xref: /linux/drivers/scsi/ch.c (revision 987b741c52c7c6c68d46fbaeb95b8d1087f10b7f)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * SCSI Media Changer device driver for Linux 2.6
4  *
5  *     (c) 1996-2003 Gerd Knorr <kraxel@bytesex.org>
6  *
7  */
8 
9 #define VERSION "0.25"
10 
11 #include <linux/module.h>
12 #include <linux/init.h>
13 #include <linux/fs.h>
14 #include <linux/kernel.h>
15 #include <linux/mm.h>
16 #include <linux/major.h>
17 #include <linux/string.h>
18 #include <linux/errno.h>
19 #include <linux/interrupt.h>
20 #include <linux/blkdev.h>
21 #include <linux/completion.h>
22 #include <linux/compat.h>
23 #include <linux/chio.h>			/* here are all the ioctls */
24 #include <linux/mutex.h>
25 #include <linux/idr.h>
26 #include <linux/slab.h>
27 
28 #include <scsi/scsi.h>
29 #include <scsi/scsi_cmnd.h>
30 #include <scsi/scsi_driver.h>
31 #include <scsi/scsi_ioctl.h>
32 #include <scsi/scsi_host.h>
33 #include <scsi/scsi_device.h>
34 #include <scsi/scsi_eh.h>
35 #include <scsi/scsi_dbg.h>
36 
37 #define CH_DT_MAX       16
38 #define CH_TYPES        8
39 #define CH_MAX_DEVS     128
40 
41 MODULE_DESCRIPTION("device driver for scsi media changer devices");
42 MODULE_AUTHOR("Gerd Knorr <kraxel@bytesex.org>");
43 MODULE_LICENSE("GPL");
44 MODULE_ALIAS_CHARDEV_MAJOR(SCSI_CHANGER_MAJOR);
45 MODULE_ALIAS_SCSI_DEVICE(TYPE_MEDIUM_CHANGER);
46 
47 static int init = 1;
48 module_param(init, int, 0444);
49 MODULE_PARM_DESC(init, \
50     "initialize element status on driver load (default: on)");
51 
52 static int timeout_move = 300;
53 module_param(timeout_move, int, 0644);
54 MODULE_PARM_DESC(timeout_move,"timeout for move commands "
55 		 "(default: 300 seconds)");
56 
57 static int timeout_init = 3600;
58 module_param(timeout_init, int, 0644);
59 MODULE_PARM_DESC(timeout_init,"timeout for INITIALIZE ELEMENT STATUS "
60 		 "(default: 3600 seconds)");
61 
62 static int verbose = 1;
63 module_param(verbose, int, 0644);
64 MODULE_PARM_DESC(verbose,"be verbose (default: on)");
65 
66 static int debug = 0;
67 module_param(debug, int, 0644);
68 MODULE_PARM_DESC(debug,"enable/disable debug messages, also prints more "
69 		 "detailed sense codes on scsi errors (default: off)");
70 
71 static int dt_id[CH_DT_MAX] = { [ 0 ... (CH_DT_MAX-1) ] = -1 };
72 static int dt_lun[CH_DT_MAX];
73 module_param_array(dt_id,  int, NULL, 0444);
74 module_param_array(dt_lun, int, NULL, 0444);
75 
76 /* tell the driver about vendor-specific slots */
77 static int vendor_firsts[CH_TYPES-4];
78 static int vendor_counts[CH_TYPES-4];
79 module_param_array(vendor_firsts, int, NULL, 0444);
80 module_param_array(vendor_counts, int, NULL, 0444);
81 
82 static const char * vendor_labels[CH_TYPES-4] = {
83 	"v0", "v1", "v2", "v3"
84 };
85 // module_param_string_array(vendor_labels, NULL, 0444);
86 
87 #define ch_printk(prefix, ch, fmt, a...) \
88 	sdev_prefix_printk(prefix, (ch)->device, (ch)->name, fmt, ##a)
89 
90 #define DPRINTK(fmt, arg...)						\
91 do {									\
92 	if (debug)							\
93 		ch_printk(KERN_DEBUG, ch, fmt, ##arg);			\
94 } while (0)
95 #define VPRINTK(level, fmt, arg...)					\
96 do {									\
97 	if (verbose)							\
98 		ch_printk(level, ch, fmt, ##arg);			\
99 } while (0)
100 
101 /* ------------------------------------------------------------------- */
102 
103 #define MAX_RETRIES   1
104 
105 static struct class * ch_sysfs_class;
106 
107 typedef struct {
108 	struct kref         ref;
109 	struct list_head    list;
110 	int                 minor;
111 	char                name[8];
112 	struct scsi_device  *device;
113 	struct scsi_device  **dt;        /* ptrs to data transfer elements */
114 	u_int               firsts[CH_TYPES];
115 	u_int               counts[CH_TYPES];
116 	u_int               unit_attention;
