/*-
 * Copyright (c) 2017 Broadcom. All rights reserved.
 * The term "Broadcom" refers to Broadcom Limited and/or its subsidiaries.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * 3. Neither the name of the copyright holder nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/**
 * @file
 * OCS Linux SCSI API base driver implementation.
 */

/**
 * @defgroup scsi_api_base SCSI Base Target/Initiator
 */

#include "ocs.h"
#include "ocs_els.h"
#include "ocs_scsi.h"
#include "ocs_vpd.h"
#include "ocs_utils.h"
#include "ocs_device.h"

#define SCSI_IOFMT "[%04x][i:%0*x t:%0*x h:%04x]"
#define SCSI_ITT_SIZE(ocs)      ((ocs->ocs_xport == OCS_XPORT_FC) ? 4 : 8)

#define SCSI_IOFMT_ARGS(io) io->instance_index, SCSI_ITT_SIZE(io->ocs), io->init_task_tag, SCSI_ITT_SIZE(io->ocs), io->tgt_task_tag, io->hw_tag

#define enable_tsend_auto_resp(ocs)             ((ocs->ctrlmask & OCS_CTRLMASK_XPORT_DISABLE_AUTORSP_TSEND) == 0)
#define enable_treceive_auto_resp(ocs)  ((ocs->ctrlmask & OCS_CTRLMASK_XPORT_DISABLE_AUTORSP_TRECEIVE) == 0)

#define scsi_io_printf(io, fmt, ...) ocs_log_info(io->ocs, "[%s]" SCSI_IOFMT fmt, \
        io->node->display_name, SCSI_IOFMT_ARGS(io), ##__VA_ARGS__)

#define scsi_io_trace(io, fmt, ...) \
        do { \
                if (OCS_LOG_ENABLE_SCSI_TRACE(io->ocs)) \
                        scsi_io_printf(io, fmt, ##__VA_ARGS__); \
        } while (0)

#define scsi_log(ocs, fmt, ...) \
        do { \
                if (OCS_LOG_ENABLE_SCSI_TRACE(ocs)) \
                        ocs_log_info(ocs, fmt, ##__VA_ARGS__); \
        } while (0)

static int32_t ocs_target_send_bls_resp(ocs_io_t *io, ocs_scsi_io_cb_t cb, void *arg);
static int32_t ocs_scsi_abort_io_cb(struct ocs_hw_io_s *hio, ocs_remote_node_t *rnode, uint32_t len, int32_t status,
        uint32_t ext, void *arg);

static void ocs_scsi_io_free_ovfl(ocs_io_t *io);
static uint32_t ocs_scsi_count_sgls(ocs_hw_dif_info_t *hw_dif, ocs_scsi_sgl_t *sgl, uint32_t sgl_count);
static int ocs_scsi_dif_guard_is_crc(uint8_t direction, ocs_hw_dif_info_t *dif_info);
static ocs_scsi_io_status_e ocs_scsi_dif_check_unknown(ocs_io_t *io, uint32_t length, uint32_t check_length, int is_crc);
static uint32_t ocs_scsi_dif_check_guard(ocs_hw_dif_info_t *dif_info, ocs_scsi_vaddr_len_t addrlen[],
        uint32_t addrlen_count, ocs_dif_t *dif, int is_crc);
static uint32_t ocs_scsi_dif_check_app_tag(ocs_t *ocs, ocs_hw_dif_info_t *dif_info, uint16_t exp_app_tag, ocs_dif_t *dif);
static uint32_t ocs_scsi_dif_check_ref_tag(ocs_t *ocs, ocs_hw_dif_info_t *dif_info, uint32_t exp_ref_tag, ocs_dif_t *dif);
static int32_t ocs_scsi_convert_dif_info(ocs_t *ocs, ocs_scsi_dif_info_t *scsi_dif_info,
        ocs_hw_dif_info_t *hw_dif_info);
static int32_t ocs_scsi_io_dispatch_hw_io(ocs_io_t *io, ocs_hw_io_t *hio);
static int32_t ocs_scsi_io_dispatch_no_hw_io(ocs_io_t *io);
static void _ocs_scsi_io_free(void *arg);

/**
 * @ingroup scsi_api_base
 * @brief Returns a big-endian 32-bit value given a pointer.
 *
 * @param p Pointer to the 32-bit big-endian location.
 *
 * @return Returns the byte-swapped 32-bit value.
 */

static inline uint32_t
ocs_fc_getbe32(void *p)
{
        return ocs_be32toh(*((uint32_t*)p));
}

/**
 * @ingroup scsi_api_base
 * @brief Enable IO allocation.
 *
 * @par Description
 * The SCSI and Transport IO allocation functions are enabled. If the allocation functions
 * are not enabled, then calls to ocs_scsi_io_alloc() (and ocs_els_io_alloc() for FC) will
 * fail.
 *
 * @param node Pointer to node object.
 *
 * @return None.
 */
void
ocs_scsi_io_alloc_enable(ocs_node_t *node)
{
        ocs_assert(node != NULL);
        ocs_lock(&node->active_ios_lock);
                node->io_alloc_enabled = TRUE;
        ocs_unlock(&node->active_ios_lock);
}

/**
 * @ingroup scsi_api_base
 * @brief Disable IO allocation
 *
 * @par Description
 * The SCSI and Transport IO allocation functions are disabled. If the allocation functions
 * are not enabled, then calls to ocs_scsi_io_alloc() (and ocs_els_io_alloc() for FC) will
 * fail.
 *
 * @param node Pointer to node object
 *
 * @return None.
 */
void
ocs_scsi_io_alloc_disable(ocs_node_t *node)
{
        ocs_assert(node != NULL);
        ocs_lock(&node->active_ios_lock);
                node->io_alloc_enabled = FALSE;
        ocs_unlock(&node->active_ios_lock);
}

/**
 * @ingroup scsi_api_base
 * @brief Allocate a SCSI IO context.
 *
 * @par Description
 * A SCSI IO context is allocated and associated with a @c node. This function
 * is called by an initiator-client when issuing SCSI commands to remote
 * target devices. On completion, ocs_scsi_io_free() is called.
 * @n @n
 * The returned ocs_io_t structure has an element of type ocs_scsi_ini_io_t named
 * "ini_io" that is declared and used by an initiator-client for private information.
 *
 * @param node Pointer to the associated node structure.
 * @param role Role for IO (originator/responder).
 *
 * @return Returns the pointer to the IO context, or NULL.
 *
 */

ocs_io_t *
ocs_scsi_io_alloc(ocs_node_t *node, ocs_scsi_io_role_e role)
{
        ocs_t *ocs;
        ocs_xport_t *xport;
        ocs_io_t *io;

        ocs_assert(node, NULL);
        ocs_assert(node->ocs, NULL);

        ocs = node->ocs;
        ocs_assert(ocs->xport, NULL);
        xport = ocs->xport;

        ocs_lock(&node->active_ios_lock);

                if (!node->io_alloc_enabled) {
                        ocs_unlock(&node->active_ios_lock);
                        return NULL;
                }

                io = ocs_io_alloc(ocs);
                if (io == NULL) {
                        ocs_atomic_add_return(&xport->io_alloc_failed_count, 1);
                        ocs_unlock(&node->active_ios_lock);
                        return NULL;
                }

                /* initialize refcount */
                ocs_ref_init(&io->ref, _ocs_scsi_io_free, io);

                if (io->hio != NULL) {
                        ocs_log_err(node->ocs, "assertion failed: io->hio is not NULL\n");
                        ocs_io_free(ocs, io);
                        ocs_unlock(&node->active_ios_lock);
                        return NULL;
                }

                /* set generic fields */
                io->ocs = ocs;
                io->node = node;

                /* set type and name */
                io->io_type = OCS_IO_TYPE_IO;
                io->display_name = "scsi_io";

                switch (role) {
                case OCS_SCSI_IO_ROLE_ORIGINATOR:
                        io->cmd_ini = TRUE;
                        io->cmd_tgt = FALSE;
                        break;
                case OCS_SCSI_IO_ROLE_RESPONDER:
                        io->cmd_ini = FALSE;
                        io->cmd_tgt = TRUE;
                        break;
                }

                /* Add to node's active_ios list */
                ocs_list_add_tail(&node->active_ios, io);

        ocs_unlock(&node->active_ios_lock);

        return io;
}

/**
 * @ingroup scsi_api_base
 * @brief Free a SCSI IO context (internal).
 *
 * @par Description
 * The IO context previously allocated using ocs_scsi_io_alloc()
 * is freed. This is called from within the transport layer,
 * when the reference count goes to zero.
 *
 * @param arg Pointer to the IO context.
 *
 * @return None.
 */
static void
_ocs_scsi_io_free(void *arg)
{
        ocs_io_t *io = (ocs_io_t *)arg;
        ocs_t *ocs = io->ocs;
        ocs_node_t *node = io->node;
        int send_empty_event;

        ocs_assert(io != NULL);

        scsi_io_trace(io, "freeing io 0x%p %s\n", io, io->display_name);

        ocs_assert(ocs_io_busy(io));

        ocs_lock(&node->active_ios_lock);
                ocs_list_remove(&node->active_ios, io);
                send_empty_event = (!node->io_alloc_enabled) && ocs_list_empty(&node->active_ios);
        ocs_unlock(&node->active_ios_lock);

        if (send_empty_event) {
                ocs_node_post_event(node, OCS_EVT_NODE_ACTIVE_IO_LIST_EMPTY, NULL);
        }

        io->node = NULL;
        ocs_io_free(ocs, io);

}

/**
 * @ingroup scsi_api_base
 * @brief Free a SCSI IO context.
 *
 * @par Description
 * The IO context previously allocated using ocs_scsi_io_alloc() is freed.
 *
 * @param io Pointer to the IO context.
 *
 * @return None.
 */
void
ocs_scsi_io_free(ocs_io_t *io)
{
        scsi_io_trace(io, "freeing io 0x%p %s\n", io, io->display_name);
        ocs_assert(ocs_ref_read_count(&io->ref) > 0);
        ocs_ref_put(&io->ref); /* ocs_ref_get(): ocs_scsi_io_alloc() */
}

static int32_t
ocs_scsi_send_io(ocs_hw_io_type_e type, ocs_node_t *node, ocs_io_t *io, uint64_t lun,
        ocs_scsi_tmf_cmd_e tmf, uint8_t *cdb, uint32_t cdb_len,
        ocs_scsi_dif_info_t *dif_info,
        ocs_scsi_sgl_t *sgl, uint32_t sgl_count, uint32_t wire_len, uint32_t first_burst,
        ocs_scsi_rsp_io_cb_t cb, void *arg, uint32_t flags);

/**
 * @brief Target response completion callback.
 *
 * @par Description
 * Function is called upon the completion of a target IO request.
 *
 * @param hio Pointer to the HW IO structure.
 * @param rnode Remote node associated with the IO that is completing.
 * @param length Length of the response payload.
 * @param status Completion status.
 * @param ext_status Extended completion status.
 * @param app Application-specific data (generally a pointer to the IO context).
 *
 * @return None.
 */

static void
ocs_target_io_cb(ocs_hw_io_t *hio, ocs_remote_node_t *rnode, uint32_t length,
        int32_t status, uint32_t ext_status, void *app)
{
        ocs_io_t *io = app;
        ocs_t *ocs;
        ocs_scsi_io_status_e scsi_status = OCS_SCSI_STATUS_GOOD;
        uint16_t additional_length;
        uint8_t edir;
        uint8_t tdpv;
        ocs_hw_dif_info_t *dif_info = &io->hw_dif;
        int is_crc;

        ocs_assert(io);

        scsi_io_trace(io, "status x%x ext_status x%x\n", status, ext_status);

        ocs = io->ocs;
        ocs_assert(ocs);

        ocs_scsi_io_free_ovfl(io);

        io->transferred += length;

        /* Call target server completion */
        if (io->scsi_tgt_cb) {
                ocs_scsi_io_cb_t cb = io->scsi_tgt_cb;
                uint32_t flags = 0;

                /* Clear the callback before invoking the callback */
                io->scsi_tgt_cb = NULL;

                /* if status was good, and auto-good-response was set, then callback
                 * target-server with IO_CMPL_RSP_SENT, otherwise send IO_CMPL
                 */
                if ((status == 0) && (io->auto_resp))
                        flags |= OCS_SCSI_IO_CMPL_RSP_SENT;
                else
                        flags |= OCS_SCSI_IO_CMPL;

                switch (status) {
                case SLI4_FC_WCQE_STATUS_SUCCESS:
                        scsi_status = OCS_SCSI_STATUS_GOOD;
                        break;
                case SLI4_FC_WCQE_STATUS_DI_ERROR:
                        if (ext_status & SLI4_FC_DI_ERROR_GE) {
                                scsi_status = OCS_SCSI_STATUS_DIF_GUARD_ERROR;
                        } else if (ext_status & SLI4_FC_DI_ERROR_AE) {
                                scsi_status = OCS_SCSI_STATUS_DIF_APP_TAG_ERROR;
                        } else if (ext_status & SLI4_FC_DI_ERROR_RE) {
                                scsi_status = OCS_SCSI_STATUS_DIF_REF_TAG_ERROR;
                        } else {
                                additional_length = ((ext_status >> 16) & 0xFFFF);

                                /* Capture the EDIR and TDPV bits as 0 or 1 for easier printing. */
                                edir = !!(ext_status & SLI4_FC_DI_ERROR_EDIR);
                                tdpv = !!(ext_status & SLI4_FC_DI_ERROR_TDPV);

                                is_crc = ocs_scsi_dif_guard_is_crc(edir, dif_info);

