Using the quasielastic light scattering we have studied the order parameter dynamics close to the SmA-SmC* phase transition in thin cells of ferroelectric liquid crystals, with planar boundary conditions. As a result of confinement, the bulk soft mode splits into two modes, whereas from the thickness dependence of the relaxation rate of the phase mode we measure the diffusion coefficients. The appearance of the chevron structure is manifested in the temperature dependence of the relaxation rate of the phase mode.