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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
94int devm_request_pci_bus_resources(struct device *dev,
95 struct list_head *resources)
96{
97 struct resource_entry *win;
98 struct resource *parent, *res;
99 int err;
100
101 resource_list_for_each_entry(win, resources) {
102 res = win->res;
103 switch (resource_type(res)) {
104 case IORESOURCE_IO:
105 parent = &ioport_resource;
106 break;
107 case IORESOURCE_MEM:
108 parent = &iomem_resource;
109 break;
110 default:
111 continue;
112 }
113
114 err = devm_request_resource(dev, parent, res);
115 if (err)
116 return err;
117 }
118
119 return 0;
120}
121EXPORT_SYMBOL_GPL(devm_request_pci_bus_resources);
122
123static struct pci_bus_region pci_32_bit = {0, 0xffffffffULL};
124#ifdef CONFIG_PCI_BUS_ADDR_T_64BIT
125static struct pci_bus_region pci_64_bit = {0,
126 (pci_bus_addr_t) 0xffffffffffffffffULL};
127static struct pci_bus_region pci_high = {(pci_bus_addr_t) 0x100000000ULL,
128 (pci_bus_addr_t) 0xffffffffffffffffULL};
129#endif
130
131/*
132 * @res contains CPU addresses. Clip it so the corresponding bus addresses
133 * on @bus are entirely within @region. This is used to control the bus
134 * addresses of resources we allocate, e.g., we may need a resource that
135 * can be mapped by a 32-bit BAR.
136 */
137static void pci_clip_resource_to_region(struct pci_bus *bus,
138 struct resource *res,
139 struct pci_bus_region *region)
140{
141 struct pci_bus_region r;
142
143 pcibios_resource_to_bus(bus, &r, res);
144 if (r.start < region->start)
145 r.start = region->start;
146 if (r.end > region->end)
147 r.end = region->end;
148
149 if (r.end < r.start)
150 res->end = res->start - 1;
151 else
152 pcibios_bus_to_resource(bus, res, &r);
153}
154
155static int pci_bus_alloc_from_region(struct pci_bus *bus, struct resource *res,
156 resource_size_t size, resource_size_t align,
157 resource_size_t min, unsigned long type_mask,
158 resource_size_t (*alignf)(void *,
159 const struct resource *,
160 resource_size_t,
161 resource_size_t),
162 void *alignf_data,
163 struct pci_bus_region *region)
164{
165 int i, ret;
166 struct resource *r, avail;
167 resource_size_t max;
168
169 type_mask |= IORESOURCE_TYPE_BITS;
170
171 pci_bus_for_each_resource(bus, r, i) {
172 resource_size_t min_used = min;
173
174 if (!r)
175 continue;
176
177 /* type_mask must match */
178 if ((res->flags ^ r->flags) & type_mask)
179 continue;
180
181 /* We cannot allocate a non-prefetching resource
182 from a pre-fetching area */
183 if ((r->flags & IORESOURCE_PREFETCH) &&
184 !(res->flags & IORESOURCE_PREFETCH))
185 continue;
186
187 avail = *r;
188 pci_clip_resource_to_region(bus, &avail, region);
189
190 /*
191 * "min" is typically PCIBIOS_MIN_IO or PCIBIOS_MIN_MEM to
192 * protect badly documented motherboard resources, but if
193 * this is an already-configured bridge window, its start
194 * overrides "min".
195 */
196 if (avail.start)
197 min_used = avail.start;
198
199 max = avail.end;
200
201 /* Ok, try it out.. */
202 ret = allocate_resource(r, res, size, min_used, max,
203 align, alignf, alignf_data);
204 if (ret == 0)
205 return 0;
206 }
207 return -ENOMEM;
208}
209
210/**
211 * pci_bus_alloc_resource - allocate a resource from a parent bus
212 * @bus: PCI bus
213 * @res: resource to allocate
214 * @size: size of resource to allocate
215 * @align: alignment of resource to allocate
216 * @min: minimum /proc/iomem address to allocate
217 * @type_mask: IORESOURCE_* type flags
218 * @alignf: resource alignment function
219 * @alignf_data: data argument for resource alignment function
220 *
221 * Given the PCI bus a device resides on, the size, minimum address,
222 * alignment and type, try to find an acceptable resource allocation
223 * for a specific device resource.
224 */
225int pci_bus_alloc_resource(struct pci_bus *bus, struct resource *res,
226 resource_size_t size, resource_size_t align,
227 resource_size_t min, unsigned long type_mask,
228 resource_size_t (*alignf)(void *,
229 const struct resource *,
230 resource_size_t,
231 resource_size_t),
232 void *alignf_data)
233{
234#ifdef CONFIG_PCI_BUS_ADDR_T_64BIT
235 int rc;
236
237 if (res->flags & IORESOURCE_MEM_64) {
238 rc = pci_bus_alloc_from_region(bus, res, size, align, min,
239 type_mask, alignf, alignf_data,
240 &pci_high);
241 if (rc == 0)
242 return 0;
243
244 return pci_bus_alloc_from_region(bus, res, size, align, min,
245 type_mask, alignf, alignf_data,
246 &pci_64_bit);
247 }
248#endif
249
250 return pci_bus_alloc_from_region(bus, res, size, align, min,
251 type_mask, alignf, alignf_data,
252 &pci_32_bit);
253}
254EXPORT_SYMBOL(pci_bus_alloc_resource);
255
256/*
257 * The @idx resource of @dev should be a PCI-PCI bridge window. If this
258 * resource fits inside a window of an upstream bridge, do nothing. If it
259 * overlaps an upstream window but extends outside it, clip the resource so
260 * it fits completely inside.
