xref: /openbmc/linux/drivers/usb/storage/uas.c (revision df2634f43f5106947f3735a0b61a6527a4b278cd)
1 /*
2  * USB Attached SCSI
3  * Note that this is not the same as the USB Mass Storage driver
4  *
5  * Copyright Matthew Wilcox for Intel Corp, 2010
6  * Copyright Sarah Sharp for Intel Corp, 2010
7  *
8  * Distributed under the terms of the GNU GPL, version two.
9  */
10 
11 #include <linux/blkdev.h>
12 #include <linux/slab.h>
13 #include <linux/types.h>
14 #include <linux/usb.h>
15 #include <linux/usb/storage.h>
16 
17 #include <scsi/scsi.h>
18 #include <scsi/scsi_dbg.h>
19 #include <scsi/scsi_cmnd.h>
20 #include <scsi/scsi_device.h>
21 #include <scsi/scsi_host.h>
22 #include <scsi/scsi_tcq.h>
23 
24 /* Common header for all IUs */
25 struct iu {
26 	__u8 iu_id;
27 	__u8 rsvd1;
28 	__be16 tag;
29 };
30 
31 enum {
32 	IU_ID_COMMAND		= 0x01,
33 	IU_ID_STATUS		= 0x03,
34 	IU_ID_RESPONSE		= 0x04,
35 	IU_ID_TASK_MGMT		= 0x05,
36 	IU_ID_READ_READY	= 0x06,
37 	IU_ID_WRITE_READY	= 0x07,
38 };
39 
40 struct command_iu {
41 	__u8 iu_id;
42 	__u8 rsvd1;
43 	__be16 tag;
44 	__u8 prio_attr;
45 	__u8 rsvd5;
46 	__u8 len;
47 	__u8 rsvd7;
48 	struct scsi_lun lun;
49 	__u8 cdb[16];	/* XXX: Overflow-checking tools may misunderstand */
50 };
51 
52 /*
53  * Also used for the Read Ready and Write Ready IUs since they have the
54  * same first four bytes
55  */
56 struct sense_iu {
57 	__u8 iu_id;
58 	__u8 rsvd1;
59 	__be16 tag;
60 	__be16 status_qual;
61 	__u8 status;
62 	__u8 rsvd7[7];
63 	__be16 len;
64 	__u8 sense[SCSI_SENSE_BUFFERSIZE];
65 };
66 
67 /*
68  * The r00-r01c specs define this version of the SENSE IU data structure.
69  * It's still in use by several different firmware releases.
70  */
71 struct sense_iu_old {
72 	__u8 iu_id;
73 	__u8 rsvd1;
74 	__be16 tag;
75 	__be16 len;
76 	__u8 status;
77 	__u8 service_response;
78 	__u8 sense[SCSI_SENSE_BUFFERSIZE];
79 };
80 
81 enum {
82 	CMD_PIPE_ID		= 1,
83 	STATUS_PIPE_ID		= 2,
84 	DATA_IN_PIPE_ID		= 3,
85 	DATA_OUT_PIPE_ID	= 4,
86 
87 	UAS_SIMPLE_TAG		= 0,
88 	UAS_HEAD_TAG		= 1,
89 	UAS_ORDERED_TAG		= 2,
90 	UAS_ACA			= 4,
91 };
92 
93 struct uas_dev_info {
94 	struct usb_interface *intf;
95 	struct usb_device *udev;
96 	int qdepth;
97 	unsigned cmd_pipe, status_pipe, data_in_pipe, data_out_pipe;
98 	unsigned use_streams:1;
99 	unsigned uas_sense_old:1;
100 };
101 
102 enum {
103 	ALLOC_STATUS_URB	= (1 << 0),
104 	SUBMIT_STATUS_URB	= (1 << 1),
105 	ALLOC_DATA_IN_URB	= (1 << 2),
106 	SUBMIT_DATA_IN_URB	= (1 << 3),
107 	ALLOC_DATA_OUT_URB	= (1 << 4),
108 	SUBMIT_DATA_OUT_URB	= (1 << 5),
109 	ALLOC_CMD_URB		= (1 << 6),
110 	SUBMIT_CMD_URB		= (1 << 7),
111 };
112 
113 /* Overrides scsi_pointer */
114 struct uas_cmd_info {
115 	unsigned int state;
116 	unsigned int stream;
117 	struct urb *cmd_urb;
118 	struct urb *status_urb;
119 	struct urb *data_in_urb;
120 	struct urb *data_out_urb;
