pci(9)

NAME

pci, pci_read_config, pci_write_config,

pci_enable_busmaster,
pci_disable_busmaster, pci_enable_io, pci_disable_io,

pci_set_powerstate,
pci_get_powerstate, pci_find_bsf, pci_find_device - PCI bus

interface

SYNOPSIS

#include <sys/bus.h>
#include <dev/pci/pcivar.h>
#include <dev/pci/pcireg.h>
#include <machine/pci_cfgreg.h>
void
pci_write_config(device_t  dev,  int  reg, uint32_t val, int
width);
int
pci_enable_busmaster(device_t dev);
int
pci_disable_busmaster(device_t dev);
int
pci_enable_io(device_t dev, int space);
int
pci_disable_io(device_t dev, int space);
int
pci_set_powerstate(device_t dev, int state);
int
pci_get_powerstate(device_t dev);
uint32_t
pci_read_config(device_t dev, int reg, int width);
device_t
pci_find_bsf(uint8_t bus, uint8_t slot, uint8_t func);
device_t
pci_find_device(uint16_t vendor, uint16_t device);

DESCRIPTION

The pci set of functions are used for managing PCI devices.

The pci_read_config() function is used to read data from the

PCI configuration space of the device dev, at offset reg, with width

specifying the
size of the access.

The pci_write_config() function is used to write the value

val to the PCI
configuration space of the device dev, at offset reg, with

width specifying the size of the access.

The pci_enable_busmaster() function enables PCI bus master

ing for the
device dev, by setting the PCIM_CMD_BUSMASTEREN bit in the

PCIR_COMMAND
register. The pci_disable_busmaster() function clears this

bit.

The pci_enable_io() function enables memory or I/O port ad

dress decoding
for the device dev, by setting the PCIM_CMD_MEMEN or

PCIM_CMD_PORTEN bit
in the PCIR_COMMAND register appropriately. The

pci_disable_io() function clears the appropriate bit. The space argument speci

fies which
resource is affected; this can be either SYS_RES_MEMORY or

SYS_RES_IOPORT
as appropriate.

NOTE: These functions should be used in preference to manu

ally manipulating the configuration space.

The pci_get_powerstate() function returns the current ACPI

power state of
the device dev. If the device does not support power man

agement capabilities, then the default state of PCI_POWERSTATE_D0 is re

turned. The following power states are defined by ACPI:

PCI_POWERSTATE_D0 State in which device is on and

running. It

is receiving full power from the

system and
delivering full functionality to

the user.

PCI_POWERSTATE_D1 Class-specific low-power state

in which

device context may or may not be

lot. Busses
in this state cannot do anything

to the bus,
to force devices to lose con

text.

PCI_POWERSTATE_D2 Class-specific low-power state

in which

device context may or may not be

lost.
Attains greater power savings

than
PCI_POWERSTATE_D1. Busses in

this state can
cause devices to lose some con

text. Devices
must be prepared for the bus to

be in this
state or higher.

PCI_POWERSTATE_D3 State in which the device is off

and not run

ning. Device context is lost,

and power from
the device can be removed.

PCI_POWERSTATE_UNKNOWN State of the device is unknown.

The pci_set_powerstate() function is used to transition the

device dev to
the ACPI power state state. It checks to see if the device

is PCI 2.2
compliant. If so, it checks the capabilities pointer to de

termine which
power states the device supports. If the device does not

have power management capabilities, the default state of PCI_POWERSTATE_D0

is set.

The pci_find_bsf() function looks up the device_t of a PCI

device, given
its bus, slot, and func. The slot number actually refers to

the number
of the device on the bus, which does not necessarily indi

cate its geographic location in terms of a physical slot.

The pci_find_device() function looks up the device_t of a

PCI device,
given its vendor and device IDs. Note that there can be

multiple matches
for this search; this function only returns the first match

ing device.

IMPLEMENTATION NOTES

The pci_addr_t type varies according to the size of the PCI

bus address
space on the target architecture.

SEE ALSO

pci(4), pciconf(8), bus_alloc_resource(9), bus_dma(9),
bus_release_resource(9), bus_setup_intr(9), bus_teardown_in

tr(9),
devclass(9), device(9), driver(9), rman(9)

"NewBus", FreeBSD Developers' Handbook, http://www.FreeBSD.org/doc/en_US.ISO8859-1/books/developers

handbook/.

Shanley and Anderson, PCI System Architecture,

Addison-Wesley, 2nd
Edition, ISBN 0-201-30974-2.

AUTHORS

This manual page was written by Bruce M Simpson <bms@FreeB

SD.org>.

BUGS

The kernel PCI code has a number of references to ``slot

numbers''.
These do not refer to the geographic location of PCI de

vices, but to the
device number assigned by the combination of the PCI IDSEL

mechanism and
the platform firmware. This should be taken note of when

working with
the kernel PCI code.

BSD January 22, 2005

BSD