[karo-tx-linux.git] / drivers / scsi / ufs / ufshcd.c

/*
 * Universal Flash Storage Host controller driver Core
 *
 * This code is based on drivers/scsi/ufs/ufshcd.c
 * Copyright (C) 2011-2013 Samsung India Software Operations
 *
 * Authors:
 *      Santosh Yaraganavi <santosh.sy@samsung.com>
 *      Vinayak Holikatti <h.vinayak@samsung.com>
 *
 * 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.
 * See the COPYING file in the top-level directory or visit
 * <http://www.gnu.org/licenses/gpl-2.0.html>
 *
 * 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.
 *
 * This program is provided "AS IS" and "WITH ALL FAULTS" and
 * without warranty of any kind. You are solely responsible for
 * determining the appropriateness of using and distributing
 * the program and assume all risks associated with your exercise
 * of rights with respect to the program, including but not limited
 * to infringement of third party rights, the risks and costs of
 * program errors, damage to or loss of data, programs or equipment,
 * and unavailability or interruption of operations. Under no
 * circumstances will the contributor of this Program be liable for
 * any damages of any kind arising from your use or distribution of
 * this program.
 */

#include <linux/async.h>

#include "ufshcd.h"

#define UFSHCD_ENABLE_INTRS     (UTP_TRANSFER_REQ_COMPL |\
                                 UTP_TASK_REQ_COMPL |\
                                 UFSHCD_ERROR_MASK)
/* UIC command timeout, unit: ms */
#define UIC_CMD_TIMEOUT 500

/* NOP OUT retries waiting for NOP IN response */
#define NOP_OUT_RETRIES    10
/* Timeout after 30 msecs if NOP OUT hangs without response */
#define NOP_OUT_TIMEOUT    30 /* msecs */

enum {
        UFSHCD_MAX_CHANNEL      = 0,
        UFSHCD_MAX_ID           = 1,
        UFSHCD_MAX_LUNS         = 8,
        UFSHCD_CMD_PER_LUN      = 32,
        UFSHCD_CAN_QUEUE        = 32,
};

/* UFSHCD states */
enum {
        UFSHCD_STATE_OPERATIONAL,
        UFSHCD_STATE_RESET,
        UFSHCD_STATE_ERROR,
};

/* Interrupt configuration options */
enum {
        UFSHCD_INT_DISABLE,
        UFSHCD_INT_ENABLE,
        UFSHCD_INT_CLEAR,
};

/* Interrupt aggregation options */
enum {
        INT_AGGR_RESET,
        INT_AGGR_CONFIG,
};

/*
 * ufshcd_wait_for_register - wait for register value to change
 * @hba - per-adapter interface
 * @reg - mmio register offset
 * @mask - mask to apply to read register value
 * @val - wait condition
 * @interval_us - polling interval in microsecs
 * @timeout_ms - timeout in millisecs
 *
 * Returns -ETIMEDOUT on error, zero on success
 */
static int ufshcd_wait_for_register(struct ufs_hba *hba, u32 reg, u32 mask,
                u32 val, unsigned long interval_us, unsigned long timeout_ms)
{
        int err = 0;
        unsigned long timeout = jiffies + msecs_to_jiffies(timeout_ms);

        /* ignore bits that we don't intend to wait on */
        val = val & mask;

        while ((ufshcd_readl(hba, reg) & mask) != val) {
                /* wakeup within 50us of expiry */
                usleep_range(interval_us, interval_us + 50);

                if (time_after(jiffies, timeout)) {
                        if ((ufshcd_readl(hba, reg) & mask) != val)
                                err = -ETIMEDOUT;
                        break;
                }
        }

        return err;
}

/**
 * ufshcd_get_intr_mask - Get the interrupt bit mask
 * @hba - Pointer to adapter instance
 *
 * Returns interrupt bit mask per version
 */
static inline u32 ufshcd_get_intr_mask(struct ufs_hba *hba)
{
        if (hba->ufs_version == UFSHCI_VERSION_10)
                return INTERRUPT_MASK_ALL_VER_10;
        else
                return INTERRUPT_MASK_ALL_VER_11;
}

/**
 * ufshcd_get_ufs_version - Get the UFS version supported by the HBA
 * @hba - Pointer to adapter instance
 *
 * Returns UFSHCI version supported by the controller
 */
static inline u32 ufshcd_get_ufs_version(struct ufs_hba *hba)
{
        return ufshcd_readl(hba, REG_UFS_VERSION);
}

/**
 * ufshcd_is_device_present - Check if any device connected to
 *                            the host controller
 * @reg_hcs - host controller status register value
 *
 * Returns 1 if device present, 0 if no device detected
 */
static inline int ufshcd_is_device_present(u32 reg_hcs)
{
        return (DEVICE_PRESENT & reg_hcs) ? 1 : 0;
}

/**
 * ufshcd_get_tr_ocs - Get the UTRD Overall Command Status
 * @lrb: pointer to local command reference block
 *
 * This function is used to get the OCS field from UTRD
 * Returns the OCS field in the UTRD
 */
static inline int ufshcd_get_tr_ocs(struct ufshcd_lrb *lrbp)
{
        return lrbp->utr_descriptor_ptr->header.dword_2 & MASK_OCS;
}

/**
 * ufshcd_get_tmr_ocs - Get the UTMRD Overall Command Status
 * @task_req_descp: pointer to utp_task_req_desc structure
 *
 * This function is used to get the OCS field from UTMRD
 * Returns the OCS field in the UTMRD
 */
static inline int
ufshcd_get_tmr_ocs(struct utp_task_req_desc *task_req_descp)
{
        return task_req_descp->header.dword_2 & MASK_OCS;
}

/**
 * ufshcd_get_tm_free_slot - get a free slot for task management request
 * @hba: per adapter instance
 *
 * Returns maximum number of task management request slots in case of
 * task management queue full or returns the free slot number
 */
static inline int ufshcd_get_tm_free_slot(struct ufs_hba *hba)
{
        return find_first_zero_bit(&hba->outstanding_tasks, hba->nutmrs);
}

/**
 * ufshcd_utrl_clear - Clear a bit in UTRLCLR register
 * @hba: per adapter instance
 * @pos: position of the bit to be cleared
 */
static inline void ufshcd_utrl_clear(struct ufs_hba *hba, u32 pos)
{
        ufshcd_writel(hba, ~(1 << pos), REG_UTP_TRANSFER_REQ_LIST_CLEAR);
}

/**
 * ufshcd_get_lists_status - Check UCRDY, UTRLRDY and UTMRLRDY
 * @reg: Register value of host controller status
 *
 * Returns integer, 0 on Success and positive value if failed
 */
static inline int ufshcd_get_lists_status(u32 reg)
{
        /*
         * The mask 0xFF is for the following HCS register bits
         * Bit          Description
         *  0           Device Present
         *  1           UTRLRDY
         *  2           UTMRLRDY
         *  3           UCRDY
         *  4           HEI
         *  5           DEI
         * 6-7          reserved
         */
        return (((reg) & (0xFF)) >> 1) ^ (0x07);
}

/**
 * ufshcd_get_uic_cmd_result - Get the UIC command result
 * @hba: Pointer to adapter instance
 *
 * This function gets the result of UIC command completion
 * Returns 0 on success, non zero value on error
 */
static inline int ufshcd_get_uic_cmd_result(struct ufs_hba *hba)
{
        return ufshcd_readl(hba, REG_UIC_COMMAND_ARG_2) &
               MASK_UIC_COMMAND_RESULT;
}

/**
 * ufshcd_get_req_rsp - returns the TR response transaction type
 * @ucd_rsp_ptr: pointer to response UPIU
 */
static inline int
ufshcd_get_req_rsp(struct utp_upiu_rsp *ucd_rsp_ptr)
{
        return be32_to_cpu(ucd_rsp_ptr->header.dword_0) >> 24;
}

/**
 * ufshcd_get_rsp_upiu_result - Get the result from response UPIU
 * @ucd_rsp_ptr: pointer to response UPIU
 *
 * This function gets the response status and scsi_status from response UPIU
 * Returns the response result code.
 */
static inline int
ufshcd_get_rsp_upiu_result(struct utp_upiu_rsp *ucd_rsp_ptr)
{
        return be32_to_cpu(ucd_rsp_ptr->header.dword_1) & MASK_RSP_UPIU_RESULT;
}

/**
 * ufshcd_config_int_aggr - Configure interrupt aggregation values.
 *              Currently there is no use case where we want to configure
 *              interrupt aggregation dynamically. So to configure interrupt
 *              aggregation, #define INT_AGGR_COUNTER_THRESHOLD_VALUE and
 *              INT_AGGR_TIMEOUT_VALUE are used.
 * @hba: per adapter instance
 * @option: Interrupt aggregation option
 */
static inline void
ufshcd_config_int_aggr(struct ufs_hba *hba, int option)
{
        switch (option) {
        case INT_AGGR_RESET:
                ufshcd_writel(hba, INT_AGGR_ENABLE |
                              INT_AGGR_COUNTER_AND_TIMER_RESET,
                              REG_UTP_TRANSFER_REQ_INT_AGG_CONTROL);
                break;
        case INT_AGGR_CONFIG:
                ufshcd_writel(hba, INT_AGGR_ENABLE | INT_AGGR_PARAM_WRITE |
                              INT_AGGR_COUNTER_THRESHOLD_VALUE |
                              INT_AGGR_TIMEOUT_VALUE,
                              REG_UTP_TRANSFER_REQ_INT_AGG_CONTROL);
                break;
        }
}

