Ok, test10-final is out there now. This has no _known_ bugs that I

[davej-history.git] / drivers / scsi / sr.c

/*
 *  sr.c Copyright (C) 1992 David Giller
 *           Copyright (C) 1993, 1994, 1995, 1999 Eric Youngdale
 *
 *  adapted from:
 *      sd.c Copyright (C) 1992 Drew Eckhardt
 *      Linux scsi disk driver by
 *              Drew Eckhardt <drew@colorado.edu>
 *
 *      Modified by Eric Youngdale ericy@andante.org to
 *      add scatter-gather, multiple outstanding request, and other
 *      enhancements.
 *
 *          Modified by Eric Youngdale eric@andante.org to support loadable
 *          low-level scsi drivers.
 *
 *       Modified by Thomas Quinot thomas@melchior.cuivre.fdn.fr to
 *       provide auto-eject.
 *
 *          Modified by Gerd Knorr <kraxel@cs.tu-berlin.de> to support the
 *          generic cdrom interface
 *
 *       Modified by Jens Axboe <axboe@image.dk> - Uniform sr_packet()
 *       interface, capabilities probe additions, ioctl cleanups, etc.
 *
 *       Modified by Richard Gooch <rgooch@atnf.csiro.au> to support devfs
 *
 *       Modified by Jens Axboe <axboe@suse.de> - support DVD-RAM
 *       transparently and loose the GHOST hack
 *
 *       Modified by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
 *       check resource allocation in sr_init and some cleanups
 *
 */

#include <linux/module.h>

#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/cdrom.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/uaccess.h>

#define MAJOR_NR SCSI_CDROM_MAJOR
#include <linux/blk.h>
#include "scsi.h"
#include "hosts.h"
#include "sr.h"
#include <scsi/scsi_ioctl.h>    /* For the door lock/unlock commands */
#include "constants.h"

#ifdef MODULE
MODULE_PARM(xa_test, "i");      /* see sr_ioctl.c */
#endif

#define MAX_RETRIES     3
#define SR_TIMEOUT      (30 * HZ)

static int sr_init(void);
static void sr_finish(void);
static int sr_attach(Scsi_Device *);
static int sr_detect(Scsi_Device *);
static void sr_detach(Scsi_Device *);

static int sr_init_command(Scsi_Cmnd *);

static struct Scsi_Device_Template sr_template =
{
        name:"cdrom",
        tag:"sr",
        scsi_type:TYPE_ROM,
        major:SCSI_CDROM_MAJOR,
        blk:1,
        detect:sr_detect,
        init:sr_init,
        finish:sr_finish,
        attach:sr_attach,
        detach:sr_detach,
        init_command:sr_init_command
};

Scsi_CD *scsi_CDs;
static int *sr_sizes;

static int *sr_blocksizes;
static int *sr_hardsizes;

static int sr_open(struct cdrom_device_info *, int);
void get_sectorsize(int);
void get_capabilities(int);

static int sr_media_change(struct cdrom_device_info *, int);
static int sr_packet(struct cdrom_device_info *, struct cdrom_generic_command *);

static void sr_release(struct cdrom_device_info *cdi)
{
        if (scsi_CDs[MINOR(cdi->dev)].device->sector_size > 2048)
                sr_set_blocklength(MINOR(cdi->dev), 2048);
        sync_dev(cdi->dev);
        scsi_CDs[MINOR(cdi->dev)].device->access_count--;
        if (scsi_CDs[MINOR(cdi->dev)].device->host->hostt->module)
                __MOD_DEC_USE_COUNT(scsi_CDs[MINOR(cdi->dev)].device->host->hostt->module);
        if (sr_template.module)
                __MOD_DEC_USE_COUNT(sr_template.module);
}

