diff --git a/drivers/infiniband/hw/hfi1/opfn.c b/drivers/infiniband/hw/hfi1/opfn.c
index 2ca0706..82e1889 100644
--- a/drivers/infiniband/hw/hfi1/opfn.c
+++ b/drivers/infiniband/hw/hfi1/opfn.c
@@ -245,6 +245,9 @@ void opfn_qp_init(struct rvt_qp *qp, struct ib_qp_attr *attr, int attr_mask)
 	struct hfi1_qp_priv *priv = qp->priv;
 	unsigned long flags;
 
+	if (attr_mask & IB_QP_RETRY_CNT)
+		priv->s_retry = attr->retry_cnt;
+
 	spin_lock_irqsave(&priv->opfn.lock, flags);
 	if (ibqp->qp_type == IB_QPT_RC && HFI1_CAP_IS_KSET(TID_RDMA)) {
 		struct tid_rdma_params *local = &priv->tid_rdma.local;
diff --git a/drivers/infiniband/hw/hfi1/qp.h b/drivers/infiniband/hw/hfi1/qp.h
index f74e250..d531b76 100644
--- a/drivers/infiniband/hw/hfi1/qp.h
+++ b/drivers/infiniband/hw/hfi1/qp.h
@@ -65,6 +65,7 @@
  * HFI1_S_WAIT_PIO_DRAIN - qp waiting for PIOs to drain
  * HFI1_S_WAIT_TID_SPACE - a QP is waiting for TID resource
  * HFI1_S_WAIT_TID_RESP - waiting for a TID RDMA WRITE response
+ * HFI1_S_WAIT_HALT - halt the first leg send engine
  * HFI1_S_MIN_BIT_MASK - the lowest bit that can be used by hfi1
  */
 #define HFI1_S_AHG_VALID         0x80000000
@@ -72,6 +73,7 @@
 #define HFI1_S_WAIT_PIO_DRAIN    0x20000000
 #define HFI1_S_WAIT_TID_SPACE    0x10000000
 #define HFI1_S_WAIT_TID_RESP     0x08000000
+#define HFI1_S_WAIT_HALT         0x04000000
 #define HFI1_S_MIN_BIT_MASK      0x01000000
 
 /*
diff --git a/drivers/infiniband/hw/hfi1/tid_rdma.c b/drivers/infiniband/hw/hfi1/tid_rdma.c
index a88ac56..954cdc1 100644
--- a/drivers/infiniband/hw/hfi1/tid_rdma.c
+++ b/drivers/infiniband/hw/hfi1/tid_rdma.c
@@ -319,6 +319,7 @@ int hfi1_qp_priv_init(struct rvt_dev_info *rdi, struct rvt_qp *qp,
 	qpriv->flow_state.index = RXE_NUM_TID_FLOWS;
 	qpriv->flow_state.last_index = RXE_NUM_TID_FLOWS;
 	qpriv->flow_state.generation = KERN_GENERATION_RESERVED;
+	qpriv->s_state = TID_OP(WRITE_RESP);
 	qpriv->s_tid_cur = HFI1_QP_WQE_INVALID;
 	qpriv->s_tid_head = HFI1_QP_WQE_INVALID;
 	qpriv->s_tid_tail = HFI1_QP_WQE_INVALID;
@@ -327,6 +328,7 @@ int hfi1_qp_priv_init(struct rvt_dev_info *rdi, struct rvt_qp *qp,
 	qpriv->r_tid_tail = HFI1_QP_WQE_INVALID;
 	qpriv->r_tid_ack = HFI1_QP_WQE_INVALID;
 	qpriv->r_tid_alloc = HFI1_QP_WQE_INVALID;
+	atomic_set(&qpriv->n_tid_requests, 0);
 	timer_setup(&qpriv->s_tid_timer, hfi1_tid_timeout, 0);
 	INIT_LIST_HEAD(&qpriv->tid_wait);
 
