1 files changed, 144 insertions, 0 deletions

diff --git a/drivers/base/power/suspend.c b/drivers/base/power/suspend.c
new file mode 100644
index 000000000000..a0b5cf689e63
--- /dev/null
+++ b/drivers/base/power/suspend.c
@@ -0,0 +1,144 @@
+/*
+ * suspend.c - Functions for putting devices to sleep.
+ *
+ * Copyright (c) 2003 Patrick Mochel
+ * Copyright (c) 2003 Open Source Development Labs
+ *
+ * This file is released under the GPLv2
+ *
+ */
+
+#include <linux/device.h>
+#include "power.h"
+
+extern int sysdev_suspend(pm_message_t state);
+
+/*
+ * The entries in the dpm_active list are in a depth first order, simply
+ * because children are guaranteed to be discovered after parents, and
+ * are inserted at the back of the list on discovery.
+ *
+ * All list on the suspend path are done in reverse order, so we operate
+ * on the leaves of the device tree (or forests, depending on how you want
+ * to look at it ;) first. As nodes are removed from the back of the list,
+ * they are inserted into the front of their destintation lists.
+ *
+ * Things are the reverse on the resume path - iterations are done in
+ * forward order, and nodes are inserted at the back of their destination
+ * lists. This way, the ancestors will be accessed before their descendents.
+ */
+
+
+/**
+ *      suspend_device - Save state of one device.
+ *      @dev:   Device.
+ *      @state: Power state device is entering.
+ */
+
+int suspend_device(struct device * dev, pm_message_t state)
+{
+        int error = 0;
+
+        dev_dbg(dev, "suspending\n");
+
+        dev->power.prev_state = dev->power.power_state;
+
+        if (dev->bus && dev->bus->suspend && !dev->power.power_state)
+                error = dev->bus->suspend(dev, state);
+
+        return error;
+}
+
+
+/**
+ *      device_suspend - Save state and stop all devices in system.
+ *      @state:         Power state to put each device in.
+ *
+ *      Walk the dpm_active list, call ->suspend() for each device, and move
+ *      it to dpm_off.
+ *      Check the return value for each. If it returns 0, then we move the
+ *      the device to the dpm_off list. If it returns -EAGAIN, we move it to
+ *      the dpm_off_irq list. If we get a different error, try and back out.
+ *
+ *      If we hit a failure with any of the devices, call device_resume()
+ *      above to bring the suspended devices back to life.
+ *
+ */
+
+int device_suspend(pm_message_t state)
+{
+        int error = 0;
+
+        down(&dpm_sem);
+        down(&dpm_list_sem);
+        while (!list_empty(&dpm_active) && error == 0) {
+                struct list_head * entry = dpm_active.prev;
+                struct device * dev = to_device(entry);
+
+                get_device(dev);
+                up(&dpm_list_sem);
+
+                error = suspend_device(dev, state);
+
+                down(&dpm_list_sem);
+
+                /* Check if the device got removed */
+                if (!list_empty(&dev->power.entry)) {
+                        /* Move it to the dpm_off or dpm_off_irq list */
+                        if (!error) {
+                                list_del(&dev->power.entry);
+                                list_add(&dev->power.entry, &dpm_off);
+                        } else if (error == -EAGAIN) {
+                                list_del(&dev->power.entry);
+                                list_add(&dev->power.entry, &dpm_off_irq);
+                                error = 0;
+                        }
+                }
+                if (error)
+                        printk(KERN_ERR "Could not suspend device %s: "
+                                "error %d\n", kobject_name(&dev->kobj), error);
+                put_device(dev);
+        }
+        up(&dpm_list_sem);
+        if (error)
+                dpm_resume();
+        up(&dpm_sem);
+        return error;
+}
+
+EXPORT_SYMBOL_GPL(device_suspend);
+
+
+/**
+ *      device_power_down - Shut down special devices.
+ *      @state:         Power state to enter.
+ *
+ *      Walk the dpm_off_irq list, calling ->power_down() for each device that
+ *      couldn't power down the device with interrupts enabled. When we're
+ *      done, power down system devices.
+ */
+
+int device_power_down(pm_message_t state)
+{
+        int error = 0;
+        struct device * dev;
+
+        list_for_each_entry_reverse(dev, &dpm_off_irq, power.entry) {
+                if ((error = suspend_device(dev, state)))
+                        break;
+        }
+        if (error)
+                goto Error;
+        if ((error = sysdev_suspend(state)))
+                goto Error;
+ Done:
+        return error;
+ Error:
+        printk(KERN_ERR "Could not power down device %s: "
+                "error %d\n", kobject_name(&dev->kobj), error);
+        dpm_power_up();
+        goto Done;
+}
+
+EXPORT_SYMBOL_GPL(device_power_down);
+