linux/drivers/pci/pci-acpi.c
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   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 <linux/pm_runtime.h>
  20#include "pci.h"
  21
  22static DEFINE_MUTEX(pci_acpi_pm_notify_mtx);
  23
  24/**
  25 * pci_acpi_wake_bus - Wake-up notification handler for root buses.
  26 * @handle: ACPI handle of a device the notification is for.
  27 * @event: Type of the signaled event.
  28 * @context: PCI root bus to wake up devices on.
  29 */
  30static void pci_acpi_wake_bus(acpi_handle handle, u32 event, void *context)
  31{
  32        struct pci_bus *pci_bus = context;
  33
  34        if (event == ACPI_NOTIFY_DEVICE_WAKE && pci_bus)
  35                pci_pme_wakeup_bus(pci_bus);
  36}
  37
  38/**
  39 * pci_acpi_wake_dev - Wake-up notification handler for PCI devices.
  40 * @handle: ACPI handle of a device the notification is for.
  41 * @event: Type of the signaled event.
  42 * @context: PCI device object to wake up.
  43 */
  44static void pci_acpi_wake_dev(acpi_handle handle, u32 event, void *context)
  45{
  46        struct pci_dev *pci_dev = context;
  47
  48        if (event != ACPI_NOTIFY_DEVICE_WAKE || !pci_dev)
  49                return;
  50
  51        if (!pci_dev->pm_cap || !pci_dev->pme_support
  52             || pci_check_pme_status(pci_dev)) {
  53                if (pci_dev->pme_poll)
  54                        pci_dev->pme_poll = false;
  55
  56                pci_wakeup_event(pci_dev);
  57                pm_runtime_resume(&pci_dev->dev);
  58        }
  59
  60        if (pci_dev->subordinate)
  61                pci_pme_wakeup_bus(pci_dev->subordinate);
  62}
  63
  64/**
  65 * add_pm_notifier - Register PM notifier for given ACPI device.
  66 * @dev: ACPI device to add the notifier for.
  67 * @context: PCI device or bus to check for PME status if an event is signaled.
  68 *
  69 * NOTE: @dev need not be a run-wake or wake-up device to be a valid source of
  70 * PM wake-up events.  For example, wake-up events may be generated for bridges
  71 * if one of the devices below the bridge is signaling PME, even if the bridge
  72 * itself doesn't have a wake-up GPE associated with it.
  73 */
  74static acpi_status add_pm_notifier(struct acpi_device *dev,
  75                                   acpi_notify_handler handler,
  76                                   void *context)
  77{
  78        acpi_status status = AE_ALREADY_EXISTS;
  79
  80        mutex_lock(&pci_acpi_pm_notify_mtx);
  81
  82        if (dev->wakeup.flags.notifier_present)
  83                goto out;
  84
  85        status = acpi_install_notify_handler(dev->handle,
  86                                             ACPI_SYSTEM_NOTIFY,
  87                                             handler, context);
  88        if (ACPI_FAILURE(status))
  89                goto out;
  90
  91        dev->wakeup.flags.notifier_present = true;
  92
  93 out:
  94        mutex_unlock(&pci_acpi_pm_notify_mtx);
  95        return status;
  96}
  97
  98/**
  99 * remove_pm_notifier - Unregister PM notifier from given ACPI device.
 100 * @dev: ACPI device to remove the notifier from.
 101 */
 102static acpi_status remove_pm_notifier(struct acpi_device *dev,
 103                                      acpi_notify_handler handler)
 104{
 105        acpi_status status = AE_BAD_PARAMETER;
 106
 107        mutex_lock(&pci_acpi_pm_notify_mtx);
 108
 109        if (!dev->wakeup.flags.notifier_present)
 110                goto out;
 111
 112        status = acpi_remove_notify_handler(dev->handle,
 113                                            ACPI_SYSTEM_NOTIFY,
 114                                            handler);
 115        if (ACPI_FAILURE(status))
 116                goto out;
 117
 118        dev->wakeup.flags.notifier_present = false;
 119
 120 out:
 121        mutex_unlock(&pci_acpi_pm_notify_mtx);
 122        return status;
 123}
 124
 125/**
 126 * pci_acpi_add_bus_pm_notifier - Register PM notifier for given PCI bus.