@@ -4314,3 +4316,213 @@ u32 hfi1_build_tid_rdma_write_ack(struct rvt_qp *qp, struct rvt_ack_entry *e,
 
 	return sizeof(ohdr->u.tid_rdma.ack) / sizeof(u32);
 }
+
+void hfi1_rc_rcv_tid_rdma_ack(struct hfi1_packet *packet)
+{
+	struct ib_other_headers *ohdr = packet->ohdr;
+	struct rvt_qp *qp = packet->qp;
+	struct hfi1_qp_priv *qpriv = qp->priv;
+	struct rvt_swqe *wqe;
+	struct tid_rdma_request *req;
+	struct tid_rdma_flow *flow;
+	u32 aeth, psn, req_psn, ack_psn, fspsn, resync_psn, ack_kpsn;
+	bool is_fecn;
+	unsigned long flags;
+	u16 fidx;
+
+	is_fecn = process_ecn(qp, packet);
+	psn = mask_psn(be32_to_cpu(ohdr->bth[2]));
+	aeth = be32_to_cpu(ohdr->u.tid_rdma.ack.aeth);
+	req_psn = mask_psn(be32_to_cpu(ohdr->u.tid_rdma.ack.verbs_psn));
+	resync_psn = mask_psn(be32_to_cpu(ohdr->u.tid_rdma.ack.tid_flow_psn));
+
+	spin_lock_irqsave(&qp->s_lock, flags);
+
+	/* If we are waiting for an ACK to RESYNC, drop any other packets */
+	if ((qp->s_flags & HFI1_S_WAIT_HALT) &&
+	    cmp_psn(psn, qpriv->s_resync_psn))
+		goto ack_op_err;
+
+	ack_psn = req_psn;
+	if (hfi1_tid_rdma_is_resync_psn(psn))
+		ack_kpsn = resync_psn;
+	else
+		ack_kpsn = psn;
+	if (aeth >> 29) {
+		ack_psn--;
+		ack_kpsn--;
+	}
+
+	wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
+
+	if (wqe->wr.opcode != IB_WR_TID_RDMA_WRITE)
+		goto ack_op_err;
+
+	req = wqe_to_tid_req(wqe);
+	flow = &req->flows[req->acked_tail];
+
+	/* Drop stale ACK/NAK */
+	if (cmp_psn(psn, full_flow_psn(flow, flow->flow_state.spsn)) < 0)
+		goto ack_op_err;
+
+	while (cmp_psn(ack_kpsn,
+		       full_flow_psn(flow, flow->flow_state.lpsn)) >= 0 &&
+	       req->ack_seg < req->cur_seg) {
+		req->ack_seg++;
+		/* advance acked segment pointer */
+		req->acked_tail = CIRC_NEXT(req->acked_tail, MAX_FLOWS);
+		req->r_last_acked = flow->flow_state.resp_ib_psn;
+		if (req->ack_seg == req->total_segs) {
+			req->state = TID_REQUEST_COMPLETE;
+			wqe = do_rc_completion(qp, wqe,
+					       to_iport(qp->ibqp.device,
+							qp->port_num));
+			atomic_dec(&qpriv->n_tid_requests);
+			if (qp->s_acked == qp->s_tail)
+				break;
+			if (wqe->wr.opcode != IB_WR_TID_RDMA_WRITE)
+				break;
+			req = wqe_to_tid_req(wqe);
+		}
+		flow = &req->flows[req->acked_tail];
+	}
+
+	switch (aeth >> 29) {
+	case 0:         /* ACK */
+		if (qpriv->s_flags & RVT_S_WAIT_ACK)
+			qpriv->s_flags &= ~RVT_S_WAIT_ACK;
+		if (!hfi1_tid_rdma_is_resync_psn(psn)) {
+			hfi1_schedule_send(qp);
+		} else {
+			u32 spsn, fpsn, last_acked, generation;
+			struct tid_rdma_request *rptr;
+
+			/* Allow new requests (see hfi1_make_tid_rdma_pkt) */
+			qp->s_flags &= ~HFI1_S_WAIT_HALT;
+			/*
+			 * Clear RVT_S_SEND_ONE flag in case that the TID RDMA
+			 * ACK is received after the TID retry timer is fired
+			 * again. In this case, do not send any more TID
+			 * RESYNC request or wait for any more TID ACK packet.
+			 */
+			qpriv->s_flags &= ~RVT_S_SEND_ONE;
+			hfi1_schedule_send(qp);
+
+			if ((qp->s_acked == qpriv->s_tid_tail &&
+			     req->ack_seg == req->total_segs) ||
+			    qp->s_acked == qp->s_tail) {
+				qpriv->s_state = TID_OP(WRITE_DATA_LAST);
+				goto done;
+			}
+
+			if (req->ack_seg == req->comp_seg) {
+				qpriv->s_state = TID_OP(WRITE_DATA);
+				goto done;
+			}
+
