[U-Boot] Question about board-specific Makefile actions

[James Chargin <jimccrown@gmail.com>]

I have a custom board in a git workspace for U-Boot 2014.07. I've copied 
most of this from the .../board/ti/beagle. My board directory Makefile 
looks like

8<---
obj-y := board.o
8<---

I'd like to add a few files to this directory that are processed during 
"make all" and have any newly derived files deleted during "make clean".

I've experimented with various Makefile contents but I can't get the new 
files processed or any newly derived files deleted. U-Boot's makefile 
system is quite large for my experience level and it seems I don't have 
enough understanding.

A new file might contain some hush commands that are to be executed from 
the U-Boot command line. I'd like to use "source" to process these 
commands. The "source" command requires that its argument be an image (I 
get this into memory via TFTP), so I'd like "make all" to transform the 
text file containing the hush commands into the image file. I'd also 
like "make clean" to delete the derived image file.

So, if my hush commands are in a text file called test.txt, I'd like 
"make all" to apply mkimage so that a test.img is generated. I'd also 
like "make clean" to delete test.img.

I tried various changes to my Makefile, but the most likely seeming 
changes are

8<---
IMG  = test.img

obj-y	:= board.o

board.o : $(IMG)

%.img : %.txt
	$(srctree)/tools/mkimage -T script -n $* -C none -d $< $@

CLEAN_FILES += $(IMG)
CLEAN_DIRS  += .
8<---

This doesn't work, nor has any other approach I've taken. mkimage is 
never run for "make all" and test.img doesn't get deleted if I create a 
fake one and run "make clean"

Could someone offer a solution, either directly, or by pointing at an 
existing board that does something similar?

Thanks
Jim

-- 
Jim Chargin
AJA Video Systems                       jimc@aja.com
(530) 271-3334                          http://www.aja.com