Missing /dev/ttyRpmsg entry in cortex(M4&A7) communication

[s_shrishail]

Hi Guys,

I am doing an activity regarding cortex communication between M4 and A7 in Imx7 sabre board.

* For this i have built sample rpmsg_str_echo application and loaded using fatload command in minicom

* I have build linux kernel image  by enabling following entities in menuconfig

1.IMX Rpmsg pingpong driver

2. IMX Rpmsg tty driver

using yocto build after flashing the images it is working fine but i am not able to find an entry in /dev folder ie /dev/ttyRPMSG

* Without /dev/ttyRPMSG entry i cant communicate to m4 cortex

Please help me with the issue

[terry_lv]

Hi,

  Are you running a M core image at M core side?

  The imx_rpmsg_tty.ko need to co-work with a rpmsg_lite_str_echo_rtos image at M core side.

  Thanks!

Regards

Terry

[s_shrishail]

No i am loading M4 image @uboot console on A7 terminal

There is no handshake mesage on M4 treminal

and There is no /dev/ttyRPMSG entry. communication channel between M4 and A7 is not getting created for communication. please help me with this issue and If possible try to give steps if anything missing on steps of my previous post

This one tries with linux version 4.9 and 4.14. Still the same issue

[terry_lv]

Yes, without rpmsg_lite_str_echo_rtos image running in M4, there's no handshake mesage between A7 and M4.

As iMX7D SDK is not updated anymore, I'm afraid you have to port rpmsg_lite_str_echo_rtos example from iMX7ULP SDK package.

User can download iMX7ULP SDK package from:

https://mcuxpresso.nxp.com/en/welcome

Thanks!

[s_shrishail]

Hi,

Freertos rpmsg image has been loaded to M4 cortex I am able to see following logs

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

After inserting imx_rpmsg_pingpong  and imx_rpmsg_tty module on A7 side needs to get following handshake log on M4 console and communication has to start like below that is not happening

Name service handshake is done, M4 has setup a rpmsg channel [1 ---> 1024]

Get Data From Master Side:0

Get Data From Master Side:2
Get Data From Master Side:4
Get Data From Master Side:6
Get Data From Master Side:8
......

Do you have any idea on this?

[2548903578]

Hi,

  Yes. I have tried it. I first start the corresponding process of M4 and then load the .ko file, the result is still the same

[igorpadykov]

Hi Shrishail

please try to reproduce issue with Demo Images found on

Embedded Linux for i.MX Applications Processors | NXP 

Best regards
igor
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[s_shrishail]

Hi,

I have used prebuilt images from Nxp and flashed into sd card. But still /dev/ttyRPMSG has not been created

I have followed the following steps on my ubuntu 16.04 machine:

1. Opened 2 terminal one for A7(/dev/ttyUSB0)  and other for M4(/dev/ttyUSB1)

2. Stopped booting in order to enter uboot prompt and followed following steps

  fatload mmc 0:1 0x7F8000 rpmsg_str_echo_bm_example.bin

  dcache flush

  bootaux 0x7F8000

  boot

3. After this in M4 console i am getting following message

RPMSG String Echo Bare Metal Demo...
RPMSG Init as Remote

4. Once booting is done in A7 console. I am able to insert following modules using insmod

imx_rpmsg_tty.ko

imx_rpmsg_tty.ko

But there is no following message on M4 terminal

"Name service handshake is done, M4 has setup a rpmsg channel [1 ---> 1024]"

5. But not able to see /dev/ttyRPMSG entry in /dev folder

6. Without this entry i cant communicate between 2 cortex i can't use the following commans

./unit_tests/mxc_mcc_tty_test.out /dev/ttyRPMSG 115200 R 100 1000 &"

Please help me with the issue.

owing message

[2548903578]

hi, have you solved this problem? I also encountered the same problem as yours, no nodes were created after loading.

[s_shrishail]

No we are debugging on that issue