PCI(3)

NAME
pci - library interface for PCI bus access

LIBRARY
libpci

SYNOPSIS
#include <pci.h>
int
pcibus_conf_read(int pcifd, u_int bus, u_int dev, u_int func, u_int reg, pcireg_t *valp);
int
pcibus_conf_write(int pcifd, u_int bus, u_int dev, u_int func, u_int reg, pcireg_t val);
int
pcidev_conf_read(int devfd, u_int reg, pcireg_t *valp);
int
pcidev_conf_write(int devfd, u_int reg, pcireg_t val);
char *
pci_findvendor(pcireg_t id_reg);
void
pci_devinfo(pcireg_t id_reg, pcireg_t class_reg, char *devinfo, size_t len);
void
pci_conf_print(int pcifd, u_int bus, u_int dev, u_int func);

DESCRIPTION
The pci library provides support for accessing the PCI bus by user programs.

These functions are available in the libpci library. Programs should be linked with -lpci.

CONFIGURATION SPACE FUNCTIONS
The following functions are used to access PCI configuration space:

pcibus_conf_read()
    Access the PCI configuration register reg on the device located at bus, dev, func, and place the result in *valp. pcifd must be an open file descriptor to a PCI bus within the target PCI domain.

pcibus_conf_write()
    Write the value specified by val into the PCI configuration register reg on the device located at bus, dev, func. pcifd must be an open file descriptor to a PCI bus within the target PCI domain.

pcidev_conf_read()
    Access the PCI configuration register reg on the device associated with the open file descriptor devfd and place the result in *valp.

pcidev_conf_write()
    Write the value specified by val into the PCI configuration register reg on the device associated with the open file descriptor devfd.

MISCELLANEOUS FUNCTIONS
The following miscellaneous functions are available:

pci_findvendor()
    Return an ASCII description of the PCI vendor in the PCI ID register id_reg.

pci_devinfo()
    Return an ASCII description of the PCI vendor, PCI product, and PCI class specified by the PCI ID register id_reg and PCI class ID register class_reg. The description is placed into the buffer pointed to by devinfo; the size of that buffer is specified in len.

pci_conf_print()
    Print the PCI configuration information for the device located at bus, dev, func. pcifd must be an open file descriptor to a PCI bus within the target PCI domain.

RETURN VALUES
The pcibus_conf_read(), pcibus_conf_write(), pcidev_conf_read(), and pcidev_conf_write() functions return 0 on success and -1 on failure.

The pci_findvendor() function returns NULL if the PCI vendor description cannot be found.

SEE ALSO
pci(4)

HISTORY
The pcibus_conf_read(), pcibus_conf_write(), pcidev_conf_read(), pcidev_conf_write(), pci_findvendor(), pci_devinfo(), and pci_conf_print() functions first appeared in NetBSD 1.6.