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/slab.h>
  13 #include <linux/module.h>
  14 #include <linux/interrupt.h>
  15 #include "pci.h"
  16
  17 DECLARE_RWSEM(pci_bus_sem);
  18 EXPORT_SYMBOL_GPL(pci_bus_sem);
  19
  20 /*
  21  * find the upstream PCIe-to-PCI bridge of a PCI device
  22  * if the device is PCIE, return NULL
  23  * if the device isn't connected to a PCIe bridge (that is its parent is a
  24  * legacy PCI bridge and the bridge is directly connected to bus 0), return its
  25  * parent
  26  */
  27 struct pci_dev *
  28 pci_find_upstream_pcie_bridge(struct pci_dev *pdev)
  29 {
  30         struct pci_dev *tmp = NULL;
  31
  32         if (pci_is_pcie(pdev))
  33                 return NULL;
  34         while (1) {
  35                 if (pci_is_root_bus(pdev->bus))
  36                         break;
  37                 pdev = pdev->bus->self;
  38                 /* a p2p bridge */
  39                 if (!pci_is_pcie(pdev)) {
  40                         tmp = pdev;
  41                         continue;
  42                 }
  43                 /* PCI device should connect to a PCIe bridge */
  44                 if (pci_pcie_type(pdev) != PCI_EXP_TYPE_PCI_BRIDGE) {
  45                         /* Busted hardware? */
  46                         WARN_ON_ONCE(1);
  47                         return NULL;
  48                 }
  49                 return pdev;
  50         }
  51
  52         return tmp;
  53 }
  54
  55 static struct pci_bus *pci_do_find_bus(struct pci_bus *bus, unsigned char busnr)
  56 {
  57         struct pci_bus* child;
  58         struct list_head *tmp;
  59
  60         if(bus->number == busnr)
  61                 return bus;
  62
  63         list_for_each(tmp, &bus->children) {
  64                 child = pci_do_find_bus(pci_bus_b(tmp), busnr);
  65                 if(child)
  66                         return child;
  67         }
  68         return NULL;
  69 }
  70
  71 /**
  72  * pci_find_bus - locate PCI bus from a given domain and bus number
  73  * @domain: number of PCI domain to search
  74  * @busnr: number of desired PCI bus
  75  *
  76  * Given a PCI bus number and domain number, the desired PCI bus is located
  77  * in the global list of PCI buses.  If the bus is found, a pointer to its
  78  * data structure is returned.  If no bus is found, %NULL is returned.
  79  */
  80 struct pci_bus * pci_find_bus(int domain, int busnr)
  81 {
  82         struct pci_bus *bus = NULL;
  83         struct pci_bus *tmp_bus;
  84
  85         while ((bus = pci_find_next_bus(bus)) != NULL)  {
  86                 if (pci_domain_nr(bus) != domain)
  87                         continue;
  88                 tmp_bus = pci_do_find_bus(bus, busnr);
  89                 if (tmp_bus)
  90                         return tmp_bus;
  91         }
  92         return NULL;
  93 }
  94
  95 /**
  96  * pci_find_next_bus - begin or continue searching for a PCI bus
  97  * @from: Previous PCI bus found, or %NULL for new search.
  98  *
  99  * Iterates through the list of known PCI busses.  A new search is
 100  * initiated by passing %NULL as the @from argument.  Otherwise if
 101  * @from is not %NULL, searches continue from next device on the
 102  * global list.
 103  */
 104 struct pci_bus *
 105 pci_find_next_bus(const struct pci_bus *from)
 106 {
 107         struct list_head *n;
 108         struct pci_bus *b = NULL;
 109
 110         WARN_ON(in_interrupt());
 111         down_read(&pci_bus_sem);
 112         n = from ? from->node.next : pci_root_buses.next;
 113         if (n != &pci_root_buses)
 114                 b = pci_bus_b(n);
 115         up_read(&pci_bus_sem);
 116         return b;
 117 }
 118
 119 /**
 120  * pci_get_slot - locate PCI device for a given PCI slot
 121  * @bus: PCI bus on which desired PCI device resides
 122  * @devfn: encodes number of PCI slot in which the desired PCI
 123  * device resides and the logical device number within that slot
 124  * in case of multi-function devices.
 125  *
 126  * Given a PCI bus and slot/function number, the desired PCI device
 127  * is located in the list of PCI devices.
 128  * If the device is found, its reference count is increased and this
 129  * function returns a pointer to its data structure.  The caller must
 130  * decrement the reference count by calling pci_dev_put().
