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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 | ||
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 | * get_trip_level: - obtains the current trip level for a zone | |
34 | * @tz: thermal zone device | |
35 | */ | |
36 | static int get_trip_level(struct thermal_zone_device *tz) | |
37 | { | |
38 | int count = 0; | |
39 | unsigned long trip_temp; | |
40 | ||
41 | if (tz->trips == 0 || !tz->ops->get_trip_temp) | |
42 | return 0; | |
43 | ||
44 | for (count = 0; count < tz->trips; count++) { | |
45 | tz->ops->get_trip_temp(tz, count, &trip_temp); | |
46 | if (tz->temperature < trip_temp) | |
47 | break; | |
48 | } | |
49 | return count; | |
50 | } | |
51 | ||
52 | static long get_target_state(struct thermal_zone_device *tz, | |
53 | struct thermal_cooling_device *cdev, int weight, int level) | |
54 | { | |
55 | unsigned long max_state; | |
56 | ||
57 | cdev->ops->get_max_state(cdev, &max_state); | |
58 | ||
59 | return (long)(weight * level * max_state) / (100 * tz->trips); | |
60 | } | |
61 | ||
62 | /** | |
63 | * fair_share_throttle - throttles devices asscciated with the given zone | |
64 | * @tz - thermal_zone_device | |
65 | * | |
66 | * Throttling Logic: This uses three parameters to calculate the new | |
67 | * throttle state of the cooling devices associated with the given zone. | |
68 | * | |
69 | * Parameters used for Throttling: | |
70 | * P1. max_state: Maximum throttle state exposed by the cooling device. | |
71 | * P2. weight[i]/100: | |
72 | * How 'effective' the 'i'th device is, in cooling the given zone. | |
73 | * P3. cur_trip_level/max_no_of_trips: | |
74 | * This describes the extent to which the devices should be throttled. | |
75 | * We do not want to throttle too much when we trip a lower temperature, | |
76 | * whereas the throttling is at full swing if we trip critical levels. | |
77 | * (Heavily assumes the trip points are in ascending order) | |
78 | * new_state of cooling device = P3 * P2 * P1 | |
79 | */ | |
62176933 | 80 | static int fair_share_throttle(struct thermal_zone_device *tz, int trip) |
4ccc5743 D |
81 | { |
82 | const struct thermal_zone_params *tzp; | |
83 | struct thermal_cooling_device *cdev; | |
84 | struct thermal_instance *instance; | |
85 | int i; | |
86 | int cur_trip_level = get_trip_level(tz); | |
87 | ||
88 | if (!tz->tzp || !tz->tzp->tbp) | |
89 | return -EINVAL; | |
90 | ||
91 | tzp = tz->tzp; | |
92 | ||
93 | for (i = 0; i < tzp->num_tbps; i++) { | |
94 | if (!tzp->tbp[i].cdev) | |
95 | continue; | |
96 | ||
97 | cdev = tzp->tbp[i].cdev; | |
98 | instance = get_thermal_instance(tz, cdev, trip); | |
99 | if (!instance) | |
100 | continue; | |
101 | ||
102 | instance->target = get_target_state(tz, cdev, | |
103 | tzp->tbp[i].weight, cur_trip_level); | |
104 | ||
105 | instance->cdev->updated = false; | |
106 | thermal_cdev_update(cdev); | |
107 | } | |
108 | return 0; | |
109 | } | |
110 | ||
62176933 | 111 | static struct thermal_governor thermal_gov_fair_share = { |
4ccc5743 D |
112 | .name = "fair_share", |
113 | .throttle = fair_share_throttle, | |
114 | .owner = THIS_MODULE, | |
115 | }; | |
116 | ||
117 | static int __init thermal_gov_fair_share_init(void) | |
118 | { | |
119 | return thermal_register_governor(&thermal_gov_fair_share); | |
120 | } | |
121 | ||
122 | static void __exit thermal_gov_fair_share_exit(void) | |
123 | { | |
124 | thermal_unregister_governor(&thermal_gov_fair_share); | |
125 | } | |
126 | ||
127 | /* This should load after thermal framework */ | |
128 | fs_initcall(thermal_gov_fair_share_init); | |
129 | module_exit(thermal_gov_fair_share_exit); | |
130 | ||
131 | MODULE_AUTHOR("Durgadoss R"); | |
132 | MODULE_DESCRIPTION("A simple weight based thermal throttling governor"); | |
133 | MODULE_LICENSE("GPL"); |