261 */
262bool pci_bus_clip_resource(struct pci_dev *dev, int idx)
263{
264 struct pci_bus *bus = dev->bus;
265 struct resource *res = &dev->resource[idx];
266 struct resource orig_res = *res;
267 struct resource *r;
268 int i;
269
270 pci_bus_for_each_resource(bus, r, i) {
271 resource_size_t start, end;
272
273 if (!r)
274 continue;
275
276 if (resource_type(res) != resource_type(r))
277 continue;
278
279 start = max(r->start, res->start);
280 end = min(r->end, res->end);
281
282 if (start > end)
283 continue; /* no overlap */
284
285 if (res->start == start && res->end == end)
286 return false; /* no change */
287
288 res->start = start;
289 res->end = end;
290 res->flags &= ~IORESOURCE_UNSET;
291 orig_res.flags &= ~IORESOURCE_UNSET;
292 dev_printk(KERN_DEBUG, &dev->dev, "%pR clipped to %pR\n",
293 &orig_res, res);
294
295 return true;
296 }
297
298 return false;
299}
300
301void __weak pcibios_resource_survey_bus(struct pci_bus *bus) { }
302
303void __weak pcibios_bus_add_device(struct pci_dev *pdev) { }
304
305/**
306 * pci_bus_add_device - start driver for a single device
307 * @dev: device to add
308 *
309 * This adds add sysfs entries and start device drivers
310 */
311void pci_bus_add_device(struct pci_dev *dev)
312{
313 int retval;
314
315 /*
316 * Can not put in pci_device_add yet because resources
317 * are not assigned yet for some devices.
318 */
319 pcibios_bus_add_device(dev);
320 pci_fixup_device(pci_fixup_final, dev);
321 pci_create_sysfs_dev_files(dev);
322 pci_proc_attach_device(dev);
323 pci_bridge_d3_update(dev);
324
325 dev->match_driver = true;
326 retval = device_attach(&dev->dev);
327 if (retval < 0 && retval != -EPROBE_DEFER) {
328 dev_warn(&dev->dev, "device attach failed (%d)\n", retval);
329 pci_proc_detach_device(dev);
330 pci_remove_sysfs_dev_files(dev);
331 return;
332 }
333
334 dev->is_added = 1;
335}
336EXPORT_SYMBOL_GPL(pci_bus_add_device);
337
338/**
339 * pci_bus_add_devices - start driver for PCI devices
340 * @bus: bus to check for new devices
341 *
342 * Start driver for PCI devices and add some sysfs entries.
343 */
344void pci_bus_add_devices(const struct pci_bus *bus)
345{
346 struct pci_dev *dev;
347 struct pci_bus *child;
348
349 list_for_each_entry(dev, &bus->devices, bus_list) {
350 /* Skip already-added devices */
351 if (dev->is_added)
352 continue;
353 pci_bus_add_device(dev);
354 }
355
356 list_for_each_entry(dev, &bus->devices, bus_list) {
357 /* Skip if device attach failed */
358 if (!dev->is_added)
359 continue;
360 child = dev->subordinate;
361 if (child)
362 pci_bus_add_devices(child);
363 }
364}
365EXPORT_SYMBOL(pci_bus_add_devices);
366
367/** pci_walk_bus - walk devices on/under bus, calling callback.
368 * @top bus whose devices should be walked
369 * @cb callback to be called for each device found
370 * @userdata arbitrary pointer to be passed to callback.
371 *
372 * Walk the given bus, including any bridged devices
373 * on buses under this bus. Call the provided callback
374 * on each device found.
375 *
376 * We check the return of @cb each time. If it returns anything
377 * other than 0, we break out.
378 *
379 */
380void pci_walk_bus(struct pci_bus *top, int (*cb)(struct pci_dev *, void *),
381 void *userdata)
382{
383 struct pci_dev *dev;
384 struct pci_bus *bus;
385 struct list_head *next;
386 int retval;
387
388 bus = top;
389 down_read(&pci_bus_sem);
390 next = top->devices.next;
391 for (;;) {
392 if (next == &bus->devices) {
393 /* end of this bus, go up or finish */
394 if (bus == top)
395 break;
396 next = bus->self->bus_list.next;
397 bus = bus->self->bus;
398 continue;
399 }
400 dev = list_entry(next, struct pci_dev, bus_list);
401 if (dev->subordinate) {
402 /* this is a pci-pci bridge, do its devices next */
403 next = dev->subordinate->devices.next;
404 bus = dev->subordinate;
405 } else
406 next = dev->bus_list.next;
407
408 retval = cb(dev, userdata);
409 if (retval)
410 break;
411 }
412 up_read(&pci_bus_sem);
413}
414EXPORT_SYMBOL_GPL(pci_walk_bus);
415
416struct pci_bus *pci_bus_get(struct pci_bus *bus)
417{
418 if (bus)
419 get_device(&bus->dev);
420 return bus;
421}
422EXPORT_SYMBOL(pci_bus_get);
423
424void pci_bus_put(struct pci_bus *bus)
425{
426 if (bus)
427 put_device(&bus->dev);
428}
429EXPORT_SYMBOL(pci_bus_put);