/*      $NetBSD: sd.c,v 1.6 2019/01/08 19:41:09 jdolecek Exp $  */
/*
 * Copyright (c) 2010 KIYOHARA Takashi
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/param.h>
#include <sys/types.h>
#include <sys/stdint.h>

#include <lib/libsa/stand.h>
#include <lib/libkern/libkern.h>

#include "boot.h"
#include "sdvar.h"

#ifdef DEBUG
#define DPRINTF(x)      printf x
#else
#define DPRINTF(x)
#endif

#define SD_DEFAULT_BLKSIZE      512


struct sd_mode_sense_data {
        struct scsi_mode_parameter_header_6 header;
        struct scsi_general_block_descriptor blk_desc;
        union scsi_disk_pages pages;
};

static int sd_validate_blksize(int);
static uint64_t sd_read_capacity(struct sd_softc *, int *);
static int sd_get_simplifiedparms(struct sd_softc *);
static int sd_get_capacity(struct sd_softc *);
static int sd_get_parms_page4(struct sd_softc *, struct disk_parms *);
static int sd_get_parms_page5(struct sd_softc *, struct disk_parms *);
static int sd_get_parms(struct sd_softc *);
static void sdgetdefaultlabel(struct sd_softc *, struct disklabel *);
static int sdgetdisklabel(struct sd_softc *);

int sdopen(struct open_file *, ...);
int sdclose(struct open_file *);
int sdstrategy(void *, int, daddr_t, size_t, void *, size_t *);


static int
sd_validate_blksize(int len)
{

        switch (len) {
        case 256:
        case 512:
        case 1024:
        case 2048:
        case 4096:
                return 1;
        }
        return 0;
}

/*
 * sd_read_capacity:
 *
 *      Find out from the device what its capacity is.
 */
static uint64_t
sd_read_capacity(struct sd_softc *sd, int *blksize)
{
        union {
                struct scsipi_read_capacity_10 cmd;
                struct scsipi_read_capacity_16 cmd16;
        } cmd;
        union {
                struct scsipi_read_capacity_10_data data;
                struct scsipi_read_capacity_16_data data16;
        } data;
        uint64_t rv;

        memset(&cmd, 0, sizeof(cmd));
        cmd.cmd.opcode = READ_CAPACITY_10;

        /*
         * If the command works, interpret the result as a 4 byte
         * number of blocks
         */
        rv = 0;
        memset(&data, 0, sizeof(data.data));
        if (scsi_command(sd, (void *)&cmd.cmd, sizeof(cmd.cmd),
            (void *)&data, sizeof(data.data)) != 0)
                goto out;

        if (_4btol(data.data.addr) != 0xffffffff) {
                *blksize = _4btol(data.data.length);
                rv = _4btol(data.data.addr) + 1;
                goto out;
        }

        /*
         * Device is larger than can be reflected by READ CAPACITY (10).
         * Try READ CAPACITY (16).
         */

        memset(&cmd, 0, sizeof(cmd));
        cmd.cmd16.opcode = READ_CAPACITY_16;
        cmd.cmd16.byte2 = SRC16_SERVICE_ACTION;
        _lto4b(sizeof(data.data16), cmd.cmd16.len);

        memset(&data, 0, sizeof(data.data16));
        if (scsi_command(sd, (void *)&cmd.cmd16, sizeof(cmd.cmd16),
            (void *)&data, sizeof(data.data16)) != 0)
                goto out;

        *blksize = _4btol(data.data16.length);
        rv = _8btol(data.data16.addr) + 1;

 out:
        return rv;
}

static int
sd_get_simplifiedparms(struct sd_softc *sd)
{
        struct {
                struct scsi_mode_parameter_header_6 header;
                /* no block descriptor */
                uint8_t pg_code; /* page code (should be 6) */
                uint8_t pg_length; /* page length (should be 11) */
                uint8_t wcd; /* bit0: cache disable */
                uint8_t lbs[2]; /* logical block size */
                uint8_t size[5]; /* number of log. blocks */
                uint8_t pp; /* power/performance */
                uint8_t flags;
                uint8_t resvd;
        } scsipi_sense;
        struct disk_parms *dp = &sd->sc_params;
        uint64_t blocks;
        int error, blksize;

