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    Subject[PATCH 1/8] PCI PM: Add function for checking PME status of devices
    Date
    From: Rafael J. Wysocki <rjw@sisk.pl>

    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>
    ---
    drivers/pci/pci.c | 35 +++++++++++++++++++++++++++++++++++
    drivers/pci/pci.h | 1 +
    2 files changed, 36 insertions(+)

    Index: linux-2.6/drivers/pci/pci.h
    ===================================================================
    --- linux-2.6.orig/drivers/pci/pci.h
    +++ linux-2.6/drivers/pci/pci.h
    @@ -49,6 +49,7 @@ struct pci_platform_pm_ops {
    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);
    Index: linux-2.6/drivers/pci/pci.c
    ===================================================================
    --- linux-2.6.orig/drivers/pci/pci.c
    +++ linux-2.6/drivers/pci/pci.c
    @@ -1195,6 +1195,41 @@ int pci_set_pcie_reset_state(struct pci_
    }

    /**
    + * 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#.


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