tape_34xx.c

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/*
 *    tape device discipline for 3480/3490 tapes.
 *
 *    Copyright IBM Corp. 2001, 2009
 *    Author(s): Carsten Otte <[email protected]>
 *       Tuan Ngo-Anh <[email protected]>
 *       Martin Schwidefsky <[email protected]>
 */

#define KMSG_COMPONENT "tape_34xx"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

#include <linux/module.h>
#include <linux/init.h>
#include <linux/bio.h>
#include <linux/workqueue.h>
#include <linux/slab.h>

#define TAPE_DBF_AREA   tape_34xx_dbf

#include "tape.h"
#include "tape_std.h"

/*
 * Pointer to debug area.
 */
debug_info_t *TAPE_DBF_AREA = NULL;
EXPORT_SYMBOL(TAPE_DBF_AREA);

#define TAPE34XX_FMT_3480   0
#define TAPE34XX_FMT_3480_2_XF  1
#define TAPE34XX_FMT_3480_XF    2

struct tape_34xx_block_id {
    unsigned int    wrap        : 1;
    unsigned int    segment     : 7;
    unsigned int    format      : 2;
    unsigned int    block       : 22;
};

/*
 * A list of block ID's is used to faster seek blocks.
 */
struct tape_34xx_sbid {
    struct list_head        list;
    struct tape_34xx_block_id   bid;
};

static void tape_34xx_delete_sbid_from(struct tape_device *, int);

/*
 * Medium sense for 34xx tapes. There is no 'real' medium sense call.
 * So we just do a normal sense.
 */
static void __tape_34xx_medium_sense(struct tape_request *request)
{
    struct tape_device *device = request->device;
    unsigned char *sense;

    if (request->rc == 0) {
        sense = request->cpdata;

        /*
         * This isn't quite correct. But since INTERVENTION_REQUIRED
         * means that the drive is 'neither ready nor on-line' it is
         * only slightly inaccurate to say there is no tape loaded if
         * the drive isn't online...
         */
        if (sense[0] & SENSE_INTERVENTION_REQUIRED)
            tape_med_state_set(device, MS_UNLOADED);
        else
            tape_med_state_set(device, MS_LOADED);

        if (sense[1] & SENSE_WRITE_PROTECT)
            device->tape_generic_status |= GMT_WR_PROT(~0);
        else
            device->tape_generic_status &= ~GMT_WR_PROT(~0);
    } else
        DBF_EVENT(4, "tape_34xx: medium sense failed with rc=%d\n",
            request->rc);
    tape_free_request(request);
}

static int tape_34xx_medium_sense(struct tape_device *device)
{
    struct tape_request *request;
    int rc;

    request = tape_alloc_request(1, 32);
    if (IS_ERR(request)) {
        DBF_EXCEPTION(6, "MSEN fail\n");
        return PTR_ERR(request);
    }

    request->op = TO_MSEN;
    tape_ccw_end(request->cpaddr, SENSE, 32, request->cpdata);
    rc = tape_do_io_interruptible(device, request);
    __tape_34xx_medium_sense(request);
    return rc;
}

static void tape_34xx_medium_sense_async(struct tape_device *device)
{
    struct tape_request *request;

    request = tape_alloc_request(1, 32);
    if (IS_ERR(request)) {
        DBF_EXCEPTION(6, "MSEN fail\n");
        return;
    }

    request->op = TO_MSEN;
    tape_ccw_end(request->cpaddr, SENSE, 32, request->cpdata);
    request->callback = (void *) __tape_34xx_medium_sense;
    request->callback_data = NULL;
    tape_do_io_async(device, request);
}

struct tape_34xx_work {
    struct tape_device  *device;
    enum tape_op         op;
    struct work_struct   work;
};

/*
 * These functions are currently used only to schedule a medium_sense for
 * later execution. This is because we get an interrupt whenever a medium
 * is inserted but cannot call tape_do_io* from an interrupt context.
 * Maybe that's useful for other actions we want to start from the
 * interrupt handler.
 * Note: the work handler is called by the system work queue. The tape
 * commands started by the handler need to be asynchrounous, otherwise
 * a deadlock can occur e.g. in case of a deferred cc=1 (see __tape_do_irq).
 */
static void
tape_34xx_work_handler(struct work_struct *work)
{
    struct tape_34xx_work *p =
        container_of(work, struct tape_34xx_work, work);
    struct tape_device *device = p->device;

    switch(p->op) {
        case TO_MSEN:
            tape_34xx_medium_sense_async(device);
            break;
        default:
            DBF_EVENT(3, "T34XX: internal error: unknown work\n");
    }
    tape_put_device(device);
    kfree(p);
}

static int
tape_34xx_schedule_work(struct tape_device *device, enum tape_op op)
{
    struct tape_34xx_work *p;

    if ((p = kzalloc(sizeof(*p), GFP_ATOMIC)) == NULL)
        return -ENOMEM;

