/* cxgb3i_iscsi.c: Chelsio S3xx iSCSI driver.
 *
 * Copyright (c) 2008 Chelsio Communications, Inc.
 * Copyright (c) 2008 Mike Christie
 * Copyright (c) 2008 Red Hat, Inc.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation.
 *
 * Written by: Karen Xie (kxie@chelsio.com)
 */

#include <linux/inet.h>
#include <linux/crypto.h>
#include <linux/if_vlan.h>
#include <net/dst.h>
#include <net/tcp.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi.h>
#include <scsi/iscsi_proto.h>
#include <scsi/libiscsi.h>
#include <scsi/scsi_transport_iscsi.h>

#include "cxgb3i.h"
#include "cxgb3i_pdu.h"

#ifdef __DEBUG_CXGB3I_TAG__
#define cxgb3i_tag_debug        cxgb3i_log_debug
#else
#define cxgb3i_tag_debug(fmt...)
#endif

#ifdef __DEBUG_CXGB3I_API__
#define cxgb3i_api_debug        cxgb3i_log_debug
#else
#define cxgb3i_api_debug(fmt...)
#endif

/*
 * align pdu size to multiple of 512 for better performance
 */
#define align_pdu_size(n) do { n = (n) & (~511); } while (0)

static struct scsi_transport_template *cxgb3i_scsi_transport;
static struct scsi_host_template cxgb3i_host_template;
static struct iscsi_transport cxgb3i_iscsi_transport;
static unsigned char sw_tag_idx_bits;
static unsigned char sw_tag_age_bits;

static LIST_HEAD(cxgb3i_snic_list);
static DEFINE_RWLOCK(cxgb3i_snic_rwlock);

/**
 * cxgb3i_adpater_find_by_tdev - find the cxgb3i_adapter structure via t3cdev
 * @tdev: t3cdev pointer
 */
struct cxgb3i_adapter *cxgb3i_adapter_find_by_tdev(struct t3cdev *tdev)
{
        struct cxgb3i_adapter *snic;

        read_lock(&cxgb3i_snic_rwlock);
        list_for_each_entry(snic, &cxgb3i_snic_list, list_head) {
                if (snic->tdev == tdev) {
                        read_unlock(&cxgb3i_snic_rwlock);
                        return snic;
                }
        }
        read_unlock(&cxgb3i_snic_rwlock);
        return NULL;
}

static inline int adapter_update(struct cxgb3i_adapter *snic)
{
        cxgb3i_log_info("snic 0x%p, t3dev 0x%p, updating.\n",
                        snic, snic->tdev);
        return cxgb3i_adapter_ddp_info(snic->tdev, &snic->tag_format,
                                        &snic->tx_max_size,
                                        &snic->rx_max_size);
}

static int adapter_add(struct cxgb3i_adapter *snic)
{
        struct t3cdev *t3dev = snic->tdev;
        struct adapter *adapter = tdev2adap(t3dev);
        int i, err;

        snic->pdev = adapter->pdev;
        snic->tag_format.sw_bits = sw_tag_idx_bits + sw_tag_age_bits;

        err = cxgb3i_adapter_ddp_info(t3dev, &snic->tag_format,
                                    &snic->tx_max_size,
                                    &snic->rx_max_size);
        if (err < 0)
                return err;

        for_each_port(adapter, i) {
                snic->hba[i] = cxgb3i_hba_host_add(snic, adapter->port[i]);
                if (!snic->hba[i])
                        return -EINVAL;
        }
        snic->hba_cnt = adapter->params.nports;

        /* add to the list */
        write_lock(&cxgb3i_snic_rwlock);
        list_add_tail(&snic->list_head, &cxgb3i_snic_list);
        write_unlock(&cxgb3i_snic_rwlock);

        cxgb3i_log_info("t3dev 0x%p open, snic 0x%p, %u scsi hosts added.\n",
                        t3dev, snic, snic->hba_cnt);
        return 0;
}

/**
 * cxgb3i_adapter_open - init a s3 adapter structure and any h/w settings
 * @t3dev: t3cdev adapter
 */
void cxgb3i_adapter_open(struct t3cdev *t3dev)
{
        struct cxgb3i_adapter *snic = cxgb3i_adapter_find_by_tdev(t3dev);
        int err;

        if (snic)
                err = adapter_update(snic);
        else {
                snic = kzalloc(sizeof(*snic), GFP_KERNEL);
                if (snic) {
                        spin_lock_init(&snic->lock);
                        snic->tdev = t3dev;
                        err = adapter_add(snic);
                } else
                        err = -ENOMEM;
        }

        if (err < 0) {
                cxgb3i_log_info("snic 0x%p, f 0x%x, t3dev 0x%p open, err %d.\n",
                                snic, snic ? snic->flags : 0, t3dev, err);
                if (snic) {
                        snic->flags &= ~CXGB3I_ADAPTER_FLAG_RESET;
                        cxgb3i_adapter_close(t3dev);
                }
        }
}