117 	u_int		    voltags;
118 	struct mutex	    lock;
119 } scsi_changer;
120 
121 static DEFINE_IDR(ch_index_idr);
122 static DEFINE_SPINLOCK(ch_index_lock);
123 
124 static const struct {
125 	unsigned char  sense;
126 	unsigned char  asc;
127 	unsigned char  ascq;
128 	int	       errno;
129 } ch_err[] = {
130 /* Just filled in what looks right. Hav'nt checked any standard paper for
131    these errno assignments, so they may be wrong... */
132 	{
133 		.sense  = ILLEGAL_REQUEST,
134 		.asc    = 0x21,
135 		.ascq   = 0x01,
136 		.errno  = EBADSLT, /* Invalid element address */
137 	},{
138 		.sense  = ILLEGAL_REQUEST,
139 		.asc    = 0x28,
140 		.ascq   = 0x01,
141 		.errno  = EBADE,   /* Import or export element accessed */
142 	},{
143 		.sense  = ILLEGAL_REQUEST,
144 		.asc    = 0x3B,
145 		.ascq   = 0x0D,
146 		.errno  = EXFULL,  /* Medium destination element full */
147 	},{
148 		.sense  = ILLEGAL_REQUEST,
149 		.asc    = 0x3B,
150 		.ascq   = 0x0E,
151 		.errno  = EBADE,   /* Medium source element empty */
152 	},{
153 		.sense  = ILLEGAL_REQUEST,
154 		.asc    = 0x20,
155 		.ascq   = 0x00,
156 		.errno  = EBADRQC, /* Invalid command operation code */
157 	},{
158 	        /* end of list */
159 	}
160 };
161 
162 /* ------------------------------------------------------------------- */
163 
164 static int ch_find_errno(struct scsi_sense_hdr *sshdr)
165 {
166 	int i,errno = 0;
167 
168 	/* Check to see if additional sense information is available */
169 	if (scsi_sense_valid(sshdr) &&
170 	    sshdr->asc != 0) {
171 		for (i = 0; ch_err[i].errno != 0; i++) {
172 			if (ch_err[i].sense == sshdr->sense_key &&
173 			    ch_err[i].asc   == sshdr->asc &&
174 			    ch_err[i].ascq  == sshdr->ascq) {
175 				errno = -ch_err[i].errno;
176 				break;
177 			}
178 		}
179 	}
180 	if (errno == 0)
181 		errno = -EIO;
182 	return errno;
183 }
184 
185 static int
186 ch_do_scsi(scsi_changer *ch, unsigned char *cmd, int cmd_len,
187 	   void *buffer, unsigned buflength,
188 	   enum dma_data_direction direction)
189 {
190 	int errno, retries = 0, timeout, result;
191 	struct scsi_sense_hdr sshdr;
192 
193 	timeout = (cmd[0] == INITIALIZE_ELEMENT_STATUS)
194 		? timeout_init : timeout_move;
195 
196  retry:
197 	errno = 0;
198 	result = scsi_execute_req(ch->device, cmd, direction, buffer,
199 				  buflength, &sshdr, timeout * HZ,
200 				  MAX_RETRIES, NULL);
201 
202 	if (driver_byte(result) == DRIVER_SENSE) {
203 		if (debug)
204 			scsi_print_sense_hdr(ch->device, ch->name, &sshdr);
205 		errno = ch_find_errno(&sshdr);
206 
207 		switch(sshdr.sense_key) {
208 		case UNIT_ATTENTION:
209 			ch->unit_attention = 1;
210 			if (retries++ < 3)
211 				goto retry;
212 			break;
213 		}
214 	}
215 	return errno;
216 }
217 
218 /* ------------------------------------------------------------------------ */
219 
220 static int
221 ch_elem_to_typecode(scsi_changer *ch, u_int elem)
222 {
223 	int i;
224 
225 	for (i = 0; i < CH_TYPES; i++) {
226 		if (elem >= ch->firsts[i]  &&
227 		    elem <  ch->firsts[i] +
228 	            ch->counts[i])
229 			return i+1;
230 	}
231 	return 0;
232 }
233 
234 static int
235 ch_read_element_status(scsi_changer *ch, u_int elem, char *data)
236 {
237 	u_char  cmd[12];
238 	u_char  *buffer;
239 	int     result;
240 
241 	buffer = kmalloc(512, GFP_KERNEL | GFP_DMA);
242 	if(!buffer)
243 		return -ENOMEM;
244 
245  retry:
246 	memset(cmd,0,sizeof(cmd));
247 	cmd[0] = READ_ELEMENT_STATUS;
248 	cmd[1] = ((ch->device->lun & 0x7) << 5) |
249 		(ch->voltags ? 0x10 : 0) |
250 		ch_elem_to_typecode(ch,elem);
251 	cmd[2] = (elem >> 8) & 0xff;
252 	cmd[3] = elem        & 0xff;
253 	cmd[5] = 1;
254 	cmd[9] = 255;
255 	if (0 == (result = ch_do_scsi(ch, cmd, 12,
256 				      buffer, 256, DMA_FROM_DEVICE))) {
