ibmvstgt.c

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/*
 * IBM eServer i/pSeries Virtual SCSI Target Driver
 * Copyright (C) 2003-2005 Dave Boutcher ([email protected]) IBM Corp.
 *             Santiago Leon ([email protected]) IBM Corp.
 *             Linda Xie ([email protected]) IBM Corp.
 *
 * Copyright (C) 2005-2006 FUJITA Tomonori <[email protected]>
 *
 * 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; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 * USA
 */
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <scsi/scsi.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_transport_srp.h>
#include <scsi/scsi_tgt.h>
#include <scsi/libsrp.h>
#include <asm/hvcall.h>
#include <asm/iommu.h>
#include <asm/prom.h>
#include <asm/vio.h>

#include "ibmvscsi.h"

#define INITIAL_SRP_LIMIT   16
#define DEFAULT_MAX_SECTORS 256

#define TGT_NAME    "ibmvstgt"

/*
 * Hypervisor calls.
 */
#define h_copy_rdma(l, sa, sb, da, db) \
            plpar_hcall_norets(H_COPY_RDMA, l, sa, sb, da, db)
#define h_send_crq(ua, l, h) \
            plpar_hcall_norets(H_SEND_CRQ, ua, l, h)
#define h_reg_crq(ua, tok, sz)\
            plpar_hcall_norets(H_REG_CRQ, ua, tok, sz);
#define h_free_crq(ua) \
            plpar_hcall_norets(H_FREE_CRQ, ua);

/* tmp - will replace with SCSI logging stuff */
#define eprintk(fmt, args...)                   \
do {                                \
    printk("%s(%d) " fmt, __func__, __LINE__, ##args);  \
} while (0)
/* #define dprintk eprintk */
#define dprintk(fmt, args...)

struct vio_port {
    struct vio_dev *dma_dev;

    struct crq_queue crq_queue;
    struct work_struct crq_work;

    unsigned long liobn;
    unsigned long riobn;
    struct srp_target *target;

    struct srp_rport *rport;
};

static struct workqueue_struct *vtgtd;
static struct scsi_transport_template *ibmvstgt_transport_template;

/*
 * These are fixed for the system and come from the Open Firmware device tree.
 * We just store them here to save getting them every time.
 */
static char system_id[64] = "";
static char partition_name[97] = "UNKNOWN";
static unsigned int partition_number = -1;

static struct vio_port *target_to_port(struct srp_target *target)
{
    return (struct vio_port *) target->ldata;
}

static inline union viosrp_iu *vio_iu(struct iu_entry *iue)
{
    return (union viosrp_iu *) (iue->sbuf->buf);
}

static int send_iu(struct iu_entry *iue, uint64_t length, uint8_t format)
{
    struct srp_target *target = iue->target;
    struct vio_port *vport = target_to_port(target);
    long rc, rc1;
    union {
        struct viosrp_crq cooked;
        uint64_t raw[2];
    } crq;

    /* First copy the SRP */
    rc = h_copy_rdma(length, vport->liobn, iue->sbuf->dma,
             vport->riobn, iue->remote_token);

    if (rc)
        eprintk("Error %ld transferring data\n", rc);

    crq.cooked.valid = 0x80;
    crq.cooked.format = format;
    crq.cooked.reserved = 0x00;
    crq.cooked.timeout = 0x00;
    crq.cooked.IU_length = length;
    crq.cooked.IU_data_ptr = vio_iu(iue)->srp.rsp.tag;

    if (rc == 0)
        crq.cooked.status = 0x99;   /* Just needs to be non-zero */
    else
        crq.cooked.status = 0x00;

    rc1 = h_send_crq(vport->dma_dev->unit_address, crq.raw[0], crq.raw[1]);

    if (rc1) {
        eprintk("%ld sending response\n", rc1);
        return rc1;
    }

    return rc;
}

#define SRP_RSP_SENSE_DATA_LEN  18

static int send_rsp(struct iu_entry *iue, struct scsi_cmnd *sc,
            unsigned char status, unsigned char asc)
{
    union viosrp_iu *iu = vio_iu(iue);
    uint64_t tag = iu->srp.rsp.tag;

