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Eric Lee
version 1.0a, 8/19/2014
This document describes how Embedian builds a customized version of TI’s am335x AMSDK 7.0 release for Embedian's SMARC T335X product platform. The approach is to pull from Embedian's public facing GIT repository and build that using bitbake. The reason why we use this approach is that it allows co-development. The build output is comprised of binary images, feed packages, and an SDK for SMARC T335X specific development.
TI makes their AMSDK Arago build scripts available via the following GIT repository:
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It is this repository that actually pulls in the oe-layersetup project to perform the Linux AMSDK builds for TI’s entire suite of ARM CortextA chips. In this document we are only concerned with the oe-layersetup project.
The supplied meta-embedian-sdk7 Yocto compliant layer has the following organization:
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Notes on meta-embedian-sdk7 layer content
conf/machine/*
This folder contains the machine definitions for the smarct335x platform and backup repository in Embedian. These select the associated kernel, kernel config, u-boot, u-boot config, and UBI image settings.
recipes-bsp/u-boot/*
This folder contains recipes used to build DAS U-boot for smarct335x platform.
recipes-connectivity/lftp/*
This folder adds lftp ftp client utility for smarct335x platform.
recipes-core/base-files/*
This recipe is used to amend the device hostname for the platform.
recipes-core/busybox/*
This recipe modifies TI’s BusyBox configuration to remove telnet from the image.
recipes-core/images/*
These recipes are used to create the final target images for the devices. When you run Bitbake one of these recipes would be specified. For example, to build the root file system for the smarct335x platform:
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recipes-core/init-ifupdown*
This recipe is used to amend device network interfaces
recipes-devtools/nodejs/*
These recipes build the Node.js Javascript server execution environment.
recipes-kernel/linux/*
Contains the recipes needed to build the smarct335x Linux kernels.
recipes-multimedia/amsdk-av-files/*
This recipe is to add smarct335x compatible machine for the platform.
recipes-multimedia/x264/*
This original commit history has been rewritten.
recipes-support/boost/*
Adds Boost to the images. Boost provides various C++ libraries that encourage cross-platform development.
recipes-support/ntp/*
Network time protocol support.
recipes-tisdk/ti-tisdk-makefile/*
Add smarct335x device tree into Makefile.
To build the latest TI am335x 7.0 AMSDK you first need an Unbuntu Linux 12.04LTS or Ubuntu 14.04LTS installation (preferably 32bit). Since bitbake does not accept building images using root privileges, please do not login as a root user when performing the instructions in this section.
Once you have Ubuntu 12.04 LTS or Ubuntu 14.04LTS running, install the additional required support packages using the following console command:
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If you are using a 64-bit Linux, then you'd also need to install 32-bit support libraries, needed by the pre-built Linaro toolchain and other binary tools.
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You’ll also need to change the default shell to bash from Ubuntu’s default dash shell (select the <No> option):
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To build TI’s am335x SDK you will need to install the Linaro arm compiler that TI used for the release:
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PATH
definition to the .bashrc
file in your $HOME
directory:
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$ wget -c http://developer.embedian.com/download/attachments/8847362/fix-binutils-textinfo-ubuntu14.04.patch ~/ |
meta-embedian-sdk7
layer to the build process.
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# This template file was created by taking the oe-core/meta/conf/bblayers.conf # file and removing the BBLAYERS section at the end.
# LAYER_CONF_VERSION is increased each time build/conf/bblayers.conf # changes incompatibly LCONF_VERSION = "5"
BBPATH = "${TOPDIR}" BBFILES ?= ""
# Layers configured by oe-core-setup script BBLAYERS += " \ /home/oeeric/oe-layersetup-sdk7/sources/meta-embedian-sdk7 \ |
If your platform is SMARC T3354 (with sgx features), you can simply add "sgx" in the MACHINE_FEATURES to have the powervr driver loaded by editing the ~/oe-layersetup-sdk7/source/meta-embedian/conf/machine/smarct335x.conf file. Find MACHINE_FEATURES and add "sgx" in the very bottom: |
MACHINE_FEATURES = "kernel26 alsa usbgadget usbhost apm vfat ext2 screen touchscreen ethernet sgx" |
Please do not enable the sgx MACHINE FEATURES if your platform is SMARC T3352.
