drm/ci: Add jobs to validate devicetrees

Add jobs to run dt_binding_check and dtbs_check. If warnings are seen,
exit with a non-zero error code while configuring them as warning in
the GitLab CI pipeline.

Signed-off-by: Vignesh Raman <[e-mail]>
Acked-by: Helen Koike <[e-mail]>
Reviewed-by: Maxime Ripard <[e-mail]>
Acked-by: Dmitry Baryshkov <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Maxime Ripard <[e-mail]>

drivers/gpu/drm/ci/check-devicetrees.yml

···
+.dt-check-base:
+  stage: static-checks
+  timeout: "30m"
+  variables:
+    GIT_DEPTH: 1
+    FF_USE_NEW_BASH_EVAL_STRATEGY: 'true'
+    SCHEMA: "display:gpu"
+    VENV_PATH: "/tmp/dtcheck-venv"
+  before_script:
+    - apt-get update -qq
+    # Minimum supported version of LLVM for building x86 kernels is 15.0.0.
+    # In mesa-ci containers, LLVM_VERSION is defined as a container-level property and is currently set to 19.
+    - apt-get install -y --no-install-recommends clang-${LLVM_VERSION} lld-${LLVM_VERSION} llvm-${LLVM_VERSION} python3-dev python3-venv python3-pip yamllint
+    - python3 -m venv "${VENV_PATH}"
+    - source "${VENV_PATH}/bin/activate"
+    - pip3 install dtschema
+  script:
+    - drivers/gpu/drm/ci/${SCRIPT_NAME}
+  artifacts:
+    when: on_failure
+    paths:
+      - ${ARTIFACT_FILE}
+  allow_failure:
+    exit_codes:
+      - 102
+
+dtbs-check:arm32:
+  extends:
+    - .build:arm32
+    - .dt-check-base
+  variables:
+    SCRIPT_NAME: "dtbs-check.sh"
+    ARTIFACT_FILE: "dtbs-check.log"
+
+dtbs-check:arm64:
+  extends:
+    - .build:arm64
+    - .dt-check-base
+  variables:
+    SCRIPT_NAME: "dtbs-check.sh"
+    ARTIFACT_FILE: "dtbs-check.log"
+
+dt-binding-check:
+  extends:
+    - .build
+    - .use-debian/x86_64_build
+    - .dt-check-base
+  variables:
+    SCRIPT_NAME: "dt-binding-check.sh"
+    ARTIFACT_FILE: "dt-binding-check.log"

drivers/gpu/drm/ci/dt-binding-check.sh

···
+#!/bin/bash
+# SPDX-License-Identifier: MIT
+
+set -euxo pipefail
+
+VENV_PATH="${VENV_PATH:-/tmp/dtschema-venv}"
+source "${VENV_PATH}/bin/activate"
+
+if ! make -j"${FDO_CI_CONCURRENT:-4}" dt_binding_check \
+        DT_SCHEMA_FILES="${SCHEMA:-}" 2>dt-binding-check.log; then
+    echo "ERROR: 'make dt_binding_check' failed. Please check dt-binding-check.log for details."
+    exit 1
+fi
+
+if [[ -s dt-binding-check.log ]]; then
+    echo "WARNING: dt_binding_check reported warnings. Please check dt-binding-check.log" \
+         "for details."
+    exit 102
+fi

drivers/gpu/drm/ci/dtbs-check.sh

···
+#!/bin/bash
+# SPDX-License-Identifier: MIT
+
+set -euxo pipefail
+
+: "${KERNEL_ARCH:?ERROR: KERNEL_ARCH must be set}"
+: "${LLVM_VERSION:?ERROR: LLVM_VERSION must be set}"
+
+./drivers/gpu/drm/ci/setup-llvm-links.sh
+
+make LLVM=1 ARCH="${KERNEL_ARCH}" defconfig
+
+if ! make -j"${FDO_CI_CONCURRENT:-4}" ARCH="${KERNEL_ARCH}" LLVM=1 dtbs_check \
+        DT_SCHEMA_FILES="${SCHEMA:-}" 2>dtbs-check.log; then
+    echo "ERROR: 'make dtbs_check' failed. Please check dtbs-check.log for details."
+    exit 1
+fi
+
+if [[ -s dtbs-check.log ]]; then
+    echo "WARNING: dtbs_check reported warnings. Please check dtbs-check.log for details."
+    exit 102
+fi

drivers/gpu/drm/ci/gitlab-ci.yml

···
   - drivers/gpu/drm/ci/static-checks.yml
   - drivers/gpu/drm/ci/build.yml
   - drivers/gpu/drm/ci/test.yml
+  - drivers/gpu/drm/ci/check-devicetrees.yml
   - 'https://gitlab.freedesktop.org/gfx-ci/lab-status/-/raw/main/lab-status.yml'
 
 
···
   - git-archive
   - build-for-tests
   - build-only
+  - static-checks
   - code-validation
   - amdgpu
   - i915

drivers/gpu/drm/ci/setup-llvm-links.sh

···
+#!/usr/bin/env bash
+# SPDX-License-Identifier: MIT
+set -euo pipefail
+
+ln -svf "$(which clang++-${LLVM_VERSION})"      /usr/bin/clang++
+ln -svf "$(which clang-${LLVM_VERSION})"        /usr/bin/clang
+ln -svf "$(which ld.lld-${LLVM_VERSION})"       /usr/bin/ld.lld
+ln -svf "$(which lld-${LLVM_VERSION})"          /usr/bin/lld
+ln -svf "$(which llvm-ar-${LLVM_VERSION})"      /usr/bin/llvm-ar
+ln -svf "$(which llvm-nm-${LLVM_VERSION})"      /usr/bin/llvm-nm
+ln -svf "$(which llvm-objcopy-${LLVM_VERSION})" /usr/bin/llvm-objcopy
+ln -svf "$(which llvm-readelf-${LLVM_VERSION})" /usr/bin/llvm-readelf
+ln -svf "$(which llvm-strip-${LLVM_VERSION})"   /usr/bin/llvm-strip