xref: /openbmc/linux/drivers/usb/host/xhci-dbgcap.c (revision d9fd5a71)
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/dma-mapping.h>
10 #include <linux/slab.h>
11 #include <linux/nls.h>
12 
13 #include "xhci.h"
14 #include "xhci-trace.h"
15 #include "xhci-dbgcap.h"
16 
17 static void dbc_free_ctx(struct device *dev, struct xhci_container_ctx *ctx)
18 {
19 	if (!ctx)
20 		return;
21 	dma_free_coherent(dev, ctx->size, ctx->bytes, ctx->dma);
22 	kfree(ctx);
23 }
24 
25 /* we use only one segment for DbC rings */
26 static void dbc_ring_free(struct device *dev, struct xhci_ring *ring)
27 {
28 	if (!ring)
29 		return;
30 
31 	if (ring->first_seg && ring->first_seg->trbs) {
32 		dma_free_coherent(dev, TRB_SEGMENT_SIZE,
33 				  ring->first_seg->trbs,
34 				  ring->first_seg->dma);
35 		kfree(ring->first_seg);
36 	}
37 	kfree(ring);
38 }
39 
40 static u32 xhci_dbc_populate_strings(struct dbc_str_descs *strings)
41 {
42 	struct usb_string_descriptor	*s_desc;
43 	u32				string_length;
44 
45 	/* Serial string: */
46 	s_desc = (struct usb_string_descriptor *)strings->serial;
47 	utf8s_to_utf16s(DBC_STRING_SERIAL, strlen(DBC_STRING_SERIAL),
48 			UTF16_LITTLE_ENDIAN, (wchar_t *)s_desc->wData,
49 			DBC_MAX_STRING_LENGTH);
50 
51 	s_desc->bLength		= (strlen(DBC_STRING_SERIAL) + 1) * 2;
52 	s_desc->bDescriptorType	= USB_DT_STRING;
53 	string_length		= s_desc->bLength;
54 	string_length		<<= 8;
55 
56 	/* Product string: */
57 	s_desc = (struct usb_string_descriptor *)strings->product;
58 	utf8s_to_utf16s(DBC_STRING_PRODUCT, strlen(DBC_STRING_PRODUCT),
59 			UTF16_LITTLE_ENDIAN, (wchar_t *)s_desc->wData,
60 			DBC_MAX_STRING_LENGTH);
61 
62 	s_desc->bLength		= (strlen(DBC_STRING_PRODUCT) + 1) * 2;
63 	s_desc->bDescriptorType	= USB_DT_STRING;
64 	string_length		+= s_desc->bLength;
65 	string_length		<<= 8;
66 
67 	/* Manufacture string: */
68 	s_desc = (struct usb_string_descriptor *)strings->manufacturer;
69 	utf8s_to_utf16s(DBC_STRING_MANUFACTURER,
70 			strlen(DBC_STRING_MANUFACTURER),
71 			UTF16_LITTLE_ENDIAN, (wchar_t *)s_desc->wData,
72 			DBC_MAX_STRING_LENGTH);
73 
74 	s_desc->bLength		= (strlen(DBC_STRING_MANUFACTURER) + 1) * 2;
75 	s_desc->bDescriptorType	= USB_DT_STRING;
76 	string_length		+= s_desc->bLength;
77 	string_length		<<= 8;
78 
79 	/* String0: */
80 	strings->string0[0]	= 4;
81 	strings->string0[1]	= USB_DT_STRING;
82 	strings->string0[2]	= 0x09;
83 	strings->string0[3]	= 0x04;
84 	string_length		+= 4;
85 
86 	return string_length;
87 }
88 
89 static void xhci_dbc_init_contexts(struct xhci_dbc *dbc, u32 string_length)
90 {
91 	struct dbc_info_context	*info;
92 	struct xhci_ep_ctx	*ep_ctx;
93 	u32			dev_info;
94 	dma_addr_t		deq, dma;
95 	unsigned int		max_burst;
96 
97 	if (!dbc)
98 		return;
99 
100 	/* Populate info Context: */
101 	info			= (struct dbc_info_context *)dbc->ctx->bytes;
102 	dma			= dbc->string_dma;
103 	info->string0		= cpu_to_le64(dma);
104 	info->manufacturer	= cpu_to_le64(dma + DBC_MAX_STRING_LENGTH);
105 	info->product		= cpu_to_le64(dma + DBC_MAX_STRING_LENGTH * 2);
106 	info->serial		= cpu_to_le64(dma + DBC_MAX_STRING_LENGTH * 3);
107 	info->length		= cpu_to_le32(string_length);
108 
109 	/* Populate bulk out endpoint context: */
110 	ep_ctx			= dbc_bulkout_ctx(dbc);
111 	max_burst		= DBC_CTRL_MAXBURST(readl(&dbc->regs->control));
112 	deq			= dbc_bulkout_enq(dbc);
113 	ep_ctx->ep_info		= 0;
114 	ep_ctx->ep_info2	= dbc_epctx_info2(BULK_OUT_EP, 1024, max_burst);
115 	ep_ctx->deq		= cpu_to_le64(deq | dbc->ring_out->cycle_state);
116 
117 	/* Populate bulk in endpoint context: */
118 	ep_ctx			= dbc_bulkin_ctx(dbc);
119 	deq			= dbc_bulkin_enq(dbc);
120 	ep_ctx->ep_info		= 0;
121 	ep_ctx->ep_info2	= dbc_epctx_info2(BULK_IN_EP, 1024, max_burst);
122 	ep_ctx->deq		= cpu_to_le64(deq | dbc->ring_in->cycle_state);
123 
