/*
 * File...........: linux/drivers/s390/block/dasd_3990_erp.c
 * Author(s)......: Horst  Hummel    <Horst.Hummel@de.ibm.com>
 *                  Holger Smolinski <Holger.Smolinski@de.ibm.com>
 * Bugreports.to..: <Linux390@de.ibm.com>
 * (C) IBM Corporation, IBM Deutschland Entwicklung GmbH, 2000, 2001
 *
 */

#define KMSG_COMPONENT "dasd-eckd"

#include <linux/timer.h>
#include <asm/idals.h>

#define PRINTK_HEADER "dasd_erp(3990): "

#include "dasd_int.h"
#include "dasd_eckd.h"


struct DCTL_data {
        unsigned char subcommand;  /* e.g Inhibit Write, Enable Write,... */
        unsigned char modifier;    /* Subcommand modifier */
        unsigned short res;        /* reserved */
} __attribute__ ((packed));

/*
 *****************************************************************************
 * SECTION ERP HANDLING
 *****************************************************************************
 */
/*
 *****************************************************************************
 * 24 and 32 byte sense ERP functions
 *****************************************************************************
 */

/*
 * DASD_3990_ERP_CLEANUP
 *
 * DESCRIPTION
 *   Removes the already build but not necessary ERP request and sets
 *   the status of the original cqr / erp to the given (final) status
 *
 *  PARAMETER
 *   erp                request to be blocked
 *   final_status       either DASD_CQR_DONE or DASD_CQR_FAILED
 *
 * RETURN VALUES
 *   cqr                original cqr
 */
static struct dasd_ccw_req *
dasd_3990_erp_cleanup(struct dasd_ccw_req * erp, char final_status)
{
        struct dasd_ccw_req *cqr = erp->refers;

        dasd_free_erp_request(erp, erp->memdev);
        cqr->status = final_status;
        return cqr;

}                               /* end dasd_3990_erp_cleanup */

/*
 * DASD_3990_ERP_BLOCK_QUEUE
 *
 * DESCRIPTION
 *   Block the given device request queue to prevent from further
 *   processing until the started timer has expired or an related
 *   interrupt was received.
 */
static void dasd_3990_erp_block_queue(struct dasd_ccw_req *erp, int expires)
{

        struct dasd_device *device = erp->startdev;
        unsigned long flags;

        DBF_DEV_EVENT(DBF_INFO, device,
                    "blocking request queue for %is", expires/HZ);

        spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
        dasd_device_set_stop_bits(device, DASD_STOPPED_PENDING);
        spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
        erp->status = DASD_CQR_FILLED;
        if (erp->block)
                dasd_block_set_timer(erp->block, expires);
        else
                dasd_device_set_timer(device, expires);
}

/*
 * DASD_3990_ERP_INT_REQ
 *
 * DESCRIPTION
 *   Handles 'Intervention Required' error.
 *   This means either device offline or not installed.
 *
 * PARAMETER
 *   erp                current erp
 * RETURN VALUES
 *   erp                modified erp
 */
static struct dasd_ccw_req *
dasd_3990_erp_int_req(struct dasd_ccw_req * erp)
{

        struct dasd_device *device = erp->startdev;

        /* first time set initial retry counter and erp_function */
        /* and retry once without blocking queue                 */
        /* (this enables easier enqueing of the cqr)             */
        if (erp->function != dasd_3990_erp_int_req) {

                erp->retries = 256;
                erp->function = dasd_3990_erp_int_req;

        } else {

                /* issue a message and wait for 'device ready' interrupt */
                dev_err(&device->cdev->dev,
                            "is offline or not installed - "
                            "INTERVENTION REQUIRED!!\n");

                dasd_3990_erp_block_queue(erp, 60*HZ);
        }

        return erp;

}                               /* end dasd_3990_erp_int_req */

/*
 * DASD_3990_ERP_ALTERNATE_PATH
 *
 * DESCRIPTION
 *   Repeat the operation on a different channel path.
 *   If all alternate paths have been tried, the request is posted with a
 *   permanent error.
 *
 *  PARAMETER
 *   erp                pointer to the current ERP
 *
 * RETURN VALUES
 *   erp                modified pointer to the ERP
 */
static void
dasd_3990_erp_alternate_path(struct dasd_ccw_req * erp)
{
        struct dasd_device *device = erp->startdev;
        __u8 opm;
        unsigned long flags;

        /* try alternate valid path */
        spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
        opm = ccw_device_get_path_mask(device->cdev);
        spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
        if (erp->lpm == 0)
                erp->lpm = device->path_data.opm &
                        ~(erp->irb.esw.esw0.sublog.lpum);
        else
                erp->lpm &= ~(erp->irb.esw.esw0.sublog.lpum);

        if ((erp->lpm & opm) != 0x00) {

                DBF_DEV_EVENT(DBF_WARNING, device,
                            "try alternate lpm=%x (lpum=%x / opm=%x)",
                            erp->lpm, erp->irb.esw.esw0.sublog.lpum, opm);

                /* reset status to submit the request again... */
                erp->status = DASD_CQR_FILLED;
                erp->retries = 10;
        } else {
                dev_err(&device->cdev->dev,
                        "The DASD cannot be reached on any path (lpum=%x"
                        "/opm=%x)\n", erp->irb.esw.esw0.sublog.lpum, opm);

                /* post request with permanent error */
                erp->status = DASD_CQR_FAILED;
        }
}                               /* end dasd_3990_erp_alternate_path */

/*
 * DASD_3990_ERP_DCTL
 *
 * DESCRIPTION
 *   Setup cqr to do the Diagnostic Control (DCTL) command with an
 *   Inhibit Write subcommand (0x20) and the given modifier.
 *
 *  PARAMETER
 *   erp                pointer to the current (failed) ERP
 *   modifier           subcommand modifier
 *
 * RETURN VALUES
 *   dctl_cqr           pointer to NEW dctl_cqr
 *
 */
static struct dasd_ccw_req *
dasd_3990_erp_DCTL(struct dasd_ccw_req * erp, char modifier)
{

        struct dasd_device *device = erp->startdev;
        struct DCTL_data *DCTL_data;
        struct ccw1 *ccw;
        struct dasd_ccw_req *dctl_cqr;

        dctl_cqr = dasd_alloc_erp_request((char *) &erp->magic, 1,
                                          sizeof(struct DCTL_data),
                                          device);
        if (IS_ERR(dctl_cqr)) {
                dev_err(&device->cdev->dev,
                            "Unable to allocate DCTL-CQR\n");
                erp->status = DASD_CQR_FAILED;
                return erp;
        }

        DCTL_data = dctl_cqr->data;

        DCTL_data->subcommand = 0x02;   /* Inhibit Write */
        DCTL_data->modifier = modifier;

        ccw = dctl_cqr->cpaddr;
        memset(ccw, 0, sizeof(struct ccw1));
        ccw->cmd_code = CCW_CMD_DCTL;
        ccw->count = 4;
        ccw->cda = (__u32)(addr_t) DCTL_data;
        dctl_cqr->flags = erp->flags;
        dctl_cqr->function = dasd_3990_erp_DCTL;
        dctl_cqr->refers = erp;
        dctl_cqr->startdev = device;
        dctl_cqr->memdev = device;
        dctl_cqr->magic = erp->magic;
        dctl_cqr->expires = 5 * 60 * HZ;
        dctl_cqr->retries = 2;

        dctl_cqr->buildclk = get_clock();

        dctl_cqr->status = DASD_CQR_FILLED;

        return dctl_cqr;

}                               /* end dasd_3990_erp_DCTL */

/*
 * DASD_3990_ERP_ACTION_1
 *
 * DESCRIPTION
 *   Setup ERP to do the ERP action 1 (see Reference manual).
 *   Repeat the operation on a different channel path.
 *   As deviation from the recommended recovery action, we reset the path mask
 *   after we have tried each path and go through all paths a second time.
 *   This will cover situations where only one path at a time is actually down,
 *   but all paths fail and recover just with the same sequence and timing as
 *   we try to use them (flapping links).
 *   If all alternate paths have been tried twice, the request is posted with
 *   a permanent error.
 *
 *  PARAMETER
 *   erp                pointer to the current ERP
 *
 * RETURN VALUES
 *   erp                pointer to the ERP
 *
 */
static struct dasd_ccw_req *dasd_3990_erp_action_1_sec(struct dasd_ccw_req *erp)
{
        erp->function = dasd_3990_erp_action_1_sec;
        dasd_3990_erp_alternate_path(erp);
        return erp;
}

static struct dasd_ccw_req *dasd_3990_erp_action_1(struct dasd_ccw_req *erp)
{
        erp->function = dasd_3990_erp_action_1;
        dasd_3990_erp_alternate_path(erp);
        if (erp->status == DASD_CQR_FAILED &&
            !test_bit(DASD_CQR_VERIFY_PATH, &erp->flags)) {
                erp->status = DASD_CQR_FILLED;
                erp->retries = 10;
                erp->lpm = erp->startdev->path_data.opm;
                erp->function = dasd_3990_erp_action_1_sec;
        }
        return erp;
}                               /* end dasd_3990_erp_action_1(b) */

/*
 * DASD_3990_ERP_ACTION_4
 *
 * DESCRIPTION
 *   Setup ERP to do the ERP action 4 (see Reference manual).
 *   Set the current request to PENDING to block the CQR queue for that device
 *   until the state change interrupt appears.
 *   Use a timer (20 seconds) to retry the cqr if the interrupt is still
 *   missing.
 *
 *  PARAMETER
 *   sense              sense data of the actual error
 *   erp                pointer to the current ERP
 *
 * RETURN VALUES
 *   erp                pointer to the ERP
 *
 */
static struct dasd_ccw_req *
dasd_3990_erp_action_4(struct dasd_ccw_req * erp, char *sense)
{

        struct dasd_device *device = erp->startdev;

        /* first time set initial retry counter and erp_function    */
        /* and retry once without waiting for state change pending  */
        /* interrupt (this enables easier enqueing of the cqr)      */
        if (erp->function != dasd_3990_erp_action_4) {

                DBF_DEV_EVENT(DBF_INFO, device, "%s",
                            "dasd_3990_erp_action_4: first time retry");

                erp->retries = 256;
                erp->function = dasd_3990_erp_action_4;

