Cross Compiling Hello World (C/C++) for the MitySOM-QC6490¶

An SDK is provided for creating custom applications to run on the MitySOM-QC6490 Devkit. This page will provide steps for compiling and running a C Hello World executable.

Setup the SDK¶

• Download and unzip the latest BSP Release from Repositories_and_Pre-built_Images
• Change into the downloaded directory and run the installer:
  

  ./qcom-wayland-x86_64-qcom-multimedia-image-armv8-2a-qcs6490-mitysom-devkit-toolchain-1.5-ver.1.1.sh
  

• You will be prompted to choose the install location. Choose your desired location or accept the default.
• Once the installation is complete, the toolchain environment setup script will be available for sourcing:
  

  source {YOUR_INSTALL_DIRECTORY}/environment-setup-armv8-2a-qcom-linux
  

  Note: This must be done each time you wish to use the SDK in a new shell session.
• The toolchain is now ready to be used. You can verify the toolchain is setup by ensuring the CC environment variable has been set to the cross compiler:
  

  echo ${CC}
  

  should output

  aarch64-qcom-linux-gcc -march=armv8.2-a+crypto -mbranch-protection=standard -fstack-protector-strong -O2 -D_FORTIFY_SOURCE=2
  -Wformat -Wformat-security -Werror=format-security --sysroot=/usr/local/oecore-x86_64/sysroots/armv8-2a-qcom-linux
  

Create and Compile the Program¶

• Open your favorite text editor and create a file named "hello.c" with the following contents
  

  #include <stdio.h>
  
  int main() {
      printf("Hello, World!\n");
      return 0;
  }
  

• The toolchain can be used directly with Makefile based projects. Lets create a Makefile to compile our hello.c program.
• In the same location as the hello.c file, download this Makefile with the following contents:
  

  all: hello.o
      ${CC} hello.o -o hello
  hello.o: hello.c
      ${CC} -I . -c hello.c
  clean:
      rm -rf *.o
      rm hello
  

  Note: The CC environment variable is the gcc cross compiler targeting the MitySOM-QC6490. For C++ projects, the CXX variable should be substituted in its place to use the g++ cross compiler.
• Source the toolchain setup script if you have not already done so, and run the Makefile:
  

  make all
  

• You should now have an executable named "hello" in the current directory.

Load and Run a Program¶

There are numerous methods for moving files onto the MitySOM-QC6940 Devkit file system. We will use adb for this example.

• See Using Android Debug Bridge (adb) for Remote Access and File Transfers for details on setting up and using adb on the MitySOM-QC6490.
• Move the "hello" executable created in the previous step to the MitySOM-QC6490:
  

  adb push hello /root/hello
  

• In a terminal on the MitySOM-QC6490, run the program:
  

  ./hello
  

  You should see the output Hello, World!

Additional Information¶

The provided SDK is a Yocto Standard SDK, not an Extensible SDK (eSDK).
https://docs.yoctoproject.org/sdk-manual/