diff --git a/include/linux/mlx4/doorbell.h b/include/linux/mlx4/doorbell.h
new file mode 100644
index 0000000..3f2da44
--- /dev/null
+++ b/include/linux/mlx4/doorbell.h
@@ -0,0 +1,97 @@
+/*
+ * Copyright (c) 2004 Topspin Communications.  All rights reserved.
+ * Copyright (c) 2005 Sun Microsystems, Inc. All rights reserved.
+ * Copyright (c) 2005 Mellanox Technologies. All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses.  You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ *     Redistribution and use in source and binary forms, with or
+ *     without modification, are permitted provided that the following
+ *     conditions are met:
+ *
+ *      - Redistributions of source code must retain the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer.
+ *
+ *      - 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.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#ifndef MLX4_DOORBELL_H
+#define MLX4_DOORBELL_H
+
+#include <linux/types.h>
+#include <linux/io.h>
+
+#define MLX4_SEND_DOORBELL    0x14
+#define MLX4_CQ_DOORBELL      0x20
+
+#if BITS_PER_LONG == 64
+/*
+ * Assume that we can just write a 64-bit doorbell atomically.  s390
+ * actually doesn't have writeq() but S/390 systems don't even have
+ * PCI so we won't worry about it.
+ */
+
+#define MLX4_DECLARE_DOORBELL_LOCK(name)
+#define MLX4_INIT_DOORBELL_LOCK(ptr)    do { } while (0)
+#define MLX4_GET_DOORBELL_LOCK(ptr)      (NULL)
+
+static inline void mlx4_write64_raw(__be64 val, void __iomem *dest)
+{
+	__raw_writeq((__force u64) val, dest);
+}
+
+static inline void mlx4_write64(__be32 val[2], void __iomem *dest,
+				spinlock_t *doorbell_lock)
+{
+	__raw_writeq(*(u64 *) val, dest);
+}
+
+#else
+
+/*
+ * Just fall back to a spinlock to protect the doorbell if
+ * BITS_PER_LONG is 32 -- there's no portable way to do atomic 64-bit
+ * MMIO writes.
+ */
+
+#define MLX4_DECLARE_DOORBELL_LOCK(name) spinlock_t name;
+#define MLX4_INIT_DOORBELL_LOCK(ptr)     spin_lock_init(ptr)
+#define MLX4_GET_DOORBELL_LOCK(ptr)      (ptr)
+
+static inline void mlx4_write64_raw(__be64 val, void __iomem *dest)
+{
+	__raw_writel(((__force u32 *) &val)[0], dest);
+	__raw_writel(((__force u32 *) &val)[1], dest + 4);
+}
+
+static inline void mlx4_write64(__be32 val[2], void __iomem *dest,
+				spinlock_t *doorbell_lock)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(doorbell_lock, flags);
+	__raw_writel((__force u32) val[0], dest);
+	__raw_writel((__force u32) val[1], dest + 4);
+	spin_unlock_irqrestore(doorbell_lock, flags);
+}
+
+#endif
+
+#endif /* MLX4_DOORBELL_H */