        } else {
                if (sense && (sense[25] == 0x1D)) { /* state change pending */

                        DBF_DEV_EVENT(DBF_INFO, device,
                                    "waiting for state change pending "
                                    "interrupt, %d retries left",
                                    erp->retries);

                        dasd_3990_erp_block_queue(erp, 30*HZ);

                } else if (sense && (sense[25] == 0x1E)) {      /* busy */
                        DBF_DEV_EVENT(DBF_INFO, device,
                                    "busy - redriving request later, "
                                    "%d retries left",
                                    erp->retries);
                        dasd_3990_erp_block_queue(erp, HZ);
                } else {
                        /* no state change pending - retry */
                        DBF_DEV_EVENT(DBF_INFO, device,
                                     "redriving request immediately, "
                                     "%d retries left",
                                     erp->retries);
                        erp->status = DASD_CQR_FILLED;
                }
        }

        return erp;

}                               /* end dasd_3990_erp_action_4 */

/*
 *****************************************************************************
 * 24 byte sense ERP functions (only)
 *****************************************************************************
 */

/*
 * DASD_3990_ERP_ACTION_5
 *
 * DESCRIPTION
 *   Setup ERP to do the ERP action 5 (see Reference manual).
 *   NOTE: Further handling is done in xxx_further_erp after the retries.
 *
 *  PARAMETER
 *   erp                pointer to the current ERP
 *
 * RETURN VALUES
 *   erp                pointer to the ERP
 *
 */
static struct dasd_ccw_req *
dasd_3990_erp_action_5(struct dasd_ccw_req * erp)
{

        /* first of all retry */
        erp->retries = 10;
        erp->function = dasd_3990_erp_action_5;

        return erp;

}                               /* end dasd_3990_erp_action_5 */

/*
 * DASD_3990_HANDLE_ENV_DATA
 *
 * DESCRIPTION
 *   Handles 24 byte 'Environmental data present'.
 *   Does a analysis of the sense data (message Format)
 *   and prints the error messages.
 *
 * PARAMETER
 *   sense              current sense data
 *
 * RETURN VALUES
 *   void
 */
static void
dasd_3990_handle_env_data(struct dasd_ccw_req * erp, char *sense)
{

        struct dasd_device *device = erp->startdev;
        char msg_format = (sense[7] & 0xF0);
        char msg_no = (sense[7] & 0x0F);
        char errorstring[ERRORLENGTH];

        switch (msg_format) {
        case 0x00:              /* Format 0 - Program or System Checks */

                if (sense[1] & 0x10) {  /* check message to operator bit */

                        switch (msg_no) {
                        case 0x00:      /* No Message */
                                break;
                        case 0x01:
                                dev_warn(&device->cdev->dev,
                                            "FORMAT 0 - Invalid Command\n");
                                break;
                        case 0x02:
                                dev_warn(&device->cdev->dev,
                                            "FORMAT 0 - Invalid Command "
                                            "Sequence\n");
                                break;
                        case 0x03:
                                dev_warn(&device->cdev->dev,
                                            "FORMAT 0 - CCW Count less than "
                                            "required\n");
                                break;
                        case 0x04:
                                dev_warn(&device->cdev->dev,
                                            "FORMAT 0 - Invalid Parameter\n");
                                break;
                        case 0x05:
                                dev_warn(&device->cdev->dev,
                                            "FORMAT 0 - Diagnostic of Special"
                                            " Command Violates File Mask\n");
                                break;
                        case 0x07:
                                dev_warn(&device->cdev->dev,
                                            "FORMAT 0 - Channel Returned with "
                                            "Incorrect retry CCW\n");
                                break;
                        case 0x08:
                                dev_warn(&device->cdev->dev,
                                            "FORMAT 0 - Reset Notification\n");
                                break;
                        case 0x09:
                                dev_warn(&device->cdev->dev,
                                         "FORMAT 0 - Storage Path Restart\n");
                                break;
                        case 0x0A:
                                dev_warn(&device->cdev->dev,
                                            "FORMAT 0 - Channel requested "
                                            "... %02x\n", sense[8]);
                                break;
                        case 0x0B:
                                dev_warn(&device->cdev->dev,
                                            "FORMAT 0 - Invalid Defective/"
                                            "Alternate Track Pointer\n");
                                break;
                        case 0x0C:
                                dev_warn(&device->cdev->dev,
                                            "FORMAT 0 - DPS Installation "
                                            "Check\n");
                                break;
                        case 0x0E:
                                dev_warn(&device->cdev->dev,
                                            "FORMAT 0 - Command Invalid on "
                                            "Secondary Address\n");
                                break;
                        case 0x0F:
                                dev_warn(&device->cdev->dev,
                                            "FORMAT 0 - Status Not As "
                                            "Required: reason %02x\n",
                                         sense[8]);
                                break;
                        default:
                                dev_warn(&device->cdev->dev,
                                            "FORMAT 0 - Reserved\n");
                        }
                } else {
                        switch (msg_no) {
                        case 0x00:      /* No Message */
                                break;
                        case 0x01:
                                dev_warn(&device->cdev->dev,
                                         "FORMAT 0 - Device Error "
                                         "Source\n");
                                break;
                        case 0x02:
                                dev_warn(&device->cdev->dev,
                                            "FORMAT 0 - Reserved\n");
                                break;
                        case 0x03:
                                dev_warn(&device->cdev->dev,
                                            "FORMAT 0 - Device Fenced - "
                                            "device = %02x\n", sense[4]);
                                break;
                        case 0x04:
                                dev_warn(&device->cdev->dev,
                                            "FORMAT 0 - Data Pinned for "
                                            "Device\n");
                                break;
                        default:
                                dev_warn(&device->cdev->dev,
                                            "FORMAT 0 - Reserved\n");
                        }
                }
                break;

        case 0x10:              /* Format 1 - Device Equipment Checks */
                switch (msg_no) {
                case 0x00:      /* No Message */
                        break;
                case 0x01:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 1 - Device Status 1 not as "
                                    "expected\n");
                        break;
                case 0x03:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 1 - Index missing\n");
                        break;
                case 0x04:
                        dev_warn(&device->cdev->dev,
                                 "FORMAT 1 - Interruption cannot be "
                                 "reset\n");
                        break;
                case 0x05:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 1 - Device did not respond to "
                                    "selection\n");
                        break;
                case 0x06:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 1 - Device check-2 error or Set "
                                    "Sector is not complete\n");
                        break;
                case 0x07:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 1 - Head address does not "
                                    "compare\n");
                        break;
                case 0x08:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 1 - Device status 1 not valid\n");
                        break;
                case 0x09:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 1 - Device not ready\n");
                        break;
                case 0x0A:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 1 - Track physical address did "
                                    "not compare\n");
                        break;
                case 0x0B:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 1 - Missing device address bit\n");
                        break;
                case 0x0C:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 1 - Drive motor switch is off\n");
                        break;
                case 0x0D:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 1 - Seek incomplete\n");
                        break;
                case 0x0E:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 1 - Cylinder address did not "
                                    "compare\n");
                        break;
                case 0x0F:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 1 - Offset active cannot be "
                                    "reset\n");
                        break;
                default:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 1 - Reserved\n");
                }
                break;

        case 0x20:              /* Format 2 - 3990 Equipment Checks */
                switch (msg_no) {
                case 0x08:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 2 - 3990 check-2 error\n");
                        break;
                case 0x0E:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 2 - Support facility errors\n");
                        break;
                case 0x0F:
                        dev_warn(&device->cdev->dev,
                                 "FORMAT 2 - Microcode detected error "
                                 "%02x\n",
                                 sense[8]);
                        break;
                default:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 2 - Reserved\n");
                }
                break;

        case 0x30:              /* Format 3 - 3990 Control Checks */
                switch (msg_no) {
                case 0x0F:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 3 - Allegiance terminated\n");
                        break;
                default:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 3 - Reserved\n");
                }
                break;

        case 0x40:              /* Format 4 - Data Checks */
                switch (msg_no) {
                case 0x00:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 4 - Home address area error\n");
                        break;
                case 0x01:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 4 - Count area error\n");
                        break;
                case 0x02:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 4 - Key area error\n");
                        break;
                case 0x03:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 4 - Data area error\n");
                        break;
                case 0x04:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 4 - No sync byte in home address "
                                    "area\n");
                        break;
                case 0x05:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 4 - No sync byte in count address "
                                    "area\n");
                        break;
                case 0x06:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 4 - No sync byte in key area\n");
                        break;
                case 0x07:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 4 - No sync byte in data area\n");
                        break;
                case 0x08:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 4 - Home address area error; "
                                    "offset active\n");
                        break;
                case 0x09:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 4 - Count area error; offset "
                                    "active\n");
                        break;
                case 0x0A:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 4 - Key area error; offset "
                                    "active\n");
                        break;
                case 0x0B:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 4 - Data area error; "
                                    "offset active\n");
                        break;
                case 0x0C:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 4 - No sync byte in home "
                                    "address area; offset active\n");
                        break;
                case 0x0D:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 4 - No syn byte in count "
                                    "address area; offset active\n");
                        break;
                case 0x0E:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 4 - No sync byte in key area; "
                                    "offset active\n");
                        break;
                case 0x0F:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 4 - No syn byte in data area; "
                                    "offset active\n");
                        break;
                default:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 4 - Reserved\n");
                }
                break;

        case 0x50:  /* Format 5 - Data Check with displacement information */
                switch (msg_no) {
                case 0x00:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 5 - Data Check in the "
                                    "home address area\n");
                        break;
                case 0x01:
                        dev_warn(&device->cdev->dev,
                                 "FORMAT 5 - Data Check in the count "
                                 "area\n");
                        break;
                case 0x02:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 5 - Data Check in the key area\n");
                        break;
                case 0x03:
                        dev_warn(&device->cdev->dev,
                                 "FORMAT 5 - Data Check in the data "
                                 "area\n");
                        break;
                case 0x08:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 5 - Data Check in the "
                                    "home address area; offset active\n");
                        break;
                case 0x09:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 5 - Data Check in the count area; "
                                    "offset active\n");
                        break;
                case 0x0A:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 5 - Data Check in the key area; "
                                    "offset active\n");
                        break;
                case 0x0B:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 5 - Data Check in the data area; "
                                    "offset active\n");
                        break;
                default:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 5 - Reserved\n");
                }
                break;

