include/linux/virtio_config.h

   1 #ifndef _LINUX_VIRTIO_CONFIG_H
   2 #define _LINUX_VIRTIO_CONFIG_H
   3
   4 #include <linux/err.h>
   5 #include <linux/bug.h>
   6 #include <linux/virtio.h>
   7 #include <uapi/linux/virtio_config.h>
   8
   9 /**
  10  * virtio_config_ops - operations for configuring a virtio device
  11  * @get: read the value of a configuration field
  12  *      vdev: the virtio_device
  13  *      offset: the offset of the configuration field
  14  *      buf: the buffer to write the field value into.
  15  *      len: the length of the buffer
  16  * @set: write the value of a configuration field
  17  *      vdev: the virtio_device
  18  *      offset: the offset of the configuration field
  19  *      buf: the buffer to read the field value from.
  20  *      len: the length of the buffer
  21  * @get_status: read the status byte
  22  *      vdev: the virtio_device
  23  *      Returns the status byte
  24  * @set_status: write the status byte
  25  *      vdev: the virtio_device
  26  *      status: the new status byte
  27  * @reset: reset the device
  28  *      vdev: the virtio device
  29  *      After this, status and feature negotiation must be done again
  30  *      Device must not be reset from its vq/config callbacks, or in
  31  *      parallel with being added/removed.
  32  * @find_vqs: find virtqueues and instantiate them.
  33  *      vdev: the virtio_device
  34  *      nvqs: the number of virtqueues to find
  35  *      vqs: on success, includes new virtqueues
  36  *      callbacks: array of callbacks, for each virtqueue
  37  *              include a NULL entry for vqs that do not need a callback
  38  *      names: array of virtqueue names (mainly for debugging)
  39  *              include a NULL entry for vqs unused by driver
  40  *      Returns 0 on success or error status
  41  * @del_vqs: free virtqueues found by find_vqs().
  42  * @get_features: get the array of feature bits for this device.
  43  *      vdev: the virtio_device
  44  *      Returns the first 32 feature bits (all we currently need).
  45  * @finalize_features: confirm what device features we'll be using.
  46  *      vdev: the virtio_device
  47  *      This gives the final feature bits for the device: it can change
  48  *      the dev->feature bits if it wants.
  49  * @bus_name: return the bus name associated with the device
  50  *      vdev: the virtio_device
  51  *      This returns a pointer to the bus name a la pci_name from which
  52  *      the caller can then copy.
  53  * @set_vq_affinity: set the affinity for a virtqueue.
  54  */
  55 typedef void vq_callback_t(struct virtqueue *);
  56 struct virtio_config_ops {
  57         void (*get)(struct virtio_device *vdev, unsigned offset,
  58                     void *buf, unsigned len);
  59         void (*set)(struct virtio_device *vdev, unsigned offset,
  60                     const void *buf, unsigned len);
  61         u8 (*get_status)(struct virtio_device *vdev);
  62         void (*set_status)(struct virtio_device *vdev, u8 status);
  63         void (*reset)(struct virtio_device *vdev);
  64         int (*find_vqs)(struct virtio_device *, unsigned nvqs,
  65                         struct virtqueue *vqs[],
  66                         vq_callback_t *callbacks[],
  67                         const char *names[]);
  68         void (*del_vqs)(struct virtio_device *);
  69         u32 (*get_features)(struct virtio_device *vdev);
  70         void (*finalize_features)(struct virtio_device *vdev);
  71         const char *(*bus_name)(struct virtio_device *vdev);
  72         int (*set_vq_affinity)(struct virtqueue *vq, int cpu);
  73 };
  74
  75 /* If driver didn't advertise the feature, it will never appear. */
  76 void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
  77                                          unsigned int fbit);
  78
  79 /**
  80  * virtio_has_feature - helper to determine if this device has this feature.
