/*
 * Author(s)......: Holger Smolinski <Holger.Smolinski@de.ibm.com>
 * Bugreports.to..: <Linux390@de.ibm.com>
 * Copyright IBM Corp. 1999, 2009
 */

#define KMSG_COMPONENT "dasd-fba"

#include <linux/stddef.h>
#include <linux/kernel.h>
#include <asm/debug.h>

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

#include <asm/idals.h>
#include <asm/ebcdic.h>
#include <asm/io.h>
#include <asm/ccwdev.h>

#include "dasd_int.h"
#include "dasd_fba.h"

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

#define DASD_FBA_CCW_WRITE 0x41
#define DASD_FBA_CCW_READ 0x42
#define DASD_FBA_CCW_LOCATE 0x43
#define DASD_FBA_CCW_DEFINE_EXTENT 0x63

MODULE_LICENSE("GPL");

static struct dasd_discipline dasd_fba_discipline;

struct dasd_fba_private {
        struct dasd_fba_characteristics rdc_data;
};

static struct ccw_device_id dasd_fba_ids[] = {
        { CCW_DEVICE_DEVTYPE (0x6310, 0, 0x9336, 0), .driver_info = 0x1},
        { CCW_DEVICE_DEVTYPE (0x3880, 0, 0x3370, 0), .driver_info = 0x2},
        { /* end of list */ },
};

MODULE_DEVICE_TABLE(ccw, dasd_fba_ids);

static struct ccw_driver dasd_fba_driver; /* see below */
static int
dasd_fba_probe(struct ccw_device *cdev)
{
        return dasd_generic_probe(cdev, &dasd_fba_discipline);
}

static int
dasd_fba_set_online(struct ccw_device *cdev)
{
        return dasd_generic_set_online(cdev, &dasd_fba_discipline);
}

static struct ccw_driver dasd_fba_driver = {
        .driver = {
                .name   = "dasd-fba",
                .owner  = THIS_MODULE,
        },
        .ids         = dasd_fba_ids,
        .probe       = dasd_fba_probe,
        .remove      = dasd_generic_remove,
        .set_offline = dasd_generic_set_offline,
        .set_online  = dasd_fba_set_online,
        .notify      = dasd_generic_notify,
        .path_event  = dasd_generic_path_event,
        .freeze      = dasd_generic_pm_freeze,
        .thaw        = dasd_generic_restore_device,
        .restore     = dasd_generic_restore_device,
        .int_class   = IRQIO_DAS,
};

static void
define_extent(struct ccw1 * ccw, struct DE_fba_data *data, int rw,
              int blksize, int beg, int nr)
{
        ccw->cmd_code = DASD_FBA_CCW_DEFINE_EXTENT;
        ccw->flags = 0;
        ccw->count = 16;
        ccw->cda = (__u32) __pa(data);
        memset(data, 0, sizeof (struct DE_fba_data));
        if (rw == WRITE)
                (data->mask).perm = 0x0;
        else if (rw == READ)
                (data->mask).perm = 0x1;
        else
                data->mask.perm = 0x2;
        data->blk_size = blksize;
        data->ext_loc = beg;
        data->ext_end = nr - 1;
}

static void
locate_record(struct ccw1 * ccw, struct LO_fba_data *data, int rw,
              int block_nr, int block_ct)
{
        ccw->cmd_code = DASD_FBA_CCW_LOCATE;
        ccw->flags = 0;
        ccw->count = 8;
        ccw->cda = (__u32) __pa(data);
        memset(data, 0, sizeof (struct LO_fba_data));
        if (rw == WRITE)
                data->operation.cmd = 0x5;
        else if (rw == READ)
                data->operation.cmd = 0x6;
        else
                data->operation.cmd = 0x8;
        data->blk_nr = block_nr;
        data->blk_ct = block_ct;
}

static int
dasd_fba_check_characteristics(struct dasd_device *device)
{
        struct dasd_fba_private *private = device->private;
        struct ccw_device *cdev = device->cdev;
        struct dasd_block *block;
        int readonly, rc;

