/*
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * $FreeBSD$
 */

#ifndef _VIRTIO_H_
#define _VIRTIO_H_

#include <openamp/virtqueue.h>
#include <metal/spinlock.h>

#if defined __cplusplus
extern "C" {
#endif

/* VirtIO device IDs. */
#define VIRTIO_ID_NETWORK    0x01UL
#define VIRTIO_ID_BLOCK      0x02UL
#define VIRTIO_ID_CONSOLE    0x03UL
#define VIRTIO_ID_ENTROPY    0x04UL
#define VIRTIO_ID_BALLOON    0x05UL
#define VIRTIO_ID_IOMEMORY   0x06UL
#define VIRTIO_ID_RPMSG      0x07UL /* remote processor messaging */
#define VIRTIO_ID_SCSI       0x08UL
#define VIRTIO_ID_9P         0x09UL
#define VIRTIO_DEV_ANY_ID    (-1)UL

/* Status byte for guest to report progress. */
#define VIRTIO_CONFIG_STATUS_ACK       0x01
#define VIRTIO_CONFIG_STATUS_DRIVER    0x02
#define VIRTIO_CONFIG_STATUS_DRIVER_OK 0x04
#define VIRTIO_CONFIG_STATUS_NEEDS_RESET 0x40
#define VIRTIO_CONFIG_STATUS_FAILED    0x80

/* Virtio device role */
#define VIRTIO_DEV_MASTER	0UL
#define VIRTIO_DEV_SLAVE	1UL

struct virtio_device_id {
	uint32_t device;
	uint32_t vendor;
};

/*
 * Generate interrupt when the virtqueue ring is
 * completely used, even if we've suppressed them.
 */
#define VIRTIO_F_NOTIFY_ON_EMPTY (1 << 24)

/*
 * The guest should never negotiate this feature; it
 * is used to detect faulty drivers.
 */
#define VIRTIO_F_BAD_FEATURE (1 << 30)

/*
 * Some VirtIO feature bits (currently bits 28 through 31) are
 * reserved for the transport being used (eg. virtio_ring), the
 * rest are per-device feature bits.
 */
#define VIRTIO_TRANSPORT_F_START      28
#define VIRTIO_TRANSPORT_F_END        32

typedef void (*virtio_dev_reset_cb)(struct virtio_device *vdev);

struct virtio_dispatch;

struct virtio_feature_desc {
	uint32_t vfd_val;
	const char *vfd_str;
};

/**
 * struct virtio_vring_info
 * @vq virtio queue
 * @info vring alloc info
 * @notifyid vring notify id
 * @io metal I/O region of the vring memory, can be NULL
 */
struct virtio_vring_info {
	struct virtqueue *vq;
	struct vring_alloc_info info;
	uint32_t notifyid;
	struct metal_io_region *io;
};

/*
 * Structure definition for virtio devices for use by the
 * applications/drivers
 */

struct virtio_device {
	uint32_t notifyid; /**< unique position on the virtio bus */
	struct virtio_device_id id; /**< the device type identification
				      *  (used to match it with a driver
				      */
	uint64_t features; /**< the features supported by both ends. */
	unsigned int role; /**< if it is virtio backend or front end. */
	virtio_dev_reset_cb reset_cb; /**< user registered device callback */
	const struct virtio_dispatch *func; /**< Virtio dispatch table */
	void *priv; /**< TODO: remove pointer to virtio_device private data */
	unsigned int vrings_num; /**< number of vrings */
	struct virtio_vring_info *vrings_info;
};

/*
 * Helper functions.
 */
const char *virtio_dev_name(uint16_t devid);
void virtio_describe(struct virtio_device *dev, const char *msg,
		     uint32_t features,
		     struct virtio_feature_desc *feature_desc);

/*
 * Functions for virtio device configuration as defined in Rusty Russell's
 * paper.
 * Drivers are expected to implement these functions in their respective codes.
 */

struct virtio_dispatch {
	uint8_t (*get_status)(struct virtio_device *dev);
	void (*set_status)(struct virtio_device *dev, uint8_t status);
	uint32_t (*get_features)(struct virtio_device *dev);
	void (*set_features)(struct virtio_device *dev, uint32_t feature);
	uint32_t (*negotiate_features)(struct virtio_device *dev,
				       uint32_t features);

	/*
	 * Read/write a variable amount from the device specific (ie, network)
	 * configuration region. This region is encoded in the same endian as
	 * the guest.
	 */
	void (*read_config)(struct virtio_device *dev, uint32_t offset,
			    void *dst, int length);
	void (*write_config)(struct virtio_device *dev, uint32_t offset,
			     void *src, int length);
	void (*reset_device)(struct virtio_device *dev);
	void (*notify)(struct virtqueue *vq);
};

int virtio_create_virtqueues(struct virtio_device *vdev, unsigned int flags,
			     unsigned int nvqs, const char *names[],
			     vq_callback callbacks[]);

#if defined __cplusplus
}
#endif

#endif				/* _VIRTIO_H_ */