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 /* 36 * The device may have an explicit alias requester ID for DMA where the 37 * requester is on another PCI bus. 38 */ 39 pdev = pci_real_dma_dev(pdev); 40 41 ret = fn(pdev, pci_dev_id(pdev), data); 42 if (ret) 43 return ret; 44 45 /* 46 * If the device is broken and uses an alias requester ID for 47 * DMA, iterate over that too. 48 */ 49 if (unlikely(pdev->dma_alias_mask)) { 50 unsigned int devfn; 51 52 for_each_set_bit(devfn, pdev->dma_alias_mask, MAX_NR_DEVFNS) { 53 ret = fn(pdev, PCI_DEVID(pdev->bus->number, devfn), 54 data); 55 if (ret) 56 return ret; 57 } 58 } 59 60 for (bus = pdev->bus; !pci_is_root_bus(bus); bus = bus->parent) { 61 struct pci_dev *tmp; 62 63 /* Skip virtual buses */ 64 if (!bus->self) 65 continue; 66 67 tmp = bus->self; 68 69 /* stop at bridge where translation unit is associated */ 70 if (tmp->dev_flags & PCI_DEV_FLAGS_BRIDGE_XLATE_ROOT) 71 return ret; 72 73 /* 74 * PCIe-to-PCI/X bridges alias transactions from downstream 75 * devices using the subordinate bus number (PCI Express to 76 * PCI/PCI-X Bridge Spec, rev 1.0, sec 2.3). For all cases 77 * where the upstream bus is PCI/X we alias to the bridge 78 * (there are various conditions in the previous reference 79 * where the bridge may take ownership of transactions, even 80 * when the secondary interface is PCI-X). 81 */ 82 if (pci_is_pcie(tmp)) { 83 switch (pci_pcie_type(tmp)) { 84 case PCI_EXP_TYPE_ROOT_PORT: 85 case PCI_EXP_TYPE_UPSTREAM: 86 case PCI_EXP_TYPE_DOWNSTREAM: 87 continue; 88 case PCI_EXP_TYPE_PCI_BRIDGE: 89 ret = fn(tmp, 90 PCI_DEVID(tmp->subordinate->number, 91 PCI_DEVFN(0, 0)), data); 92 if (ret) 93 return ret; 94 continue; 95 case PCI_EXP_TYPE_PCIE_BRIDGE: 96 ret = fn(tmp, pci_dev_id(tmp), data); 97 if (ret) 98 return ret; 99 continue; 100 } 101 } else { 102 if (tmp->dev_flags & PCI_DEV_FLAG_PCIE_BRIDGE_ALIAS) 103 ret = fn(tmp, 104 PCI_DEVID(tmp->subordinate->number, 105 PCI_DEVFN(0, 0)), data); 106 else 107 ret = fn(tmp, pci_dev_id(tmp), data); 108 if (ret) 109 return ret; 110 } 111 } 112 113 return ret; 114 } 115 116 static struct pci_bus *pci_do_find_bus(struct pci_bus *bus, unsigned char busnr) 117 { 118 struct pci_bus *child; 119 struct pci_bus *tmp; 120 121 if (bus->number == busnr) 122 return bus; 123 124 list_for_each_entry(tmp, &bus->children, node) { 125 child = pci_do_find_bus(tmp, busnr); 126 if (child) 127 return child; 128 } 129 return NULL; 130 } 131 132 /** 133 * pci_find_bus - locate PCI bus from a given domain and bus number 134 * @domain: number of PCI domain to search 135 * @busnr: number of desired PCI bus 136 * 137 * Given a PCI bus number and domain number, the desired PCI bus is located 138 * in the global list of PCI buses. If the bus is found, a pointer to its 139 * data structure is returned. If no bus is found, %NULL is returned. 140 */ 141 struct pci_bus *pci_find_bus(int domain, int busnr) 142 { 143 struct pci_bus *bus = NULL; 144 struct pci_bus *tmp_bus; 145 146 while ((bus = pci_find_next_bus(bus)) != NULL) { 147 if (pci_domain_nr(bus) != domain) 148 continue; 149 tmp_bus = pci_do_find_bus(bus, busnr); 150 if (tmp_bus) 151 return tmp_bus; 152 } 153 return NULL; 154 } 155 EXPORT_SYMBOL(pci_find_bus); 156 157 /** 158 * pci_find_next_bus - begin or continue searching for a PCI bus 159 * @from: Previous PCI bus found, or %NULL for new search. 160 * 161 * Iterates through the list of known PCI buses. A new search is 162 * initiated by passing %NULL as the @from argument. Otherwise if 163 * @from is not %NULL, searches continue from next device on the 164 * global list. 165 */ 166 struct pci_bus *pci_find_next_bus(const struct pci_bus *from) 167 { 168 struct list_head *n; 169 struct pci_bus *b = NULL; 170 171 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 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, const void *data) 243 { 244 struct pci_dev *pdev = to_pci_dev(dev); 245 const 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 if (from) 276 dev_start = &from->dev; 277 dev = bus_find_device(&pci_bus_type, dev_start, (void *)id, 278 match_pci_dev_by_id); 279 if (dev) 280 pdev = to_pci_dev(dev); 281 pci_dev_put(from); 282 return pdev; 283 } 284 285 /** 286 * pci_get_subsys - begin or continue searching for a PCI device by vendor/subvendor/device/subdevice id 287 * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids 288 * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids 289 * @ss_vendor: PCI subsystem vendor id to match, or %PCI_ANY_ID to match all vendor ids 290 * @ss_device: PCI subsystem device id to match, or %PCI_ANY_ID to match all device ids 291 * @from: Previous PCI device found in search, or %NULL for new search. 