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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * From setup-res.c, by:
4 * Dave Rusling (david.rusling@reo.mts.dec.com)
5 * David Mosberger (davidm@cs.arizona.edu)
6 * David Miller (davem@redhat.com)
7 * Ivan Kokshaysky (ink@jurassic.park.msu.ru)
8 */
9#include <linux/module.h>
10#include <linux/kernel.h>
11#include <linux/pci.h>
12#include <linux/errno.h>
13#include <linux/ioport.h>
14#include <linux/proc_fs.h>
15#include <linux/slab.h>
16
17#include "pci.h"
18
19void pci_add_resource_offset(struct list_head *resources, struct resource *res,
20 resource_size_t offset)
21{
22 struct resource_entry *entry;
23
24 entry = resource_list_create_entry(res, 0);
25 if (!entry) {
26 pr_err("PCI: can't add host bridge window %pR\n", res);
27 return;
28 }
29
30 entry->offset = offset;
31 resource_list_add_tail(entry, resources);
32}
33EXPORT_SYMBOL(pci_add_resource_offset);
34
35void pci_add_resource(struct list_head *resources, struct resource *res)
36{
37 pci_add_resource_offset(resources, res, 0);
38}
39EXPORT_SYMBOL(pci_add_resource);
40
41void pci_free_resource_list(struct list_head *resources)
42{
43 resource_list_free(resources);
44}
45EXPORT_SYMBOL(pci_free_resource_list);
46
47void pci_bus_add_resource(struct pci_bus *bus, struct resource *res,
48 unsigned int flags)
49{
50 struct pci_bus_resource *bus_res;
51
52 bus_res = kzalloc(sizeof(struct pci_bus_resource), GFP_KERNEL);
53 if (!bus_res) {
54 dev_err(&bus->dev, "can't add %pR resource\n", res);
55 return;
56 }
57
58 bus_res->res = res;
59 bus_res->flags = flags;
60 list_add_tail(&bus_res->list, &bus->resources);
61}
62
63struct resource *pci_bus_resource_n(const struct pci_bus *bus, int n)
64{
65 struct pci_bus_resource *bus_res;
66
67 if (n < PCI_BRIDGE_RESOURCE_NUM)
68 return bus->resource[n];
69
70 n -= PCI_BRIDGE_RESOURCE_NUM;
71 list_for_each_entry(bus_res, &bus->resources, list) {
72 if (n-- == 0)
73 return bus_res->res;
74 }
75 return NULL;
76}
77EXPORT_SYMBOL_GPL(pci_bus_resource_n);
78
79void pci_bus_remove_resources(struct pci_bus *bus)
80{
81 int i;
82 struct pci_bus_resource *bus_res, *tmp;
83
84 for (i = 0; i < PCI_BRIDGE_RESOURCE_NUM; i++)
85 bus->resource[i] = NULL;
86
87 list_for_each_entry_safe(bus_res, tmp, &bus->resources, list) {
88 list_del(&bus_res->list);
89 kfree(bus_res);
90 }
91}
92
93int devm_request_pci_bus_resources(struct device *dev,
94 struct list_head *resources)
95{
96 struct resource_entry *win;
97 struct resource *parent, *res;
98 int err;
99
100 resource_list_for_each_entry(win, resources) {
101 res = win->res;
102 switch (resource_type(res)) {
103 case IORESOURCE_IO:
104 parent = &ioport_resource;
105 break;
106 case IORESOURCE_MEM:
107 parent = &iomem_resource;
108 break;
109 default:
110 continue;
111 }
112
113 err = devm_request_resource(dev, parent, res);
114 if (err)
115 return err;
116 }
117
118 return 0;
119}
120EXPORT_SYMBOL_GPL(devm_request_pci_bus_resources);
121
122static struct pci_bus_region pci_32_bit = {0, 0xffffffffULL};
123#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
124static struct pci_bus_region pci_64_bit = {0,
125 (pci_bus_addr_t) 0xffffffffffffffffULL};
126static struct pci_bus_region pci_high = {(pci_bus_addr_t) 0x100000000ULL,
127 (pci_bus_addr_t) 0xffffffffffffffffULL};
128#endif
129
130/*
131 * @res contains CPU addresses. Clip it so the corresponding bus addresses
132 * on @bus are entirely within @region. This is used to control the bus
133 * addresses of resources we allocate, e.g., we may need a resource that
134 * can be mapped by a 32-bit BAR.
