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         u64 (*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_test_bit - helper to test feature bits. For use by transports.
  81  *                     Devices should normally use virtio_has_feature,
  82  *                     which includes more checks.
  83  * @vdev: the device
  84  * @fbit: the feature bit
  85  */
  86 static inline bool __virtio_test_bit(const struct virtio_device *vdev,
  87                                      unsigned int fbit)
  88 {
  89         /* Did you forget to fix assumptions on max features? */
  90         if (__builtin_constant_p(fbit))
  91                 BUILD_BUG_ON(fbit >= 64);
  92         else
  93                 BUG_ON(fbit >= 64);
  94
  95         return vdev->features & BIT_ULL(fbit);
  96 }
  97
  98 /**
  99  * __virtio_set_bit - helper to set feature bits. For use by transports.
 100  * @vdev: the device
 101  * @fbit: the feature bit
 102  */
 103 static inline void __virtio_set_bit(struct virtio_device *vdev,
 104                                     unsigned int fbit)
 105 {
 106         /* Did you forget to fix assumptions on max features? */
 107         if (__builtin_constant_p(fbit))
 108                 BUILD_BUG_ON(fbit >= 64);
 109         else
 110                 BUG_ON(fbit >= 64);
 111
 112         vdev->features |= BIT_ULL(fbit);
 113 }
 114
 115 /**
 116  * __virtio_clear_bit - helper to clear feature bits. For use by transports.
 117  * @vdev: the device
 118  * @fbit: the feature bit
 119  */
 120 static inline void __virtio_clear_bit(struct virtio_device *vdev,
 121                                       unsigned int fbit)
 122 {
 123         /* Did you forget to fix assumptions on max features? */
 124         if (__builtin_constant_p(fbit))
 125                 BUILD_BUG_ON(fbit >= 64);
 126         else
 127                 BUG_ON(fbit >= 64);
 128
 129         vdev->features &= ~BIT_ULL(fbit);
 130 }
 131
 132 /**
 133  * virtio_has_feature - helper to determine if this device has this feature.
 134  * @vdev: the device
 135  * @fbit: the feature bit
 136  */
 137 static inline bool virtio_has_feature(const struct virtio_device *vdev,
 138                                       unsigned int fbit)
 139 {
 140         if (fbit < VIRTIO_TRANSPORT_F_START)
 141                 virtio_check_driver_offered_feature(vdev, fbit);
 142
 143         return __virtio_test_bit(vdev, fbit);
 144 }
 145
 146 static inline
 147 struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev,
 148                                         vq_callback_t *c, const char *n)
 149 {
 150         vq_callback_t *callbacks[] = { c };
 151         const char *names[] = { n };
 152         struct virtqueue *vq;
 153         int err = vdev->config->find_vqs(vdev, 1, &vq, callbacks, names);
 154         if (err < 0)
 155                 return ERR_PTR(err);
 156         return vq;
 157 }
 158
 159 /**
 160  * virtio_device_ready - enable vq use in probe function
 161  * @vdev: the device
 162  *
 163  * Driver must call this to use vqs in the probe function.
 164  *
 165  * Note: vqs are enabled automatically after probe returns.
 166  */
 167 static inline
 168 void virtio_device_ready(struct virtio_device *dev)
 169 {
 170         unsigned status = dev->config->get_status(dev);
 171
 172         BUG_ON(status & VIRTIO_CONFIG_S_DRIVER_OK);
 173         dev->config->set_status(dev, status | VIRTIO_CONFIG_S_DRIVER_OK);
 174 }
 175
 176 static inline
 177 const char *virtio_bus_name(struct virtio_device *vdev)
 178 {
 179         if (!vdev->config->bus_name)
 180                 return "virtio";
 181         return vdev->config->bus_name(vdev);
 182 }
 183
 184 /**
 185  * virtqueue_set_affinity - setting affinity for a virtqueue
 186  * @vq: the virtqueue
 187  * @cpu: the cpu no.
 188  *
 189  * Pay attention the function are best-effort: the affinity hint may not be set
 190  * due to config support, irq type and sharing.
