IB/mthca: Avoid alignment traps when writing doorbells

Architectures such as ia64 see alignment traps when doing a 64-bit 
read from __be32 doorbell[2] arrays to do doorbell writes in 
mthca_write64().  Fix this by just passing the two halves of the 
doorbell value into mthca_write64().  This actually improves the 
generated code by allowing the compiler to see what's going on better.
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/hw/mthca/mthca_cq.c

@@ -204,16 +204,11 @@ static void dump_cqe(struct mthca_dev *dev, void *cqe_ptr)
 static inline void update_cons_index(struct mthca_dev *dev, struct mthca_cq *cq,
 				     int incr)
 {
-	__be32 doorbell[2];
-
 	if (mthca_is_memfree(dev)) {
 		*cq->set_ci_db = cpu_to_be32(cq->cons_index);
 		wmb();
 	} else {
-		doorbell[0] = cpu_to_be32(MTHCA_TAVOR_CQ_DB_INC_CI | cq->cqn);
-		doorbell[1] = cpu_to_be32(incr - 1);
-
-		mthca_write64(doorbell,
+		mthca_write64(MTHCA_TAVOR_CQ_DB_INC_CI | cq->cqn, incr - 1,
 			      dev->kar + MTHCA_CQ_DOORBELL,
 			      MTHCA_GET_DOORBELL_LOCK(&dev->doorbell_lock));
 		/*
@@ -731,17 +726,12 @@ int mthca_poll_cq(struct ib_cq *ibcq, int num_entries,
 
 int mthca_tavor_arm_cq(struct ib_cq *cq, enum ib_cq_notify_flags flags)
 {
-	__be32 doorbell[2];
-
-	doorbell[0] = cpu_to_be32(((flags & IB_CQ_SOLICITED_MASK) ==
-				   IB_CQ_SOLICITED ?
+	u32 dbhi = ((flags & IB_CQ_SOLICITED_MASK) == IB_CQ_SOLICITED ?
 		    MTHCA_TAVOR_CQ_DB_REQ_NOT_SOL :
 		    MTHCA_TAVOR_CQ_DB_REQ_NOT) |
-				  to_mcq(cq)->cqn);
-	doorbell[1] = (__force __be32) 0xffffffff;
+		to_mcq(cq)->cqn;
 
-	mthca_write64(doorbell,
-		      to_mdev(cq->device)->kar + MTHCA_CQ_DOORBELL,
+	mthca_write64(dbhi, 0xffffffff, to_mdev(cq->device)->kar + MTHCA_CQ_DOORBELL,
 		      MTHCA_GET_DOORBELL_LOCK(&to_mdev(cq->device)->doorbell_lock));
 
 	return 0;
@@ -750,19 +740,16 @@ int mthca_tavor_arm_cq(struct ib_cq *cq, enum ib_cq_notify_flags flags)
 int mthca_arbel_arm_cq(struct ib_cq *ibcq, enum ib_cq_notify_flags flags)
 {
 	struct mthca_cq *cq = to_mcq(ibcq);
-	__be32 doorbell[2];
-	u32 sn;
-	__be32 ci;
-
-	sn = cq->arm_sn & 3;
-	ci = cpu_to_be32(cq->cons_index);
+	__be32 db_rec[2];
+	u32 dbhi;
+	u32 sn = cq->arm_sn & 3;
 
-	doorbell[0] = ci;
-	doorbell[1] = cpu_to_be32((cq->cqn << 8) | (2 << 5) | (sn << 3) |
+	db_rec[0] = cpu_to_be32(cq->cons_index);
+	db_rec[1] = cpu_to_be32((cq->cqn << 8) | (2 << 5) | (sn << 3) |
 				((flags & IB_CQ_SOLICITED_MASK) ==
 				 IB_CQ_SOLICITED ? 1 : 2));
 
-	mthca_write_db_rec(doorbell, cq->arm_db);
+	mthca_write_db_rec(db_rec, cq->arm_db);
 
 	/*
 	 * Make sure that the doorbell record in host memory is
@@ -770,14 +757,12 @@ int mthca_arbel_arm_cq(struct ib_cq *ibcq, enum ib_cq_notify_flags flags)
 	 */
 	wmb();
 
-	doorbell[0] = cpu_to_be32((sn << 28)                       |
+	dbhi = (sn << 28) |
 		((flags & IB_CQ_SOLICITED_MASK) == IB_CQ_SOLICITED ?
 		 MTHCA_ARBEL_CQ_DB_REQ_NOT_SOL :
-				   MTHCA_ARBEL_CQ_DB_REQ_NOT)      |
-				  cq->cqn);
-	doorbell[1] = ci;
+		 MTHCA_ARBEL_CQ_DB_REQ_NOT) | cq->cqn;
 