135 */
136static void pci_clip_resource_to_region(struct pci_bus *bus,
137 struct resource *res,
138 struct pci_bus_region *region)
139{
140 struct pci_bus_region r;
141
142 pcibios_resource_to_bus(bus, &r, res);
143 if (r.start < region->start)
144 r.start = region->start;
145 if (r.end > region->end)
146 r.end = region->end;
147
148 if (r.end < r.start)
149 res->end = res->start - 1;
150 else
151 pcibios_bus_to_resource(bus, res, &r);
152}
153
154static int pci_bus_alloc_from_region(struct pci_bus *bus, struct resource *res,
155 resource_size_t size, resource_size_t align,
156 resource_size_t min, unsigned long type_mask,
157 resource_size_t (*alignf)(void *,
158 const struct resource *,
159 resource_size_t,
160 resource_size_t),
161 void *alignf_data,
162 struct pci_bus_region *region)
163{
164 int i, ret;
165 struct resource *r, avail;
166 resource_size_t max;
167
168 type_mask |= IORESOURCE_TYPE_BITS;
169
170 pci_bus_for_each_resource(bus, r, i) {
171 resource_size_t min_used = min;
172
173 if (!r)
174 continue;
175
176 /* type_mask must match */
177 if ((res->flags ^ r->flags) & type_mask)
178 continue;
179
180 /* We cannot allocate a non-prefetching resource
181 from a pre-fetching area */
182 if ((r->flags & IORESOURCE_PREFETCH) &&
183 !(res->flags & IORESOURCE_PREFETCH))
184 continue;
185
186 avail = *r;
187 pci_clip_resource_to_region(bus, &avail, region);
188
189 /*
190 * "min" is typically PCIBIOS_MIN_IO or PCIBIOS_MIN_MEM to
191 * protect badly documented motherboard resources, but if
192 * this is an already-configured bridge window, its start
193 * overrides "min".
194 */
195 if (avail.start)
196 min_used = avail.start;
197
198 max = avail.end;
199
200 /* Ok, try it out.. */
201 ret = allocate_resource(r, res, size, min_used, max,
202 align, alignf, alignf_data);
203 if (ret == 0)
204 return 0;
205 }
206 return -ENOMEM;
207}
208
209/**
210 * pci_bus_alloc_resource - allocate a resource from a parent bus
211 * @bus: PCI bus
212 * @res: resource to allocate
213 * @size: size of resource to allocate
214 * @align: alignment of resource to allocate
215 * @min: minimum /proc/iomem address to allocate
216 * @type_mask: IORESOURCE_* type flags
217 * @alignf: resource alignment function
218 * @alignf_data: data argument for resource alignment function
219 *
220 * Given the PCI bus a device resides on, the size, minimum address,
221 * alignment and type, try to find an acceptable resource allocation
222 * for a specific device resource.
223 */
224int pci_bus_alloc_resource(struct pci_bus *bus, struct resource *res,
225 resource_size_t size, resource_size_t align,
226 resource_size_t min, unsigned long type_mask,
227 resource_size_t (*alignf)(void *,
228 const struct resource *,
229 resource_size_t,
230 resource_size_t),
231 void *alignf_data)
232{
233#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
234 int rc;
235
236 if (res->flags & IORESOURCE_MEM_64) {
237 rc = pci_bus_alloc_from_region(bus, res, size, align, min,
238 type_mask, alignf, alignf_data,
239 &pci_high);
240 if (rc == 0)
241 return 0;
242
243 return pci_bus_alloc_from_region(bus, res, size, align, min,
244 type_mask, alignf, alignf_data,
245 &pci_64_bit);
246 }
247#endif
248
249 return pci_bus_alloc_from_region(bus, res, size, align, min,
250 type_mask, alignf, alignf_data,
251 &pci_32_bit);
252}
253EXPORT_SYMBOL(pci_bus_alloc_resource);
254
255/*
256 * The @idx resource of @dev should be a PCI-PCI bridge window. If this
257 * resource fits inside a window of an upstream bridge, do nothing. If it
258 * overlaps an upstream window but extends outside it, clip the resource so
259 * it fits completely inside.
