xref: /openbmc/linux/drivers/usb/storage/datafab.c (revision 22246614)
1 /* Driver for Datafab USB Compact Flash reader
2  *
3  * $Id: datafab.c,v 1.7 2002/02/25 00:40:13 mdharm Exp $
4  *
5  * datafab driver v0.1:
6  *
7  * First release
8  *
9  * Current development and maintenance by:
10  *   (c) 2000 Jimmie Mayfield (mayfield+datafab@sackheads.org)
11  *
12  *   Many thanks to Robert Baruch for the SanDisk SmartMedia reader driver
13  *   which I used as a template for this driver.
14  *
15  *   Some bugfixes and scatter-gather code by Gregory P. Smith
16  *   (greg-usb@electricrain.com)
17  *
18  *   Fix for media change by Joerg Schneider (js@joergschneider.com)
19  *
20  * Other contributors:
21  *   (c) 2002 Alan Stern <stern@rowland.org>
22  *
23  * This program is free software; you can redistribute it and/or modify it
24  * under the terms of the GNU General Public License as published by the
25  * Free Software Foundation; either version 2, or (at your option) any
26  * later version.
27  *
28  * This program is distributed in the hope that it will be useful, but
29  * WITHOUT ANY WARRANTY; without even the implied warranty of
30  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
31  * General Public License for more details.
32  *
33  * You should have received a copy of the GNU General Public License along
34  * with this program; if not, write to the Free Software Foundation, Inc.,
35  * 675 Mass Ave, Cambridge, MA 02139, USA.
36  */
37 
38 /*
39  * This driver attempts to support USB CompactFlash reader/writer devices
40  * based on Datafab USB-to-ATA chips.  It was specifically developed for the
41  * Datafab MDCFE-B USB CompactFlash reader but has since been found to work
42  * with a variety of Datafab-based devices from a number of manufacturers.
43  * I've received a report of this driver working with a Datafab-based
44  * SmartMedia device though please be aware that I'm personally unable to
45  * test SmartMedia support.
46  *
47  * This driver supports reading and writing.  If you're truly paranoid,
48  * however, you can force the driver into a write-protected state by setting
49  * the WP enable bits in datafab_handle_mode_sense().  See the comments
50  * in that routine.
51  */
52 
53 #include <linux/errno.h>
54 #include <linux/slab.h>
55 
56 #include <scsi/scsi.h>
57 #include <scsi/scsi_cmnd.h>
58 
59 #include "usb.h"
60 #include "transport.h"
61 #include "protocol.h"
62 #include "debug.h"
63 #include "datafab.h"
64 
65 static int datafab_determine_lun(struct us_data *us,
66 				 struct datafab_info *info);
67 
68 
69 static inline int
70 datafab_bulk_read(struct us_data *us, unsigned char *data, unsigned int len) {
71 	if (len == 0)
72 		return USB_STOR_XFER_GOOD;
73 
74 	US_DEBUGP("datafab_bulk_read:  len = %d\n", len);
75 	return usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe,
76 			data, len, NULL);
77 }
78 
79 
80 static inline int
81 datafab_bulk_write(struct us_data *us, unsigned char *data, unsigned int len) {
82 	if (len == 0)
83 		return USB_STOR_XFER_GOOD;
84 
85 	US_DEBUGP("datafab_bulk_write:  len = %d\n", len);
86 	return usb_stor_bulk_transfer_buf(us, us->send_bulk_pipe,
87 			data, len, NULL);
88 }
89 
90 
91 static int datafab_read_data(struct us_data *us,
92 			     struct datafab_info *info,
93 			     u32 sector,
94 			     u32 sectors)
95 {
96 	unsigned char *command = us->iobuf;
97 	unsigned char *buffer;
98 	unsigned char  thistime;
99 	unsigned int totallen, alloclen;
100 	int len, result;
101 	unsigned int sg_offset = 0;
102 	struct scatterlist *sg = NULL;
103 
104 	// we're working in LBA mode.  according to the ATA spec,
105 	// we can support up to 28-bit addressing.  I don't know if Datafab
106 	// supports beyond 24-bit addressing.  It's kind of hard to test
107 	// since it requires > 8GB CF card.
