drivers/pci/pcie/pme.c

   1 /*
   2  * PCIe Native PME support
   3  *
   4  * Copyright (C) 2007 - 2009 Intel Corp
   5  * Copyright (C) 2007 - 2009 Shaohua Li <shaohua.li@intel.com>
   6  * Copyright (C) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
   7  *
   8  * This file is subject to the terms and conditions of the GNU General Public
   9  * License V2.  See the file "COPYING" in the main directory of this archive
  10  * for more details.
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/pci.h>
  15 #include <linux/kernel.h>
  16 #include <linux/errno.h>
  17 #include <linux/slab.h>
  18 #include <linux/init.h>
  19 #include <linux/interrupt.h>
  20 #include <linux/device.h>
  21 #include <linux/pcieport_if.h>
  22 #include <linux/pm_runtime.h>
  23
  24 #include "../pci.h"
  25 #include "portdrv.h"
  26
  27 /*
  28  * If this switch is set, MSI will not be used for PCIe PME signaling.  This
  29  * causes the PCIe port driver to use INTx interrupts only, but it turns out
  30  * that using MSI for PCIe PME signaling doesn't play well with PCIe PME-based
  31  * wake-up from system sleep states.
  32  */
  33 bool pcie_pme_msi_disabled;
  34
  35 static int __init pcie_pme_setup(char *str)
  36 {
  37         if (!strncmp(str, "nomsi", 5))
  38                 pcie_pme_msi_disabled = true;
  39
  40         return 1;
  41 }
  42 __setup("pcie_pme=", pcie_pme_setup);
  43
  44 struct pcie_pme_service_data {
  45         spinlock_t lock;
  46         struct pcie_device *srv;
  47         struct work_struct work;
  48         bool noirq; /* Don't enable the PME interrupt used by this service. */
  49 };
  50
  51 /**
  52  * pcie_pme_interrupt_enable - Enable/disable PCIe PME interrupt generation.
  53  * @dev: PCIe root port or event collector.
  54  * @enable: Enable or disable the interrupt.
  55  */
  56 void pcie_pme_interrupt_enable(struct pci_dev *dev, bool enable)
  57 {
  58         if (enable)
  59                 pcie_capability_set_word(dev, PCI_EXP_RTCTL,
  60                                          PCI_EXP_RTCTL_PMEIE);
  61         else
  62                 pcie_capability_clear_word(dev, PCI_EXP_RTCTL,
  63                                            PCI_EXP_RTCTL_PMEIE);
  64 }
  65
  66 /**
  67  * pcie_pme_walk_bus - Scan a PCI bus for devices asserting PME#.
  68  * @bus: PCI bus to scan.
  69  *
  70  * Scan given PCI bus and all buses under it for devices asserting PME#.
  71  */
  72 static bool pcie_pme_walk_bus(struct pci_bus *bus)
  73 {
  74         struct pci_dev *dev;
  75         bool ret = false;
  76
  77         list_for_each_entry(dev, &bus->devices, bus_list) {
  78                 /* Skip PCIe devices in case we started from a root port. */
  79                 if (!pci_is_pcie(dev) && pci_check_pme_status(dev)) {
  80                         if (dev->pme_poll)
  81                                 dev->pme_poll = false;
  82
  83                         pci_wakeup_event(dev);
  84                         pm_request_resume(&dev->dev);
  85                         ret = true;
  86                 }
  87
  88                 if (dev->subordinate && pcie_pme_walk_bus(dev->subordinate))
  89                         ret = true;
  90         }
  91
  92         return ret;
  93 }
  94
  95 /**
  96  * pcie_pme_from_pci_bridge - Check if PCIe-PCI bridge generated a PME.
  97  * @bus: Secondary bus of the bridge.
  98  * @devfn: Device/function number to check.
  99  *
 100  * PME from PCI devices under a PCIe-PCI bridge may be converted to an in-band
 101  * PCIe PME message.  In such that case the bridge should use the Requester ID
 102  * of device/function number 0 on its secondary bus.
