VAR-SOM-AM33 Yocto FIDO GS
About this Manual
This document describes how to install Variscite's Yocto release for the VAR-SOM-AM33.
The Yocto distribution provides a fundamental software platform for development, deployment and execution on VAR-SOM-AM33. It abstracts the functionality provided by the hardware.
In this context, the document contains instructions to:
- Install the release on a development machine.
- Build the sources included in this release.
- Instaling the binaries on the VAR-SOM-AM33.
- Booting the VAR-SOM-AM33.
Installation
Prerequisites
Before starting the installation, make sure below system requirements are met:
- Host machine running a Ubuntu 14.04 64 LTS.
- VAR-SOM-AM33 Evaluation Kit + VAR-SOM-AM33 Yocto support installation sources and binaries (from FTP). Please refer to support@variscite.com for obtaining FTP credentials.
The Linux host is used for the following:
- Recompiling U-Boot / kernel.
- Hosting the NFS server to boot the EVM with NFS as root filesystem.
Either of Windows or Linux host can be used for:
- Hosting the TFTP server required for downloading the kernel and file-system images from U-Boot using Ethernet.
- Running a serial console terminal application
Building the Yocto distribution via Bitbake will produce a complete set of downloaded source code + binaries for each component:
- Yocto build environment
- Downloaded Linux kernel source code + build kernel binaries (DTB and zImage) for VAR-SOM-AM33.
- Downloaded U-Boot source code + build U-boot binaries (MLO and U-boot) for VAR-SOM-AM33.
- Linux root file-system.
Install the Arago toolchain
$ wget --no-check-certificate http://releases.linaro.org/15.05/components/toolchain/binaries/arm-linux-gnueabihf/gcc-linaro-4.9-2015.05-x86_64_arm-linux-gnueabihf.tar.xz $ sudo tar -xvf gcc-linaro-4.9-2015.05-x86_64_arm-linux-gnueabihf.tar.xz -C /opt
Install development tools
$ sudo apt-get install git build-essential diffstat texinfo gawk chrpath gcc-multilib wget socat libsdl1.2-dev mtd-utils dos2unix
Download TI's Yocto Fido Distribution
$ mkdir ~/yocto_varsomam33 $ cd ~/yocto_varsomam33 $ git clone git://arago-project.org/git/projects/oe-layersetup.git tisdk
Downloading VAR-SOM-AM33 Support
Download the VAR-SOM-AM33 Yocto support installation from github:
$ mkdir ~/yocto_varsomam33/tisdk/sources $ cd ~/yocto_varsomam33/tisdk/sources $ git clone https://github.com/varigit/meta-variscite-amx3
Downloading the YOCTO Fido 1.8 configuration
Download the YOCTO Fido 1.8 sources as follows:
$ cd ~/yocto_varsomam33/tisdk $ ./oe-layertool-setup.sh -f sources/meta-variscite-amx3/conf/var-som-amx3_sdk-02.00.00-config.txt
local.conf customizations
Edit you local.conf file:
$ cd ~/yocto_varsomam33/tisdk/build $ gedit conf/local.conf
Change your parallel build and download directory:
Parallel build
Set the build parameters to fully utilize your host machine
BB_NUMBER_THREADS = '4'
PARALLEL_MAKE = '-j 6'
BB_NUMBER_THREADS should be your host machine's number of threads minus 2 or same.
PARALLEL_MAKE should be the number of threads your host machine has plus two.
Download directory
Recommended to save download time and space.
DL_DIR = "/home/<uname>/yocto_dl"
Building the VAR-SOM-AM33 Yocto image
First, change directory to the build directory of Yocto:
$ cd ~/yocto_varsomam33/tisdk/build
The developer can build the tisdk-rootfs-image image as follows:
$ export PATH=/opt/gcc-linaro-4.9-2015.05-x86_64_arm-linux-gnueabihf/bin:$PATH $ . conf/setenv $ MACHINE=varsomam33 bitbake tisdk-rootfs-image
After the image was built, all images will be located in: ~/yocto_varsomam33/tisdk/build/arago-tmp-external-linaro-toolchain/deploy/images/ - Specifically:
Build Results
The resulted images are locaated in tmp/deploy/images/var-som-mx6.
| Image Name |
How to use |
|---|---|
| zImage | Kernel uncompressed image |
| zImage-var-som-am33.dtb | The VAR-SOM-AM33 kernel device tree |
| uImage | Linux kernel image, same binary for SD-Card or NAND Flash |
| MLO | The MLO is pre-u-boot SW component, required for DDR initialization |
| u-boot.img | U-Boot bootloader |
| tisdk-rootfs-image-varsomam33.tar.gz | Compressed rootfs tarball |
If the rootfs directory already exists - Please make sure to erase all its content before extracting a new rootfs image into it:
$ sudo rm -rf ~/yocto_varsomam33/rootfs/*
Extract the rootfs as follows:
$ sudo mkdir ~/yocto_varsomam33/rootfs $ sudo tar xvf ./arago-tmp-external-linaro-toolchain/deploy/images/varsomam33/tisdk-rootfs-image-varsomam33.tar.gz -C ~/yocto_varsomam33/rootfs
This creates a rootfs directory for the Yocto / VAR-SOM-AM33 build.
