feat: adding the diphda platform

This commit enables trusted-firmware-a with Trusted Board Boot support
for the Diphda 64-bit platform.

Diphda uses a FIP image located in the flash. The FIP contains the
following components:

- BL2
- BL31
- BL32
- BL32 SPMC manifest
- BL33
- The TBB certificates

The board boot relies on CoT (chain of trust). The trusted-firmware-a
BL2 is extracted from the FIP and verified by the Secure Enclave
processor. BL2 verification relies on the signature area at the
beginning of the BL2 image. This area is needed by the SecureEnclave
bootloader.

Then, the application processor is released from reset and starts by
executing BL2.

BL2 performs the actions described in the trusted-firmware-a TBB design
document.

Signed-off-by: Rui Miguel Silva <rui.silva@arm.com>
Signed-off-by: Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com>
Change-Id: Iddb1cb9c2a0324a9635e23821c210ac81dfc305d
diff --git a/plat/arm/board/diphda/common/diphda_pm.c b/plat/arm/board/diphda/common/diphda_pm.c
new file mode 100644
index 0000000..12b322e
--- /dev/null
+++ b/plat/arm/board/diphda/common/diphda_pm.c
@@ -0,0 +1,22 @@
+/*
+ * Copyright (c) 2021, Arm Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <lib/psci/psci.h>
+#include <plat/arm/common/plat_arm.h>
+
+/*******************************************************************************
+ * Export the platform handlers via plat_arm_psci_pm_ops. The ARM Standard
+ * platform layer will take care of registering the handlers with PSCI.
+ ******************************************************************************/
+plat_psci_ops_t plat_arm_psci_pm_ops = {
+	/* dummy struct */
+	.validate_ns_entrypoint = NULL
+};
+
+const plat_psci_ops_t *plat_arm_psci_override_pm_ops(plat_psci_ops_t *ops)
+{
+	return ops;
+}