/*
   * SCSI Media Changer device driver for Linux 2.6
   *
   *     (c) 1996-2003 Gerd Knorr <kraxel@bytesex.org>
   *
   */
  
  #define VERSION "0.25"

  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/fs.h>
  #include <linux/kernel.h>

  #include <linux/mm.h>
  #include <linux/major.h>
  #include <linux/string.h>
  #include <linux/errno.h>
  #include <linux/interrupt.h>
  #include <linux/blkdev.h>
  #include <linux/completion.h>

  #include <linux/compat.h>
  #include <linux/chio.h>			/* here are all the ioctls */

  #include <linux/mutex.h>

  #include <linux/idr.h>

  #include <linux/smp_lock.h>

  #include <linux/slab.h>

  
  #include <scsi/scsi.h>
  #include <scsi/scsi_cmnd.h>
  #include <scsi/scsi_driver.h>
  #include <scsi/scsi_ioctl.h>
  #include <scsi/scsi_host.h>
  #include <scsi/scsi_device.h>

  #include <scsi/scsi_eh.h>

  #include <scsi/scsi_dbg.h>
  
  #define CH_DT_MAX       16
  #define CH_TYPES        8

  #define CH_MAX_DEVS     128

  
  MODULE_DESCRIPTION("device driver for scsi media changer devices");
  MODULE_AUTHOR("Gerd Knorr <kraxel@bytesex.org>");
  MODULE_LICENSE("GPL");

  MODULE_ALIAS_CHARDEV_MAJOR(SCSI_CHANGER_MAJOR);

  MODULE_ALIAS_SCSI_DEVICE(TYPE_MEDIUM_CHANGER);

  
  static int init = 1;
  module_param(init, int, 0444);
  MODULE_PARM_DESC(init, \
      "initialize element status on driver load (default: on)");
  
  static int timeout_move = 300;
  module_param(timeout_move, int, 0644);
  MODULE_PARM_DESC(timeout_move,"timeout for move commands "
  		 "(default: 300 seconds)");
  
  static int timeout_init = 3600;
  module_param(timeout_init, int, 0644);
  MODULE_PARM_DESC(timeout_init,"timeout for INITIALIZE ELEMENT STATUS "
  		 "(default: 3600 seconds)");
  
  static int verbose = 1;
  module_param(verbose, int, 0644);
  MODULE_PARM_DESC(verbose,"be verbose (default: on)");
  
  static int debug = 0;
  module_param(debug, int, 0644);
  MODULE_PARM_DESC(debug,"enable/disable debug messages, also prints more "
  		 "detailed sense codes on scsi errors (default: off)");
  
  static int dt_id[CH_DT_MAX] = { [ 0 ... (CH_DT_MAX-1) ] = -1 };
  static int dt_lun[CH_DT_MAX];
  module_param_array(dt_id,  int, NULL, 0444);
  module_param_array(dt_lun, int, NULL, 0444);
  
  /* tell the driver about vendor-specific slots */
  static int vendor_firsts[CH_TYPES-4];
  static int vendor_counts[CH_TYPES-4];
  module_param_array(vendor_firsts, int, NULL, 0444);
  module_param_array(vendor_counts, int, NULL, 0444);

  static const char * vendor_labels[CH_TYPES-4] = {

  	"v0", "v1", "v2", "v3"
  };
  // module_param_string_array(vendor_labels, NULL, 0444);

  #define DPRINTK(fmt, arg...)						\
  do {									\
  	if (debug)							\
  		printk(KERN_DEBUG "%s: " fmt, ch->name, ##arg);		\
  } while (0)
  #define VPRINTK(level, fmt, arg...)					\
  do {									\
  	if (verbose)							\
  		printk(level "%s: " fmt, ch->name, ##arg);		\
  } while (0)

  
  /* ------------------------------------------------------------------- */
  
  #define MAX_RETRIES   1

  static struct class * ch_sysfs_class;

  
  typedef struct {
  	struct list_head    list;
  	int                 minor;
  	char                name[8];
  	struct scsi_device  *device;
  	struct scsi_device  **dt;        /* ptrs to data transfer elements */
  	u_int               firsts[CH_TYPES];
  	u_int               counts[CH_TYPES];
  	u_int               unit_attention;
  	u_int		    voltags;

  	struct mutex	    lock;

  } scsi_changer;

  static DEFINE_IDR(ch_index_idr);
  static DEFINE_SPINLOCK(ch_index_lock);

  static const struct {

  	unsigned char  sense;
  	unsigned char  asc;
  	unsigned char  ascq;
  	int	       errno;

