drivers/macintosh/windfarm_pid.h

   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 */