xref: /linux/drivers/usb/host/xhci-dbgcap.c (revision ee057c8c194b9283f4137b253b70e292693a39f0)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * xhci-dbgcap.c - xHCI debug capability support
4  *
5  * Copyright (C) 2017 Intel Corporation
6  *
7  * Author: Lu Baolu <baolu.lu@linux.intel.com>
8  */
9 #include <linux/bug.h>
10 #include <linux/device.h>
11 #include <linux/dma-mapping.h>
12 #include <linux/errno.h>
13 #include <linux/kstrtox.h>
14 #include <linux/list.h>
15 #include <linux/nls.h>
16 #include <linux/pm_runtime.h>
17 #include <linux/slab.h>
18 #include <linux/spinlock.h>
19 #include <linux/string.h>
20 #include <linux/sysfs.h>
21 #include <linux/types.h>
22 #include <linux/workqueue.h>
23 
24 #include <linux/io-64-nonatomic-lo-hi.h>
25 
26 #include <asm/byteorder.h>
27 
28 #include "xhci.h"
29 #include "xhci-trace.h"
30 #include "xhci-dbgcap.h"
31 
32 static void dbc_free_ctx(struct device *dev, struct xhci_container_ctx *ctx)
33 {
34 	if (!ctx)
35 		return;
36 	dma_free_coherent(dev, ctx->size, ctx->bytes, ctx->dma);
37 	kfree(ctx);
38 }
39 
40 /* we use only one segment for DbC rings */
41 static void dbc_ring_free(struct device *dev, struct xhci_ring *ring)
42 {
43 	if (!ring)
44 		return;
45 
46 	if (ring->first_seg) {
47 		dma_free_coherent(dev, TRB_SEGMENT_SIZE,
48 				  ring->first_seg->trbs,
49 				  ring->first_seg->dma);
50 		kfree(ring->first_seg);
51 	}
52 	kfree(ring);
53 }
54 
55 static u32 xhci_dbc_populate_strings(struct dbc_str_descs *strings)
56 {
57 	struct usb_string_descriptor	*s_desc;
58 	u32				string_length;
59 
60 	/* Serial string: */
61 	s_desc = (struct usb_string_descriptor *)strings->serial;
62 	utf8s_to_utf16s(DBC_STRING_SERIAL, strlen(DBC_STRING_SERIAL),
63 			UTF16_LITTLE_ENDIAN, (wchar_t *)s_desc->wData,
64 			DBC_MAX_STRING_LENGTH);
65 
66 	s_desc->bLength		= (strlen(DBC_STRING_SERIAL) + 1) * 2;
67 	s_desc->bDescriptorType	= USB_DT_STRING;
68 	string_length		= s_desc->bLength;
69 	string_length		<<= 8;
70 
71 	/* Product string: */
72 	s_desc = (struct usb_string_descriptor *)strings->product;
73 	utf8s_to_utf16s(DBC_STRING_PRODUCT, strlen(DBC_STRING_PRODUCT),
74 			UTF16_LITTLE_ENDIAN, (wchar_t *)s_desc->wData,
75 			DBC_MAX_STRING_LENGTH);
76 
77 	s_desc->bLength		= (strlen(DBC_STRING_PRODUCT) + 1) * 2;
78 	s_desc->bDescriptorType	= USB_DT_STRING;
79 	string_length		+= s_desc->bLength;
80 	string_length		<<= 8;
81 
82 	/* Manufacture string: */
83 	s_desc = (struct usb_string_descriptor *)strings->manufacturer;
84 	utf8s_to_utf16s(DBC_STRING_MANUFACTURER,
85 			strlen(DBC_STRING_MANUFACTURER),
86 			UTF16_LITTLE_ENDIAN, (wchar_t *)s_desc->wData,
87 			DBC_MAX_STRING_LENGTH);
88 
89 	s_desc->bLength		= (strlen(DBC_STRING_MANUFACTURER) + 1) * 2;
90 	s_desc->bDescriptorType	= USB_DT_STRING;
91 	string_length		+= s_desc->bLength;
92 	string_length		<<= 8;
93 
94 	/* String0: */
95 	strings->string0[0]	= 4;
96 	strings->string0[1]	= USB_DT_STRING;
97 	strings->string0[2]	= 0x09;
98 	strings->string0[3]	= 0x04;
99 	string_length		+= 4;
100 
101 	return string_length;
102 }
103 
104 static void xhci_dbc_init_contexts(struct xhci_dbc *dbc, u32 string_length)
105 {
106 	struct dbc_info_context	*info;
107 	struct xhci_ep_ctx	*ep_ctx;
108 	u32			dev_info;
109 	dma_addr_t		deq, dma;
110 	unsigned int		max_burst;
111 
112 	if (!dbc)
113 		return;
114 
115 	/* Populate info Context: */
116 	info			= (struct dbc_info_context *)dbc->ctx->bytes;
117 	dma			= dbc->string_dma;
118 	info->string0		= cpu_to_le64(dma);
119 	info->manufacturer	= cpu_to_le64(dma + DBC_MAX_STRING_LENGTH);
120 	info->product		= cpu_to_le64(dma + DBC_MAX_STRING_LENGTH * 2);
121 	info->serial		= cpu_to_le64(dma + DBC_MAX_STRING_LENGTH * 3);
122 	info->length		= cpu_to_le32(string_length);
123 
124 	/* Populate bulk out endpoint context: */
125 	ep_ctx			= dbc_bulkout_ctx(dbc);
126 	max_burst		= DBC_CTRL_MAXBURST(readl(&dbc->regs->control));
127 	deq			= dbc_bulkout_enq(dbc);
128 	ep_ctx->ep_info		= 0;
129 	ep_ctx->ep_info2	= dbc_epctx_info2(BULK_OUT_EP, 1024, max_burst);
130 	ep_ctx->deq		= cpu_to_le64(deq | dbc->ring_out->cycle_state);
131 
132 	/* Populate bulk in endpoint context: */
133 	ep_ctx			= dbc_bulkin_ctx(dbc);
134 	deq			= dbc_bulkin_enq(dbc);
135 	ep_ctx->ep_info		= 0;
136 	ep_ctx->ep_info2	= dbc_epctx_info2(BULK_IN_EP, 1024, max_burst);
137 	ep_ctx->deq		= cpu_to_le64(deq | dbc->ring_in->cycle_state);
138 
139 	/* Set DbC context and info registers: */
140 	lo_hi_writeq(dbc->ctx->dma, &dbc->regs->dccp);
