/*
 * 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) {
                pci_wakeup_event(pci_dev);
                pci_check_pme_status(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;
        }
        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\n", 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;
        int error = -ENODEV;

        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!\n",
                        __func__);
                return -ENODEV;
        }

        if (enable) {
                if (!dev->wakeup.run_wake_count++) {
                        acpi_enable_wakeup_device_power(dev, ACPI_STATE_S0);
                        acpi_enable_gpe(dev->wakeup.gpe_device,
                                        dev->wakeup.gpe_number);
                }
        } else if (dev->wakeup.run_wake_count > 0) {
                if (!--dev->wakeup.run_wake_count) {
                        acpi_disable_gpe(dev->wakeup.gpe_device,
                                         dev->wakeup.gpe_number);
                        acpi_disable_wakeup_device_power(dev);
                }
        } else {
                error = -EALREADY;
        }

        return error;
}

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\n");
                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\n");
                pcie_clear_aspm();
                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);