    /* If the linked bit is on and status is good */
    if (test_bit(V_LINKED, &iue->flags) && (status == NO_SENSE))
        status = 0x10;

    memset(iu, 0, sizeof(struct srp_rsp));
    iu->srp.rsp.opcode = SRP_RSP;
    iu->srp.rsp.req_lim_delta = 1;
    iu->srp.rsp.tag = tag;

    if (test_bit(V_DIOVER, &iue->flags))
        iu->srp.rsp.flags |= SRP_RSP_FLAG_DIOVER;

    iu->srp.rsp.data_in_res_cnt = 0;
    iu->srp.rsp.data_out_res_cnt = 0;

    iu->srp.rsp.flags &= ~SRP_RSP_FLAG_RSPVALID;

    iu->srp.rsp.resp_data_len = 0;
    iu->srp.rsp.status = status;
    if (status) {
        uint8_t *sense = iu->srp.rsp.data;

        if (sc) {
            iu->srp.rsp.flags |= SRP_RSP_FLAG_SNSVALID;
            iu->srp.rsp.sense_data_len = SCSI_SENSE_BUFFERSIZE;
            memcpy(sense, sc->sense_buffer, SCSI_SENSE_BUFFERSIZE);
        } else {
            iu->srp.rsp.status = SAM_STAT_CHECK_CONDITION;
            iu->srp.rsp.flags |= SRP_RSP_FLAG_SNSVALID;
            iu->srp.rsp.sense_data_len = SRP_RSP_SENSE_DATA_LEN;

            /* Valid bit and 'current errors' */
            sense[0] = (0x1 << 7 | 0x70);
            /* Sense key */
            sense[2] = status;
            /* Additional sense length */
            sense[7] = 0xa; /* 10 bytes */
            /* Additional sense code */
            sense[12] = asc;
        }
    }

    send_iu(iue, sizeof(iu->srp.rsp) + SRP_RSP_SENSE_DATA_LEN,
        VIOSRP_SRP_FORMAT);

    return 0;
}

static void handle_cmd_queue(struct srp_target *target)
{
    struct Scsi_Host *shost = target->shost;
    struct srp_rport *rport = target_to_port(target)->rport;
    struct iu_entry *iue;
    struct srp_cmd *cmd;
    unsigned long flags;
    int err;

retry:
    spin_lock_irqsave(&target->lock, flags);

    list_for_each_entry(iue, &target->cmd_queue, ilist) {
        if (!test_and_set_bit(V_FLYING, &iue->flags)) {
            spin_unlock_irqrestore(&target->lock, flags);
            cmd = iue->sbuf->buf;
            err = srp_cmd_queue(shost, cmd, iue,
                        (unsigned long)rport, 0);
            if (err) {
                eprintk("cannot queue cmd %p %d\n", cmd, err);
                srp_iu_put(iue);
            }
            goto retry;
        }
    }

    spin_unlock_irqrestore(&target->lock, flags);
}

static int ibmvstgt_rdma(struct scsi_cmnd *sc, struct scatterlist *sg, int nsg,
             struct srp_direct_buf *md, int nmd,
             enum dma_data_direction dir, unsigned int rest)
{
    struct iu_entry *iue = (struct iu_entry *) sc->SCp.ptr;
    struct srp_target *target = iue->target;
    struct vio_port *vport = target_to_port(target);
    dma_addr_t token;
    long err;
    unsigned int done = 0;
    int i, sidx, soff;

    sidx = soff = 0;
    token = sg_dma_address(sg + sidx);

    for (i = 0; i < nmd && rest; i++) {
        unsigned int mdone, mlen;

        mlen = min(rest, md[i].len);
        for (mdone = 0; mlen;) {
            int slen = min(sg_dma_len(sg + sidx) - soff, mlen);

