net: ipa: move more code out of gsi_channel_update()

Move the processing done for TX channels in gsi_channel_update()
into gsi_evt_ring_rx_update().  The called function is called for
both RX and TX channels, so rename it to be gsi_evt_ring_update().
As a result, this code no longer assumes events in an event ring are
associated with just one channel.

Because all events in a ring are handled in that function, we can
move the call to gsi_trans_move_complete() there, and can ring the
event ring doorbell there as well after all new events in the ring
have been processed.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ipa/gsi.c

@@ -1344,7 +1344,7 @@ gsi_event_trans(struct gsi *gsi, struct gsi_event *event)
 }
 
 /**
- * gsi_evt_ring_rx_update() - Record lengths of received data
+ * gsi_evt_ring_update() - Update transaction state from hardware
  * @gsi:		GSI pointer
  * @evt_ring_id:	Event ring ID
  * @index:		Event index in ring reported by hardware
@@ -1353,6 +1353,10 @@ gsi_event_trans(struct gsi *gsi, struct gsi_event *event)
  * the buffer.  Every event has a transaction associated with it, and here
  * we update transactions to record their actual received lengths.
  *
+ * When an event for a TX channel arrives we use information in the
+ * transaction to report the number of requests and bytes have been
+ * transferred.
+ *
  * This function is called whenever we learn that the GSI hardware has filled
  * new events since the last time we checked.  The ring's index field tells
  * the first entry in need of processing.  The index provided is the
@@ -1363,7 +1367,7 @@ gsi_event_trans(struct gsi *gsi, struct gsi_event *event)
  *
  * Note that @index always refers to an element *within* the event ring.
  */
-static void gsi_evt_ring_rx_update(struct gsi *gsi, u32 evt_ring_id, u32 index)
+static void gsi_evt_ring_update(struct gsi *gsi, u32 evt_ring_id, u32 index)
 {
 	struct gsi_evt_ring *evt_ring = &gsi->evt_ring[evt_ring_id];
 	struct gsi_ring *ring = &evt_ring->ring;
@@ -1372,10 +1376,12 @@ static void gsi_evt_ring_rx_update(struct gsi *gsi, u32 evt_ring_id, u32 index)
 	u32 event_avail;
 	u32 old_index;
 
-	/* We'll start with the oldest un-processed event.  RX channels
-	 * replenish receive buffers in single-TRE transactions, so we
-	 * can just map that event to its transaction.  Transactions
-	 * associated with completion events are consecutive.
+	/* Starting with the oldest un-processed event, determine which
+	 * transaction (and which channel) is associated with the event.
+	 * For RX channels, update each completed transaction with the
+	 * number of bytes that were actually received.  For TX channels
+	 * associated with a network device, report to the network stack
+	 * the number of transfers and bytes this completion represents.
 	 */
 	old_index = ring->index;
 	event = gsi_ring_virt(ring, old_index);
@@ -1394,6 +1400,10 @@ static void gsi_evt_ring_rx_update(struct gsi *gsi, u32 evt_ring_id, u32 index)
 
 		if (trans->direction == DMA_FROM_DEVICE)
 			trans->len = __le16_to_cpu(event->len);
+		else
+			gsi_trans_tx_completed(trans);
+
+		gsi_trans_move_complete(trans);
 
 		/* Move on to the next event and transaction */
 		if (--event_avail)
@@ -1401,6 +1411,9 @@ static void gsi_evt_ring_rx_update(struct gsi *gsi, u32 evt_ring_id, u32 index)
 		else
 			event = gsi_ring_virt(ring, 0);
 	} while (event != event_done);
+
+	/* Tell the hardware we've handled these events */
+	gsi_evt_ring_doorbell(gsi, evt_ring_id, index);
 }
 
 /* Initialize a ring, including allocating DMA memory for its entries */
@@ -1499,14 +1512,7 @@ static struct gsi_trans *gsi_channel_update(struct gsi_channel *channel)
 	 * the number of transactions and bytes this completion represents
 	 * up the network stack.
 	 */
-	if (channel->toward_ipa)
-		gsi_trans_tx_completed(trans);
-	gsi_evt_ring_rx_update(gsi, evt_ring_id, index);
-
-	gsi_trans_move_complete(trans);
-
-	/* Tell the hardware we've handled these events */
-	gsi_evt_ring_doorbell(gsi, evt_ring_id, index);
+	gsi_evt_ring_update(gsi, evt_ring_id, index);
 
 	return gsi_channel_trans_complete(channel);
 }