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1#include <linux/virtio.h>
2#include <linux/spinlock.h>
3#include <linux/virtio_config.h>
4
5/* Unique numbering for virtio devices. */
6static unsigned int dev_index;
7
8static ssize_t device_show(struct device *_d,
9 struct device_attribute *attr, char *buf)
10{
11 struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
12 return sprintf(buf, "0x%04x\n", dev->id.device);
13}
14static ssize_t vendor_show(struct device *_d,
15 struct device_attribute *attr, char *buf)
16{
17 struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
18 return sprintf(buf, "0x%04x\n", dev->id.vendor);
19}
20static ssize_t status_show(struct device *_d,
21 struct device_attribute *attr, char *buf)
22{
23 struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
24 return sprintf(buf, "0x%08x\n", dev->config->get_status(dev));
25}
26static ssize_t modalias_show(struct device *_d,
27 struct device_attribute *attr, char *buf)
28{
29 struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
30
31 return sprintf(buf, "virtio:d%08Xv%08X\n",
32 dev->id.device, dev->id.vendor);
33}
34static ssize_t features_show(struct device *_d,
35 struct device_attribute *attr, char *buf)
36{
37 struct virtio_device *dev = container_of(_d, struct virtio_device, dev);
38 unsigned int i;
39 ssize_t len = 0;
40
41 /* We actually represent this as a bitstring, as it could be
42 * arbitrary length in future. */
43 for (i = 0; i < ARRAY_SIZE(dev->features)*BITS_PER_LONG; i++)
44 len += sprintf(buf+len, "%c",
45 test_bit(i, dev->features) ? '1' : '0');
46 len += sprintf(buf+len, "\n");
47 return len;
48}
49static struct device_attribute virtio_dev_attrs[] = {
50 __ATTR_RO(device),
51 __ATTR_RO(vendor),
52 __ATTR_RO(status),
53 __ATTR_RO(modalias),
54 __ATTR_RO(features),
55 __ATTR_NULL
56};
57
58static inline int virtio_id_match(const struct virtio_device *dev,
59 const struct virtio_device_id *id)
60{
61 if (id->device != dev->id.device && id->device != VIRTIO_DEV_ANY_ID)
62 return 0;
63
64 return id->vendor == VIRTIO_DEV_ANY_ID || id->vendor == dev->id.vendor;
65}
66
67/* This looks through all the IDs a driver claims to support. If any of them
68 * match, we return 1 and the kernel will call virtio_dev_probe(). */
69static int virtio_dev_match(struct device *_dv, struct device_driver *_dr)
70{
71 unsigned int i;
72 struct virtio_device *dev = container_of(_dv,struct virtio_device,dev);
73 const struct virtio_device_id *ids;
74
75 ids = container_of(_dr, struct virtio_driver, driver)->id_table;
76 for (i = 0; ids[i].device; i++)
77 if (virtio_id_match(dev, &ids[i]))
78 return 1;
79 return 0;
80}
81
82static int virtio_uevent(struct device *_dv, struct kobj_uevent_env *env)
83{
84 struct virtio_device *dev = container_of(_dv,struct virtio_device,dev);
85
86 return add_uevent_var(env, "MODALIAS=virtio:d%08Xv%08X",
87 dev->id.device, dev->id.vendor);
88}
89
90static void add_status(struct virtio_device *dev, unsigned status)
91{
92 dev->config->set_status(dev, dev->config->get_status(dev) | status);
93}
94
95void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
96 unsigned int fbit)
97{
98 unsigned int i;
99 struct virtio_driver *drv = container_of(vdev->dev.driver,
100 struct virtio_driver, driver);
101
102 for (i = 0; i < drv->feature_table_size; i++)
103 if (drv->feature_table[i] == fbit)
104 return;
105 BUG();
106}
107EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature);
108
109static int virtio_dev_probe(struct device *_d)
110{
111 int err, i;
112 struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
113 struct virtio_driver *drv = container_of(dev->dev.driver,
114 struct virtio_driver, driver);
115 u32 device_features;
116
117 /* We have a driver! */
118 add_status(dev, VIRTIO_CONFIG_S_DRIVER);
119
120 /* Figure out what features the device supports. */
