// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Driver for the Micron P320 SSD
 *   Copyright (C) 2011 Micron Technology, Inc.
 *
 * Portions of this code were derived from works subjected to the
 * following copyright:
 *    Copyright (C) 2009 Integrated Device Technology, Inc.
 */

#include <linux/pci.h>
#include <linux/interrupt.h>
#include <linux/ata.h>
#include <linux/delay.h>
#include <linux/hdreg.h>
#include <linux/uaccess.h>
#include <linux/random.h>
#include <linux/smp.h>
#include <linux/compat.h>
#include <linux/fs.h>
#include <linux/module.h>
#include <linux/genhd.h>
#include <linux/blkdev.h>
#include <linux/blk-mq.h>
#include <linux/bio.h>
#include <linux/dma-mapping.h>
#include <linux/idr.h>
#include <linux/kthread.h>
#include <../drivers/ata/ahci.h>
#include <linux/export.h>
#include <linux/debugfs.h>
#include <linux/prefetch.h>
#include <linux/numa.h>
#include "mtip32xx.h"

#define HW_CMD_SLOT_SZ          (MTIP_MAX_COMMAND_SLOTS * 32)

/* DMA region containing RX Fis, Identify, RLE10, and SMART buffers */
#define AHCI_RX_FIS_SZ          0x100
#define AHCI_RX_FIS_OFFSET      0x0
#define AHCI_IDFY_SZ            ATA_SECT_SIZE
#define AHCI_IDFY_OFFSET        0x400
#define AHCI_SECTBUF_SZ         ATA_SECT_SIZE
#define AHCI_SECTBUF_OFFSET     0x800
#define AHCI_SMARTBUF_SZ        ATA_SECT_SIZE
#define AHCI_SMARTBUF_OFFSET    0xC00
/* 0x100 + 0x200 + 0x200 + 0x200 is smaller than 4k but we pad it out */
#define BLOCK_DMA_ALLOC_SZ      4096

/* DMA region containing command table (should be 8192 bytes) */
#define AHCI_CMD_SLOT_SZ        sizeof(struct mtip_cmd_hdr)
#define AHCI_CMD_TBL_SZ         (MTIP_MAX_COMMAND_SLOTS * AHCI_CMD_SLOT_SZ)
#define AHCI_CMD_TBL_OFFSET     0x0

/* DMA region per command (contains header and SGL) */
#define AHCI_CMD_TBL_HDR_SZ     0x80
#define AHCI_CMD_TBL_HDR_OFFSET 0x0
#define AHCI_CMD_TBL_SGL_SZ     (MTIP_MAX_SG * sizeof(struct mtip_cmd_sg))
#define AHCI_CMD_TBL_SGL_OFFSET AHCI_CMD_TBL_HDR_SZ
#define CMD_DMA_ALLOC_SZ        (AHCI_CMD_TBL_SGL_SZ + AHCI_CMD_TBL_HDR_SZ)


#define HOST_CAP_NZDMA          (1 << 19)
#define HOST_HSORG              0xFC
#define HSORG_DISABLE_SLOTGRP_INTR (1<<24)
#define HSORG_DISABLE_SLOTGRP_PXIS (1<<16)
#define HSORG_HWREV             0xFF00
#define HSORG_STYLE             0x8
#define HSORG_SLOTGROUPS        0x7

#define PORT_COMMAND_ISSUE      0x38
#define PORT_SDBV               0x7C

#define PORT_OFFSET             0x100
#define PORT_MEM_SIZE           0x80

#define PORT_IRQ_ERR \
        (PORT_IRQ_HBUS_ERR | PORT_IRQ_IF_ERR | PORT_IRQ_CONNECT | \
         PORT_IRQ_PHYRDY | PORT_IRQ_UNK_FIS | PORT_IRQ_BAD_PMP | \
         PORT_IRQ_TF_ERR | PORT_IRQ_HBUS_DATA_ERR | PORT_IRQ_IF_NONFATAL | \
         PORT_IRQ_OVERFLOW)
#define PORT_IRQ_LEGACY \
        (PORT_IRQ_PIOS_FIS | PORT_IRQ_D2H_REG_FIS)
#define PORT_IRQ_HANDLED \
        (PORT_IRQ_SDB_FIS | PORT_IRQ_LEGACY | \
         PORT_IRQ_TF_ERR | PORT_IRQ_IF_ERR | \
         PORT_IRQ_CONNECT | PORT_IRQ_PHYRDY)
#define DEF_PORT_IRQ \
        (PORT_IRQ_ERR | PORT_IRQ_LEGACY | PORT_IRQ_SDB_FIS)

/* product numbers */
#define MTIP_PRODUCT_UNKNOWN    0x00
#define MTIP_PRODUCT_ASICFPGA   0x11

/* Device instance number, incremented each time a device is probed. */
static int instance;

static LIST_HEAD(online_list);
static LIST_HEAD(removing_list);
static DEFINE_SPINLOCK(dev_lock);

/*
 * Global variable used to hold the major block device number
 * allocated in mtip_init().
 */
static int mtip_major;
static struct dentry *dfs_parent;
static struct dentry *dfs_device_status;

static u32 cpu_use[NR_CPUS];

static DEFINE_IDA(rssd_index_ida);

static int mtip_block_initialize(struct driver_data *dd);

#ifdef CONFIG_COMPAT
struct mtip_compat_ide_task_request_s {
        __u8            io_ports[8];
        __u8            hob_ports[8];
        ide_reg_valid_t out_flags;
        ide_reg_valid_t in_flags;
        int             data_phase;
        int             req_cmd;
        compat_ulong_t  out_size;
        compat_ulong_t  in_size;
};
#endif

/*
 * This function check_for_surprise_removal is called
 * while card is removed from the system and it will
 * read the vendor id from the configuration space
 *
 * @pdev Pointer to the pci_dev structure.
 *
 * return value
 *       true if device removed, else false
 */
static bool mtip_check_surprise_removal(struct pci_dev *pdev)
{
        u16 vendor_id = 0;
        struct driver_data *dd = pci_get_drvdata(pdev);

        if (dd->sr)
                return true;

       /* Read the vendorID from the configuration space */
        pci_read_config_word(pdev, 0x00, &vendor_id);
        if (vendor_id == 0xFFFF) {
                dd->sr = true;
                if (dd->queue)
                        blk_queue_flag_set(QUEUE_FLAG_DEAD, dd->queue);
                else
                        dev_warn(&dd->pdev->dev,
                                "%s: dd->queue is NULL\n", __func__);
                return true; /* device removed */
        }

        return false; /* device present */
}

static struct mtip_cmd *mtip_cmd_from_tag(struct driver_data *dd,
                                          unsigned int tag)
{
        struct blk_mq_hw_ctx *hctx = dd->queue->queue_hw_ctx[0];

        return blk_mq_rq_to_pdu(blk_mq_tag_to_rq(hctx->tags, tag));
}

/*
 * Reset the HBA (without sleeping)
 *
 * @dd Pointer to the driver data structure.
 *
 * return value
 *      0       The reset was successful.
 *      -1      The HBA Reset bit did not clear.
 */
static int mtip_hba_reset(struct driver_data *dd)
{
        unsigned long timeout;

        /* Set the reset bit */
        writel(HOST_RESET, dd->mmio + HOST_CTL);

        /* Flush */
        readl(dd->mmio + HOST_CTL);

        /*
         * Spin for up to 10 seconds waiting for reset acknowledgement. Spec
         * is 1 sec but in LUN failure conditions, up to 10 secs are required
         */
        timeout = jiffies + msecs_to_jiffies(10000);
        do {
                mdelay(10);
                if (test_bit(MTIP_DDF_REMOVE_PENDING_BIT, &dd->dd_flag))
                        return -1;

        } while ((readl(dd->mmio + HOST_CTL) & HOST_RESET)
                 && time_before(jiffies, timeout));

        if (readl(dd->mmio + HOST_CTL) & HOST_RESET)
                return -1;

        return 0;
}

/*
 * Issue a command to the hardware.
 *
 * Set the appropriate bit in the s_active and Command Issue hardware
 * registers, causing hardware command processing to begin.
 *
 * @port Pointer to the port structure.
 * @tag  The tag of the command to be issued.
 *
 * return value
 *      None
 */
static inline void mtip_issue_ncq_command(struct mtip_port *port, int tag)
{
        int group = tag >> 5;

        /* guard SACT and CI registers */
        spin_lock(&port->cmd_issue_lock[group]);
        writel((1 << MTIP_TAG_BIT(tag)),
                        port->s_active[MTIP_TAG_INDEX(tag)]);
        writel((1 << MTIP_TAG_BIT(tag)),
                        port->cmd_issue[MTIP_TAG_INDEX(tag)]);
        spin_unlock(&port->cmd_issue_lock[group]);
}

/*
 * Enable/disable the reception of FIS
 *
 * @port   Pointer to the port data structure
 * @enable 1 to enable, 0 to disable
 *
 * return value
 *      Previous state: 1 enabled, 0 disabled
 */
static int mtip_enable_fis(struct mtip_port *port, int enable)
{
        u32 tmp;

        /* enable FIS reception */
        tmp = readl(port->mmio + PORT_CMD);
        if (enable)
                writel(tmp | PORT_CMD_FIS_RX, port->mmio + PORT_CMD);
        else
                writel(tmp & ~PORT_CMD_FIS_RX, port->mmio + PORT_CMD);

        /* Flush */
        readl(port->mmio + PORT_CMD);

        return (((tmp & PORT_CMD_FIS_RX) == PORT_CMD_FIS_RX));
}

/*
 * Enable/disable the DMA engine
 *
 * @port   Pointer to the port data structure
 * @enable 1 to enable, 0 to disable
 *
 * return value
 *      Previous state: 1 enabled, 0 disabled.
 */
static int mtip_enable_engine(struct mtip_port *port, int enable)
{
        u32 tmp;

        /* enable FIS reception */
        tmp = readl(port->mmio + PORT_CMD);
        if (enable)
                writel(tmp | PORT_CMD_START, port->mmio + PORT_CMD);
        else
                writel(tmp & ~PORT_CMD_START, port->mmio + PORT_CMD);

        readl(port->mmio + PORT_CMD);
        return (((tmp & PORT_CMD_START) == PORT_CMD_START));
}

/*
 * Enables the port DMA engine and FIS reception.
 *
 * return value
 *      None
 */
static inline void mtip_start_port(struct mtip_port *port)
{
        /* Enable FIS reception */
        mtip_enable_fis(port, 1);

        /* Enable the DMA engine */
        mtip_enable_engine(port, 1);
}

/*
 * Deinitialize a port by disabling port interrupts, the DMA engine,
 * and FIS reception.
 *
 * @port Pointer to the port structure
 *
 * return value
 *      None
 */
static inline void mtip_deinit_port(struct mtip_port *port)
{
        /* Disable interrupts on this port */
        writel(0, port->mmio + PORT_IRQ_MASK);

        /* Disable the DMA engine */
        mtip_enable_engine(port, 0);

        /* Disable FIS reception */
        mtip_enable_fis(port, 0);
}

/*
 * Initialize a port.
 *
 * This function deinitializes the port by calling mtip_deinit_port() and
 * then initializes it by setting the command header and RX FIS addresses,
 * clearing the SError register and any pending port interrupts before
 * re-enabling the default set of port interrupts.
 *
 * @port Pointer to the port structure.
 *
 * return value
 *      None
 */
static void mtip_init_port(struct mtip_port *port)
{
        int i;
        mtip_deinit_port(port);

        /* Program the command list base and FIS base addresses */
        if (readl(port->dd->mmio + HOST_CAP) & HOST_CAP_64) {
                writel((port->command_list_dma >> 16) >> 16,
                         port->mmio + PORT_LST_ADDR_HI);
                writel((port->rxfis_dma >> 16) >> 16,
                         port->mmio + PORT_FIS_ADDR_HI);
                set_bit(MTIP_PF_HOST_CAP_64, &port->flags);
        }

        writel(port->command_list_dma & 0xFFFFFFFF,
                        port->mmio + PORT_LST_ADDR);
        writel(port->rxfis_dma & 0xFFFFFFFF, port->mmio + PORT_FIS_ADDR);

        /* Clear SError */
        writel(readl(port->mmio + PORT_SCR_ERR), port->mmio + PORT_SCR_ERR);

        /* reset the completed registers.*/
        for (i = 0; i < port->dd->slot_groups; i++)
                writel(0xFFFFFFFF, port->completed[i]);

        /* Clear any pending interrupts for this port */
        writel(readl(port->mmio + PORT_IRQ_STAT), port->mmio + PORT_IRQ_STAT);