260 */
261bool pci_bus_clip_resource(struct pci_dev *dev, int idx)
262{
263 struct pci_bus *bus = dev->bus;
264 struct resource *res = &dev->resource[idx];
265 struct resource orig_res = *res;
266 struct resource *r;
267 int i;
268
269 pci_bus_for_each_resource(bus, r, i) {
270 resource_size_t start, end;
271
272 if (!r)
273 continue;
274
275 if (resource_type(res) != resource_type(r))
276 continue;
277
278 start = max(r->start, res->start);
279 end = min(r->end, res->end);
280
281 if (start > end)
282 continue; /* no overlap */
283
284 if (res->start == start && res->end == end)
285 return false; /* no change */
286
287 res->start = start;
288 res->end = end;
289 res->flags &= ~IORESOURCE_UNSET;
290 orig_res.flags &= ~IORESOURCE_UNSET;
291 pci_info(dev, "%pR clipped to %pR\n", &orig_res, res);
292
293 return true;
294 }
295
296 return false;
297}
298
299void __weak pcibios_resource_survey_bus(struct pci_bus *bus) { }
300
301void __weak pcibios_bus_add_device(struct pci_dev *pdev) { }
302
303/**
304 * pci_bus_add_device - start driver for a single device
305 * @dev: device to add
306 *
307 * This adds add sysfs entries and start device drivers
308 */
309void pci_bus_add_device(struct pci_dev *dev)
310{
311 int retval;
312
313 /*
314 * Can not put in pci_device_add yet because resources
315 * are not assigned yet for some devices.
316 */
317 pcibios_bus_add_device(dev);
318 pci_fixup_device(pci_fixup_final, dev);
319 pci_create_sysfs_dev_files(dev);
320 pci_proc_attach_device(dev);
321 pci_bridge_d3_update(dev);
322
323 dev->match_driver = true;
324 retval = device_attach(&dev->dev);
325 if (retval < 0 && retval != -EPROBE_DEFER) {
326 pci_warn(dev, "device attach failed (%d)\n", retval);
327 pci_proc_detach_device(dev);
328 pci_remove_sysfs_dev_files(dev);
329 return;
330 }
331
332 pci_dev_assign_added(dev, true);
333}
334EXPORT_SYMBOL_GPL(pci_bus_add_device);
335
336/**
337 * pci_bus_add_devices - start driver for PCI devices
338 * @bus: bus to check for new devices
339 *
340 * Start driver for PCI devices and add some sysfs entries.
341 */
342void pci_bus_add_devices(const struct pci_bus *bus)
343{
344 struct pci_dev *dev;
345 struct pci_bus *child;
346
347 list_for_each_entry(dev, &bus->devices, bus_list) {
348 /* Skip already-added devices */
349 if (pci_dev_is_added(dev))
350 continue;
351 pci_bus_add_device(dev);
352 }
353
354 list_for_each_entry(dev, &bus->devices, bus_list) {
355 /* Skip if device attach failed */
356 if (!pci_dev_is_added(dev))
357 continue;
358 child = dev->subordinate;
359 if (child)
360 pci_bus_add_devices(child);
361 }
362}
363EXPORT_SYMBOL(pci_bus_add_devices);
364
365/** pci_walk_bus - walk devices on/under bus, calling callback.
366 * @top bus whose devices should be walked
367 * @cb callback to be called for each device found
368 * @userdata arbitrary pointer to be passed to callback.
369 *
370 * Walk the given bus, including any bridged devices
371 * on buses under this bus. Call the provided callback
372 * on each device found.
373 *
374 * We check the return of @cb each time. If it returns anything
375 * other than 0, we break out.
