Add support for Xilinx Zynq UltraScale+ MPSOC

The Xilinx Zynq UltraScale+ MPSOC containes a quad A53 cluster. This
patch adds the platform port for that SoC.

Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
diff --git a/plat/xilinx/zynqmp/aarch64/zynqmp_helpers.S b/plat/xilinx/zynqmp/aarch64/zynqmp_helpers.S
new file mode 100644
index 0000000..0afed47
--- /dev/null
+++ b/plat/xilinx/zynqmp/aarch64/zynqmp_helpers.S
@@ -0,0 +1,73 @@
+/*
+ * Copyright (c) 2013-2016, ARM Limited and Contributors. All rights reserved.
+ *
+ * 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.
+ *
+ * Neither the name of ARM nor the names of its contributors may be used
+ * to endorse or promote products derived from this software without specific
+ * prior written permission.
+ *
+ * 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 HOLDER 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 <asm_macros.S>
+#include <gicv2.h>
+#include <platform_def.h>
+
+	.globl	plat_secondary_cold_boot_setup
+	.globl	plat_is_my_cpu_primary
+
+	/* -----------------------------------------------------
+	 * 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
+
+	/* Deactivate the gic cpu interface */
+	ldr	x1, =BASE_GICC_BASE
+	mov	w0, #(IRQ_BYP_DIS_GRP1 | FIQ_BYP_DIS_GRP1)
+	orr	w0, w0, #(IRQ_BYP_DIS_GRP0 | FIQ_BYP_DIS_GRP0)
+	str	w0, [x1, #GICC_CTLR]
+
+	/*
+	 * 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
+1:
+	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, #ZYNQMP_PRIMARY_CPU
+	cset	x0, eq
+	ret	x9
+endfunc plat_is_my_cpu_primary