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 struct irq_affinity;
  11
  12 /**
  13  * virtio_config_ops - operations for configuring a virtio device
  14  * @get: read the value of a configuration field
  15  *      vdev: the virtio_device
  16  *      offset: the offset of the configuration field
  17  *      buf: the buffer to write the field value into.
  18  *      len: the length of the buffer
  19  * @set: write the value of a configuration field
  20  *      vdev: the virtio_device
  21  *      offset: the offset of the configuration field
  22  *      buf: the buffer to read the field value from.
  23  *      len: the length of the buffer
  24  * @generation: config generation counter
  25  *      vdev: the virtio_device
  26  *      Returns the config generation counter
  27  * @get_status: read the status byte
  28  *      vdev: the virtio_device
  29  *      Returns the status byte
  30  * @set_status: write the status byte
  31  *      vdev: the virtio_device
  32  *      status: the new status byte
  33  * @reset: reset the device
  34  *      vdev: the virtio device
  35  *      After this, status and feature negotiation must be done again
  36  *      Device must not be reset from its vq/config callbacks, or in
  37  *      parallel with being added/removed.
  38  * @find_vqs: find virtqueues and instantiate them.
  39  *      vdev: the virtio_device
  40  *      nvqs: the number of virtqueues to find
  41  *      vqs: on success, includes new virtqueues
  42  *      callbacks: array of callbacks, for each virtqueue
  43  *              include a NULL entry for vqs that do not need a callback
  44  *      names: array of virtqueue names (mainly for debugging)
  45  *              include a NULL entry for vqs unused by driver
  46  *      Returns 0 on success or error status
  47  * @del_vqs: free virtqueues found by find_vqs().
  48  * @get_features: get the array of feature bits for this device.
  49  *      vdev: the virtio_device
  50  *      Returns the first 32 feature bits (all we currently need).
  51  * @finalize_features: confirm what device features we'll be using.
  52  *      vdev: the virtio_device
  53  *      This gives the final feature bits for the device: it can change
  54  *      the dev->feature bits if it wants.
  55  *      Returns 0 on success or error status
  56  * @bus_name: return the bus name associated with the device
  57  *      vdev: the virtio_device
  58  *      This returns a pointer to the bus name a la pci_name from which
  59  *      the caller can then copy.
  60  * @set_vq_affinity: set the affinity for a virtqueue.
  61  * @get_vq_affinity: get the affinity for a virtqueue (optional).
  62  */
  63 typedef void vq_callback_t(struct virtqueue *);
  64 struct virtio_config_ops {
  65         void (*get)(struct virtio_device *vdev, unsigned offset,
  66                     void *buf, unsigned len);
  67         void (*set)(struct virtio_device *vdev, unsigned offset,
  68                     const void *buf, unsigned len);
  69         u32 (*generation)(struct virtio_device *vdev);
  70         u8 (*get_status)(struct virtio_device *vdev);
  71         void (*set_status)(struct virtio_device *vdev, u8 status);
  72         void (*reset)(struct virtio_device *vdev);
  73         int (*find_vqs)(struct virtio_device *, unsigned nvqs,
  74                         struct virtqueue *vqs[], vq_callback_t *callbacks[],
  75                         const char * const names[], const bool *ctx,
  76                         struct irq_affinity *desc);
  77         void (*del_vqs)(struct virtio_device *);
  78         u64 (*get_features)(struct virtio_device *vdev);
  79         int (*finalize_features)(struct virtio_device *vdev);
  80         const char *(*bus_name)(struct virtio_device *vdev);
  81         int (*set_vq_affinity)(struct virtqueue *vq, int cpu);
  82         const struct cpumask *(*get_vq_affinity)(struct virtio_device *vdev,
  83                         int index);
  84 };
  85
  86 /* If driver didn't advertise the feature, it will never appear. */
  87 void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
  88                                          unsigned int fbit);
  89
  90 /**
  91  * __virtio_test_bit - helper to test feature bits. For use by transports.
  92  *                     Devices should normally use virtio_has_feature,
  93  *                     which includes more checks.
  94  * @vdev: the device
  95  * @fbit: the feature bit
  96  */
  97 static inline bool __virtio_test_bit(const struct virtio_device *vdev,
  98                                      unsigned int fbit)
  99 {
 100         /* Did you forget to fix assumptions on max features? */
 101         if (__builtin_constant_p(fbit))
 102                 BUILD_BUG_ON(fbit >= 64);
 103         else
 104                 BUG_ON(fbit >= 64);
 105
 106         return vdev->features & BIT_ULL(fbit);
 107 }
 108
 109 /**
 110  * __virtio_set_bit - helper to set feature bits. For use by transports.
