[PATCH v2 for-next 2/2] RDMA/hns: Fix alignment problem of the doorbell

[Yixian Liu <liuyixian-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>]

The array defined for doorbell is not guaranteed to be 64 bit
aligned while we write it to the hardware with 64 bit
alignment required.

This patch fixes this problem by defining a union for doorbell
to make sure it 64 bit alignment.

v2:
1. Consider with Leon's comments, make sure it is 64 bit
   alignment by assigning the expected value to the u64
   member of the union type, i.e., assign doorbell array
   to doorbell64.

Signed-off-by: Yixian Liu <liuyixian-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
Signed-off-by: Lijun Ou <oulijun-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
Signed-off-by: Wei Hu (Xavier) <xavier.huwei-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
---
 drivers/infiniband/hw/hns/hns_roce_device.h |  5 +++++
 drivers/infiniband/hw/hns/hns_roce_hw_v2.c  | 18 ++++++++++--------
 2 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/drivers/infiniband/hw/hns/hns_roce_device.h b/drivers/infiniband/hw/hns/hns_roce_device.h
index dde5178..de0534f 100644
--- a/drivers/infiniband/hw/hns/hns_roce_device.h
+++ b/drivers/infiniband/hw/hns/hns_roce_device.h
@@ -569,6 +569,11 @@ struct hns_roce_eq_table {
 	void __iomem		**eqc_base; /* only for hw v1 */
 };
 
+union hns_roce_db64 {
+	u64	doorbell64;
+	u32	doorbell[2];
+};
+
 struct hns_roce_caps {
 	u8		num_ports;
 	int		gid_table_len[HNS_ROCE_MAX_PORTS];
diff --git a/drivers/infiniband/hw/hns/hns_roce_hw_v2.c b/drivers/infiniband/hw/hns/hns_roce_hw_v2.c
index 7f393f6..4681220 100644
--- a/drivers/infiniband/hw/hns/hns_roce_hw_v2.c
+++ b/drivers/infiniband/hw/hns/hns_roce_hw_v2.c
@@ -3172,33 +3172,35 @@ static int hns_roce_v2_modify_cq(struct ib_cq *cq, u16 cq_count, u16 cq_period)
 
 static void set_eq_cons_index_v2(struct hns_roce_eq *eq)
 {
-	u32 doorbell[2];
+	union hns_roce_db64 db;
 
-	doorbell[0] = 0;
-	doorbell[1] = 0;
+	db.doorbell[0] = 0;
+	db.doorbell[1] = 0;
 
 	if (eq->type_flag == HNS_ROCE_AEQ) {
-		roce_set_field(doorbell[0], HNS_ROCE_V2_EQ_DB_CMD_M,
+		roce_set_field(db.doorbell[0], HNS_ROCE_V2_EQ_DB_CMD_M,
 			       HNS_ROCE_V2_EQ_DB_CMD_S,
 			       eq->arm_st == HNS_ROCE_V2_EQ_ALWAYS_ARMED ?
 			       HNS_ROCE_EQ_DB_CMD_AEQ :
 			       HNS_ROCE_EQ_DB_CMD_AEQ_ARMED);
 	} else {
-		roce_set_field(doorbell[0], HNS_ROCE_V2_EQ_DB_TAG_M,
+		roce_set_field(db.doorbell[0], HNS_ROCE_V2_EQ_DB_TAG_M,
 			       HNS_ROCE_V2_EQ_DB_TAG_S, eq->eqn);
 
-		roce_set_field(doorbell[0], HNS_ROCE_V2_EQ_DB_CMD_M,
+		roce_set_field(db.doorbell[0], HNS_ROCE_V2_EQ_DB_CMD_M,
 			       HNS_ROCE_V2_EQ_DB_CMD_S,
 			       eq->arm_st == HNS_ROCE_V2_EQ_ALWAYS_ARMED ?
 			       HNS_ROCE_EQ_DB_CMD_CEQ :
 			       HNS_ROCE_EQ_DB_CMD_CEQ_ARMED);
 	}
 
-	roce_set_field(doorbell[1], HNS_ROCE_V2_EQ_DB_PARA_M,
+	roce_set_field(db.doorbell[1], HNS_ROCE_V2_EQ_DB_PARA_M,
 		       HNS_ROCE_V2_EQ_DB_PARA_S,
 		       (eq->cons_index & HNS_ROCE_V2_CONS_IDX_M));
 
-	hns_roce_write64_k(doorbell, eq->doorbell);
+	db.doorbell64 = ((u64) db.doorbell[0] << 32) | db.doorbell[1];
+
+	hns_roce_write64_k(db.doorbell, eq->doorbell);
 
 	/* Make sure we update the consumer index of EQ before
 	 * accessing it later
-- 
1.9.1

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