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 structure consists of a number of fields:
88 .Bl -tag -width ".Fa match_buf_len"
90 The length, in bytes, of the buffer filled with user-supplied patterns.
92 The number of user-supplied patterns.
94 Pointer to a buffer filled with user-supplied patterns.
102 structure consists of the following elements:
103 .Bl -tag -width ".Fa pd_vendor"
106 bus, slot and function.
112 device driver unit number.
123 The flags describe which of the fields the kernel should match against.
124 A device must match all specified fields in order to be returned.
125 The match flags are enumerated in the
126 .Vt pci_getconf_flags
128 Hopefully the flag values are obvious enough that they don't need to
134 buffer allocated by the user to hold the results of the
138 Number of matches returned by the kernel.
140 Buffer containing matching devices returned by the kernel.
141 The items in this buffer are of type
143 which consists of the following items:
144 .Bl -tag -width ".Fa pc_subvendor"
147 bus, slot and function.
171 device programming interface.
181 The offset is passed in by the user to tell the kernel where it should
182 start traversing the device list.
183 The value passed out by the kernel
184 points to the record immediately after the last one returned.
186 pass the value returned by the kernel in subsequent calls to the
189 If the user does not intend to use the offset, it must be set to zero.
192 configuration generation.
193 This value only needs to be set if the offset is set.
194 The kernel will compare the current generation number of its internal
195 device list to the generation passed in by the user to determine whether
196 its device list has changed since the user last called the
199 If the device list has changed, a status of
200 .Dv PCI_GETCONF_LIST_CHANGED
203 The status tells the user the disposition of his request for a device list.
204 The possible status values are:
206 .It Dv PCI_GETCONF_LAST_DEVICE
207 This means that there are no more devices in the PCI device list after the
211 .It Dv PCI_GETCONF_LIST_CHANGED
212 This status tells the user that the
214 device list has changed since his last call to the
216 ioctl and he must reset the
220 to zero to start over at the beginning of the list.
221 .It Dv PCI_GETCONF_MORE_DEVS
222 This tells the user that his buffer was not large enough to hold all of the
223 remaining devices in the device list that possibly match his criteria.
224 It is possible for this status to be returned, even when none of the remaining
225 devices in the list would match the user's criteria.
226 .It Dv PCI_GETCONF_ERROR
227 This indicates a general error while servicing the user's request.
229 specific indication of the problem may or may not be printed in the kernel
230 message buffer (and by implication, the system console).
238 configuration registers specified by the passed-in
243 structure consists of the following fields:
244 .Bl -tag -width ".Fa pi_width"
248 structure which specifies the bus, slot and function the user would like to
253 configuration register the user would like to access.
255 The width, in bytes, of the data the user would like to read.
256 This value may be either 1, 2, or 4.
257 3-byte reads and reads larger than 4 bytes are not supported.
259 The data returned by the kernel.
264 allows users to write to the
266 specified in the passed-in
271 structure is described above.
272 The limitations on data width described for
273 reading registers, above, also apply to writing
275 configuration registers.
278 .Bl -tag -width /dev/pci -compact
280 Character device for the
291 driver (not the kernel's
293 support code) first appeared in
295 and was written by Stefan Esser and Garrett Wollman.
296 Support for device listing and matching was re-implemented by
297 Kenneth Merry, and first appeared in
300 .An Kenneth Merry Aq ken@FreeBSD.org
302 It isn't possible for users to specify an accurate offset into the device
303 list without calling the
305 at least once, since they have no way of knowing the current generation
307 This probably isn't a serious problem, though, since
308 users can easily narrow their search by specifying a pattern or patterns
309 for the kernel to match against.