/**
 * ufshcd_enable_run_stop_reg - Enable run-stop registers,
 *                      When run-stop registers are set to 1, it indicates the
 *                      host controller that it can process the requests
 * @hba: per adapter instance
 */
static void ufshcd_enable_run_stop_reg(struct ufs_hba *hba)
{
        ufshcd_writel(hba, UTP_TASK_REQ_LIST_RUN_STOP_BIT,
                      REG_UTP_TASK_REQ_LIST_RUN_STOP);
        ufshcd_writel(hba, UTP_TRANSFER_REQ_LIST_RUN_STOP_BIT,
                      REG_UTP_TRANSFER_REQ_LIST_RUN_STOP);
}

/**
 * ufshcd_hba_start - Start controller initialization sequence
 * @hba: per adapter instance
 */
static inline void ufshcd_hba_start(struct ufs_hba *hba)
{
        ufshcd_writel(hba, CONTROLLER_ENABLE, REG_CONTROLLER_ENABLE);
}

/**
 * ufshcd_is_hba_active - Get controller state
 * @hba: per adapter instance
 *
 * Returns zero if controller is active, 1 otherwise
 */
static inline int ufshcd_is_hba_active(struct ufs_hba *hba)
{
        return (ufshcd_readl(hba, REG_CONTROLLER_ENABLE) & 0x1) ? 0 : 1;
}

/**
 * ufshcd_send_command - Send SCSI or device management commands
 * @hba: per adapter instance
 * @task_tag: Task tag of the command
 */
static inline
void ufshcd_send_command(struct ufs_hba *hba, unsigned int task_tag)
{
        __set_bit(task_tag, &hba->outstanding_reqs);
        ufshcd_writel(hba, 1 << task_tag, REG_UTP_TRANSFER_REQ_DOOR_BELL);
}

/**
 * ufshcd_copy_sense_data - Copy sense data in case of check condition
 * @lrb - pointer to local reference block
 */
static inline void ufshcd_copy_sense_data(struct ufshcd_lrb *lrbp)
{
        int len;
        if (lrbp->sense_buffer) {
                len = be16_to_cpu(lrbp->ucd_rsp_ptr->sr.sense_data_len);
                memcpy(lrbp->sense_buffer,
                        lrbp->ucd_rsp_ptr->sr.sense_data,
                        min_t(int, len, SCSI_SENSE_BUFFERSIZE));
        }
}

/**
 * ufshcd_hba_capabilities - Read controller capabilities
 * @hba: per adapter instance
 */
static inline void ufshcd_hba_capabilities(struct ufs_hba *hba)
{
        hba->capabilities = ufshcd_readl(hba, REG_CONTROLLER_CAPABILITIES);

        /* nutrs and nutmrs are 0 based values */
        hba->nutrs = (hba->capabilities & MASK_TRANSFER_REQUESTS_SLOTS) + 1;
        hba->nutmrs =
        ((hba->capabilities & MASK_TASK_MANAGEMENT_REQUEST_SLOTS) >> 16) + 1;
}

/**
 * ufshcd_ready_for_uic_cmd - Check if controller is ready
 *                            to accept UIC commands
 * @hba: per adapter instance
 * Return true on success, else false
 */
static inline bool ufshcd_ready_for_uic_cmd(struct ufs_hba *hba)
{
        if (ufshcd_readl(hba, REG_CONTROLLER_STATUS) & UIC_COMMAND_READY)
                return true;
        else
                return false;
}

/**
 * ufshcd_dispatch_uic_cmd - Dispatch UIC commands to unipro layers
 * @hba: per adapter instance
 * @uic_cmd: UIC command
 *
 * Mutex must be held.
 */
static inline void
ufshcd_dispatch_uic_cmd(struct ufs_hba *hba, struct uic_command *uic_cmd)
{
        WARN_ON(hba->active_uic_cmd);

        hba->active_uic_cmd = uic_cmd;

        /* Write Args */
        ufshcd_writel(hba, uic_cmd->argument1, REG_UIC_COMMAND_ARG_1);
        ufshcd_writel(hba, uic_cmd->argument2, REG_UIC_COMMAND_ARG_2);
        ufshcd_writel(hba, uic_cmd->argument3, REG_UIC_COMMAND_ARG_3);

        /* Write UIC Cmd */
        ufshcd_writel(hba, uic_cmd->command & COMMAND_OPCODE_MASK,
                      REG_UIC_COMMAND);
}

/**
 * ufshcd_wait_for_uic_cmd - Wait complectioin of UIC command
 * @hba: per adapter instance
 * @uic_command: UIC command
 *
 * Must be called with mutex held.
 * Returns 0 only if success.
 */
static int
ufshcd_wait_for_uic_cmd(struct ufs_hba *hba, struct uic_command *uic_cmd)
{
        int ret;
        unsigned long flags;

        if (wait_for_completion_timeout(&uic_cmd->done,
                                        msecs_to_jiffies(UIC_CMD_TIMEOUT)))
                ret = uic_cmd->argument2 & MASK_UIC_COMMAND_RESULT;
        else
                ret = -ETIMEDOUT;

        spin_lock_irqsave(hba->host->host_lock, flags);
        hba->active_uic_cmd = NULL;
        spin_unlock_irqrestore(hba->host->host_lock, flags);

        return ret;
}

/**
 * __ufshcd_send_uic_cmd - Send UIC commands and retrieve the result
 * @hba: per adapter instance
 * @uic_cmd: UIC command
 *
 * Identical to ufshcd_send_uic_cmd() expect mutex. Must be called
 * with mutex held.
 * Returns 0 only if success.
 */
static int
__ufshcd_send_uic_cmd(struct ufs_hba *hba, struct uic_command *uic_cmd)
{
        int ret;
        unsigned long flags;

        if (!ufshcd_ready_for_uic_cmd(hba)) {
                dev_err(hba->dev,
                        "Controller not ready to accept UIC commands\n");
                return -EIO;
        }

        init_completion(&uic_cmd->done);

        spin_lock_irqsave(hba->host->host_lock, flags);
        ufshcd_dispatch_uic_cmd(hba, uic_cmd);
        spin_unlock_irqrestore(hba->host->host_lock, flags);

        ret = ufshcd_wait_for_uic_cmd(hba, uic_cmd);

        return ret;
}

/**
 * ufshcd_send_uic_cmd - Send UIC commands and retrieve the result
 * @hba: per adapter instance
 * @uic_cmd: UIC command
 *
 * Returns 0 only if success.
 */
static int
ufshcd_send_uic_cmd(struct ufs_hba *hba, struct uic_command *uic_cmd)
{
        int ret;

        mutex_lock(&hba->uic_cmd_mutex);
        ret = __ufshcd_send_uic_cmd(hba, uic_cmd);
        mutex_unlock(&hba->uic_cmd_mutex);

        return ret;
}

/**
 * ufshcd_map_sg - Map scatter-gather list to prdt
 * @lrbp - pointer to local reference block
 *
 * Returns 0 in case of success, non-zero value in case of failure
 */
static int ufshcd_map_sg(struct ufshcd_lrb *lrbp)
{
        struct ufshcd_sg_entry *prd_table;
        struct scatterlist *sg;
        struct scsi_cmnd *cmd;
        int sg_segments;
        int i;

        cmd = lrbp->cmd;
        sg_segments = scsi_dma_map(cmd);
        if (sg_segments < 0)
                return sg_segments;

        if (sg_segments) {
                lrbp->utr_descriptor_ptr->prd_table_length =
                                        cpu_to_le16((u16) (sg_segments));

                prd_table = (struct ufshcd_sg_entry *)lrbp->ucd_prdt_ptr;

                scsi_for_each_sg(cmd, sg, sg_segments, i) {
                        prd_table[i].size  =
                                cpu_to_le32(((u32) sg_dma_len(sg))-1);
                        prd_table[i].base_addr =
                                cpu_to_le32(lower_32_bits(sg->dma_address));
                        prd_table[i].upper_addr =
                                cpu_to_le32(upper_32_bits(sg->dma_address));
                }
        } else {
                lrbp->utr_descriptor_ptr->prd_table_length = 0;
        }

        return 0;
}

/**
 * ufshcd_enable_intr - enable interrupts
 * @hba: per adapter instance
 * @intrs: interrupt bits
 */
static void ufshcd_enable_intr(struct ufs_hba *hba, u32 intrs)
{
        u32 set = ufshcd_readl(hba, REG_INTERRUPT_ENABLE);

        if (hba->ufs_version == UFSHCI_VERSION_10) {
                u32 rw;
                rw = set & INTERRUPT_MASK_RW_VER_10;
                set = rw | ((set ^ intrs) & intrs);
        } else {
                set |= intrs;
        }

        ufshcd_writel(hba, set, REG_INTERRUPT_ENABLE);
}

/**
 * ufshcd_disable_intr - disable interrupts
 * @hba: per adapter instance
 * @intrs: interrupt bits
 */
static void ufshcd_disable_intr(struct ufs_hba *hba, u32 intrs)
{
        u32 set = ufshcd_readl(hba, REG_INTERRUPT_ENABLE);

        if (hba->ufs_version == UFSHCI_VERSION_10) {
                u32 rw;
                rw = (set & INTERRUPT_MASK_RW_VER_10) &
                        ~(intrs & INTERRUPT_MASK_RW_VER_10);
                set = rw | ((set & intrs) & ~INTERRUPT_MASK_RW_VER_10);

