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authorJean-Baptiste Theou <jtheou@adeneo-embedded.us>2015-06-09 19:55:02 +0300
committerWim Van Sebroeck <wim@iguana.be>2015-06-29 12:51:06 +0300
commitef90174f821041313d42d99c1c8b35a3af64a910 (patch)
tree0265d89b6ee866b7e20a8925fae03e290e078e00 /Documentation
parentb9be9660ba2d23259e4a430a44167ef441dc5fe6 (diff)
downloadlinux-ef90174f821041313d42d99c1c8b35a3af64a910.tar.xz
watchdog: watchdog_core: Add watchdog registration deferral mechanism
Currently, watchdog subsystem require the misc subsystem to register a watchdog. This may not be the case in case of an early registration of a watchdog, which can be required when the watchdog cannot be disabled. This patch introduces a deferral mechanism to remove this requirement. Signed-off-by: Jean-Baptiste Theou <jtheou@adeneo-embedded.us> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/watchdog/watchdog-kernel-api.txt7
1 files changed, 7 insertions, 0 deletions
diff --git a/Documentation/watchdog/watchdog-kernel-api.txt b/Documentation/watchdog/watchdog-kernel-api.txt
index a0438f3957ca..d8b0d3367706 100644
--- a/Documentation/watchdog/watchdog-kernel-api.txt
+++ b/Documentation/watchdog/watchdog-kernel-api.txt
@@ -36,6 +36,10 @@ The watchdog_unregister_device routine deregisters a registered watchdog timer
device. The parameter of this routine is the pointer to the registered
watchdog_device structure.
+The watchdog subsystem includes an registration deferral mechanism,
+which allows you to register an watchdog as early as you wish during
+the boot process.
+
The watchdog device structure looks like this:
struct watchdog_device {
@@ -52,6 +56,7 @@ struct watchdog_device {
void *driver_data;
struct mutex lock;
unsigned long status;
+ struct list_head deferred;
};
It contains following fields:
@@ -80,6 +85,8 @@ It contains following fields:
information about the status of the device (Like: is the watchdog timer
running/active, is the nowayout bit set, is the device opened via
the /dev/watchdog interface or not, ...).
+* deferred: entry in wtd_deferred_reg_list which is used to
+ register early initialized watchdogs.
The list of watchdog operations is defined as: