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 = container_of(_d,struct virtio_device,dev); 14 return sprintf(buf, "0x%04x\n", dev->id.device); 15 } 16 static ssize_t vendor_show(struct device *_d, 17 struct device_attribute *attr, char *buf) 18 { 19 struct virtio_device *dev = container_of(_d,struct virtio_device,dev); 20 return sprintf(buf, "0x%04x\n", dev->id.vendor); 21 } 22 static ssize_t status_show(struct device *_d, 23 struct device_attribute *attr, char *buf) 24 { 25 struct virtio_device *dev = container_of(_d,struct virtio_device,dev); 26 return sprintf(buf, "0x%08x\n", dev->config->get_status(dev)); 27 } 28 static ssize_t modalias_show(struct device *_d, 29 struct device_attribute *attr, char *buf) 30 { 31 struct virtio_device *dev = container_of(_d,struct virtio_device,dev); 32 33 return sprintf(buf, "virtio:d%08Xv%08X\n", 34 dev->id.device, dev->id.vendor); 35 } 36 static ssize_t features_show(struct device *_d, 37 struct device_attribute *attr, char *buf) 38 { 39 struct virtio_device *dev = container_of(_d, struct virtio_device, dev); 40 unsigned int i; 41 ssize_t len = 0; 42 43 /* We actually represent this as a bitstring, as it could be 44 * arbitrary length in future. */ 45 for (i = 0; i < ARRAY_SIZE(dev->features)*BITS_PER_LONG; i++) 46 len += sprintf(buf+len, "%c", 47 test_bit(i, dev->features) ? '1' : '0'); 48 len += sprintf(buf+len, "\n"); 49 return len; 50 } 51 static struct device_attribute virtio_dev_attrs[] = { 52 __ATTR_RO(device), 53 __ATTR_RO(vendor), 54 __ATTR_RO(status), 55 __ATTR_RO(modalias), 56 __ATTR_RO(features), 57 __ATTR_NULL 58 }; 59 60 static inline int virtio_id_match(const struct virtio_device *dev, 61 const struct virtio_device_id *id) 62 { 63 if (id->device != dev->id.device && id->device != VIRTIO_DEV_ANY_ID) 64 return 0; 65 66 return id->vendor == VIRTIO_DEV_ANY_ID || id->vendor == dev->id.vendor; 67 } 68 69 /* This looks through all the IDs a driver claims to support. If any of them 70 * match, we return 1 and the kernel will call virtio_dev_probe(). */ 71 static int virtio_dev_match(struct device *_dv, struct device_driver *_dr) 72 { 73 unsigned int i; 74 struct virtio_device *dev = container_of(_dv,struct virtio_device,dev); 75 const struct virtio_device_id *ids; 76 77 ids = container_of(_dr, struct virtio_driver, driver)->id_table; 78 for (i = 0; ids[i].device; i++) 79 if (virtio_id_match(dev, &ids[i])) 80 return 1; 81 return 0; 82 } 83 84 static int virtio_uevent(struct device *_dv, struct kobj_uevent_env *env) 85 { 86 struct virtio_device *dev = container_of(_dv,struct virtio_device,dev); 87 88 return add_uevent_var(env, "MODALIAS=virtio:d%08Xv%08X", 89 dev->id.device, dev->id.vendor); 90 } 91 92 static void add_status(struct virtio_device *dev, unsigned status) 93 { 94 dev->config->set_status(dev, dev->config->get_status(dev) | status); 95 } 96 97 void virtio_check_driver_offered_feature(const struct virtio_device *vdev, 98 unsigned int fbit) 99 { 100 unsigned int i; 101 struct virtio_driver *drv = container_of(vdev->dev.driver, 102 struct virtio_driver, driver); 103 104 for (i = 0; i < drv->feature_table_size; i++) 105 if (drv->feature_table[i] == fbit) 106 return; 107 BUG(); 108 } 109 EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature); 110 111 static int virtio_dev_probe(struct device *_d) 112 { 113 int err, i; 114 struct virtio_device *dev = container_of(_d,struct virtio_device,dev); 115 struct virtio_driver *drv = container_of(dev->dev.driver, 116 struct virtio_driver, driver); 117 u32 device_features; 118 119 /* We have a driver! */ 120 add_status(dev, VIRTIO_CONFIG_S_DRIVER); 