/**
 * cxgb3i_adapter_close - release the resources held and cleanup h/w settings
 * @t3dev: t3cdev adapter
 */
void cxgb3i_adapter_close(struct t3cdev *t3dev)
{
        struct cxgb3i_adapter *snic = cxgb3i_adapter_find_by_tdev(t3dev);
        int i;

        if (!snic || snic->flags & CXGB3I_ADAPTER_FLAG_RESET) {
                cxgb3i_log_info("t3dev 0x%p close, snic 0x%p, f 0x%x.\n",
                                t3dev, snic, snic ? snic->flags : 0);
                return;
        }

        /* remove from the list */
        write_lock(&cxgb3i_snic_rwlock);
        list_del(&snic->list_head);
        write_unlock(&cxgb3i_snic_rwlock);

        for (i = 0; i < snic->hba_cnt; i++) {
                if (snic->hba[i]) {
                        cxgb3i_hba_host_remove(snic->hba[i]);
                        snic->hba[i] = NULL;
                }
        }
        cxgb3i_log_info("t3dev 0x%p close, snic 0x%p, %u scsi hosts removed.\n",
                        t3dev, snic, snic->hba_cnt);
        kfree(snic);
}

/**
 * cxgb3i_hba_find_by_netdev - find the cxgb3i_hba structure via net_device
 * @t3dev: t3cdev adapter
 */
static struct cxgb3i_hba *cxgb3i_hba_find_by_netdev(struct net_device *ndev)
{
        struct cxgb3i_adapter *snic;
        int i;

        if (ndev->priv_flags & IFF_802_1Q_VLAN)
                ndev = vlan_dev_real_dev(ndev);

        read_lock(&cxgb3i_snic_rwlock);
        list_for_each_entry(snic, &cxgb3i_snic_list, list_head) {
                for (i = 0; i < snic->hba_cnt; i++) {
                        if (snic->hba[i]->ndev == ndev) {
                                read_unlock(&cxgb3i_snic_rwlock);
                                return snic->hba[i];
                        }
                }
        }
        read_unlock(&cxgb3i_snic_rwlock);
        return NULL;
}

/**
 * cxgb3i_hba_host_add - register a new host with scsi/iscsi
 * @snic: the cxgb3i adapter
 * @ndev: associated net_device
 */
struct cxgb3i_hba *cxgb3i_hba_host_add(struct cxgb3i_adapter *snic,
                                       struct net_device *ndev)
{
        struct cxgb3i_hba *hba;
        struct Scsi_Host *shost;
        int err;

        shost = iscsi_host_alloc(&cxgb3i_host_template,
                                 sizeof(struct cxgb3i_hba), 1);
        if (!shost) {
                cxgb3i_log_info("snic 0x%p, ndev 0x%p, host_alloc failed.\n",
                                snic, ndev);
                return NULL;
        }

        shost->transportt = cxgb3i_scsi_transport;
        shost->max_lun = CXGB3I_MAX_LUN;
        shost->max_id = CXGB3I_MAX_TARGET;
        shost->max_channel = 0;
        shost->max_cmd_len = 16;

        hba = iscsi_host_priv(shost);
        hba->snic = snic;
        hba->ndev = ndev;
        hba->shost = shost;

        pci_dev_get(snic->pdev);
        err = iscsi_host_add(shost, &snic->pdev->dev);
        if (err) {
                cxgb3i_log_info("snic 0x%p, ndev 0x%p, host_add failed.\n",
                                snic, ndev);
                goto pci_dev_put;
        }

        cxgb3i_api_debug("shost 0x%p, hba 0x%p, no %u.\n",
                         shost, hba, shost->host_no);

        return hba;

pci_dev_put:
        pci_dev_put(snic->pdev);
        scsi_host_put(shost);
        return NULL;
}

/**
 * cxgb3i_hba_host_remove - de-register the host with scsi/iscsi
 * @hba: the cxgb3i hba
 */
void cxgb3i_hba_host_remove(struct cxgb3i_hba *hba)
{
        cxgb3i_api_debug("shost 0x%p, hba 0x%p, no %u.\n",
                         hba->shost, hba, hba->shost->host_no);
        iscsi_host_remove(hba->shost);
        pci_dev_put(hba->snic->pdev);
        iscsi_host_free(hba->shost);
}