        /* Clear any pending interrupts on the HBA. */
        writel(readl(port->dd->mmio + HOST_IRQ_STAT),
                                        port->dd->mmio + HOST_IRQ_STAT);

        /* Enable port interrupts */
        writel(DEF_PORT_IRQ, port->mmio + PORT_IRQ_MASK);
}

/*
 * Restart a port
 *
 * @port Pointer to the port data structure.
 *
 * return value
 *      None
 */
static void mtip_restart_port(struct mtip_port *port)
{
        unsigned long timeout;

        /* Disable the DMA engine */
        mtip_enable_engine(port, 0);

        /* Chip quirk: wait up to 500ms for PxCMD.CR == 0 */
        timeout = jiffies + msecs_to_jiffies(500);
        while ((readl(port->mmio + PORT_CMD) & PORT_CMD_LIST_ON)
                 && time_before(jiffies, timeout))
                ;

        if (test_bit(MTIP_DDF_REMOVE_PENDING_BIT, &port->dd->dd_flag))
                return;

        /*
         * Chip quirk: escalate to hba reset if
         * PxCMD.CR not clear after 500 ms
         */
        if (readl(port->mmio + PORT_CMD) & PORT_CMD_LIST_ON) {
                dev_warn(&port->dd->pdev->dev,
                        "PxCMD.CR not clear, escalating reset\n");

                if (mtip_hba_reset(port->dd))
                        dev_err(&port->dd->pdev->dev,
                                "HBA reset escalation failed.\n");

                /* 30 ms delay before com reset to quiesce chip */
                mdelay(30);
        }

        dev_warn(&port->dd->pdev->dev, "Issuing COM reset\n");

        /* Set PxSCTL.DET */
        writel(readl(port->mmio + PORT_SCR_CTL) |
                         1, port->mmio + PORT_SCR_CTL);
        readl(port->mmio + PORT_SCR_CTL);

        /* Wait 1 ms to quiesce chip function */
        timeout = jiffies + msecs_to_jiffies(1);
        while (time_before(jiffies, timeout))
                ;

        if (test_bit(MTIP_DDF_REMOVE_PENDING_BIT, &port->dd->dd_flag))
                return;

        /* Clear PxSCTL.DET */
        writel(readl(port->mmio + PORT_SCR_CTL) & ~1,
                         port->mmio + PORT_SCR_CTL);
        readl(port->mmio + PORT_SCR_CTL);

        /* Wait 500 ms for bit 0 of PORT_SCR_STS to be set */
        timeout = jiffies + msecs_to_jiffies(500);
        while (((readl(port->mmio + PORT_SCR_STAT) & 0x01) == 0)
                         && time_before(jiffies, timeout))
                ;

        if (test_bit(MTIP_DDF_REMOVE_PENDING_BIT, &port->dd->dd_flag))
                return;

        if ((readl(port->mmio + PORT_SCR_STAT) & 0x01) == 0)
                dev_warn(&port->dd->pdev->dev,
                        "COM reset failed\n");

        mtip_init_port(port);
        mtip_start_port(port);

}

static int mtip_device_reset(struct driver_data *dd)
{
        int rv = 0;

        if (mtip_check_surprise_removal(dd->pdev))
                return 0;

        if (mtip_hba_reset(dd) < 0)
                rv = -EFAULT;

        mdelay(1);
        mtip_init_port(dd->port);
        mtip_start_port(dd->port);

        /* Enable interrupts on the HBA. */
        writel(readl(dd->mmio + HOST_CTL) | HOST_IRQ_EN,
                                        dd->mmio + HOST_CTL);
        return rv;
}

/*
 * Helper function for tag logging
 */
static void print_tags(struct driver_data *dd,
                        char *msg,
                        unsigned long *tagbits,
                        int cnt)
{
        unsigned char tagmap[128];
        int group, tagmap_len = 0;

        memset(tagmap, 0, sizeof(tagmap));
        for (group = SLOTBITS_IN_LONGS; group > 0; group--)
                tagmap_len += sprintf(tagmap + tagmap_len, "%016lX ",
                                                tagbits[group-1]);
        dev_warn(&dd->pdev->dev,
                        "%d command(s) %s: tagmap [%s]", cnt, msg, tagmap);
}

static int mtip_read_log_page(struct mtip_port *port, u8 page, u16 *buffer,
                                dma_addr_t buffer_dma, unsigned int sectors);
static int mtip_get_smart_attr(struct mtip_port *port, unsigned int id,
                                                struct smart_attr *attrib);

static void mtip_complete_command(struct mtip_cmd *cmd, blk_status_t status)
{
        struct request *req = blk_mq_rq_from_pdu(cmd);

        cmd->status = status;
        if (likely(!blk_should_fake_timeout(req->q)))
                blk_mq_complete_request(req);
}

/*
 * Handle an error.
 *
 * @dd Pointer to the DRIVER_DATA structure.
 *
 * return value
 *      None
 */
static void mtip_handle_tfe(struct driver_data *dd)
{
        int group, tag, bit, reissue, rv;
        struct mtip_port *port;
        struct mtip_cmd  *cmd;
        u32 completed;
        struct host_to_dev_fis *fis;
        unsigned long tagaccum[SLOTBITS_IN_LONGS];
        unsigned int cmd_cnt = 0;
        unsigned char *buf;
        char *fail_reason = NULL;
        int fail_all_ncq_write = 0, fail_all_ncq_cmds = 0;

        dev_warn(&dd->pdev->dev, "Taskfile error\n");

        port = dd->port;

        if (test_bit(MTIP_PF_IC_ACTIVE_BIT, &port->flags)) {
                cmd = mtip_cmd_from_tag(dd, MTIP_TAG_INTERNAL);
                dbg_printk(MTIP_DRV_NAME " TFE for the internal command\n");
                mtip_complete_command(cmd, BLK_STS_IOERR);
                return;
        }

        /* clear the tag accumulator */
        memset(tagaccum, 0, SLOTBITS_IN_LONGS * sizeof(long));

        /* Loop through all the groups */
        for (group = 0; group < dd->slot_groups; group++) {
                completed = readl(port->completed[group]);

                dev_warn(&dd->pdev->dev, "g=%u, comp=%x\n", group, completed);

                /* clear completed status register in the hardware.*/
                writel(completed, port->completed[group]);

                /* Process successfully completed commands */
                for (bit = 0; bit < 32 && completed; bit++) {
                        if (!(completed & (1<<bit)))
                                continue;
                        tag = (group << 5) + bit;

                        /* Skip the internal command slot */
                        if (tag == MTIP_TAG_INTERNAL)
                                continue;

                        cmd = mtip_cmd_from_tag(dd, tag);
                        mtip_complete_command(cmd, 0);
                        set_bit(tag, tagaccum);
                        cmd_cnt++;
                }
        }

        print_tags(dd, "completed (TFE)", tagaccum, cmd_cnt);

        /* Restart the port */
        mdelay(20);
        mtip_restart_port(port);

        /* Trying to determine the cause of the error */
        rv = mtip_read_log_page(dd->port, ATA_LOG_SATA_NCQ,
                                dd->port->log_buf,
                                dd->port->log_buf_dma, 1);
        if (rv) {
                dev_warn(&dd->pdev->dev,
                        "Error in READ LOG EXT (10h) command\n");
                /* non-critical error, don't fail the load */
        } else {
                buf = (unsigned char *)dd->port->log_buf;
                if (buf[259] & 0x1) {
                        dev_info(&dd->pdev->dev,
                                "Write protect bit is set.\n");
                        set_bit(MTIP_DDF_WRITE_PROTECT_BIT, &dd->dd_flag);
                        fail_all_ncq_write = 1;
                        fail_reason = "write protect";
                }
                if (buf[288] == 0xF7) {
                        dev_info(&dd->pdev->dev,
                                "Exceeded Tmax, drive in thermal shutdown.\n");
                        set_bit(MTIP_DDF_OVER_TEMP_BIT, &dd->dd_flag);
                        fail_all_ncq_cmds = 1;
                        fail_reason = "thermal shutdown";
                }
                if (buf[288] == 0xBF) {
                        set_bit(MTIP_DDF_REBUILD_FAILED_BIT, &dd->dd_flag);
                        dev_info(&dd->pdev->dev,
                                "Drive indicates rebuild has failed. Secure erase required.\n");
                        fail_all_ncq_cmds = 1;
                        fail_reason = "rebuild failed";
                }
        }

        /* clear the tag accumulator */
        memset(tagaccum, 0, SLOTBITS_IN_LONGS * sizeof(long));

        /* Loop through all the groups */
        for (group = 0; group < dd->slot_groups; group++) {
                for (bit = 0; bit < 32; bit++) {
                        reissue = 1;
                        tag = (group << 5) + bit;
                        cmd = mtip_cmd_from_tag(dd, tag);

                        fis = (struct host_to_dev_fis *)cmd->command;

                        /* Should re-issue? */
                        if (tag == MTIP_TAG_INTERNAL ||
                            fis->command == ATA_CMD_SET_FEATURES)
                                reissue = 0;
                        else {
                                if (fail_all_ncq_cmds ||
                                        (fail_all_ncq_write &&
                                        fis->command == ATA_CMD_FPDMA_WRITE)) {
                                        dev_warn(&dd->pdev->dev,
                                        "  Fail: %s w/tag %d [%s].\n",
                                        fis->command == ATA_CMD_FPDMA_WRITE ?
                                                "write" : "read",
                                        tag,
                                        fail_reason != NULL ?
                                                fail_reason : "unknown");
                                        mtip_complete_command(cmd, BLK_STS_MEDIUM);
                                        continue;
                                }
                        }

                        /*
                         * First check if this command has
                         *  exceeded its retries.
                         */
                        if (reissue && (cmd->retries-- > 0)) {

                                set_bit(tag, tagaccum);

                                /* Re-issue the command. */
                                mtip_issue_ncq_command(port, tag);

                                continue;
                        }

                        /* Retire a command that will not be reissued */
                        dev_warn(&port->dd->pdev->dev,
                                "retiring tag %d\n", tag);

                        mtip_complete_command(cmd, BLK_STS_IOERR);
                }
        }
        print_tags(dd, "reissued (TFE)", tagaccum, cmd_cnt);
}

/*
 * Handle a set device bits interrupt
 */
static inline void mtip_workq_sdbfx(struct mtip_port *port, int group,
                                                        u32 completed)
{
        struct driver_data *dd = port->dd;
        int tag, bit;
        struct mtip_cmd *command;

        if (!completed) {
                WARN_ON_ONCE(!completed);
                return;
        }
        /* clear completed status register in the hardware.*/
        writel(completed, port->completed[group]);

        /* Process completed commands. */
        for (bit = 0; (bit < 32) && completed; bit++) {
                if (completed & 0x01) {
                        tag = (group << 5) | bit;

                        /* skip internal command slot. */
                        if (unlikely(tag == MTIP_TAG_INTERNAL))
                                continue;

                        command = mtip_cmd_from_tag(dd, tag);
                        mtip_complete_command(command, 0);
                }
                completed >>= 1;
        }

        /* If last, re-enable interrupts */
        if (atomic_dec_return(&dd->irq_workers_active) == 0)
                writel(0xffffffff, dd->mmio + HOST_IRQ_STAT);
}

/*
 * Process legacy pio and d2h interrupts
 */
static inline void mtip_process_legacy(struct driver_data *dd, u32 port_stat)
{
        struct mtip_port *port = dd->port;
        struct mtip_cmd *cmd = mtip_cmd_from_tag(dd, MTIP_TAG_INTERNAL);

        if (test_bit(MTIP_PF_IC_ACTIVE_BIT, &port->flags) && cmd) {
                int group = MTIP_TAG_INDEX(MTIP_TAG_INTERNAL);
                int status = readl(port->cmd_issue[group]);

                if (!(status & (1 << MTIP_TAG_BIT(MTIP_TAG_INTERNAL))))
                        mtip_complete_command(cmd, 0);
        }
}