257 		if (((buffer[16] << 8) | buffer[17]) != elem) {
258 			DPRINTK("asked for element 0x%02x, got 0x%02x\n",
259 				elem,(buffer[16] << 8) | buffer[17]);
260 			kfree(buffer);
261 			return -EIO;
262 		}
263 		memcpy(data,buffer+16,16);
264 	} else {
265 		if (ch->voltags) {
266 			ch->voltags = 0;
267 			VPRINTK(KERN_INFO, "device has no volume tag support\n");
268 			goto retry;
269 		}
270 		DPRINTK("READ ELEMENT STATUS for element 0x%x failed\n",elem);
271 	}
272 	kfree(buffer);
273 	return result;
274 }
275 
276 static int
277 ch_init_elem(scsi_changer *ch)
278 {
279 	int err;
280 	u_char cmd[6];
281 
282 	VPRINTK(KERN_INFO, "INITIALIZE ELEMENT STATUS, may take some time ...\n");
283 	memset(cmd,0,sizeof(cmd));
284 	cmd[0] = INITIALIZE_ELEMENT_STATUS;
285 	cmd[1] = (ch->device->lun & 0x7) << 5;
286 	err = ch_do_scsi(ch, cmd, 6, NULL, 0, DMA_NONE);
287 	VPRINTK(KERN_INFO, "... finished\n");
288 	return err;
289 }
290 
291 static int
292 ch_readconfig(scsi_changer *ch)
293 {
294 	u_char  cmd[10], data[16];
295 	u_char  *buffer;
296 	int     result,id,lun,i;
297 	u_int   elem;
298 
299 	buffer = kzalloc(512, GFP_KERNEL | GFP_DMA);
300 	if (!buffer)
301 		return -ENOMEM;
302 
303 	memset(cmd,0,sizeof(cmd));
304 	cmd[0] = MODE_SENSE;
305 	cmd[1] = (ch->device->lun & 0x7) << 5;
306 	cmd[2] = 0x1d;
307 	cmd[4] = 255;
308 	result = ch_do_scsi(ch, cmd, 10, buffer, 255, DMA_FROM_DEVICE);
309 	if (0 != result) {
310 		cmd[1] |= (1<<3);
311 		result  = ch_do_scsi(ch, cmd, 10, buffer, 255, DMA_FROM_DEVICE);
312 	}
313 	if (0 == result) {
314 		ch->firsts[CHET_MT] =
315 			(buffer[buffer[3]+ 6] << 8) | buffer[buffer[3]+ 7];
316 		ch->counts[CHET_MT] =
317 			(buffer[buffer[3]+ 8] << 8) | buffer[buffer[3]+ 9];
318 		ch->firsts[CHET_ST] =
319 			(buffer[buffer[3]+10] << 8) | buffer[buffer[3]+11];
320 		ch->counts[CHET_ST] =
321 			(buffer[buffer[3]+12] << 8) | buffer[buffer[3]+13];
322 		ch->firsts[CHET_IE] =
323 			(buffer[buffer[3]+14] << 8) | buffer[buffer[3]+15];
324 		ch->counts[CHET_IE] =
325 			(buffer[buffer[3]+16] << 8) | buffer[buffer[3]+17];
326 		ch->firsts[CHET_DT] =
327 			(buffer[buffer[3]+18] << 8) | buffer[buffer[3]+19];
328 		ch->counts[CHET_DT] =
329 			(buffer[buffer[3]+20] << 8) | buffer[buffer[3]+21];
330 		VPRINTK(KERN_INFO, "type #1 (mt): 0x%x+%d [medium transport]\n",
331 			ch->firsts[CHET_MT],
332 			ch->counts[CHET_MT]);
333 		VPRINTK(KERN_INFO, "type #2 (st): 0x%x+%d [storage]\n",
334 			ch->firsts[CHET_ST],
335 			ch->counts[CHET_ST]);
336 		VPRINTK(KERN_INFO, "type #3 (ie): 0x%x+%d [import/export]\n",
337 			ch->firsts[CHET_IE],
338 			ch->counts[CHET_IE]);
339 		VPRINTK(KERN_INFO, "type #4 (dt): 0x%x+%d [data transfer]\n",
340 			ch->firsts[CHET_DT],
341 			ch->counts[CHET_DT]);
342 	} else {
343 		VPRINTK(KERN_INFO, "reading element address assignment page failed!\n");
344 	}
345 
346 	/* vendor specific element types */
347 	for (i = 0; i < 4; i++) {
348 		if (0 == vendor_counts[i])
349 			continue;
350 		if (NULL == vendor_labels[i])
351 			continue;
352 		ch->firsts[CHET_V1+i] = vendor_firsts[i];
353 		ch->counts[CHET_V1+i] = vendor_counts[i];
354 		VPRINTK(KERN_INFO, "type #%d (v%d): 0x%x+%d [%s, vendor specific]\n",
355 			i+5,i+1,vendor_firsts[i],vendor_counts[i],
356 			vendor_labels[i]);
357 	}
358 
359 	/* look up the devices of the data transfer elements */
360 	ch->dt = kcalloc(ch->counts[CHET_DT], sizeof(*ch->dt),
361 			 GFP_KERNEL);
362 
363 	if (!ch->dt) {
364 		kfree(buffer);
365 		return -ENOMEM;
366 	}
367 
368 	for (elem = 0; elem < ch->counts[CHET_DT]; elem++) {
369 		id  = -1;
370 		lun = 0;
371 		if (elem < CH_DT_MAX  &&  -1 != dt_id[elem]) {
372 			id  = dt_id[elem];
373 			lun = dt_lun[elem];
374 			VPRINTK(KERN_INFO, "dt 0x%x: [insmod option] ",
375 				elem+ch->firsts[CHET_DT]);
