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/pci.h>
  11 #include <linux/slab.h>
  12 #include <linux/module.h>
  13 #include <linux/interrupt.h>
  14 #include "pci.h"
  15
  16 DECLARE_RWSEM(pci_bus_sem);
  17 EXPORT_SYMBOL_GPL(pci_bus_sem);
  18
  19 /*
  20  * pci_for_each_dma_alias - Iterate over DMA aliases for a device
  21  * @pdev: starting downstream device
  22  * @fn: function to call for each alias
  23  * @data: opaque data to pass to @fn
  24  *
  25  * Starting @pdev, walk up the bus calling @fn for each possible alias
  26  * of @pdev at the root bus.
  27  */
  28 int pci_for_each_dma_alias(struct pci_dev *pdev,
  29                            int (*fn)(struct pci_dev *pdev,
  30                                      u16 alias, void *data), void *data)
  31 {
  32         struct pci_bus *bus;
  33         int ret;
  34
  35         ret = fn(pdev, PCI_DEVID(pdev->bus->number, pdev->devfn), data);
  36         if (ret)
  37                 return ret;
  38
  39         /*
  40          * If the device is broken and uses an alias requester ID for
  41          * DMA, iterate over that too.
  42          */
  43         if (unlikely(pdev->dev_flags & PCI_DEV_FLAGS_DMA_ALIAS_DEVFN)) {
  44                 ret = fn(pdev, PCI_DEVID(pdev->bus->number,
  45                                          pdev->dma_alias_devfn), data);
  46                 if (ret)
  47                         return ret;
  48         }
  49
  50         for (bus = pdev->bus; !pci_is_root_bus(bus); bus = bus->parent) {
  51                 struct pci_dev *tmp;
  52
  53                 /* Skip virtual buses */
  54                 if (!bus->self)
  55                         continue;
  56
  57                 tmp = bus->self;
  58
  59                 /*
  60                  * PCIe-to-PCI/X bridges alias transactions from downstream
  61                  * devices using the subordinate bus number (PCI Express to
  62                  * PCI/PCI-X Bridge Spec, rev 1.0, sec 2.3).  For all cases
  63                  * where the upstream bus is PCI/X we alias to the bridge
  64                  * (there are various conditions in the previous reference
  65                  * where the bridge may take ownership of transactions, even
  66                  * when the secondary interface is PCI-X).
  67                  */
  68                 if (pci_is_pcie(tmp)) {
  69                         switch (pci_pcie_type(tmp)) {
  70                         case PCI_EXP_TYPE_ROOT_PORT:
  71                         case PCI_EXP_TYPE_UPSTREAM:
  72                         case PCI_EXP_TYPE_DOWNSTREAM:
  73                                 continue;
  74                         case PCI_EXP_TYPE_PCI_BRIDGE:
  75                                 ret = fn(tmp,
  76                                          PCI_DEVID(tmp->subordinate->number,
  77                                                    PCI_DEVFN(0, 0)), data);
  78                                 if (ret)
  79                                         return ret;
  80                                 continue;
  81                         case PCI_EXP_TYPE_PCIE_BRIDGE:
  82                                 ret = fn(tmp,
  83                                          PCI_DEVID(tmp->bus->number,
  84                                                    tmp->devfn), data);
  85                                 if (ret)
  86                                         return ret;
  87                                 continue;
  88                         }
  89                 } else {
  90                         if (tmp->dev_flags & PCI_DEV_FLAG_PCIE_BRIDGE_ALIAS)
  91                                 ret = fn(tmp,
  92                                          PCI_DEVID(tmp->subordinate->number,
  93                                                    PCI_DEVFN(0, 0)), data);
  94                         else
  95                                 ret = fn(tmp,
  96                                          PCI_DEVID(tmp->bus->number,
  97                                                    tmp->devfn), data);
  98                         if (ret)
  99                                 return ret;
 100                 }
 101         }
 102
 103         return ret;
 104 }
 105
 106 /*
