SD卡的这一块的硬件线路应该没问题，测量过了。用两张SD卡启动都有类似问题，请大神帮忙分析原因
U-Boot SPL 2015.07-00080-g4523775-dirty (Jan 13 2017 - 14:21:34)
[apm trace]319 :common/spl/spl.c:preloader_console_init
DRA752 ES1.1
[apm trace]118 :arch/arm/cpu/armv7/omap-common/boot-common.c:spl_board_init
[apm trace]198 :common/spl/spl.c:board_init_r
U-Boot SPL 2015.07-00080-g4523775-dirty (Dec 20 2016 - 13:11:26)
DRA752 ES1.1
MMC Device 0 not found
spl: mmc device not found
### ERROR ### Please RESET the board ###
