Commit 0b90d062 authored by Rusty Russell's avatar Rusty Russell
Browse files

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: default avatarRusty Russell <rusty@rustcorp.com.au>
parent bb478d8b

include/linux/virtio_config.h

+134 −0
Original line number Diff line number Diff line
@@ -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 */