xref: /openbmc/linux/drivers/usb/musb/musb_host.c (revision b8bb76713ec50df2f11efee386e16f93d51e1076)
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  * - [23-feb-2009] minimal traffic scheduling to avoid bulk RX packet
68  *   starvation ... nothing yet for TX, interrupt, or bulk.
69  *
70  * - Not tested with HNP, but some SRP paths seem to behave.
71  *
72  * NOTE 24-August-2006:
73  *
74  * - Bulk traffic finally uses both sides of hardware ep1, freeing up an
75  *   extra endpoint for periodic use enabling hub + keybd + mouse.  That
76  *   mostly works, except that with "usbnet" it's easy to trigger cases
77  *   with "ping" where RX loses.  (a) ping to davinci, even "ping -f",
78  *   fine; but (b) ping _from_ davinci, even "ping -c 1", ICMP RX loses
79  *   although ARP RX wins.  (That test was done with a full speed link.)
80  */
81 
82 
83 /*
84  * NOTE on endpoint usage:
85  *
86  * CONTROL transfers all go through ep0.  BULK ones go through dedicated IN
87  * and OUT endpoints ... hardware is dedicated for those "async" queue(s).
88  * (Yes, bulk _could_ use more of the endpoints than that, and would even
89  * benefit from it.)
90  *
91  * INTERUPPT and ISOCHRONOUS transfers are scheduled to the other endpoints.
92  * So far that scheduling is both dumb and optimistic:  the endpoint will be
93  * "claimed" until its software queue is no longer refilled.  No multiplexing
94  * of transfers between endpoints, or anything clever.
95  */
96 
97 
98 static void musb_ep_program(struct musb *musb, u8 epnum,
99 			struct urb *urb, unsigned int nOut,
100 			u8 *buf, u32 len);
101 
102 /*
103  * Clear TX fifo. Needed to avoid BABBLE errors.
104  */
105 static void musb_h_tx_flush_fifo(struct musb_hw_ep *ep)
106 {
107 	void __iomem	*epio = ep->regs;
108 	u16		csr;
109 	u16		lastcsr = 0;
110 	int		retries = 1000;
111 
112 	csr = musb_readw(epio, MUSB_TXCSR);
113 	while (csr & MUSB_TXCSR_FIFONOTEMPTY) {
114 		if (csr != lastcsr)
115 			DBG(3, "Host TX FIFONOTEMPTY csr: %02x\n", csr);
116 		lastcsr = csr;
117 		csr |= MUSB_TXCSR_FLUSHFIFO;
118 		musb_writew(epio, MUSB_TXCSR, csr);
119 		csr = musb_readw(epio, MUSB_TXCSR);
120 		if (WARN(retries-- < 1,
121 				"Could not flush host TX%d fifo: csr: %04x\n",
122 				ep->epnum, csr))
123 			return;
124 		mdelay(1);
125 	}
126 }
127 
128 /*
129  * Start transmit. Caller is responsible for locking shared resources.
130  * musb must be locked.
131  */
132 static inline void musb_h_tx_start(struct musb_hw_ep *ep)
133 {
134 	u16	txcsr;
135 
136 	/* NOTE: no locks here; caller should lock and select EP */
137 	if (ep->epnum) {
138 		txcsr = musb_readw(ep->regs, MUSB_TXCSR);
139 		txcsr |= MUSB_TXCSR_TXPKTRDY | MUSB_TXCSR_H_WZC_BITS;
140 		musb_writew(ep->regs, MUSB_TXCSR, txcsr);
141 	} else {
142 		txcsr = MUSB_CSR0_H_SETUPPKT | MUSB_CSR0_TXPKTRDY;
143 		musb_writew(ep->regs, MUSB_CSR0, txcsr);
144 	}
145 
146 }
147 
148 static inline void cppi_host_txdma_start(struct musb_hw_ep *ep)
149 {
150 	u16	txcsr;
151 
152 	/* NOTE: no locks here; caller should lock and select EP */
153 	txcsr = musb_readw(ep->regs, MUSB_TXCSR);
154 	txcsr |= MUSB_TXCSR_DMAENAB | MUSB_TXCSR_H_WZC_BITS;
155 	musb_writew(ep->regs, MUSB_TXCSR, txcsr);
156 }
157 
158 /*
159  * Start the URB at the front of an endpoint's queue
160  * end must be claimed from the caller.
