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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#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
103void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
104 unsigned int fbit)
105{
106 unsigned int i;
107 struct virtio_driver *drv = drv_to_virtio(vdev->dev.driver);
108
109 for (i = 0; i < drv->feature_table_size; i++)
110 if (drv->feature_table[i] == fbit)
111 return;
112
113 if (drv->feature_table_legacy) {
114 for (i = 0; i < drv->feature_table_size_legacy; i++)
115 if (drv->feature_table_legacy[i] == fbit)
116 return;
117 }
118
119 BUG();
120}
121EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature);
122
123static void __virtio_config_changed(struct virtio_device *dev)
124{
125 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
126
127 if (!dev->config_enabled)
128 dev->config_change_pending = true;
129 else if (drv && drv->config_changed)
130 drv->config_changed(dev);
131}
132
133void virtio_config_changed(struct virtio_device *dev)
134{
135 unsigned long flags;
136
137 spin_lock_irqsave(&dev->config_lock, flags);
138 __virtio_config_changed(dev);
139 spin_unlock_irqrestore(&dev->config_lock, flags);
140}
141EXPORT_SYMBOL_GPL(virtio_config_changed);
142
143void virtio_config_disable(struct virtio_device *dev)
144{
145 spin_lock_irq(&dev->config_lock);
146 dev->config_enabled = false;
147 spin_unlock_irq(&dev->config_lock);
148}
149EXPORT_SYMBOL_GPL(virtio_config_disable);
150
151void virtio_config_enable(struct virtio_device *dev)
152{
153 spin_lock_irq(&dev->config_lock);
154 dev->config_enabled = true;
155 if (dev->config_change_pending)
156 __virtio_config_changed(dev);
157 dev->config_change_pending = false;
158 spin_unlock_irq(&dev->config_lock);
159}
160EXPORT_SYMBOL_GPL(virtio_config_enable);
161
162void virtio_add_status(struct virtio_device *dev, unsigned int status)
163{
164 dev->config->set_status(dev, dev->config->get_status(dev) | status);
165}
166EXPORT_SYMBOL_GPL(virtio_add_status);
167
168int virtio_finalize_features(struct virtio_device *dev)
169{
170 int ret = dev->config->finalize_features(dev);
171 unsigned status;
172
173 if (ret)
174 return ret;
175
176 if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1))
177 return 0;
178
179 virtio_add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK);
180 status = dev->config->get_status(dev);
181 if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) {
182 dev_err(&dev->dev, "virtio: device refuses features: %x\n",
183 status);
184 return -ENODEV;
185 }
186 return 0;
187}
188EXPORT_SYMBOL_GPL(virtio_finalize_features);
189
190static int virtio_dev_probe(struct device *_d)
191{
192 int err, i;
193 struct virtio_device *dev = dev_to_virtio(_d);
194 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
195 u64 device_features;
196 u64 driver_features;
197 u64 driver_features_legacy;
198
199 /* We have a driver! */
200 virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER);
201
202 /* Figure out what features the device supports. */
203 device_features = dev->config->get_features(dev);
204
205 /* Figure out what features the driver supports. */
206 driver_features = 0;
207 for (i = 0; i < drv->feature_table_size; i++) {
208 unsigned int f = drv->feature_table[i];
209 BUG_ON(f >= 64);
210 driver_features |= (1ULL << f);
211 }
212
213 /* Some drivers have a separate feature table for virtio v1.0 */
214 if (drv->feature_table_legacy) {
215 driver_features_legacy = 0;
216 for (i = 0; i < drv->feature_table_size_legacy; i++) {
217 unsigned int f = drv->feature_table_legacy[i];
218 BUG_ON(f >= 64);
219 driver_features_legacy |= (1ULL << f);
220 }
221 } else {
222 driver_features_legacy = driver_features;
223 }
224
225 if (device_features & (1ULL << VIRTIO_F_VERSION_1))
226 dev->features = driver_features & device_features;
227 else
228 dev->features = driver_features_legacy & device_features;
229
230 /* Transport features always preserved to pass to finalize_features. */
231 for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
232 if (device_features & (1ULL << i))
233 __virtio_set_bit(dev, i);
234
235 if (drv->validate) {
236 err = drv->validate(dev);
237 if (err)
238 goto err;
239 }
240
241 err = virtio_finalize_features(dev);
242 if (err)
243 goto err;
244
245 err = drv->probe(dev);
246 if (err)
247 goto err;
248
249 /* If probe didn't do it, mark device DRIVER_OK ourselves. */
250 if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK))
251 virtio_device_ready(dev);
252
253 if (drv->scan)
254 drv->scan(dev);
255
256 virtio_config_enable(dev);
257
258 return 0;
259err:
260 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
261 return err;
262
263}
264
265static int virtio_dev_remove(struct device *_d)
266{
267 struct virtio_device *dev = dev_to_virtio(_d);
268 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
269
270 virtio_config_disable(dev);
271
272 drv->remove(dev);
273
274 /* Driver should have reset device. */
275 WARN_ON_ONCE(dev->config->get_status(dev));
276
277 /* Acknowledge the device's existence again. */
278 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
279 return 0;
280}
281
282static struct bus_type virtio_bus = {
283 .name = "virtio",
284 .match = virtio_dev_match,
285 .dev_groups = virtio_dev_groups,
286 .uevent = virtio_uevent,
287 .probe = virtio_dev_probe,
288 .remove = virtio_dev_remove,
289};
290
291int register_virtio_driver(struct virtio_driver *driver)
292{
293 /* Catch this early. */
294 BUG_ON(driver->feature_table_size && !driver->feature_table);
295 driver->driver.bus = &virtio_bus;
296 return driver_register(&driver->driver);
297}
298EXPORT_SYMBOL_GPL(register_virtio_driver);
299
300void unregister_virtio_driver(struct virtio_driver *driver)
301{
302 driver_unregister(&driver->driver);
303}
304EXPORT_SYMBOL_GPL(unregister_virtio_driver);
305
306/**
307 * register_virtio_device - register virtio device
308 * @dev : virtio device to be registered
309 *
310 * On error, the caller must call put_device on &@dev->dev (and not kfree),
311 * as another code path may have obtained a reference to @dev.
