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, &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 } 127 128 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(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(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); 178 179 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(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 } 219 late_initcall(test_suspend); 220