-	mthca_write64(doorbell,
+	mthca_write64(dbhi, cq->cons_index,
 		      to_mdev(ibcq->device)->kar + MTHCA_CQ_DOORBELL,
 		      MTHCA_GET_DOORBELL_LOCK(&to_mdev(ibcq->device)->doorbell_lock));
 

drivers/infiniband/hw/mthca/mthca_doorbell.h

@@ -58,10 +58,10 @@ static inline void mthca_write64_raw(__be64 val, void __iomem *dest)
 	__raw_writeq((__force u64) val, dest);
 }
 
-static inline void mthca_write64(__be32 val[2], void __iomem *dest,
+static inline void mthca_write64(u32 hi, u32 lo, void __iomem *dest,
 				 spinlock_t *doorbell_lock)
 {
-	__raw_writeq(*(u64 *) val, dest);
+	__raw_writeq((__force u64) cpu_to_be64((u64) hi << 32 | lo), dest);
 }
 
 static inline void mthca_write_db_rec(__be32 val[2], __be32 *db)
@@ -87,14 +87,17 @@ static inline void mthca_write64_raw(__be64 val, void __iomem *dest)
 	__raw_writel(((__force u32 *) &val)[1], dest + 4);
 }
 
-static inline void mthca_write64(__be32 val[2], void __iomem *dest,
+static inline void mthca_write64(u32 hi, u32 lo, void __iomem *dest,
 				 spinlock_t *doorbell_lock)
 {
 	unsigned long flags;
 
+	hi = (__force u32) cpu_to_be32(hi);
+	lo = (__force u32) cpu_to_be32(lo);
+
 	spin_lock_irqsave(doorbell_lock, flags);
-	__raw_writel((__force u32) val[0], dest);
-	__raw_writel((__force u32) val[1], dest + 4);
+	__raw_writel(hi, dest);
+	__raw_writel(lo, dest + 4);
 	spin_unlock_irqrestore(doorbell_lock, flags);
 }
 

drivers/infiniband/hw/mthca/mthca_eq.c

@@ -173,11 +173,6 @@ static inline u64 async_mask(struct mthca_dev *dev)
 
 static inline void tavor_set_eq_ci(struct mthca_dev *dev, struct mthca_eq *eq, u32 ci)
 {
-	__be32 doorbell[2];
-
-	doorbell[0] = cpu_to_be32(MTHCA_EQ_DB_SET_CI | eq->eqn);
-	doorbell[1] = cpu_to_be32(ci & (eq->nent - 1));
-
 	/*
 	 * This barrier makes sure that all updates to ownership bits
 	 * done by set_eqe_hw() hit memory before the consumer index
@@ -187,7 +182,7 @@ static inline void tavor_set_eq_ci(struct mthca_dev *dev, struct mthca_eq *eq, u
 	 * having set_eqe_hw() overwrite the owner field.
 	 */
 	wmb();
-	mthca_write64(doorbell,
+	mthca_write64(MTHCA_EQ_DB_SET_CI | eq->eqn, ci & (eq->nent - 1),
 		      dev->kar + MTHCA_EQ_DOORBELL,
 		      MTHCA_GET_DOORBELL_LOCK(&dev->doorbell_lock));
 }
@@ -212,12 +207,7 @@ static inline void set_eq_ci(struct mthca_dev *dev, struct mthca_eq *eq, u32 ci)
 
 static inline void tavor_eq_req_not(struct mthca_dev *dev, int eqn)
 {
-	__be32 doorbell[2];
-
-	doorbell[0] = cpu_to_be32(MTHCA_EQ_DB_REQ_NOT | eqn);
-	doorbell[1] = 0;
-
-	mthca_write64(doorbell,
+	mthca_write64(MTHCA_EQ_DB_REQ_NOT | eqn, 0,
 		      dev->kar + MTHCA_EQ_DOORBELL,
 		      MTHCA_GET_DOORBELL_LOCK(&dev->doorbell_lock));
 }
@@ -230,12 +220,7 @@ static inline void arbel_eq_req_not(struct mthca_dev *dev, u32 eqn_mask)
 static inline void disarm_cq(struct mthca_dev *dev, int eqn, int cqn)
 {
 	if (!mthca_is_memfree(dev)) {
-		__be32 doorbell[2];
-
-		doorbell[0] = cpu_to_be32(MTHCA_EQ_DB_DISARM_CQ | eqn);
-		doorbell[1] = cpu_to_be32(cqn);
-
-		mthca_write64(doorbell,
+		mthca_write64(MTHCA_EQ_DB_DISARM_CQ | eqn, cqn,
 			      dev->kar + MTHCA_EQ_DOORBELL,
 			      MTHCA_GET_DOORBELL_LOCK(&dev->doorbell_lock));
 	}