        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 = private;
        } else {
                memset(private, 0, sizeof(*private));
        }
        block = dasd_alloc_block();
        if (IS_ERR(block)) {
                DBF_EVENT_DEVID(DBF_WARNING, cdev, "%s", "could not allocate "
                                "dasd block structure");
                device->private = NULL;
                kfree(private);
                return PTR_ERR(block);
        }
        device->block = block;
        block->base = device;

        /* Read Device Characteristics */
        rc = dasd_generic_read_dev_chars(device, DASD_FBA_MAGIC,
                                         &private->rdc_data, 32);
        if (rc) {
                DBF_EVENT_DEVID(DBF_WARNING, cdev, "Read device "
                                "characteristics returned error %d", rc);
                device->block = NULL;
                dasd_free_block(block);
                device->private = NULL;
                kfree(private);
                return rc;
        }

        device->default_expires = DASD_EXPIRES;
        dasd_path_set_opm(device, LPM_ANYPATH);

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

        /* FBA supports discard, set the according feature bit */
        dasd_set_feature(cdev, DASD_FEATURE_DISCARD, 1);

        dev_info(&device->cdev->dev,
                 "New FBA DASD %04X/%02X (CU %04X/%02X) with %d MB "
                 "and %d B/blk%s\n",
                 cdev->id.dev_type,
                 cdev->id.dev_model,
                 cdev->id.cu_type,
                 cdev->id.cu_model,
                 ((private->rdc_data.blk_bdsa *
                   (private->rdc_data.blk_size >> 9)) >> 11),
                 private->rdc_data.blk_size,
                 readonly ? ", read-only device" : "");
        return 0;
}

static int dasd_fba_do_analysis(struct dasd_block *block)
{
        struct dasd_fba_private *private = block->base->private;
        int sb, rc;

        rc = dasd_check_blocksize(private->rdc_data.blk_size);
        if (rc) {
                DBF_DEV_EVENT(DBF_WARNING, block->base, "unknown blocksize %d",
                            private->rdc_data.blk_size);
                return rc;
        }
        block->blocks = private->rdc_data.blk_bdsa;
        block->bp_block = private->rdc_data.blk_size;
        block->s2b_shift = 0;   /* bits to shift 512 to get a block */
        for (sb = 512; sb < private->rdc_data.blk_size; sb = sb << 1)
                block->s2b_shift++;
        return 0;
}

static int dasd_fba_fill_geometry(struct dasd_block *block,
                                  struct hd_geometry *geo)
{
        if (dasd_check_blocksize(block->bp_block) != 0)
                return -EINVAL;
        geo->cylinders = (block->blocks << block->s2b_shift) >> 10;
        geo->heads = 16;
        geo->sectors = 128 >> block->s2b_shift;
        return 0;
}

static dasd_erp_fn_t
dasd_fba_erp_action(struct dasd_ccw_req * cqr)
{
        return dasd_default_erp_action;
}

static dasd_erp_fn_t
dasd_fba_erp_postaction(struct dasd_ccw_req * cqr)
{
        if (cqr->function == dasd_default_erp_action)
                return dasd_default_erp_postaction;

        DBF_DEV_EVENT(DBF_WARNING, cqr->startdev, "unknown ERP action %p",
                    cqr->function);
        return NULL;
}

static void dasd_fba_check_for_device_change(struct dasd_device *device,
                                             struct dasd_ccw_req *cqr,
                                             struct irb *irb)
{
        char mask;

        /* first of all check for state change pending interrupt */
        mask = DEV_STAT_ATTENTION | DEV_STAT_DEV_END | DEV_STAT_UNIT_EXCEP;
        if ((irb->scsw.cmd.dstat & mask) == mask)
                dasd_generic_handle_state_change(device);
};


/*
 * Builds a CCW with no data payload
 */
static void ccw_write_no_data(struct ccw1 *ccw)
{
        ccw->cmd_code = DASD_FBA_CCW_WRITE;
        ccw->flags |= CCW_FLAG_SLI;
        ccw->count = 0;
}

