#include <linux/virtio.h>#include <linux/spinlock.h>#include <linux/virtio_config.h>#include <linux/module.h>#include <linux/idr.h> /* Unique numbering for virtio devices. */static DEFINE_IDA(virtio_index_ida); static ssize_t device_show(struct device *_d,			   struct device_attribute *attr, char *buf){	struct virtio_device *dev = container_of(_d,struct virtio_device,dev);	return sprintf(buf, "0x%04x\n", dev->id.device);}static ssize_t vendor_show(struct device *_d,			   struct device_attribute *attr, char *buf){	struct virtio_device *dev = container_of(_d,struct virtio_device,dev);	return sprintf(buf, "0x%04x\n", dev->id.vendor);}static ssize_t status_show(struct device *_d,			   struct device_attribute *attr, char *buf){	struct virtio_device *dev = container_of(_d,struct virtio_device,dev);	return sprintf(buf, "0x%08x\n", dev->config->get_status(dev));}static ssize_t modalias_show(struct device *_d,			     struct device_attribute *attr, char *buf){	struct virtio_device *dev = container_of(_d,struct virtio_device,dev); 	return sprintf(buf, "virtio:d%08Xv%08X\n",		       dev->id.device, dev->id.vendor);}static ssize_t features_show(struct device *_d,			     struct device_attribute *attr, char *buf){	struct virtio_device *dev = container_of(_d, struct virtio_device, dev);	unsigned int i;	ssize_t len = 0; 	/* We actually represent this as a bitstring, as it could be	 * arbitrary length in future. */	for (i = 0; i < ARRAY_SIZE(dev->features)*BITS_PER_LONG; i++)		len += sprintf(buf+len, "%c",			       test_bit(i, dev->features) ? '1' : '0');	len += sprintf(buf+len, "\n");	return len;}static struct device_attribute virtio_dev_attrs[] = {	__ATTR_RO(device),	__ATTR_RO(vendor),	__ATTR_RO(status),	__ATTR_RO(modalias),	__ATTR_RO(features),	__ATTR_NULL}; static inline int virtio_id_match(const struct virtio_device *dev,				  const struct virtio_device_id *id){	if (id->device != dev->id.device && id->device != VIRTIO_DEV_ANY_ID)		return 0; 	return id->vendor == VIRTIO_DEV_ANY_ID || id->vendor == dev->id.vendor;} /* This looks through all the IDs a driver claims to support.  If any of them * match, we return 1 and the kernel will call virtio_dev_probe(). */static int virtio_dev_match(struct device *_dv, struct device_driver *_dr){	unsigned int i;	struct virtio_device *dev = container_of(_dv,struct virtio_device,dev);	const struct virtio_device_id *ids; 	ids = container_of(_dr, struct virtio_driver, driver)->id_table;	for (i = 0; ids[i].device; i++)		if (virtio_id_match(dev, &ids[i]))			return 1;	return 0;} static int virtio_uevent(struct device *_dv, struct kobj_uevent_env *env){	struct virtio_device *dev = container_of(_dv,struct virtio_device,dev); 	return add_uevent_var(env, "MODALIAS=virtio:d%08Xv%08X",			      dev->id.device, dev->id.vendor);} static void add_status(struct virtio_device *dev, unsigned status){	dev->config->set_status(dev, dev->config->get_status(dev) | status);} void virtio_check_driver_offered_feature(const struct virtio_device *vdev,					 unsigned int fbit){	unsigned int i;	struct virtio_driver *drv = container_of(vdev->dev.driver,						 struct virtio_driver, driver); 	for (i = 0; i < drv->feature_table_size; i++)		if (drv->feature_table[i] == fbit)			return;	BUG();}EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature); static int virtio_dev_probe(struct device *_d){	int err, i;	struct virtio_device *dev = container_of(_d,struct virtio_device,dev);	struct virtio_driver *drv = container_of(dev->dev.driver,						 struct virtio_driver, driver);	u32 device_features; 	/* We have a driver! */	add_status(dev, VIRTIO_CONFIG_S_DRIVER); 	/* Figure out what features the device supports. */	device_features = dev->config->get_features(dev); 	/* Features supported by both device and driver into dev->features. */	memset(dev->features, 0, sizeof(dev->features));	for (i = 0; i < drv->feature_table_size; i++) {		unsigned int f = drv->feature_table[i];		BUG_ON(f >= 32);		if (device_features & (1 << f))			set_bit(f, dev->features);	} 	/* Transport features always preserved to pass to finalize_features. */	for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)		if (device_features & (1 << i))			set_bit(i, dev->features); 	dev->config->finalize_features(dev); 	err = drv->probe(dev);	if (err)		add_status(dev, VIRTIO_CONFIG_S_FAILED);	else		add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK); 	return err;} static int virtio_dev_remove(struct device *_d){	struct virtio_device *dev = container_of(_d,struct virtio_device,dev);	struct virtio_driver *drv = container_of(dev->dev.driver,						 struct virtio_driver, driver); 	drv->remove(dev); 	/* Driver should have reset device. */	BUG_ON(dev->config->get_status(dev)); 	/* Acknowledge the device's existence again. */	add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);	return 0;} static struct bus_type virtio_bus = {	.name  = "virtio",	.match = virtio_dev_match,	.dev_attrs = virtio_dev_attrs,	.uevent = virtio_uevent,	.probe = virtio_dev_probe,	.remove = virtio_dev_remove,}; int register_virtio_driver(struct virtio_driver *driver){	/* Catch this early. */	BUG_ON(driver->feature_table_size && !driver->feature_table);	driver->driver.bus = &virtio_bus;	return driver_register(&driver->driver);}EXPORT_SYMBOL_GPL(register_virtio_driver); void unregister_virtio_driver(struct virtio_driver *driver){	driver_unregister(&driver->driver);}EXPORT_SYMBOL_GPL(unregister_virtio_driver); int register_virtio_device(struct virtio_device *dev){	int err; 	dev->dev.bus = &virtio_bus; 	/* Assign a unique device index and hence name. */	err = ida_simple_get(&virtio_index_ida, 0, 0, GFP_KERNEL);	if (err < 0)		goto out; 	dev->index = err;	dev_set_name(&dev->dev, "virtio%u", dev->index); 	/* We always start by resetting the device, in case a previous	 * driver messed it up.  This also tests that code path a little. */	dev->config->reset(dev); 	/* Acknowledge that we've seen the device. */	add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE); 	INIT_LIST_HEAD(&dev->vqs); 	/* device_register() causes the bus infrastructure to look for a	 * matching driver. */	err = device_register(&dev->dev);out:	if (err)		add_status(dev, VIRTIO_CONFIG_S_FAILED);	return err;}EXPORT_SYMBOL_GPL(register_virtio_device); void unregister_virtio_device(struct virtio_device *dev){	device_unregister(&dev->dev);	ida_simple_remove(&virtio_index_ida, dev->index);}EXPORT_SYMBOL_GPL(unregister_virtio_device); static int virtio_init(void){	if (bus_register(&virtio_bus) != 0)		panic("virtio bus registration failed");	return 0;} static void __exit virtio_exit(void){	bus_unregister(&virtio_bus);}core_initcall(virtio_init);module_exit(virtio_exit); MODULE_LICENSE("GPL");