108 	//
109 	if (sectors > 0x0FFFFFFF)
110 		return USB_STOR_TRANSPORT_ERROR;
111 
112 	if (info->lun == -1) {
113 		result = datafab_determine_lun(us, info);
114 		if (result != USB_STOR_TRANSPORT_GOOD)
115 			return result;
116 	}
117 
118 	totallen = sectors * info->ssize;
119 
120 	// Since we don't read more than 64 KB at a time, we have to create
121 	// a bounce buffer and move the data a piece at a time between the
122 	// bounce buffer and the actual transfer buffer.
123 
124 	alloclen = min(totallen, 65536u);
125 	buffer = kmalloc(alloclen, GFP_NOIO);
126 	if (buffer == NULL)
127 		return USB_STOR_TRANSPORT_ERROR;
128 
129 	do {
130 		// loop, never allocate or transfer more than 64k at once
131 		// (min(128k, 255*info->ssize) is the real limit)
132 
133 		len = min(totallen, alloclen);
134 		thistime = (len / info->ssize) & 0xff;
135 
136 		command[0] = 0;
137 		command[1] = thistime;
138 		command[2] = sector & 0xFF;
139 		command[3] = (sector >> 8) & 0xFF;
140 		command[4] = (sector >> 16) & 0xFF;
141 
142 		command[5] = 0xE0 + (info->lun << 4);
143 		command[5] |= (sector >> 24) & 0x0F;
144 		command[6] = 0x20;
145 		command[7] = 0x01;
146 
147 		// send the read command
148 		result = datafab_bulk_write(us, command, 8);
149 		if (result != USB_STOR_XFER_GOOD)
150 			goto leave;
151 
152 		// read the result
153 		result = datafab_bulk_read(us, buffer, len);
154 		if (result != USB_STOR_XFER_GOOD)
155 			goto leave;
156 
157 		// Store the data in the transfer buffer
158 		usb_stor_access_xfer_buf(buffer, len, us->srb,
159 				 &sg, &sg_offset, TO_XFER_BUF);
160 
161 		sector += thistime;
162 		totallen -= len;
163 	} while (totallen > 0);
164 
165 	kfree(buffer);
166 	return USB_STOR_TRANSPORT_GOOD;
167 
168  leave:
169 	kfree(buffer);
170 	return USB_STOR_TRANSPORT_ERROR;
171 }
172 
173 
174 static int datafab_write_data(struct us_data *us,
175 			      struct datafab_info *info,
176 			      u32 sector,
177 			      u32 sectors)
178 {
179 	unsigned char *command = us->iobuf;
180 	unsigned char *reply = us->iobuf;
181 	unsigned char *buffer;
182 	unsigned char thistime;
183 	unsigned int totallen, alloclen;
184 	int len, result;
185 	unsigned int sg_offset = 0;
186 	struct scatterlist *sg = NULL;
187 
188 	// we're working in LBA mode.  according to the ATA spec,
189 	// we can support up to 28-bit addressing.  I don't know if Datafab
190 	// supports beyond 24-bit addressing.  It's kind of hard to test
191 	// since it requires > 8GB CF card.
192 	//
193 	if (sectors > 0x0FFFFFFF)
194 		return USB_STOR_TRANSPORT_ERROR;
195 
196 	if (info->lun == -1) {
197 		result = datafab_determine_lun(us, info);
198 		if (result != USB_STOR_TRANSPORT_GOOD)
199 			return result;
200 	}
201 
202 	totallen = sectors * info->ssize;
203 
204 	// Since we don't write more than 64 KB at a time, we have to create
205 	// a bounce buffer and move the data a piece at a time between the
206 	// bounce buffer and the actual transfer buffer.
