plat-k3: drivers: Track current_sequence in secure proxy

Currently ti_sci_do_xfer layer and ti_sci_setup_xfer both use the same
shared resource message_sequence. However, If ti_sci_setup_xfer and
ti_sci_do_xfer are in different critical sections and the value of
message_sequence can change between both of them causing the message
validation to fail with following.

"Message with Sequence ID <> not expected".

The proper way to handle this would be a queuing model or putting both
of them in single critical section but that would require some major
refactor or require modifying every ti_sci call.

Tracking the message that is being sent over the secure proxy separately
is something that is also doable and would avoid the race condition
without a queuing model.

Extract the message_sequence from the current message being sent over
secure proxy and check that against the receiving response.

Signed-off-by: Manorit Chawdhry <m-chawdhry@ti.com>

core/arch/arm/plat-k3/drivers/ti_sci.c

@@ -22,6 +22,7 @@
 #include "ti_sci_protocol.h"
 
 static uint8_t message_sequence;
+static uint8_t current_sequence;
 static struct mutex ti_sci_mutex_lock = MUTEX_INITIALIZER;
 static unsigned int ti_sci_spin_lock = SPINLOCK_UNLOCK;
 
@@ -116,7 +117,7 @@ static inline int ti_sci_get_response(struct ti_sci_xfer *xfer)
 		hdr = (struct ti_sci_msg_hdr *)msg->buf;
 
 		/* Sanity check for message response */
-		if (hdr->seq == message_sequence)
+		if (hdr->seq == current_sequence)
 			break;
 
 		IMSG("Message with sequence ID %u is not expected", hdr->seq);
@@ -144,10 +145,14 @@ static inline int ti_sci_get_response(struct ti_sci_xfer *xfer)
 static inline int ti_sci_do_xfer(struct ti_sci_xfer *xfer)
 {
 	struct k3_sec_proxy_msg *msg = &xfer->tx_message;
+	struct ti_sci_msg_hdr *hdr = NULL;
 	int ret = 0;
 
 	mutex_lock(&ti_sci_mutex_lock);
 
+	hdr = (struct ti_sci_msg_hdr *)msg->buf;
+	current_sequence = hdr->seq;
+
 	/* Send the message */
 	ret = k3_sec_proxy_send(msg);
 	if (ret) {