        case 0x60:  /* Format 6 - Usage Statistics/Overrun Errors */
                switch (msg_no) {
                case 0x00:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 6 - Overrun on channel A\n");
                        break;
                case 0x01:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 6 - Overrun on channel B\n");
                        break;
                case 0x02:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 6 - Overrun on channel C\n");
                        break;
                case 0x03:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 6 - Overrun on channel D\n");
                        break;
                case 0x04:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 6 - Overrun on channel E\n");
                        break;
                case 0x05:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 6 - Overrun on channel F\n");
                        break;
                case 0x06:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 6 - Overrun on channel G\n");
                        break;
                case 0x07:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 6 - Overrun on channel H\n");
                        break;
                default:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 6 - Reserved\n");
                }
                break;

        case 0x70:  /* Format 7 - Device Connection Control Checks */
                switch (msg_no) {
                case 0x00:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 7 - RCC initiated by a connection "
                                    "check alert\n");
                        break;
                case 0x01:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 7 - RCC 1 sequence not "
                                    "successful\n");
                        break;
                case 0x02:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 7 - RCC 1 and RCC 2 sequences not "
                                    "successful\n");
                        break;
                case 0x03:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 7 - Invalid tag-in during "
                                    "selection sequence\n");
                        break;
                case 0x04:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 7 - extra RCC required\n");
                        break;
                case 0x05:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 7 - Invalid DCC selection "
                                    "response or timeout\n");
                        break;
                case 0x06:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 7 - Missing end operation; device "
                                    "transfer complete\n");
                        break;
                case 0x07:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 7 - Missing end operation; device "
                                    "transfer incomplete\n");
                        break;
                case 0x08:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 7 - Invalid tag-in for an "
                                    "immediate command sequence\n");
                        break;
                case 0x09:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 7 - Invalid tag-in for an "
                                    "extended command sequence\n");
                        break;
                case 0x0A:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 7 - 3990 microcode time out when "
                                    "stopping selection\n");
                        break;
                case 0x0B:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 7 - No response to selection "
                                    "after a poll interruption\n");
                        break;
                case 0x0C:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 7 - Permanent path error (DASD "
                                    "controller not available)\n");
                        break;
                case 0x0D:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 7 - DASD controller not available"
                                    " on disconnected command chain\n");
                        break;
                default:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 7 - Reserved\n");
                }
                break;

        case 0x80:  /* Format 8 - Additional Device Equipment Checks */
                switch (msg_no) {
                case 0x00:      /* No Message */
                case 0x01:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 8 - Error correction code "
                                    "hardware fault\n");
                        break;
                case 0x03:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 8 - Unexpected end operation "
                                    "response code\n");
                        break;
                case 0x04:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 8 - End operation with transfer "
                                    "count not zero\n");
                        break;
                case 0x05:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 8 - End operation with transfer "
                                    "count zero\n");
                        break;
                case 0x06:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 8 - DPS checks after a system "
                                    "reset or selective reset\n");
                        break;
                case 0x07:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 8 - DPS cannot be filled\n");
                        break;
                case 0x08:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 8 - Short busy time-out during "
                                    "device selection\n");
                        break;
                case 0x09:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 8 - DASD controller failed to "
                                    "set or reset the long busy latch\n");
                        break;
                case 0x0A:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 8 - No interruption from device "
                                    "during a command chain\n");
                        break;
                default:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 8 - Reserved\n");
                }
                break;

        case 0x90:  /* Format 9 - Device Read, Write, and Seek Checks */
                switch (msg_no) {
                case 0x00:
                        break;  /* No Message */
                case 0x06:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 9 - Device check-2 error\n");
                        break;
                case 0x07:
                        dev_warn(&device->cdev->dev,
                                 "FORMAT 9 - Head address did not "
                                 "compare\n");
                        break;
                case 0x0A:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 9 - Track physical address did "
                                    "not compare while oriented\n");
                        break;
                case 0x0E:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 9 - Cylinder address did not "
                                    "compare\n");
                        break;
                default:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT 9 - Reserved\n");
                }
                break;

        case 0xF0:              /* Format F - Cache Storage Checks */
                switch (msg_no) {
                case 0x00:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT F - Operation Terminated\n");
                        break;
                case 0x01:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT F - Subsystem Processing Error\n");
                        break;
                case 0x02:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT F - Cache or nonvolatile storage "
                                    "equipment failure\n");
                        break;
                case 0x04:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT F - Caching terminated\n");
                        break;
                case 0x06:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT F - Cache fast write access not "
                                    "authorized\n");
                        break;
                case 0x07:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT F - Track format incorrect\n");
                        break;
                case 0x09:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT F - Caching reinitiated\n");
                        break;
                case 0x0A:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT F - Nonvolatile storage "
                                    "terminated\n");
                        break;
                case 0x0B:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT F - Volume is suspended duplex\n");
                        /* call extended error reporting (EER) */
                        dasd_eer_write(device, erp->refers,
                                       DASD_EER_PPRCSUSPEND);
                        break;
                case 0x0C:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT F - Subsystem status cannot be "
                                    "determined\n");
                        break;
                case 0x0D:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT F - Caching status reset to "
                                    "default\n");
                        break;
                case 0x0E:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT F - DASD Fast Write inhibited\n");
                        break;

                default:
                        dev_warn(&device->cdev->dev,
                                    "FORMAT D - Reserved\n");
                }
                break;

        default:        /* unknown message format - should not happen
                           internal error 03 - unknown message format */
                snprintf(errorstring, ERRORLENGTH, "03 %x02", msg_format);
                dev_err(&device->cdev->dev,
                         "An error occurred in the DASD device driver, "
                         "reason=%s\n", errorstring);
                break;
        }                       /* end switch message format */

}                               /* end dasd_3990_handle_env_data */

/*
 * DASD_3990_ERP_COM_REJ
 *
 * DESCRIPTION
 *   Handles 24 byte 'Command Reject' error.
 *
 * PARAMETER
 *   erp                current erp_head
 *   sense              current sense data
 *
 * RETURN VALUES
 *   erp                'new' erp_head - pointer to new ERP
 */
static struct dasd_ccw_req *
dasd_3990_erp_com_rej(struct dasd_ccw_req * erp, char *sense)
{

        struct dasd_device *device = erp->startdev;

        erp->function = dasd_3990_erp_com_rej;

        /* env data present (ACTION 10 - retry should work) */
        if (sense[2] & SNS2_ENV_DATA_PRESENT) {

                DBF_DEV_EVENT(DBF_WARNING, device, "%s",
                            "Command Reject - environmental data present");

                dasd_3990_handle_env_data(erp, sense);

                erp->retries = 5;

        } else if (sense[1] & SNS1_WRITE_INHIBITED) {
                dev_err(&device->cdev->dev, "An I/O request was rejected"
                        " because writing is inhibited\n");
                erp = dasd_3990_erp_cleanup(erp, DASD_CQR_FAILED);
        } else {
                /* fatal error -  set status to FAILED
                   internal error 09 - Command Reject */
                dev_err(&device->cdev->dev, "An error occurred in the DASD "
                        "device driver, reason=%s\n", "09");

                erp = dasd_3990_erp_cleanup(erp, DASD_CQR_FAILED);
        }

        return erp;

}                               /* end dasd_3990_erp_com_rej */

/*
 * DASD_3990_ERP_BUS_OUT
 *
 * DESCRIPTION
 *   Handles 24 byte 'Bus Out Parity Check' error.
 *
 * PARAMETER
 *   erp                current erp_head
 * RETURN VALUES
 *   erp                new erp_head - pointer to new ERP
 */
static struct dasd_ccw_req *
dasd_3990_erp_bus_out(struct dasd_ccw_req * erp)
{

        struct dasd_device *device = erp->startdev;

        /* first time set initial retry counter and erp_function */
        /* and retry once without blocking queue                 */
        /* (this enables easier enqueing of the cqr)             */
        if (erp->function != dasd_3990_erp_bus_out) {
                erp->retries = 256;
                erp->function = dasd_3990_erp_bus_out;

        } else {

                /* issue a message and wait for 'device ready' interrupt */
                DBF_DEV_EVENT(DBF_WARNING, device, "%s",
                            "bus out parity error or BOPC requested by "
                            "channel");

                dasd_3990_erp_block_queue(erp, 60*HZ);

        }

        return erp;

}                               /* end dasd_3990_erp_bus_out */

/*
 * DASD_3990_ERP_EQUIP_CHECK
 *
 * DESCRIPTION
 *   Handles 24 byte 'Equipment Check' error.
 *
 * PARAMETER
 *   erp                current erp_head
 * RETURN VALUES
 *   erp                new erp_head - pointer to new ERP
 */
static struct dasd_ccw_req *
dasd_3990_erp_equip_check(struct dasd_ccw_req * erp, char *sense)
{

        struct dasd_device *device = erp->startdev;

        erp->function = dasd_3990_erp_equip_check;

        if (sense[1] & SNS1_WRITE_INHIBITED) {
                dev_info(&device->cdev->dev,
                            "Write inhibited path encountered\n");

                /* vary path offline
                   internal error 04 - Path should be varied off-line.*/
                dev_err(&device->cdev->dev, "An error occurred in the DASD "
                        "device driver, reason=%s\n", "04");

                erp = dasd_3990_erp_action_1(erp);

        } else if (sense[2] & SNS2_ENV_DATA_PRESENT) {

                DBF_DEV_EVENT(DBF_WARNING, device, "%s",
                            "Equipment Check - " "environmental data present");

                dasd_3990_handle_env_data(erp, sense);

                erp = dasd_3990_erp_action_4(erp, sense);

        } else if (sense[1] & SNS1_PERM_ERR) {

                DBF_DEV_EVENT(DBF_WARNING, device, "%s",
                            "Equipment Check - retry exhausted or "
                            "undesirable");

                erp = dasd_3990_erp_action_1(erp);

        } else {
                /* all other equipment checks - Action 5 */
                /* rest is done when retries == 0 */
                DBF_DEV_EVENT(DBF_WARNING, device, "%s",
                            "Equipment check or processing error");

                erp = dasd_3990_erp_action_5(erp);
        }
        return erp;