 111  * @vdev: the device
 112  * @fbit: the feature bit
 113  */
 114 static inline void __virtio_set_bit(struct virtio_device *vdev,
 115                                     unsigned int fbit)
 116 {
 117         /* Did you forget to fix assumptions on max features? */
 118         if (__builtin_constant_p(fbit))
 119                 BUILD_BUG_ON(fbit >= 64);
 120         else
 121                 BUG_ON(fbit >= 64);
 122
 123         vdev->features |= BIT_ULL(fbit);
 124 }
 125
 126 /**
 127  * __virtio_clear_bit - helper to clear feature bits. For use by transports.
 128  * @vdev: the device
 129  * @fbit: the feature bit
 130  */
 131 static inline void __virtio_clear_bit(struct virtio_device *vdev,
 132                                       unsigned int fbit)
 133 {
 134         /* Did you forget to fix assumptions on max features? */
 135         if (__builtin_constant_p(fbit))
 136                 BUILD_BUG_ON(fbit >= 64);
 137         else
 138                 BUG_ON(fbit >= 64);
 139
 140         vdev->features &= ~BIT_ULL(fbit);
 141 }
 142
 143 /**
 144  * virtio_has_feature - helper to determine if this device has this feature.
 145  * @vdev: the device
 146  * @fbit: the feature bit
 147  */
 148 static inline bool virtio_has_feature(const struct virtio_device *vdev,
 149                                       unsigned int fbit)
 150 {
 151         if (fbit < VIRTIO_TRANSPORT_F_START)
 152                 virtio_check_driver_offered_feature(vdev, fbit);
 153
 154         return __virtio_test_bit(vdev, fbit);
 155 }
 156
 157 /**
 158  * virtio_has_iommu_quirk - determine whether this device has the iommu quirk
 159  * @vdev: the device
 160  */
 161 static inline bool virtio_has_iommu_quirk(const struct virtio_device *vdev)
 162 {
 163         /*
 164          * Note the reverse polarity of the quirk feature (compared to most
 165          * other features), this is for compatibility with legacy systems.
 166          */
 167         return !virtio_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM);
 168 }
 169
 170 static inline
 171 struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev,
 172                                         vq_callback_t *c, const char *n)
 173 {
 174         vq_callback_t *callbacks[] = { c };
 175         const char *names[] = { n };
 176         struct virtqueue *vq;
 177         int err = vdev->config->find_vqs(vdev, 1, &vq, callbacks, names, NULL,
 178                                          NULL);
 179         if (err < 0)
 180                 return ERR_PTR(err);
 181         return vq;
 182 }
 183
 184 static inline
 185 int virtio_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 186                         struct virtqueue *vqs[], vq_callback_t *callbacks[],
 187                         const char * const names[],
 188                         struct irq_affinity *desc)
 189 {
 190         return vdev->config->find_vqs(vdev, nvqs, vqs, callbacks, names, NULL, desc);
 191 }
 192
 193 static inline
 194 int virtio_find_vqs_ctx(struct virtio_device *vdev, unsigned nvqs,
 195                         struct virtqueue *vqs[], vq_callback_t *callbacks[],
 196                         const char * const names[], const bool *ctx,
 197                         struct irq_affinity *desc)
 198 {
 199         return vdev->config->find_vqs(vdev, nvqs, vqs, callbacks, names, ctx,
 200                                       desc);
 201 }
 202
 203 /**
 204  * virtio_device_ready - enable vq use in probe function
 205  * @vdev: the device
 206  *
 207  * Driver must call this to use vqs in the probe function.
 208  *
 209  * Note: vqs are enabled automatically after probe returns.
 210  */
 211 static inline
 212 void virtio_device_ready(struct virtio_device *dev)
 213 {
 214         unsigned status = dev->config->get_status(dev);
 215
 216         BUG_ON(status & VIRTIO_CONFIG_S_DRIVER_OK);
 217         dev->config->set_status(dev, status | VIRTIO_CONFIG_S_DRIVER_OK);
 218 }
 219
 220 static inline
 221 const char *virtio_bus_name(struct virtio_device *vdev)
 222 {
 223         if (!vdev->config->bus_name)
 224                 return "virtio";
 225         return vdev->config->bus_name(vdev);
 226 }
 227
 228 /**
 229  * virtqueue_set_affinity - setting affinity for a virtqueue
 230  * @vq: the virtqueue
 231  * @cpu: the cpu no.
