1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * Copyright (C) 2001-2004 by David Brownell
   4 */
   5
   6/* this file is part of ehci-hcd.c */
   7
   8/*-------------------------------------------------------------------------*/
   9
  10/*
  11 * EHCI hardware queue manipulation ... the core.  QH/QTD manipulation.
  12 *
  13 * Control, bulk, and interrupt traffic all use "qh" lists.  They list "qtd"
  14 * entries describing USB transactions, max 16-20kB/entry (with 4kB-aligned
  15 * buffers needed for the larger number).  We use one QH per endpoint, queue
  16 * multiple urbs (all three types) per endpoint.  URBs may need several qtds.
  17 *
  18 * ISO traffic uses "ISO TD" (itd, and sitd) records, and (along with
  19 * interrupts) needs careful scheduling.  Performance improvements can be
  20 * an ongoing challenge.  That's in "ehci-sched.c".
  21 *
  22 * USB 1.1 devices are handled (a) by "companion" OHCI or UHCI root hubs,
  23 * or otherwise through transaction translators (TTs) in USB 2.0 hubs using
  24 * (b) special fields in qh entries or (c) split iso entries.  TTs will
  25 * buffer low/full speed data so the host collects it at high speed.
  26 */
  27
  28/*-------------------------------------------------------------------------*/
  29
  30/* PID Codes that are used here, from EHCI specification, Table 3-16. */
  31#define PID_CODE_IN    1
  32#define PID_CODE_SETUP 2
  33
  34/* fill a qtd, returning how much of the buffer we were able to queue up */
  35
  36static unsigned int
  37qtd_fill(struct ehci_hcd *ehci, struct ehci_qtd *qtd, dma_addr_t buf,
  38		  size_t len, int token, int maxpacket)
  39{
  40	unsigned int count;
  41	u64	addr = buf;
  42	int	i;
  43
  44	/* one buffer entry per 4K ... first might be short or unaligned */
  45	qtd->hw_buf[0] = cpu_to_hc32(ehci, (u32)addr);
  46	qtd->hw_buf_hi[0] = cpu_to_hc32(ehci, (u32)(addr >> 32));
  47	count = 0x1000 - (buf & 0x0fff);	/* rest of that page */
  48	if (likely (len < count))		/* ... iff needed */
  49		count = len;
  50	else {
  51		buf +=  0x1000;
  52		buf &= ~0x0fff;
  53
  54		/* per-qtd limit: from 16K to 20K (best alignment) */
  55		for (i = 1; count < len && i < 5; i++) {
  56			addr = buf;
  57			qtd->hw_buf[i] = cpu_to_hc32(ehci, (u32)addr);
  58			qtd->hw_buf_hi[i] = cpu_to_hc32(ehci,
  59					(u32)(addr >> 32));
  60			buf += 0x1000;
  61			if ((count + 0x1000) < len)
  62				count += 0x1000;
  63			else
  64				count = len;
  65		}
  66
  67		/* short packets may only terminate transfers */
  68		if (count != len)
  69			count -= (count % maxpacket);
  70	}
  71	qtd->hw_token = cpu_to_hc32(ehci, (count << 16) | token);
  72	qtd->length = count;
  73
  74	return count;
  75}
  76
  77/*-------------------------------------------------------------------------*/
  78
  79static inline void
  80qh_update (struct ehci_hcd *ehci, struct ehci_qh *qh, struct ehci_qtd *qtd)
  81{
  82	struct ehci_qh_hw *hw = qh->hw;
  83
  84	/* writes to an active overlay are unsafe */
  85	WARN_ON(qh->qh_state != QH_STATE_IDLE);
  86
  87	hw->hw_qtd_next = QTD_NEXT(ehci, qtd->qtd_dma);
  88	hw->hw_alt_next = EHCI_LIST_END(ehci);
  89
  90	/* Except for control endpoints, we make hardware maintain data
  91	 * toggle (like OHCI) ... here (re)initialize the toggle in the QH,
  92	 * and set the pseudo-toggle in udev. Only usb_clear_halt() will
  93	 * ever clear it.
  94	 */
  95	if (!(hw->hw_info1 & cpu_to_hc32(ehci, QH_TOGGLE_CTL))) {
  96		unsigned	is_out, epnum;
  97
  98		is_out = qh->is_out;
  99		epnum = (hc32_to_cpup(ehci, &hw->hw_info1) >> 8) & 0x0f;
 100		if (unlikely(!usb_gettoggle(qh->ps.udev, epnum, is_out))) {
 101			hw->hw_token &= ~cpu_to_hc32(ehci, QTD_TOGGLE);
 102			usb_settoggle(qh->ps.udev, epnum, is_out, 1);
 103		}
 104	}
 105
 106	hw->hw_token &= cpu_to_hc32(ehci, QTD_TOGGLE | QTD_STS_PING);
 107}
 108
 109/* if it weren't for a common silicon quirk (writing the dummy into the qh
 110 * overlay, so qh->hw_token wrongly becomes inactive/halted), only fault
 111 * recovery (including urb dequeue) would need software changes to a QH...
 112 */
 113static void
 114qh_refresh (struct ehci_hcd *ehci, struct ehci_qh *qh)
 115{
 116	struct ehci_qtd *qtd;
 117
 118	qtd = list_entry(qh->qtd_list.next, struct ehci_qtd, qtd_list);
 119
 120	/*
 121	 * first qtd may already be partially processed.
 122	 * If we come here during unlink, the QH overlay region
 123	 * might have reference to the just unlinked qtd. The
 124	 * qtd is updated in qh_completions(). Update the QH
 125	 * overlay here.
 126	 */
 127	if (qh->hw->hw_token & ACTIVE_BIT(ehci)) {
 128		qh->hw->hw_qtd_next = qtd->hw_next;
 129		if (qh->should_be_inactive)
 130			ehci_warn(ehci, "qh %p should be inactive!\n", qh);
 131	} else {
 132		qh_update(ehci, qh, qtd);
 133	}
 134	qh->should_be_inactive = 0;
 135}
 136
 137/*-------------------------------------------------------------------------*/
 138
 139static void qh_link_async(struct ehci_hcd *ehci, struct ehci_qh *qh);
 140
 141static void ehci_clear_tt_buffer_complete(struct usb_hcd *hcd,
 142		struct usb_host_endpoint *ep)
 143{
 144	struct ehci_hcd		*ehci = hcd_to_ehci(hcd);
 145	struct ehci_qh		*qh = ep->hcpriv;
 146	unsigned long		flags;
 147
 148	spin_lock_irqsave(&ehci->lock, flags);
 149	qh->clearing_tt = 0;
 150	if (qh->qh_state == QH_STATE_IDLE && !list_empty(&qh->qtd_list)
 151			&& ehci->rh_state == EHCI_RH_RUNNING)
 152		qh_link_async(ehci, qh);
 153	spin_unlock_irqrestore(&ehci->lock, flags);
 154}
 155
 156static void ehci_clear_tt_buffer(struct ehci_hcd *ehci, struct ehci_qh *qh,
 157		struct urb *urb, u32 token)
 158{
 159
 160	/* If an async split transaction gets an error or is unlinked,
 161	 * the TT buffer may be left in an indeterminate state.  We
 162	 * have to clear the TT buffer.
 163	 *
 164	 * Note: this routine is never called for Isochronous transfers.
 165	 */
 166	if (urb->dev->tt && !usb_pipeint(urb->pipe) && !qh->clearing_tt) {
 167#ifdef CONFIG_DYNAMIC_DEBUG
 168		struct usb_device *tt = urb->dev->tt->hub;
 169		dev_dbg(&tt->dev,
 170			"clear tt buffer port %d, a%d ep%d t%08x\n",
 171			urb->dev->ttport, urb->dev->devnum,
 172			usb_pipeendpoint(urb->pipe), token);
 173#endif /* CONFIG_DYNAMIC_DEBUG */
 174		if (!ehci_is_TDI(ehci)
 175				|| urb->dev->tt->hub !=
 176				   ehci_to_hcd(ehci)->self.root_hub) {
 177			if (usb_hub_clear_tt_buffer(urb) == 0)
 178				qh->clearing_tt = 1;
 179		} else {
 180
 181			/* REVISIT ARC-derived cores don't clear the root
 182			 * hub TT buffer in this way...
