/*
 * **********************************************************************
 *
 * ld_pd_map.c
 *
 * Solaris MegaRAID device driver for SAS2.0 controllers
 * Copyright (c) 2008-2012, LSI Logic Corporation.
 * All rights reserved.
 *
 * Version:
 * Author:
 *              Swaminathan K S
 *              Arun Chandrashekhar
 *              Manju R
 *              Rasheed
 *              Shakeel Bukhari
 *
 *
 * This module contains functions for device drivers
 * to get pd-ld mapping information.
 *
 * **********************************************************************
 */
/*
 * Copyright 2015 Garrett D'Amore <garrett@damore.org>
 * Copyright 2017 Citrus IT Limited. All rights reserved.
 */

#include <sys/scsi/scsi.h>
#include "mr_sas.h"
#include "ld_pd_map.h"

/*
 * This function will check if FAST IO is possible on this logical drive
 * by checking the EVENT information available in the driver
 */
#define MR_LD_STATE_OPTIMAL 3
#define ABS_DIFF(a, b)   (((a) > (b)) ? ((a) - (b)) : ((b) - (a)))

static void mr_update_load_balance_params(MR_FW_RAID_MAP_ALL *,
    PLD_LOAD_BALANCE_INFO);

#define FALSE 0
#define TRUE 1

typedef U64     REGION_KEY;
typedef U32     REGION_LEN;
extern int      debug_level_g;


MR_LD_RAID
*MR_LdRaidGet(U32 ld, MR_FW_RAID_MAP_ALL *map)
{
        return (&map->raidMap.ldSpanMap[ld].ldRaid);
}

U16
MR_GetLDTgtId(U32 ld, MR_FW_RAID_MAP_ALL *map)
{
        return (map->raidMap.ldSpanMap[ld].ldRaid.targetId);
}


static MR_SPAN_BLOCK_INFO *
MR_LdSpanInfoGet(U32 ld, MR_FW_RAID_MAP_ALL *map)
{
        return (&map->raidMap.ldSpanMap[ld].spanBlock[0]);
}

static U8
MR_LdDataArmGet(U32 ld, U32 armIdx, MR_FW_RAID_MAP_ALL *map)
{
        return (map->raidMap.ldSpanMap[ld].dataArmMap[armIdx]);
}

static U16
MR_ArPdGet(U32 ar, U32 arm, MR_FW_RAID_MAP_ALL *map)
{
        return (map->raidMap.arMapInfo[ar].pd[arm]);
}

static U16
MR_LdSpanArrayGet(U32 ld, U32 span, MR_FW_RAID_MAP_ALL *map)
{
        return (map->raidMap.ldSpanMap[ld].spanBlock[span].span.arrayRef);
}

static U16
MR_PdDevHandleGet(U32 pd, MR_FW_RAID_MAP_ALL *map)
{
        return (map->raidMap.devHndlInfo[pd].curDevHdl);
}

U16
MR_TargetIdToLdGet(U32 ldTgtId, MR_FW_RAID_MAP_ALL *map)
{
        return (map->raidMap.ldTgtIdToLd[ldTgtId]);
}

U16
MR_CheckDIF(U32 ldTgtId, MR_FW_RAID_MAP_ALL *map)
{
        MR_LD_RAID      *raid;
        U32             ld;

        ld = MR_TargetIdToLdGet(ldTgtId, map);

        if (ld >= MAX_LOGICAL_DRIVES) {
                return (FALSE);
        }

        raid = MR_LdRaidGet(ld, map);

        return (raid->capability.ldPiMode == 0x8);
}

static MR_LD_SPAN *
MR_LdSpanPtrGet(U32 ld, U32 span, MR_FW_RAID_MAP_ALL *map)
{
        return (&map->raidMap.ldSpanMap[ld].spanBlock[span].span);
}

/*
 * This function will validate Map info data provided by FW
 */
U8
MR_ValidateMapInfo(MR_FW_RAID_MAP_ALL *map, PLD_LOAD_BALANCE_INFO lbInfo)
{
        MR_FW_RAID_MAP *pFwRaidMap = &map->raidMap;
        U32 fwsize = sizeof (MR_FW_RAID_MAP) - sizeof (MR_LD_SPAN_MAP) +
            (sizeof (MR_LD_SPAN_MAP) * pFwRaidMap->ldCount);

        if (pFwRaidMap->totalSize != fwsize) {

                con_log(CL_ANN1, (CE_NOTE,
                    "map info structure size 0x%x is "
                    "not matching with ld count\n", fwsize));
                /* sizeof (foo) returns size_t, which is *LONG*. */
                con_log(CL_ANN1, (CE_NOTE, "span map 0x%x total size 0x%x\n",\
                    (int)sizeof (MR_LD_SPAN_MAP), pFwRaidMap->totalSize));

