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 <uapi/linux/virtio_config.h>
   8
   9 /**
  10  * virtio_config_ops - operations for configuring a virtio device
  11  * @get: read the value of a configuration field
  12  *      vdev: the virtio_device
  13  *      offset: the offset of the configuration field
  14  *      buf: the buffer to write the field value into.
  15  *      len: the length of the buffer
  16  * @set: write the value of a configuration field
  17  *      vdev: the virtio_device
  18  *      offset: the offset of the configuration field
  19  *      buf: the buffer to read the field value from.
  20  *      len: the length of the buffer
  21  * @get_status: read the status byte
  22  *      vdev: the virtio_device
  23  *      Returns the status byte
  24  * @set_status: write the status byte
  25  *      vdev: the virtio_device
  26  *      status: the new status byte
  27  * @reset: reset the device
  28  *      vdev: the virtio device
  29  *      After this, status and feature negotiation must be done again
  30  *      Device must not be reset from its vq/config callbacks, or in
  31  *      parallel with being added/removed.
  32  * @find_vqs: find virtqueues and instantiate them.
  33  *      vdev: the virtio_device
  34  *      nvqs: the number of virtqueues to find
  35  *      vqs: on success, includes new virtqueues
  36  *      callbacks: array of callbacks, for each virtqueue
  37  *              include a NULL entry for vqs that do not need a callback
  38  *      names: array of virtqueue names (mainly for debugging)
  39  *              include a NULL entry for vqs unused by driver
  40  *      Returns 0 on success or error status
  41  * @del_vqs: free virtqueues found by find_vqs().
  42  * @get_features: get the array of feature bits for this device.
  43  *      vdev: the virtio_device
  44  *      Returns the first 32 feature bits (all we currently need).
  45  * @finalize_features: confirm what device features we'll be using.
  46  *      vdev: the virtio_device
  47  *      This gives the final feature bits for the device: it can change
  48  *      the dev->feature bits if it wants.
  49  * @bus_name: return the bus name associated with the device
  50  *      vdev: the virtio_device
  51  *      This returns a pointer to the bus name a la pci_name from which
  52  *      the caller can then copy.
  53  * @set_vq_affinity: set the affinity for a virtqueue.
  54  */
  55 typedef void vq_callback_t(struct virtqueue *);
  56 struct virtio_config_ops {
  57         void (*get)(struct virtio_device *vdev, unsigned offset,
  58                     void *buf, unsigned len);
  59         void (*set)(struct virtio_device *vdev, unsigned offset,
  60                     const void *buf, unsigned len);
  61         u8 (*get_status)(struct virtio_device *vdev);
  62         void (*set_status)(struct virtio_device *vdev, u8 status);
  63         void (*reset)(struct virtio_device *vdev);
  64         int (*find_vqs)(struct virtio_device *, unsigned nvqs,
  65                         struct virtqueue *vqs[],
  66                         vq_callback_t *callbacks[],
  67                         const char *names[]);
  68         void (*del_vqs)(struct virtio_device *);
  69         u32 (*get_features)(struct virtio_device *vdev);
  70         void (*finalize_features)(struct virtio_device *vdev);
  71         const char *(*bus_name)(struct virtio_device *vdev);
  72         int (*set_vq_affinity)(struct virtqueue *vq, int cpu);
  73 };
  74
  75 /* If driver didn't advertise the feature, it will never appear. */
  76 void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
  77                                          unsigned int fbit);
  78
  79 /**
  80  * virtio_has_feature - helper to determine if this device has this feature.
  81  * @vdev: the device
  82  * @fbit: the feature bit
  83  */
  84 static inline bool virtio_has_feature(const struct virtio_device *vdev,
  85                                       unsigned int fbit)
  86 {
  87         /* Did you forget to fix assumptions on max features? */
  88         if (__builtin_constant_p(fbit))
  89                 BUILD_BUG_ON(fbit >= 32);
  90         else
  91                 BUG_ON(fbit >= 32);
  92
  93         if (fbit < VIRTIO_TRANSPORT_F_START)
  94                 virtio_check_driver_offered_feature(vdev, fbit);
  95
  96         return test_bit(fbit, vdev->features);
  97 }
  98
  99 static inline
 100 struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev,
 101                                         vq_callback_t *c, const char *n)
 102 {
 103         vq_callback_t *callbacks[] = { c };
 104         const char *names[] = { n };
 105         struct virtqueue *vq;
 106         int err = vdev->config->find_vqs(vdev, 1, &vq, callbacks, names);
 107         if (err < 0)
 108                 return ERR_PTR(err);
 109         return vq;
 110 }
 111
 112 static inline
 113 const char *virtio_bus_name(struct virtio_device *vdev)
 114 {
 115         if (!vdev->config->bus_name)
 116                 return "virtio";
 117         return vdev->config->bus_name(vdev);
 118 }
 119
 120 /**
 121  * virtqueue_set_affinity - setting affinity for a virtqueue
 122  * @vq: the virtqueue
 123  * @cpu: the cpu no.
 124  *
 125  * Pay attention the function are best-effort: the affinity hint may not be set
 126  * due to config support, irq type and sharing.
