I need to use M4 core to handle SPI communication with a onboard device. Up to now I have read some docs about how to use M4 with the A53 core whith Linux OS. There some tips I have got, but I'm not sure if it is correct. Will some one figure it out?
1, M4 program is build with MCUXpresso SDK, the output bin image is flashed to emmc sectors, which is packaged with u-boot image, dtb, and hdmi firmwares. Adding enviroment variable to U-boot will boot up M4 core and A53 parallelly.
2, M4 can share all the peripherals with A53. For example in schematic I connect SPI device to ECSPIx founded in IMX8MDQLQRM.pdf, without any changes I can use ECSPIx in M4 program? If it is so, what happens if both side, M4 and A53, access the same ECSPIx?
3, M4 and A53 use RPMSG to share infos?
Also there some question I want to ask:
1, Can M4 image be loaded from Linux kernel? I mean use some tool to load a firmware to M4 instead of flashing it to EMMC. Also, can Linux reset M4 core?