                                if (edir == 0) {
                                        /* For reads, we have everything in memory.  Start checking from beginning. */
                                        scsi_status = ocs_scsi_dif_check_unknown(io, 0, io->wire_len, is_crc);
                                } else {
                                        /* For writes, use the additional length to determine where to look for the error.
                                         * The additional_length field is set to 0 if it is not supported.
                                         * The additional length field is valid if:
                                         *    . additional_length is not zero
                                         *    . Total Data Placed is valid
                                         *    . Error Direction is RX (1)
                                         *    . Operation is a pass thru (CRC or CKSUM on IN, and CRC or CHKSUM on OUT) (all pass-thru cases except raw)
                                         */
                                        if ((additional_length != 0) && (tdpv != 0) &&
                                            (dif_info->dif == SLI4_DIF_PASS_THROUGH) && (dif_info->dif_oper != OCS_HW_SGE_DIF_OP_IN_RAW_OUT_RAW) ) {
                                                scsi_status = ocs_scsi_dif_check_unknown(io, length, additional_length, is_crc);
                                        } else {
                                                /* If we can't do additional checking, then fall-back to guard error */
                                                scsi_status = OCS_SCSI_STATUS_DIF_GUARD_ERROR;
                                        }
                                }
                        }
                        break;
                case SLI4_FC_WCQE_STATUS_LOCAL_REJECT:
                        switch (ext_status) {
                        case SLI4_FC_LOCAL_REJECT_INVALID_RELOFFSET:
                        case SLI4_FC_LOCAL_REJECT_ABORT_REQUESTED:
                                scsi_status = OCS_SCSI_STATUS_ABORTED;
                                break;
                        case SLI4_FC_LOCAL_REJECT_INVALID_RPI:
                                scsi_status = OCS_SCSI_STATUS_NEXUS_LOST;
                                break;
                        case SLI4_FC_LOCAL_REJECT_NO_XRI:
                                scsi_status = OCS_SCSI_STATUS_NO_IO;
                                break;
                        default:
                                /* TODO: we have seen 0x0d (TX_DMA_FAILED error) */
                                scsi_status = OCS_SCSI_STATUS_ERROR;
                                break;
                        }
                        break;

                case SLI4_FC_WCQE_STATUS_WQE_TIMEOUT:
                        /* target IO timed out */
                        scsi_status = OCS_SCSI_STATUS_TIMEDOUT_AND_ABORTED;
                        break;

                case SLI4_FC_WCQE_STATUS_SHUTDOWN:
                        /* Target IO cancelled by HW */
                        scsi_status = OCS_SCSI_STATUS_SHUTDOWN;
                        break;

                default:
                        scsi_status = OCS_SCSI_STATUS_ERROR;
                        break;
                }

                cb(io, scsi_status, flags, io->scsi_tgt_cb_arg);
        }
        ocs_scsi_check_pending(ocs);
}

/**
 * @brief Determine if an IO is using CRC for DIF guard format.
 *
 * @param direction IO direction: 1 for write, 0 for read.
 * @param dif_info Pointer to HW DIF info data.
 *
 * @return Returns TRUE if using CRC, FALSE if not.
 */
static int
ocs_scsi_dif_guard_is_crc(uint8_t direction, ocs_hw_dif_info_t *dif_info)
{
        int is_crc;

        if (direction) {
                /* For writes, check if operation is "OUT_CRC" or not */
                switch(dif_info->dif_oper) {
                        case OCS_HW_SGE_DIF_OP_IN_NODIF_OUT_CRC:
                        case OCS_HW_SGE_DIF_OP_IN_CRC_OUT_CRC:
                        case OCS_HW_SGE_DIF_OP_IN_CHKSUM_OUT_CRC:
                                is_crc = TRUE;
                                break;
                        default:
                                is_crc = FALSE;
                                break;
                }
        } else {
                /* For reads, check if operation is "IN_CRC" or not */
                switch(dif_info->dif_oper) {
                        case OCS_HW_SGE_DIF_OP_IN_CRC_OUT_NODIF:
                        case OCS_HW_SGE_DIF_OP_IN_CRC_OUT_CRC:
                        case OCS_HW_SGE_DIF_OP_IN_CRC_OUT_CHKSUM:
                                is_crc = TRUE;
                                break;
                        default:
                                is_crc = FALSE;
                                break;
                }
        }

        return is_crc;
}

/**
 * @brief Check a block and DIF data, computing the appropriate SCSI status
 *
 * @par Description
 * This function is used to check blocks and DIF when given an unknown DIF
 * status using the following logic:
 *
 * Given the address of the last good block, and a length of bytes that includes
 * the block with the DIF error, find the bad block. If a block is found with an
 * app_tag or ref_tag error, then return the appropriate error. No block is expected
 * to have a block guard error since hardware "fixes" the crc. So if no block in the
 * range of blocks has an error, then it is presumed to be a BLOCK GUARD error.
 *
 * @param io Pointer to the IO object.
 * @param length Length of bytes covering the good blocks.
 * @param check_length Length of bytes that covers the bad block.
 * @param is_crc True if guard is using CRC format.
 *
 * @return Returns SCSI status.
 */

static ocs_scsi_io_status_e
ocs_scsi_dif_check_unknown(ocs_io_t *io, uint32_t length, uint32_t check_length, int is_crc)
{
        uint32_t i;
        ocs_t *ocs = io->ocs;
        ocs_hw_dif_info_t *dif_info = &io->hw_dif;
        ocs_scsi_io_status_e scsi_status = OCS_SCSI_STATUS_DIF_GUARD_ERROR;
        uint32_t blocksize;                     /* data block size */
        uint64_t first_check_block;             /* first block following total data placed */
        uint64_t last_check_block;              /* last block to check */
        uint32_t check_count;                   /* count of blocks to check */
        ocs_scsi_vaddr_len_t addrlen[4];        /* address-length pairs returned from target */
        int32_t addrlen_count;                  /* count of address-length pairs */
        ocs_dif_t *dif;                         /* pointer to DIF block returned from target */
        ocs_scsi_dif_info_t scsi_dif_info = io->scsi_dif_info;

        blocksize = ocs_hw_dif_mem_blocksize(&io->hw_dif, TRUE);
        first_check_block = length / blocksize;
        last_check_block = ((length + check_length) / blocksize);
        check_count = last_check_block - first_check_block;

        ocs_log_debug(ocs, "blocksize %d first check_block %" PRId64 " last_check_block %" PRId64 " check_count %d\n",
                blocksize, first_check_block, last_check_block, check_count);

        for (i = first_check_block; i < last_check_block; i++) {
                addrlen_count = ocs_scsi_get_block_vaddr(io, (scsi_dif_info.lba + i), addrlen, ARRAY_SIZE(addrlen), (void**) &dif);
                if (addrlen_count < 0) {
                        ocs_log_test(ocs, "ocs_scsi_get_block_vaddr() failed: %d\n", addrlen_count);
                        scsi_status = OCS_SCSI_STATUS_DIF_UNKNOWN_ERROR;
                        break;
                }

                if (! ocs_scsi_dif_check_guard(dif_info, addrlen, addrlen_count, dif, is_crc)) {
                        ocs_log_debug(ocs, "block guard check error, lba %" PRId64 "\n", scsi_dif_info.lba + i);
                        scsi_status = OCS_SCSI_STATUS_DIF_GUARD_ERROR;
                        break;
                }
                if (! ocs_scsi_dif_check_app_tag(ocs, dif_info, scsi_dif_info.app_tag, dif)) {
                        ocs_log_debug(ocs, "app tag check error, lba %" PRId64 "\n", scsi_dif_info.lba + i);
                        scsi_status = OCS_SCSI_STATUS_DIF_APP_TAG_ERROR;
                        break;
                }
                if (! ocs_scsi_dif_check_ref_tag(ocs, dif_info, (scsi_dif_info.ref_tag + i), dif)) {
                        ocs_log_debug(ocs, "ref tag check error, lba %" PRId64 "\n", scsi_dif_info.lba + i);
                        scsi_status = OCS_SCSI_STATUS_DIF_REF_TAG_ERROR;
                        break;
                }
        }
        return scsi_status;
}

/**
 * @brief Check the block guard of block data
 *
 * @par Description
 * Using the dif_info for the transfer, check the block guard value.
 *
 * @param dif_info Pointer to HW DIF info data.
 * @param addrlen Array of address length pairs.
 * @param addrlen_count Number of entries in the addrlen[] array.
 * @param dif Pointer to the DIF data block being checked.
 * @param is_crc True if guard is using CRC format.
 *
 * @return Returns TRUE if block guard check is ok.
 */
static uint32_t
ocs_scsi_dif_check_guard(ocs_hw_dif_info_t *dif_info, ocs_scsi_vaddr_len_t addrlen[], uint32_t addrlen_count,
        ocs_dif_t *dif, int is_crc)
{
        uint16_t crc = dif_info->dif_seed;
        uint32_t i;
        uint16_t checksum;

        if ((dif == NULL)  || !dif_info->check_guard) {
                return TRUE;
        }

        if (is_crc) {
                for (i = 0; i < addrlen_count; i++) {
                        crc = ocs_scsi_dif_calc_crc(addrlen[i].vaddr, addrlen[i].length, crc);
                }
                return (crc == ocs_be16toh(dif->crc));
        } else {
                checksum = ocs_scsi_dif_calc_checksum(addrlen, addrlen_count);

                return (checksum == dif->crc);
        }
}

/**
 * @brief Check the app tag of dif data
 *
 * @par Description
 * Using the dif_info for the transfer, check the app tag.
 *
 * @param ocs Pointer to the ocs structure for logging.
 * @param dif_info Pointer to HW DIF info data.
 * @param exp_app_tag The value the app tag is expected to be.
 * @param dif Pointer to the DIF data block being checked.
 *
 * @return Returns TRUE if app tag check is ok.
 */
static uint32_t
ocs_scsi_dif_check_app_tag(ocs_t *ocs, ocs_hw_dif_info_t *dif_info, uint16_t exp_app_tag, ocs_dif_t *dif)
{
        if ((dif == NULL)  || !dif_info->check_app_tag) {
                return TRUE;
        }

        ocs_log_debug(ocs, "expected app tag 0x%x,  actual 0x%x\n",
                exp_app_tag, ocs_be16toh(dif->app_tag));

        return (exp_app_tag == ocs_be16toh(dif->app_tag));
}

/**
 * @brief Check the ref tag of dif data
 *
 * @par Description
 * Using the dif_info for the transfer, check the app tag.
 *
 * @param ocs Pointer to the ocs structure for logging.
 * @param dif_info Pointer to HW DIF info data.
 * @param exp_ref_tag The value the ref tag is expected to be.
 * @param dif Pointer to the DIF data block being checked.
 *
 * @return Returns TRUE if ref tag check is ok.
 */
static uint32_t
ocs_scsi_dif_check_ref_tag(ocs_t *ocs, ocs_hw_dif_info_t *dif_info, uint32_t exp_ref_tag, ocs_dif_t *dif)
{
        if ((dif == NULL)  || !dif_info->check_ref_tag) {
                return TRUE;
        }

        if (exp_ref_tag != ocs_be32toh(dif->ref_tag)) {
                ocs_log_debug(ocs, "expected ref tag 0x%x, actual 0x%x\n",
                        exp_ref_tag, ocs_be32toh(dif->ref_tag));
                return FALSE;
        } else {
                return TRUE;
        }
}

/**
 * @brief Return count of SGE's required for request
 *
 * @par Description
 * An accurate count of SGEs is computed and returned.
 *
 * @param hw_dif Pointer to HW dif information.
 * @param sgl Pointer to SGL from back end.
 * @param sgl_count Count of SGEs in SGL.
 *
 * @return Count of SGEs.
 */
static uint32_t
ocs_scsi_count_sgls(ocs_hw_dif_info_t *hw_dif, ocs_scsi_sgl_t *sgl, uint32_t sgl_count)
{
        uint32_t count = 0;
        uint32_t i;

        /* Convert DIF Information */
        if (hw_dif->dif_oper != OCS_HW_DIF_OPER_DISABLED) {
                /* If we're not DIF separate, then emit a seed SGE */
                if (!hw_dif->dif_separate) {
                        count++;
                }

                for (i = 0; i < sgl_count; i++) {
                        /* If DIF is enabled, and DIF is separate, then append a SEED then DIF SGE */
                        if (hw_dif->dif_separate) {
                                count += 2;
                        }

                        count++;
                }
        } else {
                count = sgl_count;
        }
        return count;
}

static int32_t
ocs_scsi_build_sgls(ocs_hw_t *hw, ocs_hw_io_t *hio, ocs_hw_dif_info_t *hw_dif, ocs_scsi_sgl_t *sgl, uint32_t sgl_count, ocs_hw_io_type_e type)
{
        int32_t rc;
        uint32_t i;
        ocs_t *ocs = hw->os;
        uint32_t blocksize = 0;
        uint32_t blockcount;

        ocs_assert(hio, -1);

        /* Initialize HW SGL */
        rc = ocs_hw_io_init_sges(hw, hio, type);
        if (rc) {
                ocs_log_err(ocs, "ocs_hw_io_init_sges failed: %d\n", rc);
                return -1;
        }

        /* Convert DIF Information */
        if (hw_dif->dif_oper != OCS_HW_DIF_OPER_DISABLED) {
                /* If we're not DIF separate, then emit a seed SGE */
                if (!hw_dif->dif_separate) {
                        rc = ocs_hw_io_add_seed_sge(hw, hio, hw_dif);
                        if (rc) {
                                return rc;
                        }
                }

                /* if we are doing DIF separate, then figure out the block size so that we
                 * can update the ref tag in the DIF seed SGE.   Also verify that the
                 * the sgl lengths are all multiples of the blocksize
                 */
                if (hw_dif->dif_separate) {
                        switch(hw_dif->blk_size) {
                        case OCS_HW_DIF_BK_SIZE_512:    blocksize = 512; break;
                        case OCS_HW_DIF_BK_SIZE_1024:   blocksize = 1024; break;
                        case OCS_HW_DIF_BK_SIZE_2048:   blocksize = 2048; break;
                        case OCS_HW_DIF_BK_SIZE_4096:   blocksize = 4096; break;
                        case OCS_HW_DIF_BK_SIZE_520:    blocksize = 520; break;
                        case OCS_HW_DIF_BK_SIZE_4104:   blocksize = 4104; break;
                        default:
                                ocs_log_test(hw->os, "Invalid hw_dif blocksize %d\n", hw_dif->blk_size);
                                return -1;
                        }
                        for (i = 0; i < sgl_count; i++) {
                                if ((sgl[i].len % blocksize) != 0) {
                                        ocs_log_test(hw->os, "sgl[%d] len of %ld is not multiple of blocksize\n",
                                                     i, sgl[i].len);
                                        return -1;
                                }
                        }
                }

                for (i = 0; i < sgl_count; i++) {
                        ocs_assert(sgl[i].addr, -1);
                        ocs_assert(sgl[i].len, -1);

