Difference between revisions of "Boot from MMC"
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Revision as of 22:22, 31 March 2009
This section describes how to boot off an MMC/microSD memory card. At the moment it is not possible to boot from microSDHC cards, usually the ones with more than 2GB capacity. This is because the high-speed drivers are not supported. See this thread
Contents
Partition the card
Place the card into your reader, and unmount it if it is mounted.
Assuming it is the only mmc card, run fdisk:
sudo fdisk /dev/mmcblk0
Delete any partitions on the disk, in this case there were two:
Command (m for help): d Partition number (1-4): 1 Command (m for help): d Selected partition 2
Create the kernel partition:
Command (m for help): n Partition number (1-4): 1 Command (m for help): n Selected partition 2
Set it to FAT16 file system:
Command (m for help): t Selected partition 1 Hex code (type L to list codes): 6 Changed system type of partition 1 to 6 (FAT16)
Create the root fs partition:
Command (m for help): n Command action e extended p primary partition (1-4) p Partition number (1-4): 2 First cylinder (22-984, default 22): 22 Last cylinder, +cylinders or +size{K,M,G} (22-984, default 984): 984
Save the partition table:
Command (m for help): w The partition table has been altered! Calling ioctl() to re-read partition table. WARNING: If you have created or modified any DOS 6.x partitions, please see the fdisk manual page for additional information. Syncing disks.
Format the card
Format the kernel partition
mkfs.vfat -F 16 /dev/mmcblk0p1 -n gum-uimage
Format the rootfs partition
mkfs.ext2 /dev/mmcblk0p2 -L gum-rootfs
Remove and reinsert the card, you should have two mmc drives, one called gum-uimage and one called gum-rootfs
Enable booting from MMC in kernel
If you don't have the user.collection directory setup to change the appropriate conf file, do so like:
mkdir -p $USERBRANCH cp -r $GUMSTIXBRANCH/conf $USERBRANCH
Edit the conf file for your gumstix, eg for the verdex the file is:
$GUMSTIXTOP/user.collection/conf/machine/gumstix-custom-verdex.conf
Uncomment the line:
MACHINE_FEATURES += "mmcroot"
The kernel will now build with the necessary drivers
Save the file and rebuild the image:
bitbake -c rebuild task-base-gumstix bitbake -c rebuild gumstix-kernel bitbake -c rebuild gumstix-basic-image
Put the images on the card
Copy the uimage file from the working directory to the uimage partition on the card, eg:
cp $GUMSTIXTOP/tmp/deploy/glibc/images/gumstix-custom-verdex/uImage-2.6.21-r1-gumstix-custom-verdex.bin /media/gum-uimage/uimage
Make sure the file on the card is named uimage
Copy the gumstix-factory.script to the uimage partition as well:
cp $GUMSTIXTOP/extras/mmc-root/gumstix-factory.script /media/gum-uimage
Unpack the root file system to the rootfs partition on the card, eg:
sudo tar -xvpzf $GUMSTIXTOP/tmp/deploy/glibc/images/gumstix-custom-verdex/Angstrom-gumstix-basic-image-glibc-ipk-2007.9-test-20090212-gumstix-custom-verdex.rootfs.tar.gz -C /media/gum-rootfs/
Unmount BOTH partitions.
Boot!
Place the card in the gumstix and power up.
You should see comething similar to:
U-Boot 1.2.0 (May 10 2008 - 21:22:03) - PXA270@600 MHz - 1604 *** Welcome to Gumstix *** DRAM: 128 MB Flash: 32 MB Using default environment Hit any key to stop autoboot: 0 Instruction Cache is ON Found gumstix-factory.script on MMC... ## Executing script at a2000000 Booting from mmc/microSD... Detected: 1985024 blocks of 1024 bytes (1938MB) SD card. Vendor: Man 03 OEM SD "SU02G" Date 06/2008 Product: 1091675832 Revision: 8.0 reading uimage
followed by the rest of the boot process.