/*
 * File...........: linux/drivers/s390/block/dasd_eckd.c
 * Author(s)......: Holger Smolinski <Holger.Smolinski@de.ibm.com>
 *                  Horst Hummel <Horst.Hummel@de.ibm.com>
 *                  Carsten Otte <Cotte@de.ibm.com>
 *                  Martin Schwidefsky <schwidefsky@de.ibm.com>
 * Bugreports.to..: <Linux390@de.ibm.com>
 * Copyright IBM Corp. 1999, 2009
 * EMC Symmetrix ioctl Copyright EMC Corporation, 2008
 * Author.........: Nigel Hislop <hislop_nigel@emc.com>
 */

#define KMSG_COMPONENT "dasd-eckd"

#include <linux/stddef.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/hdreg.h>        /* HDIO_GETGEO                      */
#include <linux/bio.h>
#include <linux/module.h>
#include <linux/compat.h>
#include <linux/init.h>

#include <asm/debug.h>
#include <asm/idals.h>
#include <asm/ebcdic.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/cio.h>
#include <asm/ccwdev.h>
#include <asm/itcw.h>

#include "dasd_int.h"
#include "dasd_eckd.h"
#include "../cio/chsc.h"


#ifdef PRINTK_HEADER
#undef PRINTK_HEADER
#endif                          /* PRINTK_HEADER */
#define PRINTK_HEADER "dasd(eckd):"

#define ECKD_C0(i) (i->home_bytes)
#define ECKD_F(i) (i->formula)
#define ECKD_F1(i) (ECKD_F(i)==0x01?(i->factors.f_0x01.f1):\
                    (i->factors.f_0x02.f1))
#define ECKD_F2(i) (ECKD_F(i)==0x01?(i->factors.f_0x01.f2):\
                    (i->factors.f_0x02.f2))
#define ECKD_F3(i) (ECKD_F(i)==0x01?(i->factors.f_0x01.f3):\
                    (i->factors.f_0x02.f3))
#define ECKD_F4(i) (ECKD_F(i)==0x02?(i->factors.f_0x02.f4):0)
#define ECKD_F5(i) (ECKD_F(i)==0x02?(i->factors.f_0x02.f5):0)
#define ECKD_F6(i) (i->factor6)
#define ECKD_F7(i) (i->factor7)
#define ECKD_F8(i) (i->factor8)

/*
 * raw track access always map to 64k in memory
 * so it maps to 16 blocks of 4k per track
 */
#define DASD_RAW_BLOCK_PER_TRACK 16
#define DASD_RAW_BLOCKSIZE 4096
/* 64k are 128 x 512 byte sectors  */
#define DASD_RAW_SECTORS_PER_TRACK 128

MODULE_LICENSE("GPL");

static struct dasd_discipline dasd_eckd_discipline;

/* The ccw bus type uses this table to find devices that it sends to
 * dasd_eckd_probe */
static struct ccw_device_id dasd_eckd_ids[] = {
        { CCW_DEVICE_DEVTYPE (0x3990, 0, 0x3390, 0), .driver_info = 0x1},
        { CCW_DEVICE_DEVTYPE (0x2105, 0, 0x3390, 0), .driver_info = 0x2},
        { CCW_DEVICE_DEVTYPE (0x3880, 0, 0x3380, 0), .driver_info = 0x3},
        { CCW_DEVICE_DEVTYPE (0x3990, 0, 0x3380, 0), .driver_info = 0x4},
        { CCW_DEVICE_DEVTYPE (0x2105, 0, 0x3380, 0), .driver_info = 0x5},
        { CCW_DEVICE_DEVTYPE (0x9343, 0, 0x9345, 0), .driver_info = 0x6},
        { CCW_DEVICE_DEVTYPE (0x2107, 0, 0x3390, 0), .driver_info = 0x7},
        { CCW_DEVICE_DEVTYPE (0x2107, 0, 0x3380, 0), .driver_info = 0x8},
        { CCW_DEVICE_DEVTYPE (0x1750, 0, 0x3390, 0), .driver_info = 0x9},
        { CCW_DEVICE_DEVTYPE (0x1750, 0, 0x3380, 0), .driver_info = 0xa},
        { /* end of list */ },
};

MODULE_DEVICE_TABLE(ccw, dasd_eckd_ids);

static struct ccw_driver dasd_eckd_driver; /* see below */

#define INIT_CQR_OK 0
#define INIT_CQR_UNFORMATTED 1
#define INIT_CQR_ERROR 2

/* emergency request for reserve/release */
static struct {
        struct dasd_ccw_req cqr;
        struct ccw1 ccw;
        char data[32];
} *dasd_reserve_req;
static DEFINE_MUTEX(dasd_reserve_mutex);

/* definitions for the path verification worker */
struct path_verification_work_data {
        struct work_struct worker;
        struct dasd_device *device;
        struct dasd_ccw_req cqr;
        struct ccw1 ccw;
        __u8 rcd_buffer[DASD_ECKD_RCD_DATA_SIZE];
        int isglobal;
        __u8 tbvpm;
};
static struct path_verification_work_data *path_verification_worker;
static DEFINE_MUTEX(dasd_path_verification_mutex);

/* initial attempt at a probe function. this can be simplified once
 * the other detection code is gone */
static int
dasd_eckd_probe (struct ccw_device *cdev)
{
        int ret;

        /* set ECKD specific ccw-device options */
        ret = ccw_device_set_options(cdev, CCWDEV_ALLOW_FORCE |
                                     CCWDEV_DO_PATHGROUP | CCWDEV_DO_MULTIPATH);
        if (ret) {
                DBF_EVENT_DEVID(DBF_WARNING, cdev, "%s",
                                "dasd_eckd_probe: could not set "
                                "ccw-device options");
                return ret;
        }
        ret = dasd_generic_probe(cdev, &dasd_eckd_discipline);
        return ret;
}

static int
dasd_eckd_set_online(struct ccw_device *cdev)
{
        return dasd_generic_set_online(cdev, &dasd_eckd_discipline);
}

static const int sizes_trk0[] = { 28, 148, 84 };
#define LABEL_SIZE 140

static inline unsigned int
round_up_multiple(unsigned int no, unsigned int mult)
{
        int rem = no % mult;
        return (rem ? no - rem + mult : no);
}

static inline unsigned int
ceil_quot(unsigned int d1, unsigned int d2)
{
        return (d1 + (d2 - 1)) / d2;
}

static unsigned int
recs_per_track(struct dasd_eckd_characteristics * rdc,
               unsigned int kl, unsigned int dl)
{
        int dn, kn;

        switch (rdc->dev_type) {
        case 0x3380:
                if (kl)
                        return 1499 / (15 + 7 + ceil_quot(kl + 12, 32) +
                                       ceil_quot(dl + 12, 32));
                else
                        return 1499 / (15 + ceil_quot(dl + 12, 32));
        case 0x3390:
                dn = ceil_quot(dl + 6, 232) + 1;
                if (kl) {
                        kn = ceil_quot(kl + 6, 232) + 1;
                        return 1729 / (10 + 9 + ceil_quot(kl + 6 * kn, 34) +
                                       9 + ceil_quot(dl + 6 * dn, 34));
                } else
                        return 1729 / (10 + 9 + ceil_quot(dl + 6 * dn, 34));
        case 0x9345:
                dn = ceil_quot(dl + 6, 232) + 1;
                if (kl) {
                        kn = ceil_quot(kl + 6, 232) + 1;
                        return 1420 / (18 + 7 + ceil_quot(kl + 6 * kn, 34) +
                                       ceil_quot(dl + 6 * dn, 34));
                } else
                        return 1420 / (18 + 7 + ceil_quot(dl + 6 * dn, 34));
        }
        return 0;
}

static void set_ch_t(struct ch_t *geo, __u32 cyl, __u8 head)
{
        geo->cyl = (__u16) cyl;
        geo->head = cyl >> 16;
        geo->head <<= 4;
        geo->head |= head;
}

static int
check_XRC (struct ccw1         *de_ccw,
           struct DE_eckd_data *data,
           struct dasd_device  *device)
{
        struct dasd_eckd_private *private;
        int rc;

        private = (struct dasd_eckd_private *) device->private;
        if (!private->rdc_data.facilities.XRC_supported)
                return 0;

        /* switch on System Time Stamp - needed for XRC Support */
        data->ga_extended |= 0x08; /* switch on 'Time Stamp Valid'   */
        data->ga_extended |= 0x02; /* switch on 'Extended Parameter' */

        rc = get_sync_clock(&data->ep_sys_time);
        /* Ignore return code if sync clock is switched off. */
        if (rc == -ENOSYS || rc == -EACCES)
                rc = 0;

        de_ccw->count = sizeof(struct DE_eckd_data);
        de_ccw->flags |= CCW_FLAG_SLI;
        return rc;
}

static int
define_extent(struct ccw1 *ccw, struct DE_eckd_data *data, unsigned int trk,
              unsigned int totrk, int cmd, struct dasd_device *device)
{
        struct dasd_eckd_private *private;
        u32 begcyl, endcyl;
        u16 heads, beghead, endhead;
        int rc = 0;

        private = (struct dasd_eckd_private *) device->private;

        ccw->cmd_code = DASD_ECKD_CCW_DEFINE_EXTENT;
        ccw->flags = 0;
        ccw->count = 16;
        ccw->cda = (__u32) __pa(data);

        memset(data, 0, sizeof(struct DE_eckd_data));
        switch (cmd) {
        case DASD_ECKD_CCW_READ_HOME_ADDRESS:
        case DASD_ECKD_CCW_READ_RECORD_ZERO:
        case DASD_ECKD_CCW_READ:
        case DASD_ECKD_CCW_READ_MT:
        case DASD_ECKD_CCW_READ_CKD:
        case DASD_ECKD_CCW_READ_CKD_MT:
        case DASD_ECKD_CCW_READ_KD:
        case DASD_ECKD_CCW_READ_KD_MT:
        case DASD_ECKD_CCW_READ_COUNT:
                data->mask.perm = 0x1;
                data->attributes.operation = private->attrib.operation;
                break;
        case DASD_ECKD_CCW_WRITE:
        case DASD_ECKD_CCW_WRITE_MT:
        case DASD_ECKD_CCW_WRITE_KD:
        case DASD_ECKD_CCW_WRITE_KD_MT:
                data->mask.perm = 0x02;
                data->attributes.operation = private->attrib.operation;
                rc = check_XRC (ccw, data, device);
                break;
        case DASD_ECKD_CCW_WRITE_CKD:
        case DASD_ECKD_CCW_WRITE_CKD_MT:
                data->attributes.operation = DASD_BYPASS_CACHE;
                rc = check_XRC (ccw, data, device);
                break;
        case DASD_ECKD_CCW_ERASE:
        case DASD_ECKD_CCW_WRITE_HOME_ADDRESS:
        case DASD_ECKD_CCW_WRITE_RECORD_ZERO:
                data->mask.perm = 0x3;
                data->mask.auth = 0x1;
                data->attributes.operation = DASD_BYPASS_CACHE;
                rc = check_XRC (ccw, data, device);
                break;
        default:
                dev_err(&device->cdev->dev,
                        "0x%x is not a known command\n", cmd);
                break;
        }

        data->attributes.mode = 0x3;    /* ECKD */

        if ((private->rdc_data.cu_type == 0x2105 ||
             private->rdc_data.cu_type == 0x2107 ||
             private->rdc_data.cu_type == 0x1750)
            && !(private->uses_cdl && trk < 2))
                data->ga_extended |= 0x40; /* Regular Data Format Mode */

        heads = private->rdc_data.trk_per_cyl;
        begcyl = trk / heads;
        beghead = trk % heads;
        endcyl = totrk / heads;
        endhead = totrk % heads;

        /* check for sequential prestage - enhance cylinder range */
        if (data->attributes.operation == DASD_SEQ_PRESTAGE ||
            data->attributes.operation == DASD_SEQ_ACCESS) {

                if (endcyl + private->attrib.nr_cyl < private->real_cyl)
                        endcyl += private->attrib.nr_cyl;
                else
                        endcyl = (private->real_cyl - 1);
        }

        set_ch_t(&data->beg_ext, begcyl, beghead);
        set_ch_t(&data->end_ext, endcyl, endhead);
        return rc;
}

static int check_XRC_on_prefix(struct PFX_eckd_data *pfxdata,
                               struct dasd_device  *device)
{
        struct dasd_eckd_private *private;
        int rc;

        private = (struct dasd_eckd_private *) device->private;
        if (!private->rdc_data.facilities.XRC_supported)
                return 0;

