Thursday, July 16, 2015

Creating a custom Linux BSP for an ARM Cortex-A9 SBC with Yocto 1.8 - Part III

 


In part III of this guide, the installation of the final image to the SD card will be covered.  The SD card will then be booted on the target.  Finally, audio recording and playback will be tested.
Part III of this guide consists of the following sections.

  1. Write the GNU/Linux BSP image to an SD card.
  2. Set the physical switches on the RioTboard (Internet of Things) to boot from the uSD or SD card.
  3. Connect the target to the necessary peripherals for boot.
  4. Test audio recording, audio playback, and Internet connectivity.


1.  Write the GNU/Linux BSP image to an SD card

At this point, the build should be complete, without errors.  The output should be as follows.


 real 254m28.335s
user 737m9.307s
sys 133m39.529s

Insert an SD card into an SD card reader, connect it to the host, and execute the following commands on the host.


 host]$ cd $HOME/src/fsl-community-bsp/build /tmp/deploy/images/imx6dl-riotboard
host]$ sudo umount /dev/sd<X>
host]$ sudo dd if=bsec-image-imx6dl-riotboard.sdcard of=/dev/sd<X> bs=1M
host]$ sudo sync


2. Set the physical switches on the RioTboard to boot from the uSD or SD card.


For booting from the SD card on the bottom of the target, set the physical switches as follows.
SD (J6, bottom) 1 0 1 0 0 1 0 1

For booting from the uSD card on the top of the target, set the physical switches as follows.
uSD (J7, top) 1 0 1 0 0 1 1 0

3. Connect the target to the necessary peripherals for boot.

There are two options

Option 1

Connect one end of an ethernet cable to the target. Connect the other end of the ethernet cable to a hub or DHCP server.  

Connect the board to the host computer via the J18 serial UART pins on the target.  This will require a serial to USB breakout cable.  Connect TX, RX, and GND to RX, TX, and GND on the cable. The cable must have an FTDI or similar level shifter chip. Connect the USB end of the cable to the host computer.

Connect the speakers to the light green 3.5 mm audio out jack and the microphone to the pink 3.5 mm MIC In jack.

Connect a 5V / 4 AMP DC power source to the target.

Run minicom on the host computer. Configure minicom at 115200 8N1 with no hardware flow control and no software flow control. If a USB to serial cable with an FTDI chip in it is used, then the cable should show up in /dev as ttyUSB0 in which case, set the serial device in minicom to /dev/ttyUSB0.

If this option was chosen, drop into U-boot after power on by pressing Enter on the host keyboard with minicom open and connected.

If enter is not pressed after power-on, the target will boot and a login prompt will appear.

A login prompt will not appear.

Option 2

Connect one end of an ethernet cable to the target. Connect the other end of the ethernet cable to a hub or DHCP server.  

Connect a USB keyboard, USB mouse, and monitor (via an HDMI cable) to the target.

Connect the speakers to the light green 3.5 mm audio out jack and the microphone to the pink 3.5 mm MIC In jack.

Connect a 5V / 4 AMP DC power source to the target.

A login prompt will now appear.

4. Test audio recording, audio playback, and Internet connectivity


Type root to log in to the target. The root password is not set.

Execute the following commands on the target

 root@imx6dl-riotboard: alsamixer 

Press F6.
Press arrow down so that 0 imx6-riotboard-sgtl5000 is highlighted.
Press Enter.
Increase Headphone level to 79<>79.
Increase PCM level to 75<>75.
Press Tab.
Increase Mic level to 59.
Increase Capture to 80<>80.
Press Esc.

 root@imx6dl-riotboard: cd /usr/share/alsa/sounds
root@imx6dl-riotboard: aplay *.wav

A sound should be played through the speakers.

 root@imx6dl-riotboard: cd /tmp
root@imx6dl-riotboard: arecord -d 10 micintest.wav

Talk into the microphone for ten seconds.

 root@imx6dl-riotboard: aplay micintest.wav

A recording should play through the speakers.

 root@imx6dl-riotboard: ping riotboard.org

An ICMP reply should be received.

Wednesday, July 15, 2015

Creating a custom Linux BSP for an ARM Cortex-A9 SBC with Yocto 1.8 - Part II

In the second part of this guide, the source code will be pulled, the build configuration will be customized, and the build will be executed.  Part II of this guide consists of the following sections.

