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1#include <linux/virtio.h>
2#include <linux/spinlock.h>
3#include <linux/virtio_config.h>
4#include <linux/module.h>
5#include <linux/idr.h>
6#include <uapi/linux/virtio_ids.h>
7
8/* Unique numbering for virtio devices. */
9static DEFINE_IDA(virtio_index_ida);
10
11static ssize_t device_show(struct device *_d,
12 struct device_attribute *attr, char *buf)
13{
14 struct virtio_device *dev = dev_to_virtio(_d);
15 return sprintf(buf, "0x%04x\n", dev->id.device);
16}
17static DEVICE_ATTR_RO(device);
18
19static ssize_t vendor_show(struct device *_d,
20 struct device_attribute *attr, char *buf)
21{
22 struct virtio_device *dev = dev_to_virtio(_d);
23 return sprintf(buf, "0x%04x\n", dev->id.vendor);
24}
25static DEVICE_ATTR_RO(vendor);
26
27static ssize_t status_show(struct device *_d,
28 struct device_attribute *attr, char *buf)
29{
30 struct virtio_device *dev = dev_to_virtio(_d);
31 return sprintf(buf, "0x%08x\n", dev->config->get_status(dev));
32}
33static DEVICE_ATTR_RO(status);
34
35static ssize_t modalias_show(struct device *_d,
36 struct device_attribute *attr, char *buf)
37{
38 struct virtio_device *dev = dev_to_virtio(_d);
39 return sprintf(buf, "virtio:d%08Xv%08X\n",
40 dev->id.device, dev->id.vendor);
41}
42static DEVICE_ATTR_RO(modalias);
43
44static ssize_t features_show(struct device *_d,
45 struct device_attribute *attr, char *buf)
46{
47 struct virtio_device *dev = dev_to_virtio(_d);
48 unsigned int i;
49 ssize_t len = 0;
50
51 /* We actually represent this as a bitstring, as it could be
52 * arbitrary length in future. */
53 for (i = 0; i < sizeof(dev->features)*8; i++)
54 len += sprintf(buf+len, "%c",
55 __virtio_test_bit(dev, i) ? '1' : '0');
56 len += sprintf(buf+len, "\n");
57 return len;
58}
59static DEVICE_ATTR_RO(features);
60
61static struct attribute *virtio_dev_attrs[] = {
62 &dev_attr_device.attr,
63 &dev_attr_vendor.attr,
64 &dev_attr_status.attr,
65 &dev_attr_modalias.attr,
66 &dev_attr_features.attr,
67 NULL,
68};
69ATTRIBUTE_GROUPS(virtio_dev);
70
71static inline int virtio_id_match(const struct virtio_device *dev,
72 const struct virtio_device_id *id)
73{
74 if (id->device != dev->id.device && id->device != VIRTIO_DEV_ANY_ID)
75 return 0;
76
77 return id->vendor == VIRTIO_DEV_ANY_ID || id->vendor == dev->id.vendor;
78}
79
80/* This looks through all the IDs a driver claims to support. If any of them
81 * match, we return 1 and the kernel will call virtio_dev_probe(). */
82static int virtio_dev_match(struct device *_dv, struct device_driver *_dr)
83{
84 unsigned int i;
85 struct virtio_device *dev = dev_to_virtio(_dv);
86 const struct virtio_device_id *ids;
87
88 ids = drv_to_virtio(_dr)->id_table;
89 for (i = 0; ids[i].device; i++)
90 if (virtio_id_match(dev, &ids[i]))
91 return 1;
92 return 0;
93}
94
95static int virtio_uevent(struct device *_dv, struct kobj_uevent_env *env)
96{
97 struct virtio_device *dev = dev_to_virtio(_dv);
98
99 return add_uevent_var(env, "MODALIAS=virtio:d%08Xv%08X",
100 dev->id.device, dev->id.vendor);
101}
102
103static void add_status(struct virtio_device *dev, unsigned status)
104{
105 dev->config->set_status(dev, dev->config->get_status(dev) | status);
106}
107
108void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
109 unsigned int fbit)
110{
111 unsigned int i;
112 struct virtio_driver *drv = drv_to_virtio(vdev->dev.driver);
113
114 for (i = 0; i < drv->feature_table_size; i++)
115 if (drv->feature_table[i] == fbit)
116 return;
117
118 if (drv->feature_table_legacy) {