        /* switch on System Time Stamp - needed for XRC Support */
        pfxdata->define_extent.ga_extended |= 0x08; /* 'Time Stamp Valid'   */
        pfxdata->define_extent.ga_extended |= 0x02; /* 'Extended Parameter' */
        pfxdata->validity.time_stamp = 1;           /* 'Time Stamp Valid'   */

        rc = get_sync_clock(&pfxdata->define_extent.ep_sys_time);
        /* Ignore return code if sync clock is switched off. */
        if (rc == -ENOSYS || rc == -EACCES)
                rc = 0;
        return rc;
}

static void fill_LRE_data(struct LRE_eckd_data *data, unsigned int trk,
                          unsigned int rec_on_trk, int count, int cmd,
                          struct dasd_device *device, unsigned int reclen,
                          unsigned int tlf)
{
        struct dasd_eckd_private *private;
        int sector;
        int dn, d;

        private = (struct dasd_eckd_private *) device->private;

        memset(data, 0, sizeof(*data));
        sector = 0;
        if (rec_on_trk) {
                switch (private->rdc_data.dev_type) {
                case 0x3390:
                        dn = ceil_quot(reclen + 6, 232);
                        d = 9 + ceil_quot(reclen + 6 * (dn + 1), 34);
                        sector = (49 + (rec_on_trk - 1) * (10 + d)) / 8;
                        break;
                case 0x3380:
                        d = 7 + ceil_quot(reclen + 12, 32);
                        sector = (39 + (rec_on_trk - 1) * (8 + d)) / 7;
                        break;
                }
        }
        data->sector = sector;
        /* note: meaning of count depends on the operation
         *       for record based I/O it's the number of records, but for
         *       track based I/O it's the number of tracks
         */
        data->count = count;
        switch (cmd) {
        case DASD_ECKD_CCW_WRITE_HOME_ADDRESS:
                data->operation.orientation = 0x3;
                data->operation.operation = 0x03;
                break;
        case DASD_ECKD_CCW_READ_HOME_ADDRESS:
                data->operation.orientation = 0x3;
                data->operation.operation = 0x16;
                break;
        case DASD_ECKD_CCW_WRITE_RECORD_ZERO:
                data->operation.orientation = 0x1;
                data->operation.operation = 0x03;
                data->count++;
                break;
        case DASD_ECKD_CCW_READ_RECORD_ZERO:
                data->operation.orientation = 0x3;
                data->operation.operation = 0x16;
                data->count++;
                break;
        case DASD_ECKD_CCW_WRITE:
        case DASD_ECKD_CCW_WRITE_MT:
        case DASD_ECKD_CCW_WRITE_KD:
        case DASD_ECKD_CCW_WRITE_KD_MT:
                data->auxiliary.length_valid = 0x1;
                data->length = reclen;
                data->operation.operation = 0x01;
                break;
        case DASD_ECKD_CCW_WRITE_CKD:
        case DASD_ECKD_CCW_WRITE_CKD_MT:
                data->auxiliary.length_valid = 0x1;
                data->length = reclen;
                data->operation.operation = 0x03;
                break;
        case DASD_ECKD_CCW_WRITE_FULL_TRACK:
                data->operation.orientation = 0x0;
                data->operation.operation = 0x3F;
                data->extended_operation = 0x11;
                data->length = 0;
                data->extended_parameter_length = 0x02;
                if (data->count > 8) {
                        data->extended_parameter[0] = 0xFF;
                        data->extended_parameter[1] = 0xFF;
                        data->extended_parameter[1] <<= (16 - count);
                } else {
                        data->extended_parameter[0] = 0xFF;
                        data->extended_parameter[0] <<= (8 - count);
                        data->extended_parameter[1] = 0x00;
                }
                data->sector = 0xFF;
                break;
        case DASD_ECKD_CCW_WRITE_TRACK_DATA:
                data->auxiliary.length_valid = 0x1;
                data->length = reclen;  /* not tlf, as one might think */
                data->operation.operation = 0x3F;
                data->extended_operation = 0x23;
                break;
        case DASD_ECKD_CCW_READ:
        case DASD_ECKD_CCW_READ_MT:
        case DASD_ECKD_CCW_READ_KD:
        case DASD_ECKD_CCW_READ_KD_MT:
                data->auxiliary.length_valid = 0x1;
                data->length = reclen;
                data->operation.operation = 0x06;
                break;
        case DASD_ECKD_CCW_READ_CKD:
        case DASD_ECKD_CCW_READ_CKD_MT:
                data->auxiliary.length_valid = 0x1;
                data->length = reclen;
                data->operation.operation = 0x16;
                break;
        case DASD_ECKD_CCW_READ_COUNT:
                data->operation.operation = 0x06;
                break;
        case DASD_ECKD_CCW_READ_TRACK:
                data->operation.orientation = 0x1;
                data->operation.operation = 0x0C;
                data->extended_parameter_length = 0;
                data->sector = 0xFF;
                break;
        case DASD_ECKD_CCW_READ_TRACK_DATA:
                data->auxiliary.length_valid = 0x1;
                data->length = tlf;
                data->operation.operation = 0x0C;
                break;
        case DASD_ECKD_CCW_ERASE:
                data->length = reclen;
                data->auxiliary.length_valid = 0x1;
                data->operation.operation = 0x0b;
                break;
        default:
                DBF_DEV_EVENT(DBF_ERR, device,
                            "fill LRE unknown opcode 0x%x", cmd);
                BUG();
        }
        set_ch_t(&data->seek_addr,
                 trk / private->rdc_data.trk_per_cyl,
                 trk % private->rdc_data.trk_per_cyl);
        data->search_arg.cyl = data->seek_addr.cyl;
        data->search_arg.head = data->seek_addr.head;
        data->search_arg.record = rec_on_trk;
}

static int prefix_LRE(struct ccw1 *ccw, struct PFX_eckd_data *pfxdata,
                      unsigned int trk, unsigned int totrk, int cmd,
                      struct dasd_device *basedev, struct dasd_device *startdev,
                      unsigned char format, unsigned int rec_on_trk, int count,
                      unsigned int blksize, unsigned int tlf)
{
        struct dasd_eckd_private *basepriv, *startpriv;
        struct DE_eckd_data *dedata;
        struct LRE_eckd_data *lredata;
        u32 begcyl, endcyl;
        u16 heads, beghead, endhead;
        int rc = 0;

        basepriv = (struct dasd_eckd_private *) basedev->private;
        startpriv = (struct dasd_eckd_private *) startdev->private;
        dedata = &pfxdata->define_extent;
        lredata = &pfxdata->locate_record;

        ccw->cmd_code = DASD_ECKD_CCW_PFX;
        ccw->flags = 0;
        if (cmd == DASD_ECKD_CCW_WRITE_FULL_TRACK) {
                ccw->count = sizeof(*pfxdata) + 2;
                ccw->cda = (__u32) __pa(pfxdata);
                memset(pfxdata, 0, sizeof(*pfxdata) + 2);
        } else {
                ccw->count = sizeof(*pfxdata);
                ccw->cda = (__u32) __pa(pfxdata);
                memset(pfxdata, 0, sizeof(*pfxdata));
        }

        /* prefix data */
        if (format > 1) {
                DBF_DEV_EVENT(DBF_ERR, basedev,
                              "PFX LRE unknown format 0x%x", format);
                BUG();
                return -EINVAL;
        }
        pfxdata->format = format;
        pfxdata->base_address = basepriv->ned->unit_addr;
        pfxdata->base_lss = basepriv->ned->ID;
        pfxdata->validity.define_extent = 1;

        /* private uid is kept up to date, conf_data may be outdated */
        if (startpriv->uid.type != UA_BASE_DEVICE) {
                pfxdata->validity.verify_base = 1;
                if (startpriv->uid.type == UA_HYPER_PAV_ALIAS)
                        pfxdata->validity.hyper_pav = 1;
        }

        /* define extend data (mostly)*/
        switch (cmd) {
        case DASD_ECKD_CCW_READ_HOME_ADDRESS:
        case DASD_ECKD_CCW_READ_RECORD_ZERO:
        case DASD_ECKD_CCW_READ:
        case DASD_ECKD_CCW_READ_MT:
        case DASD_ECKD_CCW_READ_CKD:
        case DASD_ECKD_CCW_READ_CKD_MT:
        case DASD_ECKD_CCW_READ_KD:
        case DASD_ECKD_CCW_READ_KD_MT:
        case DASD_ECKD_CCW_READ_COUNT:
                dedata->mask.perm = 0x1;
                dedata->attributes.operation = basepriv->attrib.operation;
                break;
        case DASD_ECKD_CCW_READ_TRACK:
        case DASD_ECKD_CCW_READ_TRACK_DATA:
                dedata->mask.perm = 0x1;
                dedata->attributes.operation = basepriv->attrib.operation;
                dedata->blk_size = 0;
                break;
        case DASD_ECKD_CCW_WRITE:
        case DASD_ECKD_CCW_WRITE_MT:
        case DASD_ECKD_CCW_WRITE_KD:
        case DASD_ECKD_CCW_WRITE_KD_MT:
                dedata->mask.perm = 0x02;
                dedata->attributes.operation = basepriv->attrib.operation;
                rc = check_XRC_on_prefix(pfxdata, basedev);
                break;
        case DASD_ECKD_CCW_WRITE_CKD:
        case DASD_ECKD_CCW_WRITE_CKD_MT:
                dedata->attributes.operation = DASD_BYPASS_CACHE;
                rc = check_XRC_on_prefix(pfxdata, basedev);
                break;
        case DASD_ECKD_CCW_ERASE:
        case DASD_ECKD_CCW_WRITE_HOME_ADDRESS:
        case DASD_ECKD_CCW_WRITE_RECORD_ZERO:
                dedata->mask.perm = 0x3;
                dedata->mask.auth = 0x1;
                dedata->attributes.operation = DASD_BYPASS_CACHE;
                rc = check_XRC_on_prefix(pfxdata, basedev);
                break;
        case DASD_ECKD_CCW_WRITE_FULL_TRACK:
                dedata->mask.perm = 0x03;
                dedata->attributes.operation = basepriv->attrib.operation;
                dedata->blk_size = 0;
                break;
        case DASD_ECKD_CCW_WRITE_TRACK_DATA:
                dedata->mask.perm = 0x02;
                dedata->attributes.operation = basepriv->attrib.operation;
                dedata->blk_size = blksize;
                rc = check_XRC_on_prefix(pfxdata, basedev);
                break;
        default:
                DBF_DEV_EVENT(DBF_ERR, basedev,
                            "PFX LRE unknown opcode 0x%x", cmd);
                BUG();
                return -EINVAL;
        }

        dedata->attributes.mode = 0x3;  /* ECKD */

        if ((basepriv->rdc_data.cu_type == 0x2105 ||
             basepriv->rdc_data.cu_type == 0x2107 ||
             basepriv->rdc_data.cu_type == 0x1750)
            && !(basepriv->uses_cdl && trk < 2))
                dedata->ga_extended |= 0x40; /* Regular Data Format Mode */

        heads = basepriv->rdc_data.trk_per_cyl;
        begcyl = trk / heads;
        beghead = trk % heads;
        endcyl = totrk / heads;
        endhead = totrk % heads;

        /* check for sequential prestage - enhance cylinder range */
        if (dedata->attributes.operation == DASD_SEQ_PRESTAGE ||
            dedata->attributes.operation == DASD_SEQ_ACCESS) {

                if (endcyl + basepriv->attrib.nr_cyl < basepriv->real_cyl)
                        endcyl += basepriv->attrib.nr_cyl;
                else
                        endcyl = (basepriv->real_cyl - 1);
        }

        set_ch_t(&dedata->beg_ext, begcyl, beghead);
        set_ch_t(&dedata->end_ext, endcyl, endhead);

        if (format == 1) {
                fill_LRE_data(lredata, trk, rec_on_trk, count, cmd,
                              basedev, blksize, tlf);
        }

        return rc;
}

static int prefix(struct ccw1 *ccw, struct PFX_eckd_data *pfxdata,
                  unsigned int trk, unsigned int totrk, int cmd,
                  struct dasd_device *basedev, struct dasd_device *startdev)
{
        return prefix_LRE(ccw, pfxdata, trk, totrk, cmd, basedev, startdev,
                          0, 0, 0, 0, 0);
}

static void
locate_record(struct ccw1 *ccw, struct LO_eckd_data *data, unsigned int trk,
              unsigned int rec_on_trk, int no_rec, int cmd,
              struct dasd_device * device, int reclen)
{
        struct dasd_eckd_private *private;
        int sector;
        int dn, d;

        private = (struct dasd_eckd_private *) device->private;

        DBF_DEV_EVENT(DBF_INFO, device,
                  "Locate: trk %d, rec %d, no_rec %d, cmd %d, reclen %d",
                  trk, rec_on_trk, no_rec, cmd, reclen);

        ccw->cmd_code = DASD_ECKD_CCW_LOCATE_RECORD;
        ccw->flags = 0;
        ccw->count = 16;
        ccw->cda = (__u32) __pa(data);

        memset(data, 0, sizeof(struct LO_eckd_data));
        sector = 0;
        if (rec_on_trk) {
                switch (private->rdc_data.dev_type) {
                case 0x3390:
                        dn = ceil_quot(reclen + 6, 232);
                        d = 9 + ceil_quot(reclen + 6 * (dn + 1), 34);
                        sector = (49 + (rec_on_trk - 1) * (10 + d)) / 8;
                        break;
                case 0x3380:
                        d = 7 + ceil_quot(reclen + 12, 32);
                        sector = (39 + (rec_on_trk - 1) * (8 + d)) / 7;
                        break;
                }
        }
        data->sector = sector;
        data->count = no_rec;
        switch (cmd) {
        case DASD_ECKD_CCW_WRITE_HOME_ADDRESS:
                data->operation.orientation = 0x3;
                data->operation.operation = 0x03;
                break;
        case DASD_ECKD_CCW_READ_HOME_ADDRESS:
                data->operation.orientation = 0x3;
                data->operation.operation = 0x16;
                break;
        case DASD_ECKD_CCW_WRITE_RECORD_ZERO:
                data->operation.orientation = 0x1;
                data->operation.operation = 0x03;
                data->count++;
                break;
        case DASD_ECKD_CCW_READ_RECORD_ZERO:
                data->operation.orientation = 0x3;
                data->operation.operation = 0x16;
                data->count++;
                break;
        case DASD_ECKD_CCW_WRITE:
        case DASD_ECKD_CCW_WRITE_MT:
        case DASD_ECKD_CCW_WRITE_KD:
        case DASD_ECKD_CCW_WRITE_KD_MT:
                data->auxiliary.last_bytes_used = 0x1;
                data->length = reclen;
                data->operation.operation = 0x01;
                break;
        case DASD_ECKD_CCW_WRITE_CKD:
        case DASD_ECKD_CCW_WRITE_CKD_MT:
                data->auxiliary.last_bytes_used = 0x1;
                data->length = reclen;
                data->operation.operation = 0x03;
                break;
        case DASD_ECKD_CCW_READ:
        case DASD_ECKD_CCW_READ_MT:
        case DASD_ECKD_CCW_READ_KD:
        case DASD_ECKD_CCW_READ_KD_MT:
                data->auxiliary.last_bytes_used = 0x1;
                data->length = reclen;
                data->operation.operation = 0x06;
                break;
        case DASD_ECKD_CCW_READ_CKD:
        case DASD_ECKD_CCW_READ_CKD_MT:
                data->auxiliary.last_bytes_used = 0x1;
                data->length = reclen;
                data->operation.operation = 0x16;
                break;
        case DASD_ECKD_CCW_READ_COUNT:
                data->operation.operation = 0x06;
                break;
        case DASD_ECKD_CCW_ERASE:
                data->length = reclen;
                data->auxiliary.last_bytes_used = 0x1;
                data->operation.operation = 0x0b;
                break;
        default:
                DBF_DEV_EVENT(DBF_ERR, device, "unknown locate record "
                              "opcode 0x%x", cmd);
        }
        set_ch_t(&data->seek_addr,
                 trk / private->rdc_data.trk_per_cyl,
                 trk % private->rdc_data.trk_per_cyl);
        data->search_arg.cyl = data->seek_addr.cyl;
        data->search_arg.head = data->seek_addr.head;
        data->search_arg.record = rec_on_trk;
}