        /*
         * sd_read_capacity (ie "read capacity") and mode sense page 6
         * give the same information. Do both for now, and check
         * for consistency.
         * XXX probably differs for removable media
         */
        dp->blksize = SD_DEFAULT_BLKSIZE;
        if ((blocks = sd_read_capacity(sd, &blksize)) == 0)
                return SDGP_RESULT_OFFLINE;             /* XXX? */

        error = scsi_mode_sense(sd, SMS_DBD, 6,
            &scsipi_sense.header, sizeof(scsipi_sense));

        if (error != 0)
                return SDGP_RESULT_OFFLINE;             /* XXX? */

        dp->blksize = blksize;
        if (!sd_validate_blksize(dp->blksize))
                dp->blksize = _2btol(scsipi_sense.lbs);
        if (!sd_validate_blksize(dp->blksize))
                dp->blksize = SD_DEFAULT_BLKSIZE;

        /*
         * Create a pseudo-geometry.
         */
        dp->heads = 64;
        dp->sectors = 32;
        dp->cyls = blocks / (dp->heads * dp->sectors);
        dp->disksize = _5btol(scsipi_sense.size);
        if (dp->disksize <= UINT32_MAX && dp->disksize != blocks) {
                printf("RBC size: mode sense=%llu, get cap=%llu\n",
                       (unsigned long long)dp->disksize,
                       (unsigned long long)blocks);
                dp->disksize = blocks;
        }
        dp->disksize512 = (dp->disksize * dp->blksize) / DEV_BSIZE;

        return SDGP_RESULT_OK;
}

/*
 * Get the scsi driver to send a full inquiry to the * device and use the
 * results to fill out the disk parameter structure.
 */
static int
sd_get_capacity(struct sd_softc *sd)
{
        struct disk_parms *dp = &sd->sc_params;
        uint64_t blocks;
        int error, blksize;

        dp->disksize = blocks = sd_read_capacity(sd, &blksize);
        if (blocks == 0) {
                struct scsipi_read_format_capacities cmd;
                struct {
                        struct scsipi_capacity_list_header header;
                        struct scsipi_capacity_descriptor desc;
                } __packed data;

                memset(&cmd, 0, sizeof(cmd));
                memset(&data, 0, sizeof(data));
                cmd.opcode = READ_FORMAT_CAPACITIES;
                _lto2b(sizeof(data), cmd.length);

                error = scsi_command(sd,
                    (void *)&cmd, sizeof(cmd), (void *)&data, sizeof(data));
                if (error == EFTYPE)
                        /* Medium Format Corrupted, handle as not formatted */
                        return SDGP_RESULT_UNFORMATTED;
                if (error || data.header.length == 0)
                        return SDGP_RESULT_OFFLINE;

                switch (data.desc.byte5 & SCSIPI_CAP_DESC_CODE_MASK) {
                case SCSIPI_CAP_DESC_CODE_RESERVED:
                case SCSIPI_CAP_DESC_CODE_FORMATTED:
                        break;

                case SCSIPI_CAP_DESC_CODE_UNFORMATTED:
                        return SDGP_RESULT_UNFORMATTED;

                case SCSIPI_CAP_DESC_CODE_NONE:
                        return SDGP_RESULT_OFFLINE;
                }

                dp->disksize = blocks = _4btol(data.desc.nblks);
                if (blocks == 0)
                        return SDGP_RESULT_OFFLINE;             /* XXX? */

                blksize = _3btol(data.desc.blklen);

        } else if (!sd_validate_blksize(blksize)) {
                struct sd_mode_sense_data scsipi_sense;
                int bsize;

                memset(&scsipi_sense, 0, sizeof(scsipi_sense));
                error = scsi_mode_sense(sd, 0, 0, &scsipi_sense.header,
                    sizeof(struct scsi_mode_parameter_header_6) +
                                                sizeof(scsipi_sense.blk_desc));
                if (!error) {
                        bsize = scsipi_sense.header.blk_desc_len;

