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| author | David Lechner <dlechner@baylibre.com> | 2024-07-09 03:05:29 +0200 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2024-07-09 18:42:32 +0200 |
| commit | ca52aa4c60f76566601b42e935b8a78f0fb4f8eb (patch) | |
| tree | fbe6a59db57f955fcd6f0033614299514281d011 /include | |
| parent | spi: don't unoptimize message in spi_async() (diff) | |
| download | linux-ca52aa4c60f76566601b42e935b8a78f0fb4f8eb.tar.xz linux-ca52aa4c60f76566601b42e935b8a78f0fb4f8eb.zip | |
spi: add defer_optimize_message controller flag
Adding spi_optimize_message() broke the spi-mux driver because it
calls spi_async() from it's transfer_one_message() callback. This
resulted in passing an incorrectly optimized message to the controller.
For example, if the underlying controller has an optimize_message()
callback, this would have not been called and can cause a crash when
the underlying controller driver tries to transfer the message.
Also, since the spi-mux driver swaps out the controller pointer by
replacing msg->spi, __spi_unoptimize_message() was being called with a
different controller than the one used in __spi_optimize_message(). This
could cause a crash when attempting to free the message resources when
__spi_unoptimize_message() is called in spi_finalize_current_message()
since it is being called with a controller that did not allocate the
resources.
This is fixed by adding a defer_optimize_message flag for controllers.
This flag causes all of the spi_[maybe_][un]optimize_message() calls to
be a no-op (other than attaching a pointer to the spi device to the
message).
This allows the spi-mux driver to pass an unmodified message to
spi_async() in spi_mux_transfer_one_message() after the spi device has
been swapped out. This causes __spi_optimize_message() and
__spi_unoptimize_message() to be called only once per message and with
the correct/same controller in each case.
Reported-by: Oleksij Rempel <o.rempel@pengutronix.de>
Closes: https://lore.kernel.org/linux-spi/Zn6HMrYG2b7epUxT@pengutronix.de/
Reported-by: Marc Kleine-Budde <mkl@pengutronix.de>
Closes: https://lore.kernel.org/linux-spi/20240628-awesome-discerning-bear-1621f9-mkl@pengutronix.de/
Fixes: 7b1d87af14d9 ("spi: add spi_optimize_message() APIs")
Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20240708-spi-mux-fix-v1-2-6c8845193128@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/spi/spi.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 98fdef6e28f2..67b9a15a5330 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -533,6 +533,9 @@ extern struct spi_device *spi_new_ancillary_device(struct spi_device *spi, u8 ch * @queue_empty: signal green light for opportunistically skipping the queue * for spi_sync transfers. * @must_async: disable all fast paths in the core + * @defer_optimize_message: set to true if controller cannot pre-optimize messages + * and needs to defer the optimization step until the message is actually + * being transferred * * Each SPI controller can communicate with one or more @spi_device * children. These make a small bus, sharing MOSI, MISO and SCK signals @@ -776,6 +779,7 @@ struct spi_controller { /* Flag for enabling opportunistic skipping of the queue in spi_sync */ bool queue_empty; bool must_async; + bool defer_optimize_message; }; static inline void *spi_controller_get_devdata(struct spi_controller *ctlr) |