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 (pci_is_pcie(pdev))
  30                 return NULL;
  31         while (1) {
  32                 if (pci_is_root_bus(pdev->bus))
  33                         break;
  34                 pdev = pdev->bus->self;
  35                 /* a p2p bridge */
  36                 if (!pci_is_pcie(pdev)) {
  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 /**
 117  * pci_get_slot - locate PCI device for a given PCI slot
 118  * @bus: PCI bus on which desired PCI device resides
 119  * @devfn: encodes number of PCI slot in which the desired PCI
 120  * device resides and the logical device number within that slot
 121  * in case of multi-function devices.
 122  *
 123  * Given a PCI bus and slot/function number, the desired PCI device
 124  * is located in the list of PCI devices.
 125  * If the device is found, its reference count is increased and this
 126  * function returns a pointer to its data structure.  The caller must
 127  * decrement the reference count by calling pci_dev_put().
 128  * If no device is found, %NULL is returned.
 129  */
 130 struct pci_dev * pci_get_slot(struct pci_bus *bus, unsigned int devfn)
 131 {
 132         struct list_head *tmp;
 133         struct pci_dev *dev;
 134
 135         WARN_ON(in_interrupt());
 136         down_read(&pci_bus_sem);
 137
 138         list_for_each(tmp, &bus->devices) {
 139                 dev = pci_dev_b(tmp);
 140                 if (dev->devfn == devfn)
 141                         goto out;
 142         }
 143
 144         dev = NULL;
 145  out:
 146         pci_dev_get(dev);
 147         up_read(&pci_bus_sem);
 148         return dev;
 149 }
 150
 151 /**
 152  * pci_get_domain_bus_and_slot - locate PCI device for a given PCI domain (segment), bus, and slot
 153  * @domain: PCI domain/segment on which the PCI device resides.
 154  * @bus: PCI bus on which desired PCI device resides
 155  * @devfn: encodes number of PCI slot in which the desired PCI device
 156  * resides and the logical device number within that slot in case of
 157  * multi-function devices.
 158  *
 159  * Given a PCI domain, bus, and slot/function number, the desired PCI
 160  * device is located in the list of PCI devices. If the device is
 161  * found, its reference count is increased and this function returns a
 162  * pointer to its data structure.  The caller must decrement the
 163  * reference count by calling pci_dev_put().  If no device is found,
 164  * %NULL is returned.
 165  */
 166 struct pci_dev *pci_get_domain_bus_and_slot(int domain, unsigned int bus,
 167                                             unsigned int devfn)
 168 {
 169         struct pci_dev *dev = NULL;
 170
 171         while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) {
 172                 if (pci_domain_nr(dev->bus) == domain &&
 173                     (dev->bus->number == bus && dev->devfn == devfn))
 174                         return dev;
 175         }
 176         return NULL;
 177 }
 178 EXPORT_SYMBOL(pci_get_domain_bus_and_slot);
 179
 180 static int match_pci_dev_by_id(struct device *dev, void *data)
 181 {
 182         struct pci_dev *pdev = to_pci_dev(dev);
 183         struct pci_device_id *id = data;
 184
 185         if (pci_match_one_device(id, pdev))
 186                 return 1;
 187         return 0;
 188 }
 189
 190 /*
 191  * pci_get_dev_by_id - begin or continue searching for a PCI device by id
 192  * @id: pointer to struct pci_device_id to match for the device
 193  * @from: Previous PCI device found in search, or %NULL for new search.
 194  *
 195  * Iterates through the list of known PCI devices.  If a PCI device is found
 196  * with a matching id a pointer to its device structure is returned, and the
 197  * reference count to the device is incremented.  Otherwise, %NULL is returned.
 198  * A new search is initiated by passing %NULL as the @from argument.  Otherwise
 199  * if @from is not %NULL, searches continue from next device on the global
 200  * list.  The reference count for @from is always decremented if it is not
 201  * %NULL.
 202  *
 203  * This is an internal function for use by the other search functions in
 204  * this file.
 205  */
 206 static struct pci_dev *pci_get_dev_by_id(const struct pci_device_id *id,
 207                                          struct pci_dev *from)
 208 {
 209         struct device *dev;
 210         struct device *dev_start = NULL;
 211         struct pci_dev *pdev = NULL;
 212
 213         WARN_ON(in_interrupt());
 214         if (from)
 215                 dev_start = &from->dev;
 216         dev = bus_find_device(&pci_bus_type, dev_start, (void *)id,
 217                               match_pci_dev_by_id);
 218         if (dev)
 219                 pdev = to_pci_dev(dev);
 220         if (from)
 221                 pci_dev_put(from);
 222         return pdev;
 223 }
 224
 225 /**
 226  * pci_get_subsys - begin or continue searching for a PCI device by vendor/subvendor/device/subdevice id
 227  * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
 228  * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
 229  * @ss_vendor: PCI subsystem vendor id to match, or %PCI_ANY_ID to match all vendor ids
 230  * @ss_device: PCI subsystem device id to match, or %PCI_ANY_ID to match all device ids
 231  * @from: Previous PCI device found in search, or %NULL for new search.
