| 1 | /* |
| 2 | * suspend.c - Functions for putting devices to sleep. |
| 3 | * |
| 4 | * Copyright (c) 2003 Patrick Mochel |
| 5 | * Copyright (c) 2003 Open Source Development Labs |
| 6 | * |
| 7 | * This file is released under the GPLv2 |
| 8 | * |
| 9 | */ |
| 10 | |
| 11 | #include <linux/device.h> |
| 12 | #include <linux/kallsyms.h> |
| 13 | #include <linux/pm.h> |
| 14 | #include "../base.h" |
| 15 | #include "power.h" |
| 16 | |
| 17 | /* |
| 18 | * The entries in the dpm_active list are in a depth first order, simply |
| 19 | * because children are guaranteed to be discovered after parents, and |
| 20 | * are inserted at the back of the list on discovery. |
| 21 | * |
| 22 | * All list on the suspend path are done in reverse order, so we operate |
| 23 | * on the leaves of the device tree (or forests, depending on how you want |
| 24 | * to look at it ;) first. As nodes are removed from the back of the list, |
| 25 | * they are inserted into the front of their destintation lists. |
| 26 | * |
| 27 | * Things are the reverse on the resume path - iterations are done in |
| 28 | * forward order, and nodes are inserted at the back of their destination |
| 29 | * lists. This way, the ancestors will be accessed before their descendents. |
| 30 | */ |
| 31 | |
| 32 | static inline char *suspend_verb(u32 event) |
| 33 | { |
| 34 | switch (event) { |
| 35 | case PM_EVENT_SUSPEND: return "suspend"; |
| 36 | case PM_EVENT_FREEZE: return "freeze"; |
| 37 | case PM_EVENT_PRETHAW: return "prethaw"; |
| 38 | default: return "(unknown suspend event)"; |
| 39 | } |
| 40 | } |
| 41 | |
| 42 | |
| 43 | static void |
| 44 | suspend_device_dbg(struct device *dev, pm_message_t state, char *info) |
| 45 | { |
| 46 | dev_dbg(dev, "%s%s%s\n", info, suspend_verb(state.event), |
| 47 | ((state.event == PM_EVENT_SUSPEND) && device_may_wakeup(dev)) ? |
| 48 | ", may wakeup" : ""); |
| 49 | } |
| 50 | |
| 51 | /** |
| 52 | * suspend_device - Save state of one device. |
| 53 | * @dev: Device. |
| 54 | * @state: Power state device is entering. |
| 55 | */ |
| 56 | |
| 57 | int suspend_device(struct device * dev, pm_message_t state) |
| 58 | { |
| 59 | int error = 0; |
| 60 | |
| 61 | down(&dev->sem); |
| 62 | if (dev->power.power_state.event) { |
| 63 | dev_dbg(dev, "PM: suspend %d-->%d\n", |
| 64 | dev->power.power_state.event, state.event); |
| 65 | } |
| 66 | |
| 67 | if (dev->class && dev->class->suspend) { |
| 68 | suspend_device_dbg(dev, state, "class "); |
| 69 | error = dev->class->suspend(dev, state); |
| 70 | suspend_report_result(dev->class->suspend, error); |
| 71 | } |
| 72 | |
| 73 | if (!error && dev->type && dev->type->suspend) { |
| 74 | suspend_device_dbg(dev, state, "type "); |
| 75 | error = dev->type->suspend(dev, state); |
| 76 | suspend_report_result(dev->type->suspend, error); |
| 77 | } |
| 78 | |
| 79 | if (!error && dev->bus && dev->bus->suspend) { |
| 80 | suspend_device_dbg(dev, state, ""); |
| 81 | error = dev->bus->suspend(dev, state); |
| 82 | suspend_report_result(dev->bus->suspend, error); |
| 83 | } |
| 84 | up(&dev->sem); |
| 85 | return error; |
| 86 | } |
| 87 | |
| 88 | |
| 89 | /* |
| 90 | * This is called with interrupts off, only a single CPU |
| 91 | * running. We can't acquire a mutex or semaphore (and we don't |
| 92 | * need the protection) |
| 93 | */ |
| 94 | static int suspend_device_late(struct device *dev, pm_message_t state) |
| 95 | { |
| 96 | int error = 0; |
| 97 | |
| 98 | if (dev->bus && dev->bus->suspend_late) { |
| 99 | suspend_device_dbg(dev, state, "LATE "); |
| 100 | error = dev->bus->suspend_late(dev, state); |