/*
 * Builds a CCW that writes only zeroes.
 */
static void ccw_write_zero(struct ccw1 *ccw, int count)
{
        ccw->cmd_code = DASD_FBA_CCW_WRITE;
        ccw->flags |= CCW_FLAG_SLI;
        ccw->count = count;
        ccw->cda = (__u32) (addr_t) page_to_phys(ZERO_PAGE(0));
}

/*
 * Helper function to count the amount of necessary CCWs within a given range
 * with 4k alignment and command chaining in mind.
 */
static int count_ccws(sector_t first_rec, sector_t last_rec,
                      unsigned int blocks_per_page)
{
        sector_t wz_stop = 0, d_stop = 0;
        int cur_pos = 0;
        int count = 0;

        if (first_rec % blocks_per_page != 0) {
                wz_stop = first_rec + blocks_per_page -
                        (first_rec % blocks_per_page) - 1;
                if (wz_stop > last_rec)
                        wz_stop = last_rec;
                cur_pos = wz_stop - first_rec + 1;
                count++;
        }

        if (last_rec - (first_rec + cur_pos) + 1 >= blocks_per_page) {
                if ((last_rec - blocks_per_page + 1) % blocks_per_page != 0)
                        d_stop = last_rec - ((last_rec - blocks_per_page + 1) %
                                             blocks_per_page);
                else
                        d_stop = last_rec;

                cur_pos += d_stop - (first_rec + cur_pos) + 1;
                count++;
        }

        if (cur_pos == 0 || first_rec + cur_pos - 1 < last_rec)
                count++;

        return count;
}

/*
 * This function builds a CCW request for block layer discard requests.
 * Each page in the z/VM hypervisor that represents certain records of an FBA
 * device will be padded with zeros. This is a special behaviour of the WRITE
 * command which is triggered when no data payload is added to the CCW.
 *
 * Note: Due to issues in some z/VM versions, we can't fully utilise this
 * special behaviour. We have to keep a 4k (or 8 block) alignment in mind to
 * work around those issues and write actual zeroes to the unaligned parts in
 * the request. This workaround might be removed in the future.
 */
static struct dasd_ccw_req *dasd_fba_build_cp_discard(
                                                struct dasd_device *memdev,
                                                struct dasd_block *block,
                                                struct request *req)
{
        struct LO_fba_data *LO_data;
        struct dasd_ccw_req *cqr;
        struct ccw1 *ccw;

        sector_t wz_stop = 0, d_stop = 0;
        sector_t first_rec, last_rec;

        unsigned int blksize = block->bp_block;
        unsigned int blocks_per_page;
        int wz_count = 0;
        int d_count = 0;
        int cur_pos = 0; /* Current position within the extent */
        int count = 0;
        int cplength;
        int datasize;
        int nr_ccws;

        first_rec = blk_rq_pos(req) >> block->s2b_shift;
        last_rec =
                (blk_rq_pos(req) + blk_rq_sectors(req) - 1) >> block->s2b_shift;
        count = last_rec - first_rec + 1;

        blocks_per_page = BLOCKS_PER_PAGE(blksize);
        nr_ccws = count_ccws(first_rec, last_rec, blocks_per_page);

        /* define extent + nr_ccws * locate record + nr_ccws * single CCW */
        cplength = 1 + 2 * nr_ccws;
        datasize = sizeof(struct DE_fba_data) +
                nr_ccws * (sizeof(struct LO_fba_data) + sizeof(struct ccw1));

        cqr = dasd_smalloc_request(DASD_FBA_MAGIC, cplength, datasize, memdev);
        if (IS_ERR(cqr))
                return cqr;

        ccw = cqr->cpaddr;

        define_extent(ccw++, cqr->data, WRITE, blksize, first_rec, count);
        LO_data = cqr->data + sizeof(struct DE_fba_data);