/*
 * Demux and handle errors
 */
static inline void mtip_process_errors(struct driver_data *dd, u32 port_stat)
{
        if (unlikely(port_stat & PORT_IRQ_CONNECT)) {
                dev_warn(&dd->pdev->dev,
                        "Clearing PxSERR.DIAG.x\n");
                writel((1 << 26), dd->port->mmio + PORT_SCR_ERR);
        }

        if (unlikely(port_stat & PORT_IRQ_PHYRDY)) {
                dev_warn(&dd->pdev->dev,
                        "Clearing PxSERR.DIAG.n\n");
                writel((1 << 16), dd->port->mmio + PORT_SCR_ERR);
        }

        if (unlikely(port_stat & ~PORT_IRQ_HANDLED)) {
                dev_warn(&dd->pdev->dev,
                        "Port stat errors %x unhandled\n",
                        (port_stat & ~PORT_IRQ_HANDLED));
                if (mtip_check_surprise_removal(dd->pdev))
                        return;
        }
        if (likely(port_stat & (PORT_IRQ_TF_ERR | PORT_IRQ_IF_ERR))) {
                set_bit(MTIP_PF_EH_ACTIVE_BIT, &dd->port->flags);
                wake_up_interruptible(&dd->port->svc_wait);
        }
}

static inline irqreturn_t mtip_handle_irq(struct driver_data *data)
{
        struct driver_data *dd = (struct driver_data *) data;
        struct mtip_port *port = dd->port;
        u32 hba_stat, port_stat;
        int rv = IRQ_NONE;
        int do_irq_enable = 1, i, workers;
        struct mtip_work *twork;

        hba_stat = readl(dd->mmio + HOST_IRQ_STAT);
        if (hba_stat) {
                rv = IRQ_HANDLED;

                /* Acknowledge the interrupt status on the port.*/
                port_stat = readl(port->mmio + PORT_IRQ_STAT);
                if (unlikely(port_stat == 0xFFFFFFFF)) {
                        mtip_check_surprise_removal(dd->pdev);
                        return IRQ_HANDLED;
                }
                writel(port_stat, port->mmio + PORT_IRQ_STAT);

                /* Demux port status */
                if (likely(port_stat & PORT_IRQ_SDB_FIS)) {
                        do_irq_enable = 0;
                        WARN_ON_ONCE(atomic_read(&dd->irq_workers_active) != 0);

                        /* Start at 1: group zero is always local? */
                        for (i = 0, workers = 0; i < MTIP_MAX_SLOT_GROUPS;
                                                                        i++) {
                                twork = &dd->work[i];
                                twork->completed = readl(port->completed[i]);
                                if (twork->completed)
                                        workers++;
                        }

                        atomic_set(&dd->irq_workers_active, workers);
                        if (workers) {
                                for (i = 1; i < MTIP_MAX_SLOT_GROUPS; i++) {
                                        twork = &dd->work[i];
                                        if (twork->completed)
                                                queue_work_on(
                                                        twork->cpu_binding,
                                                        dd->isr_workq,
                                                        &twork->work);
                                }

                                if (likely(dd->work[0].completed))
                                        mtip_workq_sdbfx(port, 0,
                                                        dd->work[0].completed);

                        } else {
                                /*
                                 * Chip quirk: SDB interrupt but nothing
                                 * to complete
                                 */
                                do_irq_enable = 1;
                        }
                }

                if (unlikely(port_stat & PORT_IRQ_ERR)) {
                        if (unlikely(mtip_check_surprise_removal(dd->pdev))) {
                                /* don't proceed further */
                                return IRQ_HANDLED;
                        }
                        if (test_bit(MTIP_DDF_REMOVE_PENDING_BIT,
                                                        &dd->dd_flag))
                                return rv;

                        mtip_process_errors(dd, port_stat & PORT_IRQ_ERR);
                }

                if (unlikely(port_stat & PORT_IRQ_LEGACY))
                        mtip_process_legacy(dd, port_stat & PORT_IRQ_LEGACY);
        }

        /* acknowledge interrupt */
        if (unlikely(do_irq_enable))
                writel(hba_stat, dd->mmio + HOST_IRQ_STAT);

        return rv;
}

/*
 * HBA interrupt subroutine.
 *
 * @irq         IRQ number.
 * @instance    Pointer to the driver data structure.
 *
 * return value
 *      IRQ_HANDLED     A HBA interrupt was pending and handled.
 *      IRQ_NONE        This interrupt was not for the HBA.
 */
static irqreturn_t mtip_irq_handler(int irq, void *instance)
{
        struct driver_data *dd = instance;

        return mtip_handle_irq(dd);
}

static void mtip_issue_non_ncq_command(struct mtip_port *port, int tag)
{
        writel(1 << MTIP_TAG_BIT(tag), port->cmd_issue[MTIP_TAG_INDEX(tag)]);
}

static bool mtip_pause_ncq(struct mtip_port *port,
                                struct host_to_dev_fis *fis)
{
        unsigned long task_file_data;

        task_file_data = readl(port->mmio+PORT_TFDATA);
        if ((task_file_data & 1))
                return false;

        if (fis->command == ATA_CMD_SEC_ERASE_PREP) {
                port->ic_pause_timer = jiffies;
                return true;
        } else if ((fis->command == ATA_CMD_DOWNLOAD_MICRO) &&
                                        (fis->features == 0x03)) {
                set_bit(MTIP_PF_DM_ACTIVE_BIT, &port->flags);
                port->ic_pause_timer = jiffies;
                return true;
        } else if ((fis->command == ATA_CMD_SEC_ERASE_UNIT) ||
                ((fis->command == 0xFC) &&
                        (fis->features == 0x27 || fis->features == 0x72 ||
                         fis->features == 0x62 || fis->features == 0x26))) {
                clear_bit(MTIP_DDF_SEC_LOCK_BIT, &port->dd->dd_flag);
                clear_bit(MTIP_DDF_REBUILD_FAILED_BIT, &port->dd->dd_flag);
                /* Com reset after secure erase or lowlevel format */
                mtip_restart_port(port);
                clear_bit(MTIP_PF_SE_ACTIVE_BIT, &port->flags);
                return false;
        }

        return false;
}

static bool mtip_commands_active(struct mtip_port *port)
{
        unsigned int active;
        unsigned int n;

        /*
         * Ignore s_active bit 0 of array element 0.
         * This bit will always be set
         */
        active = readl(port->s_active[0]) & 0xFFFFFFFE;
        for (n = 1; n < port->dd->slot_groups; n++)
                active |= readl(port->s_active[n]);

        return active != 0;
}

/*
 * Wait for port to quiesce
 *
 * @port    Pointer to port data structure
 * @timeout Max duration to wait (ms)
 *
 * return value
 *      0       Success
 *      -EBUSY  Commands still active
 */
static int mtip_quiesce_io(struct mtip_port *port, unsigned long timeout)
{
        unsigned long to;
        bool active = true;

        blk_mq_quiesce_queue(port->dd->queue);

        to = jiffies + msecs_to_jiffies(timeout);
        do {
                if (test_bit(MTIP_PF_SVC_THD_ACTIVE_BIT, &port->flags) &&
                        test_bit(MTIP_PF_ISSUE_CMDS_BIT, &port->flags)) {
                        msleep(20);
                        continue; /* svc thd is actively issuing commands */
                }

                msleep(100);

                if (mtip_check_surprise_removal(port->dd->pdev))
                        goto err_fault;

                active = mtip_commands_active(port);
                if (!active)
                        break;
        } while (time_before(jiffies, to));

        blk_mq_unquiesce_queue(port->dd->queue);
        return active ? -EBUSY : 0;
err_fault:
        blk_mq_unquiesce_queue(port->dd->queue);
        return -EFAULT;
}

struct mtip_int_cmd {
        int fis_len;
        dma_addr_t buffer;
        int buf_len;
        u32 opts;
};

/*
 * Execute an internal command and wait for the completion.
 *
 * @port    Pointer to the port data structure.
 * @fis     Pointer to the FIS that describes the command.
 * @fis_len  Length in WORDS of the FIS.
 * @buffer  DMA accessible for command data.
 * @buf_len  Length, in bytes, of the data buffer.
 * @opts    Command header options, excluding the FIS length
 *             and the number of PRD entries.
 * @timeout Time in ms to wait for the command to complete.
 *
 * return value
 *      0        Command completed successfully.
 *      -EFAULT  The buffer address is not correctly aligned.
 *      -EBUSY   Internal command or other IO in progress.
 *      -EAGAIN  Time out waiting for command to complete.
 */
static int mtip_exec_internal_command(struct mtip_port *port,
                                        struct host_to_dev_fis *fis,
                                        int fis_len,
                                        dma_addr_t buffer,
                                        int buf_len,
                                        u32 opts,
                                        unsigned long timeout)
{
        struct mtip_cmd *int_cmd;
        struct driver_data *dd = port->dd;
        struct request *rq;
        struct mtip_int_cmd icmd = {
                .fis_len = fis_len,
                .buffer = buffer,
                .buf_len = buf_len,
                .opts = opts
        };
        int rv = 0;

        /* Make sure the buffer is 8 byte aligned. This is asic specific. */
        if (buffer & 0x00000007) {
                dev_err(&dd->pdev->dev, "SG buffer is not 8 byte aligned\n");
                return -EFAULT;
        }

        if (mtip_check_surprise_removal(dd->pdev))
                return -EFAULT;

        rq = blk_mq_alloc_request(dd->queue, REQ_OP_DRV_IN, BLK_MQ_REQ_RESERVED);
        if (IS_ERR(rq)) {
                dbg_printk(MTIP_DRV_NAME "Unable to allocate tag for PIO cmd\n");
                return -EFAULT;
        }

        set_bit(MTIP_PF_IC_ACTIVE_BIT, &port->flags);

        if (fis->command == ATA_CMD_SEC_ERASE_PREP)
                set_bit(MTIP_PF_SE_ACTIVE_BIT, &port->flags);

        clear_bit(MTIP_PF_DM_ACTIVE_BIT, &port->flags);

        if (fis->command != ATA_CMD_STANDBYNOW1) {
                /* wait for io to complete if non atomic */

                if (mtip_quiesce_io(port, MTIP_QUIESCE_IO_TIMEOUT_MS) < 0) {
                        dev_warn(&dd->pdev->dev, "Failed to quiesce IO\n");
                        blk_mq_free_request(rq);
                        clear_bit(MTIP_PF_IC_ACTIVE_BIT, &port->flags);
                        wake_up_interruptible(&port->svc_wait);
                        return -EBUSY;
                }
        }

        /* Copy the command to the command table */
        int_cmd = blk_mq_rq_to_pdu(rq);
        int_cmd->icmd = &icmd;
        memcpy(int_cmd->command, fis, fis_len*4);

        rq->timeout = timeout;

        /* insert request and run queue */
        blk_execute_rq(NULL, rq, true);

        if (int_cmd->status) {
                dev_err(&dd->pdev->dev, "Internal command [%02X] failed %d\n",
                                fis->command, int_cmd->status);
                rv = -EIO;

                if (mtip_check_surprise_removal(dd->pdev) ||
                        test_bit(MTIP_DDF_REMOVE_PENDING_BIT,
                                        &dd->dd_flag)) {
                        dev_err(&dd->pdev->dev,
                                "Internal command [%02X] wait returned due to SR\n",
                                fis->command);
                        rv = -ENXIO;
                        goto exec_ic_exit;
                }
                mtip_device_reset(dd); /* recover from timeout issue */
                rv = -EAGAIN;
                goto exec_ic_exit;
        }

        if (readl(port->cmd_issue[MTIP_TAG_INDEX(MTIP_TAG_INTERNAL)])
                        & (1 << MTIP_TAG_BIT(MTIP_TAG_INTERNAL))) {
                rv = -ENXIO;
                if (!test_bit(MTIP_DDF_REMOVE_PENDING_BIT, &dd->dd_flag)) {
                        mtip_device_reset(dd);
                        rv = -EAGAIN;
                }
        }
exec_ic_exit:
        /* Clear the allocated and active bits for the internal command. */
        blk_mq_free_request(rq);
        clear_bit(MTIP_PF_IC_ACTIVE_BIT, &port->flags);
        if (rv >= 0 && mtip_pause_ncq(port, fis)) {
                /* NCQ paused */
                return rv;
        }
        wake_up_interruptible(&port->svc_wait);

        return rv;
}

/*
 * Byte-swap ATA ID strings.
 *
 * ATA identify data contains strings in byte-swapped 16-bit words.
 * They must be swapped (on all architectures) to be usable as C strings.
 * This function swaps bytes in-place.
 *
 * @buf The buffer location of the string
 * @len The number of bytes to swap
 *
 * return value
 *      None
 */
static inline void ata_swap_string(u16 *buf, unsigned int len)
{
        int i;
        for (i = 0; i < (len/2); i++)
                be16_to_cpus(&buf[i]);
}

static void mtip_set_timeout(struct driver_data *dd,
                                        struct host_to_dev_fis *fis,
                                        unsigned int *timeout, u8 erasemode)
{
        switch (fis->command) {
        case ATA_CMD_DOWNLOAD_MICRO:
                *timeout = 120000; /* 2 minutes */
                break;
        case ATA_CMD_SEC_ERASE_UNIT:
        case 0xFC:
                if (erasemode)
                        *timeout = ((*(dd->port->identify + 90) * 2) * 60000);
                else
                        *timeout = ((*(dd->port->identify + 89) * 2) * 60000);
                break;
        case ATA_CMD_STANDBYNOW1:
                *timeout = 120000;  /* 2 minutes */
                break;
        case 0xF7:
        case 0xFA:
                *timeout = 60000;  /* 60 seconds */
                break;
        case ATA_CMD_SMART:
                *timeout = 15000;  /* 15 seconds */
                break;
        default:
                *timeout = MTIP_IOCTL_CMD_TIMEOUT_MS;
                break;
        }
}

