{net, IB}/mlx4: Initialize CQ buffers in the driver when possible

Perform CQ initialization in the driver when the capability is supported
by the FW.  When passing the CQ to HW indicate that the CQ buffer has
been pre-initialized.

Doing so decreases CQ creation time.  Testing on P8 showed a single 2048
entry CQ creation time was reduced from ~395us to ~170us, which is
2.3x faster.

Signed-off-by: Daniel Jurgens <danielj@mellanox.com>
Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 71 insertions, 5 deletions

diff --git a/drivers/net/ethernet/mellanox/mlx4/cq.c b/drivers/net/ethernet/mellanox/mlx4/cq.c
index d8e9a323122e..db909b6069b5 100644
--- a/drivers/net/ethernet/mellanox/mlx4/cq.c
+++ b/drivers/net/ethernet/mellanox/mlx4/cq.c
@@ -144,9 +144,9 @@ void mlx4_cq_event(struct mlx4_dev *dev, u32 cqn, int event_type)
 }
 
 static int mlx4_SW2HW_CQ(struct mlx4_dev *dev, struct mlx4_cmd_mailbox *mailbox,
-			 int cq_num)
+			 int cq_num, u8 opmod)
 {
-	return mlx4_cmd(dev, mailbox->dma, cq_num, 0,
+	return mlx4_cmd(dev, mailbox->dma, cq_num, opmod,
 			MLX4_CMD_SW2HW_CQ, MLX4_CMD_TIME_CLASS_A,
 			MLX4_CMD_WRAPPED);
 }
@@ -287,11 +287,61 @@ static void mlx4_cq_free_icm(struct mlx4_dev *dev, int cqn)
 		__mlx4_cq_free_icm(dev, cqn);
 }
 
+static int mlx4_init_user_cqes(void *buf, int entries, int cqe_size)
+{
+	int entries_per_copy = PAGE_SIZE / cqe_size;
+	void *init_ents;
+	int err = 0;
+	int i;
+
+	init_ents = kmalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!init_ents)
+		return -ENOMEM;
+
+	/* Populate a list of CQ entries to reduce the number of
+	 * copy_to_user calls. 0xcc is the initialization value
+	 * required by the FW.
+	 */
+	memset(init_ents, 0xcc, PAGE_SIZE);
+
+	if (entries_per_copy < entries) {
+		for (i = 0; i < entries / entries_per_copy; i++) {
+			err = copy_to_user(buf, init_ents, PAGE_SIZE);
+			if (err)
+				goto out;
+
+			buf += PAGE_SIZE;
+		}
+	} else {
+		err = copy_to_user(buf, init_ents, entries * cqe_size);
+	}
+
+out:
+	kfree(init_ents);
+
+	return err;
+}
+
+static void mlx4_init_kernel_cqes(struct mlx4_buf *buf,
+				  int entries,
+				  int cqe_size)
+{
+	int i;
+
+	if (buf->nbufs == 1)
+		memset(buf->direct.buf, 0xcc, entries * cqe_size);
+	else
+		for (i = 0; i < buf->npages; i++)
+			memset(buf->page_list[i].buf, 0xcc,
+			       1UL << buf->page_shift);
+}
+
 int mlx4_cq_alloc(struct mlx4_dev *dev, int nent,
 		  struct mlx4_mtt *mtt, struct mlx4_uar *uar, u64 db_rec,
 		  struct mlx4_cq *cq, unsigned vector, int collapsed,
-		  int timestamp_en)
+		  int timestamp_en, void *buf_addr, bool user_cq)
 {
+	bool sw_cq_init = dev->caps.flags2 & MLX4_DEV_CAP_FLAG2_SW_CQ_INIT;
 	struct mlx4_priv *priv = mlx4_priv(dev);
 	struct mlx4_cq_table *cq_table = &priv->cq_table;
 	struct mlx4_cmd_mailbox *mailbox;
@@ -336,7 +386,20 @@ int mlx4_cq_alloc(struct mlx4_dev *dev, int nent,
 	cq_context->mtt_base_addr_l = cpu_to_be32(mtt_addr & 0xffffffff);
 	cq_context->db_rec_addr     = cpu_to_be64(db_rec);
 
-	err = mlx4_SW2HW_CQ(dev, mailbox, cq->cqn);
+	if (sw_cq_init) {
+		if (user_cq) {
+			err = mlx4_init_user_cqes(buf_addr, nent,
+						  dev->caps.cqe_size);
+			if (err)
+				sw_cq_init = false;
+		} else {
+			mlx4_init_kernel_cqes(buf_addr, nent,
+					      dev->caps.cqe_size);
+		}
+	}
+
+	err = mlx4_SW2HW_CQ(dev, mailbox, cq->cqn, sw_cq_init);
+
 	mlx4_free_cmd_mailbox(dev, mailbox);
 	if (err)
 		goto err_radix;
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_cq.c b/drivers/net/ethernet/mellanox/mlx4/en_cq.c
index 1e487acb4667..062a88fcc5d6 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_cq.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_cq.c
@@ -143,7 +143,7 @@ int mlx4_en_activate_cq(struct mlx4_en_priv *priv, struct mlx4_en_cq *cq,
 	cq->mcq.usage = MLX4_RES_USAGE_DRIVER;
 	err = mlx4_cq_alloc(mdev->dev, cq->size, &cq->wqres.mtt,
 			    &mdev->priv_uar, cq->wqres.db.dma, &cq->mcq,
-			    cq->vector, 0, timestamp_en);
+			    cq->vector, 0, timestamp_en, &cq->wqres.buf, false);
 	if (err)
 		goto free_eq;
 
diff --git a/drivers/net/ethernet/mellanox/mlx4/fw.c b/drivers/net/ethernet/mellanox/mlx4/fw.c
index babcfd9c0571..7df728f1e5b5 100644
--- a/drivers/net/ethernet/mellanox/mlx4/fw.c
+++ b/drivers/net/ethernet/mellanox/mlx4/fw.c
@@ -166,6 +166,7 @@ static void dump_dev_cap_flags2(struct mlx4_dev *dev, u64 flags)
 		[37] = "sl to vl mapping table change event support",
 		[38] = "user MAC support",
 		[39] = "Report driver version to FW support",
+		[40] = "SW CQ initialization support",
 	};
 	int i;
 
@@ -1098,6 +1099,8 @@ int mlx4_QUERY_DEV_CAP(struct mlx4_dev *dev, struct mlx4_dev_cap *dev_cap)
 		dev_cap->flags2 |= MLX4_DEV_CAP_FLAG2_FSM;
 	if (field32 & (1 << 21))
 		dev_cap->flags2 |= MLX4_DEV_CAP_FLAG2_80_VFS;
+	if (field32 & (1 << 23))
+		dev_cap->flags2 |= MLX4_DEV_CAP_FLAG2_SW_CQ_INIT;
 
 	for (i = 1; i <= dev_cap->num_ports; i++) {
 		err = mlx4_QUERY_PORT(dev, i, dev_cap->port_cap + i);