xref: /OK3568_Linux_fs/kernel/drivers/usb/storage/scsiglue.c (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Driver for USB Mass Storage compliant devices
4  * SCSI layer glue code
5  *
6  * Current development and maintenance by:
7  *   (c) 1999-2002 Matthew Dharm (mdharm-usb@one-eyed-alien.net)
8  *
9  * Developed with the assistance of:
10  *   (c) 2000 David L. Brown, Jr. (usb-storage@davidb.org)
11  *   (c) 2000 Stephen J. Gowdy (SGowdy@lbl.gov)
12  *
13  * Initial work by:
14  *   (c) 1999 Michael Gee (michael@linuxspecific.com)
15  *
16  * This driver is based on the 'USB Mass Storage Class' document. This
17  * describes in detail the protocol used to communicate with such
18  * devices.  Clearly, the designers had SCSI and ATAPI commands in
19  * mind when they created this document.  The commands are all very
20  * similar to commands in the SCSI-II and ATAPI specifications.
21  *
22  * It is important to note that in a number of cases this class
23  * exhibits class-specific exemptions from the USB specification.
24  * Notably the usage of NAK, STALL and ACK differs from the norm, in
25  * that they are used to communicate wait, failed and OK on commands.
26  *
27  * Also, for certain devices, the interrupt endpoint is used to convey
28  * status of a command.
29  */
30 
31 #include <linux/blkdev.h>
32 #include <linux/dma-mapping.h>
33 #include <linux/module.h>
34 #include <linux/mutex.h>
35 
36 #include <scsi/scsi.h>
37 #include <scsi/scsi_cmnd.h>
38 #include <scsi/scsi_devinfo.h>
39 #include <scsi/scsi_device.h>
40 #include <scsi/scsi_eh.h>
41 
42 #include "usb.h"
43 #include <linux/usb/hcd.h>
44 #include "scsiglue.h"
45 #include "debug.h"
46 #include "transport.h"
47 #include "protocol.h"
48 
49 /*
50  * Vendor IDs for companies that seem to include the READ CAPACITY bug
51  * in all their devices
52  */
53 #define VENDOR_ID_NOKIA		0x0421
54 #define VENDOR_ID_NIKON		0x04b0
55 #define VENDOR_ID_PENTAX	0x0a17
56 #define VENDOR_ID_MOTOROLA	0x22b8
57 
58 /***********************************************************************
59  * Host functions
60  ***********************************************************************/
61 
host_info(struct Scsi_Host * host)62 static const char* host_info(struct Scsi_Host *host)
63 {
64 	struct us_data *us = host_to_us(host);
65 	return us->scsi_name;
66 }
67 
slave_alloc(struct scsi_device * sdev)68 static int slave_alloc (struct scsi_device *sdev)
69 {
70 	struct us_data *us = host_to_us(sdev->host);
71 
72 	/*
73 	 * Set the INQUIRY transfer length to 36.  We don't use any of
74 	 * the extra data and many devices choke if asked for more or
75 	 * less than 36 bytes.
76 	 */
77 	sdev->inquiry_len = 36;
78 
79 	/*
80 	 * Some host controllers may have alignment requirements.
81 	 * We'll play it safe by requiring 512-byte alignment always.
82 	 */
83 	blk_queue_update_dma_alignment(sdev->request_queue, (512 - 1));
84 
85 	/* Tell the SCSI layer if we know there is more than one LUN */
86 	if (us->protocol == USB_PR_BULK && us->max_lun > 0)
87 		sdev->sdev_bflags |= BLIST_FORCELUN;
88 
89 	return 0;
90 }
91 
slave_configure(struct scsi_device * sdev)92 static int slave_configure(struct scsi_device *sdev)
93 {
94 	struct us_data *us = host_to_us(sdev->host);
95 	struct device *dev = us->pusb_dev->bus->sysdev;
96 
97 	/*
98 	 * Many devices have trouble transferring more than 32KB at a time,
99 	 * while others have trouble with more than 64K. At this time we
100 	 * are limiting both to 32K (64 sectores).
