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