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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 | ||
25 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
26 | ||
27 | #include <linux/module.h> | |
28 | #include <linux/thermal.h> | |
29 | ||
30 | #include "thermal_core.h" | |
31 | ||
32 | /* | |
33 | * If the temperature is higher than a trip point, | |
34 | * a. if the trend is THERMAL_TREND_RAISING, use higher cooling | |
35 | * state for this trip point | |
36 | * b. if the trend is THERMAL_TREND_DROPPING, use lower cooling | |
37 | * state for this trip point | |
3dbfff3d ZR |
38 | * c. if the trend is THERMAL_TREND_RAISE_FULL, use upper limit |
39 | * for this trip point | |
40 | * d. if the trend is THERMAL_TREND_DROP_FULL, use lower limit | |
41 | * for this trip point | |
42 | * If the temperature is lower than a trip point, | |
43 | * a. if the trend is THERMAL_TREND_RAISING, do nothing | |
44 | * b. if the trend is THERMAL_TREND_DROPPING, use lower cooling | |
45 | * state for this trip point, if the cooling state already | |
46 | * equals lower limit, deactivate the thermal instance | |
47 | * c. if the trend is THERMAL_TREND_RAISE_FULL, do nothing | |
48 | * d. if the trend is THERMAL_TREND_DROP_FULL, use lower limit, | |
49 | * if the cooling state already equals lower limit, | |
50 | * deactive the thermal instance | |
e151a202 D |
51 | */ |
52 | static unsigned long get_target_state(struct thermal_instance *instance, | |
3dbfff3d | 53 | enum thermal_trend trend, bool throttle) |
e151a202 D |
54 | { |
55 | struct thermal_cooling_device *cdev = instance->cdev; | |
56 | unsigned long cur_state; | |
57 | ||
58 | cdev->ops->get_cur_state(cdev, &cur_state); | |
59 | ||
3dbfff3d ZR |
60 | switch (trend) { |
61 | case THERMAL_TREND_RAISING: | |
62 | if (throttle) | |
63 | cur_state = cur_state < instance->upper ? | |
64 | (cur_state + 1) : instance->upper; | |
65 | break; | |
66 | case THERMAL_TREND_RAISE_FULL: | |
67 | if (throttle) | |
68 | cur_state = instance->upper; | |
69 | break; | |
70 | case THERMAL_TREND_DROPPING: | |
71 | if (cur_state == instance->lower) { | |
72 | if (!throttle) | |
73 | cur_state = -1; | |
74 | } else | |
75 | cur_state -= 1; | |
76 | break; | |
77 | case THERMAL_TREND_DROP_FULL: | |
78 | if (cur_state == instance->lower) { | |
79 | if (!throttle) | |
80 | cur_state = -1; | |
81 | } else | |
82 | cur_state = instance->lower; | |
83 | break; | |
84 | default: | |
85 | break; | |
e151a202 D |
86 | } |
87 | ||
88 | return cur_state; | |
89 | } | |
90 | ||
91 | static void update_passive_instance(struct thermal_zone_device *tz, | |
92 | enum thermal_trip_type type, int value) | |
93 | { | |
94 | /* | |
95 | * If value is +1, activate a passive instance. | |
96 | * If value is -1, deactivate a passive instance. | |
97 | */ | |
98 | if (type == THERMAL_TRIP_PASSIVE || type == THERMAL_TRIPS_NONE) | |
99 | tz->passive += value; | |
100 | } | |
101 | ||
e151a202 D |
102 | static void thermal_zone_trip_update(struct thermal_zone_device *tz, int trip) |
103 | { | |
104 | long trip_temp; | |
105 | enum thermal_trip_type trip_type; | |
106 | enum thermal_trend trend; | |
b8bb6cb9 ZR |
107 | struct thermal_instance *instance; |
108 | bool throttle = false; | |
109 | int old_target; | |
e151a202 D |
110 | |
111 | if (trip == THERMAL_TRIPS_NONE) { | |