            if (dir == DMA_TO_DEVICE)
                err = h_copy_rdma(slen,
                          vport->riobn,
                          md[i].va + mdone,
                          vport->liobn,
                          token + soff);
            else
                err = h_copy_rdma(slen,
                          vport->liobn,
                          token + soff,
                          vport->riobn,
                          md[i].va + mdone);

            if (err != H_SUCCESS) {
                eprintk("rdma error %d %d %ld\n", dir, slen, err);
                return -EIO;
            }

            mlen -= slen;
            mdone += slen;
            soff += slen;
            done += slen;

            if (soff == sg_dma_len(sg + sidx)) {
                sidx++;
                soff = 0;
                token = sg_dma_address(sg + sidx);

                if (sidx > nsg) {
                    eprintk("out of sg %p %d %d\n",
                        iue, sidx, nsg);
                    return -EIO;
                }
            }
        };

        rest -= mlen;
    }
    return 0;
}

static int ibmvstgt_cmd_done(struct scsi_cmnd *sc,
                 void (*done)(struct scsi_cmnd *))
{
    unsigned long flags;
    struct iu_entry *iue = (struct iu_entry *) sc->SCp.ptr;
    struct srp_target *target = iue->target;
    int err = 0;

    dprintk("%p %p %x %u\n", iue, target, vio_iu(iue)->srp.cmd.cdb[0],
        scsi_sg_count(sc));

    if (scsi_sg_count(sc))
        err = srp_transfer_data(sc, &vio_iu(iue)->srp.cmd, ibmvstgt_rdma, 1, 1);

    spin_lock_irqsave(&target->lock, flags);
    list_del(&iue->ilist);
    spin_unlock_irqrestore(&target->lock, flags);

    if (err|| sc->result != SAM_STAT_GOOD) {
        eprintk("operation failed %p %d %x\n",
            iue, sc->result, vio_iu(iue)->srp.cmd.cdb[0]);
        send_rsp(iue, sc, HARDWARE_ERROR, 0x00);
    } else
        send_rsp(iue, sc, NO_SENSE, 0x00);

    done(sc);
    srp_iu_put(iue);
    return 0;
}

int send_adapter_info(struct iu_entry *iue,
              dma_addr_t remote_buffer, uint16_t length)
{
    struct srp_target *target = iue->target;
    struct vio_port *vport = target_to_port(target);
    struct Scsi_Host *shost = target->shost;
    dma_addr_t data_token;
    struct mad_adapter_info_data *info;
    int err;

    info = dma_alloc_coherent(target->dev, sizeof(*info), &data_token,
                  GFP_KERNEL);
    if (!info) {
        eprintk("bad dma_alloc_coherent %p\n", target);
        return 1;
    }

    /* Get remote info */
    err = h_copy_rdma(sizeof(*info), vport->riobn, remote_buffer,
              vport->liobn, data_token);
    if (err == H_SUCCESS) {
        dprintk("Client connect: %s (%d)\n",
            info->partition_name, info->partition_number);
    }

    memset(info, 0, sizeof(*info));

    strcpy(info->srp_version, "16.a");
    strncpy(info->partition_name, partition_name,
        sizeof(info->partition_name));
    info->partition_number = partition_number;
    info->mad_version = 1;
    info->os_type = 2;
    info->port_max_txu[0] = shost->hostt->max_sectors << 9;

    /* Send our info to remote */
    err = h_copy_rdma(sizeof(*info), vport->liobn, data_token,
              vport->riobn, remote_buffer);

    dma_free_coherent(target->dev, sizeof(*info), info, data_token);

    if (err != H_SUCCESS) {
        eprintk("Error sending adapter info %d\n", err);
        return 1;
    }

    return 0;
}

static void process_login(struct iu_entry *iue)
{
    union viosrp_iu *iu = vio_iu(iue);
    struct srp_login_rsp *rsp = &iu->srp.login_rsp;
    uint64_t tag = iu->srp.rsp.tag;
    struct Scsi_Host *shost = iue->target->shost;
    struct srp_target *target = host_to_srp_target(shost);
    struct vio_port *vport = target_to_port(target);
    struct srp_rport_identifiers ids;

    memset(&ids, 0, sizeof(ids));
    sprintf(ids.port_id, "%x", vport->dma_dev->unit_address);
    ids.roles = SRP_RPORT_ROLE_INITIATOR;
    if (!vport->rport)
        vport->rport = srp_rport_add(shost, &ids);

