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/pci.h> 11 #include <linux/slab.h> 12 #include <linux/module.h> 13 #include <linux/interrupt.h> 14 #include "pci.h" 15 16 DECLARE_RWSEM(pci_bus_sem); 17 EXPORT_SYMBOL_GPL(pci_bus_sem); 18 19 /* 20 * pci_for_each_dma_alias - Iterate over DMA aliases for a device 21 * @pdev: starting downstream device 22 * @fn: function to call for each alias 23 * @data: opaque data to pass to @fn 24 * 25 * Starting @pdev, walk up the bus calling @fn for each possible alias 26 * of @pdev at the root bus. 27 */ 28 int pci_for_each_dma_alias(struct pci_dev *pdev, 29 int (*fn)(struct pci_dev *pdev, 30 u16 alias, void *data), void *data) 31 { 32 struct pci_bus *bus; 33 int ret; 34 35 ret = fn(pdev, PCI_DEVID(pdev->bus->number, pdev->devfn), data); 36 if (ret) 37 return ret; 38 39 /* 40 * If the device is broken and uses an alias requester ID for 41 * DMA, iterate over that too. 42 */ 43 if (unlikely(pdev->dma_alias_mask)) { 44 u8 devfn; 45 46 for_each_set_bit(devfn, pdev->dma_alias_mask, U8_MAX) { 47 ret = fn(pdev, PCI_DEVID(pdev->bus->number, devfn), 48 data); 49 if (ret) 50 return ret; 51 } 52 } 53 54 for (bus = pdev->bus; !pci_is_root_bus(bus); bus = bus->parent) { 55 struct pci_dev *tmp; 56 57 /* Skip virtual buses */ 58 if (!bus->self) 59 continue; 60 61 tmp = bus->self; 62 63 /* stop at bridge where translation unit is associated */ 64 if (tmp->dev_flags & PCI_DEV_FLAGS_BRIDGE_XLATE_ROOT) 65 return ret; 66 67 /* 68 * PCIe-to-PCI/X bridges alias transactions from downstream 69 * devices using the subordinate bus number (PCI Express to 70 * PCI/PCI-X Bridge Spec, rev 1.0, sec 2.3). For all cases 71 * where the upstream bus is PCI/X we alias to the bridge 72 * (there are various conditions in the previous reference 73 * where the bridge may take ownership of transactions, even 74 * when the secondary interface is PCI-X). 75 */ 76 if (pci_is_pcie(tmp)) { 77 switch (pci_pcie_type(tmp)) { 78 case PCI_EXP_TYPE_ROOT_PORT: 79 case PCI_EXP_TYPE_UPSTREAM: 80 case PCI_EXP_TYPE_DOWNSTREAM: 81 continue; 82 case PCI_EXP_TYPE_PCI_BRIDGE: 83 ret = fn(tmp, 84 PCI_DEVID(tmp->subordinate->number, 85 PCI_DEVFN(0, 0)), data); 86 if (ret) 87 return ret; 88 continue; 89 case PCI_EXP_TYPE_PCIE_BRIDGE: 90 ret = fn(tmp, 91 PCI_DEVID(tmp->bus->number, 92 tmp->devfn), data); 93 if (ret) 94 return ret; 95 continue; 96 } 97 } else { 98 if (tmp->dev_flags & PCI_DEV_FLAG_PCIE_BRIDGE_ALIAS) 99 ret = fn(tmp, 100 PCI_DEVID(tmp->subordinate->number, 101 PCI_DEVFN(0, 0)), data); 102 else 103 ret = fn(tmp, 104 PCI_DEVID(tmp->bus->number, 105 tmp->devfn), data); 106 if (ret) 107 return ret; 108 } 109 } 110 111 return ret; 112 } 113 114 static struct pci_bus *pci_do_find_bus(struct pci_bus *bus, unsigned char busnr) 115 { 116 struct pci_bus *child; 117 struct pci_bus *tmp; 118 119 if (bus->number == busnr) 120 return bus; 121 122 list_for_each_entry(tmp, &bus->children, node) { 123 child = pci_do_find_bus(tmp, busnr); 124 if (child) 125 return child; 126 } 127 return NULL; 128 } 129 130 /** 131 * pci_find_bus - locate PCI bus from a given domain and bus number 132 * @domain: number of PCI domain to search 133 * @busnr: number of desired PCI bus 134 * 135 * Given a PCI bus number and domain number, the desired PCI bus is located 136 * in the global list of PCI buses. If the bus is found, a pointer to its 137 * data structure is returned. If no bus is found, %NULL is returned. 138 */ 139 struct pci_bus *pci_find_bus(int domain, int busnr) 140 { 141 struct pci_bus *bus = NULL; 142 struct pci_bus *tmp_bus; 143 144 while ((bus = pci_find_next_bus(bus)) != NULL) { 145 if (pci_domain_nr(bus) != domain) 146 continue; 147 tmp_bus = pci_do_find_bus(bus, busnr); 148 if (tmp_bus) 149 return tmp_bus; 150 } 151 return NULL; 152 } 153 EXPORT_SYMBOL(pci_find_bus); 154 155 /** 156 * pci_find_next_bus - begin or continue searching for a PCI bus 157 * @from: Previous PCI bus found, or %NULL for new search. 