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e151a202 D |
1 | /* |
2 | * step_wise.c - A step-by-step Thermal throttling governor | |
3 | * | |
4 | * Copyright (C) 2012 Intel Corp | |
5 | * Copyright (C) 2012 Durgadoss R <durgadoss.r@intel.com> | |
6 | * | |
7 | * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or modify | |
10 | * it under the terms of the GNU General Public License as published by | |
11 | * the Free Software Foundation; version 2 of the License. | |
12 | * | |
13 | * This program is distributed in the hope that it will be useful, but | |
14 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | * General Public License for more details. | |
17 | * | |
18 | * You should have received a copy of the GNU General Public License along | |
19 | * with this program; if not, write to the Free Software Foundation, Inc., | |
20 | * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. | |
21 | * | |
22 | * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | |
23 | */ | |
24 | ||
e151a202 D |
25 | #include <linux/thermal.h> |
26 | ||
27 | #include "thermal_core.h" | |
28 | ||
29 | /* | |
30 | * If the temperature is higher than a trip point, | |
31 | * a. if the trend is THERMAL_TREND_RAISING, use higher cooling | |
32 | * state for this trip point | |
33 | * b. if the trend is THERMAL_TREND_DROPPING, use lower cooling | |
34 | * state for this trip point | |
3dbfff3d ZR |
35 | * c. if the trend is THERMAL_TREND_RAISE_FULL, use upper limit |
36 | * for this trip point | |
37 | * d. if the trend is THERMAL_TREND_DROP_FULL, use lower limit | |
38 | * for this trip point | |
39 | * If the temperature is lower than a trip point, | |
40 | * a. if the trend is THERMAL_TREND_RAISING, do nothing | |
41 | * b. if the trend is THERMAL_TREND_DROPPING, use lower cooling | |
42 | * state for this trip point, if the cooling state already | |
43 | * equals lower limit, deactivate the thermal instance | |
44 | * c. if the trend is THERMAL_TREND_RAISE_FULL, do nothing | |
45 | * d. if the trend is THERMAL_TREND_DROP_FULL, use lower limit, | |
46 | * if the cooling state already equals lower limit, | |
47 | * deactive the thermal instance | |
e151a202 D |
48 | */ |
49 | static unsigned long get_target_state(struct thermal_instance *instance, | |
3dbfff3d | 50 | enum thermal_trend trend, bool throttle) |
e151a202 D |
51 | { |
52 | struct thermal_cooling_device *cdev = instance->cdev; | |
53 | unsigned long cur_state; | |
ca56caa0 | 54 | unsigned long next_target; |
e151a202 | 55 | |
ca56caa0 EV |
56 | /* |
57 | * We keep this instance the way it is by default. | |
58 | * Otherwise, we use the current state of the | |
59 | * cdev in use to determine the next_target. | |
60 | */ | |
e151a202 | 61 | cdev->ops->get_cur_state(cdev, &cur_state); |
ca56caa0 | 62 | next_target = instance->target; |
06475b55 | 63 | dev_dbg(&cdev->device, "cur_state=%ld\n", cur_state); |
e151a202 | 64 | |
3dbfff3d ZR |
65 | switch (trend) { |
66 | case THERMAL_TREND_RAISING: | |
e79fe642 | 67 | if (throttle) { |
ca56caa0 | 68 | next_target = cur_state < instance->upper ? |
3dbfff3d | 69 | (cur_state + 1) : instance->upper; |
ca56caa0 EV |
70 | if (next_target < instance->lower) |
71 | next_target = instance->lower; | |
e79fe642 | 72 | } |
3dbfff3d ZR |
73 | break; |
74 | case THERMAL_TREND_RAISE_FULL: | |
75 | if (throttle) | |
ca56caa0 | 76 | next_target = instance->upper; |
3dbfff3d ZR |
77 | break; |
78 | case THERMAL_TREND_DROPPING: | |
79 | if (cur_state == instance->lower) { | |
80 | if (!throttle) | |
ca56caa0 | 81 | next_target = THERMAL_NO_TARGET; |
e79fe642 | 82 | } else { |
ca56caa0 EV |
83 | next_target = cur_state - 1; |
84 | if (next_target > instance->upper) | |
85 | next_target = instance->upper; | |
e79fe642 | 86 | } |
3dbfff3d ZR |
87 | break; |
88 | case THERMAL_TREND_DROP_FULL: | |
89 | if (cur_state == instance->lower) { | |
90 | if (!throttle) | |
ca56caa0 | 91 | next_target = THERMAL_NO_TARGET; |
3dbfff3d | 92 | } else |
ca56caa0 | 93 | next_target = instance->lower; |
3dbfff3d ZR |
94 | break; |
95 | default: | |
96 | break; | |
e151a202 D |
97 | } |
98 | ||
ca56caa0 | 99 | return next_target; |
e151a202 D |
100 | } |
101 | ||
