virtio_config: introduce size-based accessors.

This lets the us do endian conversion if necessary, and insulates the
drivers from that change.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
index 29b9104232b40c038bf29969d9c63795e8575fce..490a4bbd59a3ac9200c7ed766ac066201ba2b8e1 100644 (file)
--- a/include/linux/virtio_config.h
+++ b/include/linux/virtio_config.h
@@ -162,5 +162,139 @@ int virtqueue_set_affinity(struct virtqueue *vq, int cpu)
        return 0;
 }
 
+/* Config space accessors. */
+#define virtio_cread(vdev, structname, member, ptr)                    \
+       do {                                                            \
+               /* Must match the member's type, and be integer */      \
+               if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \
+                       (*ptr) = 1;                                     \
+                                                                       \
+               switch (sizeof(*ptr)) {                                 \
+               case 1:                                                 \
+                       *(ptr) = virtio_cread8(vdev,                    \
+                                              offsetof(structname, member)); \
+                       break;                                          \
+               case 2:                                                 \
+                       *(ptr) = virtio_cread16(vdev,                   \
+                                               offsetof(structname, member)); \
+                       break;                                          \
+               case 4:                                                 \
+                       *(ptr) = virtio_cread32(vdev,                   \
+                                               offsetof(structname, member)); \
+                       break;                                          \
+               case 8:                                                 \
+                       *(ptr) = virtio_cread64(vdev,                   \
+                                               offsetof(structname, member)); \
+                       break;                                          \
+               default:                                                \
+                       BUG();                                          \
+               }                                                       \
+       } while(0)
+
+/* Config space accessors. */
+#define virtio_cwrite(vdev, structname, member, ptr)                   \
+       do {                                                            \
+               /* Must match the member's type, and be integer */      \
+               if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \
+                       BUG_ON((*ptr) == 1);                            \
+                                                                       \
+               switch (sizeof(*ptr)) {                                 \
+               case 1:                                                 \
+                       virtio_cwrite8(vdev,                            \
+                                      offsetof(structname, member),    \
+                                      *(ptr));                         \
+                       break;                                          \
+               case 2:                                                 \
+                       virtio_cwrite16(vdev,                           \
+                                       offsetof(structname, member),   \
+                                       *(ptr));                        \
+                       break;                                          \
+               case 4:                                                 \
+                       virtio_cwrite32(vdev,                           \
+                                       offsetof(structname, member),   \
+                                       *(ptr));                        \
+                       break;                                          \
+               case 8:                                                 \
+                       virtio_cwrite64(vdev,                           \
+                                       offsetof(structname, member),   \
+                                       *(ptr));                        \
+                       break;                                          \
+               default:                                                \
+                       BUG();                                          \
+               }                                                       \
+       } while(0)
+
+static inline u8 virtio_cread8(struct virtio_device *vdev, unsigned int offset)
+{
+       u8 ret;
+       vdev->config->get(vdev, offset, &ret, sizeof(ret));
+       return ret;
+}
+
+static inline void virtio_cread_bytes(struct virtio_device *vdev,
+                                     unsigned int offset,
+                                     void *buf, size_t len)
+{
+       vdev->config->get(vdev, offset, buf, len);
+}
+
+static inline void virtio_cwrite8(struct virtio_device *vdev,
+                                 unsigned int offset, u8 val)
+{
+       vdev->config->set(vdev, offset, &val, sizeof(val));
+}
+
+static inline u16 virtio_cread16(struct virtio_device *vdev,
+                                unsigned int offset)
+{
+       u16 ret;
+       vdev->config->get(vdev, offset, &ret, sizeof(ret));
+       return ret;
+}
+
+static inline void virtio_cwrite16(struct virtio_device *vdev,
+                                  unsigned int offset, u16 val)
+{
+       vdev->config->set(vdev, offset, &val, sizeof(val));
+}
+
+static inline u32 virtio_cread32(struct virtio_device *vdev,
+                                unsigned int offset)
+{
+       u32 ret;
+       vdev->config->get(vdev, offset, &ret, sizeof(ret));
+       return ret;
+}
+
+static inline void virtio_cwrite32(struct virtio_device *vdev,
+                                  unsigned int offset, u32 val)
+{
+       vdev->config->set(vdev, offset, &val, sizeof(val));
+}
+
+static inline u64 virtio_cread64(struct virtio_device *vdev,
+                                unsigned int offset)
+{
+       u64 ret;
+       vdev->config->get(vdev, offset, &ret, sizeof(ret));
+       return ret;
+}
+
+static inline void virtio_cwrite64(struct virtio_device *vdev,
+                                  unsigned int offset, u64 val)
+{
+       vdev->config->set(vdev, offset, &val, sizeof(val));
+}
+
+/* Conditional config space accessors. */
+#define virtio_cread_feature(vdev, fbit, structname, member, ptr)      \
+       ({                                                              \
+               int _r = 0;                                             \
+               if (!virtio_has_feature(vdev, fbit))                    \
+                       _r = -ENOENT;                                   \
+               else                                                    \
+                       virtio_cread((vdev), structname, member, ptr);  \
+               _r;                                                     \
+       })
 
 #endif /* _LINUX_VIRTIO_CONFIG_H */