xref: /openbmc/linux/drivers/usb/musb/musb_host.c (revision 384740dc)
1 /*
2  * MUSB OTG driver host support
3  *
4  * Copyright 2005 Mentor Graphics Corporation
5  * Copyright (C) 2005-2006 by Texas Instruments
6  * Copyright (C) 2006-2007 Nokia Corporation
7  *
8  * This program is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU General Public License
10  * version 2 as published by the Free Software Foundation.
11  *
12  * This program is distributed in the hope that it will be useful, but
13  * WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15  * General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with this program; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
20  * 02110-1301 USA
21  *
22  * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
23  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
24  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
25  * NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
27  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
28  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
29  * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
31  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32  *
33  */
34 
35 #include <linux/module.h>
36 #include <linux/kernel.h>
37 #include <linux/delay.h>
38 #include <linux/sched.h>
39 #include <linux/slab.h>
40 #include <linux/errno.h>
41 #include <linux/init.h>
42 #include <linux/list.h>
43 
44 #include "musb_core.h"
45 #include "musb_host.h"
46 
47 
48 /* MUSB HOST status 22-mar-2006
49  *
50  * - There's still lots of partial code duplication for fault paths, so
51  *   they aren't handled as consistently as they need to be.
52  *
53  * - PIO mostly behaved when last tested.
54  *     + including ep0, with all usbtest cases 9, 10
55  *     + usbtest 14 (ep0out) doesn't seem to run at all
56  *     + double buffered OUT/TX endpoints saw stalls(!) with certain usbtest
57  *       configurations, but otherwise double buffering passes basic tests.
58  *     + for 2.6.N, for N > ~10, needs API changes for hcd framework.
59  *
60  * - DMA (CPPI) ... partially behaves, not currently recommended
61  *     + about 1/15 the speed of typical EHCI implementations (PCI)
62  *     + RX, all too often reqpkt seems to misbehave after tx
63  *     + TX, no known issues (other than evident silicon issue)
64  *
65  * - DMA (Mentor/OMAP) ...has at least toggle update problems
66  *
67  * - Still no traffic scheduling code to make NAKing for bulk or control
68  *   transfers unable to starve other requests; or to make efficient use
69  *   of hardware with periodic transfers.  (Note that network drivers
70  *   commonly post bulk reads that stay pending for a long time; these
71  *   would make very visible trouble.)
72  *
73  * - Not tested with HNP, but some SRP paths seem to behave.
74  *
75  * NOTE 24-August-2006:
76  *
77  * - Bulk traffic finally uses both sides of hardware ep1, freeing up an
78  *   extra endpoint for periodic use enabling hub + keybd + mouse.  That
79  *   mostly works, except that with "usbnet" it's easy to trigger cases
80  *   with "ping" where RX loses.  (a) ping to davinci, even "ping -f",
81  *   fine; but (b) ping _from_ davinci, even "ping -c 1", ICMP RX loses
82  *   although ARP RX wins.  (That test was done with a full speed link.)
83  */
84 
85 
86 /*
87  * NOTE on endpoint usage:
88  *
89  * CONTROL transfers all go through ep0.  BULK ones go through dedicated IN
90  * and OUT endpoints ... hardware is dedicated for those "async" queue(s).
91  *
92  * (Yes, bulk _could_ use more of the endpoints than that, and would even
93  * benefit from it ... one remote device may easily be NAKing while others
94  * need to perform transfers in that same direction.  The same thing could
95  * be done in software though, assuming dma cooperates.)
96  *
97  * INTERUPPT and ISOCHRONOUS transfers are scheduled to the other endpoints.
98  * So far that scheduling is both dumb and optimistic:  the endpoint will be
99  * "claimed" until its software queue is no longer refilled.  No multiplexing
100  * of transfers between endpoints, or anything clever.
101  */
102 
103 
104 static void musb_ep_program(struct musb *musb, u8 epnum,
105 			struct urb *urb, unsigned int nOut,
106 			u8 *buf, u32 len);
107 
108 /*
109  * Clear TX fifo. Needed to avoid BABBLE errors.
110  */
111 static inline void musb_h_tx_flush_fifo(struct musb_hw_ep *ep)
112 {
113 	void __iomem	*epio = ep->regs;
114 	u16		csr;
115 	int		retries = 1000;
116 
117 	csr = musb_readw(epio, MUSB_TXCSR);
118 	while (csr & MUSB_TXCSR_FIFONOTEMPTY) {
119 		DBG(5, "Host TX FIFONOTEMPTY csr: %02x\n", csr);
120 		csr |= MUSB_TXCSR_FLUSHFIFO;
121 		musb_writew(epio, MUSB_TXCSR, csr);
122 		csr = musb_readw(epio, MUSB_TXCSR);
123 		if (retries-- < 1) {
124 			ERR("Could not flush host TX fifo: csr: %04x\n", csr);
125 			return;
126 		}
127 		mdelay(1);
128 	}
129 }
130 
131 /*
132  * Start transmit. Caller is responsible for locking shared resources.
133  * musb must be locked.
134  */
135 static inline void musb_h_tx_start(struct musb_hw_ep *ep)
136 {
137 	u16	txcsr;
138 
139 	/* NOTE: no locks here; caller should lock and select EP */
140 	if (ep->epnum) {
141 		txcsr = musb_readw(ep->regs, MUSB_TXCSR);
142 		txcsr |= MUSB_TXCSR_TXPKTRDY | MUSB_TXCSR_H_WZC_BITS;
143 		musb_writew(ep->regs, MUSB_TXCSR, txcsr);
144 	} else {
145 		txcsr = MUSB_CSR0_H_SETUPPKT | MUSB_CSR0_TXPKTRDY;
146 		musb_writew(ep->regs, MUSB_CSR0, txcsr);
147 	}
148 
149 }
150 
151 static inline void cppi_host_txdma_start(struct musb_hw_ep *ep)
152 {
153 	u16	txcsr;
154 
155 	/* NOTE: no locks here; caller should lock and select EP */
156 	txcsr = musb_readw(ep->regs, MUSB_TXCSR);
157 	txcsr |= MUSB_TXCSR_DMAENAB | MUSB_TXCSR_H_WZC_BITS;
158 	musb_writew(ep->regs, MUSB_TXCSR, txcsr);
159 }
160 
161 /*
162  * Start the URB at the front of an endpoint's queue
163  * end must be claimed from the caller.
164  *
165  * Context: controller locked, irqs blocked
166  */
167 static void
168 musb_start_urb(struct musb *musb, int is_in, struct musb_qh *qh)
169 {
170 	u16			frame;
171 	u32			len;
172 	void			*buf;
173 	void __iomem		*mbase =  musb->mregs;
174 	struct urb		*urb = next_urb(qh);
175 	struct musb_hw_ep	*hw_ep = qh->hw_ep;
176 	unsigned		pipe = urb->pipe;
177 	u8			address = usb_pipedevice(pipe);
178 	int			epnum = hw_ep->epnum;
179 
180 	/* initialize software qh state */
181 	qh->offset = 0;
182 	qh->segsize = 0;
183 
184 	/* gather right source of data */
185 	switch (qh->type) {
186 	case USB_ENDPOINT_XFER_CONTROL:
187 		/* control transfers always start with SETUP */
188 		is_in = 0;
189 		hw_ep->out_qh = qh;
190 		musb->ep0_stage = MUSB_EP0_START;
191 		buf = urb->setup_packet;
192 		len = 8;
193 		break;
194 	case USB_ENDPOINT_XFER_ISOC:
195 		qh->iso_idx = 0;
196 		qh->frame = 0;
197 		buf = urb->transfer_buffer + urb->iso_frame_desc[0].offset;
198 		len = urb->iso_frame_desc[0].length;
199 		break;
200 	default:		/* bulk, interrupt */
201 		buf = urb->transfer_buffer;
202 		len = urb->transfer_buffer_length;
203 	}
204 
205 	DBG(4, "qh %p urb %p dev%d ep%d%s%s, hw_ep %d, %p/%d\n",
206 			qh, urb, address, qh->epnum,
207 			is_in ? "in" : "out",
208 			({char *s; switch (qh->type) {
209 			case USB_ENDPOINT_XFER_CONTROL:	s = ""; break;
210 			case USB_ENDPOINT_XFER_BULK:	s = "-bulk"; break;
211 			case USB_ENDPOINT_XFER_ISOC:	s = "-iso"; break;
212 			default:			s = "-intr"; break;
213 			}; s; }),
214 			epnum, buf, len);
215 
216 	/* Configure endpoint */
217 	if (is_in || hw_ep->is_shared_fifo)
218 		hw_ep->in_qh = qh;
219 	else
220 		hw_ep->out_qh = qh;
221 	musb_ep_program(musb, epnum, urb, !is_in, buf, len);
222 
223 	/* transmit may have more work: start it when it is time */
224 	if (is_in)
225 		return;
226 
227 	/* determine if the time is right for a periodic transfer */
228 	switch (qh->type) {
229 	case USB_ENDPOINT_XFER_ISOC:
230 	case USB_ENDPOINT_XFER_INT:
231 		DBG(3, "check whether there's still time for periodic Tx\n");
232 		qh->iso_idx = 0;
233 		frame = musb_readw(mbase, MUSB_FRAME);
234 		/* FIXME this doesn't implement that scheduling policy ...
235 		 * or handle framecounter wrapping
236 		 */
237 		if ((urb->transfer_flags & URB_ISO_ASAP)
238 				|| (frame >= urb->start_frame)) {
239 			/* REVISIT the SOF irq handler shouldn't duplicate
240 			 * this code; and we don't init urb->start_frame...
241 			 */
242 			qh->frame = 0;
243 			goto start;
244 		} else {
245 			qh->frame = urb->start_frame;
246 			/* enable SOF interrupt so we can count down */
247 			DBG(1, "SOF for %d\n", epnum);
248 #if 1 /* ifndef	CONFIG_ARCH_DAVINCI */
249 			musb_writeb(mbase, MUSB_INTRUSBE, 0xff);
250 #endif
251 		}
252 		break;
253 	default:
254 start:
255 		DBG(4, "Start TX%d %s\n", epnum,
256 			hw_ep->tx_channel ? "dma" : "pio");
257 
258 		if (!hw_ep->tx_channel)
259 			musb_h_tx_start(hw_ep);
260 		else if (is_cppi_enabled() || tusb_dma_omap())
261 			cppi_host_txdma_start(hw_ep);
262 	}
263 }
264 
265 /* caller owns controller lock, irqs are blocked */
266 static void
267 __musb_giveback(struct musb *musb, struct urb *urb, int status)
268 __releases(musb->lock)
269 __acquires(musb->lock)
270 {
271 	DBG(({ int level; switch (urb->status) {
272 				case 0:
273 					level = 4;
274 					break;
275 				/* common/boring faults */
276 				case -EREMOTEIO:
277 				case -ESHUTDOWN:
278 				case -ECONNRESET:
279 				case -EPIPE:
280 					level = 3;
281 					break;
282 				default:
283 					level = 2;
284 					break;
285 				}; level; }),
286 			"complete %p (%d), dev%d ep%d%s, %d/%d\n",
287 			urb, urb->status,
288 			usb_pipedevice(urb->pipe),
289 			usb_pipeendpoint(urb->pipe),
290 			usb_pipein(urb->pipe) ? "in" : "out",
291 			urb->actual_length, urb->transfer_buffer_length
292 			);
293 
294 	spin_unlock(&musb->lock);
295 	usb_hcd_giveback_urb(musb_to_hcd(musb), urb, status);
296 	spin_lock(&musb->lock);
297 }
298 
299 /* for bulk/interrupt endpoints only */
300 static inline void
301 musb_save_toggle(struct musb_hw_ep *ep, int is_in, struct urb *urb)
302 {
303 	struct usb_device	*udev = urb->dev;
304 	u16			csr;
305 	void __iomem		*epio = ep->regs;
306 	struct musb_qh		*qh;
307 
308 	/* FIXME:  the current Mentor DMA code seems to have
309 	 * problems getting toggle correct.
