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->parent)
  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                                 struct pci_dev *from)
 166 {
 167         struct pci_dev *pdev;
 168
 169         pci_dev_get(from);
 170         pdev = pci_get_subsys(vendor, device, PCI_ANY_ID, PCI_ANY_ID, from);
 171         pci_dev_put(pdev);
 172         return pdev;
 173 }
 174 EXPORT_SYMBOL(pci_find_device);
 175 #endif /* CONFIG_PCI_LEGACY */
 176
 177 /**
 178  * pci_get_slot - locate PCI device for a given PCI slot
 179  * @bus: PCI bus on which desired PCI device resides
 180  * @devfn: encodes number of PCI slot in which the desired PCI
 181  * device resides and the logical device number within that slot
 182  * in case of multi-function devices.
 183  *
 184  * Given a PCI bus and slot/function number, the desired PCI device
 185  * is located in the list of PCI devices.
 186  * If the device is found, its reference count is increased and this
 187  * function returns a pointer to its data structure.  The caller must
 188  * decrement the reference count by calling pci_dev_put().
 189  * If no device is found, %NULL is returned.
 190  */
 191 struct pci_dev * pci_get_slot(struct pci_bus *bus, unsigned int devfn)
 192 {
 193         struct list_head *tmp;
 194         struct pci_dev *dev;
 195
 196         WARN_ON(in_interrupt());
 197         down_read(&pci_bus_sem);
 198
 199         list_for_each(tmp, &bus->devices) {
 200                 dev = pci_dev_b(tmp);
 201                 if (dev->devfn == devfn)
 202                         goto out;
 203         }
 204
 205         dev = NULL;
 206  out:
 207         pci_dev_get(dev);
 208         up_read(&pci_bus_sem);
 209         return dev;
 210 }
 211
 212 /**
 213  * pci_get_bus_and_slot - locate PCI device from a given PCI bus & slot
 214  * @bus: number of PCI bus on which desired PCI device resides
 215  * @devfn: encodes number of PCI slot in which the desired PCI
 216  * device resides and the logical device number within that slot
 217  * in case of multi-function devices.
 218  *
 219  * Note: the bus/slot search is limited to PCI domain (segment) 0.
 220  *
 221  * Given a PCI bus and slot/function number, the desired PCI device
 222  * is located in system global list of PCI devices.  If the device
 223  * is found, a pointer to its data structure is returned.  If no
 224  * device is found, %NULL is returned. The returned device has its
 225  * reference count bumped by one.
 226  */
 227
 228 struct pci_dev * pci_get_bus_and_slot(unsigned int bus, unsigned int devfn)
 229 {
 230         struct pci_dev *dev = NULL;
 231
 232         while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) {
 233                 if (pci_domain_nr(dev->bus) == 0 &&
 234                    (dev->bus->number == bus && dev->devfn == devfn))
 235                         return dev;
 236         }
 237         return NULL;
 238 }
 239
 240 static int match_pci_dev_by_id(struct device *dev, void *data)
 241 {
 242         struct pci_dev *pdev = to_pci_dev(dev);
 243         struct pci_device_id *id = data;
 244
 245         if (pci_match_one_device(id, pdev))
 246                 return 1;
 247         return 0;
 248 }
 249
 250 /*
 251  * pci_get_dev_by_id - begin or continue searching for a PCI device by id
 252  * @id: pointer to struct pci_device_id to match for the device
 253  * @from: Previous PCI device found in search, or %NULL for new search.
 254  *
 255  * Iterates through the list of known PCI devices.  If a PCI device is found
 256  * with a matching id a pointer to its device structure is returned, and the
 257  * reference count to the device is incremented.  Otherwise, %NULL is returned.
 258  * A new search is initiated by passing %NULL as the @from argument.  Otherwise
 259  * if @from is not %NULL, searches continue from next device on the global
 260  * list.  The reference count for @from is always decremented if it is not
 261  * %NULL.
 262  *
 263  * This is an internal function for use by the other search functions in
 264  * this file.
 265  */
 266 static struct pci_dev *pci_get_dev_by_id(const struct pci_device_id *id,
 267                                          struct pci_dev *from)
 268 {
 269         struct device *dev;
 270         struct device *dev_start = NULL;
 271         struct pci_dev *pdev = NULL;
 272
 273         WARN_ON(in_interrupt());
 274         if (from)
 275                 dev_start = &from->dev;
 276         dev = bus_find_device(&pci_bus_type, dev_start, (void *)id,
 277                               match_pci_dev_by_id);
 278         if (dev)
 279                 pdev = to_pci_dev(dev);
 280         if (from)
 281                 pci_dev_put(from);
 282         return pdev;
 283 }
 284
 285 /**
 286  * pci_get_subsys - begin or continue searching for a PCI device by vendor/subvendor/device/subdevice id
 287  * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
 288  * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
 289  * @ss_vendor: PCI subsystem vendor id to match, or %PCI_ANY_ID to match all vendor ids
 290  * @ss_device: PCI subsystem device id to match, or %PCI_ANY_ID to match all device ids
 291  * @from: Previous PCI device found in search, or %NULL for new search.
