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| author | Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com> | 2016-10-07 15:39:54 +0300 |
|---|---|---|
| committer | Wim Van Sebroeck <wim@iguana.be> | 2016-10-08 10:27:10 +0200 |
| commit | ff84136cb6a4943f489ad037fe93f43be0573c23 (patch) | |
| tree | bde99dc52bf4066e666681d280011d37d17d269a /Documentation/watchdog | |
| parent | fc113d54e9d7ef3296cdf2eff49c8ca0a3e5a482 (diff) | |
| download | lwn-ff84136cb6a4943f489ad037fe93f43be0573c23.tar.gz lwn-ff84136cb6a4943f489ad037fe93f43be0573c23.zip | |
watchdog: add watchdog pretimeout governor framework
The change adds a simple watchdog pretimeout framework infrastructure,
its purpose is to allow users to select a desired handling of watchdog
pretimeout events, which may be generated by some watchdog devices.
A user selects a default watchdog pretimeout governor during
compilation stage.
Watchdogs with WDIOF_PRETIMEOUT capability now have one more device
attribute in sysfs, pretimeout_governor attribute is intended to display
the selected watchdog pretimeout governor.
The framework has no impact at runtime on watchdog devices with no
WDIOF_PRETIMEOUT capability set.
Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Diffstat (limited to 'Documentation/watchdog')
| -rw-r--r-- | Documentation/watchdog/watchdog-kernel-api.txt | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/Documentation/watchdog/watchdog-kernel-api.txt b/Documentation/watchdog/watchdog-kernel-api.txt index 3402dcad5b03..ea277478982f 100644 --- a/Documentation/watchdog/watchdog-kernel-api.txt +++ b/Documentation/watchdog/watchdog-kernel-api.txt @@ -48,6 +48,7 @@ struct watchdog_device { const struct attribute_group **groups; const struct watchdog_info *info; const struct watchdog_ops *ops; + const struct watchdog_governor *gov; unsigned int bootstatus; unsigned int timeout; unsigned int pretimeout; @@ -75,6 +76,7 @@ It contains following fields: * info: a pointer to a watchdog_info structure. This structure gives some additional information about the watchdog timer itself. (Like it's unique name) * ops: a pointer to the list of watchdog operations that the watchdog supports. +* gov: a pointer to the assigned watchdog device pretimeout governor or NULL. * timeout: the watchdog timer's timeout value (in seconds). This is the time after which the system will reboot if user space does not send a heartbeat request if WDOG_ACTIVE is set. @@ -288,3 +290,14 @@ User should follow the following guidelines for setting the priority: * 128: default restart handler, use if no other handler is expected to be available, and/or if restart is sufficient to restart the entire system * 255: highest priority, will preempt all other restart handlers + +To raise a pretimeout notification, the following function should be used: + +void watchdog_notify_pretimeout(struct watchdog_device *wdd) + +The function can be called in the interrupt context. If watchdog pretimeout +governor framework (kbuild CONFIG_WATCHDOG_PRETIMEOUT_GOV symbol) is enabled, +an action is taken by a preconfigured pretimeout governor preassigned to +the watchdog device. If watchdog pretimeout governor framework is not +enabled, watchdog_notify_pretimeout() prints a notification message to +the kernel log buffer. |