207 
208 	alloclen = min(totallen, 65536u);
209 	buffer = kmalloc(alloclen, GFP_NOIO);
210 	if (buffer == NULL)
211 		return USB_STOR_TRANSPORT_ERROR;
212 
213 	do {
214 		// loop, never allocate or transfer more than 64k at once
215 		// (min(128k, 255*info->ssize) is the real limit)
216 
217 		len = min(totallen, alloclen);
218 		thistime = (len / info->ssize) & 0xff;
219 
220 		// Get the data from the transfer buffer
221 		usb_stor_access_xfer_buf(buffer, len, us->srb,
222 				&sg, &sg_offset, FROM_XFER_BUF);
223 
224 		command[0] = 0;
225 		command[1] = thistime;
226 		command[2] = sector & 0xFF;
227 		command[3] = (sector >> 8) & 0xFF;
228 		command[4] = (sector >> 16) & 0xFF;
229 
230 		command[5] = 0xE0 + (info->lun << 4);
231 		command[5] |= (sector >> 24) & 0x0F;
232 		command[6] = 0x30;
233 		command[7] = 0x02;
234 
235 		// send the command
236 		result = datafab_bulk_write(us, command, 8);
237 		if (result != USB_STOR_XFER_GOOD)
238 			goto leave;
239 
240 		// send the data
241 		result = datafab_bulk_write(us, buffer, len);
242 		if (result != USB_STOR_XFER_GOOD)
243 			goto leave;
244 
245 		// read the result
246 		result = datafab_bulk_read(us, reply, 2);
247 		if (result != USB_STOR_XFER_GOOD)
248 			goto leave;
249 
250 		if (reply[0] != 0x50 && reply[1] != 0) {
251 			US_DEBUGP("datafab_write_data:  Gah! "
252 				  "write return code: %02x %02x\n",
253 				  reply[0], reply[1]);
254 			result = USB_STOR_TRANSPORT_ERROR;
255 			goto leave;
256 		}
257 
258 		sector += thistime;
259 		totallen -= len;
260 	} while (totallen > 0);
261 
262 	kfree(buffer);
263 	return USB_STOR_TRANSPORT_GOOD;
264 
265  leave:
266 	kfree(buffer);
267 	return USB_STOR_TRANSPORT_ERROR;
268 }
269 
270 
271 static int datafab_determine_lun(struct us_data *us,
272 				 struct datafab_info *info)
273 {
274 	// Dual-slot readers can be thought of as dual-LUN devices.
275 	// We need to determine which card slot is being used.
276 	// We'll send an IDENTIFY DEVICE command and see which LUN responds...
277 	//
278 	// There might be a better way of doing this?
279 
280 	static unsigned char scommand[8] = { 0, 1, 0, 0, 0, 0xa0, 0xec, 1 };
281 	unsigned char *command = us->iobuf;
282 	unsigned char *buf;
283 	int count = 0, rc;
284 
285 	if (!us || !info)
286 		return USB_STOR_TRANSPORT_ERROR;
287 
288 	memcpy(command, scommand, 8);
289 	buf = kmalloc(512, GFP_NOIO);
290 	if (!buf)
291 		return USB_STOR_TRANSPORT_ERROR;
292 
293 	US_DEBUGP("datafab_determine_lun:  locating...\n");
294 
295 	// we'll try 3 times before giving up...
