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 $
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 ".It Dv PCIOCGETCONF"
79 It allows the user to retrieve information on all
81 devices in the system, or on
83 devices matching patterns supplied by the user.
86 to any value specified in either
92 structure consists of a number of fields:
93 .Bl -tag -width ".Fa match_buf_len"
95 The length, in bytes, of the buffer filled with user-supplied patterns.
97 The number of user-supplied patterns.
99 Pointer to a buffer filled with user-supplied patterns.
107 structure consists of the following elements:
108 .Bl -tag -width ".Fa pd_vendor"
111 domain, bus, slot and function.
117 device driver unit number.
128 The flags describe which of the fields the kernel should match against.
129 A device must match all specified fields in order to be returned.
130 The match flags are enumerated in the
131 .Vt pci_getconf_flags
133 Hopefully the flag values are obvious enough that they do not need to
139 buffer allocated by the user to hold the results of the
143 Number of matches returned by the kernel.
145 Buffer containing matching devices returned by the kernel.
146 The items in this buffer are of type
148 which consists of the following items:
149 .Bl -tag -width ".Fa pc_subvendor"
152 domain, bus, slot and function.
176 device programming interface.
186 The offset is passed in by the user to tell the kernel where it should
187 start traversing the device list.
188 The value passed out by the kernel
189 points to the record immediately after the last one returned.
191 pass the value returned by the kernel in subsequent calls to the
194 If the user does not intend to use the offset, it must be set to zero.
197 configuration generation.
198 This value only needs to be set if the offset is set.
199 The kernel will compare the current generation number of its internal
200 device list to the generation passed in by the user to determine whether
201 its device list has changed since the user last called the
204 If the device list has changed, a status of
205 .Dv PCI_GETCONF_LIST_CHANGED
208 The status tells the user the disposition of his request for a device list.
209 The possible status values are:
211 .It Dv PCI_GETCONF_LAST_DEVICE
212 This means that there are no more devices in the PCI device list after the
216 .It Dv PCI_GETCONF_LIST_CHANGED
217 This status tells the user that the
219 device list has changed since his last call to the
221 ioctl and he must reset the
225 to zero to start over at the beginning of the list.
226 .It Dv PCI_GETCONF_MORE_DEVS
227 This tells the user that his buffer was not large enough to hold all of the
228 remaining devices in the device list that possibly match his criteria.
229 It is possible for this status to be returned, even when none of the remaining
230 devices in the list would match the user's criteria.
231 .It Dv PCI_GETCONF_ERROR
232 This indicates a general error while servicing the user's request.
238 .Fn sizeof "struct pci_match_conf" ,
249 configuration registers specified by the passed-in
254 structure consists of the following fields:
255 .Bl -tag -width ".Fa pi_width"
259 structure which specifies the domain, bus, slot and function the user would
261 If the specific bus is not found,
265 and -1 returned from the ioctl.
269 configuration register the user would like to access.
271 The width, in bytes, of the data the user would like to read.
272 This value may be either 1, 2, or 4.
273 3-byte reads and reads larger than 4 bytes are not supported.
274 If an invalid width is passed,
279 The data returned by the kernel.
284 allows users to write to the
286 specified in the passed-in
291 structure is described above.
292 The limitations on data width described for
293 reading registers, above, also apply to writing
295 configuration registers.
298 .Bl -tag -width /dev/pci -compact
300 Character device for the
309 driver (not the kernel's
311 support code) first appeared in
313 and was written by Stefan Esser and Garrett Wollman.
314 Support for device listing and matching was re-implemented by
315 Kenneth Merry, and first appeared in
318 .An Kenneth Merry Aq Mt ken@FreeBSD.org
320 It is not possible for users to specify an accurate offset into the device
321 list without calling the
323 at least once, since they have no way of knowing the current generation
325 This probably is not a serious problem, though, since
326 users can easily narrow their search by specifying a pattern or patterns
327 for the kernel to match against.