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 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_dev_id(pdev), 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, pci_dev_id(tmp), data); 91 if (ret) 92 return ret; 93 continue; 94 } 95 } else { 96 if (tmp->dev_flags & PCI_DEV_FLAG_PCIE_BRIDGE_ALIAS) 97 ret = fn(tmp, 98 PCI_DEVID(tmp->subordinate->number, 99 PCI_DEVFN(0, 0)), data); 100 else 101 ret = fn(tmp, pci_dev_id(tmp), data); 102 if (ret) 103 return ret; 104 } 105 } 106 107 return ret; 108 } 109 110 static struct pci_bus *pci_do_find_bus(struct pci_bus *bus, unsigned char busnr) 111 { 112 struct pci_bus *child; 113 struct pci_bus *tmp; 114 115 if (bus->number == busnr) 116 return bus; 117 118 list_for_each_entry(tmp, &bus->children, node) { 119 child = pci_do_find_bus(tmp, busnr); 120 if (child) 121 return child; 122 } 123 return NULL; 124 } 125 126 /** 127 * pci_find_bus - locate PCI bus from a given domain and bus number 128 * @domain: number of PCI domain to search 129 * @busnr: number of desired PCI bus 130 * 131 * Given a PCI bus number and domain number, the desired PCI bus is located 132 * in the global list of PCI buses. If the bus is found, a pointer to its 133 * data structure is returned. If no bus is found, %NULL is returned. 134 */ 135 struct pci_bus *pci_find_bus(int domain, int busnr) 136 { 137 struct pci_bus *bus = NULL; 138 struct pci_bus *tmp_bus; 139 140 while ((bus = pci_find_next_bus(bus)) != NULL) { 141 if (pci_domain_nr(bus) != domain) 142 continue; 143 tmp_bus = pci_do_find_bus(bus, busnr); 144 if (tmp_bus) 145 return tmp_bus; 146 } 147 return NULL; 148 } 149 EXPORT_SYMBOL(pci_find_bus); 150 151 /** 152 * pci_find_next_bus - begin or continue searching for a PCI bus 153 * @from: Previous PCI bus found, or %NULL for new search. 154 * 155 * Iterates through the list of known PCI buses. A new search is 156 * initiated by passing %NULL as the @from argument. Otherwise if 157 * @from is not %NULL, searches continue from next device on the 158 * global list. 159 */ 160 struct pci_bus *pci_find_next_bus(const struct pci_bus *from) 161 { 162 struct list_head *n; 163 struct pci_bus *b = NULL; 164 165 WARN_ON(in_interrupt()); 166 down_read(&pci_bus_sem); 167 n = from ? from->node.next : pci_root_buses.next; 168 if (n != &pci_root_buses) 169 b = list_entry(n, struct pci_bus, node); 170 up_read(&pci_bus_sem); 171 return b; 172 } 173 EXPORT_SYMBOL(pci_find_next_bus); 174 175 /** 176 * pci_get_slot - locate PCI device for a given PCI slot 177 * @bus: PCI bus on which desired PCI device resides 178 * @devfn: encodes number of PCI slot in which the desired PCI 179 * device resides and the logical device number within that slot 180 * in case of multi-function devices. 181 * 182 * Given a PCI bus and slot/function number, the desired PCI device 183 * is located in the list of PCI devices. 184 * If the device is found, its reference count is increased and this 185 * function returns a pointer to its data structure. The caller must 186 * decrement the reference count by calling pci_dev_put(). 187 * If no device is found, %NULL is returned. 188 */ 189 struct pci_dev *pci_get_slot(struct pci_bus *bus, unsigned int devfn) 190 { 191 struct pci_dev *dev; 192 193 WARN_ON(in_interrupt()); 194 down_read(&pci_bus_sem); 195 196 list_for_each_entry(dev, &bus->devices, bus_list) { 197 if (dev->devfn == devfn) 198 goto out; 199 } 200 201 dev = NULL; 202 out: 203 pci_dev_get(dev); 204 up_read(&pci_bus_sem); 205 return dev; 206 } 207 EXPORT_SYMBOL(pci_get_slot); 208 209 /** 210 * pci_get_domain_bus_and_slot - locate PCI device for a given PCI domain (segment), bus, and slot 211 * @domain: PCI domain/segment on which the PCI device resides. 212 * @bus: PCI bus on which desired PCI device resides 213 * @devfn: encodes number of PCI slot in which the desired PCI device 214 * resides and the logical device number within that slot in case of 215 * multi-function devices. 216 * 217 * Given a PCI domain, bus, and slot/function number, the desired PCI 218 * device is located in the list of PCI devices. If the device is 219 * found, its reference count is increased and this function returns a 220 * pointer to its data structure. The caller must decrement the 221 * reference count by calling pci_dev_put(). If no device is found, 222 * %NULL is returned. 223 */ 224 struct pci_dev *pci_get_domain_bus_and_slot(int domain, unsigned int bus, 225 unsigned int devfn) 226 { 227 struct pci_dev *dev = NULL; 228 229 for_each_pci_dev(dev) { 230 if (pci_domain_nr(dev->bus) == domain && 231 (dev->bus->number == bus && dev->devfn == devfn)) 232 return dev; 233 } 234 return NULL; 235 } 236 EXPORT_SYMBOL(pci_get_domain_bus_and_slot); 237 238 static int match_pci_dev_by_id(struct device *dev, const void *data) 239 { 240 struct pci_dev *pdev = to_pci_dev(dev); 241 const struct pci_device_id *id = data; 242 243 if (pci_match_one_device(id, pdev)) 244 return 1; 245 return 0; 246 } 247 248 /* 249 * pci_get_dev_by_id - begin or continue searching for a PCI device by id 250 * @id: pointer to struct pci_device_id to match for the device 251 * @from: Previous PCI device found in search, or %NULL for new search. 252 * 253 * Iterates through the list of known PCI devices. If a PCI device is found 254 * with a matching id a pointer to its device structure is returned, and the 255 * reference count to the device is incremented. Otherwise, %NULL is returned. 