diff options
Diffstat (limited to 'kernel/power/suspend_test.c')
| -rw-r--r-- | kernel/power/suspend_test.c | 219 |
1 files changed, 219 insertions, 0 deletions
diff --git a/kernel/power/suspend_test.c b/kernel/power/suspend_test.c new file mode 100644 index 000000000..b663a97f5 --- /dev/null +++ b/kernel/power/suspend_test.c @@ -0,0 +1,219 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * kernel/power/suspend_test.c - Suspend to RAM and standby test facility. + * + * Copyright (c) 2009 Pavel Machek <pavel@ucw.cz> + */ + +#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; +static u32 test_repeat_count_max = 1; +static u32 test_repeat_count_current; + +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"; + + time64_t now; + struct rtc_wkalrm alm; + int status; + + /* this may fail if the RTC hasn't been initialized */ +repeat: + status = rtc_read_time(rtc, &alm.time); + if (status < 0) { + printk(err_readtime, dev_name(&rtc->dev), status); + return; + } + now = rtc_tm_to_time64(&alm.time); + + memset(&alm, 0, sizeof alm); + rtc_time64_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) + state = PM_SUSPEND_TO_IDLE; + } + if (state == PM_SUSPEND_TO_IDLE) { + printk(info_test, pm_states[state]); + status = pm_suspend(state); + } + + if (status < 0) + printk(err_suspend, status); + + test_repeat_count_current++; + if (test_repeat_count_current < test_repeat_count_max) + goto repeat; + + /* 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 (!test_bit(RTC_FEATURE_ALARM, candidate->features)) + 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 const char *test_state_label __initdata; + +static char warn_bad_state[] __initdata = + KERN_WARNING "PM: can't test '%s' suspend state\n"; + +static int __init setup_test_suspend(char *value) +{ + int i; + char *repeat; + char *suspend_type; + + /* example : "=mem[,N]" ==> "mem[,N]" */ + value++; + suspend_type = strsep(&value, ","); + if (!suspend_type) + return 1; + + repeat = strsep(&value, ","); + if (repeat) { + if (kstrtou32(repeat, 0, &test_repeat_count_max)) + return 1; + } + + for (i = PM_SUSPEND_MIN; i < PM_SUSPEND_MAX; i++) + if (!strcmp(pm_labels[i], suspend_type)) { + test_state_label = pm_labels[i]; + return 1; + } + + printk(warn_bad_state, suspend_type); + return 1; +} +__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; + suspend_state_t test_state; + + /* PM is initialized by now; is that state testable? */ + if (!test_state_label) + return 0; + + for (test_state = PM_SUSPEND_MIN; test_state < PM_SUSPEND_MAX; test_state++) { + const char *state_label = pm_states[test_state]; + + if (state_label && !strcmp(test_state_label, state_label)) + break; + } + if (test_state == PM_SUSPEND_MAX) { + printk(warn_bad_state, test_state_label); + return 0; + } + + /* 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)); + put_device(dev); + } + if (!rtc) { + printk(warn_no_rtc); + return 0; + } + + /* go for it */ + test_wakealarm(rtc, test_state); + rtc_class_close(rtc); + return 0; +} +late_initcall(test_suspend); |