megaraid_sas_fp.c

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/*
 *  Linux MegaRAID driver for SAS based RAID controllers
 *
 *  Copyright (c) 2009-2012  LSI Corporation.
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version 2
 *  of the License, or (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 *  FILE: megaraid_sas_fp.c
 *
 *  Authors: LSI Corporation
 *           Sumant Patro
 *           Varad Talamacki
 *           Manoj Jose
 *
 *  Send feedback to: <[email protected]>
 *
 *  Mail to: LSI Corporation, 1621 Barber Lane, Milpitas, CA 95035
 *     ATTN: Linuxraid
 */

#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/pci.h>
#include <linux/list.h>
#include <linux/moduleparam.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/uio.h>
#include <linux/uaccess.h>
#include <linux/fs.h>
#include <linux/compat.h>
#include <linux/blkdev.h>
#include <linux/poll.h>

#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>

#include "megaraid_sas_fusion.h"
#include "megaraid_sas.h"
#include <asm/div64.h>

#define ABS_DIFF(a, b)   (((a) > (b)) ? ((a) - (b)) : ((b) - (a)))
#define MR_LD_STATE_OPTIMAL 3
#define FALSE 0
#define TRUE 1

/* Prototypes */
void
mr_update_load_balance_params(struct MR_FW_RAID_MAP_ALL *map,
                  struct LD_LOAD_BALANCE_INFO *lbInfo);

u32 mega_mod64(u64 dividend, u32 divisor)
{
    u64 d;
    u32 remainder;

    if (!divisor)
        printk(KERN_ERR "megasas : DIVISOR is zero, in div fn\n");
    d = dividend;
    remainder = do_div(d, divisor);
    return remainder;
}

u64 mega_div64_32(uint64_t dividend, uint32_t divisor)
{
    u32 remainder;
    u64 d;

    if (!divisor)
        printk(KERN_ERR "megasas : DIVISOR is zero in mod fn\n");

    d = dividend;
    remainder = do_div(d, divisor);

    return d;
}

struct MR_LD_RAID *MR_LdRaidGet(u32 ld, struct MR_FW_RAID_MAP_ALL *map)
{
    return &map->raidMap.ldSpanMap[ld].ldRaid;
}

static struct MR_SPAN_BLOCK_INFO *MR_LdSpanInfoGet(u32 ld,
                           struct MR_FW_RAID_MAP_ALL
                           *map)
{
    return &map->raidMap.ldSpanMap[ld].spanBlock[0];
}

static u8 MR_LdDataArmGet(u32 ld, u32 armIdx, struct MR_FW_RAID_MAP_ALL *map)
{
    return map->raidMap.ldSpanMap[ld].dataArmMap[armIdx];
}

static u16 MR_ArPdGet(u32 ar, u32 arm, struct MR_FW_RAID_MAP_ALL *map)
{
    return map->raidMap.arMapInfo[ar].pd[arm];
}

static u16 MR_LdSpanArrayGet(u32 ld, u32 span, struct MR_FW_RAID_MAP_ALL *map)
{
    return map->raidMap.ldSpanMap[ld].spanBlock[span].span.arrayRef;
}

static u16 MR_PdDevHandleGet(u32 pd, struct MR_FW_RAID_MAP_ALL *map)
{
    return map->raidMap.devHndlInfo[pd].curDevHdl;
}

u16 MR_GetLDTgtId(u32 ld, struct MR_FW_RAID_MAP_ALL *map)
{
    return map->raidMap.ldSpanMap[ld].ldRaid.targetId;
}

u16 MR_TargetIdToLdGet(u32 ldTgtId, struct MR_FW_RAID_MAP_ALL *map)
{
    return map->raidMap.ldTgtIdToLd[ldTgtId];
}

static struct MR_LD_SPAN *MR_LdSpanPtrGet(u32 ld, u32 span,
                      struct 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(struct MR_FW_RAID_MAP_ALL *map,
              struct LD_LOAD_BALANCE_INFO *lbInfo)
{
    struct MR_FW_RAID_MAP *pFwRaidMap = &map->raidMap;

