xref: /linux/drivers/usb/host/xhci-ring.c (revision a234ca0faa65dcd5cc473915bd925130ebb7b74b)
1 /*
2  * xHCI host controller driver
3  *
4  * Copyright (C) 2008 Intel Corp.
5  *
6  * Author: Sarah Sharp
7  * Some code borrowed from the Linux EHCI driver.
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License version 2 as
11  * published by the Free Software Foundation.
12  *
13  * This program is distributed in the hope that it will be useful, but
14  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
15  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
16  * for more details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this program; if not, write to the Free Software Foundation,
20  * Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21  */
22 
23 /*
24  * Ring initialization rules:
25  * 1. Each segment is initialized to zero, except for link TRBs.
26  * 2. Ring cycle state = 0.  This represents Producer Cycle State (PCS) or
27  *    Consumer Cycle State (CCS), depending on ring function.
28  * 3. Enqueue pointer = dequeue pointer = address of first TRB in the segment.
29  *
30  * Ring behavior rules:
31  * 1. A ring is empty if enqueue == dequeue.  This means there will always be at
32  *    least one free TRB in the ring.  This is useful if you want to turn that
33  *    into a link TRB and expand the ring.
34  * 2. When incrementing an enqueue or dequeue pointer, if the next TRB is a
35  *    link TRB, then load the pointer with the address in the link TRB.  If the
36  *    link TRB had its toggle bit set, you may need to update the ring cycle
37  *    state (see cycle bit rules).  You may have to do this multiple times
38  *    until you reach a non-link TRB.
39  * 3. A ring is full if enqueue++ (for the definition of increment above)
40  *    equals the dequeue pointer.
41  *
42  * Cycle bit rules:
43  * 1. When a consumer increments a dequeue pointer and encounters a toggle bit
44  *    in a link TRB, it must toggle the ring cycle state.
45  * 2. When a producer increments an enqueue pointer and encounters a toggle bit
46  *    in a link TRB, it must toggle the ring cycle state.
47  *
48  * Producer rules:
49  * 1. Check if ring is full before you enqueue.
50  * 2. Write the ring cycle state to the cycle bit in the TRB you're enqueuing.
51  *    Update enqueue pointer between each write (which may update the ring
52  *    cycle state).
53  * 3. Notify consumer.  If SW is producer, it rings the doorbell for command
54  *    and endpoint rings.  If HC is the producer for the event ring,
55  *    and it generates an interrupt according to interrupt modulation rules.
56  *
57  * Consumer rules:
58  * 1. Check if TRB belongs to you.  If the cycle bit == your ring cycle state,
59  *    the TRB is owned by the consumer.
60  * 2. Update dequeue pointer (which may update the ring cycle state) and
61  *    continue processing TRBs until you reach a TRB which is not owned by you.
62  * 3. Notify the producer.  SW is the consumer for the event ring, and it
63  *   updates event ring dequeue pointer.  HC is the consumer for the command and
64  *   endpoint rings; it generates events on the event ring for these.
65  */
66 
67 #include <linux/scatterlist.h>
68 #include <linux/slab.h>
69 #include "xhci.h"
70 
71 /*
72  * Returns zero if the TRB isn't in this segment, otherwise it returns the DMA
73  * address of the TRB.
74  */
75 dma_addr_t xhci_trb_virt_to_dma(struct xhci_segment *seg,
76 		union xhci_trb *trb)
77 {
78 	unsigned long segment_offset;
79 
80 	if (!seg || !trb || trb < seg->trbs)
81 		return 0;
82 	/* offset in TRBs */
83 	segment_offset = trb - seg->trbs;
84 	if (segment_offset > TRBS_PER_SEGMENT)
85 		return 0;
86 	return seg->dma + (segment_offset * sizeof(*trb));
87 }
88 
89 /* Does this link TRB point to the first segment in a ring,
90  * or was the previous TRB the last TRB on the last segment in the ERST?
91  */
92 static inline bool last_trb_on_last_seg(struct xhci_hcd *xhci, struct xhci_ring *ring,
93 		struct xhci_segment *seg, union xhci_trb *trb)
94 {
95 	if (ring == xhci->event_ring)
96 		return (trb == &seg->trbs[TRBS_PER_SEGMENT]) &&
97 			(seg->next == xhci->event_ring->first_seg);
98 	else
99 		return trb->link.control & LINK_TOGGLE;
100 }
101 
102 /* Is this TRB a link TRB or was the last TRB the last TRB in this event ring
103  * segment?  I.e. would the updated event TRB pointer step off the end of the
104  * event seg?
105  */
106 static inline int last_trb(struct xhci_hcd *xhci, struct xhci_ring *ring,
107 		struct xhci_segment *seg, union xhci_trb *trb)
108 {
109 	if (ring == xhci->event_ring)
110 		return trb == &seg->trbs[TRBS_PER_SEGMENT];
111 	else
112 		return (trb->link.control & TRB_TYPE_BITMASK) == TRB_TYPE(TRB_LINK);
113 }
114 
115 static inline int enqueue_is_link_trb(struct xhci_ring *ring)
116 {
117 	struct xhci_link_trb *link = &ring->enqueue->link;
118 	return ((link->control & TRB_TYPE_BITMASK) == TRB_TYPE(TRB_LINK));
119 }
120 
121 /* Updates trb to point to the next TRB in the ring, and updates seg if the next
122  * TRB is in a new segment.  This does not skip over link TRBs, and it does not
123  * effect the ring dequeue or enqueue pointers.
124  */
125 static void next_trb(struct xhci_hcd *xhci,
126 		struct xhci_ring *ring,
127 		struct xhci_segment **seg,
128 		union xhci_trb **trb)
129 {
130 	if (last_trb(xhci, ring, *seg, *trb)) {
131 		*seg = (*seg)->next;
132 		*trb = ((*seg)->trbs);
133 	} else {
134 		*trb = (*trb)++;
135 	}
136 }
137 
138 /*
139  * See Cycle bit rules. SW is the consumer for the event ring only.
140  * Don't make a ring full of link TRBs.  That would be dumb and this would loop.
141  */
142 static void inc_deq(struct xhci_hcd *xhci, struct xhci_ring *ring, bool consumer)
143 {
144 	union xhci_trb *next = ++(ring->dequeue);
145 	unsigned long long addr;
146 
147 	ring->deq_updates++;
148 	/* Update the dequeue pointer further if that was a link TRB or we're at
149 	 * the end of an event ring segment (which doesn't have link TRBS)
150 	 */
151 	while (last_trb(xhci, ring, ring->deq_seg, next)) {
152 		if (consumer && last_trb_on_last_seg(xhci, ring, ring->deq_seg, next)) {
153 			ring->cycle_state = (ring->cycle_state ? 0 : 1);
154 			if (!in_interrupt())
155 				xhci_dbg(xhci, "Toggle cycle state for ring %p = %i\n",
156 						ring,
157 						(unsigned int) ring->cycle_state);
158 		}
159 		ring->deq_seg = ring->deq_seg->next;
160 		ring->dequeue = ring->deq_seg->trbs;
161 		next = ring->dequeue;
162 	}
163 	addr = (unsigned long long) xhci_trb_virt_to_dma(ring->deq_seg, ring->dequeue);
164 	if (ring == xhci->event_ring)
165 		xhci_dbg(xhci, "Event ring deq = 0x%llx (DMA)\n", addr);
166 	else if (ring == xhci->cmd_ring)
167 		xhci_dbg(xhci, "Command ring deq = 0x%llx (DMA)\n", addr);
168 	else
169 		xhci_dbg(xhci, "Ring deq = 0x%llx (DMA)\n", addr);
170 }
171 
172 /*
173  * See Cycle bit rules. SW is the consumer for the event ring only.
174  * Don't make a ring full of link TRBs.  That would be dumb and this would loop.
175  *
176  * If we've just enqueued a TRB that is in the middle of a TD (meaning the
177  * chain bit is set), then set the chain bit in all the following link TRBs.
178  * If we've enqueued the last TRB in a TD, make sure the following link TRBs
179  * have their chain bit cleared (so that each Link TRB is a separate TD).
180  *
181  * Section 6.4.4.1 of the 0.95 spec says link TRBs cannot have the chain bit
182  * set, but other sections talk about dealing with the chain bit set.  This was
183  * fixed in the 0.96 specification errata, but we have to assume that all 0.95
184  * xHCI hardware can't handle the chain bit being cleared on a link TRB.
185  *
186  * @more_trbs_coming:	Will you enqueue more TRBs before calling
187  *			prepare_transfer()?
188  */
189 static void inc_enq(struct xhci_hcd *xhci, struct xhci_ring *ring,
190 		bool consumer, bool more_trbs_coming)
191 {
192 	u32 chain;
193 	union xhci_trb *next;
194 	unsigned long long addr;
195 
196 	chain = ring->enqueue->generic.field[3] & TRB_CHAIN;
197 	next = ++(ring->enqueue);
198 
199 	ring->enq_updates++;
200 	/* Update the dequeue pointer further if that was a link TRB or we're at
201 	 * the end of an event ring segment (which doesn't have link TRBS)
202 	 */
203 	while (last_trb(xhci, ring, ring->enq_seg, next)) {
204 		if (!consumer) {
205 			if (ring != xhci->event_ring) {
206 				/*
207 				 * If the caller doesn't plan on enqueueing more
208 				 * TDs before ringing the doorbell, then we
209 				 * don't want to give the link TRB to the
210 				 * hardware just yet.  We'll give the link TRB
211 				 * back in prepare_ring() just before we enqueue
212 				 * the TD at the top of the ring.
213 				 */
214 				if (!chain && !more_trbs_coming)
215 					break;
216 
217 				/* If we're not dealing with 0.95 hardware,
218 				 * carry over the chain bit of the previous TRB
219 				 * (which may mean the chain bit is cleared).
220 				 */
221 				if (!xhci_link_trb_quirk(xhci)) {
222 					next->link.control &= ~TRB_CHAIN;
223 					next->link.control |= chain;
224 				}
225 				/* Give this link TRB to the hardware */
226 				wmb();
227 				next->link.control ^= TRB_CYCLE;
228 			}
229 			/* Toggle the cycle bit after the last ring segment. */
230 			if (last_trb_on_last_seg(xhci, ring, ring->enq_seg, next)) {
231 				ring->cycle_state = (ring->cycle_state ? 0 : 1);
232 				if (!in_interrupt())
233 					xhci_dbg(xhci, "Toggle cycle state for ring %p = %i\n",
234 							ring,
235 							(unsigned int) ring->cycle_state);
236 			}
237 		}
238 		ring->enq_seg = ring->enq_seg->next;
239 		ring->enqueue = ring->enq_seg->trbs;
240 		next = ring->enqueue;
241 	}
242 	addr = (unsigned long long) xhci_trb_virt_to_dma(ring->enq_seg, ring->enqueue);
243 	if (ring == xhci->event_ring)
244 		xhci_dbg(xhci, "Event ring enq = 0x%llx (DMA)\n", addr);
245 	else if (ring == xhci->cmd_ring)
246 		xhci_dbg(xhci, "Command ring enq = 0x%llx (DMA)\n", addr);
247 	else
248 		xhci_dbg(xhci, "Ring enq = 0x%llx (DMA)\n", addr);
249 }
250 
251 /*
252  * Check to see if there's room to enqueue num_trbs on the ring.  See rules
253  * above.
254  * FIXME: this would be simpler and faster if we just kept track of the number
255  * of free TRBs in a ring.
256  */
257 static int room_on_ring(struct xhci_hcd *xhci, struct xhci_ring *ring,
258 		unsigned int num_trbs)
259 {
260 	int i;
261 	union xhci_trb *enq = ring->enqueue;
262 	struct xhci_segment *enq_seg = ring->enq_seg;
263 	struct xhci_segment *cur_seg;
264 	unsigned int left_on_ring;
265 
266 	/* If we are currently pointing to a link TRB, advance the
267 	 * enqueue pointer before checking for space */
268 	while (last_trb(xhci, ring, enq_seg, enq)) {
269 		enq_seg = enq_seg->next;
270 		enq = enq_seg->trbs;
271 	}
272 
273 	/* Check if ring is empty */
274 	if (enq == ring->dequeue) {
275 		/* Can't use link trbs */
276 		left_on_ring = TRBS_PER_SEGMENT - 1;
277 		for (cur_seg = enq_seg->next; cur_seg != enq_seg;
278 				cur_seg = cur_seg->next)
279 			left_on_ring += TRBS_PER_SEGMENT - 1;
280 
281 		/* Always need one TRB free in the ring. */
282 		left_on_ring -= 1;
283 		if (num_trbs > left_on_ring) {
284 			xhci_warn(xhci, "Not enough room on ring; "
285 					"need %u TRBs, %u TRBs left\n",
286 					num_trbs, left_on_ring);
287 			return 0;
288 		}
289 		return 1;
290 	}
291 	/* Make sure there's an extra empty TRB available */
292 	for (i = 0; i <= num_trbs; ++i) {
293 		if (enq == ring->dequeue)
294 			return 0;
295 		enq++;
296 		while (last_trb(xhci, ring, enq_seg, enq)) {
297 			enq_seg = enq_seg->next;
298 			enq = enq_seg->trbs;
299 		}
300 	}
301 	return 1;
302 }
303 
304 /* Ring the host controller doorbell after placing a command on the ring */
305 void xhci_ring_cmd_db(struct xhci_hcd *xhci)
306 {
307 	u32 temp;
308 
309 	xhci_dbg(xhci, "// Ding dong!\n");
310 	temp = xhci_readl(xhci, &xhci->dba->doorbell[0]) & DB_MASK;
311 	xhci_writel(xhci, temp | DB_TARGET_HOST, &xhci->dba->doorbell[0]);
312 	/* Flush PCI posted writes */
313 	xhci_readl(xhci, &xhci->dba->doorbell[0]);
314 }
315 
316 static void ring_ep_doorbell(struct xhci_hcd *xhci,
317 		unsigned int slot_id,
318 		unsigned int ep_index,
319 		unsigned int stream_id)
320 {
321 	struct xhci_virt_ep *ep;
322 	unsigned int ep_state;
323 	u32 field;
324 	__u32 __iomem *db_addr = &xhci->dba->doorbell[slot_id];
325 
326 	ep = &xhci->devs[slot_id]->eps[ep_index];
327 	ep_state = ep->ep_state;
328 	/* Don't ring the doorbell for this endpoint if there are pending
329 	 * cancellations because the we don't want to interrupt processing.
330 	 * We don't want to restart any stream rings if there's a set dequeue
331 	 * pointer command pending because the device can choose to start any
332 	 * stream once the endpoint is on the HW schedule.
333 	 * FIXME - check all the stream rings for pending cancellations.
334 	 */
335 	if (!(ep_state & EP_HALT_PENDING) && !(ep_state & SET_DEQ_PENDING)
336 			&& !(ep_state & EP_HALTED)) {
337 		field = xhci_readl(xhci, db_addr) & DB_MASK;
338 		field |= EPI_TO_DB(ep_index) | STREAM_ID_TO_DB(stream_id);
339 		xhci_writel(xhci, field, db_addr);
340 	}
341 }
342 
343 /* Ring the doorbell for any rings with pending URBs */
344 static void ring_doorbell_for_active_rings(struct xhci_hcd *xhci,
345 		unsigned int slot_id,
346 		unsigned int ep_index)
347 {
348 	unsigned int stream_id;
349 	struct xhci_virt_ep *ep;
350 
351 	ep = &xhci->devs[slot_id]->eps[ep_index];
352 
353 	/* A ring has pending URBs if its TD list is not empty */
354 	if (!(ep->ep_state & EP_HAS_STREAMS)) {
355 		if (!(list_empty(&ep->ring->td_list)))
356 			ring_ep_doorbell(xhci, slot_id, ep_index, 0);
357 		return;
358 	}
359 
360 	for (stream_id = 1; stream_id < ep->stream_info->num_streams;
361 			stream_id++) {
362 		struct xhci_stream_info *stream_info = ep->stream_info;
363 		if (!list_empty(&stream_info->stream_rings[stream_id]->td_list))
364 			ring_ep_doorbell(xhci, slot_id, ep_index, stream_id);
365 	}
366 }
367 
368 /*
369  * Find the segment that trb is in.  Start searching in start_seg.
370  * If we must move past a segment that has a link TRB with a toggle cycle state
371  * bit set, then we will toggle the value pointed at by cycle_state.
372  */
373 static struct xhci_segment *find_trb_seg(
374 		struct xhci_segment *start_seg,
375 		union xhci_trb	*trb, int *cycle_state)
376 {
377 	struct xhci_segment *cur_seg = start_seg;
378 	struct xhci_generic_trb *generic_trb;
379 
380 	while (cur_seg->trbs > trb ||
381 			&cur_seg->trbs[TRBS_PER_SEGMENT - 1] < trb) {
382 		generic_trb = &cur_seg->trbs[TRBS_PER_SEGMENT - 1].generic;
383 		if ((generic_trb->field[3] & TRB_TYPE_BITMASK) ==
384 				TRB_TYPE(TRB_LINK) &&
385 				(generic_trb->field[3] & LINK_TOGGLE))
386 			*cycle_state = ~(*cycle_state) & 0x1;
387 		cur_seg = cur_seg->next;
388 		if (cur_seg == start_seg)
389 			/* Looped over the entire list.  Oops! */
390 			return NULL;
391 	}
392 	return cur_seg;
393 }
394 
395 
396 static struct xhci_ring *xhci_triad_to_transfer_ring(struct xhci_hcd *xhci,
397 		unsigned int slot_id, unsigned int ep_index,
398 		unsigned int stream_id)
399 {
400 	struct xhci_virt_ep *ep;
401 
402 	ep = &xhci->devs[slot_id]->eps[ep_index];
403 	/* Common case: no streams */
404 	if (!(ep->ep_state & EP_HAS_STREAMS))
405 		return ep->ring;
406 
407 	if (stream_id == 0) {
408 		xhci_warn(xhci,
409 				"WARN: Slot ID %u, ep index %u has streams, "
410 				"but URB has no stream ID.\n",
411 				slot_id, ep_index);
412 		return NULL;
413 	}
414 
415 	if (stream_id < ep->stream_info->num_streams)
416 		return ep->stream_info->stream_rings[stream_id];
417 
418 	xhci_warn(xhci,
419 			"WARN: Slot ID %u, ep index %u has "
420 			"stream IDs 1 to %u allocated, "
421 			"but stream ID %u is requested.\n",
422 			slot_id, ep_index,
423 			ep->stream_info->num_streams - 1,
424 			stream_id);
425 	return NULL;
426 }
427 
428 /* Get the right ring for the given URB.
429  * If the endpoint supports streams, boundary check the URB's stream ID.
430  * If the endpoint doesn't support streams, return the singular endpoint ring.
431  */
432 static struct xhci_ring *xhci_urb_to_transfer_ring(struct xhci_hcd *xhci,
433 		struct urb *urb)
434 {
435 	return xhci_triad_to_transfer_ring(xhci, urb->dev->slot_id,
436 		xhci_get_endpoint_index(&urb->ep->desc), urb->stream_id);
437 }
438 
439 /*
440  * Move the xHC's endpoint ring dequeue pointer past cur_td.
441  * Record the new state of the xHC's endpoint ring dequeue segment,
442  * dequeue pointer, and new consumer cycle state in state.
443  * Update our internal representation of the ring's dequeue pointer.
444  *
445  * We do this in three jumps:
446  *  - First we update our new ring state to be the same as when the xHC stopped.
447  *  - Then we traverse the ring to find the segment that contains
448  *    the last TRB in the TD.  We toggle the xHC's new cycle state when we pass
449  *    any link TRBs with the toggle cycle bit set.
450  *  - Finally we move the dequeue state one TRB further, toggling the cycle bit
451  *    if we've moved it past a link TRB with the toggle cycle bit set.
452  */
453 void xhci_find_new_dequeue_state(struct xhci_hcd *xhci,
454 		unsigned int slot_id, unsigned int ep_index,
455 		unsigned int stream_id, struct xhci_td *cur_td,
456 		struct xhci_dequeue_state *state)
457 {
458 	struct xhci_virt_device *dev = xhci->devs[slot_id];
459 	struct xhci_ring *ep_ring;
460 	struct xhci_generic_trb *trb;
461 	struct xhci_ep_ctx *ep_ctx;
462 	dma_addr_t addr;
463 
464 	ep_ring = xhci_triad_to_transfer_ring(xhci, slot_id,
465 			ep_index, stream_id);
466 	if (!ep_ring) {
467 		xhci_warn(xhci, "WARN can't find new dequeue state "
468 				"for invalid stream ID %u.\n",
469 				stream_id);
470 		return;
471 	}
472 	state->new_cycle_state = 0;
473 	xhci_dbg(xhci, "Finding segment containing stopped TRB.\n");
474 	state->new_deq_seg = find_trb_seg(cur_td->start_seg,
475 			dev->eps[ep_index].stopped_trb,
476 			&state->new_cycle_state);
477 	if (!state->new_deq_seg)
478 		BUG();
479 	/* Dig out the cycle state saved by the xHC during the stop ep cmd */
480 	xhci_dbg(xhci, "Finding endpoint context\n");
481 	ep_ctx = xhci_get_ep_ctx(xhci, dev->out_ctx, ep_index);
482 	state->new_cycle_state = 0x1 & ep_ctx->deq;
483 
484 	state->new_deq_ptr = cur_td->last_trb;
485 	xhci_dbg(xhci, "Finding segment containing last TRB in TD.\n");
486 	state->new_deq_seg = find_trb_seg(state->new_deq_seg,
487 			state->new_deq_ptr,
488 			&state->new_cycle_state);
489 	if (!state->new_deq_seg)
490 		BUG();
491 
492 	trb = &state->new_deq_ptr->generic;
493 	if ((trb->field[3] & TRB_TYPE_BITMASK) == TRB_TYPE(TRB_LINK) &&
494 				(trb->field[3] & LINK_TOGGLE))
495 		state->new_cycle_state = ~(state->new_cycle_state) & 0x1;
496 	next_trb(xhci, ep_ring, &state->new_deq_seg, &state->new_deq_ptr);
497 
498 	/* Don't update the ring cycle state for the producer (us). */
499 	xhci_dbg(xhci, "New dequeue segment = %p (virtual)\n",
500 			state->new_deq_seg);
501 	addr = xhci_trb_virt_to_dma(state->new_deq_seg, state->new_deq_ptr);
502 	xhci_dbg(xhci, "New dequeue pointer = 0x%llx (DMA)\n",
503 			(unsigned long long) addr);
504 	xhci_dbg(xhci, "Setting dequeue pointer in internal ring state.\n");
505 	ep_ring->dequeue = state->new_deq_ptr;
506 	ep_ring->deq_seg = state->new_deq_seg;
507 }
508 
509 static void td_to_noop(struct xhci_hcd *xhci, struct xhci_ring *ep_ring,
510 		struct xhci_td *cur_td)
511 {
512 	struct xhci_segment *cur_seg;
513 	union xhci_trb *cur_trb;
514 
515 	for (cur_seg = cur_td->start_seg, cur_trb = cur_td->first_trb;
516 			true;
517 			next_trb(xhci, ep_ring, &cur_seg, &cur_trb)) {
518 		if ((cur_trb->generic.field[3] & TRB_TYPE_BITMASK) ==
519 				TRB_TYPE(TRB_LINK)) {
520 			/* Unchain any chained Link TRBs, but
521 			 * leave the pointers intact.
522 			 */
523 			cur_trb->generic.field[3] &= ~TRB_CHAIN;
524 			xhci_dbg(xhci, "Cancel (unchain) link TRB\n");
525 			xhci_dbg(xhci, "Address = %p (0x%llx dma); "
526 					"in seg %p (0x%llx dma)\n",
527 					cur_trb,
528 					(unsigned long long)xhci_trb_virt_to_dma(cur_seg, cur_trb),
529 					cur_seg,
530 					(unsigned long long)cur_seg->dma);
531 		} else {
532 			cur_trb->generic.field[0] = 0;
533 			cur_trb->generic.field[1] = 0;
534 			cur_trb->generic.field[2] = 0;
535 			/* Preserve only the cycle bit of this TRB */
536 			cur_trb->generic.field[3] &= TRB_CYCLE;
537 			cur_trb->generic.field[3] |= TRB_TYPE(TRB_TR_NOOP);
538 			xhci_dbg(xhci, "Cancel TRB %p (0x%llx dma) "
539 					"in seg %p (0x%llx dma)\n",
540 					cur_trb,
541 					(unsigned long long)xhci_trb_virt_to_dma(cur_seg, cur_trb),
542 					cur_seg,
543 					(unsigned long long)cur_seg->dma);
544 		}
545 		if (cur_trb == cur_td->last_trb)
546 			break;
547 	}
548 }
549 
550 static int queue_set_tr_deq(struct xhci_hcd *xhci, int slot_id,
551 		unsigned int ep_index, unsigned int stream_id,
552 		struct xhci_segment *deq_seg,
553 		union xhci_trb *deq_ptr, u32 cycle_state);
554 
555 void xhci_queue_new_dequeue_state(struct xhci_hcd *xhci,
556 		unsigned int slot_id, unsigned int ep_index,
557 		unsigned int stream_id,
558 		struct xhci_dequeue_state *deq_state)
559 {
560 	struct xhci_virt_ep *ep = &xhci->devs[slot_id]->eps[ep_index];
561 
562 	xhci_dbg(xhci, "Set TR Deq Ptr cmd, new deq seg = %p (0x%llx dma), "
563 			"new deq ptr = %p (0x%llx dma), new cycle = %u\n",
564 			deq_state->new_deq_seg,
565 			(unsigned long long)deq_state->new_deq_seg->dma,
566 			deq_state->new_deq_ptr,
567 			(unsigned long long)xhci_trb_virt_to_dma(deq_state->new_deq_seg, deq_state->new_deq_ptr),
568 			deq_state->new_cycle_state);
569 	queue_set_tr_deq(xhci, slot_id, ep_index, stream_id,
570 			deq_state->new_deq_seg,
571 			deq_state->new_deq_ptr,
572 			(u32) deq_state->new_cycle_state);
573 	/* Stop the TD queueing code from ringing the doorbell until
574 	 * this command completes.  The HC won't set the dequeue pointer
575 	 * if the ring is running, and ringing the doorbell starts the
576 	 * ring running.
577 	 */
578 	ep->ep_state |= SET_DEQ_PENDING;
579 }
580 
581 static inline void xhci_stop_watchdog_timer_in_irq(struct xhci_hcd *xhci,
582 		struct xhci_virt_ep *ep)
583 {
584 	ep->ep_state &= ~EP_HALT_PENDING;
585 	/* Can't del_timer_sync in interrupt, so we attempt to cancel.  If the
586 	 * timer is running on another CPU, we don't decrement stop_cmds_pending
587 	 * (since we didn't successfully stop the watchdog timer).
588 	 */
589 	if (del_timer(&ep->stop_cmd_timer))
590 		ep->stop_cmds_pending--;
591 }
592 
593 /* Must be called with xhci->lock held in interrupt context */
594 static void xhci_giveback_urb_in_irq(struct xhci_hcd *xhci,
595 		struct xhci_td *cur_td, int status, char *adjective)
596 {
597 	struct usb_hcd *hcd = xhci_to_hcd(xhci);
598 	struct urb	*urb;
599 	struct urb_priv	*urb_priv;
600 
601 	urb = cur_td->urb;
602 	urb_priv = urb->hcpriv;
603 	urb_priv->td_cnt++;
604 
605 	/* Only giveback urb when this is the last td in urb */
606 	if (urb_priv->td_cnt == urb_priv->length) {
607 		usb_hcd_unlink_urb_from_ep(hcd, urb);
608 		xhci_dbg(xhci, "Giveback %s URB %p\n", adjective, urb);
609 
610 		spin_unlock(&xhci->lock);
611 		usb_hcd_giveback_urb(hcd, urb, status);
612 		xhci_urb_free_priv(xhci, urb_priv);
613 		spin_lock(&xhci->lock);
614 		xhci_dbg(xhci, "%s URB given back\n", adjective);
615 	}
616 }
617 
618 /*
619  * When we get a command completion for a Stop Endpoint Command, we need to
620  * unlink any cancelled TDs from the ring.  There are two ways to do that:
621  *
622  *  1. If the HW was in the middle of processing the TD that needs to be
623  *     cancelled, then we must move the ring's dequeue pointer past the last TRB
624  *     in the TD with a Set Dequeue Pointer Command.
625  *  2. Otherwise, we turn all the TRBs in the TD into No-op TRBs (with the chain
626  *     bit cleared) so that the HW will skip over them.
627  */
628 static void handle_stopped_endpoint(struct xhci_hcd *xhci,
629 		union xhci_trb *trb)
630 {
631 	unsigned int slot_id;
632 	unsigned int ep_index;
633 	struct xhci_ring *ep_ring;
634 	struct xhci_virt_ep *ep;
635 	struct list_head *entry;
636 	struct xhci_td *cur_td = NULL;
637 	struct xhci_td *last_unlinked_td;
638 
639 	struct xhci_dequeue_state deq_state;
640 
641 	memset(&deq_state, 0, sizeof(deq_state));
642 	slot_id = TRB_TO_SLOT_ID(trb->generic.field[3]);
643 	ep_index = TRB_TO_EP_INDEX(trb->generic.field[3]);
644 	ep = &xhci->devs[slot_id]->eps[ep_index];
645 
646 	if (list_empty(&ep->cancelled_td_list)) {
647 		xhci_stop_watchdog_timer_in_irq(xhci, ep);
648 		ring_doorbell_for_active_rings(xhci, slot_id, ep_index);
649 		return;
650 	}
651 
652 	/* Fix up the ep ring first, so HW stops executing cancelled TDs.
653 	 * We have the xHCI lock, so nothing can modify this list until we drop
654 	 * it.  We're also in the event handler, so we can't get re-interrupted
655 	 * if another Stop Endpoint command completes
656 	 */
657 	list_for_each(entry, &ep->cancelled_td_list) {
658 		cur_td = list_entry(entry, struct xhci_td, cancelled_td_list);
659 		xhci_dbg(xhci, "Cancelling TD starting at %p, 0x%llx (dma).\n",
660 				cur_td->first_trb,
661 				(unsigned long long)xhci_trb_virt_to_dma(cur_td->start_seg, cur_td->first_trb));
662 		ep_ring = xhci_urb_to_transfer_ring(xhci, cur_td->urb);
663 		if (!ep_ring) {
664 			/* This shouldn't happen unless a driver is mucking
665 			 * with the stream ID after submission.  This will
666 			 * leave the TD on the hardware ring, and the hardware
667 			 * will try to execute it, and may access a buffer
668 			 * that has already been freed.  In the best case, the
669 			 * hardware will execute it, and the event handler will
670 			 * ignore the completion event for that TD, since it was
671 			 * removed from the td_list for that endpoint.  In
672 			 * short, don't muck with the stream ID after
673 			 * submission.
674 			 */
675 			xhci_warn(xhci, "WARN Cancelled URB %p "
676 					"has invalid stream ID %u.\n",
677 					cur_td->urb,
678 					cur_td->urb->stream_id);
679 			goto remove_finished_td;
680 		}
681 		/*
682 		 * If we stopped on the TD we need to cancel, then we have to
683 		 * move the xHC endpoint ring dequeue pointer past this TD.
684 		 */
685 		if (cur_td == ep->stopped_td)
686 			xhci_find_new_dequeue_state(xhci, slot_id, ep_index,
687 					cur_td->urb->stream_id,
688 					cur_td, &deq_state);
689 		else
690 			td_to_noop(xhci, ep_ring, cur_td);
691 remove_finished_td:
692 		/*
693 		 * The event handler won't see a completion for this TD anymore,
694 		 * so remove it from the endpoint ring's TD list.  Keep it in
695 		 * the cancelled TD list for URB completion later.
696 		 */
697 		list_del(&cur_td->td_list);
698 	}
699 	last_unlinked_td = cur_td;
700 	xhci_stop_watchdog_timer_in_irq(xhci, ep);
701 
702 	/* If necessary, queue a Set Transfer Ring Dequeue Pointer command */
703 	if (deq_state.new_deq_ptr && deq_state.new_deq_seg) {
704 		xhci_queue_new_dequeue_state(xhci,
705 				slot_id, ep_index,
706 				ep->stopped_td->urb->stream_id,
707 				&deq_state);
708 		xhci_ring_cmd_db(xhci);
709 	} else {
710 		/* Otherwise ring the doorbell(s) to restart queued transfers */
711 		ring_doorbell_for_active_rings(xhci, slot_id, ep_index);
712 	}
713 	ep->stopped_td = NULL;
714 	ep->stopped_trb = NULL;
715 
716 	/*
717 	 * Drop the lock and complete the URBs in the cancelled TD list.
718 	 * New TDs to be cancelled might be added to the end of the list before
719 	 * we can complete all the URBs for the TDs we already unlinked.
720 	 * So stop when we've completed the URB for the last TD we unlinked.
721 	 */
722 	do {
723 		cur_td = list_entry(ep->cancelled_td_list.next,
724 				struct xhci_td, cancelled_td_list);
725 		list_del(&cur_td->cancelled_td_list);
726 
727 		/* Clean up the cancelled URB */
728 		/* Doesn't matter what we pass for status, since the core will
729 		 * just overwrite it (because the URB has been unlinked).
730 		 */
731 		xhci_giveback_urb_in_irq(xhci, cur_td, 0, "cancelled");
732 
733 		/* Stop processing the cancelled list if the watchdog timer is
734 		 * running.
735 		 */
736 		if (xhci->xhc_state & XHCI_STATE_DYING)
737 			return;
738 	} while (cur_td != last_unlinked_td);
739 
740 	/* Return to the event handler with xhci->lock re-acquired */
741 }
742 
743 /* Watchdog timer function for when a stop endpoint command fails to complete.
744  * In this case, we assume the host controller is broken or dying or dead.  The
745  * host may still be completing some other events, so we have to be careful to
746  * let the event ring handler and the URB dequeueing/enqueueing functions know
747  * through xhci->state.
748  *
749  * The timer may also fire if the host takes a very long time to respond to the
750  * command, and the stop endpoint command completion handler cannot delete the
751  * timer before the timer function is called.  Another endpoint cancellation may
752  * sneak in before the timer function can grab the lock, and that may queue
753  * another stop endpoint command and add the timer back.  So we cannot use a
754  * simple flag to say whether there is a pending stop endpoint command for a
755  * particular endpoint.
756  *
757  * Instead we use a combination of that flag and a counter for the number of
758  * pending stop endpoint commands.  If the timer is the tail end of the last
759  * stop endpoint command, and the endpoint's command is still pending, we assume
760  * the host is dying.
761  */
762 void xhci_stop_endpoint_command_watchdog(unsigned long arg)
763 {
764 	struct xhci_hcd *xhci;
765 	struct xhci_virt_ep *ep;
766 	struct xhci_virt_ep *temp_ep;
767 	struct xhci_ring *ring;
768 	struct xhci_td *cur_td;
769 	int ret, i, j;
770 
771 	ep = (struct xhci_virt_ep *) arg;
772 	xhci = ep->xhci;
773 
774 	spin_lock(&xhci->lock);
775 
776 	ep->stop_cmds_pending--;
777 	if (xhci->xhc_state & XHCI_STATE_DYING) {
778 		xhci_dbg(xhci, "Stop EP timer ran, but another timer marked "
779 				"xHCI as DYING, exiting.\n");
780 		spin_unlock(&xhci->lock);
781 		return;
782 	}
783 	if (!(ep->stop_cmds_pending == 0 && (ep->ep_state & EP_HALT_PENDING))) {
784 		xhci_dbg(xhci, "Stop EP timer ran, but no command pending, "
785 				"exiting.\n");
786 		spin_unlock(&xhci->lock);
787 		return;
788 	}
789 
790 	xhci_warn(xhci, "xHCI host not responding to stop endpoint command.\n");
791 	xhci_warn(xhci, "Assuming host is dying, halting host.\n");
792 	/* Oops, HC is dead or dying or at least not responding to the stop
793 	 * endpoint command.
794 	 */
795 	xhci->xhc_state |= XHCI_STATE_DYING;
796 	/* Disable interrupts from the host controller and start halting it */
797 	xhci_quiesce(xhci);
798 	spin_unlock(&xhci->lock);
799 
800 	ret = xhci_halt(xhci);
801 
802 	spin_lock(&xhci->lock);
803 	if (ret < 0) {
804 		/* This is bad; the host is not responding to commands and it's
805 		 * not allowing itself to be halted.  At least interrupts are
806 		 * disabled, so we can set HC_STATE_HALT and notify the
807 		 * USB core.  But if we call usb_hc_died(), it will attempt to
808 		 * disconnect all device drivers under this host.  Those
809 		 * disconnect() methods will wait for all URBs to be unlinked,
810 		 * so we must complete them.
811 		 */
812 		xhci_warn(xhci, "Non-responsive xHCI host is not halting.\n");
813 		xhci_warn(xhci, "Completing active URBs anyway.\n");
814 		/* We could turn all TDs on the rings to no-ops.  This won't
815 		 * help if the host has cached part of the ring, and is slow if
816 		 * we want to preserve the cycle bit.  Skip it and hope the host
817 		 * doesn't touch the memory.
818 		 */
819 	}
820 	for (i = 0; i < MAX_HC_SLOTS; i++) {
821 		if (!xhci->devs[i])
822 			continue;
823 		for (j = 0; j < 31; j++) {
824 			temp_ep = &xhci->devs[i]->eps[j];
825 			ring = temp_ep->ring;
826 			if (!ring)
827 				continue;
828 			xhci_dbg(xhci, "Killing URBs for slot ID %u, "
829 					"ep index %u\n", i, j);
830 			while (!list_empty(&ring->td_list)) {
831 				cur_td = list_first_entry(&ring->td_list,
832 						struct xhci_td,
833 						td_list);
834 				list_del(&cur_td->td_list);
835 				if (!list_empty(&cur_td->cancelled_td_list))
836 					list_del(&cur_td->cancelled_td_list);
837 				xhci_giveback_urb_in_irq(xhci, cur_td,
838 						-ESHUTDOWN, "killed");
839 			}
840 			while (!list_empty(&temp_ep->cancelled_td_list)) {
841 				cur_td = list_first_entry(
842 						&temp_ep->cancelled_td_list,
843 						struct xhci_td,
844 						cancelled_td_list);
845 				list_del(&cur_td->cancelled_td_list);
846 				xhci_giveback_urb_in_irq(xhci, cur_td,
847 						-ESHUTDOWN, "killed");
848 			}
849 		}
850 	}
851 	spin_unlock(&xhci->lock);
852 	xhci_to_hcd(xhci)->state = HC_STATE_HALT;
853 	xhci_dbg(xhci, "Calling usb_hc_died()\n");
854 	usb_hc_died(xhci_to_hcd(xhci));
855 	xhci_dbg(xhci, "xHCI host controller is dead.\n");
856 }
857 
858 /*
859  * When we get a completion for a Set Transfer Ring Dequeue Pointer command,
860  * we need to clear the set deq pending flag in the endpoint ring state, so that
861  * the TD queueing code can ring the doorbell again.  We also need to ring the
862  * endpoint doorbell to restart the ring, but only if there aren't more
863  * cancellations pending.
864  */
865 static void handle_set_deq_completion(struct xhci_hcd *xhci,
866 		struct xhci_event_cmd *event,
867 		union xhci_trb *trb)
868 {
869 	unsigned int slot_id;
870 	unsigned int ep_index;
871 	unsigned int stream_id;
872 	struct xhci_ring *ep_ring;
873 	struct xhci_virt_device *dev;
874 	struct xhci_ep_ctx *ep_ctx;
875 	struct xhci_slot_ctx *slot_ctx;
876 
877 	slot_id = TRB_TO_SLOT_ID(trb->generic.field[3]);
878 	ep_index = TRB_TO_EP_INDEX(trb->generic.field[3]);
879 	stream_id = TRB_TO_STREAM_ID(trb->generic.field[2]);
880 	dev = xhci->devs[slot_id];
881 
882 	ep_ring = xhci_stream_id_to_ring(dev, ep_index, stream_id);
883 	if (!ep_ring) {
884 		xhci_warn(xhci, "WARN Set TR deq ptr command for "
885 				"freed stream ID %u\n",
886 				stream_id);
887 		/* XXX: Harmless??? */
888 		dev->eps[ep_index].ep_state &= ~SET_DEQ_PENDING;
889 		return;
890 	}
891 
892 	ep_ctx = xhci_get_ep_ctx(xhci, dev->out_ctx, ep_index);
893 	slot_ctx = xhci_get_slot_ctx(xhci, dev->out_ctx);
894 
895 	if (GET_COMP_CODE(event->status) != COMP_SUCCESS) {
896 		unsigned int ep_state;
897 		unsigned int slot_state;
898 
899 		switch (GET_COMP_CODE(event->status)) {
900 		case COMP_TRB_ERR:
901 			xhci_warn(xhci, "WARN Set TR Deq Ptr cmd invalid because "
902 					"of stream ID configuration\n");
903 			break;
904 		case COMP_CTX_STATE:
905 			xhci_warn(xhci, "WARN Set TR Deq Ptr cmd failed due "
906 					"to incorrect slot or ep state.\n");
907 			ep_state = ep_ctx->ep_info;
908 			ep_state &= EP_STATE_MASK;
909 			slot_state = slot_ctx->dev_state;
910 			slot_state = GET_SLOT_STATE(slot_state);
911 			xhci_dbg(xhci, "Slot state = %u, EP state = %u\n",
912 					slot_state, ep_state);
913 			break;
914 		case COMP_EBADSLT:
915 			xhci_warn(xhci, "WARN Set TR Deq Ptr cmd failed because "
916 					"slot %u was not enabled.\n", slot_id);
917 			break;
918 		default:
919 			xhci_warn(xhci, "WARN Set TR Deq Ptr cmd with unknown "
920 					"completion code of %u.\n",
921 					GET_COMP_CODE(event->status));
922 			break;
923 		}
924 		/* OK what do we do now?  The endpoint state is hosed, and we
925 		 * should never get to this point if the synchronization between
926 		 * queueing, and endpoint state are correct.  This might happen
927 		 * if the device gets disconnected after we've finished
928 		 * cancelling URBs, which might not be an error...
929 		 */
930 	} else {
931 		xhci_dbg(xhci, "Successful Set TR Deq Ptr cmd, deq = @%08llx\n",
932 				ep_ctx->deq);
933 	}
934 
935 	dev->eps[ep_index].ep_state &= ~SET_DEQ_PENDING;
936 	/* Restart any rings with pending URBs */
937 	ring_doorbell_for_active_rings(xhci, slot_id, ep_index);
938 }
939 
940 static void handle_reset_ep_completion(struct xhci_hcd *xhci,
941 		struct xhci_event_cmd *event,
942 		union xhci_trb *trb)
943 {
944 	int slot_id;
945 	unsigned int ep_index;
946 
947 	slot_id = TRB_TO_SLOT_ID(trb->generic.field[3]);
948 	ep_index = TRB_TO_EP_INDEX(trb->generic.field[3]);
949 	/* This command will only fail if the endpoint wasn't halted,
950 	 * but we don't care.
951 	 */
952 	xhci_dbg(xhci, "Ignoring reset ep completion code of %u\n",
953 			(unsigned int) GET_COMP_CODE(event->status));
954 
955 	/* HW with the reset endpoint quirk needs to have a configure endpoint
956 	 * command complete before the endpoint can be used.  Queue that here
957 	 * because the HW can't handle two commands being queued in a row.
958 	 */
959 	if (xhci->quirks & XHCI_RESET_EP_QUIRK) {
960 		xhci_dbg(xhci, "Queueing configure endpoint command\n");
961 		xhci_queue_configure_endpoint(xhci,
962 				xhci->devs[slot_id]->in_ctx->dma, slot_id,
963 				false);
964 		xhci_ring_cmd_db(xhci);
965 	} else {
966 		/* Clear our internal halted state and restart the ring(s) */
967 		xhci->devs[slot_id]->eps[ep_index].ep_state &= ~EP_HALTED;
968 		ring_doorbell_for_active_rings(xhci, slot_id, ep_index);
969 	}
970 }
971 
972 /* Check to see if a command in the device's command queue matches this one.
973  * Signal the completion or free the command, and return 1.  Return 0 if the
974  * completed command isn't at the head of the command list.
975  */
976 static int handle_cmd_in_cmd_wait_list(struct xhci_hcd *xhci,
977 		struct xhci_virt_device *virt_dev,
978 		struct xhci_event_cmd *event)
979 {
980 	struct xhci_command *command;
981 
982 	if (list_empty(&virt_dev->cmd_list))
983 		return 0;
984 
985 	command = list_entry(virt_dev->cmd_list.next,
986 			struct xhci_command, cmd_list);
987 	if (xhci->cmd_ring->dequeue != command->command_trb)
988 		return 0;
989 
990 	command->status =
991 		GET_COMP_CODE(event->status);
992 	list_del(&command->cmd_list);
993 	if (command->completion)
994 		complete(command->completion);
995 	else
996 		xhci_free_command(xhci, command);
997 	return 1;
998 }
999 
1000 static void handle_cmd_completion(struct xhci_hcd *xhci,
1001 		struct xhci_event_cmd *event)
1002 {
1003 	int slot_id = TRB_TO_SLOT_ID(event->flags);
1004 	u64 cmd_dma;
1005 	dma_addr_t cmd_dequeue_dma;
1006 	struct xhci_input_control_ctx *ctrl_ctx;
1007 	struct xhci_virt_device *virt_dev;
1008 	unsigned int ep_index;
1009 	struct xhci_ring *ep_ring;
1010 	unsigned int ep_state;
1011 
1012 	cmd_dma = event->cmd_trb;
1013 	cmd_dequeue_dma = xhci_trb_virt_to_dma(xhci->cmd_ring->deq_seg,
1014 			xhci->cmd_ring->dequeue);
1015 	/* Is the command ring deq ptr out of sync with the deq seg ptr? */
1016 	if (cmd_dequeue_dma == 0) {
1017 		xhci->error_bitmask |= 1 << 4;
1018 		return;
1019 	}
1020 	/* Does the DMA address match our internal dequeue pointer address? */
1021 	if (cmd_dma != (u64) cmd_dequeue_dma) {
1022 		xhci->error_bitmask |= 1 << 5;
1023 		return;
1024 	}
1025 	switch (xhci->cmd_ring->dequeue->generic.field[3] & TRB_TYPE_BITMASK) {
1026 	case TRB_TYPE(TRB_ENABLE_SLOT):
1027 		if (GET_COMP_CODE(event->status) == COMP_SUCCESS)
1028 			xhci->slot_id = slot_id;
1029 		else
1030 			xhci->slot_id = 0;
1031 		complete(&xhci->addr_dev);
1032 		break;
1033 	case TRB_TYPE(TRB_DISABLE_SLOT):
1034 		if (xhci->devs[slot_id])
1035 			xhci_free_virt_device(xhci, slot_id);
1036 		break;
1037 	case TRB_TYPE(TRB_CONFIG_EP):
1038 		virt_dev = xhci->devs[slot_id];
1039 		if (handle_cmd_in_cmd_wait_list(xhci, virt_dev, event))
1040 			break;
1041 		/*
1042 		 * Configure endpoint commands can come from the USB core
1043 		 * configuration or alt setting changes, or because the HW
1044 		 * needed an extra configure endpoint command after a reset
1045 		 * endpoint command or streams were being configured.
1046 		 * If the command was for a halted endpoint, the xHCI driver
1047 		 * is not waiting on the configure endpoint command.
1048 		 */
1049 		ctrl_ctx = xhci_get_input_control_ctx(xhci,
1050 				virt_dev->in_ctx);
1051 		/* Input ctx add_flags are the endpoint index plus one */
1052 		ep_index = xhci_last_valid_endpoint(ctrl_ctx->add_flags) - 1;
1053 		/* A usb_set_interface() call directly after clearing a halted
1054 		 * condition may race on this quirky hardware.  Not worth
1055 		 * worrying about, since this is prototype hardware.  Not sure
1056 		 * if this will work for streams, but streams support was
1057 		 * untested on this prototype.
1058 		 */
1059 		if (xhci->quirks & XHCI_RESET_EP_QUIRK &&
1060 				ep_index != (unsigned int) -1 &&
1061 				ctrl_ctx->add_flags - SLOT_FLAG ==
1062 					ctrl_ctx->drop_flags) {
1063 			ep_ring = xhci->devs[slot_id]->eps[ep_index].ring;
1064 			ep_state = xhci->devs[slot_id]->eps[ep_index].ep_state;
1065 			if (!(ep_state & EP_HALTED))
1066 				goto bandwidth_change;
1067 			xhci_dbg(xhci, "Completed config ep cmd - "
1068 					"last ep index = %d, state = %d\n",
1069 					ep_index, ep_state);
1070 			/* Clear internal halted state and restart ring(s) */
1071 			xhci->devs[slot_id]->eps[ep_index].ep_state &=
1072 				~EP_HALTED;
1073 			ring_doorbell_for_active_rings(xhci, slot_id, ep_index);
1074 			break;
1075 		}
1076 bandwidth_change:
1077 		xhci_dbg(xhci, "Completed config ep cmd\n");
1078 		xhci->devs[slot_id]->cmd_status =
1079 			GET_COMP_CODE(event->status);
1080 		complete(&xhci->devs[slot_id]->cmd_completion);
1081 		break;
1082 	case TRB_TYPE(TRB_EVAL_CONTEXT):
1083 		virt_dev = xhci->devs[slot_id];
1084 		if (handle_cmd_in_cmd_wait_list(xhci, virt_dev, event))
1085 			break;
1086 		xhci->devs[slot_id]->cmd_status = GET_COMP_CODE(event->status);
1087 		complete(&xhci->devs[slot_id]->cmd_completion);
1088 		break;
1089 	case TRB_TYPE(TRB_ADDR_DEV):
1090 		xhci->devs[slot_id]->cmd_status = GET_COMP_CODE(event->status);
1091 		complete(&xhci->addr_dev);
1092 		break;
1093 	case TRB_TYPE(TRB_STOP_RING):
1094 		handle_stopped_endpoint(xhci, xhci->cmd_ring->dequeue);
1095 		break;
1096 	case TRB_TYPE(TRB_SET_DEQ):
1097 		handle_set_deq_completion(xhci, event, xhci->cmd_ring->dequeue);
1098 		break;
1099 	case TRB_TYPE(TRB_CMD_NOOP):
1100 		++xhci->noops_handled;
1101 		break;
1102 	case TRB_TYPE(TRB_RESET_EP):
1103 		handle_reset_ep_completion(xhci, event, xhci->cmd_ring->dequeue);
1104 		break;
1105 	case TRB_TYPE(TRB_RESET_DEV):
1106 		xhci_dbg(xhci, "Completed reset device command.\n");
1107 		slot_id = TRB_TO_SLOT_ID(
1108 				xhci->cmd_ring->dequeue->generic.field[3]);
1109 		virt_dev = xhci->devs[slot_id];
1110 		if (virt_dev)
1111 			handle_cmd_in_cmd_wait_list(xhci, virt_dev, event);
1112 		else
1113 			xhci_warn(xhci, "Reset device command completion "
1114 					"for disabled slot %u\n", slot_id);
1115 		break;
1116 	case TRB_TYPE(TRB_NEC_GET_FW):
1117 		if (!(xhci->quirks & XHCI_NEC_HOST)) {
1118 			xhci->error_bitmask |= 1 << 6;
1119 			break;
1120 		}
1121 		xhci_dbg(xhci, "NEC firmware version %2x.%02x\n",
1122 				NEC_FW_MAJOR(event->status),
1123 				NEC_FW_MINOR(event->status));
1124 		break;
1125 	default:
1126 		/* Skip over unknown commands on the event ring */
1127 		xhci->error_bitmask |= 1 << 6;
1128 		break;
1129 	}
1130 	inc_deq(xhci, xhci->cmd_ring, false);
1131 }
1132 
1133 static void handle_vendor_event(struct xhci_hcd *xhci,
1134 		union xhci_trb *event)
1135 {
1136 	u32 trb_type;
1137 
1138 	trb_type = TRB_FIELD_TO_TYPE(event->generic.field[3]);
1139 	xhci_dbg(xhci, "Vendor specific event TRB type = %u\n", trb_type);
1140 	if (trb_type == TRB_NEC_CMD_COMP && (xhci->quirks & XHCI_NEC_HOST))
1141 		handle_cmd_completion(xhci, &event->event_cmd);
1142 }
1143 
1144 static void handle_port_status(struct xhci_hcd *xhci,
1145 		union xhci_trb *event)
1146 {
1147 	u32 port_id;
1148 
1149 	/* Port status change events always have a successful completion code */
1150 	if (GET_COMP_CODE(event->generic.field[2]) != COMP_SUCCESS) {
1151 		xhci_warn(xhci, "WARN: xHC returned failed port status event\n");
1152 		xhci->error_bitmask |= 1 << 8;
1153 	}
1154 	/* FIXME: core doesn't care about all port link state changes yet */
1155 	port_id = GET_PORT_ID(event->generic.field[0]);
1156 	xhci_dbg(xhci, "Port Status Change Event for port %d\n", port_id);
1157 
1158 	/* Update event ring dequeue pointer before dropping the lock */
1159 	inc_deq(xhci, xhci->event_ring, true);
1160 
1161 	spin_unlock(&xhci->lock);
1162 	/* Pass this up to the core */
1163 	usb_hcd_poll_rh_status(xhci_to_hcd(xhci));
1164 	spin_lock(&xhci->lock);
1165 }
1166 
1167 /*
1168  * This TD is defined by the TRBs starting at start_trb in start_seg and ending
1169  * at end_trb, which may be in another segment.  If the suspect DMA address is a
1170  * TRB in this TD, this function returns that TRB's segment.  Otherwise it
1171  * returns 0.
1172  */
1173 struct xhci_segment *trb_in_td(struct xhci_segment *start_seg,
1174 		union xhci_trb	*start_trb,
1175 		union xhci_trb	*end_trb,
1176 		dma_addr_t	suspect_dma)
1177 {
1178 	dma_addr_t start_dma;
1179 	dma_addr_t end_seg_dma;
1180 	dma_addr_t end_trb_dma;
1181 	struct xhci_segment *cur_seg;
1182 
1183 	start_dma = xhci_trb_virt_to_dma(start_seg, start_trb);
1184 	cur_seg = start_seg;
1185 
1186 	do {
1187 		if (start_dma == 0)
1188 			return NULL;
1189 		/* We may get an event for a Link TRB in the middle of a TD */
1190 		end_seg_dma = xhci_trb_virt_to_dma(cur_seg,
1191 				&cur_seg->trbs[TRBS_PER_SEGMENT - 1]);
1192 		/* If the end TRB isn't in this segment, this is set to 0 */
1193 		end_trb_dma = xhci_trb_virt_to_dma(cur_seg, end_trb);
1194 
1195 		if (end_trb_dma > 0) {
1196 			/* The end TRB is in this segment, so suspect should be here */
1197 			if (start_dma <= end_trb_dma) {
1198 				if (suspect_dma >= start_dma && suspect_dma <= end_trb_dma)
1199 					return cur_seg;
1200 			} else {
1201 				/* Case for one segment with
1202 				 * a TD wrapped around to the top
1203 				 */
1204 				if ((suspect_dma >= start_dma &&
1205 							suspect_dma <= end_seg_dma) ||
1206 						(suspect_dma >= cur_seg->dma &&
1207 						 suspect_dma <= end_trb_dma))
1208 					return cur_seg;
1209 			}
1210 			return NULL;
1211 		} else {
1212 			/* Might still be somewhere in this segment */
1213 			if (suspect_dma >= start_dma && suspect_dma <= end_seg_dma)
1214 				return cur_seg;
1215 		}
1216 		cur_seg = cur_seg->next;
1217 		start_dma = xhci_trb_virt_to_dma(cur_seg, &cur_seg->trbs[0]);
1218 	} while (cur_seg != start_seg);
1219 
1220 	return NULL;
1221 }
1222 
1223 static void xhci_cleanup_halted_endpoint(struct xhci_hcd *xhci,
1224 		unsigned int slot_id, unsigned int ep_index,
1225 		unsigned int stream_id,
1226 		struct xhci_td *td, union xhci_trb *event_trb)
1227 {
1228 	struct xhci_virt_ep *ep = &xhci->devs[slot_id]->eps[ep_index];
1229 	ep->ep_state |= EP_HALTED;
1230 	ep->stopped_td = td;
1231 	ep->stopped_trb = event_trb;
1232 	ep->stopped_stream = stream_id;
1233 
1234 	xhci_queue_reset_ep(xhci, slot_id, ep_index);
1235 	xhci_cleanup_stalled_ring(xhci, td->urb->dev, ep_index);
1236 
1237 	ep->stopped_td = NULL;
1238 	ep->stopped_trb = NULL;
1239 	ep->stopped_stream = 0;
1240 
1241 	xhci_ring_cmd_db(xhci);
1242 }
1243 
1244 /* Check if an error has halted the endpoint ring.  The class driver will
1245  * cleanup the halt for a non-default control endpoint if we indicate a stall.
1246  * However, a babble and other errors also halt the endpoint ring, and the class
1247  * driver won't clear the halt in that case, so we need to issue a Set Transfer
1248  * Ring Dequeue Pointer command manually.
1249  */
1250 static int xhci_requires_manual_halt_cleanup(struct xhci_hcd *xhci,
1251 		struct xhci_ep_ctx *ep_ctx,
1252 		unsigned int trb_comp_code)
1253 {
1254 	/* TRB completion codes that may require a manual halt cleanup */
1255 	if (trb_comp_code == COMP_TX_ERR ||
1256 			trb_comp_code == COMP_BABBLE ||
1257 			trb_comp_code == COMP_SPLIT_ERR)
1258 		/* The 0.96 spec says a babbling control endpoint
1259 		 * is not halted. The 0.96 spec says it is.  Some HW
1260 		 * claims to be 0.95 compliant, but it halts the control
1261 		 * endpoint anyway.  Check if a babble halted the
1262 		 * endpoint.
1263 		 */
1264 		if ((ep_ctx->ep_info & EP_STATE_MASK) == EP_STATE_HALTED)
1265 			return 1;
1266 
1267 	return 0;
1268 }
1269 
1270 int xhci_is_vendor_info_code(struct xhci_hcd *xhci, unsigned int trb_comp_code)
1271 {
1272 	if (trb_comp_code >= 224 && trb_comp_code <= 255) {
1273 		/* Vendor defined "informational" completion code,
1274 		 * treat as not-an-error.
1275 		 */
1276 		xhci_dbg(xhci, "Vendor defined info completion code %u\n",
1277 				trb_comp_code);
1278 		xhci_dbg(xhci, "Treating code as success.\n");
1279 		return 1;
1280 	}
1281 	return 0;
1282 }
1283 
1284 /*
1285  * Finish the td processing, remove the td from td list;
1286  * Return 1 if the urb can be given back.
1287  */
1288 static int finish_td(struct xhci_hcd *xhci, struct xhci_td *td,
1289 	union xhci_trb *event_trb, struct xhci_transfer_event *event,
1290 	struct xhci_virt_ep *ep, int *status, bool skip)
1291 {
1292 	struct xhci_virt_device *xdev;
1293 	struct xhci_ring *ep_ring;
1294 	unsigned int slot_id;
1295 	int ep_index;
1296 	struct urb *urb = NULL;
1297 	struct xhci_ep_ctx *ep_ctx;
1298 	int ret = 0;
1299 	struct urb_priv	*urb_priv;
1300 	u32 trb_comp_code;
1301 
1302 	slot_id = TRB_TO_SLOT_ID(event->flags);
1303 	xdev = xhci->devs[slot_id];
1304 	ep_index = TRB_TO_EP_ID(event->flags) - 1;
1305 	ep_ring = xhci_dma_to_transfer_ring(ep, event->buffer);
1306 	ep_ctx = xhci_get_ep_ctx(xhci, xdev->out_ctx, ep_index);
1307 	trb_comp_code = GET_COMP_CODE(event->transfer_len);
1308 
1309 	if (skip)
1310 		goto td_cleanup;
1311 
1312 	if (trb_comp_code == COMP_STOP_INVAL ||
1313 			trb_comp_code == COMP_STOP) {
1314 		/* The Endpoint Stop Command completion will take care of any
1315 		 * stopped TDs.  A stopped TD may be restarted, so don't update
1316 		 * the ring dequeue pointer or take this TD off any lists yet.
1317 		 */
1318 		ep->stopped_td = td;
1319 		ep->stopped_trb = event_trb;
1320 		return 0;
1321 	} else {
1322 		if (trb_comp_code == COMP_STALL) {
1323 			/* The transfer is completed from the driver's
1324 			 * perspective, but we need to issue a set dequeue
1325 			 * command for this stalled endpoint to move the dequeue
1326 			 * pointer past the TD.  We can't do that here because
1327 			 * the halt condition must be cleared first.  Let the
1328 			 * USB class driver clear the stall later.
1329 			 */
1330 			ep->stopped_td = td;
1331 			ep->stopped_trb = event_trb;
1332 			ep->stopped_stream = ep_ring->stream_id;
1333 		} else if (xhci_requires_manual_halt_cleanup(xhci,
1334 					ep_ctx, trb_comp_code)) {
1335 			/* Other types of errors halt the endpoint, but the
1336 			 * class driver doesn't call usb_reset_endpoint() unless
1337 			 * the error is -EPIPE.  Clear the halted status in the
1338 			 * xHCI hardware manually.
1339 			 */
1340 			xhci_cleanup_halted_endpoint(xhci,
1341 					slot_id, ep_index, ep_ring->stream_id,
1342 					td, event_trb);
1343 		} else {
1344 			/* Update ring dequeue pointer */
1345 			while (ep_ring->dequeue != td->last_trb)
1346 				inc_deq(xhci, ep_ring, false);
1347 			inc_deq(xhci, ep_ring, false);
1348 		}
1349 
1350 td_cleanup:
1351 		/* Clean up the endpoint's TD list */
1352 		urb = td->urb;
1353 		urb_priv = urb->hcpriv;
1354 
1355 		/* Do one last check of the actual transfer length.
1356 		 * If the host controller said we transferred more data than
1357 		 * the buffer length, urb->actual_length will be a very big
1358 		 * number (since it's unsigned).  Play it safe and say we didn't
1359 		 * transfer anything.
1360 		 */
1361 		if (urb->actual_length > urb->transfer_buffer_length) {
1362 			xhci_warn(xhci, "URB transfer length is wrong, "
1363 					"xHC issue? req. len = %u, "
1364 					"act. len = %u\n",
1365 					urb->transfer_buffer_length,
1366 					urb->actual_length);
1367 			urb->actual_length = 0;
1368 			if (td->urb->transfer_flags & URB_SHORT_NOT_OK)
1369 				*status = -EREMOTEIO;
1370 			else
1371 				*status = 0;
1372 		}
1373 		list_del(&td->td_list);
1374 		/* Was this TD slated to be cancelled but completed anyway? */
1375 		if (!list_empty(&td->cancelled_td_list))
1376 			list_del(&td->cancelled_td_list);
1377 
1378 		urb_priv->td_cnt++;
1379 		/* Giveback the urb when all the tds are completed */
1380 		if (urb_priv->td_cnt == urb_priv->length)
1381 			ret = 1;
1382 	}
1383 
1384 	return ret;
1385 }
1386 
1387 /*
1388  * Process control tds, update urb status and actual_length.
1389  */
1390 static int process_ctrl_td(struct xhci_hcd *xhci, struct xhci_td *td,
1391 	union xhci_trb *event_trb, struct xhci_transfer_event *event,
1392 	struct xhci_virt_ep *ep, int *status)
1393 {
1394 	struct xhci_virt_device *xdev;
1395 	struct xhci_ring *ep_ring;
1396 	unsigned int slot_id;
1397 	int ep_index;
1398 	struct xhci_ep_ctx *ep_ctx;
1399 	u32 trb_comp_code;
1400 
1401 	slot_id = TRB_TO_SLOT_ID(event->flags);
1402 	xdev = xhci->devs[slot_id];
1403 	ep_index = TRB_TO_EP_ID(event->flags) - 1;
1404 	ep_ring = xhci_dma_to_transfer_ring(ep, event->buffer);
1405 	ep_ctx = xhci_get_ep_ctx(xhci, xdev->out_ctx, ep_index);
1406 	trb_comp_code = GET_COMP_CODE(event->transfer_len);
1407 
1408 	xhci_debug_trb(xhci, xhci->event_ring->dequeue);
1409 	switch (trb_comp_code) {
1410 	case COMP_SUCCESS:
1411 		if (event_trb == ep_ring->dequeue) {
1412 			xhci_warn(xhci, "WARN: Success on ctrl setup TRB "
1413 					"without IOC set??\n");
1414 			*status = -ESHUTDOWN;
1415 		} else if (event_trb != td->last_trb) {
1416 			xhci_warn(xhci, "WARN: Success on ctrl data TRB "
1417 					"without IOC set??\n");
1418 			*status = -ESHUTDOWN;
1419 		} else {
1420 			xhci_dbg(xhci, "Successful control transfer!\n");
1421 			*status = 0;
1422 		}
1423 		break;
1424 	case COMP_SHORT_TX:
1425 		xhci_warn(xhci, "WARN: short transfer on control ep\n");
1426 		if (td->urb->transfer_flags & URB_SHORT_NOT_OK)
1427 			*status = -EREMOTEIO;
1428 		else
1429 			*status = 0;
1430 		break;
1431 	default:
1432 		if (!xhci_requires_manual_halt_cleanup(xhci,
1433 					ep_ctx, trb_comp_code))
1434 			break;
1435 		xhci_dbg(xhci, "TRB error code %u, "
1436 				"halted endpoint index = %u\n",
1437 				trb_comp_code, ep_index);
1438 		/* else fall through */
1439 	case COMP_STALL:
1440 		/* Did we transfer part of the data (middle) phase? */
1441 		if (event_trb != ep_ring->dequeue &&
1442 				event_trb != td->last_trb)
1443 			td->urb->actual_length =
1444 				td->urb->transfer_buffer_length
1445 				- TRB_LEN(event->transfer_len);
1446 		else
1447 			td->urb->actual_length = 0;
1448 
1449 		xhci_cleanup_halted_endpoint(xhci,
1450 			slot_id, ep_index, 0, td, event_trb);
1451 		return finish_td(xhci, td, event_trb, event, ep, status, true);
1452 	}
1453 	/*
1454 	 * Did we transfer any data, despite the errors that might have
1455 	 * happened?  I.e. did we get past the setup stage?
1456 	 */
1457 	if (event_trb != ep_ring->dequeue) {
1458 		/* The event was for the status stage */
1459 		if (event_trb == td->last_trb) {
1460 			if (td->urb->actual_length != 0) {
1461 				/* Don't overwrite a previously set error code
1462 				 */
1463 				if ((*status == -EINPROGRESS || *status == 0) &&
1464 						(td->urb->transfer_flags
1465 						 & URB_SHORT_NOT_OK))
1466 					/* Did we already see a short data
1467 					 * stage? */
1468 					*status = -EREMOTEIO;
1469 			} else {
1470 				td->urb->actual_length =
1471 					td->urb->transfer_buffer_length;
1472 			}
1473 		} else {
1474 		/* Maybe the event was for the data stage? */
1475 			if (trb_comp_code != COMP_STOP_INVAL) {
1476 				/* We didn't stop on a link TRB in the middle */
1477 				td->urb->actual_length =
1478 					td->urb->transfer_buffer_length -
1479 					TRB_LEN(event->transfer_len);
1480 				xhci_dbg(xhci, "Waiting for status "
1481 						"stage event\n");
1482 				return 0;
1483 			}
1484 		}
1485 	}
1486 
1487 	return finish_td(xhci, td, event_trb, event, ep, status, false);
1488 }
1489 
1490 /*
1491  * Process isochronous tds, update urb packet status and actual_length.
1492  */
1493 static int process_isoc_td(struct xhci_hcd *xhci, struct xhci_td *td,
1494 	union xhci_trb *event_trb, struct xhci_transfer_event *event,
1495 	struct xhci_virt_ep *ep, int *status)
1496 {
1497 	struct xhci_ring *ep_ring;
1498 	struct urb_priv *urb_priv;
1499 	int idx;
1500 	int len = 0;
1501 	int skip_td = 0;
1502 	union xhci_trb *cur_trb;
1503 	struct xhci_segment *cur_seg;
1504 	u32 trb_comp_code;
1505 
1506 	ep_ring = xhci_dma_to_transfer_ring(ep, event->buffer);
1507 	trb_comp_code = GET_COMP_CODE(event->transfer_len);
1508 	urb_priv = td->urb->hcpriv;
1509 	idx = urb_priv->td_cnt;
1510 
1511 	if (ep->skip) {
1512 		/* The transfer is partly done */
1513 		*status = -EXDEV;
1514 		td->urb->iso_frame_desc[idx].status = -EXDEV;
1515 	} else {
1516 		/* handle completion code */
1517 		switch (trb_comp_code) {
1518 		case COMP_SUCCESS:
1519 			td->urb->iso_frame_desc[idx].status = 0;
1520 			xhci_dbg(xhci, "Successful isoc transfer!\n");
1521 			break;
1522 		case COMP_SHORT_TX:
1523 			if (td->urb->transfer_flags & URB_SHORT_NOT_OK)
1524 				td->urb->iso_frame_desc[idx].status =
1525 					 -EREMOTEIO;
1526 			else
1527 				td->urb->iso_frame_desc[idx].status = 0;
1528 			break;
1529 		case COMP_BW_OVER:
1530 			td->urb->iso_frame_desc[idx].status = -ECOMM;
1531 			skip_td = 1;
1532 			break;
1533 		case COMP_BUFF_OVER:
1534 		case COMP_BABBLE:
1535 			td->urb->iso_frame_desc[idx].status = -EOVERFLOW;
1536 			skip_td = 1;
1537 			break;
1538 		case COMP_STALL:
1539 			td->urb->iso_frame_desc[idx].status = -EPROTO;
1540 			skip_td = 1;
1541 			break;
1542 		case COMP_STOP:
1543 		case COMP_STOP_INVAL:
1544 			break;
1545 		default:
1546 			td->urb->iso_frame_desc[idx].status = -1;
1547 			break;
1548 		}
1549 	}
1550 
1551 	/* calc actual length */
1552 	if (ep->skip) {
1553 		td->urb->iso_frame_desc[idx].actual_length = 0;
1554 		return finish_td(xhci, td, event_trb, event, ep, status, true);
1555 	}
1556 
1557 	if (trb_comp_code == COMP_SUCCESS || skip_td == 1) {
1558 		td->urb->iso_frame_desc[idx].actual_length =
1559 			td->urb->iso_frame_desc[idx].length;
1560 		td->urb->actual_length +=
1561 			td->urb->iso_frame_desc[idx].length;
1562 	} else {
1563 		for (cur_trb = ep_ring->dequeue,
1564 		     cur_seg = ep_ring->deq_seg; cur_trb != event_trb;
1565 		     next_trb(xhci, ep_ring, &cur_seg, &cur_trb)) {
1566 			if ((cur_trb->generic.field[3] &
1567 			 TRB_TYPE_BITMASK) != TRB_TYPE(TRB_TR_NOOP) &&
1568 			    (cur_trb->generic.field[3] &
1569 			 TRB_TYPE_BITMASK) != TRB_TYPE(TRB_LINK))
1570 				len +=
1571 				    TRB_LEN(cur_trb->generic.field[2]);
1572 		}
1573 		len += TRB_LEN(cur_trb->generic.field[2]) -
1574 			TRB_LEN(event->transfer_len);
1575 
1576 		if (trb_comp_code != COMP_STOP_INVAL) {
1577 			td->urb->iso_frame_desc[idx].actual_length = len;
1578 			td->urb->actual_length += len;
1579 		}
1580 	}
1581 
1582 	if ((idx == urb_priv->length - 1) && *status == -EINPROGRESS)
1583 		*status = 0;
1584 
1585 	return finish_td(xhci, td, event_trb, event, ep, status, false);
1586 }
1587 
1588 /*
1589  * Process bulk and interrupt tds, update urb status and actual_length.
