include/linux/virtio.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _LINUX_VIRTIO_H
   3 #define _LINUX_VIRTIO_H
   4 /* Everything a virtio driver needs to work with any particular virtio
   5  * implementation. */
   6 #include <linux/types.h>
   7 #include <linux/scatterlist.h>
   8 #include <linux/spinlock.h>
   9 #include <linux/device.h>
  10 #include <linux/mod_devicetable.h>
  11 #include <linux/gfp.h>
  12 #include <linux/vringh.h>
  13
  14 /**
  15  * virtqueue - a queue to register buffers for sending or receiving.
  16  * @list: the chain of virtqueues for this device
  17  * @callback: the function to call when buffers are consumed (can be NULL).
  18  * @name: the name of this virtqueue (mainly for debugging)
  19  * @vdev: the virtio device this queue was created for.
  20  * @priv: a pointer for the virtqueue implementation to use.
  21  * @index: the zero-based ordinal number for this queue.
  22  * @num_free: number of elements we expect to be able to fit.
  23  *
  24  * A note on @num_free: with indirect buffers, each buffer needs one
  25  * element in the queue, otherwise a buffer will need one element per
  26  * sg element.
  27  */
  28 struct virtqueue {
  29         struct list_head list;
  30         void (*callback)(struct virtqueue *vq);
  31         const char *name;
  32         struct virtio_device *vdev;
  33         unsigned int index;
  34         unsigned int num_free;
  35         void *priv;
  36 };
  37
  38 int virtqueue_add_outbuf(struct virtqueue *vq,
  39                          struct scatterlist sg[], unsigned int num,
  40                          void *data,
  41                          gfp_t gfp);
  42
  43 int virtqueue_add_inbuf(struct virtqueue *vq,
  44                         struct scatterlist sg[], unsigned int num,
  45                         void *data,
  46                         gfp_t gfp);
  47
  48 int virtqueue_add_inbuf_ctx(struct virtqueue *vq,
  49                             struct scatterlist sg[], unsigned int num,
  50                             void *data,
  51                             void *ctx,
  52                             gfp_t gfp);
  53
  54 int virtqueue_add_sgs(struct virtqueue *vq,
  55                       struct scatterlist *sgs[],
  56                       unsigned int out_sgs,
  57                       unsigned int in_sgs,
  58                       void *data,
  59                       gfp_t gfp);
  60
  61 bool virtqueue_kick(struct virtqueue *vq);
  62
  63 bool virtqueue_kick_prepare(struct virtqueue *vq);
  64
  65 bool virtqueue_notify(struct virtqueue *vq);
  66
  67 void *virtqueue_get_buf(struct virtqueue *vq, unsigned int *len);
  68
  69 void *virtqueue_get_buf_ctx(struct virtqueue *vq, unsigned int *len,
  70                             void **ctx);
  71
  72 void virtqueue_disable_cb(struct virtqueue *vq);
  73
  74 bool virtqueue_enable_cb(struct virtqueue *vq);
  75
  76 unsigned virtqueue_enable_cb_prepare(struct virtqueue *vq);
  77
  78 bool virtqueue_poll(struct virtqueue *vq, unsigned);
  79
  80 bool virtqueue_enable_cb_delayed(struct virtqueue *vq);
  81
  82 void *virtqueue_detach_unused_buf(struct virtqueue *vq);
  83
  84 unsigned int virtqueue_get_vring_size(struct virtqueue *vq);
  85
  86 bool virtqueue_is_broken(struct virtqueue *vq);
  87
  88 const struct vring *virtqueue_get_vring(struct virtqueue *vq);
  89 dma_addr_t virtqueue_get_desc_addr(struct virtqueue *vq);
  90 dma_addr_t virtqueue_get_avail_addr(struct virtqueue *vq);
  91 dma_addr_t virtqueue_get_used_addr(struct virtqueue *vq);
  92
  93 /*
  94  * Legacy accessors -- in almost all cases, these are the wrong functions
  95  * to use.
  96  */
  97 static inline void *virtqueue_get_desc(struct virtqueue *vq)
  98 {
  99         return virtqueue_get_vring(vq)->desc;
 100 }
 101 static inline void *virtqueue_get_avail(struct virtqueue *vq)
 102 {
 103         return virtqueue_get_vring(vq)->avail;
 104 }
 105 static inline void *virtqueue_get_used(struct virtqueue *vq)
 106 {
 107         return virtqueue_get_vring(vq)->used;
 108 }
 109
 110 /**
 111  * virtio_device - representation of a device using virtio
 112  * @index: unique position on the virtio bus
 113  * @failed: saved value for VIRTIO_CONFIG_S_FAILED bit (for restore)
 114  * @config_enabled: configuration change reporting enabled
 115  * @config_change_pending: configuration change reported while disabled
 116  * @config_lock: protects configuration change reporting
 117  * @dev: underlying device.