Create a bootable SD-Card
To create a bootable SD-Card image, which includes a UBIFS file-system based recovery image - Please do as follows:
- Insert a 4GB SD-Card to host computer
- Run dmesg command to identify which /dev/sdX was created
- To generate the SD-Card - Run script (and choose the correct /dev/sdX of the 4GB SD-Card inserted):
$ cd ~/yocto_varsomam33/tisdk/sources/meta-variscite-amx3/utils $ sudo ./create-sdcard.sh ~/yocto_varsomam33/tisdk ~/yocto_varsomam33/rootfs/
The above procedure will result in a bootable SD-Card including MLO, U-boot, Kernel and file system + Linux recovery image to flash the NAND based on UBI file-system.
To boot the bootable SD-Card, follow the steps below:
- Insert the SD card into the SD/MMC slot of the custom board
- Press and hold the boot select switch while powering ON the board
- Login as root (no password)
Boot
The Kernel and root the file-system can be booted either from NAND, SD-Card or can be retrieved via ethernet to RAM using TFTP.
Nand Flash root file-system is UBIFS based which is the most recommended filesystem for nand flashes.
Following sections describe various kernel boot options possible.
Boot from MMC/SD
For creating a bootable SD , follow the below instruction on creating a resude SD. http://www.variwiki.com/index.php?title=VAR-SOM-AM33_Arago_GS#NAND_Recovery
To boot the Linux, type:
U-Boot# run mmc_boot
Boot from NAND
By default the VAR-SOM-AM33 boots from NAND.
The SPL, U-Boot, kernel uImage and UBIFS filesystem are flashed on the NAND flash at production.
Flash Images to NAND
Replacing Nand Flash images can be done from either Linux user space or U-Boot.
From U-Boot
U-Boot # mmc rescan
U-Boot # nand erase 0x0 0x280000
U-Boot # mmc rescan
U-Boot # fatload mmc ${mmc_dev} ${loadaddr} MLO
U-Boot # nand write ${loadaddr} 0x0 0x20000
U-Boot # nand write ${loadaddr} 0x20000 0x20000
U-Boot # nand write ${loadaddr} 0x40000 0x20000
U-Boot # fatload mmc ${mmc_dev} ${loadaddr} u-boot.img
U-Boot # nand write ${loadaddr} 0x80000 0x1c0000
U-Boot # fatload mmc ${mmc_dev} ${loadaddr} uImage
U-Boot # nand erase 0x280000 0x500000
U-Boot # nand write ${loadaddr} 0x280000 0x500000
From Linux shell
<< Install SPL >> $ flash_erase /dev/mtd0 0 0 $ flash_erase /dev/mtd1 0 0 $ flash_erase /dev/mtd2 0 0 $ flash_erase /dev/mtd3 0 0 $ nandwrite -p /dev/mtd0 <MLO file> $ nandwrite -p /dev/mtd1 <MLO file> $ nandwrite -p /dev/mtd2 <MLO file> $ nandwrite -p /dev/mtd3 <MLO file> << Install U-Boot >> $ flash_erase /dev/mtd4 0 0 $ flash_erase /dev/mtd5 0 0 $ nandwrite -p /dev/mtd4 <u-boot.img file> << Install Kernel >> $ flash_erase /dev/mtd6 0 0 $ nandwrite -p /dev/mtd6 <uImage file>
NAND Recovery script
Variscite provides NAND-recovery.sh script, as a full example of flashing all required binaries to NAND-Flash.
An already made, prebuilt bootable SD-Card, can be downloaded and mounted on SD-Card from Variscite's FTP, please refer to :
VAR-SOM-AM33 Yocto NAND Recovery
Build U-Boot out of yocto tree
Please refer to : Build u-boot out of yocto tree
Building Linux kernel out-of-yocto tree
For manually building the Linux kernel, out of the yocto build system, please refer to :
Build linux kernel out of yocto tree
Replace bootable SD-Card's kernel
In order to install the newly created kernel to the SD-Card, please follow the instructions below:
1) Plug in the bootable SD-Card created above to a Linux host PC
2) Mount the second partition, which holds the system's file system as /media/rootfs.
3) Install by executing the following commands:
$ sudo cp arch/arm/boot/zImage /media/rootfs/boot $ sudo cp arch/arm/boot/dts/var-som-am33.dtb /media/rootfs/boot $ sudo make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- modules_install INSTALL_MOD_PATH=/media/rootfs $ sync $ sudo umount /media/boot $ sudo umount /media/rootfs $ sudo umount /media/user
Out-of-tree Kernel Modules
Some drivers like the SGX and WLAN drivers are delivered as modules outside of the kernel tree. These drivers binaries are already included in the pre-built root file-systems provided by Variscite.
Support carrier boards without a Touch screen
In order to skip the Touch screen calibration on the first boot on carrier boards without a Touch screen -
Please insert the SD-Card to a Linux machine (or VM) after creating the SD-Card and type the following command to disable touch screen calibration at the first boot:
$ sudo touch /media/boot/ws-calibrate.rules