                return (0);
        }

        mr_update_load_balance_params(map, lbInfo);

        return (1);
}

U32
MR_GetSpanBlock(U32 ld, U64 row, U64 *span_blk, MR_FW_RAID_MAP_ALL *map,
    int *div_error)
{
        MR_SPAN_BLOCK_INFO *pSpanBlock = MR_LdSpanInfoGet(ld, map);
        MR_QUAD_ELEMENT *qe;
        MR_LD_RAID      *raid = MR_LdRaidGet(ld, map);
        U32             span, j;

        for (span = 0; span < raid->spanDepth; span++, pSpanBlock++) {
                for (j = 0; j < pSpanBlock->block_span_info.noElements; j++) {
                        qe = &pSpanBlock->block_span_info.quads[j];
                        if (qe->diff == 0) {
                                *div_error = 1;
                                return (span);
                        }
                        if (qe->logStart <= row && row <= qe->logEnd &&
                            (((row - qe->logStart) % qe->diff)) == 0) {
                                if (span_blk != NULL) {
                                        U64     blk;
                                        blk = ((row - qe->logStart) /
                                            (qe->diff));

                                        blk = (blk + qe->offsetInSpan) <<
                                            raid->stripeShift;
                                        *span_blk = blk;
                                }
                                return (span);
                        }
                }
        }
        return (span);
}


/*
 * *************************************************************
 *
 * This routine calculates the arm, span and block for
 * the specified stripe and reference in stripe.
 *
 * Inputs :
 *
 *    ld   - Logical drive number
 *    stripRow        - Stripe number
 *    stripRef    - Reference in stripe
 *
 * Outputs :
 *
 *    span          - Span number
 *    block         - Absolute Block number in the physical disk
 */
U8
MR_GetPhyParams(struct mrsas_instance *instance, U32 ld, U64 stripRow,
    U16 stripRef, U64 *pdBlock, U16 *pDevHandle,
    MPI2_SCSI_IO_VENDOR_UNIQUE *pRAID_Context, MR_FW_RAID_MAP_ALL *map)
{
        MR_LD_RAID      *raid = MR_LdRaidGet(ld, map);
        U32             pd, arRef;
        U8              physArm, span;
        U64             row;
        int             error_code = 0;
        U8              retval = TRUE;
        U32             rowMod;
        U32             armQ;
        U32             arm;

        ASSERT(raid->rowDataSize != 0);

        row = (stripRow / raid->rowDataSize);

        if (raid->level == 6) {
                U32 logArm =  (stripRow % (raid->rowDataSize));

                if (raid->rowSize == 0) {
                        return (FALSE);
                }
                rowMod = (row % (raid->rowSize));
                armQ = raid->rowSize-1-rowMod;
                arm = armQ + 1 + logArm;
                if (arm >= raid->rowSize)
                        arm -= raid->rowSize;
                physArm = (U8)arm;
        } else {
                if (raid->modFactor == 0)
                        return (FALSE);
                physArm = MR_LdDataArmGet(ld,
                    (stripRow % (raid->modFactor)), map);
        }
        if (raid->spanDepth == 1) {
                span = 0;
                *pdBlock = row << raid->stripeShift;
        } else
                span = (U8)MR_GetSpanBlock(ld, row, pdBlock, map, &error_code);

        if (error_code == 1)
                return (FALSE);

        /* Get the array on which this span is present. */
        arRef           = MR_LdSpanArrayGet(ld, span, map);
        /* Get the Pd. */
        pd              = MR_ArPdGet(arRef, physArm, map);
        /* Get dev handle from Pd. */
        if (pd != MR_PD_INVALID) {
                *pDevHandle     = MR_PdDevHandleGet(pd, map);
        } else {
                *pDevHandle = MR_PD_INVALID; /* set dev handle as invalid. */
                if (raid->level >= 5 && (!instance->gen3 ||
                    raid->regTypeReqOnRead != REGION_TYPE_UNUSED)) {
                        pRAID_Context->regLockFlags = REGION_TYPE_EXCLUSIVE;
                } else if (raid->level == 1) {
                        /* Get Alternate Pd. */
                        pd = MR_ArPdGet(arRef, physArm + 1, map);
                        /* Get dev handle from Pd. */
                        if (pd != MR_PD_INVALID)
                                *pDevHandle = MR_PdDevHandleGet(pd, map);
                }
        }