376 		} else if (0 != ch_read_element_status
377 			   (ch,elem+ch->firsts[CHET_DT],data)) {
378 			VPRINTK(KERN_INFO, "dt 0x%x: READ ELEMENT STATUS failed\n",
379 				elem+ch->firsts[CHET_DT]);
380 		} else {
381 			VPRINTK(KERN_INFO, "dt 0x%x: ",elem+ch->firsts[CHET_DT]);
382 			if (data[6] & 0x80) {
383 				VPRINTK(KERN_CONT, "not this SCSI bus\n");
384 				ch->dt[elem] = NULL;
385 			} else if (0 == (data[6] & 0x30)) {
386 				VPRINTK(KERN_CONT, "ID/LUN unknown\n");
387 				ch->dt[elem] = NULL;
388 			} else {
389 				id  = ch->device->id;
390 				lun = 0;
391 				if (data[6] & 0x20) id  = data[7];
392 				if (data[6] & 0x10) lun = data[6] & 7;
393 			}
394 		}
395 		if (-1 != id) {
396 			VPRINTK(KERN_CONT, "ID %i, LUN %i, ",id,lun);
397 			ch->dt[elem] =
398 				scsi_device_lookup(ch->device->host,
399 						   ch->device->channel,
400 						   id,lun);
401 			if (!ch->dt[elem]) {
402 				/* should not happen */
403 				VPRINTK(KERN_CONT, "Huh? device not found!\n");
404 			} else {
405 				VPRINTK(KERN_CONT, "name: %8.8s %16.16s %4.4s\n",
406 					ch->dt[elem]->vendor,
407 					ch->dt[elem]->model,
408 					ch->dt[elem]->rev);
409 			}
410 		}
411 	}
412 	ch->voltags = 1;
413 	kfree(buffer);
414 
415 	return 0;
416 }
417 
418 /* ------------------------------------------------------------------------ */
419 
420 static int
421 ch_position(scsi_changer *ch, u_int trans, u_int elem, int rotate)
422 {
423 	u_char  cmd[10];
424 
425 	DPRINTK("position: 0x%x\n",elem);
426 	if (0 == trans)
427 		trans = ch->firsts[CHET_MT];
428 	memset(cmd,0,sizeof(cmd));
429 	cmd[0]  = POSITION_TO_ELEMENT;
430 	cmd[1]  = (ch->device->lun & 0x7) << 5;
431 	cmd[2]  = (trans >> 8) & 0xff;
432 	cmd[3]  =  trans       & 0xff;
433 	cmd[4]  = (elem  >> 8) & 0xff;
434 	cmd[5]  =  elem        & 0xff;
435 	cmd[8]  = rotate ? 1 : 0;
436 	return ch_do_scsi(ch, cmd, 10, NULL, 0, DMA_NONE);
437 }
438 
439 static int
440 ch_move(scsi_changer *ch, u_int trans, u_int src, u_int dest, int rotate)
441 {
442 	u_char  cmd[12];
443 
444 	DPRINTK("move: 0x%x => 0x%x\n",src,dest);
445 	if (0 == trans)
446 		trans = ch->firsts[CHET_MT];
447 	memset(cmd,0,sizeof(cmd));
448 	cmd[0]  = MOVE_MEDIUM;
449 	cmd[1]  = (ch->device->lun & 0x7) << 5;
450 	cmd[2]  = (trans >> 8) & 0xff;
451 	cmd[3]  =  trans       & 0xff;
452 	cmd[4]  = (src   >> 8) & 0xff;
453 	cmd[5]  =  src         & 0xff;
454 	cmd[6]  = (dest  >> 8) & 0xff;
455 	cmd[7]  =  dest        & 0xff;
456 	cmd[10] = rotate ? 1 : 0;
457 	return ch_do_scsi(ch, cmd, 12, NULL,0, DMA_NONE);
458 }
459 
460 static int
461 ch_exchange(scsi_changer *ch, u_int trans, u_int src,
462 	    u_int dest1, u_int dest2, int rotate1, int rotate2)
463 {
464 	u_char  cmd[12];
465 
466 	DPRINTK("exchange: 0x%x => 0x%x => 0x%x\n",
467 		src,dest1,dest2);
468 	if (0 == trans)
469 		trans = ch->firsts[CHET_MT];
470 	memset(cmd,0,sizeof(cmd));
471 	cmd[0]  = EXCHANGE_MEDIUM;
472 	cmd[1]  = (ch->device->lun & 0x7) << 5;
473 	cmd[2]  = (trans >> 8) & 0xff;
474 	cmd[3]  =  trans       & 0xff;
475 	cmd[4]  = (src   >> 8) & 0xff;
476 	cmd[5]  =  src         & 0xff;
477 	cmd[6]  = (dest1 >> 8) & 0xff;
478 	cmd[7]  =  dest1       & 0xff;
479 	cmd[8]  = (dest2 >> 8) & 0xff;
480 	cmd[9]  =  dest2       & 0xff;
481 	cmd[10] = (rotate1 ? 1 : 0) | (rotate2 ? 2 : 0);
482 
483 	return ch_do_scsi(ch, cmd, 12, NULL, 0, DMA_NONE);
484 }
485 
486 static void
487 ch_check_voltag(char *tag)
488 {
489 	int i;
490 
491 	for (i = 0; i < 32; i++) {
492 		/* restrict to ascii */
493 		if (tag[i] >= 0x7f || tag[i] < 0x20)
494 			tag[i] = ' ';
495 		/* don't allow search wildcards */
496 		if (tag[i] == '?' ||
497 		    tag[i] == '*')
498 			tag[i] = ' ';
499 	}
500 }
501 
502 static int
503 ch_set_voltag(scsi_changer *ch, u_int elem,
