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 <linux/virtio_byteorder.h>
   8 #include <uapi/linux/virtio_config.h>
   9
  10 /**
  11  * virtio_config_ops - operations for configuring a virtio device
  12  * @get: read the value of a configuration field
  13  *      vdev: the virtio_device
  14  *      offset: the offset of the configuration field
  15  *      buf: the buffer to write the field value into.
  16  *      len: the length of the buffer
  17  * @set: write the value of a configuration field
  18  *      vdev: the virtio_device
  19  *      offset: the offset of the configuration field
  20  *      buf: the buffer to read the field value from.
  21  *      len: the length of the buffer
  22  * @generation: config generation counter
  23  *      vdev: the virtio_device
  24  *      Returns the config generation counter
  25  * @get_status: read the status byte
  26  *      vdev: the virtio_device
  27  *      Returns the status byte
  28  * @set_status: write the status byte
  29  *      vdev: the virtio_device
  30  *      status: the new status byte
  31  * @reset: reset the device
  32  *      vdev: the virtio device
  33  *      After this, status and feature negotiation must be done again
  34  *      Device must not be reset from its vq/config callbacks, or in
  35  *      parallel with being added/removed.
  36  * @find_vqs: find virtqueues and instantiate them.
  37  *      vdev: the virtio_device
  38  *      nvqs: the number of virtqueues to find
  39  *      vqs: on success, includes new virtqueues
  40  *      callbacks: array of callbacks, for each virtqueue
  41  *              include a NULL entry for vqs that do not need a callback
  42  *      names: array of virtqueue names (mainly for debugging)
  43  *              include a NULL entry for vqs unused by driver
  44  *      Returns 0 on success or error status
  45  * @del_vqs: free virtqueues found by find_vqs().
  46  * @get_features: get the array of feature bits for this device.
  47  *      vdev: the virtio_device
  48  *      Returns the first 32 feature bits (all we currently need).
  49  * @finalize_features: confirm what device features we'll be using.
  50  *      vdev: the virtio_device
  51  *      This gives the final feature bits for the device: it can change
  52  *      the dev->feature bits if it wants.
  53  *      Returns 0 on success or error status
  54  * @bus_name: return the bus name associated with the device
  55  *      vdev: the virtio_device
  56  *      This returns a pointer to the bus name a la pci_name from which
  57  *      the caller can then copy.
  58  * @set_vq_affinity: set the affinity for a virtqueue.
  59  */
  60 typedef void vq_callback_t(struct virtqueue *);
  61 struct virtio_config_ops {
  62         void (*get)(struct virtio_device *vdev, unsigned offset,
  63                     void *buf, unsigned len);
  64         void (*set)(struct virtio_device *vdev, unsigned offset,
  65                     const void *buf, unsigned len);
  66         u32 (*generation)(struct virtio_device *vdev);
  67         u8 (*get_status)(struct virtio_device *vdev);
  68         void (*set_status)(struct virtio_device *vdev, u8 status);
  69         void (*reset)(struct virtio_device *vdev);
  70         int (*find_vqs)(struct virtio_device *, unsigned nvqs,
  71                         struct virtqueue *vqs[],
  72                         vq_callback_t *callbacks[],
  73                         const char * const names[]);
  74         void (*del_vqs)(struct virtio_device *);
  75         u64 (*get_features)(struct virtio_device *vdev);
  76         int (*finalize_features)(struct virtio_device *vdev);
  77         const char *(*bus_name)(struct virtio_device *vdev);
  78         int (*set_vq_affinity)(struct virtqueue *vq, int cpu);
  79 };
  80
  81 /* If driver didn't advertise the feature, it will never appear. */
  82 void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
  83                                          unsigned int fbit);
  84
  85 /**
  86  * __virtio_test_bit - helper to test feature bits. For use by transports.
  87  *                     Devices should normally use virtio_has_feature,
  88  *                     which includes more checks.
