net/mlx4_core: Add support for RoCE v2 entropy

In RoCE v2 we need to choose a source UDP port, we do so by using
entropy over the source and dest QPNs.
Signed-off-by: Moni Shoua <monis@mellanox.com>
Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/net/ethernet/mellanox/mlx4/qp.c

@@ -167,6 +167,12 @@ static int __mlx4_qp_modify(struct mlx4_dev *dev, struct mlx4_mtt *mtt,
 		context->log_page_size   = mtt->page_shift - MLX4_ICM_PAGE_SHIFT;
 	}
 
+	if ((cur_state == MLX4_QP_STATE_RTR) &&
+	    (new_state == MLX4_QP_STATE_RTS) &&
+	    dev->caps.flags2 & MLX4_DEV_CAP_FLAG2_ROCE_V1_V2)
+		context->roce_entropy =
+			cpu_to_be16(mlx4_qp_roce_entropy(dev, qp->qpn));
+
 	*(__be32 *) mailbox->buf = cpu_to_be32(optpar);
 	memcpy(mailbox->buf + 8, context, sizeof *context);
 
@@ -921,3 +927,23 @@ int mlx4_qp_to_ready(struct mlx4_dev *dev, struct mlx4_mtt *mtt,
 	return 0;
 }
 EXPORT_SYMBOL_GPL(mlx4_qp_to_ready);
+
+u16 mlx4_qp_roce_entropy(struct mlx4_dev *dev, u32 qpn)
+{
+	struct mlx4_qp_context context;
+	struct mlx4_qp qp;
+	int err;
+
+	qp.qpn = qpn;
+	err = mlx4_qp_query(dev, &qp, &context);
+	if (!err) {
+		u32 dest_qpn = be32_to_cpu(context.remote_qpn) & 0xffffff;
+		u16 folded_dst = folded_qp(dest_qpn);
+		u16 folded_src = folded_qp(qpn);
+
+		return (dest_qpn != qpn) ?
+			((folded_dst ^ folded_src) | 0xC000) :
+			folded_src | 0xC000;
+	}
+	return 0xdead;
+}

include/linux/mlx4/qp.h

@@ -204,7 +204,8 @@ struct mlx4_qp_context {
 	u32			reserved1;
 	__be32			next_send_psn;
 	__be32			cqn_send;
-	u32			reserved2[2];
+	__be16                  roce_entropy;
+	__be16                  reserved2[3];
 	__be32			last_acked_psn;
 	__be32			ssn;
 	__be32			params2;
@@ -487,4 +488,14 @@ static inline struct mlx4_qp *__mlx4_qp_lookup(struct mlx4_dev *dev, u32 qpn)
 
 void mlx4_qp_remove(struct mlx4_dev *dev, struct mlx4_qp *qp);
 
+static inline u16 folded_qp(u32 q)
+{
+	u16 res;
+
+	res = ((q & 0xff) ^ ((q & 0xff0000) >> 16)) | (q & 0xff00);
+	return res;
+}
+
+u16 mlx4_qp_roce_entropy(struct mlx4_dev *dev, u32 qpn);
+
 #endif /* MLX4_QP_H */