376 *
377 */
378void pci_walk_bus(struct pci_bus *top, int (*cb)(struct pci_dev *, void *),
379 void *userdata)
380{
381 struct pci_dev *dev;
382 struct pci_bus *bus;
383 struct list_head *next;
384 int retval;
385
386 bus = top;
387 down_read(&pci_bus_sem);
388 next = top->devices.next;
389 for (;;) {
390 if (next == &bus->devices) {
391 /* end of this bus, go up or finish */
392 if (bus == top)
393 break;
394 next = bus->self->bus_list.next;
395 bus = bus->self->bus;
396 continue;
397 }
398 dev = list_entry(next, struct pci_dev, bus_list);
399 if (dev->subordinate) {
400 /* this is a pci-pci bridge, do its devices next */
401 next = dev->subordinate->devices.next;
402 bus = dev->subordinate;
403 } else
404 next = dev->bus_list.next;
405
406 retval = cb(dev, userdata);
407 if (retval)
408 break;
409 }
410 up_read(&pci_bus_sem);
411}
412EXPORT_SYMBOL_GPL(pci_walk_bus);
413
414struct pci_bus *pci_bus_get(struct pci_bus *bus)
415{
416 if (bus)
417 get_device(&bus->dev);
418 return bus;
419}
420
421void pci_bus_put(struct pci_bus *bus)
422{
423 if (bus)
424 put_device(&bus->dev);
425}
1/*
2 * drivers/pci/bus.c
3 *
4 * From setup-res.c, by:
5 * Dave Rusling (david.rusling@reo.mts.dec.com)
6 * David Mosberger (davidm@cs.arizona.edu)
7 * David Miller (davem@redhat.com)
8 * Ivan Kokshaysky (ink@jurassic.park.msu.ru)
9 */
10#include <linux/module.h>
11#include <linux/kernel.h>
12#include <linux/pci.h>
13#include <linux/errno.h>
14#include <linux/ioport.h>
15#include <linux/proc_fs.h>
16#include <linux/slab.h>
17
18#include "pci.h"
19
20void pci_add_resource_offset(struct list_head *resources, struct resource *res,
21 resource_size_t offset)
22{
23 struct resource_entry *entry;
24
25 entry = resource_list_create_entry(res, 0);
26 if (!entry) {
27 printk(KERN_ERR "PCI: can't add host bridge window %pR\n", res);
28 return;
29 }
30
31 entry->offset = offset;
32 resource_list_add_tail(entry, resources);
33}
34EXPORT_SYMBOL(pci_add_resource_offset);
35
36void pci_add_resource(struct list_head *resources, struct resource *res)
37{
38 pci_add_resource_offset(resources, res, 0);
39}
40EXPORT_SYMBOL(pci_add_resource);
41
42void pci_free_resource_list(struct list_head *resources)
43{
44 resource_list_free(resources);
45}
46EXPORT_SYMBOL(pci_free_resource_list);
47
48void pci_bus_add_resource(struct pci_bus *bus, struct resource *res,
49 unsigned int flags)
50{
51 struct pci_bus_resource *bus_res;
52
53 bus_res = kzalloc(sizeof(struct pci_bus_resource), GFP_KERNEL);
54 if (!bus_res) {
55 dev_err(&bus->dev, "can't add %pR resource\n", res);
56 return;
57 }
58
59 bus_res->res = res;
60 bus_res->flags = flags;
61 list_add_tail(&bus_res->list, &bus->resources);
62}
63
64struct resource *pci_bus_resource_n(const struct pci_bus *bus, int n)
65{
66 struct pci_bus_resource *bus_res;
67
68 if (n < PCI_BRIDGE_RESOURCE_NUM)
69 return bus->resource[n];
70
71 n -= PCI_BRIDGE_RESOURCE_NUM;
72 list_for_each_entry(bus_res, &bus->resources, list) {
73 if (n-- == 0)
74 return bus_res->res;
75 }
76 return NULL;
77}
78EXPORT_SYMBOL_GPL(pci_bus_resource_n);
79
80void pci_bus_remove_resources(struct pci_bus *bus)
81{
82 int i;
83 struct pci_bus_resource *bus_res, *tmp;
84
85 for (i = 0; i < PCI_BRIDGE_RESOURCE_NUM; i++)
86 bus->resource[i] = NULL;
87
88 list_for_each_entry_safe(bus_res, tmp, &bus->resources, list) {
89 list_del(&bus_res->list);
90 kfree(bus_res);
91 }
92}
93
94static struct pci_bus_region pci_32_bit = {0, 0xffffffffULL};
95#ifdef CONFIG_PCI_BUS_ADDR_T_64BIT
96static struct pci_bus_region pci_64_bit = {0,
97 (pci_bus_addr_t) 0xffffffffffffffffULL};
98static struct pci_bus_region pci_high = {(pci_bus_addr_t) 0x100000000ULL,
99 (pci_bus_addr_t) 0xffffffffffffffffULL};
100#endif
101
102/*
103 * @res contains CPU addresses. Clip it so the corresponding bus addresses
104 * on @bus are entirely within @region. This is used to control the bus
105 * addresses of resources we allocate, e.g., we may need a resource that
106 * can be mapped by a 32-bit BAR.
