diff options
Diffstat (limited to 'drivers/virtio/virtio.c')
| -rw-r--r-- | drivers/virtio/virtio.c | 348 |
1 files changed, 348 insertions, 0 deletions
diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c new file mode 100644 index 0000000000..c4854e7d11 --- /dev/null +++ b/drivers/virtio/virtio.c @@ -0,0 +1,348 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include <common.h> +#include <linux/virtio.h> +#include <linux/spinlock.h> +#include <linux/virtio_config.h> +#include <module.h> +#include <linux/kernel.h> +#include <uapi/linux/virtio_ids.h> + +static int status_show(struct param_d *param, void *_dev) +{ + struct virtio_device *dev = _dev; + + dev->status_param = dev->config->get_status(dev); + return 0; +} + +static struct param_d *virtio_dev_add_param_features(struct virtio_device *dev) +{ + struct param_d *param; + unsigned int i; + char *buf; + int len = 0; + + buf = xmalloc(sizeof(dev->features)*8 + 1); + + /* We actually represent this as a bitstring, as it could be + * arbitrary length in future. */ + for (i = 0; i < sizeof(dev->features)*8; i++) + len += sprintf(buf+len, "%c", + __virtio_test_bit(dev, i) ? '1' : '0'); + + param = dev_add_param_string_fixed(&dev->dev, "features", buf); + free(buf); + + return param; +} + +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 driver *_dr) +{ + unsigned int i; + struct virtio_device *dev = dev_to_virtio(_dv); + const struct virtio_device_id *ids; + + ids = drv_to_virtio(_dr)->id_table; + for (i = 0; ids[i].device; i++) + if (virtio_id_match(dev, &ids[i])) + return 0; + + return -1; +} + +void virtio_check_driver_offered_feature(const struct virtio_device *vdev, + unsigned int fbit) +{ + unsigned int i; + struct virtio_driver *drv = drv_to_virtio(vdev->dev.driver); + + for (i = 0; i < drv->feature_table_size; i++) + if (drv->feature_table[i] == fbit) + return; + + if (drv->feature_table_legacy) { + for (i = 0; i < drv->feature_table_size_legacy; i++) + if (drv->feature_table_legacy[i] == fbit) + return; + } + + BUG(); +} +EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature); + +static void __virtio_config_changed(struct virtio_device *dev) +{ + struct virtio_driver *drv = drv_to_virtio(dev->dev.driver); + + if (!dev->config_enabled) + dev->config_change_pending = true; + else if (drv && drv->config_changed) + drv->config_changed(dev); +} + +void virtio_config_changed(struct virtio_device *dev) +{ + unsigned long flags; + + spin_lock_irqsave(&dev->config_lock, flags); + __virtio_config_changed(dev); + spin_unlock_irqrestore(&dev->config_lock, flags); +} +EXPORT_SYMBOL_GPL(virtio_config_changed); + +void virtio_config_disable(struct virtio_device *dev) +{ + dev->config_enabled = false; +} +EXPORT_SYMBOL_GPL(virtio_config_disable); + +void virtio_config_enable(struct virtio_device *dev) +{ + dev->config_enabled = true; + if (dev->config_change_pending) + __virtio_config_changed(dev); + dev->config_change_pending = false; +} +EXPORT_SYMBOL_GPL(virtio_config_enable); + +void virtio_add_status(struct virtio_device *dev, unsigned int status) +{ + dev->config->set_status(dev, dev->config->get_status(dev) | status); +} +EXPORT_SYMBOL_GPL(virtio_add_status); + +int virtio_finalize_features(struct virtio_device *dev) +{ + int ret = dev->config->finalize_features(dev); + unsigned status; + + if (ret) + return ret; + + ret = arch_has_restricted_virtio_memory_access(); + if (ret) { + if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) { + dev_warn(&dev->dev, + "device must provide VIRTIO_F_VERSION_1\n"); + return -ENODEV; + } + + if (!virtio_has_feature(dev, VIRTIO_F_ACCESS_PLATFORM)) { + dev_warn(&dev->dev, + "device must provide VIRTIO_F_ACCESS_PLATFORM\n"); + return -ENODEV; + } + } + + if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) + return 0; + + virtio_add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK); + status = dev->config->get_status(dev); + if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) { + dev_err(&dev->dev, "virtio: device refuses features: %x\n", + status); + return -ENODEV; + } + return 0; +} +EXPORT_SYMBOL_GPL(virtio_finalize_features); + +int virtio_find_vqs(struct virtio_device *vdev, unsigned int nvqs, + struct virtqueue *vqs[]) +{ + return vdev->config->find_vqs(vdev, nvqs, vqs); +} +EXPORT_SYMBOL_GPL(virtio_find_vqs); + +static int virtio_dev_probe(struct device *_d) +{ + int err, i; + struct virtio_device *dev = dev_to_virtio(_d); + struct virtio_driver *drv = drv_to_virtio(dev->dev.driver); + u64 device_features; + u64 driver_features; + u64 driver_features_legacy; + + /* We have a driver! */ + virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER); + + /* Figure out what features the device supports. */ + device_features = dev->config->get_features(dev); + + /* Figure out what features the driver supports. */ + driver_features = 0; + for (i = 0; i < drv->feature_table_size; i++) { + unsigned int f = drv->feature_table[i]; + BUG_ON(f >= 64); + driver_features |= (1ULL << f); + } + + /* Some drivers have a separate feature table for virtio v1.0 */ + if (drv->feature_table_legacy) { + driver_features_legacy = 0; + for (i = 0; i < drv->feature_table_size_legacy; i++) { + unsigned int f = drv->feature_table_legacy[i]; + BUG_ON(f >= 64); + driver_features_legacy |= (1ULL << f); + } + } else { + driver_features_legacy = driver_features; + } + + if (device_features & (1ULL << VIRTIO_F_VERSION_1)) + dev->features = driver_features & device_features; + else + dev->features = driver_features_legacy & device_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 & (1ULL << i)) + __virtio_set_bit(dev, i); + + if (drv->validate) { + err = drv->validate(dev); + if (err) + goto err; + } + + err = virtio_finalize_features(dev); + if (err) + goto err; + + err = drv->probe(dev); + if (err) + goto err; + + /* If probe didn't do it, mark device DRIVER_OK ourselves. */ + if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK)) + virtio_device_ready(dev); + + if (drv->scan) + drv->scan(dev); + + virtio_config_enable(dev); + + return 0; +err: + virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED); + return err; + +} + +static void virtio_dev_remove(struct device *_d) +{ + struct virtio_device *dev = dev_to_virtio(_d); + struct virtio_driver *drv = drv_to_virtio(dev->dev.driver); + + virtio_config_disable(dev); + + drv->remove(dev); + + WARN_ONCE(dev->config->get_status(dev), "Driver should have reset device"); + + /* Acknowledge the device's existence again. */ + virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE); +} + +static struct bus_type virtio_bus = { + .name = "virtio", + .match = virtio_dev_match, + .probe = virtio_dev_probe, + .remove = virtio_dev_remove, +}; + +int virtio_driver_register(struct virtio_driver *driver) +{ + /* Catch this early. */ + BUG_ON(driver->feature_table_size && !driver->feature_table); + driver->driver.bus = &virtio_bus; + + return register_driver(&driver->driver); +} +EXPORT_SYMBOL_GPL(virtio_driver_register); + +/** + * register_virtio_device - register virtio device + * @dev : virtio device to be registered + * + * On error, the caller must call put_device on &@dev->dev (and not kfree), + * as another code path may have obtained a reference to @dev. + * + * Returns: 0 on suceess, -error on failure + */ +int register_virtio_device(struct virtio_device *dev) +{ + int err; + + dev->dev.bus = &virtio_bus; + dev->dev.id = DEVICE_ID_DYNAMIC; + dev->dev.name = "virtio"; + dev->dev.device_node = dev_of_node(dev->dev.parent); + + spin_lock_init(&dev->config_lock); + dev->config_enabled = false; + dev->config_change_pending = false; + + /* 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. */ + virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE); + + INIT_LIST_HEAD(&dev->vqs); + + /* + * register_device() causes the bus infrastructure to look for a matching + * driver. + */ + err = register_device(&dev->dev); + if (err) + goto out; + + dev_add_param_uint32_ro(&dev->dev, "device", &dev->id.device, "0x%04x"); + dev_add_param_uint32_ro(&dev->dev, "vendor", &dev->id.vendor, "0x%04x"); + dev_add_param_uint32(&dev->dev, "status", param_set_readonly, + status_show, &dev->status_param, "0x%08x", dev); + virtio_dev_add_param_features(dev); + +out: + if (err) + virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED); + return err; +} +EXPORT_SYMBOL_GPL(register_virtio_device); + +bool is_virtio_device(struct device *dev) +{ + return dev->bus == &virtio_bus; +} +EXPORT_SYMBOL_GPL(is_virtio_device); + +void unregister_virtio_device(struct virtio_device *dev) +{ + unregister_device(&dev->dev); +} +EXPORT_SYMBOL_GPL(unregister_virtio_device); + +static int virtio_init(void) +{ + if (bus_register(&virtio_bus) != 0) + panic("virtio bus registration failed"); + return 0; +} +core_initcall(virtio_init); + +MODULE_LICENSE("GPL"); |