1.\" 2.\" Copyright (c) 1999 Kenneth D. Merry. 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. The name of the author may not be used to endorse or promote products 11.\" derived from this software without specific prior written permission. 12.\" 13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" 25.\" $FreeBSD: src/share/man/man4/pci.4,v 1.3.2.5 2001/08/17 13:08:39 ru Exp $ 26.\" $DragonFly: src/share/man/man4/pci.4,v 1.5 2008/11/13 21:46:03 swildner Exp $ 27.\" 28.Dd July 5, 2009 29.Dt PCI 4 30.Os 31.Sh NAME 32.Nm pci 33.Nd generic PCI driver 34.Sh SYNOPSIS 35.Cd device pci 36.Sh DESCRIPTION 37The 38.Nm 39driver provides a way for userland programs to read and write 40.Tn PCI 41configuration registers. 42It also provides a way for userland programs to get a list of all 43.Tn PCI 44devices, or all 45.Tn PCI 46devices that match various patterns. 47.Pp 48Since the 49.Nm 50driver provides a write interface for 51.Tn PCI 52configuration registers, system administrators should exercise caution when 53granting access to the 54.Nm 55device. 56If used improperly, this driver can allow userland applications to 57crash a machine or cause data loss. 58.Sh KERNEL CONFIGURATION 59It is only necessary to specify one 60.Nm 61controller in the kernel. 62Additional 63.Tn PCI 64busses are handled automatically as they are encountered. 65.Sh IOCTLS 66The following 67.Xr ioctl 2 68calls are supported by the 69.Nm 70driver. 71They are defined in the header file 72.In sys/pciio.h . 73.Bl -tag -width ".It Dv PCIOCGETCONF" 74.It Dv PCIOCGETCONF 75This 76.Xr ioctl 2 77takes a 78.Va pci_conf_io 79structure. 80It allows the user to retrieve information on all 81.Tn PCI 82devices in the system, or on 83.Tn PCI 84devices matching patterns supplied by the user. 85The call may set 86.Va errno 87to any value specified in either 88.Xr copyin 9 89or 90.Xr copyout 9 . 91The 92.Va pci_conf_io 93structure consists of a number of fields: 94.Bl -tag -width ".Fa match_buf_len" 95.It Fa pat_buf_len 96The length, in bytes, of the buffer filled with user-supplied patterns. 97.It Fa num_patterns 98The number of user-supplied patterns. 99.It Fa patterns 100Pointer to a buffer filled with user-supplied patterns. 101.Fa patterns 102is a pointer to 103.Fa num_patterns 104.Vt pci_match_conf 105structures. 106The 107.Vt pci_match_conf 108structure consists of the following elements: 109.Bl -tag -width ".Fa pd_vendor" 110.It Fa pc_sel 111.Tn PCI 112domain, bus, slot and function. 113.It Fa pd_name 114.Tn PCI 115device driver name. 116.It Fa pd_unit 117.Tn PCI 118device driver unit number. 119.It Fa pc_vendor 120.Tn PCI 121vendor ID. 122.It Fa pc_device 123.Tn PCI 124device ID. 125.It Fa pc_class 126.Tn PCI 127device class. 128.It Fa flags 129The flags describe which of the fields the kernel should match against. 130A device must match all specified fields in order to be returned. 131The match flags are enumerated in the 132.Vt pci_getconf_flags 133structure. 134Hopefully the flag values are obvious enough that they do not need to 135described in detail. 136.El 137.It Fa match_buf_len 138Length of the 139.Fa matches 140buffer allocated by the user to hold the results of the 141.Dv PCIOCGETCONF 142query. 143.It Fa num_matches 144Number of matches returned by the kernel. 145.It Fa matches 146Buffer containing matching devices returned by the kernel. 147The items in this buffer are of type 148.Vt pci_conf , 149which consists of the following items: 150.Bl -tag -width ".Fa pc_subvendor" 151.It Fa pc_sel 152.Tn PCI 153domain, bus, slot and function. 154.It Fa pc_hdr 155.Tn PCI 156header type. 157.It Fa pc_subvendor 158.Tn PCI 159subvendor ID. 160.It Fa pc_subdevice 161.Tn PCI 162subdevice ID. 163.It Fa pc_vendor 164.Tn PCI 165vendor ID. 166.It Fa pc_device 167.Tn PCI 168device ID. 169.It Fa pc_class 170.Tn PCI 171device class. 172.It Fa pc_subclass 173.Tn PCI 174device subclass. 175.It Fa pc_progif 176.Tn PCI 177device programming interface. 178.It Fa pc_revid 179.Tn PCI 180revision ID. 181.It Fa pd_name 182Driver name. 183.It Fa pd_unit 184Driver unit number. 