Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1361 insertions, 0 deletions

diff --git a/drivers/scsi/megaraid/megaraid_sas_fp.c b/drivers/scsi/megaraid/megaraid_sas_fp.c
new file mode 100644
index 000000000..a33628550
--- /dev/null
+++ b/drivers/scsi/megaraid/megaraid_sas_fp.c
@@ -0,0 +1,1361 @@
+/*
+ *  Linux MegaRAID driver for SAS based RAID controllers
+ *
+ *  Copyright (c) 2009-2013  LSI Corporation
+ *  Copyright (c) 2013-2014  Avago Technologies
+ *
+ *  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, see <http://www.gnu.org/licenses/>.
+ *
+ *  FILE: megaraid_sas_fp.c
+ *
+ *  Authors: Avago Technologies
+ *           Sumant Patro
+ *           Varad Talamacki
+ *           Manoj Jose
+ *           Kashyap Desai <kashyap.desai@avagotech.com>
+ *           Sumit Saxena <sumit.saxena@avagotech.com>
+ *
+ *  Send feedback to: megaraidlinux.pdl@avagotech.com
+ *
+ *  Mail to: Avago Technologies, 350 West Trimble Road, Building 90,
+ *  San Jose, California 95131
+ */
+
+#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 LB_PENDING_CMDS_DEFAULT 4
+static unsigned int lb_pending_cmds = LB_PENDING_CMDS_DEFAULT;
+module_param(lb_pending_cmds, int, S_IRUGO);
+MODULE_PARM_DESC(lb_pending_cmds, "Change raid-1 load balancing outstanding "
+	"threshold. Valid Values are 1-128. Default: 4");
+
+
+#define ABS_DIFF(a, b)   (((a) > (b)) ? ((a) - (b)) : ((b) - (a)))
+#define MR_LD_STATE_OPTIMAL 3
+
+#define SPAN_ROW_SIZE(map, ld, index_) (MR_LdSpanPtrGet(ld, index_, map)->spanRowSize)
+#define SPAN_ROW_DATA_SIZE(map_, ld, index_)   (MR_LdSpanPtrGet(ld, index_, map)->spanRowDataSize)
+#define SPAN_INVALID  0xff
+
+/* Prototypes */
+static void mr_update_span_set(struct MR_DRV_RAID_MAP_ALL *map,
+	PLD_SPAN_INFO ldSpanInfo);
+static u8 mr_spanset_get_phy_params(struct megasas_instance *instance, u32 ld,
+	u64 stripRow, u16 stripRef, struct IO_REQUEST_INFO *io_info,
+	struct RAID_CONTEXT *pRAID_Context, struct MR_DRV_RAID_MAP_ALL *map);
+static u64 get_row_from_strip(struct megasas_instance *instance, u32 ld,
+	u64 strip, struct MR_DRV_RAID_MAP_ALL *map);
+
+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;
+}
+
+/**
+ * @param dividend    : Dividend
+ * @param divisor    : Divisor
+ *
+ * @return quotient
+ **/
+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_DRV_RAID_MAP_ALL *map)
+{
+	return &map->raidMap.ldSpanMap[ld].ldRaid;
+}
+
+static struct MR_SPAN_BLOCK_INFO *MR_LdSpanInfoGet(u32 ld,
+						   struct MR_DRV_RAID_MAP_ALL
+						   *map)
+{
+	return &map->raidMap.ldSpanMap[ld].spanBlock[0];
+}
+
+static u8 MR_LdDataArmGet(u32 ld, u32 armIdx, struct MR_DRV_RAID_MAP_ALL *map)
+{
+	return map->raidMap.ldSpanMap[ld].dataArmMap[armIdx];
+}
+
+u16 MR_ArPdGet(u32 ar, u32 arm, struct MR_DRV_RAID_MAP_ALL *map)
+{
+	return le16_to_cpu(map->raidMap.arMapInfo[ar].pd[arm]);
+}
+
+u16 MR_LdSpanArrayGet(u32 ld, u32 span, struct MR_DRV_RAID_MAP_ALL *map)
+{
+	return le16_to_cpu(map->raidMap.ldSpanMap[ld].spanBlock[span].span.arrayRef);
+}
+
+__le16 MR_PdDevHandleGet(u32 pd, struct MR_DRV_RAID_MAP_ALL *map)
+{
+	return map->raidMap.devHndlInfo[pd].curDevHdl;
+}
+
+static u8 MR_PdInterfaceTypeGet(u32 pd, struct MR_DRV_RAID_MAP_ALL *map)
+{
+	return map->raidMap.devHndlInfo[pd].interfaceType;
+}
+
+u16 MR_GetLDTgtId(u32 ld, struct MR_DRV_RAID_MAP_ALL *map)
+{
+	return le16_to_cpu(map->raidMap.ldSpanMap[ld].ldRaid.targetId);
+}
+
+u16 MR_TargetIdToLdGet(u32 ldTgtId, struct MR_DRV_RAID_MAP_ALL *map)
+{
+	return map->raidMap.ldTgtIdToLd[ldTgtId];
+}
+
+static struct MR_LD_SPAN *MR_LdSpanPtrGet(u32 ld, u32 span,
+					  struct MR_DRV_RAID_MAP_ALL *map)
+{
+	return &map->raidMap.ldSpanMap[ld].spanBlock[span].span;
+}
+
+/*
+ * This function will Populate Driver Map using firmware raid map
+ */
+static int MR_PopulateDrvRaidMap(struct megasas_instance *instance, u64 map_id)
+{
+	struct fusion_context *fusion = instance->ctrl_context;
+	struct MR_FW_RAID_MAP_ALL     *fw_map_old    = NULL;
+	struct MR_FW_RAID_MAP         *pFwRaidMap    = NULL;
+	int i, j;
+	u16 ld_count;
+	struct MR_FW_RAID_MAP_DYNAMIC *fw_map_dyn;
+	struct MR_FW_RAID_MAP_EXT *fw_map_ext;
+	struct MR_RAID_MAP_DESC_TABLE *desc_table;
+
+
+	struct MR_DRV_RAID_MAP_ALL *drv_map =
+			fusion->ld_drv_map[(map_id & 1)];
+	struct MR_DRV_RAID_MAP *pDrvRaidMap = &drv_map->raidMap;
+	void *raid_map_data = NULL;
+
+	memset(drv_map, 0, fusion->drv_map_sz);
+	memset(pDrvRaidMap->ldTgtIdToLd,