static struct cdrom_device_ops sr_dops =
{
        open:                   sr_open,
        release:                sr_release,
        drive_status:           sr_drive_status,
        media_changed:          sr_media_change,
        tray_move:              sr_tray_move,
        lock_door:              sr_lock_door,
        select_speed:           sr_select_speed,
        get_last_session:       sr_get_last_session,
        get_mcn:                sr_get_mcn,
        reset:                  sr_reset,
        audio_ioctl:            sr_audio_ioctl,
        dev_ioctl:              sr_dev_ioctl,
        capability:             CDC_CLOSE_TRAY | CDC_OPEN_TRAY | CDC_LOCK |
                                CDC_SELECT_SPEED | CDC_SELECT_DISC |
                                CDC_MULTI_SESSION | CDC_MCN |
                                CDC_MEDIA_CHANGED | CDC_PLAY_AUDIO |
                                CDC_RESET | CDC_IOCTLS | CDC_DRIVE_STATUS |
                                CDC_CD_R | CDC_CD_RW | CDC_DVD | CDC_DVD_R |
                                CDC_DVD_RAM | CDC_GENERIC_PACKET,
        generic_packet:         sr_packet,
};

/*
 * This function checks to see if the media has been changed in the
 * CDROM drive.  It is possible that we have already sensed a change,
 * or the drive may have sensed one and not yet reported it.  We must
 * be ready for either case. This function always reports the current
 * value of the changed bit.  If flag is 0, then the changed bit is reset.
 * This function could be done as an ioctl, but we would need to have
 * an inode for that to work, and we do not always have one.
 */

int sr_media_change(struct cdrom_device_info *cdi, int slot)
{
        int retval;

        if (CDSL_CURRENT != slot) {
                /* no changer support */
                return -EINVAL;
        }
        retval = scsi_ioctl(scsi_CDs[MINOR(cdi->dev)].device,
                            SCSI_IOCTL_TEST_UNIT_READY, 0);

        if (retval) {
                /* Unable to test, unit probably not ready.  This usually
                 * means there is no disc in the drive.  Mark as changed,
                 * and we will figure it out later once the drive is
                 * available again.  */

                scsi_CDs[MINOR(cdi->dev)].device->changed = 1;
                return 1;       /* This will force a flush, if called from
                                 * check_disk_change */
        };

        retval = scsi_CDs[MINOR(cdi->dev)].device->changed;
        scsi_CDs[MINOR(cdi->dev)].device->changed = 0;
        /* If the disk changed, the capacity will now be different,
         * so we force a re-read of this information */
        if (retval) {
                /* check multisession offset etc */
                sr_cd_check(cdi);

                /* 
                 * If the disk changed, the capacity will now be different,
                 * so we force a re-read of this information 
                 * Force 2048 for the sector size so that filesystems won't
                 * be trying to use something that is too small if the disc
                 * has changed.
                 */
                scsi_CDs[MINOR(cdi->dev)].needs_sector_size = 1;

                scsi_CDs[MINOR(cdi->dev)].device->sector_size = 2048;
        }
        return retval;
}

/*
 * rw_intr is the interrupt routine for the device driver.  It will be notified on the
 * end of a SCSI read / write, and will take on of several actions based on success or failure.
 */

static void rw_intr(Scsi_Cmnd * SCpnt)
{
        int result = SCpnt->result;
        int this_count = SCpnt->bufflen >> 9;
        int good_sectors = (result == 0 ? this_count : 0);
        int block_sectors = 0;

#ifdef DEBUG
        printk("sr.c done: %x %x\n", result, SCpnt->request.bh->b_data);
#endif
        /*
           Handle MEDIUM ERRORs or VOLUME OVERFLOWs that indicate partial success.
           Since this is a relatively rare error condition, no care is taken to
           avoid unnecessary additional work such as memcpy's that could be avoided.
         */