/**
 * cxgb3i_ep_connect - establish TCP connection to target portal
 * @shost:              scsi host to use
 * @dst_addr:           target IP address
 * @non_blocking:       blocking or non-blocking call
 *
 * Initiates a TCP/IP connection to the dst_addr
 */
static struct iscsi_endpoint *cxgb3i_ep_connect(struct Scsi_Host *shost,
                                                struct sockaddr *dst_addr,
                                                int non_blocking)
{
        struct iscsi_endpoint *ep;
        struct cxgb3i_endpoint *cep;
        struct cxgb3i_hba *hba = NULL;
        struct s3_conn *c3cn = NULL;
        int err = 0;

        if (shost)
                hba = iscsi_host_priv(shost);

        cxgb3i_api_debug("shost 0x%p, hba 0x%p.\n", shost, hba);

        c3cn = cxgb3i_c3cn_create();
        if (!c3cn) {
                cxgb3i_log_info("ep connect OOM.\n");
                err = -ENOMEM;
                goto release_conn;
        }

        err = cxgb3i_c3cn_connect(hba ? hba->ndev : NULL, c3cn,
                                 (struct sockaddr_in *)dst_addr);
        if (err < 0) {
                cxgb3i_log_info("ep connect failed.\n");
                goto release_conn;
        }

        hba = cxgb3i_hba_find_by_netdev(c3cn->dst_cache->dev);
        if (!hba) {
                err = -ENOSPC;
                cxgb3i_log_info("NOT going through cxgbi device.\n");
                goto release_conn;
        }

        if (shost && hba != iscsi_host_priv(shost)) {
                err = -ENOSPC;
                cxgb3i_log_info("Could not connect through request host%u\n",
                                shost->host_no);
                goto release_conn;
        }

        if (c3cn_is_closing(c3cn)) {
                err = -ENOSPC;
                cxgb3i_log_info("ep connect unable to connect.\n");
                goto release_conn;
        }

        ep = iscsi_create_endpoint(sizeof(*cep));
        if (!ep) {
                err = -ENOMEM;
                cxgb3i_log_info("iscsi alloc ep, OOM.\n");
                goto release_conn;
        }
        cep = ep->dd_data;
        cep->c3cn = c3cn;
        cep->hba = hba;

        cxgb3i_api_debug("ep 0x%p, 0x%p, c3cn 0x%p, hba 0x%p.\n",
                          ep, cep, c3cn, hba);
        return ep;

release_conn:
        cxgb3i_api_debug("conn 0x%p failed, release.\n", c3cn);
        if (c3cn)
                cxgb3i_c3cn_release(c3cn);
        return ERR_PTR(err);
}

/**
 * cxgb3i_ep_poll - polls for TCP connection establishement
 * @ep:         TCP connection (endpoint) handle
 * @timeout_ms: timeout value in milli secs
 *
 * polls for TCP connect request to complete
 */
static int cxgb3i_ep_poll(struct iscsi_endpoint *ep, int timeout_ms)
{
        struct cxgb3i_endpoint *cep = ep->dd_data;
        struct s3_conn *c3cn = cep->c3cn;

        if (!c3cn_is_established(c3cn))
                return 0;
        cxgb3i_api_debug("ep 0x%p, c3cn 0x%p established.\n", ep, c3cn);
        return 1;
}

/**
 * cxgb3i_ep_disconnect - teardown TCP connection
 * @ep:         TCP connection (endpoint) handle
 *
 * teardown TCP connection
 */
static void cxgb3i_ep_disconnect(struct iscsi_endpoint *ep)
{
        struct cxgb3i_endpoint *cep = ep->dd_data;
        struct cxgb3i_conn *cconn = cep->cconn;

        cxgb3i_api_debug("ep 0x%p, cep 0x%p.\n", ep, cep);

        if (cconn && cconn->conn) {
                /*
                 * stop the xmit path so the xmit_pdu function is
                 * not being called
                 */
                iscsi_suspend_tx(cconn->conn);

                write_lock_bh(&cep->c3cn->callback_lock);
                cep->c3cn->user_data = NULL;
                cconn->cep = NULL;
                write_unlock_bh(&cep->c3cn->callback_lock);
        }

        cxgb3i_api_debug("ep 0x%p, cep 0x%p, release c3cn 0x%p.\n",
                         ep, cep, cep->c3cn);
        cxgb3i_c3cn_release(cep->c3cn);
        iscsi_destroy_endpoint(ep);
}

/**
 * cxgb3i_session_create - create a new iscsi session
 * @cmds_max:           max # of commands
 * @qdepth:             scsi queue depth
 * @initial_cmdsn:      initial iscsi CMDSN for this session
 *
 * Creates a new iSCSI session
 */
static struct iscsi_cls_session *
cxgb3i_session_create(struct iscsi_endpoint *ep, u16 cmds_max, u16 qdepth,
                      u32 initial_cmdsn)
{
        struct cxgb3i_endpoint *cep;
        struct cxgb3i_hba *hba;
        struct Scsi_Host *shost;
        struct iscsi_cls_session *cls_session;
        struct iscsi_session *session;

        if (!ep) {
                cxgb3i_log_error("%s, missing endpoint.\n", __func__);
                return NULL;
        }

        cep = ep->dd_data;
        hba = cep->hba;
        shost = hba->shost;
        cxgb3i_api_debug("ep 0x%p, cep 0x%p, hba 0x%p.\n", ep, cep, hba);
        BUG_ON(hba != iscsi_host_priv(shost));

        cls_session = iscsi_session_setup(&cxgb3i_iscsi_transport, shost,
                                          cmds_max, 0,
                                          sizeof(struct iscsi_tcp_task) +
                                          sizeof(struct cxgb3i_task_data),
                                          initial_cmdsn, ISCSI_MAX_TARGET);
        if (!cls_session)
                return NULL;
        session = cls_session->dd_data;
        if (iscsi_tcp_r2tpool_alloc(session))
                goto remove_session;

        return cls_session;

remove_session:
        iscsi_session_teardown(cls_session);
        return NULL;
}