+	       0xff, (sizeof(u16) * MAX_LOGICAL_DRIVES_DYN));
+
+	if (instance->max_raid_mapsize) {
+		fw_map_dyn = fusion->ld_map[(map_id & 1)];
+		desc_table =
+		(struct MR_RAID_MAP_DESC_TABLE *)((void *)fw_map_dyn + le32_to_cpu(fw_map_dyn->desc_table_offset));
+		if (desc_table != fw_map_dyn->raid_map_desc_table)
+			dev_dbg(&instance->pdev->dev, "offsets of desc table are not matching desc %p original %p\n",
+				desc_table, fw_map_dyn->raid_map_desc_table);
+
+		ld_count = (u16)le16_to_cpu(fw_map_dyn->ld_count);
+		pDrvRaidMap->ldCount = (__le16)cpu_to_le16(ld_count);
+		pDrvRaidMap->fpPdIoTimeoutSec =
+			fw_map_dyn->fp_pd_io_timeout_sec;
+		pDrvRaidMap->totalSize =
+			cpu_to_le32(sizeof(struct MR_DRV_RAID_MAP_ALL));
+		/* point to actual data starting point*/
+		raid_map_data = (void *)fw_map_dyn +
+			le32_to_cpu(fw_map_dyn->desc_table_offset) +
+			le32_to_cpu(fw_map_dyn->desc_table_size);
+
+		for (i = 0; i < le32_to_cpu(fw_map_dyn->desc_table_num_elements); ++i) {
+			switch (le32_to_cpu(desc_table->raid_map_desc_type)) {
+			case RAID_MAP_DESC_TYPE_DEVHDL_INFO:
+				fw_map_dyn->dev_hndl_info =
+				(struct MR_DEV_HANDLE_INFO *)(raid_map_data + le32_to_cpu(desc_table->raid_map_desc_offset));
+				memcpy(pDrvRaidMap->devHndlInfo,
+					fw_map_dyn->dev_hndl_info,
+					sizeof(struct MR_DEV_HANDLE_INFO) *
+					le32_to_cpu(desc_table->raid_map_desc_elements));
+			break;
+			case RAID_MAP_DESC_TYPE_TGTID_INFO:
+				fw_map_dyn->ld_tgt_id_to_ld =
+					(u16 *)(raid_map_data +
+					le32_to_cpu(desc_table->raid_map_desc_offset));
+				for (j = 0; j < le32_to_cpu(desc_table->raid_map_desc_elements); j++) {
+					pDrvRaidMap->ldTgtIdToLd[j] =
+						le16_to_cpu(fw_map_dyn->ld_tgt_id_to_ld[j]);
+				}
+			break;
+			case RAID_MAP_DESC_TYPE_ARRAY_INFO:
+				fw_map_dyn->ar_map_info =
+					(struct MR_ARRAY_INFO *)
+					(raid_map_data + le32_to_cpu(desc_table->raid_map_desc_offset));
+				memcpy(pDrvRaidMap->arMapInfo,
+				       fw_map_dyn->ar_map_info,
+				       sizeof(struct MR_ARRAY_INFO) *
+				       le32_to_cpu(desc_table->raid_map_desc_elements));
+			break;
+			case RAID_MAP_DESC_TYPE_SPAN_INFO:
+				fw_map_dyn->ld_span_map =
+					(struct MR_LD_SPAN_MAP *)
+					(raid_map_data +
+					le32_to_cpu(desc_table->raid_map_desc_offset));
+				memcpy(pDrvRaidMap->ldSpanMap,
+				       fw_map_dyn->ld_span_map,
+				       sizeof(struct MR_LD_SPAN_MAP) *
+				       le32_to_cpu(desc_table->raid_map_desc_elements));
+			break;
+			default:
+				dev_dbg(&instance->pdev->dev, "wrong number of desctableElements %d\n",
+					fw_map_dyn->desc_table_num_elements);
+			}
+			++desc_table;
+		}
+
+	} else if (instance->supportmax256vd) {
+		fw_map_ext =
+			(struct MR_FW_RAID_MAP_EXT *)fusion->ld_map[(map_id & 1)];
+		ld_count = (u16)le16_to_cpu(fw_map_ext->ldCount);
+		if (ld_count > MAX_LOGICAL_DRIVES_EXT) {
+			dev_dbg(&instance->pdev->dev, "megaraid_sas: LD count exposed in RAID map in not valid\n");
+			return 1;
+		}
+
+		pDrvRaidMap->ldCount = (__le16)cpu_to_le16(ld_count);
+		pDrvRaidMap->fpPdIoTimeoutSec = fw_map_ext->fpPdIoTimeoutSec;
+		for (i = 0; i < (MAX_LOGICAL_DRIVES_EXT); i++)
+			pDrvRaidMap->ldTgtIdToLd[i] =
+				(u16)fw_map_ext->ldTgtIdToLd[i];
+		memcpy(pDrvRaidMap->ldSpanMap, fw_map_ext->ldSpanMap,
+		       sizeof(struct MR_LD_SPAN_MAP) * ld_count);
+		memcpy(pDrvRaidMap->arMapInfo, fw_map_ext->arMapInfo,
+		       sizeof(struct MR_ARRAY_INFO) * MAX_API_ARRAYS_EXT);
+		memcpy(pDrvRaidMap->devHndlInfo, fw_map_ext->devHndlInfo,
+		       sizeof(struct MR_DEV_HANDLE_INFO) *
+		       MAX_RAIDMAP_PHYSICAL_DEVICES);
+
+		/* New Raid map will not set totalSize, so keep expected value
+		 * for legacy code in ValidateMapInfo
+		 */
+		pDrvRaidMap->totalSize =
+			cpu_to_le32(sizeof(struct MR_FW_RAID_MAP_EXT));
+	} else {
+		fw_map_old = (struct MR_FW_RAID_MAP_ALL *)
+				fusion->ld_map[(map_id & 1)];
+		pFwRaidMap = &fw_map_old->raidMap;
+		ld_count = (u16)le32_to_cpu(pFwRaidMap->ldCount);
+		if (ld_count > MAX_LOGICAL_DRIVES) {
+			dev_dbg(&instance->pdev->dev,
+				"LD count exposed in RAID map in not valid\n");
+			return 1;
+		}
+
+		pDrvRaidMap->totalSize = pFwRaidMap->totalSize;
+		pDrvRaidMap->ldCount = (__le16)cpu_to_le16(ld_count);
+		pDrvRaidMap->fpPdIoTimeoutSec = pFwRaidMap->fpPdIoTimeoutSec;
+		for (i = 0; i < MAX_RAIDMAP_LOGICAL_DRIVES + MAX_RAIDMAP_VIEWS; i++)
+			pDrvRaidMap->ldTgtIdToLd[i] =
+				(u8)pFwRaidMap->ldTgtIdToLd[i];
