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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
commitace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch)
treeb2d64bc10158fdd5497876388cd68142ca374ed3 /drivers/watchdog/watchdog_pretimeout.c
parentInitial commit. (diff)
downloadlinux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz
linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/watchdog/watchdog_pretimeout.c')
-rw-r--r--drivers/watchdog/watchdog_pretimeout.c215
1 files changed, 215 insertions, 0 deletions
diff --git a/drivers/watchdog/watchdog_pretimeout.c b/drivers/watchdog/watchdog_pretimeout.c
new file mode 100644
index 0000000000..e5295c990f
--- /dev/null
+++ b/drivers/watchdog/watchdog_pretimeout.c
@@ -0,0 +1,215 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2015-2016 Mentor Graphics
+ */
+
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/string.h>
+#include <linux/watchdog.h>
+
+#include "watchdog_core.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 += sysfs_emit_at(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 = sysfs_emit(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 (!watchdog_have_pretimeout(wdd))
+ 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 (!watchdog_have_pretimeout(wdd))
+ 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);
+ kfree(p);
+ break;
+ }
+ }
+ spin_unlock_irq(&pretimeout_lock);
+}