u-boot中mmc命令使用

u-boot中mmc命令使用

[u-boot: v2013.01]

[Author: Bo Shen <voice.shen@gmail.com>]

mmc命令的帮助信息如下：

U-Boot> mmc

mmc - MMC sub system   Usage: mmc read addr blk# cnt mmc write addr blk# cnt mmc erase blk# cnt mmc rescan mmc part - lists available partition on current mmc device mmc dev [dev] [part] - show or set current mmc device [partition] mmc list - lists available devices

当系统启动后，系统会将mci0设置为当前设备。使用mmcinfo就可以看到插入到mmc controller 0的sdcard信息。

U-Boot> mmcinfo

Device: mci Manufacturer ID: 3 OEM: 5344 Name: SD04G Tran Speed: 25000000 Rd Block Len: 512 SD version 2.0 High Capacity: Yes Capacity: 3.8 GiB Bus Width: 4-bit   如果SoC支持多个mmc controller并且使能，使用mmc list来查看使能了几个， 可以通过mmc dev来查看当前是那个设备，或者通过mmc dev <NO.>来切换。 像我的系统支持两个mmc controller. U-Boot> mmc list (显示有几个mmc controller) mci 0 mci 1 U-Boot> mmc dev (显示当前是那个device) mmc1 is current device U-Boot> mmc dev 0 (设置0为当前设备) mmc0 is current device   如果，换sdcard，则使用mmc rescan来重新获取sdcard信息 U-Boot> mmc rescan (重新scan当前设备) mci: setting clock 257812 Hz, block size 512 mci: setting clock 22000000 Hz, block size 512 mci: setting clock 257812 Hz, block size 512 gen_atmel_mci: CMDR 00001048 ( 8) ARGR 000001aa (SR: 0c100025) Command Failed mci: setting clock 257812 Hz, block size 512 mci: setting clock 22000000 Hz, block size 512 U-Boot> mmcinfo (列出当前设备的信息) Device: mci Manufacturer ID: 1 OEM: 5041 Name: SK512 Tran Speed: 25000000 Rd Block Len: 512 SD version 1.10 High Capacity: No Capacity: 472.5 MiB Bus Width: 4-bit