drivers/pci/pcie/portdrv_core.c

   1 /*
   2  * File:        portdrv_core.c
   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/string.h>
  15 #include <linux/slab.h>
  16 #include <linux/pcieport_if.h>
  17
  18 #include "../pci.h"
  19 #include "portdrv.h"
  20
  21 /**
  22  * release_pcie_device - free PCI Express port service device structure
  23  * @dev: Port service device to release
  24  *
  25  * Invoked automatically when device is being removed in response to
  26  * device_unregister(dev).  Release all resources being claimed.
  27  */
  28 static void release_pcie_device(struct device *dev)
  29 {
  30         kfree(to_pcie_device(dev));
  31 }
  32
  33 /**
  34  * pcie_port_msix_add_entry - add entry to given array of MSI-X entries
  35  * @entries: Array of MSI-X entries
  36  * @new_entry: Index of the entry to add to the array
  37  * @nr_entries: Number of entries aleady in the array
  38  *
  39  * Return value: Position of the added entry in the array
  40  */
  41 static int pcie_port_msix_add_entry(
  42         struct msix_entry *entries, int new_entry, int nr_entries)
  43 {
  44         int j;
  45
  46         for (j = 0; j < nr_entries; j++)
  47                 if (entries[j].entry == new_entry)
  48                         return j;
  49
  50         entries[j].entry = new_entry;
  51         return j;
  52 }
  53
  54 /**
  55  * pcie_port_enable_msix - try to set up MSI-X as interrupt mode for given port
  56  * @dev: PCI Express port to handle
  57  * @vectors: Array of interrupt vectors to populate
  58  * @mask: Bitmask of port capabilities returned by get_port_device_capability()
  59  *
  60  * Return value: 0 on success, error code on failure
  61  */
  62 static int pcie_port_enable_msix(struct pci_dev *dev, int *vectors, int mask)
  63 {
  64         struct msix_entry *msix_entries;
  65         int idx[PCIE_PORT_DEVICE_MAXSERVICES];
  66         int nr_entries, status, pos, i, nvec;
  67         u16 reg16;
  68         u32 reg32;
  69
  70         nr_entries = pci_msix_table_size(dev);
  71         if (!nr_entries)
  72                 return -EINVAL;
  73         if (nr_entries > PCIE_PORT_MAX_MSIX_ENTRIES)
  74                 nr_entries = PCIE_PORT_MAX_MSIX_ENTRIES;
  75
  76         msix_entries = kzalloc(sizeof(*msix_entries) * nr_entries, GFP_KERNEL);
  77         if (!msix_entries)
  78                 return -ENOMEM;
  79
  80         /*
  81          * Allocate as many entries as the port wants, so that we can check
  82          * which of them will be useful.  Moreover, if nr_entries is correctly
  83          * equal to the number of entries this port actually uses, we'll happily
  84          * go through without any tricks.
  85          */
  86         for (i = 0; i < nr_entries; i++)
  87                 msix_entries[i].entry = i;
  88
  89         status = pci_enable_msix(dev, msix_entries, nr_entries);
  90         if (status)
  91                 goto Exit;
  92
  93         for (i = 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++)
  94                 idx[i] = -1;
  95         status = -EIO;
  96         nvec = 0;
  97
  98         if (mask & (PCIE_PORT_SERVICE_PME | PCIE_PORT_SERVICE_HP)) {
  99                 int entry;
 100
 101                 /*
 102                  * The code below follows the PCI Express Base Specification 2.0
 103                  * stating in Section 6.1.6 that "PME and Hot-Plug Event
 104                  * interrupts (when both are implemented) always share the same
 105                  * MSI or MSI-X vector, as indicated by the Interrupt Message
 106                  * Number field in the PCI Express Capabilities register", where
 107                  * according to Section 7.8.2 of the specification "For MSI-X,
 108                  * the value in this field indicates which MSI-X Table entry is
 109                  * used to generate the interrupt message."
