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 /*
  19  * find the upstream PCIe-to-PCI bridge of a PCI device
  20  * if the device is PCIE, return NULL
  21  * if the device isn't connected to a PCIe bridge (that is its parent is a
  22  * legacy PCI bridge and the bridge is directly connected to bus 0), return its
  23  * parent
  24  */
  25 struct pci_dev *
  26 pci_find_upstream_pcie_bridge(struct pci_dev *pdev)
  27 {
  28         struct pci_dev *tmp = NULL;
  29
  30         if (pci_is_pcie(pdev))
  31                 return NULL;
  32         while (1) {
  33                 if (pci_is_root_bus(pdev->bus))
  34                         break;
  35                 pdev = pdev->bus->self;
  36                 /* a p2p bridge */
  37                 if (!pci_is_pcie(pdev)) {
  38                         tmp = pdev;
  39                         continue;
  40                 }
  41                 /* PCI device should connect to a PCIe bridge */
  42                 if (pdev->pcie_type != PCI_EXP_TYPE_PCI_BRIDGE) {
  43                         /* Busted hardware? */
  44                         WARN_ON_ONCE(1);
  45                         return NULL;
  46                 }
  47                 return pdev;
  48         }
  49
  50         return tmp;
  51 }
  52
  53 static struct pci_bus *pci_do_find_bus(struct pci_bus *bus, unsigned char busnr)
  54 {
  55         struct pci_bus* child;
  56         struct list_head *tmp;
  57
  58         if(bus->number == busnr)
  59                 return bus;
  60
  61         list_for_each(tmp, &bus->children) {
  62                 child = pci_do_find_bus(pci_bus_b(tmp), busnr);
  63                 if(child)
  64                         return child;
  65         }
  66         return NULL;
  67 }
  68
  69 /**
  70  * pci_find_bus - locate PCI bus from a given domain and bus number
  71  * @domain: number of PCI domain to search
  72  * @busnr: number of desired PCI bus
  73  *
  74  * Given a PCI bus number and domain number, the desired PCI bus is located
  75  * in the global list of PCI buses.  If the bus is found, a pointer to its
  76  * data structure is returned.  If no bus is found, %NULL is returned.
  77  */
  78 struct pci_bus * pci_find_bus(int domain, int busnr)
  79 {
  80         struct pci_bus *bus = NULL;
  81         struct pci_bus *tmp_bus;
  82
  83         while ((bus = pci_find_next_bus(bus)) != NULL)  {
  84                 if (pci_domain_nr(bus) != domain)
  85                         continue;
  86                 tmp_bus = pci_do_find_bus(bus, busnr);
  87                 if (tmp_bus)
  88                         return tmp_bus;
  89         }
  90         return NULL;
  91 }
  92
  93 /**
  94  * pci_find_next_bus - begin or continue searching for a PCI bus
  95  * @from: Previous PCI bus found, or %NULL for new search.
  96  *
  97  * Iterates through the list of known PCI busses.  A new search is
  98  * initiated by passing %NULL as the @from argument.  Otherwise if
  99  * @from is not %NULL, searches continue from next device on the
 100  * global list.
 101  */
 102 struct pci_bus *
 103 pci_find_next_bus(const struct pci_bus *from)
 104 {
 105         struct list_head *n;
 106         struct pci_bus *b = NULL;
 107
 108         WARN_ON(in_interrupt());
 109         down_read(&pci_bus_sem);
 110         n = from ? from->node.next : pci_root_buses.next;
 111         if (n != &pci_root_buses)
 112                 b = pci_bus_b(n);
 113         up_read(&pci_bus_sem);
 114         return b;
 115 }
 116
 117 /**
 118  * pci_get_slot - locate PCI device for a given PCI slot
 119  * @bus: PCI bus on which desired PCI device resides
 120  * @devfn: encodes number of PCI slot in which the desired PCI
 121  * device resides and the logical device number within that slot
 122  * in case of multi-function devices.
 123  *
 124  * Given a PCI bus and slot/function number, the desired PCI device
 125  * is located in the list of PCI devices.
 126  * If the device is found, its reference count is increased and this
 127  * function returns a pointer to its data structure.  The caller must
 128  * decrement the reference count by calling pci_dev_put().
 129  * If no device is found, %NULL is returned.
 130  */
 131 struct pci_dev * pci_get_slot(struct pci_bus *bus, unsigned int devfn)
 132 {
 133         struct list_head *tmp;
 134         struct pci_dev *dev;
 135
 136         WARN_ON(in_interrupt());
 137         down_read(&pci_bus_sem);
 138
 139         list_for_each(tmp, &bus->devices) {
 140                 dev = pci_dev_b(tmp);
 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_dev *pdev;
 247         struct pci_device_id *id;
 248
 249         /*
 250          * pci_find_subsys() can be called on the ide_setup() path,
 251          * super-early in boot.  But the down_read() will enable local
 252          * interrupts, which can cause some machines to crash.  So here we
 253          * detect and flag that situation and bail out early.
 254          */
 255         if (unlikely(no_pci_devices()))
 256                 return NULL;
 257
 258         id = kzalloc(sizeof(*id), GFP_KERNEL);
 259         if (!id)
 260                 return NULL;
 261         id->vendor = vendor;
 262         id->device = device;
 263         id->subvendor = ss_vendor;
 264         id->subdevice = ss_device;
 265
 266         pdev = pci_get_dev_by_id(id, from);
 267         kfree(id);
 268
 269         return pdev;
 270 }
 271
 272 /**
 273  * pci_get_device - begin or continue searching for a PCI device by vendor/device id
 274  * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
 275  * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
 276  * @from: Previous PCI device found in search, or %NULL for new search.
 277  *
 278  * Iterates through the list of known PCI devices.  If a PCI device is
 279  * found with a matching @vendor and @device, the reference count to the
 280  * device is incremented and a pointer to its device structure is returned.
 281  * Otherwise, %NULL is returned.  A new search is initiated by passing %NULL
 282  * as the @from argument.  Otherwise if @from is not %NULL, searches continue
 283  * from next device on the global list.  The reference count for @from is
 284  * always decremented if it is not %NULL.
 285  */
 286 struct pci_dev *
 287 pci_get_device(unsigned int vendor, unsigned int device, struct pci_dev *from)
 288 {
 289         return pci_get_subsys(vendor, device, PCI_ANY_ID, PCI_ANY_ID, from);
 290 }
 291
 292 /**
 293  * pci_get_class - begin or continue searching for a PCI device by class
 294  * @class: search for a PCI device with this class designation
 295  * @from: Previous PCI device found in search, or %NULL for new search.
 296  *
 297  * Iterates through the list of known PCI devices.  If a PCI device is
 298  * found with a matching @class, the reference count to the device is
 299  * incremented and a pointer to its device structure is returned.
 300  * Otherwise, %NULL is returned.
 301  * A new search is initiated by passing %NULL as the @from argument.
 302  * Otherwise if @from is not %NULL, searches continue from next device
 303  * on the global list.  The reference count for @from is always decremented
 304  * if it is not %NULL.
 305  */
 306 struct pci_dev *pci_get_class(unsigned int class, struct pci_dev *from)
 307 {
 308         struct pci_dev *dev;
 309         struct pci_device_id *id;
 310
 311         id = kzalloc(sizeof(*id), GFP_KERNEL);
 312         if (!id)
 313                 return NULL;
 314         id->vendor = id->device = id->subvendor = id->subdevice = PCI_ANY_ID;
 315         id->class_mask = PCI_ANY_ID;
 316         id->class = class;
 317
 318         dev = pci_get_dev_by_id(id, from);
 319         kfree(id);
 320         return dev;
 321 }
 322
 323 /**
 324  * pci_dev_present - Returns 1 if device matching the device list is present, 0 if not.
 325  * @ids: A pointer to a null terminated list of struct pci_device_id structures
 326  * that describe the type of PCI device the caller is trying to find.
 327  *
 328  * Obvious fact: You do not have a reference to any device that might be found
 329  * by this function, so if that device is removed from the system right after
 330  * this function is finished, the value will be stale.  Use this function to
 331  * find devices that are usually built into a system, or for a general hint as
 332  * to if another device happens to be present at this specific moment in time.
 333  */
 334 int pci_dev_present(const struct pci_device_id *ids)
 335 {
 336         struct pci_dev *found = NULL;
 337
 338         WARN_ON(in_interrupt());
 339         while (ids->vendor || ids->subvendor || ids->class_mask) {
 340                 found = pci_get_dev_by_id(ids, NULL);
 341                 if (found)
 342                         goto exit;
 343                 ids++;
 344         }
 345 exit:
 346         if (found)
 347                 return 1;
 348         return 0;
 349 }
 350 EXPORT_SYMBOL(pci_dev_present);
 351
 352 /* For boot time work */
 353 EXPORT_SYMBOL(pci_find_bus);
 354 EXPORT_SYMBOL(pci_find_next_bus);
 355 /* For everyone */
 356 EXPORT_SYMBOL(pci_get_device);
 357 EXPORT_SYMBOL(pci_get_subsys);
 358 EXPORT_SYMBOL(pci_get_slot);
 359 EXPORT_SYMBOL(pci_get_class);