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>

1 files changed, 134 insertions, 0 deletions

diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
index 29b9104232b4..490a4bbd59a3 100644
--- 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 */