 103  */
 104 static bool pcie_pme_from_pci_bridge(struct pci_bus *bus, u8 devfn)
 105 {
 106         struct pci_dev *dev;
 107         bool found = false;
 108
 109         if (devfn)
 110                 return false;
 111
 112         dev = pci_dev_get(bus->self);
 113         if (!dev)
 114                 return false;
 115
 116         if (pci_is_pcie(dev) && pci_pcie_type(dev) == PCI_EXP_TYPE_PCI_BRIDGE) {
 117                 down_read(&pci_bus_sem);
 118                 if (pcie_pme_walk_bus(bus))
 119                         found = true;
 120                 up_read(&pci_bus_sem);
 121         }
 122
 123         pci_dev_put(dev);
 124         return found;
 125 }
 126
 127 /**
 128  * pcie_pme_handle_request - Find device that generated PME and handle it.
 129  * @port: Root port or event collector that generated the PME interrupt.
 130  * @req_id: PCIe Requester ID of the device that generated the PME.
 131  */
 132 static void pcie_pme_handle_request(struct pci_dev *port, u16 req_id)
 133 {
 134         u8 busnr = req_id >> 8, devfn = req_id & 0xff;
 135         struct pci_bus *bus;
 136         struct pci_dev *dev;
 137         bool found = false;
 138
 139         /* First, check if the PME is from the root port itself. */
 140         if (port->devfn == devfn && port->bus->number == busnr) {
 141                 if (port->pme_poll)
 142                         port->pme_poll = false;
 143
 144                 if (pci_check_pme_status(port)) {
 145                         pm_request_resume(&port->dev);
 146                         found = true;
 147                 } else {
 148                         /*
 149                          * Apparently, the root port generated the PME on behalf
 150                          * of a non-PCIe device downstream.  If this is done by
 151                          * a root port, the Requester ID field in its status
 152                          * register may contain either the root port's, or the
 153                          * source device's information (PCI Express Base
 154                          * Specification, Rev. 2.0, Section 6.1.9).
 155                          */
 156                         down_read(&pci_bus_sem);
 157                         found = pcie_pme_walk_bus(port->subordinate);
 158                         up_read(&pci_bus_sem);
 159                 }
 160                 goto out;
 161         }
 162
 163         /* Second, find the bus the source device is on. */
 164         bus = pci_find_bus(pci_domain_nr(port->bus), busnr);
 165         if (!bus)
 166                 goto out;
 167
 168         /* Next, check if the PME is from a PCIe-PCI bridge. */
 169         found = pcie_pme_from_pci_bridge(bus, devfn);
 170         if (found)
 171                 goto out;
 172
 173         /* Finally, try to find the PME source on the bus. */
 174         down_read(&pci_bus_sem);
 175         list_for_each_entry(dev, &bus->devices, bus_list) {
 176                 pci_dev_get(dev);
 177                 if (dev->devfn == devfn) {
 178                         found = true;
 179                         break;
 180                 }
 181                 pci_dev_put(dev);
 182         }
 183         up_read(&pci_bus_sem);
 184
 185         if (found) {
 186                 /* The device is there, but we have to check its PME status. */
 187                 found = pci_check_pme_status(dev);
 188                 if (found) {
 189                         if (dev->pme_poll)
 190                                 dev->pme_poll = false;
 191
 192                         pci_wakeup_event(dev);
 193                         pm_request_resume(&dev->dev);
 194                 }
 195                 pci_dev_put(dev);
 196         } else if (devfn) {
 197                 /*
 198                  * The device is not there, but we can still try to recover by
 199                  * assuming that the PME was reported by a PCIe-PCI bridge that
 200                  * used devfn different from zero.
 201                  */
 202                 dev_dbg(&port->dev, "PME interrupt generated for non-existent device %02x:%02x.%d\n",
 203                         busnr, PCI_SLOT(devfn), PCI_FUNC(devfn));
 204                 found = pcie_pme_from_pci_bridge(bus, 0);
 205         }
 206
 207  out:
 208         if (!found)
 209                 dev_dbg(&port->dev, "Spurious native PME interrupt!\n");
 210 }
 211
 212 /**
 213  * pcie_pme_work_fn - Work handler for PCIe PME interrupt.
 214  * @work: Work structure giving access to service data.