                        /* If DIF is enabled, and DIF is separate, then append a SEED then DIF SGE */
                        if (hw_dif->dif_separate) {
                                rc = ocs_hw_io_add_seed_sge(hw, hio, hw_dif);
                                if (rc) {
                                        return rc;
                                }
                                rc = ocs_hw_io_add_dif_sge(hw, hio, sgl[i].dif_addr);
                                if (rc) {
                                        return rc;
                                }
                                /* Update the ref_tag for the next DIF seed SGE */
                                blockcount = sgl[i].len / blocksize;
                                if (hw_dif->dif_oper == OCS_HW_DIF_OPER_INSERT) {
                                        hw_dif->ref_tag_repl += blockcount;
                                } else {
                                        hw_dif->ref_tag_cmp += blockcount;
                                }
                        }

                        /* Add data SGE */
                        rc = ocs_hw_io_add_sge(hw, hio, sgl[i].addr, sgl[i].len);
                        if (rc) {
                                ocs_log_err(ocs, "ocs_hw_io_add_sge failed: count=%d rc=%d\n",
                                                sgl_count, rc);
                                return rc;
                        }
                }
        } else {
                for (i = 0; i < sgl_count; i++) {
                        ocs_assert(sgl[i].addr, -1);
                        ocs_assert(sgl[i].len, -1);

                        /* Add data SGE */
                        rc = ocs_hw_io_add_sge(hw, hio, sgl[i].addr, sgl[i].len);
                        if (rc) {
                                ocs_log_err(ocs, "ocs_hw_io_add_sge failed: count=%d rc=%d\n",
                                                sgl_count, rc);
                                return rc;
                        }
                }
        }
        return 0;
}

/**
 * @ingroup scsi_api_base
 * @brief Convert SCSI API T10 DIF information into the FC HW format.
 *
 * @param ocs Pointer to the ocs structure for logging.
 * @param scsi_dif_info Pointer to the SCSI API T10 DIF fields.
 * @param hw_dif_info Pointer to the FC HW API T10 DIF fields.
 *
 * @return Returns 0 on success, or a negative error code value on failure.
 */

static int32_t
ocs_scsi_convert_dif_info(ocs_t *ocs, ocs_scsi_dif_info_t *scsi_dif_info, ocs_hw_dif_info_t *hw_dif_info)
{
        uint32_t dif_seed;
        ocs_memset(hw_dif_info, 0, sizeof(ocs_hw_dif_info_t));

        if (scsi_dif_info == NULL) {
                hw_dif_info->dif_oper = OCS_HW_DIF_OPER_DISABLED;
                hw_dif_info->blk_size =  OCS_HW_DIF_BK_SIZE_NA;
                return 0;
        }

        /* Convert the DIF operation */
        switch(scsi_dif_info->dif_oper) {
        case OCS_SCSI_DIF_OPER_IN_NODIF_OUT_CRC:
                hw_dif_info->dif_oper = OCS_HW_SGE_DIF_OP_IN_NODIF_OUT_CRC;
                hw_dif_info->dif = SLI4_DIF_INSERT;
                break;
        case OCS_SCSI_DIF_OPER_IN_CRC_OUT_NODIF:
                hw_dif_info->dif_oper = OCS_HW_SGE_DIF_OP_IN_CRC_OUT_NODIF;
                hw_dif_info->dif = SLI4_DIF_STRIP;
                break;
        case OCS_SCSI_DIF_OPER_IN_NODIF_OUT_CHKSUM:
                hw_dif_info->dif_oper = OCS_HW_SGE_DIF_OP_IN_NODIF_OUT_CHKSUM;
                hw_dif_info->dif = SLI4_DIF_INSERT;
                break;
        case OCS_SCSI_DIF_OPER_IN_CHKSUM_OUT_NODIF:
                hw_dif_info->dif_oper = OCS_HW_SGE_DIF_OP_IN_CHKSUM_OUT_NODIF;
                hw_dif_info->dif = SLI4_DIF_STRIP;
                break;
        case OCS_SCSI_DIF_OPER_IN_CRC_OUT_CRC:
                hw_dif_info->dif_oper = OCS_HW_SGE_DIF_OP_IN_CRC_OUT_CRC;
                hw_dif_info->dif = SLI4_DIF_PASS_THROUGH;
                break;
        case OCS_SCSI_DIF_OPER_IN_CHKSUM_OUT_CHKSUM:
                hw_dif_info->dif_oper = OCS_HW_SGE_DIF_OP_IN_CHKSUM_OUT_CHKSUM;
                hw_dif_info->dif = SLI4_DIF_PASS_THROUGH;
                break;
        case OCS_SCSI_DIF_OPER_IN_CRC_OUT_CHKSUM:
                hw_dif_info->dif_oper = OCS_HW_SGE_DIF_OP_IN_CRC_OUT_CHKSUM;
                hw_dif_info->dif = SLI4_DIF_PASS_THROUGH;
                break;
        case OCS_SCSI_DIF_OPER_IN_CHKSUM_OUT_CRC:
                hw_dif_info->dif_oper = OCS_HW_SGE_DIF_OP_IN_CHKSUM_OUT_CRC;
                hw_dif_info->dif = SLI4_DIF_PASS_THROUGH;
                break;
        case OCS_SCSI_DIF_OPER_IN_RAW_OUT_RAW:
                hw_dif_info->dif_oper = OCS_HW_SGE_DIF_OP_IN_RAW_OUT_RAW;
                hw_dif_info->dif = SLI4_DIF_PASS_THROUGH;
                break;
        default:
                ocs_log_test(ocs, "unhandled SCSI DIF operation %d\n",
                             scsi_dif_info->dif_oper);
                return -1;
        }

        switch(scsi_dif_info->blk_size) {
        case OCS_SCSI_DIF_BK_SIZE_512:
                hw_dif_info->blk_size = OCS_HW_DIF_BK_SIZE_512;
                break;
        case OCS_SCSI_DIF_BK_SIZE_1024:
                hw_dif_info->blk_size = OCS_HW_DIF_BK_SIZE_1024;
                break;
        case OCS_SCSI_DIF_BK_SIZE_2048:
                hw_dif_info->blk_size = OCS_HW_DIF_BK_SIZE_2048;
                break;
        case OCS_SCSI_DIF_BK_SIZE_4096:
                hw_dif_info->blk_size = OCS_HW_DIF_BK_SIZE_4096;
                break;
        case OCS_SCSI_DIF_BK_SIZE_520:
                hw_dif_info->blk_size = OCS_HW_DIF_BK_SIZE_520;
                break;
        case OCS_SCSI_DIF_BK_SIZE_4104:
                hw_dif_info->blk_size = OCS_HW_DIF_BK_SIZE_4104;
                break;
        default:
                ocs_log_test(ocs, "unhandled SCSI DIF block size %d\n",
                             scsi_dif_info->blk_size);
                return -1;
        }

        /* If the operation is an INSERT the tags provided are the ones that should be
         * inserted, otherwise they're the ones to be checked against. */
        if (hw_dif_info->dif == SLI4_DIF_INSERT ) {
                hw_dif_info->ref_tag_repl = scsi_dif_info->ref_tag;
                hw_dif_info->app_tag_repl = scsi_dif_info->app_tag;
        } else {
                hw_dif_info->ref_tag_cmp = scsi_dif_info->ref_tag;
                hw_dif_info->app_tag_cmp = scsi_dif_info->app_tag;
        }

        hw_dif_info->check_ref_tag = scsi_dif_info->check_ref_tag;
        hw_dif_info->check_app_tag = scsi_dif_info->check_app_tag;
        hw_dif_info->check_guard = scsi_dif_info->check_guard;
        hw_dif_info->auto_incr_ref_tag = 1;
        hw_dif_info->dif_separate = scsi_dif_info->dif_separate;
        hw_dif_info->disable_app_ffff = scsi_dif_info->disable_app_ffff;
        hw_dif_info->disable_app_ref_ffff = scsi_dif_info->disable_app_ref_ffff;

        ocs_hw_get(&ocs->hw, OCS_HW_DIF_SEED, &dif_seed);
        hw_dif_info->dif_seed = dif_seed;

        return 0;
}

/**
 * @ingroup scsi_api_base
 * @brief This function logs the SGLs for an IO.
 *
 * @param io Pointer to the IO context.
 */
static void ocs_log_sgl(ocs_io_t *io)
{
        ocs_hw_io_t *hio = io->hio;
        sli4_sge_t *data = NULL;
        uint32_t *dword = NULL;
        uint32_t i;
        uint32_t n_sge;

        scsi_io_trace(io, "def_sgl at 0x%x 0x%08x\n",
                      ocs_addr32_hi(hio->def_sgl.phys),
                      ocs_addr32_lo(hio->def_sgl.phys));
        n_sge = (hio->sgl == &hio->def_sgl ? hio->n_sge : hio->def_sgl_count);
        for (i = 0, data = hio->def_sgl.virt; i < n_sge; i++, data++) {
                dword = (uint32_t*)data;

                scsi_io_trace(io, "SGL %2d 0x%08x 0x%08x 0x%08x 0x%08x\n",
                         i, dword[0], dword[1], dword[2], dword[3]);

                if (dword[2] & (1U << 31)) {
                        break;
                }
        }

        if (hio->ovfl_sgl != NULL &&
                hio->sgl == hio->ovfl_sgl) {
                scsi_io_trace(io, "Overflow at 0x%x 0x%08x\n",
                              ocs_addr32_hi(hio->ovfl_sgl->phys),
                              ocs_addr32_lo(hio->ovfl_sgl->phys));
                for (i = 0, data = hio->ovfl_sgl->virt; i < hio->n_sge; i++, data++) {
                        dword = (uint32_t*)data;

                        scsi_io_trace(io, "SGL %2d 0x%08x 0x%08x 0x%08x 0x%08x\n",
                                 i, dword[0], dword[1], dword[2], dword[3]);
                        if (dword[2] & (1U << 31)) {
                                break;
                        }
                }
        }

}

/**
 * @brief Check pending error asynchronous callback function.
 *
 * @par Description
 * Invoke the HW callback function for a given IO. This function is called
 * from the NOP mailbox completion context.
 *
 * @param hw Pointer to HW object.
 * @param status Completion status.
 * @param mqe Mailbox completion queue entry.
 * @param arg General purpose argument.
 *
 * @return Returns 0.
 */
static int32_t
ocs_scsi_check_pending_async_cb(ocs_hw_t *hw, int32_t status, uint8_t *mqe, void *arg)
{
        ocs_io_t *io = arg;

        if (io != NULL) {
                if (io->hw_cb != NULL) {
                        ocs_hw_done_t cb = io->hw_cb;

                        io->hw_cb = NULL;
                        cb(io->hio, NULL, 0, SLI4_FC_WCQE_STATUS_DISPATCH_ERROR, 0, io);
                }
        }
        return 0;
}

/**
 * @brief Check for pending IOs to dispatch.
 *
 * @par Description
 * If there are IOs on the pending list, and a HW IO is available, then
 * dispatch the IOs.
 *
 * @param ocs Pointer to the OCS structure.
 *
 * @return None.
 */

void
ocs_scsi_check_pending(ocs_t *ocs)
{
        ocs_xport_t *xport = ocs->xport;
        ocs_io_t *io;
        ocs_hw_io_t *hio;
        int32_t status;
        int count = 0;
        int dispatch;

        /* Guard against recursion */
        if (ocs_atomic_add_return(&xport->io_pending_recursing, 1)) {
                /* This function is already running.  Decrement and return. */
                ocs_atomic_sub_return(&xport->io_pending_recursing, 1);
                return;
        }

        do {
                ocs_lock(&xport->io_pending_lock);
                        status = 0;
                        hio = NULL;
                        io = ocs_list_remove_head(&xport->io_pending_list);
                        if (io != NULL) {
                                if (io->io_type == OCS_IO_TYPE_ABORT) {
                                        hio = NULL;
                                } else {
                                        hio = ocs_hw_io_alloc(&ocs->hw);
                                        if (hio == NULL) {
                                                /*
                                                 * No HW IO available.
                                                 * Put IO back on the front of pending list
                                                 */
                                                ocs_list_add_head(&xport->io_pending_list, io);
                                                io = NULL;
                                        } else {
                                                hio->eq = io->hw_priv;
                                        }
                                }
                        }
                /* Must drop the lock before dispatching the IO */
                ocs_unlock(&xport->io_pending_lock);

                if (io != NULL) {
                        count++;

                        /*
                         * We pulled an IO off the pending list,
                         * and either got an HW IO or don't need one
                         */
                        ocs_atomic_sub_return(&xport->io_pending_count, 1);
                        if (hio == NULL) {
                                status = ocs_scsi_io_dispatch_no_hw_io(io);
                        } else {
                                status = ocs_scsi_io_dispatch_hw_io(io, hio);
                        }
                        if (status) {
                                /*
                                 * Invoke the HW callback, but do so in the separate execution context,
                                 * provided by the NOP mailbox completion processing context by using
                                 * ocs_hw_async_call()
                                 */
                                if (ocs_hw_async_call(&ocs->hw, ocs_scsi_check_pending_async_cb, io)) {
                                        ocs_log_test(ocs, "call to ocs_hw_async_call() failed\n");
                                }
                        }
                }
        } while (io != NULL);

