root/drivers/pci/pcie/portdrv_core.c

DEFINITIONS

1. release_pcie_device
2. pcie_message_numbers
3. pcie_port_enable_irq_vec
4. pcie_init_service_irqs
5. get_port_device_capability
6. pcie_device_init
7. pcie_port_device_register
8. pm_iter
9. pcie_port_device_suspend
10. pcie_port_device_resume_noirq
11. pcie_port_device_resume
12. pcie_port_device_runtime_suspend
13. pcie_port_device_runtime_resume
14. remove_iter
15. find_service_iter
16. pcie_port_find_service
17. pcie_port_find_device
18. pcie_port_device_remove
19. pcie_port_probe_service
20. pcie_port_remove_service
21. pcie_port_shutdown_service
22. pcie_port_service_register
23. pcie_port_service_unregister

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Purpose:     PCI Express Port Bus Driver's Core Functions
   4  *
   5  * Copyright (C) 2004 Intel
   6  * Copyright (C) Tom Long Nguyen (tom.l.nguyen@intel.com)
   7  */
   8 
   9 #include <linux/module.h>
  10 #include <linux/pci.h>
  11 #include <linux/kernel.h>
  12 #include <linux/errno.h>
  13 #include <linux/pm.h>
  14 #include <linux/pm_runtime.h>
  15 #include <linux/string.h>
  16 #include <linux/slab.h>
  17 #include <linux/aer.h>
  18 
  19 #include "../pci.h"
  20 #include "portdrv.h"
  21 
  22 struct portdrv_service_data {
  23         struct pcie_port_service_driver *drv;
  24         struct device *dev;
  25         u32 service;
  26 };
  27 
  28 /**
  29  * release_pcie_device - free PCI Express port service device structure
  30  * @dev: Port service device to release
  31  *
  32  * Invoked automatically when device is being removed in response to
  33  * device_unregister(dev).  Release all resources being claimed.
  34  */
  35 static void release_pcie_device(struct device *dev)
  36 {
  37         kfree(to_pcie_device(dev));
  38 }
  39 
  40 /*
  41  * Fill in *pme, *aer, *dpc with the relevant Interrupt Message Numbers if
  42  * services are enabled in "mask".  Return the number of MSI/MSI-X vectors
  43  * required to accommodate the largest Message Number.
  44  */
  45 static int pcie_message_numbers(struct pci_dev *dev, int mask,
  46                                 u32 *pme, u32 *aer, u32 *dpc)
  47 {
  48         u32 nvec = 0, pos;
  49         u16 reg16;
  50 
  51         /*
  52          * The Interrupt Message Number indicates which vector is used, i.e.,
  53          * the MSI-X table entry or the MSI offset between the base Message
  54          * Data and the generated interrupt message.  See PCIe r3.1, sec
  55          * 7.8.2, 7.10.10, 7.31.2.
