/*
   * Driver for sTec s1120 PCIe SSDs. sTec was acquired in 2013 by HGST and HGST
   * was acquired by Western Digital in 2012.

   *

   * Copyright 2012 sTec, Inc.
   * Copyright (c) 2017 Western Digital Corporation or its affiliates.
   *
   * This file is part of the Linux kernel, and is made available under
   * the terms of the GNU General Public License version 2.

   */
  
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/pci.h>
  #include <linux/slab.h>
  #include <linux/spinlock.h>
  #include <linux/blkdev.h>

  #include <linux/blk-mq.h>

  #include <linux/sched.h>
  #include <linux/interrupt.h>
  #include <linux/compiler.h>
  #include <linux/workqueue.h>

  #include <linux/delay.h>
  #include <linux/time.h>
  #include <linux/hdreg.h>
  #include <linux/dma-mapping.h>
  #include <linux/completion.h>
  #include <linux/scatterlist.h>
  #include <linux/version.h>
  #include <linux/err.h>

  #include <linux/aer.h>

  #include <linux/wait.h>

  #include <linux/stringify.h>

  #include <linux/slab_def.h>

  #include <scsi/scsi.h>

  #include <scsi/sg.h>
  #include <linux/io.h>
  #include <linux/uaccess.h>

  #include <asm/unaligned.h>

  
  #include "skd_s1120.h"
  
  static int skd_dbg_level;
  static int skd_isr_comp_limit = 4;

  #define SKD_ASSERT(expr) \
  	do { \
  		if (unlikely(!(expr))) { \
  			pr_err("Assertion failed! %s,%s,%s,line=%d
  ",	\
  			       # expr, __FILE__, __func__, __LINE__); \
  		} \
  	} while (0)

  #define DRV_NAME "skd"

  #define PFX DRV_NAME ": "

  MODULE_LICENSE("GPL");

  MODULE_DESCRIPTION("STEC s1120 PCIe SSD block driver");

  
  #define PCI_VENDOR_ID_STEC      0x1B39
  #define PCI_DEVICE_ID_S1120     0x0001
  
  #define SKD_FUA_NV		(1 << 1)
  #define SKD_MINORS_PER_DEVICE   16
  
  #define SKD_MAX_QUEUE_DEPTH     200u
  
  #define SKD_PAUSE_TIMEOUT       (5 * 1000)
  
  #define SKD_N_FITMSG_BYTES      (512u)

  #define SKD_MAX_REQ_PER_MSG	14

  #define SKD_N_SPECIAL_FITMSG_BYTES      (128u)
  
  /* SG elements are 32 bytes, so we can make this 4096 and still be under the
   * 128KB limit.  That allows 4096*4K = 16M xfer size
   */
  #define SKD_N_SG_PER_REQ_DEFAULT 256u

  
  #define SKD_N_COMPLETION_ENTRY  256u
  #define SKD_N_READ_CAP_BYTES    (8u)
  
  #define SKD_N_INTERNAL_BYTES    (512u)

  #define SKD_SKCOMP_SIZE							\
  	((sizeof(struct fit_completion_entry_v1) +			\
  	  sizeof(struct fit_comp_error_info)) * SKD_N_COMPLETION_ENTRY)

  /* 5 bits of uniqifier, 0xF800 */

  #define SKD_ID_TABLE_MASK       (3u << 8u)
  #define  SKD_ID_RW_REQUEST      (0u << 8u)
  #define  SKD_ID_INTERNAL        (1u << 8u)

  #define  SKD_ID_FIT_MSG         (3u << 8u)
  #define SKD_ID_SLOT_MASK        0x00FFu
  #define SKD_ID_SLOT_AND_TABLE_MASK 0x03FFu

  #define SKD_N_MAX_SECTORS 2048u
  
  #define SKD_MAX_RETRIES 2u
  
  #define SKD_TIMER_SECONDS(seconds) (seconds)
  #define SKD_TIMER_MINUTES(minutes) ((minutes) * (60))
  
  #define INQ_STD_NBYTES 36

  
  enum skd_drvr_state {
  	SKD_DRVR_STATE_LOAD,
  	SKD_DRVR_STATE_IDLE,
  	SKD_DRVR_STATE_BUSY,
  	SKD_DRVR_STATE_STARTING,
  	SKD_DRVR_STATE_ONLINE,
  	SKD_DRVR_STATE_PAUSING,
  	SKD_DRVR_STATE_PAUSED,

  	SKD_DRVR_STATE_RESTARTING,
  	SKD_DRVR_STATE_RESUMING,
  	SKD_DRVR_STATE_STOPPING,
  	SKD_DRVR_STATE_FAULT,
  	SKD_DRVR_STATE_DISAPPEARED,
  	SKD_DRVR_STATE_PROTOCOL_MISMATCH,
  	SKD_DRVR_STATE_BUSY_ERASE,
  	SKD_DRVR_STATE_BUSY_SANITIZE,
  	SKD_DRVR_STATE_BUSY_IMMINENT,
  	SKD_DRVR_STATE_WAIT_BOOT,
  	SKD_DRVR_STATE_SYNCING,
  };
  
  #define SKD_WAIT_BOOT_TIMO      SKD_TIMER_SECONDS(90u)
  #define SKD_STARTING_TIMO       SKD_TIMER_SECONDS(8u)
  #define SKD_RESTARTING_TIMO     SKD_TIMER_MINUTES(4u)

  #define SKD_BUSY_TIMO           SKD_TIMER_MINUTES(20u)
  #define SKD_STARTED_BUSY_TIMO   SKD_TIMER_SECONDS(60u)
  #define SKD_START_WAIT_SECONDS  90u
  
  enum skd_req_state {
  	SKD_REQ_STATE_IDLE,
  	SKD_REQ_STATE_SETUP,
  	SKD_REQ_STATE_BUSY,
  	SKD_REQ_STATE_COMPLETED,
  	SKD_REQ_STATE_TIMEOUT,

  };

  enum skd_check_status_action {
  	SKD_CHECK_STATUS_REPORT_GOOD,
  	SKD_CHECK_STATUS_REPORT_SMART_ALERT,
  	SKD_CHECK_STATUS_REQUEUE_REQUEST,
  	SKD_CHECK_STATUS_REPORT_ERROR,
  	SKD_CHECK_STATUS_BUSY_IMMINENT,
  };

  struct skd_msg_buf {
  	struct fit_msg_hdr	fmh;
  	struct skd_scsi_request	scsi[SKD_MAX_REQ_PER_MSG];
  };

  struct skd_fitmsg_context {

  	u32 id;

  
  	u32 length;

  	struct skd_msg_buf *msg_buf;

  	dma_addr_t mb_dma_address;
  };
  
  struct skd_request_context {
  	enum skd_req_state state;

  	u16 id;
  	u32 fitmsg_id;

  	u8 flush_cmd;

  	enum dma_data_direction data_dir;

  	struct scatterlist *sg;
  	u32 n_sg;
  	u32 sg_byte_count;
  
  	struct fit_sg_descriptor *sksg_list;
  	dma_addr_t sksg_dma_address;
  
  	struct fit_completion_entry_v1 completion;
  
  	struct fit_comp_error_info err_info;

  	blk_status_t status;

  };

  
  struct skd_special_context {
  	struct skd_request_context req;

  	void *data_buf;
  	dma_addr_t db_dma_address;

  	struct skd_msg_buf *msg_buf;

  	dma_addr_t mb_dma_address;
  };

  typedef enum skd_irq_type {
  	SKD_IRQ_LEGACY,
  	SKD_IRQ_MSI,
  	SKD_IRQ_MSIX
  } skd_irq_type_t;
  
  #define SKD_MAX_BARS                    2
  
  struct skd_device {

  	void __iomem *mem_map[SKD_MAX_BARS];

  	resource_size_t mem_phys[SKD_MAX_BARS];
  	u32 mem_size[SKD_MAX_BARS];

  	struct skd_msix_entry *msix_entries;
  
  	struct pci_dev *pdev;
  	int pcie_error_reporting_is_enabled;
  
  	spinlock_t lock;
  	struct gendisk *disk;

  	struct blk_mq_tag_set tag_set;

  	struct request_queue *queue;

  	struct skd_fitmsg_context *skmsg;

  	struct device *class_dev;
  	int gendisk_on;
  	int sync_done;

  	u32 devno;
  	u32 major;

  	char isr_name[30];
  
  	enum skd_drvr_state state;
  	u32 drive_state;

  	u32 cur_max_queue_depth;
  	u32 queue_low_water_mark;
  	u32 dev_max_queue_depth;
  
  	u32 num_fitmsg_context;
  	u32 num_req_context;

  	struct skd_fitmsg_context *skmsg_table;

  	struct skd_special_context internal_skspcl;
  	u32 read_cap_blocksize;
  	u32 read_cap_last_lba;
  	int read_cap_is_valid;
  	int inquiry_is_valid;
  	u8 inq_serial_num[13];  /*12 chars plus null term */

  
  	u8 skcomp_cycle;
  	u32 skcomp_ix;

  	struct kmem_cache *msgbuf_cache;
  	struct kmem_cache *sglist_cache;
  	struct kmem_cache *databuf_cache;

  	struct fit_completion_entry_v1 *skcomp_table;
  	struct fit_comp_error_info *skerr_table;
  	dma_addr_t cq_dma_address;
  
  	wait_queue_head_t waitq;
  
  	struct timer_list timer;
  	u32 timer_countdown;
  	u32 timer_substate;

  	int sgs_per_request;
  	u32 last_mtd;
  
  	u32 proto_ver;
  
  	int dbg_level;
  	u32 connect_time_stamp;
  	int connect_retries;
  #define SKD_MAX_CONNECT_RETRIES 16
  	u32 drive_jiffies;
  
  	u32 timo_slot;

  	struct work_struct start_queue;

  	struct work_struct completion_worker;

  };
  
  #define SKD_WRITEL(DEV, VAL, OFF) skd_reg_write32(DEV, VAL, OFF)
  #define SKD_READL(DEV, OFF)      skd_reg_read32(DEV, OFF)
  #define SKD_WRITEQ(DEV, VAL, OFF) skd_reg_write64(DEV, VAL, OFF)
  
  static inline u32 skd_reg_read32(struct skd_device *skdev, u32 offset)
  {

  	u32 val = readl(skdev->mem_map[1] + offset);

  	if (unlikely(skdev->dbg_level >= 2))

  		dev_dbg(&skdev->pdev->dev, "offset %x = %x
  ", offset, val);

  	return val;

  }
  
  static inline void skd_reg_write32(struct skd_device *skdev, u32 val,
  				   u32 offset)
  {

  	writel(val, skdev->mem_map[1] + offset);
  	if (unlikely(skdev->dbg_level >= 2))

  		dev_dbg(&skdev->pdev->dev, "offset %x = %x
  ", offset, val);

  }
  
  static inline void skd_reg_write64(struct skd_device *skdev, u64 val,
  				   u32 offset)
  {

  	writeq(val, skdev->mem_map[1] + offset);
  	if (unlikely(skdev->dbg_level >= 2))

  		dev_dbg(&skdev->pdev->dev, "offset %x = %016llx
  ", offset,
  			val);

  }

  #define SKD_IRQ_DEFAULT SKD_IRQ_MSIX

  static int skd_isr_type = SKD_IRQ_DEFAULT;
  
  module_param(skd_isr_type, int, 0444);
  MODULE_PARM_DESC(skd_isr_type, "Interrupt type capability."
  		 " (0==legacy, 1==MSI, 2==MSI-X, default==1)");
  
  #define SKD_MAX_REQ_PER_MSG_DEFAULT 1
  static int skd_max_req_per_msg = SKD_MAX_REQ_PER_MSG_DEFAULT;
  
  module_param(skd_max_req_per_msg, int, 0444);
  MODULE_PARM_DESC(skd_max_req_per_msg,
  		 "Maximum SCSI requests packed in a single message."

