1/*
 2 * Windfarm PowerMac thermal control. Generic PID helpers
 3 *
 4 * (c) Copyright 2005 Benjamin Herrenschmidt, IBM Corp.
 5 *                    <benh@kernel.crashing.org>
 6 *
 7 * Released under the term of the GNU GPL v2.
 8 *
 9 * This is a pair of generic PID helpers that can be used by
10 * control loops. One is the basic PID implementation, the
11 * other one is more specifically tailored to the loops used
12 * for CPU control with 2 input sample types (temp and power)
13 */
14
15/*
16 * *** Simple PID ***
17 */
18
19#define WF_PID_MAX_HISTORY	32
20
21/* This parameter array is passed to the PID algorithm. Currently,
22 * we don't support changing parameters on the fly as it's not needed
23 * but could be implemented (with necessary adjustment of the history
24 * buffer
25 */
26struct wf_pid_param {
27	int	interval;	/* Interval between samples in seconds */
28	int	history_len;	/* Size of history buffer */
29	int	additive;	/* 1: target relative to previous value */
30	s32	gd, gp, gr;	/* PID gains */
31	s32	itarget;	/* PID input target */
32	s32	min,max;	/* min and max target values */
33};
34
35struct wf_pid_state {
36	int	first;				/* first run of the loop */
37	int	index; 				/* index of current sample */
38	s32	target;				/* current target value */
39	s32	samples[WF_PID_MAX_HISTORY];	/* samples history buffer */
40	s32	errors[WF_PID_MAX_HISTORY];	/* error history buffer */
41
42	struct wf_pid_param param;
43};
44
45extern void wf_pid_init(struct wf_pid_state *st, struct wf_pid_param *param);
46extern s32 wf_pid_run(struct wf_pid_state *st, s32 sample);
47
48
49/*
50 * *** CPU PID ***
51 */
52
53#define WF_CPU_PID_MAX_HISTORY	32
54
55/* This parameter array is passed to the CPU PID algorithm. Currently,
56 * we don't support changing parameters on the fly as it's not needed
57 * but could be implemented (with necessary adjustment of the history
58 * buffer
59 */
60struct wf_cpu_pid_param {
61	int	interval;	/* Interval between samples in seconds */
62	int	history_len;	/* Size of history buffer */
63	s32	gd, gp, gr;	/* PID gains */
64	s32	pmaxadj;	/* PID max power adjust */
65	s32	ttarget;	/* PID input target */
66	s32	tmax;		/* PID input max */
67	s32	min,max;	/* min and max target values */
68};
69
70struct wf_cpu_pid_state {
71	int	first;				/* first run of the loop */
72	int	index; 				/* index of current power */
73	int	tindex; 			/* index of current temp */
74	s32	target;				/* current target value */
75	s32	last_delta;			/* last Tactual - Ttarget */
76	s32	powers[WF_PID_MAX_HISTORY];	/* power history buffer */
77	s32	errors[WF_PID_MAX_HISTORY];	/* error history buffer */
78	s32	temps[2];			/* temp. history buffer */
79
80	struct wf_cpu_pid_param param;
81};
82
83extern void wf_cpu_pid_init(struct wf_cpu_pid_state *st,
84			    struct wf_cpu_pid_param *param);
85extern s32 wf_cpu_pid_run(struct wf_cpu_pid_state *st, s32 power, s32 temp);

 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 */
28struct 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
37struct 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
47extern void wf_pid_init(struct wf_pid_state *st, struct wf_pid_param *param);
48extern 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 */
62struct 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
72struct 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
85extern void wf_cpu_pid_init(struct wf_cpu_pid_state *st,
86			    struct wf_cpu_pid_param *param);
87extern s32 wf_cpu_pid_run(struct wf_cpu_pid_state *st, s32 power, s32 temp);
88
89#endif /* _WINDFARM_PID_H */