310 	 */
311 
312 	if (is_in || ep->is_shared_fifo)
313 		qh = ep->in_qh;
314 	else
315 		qh = ep->out_qh;
316 
317 	if (!is_in) {
318 		csr = musb_readw(epio, MUSB_TXCSR);
319 		usb_settoggle(udev, qh->epnum, 1,
320 			(csr & MUSB_TXCSR_H_DATATOGGLE)
321 				? 1 : 0);
322 	} else {
323 		csr = musb_readw(epio, MUSB_RXCSR);
324 		usb_settoggle(udev, qh->epnum, 0,
325 			(csr & MUSB_RXCSR_H_DATATOGGLE)
326 				? 1 : 0);
327 	}
328 }
329 
330 /* caller owns controller lock, irqs are blocked */
331 static struct musb_qh *
332 musb_giveback(struct musb_qh *qh, struct urb *urb, int status)
333 {
334 	int			is_in;
335 	struct musb_hw_ep	*ep = qh->hw_ep;
336 	struct musb		*musb = ep->musb;
337 	int			ready = qh->is_ready;
338 
339 	if (ep->is_shared_fifo)
340 		is_in = 1;
341 	else
342 		is_in = usb_pipein(urb->pipe);
343 
344 	/* save toggle eagerly, for paranoia */
345 	switch (qh->type) {
346 	case USB_ENDPOINT_XFER_BULK:
347 	case USB_ENDPOINT_XFER_INT:
348 		musb_save_toggle(ep, is_in, urb);
349 		break;
350 	case USB_ENDPOINT_XFER_ISOC:
351 		if (status == 0 && urb->error_count)
352 			status = -EXDEV;
353 		break;
354 	}
355 
356 	usb_hcd_unlink_urb_from_ep(musb_to_hcd(musb), urb);
357 
358 	qh->is_ready = 0;
359 	__musb_giveback(musb, urb, status);
360 	qh->is_ready = ready;
361 
362 	/* reclaim resources (and bandwidth) ASAP; deschedule it, and
363 	 * invalidate qh as soon as list_empty(&hep->urb_list)
364 	 */
365 	if (list_empty(&qh->hep->urb_list)) {
366 		struct list_head	*head;
367 
368 		if (is_in)
369 			ep->rx_reinit = 1;
370 		else
371 			ep->tx_reinit = 1;
372 
373 		/* clobber old pointers to this qh */
374 		if (is_in || ep->is_shared_fifo)
375 			ep->in_qh = NULL;
376 		else
377 			ep->out_qh = NULL;
378 		qh->hep->hcpriv = NULL;
379 
380 		switch (qh->type) {
381 
382 		case USB_ENDPOINT_XFER_ISOC:
383 		case USB_ENDPOINT_XFER_INT:
384 			/* this is where periodic bandwidth should be
385 			 * de-allocated if it's tracked and allocated;
386 			 * and where we'd update the schedule tree...
387 			 */
388 			musb->periodic[ep->epnum] = NULL;
389 			kfree(qh);
390 			qh = NULL;
391 			break;
392 
393 		case USB_ENDPOINT_XFER_CONTROL:
394 		case USB_ENDPOINT_XFER_BULK:
395 			/* fifo policy for these lists, except that NAKing
396 			 * should rotate a qh to the end (for fairness).
397 			 */
398 			head = qh->ring.prev;
399 			list_del(&qh->ring);
400 			kfree(qh);
401 			qh = first_qh(head);
402 			break;
403 		}
404 	}
405 	return qh;
406 }
407 
408 /*
409  * Advance this hardware endpoint's queue, completing the specified urb and
410  * advancing to either the next urb queued to that qh, or else invalidating
411  * that qh and advancing to the next qh scheduled after the current one.
412  *
413  * Context: caller owns controller lock, irqs are blocked
414  */
415 static void
416 musb_advance_schedule(struct musb *musb, struct urb *urb,
417 		struct musb_hw_ep *hw_ep, int is_in)
418 {
419 	struct musb_qh	*qh;
420 
421 	if (is_in || hw_ep->is_shared_fifo)
422 		qh = hw_ep->in_qh;
423 	else
424 		qh = hw_ep->out_qh;
425 
426 	if (urb->status == -EINPROGRESS)
427 		qh = musb_giveback(qh, urb, 0);
428 	else
429 		qh = musb_giveback(qh, urb, urb->status);
430 
431 	if (qh && qh->is_ready && !list_empty(&qh->hep->urb_list)) {
432 		DBG(4, "... next ep%d %cX urb %p\n",
433 				hw_ep->epnum, is_in ? 'R' : 'T',
434 				next_urb(qh));
435 		musb_start_urb(musb, is_in, qh);
436 	}
437 }
438 
439 static inline u16 musb_h_flush_rxfifo(struct musb_hw_ep *hw_ep, u16 csr)
440 {
441 	/* we don't want fifo to fill itself again;
442 	 * ignore dma (various models),
443 	 * leave toggle alone (may not have been saved yet)
444 	 */
445 	csr |= MUSB_RXCSR_FLUSHFIFO | MUSB_RXCSR_RXPKTRDY;
446 	csr &= ~(MUSB_RXCSR_H_REQPKT
447 		| MUSB_RXCSR_H_AUTOREQ
448 		| MUSB_RXCSR_AUTOCLEAR);
449 
450 	/* write 2x to allow double buffering */
451 	musb_writew(hw_ep->regs, MUSB_RXCSR, csr);
452 	musb_writew(hw_ep->regs, MUSB_RXCSR, csr);
453 
454 	/* flush writebuffer */
455 	return musb_readw(hw_ep->regs, MUSB_RXCSR);
456 }
457 
458 /*
459  * PIO RX for a packet (or part of it).
460  */
461 static bool
462 musb_host_packet_rx(struct musb *musb, struct urb *urb, u8 epnum, u8 iso_err)
463 {
464 	u16			rx_count;
465 	u8			*buf;
466 	u16			csr;
467 	bool			done = false;
468 	u32			length;
469 	int			do_flush = 0;
470 	struct musb_hw_ep	*hw_ep = musb->endpoints + epnum;
471 	void __iomem		*epio = hw_ep->regs;
472 	struct musb_qh		*qh = hw_ep->in_qh;
473 	int			pipe = urb->pipe;
474 	void			*buffer = urb->transfer_buffer;
475 
476 	/* musb_ep_select(mbase, epnum); */
477 	rx_count = musb_readw(epio, MUSB_RXCOUNT);
478 	DBG(3, "RX%d count %d, buffer %p len %d/%d\n", epnum, rx_count,
479 			urb->transfer_buffer, qh->offset,
480 			urb->transfer_buffer_length);
481 
482 	/* unload FIFO */
483 	if (usb_pipeisoc(pipe)) {
484 		int					status = 0;
485 		struct usb_iso_packet_descriptor	*d;
486 
487 		if (iso_err) {
488 			status = -EILSEQ;
489 			urb->error_count++;
490 		}
491 
492 		d = urb->iso_frame_desc + qh->iso_idx;
493 		buf = buffer + d->offset;
494 		length = d->length;
495 		if (rx_count > length) {
496 			if (status == 0) {
497 				status = -EOVERFLOW;
498 				urb->error_count++;
499 			}
500 			DBG(2, "** OVERFLOW %d into %d\n", rx_count, length);
501 			do_flush = 1;
502 		} else
503 			length = rx_count;
504 		urb->actual_length += length;
505 		d->actual_length = length;
506 
507 		d->status = status;
508 
509 		/* see if we are done */
510 		done = (++qh->iso_idx >= urb->number_of_packets);
511 	} else {
512 		/* non-isoch */
513 		buf = buffer + qh->offset;
514 		length = urb->transfer_buffer_length - qh->offset;
515 		if (rx_count > length) {
516 			if (urb->status == -EINPROGRESS)
517 				urb->status = -EOVERFLOW;
518 			DBG(2, "** OVERFLOW %d into %d\n", rx_count, length);
519 			do_flush = 1;
520 		} else
521 			length = rx_count;
522 		urb->actual_length += length;
523 		qh->offset += length;
524 
525 		/* see if we are done */
526 		done = (urb->actual_length == urb->transfer_buffer_length)
527 			|| (rx_count < qh->maxpacket)
528 			|| (urb->status != -EINPROGRESS);
529 		if (done
530 				&& (urb->status == -EINPROGRESS)
531 				&& (urb->transfer_flags & URB_SHORT_NOT_OK)
532 				&& (urb->actual_length
533 					< urb->transfer_buffer_length))
534 			urb->status = -EREMOTEIO;
535 	}
536 
537 	musb_read_fifo(hw_ep, length, buf);
538 
539 	csr = musb_readw(epio, MUSB_RXCSR);
540 	csr |= MUSB_RXCSR_H_WZC_BITS;
541 	if (unlikely(do_flush))
542 		musb_h_flush_rxfifo(hw_ep, csr);
543 	else {
544 		/* REVISIT this assumes AUTOCLEAR is never set */
545 		csr &= ~(MUSB_RXCSR_RXPKTRDY | MUSB_RXCSR_H_REQPKT);
546 		if (!done)
547 			csr |= MUSB_RXCSR_H_REQPKT;
548 		musb_writew(epio, MUSB_RXCSR, csr);
549 	}
550 
551 	return done;
552 }
553 
554 /* we don't always need to reinit a given side of an endpoint...
555  * when we do, use tx/rx reinit routine and then construct a new CSR
556  * to address data toggle, NYET, and DMA or PIO.
557  *
558  * it's possible that driver bugs (especially for DMA) or aborting a
559  * transfer might have left the endpoint busier than it should be.
560  * the busy/not-empty tests are basically paranoia.
561  */
562 static void
563 musb_rx_reinit(struct musb *musb, struct musb_qh *qh, struct musb_hw_ep *ep)
564 {
565 	u16	csr;
566 
567 	/* NOTE:  we know the "rx" fifo reinit never triggers for ep0.
568 	 * That always uses tx_reinit since ep0 repurposes TX register
569 	 * offsets; the initial SETUP packet is also a kind of OUT.