  56          */
  57 
  58         if (mask & (PCIE_PORT_SERVICE_PME | PCIE_PORT_SERVICE_HP |
  59                     PCIE_PORT_SERVICE_BWNOTIF)) {
  60                 pcie_capability_read_word(dev, PCI_EXP_FLAGS, &reg16);
  61                 *pme = (reg16 & PCI_EXP_FLAGS_IRQ) >> 9;
  62                 nvec = *pme + 1;
  63         }
  64 
  65 #ifdef CONFIG_PCIEAER
  66         if (mask & PCIE_PORT_SERVICE_AER) {
  67                 u32 reg32;
  68 
  69                 pos = dev->aer_cap;
  70                 if (pos) {
  71                         pci_read_config_dword(dev, pos + PCI_ERR_ROOT_STATUS,
  72                                               &reg32);
  73                         *aer = (reg32 & PCI_ERR_ROOT_AER_IRQ) >> 27;
  74                         nvec = max(nvec, *aer + 1);
  75                 }
  76         }
  77 #endif
  78 
  79         if (mask & PCIE_PORT_SERVICE_DPC) {
  80                 pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC);
  81                 if (pos) {
  82                         pci_read_config_word(dev, pos + PCI_EXP_DPC_CAP,
  83                                              &reg16);
  84                         *dpc = reg16 & PCI_EXP_DPC_IRQ;
  85                         nvec = max(nvec, *dpc + 1);
  86                 }
  87         }
  88 
  89         return nvec;
  90 }
  91 
  92 /**
  93  * pcie_port_enable_irq_vec - try to set up MSI-X or MSI as interrupt mode
  94  * for given port
  95  * @dev: PCI Express port to handle
  96  * @irqs: Array of interrupt vectors to populate
  97  * @mask: Bitmask of port capabilities returned by get_port_device_capability()
  98  *
  99  * Return value: 0 on success, error code on failure
 100  */
 101 static int pcie_port_enable_irq_vec(struct pci_dev *dev, int *irqs, int mask)
 102 {
 103         int nr_entries, nvec, pcie_irq;
 104         u32 pme = 0, aer = 0, dpc = 0;
 105 
 106         /* Allocate the maximum possible number of MSI/MSI-X vectors */
 107         nr_entries = pci_alloc_irq_vectors(dev, 1, PCIE_PORT_MAX_MSI_ENTRIES,
 108                         PCI_IRQ_MSIX | PCI_IRQ_MSI);
 109         if (nr_entries < 0)
 110                 return nr_entries;
 111 
 112         /* See how many and which Interrupt Message Numbers we actually use */
 113         nvec = pcie_message_numbers(dev, mask, &pme, &aer, &dpc);
 114         if (nvec > nr_entries) {
 115                 pci_free_irq_vectors(dev);
 116                 return -EIO;
 117         }
 118 
 119         /*
 120          * If we allocated more than we need, free them and reallocate fewer.
 121          *
 122          * Reallocating may change the specific vectors we get, so
 123          * pci_irq_vector() must be done *after* the reallocation.
 124          *
 125          * If we're using MSI, hardware is *allowed* to change the Interrupt
 126          * Message Numbers when we free and reallocate the vectors, but we
 127          * assume it won't because we allocate enough vectors for the
 128          * biggest Message Number we found.
 129          */
 130         if (nvec != nr_entries) {
 131                 pci_free_irq_vectors(dev);
 132 
 133                 nr_entries = pci_alloc_irq_vectors(dev, nvec, nvec,
 134                                 PCI_IRQ_MSIX | PCI_IRQ_MSI);
 135                 if (nr_entries < 0)
 136                         return nr_entries;
 137         }
 138 
 139         /* PME, hotplug and bandwidth notification share an MSI/MSI-X vector */
 140         if (mask & (PCIE_PORT_SERVICE_PME | PCIE_PORT_SERVICE_HP |
 141                     PCIE_PORT_SERVICE_BWNOTIF)) {
 142                 pcie_irq = pci_irq_vector(dev, pme);
 143                 irqs[PCIE_PORT_SERVICE_PME_SHIFT] = pcie_irq;
 144                 irqs[PCIE_PORT_SERVICE_HP_SHIFT] = pcie_irq;
 145                 irqs[PCIE_PORT_SERVICE_BWNOTIF_SHIFT] = pcie_irq;
 146         }
 147 
 148         if (mask & PCIE_PORT_SERVICE_AER)
 149                 irqs[PCIE_PORT_SERVICE_AER_SHIFT] = pci_irq_vector(dev, aer);
 150 
 151         if (mask & PCIE_PORT_SERVICE_DPC)
 152                 irqs[PCIE_PORT_SERVICE_DPC_SHIFT] = pci_irq_vector(dev, dpc);
 153 
 154         return 0;
 155 }
 156 
 157 /**
 158  * pcie_init_service_irqs - initialize irqs for PCI Express port services
 159  * @dev: PCI Express port to handle
 160  * @irqs: Array of irqs to populate
 161  * @mask: Bitmask of port capabilities returned by get_port_device_capability()
 162  *
 163  * Return value: Interrupt mode associated with the port
 164  */
 165 static int pcie_init_service_irqs(struct pci_dev *dev, int *irqs, int mask)
 166 {
 167         int ret, i;
 168 
 169         for (i = 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++)
 170                 irqs[i] = -1;
 171 
 172         /*
 173          * If we support PME but can't use MSI/MSI-X for it, we have to
 174          * fall back to INTx or other interrupts, e.g., a system shared
 175          * interrupt.