 110                  */
 111                 pos = pci_find_capability(dev, PCI_CAP_ID_EXP);
 112                 pci_read_config_word(dev, pos + PCIE_CAPABILITIES_REG, &reg16);
 113                 entry = (reg16 >> 9) & PCIE_PORT_MSI_VECTOR_MASK;
 114                 if (entry >= nr_entries)
 115                         goto Error;
 116
 117                 i = pcie_port_msix_add_entry(msix_entries, entry, nvec);
 118                 if (i == nvec)
 119                         nvec++;
 120
 121                 idx[PCIE_PORT_SERVICE_PME_SHIFT] = i;
 122                 idx[PCIE_PORT_SERVICE_HP_SHIFT] = i;
 123         }
 124
 125         if (mask & PCIE_PORT_SERVICE_AER) {
 126                 int entry;
 127
 128                 /*
 129                  * The code below follows Section 7.10.10 of the PCI Express
 130                  * Base Specification 2.0 stating that bits 31-27 of the Root
 131                  * Error Status Register contain a value indicating which of the
 132                  * MSI/MSI-X vectors assigned to the port is going to be used
 133                  * for AER, where "For MSI-X, the value in this register
 134                  * indicates which MSI-X Table entry is used to generate the
 135                  * interrupt message."
 136                  */
 137                 pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
 138                 pci_read_config_dword(dev, pos + PCI_ERR_ROOT_STATUS, &reg32);
 139                 entry = reg32 >> 27;
 140                 if (entry >= nr_entries)
 141                         goto Error;
 142
 143                 i = pcie_port_msix_add_entry(msix_entries, entry, nvec);
 144                 if (i == nvec)
 145                         nvec++;
 146
 147                 idx[PCIE_PORT_SERVICE_AER_SHIFT] = i;
 148         }
 149
 150         /*
 151          * If nvec is equal to the allocated number of entries, we can just use
 152          * what we have.  Otherwise, the port has some extra entries not for the
 153          * services we know and we need to work around that.
 154          */
 155         if (nvec == nr_entries) {
 156                 status = 0;
 157         } else {
 158                 /* Drop the temporary MSI-X setup */
 159                 pci_disable_msix(dev);
 160
 161                 /* Now allocate the MSI-X vectors for real */
 162                 status = pci_enable_msix(dev, msix_entries, nvec);
 163                 if (status)
 164                         goto Exit;
 165         }
 166
 167         for (i = 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++)
 168                 vectors[i] = idx[i] >= 0 ? msix_entries[idx[i]].vector : -1;
 169
 170  Exit:
 171         kfree(msix_entries);
 172         return status;
 173
 174  Error:
 175         pci_disable_msix(dev);
 176         goto Exit;
 177 }
 178
 179 /**
 180  * assign_interrupt_mode - choose interrupt mode for PCI Express port services
 181  *                         (INTx, MSI-X, MSI) and set up vectors
 182  * @dev: PCI Express port to handle
 183  * @vectors: Array of interrupt vectors to populate
 184  * @mask: Bitmask of port capabilities returned by get_port_device_capability()
 185  *
 186  * Return value: Interrupt mode associated with the port
 187  */
 188 static int assign_interrupt_mode(struct pci_dev *dev, int *vectors, int mask)
 189 {
 190         int irq, interrupt_mode = PCIE_PORT_NO_IRQ;
 191         int i;
 192
 193         /* Try to use MSI-X if supported */
 194         if (!pcie_port_enable_msix(dev, vectors, mask))
 195                 return PCIE_PORT_MSIX_MODE;
 196
 197         /* We're not going to use MSI-X, so try MSI and fall back to INTx */
 198         if (!pci_enable_msi(dev))
 199                 interrupt_mode = PCIE_PORT_MSI_MODE;
 200
 201         if (interrupt_mode == PCIE_PORT_NO_IRQ && dev->pin)
 202                 interrupt_mode = PCIE_PORT_INTx_MODE;
 203
 204         irq = interrupt_mode != PCIE_PORT_NO_IRQ ? dev->irq : -1;
 205         for (i = 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++)
 206                 vectors[i] = irq;
 207
 208         vectors[PCIE_PORT_SERVICE_VC_SHIFT] = -1;
 209
 210         return interrupt_mode;
 211 }
 212
 213 /**
 214  * get_port_device_capability - discover capabilities of a PCI Express port
 215  * @dev: PCI Express port to examine
 216  *
 217  * The capabilities are read from the port's PCI Express configuration registers
 218  * as described in PCI Express Base Specification 1.0a sections 7.8.2, 7.8.9 and
 219  * 7.9 - 7.11.
