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).