    if (pFwRaidMap->totalSize !=
        (sizeof(struct MR_FW_RAID_MAP) -sizeof(struct MR_LD_SPAN_MAP) +
         (sizeof(struct MR_LD_SPAN_MAP) *pFwRaidMap->ldCount))) {
        printk(KERN_ERR "megasas: map info structure size 0x%x is not matching with ld count\n",
               (unsigned int)((sizeof(struct MR_FW_RAID_MAP) -
                       sizeof(struct MR_LD_SPAN_MAP)) +
                      (sizeof(struct MR_LD_SPAN_MAP) *
                       pFwRaidMap->ldCount)));
        printk(KERN_ERR "megasas: span map %x, pFwRaidMap->totalSize "
               ": %x\n", (unsigned int)sizeof(struct 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,
            struct MR_FW_RAID_MAP_ALL *map, int *div_error)
{
    struct MR_SPAN_BLOCK_INFO *pSpanBlock = MR_LdSpanInfoGet(ld, map);
    struct MR_QUAD_ELEMENT    *quad;
    struct 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++) {
            quad = &pSpanBlock->block_span_info.quad[j];

            if (quad->diff == 0) {
                *div_error = 1;
                return span;
            }
            if (quad->logStart <= row  &&  row <= quad->logEnd  &&
                (mega_mod64(row-quad->logStart, quad->diff)) == 0) {
                if (span_blk != NULL) {
                    u64  blk, debugBlk;
                    blk =
                        mega_div64_32(
                            (row-quad->logStart),
                            quad->diff);
                    debugBlk = blk;

                    blk = (blk + quad->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 megasas_instance *instance, u32 ld, u64 stripRow,
           u16 stripRef, u64 *pdBlock, u16 *pDevHandle,
           struct RAID_CONTEXT *pRAID_Context,
           struct MR_FW_RAID_MAP_ALL *map)
{
    struct MR_LD_RAID  *raid = MR_LdRaidGet(ld, map);
    u32         pd, arRef;
    u8          physArm, span;
    u64         row;
    u8      retval = TRUE;
    int     error_code = 0;

    row =  mega_div64_32(stripRow, raid->rowDataSize);

    if (raid->level == 6) {
        /* logical arm within row */
        u32 logArm =  mega_mod64(stripRow, raid->rowDataSize);
        u32 rowMod, armQ, arm;

        if (raid->rowSize == 0)
            return FALSE;
        /* get logical row mod */
        rowMod = mega_mod64(row, raid->rowSize);
        armQ = raid->rowSize-1-rowMod; /* index of Q drive */
        arm = armQ+1+logArm; /* data always logically follows Q */
        if (arm >= raid->rowSize) /* handle wrap condition */
            arm -= raid->rowSize;
        physArm = (u8)arm;
    } else  {
        if (raid->modFactor == 0)
            return FALSE;
        physArm = MR_LdDataArmGet(ld,  mega_mod64(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);
    pd          = MR_ArPdGet(arRef, physArm, map); /* Get the pd */

    if (pd != MR_PD_INVALID)
        /* Get dev handle from Pd. */
        *pDevHandle = MR_PdDevHandleGet(pd, map);
    else {
        *pDevHandle = MR_PD_INVALID; /* set dev handle as invalid. */
        if ((raid->level >= 5) &&
            ((instance->pdev->device != PCI_DEVICE_ID_LSI_INVADER) ||
             (instance->pdev->device == PCI_DEVICE_ID_LSI_INVADER &&
              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);
            if (pd != MR_PD_INVALID)
                /* Get dev handle from Pd */
                *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 megasas_instance *instance,
            struct IO_REQUEST_INFO *io_info,
            struct RAID_CONTEXT *pRAID_Context,
            struct MR_FW_RAID_MAP_ALL *map)
{
    struct MR_LD_RAID  *raid;
    u32         ld, stripSize, stripe_mask;
    u64         endLba, endStrip, endRow, start_row, start_strip;
    u64         regStart;
    u32         regSize;
    u8          num_strips, numRows;
    u16         ref_in_start_stripe, 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;

