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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 | // SPDX-License-Identifier: GPL-2.0-only /* * Windfarm PowerMac thermal control. Generic PID helpers * * (c) Copyright 2005 Benjamin Herrenschmidt, IBM Corp. * <benh@kernel.crashing.org> */ #include <linux/types.h> #include <linux/errno.h> #include <linux/kernel.h> #include <linux/string.h> #include <linux/module.h> #include "windfarm_pid.h" #undef DEBUG #ifdef DEBUG #define DBG(args...) printk(args) #else #define DBG(args...) do { } while(0) #endif void wf_pid_init(struct wf_pid_state *st, struct wf_pid_param *param) { memset(st, 0, sizeof(struct wf_pid_state)); st->param = *param; st->first = 1; } EXPORT_SYMBOL_GPL(wf_pid_init); s32 wf_pid_run(struct wf_pid_state *st, s32 new_sample) { s64 error, integ, deriv; s32 target; int i, hlen = st->param.history_len; /* Calculate error term */ error = new_sample - st->param.itarget; /* Get samples into our history buffer */ if (st->first) { for (i = 0; i < hlen; i++) { st->samples[i] = new_sample; st->errors[i] = error; } st->first = 0; st->index = 0; } else { st->index = (st->index + 1) % hlen; st->samples[st->index] = new_sample; st->errors[st->index] = error; } /* Calculate integral term */ for (i = 0, integ = 0; i < hlen; i++) integ += st->errors[(st->index + hlen - i) % hlen]; integ *= st->param.interval; /* Calculate derivative term */ deriv = st->errors[st->index] - st->errors[(st->index + hlen - 1) % hlen]; deriv /= st->param.interval; /* Calculate target */ target = (s32)((integ * (s64)st->param.gr + deriv * (s64)st->param.gd + error * (s64)st->param.gp) >> 36); if (st->param.additive) target += st->target; target = max(target, st->param.min); target = min(target, st->param.max); st->target = target; return st->target; } EXPORT_SYMBOL_GPL(wf_pid_run); void wf_cpu_pid_init(struct wf_cpu_pid_state *st, struct wf_cpu_pid_param *param) { memset(st, 0, sizeof(struct wf_cpu_pid_state)); st->param = *param; st->first = 1; } EXPORT_SYMBOL_GPL(wf_cpu_pid_init); s32 wf_cpu_pid_run(struct wf_cpu_pid_state *st, s32 new_power, s32 new_temp) { s64 integ, deriv, prop; s32 error, target, sval, adj; int i, hlen = st->param.history_len; /* Calculate error term */ error = st->param.pmaxadj - new_power; /* Get samples into our history buffer */ if (st->first) { for (i = 0; i < hlen; i++) { st->powers[i] = new_power; st->errors[i] = error; } st->temps[0] = st->temps[1] = new_temp; st->first = 0; st->index = st->tindex = 0; } else { st->index = (st->index + 1) % hlen; st->powers[st->index] = new_power; st->errors[st->index] = error; st->tindex = (st->tindex + 1) % 2; st->temps[st->tindex] = new_temp; } /* Calculate integral term */ for (i = 0, integ = 0; i < hlen; i++) integ += st->errors[(st->index + hlen - i) % hlen]; integ *= st->param.interval; integ *= st->param.gr; sval = st->param.tmax - (s32)(integ >> 20); adj = min(st->param.ttarget, sval); DBG("integ: %lx, sval: %lx, adj: %lx\n", integ, sval, adj); /* Calculate derivative term */ deriv = st->temps[st->tindex] - st->temps[(st->tindex + 2 - 1) % 2]; deriv /= st->param.interval; deriv *= st->param.gd; /* Calculate proportional term */ prop = st->last_delta = (new_temp - adj); prop *= st->param.gp; DBG("deriv: %lx, prop: %lx\n", deriv, prop); /* Calculate target */ target = st->target + (s32)((deriv + prop) >> 36); target = max(target, st->param.min); target = min(target, st->param.max); st->target = target; return st->target; } EXPORT_SYMBOL_GPL(wf_cpu_pid_run); MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>"); MODULE_DESCRIPTION("PID algorithm for PowerMacs thermal control"); MODULE_LICENSE("GPL"); |