/*
   * File:	pci-acpi.c

   * Purpose:	Provide PCI support in ACPI

   *

   * Copyright (C) 2005 David Shaohua Li <shaohua.li@intel.com>
   * Copyright (C) 2004 Tom Long Nguyen <tom.l.nguyen@intel.com>
   * Copyright (C) 2004 Intel Corp.

   */
  
  #include <linux/delay.h>
  #include <linux/init.h>
  #include <linux/pci.h>
  #include <linux/module.h>

  #include <linux/pci-aspm.h>

  #include <acpi/acpi.h>

  #include <acpi/acpi_bus.h>
  
  #include <linux/pci-acpi.h>

  #include <linux/pm_runtime.h>

  #include "pci.h"

  static DEFINE_MUTEX(pci_acpi_pm_notify_mtx);
  
  /**
   * pci_acpi_wake_bus - Wake-up notification handler for root buses.
   * @handle: ACPI handle of a device the notification is for.
   * @event: Type of the signaled event.
   * @context: PCI root bus to wake up devices on.
   */
  static void pci_acpi_wake_bus(acpi_handle handle, u32 event, void *context)
  {
  	struct pci_bus *pci_bus = context;
  
  	if (event == ACPI_NOTIFY_DEVICE_WAKE && pci_bus)
  		pci_pme_wakeup_bus(pci_bus);
  }
  
  /**
   * pci_acpi_wake_dev - Wake-up notification handler for PCI devices.
   * @handle: ACPI handle of a device the notification is for.
   * @event: Type of the signaled event.
   * @context: PCI device object to wake up.
   */
  static void pci_acpi_wake_dev(acpi_handle handle, u32 event, void *context)
  {
  	struct pci_dev *pci_dev = context;

  	if (event != ACPI_NOTIFY_DEVICE_WAKE || !pci_dev)
  		return;
  
  	if (!pci_dev->pm_cap || !pci_dev->pme_support
  	     || pci_check_pme_status(pci_dev)) {

  		if (pci_dev->pme_poll)
  			pci_dev->pme_poll = false;

  		pci_wakeup_event(pci_dev);

  		pm_runtime_resume(&pci_dev->dev);

  	}

  
  	if (pci_dev->subordinate)
  		pci_pme_wakeup_bus(pci_dev->subordinate);

  }
  
  /**
   * add_pm_notifier - Register PM notifier for given ACPI device.
   * @dev: ACPI device to add the notifier for.
   * @context: PCI device or bus to check for PME status if an event is signaled.
   *
   * NOTE: @dev need not be a run-wake or wake-up device to be a valid source of
   * PM wake-up events.  For example, wake-up events may be generated for bridges
   * if one of the devices below the bridge is signaling PME, even if the bridge
   * itself doesn't have a wake-up GPE associated with it.
   */
  static acpi_status add_pm_notifier(struct acpi_device *dev,
  				   acpi_notify_handler handler,
  				   void *context)
  {
  	acpi_status status = AE_ALREADY_EXISTS;
  
  	mutex_lock(&pci_acpi_pm_notify_mtx);
  
  	if (dev->wakeup.flags.notifier_present)
  		goto out;
  
  	status = acpi_install_notify_handler(dev->handle,
  					     ACPI_SYSTEM_NOTIFY,
  					     handler, context);
  	if (ACPI_FAILURE(status))
  		goto out;
  
  	dev->wakeup.flags.notifier_present = true;
  
   out:
  	mutex_unlock(&pci_acpi_pm_notify_mtx);
  	return status;
  }
  
  /**
   * remove_pm_notifier - Unregister PM notifier from given ACPI device.
   * @dev: ACPI device to remove the notifier from.
   */
  static acpi_status remove_pm_notifier(struct acpi_device *dev,
  				      acpi_notify_handler handler)
  {
  	acpi_status status = AE_BAD_PARAMETER;
  
  	mutex_lock(&pci_acpi_pm_notify_mtx);
  
  	if (!dev->wakeup.flags.notifier_present)
  		goto out;
  
  	status = acpi_remove_notify_handler(dev->handle,
  					    ACPI_SYSTEM_NOTIFY,
  					    handler);
  	if (ACPI_FAILURE(status))
  		goto out;
  
  	dev->wakeup.flags.notifier_present = false;
  
   out:
  	mutex_unlock(&pci_acpi_pm_notify_mtx);
  	return status;
  }
  
  /**
   * pci_acpi_add_bus_pm_notifier - Register PM notifier for given PCI bus.
   * @dev: ACPI device to add the notifier for.
   * @pci_bus: PCI bus to walk checking for PME status if an event is signaled.
   */
  acpi_status pci_acpi_add_bus_pm_notifier(struct acpi_device *dev,
  					 struct pci_bus *pci_bus)
  {
  	return add_pm_notifier(dev, pci_acpi_wake_bus, pci_bus);
  }
  