107 */
108static void pci_clip_resource_to_region(struct pci_bus *bus,
109 struct resource *res,
110 struct pci_bus_region *region)
111{
112 struct pci_bus_region r;
113
114 pcibios_resource_to_bus(bus, &r, res);
115 if (r.start < region->start)
116 r.start = region->start;
117 if (r.end > region->end)
118 r.end = region->end;
119
120 if (r.end < r.start)
121 res->end = res->start - 1;
122 else
123 pcibios_bus_to_resource(bus, res, &r);
124}
125
126static int pci_bus_alloc_from_region(struct pci_bus *bus, struct resource *res,
127 resource_size_t size, resource_size_t align,
128 resource_size_t min, unsigned long type_mask,
129 resource_size_t (*alignf)(void *,
130 const struct resource *,
131 resource_size_t,
132 resource_size_t),
133 void *alignf_data,
134 struct pci_bus_region *region)
135{
136 int i, ret;
137 struct resource *r, avail;
138 resource_size_t max;
139
140 type_mask |= IORESOURCE_TYPE_BITS;
141
142 pci_bus_for_each_resource(bus, r, i) {
143 resource_size_t min_used = min;
144
145 if (!r)
146 continue;
147
148 /* type_mask must match */
149 if ((res->flags ^ r->flags) & type_mask)
150 continue;
151
152 /* We cannot allocate a non-prefetching resource
153 from a pre-fetching area */
154 if ((r->flags & IORESOURCE_PREFETCH) &&
155 !(res->flags & IORESOURCE_PREFETCH))
156 continue;
157
158 avail = *r;
159 pci_clip_resource_to_region(bus, &avail, region);
160
161 /*
162 * "min" is typically PCIBIOS_MIN_IO or PCIBIOS_MIN_MEM to
163 * protect badly documented motherboard resources, but if
164 * this is an already-configured bridge window, its start
165 * overrides "min".
166 */
167 if (avail.start)
168 min_used = avail.start;
169
170 max = avail.end;
171
172 /* Ok, try it out.. */
173 ret = allocate_resource(r, res, size, min_used, max,
174 align, alignf, alignf_data);
175 if (ret == 0)
176 return 0;
177 }
178 return -ENOMEM;
179}
180
181/**
182 * pci_bus_alloc_resource - allocate a resource from a parent bus
183 * @bus: PCI bus
184 * @res: resource to allocate
185 * @size: size of resource to allocate
186 * @align: alignment of resource to allocate
187 * @min: minimum /proc/iomem address to allocate
188 * @type_mask: IORESOURCE_* type flags
189 * @alignf: resource alignment function
190 * @alignf_data: data argument for resource alignment function
191 *
192 * Given the PCI bus a device resides on, the size, minimum address,
193 * alignment and type, try to find an acceptable resource allocation
194 * for a specific device resource.
195 */
196int pci_bus_alloc_resource(struct pci_bus *bus, struct resource *res,
197 resource_size_t size, resource_size_t align,
198 resource_size_t min, unsigned long type_mask,
199 resource_size_t (*alignf)(void *,
200 const struct resource *,
201 resource_size_t,
202 resource_size_t),
203 void *alignf_data)
204{
205#ifdef CONFIG_PCI_BUS_ADDR_T_64BIT
206 int rc;
207
208 if (res->flags & IORESOURCE_MEM_64) {
209 rc = pci_bus_alloc_from_region(bus, res, size, align, min,
210 type_mask, alignf, alignf_data,
211 &pci_high);
212 if (rc == 0)
213 return 0;
214
215 return pci_bus_alloc_from_region(bus, res, size, align, min,
216 type_mask, alignf, alignf_data,
217 &pci_64_bit);
218 }
219#endif
220
221 return pci_bus_alloc_from_region(bus, res, size, align, min,
222 type_mask, alignf, alignf_data,
223 &pci_32_bit);
224}
225EXPORT_SYMBOL(pci_bus_alloc_resource);
226
227/*
228 * The @idx resource of @dev should be a PCI-PCI bridge window. If this
229 * resource fits inside a window of an upstream bridge, do nothing. If it
230 * overlaps an upstream window but extends outside it, clip the resource so
231 * it fits completely inside.
