drivers/pci/search.c

   1 /*
   2  *      PCI searching functions.
   3  *
   4  *      Copyright (C) 1993 -- 1997 Drew Eckhardt, Frederic Potter,
   5  *                                      David Mosberger-Tang
   6  *      Copyright (C) 1997 -- 2000 Martin Mares <mj@ucw.cz>
   7  *      Copyright (C) 2003 -- 2004 Greg Kroah-Hartman <greg@kroah.com>
   8  */
   9
  10 #include <linux/init.h>
  11 #include <linux/pci.h>
  12 #include <linux/module.h>
  13 #include <linux/interrupt.h>
  14 #include "pci.h"
  15
  16 DECLARE_RWSEM(pci_bus_sem);
  17 /*
  18  * find the upstream PCIE-to-PCI bridge of a PCI device
  19  * if the device is PCIE, return NULL
  20  * if the device isn't connected to a PCIE bridge (that is its parent is a
  21  * legacy PCI bridge and the bridge is directly connected to bus 0), return its
  22  * parent
  23  */
  24 struct pci_dev *
  25 pci_find_upstream_pcie_bridge(struct pci_dev *pdev)
  26 {
  27         struct pci_dev *tmp = NULL;
  28
  29         if (pdev->is_pcie)
  30                 return NULL;
  31         while (1) {
  32                 if (!pdev->bus->self)
  33                         break;
  34                 pdev = pdev->bus->self;
  35                 /* a p2p bridge */
  36                 if (!pdev->is_pcie) {
  37                         tmp = pdev;
  38                         continue;
  39                 }
  40                 /* PCI device should connect to a PCIE bridge */
  41                 if (pdev->pcie_type != PCI_EXP_TYPE_PCI_BRIDGE) {
  42                         /* Busted hardware? */
  43                         WARN_ON_ONCE(1);
  44                         return NULL;
  45                 }
  46                 return pdev;
  47         }
  48
  49         return tmp;
  50 }
  51
  52 static struct pci_bus *pci_do_find_bus(struct pci_bus *bus, unsigned char busnr)
  53 {
  54         struct pci_bus* child;
  55         struct list_head *tmp;
  56
  57         if(bus->number == busnr)
  58                 return bus;
  59
  60         list_for_each(tmp, &bus->children) {
  61                 child = pci_do_find_bus(pci_bus_b(tmp), busnr);
  62                 if(child)
  63                         return child;
  64         }
  65         return NULL;
  66 }
  67
  68 /**
  69  * pci_find_bus - locate PCI bus from a given domain and bus number
  70  * @domain: number of PCI domain to search
  71  * @busnr: number of desired PCI bus
  72  *
  73  * Given a PCI bus number and domain number, the desired PCI bus is located
  74  * in the global list of PCI buses.  If the bus is found, a pointer to its
  75  * data structure is returned.  If no bus is found, %NULL is returned.
  76  */
  77 struct pci_bus * pci_find_bus(int domain, int busnr)
  78 {
  79         struct pci_bus *bus = NULL;
  80         struct pci_bus *tmp_bus;
  81
  82         while ((bus = pci_find_next_bus(bus)) != NULL)  {
  83                 if (pci_domain_nr(bus) != domain)
  84                         continue;
  85                 tmp_bus = pci_do_find_bus(bus, busnr);
  86                 if (tmp_bus)
  87                         return tmp_bus;
  88         }
  89         return NULL;
  90 }
  91
  92 /**
  93  * pci_find_next_bus - begin or continue searching for a PCI bus
  94  * @from: Previous PCI bus found, or %NULL for new search.
  95  *
  96  * Iterates through the list of known PCI busses.  A new search is
  97  * initiated by passing %NULL as the @from argument.  Otherwise if
  98  * @from is not %NULL, searches continue from next device on the
  99  * global list.
