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
|
/*
* ledtrig-cpu.c - LED trigger based on CPU activity
*
* This LED trigger will be registered for each possible CPU and named as
* cpu0, cpu1, cpu2, cpu3, etc.
*
* It can be bound to any LED just like other triggers using either a
* board file or via sysfs interface.
*
* An API named ledtrig_cpu is exported for any user, who want to add CPU
* activity indication in their code
*
* Copyright 2011 Linus Walleij <linus.walleij@linaro.org>
* Copyright 2011 - 2012 Bryan Wu <bryan.wu@canonical.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/percpu.h>
#include <linux/syscore_ops.h>
#include <linux/rwsem.h>
#include <linux/cpu.h>
#include "../leds.h"
#define MAX_NAME_LEN 8
struct led_trigger_cpu {
char name[MAX_NAME_LEN];
struct led_trigger *_trig;
};
static DEFINE_PER_CPU(struct led_trigger_cpu, cpu_trig);
/**
* ledtrig_cpu - emit a CPU event as a trigger
* @evt: CPU event to be emitted
*
* Emit a CPU event on a CPU core, which will trigger a
* binded LED to turn on or turn off.
*/
void ledtrig_cpu(enum cpu_led_event ledevt)
{
struct led_trigger_cpu *trig = this_cpu_ptr(&cpu_trig);
/* Locate the correct CPU LED */
switch (ledevt) {
case CPU_LED_IDLE_END:
case CPU_LED_START:
/* Will turn the LED on, max brightness */
led_trigger_event(trig->_trig, LED_FULL);
break;
case CPU_LED_IDLE_START:
case CPU_LED_STOP:
case CPU_LED_HALTED:
/* Will turn the LED off */
led_trigger_event(trig->_trig, LED_OFF);
break;
default:
/* Will leave the LED as it is */
break;
}
}
EXPORT_SYMBOL(ledtrig_cpu);
static int ledtrig_cpu_syscore_suspend(void)
{
ledtrig_cpu(CPU_LED_STOP);
return 0;
}
static void ledtrig_cpu_syscore_resume(void)
{
ledtrig_cpu(CPU_LED_START);
}
static void ledtrig_cpu_syscore_shutdown(void)
{
ledtrig_cpu(CPU_LED_HALTED);
}
static struct syscore_ops ledtrig_cpu_syscore_ops = {
.shutdown = ledtrig_cpu_syscore_shutdown,
.suspend = ledtrig_cpu_syscore_suspend,
.resume = ledtrig_cpu_syscore_resume,
};
static int ledtrig_cpu_notify(struct notifier_block *self,
unsigned long action, void *hcpu)
{
switch (action & ~CPU_TASKS_FROZEN) {
case CPU_STARTING:
ledtrig_cpu(CPU_LED_START);
break;
case CPU_DYING:
ledtrig_cpu(CPU_LED_STOP);
break;
}
return NOTIFY_OK;
}
static struct notifier_block ledtrig_cpu_nb = {
.notifier_call = ledtrig_cpu_notify,
};
static int __init ledtrig_cpu_init(void)
{
int cpu;
/* Supports up to 9999 cpu cores */
BUILD_BUG_ON(CONFIG_NR_CPUS > 9999);
/*
* Registering CPU led trigger for each CPU core here
* ignores CPU hotplug, but after this CPU hotplug works
* fine with this trigger.
*/
for_each_possible_cpu(cpu) {
struct led_trigger_cpu *trig = &per_cpu(cpu_trig, cpu);
snprintf(trig->name, MAX_NAME_LEN, "cpu%d", cpu);
led_trigger_register_simple(trig->name, &trig->_trig);
}
register_syscore_ops(&ledtrig_cpu_syscore_ops);
register_cpu_notifier(&ledtrig_cpu_nb);
pr_info("ledtrig-cpu: registered to indicate activity on CPUs\n");
return 0;
}
device_initcall(ledtrig_cpu_init);
|
