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  * pci_find_slot - locate PCI device from a given PCI slot
 119  * @bus: number of PCI bus on which desired PCI device resides
 120  * @devfn: encodes number of PCI slot in which the desired PCI
 121  * device resides and the logical device number within that slot
 122  * in case of multi-function devices.
 123  *
 124  * Given a PCI bus and slot/function number, the desired PCI device
 125  * is located in system global list of PCI devices.  If the device
 126  * is found, a pointer to its data structure is returned.  If no
 127  * device is found, %NULL is returned.
 128  *
 129  * NOTE: Do not use this function any more; use pci_get_slot() instead, as
 130  * the PCI device returned by this function can disappear at any moment in
 131  * time.
 132  */
 133 struct pci_dev *pci_find_slot(unsigned int bus, unsigned int devfn)
 134 {
 135         struct pci_dev *dev = NULL;
 136
 137         while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) {
 138                 if (dev->bus->number == bus && dev->devfn == devfn) {
 139                         pci_dev_put(dev);
 140                         return dev;
 141                 }
 142         }
 143         return NULL;
 144 }
 145 EXPORT_SYMBOL(pci_find_slot);
 146
 147 /**
 148  * pci_find_device - begin or continue searching for a PCI device by vendor/device id
 149  * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
 150  * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
 151  * @from: Previous PCI device found in search, or %NULL for new search.
 152  *
 153  * Iterates through the list of known PCI devices.  If a PCI device is found
 154  * with a matching @vendor and @device, a pointer to its device structure is
 155  * returned.  Otherwise, %NULL is returned.
 156  * A new search is initiated by passing %NULL as the @from argument.
 157  * Otherwise if @from is not %NULL, searches continue from next device
 158  * on the global list.
 159  *
 160  * NOTE: Do not use this function any more; use pci_get_device() instead, as
 161  * the PCI device returned by this function can disappear at any moment in
 162  * time.
 163  */
 164 struct pci_dev *pci_find_device(unsigned int vendor, unsigned int device,
 165                                 const struct pci_dev *from)
 166 {
 167         struct pci_dev *pdev;
 168
 169         pdev = pci_get_subsys(vendor, device, PCI_ANY_ID, PCI_ANY_ID, from);
 170         pci_dev_put(pdev);
 171         return pdev;
 172 }
 173 EXPORT_SYMBOL(pci_find_device);
 174 #endif /* CONFIG_PCI_LEGACY */
 175
 176 /**
 177  * pci_get_slot - locate PCI device for a given PCI slot
 178  * @bus: PCI bus on which desired PCI device resides
 179  * @devfn: encodes number of PCI slot in which the desired PCI
 180  * device resides and the logical device number within that slot
 181  * in case of multi-function devices.
 182  *
 183  * Given a PCI bus and slot/function number, the desired PCI device
 184  * is located in the list of PCI devices.
 185  * If the device is found, its reference count is increased and this
 186  * function returns a pointer to its data structure.  The caller must
 187  * decrement the reference count by calling pci_dev_put().
 188  * If no device is found, %NULL is returned.
 189  */
 190 struct pci_dev * pci_get_slot(struct pci_bus *bus, unsigned int devfn)
 191 {
 192         struct list_head *tmp;
 193         struct pci_dev *dev;
 194
 195         WARN_ON(in_interrupt());
 196         down_read(&pci_bus_sem);
 197
 198         list_for_each(tmp, &bus->devices) {
 199                 dev = pci_dev_b(tmp);
 200                 if (dev->devfn == devfn)
 201                         goto out;
 202         }
 203
 204         dev = NULL;
 205  out:
 206         pci_dev_get(dev);
 207         up_read(&pci_bus_sem);
 208         return dev;
 209 }
 210
 211 /**
 212  * pci_get_bus_and_slot - locate PCI device from a given PCI bus & slot
 213  * @bus: number of PCI bus on which desired PCI device resides
 214  * @devfn: encodes number of PCI slot in which the desired PCI
 215  * device resides and the logical device number within that slot
 216  * in case of multi-function devices.
 217  *
 218  * Note: the bus/slot search is limited to PCI domain (segment) 0.