/**
 * cxgb3i_session_destroy - destroys iscsi session
 * @cls_session:        pointer to iscsi cls session
 *
 * Destroys an iSCSI session instance and releases its all resources held
 */
static void cxgb3i_session_destroy(struct iscsi_cls_session *cls_session)
{
        cxgb3i_api_debug("sess 0x%p.\n", cls_session);
        iscsi_tcp_r2tpool_free(cls_session->dd_data);
        iscsi_session_teardown(cls_session);
}

/**
 * cxgb3i_conn_max_xmit_dlength -- calc the max. xmit pdu segment size
 * @conn: iscsi connection
 * check the max. xmit pdu payload, reduce it if needed
 */
static inline int cxgb3i_conn_max_xmit_dlength(struct iscsi_conn *conn)

{
        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
        struct cxgb3i_conn *cconn = tcp_conn->dd_data;
        unsigned int max = max(512 * MAX_SKB_FRAGS, SKB_TX_HEADROOM);

        max = min(cconn->hba->snic->tx_max_size, max);
        if (conn->max_xmit_dlength)
                conn->max_xmit_dlength = min(conn->max_xmit_dlength, max);
        else
                conn->max_xmit_dlength = max;
        align_pdu_size(conn->max_xmit_dlength);
        cxgb3i_api_debug("conn 0x%p, max xmit %u.\n",
                         conn, conn->max_xmit_dlength);
        return 0;
}

/**
 * cxgb3i_conn_max_recv_dlength -- check the max. recv pdu segment size
 * @conn: iscsi connection
 * return 0 if the value is valid, < 0 otherwise.
 */
static inline int cxgb3i_conn_max_recv_dlength(struct iscsi_conn *conn)
{
        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
        struct cxgb3i_conn *cconn = tcp_conn->dd_data;
        unsigned int max = cconn->hba->snic->rx_max_size;

        align_pdu_size(max);
        if (conn->max_recv_dlength) {
                if (conn->max_recv_dlength > max) {
                        cxgb3i_log_error("MaxRecvDataSegmentLength %u too big."
                                         " Need to be <= %u.\n",
                                         conn->max_recv_dlength, max);
                        return -EINVAL;
                }
                conn->max_recv_dlength = min(conn->max_recv_dlength, max);
                align_pdu_size(conn->max_recv_dlength);
        } else
                conn->max_recv_dlength = max;
        cxgb3i_api_debug("conn 0x%p, max recv %u.\n",
                         conn, conn->max_recv_dlength);
        return 0;
}

/**
 * cxgb3i_conn_create - create iscsi connection instance
 * @cls_session:        pointer to iscsi cls session
 * @cid:                iscsi cid
 *
 * Creates a new iSCSI connection instance for a given session
 */
static struct iscsi_cls_conn *cxgb3i_conn_create(struct iscsi_cls_session
                                                 *cls_session, u32 cid)
{
        struct iscsi_cls_conn *cls_conn;
        struct iscsi_conn *conn;
        struct iscsi_tcp_conn *tcp_conn;
        struct cxgb3i_conn *cconn;

        cxgb3i_api_debug("sess 0x%p, cid %u.\n", cls_session, cid);

        cls_conn = iscsi_tcp_conn_setup(cls_session, sizeof(*cconn), cid);
        if (!cls_conn)
                return NULL;
        conn = cls_conn->dd_data;
        tcp_conn = conn->dd_data;
        cconn = tcp_conn->dd_data;

        cconn->conn = conn;
        return cls_conn;
}

/**
 * cxgb3i_conn_bind - binds iscsi sess, conn and endpoint together
 * @cls_session:        pointer to iscsi cls session
 * @cls_conn:           pointer to iscsi cls conn
 * @transport_eph:      64-bit EP handle
 * @is_leading:         leading connection on this session?
 *
 * Binds together an iSCSI session, an iSCSI connection and a
 *      TCP connection. This routine returns error code if the TCP
 *      connection does not belong on the device iSCSI sess/conn is bound
 */

static int cxgb3i_conn_bind(struct iscsi_cls_session *cls_session,
                            struct iscsi_cls_conn *cls_conn,
                            u64 transport_eph, int is_leading)
{
        struct iscsi_conn *conn = cls_conn->dd_data;
        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
        struct cxgb3i_conn *cconn = tcp_conn->dd_data;
        struct cxgb3i_adapter *snic;
        struct iscsi_endpoint *ep;
        struct cxgb3i_endpoint *cep;
        struct s3_conn *c3cn;
        int err;

        ep = iscsi_lookup_endpoint(transport_eph);
        if (!ep)
                return -EINVAL;