    /* TODO handle case that requested size is wrong and
     * buffer format is wrong
     */
    memset(iu, 0, sizeof(struct srp_login_rsp));
    rsp->opcode = SRP_LOGIN_RSP;
    rsp->req_lim_delta = INITIAL_SRP_LIMIT;
    rsp->tag = tag;
    rsp->max_it_iu_len = sizeof(union srp_iu);
    rsp->max_ti_iu_len = sizeof(union srp_iu);
    /* direct and indirect */
    rsp->buf_fmt = SRP_BUF_FORMAT_DIRECT | SRP_BUF_FORMAT_INDIRECT;

    send_iu(iue, sizeof(*rsp), VIOSRP_SRP_FORMAT);
}

static inline void queue_cmd(struct iu_entry *iue)
{
    struct srp_target *target = iue->target;
    unsigned long flags;

    spin_lock_irqsave(&target->lock, flags);
    list_add_tail(&iue->ilist, &target->cmd_queue);
    spin_unlock_irqrestore(&target->lock, flags);
}

static int process_tsk_mgmt(struct iu_entry *iue)
{
    union viosrp_iu *iu = vio_iu(iue);
    int fn;

    dprintk("%p %u\n", iue, iu->srp.tsk_mgmt.tsk_mgmt_func);

    switch (iu->srp.tsk_mgmt.tsk_mgmt_func) {
    case SRP_TSK_ABORT_TASK:
        fn = ABORT_TASK;
        break;
    case SRP_TSK_ABORT_TASK_SET:
        fn = ABORT_TASK_SET;
        break;
    case SRP_TSK_CLEAR_TASK_SET:
        fn = CLEAR_TASK_SET;
        break;
    case SRP_TSK_LUN_RESET:
        fn = LOGICAL_UNIT_RESET;
        break;
    case SRP_TSK_CLEAR_ACA:
        fn = CLEAR_ACA;
        break;
    default:
        fn = 0;
    }
    if (fn)
        scsi_tgt_tsk_mgmt_request(iue->target->shost,
                      (unsigned long)iue->target->shost,
                      fn,
                      iu->srp.tsk_mgmt.task_tag,
                      (struct scsi_lun *) &iu->srp.tsk_mgmt.lun,
                      iue);
    else
        send_rsp(iue, NULL, ILLEGAL_REQUEST, 0x20);

    return !fn;
}

static int process_mad_iu(struct iu_entry *iue)
{
    union viosrp_iu *iu = vio_iu(iue);
    struct viosrp_adapter_info *info;
    struct viosrp_host_config *conf;

    switch (iu->mad.empty_iu.common.type) {
    case VIOSRP_EMPTY_IU_TYPE:
        eprintk("%s\n", "Unsupported EMPTY MAD IU");
        break;
    case VIOSRP_ERROR_LOG_TYPE:
        eprintk("%s\n", "Unsupported ERROR LOG MAD IU");
        iu->mad.error_log.common.status = 1;
        send_iu(iue, sizeof(iu->mad.error_log), VIOSRP_MAD_FORMAT);
        break;
    case VIOSRP_ADAPTER_INFO_TYPE:
        info = &iu->mad.adapter_info;
        info->common.status = send_adapter_info(iue, info->buffer,
                            info->common.length);
        send_iu(iue, sizeof(*info), VIOSRP_MAD_FORMAT);
        break;
    case VIOSRP_HOST_CONFIG_TYPE:
        conf = &iu->mad.host_config;
        conf->common.status = 1;
        send_iu(iue, sizeof(*conf), VIOSRP_MAD_FORMAT);
        break;
    default:
        eprintk("Unknown type %u\n", iu->srp.rsp.opcode);
    }

