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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/of.h>
15#include <linux/of_platform.h>
16#include <linux/platform_device.h>
17#include <linux/proc_fs.h>
18#include <linux/slab.h>
19
20#include "pci.h"
21
22/*
23 * The first PCI_BRIDGE_RESOURCE_NUM PCI bus resources (those that correspond
24 * to P2P or CardBus bridge windows) go in a table. Additional ones (for
25 * buses below host bridges or subtractive decode bridges) go in the list.
26 * Use pci_bus_for_each_resource() to iterate through all the resources.
27 */
28
29struct pci_bus_resource {
30 struct list_head list;
31 struct resource *res;
32};
33
34void pci_add_resource_offset(struct list_head *resources, struct resource *res,
35 resource_size_t offset)
36{
37 struct resource_entry *entry;
38
39 entry = resource_list_create_entry(res, 0);
40 if (!entry) {
41 pr_err("PCI: can't add host bridge window %pR\n", res);
42 return;
43 }
44
45 entry->offset = offset;
46 resource_list_add_tail(entry, resources);
47}
48EXPORT_SYMBOL(pci_add_resource_offset);
49
50void pci_add_resource(struct list_head *resources, struct resource *res)
51{
52 pci_add_resource_offset(resources, res, 0);
53}
54EXPORT_SYMBOL(pci_add_resource);
55
56void pci_free_resource_list(struct list_head *resources)
57{
58 resource_list_free(resources);
59}
60EXPORT_SYMBOL(pci_free_resource_list);
61
62void pci_bus_add_resource(struct pci_bus *bus, struct resource *res)
63{
64 struct pci_bus_resource *bus_res;
65
66 bus_res = kzalloc(sizeof(struct pci_bus_resource), GFP_KERNEL);
67 if (!bus_res) {
68 dev_err(&bus->dev, "can't add %pR resource\n", res);
69 return;
70 }
71
72 bus_res->res = res;
73 list_add_tail(&bus_res->list, &bus->resources);
74}
75
76struct resource *pci_bus_resource_n(const struct pci_bus *bus, int n)
77{
78 struct pci_bus_resource *bus_res;
79
80 if (n < PCI_BRIDGE_RESOURCE_NUM)
81 return bus->resource[n];
82
83 n -= PCI_BRIDGE_RESOURCE_NUM;
84 list_for_each_entry(bus_res, &bus->resources, list) {
85 if (n-- == 0)
86 return bus_res->res;
87 }
88 return NULL;
89}
90EXPORT_SYMBOL_GPL(pci_bus_resource_n);
91
92void pci_bus_remove_resource(struct pci_bus *bus, struct resource *res)
93{
94 struct pci_bus_resource *bus_res, *tmp;
95 int i;
96
97 for (i = 0; i < PCI_BRIDGE_RESOURCE_NUM; i++) {
98 if (bus->resource[i] == res) {
99 bus->resource[i] = NULL;
100 return;
101 }
102 }
103
104 list_for_each_entry_safe(bus_res, tmp, &bus->resources, list) {
105 if (bus_res->res == res) {
106 list_del(&bus_res->list);
107 kfree(bus_res);
108 return;
109 }
110 }
111}
112
113void pci_bus_remove_resources(struct pci_bus *bus)
114{
115 int i;
116 struct pci_bus_resource *bus_res, *tmp;
117
118 for (i = 0; i < PCI_BRIDGE_RESOURCE_NUM; i++)
119 bus->resource[i] = NULL;
120
121 list_for_each_entry_safe(bus_res, tmp, &bus->resources, list) {
122 list_del(&bus_res->list);
123 kfree(bus_res);
124 }
125}
126
127int devm_request_pci_bus_resources(struct device *dev,
128 struct list_head *resources)
129{
130 struct resource_entry *win;
131 struct resource *parent, *res;
132 int err;
133
134 resource_list_for_each_entry(win, resources) {
135 res = win->res;
136 switch (resource_type(res)) {
137 case IORESOURCE_IO:
138 parent = &ioport_resource;
139 break;
140 case IORESOURCE_MEM:
141 parent = &iomem_resource;
142 break;
143 default:
144 continue;
145 }
146
147 err = devm_request_resource(dev, parent, res);
148 if (err)
149 return err;
150 }
151
152 return 0;
153}
154EXPORT_SYMBOL_GPL(devm_request_pci_bus_resources);
155
156static struct pci_bus_region pci_32_bit = {0, 0xffffffffULL};
157#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
158static struct pci_bus_region pci_64_bit = {0,
159 (pci_bus_addr_t) 0xffffffffffffffffULL};
160static struct pci_bus_region pci_high = {(pci_bus_addr_t) 0x100000000ULL,
161 (pci_bus_addr_t) 0xffffffffffffffffULL};
162#endif
163
164/*
165 * @res contains CPU addresses. Clip it so the corresponding bus addresses
166 * on @bus are entirely within @region. This is used to control the bus
167 * addresses of resources we allocate, e.g., we may need a resource that
168 * can be mapped by a 32-bit BAR.
