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 | |