101 	 */
102 	if (us->fflags & (US_FL_MAX_SECTORS_64 | US_FL_MAX_SECTORS_MIN)) {
103 		unsigned int max_sectors = 64;
104 
105 		if (le16_to_cpu(us->pusb_dev->descriptor.idVendor) == 0x05e3 &&
106 		    le16_to_cpu(us->pusb_dev->descriptor.idProduct) == 0x0749)
107 			max_sectors = 128;
108 
109 		if (us->fflags & US_FL_MAX_SECTORS_MIN)
110 			max_sectors = PAGE_SIZE >> 9;
111 		if (queue_max_hw_sectors(sdev->request_queue) > max_sectors)
112 			blk_queue_max_hw_sectors(sdev->request_queue,
113 					      max_sectors);
114 	} else if (sdev->type == TYPE_TAPE) {
115 		/*
116 		 * Tapes need much higher max_sector limits, so just
117 		 * raise it to the maximum possible (4 GB / 512) and
118 		 * let the queue segment size sort out the real limit.
119 		 */
120 		blk_queue_max_hw_sectors(sdev->request_queue, 0x7FFFFF);
121 	} else if (us->pusb_dev->speed >= USB_SPEED_SUPER) {
122 		/*
123 		 * USB3 devices will be limited to 2048 sectors. This gives us
124 		 * better throughput on most devices.
125 		 */
126 		blk_queue_max_hw_sectors(sdev->request_queue, 2048);
127 	}
128 
129 	/*
130 	 * The max_hw_sectors should be up to maximum size of a mapping for
131 	 * the device. Otherwise, a DMA API might fail on swiotlb environment.
132 	 */
133 	blk_queue_max_hw_sectors(sdev->request_queue,
134 		min_t(size_t, queue_max_hw_sectors(sdev->request_queue),
135 		      dma_max_mapping_size(dev) >> SECTOR_SHIFT));
136 
137 	/*
138 	 * Some USB host controllers can't do DMA; they have to use PIO.
139 	 * For such controllers we need to make sure the block layer sets
140 	 * up bounce buffers in addressable memory.
141 	 */
142 	if (!hcd_uses_dma(bus_to_hcd(us->pusb_dev->bus)) ||
143 			(bus_to_hcd(us->pusb_dev->bus)->localmem_pool != NULL))
144 		blk_queue_bounce_limit(sdev->request_queue, BLK_BOUNCE_HIGH);
145 
146 	/*
147 	 * We can't put these settings in slave_alloc() because that gets
148 	 * called before the device type is known.  Consequently these
149 	 * settings can't be overridden via the scsi devinfo mechanism.
150 	 */
151 	if (sdev->type == TYPE_DISK) {
152 
153 		/*
154 		 * Some vendors seem to put the READ CAPACITY bug into
155 		 * all their devices -- primarily makers of cell phones
156 		 * and digital cameras.  Since these devices always use
157 		 * flash media and can be expected to have an even number
158 		 * of sectors, we will always enable the CAPACITY_HEURISTICS
159 		 * flag unless told otherwise.
160 		 */
161 		switch (le16_to_cpu(us->pusb_dev->descriptor.idVendor)) {
162 		case VENDOR_ID_NOKIA:
163 		case VENDOR_ID_NIKON:
164 		case VENDOR_ID_PENTAX:
165 		case VENDOR_ID_MOTOROLA:
166 			if (!(us->fflags & (US_FL_FIX_CAPACITY |
167 					US_FL_CAPACITY_OK)))
168 				us->fflags |= US_FL_CAPACITY_HEURISTICS;
169 			break;
170 		}
171 
172 		/*
173 		 * Disk-type devices use MODE SENSE(6) if the protocol
174 		 * (SubClass) is Transparent SCSI, otherwise they use
175 		 * MODE SENSE(10).
176 		 */
177 		if (us->subclass != USB_SC_SCSI && us->subclass != USB_SC_CYP_ATACB)
178 			sdev->use_10_for_ms = 1;
179 
180 		/*
181 		 *Many disks only accept MODE SENSE transfer lengths of
182 		 * 192 bytes (that's what Windows uses).
