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v5.4
  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}
v3.15
 
  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/init.h>
 17#include <linux/slab.h>
 18
 19#include "pci.h"
 20
 21void pci_add_resource_offset(struct list_head *resources, struct resource *res,
 22			     resource_size_t offset)
 23{
 24	struct pci_host_bridge_window *window;
 25
 26	window = kzalloc(sizeof(struct pci_host_bridge_window), GFP_KERNEL);
 27	if (!window) {
 28		printk(KERN_ERR "PCI: can't add host bridge window %pR\n", res);
 29		return;
 30	}
 31
 32	window->res = res;
 33	window->offset = offset;
 34	list_add_tail(&window->list, resources);
 35}
 36EXPORT_SYMBOL(pci_add_resource_offset);
 37
 38void pci_add_resource(struct list_head *resources, struct resource *res)
 39{
 40	pci_add_resource_offset(resources, res, 0);
 41}
 42EXPORT_SYMBOL(pci_add_resource);
 43
 44void pci_free_resource_list(struct list_head *resources)
 45{
 46	struct pci_host_bridge_window *window, *tmp;
 47
 48	list_for_each_entry_safe(window, tmp, resources, list) {
 49		list_del(&window->list);
 50		kfree(window);
 51	}
 52}
 53EXPORT_SYMBOL(pci_free_resource_list);
 54
 55void pci_bus_add_resource(struct pci_bus *bus, struct resource *res,
 56			  unsigned int flags)
 57{
 58	struct pci_bus_resource *bus_res;
 59
 60	bus_res = kzalloc(sizeof(struct pci_bus_resource), GFP_KERNEL);
 61	if (!bus_res) {
 62		dev_err(&bus->dev, "can't add %pR resource\n", res);
 63		return;
 64	}
 65
 66	bus_res->res = res;
 67	bus_res->flags = flags;
 68	list_add_tail(&bus_res->list, &bus->resources);
 69}
 70
 71struct resource *pci_bus_resource_n(const struct pci_bus *bus, int n)
 72{
 73	struct pci_bus_resource *bus_res;
 74
 75	if (n < PCI_BRIDGE_RESOURCE_NUM)
 76		return bus->resource[n];
 77
 78	n -= PCI_BRIDGE_RESOURCE_NUM;
 79	list_for_each_entry(bus_res, &bus->resources, list) {
 80		if (n-- == 0)
 81			return bus_res->res;
 82	}
 83	return NULL;
 84}
 85EXPORT_SYMBOL_GPL(pci_bus_resource_n);
 86
 87void pci_bus_remove_resources(struct pci_bus *bus)
 88{
 89	int i;
 90	struct pci_bus_resource *bus_res, *tmp;
 91
 92	for (i = 0; i < PCI_BRIDGE_RESOURCE_NUM; i++)
 93		bus->resource[i] = NULL;
 94
 95	list_for_each_entry_safe(bus_res, tmp, &bus->resources, list) {
 96		list_del(&bus_res->list);
 97		kfree(bus_res);
 98	}
 99}
100
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
101static struct pci_bus_region pci_32_bit = {0, 0xffffffffULL};
102#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
103static struct pci_bus_region pci_64_bit = {0,
104				(dma_addr_t) 0xffffffffffffffffULL};
105static struct pci_bus_region pci_high = {(dma_addr_t) 0x100000000ULL,
106				(dma_addr_t) 0xffffffffffffffffULL};
107#endif
108
109/*
110 * @res contains CPU addresses.  Clip it so the corresponding bus addresses
111 * on @bus are entirely within @region.  This is used to control the bus
112 * addresses of resources we allocate, e.g., we may need a resource that
113 * can be mapped by a 32-bit BAR.
114 */
115static void pci_clip_resource_to_region(struct pci_bus *bus,
116					struct resource *res,
117					struct pci_bus_region *region)
118{
119	struct pci_bus_region r;
120
121	pcibios_resource_to_bus(bus, &r, res);
122	if (r.start < region->start)
123		r.start = region->start;
124	if (r.end > region->end)
125		r.end = region->end;
126
127	if (r.end < r.start)
128		res->end = res->start - 1;
129	else
130		pcibios_bus_to_resource(bus, res, &r);
131}
132
133static int pci_bus_alloc_from_region(struct pci_bus *bus, struct resource *res,
134		resource_size_t size, resource_size_t align,
135		resource_size_t min, unsigned long type_mask,
136		resource_size_t (*alignf)(void *,
137					  const struct resource *,
138					  resource_size_t,
139					  resource_size_t),
140		void *alignf_data,
141		struct pci_bus_region *region)
142{
143	int i, ret;
144	struct resource *r, avail;
145	resource_size_t max;
146
147	type_mask |= IORESOURCE_TYPE_BITS;
148
149	pci_bus_for_each_resource(bus, r, i) {
 