141 
142 	dev_info = (dbc->idVendor << 16) | dbc->bInterfaceProtocol;
143 	writel(dev_info, &dbc->regs->devinfo1);
144 
145 	dev_info = (dbc->bcdDevice << 16) | dbc->idProduct;
146 	writel(dev_info, &dbc->regs->devinfo2);
147 }
148 
149 static void xhci_dbc_giveback(struct dbc_request *req, int status)
150 	__releases(&dbc->lock)
151 	__acquires(&dbc->lock)
152 {
153 	struct xhci_dbc		*dbc = req->dbc;
154 	struct device		*dev = dbc->dev;
155 
156 	list_del_init(&req->list_pending);
157 	req->trb_dma = 0;
158 	req->trb = NULL;
159 
160 	if (req->status == -EINPROGRESS)
161 		req->status = status;
162 
163 	trace_xhci_dbc_giveback_request(req);
164 
165 	dma_unmap_single(dev,
166 			 req->dma,
167 			 req->length,
168 			 dbc_ep_dma_direction(req));
169 
170 	/* Give back the transfer request: */
171 	spin_unlock(&dbc->lock);
172 	req->complete(dbc, req);
173 	spin_lock(&dbc->lock);
174 }
175 
176 static void xhci_dbc_flush_single_request(struct dbc_request *req)
177 {
178 	union xhci_trb	*trb = req->trb;
179 
180 	trb->generic.field[0]	= 0;
181 	trb->generic.field[1]	= 0;
182 	trb->generic.field[2]	= 0;
183 	trb->generic.field[3]	&= cpu_to_le32(TRB_CYCLE);
184 	trb->generic.field[3]	|= cpu_to_le32(TRB_TYPE(TRB_TR_NOOP));
185 
186 	xhci_dbc_giveback(req, -ESHUTDOWN);
187 }
188 
189 static void xhci_dbc_flush_endpoint_requests(struct dbc_ep *dep)
190 {
191 	struct dbc_request	*req, *tmp;
192 
193 	list_for_each_entry_safe(req, tmp, &dep->list_pending, list_pending)
194 		xhci_dbc_flush_single_request(req);
195 }
196 
197 static void xhci_dbc_flush_requests(struct xhci_dbc *dbc)
198 {
199 	xhci_dbc_flush_endpoint_requests(&dbc->eps[BULK_OUT]);
200 	xhci_dbc_flush_endpoint_requests(&dbc->eps[BULK_IN]);
201 }
202 
203 struct dbc_request *
204 dbc_alloc_request(struct xhci_dbc *dbc, unsigned int direction, gfp_t flags)
205 {
206 	struct dbc_request	*req;
207 
208 	if (direction != BULK_IN &&
209 	    direction != BULK_OUT)
210 		return NULL;
211 
212 	if (!dbc)
213 		return NULL;
214 
215 	req = kzalloc(sizeof(*req), flags);
216 	if (!req)
217 		return NULL;
218 
219 	req->dbc = dbc;
220 	INIT_LIST_HEAD(&req->list_pending);
221 	INIT_LIST_HEAD(&req->list_pool);
222 	req->direction = direction;
223 
224 	trace_xhci_dbc_alloc_request(req);
225 
226 	return req;
227 }
228 
229 void
230 dbc_free_request(struct dbc_request *req)
231 {
232 	trace_xhci_dbc_free_request(req);
233 
234 	kfree(req);
235 }
236 
237 static void
238 xhci_dbc_queue_trb(struct xhci_ring *ring, u32 field1,
239 		   u32 field2, u32 field3, u32 field4)
240 {
241 	union xhci_trb		*trb, *next;
242 
243 	trb = ring->enqueue;
244 	trb->generic.field[0]	= cpu_to_le32(field1);
245 	trb->generic.field[1]	= cpu_to_le32(field2);
246 	trb->generic.field[2]	= cpu_to_le32(field3);
247 	trb->generic.field[3]	= cpu_to_le32(field4);
248 
249 	trace_xhci_dbc_gadget_ep_queue(ring, &trb->generic);
250 
251 	ring->num_trbs_free--;
252 	next = ++(ring->enqueue);
253 	if (TRB_TYPE_LINK_LE32(next->link.control)) {
254 		next->link.control ^= cpu_to_le32(TRB_CYCLE);
255 		ring->enqueue = ring->enq_seg->trbs;
256 		ring->cycle_state ^= 1;
257 	}
258 }
259 
260 static int xhci_dbc_queue_bulk_tx(struct dbc_ep *dep,
261 				  struct dbc_request *req)
262 {
263 	u64			addr;
264 	union xhci_trb		*trb;
265 	unsigned int		num_trbs;
266 	struct xhci_dbc		*dbc = req->dbc;
267 	struct xhci_ring	*ring = dep->ring;
268 	u32			length, control, cycle;
269 
270 	num_trbs = count_trbs(req->dma, req->length);
271 	WARN_ON(num_trbs != 1);
272 	if (ring->num_trbs_free < num_trbs)
273 		return -EBUSY;
274 
275 	addr	= req->dma;
276 	trb	= ring->enqueue;
277 	cycle	= ring->cycle_state;
278 	length	= TRB_LEN(req->length);
279 	control	= TRB_TYPE(TRB_NORMAL) | TRB_IOC;
280 
281 	if (cycle)
282 		control &= cpu_to_le32(~TRB_CYCLE);
283 	else
284 		control |= cpu_to_le32(TRB_CYCLE);
285 
286 	req->trb = ring->enqueue;
287 	req->trb_dma = xhci_trb_virt_to_dma(ring->enq_seg, ring->enqueue);
288 	xhci_dbc_queue_trb(ring,
289 			   lower_32_bits(addr),
290 			   upper_32_bits(addr),
291 			   length, control);
292 
293 	/*
294 	 * Add a barrier between writes of trb fields and flipping
295 	 * the cycle bit:
296 	 */
297 	wmb();
298 
299 	if (cycle)
300 		trb->generic.field[3] |= cpu_to_le32(TRB_CYCLE);
301 	else
302 		trb->generic.field[3] &= cpu_to_le32(~TRB_CYCLE);
303 
304 	writel(DBC_DOOR_BELL_TARGET(dep->direction), &dbc->regs->doorbell);
305 
306 	return 0;
307 }
308 
309 static int
310 dbc_ep_do_queue(struct dbc_request *req)