570 	 */
571 
572 	/* if programmed for Tx, put it in RX mode */
573 	if (ep->is_shared_fifo) {
574 		csr = musb_readw(ep->regs, MUSB_TXCSR);
575 		if (csr & MUSB_TXCSR_MODE) {
576 			musb_h_tx_flush_fifo(ep);
577 			musb_writew(ep->regs, MUSB_TXCSR,
578 					MUSB_TXCSR_FRCDATATOG);
579 		}
580 		/* clear mode (and everything else) to enable Rx */
581 		musb_writew(ep->regs, MUSB_TXCSR, 0);
582 
583 	/* scrub all previous state, clearing toggle */
584 	} else {
585 		csr = musb_readw(ep->regs, MUSB_RXCSR);
586 		if (csr & MUSB_RXCSR_RXPKTRDY)
587 			WARNING("rx%d, packet/%d ready?\n", ep->epnum,
588 				musb_readw(ep->regs, MUSB_RXCOUNT));
589 
590 		musb_h_flush_rxfifo(ep, MUSB_RXCSR_CLRDATATOG);
591 	}
592 
593 	/* target addr and (for multipoint) hub addr/port */
594 	if (musb->is_multipoint) {
595 		musb_writeb(ep->target_regs, MUSB_RXFUNCADDR,
596 			qh->addr_reg);
597 		musb_writeb(ep->target_regs, MUSB_RXHUBADDR,
598 			qh->h_addr_reg);
599 		musb_writeb(ep->target_regs, MUSB_RXHUBPORT,
600 			qh->h_port_reg);
601 	} else
602 		musb_writeb(musb->mregs, MUSB_FADDR, qh->addr_reg);
603 
604 	/* protocol/endpoint, interval/NAKlimit, i/o size */
605 	musb_writeb(ep->regs, MUSB_RXTYPE, qh->type_reg);
606 	musb_writeb(ep->regs, MUSB_RXINTERVAL, qh->intv_reg);
607 	/* NOTE: bulk combining rewrites high bits of maxpacket */
608 	musb_writew(ep->regs, MUSB_RXMAXP, qh->maxpacket);
609 
610 	ep->rx_reinit = 0;
611 }
612 
613 
614 /*
615  * Program an HDRC endpoint as per the given URB
616  * Context: irqs blocked, controller lock held
617  */
618 static void musb_ep_program(struct musb *musb, u8 epnum,
619 			struct urb *urb, unsigned int is_out,
620 			u8 *buf, u32 len)
621 {
622 	struct dma_controller	*dma_controller;
623 	struct dma_channel	*dma_channel;
624 	u8			dma_ok;
625 	void __iomem		*mbase = musb->mregs;
626 	struct musb_hw_ep	*hw_ep = musb->endpoints + epnum;
627 	void __iomem		*epio = hw_ep->regs;
628 	struct musb_qh		*qh;
629 	u16			packet_sz;
630 
631 	if (!is_out || hw_ep->is_shared_fifo)
632 		qh = hw_ep->in_qh;
633 	else
634 		qh = hw_ep->out_qh;
635 
636 	packet_sz = qh->maxpacket;
637 
638 	DBG(3, "%s hw%d urb %p spd%d dev%d ep%d%s "
639 				"h_addr%02x h_port%02x bytes %d\n",
640 			is_out ? "-->" : "<--",
641 			epnum, urb, urb->dev->speed,
642 			qh->addr_reg, qh->epnum, is_out ? "out" : "in",
643 			qh->h_addr_reg, qh->h_port_reg,
644 			len);
645 
646 	musb_ep_select(mbase, epnum);
647 
648 	/* candidate for DMA? */
649 	dma_controller = musb->dma_controller;
650 	if (is_dma_capable() && epnum && dma_controller) {
651 		dma_channel = is_out ? hw_ep->tx_channel : hw_ep->rx_channel;
652 		if (!dma_channel) {
653 			dma_channel = dma_controller->channel_alloc(
654 					dma_controller, hw_ep, is_out);
655 			if (is_out)
656 				hw_ep->tx_channel = dma_channel;
657 			else
658 				hw_ep->rx_channel = dma_channel;
659 		}
660 	} else
661 		dma_channel = NULL;
662 
663 	/* make sure we clear DMAEnab, autoSet bits from previous run */
664 
665 	/* OUT/transmit/EP0 or IN/receive? */
666 	if (is_out) {
667 		u16	csr;
668 		u16	int_txe;
669 		u16	load_count;
670 
671 		csr = musb_readw(epio, MUSB_TXCSR);
672 
673 		/* disable interrupt in case we flush */
674 		int_txe = musb_readw(mbase, MUSB_INTRTXE);
675 		musb_writew(mbase, MUSB_INTRTXE, int_txe & ~(1 << epnum));
676 
677 		/* general endpoint setup */
678 		if (epnum) {
679 			/* ASSERT:  TXCSR_DMAENAB was already cleared */
680 
681 			/* flush all old state, set default */
682 			musb_h_tx_flush_fifo(hw_ep);
683 			csr &= ~(MUSB_TXCSR_H_NAKTIMEOUT
684 					| MUSB_TXCSR_DMAMODE
685 					| MUSB_TXCSR_FRCDATATOG
686 					| MUSB_TXCSR_H_RXSTALL
687 					| MUSB_TXCSR_H_ERROR
688 					| MUSB_TXCSR_TXPKTRDY
689 					);
690 			csr |= MUSB_TXCSR_MODE;
691 
692 			if (usb_gettoggle(urb->dev,
693 					qh->epnum, 1))
694 				csr |= MUSB_TXCSR_H_WR_DATATOGGLE
695 					| MUSB_TXCSR_H_DATATOGGLE;
696 			else
697 				csr |= MUSB_TXCSR_CLRDATATOG;
698 
699 			/* twice in case of double packet buffering */
700 			musb_writew(epio, MUSB_TXCSR, csr);
701 			/* REVISIT may need to clear FLUSHFIFO ... */
702 			musb_writew(epio, MUSB_TXCSR, csr);
703 			csr = musb_readw(epio, MUSB_TXCSR);
704 		} else {
705 			/* endpoint 0: just flush */
706 			musb_writew(epio, MUSB_CSR0,
707 				csr | MUSB_CSR0_FLUSHFIFO);
708 			musb_writew(epio, MUSB_CSR0,
709 				csr | MUSB_CSR0_FLUSHFIFO);
710 		}
711 
712 		/* target addr and (for multipoint) hub addr/port */
713 		if (musb->is_multipoint) {
714 			musb_writeb(mbase,
715 				MUSB_BUSCTL_OFFSET(epnum, MUSB_TXFUNCADDR),
716 				qh->addr_reg);
717 			musb_writeb(mbase,
718 				MUSB_BUSCTL_OFFSET(epnum, MUSB_TXHUBADDR),
719 				qh->h_addr_reg);
720 			musb_writeb(mbase,
721 				MUSB_BUSCTL_OFFSET(epnum, MUSB_TXHUBPORT),
722 				qh->h_port_reg);
723 /* FIXME if !epnum, do the same for RX ... */
724 		} else
725 			musb_writeb(mbase, MUSB_FADDR, qh->addr_reg);
726 
727 		/* protocol/endpoint/interval/NAKlimit */
728 		if (epnum) {
729 			musb_writeb(epio, MUSB_TXTYPE, qh->type_reg);
730 			if (can_bulk_split(musb, qh->type))
731 				musb_writew(epio, MUSB_TXMAXP,
732 					packet_sz
733 					| ((hw_ep->max_packet_sz_tx /
734 						packet_sz) - 1) << 11);
735 			else
736 				musb_writew(epio, MUSB_TXMAXP,
737 					packet_sz);
738 			musb_writeb(epio, MUSB_TXINTERVAL, qh->intv_reg);
739 		} else {
740 			musb_writeb(epio, MUSB_NAKLIMIT0, qh->intv_reg);
741 			if (musb->is_multipoint)
742 				musb_writeb(epio, MUSB_TYPE0,
743 						qh->type_reg);
744 		}
745 
746 		if (can_bulk_split(musb, qh->type))
747 			load_count = min((u32) hw_ep->max_packet_sz_tx,
748 						len);
749 		else
750 			load_count = min((u32) packet_sz, len);
751 
752 #ifdef CONFIG_USB_INVENTRA_DMA
753 		if (dma_channel) {
754 
755 			/* clear previous state */
756 			csr = musb_readw(epio, MUSB_TXCSR);
757 			csr &= ~(MUSB_TXCSR_AUTOSET
758 				| MUSB_TXCSR_DMAMODE
759 				| MUSB_TXCSR_DMAENAB);
760 			csr |= MUSB_TXCSR_MODE;
761 			musb_writew(epio, MUSB_TXCSR,
762 				csr | MUSB_TXCSR_MODE);
763 
764 			qh->segsize = min(len, dma_channel->max_len);
765 
766 			if (qh->segsize <= packet_sz)
767 				dma_channel->desired_mode = 0;
768 			else
769 				dma_channel->desired_mode = 1;
770 
771 
772 			if (dma_channel->desired_mode == 0) {
773 				csr &= ~(MUSB_TXCSR_AUTOSET
774 					| MUSB_TXCSR_DMAMODE);
775 				csr |= (MUSB_TXCSR_DMAENAB);
776 					/* against programming guide */
777 			} else
778 				csr |= (MUSB_TXCSR_AUTOSET
779 					| MUSB_TXCSR_DMAENAB
780 					| MUSB_TXCSR_DMAMODE);
781 
782 			musb_writew(epio, MUSB_TXCSR, csr);
783 
784 			dma_ok = dma_controller->channel_program(
785 					dma_channel, packet_sz,
786 					dma_channel->desired_mode,
787 					urb->transfer_dma,
788 					qh->segsize);
789 			if (dma_ok) {
790 				load_count = 0;
791 			} else {
792 				dma_controller->channel_release(dma_channel);
793 				if (is_out)
794 					hw_ep->tx_channel = NULL;
795 				else
796 					hw_ep->rx_channel = NULL;
797 				dma_channel = NULL;
798 			}
799 		}
800 #endif
801 
802 		/* candidate for DMA */
803 		if ((is_cppi_enabled() || tusb_dma_omap()) && dma_channel) {
804 
805 			/* program endpoint CSRs first, then setup DMA.
806 			 * assume CPPI setup succeeds.
807 			 * defer enabling dma.
808 			 */
809 			csr = musb_readw(epio, MUSB_TXCSR);
810 			csr &= ~(MUSB_TXCSR_AUTOSET
811 					| MUSB_TXCSR_DMAMODE
812 					| MUSB_TXCSR_DMAENAB);
813 			csr |= MUSB_TXCSR_MODE;
814 			musb_writew(epio, MUSB_TXCSR,
815 				csr | MUSB_TXCSR_MODE);
816 
817 			dma_channel->actual_len = 0L;
818 			qh->segsize = len;
819 
820 			/* TX uses "rndis" mode automatically, but needs help
821 			 * to identify the zero-length-final-packet case.