+			/*
+			 * The PSN to start with is the next PSN after the
+			 * RESYNC PSN.
+			 */
+			psn = mask_psn(psn + 1);
+			generation = psn >> HFI1_KDETH_BTH_SEQ_SHIFT;
+			spsn = 0;
+
+			/*
+			 * Update to the correct WQE when we get an ACK(RESYNC)
+			 * in the middle of a request.
+			 */
+			if (delta_psn(ack_psn, wqe->lpsn))
+				wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
+			req = wqe_to_tid_req(wqe);
+			flow = &req->flows[req->acked_tail];
+			/*
+			 * RESYNC re-numbers the PSN ranges of all remaining
+			 * segments. Also, PSN's start from 0 in the middle of a
+			 * segment and the first segment size is less than the
+			 * default number of packets. flow->resync_npkts is used
+			 * to track the number of packets from the start of the
+			 * real segment to the point of 0 PSN after the RESYNC
+			 * in order to later correctly rewind the SGE.
+			 */
+			fpsn = full_flow_psn(flow, flow->flow_state.spsn);
+			req->r_ack_psn = psn;
+			flow->resync_npkts +=
+				delta_psn(mask_psn(resync_psn + 1), fpsn);
+			/*
+			 * Renumber all packet sequence number ranges
+			 * based on the new generation.
+			 */
+			last_acked = qp->s_acked;
+			rptr = req;
+			while (1) {
+				/* start from last acked segment */
+				for (fidx = rptr->acked_tail;
+				     CIRC_CNT(rptr->setup_head, fidx,
+					      MAX_FLOWS);
+				     fidx = CIRC_NEXT(fidx, MAX_FLOWS)) {
+					u32 lpsn;
+					u32 gen;
+
+					flow = &rptr->flows[fidx];
+					gen = flow->flow_state.generation;
+					if (WARN_ON(gen == generation &&
+						    flow->flow_state.spsn !=
+						     spsn))
+						continue;
+					lpsn = flow->flow_state.lpsn;
+					lpsn = full_flow_psn(flow, lpsn);
+					flow->npkts =
+						delta_psn(lpsn,
+							  mask_psn(resync_psn)
+							  );
+					flow->flow_state.generation =
+						generation;
+					flow->flow_state.spsn = spsn;
+					flow->flow_state.lpsn =
+						flow->flow_state.spsn +
+						flow->npkts - 1;
+					flow->pkt = 0;
+					spsn += flow->npkts;
+					resync_psn += flow->npkts;
+				}
+				if (++last_acked == qpriv->s_tid_cur + 1)
+					break;
+				if (last_acked == qp->s_size)
+					last_acked = 0;
+				wqe = rvt_get_swqe_ptr(qp, last_acked);
+				rptr = wqe_to_tid_req(wqe);
+			}
+			req->cur_seg = req->ack_seg;
+			qpriv->s_tid_tail = qp->s_acked;
+			qpriv->s_state = TID_OP(WRITE_REQ);
+		}
+done:
+		qpriv->s_retry = qp->s_retry_cnt;
+		break;
+
+	case 3:         /* NAK */
+		switch ((aeth >> IB_AETH_CREDIT_SHIFT) &
+			IB_AETH_CREDIT_MASK) {
+		case 0: /* PSN sequence error */
+			flow = &req->flows[req->acked_tail];
+			fspsn = full_flow_psn(flow, flow->flow_state.spsn);
+			req->r_ack_psn = mask_psn(be32_to_cpu(ohdr->bth[2]));
+			req->cur_seg = req->ack_seg;
+			qpriv->s_tid_tail = qp->s_acked;
+			qpriv->s_state = TID_OP(WRITE_REQ);
+			qpriv->s_retry = qp->s_retry_cnt;
+			break;
+
+		default:
+			break;
+		}
+		break;
+
+	default:
+		break;
+	}
+
+ack_op_err:
+	spin_unlock_irqrestore(&qp->s_lock, flags);
+}
diff --git a/drivers/infiniband/hw/hfi1/tid_rdma.h b/drivers/infiniband/hw/hfi1/tid_rdma.h
index 89f5af6..499036e 100644
--- a/drivers/infiniband/hw/hfi1/tid_rdma.h
+++ b/drivers/infiniband/hw/hfi1/tid_rdma.h
@@ -101,6 +101,7 @@ struct tid_rdma_request {
 