                        if (bsize >= 8)
                                blksize = _3btol(scsipi_sense.blk_desc.blklen);
                }
        }

        if (!sd_validate_blksize(blksize))
                blksize = SD_DEFAULT_BLKSIZE;

        dp->blksize = blksize;
        dp->disksize512 = (blocks * dp->blksize) / DEV_BSIZE;
        return 0;
}

static int
sd_get_parms_page4(struct sd_softc *sd, struct disk_parms *dp)
{
        struct sd_mode_sense_data scsipi_sense;
        union scsi_disk_pages *pages;
        size_t poffset;
        int byte2, error;

        byte2 = SMS_DBD;
again:
        memset(&scsipi_sense, 0, sizeof(scsipi_sense));
        error = scsi_mode_sense(sd, byte2, 4, &scsipi_sense.header,
            (byte2 ? 0 : sizeof(scsipi_sense.blk_desc)) +
                                sizeof(scsipi_sense.pages.rigid_geometry));
        if (error) {
                if (byte2 == SMS_DBD) {
                        /* No result; try once more with DBD off */
                        byte2 = 0;
                        goto again;
                }
                return error;
        }

        poffset = sizeof(scsipi_sense.header);
        poffset += scsipi_sense.header.blk_desc_len;

        if (poffset > sizeof(scsipi_sense) - sizeof(pages->rigid_geometry))
                return ERESTART;

        pages = (void *)((u_long)&scsipi_sense + poffset);
#if 0
        {
                size_t i;
                u_int8_t *p;

                printf("page 4 sense:");
                for (i = sizeof(scsipi_sense), p = (void *)&scsipi_sense; i;
                    i--, p++)
                        printf(" %02x", *p);
                printf("\n");
                printf("page 4 pg_code=%d sense=%p/%p\n",
                    pages->rigid_geometry.pg_code, &scsipi_sense, pages);
        }
#endif

        if ((pages->rigid_geometry.pg_code & PGCODE_MASK) != 4)
                return ERESTART;

        /*
         * KLUDGE!! (for zone recorded disks)
         * give a number of sectors so that sec * trks * cyls
         * is <= disk_size
         * can lead to wasted space! THINK ABOUT THIS !
         */
        dp->heads = pages->rigid_geometry.nheads;
        dp->cyls = _3btol(pages->rigid_geometry.ncyl);
        if (dp->heads == 0 || dp->cyls == 0)
                return ERESTART;
        dp->sectors = dp->disksize / (dp->heads * dp->cyls);    /* XXX */

        dp->rot_rate = _2btol(pages->rigid_geometry.rpm);
        if (dp->rot_rate == 0)
                dp->rot_rate = 3600;

#if 0
printf("page 4 ok\n");
#endif
        return 0;
}

static int
sd_get_parms_page5(struct sd_softc *sd, struct disk_parms *dp)
{
        struct sd_mode_sense_data scsipi_sense;
        union scsi_disk_pages *pages;
        size_t poffset;
        int byte2, error;

        byte2 = SMS_DBD;
again:
        memset(&scsipi_sense, 0, sizeof(scsipi_sense));
        error = scsi_mode_sense(sd, 0, 5, &scsipi_sense.header,
            (byte2 ? 0 : sizeof(scsipi_sense.blk_desc)) +
                                sizeof(scsipi_sense.pages.flex_geometry));
        if (error) {
                if (byte2 == SMS_DBD) {
                        /* No result; try once more with DBD off */
                        byte2 = 0;
                        goto again;
                }
                return error;
        }

        poffset = sizeof(scsipi_sense.header);
        poffset += scsipi_sense.header.blk_desc_len;

        if (poffset > sizeof(scsipi_sense) - sizeof(pages->flex_geometry))
                return ERESTART;

        pages = (void *)((u_long)&scsipi_sense + poffset);
#if 0
        {
                size_t i;
                u_int8_t *p;

