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 static struct pci_bus *pci_do_find_bus(struct pci_bus *bus, unsigned char busnr)
 107 {
 108         struct pci_bus *child;
 109         struct pci_bus *tmp;
 110
 111         if (bus->number == busnr)
 112                 return bus;
 113
 114         list_for_each_entry(tmp, &bus->children, node) {
 115                 child = pci_do_find_bus(tmp, busnr);
 116                 if (child)
 117                         return child;
 118         }
 119         return NULL;
 120 }
 121
 122 /**
 123  * pci_find_bus - locate PCI bus from a given domain and bus number
 124  * @domain: number of PCI domain to search
 125  * @busnr: number of desired PCI bus
 126  *
 127  * Given a PCI bus number and domain number, the desired PCI bus is located
 128  * in the global list of PCI buses.  If the bus is found, a pointer to its
 129  * data structure is returned.  If no bus is found, %NULL is returned.
 130  */
 131 struct pci_bus *pci_find_bus(int domain, int busnr)
 132 {
 133         struct pci_bus *bus = NULL;
 134         struct pci_bus *tmp_bus;
 135
 136         while ((bus = pci_find_next_bus(bus)) != NULL)  {
 137                 if (pci_domain_nr(bus) != domain)
 138                         continue;
 139                 tmp_bus = pci_do_find_bus(bus, busnr);
 140                 if (tmp_bus)
 141                         return tmp_bus;
 142         }
 143         return NULL;
 144 }
 145 EXPORT_SYMBOL(pci_find_bus);
 146
 147 /**
 148  * pci_find_next_bus - begin or continue searching for a PCI bus
 149  * @from: Previous PCI bus found, or %NULL for new search.
 150  *
 151  * Iterates through the list of known PCI buses.  A new search is
 152  * initiated by passing %NULL as the @from argument.  Otherwise if
 153  * @from is not %NULL, searches continue from next device on the
 154  * global list.
 155  */
 156 struct pci_bus *pci_find_next_bus(const struct pci_bus *from)
 157 {
 158         struct list_head *n;
 159         struct pci_bus *b = NULL;
 160
 161         WARN_ON(in_interrupt());
 162         down_read(&pci_bus_sem);
 163         n = from ? from->node.next : pci_root_buses.next;
 164         if (n != &pci_root_buses)
 165                 b = list_entry(n, struct pci_bus, node);
 166         up_read(&pci_bus_sem);
 167         return b;
 168 }
 169 EXPORT_SYMBOL(pci_find_next_bus);
 170
 171 /**
 172  * pci_get_slot - locate PCI device for a given PCI slot
 173  * @bus: PCI bus on which desired PCI device resides
 174  * @devfn: encodes number of PCI slot in which the desired PCI
 175  * device resides and the logical device number within that slot
 176  * in case of multi-function devices.
 177  *
 178  * Given a PCI bus and slot/function number, the desired PCI device
 179  * is located in the list of PCI devices.
 180  * If the device is found, its reference count is increased and this
 181  * function returns a pointer to its data structure.  The caller must
 182  * decrement the reference count by calling pci_dev_put().
 183  * If no device is found, %NULL is returned.
 184  */
 185 struct pci_dev *pci_get_slot(struct pci_bus *bus, unsigned int devfn)
 186 {
 187         struct pci_dev *dev;
 188
 189         WARN_ON(in_interrupt());
 190         down_read(&pci_bus_sem);
 191
 192         list_for_each_entry(dev, &bus->devices, bus_list) {
 193                 if (dev->devfn == devfn)
 194                         goto out;
 195         }
 196
 197         dev = NULL;
 198  out:
 199         pci_dev_get(dev);
 200         up_read(&pci_bus_sem);
 201         return dev;
 202 }
 203 EXPORT_SYMBOL(pci_get_slot);
 204
 205 /**
 206  * pci_get_domain_bus_and_slot - locate PCI device for a given PCI domain (segment), bus, and slot
 207  * @domain: PCI domain/segment on which the PCI device resides.
