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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}
v3.5.6
 
  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
 91	for (i = 0; i < PCI_BRIDGE_RESOURCE_NUM; i++)
 92		bus->resource[i] = NULL;
 93
 94	pci_free_resource_list(&bus->resources);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 95}
 96
 97/**
 98 * pci_bus_alloc_resource - allocate a resource from a parent bus
 99 * @bus: PCI bus
100 * @res: resource to allocate
101 * @size: size of resource to allocate
102 * @align: alignment of resource to allocate
103 * @min: minimum /proc/iomem address to allocate
104 * @type_mask: IORESOURCE_* type flags
105 * @alignf: resource alignment function
106 * @alignf_data: data argument for resource alignment function
107 *
108 * Given the PCI bus a device resides on, the size, minimum address,
109 * alignment and type, try to find an acceptable resource allocation
110 * for a specific device resource.
111 */
112int
113pci_bus_alloc_resource(struct pci_bus *bus, struct resource *res,
114		resource_size_t size, resource_size_t align,
115		resource_size_t min, unsigned int type_mask,
116		resource_size_t (*alignf)(void *,
117					  const struct resource *,
118					  resource_size_t,
119					  resource_size_t),
120		void *alignf_data)
121{
122	int i, ret = -ENOMEM;
123	struct resource *r;
124	resource_size_t max = -1;
 
 
 
 
 
 
 
 
 
 
 
 
125
126	type_mask |= IORESOURCE_IO | IORESOURCE_MEM;
 
 
 
 
127
128	/* don't allocate too high if the pref mem doesn't support 64bit*/
129	if (!(res->flags & IORESOURCE_MEM_64))
130		max = PCIBIOS_MAX_MEM_32;
 
 
 
 
 
 
 
 
 
 
131
132	pci_bus_for_each_resource(bus, r, i) {
 
 
133		if (!r)
134			continue;
135
136		/* type_mask must match */
137		if ((res->flags ^ r->flags) & type_mask)
138			continue;
139
140		/* We cannot allocate a non-prefetching resource
141		   from a pre-fetching area */
142		if ((r->flags & IORESOURCE_PREFETCH) &&
143		    !(res->flags & IORESOURCE_PREFETCH))
144			continue;
 
 
 
 
 
 
 
 
 
145
146		/* Ok, try it out.. */
147		ret = allocate_resource(r, res, size,
148					r->start ? : min,
149					max, align,
150					alignf, alignf_data);
151		if (ret == 0)
152			break;
153	}
154	return ret;
 
155}
156
 
 
 
 
157/**
158 * pci_bus_add_device - add a single device
159 * @dev: device to add
160 *
161 * This adds a single pci device to the global
162 * device list and adds sysfs and procfs entries
163 */
164int pci_bus_add_device(struct pci_dev *dev)
165{
166	int retval;
167	retval = device_add(&dev->dev);
168	if (retval)
169		return retval;
170
171	dev->is_added = 1;
 
 
 
 
 
 
172	pci_proc_attach_device(dev);
173	pci_create_sysfs_dev_files(dev);
174	return 0;
175}
176
177/**
178 * pci_bus_add_child - add a child bus
179 * @bus: bus to add
180 *
181 * This adds sysfs entries for a single bus
182 */
183int pci_bus_add_child(struct pci_bus *bus)
184{
185	int retval;
186
187	if (bus->bridge)
188		bus->dev.parent = bus->bridge;
189
190	retval = device_register(&bus->dev);
191	if (retval)
192		return retval;
193
194	bus->is_added = 1;
195
196	/* Create legacy_io and legacy_mem files for this bus */
197	pci_create_legacy_files(bus);
198
199	return retval;
200}
 
