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  * virtio_device - representation of a device using virtio
  95  * @index: unique position on the virtio bus
  96  * @failed: saved value for VIRTIO_CONFIG_S_FAILED bit (for restore)
  97  * @config_enabled: configuration change reporting enabled
  98  * @config_change_pending: configuration change reported while disabled
  99  * @config_lock: protects configuration change reporting
 100  * @dev: underlying device.
 101  * @id: the device type identification (used to match it with a driver).
 102  * @config: the configuration ops for this device.
 103  * @vringh_config: configuration ops for host vrings.
 104  * @vqs: the list of virtqueues for this device.
 105  * @features: the features supported by both driver and device.
 106  * @priv: private pointer for the driver's use.
 107  */
 108 struct virtio_device {
 109         int index;
 110         bool failed;
 111         bool config_enabled;
 112         bool config_change_pending;
 113         spinlock_t config_lock;
 114         struct device dev;
 115         struct virtio_device_id id;
 116         const struct virtio_config_ops *config;
 117         const struct vringh_config_ops *vringh_config;
 118         struct list_head vqs;
 119         u64 features;
 120         void *priv;
 121 };
 122
 123 static inline struct virtio_device *dev_to_virtio(struct device *_dev)
 124 {
 125         return container_of(_dev, struct virtio_device, dev);
 126 }
 127
 128 void virtio_add_status(struct virtio_device *dev, unsigned int status);
 129 int register_virtio_device(struct virtio_device *dev);
 130 void unregister_virtio_device(struct virtio_device *dev);
 131
 132 void virtio_break_device(struct virtio_device *dev);
 133
 134 void virtio_config_changed(struct virtio_device *dev);
 135 void virtio_config_disable(struct virtio_device *dev);
 136 void virtio_config_enable(struct virtio_device *dev);
 137 int virtio_finalize_features(struct virtio_device *dev);
 138 #ifdef CONFIG_PM_SLEEP
 139 int virtio_device_freeze(struct virtio_device *dev);
 140 int virtio_device_restore(struct virtio_device *dev);
 141 #endif
 142
 143 size_t virtio_max_dma_size(struct virtio_device *vdev);
 144
 145 #define virtio_device_for_each_vq(vdev, vq) \
 146         list_for_each_entry(vq, &vdev->vqs, list)
 147
 148 /**
 149  * virtio_driver - operations for a virtio I/O driver
 150  * @driver: underlying device driver (populate name and owner).
 151  * @id_table: the ids serviced by this driver.
 152  * @feature_table: an array of feature numbers supported by this driver.
 153  * @feature_table_size: number of entries in the feature table array.
 154  * @feature_table_legacy: same as feature_table but when working in legacy mode.
 155  * @feature_table_size_legacy: number of entries in feature table legacy array.
 156  * @probe: the function to call when a device is found.  Returns 0 or -errno.
 157  * @scan: optional function to call after successful probe; intended
 158  *    for virtio-scsi to invoke a scan.
 159  * @remove: the function to call when a device is removed.
 160  * @config_changed: optional function to call when the device configuration
 161  *    changes; may be called in interrupt context.
 162  * @freeze: optional function to call during suspend/hibernation.
 163  * @restore: optional function to call on resume.
 164  */
 165 struct virtio_driver {
 166         struct device_driver driver;
 167         const struct virtio_device_id *id_table;
 168         const unsigned int *feature_table;
 169         unsigned int feature_table_size;
 170         const unsigned int *feature_table_legacy;
 171         unsigned int feature_table_size_legacy;
 172         int (*validate)(struct virtio_device *dev);
 173         int (*probe)(struct virtio_device *dev);
 174         void (*scan)(struct virtio_device *dev);
 175         void (*remove)(struct virtio_device *dev);
 176         void (*config_changed)(struct virtio_device *dev);
 177 #ifdef CONFIG_PM
 178         int (*freeze)(struct virtio_device *dev);
 179         int (*restore)(struct virtio_device *dev);
 180 #endif
 181 };
 182
 183 static inline struct virtio_driver *drv_to_virtio(struct device_driver *drv)
 184 {
 185         return container_of(drv, struct virtio_driver, driver);
 186 }
 187
 188 int register_virtio_driver(struct virtio_driver *drv);
 189 void unregister_virtio_driver(struct virtio_driver *drv);
 190
 191 /* module_virtio_driver() - Helper macro for drivers that don't do
 192  * anything special in module init/exit.  This eliminates a lot of
 193  * boilerplate.  Each module may only use this macro once, and
 194  * calling it replaces module_init() and module_exit()
 195  */
 196 #define module_virtio_driver(__virtio_driver) \
 197         module_driver(__virtio_driver, register_virtio_driver, \
 198                         unregister_virtio_driver)
 199 #endif /* _LINUX_VIRTIO_H */