| 101 | suspend_report_result(dev->bus->suspend_late, error); |
| 102 | } |
| 103 | return error; |
| 104 | } |
| 105 | |
| 106 | /** |
| 107 | * device_suspend - Save state and stop all devices in system. |
| 108 | * @state: Power state to put each device in. |
| 109 | * |
| 110 | * Walk the dpm_active list, call ->suspend() for each device, and move |
| 111 | * it to the dpm_off list. |
| 112 | * |
| 113 | * (For historical reasons, if it returns -EAGAIN, that used to mean |
| 114 | * that the device would be called again with interrupts disabled. |
| 115 | * These days, we use the "suspend_late()" callback for that, so we |
| 116 | * print a warning and consider it an error). |
| 117 | * |
| 118 | * If we get a different error, try and back out. |
| 119 | * |
| 120 | * If we hit a failure with any of the devices, call device_resume() |
| 121 | * above to bring the suspended devices back to life. |
| 122 | * |
| 123 | */ |
| 124 | |
| 125 | int device_suspend(pm_message_t state) |
| 126 | { |
| 127 | int error = 0; |
| 128 | |
| 129 | might_sleep(); |
| 130 | mutex_lock(&dpm_mtx); |
| 131 | mutex_lock(&dpm_list_mtx); |
| 132 | while (!list_empty(&dpm_active) && error == 0) { |
| 133 | struct list_head * entry = dpm_active.prev; |
| 134 | struct device * dev = to_device(entry); |
| 135 | |
| 136 | get_device(dev); |
| 137 | mutex_unlock(&dpm_list_mtx); |
| 138 | |
| 139 | error = suspend_device(dev, state); |
| 140 | |
| 141 | mutex_lock(&dpm_list_mtx); |
| 142 | |
| 143 | /* Check if the device got removed */ |
| 144 | if (!list_empty(&dev->power.entry)) { |
| 145 | /* Move it to the dpm_off list */ |
| 146 | if (!error) |
| 147 | list_move(&dev->power.entry, &dpm_off); |
| 148 | } |
| 149 | if (error) |
| 150 | printk(KERN_ERR "Could not suspend device %s: " |
| 151 | "error %d%s\n", |
| 152 | kobject_name(&dev->kobj), error, |
| 153 | error == -EAGAIN ? " (please convert to suspend_late)" : ""); |
| 154 | put_device(dev); |
| 155 | } |
| 156 | mutex_unlock(&dpm_list_mtx); |
| 157 | if (error) |
| 158 | dpm_resume(); |
| 159 | |
| 160 | mutex_unlock(&dpm_mtx); |
| 161 | return error; |
| 162 | } |
| 163 | |
| 164 | EXPORT_SYMBOL_GPL(device_suspend); |
| 165 | |
| 166 | /** |
| 167 | * device_power_down - Shut down special devices. |
| 168 | * @state: Power state to enter. |
| 169 | * |
| 170 | * Walk the dpm_off_irq list, calling ->power_down() for each device that |
| 171 | * couldn't power down the device with interrupts enabled. When we're |
| 172 | * done, power down system devices. |
| 173 | */ |
| 174 | |
| 175 | int device_power_down(pm_message_t state) |
| 176 | { |
| 177 | int error = 0; |
| 178 | struct device * dev; |
| 179 | |
| 180 | while (!list_empty(&dpm_off)) { |
| 181 | struct list_head * entry = dpm_off.prev; |
| 182 | |
| 183 | dev = to_device(entry); |
| 184 | error = suspend_device_late(dev, state); |
| 185 | if (error) |
| 186 | goto Error; |
| 187 | list_move(&dev->power.entry, &dpm_off_irq); |
| 188 | } |
| 189 | |
| 190 | error = sysdev_suspend(state); |
| 191 | Done: |
| 192 | return error; |
| 193 | Error: |
| 194 | printk(KERN_ERR "Could not power down device %s: " |
| 195 | "error %d\n", kobject_name(&dev->kobj), error); |
| 196 | dpm_power_up(); |
| 197 | goto Done; |
| 198 | } |
| 199 | |
| 200 | EXPORT_SYMBOL_GPL(device_power_down); |
| 201 | |
| 202 | void __suspend_report_result(const char *function, void *fn, int ret) |
| 203 | { |
| 204 | if (ret) { |
| 205 | printk(KERN_ERR "%s(): ", function); |
| 206 | print_fn_descriptor_symbol("%s() returns ", (unsigned long)fn); |
| 207 | printk("%d\n", ret); |
| 208 | } |
| 209 | } |
| 210 | EXPORT_SYMBOL_GPL(__suspend_report_result); |