diff --git a/realm/realm_payload_main.c b/realm/realm_payload_main.c
new file mode 100644
index 0000000..bd4dec7
--- /dev/null
+++ b/realm/realm_payload_main.c
@@ -0,0 +1,85 @@
+/*
+ * Copyright (c) 2022, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ */
+
+#include <stdio.h>
+
+#include <debug.h>
+#include <host_realm_helper.h>
+#include <host_shared_data.h>
+#include "realm_def.h"
+#include <realm_rsi.h>
+#include <tftf_lib.h>
+
+/*
+ * This function reads sleep time in ms from shared buffer and spins PE in a loop
+ * for that time period.
+ */
+static void realm_sleep_cmd(void)
+{
+	uint64_t sleep = realm_shared_data_get_host_val(HOST_SLEEP_INDEX);
+
+	INFO("REALM_PAYLOAD: Realm payload going to sleep for %llums\n", sleep);
+	waitms(sleep);
+}
+
+/*
+ * This function requests RSI/ABI version from RMM.
+ */
+static void realm_get_rsi_version(void)
+{
+	u_register_t version;
+
+	version = rsi_get_version();
+	if (version == (u_register_t)SMC_UNKNOWN) {
+		ERROR("SMC_RSI_ABI_VERSION failed (%ld)", (long)version);
+		return;
+	}
+
+	INFO("RSI ABI version %u.%u (expected: %u.%u)",
+	RSI_ABI_VERSION_GET_MAJOR(version),
+	RSI_ABI_VERSION_GET_MINOR(version),
+	RSI_ABI_VERSION_GET_MAJOR(RSI_ABI_VERSION),
+	RSI_ABI_VERSION_GET_MINOR(RSI_ABI_VERSION));
+}
+
+/*
+ * This is the entry function for Realm payload, it first requests the shared buffer
+ * IPA address from Host using HOST_CALL/RSI, it reads the command to be executed,
+ * performs the request, and returns to Host with the execution state SUCCESS/FAILED
+ *
+ * Host in NS world requests Realm to execute certain operations using command
+ * depending on the test case the Host wants to perform.
+ */
+void realm_payload_main(void)
+{
+	uint8_t cmd = 0U;
+	bool test_succeed = false;
+
+	realm_set_shared_structure((host_shared_data_t *)rsi_get_ns_buffer());
+	if (realm_get_shared_structure() != NULL) {
+		cmd = realm_shared_data_get_realm_cmd();
+		switch (cmd) {
+		case REALM_SLEEP_CMD:
+			realm_sleep_cmd();
+			test_succeed = true;
+			break;
+		case REALM_GET_RSI_VERSION:
+			realm_get_rsi_version();
+			test_succeed = true;
+			break;
+		default:
+			INFO("REALM_PAYLOAD: %s invalid cmd=%hhu", __func__, cmd);
+			break;
+		}
+	}
+
+	if (test_succeed) {
+		rsi_exit_to_host(HOST_CALL_EXIT_SUCCESS_CMD);
+	} else {
+		rsi_exit_to_host(HOST_CALL_EXIT_FAILED_CMD);
+	}
+}