The Peripheral Component Interconnect (PCI) bus is a little endian bus. PCI devices are self-identifying -- that is to say the PCI device provides configuration parameters to the system, which allows the system to identify the device and its driver. The configuration parameters are represented in the form of name-value pairs that can be retrieved using the DDI property interfaces. See ddi_prop_lookup(9F) for details.

The PCI bus properties are derived from PCI configuration space, or supplied by the Fcode PROM, if it exists. Therefore, driver configuration files are not necessary for these devices.

On some occasions, drivers for PCI devices can use driver configuration files to provide driver private properties through the global property mechanism. See driver.conf(4) for further details. Driver configuration files can also be used to augment or override properties for a specific instance of a driver.

All bus drivers of class pci recognize the following properties:

reg

An arbitrary length array where each element of the array consists of a 5-tuple of 32-bit values. Each array element describes a logically contiguous mappable resource on the PCI bus.

The first three values in the 5-tuple describe the PCI address of the mappable resource. The first tuple contains the following information:

Bits 0 - 7	8-bit register number
Bits 8 - 10	3-bit function number
Bits 11 - 15	5-bit device number
Bits 16 - 23	8-bit bus number
Bits 24 - 25	2-bit address space type identifier

The address space type identifier can be interpreted as follows:

0x0	configuration space
0x1	I/O space
0x2	32-bit memory space address
0x3	64-bit memory space address

The bus number is a unique identifying number assigned to each PCI bus within a PCI domain.

The device number is a unique identifying number assigned to each PCI device on a PCI bus. Note that a device number is unique only within the set of device numbers for a particular bus.

Each PCI device can have one to eight logically independent functions, each with its own independent set of configuration registers. Each function on a device is assigned a function number. For a PCI device with only one function, the function number must be 0.

The register number field selects a particular register within the set of configuration registers corresponding to the selected function.

The second and third values in the reg property 5-tuple specify the 64-bit address of the mappable resource within the PCI address domain. The second 32-bit tuple corresponds to the high order four bytes of the 64-bit address. The third 32-bit tuple corresponds to the low order bytes.

The fourth and fifth 32-bit values in the 5-tuple reg property specify the size of the mappable resource. The size is a 64-bit value, where the fourth tuple corresponds to the high order bytes of the 64-bit size and the fifth corresponds to the low order.

The driver can refer to the elements of this array by index, and construct kernel mappings to these addresses using ddi_regs_map_setup(9F). The index into the array is passed as the rnumber argument of ddi_regs_map_setup(9F).

At a high-level interrupt context, you can use the ddi_get* and ddi_put* family of functions to access I/O and memory space. However, access to configuration space is not allowed when running at a high-interrupt level.

interrupts

This property consists of a single-integer element array. Valid interrupt property values are 1, 2, 3, and 4. This value is derived directly from the contents of the device's configuration-interrupt-pin register.

A driver should use an index value of 0 when registering its interrupt handler with ddi_add_intr(9F).

All PCI devices support the reg property. The device number and function number as derived from the reg property are used to construct the address part of the device name under /devices.

Only devices that generate interrupts support an interrupts property.

Occasionally it might be necessary to override or augment the configuration information supplied by a PCI device. This change can be achieved by writing a driver configuration file that describes a prototype device node specification containing the additional properties required.

For the system to merge the prototype node specification into an actual device node, certain conditions must be met.

• First, the name property must be identical. The value of the name property needs to match the binding name of the device. The binding name is the name chosen by the system to bind a driver to a device and is either an alias associated with the driver or the hardware node name of the device.
• Second, the parent property must identify the PCI bus.
• Third, the unit-address property must identify the card. The format of the unit-address property is:

DD[,F]

where DD is the device number and F is the function number. If the function number is 0, only DD is specified.

See attributes(5) for descriptions of the following attributes:

driver.conf(4), attributes(5), ddi_add_intr(9F), ddi_prop_lookup(9F), ddi_regs_map_setup(9F)

Writing Device Drivers

IEEE 1275 PCI Bus Binding