#ifndef _LINUX_VIRTIO_CONFIG_H
#define _LINUX_VIRTIO_CONFIG_H
/* This header, excluding the #ifdef __KERNEL__ part, is BSD licensed so
 * anyone can use the definitions to implement compatible drivers/servers.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of IBM nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE. */

#include <linux/types.h>

#define VIRTIO_CONFIG_S_ACKNOWLEDGE	1
#define VIRTIO_CONFIG_S_DRIVER		2
#define VIRTIO_CONFIG_S_DRIVER_OK	4
#define VIRTIO_CONFIG_S_FAILED		0x80

#define VIRTIO_TRANSPORT_F_START	28
#define VIRTIO_TRANSPORT_F_END		32

#define VIRTIO_F_NOTIFY_ON_EMPTY	24

#ifdef __KERNEL__
#include <linux/err.h>
#include <linux/bug.h>
#include <linux/virtio.h>

typedef void vq_callback_t(struct virtqueue *);
struct virtio_config_ops {
	void (*get)(struct virtio_device *vdev, unsigned offset,
		    void *buf, unsigned len);
	void (*set)(struct virtio_device *vdev, unsigned offset,
		    const void *buf, unsigned len);
	u8 (*get_status)(struct virtio_device *vdev);
	void (*set_status)(struct virtio_device *vdev, u8 status);
	void (*reset)(struct virtio_device *vdev);
	int (*find_vqs)(struct virtio_device *, unsigned nvqs,
			struct virtqueue *vqs[],
			vq_callback_t *callbacks[],
			const char *names[]);
	void (*del_vqs)(struct virtio_device *);
	u32 (*get_features)(struct virtio_device *vdev);
	void (*finalize_features)(struct virtio_device *vdev);
	const char *(*bus_name)(struct virtio_device *vdev);
};

void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
					 unsigned int fbit);

static inline bool virtio_has_feature(const struct virtio_device *vdev,
				      unsigned int fbit)
{
	
	if (__builtin_constant_p(fbit))
		BUILD_BUG_ON(fbit >= 32);
	else
		BUG_ON(fbit >= 32);

	if (fbit < VIRTIO_TRANSPORT_F_START)
		virtio_check_driver_offered_feature(vdev, fbit);

	return test_bit(fbit, vdev->features);
}

#define virtio_config_val(vdev, fbit, offset, v) \
	virtio_config_buf((vdev), (fbit), (offset), (v), sizeof(*v))

#define virtio_config_val_len(vdev, fbit, offset, v, len) \
	virtio_config_buf((vdev), (fbit), (offset), (v), (len))

static inline int virtio_config_buf(struct virtio_device *vdev,
				    unsigned int fbit,
				    unsigned int offset,
				    void *buf, unsigned len)
{
	if (!virtio_has_feature(vdev, fbit))
		return -ENOENT;

	vdev->config->get(vdev, offset, buf, len);
	return 0;
}

static inline
struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev,
					vq_callback_t *c, const char *n)
{
	vq_callback_t *callbacks[] = { c };
	const char *names[] = { n };
	struct virtqueue *vq;
	int err = vdev->config->find_vqs(vdev, 1, &vq, callbacks, names);
	if (err < 0)
		return ERR_PTR(err);
	return vq;
}

static inline
const char *virtio_bus_name(struct virtio_device *vdev)
{
	if (!vdev->config->bus_name)
		return "virtio";
	return vdev->config->bus_name(vdev);
}

#endif 
#endif