    return 1;
}

static int process_srp_iu(struct iu_entry *iue)
{
    union viosrp_iu *iu = vio_iu(iue);
    int done = 1;
    u8 opcode = iu->srp.rsp.opcode;

    switch (opcode) {
    case SRP_LOGIN_REQ:
        process_login(iue);
        break;
    case SRP_TSK_MGMT:
        done = process_tsk_mgmt(iue);
        break;
    case SRP_CMD:
        queue_cmd(iue);
        done = 0;
        break;
    case SRP_LOGIN_RSP:
    case SRP_I_LOGOUT:
    case SRP_T_LOGOUT:
    case SRP_RSP:
    case SRP_CRED_REQ:
    case SRP_CRED_RSP:
    case SRP_AER_REQ:
    case SRP_AER_RSP:
        eprintk("Unsupported type %u\n", opcode);
        break;
    default:
        eprintk("Unknown type %u\n", opcode);
    }

    return done;
}

static void process_iu(struct viosrp_crq *crq, struct srp_target *target)
{
    struct vio_port *vport = target_to_port(target);
    struct iu_entry *iue;
    long err;
    int done = 1;

    iue = srp_iu_get(target);
    if (!iue) {
        eprintk("Error getting IU from pool, %p\n", target);
        return;
    }

    iue->remote_token = crq->IU_data_ptr;

    err = h_copy_rdma(crq->IU_length, vport->riobn,
              iue->remote_token, vport->liobn, iue->sbuf->dma);

    if (err != H_SUCCESS) {
        eprintk("%ld transferring data error %p\n", err, iue);
        goto out;
    }

    if (crq->format == VIOSRP_MAD_FORMAT)
        done = process_mad_iu(iue);
    else
        done = process_srp_iu(iue);
out:
    if (done)
        srp_iu_put(iue);
}

static irqreturn_t ibmvstgt_interrupt(int dummy, void *data)
{
    struct srp_target *target = data;
    struct vio_port *vport = target_to_port(target);

    vio_disable_interrupts(vport->dma_dev);
    queue_work(vtgtd, &vport->crq_work);

    return IRQ_HANDLED;
}

static int crq_queue_create(struct crq_queue *queue, struct srp_target *target)
{
    int err;
    struct vio_port *vport = target_to_port(target);

    queue->msgs = (struct viosrp_crq *) get_zeroed_page(GFP_KERNEL);
    if (!queue->msgs)
        goto malloc_failed;
    queue->size = PAGE_SIZE / sizeof(*queue->msgs);

    queue->msg_token = dma_map_single(target->dev, queue->msgs,
                      queue->size * sizeof(*queue->msgs),
                      DMA_BIDIRECTIONAL);

    if (dma_mapping_error(target->dev, queue->msg_token))
        goto map_failed;

    err = h_reg_crq(vport->dma_dev->unit_address, queue->msg_token,
            PAGE_SIZE);

    /* If the adapter was left active for some reason (like kexec)
     * try freeing and re-registering
     */
    if (err == H_RESOURCE) {
        do {
        err = h_free_crq(vport->dma_dev->unit_address);
        } while (err == H_BUSY || H_IS_LONG_BUSY(err));

        err = h_reg_crq(vport->dma_dev->unit_address, queue->msg_token,
                PAGE_SIZE);
    }

    if (err != H_SUCCESS && err != 2) {
        eprintk("Error 0x%x opening virtual adapter\n", err);
        goto reg_crq_failed;
    }

    err = request_irq(vport->dma_dev->irq, &ibmvstgt_interrupt,
              IRQF_DISABLED, "ibmvstgt", target);
    if (err)
        goto req_irq_failed;

    vio_enable_interrupts(vport->dma_dev);

    h_send_crq(vport->dma_dev->unit_address, 0xC001000000000000, 0);

    queue->cur = 0;
    spin_lock_init(&queue->lock);

    return 0;

req_irq_failed:
    do {
        err = h_free_crq(vport->dma_dev->unit_address);
    } while (err == H_BUSY || H_IS_LONG_BUSY(err));