        if (driver_byte(result) != 0 &&         /* An error occurred */
            SCpnt->sense_buffer[0] == 0xF0 &&   /* Sense data is valid */
            (SCpnt->sense_buffer[2] == MEDIUM_ERROR ||
             SCpnt->sense_buffer[2] == VOLUME_OVERFLOW ||
             SCpnt->sense_buffer[2] == ILLEGAL_REQUEST)) {
                long error_sector = (SCpnt->sense_buffer[3] << 24) |
                (SCpnt->sense_buffer[4] << 16) |
                (SCpnt->sense_buffer[5] << 8) |
                SCpnt->sense_buffer[6];
                int device_nr = DEVICE_NR(SCpnt->request.rq_dev);
                if (SCpnt->request.bh != NULL)
                        block_sectors = SCpnt->request.bh->b_size >> 9;
                if (block_sectors < 4)
                        block_sectors = 4;
                if (scsi_CDs[device_nr].device->sector_size == 2048)
                        error_sector <<= 2;
                error_sector &= ~(block_sectors - 1);
                good_sectors = error_sector - SCpnt->request.sector;
                if (good_sectors < 0 || good_sectors >= this_count)
                        good_sectors = 0;
                /*
                 * The SCSI specification allows for the value returned by READ
                 * CAPACITY to be up to 75 2K sectors past the last readable
                 * block.  Therefore, if we hit a medium error within the last
                 * 75 2K sectors, we decrease the saved size value.
                 */
                if ((error_sector >> 1) < sr_sizes[device_nr] &&
                    scsi_CDs[device_nr].capacity - error_sector < 4 * 75)
                        sr_sizes[device_nr] = error_sector >> 1;
        }
        /*
         * This calls the generic completion function, now that we know
         * how many actual sectors finished, and how many sectors we need
         * to say have failed.
         */
        scsi_io_completion(SCpnt, good_sectors, block_sectors);
}


static request_queue_t *sr_find_queue(kdev_t dev)
{
        /*
         * No such device
         */
        if (MINOR(dev) >= sr_template.dev_max || !scsi_CDs[MINOR(dev)].device)
                return NULL;

        return &scsi_CDs[MINOR(dev)].device->request_queue;
}

static int sr_init_command(Scsi_Cmnd * SCpnt)
{
        int dev, devm, block, this_count;

        devm = MINOR(SCpnt->request.rq_dev);
        dev = DEVICE_NR(SCpnt->request.rq_dev);

        block = SCpnt->request.sector;
        this_count = SCpnt->request_bufflen >> 9;

        if (!SCpnt->request.bh) {
                /*
                 * Umm, yeah, right.   Swapping to a cdrom.  Nice try.
                 */
                return 0;
        }
        SCSI_LOG_HLQUEUE(1, printk("Doing sr request, dev = %d, block = %d\n", devm, block));

        if (dev >= sr_template.nr_dev ||
            !scsi_CDs[dev].device ||
            !scsi_CDs[dev].device->online) {
                SCSI_LOG_HLQUEUE(2, printk("Finishing %ld sectors\n", SCpnt->request.nr_sectors));
                SCSI_LOG_HLQUEUE(2, printk("Retry with 0x%p\n", SCpnt));
                return 0;
        }
        if (scsi_CDs[dev].device->changed) {
                /*
                 * quietly refuse to do anything to a changed disc until the changed
                 * bit has been reset
                 */
                /* printk("SCSI disk has been changed. Prohibiting further I/O.\n"); */
                return 0;
        }
        /*
         * we do lazy blocksize switching (when reading XA sectors,
         * see CDROMREADMODE2 ioctl) 
         */
        if (scsi_CDs[dev].device->sector_size > 2048) {
                if (!in_interrupt())
                        sr_set_blocklength(DEVICE_NR(CURRENT->rq_dev), 2048);
                else
                        printk("sr: can't switch blocksize: in interrupt\n");
        }

        if ((SCpnt->request.cmd == WRITE) && !scsi_CDs[dev].device->writeable)
                return 0;

        if (scsi_CDs[dev].device->sector_size == 1024) {
                if ((block & 1) || (SCpnt->request.nr_sectors & 1)) {
                        printk("sr.c:Bad 1K block number requested (%d %ld)",
                               block, SCpnt->request.nr_sectors);
                        return 0;
                } else {
                        block = block >> 1;
                        this_count = this_count >> 1;
                }
        }
        if (scsi_CDs[dev].device->sector_size == 2048) {
                if ((block & 3) || (SCpnt->request.nr_sectors & 3)) {
                        printk("sr.c:Bad 2K block number requested (%d %ld)",
                               block, SCpnt->request.nr_sectors);
                        return 0;
                } else {
                        block = block >> 2;
                        this_count = this_count >> 2;
                }
        }
        switch (SCpnt->request.cmd) {
        case WRITE:
                SCpnt->cmnd[0] = WRITE_10;
                SCpnt->sc_data_direction = SCSI_DATA_WRITE;
                break;
        case READ:
                SCpnt->cmnd[0] = READ_10;
                SCpnt->sc_data_direction = SCSI_DATA_READ;
                break;
        default:
                panic("Unknown sr command %d\n", SCpnt->request.cmd);
        }