  		 " (1-" __stringify(SKD_MAX_REQ_PER_MSG) ", default==1)");

  
  #define SKD_MAX_QUEUE_DEPTH_DEFAULT 64
  #define SKD_MAX_QUEUE_DEPTH_DEFAULT_STR "64"
  static int skd_max_queue_depth = SKD_MAX_QUEUE_DEPTH_DEFAULT;
  
  module_param(skd_max_queue_depth, int, 0444);
  MODULE_PARM_DESC(skd_max_queue_depth,
  		 "Maximum SCSI requests issued to s1120."
  		 " (1-200, default==" SKD_MAX_QUEUE_DEPTH_DEFAULT_STR ")");
  
  static int skd_sgs_per_request = SKD_N_SG_PER_REQ_DEFAULT;
  module_param(skd_sgs_per_request, int, 0444);
  MODULE_PARM_DESC(skd_sgs_per_request,
  		 "Maximum SG elements per block request."
  		 " (1-4096, default==256)");

  static int skd_max_pass_thru = 1;

  module_param(skd_max_pass_thru, int, 0444);
  MODULE_PARM_DESC(skd_max_pass_thru,

  		 "Maximum SCSI pass-thru at a time. IGNORED");

  
  module_param(skd_dbg_level, int, 0444);
  MODULE_PARM_DESC(skd_dbg_level, "s1120 debug level (0,1,2)");
  
  module_param(skd_isr_comp_limit, int, 0444);
  MODULE_PARM_DESC(skd_isr_comp_limit, "s1120 isr comp limit (0=none) default=4");

  /* Major device number dynamically assigned. */
  static u32 skd_major;

  static void skd_destruct(struct skd_device *skdev);
  static const struct block_device_operations skd_blockdev_ops;
  static void skd_send_fitmsg(struct skd_device *skdev,
  			    struct skd_fitmsg_context *skmsg);
  static void skd_send_special_fitmsg(struct skd_device *skdev,
  				    struct skd_special_context *skspcl);

  static bool skd_preop_sg_list(struct skd_device *skdev,

  			     struct skd_request_context *skreq);
  static void skd_postop_sg_list(struct skd_device *skdev,
  			       struct skd_request_context *skreq);
  
  static void skd_restart_device(struct skd_device *skdev);
  static int skd_quiesce_dev(struct skd_device *skdev);
  static int skd_unquiesce_dev(struct skd_device *skdev);

  static void skd_disable_interrupts(struct skd_device *skdev);
  static void skd_isr_fwstate(struct skd_device *skdev);

  static void skd_recover_requests(struct skd_device *skdev);

  static void skd_soft_reset(struct skd_device *skdev);

  const char *skd_drive_state_to_str(int state);
  const char *skd_skdev_state_to_str(enum skd_drvr_state state);
  static void skd_log_skdev(struct skd_device *skdev, const char *event);

  static void skd_log_skreq(struct skd_device *skdev,
  			  struct skd_request_context *skreq, const char *event);

  /*
   *****************************************************************************
   * READ/WRITE REQUESTS
   *****************************************************************************
   */

  static void skd_inc_in_flight(struct request *rq, void *data, bool reserved)
  {
  	int *count = data;
  
  	count++;
  }
  
  static int skd_in_flight(struct skd_device *skdev)
  {
  	int count = 0;
  
  	blk_mq_tagset_busy_iter(&skdev->tag_set, skd_inc_in_flight, &count);
  
  	return count;
  }

  static void
  skd_prep_rw_cdb(struct skd_scsi_request *scsi_req,
  		int data_dir, unsigned lba,
  		unsigned count)
  {
  	if (data_dir == READ)

  		scsi_req->cdb[0] = READ_10;

  	else

  		scsi_req->cdb[0] = WRITE_10;

  
  	scsi_req->cdb[1] = 0;
  	scsi_req->cdb[2] = (lba & 0xff000000) >> 24;
  	scsi_req->cdb[3] = (lba & 0xff0000) >> 16;
  	scsi_req->cdb[4] = (lba & 0xff00) >> 8;
  	scsi_req->cdb[5] = (lba & 0xff);
  	scsi_req->cdb[6] = 0;
  	scsi_req->cdb[7] = (count & 0xff00) >> 8;
  	scsi_req->cdb[8] = count & 0xff;
  	scsi_req->cdb[9] = 0;
  }
  
  static void
  skd_prep_zerosize_flush_cdb(struct skd_scsi_request *scsi_req,

  			    struct skd_request_context *skreq)

  {
  	skreq->flush_cmd = 1;

  	scsi_req->cdb[0] = SYNCHRONIZE_CACHE;

  	scsi_req->cdb[1] = 0;
  	scsi_req->cdb[2] = 0;
  	scsi_req->cdb[3] = 0;
  	scsi_req->cdb[4] = 0;
  	scsi_req->cdb[5] = 0;
  	scsi_req->cdb[6] = 0;
  	scsi_req->cdb[7] = 0;
  	scsi_req->cdb[8] = 0;
  	scsi_req->cdb[9] = 0;
  }

  /*
   * Return true if and only if all pending requests should be failed.
   */
  static bool skd_fail_all(struct request_queue *q)

  {
  	struct skd_device *skdev = q->queuedata;
  
  	SKD_ASSERT(skdev->state != SKD_DRVR_STATE_ONLINE);
  
  	skd_log_skdev(skdev, "req_not_online");
  	switch (skdev->state) {
  	case SKD_DRVR_STATE_PAUSING:
  	case SKD_DRVR_STATE_PAUSED:
  	case SKD_DRVR_STATE_STARTING:
  	case SKD_DRVR_STATE_RESTARTING:
  	case SKD_DRVR_STATE_WAIT_BOOT:
  	/* In case of starting, we haven't started the queue,
  	 * so we can't get here... but requests are
  	 * possibly hanging out waiting for us because we
  	 * reported the dev/skd0 already.  They'll wait
  	 * forever if connect doesn't complete.
  	 * What to do??? delay dev/skd0 ??
  	 */
  	case SKD_DRVR_STATE_BUSY:
  	case SKD_DRVR_STATE_BUSY_IMMINENT:
  	case SKD_DRVR_STATE_BUSY_ERASE:

  		return false;

  
  	case SKD_DRVR_STATE_BUSY_SANITIZE:
  	case SKD_DRVR_STATE_STOPPING:
  	case SKD_DRVR_STATE_SYNCING:
  	case SKD_DRVR_STATE_FAULT:
  	case SKD_DRVR_STATE_DISAPPEARED:
  	default:

  		return true;

  	}

  }

  static blk_status_t skd_mq_queue_rq(struct blk_mq_hw_ctx *hctx,
  				    const struct blk_mq_queue_data *mqd)

  {

  	struct request *const req = mqd->rq;

  	struct request_queue *const q = req->q;

  	struct skd_device *skdev = q->queuedata;

  	struct skd_fitmsg_context *skmsg;
  	struct fit_msg_hdr *fmh;
  	const u32 tag = blk_mq_unique_tag(req);

  	struct skd_request_context *const skreq = blk_mq_rq_to_pdu(req);

  	struct skd_scsi_request *scsi_req;

  	unsigned long flags = 0;

  	const u32 lba = blk_rq_pos(req);
  	const u32 count = blk_rq_sectors(req);
  	const int data_dir = rq_data_dir(req);

  	if (unlikely(skdev->state != SKD_DRVR_STATE_ONLINE))
  		return skd_fail_all(q) ? BLK_STS_IOERR : BLK_STS_RESOURCE;
  
  	blk_mq_start_request(req);

  	WARN_ONCE(tag >= skd_max_queue_depth, "%#x > %#x (nr_requests = %lu)
  ",
  		  tag, skd_max_queue_depth, q->nr_requests);
  
  	SKD_ASSERT(skreq->state == SKD_REQ_STATE_IDLE);

  	dev_dbg(&skdev->pdev->dev,
  		"new req=%p lba=%u(0x%x) count=%u(0x%x) dir=%d
  ", req, lba,
  		lba, count, count, data_dir);
  
  	skreq->id = tag + SKD_ID_RW_REQUEST;
  	skreq->flush_cmd = 0;
  	skreq->n_sg = 0;
  	skreq->sg_byte_count = 0;

  	skreq->fitmsg_id = 0;
  
  	skreq->data_dir = data_dir == READ ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
  
  	if (req->bio && !skd_preop_sg_list(skdev, skreq)) {
  		dev_dbg(&skdev->pdev->dev, "error Out
  ");

  		skreq->status = BLK_STS_RESOURCE;
  		blk_mq_complete_request(req);

  		return BLK_STS_OK;

  	}

  	dma_sync_single_for_device(&skdev->pdev->dev, skreq->sksg_dma_address,
  				   skreq->n_sg *
  				   sizeof(struct fit_sg_descriptor),
  				   DMA_TO_DEVICE);

  	/* Either a FIT msg is in progress or we have to start one. */

  	if (skd_max_req_per_msg == 1) {
  		skmsg = NULL;
  	} else {
  		spin_lock_irqsave(&skdev->lock, flags);
  		skmsg = skdev->skmsg;
  	}

  	if (!skmsg) {
  		skmsg = &skdev->skmsg_table[tag];
  		skdev->skmsg = skmsg;
  
  		/* Initialize the FIT msg header */
  		fmh = &skmsg->msg_buf->fmh;
  		memset(fmh, 0, sizeof(*fmh));
  		fmh->protocol_id = FIT_PROTOCOL_ID_SOFIT;
  		skmsg->length = sizeof(*fmh);
  	} else {
  		fmh = &skmsg->msg_buf->fmh;
  	}
  
  	skreq->fitmsg_id = skmsg->id;
  
  	scsi_req = &skmsg->msg_buf->scsi[fmh->num_protocol_cmds_coalesced];
  	memset(scsi_req, 0, sizeof(*scsi_req));

  	scsi_req->hdr.tag = skreq->id;

  	scsi_req->hdr.sg_list_dma_address =
  		cpu_to_be64(skreq->sksg_dma_address);

  	if (req_op(req) == REQ_OP_FLUSH) {

  		skd_prep_zerosize_flush_cdb(scsi_req, skreq);
  		SKD_ASSERT(skreq->flush_cmd == 1);
  	} else {
  		skd_prep_rw_cdb(scsi_req, data_dir, lba, count);
  	}

  	if (req->cmd_flags & REQ_FUA)

  		scsi_req->cdb[1] |= SKD_FUA_NV;
  
  	scsi_req->hdr.sg_list_len_bytes = cpu_to_be32(skreq->sg_byte_count);
  
  	/* Complete resource allocations. */
  	skreq->state = SKD_REQ_STATE_BUSY;
  
  	skmsg->length += sizeof(struct skd_scsi_request);
  	fmh->num_protocol_cmds_coalesced++;

  	dev_dbg(&skdev->pdev->dev, "req=0x%x busy=%d
  ", skreq->id,

  		skd_in_flight(skdev));

  
  	/*
  	 * If the FIT msg buffer is full send it.
  	 */

  	if (skd_max_req_per_msg == 1) {

  		skd_send_fitmsg(skdev, skmsg);

  	} else {

  		if (mqd->last ||

  		    fmh->num_protocol_cmds_coalesced >= skd_max_req_per_msg) {
  			skd_send_fitmsg(skdev, skmsg);
  			skdev->skmsg = NULL;
  		}
  		spin_unlock_irqrestore(&skdev->lock, flags);

  	}

  	return BLK_STS_OK;

  }

  static enum blk_eh_timer_return skd_timed_out(struct request *req,
  					      bool reserved)

  {
  	struct skd_device *skdev = req->q->queuedata;
  
  	dev_err(&skdev->pdev->dev, "request with tag %#x timed out
  ",
  		blk_mq_unique_tag(req));

  	return BLK_EH_RESET_TIMER;

  }

  static void skd_complete_rq(struct request *req)

  {

  	struct skd_request_context *skreq = blk_mq_rq_to_pdu(req);

  	blk_mq_end_request(req, skreq->status);

  }

  static bool skd_preop_sg_list(struct skd_device *skdev,

  			     struct skd_request_context *skreq)

  {

  	struct request *req = blk_mq_rq_from_pdu(skreq);

  	struct scatterlist *sgl = &skreq->sg[0], *sg;

  	int n_sg;
  	int i;
  
  	skreq->sg_byte_count = 0;

  	WARN_ON_ONCE(skreq->data_dir != DMA_TO_DEVICE &&
  		     skreq->data_dir != DMA_FROM_DEVICE);

  	n_sg = blk_rq_map_sg(skdev->queue, req, sgl);

  	if (n_sg <= 0)

  		return false;

  
  	/*
  	 * Map scatterlist to PCI bus addresses.
  	 * Note PCI might change the number of entries.
  	 */

  	n_sg = pci_map_sg(skdev->pdev, sgl, n_sg, skreq->data_dir);

  	if (n_sg <= 0)

  		return false;

  
  	SKD_ASSERT(n_sg <= skdev->sgs_per_request);
  
  	skreq->n_sg = n_sg;

  	for_each_sg(sgl, sg, n_sg, i) {

  		struct fit_sg_descriptor *sgd = &skreq->sksg_list[i];

  		u32 cnt = sg_dma_len(sg);
  		uint64_t dma_addr = sg_dma_address(sg);

  
  		sgd->control = FIT_SGD_CONTROL_NOT_LAST;
  		sgd->byte_count = cnt;
  		skreq->sg_byte_count += cnt;
  		sgd->host_side_addr = dma_addr;
  		sgd->dev_side_addr = 0;
  	}
  
  	skreq->sksg_list[n_sg - 1].next_desc_ptr = 0LL;
  	skreq->sksg_list[n_sg - 1].control = FIT_SGD_CONTROL_LAST;
  
  	if (unlikely(skdev->dbg_level > 1)) {

  		dev_dbg(&skdev->pdev->dev,
  			"skreq=%x sksg_list=%p sksg_dma=%llx
  ",
  			skreq->id, skreq->sksg_list, skreq->sksg_dma_address);

  		for (i = 0; i < n_sg; i++) {
  			struct fit_sg_descriptor *sgd = &skreq->sksg_list[i];

  
  			dev_dbg(&skdev->pdev->dev,
  				"  sg[%d] count=%u ctrl=0x%x addr=0x%llx next=0x%llx
  ",
  				i, sgd->byte_count, sgd->control,
  				sgd->host_side_addr, sgd->next_desc_ptr);

  		}
  	}

  	return true;

  }

  static void skd_postop_sg_list(struct skd_device *skdev,

  			       struct skd_request_context *skreq)

  {

  	/*
  	 * restore the next ptr for next IO request so we
  	 * don't have to set it every time.
  	 */
  	skreq->sksg_list[skreq->n_sg - 1].next_desc_ptr =
  		skreq->sksg_dma_address +
  		((skreq->n_sg) * sizeof(struct fit_sg_descriptor));

  	pci_unmap_sg(skdev->pdev, &skreq->sg[0], skreq->n_sg, skreq->data_dir);

  }

  /*
   *****************************************************************************
   * TIMER
   *****************************************************************************
   */
  
  static void skd_timer_tick_not_online(struct skd_device *skdev);

  static void skd_start_queue(struct work_struct *work)
  {
  	struct skd_device *skdev = container_of(work, typeof(*skdev),
  						start_queue);
  
