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dasd_3990_erp.c

/*
 * 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
 *
 */

#include <linux/timer.h>
#include <linux/slab.h>
#include <asm/idals.h>
#include <asm/todclk.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 EXAMINATION
 *****************************************************************************
 */

/*
 * DASD_3990_ERP_EXAMINE_24
 *
 * DESCRIPTION
 *   Checks only for fatal (unrecoverable) error.
 *   A detailed examination of the sense data is done later outside
 *   the interrupt handler.
 *
 *   Each bit configuration leading to an action code 2 (Exit with
 *   programming error or unusual condition indication)
 *   are handled as fatal errorīs.
 *
 *   All other configurations are handled as recoverable errors.
 *
 * RETURN VALUES
 *   dasd_era_fatal     for all fatal (unrecoverable errors)
 *   dasd_era_recover   for all others.
 */
static dasd_era_t
dasd_3990_erp_examine_24(struct dasd_ccw_req * cqr, char *sense)
{

      struct dasd_device *device = cqr->device;

      /* check for 'Command Reject' */
      if ((sense[0] & SNS0_CMD_REJECT) &&
          (!(sense[2] & SNS2_ENV_DATA_PRESENT))) {

            DEV_MESSAGE(KERN_ERR, device, "%s",
                      "EXAMINE 24: Command Reject detected - "
                      "fatal error");

            return dasd_era_fatal;
      }

      /* check for 'Invalid Track Format' */
      if ((sense[1] & SNS1_INV_TRACK_FORMAT) &&
          (!(sense[2] & SNS2_ENV_DATA_PRESENT))) {

            DEV_MESSAGE(KERN_ERR, device, "%s",
                      "EXAMINE 24: Invalid Track Format detected "
                      "- fatal error");

            return dasd_era_fatal;
      }

      /* check for 'No Record Found' */
      if (sense[1] & SNS1_NO_REC_FOUND) {

                /* FIXME: fatal error ?!? */
            DEV_MESSAGE(KERN_ERR, device,
                      "EXAMINE 24: No Record Found detected %s",
                            device->state <= DASD_STATE_BASIC ?
                      " " : "- fatal error");

            return dasd_era_fatal;
      }

      /* return recoverable for all others */
      return dasd_era_recover;
}                       /* END dasd_3990_erp_examine_24 */

/*
 * DASD_3990_ERP_EXAMINE_32
 *
 * DESCRIPTION
 *   Checks only for fatal/no/recoverable error.
 *   A detailed examination of the sense data is done later outside
 *   the interrupt handler.
 *
 * RETURN VALUES
 *   dasd_era_none      no error
 *   dasd_era_fatal     for all fatal (unrecoverable errors)
 *   dasd_era_recover   for recoverable others.
 */
static dasd_era_t
dasd_3990_erp_examine_32(struct dasd_ccw_req * cqr, char *sense)
{

      struct dasd_device *device = cqr->device;

      switch (sense[25]) {
      case 0x00:
            return dasd_era_none;

      case 0x01:
            DEV_MESSAGE(KERN_ERR, device, "%s", "EXAMINE 32: fatal error");

            return dasd_era_fatal;

      default:

            return dasd_era_recover;
      }

}                       /* end dasd_3990_erp_examine_32 */

/*
 * DASD_3990_ERP_EXAMINE
 *
 * DESCRIPTION
 *   Checks only for fatal/no/recover error.
 *   A detailed examination of the sense data is done later outside
 *   the interrupt handler.
 *
 *   The logic is based on the 'IBM 3990 Storage Control  Reference' manual
 *   'Chapter 7. Error Recovery Procedures'.
 *
 * RETURN VALUES
 *   dasd_era_none      no error
 *   dasd_era_fatal     for all fatal (unrecoverable errors)
 *   dasd_era_recover   for all others.
 */
dasd_era_t
dasd_3990_erp_examine(struct dasd_ccw_req * cqr, struct irb * irb)
{

      char *sense = irb->ecw;
      dasd_era_t era = dasd_era_recover;
      struct dasd_device *device = cqr->device;

      /* check for successful execution first */
      if (irb->scsw.cstat == 0x00 &&
          irb->scsw.dstat == (DEV_STAT_CHN_END | DEV_STAT_DEV_END))
            return dasd_era_none;

