2 .\" Copyright (c) 1999 Kenneth D. Merry.
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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 $
33 .Nd generic PCI driver
39 driver provides a way for userland programs to read and write
41 configuration registers.
42 It also provides a way for userland programs to get a list of all
46 devices that match various patterns.
50 driver provides a write interface for
52 configuration registers, system administrators should exercise caution when
53 granting access to the
56 If used improperly, this driver can allow userland applications to
57 crash a machine or cause data loss.
58 .Sh KERNEL CONFIGURATION
59 It is only necessary to specify one
61 controller in the kernel.
64 busses are handled automatically as they are encountered.
68 calls are supported by the
71 They are defined in the header file
73 .Bl -tag -width ".It Dv PCIOCGETCONF"
80 It allows the user to retrieve information on all
82 devices in the system, or on
84 devices matching patterns supplied by the user.
87 to any value specified in either
93 structure consists of a number of fields:
94 .Bl -tag -width ".Fa match_buf_len"
96 The length, in bytes, of the buffer filled with user-supplied patterns.
98 The number of user-supplied patterns.
100 Pointer to a buffer filled with user-supplied patterns.
108 structure consists of the following elements:
109 .Bl -tag -width ".Fa pd_vendor"
112 domain, bus, slot and function.
118 device driver unit number.
129 The flags describe which of the fields the kernel should match against.
130 A device must match all specified fields in order to be returned.
131 The match flags are enumerated in the
132 .Vt pci_getconf_flags
134 Hopefully the flag values are obvious enough that they do not need to
140 buffer allocated by the user to hold the results of the
144 Number of matches returned by the kernel.
146 Buffer containing matching devices returned by the kernel.
147 The items in this buffer are of type
149 which consists of the following items:
150 .Bl -tag -width ".Fa pc_subvendor"
153 domain, bus, slot and function.
177 device programming interface.
187 The offset is passed in by the user to tell the kernel where it should
188 start traversing the device list.
189 The value passed out by the kernel
190 points to the record immediately after the last one returned.
192 pass the value returned by the kernel in subsequent calls to the
195 If the user does not intend to use the offset, it must be set to zero.
198 configuration generation.
199 This value only needs to be set if the offset is set.
200 The kernel will compare the current generation number of its internal
201 device list to the generation passed in by the user to determine whether
202 its device list has changed since the user last called the
205 If the device list has changed, a status of
206 .Dv PCI_GETCONF_LIST_CHANGED
209 The status tells the user the disposition of his request for a device list.
210 The possible status values are:
212 .It Dv PCI_GETCONF_LAST_DEVICE
213 This means that there are no more devices in the PCI device list after the
217 .It Dv PCI_GETCONF_LIST_CHANGED
218 This status tells the user that the
220 device list has changed since his last call to the
222 ioctl and he must reset the
226 to zero to start over at the beginning of the list.
227 .It Dv PCI_GETCONF_MORE_DEVS
228 This tells the user that his buffer was not large enough to hold all of the
229 remaining devices in the device list that possibly match his criteria.
230 It is possible for this status to be returned, even when none of the remaining
231 devices in the list would match the user's criteria.
232 .It Dv PCI_GETCONF_ERROR
233 This indicates a general error while servicing the user's request.
239 .Fn sizeof "struct pci_match_conf" ,
250 configuration registers specified by the passed-in
255 structure consists of the following fields:
256 .Bl -tag -width ".Fa pi_width"
260 structure which specifies the domain, bus, slot and function the user would
262 If the specific bus is not found,
266 and -1 returned from the ioctl.
270 configuration register the user would like to access.
272 The width, in bytes, of the data the user would like to read.
273 This value may be either 1, 2, or 4.
274 3-byte reads and reads larger than 4 bytes are not supported.
275 If an invalid width is passed,
280 The data returned by the kernel.
285 allows users to write to the
287 specified in the passed-in
292 structure is described above.
293 The limitations on data width described for
294 reading registers, above, also apply to writing
296 configuration registers.
299 .Bl -tag -width /dev/pci -compact
301 Character device for the
310 driver (not the kernel's
312 support code) first appeared in
314 and was written by Stefan Esser and Garrett Wollman.
315 Support for device listing and matching was re-implemented by
316 Kenneth Merry, and first appeared in
319 .An Kenneth Merry Aq ken@FreeBSD.org
321 It is not possible for users to specify an accurate offset into the device
322 list without calling the
324 at least once, since they have no way of knowing the current generation
326 This probably is not a serious problem, though, since
327 users can easily narrow their search by specifying a pattern or patterns
328 for the kernel to match against.