blob: 869976d1b734e845d972d942917ea15faf45357d [file] [log] [blame]
Thomas Gleixnerd2912cb2019-06-04 10:11:33 +02001// SPDX-License-Identifier: GPL-2.0-only
Bryan Wu8f887312011-06-25 18:33:50 +08002/*
3 * ledtrig-cpu.c - LED trigger based on CPU activity
4 *
5 * This LED trigger will be registered for each possible CPU and named as
6 * cpu0, cpu1, cpu2, cpu3, etc.
7 *
8 * It can be bound to any LED just like other triggers using either a
9 * board file or via sysfs interface.
10 *
11 * An API named ledtrig_cpu is exported for any user, who want to add CPU
12 * activity indication in their code
13 *
14 * Copyright 2011 Linus Walleij <linus.walleij@linaro.org>
15 * Copyright 2011 - 2012 Bryan Wu <bryan.wu@canonical.com>
Bryan Wu8f887312011-06-25 18:33:50 +080016 */
17
Bryan Wu8f887312011-06-25 18:33:50 +080018#include <linux/kernel.h>
19#include <linux/init.h>
20#include <linux/slab.h>
21#include <linux/percpu.h>
22#include <linux/syscore_ops.h>
23#include <linux/rwsem.h>
Pawel Mollfba14ae2014-01-22 08:32:02 -080024#include <linux/cpu.h>
Kim, Milof07fb522013-02-20 00:36:01 -080025#include "../leds.h"
Bryan Wu8f887312011-06-25 18:33:50 +080026
27#define MAX_NAME_LEN 8
28
29struct led_trigger_cpu {
Paulo Costa0b88b712017-02-09 21:07:35 -020030 bool is_active;
Bryan Wu8f887312011-06-25 18:33:50 +080031 char name[MAX_NAME_LEN];
32 struct led_trigger *_trig;
Bryan Wu8f887312011-06-25 18:33:50 +080033};
34
35static DEFINE_PER_CPU(struct led_trigger_cpu, cpu_trig);
36
Paulo Costa0b88b712017-02-09 21:07:35 -020037static struct led_trigger *trig_cpu_all;
38static atomic_t num_active_cpus = ATOMIC_INIT(0);
39
Bryan Wu8f887312011-06-25 18:33:50 +080040/**
41 * ledtrig_cpu - emit a CPU event as a trigger
42 * @evt: CPU event to be emitted
43 *
44 * Emit a CPU event on a CPU core, which will trigger a
Pavel Macheke602fda2016-10-03 10:13:14 +020045 * bound LED to turn on or turn off.
Bryan Wu8f887312011-06-25 18:33:50 +080046 */
47void ledtrig_cpu(enum cpu_led_event ledevt)
48{
Christoph Lameter24c93012014-05-05 09:48:38 -070049 struct led_trigger_cpu *trig = this_cpu_ptr(&cpu_trig);
Paulo Costa0b88b712017-02-09 21:07:35 -020050 bool is_active = trig->is_active;
Bryan Wu8f887312011-06-25 18:33:50 +080051
Bryan Wu8f887312011-06-25 18:33:50 +080052 /* Locate the correct CPU LED */
53 switch (ledevt) {
54 case CPU_LED_IDLE_END:
55 case CPU_LED_START:
56 /* Will turn the LED on, max brightness */
Paulo Costa0b88b712017-02-09 21:07:35 -020057 is_active = true;
Bryan Wu8f887312011-06-25 18:33:50 +080058 break;
59
60 case CPU_LED_IDLE_START:
61 case CPU_LED_STOP:
62 case CPU_LED_HALTED:
63 /* Will turn the LED off */
Paulo Costa0b88b712017-02-09 21:07:35 -020064 is_active = false;
Bryan Wu8f887312011-06-25 18:33:50 +080065 break;
66
67 default:
68 /* Will leave the LED as it is */
69 break;
70 }
Paulo Costa0b88b712017-02-09 21:07:35 -020071
72 if (is_active != trig->is_active) {
73 unsigned int active_cpus;
74 unsigned int total_cpus;
75
76 /* Update trigger state */
77 trig->is_active = is_active;
78 atomic_add(is_active ? 1 : -1, &num_active_cpus);