 107  * find the upstream PCIe-to-PCI bridge of a PCI device
 108  * if the device is PCIE, return NULL
 109  * if the device isn't connected to a PCIe bridge (that is its parent is a
 110  * legacy PCI bridge and the bridge is directly connected to bus 0), return its
 111  * parent
 112  */
 113 struct pci_dev *pci_find_upstream_pcie_bridge(struct pci_dev *pdev)
 114 {
 115         struct pci_dev *tmp = NULL;
 116
 117         if (pci_is_pcie(pdev))
 118                 return NULL;
 119         while (1) {
 120                 if (pci_is_root_bus(pdev->bus))
 121                         break;
 122                 pdev = pdev->bus->self;
 123                 /* a p2p bridge */
 124                 if (!pci_is_pcie(pdev)) {
 125                         tmp = pdev;
 126                         continue;
 127                 }
 128                 /* PCI device should connect to a PCIe bridge */
 129                 if (pci_pcie_type(pdev) != PCI_EXP_TYPE_PCI_BRIDGE) {
 130                         /* Busted hardware? */
 131                         WARN_ON_ONCE(1);
 132                         return NULL;
 133                 }
 134                 return pdev;
 135         }
 136
 137         return tmp;
 138 }
 139
 140 static struct pci_bus *pci_do_find_bus(struct pci_bus *bus, unsigned char busnr)
 141 {
 142         struct pci_bus *child;
 143         struct pci_bus *tmp;
 144
 145         if (bus->number == busnr)
 146                 return bus;
 147
 148         list_for_each_entry(tmp, &bus->children, node) {
 149                 child = pci_do_find_bus(tmp, busnr);
 150                 if (child)
 151                         return child;
 152         }
 153         return NULL;
 154 }
 155
 156 /**
 157  * pci_find_bus - locate PCI bus from a given domain and bus number
 158  * @domain: number of PCI domain to search
 159  * @busnr: number of desired PCI bus
 160  *
 161  * Given a PCI bus number and domain number, the desired PCI bus is located
 162  * in the global list of PCI buses.  If the bus is found, a pointer to its
 163  * data structure is returned.  If no bus is found, %NULL is returned.
 164  */
 165 struct pci_bus *pci_find_bus(int domain, int busnr)
 166 {
 167         struct pci_bus *bus = NULL;
 168         struct pci_bus *tmp_bus;
 169
 170         while ((bus = pci_find_next_bus(bus)) != NULL)  {
 171                 if (pci_domain_nr(bus) != domain)
 172                         continue;
 173                 tmp_bus = pci_do_find_bus(bus, busnr);
 174                 if (tmp_bus)
 175                         return tmp_bus;
 176         }
 177         return NULL;
 178 }
 179 EXPORT_SYMBOL(pci_find_bus);
 180
 181 /**
 182  * pci_find_next_bus - begin or continue searching for a PCI bus
 183  * @from: Previous PCI bus found, or %NULL for new search.
 184  *
 185  * Iterates through the list of known PCI buses.  A new search is
 186  * initiated by passing %NULL as the @from argument.  Otherwise if
 187  * @from is not %NULL, searches continue from next device on the
 188  * global list.
 189  */
 190 struct pci_bus *pci_find_next_bus(const struct pci_bus *from)
 191 {
 192         struct list_head *n;
 193         struct pci_bus *b = NULL;
 194
 195         WARN_ON(in_interrupt());
 196         down_read(&pci_bus_sem);
 197         n = from ? from->node.next : pci_root_buses.next;
 198         if (n != &pci_root_buses)
 199                 b = list_entry(n, struct pci_bus, node);
 200         up_read(&pci_bus_sem);
 201         return b;
 202 }
 203 EXPORT_SYMBOL(pci_find_next_bus);
 204
 205 /**
 206  * pci_get_slot - locate PCI device for a given PCI slot
 207  * @bus: PCI bus on which desired PCI device resides
 208  * @devfn: encodes number of PCI slot in which the desired PCI
 209  * device resides and the logical device number within that slot
 210  * in case of multi-function devices.
 211  *
 212  * Given a PCI bus and slot/function number, the desired PCI device
 213  * is located in the list of PCI devices.
 214  * If the device is found, its reference count is increased and this
 215  * function returns a pointer to its data structure.  The caller must
 216  * decrement the reference count by calling pci_dev_put().
 217  * If no device is found, %NULL is returned.
