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path: root/drivers/tee/optee/notif.c
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Diffstat (limited to 'drivers/tee/optee/notif.c')
-rw-r--r--drivers/tee/optee/notif.c125
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 000000000..05212842b
--- /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)
+{
+ bitmap_free(optee->notif.bitmap);
+}