161  *
162  * Context: controller locked, irqs blocked
163  */
164 static void
165 musb_start_urb(struct musb *musb, int is_in, struct musb_qh *qh)
166 {
167 	u16			frame;
168 	u32			len;
169 	void			*buf;
170 	void __iomem		*mbase =  musb->mregs;
171 	struct urb		*urb = next_urb(qh);
172 	struct musb_hw_ep	*hw_ep = qh->hw_ep;
173 	unsigned		pipe = urb->pipe;
174 	u8			address = usb_pipedevice(pipe);
175 	int			epnum = hw_ep->epnum;
176 
177 	/* initialize software qh state */
178 	qh->offset = 0;
179 	qh->segsize = 0;
180 
181 	/* gather right source of data */
182 	switch (qh->type) {
183 	case USB_ENDPOINT_XFER_CONTROL:
184 		/* control transfers always start with SETUP */
185 		is_in = 0;
186 		hw_ep->out_qh = qh;
187 		musb->ep0_stage = MUSB_EP0_START;
188 		buf = urb->setup_packet;
189 		len = 8;
190 		break;
191 	case USB_ENDPOINT_XFER_ISOC:
192 		qh->iso_idx = 0;
193 		qh->frame = 0;
194 		buf = urb->transfer_buffer + urb->iso_frame_desc[0].offset;
195 		len = urb->iso_frame_desc[0].length;
196 		break;
197 	default:		/* bulk, interrupt */
198 		/* actual_length may be nonzero on retry paths */
199 		buf = urb->transfer_buffer + urb->actual_length;
200 		len = urb->transfer_buffer_length - urb->actual_length;
201 	}
202 
203 	DBG(4, "qh %p urb %p dev%d ep%d%s%s, hw_ep %d, %p/%d\n",
204 			qh, urb, address, qh->epnum,
205 			is_in ? "in" : "out",
206 			({char *s; switch (qh->type) {
207 			case USB_ENDPOINT_XFER_CONTROL:	s = ""; break;
208 			case USB_ENDPOINT_XFER_BULK:	s = "-bulk"; break;
209 			case USB_ENDPOINT_XFER_ISOC:	s = "-iso"; break;
210 			default:			s = "-intr"; break;
211 			}; s; }),
212 			epnum, buf, len);
213 
214 	/* Configure endpoint */
215 	if (is_in || hw_ep->is_shared_fifo)
216 		hw_ep->in_qh = qh;
217 	else
218 		hw_ep->out_qh = qh;
219 	musb_ep_program(musb, epnum, urb, !is_in, buf, len);
220 
221 	/* transmit may have more work: start it when it is time */
222 	if (is_in)
223 		return;
224 
225 	/* determine if the time is right for a periodic transfer */
226 	switch (qh->type) {
227 	case USB_ENDPOINT_XFER_ISOC:
228 	case USB_ENDPOINT_XFER_INT:
229 		DBG(3, "check whether there's still time for periodic Tx\n");
230 		qh->iso_idx = 0;
231 		frame = musb_readw(mbase, MUSB_FRAME);
232 		/* FIXME this doesn't implement that scheduling policy ...
233 		 * or handle framecounter wrapping
234 		 */
235 		if ((urb->transfer_flags & URB_ISO_ASAP)
236 				|| (frame >= urb->start_frame)) {
237 			/* REVISIT the SOF irq handler shouldn't duplicate
238 			 * this code; and we don't init urb->start_frame...
