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IB/mthca: Avoid alignment traps when writing doorbells
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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>
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Roland Dreier committed Oct 16, 2007
1 parent 744ea92 commit ab8403c
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Showing 5 changed files with 47 additions and 96 deletions.
53 changes: 19 additions & 34 deletions drivers/infiniband/hw/mthca/mthca_cq.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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));
/*
Expand Down Expand Up @@ -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];
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[0] = cpu_to_be32(((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;

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;
Expand All @@ -750,34 +740,29 @@ 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) |
((flags & IB_CQ_SOLICITED_MASK) ==
IB_CQ_SOLICITED ? 1 : 2));
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
* written before ringing the doorbell via PCI MMIO.
*/
wmb();

doorbell[0] = cpu_to_be32((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;
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;

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));

Expand Down
13 changes: 8 additions & 5 deletions drivers/infiniband/hw/mthca/mthca_doorbell.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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)
Expand All @@ -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);
}

Expand Down
21 changes: 3 additions & 18 deletions drivers/infiniband/hw/mthca/mthca_eq.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand All @@ -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));
}
Expand All @@ -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));
}
Expand All @@ -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));
}
Expand Down
45 changes: 15 additions & 30 deletions drivers/infiniband/hw/mthca/mthca_qp.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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));
/*
Expand All @@ -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;
Expand Down Expand Up @@ -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;
Expand All @@ -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));
}

Expand All @@ -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;
Expand Down Expand Up @@ -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;

Expand All @@ -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));
}
Expand Down Expand Up @@ -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;

Expand All @@ -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));
}

Expand Down
11 changes: 2 additions & 9 deletions drivers/infiniband/hw/mthca/mthca_srq.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down Expand Up @@ -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));

Expand All @@ -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));
}
Expand Down

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