112 | trip_temp = tz->forced_passive; | |
113 | trip_type = THERMAL_TRIPS_NONE; | |
114 | } else { | |
115 | tz->ops->get_trip_temp(tz, trip, &trip_temp); | |
116 | tz->ops->get_trip_type(tz, trip, &trip_type); | |
117 | } | |
118 | ||
119 | trend = get_tz_trend(tz, trip); | |
120 | ||
b8bb6cb9 ZR |
121 | if (tz->temperature >= trip_temp) |
122 | throttle = true; | |
123 | ||
e151a202 D |
124 | mutex_lock(&tz->lock); |
125 | ||
b8bb6cb9 ZR |
126 | list_for_each_entry(instance, &tz->thermal_instances, tz_node) { |
127 | if (instance->trip != trip) | |
128 | continue; | |
129 | ||
130 | old_target = instance->target; | |
131 | instance->target = get_target_state(instance, trend, throttle); | |
132 | ||
133 | /* Activate a passive thermal instance */ | |
134 | if (old_target == THERMAL_NO_TARGET && | |
135 | instance->target != THERMAL_NO_TARGET) | |
136 | update_passive_instance(tz, trip_type, 1); | |
137 | /* Deactivate a passive thermal instance */ | |
138 | else if (old_target != THERMAL_NO_TARGET && | |
139 | instance->target == THERMAL_NO_TARGET) | |
140 | update_passive_instance(tz, trip_type, -1); | |
141 | ||
142 | ||
143 | instance->cdev->updated = false; /* cdev needs update */ | |
144 | } | |
e151a202 D |
145 | |
146 | mutex_unlock(&tz->lock); | |
147 | } | |
148 | ||
149 | /** | |
150 | * step_wise_throttle - throttles devices asscciated with the given zone | |
151 | * @tz - thermal_zone_device | |
152 | * @trip - the trip point | |
153 | * @trip_type - type of the trip point | |
154 | * | |
155 | * Throttling Logic: This uses the trend of the thermal zone to throttle. | |
156 | * If the thermal zone is 'heating up' this throttles all the cooling | |
157 | * devices associated with the zone and its particular trip point, by one | |
158 | * step. If the zone is 'cooling down' it brings back the performance of | |
159 | * the devices by one step. | |
160 | */ | |
b88a4977 | 161 | static int step_wise_throttle(struct thermal_zone_device *tz, int trip) |
e151a202 D |
162 | { |
163 | struct thermal_instance *instance; | |
164 | ||
165 | thermal_zone_trip_update(tz, trip); | |
166 | ||
167 | if (tz->forced_passive) | |
168 | thermal_zone_trip_update(tz, THERMAL_TRIPS_NONE); | |
169 | ||
170 | mutex_lock(&tz->lock); | |
171 | ||
172 | list_for_each_entry(instance, &tz->thermal_instances, tz_node) | |
173 | thermal_cdev_update(instance->cdev); | |
174 | ||
175 | mutex_unlock(&tz->lock); | |
176 | ||
177 | return 0; | |
178 | } | |
179 | ||
b88a4977 | 180 | static struct thermal_governor thermal_gov_step_wise = { |
1f53ef17 | 181 | .name = "step_wise", |
e151a202 D |
182 | .throttle = step_wise_throttle, |
183 | .owner = THIS_MODULE, | |
184 | }; | |
185 | ||
186 | static int __init thermal_gov_step_wise_init(void) | |
187 | { | |
188 | return thermal_register_governor(&thermal_gov_step_wise); | |
189 | } | |
190 | ||
191 | static void __exit thermal_gov_step_wise_exit(void) | |
192 | { | |
193 | thermal_unregister_governor(&thermal_gov_step_wise); | |
194 | } | |
195 | ||
196 | /* This should load after thermal framework */ | |
197 | fs_initcall(thermal_gov_step_wise_init); | |
198 | module_exit(thermal_gov_step_wise_exit); | |
199 | ||
200 | MODULE_AUTHOR("Durgadoss R"); | |
201 | MODULE_DESCRIPTION("A step-by-step thermal throttling governor"); | |
202 | MODULE_LICENSE("GPL"); |