xref: /linux/drivers/usb/musb/musb_host.c (revision 95e9fd10f06cb5642028b6b851e32b8c8afb4571)
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  * Copyright (C) 2008-2009 MontaVista Software, Inc. <source@mvista.com>
8  *
9  * This program is free software; you can redistribute it and/or
10  * modify it under the terms of the GNU General Public License
11  * version 2 as published by the Free Software Foundation.
12  *
13  * This program is distributed in the hope that it will be useful, but
14  * WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16  * General Public License for more details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this program; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
21  * 02110-1301 USA
22  *
23  * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
24  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
25  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
26  * NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
27  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
28  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
29  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
30  * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
32  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33  *
34  */
35 
36 #include <linux/module.h>
37 #include <linux/kernel.h>
38 #include <linux/delay.h>
39 #include <linux/sched.h>
40 #include <linux/slab.h>
41 #include <linux/errno.h>
42 #include <linux/init.h>
43 #include <linux/list.h>
44 #include <linux/dma-mapping.h>
45 
46 #include "musb_core.h"
47 #include "musb_host.h"
48 
49 
50 /* MUSB HOST status 22-mar-2006
51  *
52  * - There's still lots of partial code duplication for fault paths, so
53  *   they aren't handled as consistently as they need to be.
54  *
55  * - PIO mostly behaved when last tested.
56  *     + including ep0, with all usbtest cases 9, 10
57  *     + usbtest 14 (ep0out) doesn't seem to run at all
58  *     + double buffered OUT/TX endpoints saw stalls(!) with certain usbtest
59  *       configurations, but otherwise double buffering passes basic tests.
60  *     + for 2.6.N, for N > ~10, needs API changes for hcd framework.
61  *
62  * - DMA (CPPI) ... partially behaves, not currently recommended
63  *     + about 1/15 the speed of typical EHCI implementations (PCI)
64  *     + RX, all too often reqpkt seems to misbehave after tx
65  *     + TX, no known issues (other than evident silicon issue)
66  *
67  * - DMA (Mentor/OMAP) ...has at least toggle update problems
68  *
69  * - [23-feb-2009] minimal traffic scheduling to avoid bulk RX packet
70  *   starvation ... nothing yet for TX, interrupt, or bulk.
71  *
72  * - Not tested with HNP, but some SRP paths seem to behave.
73  *
74  * NOTE 24-August-2006:
75  *
76  * - Bulk traffic finally uses both sides of hardware ep1, freeing up an
77  *   extra endpoint for periodic use enabling hub + keybd + mouse.  That
78  *   mostly works, except that with "usbnet" it's easy to trigger cases
79  *   with "ping" where RX loses.  (a) ping to davinci, even "ping -f",
80  *   fine; but (b) ping _from_ davinci, even "ping -c 1", ICMP RX loses
81  *   although ARP RX wins.  (That test was done with a full speed link.)
82  */
83 
84 
85 /*
86  * NOTE on endpoint usage:
87  *
88  * CONTROL transfers all go through ep0.  BULK ones go through dedicated IN
89  * and OUT endpoints ... hardware is dedicated for those "async" queue(s).
90  * (Yes, bulk _could_ use more of the endpoints than that, and would even
91  * benefit from it.)
92  *
93  * INTERUPPT and ISOCHRONOUS transfers are scheduled to the other endpoints.
94  * So far that scheduling is both dumb and optimistic:  the endpoint will be
95  * "claimed" until its software queue is no longer refilled.  No multiplexing
96  * of transfers between endpoints, or anything clever.
97  */
98 
99 
100 static void musb_ep_program(struct musb *musb, u8 epnum,
101 			struct urb *urb, int is_out,
102 			u8 *buf, u32 offset, u32 len);
103 
104 /*
105  * Clear TX fifo. Needed to avoid BABBLE errors.
106  */
107 static void musb_h_tx_flush_fifo(struct musb_hw_ep *ep)
108 {
109 	struct musb	*musb = ep->musb;
110 	void __iomem	*epio = ep->regs;
111 	u16		csr;
112 	u16		lastcsr = 0;
113 	int		retries = 1000;
114 
115 	csr = musb_readw(epio, MUSB_TXCSR);
116 	while (csr & MUSB_TXCSR_FIFONOTEMPTY) {
117 		if (csr != lastcsr)
118 			dev_dbg(musb->controller, "Host TX FIFONOTEMPTY csr: %02x\n", csr);
119 		lastcsr = csr;
120 		csr |= MUSB_TXCSR_FLUSHFIFO;
121 		musb_writew(epio, MUSB_TXCSR, csr);
122 		csr = musb_readw(epio, MUSB_TXCSR);
123 		if (WARN(retries-- < 1,
124 				"Could not flush host TX%d fifo: csr: %04x\n",
125 				ep->epnum, csr))
126 			return;
127 		mdelay(1);
128 	}
129 }
130 
131 static void musb_h_ep0_flush_fifo(struct musb_hw_ep *ep)
132 {
133 	void __iomem	*epio = ep->regs;
134 	u16		csr;
135 	int		retries = 5;
136 
137 	/* scrub any data left in the fifo */
138 	do {
139 		csr = musb_readw(epio, MUSB_TXCSR);
140 		if (!(csr & (MUSB_CSR0_TXPKTRDY | MUSB_CSR0_RXPKTRDY)))
141 			break;
142 		musb_writew(epio, MUSB_TXCSR, MUSB_CSR0_FLUSHFIFO);
143 		csr = musb_readw(epio, MUSB_TXCSR);
144 		udelay(10);
145 	} while (--retries);
146 
147 	WARN(!retries, "Could not flush host TX%d fifo: csr: %04x\n",
148 			ep->epnum, csr);
149 
150 	/* and reset for the next transfer */
151 	musb_writew(epio, MUSB_TXCSR, 0);
152 }
153 
154 /*
155  * Start transmit. Caller is responsible for locking shared resources.
156  * musb must be locked.
157  */
158 static inline void musb_h_tx_start(struct musb_hw_ep *ep)
159 {
160 	u16	txcsr;
161 
162 	/* NOTE: no locks here; caller should lock and select EP */
163 	if (ep->epnum) {
164 		txcsr = musb_readw(ep->regs, MUSB_TXCSR);
165 		txcsr |= MUSB_TXCSR_TXPKTRDY | MUSB_TXCSR_H_WZC_BITS;
166 		musb_writew(ep->regs, MUSB_TXCSR, txcsr);
167 	} else {
168 		txcsr = MUSB_CSR0_H_SETUPPKT | MUSB_CSR0_TXPKTRDY;
169 		musb_writew(ep->regs, MUSB_CSR0, txcsr);
170 	}
171 
172 }
173 
174 static inline void musb_h_tx_dma_start(struct musb_hw_ep *ep)
175 {
176 	u16	txcsr;
177 
178 	/* NOTE: no locks here; caller should lock and select EP */
179 	txcsr = musb_readw(ep->regs, MUSB_TXCSR);
180 	txcsr |= MUSB_TXCSR_DMAENAB | MUSB_TXCSR_H_WZC_BITS;
181 	if (is_cppi_enabled())
182 		txcsr |= MUSB_TXCSR_DMAMODE;
183 	musb_writew(ep->regs, MUSB_TXCSR, txcsr);
184 }
185 
186 static void musb_ep_set_qh(struct musb_hw_ep *ep, int is_in, struct musb_qh *qh)
187 {
188 	if (is_in != 0 || ep->is_shared_fifo)
189 		ep->in_qh  = qh;
190 	if (is_in == 0 || ep->is_shared_fifo)
191 		ep->out_qh = qh;
192 }
193 
194 static struct musb_qh *musb_ep_get_qh(struct musb_hw_ep *ep, int is_in)
195 {
196 	return is_in ? ep->in_qh : ep->out_qh;
197 }
198 
199 /*
200  * Start the URB at the front of an endpoint's queue
201  * end must be claimed from the caller.
202  *
203  * Context: controller locked, irqs blocked
204  */
205 static void
206 musb_start_urb(struct musb *musb, int is_in, struct musb_qh *qh)
207 {
208 	u16			frame;
209 	u32			len;
210 	void __iomem		*mbase =  musb->mregs;
211 	struct urb		*urb = next_urb(qh);
212 	void			*buf = urb->transfer_buffer;
213 	u32			offset = 0;
214 	struct musb_hw_ep	*hw_ep = qh->hw_ep;
215 	unsigned		pipe = urb->pipe;
216 	u8			address = usb_pipedevice(pipe);
217 	int			epnum = hw_ep->epnum;
218 
219 	/* initialize software qh state */
220 	qh->offset = 0;
221 	qh->segsize = 0;
222 
223 	/* gather right source of data */
224 	switch (qh->type) {
225 	case USB_ENDPOINT_XFER_CONTROL:
226 		/* control transfers always start with SETUP */
227 		is_in = 0;
228 		musb->ep0_stage = MUSB_EP0_START;
229 		buf = urb->setup_packet;
230 		len = 8;
231 		break;
232 	case USB_ENDPOINT_XFER_ISOC:
233 		qh->iso_idx = 0;
234 		qh->frame = 0;
235 		offset = urb->iso_frame_desc[0].offset;
236 		len = urb->iso_frame_desc[0].length;
237 		break;
238 	default:		/* bulk, interrupt */
239 		/* actual_length may be nonzero on retry paths */
240 		buf = urb->transfer_buffer + urb->actual_length;
241 		len = urb->transfer_buffer_length - urb->actual_length;
242 	}
243 
244 	dev_dbg(musb->controller, "qh %p urb %p dev%d ep%d%s%s, hw_ep %d, %p/%d\n",
245 			qh, urb, address, qh->epnum,
246 			is_in ? "in" : "out",
247 			({char *s; switch (qh->type) {
248 			case USB_ENDPOINT_XFER_CONTROL:	s = ""; break;
249 			case USB_ENDPOINT_XFER_BULK:	s = "-bulk"; break;
250 			case USB_ENDPOINT_XFER_ISOC:	s = "-iso"; break;
251 			default:			s = "-intr"; break;
252 			}; s; }),
253 			epnum, buf + offset, len);
254 
255 	/* Configure endpoint */
256 	musb_ep_set_qh(hw_ep, is_in, qh);
257 	musb_ep_program(musb, epnum, urb, !is_in, buf, offset, len);
258 
259 	/* transmit may have more work: start it when it is time */
260 	if (is_in)
261 		return;
262 
263 	/* determine if the time is right for a periodic transfer */
264 	switch (qh->type) {
265 	case USB_ENDPOINT_XFER_ISOC:
266 	case USB_ENDPOINT_XFER_INT:
267 		dev_dbg(musb->controller, "check whether there's still time for periodic Tx\n");
268 		frame = musb_readw(mbase, MUSB_FRAME);
269 		/* FIXME this doesn't implement that scheduling policy ...
270 		 * or handle framecounter wrapping
271 		 */
272 		if ((urb->transfer_flags & URB_ISO_ASAP)
273 				|| (frame >= urb->start_frame)) {
274 			/* REVISIT the SOF irq handler shouldn't duplicate
275 			 * this code; and we don't init urb->start_frame...
276 			 */
277 			qh->frame = 0;
278 			goto start;
279 		} else {
280 			qh->frame = urb->start_frame;
281 			/* enable SOF interrupt so we can count down */
282 			dev_dbg(musb->controller, "SOF for %d\n", epnum);
283 #if 1 /* ifndef	CONFIG_ARCH_DAVINCI */
284 			musb_writeb(mbase, MUSB_INTRUSBE, 0xff);
285 #endif
286 		}
287 		break;
288 	default:
289 start:
290 		dev_dbg(musb->controller, "Start TX%d %s\n", epnum,
291 			hw_ep->tx_channel ? "dma" : "pio");
292 
293 		if (!hw_ep->tx_channel)
294 			musb_h_tx_start(hw_ep);
295 		else if (is_cppi_enabled() || tusb_dma_omap())
296 			musb_h_tx_dma_start(hw_ep);
297 	}
298 }
299 
300 /* Context: caller owns controller lock, IRQs are blocked */
301 static void musb_giveback(struct musb *musb, struct urb *urb, int status)
302 __releases(musb->lock)
303 __acquires(musb->lock)
304 {
305 	dev_dbg(musb->controller,
306 			"complete %p %pF (%d), dev%d ep%d%s, %d/%d\n",
307 			urb, urb->complete, status,
308 			usb_pipedevice(urb->pipe),
309 			usb_pipeendpoint(urb->pipe),
310 			usb_pipein(urb->pipe) ? "in" : "out",
311 			urb->actual_length, urb->transfer_buffer_length
312 			);
313 
314 	usb_hcd_unlink_urb_from_ep(musb_to_hcd(musb), urb);
315 	spin_unlock(&musb->lock);
316 	usb_hcd_giveback_urb(musb_to_hcd(musb), urb, status);
317 	spin_lock(&musb->lock);
318 }
319 
320 /* For bulk/interrupt endpoints only */
321 static inline void musb_save_toggle(struct musb_qh *qh, int is_in,
322 				    struct urb *urb)
323 {
324 	void __iomem		*epio = qh->hw_ep->regs;
325 	u16			csr;
326 
327 	/*
328 	 * FIXME: the current Mentor DMA code seems to have
329 	 * problems getting toggle correct.
