1 #include <linux/virtio.h>
2 #include <linux/spinlock.h>
3 #include <linux/virtio_config.h>
5 /* Unique numbering for virtio devices. */
6 static unsigned int dev_index;
8 static ssize_t device_show(struct device *_d,
9 struct device_attribute *attr, char *buf)
11 struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
12 return sprintf(buf, "%hu", dev->id.device);
14 static ssize_t vendor_show(struct device *_d,
15 struct device_attribute *attr, char *buf)
17 struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
18 return sprintf(buf, "%hu", dev->id.vendor);
20 static ssize_t status_show(struct device *_d,
21 struct device_attribute *attr, char *buf)
23 struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
24 return sprintf(buf, "0x%08x", dev->config->get_status(dev));
26 static ssize_t modalias_show(struct device *_d,
27 struct device_attribute *attr, char *buf)
29 struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
31 return sprintf(buf, "virtio:d%08Xv%08X\n",
32 dev->id.device, dev->id.vendor);
34 static struct device_attribute virtio_dev_attrs[] = {
42 static inline int virtio_id_match(const struct virtio_device *dev,
43 const struct virtio_device_id *id)
45 if (id->device != dev->id.device)
48 return id->vendor == VIRTIO_DEV_ANY_ID || id->vendor != dev->id.vendor;
51 /* This looks through all the IDs a driver claims to support. If any of them
52 * match, we return 1 and the kernel will call virtio_dev_probe(). */
53 static int virtio_dev_match(struct device *_dv, struct device_driver *_dr)
56 struct virtio_device *dev = container_of(_dv,struct virtio_device,dev);
57 const struct virtio_device_id *ids;
59 ids = container_of(_dr, struct virtio_driver, driver)->id_table;
60 for (i = 0; ids[i].device; i++)
61 if (virtio_id_match(dev, &ids[i]))
66 static int virtio_uevent(struct device *_dv, struct kobj_uevent_env *env)
68 struct virtio_device *dev = container_of(_dv,struct virtio_device,dev);
70 return add_uevent_var(env, "MODALIAS=virtio:d%08Xv%08X",
71 dev->id.device, dev->id.vendor);
74 static void add_status(struct virtio_device *dev, unsigned status)
76 dev->config->set_status(dev, dev->config->get_status(dev) | status);
79 void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
83 struct virtio_driver *drv = container_of(vdev->dev.driver,
84 struct virtio_driver, driver);
86 for (i = 0; i < drv->feature_table_size; i++)
87 if (drv->feature_table[i] == fbit)
91 EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature);
93 static int virtio_dev_probe(struct device *_d)
96 struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
97 struct virtio_driver *drv = container_of(dev->dev.driver,
98 struct virtio_driver, driver);
101 /* We have a driver! */
102 add_status(dev, VIRTIO_CONFIG_S_DRIVER);
104 /* Figure out what features the device supports. */
105 device_features = dev->config->get_features(dev);
107 /* Features supported by both device and driver into dev->features. */
108 memset(dev->features, 0, sizeof(dev->features));
109 for (i = 0; i < drv->feature_table_size; i++) {
110 unsigned int f = drv->feature_table[i];
112 if (device_features & (1 << f))
113 set_bit(f, dev->features);
116 /* Transport features always preserved to pass to finalize_features. */
117 for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
118 if (device_features & (1 << i))
119 set_bit(i, dev->features);
121 dev->config->finalize_features(dev);
123 err = drv->probe(dev);
125 add_status(dev, VIRTIO_CONFIG_S_FAILED);
127 add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
132 static int virtio_dev_remove(struct device *_d)
134 struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
135 struct virtio_driver *drv = container_of(dev->dev.driver,
136 struct virtio_driver, driver);
140 /* Driver should have reset device. */
141 BUG_ON(dev->config->get_status(dev));
143 /* Acknowledge the device's existence again. */
144 add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
148 static struct bus_type virtio_bus = {
150 .match = virtio_dev_match,
151 .dev_attrs = virtio_dev_attrs,
152 .uevent = virtio_uevent,
153 .probe = virtio_dev_probe,
154 .remove = virtio_dev_remove,
157 int register_virtio_driver(struct virtio_driver *driver)
159 /* Catch this early. */
160 BUG_ON(driver->feature_table_size && !driver->feature_table);
161 driver->driver.bus = &virtio_bus;
162 return driver_register(&driver->driver);
164 EXPORT_SYMBOL_GPL(register_virtio_driver);
166 void unregister_virtio_driver(struct virtio_driver *driver)
168 driver_unregister(&driver->driver);
170 EXPORT_SYMBOL_GPL(unregister_virtio_driver);
172 int register_virtio_device(struct virtio_device *dev)
176 dev->dev.bus = &virtio_bus;
178 /* Assign a unique device index and hence name. */
179 dev->index = dev_index++;
180 dev_set_name(&dev->dev, "virtio%u", dev->index);
182 /* We always start by resetting the device, in case a previous
183 * driver messed it up. This also tests that code path a little. */
184 dev->config->reset(dev);
186 /* Acknowledge that we've seen the device. */
187 add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
189 INIT_LIST_HEAD(&dev->vqs);
191 /* device_register() causes the bus infrastructure to look for a
192 * matching driver. */
193 err = device_register(&dev->dev);
195 add_status(dev, VIRTIO_CONFIG_S_FAILED);
198 EXPORT_SYMBOL_GPL(register_virtio_device);
200 void unregister_virtio_device(struct virtio_device *dev)
202 device_unregister(&dev->dev);
204 EXPORT_SYMBOL_GPL(unregister_virtio_device);
206 static int virtio_init(void)
208 if (bus_register(&virtio_bus) != 0)
209 panic("virtio bus registration failed");
213 static void __exit virtio_exit(void)
215 bus_unregister(&virtio_bus);
217 core_initcall(virtio_init);
218 module_exit(virtio_exit);
220 MODULE_LICENSE("GPL");