 100  */
 101 struct pci_bus *
 102 pci_find_next_bus(const struct pci_bus *from)
 103 {
 104         struct list_head *n;
 105         struct pci_bus *b = NULL;
 106
 107         WARN_ON(in_interrupt());
 108         down_read(&pci_bus_sem);
 109         n = from ? from->node.next : pci_root_buses.next;
 110         if (n != &pci_root_buses)
 111                 b = pci_bus_b(n);
 112         up_read(&pci_bus_sem);
 113         return b;
 114 }
 115
 116 #ifdef CONFIG_PCI_LEGACY
 117
 118 /**
 119  * pci_find_slot - locate PCI device from a given PCI slot
 120  * @bus: number of PCI bus on which desired PCI device resides
 121  * @devfn: encodes number of PCI slot in which the desired PCI
 122  * device resides and the logical device number within that slot
 123  * in case of multi-function devices.
 124  *
 125  * Given a PCI bus and slot/function number, the desired PCI device
 126  * is located in system global list of PCI devices.  If the device
 127  * is found, a pointer to its data structure is returned.  If no
 128  * device is found, %NULL is returned.
 129  */
 130 struct pci_dev *
 131 pci_find_slot(unsigned int bus, unsigned int devfn)
 132 {
 133         struct pci_dev *dev = NULL;
 134
 135         while ((dev = pci_find_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) {
 136                 if (dev->bus->number == bus && dev->devfn == devfn)
 137                         return dev;
 138         }
 139         return NULL;
 140 }
 141
 142 #endif /* CONFIG_PCI_LEGACY */
 143
 144 /**
 145  * pci_get_slot - locate PCI device for a given PCI slot
 146  * @bus: PCI bus on which desired PCI device resides
 147  * @devfn: encodes number of PCI slot in which the desired PCI
 148  * device resides and the logical device number within that slot
 149  * in case of multi-function devices.
 150  *
 151  * Given a PCI bus and slot/function number, the desired PCI device
 152  * is located in the list of PCI devices.
 153  * If the device is found, its reference count is increased and this
 154  * function returns a pointer to its data structure.  The caller must
 155  * decrement the reference count by calling pci_dev_put().
 156  * If no device is found, %NULL is returned.
 157  */
 158 struct pci_dev * pci_get_slot(struct pci_bus *bus, unsigned int devfn)
 159 {
 160         struct list_head *tmp;
 161         struct pci_dev *dev;
 162
 163         WARN_ON(in_interrupt());
 164         down_read(&pci_bus_sem);
 165
 166         list_for_each(tmp, &bus->devices) {
 167                 dev = pci_dev_b(tmp);
 168                 if (dev->devfn == devfn)
 169                         goto out;
 170         }
 171
 172         dev = NULL;
 173  out:
 174         pci_dev_get(dev);
 175         up_read(&pci_bus_sem);
 176         return dev;
 177 }
 178
 179 /**
 180  * pci_get_bus_and_slot - locate PCI device from a given PCI bus & slot
 181  * @bus: number of PCI bus on which desired PCI device resides
 182  * @devfn: encodes number of PCI slot in which the desired PCI
 183  * device resides and the logical device number within that slot
 184  * in case of multi-function devices.
 185  *
 186  * Note: the bus/slot search is limited to PCI domain (segment) 0.
 187  *
 188  * Given a PCI bus and slot/function number, the desired PCI device
 189  * is located in system global list of PCI devices.  If the device
 190  * is found, a pointer to its data structure is returned.  If no
 191  * device is found, %NULL is returned. The returned device has its
 192  * reference count bumped by one.
 193  */
 194
 195 struct pci_dev * pci_get_bus_and_slot(unsigned int bus, unsigned int devfn)
 196 {
 197         struct pci_dev *dev = NULL;
 198
 199         while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) {
 200                 if (pci_domain_nr(dev->bus) == 0 &&
 201                    (dev->bus->number == bus && dev->devfn == devfn))
 202                         return dev;
 203         }
 204         return NULL;
 205 }
 206
 207 #ifdef CONFIG_PCI_LEGACY
 208 /**
 209  * pci_find_subsys - begin or continue searching for a PCI device by vendor/subvendor/device/subdevice id
 210  * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
 211  * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
 212  * @ss_vendor: PCI subsystem vendor id to match, or %PCI_ANY_ID to match all vendor ids
 213  * @ss_device: PCI subsystem device id to match, or %PCI_ANY_ID to match all device ids
 214  * @from: Previous PCI device found in search, or %NULL for new search.