      /* distinguish between 24 and 32 byte sense data */
      if (sense[27] & DASD_SENSE_BIT_0) {

            era = dasd_3990_erp_examine_24(cqr, sense);

      } else {

            era = dasd_3990_erp_examine_32(cqr, sense);

      }

      /* log the erp chain if fatal error occurred */
      if ((era == dasd_era_fatal) && (device->state >= DASD_STATE_READY)) {
            dasd_log_sense(cqr, irb);
            dasd_log_ccw(cqr, 0, irb->scsw.cpa);
      }

      return era;

}                       /* END dasd_3990_erp_examine */

/*
 *****************************************************************************
 * 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->device);
      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->device;

      DEV_MESSAGE(KERN_INFO, device,
                "blocking request queue for %is", expires/HZ);

      device->stopped |= DASD_STOPPED_PENDING;
      erp->status = DASD_CQR_QUEUED;

      dasd_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->device;

      /* 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_MESSAGE(KERN_ERR, device, "%s",
                      "is offline or not installed - "
                      "INTERVENTION REQUIRED!!");

            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->device;
      __u8 opm;

      /* try alternate valid path */
      opm = ccw_device_get_path_mask(device->cdev);
      //FIXME: start with get_opm ?
      if (erp->lpm == 0)
            erp->lpm = LPM_ANYPATH & ~(erp->irb.esw.esw0.sublog.lpum);
      else
            erp->lpm &= ~(erp->irb.esw.esw0.sublog.lpum);

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

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

            /* reset status to queued to handle the request again... */
            if (erp->status > DASD_CQR_QUEUED)
                  erp->status = DASD_CQR_QUEUED;
            erp->retries = 1;
      } else {
            DEV_MESSAGE(KERN_ERR, device,
                      "No alternate channel path left (lpum=%x / "
                      "opm=%x) -> permanent error",
                      erp->irb.esw.esw0.sublog.lpum, opm);

            /* post request with permanent error */
            if (erp->status > DASD_CQR_QUEUED)
                  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->device;
      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),
                                erp->device);
      if (IS_ERR(dctl_cqr)) {
            DEV_MESSAGE(KERN_ERR, device, "%s",
                      "Unable to allocate DCTL-CQR");
            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->function = dasd_3990_erp_DCTL;
      dctl_cqr->refers = erp;
      dctl_cqr->device = erp->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.
 *   If all alternate paths have been tried, the request is posted with a
 *   permanent error.
 *   Note: duplex handling is not implemented (yet).
 *
 *  PARAMETER
 *   erp          pointer to the current ERP
 *
 * RETURN VALUES
 *   erp          pointer to the 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);

      return erp;

}                       /* end dasd_3990_erp_action_1 */

/*
 * 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->device;

      /* 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) {

            DEV_MESSAGE(KERN_INFO, device, "%s",
                      "dasd_3990_erp_action_4: first time retry");

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

      } else {

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

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

                  dasd_3990_erp_block_queue(erp, 30*HZ);

                } else if (sense[25] == 0x1E) { /* busy */
                  DEV_MESSAGE(KERN_INFO, device,
                            "busy - redriving request later, "
                            "%d retries left",
                            erp->retries);
                        dasd_3990_erp_block_queue(erp, HZ);
            } else {

                  /* no state change pending - retry */
                  DEV_MESSAGE (KERN_INFO, device,
                             "redriving request immediately, "
                             "%d retries left",
                             erp->retries);
                  erp->status = DASD_CQR_QUEUED;
            }
      }

      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->device;
      char msg_format = (sense[7] & 0xF0);
      char msg_no = (sense[7] & 0x0F);

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

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

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

      case 0x30:        /* Format 3 - 3990 Control Checks */
            switch (msg_no) {
            case 0x0F:
                  DEV_MESSAGE(KERN_WARNING, device, "%s",
                            "FORMAT 3 - Allegiance terminated");
                  break;
            default:
                  DEV_MESSAGE(KERN_WARNING, device, "%s",
                            "FORMAT 3 - Reserved");
            }
            break;