To build the Embedian SMARC T335X and am335x-evm developer board images, respectively, use the following commands:
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The first clean build might take more than 10 hours. If you met errors during the building process, let it finish and usually build again should be fine. |
Once it done, you can find all required images under ~/oe-layersetup-sdk7/build/arago-tmp-external-linaro-toolchain/deploy/images/
You may want to build programs that aren’t installed into a root file system so you can make them available via a feed site (described below.) To do this you can build the package directly and then build the package named package-index to add the new package to the feed site.
The following example builds the minicom program and makes it available on the feed site:
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~/oe-layersetup-sdk7/build/arago-tmp-external-linaro-toolchain/deploy
.deploy/images/*
This folder contains the binary images for the root file system and the Embedian SMARCT335X specific version of the am335x SDK. Specifically the images are:
deploy/images/u-boot.img
This u-boot bootloader binary for SMARC T335X
deploy/images/MLO
The "Stage 1 Boot Loader" for SMARC T335X. Its purpose is load the Stage 2 Boot Loader (u-boot.img).
deploy/images/zImage
The kernel zImage for SMARC T335X.
deploy/images/zImage-am335x-smarct335x.dtb
The device tree binary file for SMARC T335X.
deploy/images/smarct335x-rootfs-image-smarct335x*
Embedian root file system images for software development on Embedian’s SMARC T335X platforms.
deploy/images/smarct335x-amsdk-image*
These files contain the entire TI AMSDK augmented with Boost and other options to simplify Embedian SMARC T335X software development.
deploy/images/arago-base-tisdk-image-smarct335x*
These images are used to create the SMARC T335X AMSDK (see smarct335x-amsdk-image-smarct335x*
).
deploy/images/tisdk-rootfs-image-am335x-evm*
TI Arago root file system images for software development on TI’s am335x-evm and BeagleBone platforms.
deploy/ipk/*
This folder contains all the packages used to construct the root file system images. They are in opkg format (similar format to Debian packages) and can be dynamically installed on the target plaform via a properly constructed feed file. Here is an example of the feed file (named arago-smarct335x-feed.conf) that is used internally at Embedian to install upgrades onto a smarct335x platform without reflashing the file system:
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deploy/licenses/*
deploy/sdk/arago-2013.12-cortexa8-linux-gnueabi-tisdk.sh
For these instruction, we are assuming: DISK=/dev/mmcblk0, "lsblk" is very useful for determining the device id.
$ export DISK=/dev/mmcblk0 |
Erase SD card:
$ |
Create Partition Layout:
$ sudo sfdisk --in-order --Linux --unit M ${DISK} <<-__EOF__ 1 , 48 , 0xE ,* ,,,- __EOF__ |
Format Partitions:
for : DISK=/dev/mmcblk0 $ sudo mkfs.vfat -F 16 ${DISK}p1 -n boot $ sudo mkfs.ext4 ${DISK}p2 -L rootfs for : DISK=/dev/sdX $ sudo mkfs.vfat -F 16 ${DISK} 1 -n boot $ sudo mkfs.ext4 ${DISK} 2 -L rootfs |
Mount Partitions:
On some systems, these partitions may be auto-mounted...