183 		 */
184 		sdev->use_192_bytes_for_3f = 1;
185 
186 		/*
187 		 * Some devices don't like MODE SENSE with page=0x3f,
188 		 * which is the command used for checking if a device
189 		 * is write-protected.  Now that we tell the sd driver
190 		 * to do a 192-byte transfer with this command the
191 		 * majority of devices work fine, but a few still can't
192 		 * handle it.  The sd driver will simply assume those
193 		 * devices are write-enabled.
194 		 */
195 		if (us->fflags & US_FL_NO_WP_DETECT)
196 			sdev->skip_ms_page_3f = 1;
197 
198 		/*
199 		 * A number of devices have problems with MODE SENSE for
200 		 * page x08, so we will skip it.
201 		 */
202 		sdev->skip_ms_page_8 = 1;
203 
204 		/*
205 		 * Some devices don't handle VPD pages correctly, so skip vpd
206 		 * pages if not forced by SCSI layer.
207 		 */
208 		sdev->skip_vpd_pages = !sdev->try_vpd_pages;
209 
210 		/* Do not attempt to use REPORT SUPPORTED OPERATION CODES */
211 		sdev->no_report_opcodes = 1;
212 
213 		/* Do not attempt to use WRITE SAME */
214 		sdev->no_write_same = 1;
215 
216 		/*
217 		 * Some disks return the total number of blocks in response
218 		 * to READ CAPACITY rather than the highest block number.
219 		 * If this device makes that mistake, tell the sd driver.
220 		 */
221 		if (us->fflags & US_FL_FIX_CAPACITY)
222 			sdev->fix_capacity = 1;
223 
224 		/*
225 		 * A few disks have two indistinguishable version, one of
226 		 * which reports the correct capacity and the other does not.
227 		 * The sd driver has to guess which is the case.
228 		 */
229 		if (us->fflags & US_FL_CAPACITY_HEURISTICS)
230 			sdev->guess_capacity = 1;
231 
232 		/* Some devices cannot handle READ_CAPACITY_16 */
233 		if (us->fflags & US_FL_NO_READ_CAPACITY_16)
234 			sdev->no_read_capacity_16 = 1;
235 
236 		/*
237 		 * Many devices do not respond properly to READ_CAPACITY_16.
238 		 * Tell the SCSI layer to try READ_CAPACITY_10 first.
239 		 * However some USB 3.0 drive enclosures return capacity
240 		 * modulo 2TB. Those must use READ_CAPACITY_16
241 		 */
242 		if (!(us->fflags & US_FL_NEEDS_CAP16))
243 			sdev->try_rc_10_first = 1;
244 
245 		/*
246 		 * assume SPC3 or latter devices support sense size > 18
247 		 * unless US_FL_BAD_SENSE quirk is specified.
248 		 */
249 		if (sdev->scsi_level > SCSI_SPC_2 &&
250 		    !(us->fflags & US_FL_BAD_SENSE))
251 			us->fflags |= US_FL_SANE_SENSE;
252 
253 		/*
254 		 * USB-IDE bridges tend to report SK = 0x04 (Non-recoverable
255 		 * Hardware Error) when any low-level error occurs,
256 		 * recoverable or not.  Setting this flag tells the SCSI
257 		 * midlayer to retry such commands, which frequently will
258 		 * succeed and fix the error.  The worst this can lead to
259 		 * is an occasional series of retries that will all fail.
260 		 */
261 		sdev->retry_hwerror = 1;
262 
263 		/*
264 		 * USB disks should allow restart.  Some drives spin down
265 		 * automatically, requiring a START-STOP UNIT command.
266 		 */
267 		sdev->allow_restart = 1;
268 
269 		/*
270 		 * Some USB cardreaders have trouble reading an sdcard's last
271 		 * sector in a larger then 1 sector read, since the performance
272 		 * impact is negligible we set this flag for all USB disks
273 		 */
274 		sdev->last_sector_bug = 1;
275 
276 		/*
277 		 * Enable last-sector hacks for single-target devices using
278 		 * the Bulk-only transport, unless we already know the
279 		 * capacity will be decremented or is correct.
