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