/*
 * Request the device identity information.
 *
 * If a user space buffer is not specified, i.e. is NULL, the
 * identify information is still read from the drive and placed
 * into the identify data buffer (@e port->identify) in the
 * port data structure.
 * When the identify buffer contains valid identify information @e
 * port->identify_valid is non-zero.
 *
 * @port         Pointer to the port structure.
 * @user_buffer  A user space buffer where the identify data should be
 *                    copied.
 *
 * return value
 *      0       Command completed successfully.
 *      -EFAULT An error occurred while coping data to the user buffer.
 *      -1      Command failed.
 */
static int mtip_get_identify(struct mtip_port *port, void __user *user_buffer)
{
        int rv = 0;
        struct host_to_dev_fis fis;

        if (test_bit(MTIP_DDF_REMOVE_PENDING_BIT, &port->dd->dd_flag))
                return -EFAULT;

        /* Build the FIS. */
        memset(&fis, 0, sizeof(struct host_to_dev_fis));
        fis.type        = 0x27;
        fis.opts        = 1 << 7;
        fis.command     = ATA_CMD_ID_ATA;

        /* Set the identify information as invalid. */
        port->identify_valid = 0;

        /* Clear the identify information. */
        memset(port->identify, 0, sizeof(u16) * ATA_ID_WORDS);

        /* Execute the command. */
        if (mtip_exec_internal_command(port,
                                &fis,
                                5,
                                port->identify_dma,
                                sizeof(u16) * ATA_ID_WORDS,
                                0,
                                MTIP_INT_CMD_TIMEOUT_MS)
                                < 0) {
                rv = -1;
                goto out;
        }

        /*
         * Perform any necessary byte-swapping.  Yes, the kernel does in fact
         * perform field-sensitive swapping on the string fields.
         * See the kernel use of ata_id_string() for proof of this.
         */
#ifdef __LITTLE_ENDIAN
        ata_swap_string(port->identify + 27, 40);  /* model string*/
        ata_swap_string(port->identify + 23, 8);   /* firmware string*/
        ata_swap_string(port->identify + 10, 20);  /* serial# string*/
#else
        {
                int i;
                for (i = 0; i < ATA_ID_WORDS; i++)
                        port->identify[i] = le16_to_cpu(port->identify[i]);
        }
#endif

        /* Check security locked state */
        if (port->identify[128] & 0x4)
                set_bit(MTIP_DDF_SEC_LOCK_BIT, &port->dd->dd_flag);
        else
                clear_bit(MTIP_DDF_SEC_LOCK_BIT, &port->dd->dd_flag);

        /* Set the identify buffer as valid. */
        port->identify_valid = 1;

        if (user_buffer) {
                if (copy_to_user(
                        user_buffer,
                        port->identify,
                        ATA_ID_WORDS * sizeof(u16))) {
                        rv = -EFAULT;
                        goto out;
                }
        }

out:
        return rv;
}

/*
 * Issue a standby immediate command to the device.
 *
 * @port Pointer to the port structure.
 *
 * return value
 *      0       Command was executed successfully.
 *      -1      An error occurred while executing the command.
 */
static int mtip_standby_immediate(struct mtip_port *port)
{
        int rv;
        struct host_to_dev_fis  fis;
        unsigned long __maybe_unused start;
        unsigned int timeout;

        /* Build the FIS. */
        memset(&fis, 0, sizeof(struct host_to_dev_fis));
        fis.type        = 0x27;
        fis.opts        = 1 << 7;
        fis.command     = ATA_CMD_STANDBYNOW1;

        mtip_set_timeout(port->dd, &fis, &timeout, 0);

        start = jiffies;
        rv = mtip_exec_internal_command(port,
                                        &fis,
                                        5,
                                        0,
                                        0,
                                        0,
                                        timeout);
        dbg_printk(MTIP_DRV_NAME "Time taken to complete standby cmd: %d ms\n",
                        jiffies_to_msecs(jiffies - start));
        if (rv)
                dev_warn(&port->dd->pdev->dev,
                        "STANDBY IMMEDIATE command failed.\n");

        return rv;
}

/*
 * Issue a READ LOG EXT command to the device.
 *
 * @port        pointer to the port structure.
 * @page        page number to fetch
 * @buffer      pointer to buffer
 * @buffer_dma  dma address corresponding to @buffer
 * @sectors     page length to fetch, in sectors
 *
 * return value
 *      @rv     return value from mtip_exec_internal_command()
 */
static int mtip_read_log_page(struct mtip_port *port, u8 page, u16 *buffer,
                                dma_addr_t buffer_dma, unsigned int sectors)
{
        struct host_to_dev_fis fis;

        memset(&fis, 0, sizeof(struct host_to_dev_fis));
        fis.type        = 0x27;
        fis.opts        = 1 << 7;
        fis.command     = ATA_CMD_READ_LOG_EXT;
        fis.sect_count  = sectors & 0xFF;
        fis.sect_cnt_ex = (sectors >> 8) & 0xFF;
        fis.lba_low     = page;
        fis.lba_mid     = 0;
        fis.device      = ATA_DEVICE_OBS;

        memset(buffer, 0, sectors * ATA_SECT_SIZE);

        return mtip_exec_internal_command(port,
                                        &fis,
                                        5,
                                        buffer_dma,
                                        sectors * ATA_SECT_SIZE,
                                        0,
                                        MTIP_INT_CMD_TIMEOUT_MS);
}

/*
 * Issue a SMART READ DATA command to the device.
 *
 * @port        pointer to the port structure.
 * @buffer      pointer to buffer
 * @buffer_dma  dma address corresponding to @buffer
 *
 * return value
 *      @rv     return value from mtip_exec_internal_command()
 */
static int mtip_get_smart_data(struct mtip_port *port, u8 *buffer,
                                        dma_addr_t buffer_dma)
{
        struct host_to_dev_fis fis;

        memset(&fis, 0, sizeof(struct host_to_dev_fis));
        fis.type        = 0x27;
        fis.opts        = 1 << 7;
        fis.command     = ATA_CMD_SMART;
        fis.features    = 0xD0;
        fis.sect_count  = 1;
        fis.lba_mid     = 0x4F;
        fis.lba_hi      = 0xC2;
        fis.device      = ATA_DEVICE_OBS;

        return mtip_exec_internal_command(port,
                                        &fis,
                                        5,
                                        buffer_dma,
                                        ATA_SECT_SIZE,
                                        0,
                                        15000);
}

/*
 * Get the value of a smart attribute
 *
 * @port        pointer to the port structure
 * @id          attribute number
 * @attrib      pointer to return attrib information corresponding to @id
 *
 * return value
 *      -EINVAL NULL buffer passed or unsupported attribute @id.
 *      -EPERM  Identify data not valid, SMART not supported or not enabled
 */
static int mtip_get_smart_attr(struct mtip_port *port, unsigned int id,
                                                struct smart_attr *attrib)
{
        int rv, i;
        struct smart_attr *pattr;

        if (!attrib)
                return -EINVAL;

        if (!port->identify_valid) {
                dev_warn(&port->dd->pdev->dev, "IDENTIFY DATA not valid\n");
                return -EPERM;
        }
        if (!(port->identify[82] & 0x1)) {
                dev_warn(&port->dd->pdev->dev, "SMART not supported\n");
                return -EPERM;
        }
        if (!(port->identify[85] & 0x1)) {
                dev_warn(&port->dd->pdev->dev, "SMART not enabled\n");
                return -EPERM;
        }

        memset(port->smart_buf, 0, ATA_SECT_SIZE);
        rv = mtip_get_smart_data(port, port->smart_buf, port->smart_buf_dma);
        if (rv) {
                dev_warn(&port->dd->pdev->dev, "Failed to ge SMART data\n");
                return rv;
        }

        pattr = (struct smart_attr *)(port->smart_buf + 2);
        for (i = 0; i < 29; i++, pattr++)
                if (pattr->attr_id == id) {
                        memcpy(attrib, pattr, sizeof(struct smart_attr));
                        break;
                }

        if (i == 29) {
                dev_warn(&port->dd->pdev->dev,
                        "Query for invalid SMART attribute ID\n");
                rv = -EINVAL;
        }

        return rv;
}

/*
 * Get the drive capacity.
 *
 * @dd      Pointer to the device data structure.
 * @sectors Pointer to the variable that will receive the sector count.
 *
 * return value
 *      1 Capacity was returned successfully.
 *      0 The identify information is invalid.
 */
static bool mtip_hw_get_capacity(struct driver_data *dd, sector_t *sectors)
{
        struct mtip_port *port = dd->port;
        u64 total, raw0, raw1, raw2, raw3;
        raw0 = port->identify[100];
        raw1 = port->identify[101];
        raw2 = port->identify[102];
        raw3 = port->identify[103];
        total = raw0 | raw1<<16 | raw2<<32 | raw3<<48;
        *sectors = total;
        return (bool) !!port->identify_valid;
}

/*
 * Display the identify command data.
 *
 * @port Pointer to the port data structure.
 *
 * return value
 *      None
 */
static void mtip_dump_identify(struct mtip_port *port)
{
        sector_t sectors;
        unsigned short revid;
        char cbuf[42];

        if (!port->identify_valid)
                return;

        strlcpy(cbuf, (char *)(port->identify+10), 21);
        dev_info(&port->dd->pdev->dev,
                "Serial No.: %s\n", cbuf);

        strlcpy(cbuf, (char *)(port->identify+23), 9);
        dev_info(&port->dd->pdev->dev,
                "Firmware Ver.: %s\n", cbuf);

        strlcpy(cbuf, (char *)(port->identify+27), 41);
        dev_info(&port->dd->pdev->dev, "Model: %s\n", cbuf);

        dev_info(&port->dd->pdev->dev, "Security: %04x %s\n",
                port->identify[128],
                port->identify[128] & 0x4 ? "(LOCKED)" : "");

        if (mtip_hw_get_capacity(port->dd, &sectors))
                dev_info(&port->dd->pdev->dev,
                        "Capacity: %llu sectors (%llu MB)\n",
                         (u64)sectors,
                         ((u64)sectors) * ATA_SECT_SIZE >> 20);

        pci_read_config_word(port->dd->pdev, PCI_REVISION_ID, &revid);
        switch (revid & 0xFF) {
        case 0x1:
                strlcpy(cbuf, "A0", 3);
                break;
        case 0x3:
                strlcpy(cbuf, "A2", 3);
                break;
        default:
                strlcpy(cbuf, "?", 2);
                break;
        }
        dev_info(&port->dd->pdev->dev,
                "Card Type: %s\n", cbuf);
}

/*
 * Map the commands scatter list into the command table.
 *
 * @command Pointer to the command.
 * @nents Number of scatter list entries.
 *
 * return value
 *      None
 */
static inline void fill_command_sg(struct driver_data *dd,
                                struct mtip_cmd *command,
                                int nents)
{
        int n;
        unsigned int dma_len;
        struct mtip_cmd_sg *command_sg;
        struct scatterlist *sg;

        command_sg = command->command + AHCI_CMD_TBL_HDR_SZ;

        for_each_sg(command->sg, sg, nents, n) {
                dma_len = sg_dma_len(sg);
                if (dma_len > 0x400000)
                        dev_err(&dd->pdev->dev,
                                "DMA segment length truncated\n");
                command_sg->info = cpu_to_le32((dma_len-1) & 0x3FFFFF);
                command_sg->dba =  cpu_to_le32(sg_dma_address(sg));
                command_sg->dba_upper =
                        cpu_to_le32((sg_dma_address(sg) >> 16) >> 16);
                command_sg++;
        }
}

/*
 * @brief Execute a drive command.
 *
 * return value 0 The command completed successfully.
 * return value -1 An error occurred while executing the command.
 */
static int exec_drive_task(struct mtip_port *port, u8 *command)
{
        struct host_to_dev_fis  fis;
        struct host_to_dev_fis *reply = (port->rxfis + RX_FIS_D2H_REG);
        unsigned int to;

