Documentation/Omap4-eMMC-Android.txt

How to flash eMMC for booting Android on OMAP4 platform
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A 32GB eMMC device is connected to MMC2 controller on OMAP4 platform.This README
document describes the procedure to flash eMMC for booting android on OMAP4.

On Omap4 SDP MMC1 is connected to a card cage on the board and MMC2 is connected
to a eMMC device.This procedure assumes that an external SD card capable of booting
android on omap4 is used to boot for the first time and then the below procedure is
fallowed to flash eMMC.

In order to make this procedure simpler a copy of eMMC boot image is provided.This can
be downloaded from the below link.Please copy this to the first partition of the
external SD card which will be later copied to the eMMC.

Link:
https://gforge.ti.com/gf/download/frsrelease/271/3438/Omap4_eMMC_Bootimg

To start with boot the omap4 using the external SD card.At the android kernel prompt
execute the below command to tranfer the eMMC image(that was downloaded from the above
link and kept in the SD card first partition) to eMMC device.

dd if=/sdcard/Omap4_eMMC_Bootimg of=/dev/block/mmcblk1

This would flash the x-loader and u-boot to eMMC(raw space at the begining of the card)
and also create two partitions on the eMMC device.The first partition begins after the
raw space.The first partition is used to flash a linux kernel image and the second
partition is used for the file system.

Further,the usb based android gadget is used to mount the eMMC device onto the host PC
in order to transfer the kernel and the android file system. In order to do that execute
the below line from the command prompt.

echo /dev/block/mmcblk1  >/sys/devices/platform/musb_hdrc/gadget/lun0/file

Connect a linux host PC to OMAP4 using a USB cable.

The eMMC will be recognized as /dev/<sd*> on the host PC.

Use the mkfs.vfat and mkfs.ext3 to format the first and second partitions.

For e.g run the below from host PC.

mkfs.vfat /dev/sd<b1>
mkfs.ext3 /dev/sd<b2>

Now unplug-plug the usb cable to omap4.This should auto mount the partitions on PC.

Copy kernel Image to first partition.
cp uImage /media/disk-1/ <assuming that eMMC first partition is mounted as disk-1 on PC>

Copy the android FS to the second partition.
cp my-android/* /media/disk-2/ <assuming that eMMC second partition is mounted as disk-2 on PC>

Set up the sysboot switch settings on the SDP to boot from MMC2 and reset the power to the board.
The bootloader should boot up from eMMC and load the kernel from the FAT partition of the
eMMC device and boot the same.The env is set by default to load the FS from the eMMC second partition.

Limitation:
The external MMC/SD card should be maintained in the cage during kernel boot in
order for the kernel to recognize MMC1 and MMC2 in the order.The external SD card
can then be unpluged after kernel boot to load media content.