A model of (constant-roll) inflation, where the second slow-roll parameter η remains constant, has been investigated. In this case the equation for the Hubble rate has an analytical solution, which describes four possible scenarios of inflation. The corresponding observational parameters n_s and r are determined and their values are compared with observational data. The scenario when inflation is driven by a tachyon field in the framework of Randall-Sundrum II cosmology is considered and compared with the “standard“ one. We reconstruct the potential which correspond to the model with constant η, and discuss an attractor behaviour in the model.