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

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

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

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

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

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

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

      default:    /* unknown message format - should not happen */
              DEV_MESSAGE (KERN_WARNING, device,
                             "unknown message format %02x",
                             msg_format);
            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->device;

      erp->function = dasd_3990_erp_com_rej;

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

            DEV_MESSAGE(KERN_DEBUG, device, "%s",
                      "Command Reject - environmental data present");

            dasd_3990_handle_env_data(erp, sense);

            erp->retries = 5;

      } else {
            /* fatal error -  set status to FAILED */
            DEV_MESSAGE(KERN_ERR, device, "%s",
                      "Command Reject - Fatal error");

            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->device;

      /* 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 */
            DEV_MESSAGE(KERN_DEBUG, 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->device;

      erp->function = dasd_3990_erp_equip_check;

      if (sense[1] & SNS1_WRITE_INHIBITED) {

            DEV_MESSAGE(KERN_DEBUG, device, "%s",
                      "Write inhibited path encountered");

            /* vary path offline */
            DEV_MESSAGE(KERN_ERR, device, "%s",
                      "Path should be varied off-line. "
                      "This is not implemented yet \n - please report "
                      "to linux390@de.ibm.com");

            erp = dasd_3990_erp_action_1(erp);

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

            DEV_MESSAGE(KERN_DEBUG, 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) {

            DEV_MESSAGE(KERN_DEBUG, 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 */
            DEV_MESSAGE(KERN_DEBUG, 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->device;

      erp->function = dasd_3990_erp_data_check;

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

            /* issue message that the data has been corrected */
            DEV_MESSAGE(KERN_EMERG, device, "%s",
                      "Data recovered during retry with PCI "
                      "fetch mode active");

            /* 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) {

            DEV_MESSAGE(KERN_DEBUG, 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) {

            DEV_MESSAGE(KERN_DEBUG, device, "%s",
                      "Uncorrectable data check with internal "
                      "retry exhausted");

            erp = dasd_3990_erp_action_1(erp);

      } else {
            /* all other data checks */
            DEV_MESSAGE(KERN_DEBUG, 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->device;

      erp->function = dasd_3990_erp_overrun;

      DEV_MESSAGE(KERN_DEBUG, 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->device;

      erp->function = dasd_3990_erp_inv_format;

      if (sense[2] & SNS2_ENV_DATA_PRESENT) {

            DEV_MESSAGE(KERN_DEBUG, 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 {
            DEV_MESSAGE(KERN_ERR, device, "%s",
                      "Invalid Track Format - Fatal error should have "
                      "been handled within the interrupt handler");

            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->device;

      DEV_MESSAGE(KERN_ERR, device, "%s",
                "End-of-Cylinder - must never happen");

      /* 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->device;

      erp->function = dasd_3990_erp_env_data;

      DEV_MESSAGE(KERN_DEBUG, 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 = dasd_3990_erp_cleanup(erp, DASD_CQR_IN_IO);
      }

      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->device;

      DEV_MESSAGE(KERN_ERR, device, "%s",
                "No Record Found - Fatal error should "
                "have been handled within the interrupt handler");

      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->device;

      DEV_MESSAGE(KERN_ERR, device, "%s", "File Protected");

      return dasd_3990_erp_cleanup(erp, DASD_CQR_FAILED);

}                       /* end dasd_3990_erp_file_prot */

/*
 * 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->device;

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

      DEV_MESSAGE(KERN_DEBUG, 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->device;
      __u32 cpa = 0;
      struct dasd_ccw_req *cqr;
      struct dasd_ccw_req *erp;
      struct DE_eckd_data *DE_data;
      char *LO_data;          /* LO_eckd_data_t */
      struct ccw1 *ccw;

      DEV_MESSAGE(KERN_DEBUG, 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;
      }

      /* for imprecise ending just do default erp */
      if (sense[1] & 0x01) {

            DEV_MESSAGE(KERN_DEBUG, 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.cpa;

      if (cpa == 0) {

            DEV_MESSAGE(KERN_DEBUG, 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)) {
            DEV_MESSAGE(KERN_ERR, device, "%s", "Unable to allocate ERP");
            return dasd_3990_erp_cleanup(default_erp, DASD_CQR_FAILED);
      }