79 active_cpus = atomic_read(&num_active_cpus);
80 total_cpus = num_present_cpus();
81
82 led_trigger_event(trig->_trig,
83 is_active ? LED_FULL : LED_OFF);
84
85
86 led_trigger_event(trig_cpu_all,
87 DIV_ROUND_UP(LED_FULL * active_cpus, total_cpus));
88
89 }
Bryan Wu8f887312011-06-25 18:33:50 +080090}
91EXPORT_SYMBOL(ledtrig_cpu);
92
93static int ledtrig_cpu_syscore_suspend(void)
94{
95 ledtrig_cpu(CPU_LED_STOP);
96 return 0;
97}
98
99static void ledtrig_cpu_syscore_resume(void)
100{
101 ledtrig_cpu(CPU_LED_START);
102}
103
104static void ledtrig_cpu_syscore_shutdown(void)
105{
106 ledtrig_cpu(CPU_LED_HALTED);
107}
108
109static struct syscore_ops ledtrig_cpu_syscore_ops = {
110 .shutdown = ledtrig_cpu_syscore_shutdown,
111 .suspend = ledtrig_cpu_syscore_suspend,
112 .resume = ledtrig_cpu_syscore_resume,
113};
114
Sebastian Andrzej Siewiorcd894f12016-07-20 17:24:55 +0200115static int ledtrig_online_cpu(unsigned int cpu)
Pawel Mollfba14ae2014-01-22 08:32:02 -0800116{
Richard Cochran911a3592016-07-13 17:16:45 +0000117 ledtrig_cpu(CPU_LED_START);
118 return 0;
Pawel Mollfba14ae2014-01-22 08:32:02 -0800119}
120
Sebastian Andrzej Siewiorcd894f12016-07-20 17:24:55 +0200121static int ledtrig_prepare_down_cpu(unsigned int cpu)
Richard Cochran911a3592016-07-13 17:16:45 +0000122{
123 ledtrig_cpu(CPU_LED_STOP);
124 return 0;
125}
Pawel Mollfba14ae2014-01-22 08:32:02 -0800126
Bryan Wu8f887312011-06-25 18:33:50 +0800127static int __init ledtrig_cpu_init(void)
128{
129 int cpu;
Sebastian Andrzej Siewiorcd894f12016-07-20 17:24:55 +0200130 int ret;
Bryan Wu8f887312011-06-25 18:33:50 +0800131
132 /* Supports up to 9999 cpu cores */
133 BUILD_BUG_ON(CONFIG_NR_CPUS > 9999);
134
135 /*
Paulo Costa0b88b712017-02-09 21:07:35 -0200136 * Registering a trigger for all CPUs.
137 */
138 led_trigger_register_simple("cpu", &trig_cpu_all);
139
140 /*
Bryan Wu8f887312011-06-25 18:33:50 +0800141 * Registering CPU led trigger for each CPU core here
142 * ignores CPU hotplug, but after this CPU hotplug works
143 * fine with this trigger.
144 */
145 for_each_possible_cpu(cpu) {
146 struct led_trigger_cpu *trig = &per_cpu(cpu_trig, cpu);
147
Bryan Wu8f887312011-06-25 18:33:50 +0800148 snprintf(trig->name, MAX_NAME_LEN, "cpu%d", cpu);
149
Bryan Wu8f887312011-06-25 18:33:50 +0800150 led_trigger_register_simple(trig->name, &trig->_trig);
Bryan Wu8f887312011-06-25 18:33:50 +0800151 }
152
153 register_syscore_ops(&ledtrig_cpu_syscore_ops);
Richard Cochran911a3592016-07-13 17:16:45 +0000154
Thomas Gleixner73c1b412016-12-21 20:19:54 +0100155 ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "leds/trigger:starting",
Sebastian Andrzej Siewiorcd894f12016-07-20 17:24:55 +0200156 ledtrig_online_cpu, ledtrig_prepare_down_cpu);
157 if (ret < 0)
158 pr_err("CPU hotplug notifier for ledtrig-cpu could not be registered: %d\n",
159 ret);
Bryan Wu8f887312011-06-25 18:33:50 +0800160
161 pr_info("ledtrig-cpu: registered to indicate activity on CPUs\n");
162
163 return 0;
164}
Paul Gortmaker227a0ca2015-12-13 16:45:49 -0500165device_initcall(ledtrig_cpu_init);