PM: Separate suspend to RAM functionality from core
Move the suspend to RAM and standby code from kernel/power/main.c
to two separate files, kernel/power/suspend.c containing the basic
functions and kernel/power/suspend_test.c containing the automatic
suspend test facility based on the RTC clock alarm.
There are no changes in functionality related to these modifications.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
diff --git a/kernel/power/suspend_test.c b/kernel/power/suspend_test.c
new file mode 100644
index 0000000..17d8bb1a
--- /dev/null
+++ b/kernel/power/suspend_test.c
@@ -0,0 +1,187 @@
+/*
+ * 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);