 176          */
 177         if ((mask & PCIE_PORT_SERVICE_PME) && pcie_pme_no_msi())
 178                 goto legacy_irq;
 179 
 180         /* Try to use MSI-X or MSI if supported */
 181         if (pcie_port_enable_irq_vec(dev, irqs, mask) == 0)
 182                 return 0;
 183 
 184 legacy_irq:
 185         /* fall back to legacy IRQ */
 186         ret = pci_alloc_irq_vectors(dev, 1, 1, PCI_IRQ_LEGACY);
 187         if (ret < 0)
 188                 return -ENODEV;
 189 
 190         for (i = 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++)
 191                 irqs[i] = pci_irq_vector(dev, 0);
 192 
 193         return 0;
 194 }
 195 
 196 /**
 197  * get_port_device_capability - discover capabilities of a PCI Express port
 198  * @dev: PCI Express port to examine
 199  *
 200  * The capabilities are read from the port's PCI Express configuration registers
 201  * as described in PCI Express Base Specification 1.0a sections 7.8.2, 7.8.9 and
 202  * 7.9 - 7.11.
 203  *
 204  * Return value: Bitmask of discovered port capabilities
 205  */
 206 static int get_port_device_capability(struct pci_dev *dev)
 207 {
 208         struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
 209         int services = 0;
 210 
 211         if (dev->is_hotplug_bridge &&
 212             (pcie_ports_native || host->native_pcie_hotplug)) {
 213                 services |= PCIE_PORT_SERVICE_HP;
 214 
 215                 /*
 216                  * Disable hot-plug interrupts in case they have been enabled
 217                  * by the BIOS and the hot-plug service driver is not loaded.
 218                  */
 219                 pcie_capability_clear_word(dev, PCI_EXP_SLTCTL,
 220                           PCI_EXP_SLTCTL_CCIE | PCI_EXP_SLTCTL_HPIE);
 221         }
 222 
 223 #ifdef CONFIG_PCIEAER
 224         if (dev->aer_cap && pci_aer_available() &&
 225             (pcie_ports_native || host->native_aer)) {
 226                 services |= PCIE_PORT_SERVICE_AER;
 227 
 228                 /*
 229                  * Disable AER on this port in case it's been enabled by the
 230                  * BIOS (the AER service driver will enable it when necessary).
 231                  */
 232                 pci_disable_pcie_error_reporting(dev);
 233         }
 234 #endif
 235 
 236         /*
 237          * Root ports are capable of generating PME too.  Root Complex
 238          * Event Collectors can also generate PMEs, but we don't handle
 239          * those yet.
 240          */
 241         if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT &&
 242             (pcie_ports_native || host->native_pme)) {
 243                 services |= PCIE_PORT_SERVICE_PME;
 244 
 245                 /*
 246                  * Disable PME interrupt on this port in case it's been enabled
 247                  * by the BIOS (the PME service driver will enable it when
 248                  * necessary).
