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_pcie_cap(dev);
 112                 pci_read_config_word(dev, pos + PCI_EXP_FLAGS, &reg16);
 113                 entry = (reg16 & PCI_EXP_FLAGS_IRQ) >> 9;
 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  * init_service_irqs - initialize irqs for PCI Express port services
 181  * @dev: PCI Express port to handle
 182  * @irqs: Array of irqs to populate
 183  * @mask: Bitmask of port capabilities returned by get_port_device_capability()
 184  *
 185  * Return value: Interrupt mode associated with the port
 186  */
 187 static int init_service_irqs(struct pci_dev *dev, int *irqs, int mask)
 188 {
 189         int i, irq;
 190
 191         /* Try to use MSI-X if supported */
 192         if (!pcie_port_enable_msix(dev, irqs, mask))
 193                 return 0;
 194         /* We're not going to use MSI-X, so try MSI and fall back to INTx */
 195         irq = -1;
 196         if (!pci_enable_msi(dev) || dev->pin)
 197                 irq = dev->irq;
 198
 199         for (i = 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++)
 200                 irqs[i] = irq;
 201         irqs[PCIE_PORT_SERVICE_VC_SHIFT] = -1;
 202
 203         if (irq < 0)
 204                 return -ENODEV;
 205         return 0;
 206 }
 207
 208 static void cleanup_service_irqs(struct pci_dev *dev)
 209 {
 210         if (dev->msix_enabled)
 211                 pci_disable_msix(dev);
 212         else if (dev->msi_enabled)
 213                 pci_disable_msi(dev);
 214 }
 215
 216 /**
 217  * get_port_device_capability - discover capabilities of a PCI Express port
 218  * @dev: PCI Express port to examine
 219  *
 220  * The capabilities are read from the port's PCI Express configuration registers
 221  * as described in PCI Express Base Specification 1.0a sections 7.8.2, 7.8.9 and
 222  * 7.9 - 7.11.
 223  *
 224  * Return value: Bitmask of discovered port capabilities
 225  */
 226 static int get_port_device_capability(struct pci_dev *dev)
 227 {
 228         int services = 0, pos;
 229         u16 reg16;
 230         u32 reg32;
 231
 232         pos = pci_pcie_cap(dev);
 233         pci_read_config_word(dev, pos + PCI_EXP_FLAGS, &reg16);
 234         /* Hot-Plug Capable */
 235         if (reg16 & PCI_EXP_FLAGS_SLOT) {
 236                 pci_read_config_dword(dev, pos + PCI_EXP_SLTCAP, &reg32);
 237                 if (reg32 & PCI_EXP_SLTCAP_HPC)
 238                         services |= PCIE_PORT_SERVICE_HP;
 239         }
 240         /* AER capable */
 241         if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR))
 242                 services |= PCIE_PORT_SERVICE_AER;
 243         /* VC support */
 244         if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_VC))
 245                 services |= PCIE_PORT_SERVICE_VC;
 246         /* Root ports are capable of generating PME too */
 247         if (dev->pcie_type == PCI_EXP_TYPE_ROOT_PORT)
 248                 services |= PCIE_PORT_SERVICE_PME;
 249
 250         return services;
 251 }
 252
 253 /**
 254  * pcie_device_init - allocate and initialize PCI Express port service device
 255  * @pdev: PCI Express port to associate the service device with
 256  * @service: Type of service to associate with the service device
 257  * @irq: Interrupt vector to associate with the service device
 258  */
 259 static int pcie_device_init(struct pci_dev *pdev, int service, int irq)
 260 {
 261         int retval;
 262         struct pcie_device *pcie;
 263         struct device *device;
 264
 265         pcie = kzalloc(sizeof(*pcie), GFP_KERNEL);
 266         if (!pcie)
 267                 return -ENOMEM;
 268         pcie->port = pdev;
 269         pcie->irq = irq;
 270         pcie->service = service;
 271
 272         /* Initialize generic device interface */
 273         device = &pcie->device;
 274         device->bus = &pcie_port_bus_type;
 275         device->release = release_pcie_device;  /* callback to free pcie dev */
 276         dev_set_name(device, "%s:pcie%02x",
 277                      pci_name(pdev),
 278                      get_descriptor_id(pdev->pcie_type, service));
 279         device->parent = &pdev->dev;
 280
 281         retval = device_register(device);
 282         if (retval)
 283                 kfree(pcie);
 284         else
 285                 get_device(device);
 286         return retval;
 287 }
 288
 289 /**
 290  * pcie_port_device_register - register PCI Express port
 291  * @dev: PCI Express port to register
 292  *
 293  * Allocate the port extension structure and register services associated with
 294  * the port.