        /* Build the FIS. */
        memset(&fis, 0, sizeof(struct host_to_dev_fis));
        fis.type        = 0x27;
        fis.opts        = 1 << 7;
        fis.command     = command[0];
        fis.features    = command[1];
        fis.sect_count  = command[2];
        fis.sector      = command[3];
        fis.cyl_low     = command[4];
        fis.cyl_hi      = command[5];
        fis.device      = command[6] & ~0x10; /* Clear the dev bit*/

        mtip_set_timeout(port->dd, &fis, &to, 0);

        dbg_printk(MTIP_DRV_NAME " %s: User Command: cmd %x, feat %x, nsect %x, sect %x, lcyl %x, hcyl %x, sel %x\n",
                __func__,
                command[0],
                command[1],
                command[2],
                command[3],
                command[4],
                command[5],
                command[6]);

        /* Execute the command. */
        if (mtip_exec_internal_command(port,
                                 &fis,
                                 5,
                                 0,
                                 0,
                                 0,
                                 to) < 0) {
                return -1;
        }

        command[0] = reply->command; /* Status*/
        command[1] = reply->features; /* Error*/
        command[4] = reply->cyl_low;
        command[5] = reply->cyl_hi;

        dbg_printk(MTIP_DRV_NAME " %s: Completion Status: stat %x, err %x , cyl_lo %x cyl_hi %x\n",
                __func__,
                command[0],
                command[1],
                command[4],
                command[5]);

        return 0;
}

/*
 * @brief Execute a drive command.
 *
 * @param port Pointer to the port data structure.
 * @param command Pointer to the user specified command parameters.
 * @param user_buffer Pointer to the user space buffer where read sector
 *                   data should be copied.
 *
 * return value 0 The command completed successfully.
 * return value -EFAULT An error occurred while copying the completion
 *                 data to the user space buffer.
 * return value -1 An error occurred while executing the command.
 */
static int exec_drive_command(struct mtip_port *port, u8 *command,
                                void __user *user_buffer)
{
        struct host_to_dev_fis  fis;
        struct host_to_dev_fis *reply;
        u8 *buf = NULL;
        dma_addr_t dma_addr = 0;
        int rv = 0, xfer_sz = command[3];
        unsigned int to;

        if (xfer_sz) {
                if (!user_buffer)
                        return -EFAULT;

                buf = dma_alloc_coherent(&port->dd->pdev->dev,
                                ATA_SECT_SIZE * xfer_sz,
                                &dma_addr,
                                GFP_KERNEL);
                if (!buf) {
                        dev_err(&port->dd->pdev->dev,
                                "Memory allocation failed (%d bytes)\n",
                                ATA_SECT_SIZE * xfer_sz);
                        return -ENOMEM;
                }
        }

        /* Build the FIS. */
        memset(&fis, 0, sizeof(struct host_to_dev_fis));
        fis.type        = 0x27;
        fis.opts        = 1 << 7;
        fis.command     = command[0];
        fis.features    = command[2];
        fis.sect_count  = command[3];
        if (fis.command == ATA_CMD_SMART) {
                fis.sector      = command[1];
                fis.cyl_low     = 0x4F;
                fis.cyl_hi      = 0xC2;
        }

        mtip_set_timeout(port->dd, &fis, &to, 0);

        if (xfer_sz)
                reply = (port->rxfis + RX_FIS_PIO_SETUP);
        else
                reply = (port->rxfis + RX_FIS_D2H_REG);

        dbg_printk(MTIP_DRV_NAME
                " %s: User Command: cmd %x, sect %x, "
                "feat %x, sectcnt %x\n",
                __func__,
                command[0],
                command[1],
                command[2],
                command[3]);

        /* Execute the command. */
        if (mtip_exec_internal_command(port,
                                &fis,
                                 5,
                                 (xfer_sz ? dma_addr : 0),
                                 (xfer_sz ? ATA_SECT_SIZE * xfer_sz : 0),
                                 0,
                                 to)
                                 < 0) {
                rv = -EFAULT;
                goto exit_drive_command;
        }

        /* Collect the completion status. */
        command[0] = reply->command; /* Status*/
        command[1] = reply->features; /* Error*/
        command[2] = reply->sect_count;

        dbg_printk(MTIP_DRV_NAME
                " %s: Completion Status: stat %x, "
                "err %x, nsect %x\n",
                __func__,
                command[0],
                command[1],
                command[2]);

        if (xfer_sz) {
                if (copy_to_user(user_buffer,
                                 buf,
                                 ATA_SECT_SIZE * command[3])) {
                        rv = -EFAULT;
                        goto exit_drive_command;
                }
        }
exit_drive_command:
        if (buf)
                dma_free_coherent(&port->dd->pdev->dev,
                                ATA_SECT_SIZE * xfer_sz, buf, dma_addr);
        return rv;
}

/*
 *  Indicates whether a command has a single sector payload.
 *
 *  @command passed to the device to perform the certain event.
 *  @features passed to the device to perform the certain event.
 *
 *  return value
 *      1       command is one that always has a single sector payload,
 *              regardless of the value in the Sector Count field.
 *      0       otherwise
 *
 */
static unsigned int implicit_sector(unsigned char command,
                                    unsigned char features)
{
        unsigned int rv = 0;

        /* list of commands that have an implicit sector count of 1 */
        switch (command) {
        case ATA_CMD_SEC_SET_PASS:
        case ATA_CMD_SEC_UNLOCK:
        case ATA_CMD_SEC_ERASE_PREP:
        case ATA_CMD_SEC_ERASE_UNIT:
        case ATA_CMD_SEC_FREEZE_LOCK:
        case ATA_CMD_SEC_DISABLE_PASS:
        case ATA_CMD_PMP_READ:
        case ATA_CMD_PMP_WRITE:
                rv = 1;
                break;
        case ATA_CMD_SET_MAX:
                if (features == ATA_SET_MAX_UNLOCK)
                        rv = 1;
                break;
        case ATA_CMD_SMART:
                if ((features == ATA_SMART_READ_VALUES) ||
                                (features == ATA_SMART_READ_THRESHOLDS))
                        rv = 1;
                break;
        case ATA_CMD_CONF_OVERLAY:
                if ((features == ATA_DCO_IDENTIFY) ||
                                (features == ATA_DCO_SET))
                        rv = 1;
                break;
        }
        return rv;
}

/*
 * Executes a taskfile
 * See ide_taskfile_ioctl() for derivation
 */
static int exec_drive_taskfile(struct driver_data *dd,
                               void __user *buf,
                               ide_task_request_t *req_task,
                               int outtotal)
{
        struct host_to_dev_fis  fis;
        struct host_to_dev_fis *reply;
        u8 *outbuf = NULL;
        u8 *inbuf = NULL;
        dma_addr_t outbuf_dma = 0;
        dma_addr_t inbuf_dma = 0;
        dma_addr_t dma_buffer = 0;
        int err = 0;
        unsigned int taskin = 0;
        unsigned int taskout = 0;
        u8 nsect = 0;
        unsigned int timeout;
        unsigned int force_single_sector;
        unsigned int transfer_size;
        unsigned long task_file_data;
        int intotal = outtotal + req_task->out_size;
        int erasemode = 0;

        taskout = req_task->out_size;
        taskin = req_task->in_size;
        /* 130560 = 512 * 0xFF*/
        if (taskin > 130560 || taskout > 130560)
                return -EINVAL;

        if (taskout) {
                outbuf = memdup_user(buf + outtotal, taskout);
                if (IS_ERR(outbuf))
                        return PTR_ERR(outbuf);

                outbuf_dma = dma_map_single(&dd->pdev->dev, outbuf,
                                            taskout, DMA_TO_DEVICE);
                if (dma_mapping_error(&dd->pdev->dev, outbuf_dma)) {
                        err = -ENOMEM;
                        goto abort;
                }
                dma_buffer = outbuf_dma;
        }

        if (taskin) {
                inbuf = memdup_user(buf + intotal, taskin);
                if (IS_ERR(inbuf)) {
                        err = PTR_ERR(inbuf);
                        inbuf = NULL;
                        goto abort;
                }
                inbuf_dma = dma_map_single(&dd->pdev->dev, inbuf,
                                           taskin, DMA_FROM_DEVICE);
                if (dma_mapping_error(&dd->pdev->dev, inbuf_dma)) {
                        err = -ENOMEM;
                        goto abort;
                }
                dma_buffer = inbuf_dma;
        }

        /* only supports PIO and non-data commands from this ioctl. */
        switch (req_task->data_phase) {
        case TASKFILE_OUT:
                nsect = taskout / ATA_SECT_SIZE;
                reply = (dd->port->rxfis + RX_FIS_PIO_SETUP);
                break;
        case TASKFILE_IN:
                reply = (dd->port->rxfis + RX_FIS_PIO_SETUP);
                break;
        case TASKFILE_NO_DATA:
                reply = (dd->port->rxfis + RX_FIS_D2H_REG);
                break;
        default:
                err = -EINVAL;
                goto abort;
        }

        /* Build the FIS. */
        memset(&fis, 0, sizeof(struct host_to_dev_fis));

        fis.type        = 0x27;
        fis.opts        = 1 << 7;
        fis.command     = req_task->io_ports[7];
        fis.features    = req_task->io_ports[1];
        fis.sect_count  = req_task->io_ports[2];
        fis.lba_low     = req_task->io_ports[3];
        fis.lba_mid     = req_task->io_ports[4];
        fis.lba_hi      = req_task->io_ports[5];
         /* Clear the dev bit*/
        fis.device      = req_task->io_ports[6] & ~0x10;

        if ((req_task->in_flags.all == 0) && (req_task->out_flags.all & 1)) {
                req_task->in_flags.all  =
                        IDE_TASKFILE_STD_IN_FLAGS |
                        (IDE_HOB_STD_IN_FLAGS << 8);
                fis.lba_low_ex          = req_task->hob_ports[3];
                fis.lba_mid_ex          = req_task->hob_ports[4];
                fis.lba_hi_ex           = req_task->hob_ports[5];
                fis.features_ex         = req_task->hob_ports[1];
                fis.sect_cnt_ex         = req_task->hob_ports[2];

        } else {
                req_task->in_flags.all = IDE_TASKFILE_STD_IN_FLAGS;
        }

        force_single_sector = implicit_sector(fis.command, fis.features);

        if ((taskin || taskout) && (!fis.sect_count)) {
                if (nsect)
                        fis.sect_count = nsect;
                else {
                        if (!force_single_sector) {
                                dev_warn(&dd->pdev->dev,
                                        "data movement but "
                                        "sect_count is 0\n");
                                err = -EINVAL;
                                goto abort;
                        }
                }
        }

        dbg_printk(MTIP_DRV_NAME
                " %s: cmd %x, feat %x, nsect %x,"
                " sect/lbal %x, lcyl/lbam %x, hcyl/lbah %x,"
                " head/dev %x\n",
                __func__,
                fis.command,
                fis.features,
                fis.sect_count,
                fis.lba_low,
                fis.lba_mid,
                fis.lba_hi,
                fis.device);

        /* check for erase mode support during secure erase.*/
        if ((fis.command == ATA_CMD_SEC_ERASE_UNIT) && outbuf &&
                                        (outbuf[0] & MTIP_SEC_ERASE_MODE)) {
                erasemode = 1;
        }

        mtip_set_timeout(dd, &fis, &timeout, erasemode);

        /* Determine the correct transfer size.*/
        if (force_single_sector)
                transfer_size = ATA_SECT_SIZE;
        else
                transfer_size = ATA_SECT_SIZE * fis.sect_count;

        /* Execute the command.*/
        if (mtip_exec_internal_command(dd->port,
                                 &fis,
                                 5,
                                 dma_buffer,
                                 transfer_size,
                                 0,
                                 timeout) < 0) {
                err = -EIO;
                goto abort;
        }

        task_file_data = readl(dd->port->mmio+PORT_TFDATA);

        if ((req_task->data_phase == TASKFILE_IN) && !(task_file_data & 1)) {
                reply = dd->port->rxfis + RX_FIS_PIO_SETUP;
                req_task->io_ports[7] = reply->control;
        } else {
                reply = dd->port->rxfis + RX_FIS_D2H_REG;
                req_task->io_ports[7] = reply->command;
        }

        /* reclaim the DMA buffers.*/
        if (inbuf_dma)
                dma_unmap_single(&dd->pdev->dev, inbuf_dma, taskin,
                                 DMA_FROM_DEVICE);
        if (outbuf_dma)
                dma_unmap_single(&dd->pdev->dev, outbuf_dma, taskout,
                                 DMA_TO_DEVICE);
        inbuf_dma  = 0;
        outbuf_dma = 0;