 127 * @dev: ACPI device to add the notifier for.
 128 * @pci_bus: PCI bus to walk checking for PME status if an event is signaled.
 129 */
 130acpi_status pci_acpi_add_bus_pm_notifier(struct acpi_device *dev,
 131                                         struct pci_bus *pci_bus)
 132{
 133        return add_pm_notifier(dev, pci_acpi_wake_bus, pci_bus);
 134}
 135
 136/**
 137 * pci_acpi_remove_bus_pm_notifier - Unregister PCI bus PM notifier.
 138 * @dev: ACPI device to remove the notifier from.
 139 */
 140acpi_status pci_acpi_remove_bus_pm_notifier(struct acpi_device *dev)
 141{
 142        return remove_pm_notifier(dev, pci_acpi_wake_bus);
 143}
 144
 145/**
 146 * pci_acpi_add_pm_notifier - Register PM notifier for given PCI device.
 147 * @dev: ACPI device to add the notifier for.
 148 * @pci_dev: PCI device to check for the PME status if an event is signaled.
 149 */
 150acpi_status pci_acpi_add_pm_notifier(struct acpi_device *dev,
 151                                     struct pci_dev *pci_dev)
 152{
 153        return add_pm_notifier(dev, pci_acpi_wake_dev, pci_dev);
 154}
 155
 156/**
 157 * pci_acpi_remove_pm_notifier - Unregister PCI device PM notifier.
 158 * @dev: ACPI device to remove the notifier from.
 159 */
 160acpi_status pci_acpi_remove_pm_notifier(struct acpi_device *dev)
 161{
 162        return remove_pm_notifier(dev, pci_acpi_wake_dev);
 163}
 164
 165/*
 166 * _SxD returns the D-state with the highest power
 167 * (lowest D-state number) supported in the S-state "x".
 168 *
 169 * If the devices does not have a _PRW
 170 * (Power Resources for Wake) supporting system wakeup from "x"
 171 * then the OS is free to choose a lower power (higher number
 172 * D-state) than the return value from _SxD.
 173 *
 174 * But if _PRW is enabled at S-state "x", the OS
 175 * must not choose a power lower than _SxD --
 176 * unless the device has an _SxW method specifying
 177 * the lowest power (highest D-state number) the device
 178 * may enter while still able to wake the system.
 179 *
 180 * ie. depending on global OS policy:
 181 *
 182 * if (_PRW at S-state x)
 183 *      choose from highest power _SxD to lowest power _SxW
 184 * else // no _PRW at S-state x
 185 *      choose highest power _SxD or any lower power
 186 */
 187
 188static pci_power_t acpi_pci_choose_state(struct pci_dev *pdev)
 189{
 190        int acpi_state;
 191
 192        acpi_state = acpi_pm_device_sleep_state(&pdev->dev, NULL);
 193        if (acpi_state < 0)
 194                return PCI_POWER_ERROR;
 195
 196        switch (acpi_state) {
 197        case ACPI_STATE_D0:
 198                return PCI_D0;
 199        case ACPI_STATE_D1:
 200                return PCI_D1;
 201        case ACPI_STATE_D2:
 202                return PCI_D2;
 203        case ACPI_STATE_D3:
 204                return PCI_D3hot;