  /**
   * pci_acpi_remove_bus_pm_notifier - Unregister PCI bus PM notifier.
   * @dev: ACPI device to remove the notifier from.
   */
  acpi_status pci_acpi_remove_bus_pm_notifier(struct acpi_device *dev)
  {
  	return remove_pm_notifier(dev, pci_acpi_wake_bus);
  }
  
  /**
   * pci_acpi_add_pm_notifier - Register PM notifier for given PCI device.
   * @dev: ACPI device to add the notifier for.
   * @pci_dev: PCI device to check for the PME status if an event is signaled.
   */
  acpi_status pci_acpi_add_pm_notifier(struct acpi_device *dev,
  				     struct pci_dev *pci_dev)
  {
  	return add_pm_notifier(dev, pci_acpi_wake_dev, pci_dev);
  }
  
  /**
   * pci_acpi_remove_pm_notifier - Unregister PCI device PM notifier.
   * @dev: ACPI device to remove the notifier from.
   */
  acpi_status pci_acpi_remove_pm_notifier(struct acpi_device *dev)
  {
  	return remove_pm_notifier(dev, pci_acpi_wake_dev);
  }

  /*
   * _SxD returns the D-state with the highest power
   * (lowest D-state number) supported in the S-state "x".
   *
   * If the devices does not have a _PRW
   * (Power Resources for Wake) supporting system wakeup from "x"
   * then the OS is free to choose a lower power (higher number
   * D-state) than the return value from _SxD.
   *
   * But if _PRW is enabled at S-state "x", the OS
   * must not choose a power lower than _SxD --
   * unless the device has an _SxW method specifying
   * the lowest power (highest D-state number) the device
   * may enter while still able to wake the system.
   *
   * ie. depending on global OS policy:
   *
   * if (_PRW at S-state x)
   *	choose from highest power _SxD to lowest power _SxW
   * else // no _PRW at S-state x
   * 	choose highest power _SxD or any lower power

   */

  static pci_power_t acpi_pci_choose_state(struct pci_dev *pdev)

  {

  	int acpi_state;

  	acpi_state = acpi_pm_device_sleep_state(&pdev->dev, NULL);

  	if (acpi_state < 0)
  		return PCI_POWER_ERROR;
  
  	switch (acpi_state) {
  	case ACPI_STATE_D0:
  		return PCI_D0;
  	case ACPI_STATE_D1:
  		return PCI_D1;
  	case ACPI_STATE_D2:
  		return PCI_D2;
  	case ACPI_STATE_D3:
  		return PCI_D3hot;

  	case ACPI_STATE_D3_COLD:
  		return PCI_D3cold;

  	}
  	return PCI_POWER_ERROR;

  }

  
  static bool acpi_pci_power_manageable(struct pci_dev *dev)
  {
  	acpi_handle handle = DEVICE_ACPI_HANDLE(&dev->dev);
  
  	return handle ? acpi_bus_power_manageable(handle) : false;
  }

  static int acpi_pci_set_power_state(struct pci_dev *dev, pci_power_t state)
  {
  	acpi_handle handle = DEVICE_ACPI_HANDLE(&dev->dev);

  	acpi_handle tmp;

  	static const u8 state_conv[] = {
  		[PCI_D0] = ACPI_STATE_D0,
  		[PCI_D1] = ACPI_STATE_D1,
  		[PCI_D2] = ACPI_STATE_D2,
  		[PCI_D3hot] = ACPI_STATE_D3,
  		[PCI_D3cold] = ACPI_STATE_D3

  	};

  	int error = -EINVAL;

  	/* If the ACPI device has _EJ0, ignore the device */

  	if (!handle || ACPI_SUCCESS(acpi_get_handle(handle, "_EJ0", &tmp)))
  		return -ENODEV;

  
  	switch (state) {
  	case PCI_D0:
  	case PCI_D1:
  	case PCI_D2:
  	case PCI_D3hot:
  	case PCI_D3cold:

  		error = acpi_bus_set_power(handle, state_conv[state]);

  	}

  
  	if (!error)
  		dev_printk(KERN_INFO, &dev->dev,
  				"power state changed by ACPI to D%d
  ", state);
  
  	return error;

  }

  static bool acpi_pci_can_wakeup(struct pci_dev *dev)
  {
  	acpi_handle handle = DEVICE_ACPI_HANDLE(&dev->dev);
  
  	return handle ? acpi_bus_can_wakeup(handle) : false;
  }

  static void acpi_pci_propagate_wakeup_enable(struct pci_bus *bus, bool enable)
  {
  	while (bus->parent) {

  		if (!acpi_pm_device_sleep_wake(&bus->self->dev, enable))

  			return;
  		bus = bus->parent;
  	}
  
  	/* We have reached the root bus. */
  	if (bus->bridge)
  		acpi_pm_device_sleep_wake(bus->bridge, enable);
  }

  static int acpi_pci_sleep_wake(struct pci_dev *dev, bool enable)
  {

  	if (acpi_pci_can_wakeup(dev))
  		return acpi_pm_device_sleep_wake(&dev->dev, enable);

  	acpi_pci_propagate_wakeup_enable(dev->bus, enable);

  	return 0;

