1 #include <linux/virtio.h> 2 #include <linux/spinlock.h> 3 #include <linux/virtio_config.h> 4 5 /* Unique numbering for virtio devices. */ 6 static unsigned int dev_index; 7 8 static ssize_t device_show(struct device *_d, 9 struct device_attribute *attr, char *buf) 10 { 11 struct virtio_device *dev = container_of(_d,struct virtio_device,dev); 12 return sprintf(buf, "%hu", dev->id.device); 13 } 14 static ssize_t vendor_show(struct device *_d, 15 struct device_attribute *attr, char *buf) 16 { 17 struct virtio_device *dev = container_of(_d,struct virtio_device,dev); 18 return sprintf(buf, "%hu", dev->id.vendor); 19 } 20 static ssize_t status_show(struct device *_d, 21 struct device_attribute *attr, char *buf) 22 { 23 struct virtio_device *dev = container_of(_d,struct virtio_device,dev); 24 return sprintf(buf, "0x%08x", dev->config->get_status(dev)); 25 } 26 static ssize_t modalias_show(struct device *_d, 27 struct device_attribute *attr, char *buf) 28 { 29 struct virtio_device *dev = container_of(_d,struct virtio_device,dev); 30 31 return sprintf(buf, "virtio:d%08Xv%08X\n", 32 dev->id.device, dev->id.vendor); 33 } 34 static ssize_t features_show(struct device *_d, 35 struct device_attribute *attr, char *buf) 36 { 37 struct virtio_device *dev = container_of(_d, struct virtio_device, dev); 38 unsigned int i; 39 ssize_t len = 0; 40 41 /* We actually represent this as a bitstring, as it could be 42 * arbitrary length in future. */ 43 for (i = 0; i < ARRAY_SIZE(dev->features)*BITS_PER_LONG; i++) 44 len += sprintf(buf+len, "%c", 45 test_bit(i, dev->features) ? '1' : '0'); 46 len += sprintf(buf+len, "\n"); 47 return len; 48 } 49 static struct device_attribute virtio_dev_attrs[] = { 50 __ATTR_RO(device), 51 __ATTR_RO(vendor), 52 __ATTR_RO(status), 53 __ATTR_RO(modalias), 54 __ATTR_RO(features), 55 __ATTR_NULL 56 }; 57 58 static inline int virtio_id_match(const struct virtio_device *dev, 59 const struct virtio_device_id *id) 60 { 61 if (id->device != dev->id.device && id->device != VIRTIO_DEV_ANY_ID) 62 return 0; 63 64 return id->vendor == VIRTIO_DEV_ANY_ID || id->vendor == dev->id.vendor; 65 } 66 67 /* This looks through all the IDs a driver claims to support. If any of them 68 * match, we return 1 and the kernel will call virtio_dev_probe(). */ 69 static int virtio_dev_match(struct device *_dv, struct device_driver *_dr) 70 { 71 unsigned int i; 72 struct virtio_device *dev = container_of(_dv,struct virtio_device,dev); 73 const struct virtio_device_id *ids; 74 75 ids = container_of(_dr, struct virtio_driver, driver)->id_table; 76 for (i = 0; ids[i].device; i++) 77 if (virtio_id_match(dev, &ids[i])) 78 return 1; 79 return 0; 80 } 81 82 static int virtio_uevent(struct device *_dv, struct kobj_uevent_env *env) 83 { 84 struct virtio_device *dev = container_of(_dv,struct virtio_device,dev); 85 86 return add_uevent_var(env, "MODALIAS=virtio:d%08Xv%08X", 87 dev->id.device, dev->id.vendor); 88 } 89 90 static void add_status(struct virtio_device *dev, unsigned status) 91 { 92 dev->config->set_status(dev, dev->config->get_status(dev) | status); 93 } 94 95 void virtio_check_driver_offered_feature(const struct virtio_device *vdev, 96 unsigned int fbit) 97 { 98 unsigned int i; 99 struct virtio_driver *drv = container_of(vdev->dev.driver, 100 struct virtio_driver, driver); 101 102 for (i = 0; i < drv->feature_table_size; i++) 103 if (drv->feature_table[i] == fbit) 104 return; 105 BUG(); 106 } 107 EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature); 108 109 static int virtio_dev_probe(struct device *_d) 110 { 111 int err, i; 112 struct virtio_device *dev = container_of(_d,struct