  } ch_err[] = {

  /* Just filled in what looks right. Hav'nt checked any standard paper for
     these errno assignments, so they may be wrong... */
  	{
  		.sense  = ILLEGAL_REQUEST,
  		.asc    = 0x21,
  		.ascq   = 0x01,
  		.errno  = EBADSLT, /* Invalid element address */
  	},{
  		.sense  = ILLEGAL_REQUEST,
  		.asc    = 0x28,
  		.ascq   = 0x01,
  		.errno  = EBADE,   /* Import or export element accessed */
  	},{
  		.sense  = ILLEGAL_REQUEST,
  		.asc    = 0x3B,
  		.ascq   = 0x0D,
  		.errno  = EXFULL,  /* Medium destination element full */
  	},{
  		.sense  = ILLEGAL_REQUEST,
  		.asc    = 0x3B,
  		.ascq   = 0x0E,
  		.errno  = EBADE,   /* Medium source element empty */
  	},{
  		.sense  = ILLEGAL_REQUEST,
  		.asc    = 0x20,
  		.ascq   = 0x00,
  		.errno  = EBADRQC, /* Invalid command operation code */
  	},{
  	        /* end of list */
  	}
  };
  
  /* ------------------------------------------------------------------- */

  static int ch_find_errno(struct scsi_sense_hdr *sshdr)

  {
  	int i,errno = 0;
  
  	/* Check to see if additional sense information is available */

  	if (scsi_sense_valid(sshdr) &&
  	    sshdr->asc != 0) {

  		for (i = 0; ch_err[i].errno != 0; i++) {
  			if (ch_err[i].sense == sshdr->sense_key &&
  			    ch_err[i].asc   == sshdr->asc &&
  			    ch_err[i].ascq  == sshdr->ascq) {
  				errno = -ch_err[i].errno;

  				break;
  			}
  		}
  	}
  	if (errno == 0)
  		errno = -EIO;
  	return errno;
  }
  
  static int
  ch_do_scsi(scsi_changer *ch, unsigned char *cmd,
  	   void *buffer, unsigned buflength,
  	   enum dma_data_direction direction)
  {

  	int errno, retries = 0, timeout, result;
  	struct scsi_sense_hdr sshdr;

  	timeout = (cmd[0] == INITIALIZE_ELEMENT_STATUS)
  		? timeout_init : timeout_move;
  
   retry:
  	errno = 0;
  	if (debug) {

  		DPRINTK("command: ");

  		__scsi_print_command(cmd);
  	}

          result = scsi_execute_req(ch->device, cmd, direction, buffer,
  				  buflength, &sshdr, timeout * HZ,

  				  MAX_RETRIES, NULL);

  	DPRINTK("result: 0x%x
  ",result);

  	if (driver_byte(result) & DRIVER_SENSE) {

  		if (debug)

  			scsi_print_sense_hdr(ch->name, &sshdr);
  		errno = ch_find_errno(&sshdr);

  		switch(sshdr.sense_key) {

  		case UNIT_ATTENTION:
  			ch->unit_attention = 1;
  			if (retries++ < 3)
  				goto retry;
  			break;
  		}
  	}

  	return errno;
  }
  
  /* ------------------------------------------------------------------------ */
  
  static int
  ch_elem_to_typecode(scsi_changer *ch, u_int elem)
  {
  	int i;

  	for (i = 0; i < CH_TYPES; i++) {
  		if (elem >= ch->firsts[i]  &&
  		    elem <  ch->firsts[i] +
  	            ch->counts[i])
  			return i+1;
  	}
  	return 0;
  }
  
  static int
  ch_read_element_status(scsi_changer *ch, u_int elem, char *data)
  {
  	u_char  cmd[12];
  	u_char  *buffer;
  	int     result;

  	buffer = kmalloc(512, GFP_KERNEL | GFP_DMA);
  	if(!buffer)
  		return -ENOMEM;

   retry:
  	memset(cmd,0,sizeof(cmd));
  	cmd[0] = READ_ELEMENT_STATUS;

  	cmd[1] = (ch->device->lun << 5) |

  		(ch->voltags ? 0x10 : 0) |
  		ch_elem_to_typecode(ch,elem);
  	cmd[2] = (elem >> 8) & 0xff;
  	cmd[3] = elem        & 0xff;
  	cmd[5] = 1;
  	cmd[9] = 255;
  	if (0 == (result = ch_do_scsi(ch, cmd, buffer, 256, DMA_FROM_DEVICE))) {
  		if (((buffer[16] << 8) | buffer[17]) != elem) {

  			DPRINTK("asked for element 0x%02x, got 0x%02x
  ",

  				elem,(buffer[16] << 8) | buffer[17]);
  			kfree(buffer);
  			return -EIO;
  		}
  		memcpy(data,buffer+16,16);
  	} else {
  		if (ch->voltags) {
  			ch->voltags = 0;

  			VPRINTK(KERN_INFO, "device has no volume tag support
  ");

  			goto retry;
  		}

  		DPRINTK("READ ELEMENT STATUS for element 0x%x failed
  ",elem);

