// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2009-2010 Intel Corporation
*
* Authors:
* Jesse Barnes <jbarnes@virtuousgeek.org>
*/
/*
* Some Intel Ibex Peak based platforms support so-called "intelligent
* power sharing", which allows the CPU and GPU to cooperate to maximize
* performance within a given TDP (thermal design point). This driver
* performs the coordination between the CPU and GPU, monitors thermal and
* power statistics in the platform, and initializes power monitoring
* hardware. It also provides a few tunables to control behavior. Its
* primary purpose is to safely allow CPU and GPU turbo modes to be enabled
* by tracking power and thermal budget; secondarily it can boost turbo
* performance by allocating more power or thermal budget to the CPU or GPU
* based on available headroom and activity.
*
* The basic algorithm is driven by a 5s moving average of temperature. If
* thermal headroom is available, the CPU and/or GPU power clamps may be
* adjusted upwards. If we hit the thermal ceiling or a thermal trigger,
* we scale back the clamp. Aside from trigger events (when we're critically
* close or over our TDP) we don't adjust the clamps more than once every
* five seconds.
*
* The thermal device (device 31, function 6) has a set of registers that
* are updated by the ME firmware. The ME should also take the clamp values
* written to those registers and write them to the CPU, but we
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