        } else {
                set &= ~intrs;
        }

        ufshcd_writel(hba, set, REG_INTERRUPT_ENABLE);
}

/**
 * ufshcd_prepare_req_desc_hdr() - Fills the requests header
 * descriptor according to request
 * @lrbp: pointer to local reference block
 * @upiu_flags: flags required in the header
 * @cmd_dir: requests data direction
 */
static void ufshcd_prepare_req_desc_hdr(struct ufshcd_lrb *lrbp,
                u32 *upiu_flags, enum dma_data_direction cmd_dir)
{
        struct utp_transfer_req_desc *req_desc = lrbp->utr_descriptor_ptr;
        u32 data_direction;
        u32 dword_0;

        if (cmd_dir == DMA_FROM_DEVICE) {
                data_direction = UTP_DEVICE_TO_HOST;
                *upiu_flags = UPIU_CMD_FLAGS_READ;
        } else if (cmd_dir == DMA_TO_DEVICE) {
                data_direction = UTP_HOST_TO_DEVICE;
                *upiu_flags = UPIU_CMD_FLAGS_WRITE;
        } else {
                data_direction = UTP_NO_DATA_TRANSFER;
                *upiu_flags = UPIU_CMD_FLAGS_NONE;
        }

        dword_0 = data_direction | (lrbp->command_type
                                << UPIU_COMMAND_TYPE_OFFSET);
        if (lrbp->intr_cmd)
                dword_0 |= UTP_REQ_DESC_INT_CMD;

        /* Transfer request descriptor header fields */
        req_desc->header.dword_0 = cpu_to_le32(dword_0);

        /*
         * assigning invalid value for command status. Controller
         * updates OCS on command completion, with the command
         * status
         */
        req_desc->header.dword_2 =
                cpu_to_le32(OCS_INVALID_COMMAND_STATUS);
}

/**
 * ufshcd_prepare_utp_scsi_cmd_upiu() - fills the utp_transfer_req_desc,
 * for scsi commands
 * @lrbp - local reference block pointer
 * @upiu_flags - flags
 */
static
void ufshcd_prepare_utp_scsi_cmd_upiu(struct ufshcd_lrb *lrbp, u32 upiu_flags)
{
        struct utp_upiu_req *ucd_req_ptr = lrbp->ucd_req_ptr;

        /* command descriptor fields */
        ucd_req_ptr->header.dword_0 = UPIU_HEADER_DWORD(
                                UPIU_TRANSACTION_COMMAND, upiu_flags,
                                lrbp->lun, lrbp->task_tag);
        ucd_req_ptr->header.dword_1 = UPIU_HEADER_DWORD(
                                UPIU_COMMAND_SET_TYPE_SCSI, 0, 0, 0);

        /* Total EHS length and Data segment length will be zero */
        ucd_req_ptr->header.dword_2 = 0;

        ucd_req_ptr->sc.exp_data_transfer_len =
                cpu_to_be32(lrbp->cmd->sdb.length);

        memcpy(ucd_req_ptr->sc.cdb, lrbp->cmd->cmnd,
                (min_t(unsigned short, lrbp->cmd->cmd_len, MAX_CDB_SIZE)));
}

static inline void ufshcd_prepare_utp_nop_upiu(struct ufshcd_lrb *lrbp)
{
        struct utp_upiu_req *ucd_req_ptr = lrbp->ucd_req_ptr;

        memset(ucd_req_ptr, 0, sizeof(struct utp_upiu_req));

        /* command descriptor fields */
        ucd_req_ptr->header.dword_0 =
                UPIU_HEADER_DWORD(
                        UPIU_TRANSACTION_NOP_OUT, 0, 0, lrbp->task_tag);
}

/**
 * ufshcd_compose_upiu - form UFS Protocol Information Unit(UPIU)
 * @hba - per adapter instance
 * @lrb - pointer to local reference block
 */
static int ufshcd_compose_upiu(struct ufs_hba *hba, struct ufshcd_lrb *lrbp)
{
        u32 upiu_flags;
        int ret = 0;

        switch (lrbp->command_type) {
        case UTP_CMD_TYPE_SCSI:
                if (likely(lrbp->cmd)) {
                        ufshcd_prepare_req_desc_hdr(lrbp, &upiu_flags,
                                        lrbp->cmd->sc_data_direction);
                        ufshcd_prepare_utp_scsi_cmd_upiu(lrbp, upiu_flags);
                } else {
                        ret = -EINVAL;
                }
                break;
        case UTP_CMD_TYPE_DEV_MANAGE:
                ufshcd_prepare_req_desc_hdr(lrbp, &upiu_flags, DMA_NONE);
                if (hba->dev_cmd.type == DEV_CMD_TYPE_NOP)
                        ufshcd_prepare_utp_nop_upiu(lrbp);
                else
                        ret = -EINVAL;
                break;
        case UTP_CMD_TYPE_UFS:
                /* For UFS native command implementation */
                ret = -ENOTSUPP;
                dev_err(hba->dev, "%s: UFS native command are not supported\n",
                        __func__);
                break;
        default:
                ret = -ENOTSUPP;
                dev_err(hba->dev, "%s: unknown command type: 0x%x\n",
                                __func__, lrbp->command_type);
                break;
        } /* end of switch */

        return ret;
}

/**
 * ufshcd_queuecommand - main entry point for SCSI requests
 * @cmd: command from SCSI Midlayer
 * @done: call back function
 *
 * Returns 0 for success, non-zero in case of failure
 */
static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd)
{
        struct ufshcd_lrb *lrbp;
        struct ufs_hba *hba;
        unsigned long flags;
        int tag;
        int err = 0;

        hba = shost_priv(host);

        tag = cmd->request->tag;

        if (hba->ufshcd_state != UFSHCD_STATE_OPERATIONAL) {
                err = SCSI_MLQUEUE_HOST_BUSY;
                goto out;
        }

        /* acquire the tag to make sure device cmds don't use it */
        if (test_and_set_bit_lock(tag, &hba->lrb_in_use)) {
                /*
                 * Dev manage command in progress, requeue the command.
                 * Requeuing the command helps in cases where the request *may*
                 * find different tag instead of waiting for dev manage command
                 * completion.
                 */
                err = SCSI_MLQUEUE_HOST_BUSY;
                goto out;
        }

        lrbp = &hba->lrb[tag];

        WARN_ON(lrbp->cmd);
        lrbp->cmd = cmd;
        lrbp->sense_bufflen = SCSI_SENSE_BUFFERSIZE;
        lrbp->sense_buffer = cmd->sense_buffer;
        lrbp->task_tag = tag;
        lrbp->lun = cmd->device->lun;
        lrbp->intr_cmd = false;
        lrbp->command_type = UTP_CMD_TYPE_SCSI;

        /* form UPIU before issuing the command */
        ufshcd_compose_upiu(hba, lrbp);
        err = ufshcd_map_sg(lrbp);
        if (err) {
                lrbp->cmd = NULL;
                clear_bit_unlock(tag, &hba->lrb_in_use);
                goto out;
        }

        /* issue command to the controller */
        spin_lock_irqsave(hba->host->host_lock, flags);
        ufshcd_send_command(hba, tag);
        spin_unlock_irqrestore(hba->host->host_lock, flags);
out:
        return err;
}

static int ufshcd_compose_dev_cmd(struct ufs_hba *hba,
                struct ufshcd_lrb *lrbp, enum dev_cmd_type cmd_type, int tag)
{
        lrbp->cmd = NULL;
        lrbp->sense_bufflen = 0;
        lrbp->sense_buffer = NULL;
        lrbp->task_tag = tag;
        lrbp->lun = 0; /* device management cmd is not specific to any LUN */
        lrbp->command_type = UTP_CMD_TYPE_DEV_MANAGE;
        lrbp->intr_cmd = true; /* No interrupt aggregation */
        hba->dev_cmd.type = cmd_type;

        return ufshcd_compose_upiu(hba, lrbp);
}

static int
ufshcd_clear_cmd(struct ufs_hba *hba, int tag)
{
        int err = 0;
        unsigned long flags;
        u32 mask = 1 << tag;

        /* clear outstanding transaction before retry */
        spin_lock_irqsave(hba->host->host_lock, flags);
        ufshcd_utrl_clear(hba, tag);
        spin_unlock_irqrestore(hba->host->host_lock, flags);

