[U-Boot] Board-specific commands unintentionally linked into SPL?

[Tyler Olmstead]

Hi all,

I have encountered some issues adding a board-specific command to the
board file of a project I have been working on. Specifically, after
adding a U-Boot shell command to my board file, I have been seeing
link-stage failures when attempting to build SPL.

<snip>

UNDEF_SYM=`arm-arago-linux-gnueabi-objdump -x
/home/tolmstead/tolmstead_lab-OptiPlex-380/uboot/uboot_nand/spl/arch/arm/cpu/arm926ejs/davinci/libdavinci.o
/home/tolmstead/tolmstead_lab-OptiPlex-380/uboot/uboot_nand/spl/arch/arm/cpu/arm926ejs/libarm926ejs.o
/home/tolmstead/tolmstead_lab-OptiPlex-380/uboot/uboot_nand/spl/arch/arm/lib/libarm.o
/home/tolmstead/tolmstead_lab-OptiPlex-380/uboot/uboot_nand/spl/board/davinci/da8xxevm/libda8xxevm.o
/home/tolmstead/tolmstead_lab-OptiPlex-380/uboot/uboot_nand/spl/drivers/mtd/nand/libnand.o
/home/tolmstead/tolmstead_lab-OptiPlex-380/uboot/uboot_nand/spl/drivers/serial/libserial.o
/home/tolmstead/tolmstead_lab-OptiPlex-380/uboot/uboot_nand/spl/lib/libgeneric.o
| sed  -n -e 's/.*\(__u_boot_cmd_.*\)/-u\1/p'|sort|uniq`; cd
/home/tolmstead/tolmstead_lab-OptiPlex-380/uboot/uboot_nand/spl/ &&
arm-arago-linux-gnueabi-ld  -T
/home/tolmstead/tolmstead_lab-OptiPlex-380/uboot/uboot_nand/spl/u-boot-spl.lds
--gc-sections -Bstatic -Ttext 0xc1080000 $UNDEF_SYM
arch/arm/cpu/arm926ejs/start.o --start-group
arch/arm/cpu/arm926ejs/davinci/libdavinci.o
arch/arm/cpu/arm926ejs/libarm926ejs.o arch/arm/lib/libarm.o
board/davinci/da8xxevm/libda8xxevm.o drivers/mtd/nand/libnand.o
drivers/serial/libserial.o lib/libgeneric.o --end-group
/home/tolmstead/tolmstead_lab-OptiPlex-380/uboot/uboot_nand/spl/arch/arm/lib/eabi_compat.o
-L /usr/local/ti-sdk-am180x-evm/linux-devkit/bin/../lib/gcc/arm-arago-linux-gnueabi/4.3.3
-lgcc -Map u-boot-spl.map -o u-boot-spl
board/davinci/da8xxevm/libda8xxevm.o: In function `do_mycmd':
/home/tolmstead/tolmstead_lab-OptiPlex-380/uboot/uboot_nand/board/davinci/da8xxevm/awpb3.c:121:
undefined reference to `eth_get_dev_by_index'
/home/tolmstead/tolmstead_lab-OptiPlex-380/uboot/uboot_nand/board/davinci/da8xxevm/awpb3.c:123:
undefined reference to `eth_write_hwaddr'
/home/tolmstead/tolmstead_lab-OptiPlex-380/uboot/uboot_nand/board/davinci/da8xxevm/awpb3.c:126:
undefined reference to `printf'
make[1]: *** [/home/tolmstead/tolmstead_lab-OptiPlex-380/uboot/uboot_nand/spl/u-boot-spl]
Error 1
make[1]: Leaving directory
`/home/tolmstead/tolmstead_lab-OptiPlex-380/uboot/uboot_nand/spl'
make: *** [spl/u-boot-spl.bin] Error 2

</snip>

In the output above, one can see the environment variable $UNDEF_SYM
being defined as the result of the following SPL makefile
(spl/Makefile) target:

GEN_UBOOT = \
	UNDEF_SYM=`$(OBJDUMP) -x $(LIBS) | \
	sed  -n -e 's/.*\($(SYM_PREFIX)__u_boot_cmd_.*\)/-u\1/p'|sort|uniq`;\
	cd $(obj) && $(LD) $(LDFLAGS) $(LDFLAGS_$(@F)) $$UNDEF_SYM $(__START) \
		--start-group $(__LIBS) --end-group $(PLATFORM_LIBS) \
		-Map u-boot-spl.map -o u-boot-spl

$(obj)u-boot-spl:	depend $(START) $(LIBS) $(obj)u-boot-spl.lds
	$(GEN_UBOOT)

For my target, $UNDEF_SYM expands to the following:
-u__u_boot_cmd_mycmd

As I understand it, this is to force the inclusion of the commands
into the command table located in the special .u_boot_cmd section so
that unreferenced commands are not linked out of the final U-Boot
binary. However, I don't think that the inclusion of commands into the
SPL is intended. Removing the $UNDEF_SYM variable from the SPL
makefile resolves my build issues. I am planning on submitting a
patch. Does anyone see a flaw in my thinking?

Thanks,
-- Tyler