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 /**
 153  * virtio_has_iommu_quirk - determine whether this device has the iommu quirk
 154  * @vdev: the device
 155  */
 156 static inline bool virtio_has_iommu_quirk(const struct virtio_device *vdev)
 157 {
 158         /*
 159          * Note the reverse polarity of the quirk feature (compared to most
 160          * other features), this is for compatibility with legacy systems.
 161          */
 162         return !virtio_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM);
 163 }
 164
 165 static inline
 166 struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev,
 167                                         vq_callback_t *c, const char *n)
 168 {
 169         vq_callback_t *callbacks[] = { c };
 170         const char *names[] = { n };
 171         struct virtqueue *vq;
 172         int err = vdev->config->find_vqs(vdev, 1, &vq, callbacks, names);
 173         if (err < 0)
 174                 return ERR_PTR(err);
 175         return vq;
 176 }
 177
 178 /**
 179  * virtio_device_ready - enable vq use in probe function
 180  * @vdev: the device
 181  *
 182  * Driver must call this to use vqs in the probe function.
 183  *
 184  * Note: vqs are enabled automatically after probe returns.
 185  */
 186 static inline
 187 void virtio_device_ready(struct virtio_device *dev)
 188 {
 189         unsigned status = dev->config->get_status(dev);
 190
 191         BUG_ON(status & VIRTIO_CONFIG_S_DRIVER_OK);
 192         dev->config->set_status(dev, status | VIRTIO_CONFIG_S_DRIVER_OK);
 193 }
 194
 195 static inline
 196 const char *virtio_bus_name(struct virtio_device *vdev)
 197 {
 198         if (!vdev->config->bus_name)
 199                 return "virtio";
 200         return vdev->config->bus_name(vdev);
 201 }
 202
 203 /**
 204  * virtqueue_set_affinity - setting affinity for a virtqueue
 205  * @vq: the virtqueue
 206  * @cpu: the cpu no.
 207  *
 208  * Pay attention the function are best-effort: the affinity hint may not be set
 209  * due to config support, irq type and sharing.
 210  *
 211  */
 212 static inline
 213 int virtqueue_set_affinity(struct virtqueue *vq, int cpu)
 214 {
 215         struct virtio_device *vdev = vq->vdev;
 216         if (vdev->config->set_vq_affinity)
 217                 return vdev->config->set_vq_affinity(vq, cpu);
 218         return 0;
 219 }
 220
 221 static inline bool virtio_is_little_endian(struct virtio_device *vdev)
 222 {
 223         return virtio_has_feature(vdev, VIRTIO_F_VERSION_1) ||
 224                 virtio_legacy_is_little_endian();
 225 }
 226
 227 /* Memory accessors */
 228 static inline u16 virtio16_to_cpu(struct virtio_device *vdev, __virtio16 val)
 229 {
 230         return __virtio16_to_cpu(virtio_is_little_endian(vdev), val);
 231 }
 232
 233 static inline __virtio16 cpu_to_virtio16(struct virtio_device *vdev, u16 val)
 234 {
 235         return __cpu_to_virtio16(virtio_is_little_endian(vdev), val);
 236 }
 237
 238 static inline u32 virtio32_to_cpu(struct virtio_device *vdev, __virtio32 val)
 239 {
 240         return __virtio32_to_cpu(virtio_is_little_endian(vdev), val);
 241 }
 242
 243 static inline __virtio32 cpu_to_virtio32(struct virtio_device *vdev, u32 val)
 244 {
 245         return __cpu_to_virtio32(virtio_is_little_endian(vdev), val);
 246 }
 247
 248 static inline u64 virtio64_to_cpu(struct virtio_device *vdev, __virtio64 val)
 249 {
 250         return __virtio64_to_cpu(virtio_is_little_endian(vdev), val);
 251 }
 252
 253 static inline __virtio64 cpu_to_virtio64(struct virtio_device *vdev, u64 val)
 254 {
 255         return __cpu_to_virtio64(virtio_is_little_endian(vdev), val);
 256 }
 257
 258 /* Config space accessors. */
 259 #define virtio_cread(vdev, structname, member, ptr)                     \
 260         do {                                                            \
 261                 /* Must match the member's type, and be integer */      \
 262                 if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \
 263                         (*ptr) = 1;                                     \
 264                                                                         \
 265                 switch (sizeof(*ptr)) {                                 \
 266                 case 1:                                                 \
 267                         *(ptr) = virtio_cread8(vdev,                    \
 268                                                offsetof(structname, member)); \
 269                         break;                                          \
 270                 case 2:                                                 \
 271                         *(ptr) = virtio_cread16(vdev,                   \
 272                                                 offsetof(structname, member)); \
 273                         break;                                          \
 274                 case 4:                                                 \
 275                         *(ptr) = virtio_cread32(vdev,                   \
 276                                                 offsetof(structname, member)); \
 277                         break;                                          \
 278                 case 8:                                                 \
 279                         *(ptr) = virtio_cread64(vdev,                   \
 280                                                 offsetof(structname, member)); \
 281                         break;                                          \
 282                 default:                                                \
 283                         BUG();                                          \
 284                 }                                                       \
 285         } while(0)
 286
 287 /* Config space accessors. */
 288 #define virtio_cwrite(vdev, structname, member, ptr)                    \
 289         do {                                                            \
 290                 /* Must match the member's type, and be integer */      \
