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Commit 404cc2d8 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki Committed by Jesse Barnes
Browse files

PCI PM: Introduce pci_prepare_to_sleep and pci_back_from_sleep 



Introduce functions pci_prepare_to_sleep() and pci_back_from_sleep(),
to be used by the PCI drivers that want to place their devices into
the lowest power state appropiate for them (PCI_D3hot, if the device
is not supposed to wake up the system, or the deepest state from
which the wake-up is possible, otherwise) while the system is being
prepared to go into a sleeping state and to put them back into D0
during the subsequent transition to the working state.

Signed-off-by: default avatarRafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
parent eb9d0fe4

drivers/pci/pci.c

+83 −0
Original line number Original line Diff line number Diff line
@@ -1146,6 +1146,87 @@ int pci_enable_wake(struct pci_dev *dev, pci_power_t state, int enable) 
	return pme_done ? 0 : error;

	return pme_done ? 0 : error;

}

}





/**

 * pci_prepare_to_sleep - prepare PCI device for system-wide transition into

 *                        a sleep state

 * @dev: Device to handle.

 *

 * Choose the power state appropriate for the device depending on whether

 * it can wake up the system and/or is power manageable by the platform

 * (PCI_D3hot is the default) and put the device into that state.

 */

int pci_prepare_to_sleep(struct pci_dev *dev)

{

	pci_power_t target_state = PCI_D3hot;

	int pm = pci_find_capability(dev, PCI_CAP_ID_PM);

	int error;



	if (platform_pci_power_manageable(dev)) {

		/*

		 * Call the platform to choose the target state of the device

		 * and enable wake-up from this state if supported.

		 */

		pci_power_t state = platform_pci_choose_state(dev);



		switch (state) {

		case PCI_POWER_ERROR:

		case PCI_UNKNOWN:

			break;

		case PCI_D1:

		case PCI_D2:

			if (pci_no_d1d2(dev))

				break;

		default:

			target_state = state;

			pci_enable_wake(dev, target_state, true);

		}

	} else if (device_may_wakeup(&dev->dev)) {

		/*

		 * Find the deepest state from which the device can generate

		 * wake-up events, make it the target state and enable device

		 * to generate PME#.

		 */

		u16 pmc;



		if (!pm)

			return -EIO;



		pci_read_config_word(dev, pm + PCI_PM_PMC, &pmc);

		if (pmc & PCI_PM_CAP_PME_MASK) {

			if (!(pmc & PCI_PM_CAP_PME_D3)) {

				/* Device cannot generate PME# from D3_hot */

				if (pmc & PCI_PM_CAP_PME_D2)

					target_state = PCI_D2;

				else if (pmc & PCI_PM_CAP_PME_D1)

					target_state = PCI_D1;

				else

					target_state = PCI_D0;

			}

			pci_pme_active(dev, pm, true);

		}

	}



	error = pci_set_power_state(dev, target_state);



	if (error)

		pci_enable_wake(dev, target_state, false);



	return error;

}



/**

 * pci_back_from_sleep - turn PCI device on during system-wide transition into

 *                       the working state a sleep state

 * @dev: Device to handle.

 *

 * Disable device's sytem wake-up capability and put it into D0.

 */

int pci_back_from_sleep(struct pci_dev *dev)

{

	pci_enable_wake(dev, PCI_D0, false);

	return pci_set_power_state(dev, PCI_D0);

}



/**

/**

 * pci_pm_init - Initialize PM functions of given PCI device

 * pci_pm_init - Initialize PM functions of given PCI device

 * @dev: PCI device to handle.

 * @dev: PCI device to handle.
@@ -1853,5 +1934,7 @@ EXPORT_SYMBOL(pci_set_power_state); 
EXPORT_SYMBOL(pci_save_state);

EXPORT_SYMBOL(pci_save_state);

EXPORT_SYMBOL(pci_restore_state);

EXPORT_SYMBOL(pci_restore_state);

EXPORT_SYMBOL(pci_enable_wake);

EXPORT_SYMBOL(pci_enable_wake);

EXPORT_SYMBOL(pci_prepare_to_sleep);

EXPORT_SYMBOL(pci_back_from_sleep);

EXPORT_SYMBOL_GPL(pci_set_pcie_reset_state);

EXPORT_SYMBOL_GPL(pci_set_pcie_reset_state);

include/linux/pci.h

+2 −0
Original line number Original line Diff line number Diff line
@@ -632,6 +632,8 @@ int pci_restore_state(struct pci_dev *dev); 
int pci_set_power_state(struct pci_dev *dev, pci_power_t state);

int pci_set_power_state(struct pci_dev *dev, pci_power_t state);

pci_power_t pci_choose_state(struct pci_dev *dev, pm_message_t state);

pci_power_t pci_choose_state(struct pci_dev *dev, pm_message_t state);

int pci_enable_wake(struct pci_dev *dev, pci_power_t state, int enable);

int pci_enable_wake(struct pci_dev *dev, pci_power_t state, int enable);

int pci_prepare_to_sleep(struct pci_dev *dev);

int pci_back_from_sleep(struct pci_dev *dev);





/* Functions for PCI Hotplug drivers to use */

/* Functions for PCI Hotplug drivers to use */

int pci_bus_find_capability(struct pci_bus *bus, unsigned int devfn, int cap);

int pci_bus_find_capability(struct pci_bus *bus, unsigned int devfn, int cap);