+		for (i = 0; i < ld_count; i++) {
+			pDrvRaidMap->ldSpanMap[i] = pFwRaidMap->ldSpanMap[i];
+		}
+		memcpy(pDrvRaidMap->arMapInfo, pFwRaidMap->arMapInfo,
+			sizeof(struct MR_ARRAY_INFO) * MAX_RAIDMAP_ARRAYS);
+		memcpy(pDrvRaidMap->devHndlInfo, pFwRaidMap->devHndlInfo,
+			sizeof(struct MR_DEV_HANDLE_INFO) *
+			MAX_RAIDMAP_PHYSICAL_DEVICES);
+	}
+
+	return 0;
+}
+
+/*
+ * This function will validate Map info data provided by FW
+ */
+u8 MR_ValidateMapInfo(struct megasas_instance *instance, u64 map_id)
+{
+	struct fusion_context *fusion;
+	struct MR_DRV_RAID_MAP_ALL *drv_map;
+	struct MR_DRV_RAID_MAP *pDrvRaidMap;
+	struct LD_LOAD_BALANCE_INFO *lbInfo;
+	PLD_SPAN_INFO ldSpanInfo;
+	struct MR_LD_RAID         *raid;
+	u16 num_lds, i;
+	u16 ld;
+	u32 expected_size;
+
+	if (MR_PopulateDrvRaidMap(instance, map_id))
+		return 0;
+
+	fusion = instance->ctrl_context;
+	drv_map = fusion->ld_drv_map[(map_id & 1)];
+	pDrvRaidMap = &drv_map->raidMap;
+
+	lbInfo = fusion->load_balance_info;
+	ldSpanInfo = fusion->log_to_span;
+
+	if (instance->max_raid_mapsize)
+		expected_size = sizeof(struct MR_DRV_RAID_MAP_ALL);
+	else if (instance->supportmax256vd)
+		expected_size = sizeof(struct MR_FW_RAID_MAP_EXT);
+	else
+		expected_size =
+			(sizeof(struct MR_FW_RAID_MAP) - sizeof(struct MR_LD_SPAN_MAP) +
+			(sizeof(struct MR_LD_SPAN_MAP) * le16_to_cpu(pDrvRaidMap->ldCount)));
+
+	if (le32_to_cpu(pDrvRaidMap->totalSize) != expected_size) {
+		dev_dbg(&instance->pdev->dev, "megasas: map info structure size 0x%x",
+			le32_to_cpu(pDrvRaidMap->totalSize));
+		dev_dbg(&instance->pdev->dev, "is not matching expected size 0x%x\n",
+			(unsigned int)expected_size);
+		dev_err(&instance->pdev->dev, "megasas: span map %x, pDrvRaidMap->totalSize : %x\n",
+			(unsigned int)sizeof(struct MR_LD_SPAN_MAP),
+			le32_to_cpu(pDrvRaidMap->totalSize));
+		return 0;
+	}
+
+	if (instance->UnevenSpanSupport)
+		mr_update_span_set(drv_map, ldSpanInfo);
+
+	if (lbInfo)
+		mr_update_load_balance_params(drv_map, lbInfo);
+
+	num_lds = le16_to_cpu(drv_map->raidMap.ldCount);
+
+	/*Convert Raid capability values to CPU arch */
+	for (i = 0; (num_lds > 0) && (i < MAX_LOGICAL_DRIVES_EXT); i++) {
+		ld = MR_TargetIdToLdGet(i, drv_map);
+
+		/* For non existing VDs, iterate to next VD*/
+		if (ld >= (MAX_LOGICAL_DRIVES_EXT - 1))
+			continue;
+
+		raid = MR_LdRaidGet(ld, drv_map);
+		le32_to_cpus((u32 *)&raid->capability);
+
+		num_lds--;
+	}
+
+	return 1;
+}
+
+u32 MR_GetSpanBlock(u32 ld, u64 row, u64 *span_blk,
+		    struct MR_DRV_RAID_MAP_ALL *map)
+{
+	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 < le32_to_cpu(pSpanBlock->block_span_info.noElements); j++) {
+			quad = &pSpanBlock->block_span_info.quad[j];
+
+			if (le32_to_cpu(quad->diff) == 0)
+				return SPAN_INVALID;
+			if (le64_to_cpu(quad->logStart) <= row && row <=
+				le64_to_cpu(quad->logEnd) && (mega_mod64(row - le64_to_cpu(quad->logStart),
+				le32_to_cpu(quad->diff))) == 0) {
+				if (span_blk != NULL) {
+					u64  blk, debugBlk;
+					blk =  mega_div64_32((row-le64_to_cpu(quad->logStart)), le32_to_cpu(quad->diff));
+					debugBlk = blk;
+
+					blk = (blk + le64_to_cpu(quad->offsetInSpan)) << raid->stripeShift;
+					*span_blk = blk;
+				}
+				return span;
+			}
+		}
+	}
+	return SPAN_INVALID;
+}
+
+/*
+******************************************************************************
+*
+* This routine calculates the Span block for given row using spanset.
+*
+* Inputs :
+*    instance - HBA instance
+*    ld   - Logical drive number
+*    row        - Row number
+*    map    - LD map
+*
+* Outputs :
+*
+*    span          - Span number
+*    block         - Absolute Block number in the physical disk
+*    div_error	   - Devide error code.
+*/
+
+u32 mr_spanset_get_span_block(struct megasas_instance *instance,
+		u32 ld, u64 row, u64 *span_blk, struct MR_DRV_RAID_MAP_ALL *map)
+{
+	struct fusion_context *fusion = instance->ctrl_context;
+	struct MR_LD_RAID         *raid = MR_LdRaidGet(ld, map);
+	LD_SPAN_SET *span_set;
+	struct MR_QUAD_ELEMENT    *quad;
+	u32    span, info;
+	PLD_SPAN_INFO ldSpanInfo = fusion->log_to_span;
+
+	for (info = 0; info < MAX_QUAD_DEPTH; info++) {
+		span_set = &(ldSpanInfo[ld].span_set[info]);
+
+		if (span_set->span_row_data_width == 0)
+			break;
+
+		if (row > span_set->data_row_end)
+			continue;
+
+		for (span = 0; span < raid->spanDepth; span++)
+			if (le32_to_cpu(map->raidMap.ldSpanMap[ld].spanBlock[span].