124 	/* Set DbC context and info registers: */
125 	lo_hi_writeq(dbc->ctx->dma, &dbc->regs->dccp);
126 
127 	dev_info = cpu_to_le32((DBC_VENDOR_ID << 16) | DBC_PROTOCOL);
128 	writel(dev_info, &dbc->regs->devinfo1);
129 
130 	dev_info = cpu_to_le32((DBC_DEVICE_REV << 16) | DBC_PRODUCT_ID);
131 	writel(dev_info, &dbc->regs->devinfo2);
132 }
133 
134 static void xhci_dbc_giveback(struct dbc_request *req, int status)
135 	__releases(&dbc->lock)
136 	__acquires(&dbc->lock)
137 {
138 	struct xhci_dbc		*dbc = req->dbc;
139 	struct device		*dev = dbc->dev;
140 
141 	list_del_init(&req->list_pending);
142 	req->trb_dma = 0;
143 	req->trb = NULL;
144 
145 	if (req->status == -EINPROGRESS)
146 		req->status = status;
147 
148 	trace_xhci_dbc_giveback_request(req);
149 
150 	dma_unmap_single(dev,
151 			 req->dma,
152 			 req->length,
153 			 dbc_ep_dma_direction(req));
154 
155 	/* Give back the transfer request: */
156 	spin_unlock(&dbc->lock);
157 	req->complete(dbc, req);
158 	spin_lock(&dbc->lock);
159 }
160 
161 static void xhci_dbc_flush_single_request(struct dbc_request *req)
162 {
163 	union xhci_trb	*trb = req->trb;
164 
165 	trb->generic.field[0]	= 0;
166 	trb->generic.field[1]	= 0;
167 	trb->generic.field[2]	= 0;
168 	trb->generic.field[3]	&= cpu_to_le32(TRB_CYCLE);
169 	trb->generic.field[3]	|= cpu_to_le32(TRB_TYPE(TRB_TR_NOOP));
170 
171 	xhci_dbc_giveback(req, -ESHUTDOWN);
172 }
173 
174 static void xhci_dbc_flush_endpoint_requests(struct dbc_ep *dep)
175 {
176 	struct dbc_request	*req, *tmp;
177 
178 	list_for_each_entry_safe(req, tmp, &dep->list_pending, list_pending)
179 		xhci_dbc_flush_single_request(req);
180 }
181 
182 static void xhci_dbc_flush_requests(struct xhci_dbc *dbc)
183 {
184 	xhci_dbc_flush_endpoint_requests(&dbc->eps[BULK_OUT]);
185 	xhci_dbc_flush_endpoint_requests(&dbc->eps[BULK_IN]);
186 }
187 
188 struct dbc_request *
189 dbc_alloc_request(struct xhci_dbc *dbc, unsigned int direction, gfp_t flags)
190 {
191 	struct dbc_request	*req;
192 
193 	if (direction != BULK_IN &&
194 	    direction != BULK_OUT)
195 		return NULL;
196 
197 	if (!dbc)
198 		return NULL;
199 
200 	req = kzalloc(sizeof(*req), flags);
201 	if (!req)
202 		return NULL;
203 
204 	req->dbc = dbc;
205 	INIT_LIST_HEAD(&req->list_pending);
206 	INIT_LIST_HEAD(&req->list_pool);
207 	req->direction = direction;
208 
209 	trace_xhci_dbc_alloc_request(req);
210 
211 	return req;
212 }
213 
214 void
215 dbc_free_request(struct dbc_request *req)
216 {
217 	trace_xhci_dbc_free_request(req);
218 
219 	kfree(req);
220 }
221 
222 static void
223 xhci_dbc_queue_trb(struct xhci_ring *ring, u32 field1,
224 		   u32 field2, u32 field3, u32 field4)
225 {
226 	union xhci_trb		*trb, *next;
227 
228 	trb = ring->enqueue;
229 	trb->generic.field[0]	= cpu_to_le32(field1);
230 	trb->generic.field[1]	= cpu_to_le32(field2);
231 	trb->generic.field[2]	= cpu_to_le32(field3);
232 	trb->generic.field[3]	= cpu_to_le32(field4);
233 
234 	trace_xhci_dbc_gadget_ep_queue(ring, &trb->generic);
235 
236 	ring->num_trbs_free--;
237 	next = ++(ring->enqueue);
238 	if (TRB_TYPE_LINK_LE32(next->link.control)) {
239 		next->link.control ^= cpu_to_le32(TRB_CYCLE);
240 		ring->enqueue = ring->enq_seg->trbs;
241 		ring->cycle_state ^= 1;
242 	}
243 }
244 
245 static int xhci_dbc_queue_bulk_tx(struct dbc_ep *dep,
246 				  struct dbc_request *req)
247 {
248 	u64			addr;
249 	union xhci_trb		*trb;
250 	unsigned int		num_trbs;
251 	struct xhci_dbc		*dbc = req->dbc;
252 	struct xhci_ring	*ring = dep->ring;
253 	u32			length, control, cycle;
254 
255 	num_trbs = count_trbs(req->dma, req->length);
256 	WARN_ON(num_trbs != 1);
257 	if (ring->num_trbs_free < num_trbs)
258 		return -EBUSY;
259 
260 	addr	= req->dma;
261 	trb	= ring->enqueue;
262 	cycle	= ring->cycle_state;
263 	length	= TRB_LEN(req->length);