                printf("page 5 sense:");
                for (i = sizeof(scsipi_sense), p = (void *)&scsipi_sense; i;
                    i--, p++)
                        printf(" %02x", *p);
                printf("\n");
                printf("page 5 pg_code=%d sense=%p/%p\n",
                    pages->flex_geometry.pg_code, &scsipi_sense, pages);
        }
#endif

        if ((pages->flex_geometry.pg_code & PGCODE_MASK) != 5)
                return ERESTART;

        dp->heads = pages->flex_geometry.nheads;
        dp->cyls = _2btol(pages->flex_geometry.ncyl);
        dp->sectors = pages->flex_geometry.ph_sec_tr;
        if (dp->heads == 0 || dp->cyls == 0 || dp->sectors == 0)
                return ERESTART;

        dp->rot_rate = _2btol(pages->rigid_geometry.rpm);
        if (dp->rot_rate == 0)
                dp->rot_rate = 3600;

#if 0
printf("page 5 ok\n");
#endif
        return 0;
}

static int
sd_get_parms(struct sd_softc *sd)
{
        struct disk_parms *dp = &sd->sc_params;
        int error;

        /*
         * If offline, the SDEV_MEDIA_LOADED flag will be
         * cleared by the caller if necessary.
         */
        if (sd->sc_type == T_SIMPLE_DIRECT) {
                error = sd_get_simplifiedparms(sd);
                if (error)
                        return error;
                goto ok;
        }

        error = sd_get_capacity(sd);
        if (error)
                return error;

        if (sd->sc_type == T_OPTICAL)
                goto page0;

        if (sd->sc_flags & FLAGS_REMOVABLE) {
                if (!sd_get_parms_page5(sd, dp) ||
                    !sd_get_parms_page4(sd, dp))
                        goto ok;
        } else {
                if (!sd_get_parms_page4(sd, dp) ||
                    !sd_get_parms_page5(sd, dp))
                        goto ok;
        }

page0:
        printf("fabricating a geometry\n");
        /* Try calling driver's method for figuring out geometry. */
        /*
         * Use adaptec standard fictitious geometry
         * this depends on which controller (e.g. 1542C is
         * different. but we have to put SOMETHING here..)
         */
        dp->heads = 64;
        dp->sectors = 32;
        dp->cyls = dp->disksize / (64 * 32);
        dp->rot_rate = 3600;

ok:
        DPRINTF(("disksize = %" PRId64 ", disksize512 = %" PRId64 ".\n",
            dp->disksize, dp->disksize512));

        return 0;
}

static void
sdgetdefaultlabel(struct sd_softc *sd, struct disklabel *lp)
{

        memset(lp, 0, sizeof(struct disklabel));

        lp->d_secsize = sd->sc_params.blksize;
        lp->d_ntracks = sd->sc_params.heads;
        lp->d_nsectors = sd->sc_params.sectors;
        lp->d_ncylinders = sd->sc_params.cyls;
        lp->d_secpercyl = lp->d_ntracks * lp->d_nsectors;

        lp->d_type = DKTYPE_SCSI;

        strncpy(lp->d_packname, "fictitious", 16);
        lp->d_secperunit = sd->sc_params.disksize;
        lp->d_rpm = sd->sc_params.rot_rate;
        lp->d_interleave = 1;
        lp->d_flags = (sd->sc_flags & FLAGS_REMOVABLE) ? D_REMOVABLE : 0;

        lp->d_partitions[RAW_PART].p_offset = 0;
        lp->d_partitions[RAW_PART].p_size = lp->d_secperunit;
        lp->d_partitions[RAW_PART].p_fstype = FS_UNUSED;
        lp->d_npartitions = RAW_PART + 1;

        lp->d_magic = DISKMAGIC;
        lp->d_magic2 = DISKMAGIC;
        lp->d_checksum = dkcksum(lp);
}

