PCICONFIG_READ

Section: Linux Programmer's Manual (2)
Updated: 2016-07-17
Page Index

NAME

pciconfig_read, pciconfig_write, pciconfig_iobase - pci device information handling

SYNOPSIS

#include <pci.h>

int pciconfig_read(unsigned long bus, unsigned long dfn,
          unsigned long off, unsigned long len, void *buf);
int pciconfig_write(unsigned long bus, unsigned long dfn,
          unsigned long off, unsigned long len, void *buf);
int pciconfig_iobase(long which, unsigned long bus,
          unsigned long devfn);

DESCRIPTION

Most of the interaction with PCI devices is already handled by the kernel PCI layer, and thus these calls should not normally need to be accessed from user space.

pciconfig_read(): Reads to buf from device dev at offset off value.
pciconfig_write(): Writes from buf to device dev at offset off value.
pciconfig_iobase(): You pass it a bus/devfn pair and get a physical address for either the memory offset (for things like prep, this is 0xc0000000), the IO base for PIO cycles, or the ISA holes if any.

RETURN VALUE

pciconfig_read(): On success, zero is returned. On error, -1 is returned and errno is set appropriately.
pciconfig_write(): On success, zero is returned. On error, -1 is returned and errno is set appropriately.
pciconfig_iobase(): Returns information on locations of various I/O regions in physical memory according to the which value. Values for which are: IOBASE_BRIDGE_NUMBER, IOBASE_MEMORY, IOBASE_IO, IOBASE_ISA_IO, IOBASE_ISA_MEM.

ERRORS

EINVAL: len value is invalid. This does not apply to pciconfig_iobase().
EIO: I/O error.
ENODEV: For pciconfig_iobase(), "hose" value is NULL. For the other calls, could not find a slot.
ENOSYS: The system has not implemented these calls (CONFIG_PCI not defined).
EOPNOTSUPP: This return value is valid only for pciconfig_iobase(). It is returned if the value for which is invalid.
EPERM: User does not have the CAP_SYS_ADMIN capability. This does not apply to pciconfig_iobase().

CONFORMING TO

These calls are Linux-specific, available since Linux 2.0.26/2.1.11.

COLOPHON

This page is part of release 4.16 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.