/*
 * Copyright 2026 John Davis. All rights reserved.
 * Distributed under the terms of the MIT License.
 */
#ifndef _HYPERV_SCSI_PROTOCOL_H_
#define _HYPERV_SCSI_PROTOCOL_H_


#include <hyperv_spec.h>


#define HV_SCSI_RING_SIZE                       0x200000
#define HV_SCSI_RX_PKT_BUFFER_SIZE      512

#define HV_SCSI_MAX_SCSI_DEVICES        64U
#define HV_SCSI_MAX_IDE_DEVICES         1U

#define HV_SCSI_CDB_SIZE                        0x10
#define HV_SCSI_SENSE_SIZE                      0x14
#define HV_SCSI_LEGACY_SENSE_SIZE       0x12

#define HV_SCSI_MAX_BLOCK_SIZE          2048
#define HV_SCSI_MAX_BLOCK_COUNT         128
#define HV_SCSI_MAX_BUFFER_SIZE         0x40000
#define HV_SCSI_MAX_BUFFER_SEGMENTS     (HV_SCSI_MAX_BUFFER_SIZE / HV_PAGE_SIZE)
#define HV_SCSI_MAX_BUFFER_PAGES        (HV_SCSI_MAX_BUFFER_SEGMENTS + 1)

#define HV_SCSI_TIMEOUT_US                      HV_MS_TO_US(10000)
#define HV_SCSI_MAX_REQUESTS            2


// Hyper-V SCSI version
#define MAKE_SCSI_VERSION(major, minor) ((((major) << 8) & 0xFF00) | ((minor) & 0x00FF))
#define GET_SCSI_VERSION_MAJOR(version) (((version) >> 8) & 0xFF)
#define GET_SCSI_VERSION_MINOR(version) ((version) & 0xFF)

#define HV_SCSI_VERSION_WIN2008                 MAKE_SCSI_VERSION(2, 0)
#define HV_SCSI_VERSION_WIN2008R2               MAKE_SCSI_VERSION(4, 2)
#define HV_SCSI_VERSION_WIN8                    MAKE_SCSI_VERSION(5, 1)
#define HV_SCSI_VERSION_WIN81                   MAKE_SCSI_VERSION(6, 0)
#define HV_SCSI_VERSION_WIN10                   MAKE_SCSI_VERSION(6, 1)


static const uint32 hv_scsi_versions[] = {
        HV_SCSI_VERSION_WIN10,
        HV_SCSI_VERSION_WIN81,
        HV_SCSI_VERSION_WIN8,
        HV_SCSI_VERSION_WIN2008R2,
        HV_SCSI_VERSION_WIN2008
};
static const uint32 hv_scsi_version_count = sizeof(hv_scsi_versions)
        / sizeof(hv_scsi_versions[0]);


// SCSI request direction
enum {
        HV_SCSI_DIRECTION_WRITE         = 0,
        HV_SCSI_DIRECTION_READ          = 1,
        HV_SCSI_DIRECTION_UNKNOWN       = 2
};


#define HV_SCSI_SRB_FLAGS_DISABLE_SYNC_TRANSFER (1 << 3)
#define HV_SCSI_SRB_FLAGS_DISABLE_AUTOSENSE             (1 << 5)
#define HV_SCSI_SRB_FLAGS_DATA_IN                               (1 << 6)
#define HV_SCSI_SRB_FLAGS_DATA_OUT                              (1 << 7)


// SCSI request extension on Windows 8 / Windows Server 2012 and newer
typedef struct {
        uint16  reserved;
        uint8   queue_tag;
        uint8   queue_action;
        uint32  srb_flags;
        uint32  timeout;
        uint32  queue_sort_by;
} _PACKED hv_scsi_request_win8_extension;


// SCSI message types
enum {
        HV_SCSI_MSGTYPE_COMPLETE_IO                             = 1,
        HV_SCSI_MSGTYPE_REMOVE_DEVICE                   = 2,
        HV_SCSI_MSGTYPE_EXECUTE_SRB                             = 3,
        HV_SCSI_MSGTYPE_RESET_LUN                               = 4,
        HV_SCSI_MSGTYPE_RESET_ADAPTER                   = 5,
        HV_SCSI_MSGTYPE_RESET_BUS                               = 6,
        HV_SCSI_MSGTYPE_BEGIN_INIT                              = 7,
        HV_SCSI_MSGTYPE_END_INIT                                = 8,
        HV_SCSI_MSGTYPE_QUERY_PROTOCOL_VER              = 9,
        HV_SCSI_MSGTYPE_QUERY_PROPERTIES                = 10,
        HV_SCSI_MSGTYPE_ENUM_BUS                                = 11,
        HV_SCSI_MSGTYPE_FCHBA_DATA                              = 12,
        HV_SCSI_MSGTYPE_CREATE_SUB_CHANNELS             = 13
};


#define HV_SCSI_FLAG_REQUEST_COMPLETION         1
#define HV_SCSI_SUCCESS                                         0


// SCSI message header
typedef struct {
        uint32  type;
        uint32  flags;
        uint32  status;
} _PACKED hv_scsi_msg_header;


// SCSI request message sent to Hyper-V
typedef struct {
        hv_scsi_msg_header      header;

        uint16  length;
        uint8   srb_status;
        uint8   scsi_status;

        uint8   port;
        uint8   path_id;
        uint8   target_id;
        uint8   lun;

        uint8   cdb_length;
        uint8   sense_info_length;
        uint8   direction;
        uint8   reserved;
        uint32  data_length;

        union {
                uint8   cdb[HV_SCSI_CDB_SIZE];
                uint8   sense[HV_SCSI_SENSE_SIZE];
        };

        hv_scsi_request_win8_extension win8_extension;
} _PACKED hv_scsi_msg_request;


#define HV_SCSI_FLAG_SUPPORTS_MULTI_CHANNEL             1

// SCSI channel properties message
typedef struct {
        hv_scsi_msg_header      header;

        uint32  reserved1;
        uint16  max_channels;
        uint16  reserved2;

        uint32  flags;
        uint32  max_transfer_bytes;

        uint64  reserved3;
} _PACKED hv_scsi_msg_channel_properties;


// SCSI protocol message
typedef struct {
        hv_scsi_msg_header      header;

        uint16  version;
        uint16  revision; // Always zero for this driver
} _PACKED hv_scsi_msg_protocol;


// SCSI Fibre Channel WWN message
typedef struct {
        uint8   primary_active;
        uint8   reserved[3];
        uint8   primary_port_wwn[8];
        uint8   primary_node_wwn[8];
        uint8   secondary_port_wwn[8];
        uint8   secondary_node_wwn[8];
} _PACKED hv_scsi_msg_fibre_channel_wwn;


// SCSI combined message
typedef union {
        hv_scsi_msg_header                              header;
        hv_scsi_msg_request                             request;
        hv_scsi_msg_channel_properties  channel_properties;
        hv_scsi_msg_protocol                    protocol;
        hv_scsi_msg_fibre_channel_wwn   fibre_channel_wwn;

        uint16                                                  sub_channels;
        uint8                                                   padding[sizeof(hv_scsi_msg_header) + 0x34];
} _PACKED hv_scsi_msg;


#endif