scsi: megaraid_sas: Offload Aero RAID5/6 division calculations to driver

For RAID5/RAID6 volumes configured behind Aero, driver will be doing 64bit
division operations on behalf of firmware as controller's ARM CPU is very
slow in this division. Later, driver calculates Q-ARM, P-ARM and Log-ARM and
passes those values to firmware by writing these values to RAID_CONTEXT.

Signed-off-by: Sumit Saxena <sumit.saxena@broadcom.com>
Signed-off-by: Chandrakanth Patil <chandrakanth.patil@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 78 insertions, 0 deletions

diff --git a/drivers/scsi/megaraid/megaraid_sas_fp.c b/drivers/scsi/megaraid/megaraid_sas_fp.c
index d296255a4f12..43a2e49807c4 100644
--- a/drivers/scsi/megaraid/megaraid_sas_fp.c
+++ b/drivers/scsi/megaraid/megaraid_sas_fp.c
@@ -902,6 +902,77 @@ u8 MR_GetPhyParams(struct megasas_instance *instance, u32 ld, u64 stripRow,
 }
 
 /*
+ * mr_get_phy_params_r56_rmw -  Calculate parameters for R56 CTIO write operation
+ * @instance:			Adapter soft state
+ * @ld:				LD index
+ * @stripNo:			Strip Number
+ * @io_info:			IO info structure pointer
+ * pRAID_Context:		RAID context pointer
+ * map:				RAID map pointer
+ *
+ * This routine calculates the logical arm, data Arm, row number and parity arm
+ * for R56 CTIO write operation.
+ */
+static void mr_get_phy_params_r56_rmw(struct megasas_instance *instance,
+			    u32 ld, u64 stripNo,
+			    struct IO_REQUEST_INFO *io_info,
+			    struct RAID_CONTEXT_G35 *pRAID_Context,
+			    struct MR_DRV_RAID_MAP_ALL *map)
+{
+	struct MR_LD_RAID  *raid = MR_LdRaidGet(ld, map);
+	u8          span, dataArms, arms, dataArm, logArm;
+	s8          rightmostParityArm, PParityArm;
+	u64         rowNum;
+	u64 *pdBlock = &io_info->pdBlock;
+
+	dataArms = raid->rowDataSize;
+	arms = raid->rowSize;
+
+	rowNum =  mega_div64_32(stripNo, dataArms);
+	/* parity disk arm, first arm is 0 */
+	rightmostParityArm = (arms - 1) - mega_mod64(rowNum, arms);
+
+	/* logical arm within row */
+	logArm =  mega_mod64(stripNo, dataArms);
+	/* physical arm for data */
+	dataArm = mega_mod64((rightmostParityArm + 1 + logArm), arms);
+
+	if (raid->spanDepth == 1) {
+		span = 0;
+	} else {
+		span = (u8)MR_GetSpanBlock(ld, rowNum, pdBlock, map);
+		if (span == SPAN_INVALID)
+			return;
+	}
+
+	if (raid->level == 6) {
+		/* P Parity arm, note this can go negative adjust if negative */
+		PParityArm = (arms - 2) - mega_mod64(rowNum, arms);
+
+		if (PParityArm < 0)
+			PParityArm += arms;
+
+		/* rightmostParityArm is P-Parity for RAID 5 and Q-Parity for RAID */
+		pRAID_Context->flow_specific.r56_arm_map = rightmostParityArm;
+		pRAID_Context->flow_specific.r56_arm_map |=
+				    (u16)(PParityArm << RAID_CTX_R56_P_ARM_SHIFT);
+	} else {
+		pRAID_Context->flow_specific.r56_arm_map |=
+				    (u16)(rightmostParityArm << RAID_CTX_R56_P_ARM_SHIFT);
+	}
+
+	pRAID_Context->reg_lock_row_lba = cpu_to_le64(rowNum);
+	pRAID_Context->flow_specific.r56_arm_map |=
+				   (u16)(logArm << RAID_CTX_R56_LOG_ARM_SHIFT);
+	cpu_to_le16s(&pRAID_Context->flow_specific.r56_arm_map);
+	pRAID_Context->span_arm = (span << RAID_CTX_SPANARM_SPAN_SHIFT) | dataArm;
+	pRAID_Context->raid_flags = (MR_RAID_FLAGS_IO_SUB_TYPE_R56_DIV_OFFLOAD <<
+				    MR_RAID_CTX_RAID_FLAGS_IO_SUB_TYPE_SHIFT);
+
+	return;
+}
+
+/*
 ******************************************************************************
 *
 * MR_BuildRaidContext function
@@ -1108,6 +1179,13 @@ MR_BuildRaidContext(struct megasas_instance *instance,
 	/* save pointer to raid->LUN array */
 	*raidLUN = raid->LUN;
 
+	/* Aero R5/6 Division Offload for WRITE */
+	if (fusion->r56_div_offload && (raid->level >= 5) && !isRead) {
+		mr_get_phy_params_r56_rmw(instance, ld, start_strip, io_info,
+				       (struct RAID_CONTEXT_G35 *)pRAID_Context,
+				       map);
+		return true;
+	}
 
 	/*Get Phy Params only if FP capable, or else leave it to MR firmware
 	  to do the calculation.*/