296 	//
297 	while (count++ < 3) {
298 		command[5] = 0xa0;
299 
300 		rc = datafab_bulk_write(us, command, 8);
301 		if (rc != USB_STOR_XFER_GOOD) {
302 			rc = USB_STOR_TRANSPORT_ERROR;
303 			goto leave;
304 		}
305 
306 		rc = datafab_bulk_read(us, buf, 512);
307 		if (rc == USB_STOR_XFER_GOOD) {
308 			info->lun = 0;
309 			rc = USB_STOR_TRANSPORT_GOOD;
310 			goto leave;
311 		}
312 
313 		command[5] = 0xb0;
314 
315 		rc = datafab_bulk_write(us, command, 8);
316 		if (rc != USB_STOR_XFER_GOOD) {
317 			rc = USB_STOR_TRANSPORT_ERROR;
318 			goto leave;
319 		}
320 
321 		rc = datafab_bulk_read(us, buf, 512);
322 		if (rc == USB_STOR_XFER_GOOD) {
323 			info->lun = 1;
324 			rc = USB_STOR_TRANSPORT_GOOD;
325 			goto leave;
326 		}
327 
328 		msleep(20);
329 	}
330 
331 	rc = USB_STOR_TRANSPORT_ERROR;
332 
333  leave:
334 	kfree(buf);
335 	return rc;
336 }
337 
338 static int datafab_id_device(struct us_data *us,
339 			     struct datafab_info *info)
340 {
341 	// this is a variation of the ATA "IDENTIFY DEVICE" command...according
342 	// to the ATA spec, 'Sector Count' isn't used but the Windows driver
343 	// sets this bit so we do too...
344 	//
345 	static unsigned char scommand[8] = { 0, 1, 0, 0, 0, 0xa0, 0xec, 1 };
346 	unsigned char *command = us->iobuf;
347 	unsigned char *reply;
348 	int rc;
349 
350 	if (!us || !info)
351 		return USB_STOR_TRANSPORT_ERROR;
352 
353 	if (info->lun == -1) {
354 		rc = datafab_determine_lun(us, info);
355 		if (rc != USB_STOR_TRANSPORT_GOOD)
356 			return rc;
357 	}
358 
359 	memcpy(command, scommand, 8);
360 	reply = kmalloc(512, GFP_NOIO);
361 	if (!reply)
362 		return USB_STOR_TRANSPORT_ERROR;
363 
364 	command[5] += (info->lun << 4);
365 
366 	rc = datafab_bulk_write(us, command, 8);
367 	if (rc != USB_STOR_XFER_GOOD) {
368 		rc = USB_STOR_TRANSPORT_ERROR;
369 		goto leave;
370 	}
371 
372 	// we'll go ahead and extract the media capacity while we're here...
373 	//
374 	rc = datafab_bulk_read(us, reply, 512);
375 	if (rc == USB_STOR_XFER_GOOD) {
376 		// capacity is at word offset 57-58
377 		//
378 		info->sectors = ((u32)(reply[117]) << 24) |
379 				((u32)(reply[116]) << 16) |
380 				((u32)(reply[115]) <<  8) |
381 				((u32)(reply[114])      );
382 		rc = USB_STOR_TRANSPORT_GOOD;
383 		goto leave;
384 	}
385 
386 	rc = USB_STOR_TRANSPORT_ERROR;
387 
388  leave:
389 	kfree(reply);
390 	return rc;
391 }
392 
393 
394 static int datafab_handle_mode_sense(struct us_data *us,
395 				     struct scsi_cmnd * srb,
396 				     int sense_6)
397 {
398 	static unsigned char rw_err_page[12] = {
399 		0x1, 0xA, 0x21, 1, 0, 0, 0, 0, 1, 0, 0, 0
400 	};
401 	static unsigned char cache_page[12] = {
402 		0x8, 0xA, 0x1, 0, 0, 0, 0, 0, 0, 0, 0, 0
403 	};
404 	static unsigned char rbac_page[12] = {
405 		0x1B, 0xA, 0, 0x81, 0, 0, 0, 0, 0, 0, 0, 0
406 	};
407 	static unsigned char timer_page[8] = {
408 		0x1C, 0x6, 0, 0, 0, 0
409 	};
410 	unsigned char pc, page_code;
411 	unsigned int i = 0;
412 	struct datafab_info *info = (struct datafab_info *) (us->extra);
413 	unsigned char *ptr = us->iobuf;
414 
415 	// most of this stuff is just a hack to get things working.  the
416 	// datafab reader doesn't present a SCSI interface so we
417 	// fudge the SCSI commands...