 118  * @id: the device type identification (used to match it with a driver).
 119  * @config: the configuration ops for this device.
 120  * @vringh_config: configuration ops for host vrings.
 121  * @vqs: the list of virtqueues for this device.
 122  * @features: the features supported by both driver and device.
 123  * @priv: private pointer for the driver's use.
 124  */
 125 struct virtio_device {
 126         int index;
 127         bool failed;
 128         bool config_enabled;
 129         bool config_change_pending;
 130         spinlock_t config_lock;
 131         struct device dev;
 132         struct virtio_device_id id;
 133         const struct virtio_config_ops *config;
 134         const struct vringh_config_ops *vringh_config;
 135         struct list_head vqs;
 136         u64 features;
 137         void *priv;
 138 };
 139
 140 static inline struct virtio_device *dev_to_virtio(struct device *_dev)
 141 {
 142         return container_of(_dev, struct virtio_device, dev);
 143 }
 144
 145 void virtio_add_status(struct virtio_device *dev, unsigned int status);
 146 int register_virtio_device(struct virtio_device *dev);
 147 void unregister_virtio_device(struct virtio_device *dev);
 148
 149 void virtio_break_device(struct virtio_device *dev);
 150
 151 void virtio_config_changed(struct virtio_device *dev);
 152 void virtio_config_disable(struct virtio_device *dev);
 153 void virtio_config_enable(struct virtio_device *dev);
 154 int virtio_finalize_features(struct virtio_device *dev);
 155 #ifdef CONFIG_PM_SLEEP
 156 int virtio_device_freeze(struct virtio_device *dev);
 157 int virtio_device_restore(struct virtio_device *dev);
 158 #endif
 159
 160 #define virtio_device_for_each_vq(vdev, vq) \
 161         list_for_each_entry(vq, &vdev->vqs, list)
 162
 163 /**
 164  * virtio_driver - operations for a virtio I/O driver
 165  * @driver: underlying device driver (populate name and owner).
 166  * @id_table: the ids serviced by this driver.
 167  * @feature_table: an array of feature numbers supported by this driver.
 168  * @feature_table_size: number of entries in the feature table array.
 169  * @feature_table_legacy: same as feature_table but when working in legacy mode.
 170  * @feature_table_size_legacy: number of entries in feature table legacy array.
 171  * @probe: the function to call when a device is found.  Returns 0 or -errno.
 172  * @scan: optional function to call after successful probe; intended
 173  *    for virtio-scsi to invoke a scan.
 174  * @remove: the function to call when a device is removed.
 175  * @config_changed: optional function to call when the device configuration
 176  *    changes; may be called in interrupt context.
 177  * @freeze: optional function to call during suspend/hibernation.
 178  * @restore: optional function to call on resume.
 179  */
 180 struct virtio_driver {
 181         struct device_driver driver;
 182         const struct virtio_device_id *id_table;
 183         const unsigned int *feature_table;
 184         unsigned int feature_table_size;
 185         const unsigned int *feature_table_legacy;
 186         unsigned int feature_table_size_legacy;
 187         int (*validate)(struct virtio_device *dev);
 188         int (*probe)(struct virtio_device *dev);
 189         void (*scan)(struct virtio_device *dev);
 190         void (*remove)(struct virtio_device *dev);
 191         void (*config_changed)(struct virtio_device *dev);
 192 #ifdef CONFIG_PM
 193         int (*freeze)(struct virtio_device *dev);
 194         int (*restore)(struct virtio_device *dev);
 195 #endif
 196 };
 197
 198 static inline struct virtio_driver *drv_to_virtio(struct device_driver *drv)
 199 {
 200         return container_of(drv, struct virtio_driver, driver);
 201 }
 202
 203 int register_virtio_driver(struct virtio_driver *drv);
 204 void unregister_virtio_driver(struct virtio_driver *drv);
 205
 206 /* module_virtio_driver() - Helper macro for drivers that don't do
 207  * anything special in module init/exit.  This eliminates a lot of
 208  * boilerplate.  Each module may only use this macro once, and
 209  * calling it replaces module_init() and module_exit()
 210  */
 211 #define module_virtio_driver(__virtio_driver) \
 212         module_driver(__virtio_driver, register_virtio_driver, \
 213                         unregister_virtio_driver)
 214 #endif /* _LINUX_VIRTIO_H */