121 	struct list_head list;
122 };
123 
124 /* I hate forward declarations, but I actually have a loop */
125 static int uas_submit_urbs(struct scsi_cmnd *cmnd,
126 				struct uas_dev_info *devinfo, gfp_t gfp);
127 
128 static DEFINE_SPINLOCK(uas_work_lock);
129 static LIST_HEAD(uas_work_list);
130 
131 static void uas_do_work(struct work_struct *work)
132 {
133 	struct uas_cmd_info *cmdinfo;
134 	struct list_head list;
135 
136 	spin_lock_irq(&uas_work_lock);
137 	list_replace_init(&uas_work_list, &list);
138 	spin_unlock_irq(&uas_work_lock);
139 
140 	list_for_each_entry(cmdinfo, &list, list) {
141 		struct scsi_pointer *scp = (void *)cmdinfo;
142 		struct scsi_cmnd *cmnd = container_of(scp,
143 							struct scsi_cmnd, SCp);
144 		uas_submit_urbs(cmnd, cmnd->device->hostdata, GFP_NOIO);
145 	}
146 }
147 
148 static DECLARE_WORK(uas_work, uas_do_work);
149 
150 static void uas_sense(struct urb *urb, struct scsi_cmnd *cmnd)
151 {
152 	struct sense_iu *sense_iu = urb->transfer_buffer;
153 	struct scsi_device *sdev = cmnd->device;
154 
155 	if (urb->actual_length > 16) {
156 		unsigned len = be16_to_cpup(&sense_iu->len);
157 		if (len + 16 != urb->actual_length) {
158 			int newlen = min(len + 16, urb->actual_length) - 16;
159 			if (newlen < 0)
160 				newlen = 0;
161 			sdev_printk(KERN_INFO, sdev, "%s: urb length %d "
162 				"disagrees with IU sense data length %d, "
163 				"using %d bytes of sense data\n", __func__,
164 					urb->actual_length, len, newlen);
165 			len = newlen;
166 		}
167 		memcpy(cmnd->sense_buffer, sense_iu->sense, len);
168 	}
169 
170 	cmnd->result = sense_iu->status;
171 	if (sdev->current_cmnd)
172 		sdev->current_cmnd = NULL;
173 	cmnd->scsi_done(cmnd);
174 	usb_free_urb(urb);
175 }
176 
177 static void uas_sense_old(struct urb *urb, struct scsi_cmnd *cmnd)
178 {
179 	struct sense_iu_old *sense_iu = urb->transfer_buffer;
180 	struct scsi_device *sdev = cmnd->device;
181 
182 	if (urb->actual_length > 8) {
183 		unsigned len = be16_to_cpup(&sense_iu->len) - 2;
184 		if (len + 8 != urb->actual_length) {
185 			int newlen = min(len + 8, urb->actual_length) - 8;
186 			if (newlen < 0)
187 				newlen = 0;
188 			sdev_printk(KERN_INFO, sdev, "%s: urb length %d "
189 				"disagrees with IU sense data length %d, "
190 				"using %d bytes of sense data\n", __func__,
191 					urb->actual_length, len, newlen);
192 			len = newlen;
193 		}
194 		memcpy(cmnd->sense_buffer, sense_iu->sense, len);
195 	}
196 
197 	cmnd->result = sense_iu->status;
198 	if (sdev->current_cmnd)
199 		sdev->current_cmnd = NULL;
200 	cmnd->scsi_done(cmnd);
201 	usb_free_urb(urb);
202 }
203 
204 static void uas_xfer_data(struct urb *urb, struct scsi_cmnd *cmnd,
205 							unsigned direction)
206 {
207 	struct uas_cmd_info *cmdinfo = (void *)&cmnd->SCp;
208 	int err;
209 
210 	cmdinfo->state = direction | SUBMIT_STATUS_URB;