        /*
         * If nothing was removed from the list,
         * we might be in a case where we need to abort an
         * active IO and the abort is on the pending list.
         * Look for an abort we can dispatch.
         */
        if (count == 0 ) {
                dispatch = 0;

                ocs_lock(&xport->io_pending_lock);
                        ocs_list_foreach(&xport->io_pending_list, io) {
                                if (io->io_type == OCS_IO_TYPE_ABORT) {
                                        if (io->io_to_abort->hio != NULL) {
                                                /* This IO has a HW IO, so it is active.  Dispatch the abort. */
                                                dispatch = 1;
                                        } else {
                                                /* Leave this abort on the pending list and keep looking */
                                                dispatch = 0;
                                        }
                                }
                                if (dispatch) {
                                        ocs_list_remove(&xport->io_pending_list, io);
                                        ocs_atomic_sub_return(&xport->io_pending_count, 1);
                                        break;
                                }
                        }
                ocs_unlock(&xport->io_pending_lock);

                if (dispatch) {
                        status = ocs_scsi_io_dispatch_no_hw_io(io);
                        if (status) {
                                if (ocs_hw_async_call(&ocs->hw, ocs_scsi_check_pending_async_cb, io)) {
                                        ocs_log_test(ocs, "call to ocs_hw_async_call() failed\n");
                                }
                        }
                }
        }

        ocs_atomic_sub_return(&xport->io_pending_recursing, 1);
        return;
}

/**
 * @brief Attempt to dispatch a non-abort IO
 *
 * @par Description
 * An IO is dispatched:
 * - if the pending list is not empty, add IO to pending list
 *   and call a function to process the pending list.
 * - if pending list is empty, try to allocate a HW IO. If none
 *   is available, place this IO at the tail of the pending IO
 *   list.
 * - if HW IO is available, attach this IO to the HW IO and
 *   submit it.
 *
 * @param io Pointer to IO structure.
 * @param cb Callback function.
 *
 * @return Returns 0 on success, a negative error code value on failure.
 */

int32_t
ocs_scsi_io_dispatch(ocs_io_t *io, void *cb)
{
        ocs_hw_io_t *hio;
        ocs_t *ocs = io->ocs;
        ocs_xport_t *xport = ocs->xport;

        ocs_assert(io->cmd_tgt || io->cmd_ini, -1);
        ocs_assert((io->io_type != OCS_IO_TYPE_ABORT), -1);
        io->hw_cb = cb;

        /*
         * if this IO already has a HW IO, then this is either not the first phase of
         * the IO. Send it to the HW.
         */
        if (io->hio != NULL) {
                return ocs_scsi_io_dispatch_hw_io(io, io->hio);
        }

        /*
         * We don't already have a HW IO associated with the IO. First check
         * the pending list. If not empty, add IO to the tail and process the
         * pending list.
         */
        ocs_lock(&xport->io_pending_lock);
                if (!ocs_list_empty(&xport->io_pending_list)) {
                        /*
                         * If this is a low latency request, the put at the front of the IO pending
                         * queue, otherwise put it at the end of the queue.
                         */
                        if (io->low_latency) {
                                ocs_list_add_head(&xport->io_pending_list, io);
                        } else {
                                ocs_list_add_tail(&xport->io_pending_list, io);
                        }
                        ocs_unlock(&xport->io_pending_lock);
                        ocs_atomic_add_return(&xport->io_pending_count, 1);
                        ocs_atomic_add_return(&xport->io_total_pending, 1);

                        /* process pending list */
                        ocs_scsi_check_pending(ocs);
                        return 0;
                }
        ocs_unlock(&xport->io_pending_lock);

        /*
         * We don't have a HW IO associated with the IO and there's nothing
         * on the pending list. Attempt to allocate a HW IO and dispatch it.
         */
        hio = ocs_hw_io_alloc(&io->ocs->hw);
        if (hio == NULL) {
                /* Couldn't get a HW IO. Save this IO on the pending list */
                ocs_lock(&xport->io_pending_lock);
                        ocs_list_add_tail(&xport->io_pending_list, io);
                ocs_unlock(&xport->io_pending_lock);

                ocs_atomic_add_return(&xport->io_total_pending, 1);
                ocs_atomic_add_return(&xport->io_pending_count, 1);
                return 0;
        }

        /* We successfully allocated a HW IO; dispatch to HW */
        return ocs_scsi_io_dispatch_hw_io(io, hio);
}

/**
 * @brief Attempt to dispatch an Abort IO.
 *
 * @par Description
 * An Abort IO is dispatched:
 * - if the pending list is not empty, add IO to pending list
 *   and call a function to process the pending list.
 * - if pending list is empty, send abort to the HW.
 *
 * @param io Pointer to IO structure.
 * @param cb Callback function.
 *
 * @return Returns 0 on success, a negative error code value on failure.
 */

int32_t
ocs_scsi_io_dispatch_abort(ocs_io_t *io, void *cb)
{
        ocs_t *ocs = io->ocs;
        ocs_xport_t *xport = ocs->xport;

        ocs_assert((io->io_type == OCS_IO_TYPE_ABORT), -1);
        io->hw_cb = cb;

        /*
         * For aborts, we don't need a HW IO, but we still want to pass through
         * the pending list to preserve ordering. Thus, if the pending list is
         * not empty, add this abort to the pending list and process the pending list.
         */
        ocs_lock(&xport->io_pending_lock);
                if (!ocs_list_empty(&xport->io_pending_list)) {
                        ocs_list_add_tail(&xport->io_pending_list, io);
                        ocs_unlock(&xport->io_pending_lock);
                        ocs_atomic_add_return(&xport->io_pending_count, 1);
                        ocs_atomic_add_return(&xport->io_total_pending, 1);

                        /* process pending list */
                        ocs_scsi_check_pending(ocs);
                        return 0;
                }
        ocs_unlock(&xport->io_pending_lock);

        /* nothing on pending list, dispatch abort */
        return ocs_scsi_io_dispatch_no_hw_io(io);

}

/**
 * @brief Dispatch IO
 *
 * @par Description
 * An IO and its associated HW IO is dispatched to the HW.
 *
 * @param io Pointer to IO structure.
 * @param hio Pointer to HW IO structure from which IO will be
 * dispatched.
 *
 * @return Returns 0 on success, a negative error code value on failure.
 */

static int32_t
ocs_scsi_io_dispatch_hw_io(ocs_io_t *io, ocs_hw_io_t *hio)
{
        int32_t rc;
        ocs_t *ocs = io->ocs;

        /* Got a HW IO; update ini/tgt_task_tag with HW IO info and dispatch */
        io->hio = hio;
        if (io->cmd_tgt) {
                io->tgt_task_tag = hio->indicator;
        } else if (io->cmd_ini) {
                io->init_task_tag = hio->indicator;
        }
        io->hw_tag = hio->reqtag;

        hio->eq = io->hw_priv;

        /* Copy WQ steering */
        switch(io->wq_steering) {
        case OCS_SCSI_WQ_STEERING_CLASS >> OCS_SCSI_WQ_STEERING_SHIFT:
                hio->wq_steering = OCS_HW_WQ_STEERING_CLASS;
                break;
        case OCS_SCSI_WQ_STEERING_REQUEST >> OCS_SCSI_WQ_STEERING_SHIFT:
                hio->wq_steering = OCS_HW_WQ_STEERING_REQUEST;
                break;
        case OCS_SCSI_WQ_STEERING_CPU >> OCS_SCSI_WQ_STEERING_SHIFT:
                hio->wq_steering = OCS_HW_WQ_STEERING_CPU;
                break;
        }

        switch (io->io_type) {
        case OCS_IO_TYPE_IO: {
                uint32_t max_sgl;
                uint32_t total_count;
                uint32_t host_allocated;

                ocs_hw_get(&ocs->hw, OCS_HW_N_SGL, &max_sgl);
                ocs_hw_get(&ocs->hw, OCS_HW_SGL_CHAINING_HOST_ALLOCATED, &host_allocated);

                /*
                 * If the requested SGL is larger than the default size, then we can allocate
                 * an overflow SGL.
                 */
                total_count = ocs_scsi_count_sgls(&io->hw_dif, io->sgl, io->sgl_count);

                /*
                 * Lancer requires us to allocate the chained memory area, but
                 * Skyhawk must use the SGL list associated with another XRI.
                 */
                if (host_allocated && total_count > max_sgl) {
                        /* Compute count needed, the number extra plus 1 for the link sge */
                        uint32_t count = total_count - max_sgl + 1;
                        rc = ocs_dma_alloc(ocs, &io->ovfl_sgl, count*sizeof(sli4_sge_t), 64);
                        if (rc) {
                                ocs_log_err(ocs, "ocs_dma_alloc overflow sgl failed\n");
                                break;
                        }
                        rc = ocs_hw_io_register_sgl(&ocs->hw, io->hio, &io->ovfl_sgl, count);
                        if (rc) {
                                ocs_scsi_io_free_ovfl(io);
                                ocs_log_err(ocs, "ocs_hw_io_register_sgl() failed\n");
                                break;
                        }
                        /* EVT: update chained_io_count */
                        io->node->chained_io_count++;
                }

                rc = ocs_scsi_build_sgls(&ocs->hw, io->hio, &io->hw_dif, io->sgl, io->sgl_count, io->hio_type);
                if (rc) {
                        ocs_scsi_io_free_ovfl(io);
                        break;
                }

                if (OCS_LOG_ENABLE_SCSI_TRACE(ocs)) {
                        ocs_log_sgl(io);
                }

                if (io->app_id) {
                        io->iparam.fcp_tgt.app_id = io->app_id;
                }

                rc = ocs_hw_io_send(&io->ocs->hw, io->hio_type, io->hio, io->wire_len, &io->iparam, &io->node->rnode,
                        io->hw_cb, io);
                break;
        }
        case OCS_IO_TYPE_ELS:
        case OCS_IO_TYPE_CT: {
                rc = ocs_hw_srrs_send(&ocs->hw, io->hio_type, io->hio,
                        &io->els_req, io->wire_len,
                        &io->els_rsp, &io->node->rnode, &io->iparam,
                        io->hw_cb, io);
                break;
        }
        case OCS_IO_TYPE_CT_RESP: {
                rc = ocs_hw_srrs_send(&ocs->hw, io->hio_type, io->hio,
                        &io->els_rsp, io->wire_len,
                        NULL, &io->node->rnode, &io->iparam,
                        io->hw_cb, io);
                break;
        }
        case OCS_IO_TYPE_BLS_RESP: {
                /* no need to update tgt_task_tag for BLS response since the RX_ID
                 * will be specified by the payload, not the XRI */
                rc = ocs_hw_srrs_send(&ocs->hw, io->hio_type, io->hio,
                        NULL, 0, NULL, &io->node->rnode, &io->iparam, io->hw_cb, io);
                break;
        }
        default:
                scsi_io_printf(io, "Unknown IO type=%d\n", io->io_type);
                rc = -1;
                break;
        }
        return rc;
}

/**
 * @brief Dispatch IO
 *
 * @par Description
 * An IO that does require a HW IO is dispatched to the HW.
 *
 * @param io Pointer to IO structure.
 *
 * @return Returns 0 on success, or a negative error code value on failure.
 */

static int32_t
ocs_scsi_io_dispatch_no_hw_io(ocs_io_t *io)
{
        int32_t rc;

        switch (io->io_type) {
        case OCS_IO_TYPE_ABORT: {
                ocs_hw_io_t *hio_to_abort = NULL;
                ocs_assert(io->io_to_abort, -1);
                hio_to_abort = io->io_to_abort->hio;

                if (hio_to_abort == NULL) {
                        /*
                         * If "IO to abort" does not have an associated HW IO, immediately
                         * make callback with success. The command must have been sent to
                         * the backend, but the data phase has not yet started, so we don't
                         * have a HW IO.
                         *
                         * Note: since the backend shims should be taking a reference
                         * on io_to_abort, it should not be possible to have been completed
                         * and freed by the backend before the abort got here.
                         */
                        scsi_io_printf(io, "IO: " SCSI_IOFMT " not active\n",
                                       SCSI_IOFMT_ARGS(io->io_to_abort));
                        ((ocs_hw_done_t)io->hw_cb)(io->hio, NULL, 0, SLI4_FC_WCQE_STATUS_SUCCESS, 0, io);
                        rc = 0;
                } else {
                        /* HW IO is valid, abort it */
                        scsi_io_printf(io, "aborting " SCSI_IOFMT "\n", SCSI_IOFMT_ARGS(io->io_to_abort));
                        rc = ocs_hw_io_abort(&io->ocs->hw, hio_to_abort, io->send_abts,
                                              io->hw_cb, io);
                        if (rc) {
                                int status = SLI4_FC_WCQE_STATUS_SUCCESS;
                                if ((rc != OCS_HW_RTN_IO_NOT_ACTIVE) &&
                                    (rc != OCS_HW_RTN_IO_ABORT_IN_PROGRESS)) {
                                        status = -1;
                                        scsi_io_printf(io, "Failed to abort IO: " SCSI_IOFMT " status=%d\n",
                                                       SCSI_IOFMT_ARGS(io->io_to_abort), rc);
                                }
                                ((ocs_hw_done_t)io->hw_cb)(io->hio, NULL, 0, status, 0, io);
                                rc = 0;
                        }
                }

                break;
        }
        default:
                scsi_io_printf(io, "Unknown IO type=%d\n", io->io_type);
                rc = -1;
                break;
        }
        return rc;
}

/**
 * @ingroup scsi_api_base
 * @brief Send read/write data.
 *
 * @par Description
 * This call is made by a target-server to initiate a SCSI read or write data phase, transferring
 * data between the target to the remote initiator. The payload is specified by the
 * scatter-gather list @c sgl of length @c sgl_count. The @c wire_len argument
 * specifies the payload length (independent of the scatter-gather list cumulative length).
 * @n @n
 * The @c flags argument has one bit, OCS_SCSI_LAST_DATAPHASE, which is a hint to the base
 * driver that it may use auto SCSI response features if the hardware supports it.
 * @n @n
 * Upon completion, the callback function @b cb is called with flags indicating that the
 * IO has completed (OCS_SCSI_IO_COMPL) and another data phase or response may be sent;
 * that the IO has completed and no response needs to be sent (OCS_SCSI_IO_COMPL_NO_RSP);
 * or that the IO was aborted (OCS_SCSI_IO_ABORTED).
 *
 * @param io Pointer to the IO context.
 * @param flags Flags controlling the sending of data.
 * @param dif_info Pointer to T10 DIF fields, or NULL if no DIF.
 * @param sgl Pointer to the payload scatter-gather list.
 * @param sgl_count Count of the scatter-gather list elements.
 * @param xwire_len Length of the payload on wire, in bytes.
 * @param type HW IO type.
 * @param enable_ar Enable auto-response if true.
 * @param cb Completion callback.
 * @param arg Application-supplied callback data.
 *
 * @return Returns 0 on success, or a negative error code value on failure.
 */

static inline int32_t
ocs_scsi_xfer_data(ocs_io_t *io, uint32_t flags,
        ocs_scsi_dif_info_t *dif_info,
        ocs_scsi_sgl_t *sgl, uint32_t sgl_count, uint32_t xwire_len,
        ocs_hw_io_type_e type, int enable_ar,
        ocs_scsi_io_cb_t cb, void *arg)
{
        int32_t rc;
        ocs_t *ocs;
        uint32_t disable_ar_tgt_dif = FALSE;
        size_t residual = 0;

        if ((dif_info != NULL) && (dif_info->dif_oper == OCS_SCSI_DIF_OPER_DISABLED)) {
                dif_info = NULL;
        }

        ocs_assert(io, -1);

        if (dif_info != NULL) {
                ocs_hw_get(&io->ocs->hw, OCS_HW_DISABLE_AR_TGT_DIF, &disable_ar_tgt_dif);
                if (disable_ar_tgt_dif) {
                        enable_ar = FALSE;
                }
        }

        io->sgl_count = sgl_count;