 131  * If no device is found, %NULL is returned.
 132  */
 133 struct pci_dev *pci_get_slot(struct pci_bus *bus, unsigned int devfn)
 134 {
 135         struct pci_dev *dev;
 136
 137         WARN_ON(in_interrupt());
 138         down_read(&pci_bus_sem);
 139
 140         list_for_each_entry(dev, &bus->devices, bus_list) {
 141                 if (dev->devfn == devfn)
 142                         goto out;
 143         }
 144
 145         dev = NULL;
 146  out:
 147         pci_dev_get(dev);
 148         up_read(&pci_bus_sem);
 149         return dev;
 150 }
 151
 152 /**
 153  * pci_get_domain_bus_and_slot - locate PCI device for a given PCI domain (segment), bus, and slot
 154  * @domain: PCI domain/segment on which the PCI device resides.
 155  * @bus: PCI bus on which desired PCI device resides
 156  * @devfn: encodes number of PCI slot in which the desired PCI device
 157  * resides and the logical device number within that slot in case of
 158  * multi-function devices.
 159  *
 160  * Given a PCI domain, bus, and slot/function number, the desired PCI
 161  * device is located in the list of PCI devices. If the device is
 162  * found, its reference count is increased and this function returns a
 163  * pointer to its data structure.  The caller must decrement the
 164  * reference count by calling pci_dev_put().  If no device is found,
 165  * %NULL is returned.
 166  */
 167 struct pci_dev *pci_get_domain_bus_and_slot(int domain, unsigned int bus,
 168                                             unsigned int devfn)
 169 {
 170         struct pci_dev *dev = NULL;
 171
 172         for_each_pci_dev(dev) {
 173                 if (pci_domain_nr(dev->bus) == domain &&
 174                     (dev->bus->number == bus && dev->devfn == devfn))
 175                         return dev;
 176         }
 177         return NULL;
 178 }
 179 EXPORT_SYMBOL(pci_get_domain_bus_and_slot);
 180
 181 static int match_pci_dev_by_id(struct device *dev, void *data)
 182 {
 183         struct pci_dev *pdev = to_pci_dev(dev);
 184         struct pci_device_id *id = data;
 185
 186         if (pci_match_one_device(id, pdev))
 187                 return 1;
 188         return 0;
 189 }
 190
 191 /*
 192  * pci_get_dev_by_id - begin or continue searching for a PCI device by id
 193  * @id: pointer to struct pci_device_id to match for the device
 194  * @from: Previous PCI device found in search, or %NULL for new search.
 195  *
 196  * Iterates through the list of known PCI devices.  If a PCI device is found
 197  * with a matching id a pointer to its device structure is returned, and the
 198  * reference count to the device is incremented.  Otherwise, %NULL is returned.
 199  * A new search is initiated by passing %NULL as the @from argument.  Otherwise
 200  * if @from is not %NULL, searches continue from next device on the global
 201  * list.  The reference count for @from is always decremented if it is not
 202  * %NULL.
 203  *
 204  * This is an internal function for use by the other search functions in
 205  * this file.
 206  */
 207 static struct pci_dev *pci_get_dev_by_id(const struct pci_device_id *id,
 208                                          struct pci_dev *from)
 209 {
 210         struct device *dev;
 211         struct device *dev_start = NULL;
 212         struct pci_dev *pdev = NULL;
 213
 214         WARN_ON(in_interrupt());
 215         if (from)
 216                 dev_start = &from->dev;
 217         dev = bus_find_device(&pci_bus_type, dev_start, (void *)id,
 218                               match_pci_dev_by_id);
 219         if (dev)
 220                 pdev = to_pci_dev(dev);
 221         if (from)
 222                 pci_dev_put(from);
 223         return pdev;
 224 }
 225
 226 /**
 227  * pci_get_subsys - begin or continue searching for a PCI device by vendor/subvendor/device/subdevice id
 228  * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
 229  * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
 230  * @ss_vendor: PCI subsystem vendor id to match, or %PCI_ANY_ID to match all vendor ids
 231  * @ss_device: PCI subsystem device id to match, or %PCI_ANY_ID to match all device ids
 232  * @from: Previous PCI device found in search, or %NULL for new search.
 233  *
 234  * Iterates through the list of known PCI devices.  If a PCI device is found
 235  * with a matching @vendor, @device, @ss_vendor and @ss_device, a pointer to its
 236  * device structure is returned, and the reference count to the device is
 237  * incremented.  Otherwise, %NULL is returned.  A new search is initiated by
 238  * passing %NULL as the @from argument.  Otherwise if @from is not %NULL,
 239  * searches continue from next device on the global list.