211 	err = uas_submit_urbs(cmnd, cmnd->device->hostdata, GFP_ATOMIC);
212 	if (err) {
213 		spin_lock(&uas_work_lock);
214 		list_add_tail(&cmdinfo->list, &uas_work_list);
215 		spin_unlock(&uas_work_lock);
216 		schedule_work(&uas_work);
217 	}
218 }
219 
220 static void uas_stat_cmplt(struct urb *urb)
221 {
222 	struct iu *iu = urb->transfer_buffer;
223 	struct scsi_device *sdev = urb->context;
224 	struct uas_dev_info *devinfo = sdev->hostdata;
225 	struct scsi_cmnd *cmnd;
226 	u16 tag;
227 
228 	if (urb->status) {
229 		dev_err(&urb->dev->dev, "URB BAD STATUS %d\n", urb->status);
230 		usb_free_urb(urb);
231 		return;
232 	}
233 
234 	tag = be16_to_cpup(&iu->tag) - 1;
235 	if (sdev->current_cmnd)
236 		cmnd = sdev->current_cmnd;
237 	else
238 		cmnd = scsi_find_tag(sdev, tag);
239 	if (!cmnd)
240 		return;
241 
242 	switch (iu->iu_id) {
243 	case IU_ID_STATUS:
244 		if (urb->actual_length < 16)
245 			devinfo->uas_sense_old = 1;
246 		if (devinfo->uas_sense_old)
247 			uas_sense_old(urb, cmnd);
248 		else
249 			uas_sense(urb, cmnd);
250 		break;
251 	case IU_ID_READ_READY:
252 		uas_xfer_data(urb, cmnd, SUBMIT_DATA_IN_URB);
253 		break;
254 	case IU_ID_WRITE_READY:
255 		uas_xfer_data(urb, cmnd, SUBMIT_DATA_OUT_URB);
256 		break;
257 	default:
258 		scmd_printk(KERN_ERR, cmnd,
259 			"Bogus IU (%d) received on status pipe\n", iu->iu_id);
260 	}
261 }
262 
263 static void uas_data_cmplt(struct urb *urb)
264 {
265 	struct scsi_data_buffer *sdb = urb->context;
266 	sdb->resid = sdb->length - urb->actual_length;
267 	usb_free_urb(urb);
268 }
269 
270 static struct urb *uas_alloc_data_urb(struct uas_dev_info *devinfo, gfp_t gfp,
271 				unsigned int pipe, u16 stream_id,
272 				struct scsi_data_buffer *sdb,
273 				enum dma_data_direction dir)
274 {
275 	struct usb_device *udev = devinfo->udev;
276 	struct urb *urb = usb_alloc_urb(0, gfp);
277 
278 	if (!urb)
279 		goto out;
280 	usb_fill_bulk_urb(urb, udev, pipe, NULL, sdb->length, uas_data_cmplt,
281 									sdb);
282 	if (devinfo->use_streams)
283 		urb->stream_id = stream_id;
284 	urb->num_sgs = udev->bus->sg_tablesize ? sdb->table.nents : 0;
285 	urb->sg = sdb->table.sgl;
286  out:
287 	return urb;
288 }
289 
290 static struct urb *uas_alloc_sense_urb(struct uas_dev_info *devinfo, gfp_t gfp,
291 					struct scsi_cmnd *cmnd, u16 stream_id)
292 {
293 	struct usb_device *udev = devinfo->udev;
294 	struct urb *urb = usb_alloc_urb(0, gfp);
295 	struct sense_iu *iu;
296 
297 	if (!urb)
298 		goto out;
299 
300 	iu = kzalloc(sizeof(*iu), gfp);
301 	if (!iu)
302 		goto free;
303 
304 	usb_fill_bulk_urb(urb, udev, devinfo->status_pipe, iu, sizeof(*iu),
305 						uas_stat_cmplt, cmnd->device);
306 	urb->stream_id = stream_id;
307 	urb->transfer_flags |= URB_FREE_BUFFER;
308  out:
309 	return urb;
310  free:
311 	usb_free_urb(urb);
312 	return NULL;
313 }
314 
315 static struct urb *uas_alloc_cmd_urb(struct uas_dev_info *devinfo, gfp_t gfp,