  1. Pull the Freescale community BSP platform source code from github. 
  2. Setup the build environment using the predefined imx6dl-riotboard RioTboard (Internet of Things) machine.
  3. Create a new layer for the custom Linux distribution.
  4. Customize the image in the meta-bsec layer. 
  5. Create layer.conf file in the meta-bsec layer. 
  6. Create the distribution configuration file in the meta-bsec layer. 
  7. Add the new layer to bblayers.conf.
  8. Customize the local configuration.
  9. Execute
    the build.

1. Pull the Freescale community BSP platform source code from github.


Execute the following commands on the host.
 host]$ mkdir $HOME/bin  
host]$ curl https://storage.googleapis.com/git-repo-downloads/repo > ~/bin/repo
host]$ chmod a+x $HOME/bin/repo
host]$ echo "PATH=$PATH:$HOME/bin" >> $HOME/.bashrc
host]$ source .bashrc
host]$ mkdir -p $HOME/src/fsl-community-bsp
host]$ cd $HOME/src/fsl-community-bsp
host]$ repo init -u https://github.com/Freescale/fsl-community-bsp-platform -b fido
host]$ repo sync

2. Setup the build environment using the predefined imx6dl-riotboard machine.


Execute the following commands on the host.

 host]$ MACHINE=imx6dl-riotboard . ./setup-environment build  

3. Create a new layer for the custom Linux distribution


Execute the following commands on the host.

 host]$ cd $HOME/src/fsl-community-bsp/sources  
host]$ mkdir -p meta-bsec/conf/distro
host]$ mkdir -p meta-bsec/recipes-bsec/images
host]$ cd poky/meta/recipes-extended/images
host]$ cp core-image-full-cmdline.bb \
../../../../meta-bsec/recipes-bsec/images/bsec-image.bb

4. Customize the image in the meta-bsec layer.


Execute the following commands on the host.

  host]$ cd $HOME/src/fsl-community-bsp/sources/meta-bsec/recipes-bsec/images

Customize bsec-image.bb as follows.  Lines with bold text indicate lines to add to the file.

 DESCRIPTION = "A console-only image with more full-featured Linux system \
functionality installed."

# customize IMAGE_FEATURES as follows
IMAGE_FEATURES += "dev-pkgs tools-sdk tools-debug tools-profile tools-testapps \
debug-tweaks splash ssh-server-openssh package-management"

# packagegroup-core-tools-profile will build and install tracing and profiling tools to the target image.
# packagegroup-core-buildessential will build and install autotools, gcc, etc. to the target image.
# kernel-modules for install of the kernel modules.
# kernel-devsrc for building out of tree modules.
# IMAGE_ROOTFS_EXTRA_SPACE_append for adding extra space to the target rootfs image.

# customize IMAGE_INSTALL as follows
IMAGE_INSTALL = "\
packagegroup-core-boot \
packagegroup-core-full-cmdline \
packagegroup-core-tools-profile \
packagegroup-core-buildessential \
kernel-modules \
${CORE_IMAGE_EXTRA_INSTALL} \
kernel-devsrc \
"
inherit core-image

# Add extra space to the rootfs image
IMAGE_ROOTFS_EXTRA_SPACE_append += "+ 3000000"

5. Create layer.conf file in the meta-bsec layer.


Create sources/meta-bsec/conf/layer.conf with the below contents.

BBPATH .= ":${LAYERDIR}"  
BBFILES += "${LAYERDIR}/recipes-*/*/*.bb \
${LAYERDIR}/recipes-*/*/*.bbappend"
BBFILE_COLLECTIONS += "bsec"
BBFILE_PATTERN_bsec = "^${LAYERDIR}/"
BBFILE_PRIORITY_bsec = "6"


6. Create the distribution configuration file in the meta-bsec layer.


Create sources/meta-bsec/conf/disro/bsecdist.conf with the below contents.

 require conf/distro/poky.conf    
# distro name
DISTRO = "bsecdist"
DISTRO_NAME = "bsecdist distribution"
DISTRO_VERSION = "1.0"
DISTRO_CODENAME = "bsc"
DISTRO_FEATURES_append = " alsa usbhost usbgadget keyboard bluetooth"
SDK_VENDOR = "-bsecdistsdk"
SDK_VERSION := "${@'${DISTRO_VERSION}'.replace('snapshot-${DATE}','snapshot')}"
MAINTAINER = "bsecdist "
INHERIT += "buildhistory"
BUILDHISTORY_COMMIT = "1"

7. Add the new layer to bblayers.conf


Execute the following commands on the host.

 host]$ cd $HOME/src/fsl-community-bsp/build/conf

Customize bblayers.conf by adding the meta-bsec layer to BBLAYERS as follows.

