OpenEmbedded BSP layer for DH electronics i.MX platforms

This layer provides BSP for DH electronics i.MX platforms.

Dependencies

This layer depends on:

URI: https://git.yoctoproject.org/poky
- branch: kirkstone or scarthgap
- layers: meta
URI: https://source.denx.de/denx/meta-mainline-common.git
- branch: main

Building image

The OE build of this layer can be set up either manually or automatically using the KAS tool. Both options yield equal result. The manual option is more flexible, the kas option is easier for starters.

Building image (kas)

The KAS tool downloads select OE layers, emits matching bblayers.conf and local.conf, sets up required OE build variables and even executes the build. The tool also provides menu-based build configuration.

Refer to kas-dhsom repository for build instructions and YAML files.

Building image (manual)

A good starting point for setting up the build environment is is the official Yocto Project wiki.

Before attempting the build, the following metalayer git repositories shall be cloned into a location accessible to the build system and a branch listed below shall be checked out. The examples below will use /path/to/OE/ as a location of the metalayers.

https://source.denx.de/denx/meta-mainline-common.git (branch: main)
https://github.com/dh-electronics/meta-dhsom-imx-bsp.git (branch: main)
https://git.yoctoproject.org/poky (branch: kirkstone or scarthgap)

With all the source artifacts in place, proceed with setting up the build using oe-init-build-env as specified in the Yocto Project wiki.

In addition to the content in the wiki, the aforementioned metalayers shall be referenced in bblayers.conf in this order:

BBLAYERS ?= " \
  /path/to/OE/poky/meta \
  /path/to/OE/meta-mainline-common \
  /path/to/OE/meta-dhsom-imx-bsp \
  "

The following specifics should be placed into local.conf:

MACHINE = "dh-imx6-dhcom-pdk2"
DISTRO = "nodistro"

Note that MACHINE must be either of:

dh-imx6-dhcom-pdk2
dh-imx6-dhcom-picoitx
dh-imx6ull-dhcom-pdk2
dh-imx8mp-dhcom-pdk2
dh-imx8mp-dhcom-pdk3

Adapt the suffixes of all the files and names of directories further in this documentation according to MACHINE.

Both local.conf and bblayers.conf are included verbatim in full at the end of this readme.

Once the configuration is complete, a basic demo system image suitable for evaluation can be built using:

$ bitbake core-image-minimal

Once the build completes, the images are available in:

tmp-glibc/deploy/images/dh-imx6-dhcom-pdk2/

The SD card image is specifically in:

core-image-minimal-dh-imx6-dhcom-pdk2.wic

And shall be written to the SD card using dd:

$ dd if=core-image-minimal-dh-imx6-dhcom-pdk2.wic of=/dev/sdX bs=8M

Example local.conf

MACHINE = "dh-imx6-dhcom-pdk2"
DL_DIR = "/path/to/OE/downloads"
DISTRO ?= "nodistro"
PACKAGE_CLASSES ?= "package_rpm"
EXTRA_IMAGE_FEATURES = "debug-tweaks"
USER_CLASSES ?= "buildstats"
PATCHRESOLVE = "noop"
BB_DISKMON_DIRS = "\
    STOPTASKS,${TMPDIR},1G,100K \
    STOPTASKS,${DL_DIR},1G,100K \
    STOPTASKS,${SSTATE_DIR},1G,100K \
    STOPTASKS,/tmp,100M,100K \
    HALT,${TMPDIR},100M,1K \
    HALT,${DL_DIR},100M,1K \
    HALT,${SSTATE_DIR},100M,1K \
    HALT,/tmp,10M,1K"
PACKAGECONFIG:append:pn-qemu-native = " sdl"
PACKAGECONFIG:append:pn-nativesdk-qemu = " sdl"
CONF_VERSION = "1"

Example bblayers.conf

# LAYER_CONF_VERSION is increased each time build/conf/bblayers.conf
# changes incompatibly
POKY_BBLAYERS_CONF_VERSION = "2"

BBPATH = "${TOPDIR}"
BBFILES ?= ""

BBLAYERS ?= " \
	/path/to/OE/poky/meta \
	/path/to/OE/meta-mainline-common \
	/path/to/OE/meta-dhsom-imx-bsp \
	"