 220  *
 221  * Return value: Bitmask of discovered port capabilities
 222  */
 223 static int get_port_device_capability(struct pci_dev *dev)
 224 {
 225         int services = 0, pos;
 226         u16 reg16;
 227         u32 reg32;
 228
 229         pos = pci_find_capability(dev, PCI_CAP_ID_EXP);
 230         pci_read_config_word(dev, pos + PCIE_CAPABILITIES_REG, &reg16);
 231         /* Hot-Plug Capable */
 232         if (reg16 & PORT_TO_SLOT_MASK) {
 233                 pci_read_config_dword(dev,
 234                         pos + PCIE_SLOT_CAPABILITIES_REG, &reg32);
 235                 if (reg32 & SLOT_HP_CAPABLE_MASK)
 236                         services |= PCIE_PORT_SERVICE_HP;
 237         }
 238         /* AER capable */
 239         if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR))
 240                 services |= PCIE_PORT_SERVICE_AER;
 241         /* VC support */
 242         if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_VC))
 243                 services |= PCIE_PORT_SERVICE_VC;
 244
 245         return services;
 246 }
 247
 248 /**
 249  * pcie_device_init - initialize PCI Express port service device
 250  * @dev: Port service device to initialize
 251  * @parent: PCI Express port to associate the service device with
 252  * @port_type: Type of the port
 253  * @service_type: Type of service to associate with the service device
 254  * @irq: Interrupt vector to associate with the service device
 255  */
 256 static void pcie_device_init(struct pci_dev *parent, struct pcie_device *dev,
 257         int service_type, int irq)
 258 {
 259         struct pcie_port_data *port_data = pci_get_drvdata(parent);
 260         struct device *device;
 261         int port_type = port_data->port_type;
 262
 263         dev->port = parent;
 264         dev->irq = irq;
 265         dev->service = service_type;
 266
 267         /* Initialize generic device interface */
 268         device = &dev->device;
 269         memset(device, 0, sizeof(struct device));
 270         device->bus = &pcie_port_bus_type;
 271         device->driver = NULL;
 272         dev_set_drvdata(device, NULL);
 273         device->release = release_pcie_device;  /* callback to free pcie dev */
 274         dev_set_name(device, "%s:pcie%02x",
 275                  pci_name(parent), get_descriptor_id(port_type, service_type));
 276         device->parent = &parent->dev;
 277 }
 278
 279 /**
 280  * alloc_pcie_device - allocate PCI Express port service device structure
 281  * @parent: PCI Express port to associate the service device with
 282  * @port_type: Type of the port
 283  * @service_type: Type of service to associate with the service device
 284  * @irq: Interrupt vector to associate with the service device
 285  */
 286 static struct pcie_device* alloc_pcie_device(struct pci_dev *parent,
 287         int service_type, int irq)
 288 {
 289         struct pcie_device *device;
 290
 291         device = kzalloc(sizeof(struct pcie_device), GFP_KERNEL);
 292         if (!device)
 293                 return NULL;
 294
 295         pcie_device_init(parent, device, service_type, irq);
 296         return device;
 297 }
 298
 299 /**
 300  * pcie_port_device_probe - check if device is a PCI Express port
 301  * @dev: Device to check
 302  */
 303 int pcie_port_device_probe(struct pci_dev *dev)
 304 {
 305         int pos, type;
 306         u16 reg;
 307
 308         if (!(pos = pci_find_capability(dev, PCI_CAP_ID_EXP)))
 309                 return -ENODEV;
 310
 311         pci_read_config_word(dev, pos + PCIE_CAPABILITIES_REG, &reg);
 312         type = (reg >> 4) & PORT_TYPE_MASK;
 313         if (    type == PCIE_RC_PORT || type == PCIE_SW_UPSTREAM_PORT ||
 314                 type == PCIE_SW_DOWNSTREAM_PORT )
 315                 return 0;
 316
 317         return -ENODEV;
 318 }
 319
 320 /**
 321  * pcie_port_device_register - register PCI Express port
 322  * @dev: PCI Express port to register
 323  *
 324  * Allocate the port extension structure and register services associated with
 325  * the port.