    INIT_WORK(&p->work, tape_34xx_work_handler);

    p->device = tape_get_device(device);
    p->op     = op;

    schedule_work(&p->work);
    return 0;
}

/*
 * Done Handler is called when dev stat = DEVICE-END (successful operation)
 */
static inline int
tape_34xx_done(struct tape_request *request)
{
    DBF_EVENT(6, "%s done\n", tape_op_verbose[request->op]);

    switch (request->op) {
        case TO_DSE:
        case TO_RUN:
        case TO_WRI:
        case TO_WTM:
        case TO_ASSIGN:
        case TO_UNASSIGN:
            tape_34xx_delete_sbid_from(request->device, 0);
            break;
        default:
            ;
    }
    return TAPE_IO_SUCCESS;
}

static inline int
tape_34xx_erp_failed(struct tape_request *request, int rc)
{
    DBF_EVENT(3, "Error recovery failed for %s (RC=%d)\n",
          tape_op_verbose[request->op], rc);
    return rc;
}

static inline int
tape_34xx_erp_succeeded(struct tape_request *request)
{
    DBF_EVENT(3, "Error Recovery successful for %s\n",
          tape_op_verbose[request->op]);
    return tape_34xx_done(request);
}

static inline int
tape_34xx_erp_retry(struct tape_request *request)
{
    DBF_EVENT(3, "xerp retr %s\n", tape_op_verbose[request->op]);
    return TAPE_IO_RETRY;
}

/*
 * This function is called, when no request is outstanding and we get an
 * interrupt
 */
static int
tape_34xx_unsolicited_irq(struct tape_device *device, struct irb *irb)
{
    if (irb->scsw.cmd.dstat == 0x85) { /* READY */
        /* A medium was inserted in the drive. */
        DBF_EVENT(6, "xuud med\n");
        tape_34xx_delete_sbid_from(device, 0);
        tape_34xx_schedule_work(device, TO_MSEN);
    } else {
        DBF_EVENT(3, "unsol.irq! dev end: %08x\n", device->cdev_id);
        tape_dump_sense_dbf(device, NULL, irb);
    }
    return TAPE_IO_SUCCESS;
}

/*
 * Read Opposite Error Recovery Function:
 * Used, when Read Forward does not work
 */
static int
tape_34xx_erp_read_opposite(struct tape_device *device,
                struct tape_request *request)
{
    if (request->op == TO_RFO) {
        /*
         * We did read forward, but the data could not be read
         * *correctly*. We transform the request to a read backward
         * and try again.
         */
        tape_std_read_backward(device, request);
        return tape_34xx_erp_retry(request);
    }

    /*
     * We tried to read forward and backward, but hat no
     * success -> failed.
     */
    return tape_34xx_erp_failed(request, -EIO);
}

static int
tape_34xx_erp_bug(struct tape_device *device, struct tape_request *request,
          struct irb *irb, int no)
{
    if (request->op != TO_ASSIGN) {
        dev_err(&device->cdev->dev, "An unexpected condition %d "
            "occurred in tape error recovery\n", no);
        tape_dump_sense_dbf(device, request, irb);
    }
    return tape_34xx_erp_failed(request, -EIO);
}

/*
 * Handle data overrun between cu and drive. The channel speed might
 * be too slow.
 */
static int
tape_34xx_erp_overrun(struct tape_device *device, struct tape_request *request,
              struct irb *irb)
{
    if (irb->ecw[3] == 0x40) {
        dev_warn (&device->cdev->dev, "A data overrun occurred between"
            " the control unit and tape unit\n");
        return tape_34xx_erp_failed(request, -EIO);
    }
    return tape_34xx_erp_bug(device, request, irb, -1);
}

/*
 * Handle record sequence error.
 */
static int
tape_34xx_erp_sequence(struct tape_device *device,
               struct tape_request *request, struct irb *irb)
{
    if (irb->ecw[3] == 0x41) {
        /*
         * cu detected incorrect block-id sequence on tape.
         */
        dev_warn (&device->cdev->dev, "The block ID sequence on the "
            "tape is incorrect\n");
        return tape_34xx_erp_failed(request, -EIO);
    }
    /*
     * Record sequence error bit is set, but erpa does not
     * show record sequence error.
     */
    return tape_34xx_erp_bug(device, request, irb, -2);
}

/*
 * This function analyses the tape's sense-data in case of a unit-check.
 * If possible, it tries to recover from the error. Else the user is
 * informed about the problem.
 */
static int
tape_34xx_unit_check(struct tape_device *device, struct tape_request *request,
             struct irb *irb)
{
    int inhibit_cu_recovery;
    __u8* sense;

    inhibit_cu_recovery = (*device->modeset_byte & 0x80) ? 1 : 0;
    sense = irb->ecw;

    if (
        sense[0] & SENSE_COMMAND_REJECT &&
        sense[1] & SENSE_WRITE_PROTECT
    ) {
        if (
            request->op == TO_DSE ||
            request->op == TO_WRI ||
            request->op == TO_WTM
        ) {
            /* medium is write protected */
            return tape_34xx_erp_failed(request, -EACCES);
        } else {
            return tape_34xx_erp_bug(device, request, irb, -3);
        }
    }