  	}
  	kfree(buffer);
  	return result;
  }

  static int

  ch_init_elem(scsi_changer *ch)
  {
  	int err;
  	u_char cmd[6];

  	VPRINTK(KERN_INFO, "INITIALIZE ELEMENT STATUS, may take some time ...
  ");

  	memset(cmd,0,sizeof(cmd));
  	cmd[0] = INITIALIZE_ELEMENT_STATUS;
  	cmd[1] = ch->device->lun << 5;
  	err = ch_do_scsi(ch, cmd, NULL, 0, DMA_NONE);

  	VPRINTK(KERN_INFO, "... finished
  ");

  	return err;
  }
  
  static int
  ch_readconfig(scsi_changer *ch)
  {
  	u_char  cmd[10], data[16];
  	u_char  *buffer;
  	int     result,id,lun,i;
  	u_int   elem;

  	buffer = kzalloc(512, GFP_KERNEL | GFP_DMA);

  	if (!buffer)
  		return -ENOMEM;

  	memset(cmd,0,sizeof(cmd));
  	cmd[0] = MODE_SENSE;
  	cmd[1] = ch->device->lun << 5;
  	cmd[2] = 0x1d;
  	cmd[4] = 255;
  	result = ch_do_scsi(ch, cmd, buffer, 255, DMA_FROM_DEVICE);
  	if (0 != result) {
  		cmd[1] |= (1<<3);
  		result  = ch_do_scsi(ch, cmd, buffer, 255, DMA_FROM_DEVICE);
  	}
  	if (0 == result) {
  		ch->firsts[CHET_MT] =
  			(buffer[buffer[3]+ 6] << 8) | buffer[buffer[3]+ 7];
  		ch->counts[CHET_MT] =
  			(buffer[buffer[3]+ 8] << 8) | buffer[buffer[3]+ 9];
  		ch->firsts[CHET_ST] =
  			(buffer[buffer[3]+10] << 8) | buffer[buffer[3]+11];
  		ch->counts[CHET_ST] =
  			(buffer[buffer[3]+12] << 8) | buffer[buffer[3]+13];
  		ch->firsts[CHET_IE] =
  			(buffer[buffer[3]+14] << 8) | buffer[buffer[3]+15];
  		ch->counts[CHET_IE] =
  			(buffer[buffer[3]+16] << 8) | buffer[buffer[3]+17];
  		ch->firsts[CHET_DT] =
  			(buffer[buffer[3]+18] << 8) | buffer[buffer[3]+19];
  		ch->counts[CHET_DT] =
  			(buffer[buffer[3]+20] << 8) | buffer[buffer[3]+21];

  		VPRINTK(KERN_INFO, "type #1 (mt): 0x%x+%d [medium transport]
  ",

  			ch->firsts[CHET_MT],
  			ch->counts[CHET_MT]);

  		VPRINTK(KERN_INFO, "type #2 (st): 0x%x+%d [storage]
  ",

  			ch->firsts[CHET_ST],
  			ch->counts[CHET_ST]);

  		VPRINTK(KERN_INFO, "type #3 (ie): 0x%x+%d [import/export]
  ",

  			ch->firsts[CHET_IE],
  			ch->counts[CHET_IE]);

  		VPRINTK(KERN_INFO, "type #4 (dt): 0x%x+%d [data transfer]
  ",

  			ch->firsts[CHET_DT],
  			ch->counts[CHET_DT]);
  	} else {

  		VPRINTK(KERN_INFO, "reading element address assigment page failed!
  ");

  	}

  	/* vendor specific element types */
  	for (i = 0; i < 4; i++) {
  		if (0 == vendor_counts[i])
  			continue;
  		if (NULL == vendor_labels[i])
  			continue;
  		ch->firsts[CHET_V1+i] = vendor_firsts[i];
  		ch->counts[CHET_V1+i] = vendor_counts[i];

  		VPRINTK(KERN_INFO, "type #%d (v%d): 0x%x+%d [%s, vendor specific]
  ",

  			i+5,i+1,vendor_firsts[i],vendor_counts[i],
  			vendor_labels[i]);
  	}
  
  	/* look up the devices of the data transfer elements */

  	ch->dt = kcalloc(ch->counts[CHET_DT], sizeof(*ch->dt),

  			 GFP_KERNEL);

  
  	if (!ch->dt) {
  		kfree(buffer);
  		return -ENOMEM;
  	}

  	for (elem = 0; elem < ch->counts[CHET_DT]; elem++) {
  		id  = -1;
  		lun = 0;
  		if (elem < CH_DT_MAX  &&  -1 != dt_id[elem]) {
  			id  = dt_id[elem];
  			lun = dt_lun[elem];