drivers/infiniband/hw/mthca/mthca_qp.c

@@ -1799,15 +1799,11 @@ int mthca_tavor_post_send(struct ib_qp *ibqp, struct ib_send_wr *wr,
 
 out:
 	if (likely(nreq)) {
-		__be32 doorbell[2];
-
-		doorbell[0] = cpu_to_be32(((qp->sq.next_ind << qp->sq.wqe_shift) +
-					   qp->send_wqe_offset) | f0 | op0);
-		doorbell[1] = cpu_to_be32((qp->qpn << 8) | size0);
-
 		wmb();
 
-		mthca_write64(doorbell,
+		mthca_write64(((qp->sq.next_ind << qp->sq.wqe_shift) +
+			       qp->send_wqe_offset) | f0 | op0,
+			      (qp->qpn << 8) | size0,
 			      dev->kar + MTHCA_SEND_DOORBELL,
 			      MTHCA_GET_DOORBELL_LOCK(&dev->doorbell_lock));
 		/*
@@ -1829,7 +1825,6 @@ int mthca_tavor_post_receive(struct ib_qp *ibqp, struct ib_recv_wr *wr,
 {
 	struct mthca_dev *dev = to_mdev(ibqp->device);
 	struct mthca_qp *qp = to_mqp(ibqp);
-	__be32 doorbell[2];
 	unsigned long flags;
 	int err = 0;
 	int nreq;
@@ -1907,13 +1902,10 @@ int mthca_tavor_post_receive(struct ib_qp *ibqp, struct ib_recv_wr *wr,
 		if (unlikely(nreq == MTHCA_TAVOR_MAX_WQES_PER_RECV_DB)) {
 			nreq = 0;
 
-			doorbell[0] = cpu_to_be32((qp->rq.next_ind << qp->rq.wqe_shift) | size0);
-			doorbell[1] = cpu_to_be32(qp->qpn << 8);
-
 			wmb();
 
-			mthca_write64(doorbell,
-				      dev->kar + MTHCA_RECEIVE_DOORBELL,
+			mthca_write64((qp->rq.next_ind << qp->rq.wqe_shift) | size0,
+				      qp->qpn << 8, dev->kar + MTHCA_RECEIVE_DOORBELL,
 				      MTHCA_GET_DOORBELL_LOCK(&dev->doorbell_lock));
 
 			qp->rq.next_ind = ind;
@@ -1923,13 +1915,10 @@ int mthca_tavor_post_receive(struct ib_qp *ibqp, struct ib_recv_wr *wr,
 
 out:
 	if (likely(nreq)) {
-		doorbell[0] = cpu_to_be32((qp->rq.next_ind << qp->rq.wqe_shift) | size0);
-		doorbell[1] = cpu_to_be32((qp->qpn << 8) | nreq);
-
 		wmb();
 
-		mthca_write64(doorbell,
-			      dev->kar + MTHCA_RECEIVE_DOORBELL,
+		mthca_write64((qp->rq.next_ind << qp->rq.wqe_shift) | size0,
+			      qp->qpn << 8 | nreq, dev->kar + MTHCA_RECEIVE_DOORBELL,
 			      MTHCA_GET_DOORBELL_LOCK(&dev->doorbell_lock));
 	}
 
@@ -1951,7 +1940,7 @@ int mthca_arbel_post_send(struct ib_qp *ibqp, struct ib_send_wr *wr,
 {
 	struct mthca_dev *dev = to_mdev(ibqp->device);
 	struct mthca_qp *qp = to_mqp(ibqp);
-	__be32 doorbell[2];
+	u32 dbhi;
 	void *wqe;
 	void *prev_wqe;
 	unsigned long flags;
@@ -1981,10 +1970,8 @@ int mthca_arbel_post_send(struct ib_qp *ibqp, struct ib_send_wr *wr,
 		if (unlikely(nreq == MTHCA_ARBEL_MAX_WQES_PER_SEND_DB)) {
 			nreq = 0;
 