330 	 */
331 
332 	if (is_in)
333 		csr = musb_readw(epio, MUSB_RXCSR) & MUSB_RXCSR_H_DATATOGGLE;
334 	else
335 		csr = musb_readw(epio, MUSB_TXCSR) & MUSB_TXCSR_H_DATATOGGLE;
336 
337 	usb_settoggle(urb->dev, qh->epnum, !is_in, csr ? 1 : 0);
338 }
339 
340 /*
341  * Advance this hardware endpoint's queue, completing the specified URB and
342  * advancing to either the next URB queued to that qh, or else invalidating
343  * that qh and advancing to the next qh scheduled after the current one.
344  *
345  * Context: caller owns controller lock, IRQs are blocked
346  */
347 static void musb_advance_schedule(struct musb *musb, struct urb *urb,
348 				  struct musb_hw_ep *hw_ep, int is_in)
349 {
350 	struct musb_qh		*qh = musb_ep_get_qh(hw_ep, is_in);
351 	struct musb_hw_ep	*ep = qh->hw_ep;
352 	int			ready = qh->is_ready;
353 	int			status;
354 
355 	status = (urb->status == -EINPROGRESS) ? 0 : urb->status;
356 
357 	/* save toggle eagerly, for paranoia */
358 	switch (qh->type) {
359 	case USB_ENDPOINT_XFER_BULK:
360 	case USB_ENDPOINT_XFER_INT:
361 		musb_save_toggle(qh, is_in, urb);
362 		break;
363 	case USB_ENDPOINT_XFER_ISOC:
364 		if (status == 0 && urb->error_count)
365 			status = -EXDEV;
366 		break;
367 	}
368 
369 	qh->is_ready = 0;
370 	musb_giveback(musb, urb, status);
371 	qh->is_ready = ready;
372 
373 	/* reclaim resources (and bandwidth) ASAP; deschedule it, and
374 	 * invalidate qh as soon as list_empty(&hep->urb_list)
375 	 */
376 	if (list_empty(&qh->hep->urb_list)) {
377 		struct list_head	*head;
378 		struct dma_controller	*dma = musb->dma_controller;
379 
380 		if (is_in) {
381 			ep->rx_reinit = 1;
382 			if (ep->rx_channel) {
383 				dma->channel_release(ep->rx_channel);
384 				ep->rx_channel = NULL;
385 			}
386 		} else {
387 			ep->tx_reinit = 1;
388 			if (ep->tx_channel) {
389 				dma->channel_release(ep->tx_channel);
390 				ep->tx_channel = NULL;
391 			}
392 		}
393 
394 		/* Clobber old pointers to this qh */
395 		musb_ep_set_qh(ep, is_in, NULL);
396 		qh->hep->hcpriv = NULL;
397 
398 		switch (qh->type) {
399 
400 		case USB_ENDPOINT_XFER_CONTROL:
401 		case USB_ENDPOINT_XFER_BULK:
402 			/* fifo policy for these lists, except that NAKing
403 			 * should rotate a qh to the end (for fairness).
404 			 */
405 			if (qh->mux == 1) {
406 				head = qh->ring.prev;
407 				list_del(&qh->ring);
408 				kfree(qh);
409 				qh = first_qh(head);
410 				break;
411 			}
412 
413 		case USB_ENDPOINT_XFER_ISOC:
414 		case USB_ENDPOINT_XFER_INT:
415 			/* this is where periodic bandwidth should be
416 			 * de-allocated if it's tracked and allocated;
417 			 * and where we'd update the schedule tree...
418 			 */
419 			kfree(qh);
420 			qh = NULL;
421 			break;
422 		}
423 	}
424 
425 	if (qh != NULL && qh->is_ready) {
426 		dev_dbg(musb->controller, "... next ep%d %cX urb %p\n",
427 		    hw_ep->epnum, is_in ? 'R' : 'T', next_urb(qh));
428 		musb_start_urb(musb, is_in, qh);
429 	}
430 }
431 
432 static u16 musb_h_flush_rxfifo(struct musb_hw_ep *hw_ep, u16 csr)
433 {
434 	/* we don't want fifo to fill itself again;
435 	 * ignore dma (various models),
436 	 * leave toggle alone (may not have been saved yet)
437 	 */
438 	csr |= MUSB_RXCSR_FLUSHFIFO | MUSB_RXCSR_RXPKTRDY;
439 	csr &= ~(MUSB_RXCSR_H_REQPKT
440 		| MUSB_RXCSR_H_AUTOREQ
441 		| MUSB_RXCSR_AUTOCLEAR);
442 
443 	/* write 2x to allow double buffering */
444 	musb_writew(hw_ep->regs, MUSB_RXCSR, csr);
445 	musb_writew(hw_ep->regs, MUSB_RXCSR, csr);
446 
447 	/* flush writebuffer */
448 	return musb_readw(hw_ep->regs, MUSB_RXCSR);
449 }
450 
451 /*
452  * PIO RX for a packet (or part of it).
453  */
454 static bool
455 musb_host_packet_rx(struct musb *musb, struct urb *urb, u8 epnum, u8 iso_err)
456 {
457 	u16			rx_count;
458 	u8			*buf;
459 	u16			csr;
460 	bool			done = false;
461 	u32			length;
462 	int			do_flush = 0;
463 	struct musb_hw_ep	*hw_ep = musb->endpoints + epnum;
464 	void __iomem		*epio = hw_ep->regs;
465 	struct musb_qh		*qh = hw_ep->in_qh;
466 	int			pipe = urb->pipe;
467 	void			*buffer = urb->transfer_buffer;
468 
469 	/* musb_ep_select(mbase, epnum); */
470 	rx_count = musb_readw(epio, MUSB_RXCOUNT);
471 	dev_dbg(musb->controller, "RX%d count %d, buffer %p len %d/%d\n", epnum, rx_count,
472 			urb->transfer_buffer, qh->offset,
473 			urb->transfer_buffer_length);
474 
475 	/* unload FIFO */
476 	if (usb_pipeisoc(pipe)) {
477 		int					status = 0;
478 		struct usb_iso_packet_descriptor	*d;
479 
480 		if (iso_err) {
481 			status = -EILSEQ;
482 			urb->error_count++;
483 		}
484 
485 		d = urb->iso_frame_desc + qh->iso_idx;
486 		buf = buffer + d->offset;
487 		length = d->length;
488 		if (rx_count > length) {
489 			if (status == 0) {
490 				status = -EOVERFLOW;
491 				urb->error_count++;
492 			}
493 			dev_dbg(musb->controller, "** OVERFLOW %d into %d\n", rx_count, length);
494 			do_flush = 1;
495 		} else
496 			length = rx_count;
497 		urb->actual_length += length;
498 		d->actual_length = length;
499 
500 		d->status = status;
501 
502 		/* see if we are done */
503 		done = (++qh->iso_idx >= urb->number_of_packets);
504 	} else {
505 		/* non-isoch */
506 		buf = buffer + qh->offset;
507 		length = urb->transfer_buffer_length - qh->offset;
508 		if (rx_count > length) {
509 			if (urb->status == -EINPROGRESS)
510 				urb->status = -EOVERFLOW;
511 			dev_dbg(musb->controller, "** OVERFLOW %d into %d\n", rx_count, length);
512 			do_flush = 1;
513 		} else
514 			length = rx_count;
515 		urb->actual_length += length;
516 		qh->offset += length;
517 
518 		/* see if we are done */
519 		done = (urb->actual_length == urb->transfer_buffer_length)
520 			|| (rx_count < qh->maxpacket)
521 			|| (urb->status != -EINPROGRESS);
522 		if (done
523 				&& (urb->status == -EINPROGRESS)
524 				&& (urb->transfer_flags & URB_SHORT_NOT_OK)
525 				&& (urb->actual_length
526 					< urb->transfer_buffer_length))
527 			urb->status = -EREMOTEIO;
528 	}
529 
530 	musb_read_fifo(hw_ep, length, buf);
531 
532 	csr = musb_readw(epio, MUSB_RXCSR);
533 	csr |= MUSB_RXCSR_H_WZC_BITS;
534 	if (unlikely(do_flush))
535 		musb_h_flush_rxfifo(hw_ep, csr);
536 	else {
537 		/* REVISIT this assumes AUTOCLEAR is never set */
538 		csr &= ~(MUSB_RXCSR_RXPKTRDY | MUSB_RXCSR_H_REQPKT);
539 		if (!done)
540 			csr |= MUSB_RXCSR_H_REQPKT;
541 		musb_writew(epio, MUSB_RXCSR, csr);
542 	}
543 
544 	return done;
545 }
546 
547 /* we don't always need to reinit a given side of an endpoint...
548  * when we do, use tx/rx reinit routine and then construct a new CSR
549  * to address data toggle, NYET, and DMA or PIO.
550  *
551  * it's possible that driver bugs (especially for DMA) or aborting a
552  * transfer might have left the endpoint busier than it should be.
553  * the busy/not-empty tests are basically paranoia.
554  */
555 static void
556 musb_rx_reinit(struct musb *musb, struct musb_qh *qh, struct musb_hw_ep *ep)
557 {
558 	u16	csr;
559 
560 	/* NOTE:  we know the "rx" fifo reinit never triggers for ep0.
561 	 * That always uses tx_reinit since ep0 repurposes TX register
562 	 * offsets; the initial SETUP packet is also a kind of OUT.
563 	 */
564 
565 	/* if programmed for Tx, put it in RX mode */
566 	if (ep->is_shared_fifo) {
567 		csr = musb_readw(ep->regs, MUSB_TXCSR);
568 		if (csr & MUSB_TXCSR_MODE) {
569 			musb_h_tx_flush_fifo(ep);
570 			csr = musb_readw(ep->regs, MUSB_TXCSR);
571 			musb_writew(ep->regs, MUSB_TXCSR,
572 				    csr | MUSB_TXCSR_FRCDATATOG);
573 		}
574 
575 		/*
576 		 * Clear the MODE bit (and everything else) to enable Rx.
577 		 * NOTE: we mustn't clear the DMAMODE bit before DMAENAB.
578 		 */
579 		if (csr & MUSB_TXCSR_DMAMODE)
580 			musb_writew(ep->regs, MUSB_TXCSR, MUSB_TXCSR_DMAMODE);
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_write_rxfunaddr(ep->target_regs, qh->addr_reg);
596 		musb_write_rxhubaddr(ep->target_regs, qh->h_addr_reg);
597 		musb_write_rxhubport(ep->target_regs, qh->h_port_reg);
598 
599 	} else
600 		musb_writeb(musb->mregs, MUSB_FADDR, qh->addr_reg);
601 
602 	/* protocol/endpoint, interval/NAKlimit, i/o size */
603 	musb_writeb(ep->regs, MUSB_RXTYPE, qh->type_reg);
604 	musb_writeb(ep->regs, MUSB_RXINTERVAL, qh->intv_reg);
605 	/* NOTE: bulk combining rewrites high bits of maxpacket */
606 	/* Set RXMAXP with the FIFO size of the endpoint
607 	 * to disable double buffer mode.
