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PCI PM: Introduce pci_prepare_to_sleep and pci_back_from_sleep

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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: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
This commit is contained in:
Rafael J. Wysocki 2008-07-07 03:35:26 +02:00 committed by Jesse Barnes
parent eb9d0fe40e
commit 404cc2d8ce
2 changed files with 85 additions and 0 deletions
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83
drivers/pci/pci.c
View file

@ -1146,6 +1146,87 @@ int pci_enable_wake(struct pci_dev *dev, pci_power_t state, int enable)
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
* @dev: PCI device to handle.
@ -1853,5 +1934,7 @@ EXPORT_SYMBOL(pci_set_power_state);
EXPORT_SYMBOL(pci_save_state);
EXPORT_SYMBOL(pci_restore_state);
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);

2
include/linux/pci.h
View file

@ -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);
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_prepare_to_sleep(struct pci_dev *dev);
int pci_back_from_sleep(struct pci_dev *dev);
/* Functions for PCI Hotplug drivers to use */
int pci_bus_find_capability(struct pci_bus *bus, unsigned int devfn, int cap);