292 * 293 * Iterates through the list of known PCI devices. If a PCI device is found 294 * with a matching @vendor, @device, @ss_vendor and @ss_device, a pointer to its 295 * device structure is returned, and the reference count to the device is 296 * incremented. Otherwise, %NULL is returned. A new search is initiated by 297 * passing %NULL as the @from argument. Otherwise if @from is not %NULL, 298 * searches continue from next device on the global list. 299 * The reference count for @from is always decremented if it is not %NULL. 300 */ 301 struct pci_dev *pci_get_subsys(unsigned int vendor, unsigned int device, 302 unsigned int ss_vendor, unsigned int ss_device, 303 struct pci_dev *from) 304 { 305 struct pci_device_id id = { 306 .vendor = vendor, 307 .device = device, 308 .subvendor = ss_vendor, 309 .subdevice = ss_device, 310 }; 311 312 return pci_get_dev_by_id(&id, from); 313 } 314 EXPORT_SYMBOL(pci_get_subsys); 315 316 /** 317 * pci_get_device - begin or continue searching for a PCI device by vendor/device id 318 * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids 319 * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids 320 * @from: Previous PCI device found in search, or %NULL for new search. 321 * 322 * Iterates through the list of known PCI devices. If a PCI device is 323 * found with a matching @vendor and @device, the reference count to the 324 * device is incremented and a pointer to its device structure is returned. 325 * Otherwise, %NULL is returned. A new search is initiated by passing %NULL 326 * as the @from argument. Otherwise if @from is not %NULL, searches continue 327 * from next device on the global list. The reference count for @from is 328 * always decremented if it is not %NULL. 329 */ 330 struct pci_dev *pci_get_device(unsigned int vendor, unsigned int device, 331 struct pci_dev *from) 332 { 333 return pci_get_subsys(vendor, device, PCI_ANY_ID, PCI_ANY_ID, from); 334 } 335 EXPORT_SYMBOL(pci_get_device); 336 337 /** 338 * pci_get_class - begin or continue searching for a PCI device by class 339 * @class: search for a PCI device with this class designation 340 * @from: Previous PCI device found in search, or %NULL for new search. 341 * 342 * Iterates through the list of known PCI devices. If a PCI device is 343 * found with a matching @class, the reference count to the device is 344 * incremented and a pointer to its device structure is returned. 345 * Otherwise, %NULL is returned. 346 * A new search is initiated by passing %NULL as the @from argument. 347 * Otherwise if @from is not %NULL, searches continue from next device 348 * on the global list. The reference count for @from is always decremented 349 * if it is not %NULL. 350 */ 351 struct pci_dev *pci_get_class(unsigned int class, struct pci_dev *from) 352 { 353 struct pci_device_id id = { 354 .vendor = PCI_ANY_ID, 355 .device = PCI_ANY_ID, 356 .subvendor = PCI_ANY_ID, 357 .subdevice = PCI_ANY_ID, 358 .class_mask = PCI_ANY_ID, 359 .class = class, 360 }; 361 362 return pci_get_dev_by_id(&id, from); 363 } 364 EXPORT_SYMBOL(pci_get_class); 365 366 /** 367 * pci_dev_present - Returns 1 if device matching the device list is present, 0 if not. 368 * @ids: A pointer to a null terminated list of struct pci_device_id structures 369 * that describe the type of PCI device the caller is trying to find. 370 * 371 * Obvious fact: You do not have a reference to any device that might be found 372 * by this function, so if that device is removed from the system right after 373 * this function is finished, the value will be stale. Use this function to 374 * find devices that are usually built into a system, or for a general hint as 375 * to if another device happens to be present at this specific moment in time. 376 */ 377 int pci_dev_present(const struct pci_device_id *ids) 378 { 379 struct pci_dev *found = NULL; 380 381 while (ids->vendor || ids->subvendor || ids->class_mask) { 382 found = pci_get_dev_by_id(ids, NULL); 383 if (found) { 384 pci_dev_put(found); 385 return 1; 386 } 387 ids++; 388 } 389 390 return 0; 391 } 392 EXPORT_SYMBOL(pci_dev_present); 393