PCI: xilinx-nwl: Add support for Xilinx NWL PCIe Host Controller

Add PCIe Root Port driver for Xilinx PCIe NWL bridge IP.

[bhelgaas: wait for link like dw_pcie_wait_for_link(), simplify bitmap
error path, typos, whitespace, fold in Dan Carpenter's PTR_ERR() fix]
Signed-off-by: Bharat Kumar Gogada <bharatku@xilinx.com>
Signed-off-by: Ravi Kiran Gummaluri <rgummal@xilinx.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/pci/xilinx-nwl-pcie.txt

+* Xilinx NWL PCIe Root Port Bridge DT description
+
+Required properties:
+- compatible: Should contain "xlnx,nwl-pcie-2.11"
+- #address-cells: Address representation for root ports, set to <3>
+- #size-cells: Size representation for root ports, set to <2>
+- #interrupt-cells: specifies the number of cells needed to encode an
+	interrupt source. The value must be 1.
+- reg: Should contain Bridge, PCIe Controller registers location,
+	configuration space, and length
+- reg-names: Must include the following entries:
+	"breg": bridge registers
+	"pcireg": PCIe controller registers
+	"cfg": configuration space region
+- device_type: must be "pci"
+- interrupts: Should contain NWL PCIe interrupt
+- interrupt-names: Must include the following entries:
+	"msi1, msi0": interrupt asserted when MSI is received
+	"intx": interrupt asserted when a legacy interrupt is received
+	"misc": interrupt asserted when miscellaneous is received
+- interrupt-map-mask and interrupt-map: standard PCI properties to define the
+	mapping of the PCI interface to interrupt numbers.
+- ranges: ranges for the PCI memory regions (I/O space region is not
+	supported by hardware)
+	Please refer to the standard PCI bus binding document for a more
+	detailed explanation
+- msi-controller: indicates that this is MSI controller node
+- msi-parent:  MSI parent of the root complex itself
+- legacy-interrupt-controller: Interrupt controller device node for Legacy interrupts
+	- interrupt-controller: identifies the node as an interrupt controller
+	- #interrupt-cells: should be set to 1
+	- #address-cells: specifies the number of cells needed to encode an
+		address. The value must be 0.
+
+
+Example:
+++++++++
+
+nwl_pcie: pcie@fd0e0000 {
+	#address-cells = <3>;
+	#size-cells = <2>;
+	compatible = "xlnx,nwl-pcie-2.11";
+	#interrupt-cells = <1>;
+	msi-controller;
+	device_type = "pci";
+	interrupt-parent = <&gic>;
+	interrupts = <0 114 4>, <0 115 4>, <0 116 4>, <0 117 4>, <0 118 4>;
+	interrupt-names = "msi0", "msi1", "intx", "dummy", "misc";
+	interrupt-map-mask = <0x0 0x0 0x0 0x7>;
+	interrupt-map = <0x0 0x0 0x0 0x1 &pcie_intc 0x1>,
+			<0x0 0x0 0x0 0x2 &pcie_intc 0x2>,
+			<0x0 0x0 0x0 0x3 &pcie_intc 0x3>,
+			<0x0 0x0 0x0 0x4 &pcie_intc 0x4>;
+
+	msi-parent = <&nwl_pcie>;
+	reg = <0x0 0xfd0e0000 0x0 0x1000>,
+	      <0x0 0xfd480000 0x0 0x1000>,
+	      <0x0 0xe0000000 0x0 0x1000000>;
+	reg-names = "breg", "pcireg", "cfg";
+	ranges = <0x02000000 0x00000000 0xe1000000 0x00000000 0xe1000000 0 0x0f000000>;
+
+	pcie_intc: legacy-interrupt-controller {
+		interrupt-controller;
+		#address-cells = <0>;
+		#interrupt-cells = <1>;
+	};
+
+};

drivers/pci/host/Kconfig

@@ -16,6 +16,16 @@ config PCI_MVEBU
 	depends on ARCH_MVEBU || ARCH_DOVE
 	depends on OF
 
+config PCIE_XILINX_NWL
+	bool "NWL PCIe Core"
+	depends on ARCH_ZYNQMP
+	select PCI_MSI_IRQ_DOMAIN if PCI_MSI
+	help
+	 Say 'Y' here if you want kernel support for Xilinx
+	 NWL PCIe controller. The controller can act as Root Port
+	 or End Point. The current option selection will only
+	 support root port enabling.
+
 config PCIE_DW
 	bool
 

drivers/pci/host/Makefile

@@ -10,6 +10,7 @@ obj-$(CONFIG_PCI_HOST_GENERIC) += pci-host-generic.o
 obj-$(CONFIG_PCIE_SPEAR13XX) += pcie-spear13xx.o
 obj-$(CONFIG_PCI_KEYSTONE) += pci-keystone-dw.o pci-keystone.o
 obj-$(CONFIG_PCIE_XILINX) += pcie-xilinx.o
+obj-$(CONFIG_PCIE_XILINX_NWL) += pcie-xilinx-nwl.o
 obj-$(CONFIG_PCI_XGENE) += pci-xgene.o
 obj-$(CONFIG_PCI_XGENE_MSI) += pci-xgene-msi.o
 obj-$(CONFIG_PCI_LAYERSCAPE) += pci-layerscape.o