/*
 * Returns 1 if the block is one of the special blocks that needs
 * to get read/written with the KD variant of the command.
 * That is DASD_ECKD_READ_KD_MT instead of DASD_ECKD_READ_MT and
 * DASD_ECKD_WRITE_KD_MT instead of DASD_ECKD_WRITE_MT.
 * Luckily the KD variants differ only by one bit (0x08) from the
 * normal variant. So don't wonder about code like:
 * if (dasd_eckd_cdl_special(blk_per_trk, recid))
 *         ccw->cmd_code |= 0x8;
 */
static inline int
dasd_eckd_cdl_special(int blk_per_trk, int recid)
{
        if (recid < 3)
                return 1;
        if (recid < blk_per_trk)
                return 0;
        if (recid < 2 * blk_per_trk)
                return 1;
        return 0;
}

/*
 * Returns the record size for the special blocks of the cdl format.
 * Only returns something useful if dasd_eckd_cdl_special is true
 * for the recid.
 */
static inline int
dasd_eckd_cdl_reclen(int recid)
{
        if (recid < 3)
                return sizes_trk0[recid];
        return LABEL_SIZE;
}
/* create unique id from private structure. */
static void create_uid(struct dasd_eckd_private *private)
{
        int count;
        struct dasd_uid *uid;

        uid = &private->uid;
        memset(uid, 0, sizeof(struct dasd_uid));
        memcpy(uid->vendor, private->ned->HDA_manufacturer,
               sizeof(uid->vendor) - 1);
        EBCASC(uid->vendor, sizeof(uid->vendor) - 1);
        memcpy(uid->serial, private->ned->HDA_location,
               sizeof(uid->serial) - 1);
        EBCASC(uid->serial, sizeof(uid->serial) - 1);
        uid->ssid = private->gneq->subsystemID;
        uid->real_unit_addr = private->ned->unit_addr;
        if (private->sneq) {
                uid->type = private->sneq->sua_flags;
                if (uid->type == UA_BASE_PAV_ALIAS)
                        uid->base_unit_addr = private->sneq->base_unit_addr;
        } else {
                uid->type = UA_BASE_DEVICE;
        }
        if (private->vdsneq) {
                for (count = 0; count < 16; count++) {
                        sprintf(uid->vduit+2*count, "%02x",
                                private->vdsneq->uit[count]);
                }
        }
}

/*
 * Generate device unique id that specifies the physical device.
 */
static int dasd_eckd_generate_uid(struct dasd_device *device)
{
        struct dasd_eckd_private *private;
        unsigned long flags;

        private = (struct dasd_eckd_private *) device->private;
        if (!private)
                return -ENODEV;
        if (!private->ned || !private->gneq)
                return -ENODEV;
        spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
        create_uid(private);
        spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
        return 0;
}

static int dasd_eckd_get_uid(struct dasd_device *device, struct dasd_uid *uid)
{
        struct dasd_eckd_private *private;
        unsigned long flags;

        if (device->private) {
                private = (struct dasd_eckd_private *)device->private;
                spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
                *uid = private->uid;
                spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
                return 0;
        }
        return -EINVAL;
}

/*
 * compare device UID with data of a given dasd_eckd_private structure
 * return 0 for match
 */
static int dasd_eckd_compare_path_uid(struct dasd_device *device,
                                      struct dasd_eckd_private *private)
{
        struct dasd_uid device_uid;

        create_uid(private);
        dasd_eckd_get_uid(device, &device_uid);

        return memcmp(&device_uid, &private->uid, sizeof(struct dasd_uid));
}

static void dasd_eckd_fill_rcd_cqr(struct dasd_device *device,
                                   struct dasd_ccw_req *cqr,
                                   __u8 *rcd_buffer,
                                   __u8 lpm)
{
        struct ccw1 *ccw;
        /*
         * buffer has to start with EBCDIC "V1.0" to show
         * support for virtual device SNEQ
         */
        rcd_buffer[0] = 0xE5;
        rcd_buffer[1] = 0xF1;
        rcd_buffer[2] = 0x4B;
        rcd_buffer[3] = 0xF0;

        ccw = cqr->cpaddr;
        ccw->cmd_code = DASD_ECKD_CCW_RCD;
        ccw->flags = 0;
        ccw->cda = (__u32)(addr_t)rcd_buffer;
        ccw->count = DASD_ECKD_RCD_DATA_SIZE;
        cqr->magic = DASD_ECKD_MAGIC;

        cqr->startdev = device;
        cqr->memdev = device;
        cqr->block = NULL;
        cqr->expires = 10*HZ;
        cqr->lpm = lpm;
        cqr->retries = 256;
        cqr->buildclk = get_clock();
        cqr->status = DASD_CQR_FILLED;
        set_bit(DASD_CQR_VERIFY_PATH, &cqr->flags);
}

/*
 * Wakeup helper for read_conf
 * if the cqr is not done and needs some error recovery
 * the buffer has to be re-initialized with the EBCDIC "V1.0"
 * to show support for virtual device SNEQ
 */
static void read_conf_cb(struct dasd_ccw_req *cqr, void *data)
{
        struct ccw1 *ccw;
        __u8 *rcd_buffer;

        if (cqr->status !=  DASD_CQR_DONE) {
                ccw = cqr->cpaddr;
                rcd_buffer = (__u8 *)((addr_t) ccw->cda);
                memset(rcd_buffer, 0, sizeof(*rcd_buffer));

                rcd_buffer[0] = 0xE5;
                rcd_buffer[1] = 0xF1;
                rcd_buffer[2] = 0x4B;
                rcd_buffer[3] = 0xF0;
        }
        dasd_wakeup_cb(cqr, data);
}

static int dasd_eckd_read_conf_immediately(struct dasd_device *device,
                                           struct dasd_ccw_req *cqr,
                                           __u8 *rcd_buffer,
                                           __u8 lpm)
{
        struct ciw *ciw;
        int rc;
        /*
         * sanity check: scan for RCD command in extended SenseID data
         * some devices do not support RCD
         */
        ciw = ccw_device_get_ciw(device->cdev, CIW_TYPE_RCD);
        if (!ciw || ciw->cmd != DASD_ECKD_CCW_RCD)
                return -EOPNOTSUPP;

        dasd_eckd_fill_rcd_cqr(device, cqr, rcd_buffer, lpm);
        clear_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
        set_bit(DASD_CQR_ALLOW_SLOCK, &cqr->flags);
        cqr->retries = 5;
        cqr->callback = read_conf_cb;
        rc = dasd_sleep_on_immediatly(cqr);
        return rc;
}

static int dasd_eckd_read_conf_lpm(struct dasd_device *device,
                                   void **rcd_buffer,
                                   int *rcd_buffer_size, __u8 lpm)
{
        struct ciw *ciw;
        char *rcd_buf = NULL;
        int ret;
        struct dasd_ccw_req *cqr;

        /*
         * sanity check: scan for RCD command in extended SenseID data
         * some devices do not support RCD
         */
        ciw = ccw_device_get_ciw(device->cdev, CIW_TYPE_RCD);
        if (!ciw || ciw->cmd != DASD_ECKD_CCW_RCD) {
                ret = -EOPNOTSUPP;
                goto out_error;
        }
        rcd_buf = kzalloc(DASD_ECKD_RCD_DATA_SIZE, GFP_KERNEL | GFP_DMA);
        if (!rcd_buf) {
                ret = -ENOMEM;
                goto out_error;
        }
        cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 1 /* RCD */,
                                   0, /* use rcd_buf as data ara */
                                   device);
        if (IS_ERR(cqr)) {
                DBF_DEV_EVENT(DBF_WARNING, device, "%s",
                              "Could not allocate RCD request");
                ret = -ENOMEM;
                goto out_error;
        }
        dasd_eckd_fill_rcd_cqr(device, cqr, rcd_buf, lpm);
        cqr->callback = read_conf_cb;
        ret = dasd_sleep_on(cqr);
        /*
         * on success we update the user input parms
         */
        dasd_sfree_request(cqr, cqr->memdev);
        if (ret)
                goto out_error;

        *rcd_buffer_size = DASD_ECKD_RCD_DATA_SIZE;
        *rcd_buffer = rcd_buf;
        return 0;
out_error:
        kfree(rcd_buf);
        *rcd_buffer = NULL;
        *rcd_buffer_size = 0;
        return ret;
}

static int dasd_eckd_identify_conf_parts(struct dasd_eckd_private *private)
{

        struct dasd_sneq *sneq;
        int i, count;

        private->ned = NULL;
        private->sneq = NULL;
        private->vdsneq = NULL;
        private->gneq = NULL;
        count = private->conf_len / sizeof(struct dasd_sneq);
        sneq = (struct dasd_sneq *)private->conf_data;
        for (i = 0; i < count; ++i) {
                if (sneq->flags.identifier == 1 && sneq->format == 1)
                        private->sneq = sneq;
                else if (sneq->flags.identifier == 1 && sneq->format == 4)
                        private->vdsneq = (struct vd_sneq *)sneq;
                else if (sneq->flags.identifier == 2)
                        private->gneq = (struct dasd_gneq *)sneq;
                else if (sneq->flags.identifier == 3 && sneq->res1 == 1)
                        private->ned = (struct dasd_ned *)sneq;
                sneq++;
        }
        if (!private->ned || !private->gneq) {
                private->ned = NULL;
                private->sneq = NULL;
                private->vdsneq = NULL;
                private->gneq = NULL;
                return -EINVAL;
        }
        return 0;

};

static unsigned char dasd_eckd_path_access(void *conf_data, int conf_len)
{
        struct dasd_gneq *gneq;
        int i, count, found;

        count = conf_len / sizeof(*gneq);
        gneq = (struct dasd_gneq *)conf_data;
        found = 0;
        for (i = 0; i < count; ++i) {
                if (gneq->flags.identifier == 2) {
                        found = 1;
                        break;
                }
                gneq++;
        }
        if (found)
                return ((char *)gneq)[18] & 0x07;
        else
                return 0;
}

static int dasd_eckd_read_conf(struct dasd_device *device)
{
        void *conf_data;
        int conf_len, conf_data_saved;
        int rc;
        __u8 lpm, opm;
        struct dasd_eckd_private *private, path_private;
        struct dasd_path *path_data;
        struct dasd_uid *uid;
        char print_path_uid[60], print_device_uid[60];

        private = (struct dasd_eckd_private *) device->private;
        path_data = &device->path_data;
        opm = ccw_device_get_path_mask(device->cdev);
        conf_data_saved = 0;
        /* get configuration data per operational path */
        for (lpm = 0x80; lpm; lpm>>= 1) {
                if (!(lpm & opm))
                        continue;
                rc = dasd_eckd_read_conf_lpm(device, &conf_data,
                                             &conf_len, lpm);
                if (rc && rc != -EOPNOTSUPP) {  /* -EOPNOTSUPP is ok */
                        DBF_EVENT_DEVID(DBF_WARNING, device->cdev,
                                        "Read configuration data returned "
                                        "error %d", rc);
                        return rc;
                }
                if (conf_data == NULL) {
                        DBF_EVENT_DEVID(DBF_WARNING, device->cdev, "%s",
                                        "No configuration data "
                                        "retrieved");
                        /* no further analysis possible */
                        path_data->opm |= lpm;
                        continue;       /* no error */
                }
                /* save first valid configuration data */
                if (!conf_data_saved) {
                        kfree(private->conf_data);
                        private->conf_data = conf_data;
                        private->conf_len = conf_len;
                        if (dasd_eckd_identify_conf_parts(private)) {
                                private->conf_data = NULL;
                                private->conf_len = 0;
                                kfree(conf_data);
                                continue;
                        }
                        /*
                         * build device UID that other path data
                         * can be compared to it
                         */
                        dasd_eckd_generate_uid(device);
                        conf_data_saved++;
                } else {
                        path_private.conf_data = conf_data;
                        path_private.conf_len = DASD_ECKD_RCD_DATA_SIZE;
                        if (dasd_eckd_identify_conf_parts(
                                    &path_private)) {
                                path_private.conf_data = NULL;
                                path_private.conf_len = 0;
                                kfree(conf_data);
                                continue;
                        }

