diff options
Diffstat (limited to 'drivers/staging/rdma/hfi1/chip.c')
| -rw-r--r-- | drivers/staging/rdma/hfi1/chip.c | 32 |
1 files changed, 25 insertions, 7 deletions
diff --git a/drivers/staging/rdma/hfi1/chip.c b/drivers/staging/rdma/hfi1/chip.c index 13b92a3d3d8b..a67483e2ee96 100644 --- a/drivers/staging/rdma/hfi1/chip.c +++ b/drivers/staging/rdma/hfi1/chip.c @@ -8022,9 +8022,9 @@ static irqreturn_t sdma_interrupt(int irq, void *data) } /* - * Clear the receive interrupt, forcing the write and making sure - * we have data from the chip, pushing everything in front of it - * back to the host. + * Clear the receive interrupt. Use a read of the interrupt clear CSR + * to insure that the write completed. This does NOT guarantee that + * queued DMA writes to memory from the chip are pushed. */ static inline void clear_recv_intr(struct hfi1_ctxtdata *rcd) { @@ -8043,15 +8043,33 @@ void force_recv_intr(struct hfi1_ctxtdata *rcd) write_csr(rcd->dd, CCE_INT_FORCE + (8 * rcd->ireg), rcd->imask); } -/* return non-zero if a packet is present */ +/* + * Return non-zero if a packet is present. + * + * This routine is called when rechecking for packets after the RcvAvail + * interrupt has been cleared down. First, do a quick check of memory for + * a packet present. If not found, use an expensive CSR read of the context + * tail to determine the actual tail. The CSR read is necessary because there + * is no method to push pending DMAs to memory other than an interrupt and we + * are trying to determine if we need to force an interrupt. + */ static inline int check_packet_present(struct hfi1_ctxtdata *rcd) { + u32 tail; + int present; + if (!HFI1_CAP_IS_KSET(DMA_RTAIL)) - return (rcd->seq_cnt == + present = (rcd->seq_cnt == rhf_rcv_seq(rhf_to_cpu(get_rhf_addr(rcd)))); + else /* is RDMA rtail */ + present = (rcd->head != get_rcvhdrtail(rcd)); + + if (present) + return 1; - /* else is RDMA rtail */ - return (rcd->head != get_rcvhdrtail(rcd)); + /* fall back to a CSR read, correct indpendent of DMA_RTAIL */ + tail = (u32)read_uctxt_csr(rcd->dd, rcd->ctxt, RCV_HDR_TAIL); + return rcd->head != tail; } /* |