        /* setup ddp pagesize */
        cep = ep->dd_data;
        c3cn = cep->c3cn;
        snic = cep->hba->snic;
        err = cxgb3i_setup_conn_host_pagesize(snic->tdev, c3cn->tid, 0);
        if (err < 0)
                return err;

        cxgb3i_api_debug("ep 0x%p, cls sess 0x%p, cls conn 0x%p.\n",
                         ep, cls_session, cls_conn);

        err = iscsi_conn_bind(cls_session, cls_conn, is_leading);
        if (err)
                return -EINVAL;

        /* calculate the tag idx bits needed for this conn based on cmds_max */
        cconn->task_idx_bits = (__ilog2_u32(conn->session->cmds_max - 1)) + 1;
        cxgb3i_api_debug("session cmds_max 0x%x, bits %u.\n",
                         conn->session->cmds_max, cconn->task_idx_bits);

        read_lock(&c3cn->callback_lock);
        c3cn->user_data = conn;
        cconn->hba = cep->hba;
        cconn->cep = cep;
        cep->cconn = cconn;
        read_unlock(&c3cn->callback_lock);

        cxgb3i_conn_max_xmit_dlength(conn);
        cxgb3i_conn_max_recv_dlength(conn);

        spin_lock_bh(&conn->session->lock);
        sprintf(conn->portal_address, NIPQUAD_FMT,
                NIPQUAD(c3cn->daddr.sin_addr.s_addr));
        conn->portal_port = ntohs(c3cn->daddr.sin_port);
        spin_unlock_bh(&conn->session->lock);

        /* init recv engine */
        iscsi_tcp_hdr_recv_prep(tcp_conn);

        return 0;
}

/**
 * cxgb3i_conn_get_param - return iscsi connection parameter to caller
 * @cls_conn:   pointer to iscsi cls conn
 * @param:      parameter type identifier
 * @buf:        buffer pointer
 *
 * returns iSCSI connection parameters
 */
static int cxgb3i_conn_get_param(struct iscsi_cls_conn *cls_conn,
                                 enum iscsi_param param, char *buf)
{
        struct iscsi_conn *conn = cls_conn->dd_data;
        int len;

        cxgb3i_api_debug("cls_conn 0x%p, param %d.\n", cls_conn, param);

        switch (param) {
        case ISCSI_PARAM_CONN_PORT:
                spin_lock_bh(&conn->session->lock);
                len = sprintf(buf, "%hu\n", conn->portal_port);
                spin_unlock_bh(&conn->session->lock);
                break;
        case ISCSI_PARAM_CONN_ADDRESS:
                spin_lock_bh(&conn->session->lock);
                len = sprintf(buf, "%s\n", conn->portal_address);
                spin_unlock_bh(&conn->session->lock);
                break;
        default:
                return iscsi_conn_get_param(cls_conn, param, buf);
        }

        return len;
}

/**
 * cxgb3i_conn_set_param - set iscsi connection parameter
 * @cls_conn:   pointer to iscsi cls conn
 * @param:      parameter type identifier
 * @buf:        buffer pointer
 * @buflen:     buffer length
 *
 * set iSCSI connection parameters
 */
static int cxgb3i_conn_set_param(struct iscsi_cls_conn *cls_conn,
                                 enum iscsi_param param, char *buf, int buflen)
{
        struct iscsi_conn *conn = cls_conn->dd_data;
        struct iscsi_session *session = conn->session;
        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
        struct cxgb3i_conn *cconn = tcp_conn->dd_data;
        struct cxgb3i_adapter *snic = cconn->hba->snic;
        struct s3_conn *c3cn = cconn->cep->c3cn;
        int value, err = 0;

        switch (param) {
        case ISCSI_PARAM_HDRDGST_EN:
                err = iscsi_set_param(cls_conn, param, buf, buflen);
                if (!err && conn->hdrdgst_en)
                        err = cxgb3i_setup_conn_digest(snic->tdev, c3cn->tid,
                                                        conn->hdrdgst_en,
                                                        conn->datadgst_en, 0);
                break;
        case ISCSI_PARAM_DATADGST_EN:
                err = iscsi_set_param(cls_conn, param, buf, buflen);
                if (!err && conn->datadgst_en)
                        err = cxgb3i_setup_conn_digest(snic->tdev, c3cn->tid,
                                                        conn->hdrdgst_en,
                                                        conn->datadgst_en, 0);
                break;
        case ISCSI_PARAM_MAX_R2T:
                sscanf(buf, "%d", &value);
                if (value <= 0 || !is_power_of_2(value))
                        return -EINVAL;
                if (session->max_r2t == value)
                        break;
                iscsi_tcp_r2tpool_free(session);
                err = iscsi_set_param(cls_conn, param, buf, buflen);
                if (!err && iscsi_tcp_r2tpool_alloc(session))
                        return -ENOMEM;
        case ISCSI_PARAM_MAX_RECV_DLENGTH:
                err = iscsi_set_param(cls_conn, param, buf, buflen);
                if (!err)
                        err = cxgb3i_conn_max_recv_dlength(conn);
                break;
        case ISCSI_PARAM_MAX_XMIT_DLENGTH:
                err = iscsi_set_param(cls_conn, param, buf, buflen);
                if (!err)
                        err = cxgb3i_conn_max_xmit_dlength(conn);
                break;
        default:
                return iscsi_set_param(cls_conn, param, buf, buflen);
        }
        return err;
}