 295  */
 296 int pcie_port_device_register(struct pci_dev *dev)
 297 {
 298         int status, capabilities, i, nr_service;
 299         int irqs[PCIE_PORT_DEVICE_MAXSERVICES];
 300
 301         /* Get and check PCI Express port services */
 302         capabilities = get_port_device_capability(dev);
 303         if (!capabilities)
 304                 return -ENODEV;
 305
 306         /* Enable PCI Express port device */
 307         status = pci_enable_device(dev);
 308         if (status)
 309                 return status;
 310         pci_set_master(dev);
 311         /*
 312          * Initialize service irqs. Don't use service devices that
 313          * require interrupts if there is no way to generate them.
 314          */
 315         status = init_service_irqs(dev, irqs, capabilities);
 316         if (status) {
 317                 capabilities &= PCIE_PORT_SERVICE_VC;
 318                 if (!capabilities)
 319                         goto error_disable;
 320         }
 321
 322         /* Allocate child services if any */
 323         status = -ENODEV;
 324         nr_service = 0;
 325         for (i = 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++) {
 326                 int service = 1 << i;
 327                 if (!(capabilities & service))
 328                         continue;
 329                 if (!pcie_device_init(dev, service, irqs[i]))
 330                         nr_service++;
 331         }
 332         if (!nr_service)
 333                 goto error_cleanup_irqs;
 334
 335         return 0;
 336
 337 error_cleanup_irqs:
 338         cleanup_service_irqs(dev);
 339 error_disable:
 340         pci_disable_device(dev);
 341         return status;
 342 }
 343
 344 #ifdef CONFIG_PM
 345 static int suspend_iter(struct device *dev, void *data)
 346 {
 347         struct pcie_port_service_driver *service_driver;
 348
 349         if ((dev->bus == &pcie_port_bus_type) && dev->driver) {
 350                 service_driver = to_service_driver(dev->driver);
 351                 if (service_driver->suspend)
 352                         service_driver->suspend(to_pcie_device(dev));
 353         }
 354         return 0;
 355 }
 356
 357 /**
 358  * pcie_port_device_suspend - suspend port services associated with a PCIe port
 359  * @dev: PCI Express port to handle
 360  */
 361 int pcie_port_device_suspend(struct device *dev)
 362 {
 363         return device_for_each_child(dev, NULL, suspend_iter);
 364 }
 365
 366 static int resume_iter(struct device *dev, void *data)
 367 {
 368         struct pcie_port_service_driver *service_driver;
 369
 370         if ((dev->bus == &pcie_port_bus_type) &&
 371             (dev->driver)) {
 372                 service_driver = to_service_driver(dev->driver);
 373                 if (service_driver->resume)
 374                         service_driver->resume(to_pcie_device(dev));
 375         }
 376         return 0;
 377 }
 378
 379 /**
 380  * pcie_port_device_suspend - resume port services associated with a PCIe port
 381  * @dev: PCI Express port to handle
 382  */
 383 int pcie_port_device_resume(struct device *dev)
 384 {
 385         return device_for_each_child(dev, NULL, resume_iter);
 386 }
 387 #endif /* PM */
 388
 389 static int remove_iter(struct device *dev, void *data)
 390 {
 391         if (dev->bus == &pcie_port_bus_type) {
 392                 put_device(dev);
 393                 device_unregister(dev);
 394         }
 395         return 0;
 396 }
 397
 398 /**
 399  * pcie_port_device_remove - unregister PCI Express port service devices
 400  * @dev: PCI Express port the service devices to unregister are associated with
 401  *
 402  * Remove PCI Express port service devices associated with given port and
 403  * disable MSI-X or MSI for the port.
