i.MX 8M Mini: about M4 wake up A53 through RPMsg

[yanghui]

Hi all:

I want to wake up the sleeping A53 with M4 via RPMsg,  but I found it failed . I need your help.

  I did an experiment with reference to the following post. Where is the RPMsg document for IMX8MM? 

  The result is successful implementation of RPMsg communication.

Based on the above experiments, I modified the experiment:

The practice is :

1. modify the firmware of M4 (rpmsg_lite_str_echo_rtos_imxcm4.bin). When M4 receives the RPMsg sent by A53, it will    delay 10s, then reply A53 message.

2. In this 10s process, if the command below is executed on the control terminal of A53:

      echo mem > /sys/power/state     [CMD 1]

At this time, A53 is not woken up, and M4 does not send an RPMsg reply message.

During the 10s process, if the command below is executed on the control terminal of A53:

 echo freeze > /sys/power/state   [CMD 2]

At this time, A53 is not woken up, and M4 can send an RPMsg reply message.

So my question is how to make M4 wake up A53 through RPMsg when A53 enters sleep mode via command([CMD 1] or [CMD 2]).

Thank you for your help.

[siva_prabhakara]

did u figure it out, how to do this?

[CarlosCasillas]

Hi,

You could take a look at the low-power suggestions from application note AN12195, available on the following link:

https://www.nxp.com/docs/en/application-note/AN12195.pdf

Hope this will be useful for you.
Best regards!
/Carlos
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[DavidC1]

I'm having a similar problem.  I have an RPMSG communication channel between the A53 and M4 cores on an i.MX8 mini.

If I put Linux to sleep, it seems to put the M4 to sleep as well (its background processing stops), so the code running there can't send an RPMSG packet, which should in theory wake the A53.

I downloaded application note AN12195, but it doesn't seem to have links to the test application or the Linux driver patches needed to make it work.  The document refers to several patch files, but doesn't seem to have any links I can follow in order to get those files.

Can someone here provide necessary links so I can get my M4 software to wake the A53?

[DavidC1]

I was able to find the code for AN1215.  Unfortunately, it is meant for an imx8mq SoC.

I tried porting the kernel changes over to the imx8mm, but it doesn't work.  With that change, my M4 doesn't run at all.

Is there an application note somewhere to show how to do this (sleep the A53 while not sleeping the M4) on an imx8mm SoC?