504 	      int alternate, int clear, u_char *tag)
505 {
506 	u_char  cmd[12];
507 	u_char  *buffer;
508 	int result;
509 
510 	buffer = kzalloc(512, GFP_KERNEL);
511 	if (!buffer)
512 		return -ENOMEM;
513 
514 	DPRINTK("%s %s voltag: 0x%x => \"%s\"\n",
515 		clear     ? "clear"     : "set",
516 		alternate ? "alternate" : "primary",
517 		elem, tag);
518 	memset(cmd,0,sizeof(cmd));
519 	cmd[0]  = SEND_VOLUME_TAG;
520 	cmd[1] = ((ch->device->lun & 0x7) << 5) |
521 		ch_elem_to_typecode(ch,elem);
522 	cmd[2] = (elem >> 8) & 0xff;
523 	cmd[3] = elem        & 0xff;
524 	cmd[5] = clear
525 		? (alternate ? 0x0d : 0x0c)
526 		: (alternate ? 0x0b : 0x0a);
527 
528 	cmd[9] = 255;
529 
530 	memcpy(buffer,tag,32);
531 	ch_check_voltag(buffer);
532 
533 	result = ch_do_scsi(ch, cmd, 12, buffer, 256, DMA_TO_DEVICE);
534 	kfree(buffer);
535 	return result;
536 }
537 
538 static int ch_gstatus(scsi_changer *ch, int type, unsigned char __user *dest)
539 {
540 	int retval = 0;
541 	u_char data[16];
542 	unsigned int i;
543 
544 	mutex_lock(&ch->lock);
545 	for (i = 0; i < ch->counts[type]; i++) {
546 		if (0 != ch_read_element_status
547 		    (ch, ch->firsts[type]+i,data)) {
548 			retval = -EIO;
549 			break;
550 		}
551 		put_user(data[2], dest+i);
552 		if (data[2] & CESTATUS_EXCEPT)
553 			VPRINTK(KERN_INFO, "element 0x%x: asc=0x%x, ascq=0x%x\n",
554 				ch->firsts[type]+i,
555 				(int)data[4],(int)data[5]);
556 		retval = ch_read_element_status
557 			(ch, ch->firsts[type]+i,data);
558 		if (0 != retval)
559 			break;
560 	}
561 	mutex_unlock(&ch->lock);
562 	return retval;
563 }
564 
565 /* ------------------------------------------------------------------------ */
566 
567 static void ch_destroy(struct kref *ref)
568 {
569 	scsi_changer *ch = container_of(ref, scsi_changer, ref);
570 
571 	ch->device = NULL;
572 	kfree(ch->dt);
573 	kfree(ch);
574 }
575 
576 static int
577 ch_release(struct inode *inode, struct file *file)
578 {
579 	scsi_changer *ch = file->private_data;
580 
581 	scsi_device_put(ch->device);
582 	file->private_data = NULL;
583 	kref_put(&ch->ref, ch_destroy);
584 	return 0;
585 }
586 
587 static int
588 ch_open(struct inode *inode, struct file *file)
589 {
590 	scsi_changer *ch;
591 	int minor = iminor(inode);
592 
593 	spin_lock(&ch_index_lock);
594 	ch = idr_find(&ch_index_idr, minor);
595 
596 	if (ch == NULL || !kref_get_unless_zero(&ch->ref)) {
597 		spin_unlock(&ch_index_lock);
598 		return -ENXIO;
599 	}
600 	spin_unlock(&ch_index_lock);
601 	if (scsi_device_get(ch->device)) {
602 		kref_put(&ch->ref, ch_destroy);
603 		return -ENXIO;
604 	}
605 	/* Synchronize with ch_probe() */
606 	mutex_lock(&ch->lock);
607 	file->private_data = ch;
608 	mutex_unlock(&ch->lock);
609 	return 0;
610 }
611 
612 static int
613 ch_checkrange(scsi_changer *ch, unsigned int type, unsigned int unit)
614 {
615 	if (type >= CH_TYPES  ||  unit >= ch->counts[type])
616 		return -1;
617 	return 0;
618 }
619 
620 static long ch_ioctl(struct file *file,
621 		    unsigned int cmd, unsigned long arg)
622 {
623 	scsi_changer *ch = file->private_data;
624 	int retval;
625 	void __user *argp = (void __user *)arg;
626 
627 	retval = scsi_ioctl_block_when_processing_errors(ch->device, cmd,
628 			file->f_flags & O_NDELAY);
629 	if (retval)
630 		return retval;
631 
632 	switch (cmd) {
633 	case CHIOGPARAMS:
634 	{
635 		struct changer_params params;
636 
637 		params.cp_curpicker = 0;
638 		params.cp_npickers  = ch->counts[CHET_MT];
639 		params.cp_nslots    = ch->counts[CHET_ST];
640 		params.cp_nportals  = ch->counts[CHET_IE];
641 		params.cp_ndrives   = ch->counts[CHET_DT];
642 
643 		if (copy_to_user(argp, &params, sizeof(params)))
644 			return -EFAULT;
645 		return 0;
646 	}
647 	case CHIOGVPARAMS:
648 	{
649 		struct changer_vendor_params vparams;
