LXR linux/drivers/pci/pci-acpi.c

   1/*
   2 * File:        pci-acpi.c
   3 * Purpose:     Provide PCI support in ACPI
   4 *
   5 * Copyright (C) 2005 David Shaohua Li <shaohua.li@intel.com>
   6 * Copyright (C) 2004 Tom Long Nguyen <tom.l.nguyen@intel.com>
   7 * Copyright (C) 2004 Intel Corp.
   8 */
   9
  10#include <linux/delay.h>
  11#include <linux/init.h>
  12#include <linux/pci.h>
  13#include <linux/module.h>
  14#include <linux/pci-aspm.h>
  15#include <acpi/acpi.h>
  16#include <acpi/acpi_bus.h>
  17
  18#include <linux/pci-acpi.h>
  19#include "pci.h"
  20
  21/*
  22 * _SxD returns the D-state with the highest power
  23 * (lowest D-state number) supported in the S-state "x".
  24 *
  25 * If the devices does not have a _PRW
  26 * (Power Resources for Wake) supporting system wakeup from "x"
  27 * then the OS is free to choose a lower power (higher number
  28 * D-state) than the return value from _SxD.
  29 *
  30 * But if _PRW is enabled at S-state "x", the OS
  31 * must not choose a power lower than _SxD --
  32 * unless the device has an _SxW method specifying
  33 * the lowest power (highest D-state number) the device
  34 * may enter while still able to wake the system.
  35 *
  36 * ie. depending on global OS policy:
  37 *
  38 * if (_PRW at S-state x)
  39 *      choose from highest power _SxD to lowest power _SxW
  40 * else // no _PRW at S-state x
  41 *      choose highest power _SxD or any lower power
  42 */
  43
  44static pci_power_t acpi_pci_choose_state(struct pci_dev *pdev)
  45{
  46        int acpi_state;
  47
  48        acpi_state = acpi_pm_device_sleep_state(&pdev->dev, NULL);
  49        if (acpi_state < 0)
  50                return PCI_POWER_ERROR;
  51
  52        switch (acpi_state) {
  53        case ACPI_STATE_D0:
  54                return PCI_D0;
  55        case ACPI_STATE_D1:
  56                return PCI_D1;
  57        case ACPI_STATE_D2:
  58                return PCI_D2;
  59        case ACPI_STATE_D3:
  60                return PCI_D3hot;
  61        }
  62        return PCI_POWER_ERROR;
  63}
  64
  65static bool acpi_pci_power_manageable(struct pci_dev *dev)
  66{
  67        acpi_handle handle = DEVICE_ACPI_HANDLE(&dev->dev);
  68
  69        return handle ? acpi_bus_power_manageable(handle) : false;
  70}
  71
  72static int acpi_pci_set_power_state(struct pci_dev *dev, pci_power_t state)
  73{
  74        acpi_handle handle = DEVICE_ACPI_HANDLE(&dev->dev);
  75        acpi_handle tmp;
  76        static const u8 state_conv[] = {
  77                [PCI_D0] = ACPI_STATE_D0,
  78                [PCI_D1] = ACPI_STATE_D1,
  79                [PCI_D2] = ACPI_STATE_D2,
  80                [PCI_D3hot] = ACPI_STATE_D3,
  81                [PCI_D3cold] = ACPI_STATE_D3
  82        };
  83        int error = -EINVAL;
  84
  85        /* If the ACPI device has _EJ0, ignore the device */
  86        if (!handle || ACPI_SUCCESS(acpi_get_handle(handle, "_EJ0", &tmp)))
  87                return -ENODEV;
  88
  89        switch (state) {
  90        case PCI_D0:
  91        case PCI_D1:
  92        case PCI_D2:
  93        case PCI_D3hot:
  94        case PCI_D3cold:
  95                error = acpi_bus_set_power(handle, state_conv[state]);
  96        }
  97
  98        if (!error)
  99                dev_printk(KERN_INFO, &dev->dev,
 100                                "power state changed by ACPI to D%d\n", state);
 101
 102        return error;
 103}
 104
 105static bool acpi_pci_can_wakeup(struct pci_dev *dev)
 106{
 107        acpi_handle handle = DEVICE_ACPI_HANDLE(&dev->dev);
 108
 109        return handle ? acpi_bus_can_wakeup(handle) : false;
 110}
 111
 112static int acpi_pci_sleep_wake(struct pci_dev *dev, bool enable)
 113{
 114        int error = acpi_pm_device_sleep_wake(&dev->dev, enable);
 115
 116        if (!error)
 117                dev_printk(KERN_INFO, &dev->dev,
 118                                "wake-up capability %s by ACPI\n",
 119                                enable ? "enabled" : "disabled");
 120        return error;
 121}
 122
 123static struct pci_platform_pm_ops acpi_pci_platform_pm = {
 124        .is_manageable = acpi_pci_power_manageable,
 125        .set_state = acpi_pci_set_power_state,
 126        .choose_state = acpi_pci_choose_state,
 127        .can_wakeup = acpi_pci_can_wakeup,
 128        .sleep_wake = acpi_pci_sleep_wake,
 129};
 130
 131/* ACPI bus type */
 132static int acpi_pci_find_device(struct device *dev, acpi_handle *handle)
 133{
 134        struct pci_dev * pci_dev;
 135        acpi_integer    addr;
 136
 137        pci_dev = to_pci_dev(dev);
 138        /* Please ref to ACPI spec for the syntax of _ADR */
 139        addr = (PCI_SLOT(pci_dev->devfn) << 16) | PCI_FUNC(pci_dev->devfn);
 140        *handle = acpi_get_child(DEVICE_ACPI_HANDLE(dev->parent), addr);
 141        if (!*handle)
 142                return -ENODEV;
 143        return 0;
 144}
 145
 146static int acpi_pci_find_root_bridge(struct device *dev, acpi_handle *handle)
 147{
 148        int num;
 149        unsigned int seg, bus;
 150
 151        /*
 152         * The string should be the same as root bridge's name
 153         * Please look at 'pci_scan_bus_parented'
 154         */
 155        num = sscanf(dev_name(dev), "pci%04x:%02x", &seg, &bus);
 156        if (num != 2)
 157                return -ENODEV;
 158        *handle = acpi_get_pci_rootbridge_handle(seg, bus);
 159        if (!*handle)
 160                return -ENODEV;
 161        return 0;
 162}
 163
 164static struct acpi_bus_type acpi_pci_bus = {
 165        .bus = &pci_bus_type,
 166        .find_device = acpi_pci_find_device,
 167        .find_bridge = acpi_pci_find_root_bridge,
 168};
 169
 170static int __init acpi_pci_init(void)
 171{
 172        int ret;
 173
 174        if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_MSI) {
 175                printk(KERN_INFO"ACPI FADT declares the system doesn't support MSI, so disable it\n");
 176                pci_no_msi();
 177        }
 178
 179        if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_ASPM) {
 180                printk(KERN_INFO"ACPI FADT declares the system doesn't support PCIe ASPM, so disable it\n");
 181                pcie_no_aspm();
 182        }
 183
 184        ret = register_acpi_bus_type(&acpi_pci_bus);
 185        if (ret)
 186                return 0;
 187        pci_set_platform_pm(&acpi_pci_platform_pm);
 188        return 0;
 189}
 190arch_initcall(acpi_pci_init);
 191