  			VPRINTK(KERN_INFO, "dt 0x%x: [insmod option] ",

  				elem+ch->firsts[CHET_DT]);
  		} else if (0 != ch_read_element_status
  			   (ch,elem+ch->firsts[CHET_DT],data)) {

  			VPRINTK(KERN_INFO, "dt 0x%x: READ ELEMENT STATUS failed
  ",

  				elem+ch->firsts[CHET_DT]);
  		} else {

  			VPRINTK(KERN_INFO, "dt 0x%x: ",elem+ch->firsts[CHET_DT]);

  			if (data[6] & 0x80) {

  				VPRINTK(KERN_CONT, "not this SCSI bus
  ");

  				ch->dt[elem] = NULL;
  			} else if (0 == (data[6] & 0x30)) {

  				VPRINTK(KERN_CONT, "ID/LUN unknown
  ");

  				ch->dt[elem] = NULL;
  			} else {
  				id  = ch->device->id;
  				lun = 0;
  				if (data[6] & 0x20) id  = data[7];
  				if (data[6] & 0x10) lun = data[6] & 7;
  			}
  		}
  		if (-1 != id) {

  			VPRINTK(KERN_CONT, "ID %i, LUN %i, ",id,lun);

  			ch->dt[elem] =
  				scsi_device_lookup(ch->device->host,
  						   ch->device->channel,
  						   id,lun);
  			if (!ch->dt[elem]) {
  				/* should not happen */

  				VPRINTK(KERN_CONT, "Huh? device not found!
  ");

  			} else {

  				VPRINTK(KERN_CONT, "name: %8.8s %16.16s %4.4s
  ",
  					ch->dt[elem]->vendor,
  					ch->dt[elem]->model,
  					ch->dt[elem]->rev);

  			}
  		}
  	}
  	ch->voltags = 1;
  	kfree(buffer);
  
  	return 0;
  }
  
  /* ------------------------------------------------------------------------ */
  
  static int
  ch_position(scsi_changer *ch, u_int trans, u_int elem, int rotate)
  {
  	u_char  cmd[10];

  	DPRINTK("position: 0x%x
  ",elem);

  	if (0 == trans)
  		trans = ch->firsts[CHET_MT];
  	memset(cmd,0,sizeof(cmd));
  	cmd[0]  = POSITION_TO_ELEMENT;
  	cmd[1]  = ch->device->lun << 5;
  	cmd[2]  = (trans >> 8) & 0xff;
  	cmd[3]  =  trans       & 0xff;
  	cmd[4]  = (elem  >> 8) & 0xff;
  	cmd[5]  =  elem        & 0xff;
  	cmd[8]  = rotate ? 1 : 0;
  	return ch_do_scsi(ch, cmd, NULL, 0, DMA_NONE);
  }
  
  static int
  ch_move(scsi_changer *ch, u_int trans, u_int src, u_int dest, int rotate)
  {
  	u_char  cmd[12];

  	DPRINTK("move: 0x%x => 0x%x
  ",src,dest);

  	if (0 == trans)
  		trans = ch->firsts[CHET_MT];
  	memset(cmd,0,sizeof(cmd));
  	cmd[0]  = MOVE_MEDIUM;
  	cmd[1]  = ch->device->lun << 5;
  	cmd[2]  = (trans >> 8) & 0xff;
  	cmd[3]  =  trans       & 0xff;
  	cmd[4]  = (src   >> 8) & 0xff;
  	cmd[5]  =  src         & 0xff;
  	cmd[6]  = (dest  >> 8) & 0xff;
  	cmd[7]  =  dest        & 0xff;
  	cmd[10] = rotate ? 1 : 0;
  	return ch_do_scsi(ch, cmd, NULL,0, DMA_NONE);
  }
  
  static int
  ch_exchange(scsi_changer *ch, u_int trans, u_int src,
  	    u_int dest1, u_int dest2, int rotate1, int rotate2)
  {
  	u_char  cmd[12];

  	DPRINTK("exchange: 0x%x => 0x%x => 0x%x
  ",

  		src,dest1,dest2);
  	if (0 == trans)
  		trans = ch->firsts[CHET_MT];
  	memset(cmd,0,sizeof(cmd));
  	cmd[0]  = EXCHANGE_MEDIUM;
  	cmd[1]  = ch->device->lun << 5;
  	cmd[2]  = (trans >> 8) & 0xff;
  	cmd[3]  =  trans       & 0xff;
  	cmd[4]  = (src   >> 8) & 0xff;
  	cmd[5]  =  src         & 0xff;
  	cmd[6]  = (dest1 >> 8) & 0xff;
  	cmd[7]  =  dest1       & 0xff;
  	cmd[8]  = (dest2 >> 8) & 0xff;
  	cmd[9]  =  dest2       & 0xff;
  	cmd[10] = (rotate1 ? 1 : 0) | (rotate2 ? 2 : 0);

