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
  44 static 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
  65 static 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
  72 static 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
 105 static 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
 112 static 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
 123 static 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 */
 132 static 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
 146 static 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
 164 static 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
 170 static 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 }
 190 arch_initcall(acpi_pci_init);