  89  * @vdev: the device
  90  * @fbit: the feature bit
  91  */
  92 static inline bool __virtio_test_bit(const struct virtio_device *vdev,
  93                                      unsigned int fbit)
  94 {
  95         /* Did you forget to fix assumptions on max features? */
  96         if (__builtin_constant_p(fbit))
  97                 BUILD_BUG_ON(fbit >= 64);
  98         else
  99                 BUG_ON(fbit >= 64);
 100
 101         return vdev->features & BIT_ULL(fbit);
 102 }
 103
 104 /**
 105  * __virtio_set_bit - helper to set feature bits. For use by transports.
 106  * @vdev: the device
 107  * @fbit: the feature bit
 108  */
 109 static inline void __virtio_set_bit(struct virtio_device *vdev,
 110                                     unsigned int fbit)
 111 {
 112         /* Did you forget to fix assumptions on max features? */
 113         if (__builtin_constant_p(fbit))
 114                 BUILD_BUG_ON(fbit >= 64);
 115         else
 116                 BUG_ON(fbit >= 64);
 117
 118         vdev->features |= BIT_ULL(fbit);
 119 }
 120
 121 /**
 122  * __virtio_clear_bit - helper to clear feature bits. For use by transports.
 123  * @vdev: the device
 124  * @fbit: the feature bit
 125  */
 126 static inline void __virtio_clear_bit(struct virtio_device *vdev,
 127                                       unsigned int fbit)
 128 {
 129         /* Did you forget to fix assumptions on max features? */
 130         if (__builtin_constant_p(fbit))
 131                 BUILD_BUG_ON(fbit >= 64);
 132         else
 133                 BUG_ON(fbit >= 64);
 134
 135         vdev->features &= ~BIT_ULL(fbit);
 136 }
 137
 138 /**
 139  * virtio_has_feature - helper to determine if this device has this feature.
 140  * @vdev: the device
 141  * @fbit: the feature bit
 142  */
 143 static inline bool virtio_has_feature(const struct virtio_device *vdev,
 144                                       unsigned int fbit)
 145 {
 146         if (fbit < VIRTIO_TRANSPORT_F_START)
 147                 virtio_check_driver_offered_feature(vdev, fbit);
 148
 149         return __virtio_test_bit(vdev, fbit);
 150 }
 151
 152 static inline
 153 struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev,
 154                                         vq_callback_t *c, const char *n)
 155 {
 156         vq_callback_t *callbacks[] = { c };
 157         const char *names[] = { n };
 158         struct virtqueue *vq;
 159         int err = vdev->config->find_vqs(vdev, 1, &vq, callbacks, names);
 160         if (err < 0)
 161                 return ERR_PTR(err);
 162         return vq;
 163 }
 164
 165 /**
 166  * virtio_device_ready - enable vq use in probe function
 167  * @vdev: the device
 168  *
 169  * Driver must call this to use vqs in the probe function.
 170  *
 171  * Note: vqs are enabled automatically after probe returns.
 172  */
 173 static inline
 174 void virtio_device_ready(struct virtio_device *dev)
 175 {
 176         unsigned status = dev->config->get_status(dev);
 177
 178         BUG_ON(status & VIRTIO_CONFIG_S_DRIVER_OK);
 179         dev->config->set_status(dev, status | VIRTIO_CONFIG_S_DRIVER_OK);
 180 }
 181
 182 static inline
 183 const char *virtio_bus_name(struct virtio_device *vdev)
 184 {
 185         if (!vdev->config->bus_name)
 186                 return "virtio";
 187         return vdev->config->bus_name(vdev);
 188 }
 189
 190 /**
 191  * virtqueue_set_affinity - setting affinity for a virtqueue
 192  * @vq: the virtqueue
 193  * @cpu: the cpu no.
 194  *
 195  * Pay attention the function are best-effort: the affinity hint may not be set
 196  * due to config support, irq type and sharing.