 191  *
 192  */
 193 static inline
 194 int virtqueue_set_affinity(struct virtqueue *vq, int cpu)
 195 {
 196         struct virtio_device *vdev = vq->vdev;
 197         if (vdev->config->set_vq_affinity)
 198                 return vdev->config->set_vq_affinity(vq, cpu);
 199         return 0;
 200 }
 201
 202 /* Config space accessors. */
 203 #define virtio_cread(vdev, structname, member, ptr)                     \
 204         do {                                                            \
 205                 /* Must match the member's type, and be integer */      \
 206                 if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \
 207                         (*ptr) = 1;                                     \
 208                                                                         \
 209                 switch (sizeof(*ptr)) {                                 \
 210                 case 1:                                                 \
 211                         *(ptr) = virtio_cread8(vdev,                    \
 212                                                offsetof(structname, member)); \
 213                         break;                                          \
 214                 case 2:                                                 \
 215                         *(ptr) = virtio_cread16(vdev,                   \
 216                                                 offsetof(structname, member)); \
 217                         break;                                          \
 218                 case 4:                                                 \
 219                         *(ptr) = virtio_cread32(vdev,                   \
 220                                                 offsetof(structname, member)); \
 221                         break;                                          \
 222                 case 8:                                                 \
 223                         *(ptr) = virtio_cread64(vdev,                   \
 224                                                 offsetof(structname, member)); \
 225                         break;                                          \
 226                 default:                                                \
 227                         BUG();                                          \
 228                 }                                                       \
 229         } while(0)
 230
 231 /* Config space accessors. */
 232 #define virtio_cwrite(vdev, structname, member, ptr)                    \
 233         do {                                                            \
 234                 /* Must match the member's type, and be integer */      \
 235                 if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \
 236                         BUG_ON((*ptr) == 1);                            \
 237                                                                         \
 238                 switch (sizeof(*ptr)) {                                 \
 239                 case 1:                                                 \
 240                         virtio_cwrite8(vdev,                            \
 241                                        offsetof(structname, member),    \
 242                                        *(ptr));                         \
 243                         break;                                          \
 244                 case 2:                                                 \
 245                         virtio_cwrite16(vdev,                           \
 246                                         offsetof(structname, member),   \
 247                                         *(ptr));                        \
 248                         break;                                          \
 249                 case 4:                                                 \
 250                         virtio_cwrite32(vdev,                           \
 251                                         offsetof(structname, member),   \
 252                                         *(ptr));                        \
 253                         break;                                          \
 254                 case 8:                                                 \
 255                         virtio_cwrite64(vdev,                           \
 256                                         offsetof(structname, member),   \
 257                                         *(ptr));                        \
 258                         break;                                          \
 259                 default:                                                \
 260                         BUG();                                          \
 261                 }                                                       \
 262         } while(0)
 263
 264 static inline u8 virtio_cread8(struct virtio_device *vdev, unsigned int offset)
 265 {
 266         u8 ret;
 267         vdev->config->get(vdev, offset, &ret, sizeof(ret));
 268         return ret;
 269 }
 270
 271 static inline void virtio_cread_bytes(struct virtio_device *vdev,
 272                                       unsigned int offset,
 273                                       void *buf, size_t len)
 274 {
 275         vdev->config->get(vdev, offset, buf, len);
 276 }
 277
 278 static inline void virtio_cwrite8(struct virtio_device *vdev,
 279                                   unsigned int offset, u8 val)
 280 {
 281         vdev->config->set(vdev, offset, &val, sizeof(val));
 282 }
 283
 284 static inline u16 virtio_cread16(struct virtio_device *vdev,
 285                                  unsigned int offset)
 286 {
 287         u16 ret;
 288         vdev->config->get(vdev, offset, &ret, sizeof(ret));
 289         return ret;
 290 }
 291
 292 static inline void virtio_cwrite16(struct virtio_device *vdev,
 293                                    unsigned int offset, u16 val)
 294 {
 295         vdev->config->set(vdev, offset, &val, sizeof(val));
 296 }
 297
 298 static inline u32 virtio_cread32(struct virtio_device *vdev,
 299                                  unsigned int offset)
 300 {
 301         u32 ret;
 302         vdev->config->get(vdev, offset, &ret, sizeof(ret));
 303         return ret;
 304 }
 305
 306 static inline void virtio_cwrite32(struct virtio_device *vdev,
 307                                    unsigned int offset, u32 val)
 308 {
 309         vdev->config->set(vdev, offset, &val, sizeof(val));
 310 }
 311
 312 static inline u64 virtio_cread64(struct virtio_device *vdev,
 313                                  unsigned int offset)
 314 {
 315         u64 ret;
 316         vdev->config->get(vdev, offset, &ret, sizeof(ret));
 317         return ret;
 318 }
 319
 320 static inline void virtio_cwrite64(struct virtio_device *vdev,
 321                                    unsigned int offset, u64 val)
 322 {
 323         vdev->config->set(vdev, offset, &val, sizeof(val));
 324 }
 325
 326 /* Conditional config space accessors. */
 327 #define virtio_cread_feature(vdev, fbit, structname, member, ptr)       \
 328         ({                                                              \
 329                 int _r = 0;                                             \
 330                 if (!virtio_has_feature(vdev, fbit))                    \
 331                         _r = -ENOENT;                                   \
 332                 else                                                    \
 333                         virtio_cread((vdev), structname, member, ptr);  \
 334                 _r;                                                     \
 335         })
 336
 337 #endif /* _LINUX_VIRTIO_CONFIG_H */