RDMA/mlx5: Return ECE data after modify QP

After users sets the ECE option, FW will return the agreed/supported bits
through an output structures of modify QP stages for regular QPs or
through create QP for the DCT.

Link: https://lore.kernel.org/r/20200526115440.205922-9-leon@kernel.org
Reviewed-by: Mark Zhang <markz@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/mlx5/qpc.c

@@ -341,6 +341,27 @@ static void mbox_free(struct mbox_info *mbox)
 	kfree(mbox->out);
 }
 
+static int get_ece_from_mbox(void *out, u16 opcode)
+{
+	int ece = 0;
+
+	switch (opcode) {
+	case MLX5_CMD_OP_INIT2RTR_QP:
+		ece = MLX5_GET(init2rtr_qp_out, out, ece);
+		break;
+	case MLX5_CMD_OP_RTR2RTS_QP:
+		ece = MLX5_GET(rtr2rts_qp_out, out, ece);
+		break;
+	case MLX5_CMD_OP_RTS2RTS_QP:
+		ece = MLX5_GET(rts2rts_qp_out, out, ece);
+		break;
+	default:
+		break;
+	}
+
+	return ece;
+}
+
 static int modify_qp_mbox_alloc(struct mlx5_core_dev *dev, u16 opcode, int qpn,
 				u32 opt_param_mask, void *qpc,
 				struct mbox_info *mbox, u16 uid, u32 ece)
@@ -438,6 +459,10 @@ int mlx5_core_qp_modify(struct mlx5_ib_dev *dev, u16 opcode, u32 opt_param_mask,
 
 	err = mlx5_cmd_exec(dev->mdev, mbox.in, mbox.inlen, mbox.out,
 			    mbox.outlen);
+
+	if (ece)
+		*ece = get_ece_from_mbox(mbox.out, opcode);
+
 	mbox_free(&mbox);
 	return err;
 }