        /* return the ATA registers to the caller.*/
        req_task->io_ports[1] = reply->features;
        req_task->io_ports[2] = reply->sect_count;
        req_task->io_ports[3] = reply->lba_low;
        req_task->io_ports[4] = reply->lba_mid;
        req_task->io_ports[5] = reply->lba_hi;
        req_task->io_ports[6] = reply->device;

        if (req_task->out_flags.all & 1)  {

                req_task->hob_ports[3] = reply->lba_low_ex;
                req_task->hob_ports[4] = reply->lba_mid_ex;
                req_task->hob_ports[5] = reply->lba_hi_ex;
                req_task->hob_ports[1] = reply->features_ex;
                req_task->hob_ports[2] = reply->sect_cnt_ex;
        }
        dbg_printk(MTIP_DRV_NAME
                " %s: Completion: stat %x,"
                "err %x, sect_cnt %x, lbalo %x,"
                "lbamid %x, lbahi %x, dev %x\n",
                __func__,
                req_task->io_ports[7],
                req_task->io_ports[1],
                req_task->io_ports[2],
                req_task->io_ports[3],
                req_task->io_ports[4],
                req_task->io_ports[5],
                req_task->io_ports[6]);

        if (taskout) {
                if (copy_to_user(buf + outtotal, outbuf, taskout)) {
                        err = -EFAULT;
                        goto abort;
                }
        }
        if (taskin) {
                if (copy_to_user(buf + intotal, inbuf, taskin)) {
                        err = -EFAULT;
                        goto abort;
                }
        }
abort:
        if (inbuf_dma)
                dma_unmap_single(&dd->pdev->dev, inbuf_dma, taskin,
                                 DMA_FROM_DEVICE);
        if (outbuf_dma)
                dma_unmap_single(&dd->pdev->dev, outbuf_dma, taskout,
                                 DMA_TO_DEVICE);
        kfree(outbuf);
        kfree(inbuf);

        return err;
}

/*
 * Handle IOCTL calls from the Block Layer.
 *
 * This function is called by the Block Layer when it receives an IOCTL
 * command that it does not understand. If the IOCTL command is not supported
 * this function returns -ENOTTY.
 *
 * @dd  Pointer to the driver data structure.
 * @cmd IOCTL command passed from the Block Layer.
 * @arg IOCTL argument passed from the Block Layer.
 *
 * return value
 *      0       The IOCTL completed successfully.
 *      -ENOTTY The specified command is not supported.
 *      -EFAULT An error occurred copying data to a user space buffer.
 *      -EIO    An error occurred while executing the command.
 */
static int mtip_hw_ioctl(struct driver_data *dd, unsigned int cmd,
                         unsigned long arg)
{
        switch (cmd) {
        case HDIO_GET_IDENTITY:
        {
                if (copy_to_user((void __user *)arg, dd->port->identify,
                                                sizeof(u16) * ATA_ID_WORDS))
                        return -EFAULT;
                break;
        }
        case HDIO_DRIVE_CMD:
        {
                u8 drive_command[4];

                /* Copy the user command info to our buffer. */
                if (copy_from_user(drive_command,
                                         (void __user *) arg,
                                         sizeof(drive_command)))
                        return -EFAULT;

                /* Execute the drive command. */
                if (exec_drive_command(dd->port,
                                         drive_command,
                                         (void __user *) (arg+4)))
                        return -EIO;

                /* Copy the status back to the users buffer. */
                if (copy_to_user((void __user *) arg,
                                         drive_command,
                                         sizeof(drive_command)))
                        return -EFAULT;

                break;
        }
        case HDIO_DRIVE_TASK:
        {
                u8 drive_command[7];

                /* Copy the user command info to our buffer. */
                if (copy_from_user(drive_command,
                                         (void __user *) arg,
                                         sizeof(drive_command)))
                        return -EFAULT;

                /* Execute the drive command. */
                if (exec_drive_task(dd->port, drive_command))

                        return -EIO;

                /* Copy the status back to the users buffer. */
                if (copy_to_user((void __user *) arg,
                                         drive_command,
                                         sizeof(drive_command)))
                        return -EFAULT;

                break;
        }
        case HDIO_DRIVE_TASKFILE: {
                ide_task_request_t req_task;
                int ret, outtotal;

                if (copy_from_user(&req_task, (void __user *) arg,
                                        sizeof(req_task)))
                        return -EFAULT;

                outtotal = sizeof(req_task);

                ret = exec_drive_taskfile(dd, (void __user *) arg,
                                                &req_task, outtotal);

                if (copy_to_user((void __user *) arg, &req_task,
                                                        sizeof(req_task)))
                        return -EFAULT;

                return ret;
        }

        default:
                return -EINVAL;
        }
        return 0;
}

/*
 * Submit an IO to the hw
 *
 * This function is called by the block layer to issue an io
 * to the device. Upon completion, the callback function will
 * be called with the data parameter passed as the callback data.
 *
 * @dd       Pointer to the driver data structure.
 * @start    First sector to read.
 * @nsect    Number of sectors to read.
 * @tag      The tag of this read command.
 * @callback Pointer to the function that should be called
 *           when the read completes.
 * @data     Callback data passed to the callback function
 *           when the read completes.
 * @dir      Direction (read or write)
 *
 * return value
 *      None
 */
static void mtip_hw_submit_io(struct driver_data *dd, struct request *rq,
                              struct mtip_cmd *command,
                              struct blk_mq_hw_ctx *hctx)
{
        struct mtip_cmd_hdr *hdr =
                dd->port->command_list + sizeof(struct mtip_cmd_hdr) * rq->tag;
        struct host_to_dev_fis  *fis;
        struct mtip_port *port = dd->port;
        int dma_dir = rq_data_dir(rq) == READ ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
        u64 start = blk_rq_pos(rq);
        unsigned int nsect = blk_rq_sectors(rq);
        unsigned int nents;

        /* Map the scatter list for DMA access */
        nents = blk_rq_map_sg(hctx->queue, rq, command->sg);
        nents = dma_map_sg(&dd->pdev->dev, command->sg, nents, dma_dir);

        prefetch(&port->flags);

        command->scatter_ents = nents;

        /*
         * The number of retries for this command before it is
         * reported as a failure to the upper layers.
         */
        command->retries = MTIP_MAX_RETRIES;

        /* Fill out fis */
        fis = command->command;
        fis->type        = 0x27;
        fis->opts        = 1 << 7;
        if (dma_dir == DMA_FROM_DEVICE)
                fis->command = ATA_CMD_FPDMA_READ;
        else
                fis->command = ATA_CMD_FPDMA_WRITE;
        fis->lba_low     = start & 0xFF;
        fis->lba_mid     = (start >> 8) & 0xFF;
        fis->lba_hi      = (start >> 16) & 0xFF;
        fis->lba_low_ex  = (start >> 24) & 0xFF;
        fis->lba_mid_ex  = (start >> 32) & 0xFF;
        fis->lba_hi_ex   = (start >> 40) & 0xFF;
        fis->device      = 1 << 6;
        fis->features    = nsect & 0xFF;
        fis->features_ex = (nsect >> 8) & 0xFF;
        fis->sect_count  = ((rq->tag << 3) | (rq->tag >> 5));
        fis->sect_cnt_ex = 0;
        fis->control     = 0;
        fis->res2        = 0;
        fis->res3        = 0;
        fill_command_sg(dd, command, nents);

        if (unlikely(command->unaligned))
                fis->device |= 1 << 7;

        /* Populate the command header */
        hdr->ctba = cpu_to_le32(command->command_dma & 0xFFFFFFFF);
        if (test_bit(MTIP_PF_HOST_CAP_64, &dd->port->flags))
                hdr->ctbau = cpu_to_le32((command->command_dma >> 16) >> 16);
        hdr->opts = cpu_to_le32((nents << 16) | 5 | AHCI_CMD_PREFETCH);
        hdr->byte_count = 0;

        command->direction = dma_dir;

        /*
         * To prevent this command from being issued
         * if an internal command is in progress or error handling is active.
         */
        if (unlikely(port->flags & MTIP_PF_PAUSE_IO)) {
                set_bit(rq->tag, port->cmds_to_issue);
                set_bit(MTIP_PF_ISSUE_CMDS_BIT, &port->flags);
                return;
        }

        /* Issue the command to the hardware */
        mtip_issue_ncq_command(port, rq->tag);
}

/*
 * Sysfs status dump.
 *
 * @dev  Pointer to the device structure, passed by the kernrel.
 * @attr Pointer to the device_attribute structure passed by the kernel.
 * @buf  Pointer to the char buffer that will receive the stats info.
 *
 * return value
 *      The size, in bytes, of the data copied into buf.
 */
static ssize_t mtip_hw_show_status(struct device *dev,
                                struct device_attribute *attr,
                                char *buf)
{
        struct driver_data *dd = dev_to_disk(dev)->private_data;
        int size = 0;

        if (test_bit(MTIP_DDF_OVER_TEMP_BIT, &dd->dd_flag))
                size += sprintf(buf, "%s", "thermal_shutdown\n");
        else if (test_bit(MTIP_DDF_WRITE_PROTECT_BIT, &dd->dd_flag))
                size += sprintf(buf, "%s", "write_protect\n");
        else
                size += sprintf(buf, "%s", "online\n");

        return size;
}

static DEVICE_ATTR(status, 0444, mtip_hw_show_status, NULL);

static struct attribute *mtip_disk_attrs[] = {
        &dev_attr_status.attr,
        NULL,
};

static const struct attribute_group mtip_disk_attr_group = {
        .attrs = mtip_disk_attrs,
};

static const struct attribute_group *mtip_disk_attr_groups[] = {
        &mtip_disk_attr_group,
        NULL,
};

/* debugsfs entries */

static ssize_t show_device_status(struct device_driver *drv, char *buf)
{
        int size = 0;
        struct driver_data *dd, *tmp;
        unsigned long flags;
        char id_buf[42];
        u16 status = 0;

        spin_lock_irqsave(&dev_lock, flags);
        size += sprintf(&buf[size], "Devices Present:\n");
        list_for_each_entry_safe(dd, tmp, &online_list, online_list) {
                if (dd->pdev) {
                        if (dd->port &&
                            dd->port->identify &&
                            dd->port->identify_valid) {
                                strlcpy(id_buf,
                                        (char *) (dd->port->identify + 10), 21);
                                status = *(dd->port->identify + 141);
                        } else {
                                memset(id_buf, 0, 42);
                                status = 0;
                        }

                        if (dd->port &&
                            test_bit(MTIP_PF_REBUILD_BIT, &dd->port->flags)) {
                                size += sprintf(&buf[size],
                                        " device %s %s (ftl rebuild %d %%)\n",
                                        dev_name(&dd->pdev->dev),
                                        id_buf,
                                        status);
                        } else {
                                size += sprintf(&buf[size],
                                        " device %s %s\n",
                                        dev_name(&dd->pdev->dev),
                                        id_buf);
                        }
                }
        }

        size += sprintf(&buf[size], "Devices Being Removed:\n");
        list_for_each_entry_safe(dd, tmp, &removing_list, remove_list) {
                if (dd->pdev) {
                        if (dd->port &&
                            dd->port->identify &&
                            dd->port->identify_valid) {
                                strlcpy(id_buf,
                                        (char *) (dd->port->identify+10), 21);
                                status = *(dd->port->identify + 141);
                        } else {
                                memset(id_buf, 0, 42);
                                status = 0;
                        }

                        if (dd->port &&
                            test_bit(MTIP_PF_REBUILD_BIT, &dd->port->flags)) {
                                size += sprintf(&buf[size],
                                        " device %s %s (ftl rebuild %d %%)\n",
                                        dev_name(&dd->pdev->dev),
                                        id_buf,
                                        status);
                        } else {
                                size += sprintf(&buf[size],
                                        " device %s %s\n",
                                        dev_name(&dd->pdev->dev),
                                        id_buf);
                        }
                }
        }
        spin_unlock_irqrestore(&dev_lock, flags);

        return size;
}

static ssize_t mtip_hw_read_device_status(struct file *f, char __user *ubuf,
                                                size_t len, loff_t *offset)
{
        int size = *offset;
        char *buf;
        int rv = 0;

        if (!len || *offset)
                return 0;

        buf = kzalloc(MTIP_DFS_MAX_BUF_SIZE, GFP_KERNEL);
        if (!buf)
                return -ENOMEM;

        size += show_device_status(NULL, buf);