280 		 */
281 		if (!(us->fflags & (US_FL_FIX_CAPACITY | US_FL_CAPACITY_OK |
282 					US_FL_SCM_MULT_TARG)) &&
283 				us->protocol == USB_PR_BULK)
284 			us->use_last_sector_hacks = 1;
285 
286 		/* Check if write cache default on flag is set or not */
287 		if (us->fflags & US_FL_WRITE_CACHE)
288 			sdev->wce_default_on = 1;
289 
290 		/* A few buggy USB-ATA bridges don't understand FUA */
291 		if (us->fflags & US_FL_BROKEN_FUA)
292 			sdev->broken_fua = 1;
293 
294 		/* Some even totally fail to indicate a cache */
295 		if (us->fflags & US_FL_ALWAYS_SYNC) {
296 			/* don't read caching information */
297 			sdev->skip_ms_page_8 = 1;
298 			sdev->skip_ms_page_3f = 1;
299 			/* assume sync is needed */
300 			sdev->wce_default_on = 1;
301 		}
302 	} else {
303 
304 		/*
305 		 * Non-disk-type devices don't need to ignore any pages
306 		 * or to force 192-byte transfer lengths for MODE SENSE.
307 		 * But they do need to use MODE SENSE(10).
308 		 */
309 		sdev->use_10_for_ms = 1;
310 
311 		/* Some (fake) usb cdrom devices don't like READ_DISC_INFO */
312 		if (us->fflags & US_FL_NO_READ_DISC_INFO)
313 			sdev->no_read_disc_info = 1;
314 	}
315 
316 	/*
317 	 * The CB and CBI transports have no way to pass LUN values
318 	 * other than the bits in the second byte of a CDB.  But those
319 	 * bits don't get set to the LUN value if the device reports
320 	 * scsi_level == 0 (UNKNOWN).  Hence such devices must necessarily
321 	 * be single-LUN.
322 	 */
323 	if ((us->protocol == USB_PR_CB || us->protocol == USB_PR_CBI) &&
324 			sdev->scsi_level == SCSI_UNKNOWN)
325 		us->max_lun = 0;
326 
327 	/*
328 	 * Some devices choke when they receive a PREVENT-ALLOW MEDIUM
329 	 * REMOVAL command, so suppress those commands.
330 	 */
331 	if (us->fflags & US_FL_NOT_LOCKABLE)
332 		sdev->lockable = 0;
333 
334 	/*
335 	 * this is to satisfy the compiler, tho I don't think the
336 	 * return code is ever checked anywhere.
337 	 */
338 	return 0;
339 }
340 
target_alloc(struct scsi_target * starget)341 static int target_alloc(struct scsi_target *starget)
342 {
343 	struct us_data *us = host_to_us(dev_to_shost(starget->dev.parent));
344 
345 	/*
346 	 * Some USB drives don't support REPORT LUNS, even though they
347 	 * report a SCSI revision level above 2.  Tell the SCSI layer
348 	 * not to issue that command; it will perform a normal sequential
349 	 * scan instead.
350 	 */
351 	starget->no_report_luns = 1;
352 
353 	/*
354 	 * The UFI spec treats the Peripheral Qualifier bits in an
355 	 * INQUIRY result as reserved and requires devices to set them
356 	 * to 0.  However the SCSI spec requires these bits to be set
357 	 * to 3 to indicate when a LUN is not present.
358 	 *
359 	 * Let the scanning code know if this target merely sets
360 	 * Peripheral Device Type to 0x1f to indicate no LUN.