  	/*
  	 * Although it is safe to call blk_start_queue() from interrupt
  	 * context, blk_mq_start_hw_queues() must not be called from
  	 * interrupt context.
  	 */
  	blk_mq_start_hw_queues(skdev->queue);
  }

  static void skd_timer_tick(ulong arg)
  {
  	struct skd_device *skdev = (struct skd_device *)arg;

  	unsigned long reqflags;
  	u32 state;
  
  	if (skdev->state == SKD_DRVR_STATE_FAULT)
  		/* The driver has declared fault, and we want it to
  		 * stay that way until driver is reloaded.
  		 */
  		return;
  
  	spin_lock_irqsave(&skdev->lock, reqflags);
  
  	state = SKD_READL(skdev, FIT_STATUS);
  	state &= FIT_SR_DRIVE_STATE_MASK;
  	if (state != skdev->drive_state)
  		skd_isr_fwstate(skdev);

  	if (skdev->state != SKD_DRVR_STATE_ONLINE)

  		skd_timer_tick_not_online(skdev);

  	mod_timer(&skdev->timer, (jiffies + HZ));
  
  	spin_unlock_irqrestore(&skdev->lock, reqflags);
  }
  
  static void skd_timer_tick_not_online(struct skd_device *skdev)
  {
  	switch (skdev->state) {
  	case SKD_DRVR_STATE_IDLE:
  	case SKD_DRVR_STATE_LOAD:
  		break;
  	case SKD_DRVR_STATE_BUSY_SANITIZE:

  		dev_dbg(&skdev->pdev->dev,
  			"drive busy sanitize[%x], driver[%x]
  ",
  			skdev->drive_state, skdev->state);

  		/* If we've been in sanitize for 3 seconds, we figure we're not
  		 * going to get anymore completions, so recover requests now
  		 */
  		if (skdev->timer_countdown > 0) {
  			skdev->timer_countdown--;
  			return;
  		}

  		skd_recover_requests(skdev);

  		break;
  
  	case SKD_DRVR_STATE_BUSY:
  	case SKD_DRVR_STATE_BUSY_IMMINENT:
  	case SKD_DRVR_STATE_BUSY_ERASE:

  		dev_dbg(&skdev->pdev->dev, "busy[%x], countdown=%d
  ",
  			skdev->state, skdev->timer_countdown);

  		if (skdev->timer_countdown > 0) {
  			skdev->timer_countdown--;
  			return;
  		}

  		dev_dbg(&skdev->pdev->dev,
  			"busy[%x], timedout=%d, restarting device.",
  			skdev->state, skdev->timer_countdown);

  		skd_restart_device(skdev);
  		break;
  
  	case SKD_DRVR_STATE_WAIT_BOOT:
  	case SKD_DRVR_STATE_STARTING:
  		if (skdev->timer_countdown > 0) {
  			skdev->timer_countdown--;
  			return;
  		}
  		/* For now, we fault the drive.  Could attempt resets to
  		 * revcover at some point. */
  		skdev->state = SKD_DRVR_STATE_FAULT;

  		dev_err(&skdev->pdev->dev, "DriveFault Connect Timeout (%x)
  ",
  			skdev->drive_state);

  
  		/*start the queue so we can respond with error to requests */
  		/* wakeup anyone waiting for startup complete */

  		schedule_work(&skdev->start_queue);

  		skdev->gendisk_on = -1;
  		wake_up_interruptible(&skdev->waitq);
  		break;
  
  	case SKD_DRVR_STATE_ONLINE:
  		/* shouldn't get here. */
  		break;
  
  	case SKD_DRVR_STATE_PAUSING:
  	case SKD_DRVR_STATE_PAUSED:
  		break;

  	case SKD_DRVR_STATE_RESTARTING:
  		if (skdev->timer_countdown > 0) {
  			skdev->timer_countdown--;
  			return;
  		}
  		/* For now, we fault the drive. Could attempt resets to
  		 * revcover at some point. */
  		skdev->state = SKD_DRVR_STATE_FAULT;

  		dev_err(&skdev->pdev->dev,
  			"DriveFault Reconnect Timeout (%x)
  ",
  			skdev->drive_state);

  
  		/*
  		 * Recovering does two things:
  		 * 1. completes IO with error
  		 * 2. reclaims dma resources
  		 * When is it safe to recover requests?
  		 * - if the drive state is faulted
  		 * - if the state is still soft reset after out timeout
  		 * - if the drive registers are dead (state = FF)
  		 * If it is "unsafe", we still need to recover, so we will
  		 * disable pci bus mastering and disable our interrupts.
  		 */
  
  		if ((skdev->drive_state == FIT_SR_DRIVE_SOFT_RESET) ||
  		    (skdev->drive_state == FIT_SR_DRIVE_FAULT) ||
  		    (skdev->drive_state == FIT_SR_DRIVE_STATE_MASK))
  			/* It never came out of soft reset. Try to
  			 * recover the requests and then let them
  			 * fail. This is to mitigate hung processes. */

  			skd_recover_requests(skdev);

  		else {

  			dev_err(&skdev->pdev->dev, "Disable BusMaster (%x)
  ",
  				skdev->drive_state);

  			pci_disable_device(skdev->pdev);
  			skd_disable_interrupts(skdev);

  			skd_recover_requests(skdev);

  		}
  
  		/*start the queue so we can respond with error to requests */
  		/* wakeup anyone waiting for startup complete */

  		schedule_work(&skdev->start_queue);

  		skdev->gendisk_on = -1;
  		wake_up_interruptible(&skdev->waitq);
  		break;
  
  	case SKD_DRVR_STATE_RESUMING:
  	case SKD_DRVR_STATE_STOPPING:
  	case SKD_DRVR_STATE_SYNCING:
  	case SKD_DRVR_STATE_FAULT:
  	case SKD_DRVR_STATE_DISAPPEARED:
  	default:
  		break;
  	}
  }
  
  static int skd_start_timer(struct skd_device *skdev)
  {
  	int rc;

  	setup_timer(&skdev->timer, skd_timer_tick, (ulong)skdev);
  
  	rc = mod_timer(&skdev->timer, (jiffies + HZ));
  	if (rc)

  		dev_err(&skdev->pdev->dev, "failed to start timer %d
  ", rc);

  	return rc;
  }
  
  static void skd_kill_timer(struct skd_device *skdev)
  {
  	del_timer_sync(&skdev->timer);
  }
  
  /*
   *****************************************************************************

   * INTERNAL REQUESTS -- generated by driver itself
   *****************************************************************************
   */
  
  static int skd_format_internal_skspcl(struct skd_device *skdev)
  {
  	struct skd_special_context *skspcl = &skdev->internal_skspcl;
  	struct fit_sg_descriptor *sgd = &skspcl->req.sksg_list[0];
  	struct fit_msg_hdr *fmh;
  	uint64_t dma_address;
  	struct skd_scsi_request *scsi;

  	fmh = &skspcl->msg_buf->fmh;

  	fmh->protocol_id = FIT_PROTOCOL_ID_SOFIT;
  	fmh->num_protocol_cmds_coalesced = 1;

  	scsi = &skspcl->msg_buf->scsi[0];

  	memset(scsi, 0, sizeof(*scsi));
  	dma_address = skspcl->req.sksg_dma_address;
  	scsi->hdr.sg_list_dma_address = cpu_to_be64(dma_address);

  	skspcl->req.n_sg = 1;

  	sgd->control = FIT_SGD_CONTROL_LAST;
  	sgd->byte_count = 0;
  	sgd->host_side_addr = skspcl->db_dma_address;
  	sgd->dev_side_addr = 0;
  	sgd->next_desc_ptr = 0LL;
  
  	return 1;
  }
  
  #define WR_BUF_SIZE SKD_N_INTERNAL_BYTES
  
  static void skd_send_internal_skspcl(struct skd_device *skdev,
  				     struct skd_special_context *skspcl,
  				     u8 opcode)
  {
  	struct fit_sg_descriptor *sgd = &skspcl->req.sksg_list[0];
  	struct skd_scsi_request *scsi;
  	unsigned char *buf = skspcl->data_buf;
  	int i;
  
  	if (skspcl->req.state != SKD_REQ_STATE_IDLE)
  		/*
  		 * A refresh is already in progress.
  		 * Just wait for it to finish.
  		 */
  		return;

  	skspcl->req.state = SKD_REQ_STATE_BUSY;

  	scsi = &skspcl->msg_buf->scsi[0];

  	scsi->hdr.tag = skspcl->req.id;
  
  	memset(scsi->cdb, 0, sizeof(scsi->cdb));
  
  	switch (opcode) {
  	case TEST_UNIT_READY:
  		scsi->cdb[0] = TEST_UNIT_READY;
  		sgd->byte_count = 0;
  		scsi->hdr.sg_list_len_bytes = 0;
  		break;
  
  	case READ_CAPACITY:
  		scsi->cdb[0] = READ_CAPACITY;
  		sgd->byte_count = SKD_N_READ_CAP_BYTES;
  		scsi->hdr.sg_list_len_bytes = cpu_to_be32(sgd->byte_count);
  		break;
  
  	case INQUIRY:
  		scsi->cdb[0] = INQUIRY;
  		scsi->cdb[1] = 0x01;    /* evpd */
  		scsi->cdb[2] = 0x80;    /* serial number page */
  		scsi->cdb[4] = 0x10;
  		sgd->byte_count = 16;
  		scsi->hdr.sg_list_len_bytes = cpu_to_be32(sgd->byte_count);
  		break;
  
  	case SYNCHRONIZE_CACHE:
  		scsi->cdb[0] = SYNCHRONIZE_CACHE;
  		sgd->byte_count = 0;
  		scsi->hdr.sg_list_len_bytes = 0;
  		break;
  
  	case WRITE_BUFFER:
  		scsi->cdb[0] = WRITE_BUFFER;
  		scsi->cdb[1] = 0x02;
  		scsi->cdb[7] = (WR_BUF_SIZE & 0xFF00) >> 8;
  		scsi->cdb[8] = WR_BUF_SIZE & 0xFF;
  		sgd->byte_count = WR_BUF_SIZE;
  		scsi->hdr.sg_list_len_bytes = cpu_to_be32(sgd->byte_count);
  		/* fill incrementing byte pattern */
  		for (i = 0; i < sgd->byte_count; i++)
  			buf[i] = i & 0xFF;
  		break;
  
  	case READ_BUFFER:
  		scsi->cdb[0] = READ_BUFFER;
  		scsi->cdb[1] = 0x02;
  		scsi->cdb[7] = (WR_BUF_SIZE & 0xFF00) >> 8;
  		scsi->cdb[8] = WR_BUF_SIZE & 0xFF;
  		sgd->byte_count = WR_BUF_SIZE;
  		scsi->hdr.sg_list_len_bytes = cpu_to_be32(sgd->byte_count);
  		memset(skspcl->data_buf, 0, sgd->byte_count);
  		break;
  
  	default:
  		SKD_ASSERT("Don't know what to send");
  		return;
  
  	}
  	skd_send_special_fitmsg(skdev, skspcl);
  }
  
  static void skd_refresh_device_data(struct skd_device *skdev)
  {
  	struct skd_special_context *skspcl = &skdev->internal_skspcl;
  
  	skd_send_internal_skspcl(skdev, skspcl, TEST_UNIT_READY);
  }
  
  static int skd_chk_read_buf(struct skd_device *skdev,
  			    struct skd_special_context *skspcl)
  {
  	unsigned char *buf = skspcl->data_buf;
  	int i;
  
  	/* check for incrementing byte pattern */
  	for (i = 0; i < WR_BUF_SIZE; i++)
  		if (buf[i] != (i & 0xFF))
  			return 1;
  
  	return 0;
  }
  
  static void skd_log_check_status(struct skd_device *skdev, u8 status, u8 key,
  				 u8 code, u8 qual, u8 fruc)
  {
  	/* If the check condition is of special interest, log a message */
  	if ((status == SAM_STAT_CHECK_CONDITION) && (key == 0x02)
  	    && (code == 0x04) && (qual == 0x06)) {

  		dev_err(&skdev->pdev->dev,
  			"*** LOST_WRITE_DATA ERROR *** key/asc/ascq/fruc %02x/%02x/%02x/%02x
  ",
  			key, code, qual, fruc);

  	}
  }
  
  static void skd_complete_internal(struct skd_device *skdev,

  				  struct fit_completion_entry_v1 *skcomp,
  				  struct fit_comp_error_info *skerr,

  				  struct skd_special_context *skspcl)
  {
  	u8 *buf = skspcl->data_buf;
  	u8 status;
  	int i;

  	struct skd_scsi_request *scsi = &skspcl->msg_buf->scsi[0];

  	lockdep_assert_held(&skdev->lock);

  	SKD_ASSERT(skspcl == &skdev->internal_skspcl);

  	dev_dbg(&skdev->pdev->dev, "complete internal %x
  ", scsi->cdb[0]);

  	dma_sync_single_for_cpu(&skdev->pdev->dev,
  				skspcl->db_dma_address,
  				skspcl->req.sksg_list[0].byte_count,
  				DMA_BIDIRECTIONAL);

  	skspcl->req.completion = *skcomp;
  	skspcl->req.state = SKD_REQ_STATE_IDLE;

  
  	status = skspcl->req.completion.status;
  
  	skd_log_check_status(skdev, status, skerr->key, skerr->code,
  			     skerr->qual, skerr->fruc);
  
  	switch (scsi->cdb[0]) {
  	case TEST_UNIT_READY:
  		if (status == SAM_STAT_GOOD)
  			skd_send_internal_skspcl(skdev, skspcl, WRITE_BUFFER);
  		else if ((status == SAM_STAT_CHECK_CONDITION) &&
  			 (skerr->key == MEDIUM_ERROR))
  			skd_send_internal_skspcl(skdev, skspcl, WRITE_BUFFER);
  		else {
  			if (skdev->state == SKD_DRVR_STATE_STOPPING) {

  				dev_dbg(&skdev->pdev->dev,
  					"TUR failed, don't send anymore state 0x%x
  ",
  					skdev->state);

  				return;
  			}

  			dev_dbg(&skdev->pdev->dev,
  				"**** TUR failed, retry skerr
  ");

  			skd_send_internal_skspcl(skdev, skspcl,
  						 TEST_UNIT_READY);

