/* * kernel/power/suspend_test.c - Suspend to RAM and standby test facility. * * Copyright (c) 2009 Pavel Machek <pavel@ucw.cz> * * This file is released under the GPLv2. */ #include <linux/init.h> #include <linux/rtc.h> #include "power.h" /* * We test the system suspend code by setting an RTC wakealarm a short * time in the future, then suspending. Suspending the devices won't * normally take long ... some systems only need a few milliseconds. * * The time it takes is system-specific though, so when we test this * during system bootup we allow a LOT of time. */ #define TEST_SUSPEND_SECONDS 5 static unsigned long suspend_test_start_time; void suspend_test_start(void) { /* FIXME Use better timebase than "jiffies", ideally a clocksource. * What we want is a hardware counter that will work correctly even * during the irqs-are-off stages of the suspend/resume cycle... */ suspend_test_start_time = jiffies; } void suspend_test_finish(const char *label) { long nj = jiffies - suspend_test_start_time; unsigned msec; msec = jiffies_to_msecs(abs(nj)); pr_info("PM: %s took %d.%03d seconds\n", label, msec / 1000, msec % 1000); /* Warning on suspend means the RTC alarm period needs to be * larger -- the system was sooo slooowwww to suspend that the * alarm (should have) fired before the system went to sleep! * * Warning on either suspend or resume also means the system * has some performance issues. The stack dump of a WARN_ON * is more likely to get the right attention than a printk... */ WARN(msec > (TEST_SUSPEND_SECONDS * 1000), "Component: %s\n", label); } /* * To test system suspend, we need a hands-off mechanism to resume the * system. RTCs wake alarms are a common self-contained mechanism. */ static void __init test_wakealarm(struct rtc_device *rtc, suspend_state_t state) { static char err_readtime[] __initdata = KERN_ERR "PM: can't read %s time, err %d\n"; static char err_wakealarm [] __initdata = KERN_ERR "PM: can't set %s wakealarm, err %d\n"; static char err_suspend[] __initdata = KERN_ERR "PM: suspend test failed, error %d\n"; static char info_test[] __initdata = KERN_INFO "PM: test RTC wakeup from '%s' suspend\n"; unsigned long now; struct rtc_wkalrm alm; int status; /* this may fail if the RTC hasn't been initialized */ status = rtc_read_time(rtc, &alm.time); if (status < 0) { printk(err_readtime, dev_name(&rtc->dev), status); return; } rtc_tm_to_time(&alm.time, &now); memset(&alm, 0, sizeof alm); rtc_time_to_tm(now + TEST_SUSPEND_SECONDS, &alm.time); alm.enabled = true; status = rtc_set_alarm(rtc, &alm); if (status < 0) { printk(err_wakealarm, dev_name(&rtc->dev), status); return; } if (state == PM_SUSPEND_MEM) { printk(info_test, pm_states[state]); status = pm_suspend(state); if (status == -ENODEV) state = PM_SUSPEND_STANDBY; } if (state == PM_SUSPEND_STANDBY) { printk(info_test, pm_states[state]); status = pm_suspend(state); } if (status < 0) printk(err_suspend, status); /* Some platforms can't detect that the alarm triggered the * wakeup, or (accordingly) disable it after it afterwards. * It's supposed to give oneshot behavior; cope. */ alm.enabled = false; rtc_set_alarm(rtc, &alm); } static int __init has_wakealarm(struct device *dev, void *name_ptr) { struct rtc_device *candidate = to_rtc_device(dev); if (!candidate->ops->set_alarm) return 0; if (!device_may_wakeup(candidate->dev.parent)) return 0; *(const char **)name_ptr = dev_name(dev); return 1; } /* * Kernel options like "test_suspend=mem" force suspend/resume sanity tests * at startup time. They're normally disabled, for faster boot and because * we can't know which states really work on this particular system. */ static suspend_state_t test_state __initdata = PM_SUSPEND_ON; static char warn_bad_state[] __initdata = KERN_WARNING "PM: can't test '%s' suspend state\n"; static int __init setup_test_suspend(char *value) { unsigned i; /* "=mem" ==> "mem" */ value++; for (i = 0; i < PM_SUSPEND_MAX; i++) { if (!pm_states[i]) continue; if (strcmp(pm_states[i], value) != 0) continue; test_state = (__force suspend_state_t) i; return 0; } printk(warn_bad_state, value); return 0; } __setup("test_suspend", setup_test_suspend); static int __init test_suspend(void) { static char warn_no_rtc[] __initdata = KERN_WARNING "PM: no wakealarm-capable RTC driver is ready\n"; char *pony = NULL; struct rtc_device *rtc = NULL; /* PM is initialized by now; is that state testable? */ if (test_state == PM_SUSPEND_ON) goto done; if (!valid_state(test_state)) { printk(warn_bad_state, pm_states[test_state]); goto done; } /* RTCs have initialized by now too ... can we use one? */ class_find_device(rtc_class, NULL, &pony, has_wakealarm); if (pony) rtc = rtc_class_open(pony); if (!rtc) { printk(warn_no_rtc); goto done; } /* go for it */ test_wakealarm(rtc, test_state); rtc_class_close(rtc); done: return 0; } late_initcall(test_suspend);