[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>

arch/s390/include/asm/qdio.h

@@ -299,7 +299,13 @@ struct qdio_ssqd_desc {
 	u8 mbccnt;
 	u16 qdioac2;
 	u64 sch_token;
-	u64:64;
+	u8 mro;
+	u8 mri;
+	u8:8;
+	u8 sbalic;
+	u16:16;
+	u8:8;
+	u8 mmwc;
 } __attribute__ ((packed));
 
 /* params are: ccw_device, qdio_error, queue_number,

drivers/s390/cio/qdio.h

@@ -203,6 +203,9 @@ struct qdio_output_q {
 	/* PCIs are enabled for the queue */
 	int pci_out_enabled;
 
+	/* IQDIO: output multiple buffers (enhanced SIGA) */
+	int use_enh_siga;
+
 	/* timer to check for more outbound work */
 	struct timer_list timer;
 };

drivers/s390/cio/qdio_main.c

@@ -316,6 +316,9 @@ static inline int qdio_do_siga_output(struct qdio_q *q, unsigned int *busy_bit)
 	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 @@ int qdio_establish(struct qdio_initialize *init_data)
 	}
 
 	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 @@ static void handle_outbound(struct qdio_q *q, unsigned int callflags,
 		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;
 	}