  We investigate an extension of the standard model (SM) with a singlet
fermionic dark matter (DM) particle which interacts with the SM sector through
a real singlet scalar. The presence of a new scalar provides the possibility of
generating a strongly first order phase transition needed for electroweak
baryogenesis. Taking into account the latest Higgs search results at the LHC
and the upper limits from the DM direct detection experiments especially that
from the LUX experiment, and combining the constraints from the LEP experiment
and the electroweak precision test, we explore the parameter space of this
model which can lead to the strongly first order phase transition. Both the
tree- and loop-level barriers are included in the calculations. We find that
the allowed mass of the second Higgs particle is in the range $\sim
30-350\hbox{ GeV}$. The allowed mixing angle $\alpha$ between the SM-like Higgs
particle and the second Higgs particle is constrained to $\alpha \lesssim
28^{\circ}$. The DM particle mass is predicted to be in the range $\sim
15-350\hbox{ GeV}$. The future XENON1T experiment can rule out a significant
proportion of the parameter space of this model. The constraint can be relaxed
only when the mass of the SM-like Higgs particle is degenerate with that of the
second Higgs particle, or the mixing angle is small enough.