311 {
312 	int			ret;
313 	struct xhci_dbc		*dbc = req->dbc;
314 	struct device		*dev = dbc->dev;
315 	struct dbc_ep		*dep = &dbc->eps[req->direction];
316 
317 	if (!req->length || !req->buf)
318 		return -EINVAL;
319 
320 	req->actual		= 0;
321 	req->status		= -EINPROGRESS;
322 
323 	req->dma = dma_map_single(dev,
324 				  req->buf,
325 				  req->length,
326 				  dbc_ep_dma_direction(dep));
327 	if (dma_mapping_error(dev, req->dma)) {
328 		dev_err(dbc->dev, "failed to map buffer\n");
329 		return -EFAULT;
330 	}
331 
332 	ret = xhci_dbc_queue_bulk_tx(dep, req);
333 	if (ret) {
334 		dev_err(dbc->dev, "failed to queue trbs\n");
335 		dma_unmap_single(dev,
336 				 req->dma,
337 				 req->length,
338 				 dbc_ep_dma_direction(dep));
339 		return -EFAULT;
340 	}
341 
342 	list_add_tail(&req->list_pending, &dep->list_pending);
343 
344 	return 0;
345 }
346 
347 int dbc_ep_queue(struct dbc_request *req)
348 {
349 	unsigned long		flags;
350 	struct xhci_dbc		*dbc = req->dbc;
351 	int			ret = -ESHUTDOWN;
352 
353 	if (!dbc)
354 		return -ENODEV;
355 
356 	if (req->direction != BULK_IN &&
357 	    req->direction != BULK_OUT)
358 		return -EINVAL;
359 
360 	spin_lock_irqsave(&dbc->lock, flags);
361 	if (dbc->state == DS_CONFIGURED)
362 		ret = dbc_ep_do_queue(req);
363 	spin_unlock_irqrestore(&dbc->lock, flags);
364 
365 	mod_delayed_work(system_wq, &dbc->event_work, 0);
366 
367 	trace_xhci_dbc_queue_request(req);
368 
369 	return ret;
370 }
371 
372 static inline void xhci_dbc_do_eps_init(struct xhci_dbc *dbc, bool direction)
373 {
374 	struct dbc_ep		*dep;
375 
376 	dep			= &dbc->eps[direction];
377 	dep->dbc		= dbc;
378 	dep->direction		= direction;
379 	dep->ring		= direction ? dbc->ring_in : dbc->ring_out;
380 
381 	INIT_LIST_HEAD(&dep->list_pending);
382 }
383 
384 static void xhci_dbc_eps_init(struct xhci_dbc *dbc)
385 {
386 	xhci_dbc_do_eps_init(dbc, BULK_OUT);
387 	xhci_dbc_do_eps_init(dbc, BULK_IN);
388 }
389 
390 static void xhci_dbc_eps_exit(struct xhci_dbc *dbc)
391 {
392 	memset(dbc->eps, 0, sizeof_field(struct xhci_dbc, eps));
393 }
394 
395 static int dbc_erst_alloc(struct device *dev, struct xhci_ring *evt_ring,
396 		    struct xhci_erst *erst, gfp_t flags)
397 {
398 	erst->entries = dma_alloc_coherent(dev, sizeof(*erst->entries),
399 					   &erst->erst_dma_addr, flags);
400 	if (!erst->entries)
401 		return -ENOMEM;
402 
403 	erst->num_entries = 1;
404 	erst->entries[0].seg_addr = cpu_to_le64(evt_ring->first_seg->dma);
405 	erst->entries[0].seg_size = cpu_to_le32(TRBS_PER_SEGMENT);
406 	erst->entries[0].rsvd = 0;
407 	return 0;
408 }
409 
410 static void dbc_erst_free(struct device *dev, struct xhci_erst *erst)
411 {
412 	dma_free_coherent(dev, sizeof(*erst->entries), erst->entries,
413 			  erst->erst_dma_addr);
414 	erst->entries = NULL;
415 }
416 
417 static struct xhci_container_ctx *
418 dbc_alloc_ctx(struct device *dev, gfp_t flags)
419 {
420 	struct xhci_container_ctx *ctx;
421 
422 	ctx = kzalloc(sizeof(*ctx), flags);
423 	if (!ctx)
424 		return NULL;
425 
426 	/* xhci 7.6.9, all three contexts; info, ep-out and ep-in. Each 64 bytes*/
427 	ctx->size = 3 * DBC_CONTEXT_SIZE;
428 	ctx->bytes = dma_alloc_coherent(dev, ctx->size, &ctx->dma, flags);
429 	if (!ctx->bytes) {
430 		kfree(ctx);
431 		return NULL;
432 	}
433 	return ctx;
434 }
435 
436 static struct xhci_ring *
437 xhci_dbc_ring_alloc(struct device *dev, enum xhci_ring_type type, gfp_t flags)
438 {
439 	struct xhci_ring *ring;
440 	struct xhci_segment *seg;
441 	dma_addr_t dma;
442 
443 	ring = kzalloc(sizeof(*ring), flags);
444 	if (!ring)
445 		return NULL;
446 
447 	ring->num_segs = 1;
448 	ring->type = type;
449 
450 	seg = kzalloc(sizeof(*seg), flags);
451 	if (!seg)
452 		goto seg_fail;
453 
454 	ring->first_seg = seg;
455 	ring->last_seg = seg;
456 	seg->next = seg;
457 
458 	seg->trbs = dma_alloc_coherent(dev, TRB_SEGMENT_SIZE, &dma, flags);
459 	if (!seg->trbs)
460 		goto dma_fail;
461 
462 	seg->dma = dma;
463 
464 	/* Only event ring does not use link TRB */
465 	if (type != TYPE_EVENT) {
466 		union xhci_trb *trb = &seg->trbs[TRBS_PER_SEGMENT - 1];
467 
468 		trb->link.segment_ptr = cpu_to_le64(dma);
469 		trb->link.control = cpu_to_le32(LINK_TOGGLE | TRB_TYPE(TRB_LINK));
470 	}
471 	INIT_LIST_HEAD(&ring->td_list);
472 	xhci_initialize_ring_info(ring, 1);
473 	return ring;
474 dma_fail:
475 	kfree(seg);
476 seg_fail:
477 	kfree(ring);
478 	return NULL;
479 }
480 
481 static int xhci_dbc_mem_init(struct xhci_dbc *dbc, gfp_t flags)
