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Diffstat (limited to 'include/linux/virtio_config.h')
| -rw-r--r-- | include/linux/virtio_config.h | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h new file mode 100644 index 00000000000..bcc01888df7 --- /dev/null +++ b/include/linux/virtio_config.h @@ -0,0 +1,111 @@ +#ifndef _LINUX_VIRTIO_CONFIG_H +#define _LINUX_VIRTIO_CONFIG_H +/* Virtio devices use a standardized configuration space to define their + * features and pass configuration information, but each implementation can + * store and access that space differently. */ +#include <linux/types.h> + +/* Status byte for guest to report progress, and synchronize config. */ +/* We have seen device and processed generic fields (VIRTIO_CONFIG_F_VIRTIO) */ +#define VIRTIO_CONFIG_S_ACKNOWLEDGE 1 +/* We have found a driver for the device. */ +#define VIRTIO_CONFIG_S_DRIVER 2 +/* Driver has used its parts of the config, and is happy */ +#define VIRTIO_CONFIG_S_DRIVER_OK 4 +/* We've given up on this device. */ +#define VIRTIO_CONFIG_S_FAILED 0x80 + +/* Feature byte (actually 7 bits availabe): */ +/* Requirements/features of the virtio implementation. */ +#define VIRTIO_CONFIG_F_VIRTIO 1 +/* Requirements/features of the virtqueue (may have more than one). */ +#define VIRTIO_CONFIG_F_VIRTQUEUE 2 + +#ifdef __KERNEL__ +struct virtio_device; + +/** + * virtio_config_ops - operations for configuring a virtio device + * @find: search for the next configuration field of the given type. + * vdev: the virtio_device + * type: the feature type + * len: the (returned) length of the field if found. + * Returns a token if found, or NULL. Never returnes the same field twice + * (ie. it's used up). + * @get: read the value of a configuration field after find(). + * vdev: the virtio_device + * token: the token returned from find(). + * buf: the buffer to write the field value into. + * len: the length of the buffer (given by find()). + * Note that contents are conventionally little-endian. + * @set: write the value of a configuration field after find(). + * vdev: the virtio_device + * token: the token returned from find(). + * buf: the buffer to read the field value from. + * len: the length of the buffer (given by find()). + * Note that contents are conventionally little-endian. + * @get_status: read the status byte + * vdev: the virtio_device + * Returns the status byte + * @set_status: write the status byte + * vdev: the virtio_device + * status: the new status byte + * @find_vq: find the first VIRTIO_CONFIG_F_VIRTQUEUE and create a virtqueue. + * vdev: the virtio_device + * callback: the virqtueue callback + * Returns the new virtqueue or ERR_PTR(). + * @del_vq: free a virtqueue found by find_vq(). + */ +struct virtio_config_ops +{ + void *(*find)(struct virtio_device *vdev, u8 type, unsigned *len); + void (*get)(struct virtio_device *vdev, void *token, + void *buf, unsigned len); + void (*set)(struct virtio_device *vdev, void *token, + const void *buf, unsigned len); + u8 (*get_status)(struct virtio_device *vdev); + void (*set_status)(struct virtio_device *vdev, u8 status); + struct virtqueue *(*find_vq)(struct virtio_device *vdev, + bool (*callback)(struct virtqueue *)); + void (*del_vq)(struct virtqueue *vq); +}; + +/** + * virtio_config_val - get a single virtio config and mark it used. + * @config: the virtio config space + * @type: the type to search for. + * @val: a pointer to the value to fill in. + * + * Once used, the config type is marked with VIRTIO_CONFIG_F_USED so it can't + * be found again. This version does endian conversion. */ +#define virtio_config_val(vdev, type, v) ({ \ + int _err = __virtio_config_val((vdev),(type),(v),sizeof(*(v))); \ + \ + BUILD_BUG_ON(sizeof(*(v)) != 1 && sizeof(*(v)) != 2 \ + && sizeof(*(v)) != 4 && sizeof(*(v)) != 8); \ + if (!_err) { \ + switch (sizeof(*(v))) { \ + case 2: le16_to_cpus((__u16 *) v); break; \ + case 4: le32_to_cpus((__u32 *) v); break; \ + case 8: le64_to_cpus((__u64 *) v); break; \ + } \ + } \ + _err; \ +}) + +int __virtio_config_val(struct virtio_device *dev, + u8 type, void *val, size_t size); + +/** + * virtio_use_bit - helper to use a feature bit in a bitfield value. + * @dev: the virtio device + * @token: the token as returned from vdev->config->find(). + * @len: the length of the field. + * @bitnum: the bit to test. + * + * If handed a NULL token, it returns false, otherwise returns bit status. + * If it's one, it sets the mirroring acknowledgement bit. */ +int virtio_use_bit(struct virtio_device *vdev, + void *token, unsigned int len, unsigned int bitnum); +#endif /* __KERNEL__ */ +#endif /* _LINUX_VIRTIO_CONFIG_H */ |