 219  *
 220  * Given a PCI bus and slot/function number, the desired PCI device
 221  * is located in system global list of PCI devices.  If the device
 222  * is found, a pointer to its data structure is returned.  If no
 223  * device is found, %NULL is returned. The returned device has its
 224  * reference count bumped by one.
 225  */
 226
 227 struct pci_dev * pci_get_bus_and_slot(unsigned int bus, unsigned int devfn)
 228 {
 229         struct pci_dev *dev = NULL;
 230
 231         while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) {
 232                 if (pci_domain_nr(dev->bus) == 0 &&
 233                    (dev->bus->number == bus && dev->devfn == devfn))
 234                         return dev;
 235         }
 236         return NULL;
 237 }
 238
 239 static int match_pci_dev_by_id(struct device *dev, void *data)
 240 {
 241         struct pci_dev *pdev = to_pci_dev(dev);
 242         struct pci_device_id *id = data;
 243
 244         if (pci_match_one_device(id, pdev))
 245                 return 1;
 246         return 0;
 247 }
 248
 249 /*
 250  * pci_get_dev_by_id - begin or continue searching for a PCI device by id
 251  * @id: pointer to struct pci_device_id to match for the device
 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 id a pointer to its device structure is returned, and the
 256  * reference count to the device is incremented.  Otherwise, %NULL is returned.
 257  * A new search is initiated by passing %NULL as the @from argument.  Otherwise
 258  * if @from is not %NULL, searches continue from next device on the global
 259  * list.  The reference count for @from is always decremented if it is not
 260  * %NULL.
 261  *
 262  * This is an internal function for use by the other search functions in
 263  * this file.
 264  */
 265 static struct pci_dev *pci_get_dev_by_id(const struct pci_device_id *id,
 266                                          const struct pci_dev *from)
 267 {
 268         struct device *dev;
 269         struct device *dev_start = NULL;
 270         struct pci_dev *pdev = NULL;
 271
 272         WARN_ON(in_interrupt());
 273         if (from) {
 274                 /* FIXME
 275                  * take the cast off, when bus_find_device is made const.
 276                  */
 277                 dev_start = (struct device *)&from->dev;
 278         }
 279         dev = bus_find_device(&pci_bus_type, dev_start, (void *)id,
 280                               match_pci_dev_by_id);
 281         if (dev)
 282                 pdev = to_pci_dev(dev);
 283         return pdev;
 284 }
 285
 286 /**
 287  * pci_get_subsys - begin or continue searching for a PCI device by vendor/subvendor/device/subdevice id
 288  * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
 289  * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
 290  * @ss_vendor: PCI subsystem vendor id to match, or %PCI_ANY_ID to match all vendor ids
 291  * @ss_device: PCI subsystem device id to match, or %PCI_ANY_ID to match all device ids
 292  * @from: Previous PCI device found in search, or %NULL for new search.
 293  *
 294  * Iterates through the list of known PCI devices.  If a PCI device is found
 295  * with a matching @vendor, @device, @ss_vendor and @ss_device, a pointer to its
 296  * device structure is returned, and the reference count to the device is
 297  * incremented.  Otherwise, %NULL is returned.  A new search is initiated by
 298  * passing %NULL as the @from argument.  Otherwise if @from is not %NULL,
 299  * searches continue from next device on the global list.
 300  * The reference count for @from is always decremented if it is not %NULL.
 301  */
 302 struct pci_dev *pci_get_subsys(unsigned int vendor, unsigned int device,
 303                                unsigned int ss_vendor, unsigned int ss_device,
 304                                const struct pci_dev *from)
 305 {
 306         struct pci_dev *pdev;
 307         struct pci_device_id *id;
 308
 309         /*
 310          * pci_find_subsys() can be called on the ide_setup() path,
 311          * super-early in boot.  But the down_read() will enable local
 312          * interrupts, which can cause some machines to crash.  So here we
 313          * detect and flag that situation and bail out early.