      /* use original DE */
      DE_data = erp->data;
      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)) {

            DEV_MESSAGE(KERN_ERR, device, "%s",
                      "BUG - this should not happen");

            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->function = dasd_3990_erp_action_1B_32;
      erp->refers = default_erp->refers;
      erp->device = 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->device;
      __u32 cpa = 0;
      struct dasd_ccw_req *cqr;
      struct dasd_ccw_req *erp;
      char *LO_data;          /* struct LO_eckd_data */
      struct ccw1 *ccw;

      DEV_MESSAGE(KERN_DEBUG, 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;
      }

      /* for imprecise ending just do default erp */
      if (sense[1] & 0x01) {

            DEV_MESSAGE(KERN_DEBUG, device, "%s",
                      "Imprecise ending is set - just retry");

            previous_erp->status = DASD_CQR_QUEUED;

            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.cpa;

      if (cpa == 0) {

            DEV_MESSAGE(KERN_DEBUG, device, "%s",
                      "Unable to determine address of the CCW "
                      "to be restarted");

            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)) {

            DEV_MESSAGE(KERN_ERR, device, "%s",
                      "BUG - this 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_QUEUED;

      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) {
                  /* reset the lpm and the status to be able to
                   * try further actions. */

                  erp->lpm = 0;

                  erp->status = DASD_CQR_ERROR;

            }
      }

      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 controler 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 */
            struct dasd_device *device = erp->device;

            DEV_MESSAGE(KERN_ERR, device, "%s",
                      "Set device to suspended duplex state should be "
                      "done!\n"
                      "This is not implemented yet (for compound ERP)"
                      " - please report to linux390@de.ibm.com");

      }

      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_ERROR)) {

            dasd_3990_erp_compound_path(erp, sense);
      }

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

            erp = dasd_3990_erp_compound_code(erp, sense);
      }

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

            dasd_3990_erp_compound_config(erp, sense);
      }

      /* if no compound action ERP specified, the request failed */
      if (erp->status == DASD_CQR_ERROR) {

            erp->status = DASD_CQR_FAILED;
      }

      return erp;

}                       /* end dasd_3990_erp_compound */

/*
 * 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->device;

      erp->function = dasd_3990_erp_inspect_32;

      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 */
                    DEV_MESSAGE(KERN_DEBUG, device, "%s",
                            "ERP called for successful request"
                            " - just retry");
                  break;

            case 0x01:  /* fatal error */
                  DEV_MESSAGE(KERN_ERR, device, "%s",
                            "Fatal error should have been "
                            "handled within the interrupt handler");

                  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 */
                  DEV_MESSAGE(KERN_ERR, device, "%s",
                            "update write command error - should not "
                            "happen;\n"
                            "Please send this message together with "
                            "the above sense data to linux390@de."
                            "ibm.com");

                  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 */
                  DEV_MESSAGE(KERN_ERR, device, "%s",
                            "next track outside defined extend - "
                            "should not happen;\n"
                            "Please send this message together with "
                            "the above sense data to linux390@de."
                            "ibm.com");

                  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_MESSAGE(KERN_EMERG, device, "%s",
                            "Data recovered during retry with PCI "
                            "fetch mode active");

                  /* 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 */
                  DEV_MESSAGE(KERN_DEBUG, 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 */
                        DEV_MESSAGE(KERN_DEBUG, 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 fuctions (24 and 32 byte sense)
 *****************************************************************************
 */

/*
 * 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;
      /* sense data are located in the refers record of the */
      /* already set up new ERP !                     */
      char *sense = erp->refers->irb.ecw;

      /* distinguish between 24 and 32 byte sense data */
      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 funtion adds an additional request block (ERP) to the head of
 *   the given cqr (or erp).
 *   This erp is initialized as an default erp (retry TIC)
 *
 * 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->device;
      struct ccw1 *ccw;