1590  */
1591 static int process_bulk_intr_td(struct xhci_hcd *xhci, struct xhci_td *td,
1592 	union xhci_trb *event_trb, struct xhci_transfer_event *event,
1593 	struct xhci_virt_ep *ep, int *status)
1594 {
1595 	struct xhci_ring *ep_ring;
1596 	union xhci_trb *cur_trb;
1597 	struct xhci_segment *cur_seg;
1598 	u32 trb_comp_code;
1599 
1600 	ep_ring = xhci_dma_to_transfer_ring(ep, event->buffer);
1601 	trb_comp_code = GET_COMP_CODE(event->transfer_len);
1602 
1603 	switch (trb_comp_code) {
1604 	case COMP_SUCCESS:
1605 		/* Double check that the HW transferred everything. */
1606 		if (event_trb != td->last_trb) {
1607 			xhci_warn(xhci, "WARN Successful completion "
1608 					"on short TX\n");
1609 			if (td->urb->transfer_flags & URB_SHORT_NOT_OK)
1610 				*status = -EREMOTEIO;
1611 			else
1612 				*status = 0;
1613 		} else {
1614 			if (usb_endpoint_xfer_bulk(&td->urb->ep->desc))
1615 				xhci_dbg(xhci, "Successful bulk "
1616 						"transfer!\n");
1617 			else
1618 				xhci_dbg(xhci, "Successful interrupt "
1619 						"transfer!\n");
1620 			*status = 0;
1621 		}
1622 		break;
1623 	case COMP_SHORT_TX:
1624 		if (td->urb->transfer_flags & URB_SHORT_NOT_OK)
1625 			*status = -EREMOTEIO;
1626 		else
1627 			*status = 0;
1628 		break;
1629 	default:
1630 		/* Others already handled above */
1631 		break;
1632 	}
1633 	dev_dbg(&td->urb->dev->dev,
1634 			"ep %#x - asked for %d bytes, "
1635 			"%d bytes untransferred\n",
1636 			td->urb->ep->desc.bEndpointAddress,
1637 			td->urb->transfer_buffer_length,
1638 			TRB_LEN(event->transfer_len));
1639 	/* Fast path - was this the last TRB in the TD for this URB? */
1640 	if (event_trb == td->last_trb) {
1641 		if (TRB_LEN(event->transfer_len) != 0) {
1642 			td->urb->actual_length =
1643 				td->urb->transfer_buffer_length -
1644 				TRB_LEN(event->transfer_len);
1645 			if (td->urb->transfer_buffer_length <
1646 					td->urb->actual_length) {
1647 				xhci_warn(xhci, "HC gave bad length "
1648 						"of %d bytes left\n",
1649 						TRB_LEN(event->transfer_len));
1650 				td->urb->actual_length = 0;
1651 				if (td->urb->transfer_flags & URB_SHORT_NOT_OK)
1652 					*status = -EREMOTEIO;
1653 				else
1654 					*status = 0;
1655 			}
1656 			/* Don't overwrite a previously set error code */
1657 			if (*status == -EINPROGRESS) {
1658 				if (td->urb->transfer_flags & URB_SHORT_NOT_OK)
1659 					*status = -EREMOTEIO;
1660 				else
1661 					*status = 0;
1662 			}
1663 		} else {
1664 			td->urb->actual_length =
1665 				td->urb->transfer_buffer_length;
1666 			/* Ignore a short packet completion if the
1667 			 * untransferred length was zero.
1668 			 */
1669 			if (*status == -EREMOTEIO)
1670 				*status = 0;
1671 		}
1672 	} else {
1673 		/* Slow path - walk the list, starting from the dequeue
1674 		 * pointer, to get the actual length transferred.
1675 		 */
1676 		td->urb->actual_length = 0;
1677 		for (cur_trb = ep_ring->dequeue, cur_seg = ep_ring->deq_seg;
1678 				cur_trb != event_trb;
1679 				next_trb(xhci, ep_ring, &cur_seg, &cur_trb)) {
1680 			if ((cur_trb->generic.field[3] &
1681 			 TRB_TYPE_BITMASK) != TRB_TYPE(TRB_TR_NOOP) &&
1682 			    (cur_trb->generic.field[3] &
1683 			 TRB_TYPE_BITMASK) != TRB_TYPE(TRB_LINK))
1684 				td->urb->actual_length +=
1685 					TRB_LEN(cur_trb->generic.field[2]);
1686 		}
1687 		/* If the ring didn't stop on a Link or No-op TRB, add
1688 		 * in the actual bytes transferred from the Normal TRB
1689 		 */
1690 		if (trb_comp_code != COMP_STOP_INVAL)
1691 			td->urb->actual_length +=
1692 				TRB_LEN(cur_trb->generic.field[2]) -
1693 				TRB_LEN(event->transfer_len);
1694 	}
1695 
1696 	return finish_td(xhci, td, event_trb, event, ep, status, false);
1697 }
1698 
1699 /*
1700  * If this function returns an error condition, it means it got a Transfer
1701  * event with a corrupted Slot ID, Endpoint ID, or TRB DMA address.
1702  * At this point, the host controller is probably hosed and should be reset.
1703  */
1704 static int handle_tx_event(struct xhci_hcd *xhci,
1705 		struct xhci_transfer_event *event)
1706 {
1707 	struct xhci_virt_device *xdev;
1708 	struct xhci_virt_ep *ep;
1709 	struct xhci_ring *ep_ring;
1710 	unsigned int slot_id;
1711 	int ep_index;
1712 	struct xhci_td *td = NULL;
1713 	dma_addr_t event_dma;
1714 	struct xhci_segment *event_seg;
1715 	union xhci_trb *event_trb;
1716 	struct urb *urb = NULL;
1717 	int status = -EINPROGRESS;
1718 	struct urb_priv *urb_priv;
1719 	struct xhci_ep_ctx *ep_ctx;
1720 	u32 trb_comp_code;
1721 	int ret = 0;
1722 
1723 	slot_id = TRB_TO_SLOT_ID(event->flags);
1724 	xdev = xhci->devs[slot_id];
1725 	if (!xdev) {
1726 		xhci_err(xhci, "ERROR Transfer event pointed to bad slot\n");
1727 		return -ENODEV;
1728 	}
1729 
1730 	/* Endpoint ID is 1 based, our index is zero based */
1731 	ep_index = TRB_TO_EP_ID(event->flags) - 1;
1732 	xhci_dbg(xhci, "%s - ep index = %d\n", __func__, ep_index);
1733 	ep = &xdev->eps[ep_index];
1734 	ep_ring = xhci_dma_to_transfer_ring(ep, event->buffer);
1735 	ep_ctx = xhci_get_ep_ctx(xhci, xdev->out_ctx, ep_index);
1736 	if (!ep_ring ||
1737 		(ep_ctx->ep_info & EP_STATE_MASK) == EP_STATE_DISABLED) {
1738 		xhci_err(xhci, "ERROR Transfer event for disabled endpoint "
1739 				"or incorrect stream ring\n");
1740 		return -ENODEV;
1741 	}
1742 
1743 	event_dma = event->buffer;
1744 	trb_comp_code = GET_COMP_CODE(event->transfer_len);
1745 	/* Look for common error cases */
1746 	switch (trb_comp_code) {
1747 	/* Skip codes that require special handling depending on
1748 	 * transfer type
1749 	 */
1750 	case COMP_SUCCESS:
1751 	case COMP_SHORT_TX:
1752 		break;
1753 	case COMP_STOP:
1754 		xhci_dbg(xhci, "Stopped on Transfer TRB\n");
1755 		break;
1756 	case COMP_STOP_INVAL:
1757 		xhci_dbg(xhci, "Stopped on No-op or Link TRB\n");
1758 		break;
1759 	case COMP_STALL:
1760 		xhci_warn(xhci, "WARN: Stalled endpoint\n");
1761 		ep->ep_state |= EP_HALTED;
1762 		status = -EPIPE;
1763 		break;
1764 	case COMP_TRB_ERR:
1765 		xhci_warn(xhci, "WARN: TRB error on endpoint\n");
1766 		status = -EILSEQ;
1767 		break;
1768 	case COMP_SPLIT_ERR:
1769 	case COMP_TX_ERR:
1770 		xhci_warn(xhci, "WARN: transfer error on endpoint\n");
1771 		status = -EPROTO;
1772 		break;
1773 	case COMP_BABBLE:
1774 		xhci_warn(xhci, "WARN: babble error on endpoint\n");
1775 		status = -EOVERFLOW;
1776 		break;
1777 	case COMP_DB_ERR:
1778 		xhci_warn(xhci, "WARN: HC couldn't access mem fast enough\n");
1779 		status = -ENOSR;
1780 		break;
1781 	case COMP_BW_OVER:
1782 		xhci_warn(xhci, "WARN: bandwidth overrun event on endpoint\n");
1783 		break;
1784 	case COMP_BUFF_OVER:
1785 		xhci_warn(xhci, "WARN: buffer overrun event on endpoint\n");
1786 		break;
1787 	case COMP_UNDERRUN:
1788 		/*
1789 		 * When the Isoch ring is empty, the xHC will generate
1790 		 * a Ring Overrun Event for IN Isoch endpoint or Ring
1791 		 * Underrun Event for OUT Isoch endpoint.
1792 		 */
1793 		xhci_dbg(xhci, "underrun event on endpoint\n");
1794 		if (!list_empty(&ep_ring->td_list))
1795 			xhci_dbg(xhci, "Underrun Event for slot %d ep %d "
1796 					"still with TDs queued?\n",
1797 				TRB_TO_SLOT_ID(event->flags), ep_index);
1798 		goto cleanup;
1799 	case COMP_OVERRUN:
1800 		xhci_dbg(xhci, "overrun event on endpoint\n");
1801 		if (!list_empty(&ep_ring->td_list))
1802 			xhci_dbg(xhci, "Overrun Event for slot %d ep %d "
1803 					"still with TDs queued?\n",
1804 				TRB_TO_SLOT_ID(event->flags), ep_index);
1805 		goto cleanup;
1806 	case COMP_MISSED_INT:
1807 		/*
1808 		 * When encounter missed service error, one or more isoc tds
1809 		 * may be missed by xHC.
1810 		 * Set skip flag of the ep_ring; Complete the missed tds as
1811 		 * short transfer when process the ep_ring next time.
1812 		 */
1813 		ep->skip = true;
1814 		xhci_dbg(xhci, "Miss service interval error, set skip flag\n");
1815 		goto cleanup;
1816 	default:
1817 		if (xhci_is_vendor_info_code(xhci, trb_comp_code)) {
1818 			status = 0;
1819 			break;
1820 		}
1821 		xhci_warn(xhci, "ERROR Unknown event condition, HC probably "
1822 				"busted\n");
1823 		goto cleanup;
1824 	}
1825 
1826 	do {
1827 		/* This TRB should be in the TD at the head of this ring's
1828 		 * TD list.
1829 		 */
1830 		if (list_empty(&ep_ring->td_list)) {
1831 			xhci_warn(xhci, "WARN Event TRB for slot %d ep %d "
1832 					"with no TDs queued?\n",
1833 				  TRB_TO_SLOT_ID(event->flags), ep_index);
1834 			xhci_dbg(xhci, "Event TRB with TRB type ID %u\n",
1835 			  (unsigned int) (event->flags & TRB_TYPE_BITMASK)>>10);
1836 			xhci_print_trb_offsets(xhci, (union xhci_trb *) event);
1837 			if (ep->skip) {
1838 				ep->skip = false;
1839 				xhci_dbg(xhci, "td_list is empty while skip "
1840 						"flag set. Clear skip flag.\n");
1841 			}
1842 			ret = 0;
1843 			goto cleanup;
1844 		}
1845 
1846 		td = list_entry(ep_ring->td_list.next, struct xhci_td, td_list);
1847 		/* Is this a TRB in the currently executing TD? */
1848 		event_seg = trb_in_td(ep_ring->deq_seg, ep_ring->dequeue,
1849 				td->last_trb, event_dma);
1850 		if (event_seg && ep->skip) {
1851 			xhci_dbg(xhci, "Found td. Clear skip flag.\n");
1852 			ep->skip = false;
1853 		}
1854 		if (!event_seg &&
1855 		   (!ep->skip || !usb_endpoint_xfer_isoc(&td->urb->ep->desc))) {
1856 			/* HC is busted, give up! */
1857 			xhci_err(xhci, "ERROR Transfer event TRB DMA ptr not "
1858 					"part of current TD\n");
1859 			return -ESHUTDOWN;
1860 		}
1861 
1862 		if (event_seg) {
1863 			event_trb = &event_seg->trbs[(event_dma -
1864 					 event_seg->dma) / sizeof(*event_trb)];
1865 			/*
1866 			 * No-op TRB should not trigger interrupts.
1867 			 * If event_trb is a no-op TRB, it means the
1868 			 * corresponding TD has been cancelled. Just ignore
1869 			 * the TD.
1870 			 */
1871 			if ((event_trb->generic.field[3] & TRB_TYPE_BITMASK)
1872 					 == TRB_TYPE(TRB_TR_NOOP)) {
1873 				xhci_dbg(xhci, "event_trb is a no-op TRB. "
1874 						"Skip it\n");
1875 				goto cleanup;
1876 			}
1877 		}
1878 
1879 		/* Now update the urb's actual_length and give back to
1880 		 * the core
1881 		 */
1882 		if (usb_endpoint_xfer_control(&td->urb->ep->desc))
1883 			ret = process_ctrl_td(xhci, td, event_trb, event, ep,
1884 						 &status);
1885 		else if (usb_endpoint_xfer_isoc(&td->urb->ep->desc))
1886 			ret = process_isoc_td(xhci, td, event_trb, event, ep,
1887 						 &status);
1888 		else
1889 			ret = process_bulk_intr_td(xhci, td, event_trb, event,
1890 						 ep, &status);
1891 
1892 cleanup:
1893 		/*
1894 		 * Do not update event ring dequeue pointer if ep->skip is set.
1895 		 * Will roll back to continue process missed tds.
1896 		 */
1897 		if (trb_comp_code == COMP_MISSED_INT || !ep->skip) {
1898 			inc_deq(xhci, xhci->event_ring, true);
1899 		}
1900 
1901 		if (ret) {
1902 			urb = td->urb;
1903 			urb_priv = urb->hcpriv;
1904 			/* Leave the TD around for the reset endpoint function
1905 			 * to use(but only if it's not a control endpoint,
1906 			 * since we already queued the Set TR dequeue pointer
1907 			 * command for stalled control endpoints).
1908 			 */
1909 			if (usb_endpoint_xfer_control(&urb->ep->desc) ||
1910 				(trb_comp_code != COMP_STALL &&
1911 					trb_comp_code != COMP_BABBLE))
1912 				xhci_urb_free_priv(xhci, urb_priv);
1913 
1914 			usb_hcd_unlink_urb_from_ep(xhci_to_hcd(xhci), urb);
1915 			xhci_dbg(xhci, "Giveback URB %p, len = %d, "
1916 					"status = %d\n",
1917 					urb, urb->actual_length, status);
1918 			spin_unlock(&xhci->lock);
1919 			usb_hcd_giveback_urb(xhci_to_hcd(xhci), urb, status);
1920 			spin_lock(&xhci->lock);
1921 		}
1922 
1923 	/*
1924 	 * If ep->skip is set, it means there are missed tds on the
1925 	 * endpoint ring need to take care of.
1926 	 * Process them as short transfer until reach the td pointed by
1927 	 * the event.
1928 	 */
1929 	} while (ep->skip && trb_comp_code != COMP_MISSED_INT);
1930 
1931 	return 0;
1932 }
1933 
1934 /*
1935  * This function handles all OS-owned events on the event ring.  It may drop
1936  * xhci->lock between event processing (e.g. to pass up port status changes).
