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2c162f9b | 1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
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2 | #ifndef _WINDFARM_PID_H |
3 | #define _WINDFARM_PID_H | |
4 | ||
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5 | /* |
6 | * Windfarm PowerMac thermal control. Generic PID helpers | |
7 | * | |
8 | * (c) Copyright 2005 Benjamin Herrenschmidt, IBM Corp. | |
9 | * <benh@kernel.crashing.org> | |
10 | * | |
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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 */ | |
ac171c46 | 77 | s32 last_delta; /* last Tactual - Ttarget */ |
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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); | |
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88 | |
89 | #endif /* _WINDFARM_PID_H */ |