 183			 */
 184		}
 185	}
 186}
 187
 188static int qtd_copy_status (
 189	struct ehci_hcd *ehci,
 190	struct urb *urb,
 191	size_t length,
 192	u32 token
 193)
 194{
 195	int	status = -EINPROGRESS;
 196
 197	/* count IN/OUT bytes, not SETUP (even short packets) */
 198	if (likely(QTD_PID(token) != PID_CODE_SETUP))
 199		urb->actual_length += length - QTD_LENGTH (token);
 200
 201	/* don't modify error codes */
 202	if (unlikely(urb->unlinked))
 203		return status;
 204
 205	/* force cleanup after short read; not always an error */
 206	if (unlikely (IS_SHORT_READ (token)))
 207		status = -EREMOTEIO;
 208
 209	/* serious "can't proceed" faults reported by the hardware */
 210	if (token & QTD_STS_HALT) {
 211		if (token & QTD_STS_BABBLE) {
 212			/* FIXME "must" disable babbling device's port too */
 213			status = -EOVERFLOW;
 214		/*
 215		 * When MMF is active and PID Code is IN, queue is halted.
 216		 * EHCI Specification, Table 4-13.
 217		 */
 218		} else if ((token & QTD_STS_MMF) &&
 219					(QTD_PID(token) == PID_CODE_IN)) {
 220			status = -EPROTO;
 221		/* CERR nonzero + halt --> stall */
 222		} else if (QTD_CERR(token)) {
 223			status = -EPIPE;
 224
 225		/* In theory, more than one of the following bits can be set
 226		 * since they are sticky and the transaction is retried.
 227		 * Which to test first is rather arbitrary.
 228		 */
 229		} else if (token & QTD_STS_MMF) {
 230			/* fs/ls interrupt xfer missed the complete-split */
 231			status = -EPROTO;
 232		} else if (token & QTD_STS_DBE) {
 233			status = (QTD_PID (token) == 1) /* IN ? */
 234				? -ENOSR  /* hc couldn't read data */
 235				: -ECOMM; /* hc couldn't write data */
 236		} else if (token & QTD_STS_XACT) {
 237			/* timeout, bad CRC, wrong PID, etc */
 238			ehci_dbg(ehci, "devpath %s ep%d%s 3strikes\n",
 239				urb->dev->devpath,
 240				usb_pipeendpoint(urb->pipe),
 241				usb_pipein(urb->pipe) ? "in" : "out");
 242			status = -EPROTO;
 243		} else {	/* unknown */
 244			status = -EPROTO;
 245		}
 246	}
 247
 248	return status;
 249}
 250
 251static void
 252ehci_urb_done(struct ehci_hcd *ehci, struct urb *urb, int status)
 253{
 254	if (usb_pipetype(urb->pipe) == PIPE_INTERRUPT) {
 255		/* ... update hc-wide periodic stats */
 256		ehci_to_hcd(ehci)->self.bandwidth_int_reqs--;
 257	}
 258
 259	if (unlikely(urb->unlinked)) {
 260		INCR(ehci->stats.unlink);
 261	} else {
 262		/* report non-error and short read status as zero */
 263		if (status == -EINPROGRESS || status == -EREMOTEIO)
 264			status = 0;
 265		INCR(ehci->stats.complete);
 266	}
 267
 268#ifdef EHCI_URB_TRACE
 269	ehci_dbg (ehci,
 270		"%s %s urb %p ep%d%s status %d len %d/%d\n",
 271		__func__, urb->dev->devpath, urb,
 272		usb_pipeendpoint (urb->pipe),
 273		usb_pipein (urb->pipe) ? "in" : "out",
 274		status,
 275		urb->actual_length, urb->transfer_buffer_length);
 276#endif
 277
 278	usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
 279	usb_hcd_giveback_urb(ehci_to_hcd(ehci), urb, status);
 280}
 281
 282static int qh_schedule (struct ehci_hcd *ehci, struct ehci_qh *qh);
 283
 284/*
 285 * Process and free completed qtds for a qh, returning URBs to drivers.
 286 * Chases up to qh->hw_current.  Returns nonzero if the caller should
 287 * unlink qh.
 288 */
 289static unsigned
 290qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh)
 291{
 292	struct ehci_qtd		*last, *end = qh->dummy;
 293	struct list_head	*entry, *tmp;
 294	int			last_status;
 295	int			stopped;
 296	u8			state;
 297	struct ehci_qh_hw	*hw = qh->hw;
 298
 299	/* completions (or tasks on other cpus) must never clobber HALT
 300	 * till we've gone through and cleaned everything up, even when
 301	 * they add urbs to this qh's queue or mark them for unlinking.
 302	 *
 303	 * NOTE:  unlinking expects to be done in queue order.
 304	 *
 305	 * It's a bug for qh->qh_state to be anything other than
 306	 * QH_STATE_IDLE, unless our caller is scan_async() or
 307	 * scan_intr().
 308	 */
 309	state = qh->qh_state;
 310	qh->qh_state = QH_STATE_COMPLETING;
 311	stopped = (state == QH_STATE_IDLE);
 312
 313 rescan:
 314	last = NULL;
 315	last_status = -EINPROGRESS;
 316	qh->dequeue_during_giveback = 0;
 317
 318	/* remove de-activated QTDs from front of queue.
 319	 * after faults (including short reads), cleanup this urb
 320	 * then let the queue advance.
 321	 * if queue is stopped, handles unlinks.
 322	 */
 323	list_for_each_safe (entry, tmp, &qh->qtd_list) {
 324		struct ehci_qtd	*qtd;
 325		struct urb	*urb;
 326		u32		token = 0;
 327
 328		qtd = list_entry (entry, struct ehci_qtd, qtd_list);
 329		urb = qtd->urb;
 330
 331		/* clean up any state from previous QTD ...*/
 332		if (last) {
 333			if (likely (last->urb != urb)) {
 334				ehci_urb_done(ehci, last->urb, last_status);
 335				last_status = -EINPROGRESS;
 336			}
 337			ehci_qtd_free (ehci, last);
 338			last = NULL;
 339		}
 340
 341		/* ignore urbs submitted during completions we reported */
 342		if (qtd == end)
 343			break;
 344
 345		/* hardware copies qtd out of qh overlay */
 346		rmb ();
 347		token = hc32_to_cpu(ehci, qtd->hw_token);
 348
 349		/* always clean up qtds the hc de-activated */
 350 retry_xacterr:
 351		if ((token & QTD_STS_ACTIVE) == 0) {
 352
 353			/* Report Data Buffer Error: non-fatal but useful */
 354			if (token & QTD_STS_DBE)
 355				ehci_dbg(ehci,
 356					"detected DataBufferErr for urb %p ep%d%s len %d, qtd %p [qh %p]\n",
 357					urb,
 358					usb_endpoint_num(&urb->ep->desc),
 359					usb_endpoint_dir_in(&urb->ep->desc) ? "in" : "out",
 360					urb->transfer_buffer_length,
 361					qtd,
 362					qh);
 363
 364			/* on STALL, error, and short reads this urb must
 365			 * complete and all its qtds must be recycled.
