AM6441: Compiling CMEM for aarch64/arm64

Mark Lombardi

Part Number: AM6441

Hello There,

I was wondering if the CMEM driver module is supported on aarch64/arm64 platforms?

My use case is for setting up DMA transfers from an ARM Cortex M4/M5 Processor to/from ARM Cortex A53 Cores.

I have tried building the cmem module after cloning from git.ti.com, however there are a bunch of undefined errors where it appears some dependencies within the Linux Kernel are only defined for arch/arm and not defined for other platforms including arm64/aarch64.

git clone git://git.ti.com/ipc/ludev.git

cd ludev
export PATH=${HOME}/gcc-arm-8.3-2019.03-x86_64-aarch64-linux-gnu/bin:${PATH}
./configure ARCH=aarch64 CROSS_COMPILE=aarch64-linux-

cmem Configure Log
https://gist.github.com/marklombardi/88551fe0edababd275b6cfa4e619a19c

make -f lu.mak ARCH=aarch64 KERNEL_INSTALL_DIR=/home/user/temp/imx8-linux-dev/KERNEL module

cmem Build Log

https://gist.github.com/marklombardi/adc0c93afc942aa794da4d2027b7db43

over 3 years ago

0 Nick Saulnier over 3 years ago

TI__Guru 72725 points

Hello Mark,

git.ti.com/ipc is the repo for IPC 3.x, which is an older implementation of IPC. We created IPCLLD for use on AM65x, J7, and AM64x.

We are still in the process of writing the AM64x Inter Processor Communication (IPC) documentation, so any feedback is welcome!

Most of our IPC documentation is in the PDK AM64x User's Guide:
https://software-dl.ti.com/processor-sdk-sitara/esd/am64x/latest/exports/docs/rtos/pdk_am64x/docs/userguide/am64x/modules/ipc.html

We also have some information under the Linux SDK documentation:
https://software-dl.ti.com/processor-sdk-sitara/esd/am64x/latest/exports/docs/linux/Foundational_Components_IPCLLD.html

And you can find information about the IPC used in the Benchmark Demo and Servo Drive Demo here:
https://software-dl.ti.com/processor-sdk-sitara/esd/am64x/latest/exports/docs/system/Demo_User_Guides/Benchmark_Demo_User_Guide.html
https://software-dl.ti.com/processor-sdk-sitara/esd/am64x/latest/exports/docs/system/Demo_User_Guides/Servo_Drive_Demo_User_Guide.html

Please let us know if you have any additional questions or feedback.

Regards,

Nick

0 Mark Lombardi over 3 years ago in reply to Nick Saulnier

Prodigy 120 points

Hello Nick,

Thanks for responding.

I had a look though the documentation. I couldn't find any examples that would show how to set-up DMA between the M and A Cores like CMEM supports. Typically a block of shared memory is reserved in the Device Tree that allows the M-4/5 and A53 Cores to share. This memory is mapped into User Space on the ARM side so it is accessible vi Linux Applications.

I am looking to port an Application from the TI AM 5726 that transfers data directly from the M4 Core to DDR RAM via CMEM/DMA.This solution works well.

At this time I am evaluating 64-bit ARM ARMv8 (M4/A53 Quad Core) solutions as well as DMA Libraries to support data transfer without interrupting the main ARM Core until the data has been transferred. CMEM (only appears to support ARMv7/32 Bit). Another possible solution would be to use OpenAMP amongst other contenders.Ideally this AMP library would not be TI specific but work for ARM-64bit AMP processors in general.

At this time I'd just like to know if we need to rule out CMEM as not being supported on 64-bit/ARMv8 platforms or not? So this is not an AM 6441 specific question.

It appears there have been no recent commits to the TI ipc/ludev branch since 2018, if so has CMEM been abandoned? Is there an equivalent to replace it for ARM-64-bit architectures? For example IPCLLD?

https://software-dl.ti.com/processor-sdk-linux/esd/docs/latest/linux/Foundational_Components_CMEM.html

https://git.ti.com/cgit/ipc/ludev/tree/

https://github.com/OpenAMP/open-amp

Thanks,
Mark

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AM6441: Compiling CMEM for aarch64/arm64