        /* If needed, copy SGL */
        if (sgl && (sgl != io->sgl)) {
                ocs_assert(sgl_count <= io->sgl_allocated, -1);
                ocs_memcpy(io->sgl, sgl, sgl_count*sizeof(*io->sgl));
        }

        ocs = io->ocs;
        ocs_assert(ocs, -1);
        ocs_assert(io->node, -1);

        scsi_io_trace(io, "%s wire_len %d\n", (type == OCS_HW_IO_TARGET_READ) ? "send" : "recv", xwire_len);

        ocs_assert(sgl, -1);
        ocs_assert(sgl_count > 0, -1);
        ocs_assert(io->exp_xfer_len > io->transferred, -1);

        io->hio_type = type;

        io->scsi_tgt_cb = cb;
        io->scsi_tgt_cb_arg = arg;

        rc = ocs_scsi_convert_dif_info(ocs, dif_info, &io->hw_dif);
        if (rc) {
                return rc;
        }

        /* If DIF is used, then save lba for error recovery */
        if (dif_info) {
                io->scsi_dif_info = *dif_info;
        }

        io->wire_len = MIN(xwire_len, io->exp_xfer_len - io->transferred);
        residual = (xwire_len - io->wire_len);

        ocs_memset(&io->iparam, 0, sizeof(io->iparam));
        io->iparam.fcp_tgt.ox_id = io->init_task_tag;
        io->iparam.fcp_tgt.offset = io->transferred;
        io->iparam.fcp_tgt.dif_oper = io->hw_dif.dif;
        io->iparam.fcp_tgt.blk_size = io->hw_dif.blk_size;
        io->iparam.fcp_tgt.cs_ctl = io->cs_ctl;
        io->iparam.fcp_tgt.timeout = io->timeout;

        /* if this is the last data phase and there is no residual, enable
         * auto-good-response
         */
        if (enable_ar && (flags & OCS_SCSI_LAST_DATAPHASE) &&
                (residual == 0) && ((io->transferred + io->wire_len) == io->exp_xfer_len) && (!(flags & OCS_SCSI_NO_AUTO_RESPONSE))) {
                io->iparam.fcp_tgt.flags |= SLI4_IO_AUTO_GOOD_RESPONSE;
                io->auto_resp = TRUE;
        } else {
                io->auto_resp = FALSE;
        }

        /* save this transfer length */
        io->xfer_req = io->wire_len;

        /* Adjust the transferred count to account for overrun
         * when the residual is calculated in ocs_scsi_send_resp
         */
        io->transferred += residual;

        /* Adjust the SGL size if there is overrun */

        if (residual) {
                ocs_scsi_sgl_t  *sgl_ptr = &io->sgl[sgl_count-1];

                while (residual) {
                        size_t len = sgl_ptr->len;
                        if ( len > residual) {
                                sgl_ptr->len = len - residual;
                                residual = 0;
                        } else {
                                sgl_ptr->len = 0;
                                residual -= len;
                                io->sgl_count--;
                        }
                        sgl_ptr--;
                }
        }

        /* Set latency and WQ steering */
        io->low_latency = (flags & OCS_SCSI_LOW_LATENCY) != 0;
        io->wq_steering = (flags & OCS_SCSI_WQ_STEERING_MASK) >> OCS_SCSI_WQ_STEERING_SHIFT;
        io->wq_class = (flags & OCS_SCSI_WQ_CLASS_MASK) >> OCS_SCSI_WQ_CLASS_SHIFT;

        return ocs_scsi_io_dispatch(io, ocs_target_io_cb);
}

int32_t
ocs_scsi_send_rd_data(ocs_io_t *io, uint32_t flags,
        ocs_scsi_dif_info_t *dif_info,
        ocs_scsi_sgl_t *sgl, uint32_t sgl_count, uint32_t len,
        ocs_scsi_io_cb_t cb, void *arg)
{
        return ocs_scsi_xfer_data(io, flags, dif_info, sgl, sgl_count, len, OCS_HW_IO_TARGET_READ,
                                  enable_tsend_auto_resp(io->ocs), cb, arg);
}

int32_t
ocs_scsi_recv_wr_data(ocs_io_t *io, uint32_t flags,
        ocs_scsi_dif_info_t *dif_info,
        ocs_scsi_sgl_t *sgl, uint32_t sgl_count, uint32_t len,
        ocs_scsi_io_cb_t cb, void *arg)
{
        return ocs_scsi_xfer_data(io, flags, dif_info, sgl, sgl_count, len, OCS_HW_IO_TARGET_WRITE,
                                  enable_treceive_auto_resp(io->ocs), cb, arg);
}

/**
 * @ingroup scsi_api_base
 * @brief Free overflow SGL.
 *
 * @par Description
 * Free the overflow SGL if it is present.
 *
 * @param io Pointer to IO object.
 *
 * @return None.
 */
static void
ocs_scsi_io_free_ovfl(ocs_io_t *io) {
        if (io->ovfl_sgl.size) {
                ocs_dma_free(io->ocs, &io->ovfl_sgl);
        }
}

/**
 * @ingroup scsi_api_base
 * @brief Send response data.
 *
 * @par Description
 * This function is used by a target-server to send the SCSI response data to a remote
 * initiator node. The target-server populates the @c ocs_scsi_cmd_resp_t
 * argument with scsi status, status qualifier, sense data, and response data, as
 * needed.
 * @n @n
 * Upon completion, the callback function @c cb is invoked. The target-server will generally
 * clean up its IO context resources and call ocs_scsi_io_complete().
 *
 * @param io Pointer to the IO context.
 * @param flags Flags to control sending of the SCSI response.
 * @param rsp Pointer to the response data populated by the caller.
 * @param cb Completion callback.
 * @param arg Application-specified completion callback argument.

 * @return Returns 0 on success, or a negative error code value on failure.
 */
int32_t
ocs_scsi_send_resp(ocs_io_t *io, uint32_t flags, ocs_scsi_cmd_resp_t *rsp, ocs_scsi_io_cb_t cb, void *arg)
{
        ocs_t *ocs;
        int32_t residual;
        int auto_resp = TRUE;           /* Always try auto resp */
        uint8_t scsi_status = 0;
        uint16_t scsi_status_qualifier = 0;
        uint8_t *sense_data = NULL;
        uint32_t sense_data_length = 0;

        ocs_assert(io, -1);

        ocs = io->ocs;
        ocs_assert(ocs, -1);

        ocs_assert(io->node, -1);

        ocs_scsi_convert_dif_info(ocs, NULL, &io->hw_dif);

        if (rsp) {
                scsi_status = rsp->scsi_status;
                scsi_status_qualifier = rsp->scsi_status_qualifier;
                sense_data = rsp->sense_data;
                sense_data_length = rsp->sense_data_length;
                residual = rsp->residual;
        } else {
                residual = io->exp_xfer_len - io->transferred;
        }

        io->wire_len = 0;
        io->hio_type = OCS_HW_IO_TARGET_RSP;

        io->scsi_tgt_cb = cb;
        io->scsi_tgt_cb_arg = arg;

        ocs_memset(&io->iparam, 0, sizeof(io->iparam));
        io->iparam.fcp_tgt.ox_id = io->init_task_tag;
        io->iparam.fcp_tgt.offset = 0;
        io->iparam.fcp_tgt.cs_ctl = io->cs_ctl;
        io->iparam.fcp_tgt.timeout = io->timeout;

        /* Set low latency queueing request */
        io->low_latency = (flags & OCS_SCSI_LOW_LATENCY) != 0;
        io->wq_steering = (flags & OCS_SCSI_WQ_STEERING_MASK) >> OCS_SCSI_WQ_STEERING_SHIFT;
        io->wq_class = (flags & OCS_SCSI_WQ_CLASS_MASK) >> OCS_SCSI_WQ_CLASS_SHIFT;

        if ((scsi_status != 0) || residual || sense_data_length) {
                fcp_rsp_iu_t *fcprsp = io->rspbuf.virt;

                if (!fcprsp) {
                        ocs_log_err(ocs, "NULL response buffer\n");
                        return -1;
                }

                auto_resp = FALSE;

                ocs_memset(fcprsp, 0, sizeof(*fcprsp));

                io->wire_len += (sizeof(*fcprsp) - sizeof(fcprsp->data));

                fcprsp->scsi_status = scsi_status;
                *((uint16_t*)fcprsp->status_qualifier) = ocs_htobe16(scsi_status_qualifier);

                /* set residual status if necessary */
                if (residual != 0) {
                        /* FCP: if data transferred is less than the amount expected, then this is an
                         * underflow.  If data transferred would have been greater than the amount expected
                         * then this is an overflow
                         */
                        if (residual > 0) {
                                fcprsp->flags |= FCP_RESID_UNDER;
                                *((uint32_t *)fcprsp->fcp_resid) = ocs_htobe32(residual);
                        } else {
                                fcprsp->flags |= FCP_RESID_OVER;
                                *((uint32_t *)fcprsp->fcp_resid) = ocs_htobe32(-residual);
                        }
                }

                if (sense_data && sense_data_length) {
                        ocs_assert(sense_data_length <= sizeof(fcprsp->data), -1);
                        fcprsp->flags |= FCP_SNS_LEN_VALID;
                        ocs_memcpy(fcprsp->data, sense_data, sense_data_length);
                        *((uint32_t*)fcprsp->fcp_sns_len) = ocs_htobe32(sense_data_length);
                        io->wire_len += sense_data_length;
                }

                io->sgl[0].addr = io->rspbuf.phys;
                io->sgl[0].dif_addr = 0;
                io->sgl[0].len = io->wire_len;
                io->sgl_count = 1;
        }

        if (auto_resp) {
                io->iparam.fcp_tgt.flags |= SLI4_IO_AUTO_GOOD_RESPONSE;
        }

        return ocs_scsi_io_dispatch(io, ocs_target_io_cb);
}

/**
 * @ingroup scsi_api_base
 * @brief Send TMF response data.
 *
 * @par Description
 * This function is used by a target-server to send SCSI TMF response data to a remote
 * initiator node.
 * Upon completion, the callback function @c cb is invoked. The target-server will generally
 * clean up its IO context resources and call ocs_scsi_io_complete().
 *
 * @param io Pointer to the IO context.
 * @param rspcode TMF response code.
 * @param addl_rsp_info Additional TMF response information (may be NULL for zero data).
 * @param cb Completion callback.
 * @param arg Application-specified completion callback argument.
 *
 * @return Returns 0 on success, or a negative error code value on failure.
 */
int32_t
ocs_scsi_send_tmf_resp(ocs_io_t *io, ocs_scsi_tmf_resp_e rspcode, uint8_t addl_rsp_info[3],
                ocs_scsi_io_cb_t cb, void *arg)
{
        int32_t rc = -1;
        ocs_t *ocs = NULL;
        fcp_rsp_iu_t *fcprsp = NULL;
        fcp_rsp_info_t *rspinfo = NULL;
        uint8_t fcp_rspcode;

        ocs_assert(io, -1);
        ocs_assert(io->ocs, -1);
        ocs_assert(io->node, -1);

        ocs = io->ocs;

        io->wire_len = 0;
        ocs_scsi_convert_dif_info(ocs, NULL, &io->hw_dif);

        switch(rspcode) {
        case OCS_SCSI_TMF_FUNCTION_COMPLETE:
                fcp_rspcode = FCP_TMF_COMPLETE;
                break;
        case OCS_SCSI_TMF_FUNCTION_SUCCEEDED:
        case OCS_SCSI_TMF_FUNCTION_IO_NOT_FOUND:
                fcp_rspcode = FCP_TMF_SUCCEEDED;
                break;
        case OCS_SCSI_TMF_FUNCTION_REJECTED:
                fcp_rspcode = FCP_TMF_REJECTED;
                break;
        case OCS_SCSI_TMF_INCORRECT_LOGICAL_UNIT_NUMBER:
                fcp_rspcode = FCP_TMF_INCORRECT_LUN;
                break;
        case OCS_SCSI_TMF_SERVICE_DELIVERY:
                fcp_rspcode = FCP_TMF_FAILED;
                break;
        default:
                fcp_rspcode = FCP_TMF_REJECTED;
                break;
        }

        io->hio_type = OCS_HW_IO_TARGET_RSP;

        io->scsi_tgt_cb = cb;
        io->scsi_tgt_cb_arg = arg;

        if (io->tmf_cmd == OCS_SCSI_TMF_ABORT_TASK) {
                rc = ocs_target_send_bls_resp(io, cb, arg);
                return rc;
        }

        /* populate the FCP TMF response */
        fcprsp = io->rspbuf.virt;
        ocs_memset(fcprsp, 0, sizeof(*fcprsp));

        fcprsp->flags |= FCP_RSP_LEN_VALID;

        rspinfo = (fcp_rsp_info_t*) fcprsp->data;
        if (addl_rsp_info != NULL) {
                ocs_memcpy(rspinfo->addl_rsp_info, addl_rsp_info, sizeof(rspinfo->addl_rsp_info));
        }
        rspinfo->rsp_code = fcp_rspcode;

        io->wire_len = sizeof(*fcprsp) - sizeof(fcprsp->data) + sizeof(*rspinfo);