        /*
         * wait for for h/w to clear corresponding bit in door-bell.
         * max. wait is 1 sec.
         */
        err = ufshcd_wait_for_register(hba,
                        REG_UTP_TRANSFER_REQ_DOOR_BELL,
                        mask, ~mask, 1000, 1000);

        return err;
}

/**
 * ufshcd_dev_cmd_completion() - handles device management command responses
 * @hba: per adapter instance
 * @lrbp: pointer to local reference block
 */
static int
ufshcd_dev_cmd_completion(struct ufs_hba *hba, struct ufshcd_lrb *lrbp)
{
        int resp;
        int err = 0;

        resp = ufshcd_get_req_rsp(lrbp->ucd_rsp_ptr);

        switch (resp) {
        case UPIU_TRANSACTION_NOP_IN:
                if (hba->dev_cmd.type != DEV_CMD_TYPE_NOP) {
                        err = -EINVAL;
                        dev_err(hba->dev, "%s: unexpected response %x\n",
                                        __func__, resp);
                }
                break;
        case UPIU_TRANSACTION_REJECT_UPIU:
                /* TODO: handle Reject UPIU Response */
                err = -EPERM;
                dev_err(hba->dev, "%s: Reject UPIU not fully implemented\n",
                                __func__);
                break;
        default:
                err = -EINVAL;
                dev_err(hba->dev, "%s: Invalid device management cmd response: %x\n",
                                __func__, resp);
                break;
        }

        return err;
}

static int ufshcd_wait_for_dev_cmd(struct ufs_hba *hba,
                struct ufshcd_lrb *lrbp, int max_timeout)
{
        int err = 0;
        unsigned long time_left;
        unsigned long flags;

        time_left = wait_for_completion_timeout(hba->dev_cmd.complete,
                        msecs_to_jiffies(max_timeout));

        spin_lock_irqsave(hba->host->host_lock, flags);
        hba->dev_cmd.complete = NULL;
        if (likely(time_left)) {
                err = ufshcd_get_tr_ocs(lrbp);
                if (!err)
                        err = ufshcd_dev_cmd_completion(hba, lrbp);
        }
        spin_unlock_irqrestore(hba->host->host_lock, flags);

        if (!time_left) {
                err = -ETIMEDOUT;
                if (!ufshcd_clear_cmd(hba, lrbp->task_tag))
                        /* sucessfully cleared the command, retry if needed */
                        err = -EAGAIN;
        }

        return err;
}

/**
 * ufshcd_get_dev_cmd_tag - Get device management command tag
 * @hba: per-adapter instance
 * @tag: pointer to variable with available slot value
 *
 * Get a free slot and lock it until device management command
 * completes.
 *
 * Returns false if free slot is unavailable for locking, else
 * return true with tag value in @tag.
 */
static bool ufshcd_get_dev_cmd_tag(struct ufs_hba *hba, int *tag_out)
{
        int tag;
        bool ret = false;
        unsigned long tmp;

        if (!tag_out)
                goto out;

        do {
                tmp = ~hba->lrb_in_use;
                tag = find_last_bit(&tmp, hba->nutrs);
                if (tag >= hba->nutrs)
                        goto out;
        } while (test_and_set_bit_lock(tag, &hba->lrb_in_use));

        *tag_out = tag;
        ret = true;
out:
        return ret;
}

static inline void ufshcd_put_dev_cmd_tag(struct ufs_hba *hba, int tag)
{
        clear_bit_unlock(tag, &hba->lrb_in_use);
}

/**
 * ufshcd_exec_dev_cmd - API for sending device management requests
 * @hba - UFS hba
 * @cmd_type - specifies the type (NOP, Query...)
 * @timeout - time in seconds
 *
 * NOTE: There is only one available tag for device management commands. Thus
 * synchronisation is the responsibilty of the user.
 */
static int ufshcd_exec_dev_cmd(struct ufs_hba *hba,
                enum dev_cmd_type cmd_type, int timeout)
{
        struct ufshcd_lrb *lrbp;
        int err;
        int tag;
        struct completion wait;
        unsigned long flags;

        /*
         * Get free slot, sleep if slots are unavailable.
         * Even though we use wait_event() which sleeps indefinitely,
         * the maximum wait time is bounded by SCSI request timeout.
         */
        wait_event(hba->dev_cmd.tag_wq, ufshcd_get_dev_cmd_tag(hba, &tag));

        init_completion(&wait);
        lrbp = &hba->lrb[tag];
        WARN_ON(lrbp->cmd);
        err = ufshcd_compose_dev_cmd(hba, lrbp, cmd_type, tag);
        if (unlikely(err))
                goto out_put_tag;

        hba->dev_cmd.complete = &wait;

        spin_lock_irqsave(hba->host->host_lock, flags);
        ufshcd_send_command(hba, tag);
        spin_unlock_irqrestore(hba->host->host_lock, flags);

        err = ufshcd_wait_for_dev_cmd(hba, lrbp, timeout);

out_put_tag:
        ufshcd_put_dev_cmd_tag(hba, tag);
        wake_up(&hba->dev_cmd.tag_wq);
        return err;
}

/**
 * ufshcd_memory_alloc - allocate memory for host memory space data structures
 * @hba: per adapter instance
 *
 * 1. Allocate DMA memory for Command Descriptor array
 *      Each command descriptor consist of Command UPIU, Response UPIU and PRDT
 * 2. Allocate DMA memory for UTP Transfer Request Descriptor List (UTRDL).
 * 3. Allocate DMA memory for UTP Task Management Request Descriptor List
 *      (UTMRDL)
 * 4. Allocate memory for local reference block(lrb).
 *
 * Returns 0 for success, non-zero in case of failure
 */
static int ufshcd_memory_alloc(struct ufs_hba *hba)
{
        size_t utmrdl_size, utrdl_size, ucdl_size;

        /* Allocate memory for UTP command descriptors */
        ucdl_size = (sizeof(struct utp_transfer_cmd_desc) * hba->nutrs);
        hba->ucdl_base_addr = dmam_alloc_coherent(hba->dev,
                                                  ucdl_size,
                                                  &hba->ucdl_dma_addr,
                                                  GFP_KERNEL);

        /*
         * UFSHCI requires UTP command descriptor to be 128 byte aligned.
         * make sure hba->ucdl_dma_addr is aligned to PAGE_SIZE
         * if hba->ucdl_dma_addr is aligned to PAGE_SIZE, then it will
         * be aligned to 128 bytes as well
         */
        if (!hba->ucdl_base_addr ||
            WARN_ON(hba->ucdl_dma_addr & (PAGE_SIZE - 1))) {
                dev_err(hba->dev,
                        "Command Descriptor Memory allocation failed\n");
                goto out;
        }

        /*
         * Allocate memory for UTP Transfer descriptors
         * UFSHCI requires 1024 byte alignment of UTRD
         */
        utrdl_size = (sizeof(struct utp_transfer_req_desc) * hba->nutrs);
        hba->utrdl_base_addr = dmam_alloc_coherent(hba->dev,
                                                   utrdl_size,
                                                   &hba->utrdl_dma_addr,
                                                   GFP_KERNEL);
        if (!hba->utrdl_base_addr ||
            WARN_ON(hba->utrdl_dma_addr & (PAGE_SIZE - 1))) {
                dev_err(hba->dev,
                        "Transfer Descriptor Memory allocation failed\n");
                goto out;
        }

        /*
         * Allocate memory for UTP Task Management descriptors
         * UFSHCI requires 1024 byte alignment of UTMRD
         */
        utmrdl_size = sizeof(struct utp_task_req_desc) * hba->nutmrs;
        hba->utmrdl_base_addr = dmam_alloc_coherent(hba->dev,
                                                    utmrdl_size,
                                                    &hba->utmrdl_dma_addr,
                                                    GFP_KERNEL);
        if (!hba->utmrdl_base_addr ||
            WARN_ON(hba->utmrdl_dma_addr & (PAGE_SIZE - 1))) {
                dev_err(hba->dev,
                "Task Management Descriptor Memory allocation failed\n");
                goto out;
        }

        /* Allocate memory for local reference block */
        hba->lrb = devm_kzalloc(hba->dev,
                                hba->nutrs * sizeof(struct ufshcd_lrb),
                                GFP_KERNEL);
        if (!hba->lrb) {
                dev_err(hba->dev, "LRB Memory allocation failed\n");
                goto out;
        }
        return 0;
out:
        return -ENOMEM;
}

/**
 * ufshcd_host_memory_configure - configure local reference block with
 *                              memory offsets
 * @hba: per adapter instance
 *
 * Configure Host memory space
 * 1. Update Corresponding UTRD.UCDBA and UTRD.UCDBAU with UCD DMA
 * address.
 * 2. Update each UTRD with Response UPIU offset, Response UPIU length
 * and PRDT offset.
 * 3. Save the corresponding addresses of UTRD, UCD.CMD, UCD.RSP and UCD.PRDT
 * into local reference block.
 */
static void ufshcd_host_memory_configure(struct ufs_hba *hba)
{
        struct utp_transfer_cmd_desc *cmd_descp;
        struct utp_transfer_req_desc *utrdlp;
        dma_addr_t cmd_desc_dma_addr;
        dma_addr_t cmd_desc_element_addr;
        u16 response_offset;
        u16 prdt_offset;
        int cmd_desc_size;
        int i;

        utrdlp = hba->utrdl_base_addr;
        cmd_descp = hba->ucdl_base_addr;

        response_offset =
                offsetof(struct utp_transfer_cmd_desc, response_upiu);
        prdt_offset =
                offsetof(struct utp_transfer_cmd_desc, prd_table);

        cmd_desc_size = sizeof(struct utp_transfer_cmd_desc);
        cmd_desc_dma_addr = hba->ucdl_dma_addr;

        for (i = 0; i < hba->nutrs; i++) {
                /* Configure UTRD with command descriptor base address */
                cmd_desc_element_addr =
                                (cmd_desc_dma_addr + (cmd_desc_size * i));
                utrdlp[i].command_desc_base_addr_lo =
                                cpu_to_le32(lower_32_bits(cmd_desc_element_addr));
                utrdlp[i].command_desc_base_addr_hi =
                                cpu_to_le32(upper_32_bits(cmd_desc_element_addr));

