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
  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_inbuf_ctx(struct virtqueue *vq,
  48                             struct scatterlist sg[], unsigned int num,
  49                             void *data,
  50                             void *ctx,
  51                             gfp_t gfp);
  52
  53 int virtqueue_add_sgs(struct virtqueue *vq,
  54                       struct scatterlist *sgs[],
  55                       unsigned int out_sgs,
  56                       unsigned int in_sgs,
  57                       void *data,
  58                       gfp_t gfp);
  59
  60 bool virtqueue_kick(struct virtqueue *vq);
  61
  62 bool virtqueue_kick_prepare(struct virtqueue *vq);
  63
  64 bool virtqueue_notify(struct virtqueue *vq);
  65
  66 void *virtqueue_get_buf(struct virtqueue *vq, unsigned int *len);
  67
  68 void *virtqueue_get_buf_ctx(struct virtqueue *vq, unsigned int *len,
  69                             void **ctx);
  70
  71 void virtqueue_disable_cb(struct virtqueue *vq);
  72
  73 bool virtqueue_enable_cb(struct virtqueue *vq);
  74
  75 unsigned virtqueue_enable_cb_prepare(struct virtqueue *vq);
  76
  77 bool virtqueue_poll(struct virtqueue *vq, unsigned);
  78
  79 bool virtqueue_enable_cb_delayed(struct virtqueue *vq);
  80
  81 void *virtqueue_detach_unused_buf(struct virtqueue *vq);
  82
  83 unsigned int virtqueue_get_vring_size(struct virtqueue *vq);
  84
  85 bool virtqueue_is_broken(struct virtqueue *vq);
  86
  87 const struct vring *virtqueue_get_vring(struct virtqueue *vq);
  88 dma_addr_t virtqueue_get_desc_addr(struct virtqueue *vq);
  89 dma_addr_t virtqueue_get_avail_addr(struct virtqueue *vq);
  90 dma_addr_t virtqueue_get_used_addr(struct virtqueue *vq);
  91
  92 /**
  93  * virtio_device - representation of a device using virtio
  94  * @index: unique position on the virtio bus
  95  * @failed: saved value for VIRTIO_CONFIG_S_FAILED bit (for restore)
  96  * @config_enabled: configuration change reporting enabled
  97  * @config_change_pending: configuration change reported while disabled
  98  * @config_lock: protects configuration change reporting
  99  * @dev: underlying device.
 100  * @id: the device type identification (used to match it with a driver).
 101  * @config: the configuration ops for this device.
 102  * @vringh_config: configuration ops for host vrings.
 103  * @vqs: the list of virtqueues for this device.
 104  * @features: the features supported by both driver and device.
 105  * @priv: private pointer for the driver's use.
 106  */
 107 struct virtio_device {
 108         int index;
 109         bool failed;
 110         bool config_enabled;
 111         bool config_change_pending;
 112         spinlock_t config_lock;
 113         struct device dev;
 114         struct virtio_device_id id;
 115         const struct virtio_config_ops *config;
 116         const struct vringh_config_ops *vringh_config;
 117         struct list_head vqs;
 118         u64 features;
 119         void *priv;
 120 };
 121
 122 static inline struct virtio_device *dev_to_virtio(struct device *_dev)
 123 {
 124         return container_of(_dev, struct virtio_device, dev);
 125 }
 126
 127 void virtio_add_status(struct virtio_device *dev, unsigned int status);
 128 int register_virtio_device(struct virtio_device *dev);
 129 void unregister_virtio_device(struct virtio_device *dev);
 130 bool is_virtio_device(struct device *dev);
 131
 132 void virtio_break_device(struct virtio_device *dev);
 133
 134 void virtio_config_changed(struct virtio_device *dev);
 135 int virtio_finalize_features(struct virtio_device *dev);
 136 #ifdef CONFIG_PM_SLEEP
 137 int virtio_device_freeze(struct virtio_device *dev);
 138 int virtio_device_restore(struct virtio_device *dev);
 139 #endif
 140
 141 size_t virtio_max_dma_size(struct virtio_device *vdev);
 142
 143 #define virtio_device_for_each_vq(vdev, vq) \
 144         list_for_each_entry(vq, &vdev->vqs, list)
 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  * @scan: optional function to call after successful probe; intended
 156  *    for virtio-scsi to invoke a scan.
 157  * @remove: the function to call when a device is removed.
 158  * @config_changed: optional function to call when the device configuration
 159  *    changes; may be called in interrupt context.
 160  * @freeze: optional function to call during suspend/hibernation.
 161  * @restore: optional function to call on resume.
 162  */
 163 struct virtio_driver {
 164         struct device_driver driver;
 165         const struct virtio_device_id *id_table;
 166         const unsigned int *feature_table;
 167         unsigned int feature_table_size;
 168         const unsigned int *feature_table_legacy;
 169         unsigned int feature_table_size_legacy;
 170         int (*validate)(struct virtio_device *dev);
 171         int (*probe)(struct virtio_device *dev);
 172         void (*scan)(struct virtio_device *dev);
 173         void (*remove)(struct virtio_device *dev);
 174         void (*config_changed)(struct virtio_device *dev);
 175 #ifdef CONFIG_PM
 176         int (*freeze)(struct virtio_device *dev);
 177         int (*restore)(struct virtio_device *dev);
 178 #endif
 179 };
 180
 181 static inline struct virtio_driver *drv_to_virtio(struct device_driver *drv)
 182 {
 183         return container_of(drv, struct virtio_driver, driver);
 184 }
 185
 186 int register_virtio_driver(struct virtio_driver *drv);
 187 void unregister_virtio_driver(struct virtio_driver *drv);
 188
 189 /* module_virtio_driver() - Helper macro for drivers that don't do
 190  * anything special in module init/exit.  This eliminates a lot of
 191  * boilerplate.  Each module may only use this macro once, and
 192  * calling it replaces module_init() and module_exit()
 193  */
 194 #define module_virtio_driver(__virtio_driver) \
 195         module_driver(__virtio_driver, register_virtio_driver, \
 196                         unregister_virtio_driver)
 197 #endif /* _LINUX_VIRTIO_H */