        SCSI_LOG_HLQUEUE(2, printk("sr%d : %s %d/%ld 512 byte blocks.\n",
                                   devm,
                   (SCpnt->request.cmd == WRITE) ? "writing" : "reading",
                                 this_count, SCpnt->request.nr_sectors));

        SCpnt->cmnd[1] = (SCpnt->lun << 5) & 0xe0;

        if (this_count > 0xffff)
                this_count = 0xffff;

        SCpnt->cmnd[2] = (unsigned char) (block >> 24) & 0xff;
        SCpnt->cmnd[3] = (unsigned char) (block >> 16) & 0xff;
        SCpnt->cmnd[4] = (unsigned char) (block >> 8) & 0xff;
        SCpnt->cmnd[5] = (unsigned char) block & 0xff;
        SCpnt->cmnd[6] = SCpnt->cmnd[9] = 0;
        SCpnt->cmnd[7] = (unsigned char) (this_count >> 8) & 0xff;
        SCpnt->cmnd[8] = (unsigned char) this_count & 0xff;

        /*
         * We shouldn't disconnect in the middle of a sector, so with a dumb
         * host adapter, it's safe to assume that we can at least transfer
         * this many bytes between each connect / disconnect.
         */
        SCpnt->transfersize = scsi_CDs[dev].device->sector_size;
        SCpnt->underflow = this_count << 9;

        SCpnt->allowed = MAX_RETRIES;
        SCpnt->timeout_per_command = SR_TIMEOUT;

        /*
         * This is the completion routine we use.  This is matched in terms
         * of capability to this function.
         */
        SCpnt->done = rw_intr;

        /*
         * This indicates that the command is ready from our end to be
         * queued.
         */
        return 1;
}

static int sr_open(struct cdrom_device_info *cdi, int purpose)
{
        check_disk_change(cdi->dev);

        if (MINOR(cdi->dev) >= sr_template.dev_max
            || !scsi_CDs[MINOR(cdi->dev)].device) {
                return -ENXIO;  /* No such device */
        }
        /*
         * If the device is in error recovery, wait until it is done.
         * If the device is offline, then disallow any access to it.
         */
        if (!scsi_block_when_processing_errors(scsi_CDs[MINOR(cdi->dev)].device)) {
                return -ENXIO;
        }
        scsi_CDs[MINOR(cdi->dev)].device->access_count++;
        if (scsi_CDs[MINOR(cdi->dev)].device->host->hostt->module)
                __MOD_INC_USE_COUNT(scsi_CDs[MINOR(cdi->dev)].device->host->hostt->module);
        if (sr_template.module)
                __MOD_INC_USE_COUNT(sr_template.module);

        /* If this device did not have media in the drive at boot time, then
         * we would have been unable to get the sector size.  Check to see if
         * this is the case, and try again.
         */

        if (scsi_CDs[MINOR(cdi->dev)].needs_sector_size)
                get_sectorsize(MINOR(cdi->dev));

        return 0;
}

/*
 * do_sr_request() is the request handler function for the sr driver.
 * Its function in life is to take block device requests, and
 * translate them to SCSI commands.
 */


static int sr_detect(Scsi_Device * SDp)
{

        if (SDp->type != TYPE_ROM && SDp->type != TYPE_WORM)
                return 0;

        printk("Detected scsi CD-ROM sr%d at scsi%d, channel %d, id %d, lun %d\n",
               sr_template.dev_noticed++,
               SDp->host->host_no, SDp->channel, SDp->id, SDp->lun);

        return 1;
}

static int sr_attach(Scsi_Device * SDp)
{
        Scsi_CD *cpnt;
        int i;

        if (SDp->type != TYPE_ROM && SDp->type != TYPE_WORM)
                return 1;

        if (sr_template.nr_dev >= sr_template.dev_max) {
                SDp->attached--;
                return 1;
        }
        for (cpnt = scsi_CDs, i = 0; i < sr_template.dev_max; i++, cpnt++)
                if (!cpnt->device)
                        break;

