1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * PCI searching functions 4 * 5 * Copyright (C) 1993 -- 1997 Drew Eckhardt, Frederic Potter, 6 * David Mosberger-Tang 7 * Copyright (C) 1997 -- 2000 Martin Mares <mj@ucw.cz> 8 * Copyright (C) 2003 -- 2004 Greg Kroah-Hartman <greg@kroah.com> 9 */ 10 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 * pci_for_each_dma_alias - Iterate over DMA aliases for a device 22 * @pdev: starting downstream device 23 * @fn: function to call for each alias 24 * @data: opaque data to pass to @fn 25 * 26 * Starting @pdev, walk up the bus calling @fn for each possible alias 27 * of @pdev at the root bus. 28 */ 29 int pci_for_each_dma_alias(struct pci_dev *pdev, 30 int (*fn)(struct pci_dev *pdev, 31 u16 alias, void *data), void *data) 32 { 33 struct pci_bus *bus; 34 int ret; 35 36 ret = fn(pdev, PCI_DEVID(pdev->bus->number, pdev->devfn), data); 37 if (ret) 38 return ret; 39 40 /* 41 * If the device is broken and uses an alias requester ID for 42 * DMA, iterate over that too. 43 */ 44 if (unlikely(pdev->dma_alias_mask)) { 45 u8 devfn; 46 47 for_each_set_bit(devfn, pdev->dma_alias_mask, U8_MAX) { 48 ret = fn(pdev, PCI_DEVID(pdev->bus->number, devfn), 49 data); 50 if (ret) 51 return ret; 52 } 53 } 54 55 for (bus = pdev->bus; !pci_is_root_bus(bus); bus = bus->parent) { 56 struct pci_dev *tmp; 57 58 /* Skip virtual buses */ 59 if (!bus->self) 60 continue; 61 62 tmp = bus->self; 63 64 /* stop at bridge where translation unit is associated */ 65 if (tmp->dev_flags & PCI_DEV_FLAGS_BRIDGE_XLATE_ROOT) 66 return ret; 67 68 /* 69 * PCIe-to-PCI/X bridges alias transactions from downstream 70 * devices using the subordinate bus number (PCI Express to 71 * PCI/PCI-X Bridge Spec, rev 1.0, sec 2.3). For all cases 72 * where the upstream bus is PCI/X we alias to the bridge 73 * (there are various conditions in the previous reference 74 * where the bridge may take ownership of transactions, even 75 * when the secondary interface is PCI-X). 76 */ 77 if (pci_is_pcie(tmp)) { 78 switch (pci_pcie_type(tmp)) { 79 case PCI_EXP_TYPE_ROOT_PORT: 80 case PCI_EXP_TYPE_UPSTREAM: 81 case PCI_EXP_TYPE_DOWNSTREAM: 82 continue; 83 case PCI_EXP_TYPE_PCI_BRIDGE: 84 ret = fn(tmp, 85 PCI_DEVID(tmp->subordinate->number, 86 PCI_DEVFN(0, 0)), data); 87 if (ret) 88 return ret; 89 continue; 90 case PCI_EXP_TYPE_PCIE_BRIDGE: 91 ret = fn(tmp, 92 PCI_DEVID(tmp->bus->number, 93 tmp->devfn), data); 94 if (ret) 95 return ret; 96 continue; 97 } 98 } else { 99 if (tmp->dev_flags & PCI_DEV_FLAG_PCIE_BRIDGE_ALIAS) 100 ret = fn(tmp, 101 PCI_DEVID(tmp->subordinate->number, 102 PCI_DEVFN(0, 0)), data); 103 else 104 ret = fn(tmp, 105 PCI_DEVID(tmp->bus->number, 106 tmp->devfn), data); 107 if (ret) 108 return ret; 109 } 110 } 111 112 return ret; 113 } 114 115 static struct pci_bus *pci_do_find_bus(struct pci_bus *bus, unsigned char busnr) 116 { 117 struct pci_bus *child; 118 struct pci_bus *tmp; 119 120 if (bus->number == busnr) 121 return bus; 122 123 list_for_each_entry(tmp, &bus->children, node) { 124 child = pci_do_find_bus(tmp, busnr); 125 if (child) 126 return child; 127 } 128 return NULL; 129 } 130 131 /** 132 * pci_find_bus - locate PCI bus from a given domain and bus number 133 * @domain: number of PCI domain to search 134 * @busnr: number of desired PCI bus 135 * 136 * Given a PCI bus number and domain number, the desired PCI bus is located 137 * in the global list of PCI buses. If the bus is found, a pointer to its 138 * data structure is returned. If no bus is found, %NULL is returned. 139 */ 140 struct pci_bus *pci_find_bus(int domain, int busnr) 141 { 142 struct pci_bus *bus = NULL; 143 struct pci_bus *tmp_bus; 144 145 while ((bus = pci_find_next_bus(bus)) != NULL) { 146 if (pci_domain_nr(bus) != domain) 147 continue; 148 tmp_bus = pci_do_find_bus(bus, busnr); 149 if (tmp_bus) 150 return tmp_bus; 151 } 152 return NULL; 153 } 154 EXPORT_SYMBOL(pci_find_bus); 155 156 /** 157 * pci_find_next_bus - begin or continue searching for a PCI bus 158 * @from: Previous PCI bus found, or %NULL for new search. 