 208  * @bus: PCI bus on which desired PCI device resides
 209  * @devfn: encodes number of PCI slot in which the desired PCI device
 210  * resides and the logical device number within that slot in case of
 211  * multi-function devices.
 212  *
 213  * Given a PCI domain, bus, and slot/function number, the desired PCI
 214  * device is located in the list of PCI devices. If the device is
 215  * found, its reference count is increased and this function returns a
 216  * pointer to its data structure.  The caller must decrement the
 217  * reference count by calling pci_dev_put().  If no device is found,
 218  * %NULL is returned.
 219  */
 220 struct pci_dev *pci_get_domain_bus_and_slot(int domain, unsigned int bus,
 221                                             unsigned int devfn)
 222 {
 223         struct pci_dev *dev = NULL;
 224
 225         for_each_pci_dev(dev) {
 226                 if (pci_domain_nr(dev->bus) == domain &&
 227                     (dev->bus->number == bus && dev->devfn == devfn))
 228                         return dev;
 229         }
 230         return NULL;
 231 }
 232 EXPORT_SYMBOL(pci_get_domain_bus_and_slot);
 233
 234 static int match_pci_dev_by_id(struct device *dev, void *data)
 235 {
 236         struct pci_dev *pdev = to_pci_dev(dev);
 237         struct pci_device_id *id = data;
 238
 239         if (pci_match_one_device(id, pdev))
 240                 return 1;
 241         return 0;
 242 }
 243
 244 /*
 245  * pci_get_dev_by_id - begin or continue searching for a PCI device by id
 246  * @id: pointer to struct pci_device_id to match for the device
 247  * @from: Previous PCI device found in search, or %NULL for new search.
 248  *
 249  * Iterates through the list of known PCI devices.  If a PCI device is found
 250  * with a matching id a pointer to its device structure is returned, and the
 251  * reference count to the device is incremented.  Otherwise, %NULL is returned.
 252  * A new search is initiated by passing %NULL as the @from argument.  Otherwise
 253  * if @from is not %NULL, searches continue from next device on the global
 254  * list.  The reference count for @from is always decremented if it is not
 255  * %NULL.
 256  *
 257  * This is an internal function for use by the other search functions in
 258  * this file.
 259  */
 260 static struct pci_dev *pci_get_dev_by_id(const struct pci_device_id *id,
 261                                          struct pci_dev *from)
 262 {
 263         struct device *dev;
 264         struct device *dev_start = NULL;
 265         struct pci_dev *pdev = NULL;
 266
 267         WARN_ON(in_interrupt());
 268         if (from)
 269                 dev_start = &from->dev;
 270         dev = bus_find_device(&pci_bus_type, dev_start, (void *)id,
 271                               match_pci_dev_by_id);
 272         if (dev)
 273                 pdev = to_pci_dev(dev);
 274         if (from)
 275                 pci_dev_put(from);
 276         return pdev;
 277 }
 278
 279 /**
 280  * pci_get_subsys - begin or continue searching for a PCI device by vendor/subvendor/device/subdevice id
 281  * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
 282  * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
 283  * @ss_vendor: PCI subsystem vendor id to match, or %PCI_ANY_ID to match all vendor ids
 284  * @ss_device: PCI subsystem device id to match, or %PCI_ANY_ID to match all device ids
 285  * @from: Previous PCI device found in search, or %NULL for new search.
 286  *
 287  * Iterates through the list of known PCI devices.  If a PCI device is found
 288  * with a matching @vendor, @device, @ss_vendor and @ss_device, a pointer to its
 289  * device structure is returned, and the reference count to the device is
 290  * incremented.  Otherwise, %NULL is returned.  A new search is initiated by
 291  * passing %NULL as the @from argument.  Otherwise if @from is not %NULL,
 292  * searches continue from next device on the global list.
 293  * The reference count for @from is always decremented if it is not %NULL.