  81  * @vdev: the device
  82  * @fbit: the feature bit
  83  */
  84 static inline bool virtio_has_feature(const struct virtio_device *vdev,
  85                                       unsigned int fbit)
  86 {
  87         /* Did you forget to fix assumptions on max features? */
  88         if (__builtin_constant_p(fbit))
  89                 BUILD_BUG_ON(fbit >= 32);
  90         else
  91                 BUG_ON(fbit >= 32);
  92
  93         if (fbit < VIRTIO_TRANSPORT_F_START)
  94                 virtio_check_driver_offered_feature(vdev, fbit);
  95
  96         return test_bit(fbit, vdev->features);
  97 }
  98
  99 static inline
 100 struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev,
 101                                         vq_callback_t *c, const char *n)
 102 {
 103         vq_callback_t *callbacks[] = { c };
 104         const char *names[] = { n };
 105         struct virtqueue *vq;
 106         int err = vdev->config->find_vqs(vdev, 1, &vq, callbacks, names);
 107         if (err < 0)
 108                 return ERR_PTR(err);
 109         return vq;
 110 }
 111
 112 /**
 113  * virtio_device_ready - enable vq use in probe function
 114  * @vdev: the device
 115  *
 116  * Driver must call this to use vqs in the probe function.
 117  *
 118  * Note: vqs are enabled automatically after probe returns.
 119  */
 120 static inline
 121 void virtio_device_ready(struct virtio_device *dev)
 122 {
 123         unsigned status = dev->config->get_status(dev);
 124
 125         BUG_ON(status & VIRTIO_CONFIG_S_DRIVER_OK);
 126         dev->config->set_status(dev, status | VIRTIO_CONFIG_S_DRIVER_OK);
 127 }
 128
 129 static inline
 130 const char *virtio_bus_name(struct virtio_device *vdev)
 131 {
 132         if (!vdev->config->bus_name)
 133                 return "virtio";
 134         return vdev->config->bus_name(vdev);
 135 }
 136
 137 /**
 138  * virtqueue_set_affinity - setting affinity for a virtqueue
 139  * @vq: the virtqueue
 140  * @cpu: the cpu no.
 141  *
 142  * Pay attention the function are best-effort: the affinity hint may not be set
 143  * due to config support, irq type and sharing.
 144  *
 145  */
 146 static inline
 147 int virtqueue_set_affinity(struct virtqueue *vq, int cpu)
 148 {
 149         struct virtio_device *vdev = vq->vdev;
 150         if (vdev->config->set_vq_affinity)
 151                 return vdev->config->set_vq_affinity(vq, cpu);
 152         return 0;
 153 }
 154
 155 /* Config space accessors. */
 156 #define virtio_cread(vdev, structname, member, ptr)                     \
 157         do {                                                            \
 158                 /* Must match the member's type, and be integer */      \
 159                 if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \
 160                         (*ptr) = 1;                                     \
 161                                                                         \
 162                 switch (sizeof(*ptr)) {                                 \
 163                 case 1:                                                 \
 164                         *(ptr) = virtio_cread8(vdev,                    \
 165                                                offsetof(structname, member)); \
 166                         break;                                          \
 167                 case 2:                                                 \
 168                         *(ptr) = virtio_cread16(vdev,                   \
 169                                                 offsetof(structname, member)); \
 170                         break;                                          \
 171                 case 4:                                                 \
 172                         *(ptr) = virtio_cread32(vdev,                   \
 173                                                 offsetof(structname, member)); \
 174                         break;                                          \
 175                 case 8:                                                 \
 176                         *(ptr) = virtio_cread64(vdev,                   \
 177                                                 offsetof(structname, member)); \
 178                         break;                                          \
 179                 default:                                                \
 180                         BUG();                                          \
 181                 }                                                       \
 182         } while(0)
 183
 184 /* Config space accessors. */
 185 #define virtio_cwrite(vdev, structname, member, ptr)                    \
 186         do {                                                            \
 187                 /* Must match the member's type, and be integer */      \
 188                 if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \
 189                         BUG_ON((*ptr) == 1);                            \
 190                                                                         \
 191                 switch (sizeof(*ptr)) {                                 \
 192                 case 1:                                                 \
 193                         virtio_cwrite8(vdev,                            \
 194                                        offsetof(structname, member),    \
 195                                        *(ptr));                         \
 196                         break;                                          \
 197                 case 2:                                                 \
 198                         virtio_cwrite16(vdev,                           \
 199                                         offsetof(structname, member),   \
 200                                         *(ptr));                        \
 201                         break;                                          \
 202                 case 4:                                                 \
 203                         virtio_cwrite32(vdev,                           \
 204                                         offsetof(structname, member),   \
 205                                         *(ptr));                        \
 206                         break;                                          \
 207                 case 8:                                                 \
 208                         virtio_cwrite64(vdev,                           \
 209                                         offsetof(structname, member),   \
 210                                         *(ptr));                        \
 211                         break;                                          \
 212                 default:                                                \
 213                         BUG();                                          \
 214                 }                                                       \
 215         } while(0)
 216
 217 static inline u8 virtio_cread8(struct virtio_device *vdev, unsigned int offset)
 218 {
 219         u8 ret;
 220         vdev->config->get(vdev, offset, &ret, sizeof(ret));
 221         return ret;
 222 }
 223
 224 static inline void virtio_cread_bytes(struct virtio_device *vdev,
 225                                       unsigned int offset,
 226                                       void *buf, size_t len)
 227 {
 228         vdev->config->get(vdev, offset, buf, len);
 229 }
 230
 231 static inline void virtio_cwrite8(struct virtio_device *vdev,
 232                                   unsigned int offset, u8 val)
 233 {
 234         vdev->config->set(vdev, offset, &val, sizeof(val));
 235 }
 236
 237 static inline u16 virtio_cread16(struct virtio_device *vdev,
 238                                  unsigned int offset)
 239 {
 240         u16 ret;
 241         vdev->config->get(vdev, offset, &ret, sizeof(ret));
 242         return ret;
 243 }
 244
 245 static inline void virtio_cwrite16(struct virtio_device *vdev,
 246                                    unsigned int offset, u16 val)
 247 {
 248         vdev->config->set(vdev, offset, &val, sizeof(val));
 249 }
 250
 251 static inline u32 virtio_cread32(struct virtio_device *vdev,
 252                                  unsigned int offset)
 253 {
 254         u32 ret;
 255         vdev->config->get(vdev, offset, &ret, sizeof(ret));
 256         return ret;
 257 }
 258
 259 static inline void virtio_cwrite32(struct virtio_device *vdev,
 260                                    unsigned int offset, u32 val)
 261 {
 262         vdev->config->set(vdev, offset, &val, sizeof(val));
 263 }
 264
 265 static inline u64 virtio_cread64(struct virtio_device *vdev,
 266                                  unsigned int offset)
 267 {
 268         u64 ret;
 269         vdev->config->get(vdev, offset, &ret, sizeof(ret));
 270         return ret;
 271 }
 272
 273 static inline void virtio_cwrite64(struct virtio_device *vdev,
 274                                    unsigned int offset, u64 val)
 275 {
 276         vdev->config->set(vdev, offset, &val, sizeof(val));
 277 }
 278
 279 /* Conditional config space accessors. */
 280 #define virtio_cread_feature(vdev, fbit, structname, member, ptr)       \
 281         ({                                                              \
 282                 int _r = 0;                                             \
 283                 if (!virtio_has_feature(vdev, fbit))                    \
 284                         _r = -ENOENT;                                   \
 285                 else                                                    \
 286                         virtio_cread((vdev), structname, member, ptr);  \
 287                 _r;                                                     \
 288         })
 289
 290 #endif /* _LINUX_VIRTIO_CONFIG_H */