 215  *
 216  * Iterates through the list of known PCI devices.  If a PCI device is
 217  * found with a matching @vendor, @device, @ss_vendor and @ss_device, a
 218  * pointer to its device structure is returned.  Otherwise, %NULL is returned.
 219  * A new search is initiated by passing %NULL as the @from argument.
 220  * Otherwise if @from is not %NULL, searches continue from next device
 221  * on the global list.
 222  *
 223  * NOTE: Do not use this function any more; use pci_get_subsys() instead, as
 224  * the PCI device returned by this function can disappear at any moment in
 225  * time.
 226  */
 227 static struct pci_dev * pci_find_subsys(unsigned int vendor,
 228                                         unsigned int device,
 229                                         unsigned int ss_vendor,
 230                                         unsigned int ss_device,
 231                                         const struct pci_dev *from)
 232 {
 233         struct list_head *n;
 234         struct pci_dev *dev;
 235
 236         WARN_ON(in_interrupt());
 237
 238         /*
 239          * pci_find_subsys() can be called on the ide_setup() path, super-early
 240          * in boot.  But the down_read() will enable local interrupts, which
 241          * can cause some machines to crash.  So here we detect and flag that
 242          * situation and bail out early.
 243          */
 244         if (unlikely(no_pci_devices()))
 245                 return NULL;
 246         down_read(&pci_bus_sem);
 247         n = from ? from->global_list.next : pci_devices.next;
 248
 249         while (n && (n != &pci_devices)) {
 250                 dev = pci_dev_g(n);
 251                 if ((vendor == PCI_ANY_ID || dev->vendor == vendor) &&
 252                     (device == PCI_ANY_ID || dev->device == device) &&
 253                     (ss_vendor == PCI_ANY_ID || dev->subsystem_vendor == ss_vendor) &&
 254                     (ss_device == PCI_ANY_ID || dev->subsystem_device == ss_device))
 255                         goto exit;
 256                 n = n->next;
 257         }
 258         dev = NULL;
 259 exit:
 260         up_read(&pci_bus_sem);
 261         return dev;
 262 }
 263
 264 /**
 265  * pci_find_device - begin or continue searching for a PCI device by vendor/device id
 266  * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
 267  * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
 268  * @from: Previous PCI device found in search, or %NULL for new search.
 269  *
 270  * Iterates through the list of known PCI devices.  If a PCI device is found
 271  * with a matching @vendor and @device, a pointer to its device structure is
 272  * returned.  Otherwise, %NULL is returned.
 273  * A new search is initiated by passing %NULL as the @from argument.
 274  * Otherwise if @from is not %NULL, searches continue from next device
 275  * on the global list.
 276  *
 277  * NOTE: Do not use this function any more; use pci_get_device() instead, as
 278  * the PCI device returned by this function can disappear at any moment in
 279  * time.
 280  */
 281 struct pci_dev *
 282 pci_find_device(unsigned int vendor, unsigned int device, const struct pci_dev *from)
 283 {
 284         return pci_find_subsys(vendor, device, PCI_ANY_ID, PCI_ANY_ID, from);
 285 }
 286 #endif /* CONFIG_PCI_LEGACY */
 287
 288 /**
 289  * pci_get_subsys - begin or continue searching for a PCI device by vendor/subvendor/device/subdevice id
 290  * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
 291  * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
 292  * @ss_vendor: PCI subsystem vendor id to match, or %PCI_ANY_ID to match all vendor ids
 293  * @ss_device: PCI subsystem device id to match, or %PCI_ANY_ID to match all device ids
 294  * @from: Previous PCI device found in search, or %NULL for new search.
 295  *
 296  * Iterates through the list of known PCI devices.  If a PCI device is found
 297  * with a matching @vendor, @device, @ss_vendor and @ss_device, a pointer to its
 298  * device structure is returned, and the reference count to the device is
 299  * incremented.  Otherwise, %NULL is returned.  A new search is initiated by
 300  * passing %NULL as the @from argument.  Otherwise if @from is not %NULL,
 301  * searches continue from next device on the global list.