    /*
     * Special cases for various tape-states when reaching
     * end of recorded area
     *
     * FIXME: Maybe a special case of the special case:
     *        sense[0] == SENSE_EQUIPMENT_CHECK &&
     *        sense[1] == SENSE_DRIVE_ONLINE    &&
     *        sense[3] == 0x47 (Volume Fenced)
     *
     *        This was caused by continued FSF or FSR after an
     *        'End Of Data'.
     */
    if ((
        sense[0] == SENSE_DATA_CHECK      ||
        sense[0] == SENSE_EQUIPMENT_CHECK ||
        sense[0] == SENSE_EQUIPMENT_CHECK + SENSE_DEFERRED_UNIT_CHECK
    ) && (
        sense[1] == SENSE_DRIVE_ONLINE ||
        sense[1] == SENSE_BEGINNING_OF_TAPE + SENSE_WRITE_MODE
    )) {
        switch (request->op) {
        /*
         * sense[0] == SENSE_DATA_CHECK   &&
         * sense[1] == SENSE_DRIVE_ONLINE
         * sense[3] == 0x36 (End Of Data)
         *
         * Further seeks might return a 'Volume Fenced'.
         */
        case TO_FSF:
        case TO_FSB:
            /* Trying to seek beyond end of recorded area */
            return tape_34xx_erp_failed(request, -ENOSPC);
        case TO_BSB:
            return tape_34xx_erp_retry(request);

        /*
         * sense[0] == SENSE_DATA_CHECK   &&
         * sense[1] == SENSE_DRIVE_ONLINE &&
         * sense[3] == 0x36 (End Of Data)
         */
        case TO_LBL:
            /* Block could not be located. */
            tape_34xx_delete_sbid_from(device, 0);
            return tape_34xx_erp_failed(request, -EIO);

        case TO_RFO:
            /* Read beyond end of recorded area -> 0 bytes read */
            return tape_34xx_erp_failed(request, 0);

        /*
         * sense[0] == SENSE_EQUIPMENT_CHECK &&
         * sense[1] == SENSE_DRIVE_ONLINE    &&
         * sense[3] == 0x38 (Physical End Of Volume)
         */
        case TO_WRI:
            /* Writing at physical end of volume */
            return tape_34xx_erp_failed(request, -ENOSPC);
        default:
            return tape_34xx_erp_failed(request, 0);
        }
    }

    /* Sensing special bits */
    if (sense[0] & SENSE_BUS_OUT_CHECK)
        return tape_34xx_erp_retry(request);

    if (sense[0] & SENSE_DATA_CHECK) {
        /*
         * hardware failure, damaged tape or improper
         * operating conditions
         */
        switch (sense[3]) {
        case 0x23:
            /* a read data check occurred */
            if ((sense[2] & SENSE_TAPE_SYNC_MODE) ||
                inhibit_cu_recovery)
                // data check is not permanent, may be
                // recovered. We always use async-mode with
                // cu-recovery, so this should *never* happen.
                return tape_34xx_erp_bug(device, request,
                             irb, -4);

            /* data check is permanent, CU recovery has failed */
            dev_warn (&device->cdev->dev, "A read error occurred "
                "that cannot be recovered\n");
            return tape_34xx_erp_failed(request, -EIO);
        case 0x25:
            // a write data check occurred
            if ((sense[2] & SENSE_TAPE_SYNC_MODE) ||
                inhibit_cu_recovery)
                // data check is not permanent, may be
                // recovered. We always use async-mode with
                // cu-recovery, so this should *never* happen.
                return tape_34xx_erp_bug(device, request,
                             irb, -5);

            // data check is permanent, cu-recovery has failed
            dev_warn (&device->cdev->dev, "A write error on the "
                "tape cannot be recovered\n");
            return tape_34xx_erp_failed(request, -EIO);
        case 0x26:
            /* Data Check (read opposite) occurred. */
            return tape_34xx_erp_read_opposite(device, request);
        case 0x28:
            /* ID-Mark at tape start couldn't be written */
            dev_warn (&device->cdev->dev, "Writing the ID-mark "
                "failed\n");
            return tape_34xx_erp_failed(request, -EIO);
        case 0x31:
            /* Tape void. Tried to read beyond end of device. */
            dev_warn (&device->cdev->dev, "Reading the tape beyond"
                " the end of the recorded area failed\n");
            return tape_34xx_erp_failed(request, -ENOSPC);
        case 0x41:
            /* Record sequence error. */
            dev_warn (&device->cdev->dev, "The tape contains an "
                "incorrect block ID sequence\n");
            return tape_34xx_erp_failed(request, -EIO);
        default:
            /* all data checks for 3480 should result in one of
             * the above erpa-codes. For 3490, other data-check
             * conditions do exist. */
            if (device->cdev->id.driver_info == tape_3480)
                return tape_34xx_erp_bug(device, request,
                             irb, -6);
        }
    }

    if (sense[0] & SENSE_OVERRUN)
        return tape_34xx_erp_overrun(device, request, irb);

    if (sense[1] & SENSE_RECORD_SEQUENCE_ERR)
        return tape_34xx_erp_sequence(device, request, irb);

