#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). * @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 { void (*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. * @disable_cb: disable callbacks * vq: the struct virtqueue we're talking about. * Note that this is not necessarily synchronous, hence unreliable and only * useful as an optimization. * @enable_cb: restart callbacks after disable_cb. * vq: the struct virtqueue we're talking about. * This re-enables callbacks; it returns "false" if there are pending * buffers in the queue, to detect a possible race between the driver * checking for more work, and enabling callbacks. * * Locking rules are straightforward: the driver is responsible for * locking. No two operations may be invoked simultaneously, with the exception * of @disable_cb. * * 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); void (*disable_cb)(struct virtqueue *vq); bool (*enable_cb)(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. * @config_changed: optional function to call when the device configuration * changes; may be called in interrupt context. */ 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); void (*config_changed)(struct virtio_device *dev); }; int register_virtio_driver(struct virtio_driver *drv); void unregister_virtio_driver(struct virtio_driver *drv); #endif /* _LINUX_VIRTIO_H */