169 */
170static void pci_clip_resource_to_region(struct pci_bus *bus,
171 struct resource *res,
172 struct pci_bus_region *region)
173{
174 struct pci_bus_region r;
175
176 pcibios_resource_to_bus(bus, &r, res);
177 if (r.start < region->start)
178 r.start = region->start;
179 if (r.end > region->end)
180 r.end = region->end;
181
182 if (r.end < r.start)
183 res->end = res->start - 1;
184 else
185 pcibios_bus_to_resource(bus, res, &r);
186}
187
188static int pci_bus_alloc_from_region(struct pci_bus *bus, struct resource *res,
189 resource_size_t size, resource_size_t align,
190 resource_size_t min, unsigned long type_mask,
191 resource_alignf alignf,
192 void *alignf_data,
193 struct pci_bus_region *region)
194{
195 struct resource *r, avail;
196 resource_size_t max;
197 int ret;
198
199 type_mask |= IORESOURCE_TYPE_BITS;
200
201 pci_bus_for_each_resource(bus, r) {
202 resource_size_t min_used = min;
203
204 if (!r)
205 continue;
206
207 /* type_mask must match */
208 if ((res->flags ^ r->flags) & type_mask)
209 continue;
210
211 /* We cannot allocate a non-prefetching resource
212 from a pre-fetching area */
213 if ((r->flags & IORESOURCE_PREFETCH) &&
214 !(res->flags & IORESOURCE_PREFETCH))
215 continue;
216
217 avail = *r;
218 pci_clip_resource_to_region(bus, &avail, region);
219
220 /*
221 * "min" is typically PCIBIOS_MIN_IO or PCIBIOS_MIN_MEM to
222 * protect badly documented motherboard resources, but if
223 * this is an already-configured bridge window, its start
224 * overrides "min".
225 */
226 if (avail.start)
227 min_used = avail.start;
228
229 max = avail.end;
230
231 /* Don't bother if available space isn't large enough */
232 if (size > max - min_used + 1)
233 continue;
234
235 /* Ok, try it out.. */
236 ret = allocate_resource(r, res, size, min_used, max,
237 align, alignf, alignf_data);
238 if (ret == 0)
239 return 0;
240 }
241 return -ENOMEM;
242}
243
244/**
245 * pci_bus_alloc_resource - allocate a resource from a parent bus
246 * @bus: PCI bus
247 * @res: resource to allocate
248 * @size: size of resource to allocate
249 * @align: alignment of resource to allocate
250 * @min: minimum /proc/iomem address to allocate
251 * @type_mask: IORESOURCE_* type flags
252 * @alignf: resource alignment function
253 * @alignf_data: data argument for resource alignment function
254 *
255 * Given the PCI bus a device resides on, the size, minimum address,
256 * alignment and type, try to find an acceptable resource allocation
257 * for a specific device resource.