239 			 */
240 			qh->frame = 0;
241 			goto start;
242 		} else {
243 			qh->frame = urb->start_frame;
244 			/* enable SOF interrupt so we can count down */
245 			DBG(1, "SOF for %d\n", epnum);
246 #if 1 /* ifndef	CONFIG_ARCH_DAVINCI */
247 			musb_writeb(mbase, MUSB_INTRUSBE, 0xff);
248 #endif
249 		}
250 		break;
251 	default:
252 start:
253 		DBG(4, "Start TX%d %s\n", epnum,
254 			hw_ep->tx_channel ? "dma" : "pio");
255 
256 		if (!hw_ep->tx_channel)
257 			musb_h_tx_start(hw_ep);
258 		else if (is_cppi_enabled() || tusb_dma_omap())
259 			cppi_host_txdma_start(hw_ep);
260 	}
261 }
262 
263 /* caller owns controller lock, irqs are blocked */
264 static void
265 __musb_giveback(struct musb *musb, struct urb *urb, int status)
266 __releases(musb->lock)
267 __acquires(musb->lock)
268 {
269 	DBG(({ int level; switch (status) {
270 				case 0:
271 					level = 4;
272 					break;
273 				/* common/boring faults */
274 				case -EREMOTEIO:
275 				case -ESHUTDOWN:
276 				case -ECONNRESET:
277 				case -EPIPE:
278 					level = 3;
279 					break;
280 				default:
281 					level = 2;
282 					break;
283 				}; level; }),
284 			"complete %p %pF (%d), dev%d ep%d%s, %d/%d\n",
285 			urb, urb->complete, status,
286 			usb_pipedevice(urb->pipe),
287 			usb_pipeendpoint(urb->pipe),
288 			usb_pipein(urb->pipe) ? "in" : "out",
289 			urb->actual_length, urb->transfer_buffer_length
290 			);
291 
292 	usb_hcd_unlink_urb_from_ep(musb_to_hcd(musb), urb);
293 	spin_unlock(&musb->lock);
294 	usb_hcd_giveback_urb(musb_to_hcd(musb), urb, status);
295 	spin_lock(&musb->lock);
296 }
297 
298 /* for bulk/interrupt endpoints only */
299 static inline void
300 musb_save_toggle(struct musb_hw_ep *ep, int is_in, struct urb *urb)
301 {
302 	struct usb_device	*udev = urb->dev;
303 	u16			csr;
304 	void __iomem		*epio = ep->regs;
305 	struct musb_qh		*qh;
306 
307 	/* FIXME:  the current Mentor DMA code seems to have
308 	 * problems getting toggle correct.
309 	 */
310 
311 	if (is_in || ep->is_shared_fifo)
312 		qh = ep->in_qh;
313 	else
314 		qh = ep->out_qh;
315 
316 	if (!is_in) {
317 		csr = musb_readw(epio, MUSB_TXCSR);
318 		usb_settoggle(udev, qh->epnum, 1,
319 			(csr & MUSB_TXCSR_H_DATATOGGLE)
320 				? 1 : 0);
321 	} else {
322 		csr = musb_readw(epio, MUSB_RXCSR);
323 		usb_settoggle(udev, qh->epnum, 0,
324 			(csr & MUSB_RXCSR_H_DATATOGGLE)
325 				? 1 : 0);
326 	}
327 }
328 
329 /* caller owns controller lock, irqs are blocked */
330 static struct musb_qh *
331 musb_giveback(struct musb_qh *qh, struct urb *urb, int status)
332 {
333 	struct musb_hw_ep	*ep = qh->hw_ep;
334 	struct musb		*musb = ep->musb;
335 	int			is_in = usb_pipein(urb->pipe);
336 	int			ready = qh->is_ready;
337 
338 	/* save toggle eagerly, for paranoia */
339 	switch (qh->type) {
340 	case USB_ENDPOINT_XFER_BULK:
341 	case USB_ENDPOINT_XFER_INT:
342 		musb_save_toggle(ep, is_in, urb);
343 		break;
344 	case USB_ENDPOINT_XFER_ISOC:
345 		if (status == 0 && urb->error_count)
346 			status = -EXDEV;
347 		break;
348 	}
349 
350 	qh->is_ready = 0;
351 	__musb_giveback(musb, urb, status);
352 	qh->is_ready = ready;
353 
354 	/* reclaim resources (and bandwidth) ASAP; deschedule it, and
355 	 * invalidate qh as soon as list_empty(&hep->urb_list)
356 	 */
357 	if (list_empty(&qh->hep->urb_list)) {
358 		struct list_head	*head;
359 
360 		if (is_in)
361 			ep->rx_reinit = 1;
362 		else
363 			ep->tx_reinit = 1;
364 
365 		/* clobber old pointers to this qh */
366 		if (is_in || ep->is_shared_fifo)
367 			ep->in_qh = NULL;
368 		else
369 			ep->out_qh = NULL;
370 		qh->hep->hcpriv = NULL;
371 
372 		switch (qh->type) {
373 
374 		case USB_ENDPOINT_XFER_CONTROL:
375 		case USB_ENDPOINT_XFER_BULK:
376 			/* fifo policy for these lists, except that NAKing
377 			 * should rotate a qh to the end (for fairness).
378 			 */
379 			if (qh->mux == 1) {
380 				head = qh->ring.prev;
381 				list_del(&qh->ring);
382 				kfree(qh);
383 				qh = first_qh(head);
384 				break;
385 			}
386 
387 		case USB_ENDPOINT_XFER_ISOC:
388 		case USB_ENDPOINT_XFER_INT:
389 			/* this is where periodic bandwidth should be
390 			 * de-allocated if it's tracked and allocated;
391 			 * and where we'd update the schedule tree...
392 			 */
393 			kfree(qh);
394 			qh = NULL;
395 			break;
396 		}
397 	}
398 	return qh;
399 }
400 
401 /*
402  * Advance this hardware endpoint's queue, completing the specified urb and
403  * advancing to either the next urb queued to that qh, or else invalidating
404  * that qh and advancing to the next qh scheduled after the current one.
405  *
406  * Context: caller owns controller lock, irqs are blocked
407  */
408 static void
409 musb_advance_schedule(struct musb *musb, struct urb *urb,
410 		struct musb_hw_ep *hw_ep, int is_in)
411 {
412 	struct musb_qh	*qh;
413 
414 	if (is_in || hw_ep->is_shared_fifo)
415 		qh = hw_ep->in_qh;
416 	else
417 		qh = hw_ep->out_qh;
418 
419 	if (urb->status == -EINPROGRESS)
420 		qh = musb_giveback(qh, urb, 0);
421 	else
422 		qh = musb_giveback(qh, urb, urb->status);
423 
424 	if (qh != NULL && qh->is_ready) {
425 		DBG(4, "... next ep%d %cX urb %p\n",
426 				hw_ep->epnum, is_in ? 'R' : 'T',
427 				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 	DBG(3, "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 			DBG(2, "** 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 			DBG(2, "** 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 			musb_writew(ep->regs, MUSB_TXCSR,
571 					MUSB_TXCSR_FRCDATATOG);
572 		}
573 		/* clear mode (and everything else) to enable Rx */
574 		musb_writew(ep->regs, MUSB_TXCSR, 0);
575 
576 	/* scrub all previous state, clearing toggle */