/**
 * cxgb3i_host_set_param - configure host (adapter) related parameters
 * @shost:      scsi host pointer
 * @param:      parameter type identifier
 * @buf:        buffer pointer
 */
static int cxgb3i_host_set_param(struct Scsi_Host *shost,
                                 enum iscsi_host_param param,
                                 char *buf, int buflen)
{
        struct cxgb3i_hba *hba = iscsi_host_priv(shost);

        cxgb3i_api_debug("param %d, buf %s.\n", param, buf);

        switch (param) {
        case ISCSI_HOST_PARAM_IPADDRESS:
        {
                __be32 addr = in_aton(buf);
                cxgb3i_set_private_ipv4addr(hba->ndev, addr);
                return 0;
        }
        case ISCSI_HOST_PARAM_HWADDRESS:
        case ISCSI_HOST_PARAM_NETDEV_NAME:
                /* ignore */
                return 0;
        default:
                return iscsi_host_set_param(shost, param, buf, buflen);
        }
}

/**
 * cxgb3i_host_get_param - returns host (adapter) related parameters
 * @shost:      scsi host pointer
 * @param:      parameter type identifier
 * @buf:        buffer pointer
 */
static int cxgb3i_host_get_param(struct Scsi_Host *shost,
                                 enum iscsi_host_param param, char *buf)
{
        struct cxgb3i_hba *hba = iscsi_host_priv(shost);
        int len = 0;

        cxgb3i_api_debug("hba %s, param %d.\n", hba->ndev->name, param);

        switch (param) {
        case ISCSI_HOST_PARAM_HWADDRESS:
                len = sysfs_format_mac(buf, hba->ndev->dev_addr, 6);
                break;
        case ISCSI_HOST_PARAM_NETDEV_NAME:
                len = sprintf(buf, "%s\n", hba->ndev->name);
                break;
        case ISCSI_HOST_PARAM_IPADDRESS:
        {
                __be32 addr;

                addr = cxgb3i_get_private_ipv4addr(hba->ndev);
                len = sprintf(buf, NIPQUAD_FMT, NIPQUAD(addr));
                break;
        }
        default:
                return iscsi_host_get_param(shost, param, buf);
        }
        return len;
}

/**
 * cxgb3i_conn_get_stats - returns iSCSI stats
 * @cls_conn:   pointer to iscsi cls conn
 * @stats:      pointer to iscsi statistic struct
 */
static void cxgb3i_conn_get_stats(struct iscsi_cls_conn *cls_conn,
                                  struct iscsi_stats *stats)
{
        struct iscsi_conn *conn = cls_conn->dd_data;

        stats->txdata_octets = conn->txdata_octets;
        stats->rxdata_octets = conn->rxdata_octets;
        stats->scsicmd_pdus = conn->scsicmd_pdus_cnt;
        stats->dataout_pdus = conn->dataout_pdus_cnt;
        stats->scsirsp_pdus = conn->scsirsp_pdus_cnt;
        stats->datain_pdus = conn->datain_pdus_cnt;
        stats->r2t_pdus = conn->r2t_pdus_cnt;
        stats->tmfcmd_pdus = conn->tmfcmd_pdus_cnt;
        stats->tmfrsp_pdus = conn->tmfrsp_pdus_cnt;
        stats->digest_err = 0;
        stats->timeout_err = 0;
        stats->custom_length = 1;
        strcpy(stats->custom[0].desc, "eh_abort_cnt");
        stats->custom[0].value = conn->eh_abort_cnt;
}