121 device_features = dev->config->get_features(dev);
122
123 /* Features supported by both device and driver into dev->features. */
124 memset(dev->features, 0, sizeof(dev->features));
125 for (i = 0; i < drv->feature_table_size; i++) {
126 unsigned int f = drv->feature_table[i];
127 BUG_ON(f >= 32);
128 if (device_features & (1 << f))
129 set_bit(f, dev->features);
130 }
131
132 /* Transport features always preserved to pass to finalize_features. */
133 for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
134 if (device_features & (1 << i))
135 set_bit(i, dev->features);
136
137 dev->config->finalize_features(dev);
138
139 err = drv->probe(dev);
140 if (err)
141 add_status(dev, VIRTIO_CONFIG_S_FAILED);
142 else
143 add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
144
145 return err;
146}
147
148static int virtio_dev_remove(struct device *_d)
149{
150 struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
151 struct virtio_driver *drv = container_of(dev->dev.driver,
152 struct virtio_driver, driver);
153
154 drv->remove(dev);
155
156 /* Driver should have reset device. */
157 BUG_ON(dev->config->get_status(dev));
158
159 /* Acknowledge the device's existence again. */
160 add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
161 return 0;
162}
163
164static struct bus_type virtio_bus = {
165 .name = "virtio",
166 .match = virtio_dev_match,
167 .dev_attrs = virtio_dev_attrs,
168 .uevent = virtio_uevent,
169 .probe = virtio_dev_probe,
170 .remove = virtio_dev_remove,
171};
172
173int register_virtio_driver(struct virtio_driver *driver)
174{
175 /* Catch this early. */
176 BUG_ON(driver->feature_table_size && !driver->feature_table);
177 driver->driver.bus = &virtio_bus;
178 return driver_register(&driver->driver);
179}
180EXPORT_SYMBOL_GPL(register_virtio_driver);
181
182void unregister_virtio_driver(struct virtio_driver *driver)
183{
184 driver_unregister(&driver->driver);
185}
186EXPORT_SYMBOL_GPL(unregister_virtio_driver);
187
188int register_virtio_device(struct virtio_device *dev)
189{
190 int err;
191
192 dev->dev.bus = &virtio_bus;
193
194 /* Assign a unique device index and hence name. */
195 dev->index = dev_index++;
196 dev_set_name(&dev->dev, "virtio%u", dev->index);
197
198 /* We always start by resetting the device, in case a previous
199 * driver messed it up. This also tests that code path a little. */
200 dev->config->reset(dev);
201
202 /* Acknowledge that we've seen the device. */
203 add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
204
205 INIT_LIST_HEAD(&dev->vqs);
206
207 /* device_register() causes the bus infrastructure to look for a
208 * matching driver. */
209 err = device_register(&dev->dev);
210 if (err)
211 add_status(dev, VIRTIO_CONFIG_S_FAILED);
212 return err;
213}
214EXPORT_SYMBOL_GPL(register_virtio_device);
215
216void unregister_virtio_device(struct virtio_device *dev)
217{
218 device_unregister(&dev->dev);
219}
220EXPORT_SYMBOL_GPL(unregister_virtio_device);
221
222static int virtio_init(void)
223{
224 if (bus_register(&virtio_bus) != 0)
225 panic("virtio bus registration failed");
226 return 0;
227}
228
229static void __exit virtio_exit(void)
230{
231 bus_unregister(&virtio_bus);
232}
233core_initcall(virtio_init);
234module_exit(virtio_exit);
235
236MODULE_LICENSE("GPL");
1// SPDX-License-Identifier: GPL-2.0-only
2#include <linux/virtio.h>
3#include <linux/spinlock.h>
4#include <linux/virtio_config.h>
5#include <linux/virtio_anchor.h>
6#include <linux/module.h>
7#include <linux/idr.h>
8#include <linux/of.h>
9#include <uapi/linux/virtio_ids.h>
10
11/* Unique numbering for virtio devices. */
12static DEFINE_IDA(virtio_index_ida);
13
14static ssize_t device_show(struct device *_d,
15 struct device_attribute *attr, char *buf)
16{
17 struct virtio_device *dev = dev_to_virtio(_d);
18 return sysfs_emit(buf, "0x%04x\n", dev->id.device);
