unsigned int timeout;
unsigned int min_timeout;
unsigned int max_timeout;
+ struct notifier_block restart_nb;
void *driver_data;
struct mutex lock;
unsigned long status;
* timeout: the watchdog timer's timeout value (in seconds).
* min_timeout: the watchdog timer's minimum timeout value (in seconds).
* max_timeout: the watchdog timer's maximum timeout value (in seconds).
+* restart_nb: notifier block that is registered for machine restart, for
+ internal use only. If a watchdog is capable of restarting the machine, it
+ should define ops->restart. Priority can be changed through
+ watchdog_set_restart_priority.
* bootstatus: status of the device after booting (reported with watchdog
WDIOF_* status bits).
* driver_data: a pointer to the drivers private data of a watchdog device.
unsigned int (*status)(struct watchdog_device *);
int (*set_timeout)(struct watchdog_device *, unsigned int);
unsigned int (*get_timeleft)(struct watchdog_device *);
+ int (*restart)(struct watchdog_device *);
void (*ref)(struct watchdog_device *);
void (*unref)(struct watchdog_device *);
long (*ioctl)(struct watchdog_device *, unsigned int, unsigned long);
(Note: the WDIOF_SETTIMEOUT needs to be set in the options field of the
watchdog's info structure).
* get_timeleft: this routines returns the time that's left before a reset.
+* restart: this routine restarts the machine. It returns 0 on success or a
+ negative errno code for failure.
* ref: the operation that calls kref_get on the kref of a dynamically
allocated watchdog_device struct.
* unref: the operation that calls kref_put on the kref of a dynamically
to set the default timeout value as timeout value in the watchdog_device and
then use this function to set the user "preferred" timeout value.
This routine returns zero on success and a negative errno code for failure.
+
+To change the priority of the restart handler the following helper should be
+used:
+
+void watchdog_set_restart_priority(struct watchdog_device *wdd, int priority);
+
+User should follow the following guidelines for setting the priority:
+* 0: should be called in last resort, has limited restart capabilities
+* 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
#include <linux/types.h> /* For standard types */
#include <linux/errno.h> /* For the -ENODEV/... values */
#include <linux/kernel.h> /* For printk/panic/... */
+#include <linux/reboot.h> /* For restart handler */
#include <linux/watchdog.h> /* For watchdog specific items */
#include <linux/init.h> /* For __init/__exit/... */
#include <linux/idr.h> /* For ida_* macros */
}
EXPORT_SYMBOL_GPL(watchdog_init_timeout);
+static int watchdog_restart_notifier(struct notifier_block *nb,
+ unsigned long action, void *data)
+{
+ struct watchdog_device *wdd = container_of(nb, struct watchdog_device,
+ restart_nb);
+
+ int ret;
+
+ ret = wdd->ops->restart(wdd);
+ if (ret)
+ return NOTIFY_BAD;
+
+ return NOTIFY_DONE;
+}
+
+/**
+ * watchdog_set_restart_priority - Change priority of restart handler
+ * @wdd: watchdog device
+ * @priority: priority of the restart handler, should follow these guidelines:
+ * 0: use watchdog's restart function as last resort, has limited restart
+ * capabilies
+ * 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: preempt all other handlers
+ *
+ * If a wdd->ops->restart function is provided when watchdog_register_device is
+ * called, it will be registered as a restart handler with the priority given
+ * here.
+ */
+void watchdog_set_restart_priority(struct watchdog_device *wdd, int priority)
+{
+ wdd->restart_nb.priority = priority;
+}
+EXPORT_SYMBOL_GPL(watchdog_set_restart_priority);
+
static int __watchdog_register_device(struct watchdog_device *wdd)
{
int ret, id = -1, devno;
return ret;
}
+ if (wdd->ops->restart) {
+ wdd->restart_nb.notifier_call = watchdog_restart_notifier;
+
+ ret = register_restart_handler(&wdd->restart_nb);
+ if (ret)
+ dev_warn(wdd->dev, "Cannot register restart handler (%d)\n",
+ ret);
+ }
+
return 0;
}
if (wdd == NULL)
return;
+ if (wdd->ops->restart)
+ unregister_restart_handler(&wdd->restart_nb);
+
devno = wdd->cdev.dev;
ret = watchdog_dev_unregister(wdd);
if (ret)
#include <linux/bitops.h>
#include <linux/device.h>
#include <linux/cdev.h>
+#include <linux/notifier.h>
#include <uapi/linux/watchdog.h>
struct watchdog_ops;
* @status: The routine that shows the status of the watchdog device.
* @set_timeout:The routine for setting the watchdog devices timeout value (in seconds).
* @get_timeleft:The routine that gets the time left before a reset (in seconds).
+ * @restart: The routine for restarting the machine.
* @ref: The ref operation for dyn. allocated watchdog_device structs
* @unref: The unref operation for dyn. allocated watchdog_device structs
* @ioctl: The routines that handles extra ioctl calls.
unsigned int (*status)(struct watchdog_device *);
int (*set_timeout)(struct watchdog_device *, unsigned int);
unsigned int (*get_timeleft)(struct watchdog_device *);
+ int (*restart)(struct watchdog_device *);
void (*ref)(struct watchdog_device *);
void (*unref)(struct watchdog_device *);
long (*ioctl)(struct watchdog_device *, unsigned int, unsigned long);
* @timeout: The watchdog devices timeout value (in seconds).
* @min_timeout:The watchdog devices minimum timeout value (in seconds).
* @max_timeout:The watchdog devices maximum timeout value (in seconds).
+ * @restart_nb: The notifier block to register a restart function.
* @driver-data:Pointer to the drivers private data.
* @lock: Lock for watchdog core internal use only.
* @status: Field that contains the devices internal status bits.
unsigned int timeout;
unsigned int min_timeout;
unsigned int max_timeout;
+ struct notifier_block restart_nb;
void *driver_data;
struct mutex lock;
unsigned long status;
}
/* drivers/watchdog/watchdog_core.c */
+void watchdog_set_restart_priority(struct watchdog_device *wdd, int priority);
extern int watchdog_init_timeout(struct watchdog_device *wdd,
unsigned int timeout_parm, struct device *dev);
extern int watchdog_register_device(struct watchdog_device *);