        *offset = size <= len ? size : len;
        size = copy_to_user(ubuf, buf, *offset);
        if (size)
                rv = -EFAULT;

        kfree(buf);
        return rv ? rv : *offset;
}

static ssize_t mtip_hw_read_registers(struct file *f, char __user *ubuf,
                                  size_t len, loff_t *offset)
{
        struct driver_data *dd =  (struct driver_data *)f->private_data;
        char *buf;
        u32 group_allocated;
        int size = *offset;
        int n, rv = 0;

        if (!len || size)
                return 0;

        buf = kzalloc(MTIP_DFS_MAX_BUF_SIZE, GFP_KERNEL);
        if (!buf)
                return -ENOMEM;

        size += sprintf(&buf[size], "H/ S ACTive      : [ 0x");

        for (n = dd->slot_groups-1; n >= 0; n--)
                size += sprintf(&buf[size], "%08X ",
                                         readl(dd->port->s_active[n]));

        size += sprintf(&buf[size], "]\n");
        size += sprintf(&buf[size], "H/ Command Issue : [ 0x");

        for (n = dd->slot_groups-1; n >= 0; n--)
                size += sprintf(&buf[size], "%08X ",
                                        readl(dd->port->cmd_issue[n]));

        size += sprintf(&buf[size], "]\n");
        size += sprintf(&buf[size], "H/ Completed     : [ 0x");

        for (n = dd->slot_groups-1; n >= 0; n--)
                size += sprintf(&buf[size], "%08X ",
                                readl(dd->port->completed[n]));

        size += sprintf(&buf[size], "]\n");
        size += sprintf(&buf[size], "H/ PORT IRQ STAT : [ 0x%08X ]\n",
                                readl(dd->port->mmio + PORT_IRQ_STAT));
        size += sprintf(&buf[size], "H/ HOST IRQ STAT : [ 0x%08X ]\n",
                                readl(dd->mmio + HOST_IRQ_STAT));
        size += sprintf(&buf[size], "\n");

        size += sprintf(&buf[size], "L/ Commands in Q : [ 0x");

        for (n = dd->slot_groups-1; n >= 0; n--) {
                if (sizeof(long) > sizeof(u32))
                        group_allocated =
                                dd->port->cmds_to_issue[n/2] >> (32*(n&1));
                else
                        group_allocated = dd->port->cmds_to_issue[n];
                size += sprintf(&buf[size], "%08X ", group_allocated);
        }
        size += sprintf(&buf[size], "]\n");

        *offset = size <= len ? size : len;
        size = copy_to_user(ubuf, buf, *offset);
        if (size)
                rv = -EFAULT;

        kfree(buf);
        return rv ? rv : *offset;
}

static ssize_t mtip_hw_read_flags(struct file *f, char __user *ubuf,
                                  size_t len, loff_t *offset)
{
        struct driver_data *dd =  (struct driver_data *)f->private_data;
        char *buf;
        int size = *offset;
        int rv = 0;

        if (!len || size)
                return 0;

        buf = kzalloc(MTIP_DFS_MAX_BUF_SIZE, GFP_KERNEL);
        if (!buf)
                return -ENOMEM;

        size += sprintf(&buf[size], "Flag-port : [ %08lX ]\n",
                                                        dd->port->flags);
        size += sprintf(&buf[size], "Flag-dd   : [ %08lX ]\n",
                                                        dd->dd_flag);

        *offset = size <= len ? size : len;
        size = copy_to_user(ubuf, buf, *offset);
        if (size)
                rv = -EFAULT;

        kfree(buf);
        return rv ? rv : *offset;
}

static const struct file_operations mtip_device_status_fops = {
        .owner  = THIS_MODULE,
        .open   = simple_open,
        .read   = mtip_hw_read_device_status,
        .llseek = no_llseek,
};

static const struct file_operations mtip_regs_fops = {
        .owner  = THIS_MODULE,
        .open   = simple_open,
        .read   = mtip_hw_read_registers,
        .llseek = no_llseek,
};

static const struct file_operations mtip_flags_fops = {
        .owner  = THIS_MODULE,
        .open   = simple_open,
        .read   = mtip_hw_read_flags,
        .llseek = no_llseek,
};

static int mtip_hw_debugfs_init(struct driver_data *dd)
{
        if (!dfs_parent)
                return -1;

        dd->dfs_node = debugfs_create_dir(dd->disk->disk_name, dfs_parent);
        if (IS_ERR_OR_NULL(dd->dfs_node)) {
                dev_warn(&dd->pdev->dev,
                        "Error creating node %s under debugfs\n",
                                                dd->disk->disk_name);
                dd->dfs_node = NULL;
                return -1;
        }

        debugfs_create_file("flags", 0444, dd->dfs_node, dd, &mtip_flags_fops);
        debugfs_create_file("registers", 0444, dd->dfs_node, dd,
                            &mtip_regs_fops);

        return 0;
}

static void mtip_hw_debugfs_exit(struct driver_data *dd)
{
        debugfs_remove_recursive(dd->dfs_node);
}

/*
 * Perform any init/resume time hardware setup
 *
 * @dd Pointer to the driver data structure.
 *
 * return value
 *      None
 */
static inline void hba_setup(struct driver_data *dd)
{
        u32 hwdata;
        hwdata = readl(dd->mmio + HOST_HSORG);

        /* interrupt bug workaround: use only 1 IS bit.*/
        writel(hwdata |
                HSORG_DISABLE_SLOTGRP_INTR |
                HSORG_DISABLE_SLOTGRP_PXIS,
                dd->mmio + HOST_HSORG);
}

static int mtip_device_unaligned_constrained(struct driver_data *dd)
{
        return (dd->pdev->device == P420M_DEVICE_ID ? 1 : 0);
}

/*
 * Detect the details of the product, and store anything needed
 * into the driver data structure.  This includes product type and
 * version and number of slot groups.
 *
 * @dd Pointer to the driver data structure.
 *
 * return value
 *      None
 */
static void mtip_detect_product(struct driver_data *dd)
{
        u32 hwdata;
        unsigned int rev, slotgroups;

        /*
         * HBA base + 0xFC [15:0] - vendor-specific hardware interface
         * info register:
         * [15:8] hardware/software interface rev#
         * [   3] asic-style interface
         * [ 2:0] number of slot groups, minus 1 (only valid for asic-style).
         */
        hwdata = readl(dd->mmio + HOST_HSORG);

        dd->product_type = MTIP_PRODUCT_UNKNOWN;
        dd->slot_groups = 1;

        if (hwdata & 0x8) {
                dd->product_type = MTIP_PRODUCT_ASICFPGA;
                rev = (hwdata & HSORG_HWREV) >> 8;
                slotgroups = (hwdata & HSORG_SLOTGROUPS) + 1;
                dev_info(&dd->pdev->dev,
                        "ASIC-FPGA design, HS rev 0x%x, "
                        "%i slot groups [%i slots]\n",
                         rev,
                         slotgroups,
                         slotgroups * 32);

                if (slotgroups > MTIP_MAX_SLOT_GROUPS) {
                        dev_warn(&dd->pdev->dev,
                                "Warning: driver only supports "
                                "%i slot groups.\n", MTIP_MAX_SLOT_GROUPS);
                        slotgroups = MTIP_MAX_SLOT_GROUPS;
                }
                dd->slot_groups = slotgroups;
                return;
        }

        dev_warn(&dd->pdev->dev, "Unrecognized product id\n");
}

/*
 * Blocking wait for FTL rebuild to complete
 *
 * @dd Pointer to the DRIVER_DATA structure.
 *
 * return value
 *      0       FTL rebuild completed successfully
 *      -EFAULT FTL rebuild error/timeout/interruption
 */
static int mtip_ftl_rebuild_poll(struct driver_data *dd)
{
        unsigned long timeout, cnt = 0, start;

        dev_warn(&dd->pdev->dev,
                "FTL rebuild in progress. Polling for completion.\n");

        start = jiffies;
        timeout = jiffies + msecs_to_jiffies(MTIP_FTL_REBUILD_TIMEOUT_MS);

        do {
                if (unlikely(test_bit(MTIP_DDF_REMOVE_PENDING_BIT,
                                &dd->dd_flag)))
                        return -EFAULT;
                if (mtip_check_surprise_removal(dd->pdev))
                        return -EFAULT;

                if (mtip_get_identify(dd->port, NULL) < 0)
                        return -EFAULT;

                if (*(dd->port->identify + MTIP_FTL_REBUILD_OFFSET) ==
                        MTIP_FTL_REBUILD_MAGIC) {
                        ssleep(1);
                        /* Print message every 3 minutes */
                        if (cnt++ >= 180) {
                                dev_warn(&dd->pdev->dev,
                                "FTL rebuild in progress (%d secs).\n",
                                jiffies_to_msecs(jiffies - start) / 1000);
                                cnt = 0;
                        }
                } else {
                        dev_warn(&dd->pdev->dev,
                                "FTL rebuild complete (%d secs).\n",
                        jiffies_to_msecs(jiffies - start) / 1000);
                        mtip_block_initialize(dd);
                        return 0;
                }
        } while (time_before(jiffies, timeout));

        /* Check for timeout */
        dev_err(&dd->pdev->dev,
                "Timed out waiting for FTL rebuild to complete (%d secs).\n",
                jiffies_to_msecs(jiffies - start) / 1000);
        return -EFAULT;
}

static void mtip_softirq_done_fn(struct request *rq)
{
        struct mtip_cmd *cmd = blk_mq_rq_to_pdu(rq);
        struct driver_data *dd = rq->q->queuedata;

        /* Unmap the DMA scatter list entries */
        dma_unmap_sg(&dd->pdev->dev, cmd->sg, cmd->scatter_ents,
                                                        cmd->direction);

        if (unlikely(cmd->unaligned))
                atomic_inc(&dd->port->cmd_slot_unal);

        blk_mq_end_request(rq, cmd->status);
}

static bool mtip_abort_cmd(struct request *req, void *data, bool reserved)
{
        struct mtip_cmd *cmd = blk_mq_rq_to_pdu(req);
        struct driver_data *dd = data;

        dbg_printk(MTIP_DRV_NAME " Aborting request, tag = %d\n", req->tag);

        clear_bit(req->tag, dd->port->cmds_to_issue);
        cmd->status = BLK_STS_IOERR;
        mtip_softirq_done_fn(req);
        return true;
}

static bool mtip_queue_cmd(struct request *req, void *data, bool reserved)
{
        struct driver_data *dd = data;

        set_bit(req->tag, dd->port->cmds_to_issue);
        blk_abort_request(req);
        return true;
}

/*
 * service thread to issue queued commands
 *
 * @data Pointer to the driver data structure.
 *
 * return value
 *      0
 */

static int mtip_service_thread(void *data)
{
        struct driver_data *dd = (struct driver_data *)data;
        unsigned long slot, slot_start, slot_wrap, to;
        unsigned int num_cmd_slots = dd->slot_groups * 32;
        struct mtip_port *port = dd->port;

        while (1) {
                if (kthread_should_stop() ||
                        test_bit(MTIP_PF_SVC_THD_STOP_BIT, &port->flags))
                        goto st_out;
                clear_bit(MTIP_PF_SVC_THD_ACTIVE_BIT, &port->flags);

                /*
                 * the condition is to check neither an internal command is
                 * is in progress nor error handling is active
                 */
                wait_event_interruptible(port->svc_wait, (port->flags) &&
                        (port->flags & MTIP_PF_SVC_THD_WORK));

                if (kthread_should_stop() ||
                        test_bit(MTIP_PF_SVC_THD_STOP_BIT, &port->flags))
                        goto st_out;

                if (unlikely(test_bit(MTIP_DDF_REMOVE_PENDING_BIT,
                                &dd->dd_flag)))
                        goto st_out;

                set_bit(MTIP_PF_SVC_THD_ACTIVE_BIT, &port->flags);

restart_eh:
                /* Demux bits: start with error handling */
                if (test_bit(MTIP_PF_EH_ACTIVE_BIT, &port->flags)) {
                        mtip_handle_tfe(dd);
                        clear_bit(MTIP_PF_EH_ACTIVE_BIT, &port->flags);
                }

                if (test_bit(MTIP_PF_EH_ACTIVE_BIT, &port->flags))
                        goto restart_eh;

                if (test_bit(MTIP_PF_TO_ACTIVE_BIT, &port->flags)) {
                        to = jiffies + msecs_to_jiffies(5000);

                        do {
                                mdelay(100);
                        } while (atomic_read(&dd->irq_workers_active) != 0 &&
                                time_before(jiffies, to));

                        if (atomic_read(&dd->irq_workers_active) != 0)
                                dev_warn(&dd->pdev->dev,
                                        "Completion workers still active!");

