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4ccc5743 D |
1 | /* |
2 | * fair_share.c - A simple weight based Thermal 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 | ||
4ccc5743 | 25 | #include <linux/thermal.h> |
208cd822 | 26 | #include <trace/events/thermal.h> |
4ccc5743 D |
27 | |
28 | #include "thermal_core.h" | |
29 | ||
30 | /** | |
31 | * get_trip_level: - obtains the current trip level for a zone | |
32 | * @tz: thermal zone device | |
33 | */ | |
34 | static int get_trip_level(struct thermal_zone_device *tz) | |
35 | { | |
36 | int count = 0; | |
17e8351a | 37 | int trip_temp; |
208cd822 | 38 | enum thermal_trip_type trip_type; |
4ccc5743 D |
39 | |
40 | if (tz->trips == 0 || !tz->ops->get_trip_temp) | |
41 | return 0; | |
42 | ||
43 | for (count = 0; count < tz->trips; count++) { | |
44 | tz->ops->get_trip_temp(tz, count, &trip_temp); | |
45 | if (tz->temperature < trip_temp) | |
46 | break; | |
47 | } | |
208cd822 PA |
48 | |
49 | /* | |
50 | * count > 0 only if temperature is greater than first trip | |
51 | * point, in which case, trip_point = count - 1 | |
52 | */ | |
53 | if (count > 0) { | |
54 | tz->ops->get_trip_type(tz, count - 1, &trip_type); | |
55 | trace_thermal_zone_trip(tz, count - 1, trip_type); | |
56 | } | |
57 | ||
4ccc5743 D |
58 | return count; |
59 | } | |
60 | ||
61 | static long get_target_state(struct thermal_zone_device *tz, | |
bcdcbbc7 | 62 | struct thermal_cooling_device *cdev, int percentage, int level) |
4ccc5743 D |
63 | { |
64 | unsigned long max_state; | |
65 | ||
66 | cdev->ops->get_max_state(cdev, &max_state); | |
67 | ||
bcdcbbc7 | 68 | return (long)(percentage * level * max_state) / (100 * tz->trips); |
4ccc5743 D |
69 | } |
70 | ||
71 | /** | |
80b89172 | 72 | * fair_share_throttle - throttles devices associated with the given zone |
4ccc5743 D |
73 | * @tz - thermal_zone_device |
74 | * | |
75 | * Throttling Logic: This uses three parameters to calculate the new | |
76 | * throttle state of the cooling devices associated with the given zone. | |
77 | * | |
78 | * Parameters used for Throttling: | |
79 | * P1. max_state: Maximum throttle state exposed by the cooling device. | |
bcdcbbc7 | 80 | * P2. percentage[i]/100: |
4ccc5743 D |
81 | * How 'effective' the 'i'th device is, in cooling the given zone. |
82 | * P3. cur_trip_level/max_no_of_trips: | |
83 | * This describes the extent to which the devices should be throttled. | |
84 | * We do not want to throttle too much when we trip a lower temperature, | |
85 | * whereas the throttling is at full swing if we trip critical levels. | |
86 | * (Heavily assumes the trip points are in ascending order) | |
87 | * new_state of cooling device = P3 * P2 * P1 | |
88 | */ | |
62176933 | 89 | static int fair_share_throttle(struct thermal_zone_device *tz, int trip) |
4ccc5743 | 90 | { |
4ccc5743 | 91 | struct thermal_instance *instance; |
bcdcbbc7 JM |
92 | int total_weight = 0; |
93 | int total_instance = 0; | |
4ccc5743 D |
94 | int cur_trip_level = get_trip_level(tz); |
95 | ||
8b91e2cb | 96 | list_for_each_entry(instance, &tz->thermal_instances, tz_node) { |
bcdcbbc7 JM |
97 | if (instance->trip != trip) |
98 | continue; | |
99 | ||
100 | total_weight += instance->weight; | |
101 | total_instance++; | |
102 | } | |
103 | ||
104 | list_for_each_entry(instance, &tz->thermal_instances, tz_node) { | |
105 | int percentage; | |
8b91e2cb | 106 | struct thermal_cooling_device *cdev = instance->cdev; |
4ccc5743 | 107 | |
8b91e2cb | 108 | if (instance->trip != trip) |
4ccc5743 D |
109 | continue; |
110 | ||
bcdcbbc7 JM |
111 | if (!total_weight) |
112 | percentage = 100 / total_instance; | |
113 | else | |
114 | percentage = (instance->weight * 100) / total_weight; | |
115 | ||
116 | instance->target = get_target_state(tz, cdev, percentage, | |
117 | cur_trip_level); | |
4ccc5743 D |
118 | |
119 | instance->cdev->updated = false; | |
120 | thermal_cdev_update(cdev); | |
121 | } | |
122 | return 0; | |
123 | } | |
124 | ||
62176933 | 125 | static struct thermal_governor thermal_gov_fair_share = { |
4ccc5743 D |
126 | .name = "fair_share", |
127 | .throttle = fair_share_throttle, | |
4ccc5743 D |
128 | }; |
129 | ||
80a26a5c | 130 | int thermal_gov_fair_share_register(void) |
4ccc5743 D |
131 | { |
132 | return thermal_register_governor(&thermal_gov_fair_share); | |
133 | } | |
134 | ||
80a26a5c | 135 | void thermal_gov_fair_share_unregister(void) |
4ccc5743 D |
136 | { |
137 | thermal_unregister_governor(&thermal_gov_fair_share); | |
138 | } | |
139 |