316 					struct scsi_cmnd *cmnd, u16 stream_id)
317 {
318 	struct usb_device *udev = devinfo->udev;
319 	struct scsi_device *sdev = cmnd->device;
320 	struct urb *urb = usb_alloc_urb(0, gfp);
321 	struct command_iu *iu;
322 	int len;
323 
324 	if (!urb)
325 		goto out;
326 
327 	len = cmnd->cmd_len - 16;
328 	if (len < 0)
329 		len = 0;
330 	len = ALIGN(len, 4);
331 	iu = kzalloc(sizeof(*iu) + len, gfp);
332 	if (!iu)
333 		goto free;
334 
335 	iu->iu_id = IU_ID_COMMAND;
336 	iu->tag = cpu_to_be16(stream_id);
337 	iu->prio_attr = UAS_SIMPLE_TAG;
338 	iu->len = len;
339 	int_to_scsilun(sdev->lun, &iu->lun);
340 	memcpy(iu->cdb, cmnd->cmnd, cmnd->cmd_len);
341 
342 	usb_fill_bulk_urb(urb, udev, devinfo->cmd_pipe, iu, sizeof(*iu) + len,
343 							usb_free_urb, NULL);
344 	urb->transfer_flags |= URB_FREE_BUFFER;
345  out:
346 	return urb;
347  free:
348 	usb_free_urb(urb);
349 	return NULL;
350 }
351 
352 /*
353  * Why should I request the Status IU before sending the Command IU?  Spec
354  * says to, but also says the device may receive them in any order.  Seems
355  * daft to me.
356  */
357 
358 static int uas_submit_urbs(struct scsi_cmnd *cmnd,
359 					struct uas_dev_info *devinfo, gfp_t gfp)
360 {
361 	struct uas_cmd_info *cmdinfo = (void *)&cmnd->SCp;
362 
363 	if (cmdinfo->state & ALLOC_STATUS_URB) {
364 		cmdinfo->status_urb = uas_alloc_sense_urb(devinfo, gfp, cmnd,
365 							  cmdinfo->stream);
366 		if (!cmdinfo->status_urb)
367 			return SCSI_MLQUEUE_DEVICE_BUSY;
368 		cmdinfo->state &= ~ALLOC_STATUS_URB;
369 	}
370 
371 	if (cmdinfo->state & SUBMIT_STATUS_URB) {
372 		if (usb_submit_urb(cmdinfo->status_urb, gfp)) {
373 			scmd_printk(KERN_INFO, cmnd,
374 					"sense urb submission failure\n");
375 			return SCSI_MLQUEUE_DEVICE_BUSY;
376 		}
377 		cmdinfo->state &= ~SUBMIT_STATUS_URB;
378 	}
379 
380 	if (cmdinfo->state & ALLOC_DATA_IN_URB) {
381 		cmdinfo->data_in_urb = uas_alloc_data_urb(devinfo, gfp,
382 					devinfo->data_in_pipe, cmdinfo->stream,
383 					scsi_in(cmnd), DMA_FROM_DEVICE);
384 		if (!cmdinfo->data_in_urb)
385 			return SCSI_MLQUEUE_DEVICE_BUSY;
386 		cmdinfo->state &= ~ALLOC_DATA_IN_URB;
387 	}
388 
389 	if (cmdinfo->state & SUBMIT_DATA_IN_URB) {
390 		if (usb_submit_urb(cmdinfo->data_in_urb, gfp)) {
391 			scmd_printk(KERN_INFO, cmnd,
392 					"data in urb submission failure\n");
393 			return SCSI_MLQUEUE_DEVICE_BUSY;
394 		}
395 		cmdinfo->state &= ~SUBMIT_DATA_IN_URB;
396 	}
397 
398 	if (cmdinfo->state & ALLOC_DATA_OUT_URB) {
399 		cmdinfo->data_out_urb = uas_alloc_data_urb(devinfo, gfp,
400 					devinfo->data_out_pipe, cmdinfo->stream,
401 					scsi_out(cmnd), DMA_TO_DEVICE);
402 		if (!cmdinfo->data_out_urb)
403 			return SCSI_MLQUEUE_DEVICE_BUSY;
404 		cmdinfo->state &= ~ALLOC_DATA_OUT_URB;
405 	}
406 
407 	if (cmdinfo->state & SUBMIT_DATA_OUT_URB) {