  	return ch_do_scsi(ch, cmd, NULL,0, DMA_NONE);
  }
  
  static void
  ch_check_voltag(char *tag)
  {
  	int i;
  
  	for (i = 0; i < 32; i++) {
  		/* restrict to ascii */
  		if (tag[i] >= 0x7f || tag[i] < 0x20)
  			tag[i] = ' ';
  		/* don't allow search wildcards */
  		if (tag[i] == '?' ||
  		    tag[i] == '*')
  			tag[i] = ' ';
  	}
  }
  
  static int
  ch_set_voltag(scsi_changer *ch, u_int elem,
  	      int alternate, int clear, u_char *tag)
  {
  	u_char  cmd[12];
  	u_char  *buffer;
  	int result;

  	buffer = kzalloc(512, GFP_KERNEL);

  	if (!buffer)
  		return -ENOMEM;

  	DPRINTK("%s %s voltag: 0x%x => \"%s\"
  ",

  		clear     ? "clear"     : "set",
  		alternate ? "alternate" : "primary",
  		elem, tag);
  	memset(cmd,0,sizeof(cmd));
  	cmd[0]  = SEND_VOLUME_TAG;

  	cmd[1] = (ch->device->lun << 5) |

  		ch_elem_to_typecode(ch,elem);
  	cmd[2] = (elem >> 8) & 0xff;
  	cmd[3] = elem        & 0xff;
  	cmd[5] = clear
  		? (alternate ? 0x0d : 0x0c)
  		: (alternate ? 0x0b : 0x0a);

  	cmd[9] = 255;
  
  	memcpy(buffer,tag,32);
  	ch_check_voltag(buffer);
  
  	result = ch_do_scsi(ch, cmd, buffer, 256, DMA_TO_DEVICE);
  	kfree(buffer);
  	return result;
  }

  static int ch_gstatus(scsi_changer *ch, int type, unsigned char __user *dest)

  {
  	int retval = 0;
  	u_char data[16];
  	unsigned int i;

  	mutex_lock(&ch->lock);

  	for (i = 0; i < ch->counts[type]; i++) {
  		if (0 != ch_read_element_status
  		    (ch, ch->firsts[type]+i,data)) {
  			retval = -EIO;
  			break;
  		}
  		put_user(data[2], dest+i);
  		if (data[2] & CESTATUS_EXCEPT)

  			VPRINTK(KERN_INFO, "element 0x%x: asc=0x%x, ascq=0x%x
  ",

  				ch->firsts[type]+i,
  				(int)data[4],(int)data[5]);
  		retval = ch_read_element_status
  			(ch, ch->firsts[type]+i,data);
  		if (0 != retval)
  			break;
  	}

  	mutex_unlock(&ch->lock);

  	return retval;
  }
  
  /* ------------------------------------------------------------------------ */
  
  static int
  ch_release(struct inode *inode, struct file *file)
  {
  	scsi_changer *ch = file->private_data;
  
  	scsi_device_put(ch->device);
  	file->private_data = NULL;
  	return 0;
  }
  
  static int
  ch_open(struct inode *inode, struct file *file)
  {

  	scsi_changer *ch;

  	int minor = iminor(inode);

  	lock_kernel();

  	spin_lock(&ch_index_lock);
  	ch = idr_find(&ch_index_idr, minor);

  	if (NULL == ch || scsi_device_get(ch->device)) {

  		spin_unlock(&ch_index_lock);

  		unlock_kernel();

  		return -ENXIO;
  	}

  	spin_unlock(&ch_index_lock);

  
  	file->private_data = ch;

  	unlock_kernel();

  	return 0;
  }
  
  static int
  ch_checkrange(scsi_changer *ch, unsigned int type, unsigned int unit)
  {
  	if (type >= CH_TYPES  ||  unit >= ch->counts[type])
  		return -1;
  	return 0;
  }

  static long ch_ioctl(struct file *file,

  		    unsigned int cmd, unsigned long arg)
  {
  	scsi_changer *ch = file->private_data;
  	int retval;

  	void __user *argp = (void __user *)arg;

  	switch (cmd) {
  	case CHIOGPARAMS:
  	{
  		struct changer_params params;

  		params.cp_curpicker = 0;
  		params.cp_npickers  = ch->counts[CHET_MT];
  		params.cp_nslots    = ch->counts[CHET_ST];
  		params.cp_nportals  = ch->counts[CHET_IE];
  		params.cp_ndrives   = ch->counts[CHET_DT];

  		if (copy_to_user(argp, &params, sizeof(params)))

  			return -EFAULT;
  		return 0;
  	}
  	case CHIOGVPARAMS:
  	{
  		struct changer_vendor_params vparams;
  