19}
20static DEVICE_ATTR_RO(device);
21
22static ssize_t vendor_show(struct device *_d,
23 struct device_attribute *attr, char *buf)
24{
25 struct virtio_device *dev = dev_to_virtio(_d);
26 return sysfs_emit(buf, "0x%04x\n", dev->id.vendor);
27}
28static DEVICE_ATTR_RO(vendor);
29
30static ssize_t status_show(struct device *_d,
31 struct device_attribute *attr, char *buf)
32{
33 struct virtio_device *dev = dev_to_virtio(_d);
34 return sysfs_emit(buf, "0x%08x\n", dev->config->get_status(dev));
35}
36static DEVICE_ATTR_RO(status);
37
38static ssize_t modalias_show(struct device *_d,
39 struct device_attribute *attr, char *buf)
40{
41 struct virtio_device *dev = dev_to_virtio(_d);
42 return sysfs_emit(buf, "virtio:d%08Xv%08X\n",
43 dev->id.device, dev->id.vendor);
44}
45static DEVICE_ATTR_RO(modalias);
46
47static ssize_t features_show(struct device *_d,
48 struct device_attribute *attr, char *buf)
49{
50 struct virtio_device *dev = dev_to_virtio(_d);
51 unsigned int i;
52 ssize_t len = 0;
53
54 /* We actually represent this as a bitstring, as it could be
55 * arbitrary length in future. */
56 for (i = 0; i < sizeof(dev->features)*8; i++)
57 len += sysfs_emit_at(buf, len, "%c",
58 __virtio_test_bit(dev, i) ? '1' : '0');
59 len += sysfs_emit_at(buf, len, "\n");
60 return len;
61}
62static DEVICE_ATTR_RO(features);
63
64static struct attribute *virtio_dev_attrs[] = {
65 &dev_attr_device.attr,
66 &dev_attr_vendor.attr,
67 &dev_attr_status.attr,
68 &dev_attr_modalias.attr,
69 &dev_attr_features.attr,
70 NULL,
71};
72ATTRIBUTE_GROUPS(virtio_dev);
73
74static inline int virtio_id_match(const struct virtio_device *dev,
75 const struct virtio_device_id *id)
76{
77 if (id->device != dev->id.device && id->device != VIRTIO_DEV_ANY_ID)
78 return 0;
79
80 return id->vendor == VIRTIO_DEV_ANY_ID || id->vendor == dev->id.vendor;
81}
82
83/* This looks through all the IDs a driver claims to support. If any of them
84 * match, we return 1 and the kernel will call virtio_dev_probe(). */
85static int virtio_dev_match(struct device *_dv, struct device_driver *_dr)
86{
87 unsigned int i;
88 struct virtio_device *dev = dev_to_virtio(_dv);
89 const struct virtio_device_id *ids;
90
91 ids = drv_to_virtio(_dr)->id_table;
92 for (i = 0; ids[i].device; i++)
93 if (virtio_id_match(dev, &ids[i]))
94 return 1;
95 return 0;
96}
97
98static int virtio_uevent(const struct device *_dv, struct kobj_uevent_env *env)
99{
100 const struct virtio_device *dev = dev_to_virtio(_dv);
101
102 return add_uevent_var(env, "MODALIAS=virtio:d%08Xv%08X",
103 dev->id.device, dev->id.vendor);
104}
105
106void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
107 unsigned int fbit)
108{
109 unsigned int i;
110 struct virtio_driver *drv = drv_to_virtio(vdev->dev.driver);
111
112 for (i = 0; i < drv->feature_table_size; i++)
113 if (drv->feature_table[i] == fbit)
114 return;
115
116 if (drv->feature_table_legacy) {
117 for (i = 0; i < drv->feature_table_size_legacy; i++)
118 if (drv->feature_table_legacy[i] == fbit)
119 return;
120 }
121
122 BUG();
123}
124EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature);
125
126static void __virtio_config_changed(struct virtio_device *dev)
127{
128 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
129
130 if (!dev->config_enabled)
131 dev->config_change_pending = true;
132 else if (drv && drv->config_changed)
133 drv->config_changed(dev);
134}
135
136void virtio_config_changed(struct virtio_device *dev)
137{
138 unsigned long flags;
139
140 spin_lock_irqsave(&dev->config_lock, flags);
141 __virtio_config_changed(dev);
142 spin_unlock_irqrestore(&dev->config_lock, flags);
143}
144EXPORT_SYMBOL_GPL(virtio_config_changed);
145
146static void virtio_config_disable(struct virtio_device *dev)
147{
148 spin_lock_irq(&dev->config_lock);
149 dev->config_enabled = false;
150 spin_unlock_irq(&dev->config_lock);
