FreeBSD/Linux Kernel Cross Reference
sys/dev/ocs_fc/ocs_scsi.c

     /*-
      * 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.
     *
     * $FreeBSD$
     */
    
    /**
     * @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_TARGET_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, "Inavlid 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_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);
          }
  }

Cache object: 3ad89713a6ecd68638d5d6fe9b7a5943