environment: distro: Add SF distro command

Add distro boot command support for SPI flash (SF).

This distro boot will read the boot script at specific
location at the flash and start sourcing the same.

This file need to include on required include/config
file.

Cc: Tom Rini <trini@konsulko.com>
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Reviewed-by: Tom Rini <trini@konsulko.com>

include/environment/distro/sf.h

@@ -0,0 +1,41 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (C) 2020 Amarula Solutions(India)
+ *
+ * SF distro configurations.
+ */
+
+#ifndef __DISTRO_SF_CONFIG_H
+#define __DISTRO_SF_CONFIG_H
+
+#if CONFIG_IS_ENABLED(CMD_SF)
+#define BOOTENV_SHARED_SF(devtypel)				\
+	#devtypel "_boot=" 					\
+	"if " #devtypel " probe ${busnum}; then "		\
+		"devtype=" #devtypel "; "	  		\
+		"run scan_sf_for_scripts; "	  		\
+	"fi\0"
+#define BOOTENV_DEV_SF(devtypeu, devtypel, instance) 		\
+	"bootcmd_" #devtypel #instance "=" 			\
+		"busnum=" #instance "; " 			\
+		"run " #devtypel "_boot\0"
+#define BOOTENV_DEV_NAME_SF(devtypeu, devtypel, instance) 	\
+	#devtypel #instance " "
+#else
+#define BOOTENV_SHARED_SF(devtypel)
+#define BOOTENV_DEV_SF \
+	BOOT_TARGET_DEVICES_references_SF_without_CONFIG_CMD_SF
+#define BOOTENV_DEV_NAME_SF \
+	BOOT_TARGET_DEVICES_references_SF_without_CONFIG_CMD_SF
+
+#endif /* CONFIG_CMD_SF */
+
+#define BOOTENV_SF \
+	BOOTENV_SHARED_SF(sf) \
+	"scan_sf_for_scripts="					\
+		"${devtype} read ${scriptaddr} "		\
+			"${script_offset_f} ${script_size_f}; "	\
+		"source ${scriptaddr}; "			\
+		"echo SCRIPT FAILED: continuing...\0"
+
+#endif /* __DISTRO_SF_CONFIG_H */