release/src-rt-6.x.4708/linux/linux-2.6.36/kernel/power/suspend_test.c

   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
  26 void suspend_test_start(void)
  27 {
  28         suspend_test_start_time = jiffies;
  29 }
  30
  31 void suspend_test_finish(const char *label)
  32 {
  33         long nj = jiffies - suspend_test_start_time;
  34         unsigned msec;
  35
  36         msec = jiffies_to_msecs(abs(nj));
  37         pr_info("PM: %s took %d.%03d seconds\n", label,
  38                         msec / 1000, msec % 1000);
  39
  40         /* Warning on suspend means the RTC alarm period needs to be
  41          * larger -- the system was sooo slooowwww to suspend that the
  42          * alarm (should have) fired before the system went to sleep!
  43          *
  44          * Warning on either suspend or resume also means the system
  45          * has some performance issues.  The stack dump of a WARN_ON
  46          * is more likely to get the right attention than a printk...
  47          */
  48         WARN(msec > (TEST_SUSPEND_SECONDS * 1000),
  49              "Component: %s, time: %u\n", label, msec);
  50 }
  51
  52 /*
  53  * To test system suspend, we need a hands-off mechanism to resume the
  54  * system.  RTCs wake alarms are a common self-contained mechanism.
  55  */
  56
  57 static void __init test_wakealarm(struct rtc_device *rtc, suspend_state_t state)
  58 {
  59         static char err_readtime[] __initdata =
  60                 KERN_ERR "PM: can't read %s time, err %d\n";
  61         static char err_wakealarm [] __initdata =
  62                 KERN_ERR "PM: can't set %s wakealarm, err %d\n";
  63         static char err_suspend[] __initdata =
  64                 KERN_ERR "PM: suspend test failed, error %d\n";
  65         static char info_test[] __initdata =
  66                 KERN_INFO "PM: test RTC wakeup from '%s' suspend\n";
  67
  68         unsigned long           now;
  69         struct rtc_wkalrm       alm;
  70         int                     status;
  71
  72         /* this may fail if the RTC hasn't been initialized */
  73         status = rtc_read_time(rtc, &alm.time);
  74         if (status < 0) {
  75                 printk(err_readtime, dev_name(&rtc->dev), status);
  76                 return;
  77         }
  78         rtc_tm_to_time(&alm.time, &now);
  79
  80         memset(&alm, 0, sizeof alm);
  81         rtc_time_to_tm(now + TEST_SUSPEND_SECONDS, &alm.time);
  82         alm.enabled = true;
  83
  84         status = rtc_set_alarm(rtc, &alm);
  85         if (status < 0) {
  86                 printk(err_wakealarm, dev_name(&rtc->dev), status);
  87                 return;
  88         }
  89
  90         if (state == PM_SUSPEND_MEM) {
  91                 printk(info_test, pm_states[state]);
  92                 status = pm_suspend(state);
  93                 if (status == -ENODEV)
  94                         state = PM_SUSPEND_STANDBY;
  95         }
  96         if (state == PM_SUSPEND_STANDBY) {
  97                 printk(info_test, pm_states[state]);
  98                 status = pm_suspend(state);
  99         }
 100         if (status < 0)
 101                 printk(err_suspend, status);
 102
 103         /* Some platforms can't detect that the alarm triggered the
 104          * wakeup, or (accordingly) disable it after it afterwards.
 105          * It's supposed to give oneshot behavior; cope.
 106          */
 107         alm.enabled = false;
 108         rtc_set_alarm(rtc, &alm);
 109 }
 110
 111 static int __init has_wakealarm(struct device *dev, void *name_ptr)
 112 {
 113         struct rtc_device *candidate = to_rtc_device(dev);
 114
 115         if (!candidate->ops->set_alarm)
 116                 return 0;
 117         if (!device_may_wakeup(candidate->dev.parent))
 118                 return 0;
 119
 120         *(const char **)name_ptr = dev_name(dev);
 121         return 1;
 122 }
 123
 124 /*
 125  * Kernel options like "test_suspend=mem" force suspend/resume sanity tests
 126  * at startup time.  They're normally disabled, for faster boot and because
 127  * we can't know which states really work on this particular system.
 128  */
 129 static suspend_state_t test_state __initdata = PM_SUSPEND_ON;
 130
 131 static char warn_bad_state[] __initdata =
 132         KERN_WARNING "PM: can't test '%s' suspend state\n";
 133
 134 static int __init setup_test_suspend(char *value)
 135 {
 136         unsigned i;
 137
 138         /* "=mem" ==> "mem" */
 139         value++;
 140         for (i = 0; i < PM_SUSPEND_MAX; i++) {
 141                 if (!pm_states[i])
 142                         continue;
 143                 if (strcmp(pm_states[i], value) != 0)
 144                         continue;
 145                 test_state = (__force suspend_state_t) i;
 146                 return 0;
 147         }
 148         printk(warn_bad_state, value);
 149         return 0;
 150 }
 151 __setup("test_suspend", setup_test_suspend);
 152
 153 static int __init test_suspend(void)
 154 {
 155         static char             warn_no_rtc[] __initdata =
 156                 KERN_WARNING "PM: no wakealarm-capable RTC driver is ready\n";
 157
 158         char                    *pony = NULL;
 159         struct rtc_device       *rtc = NULL;
 160
 161         /* PM is initialized by now; is that state testable? */
 162         if (test_state == PM_SUSPEND_ON)
 163                 goto done;
 164         if (!valid_state(test_state)) {
 165                 printk(warn_bad_state, pm_states[test_state]);
 166                 goto done;
 167         }
 168
 169         /* RTCs have initialized by now too ... can we use one? */
 170         class_find_device(rtc_class, NULL, &pony, has_wakealarm);
 171         if (pony)
 172                 rtc = rtc_class_open(pony);
 173         if (!rtc) {
 174                 printk(warn_no_rtc);
 175                 goto done;
 176         }
 177
 178         /* go for it */
 179         test_wakealarm(rtc, test_state);
 180         rtc_class_close(rtc);
 181 done:
 182         return 0;
 183 }
 184 late_initcall(test_suspend);