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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/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);
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/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 pr_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_resource(struct pci_bus *bus, struct resource *res)
81{
82 struct pci_bus_resource *bus_res, *tmp;
83 int i;
84
85 for (i = 0; i < PCI_BRIDGE_RESOURCE_NUM; i++) {
86 if (bus->resource[i] == res) {
87 bus->resource[i] = NULL;
88 return;
89 }
90 }
91
92 list_for_each_entry_safe(bus_res, tmp, &bus->resources, list) {
93 if (bus_res->res == res) {
94 list_del(&bus_res->list);
95 kfree(bus_res);
96 return;
97 }
98 }
99}
100
101void pci_bus_remove_resources(struct pci_bus *bus)
102{
103 int i;
104 struct pci_bus_resource *bus_res, *tmp;
105
106 for (i = 0; i < PCI_BRIDGE_RESOURCE_NUM; i++)
107 bus->resource[i] = NULL;
108
109 list_for_each_entry_safe(bus_res, tmp, &bus->resources, list) {
110 list_del(&bus_res->list);
111 kfree(bus_res);
112 }
113}
114
115int devm_request_pci_bus_resources(struct device *dev,
116 struct list_head *resources)
117{
118 struct resource_entry *win;
119 struct resource *parent, *res;
120 int err;
121
122 resource_list_for_each_entry(win, resources) {
123 res = win->res;
124 switch (resource_type(res)) {
125 case IORESOURCE_IO:
126 parent = &ioport_resource;
127 break;
128 case IORESOURCE_MEM:
129 parent = &iomem_resource;
130 break;
131 default:
132 continue;
133 }
134
135 err = devm_request_resource(dev, parent, res);
136 if (err)
137 return err;
138 }
139
140 return 0;
141}
142EXPORT_SYMBOL_GPL(devm_request_pci_bus_resources);
143
144static struct pci_bus_region pci_32_bit = {0, 0xffffffffULL};
145#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
146static struct pci_bus_region pci_64_bit = {0,
147 (pci_bus_addr_t) 0xffffffffffffffffULL};
148static struct pci_bus_region pci_high = {(pci_bus_addr_t) 0x100000000ULL,
149 (pci_bus_addr_t) 0xffffffffffffffffULL};
150#endif
151
152/*
153 * @res contains CPU addresses. Clip it so the corresponding bus addresses
154 * on @bus are entirely within @region. This is used to control the bus
155 * addresses of resources we allocate, e.g., we may need a resource that
156 * can be mapped by a 32-bit BAR.
157 */
158static void pci_clip_resource_to_region(struct pci_bus *bus,
159 struct resource *res,
160 struct pci_bus_region *region)
161{
162 struct pci_bus_region r;
163
164 pcibios_resource_to_bus(bus, &r, res);
165 if (r.start < region->start)
166 r.start = region->start;
167 if (r.end > region->end)
168 r.end = region->end;
169
170 if (r.end < r.start)
171 res->end = res->start - 1;
172 else
173 pcibios_bus_to_resource(bus, res, &r);
174}
175
176static int pci_bus_alloc_from_region(struct pci_bus *bus, struct resource *res,
177 resource_size_t size, resource_size_t align,
178 resource_size_t min, unsigned long type_mask,
179 resource_size_t (*alignf)(void *,
180 const struct resource *,
181 resource_size_t,
182 resource_size_t),
183 void *alignf_data,
184 struct pci_bus_region *region)
185{
186 struct resource *r, avail;
187 resource_size_t max;
188 int ret;
189
190 type_mask |= IORESOURCE_TYPE_BITS;
191
192 pci_bus_for_each_resource(bus, r) {
193 resource_size_t min_used = min;
194
195 if (!r)
196 continue;
197
198 /* type_mask must match */
199 if ((res->flags ^ r->flags) & type_mask)
200 continue;
201
202 /* We cannot allocate a non-prefetching resource
203 from a pre-fetching area */
204 if ((r->flags & IORESOURCE_PREFETCH) &&
205 !(res->flags & IORESOURCE_PREFETCH))
206 continue;
207
208 avail = *r;
209 pci_clip_resource_to_region(bus, &avail, region);
210
211 /*
212 * "min" is typically PCIBIOS_MIN_IO or PCIBIOS_MIN_MEM to
213 * protect badly documented motherboard resources, but if
214 * this is an already-configured bridge window, its start
215 * overrides "min".
