IB/hfi1: OPFN support discovery

OPFN (Omni Path Feature Negotiation) support discovery allows a RC QP to
announce that it supports OPFN and also discover if OPFN is supported by
the peer QP. OPFN parameter negotiation is skipped unless OPFN support is
first discovered. OPFN support is announced by claiming what was
the reserved bit in dword 1 of OmniPath modified base transport header
in requests and responses.

Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: Mitko Haralanov <mitko.haralanov@intel.com>
Signed-off-by: Kaike Wan <kaike.wan@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/hw/hfi1/hfi.h

@@ -73,6 +73,7 @@
 
 #include "chip_registers.h"
 #include "common.h"
+#include "opfn.h"
 #include "verbs.h"
 #include "pio.h"
 #include "chip.h"

drivers/infiniband/hw/hfi1/opfn.h

@@ -0,0 +1,53 @@
+/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) */
+/*
+ * Copyright(c) 2018 Intel Corporation.
+ *
+ */
+#ifndef _HFI1_OPFN_H
+#define _HFI1_OPFN_H
+
+/**
+ * DOC: Omni Path Feature Negotion (OPFN)
+ *
+ * OPFN is a discovery protocol for Intel Omni-Path fabric that
+ * allows two RC QPs to negotiate a common feature that both QPs
+ * can support. Currently, the only OPA feature that OPFN
+ * supports is TID RDMA.
+ *
+ * Architecture
+ *
+ * OPFN involves the communication between two QPs on the HFI
+ * level on an Omni-Path fabric, and ULPs have no knowledge of
+ * OPFN at all.
+ *
+ * Implementation
+ *
+ * OPFN extends the existing IB RC protocol with the following
+ * changes:
+ * -- Uses Bit 24 (reserved) of DWORD 1 of Base Transport
+ *    Header (BTH1) to indicate that the RC QP supports OPFN;
+ * -- Uses a combination of RC COMPARE_SWAP opcode (0x13) and
+ *    the address U64_MAX (0xFFFFFFFFFFFFFFFF) as an OPFN
+ *    request; The 64-bit data carried with the request/response
+ *    contains the parameters for negotiation and will be
+ *    defined in tid_rdma.c file;
+ * -- Defines IB_WR_RESERVED3 as IB_WR_OPFN.
+ *
+ * The OPFN communication will be triggered when an RC QP
+ * receives a request with Bit 24 of BTH1 set. The responder QP
+ * will then post send an OPFN request with its local
+ * parameters, which will be sent to the requester QP once all
+ * existing requests on the responder QP side have been sent.
+ * Once the requester QP receives the OPFN request, it will
+ * keep a copy of the responder QP's parameters, and return a
+ * response packet with its own local parameters. The responder
+ * QP receives the response packet and keeps a copy of the requester
+ * QP's parameters. After this exchange, each side has the parameters
+ * for both sides and therefore can select the right parameters
+ * for future transactions
+ */
+
+/* STL Verbs Extended */
+#define IB_BTHE_E_SHIFT           24
+
+#endif /* _HFI1_OPFN_H */

drivers/infiniband/hw/hfi1/rc.c

@@ -89,8 +89,8 @@ static int make_rc_ack(struct hfi1_ibdev *dev, struct rvt_qp *qp,
 	struct rvt_ack_entry *e;
 	u32 hwords;
 	u32 len;
-	u32 bth0;
-	u32 bth2;
+	u32 bth0, bth2;
+	u32 bth1 = qp->remote_qpn | (HFI1_CAP_IS_KSET(OPFN) << IB_BTHE_E_SHIFT);
 	int middle = 0;
 	u32 pmtu = qp->pmtu;
 	struct hfi1_qp_priv *priv = qp->priv;
@@ -229,7 +229,7 @@ normal:
 	ps->s_txreq->sde = priv->s_sde;
 	ps->s_txreq->s_cur_size = len;
 	ps->s_txreq->hdr_dwords = hwords;
-	hfi1_make_ruc_header(qp, ohdr, bth0, bth2, middle, ps);
+	hfi1_make_ruc_header(qp, ohdr, bth0, bth1, bth2, middle, ps);
 	return 1;
 
 bail:
@@ -262,8 +262,8 @@ int hfi1_make_rc_req(struct rvt_qp *qp, struct hfi1_pkt_state *ps)
 	struct rvt_swqe *wqe;
 	u32 hwords;
 	u32 len;
-	u32 bth0 = 0;
-	u32 bth2;
+	u32 bth0 = 0, bth2;
+	u32 bth1 = qp->remote_qpn | (HFI1_CAP_IS_KSET(OPFN) << IB_BTHE_E_SHIFT);
 	u32 pmtu = qp->pmtu;
 	char newreq;
 	int middle = 0;
@@ -693,6 +693,7 @@ no_flow_control:
 		qp,
 		ohdr,
 		bth0 | (qp->s_state << 24),
+		bth1,
 		bth2,
 		middle,
 		ps);
@@ -796,6 +797,11 @@ static inline void hfi1_make_rc_ack_9B(struct hfi1_packet *packet,
 	if (qp->s_mig_state == IB_MIG_MIGRATED)
 		bth0 |= IB_BTH_MIG_REQ;
 	bth1 = (!!is_fecn) << IB_BECN_SHIFT;
+	/*
+	 * Inline ACKs go out without the use of the Verbs send engine, so
+	 * we need to set the STL Verbs Extended bit here
+	 */
+	bth1 |= HFI1_CAP_IS_KSET(OPFN) << IB_BTHE_E_SHIFT;
 	hfi1_make_bth_aeth(qp, ohdr, bth0, bth1);
 }
 