151}
152
153static void virtio_config_enable(struct virtio_device *dev)
154{
155 spin_lock_irq(&dev->config_lock);
156 dev->config_enabled = true;
157 if (dev->config_change_pending)
158 __virtio_config_changed(dev);
159 dev->config_change_pending = false;
160 spin_unlock_irq(&dev->config_lock);
161}
162
163void virtio_add_status(struct virtio_device *dev, unsigned int status)
164{
165 might_sleep();
166 dev->config->set_status(dev, dev->config->get_status(dev) | status);
167}
168EXPORT_SYMBOL_GPL(virtio_add_status);
169
170/* Do some validation, then set FEATURES_OK */
171static int virtio_features_ok(struct virtio_device *dev)
172{
173 unsigned int status;
174
175 might_sleep();
176
177 if (virtio_check_mem_acc_cb(dev)) {
178 if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) {
179 dev_warn(&dev->dev,
180 "device must provide VIRTIO_F_VERSION_1\n");
181 return -ENODEV;
182 }
183
184 if (!virtio_has_feature(dev, VIRTIO_F_ACCESS_PLATFORM)) {
185 dev_warn(&dev->dev,
186 "device must provide VIRTIO_F_ACCESS_PLATFORM\n");
187 return -ENODEV;
188 }
189 }
190
191 if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1))
192 return 0;
193
194 virtio_add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK);
195 status = dev->config->get_status(dev);
196 if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) {
197 dev_err(&dev->dev, "virtio: device refuses features: %x\n",
198 status);
199 return -ENODEV;
200 }
201 return 0;
202}
203
204/**
205 * virtio_reset_device - quiesce device for removal
206 * @dev: the device to reset
207 *
208 * Prevents device from sending interrupts and accessing memory.
209 *
210 * Generally used for cleanup during driver / device removal.
211 *
212 * Once this has been invoked, caller must ensure that
213 * virtqueue_notify / virtqueue_kick are not in progress.
214 *
215 * Note: this guarantees that vq callbacks are not in progress, however caller
216 * is responsible for preventing access from other contexts, such as a system
217 * call/workqueue/bh. Invoking virtio_break_device then flushing any such
218 * contexts is one way to handle that.
219 * */
220void virtio_reset_device(struct virtio_device *dev)
221{
222#ifdef CONFIG_VIRTIO_HARDEN_NOTIFICATION
223 /*
224 * The below virtio_synchronize_cbs() guarantees that any
225 * interrupt for this line arriving after
226 * virtio_synchronize_vqs() has completed is guaranteed to see
227 * vq->broken as true.
228 */
229 virtio_break_device(dev);
230 virtio_synchronize_cbs(dev);
231#endif
232
233 dev->config->reset(dev);
234}
235EXPORT_SYMBOL_GPL(virtio_reset_device);
236
237static int virtio_dev_probe(struct device *_d)
238{
239 int err, i;
240 struct virtio_device *dev = dev_to_virtio(_d);
241 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
242 u64 device_features;
243 u64 driver_features;
244 u64 driver_features_legacy;
245
246 /* We have a driver! */
247 virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER);
248
249 /* Figure out what features the device supports. */
250 device_features = dev->config->get_features(dev);
251
252 /* Figure out what features the driver supports. */
253 driver_features = 0;
254 for (i = 0; i < drv->feature_table_size; i++) {
255 unsigned int f = drv->feature_table[i];
256 BUG_ON(f >= 64);
257 driver_features |= (1ULL << f);
258 }
259
260 /* Some drivers have a separate feature table for virtio v1.0 */
261 if (drv->feature_table_legacy) {
262 driver_features_legacy = 0;
263 for (i = 0; i < drv->feature_table_size_legacy; i++) {
264 unsigned int f = drv->feature_table_legacy[i];
265 BUG_ON(f >= 64);
266 driver_features_legacy |= (1ULL << f);
267 }
268 } else {
269 driver_features_legacy = driver_features;
270 }
271
272 if (device_features & (1ULL << VIRTIO_F_VERSION_1))
273 dev->features = driver_features & device_features;
274 else
