10012d5309
Previously the loop in PCIIOCGETCONF would terminate as soon as it found enough matches. Now it will continue iterating through the PCI device list and only terminate if it finds another matching device for which it has no room to store a conf structure. This means that PCI_GETCONF_LAST_DEVICE is reliably returned when the number of matching devices is equal to the number of slots in the matches buffer. For example, if a program requests the conf structure for a single PCI function with a specified domain/bus/slot/function it will now get PCI_GETCONF_LAST_DEVICE instead of PCI_GETCONF_MORE_DEVS. While here, simplify the loop conditional a bit more by explicitly breaking out of the loop if copyout() fails and removing a redundant i < pci_numdevs check. Reviewed by: vangyzen, imp MFC after: 1 month Sponsored by: Chelsio Communications Differential Revision: https://reviews.freebsd.org/D7445
343 lines
8.3 KiB
Groff
343 lines
8.3 KiB
Groff
.\"
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.\" Copyright (c) 1999 Kenneth D. Merry.
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. The name of the author may not be used to endorse or promote products
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.\" derived from this software without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd August 9, 2016
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.Dt PCI 4
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.Os
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.Sh NAME
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.Nm pci
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.Nd generic PCI driver
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.Sh SYNOPSIS
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.Cd device pci
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.Sh DESCRIPTION
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The
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.Nm
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driver provides a way for userland programs to read and write
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.Tn PCI
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configuration registers.
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It also provides a way for userland programs to get a list of all
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.Tn PCI
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devices, or all
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.Tn PCI
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devices that match various patterns.
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.Pp
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Since the
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.Nm
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driver provides a write interface for
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.Tn PCI
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configuration registers, system administrators should exercise caution when
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granting access to the
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.Nm
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device.
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If used improperly, this driver can allow userland applications to
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crash a machine or cause data loss.
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.Pp
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The
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.Nm
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driver implements the
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.Tn PCI
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bus in the kernel.
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It enumerates any devices on the
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.Tn PCI
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bus and gives
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.Tn PCI
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client drivers the chance to attach to them.
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It assigns resources to children, when the BIOS does not.
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It takes care of routing interrupts when necessary.
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It reprobes the unattached
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.Tn PCI
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children when
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.Tn PCI
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client drivers are dynamically
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loaded at runtime.
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.Sh KERNEL CONFIGURATION
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The
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.Nm
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device is included in the kernel as described in the SYNOPSIS section.
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The
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.Nm
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driver cannot be built as a
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.Xr kld 4 .
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.Sh IOCTLS
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The following
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.Xr ioctl 2
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calls are supported by the
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.Nm
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driver.
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They are defined in the header file
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.In sys/pciio.h .
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.Bl -tag -width 012345678901234
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.It PCIOCGETCONF
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This
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.Xr ioctl 2
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takes a
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.Va pci_conf_io
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structure.
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It allows the user to retrieve information on all
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.Tn PCI
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devices in the system, or on
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.Tn PCI
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devices matching patterns supplied by the user.
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The call may set
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.Va errno
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to any value specified in either
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.Xr copyin 9
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or
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.Xr copyout 9 .
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The
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.Va pci_conf_io
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structure consists of a number of fields:
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.Bl -tag -width match_buf_len
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.It pat_buf_len
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The length, in bytes, of the buffer filled with user-supplied patterns.
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.It num_patterns
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The number of user-supplied patterns.
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.It patterns
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Pointer to a buffer filled with user-supplied patterns.
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.Va patterns
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is a pointer to
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.Va num_patterns
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.Va pci_match_conf
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structures.
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The
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.Va pci_match_conf
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structure consists of the following elements:
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.Bl -tag -width pd_vendor
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.It pc_sel
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.Tn PCI
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domain, bus, slot and function.
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.It pd_name
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.Tn PCI
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device driver name.
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.It pd_unit
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.Tn PCI
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device driver unit number.
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.It pc_vendor
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.Tn PCI
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vendor ID.
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.It pc_device
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.Tn PCI
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device ID.
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.It pc_class
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.Tn PCI
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device class.
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.It flags
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The flags describe which of the fields the kernel should match against.
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A device must match all specified fields in order to be returned.
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The match flags are enumerated in the
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.Va pci_getconf_flags
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structure.
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Hopefully the flag values are obvious enough that they do not need to
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described in detail.
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.El
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.It match_buf_len
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Length of the
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.Va matches
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buffer allocated by the user to hold the results of the
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.Dv PCIOCGETCONF
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query.
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.It num_matches
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Number of matches returned by the kernel.
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.It matches
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Buffer containing matching devices returned by the kernel.
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The items in this buffer are of type
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.Va pci_conf ,
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which consists of the following items:
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.Bl -tag -width pc_subvendor
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.It pc_sel
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.Tn PCI
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domain, bus, slot and function.