408 		if (usb_submit_urb(cmdinfo->data_out_urb, gfp)) {
409 			scmd_printk(KERN_INFO, cmnd,
410 					"data out urb submission failure\n");
411 			return SCSI_MLQUEUE_DEVICE_BUSY;
412 		}
413 		cmdinfo->state &= ~SUBMIT_DATA_OUT_URB;
414 	}
415 
416 	if (cmdinfo->state & ALLOC_CMD_URB) {
417 		cmdinfo->cmd_urb = uas_alloc_cmd_urb(devinfo, gfp, cmnd,
418 							cmdinfo->stream);
419 		if (!cmdinfo->cmd_urb)
420 			return SCSI_MLQUEUE_DEVICE_BUSY;
421 		cmdinfo->state &= ~ALLOC_CMD_URB;
422 	}
423 
424 	if (cmdinfo->state & SUBMIT_CMD_URB) {
425 		if (usb_submit_urb(cmdinfo->cmd_urb, gfp)) {
426 			scmd_printk(KERN_INFO, cmnd,
427 					"cmd urb submission failure\n");
428 			return SCSI_MLQUEUE_DEVICE_BUSY;
429 		}
430 		cmdinfo->state &= ~SUBMIT_CMD_URB;
431 	}
432 
433 	return 0;
434 }
435 
436 static int uas_queuecommand_lck(struct scsi_cmnd *cmnd,
437 					void (*done)(struct scsi_cmnd *))
438 {
439 	struct scsi_device *sdev = cmnd->device;
440 	struct uas_dev_info *devinfo = sdev->hostdata;
441 	struct uas_cmd_info *cmdinfo = (void *)&cmnd->SCp;
442 	int err;
443 
444 	BUILD_BUG_ON(sizeof(struct uas_cmd_info) > sizeof(struct scsi_pointer));
445 
446 	if (!cmdinfo->status_urb && sdev->current_cmnd)
447 		return SCSI_MLQUEUE_DEVICE_BUSY;
448 
449 	if (blk_rq_tagged(cmnd->request)) {
450 		cmdinfo->stream = cmnd->request->tag + 1;
451 	} else {
452 		sdev->current_cmnd = cmnd;
453 		cmdinfo->stream = 1;
454 	}
455 
456 	cmnd->scsi_done = done;
457 
458 	cmdinfo->state = ALLOC_STATUS_URB | SUBMIT_STATUS_URB |
459 			ALLOC_CMD_URB | SUBMIT_CMD_URB;
460 
461 	switch (cmnd->sc_data_direction) {
462 	case DMA_FROM_DEVICE:
463 		cmdinfo->state |= ALLOC_DATA_IN_URB | SUBMIT_DATA_IN_URB;
464 		break;
465 	case DMA_BIDIRECTIONAL:
466 		cmdinfo->state |= ALLOC_DATA_IN_URB | SUBMIT_DATA_IN_URB;
467 	case DMA_TO_DEVICE:
468 		cmdinfo->state |= ALLOC_DATA_OUT_URB | SUBMIT_DATA_OUT_URB;
469 	case DMA_NONE:
470 		break;
471 	}
472 
473 	if (!devinfo->use_streams) {
474 		cmdinfo->state &= ~(SUBMIT_DATA_IN_URB | SUBMIT_DATA_OUT_URB);
475 		cmdinfo->stream = 0;
476 	}
477 
478 	err = uas_submit_urbs(cmnd, devinfo, GFP_ATOMIC);
479 	if (err) {
480 		/* If we did nothing, give up now */
481 		if (cmdinfo->state & SUBMIT_STATUS_URB) {
482 			usb_free_urb(cmdinfo->status_urb);
483 			return SCSI_MLQUEUE_DEVICE_BUSY;
484 		}
485 		spin_lock(&uas_work_lock);
486 		list_add_tail(&cmdinfo->list, &uas_work_list);
487 		spin_unlock(&uas_work_lock);
488 		schedule_work(&uas_work);
489 	}
490 
491 	return 0;
492 }
493 
494 static DEF_SCSI_QCMD(uas_queuecommand)
495 
496 static int uas_eh_abort_handler(struct scsi_cmnd *cmnd)
497 {
498 	struct scsi_device *sdev = cmnd->device;
499 	sdev_printk(KERN_INFO, sdev, "%s tag %d\n", __func__,
500 							cmnd->request->tag);
501 
502 /* XXX: Send ABORT TASK Task Management command */
503 	return FAILED;
504 }
505 