$ sudo mkdir -p /media/boot/dtbs $ sudo mkdir -p /media/rootfs/ for : DISK=/dev/mmcblk0 $ sudo mount ${DISK}p1 /media/boot/ $ sudo mount ${DISK}p2 /media/rootfs/ for : DISK=/dev/sdX $ sudo mount ${DISK} 1 /media/boot/ $ sudo mount ${DISK} 2 /media/rootfs/ |
Copy MLO/u-boot.img to the boot partition
$ sudo cp -v MLO /media/boot/ $ sudo cp -v u-boot.img /media/boot/ |
Create "uEnv.txt" boot script: (vim uEnv.txt)
For 3.12.y or after :
optargs="consoleblank=0 mem=512M" loadaddr=0x82000000 initrd_high=0xffffffff loadimage=load mmc ${mmcdev}:${mmcpart} ${loadaddr} ${kernel_file} ##Un-comment to enable systemd in Debian Wheezy console=ttyO3,115200n8 mmcargs=setenv bootargs console=${console} root=${mmcroot} rootfstype=${mmcrootfstype} ${optargs} #zImage: #zImage + uInitrd: where uInitrd has to be generated on the running system. ###Begin Rootfs from NFS ###Begin Load kernel from TFTP |
Copy uEnv.txt to the boot partition:
$ sudo cp -v ./uEnv.txt /media/boot/ |
Copy zImage to the boot partition:
$ sudo cp -v zImage /media/boot |
Copy device tree binary to /media/boot/dtbs (Note: the file name in /media/boot/dtbs/ has to be am335x-smarct335x.dtb)
$ sudo cp -v zImage-am335x-smarct335x.dtb /media/boot/dtbs/am335x-smarct335x.dtb |
Arago:
$ sudo tar xvfz smarct335x-rootfs-image-smarct335x.tar.gz -C /media/rootfs |
Note:
Kernel modules are included in root file systems.
The following procedure can be used on a Embedian SMARC T335X device to download and utilize the feed file show above to install the minicom terminal emulation program:
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In order to package your application and include it in the root filesystem image, you must write a BitBake recipe for it.
When starting from scratch, it is easiest to learn by example from existing recipes.
For software that uses autotools (./configure; make; make install), writing recipes can be very simple:
DESCRIPTION = "Hello World Recipe using autotools" HOMEPAGE = "http://www.embedian.com/" SECTION = "console/utils" PRIORITY = "optional" LICENSE = "GPL" PR = "r0" SRC_URI = "git://git@git.embedian.com/developer/helloworld-autotools.git;protocol=ssh;tag=v1.0" S = "${WORKDIR}/git" inherit autotools |
SRC_URI
specifies the location to download the source from. It can take the form of any standard URL using http://, ftp://, etc. It can also fetch from SCM systems, such as git in the example above.
PR
is the package revision variable. Any time a recipe is updated that should require the package to be rebuilt, this variable should be incremented.
inherit autotools
brings in support for the package to be built using autotools, and thus no other instructions on how to compile and install the software are needed unless something needs to be customized.
S
is the source directory variable. This specifies where the source code will exist after it is fetched from SRC_URI and unpacked. The default value is ${WORKDIR}/${PN}-${PV}
, where PN
is the package name and PV
is the package version. Both PN
and PV
are set by default using the filename of the recipe, where the filename has the format PN_PV.bb
.
This example shows a simple case of building a helloworld.c file directly using the default compiler (gcc). Since it isn’t using autotools or make, we have to tell BitBake how to build it explicitly.
DESCRIPTION = "HelloWorld" SECTION = "examples" LICENSE = "GPL" SRC_URI = "file://helloworld.c" S = "${WORKDIR}" do_compile() { ${CC} ${CFLAGS} ${LDFLAGS} helloworld.c -o helloworld } do_install() { install -d ${D}${bindir} install -m 0755 helloworld ${D}${bindir} } |
In this case, SRC_URI
specifies a file that must exist locally with the recipe. Since there is no code to download and unpack, we set S
to WORKDIR
since that is where helloworld.c will be copied to before it is built.
WORKDIR
is located at ${OETREE}/build/arago-tmp-external-linaro-toolchain/work/armv7ahf-vfp-neon-3.8-oe-linux-gnueabi/<package name and version>
for most packages. If the package is machine-specific (rather than generic for the armv7ahf architecture), it may be located in the smarct335x-oe-linux-gnueabi subdirectory depending on your hardware (this applies to kernel packages, images, etc).
do_compile
defines how to compile the source. In this case, we just call gcc directly. If it isn’t defined, do_compile
runs make
in the source directory by default.
do_install
defines how to install the application. This example runs install
to create a bin directory where the application will be copied to and then copies the application there with permissions set to 755.
D
is the destination directory where the application is installed to before it is packaged.
${bindir}
is the directory where most binary applications are installed, typically /usr/bin
.
For a more in-depth explanation of BitBake recipes, syntax, and variables, see the Recipe Chapter of the OpenEmbedded User Manual.
version 1.0a, 8/19/2014
Last updated 2014-08-19