On Mon, Aug 28, 2023 at 05:13:09PM -0400, Nícolas F. R. A. Prado wrote: > > Regressions that cause a device to no longer be probed by a driver can > have a big impact on the platform's functionality, and despite being > relatively common there isn't currently any generic test to detect them. > As an example, bootrr [1] does test for device probe, but it requires > defining the expected probed devices for each platform. > > Given that the Devicetree already provides a static description of > devices on the system, it is a good basis for building such a test on > top. > > This series introduces a test to catch regressions that prevent devices > from probing. > > Patches 1 and 2 extend the existing dt-extract-compatibles to be able to > output only the compatibles that can be expected to match a Devicetree > node to a driver. Patch 2 adds a kselftest that walks over the > Devicetree nodes on the current platform and compares the compatibles to > the ones on the list, and on an ignore list, to point out devices that > failed to be probed. > > A compatible list is needed because not all compatibles that can show up > in a Devicetree node can be used to match to a driver, for example the > code for that compatible might use "OF_DECLARE" type macros and avoid > the driver framework, or the node might be controlled by a driver that > was bound to a different node. > > An ignore list is needed for the few cases where it's common for a > driver to match a device but not probe, like for the "simple-mfd" > compatible, where the driver only probes if that compatible is the > node's first compatible. > > The reason for parsing the kernel source instead of relying on > information exposed by the kernel at runtime (say, looking at modaliases > or introducing some other mechanism), is to be able to catch issues > where a config was renamed or a driver moved across configs, and the > .config used by the kernel not updated accordingly. We need to parse the > source to find all compatibles present in the kernel independent of the > current config being run. > > [1] https://github.com/kernelci/bootrr > > Changes in v3: > - Added DT selftest path to MAINTAINERS > - Enabled device probe test for nodes with 'status = "ok"' > - Added pass/fail/skip totals to end of test output > > Changes in v2: > - Extended dt-extract-compatibles script to be able to extract driver > matching compatibles, instead of adding a new one in Coccinelle > - Made kselftest output in the KTAP format > > Nícolas F. R. A. Prado (3): > dt: dt-extract-compatibles: Handle cfile arguments in generator > function > dt: dt-extract-compatibles: Add flag for driver matching compatibles > kselftest: Add new test for detecting unprobed Devicetree devices > > MAINTAINERS | 1 + > scripts/dtc/dt-extract-compatibles | 74 +++++++++++++---- > tools/testing/selftests/Makefile | 1 + > tools/testing/selftests/dt/.gitignore | 1 + > tools/testing/selftests/dt/Makefile | 21 +++++ > .../selftests/dt/compatible_ignore_list | 1 + > tools/testing/selftests/dt/ktap_helpers.sh | 70 ++++++++++++++++ > .../selftests/dt/test_unprobed_devices.sh | 83 +++++++++++++++++++ > 8 files changed, 236 insertions(+), 16 deletions(-) > create mode 100644 tools/testing/selftests/dt/.gitignore > create mode 100644 tools/testing/selftests/dt/Makefile > create mode 100644 tools/testing/selftests/dt/compatible_ignore_list > create mode 100644 tools/testing/selftests/dt/ktap_helpers.sh > create mode 100755 tools/testing/selftests/dt/test_unprobed_devices.sh Hi Rob, gentle ping on this series. I take it you'll be merging this through your tree, so I've added Shuah's R-b that she supplied on v2 for the kselftest patch. Thanks, Nícolas