  		}
  		break;
  
  	case WRITE_BUFFER:
  		if (status == SAM_STAT_GOOD)
  			skd_send_internal_skspcl(skdev, skspcl, READ_BUFFER);
  		else {
  			if (skdev->state == SKD_DRVR_STATE_STOPPING) {

  				dev_dbg(&skdev->pdev->dev,
  					"write buffer failed, don't send anymore state 0x%x
  ",
  					skdev->state);

  				return;
  			}

  			dev_dbg(&skdev->pdev->dev,
  				"**** write buffer failed, retry skerr
  ");

  			skd_send_internal_skspcl(skdev, skspcl,
  						 TEST_UNIT_READY);

  		}
  		break;
  
  	case READ_BUFFER:
  		if (status == SAM_STAT_GOOD) {
  			if (skd_chk_read_buf(skdev, skspcl) == 0)
  				skd_send_internal_skspcl(skdev, skspcl,
  							 READ_CAPACITY);
  			else {

  				dev_err(&skdev->pdev->dev,
  					"*** W/R Buffer mismatch %d ***
  ",
  					skdev->connect_retries);

  				if (skdev->connect_retries <
  				    SKD_MAX_CONNECT_RETRIES) {
  					skdev->connect_retries++;
  					skd_soft_reset(skdev);
  				} else {

  					dev_err(&skdev->pdev->dev,
  						"W/R Buffer Connect Error
  ");

  					return;
  				}
  			}
  
  		} else {
  			if (skdev->state == SKD_DRVR_STATE_STOPPING) {

  				dev_dbg(&skdev->pdev->dev,
  					"read buffer failed, don't send anymore state 0x%x
  ",
  					skdev->state);

  				return;
  			}

  			dev_dbg(&skdev->pdev->dev,
  				"**** read buffer failed, retry skerr
  ");

  			skd_send_internal_skspcl(skdev, skspcl,
  						 TEST_UNIT_READY);

  		}
  		break;
  
  	case READ_CAPACITY:
  		skdev->read_cap_is_valid = 0;
  		if (status == SAM_STAT_GOOD) {
  			skdev->read_cap_last_lba =
  				(buf[0] << 24) | (buf[1] << 16) |
  				(buf[2] << 8) | buf[3];
  			skdev->read_cap_blocksize =
  				(buf[4] << 24) | (buf[5] << 16) |
  				(buf[6] << 8) | buf[7];

  			dev_dbg(&skdev->pdev->dev, "last lba %d, bs %d
  ",
  				skdev->read_cap_last_lba,
  				skdev->read_cap_blocksize);

  
  			set_capacity(skdev->disk, skdev->read_cap_last_lba + 1);
  
  			skdev->read_cap_is_valid = 1;
  
  			skd_send_internal_skspcl(skdev, skspcl, INQUIRY);
  		} else if ((status == SAM_STAT_CHECK_CONDITION) &&
  			   (skerr->key == MEDIUM_ERROR)) {
  			skdev->read_cap_last_lba = ~0;
  			set_capacity(skdev->disk, skdev->read_cap_last_lba + 1);

  			dev_dbg(&skdev->pdev->dev, "**** MEDIUM ERROR caused READCAP to fail, ignore failure and continue to inquiry
  ");

  			skd_send_internal_skspcl(skdev, skspcl, INQUIRY);
  		} else {

  			dev_dbg(&skdev->pdev->dev, "**** READCAP failed, retry TUR
  ");

  			skd_send_internal_skspcl(skdev, skspcl,
  						 TEST_UNIT_READY);
  		}
  		break;
  
  	case INQUIRY:
  		skdev->inquiry_is_valid = 0;
  		if (status == SAM_STAT_GOOD) {
  			skdev->inquiry_is_valid = 1;
  
  			for (i = 0; i < 12; i++)
  				skdev->inq_serial_num[i] = buf[i + 4];
  			skdev->inq_serial_num[12] = 0;
  		}
  
  		if (skd_unquiesce_dev(skdev) < 0)

  			dev_dbg(&skdev->pdev->dev, "**** failed, to ONLINE device
  ");

  		 /* connection is complete */
  		skdev->connect_retries = 0;
  		break;
  
  	case SYNCHRONIZE_CACHE:
  		if (status == SAM_STAT_GOOD)
  			skdev->sync_done = 1;
  		else
  			skdev->sync_done = -1;
  		wake_up_interruptible(&skdev->waitq);
  		break;
  
  	default:
  		SKD_ASSERT("we didn't send this");
  	}
  }
  
  /*
   *****************************************************************************
   * FIT MESSAGES
   *****************************************************************************
   */
  
  static void skd_send_fitmsg(struct skd_device *skdev,
  			    struct skd_fitmsg_context *skmsg)
  {
  	u64 qcmd;

  	dev_dbg(&skdev->pdev->dev, "dma address 0x%llx, busy=%d
  ",

  		skmsg->mb_dma_address, skd_in_flight(skdev));

  	dev_dbg(&skdev->pdev->dev, "msg_buf %p
  ", skmsg->msg_buf);

  
  	qcmd = skmsg->mb_dma_address;
  	qcmd |= FIT_QCMD_QID_NORMAL;

  	if (unlikely(skdev->dbg_level > 1)) {
  		u8 *bp = (u8 *)skmsg->msg_buf;
  		int i;
  		for (i = 0; i < skmsg->length; i += 8) {

  			dev_dbg(&skdev->pdev->dev, "msg[%2d] %8ph
  ", i,
  				&bp[i]);

  			if (i == 0)
  				i = 64 - 8;
  		}
  	}
  
  	if (skmsg->length > 256)
  		qcmd |= FIT_QCMD_MSGSIZE_512;
  	else if (skmsg->length > 128)
  		qcmd |= FIT_QCMD_MSGSIZE_256;
  	else if (skmsg->length > 64)
  		qcmd |= FIT_QCMD_MSGSIZE_128;
  	else
  		/*
  		 * This makes no sense because the FIT msg header is
  		 * 64 bytes. If the msg is only 64 bytes long it has
  		 * no payload.
  		 */
  		qcmd |= FIT_QCMD_MSGSIZE_64;

  	dma_sync_single_for_device(&skdev->pdev->dev, skmsg->mb_dma_address,
  				   skmsg->length, DMA_TO_DEVICE);

  	/* Make sure skd_msg_buf is written before the doorbell is triggered. */
  	smp_wmb();

  	SKD_WRITEQ(skdev, qcmd, FIT_Q_COMMAND);

  }
  
  static void skd_send_special_fitmsg(struct skd_device *skdev,
  				    struct skd_special_context *skspcl)
  {
  	u64 qcmd;

  	WARN_ON_ONCE(skspcl->req.n_sg != 1);

  	if (unlikely(skdev->dbg_level > 1)) {
  		u8 *bp = (u8 *)skspcl->msg_buf;
  		int i;
  
  		for (i = 0; i < SKD_N_SPECIAL_FITMSG_BYTES; i += 8) {

  			dev_dbg(&skdev->pdev->dev, " spcl[%2d] %8ph
  ", i,
  				&bp[i]);

  			if (i == 0)
  				i = 64 - 8;
  		}

  		dev_dbg(&skdev->pdev->dev,
  			"skspcl=%p id=%04x sksg_list=%p sksg_dma=%llx
  ",
  			skspcl, skspcl->req.id, skspcl->req.sksg_list,
  			skspcl->req.sksg_dma_address);

  		for (i = 0; i < skspcl->req.n_sg; i++) {
  			struct fit_sg_descriptor *sgd =
  				&skspcl->req.sksg_list[i];

  			dev_dbg(&skdev->pdev->dev,
  				"  sg[%d] count=%u ctrl=0x%x addr=0x%llx next=0x%llx
  ",
  				i, sgd->byte_count, sgd->control,
  				sgd->host_side_addr, sgd->next_desc_ptr);

  		}
  	}
  
  	/*
  	 * Special FIT msgs are always 128 bytes: a 64-byte FIT hdr
  	 * and one 64-byte SSDI command.
  	 */
  	qcmd = skspcl->mb_dma_address;
  	qcmd |= FIT_QCMD_QID_NORMAL + FIT_QCMD_MSGSIZE_128;

  	dma_sync_single_for_device(&skdev->pdev->dev, skspcl->mb_dma_address,
  				   SKD_N_SPECIAL_FITMSG_BYTES, DMA_TO_DEVICE);
  	dma_sync_single_for_device(&skdev->pdev->dev,
  				   skspcl->req.sksg_dma_address,
  				   1 * sizeof(struct fit_sg_descriptor),
  				   DMA_TO_DEVICE);
  	dma_sync_single_for_device(&skdev->pdev->dev,
  				   skspcl->db_dma_address,
  				   skspcl->req.sksg_list[0].byte_count,
  				   DMA_BIDIRECTIONAL);

  	/* Make sure skd_msg_buf is written before the doorbell is triggered. */
  	smp_wmb();

  	SKD_WRITEQ(skdev, qcmd, FIT_Q_COMMAND);
  }
  
  /*
   *****************************************************************************
   * COMPLETION QUEUE
   *****************************************************************************
   */
  
  static void skd_complete_other(struct skd_device *skdev,

  			       struct fit_completion_entry_v1 *skcomp,
  			       struct fit_comp_error_info *skerr);

  struct sns_info {
  	u8 type;
  	u8 stat;
  	u8 key;
  	u8 asc;
  	u8 ascq;
  	u8 mask;
  	enum skd_check_status_action action;
  };
  
  static struct sns_info skd_chkstat_table[] = {
  	/* Good */
  	{ 0x70, 0x02, RECOVERED_ERROR, 0,    0,	   0x1c,
  	  SKD_CHECK_STATUS_REPORT_GOOD },
  
  	/* Smart alerts */
  	{ 0x70, 0x02, NO_SENSE,	       0x0B, 0x00, 0x1E,	/* warnings */
  	  SKD_CHECK_STATUS_REPORT_SMART_ALERT },
  	{ 0x70, 0x02, NO_SENSE,	       0x5D, 0x00, 0x1E,	/* thresholds */
  	  SKD_CHECK_STATUS_REPORT_SMART_ALERT },
  	{ 0x70, 0x02, RECOVERED_ERROR, 0x0B, 0x01, 0x1F,        /* temperature over trigger */
  	  SKD_CHECK_STATUS_REPORT_SMART_ALERT },
  
  	/* Retry (with limits) */
  	{ 0x70, 0x02, 0x0B,	       0,    0,	   0x1C,        /* This one is for DMA ERROR */
  	  SKD_CHECK_STATUS_REQUEUE_REQUEST },
  	{ 0x70, 0x02, 0x06,	       0x0B, 0x00, 0x1E,        /* warnings */
  	  SKD_CHECK_STATUS_REQUEUE_REQUEST },
  	{ 0x70, 0x02, 0x06,	       0x5D, 0x00, 0x1E,        /* thresholds */
  	  SKD_CHECK_STATUS_REQUEUE_REQUEST },
  	{ 0x70, 0x02, 0x06,	       0x80, 0x30, 0x1F,        /* backup power */
  	  SKD_CHECK_STATUS_REQUEUE_REQUEST },
  
  	/* Busy (or about to be) */
  	{ 0x70, 0x02, 0x06,	       0x3f, 0x01, 0x1F, /* fw changed */
  	  SKD_CHECK_STATUS_BUSY_IMMINENT },
  };
  
  /*
   * Look up status and sense data to decide how to handle the error
   * from the device.
   * mask says which fields must match e.g., mask=0x18 means check
   * type and stat, ignore key, asc, ascq.
   */

  static enum skd_check_status_action
  skd_check_status(struct skd_device *skdev,

  		 u8 cmp_status, struct fit_comp_error_info *skerr)

  {

  	int i;

  	dev_err(&skdev->pdev->dev, "key/asc/ascq/fruc %02x/%02x/%02x/%02x
  ",
  		skerr->key, skerr->code, skerr->qual, skerr->fruc);

  	dev_dbg(&skdev->pdev->dev,
  		"stat: t=%02x stat=%02x k=%02x c=%02x q=%02x fruc=%02x
  ",
  		skerr->type, cmp_status, skerr->key, skerr->code, skerr->qual,
  		skerr->fruc);

  
  	/* Does the info match an entry in the good category? */

  	for (i = 0; i < ARRAY_SIZE(skd_chkstat_table); i++) {

  		struct sns_info *sns = &skd_chkstat_table[i];
  
  		if (sns->mask & 0x10)
  			if (skerr->type != sns->type)
  				continue;
  
  		if (sns->mask & 0x08)
  			if (cmp_status != sns->stat)
  				continue;
  
  		if (sns->mask & 0x04)
  			if (skerr->key != sns->key)
  				continue;
  
  		if (sns->mask & 0x02)
  			if (skerr->code != sns->asc)
  				continue;
  
  		if (sns->mask & 0x01)
  			if (skerr->qual != sns->ascq)
  				continue;
  
  		if (sns->action == SKD_CHECK_STATUS_REPORT_SMART_ALERT) {

  			dev_err(&skdev->pdev->dev,
  				"SMART Alert: sense key/asc/ascq %02x/%02x/%02x
  ",
  				skerr->key, skerr->code, skerr->qual);

  		}
  		return sns->action;
  	}
  
  	/* No other match, so nonzero status means error,
  	 * zero status means good
  	 */
  	if (cmp_status) {

  		dev_dbg(&skdev->pdev->dev, "status check: error
  ");

  		return SKD_CHECK_STATUS_REPORT_ERROR;
  	}

  	dev_dbg(&skdev->pdev->dev, "status check good default
  ");

  	return SKD_CHECK_STATUS_REPORT_GOOD;
  }
  
  static void skd_resolve_req_exception(struct skd_device *skdev,

  				      struct skd_request_context *skreq,
  				      struct request *req)