 LCONF_VERSION = "6"

BBPATH = "${TOPDIR}"
BSPDIR := "${@os.path.abspath(os.path.dirname(d.getVar('FILE', True)) + '/../..')}"

BBFILES ?= ""
BBLAYERS = " \
${BSPDIR}/sources/poky/meta \
${BSPDIR}/sources/poky/meta-yocto \
\
${BSPDIR}/sources/meta-openembedded/meta-oe \
${BSPDIR}/sources/meta-openembedded/meta-multimedia \
\
${BSPDIR}/sources/meta-fsl-arm \
${BSPDIR}/sources/meta-fsl-arm-extra \
${BSPDIR}/sources/meta-fsl-demos \
${BSPDIR}/sources/meta-bsec \
"

8. Customize the local configuration


Customize local.conf as follows.

 MACHINE ??= 'imx6dl-riotboard'
# set distro name
DISTRO ?= 'bsecdist'
PACKAGE_CLASSES ?= "package_rpm package_deb"
EXTRA_IMAGE_FEATURES = " "
USER_CLASSES ?= "buildstats image-mklibs image-prelink"
PATCHRESOLVE = "noop"
BB_DISKMON_DIRS = "\
STOPTASKS,${TMPDIR},1G,100K \
STOPTASKS,${DL_DIR},1G,100K \
STOPTASKS,${SSTATE_DIR},1G,100K \
ABORT,${TMPDIR},100M,1K \
ABORT,${DL_DIR},100M,1K \
ABORT,${SSTATE_DIR},100M,1K"
PACKAGECONFIG_append_pn-qemu-native = " sdl"
PACKAGECONFIG_append_pn-nativesdk-qemu = " sdl"
ASSUME_PROVIDED += "libsdl-native"
CONF_VERSION = "1"
BB_NUMBER_THREADS = '4'
PARALLEL_MAKE = '-j 4'
DL_DIR ?= "${BSPDIR}/downloads/"
ACCEPT_FSL_EULA = "1"
# archive source code for all of the packages that will be built into the image
INHERIT += "archiver"
ARCHIVER_MODE[src] = "original"
# ensure that license files accompany each binary in final image
COPY_LIC_MANIFEST = "1"
COPY_LIC_DIRS = "1"
# setup source mirror
# make sure that bitbake checks for all of the source tarballs in a local directory
# before going to the Internet to fetch them.
SOURCE_MIRROR_URL ?= "file://${BSPDIR}/source-mirror/"
INHERIT += "own-mirrors"
# create a shareable cache of source code management backends
BB_GENERATE_MIRROR_TARBALLS = "1"

9. Execute the build


Execute the following commands on the host.

 host]$ cd $HOME/src/fsl-community-bsp/build 
host]$ time bitbake bsec-image

While the image is building, please take note of the following.

The input specifications for the GNU/Linux kernel and U-boot segments of the BSP are in the below files. These specifications include such things as GNU/Linux kernel patch files for i.MX 6 processor features, kernel boot args, kernel load address, cortex specific tuning parameters, etc.

 sources/meta-fsl-arm-extra/conf/machine/imx6dl-riotboard.conf  
sources/poky/meta-yocto/conf/distro/poky.conf
sources/meta-fsl-arm/recipes-kernel/linux/linux-imx.inc
sources/meta-fsl-arm/recipes-kernel/linux/linux-fslc_4_0.bb
sources/poky/meta/conf/machine/include/tune-cortexa9.inc

In part III of this guide, the image will be booted on the target and then audio will be tested, including recording and playback. Continue to part III of this guide.

