[U-Boot] confused about set/test of EMMC_BOOT-related config settings

[Tom Rini]

On Wed, Aug 21, 2013 at 11:25:43AM -0400, Robert P. J. Day wrote:
> 
>   perusing cmd_mmc.c, ran across test for CONFIG_SUPPORT_EMMC_BOOT
> with which i was unfamiliar so i did a grep to see where it was having
> an effect and got this:
> 
> $ grep -r EMMC_BOOT *
> arch/arm/cpu/armv7/exynos/spl_boot.c:#ifdef CONFIG_SUPPORT_EMMC_BOOT
> arch/arm/cpu/armv7/exynos/spl_boot.c:#ifdef CONFIG_SUPPORT_EMMC_BOOT
> boards.cfg:am335x_boneblack             arm         armv7       am335x              ti             am33xx      am335x_evm:SERIAL1,CONS_INDEX=1,EMMC_BOOT
> common/cmd_mmc.c:#ifdef CONFIG_SUPPORT_EMMC_BOOT
> common/cmd_mmc.c:#ifdef CONFIG_SUPPORT_EMMC_BOOT
> common/cmd_mmc.c:#endif /* CONFIG_SUPPORT_EMMC_BOOT */
> common/cmd_mmc.c:#ifdef CONFIG_SUPPORT_EMMC_BOOT
> drivers/mmc/mmc.c:#ifdef CONFIG_SUPPORT_EMMC_BOOT
> include/configs/am335x_evm.h:#elif defined(CONFIG_EMMC_BOOT)
> include/configs/exynos5250-dt.h:#define CONFIG_SUPPORT_EMMC_BOOT
> $
> 
>   confused because in the midst of all that, i see a reference in
> am335x_evm.h to CONFIG_EMMC_BOOT rather than CONFIG_SUPPORT_EMMC_BOOT.
> is that deliberate? i haven't dug further to see what that option
> represents, but that difference just looks odd. thoughts?

For am335x CONFIG_EMMC_BOOT is like CONFIG_SPI_BOOT, CONFIG_NOR_BOOT,
etc, of making an otherwise generic config support booting (and assuming
env is on) a particular medium.  CONFIG_SUPPORT_EMMC_BOOT is I believe
about supporting additional features of the eMMC "boot" partitions which
I believe either aren't enforced on the beaglebone black (nor omap5
uEVM) or aren't in the driver (I forget what I figured out a while ago
playing with the kernel as well).

-- 
Tom
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