185.El 186.It Fa offset 187The offset is passed in by the user to tell the kernel where it should 188start traversing the device list. 189The value passed out by the kernel 190points to the record immediately after the last one returned. 191The user may 192pass the value returned by the kernel in subsequent calls to the 193.Dv PCIOCGETCONF 194ioctl. 195If the user does not intend to use the offset, it must be set to zero. 196.It Fa generation 197.Tn PCI 198configuration generation. 199This value only needs to be set if the offset is set. 200The kernel will compare the current generation number of its internal 201device list to the generation passed in by the user to determine whether 202its device list has changed since the user last called the 203.Dv PCIOCGETCONF 204ioctl. 205If the device list has changed, a status of 206.Dv PCI_GETCONF_LIST_CHANGED 207will be passed back. 208.It Fa status 209The status tells the user the disposition of his request for a device list. 210The possible status values are: 211.Bl -ohang 212.It Dv PCI_GETCONF_LAST_DEVICE 213This means that there are no more devices in the PCI device list after the 214ones returned in the 215.Fa matches 216buffer. 217.It Dv PCI_GETCONF_LIST_CHANGED 218This status tells the user that the 219.Tn PCI 220device list has changed since his last call to the 221.Dv PCIOCGETCONF 222ioctl and he must reset the 223.Fa offset 224and 225.Fa generation 226to zero to start over at the beginning of the list. 227.It Dv PCI_GETCONF_MORE_DEVS 228This tells the user that his buffer was not large enough to hold all of the 229remaining devices in the device list that possibly match his criteria. 230It is possible for this status to be returned, even when none of the remaining 231devices in the list would match the user's criteria. 232.It Dv PCI_GETCONF_ERROR 233This indicates a general error while servicing the user's request. 234If the 235.Fa pat_buf_len 236is not equal to 237.Fa num_patterns 238times 239.Fn sizeof "struct pci_match_conf" , 240.Va errno 241will be set to 242.Er EINVAL . 243.El 244.El 245.It Dv PCIOCREAD 246This 247.Xr ioctl 2 248reads the 249.Tn PCI 250configuration registers specified by the passed-in 251.Vt pci_io 252structure. 253The 254.Vt pci_io 255structure consists of the following fields: 256.Bl -tag -width ".Fa pi_width" 257.It Fa pi_sel 258A 259.Vt pcisel 260structure which specifies the domain, bus, slot and function the user would 261like to query. 262If the specific bus is not found, 263.Va errno 264will be set to 265.Er ENODEV 266and -1 returned from the ioctl. 267.It Fa pi_reg 268The 269.Tn PCI 270configuration register the user would like to access. 271.It Fa pi_width 272The width, in bytes, of the data the user would like to read. 273This value may be either 1, 2, or 4. 2743-byte reads and reads larger than 4 bytes are not supported. 275If an invalid width is passed, 276.Va errno 277will be set to 278.Er EINVAL . 279.It Fa pi_data 280The data returned by the kernel. 281.El 282.It Dv PCIOCWRITE 283This 284.Xr ioctl 2 285allows users to write to the 286.Tn PCI 287specified in the passed-in 288.Vt pci_io 289structure. 290The 291.Vt pci_io 292structure is described above. 293The limitations on data width described for 294reading registers, above, also apply to writing 295.Tn PCI 296configuration registers. 297.El 298.Sh FILES 299.Bl -tag -width /dev/pci -compact 300.It Pa /dev/pci 301Character device for the 302.Nm 303driver. 304.El 305.Sh SEE ALSO 306.Xr pciconf 8 307.Sh HISTORY 308The 309.Nm 310driver (not the kernel's 311.Tn PCI 312support code) first appeared in 313.Fx 2.2 , 314and was written by Stefan Esser and Garrett Wollman. 315Support for device listing and matching was re-implemented by 316Kenneth Merry, and first appeared in 317.Fx 3.0 . 318.Sh AUTHORS 319.An Kenneth Merry Aq ken@FreeBSD.org 320.Sh BUGS 321It is not possible for users to specify an accurate offset into the device 322list without calling the 323.Dv PCIOCGETCONF 324at least once, since they have no way of knowing the current generation 325number otherwise. 326This probably is not a serious problem, though, since 327users can easily narrow their search by specifying a pattern or patterns 328for the kernel to match against. 329