158 * 159 * Iterates through the list of known PCI buses. A new search is 160 * initiated by passing %NULL as the @from argument. Otherwise if 161 * @from is not %NULL, searches continue from next device on the 162 * global list. 163 */ 164 struct pci_bus *pci_find_next_bus(const struct pci_bus *from) 165 { 166 struct list_head *n; 167 struct pci_bus *b = NULL; 168 169 WARN_ON(in_interrupt()); 170 down_read(&pci_bus_sem); 171 n = from ? from->node.next : pci_root_buses.next; 172 if (n != &pci_root_buses) 173 b = list_entry(n, struct pci_bus, node); 174 up_read(&pci_bus_sem); 175 return b; 176 } 177 EXPORT_SYMBOL(pci_find_next_bus); 178 179 /** 180 * pci_get_slot - locate PCI device for a given PCI slot 181 * @bus: PCI bus on which desired PCI device resides 182 * @devfn: encodes number of PCI slot in which the desired PCI 183 * device resides and the logical device number within that slot 184 * in case of multi-function devices. 185 * 186 * Given a PCI bus and slot/function number, the desired PCI device 187 * is located in the list of PCI devices. 188 * If the device is found, its reference count is increased and this 189 * function returns a pointer to its data structure. The caller must 190 * decrement the reference count by calling pci_dev_put(). 191 * If no device is found, %NULL is returned. 192 */ 193 struct pci_dev *pci_get_slot(struct pci_bus *bus, unsigned int devfn) 194 { 195 struct pci_dev *dev; 196 197 WARN_ON(in_interrupt()); 198 down_read(&pci_bus_sem); 199 200 list_for_each_entry(dev, &bus->devices, bus_list) { 201 if (dev->devfn == devfn) 202 goto out; 203 } 204 205 dev = NULL; 206 out: 207 pci_dev_get(dev); 208 up_read(&pci_bus_sem); 209 return dev; 210 } 211 EXPORT_SYMBOL(pci_get_slot); 212 213 /** 214 * pci_get_domain_bus_and_slot - locate PCI device for a given PCI domain (segment), bus, and slot 215 * @domain: PCI domain/segment on which the PCI device resides. 216 * @bus: PCI bus on which desired PCI device resides 217 * @devfn: encodes number of PCI slot in which the desired PCI device 218 * resides and the logical device number within that slot in case of 219 * multi-function devices. 220 * 221 * Given a PCI domain, bus, and slot/function number, the desired PCI 222 * device is located in the list of PCI devices. If the device is 223 * found, its reference count is increased and this function returns a 224 * pointer to its data structure. The caller must decrement the 225 * reference count by calling pci_dev_put(). If no device is found, 226 * %NULL is returned. 227 */ 228 struct pci_dev *pci_get_domain_bus_and_slot(int domain, unsigned int bus, 229 unsigned int devfn) 230 { 231 struct pci_dev *dev = NULL; 232 233 for_each_pci_dev(dev) { 234 if (pci_domain_nr(dev->bus) == domain && 235 (dev->bus->number == bus && dev->devfn == devfn)) 236 return dev; 237 } 238 return NULL; 239 } 240 EXPORT_SYMBOL(pci_get_domain_bus_and_slot); 241 242 static int match_pci_dev_by_id(struct device *dev, void *data) 243 { 244 struct pci_dev *pdev = to_pci_dev(dev); 245 struct pci_device_id *id = data; 246 247 if (pci_match_one_device(id, pdev)) 248 return 1; 249 return 0; 250 } 251 252 /* 253 * pci_get_dev_by_id - begin or continue searching for a PCI device by id 254 * @id: pointer to struct pci_device_id to match for the device 255 * @from: Previous PCI device found in search, or %NULL for new search. 256 * 257 * Iterates through the list of known PCI devices. If a PCI device is found 258 * with a matching id a pointer to its device structure is returned, and the 259 * reference count to the device is incremented. Otherwise, %NULL is returned. 260 * A new search is initiated by passing %NULL as the @from argument. Otherwise 261 * if @from is not %NULL, searches continue from next device on the global 262 * list. The reference count for @from is always decremented if it is not 263 * %NULL. 264 * 265 * This is an internal function for use by the other search functions in 266 * this file. 267 */ 268 static struct pci_dev *pci_get_dev_by_id(const struct pci_device_id *id, 269 struct pci_dev *from) 270 { 271 struct device *dev; 272 struct device *dev_start = NULL; 273 struct pci_dev *pdev = NULL; 274 275 WARN_ON(in_interrupt()); 276 if (from) 277 dev_start = &from->dev; 278 dev = bus_find_device(&pci_bus_type, dev_start, (void *)id, 279 match_pci_dev_by_id); 280 if (dev) 281 pdev = to_pci_dev(dev); 282 pci_dev_put(from); 283 return pdev; 284 } 285 286 /** 287 * pci_get_subsys - begin or continue searching for a PCI device by vendor/subvendor/device/subdevice id 288 * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids 289 * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids 290 * @ss_vendor: PCI subsystem vendor id to match, or %PCI_ANY_ID to match all vendor ids 291 * @ss_device: PCI subsystem device id to match, or %PCI_ANY_ID to match all device ids 292 * @from: Previous PCI device found in search, or %NULL for new search. 