iMX8MP RPMSG Device Tree Nodes

[shivani__p]

Hello,

I need to increase the rpmsg shared buffers size as I am facing the below error.

273.067821] imx-rproc imx8mp-cm7: imx_rproc_kick: failed (1, err:-62)
[ 273.128117] imx-rproc imx8mp-cm7: imx_rproc_kick: failed (1, err:-62)
[ 275.224123] imx-rproc imx8mp-cm7: imx_rproc_kick: failed (1, err:-62)
[ 275.283838] imx-rproc imx8mp-cm7: imx_rproc_kick: failed (1, err:-62

-----------------------------------------------------------------------------------------------

rpmsg_multiept virtio0.rpmsg-openamp-demo-channel.-1.1: timeout waiting for a tx buffer.

In device tree rpmsg configuration, I have come across two device nodes for RPMSG. One is "rpmsg" & another is "imx8mp-cm7". These both device nodes are using the different driver. Also, For iMX8MP EVK in "imx8mp-evk-rpmsg.dts" device tree rpmsg device node is being disabled.

So, can please anyone help out what these two device nodes are for? 

Also, what is and why "vdev0vring0", "vdev0vring1", "vdevbuffer" nodes are being added in imx8 platform device tree? How memory is being assigned for these bufferes as in reference manual, it is not given the information regarding the memory for these buffers.

I am attaching the device tree here with.

imx8mp-evk-rpmsg.dts 

Can anyone please help out with the above queries?

Thanks,

Shivani

[BiyongSUN]

check the following document for building up basic concept. 

It is shared memory for communication between A core and M core.

The document is for i.MX6SX, but the knowledge is exactly the same. 

And RPMsg is a common framework of linux. not i.MX.

i.MX Development Miscellanea(i.MX 开发杂记) - NXP Community

08/10/2018:

i.MX6SX M4 MPU Settings For RPMSG update

Update slide CMA Arrangement Consideration

i.MX6SX_M4_MPU_Settings_For_RPMSG_08102018.pdf