+				block_span_info.noElements) >= info+1) {
+				quad = &map->raidMap.ldSpanMap[ld].
+					spanBlock[span].
+					block_span_info.quad[info];
+				if (le32_to_cpu(quad->diff) == 0)
+					return SPAN_INVALID;
+				if (le64_to_cpu(quad->logStart) <= row  &&
+					row <= le64_to_cpu(quad->logEnd)  &&
+					(mega_mod64(row - le64_to_cpu(quad->logStart),
+						le32_to_cpu(quad->diff))) == 0) {
+					if (span_blk != NULL) {
+						u64  blk;
+						blk = mega_div64_32
+						    ((row - le64_to_cpu(quad->logStart)),
+						    le32_to_cpu(quad->diff));
+						blk = (blk + le64_to_cpu(quad->offsetInSpan))
+							 << raid->stripeShift;
+						*span_blk = blk;
+					}
+					return span;
+				}
+			}
+	}
+	return SPAN_INVALID;
+}
+
+/*
+******************************************************************************
+*
+* This routine calculates the row for given strip using spanset.
+*
+* Inputs :
+*    instance - HBA instance
+*    ld   - Logical drive number
+*    Strip        - Strip
+*    map    - LD map
+*
+* Outputs :
+*
+*    row         - row associated with strip
+*/
+
+static u64  get_row_from_strip(struct megasas_instance *instance,
+	u32 ld, u64 strip, struct MR_DRV_RAID_MAP_ALL *map)
+{
+	struct fusion_context *fusion = instance->ctrl_context;
+	struct MR_LD_RAID	*raid = MR_LdRaidGet(ld, map);
+	LD_SPAN_SET	*span_set;
+	PLD_SPAN_INFO	ldSpanInfo = fusion->log_to_span;
+	u32		info, strip_offset, span, span_offset;
+	u64		span_set_Strip, span_set_Row, retval;
+
+	for (info = 0; info < MAX_QUAD_DEPTH; info++) {
+		span_set = &(ldSpanInfo[ld].span_set[info]);
+
+		if (span_set->span_row_data_width == 0)
+			break;
+		if (strip > span_set->data_strip_end)
+			continue;
+
+		span_set_Strip = strip - span_set->data_strip_start;
+		strip_offset = mega_mod64(span_set_Strip,
+				span_set->span_row_data_width);
+		span_set_Row = mega_div64_32(span_set_Strip,
+				span_set->span_row_data_width) * span_set->diff;
+		for (span = 0, span_offset = 0; span < raid->spanDepth; span++)
+			if (le32_to_cpu(map->raidMap.ldSpanMap[ld].spanBlock[span].
+				block_span_info.noElements) >= info+1) {
+				if (strip_offset >=
+					span_set->strip_offset[span])
+					span_offset++;
+				else
+					break;
+			}
+
+		retval = (span_set->data_row_start + span_set_Row +
+				(span_offset - 1));
+		return retval;
+	}
+	return -1LLU;
+}
+
+
+/*
+******************************************************************************
+*
+* This routine calculates the Start Strip for given row using spanset.
+*
+* Inputs :
+*    instance - HBA instance
+*    ld   - Logical drive number
+*    row        - Row number
+*    map    - LD map
+*
+* Outputs :
+*
+*    Strip         - Start strip associated with row
+*/
+
+static u64 get_strip_from_row(struct megasas_instance *instance,
+		u32 ld, u64 row, struct MR_DRV_RAID_MAP_ALL *map)
+{
+	struct fusion_context *fusion = instance->ctrl_context;
+	struct MR_LD_RAID         *raid = MR_LdRaidGet(ld, map);
+	LD_SPAN_SET *span_set;
+	struct MR_QUAD_ELEMENT    *quad;
+	PLD_SPAN_INFO ldSpanInfo = fusion->log_to_span;
+	u32    span, info;
+	u64  strip;
+
+	for (info = 0; info < MAX_QUAD_DEPTH; info++) {
+		span_set = &(ldSpanInfo[ld].span_set[info]);
+
+		if (span_set->span_row_data_width == 0)
+			break;
+		if (row > span_set->data_row_end)
+			continue;
+
+		for (span = 0; span < raid->spanDepth; span++)
+			if (le32_to_cpu(map->raidMap.ldSpanMap[ld].spanBlock[span].
+				block_span_info.noElements) >= info+1) {
+				quad = &map->raidMap.ldSpanMap[ld].
+					spanBlock[span].block_span_info.quad[info];
+				if (le64_to_cpu(quad->logStart) <= row  &&
+					row <= le64_to_cpu(quad->logEnd)  &&
+					mega_mod64((row - le64_to_cpu(quad->logStart)),
+					le32_to_cpu(quad->diff)) == 0) {
+					strip = mega_div64_32
+						(((row - span_set->data_row_start)
+							- le64_to_cpu(quad->logStart)),
+							le32_to_cpu(quad->diff));
+					strip *= span_set->span_row_data_width;
+					strip += span_set->data_strip_start;
+					strip += span_set->strip_offset[span];
+					return strip;
+				}
+			}
+	}
+	dev_err(&instance->pdev->dev, "get_strip_from_row"
+		"returns invalid strip for ld=%x, row=%lx\n",
+		ld, (long unsigned int)row);
+	return -1;
+}
+
+/*
+******************************************************************************
+*
+* This routine calculates the Physical Arm for given strip using spanset.