293 * 294 * Iterates through the list of known PCI devices. If a PCI device is found 295 * with a matching @vendor, @device, @ss_vendor and @ss_device, a pointer to its 296 * device structure is returned, and the reference count to the device is 297 * incremented. Otherwise, %NULL is returned. A new search is initiated by 298 * passing %NULL as the @from argument. Otherwise if @from is not %NULL, 299 * searches continue from next device on the global list. 300 * The reference count for @from is always decremented if it is not %NULL. 301 */ 302 struct pci_dev *pci_get_subsys(unsigned int vendor, unsigned int device, 303 unsigned int ss_vendor, unsigned int ss_device, 304 struct pci_dev *from) 305 { 306 struct pci_device_id id = { 307 .vendor = vendor, 308 .device = device, 309 .subvendor = ss_vendor, 310 .subdevice = ss_device, 311 }; 312 313 return pci_get_dev_by_id(&id, from); 314 } 315 EXPORT_SYMBOL(pci_get_subsys); 316 317 /** 318 * pci_get_device - begin or continue searching for a PCI device by vendor/device id 319 * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids 320 * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids 321 * @from: Previous PCI device found in search, or %NULL for new search. 322 * 323 * Iterates through the list of known PCI devices. If a PCI device is 324 * found with a matching @vendor and @device, the reference count to the 325 * device is incremented and a pointer to its device structure is returned. 326 * Otherwise, %NULL is returned. A new search is initiated by passing %NULL 327 * as the @from argument. Otherwise if @from is not %NULL, searches continue 328 * from next device on the global list. The reference count for @from is 329 * always decremented if it is not %NULL. 330 */ 331 struct pci_dev *pci_get_device(unsigned int vendor, unsigned int device, 332 struct pci_dev *from) 333 { 334 return pci_get_subsys(vendor, device, PCI_ANY_ID, PCI_ANY_ID, from); 335 } 336 EXPORT_SYMBOL(pci_get_device); 337 338 /** 339 * pci_get_class - begin or continue searching for a PCI device by class 340 * @class: search for a PCI device with this class designation 341 * @from: Previous PCI device found in search, or %NULL for new search. 342 * 343 * Iterates through the list of known PCI devices. If a PCI device is 344 * found with a matching @class, the reference count to the device is 345 * incremented and a pointer to its device structure is returned. 346 * Otherwise, %NULL is returned. 347 * A new search is initiated by passing %NULL as the @from argument. 348 * Otherwise if @from is not %NULL, searches continue from next device 349 * on the global list. The reference count for @from is always decremented 350 * if it is not %NULL. 351 */ 352 struct pci_dev *pci_get_class(unsigned int class, struct pci_dev *from) 353 { 354 struct pci_device_id id = { 355 .vendor = PCI_ANY_ID, 356 .device = PCI_ANY_ID, 357 .subvendor = PCI_ANY_ID, 358 .subdevice = PCI_ANY_ID, 359 .class_mask = PCI_ANY_ID, 360 .class = class, 361 }; 362 363 return pci_get_dev_by_id(&id, from); 364 } 365 EXPORT_SYMBOL(pci_get_class); 366 367 /** 368 * pci_dev_present - Returns 1 if device matching the device list is present, 0 if not. 369 * @ids: A pointer to a null terminated list of struct pci_device_id structures 370 * that describe the type of PCI device the caller is trying to find. 371 * 372 * Obvious fact: You do not have a reference to any device that might be found 373 * by this function, so if that device is removed from the system right after 374 * this function is finished, the value will be stale. Use this function to 375 * find devices that are usually built into a system, or for a general hint as 376 * to if another device happens to be present at this specific moment in time. 377 */ 378 int pci_dev_present(const struct pci_device_id *ids) 379 { 380 struct pci_dev *found = NULL; 381 382 WARN_ON(in_interrupt()); 383 while (ids->vendor || ids->subvendor || ids->class_mask) { 384 found = pci_get_dev_by_id(ids, NULL); 385 if (found) { 386 pci_dev_put(found); 387 return 1; 388 } 389 ids++; 390 } 391 392 return 0; 393 } 394 EXPORT_SYMBOL(pci_dev_present); 395