        *((uint32_t*)fcprsp->fcp_rsp_len) = ocs_htobe32(sizeof(*rspinfo));

        io->sgl[0].addr = io->rspbuf.phys;
        io->sgl[0].dif_addr = 0;
        io->sgl[0].len = io->wire_len;
        io->sgl_count = 1;

        ocs_memset(&io->iparam, 0, sizeof(io->iparam));
        io->iparam.fcp_tgt.ox_id = io->init_task_tag;
        io->iparam.fcp_tgt.offset = 0;
        io->iparam.fcp_tgt.cs_ctl = io->cs_ctl;
        io->iparam.fcp_tgt.timeout = io->timeout;

        rc = ocs_scsi_io_dispatch(io, ocs_target_io_cb);

        return rc;
}

/**
 * @brief Process target abort callback.
 *
 * @par Description
 * Accepts HW abort requests.
 *
 * @param hio HW IO context.
 * @param rnode Remote node.
 * @param length Length of response data.
 * @param status Completion status.
 * @param ext_status Extended completion status.
 * @param app Application-specified callback data.
 *
 * @return Returns 0 on success, or a negative error code value on failure.
 */

static int32_t
ocs_target_abort_cb(ocs_hw_io_t *hio, ocs_remote_node_t *rnode, uint32_t length, int32_t status, uint32_t ext_status, void *app)
{
        ocs_io_t *io = app;
        ocs_t *ocs;
        ocs_scsi_io_status_e scsi_status;

        ocs_assert(io, -1);
        ocs_assert(io->ocs, -1);

        ocs = io->ocs;

        if (io->abort_cb) {
                ocs_scsi_io_cb_t abort_cb = io->abort_cb;
                void *abort_cb_arg = io->abort_cb_arg;

                io->abort_cb = NULL;
                io->abort_cb_arg = NULL;

                switch (status) {
                case SLI4_FC_WCQE_STATUS_SUCCESS:
                        scsi_status = OCS_SCSI_STATUS_GOOD;
                        break;
                case SLI4_FC_WCQE_STATUS_LOCAL_REJECT:
                        switch (ext_status) {
                        case SLI4_FC_LOCAL_REJECT_NO_XRI:
                                scsi_status = OCS_SCSI_STATUS_NO_IO;
                                break;
                        case SLI4_FC_LOCAL_REJECT_ABORT_IN_PROGRESS:
                                scsi_status = OCS_SCSI_STATUS_ABORT_IN_PROGRESS;
                                break;
                        default:
                                /* TODO: we have seen 0x15 (abort in progress) */
                                scsi_status = OCS_SCSI_STATUS_ERROR;
                                break;
                        }
                        break;
                case SLI4_FC_WCQE_STATUS_FCP_RSP_FAILURE:
                        scsi_status = OCS_SCSI_STATUS_CHECK_RESPONSE;
                        break;
                default:
                        scsi_status = OCS_SCSI_STATUS_ERROR;
                        break;
                }
                /* invoke callback */
                abort_cb(io->io_to_abort, scsi_status, 0, abort_cb_arg);
        }

        ocs_assert(io != io->io_to_abort, -1);

        /* done with IO to abort */
        ocs_ref_put(&io->io_to_abort->ref); /* ocs_ref_get(): ocs_scsi_tgt_abort_io() */

        ocs_io_free(ocs, io);

        ocs_scsi_check_pending(ocs);
        return 0;
}

/**
 * @ingroup scsi_api_base
 * @brief Abort a target IO.
 *
 * @par Description
 * This routine is called from a SCSI target-server. It initiates an abort of a
 * previously-issued target data phase or response request.
 *
 * @param io IO context.
 * @param cb SCSI target server callback.
 * @param arg SCSI target server supplied callback argument.
 *
 * @return Returns 0 on success, or a non-zero value on failure.
 */
int32_t
ocs_scsi_tgt_abort_io(ocs_io_t *io, ocs_scsi_io_cb_t cb, void *arg)
{
        ocs_t *ocs;
        ocs_xport_t *xport;
        int32_t rc;

        ocs_io_t *abort_io = NULL;
        ocs_assert(io, -1);
        ocs_assert(io->node, -1);
        ocs_assert(io->ocs, -1);

        ocs = io->ocs;
        xport = ocs->xport;

        /* take a reference on IO being aborted */
        if ((ocs_ref_get_unless_zero(&io->ref) == 0)) {
                /* command no longer active */
                scsi_io_printf(io, "command no longer active\n");
                return -1;
        }

        /*
         * allocate a new IO to send the abort request. Use ocs_io_alloc() directly, as
         * we need an IO object that will not fail allocation due to allocations being
         * disabled (in ocs_scsi_io_alloc())
         */
        abort_io = ocs_io_alloc(ocs);
        if (abort_io == NULL) {
                ocs_atomic_add_return(&xport->io_alloc_failed_count, 1);
                ocs_ref_put(&io->ref); /* ocs_ref_get(): same function */
                return -1;
        }

        /* Save the target server callback and argument */
        ocs_assert(abort_io->hio == NULL, -1);

        /* set generic fields */
        abort_io->cmd_tgt = TRUE;
        abort_io->node = io->node;

        /* set type and abort-specific fields */
        abort_io->io_type = OCS_IO_TYPE_ABORT;
        abort_io->display_name = "tgt_abort";
        abort_io->io_to_abort = io;
        abort_io->send_abts = FALSE;
        abort_io->abort_cb = cb;
        abort_io->abort_cb_arg = arg;

        /* now dispatch IO */
        rc = ocs_scsi_io_dispatch_abort(abort_io, ocs_target_abort_cb);
        if (rc) {
                ocs_ref_put(&io->ref); /* ocs_ref_get(): same function */
        }
        return rc;
}

/**
 * @brief Process target BLS response callback.
 *
 * @par Description
 * Accepts HW abort requests.
 *
 * @param hio HW IO context.
 * @param rnode Remote node.
 * @param length Length of response data.
 * @param status Completion status.
 * @param ext_status Extended completion status.
 * @param app Application-specified callback data.
 *
 * @return Returns 0 on success, or a negative error code value on failure.
 */

static int32_t
ocs_target_bls_resp_cb(ocs_hw_io_t *hio, ocs_remote_node_t *rnode, uint32_t length, int32_t status, uint32_t ext_status, void *app)
{
        ocs_io_t *io = app;
        ocs_t *ocs;
        ocs_scsi_io_status_e bls_status;

        ocs_assert(io, -1);
        ocs_assert(io->ocs, -1);

        ocs = io->ocs;

        /* BLS isn't really a "SCSI" concept, but use SCSI status */
        if (status) {
                io_error_log(io, "s=%#x x=%#x\n", status, ext_status);
                bls_status = OCS_SCSI_STATUS_ERROR;
        } else {
                bls_status = OCS_SCSI_STATUS_GOOD;
        }

        if (io->bls_cb) {
                ocs_scsi_io_cb_t bls_cb = io->bls_cb;
                void *bls_cb_arg = io->bls_cb_arg;

                io->bls_cb = NULL;
                io->bls_cb_arg = NULL;

                /* invoke callback */
                bls_cb(io, bls_status, 0, bls_cb_arg);
        }

        ocs_scsi_check_pending(ocs);
        return 0;
}

/**
 * @brief Complete abort request.
 *
 * @par Description
 * An abort request is completed by posting a BA_ACC for the IO that requested the abort.
 *
 * @param io Pointer to the IO context.
 * @param cb Callback function to invoke upon completion.
 * @param arg Application-specified completion callback argument.
 *
 * @return Returns 0 on success, or a negative error code value on failure.
 */

static int32_t
ocs_target_send_bls_resp(ocs_io_t *io, ocs_scsi_io_cb_t cb, void *arg)
{
        int32_t rc;
        fc_ba_acc_payload_t *acc;

        ocs_assert(io, -1);

        /* fill out IO structure with everything needed to send BA_ACC */
        ocs_memset(&io->iparam, 0, sizeof(io->iparam));
        io->iparam.bls.ox_id = io->init_task_tag;
        io->iparam.bls.rx_id = io->abort_rx_id;

        acc = (void *)io->iparam.bls.payload;

        ocs_memset(io->iparam.bls.payload, 0, sizeof(io->iparam.bls.payload));
        acc->ox_id = io->iparam.bls.ox_id;
        acc->rx_id = io->iparam.bls.rx_id;
        acc->high_seq_cnt = UINT16_MAX;

        /* generic io fields have already been populated */

        /* set type and BLS-specific fields */
        io->io_type = OCS_IO_TYPE_BLS_RESP;
        io->display_name = "bls_rsp";
        io->hio_type = OCS_HW_BLS_ACC;
        io->bls_cb = cb;
        io->bls_cb_arg = arg;

        /* dispatch IO */
        rc = ocs_scsi_io_dispatch(io, ocs_target_bls_resp_cb);
        return rc;
}

/**
 * @ingroup scsi_api_base
 * @brief Notify the base driver that the IO is complete.
 *
 * @par Description
 * This function is called by a target-server to notify the base driver that an IO
 * has completed, allowing for the base driver to free resources.
 * @n
 * @n @b Note: This function is not called by initiator-clients.
 *
 * @param io Pointer to IO context.
 *
 * @return None.
 */
void
ocs_scsi_io_complete(ocs_io_t *io)
{
        ocs_assert(io);

        if (!ocs_io_busy(io)) {
                ocs_log_test(io->ocs, "Got completion for non-busy io with tag 0x%x\n", io->tag);
                return;
        }

        scsi_io_trace(io, "freeing io 0x%p %s\n", io, io->display_name);
        ocs_assert(ocs_ref_read_count(&io->ref) > 0);
        ocs_ref_put(&io->ref); /* ocs_ref_get(): ocs_scsi_io_alloc() */
}

/**
 * @brief Handle initiator IO completion.
 *
 * @par Description
 * This callback is made upon completion of an initiator operation (initiator read/write command).
 *
 * @param hio HW IO context.
 * @param rnode Remote node.
 * @param length Length of completion data.
 * @param status Completion status.
 * @param ext_status Extended completion status.
 * @param app Application-specified callback data.
 *
 * @return None.
 */

static void
ocs_initiator_io_cb(ocs_hw_io_t *hio, ocs_remote_node_t *rnode, uint32_t length,
        int32_t status, uint32_t ext_status, void *app)
{
        ocs_io_t *io = app;
        ocs_t *ocs;
        ocs_scsi_io_status_e scsi_status;

        ocs_assert(io);
        ocs_assert(io->scsi_ini_cb);

        scsi_io_trace(io, "status x%x ext_status x%x\n", status, ext_status);

        ocs = io->ocs;
        ocs_assert(ocs);

        ocs_scsi_io_free_ovfl(io);

        /* Call target server completion */
        if (io->scsi_ini_cb) {
                fcp_rsp_iu_t *fcprsp = io->rspbuf.virt;
                ocs_scsi_cmd_resp_t rsp;
                ocs_scsi_rsp_io_cb_t cb = io->scsi_ini_cb;
                uint32_t flags = 0;
                uint8_t *pd = fcprsp->data;

                /* Clear the callback before invoking the callback */
                io->scsi_ini_cb = NULL;

                ocs_memset(&rsp, 0, sizeof(rsp));

                /* Unless status is FCP_RSP_FAILURE, fcprsp is not filled in */
                switch (status) {
                case SLI4_FC_WCQE_STATUS_SUCCESS:
                        scsi_status = OCS_SCSI_STATUS_GOOD;
                        break;
                case SLI4_FC_WCQE_STATUS_FCP_RSP_FAILURE:
                        scsi_status = OCS_SCSI_STATUS_CHECK_RESPONSE;
                        rsp.scsi_status = fcprsp->scsi_status;
                        rsp.scsi_status_qualifier = ocs_be16toh(*((uint16_t*)fcprsp->status_qualifier));

                        if (fcprsp->flags & FCP_RSP_LEN_VALID) {
                                rsp.response_data = pd;
                                rsp.response_data_length = ocs_fc_getbe32(fcprsp->fcp_rsp_len);
                                pd += rsp.response_data_length;
                        }
                        if (fcprsp->flags & FCP_SNS_LEN_VALID) {
                                uint32_t sns_len = ocs_fc_getbe32(fcprsp->fcp_sns_len);
                                rsp.sense_data = pd;
                                rsp.sense_data_length = sns_len;
                                pd += sns_len;
                        }
                        /* Set residual */
                        if (fcprsp->flags & FCP_RESID_OVER) {
                                rsp.residual = -ocs_fc_getbe32(fcprsp->fcp_resid);
                                rsp.response_wire_length = length;
                        } else  if (fcprsp->flags & FCP_RESID_UNDER) {
                                rsp.residual = ocs_fc_getbe32(fcprsp->fcp_resid);
                                rsp.response_wire_length = length;
                        }

                        /*
                         * Note: The FCP_RSP_FAILURE can be returned for initiator IOs when the total data
                         * placed does not match the requested length even if the status is good. If
                         * the status is all zeroes, then we have to assume that a frame(s) were
                         * dropped and change the status to LOCAL_REJECT/OUT_OF_ORDER_DATA
                         */
                        if (length != io->wire_len) {
                                uint32_t rsp_len = ext_status;
                                uint8_t *rsp_bytes = io->rspbuf.virt;
                                uint32_t i;
                                uint8_t all_zeroes = (rsp_len > 0);
                                /* Check if the rsp is zero */
                                for (i = 0; i < rsp_len; i++) {
                                        if (rsp_bytes[i] != 0) {
                                                all_zeroes = FALSE;
                                                break;
                                        }
                                }
                                if (all_zeroes) {
                                        scsi_status = OCS_SCSI_STATUS_ERROR;
                                        ocs_log_test(io->ocs, "[%s]" SCSI_IOFMT "local reject=0x%02x\n",
                                                     io->node->display_name, SCSI_IOFMT_ARGS(io),
                                                     SLI4_FC_LOCAL_REJECT_OUT_OF_ORDER_DATA);
                                }
                        }
                        break;
                case SLI4_FC_WCQE_STATUS_LOCAL_REJECT:
                        if (ext_status == SLI4_FC_LOCAL_REJECT_SEQUENCE_TIMEOUT) {
                                scsi_status = OCS_SCSI_STATUS_COMMAND_TIMEOUT;
                        } else {
                                scsi_status = OCS_SCSI_STATUS_ERROR;
                        }
                        break;
                case SLI4_FC_WCQE_STATUS_WQE_TIMEOUT:
                        /* IO timed out */
                        scsi_status = OCS_SCSI_STATUS_TIMEDOUT_AND_ABORTED;
                        break;
                case SLI4_FC_WCQE_STATUS_DI_ERROR:
                        if (ext_status & 0x01) {
                                scsi_status = OCS_SCSI_STATUS_DIF_GUARD_ERROR;
                        } else if (ext_status & 0x02) {
                                scsi_status = OCS_SCSI_STATUS_DIF_APP_TAG_ERROR;
                        } else if (ext_status & 0x04) {
                                scsi_status = OCS_SCSI_STATUS_DIF_REF_TAG_ERROR;
                        } else {
                                scsi_status = OCS_SCSI_STATUS_DIF_UNKNOWN_ERROR;
                        }
                        break;
                default:
                        scsi_status = OCS_SCSI_STATUS_ERROR;
                        break;
                }

                cb(io, scsi_status, &rsp, flags, io->scsi_ini_cb_arg);
        }
        ocs_scsi_check_pending(ocs);
}

