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); 390