482 {
483 	int			ret;
484 	dma_addr_t		deq;
485 	u32			string_length;
486 	struct device		*dev = dbc->dev;
487 
488 	/* Allocate various rings for events and transfers: */
489 	dbc->ring_evt = xhci_dbc_ring_alloc(dev, TYPE_EVENT, flags);
490 	if (!dbc->ring_evt)
491 		goto evt_fail;
492 
493 	dbc->ring_in = xhci_dbc_ring_alloc(dev, TYPE_BULK, flags);
494 	if (!dbc->ring_in)
495 		goto in_fail;
496 
497 	dbc->ring_out = xhci_dbc_ring_alloc(dev, TYPE_BULK, flags);
498 	if (!dbc->ring_out)
499 		goto out_fail;
500 
501 	/* Allocate and populate ERST: */
502 	ret = dbc_erst_alloc(dev, dbc->ring_evt, &dbc->erst, flags);
503 	if (ret)
504 		goto erst_fail;
505 
506 	/* Allocate context data structure: */
507 	dbc->ctx = dbc_alloc_ctx(dev, flags); /* was sysdev, and is still */
508 	if (!dbc->ctx)
509 		goto ctx_fail;
510 
511 	/* Allocate the string table: */
512 	dbc->string_size = sizeof(*dbc->string);
513 	dbc->string = dma_alloc_coherent(dev, dbc->string_size,
514 					 &dbc->string_dma, flags);
515 	if (!dbc->string)
516 		goto string_fail;
517 
518 	/* Setup ERST register: */
519 	writel(dbc->erst.num_entries, &dbc->regs->ersts);
520 
521 	lo_hi_writeq(dbc->erst.erst_dma_addr, &dbc->regs->erstba);
522 	deq = xhci_trb_virt_to_dma(dbc->ring_evt->deq_seg,
523 				   dbc->ring_evt->dequeue);
524 	lo_hi_writeq(deq, &dbc->regs->erdp);
525 
526 	/* Setup strings and contexts: */
527 	string_length = xhci_dbc_populate_strings(dbc->string);
528 	xhci_dbc_init_contexts(dbc, string_length);
529 
530 	xhci_dbc_eps_init(dbc);
531 	dbc->state = DS_INITIALIZED;
532 
533 	return 0;
534 
535 string_fail:
536 	dbc_free_ctx(dev, dbc->ctx);
537 	dbc->ctx = NULL;
538 ctx_fail:
539 	dbc_erst_free(dev, &dbc->erst);
540 erst_fail:
541 	dbc_ring_free(dev, dbc->ring_out);
542 	dbc->ring_out = NULL;
543 out_fail:
544 	dbc_ring_free(dev, dbc->ring_in);
545 	dbc->ring_in = NULL;
546 in_fail:
547 	dbc_ring_free(dev, dbc->ring_evt);
548 	dbc->ring_evt = NULL;
549 evt_fail:
550 	return -ENOMEM;
551 }
552 
553 static void xhci_dbc_mem_cleanup(struct xhci_dbc *dbc)
554 {
555 	if (!dbc)
556 		return;
557 
558 	xhci_dbc_eps_exit(dbc);
559 
560 	dma_free_coherent(dbc->dev, dbc->string_size, dbc->string, dbc->string_dma);
561 	dbc->string = NULL;
562 
563 	dbc_free_ctx(dbc->dev, dbc->ctx);
564 	dbc->ctx = NULL;
565 
566 	dbc_erst_free(dbc->dev, &dbc->erst);
567 	dbc_ring_free(dbc->dev, dbc->ring_out);
568 	dbc_ring_free(dbc->dev, dbc->ring_in);
569 	dbc_ring_free(dbc->dev, dbc->ring_evt);
570 	dbc->ring_in = NULL;
571 	dbc->ring_out = NULL;
572 	dbc->ring_evt = NULL;
573 }
574 
575 static int xhci_do_dbc_start(struct xhci_dbc *dbc)
576 {
577 	int			ret;
578 	u32			ctrl;
579 
580 	if (dbc->state != DS_DISABLED)
581 		return -EINVAL;
582 
583 	writel(0, &dbc->regs->control);
584 	ret = xhci_handshake(&dbc->regs->control,
585 			     DBC_CTRL_DBC_ENABLE,
586 			     0, 1000);
587 	if (ret)
588 		return ret;
589 
590 	ret = xhci_dbc_mem_init(dbc, GFP_ATOMIC);
591 	if (ret)
592 		return ret;
593 
594 	ctrl = readl(&dbc->regs->control);
595 	writel(ctrl | DBC_CTRL_DBC_ENABLE | DBC_CTRL_PORT_ENABLE,
596 	       &dbc->regs->control);
597 	ret = xhci_handshake(&dbc->regs->control,
598 			     DBC_CTRL_DBC_ENABLE,
599 			     DBC_CTRL_DBC_ENABLE, 1000);
600 	if (ret)
601 		return ret;
602 
603 	dbc->state = DS_ENABLED;
604 
605 	return 0;
606 }
607 
608 static int xhci_do_dbc_stop(struct xhci_dbc *dbc)
609 {
610 	if (dbc->state == DS_DISABLED)
611 		return -EINVAL;
612 
613 	writel(0, &dbc->regs->control);
614 	dbc->state = DS_DISABLED;
615 
616 	return 0;
617 }
618 
619 static int xhci_dbc_start(struct xhci_dbc *dbc)
620 {
621 	int			ret;
622 	unsigned long		flags;
623 
624 	WARN_ON(!dbc);
625 
626 	pm_runtime_get_sync(dbc->dev); /* note this was self.controller */
627 
628 	spin_lock_irqsave(&dbc->lock, flags);
629 	ret = xhci_do_dbc_start(dbc);
630 	spin_unlock_irqrestore(&dbc->lock, flags);
631 
632 	if (ret) {
633 		pm_runtime_put(dbc->dev); /* note this was self.controller */
634 		return ret;
635 	}
636 
637 	return mod_delayed_work(system_wq, &dbc->event_work,
638 				msecs_to_jiffies(dbc->poll_interval));
639 }
640 
641 static void xhci_dbc_stop(struct xhci_dbc *dbc)
642 {
643 	int ret;
644 	unsigned long		flags;
645 
646 	WARN_ON(!dbc);
647 
648 	switch (dbc->state) {
649 	case DS_DISABLED:
650 		return;
651 	case DS_CONFIGURED:
652 	case DS_STALLED:
653 		if (dbc->driver->disconnect)
654 			dbc->driver->disconnect(dbc);
655 		break;
656 	default:
657 		break;
658 	}
659 
660 	cancel_delayed_work_sync(&dbc->event_work);
661 
662 	spin_lock_irqsave(&dbc->lock, flags);
663 	ret = xhci_do_dbc_stop(dbc);
664 	spin_unlock_irqrestore(&dbc->lock, flags);
665 	if (ret)
666 		return;
667 
668 	xhci_dbc_mem_cleanup(dbc);
669 	pm_runtime_put_sync(dbc->dev); /* note, was self.controller */
670 }
671 
672 static void
673 dbc_handle_port_status(struct xhci_dbc *dbc, union xhci_trb *event)
674 {
675 	u32			portsc;
676 
677 	portsc = readl(&dbc->regs->portsc);
678 	if (portsc & DBC_PORTSC_CONN_CHANGE)
679 		dev_info(dbc->dev, "DbC port connect change\n");
680 
681 	if (portsc & DBC_PORTSC_RESET_CHANGE)
682 		dev_info(dbc->dev, "DbC port reset change\n");
683 
684 	if (portsc & DBC_PORTSC_LINK_CHANGE)
685 		dev_info(dbc->dev, "DbC port link status change\n");
686 
687 	if (portsc & DBC_PORTSC_CONFIG_CHANGE)
688 		dev_info(dbc->dev, "DbC config error change\n");
689 
690 	/* Port reset change bit will be cleared in other place: */
691 	writel(portsc & ~DBC_PORTSC_RESET_CHANGE, &dbc->regs->portsc);
692 }
693 
694 static void dbc_handle_xfer_event(struct xhci_dbc *dbc, union xhci_trb *event)
695 {
696 	struct dbc_ep		*dep;
697 	struct xhci_ring	*ring;
698 	int			ep_id;
699 	int			status;
700 	u32			comp_code;
701 	size_t			remain_length;
702 	struct dbc_request	*req = NULL, *r;
703 
704 	comp_code	= GET_COMP_CODE(le32_to_cpu(event->generic.field[2]));
705 	remain_length	= EVENT_TRB_LEN(le32_to_cpu(event->generic.field[2]));
706 	ep_id		= TRB_TO_EP_ID(le32_to_cpu(event->generic.field[3]));
707 	dep		= (ep_id == EPID_OUT) ?
708 				get_out_ep(dbc) : get_in_ep(dbc);
709 	ring		= dep->ring;
710 
711 	switch (comp_code) {
712 	case COMP_SUCCESS:
713 		remain_length = 0;
714 		fallthrough;
715 	case COMP_SHORT_PACKET:
716 		status = 0;
717 		break;
718 	case COMP_TRB_ERROR:
719 	case COMP_BABBLE_DETECTED_ERROR:
720 	case COMP_USB_TRANSACTION_ERROR:
721 	case COMP_STALL_ERROR:
722 		dev_warn(dbc->dev, "tx error %d detected\n", comp_code);
723 		status = -comp_code;
724 		break;
725 	default:
726 		dev_err(dbc->dev, "unknown tx error %d\n", comp_code);
727 		status = -comp_code;
728 		break;
729 	}
730 
731 	/* Match the pending request: */
732 	list_for_each_entry(r, &dep->list_pending, list_pending) {
733 		if (r->trb_dma == event->trans_event.buffer) {
734 			req = r;
735 			break;
736 		}
737 	}
738 
739 	if (!req) {
740 		dev_warn(dbc->dev, "no matched request\n");
741 		return;
742 	}
743 
744 	trace_xhci_dbc_handle_transfer(ring, &req->trb->generic);
745 
746 	ring->num_trbs_free++;
747 	req->actual = req->length - remain_length;
748 	xhci_dbc_giveback(req, status);
749 }
750 
751 static void inc_evt_deq(struct xhci_ring *ring)
752 {
753 	/* If on the last TRB of the segment go back to the beginning */
754 	if (ring->dequeue == &ring->deq_seg->trbs[TRBS_PER_SEGMENT - 1]) {
755 		ring->cycle_state ^= 1;
756 		ring->dequeue = ring->deq_seg->trbs;
757 		return;
758 	}
759 	ring->dequeue++;
760 }
761 
762 static enum evtreturn xhci_dbc_do_handle_events(struct xhci_dbc *dbc)
763 {
764 	dma_addr_t		deq;
765 	struct dbc_ep		*dep;
766 	union xhci_trb		*evt;
767 	u32			ctrl, portsc;
768 	bool			update_erdp = false;
769 
770 	/* DbC state machine: */
771 	switch (dbc->state) {
772 	case DS_DISABLED:
773 	case DS_INITIALIZED:
774 
775 		return EVT_ERR;
776 	case DS_ENABLED:
777 		portsc = readl(&dbc->regs->portsc);
778 		if (portsc & DBC_PORTSC_CONN_STATUS) {
779 			dbc->state = DS_CONNECTED;
780 			dev_info(dbc->dev, "DbC connected\n");
781 		}
782 
783 		return EVT_DONE;
784 	case DS_CONNECTED:
785 		ctrl = readl(&dbc->regs->control);
786 		if (ctrl & DBC_CTRL_DBC_RUN) {
787 			dbc->state = DS_CONFIGURED;
788 			dev_info(dbc->dev, "DbC configured\n");
789 			portsc = readl(&dbc->regs->portsc);
790 			writel(portsc, &dbc->regs->portsc);
791 			return EVT_GSER;
792 		}
793 
794 		return EVT_DONE;
795 	case DS_CONFIGURED:
796 		/* Handle cable unplug event: */
797 		portsc = readl(&dbc->regs->portsc);
798 		if (!(portsc & DBC_PORTSC_PORT_ENABLED) &&
799 		    !(portsc & DBC_PORTSC_CONN_STATUS)) {
800 			dev_info(dbc->dev, "DbC cable unplugged\n");
801 			dbc->state = DS_ENABLED;
802 			xhci_dbc_flush_requests(dbc);
803 
804 			return EVT_DISC;
805 		}
806 
807 		/* Handle debug port reset event: */
808 		if (portsc & DBC_PORTSC_RESET_CHANGE) {
809 			dev_info(dbc->dev, "DbC port reset\n");
810 			writel(portsc, &dbc->regs->portsc);
811 			dbc->state = DS_ENABLED;
812 			xhci_dbc_flush_requests(dbc);
