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authorRafael J. Wysocki <rjw@sisk.pl>2010-02-17 23:36:58 +0100
committerJesse Barnes <jbarnes@virtuousgeek.org>2010-02-22 16:20:24 -0800
commit58ff463396ad00828e922d50998787e97fd32512 (patch)
tree4964b07518a02736a23839d89bb7ac4a065dede8 /drivers/pci/pci.c
parent6d3be84aab461815978d970aa45f5bc9e52dd772 (diff)
PCI PM: Add function for checking PME status of devices
Add function pci_check_pme_status() that will check the PME status bit of given device and clear it along with the PME enable bit. It will be necessary for PCI run-time power management. Based on a patch from Shaohua Li <shaohua.li@intel.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Diffstat (limited to 'drivers/pci/pci.c')
-rw-r--r--drivers/pci/pci.c35
1 files changed, 35 insertions, 0 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 1f9be53c39b..5723446544f 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1195,6 +1195,41 @@ int pci_set_pcie_reset_state(struct pci_dev *dev, enum pcie_reset_state state)
}
/**
+ * pci_check_pme_status - Check if given device has generated PME.
+ * @dev: Device to check.
+ *
+ * Check the PME status of the device and if set, clear it and clear PME enable
+ * (if set). Return 'true' if PME status and PME enable were both set or
+ * 'false' otherwise.
+ */
+bool pci_check_pme_status(struct pci_dev *dev)
+{
+ int pmcsr_pos;
+ u16 pmcsr;
+ bool ret = false;
+
+ if (!dev->pm_cap)
+ return false;
+
+ pmcsr_pos = dev->pm_cap + PCI_PM_CTRL;
+ pci_read_config_word(dev, pmcsr_pos, &pmcsr);
+ if (!(pmcsr & PCI_PM_CTRL_PME_STATUS))
+ return false;
+
+ /* Clear PME status. */
+ pmcsr |= PCI_PM_CTRL_PME_STATUS;
+ if (pmcsr & PCI_PM_CTRL_PME_ENABLE) {
+ /* Disable PME to avoid interrupt flood. */
+ pmcsr &= ~PCI_PM_CTRL_PME_ENABLE;
+ ret = true;
+ }
+
+ pci_write_config_word(dev, pmcsr_pos, pmcsr);
+
+ return ret;
+}
+
+/**
* pci_pme_capable - check the capability of PCI device to generate PME#
* @dev: PCI device to handle.
* @state: PCI state from which device will issue PME#.