/**
 * cxgb3i_parse_itt - get the idx and age bits from a given tag
 * @conn:       iscsi connection
 * @itt:        itt tag
 * @idx:        task index, filled in by this function
 * @age:        session age, filled in by this function
 */
static void cxgb3i_parse_itt(struct iscsi_conn *conn, itt_t itt,
                             int *idx, int *age)
{
        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
        struct cxgb3i_conn *cconn = tcp_conn->dd_data;
        struct cxgb3i_adapter *snic = cconn->hba->snic;
        u32 tag = ntohl((__force u32) itt);
        u32 sw_bits;

        sw_bits = cxgb3i_tag_nonrsvd_bits(&snic->tag_format, tag);
        if (idx)
                *idx = sw_bits & ((1 << cconn->task_idx_bits) - 1);
        if (age)
                *age = (sw_bits >> cconn->task_idx_bits) & ISCSI_AGE_MASK;

        cxgb3i_tag_debug("parse tag 0x%x/0x%x, sw 0x%x, itt 0x%x, age 0x%x.\n",
                         tag, itt, sw_bits, idx ? *idx : 0xFFFFF,
                         age ? *age : 0xFF);
}

/**
 * cxgb3i_reserve_itt - generate tag for a give task
 * @task: iscsi task
 * @hdr_itt: tag, filled in by this function
 * Set up ddp for scsi read tasks if possible.
 */
int cxgb3i_reserve_itt(struct iscsi_task *task, itt_t *hdr_itt)
{
        struct scsi_cmnd *sc = task->sc;
        struct iscsi_conn *conn = task->conn;
        struct iscsi_session *sess = conn->session;
        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
        struct cxgb3i_conn *cconn = tcp_conn->dd_data;
        struct cxgb3i_adapter *snic = cconn->hba->snic;
        struct cxgb3i_tag_format *tformat = &snic->tag_format;
        u32 sw_tag = (sess->age << cconn->task_idx_bits) | task->itt;
        u32 tag;
        int err = -EINVAL;

        if (sc &&
            (scsi_bidi_cmnd(sc) || sc->sc_data_direction == DMA_FROM_DEVICE) &&
            cxgb3i_sw_tag_usable(tformat, sw_tag)) {
                struct s3_conn *c3cn = cconn->cep->c3cn;
                struct cxgb3i_gather_list *gl;

                gl = cxgb3i_ddp_make_gl(scsi_in(sc)->length,
                                        scsi_in(sc)->table.sgl,
                                        scsi_in(sc)->table.nents,
                                        snic->pdev,
                                        GFP_ATOMIC);
                if (gl) {
                        tag = sw_tag;
                        err = cxgb3i_ddp_tag_reserve(snic->tdev, c3cn->tid,
                                                     tformat, &tag,
                                                     gl, GFP_ATOMIC);
                        if (err < 0)
                                cxgb3i_ddp_release_gl(gl, snic->pdev);
                }
        }

        if (err < 0)
                tag = cxgb3i_set_non_ddp_tag(tformat, sw_tag);
        /* the itt need to sent in big-endian order */
        *hdr_itt = (__force itt_t)htonl(tag);

        cxgb3i_tag_debug("new tag 0x%x/0x%x (itt 0x%x, age 0x%x).\n",
                         tag, *hdr_itt, task->itt, sess->age);
        return 0;
}

/**
 * cxgb3i_release_itt - release the tag for a given task
 * @task:       iscsi task
 * @hdr_itt:    tag
 * If the tag is a ddp tag, release the ddp setup
 */
void cxgb3i_release_itt(struct iscsi_task *task, itt_t hdr_itt)
{
        struct scsi_cmnd *sc = task->sc;
        struct iscsi_tcp_conn *tcp_conn = task->conn->dd_data;
        struct cxgb3i_conn *cconn = tcp_conn->dd_data;
        struct cxgb3i_adapter *snic = cconn->hba->snic;
        struct cxgb3i_tag_format *tformat = &snic->tag_format;
        u32 tag = ntohl((__force u32)hdr_itt);

        cxgb3i_tag_debug("release tag 0x%x.\n", tag);

        if (sc &&
            (scsi_bidi_cmnd(sc) || sc->sc_data_direction == DMA_FROM_DEVICE) &&
            cxgb3i_is_ddp_tag(tformat, tag))
                cxgb3i_ddp_tag_release(snic->tdev, tag);
}

/**
 * cxgb3i_host_template -- Scsi_Host_Template structure
 *      used when registering with the scsi mid layer
 */
static struct scsi_host_template cxgb3i_host_template = {
        .module                 = THIS_MODULE,
        .name                   = "Chelsio S3xx iSCSI Initiator",
        .proc_name              = "cxgb3i",
        .queuecommand           = iscsi_queuecommand,
        .change_queue_depth     = iscsi_change_queue_depth,
        .can_queue              = CXGB3I_SCSI_HOST_QDEPTH,
        .sg_tablesize           = SG_ALL,
        .max_sectors            = 0xFFFF,
        .cmd_per_lun            = ISCSI_DEF_CMD_PER_LUN,
        .eh_abort_handler       = iscsi_eh_abort,
        .eh_device_reset_handler = iscsi_eh_device_reset,
        .eh_target_reset_handler = iscsi_eh_target_reset,
        .target_alloc           = iscsi_target_alloc,
        .use_clustering         = DISABLE_CLUSTERING,
        .this_id                = -1,
};