 215  */
 216 static void pcie_pme_work_fn(struct work_struct *work)
 217 {
 218         struct pcie_pme_service_data *data =
 219                         container_of(work, struct pcie_pme_service_data, work);
 220         struct pci_dev *port = data->srv->port;
 221         u32 rtsta;
 222
 223         spin_lock_irq(&data->lock);
 224
 225         for (;;) {
 226                 if (data->noirq)
 227                         break;
 228
 229                 pcie_capability_read_dword(port, PCI_EXP_RTSTA, &rtsta);
 230                 if (rtsta & PCI_EXP_RTSTA_PME) {
 231                         /*
 232                          * Clear PME status of the port.  If there are other
 233                          * pending PMEs, the status will be set again.
 234                          */
 235                         pcie_clear_root_pme_status(port);
 236
 237                         spin_unlock_irq(&data->lock);
 238                         pcie_pme_handle_request(port, rtsta & 0xffff);
 239                         spin_lock_irq(&data->lock);
 240
 241                         continue;
 242                 }
 243
 244                 /* No need to loop if there are no more PMEs pending. */
 245                 if (!(rtsta & PCI_EXP_RTSTA_PENDING))
 246                         break;
 247
 248                 spin_unlock_irq(&data->lock);
 249                 cpu_relax();
 250                 spin_lock_irq(&data->lock);
 251         }
 252
 253         if (!data->noirq)
 254                 pcie_pme_interrupt_enable(port, true);
 255
 256         spin_unlock_irq(&data->lock);
 257 }
 258
 259 /**
 260  * pcie_pme_irq - Interrupt handler for PCIe root port PME interrupt.
 261  * @irq: Interrupt vector.
 262  * @context: Interrupt context pointer.
 263  */
 264 static irqreturn_t pcie_pme_irq(int irq, void *context)
 265 {
 266         struct pci_dev *port;
 267         struct pcie_pme_service_data *data;
 268         u32 rtsta;
 269         unsigned long flags;
 270
 271         port = ((struct pcie_device *)context)->port;
 272         data = get_service_data((struct pcie_device *)context);
 273
 274         spin_lock_irqsave(&data->lock, flags);
 275         pcie_capability_read_dword(port, PCI_EXP_RTSTA, &rtsta);
 276
 277         if (!(rtsta & PCI_EXP_RTSTA_PME)) {
 278                 spin_unlock_irqrestore(&data->lock, flags);
 279                 return IRQ_NONE;
 280         }
 281
 282         pcie_pme_interrupt_enable(port, false);
 283         spin_unlock_irqrestore(&data->lock, flags);
 284
 285         /* We don't use pm_wq, because it's freezable. */
 286         schedule_work(&data->work);
 287
 288         return IRQ_HANDLED;
 289 }
 290
 291 /**
 292  * pcie_pme_set_native - Set the PME interrupt flag for given device.
 293  * @dev: PCI device to handle.
 294  * @ign: Ignored.
 295  */
 296 static int pcie_pme_set_native(struct pci_dev *dev, void *ign)
 297 {
 298         dev_info(&dev->dev, "Signaling PME through PCIe PME interrupt\n");
 299
 300         device_set_run_wake(&dev->dev, true);
 301         dev->pme_interrupt = true;
 302         return 0;
 303 }
 304
 305 /**
 306  * pcie_pme_mark_devices - Set the PME interrupt flag for devices below a port.
 307  * @port: PCIe root port or event collector to handle.
 308  *
 309  * For each device below given root port, including the port itself (or for each
 310  * root complex integrated endpoint if @port is a root complex event collector)
 311  * set the flag indicating that it can signal run-time wake-up events via PCIe
 312  * PME interrupts.
