Raspberry Pi primed for new OS after drivers are fully open sourced

Raspberry Pi primed for new OS after drivers are fully open sourced

Summary: Efforts to bring new operating systems like Risc OS and FreeBSD to the cheap Linux board have been given a boost by a decision to fully open-source drivers for its ARM-based SoC.

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The £25 Raspberry Pi now has fully open-source drivers for its ARM System on a Chip (SoC) — paving the way for new operating systems like the Risc OS and Bell Labs Plan 9 to be brought to the board.

The Raspberry Pi Foundation on Wednesday released previously closed-source graphics libraries under the open-source BSD 3-Clause licence. These graphics libraries allow the board's ARM11 CPU to interact with its VideoCore IV GPU to manipulate 2D and 3D graphics.

Raspberry Pi
The Model B Raspberry Pi, which now ships with 512MB of RAM. Image: Charles McLellan

The libraries, which include implementations of the OpenGL/ES and OpenVG APIs, are available from the foundation's userland repository on GitHub.

The move means every driver that interacts with the board's ARM CPU is now open source. This will make it easier to port new operating systems to the device — which already runs a range of Linux distributions, including Debian and Arch Linux. It has been welcomed by groups working to port the Risc OS, FreeBSD and Plan9 — the Bell Labs OS named after the movie Plan 9 from Outer Space — to the device.

"It means developers can port those libraries to alternative operating systems," said Alex Bradbury, lead Linux developer for the Raspberry Pi.

"The Raspberry Pi is a really good piece of hardware for demonstrating niche or specialised OS. This will mean they can more easily take advantage of all the capabilities the device has."

The code inside these graphics libraries was previously locked away inside binaries compiled for Linux. This inaccessibility meant the only way for developers to allow an OS other than Linux to manipulate the Pi's graphics using its GPU was to reverse-engineer those libraries and write them from scratch. Now the code is freely available online, it can be modified by developers to allow alternative OSes to utilise the Pi's GPU.

The open-source libraries will also make it easier for the Pi to support alternative windowing systems, such as Wayland. This will allow GPU-accelerated GUI features — for example, compositing of windows.

Broadcom on side

The move to open-source the libraries was only made possible by getting agreement from chip vendor Broadcom, which makes the BCM2835 SoC the Pi is based on.

Broadcom is the first vendor to entirely open-source drivers for an ARM-based multimedia SoC. Bradbury said the Foundation had persuaded Broadcom to open up its drivers by pointing out the benefits of such a move.

"We successfully convinced them that the risk of losing some important IP in this case is very low, and it would make a large number of developers very happy," he said.

The risk of the move revealing proprietary elements of the chip design is low in Broadcom's case, he said, because of the way the hardware and software stack has been designed.

"It's easier for Broadcom to open-source this code due to the architecture of their GPU as the interface between the GPU and CPU is relatively high level, so there's limited secret sauce in the ARM-side stuff that's been opened up," Bradbury said.

He hopes that other vendors selling ARM-based systems will follow in Broadcom's footsteps and open-source their drivers.

"The fact that everything that runs on ARM is now fully open has very good practical benefits, and I hope that other vendors will try and provide those benefits to the community," he said.

Bradbury described the BSD 3-Clause licence as "incredibly permissive". It allows users to modify or distribute the code in any manner they wish, providing they credit the owner.

Topics: Open Source, Hardware, Linux, Operating Systems, Software Development

About

Nick Heath is chief reporter for TechRepublic UK. He writes about the technology that IT-decision makers need to know about, and the latest happenings in the European tech scene.

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7 comments
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  • Nice to see FreeBSD make the front page at ZDNet

    ZDNet's open-source bloggers rarely mention FreeBSD (or any other BSD).

    Thanks, Nick.
    Rabid Howler Monkey
  • Raspberry Pi primed for new OS after drivers are fully open sourced

    FreeBSD on this device -- now you have my attention Raspberry Pi.
    Loverock Davidson-
    • Mr. Davidson

      Since you are a connoisseur of BSD, you should peruse the Debian GNU/kFreeBSD port where the FreeBSD kernel has replaced the Linux kernel. Debian's package management (via apt) is much more friendly than FreeBSD ports.
      Rabid Howler Monkey
  • FreeBSD for Raspberry Pi... Nice!

    Now can we have m0n0wall on Raspberry Pi?
    Samic
  • the pi

    just keeps getting better
    Scarface Claw
  • Open Sauce

    Well this is the first and last time I post anything on Znet.
    Philb3
  • Not Really That Big A Step Forward

    Turns out these "drivers" are nothing more than glue wrappers for passing calls into the GPU firmware, which is where all the real action takes place. So open-sourcing them doesn't allow for important capabilities like adding new OpenGL features--you're still stuck with just the functionality the firmware allows, and new functionality can only come with new firmware from Broadcom.
    ldo17