}                               /* end dasd_3990_erp_equip_check */

/*
 * DASD_3990_ERP_DATA_CHECK
 *
 * DESCRIPTION
 *   Handles 24 byte 'Data Check' error.
 *
 * PARAMETER
 *   erp                current erp_head
 * RETURN VALUES
 *   erp                new erp_head - pointer to new ERP
 */
static struct dasd_ccw_req *
dasd_3990_erp_data_check(struct dasd_ccw_req * erp, char *sense)
{

        struct dasd_device *device = erp->startdev;

        erp->function = dasd_3990_erp_data_check;

        if (sense[2] & SNS2_CORRECTABLE) {      /* correctable data check */

                /* issue message that the data has been corrected */
                dev_emerg(&device->cdev->dev,
                            "Data recovered during retry with PCI "
                            "fetch mode active\n");

                /* not possible to handle this situation in Linux */
                panic("No way to inform application about the possibly "
                      "incorrect data");

        } else if (sense[2] & SNS2_ENV_DATA_PRESENT) {

                DBF_DEV_EVENT(DBF_WARNING, device, "%s",
                            "Uncorrectable data check recovered secondary "
                            "addr of duplex pair");

                erp = dasd_3990_erp_action_4(erp, sense);

        } else if (sense[1] & SNS1_PERM_ERR) {

                DBF_DEV_EVENT(DBF_WARNING, device, "%s",
                            "Uncorrectable data check with internal "
                            "retry exhausted");

                erp = dasd_3990_erp_action_1(erp);

        } else {
                /* all other data checks */
                DBF_DEV_EVENT(DBF_WARNING, device, "%s",
                            "Uncorrectable data check with retry count "
                            "exhausted...");

                erp = dasd_3990_erp_action_5(erp);
        }

        return erp;

}                               /* end dasd_3990_erp_data_check */

/*
 * DASD_3990_ERP_OVERRUN
 *
 * DESCRIPTION
 *   Handles 24 byte 'Overrun' error.
 *
 * PARAMETER
 *   erp                current erp_head
 * RETURN VALUES
 *   erp                new erp_head - pointer to new ERP
 */
static struct dasd_ccw_req *
dasd_3990_erp_overrun(struct dasd_ccw_req * erp, char *sense)
{

        struct dasd_device *device = erp->startdev;

        erp->function = dasd_3990_erp_overrun;

        DBF_DEV_EVENT(DBF_WARNING, device, "%s",
                    "Overrun - service overrun or overrun"
                    " error requested by channel");

        erp = dasd_3990_erp_action_5(erp);

        return erp;

}                               /* end dasd_3990_erp_overrun */

/*
 * DASD_3990_ERP_INV_FORMAT
 *
 * DESCRIPTION
 *   Handles 24 byte 'Invalid Track Format' error.
 *
 * PARAMETER
 *   erp                current erp_head
 * RETURN VALUES
 *   erp                new erp_head - pointer to new ERP
 */
static struct dasd_ccw_req *
dasd_3990_erp_inv_format(struct dasd_ccw_req * erp, char *sense)
{

        struct dasd_device *device = erp->startdev;

        erp->function = dasd_3990_erp_inv_format;

        if (sense[2] & SNS2_ENV_DATA_PRESENT) {

                DBF_DEV_EVENT(DBF_WARNING, device, "%s",
                            "Track format error when destaging or "
                            "staging data");

                dasd_3990_handle_env_data(erp, sense);

                erp = dasd_3990_erp_action_4(erp, sense);

        } else {
                /* internal error 06 - The track format is not valid*/
                dev_err(&device->cdev->dev,
                        "An error occurred in the DASD device driver, "
                        "reason=%s\n", "06");

                erp = dasd_3990_erp_cleanup(erp, DASD_CQR_FAILED);
        }

        return erp;

}                               /* end dasd_3990_erp_inv_format */

/*
 * DASD_3990_ERP_EOC
 *
 * DESCRIPTION
 *   Handles 24 byte 'End-of-Cylinder' error.
 *
 * PARAMETER
 *   erp                already added default erp
 * RETURN VALUES
 *   erp                pointer to original (failed) cqr.
 */
static struct dasd_ccw_req *
dasd_3990_erp_EOC(struct dasd_ccw_req * default_erp, char *sense)
{

        struct dasd_device *device = default_erp->startdev;

        dev_err(&device->cdev->dev,
                "The cylinder data for accessing the DASD is inconsistent\n");

        /* implement action 7 - BUG */
        return dasd_3990_erp_cleanup(default_erp, DASD_CQR_FAILED);

}                               /* end dasd_3990_erp_EOC */

/*
 * DASD_3990_ERP_ENV_DATA
 *
 * DESCRIPTION
 *   Handles 24 byte 'Environmental-Data Present' error.
 *
 * PARAMETER
 *   erp                current erp_head
 * RETURN VALUES
 *   erp                new erp_head - pointer to new ERP
 */
static struct dasd_ccw_req *
dasd_3990_erp_env_data(struct dasd_ccw_req * erp, char *sense)
{

        struct dasd_device *device = erp->startdev;

        erp->function = dasd_3990_erp_env_data;

        DBF_DEV_EVENT(DBF_WARNING, device, "%s", "Environmental data present");

        dasd_3990_handle_env_data(erp, sense);

        /* don't retry on disabled interface */
        if (sense[7] != 0x0F) {
                erp = dasd_3990_erp_action_4(erp, sense);
        } else {
                erp->status = DASD_CQR_FILLED;
        }

        return erp;

}                               /* end dasd_3990_erp_env_data */

/*
 * DASD_3990_ERP_NO_REC
 *
 * DESCRIPTION
 *   Handles 24 byte 'No Record Found' error.
 *
 * PARAMETER
 *   erp                already added default ERP
 *
 * RETURN VALUES
 *   erp                new erp_head - pointer to new ERP
 */
static struct dasd_ccw_req *
dasd_3990_erp_no_rec(struct dasd_ccw_req * default_erp, char *sense)
{

        struct dasd_device *device = default_erp->startdev;

        dev_err(&device->cdev->dev,
                    "The specified record was not found\n");

        return dasd_3990_erp_cleanup(default_erp, DASD_CQR_FAILED);

}                               /* end dasd_3990_erp_no_rec */

/*
 * DASD_3990_ERP_FILE_PROT
 *
 * DESCRIPTION
 *   Handles 24 byte 'File Protected' error.
 *   Note: Seek related recovery is not implemented because
 *         wee don't use the seek command yet.
 *
 * PARAMETER
 *   erp                current erp_head
 * RETURN VALUES
 *   erp                new erp_head - pointer to new ERP
 */
static struct dasd_ccw_req *
dasd_3990_erp_file_prot(struct dasd_ccw_req * erp)
{

        struct dasd_device *device = erp->startdev;

        dev_err(&device->cdev->dev, "Accessing the DASD failed because of "
                "a hardware error\n");

        return dasd_3990_erp_cleanup(erp, DASD_CQR_FAILED);

}                               /* end dasd_3990_erp_file_prot */

/*
 * DASD_3990_ERP_INSPECT_ALIAS
 *
 * DESCRIPTION
 *   Checks if the original request was started on an alias device.
 *   If yes, it modifies the original and the erp request so that
 *   the erp request can be started on a base device.
 *
 * PARAMETER
 *   erp                pointer to the currently created default ERP
 *
 * RETURN VALUES
 *   erp                pointer to the modified ERP, or NULL
 */

static struct dasd_ccw_req *dasd_3990_erp_inspect_alias(
                                                struct dasd_ccw_req *erp)
{
        struct dasd_ccw_req *cqr = erp->refers;
        char *sense;

        if (cqr->block &&
            (cqr->block->base != cqr->startdev)) {

                sense = dasd_get_sense(&erp->refers->irb);
                /*
                 * dynamic pav may have changed base alias mapping
                 */
                if (!test_bit(DASD_FLAG_OFFLINE, &cqr->startdev->flags) && sense
                    && (sense[0] == 0x10) && (sense[7] == 0x0F)
                    && (sense[8] == 0x67)) {
                        /*
                         * remove device from alias handling to prevent new
                         * requests from being scheduled on the
                         * wrong alias device
                         */
                        dasd_alias_remove_device(cqr->startdev);

                        /* schedule worker to reload device */
                        dasd_reload_device(cqr->startdev);
                }

                if (cqr->startdev->features & DASD_FEATURE_ERPLOG) {
                        DBF_DEV_EVENT(DBF_ERR, cqr->startdev,
                                    "ERP on alias device for request %p,"
                                    " recover on base device %s", cqr,
                                    dev_name(&cqr->block->base->cdev->dev));
                }
                dasd_eckd_reset_ccw_to_base_io(cqr);
                erp->startdev = cqr->block->base;
                erp->function = dasd_3990_erp_inspect_alias;
                return erp;
        } else
                return NULL;
}


/*
 * DASD_3990_ERP_INSPECT_24
 *
 * DESCRIPTION
 *   Does a detailed inspection of the 24 byte sense data
 *   and sets up a related error recovery action.
 *
 * PARAMETER
 *   sense              sense data of the actual error
 *   erp                pointer to the currently created default ERP
 *
 * RETURN VALUES
 *   erp                pointer to the (addtitional) ERP
 */
static struct dasd_ccw_req *
dasd_3990_erp_inspect_24(struct dasd_ccw_req * erp, char *sense)
{

        struct dasd_ccw_req *erp_filled = NULL;