650 
651 		memset(&vparams,0,sizeof(vparams));
652 		if (ch->counts[CHET_V1]) {
653 			vparams.cvp_n1  = ch->counts[CHET_V1];
654 			strncpy(vparams.cvp_label1,vendor_labels[0],16);
655 		}
656 		if (ch->counts[CHET_V2]) {
657 			vparams.cvp_n2  = ch->counts[CHET_V2];
658 			strncpy(vparams.cvp_label2,vendor_labels[1],16);
659 		}
660 		if (ch->counts[CHET_V3]) {
661 			vparams.cvp_n3  = ch->counts[CHET_V3];
662 			strncpy(vparams.cvp_label3,vendor_labels[2],16);
663 		}
664 		if (ch->counts[CHET_V4]) {
665 			vparams.cvp_n4  = ch->counts[CHET_V4];
666 			strncpy(vparams.cvp_label4,vendor_labels[3],16);
667 		}
668 		if (copy_to_user(argp, &vparams, sizeof(vparams)))
669 			return -EFAULT;
670 		return 0;
671 	}
672 
673 	case CHIOPOSITION:
674 	{
675 		struct changer_position pos;
676 
677 		if (copy_from_user(&pos, argp, sizeof (pos)))
678 			return -EFAULT;
679 
680 		if (0 != ch_checkrange(ch, pos.cp_type, pos.cp_unit)) {
681 			DPRINTK("CHIOPOSITION: invalid parameter\n");
682 			return -EBADSLT;
683 		}
684 		mutex_lock(&ch->lock);
685 		retval = ch_position(ch,0,
686 				     ch->firsts[pos.cp_type] + pos.cp_unit,
687 				     pos.cp_flags & CP_INVERT);
688 		mutex_unlock(&ch->lock);
689 		return retval;
690 	}
691 
692 	case CHIOMOVE:
693 	{
694 		struct changer_move mv;
695 
696 		if (copy_from_user(&mv, argp, sizeof (mv)))
697 			return -EFAULT;
698 
699 		if (0 != ch_checkrange(ch, mv.cm_fromtype, mv.cm_fromunit) ||
700 		    0 != ch_checkrange(ch, mv.cm_totype,   mv.cm_tounit  )) {
701 			DPRINTK("CHIOMOVE: invalid parameter\n");
702 			return -EBADSLT;
703 		}
704 
705 		mutex_lock(&ch->lock);
706 		retval = ch_move(ch,0,
707 				 ch->firsts[mv.cm_fromtype] + mv.cm_fromunit,
708 				 ch->firsts[mv.cm_totype]   + mv.cm_tounit,
709 				 mv.cm_flags & CM_INVERT);
710 		mutex_unlock(&ch->lock);
711 		return retval;
712 	}
713 
714 	case CHIOEXCHANGE:
715 	{
716 		struct changer_exchange mv;
717 
718 		if (copy_from_user(&mv, argp, sizeof (mv)))
719 			return -EFAULT;
720 
721 		if (0 != ch_checkrange(ch, mv.ce_srctype,  mv.ce_srcunit ) ||
722 		    0 != ch_checkrange(ch, mv.ce_fdsttype, mv.ce_fdstunit) ||
723 		    0 != ch_checkrange(ch, mv.ce_sdsttype, mv.ce_sdstunit)) {
724 			DPRINTK("CHIOEXCHANGE: invalid parameter\n");
725 			return -EBADSLT;
726 		}
727 
728 		mutex_lock(&ch->lock);
729 		retval = ch_exchange
730 			(ch,0,
731 			 ch->firsts[mv.ce_srctype]  + mv.ce_srcunit,
732 			 ch->firsts[mv.ce_fdsttype] + mv.ce_fdstunit,
733 			 ch->firsts[mv.ce_sdsttype] + mv.ce_sdstunit,
734 			 mv.ce_flags & CE_INVERT1, mv.ce_flags & CE_INVERT2);
735 		mutex_unlock(&ch->lock);
736 		return retval;
737 	}
738 
739 	case CHIOGSTATUS:
740 	{
741 		struct changer_element_status ces;
742 
743 		if (copy_from_user(&ces, argp, sizeof (ces)))
744 			return -EFAULT;
745 		if (ces.ces_type < 0 || ces.ces_type >= CH_TYPES)
746 			return -EINVAL;
747 
748 		return ch_gstatus(ch, ces.ces_type, ces.ces_data);
749 	}
750 
751 	case CHIOGELEM:
752 	{
753 		struct changer_get_element cge;
754 		u_char ch_cmd[12];
755 		u_char *buffer;
756 		unsigned int elem;
757 		int     result,i;
758 
759 		if (copy_from_user(&cge, argp, sizeof (cge)))
760 			return -EFAULT;
761 
762 		if (0 != ch_checkrange(ch, cge.cge_type, cge.cge_unit))
763 			return -EINVAL;
764 		elem = ch->firsts[cge.cge_type] + cge.cge_unit;
765 
766 		buffer = kmalloc(512, GFP_KERNEL | GFP_DMA);
767 		if (!buffer)
768 			return -ENOMEM;
769 		mutex_lock(&ch->lock);
770 
771 	voltag_retry:
772 		memset(ch_cmd, 0, sizeof(ch_cmd));
773 		ch_cmd[0] = READ_ELEMENT_STATUS;
774 		ch_cmd[1] = ((ch->device->lun & 0x7) << 5) |
775 			(ch->voltags ? 0x10 : 0) |
776 			ch_elem_to_typecode(ch,elem);
777 		ch_cmd[2] = (elem >> 8) & 0xff;
778 		ch_cmd[3] = elem        & 0xff;
