1 #include <linux/virtio.h>
2 #include <linux/spinlock.h>
3 #include <linux/virtio_config.h>
4 #include <linux/module.h>
7 /* Unique numbering for virtio devices. */
8 static DEFINE_IDA(virtio_index_ida);
10 static ssize_t device_show(struct device *_d,
11 struct device_attribute *attr, char *buf)
13 struct virtio_device *dev = dev_to_virtio(_d);
14 return sprintf(buf, "0x%04x\n", dev->id.device);
16 static ssize_t vendor_show(struct device *_d,
17 struct device_attribute *attr, char *buf)
19 struct virtio_device *dev = dev_to_virtio(_d);
20 return sprintf(buf, "0x%04x\n", dev->id.vendor);
22 static ssize_t status_show(struct device *_d,
23 struct device_attribute *attr, char *buf)
25 struct virtio_device *dev = dev_to_virtio(_d);
26 return sprintf(buf, "0x%08x\n", dev->config->get_status(dev));
28 static ssize_t modalias_show(struct device *_d,
29 struct device_attribute *attr, char *buf)
31 struct virtio_device *dev = dev_to_virtio(_d);
32 return sprintf(buf, "virtio:d%08Xv%08X\n",
33 dev->id.device, dev->id.vendor);
35 static ssize_t features_show(struct device *_d,
36 struct device_attribute *attr, char *buf)
38 struct virtio_device *dev = dev_to_virtio(_d);
42 /* We actually represent this as a bitstring, as it could be
43 * arbitrary length in future. */
44 for (i = 0; i < ARRAY_SIZE(dev->features)*BITS_PER_LONG; i++)
45 len += sprintf(buf+len, "%c",
46 test_bit(i, dev->features) ? '1' : '0');
47 len += sprintf(buf+len, "\n");
50 static struct device_attribute virtio_dev_attrs[] = {
59 static inline int virtio_id_match(const struct virtio_device *dev,
60 const struct virtio_device_id *id)
62 if (id->device != dev->id.device && id->device != VIRTIO_DEV_ANY_ID)
65 return id->vendor == VIRTIO_DEV_ANY_ID || id->vendor == dev->id.vendor;
68 /* This looks through all the IDs a driver claims to support. If any of them
69 * match, we return 1 and the kernel will call virtio_dev_probe(). */
70 static int virtio_dev_match(struct device *_dv, struct device_driver *_dr)
73 struct virtio_device *dev = dev_to_virtio(_dv);
74 const struct virtio_device_id *ids;
76 ids = drv_to_virtio(_dr)->id_table;
77 for (i = 0; ids[i].device; i++)
78 if (virtio_id_match(dev, &ids[i]))
83 static int virtio_uevent(struct device *_dv, struct kobj_uevent_env *env)
85 struct virtio_device *dev = dev_to_virtio(_dv);
87 return add_uevent_var(env, "MODALIAS=virtio:d%08Xv%08X",
88 dev->id.device, dev->id.vendor);
91 static void add_status(struct virtio_device *dev, unsigned status)
93 dev->config->set_status(dev, dev->config->get_status(dev) | status);
96 void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
100 struct virtio_driver *drv = drv_to_virtio(vdev->dev.driver);
102 for (i = 0; i < drv->feature_table_size; i++)
103 if (drv->feature_table[i] == fbit)
107 EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature);
109 static int virtio_dev_probe(struct device *_d)
112 struct virtio_device *dev = dev_to_virtio(_d);
113 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
116 /* We have a driver! */
117 add_status(dev, VIRTIO_CONFIG_S_DRIVER);
119 /* Figure out what features the device supports. */
120 device_features = dev->config->get_features(dev);
122 /* Features supported by both device and driver into dev->features. */
123 memset(dev->features, 0, sizeof(dev->features));
124 for (i = 0; i < drv->feature_table_size; i++) {
125 unsigned int f = drv->feature_table[i];
127 if (device_features & (1 << f))
128 set_bit(f, dev->features);
131 /* Transport features always preserved to pass to finalize_features. */
132 for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
133 if (device_features & (1 << i))
134 set_bit(i, dev->features);
136 dev->config->finalize_features(dev);
138 err = drv->probe(dev);
140 add_status(dev, VIRTIO_CONFIG_S_FAILED);
142 add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
150 static int virtio_dev_remove(struct device *_d)
152 struct virtio_device *dev = dev_to_virtio(_d);
153 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
157 /* Driver should have reset device. */
158 WARN_ON_ONCE(dev->config->get_status(dev));
160 /* Acknowledge the device's existence again. */
161 add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
165 static struct bus_type virtio_bus = {
167 .match = virtio_dev_match,
168 .dev_attrs = virtio_dev_attrs,
169 .uevent = virtio_uevent,
170 .probe = virtio_dev_probe,
171 .remove = virtio_dev_remove,
174 int register_virtio_driver(struct virtio_driver *driver)
176 /* Catch this early. */
177 BUG_ON(driver->feature_table_size && !driver->feature_table);
178 driver->driver.bus = &virtio_bus;
179 return driver_register(&driver->driver);
181 EXPORT_SYMBOL_GPL(register_virtio_driver);
183 void unregister_virtio_driver(struct virtio_driver *driver)
185 driver_unregister(&driver->driver);
187 EXPORT_SYMBOL_GPL(unregister_virtio_driver);
189 int register_virtio_device(struct virtio_device *dev)
193 dev->dev.bus = &virtio_bus;
195 /* Assign a unique device index and hence name. */
196 err = ida_simple_get(&virtio_index_ida, 0, 0, GFP_KERNEL);
201 dev_set_name(&dev->dev, "virtio%u", dev->index);
203 /* We always start by resetting the device, in case a previous
204 * driver messed it up. This also tests that code path a little. */
205 dev->config->reset(dev);
207 /* Acknowledge that we've seen the device. */
208 add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
210 INIT_LIST_HEAD(&dev->vqs);
212 /* device_register() causes the bus infrastructure to look for a
213 * matching driver. */
214 err = device_register(&dev->dev);
217 add_status(dev, VIRTIO_CONFIG_S_FAILED);
220 EXPORT_SYMBOL_GPL(register_virtio_device);
222 void unregister_virtio_device(struct virtio_device *dev)
224 int index = dev->index; /* save for after device release */
226 device_unregister(&dev->dev);
227 ida_simple_remove(&virtio_index_ida, index);
229 EXPORT_SYMBOL_GPL(unregister_virtio_device);
231 static int virtio_init(void)
233 if (bus_register(&virtio_bus) != 0)
234 panic("virtio bus registration failed");
238 static void __exit virtio_exit(void)
240 bus_unregister(&virtio_bus);
242 core_initcall(virtio_init);
243 module_exit(virtio_exit);
245 MODULE_LICENSE("GPL");