        if (i >= sr_template.dev_max)
                panic("scsi_devices corrupt (sr)");


        scsi_CDs[i].device = SDp;

        sr_template.nr_dev++;
        if (sr_template.nr_dev > sr_template.dev_max)
                panic("scsi_devices corrupt (sr)");
        return 0;
}


void get_sectorsize(int i)
{
        unsigned char cmd[10];
        unsigned char *buffer;
        int the_result, retries;
        int sector_size;
        Scsi_Request *SRpnt;

        buffer = (unsigned char *) scsi_malloc(512);
        SRpnt = scsi_allocate_request(scsi_CDs[i].device);
        
        if(buffer == NULL || SRpnt == NULL)
        {
                scsi_CDs[i].capacity = 0x1fffff;
                sector_size = 2048;     /* A guess, just in case */
                scsi_CDs[i].needs_sector_size = 1;
                if(buffer)
                        scsi_free(buffer, 512);
                if(SRpnt)
                        scsi_release_request(SRpnt);
                return;
        }       

        retries = 3;
        do {
                cmd[0] = READ_CAPACITY;
                cmd[1] = (scsi_CDs[i].device->lun << 5) & 0xe0;
                memset((void *) &cmd[2], 0, 8);
                SRpnt->sr_request.rq_status = RQ_SCSI_BUSY;     /* Mark as really busy */
                SRpnt->sr_cmd_len = 0;

                memset(buffer, 0, 8);

                /* Do the command and wait.. */

                SRpnt->sr_data_direction = SCSI_DATA_READ;
                scsi_wait_req(SRpnt, (void *) cmd, (void *) buffer,
                              8, SR_TIMEOUT, MAX_RETRIES);

                the_result = SRpnt->sr_result;
                retries--;

        } while (the_result && retries);


        scsi_release_request(SRpnt);
        SRpnt = NULL;

        if (the_result) {
                scsi_CDs[i].capacity = 0x1fffff;
                sector_size = 2048;     /* A guess, just in case */
                scsi_CDs[i].needs_sector_size = 1;
        } else {
#if 0
                if (cdrom_get_last_written(MKDEV(MAJOR_NR, i),
                                         (long *) &scsi_CDs[i].capacity))
#endif
                        scsi_CDs[i].capacity = 1 + ((buffer[0] << 24) |
                                                    (buffer[1] << 16) |
                                                    (buffer[2] << 8) |
                                                    buffer[3]);
                sector_size = (buffer[4] << 24) |
                    (buffer[5] << 16) | (buffer[6] << 8) | buffer[7];
                switch (sector_size) {
                        /*
                         * HP 4020i CD-Recorder reports 2340 byte sectors
                         * Philips CD-Writers report 2352 byte sectors
                         *
                         * Use 2k sectors for them..
                         */
                case 0:
                case 2340:
                case 2352:
                        sector_size = 2048;
                        /* fall through */
                case 2048:
                        scsi_CDs[i].capacity *= 4;
                        /* fall through */
                case 512:
                        break;
                default:
                        printk("sr%d: unsupported sector size %d.\n",
                               i, sector_size);
                        scsi_CDs[i].capacity = 0;
                        scsi_CDs[i].needs_sector_size = 1;
                }

                scsi_CDs[i].device->sector_size = sector_size;

                /*
                 * Add this so that we have the ability to correctly gauge
                 * what the device is capable of.
                 */
                scsi_CDs[i].needs_sector_size = 0;
                sr_sizes[i] = scsi_CDs[i].capacity >> (BLOCK_SIZE_BITS - 9);
        };
        scsi_free(buffer, 512);
}

void get_capabilities(int i)
{
        unsigned char cmd[6];
        unsigned char *buffer;
        int rc, n;

        static char *loadmech[] =
        {
                "caddy",
                "tray",
                "pop-up",
                "",
                "changer",
                "cartridge changer",
                "",
                ""
        };