  		memset(&vparams,0,sizeof(vparams));
  		if (ch->counts[CHET_V1]) {
  			vparams.cvp_n1  = ch->counts[CHET_V1];
  			strncpy(vparams.cvp_label1,vendor_labels[0],16);
  		}
  		if (ch->counts[CHET_V2]) {
  			vparams.cvp_n2  = ch->counts[CHET_V2];
  			strncpy(vparams.cvp_label2,vendor_labels[1],16);
  		}
  		if (ch->counts[CHET_V3]) {
  			vparams.cvp_n3  = ch->counts[CHET_V3];
  			strncpy(vparams.cvp_label3,vendor_labels[2],16);
  		}
  		if (ch->counts[CHET_V4]) {
  			vparams.cvp_n4  = ch->counts[CHET_V4];
  			strncpy(vparams.cvp_label4,vendor_labels[3],16);
  		}

  		if (copy_to_user(argp, &vparams, sizeof(vparams)))

  			return -EFAULT;
  		return 0;
  	}

  	case CHIOPOSITION:
  	{
  		struct changer_position pos;

  		if (copy_from_user(&pos, argp, sizeof (pos)))

  			return -EFAULT;
  
  		if (0 != ch_checkrange(ch, pos.cp_type, pos.cp_unit)) {

  			DPRINTK("CHIOPOSITION: invalid parameter
  ");

  			return -EBADSLT;
  		}

  		mutex_lock(&ch->lock);

  		retval = ch_position(ch,0,
  				     ch->firsts[pos.cp_type] + pos.cp_unit,
  				     pos.cp_flags & CP_INVERT);

  		mutex_unlock(&ch->lock);

  		return retval;
  	}

  	case CHIOMOVE:
  	{
  		struct changer_move mv;

  		if (copy_from_user(&mv, argp, sizeof (mv)))

  			return -EFAULT;
  
  		if (0 != ch_checkrange(ch, mv.cm_fromtype, mv.cm_fromunit) ||
  		    0 != ch_checkrange(ch, mv.cm_totype,   mv.cm_tounit  )) {

  			DPRINTK("CHIOMOVE: invalid parameter
  ");

  			return -EBADSLT;
  		}

  		mutex_lock(&ch->lock);

  		retval = ch_move(ch,0,
  				 ch->firsts[mv.cm_fromtype] + mv.cm_fromunit,
  				 ch->firsts[mv.cm_totype]   + mv.cm_tounit,
  				 mv.cm_flags & CM_INVERT);

  		mutex_unlock(&ch->lock);

  		return retval;
  	}
  
  	case CHIOEXCHANGE:
  	{
  		struct changer_exchange mv;

  		if (copy_from_user(&mv, argp, sizeof (mv)))

  			return -EFAULT;
  
  		if (0 != ch_checkrange(ch, mv.ce_srctype,  mv.ce_srcunit ) ||
  		    0 != ch_checkrange(ch, mv.ce_fdsttype, mv.ce_fdstunit) ||
  		    0 != ch_checkrange(ch, mv.ce_sdsttype, mv.ce_sdstunit)) {

  			DPRINTK("CHIOEXCHANGE: invalid parameter
  ");

  			return -EBADSLT;
  		}

  		mutex_lock(&ch->lock);

  		retval = ch_exchange
  			(ch,0,
  			 ch->firsts[mv.ce_srctype]  + mv.ce_srcunit,
  			 ch->firsts[mv.ce_fdsttype] + mv.ce_fdstunit,
  			 ch->firsts[mv.ce_sdsttype] + mv.ce_sdstunit,
  			 mv.ce_flags & CE_INVERT1, mv.ce_flags & CE_INVERT2);

  		mutex_unlock(&ch->lock);

  		return retval;
  	}
  
  	case CHIOGSTATUS:
  	{
  		struct changer_element_status ces;

  		if (copy_from_user(&ces, argp, sizeof (ces)))

  			return -EFAULT;
  		if (ces.ces_type < 0 || ces.ces_type >= CH_TYPES)
  			return -EINVAL;
  
  		return ch_gstatus(ch, ces.ces_type, ces.ces_data);
  	}
  
  	case CHIOGELEM:
  	{
  		struct changer_get_element cge;

  		u_char ch_cmd[12];
  		u_char *buffer;

  		unsigned int elem;
  		int     result,i;

  		if (copy_from_user(&cge, argp, sizeof (cge)))

  			return -EFAULT;
  
  		if (0 != ch_checkrange(ch, cge.cge_type, cge.cge_unit))
  			return -EINVAL;
  		elem = ch->firsts[cge.cge_type] + cge.cge_unit;

  		buffer = kmalloc(512, GFP_KERNEL | GFP_DMA);
  		if (!buffer)
  			return -ENOMEM;

  		mutex_lock(&ch->lock);

  	voltag_retry:

  		memset(ch_cmd, 0, sizeof(ch_cmd));
  		ch_cmd[0] = READ_ELEMENT_STATUS;
  		ch_cmd[1] = (ch->device->lun << 5) |

