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[], struct irq_affinity *desc);
  76         void (*del_vqs)(struct virtio_device *);
  77         u64 (*get_features)(struct virtio_device *vdev);
  78         int (*finalize_features)(struct virtio_device *vdev);
  79         const char *(*bus_name)(struct virtio_device *vdev);
  80         int (*set_vq_affinity)(struct virtqueue *vq, int cpu);
  81         const struct cpumask *(*get_vq_affinity)(struct virtio_device *vdev,
  82                         int index);
  83 };
  84
  85 /* If driver didn't advertise the feature, it will never appear. */
  86 void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
  87                                          unsigned int fbit);
  88
  89 /**
  90  * __virtio_test_bit - helper to test feature bits. For use by transports.
  91  *                     Devices should normally use virtio_has_feature,
  92  *                     which includes more checks.
  93  * @vdev: the device
  94  * @fbit: the feature bit
  95  */
  96 static inline bool __virtio_test_bit(const struct virtio_device *vdev,
  97                                      unsigned int fbit)
  98 {
  99         /* Did you forget to fix assumptions on max features? */
 100         if (__builtin_constant_p(fbit))
 101                 BUILD_BUG_ON(fbit >= 64);
 102         else
 103                 BUG_ON(fbit >= 64);
 104
 105         return vdev->features & BIT_ULL(fbit);
 106 }
 107
 108 /**
 109  * __virtio_set_bit - helper to set feature bits. For use by transports.
 110  * @vdev: the device
 111  * @fbit: the feature bit
 112  */
 113 static inline void __virtio_set_bit(struct virtio_device *vdev,
 114                                     unsigned int fbit)
 115 {
 116         /* Did you forget to fix assumptions on max features? */
 117         if (__builtin_constant_p(fbit))
 118                 BUILD_BUG_ON(fbit >= 64);
 119         else
 120                 BUG_ON(fbit >= 64);
 121
 122         vdev->features |= BIT_ULL(fbit);
 123 }
 124
 125 /**
 126  * __virtio_clear_bit - helper to clear feature bits. For use by transports.
 127  * @vdev: the device
 128  * @fbit: the feature bit
 129  */
 130 static inline void __virtio_clear_bit(struct virtio_device *vdev,
 131                                       unsigned int fbit)
 132 {
 133         /* Did you forget to fix assumptions on max features? */
 134         if (__builtin_constant_p(fbit))
 135                 BUILD_BUG_ON(fbit >= 64);
 136         else
 137                 BUG_ON(fbit >= 64);
 138
 139         vdev->features &= ~BIT_ULL(fbit);
 140 }
 141
 142 /**
 143  * virtio_has_feature - helper to determine if this device has this feature.
 144  * @vdev: the device
 145  * @fbit: the feature bit
 146  */
 147 static inline bool virtio_has_feature(const struct virtio_device *vdev,
 148                                       unsigned int fbit)
 149 {
 150         if (fbit < VIRTIO_TRANSPORT_F_START)
 151                 virtio_check_driver_offered_feature(vdev, fbit);
 152
 153         return __virtio_test_bit(vdev, fbit);
 154 }
 155
 156 /**
 157  * virtio_has_iommu_quirk - determine whether this device has the iommu quirk
 158  * @vdev: the device
 159  */
 160 static inline bool virtio_has_iommu_quirk(const struct virtio_device *vdev)
 161 {
 162         /*
 163          * Note the reverse polarity of the quirk feature (compared to most
 164          * other features), this is for compatibility with legacy systems.
 165          */
 166         return !virtio_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM);
 167 }
 168
 169 static inline
 170 struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev,
 171                                         vq_callback_t *c, const char *n)
 172 {
 173         vq_callback_t *callbacks[] = { c };
 174         const char *names[] = { n };
 175         struct virtqueue *vq;
 176         int err = vdev->config->find_vqs(vdev, 1, &vq, callbacks, names, NULL);
 177         if (err < 0)
 178                 return ERR_PTR(err);
 179         return vq;
 180 }
 181
 182 /**
 183  * virtio_device_ready - enable vq use in probe function
 184  * @vdev: the device
 185  *
 186  * Driver must call this to use vqs in the probe function.
 187  *
 188  * Note: vqs are enabled automatically after probe returns.
