2 .\" Copyright (c) 1999 Kenneth D. Merry.
3 .\" All rights reserved.
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27 .Dd September 30, 2007
32 .Nd generic PCI driver
38 driver provides a way for userland programs to read and write
40 configuration registers.
41 It also provides a way for userland programs to get a list of all
45 devices that match various patterns.
49 driver provides a write interface for
51 configuration registers, system administrators should exercise caution when
52 granting access to the
55 If used improperly, this driver can allow userland applications to
56 crash a machine or cause data loss.
57 .Sh KERNEL CONFIGURATION
58 It is only necessary to specify one
60 controller in the kernel.
63 busses are handled automatically as they are encountered.
67 calls are supported by the
70 They are defined in the header file
72 .Bl -tag -width 012345678901234
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 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 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 .Va 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 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 .Va 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 PCI_GETCONF_LAST_DEVICE
213 This means that there are no more devices in the PCI device list after the
217 .It 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 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 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 pi_width
260 structure which specifies the domain, bus, slot and function the user would
262 If the specific bus is not found, errno will be set to ENODEV and -1 returned
267 configuration register the user would like to access.
269 The width, in bytes, of the data the user would like to read.
271 may be either 1, 2, or 4.
272 3-byte reads and reads larger than 4 bytes are
274 If an invalid width is passed, errno will be set to EINVAL.
276 The data returned by the kernel.
281 allows users to write to the
283 specified in the passed-in
288 structure is described above.
289 The limitations on data width described for
290 reading registers, above, also apply to writing
292 configuration registers.
295 .Bl -tag -width /dev/pci -compact
297 Character device for the
306 driver (not the kernel's
308 support code) first appeared in
310 and was written by Stefan Esser and Garrett Wollman.
311 Support for device listing and matching was re-implemented by
312 Kenneth Merry, and first appeared in
315 .An Kenneth Merry Aq ken@FreeBSD.org
317 It is not possible for users to specify an accurate offset into the device
318 list without calling the
320 at least once, since they have no way of knowing the current generation
322 This probably is not a serious problem, though, since
323 users can easily narrow their search by specifying a pattern or patterns
324 for the kernel to match against.