omap-common/spl: Add linux boot to SPL

This adds Linux booting to the SPL

This depends on CONFIG_MACH_TYPE patch by Igor Grinberg
(http://article.gmane.org/gmane.comp.boot-loaders.u-boot/105809)

Related CONFIGs:
CONFIG_SPL_OS_BOOT
	Activates/Deactivates the OS booting feature
CONFIG_SPL_OS_BOOT_KEY
	defines the IO-pin number u-boot switch - if pressed u-boot is
	booted
CONFIG_SYS_NAND_SPL_KERNEL_OFFS
	Offset in NAND of direct boot kernel image to use in SPL
CONFIG_SYS_SPL_ARGS_ADDR
	Address where the kernel boot arguments are expected - this is
	normaly RAM-begin + 0x100

Signed-off-by: Simon Schwarz <simonschwarzcor@gmail.com>
CC: Tom Rini <tom.rini@gmail.com>
CC: Stefano Babic <sbabic@denx.de>
CC: Wolfgang Denk <wd@denx.de>

arch/arm/cpu/armv7/omap-common/spl.c

@@ -65,6 +65,25 @@ void board_init_f(ulong dummy)
 	relocate_code(CONFIG_SPL_STACK, &gdata, CONFIG_SPL_TEXT_BASE);
 }
 
+/*
+ * Default function to determine if u-boot or the OS should
+ * be started. This implementation always returns 1.
+ *
+ * Please implement your own board specific funcion to do this.
+ *
+ * RETURN
+ * 0 to not start u-boot
+ * positive if u-boot should start
+ */
+#ifdef CONFIG_SPL_OS_BOOT
+__weak int spl_start_uboot(void)
+{
+	printf("SPL: Please implement spl_start_uboot() for your board\n");
+	printf("SPL: Direct Linux boot not active!\n");
+	return 1;
+}
+#endif
+
 void spl_parse_image_header(const struct image_header *header)
 {
 	u32 header_size = sizeof(struct image_header);
@@ -92,6 +111,24 @@ void spl_parse_image_header(const struct image_header *header)
 	}
 }
 
+/*
+ * This function jumps to an image with argument. Normally an FDT or ATAGS
+ * image.
+ * arg: Pointer to paramter image in RAM
+ */
+#ifdef CONFIG_SPL_OS_BOOT
+static void __noreturn jump_to_image_linux(void *arg)
+{
+	debug("Entering kernel arg pointer: 0x%p\n", arg);
+	typedef void (*image_entry_arg_t)(int, int, void *)
+		__attribute__ ((noreturn));
+	image_entry_arg_t image_entry =
+		(image_entry_arg_t) spl_image.entry_point;
+	/* cleanup_before_linux(); */ /*write SPL function for that*/
+	image_entry(0, CONFIG_MACH_TYPE, arg);
+}
+#endif
+
 static void __noreturn jump_to_image_no_args(void)
 {
 	typedef void __noreturn (*image_entry_noargs_t)(u32 *);
@@ -149,6 +186,13 @@ void board_init_r(gd_t *id, ulong dummy)
 		debug("Jumping to U-Boot\n");
 		jump_to_image_no_args();
 		break;
+#ifdef CONFIG_SPL_OS_BOOT
+	case IH_OS_LINUX:
+		debug("Jumping to Linux\n");
+		spl_board_prepare_for_linux();
+		jump_to_image_linux((void *)CONFIG_SYS_SPL_ARGS_ADDR);
+		break;
+#endif
 	default:
 		puts("Unsupported OS image.. Jumping nevertheless..\n");
 		jump_to_image_no_args();

