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;
* 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.
* 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.
Most people will say N.
+comment "Watchdog Pretimeout Governors"
+
+config WATCHDOG_PRETIMEOUT_GOV
+ bool "Enable watchdog pretimeout governors"
+ help
+ The option allows to select watchdog pretimeout governors.
+
endif # WATCHDOG
#
# The WatchDog Timer Driver Core.
-watchdog-objs += watchdog_core.o watchdog_dev.o
obj-$(CONFIG_WATCHDOG_CORE) += watchdog.o
+watchdog-objs += watchdog_core.o watchdog_dev.o
+
+watchdog-$(CONFIG_WATCHDOG_PRETIMEOUT_GOV) += watchdog_pretimeout.o
+
# Only one watchdog can succeed. We probe the ISA/PCI/USB based
# watchdog-cards first, then the architecture specific watchdog
# drivers and then the architecture independent "softdog" driver.
#include <linux/uaccess.h> /* For copy_to_user/put_user/... */
#include "watchdog_core.h"
+#include "watchdog_pretimeout.h"
/*
* struct watchdog_core_data - watchdog core internal data
}
static DEVICE_ATTR_RO(state);
+static ssize_t pretimeout_governor_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct watchdog_device *wdd = dev_get_drvdata(dev);
+
+ return watchdog_pretimeout_governor_get(wdd, buf);
+}
+static DEVICE_ATTR_RO(pretimeout_governor);
+
static umode_t wdt_is_visible(struct kobject *kobj, struct attribute *attr,
int n)
{
else if (attr == &dev_attr_pretimeout.attr &&
!(wdd->info->options & WDIOF_PRETIMEOUT))
mode = 0;
+ else if (attr == &dev_attr_pretimeout_governor.attr &&
+ (!(wdd->info->options & WDIOF_PRETIMEOUT) ||
+ !IS_ENABLED(CONFIG_WATCHDOG_PRETIMEOUT_GOV)))
+ mode = 0;
return mode;
}
&dev_attr_bootstatus.attr,
&dev_attr_status.attr,
&dev_attr_nowayout.attr,
+ &dev_attr_pretimeout_governor.attr,
NULL,
};
return PTR_ERR(dev);
}
+ ret = watchdog_register_pretimeout(wdd);
+ if (ret) {
+ device_destroy(&watchdog_class, devno);
+ watchdog_cdev_unregister(wdd);
+ }
+
return ret;
}
void watchdog_dev_unregister(struct watchdog_device *wdd)
{
+ watchdog_unregister_pretimeout(wdd);
device_destroy(&watchdog_class, wdd->wd_data->cdev.dev);
watchdog_cdev_unregister(wdd);
}
--- /dev/null
+/*
+ * Copyright (C) 2015-2016 Mentor Graphics
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ */
+
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/watchdog.h>
+
+#include "watchdog_pretimeout.h"
+
+/* Default watchdog pretimeout governor */
+static struct watchdog_governor *default_gov;
+
+/* The spinlock protects default_gov, wdd->gov and pretimeout_list */
+static DEFINE_SPINLOCK(pretimeout_lock);
+
+/* List of watchdog devices, which can generate a pretimeout event */
+static LIST_HEAD(pretimeout_list);
+
+struct watchdog_pretimeout {
+ struct watchdog_device *wdd;
+ struct list_head entry;
+};
+
+int watchdog_pretimeout_governor_get(struct watchdog_device *wdd, char *buf)
+{
+ int count = 0;
+
+ spin_lock_irq(&pretimeout_lock);
+ if (wdd->gov)
+ count = sprintf(buf, "%s\n", wdd->gov->name);
+ spin_unlock_irq(&pretimeout_lock);
+
+ return count;
+}
+
+void watchdog_notify_pretimeout(struct watchdog_device *wdd)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&pretimeout_lock, flags);
+ if (!wdd->gov) {
+ spin_unlock_irqrestore(&pretimeout_lock, flags);
+ return;
+ }
+
+ wdd->gov->pretimeout(wdd);
+ spin_unlock_irqrestore(&pretimeout_lock, flags);
+}
+EXPORT_SYMBOL_GPL(watchdog_notify_pretimeout);
+
+int watchdog_register_governor(struct watchdog_governor *gov)
+{
+ struct watchdog_pretimeout *p;
+
+ if (!default_gov) {
+ spin_lock_irq(&pretimeout_lock);