506 static int uas_eh_device_reset_handler(struct scsi_cmnd *cmnd)
507 {
508 	struct scsi_device *sdev = cmnd->device;
509 	sdev_printk(KERN_INFO, sdev, "%s tag %d\n", __func__,
510 							cmnd->request->tag);
511 
512 /* XXX: Send LOGICAL UNIT RESET Task Management command */
513 	return FAILED;
514 }
515 
516 static int uas_eh_target_reset_handler(struct scsi_cmnd *cmnd)
517 {
518 	struct scsi_device *sdev = cmnd->device;
519 	sdev_printk(KERN_INFO, sdev, "%s tag %d\n", __func__,
520 							cmnd->request->tag);
521 
522 /* XXX: Can we reset just the one USB interface?
523  * Would calling usb_set_interface() have the right effect?
524  */
525 	return FAILED;
526 }
527 
528 static int uas_eh_bus_reset_handler(struct scsi_cmnd *cmnd)
529 {
530 	struct scsi_device *sdev = cmnd->device;
531 	struct uas_dev_info *devinfo = sdev->hostdata;
532 	struct usb_device *udev = devinfo->udev;
533 
534 	sdev_printk(KERN_INFO, sdev, "%s tag %d\n", __func__,
535 							cmnd->request->tag);
536 
537 	if (usb_reset_device(udev))
538 		return SUCCESS;
539 
540 	return FAILED;
541 }
542 
543 static int uas_slave_alloc(struct scsi_device *sdev)
544 {
545 	sdev->hostdata = (void *)sdev->host->hostdata[0];
546 	return 0;
547 }
548 
549 static int uas_slave_configure(struct scsi_device *sdev)
550 {
551 	struct uas_dev_info *devinfo = sdev->hostdata;
552 	scsi_set_tag_type(sdev, MSG_ORDERED_TAG);
553 	scsi_activate_tcq(sdev, devinfo->qdepth - 1);
554 	return 0;
555 }
556 
557 static struct scsi_host_template uas_host_template = {
558 	.module = THIS_MODULE,
559 	.name = "uas",
560 	.queuecommand = uas_queuecommand,
561 	.slave_alloc = uas_slave_alloc,
562 	.slave_configure = uas_slave_configure,
563 	.eh_abort_handler = uas_eh_abort_handler,
564 	.eh_device_reset_handler = uas_eh_device_reset_handler,
565 	.eh_target_reset_handler = uas_eh_target_reset_handler,
566 	.eh_bus_reset_handler = uas_eh_bus_reset_handler,
567 	.can_queue = 65536,	/* Is there a limit on the _host_ ? */
568 	.this_id = -1,
569 	.sg_tablesize = SG_NONE,
570 	.cmd_per_lun = 1,	/* until we override it */
571 	.skip_settle_delay = 1,
572 	.ordered_tag = 1,
573 };
574 
575 static struct usb_device_id uas_usb_ids[] = {
576 	{ USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, USB_SC_SCSI, USB_PR_BULK) },
577 	{ USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, USB_SC_SCSI, USB_PR_UAS) },
578 	/* 0xaa is a prototype device I happen to have access to */
579 	{ USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, USB_SC_SCSI, 0xaa) },
580 	{ }
581 };
582 MODULE_DEVICE_TABLE(usb, uas_usb_ids);
583 
584 static int uas_is_interface(struct usb_host_interface *intf)
585 {
586 	return (intf->desc.bInterfaceClass == USB_CLASS_MASS_STORAGE &&
587 		intf->desc.bInterfaceSubClass == USB_SC_SCSI &&
588 		intf->desc.bInterfaceProtocol == USB_PR_UAS);
589 }
590 
591 static int uas_switch_interface(struct usb_device *udev,