232 */
233bool pci_bus_clip_resource(struct pci_dev *dev, int idx)
234{
235 struct pci_bus *bus = dev->bus;
236 struct resource *res = &dev->resource[idx];
237 struct resource orig_res = *res;
238 struct resource *r;
239 int i;
240
241 pci_bus_for_each_resource(bus, r, i) {
242 resource_size_t start, end;
243
244 if (!r)
245 continue;
246
247 if (resource_type(res) != resource_type(r))
248 continue;
249
250 start = max(r->start, res->start);
251 end = min(r->end, res->end);
252
253 if (start > end)
254 continue; /* no overlap */
255
256 if (res->start == start && res->end == end)
257 return false; /* no change */
258
259 res->start = start;
260 res->end = end;
261 res->flags &= ~IORESOURCE_UNSET;
262 orig_res.flags &= ~IORESOURCE_UNSET;
263 dev_printk(KERN_DEBUG, &dev->dev, "%pR clipped to %pR\n",
264 &orig_res, res);
265
266 return true;
267 }
268
269 return false;
270}
271
272void __weak pcibios_resource_survey_bus(struct pci_bus *bus) { }
273
274void __weak pcibios_bus_add_device(struct pci_dev *pdev) { }
275
276/**
277 * pci_bus_add_device - start driver for a single device
278 * @dev: device to add
279 *
280 * This adds add sysfs entries and start device drivers
281 */
282void pci_bus_add_device(struct pci_dev *dev)
283{
284 int retval;
285
286 /*
287 * Can not put in pci_device_add yet because resources
288 * are not assigned yet for some devices.
289 */
290 pcibios_bus_add_device(dev);
291 pci_fixup_device(pci_fixup_final, dev);
292 pci_create_sysfs_dev_files(dev);
293 pci_proc_attach_device(dev);
294
295 dev->match_driver = true;
296 retval = device_attach(&dev->dev);
297 if (retval < 0 && retval != -EPROBE_DEFER) {
298 dev_warn(&dev->dev, "device attach failed (%d)\n", retval);
299 pci_proc_detach_device(dev);
300 pci_remove_sysfs_dev_files(dev);
301 return;
302 }
303
304 dev->is_added = 1;
305}
306EXPORT_SYMBOL_GPL(pci_bus_add_device);
307
308/**
309 * pci_bus_add_devices - start driver for PCI devices
310 * @bus: bus to check for new devices
311 *
312 * Start driver for PCI devices and add some sysfs entries.
313 */
314void pci_bus_add_devices(const struct pci_bus *bus)
315{
316 struct pci_dev *dev;
317 struct pci_bus *child;
318
319 list_for_each_entry(dev, &bus->devices, bus_list) {
320 /* Skip already-added devices */
321 if (dev->is_added)
322 continue;
323 pci_bus_add_device(dev);
324 }
325
326 list_for_each_entry(dev, &bus->devices, bus_list) {
327 /* Skip if device attach failed */
328 if (!dev->is_added)
329 continue;
330 child = dev->subordinate;
331 if (child)
332 pci_bus_add_devices(child);
333 }
334}
335EXPORT_SYMBOL(pci_bus_add_devices);
336
337/** pci_walk_bus - walk devices on/under bus, calling callback.
338 * @top bus whose devices should be walked
339 * @cb callback to be called for each device found
340 * @userdata arbitrary pointer to be passed to callback.
341 *
342 * Walk the given bus, including any bridged devices
343 * on buses under this bus. Call the provided callback
344 * on each device found.
345 *
346 * We check the return of @cb each time. If it returns anything
347 * other than 0, we break out.
348 *
349 */
350void pci_walk_bus(struct pci_bus *top, int (*cb)(struct pci_dev *, void *),
351 void *userdata)
352{
353 struct pci_dev *dev;
354 struct pci_bus *bus;
355 struct list_head *next;
356 int retval;
357
358 bus = top;
359 down_read(&pci_bus_sem);
360 next = top->devices.next;
361 for (;;) {
362 if (next == &bus->devices) {
363 /* end of this bus, go up or finish */
364 if (bus == top)
365 break;
366 next = bus->self->bus_list.next;
367 bus = bus->self->bus;
368 continue;
369 }
370 dev = list_entry(next, struct pci_dev, bus_list);
371 if (dev->subordinate) {
372 /* this is a pci-pci bridge, do its devices next */
373 next = dev->subordinate->devices.next;
374 bus = dev->subordinate;
375 } else
376 next = dev->bus_list.next;
377
378 retval = cb(dev, userdata);
379 if (retval)
380 break;
381 }
382 up_read(&pci_bus_sem);
383}
384EXPORT_SYMBOL_GPL(pci_walk_bus);
385
386struct pci_bus *pci_bus_get(struct pci_bus *bus)
387{
388 if (bus)
389 get_device(&bus->dev);
390 return bus;
391}
392EXPORT_SYMBOL(pci_bus_get);
393
394void pci_bus_put(struct pci_bus *bus)
395{
396 if (bus)
397 put_device(&bus->dev);
398}
399EXPORT_SYMBOL(pci_bus_put);
400