Date: Sat, 7 Jul 2018 20:43:01 +0000 (UTC) From: Ian Lepore <ian@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r336076 - head/share/man/man4/man4.arm Message-ID: <201807072043.w67Kh1kE056224@repo.freebsd.org>
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Author: ian Date: Sat Jul 7 20:43:01 2018 New Revision: 336076 URL: https://svnweb.freebsd.org/changeset/base/336076 Log: Add a manpage for the imx5/6 watchdog driver. Added: head/share/man/man4/man4.arm/imx_wdog.4 (contents, props changed) Modified: head/share/man/man4/man4.arm/Makefile Modified: head/share/man/man4/man4.arm/Makefile ============================================================================== --- head/share/man/man4/man4.arm/Makefile Sat Jul 7 19:27:49 2018 (r336075) +++ head/share/man/man4/man4.arm/Makefile Sat Jul 7 20:43:01 2018 (r336076) @@ -4,11 +4,13 @@ PACKAGE=runtime-manuals MAN= cgem.4 \ devcfg.4 \ + imx_wdog.4 \ mge.4 \ npe.4 \ ti_adc.4 MLINKS= cgem.4 if_cgem.4 +MLINKS+= imx_wdog.4 imxwdt.4 MLINKS+= mge.4 if_mge.4 MLINKS+=npe.4 if_npe.4 Added: head/share/man/man4/man4.arm/imx_wdog.4 ============================================================================== --- /dev/null 00:00:00 1970 (empty, because file is newly added) +++ head/share/man/man4/man4.arm/imx_wdog.4 Sat Jul 7 20:43:01 2018 (r336076) @@ -0,0 +1,112 @@ +.\" +.\" Copyright (c) 2018 Ian Lepore <ian@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 ``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 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 July 7, 2018 +.Dt IMX_WDOG 4 +.Os +.Sh NAME +.Nm imx_wdog +.Nd device driver for the NXP i.MX5 and i.MX6 watchdog timer +.Sh SYNOPSIS +To compile this driver into the kernel, +place the following line in your +kernel configuration file: +.Bd -ragged -offset indent +.Cd "device imxwdt" +.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 +imx_wdog_load="YES" +.Ed +.Sh DESCRIPTION +The +.Nm +driver provides +.Xr watchdog 4 +support for the watchdog timer present on NXP i.MX5 and i.MX6 processors. +The i.MX watchdog hardware supports programmable timeouts ranging from +0.5 to 128 seconds, in half-second increments. +Once activated, the watchdog hardware cannot be deactivated, but the +timeout period can be changed to any valid non-zero value. +.Pp +At power-on, a special 16-second +.Sq power-down timer +mode is automatically enabled by the hardware. +It will assert the external WDOG_B signal, which may be connected to +external hardware that causes the system to reset or power-down. +The power-down timer is often reset by the boot loader (typically U-Boot). +If the power-down timer is still active at the time when the normal +watchdog is first enabled, the +.Nm +driver automatically disables it. +.Pp +The +.Nm +driver supports the FDT +.Va fsl,external-reset +property by enabling the assertion of the WDOG_B external timeout signal +when the property is present. +When running this way, the need to reset the system due to watchdog +timeout is signaled by driving the WDOG_B line low; some external +entity is expected to assert the chip's POR pin in response. +The +.Nm +driver attempts to backstop this external reset by scheduling an +interrupt to occur as well. +The interrupt handler waits 1 second for the external reset to occur, +then it triggers a normal software reset. +Note that the WDOG_B signal can be configured to use a variety of +pins on the chip. +For the +.Va fsl,external-reset +property to be effective, the signal must be connected to an appropriate +pin by the system's FDT pinctrl data. +.Pp +The +.Nm +driver supports the FDT +.Va timeout-secs +property by enabling the watchdog as soon as the driver attaches, +using the given timeout value. +This extends watchdog protection to much of the system startup process, +but it still requires that +.Xr watchdogd 4 +be configured to service the watchdog. +.Sh SEE ALSO +.Xr fdt 4 , +.Xr watchdog 4 , +.Xr watchdog 8 , +.Xr watchdogd 8 , +.Xr watchdog 9 +.Sh HISTORY +The +.Nm +driver first appeared in +.Fx 10.0 .
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