216 */
217 if (avail.start)
218 min_used = avail.start;
219
220 max = avail.end;
221
222 /* Don't bother if available space isn't large enough */
223 if (size > max - min_used + 1)
224 continue;
225
226 /* Ok, try it out.. */
227 ret = allocate_resource(r, res, size, min_used, max,
228 align, alignf, alignf_data);
229 if (ret == 0)
230 return 0;
231 }
232 return -ENOMEM;
233}
234
235/**
236 * pci_bus_alloc_resource - allocate a resource from a parent bus
237 * @bus: PCI bus
238 * @res: resource to allocate
239 * @size: size of resource to allocate
240 * @align: alignment of resource to allocate
241 * @min: minimum /proc/iomem address to allocate
242 * @type_mask: IORESOURCE_* type flags
243 * @alignf: resource alignment function
244 * @alignf_data: data argument for resource alignment function
245 *
246 * Given the PCI bus a device resides on, the size, minimum address,
247 * alignment and type, try to find an acceptable resource allocation
248 * for a specific device resource.
249 */
250int pci_bus_alloc_resource(struct pci_bus *bus, struct resource *res,
251 resource_size_t size, resource_size_t align,
252 resource_size_t min, unsigned long type_mask,
253 resource_size_t (*alignf)(void *,
254 const struct resource *,
255 resource_size_t,
256 resource_size_t),
257 void *alignf_data)
258{
259#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
260 int rc;
261
262 if (res->flags & IORESOURCE_MEM_64) {
263 rc = pci_bus_alloc_from_region(bus, res, size, align, min,
264 type_mask, alignf, alignf_data,
265 &pci_high);
266 if (rc == 0)
267 return 0;
268
269 return pci_bus_alloc_from_region(bus, res, size, align, min,
270 type_mask, alignf, alignf_data,
271 &pci_64_bit);
272 }
273#endif
274
275 return pci_bus_alloc_from_region(bus, res, size, align, min,
276 type_mask, alignf, alignf_data,
277 &pci_32_bit);
278}
279EXPORT_SYMBOL(pci_bus_alloc_resource);
280
281/*
282 * The @idx resource of @dev should be a PCI-PCI bridge window. If this
283 * resource fits inside a window of an upstream bridge, do nothing. If it
284 * overlaps an upstream window but extends outside it, clip the resource so
285 * it fits completely inside.
286 */
287bool pci_bus_clip_resource(struct pci_dev *dev, int idx)
288{
289 struct pci_bus *bus = dev->bus;
290 struct resource *res = &dev->resource[idx];
291 struct resource orig_res = *res;
292 struct resource *r;
293
294 pci_bus_for_each_resource(bus, r) {
295 resource_size_t start, end;
296
297 if (!r)
298 continue;
299
300 if (resource_type(res) != resource_type(r))
301 continue;
302
303 start = max(r->start, res->start);
304 end = min(r->end, res->end);
305
306 if (start > end)
307 continue; /* no overlap */
308
309 if (res->start == start && res->end == end)
310 return false; /* no change */
311
312 res->start = start;
313 res->end = end;
314 res->flags &= ~IORESOURCE_UNSET;
315 orig_res.flags &= ~IORESOURCE_UNSET;
316 pci_info(dev, "%pR clipped to %pR\n", &orig_res, res);
317
318 return true;
319 }
320
321 return false;
322}
323
324void __weak pcibios_resource_survey_bus(struct pci_bus *bus) { }
325
326void __weak pcibios_bus_add_device(struct pci_dev *pdev) { }
327
328/**
329 * pci_bus_add_device - start driver for a single device
330 * @dev: device to add
331 *
332 * This adds add sysfs entries and start device drivers
333 */
334void pci_bus_add_device(struct pci_dev *dev)
335{
336 struct device_node *dn = dev->dev.of_node;
337 int retval;
338
339 /*
340 * Can not put in pci_device_add yet because resources
341 * are not assigned yet for some devices.
