Compiling Linux Kernel and Linux Root Filesystem

Overview

You can use Angstrom to generate Linux Kernel, Linux device tree blob and Linux Root Filesystem for the Intel Stratix 10 SoC Development Kit. The steps to do this are documented in the Compiling Linux for Stratix 10. Executing this step also generates the gsrd-console-image-stratix10.tar.xz file (root filesystem as compressed tarball that can be used in step Creating and Updating the SD Card)

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Enabling SGMII and FPGA peripherals

In addition, to enable SGMII you will need to ensure that the Linux device tree is updated with additional EMAC attributes. Also, if you would like to use the FPGA peripherals (FPGA LEDs/Button/DIP SW) connected to the Lightweight H2F bridge you will need to add Altera GPIO driver during Linux kernel compilation. To do this, you can update your source codes with changes mentioned in this page - or compile the Linux kernel and device tree separately as described in section 2, 3 and 4.

Setting up compilation toolchain and environment

Note: this step is required if you intend to compile the Linux kernel separately

1. Launch SoC EDS Command Shell.

2.Download and extract the Linaro toolchain. Then, configure your environment to access the Linaro cross compiler.

$ wget https://releases.linaro.org/components/toolchain/binaries/7.2-2017.11/aarch64-linux-gnu/gcc-linaro-7.2.1-2017.11-x86_64_aarch64-linux-gnu.tar.xz
$ tar xf gcc-linaro-7.2.1-2017.11-x86_64_aarch64-linux-gnu.tar.xz
$ export PATH=$PWD/gcc-linaro-7.2.1-2017.11-x86_64_aarch64-linux-gnu/bin/:$PATH
$ export CROSS_COMPILE=aarch64-linux-gnu- 
$ export ARCH=arm64

Changes in Linux Device Tree to enable SGMII and FPGA Peripherals

The Linux kernel source codes are located at the following git location: https://github.com/altera-opensource/linux-socfpga. You can clone the git by running the following command:

$ cd ~
$ git clone https://github.com/altera-opensource/linux-socfpga
$ cd linux-socfpga
$ git checkout socfpga-4.14.130-ltsi
$ make defconfig

Note: the git branch and tag are continously updated to support the latest LTSI version. If the tag used in this reference design is no longer available, please switch to newer tag or use the latest git branch. Refer to this link for more information regarding the latest kernel branch and tag release.

By default, the Stratix 10 SoC Linux device tree is located at ~/linux-socfpga/arch/arm64/boot/dts/altera/

Replace the content of this folder with the files below:

File name	Description
socfpga_stratix10.dtsi	Updated dtsi file to include EMAC1 and 2 entries to support SGMII
socfpga_stratix10_socdk.dts	Updated dts file to include additional input socfpga_stratix10_ghrd.dtsi
socfpga_stratix10_ghrd.dtsi	Additional dtsi to enable FPGA LED , DIP SW and buttons

Changes in Linux Kernel Compilation to enable FPGA GPIO driver

If you wish to exercse the FPGA peripherals (LED/DIP SW/buttons) connected to the HPS Lightweight bridge, you need to include the Altera GPIO driver during Linux Kernel compilation. Run make menuconfig to bring up the kernel configuration window:

$ make menuconfig

Go to Device Drivers -→ GPIO Support -→ Memory mapped GPIO drivers and ensure that Altera GPIO is selected as shown in the picture below:

Save the changes to .config and exit the kernel configuration window. Run make to start the compilation process.

$ make 

Once compilation is done, the following files are generated:

File name	Description
vmlinux	Linux Kernel ELF file
arch/arm64/boot/Image	Linux Kernel Image
arch/arm64/boot/dts/altera/socfpga_stratix10_socdk.dtb	Device Tree blob for Linux