feat(zynqmp): add support for custom sip service

Add support for custom sip service.
Bare minimum implementation for custom_smc_handler is provided
by platform. Actual definition for custom_smc_handler will be provided
by custom pkg.

This feature is going to be used by external libraries. For example
for checking it's status.

The similar approach is also used by qti/{sc7180,sc7280} platforms
by providing a way to select QTISECLIB_PATH.

This code is providing a generic way how to wire any code
via custom $(CUSTOM_PKG_PATH)/custom_pkg.mk makefile with also an
option to wire custom SMC. SMC functionality depends on "package".

Change-Id: Icedffd582f76f89fc399b0bb2e05cdaee9b743a0
Signed-off-by: Amit Nagal <amit.nagal@amd.com>
diff --git a/plat/xilinx/zynqmp/custom_sip_svc.c b/plat/xilinx/zynqmp/custom_sip_svc.c
new file mode 100644
index 0000000..459aa39
--- /dev/null
+++ b/plat/xilinx/zynqmp/custom_sip_svc.c
@@ -0,0 +1,17 @@
+/*
+ * Copyright (c) 2022-2023, Advanced Micro Devices Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <common/bl_common.h>
+#include <common/debug.h>
+#include <smccc_helpers.h>
+
+uint64_t custom_smc_handler(uint32_t smc_fid, uint64_t x1, uint64_t x2,
+			    uint64_t x3, uint64_t x4, void *cookie,
+			    void *handle, uint64_t flags)
+{
+	WARN("Unimplemented SiP Service Call: 0x%x\n", smc_fid);
+	SMC_RET1(handle, SMC_UNK);
+}
diff --git a/plat/xilinx/zynqmp/include/custom_svc.h b/plat/xilinx/zynqmp/include/custom_svc.h
new file mode 100644
index 0000000..389a7bc
--- /dev/null
+++ b/plat/xilinx/zynqmp/include/custom_svc.h
@@ -0,0 +1,16 @@
+/*
+ * Copyright (c) 2022-2023, Advanced Micro Devices Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+#ifndef CUSTOM_SVC_H
+#define CUSTOM_SVC_H
+
+#define ZYNQMP_SIP_SVC_CUSTOM   U(0x82002000)
+#define ZYNQMP_SIP_SVC64_CUSTOM U(0xC2002000)
+
+uint64_t custom_smc_handler(uint32_t smc_fid, uint64_t x1, uint64_t x2,
+			    uint64_t x3, uint64_t x4, void *cookie,
+			    void *handle, uint64_t flags);
+
+#endif /* CUSTOM_SVC_H */
diff --git a/plat/xilinx/zynqmp/platform.mk b/plat/xilinx/zynqmp/platform.mk
index b751de8..38e7408 100644
--- a/plat/xilinx/zynqmp/platform.mk
+++ b/plat/xilinx/zynqmp/platform.mk
@@ -139,6 +139,12 @@
 BL31_CPPFLAGS		+=	-fno-jump-tables
 TF_CFLAGS_aarch64	+=	-mbranch-protection=none
 
+ifdef CUSTOM_PKG_PATH
+include $(CUSTOM_PKG_PATH)/custom_pkg.mk
+else
+BL31_SOURCES		+=	plat/xilinx/zynqmp/custom_sip_svc.c
+endif
+
 ifneq (${RESET_TO_BL31},1)
   $(error "Using BL31 as the reset vector is only one option supported on ZynqMP. Please set RESET_TO_BL31 to 1.")
 endif
diff --git a/plat/xilinx/zynqmp/sip_svc_setup.c b/plat/xilinx/zynqmp/sip_svc_setup.c
index 4ce9b8a..997cb1e 100644
--- a/plat/xilinx/zynqmp/sip_svc_setup.c
+++ b/plat/xilinx/zynqmp/sip_svc_setup.c
@@ -9,6 +9,7 @@
 #include <common/runtime_svc.h>
 #include <tools_share/uuid.h>
 
+#include <custom_svc.h>
 #include "ipi_mailbox_svc.h"
 #include "pm_svc_main.h"
 
@@ -89,6 +90,11 @@
 	case ZYNQMP_SIP_SVC_VERSION:
 		SMC_RET2(handle, SIP_SVC_VERSION_MAJOR, SIP_SVC_VERSION_MINOR);
 
+	case ZYNQMP_SIP_SVC_CUSTOM:
+	case ZYNQMP_SIP_SVC64_CUSTOM:
+		return custom_smc_handler(smc_fid, x1, x2, x3, x4, cookie,
+					  handle, flags);
+
 	default:
 		WARN("Unimplemented SiP Service Call: 0x%x\n", smc_fid);
 		SMC_RET1(handle, SMC_UNK);