+ default_gov = gov;
+
+ list_for_each_entry(p, &pretimeout_list, entry)
+ if (!p->wdd->gov)
+ p->wdd->gov = default_gov;
+ spin_unlock_irq(&pretimeout_lock);
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(watchdog_register_governor);
+
+void watchdog_unregister_governor(struct watchdog_governor *gov)
+{
+ struct watchdog_pretimeout *p;
+
+ spin_lock_irq(&pretimeout_lock);
+ if (gov == default_gov)
+ default_gov = NULL;
+
+ list_for_each_entry(p, &pretimeout_list, entry)
+ if (p->wdd->gov == gov)
+ p->wdd->gov = default_gov;
+ spin_unlock_irq(&pretimeout_lock);
+}
+EXPORT_SYMBOL(watchdog_unregister_governor);
+
+int watchdog_register_pretimeout(struct watchdog_device *wdd)
+{
+ struct watchdog_pretimeout *p;
+
+ if (!(wdd->info->options & WDIOF_PRETIMEOUT))
+ return 0;
+
+ p = kzalloc(sizeof(*p), GFP_KERNEL);
+ if (!p)
+ return -ENOMEM;
+
+ spin_lock_irq(&pretimeout_lock);
+ list_add(&p->entry, &pretimeout_list);
+ p->wdd = wdd;
+ wdd->gov = default_gov;
+ spin_unlock_irq(&pretimeout_lock);
+
+ return 0;
+}
+
+void watchdog_unregister_pretimeout(struct watchdog_device *wdd)
+{
+ struct watchdog_pretimeout *p, *t;
+
+ if (!(wdd->info->options & WDIOF_PRETIMEOUT))
+ return;
+
+ spin_lock_irq(&pretimeout_lock);
+ wdd->gov = NULL;
+
+ list_for_each_entry_safe(p, t, &pretimeout_list, entry) {
+ if (p->wdd == wdd) {
+ list_del(&p->entry);
+ break;
+ }
+ }
+ spin_unlock_irq(&pretimeout_lock);
+
+ kfree(p);
+}
--- /dev/null
+#ifndef __WATCHDOG_PRETIMEOUT_H
+#define __WATCHDOG_PRETIMEOUT_H
+
+#define WATCHDOG_GOV_NAME_MAXLEN 20
+
+struct watchdog_device;
+
+struct watchdog_governor {
+ const char name[WATCHDOG_GOV_NAME_MAXLEN];
+ void (*pretimeout)(struct watchdog_device *wdd);
+};
+
+#if IS_ENABLED(CONFIG_WATCHDOG_PRETIMEOUT_GOV)
+/* Interfaces to watchdog pretimeout governors */
+int watchdog_register_governor(struct watchdog_governor *gov);
+void watchdog_unregister_governor(struct watchdog_governor *gov);
+
+/* Interfaces to watchdog_dev.c */
+int watchdog_register_pretimeout(struct watchdog_device *wdd);
+void watchdog_unregister_pretimeout(struct watchdog_device *wdd);
+int watchdog_pretimeout_governor_get(struct watchdog_device *wdd, char *buf);
+
+#else
+static inline int watchdog_register_pretimeout(struct watchdog_device *wdd)
+{
+ return 0;
+}
+
+static inline void watchdog_unregister_pretimeout(struct watchdog_device *wdd)
+{
+}
+
+static inline int watchdog_pretimeout_governor_get(struct watchdog_device *wdd,
+ char *buf)
+{
+ return -EINVAL;
+}
+#endif
+
+#endif
struct watchdog_ops;
struct watchdog_device;
struct watchdog_core_data;
+struct watchdog_governor;
/** struct watchdog_ops - The watchdog-devices operations
*
* watchdog device.
* @info: Pointer to a watchdog_info structure.
* @ops: Pointer to the list of watchdog operations.
+ * @gov: Pointer to watchdog pretimeout governor.
* @bootstatus: Status of the watchdog device at boot.
* @timeout: The watchdog devices timeout value (in seconds).
* @pretimeout: The watchdog devices pre_timeout value.
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;
return wdd->driver_data;
}
+/* Use the following functions to report watchdog pretimeout event */
+#if IS_ENABLED(CONFIG_WATCHDOG_PRETIMEOUT_GOV)
+void watchdog_notify_pretimeout(struct watchdog_device *wdd);
+#else
+static inline void watchdog_notify_pretimeout(struct watchdog_device *wdd)
+{
+ pr_alert("watchdog%d: pretimeout event\n", wdd->id);
+}
+#endif
+
/* 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,
projects / cascardo / linux.git / commitdiff