meta-intel-iot-main

This BSP layer provides information on building Yocto Project*-based BSP
on Intel IoT platforms.

I. Overview
II. Yocto Project Compatibility
III. Getting Started
IV. Setup
    a. Preferred Machine information
    b. Set Preferred Gstreamer / Media versions if any
    c. Set DISTRO_FEATURES if any
    d. Additional and Special Usecases Variables
V. Supported Hardware
VI. Dependencies
VII. Maintenance
VIII. License

I. Overview

This is the location of Intel IoTG maintained Yocto Project*-based BSP For e.g. if a developer need to use the latest development version of
oe-core or meta-intel source , they have the flexibility here to
add it and use it

II. Yocto Project Compatibility

The BSPs contained in this layer are compatible with the Yocto Project
as per the requirements listed here:

a. kirkstone

III. Getting Started

git clone git://github.com/openembedded/openembedded-core.git
cd openembedded-core
git clone git://github.com/openembedded/bitbake.git
git clone https://git.yoctoproject.org/git/meta-intel

For EA custormer, please use:
git clone https://github.com/otcshare/IOTG-Yocto-ESE-Main.git  meta-intel-iot-main

For other, please use:
git clone https://github.com/intel/iotg-yocto-ese-main.git meta-intel-iot-main

$ . ./oe-init-build-env

Add meta-intel and meta-intel-iot-main overlay

bitbake-layers add-layer ../meta-intel
bitbake-layers add-layer ../meta-intel-iot-main

Check conf/bblayers.conf to see that meta-intel and meta-intel-iot-main is added to layer mix e.g.

BBLAYERS ?= " \
/path/to/openembedded-core/meta \
/path/to/meta-intel \
/path/to/layer/meta-intel-iot-main \
"

IV. Setup

User / Developer may need to add various configurations mentioned below
in local.conf based on their feature need.

For eg. this layer will help to use the development version of gstreamer
by providing the PREFERRED_VERSION mentioned below.

a. Preferred Machine information

MACHINE = "intel-corei7-64"

b. Set Preferred Gstreamer / Media versions if any

PREFERRED_VERSION_gstreamer1.0="{version number}%"
e.g.
PREFERRED_VERSION_gstreamer1.0="1.19.%"

c. Set `DISTRO_FEATURES` if any

DISTRO_FEATURES:append = " opengl systemd"

when systemd added as DISTO_FEATURES please add init_manager

VIRTUAL-RUNTIME_init_manager = "systemd"

d. Additional and Special Use cases Variables

For ffmpeg its needs commercial license flag

LICENSE_FLAGS_ACCEPTED += "commercial"

Special Purpose Bitbake Recipes and Classes

Mender Support Initramfs

mender-initramfs and mender-init are musl and eudev init based minimalist initramfs environment. These are meant to be built with:

TCLIBC = "musl"
PREFERRED_PROVIDER_virtual/kernel = "linux-dummy"
VIRTUAL-RUNTIME_init_manager = "sysvinit"

The image assumes the boot disk contains at least 5 partitions, with the file system and GPT disk label (not to be confused with the file system label itself) of:

efi
primary
secondary
data
swap

The partition labeled efi is the EFI System Partition, while swap is a Linux swap partition. Other partitions may be of arbitrary file system.

See scripts/lib/wic/canned-wks/mender-io.wks.in for an example layout. These partitions may be of any arbitrary size, although primary and secondary must be of equal size if mender is to be used.

The data partition contains the user home directory and the /etc directory, these are then bind mounted onto position by the initramfs startup before passing control to the system init daemon (e.g. systemd). This is done so that configuration modifications and user home contents persist across mender updates.

See classes/mender-persistent.bbclass for details on how files on the image is post-processed in the end of the do_rootfs task.

It is recommended to use the bitbake multiconfig feature to integrate these images as dependencies for the main Yocto Linux image.

mender-reconf

This recipe installs a template of the mender configuration file used by mender-init to reconfigure mender disk paths as they are found during the Linux startup process.

mender-relabel

This recipe installs a script that relabels a file system after a mender update so the mender-init startup process can find it upon the next reboot.

ese-image-features.bbclass and secure boot

This class is primarily used to support secure boot for Yocto Linux BSPs. While meta-intel also provides secure boot support via systemd-boot by signing the boot loader, kernel and initramfs as a single EFI PE executable, the approach taken by ese-image-features is done with shim and grub. This approach is done to support mender grub environment settings to switch between primary and secondary partitions.

The boot process diagram is similar to: https://access.redhat.com/articles/5254641

The shim executable is signed by the Database (DB) key, which itself contains the Machine Owner Key (MOK). Grub and the kernel is signed with the MOK keys.

Another caveat for favoring grub over systemd-boot is that most UEFI implementations do not provide a Simple File System protocol for file systems such as EXT4 typically used by Linux root firestorms. To ensure mender updates on the BSP kernel and its modules are performed atomically, it is necessary that the kernel and its modules are stored on the same partition.

The PEM formatted keys used in the Yocto Linux image build process are available in ${TMPDIR}/deploy/images/${MACHINE}/secure-boot-certificates after the build process completes.

V. Supported Hardware

The following boards / platforms undergo regular basic testing.

CML-S RVP
EHL RVP
TGL-U & TGL-H RVP
ADL-S RVP / CRB
ICL-D RVP
KMB

VI. Dependencies

This layer depends on:

URI: git://github.com/openembedded/openembedded-core.git
branch: kirkstone
revision: HEAD

URI: git://github.com/openembedded/bitbake.git
branch: 2.00
revision: HEAD

URI: https://git.yoctoproject.org/git/meta-intel
branch: master
revision: HEAD

VII. Maintenance

Maintainers:

Yong, Jonathan jonathan.yong@intel.com

VIII. License

All metadata is MIT licensed unless otherwise stated. Source code included
in tree for individual recipes is under the LICENSE stated in each recipe
(.bb file) unless otherwise stated.

nros/iotg-yocto-ese-main