 292  *
 293  * Iterates through the list of known PCI devices.  If a PCI device is found
 294  * with a matching @vendor, @device, @ss_vendor and @ss_device, a pointer to its
 295  * device structure is returned, and the reference count to the device is
 296  * incremented.  Otherwise, %NULL is returned.  A new search is initiated by
 297  * passing %NULL as the @from argument.  Otherwise if @from is not %NULL,
 298  * searches continue from next device on the global list.
 299  * The reference count for @from is always decremented if it is not %NULL.
 300  */
 301 struct pci_dev *pci_get_subsys(unsigned int vendor, unsigned int device,
 302                                unsigned int ss_vendor, unsigned int ss_device,
 303                                struct pci_dev *from)
 304 {
 305         struct pci_dev *pdev;
 306         struct pci_device_id *id;
 307
 308         /*
 309          * pci_find_subsys() can be called on the ide_setup() path,
 310          * super-early in boot.  But the down_read() will enable local
 311          * interrupts, which can cause some machines to crash.  So here we
 312          * detect and flag that situation and bail out early.
 313          */
 314         if (unlikely(no_pci_devices()))
 315                 return NULL;
 316
 317         id = kzalloc(sizeof(*id), GFP_KERNEL);
 318         if (!id)
 319                 return NULL;
 320         id->vendor = vendor;
 321         id->device = device;
 322         id->subvendor = ss_vendor;
 323         id->subdevice = ss_device;
 324
 325         pdev = pci_get_dev_by_id(id, from);
 326         kfree(id);
 327
 328         return pdev;
 329 }
 330
 331 /**
 332  * pci_get_device - begin or continue searching for a PCI device by vendor/device id
 333  * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
 334  * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
 335  * @from: Previous PCI device found in search, or %NULL for new search.
 336  *
 337  * Iterates through the list of known PCI devices.  If a PCI device is
 338  * found with a matching @vendor and @device, the reference count to the
 339  * device is incremented and a pointer to its device structure is returned.
 340  * Otherwise, %NULL is returned.  A new search is initiated by passing %NULL
 341  * as the @from argument.  Otherwise if @from is not %NULL, searches continue
 342  * from next device on the global list.  The reference count for @from is
 343  * always decremented if it is not %NULL.
 344  */
 345 struct pci_dev *
 346 pci_get_device(unsigned int vendor, unsigned int device, struct pci_dev *from)
 347 {
 348         return pci_get_subsys(vendor, device, PCI_ANY_ID, PCI_ANY_ID, from);
 349 }
 350
 351 /**
 352  * pci_get_class - begin or continue searching for a PCI device by class
 353  * @class: search for a PCI device with this class designation
 354  * @from: Previous PCI device found in search, or %NULL for new search.
 355  *
 356  * Iterates through the list of known PCI devices.  If a PCI device is
 357  * found with a matching @class, the reference count to the device is
 358  * incremented and a pointer to its device structure is returned.
 359  * Otherwise, %NULL is returned.
 360  * A new search is initiated by passing %NULL as the @from argument.
 361  * Otherwise if @from is not %NULL, searches continue from next device
 362  * on the global list.  The reference count for @from is always decremented
 363  * if it is not %NULL.
 364  */
 365 struct pci_dev *pci_get_class(unsigned int class, struct pci_dev *from)
 366 {
 367         struct pci_dev *dev;
 368         struct pci_device_id *id;
 369
 370         id = kzalloc(sizeof(*id), GFP_KERNEL);
 371         if (!id)
 372                 return NULL;
 373         id->vendor = id->device = id->subvendor = id->subdevice = PCI_ANY_ID;
 374         id->class_mask = PCI_ANY_ID;
 375         id->class = class;
 376
 377         dev = pci_get_dev_by_id(id, from);
 378         kfree(id);
 379         return dev;
 380 }
 381
 382 /**
 383  * pci_dev_present - Returns 1 if device matching the device list is present, 0 if not.
 384  * @ids: A pointer to a null terminated list of struct pci_device_id structures
 385  * that describe the type of PCI device the caller is trying to find.
 386  *
 387  * Obvious fact: You do not have a reference to any device that might be found
 388  * by this function, so if that device is removed from the system right after
 389  * this function is finished, the value will be stale.  Use this function to
 390  * find devices that are usually built into a system, or for a general hint as
 391  * to if another device happens to be present at this specific moment in time.
 392  */
 393 int pci_dev_present(const struct pci_device_id *ids)
 394 {
 395         struct pci_dev *found = NULL;
 396
 397         WARN_ON(in_interrupt());
 398         while (ids->vendor || ids->subvendor || ids->class_mask) {
 399                 found = pci_get_dev_by_id(ids, NULL);
 400                 if (found)
 401                         goto exit;
 402                 ids++;
 403         }
 404 exit:
 405         if (found)
 406                 return 1;
 407         return 0;
 408 }
 409 EXPORT_SYMBOL(pci_dev_present);
 410
 411 /* For boot time work */
 412 EXPORT_SYMBOL(pci_find_bus);
 413 EXPORT_SYMBOL(pci_find_next_bus);
 414 /* For everyone */
 415 EXPORT_SYMBOL(pci_get_device);
 416 EXPORT_SYMBOL(pci_get_subsys);
 417 EXPORT_SYMBOL(pci_get_slot);
 418 EXPORT_SYMBOL(pci_get_bus_and_slot);
 419 EXPORT_SYMBOL(pci_get_class);