                        if (dasd_eckd_compare_path_uid(
                                    device, &path_private)) {
                                uid = &path_private.uid;
                                if (strlen(uid->vduit) > 0)
                                        snprintf(print_path_uid,
                                                 sizeof(print_path_uid),
                                                 "%s.%s.%04x.%02x.%s",
                                                 uid->vendor, uid->serial,
                                                 uid->ssid, uid->real_unit_addr,
                                                 uid->vduit);
                                else
                                        snprintf(print_path_uid,
                                                 sizeof(print_path_uid),
                                                 "%s.%s.%04x.%02x",
                                                 uid->vendor, uid->serial,
                                                 uid->ssid,
                                                 uid->real_unit_addr);
                                uid = &private->uid;
                                if (strlen(uid->vduit) > 0)
                                        snprintf(print_device_uid,
                                                 sizeof(print_device_uid),
                                                 "%s.%s.%04x.%02x.%s",
                                                 uid->vendor, uid->serial,
                                                 uid->ssid, uid->real_unit_addr,
                                                 uid->vduit);
                                else
                                        snprintf(print_device_uid,
                                                 sizeof(print_device_uid),
                                                 "%s.%s.%04x.%02x",
                                                 uid->vendor, uid->serial,
                                                 uid->ssid,
                                                 uid->real_unit_addr);
                                dev_err(&device->cdev->dev,
                                        "Not all channel paths lead to "
                                        "the same device, path %02X leads to "
                                        "device %s instead of %s\n", lpm,
                                        print_path_uid, print_device_uid);
                                return -EINVAL;
                        }

                        path_private.conf_data = NULL;
                        path_private.conf_len = 0;
                }
                switch (dasd_eckd_path_access(conf_data, conf_len)) {
                case 0x02:
                        path_data->npm |= lpm;
                        break;
                case 0x03:
                        path_data->ppm |= lpm;
                        break;
                }
                path_data->opm |= lpm;

                if (conf_data != private->conf_data)
                        kfree(conf_data);
        }

        return 0;
}

static int verify_fcx_max_data(struct dasd_device *device, __u8 lpm)
{
        struct dasd_eckd_private *private;
        int mdc;
        u32 fcx_max_data;

        private = (struct dasd_eckd_private *) device->private;
        if (private->fcx_max_data) {
                mdc = ccw_device_get_mdc(device->cdev, lpm);
                if ((mdc < 0)) {
                        dev_warn(&device->cdev->dev,
                                 "Detecting the maximum data size for zHPF "
                                 "requests failed (rc=%d) for a new path %x\n",
                                 mdc, lpm);
                        return mdc;
                }
                fcx_max_data = mdc * FCX_MAX_DATA_FACTOR;
                if (fcx_max_data < private->fcx_max_data) {
                        dev_warn(&device->cdev->dev,
                                 "The maximum data size for zHPF requests %u "
                                 "on a new path %x is below the active maximum "
                                 "%u\n", fcx_max_data, lpm,
                                 private->fcx_max_data);
                        return -EACCES;
                }
        }
        return 0;
}

static int rebuild_device_uid(struct dasd_device *device,
                              struct path_verification_work_data *data)
{
        struct dasd_eckd_private *private;
        struct dasd_path *path_data;
        __u8 lpm, opm;
        int rc;

        rc = -ENODEV;
        private = (struct dasd_eckd_private *) device->private;
        path_data = &device->path_data;
        opm = device->path_data.opm;

        for (lpm = 0x80; lpm; lpm >>= 1) {
                if (!(lpm & opm))
                        continue;
                memset(&data->rcd_buffer, 0, sizeof(data->rcd_buffer));
                memset(&data->cqr, 0, sizeof(data->cqr));
                data->cqr.cpaddr = &data->ccw;
                rc = dasd_eckd_read_conf_immediately(device, &data->cqr,
                                                     data->rcd_buffer,
                                                     lpm);

                if (rc) {
                        if (rc == -EOPNOTSUPP) /* -EOPNOTSUPP is ok */
                                continue;
                        DBF_EVENT_DEVID(DBF_WARNING, device->cdev,
                                        "Read configuration data "
                                        "returned error %d", rc);
                        break;
                }
                memcpy(private->conf_data, data->rcd_buffer,
                       DASD_ECKD_RCD_DATA_SIZE);
                if (dasd_eckd_identify_conf_parts(private)) {
                        rc = -ENODEV;
                } else /* first valid path is enough */
                        break;
        }

        if (!rc)
                rc = dasd_eckd_generate_uid(device);

        return rc;
}

static void do_path_verification_work(struct work_struct *work)
{
        struct path_verification_work_data *data;
        struct dasd_device *device;
        struct dasd_eckd_private path_private;
        struct dasd_uid *uid;
        __u8 path_rcd_buf[DASD_ECKD_RCD_DATA_SIZE];
        __u8 lpm, opm, npm, ppm, epm;
        unsigned long flags;
        char print_uid[60];
        int rc;

        data = container_of(work, struct path_verification_work_data, worker);
        device = data->device;

        /* delay path verification until device was resumed */
        if (test_bit(DASD_FLAG_SUSPENDED, &device->flags)) {
                schedule_work(work);
                return;
        }

        opm = 0;
        npm = 0;
        ppm = 0;
        epm = 0;
        for (lpm = 0x80; lpm; lpm >>= 1) {
                if (!(lpm & data->tbvpm))
                        continue;
                memset(&data->rcd_buffer, 0, sizeof(data->rcd_buffer));
                memset(&data->cqr, 0, sizeof(data->cqr));
                data->cqr.cpaddr = &data->ccw;
                rc = dasd_eckd_read_conf_immediately(device, &data->cqr,
                                                     data->rcd_buffer,
                                                     lpm);
                if (!rc) {
                        switch (dasd_eckd_path_access(data->rcd_buffer,
                                                      DASD_ECKD_RCD_DATA_SIZE)
                                ) {
                        case 0x02:
                                npm |= lpm;
                                break;
                        case 0x03:
                                ppm |= lpm;
                                break;
                        }
                        opm |= lpm;
                } else if (rc == -EOPNOTSUPP) {
                        DBF_EVENT_DEVID(DBF_WARNING, device->cdev, "%s",
                                        "path verification: No configuration "
                                        "data retrieved");
                        opm |= lpm;
                } else if (rc == -EAGAIN) {
                        DBF_EVENT_DEVID(DBF_WARNING, device->cdev, "%s",
                                        "path verification: device is stopped,"
                                        " try again later");
                        epm |= lpm;
                } else {
                        dev_warn(&device->cdev->dev,
                                 "Reading device feature codes failed "
                                 "(rc=%d) for new path %x\n", rc, lpm);
                        continue;
                }
                if (verify_fcx_max_data(device, lpm)) {
                        opm &= ~lpm;
                        npm &= ~lpm;
                        ppm &= ~lpm;
                        continue;
                }

                /*
                 * save conf_data for comparison after
                 * rebuild_device_uid may have changed
                 * the original data
                 */
                memcpy(&path_rcd_buf, data->rcd_buffer,
                       DASD_ECKD_RCD_DATA_SIZE);
                path_private.conf_data = (void *) &path_rcd_buf;
                path_private.conf_len = DASD_ECKD_RCD_DATA_SIZE;
                if (dasd_eckd_identify_conf_parts(&path_private)) {
                        path_private.conf_data = NULL;
                        path_private.conf_len = 0;
                        continue;
                }

                /*
                 * compare path UID with device UID only if at least
                 * one valid path is left
                 * in other case the device UID may have changed and
                 * the first working path UID will be used as device UID
                 */
                if (device->path_data.opm &&
                    dasd_eckd_compare_path_uid(device, &path_private)) {
                        /*
                         * the comparison was not successful
                         * rebuild the device UID with at least one
                         * known path in case a z/VM hyperswap command
                         * has changed the device
                         *
                         * after this compare again
                         *
                         * if either the rebuild or the recompare fails
                         * the path can not be used
                         */
                        if (rebuild_device_uid(device, data) ||
                            dasd_eckd_compare_path_uid(
                                    device, &path_private)) {
                                uid = &path_private.uid;
                                if (strlen(uid->vduit) > 0)
                                        snprintf(print_uid, sizeof(print_uid),
                                                 "%s.%s.%04x.%02x.%s",
                                                 uid->vendor, uid->serial,
                                                 uid->ssid, uid->real_unit_addr,
                                                 uid->vduit);
                                else
                                        snprintf(print_uid, sizeof(print_uid),
                                                 "%s.%s.%04x.%02x",
                                                 uid->vendor, uid->serial,
                                                 uid->ssid,
                                                 uid->real_unit_addr);
                                dev_err(&device->cdev->dev,
                                        "The newly added channel path %02X "
                                        "will not be used because it leads "
                                        "to a different device %s\n",
                                        lpm, print_uid);
                                opm &= ~lpm;
                                npm &= ~lpm;
                                ppm &= ~lpm;
                                continue;
                        }
                }

                /*
                 * There is a small chance that a path is lost again between
                 * above path verification and the following modification of
                 * the device opm mask. We could avoid that race here by using
                 * yet another path mask, but we rather deal with this unlikely
                 * situation in dasd_start_IO.
                 */
                spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
                if (!device->path_data.opm && opm) {
                        device->path_data.opm = opm;
                        dasd_generic_path_operational(device);
                } else
                        device->path_data.opm |= opm;
                device->path_data.npm |= npm;
                device->path_data.ppm |= ppm;
                device->path_data.tbvpm |= epm;
                spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
        }

        dasd_put_device(device);
        if (data->isglobal)
                mutex_unlock(&dasd_path_verification_mutex);
        else
                kfree(data);
}

static int dasd_eckd_verify_path(struct dasd_device *device, __u8 lpm)
{
        struct path_verification_work_data *data;

        data = kmalloc(sizeof(*data), GFP_ATOMIC | GFP_DMA);
        if (!data) {
                if (mutex_trylock(&dasd_path_verification_mutex)) {
                        data = path_verification_worker;
                        data->isglobal = 1;
                } else
                        return -ENOMEM;
        } else {
                memset(data, 0, sizeof(*data));
                data->isglobal = 0;
        }
        INIT_WORK(&data->worker, do_path_verification_work);
        dasd_get_device(device);
        data->device = device;
        data->tbvpm = lpm;
        schedule_work(&data->worker);
        return 0;
}

static int dasd_eckd_read_features(struct dasd_device *device)
{
        struct dasd_psf_prssd_data *prssdp;
        struct dasd_rssd_features *features;
        struct dasd_ccw_req *cqr;
        struct ccw1 *ccw;
        int rc;
        struct dasd_eckd_private *private;

        private = (struct dasd_eckd_private *) device->private;
        memset(&private->features, 0, sizeof(struct dasd_rssd_features));
        cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 1 /* PSF */ + 1 /* RSSD */,
                                   (sizeof(struct dasd_psf_prssd_data) +
                                    sizeof(struct dasd_rssd_features)),
                                   device);
        if (IS_ERR(cqr)) {
                DBF_EVENT_DEVID(DBF_WARNING, device->cdev, "%s", "Could not "
                                "allocate initialization request");
                return PTR_ERR(cqr);
        }
        cqr->startdev = device;
        cqr->memdev = device;
        cqr->block = NULL;
        cqr->retries = 256;
        cqr->expires = 10 * HZ;

        /* Prepare for Read Subsystem Data */
        prssdp = (struct dasd_psf_prssd_data *) cqr->data;
        memset(prssdp, 0, sizeof(struct dasd_psf_prssd_data));
        prssdp->order = PSF_ORDER_PRSSD;
        prssdp->suborder = 0x41;        /* Read Feature Codes */
        /* all other bytes of prssdp must be zero */

        ccw = cqr->cpaddr;
        ccw->cmd_code = DASD_ECKD_CCW_PSF;
        ccw->count = sizeof(struct dasd_psf_prssd_data);
        ccw->flags |= CCW_FLAG_CC;
        ccw->cda = (__u32)(addr_t) prssdp;

        /* Read Subsystem Data - feature codes */
        features = (struct dasd_rssd_features *) (prssdp + 1);
        memset(features, 0, sizeof(struct dasd_rssd_features));

        ccw++;
        ccw->cmd_code = DASD_ECKD_CCW_RSSD;
        ccw->count = sizeof(struct dasd_rssd_features);
        ccw->cda = (__u32)(addr_t) features;

        cqr->buildclk = get_clock();
        cqr->status = DASD_CQR_FILLED;
        rc = dasd_sleep_on(cqr);
        if (rc == 0) {
                prssdp = (struct dasd_psf_prssd_data *) cqr->data;
                features = (struct dasd_rssd_features *) (prssdp + 1);
                memcpy(&private->features, features,
                       sizeof(struct dasd_rssd_features));
        } else
                dev_warn(&device->cdev->dev, "Reading device feature codes"
                         " failed with rc=%d\n", rc);
        dasd_sfree_request(cqr, cqr->memdev);
        return rc;
}


/*
 * Build CP for Perform Subsystem Function - SSC.
 */
static struct dasd_ccw_req *dasd_eckd_build_psf_ssc(struct dasd_device *device,
                                                    int enable_pav)
{
        struct dasd_ccw_req *cqr;
        struct dasd_psf_ssc_data *psf_ssc_data;
        struct ccw1 *ccw;

        cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 1 /* PSF */ ,
                                  sizeof(struct dasd_psf_ssc_data),
                                  device);

        if (IS_ERR(cqr)) {
                DBF_DEV_EVENT(DBF_WARNING, device, "%s",
                           "Could not allocate PSF-SSC request");
                return cqr;
        }
        psf_ssc_data = (struct dasd_psf_ssc_data *)cqr->data;
        psf_ssc_data->order = PSF_ORDER_SSC;
        psf_ssc_data->suborder = 0xc0;
        if (enable_pav) {
                psf_ssc_data->suborder |= 0x08;
                psf_ssc_data->reserved[0] = 0x88;
        }
        ccw = cqr->cpaddr;
        ccw->cmd_code = DASD_ECKD_CCW_PSF;
        ccw->cda = (__u32)(addr_t)psf_ssc_data;
        ccw->count = 66;

        cqr->startdev = device;
        cqr->memdev = device;
        cqr->block = NULL;
        cqr->retries = 256;
        cqr->expires = 10*HZ;
        cqr->buildclk = get_clock();
        cqr->status = DASD_CQR_FILLED;
        return cqr;
}