119 for (i = 0; i < drv->feature_table_size_legacy; i++)
120 if (drv->feature_table_legacy[i] == fbit)
121 return;
122 }
123
124 BUG();
125}
126EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature);
127
128static void __virtio_config_changed(struct virtio_device *dev)
129{
130 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
131
132 if (!dev->config_enabled)
133 dev->config_change_pending = true;
134 else if (drv && drv->config_changed)
135 drv->config_changed(dev);
136}
137
138void virtio_config_changed(struct virtio_device *dev)
139{
140 unsigned long flags;
141
142 spin_lock_irqsave(&dev->config_lock, flags);
143 __virtio_config_changed(dev);
144 spin_unlock_irqrestore(&dev->config_lock, flags);
145}
146EXPORT_SYMBOL_GPL(virtio_config_changed);
147
148static void virtio_config_disable(struct virtio_device *dev)
149{
150 spin_lock_irq(&dev->config_lock);
151 dev->config_enabled = false;
152 spin_unlock_irq(&dev->config_lock);
153}
154
155static void virtio_config_enable(struct virtio_device *dev)
156{
157 spin_lock_irq(&dev->config_lock);
158 dev->config_enabled = true;
159 if (dev->config_change_pending)
160 __virtio_config_changed(dev);
161 dev->config_change_pending = false;
162 spin_unlock_irq(&dev->config_lock);
163}
164
165static int virtio_finalize_features(struct virtio_device *dev)
166{
167 int ret = dev->config->finalize_features(dev);
168 unsigned status;
169
170 if (ret)
171 return ret;
172
173 if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1))
174 return 0;
175
176 add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK);
177 status = dev->config->get_status(dev);
178 if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) {
179 dev_err(&dev->dev, "virtio: device refuses features: %x\n",
180 status);
181 return -ENODEV;
182 }
183 return 0;
184}
185
186static int virtio_dev_probe(struct device *_d)
187{
188 int err, i;
189 struct virtio_device *dev = dev_to_virtio(_d);
190 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
191 u64 device_features;
192 u64 driver_features;
193 u64 driver_features_legacy;
194
195 /* We have a driver! */
196 add_status(dev, VIRTIO_CONFIG_S_DRIVER);
197
198 /* Figure out what features the device supports. */
199 device_features = dev->config->get_features(dev);
200
201 /* Figure out what features the driver supports. */
202 driver_features = 0;
203 for (i = 0; i < drv->feature_table_size; i++) {
204 unsigned int f = drv->feature_table[i];
205 BUG_ON(f >= 64);
206 driver_features |= (1ULL << f);
207 }
208
209 /* Some drivers have a separate feature table for virtio v1.0 */
210 if (drv->feature_table_legacy) {
211 driver_features_legacy = 0;
212 for (i = 0; i < drv->feature_table_size_legacy; i++) {
213 unsigned int f = drv->feature_table_legacy[i];
214 BUG_ON(f >= 64);
215 driver_features_legacy |= (1ULL << f);
216 }
217 } else {
218 driver_features_legacy = driver_features;
219 }
220
221 if (device_features & (1ULL << VIRTIO_F_VERSION_1))
222 dev->features = driver_features & device_features;
223 else
224 dev->features = driver_features_legacy & device_features;
225
226 /* Transport features always preserved to pass to finalize_features. */
227 for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
228 if (device_features & (1ULL << i))
229 __virtio_set_bit(dev, i);
230
231 err = virtio_finalize_features(dev);
232 if (err)
233 goto err;
234
235 err = drv->probe(dev);
236 if (err)
237 goto err;
238
239 /* If probe didn't do it, mark device DRIVER_OK ourselves. */