418 	//
419 
420 	pc = srb->cmnd[2] >> 6;
421 	page_code = srb->cmnd[2] & 0x3F;
422 
423 	switch (pc) {
424 	   case 0x0:
425 		US_DEBUGP("datafab_handle_mode_sense:  Current values\n");
426 		break;
427 	   case 0x1:
428 		US_DEBUGP("datafab_handle_mode_sense:  Changeable values\n");
429 		break;
430 	   case 0x2:
431 		US_DEBUGP("datafab_handle_mode_sense:  Default values\n");
432 		break;
433 	   case 0x3:
434 		US_DEBUGP("datafab_handle_mode_sense:  Saves values\n");
435 		break;
436 	}
437 
438 	memset(ptr, 0, 8);
439 	if (sense_6) {
440 		ptr[2] = 0x00;		// WP enable: 0x80
441 		i = 4;
442 	} else {
443 		ptr[3] = 0x00;		// WP enable: 0x80
444 		i = 8;
445 	}
446 
447 	switch (page_code) {
448 	   default:
449 		// vendor-specific mode
450 		info->sense_key = 0x05;
451 		info->sense_asc = 0x24;
452 		info->sense_ascq = 0x00;
453 		return USB_STOR_TRANSPORT_FAILED;
454 
455 	   case 0x1:
456 		memcpy(ptr + i, rw_err_page, sizeof(rw_err_page));
457 		i += sizeof(rw_err_page);
458 		break;
459 
460 	   case 0x8:
461 		memcpy(ptr + i, cache_page, sizeof(cache_page));
462 		i += sizeof(cache_page);
463 		break;
464 
465 	   case 0x1B:
466 		memcpy(ptr + i, rbac_page, sizeof(rbac_page));
467 		i += sizeof(rbac_page);
468 		break;
469 
470 	   case 0x1C:
471 		memcpy(ptr + i, timer_page, sizeof(timer_page));
472 		i += sizeof(timer_page);
473 		break;
474 
475 	   case 0x3F:		// retrieve all pages
476 		memcpy(ptr + i, timer_page, sizeof(timer_page));
477 		i += sizeof(timer_page);
478 		memcpy(ptr + i, rbac_page, sizeof(rbac_page));
479 		i += sizeof(rbac_page);
480 		memcpy(ptr + i, cache_page, sizeof(cache_page));
481 		i += sizeof(cache_page);
482 		memcpy(ptr + i, rw_err_page, sizeof(rw_err_page));
483 		i += sizeof(rw_err_page);
484 		break;
485 	}
486 
487 	if (sense_6)
488 		ptr[0] = i - 1;
489 	else
490 		((__be16 *) ptr)[0] = cpu_to_be16(i - 2);
491 	usb_stor_set_xfer_buf(ptr, i, srb);
492 
493 	return USB_STOR_TRANSPORT_GOOD;
494 }
495 
496 static void datafab_info_destructor(void *extra)
497 {
498 	// this routine is a placeholder...