      /* allocate additional request block */
      struct dasd_ccw_req *erp;

      erp = dasd_alloc_erp_request((char *) &cqr->magic, 2, 0, cqr->device);
      if (IS_ERR(erp)) {
                if (cqr->retries <= 0) {
                    DEV_MESSAGE(KERN_ERR, device, "%s",
                            "Unable to allocate ERP request");
                  cqr->status = DASD_CQR_FAILED;
                        cqr->stopclk = get_clock ();
            } else {
                        DEV_MESSAGE (KERN_ERR, device,
                                     "Unable to allocate ERP request "
                             "(%i retries left)",
                                     cqr->retries);
                  dasd_set_timer(device, (HZ << 3));
                }
            return cqr;
      }

      /* 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->function = dasd_3990_erp_add_erp;
      erp->refers   = cqr;
      erp->device   = cqr->device;
      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);

      /* 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)
{

      /* check failed CCW */
      if (cqr1->irb.scsw.cpa != cqr2->irb.scsw.cpa) {
            //    return 0;   /* CCW doesn't match */
      }

      /* check sense data; byte 0-2,25,27 */
      if (!((memcmp (cqr1->irb.ecw, cqr2->irb.ecw, 3) == 0) &&
            (cqr1->irb.ecw[27] == cqr2->irb.ecw[27]) &&
            (cqr1->irb.ecw[25] == cqr2->irb.ecw[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->device;
      char *sense = erp->irb.ecw;

      /* 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_5) {

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

            if (!(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:
                        DEV_MESSAGE(KERN_DEBUG, device,
                                  "invalid subcommand modifier 0x%x "
                                  "for Diagnostic Control Command",
                                  sense[25]);
                  }
            }

            /* check for 32 byte sense ERP */
      } else if ((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_MESSAGE(KERN_ERR, device,
                      "no retries left for erp %p - "
                      "set status to FAILED", 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->device;
      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->list);

            erp_free = erp_done;
            erp_done = erp_done->refers;

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

      }                 /* end while */

      if (erp->retries > 0) {

            char *sense = erp->refers->irb.ecw;

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

                  erp = dasd_3990_erp_action_4(erp, sense);

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

                  erp = dasd_3990_update_1B(erp, sense);

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

                  erp = dasd_3990_erp_int_req(erp);

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

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

      } 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
 *   controll 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->device;
      __u32 cpa = cqr->irb.scsw.cpa;

#ifdef ERP_DEBUG
      /* print current erp_chain */
      DEV_MESSAGE(KERN_ERR, device, "%s",
                "ERP chain at BEGINNING of ERP-ACTION");
      {
            struct dasd_ccw_req *temp_erp = NULL;

            for (temp_erp = cqr;
                 temp_erp != NULL; temp_erp = temp_erp->refers) {

                  DEV_MESSAGE(KERN_ERR, device,
                            "   erp %p (%02x) refers to %p",
                            temp_erp, temp_erp->status,
                            temp_erp->refers);
            }
      }
#endif                        /* ERP_DEBUG */

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

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

            cqr->status = DASD_CQR_DONE;

            return cqr;
      }
      /* check if sense data are available */
      if (!cqr->irb.ecw) {
            DEV_MESSAGE(KERN_DEBUG, device,
                      "ERP called witout sense data avail ..."
                      "request %p - NO ERP possible", cqr);

            cqr->status = DASD_CQR_FAILED;

            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);
      } else {
            /* matching erp found - set all leading erp's to DONE */
            erp = dasd_3990_erp_handle_match_erp(cqr, erp);
      }

#ifdef ERP_DEBUG
      /* print current erp_chain */
      DEV_MESSAGE(KERN_ERR, device, "%s", "ERP chain at END of ERP-ACTION");
      {
            struct dasd_ccw_req *temp_erp = NULL;
            for (temp_erp = erp;
                 temp_erp != NULL; temp_erp = temp_erp->refers) {

                  DEV_MESSAGE(KERN_ERR, device,
                            "   erp %p (%02x) refers to %p",
                            temp_erp, temp_erp->status,
                            temp_erp->refers);
            }
      }
#endif                        /* ERP_DEBUG */

      if (erp->status == DASD_CQR_FAILED)
            dasd_log_ccw(erp, 1, cpa);

      /* enqueue added ERP request */
      if (erp->status == DASD_CQR_FILLED) {
            erp->status = DASD_CQR_QUEUED;
            list_add(&erp->list, &device->ccw_queue);
      }

      return erp;

}                       /* end dasd_3990_erp_action */

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