                /* Response upiu and prdt offset should be in double words */
                utrdlp[i].response_upiu_offset =
                                cpu_to_le16((response_offset >> 2));
                utrdlp[i].prd_table_offset =
                                cpu_to_le16((prdt_offset >> 2));
                utrdlp[i].response_upiu_length =
                                cpu_to_le16(ALIGNED_UPIU_SIZE >> 2);

                hba->lrb[i].utr_descriptor_ptr = (utrdlp + i);
                hba->lrb[i].ucd_req_ptr =
                        (struct utp_upiu_req *)(cmd_descp + i);
                hba->lrb[i].ucd_rsp_ptr =
                        (struct utp_upiu_rsp *)cmd_descp[i].response_upiu;
                hba->lrb[i].ucd_prdt_ptr =
                        (struct ufshcd_sg_entry *)cmd_descp[i].prd_table;
        }
}

/**
 * ufshcd_dme_link_startup - Notify Unipro to perform link startup
 * @hba: per adapter instance
 *
 * UIC_CMD_DME_LINK_STARTUP command must be issued to Unipro layer,
 * in order to initialize the Unipro link startup procedure.
 * Once the Unipro links are up, the device connected to the controller
 * is detected.
 *
 * Returns 0 on success, non-zero value on failure
 */
static int ufshcd_dme_link_startup(struct ufs_hba *hba)
{
        struct uic_command uic_cmd = {0};
        int ret;

        uic_cmd.command = UIC_CMD_DME_LINK_STARTUP;

        ret = ufshcd_send_uic_cmd(hba, &uic_cmd);
        if (ret)
                dev_err(hba->dev,
                        "dme-link-startup: error code %d\n", ret);
        return ret;
}

/**
 * ufshcd_make_hba_operational - Make UFS controller operational
 * @hba: per adapter instance
 *
 * To bring UFS host controller to operational state,
 * 1. Check if device is present
 * 2. Enable required interrupts
 * 3. Configure interrupt aggregation
 * 4. Program UTRL and UTMRL base addres
 * 5. Configure run-stop-registers
 *
 * Returns 0 on success, non-zero value on failure
 */
static int ufshcd_make_hba_operational(struct ufs_hba *hba)
{
        int err = 0;
        u32 reg;

        /* check if device present */
        reg = ufshcd_readl(hba, REG_CONTROLLER_STATUS);
        if (!ufshcd_is_device_present(reg)) {
                dev_err(hba->dev, "cc: Device not present\n");
                err = -ENXIO;
                goto out;
        }

        /* Enable required interrupts */
        ufshcd_enable_intr(hba, UFSHCD_ENABLE_INTRS);

        /* Configure interrupt aggregation */
        ufshcd_config_int_aggr(hba, INT_AGGR_CONFIG);

        /* Configure UTRL and UTMRL base address registers */
        ufshcd_writel(hba, lower_32_bits(hba->utrdl_dma_addr),
                        REG_UTP_TRANSFER_REQ_LIST_BASE_L);
        ufshcd_writel(hba, upper_32_bits(hba->utrdl_dma_addr),
                        REG_UTP_TRANSFER_REQ_LIST_BASE_H);
        ufshcd_writel(hba, lower_32_bits(hba->utmrdl_dma_addr),
                        REG_UTP_TASK_REQ_LIST_BASE_L);
        ufshcd_writel(hba, upper_32_bits(hba->utmrdl_dma_addr),
                        REG_UTP_TASK_REQ_LIST_BASE_H);

        /*
         * UCRDY, UTMRLDY and UTRLRDY bits must be 1
         * DEI, HEI bits must be 0
         */
        if (!(ufshcd_get_lists_status(reg))) {
                ufshcd_enable_run_stop_reg(hba);
        } else {
                dev_err(hba->dev,
                        "Host controller not ready to process requests");
                err = -EIO;
                goto out;
        }

        if (hba->ufshcd_state == UFSHCD_STATE_RESET)
                scsi_unblock_requests(hba->host);

        hba->ufshcd_state = UFSHCD_STATE_OPERATIONAL;

out:
        return err;
}

/**
 * ufshcd_hba_enable - initialize the controller
 * @hba: per adapter instance
 *
 * The controller resets itself and controller firmware initialization
 * sequence kicks off. When controller is ready it will set
 * the Host Controller Enable bit to 1.
 *
 * Returns 0 on success, non-zero value on failure
 */
static int ufshcd_hba_enable(struct ufs_hba *hba)
{
        int retry;

        /*
         * msleep of 1 and 5 used in this function might result in msleep(20),
         * but it was necessary to send the UFS FPGA to reset mode during
         * development and testing of this driver. msleep can be changed to
         * mdelay and retry count can be reduced based on the controller.
         */
        if (!ufshcd_is_hba_active(hba)) {

                /* change controller state to "reset state" */
                ufshcd_hba_stop(hba);

                /*
                 * This delay is based on the testing done with UFS host
                 * controller FPGA. The delay can be changed based on the
                 * host controller used.
                 */
                msleep(5);
        }

        /* start controller initialization sequence */
        ufshcd_hba_start(hba);

        /*
         * To initialize a UFS host controller HCE bit must be set to 1.
         * During initialization the HCE bit value changes from 1->0->1.
         * When the host controller completes initialization sequence
         * it sets the value of HCE bit to 1. The same HCE bit is read back
         * to check if the controller has completed initialization sequence.
         * So without this delay the value HCE = 1, set in the previous
         * instruction might be read back.
         * This delay can be changed based on the controller.
         */
        msleep(1);

        /* wait for the host controller to complete initialization */
        retry = 10;
        while (ufshcd_is_hba_active(hba)) {
                if (retry) {
                        retry--;
                } else {
                        dev_err(hba->dev,
                                "Controller enable failed\n");
                        return -EIO;
                }
                msleep(5);
        }
        return 0;
}

/**
 * ufshcd_link_startup - Initialize unipro link startup
 * @hba: per adapter instance
 *
 * Returns 0 for success, non-zero in case of failure
 */
static int ufshcd_link_startup(struct ufs_hba *hba)
{
        int ret;

        /* enable UIC related interrupts */
        ufshcd_enable_intr(hba, UIC_COMMAND_COMPL);

        ret = ufshcd_dme_link_startup(hba);
        if (ret)
                goto out;

        ret = ufshcd_make_hba_operational(hba);

out:
        if (ret)
                dev_err(hba->dev, "link startup failed %d\n", ret);
        return ret;
}

/**
 * ufshcd_verify_dev_init() - Verify device initialization
 * @hba: per-adapter instance
 *
 * Send NOP OUT UPIU and wait for NOP IN response to check whether the
 * device Transport Protocol (UTP) layer is ready after a reset.
 * If the UTP layer at the device side is not initialized, it may
 * not respond with NOP IN UPIU within timeout of %NOP_OUT_TIMEOUT
 * and we retry sending NOP OUT for %NOP_OUT_RETRIES iterations.
 */
static int ufshcd_verify_dev_init(struct ufs_hba *hba)
{
        int err = 0;
        int retries;

        mutex_lock(&hba->dev_cmd.lock);
        for (retries = NOP_OUT_RETRIES; retries > 0; retries--) {
                err = ufshcd_exec_dev_cmd(hba, DEV_CMD_TYPE_NOP,
                                               NOP_OUT_TIMEOUT);

                if (!err || err == -ETIMEDOUT)
                        break;

                dev_dbg(hba->dev, "%s: error %d retrying\n", __func__, err);
        }
        mutex_unlock(&hba->dev_cmd.lock);

        if (err)
                dev_err(hba->dev, "%s: NOP OUT failed %d\n", __func__, err);
        return err;
}

/**
 * ufshcd_do_reset - reset the host controller
 * @hba: per adapter instance
 *
 * Returns SUCCESS/FAILED
 */
static int ufshcd_do_reset(struct ufs_hba *hba)
{
        struct ufshcd_lrb *lrbp;
        unsigned long flags;
        int tag;

        /* block commands from midlayer */
        scsi_block_requests(hba->host);

        spin_lock_irqsave(hba->host->host_lock, flags);
        hba->ufshcd_state = UFSHCD_STATE_RESET;

        /* send controller to reset state */
        ufshcd_hba_stop(hba);
        spin_unlock_irqrestore(hba->host->host_lock, flags);

        /* abort outstanding commands */
        for (tag = 0; tag < hba->nutrs; tag++) {
                if (test_bit(tag, &hba->outstanding_reqs)) {
                        lrbp = &hba->lrb[tag];
                        if (lrbp->cmd) {
                                scsi_dma_unmap(lrbp->cmd);
                                lrbp->cmd->result = DID_RESET << 16;
                                lrbp->cmd->scsi_done(lrbp->cmd);
                                lrbp->cmd = NULL;
                                clear_bit_unlock(tag, &hba->lrb_in_use);
                        }
                }
        }

