/* SPDX-License-Identifier: GPL-2.0-only */ #ifndef _WINDFARM_PID_H #define _WINDFARM_PID_H /* * Windfarm PowerMac thermal control. Generic PID helpers * * (c) Copyright 2005 Benjamin Herrenschmidt, IBM Corp. * <benh@kernel.crashing.org> * * This is a pair of generic PID helpers that can be used by * control loops. One is the basic PID implementation, the * other one is more specifically tailored to the loops used * for CPU control with 2 input sample types (temp and power) */ /* * *** Simple PID *** */ #define WF_PID_MAX_HISTORY 32 /* This parameter array is passed to the PID algorithm. Currently, * we don't support changing parameters on the fly as it's not needed * but could be implemented (with necessary adjustment of the history * buffer */ struct wf_pid_param { int interval; /* Interval between samples in seconds */ int history_len; /* Size of history buffer */ int additive; /* 1: target relative to previous value */ s32 gd, gp, gr; /* PID gains */ s32 itarget; /* PID input target */ s32 min,max; /* min and max target values */ }; struct wf_pid_state { int first; /* first run of the loop */ int index; /* index of current sample */ s32 target; /* current target value */ s32 samples[WF_PID_MAX_HISTORY]; /* samples history buffer */ s32 errors[WF_PID_MAX_HISTORY]; /* error history buffer */ struct wf_pid_param param; }; extern void wf_pid_init(struct wf_pid_state *st, struct wf_pid_param *param); extern s32 wf_pid_run(struct wf_pid_state *st, s32 sample); /* * *** CPU PID *** */ #define WF_CPU_PID_MAX_HISTORY 32 /* This parameter array is passed to the CPU PID algorithm. Currently, * we don't support changing parameters on the fly as it's not needed * but could be implemented (with necessary adjustment of the history * buffer */ struct wf_cpu_pid_param { int interval; /* Interval between samples in seconds */ int history_len; /* Size of history buffer */ s32 gd, gp, gr; /* PID gains */ s32 pmaxadj; /* PID max power adjust */ s32 ttarget; /* PID input target */ s32 tmax; /* PID input max */ s32 min,max; /* min and max target values */ }; struct wf_cpu_pid_state { int first; /* first run of the loop */ int index; /* index of current power */ int tindex; /* index of current temp */ s32 target; /* current target value */ s32 last_delta; /* last Tactual - Ttarget */ s32 powers[WF_PID_MAX_HISTORY]; /* power history buffer */ s32 errors[WF_PID_MAX_HISTORY]; /* error history buffer */ s32 temps[2]; /* temp. history buffer */ struct wf_cpu_pid_param param; }; extern void wf_cpu_pid_init(struct wf_cpu_pid_state *st, struct wf_cpu_pid_param *param); extern s32 wf_cpu_pid_run(struct wf_cpu_pid_state *st, s32 power, s32 temp); #endif /* _WINDFARM_PID_H */