592 						struct usb_interface *intf)
593 {
594 	int i;
595 
596 	if (uas_is_interface(intf->cur_altsetting))
597 		return 0;
598 
599 	for (i = 0; i < intf->num_altsetting; i++) {
600 		struct usb_host_interface *alt = &intf->altsetting[i];
601 		if (alt == intf->cur_altsetting)
602 			continue;
603 		if (uas_is_interface(alt))
604 			return usb_set_interface(udev,
605 						alt->desc.bInterfaceNumber,
606 						alt->desc.bAlternateSetting);
607 	}
608 
609 	return -ENODEV;
610 }
611 
612 static void uas_configure_endpoints(struct uas_dev_info *devinfo)
613 {
614 	struct usb_host_endpoint *eps[4] = { };
615 	struct usb_interface *intf = devinfo->intf;
616 	struct usb_device *udev = devinfo->udev;
617 	struct usb_host_endpoint *endpoint = intf->cur_altsetting->endpoint;
618 	unsigned i, n_endpoints = intf->cur_altsetting->desc.bNumEndpoints;
619 
620 	devinfo->uas_sense_old = 0;
621 
622 	for (i = 0; i < n_endpoints; i++) {
623 		unsigned char *extra = endpoint[i].extra;
624 		int len = endpoint[i].extralen;
625 		while (len > 1) {
626 			if (extra[1] == USB_DT_PIPE_USAGE) {
627 				unsigned pipe_id = extra[2];
628 				if (pipe_id > 0 && pipe_id < 5)
629 					eps[pipe_id - 1] = &endpoint[i];
630 				break;
631 			}
632 			len -= extra[0];
633 			extra += extra[0];
634 		}
635 	}
636 
637 	/*
638 	 * Assume that if we didn't find a control pipe descriptor, we're
639 	 * using a device with old firmware that happens to be set up like
640 	 * this.
641 	 */
642 	if (!eps[0]) {
643 		devinfo->cmd_pipe = usb_sndbulkpipe(udev, 1);
644 		devinfo->status_pipe = usb_rcvbulkpipe(udev, 1);
645 		devinfo->data_in_pipe = usb_rcvbulkpipe(udev, 2);
646 		devinfo->data_out_pipe = usb_sndbulkpipe(udev, 2);
647 
648 		eps[1] = usb_pipe_endpoint(udev, devinfo->status_pipe);
649 		eps[2] = usb_pipe_endpoint(udev, devinfo->data_in_pipe);
650 		eps[3] = usb_pipe_endpoint(udev, devinfo->data_out_pipe);
651 	} else {
652 		devinfo->cmd_pipe = usb_sndbulkpipe(udev,
653 						eps[0]->desc.bEndpointAddress);
654 		devinfo->status_pipe = usb_rcvbulkpipe(udev,
655 						eps[1]->desc.bEndpointAddress);
656 		devinfo->data_in_pipe = usb_rcvbulkpipe(udev,
657 						eps[2]->desc.bEndpointAddress);
658 		devinfo->data_out_pipe = usb_sndbulkpipe(udev,
659 						eps[3]->desc.bEndpointAddress);
660 	}
661 
662 	devinfo->qdepth = usb_alloc_streams(devinfo->intf, eps + 1, 3, 256,
663 								GFP_KERNEL);
664 	if (devinfo->qdepth < 0) {
665 		devinfo->qdepth = 256;
666 		devinfo->use_streams = 0;
667 	} else {
668 		devinfo->use_streams = 1;
669 	}
670 }
671 
672 /*
673  * XXX: What I'd like to do here is register a SCSI host for each USB host in
674  * the system.  Follow usb-storage's design of registering a SCSI host for
675  * each USB device for the moment.  Can implement this by walking up the
676  * USB hierarchy until we find a USB host.