240 if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK))
241 virtio_device_ready(dev);
242
243 if (drv->scan)
244 drv->scan(dev);
245
246 virtio_config_enable(dev);
247
248 return 0;
249err:
250 add_status(dev, VIRTIO_CONFIG_S_FAILED);
251 return err;
252
253}
254
255static int virtio_dev_remove(struct device *_d)
256{
257 struct virtio_device *dev = dev_to_virtio(_d);
258 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
259
260 virtio_config_disable(dev);
261
262 drv->remove(dev);
263
264 /* Driver should have reset device. */
265 WARN_ON_ONCE(dev->config->get_status(dev));
266
267 /* Acknowledge the device's existence again. */
268 add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
269 return 0;
270}
271
272static struct bus_type virtio_bus = {
273 .name = "virtio",
274 .match = virtio_dev_match,
275 .dev_groups = virtio_dev_groups,
276 .uevent = virtio_uevent,
277 .probe = virtio_dev_probe,
278 .remove = virtio_dev_remove,
279};
280
281int register_virtio_driver(struct virtio_driver *driver)
282{
283 /* Catch this early. */
284 BUG_ON(driver->feature_table_size && !driver->feature_table);
285 driver->driver.bus = &virtio_bus;
286 return driver_register(&driver->driver);
287}
288EXPORT_SYMBOL_GPL(register_virtio_driver);
289
290void unregister_virtio_driver(struct virtio_driver *driver)
291{
292 driver_unregister(&driver->driver);
293}
294EXPORT_SYMBOL_GPL(unregister_virtio_driver);
295
296int register_virtio_device(struct virtio_device *dev)
297{
298 int err;
299
300 dev->dev.bus = &virtio_bus;
301
302 /* Assign a unique device index and hence name. */
303 err = ida_simple_get(&virtio_index_ida, 0, 0, GFP_KERNEL);
304 if (err < 0)
305 goto out;
306
307 dev->index = err;
308 dev_set_name(&dev->dev, "virtio%u", dev->index);
309
310 spin_lock_init(&dev->config_lock);
311 dev->config_enabled = false;
312 dev->config_change_pending = false;
313
314 /* We always start by resetting the device, in case a previous
315 * driver messed it up. This also tests that code path a little. */
316 dev->config->reset(dev);
317
318 /* Acknowledge that we've seen the device. */
319 add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
320
321 INIT_LIST_HEAD(&dev->vqs);
322
323 /* device_register() causes the bus infrastructure to look for a
324 * matching driver. */
325 err = device_register(&dev->dev);
326out:
327 if (err)
328 add_status(dev, VIRTIO_CONFIG_S_FAILED);
329 return err;
330}
331EXPORT_SYMBOL_GPL(register_virtio_device);
332
333void unregister_virtio_device(struct virtio_device *dev)
334{
335 int index = dev->index; /* save for after device release */
336
337 device_unregister(&dev->dev);
338 ida_simple_remove(&virtio_index_ida, index);
339}
340EXPORT_SYMBOL_GPL(unregister_virtio_device);
341
342#ifdef CONFIG_PM_SLEEP
343int virtio_device_freeze(struct virtio_device *dev)
344{
345 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
346
347 virtio_config_disable(dev);
348
349 dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED;
350
351 if (drv && drv->freeze)
352 return drv->freeze(dev);
353
354 return 0;
355}
356EXPORT_SYMBOL_GPL(virtio_device_freeze);
357
358int virtio_device_restore(struct virtio_device *dev)
359{
360 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
361 int ret;
362
363 /* We always start by resetting the device, in case a previous
364 * driver messed it up. */
365 dev->config->reset(dev);
366
367 /* Acknowledge that we've seen the device. */
368 add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
369
370 /* Maybe driver failed before freeze.