312 *
313 * Returns: 0 on suceess, -error on failure
314 */
315int register_virtio_device(struct virtio_device *dev)
316{
317 int err;
318
319 dev->dev.bus = &virtio_bus;
320 device_initialize(&dev->dev);
321
322 /* Assign a unique device index and hence name. */
323 err = ida_simple_get(&virtio_index_ida, 0, 0, GFP_KERNEL);
324 if (err < 0)
325 goto out;
326
327 dev->index = err;
328 dev_set_name(&dev->dev, "virtio%u", dev->index);
329
330 spin_lock_init(&dev->config_lock);
331 dev->config_enabled = false;
332 dev->config_change_pending = false;
333
334 /* We always start by resetting the device, in case a previous
335 * driver messed it up. This also tests that code path a little. */
336 dev->config->reset(dev);
337
338 /* Acknowledge that we've seen the device. */
339 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
340
341 INIT_LIST_HEAD(&dev->vqs);
342
343 /*
344 * device_add() causes the bus infrastructure to look for a matching
345 * driver.
346 */
347 err = device_add(&dev->dev);
348 if (err)
349 ida_simple_remove(&virtio_index_ida, dev->index);
350out:
351 if (err)
352 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
353 return err;
354}
355EXPORT_SYMBOL_GPL(register_virtio_device);
356
357void unregister_virtio_device(struct virtio_device *dev)
358{
359 int index = dev->index; /* save for after device release */
360
361 device_unregister(&dev->dev);
362 ida_simple_remove(&virtio_index_ida, index);
363}
364EXPORT_SYMBOL_GPL(unregister_virtio_device);
365
366#ifdef CONFIG_PM_SLEEP
367int virtio_device_freeze(struct virtio_device *dev)
368{
369 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
370
371 virtio_config_disable(dev);
372
373 dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED;
374
375 if (drv && drv->freeze)
376 return drv->freeze(dev);
377
378 return 0;
379}
380EXPORT_SYMBOL_GPL(virtio_device_freeze);
381
382int virtio_device_restore(struct virtio_device *dev)
383{
384 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
385 int ret;
386
387 /* We always start by resetting the device, in case a previous
388 * driver messed it up. */
389 dev->config->reset(dev);
390
391 /* Acknowledge that we've seen the device. */
392 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
393
394 /* Maybe driver failed before freeze.
395 * Restore the failed status, for debugging. */
396 if (dev->failed)
397 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
398
399 if (!drv)
400 return 0;
401
402 /* We have a driver! */
403 virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER);
404
405 ret = virtio_finalize_features(dev);
406 if (ret)
407 goto err;
408
409 if (drv->restore) {
410 ret = drv->restore(dev);
411 if (ret)
412 goto err;
413 }
414
415 /* Finally, tell the device we're all set */
416 virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
417
418 virtio_config_enable(dev);
419
420 return 0;
421
422err:
423 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
424 return ret;
425}
426EXPORT_SYMBOL_GPL(virtio_device_restore);
427#endif
428
429static int virtio_init(void)
430{
431 if (bus_register(&virtio_bus) != 0)
432 panic("virtio bus registration failed");
433 return 0;
434}
435
436static void __exit virtio_exit(void)
437{
438 bus_unregister(&virtio_bus);
439 ida_destroy(&virtio_index_ida);
440}
441core_initcall(virtio_init);
442module_exit(virtio_exit);
443
444MODULE_LICENSE("GPL");