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