 326  */
 327 int pcie_port_device_register(struct pci_dev *dev)
 328 {
 329         struct pcie_port_data *port_data;
 330         int status, capabilities, irq_mode, i, nr_serv;
 331         int vectors[PCIE_PORT_DEVICE_MAXSERVICES];
 332         u16 reg16;
 333
 334         port_data = kzalloc(sizeof(*port_data), GFP_KERNEL);
 335         if (!port_data)
 336                 return -ENOMEM;
 337         pci_set_drvdata(dev, port_data);
 338
 339         /* Get port type */
 340         pci_read_config_word(dev,
 341                 pci_find_capability(dev, PCI_CAP_ID_EXP) +
 342                 PCIE_CAPABILITIES_REG, &reg16);
 343         port_data->port_type = (reg16 >> 4) & PORT_TYPE_MASK;
 344
 345         capabilities = get_port_device_capability(dev);
 346         /* Root ports are capable of generating PME too */
 347         if (port_data->port_type == PCIE_RC_PORT)
 348                 capabilities |= PCIE_PORT_SERVICE_PME;
 349
 350         irq_mode = assign_interrupt_mode(dev, vectors, capabilities);
 351         if (irq_mode == PCIE_PORT_NO_IRQ) {
 352                 /*
 353                  * Don't use service devices that require interrupts if there is
 354                  * no way to generate them.
 355                  */
 356                 if (!(capabilities & PCIE_PORT_SERVICE_VC)) {
 357                         status = -ENODEV;
 358                         goto Error;
 359                 }
 360                 capabilities = PCIE_PORT_SERVICE_VC;
 361         }
 362         port_data->port_irq_mode = irq_mode;
 363
 364         status = pci_enable_device(dev);
 365         if (status)
 366                 goto Error;
 367         pci_set_master(dev);
 368
 369         /* Allocate child services if any */
 370         for (i = 0, nr_serv = 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++) {
 371                 struct pcie_device *child;
 372                 int service = 1 << i;
 373
 374                 if (!(capabilities & service))
 375                         continue;
 376
 377                 child = alloc_pcie_device(dev, service, vectors[i]);
 378                 if (!child)
 379                         continue;
 380
 381                 status = device_register(&child->device);
 382                 if (status) {
 383                         kfree(child);
 384                         continue;
 385                 }
 386
 387                 get_device(&child->device);
 388                 nr_serv++;
 389         }
 390         if (!nr_serv) {
 391                 pci_disable_device(dev);
 392                 status = -ENODEV;
 393                 goto Error;
 394         }
 395
 396         return 0;
 397
 398  Error:
 399         kfree(port_data);
 400         return status;
 401 }
 402
 403 #ifdef CONFIG_PM
 404 static int suspend_iter(struct device *dev, void *data)
 405 {
 406         struct pcie_port_service_driver *service_driver;
 407
 408         if ((dev->bus == &pcie_port_bus_type) &&
 409             (dev->driver)) {
 410                 service_driver = to_service_driver(dev->driver);
 411                 if (service_driver->suspend)
 412                         service_driver->suspend(to_pcie_device(dev));
 413         }
 414         return 0;
 415 }
 416
 417 /**
 418  * pcie_port_device_suspend - suspend port services associated with a PCIe port
 419  * @dev: PCI Express port to handle
 420  */
 421 int pcie_port_device_suspend(struct device *dev)
 422 {
 423         return device_for_each_child(dev, NULL, suspend_iter);
 424 }
 425
 426 static int resume_iter(struct device *dev, void *data)
 427 {
 428         struct pcie_port_service_driver *service_driver;
 429
 430         if ((dev->bus == &pcie_port_bus_type) &&
 431             (dev->driver)) {
 432                 service_driver = to_service_driver(dev->driver);
 433                 if (service_driver->resume)
 434                         service_driver->resume(to_pcie_device(dev));
 435         }
 436         return 0;
 437 }
 438
 439 /**
 440  * pcie_port_device_suspend - resume port services associated with a PCIe port
 441  * @dev: PCI Express port to handle
 442  */
 443 int pcie_port_device_resume(struct device *dev)
 444 {
 445         return device_for_each_child(dev, NULL, resume_iter);
 446 }
 447 #endif /* PM */
 448
 449 static int remove_iter(struct device *dev, void *data)
 450 {
 451         if (dev->bus == &pcie_port_bus_type) {
 452                 put_device(dev);
 453                 device_unregister(dev);
 454         }
 455         return 0;
 456 }
 457
 458 /**
 459  * pcie_port_device_remove - unregister PCI Express port service devices
 460  * @dev: PCI Express port the service devices to unregister are associated with
 461  *
 462  * Remove PCI Express port service devices associated with given port and
 463  * disable MSI-X or MSI for the port.
