diff --git a/plat/xilinx/zynqmp/pm_service/pm_svc_main.c b/plat/xilinx/zynqmp/pm_service/pm_svc_main.c
index d88e5fa..e664df8 100644
--- a/plat/xilinx/zynqmp/pm_service/pm_svc_main.c
+++ b/plat/xilinx/zynqmp/pm_service/pm_svc_main.c
@@ -255,7 +255,7 @@
  * function with rt_svc_handle signature
  */
 uint64_t pm_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)
+			uint64_t x4, const void *cookie, void *handle, uint64_t flags)
 {
 	enum pm_ret_status ret;
 	uint32_t payload[PAYLOAD_ARG_CNT];
@@ -575,7 +575,7 @@
  * function with rt_svc_handle signature
  */
 uint64_t em_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)
+			uint64_t x4, const void *cookie, void *handle, uint64_t flags)
 {
 	enum pm_ret_status ret;
 
diff --git a/plat/xilinx/zynqmp/pm_service/pm_svc_main.h b/plat/xilinx/zynqmp/pm_service/pm_svc_main.h
index abadd40..9cff3cb 100644
--- a/plat/xilinx/zynqmp/pm_service/pm_svc_main.h
+++ b/plat/xilinx/zynqmp/pm_service/pm_svc_main.h
@@ -11,10 +11,10 @@
 
 int pm_setup(void);
 uint64_t pm_smc_handler(uint32_t smc_fid, uint64_t x1, uint64_t x2, uint64_t x3,
-			uint64_t x4, void *cookie, void *handle,
+			uint64_t x4, const void *cookie, void *handle,
 			uint64_t flags);
 
 uint64_t em_smc_handler(uint32_t smc_fid, uint64_t x1, uint64_t x2, uint64_t x3,
-			uint64_t x4, void *cookie, void *handle,
+			uint64_t x4, const void *cookie, void *handle,
 			uint64_t flags);
 #endif /* PM_SVC_MAIN_H */