        /* Check sense for ....    */
        /* 'Command Reject'        */
        if ((erp_filled == NULL) && (sense[0] & SNS0_CMD_REJECT)) {
                erp_filled = dasd_3990_erp_com_rej(erp, sense);
        }
        /* 'Intervention Required' */
        if ((erp_filled == NULL) && (sense[0] & SNS0_INTERVENTION_REQ)) {
                erp_filled = dasd_3990_erp_int_req(erp);
        }
        /* 'Bus Out Parity Check'  */
        if ((erp_filled == NULL) && (sense[0] & SNS0_BUS_OUT_CHECK)) {
                erp_filled = dasd_3990_erp_bus_out(erp);
        }
        /* 'Equipment Check'       */
        if ((erp_filled == NULL) && (sense[0] & SNS0_EQUIPMENT_CHECK)) {
                erp_filled = dasd_3990_erp_equip_check(erp, sense);
        }
        /* 'Data Check'            */
        if ((erp_filled == NULL) && (sense[0] & SNS0_DATA_CHECK)) {
                erp_filled = dasd_3990_erp_data_check(erp, sense);
        }
        /* 'Overrun'               */
        if ((erp_filled == NULL) && (sense[0] & SNS0_OVERRUN)) {
                erp_filled = dasd_3990_erp_overrun(erp, sense);
        }
        /* 'Invalid Track Format'  */
        if ((erp_filled == NULL) && (sense[1] & SNS1_INV_TRACK_FORMAT)) {
                erp_filled = dasd_3990_erp_inv_format(erp, sense);
        }
        /* 'End-of-Cylinder'       */
        if ((erp_filled == NULL) && (sense[1] & SNS1_EOC)) {
                erp_filled = dasd_3990_erp_EOC(erp, sense);
        }
        /* 'Environmental Data'    */
        if ((erp_filled == NULL) && (sense[2] & SNS2_ENV_DATA_PRESENT)) {
                erp_filled = dasd_3990_erp_env_data(erp, sense);
        }
        /* 'No Record Found'       */
        if ((erp_filled == NULL) && (sense[1] & SNS1_NO_REC_FOUND)) {
                erp_filled = dasd_3990_erp_no_rec(erp, sense);
        }
        /* 'File Protected'        */
        if ((erp_filled == NULL) && (sense[1] & SNS1_FILE_PROTECTED)) {
                erp_filled = dasd_3990_erp_file_prot(erp);
        }
        /* other (unknown) error - do default ERP */
        if (erp_filled == NULL) {

                erp_filled = erp;
        }

        return erp_filled;

}                               /* END dasd_3990_erp_inspect_24 */

/*
 *****************************************************************************
 * 32 byte sense ERP functions (only)
 *****************************************************************************
 */

/*
 * DASD_3990_ERPACTION_10_32
 *
 * DESCRIPTION
 *   Handles 32 byte 'Action 10' of Single Program Action Codes.
 *   Just retry and if retry doesn't work, return with error.
 *
 * PARAMETER
 *   erp                current erp_head
 *   sense              current sense data
 * RETURN VALUES
 *   erp                modified erp_head
 */
static struct dasd_ccw_req *
dasd_3990_erp_action_10_32(struct dasd_ccw_req * erp, char *sense)
{

        struct dasd_device *device = erp->startdev;

        erp->retries = 256;
        erp->function = dasd_3990_erp_action_10_32;

        DBF_DEV_EVENT(DBF_WARNING, device, "%s", "Perform logging requested");

        return erp;

}                               /* end dasd_3990_erp_action_10_32 */

/*
 * DASD_3990_ERP_ACTION_1B_32
 *
 * DESCRIPTION
 *   Handles 32 byte 'Action 1B' of Single Program Action Codes.
 *   A write operation could not be finished because of an unexpected
 *   condition.
 *   The already created 'default erp' is used to get the link to
 *   the erp chain, but it can not be used for this recovery
 *   action because it contains no DE/LO data space.
 *
 * PARAMETER
 *   default_erp        already added default erp.
 *   sense              current sense data
 *
 * RETURN VALUES
 *   erp                new erp or
 *                      default_erp in case of imprecise ending or error
 */
static struct dasd_ccw_req *
dasd_3990_erp_action_1B_32(struct dasd_ccw_req * default_erp, char *sense)
{

        struct dasd_device *device = default_erp->startdev;
        __u32 cpa = 0;
        struct dasd_ccw_req *cqr;
        struct dasd_ccw_req *erp;
        struct DE_eckd_data *DE_data;
        struct PFX_eckd_data *PFX_data;
        char *LO_data;          /* LO_eckd_data_t */
        struct ccw1 *ccw, *oldccw;

        DBF_DEV_EVENT(DBF_WARNING, device, "%s",
                    "Write not finished because of unexpected condition");

        default_erp->function = dasd_3990_erp_action_1B_32;

        /* determine the original cqr */
        cqr = default_erp;

        while (cqr->refers != NULL) {
                cqr = cqr->refers;
        }

        if (scsw_is_tm(&cqr->irb.scsw)) {
                DBF_DEV_EVENT(DBF_WARNING, device, "%s",
                              "32 bit sense, action 1B is not defined"
                              " in transport mode - just retry");
                return default_erp;
        }

        /* for imprecise ending just do default erp */
        if (sense[1] & 0x01) {
                DBF_DEV_EVENT(DBF_WARNING, device, "%s",
                            "Imprecise ending is set - just retry");

                return default_erp;
        }

        /* determine the address of the CCW to be restarted */
        /* Imprecise ending is not set -> addr from IRB-SCSW */
        cpa = default_erp->refers->irb.scsw.cmd.cpa;

        if (cpa == 0) {
                DBF_DEV_EVENT(DBF_WARNING, device, "%s",
                            "Unable to determine address of the CCW "
                            "to be restarted");

                return dasd_3990_erp_cleanup(default_erp, DASD_CQR_FAILED);
        }

        /* Build new ERP request including DE/LO */
        erp = dasd_alloc_erp_request((char *) &cqr->magic,
                                     2 + 1,/* DE/LO + TIC */
                                     sizeof(struct DE_eckd_data) +
                                     sizeof(struct LO_eckd_data), device);

        if (IS_ERR(erp)) {
                /* internal error 01 - Unable to allocate ERP */
                dev_err(&device->cdev->dev, "An error occurred in the DASD "
                        "device driver, reason=%s\n", "01");
                return dasd_3990_erp_cleanup(default_erp, DASD_CQR_FAILED);
        }

        /* use original DE */
        DE_data = erp->data;
        oldccw = cqr->cpaddr;
        if (oldccw->cmd_code == DASD_ECKD_CCW_PFX) {
                PFX_data = cqr->data;
                memcpy(DE_data, &PFX_data->define_extent,
                       sizeof(struct DE_eckd_data));
        } else
                memcpy(DE_data, cqr->data, sizeof(struct DE_eckd_data));

        /* create LO */
        LO_data = erp->data + sizeof(struct DE_eckd_data);

        if ((sense[3] == 0x01) && (LO_data[1] & 0x01)) {
                /* should not */
                return dasd_3990_erp_cleanup(default_erp, DASD_CQR_FAILED);
        }

        if ((sense[7] & 0x3F) == 0x01) {
                /* operation code is WRITE DATA -> data area orientation */
                LO_data[0] = 0x81;

        } else if ((sense[7] & 0x3F) == 0x03) {
                /* operation code is FORMAT WRITE -> index orientation */
                LO_data[0] = 0xC3;

        } else {
                LO_data[0] = sense[7];  /* operation */
        }

        LO_data[1] = sense[8];  /* auxiliary */
        LO_data[2] = sense[9];
        LO_data[3] = sense[3];  /* count */
        LO_data[4] = sense[29]; /* seek_addr.cyl */
        LO_data[5] = sense[30]; /* seek_addr.cyl 2nd byte */
        LO_data[7] = sense[31]; /* seek_addr.head 2nd byte */

        memcpy(&(LO_data[8]), &(sense[11]), 8);

        /* create DE ccw */
        ccw = erp->cpaddr;
        memset(ccw, 0, sizeof(struct ccw1));
        ccw->cmd_code = DASD_ECKD_CCW_DEFINE_EXTENT;
        ccw->flags = CCW_FLAG_CC;
        ccw->count = 16;
        ccw->cda = (__u32)(addr_t) DE_data;

        /* create LO ccw */
        ccw++;
        memset(ccw, 0, sizeof(struct ccw1));
        ccw->cmd_code = DASD_ECKD_CCW_LOCATE_RECORD;
        ccw->flags = CCW_FLAG_CC;
        ccw->count = 16;
        ccw->cda = (__u32)(addr_t) LO_data;

        /* TIC to the failed ccw */
        ccw++;
        ccw->cmd_code = CCW_CMD_TIC;
        ccw->cda = cpa;

        /* fill erp related fields */
        erp->flags = default_erp->flags;
        erp->function = dasd_3990_erp_action_1B_32;
        erp->refers = default_erp->refers;
        erp->startdev = device;
        erp->memdev = device;
        erp->magic = default_erp->magic;
        erp->expires = 0;
        erp->retries = 256;
        erp->buildclk = get_clock();
        erp->status = DASD_CQR_FILLED;

        /* remove the default erp */
        dasd_free_erp_request(default_erp, device);

        return erp;

}                               /* end dasd_3990_erp_action_1B_32 */

/*
 * DASD_3990_UPDATE_1B
 *
 * DESCRIPTION
 *   Handles the update to the 32 byte 'Action 1B' of Single Program
 *   Action Codes in case the first action was not successful.
 *   The already created 'previous_erp' is the currently not successful
 *   ERP.
 *
 * PARAMETER
 *   previous_erp       already created previous erp.
 *   sense              current sense data
 * RETURN VALUES
 *   erp                modified erp
 */
static struct dasd_ccw_req *
dasd_3990_update_1B(struct dasd_ccw_req * previous_erp, char *sense)
{

        struct dasd_device *device = previous_erp->startdev;
        __u32 cpa = 0;
        struct dasd_ccw_req *cqr;
        struct dasd_ccw_req *erp;
        char *LO_data;          /* struct LO_eckd_data */
        struct ccw1 *ccw;

        DBF_DEV_EVENT(DBF_WARNING, device, "%s",
                    "Write not finished because of unexpected condition"
                    " - follow on");

        /* determine the original cqr */
        cqr = previous_erp;

        while (cqr->refers != NULL) {
                cqr = cqr->refers;
        }

        if (scsw_is_tm(&cqr->irb.scsw)) {
                DBF_DEV_EVENT(DBF_WARNING, device, "%s",
                              "32 bit sense, action 1B, update,"
                              " in transport mode - just retry");
                return previous_erp;
        }

