Add watchdog API documentation, from Michael Knudsen, with tweaks. ok grange jmc

2 files changed, 67 insertions, 2 deletions

diff --git a/share/man/man9/Makefile b/share/man/man9/Makefile
index 8c79c117705..68a37e10acc 100644
--- a/share/man/man9/Makefile
+++ b/share/man/man9/Makefile
@@ -1,4 +1,4 @@
-#	$OpenBSD: Makefile,v 1.86 2004/11/30 14:47:59 pedro Exp $
+#	$OpenBSD: Makefile,v 1.87 2004/12/17 17:32:02 jaredy Exp $
 #	$NetBSD: Makefile,v 1.4 1996/01/09 03:23:01 thorpej Exp $
 
 #	Makefile for section 9 (kernel function and variable) manual pages.
@@ -22,7 +22,7 @@ MAN=	altq.9 audio.9 autoconf.9 boot.9 buffercache.9 bus_dma.9 bus_space.9 \
 	vaccess.9 vclean.9 vcount.9 vdevgone.9 vfinddev.9 vflush.9 \
 	vflushbuf.9 vget.9 vgone.9 vhold.9 vinvalbuf.9 vput.9 vref.9 \
 	vrele.9 vnode.9 VOP_LOOKUP.9 vn_lock.9 vrecycle.9 vwaitforio.9 \
-	vwakeup.9
+	vwakeup.9 wdog_register.9
 
 MLINKS+=autoconf.9 config_init.9 autoconf.9 config_search.9 \
 	autoconf.9 config_rootsearch.9 autoconf.9 config_found_sm.9 \
diff --git a/share/man/man9/wdog_register.9 b/share/man/man9/wdog_register.9
new file mode 100644
index 00000000000..4f06b5f6079
--- /dev/null
+++ b/share/man/man9/wdog_register.9
@@ -0,0 +1,65 @@
+.\"	$OpenBSD: wdog_register.9,v 1.1 2004/12/17 17:32:02 jaredy Exp $
+.\"
+.\" Copyright (c) 2004 Michael Knudsen <mk@molioner.dk>
+.\" 
+.\" Permission to use, copy, modify, and distribute this software for any
+.\" purpose with or without fee is hereby granted, provided that the above
+.\" copyright notice and this permission notice appear in all copies.
+.\" 
+.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+.\"
+.Dd December 17, 2004
+.Dt WDOG_REGISTER 9
+.Os
+.Sh NAME
+.Nm wdog_register
+.Nd kernel watchdog interface
+.Sh SYNOPSIS
+.In sys/systm.h
+.Ft void
+.Fn wdog_register "void *cb_arg" "int (*cb)(void *cb_arg, int period)"
+.Sh DESCRIPTION
+The kernel watchdog interface is used by hardware watchdog drivers and
+should be used for all future drivers.
+.Pp
+.Fn wdog_register
+is called by the hardware driver after configuring the hardware watchdog
+device.
+The
+.Fa cb_arg
+argument is a pointer to the hardware device control structure.
+The
+.Fa cb
+argument is a pointer to a function supplied by the driver which sets
+the timeout in the hardware device.
+.Pp
+The
+.Fa cb_arg
+parameter given to
+.Fa cb
+is a pointer to the device control structure.
+The
+.Fa period
+parameter supplies the desired timeout value in seconds.
+A
+.Fa period
+value of zero disables the watchdog.
+Setting the timeout to a nonzero value after disabling the watchdog
+will update the timeout value and enable the watchdog.
+.Sh CODE REFERENCES
+The framework is implemented in the file
+.Pa sys/kern/kern_watchdog.c .
+.Sh SEE ALSO
+.Xr watchdog 4 ,
+.Xr timeout 9
+.Sh HISTORY
+The watchdog timer framework was written by
+.An Markus Friedl Aq markus@openbsd.org
+and first appeared in
+.Ox 3.3 .