822 			 */
823 			dma_ok = dma_controller->channel_program(
824 					dma_channel, packet_sz,
825 					(urb->transfer_flags
826 							& URB_ZERO_PACKET)
827 						== URB_ZERO_PACKET,
828 					urb->transfer_dma,
829 					qh->segsize);
830 			if (dma_ok) {
831 				load_count = 0;
832 			} else {
833 				dma_controller->channel_release(dma_channel);
834 				hw_ep->tx_channel = NULL;
835 				dma_channel = NULL;
836 
837 				/* REVISIT there's an error path here that
838 				 * needs handling:  can't do dma, but
839 				 * there's no pio buffer address...
840 				 */
841 			}
842 		}
843 
844 		if (load_count) {
845 			/* ASSERT:  TXCSR_DMAENAB was already cleared */
846 
847 			/* PIO to load FIFO */
848 			qh->segsize = load_count;
849 			musb_write_fifo(hw_ep, load_count, buf);
850 			csr = musb_readw(epio, MUSB_TXCSR);
851 			csr &= ~(MUSB_TXCSR_DMAENAB
852 				| MUSB_TXCSR_DMAMODE
853 				| MUSB_TXCSR_AUTOSET);
854 			/* write CSR */
855 			csr |= MUSB_TXCSR_MODE;
856 
857 			if (epnum)
858 				musb_writew(epio, MUSB_TXCSR, csr);
859 		}
860 
861 		/* re-enable interrupt */
862 		musb_writew(mbase, MUSB_INTRTXE, int_txe);
863 
864 	/* IN/receive */
865 	} else {
866 		u16	csr;
867 
868 		if (hw_ep->rx_reinit) {
869 			musb_rx_reinit(musb, qh, hw_ep);
870 
871 			/* init new state: toggle and NYET, maybe DMA later */
872 			if (usb_gettoggle(urb->dev, qh->epnum, 0))
873 				csr = MUSB_RXCSR_H_WR_DATATOGGLE
874 					| MUSB_RXCSR_H_DATATOGGLE;
875 			else
876 				csr = 0;
877 			if (qh->type == USB_ENDPOINT_XFER_INT)
878 				csr |= MUSB_RXCSR_DISNYET;
879 
880 		} else {
881 			csr = musb_readw(hw_ep->regs, MUSB_RXCSR);
882 
883 			if (csr & (MUSB_RXCSR_RXPKTRDY
884 					| MUSB_RXCSR_DMAENAB
885 					| MUSB_RXCSR_H_REQPKT))
886 				ERR("broken !rx_reinit, ep%d csr %04x\n",
887 						hw_ep->epnum, csr);
888 
889 			/* scrub any stale state, leaving toggle alone */
890 			csr &= MUSB_RXCSR_DISNYET;
891 		}
892 
893 		/* kick things off */
894 
895 		if ((is_cppi_enabled() || tusb_dma_omap()) && dma_channel) {
896 			/* candidate for DMA */
897 			if (dma_channel) {
898 				dma_channel->actual_len = 0L;
899 				qh->segsize = len;
900 
901 				/* AUTOREQ is in a DMA register */
902 				musb_writew(hw_ep->regs, MUSB_RXCSR, csr);
903 				csr = musb_readw(hw_ep->regs,
904 						MUSB_RXCSR);
905 
906 				/* unless caller treats short rx transfers as
907 				 * errors, we dare not queue multiple transfers.
908 				 */
909 				dma_ok = dma_controller->channel_program(
910 						dma_channel, packet_sz,
911 						!(urb->transfer_flags
912 							& URB_SHORT_NOT_OK),
913 						urb->transfer_dma,
914 						qh->segsize);
915 				if (!dma_ok) {
916 					dma_controller->channel_release(
917 							dma_channel);
918 					hw_ep->rx_channel = NULL;
919 					dma_channel = NULL;
920 				} else
921 					csr |= MUSB_RXCSR_DMAENAB;
922 			}
923 		}
924 
925 		csr |= MUSB_RXCSR_H_REQPKT;
926 		DBG(7, "RXCSR%d := %04x\n", epnum, csr);
927 		musb_writew(hw_ep->regs, MUSB_RXCSR, csr);
928 		csr = musb_readw(hw_ep->regs, MUSB_RXCSR);
929 	}
930 }
931 
932 
933 /*
934  * Service the default endpoint (ep0) as host.
935  * Return true until it's time to start the status stage.
936  */
937 static bool musb_h_ep0_continue(struct musb *musb, u16 len, struct urb *urb)
938 {
939 	bool			 more = false;
940 	u8			*fifo_dest = NULL;
941 	u16			fifo_count = 0;
942 	struct musb_hw_ep	*hw_ep = musb->control_ep;
943 	struct musb_qh		*qh = hw_ep->in_qh;
944 	struct usb_ctrlrequest	*request;
945 
946 	switch (musb->ep0_stage) {
947 	case MUSB_EP0_IN:
948 		fifo_dest = urb->transfer_buffer + urb->actual_length;
949 		fifo_count = min(len, ((u16) (urb->transfer_buffer_length
950 					- urb->actual_length)));
951 		if (fifo_count < len)
952 			urb->status = -EOVERFLOW;
953 
954 		musb_read_fifo(hw_ep, fifo_count, fifo_dest);
955 
956 		urb->actual_length += fifo_count;
957 		if (len < qh->maxpacket) {
958 			/* always terminate on short read; it's
959 			 * rarely reported as an error.
960 			 */
961 		} else if (urb->actual_length <
962 				urb->transfer_buffer_length)
963 			more = true;
964 		break;
965 	case MUSB_EP0_START:
966 		request = (struct usb_ctrlrequest *) urb->setup_packet;
967 
968 		if (!request->wLength) {
969 			DBG(4, "start no-DATA\n");
970 			break;
971 		} else if (request->bRequestType & USB_DIR_IN) {
972 			DBG(4, "start IN-DATA\n");
973 			musb->ep0_stage = MUSB_EP0_IN;
974 			more = true;
975 			break;
976 		} else {
977 			DBG(4, "start OUT-DATA\n");
978 			musb->ep0_stage = MUSB_EP0_OUT;
979 			more = true;
980 		}
981 		/* FALLTHROUGH */
982 	case MUSB_EP0_OUT:
983 		fifo_count = min(qh->maxpacket, ((u16)
984 				(urb->transfer_buffer_length
985 				- urb->actual_length)));
986 
987 		if (fifo_count) {
988 			fifo_dest = (u8 *) (urb->transfer_buffer
989 					+ urb->actual_length);
990 			DBG(3, "Sending %d bytes to %p\n",
991 					fifo_count, fifo_dest);
992 			musb_write_fifo(hw_ep, fifo_count, fifo_dest);
993 
994 			urb->actual_length += fifo_count;
995 			more = true;
996 		}
997 		break;
998 	default:
999 		ERR("bogus ep0 stage %d\n", musb->ep0_stage);
1000 		break;
1001 	}
1002 
1003 	return more;
1004 }
1005 
1006 /*
1007  * Handle default endpoint interrupt as host. Only called in IRQ time
1008  * from the LinuxIsr() interrupt service routine.
1009  *
1010  * called with controller irqlocked
1011  */
1012 irqreturn_t musb_h_ep0_irq(struct musb *musb)
1013 {
1014 	struct urb		*urb;
1015 	u16			csr, len;
1016 	int			status = 0;
1017 	void __iomem		*mbase = musb->mregs;
1018 	struct musb_hw_ep	*hw_ep = musb->control_ep;
1019 	void __iomem		*epio = hw_ep->regs;
1020 	struct musb_qh		*qh = hw_ep->in_qh;
1021 	bool			complete = false;
1022 	irqreturn_t		retval = IRQ_NONE;
1023 
1024 	/* ep0 only has one queue, "in" */
1025 	urb = next_urb(qh);
1026 
1027 	musb_ep_select(mbase, 0);
1028 	csr = musb_readw(epio, MUSB_CSR0);
1029 	len = (csr & MUSB_CSR0_RXPKTRDY)
1030 			? musb_readb(epio, MUSB_COUNT0)
1031 			: 0;
1032 
1033 	DBG(4, "<== csr0 %04x, qh %p, count %d, urb %p, stage %d\n",
1034 		csr, qh, len, urb, musb->ep0_stage);
1035 
1036 	/* if we just did status stage, we are done */
1037 	if (MUSB_EP0_STATUS == musb->ep0_stage) {
1038 		retval = IRQ_HANDLED;
1039 		complete = true;
1040 	}
1041 
1042 	/* prepare status */
1043 	if (csr & MUSB_CSR0_H_RXSTALL) {
1044 		DBG(6, "STALLING ENDPOINT\n");
1045 		status = -EPIPE;
1046 
1047 	} else if (csr & MUSB_CSR0_H_ERROR) {
1048 		DBG(2, "no response, csr0 %04x\n", csr);
1049 		status = -EPROTO;
1050 
1051 	} else if (csr & MUSB_CSR0_H_NAKTIMEOUT) {
1052 		DBG(2, "control NAK timeout\n");
1053 
1054 		/* NOTE:  this code path would be a good place to PAUSE a
1055 		 * control transfer, if another one is queued, so that
1056 		 * ep0 is more likely to stay busy.
1057 		 *
1058 		 * if (qh->ring.next != &musb->control), then
1059 		 * we have a candidate... NAKing is *NOT* an error
1060 		 */
1061 		musb_writew(epio, MUSB_CSR0, 0);
1062 		retval = IRQ_HANDLED;
1063 	}
1064 
1065 	if (status) {
1066 		DBG(6, "aborting\n");
1067 		retval = IRQ_HANDLED;
1068 		if (urb)
1069 			urb->status = status;
1070 		complete = true;
1071 
1072 		/* use the proper sequence to abort the transfer */
1073 		if (csr & MUSB_CSR0_H_REQPKT) {
1074 			csr &= ~MUSB_CSR0_H_REQPKT;
1075 			musb_writew(epio, MUSB_CSR0, csr);
1076 			csr &= ~MUSB_CSR0_H_NAKTIMEOUT;
1077 			musb_writew(epio, MUSB_CSR0, csr);
1078 		} else {
1079 			csr |= MUSB_CSR0_FLUSHFIFO;
1080 			musb_writew(epio, MUSB_CSR0, csr);
1081 			musb_writew(epio, MUSB_CSR0, csr);
1082 			csr &= ~MUSB_CSR0_H_NAKTIMEOUT;
1083 			musb_writew(epio, MUSB_CSR0, csr);
1084 		}
1085 
1086 		musb_writeb(epio, MUSB_NAKLIMIT0, 0);
1087 
1088 		/* clear it */
1089 		musb_writew(epio, MUSB_CSR0, 0);
1090 	}
1091 
1092 	if (unlikely(!urb)) {
1093 		/* stop endpoint since we have no place for its data, this
1094 		 * SHOULD NEVER HAPPEN! */
1095 		ERR("no URB for end 0\n");
1096 
1097 		musb_writew(epio, MUSB_CSR0, MUSB_CSR0_FLUSHFIFO);
1098 		musb_writew(epio, MUSB_CSR0, MUSB_CSR0_FLUSHFIFO);
1099 		musb_writew(epio, MUSB_CSR0, 0);
1100 
1101 		goto done;
1102 	}
1103 
1104 	if (!complete) {
1105 		/* call common logic and prepare response */
1106 		if (musb_h_ep0_continue(musb, len, urb)) {
1107 			/* more packets required */
1108 			csr = (MUSB_EP0_IN == musb->ep0_stage)
1109 				?  MUSB_CSR0_H_REQPKT : MUSB_CSR0_TXPKTRDY;
1110 		} else {
1111 			/* data transfer complete; perform status phase */
1112 			if (usb_pipeout(urb->pipe)
1113 					|| !urb->transfer_buffer_length)
1114 				csr = MUSB_CSR0_H_STATUSPKT
1115 					| MUSB_CSR0_H_REQPKT;
1116 			else
1117 				csr = MUSB_CSR0_H_STATUSPKT
1118 					| MUSB_CSR0_TXPKTRDY;
1119 
1120 			/* flag status stage */
1121 			musb->ep0_stage = MUSB_EP0_STATUS;
1122 
1123 			DBG(5, "ep0 STATUS, csr %04x\n", csr);
1124 
1125 		}
1126 		musb_writew(epio, MUSB_CSR0, csr);
1127 		retval = IRQ_HANDLED;
1128 	} else
1129 		musb->ep0_stage = MUSB_EP0_IDLE;
1130 
1131 	/* call completion handler if done */
1132 	if (complete)
1133 		musb_advance_schedule(musb, urb, hw_ep, 1);
1134 done:
1135 	return retval;
1136 }
1137 
1138 
1139 #ifdef CONFIG_USB_INVENTRA_DMA
1140 
1141 /* Host side TX (OUT) using Mentor DMA works as follows:
1142 	submit_urb ->
1143 		- if queue was empty, Program Endpoint
1144 		- ... which starts DMA to fifo in mode 1 or 0
1145 
1146 	DMA Isr (transfer complete) -> TxAvail()
1147 		- Stop DMA (~DmaEnab)	(<--- Alert ... currently happens
1148 					only in musb_cleanup_urb)
1149 		- TxPktRdy has to be set in mode 0 or for
1150 			short packets in mode 1.