 302  * The reference count for @from is always decremented if it is not %NULL.
 303  */
 304 struct pci_dev *
 305 pci_get_subsys(unsigned int vendor, unsigned int device,
 306                unsigned int ss_vendor, unsigned int ss_device,
 307                struct pci_dev *from)
 308 {
 309         struct list_head *n;
 310         struct pci_dev *dev;
 311
 312         WARN_ON(in_interrupt());
 313
 314         /*
 315          * pci_get_subsys() can potentially be called by drivers super-early
 316          * in boot.  But the down_read() will enable local interrupts, which
 317          * can cause some machines to crash.  So here we detect and flag that
 318          * situation and bail out early.
 319          */
 320         if (unlikely(no_pci_devices()))
 321                 return NULL;
 322         down_read(&pci_bus_sem);
 323         n = from ? from->global_list.next : pci_devices.next;
 324
 325         while (n && (n != &pci_devices)) {
 326                 dev = pci_dev_g(n);
 327                 if ((vendor == PCI_ANY_ID || dev->vendor == vendor) &&
 328                     (device == PCI_ANY_ID || dev->device == device) &&
 329                     (ss_vendor == PCI_ANY_ID || dev->subsystem_vendor == ss_vendor) &&
 330                     (ss_device == PCI_ANY_ID || dev->subsystem_device == ss_device))
 331                         goto exit;
 332                 n = n->next;
 333         }
 334         dev = NULL;
 335 exit:
 336         dev = pci_dev_get(dev);
 337         up_read(&pci_bus_sem);
 338         pci_dev_put(from);
 339         return dev;
 340 }
 341
 342 /**
 343  * pci_get_device - begin or continue searching for a PCI device by vendor/device id
 344  * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
 345  * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
 346  * @from: Previous PCI device found in search, or %NULL for new search.
 347  *
 348  * Iterates through the list of known PCI devices.  If a PCI device is
 349  * found with a matching @vendor and @device, the reference count to the
 350  * device is incremented and a pointer to its device structure is returned.
 351  * Otherwise, %NULL is returned.  A new search is initiated by passing %NULL
 352  * as the @from argument.  Otherwise if @from is not %NULL, searches continue
 353  * from next device on the global list.  The reference count for @from is
 354  * always decremented if it is not %NULL.
 355  */
 356 struct pci_dev *
 357 pci_get_device(unsigned int vendor, unsigned int device, struct pci_dev *from)
 358 {
 359         return pci_get_subsys(vendor, device, PCI_ANY_ID, PCI_ANY_ID, from);
 360 }
 361
 362 /**
 363  * pci_get_device_reverse - begin or continue searching for a PCI device by vendor/device id
 364  * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
 365  * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
 366  * @from: Previous PCI device found in search, or %NULL for new search.
 367  *
 368  * Iterates through the list of known PCI devices in the reverse order of
 369  * pci_get_device.
 370  * If a PCI device is found with a matching @vendor and @device, the reference
 371  * count to the  device is incremented and a pointer to its device structure
 372  * is returned Otherwise, %NULL is returned.  A new search is initiated by
 373  * passing %NULL as the @from argument.  Otherwise if @from is not %NULL,
 374  * searches continue from next device on the global list.  The reference
 375  * count for @from is always decremented if it is not %NULL.
 376  */
 377 struct pci_dev *
 378 pci_get_device_reverse(unsigned int vendor, unsigned int device, struct pci_dev *from)
 379 {
 380         struct list_head *n;
 381         struct pci_dev *dev;
 382
 383         WARN_ON(in_interrupt());
 384         down_read(&pci_bus_sem);
 385         n = from ? from->global_list.prev : pci_devices.prev;
 386
 387         while (n && (n != &pci_devices)) {
 388                 dev = pci_dev_g(n);
 389                 if ((vendor == PCI_ANY_ID || dev->vendor == vendor) &&
 390                     (device == PCI_ANY_ID || dev->device == device))
 391                         goto exit;
 392                 n = n->prev;
 393         }
 394         dev = NULL;
 395 exit:
 396         dev = pci_dev_get(dev);
 397         up_read(&pci_bus_sem);
 398         pci_dev_put(from);
 399         return dev;
 400 }
 401
 402 /**
 403  * pci_get_class - begin or continue searching for a PCI device by class
 404  * @class: search for a PCI device with this class designation
 405  * @from: Previous PCI device found in search, or %NULL for new search.
