When it comes to operating systems, Linux® is perhaps the world’s most popular open source OS. Linux has been running on thousands of MIPS devices that have shipped in very large volume (north of several billions of units).

The MIPS ISA (MIPS32, MIPS64 and microMIPS) is fully supported in Linux, with Imagination and our licensees providing frequent patches for new architecture implementations and features. A stable branch from Imagination can be found at www.linux-mips.org.

linux_mipx_tuxMIPS Linux is a port of the Linux operating system to the MIPS CPU architecture

What’s new in Linux 3.16

The recently announced Linux 3.16 kernel introduces support for the MIPS64-based Cavium Octeon III comms processors, one of the most advanced 64-bit processor families available on the market today. OCTEON III provides among the highest compute power density of any standards-based communications processors, scaling up to 48 cnMIPS cores per chip.

Additionally, the Linux 3.16 kernel for MIPS adds para-virtualization support and brings several performance improvements for MIPS64-based Broadcom XLP SoCs and Malta evaluation boards. Linux SMP can now handle clusters of up to 256 MIPS CPUs.

Linux for MIPS - Up-stream Linux kernel patches

An overview of the number of patches up-streamed to the Linux kernel since Imagination acquired MIPS

A lot of the work we’ve done recently has been focused on optimizing the latest Linux kernel for the latest features of the MIPS Warrior family. This includes adding new instructions and providing fixes and updates to support architectural specifications such as EVA (Enhanced Virtual Addressing), CPS (Coherent Processing System), GIC (Global Interrupt Controller), VZ (Virtualization) and others.

A major step forward for the proliferation of Linux for MIPS was the announcement of the prpl foundation. prpl is an open source, community-driven, collaborative, non-profit foundation supporting the MIPS architecture – and open to others – with a focus on enabling next-generation datacenter-to-device portable software and virtualized architectures.

prplThe founding members of the prpl foundation

There are multiple Linux distributions available for MIPS

Imagination has been actively supporting the development of Linux kernel and distributions by engaging with different developers, sponsoring Linux summits, enabling hardware access and maintaining a close link with universities and organizations developing Linux for MIPS.

Distributions that run on MIPS CPUs range from Buildroot and OpenWrt for routers and other networking devices to Debian for desktop and servers.

Debian is an all-volunteer organization dedicated to developing free software and promoting the ideals of the open source community. Debian distributions support both 32- and 64-bit MIPS-based processors.

loongson-3a-0Several Yeeloong notebooks from Lemote use MIPS-based Longsoon processors and run GNU/Linux

OpenWrt is an embedded operating system based on the Linux kernel, and primarily used on MIPS-based embedded devices from Qualcomm Atheros, MediaTek and others to route network traffic. One of the first areas of focus for prpl is to enhance and complement OpenWrt and to drive its carrier grade features to the next level.

Buildroot is useful mainly for developers working with small or embedded systems, using CPU architectures like MIPS; it automates the building process of your embedded system and eases the cross-compilation process. Buildroot contains a set of makefiles and patches which can be used to easily generate a complete embedded Linux system. Buildroot can generate any or all of the elements required to run Linux on MIPS: a cross-compilation toolchain, a root filesystem, a kernel image and a bootloader image.

Another popular distribution for MIPS is Gentoo. Gentoo/MIPS is a port of the Gentoo GNU/Linux and the Gentoo Portage package management system to MIPS-based platforms. To strengthen our collaboration with Gentoo, Imagination has donated MIPS64-based platforms and offered software support for up-to-date root file system builds for MIPS. For those interested in running Gentoo/MIPS, you can get started by reading their handbook and the FAQ page; more help can be obtained by subscribing to the gentoo-mips mailing list.

If you want to find out more about Linux for MIPS, check out our MIPS Insider community portal and developer forums. For the latest news and announcements on MIPS, follow us on Twitter (@ImaginationPR, @MIPSGuru) and keep coming back to our blog.