• Product Release Status
  • 1.0-Juno
• Linux Kernel BSP
  • The Linux Kernel BSP contains the upstream version 3.15-rc8 of the Linux kernel modified to support the Juno development board.
• Functionality included
  • Linux kernel configures the Juno Compute System and a limited set of peripherals on the Juno development board.
• New features
  • full native resolution on HDMI connectors.
  • USB 1.1 and USB 2.0 devices fully working
  • Initial support for HMP patchset for AArch64. Please note that the patch has not been fine-tuned for Juno yet.
  • Initial support for DVFS
  • Unified defconfig for both standard Linux filesystem and Android
  • Double buffering support when paired with Mali DDK code.
• Limitations
  • No cpuidle support at the moment. Code is present but performance has not been tuned.
• Issues resolved since last release
  • USB keyboard issues fixed
  • Drivers for DVFS and cpufreq
  • SCPI clock framework updated to follow the new MHU driver that uses the mailbox mechanisms
• Test cases and results
  • This release does not contain any test cases or example code other than those already present in the upstream version of the kernel.
• Other information
  • Please refer to the supplied documentation.

This is only a short summary of the steps required in order to build the Linux kernel and the Juno device tree bindings binaries. It assumes that the GNU C cross-compiler used is already set in the $PATH environment variable and that the name prefix for the toolchain executables is 'aarch64-linux-gnu-'. If this is different in your setup, please adjust the command lines accordingly.

• Ensure clean state of the source code deliverable

$ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- mrproper ```

• Initial configuration of the kernel source code

$ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- defconfig ```

• Please note that if you plan to use the kernel with an Android software stack, the provided defconfig enables all the features needed for it.

• Kernel compilation. This step needs to be repeated after changes in the kernel source code.

$ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- -j8 ```

• Device Tree compilation. This step needs to be repeated after changes in the arch/arm64/boot/dts/juno.dts file.

$ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- dtbs ```

• Deployment. The kernel binary will be stored in arch/arm64/boot/Image and the compiled device tree bindings in arch/arm64/boot/dts/juno.dtb. Copy these two files to the SOFTWARE directory on the mounted Juno board storage.

###3. Deploying a root filesystem

• This BSP code has been tested with minimal version of the AArch64 OpenEmbedded filesystem from Linaro.

• Download the filesystem from here: 14.02 minimal release

• Format a partition on the USB mass storage as ext4 filesystem. If another filesystem is preferred then support needs to be enabled in the kernel.

• Mount the USB mass storage on the computer and extract the rootfs as root onto the formatted partition (replace /media/usb_storage with the correct path to the mounted directory)

$ sudo tar zxf linaro-image-minimal-genericarmv8-20140223-649.rootfs.tar.gz -C /media/usb_storage/ ```

• Return to the directory where you have compiled the kernel and install the built modules onto the USB mass storage partition:

$ sudo make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- INSTALL_MOD_PATH=/media/usb_storage modules_install ```

• Unmount the USB mass storage and place it onto the Juno board in one of the USB ports next to the HDMI connectors.

###4. Tools

The Linux kernel BSP depends on the availability of a GNU C cross-compiler that supports ARM's v8 architecture.

###5. Support

Any feedback is to be routed through support@arm.com.