1151 */
1152 
1153 #endif
1154 
1155 /* Service a Tx-Available or dma completion irq for the endpoint */
1156 void musb_host_tx(struct musb *musb, u8 epnum)
1157 {
1158 	int			pipe;
1159 	bool			done = false;
1160 	u16			tx_csr;
1161 	size_t			wLength = 0;
1162 	u8			*buf = NULL;
1163 	struct urb		*urb;
1164 	struct musb_hw_ep	*hw_ep = musb->endpoints + epnum;
1165 	void __iomem		*epio = hw_ep->regs;
1166 	struct musb_qh		*qh = hw_ep->out_qh;
1167 	u32			status = 0;
1168 	void __iomem		*mbase = musb->mregs;
1169 	struct dma_channel	*dma;
1170 
1171 	urb = next_urb(qh);
1172 
1173 	musb_ep_select(mbase, epnum);
1174 	tx_csr = musb_readw(epio, MUSB_TXCSR);
1175 
1176 	/* with CPPI, DMA sometimes triggers "extra" irqs */
1177 	if (!urb) {
1178 		DBG(4, "extra TX%d ready, csr %04x\n", epnum, tx_csr);
1179 		goto finish;
1180 	}
1181 
1182 	pipe = urb->pipe;
1183 	dma = is_dma_capable() ? hw_ep->tx_channel : NULL;
1184 	DBG(4, "OUT/TX%d end, csr %04x%s\n", epnum, tx_csr,
1185 			dma ? ", dma" : "");
1186 
1187 	/* check for errors */
1188 	if (tx_csr & MUSB_TXCSR_H_RXSTALL) {
1189 		/* dma was disabled, fifo flushed */
1190 		DBG(3, "TX end %d stall\n", epnum);
1191 
1192 		/* stall; record URB status */
1193 		status = -EPIPE;
1194 
1195 	} else if (tx_csr & MUSB_TXCSR_H_ERROR) {
1196 		/* (NON-ISO) dma was disabled, fifo flushed */
1197 		DBG(3, "TX 3strikes on ep=%d\n", epnum);
1198 
1199 		status = -ETIMEDOUT;
1200 
1201 	} else if (tx_csr & MUSB_TXCSR_H_NAKTIMEOUT) {
1202 		DBG(6, "TX end=%d device not responding\n", epnum);
1203 
1204 		/* NOTE:  this code path would be a good place to PAUSE a
1205 		 * transfer, if there's some other (nonperiodic) tx urb
1206 		 * that could use this fifo.  (dma complicates it...)
1207 		 *
1208 		 * if (bulk && qh->ring.next != &musb->out_bulk), then
1209 		 * we have a candidate... NAKing is *NOT* an error
1210 		 */
1211 		musb_ep_select(mbase, epnum);
1212 		musb_writew(epio, MUSB_TXCSR,
1213 				MUSB_TXCSR_H_WZC_BITS
1214 				| MUSB_TXCSR_TXPKTRDY);
1215 		goto finish;
1216 	}
1217 
1218 	if (status) {
1219 		if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1220 			dma->status = MUSB_DMA_STATUS_CORE_ABORT;
1221 			(void) musb->dma_controller->channel_abort(dma);
1222 		}
1223 
1224 		/* do the proper sequence to abort the transfer in the
1225 		 * usb core; the dma engine should already be stopped.
1226 		 */
1227 		musb_h_tx_flush_fifo(hw_ep);
1228 		tx_csr &= ~(MUSB_TXCSR_AUTOSET
1229 				| MUSB_TXCSR_DMAENAB
1230 				| MUSB_TXCSR_H_ERROR
1231 				| MUSB_TXCSR_H_RXSTALL
1232 				| MUSB_TXCSR_H_NAKTIMEOUT
1233 				);
1234 
1235 		musb_ep_select(mbase, epnum);
1236 		musb_writew(epio, MUSB_TXCSR, tx_csr);
1237 		/* REVISIT may need to clear FLUSHFIFO ... */
1238 		musb_writew(epio, MUSB_TXCSR, tx_csr);
1239 		musb_writeb(epio, MUSB_TXINTERVAL, 0);
1240 
1241 		done = true;
1242 	}
1243 
1244 	/* second cppi case */
1245 	if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1246 		DBG(4, "extra TX%d ready, csr %04x\n", epnum, tx_csr);
1247 		goto finish;
1248 
1249 	}
1250 
1251 	/* REVISIT this looks wrong... */
1252 	if (!status || dma || usb_pipeisoc(pipe)) {
1253 		if (dma)
1254 			wLength = dma->actual_len;
1255 		else
1256 			wLength = qh->segsize;
1257 		qh->offset += wLength;
1258 
1259 		if (usb_pipeisoc(pipe)) {
1260 			struct usb_iso_packet_descriptor	*d;
1261 
1262 			d = urb->iso_frame_desc + qh->iso_idx;
1263 			d->actual_length = qh->segsize;
1264 			if (++qh->iso_idx >= urb->number_of_packets) {
1265 				done = true;
1266 			} else {
1267 				d++;
1268 				buf = urb->transfer_buffer + d->offset;
1269 				wLength = d->length;
1270 			}
1271 		} else if (dma) {
1272 			done = true;
1273 		} else {
1274 			/* see if we need to send more data, or ZLP */
1275 			if (qh->segsize < qh->maxpacket)
1276 				done = true;
1277 			else if (qh->offset == urb->transfer_buffer_length
1278 					&& !(urb->transfer_flags
1279 						& URB_ZERO_PACKET))
1280 				done = true;
1281 			if (!done) {
1282 				buf = urb->transfer_buffer
1283 						+ qh->offset;
1284 				wLength = urb->transfer_buffer_length
1285 						- qh->offset;
1286 			}
1287 		}
1288 	}
1289 
1290 	/* urb->status != -EINPROGRESS means request has been faulted,
1291 	 * so we must abort this transfer after cleanup
1292 	 */
1293 	if (urb->status != -EINPROGRESS) {
1294 		done = true;
1295 		if (status == 0)
1296 			status = urb->status;
1297 	}
1298 
1299 	if (done) {
1300 		/* set status */
1301 		urb->status = status;
1302 		urb->actual_length = qh->offset;
1303 		musb_advance_schedule(musb, urb, hw_ep, USB_DIR_OUT);
1304 
1305 	} else if (!(tx_csr & MUSB_TXCSR_DMAENAB)) {
1306 		/* WARN_ON(!buf); */
1307 
1308 		/* REVISIT:  some docs say that when hw_ep->tx_double_buffered,
1309 		 * (and presumably, fifo is not half-full) we should write TWO
1310 		 * packets before updating TXCSR ... other docs disagree ...
1311 		 */
1312 		/* PIO:  start next packet in this URB */
1313 		wLength = min(qh->maxpacket, (u16) wLength);
1314 		musb_write_fifo(hw_ep, wLength, buf);
1315 		qh->segsize = wLength;
1316 
1317 		musb_ep_select(mbase, epnum);
1318 		musb_writew(epio, MUSB_TXCSR,
1319 				MUSB_TXCSR_H_WZC_BITS | MUSB_TXCSR_TXPKTRDY);
1320 	} else
1321 		DBG(1, "not complete, but dma enabled?\n");
1322 
1323 finish:
1324 	return;
1325 }
1326 
1327 
1328 #ifdef CONFIG_USB_INVENTRA_DMA
1329 
1330 /* Host side RX (IN) using Mentor DMA works as follows:
1331 	submit_urb ->
1332 		- if queue was empty, ProgramEndpoint
1333 		- first IN token is sent out (by setting ReqPkt)
1334 	LinuxIsr -> RxReady()
1335 	/\	=> first packet is received
1336 	|	- Set in mode 0 (DmaEnab, ~ReqPkt)
1337 	|		-> DMA Isr (transfer complete) -> RxReady()
1338 	|		    - Ack receive (~RxPktRdy), turn off DMA (~DmaEnab)
1339 	|		    - if urb not complete, send next IN token (ReqPkt)
1340 	|			   |		else complete urb.
1341 	|			   |
1342 	---------------------------
1343  *
1344  * Nuances of mode 1:
1345  *	For short packets, no ack (+RxPktRdy) is sent automatically
1346  *	(even if AutoClear is ON)
1347  *	For full packets, ack (~RxPktRdy) and next IN token (+ReqPkt) is sent
1348  *	automatically => major problem, as collecting the next packet becomes
1349  *	difficult. Hence mode 1 is not used.
1350  *
1351  * REVISIT
1352  *	All we care about at this driver level is that
1353  *       (a) all URBs terminate with REQPKT cleared and fifo(s) empty;
1354  *       (b) termination conditions are: short RX, or buffer full;
1355  *       (c) fault modes include
1356  *           - iff URB_SHORT_NOT_OK, short RX status is -EREMOTEIO.
1357  *             (and that endpoint's dma queue stops immediately)
1358  *           - overflow (full, PLUS more bytes in the terminal packet)
1359  *
1360  *	So for example, usb-storage sets URB_SHORT_NOT_OK, and would
1361  *	thus be a great candidate for using mode 1 ... for all but the
1362  *	last packet of one URB's transfer.
