BBB: Add "mmc" command that interfaces to the onboard eMMC

[Jarielle Catbagan]

I just want to add that I was able to transfer the uMon image from the
SD card to the eMMC.  I then removed the SD card and power-cycled the
BBB, and I was able to boot uMon from the eMMC.

The sequence steps I took are as follows:

        sd init
        mmc init
        sd read 0x80100000 0 102
        mmc write 0x80100000 0 102

The '102' is the number of 512 byte blocks required to transfer the uMon image.

On Tue, Aug 4, 2015 at 11:03 AM, Jarielle Catbagan
<jcatbagan93 at gmail.com> wrote:
> These series of patches add the "mmc" command which is the interface to the onboard eMMC on the BBB.
> The "mmc" command is implemented with initialization, reading, and writing functionality.
>
> Furthermore, the MMC0 and MMC1 clock enable are moved to initCPUio() in cpuio.c to ensure that the
> MMC modules are enabled before they are accessed.
>