499 	// currently, we don't allocate any extra memory so we're okay
500 }
501 
502 
503 // Transport for the Datafab MDCFE-B
504 //
505 int datafab_transport(struct scsi_cmnd * srb, struct us_data *us)
506 {
507 	struct datafab_info *info;
508 	int rc;
509 	unsigned long block, blocks;
510 	unsigned char *ptr = us->iobuf;
511 	static unsigned char inquiry_reply[8] = {
512 		0x00, 0x80, 0x00, 0x01, 0x1F, 0x00, 0x00, 0x00
513 	};
514 
515 	if (!us->extra) {
516 		us->extra = kzalloc(sizeof(struct datafab_info), GFP_NOIO);
517 		if (!us->extra) {
518 			US_DEBUGP("datafab_transport:  Gah! "
519 				  "Can't allocate storage for Datafab info struct!\n");
520 			return USB_STOR_TRANSPORT_ERROR;
521 		}
522 		us->extra_destructor = datafab_info_destructor;
523   		((struct datafab_info *)us->extra)->lun = -1;
524 	}
525 
526 	info = (struct datafab_info *) (us->extra);
527 
528 	if (srb->cmnd[0] == INQUIRY) {
529 		US_DEBUGP("datafab_transport:  INQUIRY.  Returning bogus response");
530 		memcpy(ptr, inquiry_reply, sizeof(inquiry_reply));
531 		fill_inquiry_response(us, ptr, 36);
532 		return USB_STOR_TRANSPORT_GOOD;
533 	}
534 
535 	if (srb->cmnd[0] == READ_CAPACITY) {
536 		info->ssize = 0x200;  // hard coded 512 byte sectors as per ATA spec
537 		rc = datafab_id_device(us, info);
538 		if (rc != USB_STOR_TRANSPORT_GOOD)
539 			return rc;
540 
541 		US_DEBUGP("datafab_transport:  READ_CAPACITY:  %ld sectors, %ld bytes per sector\n",
542 			  info->sectors, info->ssize);
543 
544 		// build the reply
545 		// we need the last sector, not the number of sectors
546 		((__be32 *) ptr)[0] = cpu_to_be32(info->sectors - 1);
547 		((__be32 *) ptr)[1] = cpu_to_be32(info->ssize);
548 		usb_stor_set_xfer_buf(ptr, 8, srb);
549 
550 		return USB_STOR_TRANSPORT_GOOD;
551 	}
552 
553 	if (srb->cmnd[0] == MODE_SELECT_10) {
554 		US_DEBUGP("datafab_transport:  Gah! MODE_SELECT_10.\n");
555 		return USB_STOR_TRANSPORT_ERROR;
556 	}
557 
558 	// don't bother implementing READ_6 or WRITE_6.
559 	//
560 	if (srb->cmnd[0] == READ_10) {
561 		block = ((u32)(srb->cmnd[2]) << 24) | ((u32)(srb->cmnd[3]) << 16) |
562 			((u32)(srb->cmnd[4]) <<  8) | ((u32)(srb->cmnd[5]));
563 
564 		blocks = ((u32)(srb->cmnd[7]) << 8) | ((u32)(srb->cmnd[8]));
565 
566 		US_DEBUGP("datafab_transport:  READ_10: read block 0x%04lx  count %ld\n", block, blocks);
567 		return datafab_read_data(us, info, block, blocks);
568 	}
569 
570 	if (srb->cmnd[0] == READ_12) {
571 		// we'll probably never see a READ_12 but we'll do it anyway...
572 		//
573 		block = ((u32)(srb->cmnd[2]) << 24) | ((u32)(srb->cmnd[3]) << 16) |
574 			((u32)(srb->cmnd[4]) <<  8) | ((u32)(srb->cmnd[5]));
575 
576 		blocks = ((u32)(srb->cmnd[6]) << 24) | ((u32)(srb->cmnd[7]) << 16) |
577 			 ((u32)(srb->cmnd[8]) <<  8) | ((u32)(srb->cmnd[9]));
578 
579 		US_DEBUGP("datafab_transport:  READ_12: read block 0x%04lx  count %ld\n", block, blocks);
580 		return datafab_read_data(us, info, block, blocks);
581 	}
582 
583 	if (srb->cmnd[0] == WRITE_10) {
584 		block = ((u32)(srb->cmnd[2]) << 24) | ((u32)(srb->cmnd[3]) << 16) |
585 			((u32)(srb->cmnd[4]) <<  8) | ((u32)(srb->cmnd[5]));
586 
587 		blocks = ((u32)(srb->cmnd[7]) << 8) | ((u32)(srb->cmnd[8]));
588 
589 		US_DEBUGP("datafab_transport:  WRITE_10: write block 0x%04lx  count %ld\n", block, blocks);
590 		return datafab_write_data(us, info, block, blocks);
591 	}
592 
593 	if (srb->cmnd[0] == WRITE_12) {
594 		// we'll probably never see a WRITE_12 but we'll do it anyway...
