[U-Boot] [PATCH 1/2] image: Implement IH_TYPE_KERNEL_NOLOAD

[Stephen Warren]

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 at nvidia.com>
---
This is a third attempt to support ARM Linux zImage's ability to run from
anywhere in RAM.

This patch actually ended up being much smaller (patch file size) than
previous attempts. Both my previous attempts could probably be rewritten
to adjust the image load address in the same way as this patch and hence
also be just as small; I don't recommend using any of my previous patches
wthout rework because of this.

before this patch:

   text    data     bss     dec     hex filename
 166642    3568  217020  387230   5e89e ./u-boot

with this patch:

   text    data     bss     dec     hex filename
 166761    3568  217020  387349   5e915 ./u-boot

Is this small enough to do without a config option? I certainly hope so,
because ifdefing every one of these tiny code changes would look ugly.

Tested on NVIDIA Tegra Seaboard:

*  Legacy uImage containing a kernel (and appended DT), of type
IH_TYPE_KERNEL.

*  Legacy uImage containing a kernel (and appended DT), of type
IH_TYPE_KERNEL_NOLOAD.

*  Legacy uImage containing a kernel, of type IH_TYPE_KERNEL_NOLOAD,
plus a separate plain FDT (no uImage wrapping).

*  Legacy uImage containing a kernel, of type IH_TYPE_KERNEL_NOLOAD,
plus a uImage-wrapped initrd, plus a separate plain FDT (no uImage
wrapping).

* FIT image containing both kernel of type IH_TYPE_KERNEL_NOLOAD
and FDT.

* FIT image containing just a kernel of type IH_TYPE_KERNEL_NOLOAD,
plus a separate plain FDT (no FIT/legacy uImage wrapping).

 common/cmd_bootm.c    |   10 +++++++++-
 common/image.c        |    1 +
 include/image.h       |    1 +
 tools/default_image.c |    3 ++-
 4 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/common/cmd_bootm.c b/common/cmd_bootm.c
index d301332..1d62c99 100644
--- a/common/cmd_bootm.c
+++ b/common/cmd_bootm.c
@@ -271,7 +271,13 @@ 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 */
@@ -795,7 +801,8 @@ 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;
@@ -873,6 +880,7 @@ 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;
diff --git a/common/image.c b/common/image.c
index 555d9d9..aacae5a 100644
--- a/common/image.c
+++ b/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",	},
diff --git a/include/image.h b/include/image.h
index c56a18d..f01eb92 100644
--- a/include/image.h
+++ b/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
diff --git a/tools/default_image.c b/tools/default_image.c
index 6ea3b46..e9d0729 100644
--- a/tools/default_image.c
+++ b/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;
-- 
1.7.0.4