264 	control	= TRB_TYPE(TRB_NORMAL) | TRB_IOC;
265 
266 	if (cycle)
267 		control &= cpu_to_le32(~TRB_CYCLE);
268 	else
269 		control |= cpu_to_le32(TRB_CYCLE);
270 
271 	req->trb = ring->enqueue;
272 	req->trb_dma = xhci_trb_virt_to_dma(ring->enq_seg, ring->enqueue);
273 	xhci_dbc_queue_trb(ring,
274 			   lower_32_bits(addr),
275 			   upper_32_bits(addr),
276 			   length, control);
277 
278 	/*
279 	 * Add a barrier between writes of trb fields and flipping
280 	 * the cycle bit:
281 	 */
282 	wmb();
283 
284 	if (cycle)
285 		trb->generic.field[3] |= cpu_to_le32(TRB_CYCLE);
286 	else
287 		trb->generic.field[3] &= cpu_to_le32(~TRB_CYCLE);
288 
289 	writel(DBC_DOOR_BELL_TARGET(dep->direction), &dbc->regs->doorbell);
290 
291 	return 0;
292 }
293 
294 static int
295 dbc_ep_do_queue(struct dbc_request *req)
296 {
297 	int			ret;
298 	struct xhci_dbc		*dbc = req->dbc;
299 	struct device		*dev = dbc->dev;
300 	struct dbc_ep		*dep = &dbc->eps[req->direction];
301 
302 	if (!req->length || !req->buf)
303 		return -EINVAL;
304 
305 	req->actual		= 0;
306 	req->status		= -EINPROGRESS;
307 
308 	req->dma = dma_map_single(dev,
309 				  req->buf,
310 				  req->length,
311 				  dbc_ep_dma_direction(dep));
312 	if (dma_mapping_error(dev, req->dma)) {
313 		dev_err(dbc->dev, "failed to map buffer\n");
314 		return -EFAULT;
315 	}
316 
317 	ret = xhci_dbc_queue_bulk_tx(dep, req);
318 	if (ret) {
319 		dev_err(dbc->dev, "failed to queue trbs\n");
320 		dma_unmap_single(dev,
321 				 req->dma,
322 				 req->length,
323 				 dbc_ep_dma_direction(dep));
324 		return -EFAULT;
325 	}
326 
327 	list_add_tail(&req->list_pending, &dep->list_pending);
328 
329 	return 0;
330 }
331 
332 int dbc_ep_queue(struct dbc_request *req)
333 {
334 	unsigned long		flags;
335 	struct xhci_dbc		*dbc = req->dbc;
336 	int			ret = -ESHUTDOWN;
337 
338 	if (!dbc)
339 		return -ENODEV;
340 
341 	if (req->direction != BULK_IN &&
342 	    req->direction != BULK_OUT)
343 		return -EINVAL;
344 
345 	spin_lock_irqsave(&dbc->lock, flags);
346 	if (dbc->state == DS_CONFIGURED)
347 		ret = dbc_ep_do_queue(req);
348 	spin_unlock_irqrestore(&dbc->lock, flags);
349 
350 	mod_delayed_work(system_wq, &dbc->event_work, 0);
351 
352 	trace_xhci_dbc_queue_request(req);
353 
354 	return ret;
355 }
356 
357 static inline void xhci_dbc_do_eps_init(struct xhci_dbc *dbc, bool direction)
358 {
359 	struct dbc_ep		*dep;
360 
361 	dep			= &dbc->eps[direction];
362 	dep->dbc		= dbc;
363 	dep->direction		= direction;
364 	dep->ring		= direction ? dbc->ring_in : dbc->ring_out;
365 
366 	INIT_LIST_HEAD(&dep->list_pending);
367 }
368 
369 static void xhci_dbc_eps_init(struct xhci_dbc *dbc)
370 {
371 	xhci_dbc_do_eps_init(dbc, BULK_OUT);
372 	xhci_dbc_do_eps_init(dbc, BULK_IN);
373 }
374 
375 static void xhci_dbc_eps_exit(struct xhci_dbc *dbc)
376 {
377 	memset(dbc->eps, 0, sizeof(struct dbc_ep) * ARRAY_SIZE(dbc->eps));
378 }
379 
380 static int dbc_erst_alloc(struct device *dev, struct xhci_ring *evt_ring,
381 		    struct xhci_erst *erst, gfp_t flags)
382 {
383 	erst->entries = dma_alloc_coherent(dev, sizeof(struct xhci_erst_entry),
384 					   &erst->erst_dma_addr, flags);
385 	if (!erst->entries)
386 		return -ENOMEM;
387 
388 	erst->num_entries = 1;
389 	erst->entries[0].seg_addr = cpu_to_le64(evt_ring->first_seg->dma);
390 	erst->entries[0].seg_size = cpu_to_le32(TRBS_PER_SEGMENT);
391 	erst->entries[0].rsvd = 0;
392 	return 0;
393 }
394 
395 static void dbc_erst_free(struct device *dev, struct xhci_erst *erst)
396 {
397 	if (erst->entries)
398 		dma_free_coherent(dev, sizeof(struct xhci_erst_entry),
399 				  erst->entries, erst->erst_dma_addr);
400 	erst->entries = NULL;
401 }
402 
403 static struct xhci_container_ctx *
404 dbc_alloc_ctx(struct device *dev, gfp_t flags)
405 {
406 	struct xhci_container_ctx *ctx;
