VAR-SOM-AM33 Yocto FIDO GS

VAR-SOM-AM33 Yocto 1.8 (Fido) Distribution User's Guide

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

Installing the kernel to the bootable SD-Card

In order to install the 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

NOTE:
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