        /* First part is not aligned. Calculate range to write zeroes. */
        if (first_rec % blocks_per_page != 0) {
                wz_stop = first_rec + blocks_per_page -
                        (first_rec % blocks_per_page) - 1;
                if (wz_stop > last_rec)
                        wz_stop = last_rec;
                wz_count = wz_stop - first_rec + 1;

                ccw[-1].flags |= CCW_FLAG_CC;
                locate_record(ccw++, LO_data++, WRITE, cur_pos, wz_count);

                ccw[-1].flags |= CCW_FLAG_CC;
                ccw_write_zero(ccw++, wz_count * blksize);

                cur_pos = wz_count;
        }

        /* We can do proper discard when we've got at least blocks_per_page blocks. */
        if (last_rec - (first_rec + cur_pos) + 1 >= blocks_per_page) {
                /* is last record at page boundary? */
                if ((last_rec - blocks_per_page + 1) % blocks_per_page != 0)
                        d_stop = last_rec - ((last_rec - blocks_per_page + 1) %
                                             blocks_per_page);
                else
                        d_stop = last_rec;

                d_count = d_stop - (first_rec + cur_pos) + 1;

                ccw[-1].flags |= CCW_FLAG_CC;
                locate_record(ccw++, LO_data++, WRITE, cur_pos, d_count);

                ccw[-1].flags |= CCW_FLAG_CC;
                ccw_write_no_data(ccw++);

                cur_pos += d_count;
        }

        /* We might still have some bits left which need to be zeroed. */
        if (cur_pos == 0 || first_rec + cur_pos - 1 < last_rec) {
                if (d_stop != 0)
                        wz_count = last_rec - d_stop;
                else if (wz_stop != 0)
                        wz_count = last_rec - wz_stop;
                else
                        wz_count = count;

                ccw[-1].flags |= CCW_FLAG_CC;
                locate_record(ccw++, LO_data++, WRITE, cur_pos, wz_count);

                ccw[-1].flags |= CCW_FLAG_CC;
                ccw_write_zero(ccw++, wz_count * blksize);
        }

        if (blk_noretry_request(req) ||
            block->base->features & DASD_FEATURE_FAILFAST)
                set_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags);

        cqr->startdev = memdev;
        cqr->memdev = memdev;
        cqr->block = block;
        cqr->expires = memdev->default_expires * HZ;    /* default 5 minutes */
        cqr->retries = 32;
        cqr->buildclk = get_tod_clock();
        cqr->status = DASD_CQR_FILLED;

        return cqr;
}

static struct dasd_ccw_req *dasd_fba_build_cp_regular(
                                                struct dasd_device *memdev,
                                                struct dasd_block *block,
                                                struct request *req)
{
        struct dasd_fba_private *private = block->base->private;
        unsigned long *idaws;
        struct LO_fba_data *LO_data;
        struct dasd_ccw_req *cqr;
        struct ccw1 *ccw;
        struct req_iterator iter;
        struct bio_vec *bv;
        char *dst;
        int count, cidaw, cplength, datasize;
        sector_t recid, first_rec, last_rec;
        unsigned int blksize, off;
        unsigned char cmd;