608 	 */
609 	if (musb->double_buffer_not_ok)
610 		musb_writew(ep->regs, MUSB_RXMAXP, ep->max_packet_sz_rx);
611 	else
612 		musb_writew(ep->regs, MUSB_RXMAXP,
613 				qh->maxpacket | ((qh->hb_mult - 1) << 11));
614 
615 	ep->rx_reinit = 0;
616 }
617 
618 static bool musb_tx_dma_program(struct dma_controller *dma,
619 		struct musb_hw_ep *hw_ep, struct musb_qh *qh,
620 		struct urb *urb, u32 offset, u32 length)
621 {
622 	struct dma_channel	*channel = hw_ep->tx_channel;
623 	void __iomem		*epio = hw_ep->regs;
624 	u16			pkt_size = qh->maxpacket;
625 	u16			csr;
626 	u8			mode;
627 
628 #ifdef	CONFIG_USB_INVENTRA_DMA
629 	if (length > channel->max_len)
630 		length = channel->max_len;
631 
632 	csr = musb_readw(epio, MUSB_TXCSR);
633 	if (length > pkt_size) {
634 		mode = 1;
635 		csr |= MUSB_TXCSR_DMAMODE | MUSB_TXCSR_DMAENAB;
636 		/* autoset shouldn't be set in high bandwidth */
637 		if (qh->hb_mult == 1)
638 			csr |= MUSB_TXCSR_AUTOSET;
639 	} else {
640 		mode = 0;
641 		csr &= ~(MUSB_TXCSR_AUTOSET | MUSB_TXCSR_DMAMODE);
642 		csr |= MUSB_TXCSR_DMAENAB; /* against programmer's guide */
643 	}
644 	channel->desired_mode = mode;
645 	musb_writew(epio, MUSB_TXCSR, csr);
646 #else
647 	if (!is_cppi_enabled() && !tusb_dma_omap())
648 		return false;
649 
650 	channel->actual_len = 0;
651 
652 	/*
653 	 * TX uses "RNDIS" mode automatically but needs help
654 	 * to identify the zero-length-final-packet case.
655 	 */
656 	mode = (urb->transfer_flags & URB_ZERO_PACKET) ? 1 : 0;
657 #endif
658 
659 	qh->segsize = length;
660 
661 	/*
662 	 * Ensure the data reaches to main memory before starting
663 	 * DMA transfer
664 	 */
665 	wmb();
666 
667 	if (!dma->channel_program(channel, pkt_size, mode,
668 			urb->transfer_dma + offset, length)) {
669 		dma->channel_release(channel);
670 		hw_ep->tx_channel = NULL;
671 
672 		csr = musb_readw(epio, MUSB_TXCSR);
673 		csr &= ~(MUSB_TXCSR_AUTOSET | MUSB_TXCSR_DMAENAB);
674 		musb_writew(epio, MUSB_TXCSR, csr | MUSB_TXCSR_H_WZC_BITS);
675 		return false;
676 	}
677 	return true;
678 }
679 
680 /*
681  * Program an HDRC endpoint as per the given URB
682  * Context: irqs blocked, controller lock held
683  */
684 static void musb_ep_program(struct musb *musb, u8 epnum,
685 			struct urb *urb, int is_out,
686 			u8 *buf, u32 offset, u32 len)
687 {
688 	struct dma_controller	*dma_controller;
689 	struct dma_channel	*dma_channel;
690 	u8			dma_ok;
691 	void __iomem		*mbase = musb->mregs;
692 	struct musb_hw_ep	*hw_ep = musb->endpoints + epnum;
693 	void __iomem		*epio = hw_ep->regs;
694 	struct musb_qh		*qh = musb_ep_get_qh(hw_ep, !is_out);
695 	u16			packet_sz = qh->maxpacket;
696 
697 	dev_dbg(musb->controller, "%s hw%d urb %p spd%d dev%d ep%d%s "
698 				"h_addr%02x h_port%02x bytes %d\n",
699 			is_out ? "-->" : "<--",
700 			epnum, urb, urb->dev->speed,
701 			qh->addr_reg, qh->epnum, is_out ? "out" : "in",
702 			qh->h_addr_reg, qh->h_port_reg,
703 			len);
704 
705 	musb_ep_select(mbase, epnum);
706 
707 	/* candidate for DMA? */
708 	dma_controller = musb->dma_controller;
709 	if (is_dma_capable() && epnum && dma_controller) {
710 		dma_channel = is_out ? hw_ep->tx_channel : hw_ep->rx_channel;
711 		if (!dma_channel) {
712 			dma_channel = dma_controller->channel_alloc(
713 					dma_controller, hw_ep, is_out);
714 			if (is_out)
715 				hw_ep->tx_channel = dma_channel;
716 			else
717 				hw_ep->rx_channel = dma_channel;
718 		}
719 	} else
720 		dma_channel = NULL;
721 
722 	/* make sure we clear DMAEnab, autoSet bits from previous run */
723 
724 	/* OUT/transmit/EP0 or IN/receive? */
725 	if (is_out) {
726 		u16	csr;
727 		u16	int_txe;
728 		u16	load_count;
729 
730 		csr = musb_readw(epio, MUSB_TXCSR);
731 
732 		/* disable interrupt in case we flush */
733 		int_txe = musb_readw(mbase, MUSB_INTRTXE);
734 		musb_writew(mbase, MUSB_INTRTXE, int_txe & ~(1 << epnum));
735 
736 		/* general endpoint setup */
737 		if (epnum) {
738 			/* flush all old state, set default */
739 			musb_h_tx_flush_fifo(hw_ep);
740 
741 			/*
742 			 * We must not clear the DMAMODE bit before or in
743 			 * the same cycle with the DMAENAB bit, so we clear
744 			 * the latter first...
745 			 */
746 			csr &= ~(MUSB_TXCSR_H_NAKTIMEOUT
747 					| MUSB_TXCSR_AUTOSET
748 					| MUSB_TXCSR_DMAENAB
749 					| MUSB_TXCSR_FRCDATATOG
750 					| MUSB_TXCSR_H_RXSTALL
751 					| MUSB_TXCSR_H_ERROR
752 					| MUSB_TXCSR_TXPKTRDY
753 					);
754 			csr |= MUSB_TXCSR_MODE;
755 
756 			if (usb_gettoggle(urb->dev, qh->epnum, 1))
757 				csr |= MUSB_TXCSR_H_WR_DATATOGGLE
758 					| MUSB_TXCSR_H_DATATOGGLE;
759 			else
760 				csr |= MUSB_TXCSR_CLRDATATOG;
761 
762 			musb_writew(epio, MUSB_TXCSR, csr);
763 			/* REVISIT may need to clear FLUSHFIFO ... */
764 			csr &= ~MUSB_TXCSR_DMAMODE;
765 			musb_writew(epio, MUSB_TXCSR, csr);
766 			csr = musb_readw(epio, MUSB_TXCSR);
767 		} else {
768 			/* endpoint 0: just flush */
769 			musb_h_ep0_flush_fifo(hw_ep);
770 		}
771 
772 		/* target addr and (for multipoint) hub addr/port */
773 		if (musb->is_multipoint) {
774 			musb_write_txfunaddr(mbase, epnum, qh->addr_reg);
775 			musb_write_txhubaddr(mbase, epnum, qh->h_addr_reg);
776 			musb_write_txhubport(mbase, epnum, qh->h_port_reg);
777 /* FIXME if !epnum, do the same for RX ... */
778 		} else
779 			musb_writeb(mbase, MUSB_FADDR, qh->addr_reg);
780 
781 		/* protocol/endpoint/interval/NAKlimit */
782 		if (epnum) {
783 			musb_writeb(epio, MUSB_TXTYPE, qh->type_reg);
784 			if (musb->double_buffer_not_ok)
785 				musb_writew(epio, MUSB_TXMAXP,
786 						hw_ep->max_packet_sz_tx);
787 			else if (can_bulk_split(musb, qh->type))
788 				musb_writew(epio, MUSB_TXMAXP, packet_sz
789 					| ((hw_ep->max_packet_sz_tx /
790 						packet_sz) - 1) << 11);
791 			else
792 				musb_writew(epio, MUSB_TXMAXP,
793 						qh->maxpacket |
794 						((qh->hb_mult - 1) << 11));
795 			musb_writeb(epio, MUSB_TXINTERVAL, qh->intv_reg);
796 		} else {
797 			musb_writeb(epio, MUSB_NAKLIMIT0, qh->intv_reg);
798 			if (musb->is_multipoint)
799 				musb_writeb(epio, MUSB_TYPE0,
800 						qh->type_reg);
801 		}
802 
803 		if (can_bulk_split(musb, qh->type))
804 			load_count = min((u32) hw_ep->max_packet_sz_tx,
805 						len);
806 		else
807 			load_count = min((u32) packet_sz, len);
808 
809 		if (dma_channel && musb_tx_dma_program(dma_controller,
810 					hw_ep, qh, urb, offset, len))
811 			load_count = 0;
812 
813 		if (load_count) {
814 			/* PIO to load FIFO */
815 			qh->segsize = load_count;
816 			musb_write_fifo(hw_ep, load_count, buf);
817 		}
818 
819 		/* re-enable interrupt */
820 		musb_writew(mbase, MUSB_INTRTXE, int_txe);
821 
822 	/* IN/receive */
823 	} else {
824 		u16	csr;
825 
826 		if (hw_ep->rx_reinit) {
827 			musb_rx_reinit(musb, qh, hw_ep);
828 
829 			/* init new state: toggle and NYET, maybe DMA later */
830 			if (usb_gettoggle(urb->dev, qh->epnum, 0))
831 				csr = MUSB_RXCSR_H_WR_DATATOGGLE
832 					| MUSB_RXCSR_H_DATATOGGLE;
833 			else
834 				csr = 0;
835 			if (qh->type == USB_ENDPOINT_XFER_INT)
836 				csr |= MUSB_RXCSR_DISNYET;
837 
838 		} else {
839 			csr = musb_readw(hw_ep->regs, MUSB_RXCSR);
840 
841 			if (csr & (MUSB_RXCSR_RXPKTRDY
842 					| MUSB_RXCSR_DMAENAB
843 					| MUSB_RXCSR_H_REQPKT))
844 				ERR("broken !rx_reinit, ep%d csr %04x\n",
845 						hw_ep->epnum, csr);
846 
847 			/* scrub any stale state, leaving toggle alone */
848 			csr &= MUSB_RXCSR_DISNYET;
849 		}
850 
851 		/* kick things off */
852 
853 		if ((is_cppi_enabled() || tusb_dma_omap()) && dma_channel) {
854 			/* Candidate for DMA */
855 			dma_channel->actual_len = 0L;
856 			qh->segsize = len;
857 
858 			/* AUTOREQ is in a DMA register */
859 			musb_writew(hw_ep->regs, MUSB_RXCSR, csr);
860 			csr = musb_readw(hw_ep->regs, MUSB_RXCSR);
861 
862 			/*
863 			 * Unless caller treats short RX transfers as
864 			 * errors, we dare not queue multiple transfers.
865 			 */
866 			dma_ok = dma_controller->channel_program(dma_channel,
867 					packet_sz, !(urb->transfer_flags &
868 						     URB_SHORT_NOT_OK),
869 					urb->transfer_dma + offset,
870 					qh->segsize);
871 			if (!dma_ok) {
872 				dma_controller->channel_release(dma_channel);
873 				hw_ep->rx_channel = dma_channel = NULL;
874 			} else
875 				csr |= MUSB_RXCSR_DMAENAB;
876 		}
877 
878 		csr |= MUSB_RXCSR_H_REQPKT;
879 		dev_dbg(musb->controller, "RXCSR%d := %04x\n", epnum, csr);
880 		musb_writew(hw_ep->regs, MUSB_RXCSR, csr);
881 		csr = musb_readw(hw_ep->regs, MUSB_RXCSR);
882 	}
883 }
884 
885 
886 /*
887  * Service the default endpoint (ep0) as host.
888  * Return true until it's time to start the status stage.
889  */
890 static bool musb_h_ep0_continue(struct musb *musb, u16 len, struct urb *urb)
891 {
892 	bool			 more = false;
893 	u8			*fifo_dest = NULL;
894 	u16			fifo_count = 0;
895 	struct musb_hw_ep	*hw_ep = musb->control_ep;
896 	struct musb_qh		*qh = hw_ep->in_qh;
897 	struct usb_ctrlrequest	*request;
898 
899 	switch (musb->ep0_stage) {
900 	case MUSB_EP0_IN:
901 		fifo_dest = urb->transfer_buffer + urb->actual_length;
902 		fifo_count = min_t(size_t, len, urb->transfer_buffer_length -
903 				   urb->actual_length);
904 		if (fifo_count < len)
905 			urb->status = -EOVERFLOW;
906 
907 		musb_read_fifo(hw_ep, fifo_count, fifo_dest);
908 
909 		urb->actual_length += fifo_count;
910 		if (len < qh->maxpacket) {
911 			/* always terminate on short read; it's
912 			 * rarely reported as an error.
