//
// Do NOT modify or remove this copyright and license
//
// Copyright (c) 2020-2023 Seagate Technology LLC and/or its Affiliates, All Rights Reserved
//
// This software is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
//
// ******************************************************************************************
// \file raid_scan_helper.h
// \brief Defines the structures, types, and function to assist with scanning for devices in different RAID configurations.

#pragma once

#include "common.h"

#if defined (__cplusplus)
extern "C"
{
#endif

    /* How this is supposed to be used:
    The general idea is this: Each OS has some information it can use to detect what may or may not be a RAID.
    This is handled at a low-level while scanning for devices.
    Any device that is suspected of being part of a RAID configuration will have the OS's handle passed off to a RAID implementation to use as a place to scan with RAID specific IOCTLs
    This code creates a linked list that should make it easy to add those handles to a short list that can be passed on to the RAID implementations to use how they are needed.
    
    This is currently being used by CSMI in WIndows, but further support will be added as other RAID libraries are supported.
    */

    //using bit field here to reduce memory usage, but can be removed if this causes problems
    //This is intended to hint which RAID type a device is, if there is a way to know or guess what it is in a given OS. This may not always be possible, so setting unknown will force scanning any implemented RAID
    //setup as bitfield/booleans since so that guesses can be take for multiple types of RAID in case it cannot be narrowed down to one specific type
    //NOTE: Not all RAIDs are supported when this comment was written.
    //NOTE: It is not possible to support every type of RAID. Many are not supportable since they do not provide a method to talk to individual drives in a RAID configuration, only those that do will be supported.
    typedef struct _raidTypeHint
    {
        bool unknownRAID    : 1;//Setting this means it is not a known RAID from quick OS level glance and any RAID library that sees this device should try to use it and check it.
        bool csmiRAID       : 1;//CSMI RAID IOs. Mostly Intel motherboards, but some other drivers may support it
        bool cissRAID       : 1;//HP CISS RAID controllers (Not supported yet)
        bool megaRAID       : 1;//LSI/Avago/Broadcom MegaRAID IOCTLs (Not supported yet)
        bool adaptecRAID    : 1;//Adaptec/PMC/Microsemi RAID (Not supported yet)
        bool highpointRAID  : 1;//Highpoint RAID  (Not supported yet)
        bool areccaRAID     : 1;//Arecca RAID  (Not supported yet)
        bool intelVROC      : 1;//Intel VROC - NVMe (Not supported yet)
    }raidTypeHint;

    //Define the max string length
    #define RAID_HANDLE_STRING_MAX_LEN UINT8_C(24)

    typedef struct _raidHandleToScan
    {
        struct _raidHandleToScan * next; //must be declared like this to work with older GCC compilers.
        char handle[RAID_HANDLE_STRING_MAX_LEN];
        raidTypeHint raidHint;
    }raidHandleToScan, *ptrRaidHandleToScan;

    //Function to make it easy to add another entry to the list
    //Returns pointer to the added entry.
    //Entry is always added in currentPtr->next
    ptrRaidHandleToScan add_RAID_Handle(ptrRaidHandleToScan currentPtr, char *handleToScan, raidTypeHint raidHint);

    //Same as above, but checks to make sure that the provided handle is not already part of the list to scan - helpful for some configurations where a RAID also has JBOD/passthrough disks available on the same HBA
    //If already in the list, currentPtr is returned
    ptrRaidHandleToScan add_RAID_Handle_If_Not_In_List(ptrRaidHandleToScan listBegin, ptrRaidHandleToScan currentPtr, char *handleToScan, raidTypeHint raidHint);

    //Make it easier to remove an item. Useful when scanning multiple RAID libs because the first RAID lib can remove handles that did in fact work so that they are not scanned again by another RAID library.
    //returns a pointer to the entry after "toRemove", which can be NULL
    ptrRaidHandleToScan remove_RAID_Handle(ptrRaidHandleToScan toRemove, ptrRaidHandleToScan previous);

    //Deletes everything in the list from pointer to the beginning of the list.
    void delete_RAID_List(ptrRaidHandleToScan listBegin);

#if defined (__cplusplus)
}
#endif
