1 #include <linux/virtio.h>
2 #include <linux/spinlock.h>
3 #include <linux/virtio_config.h>
4 #include <linux/module.h>
6 #include <uapi/linux/virtio_ids.h>
8 /* Unique numbering for virtio devices. */
9 static DEFINE_IDA(virtio_index_ida);
11 static ssize_t device_show(struct device *_d,
12 struct device_attribute *attr, char *buf)
14 struct virtio_device *dev = dev_to_virtio(_d);
15 return sprintf(buf, "0x%04x\n", dev->id.device);
17 static DEVICE_ATTR_RO(device);
19 static ssize_t vendor_show(struct device *_d,
20 struct device_attribute *attr, char *buf)
22 struct virtio_device *dev = dev_to_virtio(_d);
23 return sprintf(buf, "0x%04x\n", dev->id.vendor);
25 static DEVICE_ATTR_RO(vendor);
27 static ssize_t status_show(struct device *_d,
28 struct device_attribute *attr, char *buf)
30 struct virtio_device *dev = dev_to_virtio(_d);
31 return sprintf(buf, "0x%08x\n", dev->config->get_status(dev));
33 static DEVICE_ATTR_RO(status);
35 static ssize_t modalias_show(struct device *_d,
36 struct device_attribute *attr, char *buf)
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);
42 static DEVICE_ATTR_RO(modalias);
44 static ssize_t features_show(struct device *_d,
45 struct device_attribute *attr, char *buf)
47 struct virtio_device *dev = dev_to_virtio(_d);
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");
59 static DEVICE_ATTR_RO(features);
61 static 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,
69 ATTRIBUTE_GROUPS(virtio_dev);
71 static inline int virtio_id_match(const struct virtio_device *dev,
72 const struct virtio_device_id *id)
74 if (id->device != dev->id.device && id->device != VIRTIO_DEV_ANY_ID)
77 return id->vendor == VIRTIO_DEV_ANY_ID || id->vendor == dev->id.vendor;
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(). */
82 static int virtio_dev_match(struct device *_dv, struct device_driver *_dr)
85 struct virtio_device *dev = dev_to_virtio(_dv);
86 const struct virtio_device_id *ids;
88 ids = drv_to_virtio(_dr)->id_table;
89 for (i = 0; ids[i].device; i++)
90 if (virtio_id_match(dev, &ids[i]))
95 static int virtio_uevent(struct device *_dv, struct kobj_uevent_env *env)
97 struct virtio_device *dev = dev_to_virtio(_dv);
99 return add_uevent_var(env, "MODALIAS=virtio:d%08Xv%08X",
100 dev->id.device, dev->id.vendor);
103 void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
107 struct virtio_driver *drv = drv_to_virtio(vdev->dev.driver);
109 for (i = 0; i < drv->feature_table_size; i++)
110 if (drv->feature_table[i] == fbit)
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)
121 EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature);
123 static void __virtio_config_changed(struct virtio_device *dev)
125 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
127 if (!dev->config_enabled)
128 dev->config_change_pending = true;
129 else if (drv && drv->config_changed)
130 drv->config_changed(dev);
133 void virtio_config_changed(struct virtio_device *dev)
137 spin_lock_irqsave(&dev->config_lock, flags);
138 __virtio_config_changed(dev);
139 spin_unlock_irqrestore(&dev->config_lock, flags);
141 EXPORT_SYMBOL_GPL(virtio_config_changed);
143 void virtio_config_disable(struct virtio_device *dev)
145 spin_lock_irq(&dev->config_lock);
146 dev->config_enabled = false;
147 spin_unlock_irq(&dev->config_lock);
149 EXPORT_SYMBOL_GPL(virtio_config_disable);
151 void virtio_config_enable(struct virtio_device *dev)
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);
160 EXPORT_SYMBOL_GPL(virtio_config_enable);
162 void virtio_add_status(struct virtio_device *dev, unsigned int status)
164 dev->config->set_status(dev, dev->config->get_status(dev) | status);
166 EXPORT_SYMBOL_GPL(virtio_add_status);
168 int virtio_finalize_features(struct virtio_device *dev)
170 int ret = dev->config->finalize_features(dev);
176 if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1))
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",
188 EXPORT_SYMBOL_GPL(virtio_finalize_features);
190 static int virtio_dev_probe(struct device *_d)
193 struct virtio_device *dev = dev_to_virtio(_d);
194 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
197 u64 driver_features_legacy;
199 /* We have a driver! */
200 virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER);
202 /* Figure out what features the device supports. */
203 device_features = dev->config->get_features(dev);
205 /* Figure out what features the driver supports. */
207 for (i = 0; i < drv->feature_table_size; i++) {
208 unsigned int f = drv->feature_table[i];
210 driver_features |= (1ULL << f);
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];
219 driver_features_legacy |= (1ULL << f);
222 driver_features_legacy = driver_features;
226 * Some devices detect legacy solely via F_VERSION_1. Write
