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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 mastering 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 address 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 specifies 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 manually
     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 management
     capabilities, then the default state of PCI_POWERSTATE_D0 is returned.
     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 context.

     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
                             context.  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 running.
                             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 determine 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 indicate 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 matching 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_intr(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@FreeBSD.org〉.

BUGS

     The kernel PCI code has a number of references to “slot numbers”.  These
     do not refer to the geographic location of PCI devices, 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.