Provide wbwd(4), a driver for the watchdog timer found on various

Winbond Super I/O chips.

With minor efforts it should be possible the extend the driver to support
further chips/revisions available from Winbond.  In the simplest case
only new IDs need to be added, while different chipsets might require
their own function to enter extended function mode, etc.

Sponsored by:	Sandvine Incorporated ULC (in 2011)
Reviewed by:	emaste, brueffer
MFC after:	2 weeks

1 files changed, 117 insertions, 0 deletions

diff --git a/share/man/man4/wbwd.4 b/share/man/man4/wbwd.4
new file mode 100644
index 0000000..2b24fab
--- /dev/null
+++ b/share/man/man4/wbwd.4
@@ -0,0 +1,117 @@
+.\"-
+.\" Copyright (c) 2012 Bjoern A. Zeeb <bz@FreeBSD.org>
+.\" 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 AUTHOR 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 AUTHOR 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.
+.\"
+.\" $FreeBSD$
+.\"
+.Dd March 6, 2012
+.Dt wbwd 4
+.Os
+.Sh NAME
+.Nm wbwd
+.Nd device driver for watchdog timer found on Winbond Super I/O chips
+.Sh SYNOPSIS
+To compile this driver into the kernel, place the following line in your
+kernel configuration file:
+.Bd -ragged -offset indent
+.Cd "device wbwd"
+.Ed
+.Pp
+Alternatively, to load the driver as a module at boot time, place the following
+line in
+.Xr loader.conf 5 :
+.Bd -literal -offset indent
+wbwd_load="YES"
+.Ed
+.Pp
+In
+.Pa /boot/device.hints :
+.Cd hint.wbwd.0.at="isa"
+.Sh DESCRIPTION
+The
+.Nm
+driver provides
+.Xr watchdog 4
+support for the watchdog interrupt timer present on at least the following
+Winbond Super I/O chips:
+.Pp
+.Bl -bullet -compact
+.It
+83627HF/F/HG/G Rev. G
+.It
+83627HF/F/HG/G Rev. J
+.It
+83627HF/F/HG/G Rev. UD-A
+.It
+83627DHG IC ver. 5
+.El
+.Sh SYSCTL VARIABLES
+The
+.Nm
+driver provides the following options as
+.Xr sysctl 8
+variables.
+.Bl -tag -width "xxxxxx"  
+.It Va dev.wbwd.0.timeout_override
+This variable allows to program the timer to a value independent on the one
+provided by the
+.Xr watchdog 4
+framework while still relying on the regular updates from e.g.
+.Xr watchdogd 8 .
+This is particularly useful if your system provides multiple watchdogs and
+you want them to fire in a special sequence to trigger an NMI after a shorter
+period than the reset timeout for example.
+The value set must not be lower than the sleep time of
+.Xr watchdogd 8 .
+A value of 0 disables this feature and the timeout value provided by
+.Xr watchdog 4
+will be used.
+.It Va dev.wbwd.0.debug_verbose
+If set this sysctl will tell the driver to log its current state before and
+after the timer reset on each invocation from
+.Xr watchdog 9
+to the kernel message buffer for debugging.
+.It Va dev.wbwd.0.debug
+This read-only value gives the state of some registers on last update.
+.El
+.Pp
+The
+.Nm
+driver also provides further sysctl options that are hidden by default.
+See the source code for more information.
+.Sh SEE ALSO
+.Xr watchdog 4 ,
+.Xr device.hints 5 ,
+.Xr watchdog 8 ,
+.Xr watchdogd 8 ,
+.Xr watchdog 9
+.Sh HISTORY
+The
+.Nm
+driver first appeared in
+.Fx 10.0 .
+.Sh AUTHORS
+.An -nosplit
+This manual page was written by
+.An Bjoern A. Zeeb Aq bz@FreeBSD.org .