577 	} else {
578 		csr = musb_readw(ep->regs, MUSB_RXCSR);
579 		if (csr & MUSB_RXCSR_RXPKTRDY)
580 			WARNING("rx%d, packet/%d ready?\n", ep->epnum,
581 				musb_readw(ep->regs, MUSB_RXCOUNT));
582 
583 		musb_h_flush_rxfifo(ep, MUSB_RXCSR_CLRDATATOG);
584 	}
585 
586 	/* target addr and (for multipoint) hub addr/port */
587 	if (musb->is_multipoint) {
588 		musb_write_rxfunaddr(ep->target_regs, qh->addr_reg);
589 		musb_write_rxhubaddr(ep->target_regs, qh->h_addr_reg);
590 		musb_write_rxhubport(ep->target_regs, qh->h_port_reg);
591 
592 	} else
593 		musb_writeb(musb->mregs, MUSB_FADDR, qh->addr_reg);
594 
595 	/* protocol/endpoint, interval/NAKlimit, i/o size */
596 	musb_writeb(ep->regs, MUSB_RXTYPE, qh->type_reg);
597 	musb_writeb(ep->regs, MUSB_RXINTERVAL, qh->intv_reg);
598 	/* NOTE: bulk combining rewrites high bits of maxpacket */
599 	musb_writew(ep->regs, MUSB_RXMAXP, qh->maxpacket);
600 
601 	ep->rx_reinit = 0;
602 }
603 
604 
605 /*
606  * Program an HDRC endpoint as per the given URB
607  * Context: irqs blocked, controller lock held
608  */
609 static void musb_ep_program(struct musb *musb, u8 epnum,
610 			struct urb *urb, unsigned int is_out,
611 			u8 *buf, u32 len)
612 {
613 	struct dma_controller	*dma_controller;
614 	struct dma_channel	*dma_channel;
615 	u8			dma_ok;
616 	void __iomem		*mbase = musb->mregs;
617 	struct musb_hw_ep	*hw_ep = musb->endpoints + epnum;
618 	void __iomem		*epio = hw_ep->regs;
619 	struct musb_qh		*qh;
620 	u16			packet_sz;
621 
622 	if (!is_out || hw_ep->is_shared_fifo)
623 		qh = hw_ep->in_qh;
624 	else
625 		qh = hw_ep->out_qh;
626 
627 	packet_sz = qh->maxpacket;
628 
629 	DBG(3, "%s hw%d urb %p spd%d dev%d ep%d%s "
630 				"h_addr%02x h_port%02x bytes %d\n",
631 			is_out ? "-->" : "<--",
632 			epnum, urb, urb->dev->speed,
633 			qh->addr_reg, qh->epnum, is_out ? "out" : "in",
634 			qh->h_addr_reg, qh->h_port_reg,
635 			len);
636 
637 	musb_ep_select(mbase, epnum);
638 
639 	/* candidate for DMA? */
640 	dma_controller = musb->dma_controller;
641 	if (is_dma_capable() && epnum && dma_controller) {
642 		dma_channel = is_out ? hw_ep->tx_channel : hw_ep->rx_channel;
643 		if (!dma_channel) {
644 			dma_channel = dma_controller->channel_alloc(
645 					dma_controller, hw_ep, is_out);
646 			if (is_out)
647 				hw_ep->tx_channel = dma_channel;
648 			else
649 				hw_ep->rx_channel = dma_channel;
650 		}
651 	} else
652 		dma_channel = NULL;
653 
654 	/* make sure we clear DMAEnab, autoSet bits from previous run */
655 
656 	/* OUT/transmit/EP0 or IN/receive? */
657 	if (is_out) {
658 		u16	csr;
659 		u16	int_txe;
660 		u16	load_count;
661 
662 		csr = musb_readw(epio, MUSB_TXCSR);
663 
664 		/* disable interrupt in case we flush */
665 		int_txe = musb_readw(mbase, MUSB_INTRTXE);
666 		musb_writew(mbase, MUSB_INTRTXE, int_txe & ~(1 << epnum));