 313  */
 314 static void pcie_pme_mark_devices(struct pci_dev *port)
 315 {
 316         pcie_pme_set_native(port, NULL);
 317         if (port->subordinate) {
 318                 pci_walk_bus(port->subordinate, pcie_pme_set_native, NULL);
 319         } else {
 320                 struct pci_bus *bus = port->bus;
 321                 struct pci_dev *dev;
 322
 323                 /* Check if this is a root port event collector. */
 324                 if (pci_pcie_type(port) != PCI_EXP_TYPE_RC_EC || !bus)
 325                         return;
 326
 327                 down_read(&pci_bus_sem);
 328                 list_for_each_entry(dev, &bus->devices, bus_list)
 329                         if (pci_is_pcie(dev)
 330                             && pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END)
 331                                 pcie_pme_set_native(dev, NULL);
 332                 up_read(&pci_bus_sem);
 333         }
 334 }
 335
 336 /**
 337  * pcie_pme_probe - Initialize PCIe PME service for given root port.
 338  * @srv: PCIe service to initialize.
 339  */
 340 static int pcie_pme_probe(struct pcie_device *srv)
 341 {
 342         struct pci_dev *port;
 343         struct pcie_pme_service_data *data;
 344         int ret;
 345
 346         data = kzalloc(sizeof(*data), GFP_KERNEL);
 347         if (!data)
 348                 return -ENOMEM;
 349
 350         spin_lock_init(&data->lock);
 351         INIT_WORK(&data->work, pcie_pme_work_fn);
 352         data->srv = srv;
 353         set_service_data(srv, data);
 354
 355         port = srv->port;
 356         pcie_pme_interrupt_enable(port, false);
 357         pcie_clear_root_pme_status(port);
 358
 359         ret = request_irq(srv->irq, pcie_pme_irq, IRQF_SHARED, "PCIe PME", srv);
 360         if (ret) {
 361                 kfree(data);
 362         } else {
 363                 pcie_pme_mark_devices(port);
 364                 pcie_pme_interrupt_enable(port, true);
 365         }
 366
 367         return ret;
 368 }
 369
 370 /**
 371  * pcie_pme_suspend - Suspend PCIe PME service device.
 372  * @srv: PCIe service device to suspend.
 373  */
 374 static int pcie_pme_suspend(struct pcie_device *srv)
 375 {
 376         struct pcie_pme_service_data *data = get_service_data(srv);
 377         struct pci_dev *port = srv->port;
 378
 379         spin_lock_irq(&data->lock);
 380         pcie_pme_interrupt_enable(port, false);
 381         pcie_clear_root_pme_status(port);
 382         data->noirq = true;
 383         spin_unlock_irq(&data->lock);
 384
 385         synchronize_irq(srv->irq);
 386
 387         return 0;
 388 }
 389
 390 /**
 391  * pcie_pme_resume - Resume PCIe PME service device.
 392  * @srv - PCIe service device to resume.
 393  */
 394 static int pcie_pme_resume(struct pcie_device *srv)
 395 {
 396         struct pcie_pme_service_data *data = get_service_data(srv);
 397         struct pci_dev *port = srv->port;
 398
 399         spin_lock_irq(&data->lock);
 400         data->noirq = false;
 401         pcie_clear_root_pme_status(port);
 402         pcie_pme_interrupt_enable(port, true);
 403         spin_unlock_irq(&data->lock);
 404
 405         return 0;
 406 }
 407
 408 /**
 409  * pcie_pme_remove - Prepare PCIe PME service device for removal.
 410  * @srv - PCIe service device to remove.
 411  */
 412 static void pcie_pme_remove(struct pcie_device *srv)
 413 {
 414         pcie_pme_suspend(srv);
 415         free_irq(srv->irq, srv);
 416         kfree(get_service_data(srv));
 417 }
 418
 419 static struct pcie_port_service_driver pcie_pme_driver = {
 420         .name           = "pcie_pme",
 421         .port_type      = PCI_EXP_TYPE_ROOT_PORT,
 422         .service        = PCIE_PORT_SERVICE_PME,
 423
 424         .probe          = pcie_pme_probe,
 425         .suspend        = pcie_pme_suspend,
 426         .resume         = pcie_pme_resume,
 427         .remove         = pcie_pme_remove,
 428 };
 429
 430 /**
 431  * pcie_pme_service_init - Register the PCIe PME service driver.
 432  */
 433 static int __init pcie_pme_service_init(void)
 434 {
 435         return pcie_port_service_register(&pcie_pme_driver);
 436 }
 437
 438 module_init(pcie_pme_service_init);