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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 | #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 */ |