diff options
Diffstat (limited to 'drivers/watchdog/watchdog_pretimeout.c')
| -rw-r--r-- | drivers/watchdog/watchdog_pretimeout.c | 220 |
1 files changed, 220 insertions, 0 deletions
diff --git a/drivers/watchdog/watchdog_pretimeout.c b/drivers/watchdog/watchdog_pretimeout.c new file mode 100644 index 000000000000..9db07bfb4334 --- /dev/null +++ b/drivers/watchdog/watchdog_pretimeout.c @@ -0,0 +1,220 @@ +/* + * 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/string.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; +}; + +/* The mutex protects governor list and serializes external interfaces */ +static DEFINE_MUTEX(governor_lock); + +/* List of the registered watchdog pretimeout governors */ +static LIST_HEAD(governor_list); + +struct governor_priv { + struct watchdog_governor *gov; + struct list_head entry; +}; + +static struct governor_priv *find_governor_by_name(const char *gov_name) +{ + struct governor_priv *priv; + + list_for_each_entry(priv, &governor_list, entry) + if (sysfs_streq(gov_name, priv->gov->name)) + return priv; + + return NULL; +} + +int watchdog_pretimeout_available_governors_get(char *buf) +{ + struct governor_priv *priv; + int count = 0; + + mutex_lock(&governor_lock); + + list_for_each_entry(priv, &governor_list, entry) + count += sprintf(buf + count, "%s\n", priv->gov->name); + + mutex_unlock(&governor_lock); + + return count; +} + +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; +} + +int watchdog_pretimeout_governor_set(struct watchdog_device *wdd, + const char *buf) +{ + struct governor_priv *priv; + + mutex_lock(&governor_lock); + + priv = find_governor_by_name(buf); + if (!priv) { + mutex_unlock(&governor_lock); + return -EINVAL; + } + + spin_lock_irq(&pretimeout_lock); + wdd->gov = priv->gov; + spin_unlock_irq(&pretimeout_lock); + + mutex_unlock(&governor_lock); + + return 0; +} + +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; + struct governor_priv *priv; + + priv = kzalloc(sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + mutex_lock(&governor_lock); + + if (find_governor_by_name(gov->name)) { + mutex_unlock(&governor_lock); + kfree(priv); + return -EBUSY; + } + + priv->gov = gov; + list_add(&priv->entry, &governor_list); + + if (!strncmp(gov->name, WATCHDOG_PRETIMEOUT_DEFAULT_GOV, + WATCHDOG_GOV_NAME_MAXLEN)) { + 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); + } + + mutex_unlock(&governor_lock); + + return 0; +} +EXPORT_SYMBOL(watchdog_register_governor); + +void watchdog_unregister_governor(struct watchdog_governor *gov) +{ + struct watchdog_pretimeout *p; + struct governor_priv *priv, *t; + + mutex_lock(&governor_lock); + + list_for_each_entry_safe(priv, t, &governor_list, entry) { + if (priv->gov == gov) { + list_del(&priv->entry); + kfree(priv); + break; + } + } + + spin_lock_irq(&pretimeout_lock); + list_for_each_entry(p, &pretimeout_list, entry) + if (p->wdd->gov == gov) + p->wdd->gov = default_gov; + spin_unlock_irq(&pretimeout_lock); + + mutex_unlock(&governor_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); +} |