image: Implement IH_TYPE_KERNEL_NOLOAD

The legacy uImage format includes an absolute load and entry-point
address. When bootm operates on a kernel uImage in memory that isn't
loaded at the address in the image's load address, U-Boot will copy
the image to its address in the header.

Some kernel images can actually be loaded and used at any arbitrary
address. An example is an ARM Linux kernel zImage file. To represent
this capability, IH_TYPE_KERNEL_NOLOAD is implemented, which operates
just like IH_TYPE_KERNEL, except that the load address header is
ignored, and U-Boot does not copy the image to its load address, but
rather uses it in-place.

This is useful when sharing a single (uImage-wrapped) zImage across
multiple boards with different memory layouts; in this case, a specific
load address need not be picked when creating the uImage, but instead
is selected by the board-specific U-Boot environment used to load and
boot that image.

v2: Rename from IH_TYPE_KERNEL_ANYLOAD to IH_TYPE_KERNEL_NOLOAD.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Stefan Roese <sr@denx.de>

common/cmd_bootm.c

@@ -272,7 +272,13 @@ static int bootm_start(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]
 		return 1;
 	}
 
+	if (images.os.type == IH_TYPE_KERNEL_NOLOAD) {
+		images.os.load = images.os.image_start;
+		images.ep += images.os.load;
+	}
+
 	if (((images.os.type == IH_TYPE_KERNEL) ||
+	     (images.os.type == IH_TYPE_KERNEL_NOLOAD) ||
 	     (images.os.type == IH_TYPE_MULTI)) &&
 	    (images.os.os == IH_OS_LINUX)) {
 		/* find ramdisk */
@@ -796,7 +802,8 @@ static int fit_check_kernel(const void *fit, int os_noffset, int verify)
 	}
 
 	show_boot_progress(106);
-	if (!fit_image_check_type(fit, os_noffset, IH_TYPE_KERNEL)) {
+	if (!fit_image_check_type(fit, os_noffset, IH_TYPE_KERNEL) &&
+	    !fit_image_check_type(fit, os_noffset, IH_TYPE_KERNEL_NOLOAD)) {
 		puts("Not a kernel image\n");
 		show_boot_progress(-106);
 		return 0;
@@ -874,6 +881,7 @@ static void *boot_get_kernel(cmd_tbl_t *cmdtp, int flag, int argc,
 		/* get os_data and os_len */
 		switch (image_get_type(hdr)) {
 		case IH_TYPE_KERNEL:
+		case IH_TYPE_KERNEL_NOLOAD:
 			*os_data = image_get_data(hdr);
 			*os_len = image_get_data_size(hdr);
 			break;

common/image.c

@@ -136,6 +136,7 @@ static const table_entry_t uimage_type[] = {
 	{	IH_TYPE_FIRMWARE,   "firmware",	  "Firmware",		},
 	{	IH_TYPE_FLATDT,     "flat_dt",    "Flat Device Tree",	},
 	{	IH_TYPE_KERNEL,	    "kernel",	  "Kernel Image",	},
+	{	IH_TYPE_KERNEL_NOLOAD, "kernel_noload",  "Kernel Image (no loading done)", },
 	{	IH_TYPE_KWBIMAGE,   "kwbimage",   "Kirkwood Boot Image",},
 	{	IH_TYPE_IMXIMAGE,   "imximage",   "Freescale i.MX Boot Image",},
 	{	IH_TYPE_INVALID,    NULL,	  "Invalid Image",	},

include/image.h

@@ -162,6 +162,7 @@
 #define IH_TYPE_UBLIMAGE	11	/* Davinci UBL Image		*/
 #define IH_TYPE_OMAPIMAGE	12	/* TI OMAP Config Header Image	*/
 #define IH_TYPE_AISIMAGE	13	/* TI Davinci AIS Image		*/
+#define IH_TYPE_KERNEL_NOLOAD	14	/* OS Kernel Image, can run from any load address */
 
 /*
  * Compression Types

tools/default_image.c

@@ -35,7 +35,8 @@ static image_header_t header;
 
 static int image_check_image_types(uint8_t type)
 {
-	if ((type > IH_TYPE_INVALID) && (type < IH_TYPE_FLATDT))
+	if (((type > IH_TYPE_INVALID) && (type < IH_TYPE_FLATDT)) ||
+	    (type == IH_TYPE_KERNEL_NOLOAD))
 		return EXIT_SUCCESS;
 	else
 		return EXIT_FAILURE;