 189  */
 190 static inline
 191 void virtio_device_ready(struct virtio_device *dev)
 192 {
 193         unsigned status = dev->config->get_status(dev);
 194
 195         BUG_ON(status & VIRTIO_CONFIG_S_DRIVER_OK);
 196         dev->config->set_status(dev, status | VIRTIO_CONFIG_S_DRIVER_OK);
 197 }
 198
 199 static inline
 200 const char *virtio_bus_name(struct virtio_device *vdev)
 201 {
 202         if (!vdev->config->bus_name)
 203                 return "virtio";
 204         return vdev->config->bus_name(vdev);
 205 }
 206
 207 /**
 208  * virtqueue_set_affinity - setting affinity for a virtqueue
 209  * @vq: the virtqueue
 210  * @cpu: the cpu no.
 211  *
 212  * Pay attention the function are best-effort: the affinity hint may not be set
 213  * due to config support, irq type and sharing.
 214  *
 215  */
 216 static inline
 217 int virtqueue_set_affinity(struct virtqueue *vq, int cpu)
 218 {
 219         struct virtio_device *vdev = vq->vdev;
 220         if (vdev->config->set_vq_affinity)
 221                 return vdev->config->set_vq_affinity(vq, cpu);
 222         return 0;
 223 }
 224
 225 static inline bool virtio_is_little_endian(struct virtio_device *vdev)
 226 {
 227         return virtio_has_feature(vdev, VIRTIO_F_VERSION_1) ||
 228                 virtio_legacy_is_little_endian();
 229 }
 230
 231 /* Memory accessors */
 232 static inline u16 virtio16_to_cpu(struct virtio_device *vdev, __virtio16 val)
 233 {
 234         return __virtio16_to_cpu(virtio_is_little_endian(vdev), val);
 235 }
 236
 237 static inline __virtio16 cpu_to_virtio16(struct virtio_device *vdev, u16 val)
 238 {
 239         return __cpu_to_virtio16(virtio_is_little_endian(vdev), val);
 240 }
 241
 242 static inline u32 virtio32_to_cpu(struct virtio_device *vdev, __virtio32 val)
 243 {
 244         return __virtio32_to_cpu(virtio_is_little_endian(vdev), val);
 245 }
 246
 247 static inline __virtio32 cpu_to_virtio32(struct virtio_device *vdev, u32 val)
 248 {
 249         return __cpu_to_virtio32(virtio_is_little_endian(vdev), val);
 250 }
 251
 252 static inline u64 virtio64_to_cpu(struct virtio_device *vdev, __virtio64 val)
 253 {
 254         return __virtio64_to_cpu(virtio_is_little_endian(vdev), val);
 255 }
 256
 257 static inline __virtio64 cpu_to_virtio64(struct virtio_device *vdev, u64 val)
 258 {
 259         return __cpu_to_virtio64(virtio_is_little_endian(vdev), val);
 260 }
 261
 262 /* Config space accessors. */
 263 #define virtio_cread(vdev, structname, member, ptr)                     \
 264         do {                                                            \
 265                 /* Must match the member's type, and be integer */      \
 266                 if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \
 267                         (*ptr) = 1;                                     \
 268                                                                         \
 269                 switch (sizeof(*ptr)) {                                 \
 270                 case 1:                                                 \
 271                         *(ptr) = virtio_cread8(vdev,                    \
 272                                                offsetof(structname, member)); \
 273                         break;                                          \
 274                 case 2:                                                 \
 275                         *(ptr) = virtio_cread16(vdev,                   \
 276                                                 offsetof(structname, member)); \
 277                         break;                                          \
 278                 case 4:                                                 \
 279                         *(ptr) = virtio_cread32(vdev,                   \
 280                                                 offsetof(structname, member)); \
 281                         break;                                          \
 282                 case 8:                                                 \
 283                         *(ptr) = virtio_cread64(vdev,                   \
 284                                                 offsetof(structname, member)); \
 285                         break;                                          \
 286                 default:                                                \
 287                         BUG();                                          \
 288                 }                                                       \
 289         } while(0)
 290
 291 /* Config space accessors. */
 292 #define virtio_cwrite(vdev, structname, member, ptr)                    \
 293         do {                                                            \
 294                 /* Must match the member's type, and be integer */      \
 295                 if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \
 296                         BUG_ON((*ptr) == 1);                            \
 297                                                                         \
 298                 switch (sizeof(*ptr)) {                                 \
 299                 case 1:                                                 \
 300                         virtio_cwrite8(vdev,                            \
 301                                        offsetof(structname, member),    \
 302                                        *(ptr));                         \
 303                         break;                                          \
 304                 case 2:                                                 \
 305                         virtio_cwrite16(vdev,                           \
 306                                         offsetof(structname, member),   \
 307                                         *(ptr));                        \
 308                         break;                                          \
 309                 case 4:                                                 \
 310                         virtio_cwrite32(vdev,                           \
 311                                         offsetof(structname, member),   \
 312                                         *(ptr));                        \
 313                         break;                                          \
 314                 case 8:                                                 \
 315                         virtio_cwrite64(vdev,                           \
 316                                         offsetof(structname, member),   \
 317                                         *(ptr));                        \
 318                         break;                                          \
 319                 default:                                                \
 320                         BUG();                                          \
 321                 }                                                       \
 322         } while(0)
 323
 324 /* Read @count fields, @bytes each. */
 325 static inline void __virtio_cread_many(struct virtio_device *vdev,
 326                                        unsigned int offset,
 327                                        void *buf, size_t count, size_t bytes)
 328 {
 329         u32 old, gen = vdev->config->generation ?
