Electronic design automation (EDA) has enabled the integrated circuit industry to sustain exponentially increasing product complexity growth until today, while maintaining consistent product development timeline and costs. We argue that the success of EDA-based design relies on the application of four interrelated principles: 1) separation of concerns implying a decomposition of a design flow into steps, each step dealing with specific aspects, namely user requirements, functional design, and implementation; 2) component-based design enabling the reasoned construction of complex systems as the composition of components; 3) semantic coherency meaning that descriptions used in successive design steps are semantically related through adequate semantic mappings; this implies, in particular, that the formalisms used at each design step are rooted in well-defined semantics; and 4) correctness by construction meaning that it is possible to guarantee essential properties of the designed system incrementally and compositionally along the design process. The paper discusses to what extent the EDA paradigm can be adapted to general mixed hardware/software (HW/SW) systems design through the application of these principles. It presents an overview of the problems raised by the rigorous system design of mixed HW/SW systems. Then, it presents a unified abstract framework for addressing these problems by identifying main research avenues.