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