813 
814 			return EVT_DISC;
815 		}
816 
817 		/* Handle endpoint stall event: */
818 		ctrl = readl(&dbc->regs->control);
819 		if ((ctrl & DBC_CTRL_HALT_IN_TR) ||
820 		    (ctrl & DBC_CTRL_HALT_OUT_TR)) {
821 			dev_info(dbc->dev, "DbC Endpoint stall\n");
822 			dbc->state = DS_STALLED;
823 
824 			if (ctrl & DBC_CTRL_HALT_IN_TR) {
825 				dep = get_in_ep(dbc);
826 				xhci_dbc_flush_endpoint_requests(dep);
827 			}
828 
829 			if (ctrl & DBC_CTRL_HALT_OUT_TR) {
830 				dep = get_out_ep(dbc);
831 				xhci_dbc_flush_endpoint_requests(dep);
832 			}
833 
834 			return EVT_DONE;
835 		}
836 
837 		/* Clear DbC run change bit: */
838 		if (ctrl & DBC_CTRL_DBC_RUN_CHANGE) {
839 			writel(ctrl, &dbc->regs->control);
840 			ctrl = readl(&dbc->regs->control);
841 		}
842 
843 		break;
844 	case DS_STALLED:
845 		ctrl = readl(&dbc->regs->control);
846 		if (!(ctrl & DBC_CTRL_HALT_IN_TR) &&
847 		    !(ctrl & DBC_CTRL_HALT_OUT_TR) &&
848 		    (ctrl & DBC_CTRL_DBC_RUN)) {
849 			dbc->state = DS_CONFIGURED;
850 			break;
851 		}
852 
853 		return EVT_DONE;
854 	default:
855 		dev_err(dbc->dev, "Unknown DbC state %d\n", dbc->state);
856 		break;
857 	}
858 
859 	/* Handle the events in the event ring: */
860 	evt = dbc->ring_evt->dequeue;
861 	while ((le32_to_cpu(evt->event_cmd.flags) & TRB_CYCLE) ==
862 			dbc->ring_evt->cycle_state) {
863 		/*
864 		 * Add a barrier between reading the cycle flag and any
865 		 * reads of the event's flags/data below:
866 		 */
867 		rmb();
868 
869 		trace_xhci_dbc_handle_event(dbc->ring_evt, &evt->generic);
870 
871 		switch (le32_to_cpu(evt->event_cmd.flags) & TRB_TYPE_BITMASK) {
872 		case TRB_TYPE(TRB_PORT_STATUS):
873 			dbc_handle_port_status(dbc, evt);
874 			break;
875 		case TRB_TYPE(TRB_TRANSFER):
876 			dbc_handle_xfer_event(dbc, evt);
877 			break;
878 		default:
879 			break;
880 		}
881 
882 		inc_evt_deq(dbc->ring_evt);
883 
884 		evt = dbc->ring_evt->dequeue;
885 		update_erdp = true;
886 	}
887 
888 	/* Update event ring dequeue pointer: */
889 	if (update_erdp) {
890 		deq = xhci_trb_virt_to_dma(dbc->ring_evt->deq_seg,
891 					   dbc->ring_evt->dequeue);
892 		lo_hi_writeq(deq, &dbc->regs->erdp);
893 	}
894 
895 	return EVT_DONE;
896 }
897 
898 static void xhci_dbc_handle_events(struct work_struct *work)
899 {
900 	enum evtreturn		evtr;
901 	struct xhci_dbc		*dbc;
902 	unsigned long		flags;
903 	unsigned int		poll_interval;
904 
905 	dbc = container_of(to_delayed_work(work), struct xhci_dbc, event_work);
906 	poll_interval = dbc->poll_interval;
907 
908 	spin_lock_irqsave(&dbc->lock, flags);
909 	evtr = xhci_dbc_do_handle_events(dbc);
910 	spin_unlock_irqrestore(&dbc->lock, flags);
911 
912 	switch (evtr) {
913 	case EVT_GSER:
914 		if (dbc->driver->configure)
915 			dbc->driver->configure(dbc);
916 		break;
917 	case EVT_DISC:
918 		if (dbc->driver->disconnect)
919 			dbc->driver->disconnect(dbc);
920 		break;
921 	case EVT_DONE:
922 		/* set fast poll rate if there are pending data transfers */
923 		if (!list_empty(&dbc->eps[BULK_OUT].list_pending) ||
924 		    !list_empty(&dbc->eps[BULK_IN].list_pending))
925 			poll_interval = 1;
926 		break;
927 	default:
928 		dev_info(dbc->dev, "stop handling dbc events\n");
929 		return;
930 	}
931 
932 	mod_delayed_work(system_wq, &dbc->event_work,
933 			 msecs_to_jiffies(poll_interval));
934 }
935 
936 static const char * const dbc_state_strings[DS_MAX] = {
937 	[DS_DISABLED] = "disabled",
938 	[DS_INITIALIZED] = "initialized",
939 	[DS_ENABLED] = "enabled",
940 	[DS_CONNECTED] = "connected",
941 	[DS_CONFIGURED] = "configured",
942 	[DS_STALLED] = "stalled",
943 };
944 
945 static ssize_t dbc_show(struct device *dev,
946 			struct device_attribute *attr,
947 			char *buf)
948 {
949 	struct xhci_dbc		*dbc;
950 	struct xhci_hcd		*xhci;
951 
952 	xhci = hcd_to_xhci(dev_get_drvdata(dev));
953 	dbc = xhci->dbc;
954 
955 	if (dbc->state >= ARRAY_SIZE(dbc_state_strings))
956 		return sysfs_emit(buf, "unknown\n");
957 
958 	return sysfs_emit(buf, "%s\n", dbc_state_strings[dbc->state]);
959 }
960 
961 static ssize_t dbc_store(struct device *dev,
962 			 struct device_attribute *attr,
963 			 const char *buf, size_t count)
964 {
965 	struct xhci_hcd		*xhci;
966 	struct xhci_dbc		*dbc;
967 
968 	xhci = hcd_to_xhci(dev_get_drvdata(dev));
969 	dbc = xhci->dbc;
970 
971 	if (sysfs_streq(buf, "enable"))
972 		xhci_dbc_start(dbc);
973 	else if (sysfs_streq(buf, "disable"))
974 		xhci_dbc_stop(dbc);
975 	else
976 		return -EINVAL;
977 
