ci: Introduce workflow Yocto operations/builds

We include a workflow for checking yocto compliance using the poky
provided script and also a matrix workflow for building the CI supported
build configurations.

Signed-off-by: Andrei Gherzan <andrei.gherzan@huawei.com>

.github/workflows/docker-images/yocto-builder/Dockerfile

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+# SPDX-FileCopyrightText: Andrei Gherzan <andrei.gherzan@huawei.com>
+#
+# SPDX-License-Identifier: MIT
+
+FROM ubuntu:20.04
+
+ARG DEBIAN_FRONTEND="noninteractive"
+RUN apt-get update -qq
+RUN apt-get install -y eatmydata
+
+# Yocto/OE build host dependencies
+# Keep this in sync with
+# https://git.yoctoproject.org/poky/tree/documentation/poky.yaml
+RUN eatmydata apt-get install -qq -y \
+	gawk wget git diffstat unzip texinfo gcc build-essential chrpath \
+	socat cpio python3 python3-pip python3-pexpect xz-utils debianutils \
+	iputils-ping python3-git python3-jinja2 libegl1-mesa libsdl1.2-dev \
+	pylint3 xterm python3-subunit mesa-common-dev zstd liblz4-tool
+
+# en_US.UTF-8 is required by the build system
+RUN eatmydata apt-get install -qq -y locales \
+	&& echo "en_US.UTF-8 UTF-8" > /etc/locale.gen \
+	&& locale-gen
+ENV LANG en_US.utf8
+
+RUN eatmydata apt-get clean && rm -rf /var/lib/apt/lists/*
+
+# Have bash as shell
+RUN echo "dash dash/sh boolean false" | debconf-set-selections \
+ && dpkg-reconfigure dash
+
+# Run under normal user called 'ci'
+RUN useradd --create-home --uid 1000 --shell /usr/bin/bash ci
+USER ci
+WORKDIR /home/ci
+
+COPY ./yocto-builder/entrypoint-yocto-check-layer.sh /
+COPY ./yocto-builder/entrypoint-build.sh /
+COPY ./utils.sh /

.github/workflows/docker-images/yocto-builder/README.md

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+<!--
+SPDX-FileCopyrightText: Andrei Gherzan <andrei.gherzan@huawei.com>
+
+SPDX-License-Identifier: MIT
+-->
+
+# Docker image for builds
+
+This defines the docker image for running Yocto/OE based operations/builds. It
+privides multiple scripts for driving different operations.
+
+## Configuration
+
+The `entrypoint` scripts assumes at runtime that the repository to drive the
+operation against is available under `/work`. This path is to be populated via
+bind mounts when running the container.

.github/workflows/docker-images/yocto-builder/entrypoint-build.sh

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+#!/bin/sh
+
+# SPDX-FileCopyrightText: Andrei Gherzan <andrei.gherzan@huawei.com>
+#
+# SPDX-License-Identifier: MIT
+
+set -ex
+
+# shellcheck disable=SC1091
+. /utils.sh
+
+META_RASPBERRYPI_PATH="/work"
+
+[ -n "$BASE_REF" ] ||
+    error "Target branch is needed. Make sure that is set in BASE_REF."
+[ -d "$META_RASPBERRYPI_PATH/.git" ] ||
+    error "Can't find a git checkout under $META_RASPBERRYPI_PATH ."
+[ -n "$MACHINE" ] ||
+    error "Machine to be used for build not provided."
+[ -n "$IMAGE" ] ||
+    error "Image to build not provided."
+
+TEMP_DIR="$(mktemp -d)"
+cd "$TEMP_DIR"
+
+REPOS=" \
+    git://git.yoctoproject.org/poky.git \
+"
+for repo in $REPOS; do
+    log "Cloning $repo on branch $BASE_REF..."
+    git clone --depth 1 --branch "$BASE_REF" "$repo"
+done
+
+# shellcheck disable=SC1091,SC2240
+. ./poky/oe-init-build-env build
+
+# Build configuration
+printf "\n# ------ ci ------\n" >> conf/local.conf
+[ -z "$SSTATE_DIR" ] || echo SSTATE_DIR = \""$SSTATE_DIR"\" >> conf/local.conf
+[ -z "$DL_DIR" ] || echo DL_DIR = \""$DL_DIR"\" >> conf/local.conf
+[ -z "$DISTRO" ] || echo DISTRO = \""$DISTRO"\" >> conf/local.conf
+cat <<EOCONF >>conf/local.conf
+BB_NUMBER_THREADS = "6"
+PARALLEL_MAKE = "-j 6"
+DISTRO_FEATURES:append = " systemd"
+VIRTUAL-RUNTIME_init_manager = "systemd"
+DISTRO_FEATURES_BACKFILL_CONSIDERED:append = " sysvinit"
+VIRTUAL-RUNTIME_initscripts = "systemd-compat-units"
+EOCONF
+
+# Add the BSP layer
+bitbake-layers add-layer "$META_RASPBERRYPI_PATH"
+
+# Log configs for debugging purposes
+for f in 'conf/local.conf' 'conf/bblayers.conf'; do
+    printf "\n------ %s ------\n" "$f"
+    cat "$f"
+done
+
+# Fire!
+MACHINE="$MACHINE" bitbake "$IMAGE"

