PCI: thunder: Add PCIe host driver for ThunderX processors

The root complexes used to access off-chip PCIe devices (called PEM units
in the hardware manuals) on some Cavium ThunderX processors require quirky
access methods for the config space of the PCIe bridge.

Add a driver to provide these config space accessor functions.  Use the
pci-host-common code to configure the PCI machinery.

Signed-off-by: David Daney <david.daney@cavium.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>

Documentation/devicetree/bindings/pci/pci-thunder-pem.txt

@@ -0,0 +1,43 @@
+* ThunderX PEM PCIe host controller
+
+Firmware-initialized PCI host controller found on some Cavium
+ThunderX processors.
+
+The properties and their meanings are identical to those described in
+host-generic-pci.txt except as listed below.
+
+Properties of the host controller node that differ from
+host-generic-pci.txt:
+
+- compatible     : Must be "cavium,pci-host-thunder-pem"
+
+- reg            : Two entries: First the configuration space for down
+                   stream devices base address and size, as accessed
+                   from the parent bus. Second, the register bank of
+                   the PEM device PCIe bridge.
+
+Example:
+
+    pci@87e0,c2000000 {
+	compatible = "cavium,pci-host-thunder-pem";
+	device_type = "pci";
+	msi-parent = <&its>;
+	msi-map = <0 &its 0x10000 0x10000>;
+	bus-range = <0x8f 0xc7>;
+	#size-cells = <2>;
+	#address-cells = <3>;
+
+	reg = <0x8880 0x8f000000 0x0 0x39000000>,  /* Configuration space */
+	      <0x87e0 0xc2000000 0x0 0x00010000>; /* PEM space */
+	ranges = <0x01000000 0x00 0x00020000 0x88b0 0x00020000 0x00 0x00010000>, /* I/O */
+		 <0x03000000 0x00 0x10000000 0x8890 0x10000000 0x0f 0xf0000000>, /* mem64 */
+		 <0x43000000 0x10 0x00000000 0x88a0 0x00000000 0x10 0x00000000>, /* mem64-pref */
+		 <0x03000000 0x87e0 0xc2f00000 0x87e0 0xc2000000 0x00 0x00100000>; /* mem64 PEM BAR4 */
+
+	#interrupt-cells = <1>;
+	interrupt-map-mask = <0 0 0 7>;
+	interrupt-map = <0 0 0 1 &gic0 0 0 0 24 4>, /* INTA */
+			<0 0 0 2 &gic0 0 0 0 25 4>, /* INTB */
+			<0 0 0 3 &gic0 0 0 0 26 4>, /* INTC */
+			<0 0 0 4 &gic0 0 0 0 27 4>; /* INTD */
+    };

MAINTAINERS

@@ -8419,6 +8419,14 @@ L:     linux-arm-msm@vger.kernel.org
 S:     Maintained
 F:     drivers/pci/host/*qcom*
 
+PCIE DRIVER FOR CAVIUM THUNDERX
+M:	David Daney <david.daney@cavium.com>
+L:	linux-pci@vger.kernel.org
+L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
+S:	Supported
+F:	Documentation/devicetree/bindings/pci/pci-thunder-*
+F:	drivers/pci/host/pci-thunder-*
+
 PCMCIA SUBSYSTEM
 P:	Linux PCMCIA Team
 L:	linux-pcmcia@lists.infradead.org

drivers/pci/host/Kconfig

@@ -195,4 +195,11 @@ config PCIE_QCOM
 	  PCIe controller uses the Designware core plus Qualcomm-specific
 	  hardware wrappers.
 
+config PCI_HOST_THUNDER_PEM
+	bool "Cavium Thunder PCIe controller to off-chip devices"
+	depends on OF && ARM64
+	select PCI_HOST_COMMON
+	help
+	  Say Y here if you want PCIe support for CN88XX Cavium Thunder SoCs.
+
 endmenu

drivers/pci/host/Makefile

@@ -23,3 +23,4 @@ obj-$(CONFIG_PCIE_ALTERA) += pcie-altera.o
 obj-$(CONFIG_PCIE_ALTERA_MSI) += pcie-altera-msi.o
 obj-$(CONFIG_PCI_HISI) += pcie-hisi.o
 obj-$(CONFIG_PCIE_QCOM) += pcie-qcom.o
+obj-$(CONFIG_PCI_HOST_THUNDER_PEM) += pci-thunder-pem.o