        if (rq_data_dir(req) == READ) {
                cmd = DASD_FBA_CCW_READ;
        } else if (rq_data_dir(req) == WRITE) {
                cmd = DASD_FBA_CCW_WRITE;
        } else
                return ERR_PTR(-EINVAL);
        blksize = block->bp_block;
        /* Calculate record id of first and last block. */
        first_rec = blk_rq_pos(req) >> block->s2b_shift;
        last_rec =
                (blk_rq_pos(req) + blk_rq_sectors(req) - 1) >> block->s2b_shift;
        /* 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))
                        /* Fba 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 / blksize;
#endif
        }
        /* Paranoia. */
        if (count != last_rec - first_rec + 1)
                return ERR_PTR(-EINVAL);
        /* 1x define extent + 1x locate record + number of blocks */
        cplength = 2 + count;
        /* 1x define extent + 1x locate record */
        datasize = sizeof(struct DE_fba_data) + sizeof(struct LO_fba_data) +
                cidaw * sizeof(unsigned long);
        /*
         * Find out number of additional locate record ccws if the device
         * can't do data chaining.
         */
        if (private->rdc_data.mode.bits.data_chain == 0) {
                cplength += count - 1;
                datasize += (count - 1)*sizeof(struct LO_fba_data);
        }
        /* Allocate the ccw request. */
        cqr = dasd_smalloc_request(DASD_FBA_MAGIC, cplength, datasize, memdev);
        if (IS_ERR(cqr))
                return cqr;
        ccw = cqr->cpaddr;
        /* First ccw is define extent. */
        define_extent(ccw++, cqr->data, rq_data_dir(req),
                      block->bp_block, blk_rq_pos(req), blk_rq_sectors(req));
        /* Build locate_record + read/write ccws. */
        idaws = (unsigned long *) (cqr->data + sizeof(struct DE_fba_data));
        LO_data = (struct LO_fba_data *) (idaws + cidaw);
        /* Locate record for all blocks for smart devices. */
        if (private->rdc_data.mode.bits.data_chain != 0) {
                ccw[-1].flags |= CCW_FLAG_CC;
                locate_record(ccw++, LO_data++, rq_data_dir(req), 0, count);
        }
        recid = first_rec;
        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) {
                        /* Locate record for stupid devices. */
                        if (private->rdc_data.mode.bits.data_chain == 0) {
                                ccw[-1].flags |= CCW_FLAG_CC;
                                locate_record(ccw, LO_data++,
                                              rq_data_dir(req),
                                              recid - first_rec, 1);
                                ccw->flags = CCW_FLAG_CC;
                                ccw++;
                        } else {
                                if (recid > first_rec)
                                        ccw[-1].flags |= CCW_FLAG_DC;
                                else
                                        ccw[-1].flags |= CCW_FLAG_CC;
                        }
                        ccw->cmd_code = cmd;
                        ccw->count = block->bp_block;
                        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 = memdev;
        cqr->memdev = memdev;
        cqr->block = block;
        cqr->expires = memdev->default_expires * HZ;    /* default 5 minutes */
        cqr->retries = 32;
        cqr->buildclk = get_tod_clock();
        cqr->status = DASD_CQR_FILLED;
        return cqr;
}

static struct dasd_ccw_req *dasd_fba_build_cp(struct dasd_device *memdev,
                                              struct dasd_block *block,
                                              struct request *req)
{
        if (req_op(req) == REQ_OP_DISCARD)
                return dasd_fba_build_cp_discard(memdev, block, req);
        else
                return dasd_fba_build_cp_regular(memdev, block, req);
}

static int
dasd_fba_free_cp(struct dasd_ccw_req *cqr, struct request *req)
{
        struct dasd_fba_private *private = cqr->block->base->private;
        struct ccw1 *ccw;
        struct req_iterator iter;
        struct bio_vec *bv;
        char *dst, *cda;
        unsigned int blksize, off;
        int status;

        if (!dasd_page_cache)
                goto out;
        blksize = cqr->block->bp_block;
        ccw = cqr->cpaddr;
        /* Skip over define extent & locate record. */
        ccw++;
        if (private->rdc_data.mode.bits.data_chain != 0)
                ccw++;
        rq_for_each_segment(bv, req, iter) {
                dst = page_address(bv->bv_page) + bv->bv_offset;
                for (off = 0; off < bv->bv_len; off += blksize) {
                        /* Skip locate record. */
                        if (private->rdc_data.mode.bits.data_chain == 0)
                                ccw++;
                        if (dst) {
                                if (ccw->flags & CCW_FLAG_IDA)
                                        cda = *((char **)((addr_t) ccw->cda));
                                else
                                        cda = (char *)((addr_t) ccw->cda);
                                if (dst != cda) {
                                        if (rq_data_dir(req) == READ)
                                                memcpy(dst, cda, bv->bv_len);
                                        kmem_cache_free(dasd_page_cache,
                                            (void *)((addr_t)cda & PAGE_MASK));
                                }
                                dst = NULL;
                        }
                        ccw++;
                }
        }
out:
        status = cqr->status == DASD_CQR_DONE;
        dasd_sfree_request(cqr, cqr->memdev);
        return status;
}