 464  */
 465 void pcie_port_device_remove(struct pci_dev *dev)
 466 {
 467         struct pcie_port_data *port_data = pci_get_drvdata(dev);
 468
 469         device_for_each_child(&dev->dev, NULL, remove_iter);
 470         pci_disable_device(dev);
 471
 472         switch (port_data->port_irq_mode) {
 473         case PCIE_PORT_MSIX_MODE:
 474                 pci_disable_msix(dev);
 475                 break;
 476         case PCIE_PORT_MSI_MODE:
 477                 pci_disable_msi(dev);
 478                 break;
 479         }
 480
 481         kfree(port_data);
 482 }
 483
 484 /**
 485  * pcie_port_probe_service - probe driver for given PCI Express port service
 486  * @dev: PCI Express port service device to probe against
 487  *
 488  * If PCI Express port service driver is registered with
 489  * pcie_port_service_register(), this function will be called by the driver core
 490  * whenever match is found between the driver and a port service device.
 491  */
 492 static int pcie_port_probe_service(struct device *dev)
 493 {
 494         struct pcie_device *pciedev;
 495         struct pcie_port_service_driver *driver;
 496         int status;
 497
 498         if (!dev || !dev->driver)
 499                 return -ENODEV;
 500
 501         driver = to_service_driver(dev->driver);
 502         if (!driver || !driver->probe)
 503                 return -ENODEV;
 504
 505         pciedev = to_pcie_device(dev);
 506         status = driver->probe(pciedev);
 507         if (!status) {
 508                 dev_printk(KERN_DEBUG, dev, "service driver %s loaded\n",
 509                         driver->name);
 510                 get_device(dev);
 511         }
 512         return status;
 513 }
 514
 515 /**
 516  * pcie_port_remove_service - detach driver from given PCI Express port service
 517  * @dev: PCI Express port service device to handle
 518  *
 519  * If PCI Express port service driver is registered with
 520  * pcie_port_service_register(), this function will be called by the driver core
 521  * when device_unregister() is called for the port service device associated
 522  * with the driver.
 523  */
 524 static int pcie_port_remove_service(struct device *dev)
 525 {
 526         struct pcie_device *pciedev;
 527         struct pcie_port_service_driver *driver;
 528
 529         if (!dev || !dev->driver)
 530                 return 0;
 531
 532         pciedev = to_pcie_device(dev);
 533         driver = to_service_driver(dev->driver);
 534         if (driver && driver->remove) {
 535                 dev_printk(KERN_DEBUG, dev, "unloading service driver %s\n",
 536                         driver->name);
 537                 driver->remove(pciedev);
 538                 put_device(dev);
 539         }
 540         return 0;
 541 }
 542
 543 /**
 544  * pcie_port_shutdown_service - shut down 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_shutdown() is called for the port service device associated
 550  * with the driver.
 551  */
 552 static void pcie_port_shutdown_service(struct device *dev) {}
 553
 554 /**
 555  * pcie_port_service_register - register PCI Express port service driver
 556  * @new: PCI Express port service driver to register
 557  */
 558 int pcie_port_service_register(struct pcie_port_service_driver *new)
 559 {
 560         new->driver.name = (char *)new->name;
 561         new->driver.bus = &pcie_port_bus_type;
 562         new->driver.probe = pcie_port_probe_service;
 563         new->driver.remove = pcie_port_remove_service;
 564         new->driver.shutdown = pcie_port_shutdown_service;
 565
 566         return driver_register(&new->driver);
 567 }
 568
 569 /**
 570  * pcie_port_service_unregister - unregister PCI Express port service driver
 571  * @drv: PCI Express port service driver to unregister
 572  */
 573 void pcie_port_service_unregister(struct pcie_port_service_driver *drv)
 574 {
 575         driver_unregister(&drv->driver);
 576 }
 577
 578 EXPORT_SYMBOL(pcie_port_service_register);
 579 EXPORT_SYMBOL(pcie_port_service_unregister);