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- /* 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 */
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