        buffer = (unsigned char *) scsi_malloc(512);
        cmd[0] = MODE_SENSE;
        cmd[1] = (scsi_CDs[i].device->lun << 5) & 0xe0;
        cmd[2] = 0x2a;
        cmd[4] = 128;
        cmd[3] = cmd[5] = 0;
        rc = sr_do_ioctl(i, cmd, buffer, 128, 1, SCSI_DATA_READ);

        if (-EINVAL == rc) {
                /* failed, drive has'nt this mode page */
                scsi_CDs[i].cdi.speed = 1;
                /* disable speed select, drive probably can't do this either */
                scsi_CDs[i].cdi.mask |= CDC_SELECT_SPEED;
                scsi_free(buffer, 512);
                return;
        }
        n = buffer[3] + 4;
        scsi_CDs[i].cdi.speed = ((buffer[n + 8] << 8) + buffer[n + 9]) / 176;
        scsi_CDs[i].readcd_known = 1;
        scsi_CDs[i].readcd_cdda = buffer[n + 5] & 0x01;
        /* print some capability bits */
        printk("sr%i: scsi3-mmc drive: %dx/%dx %s%s%s%s%s%s\n", i,
               ((buffer[n + 14] << 8) + buffer[n + 15]) / 176,
               scsi_CDs[i].cdi.speed,
               buffer[n + 3] & 0x01 ? "writer " : "",   /* CD Writer */
               buffer[n + 3] & 0x20 ? "dvd-ram " : "",
               buffer[n + 2] & 0x02 ? "cd/rw " : "",    /* can read rewriteable */
               buffer[n + 4] & 0x20 ? "xa/form2 " : "",         /* can read xa/from2 */
               buffer[n + 5] & 0x01 ? "cdda " : "",     /* can read audio data */
               loadmech[buffer[n + 6] >> 5]);
        if ((buffer[n + 6] >> 5) == 0)
                /* caddy drives can't close tray... */
                scsi_CDs[i].cdi.mask |= CDC_CLOSE_TRAY;
        if ((buffer[n + 2] & 0x8) == 0)
                /* not a DVD drive */
                scsi_CDs[i].cdi.mask |= CDC_DVD;
        if ((buffer[n + 3] & 0x20) == 0) {
                /* can't write DVD-RAM media */
                scsi_CDs[i].cdi.mask |= CDC_DVD_RAM;
        } else {
                scsi_CDs[i].device->writeable = 1;
        }
        if ((buffer[n + 3] & 0x10) == 0)
                /* can't write DVD-R media */
                scsi_CDs[i].cdi.mask |= CDC_DVD_R;
        if ((buffer[n + 3] & 0x2) == 0)
                /* can't write CD-RW media */
                scsi_CDs[i].cdi.mask |= CDC_CD_RW;
        if ((buffer[n + 3] & 0x1) == 0)
                /* can't write CD-R media */
                scsi_CDs[i].cdi.mask |= CDC_CD_R;
        if ((buffer[n + 6] & 0x8) == 0)
                /* can't eject */
                scsi_CDs[i].cdi.mask |= CDC_OPEN_TRAY;

        if ((buffer[n + 6] >> 5) == mechtype_individual_changer ||
            (buffer[n + 6] >> 5) == mechtype_cartridge_changer)
                scsi_CDs[i].cdi.capacity =
                    cdrom_number_of_slots(&(scsi_CDs[i].cdi));
        if (scsi_CDs[i].cdi.capacity <= 1)
                /* not a changer */
                scsi_CDs[i].cdi.mask |= CDC_SELECT_DISC;
        /*else    I don't think it can close its tray
           scsi_CDs[i].cdi.mask |= CDC_CLOSE_TRAY; */

        scsi_free(buffer, 512);
}

/*
 * sr_packet() is the entry point for the generic commands generated
 * by the Uniform CD-ROM layer. 
 */
static int sr_packet(struct cdrom_device_info *cdi, struct cdrom_generic_command *cgc)
{
        Scsi_Request *SRpnt;
        Scsi_Device *device = scsi_CDs[MINOR(cdi->dev)].device;
        unsigned char *buffer = cgc->buffer;
        int buflen;

        /* get the device */
        SRpnt = scsi_allocate_request(device);
        if (SRpnt == NULL)
                return -ENODEV; /* this just doesn't seem right /axboe */

