1 files changed, 125 insertions, 0 deletions
diff --git a/drivers/tee/optee/notif.c b/drivers/tee/optee/notif.c
new file mode 100644
index 000000000000..a28fa03dcd0e
--- /dev/null
+++ b/drivers/tee/optee/notif.c
@@ -0,0 +1,125 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2015-2021, Linaro Limited
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/arm-smccc.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/tee_drv.h>
+#include "optee_private.h"
+
+struct notif_entry {
+	struct list_head link;
+	struct completion c;
+	u_int key;
+};
+
+static bool have_key(struct optee *optee, u_int key)
+{
+	struct notif_entry *entry;
+
+	list_for_each_entry(entry, &optee->notif.db, link)
+		if (entry->key == key)
+			return true;
+
+	return false;
+}
+
+int optee_notif_wait(struct optee *optee, u_int key)
+{
+	unsigned long flags;
+	struct notif_entry *entry;
+	int rc = 0;
+
+	if (key > optee->notif.max_key)
+		return -EINVAL;
+
+	entry = kmalloc(sizeof(*entry), GFP_KERNEL);
+	if (!entry)
+		return -ENOMEM;
+	init_completion(&entry->c);
+	entry->key = key;
+
+	spin_lock_irqsave(&optee->notif.lock, flags);
+
+	/*
+	 * If the bit is already set it means that the key has already
+	 * been posted and we must not wait.
+	 */
+	if (test_bit(key, optee->notif.bitmap)) {
+		clear_bit(key, optee->notif.bitmap);
+		goto out;
+	}
+
+	/*
+	 * Check if someone is already waiting for this key. If there is
+	 * it's a programming error.
+	 */
+	if (have_key(optee, key)) {
+		rc = -EBUSY;
+		goto out;
+	}
+
+	list_add_tail(&entry->link, &optee->notif.db);
+
+	/*
+	 * Unlock temporarily and wait for completion.
+	 */
+	spin_unlock_irqrestore(&optee->notif.lock, flags);
+	wait_for_completion(&entry->c);
+	spin_lock_irqsave(&optee->notif.lock, flags);
+
+	list_del(&entry->link);
+out:
+	spin_unlock_irqrestore(&optee->notif.lock, flags);
+
+	kfree(entry);
+
+	return rc;
+}
+
+int optee_notif_send(struct optee *optee, u_int key)
+{
+	unsigned long flags;
+	struct notif_entry *entry;
+
+	if (key > optee->notif.max_key)
+		return -EINVAL;
+
+	spin_lock_irqsave(&optee->notif.lock, flags);
+
+	list_for_each_entry(entry, &optee->notif.db, link)
+		if (entry->key == key) {
+			complete(&entry->c);
+			goto out;
+		}
+
+	/* Only set the bit in case there where nobody waiting */
+	set_bit(key, optee->notif.bitmap);
+out:
+	spin_unlock_irqrestore(&optee->notif.lock, flags);
+
+	return 0;
+}
+
+int optee_notif_init(struct optee *optee, u_int max_key)
+{
+	spin_lock_init(&optee->notif.lock);
+	INIT_LIST_HEAD(&optee->notif.db);
+	optee->notif.bitmap = bitmap_zalloc(max_key, GFP_KERNEL);
+	if (!optee->notif.bitmap)
+		return -ENOMEM;
+
+	optee->notif.max_key = max_key;
+
+	return 0;
+}
+
+void optee_notif_uninit(struct optee *optee)
+{
+	kfree(optee->notif.bitmap);
+}