IPM with ARM MHU

Overview

An MHU (Message Handling Unit) enables software to raise interrupts to the processor cores. This sample is a simple dual-core example for a Musca A1 board that has two MHU units. This sample only test MHU0, the steps are:

CPU 0 will wake up CPU 1 after initialization
CPU 1 will send to CPU 0 an interrupt over MHU0
CPU 0 return the same to CPU 1 when received MHU0 interrupt
Test done when CPU 1 received MHU0 interrupt

Building and Running

On Musca B1

This project outputs ‘IPM MHU sample on musca_b1’ to the console. It can be built and executed on Musca B1 CPU 0 as follows:

west build -b v2m_musca_b1/musca_b1 samples/drivers/ipm/ipm_mhu_dual_core
west build -t run

This project outputs ‘IPM MHU sample on v2m_musca_b1_ns’ to the console. It can be built and executed on Musca B1 CPU 1 as follows:

west build -b v2m_musca_b1/musca_b1/ns samples/drivers/ipm/ipm_mhu_dual_core
west build -t run

Combine images for Musca

A third-party tool (srecord) is used to generate the Intel formatted hex image. For more information refer to the Srecord Manual.

srec_cat zephyr.bin -Binary -offset $IMAGE_OFFSET zephyr_nonsecure.bin -Binary -offset $IMAGE_NS_OFFSET -o dual_core_zephyr.hex -Intel

# This command is an example for Musca B1
srec_cat zephyr.bin -Binary -offset 0xA000000 zephyr_nonsecure.bin -Binary -offset 0xA060400 -o dual_core_zephyr.hex -Intel

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.

Sample Output

***** Booting Zephyr OS zephyr-v1.13.0-3378-g3625524 *****
IPM MHU sample on musca_a
CPU 0, get MHU0 success!
***** Booting Zephyr OS zephyr-v1.13.0-3378-g3625524 *****
IPM MHU sample on musca_a_nonsecure
CPU 1, get MHU0 success!
MHU ISR on CPU 0
MHU ISR on CPU 1
MHU Test Done.