 404  */
 405 void pcie_port_device_remove(struct pci_dev *dev)
 406 {
 407         device_for_each_child(&dev->dev, NULL, remove_iter);
 408         cleanup_service_irqs(dev);
 409         pci_disable_device(dev);
 410 }
 411
 412 /**
 413  * pcie_port_probe_service - probe driver for given PCI Express port service
 414  * @dev: PCI Express port service device to probe against
 415  *
 416  * If PCI Express port service driver is registered with
 417  * pcie_port_service_register(), this function will be called by the driver core
 418  * whenever match is found between the driver and a port service device.
 419  */
 420 static int pcie_port_probe_service(struct device *dev)
 421 {
 422         struct pcie_device *pciedev;
 423         struct pcie_port_service_driver *driver;
 424         int status;
 425
 426         if (!dev || !dev->driver)
 427                 return -ENODEV;
 428
 429         driver = to_service_driver(dev->driver);
 430         if (!driver || !driver->probe)
 431                 return -ENODEV;
 432
 433         pciedev = to_pcie_device(dev);
 434         status = driver->probe(pciedev);
 435         if (!status) {
 436                 dev_printk(KERN_DEBUG, dev, "service driver %s loaded\n",
 437                         driver->name);
 438                 get_device(dev);
 439         }
 440         return status;
 441 }
 442
 443 /**
 444  * pcie_port_remove_service - detach driver from given PCI Express port service
 445  * @dev: PCI Express port service device to handle
 446  *
 447  * If PCI Express port service driver is registered with
 448  * pcie_port_service_register(), this function will be called by the driver core
 449  * when device_unregister() is called for the port service device associated
 450  * with the driver.
 451  */
 452 static int pcie_port_remove_service(struct device *dev)
 453 {
 454         struct pcie_device *pciedev;
 455         struct pcie_port_service_driver *driver;
 456
 457         if (!dev || !dev->driver)
 458                 return 0;
 459
 460         pciedev = to_pcie_device(dev);
 461         driver = to_service_driver(dev->driver);
 462         if (driver && driver->remove) {
 463                 dev_printk(KERN_DEBUG, dev, "unloading service driver %s\n",
 464                         driver->name);
 465                 driver->remove(pciedev);
 466                 put_device(dev);
 467         }
 468         return 0;
 469 }
 470
 471 /**
 472  * pcie_port_shutdown_service - shut down given PCI Express port service
 473  * @dev: PCI Express port service device to handle
 474  *
 475  * If PCI Express port service driver is registered with
 476  * pcie_port_service_register(), this function will be called by the driver core
 477  * when device_shutdown() is called for the port service device associated
 478  * with the driver.
 479  */
 480 static void pcie_port_shutdown_service(struct device *dev) {}
 481
 482 /**
 483  * pcie_port_service_register - register PCI Express port service driver
 484  * @new: PCI Express port service driver to register
 485  */
 486 int pcie_port_service_register(struct pcie_port_service_driver *new)
 487 {
 488         new->driver.name = (char *)new->name;
 489         new->driver.bus = &pcie_port_bus_type;
 490         new->driver.probe = pcie_port_probe_service;
 491         new->driver.remove = pcie_port_remove_service;
 492         new->driver.shutdown = pcie_port_shutdown_service;
 493
 494         return driver_register(&new->driver);
 495 }
 496 EXPORT_SYMBOL(pcie_port_service_register);
 497
 498 /**
 499  * pcie_port_service_unregister - unregister PCI Express port service driver
 500  * @drv: PCI Express port service driver to unregister
 501  */
 502 void pcie_port_service_unregister(struct pcie_port_service_driver *drv)
 503 {
 504         driver_unregister(&drv->driver);
 505 }
 506 EXPORT_SYMBOL(pcie_port_service_unregister);