667 
668 		/* general endpoint setup */
669 		if (epnum) {
670 			/* ASSERT:  TXCSR_DMAENAB was already cleared */
671 
672 			/* flush all old state, set default */
673 			musb_h_tx_flush_fifo(hw_ep);
674 			csr &= ~(MUSB_TXCSR_H_NAKTIMEOUT
675 					| MUSB_TXCSR_DMAMODE
676 					| MUSB_TXCSR_FRCDATATOG
677 					| MUSB_TXCSR_H_RXSTALL
678 					| MUSB_TXCSR_H_ERROR
679 					| MUSB_TXCSR_TXPKTRDY
680 					);
681 			csr |= MUSB_TXCSR_MODE;
682 
683 			if (usb_gettoggle(urb->dev,
684 					qh->epnum, 1))
685 				csr |= MUSB_TXCSR_H_WR_DATATOGGLE
686 					| MUSB_TXCSR_H_DATATOGGLE;
687 			else
688 				csr |= MUSB_TXCSR_CLRDATATOG;
689 
690 			/* twice in case of double packet buffering */
691 			musb_writew(epio, MUSB_TXCSR, csr);
692 			/* REVISIT may need to clear FLUSHFIFO ... */
693 			musb_writew(epio, MUSB_TXCSR, csr);
694 			csr = musb_readw(epio, MUSB_TXCSR);
695 		} else {
696 			/* endpoint 0: just flush */
697 			musb_writew(epio, MUSB_CSR0,
698 				csr | MUSB_CSR0_FLUSHFIFO);
699 			musb_writew(epio, MUSB_CSR0,
700 				csr | MUSB_CSR0_FLUSHFIFO);
701 		}
702 
703 		/* target addr and (for multipoint) hub addr/port */
704 		if (musb->is_multipoint) {
705 			musb_write_txfunaddr(mbase, epnum, qh->addr_reg);
706 			musb_write_txhubaddr(mbase, epnum, qh->h_addr_reg);
707 			musb_write_txhubport(mbase, epnum, qh->h_port_reg);
708 /* FIXME if !epnum, do the same for RX ... */
709 		} else
710 			musb_writeb(mbase, MUSB_FADDR, qh->addr_reg);
711 
712 		/* protocol/endpoint/interval/NAKlimit */
713 		if (epnum) {
714 			musb_writeb(epio, MUSB_TXTYPE, qh->type_reg);
715 			if (can_bulk_split(musb, qh->type))
716 				musb_writew(epio, MUSB_TXMAXP,
717 					packet_sz
718 					| ((hw_ep->max_packet_sz_tx /
719 						packet_sz) - 1) << 11);
720 			else
721 				musb_writew(epio, MUSB_TXMAXP,
722 					packet_sz);
723 			musb_writeb(epio, MUSB_TXINTERVAL, qh->intv_reg);
724 		} else {
725 			musb_writeb(epio, MUSB_NAKLIMIT0, qh->intv_reg);
726 			if (musb->is_multipoint)
727 				musb_writeb(epio, MUSB_TYPE0,
728 						qh->type_reg);
729 		}
730 
731 		if (can_bulk_split(musb, qh->type))
732 			load_count = min((u32) hw_ep->max_packet_sz_tx,
733 						len);
734 		else
735 			load_count = min((u32) packet_sz, len);
736 
737 #ifdef CONFIG_USB_INVENTRA_DMA
738 		if (dma_channel) {
739 
740 			/* clear previous state */
741 			csr = musb_readw(epio, MUSB_TXCSR);
742 			csr &= ~(MUSB_TXCSR_AUTOSET
743 				| MUSB_TXCSR_DMAMODE
744 				| MUSB_TXCSR_DMAENAB);
745 			csr |= MUSB_TXCSR_MODE;
746 			musb_writew(epio, MUSB_TXCSR,
747 				csr | MUSB_TXCSR_MODE);
748 
749 			qh->segsize = min(len, dma_channel->max_len);
750 
751 			if (qh->segsize <= packet_sz)
752 				dma_channel->desired_mode = 0;
753 			else
754 				dma_channel->desired_mode = 1;
755 
756 
757 			if (dma_channel->desired_mode == 0) {