        /* complete device management command */
        if (hba->dev_cmd.complete)
                complete(hba->dev_cmd.complete);

        /* clear outstanding request/task bit maps */
        hba->outstanding_reqs = 0;
        hba->outstanding_tasks = 0;

        /* Host controller enable */
        if (ufshcd_hba_enable(hba)) {
                dev_err(hba->dev,
                        "Reset: Controller initialization failed\n");
                return FAILED;
        }

        if (ufshcd_link_startup(hba)) {
                dev_err(hba->dev,
                        "Reset: Link start-up failed\n");
                return FAILED;
        }

        return SUCCESS;
}

/**
 * ufshcd_slave_alloc - handle initial SCSI device configurations
 * @sdev: pointer to SCSI device
 *
 * Returns success
 */
static int ufshcd_slave_alloc(struct scsi_device *sdev)
{
        struct ufs_hba *hba;

        hba = shost_priv(sdev->host);
        sdev->tagged_supported = 1;

        /* Mode sense(6) is not supported by UFS, so use Mode sense(10) */
        sdev->use_10_for_ms = 1;
        scsi_set_tag_type(sdev, MSG_SIMPLE_TAG);

        /*
         * Inform SCSI Midlayer that the LUN queue depth is same as the
         * controller queue depth. If a LUN queue depth is less than the
         * controller queue depth and if the LUN reports
         * SAM_STAT_TASK_SET_FULL, the LUN queue depth will be adjusted
         * with scsi_adjust_queue_depth.
         */
        scsi_activate_tcq(sdev, hba->nutrs);
        return 0;
}

/**
 * ufshcd_slave_destroy - remove SCSI device configurations
 * @sdev: pointer to SCSI device
 */
static void ufshcd_slave_destroy(struct scsi_device *sdev)
{
        struct ufs_hba *hba;

        hba = shost_priv(sdev->host);
        scsi_deactivate_tcq(sdev, hba->nutrs);
}

/**
 * ufshcd_task_req_compl - handle task management request completion
 * @hba: per adapter instance
 * @index: index of the completed request
 *
 * Returns SUCCESS/FAILED
 */
static int ufshcd_task_req_compl(struct ufs_hba *hba, u32 index)
{
        struct utp_task_req_desc *task_req_descp;
        struct utp_upiu_task_rsp *task_rsp_upiup;
        unsigned long flags;
        int ocs_value;
        int task_result;

        spin_lock_irqsave(hba->host->host_lock, flags);

        /* Clear completed tasks from outstanding_tasks */
        __clear_bit(index, &hba->outstanding_tasks);

        task_req_descp = hba->utmrdl_base_addr;
        ocs_value = ufshcd_get_tmr_ocs(&task_req_descp[index]);

        if (ocs_value == OCS_SUCCESS) {
                task_rsp_upiup = (struct utp_upiu_task_rsp *)
                                task_req_descp[index].task_rsp_upiu;
                task_result = be32_to_cpu(task_rsp_upiup->header.dword_1);
                task_result = ((task_result & MASK_TASK_RESPONSE) >> 8);

                if (task_result != UPIU_TASK_MANAGEMENT_FUNC_COMPL &&
                    task_result != UPIU_TASK_MANAGEMENT_FUNC_SUCCEEDED)
                        task_result = FAILED;
                else
                        task_result = SUCCESS;
        } else {
                task_result = FAILED;
                dev_err(hba->dev,
                        "trc: Invalid ocs = %x\n", ocs_value);
        }
        spin_unlock_irqrestore(hba->host->host_lock, flags);
        return task_result;
}

/**
 * ufshcd_adjust_lun_qdepth - Update LUN queue depth if device responds with
 *                            SAM_STAT_TASK_SET_FULL SCSI command status.
 * @cmd: pointer to SCSI command
 */
static void ufshcd_adjust_lun_qdepth(struct scsi_cmnd *cmd)
{
        struct ufs_hba *hba;
        int i;
        int lun_qdepth = 0;

        hba = shost_priv(cmd->device->host);

        /*
         * LUN queue depth can be obtained by counting outstanding commands
         * on the LUN.
         */
        for (i = 0; i < hba->nutrs; i++) {
                if (test_bit(i, &hba->outstanding_reqs)) {

                        /*
                         * Check if the outstanding command belongs
                         * to the LUN which reported SAM_STAT_TASK_SET_FULL.
                         */
                        if (cmd->device->lun == hba->lrb[i].lun)
                                lun_qdepth++;
                }
        }

        /*
         * LUN queue depth will be total outstanding commands, except the
         * command for which the LUN reported SAM_STAT_TASK_SET_FULL.
         */
        scsi_adjust_queue_depth(cmd->device, MSG_SIMPLE_TAG, lun_qdepth - 1);
}

/**
 * ufshcd_scsi_cmd_status - Update SCSI command result based on SCSI status
 * @lrb: pointer to local reference block of completed command
 * @scsi_status: SCSI command status
 *
 * Returns value base on SCSI command status
 */
static inline int
ufshcd_scsi_cmd_status(struct ufshcd_lrb *lrbp, int scsi_status)
{
        int result = 0;

        switch (scsi_status) {
        case SAM_STAT_GOOD:
                result |= DID_OK << 16 |
                          COMMAND_COMPLETE << 8 |
                          SAM_STAT_GOOD;
                break;
        case SAM_STAT_CHECK_CONDITION:
                result |= DID_OK << 16 |
                          COMMAND_COMPLETE << 8 |
                          SAM_STAT_CHECK_CONDITION;
                ufshcd_copy_sense_data(lrbp);
                break;
        case SAM_STAT_BUSY:
                result |= SAM_STAT_BUSY;
                break;
        case SAM_STAT_TASK_SET_FULL:

                /*
                 * If a LUN reports SAM_STAT_TASK_SET_FULL, then the LUN queue
                 * depth needs to be adjusted to the exact number of
                 * outstanding commands the LUN can handle at any given time.
                 */
                ufshcd_adjust_lun_qdepth(lrbp->cmd);
                result |= SAM_STAT_TASK_SET_FULL;
                break;
        case SAM_STAT_TASK_ABORTED:
                result |= SAM_STAT_TASK_ABORTED;
                break;
        default:
                result |= DID_ERROR << 16;
                break;
        } /* end of switch */

        return result;
}

/**
 * ufshcd_transfer_rsp_status - Get overall status of the response
 * @hba: per adapter instance
 * @lrb: pointer to local reference block of completed command
 *
 * Returns result of the command to notify SCSI midlayer
 */
static inline int
ufshcd_transfer_rsp_status(struct ufs_hba *hba, struct ufshcd_lrb *lrbp)
{
        int result = 0;
        int scsi_status;
        int ocs;

        /* overall command status of utrd */
        ocs = ufshcd_get_tr_ocs(lrbp);

        switch (ocs) {
        case OCS_SUCCESS:
                result = ufshcd_get_req_rsp(lrbp->ucd_rsp_ptr);

                switch (result) {
                case UPIU_TRANSACTION_RESPONSE:
                        /*
                         * get the response UPIU result to extract
                         * the SCSI command status
                         */
                        result = ufshcd_get_rsp_upiu_result(lrbp->ucd_rsp_ptr);

                        /*
                         * get the result based on SCSI status response
                         * to notify the SCSI midlayer of the command status
                         */
                        scsi_status = result & MASK_SCSI_STATUS;
                        result = ufshcd_scsi_cmd_status(lrbp, scsi_status);
                        break;
                case UPIU_TRANSACTION_REJECT_UPIU:
                        /* TODO: handle Reject UPIU Response */
                        result = DID_ERROR << 16;
                        dev_err(hba->dev,
                                "Reject UPIU not fully implemented\n");
                        break;
                default:
                        result = DID_ERROR << 16;
                        dev_err(hba->dev,
                                "Unexpected request response code = %x\n",
                                result);
                        break;
                }
                break;
        case OCS_ABORTED:
                result |= DID_ABORT << 16;
                break;
        case OCS_INVALID_CMD_TABLE_ATTR:
        case OCS_INVALID_PRDT_ATTR:
        case OCS_MISMATCH_DATA_BUF_SIZE:
        case OCS_MISMATCH_RESP_UPIU_SIZE:
        case OCS_PEER_COMM_FAILURE:
        case OCS_FATAL_ERROR:
        default:
                result |= DID_ERROR << 16;
                dev_err(hba->dev,
                "OCS error from controller = %x\n", ocs);
                break;
        } /* end of switch */

        return result;
}

/**
 * ufshcd_uic_cmd_compl - handle completion of uic command
 * @hba: per adapter instance
 */
static void ufshcd_uic_cmd_compl(struct ufs_hba *hba)
{
        if (hba->active_uic_cmd) {
                hba->active_uic_cmd->argument2 |=
                        ufshcd_get_uic_cmd_result(hba);
                complete(&hba->active_uic_cmd->done);
        }
}