407 
408 	ctx = kzalloc(sizeof(*ctx), flags);
409 	if (!ctx)
410 		return NULL;
411 
412 	/* xhci 7.6.9, all three contexts; info, ep-out and ep-in. Each 64 bytes*/
413 	ctx->size = 3 * DBC_CONTEXT_SIZE;
414 	ctx->bytes = dma_alloc_coherent(dev, ctx->size, &ctx->dma, flags);
415 	if (!ctx->bytes) {
416 		kfree(ctx);
417 		return NULL;
418 	}
419 	return ctx;
420 }
421 
422 static struct xhci_ring *
423 xhci_dbc_ring_alloc(struct device *dev, enum xhci_ring_type type, gfp_t flags)
424 {
425 	struct xhci_ring *ring;
426 	struct xhci_segment *seg;
427 	dma_addr_t dma;
428 
429 	ring = kzalloc(sizeof(*ring), flags);
430 	if (!ring)
431 		return NULL;
432 
433 	ring->num_segs = 1;
434 	ring->type = type;
435 
436 	seg = kzalloc(sizeof(*seg), flags);
437 	if (!seg)
438 		goto seg_fail;
439 
440 	ring->first_seg = seg;
441 	ring->last_seg = seg;
442 	seg->next = seg;
443 
444 	seg->trbs = dma_alloc_coherent(dev, TRB_SEGMENT_SIZE, &dma, flags);
445 	if (!seg->trbs)
446 		goto dma_fail;
447 
448 	seg->dma = dma;
449 
450 	/* Only event ring does not use link TRB */
451 	if (type != TYPE_EVENT) {
452 		union xhci_trb *trb = &seg->trbs[TRBS_PER_SEGMENT - 1];
453 
454 		trb->link.segment_ptr = cpu_to_le64(dma);
455 		trb->link.control = cpu_to_le32(LINK_TOGGLE | TRB_TYPE(TRB_LINK));
456 	}
457 	INIT_LIST_HEAD(&ring->td_list);
458 	xhci_initialize_ring_info(ring, 1);
459 	return ring;
460 dma_fail:
461 	kfree(seg);
462 seg_fail:
463 	kfree(ring);
464 	return NULL;
465 }
466 
467 static int xhci_dbc_mem_init(struct xhci_dbc *dbc, gfp_t flags)
468 {
469 	int			ret;
470 	dma_addr_t		deq;
471 	u32			string_length;
472 	struct device		*dev = dbc->dev;
473 
474 	/* Allocate various rings for events and transfers: */
475 	dbc->ring_evt = xhci_dbc_ring_alloc(dev, TYPE_EVENT, flags);
476 	if (!dbc->ring_evt)
477 		goto evt_fail;
478 
479 	dbc->ring_in = xhci_dbc_ring_alloc(dev, TYPE_BULK, flags);
480 	if (!dbc->ring_in)
481 		goto in_fail;
482 
483 	dbc->ring_out = xhci_dbc_ring_alloc(dev, TYPE_BULK, flags);
484 	if (!dbc->ring_out)
485 		goto out_fail;
486 
487 	/* Allocate and populate ERST: */
488 	ret = dbc_erst_alloc(dev, dbc->ring_evt, &dbc->erst, flags);
489 	if (ret)
490 		goto erst_fail;
491 
492 	/* Allocate context data structure: */
493 	dbc->ctx = dbc_alloc_ctx(dev, flags); /* was sysdev, and is still */
494 	if (!dbc->ctx)
495 		goto ctx_fail;
496 
497 	/* Allocate the string table: */
498 	dbc->string_size = sizeof(struct dbc_str_descs);
499 	dbc->string = dma_alloc_coherent(dev, dbc->string_size,
500 					 &dbc->string_dma, flags);
501 	if (!dbc->string)
502 		goto string_fail;
503 
504 	/* Setup ERST register: */
505 	writel(dbc->erst.erst_size, &dbc->regs->ersts);
506 
507 	lo_hi_writeq(dbc->erst.erst_dma_addr, &dbc->regs->erstba);
508 	deq = xhci_trb_virt_to_dma(dbc->ring_evt->deq_seg,
509 				   dbc->ring_evt->dequeue);
510 	lo_hi_writeq(deq, &dbc->regs->erdp);
511 
512 	/* Setup strings and contexts: */
513 	string_length = xhci_dbc_populate_strings(dbc->string);
514 	xhci_dbc_init_contexts(dbc, string_length);
515 
516 	xhci_dbc_eps_init(dbc);
517 	dbc->state = DS_INITIALIZED;
518 
519 	return 0;
520 
521 string_fail:
522 	dbc_free_ctx(dev, dbc->ctx);
523 	dbc->ctx = NULL;
524 ctx_fail:
525 	dbc_erst_free(dev, &dbc->erst);
526 erst_fail:
527 	dbc_ring_free(dev, dbc->ring_out);
528 	dbc->ring_out = NULL;
529 out_fail:
530 	dbc_ring_free(dev, dbc->ring_in);
531 	dbc->ring_in = NULL;
532 in_fail:
533 	dbc_ring_free(dev, dbc->ring_evt);
534 	dbc->ring_evt = NULL;
535 evt_fail:
536 	return -ENOMEM;
537 }
538 
539 static void xhci_dbc_mem_cleanup(struct xhci_dbc *dbc)
540 {
541 	if (!dbc)
542 		return;
543 
544 	xhci_dbc_eps_exit(dbc);
545 
546 	if (dbc->string) {
547 		dma_free_coherent(dbc->dev, dbc->string_size,
548 				  dbc->string, dbc->string_dma);