 232  *
 233  * Iterates through the list of known PCI devices.  If a PCI device is found
 234  * with a matching @vendor, @device, @ss_vendor and @ss_device, a pointer to its
 235  * device structure is returned, and the reference count to the device is
 236  * incremented.  Otherwise, %NULL is returned.  A new search is initiated by
 237  * passing %NULL as the @from argument.  Otherwise if @from is not %NULL,
 238  * searches continue from next device on the global list.
 239  * The reference count for @from is always decremented if it is not %NULL.
 240  */
 241 struct pci_dev *pci_get_subsys(unsigned int vendor, unsigned int device,
 242                                unsigned int ss_vendor, unsigned int ss_device,
 243                                struct pci_dev *from)
 244 {
 245         struct pci_dev *pdev;
 246         struct pci_device_id *id;
 247
 248         /*
 249          * pci_find_subsys() can be called on the ide_setup() path,
 250          * super-early in boot.  But the down_read() will enable local
 251          * interrupts, which can cause some machines to crash.  So here we
 252          * detect and flag that situation and bail out early.
 253          */
 254         if (unlikely(no_pci_devices()))
 255                 return NULL;
 256
 257         id = kzalloc(sizeof(*id), GFP_KERNEL);
 258         if (!id)
 259                 return NULL;
 260         id->vendor = vendor;
 261         id->device = device;
 262         id->subvendor = ss_vendor;
 263         id->subdevice = ss_device;
 264
 265         pdev = pci_get_dev_by_id(id, from);
 266         kfree(id);
 267
 268         return pdev;
 269 }
 270
 271 /**
 272  * pci_get_device - begin or continue searching for a PCI device by vendor/device id
 273  * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
 274  * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
 275  * @from: Previous PCI device found in search, or %NULL for new search.
 276  *
 277  * Iterates through the list of known PCI devices.  If a PCI device is
 278  * found with a matching @vendor and @device, the reference count to the
 279  * device is incremented and a pointer to its device structure is returned.
 280  * Otherwise, %NULL is returned.  A new search is initiated by passing %NULL
 281  * as the @from argument.  Otherwise if @from is not %NULL, searches continue
 282  * from next device on the global list.  The reference count for @from is
 283  * always decremented if it is not %NULL.
 284  */
 285 struct pci_dev *
 286 pci_get_device(unsigned int vendor, unsigned int device, struct pci_dev *from)
 287 {
 288         return pci_get_subsys(vendor, device, PCI_ANY_ID, PCI_ANY_ID, from);
 289 }
 290
 291 /**
 292  * pci_get_class - begin or continue searching for a PCI device by class
 293  * @class: search for a PCI device with this class designation
 294  * @from: Previous PCI device found in search, or %NULL for new search.
 295  *
 296  * Iterates through the list of known PCI devices.  If a PCI device is
 297  * found with a matching @class, the reference count to the device is
 298  * incremented and a pointer to its device structure is returned.
 299  * Otherwise, %NULL is returned.
 300  * A new search is initiated by passing %NULL as the @from argument.
 301  * Otherwise if @from is not %NULL, searches continue from next device
 302  * on the global list.  The reference count for @from is always decremented
 303  * if it is not %NULL.
 304  */
 305 struct pci_dev *pci_get_class(unsigned int class, struct pci_dev *from)
 306 {
 307         struct pci_dev *dev;
 308         struct pci_device_id *id;
 309
 310         id = kzalloc(sizeof(*id), GFP_KERNEL);
 311         if (!id)
 312                 return NULL;
 313         id->vendor = id->device = id->subvendor = id->subdevice = PCI_ANY_ID;
 314         id->class_mask = PCI_ANY_ID;
 315         id->class = class;
 316
 317         dev = pci_get_dev_by_id(id, from);
 318         kfree(id);
 319         return dev;
 320 }
 321
 322 /**
 323  * pci_dev_present - Returns 1 if device matching the device list is present, 0 if not.
 324  * @ids: A pointer to a null terminated list of struct pci_device_id structures
 325  * that describe the type of PCI device the caller is trying to find.
 326  *
 327  * Obvious fact: You do not have a reference to any device that might be found
 328  * by this function, so if that device is removed from the system right after
 329  * this function is finished, the value will be stale.  Use this function to
 330  * find devices that are usually built into a system, or for a general hint as
 331  * to if another device happens to be present at this specific moment in time.
 332  */
 333 int pci_dev_present(const struct pci_device_id *ids)
 334 {
 335         struct pci_dev *found = NULL;
 336
 337         WARN_ON(in_interrupt());
 338         while (ids->vendor || ids->subvendor || ids->class_mask) {
 339                 found = pci_get_dev_by_id(ids, NULL);
 340                 if (found)
 341                         goto exit;
 342                 ids++;
 343         }
 344 exit:
 345         if (found)
 346                 return 1;
 347         return 0;
 348 }
 349 EXPORT_SYMBOL(pci_dev_present);
 350
 351 /* For boot time work */
 352 EXPORT_SYMBOL(pci_find_bus);
 353 EXPORT_SYMBOL(pci_find_next_bus);
 354 /* For everyone */
 355 EXPORT_SYMBOL(pci_get_device);
 356 EXPORT_SYMBOL(pci_get_subsys);
 357 EXPORT_SYMBOL(pci_get_slot);
 358 EXPORT_SYMBOL(pci_get_class);