342 */
343 pcibios_bus_add_device(dev);
344 pci_fixup_device(pci_fixup_final, dev);
345 if (pci_is_bridge(dev))
346 of_pci_make_dev_node(dev);
347 pci_create_sysfs_dev_files(dev);
348 pci_proc_attach_device(dev);
349 pci_bridge_d3_update(dev);
350
351 dev->match_driver = !dn || of_device_is_available(dn);
352 retval = device_attach(&dev->dev);
353 if (retval < 0 && retval != -EPROBE_DEFER)
354 pci_warn(dev, "device attach failed (%d)\n", retval);
355
356 pci_dev_assign_added(dev, true);
357}
358EXPORT_SYMBOL_GPL(pci_bus_add_device);
359
360/**
361 * pci_bus_add_devices - start driver for PCI devices
362 * @bus: bus to check for new devices
363 *
364 * Start driver for PCI devices and add some sysfs entries.
365 */
366void pci_bus_add_devices(const struct pci_bus *bus)
367{
368 struct pci_dev *dev;
369 struct pci_bus *child;
370
371 list_for_each_entry(dev, &bus->devices, bus_list) {
372 /* Skip already-added devices */
373 if (pci_dev_is_added(dev))
374 continue;
375 pci_bus_add_device(dev);
376 }
377
378 list_for_each_entry(dev, &bus->devices, bus_list) {
379 /* Skip if device attach failed */
380 if (!pci_dev_is_added(dev))
381 continue;
382 child = dev->subordinate;
383 if (child)
384 pci_bus_add_devices(child);
385 }
386}
387EXPORT_SYMBOL(pci_bus_add_devices);
388
389static void __pci_walk_bus(struct pci_bus *top, int (*cb)(struct pci_dev *, void *),
390 void *userdata, bool locked)
391{
392 struct pci_dev *dev;
393 struct pci_bus *bus;
394 struct list_head *next;
395 int retval;
396
397 bus = top;
398 if (!locked)
399 down_read(&pci_bus_sem);
400 next = top->devices.next;
401 for (;;) {
402 if (next == &bus->devices) {
403 /* end of this bus, go up or finish */
404 if (bus == top)
405 break;
406 next = bus->self->bus_list.next;
407 bus = bus->self->bus;
408 continue;
409 }
410 dev = list_entry(next, struct pci_dev, bus_list);
411 if (dev->subordinate) {
412 /* this is a pci-pci bridge, do its devices next */
413 next = dev->subordinate->devices.next;
414 bus = dev->subordinate;
415 } else
416 next = dev->bus_list.next;
417
418 retval = cb(dev, userdata);
419 if (retval)
420 break;
421 }
422 if (!locked)
423 up_read(&pci_bus_sem);
424}
425
426/**
427 * pci_walk_bus - walk devices on/under bus, calling callback.
428 * @top: bus whose devices should be walked
429 * @cb: callback to be called for each device found
430 * @userdata: arbitrary pointer to be passed to callback
431 *
432 * Walk the given bus, including any bridged devices
433 * on buses under this bus. Call the provided callback
434 * on each device found.
435 *
436 * We check the return of @cb each time. If it returns anything
437 * other than 0, we break out.
438 */
439void pci_walk_bus(struct pci_bus *top, int (*cb)(struct pci_dev *, void *), void *userdata)
440{
441 __pci_walk_bus(top, cb, userdata, false);
442}
443EXPORT_SYMBOL_GPL(pci_walk_bus);
444
445void pci_walk_bus_locked(struct pci_bus *top, int (*cb)(struct pci_dev *, void *), void *userdata)
446{
447 lockdep_assert_held(&pci_bus_sem);
448
449 __pci_walk_bus(top, cb, userdata, true);
450}
451EXPORT_SYMBOL_GPL(pci_walk_bus_locked);
452
453struct pci_bus *pci_bus_get(struct pci_bus *bus)
454{
455 if (bus)
456 get_device(&bus->dev);
457 return bus;
458}
459
460void pci_bus_put(struct pci_bus *bus)
461{
462 if (bus)
463 put_device(&bus->dev);
464}