reg_crq_failed:
    dma_unmap_single(target->dev, queue->msg_token,
             queue->size * sizeof(*queue->msgs), DMA_BIDIRECTIONAL);
map_failed:
    free_page((unsigned long) queue->msgs);

malloc_failed:
    return -ENOMEM;
}

static void crq_queue_destroy(struct srp_target *target)
{
    struct vio_port *vport = target_to_port(target);
    struct crq_queue *queue = &vport->crq_queue;
    int err;

    free_irq(vport->dma_dev->irq, target);
    do {
        err = h_free_crq(vport->dma_dev->unit_address);
    } while (err == H_BUSY || H_IS_LONG_BUSY(err));

    dma_unmap_single(target->dev, queue->msg_token,
             queue->size * sizeof(*queue->msgs), DMA_BIDIRECTIONAL);

    free_page((unsigned long) queue->msgs);
}

static void process_crq(struct viosrp_crq *crq, struct srp_target *target)
{
    struct vio_port *vport = target_to_port(target);
    dprintk("%x %x\n", crq->valid, crq->format);

    switch (crq->valid) {
    case 0xC0:
        /* initialization */
        switch (crq->format) {
        case 0x01:
            h_send_crq(vport->dma_dev->unit_address,
                   0xC002000000000000, 0);
            break;
        case 0x02:
            break;
        default:
            eprintk("Unknown format %u\n", crq->format);
        }
        break;
    case 0xFF:
        /* transport event */
        break;
    case 0x80:
        /* real payload */
        switch (crq->format) {
        case VIOSRP_SRP_FORMAT:
        case VIOSRP_MAD_FORMAT:
            process_iu(crq, target);
            break;
        case VIOSRP_OS400_FORMAT:
        case VIOSRP_AIX_FORMAT:
        case VIOSRP_LINUX_FORMAT:
        case VIOSRP_INLINE_FORMAT:
            eprintk("Unsupported format %u\n", crq->format);
            break;
        default:
            eprintk("Unknown format %u\n", crq->format);
        }
        break;
    default:
        eprintk("unknown message type 0x%02x!?\n", crq->valid);
    }
}

static inline struct viosrp_crq *next_crq(struct crq_queue *queue)
{
    struct viosrp_crq *crq;
    unsigned long flags;

    spin_lock_irqsave(&queue->lock, flags);
    crq = &queue->msgs[queue->cur];
    if (crq->valid & 0x80) {
        if (++queue->cur == queue->size)
            queue->cur = 0;
    } else
        crq = NULL;
    spin_unlock_irqrestore(&queue->lock, flags);

    return crq;
}

static void handle_crq(struct work_struct *work)
{
    struct vio_port *vport = container_of(work, struct vio_port, crq_work);
    struct srp_target *target = vport->target;
    struct viosrp_crq *crq;
    int done = 0;

    while (!done) {
        while ((crq = next_crq(&vport->crq_queue)) != NULL) {
            process_crq(crq, target);
            crq->valid = 0x00;
        }

        vio_enable_interrupts(vport->dma_dev);

        crq = next_crq(&vport->crq_queue);
        if (crq) {
            vio_disable_interrupts(vport->dma_dev);
            process_crq(crq, target);
            crq->valid = 0x00;
        } else
            done = 1;
    }

    handle_cmd_queue(target);
}


static int ibmvstgt_eh_abort_handler(struct scsi_cmnd *sc)
{
    unsigned long flags;
    struct iu_entry *iue = (struct iu_entry *) sc->SCp.ptr;
    struct srp_target *target = iue->target;

    dprintk("%p %p %x\n", iue, target, vio_iu(iue)->srp.cmd.cdb[0]);

    spin_lock_irqsave(&target->lock, flags);
    list_del(&iue->ilist);
    spin_unlock_irqrestore(&target->lock, flags);

    srp_iu_put(iue);