 366			 */
 367			if ((token & QTD_STS_HALT) != 0) {
 368
 369				/* retry transaction errors until we
 370				 * reach the software xacterr limit
 371				 */
 372				if ((token & QTD_STS_XACT) &&
 373						QTD_CERR(token) == 0 &&
 374						++qh->xacterrs < QH_XACTERR_MAX &&
 375						!urb->unlinked) {
 376					ehci_dbg(ehci,
 377	"detected XactErr len %zu/%zu retry %d\n",
 378	qtd->length - QTD_LENGTH(token), qtd->length, qh->xacterrs);
 379
 380					/* reset the token in the qtd and the
 381					 * qh overlay (which still contains
 382					 * the qtd) so that we pick up from
 383					 * where we left off
 384					 */
 385					token &= ~QTD_STS_HALT;
 386					token |= QTD_STS_ACTIVE |
 387							(EHCI_TUNE_CERR << 10);
 388					qtd->hw_token = cpu_to_hc32(ehci,
 389							token);
 390					wmb();
 391					hw->hw_token = cpu_to_hc32(ehci,
 392							token);
 393					goto retry_xacterr;
 394				}
 395				stopped = 1;
 396				qh->unlink_reason |= QH_UNLINK_HALTED;
 397
 398			/* magic dummy for some short reads; qh won't advance.
 399			 * that silicon quirk can kick in with this dummy too.
 400			 *
 401			 * other short reads won't stop the queue, including
 402			 * control transfers (status stage handles that) or
 403			 * most other single-qtd reads ... the queue stops if
 404			 * URB_SHORT_NOT_OK was set so the driver submitting
 405			 * the urbs could clean it up.
 406			 */
 407			} else if (IS_SHORT_READ (token)
 408					&& !(qtd->hw_alt_next
 409						& EHCI_LIST_END(ehci))) {
 410				stopped = 1;
 411				qh->unlink_reason |= QH_UNLINK_SHORT_READ;
 412			}
 413
 414		/* stop scanning when we reach qtds the hc is using */
 415		} else if (likely (!stopped
 416				&& ehci->rh_state >= EHCI_RH_RUNNING)) {
 417			break;
 418
 419		/* scan the whole queue for unlinks whenever it stops */
 420		} else {
 421			stopped = 1;
 422
 423			/* cancel everything if we halt, suspend, etc */
 424			if (ehci->rh_state < EHCI_RH_RUNNING) {
 425				last_status = -ESHUTDOWN;
 426				qh->unlink_reason |= QH_UNLINK_SHUTDOWN;
 427			}
 428
 429			/* this qtd is active; skip it unless a previous qtd
 430			 * for its urb faulted, or its urb was canceled.
 431			 */
 432			else if (last_status == -EINPROGRESS && !urb->unlinked)
 433				continue;
 434
 435			/*
 436			 * If this was the active qtd when the qh was unlinked
 437			 * and the overlay's token is active, then the overlay
 438			 * hasn't been written back to the qtd yet so use its
 439			 * token instead of the qtd's.  After the qtd is
 440			 * processed and removed, the overlay won't be valid
 441			 * any more.
 442			 */
 443			if (state == QH_STATE_IDLE &&
 444					qh->qtd_list.next == &qtd->qtd_list &&
 445					(hw->hw_token & ACTIVE_BIT(ehci))) {
 446				token = hc32_to_cpu(ehci, hw->hw_token);
 447				hw->hw_token &= ~ACTIVE_BIT(ehci);
 448				qh->should_be_inactive = 1;
 449
 450				/* An unlink may leave an incomplete
 451				 * async transaction in the TT buffer.
 452				 * We have to clear it.
 453				 */
 454				ehci_clear_tt_buffer(ehci, qh, urb, token);
 455			}
 456		}
 457
 458		/* unless we already know the urb's status, collect qtd status
 459		 * and update count of bytes transferred.  in common short read
 460		 * cases with only one data qtd (including control transfers),
 461		 * queue processing won't halt.  but with two or more qtds (for
 462		 * example, with a 32 KB transfer), when the first qtd gets a
 463		 * short read the second must be removed by hand.
 464		 */
 465		if (last_status == -EINPROGRESS) {
 466			last_status = qtd_copy_status(ehci, urb,
 467					qtd->length, token);
 468			if (last_status == -EREMOTEIO
 469					&& (qtd->hw_alt_next
 470						& EHCI_LIST_END(ehci)))
 471				last_status = -EINPROGRESS;
 472
 473			/* As part of low/full-speed endpoint-halt processing
 474			 * we must clear the TT buffer (11.17.5).
 475			 */
 476			if (unlikely(last_status != -EINPROGRESS &&
 477					last_status != -EREMOTEIO)) {
 478				/* The TT's in some hubs malfunction when they
 479				 * receive this request following a STALL (they
 480				 * stop sending isochronous packets).  Since a
 481				 * STALL can't leave the TT buffer in a busy
 482				 * state (if you believe Figures 11-48 - 11-51
 483				 * in the USB 2.0 spec), we won't clear the TT
 484				 * buffer in this case.  Strictly speaking this
 485				 * is a violation of the spec.
 486				 */
 487				if (last_status != -EPIPE)
 488					ehci_clear_tt_buffer(ehci, qh, urb,
 489							token);
 490			}
 491		}
 492
 493		/* if we're removing something not at the queue head,
 494		 * patch the hardware queue pointer.
 495		 */
 496		if (stopped && qtd->qtd_list.prev != &qh->qtd_list) {
 497			last = list_entry (qtd->qtd_list.prev,
 498					struct ehci_qtd, qtd_list);
 499			last->hw_next = qtd->hw_next;
 500		}
 501
 502		/* remove qtd; it's recycled after possible urb completion */
 503		list_del (&qtd->qtd_list);
 504		last = qtd;
 505
 506		/* reinit the xacterr counter for the next qtd */
 507		qh->xacterrs = 0;
 508	}
 509
 510	/* last urb's completion might still need calling */
 511	if (likely (last != NULL)) {
 512		ehci_urb_done(ehci, last->urb, last_status);
 513		ehci_qtd_free (ehci, last);
 514	}
 515
 516	/* Do we need to rescan for URBs dequeued during a giveback? */
 517	if (unlikely(qh->dequeue_during_giveback)) {
 518		/* If the QH is already unlinked, do the rescan now. */
 519		if (state == QH_STATE_IDLE)
 520			goto rescan;
 521
 522		/* Otherwise the caller must unlink the QH. */
 523	}
 524
 525	/* restore original state; caller must unlink or relink */
 526	qh->qh_state = state;
 527
 528	/* be sure the hardware's done with the qh before refreshing
 529	 * it after fault cleanup, or recovering from silicon wrongly
 530	 * overlaying the dummy qtd (which reduces DMA chatter).
 531	 *
 532	 * We won't refresh a QH that's linked (after the HC
 533	 * stopped the queue).  That avoids a race:
 534	 *  - HC reads first part of QH;
 535	 *  - CPU updates that first part and the token;
 536	 *  - HC reads rest of that QH, including token
 537	 * Result:  HC gets an inconsistent image, and then
 538	 * DMAs to/from the wrong memory (corrupting it).
 539	 *
 540	 * That should be rare for interrupt transfers,
 541	 * except maybe high bandwidth ...
 542	 */
 543	if (stopped != 0 || hw->hw_qtd_next == EHCI_LIST_END(ehci))
 544		qh->unlink_reason |= QH_UNLINK_DUMMY_OVERLAY;
 545
 546	/* Let the caller know if the QH needs to be unlinked. */
 547	return qh->unlink_reason;
 548}
 549
 550/*-------------------------------------------------------------------------*/
 551
 552/*
 553 * reverse of qh_urb_transaction:  free a list of TDs.
 554 * used for cleanup after errors, before HC sees an URB's TDs.
 555 */
 556static void qtd_list_free (
 557	struct ehci_hcd		*ehci,
 558	struct urb		*urb,
 559	struct list_head	*qtd_list
 560) {
 561	struct list_head	*entry, *temp;
 562
 563	list_for_each_safe (entry, temp, qtd_list) {
 564		struct ehci_qtd	*qtd;
 565
 566		qtd = list_entry (entry, struct ehci_qtd, qtd_list);
 567		list_del (&qtd->qtd_list);
 568		ehci_qtd_free (ehci, qtd);
 569	}
 570}
 571
 572/*
 573 * create a list of filled qtds for this URB; won't link into qh.