        /* for imprecise ending just do default erp */
        if (sense[1] & 0x01) {
                DBF_DEV_EVENT(DBF_WARNING, device, "%s",
                            "Imprecise ending is set - just retry");

                previous_erp->status = DASD_CQR_FILLED;

                return previous_erp;
        }

        /* determine the address of the CCW to be restarted */
        /* Imprecise ending is not set -> addr from IRB-SCSW */
        cpa = previous_erp->irb.scsw.cmd.cpa;

        if (cpa == 0) {
                /* internal error 02 -
                   Unable to determine address of the CCW to be restarted */
                dev_err(&device->cdev->dev, "An error occurred in the DASD "
                        "device driver, reason=%s\n", "02");

                previous_erp->status = DASD_CQR_FAILED;

                return previous_erp;
        }

        erp = previous_erp;

        /* update the LO with the new returned sense data  */
        LO_data = erp->data + sizeof(struct DE_eckd_data);

        if ((sense[3] == 0x01) && (LO_data[1] & 0x01)) {
                /* should not happen */
                previous_erp->status = DASD_CQR_FAILED;

                return previous_erp;
        }

        if ((sense[7] & 0x3F) == 0x01) {
                /* operation code is WRITE DATA -> data area orientation */
                LO_data[0] = 0x81;

        } else if ((sense[7] & 0x3F) == 0x03) {
                /* operation code is FORMAT WRITE -> index orientation */
                LO_data[0] = 0xC3;

        } else {
                LO_data[0] = sense[7];  /* operation */
        }

        LO_data[1] = sense[8];  /* auxiliary */
        LO_data[2] = sense[9];
        LO_data[3] = sense[3];  /* count */
        LO_data[4] = sense[29]; /* seek_addr.cyl */
        LO_data[5] = sense[30]; /* seek_addr.cyl 2nd byte */
        LO_data[7] = sense[31]; /* seek_addr.head 2nd byte */

        memcpy(&(LO_data[8]), &(sense[11]), 8);

        /* TIC to the failed ccw */
        ccw = erp->cpaddr;      /* addr of DE ccw */
        ccw++;                  /* addr of LE ccw */
        ccw++;                  /* addr of TIC ccw */
        ccw->cda = cpa;

        erp->status = DASD_CQR_FILLED;

        return erp;

}                               /* end dasd_3990_update_1B */

/*
 * DASD_3990_ERP_COMPOUND_RETRY
 *
 * DESCRIPTION
 *   Handles the compound ERP action retry code.
 *   NOTE: At least one retry is done even if zero is specified
 *         by the sense data. This makes enqueueing of the request
 *         easier.
 *
 * PARAMETER
 *   sense              sense data of the actual error
 *   erp                pointer to the currently created ERP
 *
 * RETURN VALUES
 *   erp                modified ERP pointer
 *
 */
static void
dasd_3990_erp_compound_retry(struct dasd_ccw_req * erp, char *sense)
{

        switch (sense[25] & 0x03) {
        case 0x00:              /* no not retry */
                erp->retries = 1;
                break;

        case 0x01:              /* retry 2 times */
                erp->retries = 2;
                break;

        case 0x02:              /* retry 10 times */
                erp->retries = 10;
                break;

        case 0x03:              /* retry 256 times */
                erp->retries = 256;
                break;

        default:
                BUG();
        }

        erp->function = dasd_3990_erp_compound_retry;

}                               /* end dasd_3990_erp_compound_retry */

/*
 * DASD_3990_ERP_COMPOUND_PATH
 *
 * DESCRIPTION
 *   Handles the compound ERP action for retry on alternate
 *   channel path.
 *
 * PARAMETER
 *   sense              sense data of the actual error
 *   erp                pointer to the currently created ERP
 *
 * RETURN VALUES
 *   erp                modified ERP pointer
 *
 */
static void
dasd_3990_erp_compound_path(struct dasd_ccw_req * erp, char *sense)
{
        if (sense[25] & DASD_SENSE_BIT_3) {
                dasd_3990_erp_alternate_path(erp);

                if (erp->status == DASD_CQR_FAILED &&
                    !test_bit(DASD_CQR_VERIFY_PATH, &erp->flags)) {
                        /* reset the lpm and the status to be able to
                         * try further actions. */
                        erp->lpm = erp->startdev->path_data.opm;
                        erp->status = DASD_CQR_NEED_ERP;
                }
        }

        erp->function = dasd_3990_erp_compound_path;

}                               /* end dasd_3990_erp_compound_path */

/*
 * DASD_3990_ERP_COMPOUND_CODE
 *
 * DESCRIPTION
 *   Handles the compound ERP action for retry code.
 *
 * PARAMETER
 *   sense              sense data of the actual error
 *   erp                pointer to the currently created ERP
 *
 * RETURN VALUES
 *   erp                NEW ERP pointer
 *
 */
static struct dasd_ccw_req *
dasd_3990_erp_compound_code(struct dasd_ccw_req * erp, char *sense)
{

        if (sense[25] & DASD_SENSE_BIT_2) {

                switch (sense[28]) {
                case 0x17:
                        /* issue a Diagnostic Control command with an
                         * Inhibit Write subcommand and controller modifier */
                        erp = dasd_3990_erp_DCTL(erp, 0x20);
                        break;

                case 0x25:
                        /* wait for 5 seconds and retry again */
                        erp->retries = 1;

                        dasd_3990_erp_block_queue (erp, 5*HZ);
                        break;

                default:
                        /* should not happen - continue */
                        break;
                }
        }

        erp->function = dasd_3990_erp_compound_code;

        return erp;

}                               /* end dasd_3990_erp_compound_code */

/*
 * DASD_3990_ERP_COMPOUND_CONFIG
 *
 * DESCRIPTION
 *   Handles the compound ERP action for configruation
 *   dependent error.
 *   Note: duplex handling is not implemented (yet).
 *
 * PARAMETER
 *   sense              sense data of the actual error
 *   erp                pointer to the currently created ERP
 *
 * RETURN VALUES
 *   erp                modified ERP pointer
 *
 */
static void
dasd_3990_erp_compound_config(struct dasd_ccw_req * erp, char *sense)
{

        if ((sense[25] & DASD_SENSE_BIT_1) && (sense[26] & DASD_SENSE_BIT_2)) {

                /* set to suspended duplex state then restart
                   internal error 05 - Set device to suspended duplex state
                   should be done */
                struct dasd_device *device = erp->startdev;
                dev_err(&device->cdev->dev,
                        "An error occurred in the DASD device driver, "

                        "reason=%s\n", "05");

        }

        erp->function = dasd_3990_erp_compound_config;

}                               /* end dasd_3990_erp_compound_config */

/*
 * DASD_3990_ERP_COMPOUND
 *
 * DESCRIPTION
 *   Does the further compound program action if
 *   compound retry was not successful.
 *
 * PARAMETER
 *   sense              sense data of the actual error
 *   erp                pointer to the current (failed) ERP
 *
 * RETURN VALUES
 *   erp                (additional) ERP pointer
 *
 */
static struct dasd_ccw_req *
dasd_3990_erp_compound(struct dasd_ccw_req * erp, char *sense)
{

        if ((erp->function == dasd_3990_erp_compound_retry) &&
            (erp->status == DASD_CQR_NEED_ERP)) {

                dasd_3990_erp_compound_path(erp, sense);
        }

        if ((erp->function == dasd_3990_erp_compound_path) &&
            (erp->status == DASD_CQR_NEED_ERP)) {

                erp = dasd_3990_erp_compound_code(erp, sense);
        }

        if ((erp->function == dasd_3990_erp_compound_code) &&
            (erp->status == DASD_CQR_NEED_ERP)) {

                dasd_3990_erp_compound_config(erp, sense);
        }

        /* if no compound action ERP specified, the request failed */
        if (erp->status == DASD_CQR_NEED_ERP)
                erp->status = DASD_CQR_FAILED;

        return erp;

}                               /* end dasd_3990_erp_compound */

/*
 *DASD_3990_ERP_HANDLE_SIM
 *
 *DESCRIPTION
 *  inspects the SIM SENSE data and starts an appropriate action
 *
 * PARAMETER
 *   sense         sense data of the actual error
 *
 * RETURN VALUES
 *   none
 */
void
dasd_3990_erp_handle_sim(struct dasd_device *device, char *sense)
{
        /* print message according to log or message to operator mode */
        if ((sense[24] & DASD_SIM_MSG_TO_OP) || (sense[1] & 0x10)) {
                /* print SIM SRC from RefCode */
                dev_err(&device->cdev->dev, "SIM - SRC: "
                            "%02x%02x%02x%02x\n", sense[22],
                            sense[23], sense[11], sense[12]);
        } else if (sense[24] & DASD_SIM_LOG) {
                /* print SIM SRC Refcode */
                dev_warn(&device->cdev->dev, "log SIM - SRC: "
                            "%02x%02x%02x%02x\n", sense[22],
                            sense[23], sense[11], sense[12]);
        }
}

/*
 * DASD_3990_ERP_INSPECT_32
 *
 * DESCRIPTION
 *   Does a detailed inspection of the 32 byte sense data
 *   and sets up a related error recovery action.
 *
 * PARAMETER
 *   sense              sense data of the actual error
 *   erp                pointer to the currently created default ERP
 *
 * RETURN VALUES
 *   erp_filled         pointer to the ERP
 *
 */
static struct dasd_ccw_req *
dasd_3990_erp_inspect_32(struct dasd_ccw_req * erp, char *sense)
{

        struct dasd_device *device = erp->startdev;

        erp->function = dasd_3990_erp_inspect_32;

        /* check for SIM sense data */
        if ((sense[6] & DASD_SIM_SENSE) == DASD_SIM_SENSE)
                dasd_3990_erp_handle_sim(device, sense);

        if (sense[25] & DASD_SENSE_BIT_0) {

                /* compound program action codes (byte25 bit 0 == '1') */
                dasd_3990_erp_compound_retry(erp, sense);

        } else {

                /* single program action codes (byte25 bit 0 == '0') */
                switch (sense[25]) {

                case 0x00:      /* success - use default ERP for retries */
                        DBF_DEV_EVENT(DBF_DEBUG, device, "%s",
                                    "ERP called for successful request"
                                    " - just retry");
                        break;

                case 0x01:      /* fatal error */
                        dev_err(&device->cdev->dev,
                                    "ERP failed for the DASD\n");

                        erp = dasd_3990_erp_cleanup(erp, DASD_CQR_FAILED);
                        break;

                case 0x02:      /* intervention required */
                case 0x03:      /* intervention required during dual copy */
                        erp = dasd_3990_erp_int_req(erp);
                        break;

                case 0x0F:  /* length mismatch during update write command
                               internal error 08 - update write command error*/
                        dev_err(&device->cdev->dev, "An error occurred in the "
                                "DASD device driver, reason=%s\n", "08");