+*
+* Inputs :
+*    instance - HBA instance
+*    ld   - Logical drive number
+*    strip      - Strip
+*    map    - LD map
+*
+* Outputs :
+*
+*    Phys Arm         - Phys Arm associated with strip
+*/
+
+static u32 get_arm_from_strip(struct megasas_instance *instance,
+	u32 ld, u64 strip, struct MR_DRV_RAID_MAP_ALL *map)
+{
+	struct fusion_context *fusion = instance->ctrl_context;
+	struct MR_LD_RAID         *raid = MR_LdRaidGet(ld, map);
+	LD_SPAN_SET *span_set;
+	PLD_SPAN_INFO ldSpanInfo = fusion->log_to_span;
+	u32    info, strip_offset, span, span_offset, retval;
+
+	for (info = 0 ; info < MAX_QUAD_DEPTH; info++) {
+		span_set = &(ldSpanInfo[ld].span_set[info]);
+
+		if (span_set->span_row_data_width == 0)
+			break;
+		if (strip > span_set->data_strip_end)
+			continue;
+
+		strip_offset = (uint)mega_mod64
+				((strip - span_set->data_strip_start),
+				span_set->span_row_data_width);
+
+		for (span = 0, span_offset = 0; span < raid->spanDepth; span++)
+			if (le32_to_cpu(map->raidMap.ldSpanMap[ld].spanBlock[span].
+				block_span_info.noElements) >= info+1) {
+				if (strip_offset >=
+					span_set->strip_offset[span])
+					span_offset =
+						span_set->strip_offset[span];
+				else
+					break;
+			}
+
+		retval = (strip_offset - span_offset);
+		return retval;
+	}
+
+	dev_err(&instance->pdev->dev, "get_arm_from_strip"
+		"returns invalid arm for ld=%x strip=%lx\n",
+		ld, (long unsigned int)strip);
+
+	return -1;
+}
+
+/* This Function will return Phys arm */
+u8 get_arm(struct megasas_instance *instance, u32 ld, u8 span, u64 stripe,
+		struct MR_DRV_RAID_MAP_ALL *map)
+{
+	struct MR_LD_RAID  *raid = MR_LdRaidGet(ld, map);
+	/* Need to check correct default value */
+	u32    arm = 0;
+
+	switch (raid->level) {
+	case 0:
+	case 5:
+	case 6:
+		arm = mega_mod64(stripe, SPAN_ROW_SIZE(map, ld, span));
+		break;
+	case 1:
+		/* start with logical arm */
+		arm = get_arm_from_strip(instance, ld, stripe, map);
+		if (arm != -1U)
+			arm *= 2;
+		break;
+	}
+
+	return arm;
+}
+
+
+/*
+******************************************************************************
+*
+* This routine calculates the arm, span and block for the specified stripe and
+* reference in stripe using spanset
+*
+* Inputs :
+*
+*    ld   - Logical drive number
+*    stripRow        - Stripe number
+*    stripRef    - Reference in stripe
+*
+* Outputs :
+*
+*    span          - Span number
+*    block         - Absolute Block number in the physical disk
+*/
+static u8 mr_spanset_get_phy_params(struct megasas_instance *instance, u32 ld,
+		u64 stripRow, u16 stripRef, struct IO_REQUEST_INFO *io_info,
+		struct RAID_CONTEXT *pRAID_Context,
+		struct MR_DRV_RAID_MAP_ALL *map)
+{
+	struct MR_LD_RAID  *raid = MR_LdRaidGet(ld, map);
+	u32     pd, arRef, r1_alt_pd;
+	u8      physArm, span;
+	u64     row;
+	u8	retval = true;
+	u64	*pdBlock = &io_info->pdBlock;
+	__le16	*pDevHandle = &io_info->devHandle;
+	u8	*pPdInterface = &io_info->pd_interface;
+	u32	logArm, rowMod, armQ, arm;
+	struct fusion_context *fusion;
+
+	fusion = instance->ctrl_context;
+	*pDevHandle = cpu_to_le16(MR_DEVHANDLE_INVALID);
+
+	/*Get row and span from io_info for Uneven Span IO.*/
+	row	    = io_info->start_row;
+	span	    = io_info->start_span;
+
+
+	if (raid->level == 6) {
+		logArm = get_arm_from_strip(instance, ld, stripRow, map);
+		if (logArm == -1U)
+			return false;
+		rowMod = mega_mod64(row, SPAN_ROW_SIZE(map, ld, span));
+		armQ = SPAN_ROW_SIZE(map, ld, span) - 1 - rowMod;
+		arm = armQ + 1 + logArm;
+		if (arm >= SPAN_ROW_SIZE(map, ld, span))
+			arm -= SPAN_ROW_SIZE(map, ld, span);
+		physArm = (u8)arm;
+	} else
+		/* Calculate the arm */
+		physArm = get_arm(instance, ld, span, stripRow, map);
+	if (physArm == 0xFF)
+		return false;
+
+	arRef       = MR_LdSpanArrayGet(ld, span, map);
+	pd          = MR_ArPdGet(arRef, physArm, map);
+
+	if (pd != MR_PD_INVALID) {
+		*pDevHandle = MR_PdDevHandleGet(pd, map);
+		*pPdInterface = MR_PdInterfaceTypeGet(pd, map);
+		/* get second pd also for raid 1/10 fast path writes*/
+		if ((instance->adapter_type == VENTURA_SERIES) &&
+		    (raid->level == 1) &&
+		    !io_info->isRead) {
+			r1_alt_pd = MR_ArPdGet(arRef, physArm + 1, map);
+			if (r1_alt_pd != MR_PD_INVALID)
+				io_info->r1_alt_dev_handle =
+				MR_PdDevHandleGet(r1_alt_pd, map);
+		}
+	} else {
+		if ((raid->level >= 5) &&
+			((instance->adapter_type == THUNDERBOLT_SERIES)  ||
+			((instance->adapter_type == INVADER_SERIES) &&
+			(raid->regTypeReqOnRead != REGION_TYPE_UNUSED))))
+			pRAID_Context->reg_lock_flags = REGION_TYPE_EXCLUSIVE;
+		else if (raid->level == 1) {
+			physArm = physArm + 1;
+			pd = MR_ArPdGet(arRef, physArm, map);
+			if (pd != MR_PD_INVALID) {
+				*pDevHandle = MR_PdDevHandleGet(pd, map);
+				*pPdInterface = MR_PdInterfaceTypeGet(pd, map);
+			}
+		}
+	}
+
+	*pdBlock += stripRef + le64_to_cpu(MR_LdSpanPtrGet(ld, span, map)->startBlk);
+	if (instance->adapter_type == VENTURA_SERIES) {
+		((struct RAID_CONTEXT_G35 *)pRAID_Context)->span_arm =
+			(span << RAID_CTX_SPANARM_SPAN_SHIFT) | physArm;
