-id: Device id to be written to the Device ID register.
  - qcom,pcie-link-speed: generation of PCIe link speed. The value could be
    1, 2 or 3.
  - qcom,pcie-active-config: boolean type; active configuration of PCIe
    addressing.
  - qcom,pcie-edma: boolean type; edma usage for PCIe.
  - qcom,pcie-aggregated-irq: boolean type; interrupts are aggregated.
  - qcom,pcie-mhi-a7-irq: boolean type; MHI a7 has separate irq.
  - qcom,pcie-perst-enum: Link enumeration will be triggered by PERST
    deassertion.
  - qcom,tcsr-not-supported: TCSR pcie perst is not supported.
  - mdm2apstatus-gpio: GPIO used by PCIe endpoint side to notify the host side.
  - qcom,pcie-m2-autonomous: Enable L1ss sleep/exit to support M2 autonomous mode.
  - qcom,mhi-soc-reset-offset: AXI register offset to initiate a SOC reset.

Example:

	pcie_ep: qcom,pcie@bfffd000 {
		compatible = "qcom,pcie-ep";

		reg = <0xbfffd000 0x1000>,
			<0xbfffe000 0x1000>,
			<0xbffff000 0x1000>,
			<0xfc520000 0x2000>,
			<0xfc526000 0x1000>,
			<0xfc527000 0x1000>,
			<0x01fcb000 0x1000>;

		reg-names = "msi", "dm_core", "elbi", "parf", "phy", "mmio",
				"tcsr_pcie_perst";

		#address-cells = <0>;
		interrupt-parent = <&pcie_ep>;
		interrupts = <0 1 2 3 4 5>;
		#interrupt-cells = <1>;
		interrupt-map-mask = <0xffffffff>;
		interrupt-map = <0 &intc 0 44 0
				1 &intc 0 46 0
				2 &intc 0 47 0
				3 &intc 0 50 0
				4 &intc 0 51 0
				5 &intc 0 52 0>;
		interrupt-names = "int_pm_turnoff", "int_dstate_change",
				"int_l1sub_timeout", "int_link_up",
				"int_link_down", "int_bridge_flush_n";

		perst-gpio = <&msmgpio 65 0>;
		wake-gpio = <&msmgpio 61 0>;
		clkreq-gpio = <&msmgpio 64 0>;
		mdm2apstatus-gpio = <&tlmm_pinmux 16 0>;

		gdsc-vdd-supply = <&gdsc_pcie_0>;
		vreg-1.8-supply = <&pmd9635_l8>;
		vreg-0.9-supply = <&pmd9635_l4>;

		qcom,vreg-1.8-voltage-level = <1800000 1800000 1000>;
		qcom,vreg-0.9-voltage-level = <950000 950000 24000>;

		clock-names = "pcie_pipe_clk",
				"pcie_aux_clk", "pcie_cfg_ahb_clk",
				"pcie_mstr_axi_clk", "pcie_slv_axi_clk",
				"pcie_ldo";
		max-clock-frequency-hz = <62500000>, <1000000>,
						<0>, <0>, <0>, <0>;

		resets = <&clock_gcc GCC_PCIE_BCR>,
			<&clock_gcc GCC_PCIE_PHY_BCR>;

		reset-names = "pcie_core_reset", "pcie_phy_reset";

		qcom,pcie-link-speed = <1>;
		qcom,pcie-active-config;
		qcom,pcie-aggregated-irq;
		qcom,pcie-mhi-a7-irq;
		qcom,pcie-perst-enum;
		qcom,phy-status-reg = <0x728>;
		qcom,dbi-base-reg = <0x168>;
		qcom,slv-space-reg = <0x16c>;

		qcom,phy-init = <0x604 0x03 0x0 0x1
					0x048 0x08 0x0 0x1
					0x64c 0x4d 0x0 0x1
					0x600 0x00 0x0 0x1
					0x608 0x03 0x0 0x1>;
	};