 314          */
 315         if (unlikely(no_pci_devices()))
 316                 return NULL;
 317
 318         id = kzalloc(sizeof(*id), GFP_KERNEL);
 319         if (!id)
 320                 return NULL;
 321         id->vendor = vendor;
 322         id->device = device;
 323         id->subvendor = ss_vendor;
 324         id->subdevice = ss_device;
 325
 326         pdev = pci_get_dev_by_id(id, from);
 327         kfree(id);
 328
 329         return pdev;
 330 }
 331
 332 /**
 333  * pci_get_device - begin or continue searching for a PCI device by vendor/device id
 334  * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
 335  * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
 336  * @from: Previous PCI device found in search, or %NULL for new search.
 337  *
 338  * Iterates through the list of known PCI devices.  If a PCI device is
 339  * found with a matching @vendor and @device, the reference count to the
 340  * device is incremented and a pointer to its device structure is returned.
 341  * Otherwise, %NULL is returned.  A new search is initiated by passing %NULL
 342  * as the @from argument.  Otherwise if @from is not %NULL, searches continue
 343  * from next device on the global list.  The reference count for @from is
 344  * always decremented if it is not %NULL.
 345  */
 346 struct pci_dev *
 347 pci_get_device(unsigned int vendor, unsigned int device, struct pci_dev *from)
 348 {
 349         return pci_get_subsys(vendor, device, PCI_ANY_ID, PCI_ANY_ID, from);
 350 }
 351
 352 /**
 353  * pci_get_class - begin or continue searching for a PCI device by class
 354  * @class: search for a PCI device with this class designation
 355  * @from: Previous PCI device found in search, or %NULL for new search.
 356  *
 357  * Iterates through the list of known PCI devices.  If a PCI device is
 358  * found with a matching @class, the reference count to the device is
 359  * incremented and a pointer to its device structure is returned.
 360  * Otherwise, %NULL is returned.
 361  * A new search is initiated by passing %NULL as the @from argument.
 362  * Otherwise if @from is not %NULL, searches continue from next device
 363  * on the global list.  The reference count for @from is always decremented
 364  * if it is not %NULL.
 365  */
 366 struct pci_dev *pci_get_class(unsigned int class, struct pci_dev *from)
 367 {
 368         struct pci_dev *dev;
 369         struct pci_device_id *id;
 370
 371         id = kzalloc(sizeof(*id), GFP_KERNEL);
 372         if (!id)
 373                 return NULL;
 374         id->vendor = id->device = id->subvendor = id->subdevice = PCI_ANY_ID;
 375         id->class_mask = PCI_ANY_ID;
 376         id->class = class;
 377
 378         dev = pci_get_dev_by_id(id, from);
 379         kfree(id);
 380         return dev;
 381 }
 382
 383 /**
 384  * pci_dev_present - Returns 1 if device matching the device list is present, 0 if not.
 385  * @ids: A pointer to a null terminated list of struct pci_device_id structures
 386  * that describe the type of PCI device the caller is trying to find.
 387  *
 388  * Obvious fact: You do not have a reference to any device that might be found
 389  * by this function, so if that device is removed from the system right after
 390  * this function is finished, the value will be stale.  Use this function to
 391  * find devices that are usually built into a system, or for a general hint as
 392  * to if another device happens to be present at this specific moment in time.
 393  */
 394 int pci_dev_present(const struct pci_device_id *ids)
 395 {
 396         struct pci_dev *found = NULL;
 397
 398         WARN_ON(in_interrupt());
 399         while (ids->vendor || ids->subvendor || ids->class_mask) {
 400                 found = pci_get_dev_by_id(ids, NULL);
 401                 if (found)
 402                         goto exit;
 403                 ids++;
 404         }
 405 exit:
 406         if (found)
 407                 return 1;
 408         return 0;
 409 }
 410 EXPORT_SYMBOL(pci_dev_present);
 411
 412 /* For boot time work */
 413 EXPORT_SYMBOL(pci_find_bus);
 414 EXPORT_SYMBOL(pci_find_next_bus);
 415 /* For everyone */
 416 EXPORT_SYMBOL(pci_get_device);
 417 EXPORT_SYMBOL(pci_get_subsys);
 418 EXPORT_SYMBOL(pci_get_slot);
 419 EXPORT_SYMBOL(pci_get_bus_and_slot);
 420 EXPORT_SYMBOL(pci_get_class);