Support for Generic PCI Host Controller

index db3c5414223e..860bea828ac4 100644
@@ -314,6 +314,7 @@ config ARCH_MULTIPLATFORM
 	select CLKSRC_OF
 	select COMMON_CLK
 	select GENERIC_CLOCKEVENTS
+	select MIGHT_HAVE_PCI
 	select MULTI_IRQ_HANDLER
 	select SPARSE_IRQ
 	select USE_OF

index 49c914cd9c7a..764c129b5eee 100644
@@ -55,7 +55,6 @@ config ARCH_BCM_5301X
 	select GENERIC_CLOCKEVENTS
 	select ARM_GLOBAL_TIMER
 	select CLKSRC_ARM_GLOBAL_TIMER_SCHED_CLOCK
-	select MIGHT_HAVE_PCI
 	help
 	  Support for Broadcom BCM470X and BCM5301X SoCs with ARM CPU cores.
 

index dce8decd5d46..66838f42037f 100644
@@ -1,7 +1,6 @@
 config ARCH_CNS3XXX
 	bool "Cavium Networks CNS3XXX family" if ARCH_MULTI_V6
 	select ARM_GIC
-	select MIGHT_HAVE_PCI
 	select PCI_DOMAINS if PCI
 	help
 	  Support for Cavium Networks CNS3XXX platform.

index 5740296dc429..50bb546b893a 100644
@@ -796,7 +796,6 @@ config SOC_IMX6Q
 	select ARM_ERRATA_764369 if SMP
 	select HAVE_ARM_SCU if SMP
 	select HAVE_ARM_TWD if SMP
-	select MIGHT_HAVE_PCI
 	select PCI_DOMAINS if PCI
 	select PINCTRL_IMX6Q
 	select SOC_IMX6

index 3f73eecbcfb0..120301ebd324 100644
@@ -9,7 +9,6 @@ config ARCH_MVEBU
 	select MVEBU_MBUS
 	select ZONE_DMA if ARM_LPAE
 	select ARCH_REQUIRE_GPIOLIB
-	select MIGHT_HAVE_PCI
 	select PCI_QUIRKS if PCI
 	select OF_ADDRESS_PCI
 

index 0f92ba8e7884..905003898913 100644
@@ -8,7 +8,6 @@ config ARCH_SHMOBILE_MULTI
 	select HAVE_ARM_SCU if SMP
 	select HAVE_ARM_TWD if SMP
 	select ARM_GIC
-	select MIGHT_HAVE_PCI
 	select ARCH_DMA_ADDR_T_64BIT if ARM_LPAE
 	select NO_IOPORT_MAP
 	select PINCTRL

index 55b305d51669..e16999e5b735 100644
@@ -7,7 +7,6 @@ config ARCH_TEGRA
 	select CLKSRC_MMIO
 	select HAVE_ARM_SCU if SMP
 	select HAVE_ARM_TWD if SMP
-	select MIGHT_HAVE_PCI
 	select PINCTRL
 	select ARCH_HAS_RESET_CONTROLLER
 	select RESET_CONTROLLER