913 			 */
914 		} else if (urb->actual_length <
915 				urb->transfer_buffer_length)
916 			more = true;
917 		break;
918 	case MUSB_EP0_START:
919 		request = (struct usb_ctrlrequest *) urb->setup_packet;
920 
921 		if (!request->wLength) {
922 			dev_dbg(musb->controller, "start no-DATA\n");
923 			break;
924 		} else if (request->bRequestType & USB_DIR_IN) {
925 			dev_dbg(musb->controller, "start IN-DATA\n");
926 			musb->ep0_stage = MUSB_EP0_IN;
927 			more = true;
928 			break;
929 		} else {
930 			dev_dbg(musb->controller, "start OUT-DATA\n");
931 			musb->ep0_stage = MUSB_EP0_OUT;
932 			more = true;
933 		}
934 		/* FALLTHROUGH */
935 	case MUSB_EP0_OUT:
936 		fifo_count = min_t(size_t, qh->maxpacket,
937 				   urb->transfer_buffer_length -
938 				   urb->actual_length);
939 		if (fifo_count) {
940 			fifo_dest = (u8 *) (urb->transfer_buffer
941 					+ urb->actual_length);
942 			dev_dbg(musb->controller, "Sending %d byte%s to ep0 fifo %p\n",
943 					fifo_count,
944 					(fifo_count == 1) ? "" : "s",
945 					fifo_dest);
946 			musb_write_fifo(hw_ep, fifo_count, fifo_dest);
947 
948 			urb->actual_length += fifo_count;
949 			more = true;
950 		}
951 		break;
952 	default:
953 		ERR("bogus ep0 stage %d\n", musb->ep0_stage);
954 		break;
955 	}
956 
957 	return more;
958 }
959 
960 /*
961  * Handle default endpoint interrupt as host. Only called in IRQ time
962  * from musb_interrupt().
963  *
964  * called with controller irqlocked
965  */
966 irqreturn_t musb_h_ep0_irq(struct musb *musb)
967 {
968 	struct urb		*urb;
969 	u16			csr, len;
970 	int			status = 0;
971 	void __iomem		*mbase = musb->mregs;
972 	struct musb_hw_ep	*hw_ep = musb->control_ep;
973 	void __iomem		*epio = hw_ep->regs;
974 	struct musb_qh		*qh = hw_ep->in_qh;
975 	bool			complete = false;
976 	irqreturn_t		retval = IRQ_NONE;
977 
978 	/* ep0 only has one queue, "in" */
979 	urb = next_urb(qh);
980 
981 	musb_ep_select(mbase, 0);
982 	csr = musb_readw(epio, MUSB_CSR0);
983 	len = (csr & MUSB_CSR0_RXPKTRDY)
984 			? musb_readb(epio, MUSB_COUNT0)
985 			: 0;
986 
987 	dev_dbg(musb->controller, "<== csr0 %04x, qh %p, count %d, urb %p, stage %d\n",
988 		csr, qh, len, urb, musb->ep0_stage);
989 
990 	/* if we just did status stage, we are done */
991 	if (MUSB_EP0_STATUS == musb->ep0_stage) {
992 		retval = IRQ_HANDLED;
993 		complete = true;
994 	}
995 
996 	/* prepare status */
997 	if (csr & MUSB_CSR0_H_RXSTALL) {
998 		dev_dbg(musb->controller, "STALLING ENDPOINT\n");
999 		status = -EPIPE;
1000 
1001 	} else if (csr & MUSB_CSR0_H_ERROR) {
1002 		dev_dbg(musb->controller, "no response, csr0 %04x\n", csr);
1003 		status = -EPROTO;
1004 
1005 	} else if (csr & MUSB_CSR0_H_NAKTIMEOUT) {
1006 		dev_dbg(musb->controller, "control NAK timeout\n");
1007 
1008 		/* NOTE:  this code path would be a good place to PAUSE a
1009 		 * control transfer, if another one is queued, so that
1010 		 * ep0 is more likely to stay busy.  That's already done
1011 		 * for bulk RX transfers.
1012 		 *
1013 		 * if (qh->ring.next != &musb->control), then
1014 		 * we have a candidate... NAKing is *NOT* an error
1015 		 */
1016 		musb_writew(epio, MUSB_CSR0, 0);
1017 		retval = IRQ_HANDLED;
1018 	}
1019 
1020 	if (status) {
1021 		dev_dbg(musb->controller, "aborting\n");
1022 		retval = IRQ_HANDLED;
1023 		if (urb)
1024 			urb->status = status;
1025 		complete = true;
1026 
1027 		/* use the proper sequence to abort the transfer */
1028 		if (csr & MUSB_CSR0_H_REQPKT) {
1029 			csr &= ~MUSB_CSR0_H_REQPKT;
1030 			musb_writew(epio, MUSB_CSR0, csr);
1031 			csr &= ~MUSB_CSR0_H_NAKTIMEOUT;
1032 			musb_writew(epio, MUSB_CSR0, csr);
1033 		} else {
1034 			musb_h_ep0_flush_fifo(hw_ep);
1035 		}
1036 
1037 		musb_writeb(epio, MUSB_NAKLIMIT0, 0);
1038 
1039 		/* clear it */
1040 		musb_writew(epio, MUSB_CSR0, 0);
1041 	}
1042 
1043 	if (unlikely(!urb)) {
1044 		/* stop endpoint since we have no place for its data, this
1045 		 * SHOULD NEVER HAPPEN! */
1046 		ERR("no URB for end 0\n");
1047 
1048 		musb_h_ep0_flush_fifo(hw_ep);
1049 		goto done;
1050 	}
1051 
1052 	if (!complete) {
1053 		/* call common logic and prepare response */
1054 		if (musb_h_ep0_continue(musb, len, urb)) {
1055 			/* more packets required */
1056 			csr = (MUSB_EP0_IN == musb->ep0_stage)
1057 				?  MUSB_CSR0_H_REQPKT : MUSB_CSR0_TXPKTRDY;
1058 		} else {
1059 			/* data transfer complete; perform status phase */
1060 			if (usb_pipeout(urb->pipe)
1061 					|| !urb->transfer_buffer_length)
1062 				csr = MUSB_CSR0_H_STATUSPKT
1063 					| MUSB_CSR0_H_REQPKT;
1064 			else
1065 				csr = MUSB_CSR0_H_STATUSPKT
1066 					| MUSB_CSR0_TXPKTRDY;
1067 
1068 			/* flag status stage */
1069 			musb->ep0_stage = MUSB_EP0_STATUS;
1070 
1071 			dev_dbg(musb->controller, "ep0 STATUS, csr %04x\n", csr);
1072 
1073 		}
1074 		musb_writew(epio, MUSB_CSR0, csr);
1075 		retval = IRQ_HANDLED;
1076 	} else
1077 		musb->ep0_stage = MUSB_EP0_IDLE;
1078 
1079 	/* call completion handler if done */
1080 	if (complete)
1081 		musb_advance_schedule(musb, urb, hw_ep, 1);
1082 done:
1083 	return retval;
1084 }
1085 
1086 
1087 #ifdef CONFIG_USB_INVENTRA_DMA
1088 
1089 /* Host side TX (OUT) using Mentor DMA works as follows:
1090 	submit_urb ->
1091 		- if queue was empty, Program Endpoint
1092 		- ... which starts DMA to fifo in mode 1 or 0
1093 
1094 	DMA Isr (transfer complete) -> TxAvail()
1095 		- Stop DMA (~DmaEnab)	(<--- Alert ... currently happens
1096 					only in musb_cleanup_urb)
1097 		- TxPktRdy has to be set in mode 0 or for
1098 			short packets in mode 1.
1099 */
1100 
1101 #endif
1102 
1103 /* Service a Tx-Available or dma completion irq for the endpoint */
1104 void musb_host_tx(struct musb *musb, u8 epnum)
1105 {
1106 	int			pipe;
1107 	bool			done = false;
1108 	u16			tx_csr;
1109 	size_t			length = 0;
1110 	size_t			offset = 0;
1111 	struct musb_hw_ep	*hw_ep = musb->endpoints + epnum;
1112 	void __iomem		*epio = hw_ep->regs;
1113 	struct musb_qh		*qh = hw_ep->out_qh;
1114 	struct urb		*urb = next_urb(qh);
1115 	u32			status = 0;
1116 	void __iomem		*mbase = musb->mregs;
1117 	struct dma_channel	*dma;
1118 	bool			transfer_pending = false;
1119 
1120 	musb_ep_select(mbase, epnum);
1121 	tx_csr = musb_readw(epio, MUSB_TXCSR);
1122 
1123 	/* with CPPI, DMA sometimes triggers "extra" irqs */
1124 	if (!urb) {
1125 		dev_dbg(musb->controller, "extra TX%d ready, csr %04x\n", epnum, tx_csr);
1126 		return;
1127 	}
1128 
1129 	pipe = urb->pipe;
1130 	dma = is_dma_capable() ? hw_ep->tx_channel : NULL;
1131 	dev_dbg(musb->controller, "OUT/TX%d end, csr %04x%s\n", epnum, tx_csr,
1132 			dma ? ", dma" : "");
1133 
1134 	/* check for errors */
1135 	if (tx_csr & MUSB_TXCSR_H_RXSTALL) {
1136 		/* dma was disabled, fifo flushed */
1137 		dev_dbg(musb->controller, "TX end %d stall\n", epnum);
1138 
1139 		/* stall; record URB status */
1140 		status = -EPIPE;
1141 
1142 	} else if (tx_csr & MUSB_TXCSR_H_ERROR) {
1143 		/* (NON-ISO) dma was disabled, fifo flushed */
1144 		dev_dbg(musb->controller, "TX 3strikes on ep=%d\n", epnum);
1145 
1146 		status = -ETIMEDOUT;
1147 
1148 	} else if (tx_csr & MUSB_TXCSR_H_NAKTIMEOUT) {
1149 		dev_dbg(musb->controller, "TX end=%d device not responding\n", epnum);
1150 
1151 		/* NOTE:  this code path would be a good place to PAUSE a
1152 		 * transfer, if there's some other (nonperiodic) tx urb
1153 		 * that could use this fifo.  (dma complicates it...)
1154 		 * That's already done for bulk RX transfers.
1155 		 *
1156 		 * if (bulk && qh->ring.next != &musb->out_bulk), then
1157 		 * we have a candidate... NAKing is *NOT* an error
1158 		 */
1159 		musb_ep_select(mbase, epnum);
1160 		musb_writew(epio, MUSB_TXCSR,
1161 				MUSB_TXCSR_H_WZC_BITS
1162 				| MUSB_TXCSR_TXPKTRDY);
1163 		return;
1164 	}
1165 
1166 	if (status) {
1167 		if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1168 			dma->status = MUSB_DMA_STATUS_CORE_ABORT;
1169 			(void) musb->dma_controller->channel_abort(dma);
1170 		}
1171 
1172 		/* do the proper sequence to abort the transfer in the
1173 		 * usb core; the dma engine should already be stopped.
1174 		 */
1175 		musb_h_tx_flush_fifo(hw_ep);
1176 		tx_csr &= ~(MUSB_TXCSR_AUTOSET
1177 				| MUSB_TXCSR_DMAENAB
1178 				| MUSB_TXCSR_H_ERROR
1179 				| MUSB_TXCSR_H_RXSTALL
1180 				| MUSB_TXCSR_H_NAKTIMEOUT
1181 				);
1182 
1183 		musb_ep_select(mbase, epnum);
1184 		musb_writew(epio, MUSB_TXCSR, tx_csr);
1185 		/* REVISIT may need to clear FLUSHFIFO ... */
1186 		musb_writew(epio, MUSB_TXCSR, tx_csr);
1187 		musb_writeb(epio, MUSB_TXINTERVAL, 0);
1188 
1189 		done = true;
1190 	}
1191 
1192 	/* second cppi case */
1193 	if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1194 		dev_dbg(musb->controller, "extra TX%d ready, csr %04x\n", epnum, tx_csr);
1195 		return;
1196 	}
1197 
1198 	if (is_dma_capable() && dma && !status) {
1199 		/*
1200 		 * DMA has completed.  But if we're using DMA mode 1 (multi
1201 		 * packet DMA), we need a terminal TXPKTRDY interrupt before
1202 		 * we can consider this transfer completed, lest we trash
1203 		 * its last packet when writing the next URB's data.  So we
1204 		 * switch back to mode 0 to get that interrupt; we'll come
1205 		 * back here once it happens.
