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 /* Do some validation, then set FEATURES_OK */
169 static int virtio_features_ok(struct virtio_device *dev)
173 if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1))
176 virtio_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",
186 static int virtio_dev_probe(struct device *_d)
189 struct virtio_device *dev = dev_to_virtio(_d);
190 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
193 u64 driver_features_legacy;
195 /* We have a driver! */
196 virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER);
198 /* Figure out what features the device supports. */
199 device_features = dev->config->get_features(dev);
201 /* Figure out what features the driver supports. */
203 for (i = 0; i < drv->feature_table_size; i++) {
204 unsigned int f = drv->feature_table[i];
206 driver_features |= (1ULL << f);
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];
215 driver_features_legacy |= (1ULL << f);
218 driver_features_legacy = driver_features;
221 if (device_features & (1ULL << VIRTIO_F_VERSION_1))
222 dev->features = driver_features & device_features;
224 dev->features = driver_features_legacy & device_features;
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);
231 err = dev->config->finalize_features(dev);
236 u64 features = dev->features;
238 err = drv->validate(dev);
242 /* Did validation change any features? Then write them again. */
243 if (features != dev->features) {
244 err = dev->config->finalize_features(dev);
250 err = virtio_features_ok(dev);
254 err = drv->probe(dev);
258 /* If probe didn't do it, mark device DRIVER_OK ourselves. */
259 if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK))
260 virtio_device_ready(dev);
265 virtio_config_enable(dev);
269 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
274 static int virtio_dev_remove(struct device *_d)
276 struct virtio_device *dev = dev_to_virtio(_d);
277 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
279 virtio_config_disable(dev);
283 /* Driver should have reset device. */
284 WARN_ON_ONCE(dev->config->get_status(dev));
286 /* Acknowledge the device's existence again. */
287 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
291 static struct bus_type virtio_bus = {
293 .match = virtio_dev_match,
294 .dev_groups = virtio_dev_groups,
295 .uevent = virtio_uevent,
296 .probe = virtio_dev_probe,
297 .remove = virtio_dev_remove,
300 int register_virtio_driver(struct virtio_driver *driver)
302 /* Catch this early. */
303 BUG_ON(driver->feature_table_size && !driver->feature_table);
304 driver->driver.bus = &virtio_bus;
305 return driver_register(&driver->driver);
307 EXPORT_SYMBOL_GPL(register_virtio_driver);
309 void unregister_virtio_driver(struct virtio_driver *driver)
311 driver_unregister(&driver->driver);
313 EXPORT_SYMBOL_GPL(unregister_virtio_driver);
316 * register_virtio_device - register virtio device
317 * @dev : virtio device to be registered
319 * On error, the caller must call put_device on &@dev->dev (and not kfree),
320 * as another code path may have obtained a reference to @dev.
322 * Returns: 0 on suceess, -error on failure
324 int register_virtio_device(struct virtio_device *dev)
328 dev->dev.bus = &virtio_bus;
329 device_initialize(&dev->dev);
331 /* Assign a unique device index and hence name. */
332 err = ida_simple_get(&virtio_index_ida, 0, 0, GFP_KERNEL);
337 dev_set_name(&dev->dev, "virtio%u", dev->index);
339 spin_lock_init(&dev->config_lock);
340 dev->config_enabled = false;
341 dev->config_change_pending = false;
343 /* We always start by resetting the device, in case a previous
344 * driver messed it up. This also tests that code path a little. */
345 dev->config->reset(dev);
347 /* Acknowledge that we've seen the device. */
348 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
350 INIT_LIST_HEAD(&dev->vqs);
353 * device_add() causes the bus infrastructure to look for a matching
356 err = device_add(&dev->dev);
358 ida_simple_remove(&virtio_index_ida, dev->index);
361 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
364 EXPORT_SYMBOL_GPL(register_virtio_device);
366 void unregister_virtio_device(struct virtio_device *dev)
368 int index = dev->index; /* save for after device release */
370 device_unregister(&dev->dev);
371 ida_simple_remove(&virtio_index_ida, index);
373 EXPORT_SYMBOL_GPL(unregister_virtio_device);
375 #ifdef CONFIG_PM_SLEEP
376 int virtio_device_freeze(struct virtio_device *dev)
378 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
380 virtio_config_disable(dev);
382 dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED;
384 if (drv && drv->freeze)
385 return drv->freeze(dev);
389 EXPORT_SYMBOL_GPL(virtio_device_freeze);
391 int virtio_device_restore(struct virtio_device *dev)
393 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
396 /* We always start by resetting the device, in case a previous
397 * driver messed it up. */
398 dev->config->reset(dev);
400 /* Acknowledge that we've seen the device. */
401 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
403 /* Maybe driver failed before freeze.
404 * Restore the failed status, for debugging. */
406 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
411 /* We have a driver! */
412 virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER);
414 ret = dev->config->finalize_features(dev);
418 ret = virtio_features_ok(dev);
423 ret = drv->restore(dev);
428 /* Finally, tell the device we're all set */
429 virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
431 virtio_config_enable(dev);
436 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
439 EXPORT_SYMBOL_GPL(virtio_device_restore);
442 static int virtio_init(void)
444 if (bus_register(&virtio_bus) != 0)
445 panic("virtio bus registration failed");
449 static void __exit virtio_exit(void)
451 bus_unregister(&virtio_bus);
452 ida_destroy(&virtio_index_ida);
454 core_initcall(virtio_init);
455 module_exit(virtio_exit);
457 MODULE_LICENSE("GPL");