1 .\" $NetBSD: physio.9,v 1.2 1996/11/11 00:05:12 lukem Exp $
3 .\" Copyright (c) 1996 The NetBSD Foundation, Inc.
4 .\" All rights reserved.
6 .\" This code is derived from software contributed to The NetBSD Foundation
7 .\" by Paul Kranenburg.
9 .\" Redistribution and use in source and binary forms, with or without
10 .\" modification, are permitted provided that the following conditions
12 .\" 1. Redistributions of source code must retain the above copyright
13 .\" notice, this list of conditions and the following disclaimer.
14 .\" 2. Redistributions in binary form must reproduce the above copyright
15 .\" notice, this list of conditions and the following disclaimer in the
16 .\" documentation and/or other materials provided with the distribution.
17 .\" 3. All advertising materials mentioning features or use of this software
18 .\" must display the following acknowledgement:
19 .\" This product includes software developed by the NetBSD
20 .\" Foundation, Inc. and its contributors.
21 .\" 4. Neither the name of The NetBSD Foundation nor the names of its
22 .\" contributors may be used to endorse or promote products derived
23 .\" from this software without specific prior written permission.
25 .\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
26 .\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
27 .\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
28 .\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE
29 .\" LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
30 .\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
31 .\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
32 .\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
33 .\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
34 .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
35 .\" POSSIBILITY OF SUCH DAMAGE.
37 .\" $FreeBSD: src/share/man/man9/physio.9,v 1.6.2.4 2001/12/17 11:30:18 ru Exp $
38 .\" $DragonFly: src/share/man/man9/physio.9,v 1.2 2003/06/17 04:37:01 dillon Exp $
45 .Nd initiate I/O on raw devices
51 .Fn physio "dev_t dev" "struct uio *uio" "int ioflag"
55 is a helper function typically called from character device read and write
56 routines to start I/O on a user process buffer.
60 routine one or more times to complete the transfer described by
62 The maximum amount of data to transfer with each call to
69 normally describes user space addresses,
71 needs to lock the process into memory. This is done by setting the
75 always awaits the completion of the entire requested transfer before
76 returning, unless an error condition is detected earlier.
82 for the duration of the entire transfer.
84 A break-down of the arguments follows:
85 .Bl -tag -width indent
87 The device strategy routine to call for each chunk of data to initiate
90 The buffer to use with the strategy routine.
91 The buffer flags will have
95 set when passed to the strategy routine.
98 a buffer is allocated from a system pool.
100 The device number identifying the device to interact with.
102 Direction of transfer; the only valid settings are
107 A device specific routine called to determine the maximum transfer size
108 that the device's strategy routine can handle.
110 The description of the entire transfer as requested by the user process.
111 Currently, the results of passing a
115 set to anything other than
124 is returned if the address range described by
126 is not accessible by the requesting process.
128 will return any error resulting from calls to the device strategy routine,
134 Note that the actual transfer size may be less than requested by
136 if the device signals an