/*
 * Perform Subsystem Function.
 * It is necessary to trigger CIO for channel revalidation since this
 * call might change behaviour of DASD devices.
 */
static int
dasd_eckd_psf_ssc(struct dasd_device *device, int enable_pav)
{
        struct dasd_ccw_req *cqr;
        int rc;

        cqr = dasd_eckd_build_psf_ssc(device, enable_pav);
        if (IS_ERR(cqr))
                return PTR_ERR(cqr);

        rc = dasd_sleep_on(cqr);
        if (!rc)
                /* trigger CIO to reprobe devices */
                css_schedule_reprobe();
        dasd_sfree_request(cqr, cqr->memdev);
        return rc;
}

/*
 * Valide storage server of current device.
 */
static void dasd_eckd_validate_server(struct dasd_device *device)
{
        int rc;
        struct dasd_eckd_private *private;
        int enable_pav;

        private = (struct dasd_eckd_private *) device->private;
        if (private->uid.type == UA_BASE_PAV_ALIAS ||
            private->uid.type == UA_HYPER_PAV_ALIAS)
                return;
        if (dasd_nopav || MACHINE_IS_VM)
                enable_pav = 0;
        else
                enable_pav = 1;
        rc = dasd_eckd_psf_ssc(device, enable_pav);

        /* may be requested feature is not available on server,
         * therefore just report error and go ahead */
        DBF_EVENT_DEVID(DBF_WARNING, device->cdev, "PSF-SSC for SSID %04x "
                        "returned rc=%d", private->uid.ssid, rc);
}

/*
 * worker to do a validate server in case of a lost pathgroup
 */
static void dasd_eckd_do_validate_server(struct work_struct *work)
{
        struct dasd_device *device = container_of(work, struct dasd_device,
                                                  kick_validate);
        dasd_eckd_validate_server(device);
        dasd_put_device(device);
}

static void dasd_eckd_kick_validate_server(struct dasd_device *device)
{
        dasd_get_device(device);
        /* exit if device not online or in offline processing */
        if (test_bit(DASD_FLAG_OFFLINE, &device->flags) ||
           device->state < DASD_STATE_ONLINE) {
                dasd_put_device(device);
                return;
        }
        /* queue call to do_validate_server to the kernel event daemon. */
        schedule_work(&device->kick_validate);
}

static u32 get_fcx_max_data(struct dasd_device *device)
{
#if defined(CONFIG_64BIT)
        int tpm, mdc;
        int fcx_in_css, fcx_in_gneq, fcx_in_features;
        struct dasd_eckd_private *private;

        if (dasd_nofcx)
                return 0;
        /* is transport mode supported? */
        private = (struct dasd_eckd_private *) device->private;
        fcx_in_css = css_general_characteristics.fcx;
        fcx_in_gneq = private->gneq->reserved2[7] & 0x04;
        fcx_in_features = private->features.feature[40] & 0x80;
        tpm = fcx_in_css && fcx_in_gneq && fcx_in_features;

        if (!tpm)
                return 0;

        mdc = ccw_device_get_mdc(device->cdev, 0);
        if (mdc < 0) {
                dev_warn(&device->cdev->dev, "Detecting the maximum supported"
                         " data size for zHPF requests failed\n");
                return 0;
        } else
                return mdc * FCX_MAX_DATA_FACTOR;
#else
        return 0;
#endif
}

/*
 * Check device characteristics.
 * If the device is accessible using ECKD discipline, the device is enabled.
 */
static int
dasd_eckd_check_characteristics(struct dasd_device *device)
{
        struct dasd_eckd_private *private;
        struct dasd_block *block;
        struct dasd_uid temp_uid;
        int rc, i;
        int readonly;
        unsigned long value;

        /* setup work queue for validate server*/
        INIT_WORK(&device->kick_validate, dasd_eckd_do_validate_server);

        if (!ccw_device_is_pathgroup(device->cdev)) {
                dev_warn(&device->cdev->dev,
                         "A channel path group could not be established\n");
                return -EIO;
        }
        if (!ccw_device_is_multipath(device->cdev)) {
                dev_info(&device->cdev->dev,
                         "The DASD is not operating in multipath mode\n");
        }
        private = (struct dasd_eckd_private *) device->private;
        if (!private) {
                private = kzalloc(sizeof(*private), GFP_KERNEL | GFP_DMA);
                if (!private) {
                        dev_warn(&device->cdev->dev,
                                 "Allocating memory for private DASD data "
                                 "failed\n");
                        return -ENOMEM;
                }
                device->private = (void *) private;
        } else {
                memset(private, 0, sizeof(*private));
        }
        /* Invalidate status of initial analysis. */
        private->init_cqr_status = -1;
        /* Set default cache operations. */
        private->attrib.operation = DASD_NORMAL_CACHE;
        private->attrib.nr_cyl = 0;

        /* Read Configuration Data */
        rc = dasd_eckd_read_conf(device);
        if (rc)
                goto out_err1;

        /* set default timeout */
        device->default_expires = DASD_EXPIRES;
        if (private->gneq) {
                value = 1;
                for (i = 0; i < private->gneq->timeout.value; i++)
                        value = 10 * value;
                value = value * private->gneq->timeout.number;
                /* do not accept useless values */
                if (value != 0 && value <= DASD_EXPIRES_MAX)
                        device->default_expires = value;
        }

        dasd_eckd_get_uid(device, &temp_uid);
        if (temp_uid.type == UA_BASE_DEVICE) {
                block = dasd_alloc_block();
                if (IS_ERR(block)) {
                        DBF_EVENT_DEVID(DBF_WARNING, device->cdev, "%s",
                                        "could not allocate dasd "
                                        "block structure");
                        rc = PTR_ERR(block);
                        goto out_err1;
                }
                device->block = block;
                block->base = device;
        }

        /* register lcu with alias handling, enable PAV */
        rc = dasd_alias_make_device_known_to_lcu(device);
        if (rc)
                goto out_err2;

        dasd_eckd_validate_server(device);

        /* device may report different configuration data after LCU setup */
        rc = dasd_eckd_read_conf(device);
        if (rc)
                goto out_err3;

        /* Read Feature Codes */
        dasd_eckd_read_features(device);

        /* Read Device Characteristics */
        rc = dasd_generic_read_dev_chars(device, DASD_ECKD_MAGIC,
                                         &private->rdc_data, 64);
        if (rc) {
                DBF_EVENT_DEVID(DBF_WARNING, device->cdev,
                                "Read device characteristic failed, rc=%d", rc);
                goto out_err3;
        }

        if ((device->features & DASD_FEATURE_USERAW) &&
            !(private->rdc_data.facilities.RT_in_LR)) {
                dev_err(&device->cdev->dev, "The storage server does not "
                        "support raw-track access\n");
                rc = -EINVAL;
                goto out_err3;
        }

        /* find the valid cylinder size */
        if (private->rdc_data.no_cyl == LV_COMPAT_CYL &&
            private->rdc_data.long_no_cyl)
                private->real_cyl = private->rdc_data.long_no_cyl;
        else
                private->real_cyl = private->rdc_data.no_cyl;

        private->fcx_max_data = get_fcx_max_data(device);

        readonly = dasd_device_is_ro(device);
        if (readonly)
                set_bit(DASD_FLAG_DEVICE_RO, &device->flags);

        dev_info(&device->cdev->dev, "New DASD %04X/%02X (CU %04X/%02X) "
                 "with %d cylinders, %d heads, %d sectors%s\n",
                 private->rdc_data.dev_type,
                 private->rdc_data.dev_model,
                 private->rdc_data.cu_type,
                 private->rdc_data.cu_model.model,
                 private->real_cyl,
                 private->rdc_data.trk_per_cyl,
                 private->rdc_data.sec_per_trk,
                 readonly ? ", read-only device" : "");
        return 0;

out_err3:
        dasd_alias_disconnect_device_from_lcu(device);
out_err2:
        dasd_free_block(device->block);
        device->block = NULL;
out_err1:
        kfree(private->conf_data);
        kfree(device->private);
        device->private = NULL;
        return rc;
}

static void dasd_eckd_uncheck_device(struct dasd_device *device)
{
        struct dasd_eckd_private *private;

        private = (struct dasd_eckd_private *) device->private;
        dasd_alias_disconnect_device_from_lcu(device);
        private->ned = NULL;
        private->sneq = NULL;
        private->vdsneq = NULL;
        private->gneq = NULL;
        private->conf_len = 0;
        kfree(private->conf_data);
        private->conf_data = NULL;
}

static struct dasd_ccw_req *
dasd_eckd_analysis_ccw(struct dasd_device *device)
{
        struct dasd_eckd_private *private;
        struct eckd_count *count_data;
        struct LO_eckd_data *LO_data;
        struct dasd_ccw_req *cqr;
        struct ccw1 *ccw;
        int cplength, datasize;
        int i;

        private = (struct dasd_eckd_private *) device->private;

        cplength = 8;
        datasize = sizeof(struct DE_eckd_data) + 2*sizeof(struct LO_eckd_data);
        cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, cplength, datasize, device);
        if (IS_ERR(cqr))
                return cqr;
        ccw = cqr->cpaddr;
        /* Define extent for the first 3 tracks. */
        define_extent(ccw++, cqr->data, 0, 2,
                      DASD_ECKD_CCW_READ_COUNT, device);
        LO_data = cqr->data + sizeof(struct DE_eckd_data);
        /* Locate record for the first 4 records on track 0. */
        ccw[-1].flags |= CCW_FLAG_CC;
        locate_record(ccw++, LO_data++, 0, 0, 4,
                      DASD_ECKD_CCW_READ_COUNT, device, 0);

        count_data = private->count_area;
        for (i = 0; i < 4; i++) {
                ccw[-1].flags |= CCW_FLAG_CC;
                ccw->cmd_code = DASD_ECKD_CCW_READ_COUNT;
                ccw->flags = 0;
                ccw->count = 8;
                ccw->cda = (__u32)(addr_t) count_data;
                ccw++;
                count_data++;
        }

        /* Locate record for the first record on track 2. */
        ccw[-1].flags |= CCW_FLAG_CC;
        locate_record(ccw++, LO_data++, 2, 0, 1,
                      DASD_ECKD_CCW_READ_COUNT, device, 0);
        /* Read count ccw. */
        ccw[-1].flags |= CCW_FLAG_CC;
        ccw->cmd_code = DASD_ECKD_CCW_READ_COUNT;
        ccw->flags = 0;
        ccw->count = 8;
        ccw->cda = (__u32)(addr_t) count_data;

        cqr->block = NULL;
        cqr->startdev = device;
        cqr->memdev = device;
        cqr->retries = 255;
        cqr->buildclk = get_clock();
        cqr->status = DASD_CQR_FILLED;
        return cqr;
}

/* differentiate between 'no record found' and any other error */
static int dasd_eckd_analysis_evaluation(struct dasd_ccw_req *init_cqr)
{
        char *sense;
        if (init_cqr->status == DASD_CQR_DONE)
                return INIT_CQR_OK;
        else if (init_cqr->status == DASD_CQR_NEED_ERP ||
                 init_cqr->status == DASD_CQR_FAILED) {
                sense = dasd_get_sense(&init_cqr->irb);
                if (sense && (sense[1] & SNS1_NO_REC_FOUND))
                        return INIT_CQR_UNFORMATTED;
                else
                        return INIT_CQR_ERROR;
        } else
                return INIT_CQR_ERROR;
}

