The eMMC driver was designed to be linked to the existing MMC/SD block device
driver (mmcblk.c).

* Mini how-to
On the BeagleBone Black, the block device files /dev/c1d* (major = 8) are free.
The driver can use /dev/c1d0.
# service up /service/emmc -dev /dev/c1d0

* Programmed Input/Output
The driver does not have support for DMA.

* High capacity cards
Data address for media =< 2GB is byte address, and data address for media > 2GB
is sector (512B) address. The driver was designed to handle both address modes,
but it was tested on a 2GB card.

* References
BeagleBone Black System Reference Manual, Revision A5.6.
AM335x Sitara Processors Technical Reference Manual. Literature number: SPRUH73L
Embedded MultiMediaCard Product Standard (MMCA, 4.41). Document number: JESD84-A441
AM335x Sitara Processors Datasheet. Literature number: SPRS717F
OMAP35x Applications Processor Technical Reference Manual. Literature number: SPRUF98X
MINIX 3 MMC/SD source code.