From ca52aa4c60f76566601b42e935b8a78f0fb4f8eb Mon Sep 17 00:00:00 2001 From: David Lechner Date: Mon, 8 Jul 2024 20:05:29 -0500 Subject: 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 Closes: https://lore.kernel.org/linux-spi/Zn6HMrYG2b7epUxT@pengutronix.de/ Reported-by: Marc Kleine-Budde 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 Link: https://patch.msgid.link/20240708-spi-mux-fix-v1-2-6c8845193128@baylibre.com Signed-off-by: Mark Brown --- drivers/spi/spi.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) (limited to 'drivers/spi/spi.c') diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 679ee414cbea..0f04e832f9ec 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -2151,7 +2151,8 @@ static void __spi_unoptimize_message(struct spi_message *msg) */ static void spi_maybe_unoptimize_message(struct spi_message *msg) { - if (!msg->pre_optimized && msg->optimized) + if (!msg->pre_optimized && msg->optimized && + !msg->spi->controller->defer_optimize_message) __spi_unoptimize_message(msg); } @@ -4294,6 +4295,11 @@ static int __spi_optimize_message(struct spi_device *spi, static int spi_maybe_optimize_message(struct spi_device *spi, struct spi_message *msg) { + if (spi->controller->defer_optimize_message) { + msg->spi = spi; + return 0; + } + if (msg->pre_optimized) return 0; @@ -4324,6 +4330,13 @@ int spi_optimize_message(struct spi_device *spi, struct spi_message *msg) { int ret; + /* + * Pre-optimization is not supported and optimization is deferred e.g. + * when using spi-mux. + */ + if (spi->controller->defer_optimize_message) + return 0; + ret = __spi_optimize_message(spi, msg); if (ret) return ret; @@ -4350,6 +4363,9 @@ EXPORT_SYMBOL_GPL(spi_optimize_message); */ void spi_unoptimize_message(struct spi_message *msg) { + if (msg->spi->controller->defer_optimize_message) + return; + __spi_unoptimize_message(msg); msg->pre_optimized = false; } -- cgit v1.2.3