 197  *
 198  */
 199 static inline
 200 int virtqueue_set_affinity(struct virtqueue *vq, int cpu)
 201 {
 202         struct virtio_device *vdev = vq->vdev;
 203         if (vdev->config->set_vq_affinity)
 204                 return vdev->config->set_vq_affinity(vq, cpu);
 205         return 0;
 206 }
 207
 208 static inline bool virtio_is_little_endian(struct virtio_device *vdev)
 209 {
 210         return virtio_has_feature(vdev, VIRTIO_F_VERSION_1) ||
 211                 virtio_legacy_is_little_endian();
 212 }
 213
 214 /* Memory accessors */
 215 static inline u16 virtio16_to_cpu(struct virtio_device *vdev, __virtio16 val)
 216 {
 217         return __virtio16_to_cpu(virtio_is_little_endian(vdev), val);
 218 }
 219
 220 static inline __virtio16 cpu_to_virtio16(struct virtio_device *vdev, u16 val)
 221 {
 222         return __cpu_to_virtio16(virtio_is_little_endian(vdev), val);
 223 }
 224
 225 static inline u32 virtio32_to_cpu(struct virtio_device *vdev, __virtio32 val)
 226 {
 227         return __virtio32_to_cpu(virtio_is_little_endian(vdev), val);
 228 }
 229
 230 static inline __virtio32 cpu_to_virtio32(struct virtio_device *vdev, u32 val)
 231 {
 232         return __cpu_to_virtio32(virtio_is_little_endian(vdev), val);
 233 }
 234
 235 static inline u64 virtio64_to_cpu(struct virtio_device *vdev, __virtio64 val)
 236 {
 237         return __virtio64_to_cpu(virtio_is_little_endian(vdev), val);
 238 }
 239
 240 static inline __virtio64 cpu_to_virtio64(struct virtio_device *vdev, u64 val)
 241 {
 242         return __cpu_to_virtio64(virtio_is_little_endian(vdev), val);
 243 }
 244
 245 /* Config space accessors. */
 246 #define virtio_cread(vdev, structname, member, ptr)                     \
 247         do {                                                            \
 248                 /* Must match the member's type, and be integer */      \
 249                 if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \
 250                         (*ptr) = 1;                                     \
 251                                                                         \
 252                 switch (sizeof(*ptr)) {                                 \
 253                 case 1:                                                 \
 254                         *(ptr) = virtio_cread8(vdev,                    \
 255                                                offsetof(structname, member)); \
 256                         break;                                          \
 257                 case 2:                                                 \
 258                         *(ptr) = virtio_cread16(vdev,                   \
 259                                                 offsetof(structname, member)); \
 260                         break;                                          \
 261                 case 4:                                                 \
 262                         *(ptr) = virtio_cread32(vdev,                   \
 263                                                 offsetof(structname, member)); \
 264                         break;                                          \
 265                 case 8:                                                 \
 266                         *(ptr) = virtio_cread64(vdev,                   \
 267                                                 offsetof(structname, member)); \
 268                         break;                                          \
 269                 default:                                                \
 270                         BUG();                                          \
 271                 }                                                       \
 272         } while(0)
 273
 274 /* Config space accessors. */
 275 #define virtio_cwrite(vdev, structname, member, ptr)                    \
 276         do {                                                            \
 277                 /* Must match the member's type, and be integer */      \
 278                 if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \
 279                         BUG_ON((*ptr) == 1);                            \
 280                                                                         \
 281                 switch (sizeof(*ptr)) {                                 \
 282                 case 1:                                                 \
 283                         virtio_cwrite8(vdev,                            \
 284                                        offsetof(structname, member),    \
 285                                        *(ptr));                         \
 286                         break;                                          \
 287                 case 2:                                                 \
 288                         virtio_cwrite16(vdev,                           \
 289                                         offsetof(structname, member),   \
 290                                         *(ptr));                        \
 291                         break;                                          \
 292                 case 4:                                                 \
 293                         virtio_cwrite32(vdev,                           \
 294                                         offsetof(structname, member),   \
 295                                         *(ptr));                        \
 296                         break;                                          \
 297                 case 8:                                                 \
 298                         virtio_cwrite64(vdev,                           \
 299                                         offsetof(structname, member),   \
 300                                         *(ptr));                        \
 301                         break;                                          \
 302                 default:                                                \
 303                         BUG();                                          \
 304                 }                                                       \
 305         } while(0)
 306
 307 /* Read @count fields, @bytes each. */
 308 static inline void __virtio_cread_many(struct virtio_device *vdev,
 309                                        unsigned int offset,
 310                                        void *buf, size_t count, size_t bytes)
 311 {
 312         u32 old, gen = vdev->config->generation ?