256 * A new search is initiated by passing %NULL as the @from argument. Otherwise 257 * if @from is not %NULL, searches continue from next device on the global 258 * list. The reference count for @from is always decremented if it is not 259 * %NULL. 260 * 261 * This is an internal function for use by the other search functions in 262 * this file. 263 */ 264 static struct pci_dev *pci_get_dev_by_id(const struct pci_device_id *id, 265 struct pci_dev *from) 266 { 267 struct device *dev; 268 struct device *dev_start = NULL; 269 struct pci_dev *pdev = NULL; 270 271 WARN_ON(in_interrupt()); 272 if (from) 273 dev_start = &from->dev; 274 dev = bus_find_device(&pci_bus_type, dev_start, (void *)id, 275 match_pci_dev_by_id); 276 if (dev) 277 pdev = to_pci_dev(dev); 278 pci_dev_put(from); 279 return pdev; 280 } 281 282 /** 283 * pci_get_subsys - begin or continue searching for a PCI device by vendor/subvendor/device/subdevice id 284 * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids 285 * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids 286 * @ss_vendor: PCI subsystem vendor id to match, or %PCI_ANY_ID to match all vendor ids 287 * @ss_device: PCI subsystem device id to match, or %PCI_ANY_ID to match all device ids 288 * @from: Previous PCI device found in search, or %NULL for new search. 289 * 290 * Iterates through the list of known PCI devices. If a PCI device is found 291 * with a matching @vendor, @device, @ss_vendor and @ss_device, a pointer to its 292 * device structure is returned, and the reference count to the device is 293 * incremented. Otherwise, %NULL is returned. A new search is initiated by 294 * passing %NULL as the @from argument. Otherwise if @from is not %NULL, 295 * searches continue from next device on the global list. 296 * The reference count for @from is always decremented if it is not %NULL. 297 */ 298 struct pci_dev *pci_get_subsys(unsigned int vendor, unsigned int device, 299 unsigned int ss_vendor, unsigned int ss_device, 300 struct pci_dev *from) 301 { 302 struct pci_device_id id = { 303 .vendor = vendor, 304 .device = device, 305 .subvendor = ss_vendor, 306 .subdevice = ss_device, 307 }; 308 309 return pci_get_dev_by_id(&id, from); 310 } 311 EXPORT_SYMBOL(pci_get_subsys); 312 313 /** 314 * pci_get_device - begin or continue searching for a PCI device by vendor/device id 315 * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids 316 * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids 317 * @from: Previous PCI device found in search, or %NULL for new search. 318 * 319 * Iterates through the list of known PCI devices. If a PCI device is 320 * found with a matching @vendor and @device, the reference count to the 321 * device is incremented and a pointer to its device structure is returned. 322 * Otherwise, %NULL is returned. A new search is initiated by passing %NULL 323 * as the @from argument. Otherwise if @from is not %NULL, searches continue 324 * from next device on the global list. The reference count for @from is 325 * always decremented if it is not %NULL. 326 */ 327 struct pci_dev *pci_get_device(unsigned int vendor, unsigned int device, 328 struct pci_dev *from) 329 { 330 return pci_get_subsys(vendor, device, PCI_ANY_ID, PCI_ANY_ID, from); 331 } 332 EXPORT_SYMBOL(pci_get_device); 333 334 /** 335 * pci_get_class - begin or continue searching for a PCI device by class 336 * @class: search for a PCI device with this class designation 337 * @from: Previous PCI device found in search, or %NULL for new search. 338 * 339 * Iterates through the list of known PCI devices. If a PCI device is 340 * found with a matching @class, the reference count to the device is 341 * incremented and a pointer to its device structure is returned. 342 * Otherwise, %NULL is returned. 343 * A new search is initiated by passing %NULL as the @from argument. 344 * Otherwise if @from is not %NULL, searches continue from next device 345 * on the global list. The reference count for @from is always decremented 346 * if it is not %NULL. 347 */ 348 struct pci_dev *pci_get_class(unsigned int class, struct pci_dev *from) 349 { 350 struct pci_device_id id = { 351 .vendor = PCI_ANY_ID, 352 .device = PCI_ANY_ID, 353 .subvendor = PCI_ANY_ID, 354 .subdevice = PCI_ANY_ID, 355 .class_mask = PCI_ANY_ID, 356 .class = class, 357 }; 358 359 return pci_get_dev_by_id(&id, from); 360 } 361 EXPORT_SYMBOL(pci_get_class); 362 363 /** 364 * pci_dev_present - Returns 1 if device matching the device list is present, 0 if not. 365 * @ids: A pointer to a null terminated list of struct pci_device_id structures 366 * that describe the type of PCI device the caller is trying to find. 367 * 368 * Obvious fact: You do not have a reference to any device that might be found 369 * by this function, so if that device is removed from the system right after 370 * this function is finished, the value will be stale. Use this function to 371 * find devices that are usually built into a system, or for a general hint as 372 * to if another device happens to be present at this specific moment in time. 373 */ 374 int pci_dev_present(const struct pci_device_id *ids) 375 { 376 struct pci_dev *found = NULL; 377 378 WARN_ON(in_interrupt()); 379 while (ids->vendor || ids->subvendor || ids->class_mask) { 380 found = pci_get_dev_by_id(ids, NULL); 381 if (found) { 382 pci_dev_put(found); 383 return 1; 384 } 385 ids++; 386 } 387 388 return 0; 389 } 390 EXPORT_SYMBOL(pci_dev_present); 391