 291                 if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \
 292                         BUG_ON((*ptr) == 1);                            \
 293                                                                         \
 294                 switch (sizeof(*ptr)) {                                 \
 295                 case 1:                                                 \
 296                         virtio_cwrite8(vdev,                            \
 297                                        offsetof(structname, member),    \
 298                                        *(ptr));                         \
 299                         break;                                          \
 300                 case 2:                                                 \
 301                         virtio_cwrite16(vdev,                           \
 302                                         offsetof(structname, member),   \
 303                                         *(ptr));                        \
 304                         break;                                          \
 305                 case 4:                                                 \
 306                         virtio_cwrite32(vdev,                           \
 307                                         offsetof(structname, member),   \
 308                                         *(ptr));                        \
 309                         break;                                          \
 310                 case 8:                                                 \
 311                         virtio_cwrite64(vdev,                           \
 312                                         offsetof(structname, member),   \
 313                                         *(ptr));                        \
 314                         break;                                          \
 315                 default:                                                \
 316                         BUG();                                          \
 317                 }                                                       \
 318         } while(0)
 319
 320 /* Read @count fields, @bytes each. */
 321 static inline void __virtio_cread_many(struct virtio_device *vdev,
 322                                        unsigned int offset,
 323                                        void *buf, size_t count, size_t bytes)
 324 {
 325         u32 old, gen = vdev->config->generation ?
 326                 vdev->config->generation(vdev) : 0;
 327         int i;
 328
 329         do {
 330                 old = gen;
 331
 332                 for (i = 0; i < count; i++)
 333                         vdev->config->get(vdev, offset + bytes * i,
 334                                           buf + i * bytes, bytes);
 335
 336                 gen = vdev->config->generation ?
 337                         vdev->config->generation(vdev) : 0;
 338         } while (gen != old);
 339 }
 340
 341 static inline void virtio_cread_bytes(struct virtio_device *vdev,
 342                                       unsigned int offset,
 343                                       void *buf, size_t len)
 344 {
 345         __virtio_cread_many(vdev, offset, buf, len, 1);
 346 }
 347
 348 static inline u8 virtio_cread8(struct virtio_device *vdev, unsigned int offset)
 349 {
 350         u8 ret;
 351         vdev->config->get(vdev, offset, &ret, sizeof(ret));
 352         return ret;
 353 }
 354
 355 static inline void virtio_cwrite8(struct virtio_device *vdev,
 356                                   unsigned int offset, u8 val)
 357 {
 358         vdev->config->set(vdev, offset, &val, sizeof(val));
 359 }
 360
 361 static inline u16 virtio_cread16(struct virtio_device *vdev,
 362                                  unsigned int offset)
 363 {
 364         u16 ret;
 365         vdev->config->get(vdev, offset, &ret, sizeof(ret));
 366         return virtio16_to_cpu(vdev, (__force __virtio16)ret);
 367 }
 368
 369 static inline void virtio_cwrite16(struct virtio_device *vdev,
 370                                    unsigned int offset, u16 val)
 371 {
 372         val = (__force u16)cpu_to_virtio16(vdev, val);
 373         vdev->config->set(vdev, offset, &val, sizeof(val));
 374 }
 375
 376 static inline u32 virtio_cread32(struct virtio_device *vdev,
 377                                  unsigned int offset)
 378 {
 379         u32 ret;
 380         vdev->config->get(vdev, offset, &ret, sizeof(ret));
 381         return virtio32_to_cpu(vdev, (__force __virtio32)ret);
 382 }
 383
 384 static inline void virtio_cwrite32(struct virtio_device *vdev,
 385                                    unsigned int offset, u32 val)
 386 {
 387         val = (__force u32)cpu_to_virtio32(vdev, val);
 388         vdev->config->set(vdev, offset, &val, sizeof(val));
 389 }
 390
 391 static inline u64 virtio_cread64(struct virtio_device *vdev,
 392                                  unsigned int offset)
 393 {
 394         u64 ret;
 395         __virtio_cread_many(vdev, offset, &ret, 1, sizeof(ret));
 396         return virtio64_to_cpu(vdev, (__force __virtio64)ret);
 397 }
 398
 399 static inline void virtio_cwrite64(struct virtio_device *vdev,
 400                                    unsigned int offset, u64 val)
 401 {
 402         val = (__force u64)cpu_to_virtio64(vdev, val);
 403         vdev->config->set(vdev, offset, &val, sizeof(val));
 404 }
 405
 406 /* Conditional config space accessors. */
 407 #define virtio_cread_feature(vdev, fbit, structname, member, ptr)       \
 408         ({                                                              \
 409                 int _r = 0;                                             \
 410                 if (!virtio_has_feature(vdev, fbit))                    \
 411                         _r = -ENOENT;                                   \
 412                 else                                                    \
 413                         virtio_cread((vdev), structname, member, ptr);  \
 414                 _r;                                                     \
 415         })
 416
 417 #endif /* _LINUX_VIRTIO_CONFIG_H */