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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * kernel/power/suspend_test.c - Suspend to RAM and standby test facility.
4 *
5 * Copyright (c) 2009 Pavel Machek <[email protected]>
6 */
7
8#include <linux/init.h>
9#include <linux/rtc.h>
10
11#include "power.h"
12
13/*
14 * We test the system suspend code by setting an RTC wakealarm a short
15 * time in the future, then suspending. Suspending the devices won't
16 * normally take long ... some systems only need a few milliseconds.
17 *
18 * The time it takes is system-specific though, so when we test this
19 * during system bootup we allow a LOT of time.
20 */
21#define TEST_SUSPEND_SECONDS 10
22
23static unsigned long suspend_test_start_time;
24static u32 test_repeat_count_max = 1;
25static u32 test_repeat_count_current;
26
27void suspend_test_start(void)
28{
29 /* FIXME Use better timebase than "jiffies", ideally a clocksource.
30 * What we want is a hardware counter that will work correctly even
31 * during the irqs-are-off stages of the suspend/resume cycle...
32 */
33 suspend_test_start_time = jiffies;
34}
35
36void suspend_test_finish(const char *label)
37{
38 long nj = jiffies - suspend_test_start_time;
39 unsigned msec;
40
41 msec = jiffies_to_msecs(abs(nj));
42 pr_info("PM: %s took %d.%03d seconds\n", label,
43 msec / 1000, msec % 1000);
44
45 /* Warning on suspend means the RTC alarm period needs to be
46 * larger -- the system was sooo slooowwww to suspend that the
47 * alarm (should have) fired before the system went to sleep!
48 *
49 * Warning on either suspend or resume also means the system
50 * has some performance issues. The stack dump of a WARN_ON
51 * is more likely to get the right attention than a printk...
52 */
53 WARN(msec > (TEST_SUSPEND_SECONDS * 1000),
54 "Component: %s, time: %u\n", label, msec);
55}
56
57/*
58 * To test system suspend, we need a hands-off mechanism to resume the
59 * system. RTCs wake alarms are a common self-contained mechanism.
60 */
61
62static void __init test_wakealarm(struct rtc_device *rtc, suspend_state_t state)
63{
64 static char err_readtime[] __initdata =
65 KERN_ERR "PM: can't read %s time, err %d\n";
66 static char err_wakealarm [] __initdata =
67 KERN_ERR "PM: can't set %s wakealarm, err %d\n";
68 static char err_suspend[] __initdata =
69 KERN_ERR "PM: suspend test failed, error %d\n";
70 static char info_test[] __initdata =
71 KERN_INFO "PM: test RTC wakeup from '%s' suspend\n";
72
73 time64_t now;
74 struct rtc_wkalrm alm;
75 int status;
76
77 /* this may fail if the RTC hasn't been initialized */
78repeat:
79 status = rtc_read_time(rtc, &alm.time);
80 if (status < 0) {
81 printk(err_readtime, dev_name(&rtc->dev), status);
82 return;
83 }
84 now = rtc_tm_to_time64(&alm.time);
85
86 memset(&alm, 0, sizeof alm);
87 rtc_time64_to_tm(now + TEST_SUSPEND_SECONDS, &alm.time);
88 alm.enabled = true;
89
90 status = rtc_set_alarm(rtc, &alm);
91 if (status < 0) {
92 printk(err_wakealarm, dev_name(&rtc->dev), status);
93 return;
94 }
95
96 if (state == PM_SUSPEND_MEM) {
97 printk(info_test, pm_states[state]);
98 status = pm_suspend(state);
99 if (status == -ENODEV)
100 state = PM_SUSPEND_STANDBY;
101 }
102 if (state == PM_SUSPEND_STANDBY) {
103 printk(info_test, pm_states[state]);
104 status = pm_suspend(state);
105 if (status < 0)
106 state = PM_SUSPEND_TO_IDLE;
107 }
108 if (state == PM_SUSPEND_TO_IDLE) {
109 printk(info_test, pm_states[state]);
110 status = pm_suspend(state);
111 }
112
113 if (status < 0)
114 printk(err_suspend, status);
115
116 test_repeat_count_current++;
117 if (test_repeat_count_current < test_repeat_count_max)
118 goto repeat;
119
120 /* Some platforms can't detect that the alarm triggered the
121 * wakeup, or (accordingly) disable it after it afterwards.
122 * It's supposed to give oneshot behavior; cope.
123 */
124 alm.enabled = false;
125 rtc_set_alarm(rtc, &alm);
126}
127
128static int __init has_wakealarm(struct device *dev, const void *data)
129{
130 struct rtc_device *candidate = to_rtc_device(dev);
131
132 if (!test_bit(RTC_FEATURE_ALARM, candidate->features))
133 return 0;
134 if (!device_may_wakeup(candidate->dev.parent))
135 return 0;
136
137 return 1;
138}
139
140/*
141 * Kernel options like "test_suspend=mem" force suspend/resume sanity tests
142 * at startup time. They're normally disabled, for faster boot and because
143 * we can't know which states really work on this particular system.
144 */
145static const char *test_state_label __initdata;
146
147static char warn_bad_state[] __initdata =
148 KERN_WARNING "PM: can't test '%s' suspend state\n";
149
150static int __init setup_test_suspend(char *value)
151{
152 int i;
153 char *repeat;
154 char *suspend_type;
155
156 /* example : "=mem[,N]" ==> "mem[,N]" */
157 value++;
158 suspend_type = strsep(&value, ",");
159 if (!suspend_type)
160 return 1;
161
162 repeat = strsep(&value, ",");
163 if (repeat) {
164 if (kstrtou32(repeat, 0, &test_repeat_count_max))
165 return 1;
166 }
167
168 for (i = PM_SUSPEND_MIN; i < PM_SUSPEND_MAX; i++)
169 if (!strcmp(pm_labels[i], suspend_type)) {
170 test_state_label = pm_labels[i];
171 return 1;
172 }
173
174 printk(warn_bad_state, suspend_type);
175 return 1;
176}
177__setup("test_suspend", setup_test_suspend);
178
179static int __init test_suspend(void)
180{
181 static char warn_no_rtc[] __initdata =
182 KERN_WARNING "PM: no wakealarm-capable RTC driver is ready\n";
183
184 struct rtc_device *rtc = NULL;
185 struct device *dev;
186 suspend_state_t test_state;
187
188 /* PM is initialized by now; is that state testable? */
189 if (!test_state_label)
190 return 0;
191
192 for (test_state = PM_SUSPEND_MIN; test_state < PM_SUSPEND_MAX; test_state++) {
193 const char *state_label = pm_states[test_state];
194
195 if (state_label && !strcmp(test_state_label, state_label))
196 break;
197 }
198 if (test_state == PM_SUSPEND_MAX) {
199 printk(warn_bad_state, test_state_label);
200 return 0;
201 }
202
203 /* RTCs have initialized by now too ... can we use one? */
204 dev = class_find_device(&rtc_class, NULL, NULL, has_wakealarm);
205 if (dev) {
206 rtc = rtc_class_open(dev_name(dev));
207 put_device(dev);
208 }
209 if (!rtc) {
210 printk(warn_no_rtc);
211 return 0;
212 }
213
214 /* go for it */
215 test_wakealarm(rtc, test_state);
216 rtc_class_close(rtc);
217 return 0;
218}
219late_initcall(test_suspend);