344 lines
8.4 KiB
Groff
344 lines
8.4 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 January 3, 2008
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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 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 possibly match his criteria.
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It is possible for this status to be returned, even when none of the remaining
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devices in the list would match the user's 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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