549 		dbc->string = NULL;
550 	}
551 
552 	dbc_free_ctx(dbc->dev, dbc->ctx);
553 	dbc->ctx = NULL;
554 
555 	dbc_erst_free(dbc->dev, &dbc->erst);
556 	dbc_ring_free(dbc->dev, dbc->ring_out);
557 	dbc_ring_free(dbc->dev, dbc->ring_in);
558 	dbc_ring_free(dbc->dev, dbc->ring_evt);
559 	dbc->ring_in = NULL;
560 	dbc->ring_out = NULL;
561 	dbc->ring_evt = NULL;
562 }
563 
564 static int xhci_do_dbc_start(struct xhci_dbc *dbc)
565 {
566 	int			ret;
567 	u32			ctrl;
568 
569 	if (dbc->state != DS_DISABLED)
570 		return -EINVAL;
571 
572 	writel(0, &dbc->regs->control);
573 	ret = xhci_handshake(&dbc->regs->control,
574 			     DBC_CTRL_DBC_ENABLE,
575 			     0, 1000);
576 	if (ret)
577 		return ret;
578 
579 	ret = xhci_dbc_mem_init(dbc, GFP_ATOMIC);
580 	if (ret)
581 		return ret;
582 
583 	ctrl = readl(&dbc->regs->control);
584 	writel(ctrl | DBC_CTRL_DBC_ENABLE | DBC_CTRL_PORT_ENABLE,
585 	       &dbc->regs->control);
586 	ret = xhci_handshake(&dbc->regs->control,
587 			     DBC_CTRL_DBC_ENABLE,
588 			     DBC_CTRL_DBC_ENABLE, 1000);
589 	if (ret)
590 		return ret;
591 
592 	dbc->state = DS_ENABLED;
593 
594 	return 0;
595 }
596 
597 static int xhci_do_dbc_stop(struct xhci_dbc *dbc)
598 {
599 	if (dbc->state == DS_DISABLED)
600 		return -1;
601 
602 	writel(0, &dbc->regs->control);
603 	dbc->state = DS_DISABLED;
604 
605 	return 0;
606 }
607 
608 static int xhci_dbc_start(struct xhci_dbc *dbc)
609 {
610 	int			ret;
611 	unsigned long		flags;
612 
613 	WARN_ON(!dbc);
614 
615 	pm_runtime_get_sync(dbc->dev); /* note this was self.controller */
616 
617 	spin_lock_irqsave(&dbc->lock, flags);
618 	ret = xhci_do_dbc_start(dbc);
619 	spin_unlock_irqrestore(&dbc->lock, flags);
620 
621 	if (ret) {
622 		pm_runtime_put(dbc->dev); /* note this was self.controller */
623 		return ret;
624 	}
625 
626 	return mod_delayed_work(system_wq, &dbc->event_work, 1);
627 }
628 
629 static void xhci_dbc_stop(struct xhci_dbc *dbc)
630 {
631 	int ret;
632 	unsigned long		flags;
633 
634 	WARN_ON(!dbc);
635 
636 	switch (dbc->state) {
637 	case DS_DISABLED:
638 		return;
639 	case DS_CONFIGURED:
640 	case DS_STALLED:
641 		if (dbc->driver->disconnect)
642 			dbc->driver->disconnect(dbc);
643 		break;
644 	default:
645 		break;
646 	}
647 
648 	cancel_delayed_work_sync(&dbc->event_work);
649 
650 	spin_lock_irqsave(&dbc->lock, flags);
651 	ret = xhci_do_dbc_stop(dbc);
652 	spin_unlock_irqrestore(&dbc->lock, flags);
653 
654 	if (!ret) {
655 		xhci_dbc_mem_cleanup(dbc);
656 		pm_runtime_put_sync(dbc->dev); /* note, was self.controller */
657 	}
658 }
659 
660 static void
661 dbc_handle_port_status(struct xhci_dbc *dbc, union xhci_trb *event)
662 {
663 	u32			portsc;
664 
665 	portsc = readl(&dbc->regs->portsc);
666 	if (portsc & DBC_PORTSC_CONN_CHANGE)
667 		dev_info(dbc->dev, "DbC port connect change\n");
668 
669 	if (portsc & DBC_PORTSC_RESET_CHANGE)
670 		dev_info(dbc->dev, "DbC port reset change\n");
671 
672 	if (portsc & DBC_PORTSC_LINK_CHANGE)
673 		dev_info(dbc->dev, "DbC port link status change\n");
674 
675 	if (portsc & DBC_PORTSC_CONFIG_CHANGE)
676 		dev_info(dbc->dev, "DbC config error change\n");
677 
678 	/* Port reset change bit will be cleared in other place: */
679 	writel(portsc & ~DBC_PORTSC_RESET_CHANGE, &dbc->regs->portsc);
680 }
681 
682 static void dbc_handle_xfer_event(struct xhci_dbc *dbc, union xhci_trb *event)
683 {
684 	struct dbc_ep		*dep;
685 	struct xhci_ring	*ring;
686 	int			ep_id;
687 	int			status;
688 	u32			comp_code;
689 	size_t			remain_length;
690 	struct dbc_request	*req = NULL, *r;
691 
692 	comp_code	= GET_COMP_CODE(le32_to_cpu(event->generic.field[2]));
693 	remain_length	= EVENT_TRB_LEN(le32_to_cpu(event->generic.field[2]));
694 	ep_id		= TRB_TO_EP_ID(le32_to_cpu(event->generic.field[3]));
695 	dep		= (ep_id == EPID_OUT) ?