361 	 */
362 	if (us->subclass == USB_SC_UFI)
363 		starget->pdt_1f_for_no_lun = 1;
364 
365 	return 0;
366 }
367 
368 /* queue a command */
369 /* This is always called with scsi_lock(host) held */
queuecommand_lck(struct scsi_cmnd * srb,void (* done)(struct scsi_cmnd *))370 static int queuecommand_lck(struct scsi_cmnd *srb,
371 			void (*done)(struct scsi_cmnd *))
372 {
373 	struct us_data *us = host_to_us(srb->device->host);
374 
375 	/* check for state-transition errors */
376 	if (us->srb != NULL) {
377 		dev_err(&us->pusb_intf->dev,
378 			"Error in %s: us->srb = %p\n", __func__, us->srb);
379 		return SCSI_MLQUEUE_HOST_BUSY;
380 	}
381 
382 	/* fail the command if we are disconnecting */
383 	if (test_bit(US_FLIDX_DISCONNECTING, &us->dflags)) {
384 		usb_stor_dbg(us, "Fail command during disconnect\n");
385 		srb->result = DID_NO_CONNECT << 16;
386 		done(srb);
387 		return 0;
388 	}
389 
390 	if ((us->fflags & US_FL_NO_ATA_1X) &&
391 			(srb->cmnd[0] == ATA_12 || srb->cmnd[0] == ATA_16)) {
392 		memcpy(srb->sense_buffer, usb_stor_sense_invalidCDB,
393 		       sizeof(usb_stor_sense_invalidCDB));
394 		srb->result = SAM_STAT_CHECK_CONDITION;
395 		done(srb);
396 		return 0;
397 	}
398 
399 	/* enqueue the command and wake up the control thread */
400 	srb->scsi_done = done;
401 	us->srb = srb;
402 	complete(&us->cmnd_ready);
403 
404 	return 0;
405 }
406 
DEF_SCSI_QCMD(queuecommand)407 static DEF_SCSI_QCMD(queuecommand)
408 
409 /***********************************************************************
410  * Error handling functions
411  ***********************************************************************/
412 
413 /* Command timeout and abort */
414 static int command_abort(struct scsi_cmnd *srb)
415 {
416 	struct us_data *us = host_to_us(srb->device->host);
417 
418 	usb_stor_dbg(us, "%s called\n", __func__);
419 
420 	/*
421 	 * us->srb together with the TIMED_OUT, RESETTING, and ABORTING
422 	 * bits are protected by the host lock.
423 	 */
424 	scsi_lock(us_to_host(us));
425 
426 	/* Is this command still active? */
427 	if (us->srb != srb) {
428 		scsi_unlock(us_to_host(us));
429 		usb_stor_dbg(us, "-- nothing to abort\n");
430 		return FAILED;
431 	}
432 
433 	/*
434 	 * Set the TIMED_OUT bit.  Also set the ABORTING bit, but only if
435 	 * a device reset isn't already in progress (to avoid interfering
436 	 * with the reset).  Note that we must retain the host lock while
437 	 * calling usb_stor_stop_transport(); otherwise it might interfere
438 	 * with an auto-reset that begins as soon as we release the lock.
439 	 */
440 	set_bit(US_FLIDX_TIMED_OUT, &us->dflags);
441 	if (!test_bit(US_FLIDX_RESETTING, &us->dflags)) {
442 		set_bit(US_FLIDX_ABORTING, &us->dflags);
443 		usb_stor_stop_transport(us);
444 	}
445 	scsi_unlock(us_to_host(us));
446 
447 	/* Wait for the aborted command to finish */
448 	wait_for_completion(&us->notify);
449 	return SUCCESS;
450 }
451 
452 /*
453  * This invokes the transport reset mechanism to reset the state of the
454  * device
455  */
device_reset(struct scsi_cmnd * srb)456 static int device_reset(struct scsi_cmnd *srb)
457 {
458 	struct us_data *us = host_to_us(srb->device->host);
459 	int result;
460 
461 	usb_stor_dbg(us, "%s called\n", __func__);
462 
463 	/* lock the device pointers and do the reset */
464 	mutex_lock(&(us->dev_mutex));
465 	result = us->transport_reset(us);
466 	mutex_unlock(&us->dev_mutex);
467 
468 	return result < 0 ? FAILED : SUCCESS;
469 }
470 
471 /* Simulate a SCSI bus reset by resetting the device's USB port. */
bus_reset(struct scsi_cmnd * srb)472 static int bus_reset(struct scsi_cmnd *srb)
473 {
474 	struct us_data *us = host_to_us(srb->device->host);
475 	int result;
476 
477 	usb_stor_dbg(us, "%s called\n", __func__);
478 
479 	result = usb_stor_port_reset(us);
480 	return result < 0 ? FAILED : SUCCESS;
481 }
482 
483 /*
484  * Report a driver-initiated device reset to the SCSI layer.
