* Mediatek/Ralink RT3883 PCI controller
1) Main node
Required properties:
- compatible: must be "ralink,rt3883-pci"
- reg: specifies the physical base address of the controller and
the length of the memory mapped region.
- #address-cells: specifies the number of cells needed to encode an
address. The value must be 1.
- #size-cells: specifies the number of cells used to represent the size
of an address. The value must be 1.
- ranges: specifies the translation between child address space and parent
address space
Optional properties:
- status: indicates the operational status of the device.
Value must be either "disabled" or "okay".
2) Child nodes
The main node must have two child nodes which describes the built-in
interrupt controller and the PCI host bridge.
a) Interrupt controller:
Required properties:
- interrupt-controller: identifies the node as an interrupt controller
- #address-cells: specifies the number of cells needed to encode an
address. The value must be 0. As such, 'interrupt-map' nodes do not
have to specify a parent unit address.
- #interrupt-cells: specifies the number of cells needed to encode an
interrupt source. The value must be 1.
- interrupt-parent: the phandle for the interrupt controller that
services interrupts for this device.
- interrupts: specifies the interrupt source of the parent interrupt
controller. The format of the interrupt specifier depends on the
parent interrupt controller.
b) PCI host bridge:
Required properties:
- #address-cells: specifies the number of cells needed to encode an
address. The value must be 0.
- #size-cells: specifies the number of cells used to represent the size
of an address. The value must be 2.
- #interrupt-cells: specifies the number of cells needed to encode an
interrupt source. The value must be 1.
- device_type: must be "pci"
- bus-range: PCI bus numbers covered
- ranges: specifies the ranges for the PCI memory and I/O regions
- interrupt-map-mask,
- interrupt-map: standard PCI properties to define the mapping of the
PCI interface to interrupt numbers.
The PCI host bridge node migh have additional sub-nodes representing
the onboard PCI devices/PCI slots. Each such sub-node must have the
following mandatory properties:
- reg: used only for interrupt mapping, so only the first four bytes
are used to refer to the correct bus number and device number.
- device_type: must be "pci"
If a given sub-node represents a PCI bridge it must have following
mandatory properties as well:
- #address-cells: must be set to <3>
- #size-cells: must set to <2>
- #interrupt-cells: must be set to <1>
- interrupt-map-mask,
- interrupt-map: standard PCI properties to define the mapping of the
PCI interface to interrupt numbers.
Besides the required properties the sub-nodes may have these optional
properties:
- status: indicates the operational status of the sub-node.
Value must be either "disabled" or "okay".
3) Example:
a) SoC specific dtsi file:
pci@10140000 {
compatible = "ralink,rt3883-pci";
reg = <0x10140000 0x20000>;
#address-cells = <1>;
#size-cells = <1>;
ranges; /* direct mapping */
status = "disabled";
pciintc: interrupt-controller {
interrupt-controller;
#address-cells = <0>;
#interrupt-cells = <1>;
interrupt-parent = <&cpuintc>;
interrupts = <4>;
};
host-bridge {
#address-cells = <3>;
#size-cells = <2>;
#interrupt-cells = <1>;
device_type = "pci";
bus-range = <0 255>;
ranges = <
0x02000000 0 0x00000000 0x20000000 0 0x10000000 /* pci memory */
0x01000000 0 0x00000000 0x10160000 0 0x00010000 /* io space */
>;
interrupt-map-mask = <0xf800 0 0 7>;
interrupt-map = <
/* IDSEL 17 */
0x8800 0 0 1 &pciintc 18
0x8800 0 0 2 &pciintc 18
0x8800 0 0 3 &pciintc 18
0x8800 0 0 4 &pciintc 18
/* IDSEL 18 */
0x9000 0 0 1 &pciintc 19
0x9000 0 0 2 &pciintc 19
0x9000 0 0 3 &pciintc 19
0x9000 0 0 4 &pciintc 19
>;
pci-bridge@1 {
reg = <0x0800 0 0 0 0>;
device_type = "pci";
#interrupt-cells = <1>;
#address-cells = <3>;
#size-cells = <2>;
interrupt-map-mask = <0x0 0 0 0>;
interrupt-map = <0x0 0 0 0 &pciintc 20>;
status = "disabled";
};
pci-slot@17 {
reg = <0x8800 0 0 0 0>;
device_type = "pci";
status = "disabled";
};
pci-slot@18 {
reg = <0x9000 0 0 0 0>;
device_type = "pci";
status = "disabled";
};
};
};
b) Board specific dts file:
pci@10140000 {
status = "okay";
host-bridge {
pci-bridge@1 {
status = "okay";
};
};
};