696 				get_out_ep(dbc) : get_in_ep(dbc);
697 	ring		= dep->ring;
698 
699 	switch (comp_code) {
700 	case COMP_SUCCESS:
701 		remain_length = 0;
702 		fallthrough;
703 	case COMP_SHORT_PACKET:
704 		status = 0;
705 		break;
706 	case COMP_TRB_ERROR:
707 	case COMP_BABBLE_DETECTED_ERROR:
708 	case COMP_USB_TRANSACTION_ERROR:
709 	case COMP_STALL_ERROR:
710 		dev_warn(dbc->dev, "tx error %d detected\n", comp_code);
711 		status = -comp_code;
712 		break;
713 	default:
714 		dev_err(dbc->dev, "unknown tx error %d\n", comp_code);
715 		status = -comp_code;
716 		break;
717 	}
718 
719 	/* Match the pending request: */
720 	list_for_each_entry(r, &dep->list_pending, list_pending) {
721 		if (r->trb_dma == event->trans_event.buffer) {
722 			req = r;
723 			break;
724 		}
725 	}
726 
727 	if (!req) {
728 		dev_warn(dbc->dev, "no matched request\n");
729 		return;
730 	}
731 
732 	trace_xhci_dbc_handle_transfer(ring, &req->trb->generic);
733 
734 	ring->num_trbs_free++;
735 	req->actual = req->length - remain_length;
736 	xhci_dbc_giveback(req, status);
737 }
738 
739 static void inc_evt_deq(struct xhci_ring *ring)
740 {
741 	/* If on the last TRB of the segment go back to the beginning */
742 	if (ring->dequeue == &ring->deq_seg->trbs[TRBS_PER_SEGMENT - 1]) {
743 		ring->cycle_state ^= 1;
744 		ring->dequeue = ring->deq_seg->trbs;
745 		return;
746 	}
747 	ring->dequeue++;
748 }
749 
750 static enum evtreturn xhci_dbc_do_handle_events(struct xhci_dbc *dbc)
751 {
752 	dma_addr_t		deq;
753 	struct dbc_ep		*dep;
754 	union xhci_trb		*evt;
755 	u32			ctrl, portsc;
756 	bool			update_erdp = false;
757 
758 	/* DbC state machine: */
759 	switch (dbc->state) {
760 	case DS_DISABLED:
761 	case DS_INITIALIZED:
762 
763 		return EVT_ERR;
764 	case DS_ENABLED:
765 		portsc = readl(&dbc->regs->portsc);
766 		if (portsc & DBC_PORTSC_CONN_STATUS) {
767 			dbc->state = DS_CONNECTED;
768 			dev_info(dbc->dev, "DbC connected\n");
769 		}
770 
771 		return EVT_DONE;
772 	case DS_CONNECTED:
773 		ctrl = readl(&dbc->regs->control);
774 		if (ctrl & DBC_CTRL_DBC_RUN) {
775 			dbc->state = DS_CONFIGURED;
776 			dev_info(dbc->dev, "DbC configured\n");
777 			portsc = readl(&dbc->regs->portsc);
778 			writel(portsc, &dbc->regs->portsc);
779 			return EVT_GSER;
780 		}
781 
782 		return EVT_DONE;
783 	case DS_CONFIGURED:
784 		/* Handle cable unplug event: */
785 		portsc = readl(&dbc->regs->portsc);
786 		if (!(portsc & DBC_PORTSC_PORT_ENABLED) &&
787 		    !(portsc & DBC_PORTSC_CONN_STATUS)) {
788 			dev_info(dbc->dev, "DbC cable unplugged\n");
789 			dbc->state = DS_ENABLED;
790 			xhci_dbc_flush_requests(dbc);
791 
792 			return EVT_DISC;
793 		}
794 
795 		/* Handle debug port reset event: */
796 		if (portsc & DBC_PORTSC_RESET_CHANGE) {
797 			dev_info(dbc->dev, "DbC port reset\n");
798 			writel(portsc, &dbc->regs->portsc);
799 			dbc->state = DS_ENABLED;
800 			xhci_dbc_flush_requests(dbc);
801 
802 			return EVT_DISC;
803 		}
804 
805 		/* Handle endpoint stall event: */
806 		ctrl = readl(&dbc->regs->control);
807 		if ((ctrl & DBC_CTRL_HALT_IN_TR) ||
808 		    (ctrl & DBC_CTRL_HALT_OUT_TR)) {
809 			dev_info(dbc->dev, "DbC Endpoint stall\n");
810 			dbc->state = DS_STALLED;
811 
812 			if (ctrl & DBC_CTRL_HALT_IN_TR) {
813 				dep = get_in_ep(dbc);
814 				xhci_dbc_flush_endpoint_requests(dep);
815 			}
816 
817 			if (ctrl & DBC_CTRL_HALT_OUT_TR) {
