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 DEVICE_ATTR_RO(device);
18 static ssize_t vendor_show(struct device *_d,
19 struct device_attribute *attr, char *buf)
21 struct virtio_device *dev = dev_to_virtio(_d);
22 return sprintf(buf, "0x%04x\n", dev->id.vendor);
24 static DEVICE_ATTR_RO(vendor);
26 static ssize_t status_show(struct device *_d,
27 struct device_attribute *attr, char *buf)
29 struct virtio_device *dev = dev_to_virtio(_d);
30 return sprintf(buf, "0x%08x\n", dev->config->get_status(dev));
32 static DEVICE_ATTR_RO(status);
34 static ssize_t modalias_show(struct device *_d,
35 struct device_attribute *attr, char *buf)
37 struct virtio_device *dev = dev_to_virtio(_d);
38 return sprintf(buf, "virtio:d%08Xv%08X\n",
39 dev->id.device, dev->id.vendor);
41 static DEVICE_ATTR_RO(modalias);
43 static ssize_t features_show(struct device *_d,
44 struct device_attribute *attr, char *buf)
46 struct virtio_device *dev = dev_to_virtio(_d);
50 /* We actually represent this as a bitstring, as it could be
51 * arbitrary length in future. */
52 for (i = 0; i < ARRAY_SIZE(dev->features)*BITS_PER_LONG; i++)
53 len += sprintf(buf+len, "%c",
54 test_bit(i, dev->features) ? '1' : '0');
55 len += sprintf(buf+len, "\n");
58 static DEVICE_ATTR_RO(features);
60 static struct attribute *virtio_dev_attrs[] = {
61 &dev_attr_device.attr,
62 &dev_attr_vendor.attr,
63 &dev_attr_status.attr,
64 &dev_attr_modalias.attr,
65 &dev_attr_features.attr,
68 ATTRIBUTE_GROUPS(virtio_dev);
70 static inline int virtio_id_match(const struct virtio_device *dev,
71 const struct virtio_device_id *id)
73 if (id->device != dev->id.device && id->device != VIRTIO_DEV_ANY_ID)
76 return id->vendor == VIRTIO_DEV_ANY_ID || id->vendor == dev->id.vendor;
79 /* This looks through all the IDs a driver claims to support. If any of them
80 * match, we return 1 and the kernel will call virtio_dev_probe(). */
81 static int virtio_dev_match(struct device *_dv, struct device_driver *_dr)
84 struct virtio_device *dev = dev_to_virtio(_dv);
85 const struct virtio_device_id *ids;
87 ids = drv_to_virtio(_dr)->id_table;
88 for (i = 0; ids[i].device; i++)
89 if (virtio_id_match(dev, &ids[i]))
94 static int virtio_uevent(struct device *_dv, struct kobj_uevent_env *env)
96 struct virtio_device *dev = dev_to_virtio(_dv);
98 return add_uevent_var(env, "MODALIAS=virtio:d%08Xv%08X",
99 dev->id.device, dev->id.vendor);
102 static void add_status(struct virtio_device *dev, unsigned status)
104 dev->config->set_status(dev, dev->config->get_status(dev) | status);
107 void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
111 struct virtio_driver *drv = drv_to_virtio(vdev->dev.driver);
113 for (i = 0; i < drv->feature_table_size; i++)
114 if (drv->feature_table[i] == fbit)
118 EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature);
120 static void __virtio_config_changed(struct virtio_device *dev)
122 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
124 if (!dev->config_enabled)
125 dev->config_change_pending = true;
126 else if (drv && drv->config_changed)
127 drv->config_changed(dev);
130 void virtio_config_changed(struct virtio_device *dev)
134 spin_lock_irqsave(&dev->config_lock, flags);
135 __virtio_config_changed(dev);
136 spin_unlock_irqrestore(&dev->config_lock, flags);
138 EXPORT_SYMBOL_GPL(virtio_config_changed);
140 static void virtio_config_disable(struct virtio_device *dev)
142 spin_lock_irq(&dev->config_lock);
143 dev->config_enabled = false;
144 spin_unlock_irq(&dev->config_lock);
147 static void virtio_config_enable(struct virtio_device *dev)
149 spin_lock_irq(&dev->config_lock);
150 dev->config_enabled = true;
151 if (dev->config_change_pending)
152 __virtio_config_changed(dev);
153 dev->config_change_pending = false;
154 spin_unlock_irq(&dev->config_lock);
157 static int virtio_dev_probe(struct device *_d)
160 struct virtio_device *dev = dev_to_virtio(_d);
161 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
164 /* We have a driver! */
165 add_status(dev, VIRTIO_CONFIG_S_DRIVER);
167 /* Figure out what features the device supports. */
168 device_features = dev->config->get_features(dev);
170 /* Features supported by both device and driver into dev->features. */
171 memset(dev->features, 0, sizeof(dev->features));
