#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");