/*
 * This is the callback function for the init_analysis cqr. It saves
 * the status of the initial analysis ccw before it frees it and kicks
 * the device to continue the startup sequence. This will call
 * dasd_eckd_do_analysis again (if the devices has not been marked
 * for deletion in the meantime).
 */
static void dasd_eckd_analysis_callback(struct dasd_ccw_req *init_cqr,
                                        void *data)
{
        struct dasd_eckd_private *private;
        struct dasd_device *device;

        device = init_cqr->startdev;
        private = (struct dasd_eckd_private *) device->private;
        private->init_cqr_status = dasd_eckd_analysis_evaluation(init_cqr);
        dasd_sfree_request(init_cqr, device);
        dasd_kick_device(device);
}

static int dasd_eckd_start_analysis(struct dasd_block *block)
{
        struct dasd_ccw_req *init_cqr;

        init_cqr = dasd_eckd_analysis_ccw(block->base);
        if (IS_ERR(init_cqr))
                return PTR_ERR(init_cqr);
        init_cqr->callback = dasd_eckd_analysis_callback;
        init_cqr->callback_data = NULL;
        init_cqr->expires = 5*HZ;
        /* first try without ERP, so we can later handle unformatted
         * devices as special case
         */
        clear_bit(DASD_CQR_FLAGS_USE_ERP, &init_cqr->flags);
        init_cqr->retries = 0;
        dasd_add_request_head(init_cqr);
        return -EAGAIN;
}

static int dasd_eckd_end_analysis(struct dasd_block *block)
{
        struct dasd_device *device;
        struct dasd_eckd_private *private;
        struct eckd_count *count_area;
        unsigned int sb, blk_per_trk;
        int status, i;
        struct dasd_ccw_req *init_cqr;

        device = block->base;
        private = (struct dasd_eckd_private *) device->private;
        status = private->init_cqr_status;
        private->init_cqr_status = -1;
        if (status == INIT_CQR_ERROR) {
                /* try again, this time with full ERP */
                init_cqr = dasd_eckd_analysis_ccw(device);
                dasd_sleep_on(init_cqr);
                status = dasd_eckd_analysis_evaluation(init_cqr);
                dasd_sfree_request(init_cqr, device);
        }

        if (device->features & DASD_FEATURE_USERAW) {
                block->bp_block = DASD_RAW_BLOCKSIZE;
                blk_per_trk = DASD_RAW_BLOCK_PER_TRACK;
                block->s2b_shift = 3;
                goto raw;
        }

        if (status == INIT_CQR_UNFORMATTED) {
                dev_warn(&device->cdev->dev, "The DASD is not formatted\n");
                return -EMEDIUMTYPE;
        } else if (status == INIT_CQR_ERROR) {
                dev_err(&device->cdev->dev,
                        "Detecting the DASD disk layout failed because "
                        "of an I/O error\n");
                return -EIO;
        }

        private->uses_cdl = 1;
        /* Check Track 0 for Compatible Disk Layout */
        count_area = NULL;
        for (i = 0; i < 3; i++) {
                if (private->count_area[i].kl != 4 ||
                    private->count_area[i].dl != dasd_eckd_cdl_reclen(i) - 4) {
                        private->uses_cdl = 0;
                        break;
                }
        }
        if (i == 3)
                count_area = &private->count_area[4];

        if (private->uses_cdl == 0) {
                for (i = 0; i < 5; i++) {
                        if ((private->count_area[i].kl != 0) ||
                            (private->count_area[i].dl !=
                             private->count_area[0].dl))
                                break;
                }
                if (i == 5)
                        count_area = &private->count_area[0];
        } else {
                if (private->count_area[3].record == 1)
                        dev_warn(&device->cdev->dev,
                                 "Track 0 has no records following the VTOC\n");
        }

        if (count_area != NULL && count_area->kl == 0) {
                /* we found notthing violating our disk layout */
                if (dasd_check_blocksize(count_area->dl) == 0)
                        block->bp_block = count_area->dl;
        }
        if (block->bp_block == 0) {
                dev_warn(&device->cdev->dev,
                         "The disk layout of the DASD is not supported\n");
                return -EMEDIUMTYPE;
        }
        block->s2b_shift = 0;   /* bits to shift 512 to get a block */
        for (sb = 512; sb < block->bp_block; sb = sb << 1)
                block->s2b_shift++;

        blk_per_trk = recs_per_track(&private->rdc_data, 0, block->bp_block);

raw:
        block->blocks = (private->real_cyl *
                          private->rdc_data.trk_per_cyl *
                          blk_per_trk);

        dev_info(&device->cdev->dev,
                 "DASD with %d KB/block, %d KB total size, %d KB/track, "
                 "%s\n", (block->bp_block >> 10),
                 ((private->real_cyl *
                   private->rdc_data.trk_per_cyl *
                   blk_per_trk * (block->bp_block >> 9)) >> 1),
                 ((blk_per_trk * block->bp_block) >> 10),
                 private->uses_cdl ?
                 "compatible disk layout" : "linux disk layout");

        return 0;
}

static int dasd_eckd_do_analysis(struct dasd_block *block)
{
        struct dasd_eckd_private *private;

        private = (struct dasd_eckd_private *) block->base->private;
        if (private->init_cqr_status < 0)
                return dasd_eckd_start_analysis(block);
        else
                return dasd_eckd_end_analysis(block);
}

static int dasd_eckd_ready_to_online(struct dasd_device *device)
{
        return dasd_alias_add_device(device);
};

static int dasd_eckd_online_to_ready(struct dasd_device *device)
{

        cancel_work_sync(&device->reload_device);
        cancel_work_sync(&device->kick_validate);
        return dasd_alias_remove_device(device);
};

static int
dasd_eckd_fill_geometry(struct dasd_block *block, struct hd_geometry *geo)
{
        struct dasd_eckd_private *private;

        private = (struct dasd_eckd_private *) block->base->private;
        if (dasd_check_blocksize(block->bp_block) == 0) {
                geo->sectors = recs_per_track(&private->rdc_data,
                                              0, block->bp_block);
        }
        geo->cylinders = private->rdc_data.no_cyl;
        geo->heads = private->rdc_data.trk_per_cyl;
        return 0;
}

static struct dasd_ccw_req *
dasd_eckd_format_device(struct dasd_device * device,
                        struct format_data_t * fdata)
{
        struct dasd_eckd_private *private;
        struct dasd_ccw_req *fcp;
        struct eckd_count *ect;
        struct ccw1 *ccw;
        void *data;
        int rpt;
        struct ch_t address;
        int cplength, datasize;
        int i;
        int intensity = 0;
        int r0_perm;

        private = (struct dasd_eckd_private *) device->private;
        rpt = recs_per_track(&private->rdc_data, 0, fdata->blksize);
        set_ch_t(&address,
                 fdata->start_unit / private->rdc_data.trk_per_cyl,
                 fdata->start_unit % private->rdc_data.trk_per_cyl);

        /* Sanity checks. */
        if (fdata->start_unit >=
            (private->real_cyl * private->rdc_data.trk_per_cyl)) {
                dev_warn(&device->cdev->dev, "Start track number %d used in "
                         "formatting is too big\n", fdata->start_unit);
                return ERR_PTR(-EINVAL);
        }
        if (fdata->start_unit > fdata->stop_unit) {
                dev_warn(&device->cdev->dev, "Start track %d used in "
                         "formatting exceeds end track\n", fdata->start_unit);
                return ERR_PTR(-EINVAL);
        }
        if (dasd_check_blocksize(fdata->blksize) != 0) {
                dev_warn(&device->cdev->dev,
                         "The DASD cannot be formatted with block size %d\n",
                         fdata->blksize);
                return ERR_PTR(-EINVAL);
        }

        /*
         * fdata->intensity is a bit string that tells us what to do:
         *   Bit 0: write record zero
         *   Bit 1: write home address, currently not supported
         *   Bit 2: invalidate tracks
         *   Bit 3: use OS/390 compatible disk layout (cdl)
         *   Bit 4: do not allow storage subsystem to modify record zero
         * Only some bit combinations do make sense.
         */
        if (fdata->intensity & 0x10) {
                r0_perm = 0;
                intensity = fdata->intensity & ~0x10;
        } else {
                r0_perm = 1;
                intensity = fdata->intensity;
        }
        switch (intensity) {
        case 0x00:      /* Normal format */
        case 0x08:      /* Normal format, use cdl. */
                cplength = 2 + rpt;
                datasize = sizeof(struct DE_eckd_data) +
                        sizeof(struct LO_eckd_data) +
                        rpt * sizeof(struct eckd_count);
                break;
        case 0x01:      /* Write record zero and format track. */
        case 0x09:      /* Write record zero and format track, use cdl. */
                cplength = 3 + rpt;
                datasize = sizeof(struct DE_eckd_data) +
                        sizeof(struct LO_eckd_data) +
                        sizeof(struct eckd_count) +
                        rpt * sizeof(struct eckd_count);
                break;
        case 0x04:      /* Invalidate track. */
        case 0x0c:      /* Invalidate track, use cdl. */
                cplength = 3;
                datasize = sizeof(struct DE_eckd_data) +
                        sizeof(struct LO_eckd_data) +
                        sizeof(struct eckd_count);
                break;
        default:
                dev_warn(&device->cdev->dev, "An I/O control call used "
                         "incorrect flags 0x%x\n", fdata->intensity);
                return ERR_PTR(-EINVAL);
        }
        /* Allocate the format ccw request. */
        fcp = dasd_smalloc_request(DASD_ECKD_MAGIC, cplength, datasize, device);
        if (IS_ERR(fcp))
                return fcp;

        data = fcp->data;
        ccw = fcp->cpaddr;

        switch (intensity & ~0x08) {
        case 0x00: /* Normal format. */
                define_extent(ccw++, (struct DE_eckd_data *) data,
                              fdata->start_unit, fdata->start_unit,
                              DASD_ECKD_CCW_WRITE_CKD, device);
                /* grant subsystem permission to format R0 */
                if (r0_perm)
                        ((struct DE_eckd_data *)data)->ga_extended |= 0x04;
                data += sizeof(struct DE_eckd_data);
                ccw[-1].flags |= CCW_FLAG_CC;
                locate_record(ccw++, (struct LO_eckd_data *) data,
                              fdata->start_unit, 0, rpt,
                              DASD_ECKD_CCW_WRITE_CKD, device,
                              fdata->blksize);
                data += sizeof(struct LO_eckd_data);
                break;
        case 0x01: /* Write record zero + format track. */
                define_extent(ccw++, (struct DE_eckd_data *) data,
                              fdata->start_unit, fdata->start_unit,
                              DASD_ECKD_CCW_WRITE_RECORD_ZERO,
                              device);
                data += sizeof(struct DE_eckd_data);
                ccw[-1].flags |= CCW_FLAG_CC;
                locate_record(ccw++, (struct LO_eckd_data *) data,
                              fdata->start_unit, 0, rpt + 1,
                              DASD_ECKD_CCW_WRITE_RECORD_ZERO, device,
                              device->block->bp_block);
                data += sizeof(struct LO_eckd_data);
                break;
        case 0x04: /* Invalidate track. */
                define_extent(ccw++, (struct DE_eckd_data *) data,
                              fdata->start_unit, fdata->start_unit,
                              DASD_ECKD_CCW_WRITE_CKD, device);
                data += sizeof(struct DE_eckd_data);
                ccw[-1].flags |= CCW_FLAG_CC;
                locate_record(ccw++, (struct LO_eckd_data *) data,
                              fdata->start_unit, 0, 1,
                              DASD_ECKD_CCW_WRITE_CKD, device, 8);
                data += sizeof(struct LO_eckd_data);
                break;
        }
        if (intensity & 0x01) { /* write record zero */
                ect = (struct eckd_count *) data;
                data += sizeof(struct eckd_count);
                ect->cyl = address.cyl;
                ect->head = address.head;
                ect->record = 0;
                ect->kl = 0;
                ect->dl = 8;
                ccw[-1].flags |= CCW_FLAG_CC;
                ccw->cmd_code = DASD_ECKD_CCW_WRITE_RECORD_ZERO;
                ccw->flags = CCW_FLAG_SLI;
                ccw->count = 8;
                ccw->cda = (__u32)(addr_t) ect;
                ccw++;
        }
        if ((intensity & ~0x08) & 0x04) {       /* erase track */
                ect = (struct eckd_count *) data;
                data += sizeof(struct eckd_count);
                ect->cyl = address.cyl;
                ect->head = address.head;
                ect->record = 1;
                ect->kl = 0;
                ect->dl = 0;
                ccw[-1].flags |= CCW_FLAG_CC;
                ccw->cmd_code = DASD_ECKD_CCW_WRITE_CKD;
                ccw->flags = CCW_FLAG_SLI;
                ccw->count = 8;
                ccw->cda = (__u32)(addr_t) ect;
        } else {                /* write remaining records */
                for (i = 0; i < rpt; i++) {
                        ect = (struct eckd_count *) data;
                        data += sizeof(struct eckd_count);
                        ect->cyl = address.cyl;
                        ect->head = address.head;
                        ect->record = i + 1;
                        ect->kl = 0;
                        ect->dl = fdata->blksize;
                        /* Check for special tracks 0-1 when formatting CDL */
                        if ((intensity & 0x08) &&
                            fdata->start_unit == 0) {
                                if (i < 3) {
                                        ect->kl = 4;
                                        ect->dl = sizes_trk0[i] - 4;
                                }
                        }
                        if ((intensity & 0x08) &&
                            fdata->start_unit == 1) {
                                ect->kl = 44;
                                ect->dl = LABEL_SIZE - 44;
                        }
                        ccw[-1].flags |= CCW_FLAG_CC;
                        ccw->cmd_code = DASD_ECKD_CCW_WRITE_CKD;
                        ccw->flags = CCW_FLAG_SLI;
                        ccw->count = 8;
                        ccw->cda = (__u32)(addr_t) ect;
                        ccw++;
                }
        }
        fcp->startdev = device;
        fcp->memdev = device;
        fcp->retries = 256;
        fcp->buildclk = get_clock();
        fcp->status = DASD_CQR_FILLED;
        return fcp;
}

static void dasd_eckd_handle_terminated_request(struct dasd_ccw_req *cqr)
{
        cqr->status = DASD_CQR_FILLED;
        if (cqr->block && (cqr->startdev != cqr->block->base)) {
                dasd_eckd_reset_ccw_to_base_io(cqr);
                cqr->startdev = cqr->block->base;
                cqr->lpm = cqr->block->base->path_data.opm;
        }
};

static dasd_erp_fn_t
dasd_eckd_erp_action(struct dasd_ccw_req * cqr)
{
        struct dasd_device *device = (struct dasd_device *) cqr->startdev;
        struct ccw_device *cdev = device->cdev;

        switch (cdev->id.cu_type) {
        case 0x3990:
        case 0x2105:
        case 0x2107:
        case 0x1750:
                return dasd_3990_erp_action;
        case 0x9343:
        case 0x3880:
        default:
                return dasd_default_erp_action;
        }
}

static dasd_erp_fn_t
dasd_eckd_erp_postaction(struct dasd_ccw_req * cqr)
{
        return dasd_default_erp_postaction;
}

static void dasd_eckd_check_for_device_change(struct dasd_device *device,
                                              struct dasd_ccw_req *cqr,
                                              struct irb *irb)
{
        char mask;
        char *sense = NULL;
        struct dasd_eckd_private *private;

        private = (struct dasd_eckd_private *) device->private;
        /* first of all check for state change pending interrupt */
        mask = DEV_STAT_ATTENTION | DEV_STAT_DEV_END | DEV_STAT_UNIT_EXCEP;
        if ((scsw_dstat(&irb->scsw) & mask) == mask) {
                /*
                 * for alias only, not in offline processing
                 * and only if not suspended
                 */
                if (!device->block && private->lcu &&
                    device->state == DASD_STATE_ONLINE &&
                    !test_bit(DASD_FLAG_OFFLINE, &device->flags) &&
                    !test_bit(DASD_FLAG_SUSPENDED, &device->flags)) {
                        /*
                         * the state change could be caused by an alias
                         * reassignment remove device from alias handling
                         * to prevent new requests from being scheduled on
                         * the wrong alias device
                         */
                        dasd_alias_remove_device(device);

