projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| ce292991 WD |
1 | * Generic PCI host controller |
| 2 | ||
| 3 | Firmware-initialised PCI host controllers and PCI emulations, such as the | |
| 4 | virtio-pci implementations found in kvmtool and other para-virtualised | |
| 5 | systems, do not require driver support for complexities such as regulator | |
| 6 | and clock management. In fact, the controller may not even require the | |
| 7 | configuration of a control interface by the operating system, instead | |
| 8 | presenting a set of fixed windows describing a subset of IO, Memory and | |
| 9 | Configuration Spaces. | |
| 10 | ||
| 11 | Such a controller can be described purely in terms of the standardized device | |
| 12 | tree bindings communicated in pci.txt: | |
| 13 | ||
| 14 | ||
| 15 | Properties of the host controller node: | |
| 16 | ||
| 17 | - compatible : Must be "pci-host-cam-generic" or "pci-host-ecam-generic" | |
| 18 | depending on the layout of configuration space (CAM vs | |
| 19 | ECAM respectively). | |
| 20 | ||
| 21 | - device_type : Must be "pci". | |
| 22 | ||
| 23 | - ranges : As described in IEEE Std 1275-1994, but must provide | |
| 24 | at least a definition of non-prefetchable memory. One | |
| 25 | or both of prefetchable Memory and IO Space may also | |
| 26 | be provided. | |
| 27 | ||
| 28 | - bus-range : Optional property (also described in IEEE Std 1275-1994) | |
| 29 | to indicate the range of bus numbers for this controller. | |
| 30 | If absent, defaults to <0 255> (i.e. all buses). | |
| 31 | ||
| 32 | - #address-cells : Must be 3. | |
| 33 | ||
| 34 | - #size-cells : Must be 2. | |
| 35 | ||
| 36 | - reg : The Configuration Space base address and size, as accessed | |
| f6225c3a DD |
37 | from the parent bus. The base address corresponds to |
| 38 | the first bus in the "bus-range" property. If no | |
| 39 | "bus-range" is specified, this will be bus 0 (the default). | |
| ce292991 WD |
40 | |
| 41 | Properties of the /chosen node: | |
| 42 | ||
| 43 | - linux,pci-probe-only | |
| 44 | : Optional property which takes a single-cell argument. | |
| 45 | If '0', then Linux will assign devices in its usual manner, | |
| 46 | otherwise it will not try to assign devices and instead use | |
| 47 | them as they are configured already. | |
| 48 | ||
| 49 | Configuration Space is assumed to be memory-mapped (as opposed to being | |
| 50 | accessed via an ioport) and laid out with a direct correspondence to the | |
| 51 | geography of a PCI bus address by concatenating the various components to | |
| 52 | form an offset. | |
| 53 | ||
| 54 | For CAM, this 24-bit offset is: | |
| 55 | ||
| 56 | cfg_offset(bus, device, function, register) = | |
| 57 | bus << 16 | device << 11 | function << 8 | register | |
| 58 | ||
| 24488c39 | 59 | Whilst ECAM extends this by 4 bits to accommodate 4k of function space: |
| ce292991 WD |
60 | |
| 61 | cfg_offset(bus, device, function, register) = | |
| 62 | bus << 20 | device << 15 | function << 12 | register | |
| 63 | ||
| 64 | Interrupt mapping is exactly as described in `Open Firmware Recommended | |
| 65 | Practice: Interrupt Mapping' and requires the following properties: | |
| 66 | ||
| 67 | - #interrupt-cells : Must be 1 | |
| 68 | ||
| 69 | - interrupt-map : <see aforementioned specification> | |
| 70 | ||
| 71 | - interrupt-map-mask : <see aforementioned specification> | |
| 72 | ||
| 73 | ||
| 74 | Example: | |
| 75 | ||
| 76 | pci { | |
| 77 | compatible = "pci-host-cam-generic" | |
| 78 | device_type = "pci"; | |
| 79 | #address-cells = <3>; | |
| 80 | #size-cells = <2>; | |
| 81 | bus-range = <0x0 0x1>; | |
| 82 | ||
| 83 | // CPU_PHYSICAL(2) SIZE(2) | |
| 84 | reg = <0x0 0x40000000 0x0 0x1000000>; | |
| 85 | ||
| 86 | // BUS_ADDRESS(3) CPU_PHYSICAL(2) SIZE(2) | |
| 87 | ranges = <0x01000000 0x0 0x01000000 0x0 0x01000000 0x0 0x00010000>, | |
| 88 | <0x02000000 0x0 0x41000000 0x0 0x41000000 0x0 0x3f000000>; | |
| 89 | ||
| 90 | ||
| 91 | #interrupt-cells = <0x1>; | |
| 92 | ||
| 93 | // PCI_DEVICE(3) INT#(1) CONTROLLER(PHANDLE) CONTROLLER_DATA(3) | |
| 94 | interrupt-map = < 0x0 0x0 0x0 0x1 &gic 0x0 0x4 0x1 | |
| 95 | 0x800 0x0 0x0 0x1 &gic 0x0 0x5 0x1 | |
| 96 | 0x1000 0x0 0x0 0x1 &gic 0x0 0x6 0x1 | |
| 97 | 0x1800 0x0 0x0 0x1 &gic 0x0 0x7 0x1>; | |
| 98 | ||
| 99 | // PCI_DEVICE(3) INT#(1) | |
| 100 | interrupt-map-mask = <0xf800 0x0 0x0 0x7>; | |
| 101 | } |