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authorRafael J. Wysocki <rjw@sisk.pl>2008-07-07 03:35:26 +0200
committerJesse Barnes <jbarnes@virtuousgeek.org>2008-07-07 16:26:33 -0700
commit404cc2d8ce41ed4031958fba8e633767e8a2e028 (patch)
treed679e1ea92d6ae8e72309c02197fd5f1480651fb /drivers/pci
parenteb9d0fe40e313c0a74115ef456a2e43a6c8da72f (diff)
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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: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Diffstat (limited to 'drivers/pci')
-rw-r--r--drivers/pci/pci.c83
1 files changed, 83 insertions, 0 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index a6b1b6f96abc..1b0ec45e9934 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1147,6 +1147,87 @@ int pci_enable_wake(struct pci_dev *dev, pci_power_t state, int enable)
}
/**
+ * 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);