#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 features. */
/* 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
#ifdef __KERNEL__
#include <linux/virtio.h>
/**
* virtio_config_ops - operations for configuring a virtio device
* @feature: search for a feature in this config
* vdev: the virtio_device
* bit: the feature bit
* Returns true if the feature is supported. Acknowledges the feature
* so the host can see it.
* @get: read the value of a configuration field
* vdev: the virtio_device
* offset: the offset of the configuration field
* buf: the buffer to write the field value into.
* len: the length of the buffer
* @set: write the value of a configuration field
* vdev: the virtio_device
* offset: the offset of the configuration field
* buf: the buffer to read the field value from.
* len: the length of the buffer
* @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
* @reset: reset the device
* vdev: the virtio device
* After this, status and feature negotiation must be done again
* @find_vq: find a virtqueue and instantiate it.
* vdev: the virtio_device
* index: the 0-based virtqueue number in case there's more than one.
* callback: the virqtueue callback
* Returns the new virtqueue or ERR_PTR() (eg. -ENOENT).
* @del_vq: free a virtqueue found by find_vq().
*/
struct virtio_config_ops
{
bool (*feature)(struct virtio_device *vdev, unsigned bit);
void (*get)(struct virtio_device *vdev, unsigned offset,
void *buf, unsigned len);
void (*set)(struct virtio_device *vdev, unsigned offset,
const void *buf, unsigned len);
u8 (*get_status)(struct virtio_device *vdev);
void (*set_status)(struct virtio_device *vdev, u8 status);
void (*reset)(struct virtio_device *vdev);
struct virtqueue *(*find_vq)(struct virtio_device *vdev,
unsigned index,
void (*callback)(struct virtqueue *));
void (*del_vq)(struct virtqueue *vq);
};
/**
* virtio_config_val - look for a feature and get a virtio config entry.
* @vdev: the virtio device
* @fbit: the feature bit
* @offset: the type to search for.
* @val: a pointer to the value to fill in.
*
* The return value is -ENOENT if the feature doesn't exist. Otherwise
* the config value is copied into whatever is pointed to by v. */
#define virtio_config_val(vdev, fbit, offset, v) \
virtio_config_buf((vdev), (fbit), (offset), (v), sizeof(v))
static inline int virtio_config_buf(struct virtio_device *vdev,
unsigned int fbit,
unsigned int offset,
void *buf, unsigned len)
{
if (!vdev->config->feature(vdev, fbit))
return -ENOENT;
vdev->config->get(vdev, offset, buf, len);
return 0;
}
#endif /* __KERNEL__ */
#endif /* _LINUX_VIRTIO_CONFIG_H */