 249                  */
 250                 pcie_pme_interrupt_enable(dev, false);
 251         }
 252 
 253         if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC) &&
 254             pci_aer_available() && services & PCIE_PORT_SERVICE_AER)
 255                 services |= PCIE_PORT_SERVICE_DPC;
 256 
 257         if (pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM ||
 258             pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT)
 259                 services |= PCIE_PORT_SERVICE_BWNOTIF;
 260 
 261         return services;
 262 }
 263 
 264 /**
 265  * pcie_device_init - allocate and initialize PCI Express port service device
 266  * @pdev: PCI Express port to associate the service device with
 267  * @service: Type of service to associate with the service device
 268  * @irq: Interrupt vector to associate with the service device
 269  */
 270 static int pcie_device_init(struct pci_dev *pdev, int service, int irq)
 271 {
 272         int retval;
 273         struct pcie_device *pcie;
 274         struct device *device;
 275 
 276         pcie = kzalloc(sizeof(*pcie), GFP_KERNEL);
 277         if (!pcie)
 278                 return -ENOMEM;
 279         pcie->port = pdev;
 280         pcie->irq = irq;
 281         pcie->service = service;
 282 
 283         /* Initialize generic device interface */
 284         device = &pcie->device;
 285         device->bus = &pcie_port_bus_type;
 286         device->release = release_pcie_device;  /* callback to free pcie dev */
 287         dev_set_name(device, "%s:pcie%03x",
 288                      pci_name(pdev),
 289                      get_descriptor_id(pci_pcie_type(pdev), service));
 290         device->parent = &pdev->dev;
 291         device_enable_async_suspend(device);
 292 
 293         retval = device_register(device);
 294         if (retval) {
 295                 put_device(device);
 296                 return retval;
 297         }
 298 
 299         pm_runtime_no_callbacks(device);
 300 
 301         return 0;
 302 }
 303 
 304 /**
 305  * pcie_port_device_register - register PCI Express port
 306  * @dev: PCI Express port to register
 307  *
 308  * Allocate the port extension structure and register services associated with
 309  * the port.
 310  */
 311 int pcie_port_device_register(struct pci_dev *dev)
 312 {
 313         int status, capabilities, i, nr_service;
 314         int irqs[PCIE_PORT_DEVICE_MAXSERVICES];
 315 
 316         /* Enable PCI Express port device */
 317         status = pci_enable_device(dev);
 318         if (status)
 319                 return status;
 320 
 321         /* Get and check PCI Express port services */
 322         capabilities = get_port_device_capability(dev);
 323         if (!capabilities)
 324                 return 0;
 325 
 326         pci_set_master(dev);
 327         /*
 328          * Initialize service irqs. Don't use service devices that
 329          * require interrupts if there is no way to generate them.
 330          * However, some drivers may have a polling mode (e.g. pciehp_poll_mode)
 331          * that can be used in the absence of irqs.  Allow them to determine
 332          * if that is to be used.
 333          */
 334         status = pcie_init_service_irqs(dev, irqs, capabilities);
 335         if (status) {
 336                 capabilities &= PCIE_PORT_SERVICE_HP;
 337                 if (!capabilities)
 338                         goto error_disable;
 339         }
 340 
 341         /* Allocate child services if any */
 342         status = -ENODEV;
 343         nr_service = 0;
 344         for (i = 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++) {
 345                 int service = 1 << i;
 346                 if (!(capabilities & service))
 347                         continue;
 348                 if (!pcie_device_init(dev, service, irqs[i]))
 349                         nr_service++;
 350         }
 351         if (!nr_service)
 352                 goto error_cleanup_irqs;
 353 
 354         return 0;
 355 
 356 error_cleanup_irqs:
 357         pci_free_irq_vectors(dev);
 358 error_disable:
 359         pci_disable_device(dev);
 360         return status;
 361 }
 362 
 363 #ifdef CONFIG_PM
 364 typedef int (*pcie_pm_callback_t)(struct pcie_device *);
 365 
 366 static int pm_iter(struct device *dev, void *data)
 367 {
 368         struct pcie_port_service_driver *service_driver;
 369         size_t offset = *(size_t *)data;
 370         pcie_pm_callback_t cb;
 371 
 372         if ((dev->bus == &pcie_port_bus_type) && dev->driver) {
 373                 service_driver = to_service_driver(dev->driver);