arch/arm/cpu/armv7/omap-common/spl_nand.c

@@ -29,7 +29,6 @@
 #include <version.h>
 #include <asm/omap_common.h>
 
-
 void spl_nand_load_image(void)
 {
 	struct image_header *header;
@@ -50,7 +49,7 @@ void spl_nand_load_image(void)
 	/*use CONFIG_SYS_TEXT_BASE as temporary storage area */
 	header = (struct image_header *)(CONFIG_SYS_TEXT_BASE);
 #ifdef CONFIG_SPL_OS_BOOT
-	if (!spl_uboot_key()) {
+	if (!spl_start_uboot()) {
 		/*
 		 * load parameter image
 		 * load to temp position since nand_spl_load_image reads
@@ -74,31 +73,39 @@ void spl_nand_load_image(void)
 		nand_spl_load_image(CONFIG_SYS_NAND_SPL_KERNEL_OFFS,
 			CONFIG_SYS_NAND_PAGE_SIZE, (void *)header);
 		spl_parse_image_header(header);
-		nand_spl_load_image(CONFIG_SYS_NAND_SPL_KERNEL_OFFS,
-			spl_image.size, (void *)spl_image.load_addr);
-	} else
+		if (header->ih_os == IH_OS_LINUX) {
+			/* happy - was a linux */
+			nand_spl_load_image(CONFIG_SYS_NAND_SPL_KERNEL_OFFS,
+				spl_image.size, (void *)spl_image.load_addr);
+			nand_deselect();
+			return;
+		} else {
+			printf("The Expected Linux image was not"
+				"found. Please check your NAND"
+				"configuration.\n");
+			printf("Trying to start u-boot now...\n");
+		}
+	}
 #endif
-	{
 #ifdef CONFIG_NAND_ENV_DST
-		nand_spl_load_image(CONFIG_ENV_OFFSET,
-			CONFIG_SYS_NAND_PAGE_SIZE, (void *)header);
-		spl_parse_image_header(header);
-		nand_spl_load_image(CONFIG_ENV_OFFSET, spl_image.size,
-			(void *)spl_image.load_addr);
+	nand_spl_load_image(CONFIG_ENV_OFFSET,
+		CONFIG_SYS_NAND_PAGE_SIZE, (void *)header);
+	spl_parse_image_header(header);
+	nand_spl_load_image(CONFIG_ENV_OFFSET, spl_image.size,
+		(void *)spl_image.load_addr);
 #ifdef CONFIG_ENV_OFFSET_REDUND
-		nand_spl_load_image(CONFIG_ENV_OFFSET_REDUND,
-			CONFIG_SYS_NAND_PAGE_SIZE, (void *)header);
-		spl_parse_image_header(header);
-		nand_spl_load_image(CONFIG_ENV_OFFSET_REDUND, spl_image.size,
-			(void *)spl_image.load_addr);
+	nand_spl_load_image(CONFIG_ENV_OFFSET_REDUND,
+		CONFIG_SYS_NAND_PAGE_SIZE, (void *)header);
+	spl_parse_image_header(header);
+	nand_spl_load_image(CONFIG_ENV_OFFSET_REDUND, spl_image.size,
+		(void *)spl_image.load_addr);
 #endif
 #endif
-		/* Load u-boot */
-		nand_spl_load_image(CONFIG_SYS_NAND_U_BOOT_OFFS,
-			CONFIG_SYS_NAND_PAGE_SIZE, (void *)header);
-		spl_parse_image_header(header);
-		nand_spl_load_image(CONFIG_SYS_NAND_U_BOOT_OFFS,
-			spl_image.size, (void *)spl_image.load_addr);
-	}
+	/* Load u-boot */
+	nand_spl_load_image(CONFIG_SYS_NAND_U_BOOT_OFFS,
+		CONFIG_SYS_NAND_PAGE_SIZE, (void *)header);
+	spl_parse_image_header(header);
+	nand_spl_load_image(CONFIG_SYS_NAND_U_BOOT_OFFS,
+		spl_image.size, (void *)spl_image.load_addr);
 	nand_deselect();
 }

arch/arm/include/asm/omap_common.h

@@ -93,6 +93,7 @@ u32 omap_boot_mode(void);
 void spl_parse_image_header(const struct image_header *header);
 void omap_rev_string(void);
 void spl_board_prepare_for_linux(void);
+int spl_start_uboot(void);
 
 /* NAND SPL functions */
 void spl_nand_load_image(void);