 574 */
 575static struct list_head *
 576qh_urb_transaction (
 577	struct ehci_hcd		*ehci,
 578	struct urb		*urb,
 579	struct list_head	*head,
 580	gfp_t			flags
 581) {
 582	struct ehci_qtd		*qtd, *qtd_prev;
 583	dma_addr_t		buf;
 584	int			len, this_sg_len, maxpacket;
 585	int			is_input;
 586	u32			token;
 587	int			i;
 588	struct scatterlist	*sg;
 589
 590	/*
 591	 * URBs map to sequences of QTDs:  one logical transaction
 592	 */
 593	qtd = ehci_qtd_alloc (ehci, flags);
 594	if (unlikely (!qtd))
 595		return NULL;
 596	list_add_tail (&qtd->qtd_list, head);
 597	qtd->urb = urb;
 598
 599	token = QTD_STS_ACTIVE;
 600	token |= (EHCI_TUNE_CERR << 10);
 601	/* for split transactions, SplitXState initialized to zero */
 602
 603	len = urb->transfer_buffer_length;
 604	is_input = usb_pipein (urb->pipe);
 605	if (usb_pipecontrol (urb->pipe)) {
 606		/* SETUP pid */
 607		qtd_fill(ehci, qtd, urb->setup_dma,
 608				sizeof (struct usb_ctrlrequest),
 609				token | (2 /* "setup" */ << 8), 8);
 610
 611		/* ... and always at least one more pid */
 612		token ^= QTD_TOGGLE;
 613		qtd_prev = qtd;
 614		qtd = ehci_qtd_alloc (ehci, flags);
 615		if (unlikely (!qtd))
 616			goto cleanup;
 617		qtd->urb = urb;
 618		qtd_prev->hw_next = QTD_NEXT(ehci, qtd->qtd_dma);
 619		list_add_tail (&qtd->qtd_list, head);
 620
 621		/* for zero length DATA stages, STATUS is always IN */
 622		if (len == 0)
 623			token |= (1 /* "in" */ << 8);
 624	}
 625
 626	/*
 627	 * data transfer stage:  buffer setup
 628	 */
 629	i = urb->num_mapped_sgs;
 630	if (len > 0 && i > 0) {
 631		sg = urb->sg;
 632		buf = sg_dma_address(sg);
 633
 634		/* urb->transfer_buffer_length may be smaller than the
 635		 * size of the scatterlist (or vice versa)
 636		 */
 637		this_sg_len = min_t(int, sg_dma_len(sg), len);
 638	} else {
 639		sg = NULL;
 640		buf = urb->transfer_dma;
 641		this_sg_len = len;
 642	}
 643
 644	if (is_input)
 645		token |= (1 /* "in" */ << 8);
 646	/* else it's already initted to "out" pid (0 << 8) */
 647
 648	maxpacket = usb_endpoint_maxp(&urb->ep->desc);
 649
 650	/*
 651	 * buffer gets wrapped in one or more qtds;
 652	 * last one may be "short" (including zero len)
 653	 * and may serve as a control status ack
 654	 */
 655	for (;;) {
 656		unsigned int this_qtd_len;
 657
 658		this_qtd_len = qtd_fill(ehci, qtd, buf, this_sg_len, token,
 659				maxpacket);
 660		this_sg_len -= this_qtd_len;
 661		len -= this_qtd_len;
 662		buf += this_qtd_len;
 663
 664		/*
 665		 * short reads advance to a "magic" dummy instead of the next
 666		 * qtd ... that forces the queue to stop, for manual cleanup.
 667		 * (this will usually be overridden later.)
 668		 */
 669		if (is_input)
 670			qtd->hw_alt_next = ehci->async->hw->hw_alt_next;
 671
 672		/* qh makes control packets use qtd toggle; maybe switch it */
 673		if ((maxpacket & (this_qtd_len + (maxpacket - 1))) == 0)
 674			token ^= QTD_TOGGLE;
 675
 676		if (likely(this_sg_len <= 0)) {
 677			if (--i <= 0 || len <= 0)
 678				break;
 679			sg = sg_next(sg);
 680			buf = sg_dma_address(sg);
 681			this_sg_len = min_t(int, sg_dma_len(sg), len);
 682		}
 683
 684		qtd_prev = qtd;
 685		qtd = ehci_qtd_alloc (ehci, flags);
 686		if (unlikely (!qtd))
 687			goto cleanup;
 688		qtd->urb = urb;
 689		qtd_prev->hw_next = QTD_NEXT(ehci, qtd->qtd_dma);
 690		list_add_tail (&qtd->qtd_list, head);
 691	}
 692
 693	/*
 694	 * unless the caller requires manual cleanup after short reads,
 695	 * have the alt_next mechanism keep the queue running after the
 696	 * last data qtd (the only one, for control and most other cases).
 697	 */
 698	if (likely ((urb->transfer_flags & URB_SHORT_NOT_OK) == 0
 699				|| usb_pipecontrol (urb->pipe)))
 700		qtd->hw_alt_next = EHCI_LIST_END(ehci);
 701
 702	/*
 703	 * control requests may need a terminating data "status" ack;
 704	 * other OUT ones may need a terminating short packet
 705	 * (zero length).
 706	 */
 707	if (likely (urb->transfer_buffer_length != 0)) {
 708		int	one_more = 0;
 709
 710		if (usb_pipecontrol (urb->pipe)) {
 711			one_more = 1;
 712			token ^= 0x0100;	/* "in" <--> "out"  */
 713			token |= QTD_TOGGLE;	/* force DATA1 */
 714		} else if (usb_pipeout(urb->pipe)
 715				&& (urb->transfer_flags & URB_ZERO_PACKET)
 716				&& !(urb->transfer_buffer_length % maxpacket)) {
 717			one_more = 1;
 718		}
 719		if (one_more) {
 720			qtd_prev = qtd;
 721			qtd = ehci_qtd_alloc (ehci, flags);
 722			if (unlikely (!qtd))
 723				goto cleanup;
 724			qtd->urb = urb;
 725			qtd_prev->hw_next = QTD_NEXT(ehci, qtd->qtd_dma);
 726			list_add_tail (&qtd->qtd_list, head);
 727
 728			/* never any data in such packets */
 729			qtd_fill(ehci, qtd, 0, 0, token, 0);
 730		}
 731	}
 732
 733	/* by default, enable interrupt on urb completion */
 734	if (likely (!(urb->transfer_flags & URB_NO_INTERRUPT)))
 735		qtd->hw_token |= cpu_to_hc32(ehci, QTD_IOC);
 736	return head;
 737
 738cleanup:
 739	qtd_list_free (ehci, urb, head);
 740	return NULL;
 741}
 742
 743/*-------------------------------------------------------------------------*/
 744
 745// Would be best to create all qh's from config descriptors,
 746// when each interface/altsetting is established.  Unlink
 747// any previous qh and cancel its urbs first; endpoints are
 748// implicitly reset then (data toggle too).
 749// That'd mean updating how usbcore talks to HCDs. (2.7?)
 750
 751
 752/*
 753 * Each QH holds a qtd list; a QH is used for everything except iso.
 754 *
 755 * For interrupt urbs, the scheduler must set the microframe scheduling
 756 * mask(s) each time the QH gets scheduled.  For highspeed, that's
 757 * just one microframe in the s-mask.  For split interrupt transactions
 758 * there are additional complications: c-mask, maybe FSTNs.