 374                 cb = *(pcie_pm_callback_t *)((void *)service_driver + offset);
 375                 if (cb)
 376                         return cb(to_pcie_device(dev));
 377         }
 378         return 0;
 379 }
 380 
 381 /**
 382  * pcie_port_device_suspend - suspend port services associated with a PCIe port
 383  * @dev: PCI Express port to handle
 384  */
 385 int pcie_port_device_suspend(struct device *dev)
 386 {
 387         size_t off = offsetof(struct pcie_port_service_driver, suspend);
 388         return device_for_each_child(dev, &off, pm_iter);
 389 }
 390 
 391 int pcie_port_device_resume_noirq(struct device *dev)
 392 {
 393         size_t off = offsetof(struct pcie_port_service_driver, resume_noirq);
 394         return device_for_each_child(dev, &off, pm_iter);
 395 }
 396 
 397 /**
 398  * pcie_port_device_resume - resume port services associated with a PCIe port
 399  * @dev: PCI Express port to handle
 400  */
 401 int pcie_port_device_resume(struct device *dev)
 402 {
 403         size_t off = offsetof(struct pcie_port_service_driver, resume);
 404         return device_for_each_child(dev, &off, pm_iter);
 405 }
 406 
 407 /**
 408  * pcie_port_device_runtime_suspend - runtime suspend port services
 409  * @dev: PCI Express port to handle
 410  */
 411 int pcie_port_device_runtime_suspend(struct device *dev)
 412 {
 413         size_t off = offsetof(struct pcie_port_service_driver, runtime_suspend);
 414         return device_for_each_child(dev, &off, pm_iter);
 415 }
 416 
 417 /**
 418  * pcie_port_device_runtime_resume - runtime resume port services
 419  * @dev: PCI Express port to handle
 420  */
 421 int pcie_port_device_runtime_resume(struct device *dev)
 422 {
 423         size_t off = offsetof(struct pcie_port_service_driver, runtime_resume);
 424         return device_for_each_child(dev, &off, pm_iter);
 425 }
 426 #endif /* PM */
 427 
 428 static int remove_iter(struct device *dev, void *data)
 429 {
 430         if (dev->bus == &pcie_port_bus_type)
 431                 device_unregister(dev);
 432         return 0;
 433 }
 434 
 435 static int find_service_iter(struct device *device, void *data)
 436 {
 437         struct pcie_port_service_driver *service_driver;
 438         struct portdrv_service_data *pdrvs;
 439         u32 service;
 440 
 441         pdrvs = (struct portdrv_service_data *) data;
 442         service = pdrvs->service;
 443 
 444         if (device->bus == &pcie_port_bus_type && device->driver) {
 445                 service_driver = to_service_driver(device->driver);
 446                 if (service_driver->service == service) {
 447                         pdrvs->drv = service_driver;
 448                         pdrvs->dev = device;
 449                         return 1;
 450                 }
 451         }
 452 
 453         return 0;
 454 }
 455 
 456 /**
 457  * pcie_port_find_service - find the service driver
 458  * @dev: PCI Express port the service is associated with
 459  * @service: Service to find
 460  *
 461  * Find PCI Express port service driver associated with given service
 462  */
 463 struct pcie_port_service_driver *pcie_port_find_service(struct pci_dev *dev,
 464                                                         u32 service)
 465 {
 466         struct pcie_port_service_driver *drv;
 467         struct portdrv_service_data pdrvs;
 468 
 469         pdrvs.drv = NULL;
 470         pdrvs.service = service;
 471         device_for_each_child(&dev->dev, &pdrvs, find_service_iter);
 472 
 473         drv = pdrvs.drv;
 474         return drv;
 475 }
 476 
 477 /**
 478  * pcie_port_find_device - find the struct device
 479  * @dev: PCI Express port the service is associated with
 480  * @service: For the service to find
 481  *
 482  * Find the struct device associated with given service on a pci_dev
 483  */
 484 struct device *pcie_port_find_device(struct pci_dev *dev,
 485                                       u32 service)
 486 {
 487         struct device *device;
 488         struct portdrv_service_data pdrvs;
 489 
 490         pdrvs.dev = NULL;
 491         pdrvs.service = service;
 492         device_for_each_child(&dev->dev, &pdrvs, find_service_iter);
 493 
 494         device = pdrvs.dev;
 495         return device;
 496 }
 497 EXPORT_SYMBOL_GPL(pcie_port_find_device);
 498 
 499 /**
 500  * pcie_port_device_remove - unregister PCI Express port service devices
 501  * @dev: PCI Express port the service devices to unregister are associated with
 502  *
 503  * Remove PCI Express port service devices associated with given port and
 504  * disable MSI-X or MSI for the port.
