OP-TEE was initially developed as
TEE by ST-Ericsson. In 2013, ST-Ericsson achieved compliance with GlobalPlatform’s qualification, proving the APIs were behaving as expected. After the split in 2013 of Ericsson and STMicroelectronics, TEE became owned by STMicroelectronics.
Later in 2013, Linaro formed the Security Working Group (SWG): one of the initial key tasks for the SWG was to work on an open-source TEE project. After talking to various TEE vendors, Linaro began working with the STMicroelectronics TEE project. Before we were able to open-source this code, we needed to replace some proprietary components with open source components. This work took several months with engineers from both STMicroelectronics and Linaro’s SWG making significant contributions. These components included the cryptographic library, secure monitor, build system and others. At the same time, the code base was cleaned up with the application of Coding standards, by running checkpatch, and via other related processes.
On the 12th of June 2014, OP-TEE was born as an open-source project. On that day, the first commit to OP-TEE’s GitHub organisation was pushed. Shortly afterwards, a press release announcing the project was made. During the first year as an open source project, it was owned by STMicroelectronics but jointly maintained by Linaro and STMicroelectronics. In 2015, ownership of the OP-TEE project was transferred from STMicroelectronics to Linaro: since then, Linaro has been the primary owner and maintainer of the project. Maintenance is jointly shared between Linaro, Linaro members and other companies who are using OP-TEE.