677  */
678 static int uas_probe(struct usb_interface *intf, const struct usb_device_id *id)
679 {
680 	int result;
681 	struct Scsi_Host *shost;
682 	struct uas_dev_info *devinfo;
683 	struct usb_device *udev = interface_to_usbdev(intf);
684 
685 	if (uas_switch_interface(udev, intf))
686 		return -ENODEV;
687 
688 	devinfo = kmalloc(sizeof(struct uas_dev_info), GFP_KERNEL);
689 	if (!devinfo)
690 		return -ENOMEM;
691 
692 	result = -ENOMEM;
693 	shost = scsi_host_alloc(&uas_host_template, sizeof(void *));
694 	if (!shost)
695 		goto free;
696 
697 	shost->max_cmd_len = 16 + 252;
698 	shost->max_id = 1;
699 	shost->sg_tablesize = udev->bus->sg_tablesize;
700 
701 	result = scsi_add_host(shost, &intf->dev);
702 	if (result)
703 		goto free;
704 	shost->hostdata[0] = (unsigned long)devinfo;
705 
706 	devinfo->intf = intf;
707 	devinfo->udev = udev;
708 	uas_configure_endpoints(devinfo);
709 
710 	scsi_scan_host(shost);
711 	usb_set_intfdata(intf, shost);
712 	return result;
713  free:
714 	kfree(devinfo);
715 	if (shost)
716 		scsi_host_put(shost);
717 	return result;
718 }
719 
720 static int uas_pre_reset(struct usb_interface *intf)
721 {
722 /* XXX: Need to return 1 if it's not our device in error handling */
723 	return 0;
724 }
725 
726 static int uas_post_reset(struct usb_interface *intf)
727 {
728 /* XXX: Need to return 1 if it's not our device in error handling */
729 	return 0;
730 }
731 
732 static void uas_disconnect(struct usb_interface *intf)
733 {
734 	struct usb_device *udev = interface_to_usbdev(intf);
735 	struct usb_host_endpoint *eps[3];
736 	struct Scsi_Host *shost = usb_get_intfdata(intf);
737 	struct uas_dev_info *devinfo = (void *)shost->hostdata[0];
738 
739 	scsi_remove_host(shost);
740 
741 	eps[0] = usb_pipe_endpoint(udev, devinfo->status_pipe);
742 	eps[1] = usb_pipe_endpoint(udev, devinfo->data_in_pipe);
743 	eps[2] = usb_pipe_endpoint(udev, devinfo->data_out_pipe);
744 	usb_free_streams(intf, eps, 3, GFP_KERNEL);
745 
746 	kfree(devinfo);
747 }
748 
749 /*
750  * XXX: Should this plug into libusual so we can auto-upgrade devices from
751  * Bulk-Only to UAS?
752  */
753 static struct usb_driver uas_driver = {
754 	.name = "uas",
755 	.probe = uas_probe,
756 	.disconnect = uas_disconnect,
757 	.pre_reset = uas_pre_reset,
758 	.post_reset = uas_post_reset,
759 	.id_table = uas_usb_ids,
760 };
761 
762 static int uas_init(void)
763 {
764 	return usb_register(&uas_driver);
765 }
766 
767 static void uas_exit(void)
768 {
769 	usb_deregister(&uas_driver);
770 }
771 
772 module_init(uas_init);
773 module_exit(uas_exit);
774 
775 MODULE_LICENSE("GPL");
776 MODULE_AUTHOR("Matthew Wilcox and Sarah Sharp");
777