1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 #ifndef _WINDFARM_PID_H 3 #define _WINDFARM_PID_H 4 5 /* 6 * Windfarm PowerMac thermal control. Generic PID helpers 7 * 8 * (c) Copyright 2005 Benjamin Herrenschmidt, IBM Corp. 9 * <benh@kernel.crashing.org> 10 * 11 * This is a pair of generic PID helpers that can be used by 12 * control loops. One is the basic PID implementation, the 13 * other one is more specifically tailored to the loops used 14 * for CPU control with 2 input sample types (temp and power) 15 */ 16 17 /* 18 * *** Simple PID *** 19 */ 20 21 #define WF_PID_MAX_HISTORY 32 22 23 /* This parameter array is passed to the PID algorithm. Currently, 24 * we don't support changing parameters on the fly as it's not needed 25 * but could be implemented (with necessary adjustment of the history 26 * buffer 27 */ 28 struct wf_pid_param { 29 int interval; /* Interval between samples in seconds */ 30 int history_len; /* Size of history buffer */ 31 int additive; /* 1: target relative to previous value */ 32 s32 gd, gp, gr; /* PID gains */ 33 s32 itarget; /* PID input target */ 34 s32 min,max; /* min and max target values */ 35 }; 36 37 struct wf_pid_state { 38 int first; /* first run of the loop */ 39 int index; /* index of current sample */ 40 s32 target; /* current target value */ 41 s32 samples[WF_PID_MAX_HISTORY]; /* samples history buffer */ 42 s32 errors[WF_PID_MAX_HISTORY]; /* error history buffer */ 43 44 struct wf_pid_param param; 45 }; 46 47 extern void wf_pid_init(struct wf_pid_state *st, struct wf_pid_param *param); 48 extern s32 wf_pid_run(struct wf_pid_state *st, s32 sample); 49 50 51 /* 52 * *** CPU PID *** 53 */ 54 55 #define WF_CPU_PID_MAX_HISTORY 32 56 57 /* This parameter array is passed to the CPU PID algorithm. Currently, 58 * we don't support changing parameters on the fly as it's not needed 59 * but could be implemented (with necessary adjustment of the history 60 * buffer 61 */ 62 struct wf_cpu_pid_param { 63 int interval; /* Interval between samples in seconds */ 64 int history_len; /* Size of history buffer */ 65 s32 gd, gp, gr; /* PID gains */ 66 s32 pmaxadj; /* PID max power adjust */ 67 s32 ttarget; /* PID input target */ 68 s32 tmax; /* PID input max */ 69 s32 min,max; /* min and max target values */ 70 }; 71 72 struct wf_cpu_pid_state { 73 int first; /* first run of the loop */ 74 int index; /* index of current power */ 75 int tindex; /* index of current temp */ 76 s32 target; /* current target value */ 77 s32 last_delta; /* last Tactual - Ttarget */ 78 s32 powers[WF_PID_MAX_HISTORY]; /* power history buffer */ 79 s32 errors[WF_PID_MAX_HISTORY]; /* error history buffer */ 80 s32 temps[2]; /* temp. history buffer */ 81 82 struct wf_cpu_pid_param param; 83 }; 84 85 extern void wf_cpu_pid_init(struct wf_cpu_pid_state *st, 86 struct wf_cpu_pid_param *param); 87 extern s32 wf_cpu_pid_run(struct wf_cpu_pid_state *st, s32 power, s32 temp); 88 89 #endif /* _WINDFARM_PID_H */ 90