 330                 vdev->config->generation(vdev) : 0;
 331         int i;
 332
 333         do {
 334                 old = gen;
 335
 336                 for (i = 0; i < count; i++)
 337                         vdev->config->get(vdev, offset + bytes * i,
 338                                           buf + i * bytes, bytes);
 339
 340                 gen = vdev->config->generation ?
 341                         vdev->config->generation(vdev) : 0;
 342         } while (gen != old);
 343 }
 344
 345 static inline void virtio_cread_bytes(struct virtio_device *vdev,
 346                                       unsigned int offset,
 347                                       void *buf, size_t len)
 348 {
 349         __virtio_cread_many(vdev, offset, buf, len, 1);
 350 }
 351
 352 static inline u8 virtio_cread8(struct virtio_device *vdev, unsigned int offset)
 353 {
 354         u8 ret;
 355         vdev->config->get(vdev, offset, &ret, sizeof(ret));
 356         return ret;
 357 }
 358
 359 static inline void virtio_cwrite8(struct virtio_device *vdev,
 360                                   unsigned int offset, u8 val)
 361 {
 362         vdev->config->set(vdev, offset, &val, sizeof(val));
 363 }
 364
 365 static inline u16 virtio_cread16(struct virtio_device *vdev,
 366                                  unsigned int offset)
 367 {
 368         u16 ret;
 369         vdev->config->get(vdev, offset, &ret, sizeof(ret));
 370         return virtio16_to_cpu(vdev, (__force __virtio16)ret);
 371 }
 372
 373 static inline void virtio_cwrite16(struct virtio_device *vdev,
 374                                    unsigned int offset, u16 val)
 375 {
 376         val = (__force u16)cpu_to_virtio16(vdev, val);
 377         vdev->config->set(vdev, offset, &val, sizeof(val));
 378 }
 379
 380 static inline u32 virtio_cread32(struct virtio_device *vdev,
 381                                  unsigned int offset)
 382 {
 383         u32 ret;
 384         vdev->config->get(vdev, offset, &ret, sizeof(ret));
 385         return virtio32_to_cpu(vdev, (__force __virtio32)ret);
 386 }
 387
 388 static inline void virtio_cwrite32(struct virtio_device *vdev,
 389                                    unsigned int offset, u32 val)
 390 {
 391         val = (__force u32)cpu_to_virtio32(vdev, val);
 392         vdev->config->set(vdev, offset, &val, sizeof(val));
 393 }
 394
 395 static inline u64 virtio_cread64(struct virtio_device *vdev,
 396                                  unsigned int offset)
 397 {
 398         u64 ret;
 399         __virtio_cread_many(vdev, offset, &ret, 1, sizeof(ret));
 400         return virtio64_to_cpu(vdev, (__force __virtio64)ret);
 401 }
 402
 403 static inline void virtio_cwrite64(struct virtio_device *vdev,
 404                                    unsigned int offset, u64 val)
 405 {
 406         val = (__force u64)cpu_to_virtio64(vdev, val);
 407         vdev->config->set(vdev, offset, &val, sizeof(val));
 408 }
 409
 410 /* Conditional config space accessors. */
 411 #define virtio_cread_feature(vdev, fbit, structname, member, ptr)       \
 412         ({                                                              \
 413                 int _r = 0;                                             \
 414                 if (!virtio_has_feature(vdev, fbit))                    \
 415                         _r = -ENOENT;                                   \
 416                 else                                                    \
 417                         virtio_cread((vdev), structname, member, ptr);  \
 418                 _r;                                                     \
 419         })
 420
 421 #endif /* _LINUX_VIRTIO_CONFIG_H */