201
202/**
203 * pci_bus_add_devices - insert newly discovered PCI devices
204 * @bus: bus to check for new devices
205 *
206 * Add newly discovered PCI devices (which are on the bus->devices
207 * list) to the global PCI device list, add the sysfs and procfs
208 * entries.  Where a bridge is found, add the discovered bus to
209 * the parents list of child buses, and recurse (breadth-first
210 * to be compatible with 2.4)
211 *
212 * Call hotplug for each new devices.
213 */
214void pci_bus_add_devices(const struct pci_bus *bus)
215{
216	struct pci_dev *dev;
217	struct pci_bus *child;
218	int retval;
219
220	list_for_each_entry(dev, &bus->devices, bus_list) {
221		/* Skip already-added devices */
222		if (dev->is_added)
223			continue;
224		retval = pci_bus_add_device(dev);
225		if (retval)
226			dev_err(&dev->dev, "Error adding device, continuing\n");
227	}
228
229	list_for_each_entry(dev, &bus->devices, bus_list) {
230		BUG_ON(!dev->is_added);
231
 
232		child = dev->subordinate;
233		/*
234		 * If there is an unattached subordinate bus, attach
235		 * it and then scan for unattached PCI devices.
236		 */
237		if (!child)
238			continue;
239		if (list_empty(&child->node)) {
240			down_write(&pci_bus_sem);
241			list_add_tail(&child->node, &dev->bus->children);
242			up_write(&pci_bus_sem);
243		}
244		pci_bus_add_devices(child);
245
246		/*
247		 * register the bus with sysfs as the parent is now
248		 * properly registered.
249		 */
250		if (child->is_added)
251			continue;
252		retval = pci_bus_add_child(child);
253		if (retval)
254			dev_err(&dev->dev, "Error adding bus, continuing\n");
255	}
256}
257
258void pci_enable_bridges(struct pci_bus *bus)
259{
260	struct pci_dev *dev;
261	int retval;
262
263	list_for_each_entry(dev, &bus->devices, bus_list) {
264		if (dev->subordinate) {
265			if (!pci_is_enabled(dev)) {
266				retval = pci_enable_device(dev);
267				if (retval)
268					dev_err(&dev->dev, "Error enabling bridge (%d), continuing\n", retval);
269				pci_set_master(dev);
270			}
271			pci_enable_bridges(dev->subordinate);
272		}
273	}
274}
 
275
276/** pci_walk_bus - walk devices on/under bus, calling callback.
277 *  @top      bus whose devices should be walked
278 *  @cb       callback to be called for each device found
279 *  @userdata arbitrary pointer to be passed to callback.
280 *
281 *  Walk the given bus, including any bridged devices
282 *  on buses under this bus.  Call the provided callback
283 *  on each device found.
284 *
285 *  We check the return of @cb each time. If it returns anything
286 *  other than 0, we break out.
287 *
288 */
289void pci_walk_bus(struct pci_bus *top, int (*cb)(struct pci_dev *, void *),
290		  void *userdata)
291{
292	struct pci_dev *dev;
293	struct pci_bus *bus;
294	struct list_head *next;
295	int retval;
296
297	bus = top;
298	down_read(&pci_bus_sem);
299	next = top->devices.next;
300	for (;;) {
301		if (next == &bus->devices) {
302			/* end of this bus, go up or finish */
303			if (bus == top)
304				break;
305			next = bus->self->bus_list.next;
306			bus = bus->self->bus;
307			continue;
308		}
309		dev = list_entry(next, struct pci_dev, bus_list);
310		if (dev->subordinate) {
311			/* this is a pci-pci bridge, do its devices next */
312			next = dev->subordinate->devices.next;
313			bus = dev->subordinate;
314		} else
315			next = dev->bus_list.next;
316
317		/* Run device routines with the device locked */
318		device_lock(&dev->dev);
319		retval = cb(dev, userdata);
320		device_unlock(&dev->dev);
321		if (retval)
322			break;
323	}
324	up_read(&pci_bus_sem);
325}
326EXPORT_SYMBOL_GPL(pci_walk_bus);
327
328EXPORT_SYMBOL(pci_bus_alloc_resource);
329EXPORT_SYMBOL_GPL(pci_bus_add_device);
330EXPORT_SYMBOL(pci_bus_add_devices);
331EXPORT_SYMBOL(pci_enable_bridges);