drivers/infiniband/hw/hfi1/ruc.c

@@ -250,7 +250,6 @@ static inline void hfi1_make_ruc_bth(struct rvt_qp *qp,
 				     struct ib_other_headers *ohdr,
 				     u32 bth0, u32 bth1, u32 bth2)
 {
-	bth1 |= qp->remote_qpn;
 	ohdr->bth[0] = cpu_to_be32(bth0);
 	ohdr->bth[1] = cpu_to_be32(bth1);
 	ohdr->bth[2] = cpu_to_be32(bth2);
@@ -272,13 +271,13 @@ static inline void hfi1_make_ruc_bth(struct rvt_qp *qp,
  */
 static inline void hfi1_make_ruc_header_16B(struct rvt_qp *qp,
 					    struct ib_other_headers *ohdr,
-					    u32 bth0, u32 bth2, int middle,
+					    u32 bth0, u32 bth1, u32 bth2,
+					    int middle,
 					    struct hfi1_pkt_state *ps)
 {
 	struct hfi1_qp_priv *priv = qp->priv;
 	struct hfi1_ibport *ibp = ps->ibp;
 	struct hfi1_pportdata *ppd = ppd_from_ibp(ibp);
-	u32 bth1 = 0;
 	u32 slid;
 	u16 pkey = hfi1_get_pkey(ibp, qp->s_pkey_index);
 	u8 l4 = OPA_16B_L4_IB_LOCAL;
@@ -360,12 +359,12 @@ static inline void hfi1_make_ruc_header_16B(struct rvt_qp *qp,
  */
 static inline void hfi1_make_ruc_header_9B(struct rvt_qp *qp,
 					   struct ib_other_headers *ohdr,
-					   u32 bth0, u32 bth2, int middle,
+					   u32 bth0, u32 bth1, u32 bth2,
+					   int middle,
 					   struct hfi1_pkt_state *ps)
 {
 	struct hfi1_qp_priv *priv = qp->priv;
 	struct hfi1_ibport *ibp = ps->ibp;
-	u32 bth1 = 0;
 	u16 pkey = hfi1_get_pkey(ibp, qp->s_pkey_index);
 	u16 lrh0 = HFI1_LRH_BTH;
 	u8 extra_bytes = -ps->s_txreq->s_cur_size & 3;
@@ -415,7 +414,7 @@ static inline void hfi1_make_ruc_header_9B(struct rvt_qp *qp,
 
 typedef void (*hfi1_make_ruc_hdr)(struct rvt_qp *qp,
 				  struct ib_other_headers *ohdr,
-				  u32 bth0, u32 bth2, int middle,
+				  u32 bth0, u32 bth1, u32 bth2, int middle,
 				  struct hfi1_pkt_state *ps);
 
 /* We support only two types - 9B and 16B for now */
@@ -425,7 +424,7 @@ static const hfi1_make_ruc_hdr hfi1_ruc_header_tbl[2] = {
 };
 
 void hfi1_make_ruc_header(struct rvt_qp *qp, struct ib_other_headers *ohdr,
-			  u32 bth0, u32 bth2, int middle,
+			  u32 bth0, u32 bth1, u32 bth2, int middle,
 			  struct hfi1_pkt_state *ps)
 {
 	struct hfi1_qp_priv *priv = qp->priv;
@@ -446,7 +445,8 @@ void hfi1_make_ruc_header(struct rvt_qp *qp, struct ib_other_headers *ohdr,
 	priv->s_ahg->ahgidx = 0;
 
 	/* Make the appropriate header */
-	hfi1_ruc_header_tbl[priv->hdr_type](qp, ohdr, bth0, bth2, middle, ps);
+	hfi1_ruc_header_tbl[priv->hdr_type](qp, ohdr, bth0, bth1, bth2, middle,
+					    ps);
 }
 
 /* when sending, force a reschedule every one of these periods */

drivers/infiniband/hw/hfi1/uc.c

@@ -271,7 +271,8 @@ int hfi1_make_uc_req(struct rvt_qp *qp, struct hfi1_pkt_state *ps)
 	ps->s_txreq->ss = &qp->s_sge;
 	ps->s_txreq->s_cur_size = len;
 	hfi1_make_ruc_header(qp, ohdr, bth0 | (qp->s_state << 24),
-			     mask_psn(qp->s_psn++), middle, ps);
+			     qp->remote_qpn, mask_psn(qp->s_psn++),
+			     middle, ps);
 	return 1;
 
 done_free_tx:

drivers/infiniband/hw/hfi1/verbs.h

@@ -72,6 +72,7 @@ struct hfi1_packet;
 
 #include "iowait.h"
 #include "tid_rdma.h"
+#include "opfn.h"
 
 #define HFI1_MAX_RDMA_ATOMIC     16
 
@@ -356,7 +357,7 @@ u32 hfi1_make_grh(struct hfi1_ibport *ibp, struct ib_grh *hdr,
 		  const struct ib_global_route *grh, u32 hwords, u32 nwords);
 
 void hfi1_make_ruc_header(struct rvt_qp *qp, struct ib_other_headers *ohdr,
-			  u32 bth0, u32 bth2, int middle,
+			  u32 bth0, u32 bth1, u32 bth2, int middle,
 			  struct hfi1_pkt_state *ps);
 
 void _hfi1_do_send(struct work_struct *work);