Many watchdog drivers implement the same code to register a restart
handler. This patch provides a generic way to set such a function.
The patch adds a new restart watchdog operation. If a restart priority
greater than 0 is needed, the driver can call
watchdog_set_restart_priority to set it.
Signed-off-by: Damien Riegel <damien.riegel@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Vivien Didelot <vivien.didelot@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/watchdog/watchdog-kernel-api.txt | 2 ++
drivers/watchdog/watchdog_core.c | 35 ++++++++++++++++++++++++++
include/linux/watchdog.h | 5 ++++
3 files changed, 42 insertions(+)
diff --git a/Documentation/watchdog/watchdog-kernel-api.txt b/Documentation/watchdog/watchdog-kernel-api.txt
index d8b0d33..10e6132 100644
--- a/Documentation/watchdog/watchdog-kernel-api.txt
+++ b/Documentation/watchdog/watchdog-kernel-api.txt
@@ -100,6 +100,7 @@ struct watchdog_ops {
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);
@@ -164,6 +165,7 @@ they are supported. These optional routines/operations are:
(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.
* 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
diff --git a/drivers/watchdog/watchdog_core.c b/drivers/watchdog/watchdog_core.c
index 873f139..9c8a8e8 100644
--- a/drivers/watchdog/watchdog_core.c
+++ b/drivers/watchdog/watchdog_core.c
@@ -32,6 +32,7 @@
#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 */
@@ -137,6 +138,28 @@ int watchdog_init_timeout(struct watchdog_device *wdd,
}
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;
+}
+
+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;
@@ -202,6 +225,15 @@ static int __watchdog_register_device(struct watchdog_device *wdd)
return ret;
}
+ if (wdd->ops->restart) {
+ wdd->restart_nb.notifier_call = watchdog_restart_notifier;
+
+ ret = register_restart_handler(&wdd->restart_nb);
+ if (ret)
+ dev_err(wdd->dev, "Cannot register restart handler (%d)\n",
+ ret);
+ }
+
return 0;
}
@@ -238,6 +270,9 @@ static void __watchdog_unregister_device(struct watchdog_device *wdd)
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)
diff --git a/include/linux/watchdog.h b/include/linux/watchdog.h
index e90e3ea..e1a4dc4 100644
--- a/include/linux/watchdog.h
+++ b/include/linux/watchdog.h
@@ -26,6 +26,7 @@ struct watchdog_device;
* @status: The routine that shows the status of the watchdog device.
* @set_timeout:The routine for setting the watchdog devices timeout value.
* @get_timeleft:The routine that get's the time that's left before a reset.
+ * @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.
@@ -45,6 +46,7 @@ struct watchdog_ops {
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);
@@ -88,6 +90,7 @@ struct watchdog_device {
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;
@@ -142,6 +145,8 @@ static inline void *watchdog_get_drvdata(struct watchdog_device *wdd)
}
/* drivers/watchdog/watchdog_core.c */
+extern 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 *);
--
2.5.0
--
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