1 /* 2 * kernel/power/suspend_test.c - Suspend to RAM and standby test facility. 3 * 4 * Copyright (c) 2009 Pavel Machek <pavel@ucw.cz> 5 * 6 * This file is released under the GPLv2. 7 */ 8 9 #include <linux/init.h> 10 #include <linux/rtc.h> 11 12 #include "power.h" 13 14 /* 15 * We test the system suspend code by setting an RTC wakealarm a short 16 * time in the future, then suspending. Suspending the devices won't 17 * normally take long ... some systems only need a few milliseconds. 18 * 19 * The time it takes is system-specific though, so when we test this 20 * during system bootup we allow a LOT of time. 21 */ 22 #define TEST_SUSPEND_SECONDS 10 23 24 static unsigned long suspend_test_start_time; 25 static u32 test_repeat_count_max = 1; 26 static u32 test_repeat_count_current; 27 28 void suspend_test_start(void) 29 { 30 /* FIXME Use better timebase than "jiffies", ideally a clocksource. 31 * What we want is a hardware counter that will work correctly even 32 * during the irqs-are-off stages of the suspend/resume cycle... 33 */ 34 suspend_test_start_time = jiffies; 35 } 36 37 void suspend_test_finish(const char *label) 38 { 39 long nj = jiffies - suspend_test_start_time; 40 unsigned msec; 41 42 msec = jiffies_to_msecs(abs(nj)); 43 pr_info("PM: %s took %d.%03d seconds\n", label, 44 msec / 1000, msec % 1000); 45 46 /* Warning on suspend means the RTC alarm period needs to be 47 * larger -- the system was sooo slooowwww to suspend that the 48 * alarm (should have) fired before the system went to sleep! 49 * 50 * Warning on either suspend or resume also means the system 51 * has some performance issues. The stack dump of a WARN_ON 52 * is more likely to get the right attention than a printk... 53 */ 54 WARN(msec > (TEST_SUSPEND_SECONDS * 1000), 55 "Component: %s, time: %u\n", label, msec); 56 } 57 58 /* 59 * To test system suspend, we need a hands-off mechanism to resume the 60 * system. RTCs wake alarms are a common self-contained mechanism. 61 */ 62 63 static void __init test_wakealarm(struct rtc_device *rtc, suspend_state_t state) 64 { 65 static char err_readtime[] __initdata = 66 KERN_ERR "PM: can't read %s time, err %d\n"; 67 static char err_wakealarm [] __initdata = 68 KERN_ERR "PM: can't set %s wakealarm, err %d\n"; 69 static char err_suspend[] __initdata = 70 KERN_ERR "PM: suspend test failed, error %d\n"; 71 static char info_test[] __initdata = 72 KERN_INFO "PM: test RTC wakeup from '%s' suspend\n"; 73 74 unsigned long now; 75 struct rtc_wkalrm alm; 76 int status; 77 78 /* this may fail if the RTC hasn't been initialized */ 79 repeat: 80 status = rtc_read_time(rtc, &alm.time); 81 if (status < 0) { 82 printk(err_readtime, dev_name(&rtc->dev), status); 83 return; 84 } 85 rtc_tm_to_time(&alm.time, &now); 86 87 memset(&alm, 0, sizeof alm); 88 rtc_time_to_tm(now + TEST_SUSPEND_SECONDS, &alm.time); 89 alm.enabled = true; 90 91 status = rtc_set_alarm(rtc, &alm); 92 if (status < 0) { 93 printk(err_wakealarm, dev_name(&rtc->dev), status); 94 return; 95 } 96 97 if (state == PM_SUSPEND_MEM) { 98 printk(info_test, pm_states[state]); 99 status = pm_suspend(state); 100 if (status == -ENODEV) 101 state = PM_SUSPEND_STANDBY; 102 } 103 if (state == PM_SUSPEND_STANDBY) { 104 printk(info_test, pm_states[state]); 105 status = pm_suspend(state); 106 if (status < 0) 107 state = PM_SUSPEND_FREEZE; 108 } 109 if (state == PM_SUSPEND_FREEZE) { 110 printk(info_test, pm_states[state]); 111 status = pm_suspend(state); 112 } 113 114 if (status < 0) 115 printk(err_suspend, status); 116 117 test_repeat_count_current++; 118 if (test_repeat_count_current < test_repeat_count_max) 119 goto repeat; 120 121 /* Some platforms can't detect that the alarm triggered the 122 * wakeup, or (accordingly) disable it after it afterwards. 123 * It's supposed to give oneshot behavior; cope. 124 */ 125 alm.enabled = false; 126 rtc_set_alarm(rtc, &alm); 127 } 128 129 static int __init has_wakealarm(struct device *dev, const void *data) 130 { 131 struct rtc_device *candidate = to_rtc_device(dev); 132 133 if (!candidate->ops->set_alarm) 134 return 0; 135 if (!device_may_wakeup(candidate->dev.parent)) 136 return 0; 137 138 return 1; 139 } 140 141 /* 142 * Kernel options like "test_suspend=mem" force suspend/resume sanity tests 143 * at startup time. They're normally disabled, for faster boot and because 144 * we can't know which states really work on this particular system. 145 */ 146 static const char *test_state_label __initdata; 147 148 static char warn_bad_state[] __initdata = 149 KERN_WARNING "PM: can't test '%s' suspend state\n"; 150 151 static int __init setup_test_suspend(char *value) 152 { 153 int i; 154 char *repeat; 155 char *suspend_type; 156 157 /* example : "=mem[,N]" ==> "mem[,N]" */ 158 value++; 159 suspend_type = strsep(&value, ","); 160 if (!suspend_type) 161 return 0; 162 163 repeat = strsep(&value, ","); 164 if (repeat) { 165 if (kstrtou32(repeat, 0, &test_repeat_count_max)) 166 return 0; 167 } 168 169 for (i = 0; pm_labels[i]; i++) 170 if (!strcmp(pm_labels[i], suspend_type)) { 171 test_state_label = pm_labels[i]; 172 return 0; 173 } 174 175 printk(warn_bad_state, suspend_type); 176 return 0; 177 } 178 __setup("test_suspend", setup_test_suspend); 179 180 static int __init test_suspend(void) 181 { 182 static char warn_no_rtc[] __initdata = 183 KERN_WARNING "PM: no wakealarm-capable RTC driver is ready\n"; 184 185 struct rtc_device *rtc = NULL; 186 struct device *dev; 187 suspend_state_t test_state; 188 189 /* PM is initialized by now; is that state testable? */ 190 if (!test_state_label) 191 return 0; 192 193 for (test_state = PM_SUSPEND_MIN; test_state < PM_SUSPEND_MAX; test_state++) { 194 const char *state_label = pm_states[test_state]; 195 196 if (state_label && !strcmp(test_state_label, state_label)) 197 break; 198 } 199 if (test_state == PM_SUSPEND_MAX) { 200 printk(warn_bad_state, test_state_label); 201 return 0; 202 } 203 204 /* RTCs have initialized by now too ... can we use one? */ 205 dev = class_find_device(rtc_class, NULL, NULL, has_wakealarm); 206 if (dev) 207 rtc = rtc_class_open(dev_name(dev)); 208 if (!rtc) { 209 printk(warn_no_rtc); 210 return 0; 211 } 212 213 /* go for it */ 214 test_wakealarm(rtc, test_state); 215 rtc_class_close(rtc); 216 return 0; 217 } 218 late_initcall(test_suspend); 219