                        erp = dasd_3990_erp_cleanup(erp, DASD_CQR_FAILED);
                        break;

                case 0x10:  /* logging required for other channel program */
                        erp = dasd_3990_erp_action_10_32(erp, sense);
                        break;

                case 0x15:      /* next track outside defined extend
                                   internal error 07 - The next track is not
                                   within the defined storage extent */
                        dev_err(&device->cdev->dev,
                                "An error occurred in the DASD device driver, "
                                "reason=%s\n", "07");

                        erp = dasd_3990_erp_cleanup(erp, DASD_CQR_FAILED);
                        break;

                case 0x1B:      /* unexpected condition during write */

                        erp = dasd_3990_erp_action_1B_32(erp, sense);
                        break;

                case 0x1C:      /* invalid data */
                        dev_emerg(&device->cdev->dev,
                                    "Data recovered during retry with PCI "
                                    "fetch mode active\n");

                        /* not possible to handle this situation in Linux */
                        panic
                            ("Invalid data - No way to inform application "
                             "about the possibly incorrect data");
                        break;

                case 0x1D:      /* state-change pending */
                        DBF_DEV_EVENT(DBF_WARNING, device, "%s",
                                    "A State change pending condition exists "
                                    "for the subsystem or device");

                        erp = dasd_3990_erp_action_4(erp, sense);
                        break;

                case 0x1E:      /* busy */
                        DBF_DEV_EVENT(DBF_WARNING, device, "%s",
                                    "Busy condition exists "
                                    "for the subsystem or device");
                        erp = dasd_3990_erp_action_4(erp, sense);
                        break;

                default:        /* all others errors - default erp  */
                        break;
                }
        }

        return erp;

}                               /* end dasd_3990_erp_inspect_32 */

/*
 *****************************************************************************
 * main ERP control functions (24 and 32 byte sense)
 *****************************************************************************
 */

/*
 * DASD_3990_ERP_CONTROL_CHECK
 *
 * DESCRIPTION
 *   Does a generic inspection if a control check occurred and sets up
 *   the related error recovery procedure
 *
 * PARAMETER
 *   erp                pointer to the currently created default ERP
 *
 * RETURN VALUES
 *   erp_filled         pointer to the erp
 */

static struct dasd_ccw_req *
dasd_3990_erp_control_check(struct dasd_ccw_req *erp)
{
        struct dasd_device *device = erp->startdev;

        if (scsw_cstat(&erp->refers->irb.scsw) & (SCHN_STAT_INTF_CTRL_CHK
                                           | SCHN_STAT_CHN_CTRL_CHK)) {
                DBF_DEV_EVENT(DBF_WARNING, device, "%s",
                            "channel or interface control check");
                erp = dasd_3990_erp_action_4(erp, NULL);
        }
        return erp;
}

/*
 * DASD_3990_ERP_INSPECT
 *
 * DESCRIPTION
 *   Does a detailed inspection for sense data by calling either
 *   the 24-byte or the 32-byte inspection routine.
 *
 * PARAMETER
 *   erp                pointer to the currently created default ERP
 * RETURN VALUES
 *   erp_new            contens was possibly modified
 */
static struct dasd_ccw_req *
dasd_3990_erp_inspect(struct dasd_ccw_req *erp)
{

        struct dasd_ccw_req *erp_new = NULL;
        char *sense;

        /* if this problem occurred on an alias retry on base */
        erp_new = dasd_3990_erp_inspect_alias(erp);
        if (erp_new)
                return erp_new;

        /* sense data are located in the refers record of the
         * already set up new ERP !
         * check if concurrent sens is available
         */
        sense = dasd_get_sense(&erp->refers->irb);
        if (!sense)
                erp_new = dasd_3990_erp_control_check(erp);
        /* distinguish between 24 and 32 byte sense data */
        else if (sense[27] & DASD_SENSE_BIT_0) {

                /* inspect the 24 byte sense data */
                erp_new = dasd_3990_erp_inspect_24(erp, sense);

        } else {

                /* inspect the 32 byte sense data */
                erp_new = dasd_3990_erp_inspect_32(erp, sense);

        }       /* end distinguish between 24 and 32 byte sense data */

        return erp_new;
}

/*
 * DASD_3990_ERP_ADD_ERP
 *
 * DESCRIPTION
 *   This function adds an additional request block (ERP) to the head of
 *   the given cqr (or erp).
 *   For a command mode cqr the erp is initialized as an default erp
 *   (retry TIC).
 *   For transport mode we make a copy of the original TCW (points to
 *   the original TCCB, TIDALs, etc.) but give it a fresh
 *   TSB so the original sense data will not be changed.
 *
 * PARAMETER
 *   cqr                head of the current ERP-chain (or single cqr if
 *                      first error)
 * RETURN VALUES
 *   erp                pointer to new ERP-chain head
 */
static struct dasd_ccw_req *dasd_3990_erp_add_erp(struct dasd_ccw_req *cqr)
{

        struct dasd_device *device = cqr->startdev;
        struct ccw1 *ccw;
        struct dasd_ccw_req *erp;
        int cplength, datasize;
        struct tcw *tcw;
        struct tsb *tsb;

        if (cqr->cpmode == 1) {
                cplength = 0;
                /* TCW needs to be 64 byte aligned, so leave enough room */
                datasize = 64 + sizeof(struct tcw) + sizeof(struct tsb);
        } else {
                cplength = 2;
                datasize = 0;
        }

        /* allocate additional request block */
        erp = dasd_alloc_erp_request((char *) &cqr->magic,
                                     cplength, datasize, device);
        if (IS_ERR(erp)) {
                if (cqr->retries <= 0) {
                        DBF_DEV_EVENT(DBF_ERR, device, "%s",
                                    "Unable to allocate ERP request");
                        cqr->status = DASD_CQR_FAILED;
                        cqr->stopclk = get_clock ();
                } else {
                        DBF_DEV_EVENT(DBF_ERR, device,
                                     "Unable to allocate ERP request "
                                     "(%i retries left)",
                                     cqr->retries);
                        dasd_block_set_timer(device->block, (HZ << 3));
                }
                return erp;
        }

        ccw = cqr->cpaddr;
        if (cqr->cpmode == 1) {
                /* make a shallow copy of the original tcw but set new tsb */
                erp->cpmode = 1;
                erp->cpaddr = PTR_ALIGN(erp->data, 64);
                tcw = erp->cpaddr;
                tsb = (struct tsb *) &tcw[1];
                *tcw = *((struct tcw *)cqr->cpaddr);
                tcw->tsb = (long)tsb;
        } else if (ccw->cmd_code == DASD_ECKD_CCW_PSF) {
                /* PSF cannot be chained from NOOP/TIC */
                erp->cpaddr = cqr->cpaddr;
        } else {
                /* initialize request with default TIC to current ERP/CQR */
                ccw = erp->cpaddr;
                ccw->cmd_code = CCW_CMD_NOOP;
                ccw->flags = CCW_FLAG_CC;
                ccw++;
                ccw->cmd_code = CCW_CMD_TIC;
                ccw->cda      = (long)(cqr->cpaddr);
        }

        erp->flags = cqr->flags;
        erp->function = dasd_3990_erp_add_erp;
        erp->refers   = cqr;
        erp->startdev = device;
        erp->memdev   = device;
        erp->block    = cqr->block;
        erp->magic    = cqr->magic;
        erp->expires  = 0;
        erp->retries  = 256;
        erp->buildclk = get_clock();
        erp->status = DASD_CQR_FILLED;

        return erp;
}

/*
 * DASD_3990_ERP_ADDITIONAL_ERP
 *
 * DESCRIPTION
 *   An additional ERP is needed to handle the current error.
 *   Add ERP to the head of the ERP-chain containing the ERP processing
 *   determined based on the sense data.
 *
 * PARAMETER
 *   cqr                head of the current ERP-chain (or single cqr if
 *                      first error)
 *
 * RETURN VALUES
 *   erp                pointer to new ERP-chain head
 */
static struct dasd_ccw_req *
dasd_3990_erp_additional_erp(struct dasd_ccw_req * cqr)
{

        struct dasd_ccw_req *erp = NULL;

        /* add erp and initialize with default TIC */
        erp = dasd_3990_erp_add_erp(cqr);

        if (IS_ERR(erp))
                return erp;

        /* inspect sense, determine specific ERP if possible */
        if (erp != cqr) {

                erp = dasd_3990_erp_inspect(erp);
        }

        return erp;

}                               /* end dasd_3990_erp_additional_erp */

/*
 * DASD_3990_ERP_ERROR_MATCH
 *
 * DESCRIPTION
 *   Check if the device status of the given cqr is the same.
 *   This means that the failed CCW and the relevant sense data
 *   must match.
 *   I don't distinguish between 24 and 32 byte sense because in case of
 *   24 byte sense byte 25 and 27 is set as well.
 *
 * PARAMETER
 *   cqr1               first cqr, which will be compared with the
 *   cqr2               second cqr.
 *
 * RETURN VALUES
 *   match              'boolean' for match found
 *                      returns 1 if match found, otherwise 0.
 */
static int dasd_3990_erp_error_match(struct dasd_ccw_req *cqr1,
                                     struct dasd_ccw_req *cqr2)
{
        char *sense1, *sense2;

        if (cqr1->startdev != cqr2->startdev)
                return 0;

        sense1 = dasd_get_sense(&cqr1->irb);
        sense2 = dasd_get_sense(&cqr2->irb);