        *pdBlock += stripRef + MR_LdSpanPtrGet(ld, span, map)->startBlk;

        pRAID_Context->spanArm = (span << RAID_CTX_SPANARM_SPAN_SHIFT) |
            physArm;

        return (retval);
}



/*
 * ***********************************************************************
 *
 * MR_BuildRaidContext function
 *
 * This function will initiate command processing.  The start/end row and strip
 * information is calculated then the lock is acquired.
 * This function will return 0 if region lock
 * was acquired OR return num strips ???
 */

U8
MR_BuildRaidContext(struct mrsas_instance *instance,
    struct IO_REQUEST_INFO *io_info, MPI2_SCSI_IO_VENDOR_UNIQUE *pRAID_Context,
    MR_FW_RAID_MAP_ALL *map)
{
        MR_LD_RAID      *raid;
        U32             ld, stripSize, stripe_mask;
        U64             endLba, endStrip, endRow;
        U64             start_row, start_strip;
        REGION_KEY      regStart;
        REGION_LEN      regSize;
        U8              num_strips, numRows;
        U16             ref_in_start_stripe;
        U16             ref_in_end_stripe;

        U64             ldStartBlock;
        U32             numBlocks, ldTgtId;
        U8              isRead;
        U8              retval = 0;

        ldStartBlock = io_info->ldStartBlock;
        numBlocks = io_info->numBlocks;
        ldTgtId = io_info->ldTgtId;
        isRead = io_info->isRead;

        if (map == NULL) {
                io_info->fpOkForIo = FALSE;
                return (FALSE);
        }

        ld = MR_TargetIdToLdGet(ldTgtId, map);

        if (ld >= MAX_LOGICAL_DRIVES) {
                io_info->fpOkForIo = FALSE;
                return (FALSE);
        }

        raid = MR_LdRaidGet(ld, map);

        stripSize = 1 << raid->stripeShift;
        stripe_mask = stripSize-1;
        /*
         * calculate starting row and stripe, and number of strips and rows
         */
        start_strip             = ldStartBlock >> raid->stripeShift;
        ref_in_start_stripe     = (U16)(ldStartBlock & stripe_mask);
        endLba                  = ldStartBlock + numBlocks - 1;
        ref_in_end_stripe       = (U16)(endLba & stripe_mask);
        endStrip                = endLba >> raid->stripeShift;
        num_strips              = (U8)(endStrip - start_strip + 1);
        /* Check to make sure is not dividing by zero */
        if (raid->rowDataSize == 0)
                return (FALSE);
        start_row               =  (start_strip / raid->rowDataSize);
        endRow                  =  (endStrip  / raid->rowDataSize);
        /* get the row count */
        numRows                 = (U8)(endRow - start_row + 1);

        /*
         * calculate region info.
         */
        regStart        = start_row << raid->stripeShift;
        regSize         = stripSize;

        /* Check if we can send this I/O via FastPath */
        if (raid->capability.fpCapable) {
                if (isRead) {
                        io_info->fpOkForIo = (raid->capability.fpReadCapable &&
                            ((num_strips == 1) ||
                            raid->capability.fpReadAcrossStripe));
                } else {
                        io_info->fpOkForIo =
                            (raid->capability.fpWriteCapable &&
                            ((num_strips == 1) ||
                            raid->capability.fpWriteAcrossStripe));
                }
        } else
                io_info->fpOkForIo = FALSE;


        /*
         * Check for DIF support
         */
        if (!raid->capability.ldPiMode) {
                io_info->ldPI = FALSE;
        } else {
                io_info->ldPI = TRUE;
        }

        if (numRows == 1) {
                if (num_strips == 1) {
                        regStart += ref_in_start_stripe;
                        regSize = numBlocks;
                }
        } else {
                if (start_strip == (start_row + 1) * raid->rowDataSize - 1) {
                        regStart += ref_in_start_stripe;
                regSize = stripSize - ref_in_start_stripe;
                }

                if (numRows > 2) {
                        regSize += (numRows - 2) << raid->stripeShift;
                }

                if (endStrip == endRow * raid->rowDataSize) {
                        regSize += ref_in_end_stripe + 1;
                } else {
                        regSize += stripSize;
                }
        }

        pRAID_Context->timeoutValue = map->raidMap.fpPdIoTimeoutSec;

        if (instance->gen3) {
                pRAID_Context->regLockFlags = (isRead) ?
                    raid->regTypeReqOnRead : raid->regTypeReqOnWrite;
        } else {
                pRAID_Context->regLockFlags = (isRead) ?
                    REGION_TYPE_SHARED_READ : raid->regTypeReqOnWrite;
        }

        pRAID_Context->ldTargetId = raid->targetId;
        pRAID_Context->regLockRowLBA = regStart;
        pRAID_Context->regLockLength = regSize;
        pRAID_Context->configSeqNum = raid->seqNum;