  			(ch->voltags ? 0x10 : 0) |
  			ch_elem_to_typecode(ch,elem);

  		ch_cmd[2] = (elem >> 8) & 0xff;
  		ch_cmd[3] = elem        & 0xff;
  		ch_cmd[5] = 1;
  		ch_cmd[9] = 255;

  		result = ch_do_scsi(ch, ch_cmd, buffer, 256, DMA_FROM_DEVICE);
  		if (!result) {

  			cge.cge_status = buffer[18];
  			cge.cge_flags = 0;
  			if (buffer[18] & CESTATUS_EXCEPT) {
  				cge.cge_errno = EIO;
  			}
  			if (buffer[25] & 0x80) {
  				cge.cge_flags |= CGE_SRC;
  				if (buffer[25] & 0x40)
  					cge.cge_flags |= CGE_INVERT;
  				elem = (buffer[26]<<8) | buffer[27];
  				for (i = 0; i < 4; i++) {
  					if (elem >= ch->firsts[i] &&
  					    elem <  ch->firsts[i] + ch->counts[i]) {
  						cge.cge_srctype = i;
  						cge.cge_srcunit = elem-ch->firsts[i];
  					}
  				}
  			}
  			if ((buffer[22] & 0x30) == 0x30) {
  				cge.cge_flags |= CGE_IDLUN;
  				cge.cge_id  = buffer[23];
  				cge.cge_lun = buffer[22] & 7;
  			}
  			if (buffer[9] & 0x80) {
  				cge.cge_flags |= CGE_PVOLTAG;
  				memcpy(cge.cge_pvoltag,buffer+28,36);
  			}
  			if (buffer[9] & 0x40) {
  				cge.cge_flags |= CGE_AVOLTAG;
  				memcpy(cge.cge_avoltag,buffer+64,36);
  			}
  		} else if (ch->voltags) {
  			ch->voltags = 0;

  			VPRINTK(KERN_INFO, "device has no volume tag support
  ");

  			goto voltag_retry;
  		}
  		kfree(buffer);

  		mutex_unlock(&ch->lock);

  		if (copy_to_user(argp, &cge, sizeof (cge)))

  			return -EFAULT;
  		return result;
  	}
  
  	case CHIOINITELEM:
  	{

  		mutex_lock(&ch->lock);

  		retval = ch_init_elem(ch);

  		mutex_unlock(&ch->lock);

  		return retval;
  	}

  	case CHIOSVOLTAG:
  	{
  		struct changer_set_voltag csv;
  		int elem;

  		if (copy_from_user(&csv, argp, sizeof(csv)))

  			return -EFAULT;
  
  		if (0 != ch_checkrange(ch, csv.csv_type, csv.csv_unit)) {

  			DPRINTK("CHIOSVOLTAG: invalid parameter
  ");

  			return -EBADSLT;
  		}
  		elem = ch->firsts[csv.csv_type] + csv.csv_unit;

  		mutex_lock(&ch->lock);

  		retval = ch_set_voltag(ch, elem,
  				       csv.csv_flags & CSV_AVOLTAG,
  				       csv.csv_flags & CSV_CLEARTAG,
  				       csv.csv_voltag);

  		mutex_unlock(&ch->lock);

  		return retval;
  	}
  
  	default:

  		return scsi_ioctl(ch->device, cmd, argp);

  
  	}
  }
  
  #ifdef CONFIG_COMPAT
  
  struct changer_element_status32 {
  	int		ces_type;
  	compat_uptr_t	ces_data;
  };
  #define CHIOGSTATUS32  _IOW('c', 8,struct changer_element_status32)
  
  static long ch_ioctl_compat(struct file * file,
  			    unsigned int cmd, unsigned long arg)
  {
  	scsi_changer *ch = file->private_data;

  	switch (cmd) {
  	case CHIOGPARAMS:
  	case CHIOGVPARAMS:
  	case CHIOPOSITION:
  	case CHIOMOVE:
  	case CHIOEXCHANGE:
  	case CHIOGELEM:
  	case CHIOINITELEM:
  	case CHIOSVOLTAG:
  		/* compatible */

  		return ch_ioctl(file, cmd, arg);

  	case CHIOGSTATUS32:
  	{
  		struct changer_element_status32 ces32;

  		unsigned char __user *data;

  		if (copy_from_user(&ces32, (void __user *)arg, sizeof (ces32)))

  			return -EFAULT;
  		if (ces32.ces_type < 0 || ces32.ces_type >= CH_TYPES)
  			return -EINVAL;
  
  		data = compat_ptr(ces32.ces_data);
  		return ch_gstatus(ch, ces32.ces_type, data);
  	}
  	default:
  		// return scsi_ioctl_compat(ch->device, cmd, (void*)arg);
  		return -ENOIOCTLCMD;
  