static void dasd_fba_handle_terminated_request(struct dasd_ccw_req *cqr)
{
        cqr->status = DASD_CQR_FILLED;
};

static int
dasd_fba_fill_info(struct dasd_device * device,
                   struct dasd_information2_t * info)
{
        struct dasd_fba_private *private = device->private;

        info->label_block = 1;
        info->FBA_layout = 1;
        info->format = DASD_FORMAT_LDL;
        info->characteristics_size = sizeof(private->rdc_data);
        memcpy(info->characteristics, &private->rdc_data,
               sizeof(private->rdc_data));
        info->confdata_size = 0;
        return 0;
}

static void
dasd_fba_dump_sense_dbf(struct dasd_device *device, struct irb *irb,
                        char *reason)
{
        u64 *sense;

        sense = (u64 *) dasd_get_sense(irb);
        if (sense) {
                DBF_DEV_EVENT(DBF_EMERG, device,
                              "%s: %s %02x%02x%02x %016llx %016llx %016llx "
                              "%016llx", reason,
                              scsw_is_tm(&irb->scsw) ? "t" : "c",
                              scsw_cc(&irb->scsw), scsw_cstat(&irb->scsw),
                              scsw_dstat(&irb->scsw), sense[0], sense[1],
                              sense[2], sense[3]);
        } else {
                DBF_DEV_EVENT(DBF_EMERG, device, "%s",
                              "SORRY - NO VALID SENSE AVAILABLE\n");
        }
}


static void
dasd_fba_dump_sense(struct dasd_device *device, struct dasd_ccw_req * req,
                    struct irb *irb)
{
        char *page;
        struct ccw1 *act, *end, *last;
        int len, sl, sct, count;

        page = (char *) get_zeroed_page(GFP_ATOMIC);
        if (page == NULL) {
                DBF_DEV_EVENT(DBF_WARNING, device, "%s",
                            "No memory to dump sense data");
                return;
        }
        len = sprintf(page, PRINTK_HEADER
                      " I/O status report for device %s:\n",
                      dev_name(&device->cdev->dev));
        len += sprintf(page + len, PRINTK_HEADER
                       " in req: %p CS: 0x%02X DS: 0x%02X\n", req,
                       irb->scsw.cmd.cstat, irb->scsw.cmd.dstat);
        len += sprintf(page + len, PRINTK_HEADER
                       " device %s: Failing CCW: %p\n",
                       dev_name(&device->cdev->dev),
                       (void *) (addr_t) irb->scsw.cmd.cpa);
        if (irb->esw.esw0.erw.cons) {
                for (sl = 0; sl < 4; sl++) {
                        len += sprintf(page + len, PRINTK_HEADER
                                       " Sense(hex) %2d-%2d:",
                                       (8 * sl), ((8 * sl) + 7));

                        for (sct = 0; sct < 8; sct++) {
                                len += sprintf(page + len, " %02x",
                                               irb->ecw[8 * sl + sct]);
                        }
                        len += sprintf(page + len, "\n");
                }
        } else {
                len += sprintf(page + len, PRINTK_HEADER
                               " SORRY - NO VALID SENSE AVAILABLE\n");
        }
        printk(KERN_ERR "%s", page);

        /* dump the Channel Program */
        /* print first CCWs (maximum 8) */
        act = req->cpaddr;
        for (last = act; last->flags & (CCW_FLAG_CC | CCW_FLAG_DC); last++);
        end = min(act + 8, last);
        len = sprintf(page, PRINTK_HEADER " Related CP in req: %p\n", req);
        while (act <= end) {
                len += sprintf(page + len, PRINTK_HEADER
                               " CCW %p: %08X %08X DAT:",
                               act, ((int *) act)[0], ((int *) act)[1]);
                for (count = 0; count < 32 && count < act->count;
                     count += sizeof(int))
                        len += sprintf(page + len, " %08X",
                                       ((int *) (addr_t) act->cda)
                                       [(count>>2)]);
                len += sprintf(page + len, "\n");
                act++;
        }
        printk(KERN_ERR "%s", page);