1206 		 */
1207 		if (tx_csr & MUSB_TXCSR_DMAMODE) {
1208 			/*
1209 			 * We shouldn't clear DMAMODE with DMAENAB set; so
1210 			 * clear them in a safe order.  That should be OK
1211 			 * once TXPKTRDY has been set (and I've never seen
1212 			 * it being 0 at this moment -- DMA interrupt latency
1213 			 * is significant) but if it hasn't been then we have
1214 			 * no choice but to stop being polite and ignore the
1215 			 * programmer's guide... :-)
1216 			 *
1217 			 * Note that we must write TXCSR with TXPKTRDY cleared
1218 			 * in order not to re-trigger the packet send (this bit
1219 			 * can't be cleared by CPU), and there's another caveat:
1220 			 * TXPKTRDY may be set shortly and then cleared in the
1221 			 * double-buffered FIFO mode, so we do an extra TXCSR
1222 			 * read for debouncing...
1223 			 */
1224 			tx_csr &= musb_readw(epio, MUSB_TXCSR);
1225 			if (tx_csr & MUSB_TXCSR_TXPKTRDY) {
1226 				tx_csr &= ~(MUSB_TXCSR_DMAENAB |
1227 					    MUSB_TXCSR_TXPKTRDY);
1228 				musb_writew(epio, MUSB_TXCSR,
1229 					    tx_csr | MUSB_TXCSR_H_WZC_BITS);
1230 			}
1231 			tx_csr &= ~(MUSB_TXCSR_DMAMODE |
1232 				    MUSB_TXCSR_TXPKTRDY);
1233 			musb_writew(epio, MUSB_TXCSR,
1234 				    tx_csr | MUSB_TXCSR_H_WZC_BITS);
1235 
1236 			/*
1237 			 * There is no guarantee that we'll get an interrupt
1238 			 * after clearing DMAMODE as we might have done this
1239 			 * too late (after TXPKTRDY was cleared by controller).
1240 			 * Re-read TXCSR as we have spoiled its previous value.
1241 			 */
1242 			tx_csr = musb_readw(epio, MUSB_TXCSR);
1243 		}
1244 
1245 		/*
1246 		 * We may get here from a DMA completion or TXPKTRDY interrupt.
1247 		 * In any case, we must check the FIFO status here and bail out
1248 		 * only if the FIFO still has data -- that should prevent the
1249 		 * "missed" TXPKTRDY interrupts and deal with double-buffered
1250 		 * FIFO mode too...
1251 		 */
1252 		if (tx_csr & (MUSB_TXCSR_FIFONOTEMPTY | MUSB_TXCSR_TXPKTRDY)) {
1253 			dev_dbg(musb->controller, "DMA complete but packet still in FIFO, "
1254 			    "CSR %04x\n", tx_csr);
1255 			return;
1256 		}
1257 	}
1258 
1259 	if (!status || dma || usb_pipeisoc(pipe)) {
1260 		if (dma)
1261 			length = dma->actual_len;
1262 		else
1263 			length = qh->segsize;
1264 		qh->offset += length;
1265 
1266 		if (usb_pipeisoc(pipe)) {
1267 			struct usb_iso_packet_descriptor	*d;
1268 
1269 			d = urb->iso_frame_desc + qh->iso_idx;
1270 			d->actual_length = length;
1271 			d->status = status;
1272 			if (++qh->iso_idx >= urb->number_of_packets) {
1273 				done = true;
1274 			} else {
1275 				d++;
1276 				offset = d->offset;
1277 				length = d->length;
1278 			}
1279 		} else if (dma && urb->transfer_buffer_length == qh->offset) {
1280 			done = true;
1281 		} else {
1282 			/* see if we need to send more data, or ZLP */
1283 			if (qh->segsize < qh->maxpacket)
1284 				done = true;
1285 			else if (qh->offset == urb->transfer_buffer_length
1286 					&& !(urb->transfer_flags
1287 						& URB_ZERO_PACKET))
1288 				done = true;
1289 			if (!done) {
1290 				offset = qh->offset;
1291 				length = urb->transfer_buffer_length - offset;
1292 				transfer_pending = true;
1293 			}
1294 		}
1295 	}
1296 
1297 	/* urb->status != -EINPROGRESS means request has been faulted,
1298 	 * so we must abort this transfer after cleanup
1299 	 */
1300 	if (urb->status != -EINPROGRESS) {
1301 		done = true;
1302 		if (status == 0)
1303 			status = urb->status;
1304 	}
1305 
1306 	if (done) {
1307 		/* set status */
1308 		urb->status = status;
1309 		urb->actual_length = qh->offset;
1310 		musb_advance_schedule(musb, urb, hw_ep, USB_DIR_OUT);
1311 		return;
1312 	} else if ((usb_pipeisoc(pipe) || transfer_pending) && dma) {
1313 		if (musb_tx_dma_program(musb->dma_controller, hw_ep, qh, urb,
1314 				offset, length)) {
1315 			if (is_cppi_enabled() || tusb_dma_omap())
1316 				musb_h_tx_dma_start(hw_ep);
1317 			return;
1318 		}
1319 	} else	if (tx_csr & MUSB_TXCSR_DMAENAB) {
1320 		dev_dbg(musb->controller, "not complete, but DMA enabled?\n");
1321 		return;
1322 	}
1323 
1324 	/*
1325 	 * PIO: start next packet in this URB.
1326 	 *
1327 	 * REVISIT: some docs say that when hw_ep->tx_double_buffered,
1328 	 * (and presumably, FIFO is not half-full) we should write *two*
1329 	 * packets before updating TXCSR; other docs disagree...
1330 	 */
1331 	if (length > qh->maxpacket)
1332 		length = qh->maxpacket;
1333 	/* Unmap the buffer so that CPU can use it */
1334 	usb_hcd_unmap_urb_for_dma(musb_to_hcd(musb), urb);
1335 	musb_write_fifo(hw_ep, length, urb->transfer_buffer + offset);
1336 	qh->segsize = length;
1337 
1338 	musb_ep_select(mbase, epnum);
1339 	musb_writew(epio, MUSB_TXCSR,
1340 			MUSB_TXCSR_H_WZC_BITS | MUSB_TXCSR_TXPKTRDY);
1341 }
1342 
1343 
1344 #ifdef CONFIG_USB_INVENTRA_DMA
1345 
1346 /* Host side RX (IN) using Mentor DMA works as follows:
1347 	submit_urb ->
1348 		- if queue was empty, ProgramEndpoint
1349 		- first IN token is sent out (by setting ReqPkt)
1350 	LinuxIsr -> RxReady()
1351 	/\	=> first packet is received
1352 	|	- Set in mode 0 (DmaEnab, ~ReqPkt)
1353 	|		-> DMA Isr (transfer complete) -> RxReady()
1354 	|		    - Ack receive (~RxPktRdy), turn off DMA (~DmaEnab)
1355 	|		    - if urb not complete, send next IN token (ReqPkt)
1356 	|			   |		else complete urb.
1357 	|			   |
1358 	---------------------------
1359  *
1360  * Nuances of mode 1:
1361  *	For short packets, no ack (+RxPktRdy) is sent automatically
1362  *	(even if AutoClear is ON)
1363  *	For full packets, ack (~RxPktRdy) and next IN token (+ReqPkt) is sent
1364  *	automatically => major problem, as collecting the next packet becomes
1365  *	difficult. Hence mode 1 is not used.
1366  *
1367  * REVISIT
1368  *	All we care about at this driver level is that
1369  *       (a) all URBs terminate with REQPKT cleared and fifo(s) empty;
1370  *       (b) termination conditions are: short RX, or buffer full;
1371  *       (c) fault modes include
1372  *           - iff URB_SHORT_NOT_OK, short RX status is -EREMOTEIO.
1373  *             (and that endpoint's dma queue stops immediately)
1374  *           - overflow (full, PLUS more bytes in the terminal packet)
1375  *
1376  *	So for example, usb-storage sets URB_SHORT_NOT_OK, and would
1377  *	thus be a great candidate for using mode 1 ... for all but the
1378  *	last packet of one URB's transfer.
1379  */
1380 
1381 #endif
1382 
1383 /* Schedule next QH from musb->in_bulk and move the current qh to
1384  * the end; avoids starvation for other endpoints.
1385  */
1386 static void musb_bulk_rx_nak_timeout(struct musb *musb, struct musb_hw_ep *ep)
1387 {
1388 	struct dma_channel	*dma;
1389 	struct urb		*urb;
1390 	void __iomem		*mbase = musb->mregs;
1391 	void __iomem		*epio = ep->regs;
1392 	struct musb_qh		*cur_qh, *next_qh;
1393 	u16			rx_csr;
1394 
1395 	musb_ep_select(mbase, ep->epnum);
1396 	dma = is_dma_capable() ? ep->rx_channel : NULL;
1397 
1398 	/* clear nak timeout bit */
1399 	rx_csr = musb_readw(epio, MUSB_RXCSR);
1400 	rx_csr |= MUSB_RXCSR_H_WZC_BITS;
1401 	rx_csr &= ~MUSB_RXCSR_DATAERROR;
1402 	musb_writew(epio, MUSB_RXCSR, rx_csr);
1403 
1404 	cur_qh = first_qh(&musb->in_bulk);
1405 	if (cur_qh) {
1406 		urb = next_urb(cur_qh);
1407 		if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1408 			dma->status = MUSB_DMA_STATUS_CORE_ABORT;
1409 			musb->dma_controller->channel_abort(dma);
1410 			urb->actual_length += dma->actual_len;
1411 			dma->actual_len = 0L;
1412 		}
1413 		musb_save_toggle(cur_qh, 1, urb);
1414 
1415 		/* move cur_qh to end of queue */
1416 		list_move_tail(&cur_qh->ring, &musb->in_bulk);
1417 
1418 		/* get the next qh from musb->in_bulk */
1419 		next_qh = first_qh(&musb->in_bulk);
1420 
1421 		/* set rx_reinit and schedule the next qh */
1422 		ep->rx_reinit = 1;
1423 		musb_start_urb(musb, 1, next_qh);
1424 	}
1425 }
1426 
1427 /*
1428  * Service an RX interrupt for the given IN endpoint; docs cover bulk, iso,
1429  * and high-bandwidth IN transfer cases.
1430  */
1431 void musb_host_rx(struct musb *musb, u8 epnum)
1432 {
1433 	struct urb		*urb;
1434 	struct musb_hw_ep	*hw_ep = musb->endpoints + epnum;
1435 	void __iomem		*epio = hw_ep->regs;
1436 	struct musb_qh		*qh = hw_ep->in_qh;
1437 	size_t			xfer_len;
1438 	void __iomem		*mbase = musb->mregs;
1439 	int			pipe;
1440 	u16			rx_csr, val;
1441 	bool			iso_err = false;
1442 	bool			done = false;
1443 	u32			status;
1444 	struct dma_channel	*dma;
1445 
1446 	musb_ep_select(mbase, epnum);
1447 
1448 	urb = next_urb(qh);
1449 	dma = is_dma_capable() ? hw_ep->rx_channel : NULL;
1450 	status = 0;
1451 	xfer_len = 0;
1452 
1453 	rx_csr = musb_readw(epio, MUSB_RXCSR);
1454 	val = rx_csr;
1455 
1456 	if (unlikely(!urb)) {
1457 		/* REVISIT -- THIS SHOULD NEVER HAPPEN ... but, at least
1458 		 * usbtest #11 (unlinks) triggers it regularly, sometimes
1459 		 * with fifo full.  (Only with DMA??)