 294  */
 295 struct pci_dev *pci_get_subsys(unsigned int vendor, unsigned int device,
 296                                unsigned int ss_vendor, unsigned int ss_device,
 297                                struct pci_dev *from)
 298 {
 299         struct pci_device_id id = {
 300                 .vendor = vendor,
 301                 .device = device,
 302                 .subvendor = ss_vendor,
 303                 .subdevice = ss_device,
 304         };
 305
 306         return pci_get_dev_by_id(&id, from);
 307 }
 308 EXPORT_SYMBOL(pci_get_subsys);
 309
 310 /**
 311  * pci_get_device - begin or continue searching for a PCI device by vendor/device id
 312  * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
 313  * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
 314  * @from: Previous PCI device found in search, or %NULL for new search.
 315  *
 316  * Iterates through the list of known PCI devices.  If a PCI device is
 317  * found with a matching @vendor and @device, the reference count to the
 318  * device is incremented and a pointer to its device structure is returned.
 319  * Otherwise, %NULL is returned.  A new search is initiated by passing %NULL
 320  * as the @from argument.  Otherwise if @from is not %NULL, searches continue
 321  * from next device on the global list.  The reference count for @from is
 322  * always decremented if it is not %NULL.
 323  */
 324 struct pci_dev *pci_get_device(unsigned int vendor, unsigned int device,
 325                                struct pci_dev *from)
 326 {
 327         return pci_get_subsys(vendor, device, PCI_ANY_ID, PCI_ANY_ID, from);
 328 }
 329 EXPORT_SYMBOL(pci_get_device);
 330
 331 /**
 332  * pci_get_class - begin or continue searching for a PCI device by class
 333  * @class: search for a PCI device with this class designation
 334  * @from: Previous PCI device found in search, or %NULL for new search.
 335  *
 336  * Iterates through the list of known PCI devices.  If a PCI device is
 337  * found with a matching @class, the reference count to the device is
 338  * incremented and a pointer to its device structure is returned.
 339  * Otherwise, %NULL is returned.
 340  * A new search is initiated by passing %NULL as the @from argument.
 341  * Otherwise if @from is not %NULL, searches continue from next device
 342  * on the global list.  The reference count for @from is always decremented
 343  * if it is not %NULL.
 344  */
 345 struct pci_dev *pci_get_class(unsigned int class, struct pci_dev *from)
 346 {
 347         struct pci_device_id id = {
 348                 .vendor = PCI_ANY_ID,
 349                 .device = PCI_ANY_ID,
 350                 .subvendor = PCI_ANY_ID,
 351                 .subdevice = PCI_ANY_ID,
 352                 .class_mask = PCI_ANY_ID,
 353                 .class = class,
 354         };
 355
 356         return pci_get_dev_by_id(&id, from);
 357 }
 358 EXPORT_SYMBOL(pci_get_class);
 359
 360 /**
 361  * pci_dev_present - Returns 1 if device matching the device list is present, 0 if not.
 362  * @ids: A pointer to a null terminated list of struct pci_device_id structures
 363  * that describe the type of PCI device the caller is trying to find.
 364  *
 365  * Obvious fact: You do not have a reference to any device that might be found
 366  * by this function, so if that device is removed from the system right after
 367  * this function is finished, the value will be stale.  Use this function to
 368  * find devices that are usually built into a system, or for a general hint as
 369  * to if another device happens to be present at this specific moment in time.
 370  */
 371 int pci_dev_present(const struct pci_device_id *ids)
 372 {
 373         struct pci_dev *found = NULL;
 374
 375         WARN_ON(in_interrupt());
 376         while (ids->vendor || ids->subvendor || ids->class_mask) {
 377                 found = pci_get_dev_by_id(ids, NULL);
 378                 if (found) {
 379                         pci_dev_put(found);
 380                         return 1;
 381                 }
 382                 ids++;
 383         }
 384
 385         return 0;
 386 }
 387 EXPORT_SYMBOL(pci_dev_present);