1363  */
1364 
1365 #endif
1366 
1367 /*
1368  * Service an RX interrupt for the given IN endpoint; docs cover bulk, iso,
1369  * and high-bandwidth IN transfer cases.
1370  */
1371 void musb_host_rx(struct musb *musb, u8 epnum)
1372 {
1373 	struct urb		*urb;
1374 	struct musb_hw_ep	*hw_ep = musb->endpoints + epnum;
1375 	void __iomem		*epio = hw_ep->regs;
1376 	struct musb_qh		*qh = hw_ep->in_qh;
1377 	size_t			xfer_len;
1378 	void __iomem		*mbase = musb->mregs;
1379 	int			pipe;
1380 	u16			rx_csr, val;
1381 	bool			iso_err = false;
1382 	bool			done = false;
1383 	u32			status;
1384 	struct dma_channel	*dma;
1385 
1386 	musb_ep_select(mbase, epnum);
1387 
1388 	urb = next_urb(qh);
1389 	dma = is_dma_capable() ? hw_ep->rx_channel : NULL;
1390 	status = 0;
1391 	xfer_len = 0;
1392 
1393 	rx_csr = musb_readw(epio, MUSB_RXCSR);
1394 	val = rx_csr;
1395 
1396 	if (unlikely(!urb)) {
1397 		/* REVISIT -- THIS SHOULD NEVER HAPPEN ... but, at least
1398 		 * usbtest #11 (unlinks) triggers it regularly, sometimes
1399 		 * with fifo full.  (Only with DMA??)
1400 		 */
1401 		DBG(3, "BOGUS RX%d ready, csr %04x, count %d\n", epnum, val,
1402 			musb_readw(epio, MUSB_RXCOUNT));
1403 		musb_h_flush_rxfifo(hw_ep, MUSB_RXCSR_CLRDATATOG);
1404 		return;
1405 	}
1406 
1407 	pipe = urb->pipe;
1408 
1409 	DBG(5, "<== hw %d rxcsr %04x, urb actual %d (+dma %zu)\n",
1410 		epnum, rx_csr, urb->actual_length,
1411 		dma ? dma->actual_len : 0);
1412 
1413 	/* check for errors, concurrent stall & unlink is not really
1414 	 * handled yet! */
1415 	if (rx_csr & MUSB_RXCSR_H_RXSTALL) {
1416 		DBG(3, "RX end %d STALL\n", epnum);
1417 
1418 		/* stall; record URB status */
1419 		status = -EPIPE;
1420 
1421 	} else if (rx_csr & MUSB_RXCSR_H_ERROR) {
1422 		DBG(3, "end %d RX proto error\n", epnum);
1423 
1424 		status = -EPROTO;
1425 		musb_writeb(epio, MUSB_RXINTERVAL, 0);
1426 
1427 	} else if (rx_csr & MUSB_RXCSR_DATAERROR) {
1428 
1429 		if (USB_ENDPOINT_XFER_ISOC != qh->type) {
1430 			/* NOTE this code path would be a good place to PAUSE a
1431 			 * transfer, if there's some other (nonperiodic) rx urb
1432 			 * that could use this fifo.  (dma complicates it...)
1433 			 *
1434 			 * if (bulk && qh->ring.next != &musb->in_bulk), then
1435 			 * we have a candidate... NAKing is *NOT* an error
1436 			 */
1437 			DBG(6, "RX end %d NAK timeout\n", epnum);
1438 			musb_ep_select(mbase, epnum);
1439 			musb_writew(epio, MUSB_RXCSR,
1440 					MUSB_RXCSR_H_WZC_BITS
1441 					| MUSB_RXCSR_H_REQPKT);
1442 
1443 			goto finish;
1444 		} else {
1445 			DBG(4, "RX end %d ISO data error\n", epnum);
1446 			/* packet error reported later */
1447 			iso_err = true;
1448 		}
1449 	}
1450 
1451 	/* faults abort the transfer */
1452 	if (status) {
1453 		/* clean up dma and collect transfer count */
1454 		if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1455 			dma->status = MUSB_DMA_STATUS_CORE_ABORT;
1456 			(void) musb->dma_controller->channel_abort(dma);
1457 			xfer_len = dma->actual_len;
1458 		}
1459 		musb_h_flush_rxfifo(hw_ep, MUSB_RXCSR_CLRDATATOG);
1460 		musb_writeb(epio, MUSB_RXINTERVAL, 0);
1461 		done = true;
1462 		goto finish;
1463 	}
1464 
1465 	if (unlikely(dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY)) {
1466 		/* SHOULD NEVER HAPPEN ... but at least DaVinci has done it */
1467 		ERR("RX%d dma busy, csr %04x\n", epnum, rx_csr);
1468 		goto finish;
1469 	}
1470 
1471 	/* thorough shutdown for now ... given more precise fault handling
1472 	 * and better queueing support, we might keep a DMA pipeline going
1473 	 * while processing this irq for earlier completions.
1474 	 */
1475 
1476 	/* FIXME this is _way_ too much in-line logic for Mentor DMA */
1477 
1478 #ifndef CONFIG_USB_INVENTRA_DMA
1479 	if (rx_csr & MUSB_RXCSR_H_REQPKT)  {
1480 		/* REVISIT this happened for a while on some short reads...
1481 		 * the cleanup still needs investigation... looks bad...
1482 		 * and also duplicates dma cleanup code above ... plus,
1483 		 * shouldn't this be the "half full" double buffer case?
1484 		 */
1485 		if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1486 			dma->status = MUSB_DMA_STATUS_CORE_ABORT;
1487 			(void) musb->dma_controller->channel_abort(dma);
1488 			xfer_len = dma->actual_len;
1489 			done = true;
1490 		}
1491 
1492 		DBG(2, "RXCSR%d %04x, reqpkt, len %zu%s\n", epnum, rx_csr,
1493 				xfer_len, dma ? ", dma" : "");
1494 		rx_csr &= ~MUSB_RXCSR_H_REQPKT;
1495 
1496 		musb_ep_select(mbase, epnum);
1497 		musb_writew(epio, MUSB_RXCSR,
1498 				MUSB_RXCSR_H_WZC_BITS | rx_csr);
1499 	}
1500 #endif
1501 	if (dma && (rx_csr & MUSB_RXCSR_DMAENAB)) {
1502 		xfer_len = dma->actual_len;
1503 
1504 		val &= ~(MUSB_RXCSR_DMAENAB
1505 			| MUSB_RXCSR_H_AUTOREQ
1506 			| MUSB_RXCSR_AUTOCLEAR
1507 			| MUSB_RXCSR_RXPKTRDY);
1508 		musb_writew(hw_ep->regs, MUSB_RXCSR, val);
1509 
1510 #ifdef CONFIG_USB_INVENTRA_DMA
1511 		/* done if urb buffer is full or short packet is recd */
1512 		done = (urb->actual_length + xfer_len >=
1513 				urb->transfer_buffer_length
1514 			|| dma->actual_len < qh->maxpacket);
1515 
1516 		/* send IN token for next packet, without AUTOREQ */
1517 		if (!done) {
1518 			val |= MUSB_RXCSR_H_REQPKT;
1519 			musb_writew(epio, MUSB_RXCSR,
1520 				MUSB_RXCSR_H_WZC_BITS | val);
1521 		}
1522 
1523 		DBG(4, "ep %d dma %s, rxcsr %04x, rxcount %d\n", epnum,
1524 			done ? "off" : "reset",
1525 			musb_readw(epio, MUSB_RXCSR),
1526 			musb_readw(epio, MUSB_RXCOUNT));
1527 #else
1528 		done = true;
1529 #endif
1530 	} else if (urb->status == -EINPROGRESS) {
1531 		/* if no errors, be sure a packet is ready for unloading */
1532 		if (unlikely(!(rx_csr & MUSB_RXCSR_RXPKTRDY))) {
1533 			status = -EPROTO;
1534 			ERR("Rx interrupt with no errors or packet!\n");
1535 
1536 			/* FIXME this is another "SHOULD NEVER HAPPEN" */
1537 
1538 /* SCRUB (RX) */
1539 			/* do the proper sequence to abort the transfer */
1540 			musb_ep_select(mbase, epnum);
1541 			val &= ~MUSB_RXCSR_H_REQPKT;
1542 			musb_writew(epio, MUSB_RXCSR, val);
1543 			goto finish;
1544 		}
1545 
1546 		/* we are expecting IN packets */
1547 #ifdef CONFIG_USB_INVENTRA_DMA
1548 		if (dma) {
1549 			struct dma_controller	*c;
1550 			u16			rx_count;
1551 			int			ret;
1552 
1553 			rx_count = musb_readw(epio, MUSB_RXCOUNT);
1554 
1555 			DBG(2, "RX%d count %d, buffer 0x%x len %d/%d\n",
1556 					epnum, rx_count,
1557 					urb->transfer_dma
1558 						+ urb->actual_length,
1559 					qh->offset,
1560 					urb->transfer_buffer_length);
1561 
1562 			c = musb->dma_controller;
1563 
1564 			dma->desired_mode = 0;
1565 #ifdef USE_MODE1
1566 			/* because of the issue below, mode 1 will
1567 			 * only rarely behave with correct semantics.
1568 			 */
1569 			if ((urb->transfer_flags &
1570 						URB_SHORT_NOT_OK)
1571 				&& (urb->transfer_buffer_length -
1572 						urb->actual_length)
1573 					> qh->maxpacket)
1574 				dma->desired_mode = 1;
1575 #endif
1576 
1577 /* Disadvantage of using mode 1:
1578  *	It's basically usable only for mass storage class; essentially all
1579  *	other protocols also terminate transfers on short packets.
1580  *
1581  * Details:
1582  *	An extra IN token is sent at the end of the transfer (due to AUTOREQ)
1583  *	If you try to use mode 1 for (transfer_buffer_length - 512), and try
1584  *	to use the extra IN token to grab the last packet using mode 0, then
1585  *	the problem is that you cannot be sure when the device will send the
1586  *	last packet and RxPktRdy set. Sometimes the packet is recd too soon
1587  *	such that it gets lost when RxCSR is re-set at the end of the mode 1
1588  *	transfer, while sometimes it is recd just a little late so that if you
1589  *	try to configure for mode 0 soon after the mode 1 transfer is
1590  *	completed, you will find rxcount 0. Okay, so you might think why not
1591  *	wait for an interrupt when the pkt is recd. Well, you won't get any!
1592  */
1593 
1594 			val = musb_readw(epio, MUSB_RXCSR);
1595 			val &= ~MUSB_RXCSR_H_REQPKT;
1596 
1597 			if (dma->desired_mode == 0)
1598 				val &= ~MUSB_RXCSR_H_AUTOREQ;
1599 			else
1600 				val |= MUSB_RXCSR_H_AUTOREQ;
1601 			val |= MUSB_RXCSR_AUTOCLEAR | MUSB_RXCSR_DMAENAB;
1602 
1603 			musb_writew(epio, MUSB_RXCSR,
1604 				MUSB_RXCSR_H_WZC_BITS | val);
1605 
1606 			/* REVISIT if when actual_length != 0,
1607 			 * transfer_buffer_length needs to be
1608 			 * adjusted first...
