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->dma_alias_mask)) {
  44                 u8 devfn;
  45
  46                 for_each_set_bit(devfn, pdev->dma_alias_mask, U8_MAX) {
  47                         ret = fn(pdev, PCI_DEVID(pdev->bus->number, devfn),
  48                                  data);
  49                         if (ret)
  50                                 return ret;
  51                 }
  52         }
  53
  54         for (bus = pdev->bus; !pci_is_root_bus(bus); bus = bus->parent) {
  55                 struct pci_dev *tmp;
  56
  57                 /* Skip virtual buses */
  58                 if (!bus->self)
  59                         continue;
  60
  61                 tmp = bus->self;
  62
  63                 /* stop at bridge where translation unit is associated */
  64                 if (tmp->dev_flags & PCI_DEV_FLAGS_BRIDGE_XLATE_ROOT)
  65                         return ret;
  66
  67                 /*
  68                  * PCIe-to-PCI/X bridges alias transactions from downstream
  69                  * devices using the subordinate bus number (PCI Express to
  70                  * PCI/PCI-X Bridge Spec, rev 1.0, sec 2.3).  For all cases
  71                  * where the upstream bus is PCI/X we alias to the bridge
  72                  * (there are various conditions in the previous reference
  73                  * where the bridge may take ownership of transactions, even
  74                  * when the secondary interface is PCI-X).
  75                  */
  76                 if (pci_is_pcie(tmp)) {
  77                         switch (pci_pcie_type(tmp)) {
  78                         case PCI_EXP_TYPE_ROOT_PORT:
  79                         case PCI_EXP_TYPE_UPSTREAM:
  80                         case PCI_EXP_TYPE_DOWNSTREAM:
  81                                 continue;
  82                         case PCI_EXP_TYPE_PCI_BRIDGE:
  83                                 ret = fn(tmp,
  84                                          PCI_DEVID(tmp->subordinate->number,
  85                                                    PCI_DEVFN(0, 0)), data);
  86                                 if (ret)
  87                                         return ret;
  88                                 continue;
  89                         case PCI_EXP_TYPE_PCIE_BRIDGE:
  90                                 ret = fn(tmp,
  91                                          PCI_DEVID(tmp->bus->number,
  92                                                    tmp->devfn), data);
  93                                 if (ret)
  94                                         return ret;
  95                                 continue;
  96                         }
  97                 } else {
  98                         if (tmp->dev_flags & PCI_DEV_FLAG_PCIE_BRIDGE_ALIAS)
  99                                 ret = fn(tmp,
 100                                          PCI_DEVID(tmp->subordinate->number,
 101                                                    PCI_DEVFN(0, 0)), data);
 102                         else
 103                                 ret = fn(tmp,
 104                                          PCI_DEVID(tmp->bus->number,
 105                                                    tmp->devfn), data);
 106                         if (ret)
 107                                 return ret;
 108                 }
 109         }
 110
 111         return ret;
 112 }
 113
 114 static struct pci_bus *pci_do_find_bus(struct pci_bus *bus, unsigned char busnr)
 115 {
 116         struct pci_bus *child;
 117         struct pci_bus *tmp;
 118
 119         if (bus->number == busnr)
 120                 return bus;
 121
 122         list_for_each_entry(tmp, &bus->children, node) {
 123                 child = pci_do_find_bus(tmp, busnr);
 124                 if (child)
 125                         return child;
 126         }
 127         return NULL;
 128 }
 129
 130 /**
 131  * pci_find_bus - locate PCI bus from a given domain and bus number
 132  * @domain: number of PCI domain to search
 133  * @busnr: number of desired PCI bus
 134  *
 135  * Given a PCI bus number and domain number, the desired PCI bus is located
 136  * in the global list of PCI buses.  If the bus is found, a pointer to its
 137  * data structure is returned.  If no bus is found, %NULL is returned.
 138  */
 139 struct pci_bus *pci_find_bus(int domain, int busnr)
 140 {
 141         struct pci_bus *bus = NULL;
 142         struct pci_bus *tmp_bus;
 143
 144         while ((bus = pci_find_next_bus(bus)) != NULL)  {
 145                 if (pci_domain_nr(bus) != domain)
 146                         continue;
 147                 tmp_bus = pci_do_find_bus(bus, busnr);
 148                 if (tmp_bus)
 149                         return tmp_bus;
 150         }
 151         return NULL;
 152 }
 153 EXPORT_SYMBOL(pci_find_bus);
 154
 155 /**
 156  * pci_find_next_bus - begin or continue searching for a PCI bus
 157  * @from: Previous PCI bus found, or %NULL for new search.
