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Diffstat (limited to 'include/linux/virtio.h')
| -rw-r--r-- | include/linux/virtio.h | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/include/linux/virtio.h b/include/linux/virtio.h new file mode 100644 index 00000000000..14e1379876d --- /dev/null +++ b/include/linux/virtio.h @@ -0,0 +1,110 @@ +#ifndef _LINUX_VIRTIO_H +#define _LINUX_VIRTIO_H +/* Everything a virtio driver needs to work with any particular virtio + * implementation. */ +#include <linux/types.h> +#include <linux/scatterlist.h> +#include <linux/spinlock.h> +#include <linux/device.h> +#include <linux/mod_devicetable.h> + +/** + * virtqueue - a queue to register buffers for sending or receiving. + * @callback: the function to call when buffers are consumed (can be NULL). + * If this returns false, callbacks are suppressed until vq_ops->restart + * is called. + * @vdev: the virtio device this queue was created for. + * @vq_ops: the operations for this virtqueue (see below). + * @priv: a pointer for the virtqueue implementation to use. + */ +struct virtqueue +{ + bool (*callback)(struct virtqueue *vq); + struct virtio_device *vdev; + struct virtqueue_ops *vq_ops; + void *priv; +}; + +/** + * virtqueue_ops - operations for virtqueue abstraction layer + * @add_buf: expose buffer to other end + * vq: the struct virtqueue we're talking about. + * sg: the description of the buffer(s). + * out_num: the number of sg readable by other side + * in_num: the number of sg which are writable (after readable ones) + * data: the token identifying the buffer. + * Returns 0 or an error. + * @kick: update after add_buf + * vq: the struct virtqueue + * After one or more add_buf calls, invoke this to kick the other side. + * @get_buf: get the next used buffer + * vq: the struct virtqueue we're talking about. + * len: the length written into the buffer + * Returns NULL or the "data" token handed to add_buf. + * @restart: restart callbacks after callback returned false. + * vq: the struct virtqueue we're talking about. + * This returns "false" (and doesn't re-enable) if there are pending + * buffers in the queue, to avoid a race. + * @shutdown: "unadd" all buffers. + * vq: the struct virtqueue we're talking about. + * Remove everything from the queue. + * + * Locking rules are straightforward: the driver is responsible for + * locking. No two operations may be invoked simultaneously. + * + * All operations can be called in any context. + */ +struct virtqueue_ops { + int (*add_buf)(struct virtqueue *vq, + struct scatterlist sg[], + unsigned int out_num, + unsigned int in_num, + void *data); + + void (*kick)(struct virtqueue *vq); + + void *(*get_buf)(struct virtqueue *vq, unsigned int *len); + + bool (*restart)(struct virtqueue *vq); + + void (*shutdown)(struct virtqueue *vq); +}; + +/** + * virtio_device - representation of a device using virtio + * @index: unique position on the virtio bus + * @dev: underlying device. + * @id: the device type identification (used to match it with a driver). + * @config: the configuration ops for this device. + * @priv: private pointer for the driver's use. + */ +struct virtio_device +{ + int index; + struct device dev; + struct virtio_device_id id; + struct virtio_config_ops *config; + void *priv; +}; + +int register_virtio_device(struct virtio_device *dev); +void unregister_virtio_device(struct virtio_device *dev); + +/** + * virtio_driver - operations for a virtio I/O driver + * @driver: underlying device driver (populate name and owner). + * @id_table: the ids serviced by this driver. + * @probe: the function to call when a device is found. Returns a token for + * remove, or PTR_ERR(). + * @remove: the function when a device is removed. + */ +struct virtio_driver { + struct device_driver driver; + const struct virtio_device_id *id_table; + int (*probe)(struct virtio_device *dev); + void (*remove)(struct virtio_device *dev); +}; + +int register_virtio_driver(struct virtio_driver *drv); +void unregister_virtio_driver(struct virtio_driver *drv); +#endif /* _LINUX_VIRTIO_H */ |