PCI: xgene: Add APM X-Gene PCIe driver

Add the AppliedMicro X-Gene SOC PCIe host controller driver.  The X-Gene
PCIe controller supports up to 8 lanes and GEN3 speed.  The X-Gene SOC
supports up to 5 PCIe ports.

[bhelgaas: folded in MAINTAINERS and bindings updates]
Tested-by: Ming Lei <ming.lei@canonical.com>
Tested-by: Dann Frazier <dann.frazier@canonical.com>
Signed-off-by: Tanmay Inamdar <tinamdar@apm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Liviu Dudau <Liviu.Dudau@arm.com> (driver)

Documentation/devicetree/bindings/pci/xgene-pci.txt

+* AppliedMicro X-Gene PCIe interface
+
+Required properties:
+- device_type: set to "pci"
+- compatible: should contain "apm,xgene-pcie" to identify the core.
+- reg: A list of physical base address and length for each set of controller
+       registers. Must contain an entry for each entry in the reg-names
+       property.
+- reg-names: Must include the following entries:
+  "csr": controller configuration registers.
+  "cfg": pcie configuration space registers.
+- #address-cells: set to <3>
+- #size-cells: set to <2>
+- ranges: ranges for the outbound memory, I/O regions.
+- dma-ranges: ranges for the inbound memory 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.
+- clocks: from common clock binding: handle to pci clock.
+
+Optional properties:
+- status: Either "ok" or "disabled".
+- dma-coherent: Present if dma operations are coherent
+
+Example:
+
+SoC specific DT Entry:
+
+	pcie0: pcie@1f2b0000 {
+		status = "disabled";
+		device_type = "pci";
+		compatible = "apm,xgene-storm-pcie", "apm,xgene-pcie";
+		#interrupt-cells = <1>;
+		#size-cells = <2>;
+		#address-cells = <3>;
+		reg = < 0x00 0x1f2b0000 0x0 0x00010000   /* Controller registers */
+			0xe0 0xd0000000 0x0 0x00040000>; /* PCI config space */
+		reg-names = "csr", "cfg";
+		ranges = <0x01000000 0x00 0x00000000 0xe0 0x10000000 0x00 0x00010000   /* io */
+			  0x02000000 0x00 0x80000000 0xe1 0x80000000 0x00 0x80000000>; /* mem */
+		dma-ranges = <0x42000000 0x80 0x00000000 0x80 0x00000000 0x00 0x80000000
+			      0x42000000 0x00 0x00000000 0x00 0x00000000 0x80 0x00000000>;
+		interrupt-map-mask = <0x0 0x0 0x0 0x7>;
+		interrupt-map = <0x0 0x0 0x0 0x1 &gic 0x0 0xc2 0x1
+				 0x0 0x0 0x0 0x2 &gic 0x0 0xc3 0x1
+				 0x0 0x0 0x0 0x3 &gic 0x0 0xc4 0x1
+				 0x0 0x0 0x0 0x4 &gic 0x0 0xc5 0x1>;
+		dma-coherent;
+		clocks = <&pcie0clk 0>;
+	};
+
+
+Board specific DT Entry:
+	&pcie0 {
+		status = "ok";
+	};

MAINTAINERS

@@ -6868,6 +6868,14 @@ F:	include/linux/pci*
 F:	arch/x86/pci/
 F:	arch/x86/kernel/quirks.c
 
+PCI DRIVER FOR APPLIEDMICRO XGENE
+M:	Tanmay Inamdar <tinamdar@apm.com>
+L:	linux-pci@vger.kernel.org
+L:	linux-arm-kernel@lists.infradead.org
+S:	Maintained
+F:	Documentation/devicetree/bindings/pci/xgene-pci.txt
+F:	drivers/pci/host/pci-xgene.c
+
 PCI DRIVER FOR IMX6
 M:	Richard Zhu <r65037@freescale.com>
 M:	Shawn Guo <shawn.guo@freescale.com>

drivers/pci/host/Kconfig

@@ -63,4 +63,14 @@ config PCIE_SPEAR13XX
 	help
 	  Say Y here if you want PCIe support on SPEAr13XX SoCs.
 
+config PCI_XGENE
+	bool "X-Gene PCIe controller"
+	depends on ARCH_XGENE
+	depends on OF
+	select PCIEPORTBUS
+	help
+	  Say Y here if you want internal PCI support on APM X-Gene SoC.
+	  There are 5 internal PCIe ports available. Each port is GEN3 capable
+	  and have varied lanes from x1 to x8.
+
 endmenu

drivers/pci/host/Makefile

@@ -8,3 +8,4 @@ obj-$(CONFIG_PCI_RCAR_GEN2) += pci-rcar-gen2.o
 obj-$(CONFIG_PCI_RCAR_GEN2_PCIE) += pcie-rcar.o
 obj-$(CONFIG_PCI_HOST_GENERIC) += pci-host-generic.o
 obj-$(CONFIG_PCIE_SPEAR13XX) += pcie-spear13xx.o
+obj-$(CONFIG_PCI_XGENE) += pci-xgene.o