Thanks for the interest. The D-CAN controller would be useful. It is found on
TI TMS570LC4357 and TMS570LS3137 chips which are supported by RTEMS (see TMS570 BSP in RTEMS User Manual and our student related thesis, unfortunately in Czech language only). There is even our complex time triggered support for it available (again thesis, fortunately in English). I have some reference source for that. The controller is found in its HECC (TI High End CAN Controller) variant on many other TI chips like BegleBoneBlack (AM335x, BSP) and there has been attempt to implement it in the GSoC frame in the past but the setup of CAN bus core infrastructure failed at that time. The CAN core developed by Michal Lenc (see thesis) is mature and integrated now and adding the chip support based on the other chips examples should be feasible for GSoC.
Do you have some above hardware with D-CAN supported by RTEMS? I have all three BBB, TMS570LC4357 and TMS570LS3137 but I have not tested RTEMS on them for long time so some cooperation and need for fixes could be required during bring-up.
Disadvantage is that D-CAN does not have support in QEMU yet. Qemu includes support only for CTU CAN FD, SJA1000, Xilinx on UltraScale and above and FlexCAN in review/integration stage.
But I agree that BBB and TMS570 are targets fitting well RTEMS application area so it would worth to be included.
I and Michal Lenc can mentor this projects.