Embedded Software for SoC - Grupo de Mecatrônica EESC/USP

Introduction to Hardware Abstraction Layers for SOC 185
to validate the correct operation of reused SW in the HW architecture.
However, since the design of HW architecture may not yet be finished, the
HAL may not be designed, either.
In such a case, to enable the validation via simulation, we need a simulation
model of HAL. The simulation model needs to simulate the functionality
of HAL, i.e. context switch, interrupt processing, and processor I/O.
The simulation model of HAL can be used together with transaction level or
RTL models of on-chip bus and other HW modules. The simulation model
needs also to support timing simulation of upper layer SW. More details of
HAL simulation model can be found in [7].
5.2. Application-specific and automatic HAL design
When a (standard) HAL API is generic (to support most of HW architectures)
or platform-specific, it will provide for good portability to upper layer
SW. However, we can have a heavy HAL implementation (up to ~10 k lines
of code in the code library [3]). In such a case, the HAL implementation may
cause an overhead of system resource (in terms of code size) and performance
(execution delay of HAL).
To reduce such an overhead of HAL implementation, application-specific
HAL design is needed. In this case, HAL needs to be tailored to the upper
layer SW and HW architecture. To design such a HAL, we need to be able
to implement only the HAL API functions (and their dependent functions)
used by the upper layer SW. To the best of our knowledge, there has been no
research work to enable such an application-specific HAL design.
Conventional HAL design is manually done for a give board, e.g. using a
configuration tool such as Platform Builder for WindowCE. In the case of
SoC design, we perform design space exploration of HW architectures to
obtain optimal HW architecture(s). For each of HW architecture candidates,
HAL needs to be designed. Due to the large number of HW architecture
candidates, manual HAL design will be too time-consuming to enable fast