Dynamic reconfiguration of hardware resources is increasingly used in applications as a way to increase performances, resources integration or energy efficiency. As this evolution induces a change of the application execution paradigm, various tools have been set up to develop and manage these applications. But most do not allow direct re-use of legacy code, needing adaptation to match the provided environment. Moreover, partial reconfiguration is only at its early stages, and lacks easy ways of handling. We propose a design methodology and a runtime environment bringing fast integration of legacy hardware accelerators for partial and dynamic reconfigurable hardware architectures. Thanks to it, applications making use of dynamic hardware can be run directly on an Embedded Linux without noticing the reconfiguration flow. Moreover, our design methodology allows providing various implementations of a computation kernel, including both hardware and software ones. The implementation can then be chosen at execution time depending on available resources. In this article, we introduce the generic IP interface description making the re-use process possible. Furthermore, we present the results of a sample application running on our platform using software and hardware implementations. For hardware implementations, we obtain reconfiguration overhead as low as 0.16\% of the total kernel execution time.