        /* one request has sense data, the other not -> no match, return 0 */
        if (!sense1 != !sense2)
                return 0;
        /* no sense data in both cases -> check cstat for IFCC */
        if (!sense1 && !sense2) {
                if ((scsw_cstat(&cqr1->irb.scsw) & (SCHN_STAT_INTF_CTRL_CHK |
                                                    SCHN_STAT_CHN_CTRL_CHK)) ==
                    (scsw_cstat(&cqr2->irb.scsw) & (SCHN_STAT_INTF_CTRL_CHK |
                                                    SCHN_STAT_CHN_CTRL_CHK)))
                        return 1; /* match with ifcc*/
        }
        /* check sense data; byte 0-2,25,27 */
        if (!(sense1 && sense2 &&
              (memcmp(sense1, sense2, 3) == 0) &&
              (sense1[27] == sense2[27]) &&
              (sense1[25] == sense2[25]))) {

                return 0;       /* sense doesn't match */
        }

        return 1;               /* match */

}                               /* end dasd_3990_erp_error_match */

/*
 * DASD_3990_ERP_IN_ERP
 *
 * DESCRIPTION
 *   check if the current error already happened before.
 *   quick exit if current cqr is not an ERP (cqr->refers=NULL)
 *
 * PARAMETER
 *   cqr                failed cqr (either original cqr or already an erp)
 *
 * RETURN VALUES
 *   erp                erp-pointer to the already defined error
 *                      recovery procedure OR
 *                      NULL if a 'new' error occurred.
 */
static struct dasd_ccw_req *
dasd_3990_erp_in_erp(struct dasd_ccw_req *cqr)
{

        struct dasd_ccw_req *erp_head = cqr,    /* save erp chain head */
        *erp_match = NULL;      /* save erp chain head */
        int match = 0;          /* 'boolean' for matching error found */

        if (cqr->refers == NULL) {      /* return if not in erp */
                return NULL;
        }

        /* check the erp/cqr chain for current error */
        do {
                match = dasd_3990_erp_error_match(erp_head, cqr->refers);
                erp_match = cqr;        /* save possible matching erp  */
                cqr = cqr->refers;      /* check next erp/cqr in queue */

        } while ((cqr->refers != NULL) && (!match));

        if (!match) {
                return NULL;    /* no match was found */
        }

        return erp_match;       /* return address of matching erp */

}                               /* END dasd_3990_erp_in_erp */

/*
 * DASD_3990_ERP_FURTHER_ERP (24 & 32 byte sense)
 *
 * DESCRIPTION
 *   No retry is left for the current ERP. Check what has to be done
 *   with the ERP.
 *     - do further defined ERP action or
 *     - wait for interrupt or
 *     - exit with permanent error
 *
 * PARAMETER
 *   erp                ERP which is in progress with no retry left
 *
 * RETURN VALUES
 *   erp                modified/additional ERP
 */
static struct dasd_ccw_req *
dasd_3990_erp_further_erp(struct dasd_ccw_req *erp)
{

        struct dasd_device *device = erp->startdev;
        char *sense = dasd_get_sense(&erp->irb);

        /* check for 24 byte sense ERP */
        if ((erp->function == dasd_3990_erp_bus_out) ||
            (erp->function == dasd_3990_erp_action_1) ||
            (erp->function == dasd_3990_erp_action_4)) {

                erp = dasd_3990_erp_action_1(erp);

        } else if (erp->function == dasd_3990_erp_action_1_sec) {
                erp = dasd_3990_erp_action_1_sec(erp);
        } else if (erp->function == dasd_3990_erp_action_5) {

                /* retries have not been successful */
                /* prepare erp for retry on different channel path */
                erp = dasd_3990_erp_action_1(erp);

                if (sense && !(sense[2] & DASD_SENSE_BIT_0)) {

                        /* issue a Diagnostic Control command with an
                         * Inhibit Write subcommand */

                        switch (sense[25]) {
                        case 0x17:
                        case 0x57:{     /* controller */
                                        erp = dasd_3990_erp_DCTL(erp, 0x20);
                                        break;
                                }
                        case 0x18:
                        case 0x58:{     /* channel path */
                                        erp = dasd_3990_erp_DCTL(erp, 0x40);
                                        break;
                                }
                        case 0x19:
                        case 0x59:{     /* storage director */
                                        erp = dasd_3990_erp_DCTL(erp, 0x80);
                                        break;
                                }
                        default:
                                DBF_DEV_EVENT(DBF_WARNING, device,
                                            "invalid subcommand modifier 0x%x "
                                            "for Diagnostic Control Command",
                                            sense[25]);
                        }
                }

                /* check for 32 byte sense ERP */
        } else if (sense &&
                   ((erp->function == dasd_3990_erp_compound_retry) ||
                    (erp->function == dasd_3990_erp_compound_path) ||
                    (erp->function == dasd_3990_erp_compound_code) ||
                    (erp->function == dasd_3990_erp_compound_config))) {

                erp = dasd_3990_erp_compound(erp, sense);

        } else {
                /*
                 * No retry left and no additional special handling
                 * necessary
                 */
                dev_err(&device->cdev->dev,
                        "ERP %p has run out of retries and failed\n", erp);

                erp->status = DASD_CQR_FAILED;
        }

        return erp;

}                               /* end dasd_3990_erp_further_erp */

/*
 * DASD_3990_ERP_HANDLE_MATCH_ERP
 *
 * DESCRIPTION
 *   An error occurred again and an ERP has been detected which is already
 *   used to handle this error (e.g. retries).
 *   All prior ERP's are asumed to be successful and therefore removed
 *   from queue.
 *   If retry counter of matching erp is already 0, it is checked if further
 *   action is needed (besides retry) or if the ERP has failed.
 *
 * PARAMETER
 *   erp_head           first ERP in ERP-chain
 *   erp                ERP that handles the actual error.
 *                      (matching erp)
 *
 * RETURN VALUES
 *   erp                modified/additional ERP
 */
static struct dasd_ccw_req *
dasd_3990_erp_handle_match_erp(struct dasd_ccw_req *erp_head,
                               struct dasd_ccw_req *erp)
{

        struct dasd_device *device = erp_head->startdev;
        struct dasd_ccw_req *erp_done = erp_head;       /* finished req */
        struct dasd_ccw_req *erp_free = NULL;   /* req to be freed */

        /* loop over successful ERPs and remove them from chanq */
        while (erp_done != erp) {

                if (erp_done == NULL)   /* end of chain reached */
                        panic(PRINTK_HEADER "Programming error in ERP! The "
                              "original request was lost\n");

                /* remove the request from the device queue */
                list_del(&erp_done->blocklist);

                erp_free = erp_done;
                erp_done = erp_done->refers;

                /* free the finished erp request */
                dasd_free_erp_request(erp_free, erp_free->memdev);

        }                       /* end while */

        if (erp->retries > 0) {

                char *sense = dasd_get_sense(&erp->refers->irb);

                /* check for special retries */
                if (sense && erp->function == dasd_3990_erp_action_4) {

                        erp = dasd_3990_erp_action_4(erp, sense);

                } else if (sense &&
                           erp->function == dasd_3990_erp_action_1B_32) {

                        erp = dasd_3990_update_1B(erp, sense);

                } else if (sense && erp->function == dasd_3990_erp_int_req) {

                        erp = dasd_3990_erp_int_req(erp);

                } else {
                        /* simple retry   */
                        DBF_DEV_EVENT(DBF_DEBUG, device,
                                    "%i retries left for erp %p",
                                    erp->retries, erp);

                        /* handle the request again... */
                        erp->status = DASD_CQR_FILLED;
                }

        } else {
                /* no retry left - check for further necessary action    */
                /* if no further actions, handle rest as permanent error */
                erp = dasd_3990_erp_further_erp(erp);
        }

        return erp;

}                               /* end dasd_3990_erp_handle_match_erp */

/*
 * DASD_3990_ERP_ACTION
 *
 * DESCRIPTION
 *   control routine for 3990 erp actions.
 *   Has to be called with the queue lock (namely the s390_irq_lock) acquired.
 *
 * PARAMETER
 *   cqr                failed cqr (either original cqr or already an erp)
 *
 * RETURN VALUES
 *   erp                erp-pointer to the head of the ERP action chain.
 *                      This means:
 *                       - either a ptr to an additional ERP cqr or
 *                       - the original given cqr (which's status might
 *                         be modified)
 */
struct dasd_ccw_req *
dasd_3990_erp_action(struct dasd_ccw_req * cqr)
{
        struct dasd_ccw_req *erp = NULL;
        struct dasd_device *device = cqr->startdev;
        struct dasd_ccw_req *temp_erp = NULL;

        if (device->features & DASD_FEATURE_ERPLOG) {
                /* print current erp_chain */
                dev_err(&device->cdev->dev,
                            "ERP chain at BEGINNING of ERP-ACTION\n");
                for (temp_erp = cqr;
                     temp_erp != NULL; temp_erp = temp_erp->refers) {

                        dev_err(&device->cdev->dev,
                                    "ERP %p (%02x) refers to %p\n",
                                    temp_erp, temp_erp->status,
                                    temp_erp->refers);
                }
        }

        /* double-check if current erp/cqr was successful */
        if ((scsw_cstat(&cqr->irb.scsw) == 0x00) &&
            (scsw_dstat(&cqr->irb.scsw) ==
             (DEV_STAT_CHN_END | DEV_STAT_DEV_END))) {

                DBF_DEV_EVENT(DBF_DEBUG, device,
                            "ERP called for successful request %p"
                            " - NO ERP necessary", cqr);

                cqr->status = DASD_CQR_DONE;

                return cqr;
        }

        /* check if error happened before */
        erp = dasd_3990_erp_in_erp(cqr);

        if (erp == NULL) {
                /* no matching erp found - set up erp */
                erp = dasd_3990_erp_additional_erp(cqr);
                if (IS_ERR(erp))
                        return erp;
        } else {
                /* matching erp found - set all leading erp's to DONE */
                erp = dasd_3990_erp_handle_match_erp(cqr, erp);
        }

        if (device->features & DASD_FEATURE_ERPLOG) {
                /* print current erp_chain */
                dev_err(&device->cdev->dev,
                            "ERP chain at END of ERP-ACTION\n");
                for (temp_erp = erp;
                     temp_erp != NULL; temp_erp = temp_erp->refers) {

                        dev_err(&device->cdev->dev,
                                    "ERP %p (%02x) refers to %p\n",
                                    temp_erp, temp_erp->status,
                                    temp_erp->refers);
                }
        }

        /* enqueue ERP request if it's a new one */
        if (list_empty(&erp->blocklist)) {
                cqr->status = DASD_CQR_IN_ERP;
                /* add erp request before the cqr */
                list_add_tail(&erp->blocklist, &cqr->blocklist);
        }



        return erp;

}                               /* end dasd_3990_erp_action */