 232  *
 233  * Pay attention the function are best-effort: the affinity hint may not be set
 234  * due to config support, irq type and sharing.
 235  *
 236  */
 237 static inline
 238 int virtqueue_set_affinity(struct virtqueue *vq, int cpu)
 239 {
 240         struct virtio_device *vdev = vq->vdev;
 241         if (vdev->config->set_vq_affinity)
 242                 return vdev->config->set_vq_affinity(vq, cpu);
 243         return 0;
 244 }
 245
 246 static inline bool virtio_is_little_endian(struct virtio_device *vdev)
 247 {
 248         return virtio_has_feature(vdev, VIRTIO_F_VERSION_1) ||
 249                 virtio_legacy_is_little_endian();
 250 }
 251
 252 /* Memory accessors */
 253 static inline u16 virtio16_to_cpu(struct virtio_device *vdev, __virtio16 val)
 254 {
 255         return __virtio16_to_cpu(virtio_is_little_endian(vdev), val);
 256 }
 257
 258 static inline __virtio16 cpu_to_virtio16(struct virtio_device *vdev, u16 val)
 259 {
 260         return __cpu_to_virtio16(virtio_is_little_endian(vdev), val);
 261 }
 262
 263 static inline u32 virtio32_to_cpu(struct virtio_device *vdev, __virtio32 val)
 264 {
 265         return __virtio32_to_cpu(virtio_is_little_endian(vdev), val);
 266 }
 267
 268 static inline __virtio32 cpu_to_virtio32(struct virtio_device *vdev, u32 val)
 269 {
 270         return __cpu_to_virtio32(virtio_is_little_endian(vdev), val);
 271 }
 272
 273 static inline u64 virtio64_to_cpu(struct virtio_device *vdev, __virtio64 val)
 274 {
 275         return __virtio64_to_cpu(virtio_is_little_endian(vdev), val);
 276 }
 277
 278 static inline __virtio64 cpu_to_virtio64(struct virtio_device *vdev, u64 val)
 279 {
 280         return __cpu_to_virtio64(virtio_is_little_endian(vdev), val);
 281 }
 282
 283 /* Config space accessors. */
 284 #define virtio_cread(vdev, structname, member, ptr)                     \
 285         do {                                                            \
 286                 /* Must match the member's type, and be integer */      \
 287                 if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \
 288                         (*ptr) = 1;                                     \
 289                                                                         \
 290                 switch (sizeof(*ptr)) {                                 \
 291                 case 1:                                                 \
 292                         *(ptr) = virtio_cread8(vdev,                    \
 293                                                offsetof(structname, member)); \
 294                         break;                                          \
 295                 case 2:                                                 \
 296                         *(ptr) = virtio_cread16(vdev,                   \
 297                                                 offsetof(structname, member)); \
 298                         break;                                          \
 299                 case 4:                                                 \
 300                         *(ptr) = virtio_cread32(vdev,                   \
 301                                                 offsetof(structname, member)); \
 302                         break;                                          \
 303                 case 8:                                                 \
 304                         *(ptr) = virtio_cread64(vdev,                   \
 305                                                 offsetof(structname, member)); \
 306                         break;                                          \
 307                 default:                                                \
 308                         BUG();                                          \
 309                 }                                                       \
 310         } while(0)
 311
 312 /* Config space accessors. */
 313 #define virtio_cwrite(vdev, structname, member, ptr)                    \
 314         do {                                                            \
 315                 /* Must match the member's type, and be integer */      \
 316                 if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \
 317                         BUG_ON((*ptr) == 1);                            \
 318                                                                         \
 319                 switch (sizeof(*ptr)) {                                 \
 320                 case 1:                                                 \
 321                         virtio_cwrite8(vdev,                            \
 322                                        offsetof(structname, member),    \
 323                                        *(ptr));                         \
 324                         break;                                          \
 325                 case 2:                                                 \
 326                         virtio_cwrite16(vdev,                           \
 327                                         offsetof(structname, member),   \
 328                                         *(ptr));                        \
 329                         break;                                          \
 330                 case 4:                                                 \
 331                         virtio_cwrite32(vdev,                           \
 332                                         offsetof(structname, member),   \
 333                                         *(ptr));                        \
 334                         break;                                          \
 335                 case 8:                                                 \
 336                         virtio_cwrite64(vdev,                           \
 337                                         offsetof(structname, member),   \
 338                                         *(ptr));                        \
 339                         break;                                          \
 340                 default:                                                \
 341                         BUG();                                          \
 342                 }                                                       \
 343         } while(0)
 344
 345 /* Read @count fields, @bytes each. */
 346 static inline void __virtio_cread_many(struct virtio_device *vdev,
 347                                        unsigned int offset,
 348                                        void *buf, size_t count, size_t bytes)
 349 {
 350         u32 old, gen = vdev->config->generation ?