                        /* schedule worker to reload device */
                        dasd_reload_device(device);
                }
                dasd_generic_handle_state_change(device);
                return;
        }

        sense = dasd_get_sense(irb);
        if (!sense)
                return;

        /* summary unit check */
        if ((sense[27] & DASD_SENSE_BIT_0) && (sense[7] == 0x0D) &&
            (scsw_dstat(&irb->scsw) & DEV_STAT_UNIT_CHECK)) {
                dasd_alias_handle_summary_unit_check(device, irb);
                return;
        }

        /* service information message SIM */
        if (!cqr && !(sense[27] & DASD_SENSE_BIT_0) &&
            ((sense[6] & DASD_SIM_SENSE) == DASD_SIM_SENSE)) {
                dasd_3990_erp_handle_sim(device, sense);
                return;
        }

        /* loss of device reservation is handled via base devices only
         * as alias devices may be used with several bases
         */
        if (device->block && (sense[27] & DASD_SENSE_BIT_0) &&
            (sense[7] == 0x3F) &&
            (scsw_dstat(&irb->scsw) & DEV_STAT_UNIT_CHECK) &&
            test_bit(DASD_FLAG_IS_RESERVED, &device->flags)) {
                if (device->features & DASD_FEATURE_FAILONSLCK)
                        set_bit(DASD_FLAG_LOCK_STOLEN, &device->flags);
                clear_bit(DASD_FLAG_IS_RESERVED, &device->flags);
                dev_err(&device->cdev->dev,
                        "The device reservation was lost\n");
        }
}

static struct dasd_ccw_req *dasd_eckd_build_cp_cmd_single(
                                               struct dasd_device *startdev,
                                               struct dasd_block *block,
                                               struct request *req,
                                               sector_t first_rec,
                                               sector_t last_rec,
                                               sector_t first_trk,
                                               sector_t last_trk,
                                               unsigned int first_offs,
                                               unsigned int last_offs,
                                               unsigned int blk_per_trk,
                                               unsigned int blksize)
{
        struct dasd_eckd_private *private;
        unsigned long *idaws;
        struct LO_eckd_data *LO_data;
        struct dasd_ccw_req *cqr;
        struct ccw1 *ccw;
        struct req_iterator iter;
        struct bio_vec *bv;
        char *dst;
        unsigned int off;
        int count, cidaw, cplength, datasize;
        sector_t recid;
        unsigned char cmd, rcmd;
        int use_prefix;
        struct dasd_device *basedev;

        basedev = block->base;
        private = (struct dasd_eckd_private *) basedev->private;
        if (rq_data_dir(req) == READ)
                cmd = DASD_ECKD_CCW_READ_MT;
        else if (rq_data_dir(req) == WRITE)
                cmd = DASD_ECKD_CCW_WRITE_MT;
        else
                return ERR_PTR(-EINVAL);

        /* Check struct bio and count the number of blocks for the request. */
        count = 0;
        cidaw = 0;
        rq_for_each_segment(bv, req, iter) {
                if (bv->bv_len & (blksize - 1))
                        /* Eckd can only do full blocks. */
                        return ERR_PTR(-EINVAL);
                count += bv->bv_len >> (block->s2b_shift + 9);
#if defined(CONFIG_64BIT)
                if (idal_is_needed (page_address(bv->bv_page), bv->bv_len))
                        cidaw += bv->bv_len >> (block->s2b_shift + 9);
#endif
        }
        /* Paranoia. */
        if (count != last_rec - first_rec + 1)
                return ERR_PTR(-EINVAL);

        /* use the prefix command if available */
        use_prefix = private->features.feature[8] & 0x01;
        if (use_prefix) {
                /* 1x prefix + number of blocks */
                cplength = 2 + count;
                /* 1x prefix + cidaws*sizeof(long) */
                datasize = sizeof(struct PFX_eckd_data) +
                        sizeof(struct LO_eckd_data) +
                        cidaw * sizeof(unsigned long);
        } else {
                /* 1x define extent + 1x locate record + number of blocks */
                cplength = 2 + count;
                /* 1x define extent + 1x locate record + cidaws*sizeof(long) */
                datasize = sizeof(struct DE_eckd_data) +
                        sizeof(struct LO_eckd_data) +
                        cidaw * sizeof(unsigned long);
        }
        /* Find out the number of additional locate record ccws for cdl. */
        if (private->uses_cdl && first_rec < 2*blk_per_trk) {
                if (last_rec >= 2*blk_per_trk)
                        count = 2*blk_per_trk - first_rec;
                cplength += count;
                datasize += count*sizeof(struct LO_eckd_data);
        }
        /* Allocate the ccw request. */
        cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, cplength, datasize,
                                   startdev);
        if (IS_ERR(cqr))
                return cqr;
        ccw = cqr->cpaddr;
        /* First ccw is define extent or prefix. */
        if (use_prefix) {
                if (prefix(ccw++, cqr->data, first_trk,
                           last_trk, cmd, basedev, startdev) == -EAGAIN) {
                        /* Clock not in sync and XRC is enabled.
                         * Try again later.
                         */
                        dasd_sfree_request(cqr, startdev);
                        return ERR_PTR(-EAGAIN);
                }
                idaws = (unsigned long *) (cqr->data +
                                           sizeof(struct PFX_eckd_data));
        } else {
                if (define_extent(ccw++, cqr->data, first_trk,
                                  last_trk, cmd, basedev) == -EAGAIN) {
                        /* Clock not in sync and XRC is enabled.
                         * Try again later.
                         */
                        dasd_sfree_request(cqr, startdev);
                        return ERR_PTR(-EAGAIN);
                }
                idaws = (unsigned long *) (cqr->data +
                                           sizeof(struct DE_eckd_data));
        }
        /* Build locate_record+read/write/ccws. */
        LO_data = (struct LO_eckd_data *) (idaws + cidaw);
        recid = first_rec;
        if (private->uses_cdl == 0 || recid > 2*blk_per_trk) {
                /* Only standard blocks so there is just one locate record. */
                ccw[-1].flags |= CCW_FLAG_CC;
                locate_record(ccw++, LO_data++, first_trk, first_offs + 1,
                              last_rec - recid + 1, cmd, basedev, blksize);
        }
        rq_for_each_segment(bv, req, iter) {
                dst = page_address(bv->bv_page) + bv->bv_offset;
                if (dasd_page_cache) {
                        char *copy = kmem_cache_alloc(dasd_page_cache,
                                                      GFP_DMA | __GFP_NOWARN);
                        if (copy && rq_data_dir(req) == WRITE)
                                memcpy(copy + bv->bv_offset, dst, bv->bv_len);
                        if (copy)
                                dst = copy + bv->bv_offset;
                }
                for (off = 0; off < bv->bv_len; off += blksize) {
                        sector_t trkid = recid;
                        unsigned int recoffs = sector_div(trkid, blk_per_trk);
                        rcmd = cmd;
                        count = blksize;
                        /* Locate record for cdl special block ? */
                        if (private->uses_cdl && recid < 2*blk_per_trk) {
                                if (dasd_eckd_cdl_special(blk_per_trk, recid)){
                                        rcmd |= 0x8;
                                        count = dasd_eckd_cdl_reclen(recid);
                                        if (count < blksize &&
                                            rq_data_dir(req) == READ)
                                                memset(dst + count, 0xe5,
                                                       blksize - count);
                                }
                                ccw[-1].flags |= CCW_FLAG_CC;
                                locate_record(ccw++, LO_data++,
                                              trkid, recoffs + 1,
                                              1, rcmd, basedev, count);
                        }
                        /* Locate record for standard blocks ? */
                        if (private->uses_cdl && recid == 2*blk_per_trk) {
                                ccw[-1].flags |= CCW_FLAG_CC;
                                locate_record(ccw++, LO_data++,
                                              trkid, recoffs + 1,
                                              last_rec - recid + 1,
                                              cmd, basedev, count);
                        }
                        /* Read/write ccw. */
                        ccw[-1].flags |= CCW_FLAG_CC;
                        ccw->cmd_code = rcmd;
                        ccw->count = count;
                        if (idal_is_needed(dst, blksize)) {
                                ccw->cda = (__u32)(addr_t) idaws;
                                ccw->flags = CCW_FLAG_IDA;
                                idaws = idal_create_words(idaws, dst, blksize);
                        } else {
                                ccw->cda = (__u32)(addr_t) dst;
                                ccw->flags = 0;
                        }
                        ccw++;
                        dst += blksize;
                        recid++;
                }
        }
        if (blk_noretry_request(req) ||
            block->base->features & DASD_FEATURE_FAILFAST)
                set_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags);
        cqr->startdev = startdev;
        cqr->memdev = startdev;
        cqr->block = block;
        cqr->expires = startdev->default_expires * HZ;  /* default 5 minutes */
        cqr->lpm = startdev->path_data.ppm;
        cqr->retries = 256;
        cqr->buildclk = get_clock();
        cqr->status = DASD_CQR_FILLED;
        return cqr;
}

static struct dasd_ccw_req *dasd_eckd_build_cp_cmd_track(
                                               struct dasd_device *startdev,
                                               struct dasd_block *block,
                                               struct request *req,
                                               sector_t first_rec,
                                               sector_t last_rec,
                                               sector_t first_trk,
                                               sector_t last_trk,
                                               unsigned int first_offs,
                                               unsigned int last_offs,
                                               unsigned int blk_per_trk,
                                               unsigned int blksize)
{
        unsigned long *idaws;
        struct dasd_ccw_req *cqr;
        struct ccw1 *ccw;
        struct req_iterator iter;
        struct bio_vec *bv;
        char *dst, *idaw_dst;
        unsigned int cidaw, cplength, datasize;
        unsigned int tlf;
        sector_t recid;
        unsigned char cmd;
        struct dasd_device *basedev;
        unsigned int trkcount, count, count_to_trk_end;
        unsigned int idaw_len, seg_len, part_len, len_to_track_end;
        unsigned char new_track, end_idaw;
        sector_t trkid;
        unsigned int recoffs;

        basedev = block->base;
        if (rq_data_dir(req) == READ)
                cmd = DASD_ECKD_CCW_READ_TRACK_DATA;
        else if (rq_data_dir(req) == WRITE)
                cmd = DASD_ECKD_CCW_WRITE_TRACK_DATA;
        else
                return ERR_PTR(-EINVAL);

        /* Track based I/O needs IDAWs for each page, and not just for
         * 64 bit addresses. We need additional idals for pages
         * that get filled from two tracks, so we use the number
         * of records as upper limit.
         */
        cidaw = last_rec - first_rec + 1;
        trkcount = last_trk - first_trk + 1;

        /* 1x prefix + one read/write ccw per track */
        cplength = 1 + trkcount;

        /* on 31-bit we need space for two 32 bit addresses per page
         * on 64-bit one 64 bit address
         */
        datasize = sizeof(struct PFX_eckd_data) +
                cidaw * sizeof(unsigned long long);

        /* Allocate the ccw request. */
        cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, cplength, datasize,
                                   startdev);
        if (IS_ERR(cqr))
                return cqr;
        ccw = cqr->cpaddr;
        /* transfer length factor: how many bytes to read from the last track */
        if (first_trk == last_trk)
                tlf = last_offs - first_offs + 1;
        else
                tlf = last_offs + 1;
        tlf *= blksize;

        if (prefix_LRE(ccw++, cqr->data, first_trk,
                       last_trk, cmd, basedev, startdev,
                       1 /* format */, first_offs + 1,
                       trkcount, blksize,
                       tlf) == -EAGAIN) {
                /* Clock not in sync and XRC is enabled.
                 * Try again later.
                 */
                dasd_sfree_request(cqr, startdev);
                return ERR_PTR(-EAGAIN);
        }