258 */
259int pci_bus_alloc_resource(struct pci_bus *bus, struct resource *res,
260 resource_size_t size, resource_size_t align,
261 resource_size_t min, unsigned long type_mask,
262 resource_alignf alignf,
263 void *alignf_data)
264{
265#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
266 int rc;
267
268 if (res->flags & IORESOURCE_MEM_64) {
269 rc = pci_bus_alloc_from_region(bus, res, size, align, min,
270 type_mask, alignf, alignf_data,
271 &pci_high);
272 if (rc == 0)
273 return 0;
274
275 return pci_bus_alloc_from_region(bus, res, size, align, min,
276 type_mask, alignf, alignf_data,
277 &pci_64_bit);
278 }
279#endif
280
281 return pci_bus_alloc_from_region(bus, res, size, align, min,
282 type_mask, alignf, alignf_data,
283 &pci_32_bit);
284}
285EXPORT_SYMBOL(pci_bus_alloc_resource);
286
287/*
288 * The @idx resource of @dev should be a PCI-PCI bridge window. If this
289 * resource fits inside a window of an upstream bridge, do nothing. If it
290 * overlaps an upstream window but extends outside it, clip the resource so
291 * it fits completely inside.
292 */
293bool pci_bus_clip_resource(struct pci_dev *dev, int idx)
294{
295 struct pci_bus *bus = dev->bus;
296 struct resource *res = &dev->resource[idx];
297 struct resource orig_res = *res;
298 struct resource *r;
299
300 pci_bus_for_each_resource(bus, r) {
301 resource_size_t start, end;
302
303 if (!r)
304 continue;
305
306 if (resource_type(res) != resource_type(r))
307 continue;
308
309 start = max(r->start, res->start);
310 end = min(r->end, res->end);
311
312 if (start > end)
313 continue; /* no overlap */
314
315 if (res->start == start && res->end == end)
316 return false; /* no change */
317
318 res->start = start;
319 res->end = end;
320 res->flags &= ~IORESOURCE_UNSET;
321 orig_res.flags &= ~IORESOURCE_UNSET;
322 pci_info(dev, "%pR clipped to %pR\n", &orig_res, res);
323
324 return true;
325 }
326
327 return false;
328}
329
330void __weak pcibios_resource_survey_bus(struct pci_bus *bus) { }
331
332void __weak pcibios_bus_add_device(struct pci_dev *pdev) { }
333
334/*
335 * Create pwrctrl devices (if required) for the PCI devices to handle the power
336 * state.
337 */
338static void pci_pwrctrl_create_devices(struct pci_dev *dev)
339{
340 struct device_node *np = dev_of_node(&dev->dev);
341 struct device *parent = &dev->dev;
342 struct platform_device *pdev;
343
344 /*
345 * First ensure that we are starting from a PCI bridge and it has a
346 * corresponding devicetree node.
347 */
348 if (np && pci_is_bridge(dev)) {
349 /*
350 * Now look for the child PCI device nodes and create pwrctrl
351 * devices for them. The pwrctrl device drivers will manage the
352 * power state of the devices.
353 */
354 for_each_available_child_of_node_scoped(np, child) {
355 /*
356 * First check whether the pwrctrl device really
357 * needs to be created or not. This is decided
358 * based on at least one of the power supplies
359 * being defined in the devicetree node of the
360 * device.
361 */
362 if (!of_pci_supply_present(child)) {
363 pci_dbg(dev, "skipping OF node: %s\n", child->name);
364 return;
365 }
366
367 /* Now create the pwrctrl device */
368 pdev = of_platform_device_create(child, NULL, parent);
369 if (!pdev)
370 pci_err(dev, "failed to create OF node: %s\n", child->name);
371 }
372 }
373}
374
375/**
376 * pci_bus_add_device - start driver for a single device
377 * @dev: device to add
378 *
379 * This adds add sysfs entries and start device drivers
380 */
381void pci_bus_add_device(struct pci_dev *dev)
382{
383 struct device_node *dn = dev->dev.of_node;
384 struct platform_device *pdev;
385 int retval;
386
387 /*
388 * Can not put in pci_device_add yet because resources
389 * are not assigned yet for some devices.