 	u32 seg_len;
 	u32 total_len;
+	u32 r_ack_psn;          /* next expected ack PSN */
 	u32 r_flow_psn;         /* IB PSN of next segment start */
 	u32 r_last_acked;       /* IB PSN of last ACK'ed packet */
 	u32 s_next_psn;		/* IB PSN of next segment start for read */
@@ -285,4 +286,6 @@ u32 hfi1_build_tid_rdma_write_ack(struct rvt_qp *qp, struct rvt_ack_entry *e,
 				  struct ib_other_headers *ohdr, u16 iflow,
 				  u32 *bth1, u32 *bth2);
 
+void hfi1_rc_rcv_tid_rdma_ack(struct hfi1_packet *packet);
+
 #endif /* HFI1_TID_RDMA_H */
diff --git a/drivers/infiniband/hw/hfi1/trace_tid.h b/drivers/infiniband/hw/hfi1/trace_tid.h
index 51f5b0e..a45b525 100644
--- a/drivers/infiniband/hw/hfi1/trace_tid.h
+++ b/drivers/infiniband/hw/hfi1/trace_tid.h
@@ -52,7 +52,7 @@
 #define TID_READ_SENDER_PRN "[%s] qpn 0x%x newreq %u tid_r_reqs %u " \
 			    "tid_r_comp %u pending_tid_r_segs %u " \
 			    "s_flags 0x%x ps_flags 0x%x iow_flags 0x%lx " \
-			    "hw_flow_index %u generation 0x%x " \
+			    "s_state 0x%x hw_flow_index %u generation 0x%x " \
 			    "fpsn 0x%x flow_flags 0x%x"
 
 #define TID_REQ_PRN "[%s] qpn 0x%x newreq %u opcode 0x%x psn 0x%x lpsn 0x%x " \
@@ -844,6 +844,7 @@
 		__field(u32, s_flags)
 		__field(u32, ps_flags)
 		__field(unsigned long, iow_flags)
+		__field(u8, s_state)
 		__field(u32, hw_flow_index)
 		__field(u32, generation)
 		__field(u32, fpsn)
@@ -861,6 +862,7 @@
 		__entry->s_flags = qp->s_flags;
 		__entry->ps_flags = priv->s_flags;
 		__entry->iow_flags = priv->s_iowait.flags;
+		__entry->s_state = priv->s_state;
 		__entry->hw_flow_index = priv->flow_state.index;
 		__entry->generation = priv->flow_state.generation;
 		__entry->fpsn = priv->flow_state.psn;
@@ -877,6 +879,7 @@
 		__entry->s_flags,
 		__entry->ps_flags,
 		__entry->iow_flags,
+		__entry->s_state,
 		__entry->hw_flow_index,
 		__entry->generation,
 		__entry->fpsn,
diff --git a/drivers/infiniband/hw/hfi1/verbs.h b/drivers/infiniband/hw/hfi1/verbs.h
index 3a97a39..30e3f5a 100644
--- a/drivers/infiniband/hw/hfi1/verbs.h
+++ b/drivers/infiniband/hw/hfi1/verbs.h
@@ -170,9 +170,12 @@ struct hfi1_qp_priv {
 	struct tid_rdma_qp_params tid_rdma;
 	struct rvt_qp *owner;
 	u8 hdr_type; /* 9B or 16B */
+	atomic_t n_tid_requests;            /* # of sent TID RDMA requests */
 	unsigned long tid_timer_timeout_jiffies;
 
 	/* variables for the TID RDMA SE state machine */
+	u8 s_state;
+	u8 s_retry;
 	u8 rnr_nak_state;       /* RNR NAK state */
 	u8 s_nak_state;
 	u32 s_nak_psn;
@@ -197,6 +200,7 @@ struct hfi1_qp_priv {
 
 	u32 r_next_psn_kdeth;
 	u32 r_next_psn_kdeth_save;
+	u32 s_resync_psn;
 	u8 sync_pt;           /* Set when QP reaches sync point */
 	u8 resync;
 };