/**
 * ufshcd_transfer_req_compl - handle SCSI and query command completion
 * @hba: per adapter instance
 */
static void ufshcd_transfer_req_compl(struct ufs_hba *hba)
{
        struct ufshcd_lrb *lrbp;
        struct scsi_cmnd *cmd;
        unsigned long completed_reqs;
        u32 tr_doorbell;
        int result;
        int index;
        bool int_aggr_reset = false;

        tr_doorbell = ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL);
        completed_reqs = tr_doorbell ^ hba->outstanding_reqs;

        for (index = 0; index < hba->nutrs; index++) {
                if (test_bit(index, &completed_reqs)) {
                        lrbp = &hba->lrb[index];
                        cmd = lrbp->cmd;
                        /*
                         * Don't skip resetting interrupt aggregation counters
                         * if a regular command is present.
                         */
                        int_aggr_reset |= !lrbp->intr_cmd;

                        if (cmd) {
                                result = ufshcd_transfer_rsp_status(hba, lrbp);
                                scsi_dma_unmap(cmd);
                                cmd->result = result;
                                /* Mark completed command as NULL in LRB */
                                lrbp->cmd = NULL;
                                clear_bit_unlock(index, &hba->lrb_in_use);
                                /* Do not touch lrbp after scsi done */
                                cmd->scsi_done(cmd);
                        } else if (lrbp->command_type ==
                                        UTP_CMD_TYPE_DEV_MANAGE) {
                                if (hba->dev_cmd.complete)
                                        complete(hba->dev_cmd.complete);
                        }
                } /* end of if */
        } /* end of for */

        /* clear corresponding bits of completed commands */
        hba->outstanding_reqs ^= completed_reqs;

        /* we might have free'd some tags above */
        wake_up(&hba->dev_cmd.tag_wq);

        /* Reset interrupt aggregation counters */
        if (int_aggr_reset)
                ufshcd_config_int_aggr(hba, INT_AGGR_RESET);
}

/**
 * ufshcd_fatal_err_handler - handle fatal errors
 * @hba: per adapter instance
 */
static void ufshcd_fatal_err_handler(struct work_struct *work)
{
        struct ufs_hba *hba;
        hba = container_of(work, struct ufs_hba, feh_workq);

        /* check if reset is already in progress */
        if (hba->ufshcd_state != UFSHCD_STATE_RESET)
                ufshcd_do_reset(hba);
}

/**
 * ufshcd_err_handler - Check for fatal errors
 * @work: pointer to a work queue structure
 */
static void ufshcd_err_handler(struct ufs_hba *hba)
{
        u32 reg;

        if (hba->errors & INT_FATAL_ERRORS)
                goto fatal_eh;

        if (hba->errors & UIC_ERROR) {
                reg = ufshcd_readl(hba, REG_UIC_ERROR_CODE_DATA_LINK_LAYER);
                if (reg & UIC_DATA_LINK_LAYER_ERROR_PA_INIT)
                        goto fatal_eh;
        }
        return;
fatal_eh:
        hba->ufshcd_state = UFSHCD_STATE_ERROR;
        schedule_work(&hba->feh_workq);
}

/**
 * ufshcd_tmc_handler - handle task management function completion
 * @hba: per adapter instance
 */
static void ufshcd_tmc_handler(struct ufs_hba *hba)
{
        u32 tm_doorbell;

        tm_doorbell = ufshcd_readl(hba, REG_UTP_TASK_REQ_DOOR_BELL);
        hba->tm_condition = tm_doorbell ^ hba->outstanding_tasks;
        wake_up_interruptible(&hba->ufshcd_tm_wait_queue);
}

/**
 * ufshcd_sl_intr - Interrupt service routine
 * @hba: per adapter instance
 * @intr_status: contains interrupts generated by the controller
 */
static void ufshcd_sl_intr(struct ufs_hba *hba, u32 intr_status)
{
        hba->errors = UFSHCD_ERROR_MASK & intr_status;
        if (hba->errors)
                ufshcd_err_handler(hba);

        if (intr_status & UIC_COMMAND_COMPL)
                ufshcd_uic_cmd_compl(hba);

        if (intr_status & UTP_TASK_REQ_COMPL)
                ufshcd_tmc_handler(hba);

        if (intr_status & UTP_TRANSFER_REQ_COMPL)
                ufshcd_transfer_req_compl(hba);
}

/**
 * ufshcd_intr - Main interrupt service routine
 * @irq: irq number
 * @__hba: pointer to adapter instance
 *
 * Returns IRQ_HANDLED - If interrupt is valid
 *              IRQ_NONE - If invalid interrupt
 */
static irqreturn_t ufshcd_intr(int irq, void *__hba)
{
        u32 intr_status;
        irqreturn_t retval = IRQ_NONE;
        struct ufs_hba *hba = __hba;

        spin_lock(hba->host->host_lock);
        intr_status = ufshcd_readl(hba, REG_INTERRUPT_STATUS);

        if (intr_status) {
                ufshcd_writel(hba, intr_status, REG_INTERRUPT_STATUS);
                ufshcd_sl_intr(hba, intr_status);
                retval = IRQ_HANDLED;
        }
        spin_unlock(hba->host->host_lock);
        return retval;
}

/**
 * ufshcd_issue_tm_cmd - issues task management commands to controller
 * @hba: per adapter instance
 * @lrbp: pointer to local reference block
 *
 * Returns SUCCESS/FAILED
 */
static int
ufshcd_issue_tm_cmd(struct ufs_hba *hba,
                    struct ufshcd_lrb *lrbp,
                    u8 tm_function)
{
        struct utp_task_req_desc *task_req_descp;
        struct utp_upiu_task_req *task_req_upiup;
        struct Scsi_Host *host;
        unsigned long flags;
        int free_slot = 0;
        int err;

        host = hba->host;

        spin_lock_irqsave(host->host_lock, flags);

        /* If task management queue is full */
        free_slot = ufshcd_get_tm_free_slot(hba);
        if (free_slot >= hba->nutmrs) {
                spin_unlock_irqrestore(host->host_lock, flags);
                dev_err(hba->dev, "Task management queue full\n");
                err = FAILED;
                goto out;
        }

        task_req_descp = hba->utmrdl_base_addr;
        task_req_descp += free_slot;

        /* Configure task request descriptor */
        task_req_descp->header.dword_0 = cpu_to_le32(UTP_REQ_DESC_INT_CMD);
        task_req_descp->header.dword_2 =
                        cpu_to_le32(OCS_INVALID_COMMAND_STATUS);

        /* Configure task request UPIU */
        task_req_upiup =
                (struct utp_upiu_task_req *) task_req_descp->task_req_upiu;
        task_req_upiup->header.dword_0 =
                UPIU_HEADER_DWORD(UPIU_TRANSACTION_TASK_REQ, 0,
                                              lrbp->lun, lrbp->task_tag);
        task_req_upiup->header.dword_1 =
                UPIU_HEADER_DWORD(0, tm_function, 0, 0);

        task_req_upiup->input_param1 = lrbp->lun;
        task_req_upiup->input_param1 =
                cpu_to_be32(task_req_upiup->input_param1);
        task_req_upiup->input_param2 = lrbp->task_tag;
        task_req_upiup->input_param2 =
                cpu_to_be32(task_req_upiup->input_param2);

        /* send command to the controller */
        __set_bit(free_slot, &hba->outstanding_tasks);
        ufshcd_writel(hba, 1 << free_slot, REG_UTP_TASK_REQ_DOOR_BELL);

        spin_unlock_irqrestore(host->host_lock, flags);

        /* wait until the task management command is completed */
        err =
        wait_event_interruptible_timeout(hba->ufshcd_tm_wait_queue,
                                         (test_bit(free_slot,
                                         &hba->tm_condition) != 0),
                                         60 * HZ);
        if (!err) {
                dev_err(hba->dev,
                        "Task management command timed-out\n");
                err = FAILED;
                goto out;
        }
        clear_bit(free_slot, &hba->tm_condition);
        err = ufshcd_task_req_compl(hba, free_slot);
out:
        return err;
}

/**
 * ufshcd_device_reset - reset device and abort all the pending commands
 * @cmd: SCSI command pointer
 *
 * Returns SUCCESS/FAILED
 */
static int ufshcd_device_reset(struct scsi_cmnd *cmd)
{
        struct Scsi_Host *host;
        struct ufs_hba *hba;
        unsigned int tag;
        u32 pos;
        int err;

        host = cmd->device->host;
        hba = shost_priv(host);
        tag = cmd->request->tag;

        err = ufshcd_issue_tm_cmd(hba, &hba->lrb[tag], UFS_LOGICAL_RESET);
        if (err == FAILED)
                goto out;

        for (pos = 0; pos < hba->nutrs; pos++) {
                if (test_bit(pos, &hba->outstanding_reqs) &&
                    (hba->lrb[tag].lun == hba->lrb[pos].lun)) {

                        /* clear the respective UTRLCLR register bit */
                        ufshcd_utrl_clear(hba, pos);

                        clear_bit(pos, &hba->outstanding_reqs);

                        if (hba->lrb[pos].cmd) {
                                scsi_dma_unmap(hba->lrb[pos].cmd);
                                hba->lrb[pos].cmd->result =
                                        DID_ABORT << 16;
                                hba->lrb[pos].cmd->scsi_done(cmd);
                                hba->lrb[pos].cmd = NULL;
                                clear_bit_unlock(pos, &hba->lrb_in_use);
                                wake_up(&hba->dev_cmd.tag_wq);
                        }
                }
        } /* end of for */
out:
        return err;
}