.github/workflows/docker-images/yocto-builder/entrypoint-yocto-check-layer.sh

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+#!/bin/sh
+
+# SPDX-FileCopyrightText: Andrei Gherzan <andrei.gherzan@huawei.com>
+#
+# SPDX-License-Identifier: MIT
+
+set -ex
+
+# shellcheck disable=SC1091
+. /utils.sh
+
+GIT_REPO_PATH="/work"
+
+[ -n "$BASE_REF" ] ||
+    error "Target branch is needed. Make sure that is set in BASE_REF."
+[ -d "$GIT_REPO_PATH/.git" ] ||
+    error "Can't find a git checkout under $GIT_REPO_PATH ."
+
+TEMP_DIR="$(mktemp -d)"
+cd "$TEMP_DIR"
+
+REPOS=" \
+    git://git.yoctoproject.org/poky.git \
+"
+for repo in $REPOS; do
+    log "Cloning $repo on branch $BASE_REF..."
+    git clone --depth 1 --branch "$BASE_REF" "$repo"
+done
+
+# shellcheck disable=SC1091,SC2240
+. ./poky/oe-init-build-env build
+yocto-check-layer --with-software-layer-signature-check --debug \
+    "$GIT_REPO_PATH"

.github/workflows/yocto-builds.yml

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+# SPDX-FileCopyrightText: Andrei Gherzan <andrei.gherzan@huawei.com>
+#
+# SPDX-License-Identifier: MIT
+
+name: Builds
+
+on:
+  pull_request:
+
+jobs:
+  build:
+    strategy:
+      fail-fast: true
+      matrix:
+        machine:
+          - raspberrypi
+          - raspberrypi0-2w-64
+          - raspberrypi0-2w
+          - raspberrypi0
+          - raspberrypi0-wifi
+          - raspberrypi2
+          - raspberrypi3-64
+          - raspberrypi3
+          - raspberrypi4-64
+          - raspberrypi4
+          - raspberrypi-cm3
+          - raspberrypi-cm
+        image: [core-image-base]
+        distro: [poky]
+    runs-on: [self-hosted, Linux]
+    name: ${{ matrix.machine }}/${{ matrix.image }}/poky/systemd
+    env:
+        DL_DIR: /var/lib/ci/yocto/downloads
+        SSTATE_DIR: /var/lib/ci/yocto/sstate
+    steps:
+      - name: Checkout the code
+        uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
+      - name: Build a temporary yocto-builder image
+        uses: ./.github/actions/docker-build
+        with:
+          docker_image: yocto-builder
+          id: ${{ github.event.number }}
+      - name: Build the image
+        run: |
+          docker run --rm \
+            -v "$GITHUB_WORKSPACE:/work:ro" \
+            -v "$DL_DIR:$DL_DIR:rw" \
+            -v "$SSTATE_DIR:$SSTATE_DIR:rw" \
+            --env "BASE_REF=$GITHUB_BASE_REF" \
+            --env "MACHINE=${{ matrix.machine }}" \
+            --env "DISTRO=${{ matrix.distro }}" \
+            --env "IMAGE=${{ matrix.image }}" \
+            --env "DL_DIR=$DL_DIR" \
+            --env "SSTATE_DIR=$SSTATE_DIR" \
+            "yocto-builder-${{ github.event.number }}" \
+            /entrypoint-build.sh
+      - name: Cleanup temporary docker image
+        uses: ./.github/actions/docker-clean-image
+        with:
+          docker_image: yocto-builder-${{ github.event.number }}
+        if: always()
+      - name: Cleanup dangling docker images
+        uses: ./.github/actions/docker-clean-dangling
+        if: always()

.github/workflows/yocto-layer.yml

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+# SPDX-FileCopyrightText: Andrei Gherzan <andrei.gherzan@huawei.com>
+#
+# SPDX-License-Identifier: MIT
+
+name: Yocto Compatible
+
+on:
+  pull_request:
+
+jobs:
+  yocto-check-layer:
+    name: Validate with yocto-check-layer
+    runs-on: [self-hosted, Linux]
+    steps:
+    - name: Checkout the code
+      uses: actions/checkout@v2
+      with:
+        fetch-depth: 0
+    - name: Build a temporary yocto-builder image
+      uses: ./.github/actions/docker-build
+      with:
+        docker_image: yocto-builder
+        id: ${{ github.event.number }}
+    - name: Run yocto-check-layer
+      run: |
+        docker run --rm -v "$GITHUB_WORKSPACE:/work:ro" \
+          --env "BASE_REF=$GITHUB_BASE_REF" \
+          "yocto-builder-${{ github.event.number }}" \
+          /entrypoint-yocto-check-layer.sh
+    - name: Cleanup temporary docker image
+      uses: ./.github/actions/docker-clean-image
+      with:
+        docker_image: yocto-builder-${{ github.event.number }}
+      if: always()
+    - name: Cleanup dangling docker images
+      uses: ./.github/actions/docker-clean-dangling
+      if: always()