390 */
391 pcibios_bus_add_device(dev);
392 pci_fixup_device(pci_fixup_final, dev);
393 if (pci_is_bridge(dev))
394 of_pci_make_dev_node(dev);
395 pci_create_sysfs_dev_files(dev);
396 pci_proc_attach_device(dev);
397 pci_bridge_d3_update(dev);
398
399 pci_pwrctrl_create_devices(dev);
400
401 /*
402 * If the PCI device is associated with a pwrctrl device with a
403 * power supply, create a device link between the PCI device and
404 * pwrctrl device. This ensures that pwrctrl drivers are probed
405 * before PCI client drivers.
406 */
407 pdev = of_find_device_by_node(dn);
408 if (pdev && of_pci_supply_present(dn)) {
409 if (!device_link_add(&dev->dev, &pdev->dev,
410 DL_FLAG_AUTOREMOVE_CONSUMER))
411 pci_err(dev, "failed to add device link to power control device %s\n",
412 pdev->name);
413 }
414
415 dev->match_driver = !dn || of_device_is_available(dn);
416 retval = device_attach(&dev->dev);
417 if (retval < 0 && retval != -EPROBE_DEFER)
418 pci_warn(dev, "device attach failed (%d)\n", retval);
419
420 pci_dev_assign_added(dev);
421}
422EXPORT_SYMBOL_GPL(pci_bus_add_device);
423
424/**
425 * pci_bus_add_devices - start driver for PCI devices
426 * @bus: bus to check for new devices
427 *
428 * Start driver for PCI devices and add some sysfs entries.
429 */
430void pci_bus_add_devices(const struct pci_bus *bus)
431{
432 struct pci_dev *dev;
433 struct pci_bus *child;
434
435 list_for_each_entry(dev, &bus->devices, bus_list) {
436 /* Skip already-added devices */
437 if (pci_dev_is_added(dev))
438 continue;
439 pci_bus_add_device(dev);
440 }
441
442 list_for_each_entry(dev, &bus->devices, bus_list) {
443 /* Skip if device attach failed */
444 if (!pci_dev_is_added(dev))
445 continue;
446 child = dev->subordinate;
447 if (child)
448 pci_bus_add_devices(child);
449 }
450}
451EXPORT_SYMBOL(pci_bus_add_devices);
452
453static int __pci_walk_bus(struct pci_bus *top, int (*cb)(struct pci_dev *, void *),
454 void *userdata)
455{
456 struct pci_dev *dev;
457 int ret = 0;
458
459 list_for_each_entry(dev, &top->devices, bus_list) {
460 ret = cb(dev, userdata);
461 if (ret)
462 break;
463 if (dev->subordinate) {
464 ret = __pci_walk_bus(dev->subordinate, cb, userdata);
465 if (ret)
466 break;
467 }
468 }
469 return ret;
470}
471
472/**
473 * pci_walk_bus - walk devices on/under bus, calling callback.
474 * @top: bus whose devices should be walked
475 * @cb: callback to be called for each device found
476 * @userdata: arbitrary pointer to be passed to callback
477 *
478 * Walk the given bus, including any bridged devices
479 * on buses under this bus. Call the provided callback
480 * on each device found.
481 *
482 * We check the return of @cb each time. If it returns anything
483 * other than 0, we break out.
484 */
485void pci_walk_bus(struct pci_bus *top, int (*cb)(struct pci_dev *, void *), void *userdata)
486{
487 down_read(&pci_bus_sem);
488 __pci_walk_bus(top, cb, userdata);
489 up_read(&pci_bus_sem);
490}
491EXPORT_SYMBOL_GPL(pci_walk_bus);
492
493void pci_walk_bus_locked(struct pci_bus *top, int (*cb)(struct pci_dev *, void *), void *userdata)
494{
495 lockdep_assert_held(&pci_bus_sem);
496
497 __pci_walk_bus(top, cb, userdata);
498}
499
500struct pci_bus *pci_bus_get(struct pci_bus *bus)
501{
502 if (bus)
503 get_device(&bus->dev);
504 return bus;
505}
506
507void pci_bus_put(struct pci_bus *bus)
508{
509 if (bus)
510 put_device(&bus->dev);
511}
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);