1460 		 */
1461 		dev_dbg(musb->controller, "BOGUS RX%d ready, csr %04x, count %d\n", epnum, val,
1462 			musb_readw(epio, MUSB_RXCOUNT));
1463 		musb_h_flush_rxfifo(hw_ep, MUSB_RXCSR_CLRDATATOG);
1464 		return;
1465 	}
1466 
1467 	pipe = urb->pipe;
1468 
1469 	dev_dbg(musb->controller, "<== hw %d rxcsr %04x, urb actual %d (+dma %zu)\n",
1470 		epnum, rx_csr, urb->actual_length,
1471 		dma ? dma->actual_len : 0);
1472 
1473 	/* check for errors, concurrent stall & unlink is not really
1474 	 * handled yet! */
1475 	if (rx_csr & MUSB_RXCSR_H_RXSTALL) {
1476 		dev_dbg(musb->controller, "RX end %d STALL\n", epnum);
1477 
1478 		/* stall; record URB status */
1479 		status = -EPIPE;
1480 
1481 	} else if (rx_csr & MUSB_RXCSR_H_ERROR) {
1482 		dev_dbg(musb->controller, "end %d RX proto error\n", epnum);
1483 
1484 		status = -EPROTO;
1485 		musb_writeb(epio, MUSB_RXINTERVAL, 0);
1486 
1487 	} else if (rx_csr & MUSB_RXCSR_DATAERROR) {
1488 
1489 		if (USB_ENDPOINT_XFER_ISOC != qh->type) {
1490 			dev_dbg(musb->controller, "RX end %d NAK timeout\n", epnum);
1491 
1492 			/* NOTE: NAKing is *NOT* an error, so we want to
1493 			 * continue.  Except ... if there's a request for
1494 			 * another QH, use that instead of starving it.
1495 			 *
1496 			 * Devices like Ethernet and serial adapters keep
1497 			 * reads posted at all times, which will starve
1498 			 * other devices without this logic.
1499 			 */
1500 			if (usb_pipebulk(urb->pipe)
1501 					&& qh->mux == 1
1502 					&& !list_is_singular(&musb->in_bulk)) {
1503 				musb_bulk_rx_nak_timeout(musb, hw_ep);
1504 				return;
1505 			}
1506 			musb_ep_select(mbase, epnum);
1507 			rx_csr |= MUSB_RXCSR_H_WZC_BITS;
1508 			rx_csr &= ~MUSB_RXCSR_DATAERROR;
1509 			musb_writew(epio, MUSB_RXCSR, rx_csr);
1510 
1511 			goto finish;
1512 		} else {
1513 			dev_dbg(musb->controller, "RX end %d ISO data error\n", epnum);
1514 			/* packet error reported later */
1515 			iso_err = true;
1516 		}
1517 	} else if (rx_csr & MUSB_RXCSR_INCOMPRX) {
1518 		dev_dbg(musb->controller, "end %d high bandwidth incomplete ISO packet RX\n",
1519 				epnum);
1520 		status = -EPROTO;
1521 	}
1522 
1523 	/* faults abort the transfer */
1524 	if (status) {
1525 		/* clean up dma and collect transfer count */
1526 		if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1527 			dma->status = MUSB_DMA_STATUS_CORE_ABORT;
1528 			(void) musb->dma_controller->channel_abort(dma);
1529 			xfer_len = dma->actual_len;
1530 		}
1531 		musb_h_flush_rxfifo(hw_ep, MUSB_RXCSR_CLRDATATOG);
1532 		musb_writeb(epio, MUSB_RXINTERVAL, 0);
1533 		done = true;
1534 		goto finish;
1535 	}
1536 
1537 	if (unlikely(dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY)) {
1538 		/* SHOULD NEVER HAPPEN ... but at least DaVinci has done it */
1539 		ERR("RX%d dma busy, csr %04x\n", epnum, rx_csr);
1540 		goto finish;
1541 	}
1542 
1543 	/* thorough shutdown for now ... given more precise fault handling
1544 	 * and better queueing support, we might keep a DMA pipeline going
1545 	 * while processing this irq for earlier completions.
1546 	 */
1547 
1548 	/* FIXME this is _way_ too much in-line logic for Mentor DMA */
1549 
1550 #ifndef CONFIG_USB_INVENTRA_DMA
1551 	if (rx_csr & MUSB_RXCSR_H_REQPKT)  {
1552 		/* REVISIT this happened for a while on some short reads...
1553 		 * the cleanup still needs investigation... looks bad...
1554 		 * and also duplicates dma cleanup code above ... plus,
1555 		 * shouldn't this be the "half full" double buffer case?
1556 		 */
1557 		if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1558 			dma->status = MUSB_DMA_STATUS_CORE_ABORT;
1559 			(void) musb->dma_controller->channel_abort(dma);
1560 			xfer_len = dma->actual_len;
1561 			done = true;
1562 		}
1563 
1564 		dev_dbg(musb->controller, "RXCSR%d %04x, reqpkt, len %zu%s\n", epnum, rx_csr,
1565 				xfer_len, dma ? ", dma" : "");
1566 		rx_csr &= ~MUSB_RXCSR_H_REQPKT;
1567 
1568 		musb_ep_select(mbase, epnum);
1569 		musb_writew(epio, MUSB_RXCSR,
1570 				MUSB_RXCSR_H_WZC_BITS | rx_csr);
1571 	}
1572 #endif
1573 	if (dma && (rx_csr & MUSB_RXCSR_DMAENAB)) {
1574 		xfer_len = dma->actual_len;
1575 
1576 		val &= ~(MUSB_RXCSR_DMAENAB
1577 			| MUSB_RXCSR_H_AUTOREQ
1578 			| MUSB_RXCSR_AUTOCLEAR
1579 			| MUSB_RXCSR_RXPKTRDY);
1580 		musb_writew(hw_ep->regs, MUSB_RXCSR, val);
1581 
1582 #ifdef CONFIG_USB_INVENTRA_DMA
1583 		if (usb_pipeisoc(pipe)) {
1584 			struct usb_iso_packet_descriptor *d;
1585 
1586 			d = urb->iso_frame_desc + qh->iso_idx;
1587 			d->actual_length = xfer_len;
1588 
1589 			/* even if there was an error, we did the dma
1590 			 * for iso_frame_desc->length
1591 			 */
1592 			if (d->status != -EILSEQ && d->status != -EOVERFLOW)
1593 				d->status = 0;
1594 
1595 			if (++qh->iso_idx >= urb->number_of_packets)
1596 				done = true;
1597 			else
1598 				done = false;
1599 
1600 		} else  {
1601 		/* done if urb buffer is full or short packet is recd */
1602 		done = (urb->actual_length + xfer_len >=
1603 				urb->transfer_buffer_length
1604 			|| dma->actual_len < qh->maxpacket);
1605 		}
1606 
1607 		/* send IN token for next packet, without AUTOREQ */
1608 		if (!done) {
1609 			val |= MUSB_RXCSR_H_REQPKT;
1610 			musb_writew(epio, MUSB_RXCSR,
1611 				MUSB_RXCSR_H_WZC_BITS | val);
1612 		}
1613 
1614 		dev_dbg(musb->controller, "ep %d dma %s, rxcsr %04x, rxcount %d\n", epnum,
1615 			done ? "off" : "reset",
1616 			musb_readw(epio, MUSB_RXCSR),
1617 			musb_readw(epio, MUSB_RXCOUNT));
1618 #else
1619 		done = true;
1620 #endif
1621 	} else if (urb->status == -EINPROGRESS) {
1622 		/* if no errors, be sure a packet is ready for unloading */
1623 		if (unlikely(!(rx_csr & MUSB_RXCSR_RXPKTRDY))) {
1624 			status = -EPROTO;
1625 			ERR("Rx interrupt with no errors or packet!\n");
1626 
1627 			/* FIXME this is another "SHOULD NEVER HAPPEN" */
1628 
1629 /* SCRUB (RX) */
1630 			/* do the proper sequence to abort the transfer */
1631 			musb_ep_select(mbase, epnum);
1632 			val &= ~MUSB_RXCSR_H_REQPKT;
1633 			musb_writew(epio, MUSB_RXCSR, val);
1634 			goto finish;
1635 		}
1636 
1637 		/* we are expecting IN packets */
1638 #ifdef CONFIG_USB_INVENTRA_DMA
1639 		if (dma) {
1640 			struct dma_controller	*c;
1641 			u16			rx_count;
1642 			int			ret, length;
1643 			dma_addr_t		buf;
1644 
1645 			rx_count = musb_readw(epio, MUSB_RXCOUNT);
1646 
1647 			dev_dbg(musb->controller, "RX%d count %d, buffer 0x%x len %d/%d\n",
1648 					epnum, rx_count,
1649 					urb->transfer_dma
1650 						+ urb->actual_length,
1651 					qh->offset,
1652 					urb->transfer_buffer_length);
1653 
1654 			c = musb->dma_controller;
1655 
1656 			if (usb_pipeisoc(pipe)) {
1657 				int d_status = 0;
1658 				struct usb_iso_packet_descriptor *d;
1659 
1660 				d = urb->iso_frame_desc + qh->iso_idx;
1661 
1662 				if (iso_err) {
1663 					d_status = -EILSEQ;
1664 					urb->error_count++;
1665 				}
1666 				if (rx_count > d->length) {
1667 					if (d_status == 0) {
1668 						d_status = -EOVERFLOW;
1669 						urb->error_count++;
1670 					}
1671 					dev_dbg(musb->controller, "** OVERFLOW %d into %d\n",\
1672 					    rx_count, d->length);
1673 
1674 					length = d->length;
1675 				} else
1676 					length = rx_count;
1677 				d->status = d_status;
1678 				buf = urb->transfer_dma + d->offset;
1679 			} else {
1680 				length = rx_count;
1681 				buf = urb->transfer_dma +
1682 						urb->actual_length;
1683 			}
1684 
1685 			dma->desired_mode = 0;
1686 #ifdef USE_MODE1
1687 			/* because of the issue below, mode 1 will
1688 			 * only rarely behave with correct semantics.
1689 			 */
1690 			if ((urb->transfer_flags &
1691 						URB_SHORT_NOT_OK)
1692 				&& (urb->transfer_buffer_length -
1693 						urb->actual_length)
1694 					> qh->maxpacket)
1695 				dma->desired_mode = 1;
1696 			if (rx_count < hw_ep->max_packet_sz_rx) {
1697 				length = rx_count;
1698 				dma->desired_mode = 0;
1699 			} else {
1700 				length = urb->transfer_buffer_length;
1701 			}
1702 #endif
1703 
1704 /* Disadvantage of using mode 1:
1705  *	It's basically usable only for mass storage class; essentially all
1706  *	other protocols also terminate transfers on short packets.
1707  *
1708  * Details:
1709  *	An extra IN token is sent at the end of the transfer (due to AUTOREQ)
1710  *	If you try to use mode 1 for (transfer_buffer_length - 512), and try
1711  *	to use the extra IN token to grab the last packet using mode 0, then
1712  *	the problem is that you cannot be sure when the device will send the
1713  *	last packet and RxPktRdy set. Sometimes the packet is recd too soon
1714  *	such that it gets lost when RxCSR is re-set at the end of the mode 1
1715  *	transfer, while sometimes it is recd just a little late so that if you
1716  *	try to configure for mode 0 soon after the mode 1 transfer is
1717  *	completed, you will find rxcount 0. Okay, so you might think why not
1718  *	wait for an interrupt when the pkt is recd. Well, you won't get any!
1719  */
1720 
1721 			val = musb_readw(epio, MUSB_RXCSR);
1722 			val &= ~MUSB_RXCSR_H_REQPKT;
1723 
1724 			if (dma->desired_mode == 0)
1725 				val &= ~MUSB_RXCSR_H_AUTOREQ;
1726 			else
1727 				val |= MUSB_RXCSR_H_AUTOREQ;
1728 			val |= MUSB_RXCSR_DMAENAB;
1729 
1730 			/* autoclear shouldn't be set in high bandwidth */
1731 			if (qh->hb_mult == 1)
1732 				val |= MUSB_RXCSR_AUTOCLEAR;
1733 
1734 			musb_writew(epio, MUSB_RXCSR,
1735 				MUSB_RXCSR_H_WZC_BITS | val);
1736 
1737 			/* REVISIT if when actual_length != 0,
1738 			 * transfer_buffer_length needs to be
1739 			 * adjusted first...
