PCI(9)                 FreeBSD Kernel Developer's Manual                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 - kernel interface to
     PCI bus

SYNOPSIS
     #include <sys/bus.h>
     #include <pci/pcivar.h>
     #include <pci/pcireg.h>
     #include <machine/pci_cfgreg.h>

     u_int32_t
     pci_read_config(device_t dev, int reg, int width);

     void
     pci_write_config(device_t dev, int reg, u_int32_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);

     device_t
     pci_find_bsf(u_int8_t, u_int8_t, u_int8_t);

     device_t
     pci_find_device(u_int16_t, u_int16_t);

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 configu-
     ration 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 specify-
     ing 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 state 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 manipulat-
     ing 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 capabil-
     ities, then the default state of PCI_POWERSTATE_D0 is returned.  The fol-
     lowing 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 deliver-
                             ing full functionality to the user.

     PCI_POWERSTATE_D1       Class-specific low-power state in which device
                             context may or may not be lot.  Buses in this
                             state cannot do anything to the bus, to force
                             devices to loose 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.  Buses in
                             this state can cause devices to loose 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 running.
                             Device context is lost, and power from the device
                             can be removed.

     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 man-
     agement 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 function.

     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 is defined according to the size of the PCI bus
     address space on the target system.

SEE ALSO
     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 man page was written by Bruce M Simpson <bms@spc.org>.

BUGS
     This manual page does not yet document PAE and how it affects memory-
     space mapping of PCI devices.

FreeBSD 4.8                      May 21, 2003                      FreeBSD 4.8