| 1 | #ifndef _LINUX_VIRTIO_H |
| 2 | #define _LINUX_VIRTIO_H |
| 3 | /* Everything a virtio driver needs to work with any particular virtio |
| 4 | * implementation. */ |
| 5 | #include <linux/types.h> |
| 6 | #include <linux/scatterlist.h> |
| 7 | #include <linux/spinlock.h> |
| 8 | #include <linux/device.h> |
| 9 | #include <linux/mod_devicetable.h> |
| 10 | #include <linux/gfp.h> |
| 11 | |
| 12 | /** |
| 13 | * virtqueue - a queue to register buffers for sending or receiving. |
| 14 | * @list: the chain of virtqueues for this device |
| 15 | * @callback: the function to call when buffers are consumed (can be NULL). |
| 16 | * @name: the name of this virtqueue (mainly for debugging) |
| 17 | * @vdev: the virtio device this queue was created for. |
| 18 | * @priv: a pointer for the virtqueue implementation to use. |
| 19 | */ |
| 20 | struct virtqueue { |
| 21 | struct list_head list; |
| 22 | void (*callback)(struct virtqueue *vq); |
| 23 | const char *name; |
| 24 | struct virtio_device *vdev; |
| 25 | void *priv; |
| 26 | }; |
| 27 | |
| 28 | /** |
| 29 | * operations for virtqueue |
| 30 | * virtqueue_add_buf: expose buffer to other end |
| 31 | * vq: the struct virtqueue we're talking about. |
| 32 | * sg: the description of the buffer(s). |
| 33 | * out_num: the number of sg readable by other side |
| 34 | * in_num: the number of sg which are writable (after readable ones) |
| 35 | * data: the token identifying the buffer. |
| 36 | * gfp: how to do memory allocations (if necessary). |
| 37 | * Returns remaining capacity of queue (sg segments) or a negative error. |
| 38 | * virtqueue_kick: update after add_buf |
| 39 | * vq: the struct virtqueue |
| 40 | * After one or more add_buf calls, invoke this to kick the other side. |
| 41 | * virtqueue_get_buf: get the next used buffer |
| 42 | * vq: the struct virtqueue we're talking about. |
| 43 | * len: the length written into the buffer |
| 44 | * Returns NULL or the "data" token handed to add_buf. |
| 45 | * virtqueue_disable_cb: disable callbacks |
| 46 | * vq: the struct virtqueue we're talking about. |
| 47 | * Note that this is not necessarily synchronous, hence unreliable and only |
| 48 | * useful as an optimization. |
| 49 | * virtqueue_enable_cb: restart callbacks after disable_cb. |
| 50 | * vq: the struct virtqueue we're talking about. |
| 51 | * This re-enables callbacks; it returns "false" if there are pending |
| 52 | * buffers in the queue, to detect a possible race between the driver |
| 53 | * checking for more work, and enabling callbacks. |
| 54 | * virtqueue_enable_cb_delayed: restart callbacks after disable_cb. |
| 55 | * vq: the struct virtqueue we're talking about. |
| 56 | * This re-enables callbacks but hints to the other side to delay |
| 57 | * interrupts until most of the available buffers have been processed; |
| 58 | * it returns "false" if there are many pending buffers in the queue, |
| 59 | * to detect a possible race between the driver checking for more work, |
| 60 | * and enabling callbacks. |
| 61 | * virtqueue_detach_unused_buf: detach first unused buffer |
| 62 | * vq: the struct virtqueue we're talking about. |
| 63 | * Returns NULL or the "data" token handed to add_buf |
| 64 | * |
| 65 | * Locking rules are straightforward: the driver is responsible for |
| 66 | * locking. No two operations may be invoked simultaneously, with the exception |
| 67 | * of virtqueue_disable_cb. |
| 68 | * |
| 69 | * All operations can be called in any context. |
| 70 | */ |
| 71 | |
| 72 | int virtqueue_add_buf_gfp(struct virtqueue *vq, |
| 73 | struct scatterlist sg[], |
| 74 | unsigned int out_num, |
| 75 | unsigned int in_num, |
| 76 | void *data, |
| 77 | gfp_t gfp); |
| 78 | |
| 79 | static inline int virtqueue_add_buf(struct virtqueue *vq, |
| 80 | struct scatterlist sg[], |
| 81 | unsigned int out_num, |
| 82 | unsigned int in_num, |
| 83 | void *data) |
| 84 | { |
| 85 | return virtqueue_add_buf_gfp(vq, sg, out_num, in_num, data, GFP_ATOMIC); |
| 86 | } |
| 87 | |
| 88 | void virtqueue_kick(struct virtqueue *vq); |
| 89 | |
| 90 | void *virtqueue_get_buf(struct virtqueue *vq, unsigned int *len); |
| 91 | |
| 92 | void virtqueue_disable_cb(struct virtqueue *vq); |
| 93 | |
| 94 | bool virtqueue_enable_cb(struct virtqueue *vq); |
| 95 | |
| 96 | bool virtqueue_enable_cb_delayed(struct virtqueue *vq); |
| 97 | |
| 98 | void *virtqueue_detach_unused_buf(struct virtqueue *vq); |
| 99 | |
| 100 | /** |
| 101 | * virtio_device - representation of a device using virtio |
| 102 | * @index: unique position on the virtio bus |
| 103 | * @dev: underlying device. |
| 104 | * @id: the device type identification (used to match it with a driver). |
| 105 | * @config: the configuration ops for this device. |
| 106 | * @vqs: the list of virtqueues for this device. |
| 107 | * @features: the features supported by both driver and device. |
| 108 | * @priv: private pointer for the driver's use. |
| 109 | */ |
| 110 | struct virtio_device { |
| 111 | int index; |
| 112 | struct device dev; |
| 113 | struct virtio_device_id id; |
| 114 | struct virtio_config_ops *config; |
| 115 | struct list_head vqs; |
| 116 | /* Note that this is a Linux set_bit-style bitmap. */ |
| 117 | unsigned long features[1]; |
| 118 | void *priv; |
| 119 | }; |
| 120 | |
| 121 | #define dev_to_virtio(dev) container_of(dev, struct virtio_device, dev) |
| 122 | int register_virtio_device(struct virtio_device *dev); |
| 123 | void unregister_virtio_device(struct virtio_device *dev); |
| 124 | |
| 125 | /** |
| 126 | * virtio_driver - operations for a virtio I/O driver |
| 127 | * @driver: underlying device driver (populate name and owner). |
| 128 | * @id_table: the ids serviced by this driver. |
| 129 | * @feature_table: an array of feature numbers supported by this device. |
| 130 | * @feature_table_size: number of entries in the feature table array. |
| 131 | * @probe: the function to call when a device is found. Returns 0 or -errno. |
| 132 | * @remove: the function when a device is removed. |
| 133 | * @config_changed: optional function to call when the device configuration |
| 134 | * changes; may be called in interrupt context. |
| 135 | */ |
| 136 | struct virtio_driver { |
| 137 | struct device_driver driver; |
| 138 | const struct virtio_device_id *id_table; |
| 139 | const unsigned int *feature_table; |
| 140 | unsigned int feature_table_size; |
| 141 | int (*probe)(struct virtio_device *dev); |
| 142 | void (*remove)(struct virtio_device *dev); |
| 143 | void (*config_changed)(struct virtio_device *dev); |
| 144 | }; |
| 145 | |
| 146 | int register_virtio_driver(struct virtio_driver *drv); |
| 147 | void unregister_virtio_driver(struct virtio_driver *drv); |
| 148 | #endif /* _LINUX_VIRTIO_H */ |