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.It pc_hdr
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.Tn PCI
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header type.
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.It pc_subvendor
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.Tn PCI
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subvendor ID.
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.It pc_subdevice
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.Tn PCI
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subdevice ID.
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.It pc_vendor
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.Tn PCI
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vendor ID.
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.It pc_device
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.Tn PCI
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device ID.
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.It pc_class
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.Tn PCI
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device class.
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.It pc_subclass
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.Tn PCI
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device subclass.
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.It pc_progif
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.Tn PCI
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device programming interface.
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.It pc_revid
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.Tn PCI
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revision ID.
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.It pd_name
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Driver name.
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.It pd_unit
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Driver unit number.
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.El
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.It offset
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The offset is passed in by the user to tell the kernel where it should
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start traversing the device list.
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The value passed out by the kernel
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points to the record immediately after the last one returned.
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The user may
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pass the value returned by the kernel in subsequent calls to the
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.Dv PCIOCGETCONF
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ioctl.
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If the user does not intend to use the offset, it must be set to zero.
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.It generation
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.Tn PCI
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configuration generation.
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This value only needs to be set if the offset is set.
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The kernel will compare the current generation number of its internal
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device list to the generation passed in by the user to determine whether
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its device list has changed since the user last called the
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.Dv PCIOCGETCONF
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ioctl.
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If the device list has changed, a status of
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.Va PCI_GETCONF_LIST_CHANGED
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will be passed back.
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.It status
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The status tells the user the disposition of his request for a device list.
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The possible status values are:
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.Bl -ohang
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.It PCI_GETCONF_LAST_DEVICE
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This means that there are no more devices in the PCI device list matching
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the specified criteria after the
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ones returned in the
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.Va matches
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buffer.
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.It PCI_GETCONF_LIST_CHANGED
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This status tells the user that the
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.Tn PCI
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device list has changed since his last call to the
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.Dv PCIOCGETCONF
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ioctl and he must reset the
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.Va offset
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and
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.Va generation
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to zero to start over at the beginning of the list.
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.It PCI_GETCONF_MORE_DEVS
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This tells the user that his buffer was not large enough to hold all of the
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remaining devices in the device list that match his criteria.
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.It PCI_GETCONF_ERROR
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This indicates a general error while servicing the user's request.
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If the
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.Va pat_buf_len
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is not equal to
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.Va num_patterns
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times
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.Fn sizeof "struct pci_match_conf" ,
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.Va errno
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will be set to
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.Er EINVAL .
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.El
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.El
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.It PCIOCREAD
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This
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.Xr ioctl 2
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reads the
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.Tn PCI
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configuration registers specified by the passed-in
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.Va pci_io
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structure.
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The
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.Va pci_io
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structure consists of the following fields:
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.Bl -tag -width pi_width
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.It pi_sel
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A
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.Va pcisel
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structure which specifies the domain, bus, slot and function the user would
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like to query.
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If the specific bus is not found, errno will be set to ENODEV and -1 returned
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from the ioctl.
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.It pi_reg
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The
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.Tn PCI
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configuration register the user would like to access.
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.It pi_width
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The width, in bytes, of the data the user would like to read.
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This value
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may be either 1, 2, or 4.
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3-byte reads and reads larger than 4 bytes are
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not supported.
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If an invalid width is passed, errno will be set to EINVAL.
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.It pi_data
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The data returned by the kernel.
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.El
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.It PCIOCWRITE
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This
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.Xr ioctl 2
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allows users to write to the
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.Tn PCI
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specified in the passed-in
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.Va pci_io
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structure.
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The
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.Va pci_io
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structure is described above.
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The limitations on data width described for
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reading registers, above, also apply to writing
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.Tn PCI
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configuration registers.
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.El
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.Sh FILES
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.Bl -tag -width /dev/pci -compact
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.It Pa /dev/pci
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Character device for the
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.Nm
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driver.
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.El
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.Sh SEE ALSO
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.Xr pciconf 8
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.Sh HISTORY
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The
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.Nm
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driver (not the kernel's
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.Tn PCI
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support code) first appeared in
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.Fx 2.2 ,
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and was written by Stefan Esser and Garrett Wollman.
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Support for device listing and matching was re-implemented by
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Kenneth Merry, and first appeared in
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.Fx 3.0 .
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.Sh AUTHORS
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.An Kenneth Merry Aq Mt ken@FreeBSD.org
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.Sh BUGS
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It is not possible for users to specify an accurate offset into the device
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list without calling the
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.Dv PCIOCGETCONF
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at least once, since they have no way of knowing the current generation
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number otherwise.
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This probably is not a serious problem, though, since
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users can easily narrow their search by specifying a pattern or patterns
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for the kernel to match against.
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