121 122 /* Figure out what features the device supports. */ 123 device_features = dev->config->get_features(dev); 124 125 /* Features supported by both device and driver into dev->features. */ 126 memset(dev->features, 0, sizeof(dev->features)); 127 for (i = 0; i < drv->feature_table_size; i++) { 128 unsigned int f = drv->feature_table[i]; 129 BUG_ON(f >= 32); 130 if (device_features & (1 << f)) 131 set_bit(f, dev->features); 132 } 133 134 /* Transport features always preserved to pass to finalize_features. */ 135 for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++) 136 if (device_features & (1 << i)) 137 set_bit(i, dev->features); 138 139 dev->config->finalize_features(dev); 140 141 err = drv->probe(dev); 142 if (err) 143 add_status(dev, VIRTIO_CONFIG_S_FAILED); 144 else { 145 add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK); 146 if (drv->scan) 147 drv->scan(dev); 148 } 149 150 return err; 151 } 152 153 static int virtio_dev_remove(struct device *_d) 154 { 155 struct virtio_device *dev = container_of(_d,struct virtio_device,dev); 156 struct virtio_driver *drv = container_of(dev->dev.driver, 157 struct virtio_driver, driver); 158 159 drv->remove(dev); 160 161 /* Driver should have reset device. */ 162 BUG_ON(dev->config->get_status(dev)); 163 164 /* Acknowledge the device's existence again. */ 165 add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE); 166 return 0; 167 } 168 169 static struct bus_type virtio_bus = { 170 .name = "virtio", 171 .match = virtio_dev_match, 172 .dev_attrs = virtio_dev_attrs, 173 .uevent = virtio_uevent, 174 .probe = virtio_dev_probe, 175 .remove = virtio_dev_remove, 176 }; 177 178 int register_virtio_driver(struct virtio_driver *driver) 179 { 180 /* Catch this early. */ 181 BUG_ON(driver->feature_table_size && !driver->feature_table); 182 driver->driver.bus = &virtio_bus; 183 return driver_register(&driver->driver); 184 } 185 EXPORT_SYMBOL_GPL(register_virtio_driver); 186 187 void unregister_virtio_driver(struct virtio_driver *driver) 188 { 189 driver_unregister(&driver->driver); 190 } 191 EXPORT_SYMBOL_GPL(unregister_virtio_driver); 192 193 int register_virtio_device(struct virtio_device *dev) 194 { 195 int err; 196 197 dev->dev.bus = &virtio_bus; 198 199 /* Assign a unique device index and hence name. */ 200 err = ida_simple_get(&virtio_index_ida, 0, 0, GFP_KERNEL); 201 if (err < 0) 202 goto out; 203 204 dev->index = err; 205 dev_set_name(&dev->dev, "virtio%u", dev->index); 206 207 /* We always start by resetting the device, in case a previous 208 * driver messed it up. This also tests that code path a little. */ 209 dev->config->reset(dev); 210 211 /* Acknowledge that we've seen the device. */ 212 add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE); 213 214 INIT_LIST_HEAD(&dev->vqs); 215 216 /* device_register() causes the bus infrastructure to look for a 217 * matching driver. */ 218 err = device_register(&dev->dev); 219 out: 220 if (err) 221 add_status(dev, VIRTIO_CONFIG_S_FAILED); 222 return err; 223 } 224 EXPORT_SYMBOL_GPL(register_virtio_device); 225 226 void unregister_virtio_device(struct virtio_device *dev) 227 { 228 device_unregister(&dev->dev); 229 ida_simple_remove(&virtio_index_ida, dev->index); 230 } 231 EXPORT_SYMBOL_GPL(unregister_virtio_device); 232 233 static int virtio_init(void) 234 { 235 if (bus_register(&virtio_bus) != 0) 236 panic("virtio bus registration failed"); 237 return 0; 238 } 239 240 static void __exit virtio_exit(void) 241 { 242 bus_unregister(&virtio_bus); 243 } 244 core_initcall(virtio_init); 245 module_exit(virtio_exit); 246 247 MODULE_LICENSE("GPL"); 248