1============================================= 2Firmware TPM Driver 3============================================= 4 5This document describes the firmware Trusted Platform Module (fTPM) 6device driver. 7 8Introduction 9============ 10 11This driver is a shim for firmware implemented in ARM's TrustZone 12environment. The driver allows programs to interact with the TPM in the same 13way they would interact with a hardware TPM. 14 15Design 16====== 17 18The driver acts as a thin layer that passes commands to and from a TPM 19implemented in firmware. The driver itself doesn't contain much logic and is 20used more like a dumb pipe between firmware and kernel/userspace. 21 22The firmware itself is based on the following paper: 23https://www.microsoft.com/en-us/research/wp-content/uploads/2017/06/ftpm1.pdf 24 25When the driver is loaded it will expose ``/dev/tpmX`` character devices to 26userspace which will enable userspace to communicate with the firmware TPM 27through this device. 28