    ld = MR_TargetIdToLdGet(ldTgtId, map);
    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); /* End strip */
    if (raid->rowDataSize == 0)
        return FALSE;
    start_row           =  mega_div64_32(start_strip, raid->rowDataSize);
    endRow              =  mega_div64_32(endStrip, raid->rowDataSize);
    numRows             = (u8)(endRow - start_row + 1);

    /*
     * calculate region info.
     */

    /* assume region is at the start of the first row */
    regStart            = start_row << raid->stripeShift;
    /* assume this IO needs the full row - we'll adjust if not true */
    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;

    if (numRows == 1) {
        /* single-strip IOs can always lock only the data needed */
        if (num_strips == 1) {
            regStart += ref_in_start_stripe;
            regSize = numBlocks;
        }
        /* multi-strip IOs always need to full stripe locked */
    } else {
        if (start_strip == (start_row + 1) * raid->rowDataSize - 1) {
            /* If the start strip is the last in the start row */
            regStart += ref_in_start_stripe;
            regSize = stripSize - ref_in_start_stripe;
            /* initialize count to sectors from startref to end
               of strip */
        }

        if (numRows > 2)
            /* Add complete rows in the middle of the transfer */
            regSize += (numRows-2) << raid->stripeShift;

        /* if IO ends within first strip of last row */
        if (endStrip == endRow*raid->rowDataSize)
            regSize += ref_in_end_stripe+1;
        else
            regSize += stripSize;
    }

    pRAID_Context->timeoutValue     = map->raidMap.fpPdIoTimeoutSec;
    if (instance->pdev->device == PCI_DEVICE_ID_LSI_INVADER)
        pRAID_Context->regLockFlags = (isRead) ?
            raid->regTypeReqOnRead : raid->regTypeReqOnWrite;
    else
        pRAID_Context->regLockFlags = (isRead) ?
            REGION_TYPE_SHARED_READ : raid->regTypeReqOnWrite;
    pRAID_Context->VirtualDiskTgtId = 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) {
        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 i snot possible */
        if (io_info->devHandle == MR_PD_INVALID)
            io_info->fpOkForIo = FALSE;
        return retval;
    } else if (isRead) {
        uint 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(struct MR_FW_RAID_MAP_ALL *map,
                  struct LD_LOAD_BALANCE_INFO *lbInfo)
{
    int ldCount;
    u16 ld;
    struct MR_LD_RAID *raid;

    for (ldCount = 0; ldCount < MAX_LOGICAL_DRIVES; ldCount++) {
        ld = MR_TargetIdToLdGet(ldCount, map);
        if (ld >= MAX_LOGICAL_DRIVES) {
            lbInfo[ldCount].loadBalanceFlag = 0;
            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);

            /* Get the Pd */
            pd = MR_ArPdGet(arRef, 0, map);
            /* Get dev handle from Pd */
            lbInfo[ldCount].raid1DevHandle[0] =
                MR_PdDevHandleGet(pd, map);
            /* Get the Pd */
            pd = MR_ArPdGet(arRef, 1, map);

            /* Get the dev handle from Pd */
            lbInfo[ldCount].raid1DevHandle[1] =
                MR_PdDevHandleGet(pd, map);
        } else
            lbInfo[ldCount].loadBalanceFlag = 0;
    }
}

u8 megasas_get_best_arm(struct LD_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 = atomic_read(&lbInfo->scsi_pending_cmds[0]);
    pend1 = atomic_read(&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(struct LD_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];
    atomic_inc(&lbInfo->scsi_pending_cmds[arm]);

    return devHandle;
}