  {
  	u8 cmp_status = skreq->completion.status;
  
  	switch (skd_check_status(skdev, cmp_status, &skreq->err_info)) {
  	case SKD_CHECK_STATUS_REPORT_GOOD:
  	case SKD_CHECK_STATUS_REPORT_SMART_ALERT:

  		skreq->status = BLK_STS_OK;
  		blk_mq_complete_request(req);

  		break;
  
  	case SKD_CHECK_STATUS_BUSY_IMMINENT:
  		skd_log_skreq(skdev, skreq, "retry(busy)");

  		blk_requeue_request(skdev->queue, req);

  		dev_info(&skdev->pdev->dev, "drive BUSY imminent
  ");

  		skdev->state = SKD_DRVR_STATE_BUSY_IMMINENT;
  		skdev->timer_countdown = SKD_TIMER_MINUTES(20);
  		skd_quiesce_dev(skdev);
  		break;
  
  	case SKD_CHECK_STATUS_REQUEUE_REQUEST:

  		if ((unsigned long) ++req->special < SKD_MAX_RETRIES) {

  			skd_log_skreq(skdev, skreq, "retry");

  			blk_requeue_request(skdev->queue, req);

  			break;

  		}

  		/* fall through */

  
  	case SKD_CHECK_STATUS_REPORT_ERROR:
  	default:

  		skreq->status = BLK_STS_IOERR;
  		blk_mq_complete_request(req);

  		break;
  	}
  }

  static void skd_release_skreq(struct skd_device *skdev,
  			      struct skd_request_context *skreq)
  {

  	/*

  	 * Reclaim the skd_request_context
  	 */
  	skreq->state = SKD_REQ_STATE_IDLE;

  }

  static int skd_isr_completion_posted(struct skd_device *skdev,
  					int limit, int *enqueued)
  {

  	struct fit_completion_entry_v1 *skcmp;
  	struct fit_comp_error_info *skerr;

  	u16 req_id;

  	u32 tag;

  	u16 hwq = 0;

  	struct request *rq;

  	struct skd_request_context *skreq;

  	u16 cmp_cntxt;
  	u8 cmp_status;
  	u8 cmp_cycle;
  	u32 cmp_bytes;

  	int rc = 0;

  	int processed = 0;

  	lockdep_assert_held(&skdev->lock);

  	for (;; ) {
  		SKD_ASSERT(skdev->skcomp_ix < SKD_N_COMPLETION_ENTRY);
  
  		skcmp = &skdev->skcomp_table[skdev->skcomp_ix];
  		cmp_cycle = skcmp->cycle;
  		cmp_cntxt = skcmp->tag;
  		cmp_status = skcmp->status;
  		cmp_bytes = be32_to_cpu(skcmp->num_returned_bytes);
  
  		skerr = &skdev->skerr_table[skdev->skcomp_ix];

  		dev_dbg(&skdev->pdev->dev,
  			"cycle=%d ix=%d got cycle=%d cmdctxt=0x%x stat=%d busy=%d rbytes=0x%x proto=%d
  ",
  			skdev->skcomp_cycle, skdev->skcomp_ix, cmp_cycle,

  			cmp_cntxt, cmp_status, skd_in_flight(skdev),

  			cmp_bytes, skdev->proto_ver);

  
  		if (cmp_cycle != skdev->skcomp_cycle) {

  			dev_dbg(&skdev->pdev->dev, "end of completions
  ");

  			break;
  		}
  		/*
  		 * Update the completion queue head index and possibly
  		 * the completion cycle count. 8-bit wrap-around.
  		 */
  		skdev->skcomp_ix++;
  		if (skdev->skcomp_ix >= SKD_N_COMPLETION_ENTRY) {
  			skdev->skcomp_ix = 0;
  			skdev->skcomp_cycle++;
  		}
  
  		/*
  		 * The command context is a unique 32-bit ID. The low order
  		 * bits help locate the request. The request is usually a
  		 * r/w request (see skd_start() above) or a special request.
  		 */
  		req_id = cmp_cntxt;

  		tag = req_id & SKD_ID_SLOT_AND_TABLE_MASK;

  
  		/* Is this other than a r/w request? */

  		if (tag >= skdev->num_req_context) {

  			/*
  			 * This is not a completion for a r/w request.
  			 */

  			WARN_ON_ONCE(blk_mq_tag_to_rq(skdev->tag_set.tags[hwq],
  						      tag));

  			skd_complete_other(skdev, skcmp, skerr);
  			continue;
  		}

  		rq = blk_mq_tag_to_rq(skdev->tag_set.tags[hwq], tag);

  		if (WARN(!rq, "No request for tag %#x -> %#x
  ", cmp_cntxt,
  			 tag))
  			continue;

  		skreq = blk_mq_rq_to_pdu(rq);

  
  		/*
  		 * Make sure the request ID for the slot matches.
  		 */
  		if (skreq->id != req_id) {

  			dev_err(&skdev->pdev->dev,
  				"Completion mismatch comp_id=0x%04x skreq=0x%04x new=0x%04x
  ",
  				req_id, skreq->id, cmp_cntxt);

  			continue;

  		}
  
  		SKD_ASSERT(skreq->state == SKD_REQ_STATE_BUSY);

  		skreq->completion = *skcmp;
  		if (unlikely(cmp_status == SAM_STAT_CHECK_CONDITION)) {
  			skreq->err_info = *skerr;
  			skd_log_check_status(skdev, cmp_status, skerr->key,
  					     skerr->code, skerr->qual,
  					     skerr->fruc);
  		}
  		/* Release DMA resources for the request. */
  		if (skreq->n_sg > 0)
  			skd_postop_sg_list(skdev, skreq);

  		skd_release_skreq(skdev, skreq);

  
  		/*

  		 * Capture the outcome and post it back to the native request.

  		 */

  		if (likely(cmp_status == SAM_STAT_GOOD)) {
  			skreq->status = BLK_STS_OK;
  			blk_mq_complete_request(rq);
  		} else {

  			skd_resolve_req_exception(skdev, skreq, rq);

  		}

  
  		/* skd_isr_comp_limit equal zero means no limit */
  		if (limit) {
  			if (++processed >= limit) {
  				rc = 1;
  				break;
  			}
  		}
  	}

  	if (skdev->state == SKD_DRVR_STATE_PAUSING &&

  	    skd_in_flight(skdev) == 0) {

  		skdev->state = SKD_DRVR_STATE_PAUSED;
  		wake_up_interruptible(&skdev->waitq);
  	}
  
  	return rc;
  }
  
  static void skd_complete_other(struct skd_device *skdev,

  			       struct fit_completion_entry_v1 *skcomp,
  			       struct fit_comp_error_info *skerr)

  {
  	u32 req_id = 0;
  	u32 req_table;
  	u32 req_slot;
  	struct skd_special_context *skspcl;

  	lockdep_assert_held(&skdev->lock);

  	req_id = skcomp->tag;
  	req_table = req_id & SKD_ID_TABLE_MASK;
  	req_slot = req_id & SKD_ID_SLOT_MASK;

  	dev_dbg(&skdev->pdev->dev, "table=0x%x id=0x%x slot=%d
  ", req_table,
  		req_id, req_slot);

  
  	/*
  	 * Based on the request id, determine how to dispatch this completion.
  	 * This swich/case is finding the good cases and forwarding the
  	 * completion entry. Errors are reported below the switch.
  	 */
  	switch (req_table) {
  	case SKD_ID_RW_REQUEST:
  		/*

  		 * The caller, skd_isr_completion_posted() above,

  		 * handles r/w requests. The only way we get here
  		 * is if the req_slot is out of bounds.
  		 */
  		break;

  	case SKD_ID_INTERNAL:
  		if (req_slot == 0) {
  			skspcl = &skdev->internal_skspcl;
  			if (skspcl->req.id == req_id &&
  			    skspcl->req.state == SKD_REQ_STATE_BUSY) {
  				skd_complete_internal(skdev,
  						      skcomp, skerr, skspcl);
  				return;
  			}
  		}
  		break;
  
  	case SKD_ID_FIT_MSG:
  		/*
  		 * These id's should never appear in a completion record.
  		 */
  		break;
  
  	default:
  		/*
  		 * These id's should never appear anywhere;
  		 */
  		break;
  	}
  
  	/*
  	 * If we get here it is a bad or stale id.
  	 */
  }

  static void skd_reset_skcomp(struct skd_device *skdev)
  {

  	memset(skdev->skcomp_table, 0, SKD_SKCOMP_SIZE);

  
  	skdev->skcomp_ix = 0;
  	skdev->skcomp_cycle = 1;
  }
  
  /*
   *****************************************************************************
   * INTERRUPTS
   *****************************************************************************
   */
  static void skd_completion_worker(struct work_struct *work)
  {
  	struct skd_device *skdev =
  		container_of(work, struct skd_device, completion_worker);
  	unsigned long flags;
  	int flush_enqueued = 0;
  
  	spin_lock_irqsave(&skdev->lock, flags);
  
  	/*
  	 * pass in limit=0, which means no limit..
  	 * process everything in compq
  	 */
  	skd_isr_completion_posted(skdev, 0, &flush_enqueued);

  	schedule_work(&skdev->start_queue);

  
  	spin_unlock_irqrestore(&skdev->lock, flags);
  }
  
  static void skd_isr_msg_from_dev(struct skd_device *skdev);

  static irqreturn_t
  skd_isr(int irq, void *ptr)

  {

  	struct skd_device *skdev = ptr;

  	u32 intstat;
  	u32 ack;
  	int rc = 0;
  	int deferred = 0;
  	int flush_enqueued = 0;

  	spin_lock(&skdev->lock);
  
  	for (;; ) {
  		intstat = SKD_READL(skdev, FIT_INT_STATUS_HOST);
  
  		ack = FIT_INT_DEF_MASK;
  		ack &= intstat;

  		dev_dbg(&skdev->pdev->dev, "intstat=0x%x ack=0x%x
  ", intstat,
  			ack);

  
  		/* As long as there is an int pending on device, keep
  		 * running loop.  When none, get out, but if we've never
  		 * done any processing, call completion handler?
  		 */
  		if (ack == 0) {
  			/* No interrupts on device, but run the completion
  			 * processor anyway?
  			 */
  			if (rc == 0)
  				if (likely (skdev->state
  					== SKD_DRVR_STATE_ONLINE))
  					deferred = 1;
  			break;
  		}
  
  		rc = IRQ_HANDLED;
  
  		SKD_WRITEL(skdev, ack, FIT_INT_STATUS_HOST);
  
  		if (likely((skdev->state != SKD_DRVR_STATE_LOAD) &&
  			   (skdev->state != SKD_DRVR_STATE_STOPPING))) {
  			if (intstat & FIT_ISH_COMPLETION_POSTED) {
  				/*
  				 * If we have already deferred completion
  				 * processing, don't bother running it again
  				 */
  				if (deferred == 0)
  					deferred =
  						skd_isr_completion_posted(skdev,
  						skd_isr_comp_limit, &flush_enqueued);
  			}
  
  			if (intstat & FIT_ISH_FW_STATE_CHANGE) {
  				skd_isr_fwstate(skdev);
  				if (skdev->state == SKD_DRVR_STATE_FAULT ||
  				    skdev->state ==
  				    SKD_DRVR_STATE_DISAPPEARED) {
  					spin_unlock(&skdev->lock);
  					return rc;
  				}
  			}
  
  			if (intstat & FIT_ISH_MSG_FROM_DEV)
  				skd_isr_msg_from_dev(skdev);
  		}
  	}
  
  	if (unlikely(flush_enqueued))

  		schedule_work(&skdev->start_queue);

  
  	if (deferred)
  		schedule_work(&skdev->completion_worker);
  	else if (!flush_enqueued)

  		schedule_work(&skdev->start_queue);

  
  	spin_unlock(&skdev->lock);
  
  	return rc;
  }

  static void skd_drive_fault(struct skd_device *skdev)
  {
  	skdev->state = SKD_DRVR_STATE_FAULT;

  	dev_err(&skdev->pdev->dev, "Drive FAULT
  ");

  }
  
  static void skd_drive_disappeared(struct skd_device *skdev)
  {
  	skdev->state = SKD_DRVR_STATE_DISAPPEARED;

  	dev_err(&skdev->pdev->dev, "Drive DISAPPEARED
  ");

