OpenAMP DSP AMP Sample

Browse source code on GitHub

Overview

This application demonstrates how to use OpenAMP for multi-core communication on NXP RT700 series processors. It showcases concurrent OpenAMP communication from a primary core (CM33_0) to multiple remote cores:

  • CM33_0 ↔ CM33_1: Inter-processor communication between Cortex-M33 cores

  • CM33_0 ↔ HiFi4 DSP: Communication between ARM Cortex-M33 and Cadence HiFi4 DSP

The application demonstrates:

  • Multiple concurrent OpenAMP/RPMSG instances

  • Separate shared memory regions for each communication channel

  • Independent message passing with different remote cores

  • Proper resource isolation and synchronization

Architecture

The sample consists of three separate applications:

  1. Primary Core (CM33_0):

    • Runs two concurrent threads

    • Manages communication with both CM33_1 and HiFi4 DSP

    • Acts as RPMSG host for both channels

  2. Remote CM33 Core (CM33_1):

    • Runs as RPMSG remote

    • Communicates with CM33_0 via dedicated shared memory

  3. Remote DSP Core (HiFi4):

    • Runs as RPMSG remote

    • Communicates with CM33_0 via separate shared memory region

Building the application for mimxrt700_evk

# From the root of the zephyr repository
west build -b mimxrt700_evk/mimxrt798s/cm33_cpu0 --sysbuild samples/boards/nxp/adsp/rtxxx/amp_talk/
west debug

Open a serial terminal (minicom, putty, etc.) and connect the board with the following settings:

  • Speed: 115200

  • Data: 8 bits

  • Parity: None

  • Stop bits: 1

Reset the board and the following message will appear on the corresponding serial port, one is main another is remote:

*** Booting Zephyr OS build v4.2.0-4126-g68238d6377d2 ***
 [ARM] Starting DSP...
 *** Booting Zephyr OS build v4.2.0-4126-g68238d6377d2 ***
 [DSP] Starting application thread!
 OpenAMP[DSP] demo started
 Starting application threads!

 OpenAMP[main->CM33] demo started
 Main core received a message: 1
 Main core received a message: 3
 Main core received a message: 5
 Main core received a message: 7
 Main core received a message: 9
 Main core received a message: 11
 ...
 Main core received a message: 97
 Main core received a message: 99
 OpenAMP demo ended.

 OpenAMP[main->DSP] demo started
 [DSP] Remote core received a message: 0
 Main core received a message: 1
 [DSP] Remote core received a message: 2
 Main core received a message: 3
 [DSP] Remote core received a message: 4
 Main core received a message: 5
 [DSP] Remote core received a message: 6
 Main core received a message: 7
 [DSP] Remote core received a message: 8
 Main core received a message: 9
 [DSP] Remote core received a message: 10
 Main core received a message: 11
 ...
 [DSP] Remote core received a message: 98
 Main core received a message: 99
 OpenAMP demo ended.
 [DSP] OpenAMP demo ended.

*** Booting Zephyr OS build v4.2.0-4126-g68238d6377d2 ***
Starting application thread!

OpenAMP[remote] demo started
Remote core received a message: 0
Remote core received a message: 2
Remote core received a message: 4
Remote core received a message: 6
Remote core received a message: 8
Remote core received a message: 10
Remote core received a message: 12
...
Remote core received a message: 96
Remote core received a message: 98
OpenAMP demo ended.

Key Features

  • Concurrent Communication: Primary core manages two independent OpenAMP channels simultaneously

  • Resource Isolation: Each communication channel uses separate shared memory regions and IPM instances

  • Multi-Architecture Support: Demonstrates ARM Cortex-M33 to Cortex-M33 and ARM to DSP communication

  • Scalable Design: Architecture can be extended to support additional remote cores

Technical Details

The implementation uses:

  • Separate RPMSG virtio devices for each communication channel

  • Independent shared memory pools and regions

  • Dedicated IPM (Inter-Processor Messaging) instances

  • Proper OpenAMP resource management and cleanup

This sample serves as a reference for implementing complex multi-core communication scenarios in embedded systems using the OpenAMP framework.

See also

IPM