        /*
         * Get Phy Params only if FP capable,
         * or else leave it to MR firmware to do the calculation.
         */
        if (io_info->fpOkForIo) {
                /* if fast path possible then get the physical parameters */
                retval = MR_GetPhyParams(instance, ld, start_strip,
                    ref_in_start_stripe, &io_info->pdBlock,
                    &io_info->devHandle, pRAID_Context, map);

                /* If IO on an invalid Pd, then FP is not possible. */
                if (io_info->devHandle == MR_PD_INVALID)
                        io_info->fpOkForIo = FALSE;

                return (retval);

        } else if (isRead) {
                uint_t stripIdx;

                for (stripIdx = 0; stripIdx < num_strips; stripIdx++) {
                        if (!MR_GetPhyParams(instance, ld,
                            start_strip + stripIdx, ref_in_start_stripe,
                            &io_info->pdBlock, &io_info->devHandle,
                            pRAID_Context, map)) {
                                return (TRUE);
                        }
                }
        }
        return (TRUE);
}


void
mr_update_load_balance_params(MR_FW_RAID_MAP_ALL *map,
    PLD_LOAD_BALANCE_INFO lbInfo)
{
        int ldCount;
        U16 ld;
        MR_LD_RAID *raid;

        for (ldCount = 0; ldCount < MAX_LOGICAL_DRIVES; ldCount++) {
                ld = MR_TargetIdToLdGet(ldCount, map);

                if (ld >= MAX_LOGICAL_DRIVES) {
                        con_log(CL_ANN1,
                            (CE_NOTE, "mrsas: ld=%d Invalid ld \n", ld));
                        continue;
                }

                raid = MR_LdRaidGet(ld, map);

                /* Two drive Optimal RAID 1 */
                if ((raid->level == 1) && (raid->rowSize == 2) &&
                    (raid->spanDepth == 1) &&
                    raid->ldState == MR_LD_STATE_OPTIMAL) {
                        U32 pd, arRef;

                        lbInfo[ldCount].loadBalanceFlag = 1;

                        /* Get the array on which this span is present. */
                        arRef = MR_LdSpanArrayGet(ld, 0, map);

                        pd = MR_ArPdGet(arRef, 0, map);     /* Get the Pd. */
                        /* Get dev handle from Pd. */
                        lbInfo[ldCount].raid1DevHandle[0] =
                            MR_PdDevHandleGet(pd, map);

                        pd = MR_ArPdGet(arRef, 1, map);     /* Get the Pd. */
                        /* Get dev handle from Pd. */
                        lbInfo[ldCount].raid1DevHandle[1] =
                            MR_PdDevHandleGet(pd, map);
                        con_log(CL_ANN1, (CE_NOTE,
                            "mrsas: ld=%d load balancing enabled \n", ldCount));
                } else {
                        lbInfo[ldCount].loadBalanceFlag = 0;
                }
        }
}


U8
megasas_get_best_arm(PLD_LOAD_BALANCE_INFO lbInfo, U8 arm, U64 block,
    U32 count)
{
        U16 pend0, pend1;
        U64 diff0, diff1;
        U8 bestArm;

        /* get the pending cmds for the data and mirror arms */
        pend0 = lbInfo->scsi_pending_cmds[0];
        pend1 = lbInfo->scsi_pending_cmds[1];

        /* Determine the disk whose head is nearer to the req. block */
        diff0 = ABS_DIFF(block, lbInfo->last_accessed_block[0]);
        diff1 = ABS_DIFF(block, lbInfo->last_accessed_block[1]);
        bestArm = (diff0 <= diff1 ? 0 : 1);

        if ((bestArm == arm && pend0 > pend1 + 16) ||
            (bestArm != arm && pend1 > pend0 + 16)) {
                bestArm ^= 1;
        }

        /* Update the last accessed block on the correct pd */
        lbInfo->last_accessed_block[bestArm] = block + count - 1;
        return (bestArm);
}

U16
get_updated_dev_handle(PLD_LOAD_BALANCE_INFO lbInfo,
    struct IO_REQUEST_INFO *io_info)
{
        U8 arm, old_arm;
        U16 devHandle;

        old_arm = lbInfo->raid1DevHandle[0] == io_info->devHandle ? 0 : 1;

        /* get best new arm */
        arm  = megasas_get_best_arm(lbInfo, old_arm, io_info->ldStartBlock,
            io_info->numBlocks);

        devHandle = lbInfo->raid1DevHandle[arm];

        lbInfo->scsi_pending_cmds[arm]++;

        return (devHandle);
}