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