    /* Sensing erpa codes */
    switch (sense[3]) {
    case 0x00:
        /* Unit check with erpa code 0. Report and ignore. */
        return TAPE_IO_SUCCESS;
    case 0x21:
        /*
         * Data streaming not operational. CU will switch to
         * interlock mode. Reissue the command.
         */
        return tape_34xx_erp_retry(request);
    case 0x22:
        /*
         * Path equipment check. Might be drive adapter error, buffer
         * error on the lower interface, internal path not usable,
         * or error during cartridge load.
         */
        dev_warn (&device->cdev->dev, "A path equipment check occurred"
            " for the tape device\n");
        return tape_34xx_erp_failed(request, -EIO);
    case 0x24:
        /*
         * Load display check. Load display was command was issued,
         * but the drive is displaying a drive check message. Can
         * be threated as "device end".
         */
        return tape_34xx_erp_succeeded(request);
    case 0x27:
        /*
         * Command reject. May indicate illegal channel program or
         * buffer over/underrun. Since all channel programs are
         * issued by this driver and ought be correct, we assume a
         * over/underrun situation and retry the channel program.
         */
        return tape_34xx_erp_retry(request);
    case 0x29:
        /*
         * Function incompatible. Either the tape is idrc compressed
         * but the hardware isn't capable to do idrc, or a perform
         * subsystem func is issued and the CU is not on-line.
         */
        return tape_34xx_erp_failed(request, -EIO);
    case 0x2a:
        /*
         * Unsolicited environmental data. An internal counter
         * overflows, we can ignore this and reissue the cmd.
         */
        return tape_34xx_erp_retry(request);
    case 0x2b:
        /*
         * Environmental data present. Indicates either unload
         * completed ok or read buffered log command completed ok.
         */
        if (request->op == TO_RUN) {
            /* Rewind unload completed ok. */
            tape_med_state_set(device, MS_UNLOADED);
            return tape_34xx_erp_succeeded(request);
        }
        /* tape_34xx doesn't use read buffered log commands. */
        return tape_34xx_erp_bug(device, request, irb, sense[3]);
    case 0x2c:
        /*
         * Permanent equipment check. CU has tried recovery, but
         * did not succeed.
         */
        return tape_34xx_erp_failed(request, -EIO);
    case 0x2d:
        /* Data security erase failure. */
        if (request->op == TO_DSE)
            return tape_34xx_erp_failed(request, -EIO);
        /* Data security erase failure, but no such command issued. */
        return tape_34xx_erp_bug(device, request, irb, sense[3]);
    case 0x2e:
        /*
         * Not capable. This indicates either that the drive fails
         * reading the format id mark or that that format specified
         * is not supported by the drive.
         */
        dev_warn (&device->cdev->dev, "The tape unit cannot process "
            "the tape format\n");
        return tape_34xx_erp_failed(request, -EMEDIUMTYPE);
    case 0x30:
        /* The medium is write protected. */
        dev_warn (&device->cdev->dev, "The tape medium is write-"
            "protected\n");
        return tape_34xx_erp_failed(request, -EACCES);
    case 0x32:
        // Tension loss. We cannot recover this, it's an I/O error.
        dev_warn (&device->cdev->dev, "The tape does not have the "
            "required tape tension\n");
        return tape_34xx_erp_failed(request, -EIO);
    case 0x33:
        /*
         * Load Failure. The cartridge was not inserted correctly or
         * the tape is not threaded correctly.
         */
        dev_warn (&device->cdev->dev, "The tape unit failed to load"
            " the cartridge\n");
        tape_34xx_delete_sbid_from(device, 0);
        return tape_34xx_erp_failed(request, -EIO);
    case 0x34:
        /*
         * Unload failure. The drive cannot maintain tape tension
         * and control tape movement during an unload operation.
         */
        dev_warn (&device->cdev->dev, "Automatic unloading of the tape"
            " cartridge failed\n");
        if (request->op == TO_RUN)
            return tape_34xx_erp_failed(request, -EIO);
        return tape_34xx_erp_bug(device, request, irb, sense[3]);
    case 0x35:
        /*
         * Drive equipment check. One of the following:
         * - cu cannot recover from a drive detected error
         * - a check code message is shown on drive display
         * - the cartridge loader does not respond correctly
         * - a failure occurs during an index, load, or unload cycle
         */
        dev_warn (&device->cdev->dev, "An equipment check has occurred"
            " on the tape unit\n");
        return tape_34xx_erp_failed(request, -EIO);
    case 0x36:
        if (device->cdev->id.driver_info == tape_3490)
            /* End of data. */
            return tape_34xx_erp_failed(request, -EIO);
        /* This erpa is reserved for 3480 */
        return tape_34xx_erp_bug(device, request, irb, sense[3]);
    case 0x37:
        /*
         * Tape length error. The tape is shorter than reported in
         * the beginning-of-tape data.
         */
        dev_warn (&device->cdev->dev, "The tape information states an"
            " incorrect length\n");
        return tape_34xx_erp_failed(request, -EIO);
    case 0x38:
        /*
         * Physical end of tape. A read/write operation reached
         * the physical end of tape.
         */
        if (request->op==TO_WRI ||
            request->op==TO_DSE ||
            request->op==TO_WTM)
            return tape_34xx_erp_failed(request, -ENOSPC);
        return tape_34xx_erp_failed(request, -EIO);
    case 0x39:
        /* Backward at Beginning of tape. */
        return tape_34xx_erp_failed(request, -EIO);
    case 0x3a:
        /* Drive switched to not ready. */
        dev_warn (&device->cdev->dev, "The tape unit is not ready\n");
        return tape_34xx_erp_failed(request, -EIO);
    case 0x3b:
        /* Manual rewind or unload. This causes an I/O error. */
        dev_warn (&device->cdev->dev, "The tape medium has been "
            "rewound or unloaded manually\n");
        tape_34xx_delete_sbid_from(device, 0);
        return tape_34xx_erp_failed(request, -EIO);
    case 0x42:
        /*
         * Degraded mode. A condition that can cause degraded
         * performance is detected.
         */
        dev_warn (&device->cdev->dev, "The tape subsystem is running "
            "in degraded mode\n");
        return tape_34xx_erp_retry(request);
    case 0x43:
        /* Drive not ready. */
        tape_34xx_delete_sbid_from(device, 0);
        tape_med_state_set(device, MS_UNLOADED);
        /* Some commands commands are successful even in this case */