  }

  /**
   * acpi_dev_run_wake - Enable/disable wake-up for given device.
   * @phys_dev: Device to enable/disable the platform to wake-up the system for.
   * @enable: Whether enable or disable the wake-up functionality.
   *
   * Find the ACPI device object corresponding to @pci_dev and try to
   * enable/disable the GPE associated with it.
   */
  static int acpi_dev_run_wake(struct device *phys_dev, bool enable)
  {
  	struct acpi_device *dev;
  	acpi_handle handle;

  
  	if (!device_run_wake(phys_dev))
  		return -EINVAL;
  
  	handle = DEVICE_ACPI_HANDLE(phys_dev);
  	if (!handle || ACPI_FAILURE(acpi_bus_get_device(handle, &dev))) {
  		dev_dbg(phys_dev, "ACPI handle has no context in %s!
  ",
  			__func__);
  		return -ENODEV;
  	}
  
  	if (enable) {

  		acpi_enable_wakeup_device_power(dev, ACPI_STATE_S0);
  		acpi_enable_gpe(dev->wakeup.gpe_device, dev->wakeup.gpe_number);

  	} else {

  		acpi_disable_gpe(dev->wakeup.gpe_device, dev->wakeup.gpe_number);
  		acpi_disable_wakeup_device_power(dev);

  	}

  	return 0;

  }
  
  static void acpi_pci_propagate_run_wake(struct pci_bus *bus, bool enable)
  {
  	while (bus->parent) {
  		struct pci_dev *bridge = bus->self;
  
  		if (bridge->pme_interrupt)
  			return;
  		if (!acpi_dev_run_wake(&bridge->dev, enable))
  			return;
  		bus = bus->parent;
  	}
  
  	/* We have reached the root bus. */
  	if (bus->bridge)
  		acpi_dev_run_wake(bus->bridge, enable);
  }
  
  static int acpi_pci_run_wake(struct pci_dev *dev, bool enable)
  {
  	if (dev->pme_interrupt)
  		return 0;
  
  	if (!acpi_dev_run_wake(&dev->dev, enable))
  		return 0;
  
  	acpi_pci_propagate_run_wake(dev->bus, enable);
  	return 0;
  }

  static struct pci_platform_pm_ops acpi_pci_platform_pm = {
  	.is_manageable = acpi_pci_power_manageable,
  	.set_state = acpi_pci_set_power_state,
  	.choose_state = acpi_pci_choose_state,

  	.can_wakeup = acpi_pci_can_wakeup,
  	.sleep_wake = acpi_pci_sleep_wake,

  	.run_wake = acpi_pci_run_wake,

  };

  /* ACPI bus type */

  static int acpi_pci_find_device(struct device *dev, acpi_handle *handle)

  {
  	struct pci_dev * pci_dev;

  	u64	addr;

  
  	pci_dev = to_pci_dev(dev);
  	/* Please ref to ACPI spec for the syntax of _ADR */
  	addr = (PCI_SLOT(pci_dev->devfn) << 16) | PCI_FUNC(pci_dev->devfn);
  	*handle = acpi_get_child(DEVICE_ACPI_HANDLE(dev->parent), addr);
  	if (!*handle)
  		return -ENODEV;
  	return 0;
  }

  static int acpi_pci_find_root_bridge(struct device *dev, acpi_handle *handle)

  {
  	int num;
  	unsigned int seg, bus;
  
  	/*
  	 * The string should be the same as root bridge's name
  	 * Please look at 'pci_scan_bus_parented'
  	 */

  	num = sscanf(dev_name(dev), "pci%04x:%02x", &seg, &bus);

  	if (num != 2)
  		return -ENODEV;
  	*handle = acpi_get_pci_rootbridge_handle(seg, bus);
  	if (!*handle)
  		return -ENODEV;
  	return 0;
  }

  static struct acpi_bus_type acpi_pci_bus = {

  	.bus = &pci_bus_type,

  	.find_device = acpi_pci_find_device,
  	.find_bridge = acpi_pci_find_root_bridge,

  };

  static int __init acpi_pci_init(void)

  {
  	int ret;

  	if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_MSI) {

  		printk(KERN_INFO"ACPI FADT declares the system doesn't support MSI, so disable it
  ");
  		pci_no_msi();
  	}

  	if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_ASPM) {

  		printk(KERN_INFO"ACPI FADT declares the system doesn't support PCIe ASPM, so disable it
  ");
  		pcie_no_aspm();
  	}

  	ret = register_acpi_bus_type(&acpi_pci_bus);

  	if (ret)
  		return 0;

  	pci_set_platform_pm(&acpi_pci_platform_pm);

  	return 0;
  }

  arch_initcall(acpi_pci_init);