  }
  
  static void skd_isr_fwstate(struct skd_device *skdev)
  {
  	u32 sense;
  	u32 state;
  	u32 mtd;
  	int prev_driver_state = skdev->state;
  
  	sense = SKD_READL(skdev, FIT_STATUS);
  	state = sense & FIT_SR_DRIVE_STATE_MASK;

  	dev_err(&skdev->pdev->dev, "s1120 state %s(%d)=>%s(%d)
  ",
  		skd_drive_state_to_str(skdev->drive_state), skdev->drive_state,
  		skd_drive_state_to_str(state), state);

  
  	skdev->drive_state = state;
  
  	switch (skdev->drive_state) {
  	case FIT_SR_DRIVE_INIT:
  		if (skdev->state == SKD_DRVR_STATE_PROTOCOL_MISMATCH) {
  			skd_disable_interrupts(skdev);
  			break;
  		}
  		if (skdev->state == SKD_DRVR_STATE_RESTARTING)

  			skd_recover_requests(skdev);

  		if (skdev->state == SKD_DRVR_STATE_WAIT_BOOT) {
  			skdev->timer_countdown = SKD_STARTING_TIMO;
  			skdev->state = SKD_DRVR_STATE_STARTING;
  			skd_soft_reset(skdev);
  			break;
  		}
  		mtd = FIT_MXD_CONS(FIT_MTD_FITFW_INIT, 0, 0);
  		SKD_WRITEL(skdev, mtd, FIT_MSG_TO_DEVICE);
  		skdev->last_mtd = mtd;
  		break;
  
  	case FIT_SR_DRIVE_ONLINE:
  		skdev->cur_max_queue_depth = skd_max_queue_depth;
  		if (skdev->cur_max_queue_depth > skdev->dev_max_queue_depth)
  			skdev->cur_max_queue_depth = skdev->dev_max_queue_depth;
  
  		skdev->queue_low_water_mark =
  			skdev->cur_max_queue_depth * 2 / 3 + 1;
  		if (skdev->queue_low_water_mark < 1)
  			skdev->queue_low_water_mark = 1;

  		dev_info(&skdev->pdev->dev,
  			 "Queue depth limit=%d dev=%d lowat=%d
  ",
  			 skdev->cur_max_queue_depth,
  			 skdev->dev_max_queue_depth,
  			 skdev->queue_low_water_mark);

  
  		skd_refresh_device_data(skdev);
  		break;
  
  	case FIT_SR_DRIVE_BUSY:
  		skdev->state = SKD_DRVR_STATE_BUSY;
  		skdev->timer_countdown = SKD_BUSY_TIMO;
  		skd_quiesce_dev(skdev);
  		break;
  	case FIT_SR_DRIVE_BUSY_SANITIZE:
  		/* set timer for 3 seconds, we'll abort any unfinished
  		 * commands after that expires
  		 */
  		skdev->state = SKD_DRVR_STATE_BUSY_SANITIZE;
  		skdev->timer_countdown = SKD_TIMER_SECONDS(3);

  		schedule_work(&skdev->start_queue);

  		break;
  	case FIT_SR_DRIVE_BUSY_ERASE:
  		skdev->state = SKD_DRVR_STATE_BUSY_ERASE;
  		skdev->timer_countdown = SKD_BUSY_TIMO;
  		break;
  	case FIT_SR_DRIVE_OFFLINE:
  		skdev->state = SKD_DRVR_STATE_IDLE;
  		break;
  	case FIT_SR_DRIVE_SOFT_RESET:
  		switch (skdev->state) {
  		case SKD_DRVR_STATE_STARTING:
  		case SKD_DRVR_STATE_RESTARTING:
  			/* Expected by a caller of skd_soft_reset() */
  			break;
  		default:
  			skdev->state = SKD_DRVR_STATE_RESTARTING;
  			break;
  		}
  		break;
  	case FIT_SR_DRIVE_FW_BOOTING:

  		dev_dbg(&skdev->pdev->dev, "ISR FIT_SR_DRIVE_FW_BOOTING
  ");

  		skdev->state = SKD_DRVR_STATE_WAIT_BOOT;
  		skdev->timer_countdown = SKD_WAIT_BOOT_TIMO;
  		break;
  
  	case FIT_SR_DRIVE_DEGRADED:
  	case FIT_SR_PCIE_LINK_DOWN:
  	case FIT_SR_DRIVE_NEED_FW_DOWNLOAD:
  		break;
  
  	case FIT_SR_DRIVE_FAULT:
  		skd_drive_fault(skdev);

  		skd_recover_requests(skdev);

  		schedule_work(&skdev->start_queue);

  		break;
  
  	/* PCIe bus returned all Fs? */
  	case 0xFF:

  		dev_info(&skdev->pdev->dev, "state=0x%x sense=0x%x
  ", state,
  			 sense);

  		skd_drive_disappeared(skdev);

  		skd_recover_requests(skdev);

  		schedule_work(&skdev->start_queue);

  		break;
  	default:
  		/*
  		 * Uknown FW State. Wait for a state we recognize.
  		 */
  		break;
  	}

  	dev_err(&skdev->pdev->dev, "Driver state %s(%d)=>%s(%d)
  ",
  		skd_skdev_state_to_str(prev_driver_state), prev_driver_state,
  		skd_skdev_state_to_str(skdev->state), skdev->state);

  }

  static void skd_recover_request(struct request *req, void *data, bool reserved)

  {

  	struct skd_device *const skdev = data;
  	struct skd_request_context *skreq = blk_mq_rq_to_pdu(req);

  	if (skreq->state != SKD_REQ_STATE_BUSY)
  		return;

  	skd_log_skreq(skdev, skreq, "recover");

  	/* Release DMA resources for the request. */
  	if (skreq->n_sg > 0)
  		skd_postop_sg_list(skdev, skreq);

  	skreq->state = SKD_REQ_STATE_IDLE;

  	skreq->status = BLK_STS_IOERR;
  	blk_mq_complete_request(req);

  }

  static void skd_recover_requests(struct skd_device *skdev)
  {

  	blk_mq_tagset_busy_iter(&skdev->tag_set, skd_recover_request, skdev);

  }
  
  static void skd_isr_msg_from_dev(struct skd_device *skdev)
  {
  	u32 mfd;
  	u32 mtd;
  	u32 data;
  
  	mfd = SKD_READL(skdev, FIT_MSG_FROM_DEVICE);

  	dev_dbg(&skdev->pdev->dev, "mfd=0x%x last_mtd=0x%x
  ", mfd,
  		skdev->last_mtd);

  
  	/* ignore any mtd that is an ack for something we didn't send */
  	if (FIT_MXD_TYPE(mfd) != FIT_MXD_TYPE(skdev->last_mtd))
  		return;
  
  	switch (FIT_MXD_TYPE(mfd)) {
  	case FIT_MTD_FITFW_INIT:
  		skdev->proto_ver = FIT_PROTOCOL_MAJOR_VER(mfd);
  
  		if (skdev->proto_ver != FIT_PROTOCOL_VERSION_1) {

  			dev_err(&skdev->pdev->dev, "protocol mismatch
  ");
  			dev_err(&skdev->pdev->dev, "  got=%d support=%d
  ",
  				skdev->proto_ver, FIT_PROTOCOL_VERSION_1);
  			dev_err(&skdev->pdev->dev, "  please upgrade driver
  ");

  			skdev->state = SKD_DRVR_STATE_PROTOCOL_MISMATCH;
  			skd_soft_reset(skdev);
  			break;
  		}
  		mtd = FIT_MXD_CONS(FIT_MTD_GET_CMDQ_DEPTH, 0, 0);
  		SKD_WRITEL(skdev, mtd, FIT_MSG_TO_DEVICE);
  		skdev->last_mtd = mtd;
  		break;
  
  	case FIT_MTD_GET_CMDQ_DEPTH:
  		skdev->dev_max_queue_depth = FIT_MXD_DATA(mfd);
  		mtd = FIT_MXD_CONS(FIT_MTD_SET_COMPQ_DEPTH, 0,
  				   SKD_N_COMPLETION_ENTRY);
  		SKD_WRITEL(skdev, mtd, FIT_MSG_TO_DEVICE);
  		skdev->last_mtd = mtd;
  		break;
  
  	case FIT_MTD_SET_COMPQ_DEPTH:
  		SKD_WRITEQ(skdev, skdev->cq_dma_address, FIT_MSG_TO_DEVICE_ARG);
  		mtd = FIT_MXD_CONS(FIT_MTD_SET_COMPQ_ADDR, 0, 0);
  		SKD_WRITEL(skdev, mtd, FIT_MSG_TO_DEVICE);
  		skdev->last_mtd = mtd;
  		break;
  
  	case FIT_MTD_SET_COMPQ_ADDR:
  		skd_reset_skcomp(skdev);
  		mtd = FIT_MXD_CONS(FIT_MTD_CMD_LOG_HOST_ID, 0, skdev->devno);
  		SKD_WRITEL(skdev, mtd, FIT_MSG_TO_DEVICE);
  		skdev->last_mtd = mtd;
  		break;
  
  	case FIT_MTD_CMD_LOG_HOST_ID:
  		skdev->connect_time_stamp = get_seconds();
  		data = skdev->connect_time_stamp & 0xFFFF;
  		mtd = FIT_MXD_CONS(FIT_MTD_CMD_LOG_TIME_STAMP_LO, 0, data);
  		SKD_WRITEL(skdev, mtd, FIT_MSG_TO_DEVICE);
  		skdev->last_mtd = mtd;
  		break;
  
  	case FIT_MTD_CMD_LOG_TIME_STAMP_LO:
  		skdev->drive_jiffies = FIT_MXD_DATA(mfd);
  		data = (skdev->connect_time_stamp >> 16) & 0xFFFF;
  		mtd = FIT_MXD_CONS(FIT_MTD_CMD_LOG_TIME_STAMP_HI, 0, data);
  		SKD_WRITEL(skdev, mtd, FIT_MSG_TO_DEVICE);
  		skdev->last_mtd = mtd;
  		break;
  
  	case FIT_MTD_CMD_LOG_TIME_STAMP_HI:
  		skdev->drive_jiffies |= (FIT_MXD_DATA(mfd) << 16);
  		mtd = FIT_MXD_CONS(FIT_MTD_ARM_QUEUE, 0, 0);
  		SKD_WRITEL(skdev, mtd, FIT_MSG_TO_DEVICE);
  		skdev->last_mtd = mtd;

  		dev_err(&skdev->pdev->dev, "Time sync driver=0x%x device=0x%x
  ",
  			skdev->connect_time_stamp, skdev->drive_jiffies);

  		break;
  
  	case FIT_MTD_ARM_QUEUE:
  		skdev->last_mtd = 0;
  		/*
  		 * State should be, or soon will be, FIT_SR_DRIVE_ONLINE.
  		 */
  		break;
  
  	default:
  		break;
  	}
  }
  
  static void skd_disable_interrupts(struct skd_device *skdev)
  {
  	u32 sense;
  
  	sense = SKD_READL(skdev, FIT_CONTROL);
  	sense &= ~FIT_CR_ENABLE_INTERRUPTS;
  	SKD_WRITEL(skdev, sense, FIT_CONTROL);

  	dev_dbg(&skdev->pdev->dev, "sense 0x%x
  ", sense);

  
  	/* Note that the 1s is written. A 1-bit means
  	 * disable, a 0 means enable.
  	 */
  	SKD_WRITEL(skdev, ~0, FIT_INT_MASK_HOST);
  }
  
  static void skd_enable_interrupts(struct skd_device *skdev)
  {
  	u32 val;
  
  	/* unmask interrupts first */
  	val = FIT_ISH_FW_STATE_CHANGE +
  	      FIT_ISH_COMPLETION_POSTED + FIT_ISH_MSG_FROM_DEV;
  
  	/* Note that the compliment of mask is written. A 1-bit means
  	 * disable, a 0 means enable. */
  	SKD_WRITEL(skdev, ~val, FIT_INT_MASK_HOST);

  	dev_dbg(&skdev->pdev->dev, "interrupt mask=0x%x
  ", ~val);

  
  	val = SKD_READL(skdev, FIT_CONTROL);
  	val |= FIT_CR_ENABLE_INTERRUPTS;

  	dev_dbg(&skdev->pdev->dev, "control=0x%x
  ", val);

  	SKD_WRITEL(skdev, val, FIT_CONTROL);
  }
  
  /*
   *****************************************************************************
   * START, STOP, RESTART, QUIESCE, UNQUIESCE
   *****************************************************************************
   */
  
  static void skd_soft_reset(struct skd_device *skdev)
  {
  	u32 val;
  
  	val = SKD_READL(skdev, FIT_CONTROL);
  	val |= (FIT_CR_SOFT_RESET);

  	dev_dbg(&skdev->pdev->dev, "control=0x%x
  ", val);

  	SKD_WRITEL(skdev, val, FIT_CONTROL);
  }
  
  static void skd_start_device(struct skd_device *skdev)
  {
  	unsigned long flags;
  	u32 sense;
  	u32 state;
  
  	spin_lock_irqsave(&skdev->lock, flags);
  