        if (sense[1] & SENSE_DRIVE_ONLINE) {
            switch(request->op) {
                case TO_ASSIGN:
                case TO_UNASSIGN:
                case TO_DIS:
                case TO_NOP:
                    return tape_34xx_done(request);
                    break;
                default:
                    break;
            }
        }
        return tape_34xx_erp_failed(request, -ENOMEDIUM);
    case 0x44:
        /* Locate Block unsuccessful. */
        if (request->op != TO_BLOCK && request->op != TO_LBL)
            /* No locate block was issued. */
            return tape_34xx_erp_bug(device, request,
                         irb, sense[3]);
        return tape_34xx_erp_failed(request, -EIO);
    case 0x45:
        /* The drive is assigned to a different channel path. */
        dev_warn (&device->cdev->dev, "The tape unit is already "
            "assigned\n");
        return tape_34xx_erp_failed(request, -EIO);
    case 0x46:
        /*
         * Drive not on-line. Drive may be switched offline,
         * the power supply may be switched off or
         * the drive address may not be set correctly.
         */
        dev_warn (&device->cdev->dev, "The tape unit is not online\n");
        return tape_34xx_erp_failed(request, -EIO);
    case 0x47:
        /* Volume fenced. CU reports volume integrity is lost. */
        dev_warn (&device->cdev->dev, "The control unit has fenced "
            "access to the tape volume\n");
        tape_34xx_delete_sbid_from(device, 0);
        return tape_34xx_erp_failed(request, -EIO);
    case 0x48:
        /* Log sense data and retry request. */
        return tape_34xx_erp_retry(request);
    case 0x49:
        /* Bus out check. A parity check error on the bus was found. */
        dev_warn (&device->cdev->dev, "A parity error occurred on the "
            "tape bus\n");
        return tape_34xx_erp_failed(request, -EIO);
    case 0x4a:
        /* Control unit erp failed. */
        dev_warn (&device->cdev->dev, "I/O error recovery failed on "
            "the tape control unit\n");
        return tape_34xx_erp_failed(request, -EIO);
    case 0x4b:
        /*
         * CU and drive incompatible. The drive requests micro-program
         * patches, which are not available on the CU.
         */
        dev_warn (&device->cdev->dev, "The tape unit requires a "
            "firmware update\n");
        return tape_34xx_erp_failed(request, -EIO);
    case 0x4c:
        /*
         * Recovered Check-One failure. Cu develops a hardware error,
         * but is able to recover.
         */
        return tape_34xx_erp_retry(request);
    case 0x4d:
        if (device->cdev->id.driver_info == tape_3490)
            /*
             * Resetting event received. Since the driver does
             * not support resetting event recovery (which has to
             * be handled by the I/O Layer), retry our command.
             */
            return tape_34xx_erp_retry(request);
        /* This erpa is reserved for 3480. */
        return tape_34xx_erp_bug(device, request, irb, sense[3]);
    case 0x4e:
        if (device->cdev->id.driver_info == tape_3490) {
            /*
             * Maximum block size exceeded. This indicates, that
             * the block to be written is larger than allowed for
             * buffered mode.
             */
            dev_warn (&device->cdev->dev, "The maximum block size"
                " for buffered mode is exceeded\n");
            return tape_34xx_erp_failed(request, -ENOBUFS);
        }
        /* This erpa is reserved for 3480. */
        return tape_34xx_erp_bug(device, request, irb, sense[3]);
    case 0x50:
        /*
         * Read buffered log (Overflow). CU is running in extended
         * buffered log mode, and a counter overflows. This should
         * never happen, since we're never running in extended
         * buffered log mode.
         */
        return tape_34xx_erp_retry(request);
    case 0x51:
        /*
         * Read buffered log (EOV). EOF processing occurs while the
         * CU is in extended buffered log mode. This should never
         * happen, since we're never running in extended buffered
         * log mode.
         */
        return tape_34xx_erp_retry(request);
    case 0x52:
        /* End of Volume complete. Rewind unload completed ok. */
        if (request->op == TO_RUN) {
            tape_med_state_set(device, MS_UNLOADED);
            tape_34xx_delete_sbid_from(device, 0);
            return tape_34xx_erp_succeeded(request);
        }
        return tape_34xx_erp_bug(device, request, irb, sense[3]);
    case 0x53:
        /* Global command intercept. */
        return tape_34xx_erp_retry(request);
    case 0x54:
        /* Channel interface recovery (temporary). */
        return tape_34xx_erp_retry(request);
    case 0x55:
        /* Channel interface recovery (permanent). */
        dev_warn (&device->cdev->dev, "A channel interface error cannot be"
            " recovered\n");
        return tape_34xx_erp_failed(request, -EIO);
    case 0x56:
        /* Channel protocol error. */
        dev_warn (&device->cdev->dev, "A channel protocol error "
            "occurred\n");
        return tape_34xx_erp_failed(request, -EIO);
    case 0x57:
        if (device->cdev->id.driver_info == tape_3480) {
            /* Attention intercept. */
            return tape_34xx_erp_retry(request);
        } else {
            /* Global status intercept. */
            return tape_34xx_erp_retry(request);
        }
    case 0x5a:
        /*
         * Tape length incompatible. The tape inserted is too long,
         * which could cause damage to the tape or the drive.
         */
        dev_warn (&device->cdev->dev, "The tape unit does not support "
            "the tape length\n");
        return tape_34xx_erp_failed(request, -EIO);
    case 0x5b:
        /* Format 3480 XF incompatible */
        if (sense[1] & SENSE_BEGINNING_OF_TAPE)
            /* The tape will get overwritten. */
            return tape_34xx_erp_retry(request);
        dev_warn (&device->cdev->dev, "The tape unit does not support"
            " format 3480 XF\n");
        return tape_34xx_erp_failed(request, -EIO);
    case 0x5c:
        /* Format 3480-2 XF incompatible */
        dev_warn (&device->cdev->dev, "The tape unit does not support tape "
            "format 3480-2 XF\n");
        return tape_34xx_erp_failed(request, -EIO);
    case 0x5d:
        /* Tape length violation. */
        dev_warn (&device->cdev->dev, "The tape unit does not support"
            " the current tape length\n");
        return tape_34xx_erp_failed(request, -EMEDIUMTYPE);
    case 0x5e:
        /* Compaction algorithm incompatible. */
        dev_warn (&device->cdev->dev, "The tape unit does not support"
            " the compaction algorithm\n");
        return tape_34xx_erp_failed(request, -EMEDIUMTYPE);

