芯片用的是AM3352，在uboot中可以识别板载emmc，但是进入内核后无法识别，打印信息如下
[ 2.145859] clock: disabling unused clocks to save power [ 2.157817] Detected MACID=ec:11:27:cf:69:89 [ 2.164518] cpsw: Detected MACID = ec:11:27:cf:69:8b [ 2.177536] input: gpio-keys as /devices/platform/gpio-keys/input/input1 [ 2.186170] drivers/rtc/hctosys.c: unable to open rtc device (rtc0) [ 2.193573] Waiting for root device /dev/mmcblk0p2... [ 2.249808] mmc0: host does not support reading read-only switch. assuming write-enable. [ 2.264256] mmc0: new high speed SDHC card at address aaaa [ 2.271335] mmcblk0: mmc0:aaaa SC16G 14.8 GiB [ 2.282765] mmcblk0: p1 p2 [ 2.365717] kjournald starting. Commit interval 5 seconds [ 2.375739] EXT3-fs (mmcblk0p2): using internal journal [ 2.381299] EXT3-fs (mmcblk0p2): recovery complete [ 2.390321] EXT3-fs (mmcblk0p2): mounted filesystem with ordered data mode [ 2.397762] VFS: Mounted root (ext3 filesystem) on device 179:2. [ 2.408939] devtmpfs: mounted [ 2.413376] Freeing init memory: 388K
只能识别用于启动的SD卡，无法识别emmc