818 				dep = get_out_ep(dbc);
819 				xhci_dbc_flush_endpoint_requests(dep);
820 			}
821 
822 			return EVT_DONE;
823 		}
824 
825 		/* Clear DbC run change bit: */
826 		if (ctrl & DBC_CTRL_DBC_RUN_CHANGE) {
827 			writel(ctrl, &dbc->regs->control);
828 			ctrl = readl(&dbc->regs->control);
829 		}
830 
831 		break;
832 	case DS_STALLED:
833 		ctrl = readl(&dbc->regs->control);
834 		if (!(ctrl & DBC_CTRL_HALT_IN_TR) &&
835 		    !(ctrl & DBC_CTRL_HALT_OUT_TR) &&
836 		    (ctrl & DBC_CTRL_DBC_RUN)) {
837 			dbc->state = DS_CONFIGURED;
838 			break;
839 		}
840 
841 		return EVT_DONE;
842 	default:
843 		dev_err(dbc->dev, "Unknown DbC state %d\n", dbc->state);
844 		break;
845 	}
846 
847 	/* Handle the events in the event ring: */
848 	evt = dbc->ring_evt->dequeue;
849 	while ((le32_to_cpu(evt->event_cmd.flags) & TRB_CYCLE) ==
850 			dbc->ring_evt->cycle_state) {
851 		/*
852 		 * Add a barrier between reading the cycle flag and any
853 		 * reads of the event's flags/data below:
854 		 */
855 		rmb();
856 
857 		trace_xhci_dbc_handle_event(dbc->ring_evt, &evt->generic);
858 
859 		switch (le32_to_cpu(evt->event_cmd.flags) & TRB_TYPE_BITMASK) {
860 		case TRB_TYPE(TRB_PORT_STATUS):
861 			dbc_handle_port_status(dbc, evt);
862 			break;
863 		case TRB_TYPE(TRB_TRANSFER):
864 			dbc_handle_xfer_event(dbc, evt);
865 			break;
866 		default:
867 			break;
868 		}
869 
870 		inc_evt_deq(dbc->ring_evt);
871 
872 		evt = dbc->ring_evt->dequeue;
873 		update_erdp = true;
874 	}
875 
876 	/* Update event ring dequeue pointer: */
877 	if (update_erdp) {
878 		deq = xhci_trb_virt_to_dma(dbc->ring_evt->deq_seg,
879 					   dbc->ring_evt->dequeue);
880 		lo_hi_writeq(deq, &dbc->regs->erdp);
881 	}
882 
883 	return EVT_DONE;
884 }
885 
886 static void xhci_dbc_handle_events(struct work_struct *work)
887 {
888 	enum evtreturn		evtr;
889 	struct xhci_dbc		*dbc;
890 	unsigned long		flags;
891 
892 	dbc = container_of(to_delayed_work(work), struct xhci_dbc, event_work);
893 
894 	spin_lock_irqsave(&dbc->lock, flags);
895 	evtr = xhci_dbc_do_handle_events(dbc);
896 	spin_unlock_irqrestore(&dbc->lock, flags);
897 
898 	switch (evtr) {
899 	case EVT_GSER:
900 		if (dbc->driver->configure)
901 			dbc->driver->configure(dbc);
902 		break;
903 	case EVT_DISC:
904 		if (dbc->driver->disconnect)
905 			dbc->driver->disconnect(dbc);
906 		break;
907 	case EVT_DONE:
908 		break;
909 	default:
910 		dev_info(dbc->dev, "stop handling dbc events\n");
911 		return;
912 	}
913 
914 	mod_delayed_work(system_wq, &dbc->event_work, 1);
915 }
916 
917 static void xhci_do_dbc_exit(struct xhci_hcd *xhci)
918 {
919 	unsigned long		flags;
920 
921 	spin_lock_irqsave(&xhci->lock, flags);
922 	kfree(xhci->dbc);
923 	xhci->dbc = NULL;
924 	spin_unlock_irqrestore(&xhci->lock, flags);
925 }
926 
927 static int xhci_do_dbc_init(struct xhci_hcd *xhci)
928 {
929 	u32			reg;
930 	struct xhci_dbc		*dbc;
931 	unsigned long		flags;
932 	void __iomem		*base;
933 	int			dbc_cap_offs;
934 
935 	base = &xhci->cap_regs->hc_capbase;
936 	dbc_cap_offs = xhci_find_next_ext_cap(base, 0, XHCI_EXT_CAPS_DEBUG);
937 	if (!dbc_cap_offs)
938 		return -ENODEV;
939 
940 	dbc = kzalloc(sizeof(*dbc), GFP_KERNEL);
941 	if (!dbc)
942 		return -ENOMEM;
943 
944 	dbc->regs = base + dbc_cap_offs;
945 
946 	/* We will avoid using DbC in xhci driver if it's in use. */
