At an event this weekend (YouTube stream), Samsung said they will open-source the kernel and platform components of their Exynos SoC. This new code is said to be dual-licensed under the GPLv2 and Apache 2.0 licenses.
Samsung also says it will support ARM Mali GPU driver development, which it uses with its Exynos SoC. It's not known at the moment whether this means supporting the community Lima driver project or something else.
As part of this new open-source initiative, Samsung looks like it will be upping its Linux support for the Origenboard, its primary Exynos development board.
Up to this point for Exynos there's been bits of open-source drivers, like their Exynos DRM driver that is in the mainline Linux kernel but the 3D bits are not covered and they have no open-source user-space for 3D / OpenGL ES coverage.
It will be interesting to see what Samsung ultimately does with their Exynos open-source play since most ARM SoC vendors aren't too open-source friendly up to this point. It was just days ago though that word on the new Google Chromebook emerged, which boasts a Samsung Exynos 5250 SoC with Cortex-A15 cores.
Google certainly does like open-source for their ChromeOS work such as their work on Coreboot support for new hardware and Google's work on open-source graphics drivers for use by their earlier Intel-based Chromebooks.