/*
 * Load the label information on the named device.
 */
static int
sdgetdisklabel(struct sd_softc *sd)
{
        struct mbr_sector *mbr;
        struct mbr_partition *mp;
        struct disklabel *lp = &sd->sc_label;
        size_t rsize;
        int sector, i;
        char *msg;
        uint8_t buf[DEV_BSIZE];

        sdgetdefaultlabel(sd, lp);

        if (lp->d_secpercyl == 0) {
                lp->d_secpercyl = 100;
                /* as long as it's not 0 - readdisklabel divides by it (?) */
        }

        /*
         * Find NetBSD Partition in DOS partition table.
         */
        sector = 0;
        if (sdstrategy(sd, F_READ, MBR_BBSECTOR, DEV_BSIZE, buf, &rsize))
                return EOFFSET;

        mbr = (struct mbr_sector *)buf;
        if (mbr->mbr_magic == htole16(MBR_MAGIC)) {
                /*
                 * Lookup NetBSD slice. If there is none, go ahead
                 * and try to read the disklabel off sector #0.
                 */
                mp = mbr->mbr_parts;
                for (i = 0; i < MBR_PART_COUNT; i++) {
                        if (mp[i].mbrp_type == MBR_PTYPE_NETBSD) {
                                sector = le32toh(mp[i].mbrp_start);
                                break;
                        }
                }
        }

        if (sdstrategy(sd, F_READ, sector + LABELSECTOR, DEV_BSIZE,
            buf, &rsize))
                return EOFFSET;

        msg = getdisklabel((const char *)buf + LABELOFFSET, &sd->sc_label);
        if (msg)
                printf("scsi/%d/%d/%d: getdisklabel: %s\n",
                    sd->sc_bus, sd->sc_target, sd->sc_lun, msg);

        /* check partition */
        if ((sd->sc_part >= lp->d_npartitions) ||
            (lp->d_partitions[sd->sc_part].p_fstype == FS_UNUSED)) {
                DPRINTF(("illegal partition\n"));
                return EPART;
        }

        DPRINTF(("label info: d_secsize %d, d_nsectors %d, d_ncylinders %d,"
            " d_ntracks %d, d_secpercyl %d\n",
            sd->sc_label.d_secsize,
            sd->sc_label.d_nsectors,
            sd->sc_label.d_ncylinders,
            sd->sc_label.d_ntracks,
            sd->sc_label.d_secpercyl));

        return 0;
}

/*
 * Open device (read drive parameters and disklabel)
 */
int
sdopen(struct open_file *f, ...)
{
        struct sd_softc *sd;
        struct scsi_test_unit_ready cmd;
        struct scsipi_inquiry_data *inqbuf;
        u_int bus, target, lun, part;
        int error;
        char buf[SCSIPI_INQUIRY_LENGTH_SCSI2];
        va_list ap;

        va_start(ap, f);
        bus = va_arg(ap, u_int);
        target = va_arg(ap, u_int);
        lun = va_arg(ap, u_int);
        part = va_arg(ap, u_int);
        va_end(ap);

        DPRINTF(("sdopen: scsi/%d%d%d/0_%d\n", bus, target, lun, part));

        sd = alloc(sizeof(struct sd_softc));
        if (sd == NULL)
                return ENOMEM;

        memset(sd, 0, sizeof(struct sd_softc));

        sd->sc_part = part;
        sd->sc_lun = lun;
        sd->sc_target = target;
        sd->sc_bus = bus;

        if ((error = scsi_inquire(sd, sizeof(buf), buf)) != 0)
                return error;

        inqbuf = (struct scsipi_inquiry_data *)buf;

        sd->sc_type = inqbuf->device & SID_TYPE;

        /*
         * Determine the operating mode capabilities of the device.
         */
        if ((inqbuf->version & SID_ANSII) >= 2) {
//              if ((inqbuf->flags3 & SID_CmdQue) != 0)
//                      sd->sc_cap |= PERIPH_CAP_TQING;
                if ((inqbuf->flags3 & SID_Sync) != 0)
                        sd->sc_cap |= PERIPH_CAP_SYNC;