1740 			 */
1741 			ret = c->channel_program(
1742 				dma, qh->maxpacket,
1743 				dma->desired_mode, buf, length);
1744 
1745 			if (!ret) {
1746 				c->channel_release(dma);
1747 				hw_ep->rx_channel = NULL;
1748 				dma = NULL;
1749 				val = musb_readw(epio, MUSB_RXCSR);
1750 				val &= ~(MUSB_RXCSR_DMAENAB
1751 					| MUSB_RXCSR_H_AUTOREQ
1752 					| MUSB_RXCSR_AUTOCLEAR);
1753 				musb_writew(epio, MUSB_RXCSR, val);
1754 			}
1755 		}
1756 #endif	/* Mentor DMA */
1757 
1758 		if (!dma) {
1759 			/* Unmap the buffer so that CPU can use it */
1760 			usb_hcd_unmap_urb_for_dma(musb_to_hcd(musb), urb);
1761 			done = musb_host_packet_rx(musb, urb,
1762 					epnum, iso_err);
1763 			dev_dbg(musb->controller, "read %spacket\n", done ? "last " : "");
1764 		}
1765 	}
1766 
1767 finish:
1768 	urb->actual_length += xfer_len;
1769 	qh->offset += xfer_len;
1770 	if (done) {
1771 		if (urb->status == -EINPROGRESS)
1772 			urb->status = status;
1773 		musb_advance_schedule(musb, urb, hw_ep, USB_DIR_IN);
1774 	}
1775 }
1776 
1777 /* schedule nodes correspond to peripheral endpoints, like an OHCI QH.
1778  * the software schedule associates multiple such nodes with a given
1779  * host side hardware endpoint + direction; scheduling may activate
1780  * that hardware endpoint.
1781  */
1782 static int musb_schedule(
1783 	struct musb		*musb,
1784 	struct musb_qh		*qh,
1785 	int			is_in)
1786 {
1787 	int			idle;
1788 	int			best_diff;
1789 	int			best_end, epnum;
1790 	struct musb_hw_ep	*hw_ep = NULL;
1791 	struct list_head	*head = NULL;
1792 	u8			toggle;
1793 	u8			txtype;
1794 	struct urb		*urb = next_urb(qh);
1795 
1796 	/* use fixed hardware for control and bulk */
1797 	if (qh->type == USB_ENDPOINT_XFER_CONTROL) {
1798 		head = &musb->control;
1799 		hw_ep = musb->control_ep;
1800 		goto success;
1801 	}
1802 
1803 	/* else, periodic transfers get muxed to other endpoints */
1804 
1805 	/*
1806 	 * We know this qh hasn't been scheduled, so all we need to do
1807 	 * is choose which hardware endpoint to put it on ...
1808 	 *
1809 	 * REVISIT what we really want here is a regular schedule tree
1810 	 * like e.g. OHCI uses.
1811 	 */
1812 	best_diff = 4096;
1813 	best_end = -1;
1814 
1815 	for (epnum = 1, hw_ep = musb->endpoints + 1;
1816 			epnum < musb->nr_endpoints;
1817 			epnum++, hw_ep++) {
1818 		int	diff;
1819 
1820 		if (musb_ep_get_qh(hw_ep, is_in) != NULL)
1821 			continue;
1822 
1823 		if (hw_ep == musb->bulk_ep)
1824 			continue;
1825 
1826 		if (is_in)
1827 			diff = hw_ep->max_packet_sz_rx;
1828 		else
1829 			diff = hw_ep->max_packet_sz_tx;
1830 		diff -= (qh->maxpacket * qh->hb_mult);
1831 
1832 		if (diff >= 0 && best_diff > diff) {
1833 
1834 			/*
1835 			 * Mentor controller has a bug in that if we schedule
1836 			 * a BULK Tx transfer on an endpoint that had earlier
1837 			 * handled ISOC then the BULK transfer has to start on
1838 			 * a zero toggle.  If the BULK transfer starts on a 1
1839 			 * toggle then this transfer will fail as the mentor
1840 			 * controller starts the Bulk transfer on a 0 toggle
1841 			 * irrespective of the programming of the toggle bits
1842 			 * in the TXCSR register.  Check for this condition
1843 			 * while allocating the EP for a Tx Bulk transfer.  If
1844 			 * so skip this EP.
1845 			 */
1846 			hw_ep = musb->endpoints + epnum;
1847 			toggle = usb_gettoggle(urb->dev, qh->epnum, !is_in);
1848 			txtype = (musb_readb(hw_ep->regs, MUSB_TXTYPE)
1849 					>> 4) & 0x3;
1850 			if (!is_in && (qh->type == USB_ENDPOINT_XFER_BULK) &&
1851 				toggle && (txtype == USB_ENDPOINT_XFER_ISOC))
1852 				continue;
1853 
1854 			best_diff = diff;
1855 			best_end = epnum;
1856 		}
1857 	}
1858 	/* use bulk reserved ep1 if no other ep is free */
1859 	if (best_end < 0 && qh->type == USB_ENDPOINT_XFER_BULK) {
1860 		hw_ep = musb->bulk_ep;
1861 		if (is_in)
1862 			head = &musb->in_bulk;
1863 		else
1864 			head = &musb->out_bulk;
1865 
1866 		/* Enable bulk RX NAK timeout scheme when bulk requests are
1867 		 * multiplexed.  This scheme doen't work in high speed to full
1868 		 * speed scenario as NAK interrupts are not coming from a
1869 		 * full speed device connected to a high speed device.
1870 		 * NAK timeout interval is 8 (128 uframe or 16ms) for HS and
1871 		 * 4 (8 frame or 8ms) for FS device.
1872 		 */
1873 		if (is_in && qh->dev)
1874 			qh->intv_reg =
1875 				(USB_SPEED_HIGH == qh->dev->speed) ? 8 : 4;
1876 		goto success;
1877 	} else if (best_end < 0) {
1878 		return -ENOSPC;
1879 	}
1880 
1881 	idle = 1;
1882 	qh->mux = 0;
1883 	hw_ep = musb->endpoints + best_end;
1884 	dev_dbg(musb->controller, "qh %p periodic slot %d\n", qh, best_end);
1885 success:
1886 	if (head) {
1887 		idle = list_empty(head);
1888 		list_add_tail(&qh->ring, head);
1889 		qh->mux = 1;
1890 	}
1891 	qh->hw_ep = hw_ep;
1892 	qh->hep->hcpriv = qh;
1893 	if (idle)
1894 		musb_start_urb(musb, is_in, qh);
1895 	return 0;
1896 }
1897 
1898 static int musb_urb_enqueue(
1899 	struct usb_hcd			*hcd,
1900 	struct urb			*urb,
1901 	gfp_t				mem_flags)
1902 {
1903 	unsigned long			flags;
1904 	struct musb			*musb = hcd_to_musb(hcd);
1905 	struct usb_host_endpoint	*hep = urb->ep;
1906 	struct musb_qh			*qh;
1907 	struct usb_endpoint_descriptor	*epd = &hep->desc;
1908 	int				ret;
1909 	unsigned			type_reg;
1910 	unsigned			interval;
1911 
1912 	/* host role must be active */
1913 	if (!is_host_active(musb) || !musb->is_active)
1914 		return -ENODEV;
1915 
1916 	spin_lock_irqsave(&musb->lock, flags);
1917 	ret = usb_hcd_link_urb_to_ep(hcd, urb);
1918 	qh = ret ? NULL : hep->hcpriv;
1919 	if (qh)
1920 		urb->hcpriv = qh;
1921 	spin_unlock_irqrestore(&musb->lock, flags);
1922 
1923 	/* DMA mapping was already done, if needed, and this urb is on
1924 	 * hep->urb_list now ... so we're done, unless hep wasn't yet
1925 	 * scheduled onto a live qh.
1926 	 *
1927 	 * REVISIT best to keep hep->hcpriv valid until the endpoint gets
1928 	 * disabled, testing for empty qh->ring and avoiding qh setup costs
1929 	 * except for the first urb queued after a config change.
1930 	 */
1931 	if (qh || ret)
1932 		return ret;
1933 
1934 	/* Allocate and initialize qh, minimizing the work done each time
1935 	 * hw_ep gets reprogrammed, or with irqs blocked.  Then schedule it.
1936 	 *
1937 	 * REVISIT consider a dedicated qh kmem_cache, so it's harder
1938 	 * for bugs in other kernel code to break this driver...
1939 	 */
1940 	qh = kzalloc(sizeof *qh, mem_flags);
1941 	if (!qh) {
1942 		spin_lock_irqsave(&musb->lock, flags);
1943 		usb_hcd_unlink_urb_from_ep(hcd, urb);
1944 		spin_unlock_irqrestore(&musb->lock, flags);
1945 		return -ENOMEM;
1946 	}
1947 
1948 	qh->hep = hep;
1949 	qh->dev = urb->dev;
1950 	INIT_LIST_HEAD(&qh->ring);
1951 	qh->is_ready = 1;
1952 
1953 	qh->maxpacket = usb_endpoint_maxp(epd);
1954 	qh->type = usb_endpoint_type(epd);
1955 
1956 	/* Bits 11 & 12 of wMaxPacketSize encode high bandwidth multiplier.
1957 	 * Some musb cores don't support high bandwidth ISO transfers; and
1958 	 * we don't (yet!) support high bandwidth interrupt transfers.
1959 	 */
1960 	qh->hb_mult = 1 + ((qh->maxpacket >> 11) & 0x03);
1961 	if (qh->hb_mult > 1) {
1962 		int ok = (qh->type == USB_ENDPOINT_XFER_ISOC);
1963 
1964 		if (ok)
1965 			ok = (usb_pipein(urb->pipe) && musb->hb_iso_rx)
1966 				|| (usb_pipeout(urb->pipe) && musb->hb_iso_tx);
1967 		if (!ok) {
1968 			ret = -EMSGSIZE;
1969 			goto done;
1970 		}
1971 		qh->maxpacket &= 0x7ff;
1972 	}
1973 
1974 	qh->epnum = usb_endpoint_num(epd);
1975 
1976 	/* NOTE: urb->dev->devnum is wrong during SET_ADDRESS */
1977 	qh->addr_reg = (u8) usb_pipedevice(urb->pipe);
1978 
1979 	/* precompute rxtype/txtype/type0 register */
1980 	type_reg = (qh->type << 4) | qh->epnum;
1981 	switch (urb->dev->speed) {
1982 	case USB_SPEED_LOW:
1983 		type_reg |= 0xc0;
1984 		break;
1985 	case USB_SPEED_FULL:
1986 		type_reg |= 0x80;
1987 		break;
1988 	default:
1989 		type_reg |= 0x40;
1990 	}
1991 	qh->type_reg = type_reg;
1992 
1993 	/* Precompute RXINTERVAL/TXINTERVAL register */
1994 	switch (qh->type) {
1995 	case USB_ENDPOINT_XFER_INT:
1996 		/*
1997 		 * Full/low speeds use the  linear encoding,
1998 		 * high speed uses the logarithmic encoding.
1999 		 */
2000 		if (urb->dev->speed <= USB_SPEED_FULL) {
2001 			interval = max_t(u8, epd->bInterval, 1);
2002 			break;
2003 		}
2004 		/* FALLTHROUGH */
2005 	case USB_ENDPOINT_XFER_ISOC:
2006 		/* ISO always uses logarithmic encoding */
2007 		interval = min_t(u8, epd->bInterval, 16);
2008 		break;
2009 	default:
2010 		/* REVISIT we actually want to use NAK limits, hinting to the
2011 		 * transfer scheduling logic to try some other qh, e.g. try
2012 		 * for 2 msec first:
2013 		 *
2014 		 * interval = (USB_SPEED_HIGH == urb->dev->speed) ? 16 : 2;
2015 		 *
2016 		 * The downside of disabling this is that transfer scheduling
2017 		 * gets VERY unfair for nonperiodic transfers; a misbehaving
2018 		 * peripheral could make that hurt.  That's perfectly normal
2019 		 * for reads from network or serial adapters ... so we have
2020 		 * partial NAKlimit support for bulk RX.
2021 		 *
2022 		 * The upside of disabling it is simpler transfer scheduling.
2023 		 */
2024 		interval = 0;
2025 	}
2026 	qh->intv_reg = interval;
2027 
2028 	/* precompute addressing for external hub/tt ports */
2029 	if (musb->is_multipoint) {
2030 		struct usb_device	*parent = urb->dev->parent;
2031 
2032 		if (parent != hcd->self.root_hub) {
2033 			qh->h_addr_reg = (u8) parent->devnum;
2034 
2035 			/* set up tt info if needed */
2036 			if (urb->dev->tt) {
2037 				qh->h_port_reg = (u8) urb->dev->ttport;
2038 				if (urb->dev->tt->hub)
2039 					qh->h_addr_reg =
2040 						(u8) urb->dev->tt->hub->devnum;
2041 				if (urb->dev->tt->multi)
2042 					qh->h_addr_reg |= 0x80;
2043 			}
2044 		}
2045 	}
2046 
2047 	/* invariant: hep->hcpriv is null OR the qh that's already scheduled.