 351                 vdev->config->generation(vdev) : 0;
 352         int i;
 353
 354         do {
 355                 old = gen;
 356
 357                 for (i = 0; i < count; i++)
 358                         vdev->config->get(vdev, offset + bytes * i,
 359                                           buf + i * bytes, bytes);
 360
 361                 gen = vdev->config->generation ?
 362                         vdev->config->generation(vdev) : 0;
 363         } while (gen != old);
 364 }
 365
 366 static inline void virtio_cread_bytes(struct virtio_device *vdev,
 367                                       unsigned int offset,
 368                                       void *buf, size_t len)
 369 {
 370         __virtio_cread_many(vdev, offset, buf, len, 1);
 371 }
 372
 373 static inline u8 virtio_cread8(struct virtio_device *vdev, unsigned int offset)
 374 {
 375         u8 ret;
 376         vdev->config->get(vdev, offset, &ret, sizeof(ret));
 377         return ret;
 378 }
 379
 380 static inline void virtio_cwrite8(struct virtio_device *vdev,
 381                                   unsigned int offset, u8 val)
 382 {
 383         vdev->config->set(vdev, offset, &val, sizeof(val));
 384 }
 385
 386 static inline u16 virtio_cread16(struct virtio_device *vdev,
 387                                  unsigned int offset)
 388 {
 389         u16 ret;
 390         vdev->config->get(vdev, offset, &ret, sizeof(ret));
 391         return virtio16_to_cpu(vdev, (__force __virtio16)ret);
 392 }
 393
 394 static inline void virtio_cwrite16(struct virtio_device *vdev,
 395                                    unsigned int offset, u16 val)
 396 {
 397         val = (__force u16)cpu_to_virtio16(vdev, val);
 398         vdev->config->set(vdev, offset, &val, sizeof(val));
 399 }
 400
 401 static inline u32 virtio_cread32(struct virtio_device *vdev,
 402                                  unsigned int offset)
 403 {
 404         u32 ret;
 405         vdev->config->get(vdev, offset, &ret, sizeof(ret));
 406         return virtio32_to_cpu(vdev, (__force __virtio32)ret);
 407 }
 408
 409 static inline void virtio_cwrite32(struct virtio_device *vdev,
 410                                    unsigned int offset, u32 val)
 411 {
 412         val = (__force u32)cpu_to_virtio32(vdev, val);
 413         vdev->config->set(vdev, offset, &val, sizeof(val));
 414 }
 415
 416 static inline u64 virtio_cread64(struct virtio_device *vdev,
 417                                  unsigned int offset)
 418 {
 419         u64 ret;
 420         __virtio_cread_many(vdev, offset, &ret, 1, sizeof(ret));
 421         return virtio64_to_cpu(vdev, (__force __virtio64)ret);
 422 }
 423
 424 static inline void virtio_cwrite64(struct virtio_device *vdev,
 425                                    unsigned int offset, u64 val)
 426 {
 427         val = (__force u64)cpu_to_virtio64(vdev, val);
 428         vdev->config->set(vdev, offset, &val, sizeof(val));
 429 }
 430
 431 /* Conditional config space accessors. */
 432 #define virtio_cread_feature(vdev, fbit, structname, member, ptr)       \
 433         ({                                                              \
 434                 int _r = 0;                                             \
 435                 if (!virtio_has_feature(vdev, fbit))                    \
 436                         _r = -ENOENT;                                   \
 437                 else                                                    \
 438                         virtio_cread((vdev), structname, member, ptr);  \
 439                 _r;                                                     \
 440         })
 441
 442 #endif /* _LINUX_VIRTIO_CONFIG_H */