/**
 * @ingroup scsi_api_base
 * @brief Initiate initiator read IO.
 *
 * @par Description
 * This call is made by an initiator-client to send a SCSI read command. The payload
 * for the command is given by a scatter-gather list @c sgl for @c sgl_count
 * entries.
 * @n @n
 * Upon completion, the callback @b cb is invoked and passed request status.
 * If the command completed successfully, the callback is given SCSI response data.
 *
 * @param node Pointer to the node.
 * @param io Pointer to the IO context.
 * @param lun LUN value.
 * @param cdb Pointer to the CDB.
 * @param cdb_len Length of the CDB.
 * @param dif_info Pointer to the T10 DIF fields, or NULL if no DIF.
 * @param sgl Pointer to the scatter-gather list.
 * @param sgl_count Count of the scatter-gather list elements.
 * @param wire_len Length of the payload.
 * @param cb Completion callback.
 * @param arg Application-specified completion callback argument.
 *
 * @return Returns 0 on success, or a negative error code value on failure.
 */
int32_t
ocs_scsi_send_rd_io(ocs_node_t *node, ocs_io_t *io, uint64_t lun, void *cdb, uint32_t cdb_len,
        ocs_scsi_dif_info_t *dif_info,
        ocs_scsi_sgl_t *sgl, uint32_t sgl_count, uint32_t wire_len,
        ocs_scsi_rsp_io_cb_t cb, void *arg, uint32_t flags)
{
        int32_t rc;

        rc = ocs_scsi_send_io(OCS_HW_IO_INITIATOR_READ, node, io, lun, 0, cdb, cdb_len, dif_info, sgl, sgl_count,
                              wire_len, 0, cb, arg, flags);

        return rc;
}

/**
 * @ingroup scsi_api_base
 * @brief Initiate initiator write IO.
 *
 * @par Description
 * This call is made by an initiator-client to send a SCSI write command. The payload
 * for the command is given by a scatter-gather list @c sgl for @c sgl_count
 * entries.
 * @n @n
 * Upon completion, the callback @c cb is invoked and passed request status. If the command
 * completed successfully, the callback is given SCSI response data.
 *
 * @param node Pointer to the node.
 * @param io Pointer to IO context.
 * @param lun LUN value.
 * @param cdb Pointer to the CDB.
 * @param cdb_len Length of the CDB.
 * @param dif_info Pointer to the T10 DIF fields, or NULL if no DIF.
 * @param sgl Pointer to the scatter-gather list.
 * @param sgl_count Count of the scatter-gather list elements.
 * @param wire_len Length of the payload.
 * @param cb Completion callback.
 * @param arg Application-specified completion callback argument.
 *
 * @return Returns 0 on success, or a negative error code value on failure.
 */
int32_t ocs_scsi_send_wr_io(ocs_node_t *node, ocs_io_t *io, uint64_t lun, void *cdb, uint32_t cdb_len,
        ocs_scsi_dif_info_t *dif_info,
        ocs_scsi_sgl_t *sgl, uint32_t sgl_count, uint32_t wire_len,
        ocs_scsi_rsp_io_cb_t cb, void *arg, uint32_t flags)
{
        int32_t rc;

        rc = ocs_scsi_send_io(OCS_HW_IO_INITIATOR_WRITE, node, io, lun, 0, cdb, cdb_len, dif_info, sgl, sgl_count,
                              wire_len, 0, cb, arg, flags);

        return rc;
}

/**
 * @ingroup scsi_api_base
 * @brief Initiate initiator write IO.
 *
 * @par Description
 * This call is made by an initiator-client to send a SCSI write command. The payload
 * for the command is given by a scatter-gather list @c sgl for @c sgl_count
 * entries.
 * @n @n
 * Upon completion, the callback @c cb is invoked and passed request status. If the command
 * completed successfully, the callback is given SCSI response data.
 *
 * @param node Pointer to the node.
 * @param io Pointer to IO context.
 * @param lun LUN value.
 * @param cdb Pointer to the CDB.
 * @param cdb_len Length of the CDB.
 * @param dif_info Pointer to the T10 DIF fields, or NULL if no DIF.
 * @param sgl Pointer to the scatter-gather list.
 * @param sgl_count Count of the scatter-gather list elements.
 * @param wire_len Length of the payload.
 * @param first_burst Number of first burst bytes to send.
 * @param cb Completion callback.
 * @param arg Application-specified completion callback argument.
 *
 * @return Returns 0 on success, or a negative error code value on failure.
 */
int32_t
ocs_scsi_send_wr_io_first_burst(ocs_node_t *node, ocs_io_t *io, uint64_t lun, void *cdb, uint32_t cdb_len,
        ocs_scsi_dif_info_t *dif_info,
        ocs_scsi_sgl_t *sgl, uint32_t sgl_count, uint32_t wire_len, uint32_t first_burst,
        ocs_scsi_rsp_io_cb_t cb, void *arg, uint32_t flags)
{
        int32_t rc;

        rc = ocs_scsi_send_io(OCS_HW_IO_INITIATOR_WRITE, node, io, lun, 0, cdb, cdb_len, dif_info, sgl, sgl_count,
                              wire_len, 0, cb, arg, flags);

        return rc;
}

/**
 * @ingroup scsi_api_base
 * @brief Initiate initiator SCSI command with no data.
 *
 * @par Description
 * This call is made by an initiator-client to send a SCSI command with no data.
 * @n @n
 * Upon completion, the callback @c cb is invoked and passed request status. If the command
 * completed successfully, the callback is given SCSI response data.
 *
 * @param node Pointer to the node.
 * @param io Pointer to the IO context.
 * @param lun LUN value.
 * @param cdb Pointer to the CDB.
 * @param cdb_len Length of the CDB.
 * @param cb Completion callback.
 * @param arg Application-specified completion callback argument.
 *
 * @return Returns 0 on success, or a negative error code value on failure.
 */
int32_t ocs_scsi_send_nodata_io(ocs_node_t *node, ocs_io_t *io, uint64_t lun, void *cdb, uint32_t cdb_len,
        ocs_scsi_rsp_io_cb_t cb, void *arg, uint32_t flags)
{
        int32_t rc;

        rc = ocs_scsi_send_io(OCS_HW_IO_INITIATOR_NODATA, node, io, lun, 0, cdb, cdb_len, NULL, NULL, 0, 0, 0, cb, arg, flags);

        return rc;
}
/**
 * @ingroup scsi_api_base
 * @brief Initiate initiator task management operation.
 *
 * @par Description
 * This command is used to send a SCSI task management function command. If the command
 * requires it (QUERY_TASK_SET for example), a payload may be associated with the command.
 * If no payload is required, then @c sgl_count may be zero and @c sgl is ignored.
 * @n @n
 * Upon completion @c cb is invoked with status and SCSI response data.
 *
 * @param node Pointer to the node.
 * @param io Pointer to the IO context.
 * @param io_to_abort Pointer to the IO context to abort in the
 * case of OCS_SCSI_TMF_ABORT_TASK. Note: this can point to the
 * same the same ocs_io_t as @c io, provided that @c io does not
 * have any outstanding work requests.
 * @param lun LUN value.
 * @param tmf Task management command.
 * @param sgl Pointer to the scatter-gather list.
 * @param sgl_count Count of the scatter-gather list elements.
 * @param len Length of the payload.
 * @param cb Completion callback.
 * @param arg Application-specified completion callback argument.
 *
 * @return Returns 0 on success, or a negative error code value on failure.
 */
int32_t
ocs_scsi_send_tmf(ocs_node_t *node, ocs_io_t *io, ocs_io_t *io_to_abort, uint64_t lun, ocs_scsi_tmf_cmd_e tmf,
        ocs_scsi_sgl_t *sgl, uint32_t sgl_count, uint32_t len, ocs_scsi_rsp_io_cb_t cb, void *arg)
{
        int32_t rc;
        ocs_assert(io, -1);

        if (tmf == OCS_SCSI_TMF_ABORT_TASK) {
                ocs_assert(io_to_abort, -1);

                /* take a reference on IO being aborted */
                if ((ocs_ref_get_unless_zero(&io_to_abort->ref) == 0)) {
                        /* command no longer active */
                        scsi_io_printf(io, "command no longer active\n");
                        return -1;
                }
                /* generic io fields have already been populated */

                /* abort-specific fields */
                io->io_type = OCS_IO_TYPE_ABORT;
                io->display_name = "abort_task";
                io->io_to_abort = io_to_abort;
                io->send_abts = TRUE;
                io->scsi_ini_cb = cb;
                io->scsi_ini_cb_arg = arg;

                /* now dispatch IO */
                rc = ocs_scsi_io_dispatch_abort(io, ocs_scsi_abort_io_cb);
                if (rc) {
                        scsi_io_printf(io, "Failed to dispatch abort\n");
                        ocs_ref_put(&io->ref); /* ocs_ref_get(): same function */
                }
        } else {
                io->display_name = "tmf";
                rc = ocs_scsi_send_io(OCS_HW_IO_INITIATOR_READ, node, io, lun, tmf, NULL, 0, NULL,
                                      sgl, sgl_count, len, 0, cb, arg, 0);
        }

        return rc;
}

/**
 * @ingroup scsi_api_base
 * @brief Send an FCP IO.
 *
 * @par Description
 * An FCP read/write IO command, with optional task management flags, is sent to @c node.
 *
 * @param type HW IO type to send.
 * @param node Pointer to the node destination of the IO.
 * @param io Pointer to the IO context.
 * @param lun LUN value.
 * @param tmf Task management command.
 * @param cdb Pointer to the SCSI CDB.
 * @param cdb_len Length of the CDB, in bytes.
 * @param dif_info Pointer to the T10 DIF fields, or NULL if no DIF.
 * @param sgl Pointer to the scatter-gather list.
 * @param sgl_count Number of SGL entries in SGL.
 * @param wire_len Payload length, in bytes, of data on wire.
 * @param first_burst Number of first burst bytes to send.
 * @param cb Completion callback.
 * @param arg Application-specified completion callback argument.
 *
 * @return Returns 0 on success, or a negative error code value on failure.
 */

/* tc: could elminiate LUN, as it's part of the IO structure */

static int32_t ocs_scsi_send_io(ocs_hw_io_type_e type, ocs_node_t *node, ocs_io_t *io, uint64_t lun,
        ocs_scsi_tmf_cmd_e tmf, uint8_t *cdb, uint32_t cdb_len,
        ocs_scsi_dif_info_t *dif_info,
        ocs_scsi_sgl_t *sgl, uint32_t sgl_count, uint32_t wire_len, uint32_t first_burst,
        ocs_scsi_rsp_io_cb_t cb, void *arg, uint32_t flags)
{
        int32_t rc;
        ocs_t *ocs;
        fcp_cmnd_iu_t *cmnd;
        uint32_t cmnd_bytes = 0;
        uint32_t *fcp_dl;
        uint8_t tmf_flags = 0;

        ocs_assert(io->node, -1);
        ocs_assert(io->node == node, -1);
        ocs_assert(io, -1);
        ocs = io->ocs;
        ocs_assert(cb, -1);

        io->sgl_count = sgl_count;

        /* Copy SGL if needed */
        if (sgl != io->sgl) {
                ocs_assert(sgl_count <= io->sgl_allocated, -1);
                ocs_memcpy(io->sgl, sgl, sizeof(*io->sgl) * sgl_count);
        }

        /* save initiator and target task tags for debugging */
        io->tgt_task_tag = 0xffff;

        io->wire_len = wire_len;
        io->hio_type = type;

        if (OCS_LOG_ENABLE_SCSI_TRACE(ocs)) {
                char buf[80];
                ocs_textbuf_t txtbuf;
                uint32_t i;

                ocs_textbuf_init(ocs, &txtbuf, buf, sizeof(buf));

                ocs_textbuf_printf(&txtbuf, "cdb%d: ", cdb_len);
                for (i = 0; i < cdb_len; i ++) {
                        ocs_textbuf_printf(&txtbuf, "%02X%s", cdb[i], (i == (cdb_len-1)) ? "" : " ");
                }
                scsi_io_printf(io, "%s len %d, %s\n", (io->hio_type == OCS_HW_IO_INITIATOR_READ) ? "read" :
                        (io->hio_type == OCS_HW_IO_INITIATOR_WRITE) ? "write" : "",  io->wire_len,
                        ocs_textbuf_get_buffer(&txtbuf));
        }

        ocs_assert(io->cmdbuf.virt, -1);

        cmnd = io->cmdbuf.virt;

        ocs_assert(sizeof(*cmnd) <= io->cmdbuf.size, -1);

        ocs_memset(cmnd, 0, sizeof(*cmnd));

        /* Default FCP_CMND IU doesn't include additional CDB bytes but does include FCP_DL */
        cmnd_bytes = sizeof(fcp_cmnd_iu_t) - sizeof(cmnd->fcp_cdb_and_dl) + sizeof(uint32_t);

        fcp_dl = (uint32_t*)(&(cmnd->fcp_cdb_and_dl));

        if (cdb) {
                if (cdb_len <= 16) {
                        ocs_memcpy(cmnd->fcp_cdb, cdb, cdb_len);
                } else {
                        uint32_t addl_cdb_bytes;

                        ocs_memcpy(cmnd->fcp_cdb, cdb, 16);
                        addl_cdb_bytes = cdb_len - 16;
                        ocs_memcpy(cmnd->fcp_cdb_and_dl, &(cdb[16]), addl_cdb_bytes);
                        /* additional_fcp_cdb_length is in words, not bytes */
                        cmnd->additional_fcp_cdb_length = (addl_cdb_bytes + 3) / 4;
                        fcp_dl += cmnd->additional_fcp_cdb_length;