1937  */
1938 static void xhci_handle_event(struct xhci_hcd *xhci)
1939 {
1940 	union xhci_trb *event;
1941 	int update_ptrs = 1;
1942 	int ret;
1943 
1944 	xhci_dbg(xhci, "In %s\n", __func__);
1945 	if (!xhci->event_ring || !xhci->event_ring->dequeue) {
1946 		xhci->error_bitmask |= 1 << 1;
1947 		return;
1948 	}
1949 
1950 	event = xhci->event_ring->dequeue;
1951 	/* Does the HC or OS own the TRB? */
1952 	if ((event->event_cmd.flags & TRB_CYCLE) !=
1953 			xhci->event_ring->cycle_state) {
1954 		xhci->error_bitmask |= 1 << 2;
1955 		return;
1956 	}
1957 	xhci_dbg(xhci, "%s - OS owns TRB\n", __func__);
1958 
1959 	/* FIXME: Handle more event types. */
1960 	switch ((event->event_cmd.flags & TRB_TYPE_BITMASK)) {
1961 	case TRB_TYPE(TRB_COMPLETION):
1962 		xhci_dbg(xhci, "%s - calling handle_cmd_completion\n", __func__);
1963 		handle_cmd_completion(xhci, &event->event_cmd);
1964 		xhci_dbg(xhci, "%s - returned from handle_cmd_completion\n", __func__);
1965 		break;
1966 	case TRB_TYPE(TRB_PORT_STATUS):
1967 		xhci_dbg(xhci, "%s - calling handle_port_status\n", __func__);
1968 		handle_port_status(xhci, event);
1969 		xhci_dbg(xhci, "%s - returned from handle_port_status\n", __func__);
1970 		update_ptrs = 0;
1971 		break;
1972 	case TRB_TYPE(TRB_TRANSFER):
1973 		xhci_dbg(xhci, "%s - calling handle_tx_event\n", __func__);
1974 		ret = handle_tx_event(xhci, &event->trans_event);
1975 		xhci_dbg(xhci, "%s - returned from handle_tx_event\n", __func__);
1976 		if (ret < 0)
1977 			xhci->error_bitmask |= 1 << 9;
1978 		else
1979 			update_ptrs = 0;
1980 		break;
1981 	default:
1982 		if ((event->event_cmd.flags & TRB_TYPE_BITMASK) >= TRB_TYPE(48))
1983 			handle_vendor_event(xhci, event);
1984 		else
1985 			xhci->error_bitmask |= 1 << 3;
1986 	}
1987 	/* Any of the above functions may drop and re-acquire the lock, so check
1988 	 * to make sure a watchdog timer didn't mark the host as non-responsive.
1989 	 */
1990 	if (xhci->xhc_state & XHCI_STATE_DYING) {
1991 		xhci_dbg(xhci, "xHCI host dying, returning from "
1992 				"event handler.\n");
1993 		return;
1994 	}
1995 
1996 	if (update_ptrs)
1997 		/* Update SW event ring dequeue pointer */
1998 		inc_deq(xhci, xhci->event_ring, true);
1999 
2000 	/* Are there more items on the event ring? */
2001 	xhci_handle_event(xhci);
2002 }
2003 
2004 /*
2005  * xHCI spec says we can get an interrupt, and if the HC has an error condition,
2006  * we might get bad data out of the event ring.  Section 4.10.2.7 has a list of
2007  * indicators of an event TRB error, but we check the status *first* to be safe.
2008  */
2009 irqreturn_t xhci_irq(struct usb_hcd *hcd)
2010 {
2011 	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
2012 	u32 status;
2013 	union xhci_trb *trb;
2014 	u64 temp_64;
2015 	union xhci_trb *event_ring_deq;
2016 	dma_addr_t deq;
2017 
2018 	spin_lock(&xhci->lock);
2019 	trb = xhci->event_ring->dequeue;
2020 	/* Check if the xHC generated the interrupt, or the irq is shared */
2021 	status = xhci_readl(xhci, &xhci->op_regs->status);
2022 	if (status == 0xffffffff)
2023 		goto hw_died;
2024 
2025 	if (!(status & STS_EINT)) {
2026 		spin_unlock(&xhci->lock);
2027 		xhci_warn(xhci, "Spurious interrupt.\n");
2028 		return IRQ_NONE;
2029 	}
2030 	xhci_dbg(xhci, "op reg status = %08x\n", status);
2031 	xhci_dbg(xhci, "Event ring dequeue ptr:\n");
2032 	xhci_dbg(xhci, "@%llx %08x %08x %08x %08x\n",
2033 			(unsigned long long)
2034 			xhci_trb_virt_to_dma(xhci->event_ring->deq_seg, trb),
2035 			lower_32_bits(trb->link.segment_ptr),
2036 			upper_32_bits(trb->link.segment_ptr),
2037 			(unsigned int) trb->link.intr_target,
2038 			(unsigned int) trb->link.control);
2039 
2040 	if (status & STS_FATAL) {
2041 		xhci_warn(xhci, "WARNING: Host System Error\n");
2042 		xhci_halt(xhci);
2043 hw_died:
2044 		xhci_to_hcd(xhci)->state = HC_STATE_HALT;
2045 		spin_unlock(&xhci->lock);
2046 		return -ESHUTDOWN;
2047 	}
2048 
2049 	/*
2050 	 * Clear the op reg interrupt status first,
2051 	 * so we can receive interrupts from other MSI-X interrupters.
2052 	 * Write 1 to clear the interrupt status.
2053 	 */
2054 	status |= STS_EINT;
2055 	xhci_writel(xhci, status, &xhci->op_regs->status);
2056 	/* FIXME when MSI-X is supported and there are multiple vectors */
2057 	/* Clear the MSI-X event interrupt status */
2058 
2059 	if (hcd->irq != -1) {
2060 		u32 irq_pending;
2061 		/* Acknowledge the PCI interrupt */
2062 		irq_pending = xhci_readl(xhci, &xhci->ir_set->irq_pending);
2063 		irq_pending |= 0x3;
2064 		xhci_writel(xhci, irq_pending, &xhci->ir_set->irq_pending);
2065 	}
2066 
2067 	if (xhci->xhc_state & XHCI_STATE_DYING) {
2068 		xhci_dbg(xhci, "xHCI dying, ignoring interrupt. "
2069 				"Shouldn't IRQs be disabled?\n");
2070 		/* Clear the event handler busy flag (RW1C);
2071 		 * the event ring should be empty.
2072 		 */
2073 		temp_64 = xhci_read_64(xhci, &xhci->ir_set->erst_dequeue);
2074 		xhci_write_64(xhci, temp_64 | ERST_EHB,
2075 				&xhci->ir_set->erst_dequeue);
2076 		spin_unlock(&xhci->lock);
2077 
2078 		return IRQ_HANDLED;
2079 	}
2080 
2081 	event_ring_deq = xhci->event_ring->dequeue;
2082 	/* FIXME this should be a delayed service routine
2083 	 * that clears the EHB.
2084 	 */
2085 	xhci_handle_event(xhci);
2086 
2087 	temp_64 = xhci_read_64(xhci, &xhci->ir_set->erst_dequeue);
2088 	/* If necessary, update the HW's version of the event ring deq ptr. */
2089 	if (event_ring_deq != xhci->event_ring->dequeue) {
2090 		deq = xhci_trb_virt_to_dma(xhci->event_ring->deq_seg,
2091 				xhci->event_ring->dequeue);
2092 		if (deq == 0)
2093 			xhci_warn(xhci, "WARN something wrong with SW event "
2094 					"ring dequeue ptr.\n");
2095 		/* Update HC event ring dequeue pointer */
2096 		temp_64 &= ERST_PTR_MASK;
2097 		temp_64 |= ((u64) deq & (u64) ~ERST_PTR_MASK);
2098 	}
2099 
2100 	/* Clear the event handler busy flag (RW1C); event ring is empty. */
2101 	temp_64 |= ERST_EHB;
2102 	xhci_write_64(xhci, temp_64, &xhci->ir_set->erst_dequeue);
2103 
2104 	spin_unlock(&xhci->lock);
2105 
2106 	return IRQ_HANDLED;
2107 }
2108 
2109 irqreturn_t xhci_msi_irq(int irq, struct usb_hcd *hcd)
2110 {
2111 	irqreturn_t ret;
2112 
2113 	set_bit(HCD_FLAG_SAW_IRQ, &hcd->flags);
2114 
2115 	ret = xhci_irq(hcd);
2116 
2117 	return ret;
2118 }
2119 
2120 /****		Endpoint Ring Operations	****/
2121 
2122 /*
2123  * Generic function for queueing a TRB on a ring.
2124  * The caller must have checked to make sure there's room on the ring.
2125  *
2126  * @more_trbs_coming:	Will you enqueue more TRBs before calling
2127  *			prepare_transfer()?
2128  */
2129 static void queue_trb(struct xhci_hcd *xhci, struct xhci_ring *ring,
2130 		bool consumer, bool more_trbs_coming,
2131 		u32 field1, u32 field2, u32 field3, u32 field4)
2132 {
2133 	struct xhci_generic_trb *trb;
2134 
2135 	trb = &ring->enqueue->generic;
2136 	trb->field[0] = field1;
2137 	trb->field[1] = field2;
2138 	trb->field[2] = field3;
2139 	trb->field[3] = field4;
2140 	inc_enq(xhci, ring, consumer, more_trbs_coming);
2141 }
2142 
2143 /*
2144  * Does various checks on the endpoint ring, and makes it ready to queue num_trbs.
2145  * FIXME allocate segments if the ring is full.
2146  */
2147 static int prepare_ring(struct xhci_hcd *xhci, struct xhci_ring *ep_ring,
2148 		u32 ep_state, unsigned int num_trbs, gfp_t mem_flags)
2149 {
2150 	/* Make sure the endpoint has been added to xHC schedule */
2151 	xhci_dbg(xhci, "Endpoint state = 0x%x\n", ep_state);
2152 	switch (ep_state) {
2153 	case EP_STATE_DISABLED:
2154 		/*
2155 		 * USB core changed config/interfaces without notifying us,
2156 		 * or hardware is reporting the wrong state.
2157 		 */
2158 		xhci_warn(xhci, "WARN urb submitted to disabled ep\n");
2159 		return -ENOENT;
2160 	case EP_STATE_ERROR:
2161 		xhci_warn(xhci, "WARN waiting for error on ep to be cleared\n");
2162 		/* FIXME event handling code for error needs to clear it */
2163 		/* XXX not sure if this should be -ENOENT or not */
2164 		return -EINVAL;
2165 	case EP_STATE_HALTED:
2166 		xhci_dbg(xhci, "WARN halted endpoint, queueing URB anyway.\n");
2167 	case EP_STATE_STOPPED:
2168 	case EP_STATE_RUNNING:
2169 		break;
2170 	default:
2171 		xhci_err(xhci, "ERROR unknown endpoint state for ep\n");
2172 		/*
2173 		 * FIXME issue Configure Endpoint command to try to get the HC
2174 		 * back into a known state.
2175 		 */
2176 		return -EINVAL;
2177 	}
2178 	if (!room_on_ring(xhci, ep_ring, num_trbs)) {
2179 		/* FIXME allocate more room */
2180 		xhci_err(xhci, "ERROR no room on ep ring\n");
2181 		return -ENOMEM;
2182 	}
2183 
2184 	if (enqueue_is_link_trb(ep_ring)) {
2185 		struct xhci_ring *ring = ep_ring;
2186 		union xhci_trb *next;
2187 
2188 		xhci_dbg(xhci, "prepare_ring: pointing to link trb\n");
2189 		next = ring->enqueue;
2190 
2191 		while (last_trb(xhci, ring, ring->enq_seg, next)) {
2192 
2193 			/* If we're not dealing with 0.95 hardware,
2194 			 * clear the chain bit.
2195 			 */
2196 			if (!xhci_link_trb_quirk(xhci))
2197 				next->link.control &= ~TRB_CHAIN;
2198 			else
2199 				next->link.control |= TRB_CHAIN;
2200 
2201 			wmb();
2202 			next->link.control ^= (u32) TRB_CYCLE;
2203 
2204 			/* Toggle the cycle bit after the last ring segment. */
2205 			if (last_trb_on_last_seg(xhci, ring, ring->enq_seg, next)) {
2206 				ring->cycle_state = (ring->cycle_state ? 0 : 1);
2207 				if (!in_interrupt()) {
2208 					xhci_dbg(xhci, "queue_trb: Toggle cycle "
2209 						"state for ring %p = %i\n",
2210 						ring, (unsigned int)ring->cycle_state);
2211 				}
2212 			}
2213 			ring->enq_seg = ring->enq_seg->next;
2214 			ring->enqueue = ring->enq_seg->trbs;
2215 			next = ring->enqueue;
2216 		}
2217 	}
2218 
2219 	return 0;
2220 }
2221 
2222 static int prepare_transfer(struct xhci_hcd *xhci,
2223 		struct xhci_virt_device *xdev,
2224 		unsigned int ep_index,
2225 		unsigned int stream_id,
2226 		unsigned int num_trbs,
2227 		struct urb *urb,
2228 		unsigned int td_index,
2229 		gfp_t mem_flags)
2230 {
2231 	int ret;
2232 	struct urb_priv *urb_priv;
2233 	struct xhci_td	*td;
2234 	struct xhci_ring *ep_ring;
2235 	struct xhci_ep_ctx *ep_ctx = xhci_get_ep_ctx(xhci, xdev->out_ctx, ep_index);
2236 
2237 	ep_ring = xhci_stream_id_to_ring(xdev, ep_index, stream_id);
2238 	if (!ep_ring) {
2239 		xhci_dbg(xhci, "Can't prepare ring for bad stream ID %u\n",
2240 				stream_id);
2241 		return -EINVAL;
2242 	}
2243 
2244 	ret = prepare_ring(xhci, ep_ring,
2245 			ep_ctx->ep_info & EP_STATE_MASK,
2246 			num_trbs, mem_flags);
2247 	if (ret)
2248 		return ret;
2249 
2250 	urb_priv = urb->hcpriv;
2251 	td = urb_priv->td[td_index];
2252 
2253 	INIT_LIST_HEAD(&td->td_list);
2254 	INIT_LIST_HEAD(&td->cancelled_td_list);
2255 
2256 	if (td_index == 0) {
2257 		ret = usb_hcd_link_urb_to_ep(xhci_to_hcd(xhci), urb);
2258 		if (unlikely(ret)) {
2259 			xhci_urb_free_priv(xhci, urb_priv);
2260 			urb->hcpriv = NULL;
2261 			return ret;
2262 		}
2263 	}
2264 
2265 	td->urb = urb;
2266 	/* Add this TD to the tail of the endpoint ring's TD list */
2267 	list_add_tail(&td->td_list, &ep_ring->td_list);
2268 	td->start_seg = ep_ring->enq_seg;
2269 	td->first_trb = ep_ring->enqueue;
2270 
2271 	urb_priv->td[td_index] = td;
2272 
2273 	return 0;
2274 }
2275 
2276 static unsigned int count_sg_trbs_needed(struct xhci_hcd *xhci, struct urb *urb)
2277 {
2278 	int num_sgs, num_trbs, running_total, temp, i;
2279 	struct scatterlist *sg;
2280 
2281 	sg = NULL;
2282 	num_sgs = urb->num_sgs;
2283 	temp = urb->transfer_buffer_length;
2284 
2285 	xhci_dbg(xhci, "count sg list trbs: \n");
2286 	num_trbs = 0;
2287 	for_each_sg(urb->sg, sg, num_sgs, i) {
2288 		unsigned int previous_total_trbs = num_trbs;
2289 		unsigned int len = sg_dma_len(sg);
2290 
2291 		/* Scatter gather list entries may cross 64KB boundaries */
2292 		running_total = TRB_MAX_BUFF_SIZE -
2293 			(sg_dma_address(sg) & ((1 << TRB_MAX_BUFF_SHIFT) - 1));
2294 		if (running_total != 0)
2295 			num_trbs++;
2296 
2297 		/* How many more 64KB chunks to transfer, how many more TRBs? */
2298 		while (running_total < sg_dma_len(sg)) {
2299 			num_trbs++;
2300 			running_total += TRB_MAX_BUFF_SIZE;
2301 		}
2302 		xhci_dbg(xhci, " sg #%d: dma = %#llx, len = %#x (%d), num_trbs = %d\n",
2303 				i, (unsigned long long)sg_dma_address(sg),
2304 				len, len, num_trbs - previous_total_trbs);
2305 
2306 		len = min_t(int, len, temp);
2307 		temp -= len;
2308 		if (temp == 0)
2309 			break;
2310 	}
2311 	xhci_dbg(xhci, "\n");
2312 	if (!in_interrupt())
2313 		dev_dbg(&urb->dev->dev, "ep %#x - urb len = %d, sglist used, num_trbs = %d\n",
2314 				urb->ep->desc.bEndpointAddress,
2315 				urb->transfer_buffer_length,
2316 				num_trbs);
2317 	return num_trbs;
2318 }
2319 
2320 static void check_trb_math(struct urb *urb, int num_trbs, int running_total)
2321 {
2322 	if (num_trbs != 0)
2323 		dev_dbg(&urb->dev->dev, "%s - ep %#x - Miscalculated number of "
2324 				"TRBs, %d left\n", __func__,
2325 				urb->ep->desc.bEndpointAddress, num_trbs);
2326 	if (running_total != urb->transfer_buffer_length)
2327 		dev_dbg(&urb->dev->dev, "%s - ep %#x - Miscalculated tx length, "
2328 				"queued %#x (%d), asked for %#x (%d)\n",
2329 				__func__,
2330 				urb->ep->desc.bEndpointAddress,
2331 				running_total, running_total,
2332 				urb->transfer_buffer_length,
2333 				urb->transfer_buffer_length);
2334 }
2335 
2336 static void giveback_first_trb(struct xhci_hcd *xhci, int slot_id,
2337 		unsigned int ep_index, unsigned int stream_id, int start_cycle,
2338 		struct xhci_generic_trb *start_trb, struct xhci_td *td)
2339 {
2340 	/*
2341 	 * Pass all the TRBs to the hardware at once and make sure this write
2342 	 * isn't reordered.
2343 	 */
2344 	wmb();
2345 	start_trb->field[3] |= start_cycle;
2346 	ring_ep_doorbell(xhci, slot_id, ep_index, stream_id);
2347 }
2348 
2349 /*
2350  * xHCI uses normal TRBs for both bulk and interrupt.  When the interrupt
2351  * endpoint is to be serviced, the xHC will consume (at most) one TD.  A TD
2352  * (comprised of sg list entries) can take several service intervals to
2353  * transmit.
