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 <pavel@ucw.cz> |
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 | |
23 | static unsigned long suspend_test_start_time; |
24 | static u32 test_repeat_count_max = 1; |
25 | static u32 test_repeat_count_current; |
26 | |
27 | void 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 | |
36 | void 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 | |
62 | static 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 */ |
78 | repeat: |
79 | status = rtc_read_time(rtc, tm: &alm.time); |
80 | if (status < 0) { |
81 | printk(err_readtime, dev_name(&rtc->dev), status); |
82 | return; |
83 | } |
84 | now = rtc_tm_to_time64(tm: &alm.time); |
85 | |
86 | memset(&alm, 0, sizeof alm); |
87 | rtc_time64_to_tm(time: now + TEST_SUSPEND_SECONDS, tm: &alm.time); |
88 | alm.enabled = true; |
89 | |
90 | status = rtc_set_alarm(rtc, alrm: &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, alrm: &alm); |
126 | } |
127 | |
128 | static 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(dev: 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 | */ |
145 | static const char *test_state_label __initdata; |
146 | |
147 | static char warn_bad_state[] __initdata = |
148 | KERN_WARNING "PM: can't test '%s' suspend state\n" ; |
149 | |
150 | static 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(s: repeat, base: 0, res: &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 | |
179 | static 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(class: rtc_class, NULL, NULL, match: has_wakealarm); |
205 | if (dev) { |
206 | rtc = rtc_class_open(name: 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, state: test_state); |
216 | rtc_class_close(rtc); |
217 | return 0; |
218 | } |
219 | late_initcall(test_suspend); |
220 | |