/* * 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	10 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, time: %u\n", label, msec);} /* * 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, const void *data){	struct rtc_device *candidate = to_rtc_device(dev); 	if (!candidate->ops->set_alarm)		return 0;	if (!device_may_wakeup(candidate->dev.parent))		return 0; 	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"; 	struct rtc_device	*rtc = NULL;	struct device		*dev; 	/* 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? */	dev = class_find_device(rtc_class, NULL, NULL, has_wakealarm);	if (dev)		rtc = rtc_class_open(dev_name(dev));	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);