    return 0;
}

static int ibmvstgt_tsk_mgmt_response(struct Scsi_Host *shost,
                      u64 itn_id, u64 mid, int result)
{
    struct iu_entry *iue = (struct iu_entry *) ((void *) mid);
    union viosrp_iu *iu = vio_iu(iue);
    unsigned char status, asc;

    eprintk("%p %d\n", iue, result);
    status = NO_SENSE;
    asc = 0;

    switch (iu->srp.tsk_mgmt.tsk_mgmt_func) {
    case SRP_TSK_ABORT_TASK:
        asc = 0x14;
        if (result)
            status = ABORTED_COMMAND;
        break;
    default:
        break;
    }

    send_rsp(iue, NULL, status, asc);
    srp_iu_put(iue);

    return 0;
}

static int ibmvstgt_it_nexus_response(struct Scsi_Host *shost, u64 itn_id,
                      int result)
{
    struct srp_target *target = host_to_srp_target(shost);
    struct vio_port *vport = target_to_port(target);

    if (result) {
        eprintk("%p %d\n", shost, result);
        srp_rport_del(vport->rport);
        vport->rport = NULL;
    }
    return 0;
}

static ssize_t system_id_show(struct device *dev,
                  struct device_attribute *attr, char *buf)
{
    return snprintf(buf, PAGE_SIZE, "%s\n", system_id);
}

static ssize_t partition_number_show(struct device *dev,
                     struct device_attribute *attr, char *buf)
{
    return snprintf(buf, PAGE_SIZE, "%x\n", partition_number);
}

static ssize_t unit_address_show(struct device *dev,
                  struct device_attribute *attr, char *buf)
{
    struct Scsi_Host *shost = class_to_shost(dev);
    struct srp_target *target = host_to_srp_target(shost);
    struct vio_port *vport = target_to_port(target);
    return snprintf(buf, PAGE_SIZE, "%x\n", vport->dma_dev->unit_address);
}

static DEVICE_ATTR(system_id, S_IRUGO, system_id_show, NULL);
static DEVICE_ATTR(partition_number, S_IRUGO, partition_number_show, NULL);
static DEVICE_ATTR(unit_address, S_IRUGO, unit_address_show, NULL);

static struct device_attribute *ibmvstgt_attrs[] = {
    &dev_attr_system_id,
    &dev_attr_partition_number,
    &dev_attr_unit_address,
    NULL,
};

static struct scsi_host_template ibmvstgt_sht = {
    .name           = TGT_NAME,
    .module         = THIS_MODULE,
    .can_queue      = INITIAL_SRP_LIMIT,
    .sg_tablesize       = SG_ALL,
    .use_clustering     = DISABLE_CLUSTERING,
    .max_sectors        = DEFAULT_MAX_SECTORS,
    .transfer_response  = ibmvstgt_cmd_done,
    .eh_abort_handler   = ibmvstgt_eh_abort_handler,
    .shost_attrs        = ibmvstgt_attrs,
    .proc_name      = TGT_NAME,
    .supported_mode     = MODE_TARGET,
};

static int ibmvstgt_probe(struct vio_dev *dev, const struct vio_device_id *id)
{
    struct Scsi_Host *shost;
    struct srp_target *target;
    struct vio_port *vport;
    unsigned int *dma, dma_size;
    int err = -ENOMEM;

    vport = kzalloc(sizeof(struct vio_port), GFP_KERNEL);
    if (!vport)
        return err;
    shost = scsi_host_alloc(&ibmvstgt_sht, sizeof(struct srp_target));
    if (!shost)
        goto free_vport;
    shost->transportt = ibmvstgt_transport_template;

    target = host_to_srp_target(shost);
    target->shost = shost;
    vport->dma_dev = dev;
    target->ldata = vport;
    vport->target = target;
    err = srp_target_alloc(target, &dev->dev, INITIAL_SRP_LIMIT,
                   SRP_MAX_IU_LEN);
    if (err)
        goto put_host;

    dma = (unsigned int *) vio_get_attribute(dev, "ibm,my-dma-window",
                         &dma_size);
    if (!dma || dma_size != 40) {
        eprintk("Couldn't get window property %d\n", dma_size);
        err = -EIO;
        goto free_srp_target;
    }
    vport->liobn = dma[0];
    vport->riobn = dma[5];