 
150		if (!r)
151			continue;
152
153		/* type_mask must match */
154		if ((res->flags ^ r->flags) & type_mask)
155			continue;
156
157		/* We cannot allocate a non-prefetching resource
158		   from a pre-fetching area */
159		if ((r->flags & IORESOURCE_PREFETCH) &&
160		    !(res->flags & IORESOURCE_PREFETCH))
161			continue;
162
163		avail = *r;
164		pci_clip_resource_to_region(bus, &avail, region);
165
166		/*
167		 * "min" is typically PCIBIOS_MIN_IO or PCIBIOS_MIN_MEM to
168		 * protect badly documented motherboard resources, but if
169		 * this is an already-configured bridge window, its start
170		 * overrides "min".
171		 */
172		if (avail.start)
173			min = avail.start;
174
175		max = avail.end;
176
177		/* Ok, try it out.. */
178		ret = allocate_resource(r, res, size, min, max,
179					align, alignf, alignf_data);
180		if (ret == 0)
181			return 0;
182	}
183	return -ENOMEM;
184}
185
186/**
187 * pci_bus_alloc_resource - allocate a resource from a parent bus
188 * @bus: PCI bus
189 * @res: resource to allocate
190 * @size: size of resource to allocate
191 * @align: alignment of resource to allocate
192 * @min: minimum /proc/iomem address to allocate
193 * @type_mask: IORESOURCE_* type flags
194 * @alignf: resource alignment function
195 * @alignf_data: data argument for resource alignment function
196 *
197 * Given the PCI bus a device resides on, the size, minimum address,
198 * alignment and type, try to find an acceptable resource allocation
199 * for a specific device resource.
200 */
201int pci_bus_alloc_resource(struct pci_bus *bus, struct resource *res,
202		resource_size_t size, resource_size_t align,
203		resource_size_t min, unsigned long type_mask,
204		resource_size_t (*alignf)(void *,
205					  const struct resource *,
206					  resource_size_t,
207					  resource_size_t),
208		void *alignf_data)
209{
210#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
211	int rc;
212
213	if (res->flags & IORESOURCE_MEM_64) {
214		rc = pci_bus_alloc_from_region(bus, res, size, align, min,
215					       type_mask, alignf, alignf_data,
216					       &pci_high);
217		if (rc == 0)
218			return 0;
219
220		return pci_bus_alloc_from_region(bus, res, size, align, min,
221						 type_mask, alignf, alignf_data,
222						 &pci_64_bit);
223	}
224#endif
225
226	return pci_bus_alloc_from_region(bus, res, size, align, min,
227					 type_mask, alignf, alignf_data,
228					 &pci_32_bit);
229}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
230
231void __weak pcibios_resource_survey_bus(struct pci_bus *bus) { }
232
 
 
233/**
234 * pci_bus_add_device - start driver for a single device
235 * @dev: device to add
236 *
237 * This adds add sysfs entries and start device drivers
238 */
239int pci_bus_add_device(struct pci_dev *dev)
240{
241	int retval;
242
243	/*
244	 * Can not put in pci_device_add yet because resources
245	 * are not assigned yet for some devices.
246	 */
 
247	pci_fixup_device(pci_fixup_final, dev);
248	pci_create_sysfs_dev_files(dev);
249	pci_proc_attach_device(dev);
 
250
251	dev->match_driver = true;
252	retval = device_attach(&dev->dev);
253	WARN_ON(retval < 0);
254
255	dev->is_added = 1;
 
 
 
256
257	return 0;
258}
 
259
260/**
261 * pci_bus_add_devices - start driver for PCI devices
262 * @bus: bus to check for new devices
263 *
264 * Start driver for PCI devices and add some sysfs entries.
265 */
266void pci_bus_add_devices(const struct pci_bus *bus)
267{
268	struct pci_dev *dev;
269	struct pci_bus *child;
270	int retval;
271
272	list_for_each_entry(dev, &bus->devices, bus_list) {
273		/* Skip already-added devices */
274		if (dev->is_added)
275			continue;
276		retval = pci_bus_add_device(dev);
277		if (retval)
278			dev_err(&dev->dev, "Error adding device (%d)\n",
279				retval);
280	}
281
282	list_for_each_entry(dev, &bus->devices, bus_list) {
283		BUG_ON(!dev->is_added);
 
 
284		child = dev->subordinate;
285		if (child)
286			pci_bus_add_devices(child);
287	}
288}
 
289
290/** pci_walk_bus - walk devices on/under bus, calling callback.
291 *  @top      bus whose devices should be walked
292 *  @cb       callback to be called for each device found
293 *  @userdata arbitrary pointer to be passed to callback.
294 *
295 *  Walk the given bus, including any bridged devices
296 *  on buses under this bus.  Call the provided callback
297 *  on each device found.
298 *
299 *  We check the return of @cb each time. If it returns anything
300 *  other than 0, we break out.
301 *
302 */
303void pci_walk_bus(struct pci_bus *top, int (*cb)(struct pci_dev *, void *),
304		  void *userdata)
305{
306	struct pci_dev *dev;
307	struct pci_bus *bus;
308	struct list_head *next;
309	int retval;
310
311	bus = top;
312	down_read(&pci_bus_sem);
313	next = top->devices.next;
314	for (;;) {
315		if (next == &bus->devices) {
316			/* end of this bus, go up or finish */
317			if (bus == top)
318				break;
319			next = bus->self->bus_list.next;
320			bus = bus->self->bus;
321			continue;
322		}
323		dev = list_entry(next, struct pci_dev, bus_list);
324		if (dev->subordinate) {
325			/* this is a pci-pci bridge, do its devices next */
326			next = dev->subordinate->devices.next;
327			bus = dev->subordinate;
328		} else
329			next = dev->bus_list.next;
330
331		retval = cb(dev, userdata);
332		if (retval)
333			break;
334	}
335	up_read(&pci_bus_sem);
336}
337EXPORT_SYMBOL_GPL(pci_walk_bus);
338
339struct pci_bus *pci_bus_get(struct pci_bus *bus)
340{
341	if (bus)
342		get_device(&bus->dev);
343	return bus;
344}
345EXPORT_SYMBOL(pci_bus_get);
346
347void pci_bus_put(struct pci_bus *bus)
348{
349	if (bus)
350		put_device(&bus->dev);
351}
352EXPORT_SYMBOL(pci_bus_put);
353
354EXPORT_SYMBOL(pci_bus_alloc_resource);
355EXPORT_SYMBOL_GPL(pci_bus_add_device);
356EXPORT_SYMBOL(pci_bus_add_devices);