new file mode 100644
index 000000000000..f0b0436807b4
@@ -0,0 +1,100 @@
+* Generic PCI host controller
+
+Firmware-initialised PCI host controllers and PCI emulations, such as the
+virtio-pci implementations found in kvmtool and other para-virtualised
+systems, do not require driver support for complexities such as regulator
+and clock management. In fact, the controller may not even require the
+configuration of a control interface by the operating system, instead
+presenting a set of fixed windows describing a subset of IO, Memory and
+Configuration Spaces.
+
+Such a controller can be described purely in terms of the standardized device
+tree bindings communicated in pci.txt:
+
+
+Properties of the host controller node:
+
+- compatible     : Must be "pci-host-cam-generic" or "pci-host-ecam-generic"
+                   depending on the layout of configuration space (CAM vs
+                   ECAM respectively).
+
+- device_type    : Must be "pci".
+
+- ranges         : As described in IEEE Std 1275-1994, but must provide
+                   at least a definition of non-prefetchable memory. One
+                   or both of prefetchable Memory and IO Space may also
+                   be provided.
+
+- bus-range      : Optional property (also described in IEEE Std 1275-1994)
+                   to indicate the range of bus numbers for this controller.
+                   If absent, defaults to <0 255> (i.e. all buses).
+
+- #address-cells : Must be 3.
+
+- #size-cells    : Must be 2.
+
+- reg            : The Configuration Space base address and size, as accessed
+                   from the parent bus.
+
+
+Properties of the /chosen node:
+
+- linux,pci-probe-only
+                 : Optional property which takes a single-cell argument.
+                   If '0', then Linux will assign devices in its usual manner,
+                   otherwise it will not try to assign devices and instead use
+                   them as they are configured already.
+
+Configuration Space is assumed to be memory-mapped (as opposed to being
+accessed via an ioport) and laid out with a direct correspondence to the
+geography of a PCI bus address by concatenating the various components to
+form an offset.
+
+For CAM, this 24-bit offset is:
+
+        cfg_offset(bus, device, function, register) =
+                   bus << 16 | device << 11 | function << 8 | register
+
+Whilst ECAM extends this by 4 bits to accomodate 4k of function space:
+
+        cfg_offset(bus, device, function, register) =
+                   bus << 20 | device << 15 | function << 12 | register
+
+Interrupt mapping is exactly as described in `Open Firmware Recommended
+Practice: Interrupt Mapping' and requires the following properties:
+
+- #interrupt-cells   : Must be 1
+
+- interrupt-map      : <see aforementioned specification>
+
+- interrupt-map-mask : <see aforementioned specification>
+
+
+Example:
+
+pci {
+    compatible = "pci-host-cam-generic"
+    device_type = "pci";
+    #address-cells = <3>;
+    #size-cells = <2>;
+    bus-range = <0x0 0x1>;
+
+    // CPU_PHYSICAL(2)  SIZE(2)
+    reg = <0x0 0x40000000  0x0 0x1000000>;
+
+    // BUS_ADDRESS(3)  CPU_PHYSICAL(2)  SIZE(2)
+    ranges = <0x01000000 0x0 0x01000000  0x0 0x01000000  0x0 0x00010000>,
+             <0x02000000 0x0 0x41000000  0x0 0x41000000  0x0 0x3f000000>;
+
+
+    #interrupt-cells = <0x1>;
+
+    // PCI_DEVICE(3)  INT#(1)  CONTROLLER(PHANDLE)  CONTROLLER_DATA(3)
+    interrupt-map = <  0x0 0x0 0x0  0x1  &gic  0x0 0x4 0x1
+                     0x800 0x0 0x0  0x1  &gic  0x0 0x5 0x1
+                    0x1000 0x0 0x0  0x1  &gic  0x0 0x6 0x1
+                    0x1800 0x0 0x0  0x1  &gic  0x0 0x7 0x1>;
+
+    // PCI_DEVICE(3)  INT#(1)
+    interrupt-map-mask = <0xf800 0x0 0x0  0x7>;
+}

index a6f67ec8882f..32d446effbb3 100644
@@ -33,4 +33,11 @@ config PCI_RCAR_GEN2
 	  There are 3 internal PCI controllers available with a single
 	  built-in EHCI/OHCI host controller present on each one.
 
+config PCI_HOST_GENERIC
+	bool "Generic PCI host controller"
+	depends on ARM && OF
+	help
+	  Say Y here if you want to support a simple generic PCI host
+	  controller, such as the one emulated by kvmtool.
+
 endmenu

index 13fb3333aa05..bd1bf1ab4ac8 100644
@@ -4,3 +4,4 @@ obj-$(CONFIG_PCI_IMX6) += pci-imx6.o
 obj-$(CONFIG_PCI_MVEBU) += pci-mvebu.o
 obj-$(CONFIG_PCI_TEGRA) += pci-tegra.o
 obj-$(CONFIG_PCI_RCAR_GEN2) += pci-rcar-gen2.o
+obj-$(CONFIG_PCI_HOST_GENERIC) += pci-host-generic.o

index 106626442124..424874c9a692 100644
@@ -6751,6 +6751,14 @@ L:	linux-pci at vger.kernel.org
 S:	Maintained
 F:	drivers/pci/host/*designware*
 
+PCI DRIVER FOR GENERIC OF HOSTS
+M:	Will Deacon <[email protected]>
+L:	linux-pci at vger.kernel.org
+L:	linux-arm-kernel at lists.infradead.org (moderated for non-subscribers)
+S:	Maintained
+F:	Documentation/devicetree/bindings/pci/host-generic-pci.txt
+F:	drivers/pci/host/pci-host-generic.c
+
 PCMCIA SUBSYSTEM
 P:	Linux PCMCIA Team
 L:	linux-pcmcia at lists.infradead.org