@@ -164,6 +164,7 @@ static int spi_mux_probe(struct spi_device *spi)
ctlr->bus_num = -1;
ctlr->dev.of_node = spi->dev.of_node;
ctlr->must_async = true;
+ ctlr->defer_optimize_message = true;
ret = devm_spi_register_controller(&spi->dev, ctlr);
if (ret)
@@ -2132,7 +2132,8 @@ 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);
}
@@ -4270,6 +4271,11 @@ 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;
@@ -4300,6 +4306,13 @@ 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;
@@ -4326,6 +4339,9 @@ 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;
}
@@ -532,6 +532,9 @@ 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
@@ -774,6 +777,7 @@ 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)
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> --- drivers/spi/spi-mux.c | 1 + drivers/spi/spi.c | 18 +++++++++++++++++- include/linux/spi/spi.h | 4 ++++ 3 files changed, 22 insertions(+), 1 deletion(-)