978 	return count;
979 }
980 
981 static ssize_t dbc_idVendor_show(struct device *dev,
982 			    struct device_attribute *attr,
983 			    char *buf)
984 {
985 	struct xhci_dbc		*dbc;
986 	struct xhci_hcd		*xhci;
987 
988 	xhci = hcd_to_xhci(dev_get_drvdata(dev));
989 	dbc = xhci->dbc;
990 
991 	return sysfs_emit(buf, "%04x\n", dbc->idVendor);
992 }
993 
994 static ssize_t dbc_idVendor_store(struct device *dev,
995 			     struct device_attribute *attr,
996 			     const char *buf, size_t size)
997 {
998 	struct xhci_dbc		*dbc;
999 	struct xhci_hcd		*xhci;
1000 	void __iomem		*ptr;
1001 	u16			value;
1002 	u32			dev_info;
1003 	int ret;
1004 
1005 	ret = kstrtou16(buf, 0, &value);
1006 	if (ret)
1007 		return ret;
1008 
1009 	xhci = hcd_to_xhci(dev_get_drvdata(dev));
1010 	dbc = xhci->dbc;
1011 	if (dbc->state != DS_DISABLED)
1012 		return -EBUSY;
1013 
1014 	dbc->idVendor = value;
1015 	ptr = &dbc->regs->devinfo1;
1016 	dev_info = readl(ptr);
1017 	dev_info = (dev_info & ~(0xffffu << 16)) | (value << 16);
1018 	writel(dev_info, ptr);
1019 
1020 	return size;
1021 }
1022 
1023 static ssize_t dbc_idProduct_show(struct device *dev,
1024 			    struct device_attribute *attr,
1025 			    char *buf)
1026 {
1027 	struct xhci_dbc         *dbc;
1028 	struct xhci_hcd         *xhci;
1029 
1030 	xhci = hcd_to_xhci(dev_get_drvdata(dev));
1031 	dbc = xhci->dbc;
1032 
1033 	return sysfs_emit(buf, "%04x\n", dbc->idProduct);
1034 }
1035 
1036 static ssize_t dbc_idProduct_store(struct device *dev,
1037 			     struct device_attribute *attr,
1038 			     const char *buf, size_t size)
1039 {
1040 	struct xhci_dbc         *dbc;
1041 	struct xhci_hcd         *xhci;
1042 	void __iomem		*ptr;
1043 	u32			dev_info;
1044 	u16			value;
1045 	int ret;
1046 
1047 	ret = kstrtou16(buf, 0, &value);
1048 	if (ret)
1049 		return ret;
1050 
1051 	xhci = hcd_to_xhci(dev_get_drvdata(dev));
1052 	dbc = xhci->dbc;
1053 	if (dbc->state != DS_DISABLED)
1054 		return -EBUSY;
1055 
1056 	dbc->idProduct = value;
1057 	ptr = &dbc->regs->devinfo2;
1058 	dev_info = readl(ptr);
1059 	dev_info = (dev_info & ~(0xffffu)) | value;
1060 	writel(dev_info, ptr);
1061 	return size;
1062 }
1063 
1064 static ssize_t dbc_bcdDevice_show(struct device *dev,
1065 				   struct device_attribute *attr,
1066 				   char *buf)
1067 {
1068 	struct xhci_dbc	*dbc;
1069 	struct xhci_hcd	*xhci;
1070 
1071 	xhci = hcd_to_xhci(dev_get_drvdata(dev));
1072 	dbc = xhci->dbc;
1073 
1074 	return sysfs_emit(buf, "%04x\n", dbc->bcdDevice);
1075 }
1076 
1077 static ssize_t dbc_bcdDevice_store(struct device *dev,
1078 				    struct device_attribute *attr,
1079 				    const char *buf, size_t size)
1080 {
1081 	struct xhci_dbc	*dbc;
1082 	struct xhci_hcd	*xhci;
1083 	void __iomem *ptr;
1084 	u32 dev_info;
1085 	u16 value;
1086 	int ret;
1087 
1088 	ret = kstrtou16(buf, 0, &value);
1089 	if (ret)
1090 		return ret;
1091 
1092 	xhci = hcd_to_xhci(dev_get_drvdata(dev));
1093 	dbc = xhci->dbc;
1094 	if (dbc->state != DS_DISABLED)
1095 		return -EBUSY;
1096 
1097 	dbc->bcdDevice = value;
1098 	ptr = &dbc->regs->devinfo2;
1099 	dev_info = readl(ptr);
1100 	dev_info = (dev_info & ~(0xffffu << 16)) | (value << 16);
1101 	writel(dev_info, ptr);
1102 
1103 	return size;
1104 }
1105 
1106 static ssize_t dbc_bInterfaceProtocol_show(struct device *dev,
1107 				 struct device_attribute *attr,
1108 				 char *buf)
1109 {
1110 	struct xhci_dbc	*dbc;
1111 	struct xhci_hcd	*xhci;
1112 
1113 	xhci = hcd_to_xhci(dev_get_drvdata(dev));
1114 	dbc = xhci->dbc;
1115 
1116 	return sysfs_emit(buf, "%02x\n", dbc->bInterfaceProtocol);
1117 }
1118 
1119 static ssize_t dbc_bInterfaceProtocol_store(struct device *dev,
1120 				  struct device_attribute *attr,
1121 				  const char *buf, size_t size)
1122 {
1123 	struct xhci_dbc *dbc;
1124 	struct xhci_hcd *xhci;
1125 	void __iomem *ptr;
1126 	u32 dev_info;
1127 	u8 value;
1128 	int ret;
1129 
1130 	/* bInterfaceProtocol is 8 bit, but... */
1131 	ret = kstrtou8(buf, 0, &value);
1132 	if (ret)
1133 		return ret;
1134 
1135 	/* ...xhci only supports values 0 and 1 */
1136 	if (value > 1)
1137 		return -EINVAL;
1138 
1139 	xhci = hcd_to_xhci(dev_get_drvdata(dev));
1140 	dbc = xhci->dbc;
1141 	if (dbc->state != DS_DISABLED)
1142 		return -EBUSY;
1143 
1144 	dbc->bInterfaceProtocol = value;
1145 	ptr = &dbc->regs->devinfo1;
1146 	dev_info = readl(ptr);
1147 	dev_info = (dev_info & ~(0xffu)) | value;
1148 	writel(dev_info, ptr);
1149 
1150 	return size;
1151 }
1152 