 406  *
 407  * Iterates through the list of known PCI devices.  If a PCI device is
 408  * found with a matching @class, the reference count to the device is
 409  * incremented and a pointer to its device structure is returned.
 410  * Otherwise, %NULL is returned.
 411  * A new search is initiated by passing %NULL as the @from argument.
 412  * Otherwise if @from is not %NULL, searches continue from next device
 413  * on the global list.  The reference count for @from is always decremented
 414  * if it is not %NULL.
 415  */
 416 struct pci_dev *pci_get_class(unsigned int class, struct pci_dev *from)
 417 {
 418         struct list_head *n;
 419         struct pci_dev *dev;
 420
 421         WARN_ON(in_interrupt());
 422         down_read(&pci_bus_sem);
 423         n = from ? from->global_list.next : pci_devices.next;
 424
 425         while (n && (n != &pci_devices)) {
 426                 dev = pci_dev_g(n);
 427                 if (dev->class == class)
 428                         goto exit;
 429                 n = n->next;
 430         }
 431         dev = NULL;
 432 exit:
 433         dev = pci_dev_get(dev);
 434         up_read(&pci_bus_sem);
 435         pci_dev_put(from);
 436         return dev;
 437 }
 438
 439 const struct pci_device_id *pci_find_present(const struct pci_device_id *ids)
 440 {
 441         struct pci_dev *dev;
 442         const struct pci_device_id *found = NULL;
 443
 444         WARN_ON(in_interrupt());
 445         down_read(&pci_bus_sem);
 446         while (ids->vendor || ids->subvendor || ids->class_mask) {
 447                 list_for_each_entry(dev, &pci_devices, global_list) {
 448                         if ((found = pci_match_one_device(ids, dev)) != NULL)
 449                                 goto exit;
 450                 }
 451                 ids++;
 452         }
 453 exit:
 454         up_read(&pci_bus_sem);
 455         return found;
 456 }
 457
 458 /**
 459  * pci_dev_present - Returns 1 if device matching the device list is present, 0 if not.
 460  * @ids: A pointer to a null terminated list of struct pci_device_id structures
 461  * that describe the type of PCI device the caller is trying to find.
 462  *
 463  * Obvious fact: You do not have a reference to any device that might be found
 464  * by this function, so if that device is removed from the system right after
 465  * this function is finished, the value will be stale.  Use this function to
 466  * find devices that are usually built into a system, or for a general hint as
 467  * to if another device happens to be present at this specific moment in time.
 468  */
 469 int pci_dev_present(const struct pci_device_id *ids)
 470 {
 471         return pci_find_present(ids) == NULL ? 0 : 1;
 472 }
 473
 474 EXPORT_SYMBOL(pci_dev_present);
 475 EXPORT_SYMBOL(pci_find_present);
 476
 477 #ifdef CONFIG_PCI_LEGACY
 478 EXPORT_SYMBOL(pci_find_device);
 479 EXPORT_SYMBOL(pci_find_slot);
 480 #endif /* CONFIG_PCI_LEGACY */
 481
 482 /* For boot time work */
 483 EXPORT_SYMBOL(pci_find_bus);
 484 EXPORT_SYMBOL(pci_find_next_bus);
 485 /* For everyone */
 486 EXPORT_SYMBOL(pci_get_device);
 487 EXPORT_SYMBOL(pci_get_device_reverse);
 488 EXPORT_SYMBOL(pci_get_subsys);
 489 EXPORT_SYMBOL(pci_get_slot);
 490 EXPORT_SYMBOL(pci_get_bus_and_slot);
 491 EXPORT_SYMBOL(pci_get_class);