 205        case ACPI_STATE_D3_COLD:
 206                return PCI_D3cold;
 207        }
 208        return PCI_POWER_ERROR;
 209}
 210
 211static bool acpi_pci_power_manageable(struct pci_dev *dev)
 212{
 213        acpi_handle handle = DEVICE_ACPI_HANDLE(&dev->dev);
 214
 215        return handle ? acpi_bus_power_manageable(handle) : false;
 216}
 217
 218static int acpi_pci_set_power_state(struct pci_dev *dev, pci_power_t state)
 219{
 220        acpi_handle handle = DEVICE_ACPI_HANDLE(&dev->dev);
 221        acpi_handle tmp;
 222        static const u8 state_conv[] = {
 223                [PCI_D0] = ACPI_STATE_D0,
 224                [PCI_D1] = ACPI_STATE_D1,
 225                [PCI_D2] = ACPI_STATE_D2,
 226                [PCI_D3hot] = ACPI_STATE_D3,
 227                [PCI_D3cold] = ACPI_STATE_D3
 228        };
 229        int error = -EINVAL;
 230
 231        /* If the ACPI device has _EJ0, ignore the device */
 232        if (!handle || ACPI_SUCCESS(acpi_get_handle(handle, "_EJ0", &tmp)))
 233                return -ENODEV;
 234
 235        switch (state) {
 236        case PCI_D0:
 237        case PCI_D1:
 238        case PCI_D2:
 239        case PCI_D3hot:
 240        case PCI_D3cold:
 241                error = acpi_bus_set_power(handle, state_conv[state]);
 242        }
 243
 244        if (!error)
 245                dev_printk(KERN_INFO, &dev->dev,
 246                                "power state changed by ACPI to D%d\n", state);
 247
 248        return error;
 249}
 250
 251static bool acpi_pci_can_wakeup(struct pci_dev *dev)
 252{
 253        acpi_handle handle = DEVICE_ACPI_HANDLE(&dev->dev);
 254
 255        return handle ? acpi_bus_can_wakeup(handle) : false;
 256}
 257
 258static void acpi_pci_propagate_wakeup_enable(struct pci_bus *bus, bool enable)
 259{
 260        while (bus->parent) {
 261                if (!acpi_pm_device_sleep_wake(&bus->self->dev, enable))
 262                        return;
 263                bus = bus->parent;
 264        }
 265
 266        /* We have reached the root bus. */
 267        if (bus->bridge)
 268                acpi_pm_device_sleep_wake(bus->bridge, enable);
 269}
 270
 271static int acpi_pci_sleep_wake(struct pci_dev *dev, bool enable)
 272{
 273        if (acpi_pci_can_wakeup(dev))
 274                return acpi_pm_device_sleep_wake(&dev->dev, enable);
 275
 276        acpi_pci_propagate_wakeup_enable(dev->bus, enable);
 277        return 0;
 278}
 279
 280/**
 281 * acpi_dev_run_wake - Enable/disable wake-up for given device.
 282 * @phys_dev: Device to enable/disable the platform to wake-up the system for.
 283 * @enable: Whether enable or disable the wake-up functionality.
 284 *
 285 * Find the ACPI device object corresponding to @pci_dev and try to
 286 * enable/disable the GPE associated with it.