102 | static void update_passive_instance(struct thermal_zone_device *tz, | |
103 | enum thermal_trip_type type, int value) | |
104 | { | |
105 | /* | |
106 | * If value is +1, activate a passive instance. | |
107 | * If value is -1, deactivate a passive instance. | |
108 | */ | |
109 | if (type == THERMAL_TRIP_PASSIVE || type == THERMAL_TRIPS_NONE) | |
110 | tz->passive += value; | |
111 | } | |
112 | ||
e151a202 D |
113 | static void thermal_zone_trip_update(struct thermal_zone_device *tz, int trip) |
114 | { | |
115 | long trip_temp; | |
116 | enum thermal_trip_type trip_type; | |
117 | enum thermal_trend trend; | |
b8bb6cb9 ZR |
118 | struct thermal_instance *instance; |
119 | bool throttle = false; | |
120 | int old_target; | |
e151a202 D |
121 | |
122 | if (trip == THERMAL_TRIPS_NONE) { | |
123 | trip_temp = tz->forced_passive; | |
124 | trip_type = THERMAL_TRIPS_NONE; | |
125 | } else { | |
126 | tz->ops->get_trip_temp(tz, trip, &trip_temp); | |
127 | tz->ops->get_trip_type(tz, trip, &trip_type); | |
128 | } | |
129 | ||
130 | trend = get_tz_trend(tz, trip); | |
131 | ||
b8bb6cb9 ZR |
132 | if (tz->temperature >= trip_temp) |
133 | throttle = true; | |
134 | ||
06475b55 AL |
135 | dev_dbg(&tz->device, "Trip%d[type=%d,temp=%ld]:trend=%d,throttle=%d\n", |
136 | trip, trip_type, trip_temp, trend, throttle); | |
137 | ||
e151a202 D |
138 | mutex_lock(&tz->lock); |
139 | ||
b8bb6cb9 ZR |
140 | list_for_each_entry(instance, &tz->thermal_instances, tz_node) { |
141 | if (instance->trip != trip) | |
142 | continue; | |
143 | ||
144 | old_target = instance->target; | |
145 | instance->target = get_target_state(instance, trend, throttle); | |
06475b55 AL |
146 | dev_dbg(&instance->cdev->device, "old_target=%d, target=%d\n", |
147 | old_target, (int)instance->target); | |
b8bb6cb9 | 148 | |
178c2490 SG |
149 | if (old_target == instance->target) |
150 | continue; | |
151 | ||
b8bb6cb9 ZR |
152 | /* Activate a passive thermal instance */ |
153 | if (old_target == THERMAL_NO_TARGET && | |
154 | instance->target != THERMAL_NO_TARGET) | |
155 | update_passive_instance(tz, trip_type, 1); | |
156 | /* Deactivate a passive thermal instance */ | |
157 | else if (old_target != THERMAL_NO_TARGET && | |
158 | instance->target == THERMAL_NO_TARGET) | |
159 | update_passive_instance(tz, trip_type, -1); | |
160 | ||
161 | ||
162 | instance->cdev->updated = false; /* cdev needs update */ | |
163 | } | |
e151a202 D |
164 | |
165 | mutex_unlock(&tz->lock); | |
166 | } | |
167 | ||
168 | /** | |
169 | * step_wise_throttle - throttles devices asscciated with the given zone | |
170 | * @tz - thermal_zone_device | |
171 | * @trip - the trip point | |
172 | * @trip_type - type of the trip point | |
173 | * | |
174 | * Throttling Logic: This uses the trend of the thermal zone to throttle. | |
175 | * If the thermal zone is 'heating up' this throttles all the cooling | |
176 | * devices associated with the zone and its particular trip point, by one | |
177 | * step. If the zone is 'cooling down' it brings back the performance of | |
178 | * the devices by one step. | |
179 | */ | |
b88a4977 | 180 | static int step_wise_throttle(struct thermal_zone_device *tz, int trip) |
e151a202 D |
181 | { |
182 | struct thermal_instance *instance; | |
183 | ||
184 | thermal_zone_trip_update(tz, trip); | |
185 | ||
186 | if (tz->forced_passive) | |
187 | thermal_zone_trip_update(tz, THERMAL_TRIPS_NONE); | |
188 | ||
189 | mutex_lock(&tz->lock); | |
190 | ||
191 | list_for_each_entry(instance, &tz->thermal_instances, tz_node) | |
192 | thermal_cdev_update(instance->cdev); | |
193 | ||
194 | mutex_unlock(&tz->lock); | |
195 | ||
196 | return 0; | |
197 | } | |
198 | ||
b88a4977 | 199 | static struct thermal_governor thermal_gov_step_wise = { |
1f53ef17 | 200 | .name = "step_wise", |
e151a202 | 201 | .throttle = step_wise_throttle, |
e151a202 D |
202 | }; |
203 | ||
80a26a5c | 204 | int thermal_gov_step_wise_register(void) |
e151a202 D |
205 | { |
206 | return thermal_register_governor(&thermal_gov_step_wise); | |
207 | } | |
208 | ||
80a26a5c | 209 | void thermal_gov_step_wise_unregister(void) |
e151a202 D |
210 | { |
211 | thermal_unregister_governor(&thermal_gov_step_wise); | |
212 | } |