1 #include <linux/virtio.h> 2 #include <linux/spinlock.h> 3 #include <linux/virtio_config.h> 4 #include <linux/module.h> 5 6 /* Unique numbering for virtio devices. */ 7 static unsigned int dev_index; 8 9 static ssize_t device_show(struct device *_d, 10 struct device_attribute *attr, char *buf) 11 { 12 struct virtio_device *dev = container_of(_d,struct virtio_device,dev); 13 return sprintf(buf, "0x%04x\n", dev->id.device); 14 } 15 static ssize_t vendor_show(struct device *_d, 16 struct device_attribute *attr, char *buf) 17 { 18 struct virtio_device *dev = container_of(_d,struct virtio_device,dev); 19 return sprintf(buf, "0x%04x\n", dev->id.vendor); 20 } 21 static ssize_t status_show(struct device *_d, 22 struct device_attribute *attr, char *buf) 23 { 24 struct virtio_device *dev = container_of(_d,struct virtio_device,dev); 25 return sprintf(buf, "0x%08x\n", dev->config->get_status(dev)); 26 } 27 static ssize_t modalias_show(struct device *_d, 28 struct device_attribute *attr, char *buf) 29 { 30 struct virtio_device *dev = container_of(_d,struct virtio_device,dev); 31 32 return sprintf(buf, "virtio:d%08Xv%08X\n", 33 dev->id.device, dev->id.vendor); 34 } 35 static ssize_t features_show(struct device *_d, 36 struct device_attribute *attr, char *buf) 37 { 38 struct virtio_device *dev = container_of(_d, struct virtio_device, dev); 39 unsigned int i; 40 ssize_t len = 0; 41 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"); 48 return len; 49 } 50 static struct device_attribute virtio_dev_attrs[] = { 51 __ATTR_RO(device), 52 __ATTR_RO(vendor), 53 __ATTR_RO(status), 54 __ATTR_RO(modalias), 55 __ATTR_RO(features), 56 __ATTR_NULL 57 }; 58 59 static inline int virtio_id_match(const struct virtio_device *dev, 60 const struct virtio_device_id *id) 61 { 62 if (id->device != dev->id.device && id->device != VIRTIO_DEV_ANY_ID) 63 return 0; 64 65 return id->vendor == VIRTIO_DEV_ANY_ID || id->vendor == dev->id.vendor; 66 } 67 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) 71 { 72 unsigned int i; 73 struct virtio_device *dev = container_of(_dv,struct virtio_device,dev); 74 const struct virtio_device_id *ids; 75 76 ids = container_of(_dr, struct virtio_driver, driver)->id_table; 77 for (i = 0; ids[i].device; i++) 78 if (virtio_id_match(dev, &ids[i])) 79 return 1; 80 return 0; 81 } 82 83 static int virtio_uevent(struct device *_dv, struct kobj_uevent_env *env) 84 { 85 struct virtio_device *dev = container_of(_dv,struct virtio_device,dev); 86 87 return add_uevent_var(env, "MODALIAS=virtio:d%08Xv%08X", 88 dev->id.device, dev->id.vendor); 89 } 90 91 static void add_status(struct virtio_device *dev, unsigned status) 92 { 93 dev->config->set_status(dev, dev->config->get_status(dev) | status); 94 } 95 96 void virtio_check_driver_offered_feature(const struct virtio_device *vdev, 97 unsigned int fbit) 98 { 99 unsigned int i; 100 struct virtio_driver *drv = container_of(vdev->dev.driver, 101 struct virtio_driver, driver); 102 103 for (i = 0; i < drv->feature_table_size; i++) 104 if (drv->feature_table[i] == fbit) 105 return; 106 BUG(); 107 } 108 EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature); 109 110 static int virtio_dev_probe(struct device *_d) 111 { 112 int err, i; 113 struct virtio_device *dev = container_of(_d,struct virtio_device,dev); 114 struct virtio_driver *drv = container_of(dev->dev.driver, 115 struct virtio_driver, driver); 116 u32 device_features; 117 118 /* We have a driver! */ 119 add_status(dev, VIRTIO_CONFIG_S_DRIVER); 120 121 /* Figure out what features the device supports. */ 122 device_features = dev->config->get_features(dev); 123 124 /* Features supported by both device and driver into dev->features. */ 125 memset(dev->features, 0, sizeof(dev->features)); 126 for (i = 0; i < drv->feature_table_size; i++) { 127 unsigned int f = drv->feature_table[i]; 128 BUG_ON(f >= 32); 129 if (device_features & (1 << f)) 130 set_bit(f, dev->features); 131 } 132 133 /* Transport features always preserved to pass to finalize_features. */ 134 for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++) 135 if (device_features & (1 << i)) 136 set_bit(i, dev->features); 137 138 dev->config->finalize_features(dev); 139 140 err = drv->probe(dev); 141 if (err) 142 add_status(dev, VIRTIO_CONFIG_S_FAILED); 143 else 144 add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK); 145 146 return err; 147 } 148 149 static int virtio_dev_remove(struct device *_d) 150 { 151 struct virtio_device *dev = container_of(_d,struct virtio_device,dev); 152 struct virtio_driver *drv = container_of(dev->dev.driver, 153 struct virtio_driver, driver); 154 155 drv->remove(dev); 156 157 /* Driver should have reset device. */ 158 BUG_ON(dev->config->get_status(dev)); 159 160 /* Acknowledge the device's existence again. */ 161 add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE); 162 return 0; 163 } 164 165 static struct bus_type virtio_bus = { 166 .name = "virtio", 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, 172 }; 173 174 int register_virtio_driver(struct virtio_driver *driver) 175 { 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); 180 } 181 EXPORT_SYMBOL_GPL(register_virtio_driver); 182 183 void unregister_virtio_driver(struct virtio_driver *driver) 184 { 185 driver_unregister(&driver->driver); 186 } 187 EXPORT_SYMBOL_GPL(unregister_virtio_driver); 188 189 int register_virtio_device(struct virtio_device *dev) 190 { 191 int err; 192 193 dev->dev.bus = &virtio_bus; 194 195 /* Assign a unique device index and hence name. */ 196 dev->index = dev_index++; 197 dev_set_name(&dev->dev, "virtio%u", dev->index); 198 199 /* We always start by resetting the device, in case a previous 200 * driver messed it up. This also tests that code path a little. */ 201 dev->config->reset(dev); 202 203 /* Acknowledge that we've seen the device. */ 204 add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE); 205 206 INIT_LIST_HEAD(&dev->vqs); 207 208 /* device_register() causes the bus infrastructure to look for a 209 * matching driver. */ 210 err = device_register(&dev->dev); 211 if (err) 212 add_status(dev, VIRTIO_CONFIG_S_FAILED); 213 return err; 214 } 215 EXPORT_SYMBOL_GPL(register_virtio_device); 216 217 void unregister_virtio_device(struct virtio_device *dev) 218 { 219 device_unregister(&dev->dev); 220 } 221 EXPORT_SYMBOL_GPL(unregister_virtio_device); 222 223 static int virtio_init(void) 224 { 225 if (bus_register(&virtio_bus) != 0) 226 panic("virtio bus registration failed"); 227 return 0; 228 } 229 230 static void __exit virtio_exit(void) 231 { 232 bus_unregister(&virtio_bus); 233 } 234 core_initcall(virtio_init); 235 module_exit(virtio_exit); 236 237 MODULE_LICENSE("GPL"); 238