779 		ch_cmd[5] = 1;
780 		ch_cmd[9] = 255;
781 
782 		result = ch_do_scsi(ch, ch_cmd, 12,
783 				    buffer, 256, DMA_FROM_DEVICE);
784 		if (!result) {
785 			cge.cge_status = buffer[18];
786 			cge.cge_flags = 0;
787 			if (buffer[18] & CESTATUS_EXCEPT) {
788 				cge.cge_errno = EIO;
789 			}
790 			if (buffer[25] & 0x80) {
791 				cge.cge_flags |= CGE_SRC;
792 				if (buffer[25] & 0x40)
793 					cge.cge_flags |= CGE_INVERT;
794 				elem = (buffer[26]<<8) | buffer[27];
795 				for (i = 0; i < 4; i++) {
796 					if (elem >= ch->firsts[i] &&
797 					    elem <  ch->firsts[i] + ch->counts[i]) {
798 						cge.cge_srctype = i;
799 						cge.cge_srcunit = elem-ch->firsts[i];
800 					}
801 				}
802 			}
803 			if ((buffer[22] & 0x30) == 0x30) {
804 				cge.cge_flags |= CGE_IDLUN;
805 				cge.cge_id  = buffer[23];
806 				cge.cge_lun = buffer[22] & 7;
807 			}
808 			if (buffer[9] & 0x80) {
809 				cge.cge_flags |= CGE_PVOLTAG;
810 				memcpy(cge.cge_pvoltag,buffer+28,36);
811 			}
812 			if (buffer[9] & 0x40) {
813 				cge.cge_flags |= CGE_AVOLTAG;
814 				memcpy(cge.cge_avoltag,buffer+64,36);
815 			}
816 		} else if (ch->voltags) {
817 			ch->voltags = 0;
818 			VPRINTK(KERN_INFO, "device has no volume tag support\n");
819 			goto voltag_retry;
820 		}
821 		kfree(buffer);
822 		mutex_unlock(&ch->lock);
823 
824 		if (copy_to_user(argp, &cge, sizeof (cge)))
825 			return -EFAULT;
826 		return result;
827 	}
828 
829 	case CHIOINITELEM:
830 	{
831 		mutex_lock(&ch->lock);
832 		retval = ch_init_elem(ch);
833 		mutex_unlock(&ch->lock);
834 		return retval;
835 	}
836 
837 	case CHIOSVOLTAG:
838 	{
839 		struct changer_set_voltag csv;
840 		int elem;
841 
842 		if (copy_from_user(&csv, argp, sizeof(csv)))
843 			return -EFAULT;
844 
845 		if (0 != ch_checkrange(ch, csv.csv_type, csv.csv_unit)) {
846 			DPRINTK("CHIOSVOLTAG: invalid parameter\n");
847 			return -EBADSLT;
848 		}
849 		elem = ch->firsts[csv.csv_type] + csv.csv_unit;
850 		mutex_lock(&ch->lock);
851 		retval = ch_set_voltag(ch, elem,
852 				       csv.csv_flags & CSV_AVOLTAG,
853 				       csv.csv_flags & CSV_CLEARTAG,
854 				       csv.csv_voltag);
855 		mutex_unlock(&ch->lock);
856 		return retval;
857 	}
858 
859 	default:
860 		return scsi_ioctl(ch->device, cmd, argp);
861 
862 	}
863 }
864 
865 #ifdef CONFIG_COMPAT
866 
867 struct changer_element_status32 {
868 	int		ces_type;
869 	compat_uptr_t	ces_data;
870 };
871 #define CHIOGSTATUS32  _IOW('c', 8,struct changer_element_status32)
872 
873 static long ch_ioctl_compat(struct file * file,
874 			    unsigned int cmd, unsigned long arg)
875 {
876 	scsi_changer *ch = file->private_data;
877 	int retval = scsi_ioctl_block_when_processing_errors(ch->device, cmd,
878 							file->f_flags & O_NDELAY);
879 	if (retval)
880 		return retval;
881 
882 	switch (cmd) {
883 	case CHIOGPARAMS:
884 	case CHIOGVPARAMS:
885 	case CHIOPOSITION:
886 	case CHIOMOVE:
887 	case CHIOEXCHANGE:
888 	case CHIOGELEM:
889 	case CHIOINITELEM:
890 	case CHIOSVOLTAG:
891 		/* compatible */
892 		return ch_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
893 	case CHIOGSTATUS32:
894 	{
895 		struct changer_element_status32 ces32;
896 		unsigned char __user *data;
897 
898 		if (copy_from_user(&ces32, (void __user *)arg, sizeof (ces32)))
899 			return -EFAULT;
900 		if (ces32.ces_type < 0 || ces32.ces_type >= CH_TYPES)
901 			return -EINVAL;
902 
903 		data = compat_ptr(ces32.ces_data);
904 		return ch_gstatus(ch, ces32.ces_type, data);
905 	}
906 	default:
907 		return scsi_compat_ioctl(ch->device, cmd, compat_ptr(arg));
908 
909 	}
910 }
911 #endif
912 
913 /* ------------------------------------------------------------------------ */
914 
915 static int ch_probe(struct device *dev)
916 {
917 	struct scsi_device *sd = to_scsi_device(dev);