485  * Calling this for a SCSI-initiated reset is unnecessary but harmless.
486  * The caller must own the SCSI host lock.
487  */
usb_stor_report_device_reset(struct us_data * us)488 void usb_stor_report_device_reset(struct us_data *us)
489 {
490 	int i;
491 	struct Scsi_Host *host = us_to_host(us);
492 
493 	scsi_report_device_reset(host, 0, 0);
494 	if (us->fflags & US_FL_SCM_MULT_TARG) {
495 		for (i = 1; i < host->max_id; ++i)
496 			scsi_report_device_reset(host, 0, i);
497 	}
498 }
499 
500 /*
501  * Report a driver-initiated bus reset to the SCSI layer.
502  * Calling this for a SCSI-initiated reset is unnecessary but harmless.
503  * The caller must not own the SCSI host lock.
504  */
usb_stor_report_bus_reset(struct us_data * us)505 void usb_stor_report_bus_reset(struct us_data *us)
506 {
507 	struct Scsi_Host *host = us_to_host(us);
508 
509 	scsi_lock(host);
510 	scsi_report_bus_reset(host, 0);
511 	scsi_unlock(host);
512 }
513 
514 /***********************************************************************
515  * /proc/scsi/ functions
516  ***********************************************************************/
517 
write_info(struct Scsi_Host * host,char * buffer,int length)518 static int write_info(struct Scsi_Host *host, char *buffer, int length)
519 {
520 	/* if someone is sending us data, just throw it away */
521 	return length;
522 }
523 
show_info(struct seq_file * m,struct Scsi_Host * host)524 static int show_info (struct seq_file *m, struct Scsi_Host *host)
525 {
526 	struct us_data *us = host_to_us(host);
527 	const char *string;
528 
529 	/* print the controller name */
530 	seq_printf(m, "   Host scsi%d: usb-storage\n", host->host_no);
531 
532 	/* print product, vendor, and serial number strings */
533 	if (us->pusb_dev->manufacturer)
534 		string = us->pusb_dev->manufacturer;
535 	else if (us->unusual_dev->vendorName)
536 		string = us->unusual_dev->vendorName;
537 	else
538 		string = "Unknown";
539 	seq_printf(m, "       Vendor: %s\n", string);
540 	if (us->pusb_dev->product)
541 		string = us->pusb_dev->product;
542 	else if (us->unusual_dev->productName)
543 		string = us->unusual_dev->productName;
544 	else
545 		string = "Unknown";
546 	seq_printf(m, "      Product: %s\n", string);
547 	if (us->pusb_dev->serial)
548 		string = us->pusb_dev->serial;
549 	else
550 		string = "None";
551 	seq_printf(m, "Serial Number: %s\n", string);
552 
553 	/* show the protocol and transport */
554 	seq_printf(m, "     Protocol: %s\n", us->protocol_name);
555 	seq_printf(m, "    Transport: %s\n", us->transport_name);
556 
557 	/* show the device flags */
558 	seq_printf(m, "       Quirks:");
559 
560 #define US_FLAG(name, value) \
561 	if (us->fflags & value) seq_printf(m, " " #name);
562 US_DO_ALL_FLAGS
563 #undef US_FLAG
564 	seq_putc(m, '\n');
565 	return 0;
566 }
567 
568 /***********************************************************************
569  * Sysfs interface
570  ***********************************************************************/
571 
572 /* Output routine for the sysfs max_sectors file */
max_sectors_show(struct device * dev,struct device_attribute * attr,char * buf)573 static ssize_t max_sectors_show(struct device *dev, struct device_attribute *attr, char *buf)
574 {
575 	struct scsi_device *sdev = to_scsi_device(dev);
576 
577 	return sprintf(buf, "%u\n", queue_max_hw_sectors(sdev->request_queue));
578 }
579 
580 /* Input routine for the sysfs max_sectors file */