    INIT_WORK(&vport->crq_work, handle_crq);

    err = scsi_add_host(shost, target->dev);
    if (err)
        goto free_srp_target;

    err = scsi_tgt_alloc_queue(shost);
    if (err)
        goto remove_host;

    err = crq_queue_create(&vport->crq_queue, target);
    if (err)
        goto free_queue;

    return 0;
free_queue:
    scsi_tgt_free_queue(shost);
remove_host:
    scsi_remove_host(shost);
free_srp_target:
    srp_target_free(target);
put_host:
    scsi_host_put(shost);
free_vport:
    kfree(vport);
    return err;
}

static int ibmvstgt_remove(struct vio_dev *dev)
{
    struct srp_target *target = dev_get_drvdata(&dev->dev);
    struct Scsi_Host *shost = target->shost;
    struct vio_port *vport = target->ldata;

    crq_queue_destroy(target);
    srp_remove_host(shost);
    scsi_remove_host(shost);
    scsi_tgt_free_queue(shost);
    srp_target_free(target);
    kfree(vport);
    scsi_host_put(shost);
    return 0;
}

static struct vio_device_id ibmvstgt_device_table[] __devinitdata = {
    {"v-scsi-host", "IBM,v-scsi-host"},
    {"",""}
};

MODULE_DEVICE_TABLE(vio, ibmvstgt_device_table);

static struct vio_driver ibmvstgt_driver = {
    .id_table = ibmvstgt_device_table,
    .probe = ibmvstgt_probe,
    .remove = ibmvstgt_remove,
    .name = "ibmvscsis",
};

static int get_system_info(void)
{
    struct device_node *rootdn;
    const char *id, *model, *name;
    const unsigned int *num;

    rootdn = of_find_node_by_path("/");
    if (!rootdn)
        return -ENOENT;

    model = of_get_property(rootdn, "model", NULL);
    id = of_get_property(rootdn, "system-id", NULL);
    if (model && id)
        snprintf(system_id, sizeof(system_id), "%s-%s", model, id);

    name = of_get_property(rootdn, "ibm,partition-name", NULL);
    if (name)
        strncpy(partition_name, name, sizeof(partition_name));

    num = of_get_property(rootdn, "ibm,partition-no", NULL);
    if (num)
        partition_number = *num;

    of_node_put(rootdn);
    return 0;
}

static struct srp_function_template ibmvstgt_transport_functions = {
    .tsk_mgmt_response = ibmvstgt_tsk_mgmt_response,
    .it_nexus_response = ibmvstgt_it_nexus_response,
};

static int __init ibmvstgt_init(void)
{
    int err = -ENOMEM;

    printk("IBM eServer i/pSeries Virtual SCSI Target Driver\n");

    ibmvstgt_transport_template =
        srp_attach_transport(&ibmvstgt_transport_functions);
    if (!ibmvstgt_transport_template)
        return err;

    vtgtd = create_workqueue("ibmvtgtd");
    if (!vtgtd)
        goto release_transport;

    err = get_system_info();
    if (err)
        goto destroy_wq;

    err = vio_register_driver(&ibmvstgt_driver);
    if (err)
        goto destroy_wq;

    return 0;
destroy_wq:
    destroy_workqueue(vtgtd);
release_transport:
    srp_release_transport(ibmvstgt_transport_template);
    return err;
}

static void __exit ibmvstgt_exit(void)
{
    printk("Unregister IBM virtual SCSI driver\n");

    destroy_workqueue(vtgtd);
    vio_unregister_driver(&ibmvstgt_driver);
    srp_release_transport(ibmvstgt_transport_template);
}

MODULE_DESCRIPTION("IBM Virtual SCSI Target");
MODULE_AUTHOR("Santiago Leon");
MODULE_LICENSE("GPL");

module_init(ibmvstgt_init);
module_exit(ibmvstgt_exit);