  	/* ack all ghost interrupts */
  	SKD_WRITEL(skdev, FIT_INT_DEF_MASK, FIT_INT_STATUS_HOST);
  
  	sense = SKD_READL(skdev, FIT_STATUS);

  	dev_dbg(&skdev->pdev->dev, "initial status=0x%x
  ", sense);

  
  	state = sense & FIT_SR_DRIVE_STATE_MASK;
  	skdev->drive_state = state;
  	skdev->last_mtd = 0;
  
  	skdev->state = SKD_DRVR_STATE_STARTING;
  	skdev->timer_countdown = SKD_STARTING_TIMO;
  
  	skd_enable_interrupts(skdev);
  
  	switch (skdev->drive_state) {
  	case FIT_SR_DRIVE_OFFLINE:

  		dev_err(&skdev->pdev->dev, "Drive offline...
  ");

  		break;
  
  	case FIT_SR_DRIVE_FW_BOOTING:

  		dev_dbg(&skdev->pdev->dev, "FIT_SR_DRIVE_FW_BOOTING
  ");

  		skdev->state = SKD_DRVR_STATE_WAIT_BOOT;
  		skdev->timer_countdown = SKD_WAIT_BOOT_TIMO;
  		break;
  
  	case FIT_SR_DRIVE_BUSY_SANITIZE:

  		dev_info(&skdev->pdev->dev, "Start: BUSY_SANITIZE
  ");

  		skdev->state = SKD_DRVR_STATE_BUSY_SANITIZE;
  		skdev->timer_countdown = SKD_STARTED_BUSY_TIMO;
  		break;
  
  	case FIT_SR_DRIVE_BUSY_ERASE:

  		dev_info(&skdev->pdev->dev, "Start: BUSY_ERASE
  ");

  		skdev->state = SKD_DRVR_STATE_BUSY_ERASE;
  		skdev->timer_countdown = SKD_STARTED_BUSY_TIMO;
  		break;
  
  	case FIT_SR_DRIVE_INIT:
  	case FIT_SR_DRIVE_ONLINE:
  		skd_soft_reset(skdev);
  		break;
  
  	case FIT_SR_DRIVE_BUSY:

  		dev_err(&skdev->pdev->dev, "Drive Busy...
  ");

  		skdev->state = SKD_DRVR_STATE_BUSY;
  		skdev->timer_countdown = SKD_STARTED_BUSY_TIMO;
  		break;
  
  	case FIT_SR_DRIVE_SOFT_RESET:

  		dev_err(&skdev->pdev->dev, "drive soft reset in prog
  ");

  		break;
  
  	case FIT_SR_DRIVE_FAULT:
  		/* Fault state is bad...soft reset won't do it...
  		 * Hard reset, maybe, but does it work on device?
  		 * For now, just fault so the system doesn't hang.
  		 */
  		skd_drive_fault(skdev);
  		/*start the queue so we can respond with error to requests */

  		dev_dbg(&skdev->pdev->dev, "starting queue
  ");

  		schedule_work(&skdev->start_queue);

  		skdev->gendisk_on = -1;
  		wake_up_interruptible(&skdev->waitq);
  		break;
  
  	case 0xFF:
  		/* Most likely the device isn't there or isn't responding
  		 * to the BAR1 addresses. */
  		skd_drive_disappeared(skdev);
  		/*start the queue so we can respond with error to requests */

  		dev_dbg(&skdev->pdev->dev,
  			"starting queue to error-out reqs
  ");

  		schedule_work(&skdev->start_queue);

  		skdev->gendisk_on = -1;
  		wake_up_interruptible(&skdev->waitq);
  		break;
  
  	default:

  		dev_err(&skdev->pdev->dev, "Start: unknown state %x
  ",
  			skdev->drive_state);

  		break;
  	}
  
  	state = SKD_READL(skdev, FIT_CONTROL);

  	dev_dbg(&skdev->pdev->dev, "FIT Control Status=0x%x
  ", state);

  
  	state = SKD_READL(skdev, FIT_INT_STATUS_HOST);

  	dev_dbg(&skdev->pdev->dev, "Intr Status=0x%x
  ", state);

  
  	state = SKD_READL(skdev, FIT_INT_MASK_HOST);

  	dev_dbg(&skdev->pdev->dev, "Intr Mask=0x%x
  ", state);

  
  	state = SKD_READL(skdev, FIT_MSG_FROM_DEVICE);

  	dev_dbg(&skdev->pdev->dev, "Msg from Dev=0x%x
  ", state);

  
  	state = SKD_READL(skdev, FIT_HW_VERSION);

  	dev_dbg(&skdev->pdev->dev, "HW version=0x%x
  ", state);

  
  	spin_unlock_irqrestore(&skdev->lock, flags);
  }
  
  static void skd_stop_device(struct skd_device *skdev)
  {
  	unsigned long flags;
  	struct skd_special_context *skspcl = &skdev->internal_skspcl;
  	u32 dev_state;
  	int i;
  
  	spin_lock_irqsave(&skdev->lock, flags);
  
  	if (skdev->state != SKD_DRVR_STATE_ONLINE) {

  		dev_err(&skdev->pdev->dev, "%s not online no sync
  ", __func__);

  		goto stop_out;
  	}
  
  	if (skspcl->req.state != SKD_REQ_STATE_IDLE) {

  		dev_err(&skdev->pdev->dev, "%s no special
  ", __func__);

  		goto stop_out;
  	}
  
  	skdev->state = SKD_DRVR_STATE_SYNCING;
  	skdev->sync_done = 0;
  
  	skd_send_internal_skspcl(skdev, skspcl, SYNCHRONIZE_CACHE);
  
  	spin_unlock_irqrestore(&skdev->lock, flags);
  
  	wait_event_interruptible_timeout(skdev->waitq,
  					 (skdev->sync_done), (10 * HZ));
  
  	spin_lock_irqsave(&skdev->lock, flags);
  
  	switch (skdev->sync_done) {
  	case 0:

  		dev_err(&skdev->pdev->dev, "%s no sync
  ", __func__);

  		break;
  	case 1:

  		dev_err(&skdev->pdev->dev, "%s sync done
  ", __func__);

  		break;
  	default:

  		dev_err(&skdev->pdev->dev, "%s sync error
  ", __func__);

  	}
  
  stop_out:
  	skdev->state = SKD_DRVR_STATE_STOPPING;
  	spin_unlock_irqrestore(&skdev->lock, flags);
  
  	skd_kill_timer(skdev);
  
  	spin_lock_irqsave(&skdev->lock, flags);
  	skd_disable_interrupts(skdev);
  
  	/* ensure all ints on device are cleared */
  	/* soft reset the device to unload with a clean slate */
  	SKD_WRITEL(skdev, FIT_INT_DEF_MASK, FIT_INT_STATUS_HOST);
  	SKD_WRITEL(skdev, FIT_CR_SOFT_RESET, FIT_CONTROL);
  
  	spin_unlock_irqrestore(&skdev->lock, flags);
  
  	/* poll every 100ms, 1 second timeout */
  	for (i = 0; i < 10; i++) {
  		dev_state =
  			SKD_READL(skdev, FIT_STATUS) & FIT_SR_DRIVE_STATE_MASK;
  		if (dev_state == FIT_SR_DRIVE_INIT)
  			break;
  		set_current_state(TASK_INTERRUPTIBLE);
  		schedule_timeout(msecs_to_jiffies(100));
  	}
  
  	if (dev_state != FIT_SR_DRIVE_INIT)

  		dev_err(&skdev->pdev->dev, "%s state error 0x%02x
  ", __func__,
  			dev_state);

  }
  
  /* assume spinlock is held */
  static void skd_restart_device(struct skd_device *skdev)
  {
  	u32 state;
  
  	/* ack all ghost interrupts */
  	SKD_WRITEL(skdev, FIT_INT_DEF_MASK, FIT_INT_STATUS_HOST);
  
  	state = SKD_READL(skdev, FIT_STATUS);

  	dev_dbg(&skdev->pdev->dev, "drive status=0x%x
  ", state);

  
  	state &= FIT_SR_DRIVE_STATE_MASK;
  	skdev->drive_state = state;
  	skdev->last_mtd = 0;
  
  	skdev->state = SKD_DRVR_STATE_RESTARTING;
  	skdev->timer_countdown = SKD_RESTARTING_TIMO;
  
  	skd_soft_reset(skdev);
  }
  
  /* assume spinlock is held */
  static int skd_quiesce_dev(struct skd_device *skdev)
  {
  	int rc = 0;
  
  	switch (skdev->state) {
  	case SKD_DRVR_STATE_BUSY:
  	case SKD_DRVR_STATE_BUSY_IMMINENT:

  		dev_dbg(&skdev->pdev->dev, "stopping queue
  ");

  		blk_mq_stop_hw_queues(skdev->queue);

  		break;
  	case SKD_DRVR_STATE_ONLINE:
  	case SKD_DRVR_STATE_STOPPING:
  	case SKD_DRVR_STATE_SYNCING:
  	case SKD_DRVR_STATE_PAUSING:
  	case SKD_DRVR_STATE_PAUSED:
  	case SKD_DRVR_STATE_STARTING:
  	case SKD_DRVR_STATE_RESTARTING:
  	case SKD_DRVR_STATE_RESUMING:
  	default:
  		rc = -EINVAL;

  		dev_dbg(&skdev->pdev->dev, "state [%d] not implemented
  ",
  			skdev->state);

  	}
  	return rc;
  }
  
  /* assume spinlock is held */
  static int skd_unquiesce_dev(struct skd_device *skdev)
  {
  	int prev_driver_state = skdev->state;
  
  	skd_log_skdev(skdev, "unquiesce");
  	if (skdev->state == SKD_DRVR_STATE_ONLINE) {

  		dev_dbg(&skdev->pdev->dev, "**** device already ONLINE
  ");

  		return 0;
  	}
  	if (skdev->drive_state != FIT_SR_DRIVE_ONLINE) {
  		/*
  		 * If there has been an state change to other than
  		 * ONLINE, we will rely on controller state change
  		 * to come back online and restart the queue.
  		 * The BUSY state means that driver is ready to
  		 * continue normal processing but waiting for controller
  		 * to become available.
  		 */
  		skdev->state = SKD_DRVR_STATE_BUSY;

  		dev_dbg(&skdev->pdev->dev, "drive BUSY state
  ");

  		return 0;
  	}
  
  	/*
  	 * Drive has just come online, driver is either in startup,
  	 * paused performing a task, or bust waiting for hardware.
  	 */
  	switch (skdev->state) {
  	case SKD_DRVR_STATE_PAUSED:
  	case SKD_DRVR_STATE_BUSY:
  	case SKD_DRVR_STATE_BUSY_IMMINENT:
  	case SKD_DRVR_STATE_BUSY_ERASE:
  	case SKD_DRVR_STATE_STARTING:
  	case SKD_DRVR_STATE_RESTARTING:
  	case SKD_DRVR_STATE_FAULT:
  	case SKD_DRVR_STATE_IDLE:
  	case SKD_DRVR_STATE_LOAD:
  		skdev->state = SKD_DRVR_STATE_ONLINE;

  		dev_err(&skdev->pdev->dev, "Driver state %s(%d)=>%s(%d)
  ",
  			skd_skdev_state_to_str(prev_driver_state),
  			prev_driver_state, skd_skdev_state_to_str(skdev->state),
  			skdev->state);
  		dev_dbg(&skdev->pdev->dev,
  			"**** device ONLINE...starting block queue
  ");
  		dev_dbg(&skdev->pdev->dev, "starting queue
  ");
  		dev_info(&skdev->pdev->dev, "STEC s1120 ONLINE
  ");

  		schedule_work(&skdev->start_queue);

  		skdev->gendisk_on = 1;
  		wake_up_interruptible(&skdev->waitq);
  		break;
  
  	case SKD_DRVR_STATE_DISAPPEARED:
  	default:

  		dev_dbg(&skdev->pdev->dev,
  			"**** driver state %d, not implemented
  ",
  			skdev->state);

  		return -EBUSY;
  	}
  	return 0;
  }
  
  /*
   *****************************************************************************
   * PCIe MSI/MSI-X INTERRUPT HANDLERS
   *****************************************************************************
   */
  
  static irqreturn_t skd_reserved_isr(int irq, void *skd_host_data)
  {
  	struct skd_device *skdev = skd_host_data;
  	unsigned long flags;
  
  	spin_lock_irqsave(&skdev->lock, flags);

  	dev_dbg(&skdev->pdev->dev, "MSIX = 0x%x
  ",
  		SKD_READL(skdev, FIT_INT_STATUS_HOST));
  	dev_err(&skdev->pdev->dev, "MSIX reserved irq %d = 0x%x
  ", irq,
  		SKD_READL(skdev, FIT_INT_STATUS_HOST));

  	SKD_WRITEL(skdev, FIT_INT_RESERVED_MASK, FIT_INT_STATUS_HOST);
  	spin_unlock_irqrestore(&skdev->lock, flags);
  	return IRQ_HANDLED;
  }
  
  static irqreturn_t skd_statec_isr(int irq, void *skd_host_data)
  {
  	struct skd_device *skdev = skd_host_data;
  	unsigned long flags;
  
  	spin_lock_irqsave(&skdev->lock, flags);

  	dev_dbg(&skdev->pdev->dev, "MSIX = 0x%x
  ",
  		SKD_READL(skdev, FIT_INT_STATUS_HOST));

  	SKD_WRITEL(skdev, FIT_ISH_FW_STATE_CHANGE, FIT_INT_STATUS_HOST);
  	skd_isr_fwstate(skdev);
  	spin_unlock_irqrestore(&skdev->lock, flags);
  	return IRQ_HANDLED;
  }
  
  static irqreturn_t skd_comp_q(int irq, void *skd_host_data)
  {
  	struct skd_device *skdev = skd_host_data;
  	unsigned long flags;
  	int flush_enqueued = 0;
  	int deferred;
  
  	spin_lock_irqsave(&skdev->lock, flags);

  	dev_dbg(&skdev->pdev->dev, "MSIX = 0x%x
  ",
  		SKD_READL(skdev, FIT_INT_STATUS_HOST));

  	SKD_WRITEL(skdev, FIT_ISH_COMPLETION_POSTED, FIT_INT_STATUS_HOST);
  	deferred = skd_isr_completion_posted(skdev, skd_isr_comp_limit,
  						&flush_enqueued);

  	if (flush_enqueued)

  		schedule_work(&skdev->start_queue);

  
  	if (deferred)
  		schedule_work(&skdev->completion_worker);
  	else if (!flush_enqueued)

  		schedule_work(&skdev->start_queue);

  
  	spin_unlock_irqrestore(&skdev->lock, flags);
  
  	return IRQ_HANDLED;
  }
  
  static irqreturn_t skd_msg_isr(int irq, void *skd_host_data)
  {
  	struct skd_device *skdev = skd_host_data;
  	unsigned long flags;
  
  	spin_lock_irqsave(&skdev->lock, flags);

  	dev_dbg(&skdev->pdev->dev, "MSIX = 0x%x
  ",
  		SKD_READL(skdev, FIT_INT_STATUS_HOST));

  	SKD_WRITEL(skdev, FIT_ISH_MSG_FROM_DEV, FIT_INT_STATUS_HOST);
  	skd_isr_msg_from_dev(skdev);
  	spin_unlock_irqrestore(&skdev->lock, flags);
  	return IRQ_HANDLED;
  }
  
  static irqreturn_t skd_qfull_isr(int irq, void *skd_host_data)
  {
  	struct skd_device *skdev = skd_host_data;
  	unsigned long flags;
  
  	spin_lock_irqsave(&skdev->lock, flags);

  	dev_dbg(&skdev->pdev->dev, "MSIX = 0x%x
  ",
  		SKD_READL(skdev, FIT_INT_STATUS_HOST));

