feat(versal2): add support for AMD Versal Gen 2 platform

New SoC is a78 based with gicv3 and uart over pl011. Communication
interfaces are similar to Versal NET platform. System starts with AMD PLM
firmware which loads TF-A(bl31) to memory, which is already configured, and
jumps to it. PLM also prepare handoff structure for TF-A with information
what components were load and flags which indicate which EL level SW should
be started.

Change-Id: I5065b1b7ec4ee58e77dc4096747758480c84009c
Signed-off-by: Amit Nagal <amit.nagal@amd.com>
Signed-off-by: Akshay Belsare <akshay.belsare@amd.com>
Signed-off-by: Michal Simek <michal.simek@amd.com>
diff --git a/plat/amd/versal2/aarch64/helpers.S b/plat/amd/versal2/aarch64/helpers.S
new file mode 100644
index 0000000..580bb76
--- /dev/null
+++ b/plat/amd/versal2/aarch64/helpers.S
@@ -0,0 +1,68 @@
+/*
+ * Copyright (c) 2018-2021, Arm Limited and Contributors. All rights reserved.
+ * Copyright (c) 2018-2022, Xilinx, Inc. All rights reserved.
+ * Copyright (c) 2022-2024, Advanced Micro Devices, Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <arch.h>
+#include <asm_macros.S>
+#include <drivers/arm/gicv3.h>
+
+#include <platform_def.h>
+
+	.globl	plat_secondary_cold_boot_setup
+	.globl	plat_is_my_cpu_primary
+	.globl	platform_mem_init
+	.globl	plat_my_core_pos
+
+	/* -----------------------------------------------------
+	 * void plat_secondary_cold_boot_setup (void);
+	 *
+	 * This function performs any platform specific actions
+	 * needed for a secondary cpu after a cold reset e.g
+	 * mark the cpu's presence, mechanism to place it in a
+	 * holding pen etc.
+	 * TODO: Should we read the PSYS register to make sure
+	 * that the request has gone through.
+	 * -----------------------------------------------------
+	 */
+func plat_secondary_cold_boot_setup
+	mrs	x0, mpidr_el1
+
+	/*
+	 * There is no sane reason to come out of this wfi. This
+	 * cpu will be powered on and reset by the cpu_on pm api
+	 */
+	dsb	sy
+	bl	plat_panic_handler
+endfunc plat_secondary_cold_boot_setup
+
+func plat_is_my_cpu_primary
+	mov	x9, x30
+	bl	plat_my_core_pos
+	cmp	x0, #PRIMARY_CPU
+	cset	x0, eq
+	ret	x9
+endfunc plat_is_my_cpu_primary
+
+	/* -----------------------------------------------------
+	 *  unsigned int plat_my_core_pos(void)
+	 *  This function uses the plat_core_pos_by_mpidr()
+	 *  definition to get the index of the calling CPU.
+	 * -----------------------------------------------------
+	 */
+func plat_my_core_pos
+	mrs	x0, mpidr_el1
+	b	plat_core_pos_by_mpidr
+endfunc plat_my_core_pos
+
+	/* ---------------------------------------------------------------------
+	 * We don't need to carry out any memory initialization on platform
+	 * The Secure RAM is accessible straight away.
+	 * ---------------------------------------------------------------------
+	 */
+func platform_mem_init
+	ret
+endfunc platform_mem_init