                        blk_mq_quiesce_queue(dd->queue);

                        blk_mq_tagset_busy_iter(&dd->tags, mtip_queue_cmd, dd);

                        set_bit(MTIP_PF_ISSUE_CMDS_BIT, &dd->port->flags);

                        if (mtip_device_reset(dd))
                                blk_mq_tagset_busy_iter(&dd->tags,
                                                        mtip_abort_cmd, dd);

                        clear_bit(MTIP_PF_TO_ACTIVE_BIT, &dd->port->flags);

                        blk_mq_unquiesce_queue(dd->queue);
                }

                if (test_bit(MTIP_PF_ISSUE_CMDS_BIT, &port->flags)) {
                        slot = 1;
                        /* used to restrict the loop to one iteration */
                        slot_start = num_cmd_slots;
                        slot_wrap = 0;
                        while (1) {
                                slot = find_next_bit(port->cmds_to_issue,
                                                num_cmd_slots, slot);
                                if (slot_wrap == 1) {
                                        if ((slot_start >= slot) ||
                                                (slot >= num_cmd_slots))
                                                break;
                                }
                                if (unlikely(slot_start == num_cmd_slots))
                                        slot_start = slot;

                                if (unlikely(slot == num_cmd_slots)) {
                                        slot = 1;
                                        slot_wrap = 1;
                                        continue;
                                }

                                /* Issue the command to the hardware */
                                mtip_issue_ncq_command(port, slot);

                                clear_bit(slot, port->cmds_to_issue);
                        }

                        clear_bit(MTIP_PF_ISSUE_CMDS_BIT, &port->flags);
                }

                if (test_bit(MTIP_PF_REBUILD_BIT, &port->flags)) {
                        if (mtip_ftl_rebuild_poll(dd) == 0)
                                clear_bit(MTIP_PF_REBUILD_BIT, &port->flags);
                }
        }

st_out:
        return 0;
}

/*
 * DMA region teardown
 *
 * @dd Pointer to driver_data structure
 *
 * return value
 *      None
 */
static void mtip_dma_free(struct driver_data *dd)
{
        struct mtip_port *port = dd->port;

        if (port->block1)
                dma_free_coherent(&dd->pdev->dev, BLOCK_DMA_ALLOC_SZ,
                                        port->block1, port->block1_dma);

        if (port->command_list) {
                dma_free_coherent(&dd->pdev->dev, AHCI_CMD_TBL_SZ,
                                port->command_list, port->command_list_dma);
        }
}

/*
 * DMA region setup
 *
 * @dd Pointer to driver_data structure
 *
 * return value
 *      -ENOMEM Not enough free DMA region space to initialize driver
 */
static int mtip_dma_alloc(struct driver_data *dd)
{
        struct mtip_port *port = dd->port;

        /* Allocate dma memory for RX Fis, Identify, and Sector Bufffer */
        port->block1 =
                dma_alloc_coherent(&dd->pdev->dev, BLOCK_DMA_ALLOC_SZ,
                                        &port->block1_dma, GFP_KERNEL);
        if (!port->block1)
                return -ENOMEM;

        /* Allocate dma memory for command list */
        port->command_list =
                dma_alloc_coherent(&dd->pdev->dev, AHCI_CMD_TBL_SZ,
                                        &port->command_list_dma, GFP_KERNEL);
        if (!port->command_list) {
                dma_free_coherent(&dd->pdev->dev, BLOCK_DMA_ALLOC_SZ,
                                        port->block1, port->block1_dma);
                port->block1 = NULL;
                port->block1_dma = 0;
                return -ENOMEM;
        }

        /* Setup all pointers into first DMA region */
        port->rxfis         = port->block1 + AHCI_RX_FIS_OFFSET;
        port->rxfis_dma     = port->block1_dma + AHCI_RX_FIS_OFFSET;
        port->identify      = port->block1 + AHCI_IDFY_OFFSET;
        port->identify_dma  = port->block1_dma + AHCI_IDFY_OFFSET;
        port->log_buf       = port->block1 + AHCI_SECTBUF_OFFSET;
        port->log_buf_dma   = port->block1_dma + AHCI_SECTBUF_OFFSET;
        port->smart_buf     = port->block1 + AHCI_SMARTBUF_OFFSET;
        port->smart_buf_dma = port->block1_dma + AHCI_SMARTBUF_OFFSET;

        return 0;
}

static int mtip_hw_get_identify(struct driver_data *dd)
{
        struct smart_attr attr242;
        unsigned char *buf;
        int rv;

        if (mtip_get_identify(dd->port, NULL) < 0)
                return -EFAULT;

        if (*(dd->port->identify + MTIP_FTL_REBUILD_OFFSET) ==
                MTIP_FTL_REBUILD_MAGIC) {
                set_bit(MTIP_PF_REBUILD_BIT, &dd->port->flags);
                return MTIP_FTL_REBUILD_MAGIC;
        }
        mtip_dump_identify(dd->port);

        /* check write protect, over temp and rebuild statuses */
        rv = mtip_read_log_page(dd->port, ATA_LOG_SATA_NCQ,
                                dd->port->log_buf,
                                dd->port->log_buf_dma, 1);
        if (rv) {
                dev_warn(&dd->pdev->dev,
                        "Error in READ LOG EXT (10h) command\n");
                /* non-critical error, don't fail the load */
        } else {
                buf = (unsigned char *)dd->port->log_buf;
                if (buf[259] & 0x1) {
                        dev_info(&dd->pdev->dev,
                                "Write protect bit is set.\n");
                        set_bit(MTIP_DDF_WRITE_PROTECT_BIT, &dd->dd_flag);
                }
                if (buf[288] == 0xF7) {
                        dev_info(&dd->pdev->dev,
                                "Exceeded Tmax, drive in thermal shutdown.\n");
                        set_bit(MTIP_DDF_OVER_TEMP_BIT, &dd->dd_flag);
                }
                if (buf[288] == 0xBF) {
                        dev_info(&dd->pdev->dev,
                                "Drive indicates rebuild has failed.\n");
                        set_bit(MTIP_DDF_REBUILD_FAILED_BIT, &dd->dd_flag);
                }
        }

        /* get write protect progess */
        memset(&attr242, 0, sizeof(struct smart_attr));
        if (mtip_get_smart_attr(dd->port, 242, &attr242))
                dev_warn(&dd->pdev->dev,
                                "Unable to check write protect progress\n");
        else
                dev_info(&dd->pdev->dev,
                                "Write protect progress: %u%% (%u blocks)\n",
                                attr242.cur, le32_to_cpu(attr242.data));

        return rv;
}

/*
 * Called once for each card.
 *
 * @dd Pointer to the driver data structure.
 *
 * return value
 *      0 on success, else an error code.
 */
static int mtip_hw_init(struct driver_data *dd)
{
        int i;
        int rv;
        unsigned long timeout, timetaken;

        dd->mmio = pcim_iomap_table(dd->pdev)[MTIP_ABAR];

        mtip_detect_product(dd);
        if (dd->product_type == MTIP_PRODUCT_UNKNOWN) {
                rv = -EIO;
                goto out1;
        }

        hba_setup(dd);

        dd->port = kzalloc_node(sizeof(struct mtip_port), GFP_KERNEL,
                                dd->numa_node);
        if (!dd->port)
                return -ENOMEM;

        /* Continue workqueue setup */
        for (i = 0; i < MTIP_MAX_SLOT_GROUPS; i++)
                dd->work[i].port = dd->port;

        /* Enable unaligned IO constraints for some devices */
        if (mtip_device_unaligned_constrained(dd))
                dd->unal_qdepth = MTIP_MAX_UNALIGNED_SLOTS;
        else
                dd->unal_qdepth = 0;

        atomic_set(&dd->port->cmd_slot_unal, dd->unal_qdepth);

        /* Spinlock to prevent concurrent issue */
        for (i = 0; i < MTIP_MAX_SLOT_GROUPS; i++)
                spin_lock_init(&dd->port->cmd_issue_lock[i]);

        /* Set the port mmio base address. */
        dd->port->mmio  = dd->mmio + PORT_OFFSET;
        dd->port->dd    = dd;

        /* DMA allocations */
        rv = mtip_dma_alloc(dd);
        if (rv < 0)
                goto out1;

        /* Setup the pointers to the extended s_active and CI registers. */
        for (i = 0; i < dd->slot_groups; i++) {
                dd->port->s_active[i] =
                        dd->port->mmio + i*0x80 + PORT_SCR_ACT;
                dd->port->cmd_issue[i] =
                        dd->port->mmio + i*0x80 + PORT_COMMAND_ISSUE;
                dd->port->completed[i] =
                        dd->port->mmio + i*0x80 + PORT_SDBV;
        }

        timetaken = jiffies;
        timeout = jiffies + msecs_to_jiffies(30000);
        while (((readl(dd->port->mmio + PORT_SCR_STAT) & 0x0F) != 0x03) &&
                 time_before(jiffies, timeout)) {
                mdelay(100);
        }
        if (unlikely(mtip_check_surprise_removal(dd->pdev))) {
                timetaken = jiffies - timetaken;
                dev_warn(&dd->pdev->dev,
                        "Surprise removal detected at %u ms\n",
                        jiffies_to_msecs(timetaken));
                rv = -ENODEV;
                goto out2 ;
        }
        if (unlikely(test_bit(MTIP_DDF_REMOVE_PENDING_BIT, &dd->dd_flag))) {
                timetaken = jiffies - timetaken;
                dev_warn(&dd->pdev->dev,
                        "Removal detected at %u ms\n",
                        jiffies_to_msecs(timetaken));
                rv = -EFAULT;
                goto out2;
        }

        /* Conditionally reset the HBA. */
        if (!(readl(dd->mmio + HOST_CAP) & HOST_CAP_NZDMA)) {
                if (mtip_hba_reset(dd) < 0) {
                        dev_err(&dd->pdev->dev,
                                "Card did not reset within timeout\n");
                        rv = -EIO;
                        goto out2;
                }
        } else {
                /* Clear any pending interrupts on the HBA */
                writel(readl(dd->mmio + HOST_IRQ_STAT),
                        dd->mmio + HOST_IRQ_STAT);
        }

        mtip_init_port(dd->port);
        mtip_start_port(dd->port);

        /* Setup the ISR and enable interrupts. */
        rv = request_irq(dd->pdev->irq, mtip_irq_handler, IRQF_SHARED,
                         dev_driver_string(&dd->pdev->dev), dd);
        if (rv) {
                dev_err(&dd->pdev->dev,
                        "Unable to allocate IRQ %d\n", dd->pdev->irq);
                goto out2;
        }
        irq_set_affinity_hint(dd->pdev->irq, get_cpu_mask(dd->isr_binding));

        /* Enable interrupts on the HBA. */
        writel(readl(dd->mmio + HOST_CTL) | HOST_IRQ_EN,
                                        dd->mmio + HOST_CTL);

        init_waitqueue_head(&dd->port->svc_wait);

        if (test_bit(MTIP_DDF_REMOVE_PENDING_BIT, &dd->dd_flag)) {
                rv = -EFAULT;
                goto out3;
        }

        return rv;

out3:
        /* Disable interrupts on the HBA. */
        writel(readl(dd->mmio + HOST_CTL) & ~HOST_IRQ_EN,
                        dd->mmio + HOST_CTL);

        /* Release the IRQ. */
        irq_set_affinity_hint(dd->pdev->irq, NULL);
        free_irq(dd->pdev->irq, dd);

out2:
        mtip_deinit_port(dd->port);
        mtip_dma_free(dd);

out1:
        /* Free the memory allocated for the for structure. */
        kfree(dd->port);

        return rv;
}

static int mtip_standby_drive(struct driver_data *dd)
{
        int rv = 0;

        if (dd->sr || !dd->port)
                return -ENODEV;
        /*
         * Send standby immediate (E0h) to the drive so that it
         * saves its state.
         */
        if (!test_bit(MTIP_PF_REBUILD_BIT, &dd->port->flags) &&
            !test_bit(MTIP_DDF_REBUILD_FAILED_BIT, &dd->dd_flag) &&
            !test_bit(MTIP_DDF_SEC_LOCK_BIT, &dd->dd_flag)) {
                rv = mtip_standby_immediate(dd->port);
                if (rv)
                        dev_warn(&dd->pdev->dev,
                                "STANDBY IMMEDIATE failed\n");
        }
        return rv;
}

/*
 * Called to deinitialize an interface.
 *
 * @dd Pointer to the driver data structure.
 *
 * return value
 *      0
 */
static int mtip_hw_exit(struct driver_data *dd)