+		io_info->span_arm =
+			(span << RAID_CTX_SPANARM_SPAN_SHIFT) | physArm;
+	} else {
+		pRAID_Context->span_arm =
+			(span << RAID_CTX_SPANARM_SPAN_SHIFT) | physArm;
+		io_info->span_arm = pRAID_Context->span_arm;
+	}
+	io_info->pd_after_lb = pd;
+	return retval;
+}
+
+/*
+******************************************************************************
+*
+* 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, struct IO_REQUEST_INFO *io_info,
+		struct RAID_CONTEXT *pRAID_Context,
+		struct MR_DRV_RAID_MAP_ALL *map)
+{
+	struct MR_LD_RAID  *raid = MR_LdRaidGet(ld, map);
+	u32         pd, arRef, r1_alt_pd;
+	u8          physArm, span;
+	u64         row;
+	u8	    retval = true;
+	u64	    *pdBlock = &io_info->pdBlock;
+	__le16	    *pDevHandle = &io_info->devHandle;
+	u8	    *pPdInterface = &io_info->pd_interface;
+	struct fusion_context *fusion;
+
+	fusion = instance->ctrl_context;
+	*pDevHandle = cpu_to_le16(MR_DEVHANDLE_INVALID);
+
+	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);
+		if (span == SPAN_INVALID)
+			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);
+		*pPdInterface = MR_PdInterfaceTypeGet(pd, map);
+		/* get second pd also for raid 1/10 fast path writes*/
+		if ((instance->adapter_type == VENTURA_SERIES) &&
+		    (raid->level == 1) &&
+		    !io_info->isRead) {
+			r1_alt_pd = MR_ArPdGet(arRef, physArm + 1, map);
+			if (r1_alt_pd != MR_PD_INVALID)
+				io_info->r1_alt_dev_handle =
+					MR_PdDevHandleGet(r1_alt_pd, map);
+		}
+	} else {
+		if ((raid->level >= 5) &&
+			((instance->adapter_type == THUNDERBOLT_SERIES)  ||
+			((instance->adapter_type == INVADER_SERIES) &&
+			(raid->regTypeReqOnRead != REGION_TYPE_UNUSED))))
+			pRAID_Context->reg_lock_flags = REGION_TYPE_EXCLUSIVE;
+		else if (raid->level == 1) {
+			/* Get alternate Pd. */
+			physArm = physArm + 1;
+			pd = MR_ArPdGet(arRef, physArm, map);
+			if (pd != MR_PD_INVALID) {
+				/* Get dev handle from Pd */
+				*pDevHandle = MR_PdDevHandleGet(pd, map);
+				*pPdInterface = MR_PdInterfaceTypeGet(pd, map);
+			}
+		}
+	}
+
+	*pdBlock += stripRef + le64_to_cpu(MR_LdSpanPtrGet(ld, span, map)->startBlk);
+	if (instance->adapter_type == VENTURA_SERIES) {
+		((struct RAID_CONTEXT_G35 *)pRAID_Context)->span_arm =
+				(span << RAID_CTX_SPANARM_SPAN_SHIFT) | physArm;
+		io_info->span_arm =
+				(span << RAID_CTX_SPANARM_SPAN_SHIFT) | physArm;
+	} else {
+		pRAID_Context->span_arm =
+			(span << RAID_CTX_SPANARM_SPAN_SHIFT) | physArm;
+		io_info->span_arm = pRAID_Context->span_arm;
+	}
+	io_info->pd_after_lb = pd;
+	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_DRV_RAID_MAP_ALL *map, u8 **raidLUN)
+{
+	struct fusion_context *fusion;
+	struct MR_LD_RAID  *raid;
+	u32         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;
+	u8	    startlba_span = SPAN_INVALID;
+	u64 *pdBlock = &io_info->pdBlock;
+	u16	    ld;
+
+	ldStartBlock = io_info->ldStartBlock;
+	numBlocks = io_info->numBlocks;
+	ldTgtId = io_info->ldTgtId;
+	isRead = io_info->isRead;
+	io_info->IoforUnevenSpan = 0;
+	io_info->start_span	= SPAN_INVALID;
+	fusion = instance->ctrl_context;
+
+	ld = MR_TargetIdToLdGet(ldTgtId, map);
+	raid = MR_LdRaidGet(ld, map);
+	/*check read ahead bit*/
+	io_info->ra_capable = raid->capability.ra_capable;
+
+	/*
+	 * if rowDataSize @RAID map and spanRowDataSize @SPAN INFO are zero
+	 * return FALSE
+	 */
+	if (raid->rowDataSize == 0) {
+		if (MR_LdSpanPtrGet(ld, 0, map)->spanRowDataSize == 0)
+			return false;
+		else if (instance->UnevenSpanSupport) {
+			io_info->IoforUnevenSpan = 1;
+		} else {
+			dev_info(&instance->pdev->dev,
+				"raid->rowDataSize is 0, but has SPAN[0]"
+				"rowDataSize = 0x%0x,"
+				"but there is _NO_ UnevenSpanSupport\n",
+				MR_LdSpanPtrGet(ld, 0, map)->spanRowDataSize);
+			return false;
+		}
+	}
+
+	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 (io_info->IoforUnevenSpan) {
+		start_row = get_row_from_strip(instance, ld, start_strip, map);
+		endRow	  = get_row_from_strip(instance, ld, endStrip, map);
+		if (start_row == -1ULL || endRow == -1ULL) {
+			dev_info(&instance->pdev->dev, "return from %s %d."
+				"Send IO w/o region lock.\n",
+				__func__, __LINE__);
+			return false;
+		}
+
+		if (raid->spanDepth == 1) {
+			startlba_span = 0;
+			*pdBlock = start_row << raid->stripeShift;
+		} else
+			startlba_span = (u8)mr_spanset_get_span_block(instance,
+						ld, start_row, pdBlock, map);
+		if (startlba_span == SPAN_INVALID) {
+			dev_info(&instance->pdev->dev, "return from %s %d"
+				"for row 0x%llx,start strip %llx"
+				"endSrip %llx\n", __func__, __LINE__,
+				(unsigned long long)start_row,
+				(unsigned long long)start_strip,
+				(unsigned long long)endStrip);
+			return false;
+		}
+		io_info->start_span	= startlba_span;
+		io_info->start_row	= start_row;
+	} else {
+		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;
+
+	io_info->do_fp_rlbypass = raid->capability.fpBypassRegionLock;
+
+	/* 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 (io_info->IoforUnevenSpan == 0) {
+		/*
+		 * For Even span region lock optimization.