        /* The following erpas should have been covered earlier. */
    case 0x23: /* Read data check. */
    case 0x25: /* Write data check. */
    case 0x26: /* Data check (read opposite). */
    case 0x28: /* Write id mark check. */
    case 0x31: /* Tape void. */
    case 0x40: /* Overrun error. */
    case 0x41: /* Record sequence error. */
        /* All other erpas are reserved for future use. */
    default:
        return tape_34xx_erp_bug(device, request, irb, sense[3]);
    }
}

/*
 * 3480/3490 interrupt handler
 */
static int
tape_34xx_irq(struct tape_device *device, struct tape_request *request,
          struct irb *irb)
{
    if (request == NULL)
        return tape_34xx_unsolicited_irq(device, irb);

    if ((irb->scsw.cmd.dstat & DEV_STAT_UNIT_EXCEP) &&
        (irb->scsw.cmd.dstat & DEV_STAT_DEV_END) &&
        (request->op == TO_WRI)) {
        /* Write at end of volume */
        return tape_34xx_erp_failed(request, -ENOSPC);
    }

    if (irb->scsw.cmd.dstat & DEV_STAT_UNIT_CHECK)
        return tape_34xx_unit_check(device, request, irb);

    if (irb->scsw.cmd.dstat & DEV_STAT_DEV_END) {
        /*
         * A unit exception occurs on skipping over a tapemark block.
         */
        if (irb->scsw.cmd.dstat & DEV_STAT_UNIT_EXCEP) {
            if (request->op == TO_BSB || request->op == TO_FSB)
                request->rescnt++;
            else
                DBF_EVENT(5, "Unit Exception!\n");
        }
        return tape_34xx_done(request);
    }

    DBF_EVENT(6, "xunknownirq\n");
    tape_dump_sense_dbf(device, request, irb);
    return TAPE_IO_STOP;
}

/*
 * ioctl_overload
 */
static int
tape_34xx_ioctl(struct tape_device *device, unsigned int cmd, unsigned long arg)
{
    if (cmd == TAPE390_DISPLAY) {
        struct display_struct disp;

        if (copy_from_user(&disp, (char __user *) arg, sizeof(disp)) != 0)
            return -EFAULT;

        return tape_std_display(device, &disp);
    } else
        return -EINVAL;
}

static inline void
tape_34xx_append_new_sbid(struct tape_34xx_block_id bid, struct list_head *l)
{
    struct tape_34xx_sbid * new_sbid;

    new_sbid = kmalloc(sizeof(*new_sbid), GFP_ATOMIC);
    if (!new_sbid)
        return;

    new_sbid->bid = bid;
    list_add(&new_sbid->list, l);
}

/*
 * Build up the search block ID list. The block ID consists of a logical
 * block number and a hardware specific part. The hardware specific part
 * helps the tape drive to speed up searching for a specific block.
 */
static void
tape_34xx_add_sbid(struct tape_device *device, struct tape_34xx_block_id bid)
{
    struct list_head *  sbid_list;
    struct tape_34xx_sbid * sbid;
    struct list_head *  l;

    /*
     * immediately return if there is no list at all or the block to add
     * is located in segment 1 of wrap 0 because this position is used
     * if no hardware position data is supplied.
     */
    sbid_list = (struct list_head *) device->discdata;
    if (!sbid_list || (bid.segment < 2 && bid.wrap == 0))
        return;