        /*
         * The translation of request into ccw programs must meet the
         * following conditions:
         * - all idaws but the first and the last must address full pages
         *   (or 2K blocks on 31-bit)
         * - the scope of a ccw and it's idal ends with the track boundaries
         */
        idaws = (unsigned long *) (cqr->data + sizeof(struct PFX_eckd_data));
        recid = first_rec;
        new_track = 1;
        end_idaw = 0;
        len_to_track_end = 0;
        idaw_dst = NULL;
        idaw_len = 0;
        rq_for_each_segment(bv, req, iter) {
                dst = page_address(bv->bv_page) + bv->bv_offset;
                seg_len = bv->bv_len;
                while (seg_len) {
                        if (new_track) {
                                trkid = recid;
                                recoffs = sector_div(trkid, blk_per_trk);
                                count_to_trk_end = blk_per_trk - recoffs;
                                count = min((last_rec - recid + 1),
                                            (sector_t)count_to_trk_end);
                                len_to_track_end = count * blksize;
                                ccw[-1].flags |= CCW_FLAG_CC;
                                ccw->cmd_code = cmd;
                                ccw->count = len_to_track_end;
                                ccw->cda = (__u32)(addr_t)idaws;
                                ccw->flags = CCW_FLAG_IDA;
                                ccw++;
                                recid += count;
                                new_track = 0;
                                /* first idaw for a ccw may start anywhere */
                                if (!idaw_dst)
                                        idaw_dst = dst;
                        }
                        /* If we start a new idaw, we must make sure that it
                         * starts on an IDA_BLOCK_SIZE boundary.
                         * If we continue an idaw, we must make sure that the
                         * current segment begins where the so far accumulated
                         * idaw ends
                         */
                        if (!idaw_dst) {
                                if (__pa(dst) & (IDA_BLOCK_SIZE-1)) {
                                        dasd_sfree_request(cqr, startdev);
                                        return ERR_PTR(-ERANGE);
                                } else
                                        idaw_dst = dst;
                        }
                        if ((idaw_dst + idaw_len) != dst) {
                                dasd_sfree_request(cqr, startdev);
                                return ERR_PTR(-ERANGE);
                        }
                        part_len = min(seg_len, len_to_track_end);
                        seg_len -= part_len;
                        dst += part_len;
                        idaw_len += part_len;
                        len_to_track_end -= part_len;
                        /* collected memory area ends on an IDA_BLOCK border,
                         * -> create an idaw
                         * idal_create_words will handle cases where idaw_len
                         * is larger then IDA_BLOCK_SIZE
                         */
                        if (!(__pa(idaw_dst + idaw_len) & (IDA_BLOCK_SIZE-1)))
                                end_idaw = 1;
                        /* We also need to end the idaw at track end */
                        if (!len_to_track_end) {
                                new_track = 1;
                                end_idaw = 1;
                        }
                        if (end_idaw) {
                                idaws = idal_create_words(idaws, idaw_dst,
                                                          idaw_len);
                                idaw_dst = NULL;
                                idaw_len = 0;
                                end_idaw = 0;
                        }
                }
        }

        if (blk_noretry_request(req) ||
            block->base->features & DASD_FEATURE_FAILFAST)
                set_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags);
        cqr->startdev = startdev;
        cqr->memdev = startdev;
        cqr->block = block;
        cqr->expires = startdev->default_expires * HZ;  /* default 5 minutes */
        cqr->lpm = startdev->path_data.ppm;
        cqr->retries = 256;
        cqr->buildclk = get_clock();
        cqr->status = DASD_CQR_FILLED;
        return cqr;
}

static int prepare_itcw(struct itcw *itcw,
                        unsigned int trk, unsigned int totrk, int cmd,
                        struct dasd_device *basedev,
                        struct dasd_device *startdev,
                        unsigned int rec_on_trk, int count,
                        unsigned int blksize,
                        unsigned int total_data_size,
                        unsigned int tlf,
                        unsigned int blk_per_trk)
{
        struct PFX_eckd_data pfxdata;
        struct dasd_eckd_private *basepriv, *startpriv;
        struct DE_eckd_data *dedata;
        struct LRE_eckd_data *lredata;
        struct dcw *dcw;

        u32 begcyl, endcyl;
        u16 heads, beghead, endhead;
        u8 pfx_cmd;

        int rc = 0;
        int sector = 0;
        int dn, d;


        /* setup prefix data */
        basepriv = (struct dasd_eckd_private *) basedev->private;
        startpriv = (struct dasd_eckd_private *) startdev->private;
        dedata = &pfxdata.define_extent;
        lredata = &pfxdata.locate_record;

        memset(&pfxdata, 0, sizeof(pfxdata));
        pfxdata.format = 1; /* PFX with LRE */
        pfxdata.base_address = basepriv->ned->unit_addr;
        pfxdata.base_lss = basepriv->ned->ID;
        pfxdata.validity.define_extent = 1;

        /* private uid is kept up to date, conf_data may be outdated */
        if (startpriv->uid.type != UA_BASE_DEVICE) {
                pfxdata.validity.verify_base = 1;
                if (startpriv->uid.type == UA_HYPER_PAV_ALIAS)
                        pfxdata.validity.hyper_pav = 1;
        }

        switch (cmd) {
        case DASD_ECKD_CCW_READ_TRACK_DATA:
                dedata->mask.perm = 0x1;
                dedata->attributes.operation = basepriv->attrib.operation;
                dedata->blk_size = blksize;
                dedata->ga_extended |= 0x42;
                lredata->operation.orientation = 0x0;
                lredata->operation.operation = 0x0C;
                lredata->auxiliary.check_bytes = 0x01;
                pfx_cmd = DASD_ECKD_CCW_PFX_READ;
                break;
        case DASD_ECKD_CCW_WRITE_TRACK_DATA:
                dedata->mask.perm = 0x02;
                dedata->attributes.operation = basepriv->attrib.operation;
                dedata->blk_size = blksize;
                rc = check_XRC_on_prefix(&pfxdata, basedev);
                dedata->ga_extended |= 0x42;
                lredata->operation.orientation = 0x0;
                lredata->operation.operation = 0x3F;
                lredata->extended_operation = 0x23;
                lredata->auxiliary.check_bytes = 0x2;
                pfx_cmd = DASD_ECKD_CCW_PFX;
                break;
        default:
                DBF_DEV_EVENT(DBF_ERR, basedev,
                              "prepare itcw, unknown opcode 0x%x", cmd);
                BUG();
                break;
        }
        if (rc)
                return rc;

        dedata->attributes.mode = 0x3;  /* ECKD */

        heads = basepriv->rdc_data.trk_per_cyl;
        begcyl = trk / heads;
        beghead = trk % heads;
        endcyl = totrk / heads;
        endhead = totrk % heads;

        /* check for sequential prestage - enhance cylinder range */
        if (dedata->attributes.operation == DASD_SEQ_PRESTAGE ||
            dedata->attributes.operation == DASD_SEQ_ACCESS) {

                if (endcyl + basepriv->attrib.nr_cyl < basepriv->real_cyl)
                        endcyl += basepriv->attrib.nr_cyl;
                else
                        endcyl = (basepriv->real_cyl - 1);
        }

        set_ch_t(&dedata->beg_ext, begcyl, beghead);
        set_ch_t(&dedata->end_ext, endcyl, endhead);

        dedata->ep_format = 0x20; /* records per track is valid */
        dedata->ep_rec_per_track = blk_per_trk;

        if (rec_on_trk) {
                switch (basepriv->rdc_data.dev_type) {
                case 0x3390:
                        dn = ceil_quot(blksize + 6, 232);
                        d = 9 + ceil_quot(blksize + 6 * (dn + 1), 34);
                        sector = (49 + (rec_on_trk - 1) * (10 + d)) / 8;
                        break;
                case 0x3380:
                        d = 7 + ceil_quot(blksize + 12, 32);
                        sector = (39 + (rec_on_trk - 1) * (8 + d)) / 7;
                        break;
                }
        }

        lredata->auxiliary.length_valid = 1;
        lredata->auxiliary.length_scope = 1;
        lredata->auxiliary.imbedded_ccw_valid = 1;
        lredata->length = tlf;
        lredata->imbedded_ccw = cmd;
        lredata->count = count;
        lredata->sector = sector;
        set_ch_t(&lredata->seek_addr, begcyl, beghead);
        lredata->search_arg.cyl = lredata->seek_addr.cyl;
        lredata->search_arg.head = lredata->seek_addr.head;
        lredata->search_arg.record = rec_on_trk;

        dcw = itcw_add_dcw(itcw, pfx_cmd, 0,
                     &pfxdata, sizeof(pfxdata), total_data_size);
        return IS_ERR(dcw) ? PTR_ERR(dcw) : 0;
}

static struct dasd_ccw_req *dasd_eckd_build_cp_tpm_track(
                                               struct dasd_device *startdev,
                                               struct dasd_block *block,
                                               struct request *req,
                                               sector_t first_rec,
                                               sector_t last_rec,
                                               sector_t first_trk,
                                               sector_t last_trk,
                                               unsigned int first_offs,
                                               unsigned int last_offs,
                                               unsigned int blk_per_trk,
                                               unsigned int blksize)
{
        struct dasd_ccw_req *cqr;
        struct req_iterator iter;
        struct bio_vec *bv;
        char *dst;
        unsigned int trkcount, ctidaw;
        unsigned char cmd;
        struct dasd_device *basedev;
        unsigned int tlf;
        struct itcw *itcw;
        struct tidaw *last_tidaw = NULL;
        int itcw_op;
        size_t itcw_size;
        u8 tidaw_flags;
        unsigned int seg_len, part_len, len_to_track_end;
        unsigned char new_track;
        sector_t recid, trkid;
        unsigned int offs;
        unsigned int count, count_to_trk_end;
        int ret;

        basedev = block->base;
        if (rq_data_dir(req) == READ) {
                cmd = DASD_ECKD_CCW_READ_TRACK_DATA;
                itcw_op = ITCW_OP_READ;
        } else if (rq_data_dir(req) == WRITE) {
                cmd = DASD_ECKD_CCW_WRITE_TRACK_DATA;
                itcw_op = ITCW_OP_WRITE;
        } else
                return ERR_PTR(-EINVAL);

        /* trackbased I/O needs address all memory via TIDAWs,
         * not just for 64 bit addresses. This allows us to map
         * each segment directly to one tidaw.
         * In the case of write requests, additional tidaws may
         * be needed when a segment crosses a track boundary.
         */
        trkcount = last_trk - first_trk + 1;
        ctidaw = 0;
        rq_for_each_segment(bv, req, iter) {
                ++ctidaw;
        }
        if (rq_data_dir(req) == WRITE)
                ctidaw += (last_trk - first_trk);

        /* Allocate the ccw request. */
        itcw_size = itcw_calc_size(0, ctidaw, 0);
        cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 0, itcw_size, startdev);
        if (IS_ERR(cqr))
                return cqr;

        /* transfer length factor: how many bytes to read from the last track */
        if (first_trk == last_trk)
                tlf = last_offs - first_offs + 1;
        else
                tlf = last_offs + 1;
        tlf *= blksize;

        itcw = itcw_init(cqr->data, itcw_size, itcw_op, 0, ctidaw, 0);
        if (IS_ERR(itcw)) {
                ret = -EINVAL;
                goto out_error;
        }
        cqr->cpaddr = itcw_get_tcw(itcw);
        if (prepare_itcw(itcw, first_trk, last_trk,
                         cmd, basedev, startdev,
                         first_offs + 1,
                         trkcount, blksize,
                         (last_rec - first_rec + 1) * blksize,
                         tlf, blk_per_trk) == -EAGAIN) {
                /* Clock not in sync and XRC is enabled.
                 * Try again later.
                 */
                ret = -EAGAIN;
                goto out_error;
        }
        len_to_track_end = 0;
        /*
         * A tidaw can address 4k of memory, but must not cross page boundaries
         * We can let the block layer handle this by setting
         * blk_queue_segment_boundary to page boundaries and
         * blk_max_segment_size to page size when setting up the request queue.
         * For write requests, a TIDAW must not cross track boundaries, because
         * we have to set the CBC flag on the last tidaw for each track.
         */
        if (rq_data_dir(req) == WRITE) {
                new_track = 1;
                recid = first_rec;
                rq_for_each_segment(bv, req, iter) {
                        dst = page_address(bv->bv_page) + bv->bv_offset;
                        seg_len = bv->bv_len;
                        while (seg_len) {
                                if (new_track) {
                                        trkid = recid;
                                        offs = sector_div(trkid, blk_per_trk);
                                        count_to_trk_end = blk_per_trk - offs;
                                        count = min((last_rec - recid + 1),
                                                    (sector_t)count_to_trk_end);
                                        len_to_track_end = count * blksize;
                                        recid += count;
                                        new_track = 0;
                                }
                                part_len = min(seg_len, len_to_track_end);
                                seg_len -= part_len;
                                len_to_track_end -= part_len;
                                /* We need to end the tidaw at track end */
                                if (!len_to_track_end) {
                                        new_track = 1;
                                        tidaw_flags = TIDAW_FLAGS_INSERT_CBC;
                                } else
                                        tidaw_flags = 0;
                                last_tidaw = itcw_add_tidaw(itcw, tidaw_flags,
                                                            dst, part_len);
                                if (IS_ERR(last_tidaw)) {
                                        ret = -EINVAL;
                                        goto out_error;
                                }
                                dst += part_len;
                        }
                }
        } else {
                rq_for_each_segment(bv, req, iter) {
                        dst = page_address(bv->bv_page) + bv->bv_offset;
                        last_tidaw = itcw_add_tidaw(itcw, 0x00,
                                                    dst, bv->bv_len);
                        if (IS_ERR(last_tidaw)) {
                                ret = -EINVAL;
                                goto out_error;
                        }
                }
        }
        last_tidaw->flags |= TIDAW_FLAGS_LAST;
        last_tidaw->flags &= ~TIDAW_FLAGS_INSERT_CBC;
        itcw_finalize(itcw);

        if (blk_noretry_request(req) ||
            block->base->features & DASD_FEATURE_FAILFAST)
                set_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags);
        cqr->cpmode = 1;
        cqr->startdev = startdev;
        cqr->memdev = startdev;
        cqr->block = block;
        cqr->expires = startdev->default_expires * HZ;  /* default 5 minutes */
        cqr->lpm = startdev->path_data.ppm;
        cqr->retries = 256;
        cqr->buildclk = get_clock();
        cqr->status = DASD_CQR_FILLED;
        return cqr;
out_error:
        dasd_sfree_request(cqr, startdev);
        return ERR_PTR(ret);
}

static struct dasd_ccw_req *dasd_eckd_build_cp(struct dasd_device *startdev,
                                               struct dasd_block *block,
                                               struct request *req)
{
        int cmdrtd, cmdwtd;
        int use_prefix;
        int fcx_multitrack;
        struct dasd_eckd_private *private;
        struct dasd_device *basedev;
        sector_t first_rec, last_rec;
        sector_t first_trk, last_trk;
        unsigned int first_offs, last_offs;
        unsigned int blk_per_trk, blksize;
        int cdlspecial;
        unsigned int data_size;
        struct dasd_ccw_req *cqr;

        basedev = block->base;
        private = (struct dasd_eckd_private *) basedev->private;