This source code was provided by Sony based on a written source code offer on 5-July-2016.
Covers MediaTek MT53xx/MT58xx-series chips:
MediaTek MT5368 (Cortex-A9 single-core)
MediaTek MT5368_FPGA (ARM11)
MediaTek MT5369 (Cortex-A9 single-core)
MediaTek MT5389 (Arm11)
MediaTek MT5396 (Cortex-A9 dual-core)
MediaTek MT5396_FPGA (ARM11)
MediaTek MT5398 (Cobra Cortex-A9 dual-core)
MediaTek MT5399 (Cobra Cortex-A9 dual-core)
MediaTek MT5861 (Gazelle Cortex-A12 quad-core)
MediaTek MT5880 (Viper Cortex-A9)
MediaTek MT5881 (Arm11)
MediaTek MT5882 (Capri Cortex-A7 quad-core)
MediaTek MT5883 (Lemur Cortex-A7 dual-core)
MediaTek MT5890 (Oryx Cortex-A12 quad-core)
MediaTek MT5891 (Oryx Cortex-A53 quad-core)
Real-world devices known to have these chips: some Sony models
Also see: Rooting MediaTek Based Linux Smart TV / xda-developers
http://forum.xda-developers.com/android/software/rooting-mediatek-based-linux-smart-tv-t3150281
GCC Toolchain for HiSense Smart TVs based on MediaTek MT53xx/MT58xx