+		 * If the start strip is the last in the start row
+		 */
+		if (start_strip == (start_row + 1) * raid->rowDataSize - 1) {
+			regStart += ref_in_start_stripe;
+			/* initialize count to sectors from startref to end
+			   of strip */
+			regSize = stripSize - ref_in_start_stripe;
+		}
+
+		/* add complete rows in the middle of the transfer */
+		if (numRows > 2)
+			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;
+	} else {
+		/*
+		 * For Uneven span region lock optimization.
+		 * If the start strip is the last in the start row
+		 */
+		if (start_strip == (get_strip_from_row(instance, ld, start_row, map) +
+				SPAN_ROW_DATA_SIZE(map, ld, startlba_span) - 1)) {
+			regStart += ref_in_start_stripe;
+			/* initialize count to sectors from
+			 * startRef to end of strip
+			 */
+			regSize = stripSize - ref_in_start_stripe;
+		}
+		/* Add complete rows in the middle of the transfer*/
+
+		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 == get_strip_from_row(instance, ld, endRow, map))
+			regSize += ref_in_end_stripe + 1;
+		else
+			regSize += stripSize;
+	}
+
+	pRAID_Context->timeout_value =
+		cpu_to_le16(raid->fpIoTimeoutForLd ?
+			    raid->fpIoTimeoutForLd :
+			    map->raidMap.fpPdIoTimeoutSec);
+	if (instance->adapter_type == INVADER_SERIES)
+		pRAID_Context->reg_lock_flags = (isRead) ?
+			raid->regTypeReqOnRead : raid->regTypeReqOnWrite;
+	else if (instance->adapter_type == THUNDERBOLT_SERIES)
+		pRAID_Context->reg_lock_flags = (isRead) ?
+			REGION_TYPE_SHARED_READ : raid->regTypeReqOnWrite;
+	pRAID_Context->virtual_disk_tgt_id = raid->targetId;
+	pRAID_Context->reg_lock_row_lba    = cpu_to_le64(regStart);
+	pRAID_Context->reg_lock_length    = cpu_to_le32(regSize);
+	pRAID_Context->config_seq_num	= raid->seqNum;
+	/* save pointer to raid->LUN array */
+	*raidLUN = raid->LUN;
+
+
+	/*Get Phy Params only if FP capable, or else leave it to MR firmware
+	  to do the calculation.*/
+	if (io_info->fpOkForIo) {
+		retval = io_info->IoforUnevenSpan ?
+				mr_spanset_get_phy_params(instance, ld,
+					start_strip, ref_in_start_stripe,
+					io_info, pRAID_Context, map) :
+				MR_GetPhyParams(instance, ld, start_strip,
+					ref_in_start_stripe, io_info,
+					pRAID_Context, map);
+		/* If IO on an invalid Pd, then FP is not possible.*/
+		if (io_info->devHandle == MR_DEVHANDLE_INVALID)
+			io_info->fpOkForIo = false;
+		return retval;
+	} else if (isRead) {
+		uint stripIdx;
+		for (stripIdx = 0; stripIdx < num_strips; stripIdx++) {
+			retval = io_info->IoforUnevenSpan ?
+				mr_spanset_get_phy_params(instance, ld,
+				    start_strip + stripIdx,
+				    ref_in_start_stripe, io_info,
+				    pRAID_Context, map) :
+				MR_GetPhyParams(instance, ld,
+				    start_strip + stripIdx, ref_in_start_stripe,
+				    io_info, pRAID_Context, map);
+			if (!retval)
+				return true;
+		}
+	}
+	return true;
+}
+
+/*
+******************************************************************************
+*
+* This routine pepare spanset info from Valid Raid map and store it into
+* local copy of ldSpanInfo per instance data structure.
+*
+* Inputs :
+* map    - LD map
+* ldSpanInfo - ldSpanInfo per HBA instance
+*
+*/
+void mr_update_span_set(struct MR_DRV_RAID_MAP_ALL *map,
+	PLD_SPAN_INFO ldSpanInfo)
+{
+	u8   span, count;
+	u32  element, span_row_width;
+	u64  span_row;
+	struct MR_LD_RAID *raid;
+	LD_SPAN_SET *span_set, *span_set_prev;
+	struct MR_QUAD_ELEMENT    *quad;
+	int ldCount;
+	u16 ld;
+
+
+	for (ldCount = 0; ldCount < MAX_LOGICAL_DRIVES_EXT; ldCount++) {
+		ld = MR_TargetIdToLdGet(ldCount, map);
+		if (ld >= (MAX_LOGICAL_DRIVES_EXT - 1))
+			continue;
+		raid = MR_LdRaidGet(ld, map);
+		for (element = 0; element < MAX_QUAD_DEPTH; element++) {
+			for (span = 0; span < raid->spanDepth; span++) {
+				if (le32_to_cpu(map->raidMap.ldSpanMap[ld].spanBlock[span].
+					block_span_info.noElements) <
+					element + 1)
+					continue;
+				span_set = &(ldSpanInfo[ld].span_set[element]);
+				quad = &map->raidMap.ldSpanMap[ld].
+					spanBlock[span].block_span_info.
+					quad[element];
+
+				span_set->diff = le32_to_cpu(quad->diff);
+
+				for (count = 0, span_row_width = 0;
+					count < raid->spanDepth; count++) {
+					if (le32_to_cpu(map->raidMap.ldSpanMap[ld].
+						spanBlock[count].
+						block_span_info.
+						noElements) >= element + 1) {
+						span_set->strip_offset[count] =
+							span_row_width;
+						span_row_width +=
+							MR_LdSpanPtrGet
+							(ld, count, map)->spanRowDataSize;
+					}
+				}
+
+				span_set->span_row_data_width = span_row_width;
+				span_row = mega_div64_32(((le64_to_cpu(quad->logEnd) -
+					le64_to_cpu(quad->logStart)) + le32_to_cpu(quad->diff)),
+					le32_to_cpu(quad->diff));
+
+				if (element == 0) {
+					span_set->log_start_lba = 0;
+					span_set->log_end_lba =
+						((span_row << raid->stripeShift)
+						* span_row_width) - 1;
+
+					span_set->span_row_start = 0;
+					span_set->span_row_end = span_row - 1;
+
+					span_set->data_strip_start = 0;
+					span_set->data_strip_end =
+						(span_row * span_row_width) - 1;
+
+					span_set->data_row_start = 0;
+					span_set->data_row_end =
+						(span_row * le32_to_cpu(quad->diff)) - 1;
+				} else {
+					span_set_prev = &(ldSpanInfo[ld].