172 for (i = 0; i < drv->feature_table_size; i++) {
173 unsigned int f = drv->feature_table[i];
175 if (device_features & (1 << f))
176 set_bit(f, dev->features);
179 /* Transport features always preserved to pass to finalize_features. */
180 for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
181 if (device_features & (1 << i))
182 set_bit(i, dev->features);
184 dev->config->finalize_features(dev);
186 err = drv->probe(dev);
188 add_status(dev, VIRTIO_CONFIG_S_FAILED);
190 add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
194 virtio_config_enable(dev);
200 static int virtio_dev_remove(struct device *_d)
202 struct virtio_device *dev = dev_to_virtio(_d);
203 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
205 virtio_config_disable(dev);
209 /* Driver should have reset device. */
210 WARN_ON_ONCE(dev->config->get_status(dev));
212 /* Acknowledge the device's existence again. */
213 add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
217 static struct bus_type virtio_bus = {
219 .match = virtio_dev_match,
220 .dev_groups = virtio_dev_groups,
221 .uevent = virtio_uevent,
222 .probe = virtio_dev_probe,
223 .remove = virtio_dev_remove,
226 int register_virtio_driver(struct virtio_driver *driver)
228 /* Catch this early. */
229 BUG_ON(driver->feature_table_size && !driver->feature_table);
230 driver->driver.bus = &virtio_bus;
231 return driver_register(&driver->driver);
233 EXPORT_SYMBOL_GPL(register_virtio_driver);
235 void unregister_virtio_driver(struct virtio_driver *driver)
237 driver_unregister(&driver->driver);
239 EXPORT_SYMBOL_GPL(unregister_virtio_driver);
241 int register_virtio_device(struct virtio_device *dev)
245 dev->dev.bus = &virtio_bus;
247 /* Assign a unique device index and hence name. */
248 err = ida_simple_get(&virtio_index_ida, 0, 0, GFP_KERNEL);
253 dev_set_name(&dev->dev, "virtio%u", dev->index);
255 spin_lock_init(&dev->config_lock);
256 dev->config_enabled = false;
257 dev->config_change_pending = false;
259 /* We always start by resetting the device, in case a previous
260 * driver messed it up. This also tests that code path a little. */
261 dev->config->reset(dev);
263 /* Acknowledge that we've seen the device. */
264 add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
266 INIT_LIST_HEAD(&dev->vqs);
268 /* device_register() causes the bus infrastructure to look for a
269 * matching driver. */
270 err = device_register(&dev->dev);
273 add_status(dev, VIRTIO_CONFIG_S_FAILED);
276 EXPORT_SYMBOL_GPL(register_virtio_device);
278 void unregister_virtio_device(struct virtio_device *dev)
280 int index = dev->index; /* save for after device release */
282 device_unregister(&dev->dev);
283 ida_simple_remove(&virtio_index_ida, index);
285 EXPORT_SYMBOL_GPL(unregister_virtio_device);
287 #ifdef CONFIG_PM_SLEEP
288 int virtio_device_freeze(struct virtio_device *dev)
290 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
292 virtio_config_disable(dev);
294 dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED;
296 if (drv && drv->freeze)
297 return drv->freeze(dev);
301 EXPORT_SYMBOL_GPL(virtio_device_freeze);
303 int virtio_device_restore(struct virtio_device *dev)
305 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
307 /* We always start by resetting the device, in case a previous
308 * driver messed it up. */
309 dev->config->reset(dev);
311 /* Acknowledge that we've seen the device. */
312 add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
314 /* Maybe driver failed before freeze.
315 * Restore the failed status, for debugging. */
317 add_status(dev, VIRTIO_CONFIG_S_FAILED);
322 /* We have a driver! */
323 add_status(dev, VIRTIO_CONFIG_S_DRIVER);
325 dev->config->finalize_features(dev);
328 int ret = drv->restore(dev);
330 add_status(dev, VIRTIO_CONFIG_S_FAILED);
335 /* Finally, tell the device we're all set */
336 add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
338 virtio_config_enable(dev);
342 EXPORT_SYMBOL_GPL(virtio_device_restore);
345 static int virtio_init(void)
347 if (bus_register(&virtio_bus) != 0)
348 panic("virtio bus registration failed");
352 static void __exit virtio_exit(void)
354 bus_unregister(&virtio_bus);
356 core_initcall(virtio_init);
357 module_exit(virtio_exit);
359 MODULE_LICENSE("GPL");