/**
 * ufshcd_host_reset - Main reset function registered with scsi layer
 * @cmd: SCSI command pointer
 *
 * Returns SUCCESS/FAILED
 */
static int ufshcd_host_reset(struct scsi_cmnd *cmd)
{
        struct ufs_hba *hba;

        hba = shost_priv(cmd->device->host);

        if (hba->ufshcd_state == UFSHCD_STATE_RESET)
                return SUCCESS;

        return ufshcd_do_reset(hba);
}

/**
 * ufshcd_abort - abort a specific command
 * @cmd: SCSI command pointer
 *
 * Returns SUCCESS/FAILED
 */
static int ufshcd_abort(struct scsi_cmnd *cmd)
{
        struct Scsi_Host *host;
        struct ufs_hba *hba;
        unsigned long flags;
        unsigned int tag;
        int err;

        host = cmd->device->host;
        hba = shost_priv(host);
        tag = cmd->request->tag;

        spin_lock_irqsave(host->host_lock, flags);

        /* check if command is still pending */
        if (!(test_bit(tag, &hba->outstanding_reqs))) {
                err = FAILED;
                spin_unlock_irqrestore(host->host_lock, flags);
                goto out;
        }
        spin_unlock_irqrestore(host->host_lock, flags);

        err = ufshcd_issue_tm_cmd(hba, &hba->lrb[tag], UFS_ABORT_TASK);
        if (err == FAILED)
                goto out;

        scsi_dma_unmap(cmd);

        spin_lock_irqsave(host->host_lock, flags);

        /* clear the respective UTRLCLR register bit */
        ufshcd_utrl_clear(hba, tag);

        __clear_bit(tag, &hba->outstanding_reqs);
        hba->lrb[tag].cmd = NULL;
        spin_unlock_irqrestore(host->host_lock, flags);

        clear_bit_unlock(tag, &hba->lrb_in_use);
        wake_up(&hba->dev_cmd.tag_wq);
out:
        return err;
}

/**
 * ufshcd_async_scan - asynchronous execution for link startup
 * @data: data pointer to pass to this function
 * @cookie: cookie data
 */
static void ufshcd_async_scan(void *data, async_cookie_t cookie)
{
        struct ufs_hba *hba = (struct ufs_hba *)data;
        int ret;

        ret = ufshcd_link_startup(hba);
        if (ret)
                goto out;

        ret = ufshcd_verify_dev_init(hba);
        if (ret)
                goto out;

        scsi_scan_host(hba->host);
out:
        return;
}

static struct scsi_host_template ufshcd_driver_template = {
        .module                 = THIS_MODULE,
        .name                   = UFSHCD,
        .proc_name              = UFSHCD,
        .queuecommand           = ufshcd_queuecommand,
        .slave_alloc            = ufshcd_slave_alloc,
        .slave_destroy          = ufshcd_slave_destroy,
        .eh_abort_handler       = ufshcd_abort,
        .eh_device_reset_handler = ufshcd_device_reset,
        .eh_host_reset_handler  = ufshcd_host_reset,
        .this_id                = -1,
        .sg_tablesize           = SG_ALL,
        .cmd_per_lun            = UFSHCD_CMD_PER_LUN,
        .can_queue              = UFSHCD_CAN_QUEUE,
};

/**
 * ufshcd_suspend - suspend power management function
 * @hba: per adapter instance
 * @state: power state
 *
 * Returns -ENOSYS
 */
int ufshcd_suspend(struct ufs_hba *hba, pm_message_t state)
{
        /*
         * TODO:
         * 1. Block SCSI requests from SCSI midlayer
         * 2. Change the internal driver state to non operational
         * 3. Set UTRLRSR and UTMRLRSR bits to zero
         * 4. Wait until outstanding commands are completed
         * 5. Set HCE to zero to send the UFS host controller to reset state
         */

        return -ENOSYS;
}
EXPORT_SYMBOL_GPL(ufshcd_suspend);

/**
 * ufshcd_resume - resume power management function
 * @hba: per adapter instance
 *
 * Returns -ENOSYS
 */
int ufshcd_resume(struct ufs_hba *hba)
{
        /*
         * TODO:
         * 1. Set HCE to 1, to start the UFS host controller
         * initialization process
         * 2. Set UTRLRSR and UTMRLRSR bits to 1
         * 3. Change the internal driver state to operational
         * 4. Unblock SCSI requests from SCSI midlayer
         */

        return -ENOSYS;
}
EXPORT_SYMBOL_GPL(ufshcd_resume);

/**
 * ufshcd_remove - de-allocate SCSI host and host memory space
 *              data structure memory
 * @hba - per adapter instance
 */
void ufshcd_remove(struct ufs_hba *hba)
{
        /* disable interrupts */
        ufshcd_disable_intr(hba, hba->intr_mask);
        ufshcd_hba_stop(hba);

        scsi_remove_host(hba->host);
        scsi_host_put(hba->host);
}
EXPORT_SYMBOL_GPL(ufshcd_remove);

/**
 * ufshcd_init - Driver initialization routine
 * @dev: pointer to device handle
 * @hba_handle: driver private handle
 * @mmio_base: base register address
 * @irq: Interrupt line of device
 * Returns 0 on success, non-zero value on failure
 */
int ufshcd_init(struct device *dev, struct ufs_hba **hba_handle,
                 void __iomem *mmio_base, unsigned int irq)
{
        struct Scsi_Host *host;
        struct ufs_hba *hba;
        int err;

        if (!dev) {
                dev_err(dev,
                "Invalid memory reference for dev is NULL\n");
                err = -ENODEV;
                goto out_error;
        }

        if (!mmio_base) {
                dev_err(dev,
                "Invalid memory reference for mmio_base is NULL\n");
                err = -ENODEV;
                goto out_error;
        }

        host = scsi_host_alloc(&ufshcd_driver_template,
                                sizeof(struct ufs_hba));
        if (!host) {
                dev_err(dev, "scsi_host_alloc failed\n");
                err = -ENOMEM;
                goto out_error;
        }
        hba = shost_priv(host);
        hba->host = host;
        hba->dev = dev;
        hba->mmio_base = mmio_base;
        hba->irq = irq;

        /* Read capabilities registers */
        ufshcd_hba_capabilities(hba);

        /* Get UFS version supported by the controller */
        hba->ufs_version = ufshcd_get_ufs_version(hba);

        /* Get Interrupt bit mask per version */
        hba->intr_mask = ufshcd_get_intr_mask(hba);

        /* Allocate memory for host memory space */
        err = ufshcd_memory_alloc(hba);
        if (err) {
                dev_err(hba->dev, "Memory allocation failed\n");
                goto out_disable;
        }

        /* Configure LRB */
        ufshcd_host_memory_configure(hba);

        host->can_queue = hba->nutrs;
        host->cmd_per_lun = hba->nutrs;
        host->max_id = UFSHCD_MAX_ID;
        host->max_lun = UFSHCD_MAX_LUNS;
        host->max_channel = UFSHCD_MAX_CHANNEL;
        host->unique_id = host->host_no;
        host->max_cmd_len = MAX_CDB_SIZE;

        /* Initailize wait queue for task management */
        init_waitqueue_head(&hba->ufshcd_tm_wait_queue);

        /* Initialize work queues */
        INIT_WORK(&hba->feh_workq, ufshcd_fatal_err_handler);

        /* Initialize UIC command mutex */
        mutex_init(&hba->uic_cmd_mutex);

        /* Initialize mutex for device management commands */
        mutex_init(&hba->dev_cmd.lock);

        /* Initialize device management tag acquire wait queue */
        init_waitqueue_head(&hba->dev_cmd.tag_wq);

        /* IRQ registration */
        err = devm_request_irq(dev, irq, ufshcd_intr, IRQF_SHARED, UFSHCD, hba);
        if (err) {
                dev_err(hba->dev, "request irq failed\n");
                goto out_disable;
        }

        /* Enable SCSI tag mapping */
        err = scsi_init_shared_tag_map(host, host->can_queue);
        if (err) {
                dev_err(hba->dev, "init shared queue failed\n");
                goto out_disable;
        }

        err = scsi_add_host(host, hba->dev);
        if (err) {
                dev_err(hba->dev, "scsi_add_host failed\n");
                goto out_disable;
        }

        /* Host controller enable */
        err = ufshcd_hba_enable(hba);
        if (err) {
                dev_err(hba->dev, "Host controller enable failed\n");
                goto out_remove_scsi_host;
        }

        *hba_handle = hba;

        async_schedule(ufshcd_async_scan, hba);

        return 0;

out_remove_scsi_host:
        scsi_remove_host(hba->host);
out_disable:
        scsi_host_put(host);
out_error:
        return err;
}
EXPORT_SYMBOL_GPL(ufshcd_init);

MODULE_AUTHOR("Santosh Yaragnavi <santosh.sy@samsung.com>");
MODULE_AUTHOR("Vinayak Holikatti <h.vinayak@samsung.com>");
MODULE_DESCRIPTION("Generic UFS host controller driver Core");
MODULE_LICENSE("GPL");
MODULE_VERSION(UFSHCD_DRIVER_VERSION);