 759 */
 760static struct ehci_qh *
 761qh_make (
 762	struct ehci_hcd		*ehci,
 763	struct urb		*urb,
 764	gfp_t			flags
 765) {
 766	struct ehci_qh		*qh = ehci_qh_alloc (ehci, flags);
 767	struct usb_host_endpoint *ep;
 768	u32			info1 = 0, info2 = 0;
 769	int			is_input, type;
 770	int			maxp = 0;
 771	int			mult;
 772	struct usb_tt		*tt = urb->dev->tt;
 773	struct ehci_qh_hw	*hw;
 774
 775	if (!qh)
 776		return qh;
 777
 778	/*
 779	 * init endpoint/device data for this QH
 780	 */
 781	info1 |= usb_pipeendpoint (urb->pipe) << 8;
 782	info1 |= usb_pipedevice (urb->pipe) << 0;
 783
 784	is_input = usb_pipein (urb->pipe);
 785	type = usb_pipetype (urb->pipe);
 786	ep = usb_pipe_endpoint (urb->dev, urb->pipe);
 787	maxp = usb_endpoint_maxp (&ep->desc);
 788	mult = usb_endpoint_maxp_mult (&ep->desc);
 789
 790	/* 1024 byte maxpacket is a hardware ceiling.  High bandwidth
 791	 * acts like up to 3KB, but is built from smaller packets.
 792	 */
 793	if (maxp > 1024) {
 794		ehci_dbg(ehci, "bogus qh maxpacket %d\n", maxp);
 795		goto done;
 796	}
 797
 798	/* Compute interrupt scheduling parameters just once, and save.
 799	 * - allowing for high bandwidth, how many nsec/uframe are used?
 800	 * - split transactions need a second CSPLIT uframe; same question
 801	 * - splits also need a schedule gap (for full/low speed I/O)
 802	 * - qh has a polling interval
 803	 *
 804	 * For control/bulk requests, the HC or TT handles these.
 805	 */
 806	if (type == PIPE_INTERRUPT) {
 807		unsigned	tmp;
 808
 809		qh->ps.usecs = NS_TO_US(usb_calc_bus_time(USB_SPEED_HIGH,
 810				is_input, 0, mult * maxp));
 811		qh->ps.phase = NO_FRAME;
 812
 813		if (urb->dev->speed == USB_SPEED_HIGH) {
 814			qh->ps.c_usecs = 0;
 815			qh->gap_uf = 0;
 816
 817			if (urb->interval > 1 && urb->interval < 8) {
 818				/* NOTE interval 2 or 4 uframes could work.
 819				 * But interval 1 scheduling is simpler, and
 820				 * includes high bandwidth.
 821				 */
 822				urb->interval = 1;
 823			} else if (urb->interval > ehci->periodic_size << 3) {
 824				urb->interval = ehci->periodic_size << 3;
 825			}
 826			qh->ps.period = urb->interval >> 3;
 827
 828			/* period for bandwidth allocation */
 829			tmp = min_t(unsigned, EHCI_BANDWIDTH_SIZE,
 830					1 << (urb->ep->desc.bInterval - 1));
 831
 832			/* Allow urb->interval to override */
 833			qh->ps.bw_uperiod = min_t(unsigned, tmp, urb->interval);
 834			qh->ps.bw_period = qh->ps.bw_uperiod >> 3;
 835		} else {
 836			int		think_time;
 837
 838			/* gap is f(FS/LS transfer times) */
 839			qh->gap_uf = 1 + usb_calc_bus_time (urb->dev->speed,
 840					is_input, 0, maxp) / (125 * 1000);
 841
 842			/* FIXME this just approximates SPLIT/CSPLIT times */
 843			if (is_input) {		// SPLIT, gap, CSPLIT+DATA
 844				qh->ps.c_usecs = qh->ps.usecs + HS_USECS(0);
 845				qh->ps.usecs = HS_USECS(1);
 846			} else {		// SPLIT+DATA, gap, CSPLIT
 847				qh->ps.usecs += HS_USECS(1);
 848				qh->ps.c_usecs = HS_USECS(0);
 849			}
 850
 851			think_time = tt ? tt->think_time : 0;
 852			qh->ps.tt_usecs = NS_TO_US(think_time +
 853					usb_calc_bus_time (urb->dev->speed,
 854					is_input, 0, maxp));
 855			if (urb->interval > ehci->periodic_size)
 856				urb->interval = ehci->periodic_size;
 857			qh->ps.period = urb->interval;
 858
 859			/* period for bandwidth allocation */
 860			tmp = min_t(unsigned, EHCI_BANDWIDTH_FRAMES,
 861					urb->ep->desc.bInterval);
 862			tmp = rounddown_pow_of_two(tmp);
 863
 864			/* Allow urb->interval to override */
 865			qh->ps.bw_period = min_t(unsigned, tmp, urb->interval);
 866			qh->ps.bw_uperiod = qh->ps.bw_period << 3;
 867		}
 868	}
 869
 870	/* support for tt scheduling, and access to toggles */
 871	qh->ps.udev = urb->dev;
 872	qh->ps.ep = urb->ep;
 873
 874	/* using TT? */
 875	switch (urb->dev->speed) {
 876	case USB_SPEED_LOW:
 877		info1 |= QH_LOW_SPEED;
 878		fallthrough;
 879
 880	case USB_SPEED_FULL:
 881		/* EPS 0 means "full" */
 882		if (type != PIPE_INTERRUPT)
 883			info1 |= (EHCI_TUNE_RL_TT << 28);
 884		if (type == PIPE_CONTROL) {
 885			info1 |= QH_CONTROL_EP;		/* for TT */
 886			info1 |= QH_TOGGLE_CTL;		/* toggle from qtd */
 887		}
 888		info1 |= maxp << 16;
 889
 890		info2 |= (EHCI_TUNE_MULT_TT << 30);
 891
 892		/* Some Freescale processors have an erratum in which the
 893		 * port number in the queue head was 0..N-1 instead of 1..N.
 894		 */
 895		if (ehci_has_fsl_portno_bug(ehci))
 896			info2 |= (urb->dev->ttport-1) << 23;
 897		else
 898			info2 |= urb->dev->ttport << 23;
 899
 900		/* set the address of the TT; for TDI's integrated
 901		 * root hub tt, leave it zeroed.
 902		 */
 903		if (tt && tt->hub != ehci_to_hcd(ehci)->self.root_hub)
 904			info2 |= tt->hub->devnum << 16;
 905
 906		/* NOTE:  if (PIPE_INTERRUPT) { scheduler sets c-mask } */
 907
 908		break;
 909
 910	case USB_SPEED_HIGH:		/* no TT involved */
 911		info1 |= QH_HIGH_SPEED;
 912		if (type == PIPE_CONTROL) {
 913			info1 |= (EHCI_TUNE_RL_HS << 28);
 914			info1 |= 64 << 16;	/* usb2 fixed maxpacket */
 915			info1 |= QH_TOGGLE_CTL;	/* toggle from qtd */
 916			info2 |= (EHCI_TUNE_MULT_HS << 30);
 917		} else if (type == PIPE_BULK) {
 918			info1 |= (EHCI_TUNE_RL_HS << 28);
 919			/* The USB spec says that high speed bulk endpoints
 920			 * always use 512 byte maxpacket.  But some device
 921			 * vendors decided to ignore that, and MSFT is happy
 922			 * to help them do so.  So now people expect to use
 923			 * such nonconformant devices with Linux too; sigh.