1153 static ssize_t dbc_poll_interval_ms_show(struct device *dev,
1154 					 struct device_attribute *attr,
1155 					 char *buf)
1156 {
1157 	struct xhci_dbc *dbc;
1158 	struct xhci_hcd *xhci;
1159 
1160 	xhci = hcd_to_xhci(dev_get_drvdata(dev));
1161 	dbc = xhci->dbc;
1162 
1163 	return sysfs_emit(buf, "%u\n", dbc->poll_interval);
1164 }
1165 
1166 static ssize_t dbc_poll_interval_ms_store(struct device *dev,
1167 					  struct device_attribute *attr,
1168 					  const char *buf, size_t size)
1169 {
1170 	struct xhci_dbc *dbc;
1171 	struct xhci_hcd *xhci;
1172 	u32 value;
1173 	int ret;
1174 
1175 	ret = kstrtou32(buf, 0, &value);
1176 	if (ret || value > DBC_POLL_INTERVAL_MAX)
1177 		return -EINVAL;
1178 
1179 	xhci = hcd_to_xhci(dev_get_drvdata(dev));
1180 	dbc = xhci->dbc;
1181 
1182 	dbc->poll_interval = value;
1183 
1184 	mod_delayed_work(system_wq, &dbc->event_work, 0);
1185 
1186 	return size;
1187 }
1188 
1189 static DEVICE_ATTR_RW(dbc);
1190 static DEVICE_ATTR_RW(dbc_idVendor);
1191 static DEVICE_ATTR_RW(dbc_idProduct);
1192 static DEVICE_ATTR_RW(dbc_bcdDevice);
1193 static DEVICE_ATTR_RW(dbc_bInterfaceProtocol);
1194 static DEVICE_ATTR_RW(dbc_poll_interval_ms);
1195 
1196 static struct attribute *dbc_dev_attrs[] = {
1197 	&dev_attr_dbc.attr,
1198 	&dev_attr_dbc_idVendor.attr,
1199 	&dev_attr_dbc_idProduct.attr,
1200 	&dev_attr_dbc_bcdDevice.attr,
1201 	&dev_attr_dbc_bInterfaceProtocol.attr,
1202 	&dev_attr_dbc_poll_interval_ms.attr,
1203 	NULL
1204 };
1205 ATTRIBUTE_GROUPS(dbc_dev);
1206 
1207 struct xhci_dbc *
1208 xhci_alloc_dbc(struct device *dev, void __iomem *base, const struct dbc_driver *driver)
1209 {
1210 	struct xhci_dbc		*dbc;
1211 	int			ret;
1212 
1213 	dbc = kzalloc(sizeof(*dbc), GFP_KERNEL);
1214 	if (!dbc)
1215 		return NULL;
1216 
1217 	dbc->regs = base;
1218 	dbc->dev = dev;
1219 	dbc->driver = driver;
1220 	dbc->idProduct = DBC_PRODUCT_ID;
1221 	dbc->idVendor = DBC_VENDOR_ID;
1222 	dbc->bcdDevice = DBC_DEVICE_REV;
1223 	dbc->bInterfaceProtocol = DBC_PROTOCOL;
1224 	dbc->poll_interval = DBC_POLL_INTERVAL_DEFAULT;
1225 
1226 	if (readl(&dbc->regs->control) & DBC_CTRL_DBC_ENABLE)
1227 		goto err;
1228 
1229 	INIT_DELAYED_WORK(&dbc->event_work, xhci_dbc_handle_events);
1230 	spin_lock_init(&dbc->lock);
1231 
1232 	ret = sysfs_create_groups(&dev->kobj, dbc_dev_groups);
1233 	if (ret)
1234 		goto err;
1235 
1236 	return dbc;
1237 err:
1238 	kfree(dbc);
1239 	return NULL;
1240 }
1241 
1242 /* undo what xhci_alloc_dbc() did */
1243 void xhci_dbc_remove(struct xhci_dbc *dbc)
1244 {
1245 	if (!dbc)
1246 		return;
1247 	/* stop hw, stop wq and call dbc->ops->stop() */
1248 	xhci_dbc_stop(dbc);
1249 
1250 	/* remove sysfs files */
1251 	sysfs_remove_groups(&dbc->dev->kobj, dbc_dev_groups);
1252 
1253 	kfree(dbc);
1254 }
1255 
1256 
1257 int xhci_create_dbc_dev(struct xhci_hcd *xhci)
1258 {
1259 	struct device		*dev;
1260 	void __iomem		*base;
1261 	int			ret;
1262 	int			dbc_cap_offs;
1263 
1264 	/* create all parameters needed resembling a dbc device */
1265 	dev = xhci_to_hcd(xhci)->self.controller;
1266 	base = &xhci->cap_regs->hc_capbase;
1267 
1268 	dbc_cap_offs = xhci_find_next_ext_cap(base, 0, XHCI_EXT_CAPS_DEBUG);
1269 	if (!dbc_cap_offs)
1270 		return -ENODEV;
1271 
1272 	/* already allocated and in use */
1273 	if (xhci->dbc)
1274 		return -EBUSY;
1275 
1276 	ret = xhci_dbc_tty_probe(dev, base + dbc_cap_offs, xhci);
1277 
1278 	return ret;
1279 }
1280 
1281 void xhci_remove_dbc_dev(struct xhci_hcd *xhci)
1282 {
1283 	unsigned long		flags;
1284 
1285 	if (!xhci->dbc)
1286 		return;
1287 
1288 	xhci_dbc_tty_remove(xhci->dbc);
1289 	spin_lock_irqsave(&xhci->lock, flags);
1290 	xhci->dbc = NULL;
1291 	spin_unlock_irqrestore(&xhci->lock, flags);
1292 }
1293 
1294 #ifdef CONFIG_PM
1295 int xhci_dbc_suspend(struct xhci_hcd *xhci)
1296 {
1297 	struct xhci_dbc		*dbc = xhci->dbc;
1298 
1299 	if (!dbc)
1300 		return 0;
1301 
1302 	if (dbc->state == DS_CONFIGURED)
1303 		dbc->resume_required = 1;
1304 
1305 	xhci_dbc_stop(dbc);
1306 
1307 	return 0;
1308 }
1309 
1310 int xhci_dbc_resume(struct xhci_hcd *xhci)
1311 {
1312 	int			ret = 0;
1313 	struct xhci_dbc		*dbc = xhci->dbc;
1314 
1315 	if (!dbc)
1316 		return 0;
1317 
1318 	if (dbc->resume_required) {
1319 		dbc->resume_required = 0;
1320 		xhci_dbc_start(dbc);
1321 	}
1322 
1323 	return ret;
1324 }
1325 #endif /* CONFIG_PM */
1326 
1327 int xhci_dbc_init(void)
1328 {
1329 	return dbc_tty_init();
1330 }
1331 
1332 void xhci_dbc_exit(void)
1333 {
1334 	dbc_tty_exit();
1335 }
1336