 240  * The reference count for @from is always decremented if it is not %NULL.
 241  */
 242 struct pci_dev *pci_get_subsys(unsigned int vendor, unsigned int device,
 243                                unsigned int ss_vendor, unsigned int ss_device,
 244                                struct pci_dev *from)
 245 {
 246         struct pci_device_id id = {
 247                 .vendor = vendor,
 248                 .device = device,
 249                 .subvendor = ss_vendor,
 250                 .subdevice = ss_device,
 251         };
 252
 253         return pci_get_dev_by_id(&id, from);
 254 }
 255
 256 /**
 257  * pci_get_device - begin or continue searching for a PCI device by vendor/device id
 258  * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
 259  * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
 260  * @from: Previous PCI device found in search, or %NULL for new search.
 261  *
 262  * Iterates through the list of known PCI devices.  If a PCI device is
 263  * found with a matching @vendor and @device, the reference count to the
 264  * device is incremented and a pointer to its device structure is returned.
 265  * Otherwise, %NULL is returned.  A new search is initiated by passing %NULL
 266  * as the @from argument.  Otherwise if @from is not %NULL, searches continue
 267  * from next device on the global list.  The reference count for @from is
 268  * always decremented if it is not %NULL.
 269  */
 270 struct pci_dev *
 271 pci_get_device(unsigned int vendor, unsigned int device, struct pci_dev *from)
 272 {
 273         return pci_get_subsys(vendor, device, PCI_ANY_ID, PCI_ANY_ID, from);
 274 }
 275
 276 /**
 277  * pci_get_class - begin or continue searching for a PCI device by class
 278  * @class: search for a PCI device with this class designation
 279  * @from: Previous PCI device found in search, or %NULL for new search.
 280  *
 281  * Iterates through the list of known PCI devices.  If a PCI device is
 282  * found with a matching @class, the reference count to the device is
 283  * incremented and a pointer to its device structure is returned.
 284  * Otherwise, %NULL is returned.
 285  * A new search is initiated by passing %NULL as the @from argument.
 286  * Otherwise if @from is not %NULL, searches continue from next device
 287  * on the global list.  The reference count for @from is always decremented
 288  * if it is not %NULL.
 289  */
 290 struct pci_dev *pci_get_class(unsigned int class, struct pci_dev *from)
 291 {
 292         struct pci_device_id id = {
 293                 .vendor = PCI_ANY_ID,
 294                 .device = PCI_ANY_ID,
 295                 .subvendor = PCI_ANY_ID,
 296                 .subdevice = PCI_ANY_ID,
 297                 .class_mask = PCI_ANY_ID,
 298                 .class = class,
 299         };
 300
 301         return pci_get_dev_by_id(&id, from);
 302 }
 303
 304 /**
 305  * pci_dev_present - Returns 1 if device matching the device list is present, 0 if not.
 306  * @ids: A pointer to a null terminated list of struct pci_device_id structures
 307  * that describe the type of PCI device the caller is trying to find.
 308  *
 309  * Obvious fact: You do not have a reference to any device that might be found
 310  * by this function, so if that device is removed from the system right after
 311  * this function is finished, the value will be stale.  Use this function to
 312  * find devices that are usually built into a system, or for a general hint as
 313  * to if another device happens to be present at this specific moment in time.
 314  */
 315 int pci_dev_present(const struct pci_device_id *ids)
 316 {
 317         struct pci_dev *found = NULL;
 318
 319         WARN_ON(in_interrupt());
 320         while (ids->vendor || ids->subvendor || ids->class_mask) {
 321                 found = pci_get_dev_by_id(ids, NULL);
 322                 if (found) {
 323                         pci_dev_put(found);
 324                         return 1;
 325                 }
 326                 ids++;
 327         }
 328
 329         return 0;
 330 }
 331 EXPORT_SYMBOL(pci_dev_present);
 332
 333 /* For boot time work */
 334 EXPORT_SYMBOL(pci_find_bus);
 335 EXPORT_SYMBOL(pci_find_next_bus);
 336 /* For everyone */
 337 EXPORT_SYMBOL(pci_get_device);
 338 EXPORT_SYMBOL(pci_get_subsys);
 339 EXPORT_SYMBOL(pci_get_slot);
 340 EXPORT_SYMBOL(pci_get_class);