Continue to Part III

Monday, July 13, 2015

Creating a custom Linux BSP for an ARM Cortex-A9 SBC with Yocto 1.8 - Part I



This guide is an update to "Creating a custom Linux distribution for an ARM® Cortex®-A9 based SBC" and provides directions for building a GNU/Linux BSP for the RioTboard (Internet of Things) with Yocto 1.8 on a 64-bit Fedora 21 GNU/Linux host.  The latest stable version of Yocto 1.8 has been incorporated along with build instructions for version 4.0.7 of the GNU/Linux kernel with i.MX 6 patches, U-boot, audio recording and playback support, and a full kernel and application development environment on the target.

This guide is split into three parts as follows.

I. Creating a custom Linux BSP for the RioTboard (Internet of Things) with Yocto 1.8- Part I
  1. Hardware and software prerequisites.
  2. Required Packages for a 64-bit Fedora 21 Host development system.

II. Creating a custom Linux BSP for the RioTboard with Yocto 1.8 - Part II

  1. Pull the Freescale community BSP platform source code from github. 
  2. Setup the build environment using the predefined imx6dl-riotboard machine.
  3. Create a new layer for the custom Linux distribution.
  4. Customize the image in the meta-bsec layer. 
  5. Create layer.conf file in the meta-bsec layer. 
  6. Create the distribution configuration file in the meta-bsec layer. 
  7. Add the new layer to bblayers.conf.
  8. Customize the local configuration.
  9. Execute the build.
III. Creating a custom Linux BSP for the RioTboard with Yocto 1.8 - Part III
  1. Write the GNU/Linux BSP image to an SD card.
  2. Set the physical switches on the RioTboard to boot from the uSD or SD card.
  3. Connect the target to the necessary peripherals for boot.
  4. Test audio recording, audio playback, and Internet connectivity.

The BSP will consist of a GNU/Linux 4.0.7 kernel, an EXT3 root filesystem, and the U-Boot bootloader.  All components will be compiled from the latest, public sources.  The GNU/Linux system will include support for audio recording and playback via the RioTboard's MIC In and Audio Out jacks. Support will be built for ethernet, ipv4, bluetooth, USB host and USB gadget, and an ssh server.  The final target image will also contain native ARM compilers, a full SDK, strace, GDB, package management tools, and the GNU/Linux 4.0.7 kernel source code with i.MX 6 patches already applied.

In the first guide for Yocto 1.7, a custom distribution and target image was created by extending the core-image-minimal image.  In this guide, a custom distribution and target image will be created by extending the core-image-full-cmdline image.  The resulting target image will be larger in size but will include a much richer set of features for kernel and application level development and debugging on the target.

Finally, Yocto will be configured so that all source packages are archived in their original format with accompanying license files.

To start with, please read Setting up an ARM® Cortex®-A9 based SBC which outlines the necessary components to get started.  A microphone and a set of powered speakers will be needed, both with 3.5mm connectors.  An Audio-Technica ATR4650 microphone and a pair of Logitech S-00134 powered speakers will be onnected to the RioTboard.  These will be needed for testing audio recording and playback.

1. Hardware and software prerequisites



Host Operating System

Fedora release 21 for x86_64
GNU/Linux kernel 4.0.7-200.fc21.x86_64 #1 SMP

Host Hardware

Intel(R) Core(TM) i7-4600U CPU @ 2.10GHz
Physical Memory 12 GB
My /home partition is 414 GB and resides on a solid state hard drive.


The Yocto build requires a large amount of space so it is recommend keeping a scratch area in the /home partition of at least 100 GB.

2. Required Packages for a 64-bit Fedora 21 Host development system


from the Yocto Project Mega Manual Revision 1.8

Execute the following commands on the host.

 host]$ sudo yum install gawk make wget tar bzip2 gzip python unzip perl patch \
diffutils diffstat git cpp gcc gcc-c++ glibc-devel texinfo chrpath \
ccache perl-Data-Dumper perl-Text-ParseWords perl-Thread-Queue socat \
findutils which
host]$ sudo yum install SDL-devel xterm perl-Thread-Queue
host]$ sudo yum install make docbook-style-dsssl docbook-style-xsl \
docbook-dtds docbook-utils fop libxslt dblatex xmlto xsltproc
host]$ sudo yum install autoconf automake libtool glib2-devel

In Part II, the  source code for the kernel, boot loader, and root file system packages will be pulled.  All components will then be built from source and the GNU/Linux BSP image will be created for the target.

Continue to Part II