1609 			 */
1610 			ret = c->channel_program(
1611 				dma, qh->maxpacket,
1612 				dma->desired_mode,
1613 				urb->transfer_dma
1614 					+ urb->actual_length,
1615 				(dma->desired_mode == 0)
1616 					? rx_count
1617 					: urb->transfer_buffer_length);
1618 
1619 			if (!ret) {
1620 				c->channel_release(dma);
1621 				hw_ep->rx_channel = NULL;
1622 				dma = NULL;
1623 				/* REVISIT reset CSR */
1624 			}
1625 		}
1626 #endif	/* Mentor DMA */
1627 
1628 		if (!dma) {
1629 			done = musb_host_packet_rx(musb, urb,
1630 					epnum, iso_err);
1631 			DBG(6, "read %spacket\n", done ? "last " : "");
1632 		}
1633 	}
1634 
1635 	if (dma && usb_pipeisoc(pipe)) {
1636 		struct usb_iso_packet_descriptor	*d;
1637 		int					iso_stat = status;
1638 
1639 		d = urb->iso_frame_desc + qh->iso_idx;
1640 		d->actual_length += xfer_len;
1641 		if (iso_err) {
1642 			iso_stat = -EILSEQ;
1643 			urb->error_count++;
1644 		}
1645 		d->status = iso_stat;
1646 	}
1647 
1648 finish:
1649 	urb->actual_length += xfer_len;
1650 	qh->offset += xfer_len;
1651 	if (done) {
1652 		if (urb->status == -EINPROGRESS)
1653 			urb->status = status;
1654 		musb_advance_schedule(musb, urb, hw_ep, USB_DIR_IN);
1655 	}
1656 }
1657 
1658 /* schedule nodes correspond to peripheral endpoints, like an OHCI QH.
1659  * the software schedule associates multiple such nodes with a given
1660  * host side hardware endpoint + direction; scheduling may activate
1661  * that hardware endpoint.
1662  */
1663 static int musb_schedule(
1664 	struct musb		*musb,
1665 	struct musb_qh		*qh,
1666 	int			is_in)
1667 {
1668 	int			idle;
1669 	int			best_diff;
1670 	int			best_end, epnum;
1671 	struct musb_hw_ep	*hw_ep = NULL;
1672 	struct list_head	*head = NULL;
1673 
1674 	/* use fixed hardware for control and bulk */
1675 	switch (qh->type) {
1676 	case USB_ENDPOINT_XFER_CONTROL:
1677 		head = &musb->control;
1678 		hw_ep = musb->control_ep;
1679 		break;
1680 	case USB_ENDPOINT_XFER_BULK:
1681 		hw_ep = musb->bulk_ep;
1682 		if (is_in)
1683 			head = &musb->in_bulk;
1684 		else
1685 			head = &musb->out_bulk;
1686 		break;
1687 	}
1688 	if (head) {
1689 		idle = list_empty(head);
1690 		list_add_tail(&qh->ring, head);
1691 		goto success;
1692 	}
1693 
1694 	/* else, periodic transfers get muxed to other endpoints */
1695 
1696 	/* FIXME this doesn't consider direction, so it can only
1697 	 * work for one half of the endpoint hardware, and assumes
1698 	 * the previous cases handled all non-shared endpoints...
1699 	 */
1700 
1701 	/* we know this qh hasn't been scheduled, so all we need to do
1702 	 * is choose which hardware endpoint to put it on ...
1703 	 *
1704 	 * REVISIT what we really want here is a regular schedule tree
1705 	 * like e.g. OHCI uses, but for now musb->periodic is just an
1706 	 * array of the _single_ logical endpoint associated with a
1707 	 * given physical one (identity mapping logical->physical).
1708 	 *
1709 	 * that simplistic approach makes TT scheduling a lot simpler;
1710 	 * there is none, and thus none of its complexity...
1711 	 */
1712 	best_diff = 4096;
1713 	best_end = -1;
1714 
1715 	for (epnum = 1; epnum < musb->nr_endpoints; epnum++) {
1716 		int	diff;
1717 
1718 		if (musb->periodic[epnum])
1719 			continue;
1720 		hw_ep = &musb->endpoints[epnum];
1721 		if (hw_ep == musb->bulk_ep)
1722 			continue;
1723 
1724 		if (is_in)
1725 			diff = hw_ep->max_packet_sz_rx - qh->maxpacket;
1726 		else
1727 			diff = hw_ep->max_packet_sz_tx - qh->maxpacket;
1728 
1729 		if (diff > 0 && best_diff > diff) {
1730 			best_diff = diff;
1731 			best_end = epnum;
1732 		}
1733 	}
1734 	if (best_end < 0)
1735 		return -ENOSPC;
1736 
1737 	idle = 1;
1738 	hw_ep = musb->endpoints + best_end;
1739 	musb->periodic[best_end] = qh;
1740 	DBG(4, "qh %p periodic slot %d\n", qh, best_end);
1741 success:
1742 	qh->hw_ep = hw_ep;
1743 	qh->hep->hcpriv = qh;
1744 	if (idle)
1745 		musb_start_urb(musb, is_in, qh);
1746 	return 0;
1747 }
1748 
1749 static int musb_urb_enqueue(
1750 	struct usb_hcd			*hcd,
1751 	struct urb			*urb,
1752 	gfp_t				mem_flags)
1753 {
1754 	unsigned long			flags;
1755 	struct musb			*musb = hcd_to_musb(hcd);
1756 	struct usb_host_endpoint	*hep = urb->ep;
1757 	struct musb_qh			*qh = hep->hcpriv;
1758 	struct usb_endpoint_descriptor	*epd = &hep->desc;
1759 	int				ret;
1760 	unsigned			type_reg;
1761 	unsigned			interval;
1762 
1763 	/* host role must be active */
1764 	if (!is_host_active(musb) || !musb->is_active)
1765 		return -ENODEV;
1766 
1767 	spin_lock_irqsave(&musb->lock, flags);
1768 	ret = usb_hcd_link_urb_to_ep(hcd, urb);
1769 	spin_unlock_irqrestore(&musb->lock, flags);
1770 	if (ret)
1771 		return ret;
1772 
1773 	/* DMA mapping was already done, if needed, and this urb is on
1774 	 * hep->urb_list ... so there's little to do unless hep wasn't
1775 	 * yet scheduled onto a live qh.
1776 	 *
1777 	 * REVISIT best to keep hep->hcpriv valid until the endpoint gets
1778 	 * disabled, testing for empty qh->ring and avoiding qh setup costs
1779 	 * except for the first urb queued after a config change.
1780 	 */
1781 	if (qh) {
1782 		urb->hcpriv = qh;
1783 		return 0;
1784 	}
1785 
1786 	/* Allocate and initialize qh, minimizing the work done each time
1787 	 * hw_ep gets reprogrammed, or with irqs blocked.  Then schedule it.
1788 	 *
1789 	 * REVISIT consider a dedicated qh kmem_cache, so it's harder
1790 	 * for bugs in other kernel code to break this driver...
1791 	 */
1792 	qh = kzalloc(sizeof *qh, mem_flags);
1793 	if (!qh) {
1794 		usb_hcd_unlink_urb_from_ep(hcd, urb);
1795 		return -ENOMEM;
1796 	}
1797 
1798 	qh->hep = hep;
1799 	qh->dev = urb->dev;
1800 	INIT_LIST_HEAD(&qh->ring);
1801 	qh->is_ready = 1;
1802 
1803 	qh->maxpacket = le16_to_cpu(epd->wMaxPacketSize);
1804 
1805 	/* no high bandwidth support yet */
1806 	if (qh->maxpacket & ~0x7ff) {
1807 		ret = -EMSGSIZE;
1808 		goto done;
1809 	}
1810 
1811 	qh->epnum = epd->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK;
1812 	qh->type = epd->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK;
1813 
1814 	/* NOTE: urb->dev->devnum is wrong during SET_ADDRESS */
1815 	qh->addr_reg = (u8) usb_pipedevice(urb->pipe);
1816 
1817 	/* precompute rxtype/txtype/type0 register */
1818 	type_reg = (qh->type << 4) | qh->epnum;
1819 	switch (urb->dev->speed) {
1820 	case USB_SPEED_LOW:
1821 		type_reg |= 0xc0;
1822 		break;
1823 	case USB_SPEED_FULL:
1824 		type_reg |= 0x80;
1825 		break;
1826 	default:
1827 		type_reg |= 0x40;
1828 	}
1829 	qh->type_reg = type_reg;
1830 
1831 	/* precompute rxinterval/txinterval register */
1832 	interval = min((u8)16, epd->bInterval);	/* log encoding */
1833 	switch (qh->type) {
1834 	case USB_ENDPOINT_XFER_INT:
1835 		/* fullspeed uses linear encoding */
1836 		if (USB_SPEED_FULL == urb->dev->speed) {
1837 			interval = epd->bInterval;
1838 			if (!interval)
1839 				interval = 1;
1840 		}
1841 		/* FALLTHROUGH */
1842 	case USB_ENDPOINT_XFER_ISOC:
1843 		/* iso always uses log encoding */
1844 		break;
1845 	default:
1846 		/* REVISIT we actually want to use NAK limits, hinting to the
1847 		 * transfer scheduling logic to try some other qh, e.g. try
1848 		 * for 2 msec first:
1849 		 *
1850 		 * interval = (USB_SPEED_HIGH == urb->dev->speed) ? 16 : 2;
1851 		 *
1852 		 * The downside of disabling this is that transfer scheduling
1853 		 * gets VERY unfair for nonperiodic transfers; a misbehaving
1854 		 * peripheral could make that hurt.  Or for reads, one that's
1855 		 * perfectly normal:  network and other drivers keep reads
1856 		 * posted at all times, having one pending for a week should
1857 		 * be perfectly safe.
1858 		 *
1859 		 * The upside of disabling it is avoidng transfer scheduling
1860 		 * code to put this aside for while.
1861 		 */
1862 		interval = 0;
1863 	}
1864 	qh->intv_reg = interval;
1865 
1866 	/* precompute addressing for external hub/tt ports */
1867 	if (musb->is_multipoint) {
1868 		struct usb_device	*parent = urb->dev->parent;
1869 
1870 		if (parent != hcd->self.root_hub) {
1871 			qh->h_addr_reg = (u8) parent->devnum;
1872 
1873 			/* set up tt info if needed */
1874 			if (urb->dev->tt) {
1875 				qh->h_port_reg = (u8) urb->dev->ttport;
1876 				qh->h_addr_reg |= 0x80;
1877 			}
1878 		}
1879 	}
1880 
1881 	/* invariant: hep->hcpriv is null OR the qh that's already scheduled.
1882 	 * until we get real dma queues (with an entry for each urb/buffer),
1883 	 * we only have work to do in the former case.
1884 	 */
1885 	spin_lock_irqsave(&musb->lock, flags);
1886 	if (hep->hcpriv) {
1887 		/* some concurrent activity submitted another urb to hep...
1888 		 * odd, rare, error prone, but legal.
