[media] cec: split the timestamp into an rx and tx timestamp

When transmitting a message and waiting for a reply it would be good
to know the time between when the message was transmitted and when
the reply arrived. With only one timestamp field it was set to when
the reply arrived and the original transmit time was overwritten.

Just taking the timestamp in userspace right before CEC_TRANSMIT is
called is not reliable, since the actual transmit can be delayed if
the CEC bus is busy. Only the driver can fill this in accurately.

So split up the ts field into an rx_ts and a tx_ts. Also move the
status fields to after the 'reply' field: they were placed in a
strange position and make much more sense when grouped with the
other status-related fields.

This patch also makes sure that the timestamp is taken as soon as
possible.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

1 files changed, 12 insertions, 12 deletions

diff --git a/drivers/staging/media/cec/cec-adap.c b/drivers/staging/media/cec/cec-adap.c
index 3925e0ae62a5..ca34339e3eba 100644
--- a/drivers/staging/media/cec/cec-adap.c
+++ b/drivers/staging/media/cec/cec-adap.c
@@ -284,7 +284,7 @@ static void cec_data_cancel(struct cec_data *data)
 		list_del_init(&data->list);
 
 	/* Mark it as an error */
-	data->msg.ts = ktime_get_ns();
+	data->msg.tx_ts = ktime_get_ns();
 	data->msg.tx_status = CEC_TX_STATUS_ERROR |
 			      CEC_TX_STATUS_MAX_RETRIES;
 	data->attempts = 0;
@@ -459,6 +459,7 @@ void cec_transmit_done(struct cec_adapter *adap, u8 status, u8 arb_lost_cnt,
 {
 	struct cec_data *data;
 	struct cec_msg *msg;
+	u64 ts = ktime_get_ns();
 
 	dprintk(2, "cec_transmit_done %02x\n", status);
 	mutex_lock(&adap->lock);
@@ -477,7 +478,7 @@ void cec_transmit_done(struct cec_adapter *adap, u8 status, u8 arb_lost_cnt,
 
 	/* Drivers must fill in the status! */
 	WARN_ON(status == 0);
-	msg->ts = ktime_get_ns();
+	msg->tx_ts = ts;
 	msg->tx_status |= status;
 	msg->tx_arb_lost_cnt += arb_lost_cnt;
 	msg->tx_nack_cnt += nack_cnt;
@@ -561,7 +562,7 @@ static void cec_wait_timeout(struct work_struct *work)
 
 	/* Mark the message as timed out */
 	list_del_init(&data->list);
-	data->msg.ts = ktime_get_ns();
+	data->msg.rx_ts = ktime_get_ns();
 	data->msg.rx_status = CEC_RX_STATUS_TIMEOUT;
 	cec_data_completed(data);
 unlock:
@@ -766,13 +767,14 @@ void cec_received_msg(struct cec_adapter *adap, struct cec_msg *msg)
 	if (WARN_ON(!msg->len || msg->len > CEC_MAX_MSG_SIZE))
 		return;
 
-	mutex_lock(&adap->lock);
-	msg->ts = ktime_get_ns();
+	msg->rx_ts = ktime_get_ns();
 	msg->rx_status = CEC_RX_STATUS_OK;
-	msg->tx_status = 0;
 	msg->sequence = msg->reply = msg->timeout = 0;
+	msg->tx_status = 0;
+	msg->tx_ts = 0;
 	msg->flags = 0;
 
+	mutex_lock(&adap->lock);
 	dprintk(2, "cec_received_msg: %*ph\n", msg->len, msg->msg);
 
 	/* Check if this message was for us (directed or broadcast). */
@@ -794,7 +796,6 @@ void cec_received_msg(struct cec_adapter *adap, struct cec_msg *msg)
 		 */
 		list_for_each_entry(data, &adap->wait_queue, list) {
 			struct cec_msg *dst = &data->msg;
-			u8 dst_reply;
 
 			/* Does the command match? */
 			if ((abort && cmd != dst->msg[1]) ||
@@ -807,11 +808,10 @@ void cec_received_msg(struct cec_adapter *adap, struct cec_msg *msg)
 				continue;
 
 			/* We got a reply */
-			msg->sequence = dst->sequence;
-			msg->tx_status = dst->tx_status;
-			dst_reply = dst->reply;
-			*dst = *msg;
-			dst->reply = dst_reply;
+			memcpy(dst->msg, msg->msg, msg->len);
+			dst->len = msg->len;
+			dst->rx_ts = msg->rx_ts;
+			dst->rx_status = msg->rx_status;
 			if (abort) {
 				dst->reply = 0;
 				dst->rx_status |= CEC_RX_STATUS_FEATURE_ABORT;