1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
|
// SPDX-License-Identifier: GPL-2.0-only
/*
* step_wise.c - A step-by-step Thermal throttling governor
*
* Copyright (C) 2012 Intel Corp
* Copyright (C) 2012 Durgadoss R <durgadoss.r@intel.com>
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*/
#include <linux/thermal.h>
#include <linux/minmax.h>
#include "thermal_trace.h"
#include "thermal_core.h"
/*
* If the temperature is higher than a trip point,
* a. if the trend is THERMAL_TREND_RAISING, use higher cooling
* state for this trip point
* b. if the trend is THERMAL_TREND_DROPPING, use a lower cooling state
* for this trip point, but keep the cooling state above the applicable
* minimum
* If the temperature is lower than a trip point,
* a. if the trend is THERMAL_TREND_RAISING, do nothing
* b. if the trend is THERMAL_TREND_DROPPING, use the minimum applicable
* cooling state for this trip point, or if the cooling state already
* equals lower limit, deactivate the thermal instance
*/
static unsigned long get_target_state(struct thermal_instance *instance,
enum thermal_trend trend, bool throttle)
{
struct thermal_cooling_device *cdev = instance->cdev;
unsigned long cur_state;
/*
* We keep this instance the way it is by default.
* Otherwise, we use the current state of the
* cdev in use to determine the next_target.
*/
cdev->ops->get_cur_state(cdev, &cur_state);
dev_dbg(&cdev->device, "cur_state=%ld\n", cur_state);
if (!instance->initialized) {
if (throttle)
return clamp(cur_state + 1, instance->lower, instance->upper);
return THERMAL_NO_TARGET;
}
if (throttle) {
if (trend == THERMAL_TREND_RAISING)
return clamp(cur_state + 1, instance->lower, instance->upper);
/*
* If the zone temperature is falling, the cooling level can
* be reduced, but it should still be above the lower state of
* the given thermal instance to pull the temperature further
* down.
*/
if (trend == THERMAL_TREND_DROPPING)
return clamp(cur_state - 1,
min(instance->lower + 1, instance->upper),
instance->upper);
} else if (trend == THERMAL_TREND_DROPPING) {
if (cur_state <= instance->lower)
return THERMAL_NO_TARGET;
/*
* If 'throttle' is false, no mitigation is necessary, so
* request the lower state for this instance.
*/
return instance->lower;
}
return instance->target;
}
static void thermal_zone_trip_update(struct thermal_zone_device *tz,
const struct thermal_trip_desc *td,
int trip_threshold)
{
bool throttle = tz->temperature >= trip_threshold;
const struct thermal_trip *trip = &td->trip;
enum thermal_trend trend = get_tz_trend(tz, trip);
int trip_id = thermal_zone_trip_id(tz, trip);
struct thermal_instance *instance;
if (throttle)
trace_thermal_zone_trip(tz, trip_id, trip->type);
dev_dbg(&tz->device, "Trip%d[type=%d,temp=%d]:trend=%d,throttle=%d\n",
trip_id, trip->type, trip_threshold, trend, throttle);
list_for_each_entry(instance, &td->thermal_instances, trip_node) {
int old_target;
old_target = instance->target;
instance->target = get_target_state(instance, trend, throttle);
dev_dbg(&instance->cdev->device, "old_target=%d, target=%ld\n",
old_target, instance->target);
if (instance->initialized && old_target == instance->target)
continue;
instance->initialized = true;
scoped_guard(cooling_dev, instance->cdev) {
instance->cdev->updated = false; /* cdev needs update */
}
}
}
static void step_wise_manage(struct thermal_zone_device *tz)
{
const struct thermal_trip_desc *td;
struct thermal_instance *instance;
lockdep_assert_held(&tz->lock);
/*
* Throttling Logic: Use the trend of the thermal zone to throttle.
* If the thermal zone is 'heating up', throttle all of the cooling
* devices associated with each trip point by one step. If the zone
* is 'cooling down', it brings back the performance of the devices
* by one step.
*/
for_each_trip_desc(tz, td) {
const struct thermal_trip *trip = &td->trip;
if (trip->temperature == THERMAL_TEMP_INVALID ||
trip->type == THERMAL_TRIP_CRITICAL ||
trip->type == THERMAL_TRIP_HOT)
continue;
thermal_zone_trip_update(tz, td, td->threshold);
}
for_each_trip_desc(tz, td) {
list_for_each_entry(instance, &td->thermal_instances, trip_node)
thermal_cdev_update(instance->cdev);
}
}
static struct thermal_governor thermal_gov_step_wise = {
.name = "step_wise",
.manage = step_wise_manage,
};
THERMAL_GOVERNOR_DECLARE(thermal_gov_step_wise);
|