    /*
     * Search the position where to insert the new entry. Hardware
     * acceleration uses only the segment and wrap number. So we
     * need only one entry for a specific wrap/segment combination.
     * If there is a block with a lower number but the same hard-
     * ware position data we just update the block number in the
     * existing entry.
     */
    list_for_each(l, sbid_list) {
        sbid = list_entry(l, struct tape_34xx_sbid, list);

        if (
            (sbid->bid.segment == bid.segment) &&
            (sbid->bid.wrap    == bid.wrap)
        ) {
            if (bid.block < sbid->bid.block)
                sbid->bid = bid;
            else return;
            break;
        }

        /* Sort in according to logical block number. */
        if (bid.block < sbid->bid.block) {
            tape_34xx_append_new_sbid(bid, l->prev);
            break;
        }
    }
    /* List empty or new block bigger than last entry. */
    if (l == sbid_list)
        tape_34xx_append_new_sbid(bid, l->prev);

    DBF_LH(4, "Current list is:\n");
    list_for_each(l, sbid_list) {
        sbid = list_entry(l, struct tape_34xx_sbid, list);
        DBF_LH(4, "%d:%03d@%05d\n",
            sbid->bid.wrap,
            sbid->bid.segment,
            sbid->bid.block
        );
    }
}

/*
 * Delete all entries from the search block ID list that belong to tape blocks
 * equal or higher than the given number.
 */
static void
tape_34xx_delete_sbid_from(struct tape_device *device, int from)
{
    struct list_head *  sbid_list;
    struct tape_34xx_sbid * sbid;
    struct list_head *  l;
    struct list_head *  n;

    sbid_list = (struct list_head *) device->discdata;
    if (!sbid_list)
        return;

    list_for_each_safe(l, n, sbid_list) {
        sbid = list_entry(l, struct tape_34xx_sbid, list);
        if (sbid->bid.block >= from) {
            DBF_LH(4, "Delete sbid %d:%03d@%05d\n",
                sbid->bid.wrap,
                sbid->bid.segment,
                sbid->bid.block
            );
            list_del(l);
            kfree(sbid);
        }
    }
}

/*
 * Merge hardware position data into a block id.
 */
static void
tape_34xx_merge_sbid(
    struct tape_device *        device,
    struct tape_34xx_block_id * bid
) {
    struct tape_34xx_sbid * sbid;
    struct tape_34xx_sbid * sbid_to_use;
    struct list_head *  sbid_list;
    struct list_head *  l;

    sbid_list = (struct list_head *) device->discdata;
    bid->wrap    = 0;
    bid->segment = 1;

    if (!sbid_list || list_empty(sbid_list))
        return;

    sbid_to_use = NULL;
    list_for_each(l, sbid_list) {
        sbid = list_entry(l, struct tape_34xx_sbid, list);

        if (sbid->bid.block >= bid->block)
            break;
        sbid_to_use = sbid;
    }
    if (sbid_to_use) {
        bid->wrap    = sbid_to_use->bid.wrap;
        bid->segment = sbid_to_use->bid.segment;
        DBF_LH(4, "Use %d:%03d@%05d for %05d\n",
            sbid_to_use->bid.wrap,
            sbid_to_use->bid.segment,
            sbid_to_use->bid.block,
            bid->block
        );
    }
}

static int
tape_34xx_setup_device(struct tape_device * device)
{
    int         rc;
    struct list_head *  discdata;

    DBF_EVENT(6, "34xx device setup\n");
    if ((rc = tape_std_assign(device)) == 0) {
        if ((rc = tape_34xx_medium_sense(device)) != 0) {
            DBF_LH(3, "34xx medium sense returned %d\n", rc);
        }
    }
    discdata = kmalloc(sizeof(struct list_head), GFP_KERNEL);
    if (discdata) {
            INIT_LIST_HEAD(discdata);
            device->discdata = discdata;
    }

    return rc;
}

static void
tape_34xx_cleanup_device(struct tape_device *device)
{
    tape_std_unassign(device);
    
    if (device->discdata) {
        tape_34xx_delete_sbid_from(device, 0);
        kfree(device->discdata);
        device->discdata = NULL;
    }
}


/*
 * MTTELL: Tell block. Return the number of block relative to current file.
 */
static int
tape_34xx_mttell(struct tape_device *device, int mt_count)
{
    struct {
        struct tape_34xx_block_id   cbid;
        struct tape_34xx_block_id   dbid;
    } __attribute__ ((packed)) block_id;
    int rc;

    rc = tape_std_read_block_id(device, (__u64 *) &block_id);
    if (rc)
        return rc;

    tape_34xx_add_sbid(device, block_id.cbid);
    return block_id.cbid.block;
}

/*
 * MTSEEK: seek to the specified block.
 */
static int
tape_34xx_mtseek(struct tape_device *device, int mt_count)
{
    struct tape_request *request;
    struct tape_34xx_block_id * bid;

    if (mt_count > 0x3fffff) {
        DBF_EXCEPTION(6, "xsee parm\n");
        return -EINVAL;
    }
    request = tape_alloc_request(3, 4);
    if (IS_ERR(request))
        return PTR_ERR(request);