max_sectors_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)581 static ssize_t max_sectors_store(struct device *dev, struct device_attribute *attr, const char *buf,
582 		size_t count)
583 {
584 	struct scsi_device *sdev = to_scsi_device(dev);
585 	unsigned short ms;
586 
587 	if (sscanf(buf, "%hu", &ms) > 0) {
588 		blk_queue_max_hw_sectors(sdev->request_queue, ms);
589 		return count;
590 	}
591 	return -EINVAL;
592 }
593 static DEVICE_ATTR_RW(max_sectors);
594 
595 static struct device_attribute *sysfs_device_attr_list[] = {
596 	&dev_attr_max_sectors,
597 	NULL,
598 };
599 
600 /*
601  * this defines our host template, with which we'll allocate hosts
602  */
603 
604 static const struct scsi_host_template usb_stor_host_template = {
605 	/* basic userland interface stuff */
606 	.name =				"usb-storage",
607 	.proc_name =			"usb-storage",
608 	.show_info =			show_info,
609 	.write_info =			write_info,
610 	.info =				host_info,
611 
612 	/* command interface -- queued only */
613 	.queuecommand =			queuecommand,
614 
615 	/* error and abort handlers */
616 	.eh_abort_handler =		command_abort,
617 	.eh_device_reset_handler =	device_reset,
618 	.eh_bus_reset_handler =		bus_reset,
619 
620 	/* queue commands only, only one command per LUN */
621 	.can_queue =			1,
622 
623 	/* unknown initiator id */
624 	.this_id =			-1,
625 
626 	.slave_alloc =			slave_alloc,
627 	.slave_configure =		slave_configure,
628 	.target_alloc =			target_alloc,
629 
630 	/* lots of sg segments can be handled */
631 	.sg_tablesize =			SG_MAX_SEGMENTS,
632 
633 
634 	/*
635 	 * Limit the total size of a transfer to 120 KB.
636 	 *
637 	 * Some devices are known to choke with anything larger. It seems like
638 	 * the problem stems from the fact that original IDE controllers had
639 	 * only an 8-bit register to hold the number of sectors in one transfer
640 	 * and even those couldn't handle a full 256 sectors.
641 	 *
642 	 * Because we want to make sure we interoperate with as many devices as
643 	 * possible, we will maintain a 240 sector transfer size limit for USB
644 	 * Mass Storage devices.
645 	 *
646 	 * Tests show that other operating have similar limits with Microsoft
647 	 * Windows 7 limiting transfers to 128 sectors for both USB2 and USB3
648 	 * and Apple Mac OS X 10.11 limiting transfers to 256 sectors for USB2
649 	 * and 2048 for USB3 devices.
650 	 */
651 	.max_sectors =                  240,
652 
653 	/* emulated HBA */
654 	.emulated =			1,
655 
656 	/* we do our own delay after a device or bus reset */
657 	.skip_settle_delay =		1,
658 
659 	/* sysfs device attributes */
660 	.sdev_attrs =			sysfs_device_attr_list,
661 
662 	/* module management */
663 	.module =			THIS_MODULE
664 };
665 
usb_stor_host_template_init(struct scsi_host_template * sht,const char * name,struct module * owner)666 void usb_stor_host_template_init(struct scsi_host_template *sht,
667 				 const char *name, struct module *owner)
668 {
669 	*sht = usb_stor_host_template;
670 	sht->name = name;
671 	sht->proc_name = name;
672 	sht->module = owner;
673 }
674 EXPORT_SYMBOL_GPL(usb_stor_host_template_init);
675 
676 /* To Report "Illegal Request: Invalid Field in CDB */
677 unsigned char usb_stor_sense_invalidCDB[18] = {
678 	[0]	= 0x70,			    /* current error */
679 	[2]	= ILLEGAL_REQUEST,	    /* Illegal Request = 0x05 */
680 	[7]	= 0x0a,			    /* additional length */
681 	[12]	= 0x24			    /* Invalid Field in CDB */
682 };
683 EXPORT_SYMBOL_GPL(usb_stor_sense_invalidCDB);
684