  	}
  }
  #endif
  
  /* ------------------------------------------------------------------------ */
  
  static int ch_probe(struct device *dev)
  {
  	struct scsi_device *sd = to_scsi_device(dev);

  	struct device *class_dev;

  	int minor, ret = -ENOMEM;

  	scsi_changer *ch;

  	if (sd->type != TYPE_MEDIUM_CHANGER)
  		return -ENODEV;

  	ch = kzalloc(sizeof(*ch), GFP_KERNEL);

  	if (NULL == ch)
  		return -ENOMEM;

  	if (!idr_pre_get(&ch_index_idr, GFP_KERNEL))
  		goto free_ch;
  
  	spin_lock(&ch_index_lock);
  	ret = idr_get_new(&ch_index_idr, ch, &minor);
  	spin_unlock(&ch_index_lock);
  
  	if (ret)
  		goto free_ch;
  
  	if (minor > CH_MAX_DEVS) {
  		ret = -ENODEV;
  		goto remove_idr;
  	}
  
  	ch->minor = minor;

  	sprintf(ch->name,"ch%d",ch->minor);

  	class_dev = device_create(ch_sysfs_class, dev,
  				  MKDEV(SCSI_CHANGER_MAJOR, ch->minor), ch,
  				  "s%s", ch->name);

  	if (IS_ERR(class_dev)) {

  		printk(KERN_WARNING "ch%d: device_create failed
  ",

  		       ch->minor);

  		ret = PTR_ERR(class_dev);
  		goto remove_idr;

  	}

  	mutex_init(&ch->lock);

  	ch->device = sd;
  	ch_readconfig(ch);
  	if (init)
  		ch_init_elem(ch);

  	dev_set_drvdata(dev, ch);

  	sdev_printk(KERN_INFO, sd, "Attached scsi changer %s
  ", ch->name);

  	return 0;

  remove_idr:
  	idr_remove(&ch_index_idr, minor);
  free_ch:
  	kfree(ch);
  	return ret;

  }
  
  static int ch_remove(struct device *dev)
  {

  	scsi_changer *ch = dev_get_drvdata(dev);

  	spin_lock(&ch_index_lock);
  	idr_remove(&ch_index_idr, ch->minor);
  	spin_unlock(&ch_index_lock);

  	device_destroy(ch_sysfs_class, MKDEV(SCSI_CHANGER_MAJOR,ch->minor));

  	kfree(ch->dt);
  	kfree(ch);

  	return 0;
  }

  static struct scsi_driver ch_template = {
  	.owner     	= THIS_MODULE,
  	.gendrv     	= {
  		.name	= "ch",
  		.probe  = ch_probe,
  		.remove = ch_remove,
  	},
  };
  
  static const struct file_operations changer_fops = {
  	.owner		= THIS_MODULE,
  	.open		= ch_open,
  	.release	= ch_release,
  	.unlocked_ioctl	= ch_ioctl,
  #ifdef CONFIG_COMPAT
  	.compat_ioctl	= ch_ioctl_compat,
  #endif
  };

  static int __init init_ch_module(void)
  {
  	int rc;

  	printk(KERN_INFO "SCSI Media Changer driver v" VERSION " 
  ");

          ch_sysfs_class = class_create(THIS_MODULE, "scsi_changer");

          if (IS_ERR(ch_sysfs_class)) {
  		rc = PTR_ERR(ch_sysfs_class);
  		return rc;
          }
  	rc = register_chrdev(SCSI_CHANGER_MAJOR,"ch",&changer_fops);
  	if (rc < 0) {
  		printk("Unable to get major %d for SCSI-Changer
  ",
  		       SCSI_CHANGER_MAJOR);
  		goto fail1;
  	}
  	rc = scsi_register_driver(&ch_template.gendrv);
  	if (rc < 0)
  		goto fail2;
  	return 0;
  
   fail2:
  	unregister_chrdev(SCSI_CHANGER_MAJOR, "ch");
   fail1:

  	class_destroy(ch_sysfs_class);

  	return rc;
  }

  static void __exit exit_ch_module(void)

  {
  	scsi_unregister_driver(&ch_template.gendrv);
  	unregister_chrdev(SCSI_CHANGER_MAJOR, "ch");

  	class_destroy(ch_sysfs_class);

  	idr_destroy(&ch_index_idr);

  }
  
  module_init(init_ch_module);
  module_exit(exit_ch_module);
  
  /*
   * Local variables:
   * c-basic-offset: 8
   * End:
   */