2048 	 * until we get real dma queues (with an entry for each urb/buffer),
2049 	 * we only have work to do in the former case.
2050 	 */
2051 	spin_lock_irqsave(&musb->lock, flags);
2052 	if (hep->hcpriv) {
2053 		/* some concurrent activity submitted another urb to hep...
2054 		 * odd, rare, error prone, but legal.
2055 		 */
2056 		kfree(qh);
2057 		qh = NULL;
2058 		ret = 0;
2059 	} else
2060 		ret = musb_schedule(musb, qh,
2061 				epd->bEndpointAddress & USB_ENDPOINT_DIR_MASK);
2062 
2063 	if (ret == 0) {
2064 		urb->hcpriv = qh;
2065 		/* FIXME set urb->start_frame for iso/intr, it's tested in
2066 		 * musb_start_urb(), but otherwise only konicawc cares ...
2067 		 */
2068 	}
2069 	spin_unlock_irqrestore(&musb->lock, flags);
2070 
2071 done:
2072 	if (ret != 0) {
2073 		spin_lock_irqsave(&musb->lock, flags);
2074 		usb_hcd_unlink_urb_from_ep(hcd, urb);
2075 		spin_unlock_irqrestore(&musb->lock, flags);
2076 		kfree(qh);
2077 	}
2078 	return ret;
2079 }
2080 
2081 
2082 /*
2083  * abort a transfer that's at the head of a hardware queue.
2084  * called with controller locked, irqs blocked
2085  * that hardware queue advances to the next transfer, unless prevented
2086  */
2087 static int musb_cleanup_urb(struct urb *urb, struct musb_qh *qh)
2088 {
2089 	struct musb_hw_ep	*ep = qh->hw_ep;
2090 	struct musb		*musb = ep->musb;
2091 	void __iomem		*epio = ep->regs;
2092 	unsigned		hw_end = ep->epnum;
2093 	void __iomem		*regs = ep->musb->mregs;
2094 	int			is_in = usb_pipein(urb->pipe);
2095 	int			status = 0;
2096 	u16			csr;
2097 
2098 	musb_ep_select(regs, hw_end);
2099 
2100 	if (is_dma_capable()) {
2101 		struct dma_channel	*dma;
2102 
2103 		dma = is_in ? ep->rx_channel : ep->tx_channel;
2104 		if (dma) {
2105 			status = ep->musb->dma_controller->channel_abort(dma);
2106 			dev_dbg(musb->controller,
2107 				"abort %cX%d DMA for urb %p --> %d\n",
2108 				is_in ? 'R' : 'T', ep->epnum,
2109 				urb, status);
2110 			urb->actual_length += dma->actual_len;
2111 		}
2112 	}
2113 
2114 	/* turn off DMA requests, discard state, stop polling ... */
2115 	if (ep->epnum && is_in) {
2116 		/* giveback saves bulk toggle */
2117 		csr = musb_h_flush_rxfifo(ep, 0);
2118 
2119 		/* REVISIT we still get an irq; should likely clear the
2120 		 * endpoint's irq status here to avoid bogus irqs.
2121 		 * clearing that status is platform-specific...
2122 		 */
2123 	} else if (ep->epnum) {
2124 		musb_h_tx_flush_fifo(ep);
2125 		csr = musb_readw(epio, MUSB_TXCSR);
2126 		csr &= ~(MUSB_TXCSR_AUTOSET
2127 			| MUSB_TXCSR_DMAENAB
2128 			| MUSB_TXCSR_H_RXSTALL
2129 			| MUSB_TXCSR_H_NAKTIMEOUT
2130 			| MUSB_TXCSR_H_ERROR
2131 			| MUSB_TXCSR_TXPKTRDY);
2132 		musb_writew(epio, MUSB_TXCSR, csr);
2133 		/* REVISIT may need to clear FLUSHFIFO ... */
2134 		musb_writew(epio, MUSB_TXCSR, csr);
2135 		/* flush cpu writebuffer */
2136 		csr = musb_readw(epio, MUSB_TXCSR);
2137 	} else  {
2138 		musb_h_ep0_flush_fifo(ep);
2139 	}
2140 	if (status == 0)
2141 		musb_advance_schedule(ep->musb, urb, ep, is_in);
2142 	return status;
2143 }
2144 
2145 static int musb_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
2146 {
2147 	struct musb		*musb = hcd_to_musb(hcd);
2148 	struct musb_qh		*qh;
2149 	unsigned long		flags;
2150 	int			is_in  = usb_pipein(urb->pipe);
2151 	int			ret;
2152 
2153 	dev_dbg(musb->controller, "urb=%p, dev%d ep%d%s\n", urb,
2154 			usb_pipedevice(urb->pipe),
2155 			usb_pipeendpoint(urb->pipe),
2156 			is_in ? "in" : "out");
2157 
2158 	spin_lock_irqsave(&musb->lock, flags);
2159 	ret = usb_hcd_check_unlink_urb(hcd, urb, status);
2160 	if (ret)
2161 		goto done;
2162 
2163 	qh = urb->hcpriv;
2164 	if (!qh)
2165 		goto done;
2166 
2167 	/*
2168 	 * Any URB not actively programmed into endpoint hardware can be
2169 	 * immediately given back; that's any URB not at the head of an
2170 	 * endpoint queue, unless someday we get real DMA queues.  And even
2171 	 * if it's at the head, it might not be known to the hardware...
2172 	 *
2173 	 * Otherwise abort current transfer, pending DMA, etc.; urb->status
2174 	 * has already been updated.  This is a synchronous abort; it'd be
2175 	 * OK to hold off until after some IRQ, though.
2176 	 *
2177 	 * NOTE: qh is invalid unless !list_empty(&hep->urb_list)
2178 	 */
2179 	if (!qh->is_ready
2180 			|| urb->urb_list.prev != &qh->hep->urb_list
2181 			|| musb_ep_get_qh(qh->hw_ep, is_in) != qh) {
2182 		int	ready = qh->is_ready;
2183 
2184 		qh->is_ready = 0;
2185 		musb_giveback(musb, urb, 0);
2186 		qh->is_ready = ready;
2187 
2188 		/* If nothing else (usually musb_giveback) is using it
2189 		 * and its URB list has emptied, recycle this qh.
2190 		 */
2191 		if (ready && list_empty(&qh->hep->urb_list)) {
2192 			qh->hep->hcpriv = NULL;
2193 			list_del(&qh->ring);
2194 			kfree(qh);
2195 		}
2196 	} else
2197 		ret = musb_cleanup_urb(urb, qh);
2198 done:
2199 	spin_unlock_irqrestore(&musb->lock, flags);
2200 	return ret;
2201 }
2202 
2203 /* disable an endpoint */
2204 static void
2205 musb_h_disable(struct usb_hcd *hcd, struct usb_host_endpoint *hep)
2206 {
2207 	u8			is_in = hep->desc.bEndpointAddress & USB_DIR_IN;
2208 	unsigned long		flags;
2209 	struct musb		*musb = hcd_to_musb(hcd);
2210 	struct musb_qh		*qh;
2211 	struct urb		*urb;
2212 
2213 	spin_lock_irqsave(&musb->lock, flags);
2214 
2215 	qh = hep->hcpriv;
2216 	if (qh == NULL)
2217 		goto exit;
2218 
2219 	/* NOTE: qh is invalid unless !list_empty(&hep->urb_list) */
2220 
2221 	/* Kick the first URB off the hardware, if needed */
2222 	qh->is_ready = 0;
2223 	if (musb_ep_get_qh(qh->hw_ep, is_in) == qh) {
2224 		urb = next_urb(qh);
2225 
2226 		/* make software (then hardware) stop ASAP */
2227 		if (!urb->unlinked)
2228 			urb->status = -ESHUTDOWN;
2229 
2230 		/* cleanup */
2231 		musb_cleanup_urb(urb, qh);
2232 
2233 		/* Then nuke all the others ... and advance the
2234 		 * queue on hw_ep (e.g. bulk ring) when we're done.
2235 		 */
2236 		while (!list_empty(&hep->urb_list)) {
2237 			urb = next_urb(qh);
2238 			urb->status = -ESHUTDOWN;
2239 			musb_advance_schedule(musb, urb, qh->hw_ep, is_in);
2240 		}
2241 	} else {
2242 		/* Just empty the queue; the hardware is busy with
2243 		 * other transfers, and since !qh->is_ready nothing
2244 		 * will activate any of these as it advances.
2245 		 */
2246 		while (!list_empty(&hep->urb_list))
2247 			musb_giveback(musb, next_urb(qh), -ESHUTDOWN);
2248 
2249 		hep->hcpriv = NULL;
2250 		list_del(&qh->ring);
2251 		kfree(qh);
2252 	}
2253 exit:
2254 	spin_unlock_irqrestore(&musb->lock, flags);
2255 }
2256 
2257 static int musb_h_get_frame_number(struct usb_hcd *hcd)
2258 {
2259 	struct musb	*musb = hcd_to_musb(hcd);
2260 
2261 	return musb_readw(musb->mregs, MUSB_FRAME);
2262 }
2263 
2264 static int musb_h_start(struct usb_hcd *hcd)
2265 {
2266 	struct musb	*musb = hcd_to_musb(hcd);
2267 
2268 	/* NOTE: musb_start() is called when the hub driver turns
2269 	 * on port power, or when (OTG) peripheral starts.
2270 	 */
2271 	hcd->state = HC_STATE_RUNNING;
2272 	musb->port1_status = 0;
2273 	return 0;
2274 }
2275 
2276 static void musb_h_stop(struct usb_hcd *hcd)
2277 {
2278 	musb_stop(hcd_to_musb(hcd));
2279 	hcd->state = HC_STATE_HALT;
2280 }
2281 
2282 static int musb_bus_suspend(struct usb_hcd *hcd)
2283 {
2284 	struct musb	*musb = hcd_to_musb(hcd);
2285 	u8		devctl;
2286 
2287 	if (!is_host_active(musb))
2288 		return 0;
2289 
2290 	switch (musb->xceiv->state) {
2291 	case OTG_STATE_A_SUSPEND:
2292 		return 0;
2293 	case OTG_STATE_A_WAIT_VRISE:
2294 		/* ID could be grounded even if there's no device
2295 		 * on the other end of the cable.  NOTE that the
2296 		 * A_WAIT_VRISE timers are messy with MUSB...
2297 		 */
2298 		devctl = musb_readb(musb->mregs, MUSB_DEVCTL);
2299 		if ((devctl & MUSB_DEVCTL_VBUS) == MUSB_DEVCTL_VBUS)
2300 			musb->xceiv->state = OTG_STATE_A_WAIT_BCON;
2301 		break;
2302 	default:
2303 		break;
2304 	}
2305 
2306 	if (musb->is_active) {
2307 		WARNING("trying to suspend as %s while active\n",
2308 				otg_state_string(musb->xceiv->state));
2309 		return -EBUSY;
2310 	} else
2311 		return 0;
2312 }
2313 
2314 static int musb_bus_resume(struct usb_hcd *hcd)
2315 {
2316 	/* resuming child port does the work */
2317 	return 0;
2318 }
2319 
2320 const struct hc_driver musb_hc_driver = {
2321 	.description		= "musb-hcd",
2322 	.product_desc		= "MUSB HDRC host driver",
2323 	.hcd_priv_size		= sizeof(struct musb),
2324 	.flags			= HCD_USB2 | HCD_MEMORY,
2325 
2326 	/* not using irq handler or reset hooks from usbcore, since
2327 	 * those must be shared with peripheral code for OTG configs
2328 	 */
2329 
2330 	.start			= musb_h_start,
2331 	.stop			= musb_h_stop,
2332 
2333 	.get_frame_number	= musb_h_get_frame_number,
2334 
2335 	.urb_enqueue		= musb_urb_enqueue,
2336 	.urb_dequeue		= musb_urb_dequeue,
2337 	.endpoint_disable	= musb_h_disable,
2338 
2339 	.hub_status_data	= musb_hub_status_data,
2340 	.hub_control		= musb_hub_control,
2341 	.bus_suspend		= musb_bus_suspend,
2342 	.bus_resume		= musb_bus_resume,
2343 	/* .start_port_reset	= NULL, */
2344 	/* .hub_irq_enable	= NULL, */
2345 };
2346