mail archive of the barebox mailing list
 help / color / mirror / Atom feed
From: Ahmad Fatoum <>
Cc: Ahmad Fatoum <>,
Subject: [PATCH master 2/2] Documentation: user: watchdog: sync with current state
Date: Mon, 26 Apr 2021 13:34:08 +0200	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

Since most of the documentation was written, the watchdog framework
has gained three more device parameters. Document them.

Signed-off-by: Ahmad Fatoum <>
 Documentation/user/watchdog.rst | 36 +++++++++++++++++++++++++++++----
 1 file changed, 32 insertions(+), 4 deletions(-)

diff --git a/Documentation/user/watchdog.rst b/Documentation/user/watchdog.rst
index 02bd576a89c1..ff400317a0bc 100644
--- a/Documentation/user/watchdog.rst
+++ b/Documentation/user/watchdog.rst
@@ -57,6 +57,9 @@ measured in seconds:
   barebox@DPTechnics DPT-Module:/ devinfo wdog0
     autoping: 1 (type: bool)
+    priority: 100 (type: uint32)
+    running: 1 (type: enum) (values: "unknown", "1", "0")
+    seconds_to_expire: 7 (type: uint32)
     timeout_cur: 7 (type: uint32)
     timeout_max: 10 (type: uint32)
@@ -67,6 +70,34 @@ Use barebox' environment to persist these changes between reboots:
   nv dev.wdog0.autoping=1
   nv dev.wdog0.timeout_cur=7
+Watchdog State
+To check whether a watchdog is currently running, the ``running`` device
+parameter can be consulted. Not all watchdog devices (or their drivers)
+provide the information whether a watchdog was running prior to barebox.
+In that case, the parameter will contain the value ``unknown``.
+Watchdogs started by barebox can be monitored using the
+``seconds_to_expire`` parameter. A well-behaving system of watchdog
+device, watchdog driver and clocksource should reset as soon as the
+count down reaches zero.
+To manually start a watchdog, :ref:`command_wd` can be used.
+Default Watchdog
+barebox supports multiple concurrent watchdogs. The default watchdog used
+with :ref:`command_wd`, ``boot.watchdog_timeout`` and :ref:`command_boot`'s
+``-w`` option is the one with the highest positive priority.
+If multiple watchdogs share the same priority, only one will be affected.
+The priority is initially set by drivers and can be overridden in the
+device tree or via the ``priority`` device parameter. Normally, watchdogs
+that have a wider effect should be given the higher priority (e.g.
+PMIC watchdog resetting the board vs. SoC's watchdog resetting only itself).
 Boot Watchdog Timeout
@@ -85,7 +116,4 @@ or persistently by
   nv boot.watchdog_timeout=10
 where the used value again is measured in seconds.
-On a system with multiple watchdogs, the watchdog with the highest positive
-priority is the one affected by the ``boot.watchdog_timeout`` parameter.  If
-multiple watchdogs share the same priority, only one will be started.
+Only the default watchdog will be started.

barebox mailing list

  reply	other threads:[~2021-04-26 11:35 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-26 11:34 [PATCH master 1/2] sandbox: watchdog: don't return positive values from set_timeout Ahmad Fatoum
2021-04-26 11:34 ` Ahmad Fatoum [this message]
2021-05-03 10:38 ` Sascha Hauer

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \ \ \ \ \

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox