.\" $NetBSD: deviter.9,v 1.3 2010/12/02 12:54:13 wiz Exp $ .\" .\" Copyright (c) 2009 David Young .\" All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" .\" THIS SOFTWARE IS PROVIDED BY David Young ``AS IS'' AND ANY EXPRESS .\" OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED .\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL David Young BE LIABLE FOR ANY .\" DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE .\" GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS .\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER .\" IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR .\" OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN .\" IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. .\" .\" NetBSD: pmf.9,v 1.12 2009/10/21 16:06:59 snj Exp .\" .\" Copyright (c) 2007 Jared D. McNeill .\" All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" .\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS .\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED .\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR .\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS .\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR .\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF .\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS .\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN .\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE .\" POSSIBILITY OF SUCH DAMAGE. .\" .Dd November 4, 2009 .Dt DEVITER 9 .Os .Sh NAME .Nm deviter , .Nm deviter_first , .Nm deviter_init , .Nm deviter_next , .Nm deviter_release .Nd machine-independent device iteration API .Sh SYNOPSIS .In sys/device.h .Ft void .Fn deviter_init "deviter_t *di" "deviter_flags_t flags" .Ft device_t .Fn deviter_first "deviter_t *di" "deviter_flags_t flags" .Ft device_t .Fn deviter_next "deviter_t *di" .Ft void .Fn deviter_release "deviter_t *di" .Sh DESCRIPTION The machine-independent .Nm API lets interrupt handlers running at any priority level and kernel threads iterate over the devices attached to the kernel. Using .Nm , it is safe for an interrupt handler or a thread to iterate over devices attached to the kernel while another thread attaches or detaches the devices. .Sh DATA TYPES Kernel subsystems using .Nm may make use of the following data types: .Bl -tag -width compact .It Fa deviter_flags_t The kernel can iterate over devices for different purposes and in different orders. The following flags affect device iteration: .Bl -item -compact -offset indent .It .Dv DEVITER_F_RW .It .Dv DEVITER_F_SHUTDOWN .It .Dv DEVITER_F_LEAVES_FIRST .It .Dv DEVITER_F_ROOT_FIRST .El .It Fa deviter_t This is a device iteration .Dq cursor or .Dq iterator . It holds iteration state such as the next device to visit. .El .Sh FUNCTIONS .Bl -tag -width compact .It Fn deviter_init "di" "flags" Initialize the device iterator, .Fa di . Set bits in .Fa flags to affect the order of iteration. Set .Dv DEVITER_F_LEAVES_FIRST to visit each device only after visiting its children (visit the leaves of the device tree, first). Set .Dv DEVITER_F_ROOT_FIRST to visit each device before visiting its children (visit the root of the device tree, first). If you set neither .Dv DEVITER_F_LEAVES_FIRST nor .Dv DEVITER_F_ROOT_FIRST , .Nm returns devices in an arbitrary order. .Pp Set .Dv DEVITER_F_RW if your purpose for iterating over devices is to modify the device tree by attaching or detaching devices. Set .Dv DEVITER_F_SHUTDOWN if your purpose for iterating over devices is to detach all of the devices during system shutdown. .Dv DEVITER_F_SHUTDOWN implies .Dv DEVITER_F_RW . .It Fn deviter_next "di" Advance the iterator .Fa di to the next device. .Fn deviter_next returns the current device or .Dv NULL if there are no more devices. .Fn deviter_next is undefined if .Fa di has not been initialized using .Fn deviter_init or .Fn deviter_first . .It Fn deviter_first "di" "flags" Initialize the iterator .Fa di with .Fa flags . Return the first device according to the ordering indicated by .Fa flags and advance .Fa di to the second device, or return .Dv NULL if there are no devices. This is equivalent to calling .Fn deviter_init "di" "flags" and then .Fn deviter_next "di" . .It Fn deviter_release "di" Release all resources held by the iterator .Fa di . Every iterator that is initialized with .Fn deviter_first or .Fn deviter_init MUST be released. .El .Sh CODE REFERENCES Device iteration is implemented within the files .Pa sys/sys/device.h and .Pa sys/kern/subr_autoconf.c . .Sh SEE ALSO .Xr autoconf 9 , .Xr driver 9 .Sh HISTORY .Nm appeared in .Nx 5.0 . .Sh AUTHORS .An David Young Aq dyoung@NetBSD.org