virtio_device,dev); 113 struct virtio_driver *drv = container_of(dev->dev.driver, 114 struct virtio_driver, driver); 115 u32 device_features; 116 117 /* We have a driver! */ 118 add_status(dev, VIRTIO_CONFIG_S_DRIVER); 119 120 /* Figure out what features the device supports. */ 121 device_features = dev->config->get_features(dev); 122 123 /* Features supported by both device and driver into dev->features. */ 124 memset(dev->features, 0, sizeof(dev->features)); 125 for (i = 0; i < drv->feature_table_size; i++) { 126 unsigned int f = drv->feature_table[i]; 127 BUG_ON(f >= 32); 128 if (device_features & (1 << f)) 129 set_bit(f, dev->features); 130 } 131 132 /* Transport features always preserved to pass to finalize_features. */ 133 for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++) 134 if (device_features & (1 << i)) 135 set_bit(i, dev->features); 136 137 dev->config->finalize_features(dev); 138 139 err = drv->probe(dev); 140 if (err) 141 add_status(dev, VIRTIO_CONFIG_S_FAILED); 142 else 143 add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK); 144 145 return err; 146 } 147 148 static int virtio_dev_remove(struct device *_d) 149 { 150 struct virtio_device *dev = container_of(_d,struct virtio_device,dev); 151 struct virtio_driver *drv = container_of(dev->dev.driver, 152 struct virtio_driver, driver); 153 154 drv->remove(dev); 155 156 /* Driver should have reset device. */ 157 BUG_ON(dev->config->get_status(dev)); 158 159 /* Acknowledge the device's existence again. */ 160 add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE); 161 return 0; 162 } 163 164 static struct bus_type virtio_bus = { 165 .name = "virtio", 166 .match = virtio_dev_match, 167 .dev_attrs = virtio_dev_attrs, 168 .uevent = virtio_uevent, 169 .probe = virtio_dev_probe, 170 .remove = virtio_dev_remove, 171 }; 172 173 int register_virtio_driver(struct virtio_driver *driver) 174 { 175 /* Catch this early. */ 176 BUG_ON(driver->feature_table_size && !driver->feature_table); 177 driver->driver.bus = &virtio_bus; 178 return driver_register(&driver->driver); 179 } 180 EXPORT_SYMBOL_GPL(register_virtio_driver); 181 182 void unregister_virtio_driver(struct virtio_driver *driver) 183 { 184 driver_unregister(&driver->driver); 185 } 186 EXPORT_SYMBOL_GPL(unregister_virtio_driver); 187 188 int register_virtio_device(struct virtio_device *dev) 189 { 190 int err; 191 192 dev->dev.bus = &virtio_bus; 193 194 /* Assign a unique device index and hence name. */ 195 dev->index = dev_index++; 196 dev_set_name(&dev->dev, "virtio%u", dev->index); 197 198 /* We always start by resetting the device, in case a previous 199 * driver messed it up. This also tests that code path a little. */ 200 dev->config->reset(dev); 201 202 /* Acknowledge that we've seen the device. */ 203 add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE); 204 205 INIT_LIST_HEAD(&dev->vqs); 206 207 /* device_register() causes the bus infrastructure to look for a 208 * matching driver. */ 209 err = device_register(&dev->dev); 210 if (err) 211 add_status(dev, VIRTIO_CONFIG_S_FAILED); 212 return err; 213 } 214 EXPORT_SYMBOL_GPL(register_virtio_device); 215 216 void unregister_virtio_device(struct virtio_device *dev) 217 { 218 device_unregister(&dev->dev); 219 } 220 EXPORT_SYMBOL_GPL(unregister_virtio_device); 221 222 static int virtio_init(void) 223 { 224 if (bus_register(&virtio_bus) != 0) 225 panic("virtio bus registration failed"); 226 return 0; 227 } 228 229 static void __exit virtio_exit(void) 230 { 231 bus_unregister(&virtio_bus); 232 } 233 core_initcall(virtio_init); 234 module_exit(virtio_exit); 235 236 MODULE_LICENSE("GPL"); 237