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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 | |
38 | */ | |
39 | static unsigned long get_target_state(struct thermal_instance *instance, | |
40 | enum thermal_trend trend) | |
41 | { | |
42 | struct thermal_cooling_device *cdev = instance->cdev; | |
43 | unsigned long cur_state; | |
44 | ||
45 | cdev->ops->get_cur_state(cdev, &cur_state); | |
46 | ||
47 | if (trend == THERMAL_TREND_RAISING) { | |
48 | cur_state = cur_state < instance->upper ? | |
49 | (cur_state + 1) : instance->upper; | |
50 | } else if (trend == THERMAL_TREND_DROPPING) { | |
51 | cur_state = cur_state > instance->lower ? | |
52 | (cur_state - 1) : instance->lower; | |
53 | } | |
54 | ||
55 | return cur_state; | |
56 | } | |
57 | ||
58 | static void update_passive_instance(struct thermal_zone_device *tz, | |
59 | enum thermal_trip_type type, int value) | |
60 | { | |
61 | /* | |
62 | * If value is +1, activate a passive instance. | |
63 | * If value is -1, deactivate a passive instance. | |
64 | */ | |
65 | if (type == THERMAL_TRIP_PASSIVE || type == THERMAL_TRIPS_NONE) | |
66 | tz->passive += value; | |
67 | } | |
68 | ||
69 | static void update_instance_for_throttle(struct thermal_zone_device *tz, | |
70 | int trip, enum thermal_trip_type trip_type, | |
71 | enum thermal_trend trend) | |
72 | { | |
73 | struct thermal_instance *instance; | |
74 | ||
75 | list_for_each_entry(instance, &tz->thermal_instances, tz_node) { | |
76 | if (instance->trip != trip) | |
77 | continue; | |
78 | ||
79 | instance->target = get_target_state(instance, trend); | |
80 | ||
81 | /* Activate a passive thermal instance */ | |
82 | if (instance->target == THERMAL_NO_TARGET) | |
83 | update_passive_instance(tz, trip_type, 1); | |
84 | ||
85 | instance->cdev->updated = false; /* cdev needs update */ | |
86 | } | |
87 | } | |
88 | ||
89 | static void update_instance_for_dethrottle(struct thermal_zone_device *tz, | |
90 | int trip, enum thermal_trip_type trip_type) | |
91 | { | |
92 | struct thermal_instance *instance; | |
93 | struct thermal_cooling_device *cdev; | |
94 | unsigned long cur_state; | |
95 | ||
96 | list_for_each_entry(instance, &tz->thermal_instances, tz_node) { | |
97 | if (instance->trip != trip || | |
98 | instance->target == THERMAL_NO_TARGET) | |
99 | continue; | |
100 | ||
101 | cdev = instance->cdev; | |
102 | cdev->ops->get_cur_state(cdev, &cur_state); | |
103 | ||
104 | instance->target = cur_state > instance->lower ? | |
105 | (cur_state - 1) : THERMAL_NO_TARGET; | |
106 | ||
107 | /* Deactivate a passive thermal instance */ | |
108 | if (instance->target == THERMAL_NO_TARGET) | |
109 | update_passive_instance(tz, trip_type, -1); | |
110 | ||
111 | cdev->updated = false; /* cdev needs update */ | |
112 | } | |
113 | } | |
114 | ||
115 | static void thermal_zone_trip_update(struct thermal_zone_device *tz, int trip) | |
116 | { | |
117 | long trip_temp; | |
118 | enum thermal_trip_type trip_type; | |
119 | enum thermal_trend trend; | |
120 | ||
121 | if (trip == THERMAL_TRIPS_NONE) { | |
122 | trip_temp = tz->forced_passive; | |
123 | trip_type = THERMAL_TRIPS_NONE; | |
124 | } else { | |
125 | tz->ops->get_trip_temp(tz, trip, &trip_temp); | |
126 | tz->ops->get_trip_type(tz, trip, &trip_type); | |
127 | } | |
128 | ||
129 | trend = get_tz_trend(tz, trip); | |
130 | ||
131 | mutex_lock(&tz->lock); | |
132 | ||
133 | if (tz->temperature >= trip_temp) | |
134 | update_instance_for_throttle(tz, trip, trip_type, trend); | |
135 | else | |
136 | update_instance_for_dethrottle(tz, trip, trip_type); | |
137 | ||
138 | mutex_unlock(&tz->lock); | |
139 | } | |
140 | ||
141 | /** | |
142 | * step_wise_throttle - throttles devices asscciated with the given zone | |
143 | * @tz - thermal_zone_device | |
144 | * @trip - the trip point | |
145 | * @trip_type - type of the trip point | |
146 | * | |
147 | * Throttling Logic: This uses the trend of the thermal zone to throttle. | |
148 | * If the thermal zone is 'heating up' this throttles all the cooling | |
149 | * devices associated with the zone and its particular trip point, by one | |
150 | * step. If the zone is 'cooling down' it brings back the performance of | |
151 | * the devices by one step. | |
152 | */ | |
b88a4977 | 153 | static int step_wise_throttle(struct thermal_zone_device *tz, int trip) |
e151a202 D |
154 | { |
155 | struct thermal_instance *instance; | |
156 | ||
157 | thermal_zone_trip_update(tz, trip); | |
158 | ||
159 | if (tz->forced_passive) | |
160 | thermal_zone_trip_update(tz, THERMAL_TRIPS_NONE); | |
161 | ||
162 | mutex_lock(&tz->lock); | |
163 | ||
164 | list_for_each_entry(instance, &tz->thermal_instances, tz_node) | |
165 | thermal_cdev_update(instance->cdev); | |
166 | ||
167 | mutex_unlock(&tz->lock); | |
168 | ||
169 | return 0; | |
170 | } | |
171 | ||
b88a4977 | 172 | static struct thermal_governor thermal_gov_step_wise = { |
e151a202 D |
173 | .name = DEFAULT_THERMAL_GOVERNOR, |
174 | .throttle = step_wise_throttle, | |
175 | .owner = THIS_MODULE, | |
176 | }; | |
177 | ||
178 | static int __init thermal_gov_step_wise_init(void) | |
179 | { | |
180 | return thermal_register_governor(&thermal_gov_step_wise); | |
181 | } | |
182 | ||
183 | static void __exit thermal_gov_step_wise_exit(void) | |
184 | { | |
185 | thermal_unregister_governor(&thermal_gov_step_wise); | |
186 | } | |
187 | ||
188 | /* This should load after thermal framework */ | |
189 | fs_initcall(thermal_gov_step_wise_init); | |
190 | module_exit(thermal_gov_step_wise_exit); | |
191 | ||
192 | MODULE_AUTHOR("Durgadoss R"); | |
193 | MODULE_DESCRIPTION("A step-by-step thermal throttling governor"); | |
194 | MODULE_LICENSE("GPL"); |