371 * Restore the failed status, for debugging. */
372 if (dev->failed)
373 add_status(dev, VIRTIO_CONFIG_S_FAILED);
374
375 if (!drv)
376 return 0;
377
378 /* We have a driver! */
379 add_status(dev, VIRTIO_CONFIG_S_DRIVER);
380
381 ret = virtio_finalize_features(dev);
382 if (ret)
383 goto err;
384
385 if (drv->restore) {
386 ret = drv->restore(dev);
387 if (ret)
388 goto err;
389 }
390
391 /* Finally, tell the device we're all set */
392 add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
393
394 virtio_config_enable(dev);
395
396 return 0;
397
398err:
399 add_status(dev, VIRTIO_CONFIG_S_FAILED);
400 return ret;
401}
402EXPORT_SYMBOL_GPL(virtio_device_restore);
403#endif
404
405static int virtio_init(void)
406{
407 if (bus_register(&virtio_bus) != 0)
408 panic("virtio bus registration failed");
409 return 0;
410}
411
412static void __exit virtio_exit(void)
413{
414 bus_unregister(&virtio_bus);
415 ida_destroy(&virtio_index_ida);
416}
417core_initcall(virtio_init);
418module_exit(virtio_exit);
419
420MODULE_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 const 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, struct module *owner)
366{
367 /* Catch this early. */
368 BUG_ON(driver->feature_table_size && !driver->feature_table);
369 driver->driver.bus = &virtio_bus;
370 driver->driver.owner = owner;
371
372 return driver_register(&driver->driver);
373}
374EXPORT_SYMBOL_GPL(__register_virtio_driver);
375
376void unregister_virtio_driver(struct virtio_driver *driver)
377{
378 driver_unregister(&driver->driver);
379}
380EXPORT_SYMBOL_GPL(unregister_virtio_driver);
381
382static int virtio_device_of_init(struct virtio_device *dev)
383{
384 struct device_node *np, *pnode = dev_of_node(dev->dev.parent);
385 char compat[] = "virtio,deviceXXXXXXXX";
386 int ret, count;
387
388 if (!pnode)
389 return 0;
390
391 count = of_get_available_child_count(pnode);
392 if (!count)
393 return 0;
394
395 /* There can be only 1 child node */
396 if (WARN_ON(count > 1))
397 return -EINVAL;
398
399 np = of_get_next_available_child(pnode, NULL);
400 if (WARN_ON(!np))
401 return -ENODEV;
402
403 ret = snprintf(compat, sizeof(compat), "virtio,device%x", dev->id.device);
404 BUG_ON(ret >= sizeof(compat));
405
406 /*
407 * On powerpc/pseries virtio devices are PCI devices so PCI
408 * vendor/device ids play the role of the "compatible" property.
409 * Simply don't init of_node in this case.
410 */
411 if (!of_device_is_compatible(np, compat)) {
412 ret = 0;
413 goto out;
414 }
415
416 dev->dev.of_node = np;
417 return 0;
418
419out:
420 of_node_put(np);
421 return ret;
422}
423
424/**
425 * register_virtio_device - register virtio device
426 * @dev : virtio device to be registered
427 *
428 * On error, the caller must call put_device on &@dev->dev (and not kfree),
429 * as another code path may have obtained a reference to @dev.
430 *
431 * Returns: 0 on suceess, -error on failure
432 */
433int register_virtio_device(struct virtio_device *dev)
434{
435 int err;
436
437 dev->dev.bus = &virtio_bus;
438 device_initialize(&dev->dev);
439
440 /* Assign a unique device index and hence name. */
441 err = ida_alloc(&virtio_index_ida, GFP_KERNEL);
442 if (err < 0)
443 goto out;
444
445 dev->index = err;
446 err = dev_set_name(&dev->dev, "virtio%u", dev->index);
447 if (err)
448 goto out_ida_remove;
449
450 err = virtio_device_of_init(dev);
451 if (err)
452 goto out_ida_remove;
453
454 spin_lock_init(&dev->config_lock);
455 dev->config_enabled = false;
456 dev->config_change_pending = false;
457
458 INIT_LIST_HEAD(&dev->vqs);
459 spin_lock_init(&dev->vqs_list_lock);
460
461 /* We always start by resetting the device, in case a previous
462 * driver messed it up. This also tests that code path a little. */
463 virtio_reset_device(dev);
464
465 /* Acknowledge that we've seen the device. */
466 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
467
468 /*
469 * device_add() causes the bus infrastructure to look for a matching
470 * driver.