static struct iscsi_transport cxgb3i_iscsi_transport = {
        .owner                  = THIS_MODULE,
        .name                   = "cxgb3i",
        .caps                   = CAP_RECOVERY_L0 | CAP_MULTI_R2T | CAP_HDRDGST
                                | CAP_DATADGST | CAP_DIGEST_OFFLOAD |
                                CAP_PADDING_OFFLOAD,
        .param_mask             = ISCSI_MAX_RECV_DLENGTH |
                                ISCSI_MAX_XMIT_DLENGTH |
                                ISCSI_HDRDGST_EN |
                                ISCSI_DATADGST_EN |
                                ISCSI_INITIAL_R2T_EN |
                                ISCSI_MAX_R2T |
                                ISCSI_IMM_DATA_EN |
                                ISCSI_FIRST_BURST |
                                ISCSI_MAX_BURST |
                                ISCSI_PDU_INORDER_EN |
                                ISCSI_DATASEQ_INORDER_EN |
                                ISCSI_ERL |
                                ISCSI_CONN_PORT |
                                ISCSI_CONN_ADDRESS |
                                ISCSI_EXP_STATSN |
                                ISCSI_PERSISTENT_PORT |
                                ISCSI_PERSISTENT_ADDRESS |
                                ISCSI_TARGET_NAME | ISCSI_TPGT |
                                ISCSI_USERNAME | ISCSI_PASSWORD |
                                ISCSI_USERNAME_IN | ISCSI_PASSWORD_IN |
                                ISCSI_FAST_ABORT | ISCSI_ABORT_TMO |
                                ISCSI_LU_RESET_TMO |
                                ISCSI_PING_TMO | ISCSI_RECV_TMO |
                                ISCSI_IFACE_NAME | ISCSI_INITIATOR_NAME,
        .host_param_mask        = ISCSI_HOST_HWADDRESS | ISCSI_HOST_IPADDRESS |
                        ISCSI_HOST_INITIATOR_NAME | ISCSI_HOST_NETDEV_NAME,
        .get_host_param         = cxgb3i_host_get_param,
        .set_host_param         = cxgb3i_host_set_param,
        /* session management */
        .create_session         = cxgb3i_session_create,
        .destroy_session        = cxgb3i_session_destroy,
        .get_session_param      = iscsi_session_get_param,
        /* connection management */
        .create_conn            = cxgb3i_conn_create,
        .bind_conn              = cxgb3i_conn_bind,
        .destroy_conn           = iscsi_tcp_conn_teardown,
        .start_conn             = iscsi_conn_start,
        .stop_conn              = iscsi_conn_stop,
        .get_conn_param         = cxgb3i_conn_get_param,
        .set_param              = cxgb3i_conn_set_param,
        .get_stats              = cxgb3i_conn_get_stats,
        /* pdu xmit req. from user space */
        .send_pdu               = iscsi_conn_send_pdu,
        /* task */
        .init_task              = iscsi_tcp_task_init,
        .xmit_task              = iscsi_tcp_task_xmit,
        .cleanup_task           = cxgb3i_conn_cleanup_task,

        /* pdu */
        .alloc_pdu              = cxgb3i_conn_alloc_pdu,
        .init_pdu               = cxgb3i_conn_init_pdu,
        .xmit_pdu               = cxgb3i_conn_xmit_pdu,
        .parse_pdu_itt          = cxgb3i_parse_itt,

        /* TCP connect/disconnect */
        .ep_connect             = cxgb3i_ep_connect,
        .ep_poll                = cxgb3i_ep_poll,
        .ep_disconnect          = cxgb3i_ep_disconnect,
        /* Error recovery timeout call */
        .session_recovery_timedout = iscsi_session_recovery_timedout,
};

int cxgb3i_iscsi_init(void)
{
        sw_tag_idx_bits = (__ilog2_u32(ISCSI_ITT_MASK)) + 1;
        sw_tag_age_bits = (__ilog2_u32(ISCSI_AGE_MASK)) + 1;
        cxgb3i_log_info("tag itt 0x%x, %u bits, age 0x%x, %u bits.\n",
                        ISCSI_ITT_MASK, sw_tag_idx_bits,
                        ISCSI_AGE_MASK, sw_tag_age_bits);

        cxgb3i_scsi_transport =
            iscsi_register_transport(&cxgb3i_iscsi_transport);
        if (!cxgb3i_scsi_transport) {
                cxgb3i_log_error("Could not register cxgb3i transport.\n");
                return -ENODEV;
        }
        cxgb3i_api_debug("cxgb3i transport 0x%p.\n", cxgb3i_scsi_transport);
        return 0;
}

void cxgb3i_iscsi_cleanup(void)
{

        if (cxgb3i_scsi_transport) {
                cxgb3i_api_debug("cxgb3i transport 0x%p.\n",
                                 cxgb3i_scsi_transport);
                iscsi_unregister_transport(&cxgb3i_iscsi_transport);
        }
}