.\" Contributed by Niki A. Rahimi, LTC Security Development

.\" narahimi@us.ibm.com

.\"

.\" %%%LICENSE_START(FREELY_REDISTRIBUTABLE)

.\" May be freely distributed and modified.

.\" %%%LICENSE_END

.\"

.TH PCICONFIG_READ 2 2016-07-17 "Linux" "Linux Programmer's Manual"

.SH NAME

pciconfig_read, pciconfig_write, pciconfig_iobase \- pci device information handling

.SH SYNOPSIS

.nf

.B #include <pci.h>

.PP

.BI "int pciconfig_read(unsigned long " bus ", unsigned long " dfn ,

.BI "          unsigned long " off ", unsigned long " len ", void *" buf );

.BI "int pciconfig_write(unsigned long " bus ", unsigned long " dfn ,

.BI "          unsigned long " off ", unsigned long " len ", void *" buf );

.BI "int pciconfig_iobase(long " which ", unsigned long " bus ,

.BI "          unsigned long " devfn );

.fi

.SH DESCRIPTION

.PP

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.

.TP

.BR pciconfig_read ()

Reads to

.I buf

from device

.I dev

at offset

.I off

value.

.TP

.BR pciconfig_write ()

Writes from

.I buf

to device

.I dev

at offset

.I off

value.

.TP

.BR 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.

.SH RETURN VALUE

.TP

.BR pciconfig_read ()

On success, zero is returned.

On error, \-1 is returned and

.I errno

is set appropriately.

.TP

.BR pciconfig_write ()

On success, zero is returned.

On error, \-1 is returned and

.I errno

is set appropriately.

.TP

.BR pciconfig_iobase ()

Returns information on locations of various I/O

regions in physical memory according to the

.I which

value.

Values for

.I which

are:

.BR IOBASE_BRIDGE_NUMBER ,

.BR IOBASE_MEMORY ,

.BR IOBASE_IO ,

.BR IOBASE_ISA_IO ,

.BR IOBASE_ISA_MEM .

.SH ERRORS

.TP

.B EINVAL

.I len

value is invalid.

This does not apply to

.BR pciconfig_iobase ().

.TP

.B EIO

I/O error.

.TP

.B ENODEV

For

.BR pciconfig_iobase (),

"hose" value is NULL.

For the other calls, could not find a slot.

.TP

.B ENOSYS

The system has not implemented these calls

.RB ( CONFIG_PCI

not defined).

.TP

.B EOPNOTSUPP

This return value is valid only for

.BR pciconfig_iobase ().

It is returned if the value for

.I which

is invalid.

.TP

.B EPERM

User does not have the

.B CAP_SYS_ADMIN

capability.

This does not apply to

.BR pciconfig_iobase ().

.SH CONFORMING TO

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

.SH SEE ALSO

.BR capabilities (7)

.SH COLOPHON

This page is part of release 4.15 of the Linux

.I 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/.