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- .. SPDX-License-Identifier: GPL-2.0-only
- ========
- Overview
- ========
- The Platform Environment Control Interface (PECI) is a communication
- interface between Intel processor and management controllers
- (e.g. Baseboard Management Controller, BMC).
- PECI provides services that allow the management controller to
- configure, monitor and debug platform by accessing various registers.
- It defines a dedicated command protocol, where the management
- controller is acting as a PECI originator and the processor - as
- a PECI responder.
- PECI can be used in both single processor and multiple-processor based
- systems.
- NOTE:
- Intel PECI specification is not released as a dedicated document,
- instead it is a part of External Design Specification (EDS) for given
- Intel CPU. External Design Specifications are usually not publicly
- available.
- PECI Wire
- ---------
- PECI Wire interface uses a single wire for self-clocking and data
- transfer. It does not require any additional control lines - the
- physical layer is a self-clocked one-wire bus signal that begins each
- bit with a driven, rising edge from an idle near zero volts. The
- duration of the signal driven high allows to determine whether the bit
- value is logic '0' or logic '1'. PECI Wire also includes variable data
- rate established with every message.
- For PECI Wire, each processor package will utilize unique, fixed
- addresses within a defined range and that address should
- have a fixed relationship with the processor socket ID - if one of the
- processors is removed, it does not affect addresses of remaining
- processors.
- PECI subsystem internals
- ------------------------
- .. kernel-doc:: include/linux/peci.h
- .. kernel-doc:: drivers/peci/internal.h
- .. kernel-doc:: drivers/peci/core.c
- .. kernel-doc:: drivers/peci/request.c
- PECI CPU Driver API
- -------------------
- .. kernel-doc:: drivers/peci/cpu.c
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