 924			 */
 925			info1 |= maxp << 16;
 926			info2 |= (EHCI_TUNE_MULT_HS << 30);
 927		} else {		/* PIPE_INTERRUPT */
 928			info1 |= maxp << 16;
 929			info2 |= mult << 30;
 930		}
 931		break;
 932	default:
 933		ehci_dbg(ehci, "bogus dev %p speed %d\n", urb->dev,
 934			urb->dev->speed);
 935done:
 936		qh_destroy(ehci, qh);
 937		return NULL;
 938	}
 939
 940	/* NOTE:  if (PIPE_INTERRUPT) { scheduler sets s-mask } */
 941
 942	/* init as live, toggle clear */
 943	qh->qh_state = QH_STATE_IDLE;
 944	hw = qh->hw;
 945	hw->hw_info1 = cpu_to_hc32(ehci, info1);
 946	hw->hw_info2 = cpu_to_hc32(ehci, info2);
 947	qh->is_out = !is_input;
 948	usb_settoggle (urb->dev, usb_pipeendpoint (urb->pipe), !is_input, 1);
 949	return qh;
 950}
 951
 952/*-------------------------------------------------------------------------*/
 953
 954static void enable_async(struct ehci_hcd *ehci)
 955{
 956	if (ehci->async_count++)
 957		return;
 958
 959	/* Stop waiting to turn off the async schedule */
 960	ehci->enabled_hrtimer_events &= ~BIT(EHCI_HRTIMER_DISABLE_ASYNC);
 961
 962	/* Don't start the schedule until ASS is 0 */
 963	ehci_poll_ASS(ehci);
 964	turn_on_io_watchdog(ehci);
 965}
 966
 967static void disable_async(struct ehci_hcd *ehci)
 968{
 969	if (--ehci->async_count)
 970		return;
 971
 972	/* The async schedule and unlink lists are supposed to be empty */
 973	WARN_ON(ehci->async->qh_next.qh || !list_empty(&ehci->async_unlink) ||
 974			!list_empty(&ehci->async_idle));
 975
 976	/* Don't turn off the schedule until ASS is 1 */
 977	ehci_poll_ASS(ehci);
 978}
 979
 980/* move qh (and its qtds) onto async queue; maybe enable queue.  */
 981
 982static void qh_link_async (struct ehci_hcd *ehci, struct ehci_qh *qh)
 983{
 984	__hc32		dma = QH_NEXT(ehci, qh->qh_dma);
 985	struct ehci_qh	*head;
 986
 987	/* Don't link a QH if there's a Clear-TT-Buffer pending */
 988	if (unlikely(qh->clearing_tt))
 989		return;
 990
 991	WARN_ON(qh->qh_state != QH_STATE_IDLE);
 992
 993	/* clear halt and/or toggle; and maybe recover from silicon quirk */
 994	qh_refresh(ehci, qh);
 995
 996	/* splice right after start */
 997	head = ehci->async;
 998	qh->qh_next = head->qh_next;
 999	qh->hw->hw_next = head->hw->hw_next;
1000	wmb ();
1001
1002	head->qh_next.qh = qh;
1003	head->hw->hw_next = dma;
1004
1005	qh->qh_state = QH_STATE_LINKED;
1006	qh->xacterrs = 0;
1007	qh->unlink_reason = 0;
1008	/* qtd completions reported later by interrupt */
1009
1010	enable_async(ehci);
1011}
1012
1013/*-------------------------------------------------------------------------*/
1014
1015/*
1016 * For control/bulk/interrupt, return QH with these TDs appended.
1017 * Allocates and initializes the QH if necessary.
1018 * Returns null if it can't allocate a QH it needs to.
1019 * If the QH has TDs (urbs) already, that's great.
1020 */
1021static struct ehci_qh *qh_append_tds (
1022	struct ehci_hcd		*ehci,
1023	struct urb		*urb,
1024	struct list_head	*qtd_list,
1025	int			epnum,
1026	void			**ptr
1027)
1028{
1029	struct ehci_qh		*qh = NULL;
1030	__hc32			qh_addr_mask = cpu_to_hc32(ehci, 0x7f);
1031
1032	qh = (struct ehci_qh *) *ptr;
1033	if (unlikely (qh == NULL)) {
1034		/* can't sleep here, we have ehci->lock... */
1035		qh = qh_make (ehci, urb, GFP_ATOMIC);
1036		*ptr = qh;
1037	}
1038	if (likely (qh != NULL)) {
1039		struct ehci_qtd	*qtd;
1040
1041		if (unlikely (list_empty (qtd_list)))
1042			qtd = NULL;
1043		else
1044			qtd = list_entry (qtd_list->next, struct ehci_qtd,
1045					qtd_list);
1046
1047		/* control qh may need patching ... */
1048		if (unlikely (epnum == 0)) {
1049
1050                        /* usb_reset_device() briefly reverts to address 0 */
1051                        if (usb_pipedevice (urb->pipe) == 0)
1052				qh->hw->hw_info1 &= ~qh_addr_mask;
1053		}
1054
1055		/* just one way to queue requests: swap with the dummy qtd.
1056		 * only hc or qh_refresh() ever modify the overlay.
1057		 */
1058		if (likely (qtd != NULL)) {
1059			struct ehci_qtd		*dummy;
1060			dma_addr_t		dma;
1061			__hc32			token;
1062
1063			/* to avoid racing the HC, use the dummy td instead of
1064			 * the first td of our list (becomes new dummy).  both
1065			 * tds stay deactivated until we're done, when the
1066			 * HC is allowed to fetch the old dummy (4.10.2).
1067			 */
1068			token = qtd->hw_token;
1069			qtd->hw_token = HALT_BIT(ehci);
1070
1071			dummy = qh->dummy;
1072
1073			dma = dummy->qtd_dma;
1074			*dummy = *qtd;
1075			dummy->qtd_dma = dma;
1076
1077			list_del (&qtd->qtd_list);
1078			list_add (&dummy->qtd_list, qtd_list);
1079			list_splice_tail(qtd_list, &qh->qtd_list);
1080
1081			ehci_qtd_init(ehci, qtd, qtd->qtd_dma);
1082			qh->dummy = qtd;
1083
1084			/* hc must see the new dummy at list end */
1085			dma = qtd->qtd_dma;
1086			qtd = list_entry (qh->qtd_list.prev,
1087					struct ehci_qtd, qtd_list);
1088			qtd->hw_next = QTD_NEXT(ehci, dma);
1089
1090			/* let the hc process these next qtds */
1091			wmb ();
1092			dummy->hw_token = token;
1093
1094			urb->hcpriv = qh;
1095		}
1096	}
1097	return qh;
1098}
1099
1100/*-------------------------------------------------------------------------*/
1101
1102static int
1103submit_async (
1104	struct ehci_hcd		*ehci,
1105	struct urb		*urb,
1106	struct list_head	*qtd_list,
1107	gfp_t			mem_flags
1108) {
1109	int			epnum;
1110	unsigned long		flags;
1111	struct ehci_qh		*qh = NULL;
1112	int			rc;
1113
1114	epnum = urb->ep->desc.bEndpointAddress;
1115
1116#ifdef EHCI_URB_TRACE
1117	{
1118		struct ehci_qtd *qtd;
1119		qtd = list_entry(qtd_list->next, struct ehci_qtd, qtd_list);
1120		ehci_dbg(ehci,
1121			 "%s %s urb %p ep%d%s len %d, qtd %p [qh %p]\n",
1122			 __func__, urb->dev->devpath, urb,
1123			 epnum & 0x0f, (epnum & USB_DIR_IN) ? "in" : "out",
1124			 urb->transfer_buffer_length,
1125			 qtd, urb->ep->hcpriv);
1126	}
1127#endif
1128
1129	spin_lock_irqsave (&ehci->lock, flags);
1130	if (unlikely(!HCD_HW_ACCESSIBLE(ehci_to_hcd(ehci)))) {
1131		rc = -ESHUTDOWN;
1132		goto done;
1133	}
1134	rc = usb_hcd_link_urb_to_ep(ehci_to_hcd(ehci), urb);
1135	if (unlikely(rc))
1136		goto done;
1137
1138	qh = qh_append_tds(ehci, urb, qtd_list, epnum, &urb->ep->hcpriv);
1139	if (unlikely(qh == NULL)) {
1140		usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
1141		rc = -ENOMEM;
1142		goto done;
1143	}
1144
1145	/* Control/bulk operations through TTs don't need scheduling,
1146	 * the HC and TT handle it when the TT has a buffer ready.
