1 files changed, 156 insertions, 0 deletions
diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_util.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_util.c
new file mode 100644
index 000000000000..384acb8d2eae
--- /dev/null
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_util.c
@@ -0,0 +1,156 @@
+/**
+ * Copyright (c) 2010-2012 Broadcom. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions, and the following disclaimer,
+ *    without modification.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The names of the above-listed copyright holders may not be used
+ *    to endorse or promote products derived from this software without
+ *    specific prior written permission.
+ *
+ * ALTERNATIVELY, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") version 2, as published by the Free
+ * Software Foundation.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+ * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "vchiq_util.h"
+#include "vchiq_killable.h"
+
+static inline int is_pow2(int i)
+{
+	return i && !(i & (i - 1));
+}
+
+int vchiu_queue_init(VCHIU_QUEUE_T *queue, int size)
+{
+	WARN_ON(!is_pow2(size));
+
+	queue->size = size;
+	queue->read = 0;
+	queue->write = 0;
+	queue->initialized = 1;
+
+	sema_init(&queue->pop, 0);
+	sema_init(&queue->push, 0);
+
+	queue->storage = kzalloc(size * sizeof(VCHIQ_HEADER_T *), GFP_KERNEL);
+	if (queue->storage == NULL) {
+		vchiu_queue_delete(queue);
+		return 0;
+	}
+	return 1;
+}
+
+void vchiu_queue_delete(VCHIU_QUEUE_T *queue)
+{
+	if (queue->storage != NULL)
+		kfree(queue->storage);
+}
+
+int vchiu_queue_is_empty(VCHIU_QUEUE_T *queue)
+{
+	return queue->read == queue->write;
+}
+
+int vchiu_queue_is_full(VCHIU_QUEUE_T *queue)
+{
+	return queue->write == queue->read + queue->size;
+}
+
+void vchiu_queue_push(VCHIU_QUEUE_T *queue, VCHIQ_HEADER_T *header)
+{
+	if (!queue->initialized)
+		return;
+
+	while (queue->write == queue->read + queue->size) {
+		if (down_interruptible(&queue->pop) != 0) {
+			flush_signals(current);
+		}
+	}
+
+	/*
+	 * Write to queue->storage must be visible after read from
+	 * queue->read
+	 */
+	smp_mb();
+
+	queue->storage[queue->write & (queue->size - 1)] = header;
+
+	/*
+	 * Write to queue->storage must be visible before write to
+	 * queue->write
+	 */
+	smp_wmb();
+
+	queue->write++;
+
+	up(&queue->push);
+}
+
+VCHIQ_HEADER_T *vchiu_queue_peek(VCHIU_QUEUE_T *queue)
+{
+	while (queue->write == queue->read) {
+		if (down_interruptible(&queue->push) != 0) {
+			flush_signals(current);
+		}
+	}
+
+	up(&queue->push); // We haven't removed anything from the queue.
+
+	/*
+	 * Read from queue->storage must be visible after read from
+	 * queue->write
+	 */
+	smp_rmb();
+
+	return queue->storage[queue->read & (queue->size - 1)];
+}
+
+VCHIQ_HEADER_T *vchiu_queue_pop(VCHIU_QUEUE_T *queue)
+{
+	VCHIQ_HEADER_T *header;
+
+	while (queue->write == queue->read) {
+		if (down_interruptible(&queue->push) != 0) {
+			flush_signals(current);
+		}
+	}
+
+	/*
+	 * Read from queue->storage must be visible after read from
+	 * queue->write
+	 */
+	smp_rmb();
+
+	header = queue->storage[queue->read & (queue->size - 1)];
+
+	/*
+	 * Read from queue->storage must be visible before write to
+	 * queue->read
+	 */
+	smp_mb();
+
+	queue->read++;
+
+	up(&queue->pop);
+
+	return header;
+}