227 * F_VERSION_1 to force LE config space accesses before FEATURES_OK for
230 if (drv->validate && !virtio_legacy_is_little_endian()
231 && device_features & BIT_ULL(VIRTIO_F_VERSION_1)) {
232 dev->features = BIT_ULL(VIRTIO_F_VERSION_1);
233 dev->config->finalize_features(dev);
236 if (device_features & (1ULL << VIRTIO_F_VERSION_1))
237 dev->features = driver_features & device_features;
239 dev->features = driver_features_legacy & device_features;
241 /* Transport features always preserved to pass to finalize_features. */
242 for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
243 if (device_features & (1ULL << i))
244 __virtio_set_bit(dev, i);
247 err = drv->validate(dev);
252 err = virtio_finalize_features(dev);
256 err = drv->probe(dev);
260 /* If probe didn't do it, mark device DRIVER_OK ourselves. */
261 if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK))
262 virtio_device_ready(dev);
267 virtio_config_enable(dev);
271 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
276 static int virtio_dev_remove(struct device *_d)
278 struct virtio_device *dev = dev_to_virtio(_d);
279 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
281 virtio_config_disable(dev);
285 /* Driver should have reset device. */
286 WARN_ON_ONCE(dev->config->get_status(dev));
288 /* Acknowledge the device's existence again. */
289 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
293 static struct bus_type virtio_bus = {
295 .match = virtio_dev_match,
296 .dev_groups = virtio_dev_groups,
297 .uevent = virtio_uevent,
298 .probe = virtio_dev_probe,
299 .remove = virtio_dev_remove,
302 int register_virtio_driver(struct virtio_driver *driver)
304 /* Catch this early. */
305 BUG_ON(driver->feature_table_size && !driver->feature_table);
306 driver->driver.bus = &virtio_bus;
307 return driver_register(&driver->driver);
309 EXPORT_SYMBOL_GPL(register_virtio_driver);
311 void unregister_virtio_driver(struct virtio_driver *driver)
313 driver_unregister(&driver->driver);
315 EXPORT_SYMBOL_GPL(unregister_virtio_driver);
317 int register_virtio_device(struct virtio_device *dev)
321 dev->dev.bus = &virtio_bus;
323 /* Assign a unique device index and hence name. */
324 err = ida_simple_get(&virtio_index_ida, 0, 0, GFP_KERNEL);
329 dev_set_name(&dev->dev, "virtio%u", dev->index);
331 spin_lock_init(&dev->config_lock);
332 dev->config_enabled = false;
333 dev->config_change_pending = false;
335 /* We always start by resetting the device, in case a previous
336 * driver messed it up. This also tests that code path a little. */
337 dev->config->reset(dev);
339 /* Acknowledge that we've seen the device. */
340 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
342 INIT_LIST_HEAD(&dev->vqs);
344 /* device_register() causes the bus infrastructure to look for a
345 * matching driver. */
346 err = device_register(&dev->dev);
348 ida_simple_remove(&virtio_index_ida, dev->index);
351 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
354 EXPORT_SYMBOL_GPL(register_virtio_device);
356 void unregister_virtio_device(struct virtio_device *dev)
358 int index = dev->index; /* save for after device release */
360 device_unregister(&dev->dev);
361 ida_simple_remove(&virtio_index_ida, index);
363 EXPORT_SYMBOL_GPL(unregister_virtio_device);
365 #ifdef CONFIG_PM_SLEEP
366 int virtio_device_freeze(struct virtio_device *dev)
368 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
370 virtio_config_disable(dev);
372 dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED;
374 if (drv && drv->freeze)
375 return drv->freeze(dev);
379 EXPORT_SYMBOL_GPL(virtio_device_freeze);
381 int virtio_device_restore(struct virtio_device *dev)
383 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
386 /* We always start by resetting the device, in case a previous
387 * driver messed it up. */
388 dev->config->reset(dev);
390 /* Acknowledge that we've seen the device. */
391 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
393 /* Maybe driver failed before freeze.
394 * Restore the failed status, for debugging. */
396 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
401 /* We have a driver! */
402 virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER);
404 ret = virtio_finalize_features(dev);
409 ret = drv->restore(dev);
414 /* Finally, tell the device we're all set */
415 virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
417 virtio_config_enable(dev);
422 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
425 EXPORT_SYMBOL_GPL(virtio_device_restore);
428 static int virtio_init(void)
430 if (bus_register(&virtio_bus) != 0)
431 panic("virtio bus registration failed");
435 static void __exit virtio_exit(void)
437 bus_unregister(&virtio_bus);
438 ida_destroy(&virtio_index_ida);
440 core_initcall(virtio_init);
441 module_exit(virtio_exit);
443 MODULE_LICENSE("GPL");