                /* SPC-2 */
                if ((inqbuf->version & SID_ANSII) >= 3) {
                        /*
                         * Report ST clocking though CAP_WIDExx/CAP_SYNC.
                         * If the device only supports DT, clear these
                         * flags (DT implies SYNC and WIDE)
                         */
                        switch (inqbuf->flags4 & SID_Clocking) {
                        case SID_CLOCKING_DT_ONLY:
                                sd->sc_cap &= ~PERIPH_CAP_SYNC;
                                break;
                        }
                }
        }
        sd->sc_flags =
            (inqbuf->dev_qual2 & SID_REMOVABLE) ? FLAGS_REMOVABLE : 0;

        memset(&cmd, 0, sizeof(cmd));
        cmd.opcode = SCSI_TEST_UNIT_READY;
        if ((error = scsi_command(sd, (void *)&cmd, sizeof(cmd), NULL, 0)) != 0)
                return error;

        if (sd->sc_flags & FLAGS_REMOVABLE) {
                printf("XXXXX: removable device found. will not support\n");
        }
        if (!(sd->sc_flags & FLAGS_MEDIA_LOADED))
                sd->sc_flags |= FLAGS_MEDIA_LOADED;

        if ((error = sd_get_parms(sd)) != 0)
                return error;

        strncpy(sd->sc_label.d_typename, inqbuf->product, 16);
        if ((error = sdgetdisklabel(sd)) != 0)
                return error;

        f->f_devdata = sd;
        return 0;
}

/*
 * Close device.
 */
int
sdclose(struct open_file *f)
{

        return 0;
}

/*
 * Read some data.
 */
int
sdstrategy(void *f, int rw, daddr_t dblk, size_t size, void *p, size_t *rsize)
{
        struct sd_softc *sd;
        struct disklabel *lp;
        struct partition *pp;
        struct scsipi_generic *cmdp;
        struct scsipi_rw_16 cmd16;
        struct scsipi_rw_10 cmd_big;
        struct scsi_rw_6 cmd_small;
        daddr_t blkno;
        int cmdlen, nsect, i;
        uint8_t *buf;

        if (size == 0)
                return 0;
    
        if (rw != F_READ)
                return EOPNOTSUPP;

        buf = p;
        sd = f;
        lp = &sd->sc_label;
        pp = &lp->d_partitions[sd->sc_part];

        if (!(sd->sc_flags & FLAGS_MEDIA_LOADED))
                return EIO;

        nsect = howmany(size, lp->d_secsize);
        blkno = dblk + pp->p_offset;

        for (i = 0; i < nsect; i++, blkno++) {
                int error;

                /*
                 * Fill out the scsi command.  Use the smallest CDB possible
                 * (6-byte, 10-byte, or 16-byte).
                 */
                if ((blkno & 0x1fffff) == blkno) {
                        /* 6-byte CDB */
                        memset(&cmd_small, 0, sizeof(cmd_small));
                        cmd_small.opcode = SCSI_READ_6_COMMAND;
                        _lto3b(blkno, cmd_small.addr);
                        cmd_small.length = 1;
                        cmdlen = sizeof(cmd_small);
                        cmdp = (struct scsipi_generic *)&cmd_small;
                } else if ((blkno & 0xffffffff) == blkno) {
                        /* 10-byte CDB */
                        memset(&cmd_big, 0, sizeof(cmd_big));
                        cmd_big.opcode = READ_10;
                        _lto4b(blkno, cmd_big.addr);
                        _lto2b(1, cmd_big.length);
                        cmdlen = sizeof(cmd_big);
                        cmdp = (struct scsipi_generic *)&cmd_big;
                } else {
                        /* 16-byte CDB */
                        memset(&cmd16, 0, sizeof(cmd16));
                        cmd16.opcode = READ_16;
                        _lto8b(blkno, cmd16.addr);
                        _lto4b(1, cmd16.length);
                        cmdlen = sizeof(cmd16);
                        cmdp = (struct scsipi_generic *)&cmd16;
                }

                error = scsi_command(sd, cmdp, cmdlen, buf, lp->d_secsize);
                if (error)
                        return error;

                buf += lp->d_secsize;
        }

        *rsize = size;
        return 0;
}