275 dev->features = driver_features_legacy & device_features;
276
277 /* Transport features always preserved to pass to finalize_features. */
278 for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
279 if (device_features & (1ULL << i))
280 __virtio_set_bit(dev, i);
281
282 err = dev->config->finalize_features(dev);
283 if (err)
284 goto err;
285
286 if (drv->validate) {
287 u64 features = dev->features;
288
289 err = drv->validate(dev);
290 if (err)
291 goto err;
292
293 /* Did validation change any features? Then write them again. */
294 if (features != dev->features) {
295 err = dev->config->finalize_features(dev);
296 if (err)
297 goto err;
298 }
299 }
300
301 err = virtio_features_ok(dev);
302 if (err)
303 goto err;
304
305 if (dev->config->create_avq) {
306 err = dev->config->create_avq(dev);
307 if (err)
308 goto err;
309 }
310
311 err = drv->probe(dev);
312 if (err)
313 goto err_probe;
314
315 /* If probe didn't do it, mark device DRIVER_OK ourselves. */
316 if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK))
317 virtio_device_ready(dev);
318
319 if (drv->scan)
320 drv->scan(dev);
321
322 virtio_config_enable(dev);
323
324 return 0;
325
326err_probe:
327 if (dev->config->destroy_avq)
328 dev->config->destroy_avq(dev);
329err:
330 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
331 return err;
332
333}
334
335static void virtio_dev_remove(struct device *_d)
336{
337 struct virtio_device *dev = dev_to_virtio(_d);
338 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
339
340 virtio_config_disable(dev);
341
342 drv->remove(dev);
343
344 if (dev->config->destroy_avq)
345 dev->config->destroy_avq(dev);
346
347 /* Driver should have reset device. */
348 WARN_ON_ONCE(dev->config->get_status(dev));
349
350 /* Acknowledge the device's existence again. */
351 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
352
353 of_node_put(dev->dev.of_node);
354}
355
356static struct bus_type virtio_bus = {
357 .name = "virtio",
358 .match = virtio_dev_match,
359 .dev_groups = virtio_dev_groups,
360 .uevent = virtio_uevent,
361 .probe = virtio_dev_probe,
362 .remove = virtio_dev_remove,
363};
364
365int register_virtio_driver(struct virtio_driver *driver)
366{
367 /* Catch this early. */
368 BUG_ON(driver->feature_table_size && !driver->feature_table);
369 driver->driver.bus = &virtio_bus;
370 return driver_register(&driver->driver);
371}
372EXPORT_SYMBOL_GPL(register_virtio_driver);
373
374void unregister_virtio_driver(struct virtio_driver *driver)
375{
376 driver_unregister(&driver->driver);
377}
378EXPORT_SYMBOL_GPL(unregister_virtio_driver);
379
380static int virtio_device_of_init(struct virtio_device *dev)
381{
382 struct device_node *np, *pnode = dev_of_node(dev->dev.parent);
383 char compat[] = "virtio,deviceXXXXXXXX";
384 int ret, count;
385
386 if (!pnode)
387 return 0;
388
389 count = of_get_available_child_count(pnode);
390 if (!count)
391 return 0;
392
393 /* There can be only 1 child node */
394 if (WARN_ON(count > 1))
395 return -EINVAL;
396
397 np = of_get_next_available_child(pnode, NULL);
398 if (WARN_ON(!np))
399 return -ENODEV;
400
401 ret = snprintf(compat, sizeof(compat), "virtio,device%x", dev->id.device);
402 BUG_ON(ret >= sizeof(compat));
403
404 /*
405 * On powerpc/pseries virtio devices are PCI devices so PCI
406 * vendor/device ids play the role of the "compatible" property.
407 * Simply don't init of_node in this case.
408 */
409 if (!of_device_is_compatible(np, compat)) {
410 ret = 0;
411 goto out;
412 }
413
414 dev->dev.of_node = np;
415 return 0;
416
417out:
418 of_node_put(np);
419 return ret;
420}
421
422/**
423 * register_virtio_device - register virtio device
424 * @dev : virtio device to be registered
425 *
426 * On error, the caller must call put_device on &@dev->dev (and not kfree),
427 * as another code path may have obtained a reference to @dev.
