arm: socfpga: mailbox: Notify SDM on HPS code execution stages

Introducing a new mailbox command "HPS_STAGE_NOTIFY" to notify Secure
Device Manager (SDM) on the stage of HPS code execution.

Generally, there are three main code execution stages: First Stage Boot
Loader (FSBL) which is U-Boot SPL, Second Stage Boot Loader (SSBL) which
is U-Boot, and the Operating System (OS) which is Linux.

This enables the user to query the SDM for HPS error details.

Signed-off-by: Alif Zakuan Yuslaimi <alif.zakuan.yuslaimi@altera.com>
Reviewed-by: Tien Fong Chee <tien.fong.chee@altera.com>
diff --git a/arch/arm/mach-socfpga/mailbox_s10.c b/arch/arm/mach-socfpga/mailbox_s10.c
index b69bd3e..f9c34e8 100644
--- a/arch/arm/mach-socfpga/mailbox_s10.c
+++ b/arch/arm/mach-socfpga/mailbox_s10.c
@@ -6,6 +6,7 @@
 
 #include <asm/arch/clock_manager.h>
 #include <asm/arch/mailbox_s10.h>
+#include <asm/arch/smc_api.h>
 #include <asm/arch/system_manager.h>
 #include <asm/global_data.h>
 #include <asm/io.h>
@@ -474,6 +475,17 @@
 					  urgent, resp_buf_len, resp_buf);
 }
 
+int mbox_hps_stage_notify(u32 execution_stage)
+{
+#if !defined(CONFIG_SPL_BUILD) && defined(CONFIG_SPL_ATF)
+	return smc_send_mailbox(MBOX_HPS_STAGE_NOTIFY, 1, &execution_stage,
+				0, 0, NULL);
+#else
+	return mbox_send_cmd(MBOX_ID_UBOOT, MBOX_HPS_STAGE_NOTIFY,
+			     MBOX_CMD_DIRECT, 1, &execution_stage, 0, 0, NULL);
+#endif
+}
+
 int mbox_send_cmd_only(u8 id, u32 cmd, u8 is_indirect, u32 len, u32 *arg)
 {
 	return mbox_send_cmd_only_common(id, cmd, is_indirect, len, arg);