Board Support Package (BSP) Development

A BSP is used for compiling a custom image of the operating system. For example, when you need to build a development kit, or when you need to build a new board.

A bootloader is program that starts the device by activating an operating system. It turns on the RAM, voltage controller, and multimedia card (MMC). Most computer architectures including ARM, MIPS, and x86 use U-Boot, an open source primary bootloader.

The mainstream solution is Linux. Usually, SoC manufacturers provide a compatible Linux kernel version or a modified version. Some SoCs are fully supported by the mainline Linux kernel version. There is a possibility to run an alternative OS like WinCE, Windows 10 or any other if it is required.

SoC manufacturers don’t always provide driver source code, and drivers can’t be ported to the mainline kernel version. This is most true for the GPU drivers. So if your platform is fully supported by the mainline kernel, then you can surely use the mainline version of the kernel. If this isn’t the case, then we can prepare a set of patches and include them in your board support package.

To build rootfs we use the following distributions:

• Buildroot
• The Yocto Project
• OpenWrt / LEDE
• The most popular desktop distributions (Debian based, Arch, Gentoo).

A file system isn’t a part of the kernel and is produced separately from kernel development. But some libraries must be compatible with device drivers. For example, the OpenGL library must be compatible with the GPU driver.

To optimize the boot time, we need to work on the following parts of the system: bootloader, kernel, and userspace. To speed up the boot time, we can tweak the system settings, clean up programs that launch at startup, disable unused hardware, upgrade the operating system, and more.

Removing the drivers of unused devices may decrease the boot time. For example, we can disable the network booting mechanism. The kernel can be optimized just like the bootloader – by removing the unused drivers. This will lead to decreasing the size of the bootloader and kernel, and the read time from the SD card or other boot device. To optimize the userspace, we can configure the service run order. For example, network services can be loaded after the main screen has been shown.