spl: spl_nor: surround Linux-load code with #ifdef CONFIG_SPL_OS_BOOT

If CONFIG_SPL_NOR_SUPPORT is defined, spl_nor_load_image() requires
spl_start_uboot(), CONFIG_SYS_OS_BASE, CONFIG_SYS_SPL_ARGS_ADDR,
CONFIG_SYS_FDT_BASE to be defined even if users just want to run
U-Boot, not Linux.  This is inconvenient.

This patch is following the codying style of common/spl/spl_nand.c.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>

common/spl/spl_nor.c

@@ -15,37 +15,51 @@ void spl_nor_load_image(void)
 	 */
 	spl_image.flags |= SPL_COPY_PAYLOAD_ONLY;
 
-	if (spl_start_uboot()) {
-		/*
-		 * Load real U-Boot from its location in NOR flash to its
-		 * defined location in SDRAM
-		 */
-		spl_parse_image_header(
-			(const struct image_header *)CONFIG_SYS_UBOOT_BASE);
+#ifdef CONFIG_SPL_OS_BOOT
+	if (!spl_start_uboot()) {
+		struct image_header *header;
 
-		memcpy((void *)spl_image.load_addr,
-		       (void *)(CONFIG_SYS_UBOOT_BASE +
-				sizeof(struct image_header)),
-		       spl_image.size);
-	} else {
 		/*
 		 * Load Linux from its location in NOR flash to its defined
 		 * location in SDRAM
 		 */
-		spl_parse_image_header(
-			(const struct image_header *)CONFIG_SYS_OS_BASE);
+		header = (const struct image_header *)CONFIG_SYS_OS_BASE;
 
-		memcpy((void *)spl_image.load_addr,
-		       (void *)(CONFIG_SYS_OS_BASE +
-				sizeof(struct image_header)),
-		       spl_image.size);
+		if (image_get_os(header) == IH_OS_LINUX) {
+			/* happy - was a Linux */
 
-		/*
-		 * Copy DT blob (fdt) to SDRAM. Passing pointer to flash
-		 * doesn't work (16 KiB should be enough for DT)
-		 */
-		memcpy((void *)CONFIG_SYS_SPL_ARGS_ADDR,
-		       (void *)(CONFIG_SYS_FDT_BASE),
-		       (16 << 10));
+			spl_parse_image_header(header);
+
+			memcpy((void *)spl_image.load_addr,
+			       (void *)(CONFIG_SYS_OS_BASE +
+					sizeof(struct image_header)),
+			       spl_image.size);
+
+			/*
+			 * Copy DT blob (fdt) to SDRAM. Passing pointer to
+			 * flash doesn't work (16 KiB should be enough for DT)
+			 */
+			memcpy((void *)CONFIG_SYS_SPL_ARGS_ADDR,
+			       (void *)(CONFIG_SYS_FDT_BASE),
+			       (16 << 10));
+
+			return;
+		} else {
+			puts("The Expected Linux image was not found.\n"
+			     "Please check your NOR configuration.\n"
+			     "Trying to start u-boot now...\n");
+		}
 	}
+#endif
+
+	/*
+	 * Load real U-Boot from its location in NOR flash to its
+	 * defined location in SDRAM
+	 */
+	spl_parse_image_header(
+			(const struct image_header *)CONFIG_SYS_UBOOT_BASE);
+
+	memcpy((void *)spl_image.load_addr,
+	       (void *)(CONFIG_SYS_UBOOT_BASE + sizeof(struct image_header)),
+	       spl_image.size);
 }