428 *
429 * Returns: 0 on suceess, -error on failure
430 */
431int register_virtio_device(struct virtio_device *dev)
432{
433 int err;
434
435 dev->dev.bus = &virtio_bus;
436 device_initialize(&dev->dev);
437
438 /* Assign a unique device index and hence name. */
439 err = ida_alloc(&virtio_index_ida, GFP_KERNEL);
440 if (err < 0)
441 goto out;
442
443 dev->index = err;
444 err = dev_set_name(&dev->dev, "virtio%u", dev->index);
445 if (err)
446 goto out_ida_remove;
447
448 err = virtio_device_of_init(dev);
449 if (err)
450 goto out_ida_remove;
451
452 spin_lock_init(&dev->config_lock);
453 dev->config_enabled = false;
454 dev->config_change_pending = false;
455
456 INIT_LIST_HEAD(&dev->vqs);
457 spin_lock_init(&dev->vqs_list_lock);
458
459 /* We always start by resetting the device, in case a previous
460 * driver messed it up. This also tests that code path a little. */
461 virtio_reset_device(dev);
462
463 /* Acknowledge that we've seen the device. */
464 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
465
466 /*
467 * device_add() causes the bus infrastructure to look for a matching
468 * driver.
469 */
470 err = device_add(&dev->dev);
471 if (err)
472 goto out_of_node_put;
473
474 return 0;
475
476out_of_node_put:
477 of_node_put(dev->dev.of_node);
478out_ida_remove:
479 ida_free(&virtio_index_ida, dev->index);
480out:
481 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
482 return err;
483}
484EXPORT_SYMBOL_GPL(register_virtio_device);
485
486bool is_virtio_device(struct device *dev)
487{
488 return dev->bus == &virtio_bus;
489}
490EXPORT_SYMBOL_GPL(is_virtio_device);
491
492void unregister_virtio_device(struct virtio_device *dev)
493{
494 int index = dev->index; /* save for after device release */
495
496 device_unregister(&dev->dev);
497 ida_free(&virtio_index_ida, index);
498}
499EXPORT_SYMBOL_GPL(unregister_virtio_device);
500
501#ifdef CONFIG_PM_SLEEP
502int virtio_device_freeze(struct virtio_device *dev)
503{
504 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
505 int ret;
506
507 virtio_config_disable(dev);
508
509 dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED;
510
511 if (drv && drv->freeze) {
512 ret = drv->freeze(dev);
513 if (ret)
514 return ret;
515 }
516
517 if (dev->config->destroy_avq)
518 dev->config->destroy_avq(dev);
519
520 return 0;
521}
522EXPORT_SYMBOL_GPL(virtio_device_freeze);
523
524int virtio_device_restore(struct virtio_device *dev)
525{
526 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
527 int ret;
528
529 /* We always start by resetting the device, in case a previous
530 * driver messed it up. */
531 virtio_reset_device(dev);
532
533 /* Acknowledge that we've seen the device. */
534 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
535
536 /* Maybe driver failed before freeze.
537 * Restore the failed status, for debugging. */
538 if (dev->failed)
539 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
540
541 if (!drv)
542 return 0;
543
544 /* We have a driver! */
545 virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER);
546
547 ret = dev->config->finalize_features(dev);
548 if (ret)
549 goto err;
550
551 ret = virtio_features_ok(dev);
552 if (ret)
553 goto err;
554
555 if (dev->config->create_avq) {
556 ret = dev->config->create_avq(dev);
557 if (ret)
558 goto err;
559 }
560
561 if (drv->restore) {
562 ret = drv->restore(dev);
563 if (ret)
564 goto err_restore;
565 }
566
567 /* If restore didn't do it, mark device DRIVER_OK ourselves. */
568 if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK))
569 virtio_device_ready(dev);
570
571 virtio_config_enable(dev);
572
573 return 0;
574
575err_restore:
576 if (dev->config->destroy_avq)
577 dev->config->destroy_avq(dev);
578err:
579 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
580 return ret;
581}
582EXPORT_SYMBOL_GPL(virtio_device_restore);
583#endif
584
585static int virtio_init(void)
586{
587 if (bus_register(&virtio_bus) != 0)
588 panic("virtio bus registration failed");
589 return 0;
590}
591
592static void __exit virtio_exit(void)
593{
594 bus_unregister(&virtio_bus);
595 ida_destroy(&virtio_index_ida);
596}
597core_initcall(virtio_init);
598module_exit(virtio_exit);
599
600MODULE_LICENSE("GPL");