When having multiple DMA cores sharing the same constraint file Vivado
seems to apply the constraints from the first core to all the other cores
when re-running synthesis and implementation from within the Vivado GUI.
This causes wrong timing constraints if the DMA cores have different
configurations. To avoid this issue use a TTCL template that generates a
custom constraint file for each DMA core instance.
This also allows us to drop the asynchronous clock detection hack from the
constraint file and move it to the template and only generate the CDC
constraints if the clock domains are asynchronous.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Lars-Peter Clausen