2354  */
2355 int xhci_queue_intr_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
2356 		struct urb *urb, int slot_id, unsigned int ep_index)
2357 {
2358 	struct xhci_ep_ctx *ep_ctx = xhci_get_ep_ctx(xhci,
2359 			xhci->devs[slot_id]->out_ctx, ep_index);
2360 	int xhci_interval;
2361 	int ep_interval;
2362 
2363 	xhci_interval = EP_INTERVAL_TO_UFRAMES(ep_ctx->ep_info);
2364 	ep_interval = urb->interval;
2365 	/* Convert to microframes */
2366 	if (urb->dev->speed == USB_SPEED_LOW ||
2367 			urb->dev->speed == USB_SPEED_FULL)
2368 		ep_interval *= 8;
2369 	/* FIXME change this to a warning and a suggestion to use the new API
2370 	 * to set the polling interval (once the API is added).
2371 	 */
2372 	if (xhci_interval != ep_interval) {
2373 		if (!printk_ratelimit())
2374 			dev_dbg(&urb->dev->dev, "Driver uses different interval"
2375 					" (%d microframe%s) than xHCI "
2376 					"(%d microframe%s)\n",
2377 					ep_interval,
2378 					ep_interval == 1 ? "" : "s",
2379 					xhci_interval,
2380 					xhci_interval == 1 ? "" : "s");
2381 		urb->interval = xhci_interval;
2382 		/* Convert back to frames for LS/FS devices */
2383 		if (urb->dev->speed == USB_SPEED_LOW ||
2384 				urb->dev->speed == USB_SPEED_FULL)
2385 			urb->interval /= 8;
2386 	}
2387 	return xhci_queue_bulk_tx(xhci, GFP_ATOMIC, urb, slot_id, ep_index);
2388 }
2389 
2390 /*
2391  * The TD size is the number of bytes remaining in the TD (including this TRB),
2392  * right shifted by 10.
2393  * It must fit in bits 21:17, so it can't be bigger than 31.
2394  */
2395 static u32 xhci_td_remainder(unsigned int remainder)
2396 {
2397 	u32 max = (1 << (21 - 17 + 1)) - 1;
2398 
2399 	if ((remainder >> 10) >= max)
2400 		return max << 17;
2401 	else
2402 		return (remainder >> 10) << 17;
2403 }
2404 
2405 static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
2406 		struct urb *urb, int slot_id, unsigned int ep_index)
2407 {
2408 	struct xhci_ring *ep_ring;
2409 	unsigned int num_trbs;
2410 	struct urb_priv *urb_priv;
2411 	struct xhci_td *td;
2412 	struct scatterlist *sg;
2413 	int num_sgs;
2414 	int trb_buff_len, this_sg_len, running_total;
2415 	bool first_trb;
2416 	u64 addr;
2417 	bool more_trbs_coming;
2418 
2419 	struct xhci_generic_trb *start_trb;
2420 	int start_cycle;
2421 
2422 	ep_ring = xhci_urb_to_transfer_ring(xhci, urb);
2423 	if (!ep_ring)
2424 		return -EINVAL;
2425 
2426 	num_trbs = count_sg_trbs_needed(xhci, urb);
2427 	num_sgs = urb->num_sgs;
2428 
2429 	trb_buff_len = prepare_transfer(xhci, xhci->devs[slot_id],
2430 			ep_index, urb->stream_id,
2431 			num_trbs, urb, 0, mem_flags);
2432 	if (trb_buff_len < 0)
2433 		return trb_buff_len;
2434 
2435 	urb_priv = urb->hcpriv;
2436 	td = urb_priv->td[0];
2437 
2438 	/*
2439 	 * Don't give the first TRB to the hardware (by toggling the cycle bit)
2440 	 * until we've finished creating all the other TRBs.  The ring's cycle
2441 	 * state may change as we enqueue the other TRBs, so save it too.
2442 	 */
2443 	start_trb = &ep_ring->enqueue->generic;
2444 	start_cycle = ep_ring->cycle_state;
2445 
2446 	running_total = 0;
2447 	/*
2448 	 * How much data is in the first TRB?
2449 	 *
2450 	 * There are three forces at work for TRB buffer pointers and lengths:
2451 	 * 1. We don't want to walk off the end of this sg-list entry buffer.
2452 	 * 2. The transfer length that the driver requested may be smaller than
2453 	 *    the amount of memory allocated for this scatter-gather list.
2454 	 * 3. TRBs buffers can't cross 64KB boundaries.
2455 	 */
2456 	sg = urb->sg;
2457 	addr = (u64) sg_dma_address(sg);
2458 	this_sg_len = sg_dma_len(sg);
2459 	trb_buff_len = TRB_MAX_BUFF_SIZE -
2460 		(addr & ((1 << TRB_MAX_BUFF_SHIFT) - 1));
2461 	trb_buff_len = min_t(int, trb_buff_len, this_sg_len);
2462 	if (trb_buff_len > urb->transfer_buffer_length)
2463 		trb_buff_len = urb->transfer_buffer_length;
2464 	xhci_dbg(xhci, "First length to xfer from 1st sglist entry = %u\n",
2465 			trb_buff_len);
2466 
2467 	first_trb = true;
2468 	/* Queue the first TRB, even if it's zero-length */
2469 	do {
2470 		u32 field = 0;
2471 		u32 length_field = 0;
2472 		u32 remainder = 0;
2473 
2474 		/* Don't change the cycle bit of the first TRB until later */
2475 		if (first_trb)
2476 			first_trb = false;
2477 		else
2478 			field |= ep_ring->cycle_state;
2479 
2480 		/* Chain all the TRBs together; clear the chain bit in the last
2481 		 * TRB to indicate it's the last TRB in the chain.
2482 		 */
2483 		if (num_trbs > 1) {
2484 			field |= TRB_CHAIN;
2485 		} else {
2486 			/* FIXME - add check for ZERO_PACKET flag before this */
2487 			td->last_trb = ep_ring->enqueue;
2488 			field |= TRB_IOC;
2489 		}
2490 		xhci_dbg(xhci, " sg entry: dma = %#x, len = %#x (%d), "
2491 				"64KB boundary at %#x, end dma = %#x\n",
2492 				(unsigned int) addr, trb_buff_len, trb_buff_len,
2493 				(unsigned int) (addr + TRB_MAX_BUFF_SIZE) & ~(TRB_MAX_BUFF_SIZE - 1),
2494 				(unsigned int) addr + trb_buff_len);
2495 		if (TRB_MAX_BUFF_SIZE -
2496 				(addr & ((1 << TRB_MAX_BUFF_SHIFT) - 1)) < trb_buff_len) {
2497 			xhci_warn(xhci, "WARN: sg dma xfer crosses 64KB boundaries!\n");
2498 			xhci_dbg(xhci, "Next boundary at %#x, end dma = %#x\n",
2499 					(unsigned int) (addr + TRB_MAX_BUFF_SIZE) & ~(TRB_MAX_BUFF_SIZE - 1),
2500 					(unsigned int) addr + trb_buff_len);
2501 		}
2502 		remainder = xhci_td_remainder(urb->transfer_buffer_length -
2503 				running_total) ;
2504 		length_field = TRB_LEN(trb_buff_len) |
2505 			remainder |
2506 			TRB_INTR_TARGET(0);
2507 		if (num_trbs > 1)
2508 			more_trbs_coming = true;
2509 		else
2510 			more_trbs_coming = false;
2511 		queue_trb(xhci, ep_ring, false, more_trbs_coming,
2512 				lower_32_bits(addr),
2513 				upper_32_bits(addr),
2514 				length_field,
2515 				/* We always want to know if the TRB was short,
2516 				 * or we won't get an event when it completes.
2517 				 * (Unless we use event data TRBs, which are a
2518 				 * waste of space and HC resources.)
2519 				 */
2520 				field | TRB_ISP | TRB_TYPE(TRB_NORMAL));
2521 		--num_trbs;
2522 		running_total += trb_buff_len;
2523 
2524 		/* Calculate length for next transfer --
2525 		 * Are we done queueing all the TRBs for this sg entry?
2526 		 */
2527 		this_sg_len -= trb_buff_len;
2528 		if (this_sg_len == 0) {
2529 			--num_sgs;
2530 			if (num_sgs == 0)
2531 				break;
2532 			sg = sg_next(sg);
2533 			addr = (u64) sg_dma_address(sg);
2534 			this_sg_len = sg_dma_len(sg);
2535 		} else {
2536 			addr += trb_buff_len;
2537 		}
2538 
2539 		trb_buff_len = TRB_MAX_BUFF_SIZE -
2540 			(addr & ((1 << TRB_MAX_BUFF_SHIFT) - 1));
2541 		trb_buff_len = min_t(int, trb_buff_len, this_sg_len);
2542 		if (running_total + trb_buff_len > urb->transfer_buffer_length)
2543 			trb_buff_len =
2544 				urb->transfer_buffer_length - running_total;
2545 	} while (running_total < urb->transfer_buffer_length);
2546 
2547 	check_trb_math(urb, num_trbs, running_total);
2548 	giveback_first_trb(xhci, slot_id, ep_index, urb->stream_id,
2549 			start_cycle, start_trb, td);
2550 	return 0;
2551 }
2552 
2553 /* This is very similar to what ehci-q.c qtd_fill() does */
2554 int xhci_queue_bulk_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
2555 		struct urb *urb, int slot_id, unsigned int ep_index)
2556 {
2557 	struct xhci_ring *ep_ring;
2558 	struct urb_priv *urb_priv;
2559 	struct xhci_td *td;
2560 	int num_trbs;
2561 	struct xhci_generic_trb *start_trb;
2562 	bool first_trb;
2563 	bool more_trbs_coming;
2564 	int start_cycle;
2565 	u32 field, length_field;
2566 
2567 	int running_total, trb_buff_len, ret;
2568 	u64 addr;
2569 
2570 	if (urb->num_sgs)
2571 		return queue_bulk_sg_tx(xhci, mem_flags, urb, slot_id, ep_index);
2572 
2573 	ep_ring = xhci_urb_to_transfer_ring(xhci, urb);
2574 	if (!ep_ring)
2575 		return -EINVAL;
2576 
2577 	num_trbs = 0;
2578 	/* How much data is (potentially) left before the 64KB boundary? */
2579 	running_total = TRB_MAX_BUFF_SIZE -
2580 		(urb->transfer_dma & ((1 << TRB_MAX_BUFF_SHIFT) - 1));
2581 
2582 	/* If there's some data on this 64KB chunk, or we have to send a
2583 	 * zero-length transfer, we need at least one TRB
2584 	 */
2585 	if (running_total != 0 || urb->transfer_buffer_length == 0)
2586 		num_trbs++;
2587 	/* How many more 64KB chunks to transfer, how many more TRBs? */
2588 	while (running_total < urb->transfer_buffer_length) {
2589 		num_trbs++;
2590 		running_total += TRB_MAX_BUFF_SIZE;
2591 	}
2592 	/* FIXME: this doesn't deal with URB_ZERO_PACKET - need one more */
2593 
2594 	if (!in_interrupt())
2595 		dev_dbg(&urb->dev->dev, "ep %#x - urb len = %#x (%d), addr = %#llx, num_trbs = %d\n",
2596 				urb->ep->desc.bEndpointAddress,
2597 				urb->transfer_buffer_length,
2598 				urb->transfer_buffer_length,
2599 				(unsigned long long)urb->transfer_dma,
2600 				num_trbs);
2601 
2602 	ret = prepare_transfer(xhci, xhci->devs[slot_id],
2603 			ep_index, urb->stream_id,
2604 			num_trbs, urb, 0, mem_flags);
2605 	if (ret < 0)
2606 		return ret;
2607 
2608 	urb_priv = urb->hcpriv;
2609 	td = urb_priv->td[0];
2610 
2611 	/*
2612 	 * Don't give the first TRB to the hardware (by toggling the cycle bit)
2613 	 * until we've finished creating all the other TRBs.  The ring's cycle
2614 	 * state may change as we enqueue the other TRBs, so save it too.
2615 	 */
2616 	start_trb = &ep_ring->enqueue->generic;
2617 	start_cycle = ep_ring->cycle_state;
2618 
2619 	running_total = 0;
2620 	/* How much data is in the first TRB? */
2621 	addr = (u64) urb->transfer_dma;
2622 	trb_buff_len = TRB_MAX_BUFF_SIZE -
2623 		(urb->transfer_dma & ((1 << TRB_MAX_BUFF_SHIFT) - 1));
2624 	if (urb->transfer_buffer_length < trb_buff_len)
2625 		trb_buff_len = urb->transfer_buffer_length;
2626 
2627 	first_trb = true;
2628 
2629 	/* Queue the first TRB, even if it's zero-length */
2630 	do {
2631 		u32 remainder = 0;
2632 		field = 0;
2633 
2634 		/* Don't change the cycle bit of the first TRB until later */
2635 		if (first_trb)
2636 			first_trb = false;
2637 		else
2638 			field |= ep_ring->cycle_state;
2639 
2640 		/* Chain all the TRBs together; clear the chain bit in the last
2641 		 * TRB to indicate it's the last TRB in the chain.
2642 		 */
2643 		if (num_trbs > 1) {
2644 			field |= TRB_CHAIN;
2645 		} else {
2646 			/* FIXME - add check for ZERO_PACKET flag before this */
2647 			td->last_trb = ep_ring->enqueue;
2648 			field |= TRB_IOC;
2649 		}
2650 		remainder = xhci_td_remainder(urb->transfer_buffer_length -
2651 				running_total);
2652 		length_field = TRB_LEN(trb_buff_len) |
2653 			remainder |
2654 			TRB_INTR_TARGET(0);
2655 		if (num_trbs > 1)
2656 			more_trbs_coming = true;
2657 		else
2658 			more_trbs_coming = false;
2659 		queue_trb(xhci, ep_ring, false, more_trbs_coming,
2660 				lower_32_bits(addr),
2661 				upper_32_bits(addr),
2662 				length_field,
2663 				/* We always want to know if the TRB was short,
2664 				 * or we won't get an event when it completes.
2665 				 * (Unless we use event data TRBs, which are a
2666 				 * waste of space and HC resources.)
2667 				 */
2668 				field | TRB_ISP | TRB_TYPE(TRB_NORMAL));
2669 		--num_trbs;
2670 		running_total += trb_buff_len;
2671 
2672 		/* Calculate length for next transfer */
2673 		addr += trb_buff_len;
2674 		trb_buff_len = urb->transfer_buffer_length - running_total;
2675 		if (trb_buff_len > TRB_MAX_BUFF_SIZE)
2676 			trb_buff_len = TRB_MAX_BUFF_SIZE;
2677 	} while (running_total < urb->transfer_buffer_length);
2678 
2679 	check_trb_math(urb, num_trbs, running_total);
2680 	giveback_first_trb(xhci, slot_id, ep_index, urb->stream_id,
2681 			start_cycle, start_trb, td);
2682 	return 0;
2683 }
2684 
2685 /* Caller must have locked xhci->lock */
2686 int xhci_queue_ctrl_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
2687 		struct urb *urb, int slot_id, unsigned int ep_index)
2688 {
2689 	struct xhci_ring *ep_ring;
2690 	int num_trbs;
2691 	int ret;
2692 	struct usb_ctrlrequest *setup;
2693 	struct xhci_generic_trb *start_trb;
2694 	int start_cycle;
2695 	u32 field, length_field;
2696 	struct urb_priv *urb_priv;
2697 	struct xhci_td *td;
2698 
2699 	ep_ring = xhci_urb_to_transfer_ring(xhci, urb);
2700 	if (!ep_ring)
2701 		return -EINVAL;
2702 
2703 	/*
2704 	 * Need to copy setup packet into setup TRB, so we can't use the setup
2705 	 * DMA address.
2706 	 */
2707 	if (!urb->setup_packet)
2708 		return -EINVAL;
2709 
2710 	if (!in_interrupt())
2711 		xhci_dbg(xhci, "Queueing ctrl tx for slot id %d, ep %d\n",
2712 				slot_id, ep_index);
2713 	/* 1 TRB for setup, 1 for status */
2714 	num_trbs = 2;
2715 	/*
2716 	 * Don't need to check if we need additional event data and normal TRBs,
2717 	 * since data in control transfers will never get bigger than 16MB
2718 	 * XXX: can we get a buffer that crosses 64KB boundaries?
2719 	 */
2720 	if (urb->transfer_buffer_length > 0)
2721 		num_trbs++;
2722 	ret = prepare_transfer(xhci, xhci->devs[slot_id],
2723 			ep_index, urb->stream_id,
2724 			num_trbs, urb, 0, mem_flags);
2725 	if (ret < 0)
2726 		return ret;
2727 
2728 	urb_priv = urb->hcpriv;
2729 	td = urb_priv->td[0];
2730 
2731 	/*
2732 	 * Don't give the first TRB to the hardware (by toggling the cycle bit)
2733 	 * until we've finished creating all the other TRBs.  The ring's cycle
2734 	 * state may change as we enqueue the other TRBs, so save it too.
