[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>

2 files changed, 22 insertions, 5 deletions

diff --git a/drivers/s390/cio/qdio.h b/drivers/s390/cio/qdio.h
index af867731a5f4..e3ea1d5f2810 100644
--- a/drivers/s390/cio/qdio.h
+++ b/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;
 };
diff --git a/drivers/s390/cio/qdio_main.c b/drivers/s390/cio/qdio_main.c
index 719066ec0c01..a50682d2a0fa 100644
--- a/drivers/s390/cio/qdio_main.c
+++ b/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;
         }