2 .\" Copyright (c) 1999 Kenneth D. Merry.
3 .\" All rights reserved.
5 .\" Redistribution and use in source and binary forms, with or without
6 .\" modification, are permitted provided that the following conditions
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.
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
32 .Nd generic PCI bus driver
34 To compile the PCI bus driver into the kernel,
35 place the following line in your
36 kernel configuration file:
37 .Bd -ragged -offset indent
41 To compile in support for Single Root I/O Virtualization
43 .Bd -ragged -offset indent
47 To compile in support for native PCI-express HotPlug:
48 .Bd -ragged -offset indent
54 driver provides support for
56 devices in the kernel and limited access to
64 character device that can be used by userland programs to read and write
66 configuration registers.
67 Programs can also use this device to get a list of all
71 devices that match various patterns.
75 driver provides a write interface for
77 configuration registers, system administrators should exercise caution when
78 granting access to the
81 If used improperly, this driver can allow userland applications to
82 crash a machine or cause data loss.
89 It enumerates any devices on the
93 client drivers the chance to attach to them.
94 It assigns resources to children, when the BIOS does not.
95 It takes care of routing interrupts when necessary.
96 It reprobes the unattached
100 client drivers are dynamically
104 driver also includes support for PCI-PCI bridges,
105 various platform-specific Host-PCI bridges,
106 and basic support for
112 calls are supported by the
115 They are defined in the header file
117 .Bl -tag -width 012345678901234
124 It allows the user to retrieve information on all
126 devices in the system, or on
128 devices matching patterns supplied by the user.
131 to any value specified in either
137 structure consists of a number of fields:
138 .Bl -tag -width match_buf_len
140 The length, in bytes, of the buffer filled with user-supplied patterns.
142 The number of user-supplied patterns.
144 Pointer to a buffer filled with user-supplied patterns.
152 structure consists of the following elements:
153 .Bl -tag -width pd_vendor
156 domain, bus, slot and function.
162 device driver unit number.
173 The flags describe which of the fields the kernel should match against.
174 A device must match all specified fields in order to be returned.
175 The match flags are enumerated in the
176 .Va pci_getconf_flags
178 Hopefully the flag values are obvious enough that they do not need to
184 buffer allocated by the user to hold the results of the
188 Number of matches returned by the kernel.
190 Buffer containing matching devices returned by the kernel.
191 The items in this buffer are of type
193 which consists of the following items:
194 .Bl -tag -width pc_subvendor
197 domain, bus, slot and function.
221 device programming interface.
231 The offset is passed in by the user to tell the kernel where it should
232 start traversing the device list.
233 The value passed out by the kernel
234 points to the record immediately after the last one returned.
236 pass the value returned by the kernel in subsequent calls to the
239 If the user does not intend to use the offset, it must be set to zero.
242 configuration generation.
243 This value only needs to be set if the offset is set.
244 The kernel will compare the current generation number of its internal
245 device list to the generation passed in by the user to determine whether
246 its device list has changed since the user last called the
249 If the device list has changed, a status of
250 .Va PCI_GETCONF_LIST_CHANGED
253 The status tells the user the disposition of his request for a device list.
254 The possible status values are:
256 .It PCI_GETCONF_LAST_DEVICE
257 This means that there are no more devices in the PCI device list after the
261 .It PCI_GETCONF_LIST_CHANGED
262 This status tells the user that the
264 device list has changed since his last call to the
266 ioctl and he must reset the
270 to zero to start over at the beginning of the list.
271 .It PCI_GETCONF_MORE_DEVS
272 This tells the user that his buffer was not large enough to hold all of the
273 remaining devices in the device list that possibly match his criteria.
274 It is possible for this status to be returned, even when none of the remaining
275 devices in the list would match the user's criteria.
276 .It PCI_GETCONF_ERROR
277 This indicates a general error while servicing the user's request.
283 .Fn sizeof "struct pci_match_conf" ,
294 configuration registers specified by the passed-in
299 structure consists of the following fields:
300 .Bl -tag -width pi_width
304 structure which specifies the domain, bus, slot and function the user would
306 If the specific bus is not found, errno will be set to ENODEV and -1 returned
311 configuration register the user would like to access.
313 The width, in bytes, of the data the user would like to read.
315 may be either 1, 2, or 4.
316 3-byte reads and reads larger than 4 bytes are
318 If an invalid width is passed, errno will be set to EINVAL.
320 The data returned by the kernel.
325 allows users to write to the
327 specified in the passed-in
332 structure is described above.
333 The limitations on data width described for
334 reading registers, above, also apply to writing
336 configuration registers.
339 Tunables can be set at the
341 prompt before booting the kernel, or stored in
343 The current value of these tunables can be examined at runtime via
345 nodes of the same name.
346 Unless otherwise specified,
347 each of these tunables is a boolean that can be enabled by setting the
348 tunable to a non-zero value.
349 .Bl -tag -width indent
350 .It Va hw.pci.clear_bars Pq Defaults to 0
351 Ignore any firmware-assigned memory and I/O port resources.
354 bus driver to allocate resource ranges for memory and I/O port resources
356 .It Va hw.pci.clear_buses Pq Defaults to 0
357 Ignore any firmware-assigned bus number registers in PCI-PCI bridges.
360 bus driver and PCI-PCI bridge driver to allocate bus numbers for secondary
361 buses behind PCI-PCI bridges.
