[S390] qdio enhanced SIGA (iqdio) support.

Add support for z10 HiperSockets multiwrite SBALs on output
queues. This is used on LPAR with EDDP enabled devices.

Signed-off-by: Klaus-Dieter Wacker <kdwacker@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/cio/qdio_main.c b/drivers/s390/cio/qdio_main.c
index 719066e..a50682d 100644
--- a/drivers/s390/cio/qdio_main.c
+++ b/drivers/s390/cio/qdio_main.c
@@ -316,6 +316,9 @@
 	unsigned int fc = 0;
 	unsigned long schid;
 
+	if (q->u.out.use_enh_siga) {
+		fc = 3;
+	}
 	if (!is_qebsm(q))
 		schid = *((u32 *)&q->irq_ptr->schid);
 	else {
@@ -1449,6 +1452,8 @@
 	}
 
 	qdio_setup_ssqd_info(irq_ptr);
+	sprintf(dbf_text, "qDmmwc%2x", irq_ptr->ssqd_desc.mmwc);
+	QDIO_DBF_TEXT2(0, setup, dbf_text);
 	sprintf(dbf_text, "qib ac%2x", irq_ptr->qib.ac);
 	QDIO_DBF_TEXT2(0, setup, dbf_text);
 
@@ -1621,12 +1626,21 @@
 		if (multicast_outbound(q))
 			qdio_kick_outbound_q(q);
 		else
-			/*
-			 * One siga-w per buffer required for unicast
-			 * HiperSockets.
-			 */
-			while (count--)
+			if ((q->irq_ptr->ssqd_desc.mmwc > 1) &&
+			    (count > 1) &&
+			    (count <= q->irq_ptr->ssqd_desc.mmwc)) {
+				/* exploit enhanced SIGA */
+				q->u.out.use_enh_siga = 1;
 				qdio_kick_outbound_q(q);
+			} else {
+				/*
+				* One siga-w per buffer required for unicast
+				* HiperSockets.
+				*/
+				q->u.out.use_enh_siga = 0;
+				while (count--)
+					qdio_kick_outbound_q(q);
+			}
 		goto out;
 	}