        /* use buffer for ISA DMA */
        buflen = (cgc->buflen + 511) & ~511;
        if (cgc->buffer && SRpnt->sr_host->unchecked_isa_dma &&
            (virt_to_phys(cgc->buffer) + cgc->buflen - 1 > ISA_DMA_THRESHOLD)) {
                buffer = scsi_malloc(buflen);
                if (buffer == NULL) {
                        printk("sr: SCSI DMA pool exhausted.");
                        return -ENOMEM;
                }
                memcpy(buffer, cgc->buffer, cgc->buflen);
        }
        /* set the LUN */
        cgc->cmd[1] |= device->lun << 5;

        /* do the locking and issue the command */
        SRpnt->sr_request.rq_dev = cdi->dev;
        /* scsi_wait_req sets the command length */
        SRpnt->sr_cmd_len = 0;

        SRpnt->sr_data_direction = cgc->data_direction;
        scsi_wait_req(SRpnt, (void *) cgc->cmd, (void *) buffer, cgc->buflen,
                      SR_TIMEOUT, MAX_RETRIES);

        if ((cgc->stat = SRpnt->sr_result))
                cgc->sense = (struct request_sense *) SRpnt->sr_sense_buffer;

        /* release */
        SRpnt->sr_request.rq_dev = MKDEV(0, 0);
        scsi_release_request(SRpnt);
        SRpnt = NULL;

        /* write DMA buffer back if used */
        if (buffer && (buffer != cgc->buffer)) {
                memcpy(cgc->buffer, buffer, cgc->buflen);
                scsi_free(buffer, buflen);
        }


        return cgc->stat;
}

static int sr_registered;

static int sr_init()
{
        int i;

        if (sr_template.dev_noticed == 0)
                return 0;

        if (!sr_registered) {
                if (devfs_register_blkdev(MAJOR_NR, "sr", &cdrom_fops)) {
                        printk("Unable to get major %d for SCSI-CD\n", MAJOR_NR);
                        return 1;
                }
                sr_registered++;
        }
        if (scsi_CDs)
                return 0;

        sr_template.dev_max = sr_template.dev_noticed + SR_EXTRA_DEVS;
        scsi_CDs = kmalloc(sr_template.dev_max * sizeof(Scsi_CD), GFP_ATOMIC);
        if (!scsi_CDs)
                goto cleanup_devfs;
        memset(scsi_CDs, 0, sr_template.dev_max * sizeof(Scsi_CD));

        sr_sizes = kmalloc(sr_template.dev_max * sizeof(int), GFP_ATOMIC);
        if (!sr_sizes)
                goto cleanup_cds;
        memset(sr_sizes, 0, sr_template.dev_max * sizeof(int));

        sr_blocksizes = kmalloc(sr_template.dev_max * sizeof(int), GFP_ATOMIC);
        if (!sr_blocksizes)
                goto cleanup_sizes;

        sr_hardsizes = kmalloc(sr_template.dev_max * sizeof(int), GFP_ATOMIC);
        if (!sr_hardsizes)
                goto cleanup_blocksizes;
        /*
         * These are good guesses for the time being.
         */
        for (i = 0; i < sr_template.dev_max; i++) {
                sr_blocksizes[i] = 2048;
                sr_hardsizes[i] = 2048;
        }
        blksize_size[MAJOR_NR] = sr_blocksizes;
        hardsect_size[MAJOR_NR] = sr_hardsizes;
        return 0;
cleanup_blocksizes:
        kfree(sr_blocksizes);
cleanup_sizes:
        kfree(sr_sizes);
cleanup_cds:
        kfree(scsi_CDs);
cleanup_devfs:
        devfs_unregister_blkdev(MAJOR_NR, "sr");
        sr_registered--;
        return 1;
}

void sr_finish()
{
        int i;
        char name[6];

        blk_dev[MAJOR_NR].queue = sr_find_queue;
        blk_size[MAJOR_NR] = sr_sizes;

