RPMSG on iMX8's M7 without an RTOS?

[EdSutter]

I'm working with an iMX8MPlus.

I've built/ran the rpmsg_lite_str_echo_rtos example and managed to communicate with it from Linux; however, I don't want FreeRTOS in the way.  Are any examples for RPMSG available that don't use FreeRTOS?

[btessele]

The rpmsg-lite has a bm implementation, so you could build your application and point it to use the bm instead of the freertos. The problem is that the rpmsg-lite relies on the env_*_queue api which is implemented only for freertos. That said, you could use the same example but change your CMakeLists.txt to include the rpmsg-lite bm environment. In my case, I added two .cmake files

middleware/multicore/middleware_multicore_rpmsg_lite_bm_MIMX8ML8.cmake
middleware/multicore/middleware_multicore_rpmsg_lite_imx8mp_m7_bm_MIMX8ML8.cmake

to build the bm environment. Then you also need to change your project's config.cmake, remove the rpmsg_lite_freertos config and add the bm:

set(CONFIG_USE_middleware_multicore_rpmsg_lite_bm_MIMX8ML8 true)

Lastly, the flags.cmake contains the RTOS flag that should be removed:

-DSDK_OS_FREE_RTOS \

With some fixes here and there you will be able to compile, but then it will lack the queue implementation which I pointed before. Here you can find more info: https://community.toradex.com/t/bare-metal-rpmsg-on-verdin/18035/3 

[EdSutter]

Hi @btessele,

Thanks for responding!  After I got the "we don't support that" response from NXP folk I did essentially what you suggested... I rebuilt with the bm_*** file, finding that there was no queue API, so I just wrote a simple circular buffer in C and inserted that into the bm_*** file.

Not sure why NXP didn't provide that, but it was simple enough to add..

Regards,

Ed 

[AldoG · Accepted solution]

Hello,

No, we do not have examples for RPMSG without FreeRTOS.

Best regards,
Aldo.