758 				csr &= ~(MUSB_TXCSR_AUTOSET
759 					| MUSB_TXCSR_DMAMODE);
760 				csr |= (MUSB_TXCSR_DMAENAB);
761 					/* against programming guide */
762 			} else
763 				csr |= (MUSB_TXCSR_AUTOSET
764 					| MUSB_TXCSR_DMAENAB
765 					| MUSB_TXCSR_DMAMODE);
766 
767 			musb_writew(epio, MUSB_TXCSR, csr);
768 
769 			dma_ok = dma_controller->channel_program(
770 					dma_channel, packet_sz,
771 					dma_channel->desired_mode,
772 					urb->transfer_dma,
773 					qh->segsize);
774 			if (dma_ok) {
775 				load_count = 0;
776 			} else {
777 				dma_controller->channel_release(dma_channel);
778 				if (is_out)
779 					hw_ep->tx_channel = NULL;
780 				else
781 					hw_ep->rx_channel = NULL;
782 				dma_channel = NULL;
783 			}
784 		}
785 #endif
786 
787 		/* candidate for DMA */
788 		if ((is_cppi_enabled() || tusb_dma_omap()) && dma_channel) {
789 
790 			/* program endpoint CSRs first, then setup DMA.
791 			 * assume CPPI setup succeeds.
792 			 * defer enabling dma.
793 			 */
794 			csr = musb_readw(epio, MUSB_TXCSR);
795 			csr &= ~(MUSB_TXCSR_AUTOSET
796 					| MUSB_TXCSR_DMAMODE
797 					| MUSB_TXCSR_DMAENAB);
798 			csr |= MUSB_TXCSR_MODE;
799 			musb_writew(epio, MUSB_TXCSR,
800 				csr | MUSB_TXCSR_MODE);
801 
802 			dma_channel->actual_len = 0L;
803 			qh->segsize = len;
804 
805 			/* TX uses "rndis" mode automatically, but needs help
806 			 * to identify the zero-length-final-packet case.
807 			 */
808 			dma_ok = dma_controller->channel_program(
809 					dma_channel, packet_sz,
810 					(urb->transfer_flags
811 							& URB_ZERO_PACKET)
812 						== URB_ZERO_PACKET,
813 					urb->transfer_dma,
814 					qh->segsize);
815 			if (dma_ok) {
816 				load_count = 0;
817 			} else {
818 				dma_controller->channel_release(dma_channel);
819 				hw_ep->tx_channel = NULL;
820 				dma_channel = NULL;
821 
822 				/* REVISIT there's an error path here that
823 				 * needs handling:  can't do dma, but
824 				 * there's no pio buffer address...
825 				 */
826 			}
827 		}
828 
829 		if (load_count) {
830 			/* ASSERT:  TXCSR_DMAENAB was already cleared */
831 
832 			/* PIO to load FIFO */
833 			qh->segsize = load_count;
834 			musb_write_fifo(hw_ep, load_count, buf);
835 			csr = musb_readw(epio, MUSB_TXCSR);
836 			csr &= ~(MUSB_TXCSR_DMAENAB
837 				| MUSB_TXCSR_DMAMODE
838 				| MUSB_TXCSR_AUTOSET);
839 			/* write CSR */
840 			csr |= MUSB_TXCSR_MODE;
841 
842 			if (epnum)
843 				musb_writew(epio, MUSB_TXCSR, csr);
844 		}
845 
846 		/* re-enable interrupt */
847 		musb_writew(mbase, MUSB_INTRTXE, int_txe);
848 
849 	/* IN/receive */
850 	} else {
851 		u16	csr;
852 
853 		if (hw_ep->rx_reinit) {
854 			musb_rx_reinit(musb, qh, hw_ep);
855 
856 			/* init new state: toggle and NYET, maybe DMA later */
857 			if (usb_gettoggle(urb->dev, qh->epnum, 0))