471 */
472 err = device_add(&dev->dev);
473 if (err)
474 goto out_of_node_put;
475
476 return 0;
477
478out_of_node_put:
479 of_node_put(dev->dev.of_node);
480out_ida_remove:
481 ida_free(&virtio_index_ida, dev->index);
482out:
483 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
484 return err;
485}
486EXPORT_SYMBOL_GPL(register_virtio_device);
487
488bool is_virtio_device(struct device *dev)
489{
490 return dev->bus == &virtio_bus;
491}
492EXPORT_SYMBOL_GPL(is_virtio_device);
493
494void unregister_virtio_device(struct virtio_device *dev)
495{
496 int index = dev->index; /* save for after device release */
497
498 device_unregister(&dev->dev);
499 ida_free(&virtio_index_ida, index);
500}
501EXPORT_SYMBOL_GPL(unregister_virtio_device);
502
503#ifdef CONFIG_PM_SLEEP
504int virtio_device_freeze(struct virtio_device *dev)
505{
506 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
507 int ret;
508
509 virtio_config_disable(dev);
510
511 dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED;
512
513 if (drv && drv->freeze) {
514 ret = drv->freeze(dev);
515 if (ret) {
516 virtio_config_enable(dev);
517 return ret;
518 }
519 }
520
521 if (dev->config->destroy_avq)
522 dev->config->destroy_avq(dev);
523
524 return 0;
525}
526EXPORT_SYMBOL_GPL(virtio_device_freeze);
527
528int virtio_device_restore(struct virtio_device *dev)
529{
530 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
531 int ret;
532
533 /* We always start by resetting the device, in case a previous
534 * driver messed it up. */
535 virtio_reset_device(dev);
536
537 /* Acknowledge that we've seen the device. */
538 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
539
540 /* Maybe driver failed before freeze.
541 * Restore the failed status, for debugging. */
542 if (dev->failed)
543 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
544
545 if (!drv)
546 return 0;
547
548 /* We have a driver! */
549 virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER);
550
551 ret = dev->config->finalize_features(dev);
552 if (ret)
553 goto err;
554
555 ret = virtio_features_ok(dev);
556 if (ret)
557 goto err;
558
559 if (dev->config->create_avq) {
560 ret = dev->config->create_avq(dev);
561 if (ret)
562 goto err;
563 }
564
565 if (drv->restore) {
566 ret = drv->restore(dev);
567 if (ret)
568 goto err_restore;
569 }
570
571 /* If restore didn't do it, mark device DRIVER_OK ourselves. */
572 if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK))
573 virtio_device_ready(dev);
574
575 virtio_config_enable(dev);
576
577 return 0;
578
579err_restore:
580 if (dev->config->destroy_avq)
581 dev->config->destroy_avq(dev);
582err:
583 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
584 return ret;
585}
586EXPORT_SYMBOL_GPL(virtio_device_restore);
587#endif
588
589static int virtio_init(void)
590{
591 if (bus_register(&virtio_bus) != 0)
592 panic("virtio bus registration failed");
593 return 0;
594}
595
596static void __exit virtio_exit(void)
597{
598 bus_unregister(&virtio_bus);
599 ida_destroy(&virtio_index_ida);
600}
601core_initcall(virtio_init);
602module_exit(virtio_exit);
603
604MODULE_LICENSE("GPL");