947 	reg = readl(&dbc->regs->control);
948 	if (reg & DBC_CTRL_DBC_ENABLE) {
949 		kfree(dbc);
950 		return -EBUSY;
951 	}
952 
953 	spin_lock_irqsave(&xhci->lock, flags);
954 	if (xhci->dbc) {
955 		spin_unlock_irqrestore(&xhci->lock, flags);
956 		kfree(dbc);
957 		return -EBUSY;
958 	}
959 	xhci->dbc = dbc;
960 	spin_unlock_irqrestore(&xhci->lock, flags);
961 
962 	dbc->xhci = xhci;
963 	dbc->dev = xhci_to_hcd(xhci)->self.sysdev;
964 	INIT_DELAYED_WORK(&dbc->event_work, xhci_dbc_handle_events);
965 	spin_lock_init(&dbc->lock);
966 
967 	return 0;
968 }
969 
970 static ssize_t dbc_show(struct device *dev,
971 			struct device_attribute *attr,
972 			char *buf)
973 {
974 	const char		*p;
975 	struct xhci_dbc		*dbc;
976 	struct xhci_hcd		*xhci;
977 
978 	xhci = hcd_to_xhci(dev_get_drvdata(dev));
979 	dbc = xhci->dbc;
980 
981 	switch (dbc->state) {
982 	case DS_DISABLED:
983 		p = "disabled";
984 		break;
985 	case DS_INITIALIZED:
986 		p = "initialized";
987 		break;
988 	case DS_ENABLED:
989 		p = "enabled";
990 		break;
991 	case DS_CONNECTED:
992 		p = "connected";
993 		break;
994 	case DS_CONFIGURED:
995 		p = "configured";
996 		break;
997 	case DS_STALLED:
998 		p = "stalled";
999 		break;
1000 	default:
1001 		p = "unknown";
1002 	}
1003 
1004 	return sprintf(buf, "%s\n", p);
1005 }
1006 
1007 static ssize_t dbc_store(struct device *dev,
1008 			 struct device_attribute *attr,
1009 			 const char *buf, size_t count)
1010 {
1011 	struct xhci_hcd		*xhci;
1012 	struct xhci_dbc		*dbc;
1013 
1014 	xhci = hcd_to_xhci(dev_get_drvdata(dev));
1015 	dbc = xhci->dbc;
1016 
1017 	if (!strncmp(buf, "enable", 6))
1018 		xhci_dbc_start(dbc);
1019 	else if (!strncmp(buf, "disable", 7))
1020 		xhci_dbc_stop(dbc);
1021 	else
1022 		return -EINVAL;
1023 
1024 	return count;
1025 }
1026 
1027 static DEVICE_ATTR_RW(dbc);
1028 
1029 int xhci_dbc_init(struct xhci_hcd *xhci)
1030 {
1031 	int			ret;
1032 	struct device		*dev = xhci_to_hcd(xhci)->self.controller;
1033 
1034 	ret = xhci_do_dbc_init(xhci);
1035 	if (ret)
1036 		goto init_err3;
1037 
1038 	ret = xhci_dbc_tty_probe(xhci);
1039 	if (ret)
1040 		goto init_err2;
1041 
1042 	ret = device_create_file(dev, &dev_attr_dbc);
1043 	if (ret)
1044 		goto init_err1;
1045 
1046 	return 0;
1047 
1048 init_err1:
1049 	xhci_dbc_tty_remove(xhci->dbc);
1050 init_err2:
1051 	xhci_do_dbc_exit(xhci);
1052 init_err3:
1053 	return ret;
1054 }
1055 
1056 void xhci_dbc_exit(struct xhci_hcd *xhci)
1057 {
1058 	struct device		*dev = xhci_to_hcd(xhci)->self.controller;
1059 
1060 	if (!xhci->dbc)
1061 		return;
1062 
1063 	device_remove_file(dev, &dev_attr_dbc);
1064 	xhci_dbc_tty_remove(xhci->dbc);
1065 	xhci_dbc_stop(xhci->dbc);
1066 	xhci_do_dbc_exit(xhci);
1067 }
1068 
1069 #ifdef CONFIG_PM
1070 int xhci_dbc_suspend(struct xhci_hcd *xhci)
1071 {
1072 	struct xhci_dbc		*dbc = xhci->dbc;
1073 
1074 	if (!dbc)
1075 		return 0;
1076 
1077 	if (dbc->state == DS_CONFIGURED)
1078 		dbc->resume_required = 1;
1079 
1080 	xhci_dbc_stop(dbc);
1081 
1082 	return 0;
1083 }
1084 
1085 int xhci_dbc_resume(struct xhci_hcd *xhci)
1086 {
1087 	int			ret = 0;
1088 	struct xhci_dbc		*dbc = xhci->dbc;
1089 
1090 	if (!dbc)
1091 		return 0;
1092 
1093 	if (dbc->resume_required) {
1094 		dbc->resume_required = 0;
1095 		xhci_dbc_start(dbc);
1096 	}
1097 
1098 	return ret;
1099 }
1100 #endif /* CONFIG_PM */
1101