159 * 160 * Iterates through the list of known PCI buses. A new search is 161 * initiated by passing %NULL as the @from argument. Otherwise if 162 * @from is not %NULL, searches continue from next device on the 163 * global list. 164 */ 165 struct pci_bus *pci_find_next_bus(const struct pci_bus *from) 166 { 167 struct list_head *n; 168 struct pci_bus *b = NULL; 169 170 WARN_ON(in_interrupt()); 171 down_read(&pci_bus_sem); 172 n = from ? from->node.next : pci_root_buses.next; 173 if (n != &pci_root_buses) 174 b = list_entry(n, struct pci_bus, node); 175 up_read(&pci_bus_sem); 176 return b; 177 } 178 EXPORT_SYMBOL(pci_find_next_bus); 179 180 /** 181 * pci_get_slot - locate PCI device for a given PCI slot 182 * @bus: PCI bus on which desired PCI device resides 183 * @devfn: encodes number of PCI slot in which the desired PCI 184 * device resides and the logical device number within that slot 185 * in case of multi-function devices. 186 * 187 * Given a PCI bus and slot/function number, the desired PCI device 188 * is located in the list of PCI devices. 189 * If the device is found, its reference count is increased and this 190 * function returns a pointer to its data structure. The caller must 191 * decrement the reference count by calling pci_dev_put(). 192 * If no device is found, %NULL is returned. 193 */ 194 struct pci_dev *pci_get_slot(struct pci_bus *bus, unsigned int devfn) 195 { 196 struct pci_dev *dev; 197 198 WARN_ON(in_interrupt()); 199 down_read(&pci_bus_sem); 200 201 list_for_each_entry(dev, &bus->devices, bus_list) { 202 if (dev->devfn == devfn) 203 goto out; 204 } 205 206 dev = NULL; 207 out: 208 pci_dev_get(dev); 209 up_read(&pci_bus_sem); 210 return dev; 211 } 212 EXPORT_SYMBOL(pci_get_slot); 213 214 /** 215 * pci_get_domain_bus_and_slot - locate PCI device for a given PCI domain (segment), bus, and slot 216 * @domain: PCI domain/segment on which the PCI device resides. 217 * @bus: PCI bus on which desired PCI device resides 218 * @devfn: encodes number of PCI slot in which the desired PCI device 219 * resides and the logical device number within that slot in case of 220 * multi-function devices. 221 * 222 * Given a PCI domain, bus, and slot/function number, the desired PCI 223 * device is located in the list of PCI devices. If the device is 224 * found, its reference count is increased and this function returns a 225 * pointer to its data structure. The caller must decrement the 226 * reference count by calling pci_dev_put(). If no device is found, 227 * %NULL is returned. 228 */ 229 struct pci_dev *pci_get_domain_bus_and_slot(int domain, unsigned int bus, 230 unsigned int devfn) 231 { 232 struct pci_dev *dev = NULL; 233 234 for_each_pci_dev(dev) { 235 if (pci_domain_nr(dev->bus) == domain && 236 (dev->bus->number == bus && dev->devfn == devfn)) 237 return dev; 238 } 239 return NULL; 240 } 241 EXPORT_SYMBOL(pci_get_domain_bus_and_slot); 242 243 static int match_pci_dev_by_id(struct device *dev, void *data) 244 { 245 struct pci_dev *pdev = to_pci_dev(dev); 246 struct pci_device_id *id = data; 247 248 if (pci_match_one_device(id, pdev)) 249 return 1; 250 return 0; 251 } 252 253 /* 254 * pci_get_dev_by_id - begin or continue searching for a PCI device by id 255 * @id: pointer to struct pci_device_id to match for the device 256 * @from: Previous PCI device found in search, or %NULL for new search. 257 * 258 * Iterates through the list of known PCI devices. If a PCI device is found 259 * with a matching id a pointer to its device structure is returned, and the 260 * reference count to the device is incremented. Otherwise, %NULL is returned. 261 * A new search is initiated by passing %NULL as the @from argument. Otherwise 262 * if @from is not %NULL, searches continue from next device on the global 263 * list. The reference count for @from is always decremented if it is not 264 * %NULL. 265 * 266 * This is an internal function for use by the other search functions in 267 * this file. 268 */ 269 static struct pci_dev *pci_get_dev_by_id(const struct pci_device_id *id, 270 struct pci_dev *from) 271 { 272 struct device *dev; 273 struct device *dev_start = NULL; 274 struct pci_dev *pdev = NULL; 275 276 WARN_ON(in_interrupt()); 277 if (from) 278 dev_start = &from->dev; 279 dev = bus_find_device(&pci_bus_type, dev_start, (void *)id, 280 match_pci_dev_by_id); 281 if (dev) 282 pdev = to_pci_dev(dev); 283 pci_dev_put(from); 284 return pdev; 285 } 286 287 /** 288 * pci_get_subsys - begin or continue searching for a PCI device by vendor/subvendor/device/subdevice id 289 * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids 290 * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids 291 * @ss_vendor: PCI subsystem vendor id to match, or %PCI_ANY_ID to match all vendor ids 292 * @ss_device: PCI subsystem device id to match, or %PCI_ANY_ID to match all device ids 293 * @from: Previous PCI device found in search, or %NULL for new search. 