    /* setup ccws */
    request->op = TO_LBL;
    bid         = (struct tape_34xx_block_id *) request->cpdata;
    bid->format = (*device->modeset_byte & 0x08) ?
            TAPE34XX_FMT_3480_XF : TAPE34XX_FMT_3480;
    bid->block  = mt_count;
    tape_34xx_merge_sbid(device, bid);

    tape_ccw_cc(request->cpaddr, MODE_SET_DB, 1, device->modeset_byte);
    tape_ccw_cc(request->cpaddr + 1, LOCATE, 4, request->cpdata);
    tape_ccw_end(request->cpaddr + 2, NOP, 0, NULL);

    /* execute it */
    return tape_do_io_free(device, request);
}

/*
 * List of 3480/3490 magnetic tape commands.
 */
static tape_mtop_fn tape_34xx_mtop[TAPE_NR_MTOPS] = {
    [MTRESET]    = tape_std_mtreset,
    [MTFSF]      = tape_std_mtfsf,
    [MTBSF]      = tape_std_mtbsf,
    [MTFSR]      = tape_std_mtfsr,
    [MTBSR]      = tape_std_mtbsr,
    [MTWEOF]     = tape_std_mtweof,
    [MTREW]      = tape_std_mtrew,
    [MTOFFL]     = tape_std_mtoffl,
    [MTNOP]      = tape_std_mtnop,
    [MTRETEN]    = tape_std_mtreten,
    [MTBSFM]     = tape_std_mtbsfm,
    [MTFSFM]     = tape_std_mtfsfm,
    [MTEOM]      = tape_std_mteom,
    [MTERASE]    = tape_std_mterase,
    [MTRAS1]     = NULL,
    [MTRAS2]     = NULL,
    [MTRAS3]     = NULL,
    [MTSETBLK]   = tape_std_mtsetblk,
    [MTSETDENSITY]   = NULL,
    [MTSEEK]     = tape_34xx_mtseek,
    [MTTELL]     = tape_34xx_mttell,
    [MTSETDRVBUFFER] = NULL,
    [MTFSS]      = NULL,
    [MTBSS]      = NULL,
    [MTWSM]      = NULL,
    [MTLOCK]     = NULL,
    [MTUNLOCK]   = NULL,
    [MTLOAD]     = tape_std_mtload,
    [MTUNLOAD]   = tape_std_mtunload,
    [MTCOMPRESSION]  = tape_std_mtcompression,
    [MTSETPART]  = NULL,
    [MTMKPART]   = NULL
};

/*
 * Tape discipline structure for 3480 and 3490.
 */
static struct tape_discipline tape_discipline_34xx = {
    .owner = THIS_MODULE,
    .setup_device = tape_34xx_setup_device,
    .cleanup_device = tape_34xx_cleanup_device,
    .process_eov = tape_std_process_eov,
    .irq = tape_34xx_irq,
    .read_block = tape_std_read_block,
    .write_block = tape_std_write_block,
    .ioctl_fn = tape_34xx_ioctl,
    .mtop_array = tape_34xx_mtop
};

static struct ccw_device_id tape_34xx_ids[] = {
    { CCW_DEVICE_DEVTYPE(0x3480, 0, 0x3480, 0), .driver_info = tape_3480},
    { CCW_DEVICE_DEVTYPE(0x3490, 0, 0x3490, 0), .driver_info = tape_3490},
    { /* end of list */ },
};

static int
tape_34xx_online(struct ccw_device *cdev)
{
    return tape_generic_online(
        dev_get_drvdata(&cdev->dev),
        &tape_discipline_34xx
    );
}

static struct ccw_driver tape_34xx_driver = {
    .driver = {
        .name = "tape_34xx",
        .owner = THIS_MODULE,
    },
    .ids = tape_34xx_ids,
    .probe = tape_generic_probe,
    .remove = tape_generic_remove,
    .set_online = tape_34xx_online,
    .set_offline = tape_generic_offline,
    .freeze = tape_generic_pm_suspend,
    .int_class = IOINT_TAP,
};

static int
tape_34xx_init (void)
{
    int rc;

    TAPE_DBF_AREA = debug_register ( "tape_34xx", 2, 2, 4*sizeof(long));
    debug_register_view(TAPE_DBF_AREA, &debug_sprintf_view);
#ifdef DBF_LIKE_HELL
    debug_set_level(TAPE_DBF_AREA, 6);
#endif

    DBF_EVENT(3, "34xx init\n");
    /* Register driver for 3480/3490 tapes. */
    rc = ccw_driver_register(&tape_34xx_driver);
    if (rc)
        DBF_EVENT(3, "34xx init failed\n");
    else
        DBF_EVENT(3, "34xx registered\n");
    return rc;
}

static void
tape_34xx_exit(void)
{
    ccw_driver_unregister(&tape_34xx_driver);

    debug_unregister(TAPE_DBF_AREA);
}

MODULE_DEVICE_TABLE(ccw, tape_34xx_ids);
MODULE_AUTHOR("(C) 2001-2002 IBM Deutschland Entwicklung GmbH");
MODULE_DESCRIPTION("Linux on zSeries channel attached 3480 tape device driver");
MODULE_LICENSE("GPL");

module_init(tape_34xx_init);
module_exit(tape_34xx_exit);