1147	 */
1148	if (likely (qh->qh_state == QH_STATE_IDLE))
1149		qh_link_async(ehci, qh);
1150 done:
1151	spin_unlock_irqrestore (&ehci->lock, flags);
1152	if (unlikely (qh == NULL))
1153		qtd_list_free (ehci, urb, qtd_list);
1154	return rc;
1155}
1156
1157/*-------------------------------------------------------------------------*/
1158#ifdef CONFIG_USB_HCD_TEST_MODE
1159/*
1160 * This function creates the qtds and submits them for the
1161 * SINGLE_STEP_SET_FEATURE Test.
1162 * This is done in two parts: first SETUP req for GetDesc is sent then
1163 * 15 seconds later, the IN stage for GetDesc starts to req data from dev
1164 *
1165 * is_setup : i/p argument decides which of the two stage needs to be
1166 * performed; TRUE - SETUP and FALSE - IN+STATUS
1167 * Returns 0 if success
1168 */
1169static int ehci_submit_single_step_set_feature(
1170	struct usb_hcd  *hcd,
1171	struct urb      *urb,
1172	int             is_setup
1173) {
1174	struct ehci_hcd		*ehci = hcd_to_ehci(hcd);
1175	struct list_head	qtd_list;
1176	struct list_head	*head;
1177
1178	struct ehci_qtd		*qtd, *qtd_prev;
1179	dma_addr_t		buf;
1180	int			len, maxpacket;
1181	u32			token;
1182
1183	INIT_LIST_HEAD(&qtd_list);
1184	head = &qtd_list;
1185
1186	/* URBs map to sequences of QTDs:  one logical transaction */
1187	qtd = ehci_qtd_alloc(ehci, GFP_KERNEL);
1188	if (unlikely(!qtd))
1189		return -1;
1190	list_add_tail(&qtd->qtd_list, head);
1191	qtd->urb = urb;
1192
1193	token = QTD_STS_ACTIVE;
1194	token |= (EHCI_TUNE_CERR << 10);
1195
1196	len = urb->transfer_buffer_length;
1197	/*
1198	 * Check if the request is to perform just the SETUP stage (getDesc)
1199	 * as in SINGLE_STEP_SET_FEATURE test, DATA stage (IN) happens
1200	 * 15 secs after the setup
1201	 */
1202	if (is_setup) {
1203		/* SETUP pid, and interrupt after SETUP completion */
1204		qtd_fill(ehci, qtd, urb->setup_dma,
1205				sizeof(struct usb_ctrlrequest),
1206				QTD_IOC | token | (2 /* "setup" */ << 8), 8);
1207
1208		submit_async(ehci, urb, &qtd_list, GFP_ATOMIC);
1209		return 0; /*Return now; we shall come back after 15 seconds*/
1210	}
1211
1212	/*
1213	 * IN: data transfer stage:  buffer setup : start the IN txn phase for
1214	 * the get_Desc SETUP which was sent 15seconds back
1215	 */
1216	token ^= QTD_TOGGLE;   /*We need to start IN with DATA-1 Pid-sequence*/
1217	buf = urb->transfer_dma;
1218
1219	token |= (1 /* "in" */ << 8);  /*This is IN stage*/
1220
1221	maxpacket = usb_endpoint_maxp(&urb->ep->desc);
1222
1223	qtd_fill(ehci, qtd, buf, len, token, maxpacket);
1224
1225	/*
1226	 * Our IN phase shall always be a short read; so keep the queue running
1227	 * and let it advance to the next qtd which zero length OUT status
1228	 */
1229	qtd->hw_alt_next = EHCI_LIST_END(ehci);
1230
1231	/* STATUS stage for GetDesc control request */
1232	token ^= 0x0100;        /* "in" <--> "out"  */
1233	token |= QTD_TOGGLE;    /* force DATA1 */
1234
1235	qtd_prev = qtd;
1236	qtd = ehci_qtd_alloc(ehci, GFP_ATOMIC);
1237	if (unlikely(!qtd))
1238		goto cleanup;
1239	qtd->urb = urb;
1240	qtd_prev->hw_next = QTD_NEXT(ehci, qtd->qtd_dma);
1241	list_add_tail(&qtd->qtd_list, head);
1242
1243	/* Interrupt after STATUS completion */
1244	qtd_fill(ehci, qtd, 0, 0, token | QTD_IOC, 0);
1245
1246	submit_async(ehci, urb, &qtd_list, GFP_KERNEL);
1247
1248	return 0;
1249
1250cleanup:
1251	qtd_list_free(ehci, urb, head);
1252	return -1;
1253}
1254#endif /* CONFIG_USB_HCD_TEST_MODE */
1255
1256/*-------------------------------------------------------------------------*/
1257
1258static void single_unlink_async(struct ehci_hcd *ehci, struct ehci_qh *qh)
1259{
1260	struct ehci_qh		*prev;
1261
1262	/* Add to the end of the list of QHs waiting for the next IAAD */
1263	qh->qh_state = QH_STATE_UNLINK_WAIT;
1264	list_add_tail(&qh->unlink_node, &ehci->async_unlink);
1265
1266	/* Unlink it from the schedule */
1267	prev = ehci->async;
1268	while (prev->qh_next.qh != qh)
1269		prev = prev->qh_next.qh;
1270
1271	prev->hw->hw_next = qh->hw->hw_next;
1272	prev->qh_next = qh->qh_next;
1273	if (ehci->qh_scan_next == qh)
1274		ehci->qh_scan_next = qh->qh_next.qh;
1275}
1276
1277static void start_iaa_cycle(struct ehci_hcd *ehci)
1278{
1279	/* If the controller isn't running, we don't have to wait for it */
1280	if (unlikely(ehci->rh_state < EHCI_RH_RUNNING)) {
1281		end_unlink_async(ehci);
1282
1283	/* Otherwise start a new IAA cycle if one isn't already running */
1284	} else if (ehci->rh_state == EHCI_RH_RUNNING &&
1285			!ehci->iaa_in_progress) {
1286
1287		/* Make sure the unlinks are all visible to the hardware */
1288		wmb();
1289
1290		ehci_writel(ehci, ehci->command | CMD_IAAD,
1291				&ehci->regs->command);
1292		ehci_readl(ehci, &ehci->regs->command);
1293		ehci->iaa_in_progress = true;
1294		ehci_enable_event(ehci, EHCI_HRTIMER_IAA_WATCHDOG, true);
1295	}
1296}
1297
1298static void end_iaa_cycle(struct ehci_hcd *ehci)
1299{
1300	if (ehci->has_synopsys_hc_bug)
1301		ehci_writel(ehci, (u32) ehci->async->qh_dma,
1302			    &ehci->regs->async_next);
1303
1304	/* The current IAA cycle has ended */
1305	ehci->iaa_in_progress = false;
1306
1307	end_unlink_async(ehci);
1308}
1309
1310/* See if the async qh for the qtds being unlinked are now gone from the HC */
1311
1312static void end_unlink_async(struct ehci_hcd *ehci)
1313{
1314	struct ehci_qh		*qh;
1315	bool			early_exit;
1316
1317	if (list_empty(&ehci->async_unlink))
1318		return;
1319	qh = list_first_entry(&ehci->async_unlink, struct ehci_qh,
1320			unlink_node);	/* QH whose IAA cycle just ended */
1321
1322	/*
1323	 * If async_unlinking is set then this routine is already running,
1324	 * either on the stack or on another CPU.
1325	 */
1326	early_exit = ehci->async_unlinking;
1327
1328	/* If the controller isn't running, process all the waiting QHs */
1329	if (ehci->rh_state < EHCI_RH_RUNNING)
1330		list_splice_tail_init(&ehci->async_unlink, &ehci->async_idle);
1331
1332	/*
1333	 * Intel (?) bug: The HC can write back the overlay region even
1334	 * after the IAA interrupt occurs.  In self-defense, always go
1335	 * through two IAA cycles for each QH.
