[S390] qdio: add timestamp for last queue scan time

Add a timestamp per queue and update the timestamp when the queue is
scanned. Add the queue timestamps and the timestamp of the last
adapter interrupt to the debugfs output. The timestamps are useful
for debugging stall conditions.

Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/cio/qdio.h

@@ -290,6 +290,9 @@ struct qdio_q {
 	/* error condition during a data transfer */
 	unsigned int qdio_error;
 
+	/* last scan of the queue */
+	u64 timestamp;
+
 	struct tasklet_struct tasklet;
 	struct qdio_queue_perf_stat q_stats;
 
@@ -449,6 +452,8 @@ static inline int shared_ind(struct qdio_q *q)
 	return references_shared_dsci(i) || has_multiple_inq_on_dsci(i);
 }
 
+extern u64 last_ai_time;
+
 /* prototypes for thin interrupt */
 void qdio_setup_thinint(struct qdio_irq *irq_ptr);
 int qdio_establish_thinint(struct qdio_irq *irq_ptr);