        for (i = 0; i < sr_template.nr_dev; ++i) {
                /* If we have already seen this, then skip it.  Comes up
                 * with loadable modules. */
                if (scsi_CDs[i].capacity)
                        continue;
                scsi_CDs[i].capacity = 0x1fffff;
                scsi_CDs[i].device->sector_size = 2048;         /* A guess, just in case */
                scsi_CDs[i].needs_sector_size = 1;
                scsi_CDs[i].device->changed = 1;        /* force recheck CD type */
#if 0
                /* seems better to leave this for later */
                get_sectorsize(i);
                printk("Scd sectorsize = %d bytes.\n", scsi_CDs[i].sector_size);
#endif
                scsi_CDs[i].use = 1;

                scsi_CDs[i].device->ten = 1;
                scsi_CDs[i].device->remap = 1;
                scsi_CDs[i].readcd_known = 0;
                scsi_CDs[i].readcd_cdda = 0;
                sr_sizes[i] = scsi_CDs[i].capacity >> (BLOCK_SIZE_BITS - 9);

                scsi_CDs[i].cdi.ops = &sr_dops;
                scsi_CDs[i].cdi.handle = &scsi_CDs[i];
                scsi_CDs[i].cdi.dev = MKDEV(MAJOR_NR, i);
                scsi_CDs[i].cdi.mask = 0;
                scsi_CDs[i].cdi.capacity = 1;
                get_capabilities(i);
                sr_vendor_init(i);

                sprintf(name, "sr%d", i);
                strcpy(scsi_CDs[i].cdi.name, name);
                scsi_CDs[i].cdi.de =
                    devfs_register (scsi_CDs[i].device->de, "cd",
                                    DEVFS_FL_DEFAULT, MAJOR_NR, i,
                                    S_IFBLK | S_IRUGO | S_IWUGO,
                                    &cdrom_fops, NULL);
                register_cdrom(&scsi_CDs[i].cdi);
        }


        /* If our host adapter is capable of scatter-gather, then we increase
         * the read-ahead to 16 blocks (32 sectors).  If not, we use
         * a two block (4 sector) read ahead. */
        if (scsi_CDs[0].device && scsi_CDs[0].device->host->sg_tablesize)
                read_ahead[MAJOR_NR] = 32;      /* 32 sector read-ahead.  Always removable. */
        else
                read_ahead[MAJOR_NR] = 4;       /* 4 sector read-ahead */

        return;
}

static void sr_detach(Scsi_Device * SDp)
{
        Scsi_CD *cpnt;
        int i;

        for (cpnt = scsi_CDs, i = 0; i < sr_template.dev_max; i++, cpnt++)
                if (cpnt->device == SDp) {
                        kdev_t devi = MKDEV(MAJOR_NR, i);
                        struct super_block *sb = get_super(devi);

                        /*
                         * Since the cdrom is read-only, no need to sync the device.
                         * We should be kind to our buffer cache, however.
                         */
                        if (sb)
                                invalidate_inodes(sb);
                        invalidate_buffers(devi);

                        /*
                         * Reset things back to a sane state so that one can re-load a new
                         * driver (perhaps the same one).
                         */
                        unregister_cdrom(&(cpnt->cdi));
                        cpnt->device = NULL;
                        cpnt->capacity = 0;
                        SDp->attached--;
                        sr_template.nr_dev--;
                        sr_template.dev_noticed--;
                        sr_sizes[i] = 0;
                        return;
                }
        return;
}

static int __init init_sr(void)
{
        sr_template.module = THIS_MODULE;
        return scsi_register_module(MODULE_SCSI_DEV, &sr_template);
}

static void __exit exit_sr(void)
{
        scsi_unregister_module(MODULE_SCSI_DEV, &sr_template);
        devfs_unregister_blkdev(MAJOR_NR, "sr");
        sr_registered--;
        if (scsi_CDs != NULL) {
                kfree(scsi_CDs);

                kfree(sr_sizes);
                sr_sizes = NULL;

                kfree(sr_blocksizes);
                sr_blocksizes = NULL;
                kfree(sr_hardsizes);
                sr_hardsizes = NULL;
        }
        blksize_size[MAJOR_NR] = NULL;
        hardsect_size[MAJOR_NR] = NULL;
        blk_size[MAJOR_NR] = NULL;
        read_ahead[MAJOR_NR] = 0;

        sr_template.dev_max = 0;
}

module_init(init_sr);
module_exit(exit_sr);