 127  *
 128  */
 129 static inline
 130 int virtqueue_set_affinity(struct virtqueue *vq, int cpu)
 131 {
 132         struct virtio_device *vdev = vq->vdev;
 133         if (vdev->config->set_vq_affinity)
 134                 return vdev->config->set_vq_affinity(vq, cpu);
 135         return 0;
 136 }
 137
 138 /* Config space accessors. */
 139 #define virtio_cread(vdev, structname, member, ptr)                     \
 140         do {                                                            \
 141                 /* Must match the member's type, and be integer */      \
 142                 if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \
 143                         (*ptr) = 1;                                     \
 144                                                                         \
 145                 switch (sizeof(*ptr)) {                                 \
 146                 case 1:                                                 \
 147                         *(ptr) = virtio_cread8(vdev,                    \
 148                                                offsetof(structname, member)); \
 149                         break;                                          \
 150                 case 2:                                                 \
 151                         *(ptr) = virtio_cread16(vdev,                   \
 152                                                 offsetof(structname, member)); \
 153                         break;                                          \
 154                 case 4:                                                 \
 155                         *(ptr) = virtio_cread32(vdev,                   \
 156                                                 offsetof(structname, member)); \
 157                         break;                                          \
 158                 case 8:                                                 \
 159                         *(ptr) = virtio_cread64(vdev,                   \
 160                                                 offsetof(structname, member)); \
 161                         break;                                          \
 162                 default:                                                \
 163                         BUG();                                          \
 164                 }                                                       \
 165         } while(0)
 166
 167 /* Config space accessors. */
 168 #define virtio_cwrite(vdev, structname, member, ptr)                    \
 169         do {                                                            \
 170                 /* Must match the member's type, and be integer */      \
 171                 if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \
 172                         BUG_ON((*ptr) == 1);                            \
 173                                                                         \
 174                 switch (sizeof(*ptr)) {                                 \
 175                 case 1:                                                 \
 176                         virtio_cwrite8(vdev,                            \
 177                                        offsetof(structname, member),    \
 178                                        *(ptr));                         \
 179                         break;                                          \
 180                 case 2:                                                 \
 181                         virtio_cwrite16(vdev,                           \
 182                                         offsetof(structname, member),   \
 183                                         *(ptr));                        \
 184                         break;                                          \
 185                 case 4:                                                 \
 186                         virtio_cwrite32(vdev,                           \
 187                                         offsetof(structname, member),   \
 188                                         *(ptr));                        \
 189                         break;                                          \
 190                 case 8:                                                 \
 191                         virtio_cwrite64(vdev,                           \
 192                                         offsetof(structname, member),   \
 193                                         *(ptr));                        \
 194                         break;                                          \
 195                 default:                                                \
 196                         BUG();                                          \
 197                 }                                                       \
 198         } while(0)
 199
 200 static inline u8 virtio_cread8(struct virtio_device *vdev, unsigned int offset)
 201 {
 202         u8 ret;
 203         vdev->config->get(vdev, offset, &ret, sizeof(ret));
 204         return ret;
 205 }
 206
 207 static inline void virtio_cread_bytes(struct virtio_device *vdev,
 208                                       unsigned int offset,
 209                                       void *buf, size_t len)
 210 {
 211         vdev->config->get(vdev, offset, buf, len);
 212 }
 213
 214 static inline void virtio_cwrite8(struct virtio_device *vdev,
 215                                   unsigned int offset, u8 val)
 216 {
 217         vdev->config->set(vdev, offset, &val, sizeof(val));
 218 }
 219
 220 static inline u16 virtio_cread16(struct virtio_device *vdev,
 221                                  unsigned int offset)
 222 {
 223         u16 ret;
 224         vdev->config->get(vdev, offset, &ret, sizeof(ret));
 225         return ret;
 226 }
 227
 228 static inline void virtio_cwrite16(struct virtio_device *vdev,
 229                                    unsigned int offset, u16 val)
 230 {
 231         vdev->config->set(vdev, offset, &val, sizeof(val));
 232 }
 233
 234 static inline u32 virtio_cread32(struct virtio_device *vdev,
 235                                  unsigned int offset)
 236 {
 237         u32 ret;
 238         vdev->config->get(vdev, offset, &ret, sizeof(ret));
 239         return ret;
 240 }
 241
 242 static inline void virtio_cwrite32(struct virtio_device *vdev,
 243                                    unsigned int offset, u32 val)
 244 {
 245         vdev->config->set(vdev, offset, &val, sizeof(val));
 246 }
 247
 248 static inline u64 virtio_cread64(struct virtio_device *vdev,
 249                                  unsigned int offset)
 250 {
 251         u64 ret;
 252         vdev->config->get(vdev, offset, &ret, sizeof(ret));
 253         return ret;
 254 }
 255
 256 static inline void virtio_cwrite64(struct virtio_device *vdev,
 257                                    unsigned int offset, u64 val)
 258 {
 259         vdev->config->set(vdev, offset, &val, sizeof(val));
 260 }
 261
 262 /* Conditional config space accessors. */
 263 #define virtio_cread_feature(vdev, fbit, structname, member, ptr)       \
 264         ({                                                              \
 265                 int _r = 0;                                             \
 266                 if (!virtio_has_feature(vdev, fbit))                    \
 267                         _r = -ENOENT;                                   \
 268                 else                                                    \
 269                         virtio_cread((vdev), structname, member, ptr);  \
 270                 _r;                                                     \
 271         })
 272
 273 #endif /* _LINUX_VIRTIO_CONFIG_H */