[U-Boot] [U-boot] mmc write|read howto

Josh Wu
2013-04-27T06:25:02Z

Hi, Jagan

On 4/27/2013 4:51 AM, Jagan Teki wrote:
> Hi All,
>
> I need some help regarding mmc write and mmc read commands usage.
>
> I am using a 4GB SD/MMC plus and socked eMMC cards, usually I am
> formatting these cards on my host pc with
> fat partition and copy the images into card. while in the u-boot level
> I am reading the images from card and copy it onto mem addr
> like fatload mmc 0 0x1000 uImage.
>
> Can we write the images onto these cards in u-boot level?, using mmc write.
> same way can we read back using mmc read? if so how to do that.

yes, define the CONFIG_FAT_WRITE macro in your board config file.
re-build your u-boot. then you will find "fatwrite" command.

U-Boot> fatwrite
fatwrite - write file into a dos filesystem

Usage:
fatwrite <interface> <dev[:part]> <addr> <filename> <bytes>
- write file 'filename' from the address 'addr' in RAM
to 'dev' on 'interface'

so you can use:
fatwrite mmc 0 0x20000000 file 0x4000

Best Regards,
Josh Wu

>
> Request for help.
>
> Thanks,
> Jagan.
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