1336	 */
1337	else if (qh->qh_state == QH_STATE_UNLINK) {
1338		/*
1339		 * Second IAA cycle has finished.  Process only the first
1340		 * waiting QH (NVIDIA (?) bug).
1341		 */
1342		list_move_tail(&qh->unlink_node, &ehci->async_idle);
1343	}
1344
1345	/*
1346	 * AMD/ATI (?) bug: The HC can continue to use an active QH long
1347	 * after the IAA interrupt occurs.  To prevent problems, QHs that
1348	 * may still be active will wait until 2 ms have passed with no
1349	 * change to the hw_current and hw_token fields (this delay occurs
1350	 * between the two IAA cycles).
1351	 *
1352	 * The EHCI spec (4.8.2) says that active QHs must not be removed
1353	 * from the async schedule and recommends waiting until the QH
1354	 * goes inactive.  This is ridiculous because the QH will _never_
1355	 * become inactive if the endpoint NAKs indefinitely.
1356	 */
1357
1358	/* Some reasons for unlinking guarantee the QH can't be active */
1359	else if (qh->unlink_reason & (QH_UNLINK_HALTED |
1360			QH_UNLINK_SHORT_READ | QH_UNLINK_DUMMY_OVERLAY))
1361		goto DelayDone;
1362
1363	/* The QH can't be active if the queue was and still is empty... */
1364	else if	((qh->unlink_reason & QH_UNLINK_QUEUE_EMPTY) &&
1365			list_empty(&qh->qtd_list))
1366		goto DelayDone;
1367
1368	/* ... or if the QH has halted */
1369	else if	(qh->hw->hw_token & cpu_to_hc32(ehci, QTD_STS_HALT))
1370		goto DelayDone;
1371
1372	/* Otherwise we have to wait until the QH stops changing */
1373	else {
1374		__hc32		qh_current, qh_token;
1375
1376		qh_current = qh->hw->hw_current;
1377		qh_token = qh->hw->hw_token;
1378		if (qh_current != ehci->old_current ||
1379				qh_token != ehci->old_token) {
1380			ehci->old_current = qh_current;
1381			ehci->old_token = qh_token;
1382			ehci_enable_event(ehci,
1383					EHCI_HRTIMER_ACTIVE_UNLINK, true);
1384			return;
1385		}
1386 DelayDone:
1387		qh->qh_state = QH_STATE_UNLINK;
1388		early_exit = true;
1389	}
1390	ehci->old_current = ~0;		/* Prepare for next QH */
1391
1392	/* Start a new IAA cycle if any QHs are waiting for it */
1393	if (!list_empty(&ehci->async_unlink))
1394		start_iaa_cycle(ehci);
1395
1396	/*
1397	 * Don't allow nesting or concurrent calls,
1398	 * or wait for the second IAA cycle for the next QH.
1399	 */
1400	if (early_exit)
1401		return;
1402
1403	/* Process the idle QHs */
1404	ehci->async_unlinking = true;
1405	while (!list_empty(&ehci->async_idle)) {
1406		qh = list_first_entry(&ehci->async_idle, struct ehci_qh,
1407				unlink_node);
1408		list_del(&qh->unlink_node);
1409
1410		qh->qh_state = QH_STATE_IDLE;
1411		qh->qh_next.qh = NULL;
1412
1413		if (!list_empty(&qh->qtd_list))
1414			qh_completions(ehci, qh);
1415		if (!list_empty(&qh->qtd_list) &&
1416				ehci->rh_state == EHCI_RH_RUNNING)
1417			qh_link_async(ehci, qh);
1418		disable_async(ehci);
1419	}
1420	ehci->async_unlinking = false;
1421}
1422
1423static void start_unlink_async(struct ehci_hcd *ehci, struct ehci_qh *qh);
1424
1425static void unlink_empty_async(struct ehci_hcd *ehci)
1426{
1427	struct ehci_qh		*qh;
1428	struct ehci_qh		*qh_to_unlink = NULL;
1429	int			count = 0;
1430
1431	/* Find the last async QH which has been empty for a timer cycle */
1432	for (qh = ehci->async->qh_next.qh; qh; qh = qh->qh_next.qh) {
1433		if (list_empty(&qh->qtd_list) &&
1434				qh->qh_state == QH_STATE_LINKED) {
1435			++count;
1436			if (qh->unlink_cycle != ehci->async_unlink_cycle)
1437				qh_to_unlink = qh;
1438		}
1439	}
1440
1441	/* If nothing else is being unlinked, unlink the last empty QH */
1442	if (list_empty(&ehci->async_unlink) && qh_to_unlink) {
1443		qh_to_unlink->unlink_reason |= QH_UNLINK_QUEUE_EMPTY;
1444		start_unlink_async(ehci, qh_to_unlink);
1445		--count;
1446	}
1447
1448	/* Other QHs will be handled later */
1449	if (count > 0) {
1450		ehci_enable_event(ehci, EHCI_HRTIMER_ASYNC_UNLINKS, true);
1451		++ehci->async_unlink_cycle;
1452	}
1453}
1454
1455#ifdef	CONFIG_PM
1456
1457/* The root hub is suspended; unlink all the async QHs */
1458static void unlink_empty_async_suspended(struct ehci_hcd *ehci)
1459{
1460	struct ehci_qh		*qh;
1461
1462	while (ehci->async->qh_next.qh) {
1463		qh = ehci->async->qh_next.qh;
1464		WARN_ON(!list_empty(&qh->qtd_list));
1465		single_unlink_async(ehci, qh);
1466	}
1467}
1468
1469#endif
1470
1471/* makes sure the async qh will become idle */
1472/* caller must own ehci->lock */
1473
1474static void start_unlink_async(struct ehci_hcd *ehci, struct ehci_qh *qh)
1475{
1476	/* If the QH isn't linked then there's nothing we can do. */
1477	if (qh->qh_state != QH_STATE_LINKED)
1478		return;
1479
1480	single_unlink_async(ehci, qh);
1481	start_iaa_cycle(ehci);
1482}
1483
1484/*-------------------------------------------------------------------------*/
1485
1486static void scan_async (struct ehci_hcd *ehci)
1487{
1488	struct ehci_qh		*qh;
1489	bool			check_unlinks_later = false;
1490
1491	ehci->qh_scan_next = ehci->async->qh_next.qh;
1492	while (ehci->qh_scan_next) {
1493		qh = ehci->qh_scan_next;
1494		ehci->qh_scan_next = qh->qh_next.qh;
1495
1496		/* clean any finished work for this qh */
1497		if (!list_empty(&qh->qtd_list)) {
1498			int temp;
1499
1500			/*
1501			 * Unlinks could happen here; completion reporting
1502			 * drops the lock.  That's why ehci->qh_scan_next
1503			 * always holds the next qh to scan; if the next qh
1504			 * gets unlinked then ehci->qh_scan_next is adjusted
1505			 * in single_unlink_async().
1506			 */
1507			temp = qh_completions(ehci, qh);
1508			if (unlikely(temp)) {
1509				start_unlink_async(ehci, qh);
1510			} else if (list_empty(&qh->qtd_list)
1511					&& qh->qh_state == QH_STATE_LINKED) {
1512				qh->unlink_cycle = ehci->async_unlink_cycle;
1513				check_unlinks_later = true;
1514			}
1515		}
1516	}
1517
1518	/*
1519	 * Unlink empty entries, reducing DMA usage as well
1520	 * as HCD schedule-scanning costs.  Delay for any qh
1521	 * we just scanned, there's a not-unusual case that it
1522	 * doesn't stay idle for long.
1523	 */
1524	if (check_unlinks_later && ehci->rh_state == EHCI_RH_RUNNING &&
1525			!(ehci->enabled_hrtimer_events &
1526				BIT(EHCI_HRTIMER_ASYNC_UNLINKS))) {
1527		ehci_enable_event(ehci, EHCI_HRTIMER_ASYNC_UNLINKS, true);
1528		++ehci->async_unlink_cycle;
1529	}
1530}