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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
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);