Tegra: gpcdma: driver for general purpose DMA

This patch adds the driver for the general purpose DMA hardware
block on newer Tegra SoCs. The GPCDMA is a special purpose DMA
used to speed up memory copy operations to/from DRAM and TZSRAM.

This patch introduces a macro 'USE_GPC_DMA' to allow platforms
to override CPU based memory operations.

Change-Id: I3170d409c83b77e785437b1002a8d70188fabbeb
Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>
diff --git a/plat/nvidia/tegra/include/drivers/gpcdma.h b/plat/nvidia/tegra/include/drivers/gpcdma.h
new file mode 100644
index 0000000..fb5486a
--- /dev/null
+++ b/plat/nvidia/tegra/include/drivers/gpcdma.h
@@ -0,0 +1,16 @@
+/*
+ * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef __GPCDMA_H__
+#define __GPCDMA_H__
+
+#include <stdint.h>
+
+void tegra_gpcdma_memcpy(uint64_t dst_addr, uint64_t src_addr,
+			    uint32_t num_bytes);
+void tegra_gpcdma_zeromem(uint64_t dst_addr, uint32_t num_bytes);
+
+#endif /* __GPCDMA_H__ */