[PATCH 2/2] Makefile: add target to produce a SPL compatible uImage

[Jan Luebbe]

This is mostly useful during the initial port of barebox to a new
board which is supported by u-boot. It also allows starting barebox
from a SRAM-based u-boot SPL.

A different load address can be set like this:
make barebox.uimage UIMAGE_BASE=0x80000000

This patch was developed together with Sascha Hauer. Thanks!

Signed-off-by: Jan Luebbe <jlu at pengutronix.de>
---
 Makefile |   16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/Makefile b/Makefile
index 0f1a319..9381e77 100644
--- a/Makefile
+++ b/Makefile
@@ -686,6 +686,22 @@ ifndef CONFIG_PBL_IMAGE
 	$(call cmd,check_file_size,$(CONFIG_BAREBOX_MAX_IMAGE_SIZE))
 endif
 
+# By default the uImage load address is 2MB below CONFIG_TEXT_BASE,
+# leaving space for the compressed PBL image at 1MB below CONFIG_TEXT_BASE.
+UIMAGE_BASE ?= $(shell printf "0x%08x" $$(($(CONFIG_TEXT_BASE) - 0x200000)))
+
+# For development provide a target which makes barebox loadable by an
+# unmodified u-boot
+quiet_cmd_barebox_mkimage = MKIMAGE $@
+      cmd_barebox_mkimage = $(srctree)/scripts/mkimage -A $(ARCH) -T firmware -C none \
+       -O barebox -a $(UIMAGE_BASE) -e $(UIMAGE_BASE) \
+       -n "barebox $(KERNELRELEASE)" -d $< $@
+
+# barebox.uimage is build from the raw barebox binary, without any other
+# headers.
+barebox.uimage: $(KBUILD_BINARY) FORCE
+	$(call if_changed,barebox_mkimage)
+
 ifdef CONFIG_X86
 barebox.S: barebox
 ifdef CONFIG_X86_HDBOOT
-- 
1.7.10.4