 505  */
 506 void pcie_port_device_remove(struct pci_dev *dev)
 507 {
 508         device_for_each_child(&dev->dev, NULL, remove_iter);
 509         pci_free_irq_vectors(dev);
 510         pci_disable_device(dev);
 511 }
 512 
 513 /**
 514  * pcie_port_probe_service - probe driver for given PCI Express port service
 515  * @dev: PCI Express port service device to probe against
 516  *
 517  * If PCI Express port service driver is registered with
 518  * pcie_port_service_register(), this function will be called by the driver core
 519  * whenever match is found between the driver and a port service device.
 520  */
 521 static int pcie_port_probe_service(struct device *dev)
 522 {
 523         struct pcie_device *pciedev;
 524         struct pcie_port_service_driver *driver;
 525         int status;
 526 
 527         if (!dev || !dev->driver)
 528                 return -ENODEV;
 529 
 530         driver = to_service_driver(dev->driver);
 531         if (!driver || !driver->probe)
 532                 return -ENODEV;
 533 
 534         pciedev = to_pcie_device(dev);
 535         status = driver->probe(pciedev);
 536         if (status)
 537                 return status;
 538 
 539         get_device(dev);
 540         return 0;
 541 }
 542 
 543 /**
 544  * pcie_port_remove_service - detach driver from given PCI Express port service
 545  * @dev: PCI Express port service device to handle
 546  *
 547  * If PCI Express port service driver is registered with
 548  * pcie_port_service_register(), this function will be called by the driver core
 549  * when device_unregister() is called for the port service device associated
 550  * with the driver.
 551  */
 552 static int pcie_port_remove_service(struct device *dev)
 553 {
 554         struct pcie_device *pciedev;
 555         struct pcie_port_service_driver *driver;
 556 
 557         if (!dev || !dev->driver)
 558                 return 0;
 559 
 560         pciedev = to_pcie_device(dev);
 561         driver = to_service_driver(dev->driver);
 562         if (driver && driver->remove) {
 563                 driver->remove(pciedev);
 564                 put_device(dev);
 565         }
 566         return 0;
 567 }
 568 
 569 /**
 570  * pcie_port_shutdown_service - shut down given PCI Express port service
 571  * @dev: PCI Express port service device to handle
 572  *
 573  * If PCI Express port service driver is registered with
 574  * pcie_port_service_register(), this function will be called by the driver core
 575  * when device_shutdown() is called for the port service device associated
 576  * with the driver.
 577  */
 578 static void pcie_port_shutdown_service(struct device *dev) {}
 579 
 580 /**
 581  * pcie_port_service_register - register PCI Express port service driver
 582  * @new: PCI Express port service driver to register
 583  */
 584 int pcie_port_service_register(struct pcie_port_service_driver *new)
 585 {
 586         if (pcie_ports_disabled)
 587                 return -ENODEV;
 588 
 589         new->driver.name = new->name;
 590         new->driver.bus = &pcie_port_bus_type;
 591         new->driver.probe = pcie_port_probe_service;
 592         new->driver.remove = pcie_port_remove_service;
 593         new->driver.shutdown = pcie_port_shutdown_service;
 594 
 595         return driver_register(&new->driver);
 596 }
 597 EXPORT_SYMBOL(pcie_port_service_register);
 598 
 599 /**
 600  * pcie_port_service_unregister - unregister PCI Express port service driver
 601  * @drv: PCI Express port service driver to unregister
 602  */
 603 void pcie_port_service_unregister(struct pcie_port_service_driver *drv)
 604 {
 605         driver_unregister(&drv->driver);
 606 }
 607 EXPORT_SYMBOL(pcie_port_service_unregister);