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>
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 1f9be53..5723446 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1195,6 +1195,41 @@
}
/**
+ * 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#.
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 5d169bc..b95b0a0 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -49,6 +49,7 @@
extern int pci_set_platform_pm(struct pci_platform_pm_ops *ops);
extern void pci_update_current_state(struct pci_dev *dev, pci_power_t state);
extern void pci_disable_enabled_device(struct pci_dev *dev);
+extern bool pci_check_pme_status(struct pci_dev *dev);
extern void pci_pm_init(struct pci_dev *dev);
extern void platform_pci_wakeup_init(struct pci_dev *dev);
extern void pci_allocate_cap_save_buffers(struct pci_dev *dev);