#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 */