 218  */
 219 struct pci_dev *pci_get_slot(struct pci_bus *bus, unsigned int devfn)
 220 {
 221         struct pci_dev *dev;
 222
 223         WARN_ON(in_interrupt());
 224         down_read(&pci_bus_sem);
 225
 226         list_for_each_entry(dev, &bus->devices, bus_list) {
 227                 if (dev->devfn == devfn)
 228                         goto out;
 229         }
 230
 231         dev = NULL;
 232  out:
 233         pci_dev_get(dev);
 234         up_read(&pci_bus_sem);
 235         return dev;
 236 }
 237 EXPORT_SYMBOL(pci_get_slot);
 238
 239 /**
 240  * pci_get_domain_bus_and_slot - locate PCI device for a given PCI domain (segment), bus, and slot
 241  * @domain: PCI domain/segment on which the PCI device resides.
 242  * @bus: PCI bus on which desired PCI device resides
 243  * @devfn: encodes number of PCI slot in which the desired PCI device
 244  * resides and the logical device number within that slot in case of
 245  * multi-function devices.
 246  *
 247  * Given a PCI domain, bus, and slot/function number, the desired PCI
 248  * device is located in the list of PCI devices. If the device is
 249  * found, its reference count is increased and this function returns a
 250  * pointer to its data structure.  The caller must decrement the
 251  * reference count by calling pci_dev_put().  If no device is found,
 252  * %NULL is returned.
 253  */
 254 struct pci_dev *pci_get_domain_bus_and_slot(int domain, unsigned int bus,
 255                                             unsigned int devfn)
 256 {
 257         struct pci_dev *dev = NULL;
 258
 259         for_each_pci_dev(dev) {
 260                 if (pci_domain_nr(dev->bus) == domain &&
 261                     (dev->bus->number == bus && dev->devfn == devfn))
 262                         return dev;
 263         }
 264         return NULL;
 265 }
 266 EXPORT_SYMBOL(pci_get_domain_bus_and_slot);
 267
 268 static int match_pci_dev_by_id(struct device *dev, void *data)
 269 {
 270         struct pci_dev *pdev = to_pci_dev(dev);
 271         struct pci_device_id *id = data;
 272
 273         if (pci_match_one_device(id, pdev))
 274                 return 1;
 275         return 0;
 276 }
 277
 278 /*
 279  * pci_get_dev_by_id - begin or continue searching for a PCI device by id
 280  * @id: pointer to struct pci_device_id to match for the device
 281  * @from: Previous PCI device found in search, or %NULL for new search.
 282  *
 283  * Iterates through the list of known PCI devices.  If a PCI device is found
 284  * with a matching id a pointer to its device structure is returned, and the
 285  * reference count to the device is incremented.  Otherwise, %NULL is returned.
 286  * A new search is initiated by passing %NULL as the @from argument.  Otherwise
 287  * if @from is not %NULL, searches continue from next device on the global
 288  * list.  The reference count for @from is always decremented if it is not
 289  * %NULL.
 290  *
 291  * This is an internal function for use by the other search functions in
 292  * this file.
 293  */
 294 static struct pci_dev *pci_get_dev_by_id(const struct pci_device_id *id,
 295                                          struct pci_dev *from)
 296 {
 297         struct device *dev;
 298         struct device *dev_start = NULL;
 299         struct pci_dev *pdev = NULL;
 300
 301         WARN_ON(in_interrupt());
 302         if (from)
 303                 dev_start = &from->dev;
 304         dev = bus_find_device(&pci_bus_type, dev_start, (void *)id,
 305                               match_pci_dev_by_id);
 306         if (dev)
 307                 pdev = to_pci_dev(dev);
 308         if (from)
 309                 pci_dev_put(from);
 310         return pdev;
 311 }
 312
 313 /**
 314  * pci_get_subsys - begin or continue searching for a PCI device by vendor/subvendor/device/subdevice id
 315  * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
 316  * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
 317  * @ss_vendor: PCI subsystem vendor id to match, or %PCI_ANY_ID to match all vendor ids
 318  * @ss_device: PCI subsystem device id to match, or %PCI_ANY_ID to match all device ids
 319  * @from: Previous PCI device found in search, or %NULL for new search.
