arm: socfpga: Export board ID as U-Boot environment

Board ID is exported as environment variable for use to boot Linux with FIT
configuration.

Signed-off-by: Alif Zakuan Yuslaimi <alif.zakuan.yuslaimi@altera.com>
Signed-off-by: Tien Fong Chee <tien.fong.chee@altera.com>
Reviewed-by: Tien Fong Chee <tien.fong.chee@altera.com>
diff --git a/arch/arm/mach-socfpga/board.c b/arch/arm/mach-socfpga/board.c
index 24a15f7..d07b3fc 100644
--- a/arch/arm/mach-socfpga/board.c
+++ b/arch/arm/mach-socfpga/board.c
@@ -6,6 +6,7 @@
  */
 
 #include <config.h>
+#include <asm/arch/board.h>
 #include <asm/arch/clock_manager.h>
 #include <asm/arch/mailbox_s10.h>
 #include <asm/arch/misc.h>
diff --git a/arch/arm/mach-socfpga/include/mach/board.h b/arch/arm/mach-socfpga/include/mach/board.h
new file mode 100644
index 0000000..2c3127e
--- /dev/null
+++ b/arch/arm/mach-socfpga/include/mach/board.h
@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (C) 2025 Altera Corporation <www.altera.com>
+ */
+
+#ifndef BOARD_H_
+#define BOARD_H_
+
+u8 socfpga_get_board_id(void);
+
+#endif /* _BOARD_H_ */
diff --git a/arch/arm/mach-socfpga/misc_soc64.c b/arch/arm/mach-socfpga/misc_soc64.c
index 573a8f7..793b8b8 100644
--- a/arch/arm/mach-socfpga/misc_soc64.c
+++ b/arch/arm/mach-socfpga/misc_soc64.c
@@ -6,6 +6,7 @@
  */
 
 #include <altera.h>
+#include <asm/arch/board.h>
 #include <asm/arch/mailbox_s10.h>
 #include <asm/arch/misc.h>
 #include <asm/arch/reset_manager.h>
@@ -57,10 +58,15 @@
 int arch_misc_init(void)
 {
 	char qspi_string[13];
+	unsigned long id;
 
 	sprintf(qspi_string, "<0x%08x>", cm_get_qspi_controller_clk_hz());
 	env_set("qspi_clock", qspi_string);
 
+	/* Export board_id as environment variable */
+	id = socfpga_get_board_id();
+	env_set_ulong("board_id", id);
+
 	return 0;
 }
 #endif