In my project using the TDA4VM chip, I need to use the security function of OP-TEE, and I need to use the HUK (hardware unique key) in OP-TEE as the function of deriving the AES encryption key.
Reference (http://software-dl.ti.com/tisci/esd/latest/6_topic_user_guides/dkek_management.html) I understand that the TDA4VM chip has a DKEK data that can achieve a function similar to HUK. Use the TISCI_MSG_SA2UL_GET_DKEK method to get the DKEK through the tisci interface. But referring to (https://e2e.ti.com/support/processors-group/processors/f/processors-forum/951904/tda4vm-using-derived-kek-on-hs-devices-by-tisci/3526662#3526662) I learned that the TISCI_MSG_SA2UL_GET_DKEK method needs to be called in the secure state, so the data returned by the TISCI_MSG_SA2UL_GET_DKEK method on Linux is wrong. I verified that the TISCI_MSG_SA2UL_GET_DKEK method is available on the MCU. According to my understanding, TEE should also be in a secure state, but the optee-os code does not implement the function of calling tisci.
How to use the tisci interface to get the value of DKEK in the optee-os of TDA4VM?