 287 */
 288static int acpi_dev_run_wake(struct device *phys_dev, bool enable)
 289{
 290        struct acpi_device *dev;
 291        acpi_handle handle;
 292
 293        if (!device_run_wake(phys_dev))
 294                return -EINVAL;
 295
 296        handle = DEVICE_ACPI_HANDLE(phys_dev);
 297        if (!handle || ACPI_FAILURE(acpi_bus_get_device(handle, &dev))) {
 298                dev_dbg(phys_dev, "ACPI handle has no context in %s!\n",
 299                        __func__);
 300                return -ENODEV;
 301        }
 302
 303        if (enable) {
 304                acpi_enable_wakeup_device_power(dev, ACPI_STATE_S0);
 305                acpi_enable_gpe(dev->wakeup.gpe_device, dev->wakeup.gpe_number);
 306        } else {
 307                acpi_disable_gpe(dev->wakeup.gpe_device, dev->wakeup.gpe_number);
 308                acpi_disable_wakeup_device_power(dev);
 309        }
 310
 311        return 0;
 312}
 313
 314static void acpi_pci_propagate_run_wake(struct pci_bus *bus, bool enable)
 315{
 316        while (bus->parent) {
 317                struct pci_dev *bridge = bus->self;
 318
 319                if (bridge->pme_interrupt)
 320                        return;
 321                if (!acpi_dev_run_wake(&bridge->dev, enable))
 322                        return;
 323                bus = bus->parent;
 324        }
 325
 326        /* We have reached the root bus. */
 327        if (bus->bridge)
 328                acpi_dev_run_wake(bus->bridge, enable);
 329}
 330
 331static int acpi_pci_run_wake(struct pci_dev *dev, bool enable)
 332{
 333        if (dev->pme_interrupt)
 334                return 0;
 335
 336        if (!acpi_dev_run_wake(&dev->dev, enable))
 337                return 0;
 338
 339        acpi_pci_propagate_run_wake(dev->bus, enable);
 340        return 0;
 341}
 342
 343static struct pci_platform_pm_ops acpi_pci_platform_pm = {
 344        .is_manageable = acpi_pci_power_manageable,
 345        .set_state = acpi_pci_set_power_state,
 346        .choose_state = acpi_pci_choose_state,
 347        .can_wakeup = acpi_pci_can_wakeup,
 348        .sleep_wake = acpi_pci_sleep_wake,
 349        .run_wake = acpi_pci_run_wake,
 350};
 351
 352/* ACPI bus type */
 353static int acpi_pci_find_device(struct device *dev, acpi_handle *handle)
 354{
 355        struct pci_dev * pci_dev;
 356        u64     addr;
 357
 358        pci_dev = to_pci_dev(dev);
 359        /* Please ref to ACPI spec for the syntax of _ADR */
 360        addr = (PCI_SLOT(pci_dev->devfn) << 16) | PCI_FUNC(pci_dev->devfn);
 361        *handle = acpi_get_child(DEVICE_ACPI_HANDLE(dev->parent), addr);
 362        if (!*handle)
 363                return -ENODEV;
 364        return 0;
 365}
 366
 367static int acpi_pci_find_root_bridge(struct device *dev, acpi_handle *handle)
 368{
 369        int num;
 370        unsigned int seg, bus;
 371
 372        /*
 373         * The string should be the same as root bridge's name
 374         * Please look at 'pci_scan_bus_parented'
 375         */
 376        num = sscanf(dev_name(dev), "pci%04x:%02x", &seg, &bus);
 377        if (num != 2)
 378                return -ENODEV;
 379        *handle = acpi_get_pci_rootbridge_handle(seg, bus);
 380        if (!*handle)
 381                return -ENODEV;
 382        return 0;
 383}
 384
 385static struct acpi_bus_type acpi_pci_bus = {
 386        .bus = &pci_bus_type,
 387        .find_device = acpi_pci_find_device,
 388        .find_bridge = acpi_pci_find_root_bridge,
 389};
 390
 391static int __init acpi_pci_init(void)
 392{
 393        int ret;
 394
 395        if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_MSI) {
 396                printk(KERN_INFO"ACPI FADT declares the system doesn't support MSI, so disable it\n");
 397                pci_no_msi();
 398        }
 399
 400        if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_ASPM) {
 401                printk(KERN_INFO"ACPI FADT declares the system doesn't support PCIe ASPM, so disable it\n");
 402                pcie_no_aspm();
 403        }
 404
 405        ret = register_acpi_bus_type(&acpi_pci_bus);
 406        if (ret)
 407                return 0;
 408        pci_set_platform_pm(&acpi_pci_platform_pm);
 409        return 0;
 410}
 411arch_initcall(acpi_pci_init);
 412