918 	struct device *class_dev;
919 	int ret;
920 	scsi_changer *ch;
921 
922 	if (sd->type != TYPE_MEDIUM_CHANGER)
923 		return -ENODEV;
924 
925 	ch = kzalloc(sizeof(*ch), GFP_KERNEL);
926 	if (NULL == ch)
927 		return -ENOMEM;
928 
929 	idr_preload(GFP_KERNEL);
930 	spin_lock(&ch_index_lock);
931 	ret = idr_alloc(&ch_index_idr, ch, 0, CH_MAX_DEVS + 1, GFP_NOWAIT);
932 	spin_unlock(&ch_index_lock);
933 	idr_preload_end();
934 
935 	if (ret < 0) {
936 		if (ret == -ENOSPC)
937 			ret = -ENODEV;
938 		goto free_ch;
939 	}
940 
941 	ch->minor = ret;
942 	sprintf(ch->name,"ch%d",ch->minor);
943 	ret = scsi_device_get(sd);
944 	if (ret) {
945 		sdev_printk(KERN_WARNING, sd, "ch%d: failed to get device\n",
946 			    ch->minor);
947 		goto remove_idr;
948 	}
949 
950 	mutex_init(&ch->lock);
951 	kref_init(&ch->ref);
952 	ch->device = sd;
953 	class_dev = device_create(ch_sysfs_class, dev,
954 				  MKDEV(SCSI_CHANGER_MAJOR, ch->minor), ch,
955 				  "s%s", ch->name);
956 	if (IS_ERR(class_dev)) {
957 		sdev_printk(KERN_WARNING, sd, "ch%d: device_create failed\n",
958 			    ch->minor);
959 		ret = PTR_ERR(class_dev);
960 		goto put_device;
961 	}
962 
963 	mutex_lock(&ch->lock);
964 	ret = ch_readconfig(ch);
965 	if (ret) {
966 		mutex_unlock(&ch->lock);
967 		goto destroy_dev;
968 	}
969 	if (init)
970 		ch_init_elem(ch);
971 
972 	mutex_unlock(&ch->lock);
973 	dev_set_drvdata(dev, ch);
974 	sdev_printk(KERN_INFO, sd, "Attached scsi changer %s\n", ch->name);
975 
976 	return 0;
977 destroy_dev:
978 	device_destroy(ch_sysfs_class, MKDEV(SCSI_CHANGER_MAJOR, ch->minor));
979 put_device:
980 	scsi_device_put(sd);
981 remove_idr:
982 	idr_remove(&ch_index_idr, ch->minor);
983 free_ch:
984 	kfree(ch);
985 	return ret;
986 }
987 
988 static int ch_remove(struct device *dev)
989 {
990 	scsi_changer *ch = dev_get_drvdata(dev);
991 
992 	spin_lock(&ch_index_lock);
993 	idr_remove(&ch_index_idr, ch->minor);
994 	dev_set_drvdata(dev, NULL);
995 	spin_unlock(&ch_index_lock);
996 
997 	device_destroy(ch_sysfs_class, MKDEV(SCSI_CHANGER_MAJOR,ch->minor));
998 	scsi_device_put(ch->device);
999 	kref_put(&ch->ref, ch_destroy);
1000 	return 0;
1001 }
1002 
1003 static struct scsi_driver ch_template = {
1004 	.gendrv     	= {
1005 		.name	= "ch",
1006 		.owner	= THIS_MODULE,
1007 		.probe  = ch_probe,
1008 		.remove = ch_remove,
1009 	},
1010 };
1011 
1012 static const struct file_operations changer_fops = {
1013 	.owner		= THIS_MODULE,
1014 	.open		= ch_open,
1015 	.release	= ch_release,
1016 	.unlocked_ioctl	= ch_ioctl,
1017 #ifdef CONFIG_COMPAT
1018 	.compat_ioctl	= ch_ioctl_compat,
1019 #endif
1020 	.llseek		= noop_llseek,
1021 };
1022 
1023 static int __init init_ch_module(void)
1024 {
1025 	int rc;
1026 
1027 	printk(KERN_INFO "SCSI Media Changer driver v" VERSION " \n");
1028         ch_sysfs_class = class_create(THIS_MODULE, "scsi_changer");
1029         if (IS_ERR(ch_sysfs_class)) {
1030 		rc = PTR_ERR(ch_sysfs_class);
1031 		return rc;
1032         }
1033 	rc = register_chrdev(SCSI_CHANGER_MAJOR,"ch",&changer_fops);
1034 	if (rc < 0) {
1035 		printk("Unable to get major %d for SCSI-Changer\n",
1036 		       SCSI_CHANGER_MAJOR);
1037 		goto fail1;
1038 	}
1039 	rc = scsi_register_driver(&ch_template.gendrv);
1040 	if (rc < 0)
1041 		goto fail2;
1042 	return 0;
1043 
1044  fail2:
1045 	unregister_chrdev(SCSI_CHANGER_MAJOR, "ch");
1046  fail1:
1047 	class_destroy(ch_sysfs_class);
1048 	return rc;
1049 }
1050 
1051 static void __exit exit_ch_module(void)
1052 {
1053 	scsi_unregister_driver(&ch_template.gendrv);
1054 	unregister_chrdev(SCSI_CHANGER_MAJOR, "ch");
1055 	class_destroy(ch_sysfs_class);
1056 	idr_destroy(&ch_index_idr);
1057 }
1058 
1059 module_init(init_ch_module);
1060 module_exit(exit_ch_module);
1061