 320  *
 321  * Iterates through the list of known PCI devices.  If a PCI device is found
 322  * with a matching @vendor, @device, @ss_vendor and @ss_device, a pointer to its
 323  * device structure is returned, and the reference count to the device is
 324  * incremented.  Otherwise, %NULL is returned.  A new search is initiated by
 325  * passing %NULL as the @from argument.  Otherwise if @from is not %NULL,
 326  * searches continue from next device on the global list.
 327  * The reference count for @from is always decremented if it is not %NULL.
 328  */
 329 struct pci_dev *pci_get_subsys(unsigned int vendor, unsigned int device,
 330                                unsigned int ss_vendor, unsigned int ss_device,
 331                                struct pci_dev *from)
 332 {
 333         struct pci_device_id id = {
 334                 .vendor = vendor,
 335                 .device = device,
 336                 .subvendor = ss_vendor,
 337                 .subdevice = ss_device,
 338         };
 339
 340         return pci_get_dev_by_id(&id, from);
 341 }
 342 EXPORT_SYMBOL(pci_get_subsys);
 343
 344 /**
 345  * pci_get_device - begin or continue searching for a PCI device by vendor/device id
 346  * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
 347  * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
 348  * @from: Previous PCI device found in search, or %NULL for new search.
 349  *
 350  * Iterates through the list of known PCI devices.  If a PCI device is
 351  * found with a matching @vendor and @device, the reference count to the
 352  * device is incremented and a pointer to its device structure is returned.
 353  * Otherwise, %NULL is returned.  A new search is initiated by passing %NULL
 354  * as the @from argument.  Otherwise if @from is not %NULL, searches continue
 355  * from next device on the global list.  The reference count for @from is
 356  * always decremented if it is not %NULL.
 357  */
 358 struct pci_dev *pci_get_device(unsigned int vendor, unsigned int device,
 359                                struct pci_dev *from)
 360 {
 361         return pci_get_subsys(vendor, device, PCI_ANY_ID, PCI_ANY_ID, from);
 362 }
 363 EXPORT_SYMBOL(pci_get_device);
 364
 365 /**
 366  * pci_get_class - begin or continue searching for a PCI device by class
 367  * @class: search for a PCI device with this class designation
 368  * @from: Previous PCI device found in search, or %NULL for new search.
 369  *
 370  * Iterates through the list of known PCI devices.  If a PCI device is
 371  * found with a matching @class, the reference count to the device is
 372  * incremented and a pointer to its device structure is returned.
 373  * Otherwise, %NULL is returned.
 374  * A new search is initiated by passing %NULL as the @from argument.
 375  * Otherwise if @from is not %NULL, searches continue from next device
 376  * on the global list.  The reference count for @from is always decremented
 377  * if it is not %NULL.
 378  */
 379 struct pci_dev *pci_get_class(unsigned int class, struct pci_dev *from)
 380 {
 381         struct pci_device_id id = {
 382                 .vendor = PCI_ANY_ID,
 383                 .device = PCI_ANY_ID,
 384                 .subvendor = PCI_ANY_ID,
 385                 .subdevice = PCI_ANY_ID,
 386                 .class_mask = PCI_ANY_ID,
 387                 .class = class,
 388         };
 389
 390         return pci_get_dev_by_id(&id, from);
 391 }
 392 EXPORT_SYMBOL(pci_get_class);
 393
 394 /**
 395  * pci_dev_present - Returns 1 if device matching the device list is present, 0 if not.
 396  * @ids: A pointer to a null terminated list of struct pci_device_id structures
 397  * that describe the type of PCI device the caller is trying to find.
 398  *
 399  * Obvious fact: You do not have a reference to any device that might be found
 400  * by this function, so if that device is removed from the system right after
 401  * this function is finished, the value will be stale.  Use this function to
 402  * find devices that are usually built into a system, or for a general hint as
 403  * to if another device happens to be present at this specific moment in time.
 404  */
 405 int pci_dev_present(const struct pci_device_id *ids)
 406 {
 407         struct pci_dev *found = NULL;
 408
 409         WARN_ON(in_interrupt());
 410         while (ids->vendor || ids->subvendor || ids->class_mask) {
 411                 found = pci_get_dev_by_id(ids, NULL);
 412                 if (found) {
 413                         pci_dev_put(found);
 414                         return 1;
 415                 }
 416                 ids++;
 417         }
 418
 419         return 0;
 420 }
 421 EXPORT_SYMBOL(pci_dev_present);