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How to start linux after enabeling RPMsg in Devicetree

Question asked by Erik Friedel on May 30, 2018
Latest reply on Jul 27, 2020 by Nikhil Karale

Hi there


I have got an iMX7s on custom board with 512MB Ram. I successfully run the hello_world example and now I am trying to get the pingpong example to work. On the M4 side there are no problems. I can boot and it shows:

   RPMSG PingPong FreeRTOS RTOS API Demo...
   RPMSG Init as Remot

But on the Linux side there are a few problems:

If I don't enable rpmsg in the devicetree I can boot and load the pingpong module using modprobe imx_rpmsg_pingpong. Additionaly rpmsg is shown in /sys/bus and /sys/module/ . But nothing else happens.

If I set rpmsg in the devicetree to "okay" I just see this:

   Starting kernel ...

   Uncompressing Linux... done, booting the kernel.


Things that I've changed so far:

   - obviously modifying the DT

         - set rpmsg to "ok"

         - set usable memory

         / {

          memory {
          linux,usable-memory = <0x80000000 0x1ff00000>;



   - changing the vring in the Linux kernel in imx_rpmsg.c  from BFFF0000 --> 9FFF0000 (and BFFF8000 --> 9FFF8000)

   - changing the vring in FreeRTOS in platform_info.c the same way

   - RPMsg and Pingpong are enabled in the Kernel


Please help