        /* print failing CCW area */
        len = 0;
        if (act <  ((struct ccw1 *)(addr_t) irb->scsw.cmd.cpa) - 2) {
                act = ((struct ccw1 *)(addr_t) irb->scsw.cmd.cpa) - 2;
                len += sprintf(page + len, PRINTK_HEADER "......\n");
        }
        end = min((struct ccw1 *)(addr_t) irb->scsw.cmd.cpa + 2, last);
        while (act <= end) {
                len += sprintf(page + len, PRINTK_HEADER
                               " CCW %p: %08X %08X DAT:",
                               act, ((int *) act)[0], ((int *) act)[1]);
                for (count = 0; count < 32 && count < act->count;
                     count += sizeof(int))
                        len += sprintf(page + len, " %08X",
                                       ((int *) (addr_t) act->cda)
                                       [(count>>2)]);
                len += sprintf(page + len, "\n");
                act++;
        }

        /* print last CCWs */
        if (act <  last - 2) {
                act = last - 2;
                len += sprintf(page + len, PRINTK_HEADER "......\n");
        }
        while (act <= last) {
                len += sprintf(page + len, PRINTK_HEADER
                               " CCW %p: %08X %08X DAT:",
                               act, ((int *) act)[0], ((int *) act)[1]);
                for (count = 0; count < 32 && count < act->count;
                     count += sizeof(int))
                        len += sprintf(page + len, " %08X",
                                       ((int *) (addr_t) act->cda)
                                       [(count>>2)]);
                len += sprintf(page + len, "\n");
                act++;
        }
        if (len > 0)
                printk(KERN_ERR "%s", page);
        free_page((unsigned long) page);
}

/*
 * max_blocks is dependent on the amount of storage that is available
 * in the static io buffer for each device. Currently each device has
 * 8192 bytes (=2 pages). For 64 bit one dasd_mchunkt_t structure has
 * 24 bytes, the struct dasd_ccw_req has 136 bytes and each block can use
 * up to 16 bytes (8 for the ccw and 8 for the idal pointer). In
 * addition we have one define extent ccw + 16 bytes of data and a
 * locate record ccw for each block (stupid devices!) + 16 bytes of data.
 * That makes:
 * (8192 - 24 - 136 - 8 - 16) / 40 = 200.2 blocks at maximum.
 * We want to fit two into the available memory so that we can immediately
 * start the next request if one finishes off. That makes 100.1 blocks
 * for one request. Give a little safety and the result is 96.
 */
static struct dasd_discipline dasd_fba_discipline = {
        .owner = THIS_MODULE,
        .name = "FBA ",
        .ebcname = "FBA ",
        .max_blocks = 96,
        .check_device = dasd_fba_check_characteristics,
        .do_analysis = dasd_fba_do_analysis,
        .verify_path = dasd_generic_verify_path,
        .fill_geometry = dasd_fba_fill_geometry,
        .start_IO = dasd_start_IO,
        .term_IO = dasd_term_IO,
        .handle_terminated_request = dasd_fba_handle_terminated_request,
        .erp_action = dasd_fba_erp_action,
        .erp_postaction = dasd_fba_erp_postaction,
        .check_for_device_change = dasd_fba_check_for_device_change,
        .build_cp = dasd_fba_build_cp,
        .free_cp = dasd_fba_free_cp,
        .dump_sense = dasd_fba_dump_sense,
        .dump_sense_dbf = dasd_fba_dump_sense_dbf,
        .fill_info = dasd_fba_fill_info,
};

static int __init
dasd_fba_init(void)
{
        int ret;

        ASCEBC(dasd_fba_discipline.ebcname, 4);
        ret = ccw_driver_register(&dasd_fba_driver);
        if (!ret)
                wait_for_device_probe();

        return ret;
}

static void __exit
dasd_fba_cleanup(void)
{
        ccw_driver_unregister(&dasd_fba_driver);
}

module_init(dasd_fba_init);
module_exit(dasd_fba_cleanup);