362 .It Va hw.pci.clear_pcib Pq Defaults to 0
363 Ignore any firmware-assigned memory and I/O port resource windows in PCI-PCI
365 This forces the PCI-PCI bridge driver to allocate memory and I/O port resources
366 for resource windows from scratch.
368 By default the PCI-PCI bridge driver will allocate windows that
369 contain the firmware-assigned resources devices behind the bridge.
370 In addition, the PCI-PCI bridge driver will suballocate from existing window
371 regions when possible to satisfy a resource request.
374 .Va hw.pci.clear_bars
376 .Va hw.pci.clear_pcib
377 must be enabled to fully ignore firmware-supplied resource assignments.
378 .It Va hw.pci.default_vgapci_unit Pq Defaults to -1
382 VGA adapter encountered by the system is assumed to be the boot display device.
383 This tunable can be set to choose a specific VGA adapter by specifying the
384 unit number of the associated
387 .It Va hw.pci.do_power_nodriver Pq Defaults to 0
388 Place devices into a low power state
390 when a suitable device driver is not found.
391 Can be set to one of the following values:
392 .Bl -tag -width indent
396 devices without a device driver.
398 Powers down most devices without a device driver.
399 PCI devices with the display, memory, and base peripheral device classes
400 are not powered down.
402 Similar to a setting of 2 except that storage controllers are also not
405 All devices are left fully powered.
410 device must support power management to be powered down.
411 Placing a device into a low power state may not reduce power consumption.
412 .It Va hw.pci.do_power_resume Pq Defaults to 1
415 devices into the fully powered state when resuming either the system or an
417 Setting this to zero is discouraged as the system will not attempt to power
418 up non-powered PCI devices after a suspend.
419 .It Va hw.pci.do_power_suspend Pq Defaults to 1
422 devices into a low power state when suspending either the system or individual
424 Normally the D3 state is used as the low power state,
425 but firmware may override the desired power state during a system suspend.
426 .It Va hw.pci.enable_ari Pq Defaults to 1
427 Enable support for PCI-express Alternative RID Interpretation.
428 This is often used in conjunction with SR-IOV.
429 .It Va hw.pci.enable_io_modes Pq Defaults to 1
430 Enable memory or I/O port decoding in a PCI device's command register if it has
431 firmware-assigned memory or I/O port resources.
434 in some systems does not enable memory or I/O port decoding for some devices
435 even when it has assigned resources to the device.
436 This enables decoding for such resources during bus probe.
437 .It Va hw.pci.enable_msi Pq Defaults to 1
438 Enable support for Message Signalled Interrupts
440 MSI interrupts can be disabled by setting this tunable to 0.
441 .It Va hw.pci.enable_msix Pq Defaults to 1
442 Enable support for extended Message Signalled Interrupts
444 MSI-X interrupts can be disabled by setting this tunable to 0.
445 .It Va hw.pci.enable_pcie_hp Pq Defaults to 1
446 Enable support for native PCI-express HotPlug.
447 .It Va hw.pci.honor_msi_blacklist Pq Defaults to 1
448 MSI and MSI-X interrupts are disabled for certain chipsets known to have
449 broken MSI and MSI-X implementations when this tunable is set.
450 It can be set to zero to permit use of MSI and MSI-X interrupts if the
451 chipset match is a false positive.
452 .It Va hw.pci.iov_max_config Pq Defaults to 1MB
453 The maximum amount of memory permitted for the configuration parameters
454 used when creating Virtual Functions via SR-IOV.
455 This tunable can also be changed at runtime via
457 .It Va hw.pci.realloc_bars Pq Defaults to 0
458 Attempt to allocate a new resource range during the initial device scan
459 for any memory or I/O port resources with firmware-assigned ranges that
460 conflict with another active resource.
461 .It Va hw.pci.usb_early_takeover Pq Defaults to 1 on Tn amd64 and Tn i386
462 Disable legacy device emulation of USB devices during the initial device
464 Set this tunable to zero to use USB devices via legacy emulation when
465 using a custom kernel without USB controller drivers.
466 .It Va hw.pci<D>.<B>.<S>.INT<P>.irq
467 These tunables can be used to override the interrupt routing for legacy
469 Unlike other tunables in this list,
470 these do not have corresponding sysctl nodes.
471 The tunable name includes the address of the PCI device as well as the
472 pin of the desired INTx IRQ to override:
473 .Bl -tag -width indent
477 of the PCI device in decimal.
479 The bus address of the PCI device in decimal.
481 The slot of the PCI device in decimal.
483 The interrupt pin of the PCI slot to override.
492 The value of the tunable is the raw IRQ value to use for the INTx interrupt
493 pin identified by the tunable name.
494 Mapping of IRQ values to platform interrupt sources is machine dependent.
497 .Bl -tag -width /dev/pci -compact
499 Character device for the
508 driver (not the kernel's
510 support code) first appeared in
512 and was written by Stefan Esser and Garrett Wollman.
513 Support for device listing and matching was re-implemented by
514 Kenneth Merry, and first appeared in
517 .An Kenneth Merry Aq Mt ken@FreeBSD.org
519 It is not possible for users to specify an accurate offset into the device
520 list without calling the
522 at least once, since they have no way of knowing the current generation
524 This probably is not a serious problem, though, since
525 users can easily narrow their search by specifying a pattern or patterns
526 for the kernel to match against.