include/linux/virtio.h

   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 #include <linux/vringh.h>
  12
  13 /**
  14  * virtqueue - a queue to register buffers for sending or receiving.
  15  * @list: the chain of virtqueues for this device
  16  * @callback: the function to call when buffers are consumed (can be NULL).
  17  * @name: the name of this virtqueue (mainly for debugging)
  18  * @vdev: the virtio device this queue was created for.
  19  * @priv: a pointer for the virtqueue implementation to use.
  20  * @index: the zero-based ordinal number for this queue.
  21  * @num_free: number of elements we expect to be able to fit.
  22  *
  23  * A note on @num_free: with indirect buffers, each buffer needs one
  24  * element in the queue, otherwise a buffer will need one element per
  25  * sg element.
  26  */
  27 struct virtqueue {
  28         struct list_head list;
  29         void (*callback)(struct virtqueue *vq);
  30         const char *name;
  31         struct virtio_device *vdev;
  32         unsigned int index;
  33         unsigned int num_free;
  34         void *priv;
  35 };
  36
  37 int virtqueue_add_outbuf(struct virtqueue *vq,
  38                          struct scatterlist sg[], unsigned int num,
  39                          void *data,
  40                          gfp_t gfp);
  41
  42 int virtqueue_add_inbuf(struct virtqueue *vq,
  43                         struct scatterlist sg[], unsigned int num,
  44                         void *data,
  45                         gfp_t gfp);
  46
  47 int virtqueue_add_sgs(struct virtqueue *vq,
  48                       struct scatterlist *sgs[],
  49                       unsigned int out_sgs,
  50                       unsigned int in_sgs,
  51                       void *data,
  52                       gfp_t gfp);
  53
  54 bool virtqueue_kick(struct virtqueue *vq);
  55
  56 bool virtqueue_kick_prepare(struct virtqueue *vq);
  57
  58 bool virtqueue_notify(struct virtqueue *vq);
  59
  60 void *virtqueue_get_buf(struct virtqueue *vq, unsigned int *len);
  61
  62 void virtqueue_disable_cb(struct virtqueue *vq);
  63
  64 bool virtqueue_enable_cb(struct virtqueue *vq);
  65
  66 unsigned virtqueue_enable_cb_prepare(struct virtqueue *vq);
  67
  68 bool virtqueue_poll(struct virtqueue *vq, unsigned);
  69
  70 bool virtqueue_enable_cb_delayed(struct virtqueue *vq);
  71
  72 void *virtqueue_detach_unused_buf(struct virtqueue *vq);
  73
  74 unsigned int virtqueue_get_vring_size(struct virtqueue *vq);
  75
  76 bool virtqueue_is_broken(struct virtqueue *vq);
  77
  78 const struct vring *virtqueue_get_vring(struct virtqueue *vq);
  79 dma_addr_t virtqueue_get_desc_addr(struct virtqueue *vq);
  80 dma_addr_t virtqueue_get_avail_addr(struct virtqueue *vq);
  81 dma_addr_t virtqueue_get_used_addr(struct virtqueue *vq);
  82
  83 /*
  84  * Legacy accessors -- in almost all cases, these are the wrong functions
  85  * to use.
  86  */
  87 static inline void *virtqueue_get_desc(struct virtqueue *vq)
  88 {
  89         return virtqueue_get_vring(vq)->desc;
  90 }
  91 static inline void *virtqueue_get_avail(struct virtqueue *vq)
  92 {
  93         return virtqueue_get_vring(vq)->avail;
  94 }
  95 static inline void *virtqueue_get_used(struct virtqueue *vq)
  96 {
  97         return virtqueue_get_vring(vq)->used;
  98 }
  99
 100 /**
 101  * virtio_device - representation of a device using virtio
 102  * @index: unique position on the virtio bus
 103  * @failed: saved value for VIRTIO_CONFIG_S_FAILED bit (for restore)
 104  * @config_enabled: configuration change reporting enabled
 105  * @config_change_pending: configuration change reported while disabled
 106  * @config_lock: protects configuration change reporting
 107  * @dev: underlying device.
 108  * @id: the device type identification (used to match it with a driver).
 109  * @config: the configuration ops for this device.
 110  * @vringh_config: configuration ops for host vrings.
 111  * @vqs: the list of virtqueues for this device.
 112  * @features: the features supported by both driver and device.
 113  * @priv: private pointer for the driver's use.
 114  */
 115 struct virtio_device {
 116         int index;
 117         bool failed;
 118         bool config_enabled;
 119         bool config_change_pending;
 120         spinlock_t config_lock;
 121         struct device dev;
 122         struct virtio_device_id id;
 123         const struct virtio_config_ops *config;
 124         const struct vringh_config_ops *vringh_config;
 125         struct list_head vqs;
 126         u64 features;
 127         void *priv;
 128 };
 129
 130 static inline struct virtio_device *dev_to_virtio(struct device *_dev)
 131 {
 132         return container_of(_dev, struct virtio_device, dev);
 133 }
 134
 135 int register_virtio_device(struct virtio_device *dev);
 136 void unregister_virtio_device(struct virtio_device *dev);
 137
 138 void virtio_break_device(struct virtio_device *dev);
 139
 140 void virtio_config_changed(struct virtio_device *dev);
 141 #ifdef CONFIG_PM_SLEEP
 142 int virtio_device_freeze(struct virtio_device *dev);
 143 int virtio_device_restore(struct virtio_device *dev);
 144 #endif
 145
 146 /**
 147  * virtio_driver - operations for a virtio I/O driver
 148  * @driver: underlying device driver (populate name and owner).
 149  * @id_table: the ids serviced by this driver.
 150  * @feature_table: an array of feature numbers supported by this driver.
 151  * @feature_table_size: number of entries in the feature table array.
 152  * @feature_table_legacy: same as feature_table but when working in legacy mode.
 153  * @feature_table_size_legacy: number of entries in feature table legacy array.
 154  * @probe: the function to call when a device is found.  Returns 0 or -errno.
 155  * @remove: the function to call when a device is removed.
 156  * @config_changed: optional function to call when the device configuration
 157  *    changes; may be called in interrupt context.
 158  */
 159 struct virtio_driver {
 160         struct device_driver driver;
 161         const struct virtio_device_id *id_table;
 162         const unsigned int *feature_table;
 163         unsigned int feature_table_size;
 164         const unsigned int *feature_table_legacy;
 165         unsigned int feature_table_size_legacy;
 166         int (*probe)(struct virtio_device *dev);
 167         void (*scan)(struct virtio_device *dev);
 168         void (*remove)(struct virtio_device *dev);
 169         void (*config_changed)(struct virtio_device *dev);
 170 #ifdef CONFIG_PM
 171         int (*freeze)(struct virtio_device *dev);
 172         int (*restore)(struct virtio_device *dev);
 173 #endif
 174 };
 175
 176 static inline struct virtio_driver *drv_to_virtio(struct device_driver *drv)
 177 {
 178         return container_of(drv, struct virtio_driver, driver);
 179 }
 180
 181 int register_virtio_driver(struct virtio_driver *drv);
 182 void unregister_virtio_driver(struct virtio_driver *drv);
 183
 184 /* module_virtio_driver() - Helper macro for drivers that don't do
 185  * anything special in module init/exit.  This eliminates a lot of
 186  * boilerplate.  Each module may only use this macro once, and
 187  * calling it replaces module_init() and module_exit()
 188  */
 189 #define module_virtio_driver(__virtio_driver) \
 190         module_driver(__virtio_driver, register_virtio_driver, \
 191                         unregister_virtio_driver)
 192 #endif /* _LINUX_VIRTIO_H */