1889 		 */
1890 		kfree(qh);
1891 		ret = 0;
1892 	} else
1893 		ret = musb_schedule(musb, qh,
1894 				epd->bEndpointAddress & USB_ENDPOINT_DIR_MASK);
1895 
1896 	if (ret == 0) {
1897 		urb->hcpriv = qh;
1898 		/* FIXME set urb->start_frame for iso/intr, it's tested in
1899 		 * musb_start_urb(), but otherwise only konicawc cares ...
1900 		 */
1901 	}
1902 	spin_unlock_irqrestore(&musb->lock, flags);
1903 
1904 done:
1905 	if (ret != 0) {
1906 		usb_hcd_unlink_urb_from_ep(hcd, urb);
1907 		kfree(qh);
1908 	}
1909 	return ret;
1910 }
1911 
1912 
1913 /*
1914  * abort a transfer that's at the head of a hardware queue.
1915  * called with controller locked, irqs blocked
1916  * that hardware queue advances to the next transfer, unless prevented
1917  */
1918 static int musb_cleanup_urb(struct urb *urb, struct musb_qh *qh, int is_in)
1919 {
1920 	struct musb_hw_ep	*ep = qh->hw_ep;
1921 	void __iomem		*epio = ep->regs;
1922 	unsigned		hw_end = ep->epnum;
1923 	void __iomem		*regs = ep->musb->mregs;
1924 	u16			csr;
1925 	int			status = 0;
1926 
1927 	musb_ep_select(regs, hw_end);
1928 
1929 	if (is_dma_capable()) {
1930 		struct dma_channel	*dma;
1931 
1932 		dma = is_in ? ep->rx_channel : ep->tx_channel;
1933 		if (dma) {
1934 			status = ep->musb->dma_controller->channel_abort(dma);
1935 			DBG(status ? 1 : 3,
1936 				"abort %cX%d DMA for urb %p --> %d\n",
1937 				is_in ? 'R' : 'T', ep->epnum,
1938 				urb, status);
1939 			urb->actual_length += dma->actual_len;
1940 		}
1941 	}
1942 
1943 	/* turn off DMA requests, discard state, stop polling ... */
1944 	if (is_in) {
1945 		/* giveback saves bulk toggle */
1946 		csr = musb_h_flush_rxfifo(ep, 0);
1947 
1948 		/* REVISIT we still get an irq; should likely clear the
1949 		 * endpoint's irq status here to avoid bogus irqs.
1950 		 * clearing that status is platform-specific...
1951 		 */
1952 	} else {
1953 		musb_h_tx_flush_fifo(ep);
1954 		csr = musb_readw(epio, MUSB_TXCSR);
1955 		csr &= ~(MUSB_TXCSR_AUTOSET
1956 			| MUSB_TXCSR_DMAENAB
1957 			| MUSB_TXCSR_H_RXSTALL
1958 			| MUSB_TXCSR_H_NAKTIMEOUT
1959 			| MUSB_TXCSR_H_ERROR
1960 			| MUSB_TXCSR_TXPKTRDY);
1961 		musb_writew(epio, MUSB_TXCSR, csr);
1962 		/* REVISIT may need to clear FLUSHFIFO ... */
1963 		musb_writew(epio, MUSB_TXCSR, csr);
1964 		/* flush cpu writebuffer */
1965 		csr = musb_readw(epio, MUSB_TXCSR);
1966 	}
1967 	if (status == 0)
1968 		musb_advance_schedule(ep->musb, urb, ep, is_in);
1969 	return status;
1970 }
1971 
1972 static int musb_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
1973 {
1974 	struct musb		*musb = hcd_to_musb(hcd);
1975 	struct musb_qh		*qh;
1976 	struct list_head	*sched;
1977 	unsigned long		flags;
1978 	int			ret;
1979 
1980 	DBG(4, "urb=%p, dev%d ep%d%s\n", urb,
1981 			usb_pipedevice(urb->pipe),
1982 			usb_pipeendpoint(urb->pipe),
1983 			usb_pipein(urb->pipe) ? "in" : "out");
1984 
1985 	spin_lock_irqsave(&musb->lock, flags);
1986 	ret = usb_hcd_check_unlink_urb(hcd, urb, status);
1987 	if (ret)
1988 		goto done;
1989 
1990 	qh = urb->hcpriv;
1991 	if (!qh)
1992 		goto done;
1993 
1994 	/* Any URB not actively programmed into endpoint hardware can be
1995 	 * immediately given back.  Such an URB must be at the head of its
1996 	 * endpoint queue, unless someday we get real DMA queues.  And even
1997 	 * then, it might not be known to the hardware...
1998 	 *
1999 	 * Otherwise abort current transfer, pending dma, etc.; urb->status
2000 	 * has already been updated.  This is a synchronous abort; it'd be
2001 	 * OK to hold off until after some IRQ, though.
2002 	 */
2003 	if (!qh->is_ready || urb->urb_list.prev != &qh->hep->urb_list)
2004 		ret = -EINPROGRESS;
2005 	else {
2006 		switch (qh->type) {
2007 		case USB_ENDPOINT_XFER_CONTROL:
2008 			sched = &musb->control;
2009 			break;
2010 		case USB_ENDPOINT_XFER_BULK:
2011 			if (usb_pipein(urb->pipe))
2012 				sched = &musb->in_bulk;
2013 			else
2014 				sched = &musb->out_bulk;
2015 			break;
2016 		default:
2017 			/* REVISIT when we get a schedule tree, periodic
2018 			 * transfers won't always be at the head of a
2019 			 * singleton queue...
2020 			 */
2021 			sched = NULL;
2022 			break;
2023 		}
2024 	}
2025 
2026 	/* NOTE:  qh is invalid unless !list_empty(&hep->urb_list) */
2027 	if (ret < 0 || (sched && qh != first_qh(sched))) {
2028 		int	ready = qh->is_ready;
2029 
2030 		ret = 0;
2031 		qh->is_ready = 0;
2032 		__musb_giveback(musb, urb, 0);
2033 		qh->is_ready = ready;
2034 	} else
2035 		ret = musb_cleanup_urb(urb, qh, urb->pipe & USB_DIR_IN);
2036 done:
2037 	spin_unlock_irqrestore(&musb->lock, flags);
2038 	return ret;
2039 }
2040 
2041 /* disable an endpoint */
2042 static void
2043 musb_h_disable(struct usb_hcd *hcd, struct usb_host_endpoint *hep)
2044 {
2045 	u8			epnum = hep->desc.bEndpointAddress;
2046 	unsigned long		flags;
2047 	struct musb		*musb = hcd_to_musb(hcd);
2048 	u8			is_in = epnum & USB_DIR_IN;
2049 	struct musb_qh		*qh = hep->hcpriv;
2050 	struct urb		*urb, *tmp;
2051 	struct list_head	*sched;
2052 
2053 	if (!qh)
2054 		return;
2055 
2056 	spin_lock_irqsave(&musb->lock, flags);
2057 
2058 	switch (qh->type) {
2059 	case USB_ENDPOINT_XFER_CONTROL:
2060 		sched = &musb->control;
2061 		break;
2062 	case USB_ENDPOINT_XFER_BULK:
2063 		if (is_in)
2064 			sched = &musb->in_bulk;
2065 		else
2066 			sched = &musb->out_bulk;
2067 		break;
2068 	default:
2069 		/* REVISIT when we get a schedule tree, periodic transfers
2070 		 * won't always be at the head of a singleton queue...
2071 		 */
2072 		sched = NULL;
2073 		break;
2074 	}
2075 
2076 	/* NOTE:  qh is invalid unless !list_empty(&hep->urb_list) */
2077 
2078 	/* kick first urb off the hardware, if needed */
2079 	qh->is_ready = 0;
2080 	if (!sched || qh == first_qh(sched)) {
2081 		urb = next_urb(qh);
2082 
2083 		/* make software (then hardware) stop ASAP */
2084 		if (!urb->unlinked)
2085 			urb->status = -ESHUTDOWN;
2086 
2087 		/* cleanup */
2088 		musb_cleanup_urb(urb, qh, urb->pipe & USB_DIR_IN);
2089 	} else
2090 		urb = NULL;
2091 
2092 	/* then just nuke all the others */
2093 	list_for_each_entry_safe_from(urb, tmp, &hep->urb_list, urb_list)
2094 		musb_giveback(qh, urb, -ESHUTDOWN);
2095 
2096 	spin_unlock_irqrestore(&musb->lock, flags);
2097 }
2098 
2099 static int musb_h_get_frame_number(struct usb_hcd *hcd)
2100 {
2101 	struct musb	*musb = hcd_to_musb(hcd);
2102 
2103 	return musb_readw(musb->mregs, MUSB_FRAME);
2104 }
2105 
2106 static int musb_h_start(struct usb_hcd *hcd)
2107 {
2108 	struct musb	*musb = hcd_to_musb(hcd);
2109 
2110 	/* NOTE: musb_start() is called when the hub driver turns
2111 	 * on port power, or when (OTG) peripheral starts.
2112 	 */
2113 	hcd->state = HC_STATE_RUNNING;
2114 	musb->port1_status = 0;
2115 	return 0;
2116 }
2117 
2118 static void musb_h_stop(struct usb_hcd *hcd)
2119 {
2120 	musb_stop(hcd_to_musb(hcd));
2121 	hcd->state = HC_STATE_HALT;
2122 }
2123 
2124 static int musb_bus_suspend(struct usb_hcd *hcd)
2125 {
2126 	struct musb	*musb = hcd_to_musb(hcd);
2127 
2128 	if (musb->xceiv.state == OTG_STATE_A_SUSPEND)
2129 		return 0;
2130 
2131 	if (is_host_active(musb) && musb->is_active) {
2132 		WARNING("trying to suspend as %s is_active=%i\n",
2133 			otg_state_string(musb), musb->is_active);
2134 		return -EBUSY;
2135 	} else
2136 		return 0;
2137 }
2138 
2139 static int musb_bus_resume(struct usb_hcd *hcd)
2140 {
2141 	/* resuming child port does the work */
2142 	return 0;
2143 }
2144 
2145 const struct hc_driver musb_hc_driver = {
2146 	.description		= "musb-hcd",
2147 	.product_desc		= "MUSB HDRC host driver",
2148 	.hcd_priv_size		= sizeof(struct musb),
2149 	.flags			= HCD_USB2 | HCD_MEMORY,
2150 
2151 	/* not using irq handler or reset hooks from usbcore, since
2152 	 * those must be shared with peripheral code for OTG configs
2153 	 */
2154 
2155 	.start			= musb_h_start,
2156 	.stop			= musb_h_stop,
2157 
2158 	.get_frame_number	= musb_h_get_frame_number,
2159 
2160 	.urb_enqueue		= musb_urb_enqueue,
2161 	.urb_dequeue		= musb_urb_dequeue,
2162 	.endpoint_disable	= musb_h_disable,
2163 
2164 	.hub_status_data	= musb_hub_status_data,
2165 	.hub_control		= musb_hub_control,
2166 	.bus_suspend		= musb_bus_suspend,
2167 	.bus_resume		= musb_bus_resume,
2168 	/* .start_port_reset	= NULL, */
2169 	/* .hub_irq_enable	= NULL, */
2170 };
2171