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 < sizeof(dev->features)*8; i++)
53 len += sprintf(buf+len, "%c",
54 __virtio_test_bit(dev, i) ? '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);
165 /* We have a driver! */
166 add_status(dev, VIRTIO_CONFIG_S_DRIVER);
168 /* Figure out what features the device supports. */
169 device_features = dev->config->get_features(dev);
171 /* Features supported by both device and driver into dev->features. */
173 for (i = 0; i < drv->feature_table_size; i++) {
174 unsigned int f = drv->feature_table[i];
176 if (device_features & (1ULL << f))
177 __virtio_set_bit(dev, f);
180 /* Transport features always preserved to pass to finalize_features. */
181 for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
182 if (device_features & (1ULL << i))
183 __virtio_set_bit(dev, i);
185 dev->config->finalize_features(dev);
187 if (virtio_has_feature(dev, VIRTIO_F_VERSION_1)) {
188 add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK);
189 status = dev->config->get_status(dev);
190 if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) {
191 dev_err(_d, "virtio: device refuses features: %x\n",
198 err = drv->probe(dev);
202 add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
206 virtio_config_enable(dev);
210 add_status(dev, VIRTIO_CONFIG_S_FAILED);
215 static int virtio_dev_remove(struct device *_d)
217 struct virtio_device *dev = dev_to_virtio(_d);
218 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
220 virtio_config_disable(dev);
224 /* Driver should have reset device. */
225 WARN_ON_ONCE(dev->config->get_status(dev));
227 /* Acknowledge the device's existence again. */
228 add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
232 static struct bus_type virtio_bus = {
234 .match = virtio_dev_match,
235 .dev_groups = virtio_dev_groups,
236 .uevent = virtio_uevent,
237 .probe = virtio_dev_probe,
238 .remove = virtio_dev_remove,
241 int register_virtio_driver(struct virtio_driver *driver)
243 /* Catch this early. */
244 BUG_ON(driver->feature_table_size && !driver->feature_table);
245 driver->driver.bus = &virtio_bus;
246 return driver_register(&driver->driver);
248 EXPORT_SYMBOL_GPL(register_virtio_driver);
250 void unregister_virtio_driver(struct virtio_driver *driver)
252 driver_unregister(&driver->driver);
254 EXPORT_SYMBOL_GPL(unregister_virtio_driver);
256 int register_virtio_device(struct virtio_device *dev)
260 dev->dev.bus = &virtio_bus;
262 /* Assign a unique device index and hence name. */
263 err = ida_simple_get(&virtio_index_ida, 0, 0, GFP_KERNEL);
268 dev_set_name(&dev->dev, "virtio%u", dev->index);
270 spin_lock_init(&dev->config_lock);
271 dev->config_enabled = false;
272 dev->config_change_pending = false;
274 /* We always start by resetting the device, in case a previous
275 * driver messed it up. This also tests that code path a little. */
276 dev->config->reset(dev);
278 /* Acknowledge that we've seen the device. */
279 add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
281 INIT_LIST_HEAD(&dev->vqs);
283 /* device_register() causes the bus infrastructure to look for a
284 * matching driver. */
285 err = device_register(&dev->dev);
288 add_status(dev, VIRTIO_CONFIG_S_FAILED);
291 EXPORT_SYMBOL_GPL(register_virtio_device);
293 void unregister_virtio_device(struct virtio_device *dev)
295 int index = dev->index; /* save for after device release */
297 device_unregister(&dev->dev);
298 ida_simple_remove(&virtio_index_ida, index);
300 EXPORT_SYMBOL_GPL(unregister_virtio_device);
302 #ifdef CONFIG_PM_SLEEP
303 int virtio_device_freeze(struct virtio_device *dev)
305 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
307 virtio_config_disable(dev);
309 dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED;
311 if (drv && drv->freeze)
312 return drv->freeze(dev);
316 EXPORT_SYMBOL_GPL(virtio_device_freeze);
318 int virtio_device_restore(struct virtio_device *dev)
320 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
322 /* We always start by resetting the device, in case a previous
323 * driver messed it up. */
324 dev->config->reset(dev);
326 /* Acknowledge that we've seen the device. */
327 add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
329 /* Maybe driver failed before freeze.
330 * Restore the failed status, for debugging. */
332 add_status(dev, VIRTIO_CONFIG_S_FAILED);
337 /* We have a driver! */
338 add_status(dev, VIRTIO_CONFIG_S_DRIVER);
340 dev->config->finalize_features(dev);
343 int ret = drv->restore(dev);
345 add_status(dev, VIRTIO_CONFIG_S_FAILED);
350 /* Finally, tell the device we're all set */
351 add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
353 virtio_config_enable(dev);
357 EXPORT_SYMBOL_GPL(virtio_device_restore);
360 static int virtio_init(void)
362 if (bus_register(&virtio_bus) != 0)
363 panic("virtio bus registration failed");
367 static void __exit virtio_exit(void)
369 bus_unregister(&virtio_bus);
371 core_initcall(virtio_init);
372 module_exit(virtio_exit);
374 MODULE_LICENSE("GPL");