2735 	 */
2736 	start_trb = &ep_ring->enqueue->generic;
2737 	start_cycle = ep_ring->cycle_state;
2738 
2739 	/* Queue setup TRB - see section 6.4.1.2.1 */
2740 	/* FIXME better way to translate setup_packet into two u32 fields? */
2741 	setup = (struct usb_ctrlrequest *) urb->setup_packet;
2742 	queue_trb(xhci, ep_ring, false, true,
2743 			/* FIXME endianness is probably going to bite my ass here. */
2744 			setup->bRequestType | setup->bRequest << 8 | setup->wValue << 16,
2745 			setup->wIndex | setup->wLength << 16,
2746 			TRB_LEN(8) | TRB_INTR_TARGET(0),
2747 			/* Immediate data in pointer */
2748 			TRB_IDT | TRB_TYPE(TRB_SETUP));
2749 
2750 	/* If there's data, queue data TRBs */
2751 	field = 0;
2752 	length_field = TRB_LEN(urb->transfer_buffer_length) |
2753 		xhci_td_remainder(urb->transfer_buffer_length) |
2754 		TRB_INTR_TARGET(0);
2755 	if (urb->transfer_buffer_length > 0) {
2756 		if (setup->bRequestType & USB_DIR_IN)
2757 			field |= TRB_DIR_IN;
2758 		queue_trb(xhci, ep_ring, false, true,
2759 				lower_32_bits(urb->transfer_dma),
2760 				upper_32_bits(urb->transfer_dma),
2761 				length_field,
2762 				/* Event on short tx */
2763 				field | TRB_ISP | TRB_TYPE(TRB_DATA) | ep_ring->cycle_state);
2764 	}
2765 
2766 	/* Save the DMA address of the last TRB in the TD */
2767 	td->last_trb = ep_ring->enqueue;
2768 
2769 	/* Queue status TRB - see Table 7 and sections 4.11.2.2 and 6.4.1.2.3 */
2770 	/* If the device sent data, the status stage is an OUT transfer */
2771 	if (urb->transfer_buffer_length > 0 && setup->bRequestType & USB_DIR_IN)
2772 		field = 0;
2773 	else
2774 		field = TRB_DIR_IN;
2775 	queue_trb(xhci, ep_ring, false, false,
2776 			0,
2777 			0,
2778 			TRB_INTR_TARGET(0),
2779 			/* Event on completion */
2780 			field | TRB_IOC | TRB_TYPE(TRB_STATUS) | ep_ring->cycle_state);
2781 
2782 	giveback_first_trb(xhci, slot_id, ep_index, 0,
2783 			start_cycle, start_trb, td);
2784 	return 0;
2785 }
2786 
2787 static int count_isoc_trbs_needed(struct xhci_hcd *xhci,
2788 		struct urb *urb, int i)
2789 {
2790 	int num_trbs = 0;
2791 	u64 addr, td_len, running_total;
2792 
2793 	addr = (u64) (urb->transfer_dma + urb->iso_frame_desc[i].offset);
2794 	td_len = urb->iso_frame_desc[i].length;
2795 
2796 	running_total = TRB_MAX_BUFF_SIZE -
2797 			(addr & ((1 << TRB_MAX_BUFF_SHIFT) - 1));
2798 	if (running_total != 0)
2799 		num_trbs++;
2800 
2801 	while (running_total < td_len) {
2802 		num_trbs++;
2803 		running_total += TRB_MAX_BUFF_SIZE;
2804 	}
2805 
2806 	return num_trbs;
2807 }
2808 
2809 /* This is for isoc transfer */
2810 static int xhci_queue_isoc_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
2811 		struct urb *urb, int slot_id, unsigned int ep_index)
2812 {
2813 	struct xhci_ring *ep_ring;
2814 	struct urb_priv *urb_priv;
2815 	struct xhci_td *td;
2816 	int num_tds, trbs_per_td;
2817 	struct xhci_generic_trb *start_trb;
2818 	bool first_trb;
2819 	int start_cycle;
2820 	u32 field, length_field;
2821 	int running_total, trb_buff_len, td_len, td_remain_len, ret;
2822 	u64 start_addr, addr;
2823 	int i, j;
2824 
2825 	ep_ring = xhci->devs[slot_id]->eps[ep_index].ring;
2826 
2827 	num_tds = urb->number_of_packets;
2828 	if (num_tds < 1) {
2829 		xhci_dbg(xhci, "Isoc URB with zero packets?\n");
2830 		return -EINVAL;
2831 	}
2832 
2833 	if (!in_interrupt())
2834 		dev_dbg(&urb->dev->dev, "ep %#x - urb len = %#x (%d),"
2835 				" addr = %#llx, num_tds = %d\n",
2836 				urb->ep->desc.bEndpointAddress,
2837 				urb->transfer_buffer_length,
2838 				urb->transfer_buffer_length,
2839 				(unsigned long long)urb->transfer_dma,
2840 				num_tds);
2841 
2842 	start_addr = (u64) urb->transfer_dma;
2843 	start_trb = &ep_ring->enqueue->generic;
2844 	start_cycle = ep_ring->cycle_state;
2845 
2846 	/* Queue the first TRB, even if it's zero-length */
2847 	for (i = 0; i < num_tds; i++) {
2848 		first_trb = true;
2849 
2850 		running_total = 0;
2851 		addr = start_addr + urb->iso_frame_desc[i].offset;
2852 		td_len = urb->iso_frame_desc[i].length;
2853 		td_remain_len = td_len;
2854 
2855 		trbs_per_td = count_isoc_trbs_needed(xhci, urb, i);
2856 
2857 		ret = prepare_transfer(xhci, xhci->devs[slot_id], ep_index,
2858 				urb->stream_id, trbs_per_td, urb, i, mem_flags);
2859 		if (ret < 0)
2860 			return ret;
2861 
2862 		urb_priv = urb->hcpriv;
2863 		td = urb_priv->td[i];
2864 
2865 		for (j = 0; j < trbs_per_td; j++) {
2866 			u32 remainder = 0;
2867 			field = 0;
2868 
2869 			if (first_trb) {
2870 				/* Queue the isoc TRB */
2871 				field |= TRB_TYPE(TRB_ISOC);
2872 				/* Assume URB_ISO_ASAP is set */
2873 				field |= TRB_SIA;
2874 				if (i > 0)
2875 					field |= ep_ring->cycle_state;
2876 				first_trb = false;
2877 			} else {
2878 				/* Queue other normal TRBs */
2879 				field |= TRB_TYPE(TRB_NORMAL);
2880 				field |= ep_ring->cycle_state;
2881 			}
2882 
2883 			/* Chain all the TRBs together; clear the chain bit in
2884 			 * the last TRB to indicate it's the last TRB in the
2885 			 * chain.
2886 			 */
2887 			if (j < trbs_per_td - 1) {
2888 				field |= TRB_CHAIN;
2889 			} else {
2890 				td->last_trb = ep_ring->enqueue;
2891 				field |= TRB_IOC;
2892 			}
2893 
2894 			/* Calculate TRB length */
2895 			trb_buff_len = TRB_MAX_BUFF_SIZE -
2896 				(addr & ((1 << TRB_MAX_BUFF_SHIFT) - 1));
2897 			if (trb_buff_len > td_remain_len)
2898 				trb_buff_len = td_remain_len;
2899 
2900 			remainder = xhci_td_remainder(td_len - running_total);
2901 			length_field = TRB_LEN(trb_buff_len) |
2902 				remainder |
2903 				TRB_INTR_TARGET(0);
2904 			queue_trb(xhci, ep_ring, false, false,
2905 				lower_32_bits(addr),
2906 				upper_32_bits(addr),
2907 				length_field,
2908 				/* We always want to know if the TRB was short,
2909 				 * or we won't get an event when it completes.
2910 				 * (Unless we use event data TRBs, which are a
2911 				 * waste of space and HC resources.)
2912 				 */
2913 				field | TRB_ISP);
2914 			running_total += trb_buff_len;
2915 
2916 			addr += trb_buff_len;
2917 			td_remain_len -= trb_buff_len;
2918 		}
2919 
2920 		/* Check TD length */
2921 		if (running_total != td_len) {
2922 			xhci_err(xhci, "ISOC TD length unmatch\n");
2923 			return -EINVAL;
2924 		}
2925 	}
2926 
2927 	wmb();
2928 	start_trb->field[3] |= start_cycle;
2929 
2930 	ring_ep_doorbell(xhci, slot_id, ep_index, urb->stream_id);
2931 	return 0;
2932 }
2933 
2934 /*
2935  * Check transfer ring to guarantee there is enough room for the urb.
2936  * Update ISO URB start_frame and interval.
2937  * Update interval as xhci_queue_intr_tx does. Just use xhci frame_index to
2938  * update the urb->start_frame by now.
2939  * Always assume URB_ISO_ASAP set, and NEVER use urb->start_frame as input.
2940  */
2941 int xhci_queue_isoc_tx_prepare(struct xhci_hcd *xhci, gfp_t mem_flags,
2942 		struct urb *urb, int slot_id, unsigned int ep_index)
2943 {
2944 	struct xhci_virt_device *xdev;
2945 	struct xhci_ring *ep_ring;
2946 	struct xhci_ep_ctx *ep_ctx;
2947 	int start_frame;
2948 	int xhci_interval;
2949 	int ep_interval;
2950 	int num_tds, num_trbs, i;
2951 	int ret;
2952 
2953 	xdev = xhci->devs[slot_id];
2954 	ep_ring = xdev->eps[ep_index].ring;
2955 	ep_ctx = xhci_get_ep_ctx(xhci, xdev->out_ctx, ep_index);
2956 
2957 	num_trbs = 0;
2958 	num_tds = urb->number_of_packets;
2959 	for (i = 0; i < num_tds; i++)
2960 		num_trbs += count_isoc_trbs_needed(xhci, urb, i);
2961 
2962 	/* Check the ring to guarantee there is enough room for the whole urb.
2963 	 * Do not insert any td of the urb to the ring if the check failed.
2964 	 */
2965 	ret = prepare_ring(xhci, ep_ring, ep_ctx->ep_info & EP_STATE_MASK,
2966 				num_trbs, mem_flags);
2967 	if (ret)
2968 		return ret;
2969 
2970 	start_frame = xhci_readl(xhci, &xhci->run_regs->microframe_index);
2971 	start_frame &= 0x3fff;
2972 
2973 	urb->start_frame = start_frame;
2974 	if (urb->dev->speed == USB_SPEED_LOW ||
2975 			urb->dev->speed == USB_SPEED_FULL)
2976 		urb->start_frame >>= 3;
2977 
2978 	xhci_interval = EP_INTERVAL_TO_UFRAMES(ep_ctx->ep_info);
2979 	ep_interval = urb->interval;
2980 	/* Convert to microframes */
2981 	if (urb->dev->speed == USB_SPEED_LOW ||
2982 			urb->dev->speed == USB_SPEED_FULL)
2983 		ep_interval *= 8;
2984 	/* FIXME change this to a warning and a suggestion to use the new API
2985 	 * to set the polling interval (once the API is added).
2986 	 */
2987 	if (xhci_interval != ep_interval) {
2988 		if (!printk_ratelimit())
2989 			dev_dbg(&urb->dev->dev, "Driver uses different interval"
2990 					" (%d microframe%s) than xHCI "
2991 					"(%d microframe%s)\n",
2992 					ep_interval,
2993 					ep_interval == 1 ? "" : "s",
2994 					xhci_interval,
2995 					xhci_interval == 1 ? "" : "s");
2996 		urb->interval = xhci_interval;
2997 		/* Convert back to frames for LS/FS devices */
2998 		if (urb->dev->speed == USB_SPEED_LOW ||
2999 				urb->dev->speed == USB_SPEED_FULL)
3000 			urb->interval /= 8;
3001 	}
3002 	return xhci_queue_isoc_tx(xhci, GFP_ATOMIC, urb, slot_id, ep_index);
3003 }
3004 
3005 /****		Command Ring Operations		****/
3006 
3007 /* Generic function for queueing a command TRB on the command ring.
3008  * Check to make sure there's room on the command ring for one command TRB.
3009  * Also check that there's room reserved for commands that must not fail.
3010  * If this is a command that must not fail, meaning command_must_succeed = TRUE,
3011  * then only check for the number of reserved spots.
3012  * Don't decrement xhci->cmd_ring_reserved_trbs after we've queued the TRB
3013  * because the command event handler may want to resubmit a failed command.
3014  */
3015 static int queue_command(struct xhci_hcd *xhci, u32 field1, u32 field2,
3016 		u32 field3, u32 field4, bool command_must_succeed)
3017 {
3018 	int reserved_trbs = xhci->cmd_ring_reserved_trbs;
3019 	int ret;
3020 
3021 	if (!command_must_succeed)
3022 		reserved_trbs++;
3023 
3024 	ret = prepare_ring(xhci, xhci->cmd_ring, EP_STATE_RUNNING,
3025 			reserved_trbs, GFP_ATOMIC);
3026 	if (ret < 0) {
3027 		xhci_err(xhci, "ERR: No room for command on command ring\n");
3028 		if (command_must_succeed)
3029 			xhci_err(xhci, "ERR: Reserved TRB counting for "
3030 					"unfailable commands failed.\n");
3031 		return ret;
3032 	}
3033 	queue_trb(xhci, xhci->cmd_ring, false, false, field1, field2, field3,
3034 			field4 | xhci->cmd_ring->cycle_state);
3035 	return 0;
3036 }
3037 
3038 /* Queue a no-op command on the command ring */
3039 static int queue_cmd_noop(struct xhci_hcd *xhci)
3040 {
3041 	return queue_command(xhci, 0, 0, 0, TRB_TYPE(TRB_CMD_NOOP), false);
3042 }
3043 
3044 /*
3045  * Place a no-op command on the command ring to test the command and
3046  * event ring.
3047  */
3048 void *xhci_setup_one_noop(struct xhci_hcd *xhci)
3049 {
3050 	if (queue_cmd_noop(xhci) < 0)
3051 		return NULL;
3052 	xhci->noops_submitted++;
3053 	return xhci_ring_cmd_db;
3054 }
3055 
3056 /* Queue a slot enable or disable request on the command ring */
3057 int xhci_queue_slot_control(struct xhci_hcd *xhci, u32 trb_type, u32 slot_id)
3058 {
3059 	return queue_command(xhci, 0, 0, 0,
3060 			TRB_TYPE(trb_type) | SLOT_ID_FOR_TRB(slot_id), false);
3061 }
3062 
3063 /* Queue an address device command TRB */
3064 int xhci_queue_address_device(struct xhci_hcd *xhci, dma_addr_t in_ctx_ptr,
3065 		u32 slot_id)
3066 {
3067 	return queue_command(xhci, lower_32_bits(in_ctx_ptr),
3068 			upper_32_bits(in_ctx_ptr), 0,
3069 			TRB_TYPE(TRB_ADDR_DEV) | SLOT_ID_FOR_TRB(slot_id),
3070 			false);
3071 }
3072 
3073 int xhci_queue_vendor_command(struct xhci_hcd *xhci,
3074 		u32 field1, u32 field2, u32 field3, u32 field4)
3075 {
3076 	return queue_command(xhci, field1, field2, field3, field4, false);
3077 }
3078 
3079 /* Queue a reset device command TRB */
3080 int xhci_queue_reset_device(struct xhci_hcd *xhci, u32 slot_id)
3081 {
3082 	return queue_command(xhci, 0, 0, 0,
3083 			TRB_TYPE(TRB_RESET_DEV) | SLOT_ID_FOR_TRB(slot_id),
3084 			false);
3085 }
3086 
3087 /* Queue a configure endpoint command TRB */
3088 int xhci_queue_configure_endpoint(struct xhci_hcd *xhci, dma_addr_t in_ctx_ptr,
3089 		u32 slot_id, bool command_must_succeed)
3090 {
3091 	return queue_command(xhci, lower_32_bits(in_ctx_ptr),
3092 			upper_32_bits(in_ctx_ptr), 0,
3093 			TRB_TYPE(TRB_CONFIG_EP) | SLOT_ID_FOR_TRB(slot_id),
3094 			command_must_succeed);
3095 }
3096 
3097 /* Queue an evaluate context command TRB */
3098 int xhci_queue_evaluate_context(struct xhci_hcd *xhci, dma_addr_t in_ctx_ptr,
3099 		u32 slot_id)
3100 {
3101 	return queue_command(xhci, lower_32_bits(in_ctx_ptr),
3102 			upper_32_bits(in_ctx_ptr), 0,
3103 			TRB_TYPE(TRB_EVAL_CONTEXT) | SLOT_ID_FOR_TRB(slot_id),
3104 			false);
3105 }
3106 
3107 int xhci_queue_stop_endpoint(struct xhci_hcd *xhci, int slot_id,
3108 		unsigned int ep_index)
3109 {
3110 	u32 trb_slot_id = SLOT_ID_FOR_TRB(slot_id);
3111 	u32 trb_ep_index = EP_ID_FOR_TRB(ep_index);
3112 	u32 type = TRB_TYPE(TRB_STOP_RING);
3113 
3114 	return queue_command(xhci, 0, 0, 0,
3115 			trb_slot_id | trb_ep_index | type, false);
3116 }
3117 
3118 /* Set Transfer Ring Dequeue Pointer command.
3119  * This should not be used for endpoints that have streams enabled.
3120  */
3121 static int queue_set_tr_deq(struct xhci_hcd *xhci, int slot_id,
3122 		unsigned int ep_index, unsigned int stream_id,
3123 		struct xhci_segment *deq_seg,
3124 		union xhci_trb *deq_ptr, u32 cycle_state)
3125 {
3126 	dma_addr_t addr;
3127 	u32 trb_slot_id = SLOT_ID_FOR_TRB(slot_id);
3128 	u32 trb_ep_index = EP_ID_FOR_TRB(ep_index);
3129 	u32 trb_stream_id = STREAM_ID_FOR_TRB(stream_id);
3130 	u32 type = TRB_TYPE(TRB_SET_DEQ);
3131 
3132 	addr = xhci_trb_virt_to_dma(deq_seg, deq_ptr);
3133 	if (addr == 0) {
3134 		xhci_warn(xhci, "WARN Cannot submit Set TR Deq Ptr\n");
3135 		xhci_warn(xhci, "WARN deq seg = %p, deq pt = %p\n",
3136 				deq_seg, deq_ptr);
3137 		return 0;
3138 	}
3139 	return queue_command(xhci, lower_32_bits(addr) | cycle_state,
3140 			upper_32_bits(addr), trb_stream_id,
3141 			trb_slot_id | trb_ep_index | type, false);
3142 }
3143 
3144 int xhci_queue_reset_ep(struct xhci_hcd *xhci, int slot_id,
3145 		unsigned int ep_index)
3146 {
3147 	u32 trb_slot_id = SLOT_ID_FOR_TRB(slot_id);
3148 	u32 trb_ep_index = EP_ID_FOR_TRB(ep_index);
3149 	u32 type = TRB_TYPE(TRB_RESET_EP);
3150 
3151 	return queue_command(xhci, 0, 0, 0, trb_slot_id | trb_ep_index | type,
3152 			false);
3153 }
3154