/*
 * 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 <linux/pm_qos.h>
#include "pci.h"

/**
 * 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->current_state == PCI_D3cold) {
                pci_wakeup_event(pci_dev);
                pm_runtime_resume(&pci_dev->dev);
                return;
        }

        /* Clear PME Status if set. */
        if (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);
}

/**
 * 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 acpi_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 acpi_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 acpi_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 acpi_remove_pm_notifier(dev, pci_acpi_wake_dev);
}

phys_addr_t acpi_pci_root_get_mcfg_addr(acpi_handle handle)
{
        acpi_status status = AE_NOT_EXIST;
        unsigned long long mcfg_addr;

        if (handle)
                status = acpi_evaluate_integer(handle, METHOD_NAME__CBA,
                                               NULL, &mcfg_addr);
        if (ACPI_FAILURE(status))
                return 0;

        return (phys_addr_t)mcfg_addr;
}

/*
 * _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, d_max;

        if (pdev->no_d3cold)
                d_max = ACPI_STATE_D3_HOT;
        else
                d_max = ACPI_STATE_D3_COLD;
        acpi_state = acpi_pm_device_sleep_state(&pdev->dev, NULL, d_max);
        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_HOT:
                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_COLD,
                [PCI_D3cold] = ACPI_STATE_D3_COLD,
        };
        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_D3cold:
                if (dev_pm_qos_flags(&dev->dev, PM_QOS_FLAG_NO_POWER_OFF) ==
                                PM_QOS_FLAGS_ALL) {
                        error = -EBUSY;
                        break;
                }
        case PCI_D0:
        case PCI_D1:
        case PCI_D2:
        case PCI_D3hot:
                error = acpi_bus_set_power(handle, state_conv[state]);
        }

        if (!error)
                dev_info(&dev->dev, "power state changed by ACPI to %s\n",
                         acpi_power_state_string(state_conv[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;
}

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_pm_device_run_wake(&bridge->dev, enable))
                        return;
                bus = bus->parent;
        }

        /* We have reached the root bus. */
        if (bus->bridge)
                acpi_pm_device_run_wake(bus->bridge, enable);
}

static int acpi_pci_run_wake(struct pci_dev *dev, bool enable)
{
        /*
         * Per PCI Express Base Specification Revision 2.0 section
         * 5.3.3.2 Link Wakeup, platform support is needed for D3cold
         * waking up to power on the main link even if there is PME
         * support for D3cold
         */
        if (dev->pme_interrupt && !dev->runtime_d3cold)
                return 0;

        if (!acpi_pm_device_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,
        .sleep_wake = acpi_pci_sleep_wake,
        .run_wake = acpi_pci_run_wake,
};

void acpi_pci_add_bus(struct pci_bus *bus)
{
        acpi_handle handle = NULL;

        if (bus->bridge)
                handle = ACPI_HANDLE(bus->bridge);
        if (acpi_pci_disabled || handle == NULL)
                return;

        acpi_pci_slot_enumerate(bus, handle);
        acpiphp_enumerate_slots(bus, handle);
}

void acpi_pci_remove_bus(struct pci_bus *bus)
{
        /*
         * bus->bridge->acpi_node.handle has already been reset to NULL
         * when acpi_pci_remove_bus() is called, so don't check ACPI handle.
         */
        if (acpi_pci_disabled)
                return;

        acpiphp_remove_slots(bus);
        acpi_pci_slot_remove(bus);
}

/* ACPI bus type */
static int acpi_pci_find_device(struct device *dev, acpi_handle *handle)
{
        struct pci_dev *pci_dev = to_pci_dev(dev);
        bool is_bridge;
        u64 addr;

        /*
         * pci_is_bridge() is not suitable here, because pci_dev->subordinate
         * is set only after acpi_pci_find_device() has been called for the
         * given device.
         */
        is_bridge = pci_dev->hdr_type == PCI_HEADER_TYPE_BRIDGE
                        || pci_dev->hdr_type == PCI_HEADER_TYPE_CARDBUS;
        /* Please ref to ACPI spec for the syntax of _ADR */
        addr = (PCI_SLOT(pci_dev->devfn) << 16) | PCI_FUNC(pci_dev->devfn);
        *handle = acpi_find_child(ACPI_HANDLE(dev->parent), addr, is_bridge);
        if (!*handle)
                return -ENODEV;
        return 0;
}

static void pci_acpi_setup(struct device *dev)
{
        struct pci_dev *pci_dev = to_pci_dev(dev);
        acpi_handle handle = ACPI_HANDLE(dev);
        struct acpi_device *adev;

        if (acpi_bus_get_device(handle, &adev) || !adev->wakeup.flags.valid)
                return;

        device_set_wakeup_capable(dev, true);
        acpi_pci_sleep_wake(pci_dev, false);

        pci_acpi_add_pm_notifier(adev, pci_dev);
        if (adev->wakeup.flags.run_wake)
                device_set_run_wake(dev, true);
}

static void pci_acpi_cleanup(struct device *dev)
{
        acpi_handle handle = ACPI_HANDLE(dev);
        struct acpi_device *adev;

        if (!acpi_bus_get_device(handle, &adev) && adev->wakeup.flags.valid) {
                device_set_wakeup_capable(dev, false);
                device_set_run_wake(dev, false);
                pci_acpi_remove_pm_notifier(adev);
        }
}

static bool pci_acpi_bus_match(struct device *dev)
{
        return dev->bus == &pci_bus_type;
}

static struct acpi_bus_type acpi_pci_bus = {
        .name = "PCI",
        .match = pci_acpi_bus_match,
        .find_device = acpi_pci_find_device,
        .setup = pci_acpi_setup,
        .cleanup = pci_acpi_cleanup,
};

static int __init acpi_pci_init(void)
{
        int ret;

        if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_MSI) {
                pr_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) {
                pr_info("ACPI FADT declares the system doesn't support PCIe ASPM, so disable it\n");
                pcie_no_aspm();
        }

        ret = register_acpi_bus_type(&acpi_pci_bus);
        if (ret)
                return 0;

        pci_set_platform_pm(&acpi_pci_platform_pm);
        acpi_pci_slot_init();
        acpiphp_init();

        return 0;
}
arch_initcall(acpi_pci_init);