Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

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);
+}