+							span_set[element - 1]);
+					span_set->log_start_lba =
+						span_set_prev->log_end_lba + 1;
+					span_set->log_end_lba =
+						span_set->log_start_lba +
+						((span_row << raid->stripeShift)
+						* span_row_width) - 1;
+
+					span_set->span_row_start =
+						span_set_prev->span_row_end + 1;
+					span_set->span_row_end =
+					span_set->span_row_start + span_row - 1;
+
+					span_set->data_strip_start =
+					span_set_prev->data_strip_end + 1;
+					span_set->data_strip_end =
+						span_set->data_strip_start +
+						(span_row * span_row_width) - 1;
+
+					span_set->data_row_start =
+						span_set_prev->data_row_end + 1;
+					span_set->data_row_end =
+						span_set->data_row_start +
+						(span_row * le32_to_cpu(quad->diff)) - 1;
+				}
+				break;
+		}
+		if (span == raid->spanDepth)
+			break;
+	    }
+	}
+}
+
+void mr_update_load_balance_params(struct MR_DRV_RAID_MAP_ALL *drv_map,
+	struct LD_LOAD_BALANCE_INFO *lbInfo)
+{
+	int ldCount;
+	u16 ld;
+	struct MR_LD_RAID *raid;
+
+	if (lb_pending_cmds > 128 || lb_pending_cmds < 1)
+		lb_pending_cmds = LB_PENDING_CMDS_DEFAULT;
+
+	for (ldCount = 0; ldCount < MAX_LOGICAL_DRIVES_EXT; ldCount++) {
+		ld = MR_TargetIdToLdGet(ldCount, drv_map);
+		if (ld >= MAX_LOGICAL_DRIVES_EXT - 1) {
+			lbInfo[ldCount].loadBalanceFlag = 0;
+			continue;
+		}
+
+		raid = MR_LdRaidGet(ld, drv_map);
+		if ((raid->level != 1) ||
+			(raid->ldState != MR_LD_STATE_OPTIMAL)) {
+			lbInfo[ldCount].loadBalanceFlag = 0;
+			continue;
+		}
+		lbInfo[ldCount].loadBalanceFlag = 1;
+	}
+}
+
+u8 megasas_get_best_arm_pd(struct megasas_instance *instance,
+			   struct LD_LOAD_BALANCE_INFO *lbInfo,
+			   struct IO_REQUEST_INFO *io_info,
+			   struct MR_DRV_RAID_MAP_ALL *drv_map)
+{
+	struct MR_LD_RAID  *raid;
+	u16	pd1_dev_handle;
+	u16     pend0, pend1, ld;
+	u64     diff0, diff1;
+	u8      bestArm, pd0, pd1, span, arm;
+	u32     arRef, span_row_size;
+
+	u64 block = io_info->ldStartBlock;
+	u32 count = io_info->numBlocks;
+
+	span = ((io_info->span_arm & RAID_CTX_SPANARM_SPAN_MASK)
+			>> RAID_CTX_SPANARM_SPAN_SHIFT);
+	arm = (io_info->span_arm & RAID_CTX_SPANARM_ARM_MASK);
+
+	ld = MR_TargetIdToLdGet(io_info->ldTgtId, drv_map);
+	raid = MR_LdRaidGet(ld, drv_map);
+	span_row_size = instance->UnevenSpanSupport ?
+			SPAN_ROW_SIZE(drv_map, ld, span) : raid->rowSize;
+
+	arRef = MR_LdSpanArrayGet(ld, span, drv_map);
+	pd0 = MR_ArPdGet(arRef, arm, drv_map);
+	pd1 = MR_ArPdGet(arRef, (arm + 1) >= span_row_size ?
+		(arm + 1 - span_row_size) : arm + 1, drv_map);
+
+	/* Get PD1 Dev Handle */
+
+	pd1_dev_handle = MR_PdDevHandleGet(pd1, drv_map);
+
+	if (pd1_dev_handle == MR_DEVHANDLE_INVALID) {
+		bestArm = arm;
+	} else {
+		/* get the pending cmds for the data and mirror arms */
+		pend0 = atomic_read(&lbInfo->scsi_pending_cmds[pd0]);
+		pend1 = atomic_read(&lbInfo->scsi_pending_cmds[pd1]);
+
+		/* Determine the disk whose head is nearer to the req. block */
+		diff0 = ABS_DIFF(block, lbInfo->last_accessed_block[pd0]);
+		diff1 = ABS_DIFF(block, lbInfo->last_accessed_block[pd1]);
+		bestArm = (diff0 <= diff1 ? arm : arm ^ 1);
+
+		/* Make balance count from 16 to 4 to
+		 *  keep driver in sync with Firmware
+		 */
+		if ((bestArm == arm && pend0 > pend1 + lb_pending_cmds)  ||
+		    (bestArm != arm && pend1 > pend0 + lb_pending_cmds))
+			bestArm ^= 1;
+
+		/* Update the last accessed block on the correct pd */
+		io_info->span_arm =
+			(span << RAID_CTX_SPANARM_SPAN_SHIFT) | bestArm;
+		io_info->pd_after_lb = (bestArm == arm) ? pd0 : pd1;
+	}
+
+	lbInfo->last_accessed_block[io_info->pd_after_lb] = block + count - 1;
+	return io_info->pd_after_lb;
+}
+
+__le16 get_updated_dev_handle(struct megasas_instance *instance,
+			      struct LD_LOAD_BALANCE_INFO *lbInfo,
+			      struct IO_REQUEST_INFO *io_info,
+			      struct MR_DRV_RAID_MAP_ALL *drv_map)
+{
+	u8 arm_pd;
+	__le16 devHandle;
+
+	/* get best new arm (PD ID) */
+	arm_pd  = megasas_get_best_arm_pd(instance, lbInfo, io_info, drv_map);
+	devHandle = MR_PdDevHandleGet(arm_pd, drv_map);
+	io_info->pd_interface = MR_PdInterfaceTypeGet(arm_pd, drv_map);
+	atomic_inc(&lbInfo->scsi_pending_cmds[arm_pd]);
+
+	return devHandle;
+}