 158  *
 159  * Iterates through the list of known PCI buses.  A new search is
 160  * initiated by passing %NULL as the @from argument.  Otherwise if
 161  * @from is not %NULL, searches continue from next device on the
 162  * global list.
 163  */
 164 struct pci_bus *pci_find_next_bus(const struct pci_bus *from)
 165 {
 166         struct list_head *n;
 167         struct pci_bus *b = NULL;
 168
 169         WARN_ON(in_interrupt());
 170         down_read(&pci_bus_sem);
 171         n = from ? from->node.next : pci_root_buses.next;
 172         if (n != &pci_root_buses)
 173                 b = list_entry(n, struct pci_bus, node);
 174         up_read(&pci_bus_sem);
 175         return b;
 176 }
 177 EXPORT_SYMBOL(pci_find_next_bus);
 178
 179 /**
 180  * pci_get_slot - locate PCI device for a given PCI slot
 181  * @bus: PCI bus on which desired PCI device resides
 182  * @devfn: encodes number of PCI slot in which the desired PCI
 183  * device resides and the logical device number within that slot
 184  * in case of multi-function devices.
 185  *
 186  * Given a PCI bus and slot/function number, the desired PCI device
 187  * is located in the list of PCI devices.
 188  * If the device is found, its reference count is increased and this
 189  * function returns a pointer to its data structure.  The caller must
 190  * decrement the reference count by calling pci_dev_put().
 191  * If no device is found, %NULL is returned.
 192  */
 193 struct pci_dev *pci_get_slot(struct pci_bus *bus, unsigned int devfn)
 194 {
 195         struct pci_dev *dev;
 196
 197         WARN_ON(in_interrupt());
 198         down_read(&pci_bus_sem);
 199
 200         list_for_each_entry(dev, &bus->devices, bus_list) {
 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 EXPORT_SYMBOL(pci_get_slot);
 212
 213 /**
 214  * pci_get_domain_bus_and_slot - locate PCI device for a given PCI domain (segment), bus, and slot
 215  * @domain: PCI domain/segment on which the PCI device resides.
 216  * @bus: PCI bus on which desired PCI device resides
 217  * @devfn: encodes number of PCI slot in which the desired PCI device
 218  * resides and the logical device number within that slot in case of
 219  * multi-function devices.
 220  *
 221  * Given a PCI domain, bus, and slot/function number, the desired PCI
 222  * device is located in the list of PCI devices. If the device is
 223  * found, its reference count is increased and this function returns a
 224  * pointer to its data structure.  The caller must decrement the
 225  * reference count by calling pci_dev_put().  If no device is found,
 226  * %NULL is returned.
 227  */
 228 struct pci_dev *pci_get_domain_bus_and_slot(int domain, unsigned int bus,
 229                                             unsigned int devfn)
 230 {
 231         struct pci_dev *dev = NULL;
 232
 233         for_each_pci_dev(dev) {
 234                 if (pci_domain_nr(dev->bus) == domain &&
 235                     (dev->bus->number == bus && dev->devfn == devfn))
 236                         return dev;
 237         }
 238         return NULL;
 239 }
 240 EXPORT_SYMBOL(pci_get_domain_bus_and_slot);
 241
 242 static int match_pci_dev_by_id(struct device *dev, void *data)
 243 {
 244         struct pci_dev *pdev = to_pci_dev(dev);
 245         struct pci_device_id *id = data;
 246
 247         if (pci_match_one_device(id, pdev))
 248                 return 1;
 249         return 0;
 250 }
 251
 252 /*
 253  * pci_get_dev_by_id - begin or continue searching for a PCI device by id
 254  * @id: pointer to struct pci_device_id to match for the device
 255  * @from: Previous PCI device found in search, or %NULL for new search.
 256  *
 257  * Iterates through the list of known PCI devices.  If a PCI device is found
 258  * with a matching id a pointer to its device structure is returned, and the
 259  * reference count to the device is incremented.  Otherwise, %NULL is returned.
 260  * A new search is initiated by passing %NULL as the @from argument.  Otherwise
 261  * if @from is not %NULL, searches continue from next device on the global
 262  * list.  The reference count for @from is always decremented if it is not
 263  * %NULL.
 264  *
 265  * This is an internal function for use by the other search functions in
 266  * this file.
