af70316af1
This adds a per-device semaphore that is taken before every call from the core to a driver method. This prevents e.g. simultaneous calls to the ->suspend() or ->resume() and ->probe() or ->release(), potentially saving a whole lot of headaches. It also moves us a step closer to removing the bus rwsem, since it protects the fields in struct device that are modified by the core. Signed-off-by: Patrick Mochel <mochel@digitalimplant.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
126 lines
2.4 KiB
C
126 lines
2.4 KiB
C
/*
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* resume.c - Functions for waking devices up.
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*
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* Copyright (c) 2003 Patrick Mochel
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* Copyright (c) 2003 Open Source Development Labs
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*
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* This file is released under the GPLv2
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*
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*/
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#include <linux/device.h>
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#include "power.h"
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extern int sysdev_resume(void);
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/**
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* resume_device - Restore state for one device.
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* @dev: Device.
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*
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*/
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int resume_device(struct device * dev)
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{
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int error = 0;
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down(&dev->sem);
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if (dev->power.pm_parent
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&& dev->power.pm_parent->power.power_state) {
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dev_err(dev, "PM: resume from %d, parent %s still %d\n",
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dev->power.power_state,
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dev->power.pm_parent->bus_id,
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dev->power.pm_parent->power.power_state);
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}
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if (dev->bus && dev->bus->resume) {
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dev_dbg(dev,"resuming\n");
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error = dev->bus->resume(dev);
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}
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up(&dev->sem);
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return error;
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}
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void dpm_resume(void)
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{
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down(&dpm_list_sem);
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while(!list_empty(&dpm_off)) {
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struct list_head * entry = dpm_off.next;
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struct device * dev = to_device(entry);
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get_device(dev);
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list_del_init(entry);
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list_add_tail(entry, &dpm_active);
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up(&dpm_list_sem);
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if (!dev->power.prev_state)
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resume_device(dev);
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down(&dpm_list_sem);
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put_device(dev);
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}
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up(&dpm_list_sem);
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}
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/**
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* device_resume - Restore state of each device in system.
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*
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* Walk the dpm_off list, remove each entry, resume the device,
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* then add it to the dpm_active list.
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*/
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void device_resume(void)
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{
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down(&dpm_sem);
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dpm_resume();
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up(&dpm_sem);
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}
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EXPORT_SYMBOL_GPL(device_resume);
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/**
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* device_power_up_irq - Power on some devices.
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*
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* Walk the dpm_off_irq list and power each device up. This
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* is used for devices that required they be powered down with
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* interrupts disabled. As devices are powered on, they are moved to
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* the dpm_suspended list.
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*
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* Interrupts must be disabled when calling this.
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*/
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void dpm_power_up(void)
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{
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while(!list_empty(&dpm_off_irq)) {
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struct list_head * entry = dpm_off_irq.next;
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struct device * dev = to_device(entry);
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get_device(dev);
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list_del_init(entry);
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list_add_tail(entry, &dpm_active);
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resume_device(dev);
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put_device(dev);
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}
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}
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/**
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* device_pm_power_up - Turn on all devices that need special attention.
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*
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* Power on system devices then devices that required we shut them down
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* with interrupts disabled.
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* Called with interrupts disabled.
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*/
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void device_power_up(void)
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{
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sysdev_resume();
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dpm_power_up();
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}
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EXPORT_SYMBOL_GPL(device_power_up);
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