1 #include <linux/virtio.h> 2 #include <linux/spinlock.h> 3 #include <linux/virtio_config.h> 4 #include <linux/module.h> 5 #include <linux/idr.h> 6 7 /* Unique numbering for virtio devices. */ 8 static DEFINE_IDA(virtio_index_ida); 9 10 static ssize_t device_show(struct device *_d, 11 struct device_attribute *attr, char *buf) 12 { 13 struct virtio_device *dev = dev_to_virtio(_d); 14 return sprintf(buf, "0x%04x\n", dev->id.device); 15 } 16 static DEVICE_ATTR_RO(device); 17 18 static ssize_t vendor_show(struct device *_d, 19 struct device_attribute *attr, char *buf) 20 { 21 struct virtio_device *dev = dev_to_virtio(_d); 22 return sprintf(buf, "0x%04x\n", dev->id.vendor); 23 } 24 static DEVICE_ATTR_RO(vendor); 25 26 static ssize_t status_show(struct device *_d, 27 struct device_attribute *attr, char *buf) 28 { 29 struct virtio_device *dev = dev_to_virtio(_d); 30 return sprintf(buf, "0x%08x\n", dev->config->get_status(dev)); 31 } 32 static DEVICE_ATTR_RO(status); 33 34 static ssize_t modalias_show(struct device *_d, 35 struct device_attribute *attr, char *buf) 36 { 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); 40 } 41 static DEVICE_ATTR_RO(modalias); 42 43 static ssize_t features_show(struct device *_d, 44 struct device_attribute *attr, char *buf) 45 { 46 struct virtio_device *dev = dev_to_virtio(_d); 47 unsigned int i; 48 ssize_t len = 0; 49 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"); 56 return len; 57 } 58 static DEVICE_ATTR_RO(features); 59 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, 66 NULL, 67 }; 68 ATTRIBUTE_GROUPS(virtio_dev); 69 70 static inline int virtio_id_match(const struct virtio_device *dev, 71 const struct virtio_device_id *id) 72 { 73 if (id->device != dev->id.device && id->device != VIRTIO_DEV_ANY_ID) 74 return 0; 75 76 return id->vendor == VIRTIO_DEV_ANY_ID || id->vendor == dev->id.vendor; 77 } 78 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) 82 { 83 unsigned int i; 84 struct virtio_device *dev = dev_to_virtio(_dv); 85 const struct virtio_device_id *ids; 86 87 ids = drv_to_virtio(_dr)->id_table; 88 for (i = 0; ids[i].device; i++) 89 if (virtio_id_match(dev, &ids[i])) 90 return 1; 91 return 0; 92 } 93 94 static int virtio_uevent(struct device *_dv, struct kobj_uevent_env *env) 95 { 96 struct virtio_device *dev = dev_to_virtio(_dv); 97 98 return add_uevent_var(env, "MODALIAS=virtio:d%08Xv%08X", 99 dev->id.device, dev->id.vendor); 100 } 101 102 static void add_status(struct virtio_device *dev, unsigned status) 103 { 104 dev->config->set_status(dev, dev->config->get_status(dev) | status); 105 } 106 107 void virtio_check_driver_offered_feature(const struct virtio_device *vdev, 108 unsigned int fbit) 109 { 110 unsigned int i; 111 struct virtio_driver *drv = drv_to_virtio(vdev->dev.driver); 112 113 for (i = 0; i < drv->feature_table_size; i++) 114 if (drv->feature_table[i] == fbit) 115 return; 116 BUG(); 117 } 118 EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature); 119 120 static void __virtio_config_changed(struct virtio_device *dev) 121 { 122 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver); 123 124 if (!dev->config_enabled) 125 dev->config_change_pending = true; 126 else if (drv && drv->config_changed) 127 drv->config_changed(dev); 128 } 129 130 void virtio_config_changed(struct virtio_device *dev) 131 { 132 unsigned long flags; 133 134 spin_lock_irqsave(&dev->config_lock, flags); 135 __virtio_config_changed(dev); 136 spin_unlock_irqrestore(&dev->config_lock, flags); 137 } 138 EXPORT_SYMBOL_GPL(virtio_config_changed); 139 140 static void virtio_config_disable(struct virtio_device *dev) 141 { 142 spin_lock_irq(&dev->config_lock); 143 dev->config_enabled = false; 144 spin_unlock_irq(&dev->config_lock); 145 } 146 147 static void virtio_config_enable(struct virtio_device *dev) 148 { 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); 155 } 156 157 static int virtio_dev_probe(struct device *_d) 158 { 159 int err, i; 160 struct virtio_device *dev = dev_to_virtio(_d); 161 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver); 162 u32 device_features; 163 164 /* We have a driver! */ 165 add_status(dev, VIRTIO_CONFIG_S_DRIVER); 166 167 /* Figure out what features the device supports. */ 168 device_features = dev->config->get_features(dev); 169 170 /* 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]; 174 BUG_ON(f >= 32); 175 if (device_features & (1 << f)) 176 set_bit(f, dev->features); 177 } 178 179 /* 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); 183 184 dev->config->finalize_features(dev); 185 186 err = drv->probe(dev); 187 if (err) 188 add_status(dev, VIRTIO_CONFIG_S_FAILED); 189 else { 190 add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK); 191 if (drv->scan) 192 drv->scan(dev); 193 194 virtio_config_enable(dev); 195 } 196 197 return err; 198 } 199 200 static int virtio_dev_remove(struct device *_d) 201 { 202 struct virtio_device *dev = dev_to_virtio(_d); 203 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver); 204 205 virtio_config_disable(dev); 206 207 drv->remove(dev); 208 209 /* Driver should have reset device. */ 210 WARN_ON_ONCE(dev->config->get_status(dev)); 211 212 /* Acknowledge the device's existence again. */ 213 add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE); 214 return 0; 215 } 216 217 static struct bus_type virtio_bus = { 218 .name = "virtio", 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, 224 }; 225 226 int register_virtio_driver(struct virtio_driver *driver) 227 { 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); 232 } 233 EXPORT_SYMBOL_GPL(register_virtio_driver); 234 235 void unregister_virtio_driver(struct virtio_driver *driver) 236 { 237 driver_unregister(&driver->driver); 238 } 239 EXPORT_SYMBOL_GPL(unregister_virtio_driver); 240 241 int register_virtio_device(struct virtio_device *dev) 242 { 243 int err; 244 245 dev->dev.bus = &virtio_bus; 246 247 /* Assign a unique device index and hence name. */ 248 err = ida_simple_get(&virtio_index_ida, 0, 0, GFP_KERNEL); 249 if (err < 0) 250 goto out; 251 252 dev->index = err; 253 dev_set_name(&dev->dev, "virtio%u", dev->index); 254 255 spin_lock_init(&dev->config_lock); 256 dev->config_enabled = false; 257 dev->config_change_pending = false; 258 259 /* 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); 262 263 /* Acknowledge that we've seen the device. */ 264 add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE); 265 266 INIT_LIST_HEAD(&dev->vqs); 267 268 /* device_register() causes the bus infrastructure to look for a 269 * matching driver. */ 270 err = device_register(&dev->dev); 271 out: 272 if (err) 273 add_status(dev, VIRTIO_CONFIG_S_FAILED); 274 return err; 275 } 276 EXPORT_SYMBOL_GPL(register_virtio_device); 277 278 void unregister_virtio_device(struct virtio_device *dev) 279 { 280 int index = dev->index; /* save for after device release */ 281 282 device_unregister(&dev->dev); 283 ida_simple_remove(&virtio_index_ida, index); 284 } 285 EXPORT_SYMBOL_GPL(unregister_virtio_device); 286 287 #ifdef CONFIG_PM_SLEEP 288 int virtio_device_freeze(struct virtio_device *dev) 289 { 290 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver); 291 292 virtio_config_disable(dev); 293 294 dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED; 295 296 if (drv && drv->freeze) 297 return drv->freeze(dev); 298 299 return 0; 300 } 301 EXPORT_SYMBOL_GPL(virtio_device_freeze); 302 303 int virtio_device_restore(struct virtio_device *dev) 304 { 305 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver); 306 307 /* We always start by resetting the device, in case a previous 308 * driver messed it up. */ 309 dev->config->reset(dev); 310 311 /* Acknowledge that we've seen the device. */ 312 add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE); 313 314 /* Maybe driver failed before freeze. 315 * Restore the failed status, for debugging. */ 316 if (dev->failed) 317 add_status(dev, VIRTIO_CONFIG_S_FAILED); 318 319 if (!drv) 320 return 0; 321 322 /* We have a driver! */ 323 add_status(dev, VIRTIO_CONFIG_S_DRIVER); 324 325 dev->config->finalize_features(dev); 326 327 if (drv->restore) { 328 int ret = drv->restore(dev); 329 if (ret) { 330 add_status(dev, VIRTIO_CONFIG_S_FAILED); 331 return ret; 332 } 333 } 334 335 /* Finally, tell the device we're all set */ 336 add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK); 337 338 virtio_config_enable(dev); 339 340 return 0; 341 } 342 EXPORT_SYMBOL_GPL(virtio_device_restore); 343 #endif 344 345 static int virtio_init(void) 346 { 347 if (bus_register(&virtio_bus) != 0) 348 panic("virtio bus registration failed"); 349 return 0; 350 } 351 352 static void __exit virtio_exit(void) 353 { 354 bus_unregister(&virtio_bus); 355 } 356 core_initcall(virtio_init); 357 module_exit(virtio_exit); 358 359 MODULE_LICENSE("GPL"); 360