OpenEmbedded / Angstrom : use the demo root filesystem

Boot to the installed rootfs

Check Load Linux with u-boot chapter in the u-boot page to know how to load a Linux kernel.

Once loaded, the Linux kernel tries to mount a root file system ; command line parameters can indicate a location of such a rootfs. This option can be specified during the build process of through a u-boot environment variable.

Here is a sample command line for booting at the beginning of the NAND FLASH : address 0x0 indicated in the proper Address text field during the flashing process (step #6).

mem=64M console=ttyS0,115200 root=/dev/mtdblock0 rw rootfstype=jffs2

setenv bootargs 'mem=64M console=ttyS0,115200 root=/dev/mtdblock0 rw rootfstype=jffs2'
saveenv

Fit application set to your needs

While building the rootfs image

The AT91 demo policy is to bring the user more application to figure out what the capacities of the CPU are. We add then more packages at build time. The way to add packages to a base Angstrom image at building time is to add a new recipe, stating that it requires the base recipe, and to modify the ANGSTROM_EXTRA_INSTAL variable. Basically this is exactly the same thing as extending the RDEPENDS variable (Cf. angstrom-x11-image.bb recipe) :

RDEPENDS = "\
    [..] 
    ${ANGSTROM_EXTRA_INSTALL}"

Check the attached angstrom-x11-image-demo.bb file that extends the angstrom-x11-image.bb rule in the org.openembedded.dev/packages/angstrom/ directory.

ANGSTROM_EXTRA_INSTALL += " \
    <package_name> \
    <another_package_or_task> \
    <..> \
    "

The complete process of how to build the rootfs is described in the How to build Angstrom for AT91 from sources chapter.

This point is discussed in details in this acticle : The correct way to add packages to an OpenEmbedded Image.

With pre-built packets in hands

Referring to the Angstrom Manual, you can check how to install new packages in an existing Angstrom distribution. 5. Installing Software and Package Management. So, there is always the ability to add applications to an already built distribution.

Here is different mean to add packaged applications to a running system.

Install application packages over the network

Reference chapter in the Angstrom manual.

Here is a detailed page about the ipkg system.

On the target, /etc/ipkg.conf, /etc/ipkg/*.conf files points towards the servers where the device can pull packages from.

Angstrom feeds are discussed in the Angstrom Wiki.

Information on packages are stored on particular files : the Packages or Packages.gz files. You can create a feed on you own, building such a file to describe package content, dependencies and management information. This file is downloaded to the target while issuing the ipkg update command.

You can create a custom ipkg feed using the ipkg-make-index compiled and installed in the staging directory created during the OpenEmbedded/Angstrom build process.

ipkg-make-index . | gzip > Packages.gz

path_to_staging_dir/i686-linux/bin/ipkg-make-index . | gzip > Packages.gz

Procedure

On the host machine :

• construct packages
• collect packages in a directory (done by the OpenEmbedded system : in path_to_deploy_dir/glibc/ipk/armv5te/)
• configure your web server to give access to that directory

On the target

• configure your Ethernet interface
• check that you can access the web server and the feed (package directory)
• run ipkg update
• run ipkg list to see if the package you want is in the "available packages" list
• run ipkg install
• check if the package is installed with the ipkg list_installed command

Install application packages from local storage

You can pick those packages in the deploy/glibc/ipk/ directory once you built them with bitbake.

You can install .ipk packages from all mass-storage support you can connect to a board.

• usb key
• SD/MMC card