  	SKD_WRITEL(skdev, FIT_INT_QUEUE_FULL, FIT_INT_STATUS_HOST);
  	spin_unlock_irqrestore(&skdev->lock, flags);
  	return IRQ_HANDLED;
  }
  
  /*
   *****************************************************************************
   * PCIe MSI/MSI-X SETUP
   *****************************************************************************
   */
  
  struct skd_msix_entry {

  	char isr_name[30];
  };
  
  struct skd_init_msix_entry {
  	const char *name;
  	irq_handler_t handler;
  };
  
  #define SKD_MAX_MSIX_COUNT              13
  #define SKD_MIN_MSIX_COUNT              7
  #define SKD_BASE_MSIX_IRQ               4
  
  static struct skd_init_msix_entry msix_entries[SKD_MAX_MSIX_COUNT] = {
  	{ "(DMA 0)",	    skd_reserved_isr },
  	{ "(DMA 1)",	    skd_reserved_isr },
  	{ "(DMA 2)",	    skd_reserved_isr },
  	{ "(DMA 3)",	    skd_reserved_isr },
  	{ "(State Change)", skd_statec_isr   },
  	{ "(COMPL_Q)",	    skd_comp_q	     },
  	{ "(MSG)",	    skd_msg_isr	     },
  	{ "(Reserved)",	    skd_reserved_isr },
  	{ "(Reserved)",	    skd_reserved_isr },
  	{ "(Queue Full 0)", skd_qfull_isr    },
  	{ "(Queue Full 1)", skd_qfull_isr    },
  	{ "(Queue Full 2)", skd_qfull_isr    },
  	{ "(Queue Full 3)", skd_qfull_isr    },
  };

  static int skd_acquire_msix(struct skd_device *skdev)
  {

  	int i, rc;

  	struct pci_dev *pdev = skdev->pdev;

  	rc = pci_alloc_irq_vectors(pdev, SKD_MAX_MSIX_COUNT, SKD_MAX_MSIX_COUNT,
  			PCI_IRQ_MSIX);
  	if (rc < 0) {

  		dev_err(&skdev->pdev->dev, "failed to enable MSI-X %d
  ", rc);

  		goto out;

  	}

  	skdev->msix_entries = kcalloc(SKD_MAX_MSIX_COUNT,
  			sizeof(struct skd_msix_entry), GFP_KERNEL);

  	if (!skdev->msix_entries) {
  		rc = -ENOMEM;

  		dev_err(&skdev->pdev->dev, "msix table allocation error
  ");

  		goto out;

  	}

  	/* Enable MSI-X vectors for the base queue */

  	for (i = 0; i < SKD_MAX_MSIX_COUNT; i++) {
  		struct skd_msix_entry *qentry = &skdev->msix_entries[i];

  		snprintf(qentry->isr_name, sizeof(qentry->isr_name),
  			 "%s%d-msix %s", DRV_NAME, skdev->devno,
  			 msix_entries[i].name);

  
  		rc = devm_request_irq(&skdev->pdev->dev,
  				pci_irq_vector(skdev->pdev, i),
  				msix_entries[i].handler, 0,
  				qentry->isr_name, skdev);

  		if (rc) {

  			dev_err(&skdev->pdev->dev,
  				"Unable to register(%d) MSI-X handler %d: %s
  ",
  				rc, i, qentry->isr_name);

  			goto msix_out;

  		}
  	}

  	dev_dbg(&skdev->pdev->dev, "%d msix irq(s) enabled
  ",
  		SKD_MAX_MSIX_COUNT);

  	return 0;
  
  msix_out:

  	while (--i >= 0)
  		devm_free_irq(&pdev->dev, pci_irq_vector(pdev, i), skdev);

  out:

  	kfree(skdev->msix_entries);
  	skdev->msix_entries = NULL;

  	return rc;
  }
  
  static int skd_acquire_irq(struct skd_device *skdev)
  {

  	struct pci_dev *pdev = skdev->pdev;
  	unsigned int irq_flag = PCI_IRQ_LEGACY;

  	int rc;

  	if (skd_isr_type == SKD_IRQ_MSIX) {

  		rc = skd_acquire_msix(skdev);
  		if (!rc)

  			return 0;

  		dev_err(&skdev->pdev->dev,
  			"failed to enable MSI-X, re-trying with MSI %d
  ", rc);

  	}

  
  	snprintf(skdev->isr_name, sizeof(skdev->isr_name), "%s%d", DRV_NAME,
  			skdev->devno);
  
  	if (skd_isr_type != SKD_IRQ_LEGACY)
  		irq_flag |= PCI_IRQ_MSI;
  	rc = pci_alloc_irq_vectors(pdev, 1, 1, irq_flag);
  	if (rc < 0) {

  		dev_err(&skdev->pdev->dev,
  			"failed to allocate the MSI interrupt %d
  ", rc);

  		return rc;
  	}
  
  	rc = devm_request_irq(&pdev->dev, pdev->irq, skd_isr,
  			pdev->msi_enabled ? 0 : IRQF_SHARED,
  			skdev->isr_name, skdev);
  	if (rc) {
  		pci_free_irq_vectors(pdev);

  		dev_err(&skdev->pdev->dev, "failed to allocate interrupt %d
  ",
  			rc);

  		return rc;
  	}
  
  	return 0;

  }
  
  static void skd_release_irq(struct skd_device *skdev)
  {

  	struct pci_dev *pdev = skdev->pdev;
  
  	if (skdev->msix_entries) {
  		int i;
  
  		for (i = 0; i < SKD_MAX_MSIX_COUNT; i++) {
  			devm_free_irq(&pdev->dev, pci_irq_vector(pdev, i),
  					skdev);
  		}
  
  		kfree(skdev->msix_entries);
  		skdev->msix_entries = NULL;
  	} else {
  		devm_free_irq(&pdev->dev, pdev->irq, skdev);

  	}

  
  	pci_free_irq_vectors(pdev);

  }
  
  /*
   *****************************************************************************
   * CONSTRUCT
   *****************************************************************************
   */

  static void *skd_alloc_dma(struct skd_device *skdev, struct kmem_cache *s,
  			   dma_addr_t *dma_handle, gfp_t gfp,
  			   enum dma_data_direction dir)
  {
  	struct device *dev = &skdev->pdev->dev;
  	void *buf;
  
  	buf = kmem_cache_alloc(s, gfp);
  	if (!buf)
  		return NULL;
  	*dma_handle = dma_map_single(dev, buf, s->size, dir);
  	if (dma_mapping_error(dev, *dma_handle)) {

  		kmem_cache_free(s, buf);

  		buf = NULL;
  	}
  	return buf;
  }
  
  static void skd_free_dma(struct skd_device *skdev, struct kmem_cache *s,
  			 void *vaddr, dma_addr_t dma_handle,
  			 enum dma_data_direction dir)
  {
  	if (!vaddr)
  		return;
  
  	dma_unmap_single(&skdev->pdev->dev, dma_handle, s->size, dir);
  	kmem_cache_free(s, vaddr);
  }

  static int skd_cons_skcomp(struct skd_device *skdev)
  {
  	int rc = 0;
  	struct fit_completion_entry_v1 *skcomp;

  	dev_dbg(&skdev->pdev->dev,

  		"comp pci_alloc, total bytes %zd entries %d
  ",
  		SKD_SKCOMP_SIZE, SKD_N_COMPLETION_ENTRY);

  	skcomp = pci_zalloc_consistent(skdev->pdev, SKD_SKCOMP_SIZE,

  				       &skdev->cq_dma_address);

  
  	if (skcomp == NULL) {
  		rc = -ENOMEM;
  		goto err_out;
  	}

  	skdev->skcomp_table = skcomp;
  	skdev->skerr_table = (struct fit_comp_error_info *)((char *)skcomp +
  							   sizeof(*skcomp) *
  							   SKD_N_COMPLETION_ENTRY);
  
  err_out:
  	return rc;
  }
  
  static int skd_cons_skmsg(struct skd_device *skdev)
  {
  	int rc = 0;
  	u32 i;

  	dev_dbg(&skdev->pdev->dev,

  		"skmsg_table kcalloc, struct %lu, count %u total %lu
  ",

  		sizeof(struct skd_fitmsg_context), skdev->num_fitmsg_context,
  		sizeof(struct skd_fitmsg_context) * skdev->num_fitmsg_context);

  	skdev->skmsg_table = kcalloc(skdev->num_fitmsg_context,
  				     sizeof(struct skd_fitmsg_context),
  				     GFP_KERNEL);

  	if (skdev->skmsg_table == NULL) {
  		rc = -ENOMEM;
  		goto err_out;
  	}
  
  	for (i = 0; i < skdev->num_fitmsg_context; i++) {
  		struct skd_fitmsg_context *skmsg;
  
  		skmsg = &skdev->skmsg_table[i];
  
  		skmsg->id = i + SKD_ID_FIT_MSG;

  		skmsg->msg_buf = pci_alloc_consistent(skdev->pdev,

  						      SKD_N_FITMSG_BYTES,

  						      &skmsg->mb_dma_address);
  
  		if (skmsg->msg_buf == NULL) {
  			rc = -ENOMEM;
  			goto err_out;
  		}

  		WARN(((uintptr_t)skmsg->msg_buf | skmsg->mb_dma_address) &
  		     (FIT_QCMD_ALIGN - 1),
  		     "not aligned: msg_buf %p mb_dma_address %#llx
  ",
  		     skmsg->msg_buf, skmsg->mb_dma_address);

  		memset(skmsg->msg_buf, 0, SKD_N_FITMSG_BYTES);

  	}

  err_out:
  	return rc;
  }

  static struct fit_sg_descriptor *skd_cons_sg_list(struct skd_device *skdev,
  						  u32 n_sg,
  						  dma_addr_t *ret_dma_addr)
  {
  	struct fit_sg_descriptor *sg_list;

  	sg_list = skd_alloc_dma(skdev, skdev->sglist_cache, ret_dma_addr,
  				GFP_DMA | __GFP_ZERO, DMA_TO_DEVICE);

  
  	if (sg_list != NULL) {
  		uint64_t dma_address = *ret_dma_addr;
  		u32 i;

  		for (i = 0; i < n_sg - 1; i++) {
  			uint64_t ndp_off;
  			ndp_off = (i + 1) * sizeof(struct fit_sg_descriptor);
  
  			sg_list[i].next_desc_ptr = dma_address + ndp_off;
  		}
  		sg_list[i].next_desc_ptr = 0LL;
  	}
  
  	return sg_list;
  }

  static void skd_free_sg_list(struct skd_device *skdev,

  			     struct fit_sg_descriptor *sg_list,

  			     dma_addr_t dma_addr)
  {

  	if (WARN_ON_ONCE(!sg_list))
  		return;

  	skd_free_dma(skdev, skdev->sglist_cache, sg_list, dma_addr,
  		     DMA_TO_DEVICE);

  }

  static int skd_init_request(struct blk_mq_tag_set *set, struct request *rq,
  			    unsigned int hctx_idx, unsigned int numa_node)

  {

  	struct skd_device *skdev = set->driver_data;

  	struct skd_request_context *skreq = blk_mq_rq_to_pdu(rq);

  	skreq->state = SKD_REQ_STATE_IDLE;
  	skreq->sg = (void *)(skreq + 1);
  	sg_init_table(skreq->sg, skd_sgs_per_request);
  	skreq->sksg_list = skd_cons_sg_list(skdev, skd_sgs_per_request,
  					    &skreq->sksg_dma_address);

  	return skreq->sksg_list ? 0 : -ENOMEM;
  }

  static void skd_exit_request(struct blk_mq_tag_set *set, struct request *rq,
  			     unsigned int hctx_idx)

  {

  	struct skd_device *skdev = set->driver_data;

  	struct skd_request_context *skreq = blk_mq_rq_to_pdu(rq);

  	skd_free_sg_list(skdev, skreq->sksg_list, skreq->sksg_dma_address);

  }

  static int skd_cons_sksb(struct skd_device *skdev)
  {
  	int rc = 0;
  	struct skd_special_context *skspcl;

  
  	skspcl = &skdev->internal_skspcl;
  
  	skspcl->req.id = 0 + SKD_ID_INTERNAL;
  	skspcl->req.state = SKD_REQ_STATE_IDLE;

  	skspcl->data_buf = skd_alloc_dma(skdev, skdev->databuf_cache,
  					 &skspcl->db_dma_address,
  					 GFP_DMA | __GFP_ZERO,
  					 DMA_BIDIRECTIONAL);

  	if (skspcl->data_buf == NULL) {
  		rc = -ENOMEM;
  		goto err_out;
  	}

  	skspcl->msg_buf = skd_alloc_dma(skdev, skdev->msgbuf_cache,
  					&skspcl->mb_dma_address,
  					GFP_DMA | __GFP_ZERO, DMA_TO_DEVICE);

  	if (skspcl->msg_buf == NULL) {
  		rc = -ENOMEM;
  		goto err_out;
  	}

  	skspcl->req.sksg_list = skd_cons_sg_list(skdev, 1,
  						 &skspcl->req.sksg_dma_address);
  	if (skspcl->req.sksg_list == NULL) {
  		rc = -ENOMEM;
  		goto err_out;
  	}
  
  	if (!skd_format_internal_skspcl(skdev)) {
  		rc = -EINVAL;
  		goto err_out;
  	}
  
  err_out:
  	return rc;
  }

  static const struct blk_mq_ops skd_mq_ops = {
  	.queue_rq	= skd_mq_queue_rq,