595 		//
596 		block = ((u32)(srb->cmnd[2]) << 24) | ((u32)(srb->cmnd[3]) << 16) |
597 			((u32)(srb->cmnd[4]) <<  8) | ((u32)(srb->cmnd[5]));
598 
599 		blocks = ((u32)(srb->cmnd[6]) << 24) | ((u32)(srb->cmnd[7]) << 16) |
600 			 ((u32)(srb->cmnd[8]) <<  8) | ((u32)(srb->cmnd[9]));
601 
602 		US_DEBUGP("datafab_transport:  WRITE_12: write block 0x%04lx  count %ld\n", block, blocks);
603 		return datafab_write_data(us, info, block, blocks);
604 	}
605 
606 	if (srb->cmnd[0] == TEST_UNIT_READY) {
607 		US_DEBUGP("datafab_transport:  TEST_UNIT_READY.\n");
608 		return datafab_id_device(us, info);
609 	}
610 
611 	if (srb->cmnd[0] == REQUEST_SENSE) {
612 		US_DEBUGP("datafab_transport:  REQUEST_SENSE.  Returning faked response\n");
613 
614 		// this response is pretty bogus right now.  eventually if necessary
615 		// we can set the correct sense data.  so far though it hasn't been
616 		// necessary
617 		//
618 		memset(ptr, 0, 18);
619 		ptr[0] = 0xF0;
620 		ptr[2] = info->sense_key;
621 		ptr[7] = 11;
622 		ptr[12] = info->sense_asc;
623 		ptr[13] = info->sense_ascq;
624 		usb_stor_set_xfer_buf(ptr, 18, srb);
625 
626 		return USB_STOR_TRANSPORT_GOOD;
627 	}
628 
629 	if (srb->cmnd[0] == MODE_SENSE) {
630 		US_DEBUGP("datafab_transport:  MODE_SENSE_6 detected\n");
631 		return datafab_handle_mode_sense(us, srb, 1);
632 	}
633 
634 	if (srb->cmnd[0] == MODE_SENSE_10) {
635 		US_DEBUGP("datafab_transport:  MODE_SENSE_10 detected\n");
636 		return datafab_handle_mode_sense(us, srb, 0);
637 	}
638 
639 	if (srb->cmnd[0] == ALLOW_MEDIUM_REMOVAL) {
640 		// sure.  whatever.  not like we can stop the user from
641 		// popping the media out of the device (no locking doors, etc)
642 		//
643 		return USB_STOR_TRANSPORT_GOOD;
644 	}
645 
646 	if (srb->cmnd[0] == START_STOP) {
647 		/* this is used by sd.c'check_scsidisk_media_change to detect
648 		   media change */
649 		US_DEBUGP("datafab_transport:  START_STOP.\n");
650 		/* the first datafab_id_device after a media change returns
651 		   an error (determined experimentally) */
652 		rc = datafab_id_device(us, info);
653 		if (rc == USB_STOR_TRANSPORT_GOOD) {
654 			info->sense_key = NO_SENSE;
655 			srb->result = SUCCESS;
656 		} else {
657 			info->sense_key = UNIT_ATTENTION;
658 			srb->result = SAM_STAT_CHECK_CONDITION;
659 		}
660 		return rc;
661 	}
662 
663 	US_DEBUGP("datafab_transport:  Gah! Unknown command: %d (0x%x)\n",
664 		  srb->cmnd[0], srb->cmnd[0]);
665 	info->sense_key = 0x05;
666 	info->sense_asc = 0x20;
667 	info->sense_ascq = 0x00;
668 	return USB_STOR_TRANSPORT_FAILED;
669 }
670