i.MX ProcessorsのトピックRe: How to start linux after enabeling RPMsg in Devicetree

How to start linux after enabeling RPMsg in Devicetree

erikfriedel — Wed, 30 May 2018 12:21:52 GMT

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 :smileyhappy:

Erik

Re: How to start linux after enabeling RPMsg in Devicetree

dry — Mon, 04 Jun 2018 02:03:19 GMT

If you only have 512MB RAM and you placing rpmsg at the end of it - in the last 1MB somewhere - then your vring placing is way off, as you can see.

Re: How to start linux after enabeling RPMsg in Devicetree

igorpadykov — Mon, 04 Jun 2018 11:22:00 GMT

Hi Erik

please check Warp7 (i.MX7S@512MB LPDDR3) RPMsg patches

Multicore communication on WaRP7 using Remote Processor Messaging bus (RPMsg) - i.MXDev Blog

Best regards
igor
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Re: How to start linux after enabeling RPMsg in Devicetree

BiyongSUN — Fri, 08 Jun 2018 08:06:52 GMT

What's your CMA size?

Re: How to start linux after enabeling RPMsg in Devicetree

BiyongSUN — Fri, 08 Jun 2018 08:08:28 GMT

i.MX Development Miscellanea(i.MX 开发杂记)
https://community.nxp.com/docs/DOC-335198

i.MX6SX_M4_MPU_Settings_For_RPMSG_04132018.pdf

Re: How to start linux after enabeling RPMsg in Devicetree

erikfriedel — Mon, 11 Jun 2018 07:59:58 GMT

Thank you for your answers.

@D. RY where do I have to put my vring then? In the RPMsg patches from igor are the same values I have.

I am now able to boot into Linux thanks to a colleague and when I run "modprobe imx_rpmsg_pingpong", the following message appears:

init pingpong

init pingpong: 0

So it doesn't start to count.

Kmod list shows:

Module Size Used by

imx_rpmsg_pingpong         2038 0
virtio_rpmsg_bus              11468 1 imx_rpmsg_pingpong
virtio                                    7481 1 virtio_rpmsg_bus
virtio_ring                          11266 1 virtio_rpmsg_bus

changes done:

- patches provided by igor

-FreeRTOS set to 9FFF000...

Erik

Re: How to start linux after enabeling RPMsg in Devicetree

dry — Fri, 22 Jun 2018 06:59:59 GMT

Hey Erik

Sorry late replying.

I looked at Biyong 's document he added, and it looked to contain all the details. Have you seen it?

I'm on slightly different SoC and may be BSP not same, I woudn't want to lead you in error.

If both - Linux & FreeRTOS - have now updated address of the vrings, they should find each other.

I'm also not using patches Igor referred to thus wouldn't be able to help straight away.

Re: How to start linux after enabeling RPMsg in Devicetree

erikfriedel — Mon, 25 Jun 2018 06:49:36 GMT

I was able to solve this problem by changing the devicetree a bit and using a clean kernel. After changing the vrings in the kernel and in FreeRTOS it worked.

Thanks for your help.

Re: How to start linux after enabeling RPMsg in Devicetree

nikhil3karale — Mon, 27 Jul 2020 10:48:38 GMT

Hi Erik Friedel,

Could you please tell what changes you did in device tree and in M4 side to run pingpong example. I am also struggling with the same, running pingpong example on custom board with 512 MB RAM .‌