                        /* Round up additional CDB bytes */
                        cmnd_bytes += (addl_cdb_bytes + 3) & ~0x3;
                }
        }

        be64enc(cmnd->fcp_lun, CAM_EXTLUN_BYTE_SWIZZLE(lun));

        if (node->fcp2device) {
                if(ocs_get_crn(node, &cmnd->command_reference_number,
                                        lun)) {
                        return -1;
                }
        }
        if (flags & OCS_SCSI_CMD_HEAD_OF_QUEUE)
                cmnd->task_attribute = FCP_TASK_ATTR_HEAD_OF_QUEUE;
        else if (flags & OCS_SCSI_CMD_ORDERED)
                cmnd->task_attribute = FCP_TASK_ATTR_ORDERED;
        else if (flags & OCS_SCSI_CMD_UNTAGGED)
                cmnd->task_attribute = FCP_TASK_ATTR_UNTAGGED;
        else if (flags & OCS_SCSI_CMD_ACA)
                cmnd->task_attribute = FCP_TASK_ATTR_ACA;
        else
                cmnd->task_attribute = FCP_TASK_ATTR_SIMPLE;
        cmnd->command_priority = (flags & OCS_SCSI_PRIORITY_MASK) >>
            OCS_SCSI_PRIORITY_SHIFT;

        switch (tmf) {
        case OCS_SCSI_TMF_QUERY_TASK_SET:
                tmf_flags = FCP_QUERY_TASK_SET;
                break;
        case OCS_SCSI_TMF_ABORT_TASK_SET:
                tmf_flags = FCP_ABORT_TASK_SET;
                break;
        case OCS_SCSI_TMF_CLEAR_TASK_SET:
                tmf_flags = FCP_CLEAR_TASK_SET;
                break;
        case OCS_SCSI_TMF_QUERY_ASYNCHRONOUS_EVENT:
                tmf_flags = FCP_QUERY_ASYNCHRONOUS_EVENT;
                break;
        case OCS_SCSI_TMF_LOGICAL_UNIT_RESET:
                tmf_flags = FCP_LOGICAL_UNIT_RESET;
                break;
        case OCS_SCSI_TMF_CLEAR_ACA:
                tmf_flags = FCP_CLEAR_ACA;
                break;
        case OCS_SCSI_TMF_TARGET_RESET:
                tmf_flags = FCP_TARGET_RESET;
                break;
        default:
                tmf_flags = 0;
        }
        cmnd->task_management_flags = tmf_flags;

        *fcp_dl = ocs_htobe32(io->wire_len);

        switch (io->hio_type) {
        case OCS_HW_IO_INITIATOR_READ:
                cmnd->rddata = 1;
                break;
        case OCS_HW_IO_INITIATOR_WRITE:
                cmnd->wrdata = 1;
                break;
        case  OCS_HW_IO_INITIATOR_NODATA:
                /* sets neither */
                break;
        default:
                ocs_log_test(ocs, "bad IO type %d\n", io->hio_type);
                return -1;
        }

        rc = ocs_scsi_convert_dif_info(ocs, dif_info, &io->hw_dif);
        if (rc) {
                return rc;
        }

        io->scsi_ini_cb = cb;
        io->scsi_ini_cb_arg = arg;

        /* set command and response buffers in the iparam */
        io->iparam.fcp_ini.cmnd = &io->cmdbuf;
        io->iparam.fcp_ini.cmnd_size = cmnd_bytes;
        io->iparam.fcp_ini.rsp = &io->rspbuf;
        io->iparam.fcp_ini.flags = 0;
        io->iparam.fcp_ini.dif_oper = io->hw_dif.dif;
        io->iparam.fcp_ini.blk_size = io->hw_dif.blk_size;
        io->iparam.fcp_ini.timeout = io->timeout;
        io->iparam.fcp_ini.first_burst = first_burst;

        return ocs_scsi_io_dispatch(io, ocs_initiator_io_cb);
}

/**
 * @ingroup scsi_api_base
 * @brief Callback for an aborted IO.
 *
 * @par Description
 * Callback function invoked upon completion of an IO abort request.
 *
 * @param hio HW IO context.
 * @param rnode Remote node.
 * @param len Response length.
 * @param status Completion status.
 * @param ext_status Extended completion status.
 * @param arg Application-specific callback, usually IO context.

 * @return Returns 0 on success, or a negative error code value on failure.
 */

static int32_t
ocs_scsi_abort_io_cb(struct ocs_hw_io_s *hio, ocs_remote_node_t *rnode, uint32_t len, int32_t status,
        uint32_t ext_status, void *arg)
{
        ocs_io_t *io = arg;
        ocs_t *ocs;
        ocs_scsi_io_status_e scsi_status = OCS_SCSI_STATUS_GOOD;

        ocs_assert(io, -1);
        ocs_assert(ocs_io_busy(io), -1);
        ocs_assert(io->ocs, -1);
        ocs_assert(io->io_to_abort, -1);
        ocs = io->ocs;

        ocs_log_debug(ocs, "status %d ext %d\n", status, ext_status);

        /* done with IO to abort */
        ocs_ref_put(&io->io_to_abort->ref); /* ocs_ref_get(): ocs_scsi_send_tmf() */

        ocs_scsi_io_free_ovfl(io);

        switch (status) {
        case SLI4_FC_WCQE_STATUS_SUCCESS:
                scsi_status = OCS_SCSI_STATUS_GOOD;
                break;
        case SLI4_FC_WCQE_STATUS_LOCAL_REJECT:
                if (ext_status == SLI4_FC_LOCAL_REJECT_ABORT_REQUESTED) {
                        scsi_status = OCS_SCSI_STATUS_ABORTED;
                } else if (ext_status == SLI4_FC_LOCAL_REJECT_NO_XRI) {
                        scsi_status = OCS_SCSI_STATUS_NO_IO;
                } else if (ext_status == SLI4_FC_LOCAL_REJECT_ABORT_IN_PROGRESS) {
                        scsi_status = OCS_SCSI_STATUS_ABORT_IN_PROGRESS;
                } else {
                        ocs_log_test(ocs, "Unhandled local reject 0x%x/0x%x\n", status, ext_status);
                        scsi_status = OCS_SCSI_STATUS_ERROR;
                }
                break;
        default:
                scsi_status = OCS_SCSI_STATUS_ERROR;
                break;
        }

        if (io->scsi_ini_cb) {
                (*io->scsi_ini_cb)(io, scsi_status, NULL, 0, io->scsi_ini_cb_arg);
        } else {
                ocs_scsi_io_free(io);
        }

        ocs_scsi_check_pending(ocs);
        return 0;
}

/**
 * @ingroup scsi_api_base
 * @brief Return SCSI API integer valued property.
 *
 * @par Description
 * This function is called by a target-server or initiator-client to
 * retrieve an integer valued property.
 *
 * @param ocs Pointer to the ocs.
 * @param prop Property value to return.
 *
 * @return Returns a value, or 0 if invalid property was requested.
 */
uint32_t
ocs_scsi_get_property(ocs_t *ocs, ocs_scsi_property_e prop)
{
        ocs_xport_t *xport = ocs->xport;
        uint32_t        val;

        switch (prop) {
        case OCS_SCSI_MAX_SGE:
                if (0 == ocs_hw_get(&ocs->hw, OCS_HW_MAX_SGE, &val)) {
                        return val;
                }
                break;
        case OCS_SCSI_MAX_SGL:
                if (ocs->ctrlmask & OCS_CTRLMASK_TEST_CHAINED_SGLS) {
                        /*
                         * If chain SGL test-mode is enabled, the number of HW SGEs
                         * has been limited; report back original max.
                         */
                        return (OCS_FC_MAX_SGL);
                }
                if (0 == ocs_hw_get(&ocs->hw, OCS_HW_N_SGL, &val)) {
                        return val;
                }
                break;
        case OCS_SCSI_MAX_IOS:
                return ocs_io_pool_allocated(xport->io_pool);
        case OCS_SCSI_DIF_CAPABLE:
                if (0 == ocs_hw_get(&ocs->hw, OCS_HW_DIF_CAPABLE, &val)) {
                        return val;
                }
                break;
        case OCS_SCSI_MAX_FIRST_BURST:
                return 0;
        case OCS_SCSI_DIF_MULTI_SEPARATE:
                if (ocs_hw_get(&ocs->hw, OCS_HW_DIF_MULTI_SEPARATE, &val) == 0) {
                        return val;
                }
                break;
        case OCS_SCSI_ENABLE_TASK_SET_FULL:
                /* Return FALSE if we are send frame capable */
                if (ocs_hw_get(&ocs->hw, OCS_HW_SEND_FRAME_CAPABLE, &val) == 0) {
                        return ! val;
                }
                break;
        default:
                break;
        }

        ocs_log_debug(ocs, "invalid property request %d\n", prop);
        return 0;
}

/**
 * @ingroup scsi_api_base
 * @brief Return a property pointer.
 *
 * @par Description
 * This function is called by a target-server or initiator-client to
 * retrieve a pointer to the requested property.
 *
 * @param ocs Pointer to the ocs.
 * @param prop Property value to return.
 *
 * @return Returns pointer to the requested property, or NULL otherwise.
 */
void *ocs_scsi_get_property_ptr(ocs_t *ocs, ocs_scsi_property_e prop)
{
        void *rc = NULL;

        switch (prop) {
        case OCS_SCSI_WWNN:
                rc = ocs_hw_get_ptr(&ocs->hw, OCS_HW_WWN_NODE);
                break;
        case OCS_SCSI_WWPN:
                rc = ocs_hw_get_ptr(&ocs->hw, OCS_HW_WWN_PORT);
                break;
        case OCS_SCSI_PORTNUM:
                rc = ocs_hw_get_ptr(&ocs->hw, OCS_HW_PORTNUM);
                break;
        case OCS_SCSI_BIOS_VERSION_STRING:
                rc = ocs_hw_get_ptr(&ocs->hw, OCS_HW_BIOS_VERSION_STRING);
                break;
        case OCS_SCSI_SERIALNUMBER:
        {
                uint8_t *pvpd;
                uint32_t vpd_len;

                if (ocs_hw_get(&ocs->hw, OCS_HW_VPD_LEN, &vpd_len)) {
                        ocs_log_test(ocs, "Can't get VPD length\n");
                        rc = "\012sn-unknown";
                        break;
                }

                pvpd = ocs_hw_get_ptr(&ocs->hw, OCS_HW_VPD);
                if (pvpd) {
                        rc = ocs_find_vpd(pvpd, vpd_len, "SN");
                }

                if (rc == NULL ||
                    ocs_strlen(rc) == 0) {
                        /* Note: VPD is missing, using wwnn for serial number */
                        scsi_log(ocs, "Note: VPD is missing, using wwnn for serial number\n");
                        /* Use the last 32 bits of the WWN */
                        if ((ocs == NULL) || (ocs->domain == NULL) || (ocs->domain->sport == NULL)) {
                                rc = "\011(Unknown)";
                        } else {
                                rc = &ocs->domain->sport->wwnn_str[8];
                        }
                }
                break;
        }
        case OCS_SCSI_PARTNUMBER:
        {
                uint8_t *pvpd;
                uint32_t vpd_len;

                if (ocs_hw_get(&ocs->hw, OCS_HW_VPD_LEN, &vpd_len)) {
                        ocs_log_test(ocs, "Can't get VPD length\n");
                        rc = "\012pn-unknown";
                        break;
                }
                pvpd = ocs_hw_get_ptr(&ocs->hw, OCS_HW_VPD);
                if (pvpd) {
                        rc = ocs_find_vpd(pvpd, vpd_len, "PN");
                        if (rc == NULL) {
                                rc = "\012pn-unknown";
                        }
                } else {
                        rc = "\012pn-unknown";
                }
                break;
        }
        default:
                break;
        }

        if (rc == NULL) {
                ocs_log_debug(ocs, "invalid property request %d\n", prop);
        }
        return rc;
}

/**
 * @ingroup scsi_api_base
 * @brief Notify that delete initiator is complete.
 *
 * @par Description
 * Sent by the target-server to notify the base driver that the work started from
 * ocs_scsi_del_initiator() is now complete and that it is safe for the node to
 * release the rest of its resources.
 *
 * @param node Pointer to the node.
 *
 * @return None.
 */
void
ocs_scsi_del_initiator_complete(ocs_node_t *node)
{
        /* Notify the node to resume */
        ocs_node_post_event(node, OCS_EVT_NODE_DEL_INI_COMPLETE, NULL);
}

/**
 * @ingroup scsi_api_base
 * @brief Notify that delete target is complete.
 *
 * @par Description
 * Sent by the initiator-client to notify the base driver that the work started from
 * ocs_scsi_del_target() is now complete and that it is safe for the node to
 * release the rest of its resources.
 *
 * @param node Pointer to the node.
 *
 * @return None.
 */
void
ocs_scsi_del_target_complete(ocs_node_t *node)
{
        /* Notify the node to resume */
        ocs_node_post_event(node, OCS_EVT_NODE_DEL_TGT_COMPLETE, NULL);
}

/**
 * @brief Update transferred count
 *
 * @par Description
 * Updates io->transferred, as required when using first burst, when the amount
 * of first burst data processed differs from the amount of first burst
 * data received.
 *
 * @param io Pointer to the io object.
 * @param transferred Number of bytes transferred out of first burst buffers.
 *
 * @return None.
 */
void
ocs_scsi_update_first_burst_transferred(ocs_io_t *io, uint32_t transferred)
{
        io->transferred = transferred;
}

/**
 * @brief Register bounce callback for multi-threading.
 *
 * @par Description
 * Register the back end bounce function.
 *
 * @param ocs Pointer to device object.
 * @param fctn Function pointer of bounce function.
 *
 * @return None.
 */
void
ocs_scsi_register_bounce(ocs_t *ocs, void(*fctn)(void(*fctn)(void *arg), void *arg, uint32_t s_id, uint32_t d_id,
                                                 uint32_t ox_id))
{
        ocs_hw_rtn_e rc;

        rc = ocs_hw_callback(&ocs->hw, OCS_HW_CB_BOUNCE, fctn, NULL);
        if (rc) {
                ocs_log_test(ocs, "ocs_hw_callback(OCS_HW_CB_BOUNCE) failed: %d\n", rc);
        }
}