Modify, rebuild and reload a firmware

Develop on Arm® Cortex®-M4				What's next
	Install the IDE		Install STM32Cube MP1 package		Modify, rebuild and reload a firmware

1. Overview

This stage will explain you how to modify, rebuild and reload a STM32MP1 Arm® Cortex®-M4 coprocessor firmware.

2. Open SW4STM32 IDE

• Open System Workbench for STM32 IDE

File:SW4STM32 workspace.png

SW4STM32 workspace

3. Disconnect the built in SW4STM32 serial device

• For convenience and as you already have a Linux console connected to the board using minicom, please disconnect the console serial device embedded inside System Workbench for STM32.

File:SW4STM32 workspace serial disconnect 1.png

SW4STM32 disconnect the serial device by clicking this item

File:SW4STM32 workspace serial disconnect 2.png

SW4STM32 disconnect the serial device by clicking this item

4. Import an existing example in SW4STM32 IDE

• Open the import screen File > Import... and select Existing Project into Workspace

File:SW4STM32 import.png

SW4STM32 import screen

• Browse and select OpenAMP_TTY_echo application example
  $HOME/STM32MPU_workspace/STM32MP15-Ecosystem-v1.0.0/Developer-Package/STM32Cube_FW_MP1_V1.0.0/Projects/STM32MP157C-DK2/Applications/OpenAMP/OpenAMP_TTY_echo
• Click finish
• The OpenAMP_TTY_echo project is open and you can browse inside using the left pan

File:SW4STM32 workspace project open.png

SW4STM32 workspace with project open

5. Build the firmware

• Click the build button (the little hammer in the toolbar)

File:SW4STM32 workspace project build.png

SW4STM32 build the project

• If the following screen appear, click OK

File:SW4STM32 workspace project warning.png

SW4STM32 Warning: This board already exists

• Build is finished with no error

File:SW4STM32 workspace project build finished.png

SW4STM32 build finished with no error

6. Upload the firmware

• Upload your firmware example into the board

 cd $HOME/STM32MPU_workspace/STM32MP15-Ecosystem-v1.0.0/Developer-Package/STM32Cube_FW_MP1_V1.0.0/Projects/STM32MP157C-DK2/Applications/OpenAMP/OpenAMP_TTY_echo/SW4STM32/OpenAMP_TTY_echo/
 scp Debug/OpenAMP_TTY_echo.elf root@<board ip address>:/lib/firmware

7. Start the firmware

• Verify that no firmware is currently runnig

 cat /sys/class/remoteproc/remoteproc0/state
offline

If offline is displayed, that means that no firmware is currently running. If running is displayed, a firmware is currently running. You shoul then stop it using the following command

 echo stop > /sys/class/remoteproc/remoteproc0/state

• Set the firmware name to be executed

 echo -n OpenAMP_TTY_echo.elf > /sys/class/remoteproc/remoteproc0/firmware

• Start the firmware

 echo start > /sys/class/remoteproc/remoteproc0/state

• Verify that the firmware is runnig

 cat /sys/class/remoteproc/remoteproc0/state
running

8. Test the firmware

The OpenAMP_TTY_echo firmware do the following:

• CPU2(CM4) initialize OPenAMP MW which initializes/configures IPCC peripheral through HAL and setup openamp-rpmsg framwork infrastructure
• CPU2(CM4) creates 2 rpmsg channels for 2 virtual UART instance UART0 and UART1
• CPU2(CM4) is waiting for messages from CPU1(CA7) on these both channels
• When CPU2(CM4) receives a message on 1 Virtual UART instance/rpmsg channel, it sends the message back to CPU1(CA7) on the same Virtual UART instance

• Initialize the ttyRPMSG0 configuration

 stty -onlcr -echo -F /dev/ttyRPMSG0

• Read constantly the ttyRPMSG0 channels in background

 cat /dev/ttyRPMSG0 &

• Send a message on one ttyRPMSG0 channel and recieve the echo on the same ttyRPMSG0 channel

 echo "Hello Virtual UART0" > /dev/ttyRPMSG0
Hello Virtual UART0

• You can perform the same steps with the ttyRPMSG1 channel

• After playing a while you can stop the firmware

 echo stop > /sys/class/remoteproc/remoteproc0/state

9. Modify the example

The original firmware example receive a message for the host one channel end sent it back to to the host on the same channel.
We propose here to made some modification in the firmware in order to receive a message on one channel and to send the response on the second channel.
Further, we propose to make a led blinking when a message is receive from one channel

10. Rebuild and reload the example

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Inter-Processor Communication Controller

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Universal Asynchronous Receiver/Transmitter