summaryrefslogtreecommitdiffstats
path: root/kernel/power/main.c
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/power/main.c')
-rw-r--r--kernel/power/main.c269
1 files changed, 269 insertions, 0 deletions
diff --git a/kernel/power/main.c b/kernel/power/main.c
new file mode 100644
index 0000000..7960ddf
--- /dev/null
+++ b/kernel/power/main.c
@@ -0,0 +1,269 @@
+/*
+ * kernel/power/main.c - PM subsystem core functionality.
+ *
+ * Copyright (c) 2003 Patrick Mochel
+ * Copyright (c) 2003 Open Source Development Lab
+ *
+ * This file is released under the GPLv2
+ *
+ */
+
+#include <linux/suspend.h>
+#include <linux/kobject.h>
+#include <linux/string.h>
+#include <linux/delay.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/pm.h>
+
+
+#include "power.h"
+
+DECLARE_MUTEX(pm_sem);
+
+struct pm_ops * pm_ops = NULL;
+suspend_disk_method_t pm_disk_mode = PM_DISK_SHUTDOWN;
+
+/**
+ * pm_set_ops - Set the global power method table.
+ * @ops: Pointer to ops structure.
+ */
+
+void pm_set_ops(struct pm_ops * ops)
+{
+ down(&pm_sem);
+ pm_ops = ops;
+ up(&pm_sem);
+}
+
+
+/**
+ * suspend_prepare - Do prep work before entering low-power state.
+ * @state: State we're entering.
+ *
+ * This is common code that is called for each state that we're
+ * entering. Allocate a console, stop all processes, then make sure
+ * the platform can enter the requested state.
+ */
+
+static int suspend_prepare(suspend_state_t state)
+{
+ int error = 0;
+
+ if (!pm_ops || !pm_ops->enter)
+ return -EPERM;
+
+ pm_prepare_console();
+
+ if (freeze_processes()) {
+ error = -EAGAIN;
+ goto Thaw;
+ }
+
+ if (pm_ops->prepare) {
+ if ((error = pm_ops->prepare(state)))
+ goto Thaw;
+ }
+
+ if ((error = device_suspend(PMSG_SUSPEND))) {
+ printk(KERN_ERR "Some devices failed to suspend\n");
+ goto Finish;
+ }
+ return 0;
+ Finish:
+ if (pm_ops->finish)
+ pm_ops->finish(state);
+ Thaw:
+ thaw_processes();
+ pm_restore_console();
+ return error;
+}
+
+
+static int suspend_enter(suspend_state_t state)
+{
+ int error = 0;
+ unsigned long flags;
+
+ local_irq_save(flags);
+
+ if ((error = device_power_down(PMSG_SUSPEND))) {
+ printk(KERN_ERR "Some devices failed to power down\n");
+ goto Done;
+ }
+ error = pm_ops->enter(state);
+ device_power_up();
+ Done:
+ local_irq_restore(flags);
+ return error;
+}
+
+
+/**
+ * suspend_finish - Do final work before exiting suspend sequence.
+ * @state: State we're coming out of.
+ *
+ * Call platform code to clean up, restart processes, and free the
+ * console that we've allocated. This is not called for suspend-to-disk.
+ */
+
+static void suspend_finish(suspend_state_t state)
+{
+ device_resume();
+ if (pm_ops && pm_ops->finish)
+ pm_ops->finish(state);
+ thaw_processes();
+ pm_restore_console();
+}
+
+
+
+
+static char * pm_states[] = {
+ [PM_SUSPEND_STANDBY] = "standby",
+ [PM_SUSPEND_MEM] = "mem",
+ [PM_SUSPEND_DISK] = "disk",
+ NULL,
+};
+
+
+/**
+ * enter_state - Do common work of entering low-power state.
+ * @state: pm_state structure for state we're entering.
+ *
+ * Make sure we're the only ones trying to enter a sleep state. Fail
+ * if someone has beat us to it, since we don't want anything weird to
+ * happen when we wake up.
+ * Then, do the setup for suspend, enter the state, and cleaup (after
+ * we've woken up).
+ */
+
+static int enter_state(suspend_state_t state)
+{
+ int error;
+
+ if (down_trylock(&pm_sem))
+ return -EBUSY;
+
+ if (state == PM_SUSPEND_DISK) {
+ error = pm_suspend_disk();
+ goto Unlock;
+ }
+
+ /* Suspend is hard to get right on SMP. */
+ if (num_online_cpus() != 1) {
+ error = -EPERM;
+ goto Unlock;
+ }
+
+ pr_debug("PM: Preparing system for suspend\n");
+ if ((error = suspend_prepare(state)))
+ goto Unlock;
+
+ pr_debug("PM: Entering state.\n");
+ error = suspend_enter(state);
+
+ pr_debug("PM: Finishing up.\n");
+ suspend_finish(state);
+ Unlock:
+ up(&pm_sem);
+ return error;
+}
+
+/*
+ * This is main interface to the outside world. It needs to be
+ * called from process context.
+ */
+int software_suspend(void)
+{
+ return enter_state(PM_SUSPEND_DISK);
+}
+
+
+/**
+ * pm_suspend - Externally visible function for suspending system.
+ * @state: Enumarted value of state to enter.
+ *
+ * Determine whether or not value is within range, get state
+ * structure, and enter (above).
+ */
+
+int pm_suspend(suspend_state_t state)
+{
+ if (state > PM_SUSPEND_ON && state < PM_SUSPEND_MAX)
+ return enter_state(state);
+ return -EINVAL;
+}
+
+
+
+decl_subsys(power,NULL,NULL);
+
+
+/**
+ * state - control system power state.
+ *
+ * show() returns what states are supported, which is hard-coded to
+ * 'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
+ * 'disk' (Suspend-to-Disk).
+ *
+ * store() accepts one of those strings, translates it into the
+ * proper enumerated value, and initiates a suspend transition.
+ */
+
+static ssize_t state_show(struct subsystem * subsys, char * buf)
+{
+ int i;
+ char * s = buf;
+
+ for (i = 0; i < PM_SUSPEND_MAX; i++) {
+ if (pm_states[i])
+ s += sprintf(s,"%s ",pm_states[i]);
+ }
+ s += sprintf(s,"\n");
+ return (s - buf);
+}
+
+static ssize_t state_store(struct subsystem * subsys, const char * buf, size_t n)
+{
+ suspend_state_t state = PM_SUSPEND_STANDBY;
+ char ** s;
+ char *p;
+ int error;
+ int len;
+
+ p = memchr(buf, '\n', n);
+ len = p ? p - buf : n;
+
+ for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
+ if (*s && !strncmp(buf, *s, len))
+ break;
+ }
+ if (*s)
+ error = enter_state(state);
+ else
+ error = -EINVAL;
+ return error ? error : n;
+}
+
+power_attr(state);
+
+static struct attribute * g[] = {
+ &state_attr.attr,
+ NULL,
+};
+
+static struct attribute_group attr_group = {
+ .attrs = g,
+};
+
+
+static int __init pm_init(void)
+{
+ int error = subsystem_register(&power_subsys);
+ if (!error)
+ error = sysfs_create_group(&power_subsys.kset.kobj,&attr_group);
+ return error;
+}
+
+core_initcall(pm_init);
OpenPOWER on IntegriCloud