-			doorbell[0] = cpu_to_be32((MTHCA_ARBEL_MAX_WQES_PER_SEND_DB << 24) |
-						  ((qp->sq.head & 0xffff) << 8) |
-						  f0 | op0);
-			doorbell[1] = cpu_to_be32((qp->qpn << 8) | size0);
+			dbhi = (MTHCA_ARBEL_MAX_WQES_PER_SEND_DB << 24) |
+				((qp->sq.head & 0xffff) << 8) | f0 | op0;
 
 			qp->sq.head += MTHCA_ARBEL_MAX_WQES_PER_SEND_DB;
 
@@ -2000,7 +1987,8 @@ int mthca_arbel_post_send(struct ib_qp *ibqp, struct ib_send_wr *wr,
 			 * write MMIO send doorbell.
 			 */
 			wmb();
-			mthca_write64(doorbell,
+
+			mthca_write64(dbhi, (qp->qpn << 8) | size0,
 				      dev->kar + MTHCA_SEND_DOORBELL,
 				      MTHCA_GET_DOORBELL_LOCK(&dev->doorbell_lock));
 		}
@@ -2154,10 +2142,7 @@ int mthca_arbel_post_send(struct ib_qp *ibqp, struct ib_send_wr *wr,
 
 out:
 	if (likely(nreq)) {
-		doorbell[0] = cpu_to_be32((nreq << 24)                  |
-					  ((qp->sq.head & 0xffff) << 8) |
-					  f0 | op0);
-		doorbell[1] = cpu_to_be32((qp->qpn << 8) | size0);
+		dbhi = (nreq << 24) | ((qp->sq.head & 0xffff) << 8) | f0 | op0;
 
 		qp->sq.head += nreq;
 
@@ -2173,8 +2158,8 @@ int mthca_arbel_post_send(struct ib_qp *ibqp, struct ib_send_wr *wr,
 		 * write MMIO send doorbell.
 		 */
 		wmb();
-		mthca_write64(doorbell,
-			      dev->kar + MTHCA_SEND_DOORBELL,
+
+		mthca_write64(dbhi, (qp->qpn << 8) | size0, dev->kar + MTHCA_SEND_DOORBELL,
 			      MTHCA_GET_DOORBELL_LOCK(&dev->doorbell_lock));
 	}
 

drivers/infiniband/hw/mthca/mthca_srq.c

@@ -491,7 +491,6 @@ int mthca_tavor_post_srq_recv(struct ib_srq *ibsrq, struct ib_recv_wr *wr,
 {
 	struct mthca_dev *dev = to_mdev(ibsrq->device);
 	struct mthca_srq *srq = to_msrq(ibsrq);
-	__be32 doorbell[2];
 	unsigned long flags;
 	int err = 0;
 	int first_ind;
@@ -563,16 +562,13 @@ int mthca_tavor_post_srq_recv(struct ib_srq *ibsrq, struct ib_recv_wr *wr,
 		if (unlikely(nreq == MTHCA_TAVOR_MAX_WQES_PER_RECV_DB)) {
 			nreq = 0;
 
-			doorbell[0] = cpu_to_be32(first_ind << srq->wqe_shift);
-			doorbell[1] = cpu_to_be32(srq->srqn << 8);
-
 			/*
 			 * Make sure that descriptors are written
 			 * before doorbell is rung.
 			 */
 			wmb();
 
-			mthca_write64(doorbell,
+			mthca_write64(first_ind << srq->wqe_shift, srq->srqn << 8,
 				      dev->kar + MTHCA_RECEIVE_DOORBELL,
 				      MTHCA_GET_DOORBELL_LOCK(&dev->doorbell_lock));
 
@@ -581,16 +577,13 @@ int mthca_tavor_post_srq_recv(struct ib_srq *ibsrq, struct ib_recv_wr *wr,
 	}
 
 	if (likely(nreq)) {
-		doorbell[0] = cpu_to_be32(first_ind << srq->wqe_shift);
-		doorbell[1] = cpu_to_be32((srq->srqn << 8) | nreq);
-
 		/*
 		 * Make sure that descriptors are written before
 		 * doorbell is rung.
 		 */
 		wmb();
 
-		mthca_write64(doorbell,
+		mthca_write64(first_ind << srq->wqe_shift, (srq->srqn << 8) | nreq,
 			      dev->kar + MTHCA_RECEIVE_DOORBELL,
 			      MTHCA_GET_DOORBELL_LOCK(&dev->doorbell_lock));
 	}