feat(plat/zynqmp): add SDEI support

Add basic SDEI support, implementing the software event 0 only for now.
This already allows hypervisors like Jailhouse to use SDEI for internal
signaling while passing the GICC through to the guest (see also IMX8).

With SDEI on, we overrun the SRAM and need to stay in DRAM. So keep SDEI
off by default.

Co-developed-by: Angelo Ruocco <angeloruocco90@gmail.com>
Signed-off-by: Angelo Ruocco <angeloruocco90@gmail.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Change-Id: Ic0d71b4ef0978c0a34393f4e3530ed1e24a39ca2
diff --git a/plat/xilinx/zynqmp/zynqmp_sdei.c b/plat/xilinx/zynqmp/zynqmp_sdei.c
new file mode 100644
index 0000000..7e92b58
--- /dev/null
+++ b/plat/xilinx/zynqmp/zynqmp_sdei.c
@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2017-2020, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) Siemens AG, 2020-2021
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+/* SDEI configuration for ARM platforms */
+
+#include <bl31/ehf.h>
+#include <common/debug.h>
+#include <services/sdei.h>
+
+#include <plat/common/platform.h>
+#include <platform_def.h>
+
+int arm_validate_ns_entrypoint(uintptr_t entrypoint)
+{
+	return (entrypoint < BL31_BASE || entrypoint > BL31_LIMIT) ? 0 : -1;
+}
+
+/* Private event mappings */
+static sdei_ev_map_t zynqmp_sdei_private[] = {
+	SDEI_DEFINE_EVENT_0(ZYNQMP_SDEI_SGI_PRIVATE),
+};
+
+/* Shared event mappings */
+static sdei_ev_map_t zynqmp_sdei_shared[] = {
+};
+
+void plat_sdei_setup(void)
+{
+	INFO("SDEI platform setup\n");
+}
+
+/* Export ARM SDEI events */
+REGISTER_SDEI_MAP(zynqmp_sdei_private, zynqmp_sdei_shared);