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89873a711d
The change adds an option to a user with CONFIG_WATCHDOG_SYSFS and CONFIG_WATCHDOG_PRETIMEOUT_GOV enabled to get information about all registered watchdog pretimeout governors by reading watchdog device attribute named "pretimeout_available_governors". Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
221 lines
4.7 KiB
C
221 lines
4.7 KiB
C
/*
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* Copyright (C) 2015-2016 Mentor Graphics
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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*/
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#include <linux/list.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <linux/string.h>
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#include <linux/watchdog.h>
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#include "watchdog_pretimeout.h"
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/* Default watchdog pretimeout governor */
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static struct watchdog_governor *default_gov;
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/* The spinlock protects default_gov, wdd->gov and pretimeout_list */
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static DEFINE_SPINLOCK(pretimeout_lock);
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/* List of watchdog devices, which can generate a pretimeout event */
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static LIST_HEAD(pretimeout_list);
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struct watchdog_pretimeout {
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struct watchdog_device *wdd;
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struct list_head entry;
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};
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/* The mutex protects governor list and serializes external interfaces */
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static DEFINE_MUTEX(governor_lock);
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/* List of the registered watchdog pretimeout governors */
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static LIST_HEAD(governor_list);
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struct governor_priv {
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struct watchdog_governor *gov;
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struct list_head entry;
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};
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static struct governor_priv *find_governor_by_name(const char *gov_name)
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{
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struct governor_priv *priv;
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list_for_each_entry(priv, &governor_list, entry)
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if (sysfs_streq(gov_name, priv->gov->name))
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return priv;
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return NULL;
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}
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int watchdog_pretimeout_available_governors_get(char *buf)
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{
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struct governor_priv *priv;
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int count = 0;
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mutex_lock(&governor_lock);
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list_for_each_entry(priv, &governor_list, entry)
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count += sprintf(buf + count, "%s\n", priv->gov->name);
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mutex_unlock(&governor_lock);
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return count;
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}
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int watchdog_pretimeout_governor_get(struct watchdog_device *wdd, char *buf)
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{
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int count = 0;
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spin_lock_irq(&pretimeout_lock);
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if (wdd->gov)
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count = sprintf(buf, "%s\n", wdd->gov->name);
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spin_unlock_irq(&pretimeout_lock);
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return count;
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}
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int watchdog_pretimeout_governor_set(struct watchdog_device *wdd,
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const char *buf)
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{
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struct governor_priv *priv;
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mutex_lock(&governor_lock);
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priv = find_governor_by_name(buf);
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if (!priv) {
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mutex_unlock(&governor_lock);
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return -EINVAL;
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}
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spin_lock_irq(&pretimeout_lock);
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wdd->gov = priv->gov;
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spin_unlock_irq(&pretimeout_lock);
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mutex_unlock(&governor_lock);
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return 0;
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}
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void watchdog_notify_pretimeout(struct watchdog_device *wdd)
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{
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unsigned long flags;
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spin_lock_irqsave(&pretimeout_lock, flags);
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if (!wdd->gov) {
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spin_unlock_irqrestore(&pretimeout_lock, flags);
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return;
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}
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wdd->gov->pretimeout(wdd);
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spin_unlock_irqrestore(&pretimeout_lock, flags);
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}
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EXPORT_SYMBOL_GPL(watchdog_notify_pretimeout);
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int watchdog_register_governor(struct watchdog_governor *gov)
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{
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struct watchdog_pretimeout *p;
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struct governor_priv *priv;
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priv = kzalloc(sizeof(*priv), GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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mutex_lock(&governor_lock);
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if (find_governor_by_name(gov->name)) {
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mutex_unlock(&governor_lock);
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kfree(priv);
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return -EBUSY;
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}
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priv->gov = gov;
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list_add(&priv->entry, &governor_list);
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if (!strncmp(gov->name, WATCHDOG_PRETIMEOUT_DEFAULT_GOV,
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WATCHDOG_GOV_NAME_MAXLEN)) {
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spin_lock_irq(&pretimeout_lock);
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default_gov = gov;
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list_for_each_entry(p, &pretimeout_list, entry)
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if (!p->wdd->gov)
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p->wdd->gov = default_gov;
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spin_unlock_irq(&pretimeout_lock);
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}
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mutex_unlock(&governor_lock);
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return 0;
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}
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EXPORT_SYMBOL(watchdog_register_governor);
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void watchdog_unregister_governor(struct watchdog_governor *gov)
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{
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struct watchdog_pretimeout *p;
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struct governor_priv *priv, *t;
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mutex_lock(&governor_lock);
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list_for_each_entry_safe(priv, t, &governor_list, entry) {
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if (priv->gov == gov) {
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list_del(&priv->entry);
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kfree(priv);
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break;
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}
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}
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spin_lock_irq(&pretimeout_lock);
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list_for_each_entry(p, &pretimeout_list, entry)
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if (p->wdd->gov == gov)
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p->wdd->gov = default_gov;
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spin_unlock_irq(&pretimeout_lock);
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mutex_unlock(&governor_lock);
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}
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EXPORT_SYMBOL(watchdog_unregister_governor);
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int watchdog_register_pretimeout(struct watchdog_device *wdd)
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{
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struct watchdog_pretimeout *p;
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if (!(wdd->info->options & WDIOF_PRETIMEOUT))
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return 0;
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p = kzalloc(sizeof(*p), GFP_KERNEL);
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if (!p)
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return -ENOMEM;
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spin_lock_irq(&pretimeout_lock);
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list_add(&p->entry, &pretimeout_list);
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p->wdd = wdd;
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wdd->gov = default_gov;
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spin_unlock_irq(&pretimeout_lock);
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return 0;
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}
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void watchdog_unregister_pretimeout(struct watchdog_device *wdd)
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{
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struct watchdog_pretimeout *p, *t;
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if (!(wdd->info->options & WDIOF_PRETIMEOUT))
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return;
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spin_lock_irq(&pretimeout_lock);
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wdd->gov = NULL;
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list_for_each_entry_safe(p, t, &pretimeout_list, entry) {
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if (p->wdd == wdd) {
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list_del(&p->entry);
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break;
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}
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}
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spin_unlock_irq(&pretimeout_lock);
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kfree(p);
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}
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