pci-acpi.c

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/*
 * File:    pci-acpi.c
 * Purpose: Provide PCI support in ACPI
 *
 * Copyright (C) 2005 David Shaohua Li <[email protected]>
 * Copyright (C) 2004 Tom Long Nguyen <[email protected]>
 * 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);

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);
}

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;
    }

    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);
}

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;
}

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;
}

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);
}

acpi_status pci_acpi_remove_bus_pm_notifier(struct acpi_device *dev)
{
    return remove_pm_notifier(dev, pci_acpi_wake_bus);
}

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);
}

acpi_status pci_acpi_remove_pm_notifier(struct acpi_device *dev)
{
    return 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,
        [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_info(&dev->dev, "power state changed by ACPI to %s\n",
             pci_power_name(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,
    .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_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);