 267  */
 268 static struct pci_dev *pci_get_dev_by_id(const struct pci_device_id *id,
 269                                          struct pci_dev *from)
 270 {
 271         struct device *dev;
 272         struct device *dev_start = NULL;
 273         struct pci_dev *pdev = NULL;
 274
 275         WARN_ON(in_interrupt());
 276         if (from)
 277                 dev_start = &from->dev;
 278         dev = bus_find_device(&pci_bus_type, dev_start, (void *)id,
 279                               match_pci_dev_by_id);
 280         if (dev)
 281                 pdev = to_pci_dev(dev);
 282         pci_dev_put(from);
 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                                struct pci_dev *from)
 305 {
 306         struct pci_device_id id = {
 307                 .vendor = vendor,
 308                 .device = device,
 309                 .subvendor = ss_vendor,
 310                 .subdevice = ss_device,
 311         };
 312
 313         return pci_get_dev_by_id(&id, from);
 314 }
 315 EXPORT_SYMBOL(pci_get_subsys);
 316
 317 /**
 318  * pci_get_device - begin or continue searching for a PCI device by vendor/device id
 319  * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
 320  * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
 321  * @from: Previous PCI device found in search, or %NULL for new search.
 322  *
 323  * Iterates through the list of known PCI devices.  If a PCI device is
 324  * found with a matching @vendor and @device, the reference count to the
 325  * device is incremented and a pointer to its device structure is returned.
 326  * Otherwise, %NULL is returned.  A new search is initiated by passing %NULL
 327  * as the @from argument.  Otherwise if @from is not %NULL, searches continue
 328  * from next device on the global list.  The reference count for @from is
 329  * always decremented if it is not %NULL.
 330  */
 331 struct pci_dev *pci_get_device(unsigned int vendor, unsigned int device,
 332                                struct pci_dev *from)
 333 {
 334         return pci_get_subsys(vendor, device, PCI_ANY_ID, PCI_ANY_ID, from);
 335 }
 336 EXPORT_SYMBOL(pci_get_device);
 337
 338 /**
 339  * pci_get_class - begin or continue searching for a PCI device by class
 340  * @class: search for a PCI device with this class designation
 341  * @from: Previous PCI device found in search, or %NULL for new search.
 342  *
 343  * Iterates through the list of known PCI devices.  If a PCI device is
 344  * found with a matching @class, the reference count to the device is
 345  * incremented and a pointer to its device structure is returned.
 346  * Otherwise, %NULL is returned.
 347  * A new search is initiated by passing %NULL as the @from argument.
 348  * Otherwise if @from is not %NULL, searches continue from next device
 349  * on the global list.  The reference count for @from is always decremented
 350  * if it is not %NULL.
 351  */
 352 struct pci_dev *pci_get_class(unsigned int class, struct pci_dev *from)
 353 {
 354         struct pci_device_id id = {
 355                 .vendor = PCI_ANY_ID,
 356                 .device = PCI_ANY_ID,
 357                 .subvendor = PCI_ANY_ID,
 358                 .subdevice = PCI_ANY_ID,
 359                 .class_mask = PCI_ANY_ID,
 360                 .class = class,
 361         };
 362
 363         return pci_get_dev_by_id(&id, from);
 364 }
 365 EXPORT_SYMBOL(pci_get_class);
 366
 367 /**
 368  * pci_dev_present - Returns 1 if device matching the device list is present, 0 if not.
 369  * @ids: A pointer to a null terminated list of struct pci_device_id structures
 370  * that describe the type of PCI device the caller is trying to find.
 371  *
 372  * Obvious fact: You do not have a reference to any device that might be found
 373  * by this function, so if that device is removed from the system right after
 374  * this function is finished, the value will be stale.  Use this function to
 375  * find devices that are usually built into a system, or for a general hint as
 376  * to if another device happens to be present at this specific moment in time.
 377  */
 378 int pci_dev_present(const struct pci_device_id *ids)
 379 {
 380         struct pci_dev *found = NULL;
 381
 382         WARN_ON(in_interrupt());
 383         while (ids->vendor || ids->subvendor || ids->class_mask) {
 384                 found = pci_get_dev_by_id(ids, NULL);
 385                 if (found) {
 386                         pci_dev_put(found);
 387                         return 1;
 388                 }
 389                 ids++;
 390         }
 391
 392         return 0;
 393 }
 394 EXPORT_SYMBOL(pci_dev_present);