diff options
| author | Simon Glass <sjg@chromium.org> | 2024-11-20 08:36:41 -0700 |
|---|---|---|
| committer | Tom Rini <trini@konsulko.com> | 2025-01-14 11:42:51 -0600 |
| commit | 6995f2c8be901b5f3f4183ccc4a58c209e8bce52 (patch) | |
| tree | 92f8addda6ee3a888101a736c1fb7c5e5d5f719c /doc | |
| parent | 21dd873572a01d74bfdfceb7a30b056f8ccba187 (diff) | |
common: Move autoprobe out to board init
Rather than doing autoprobe within the driver model code, move it out to
the board-init code. This makes it clear that it is a separate step from
binding devices.
For now this is always done twice, before and after relocation, but we
should discuss whether it might be possible to drop the post-relocation
probe.
For boards with SPL, the autoprobe is still done there as well.
Note that with this change, autoprobe happens after the
EVT_DM_POST_INIT_R/F events are sent, rather than before.
Link: https://lore.kernel.org/u-boot/20240626235717.272219-1-marex@denx.de/
Signed-off-by: Simon Glass <sjg@chromium.org>
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/develop/driver-model/design.rst | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/doc/develop/driver-model/design.rst b/doc/develop/driver-model/design.rst index 8c2c81d7ac9..92f638a0204 100644 --- a/doc/develop/driver-model/design.rst +++ b/doc/develop/driver-model/design.rst @@ -842,6 +842,23 @@ steps (see device_probe()): cause the uclass to do some housekeeping to record the device as activated and 'known' by the uclass. +For some platforms, certain devices must be probed to get the platform into +a working state. To help with this, drivers marked with DM_FLAG_PROBE_AFTER_BIND +will be probed immediately after all devices are bound. For now, this happens in +SPL, before relocation and after relocation. See the call to ``dm_autoprobe()`` +for where this is done. + +The auto-probe feature is tricky because it bypasses the normal ordering of +probing. General, if device A (e.g. video) needs device B (e.g. clock), then +A's probe() method uses ``clk_get_by_index()`` and B is probed before A. But +A is only probed when it is used. Therefore care should be taken when using +auto-probe, limiting it to devices which truly are essential, such as power +domains or critical clocks. + +See here for more discussion of this feature: + +:Link: https://patchwork.ozlabs.org/project/uboot/patch/20240626235717.272219-1-marex@denx.de/ + Running stage ^^^^^^^^^^^^^ |