294 * 295 * Iterates through the list of known PCI devices. If a PCI device is found 296 * with a matching @vendor, @device, @ss_vendor and @ss_device, a pointer to its 297 * device structure is returned, and the reference count to the device is 298 * incremented. Otherwise, %NULL is returned. A new search is initiated by 299 * passing %NULL as the @from argument. Otherwise if @from is not %NULL, 300 * searches continue from next device on the global list. 301 * The reference count for @from is always decremented if it is not %NULL. 302 */ 303 struct pci_dev *pci_get_subsys(unsigned int vendor, unsigned int device, 304 unsigned int ss_vendor, unsigned int ss_device, 305 struct pci_dev *from) 306 { 307 struct pci_device_id id = { 308 .vendor = vendor, 309 .device = device, 310 .subvendor = ss_vendor, 311 .subdevice = ss_device, 312 }; 313 314 return pci_get_dev_by_id(&id, from); 315 } 316 EXPORT_SYMBOL(pci_get_subsys); 317 318 /** 319 * pci_get_device - begin or continue searching for a PCI device by vendor/device id 320 * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids 321 * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids 322 * @from: Previous PCI device found in search, or %NULL for new search. 323 * 324 * Iterates through the list of known PCI devices. If a PCI device is 325 * found with a matching @vendor and @device, the reference count to the 326 * device is incremented and a pointer to its device structure is returned. 327 * Otherwise, %NULL is returned. A new search is initiated by passing %NULL 328 * as the @from argument. Otherwise if @from is not %NULL, searches continue 329 * from next device on the global list. The reference count for @from is 330 * always decremented if it is not %NULL. 331 */ 332 struct pci_dev *pci_get_device(unsigned int vendor, unsigned int device, 333 struct pci_dev *from) 334 { 335 return pci_get_subsys(vendor, device, PCI_ANY_ID, PCI_ANY_ID, from); 336 } 337 EXPORT_SYMBOL(pci_get_device); 338 339 /** 340 * pci_get_class - begin or continue searching for a PCI device by class 341 * @class: search for a PCI device with this class designation 342 * @from: Previous PCI device found in search, or %NULL for new search. 343 * 344 * Iterates through the list of known PCI devices. If a PCI device is 345 * found with a matching @class, the reference count to the device is 346 * incremented and a pointer to its device structure is returned. 347 * Otherwise, %NULL is returned. 348 * A new search is initiated by passing %NULL as the @from argument. 349 * Otherwise if @from is not %NULL, searches continue from next device 350 * on the global list. The reference count for @from is always decremented 351 * if it is not %NULL. 352 */ 353 struct pci_dev *pci_get_class(unsigned int class, struct pci_dev *from) 354 { 355 struct pci_device_id id = { 356 .vendor = PCI_ANY_ID, 357 .device = PCI_ANY_ID, 358 .subvendor = PCI_ANY_ID, 359 .subdevice = PCI_ANY_ID, 360 .class_mask = PCI_ANY_ID, 361 .class = class, 362 }; 363 364 return pci_get_dev_by_id(&id, from); 365 } 366 EXPORT_SYMBOL(pci_get_class); 367 368 /** 369 * pci_dev_present - Returns 1 if device matching the device list is present, 0 if not. 370 * @ids: A pointer to a null terminated list of struct pci_device_id structures 371 * that describe the type of PCI device the caller is trying to find. 372 * 373 * Obvious fact: You do not have a reference to any device that might be found 374 * by this function, so if that device is removed from the system right after 375 * this function is finished, the value will be stale. Use this function to 376 * find devices that are usually built into a system, or for a general hint as 377 * to if another device happens to be present at this specific moment in time. 378 */ 379 int pci_dev_present(const struct pci_device_id *ids) 380 { 381 struct pci_dev *found = NULL; 382 383 WARN_ON(in_interrupt()); 384 while (ids->vendor || ids->subvendor || ids->class_mask) { 385 found = pci_get_dev_by_id(ids, NULL); 386 if (found) { 387 pci_dev_put(found); 388 return 1; 389 } 390 ids++; 391 } 392 393 return 0; 394 } 395 EXPORT_SYMBOL(pci_dev_present); 396