 313                 vdev->config->generation(vdev) : 0;
 314         int i;
 315
 316         do {
 317                 old = gen;
 318
 319                 for (i = 0; i < count; i++)
 320                         vdev->config->get(vdev, offset + bytes * i,
 321                                           buf + i * bytes, bytes);
 322
 323                 gen = vdev->config->generation ?
 324                         vdev->config->generation(vdev) : 0;
 325         } while (gen != old);
 326 }
 327
 328 static inline void virtio_cread_bytes(struct virtio_device *vdev,
 329                                       unsigned int offset,
 330                                       void *buf, size_t len)
 331 {
 332         __virtio_cread_many(vdev, offset, buf, len, 1);
 333 }
 334
 335 static inline u8 virtio_cread8(struct virtio_device *vdev, unsigned int offset)
 336 {
 337         u8 ret;
 338         vdev->config->get(vdev, offset, &ret, sizeof(ret));
 339         return ret;
 340 }
 341
 342 static inline void virtio_cwrite8(struct virtio_device *vdev,
 343                                   unsigned int offset, u8 val)
 344 {
 345         vdev->config->set(vdev, offset, &val, sizeof(val));
 346 }
 347
 348 static inline u16 virtio_cread16(struct virtio_device *vdev,
 349                                  unsigned int offset)
 350 {
 351         u16 ret;
 352         vdev->config->get(vdev, offset, &ret, sizeof(ret));
 353         return virtio16_to_cpu(vdev, (__force __virtio16)ret);
 354 }
 355
 356 static inline void virtio_cwrite16(struct virtio_device *vdev,
 357                                    unsigned int offset, u16 val)
 358 {
 359         val = (__force u16)cpu_to_virtio16(vdev, val);
 360         vdev->config->set(vdev, offset, &val, sizeof(val));
 361 }
 362
 363 static inline u32 virtio_cread32(struct virtio_device *vdev,
 364                                  unsigned int offset)
 365 {
 366         u32 ret;
 367         vdev->config->get(vdev, offset, &ret, sizeof(ret));
 368         return virtio32_to_cpu(vdev, (__force __virtio32)ret);
 369 }
 370
 371 static inline void virtio_cwrite32(struct virtio_device *vdev,
 372                                    unsigned int offset, u32 val)
 373 {
 374         val = (__force u32)cpu_to_virtio32(vdev, val);
 375         vdev->config->set(vdev, offset, &val, sizeof(val));
 376 }
 377
 378 static inline u64 virtio_cread64(struct virtio_device *vdev,
 379                                  unsigned int offset)
 380 {
 381         u64 ret;
 382         __virtio_cread_many(vdev, offset, &ret, 1, sizeof(ret));
 383         return virtio64_to_cpu(vdev, (__force __virtio64)ret);
 384 }
 385
 386 static inline void virtio_cwrite64(struct virtio_device *vdev,
 387                                    unsigned int offset, u64 val)
 388 {
 389         val = (__force u64)cpu_to_virtio64(vdev, val);
 390         vdev->config->set(vdev, offset, &val, sizeof(val));
 391 }
 392
 393 /* Conditional config space accessors. */
 394 #define virtio_cread_feature(vdev, fbit, structname, member, ptr)       \
 395         ({                                                              \
 396                 int _r = 0;                                             \
 397                 if (!virtio_has_feature(vdev, fbit))                    \
 398                         _r = -ENOENT;                                   \
 399                 else                                                    \
 400                         virtio_cread((vdev), structname, member, ptr);  \
 401                 _r;                                                     \
 402         })
 403
 404 #endif /* _LINUX_VIRTIO_CONFIG_H */