mei: update mei-pxp's component interface with timeouts

In debugging platform or firmware related MEI-PXP connection
issues, having a timeout when clients (such as i915) calling
into mei-pxp's send/receive functions have proven useful as opposed to
blocking forever until the kernel triggers a watchdog panic (when
platform issues are experienced).

Update the mei-pxp component interface send and receive functions
to take in timeouts.

Signed-off-by: Alan Previn <alan.previn.teres.alexis@intel.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Link: https://lore.kernel.org/r/20231011110157.247552-5-tomas.winkler@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 27 insertions, 6 deletions

diff --git a/drivers/misc/mei/pxp/mei_pxp.c b/drivers/misc/mei/pxp/mei_pxp.c
index 9875d16445bb..f77d78fa5054 100644
--- a/drivers/misc/mei/pxp/mei_pxp.c
+++ b/drivers/misc/mei/pxp/mei_pxp.c
@@ -46,10 +46,20 @@ static inline int mei_pxp_reenable(const struct device *dev, struct mei_cl_devic
  * @dev: device corresponding to the mei_cl_device
  * @message: a message buffer to send
  * @size: size of the message
- * Return: 0 on Success, <0 on Failure
+ * @timeout_ms: timeout in milliseconds, zero means wait indefinitely.
+ *
+ * Returns: 0 on Success, <0 on Failure with the following defined failures.
+ *         -ENODEV: Client was not connected.
+ *                  Caller may attempt to try again immediately.
+ *         -ENOMEM: Internal memory allocation failure experienced.
+ *                  Caller may sleep to allow kernel reclaim before retrying.
+ *         -EINTR : Calling thread received a signal. Caller may choose
+ *                  to abandon with the same thread id.
+ *         -ETIME : Request is timed out.
+ *                  Caller may attempt to try again immediately.
  */
 static int
-mei_pxp_send_message(struct device *dev, const void *message, size_t size)
+mei_pxp_send_message(struct device *dev, const void *message, size_t size, unsigned long timeout_ms)
 {
 	struct mei_cl_device *cldev;
 	ssize_t byte;
@@ -60,7 +70,7 @@ mei_pxp_send_message(struct device *dev, const void *message, size_t size)
 
 	cldev = to_mei_cl_device(dev);
 
-	byte = mei_cldev_send(cldev, message, size);
+	byte = mei_cldev_send_timeout(cldev, message, size, timeout_ms);
 	if (byte < 0) {
 		dev_dbg(dev, "mei_cldev_send failed. %zd\n", byte);
 		switch (byte) {
@@ -84,10 +94,21 @@ mei_pxp_send_message(struct device *dev, const void *message, size_t size)
  * @dev: device corresponding to the mei_cl_device
  * @buffer: a message buffer to contain the received message
  * @size: size of the buffer
- * Return: bytes sent on Success, <0 on Failure
+ * @timeout_ms: timeout in milliseconds, zero means wait indefinitely.
+ *
+ * Returns: number of bytes send on Success, <0 on Failure with the following defined failures.
+ *         -ENODEV: Client was not connected.
+ *                  Caller may attempt to try again from send immediately.
+ *         -ENOMEM: Internal memory allocation failure experienced.
+ *                  Caller may sleep to allow kernel reclaim before retrying.
+ *         -EINTR : Calling thread received a signal. Caller will need to repeat calling
+ *                  (with a different owning thread) to retrieve existing unclaimed response
+ *                  (and may discard it).
+ *         -ETIME : Request is timed out.
+ *                  Caller may attempt to try again from send immediately.
  */
 static int
-mei_pxp_receive_message(struct device *dev, void *buffer, size_t size)
+mei_pxp_receive_message(struct device *dev, void *buffer, size_t size, unsigned long timeout_ms)
 {
 	struct mei_cl_device *cldev;
 	ssize_t byte;
@@ -100,7 +121,7 @@ mei_pxp_receive_message(struct device *dev, void *buffer, size_t size)
 	cldev = to_mei_cl_device(dev);
 
 retry:
-	byte = mei_cldev_recv(cldev, buffer, size);
+	byte = mei_cldev_recv_timeout(cldev, buffer, size, timeout_ms);
 	if (byte < 0) {
 		dev_dbg(dev, "mei_cldev_recv failed. %zd\n", byte);
 		switch (byte) {