858 				csr = MUSB_RXCSR_H_WR_DATATOGGLE
859 					| MUSB_RXCSR_H_DATATOGGLE;
860 			else
861 				csr = 0;
862 			if (qh->type == USB_ENDPOINT_XFER_INT)
863 				csr |= MUSB_RXCSR_DISNYET;
864 
865 		} else {
866 			csr = musb_readw(hw_ep->regs, MUSB_RXCSR);
867 
868 			if (csr & (MUSB_RXCSR_RXPKTRDY
869 					| MUSB_RXCSR_DMAENAB
870 					| MUSB_RXCSR_H_REQPKT))
871 				ERR("broken !rx_reinit, ep%d csr %04x\n",
872 						hw_ep->epnum, csr);
873 
874 			/* scrub any stale state, leaving toggle alone */
875 			csr &= MUSB_RXCSR_DISNYET;
876 		}
877 
878 		/* kick things off */
879 
880 		if ((is_cppi_enabled() || tusb_dma_omap()) && dma_channel) {
881 			/* candidate for DMA */
882 			if (dma_channel) {
883 				dma_channel->actual_len = 0L;
884 				qh->segsize = len;
885 
886 				/* AUTOREQ is in a DMA register */
887 				musb_writew(hw_ep->regs, MUSB_RXCSR, csr);
888 				csr = musb_readw(hw_ep->regs,
889 						MUSB_RXCSR);
890 
891 				/* unless caller treats short rx transfers as
892 				 * errors, we dare not queue multiple transfers.
893 				 */
894 				dma_ok = dma_controller->channel_program(
895 						dma_channel, packet_sz,
896 						!(urb->transfer_flags
897 							& URB_SHORT_NOT_OK),
898 						urb->transfer_dma,
899 						qh->segsize);
900 				if (!dma_ok) {
901 					dma_controller->channel_release(
902 							dma_channel);
903 					hw_ep->rx_channel = NULL;
904 					dma_channel = NULL;
905 				} else
906 					csr |= MUSB_RXCSR_DMAENAB;
907 			}
908 		}
909 
910 		csr |= MUSB_RXCSR_H_REQPKT;
911 		DBG(7, "RXCSR%d := %04x\n", epnum, csr);
912 		musb_writew(hw_ep->regs, MUSB_RXCSR, csr);
913 		csr = musb_readw(hw_ep->regs, MUSB_RXCSR);
914 	}
915 }
916 
917 
918 /*
919  * Service the default endpoint (ep0) as host.
920  * Return true until it's time to start the status stage.
921  */
922 static bool musb_h_ep0_continue(struct musb *musb, u16 len, struct urb *urb)
923 {
924 	bool			 more = false;
925 	u8			*fifo_dest = NULL;
926 	u16			fifo_count = 0;
927 	struct musb_hw_ep	*hw_ep = musb->control_ep;
928 	struct musb_qh		*qh = hw_ep->in_qh;
929 	struct usb_ctrlrequest	*request;
930 
931 	switch (musb->ep0_stage) {
932 	case MUSB_EP0_IN:
933 		fifo_dest = urb->transfer_buffer + urb->actual_length;
934 		fifo_count = min_t(size_t, len, urb->transfer_buffer_length -
935 				   urb->actual_length);
936 		if (fifo_count < len)
937 			urb->status = -EOVERFLOW;
938 
939 		musb_read_fifo(hw_ep, fifo_count, fifo_dest);
940 
941 		urb->actual_length += fifo_count;
942 		if (len < qh->maxpacket) {
943 			/* always terminate on short read; it's
944 			 * rarely reported as an error.
945 			 */
946 		} else if (urb->actual_length <
947 				urb->transfer_buffer_length)
948 			more = true;
949 		break;
950 	case MUSB_EP0_START:
951 		request = (struct usb_ctrlrequest *) urb->setup_packet;
952 
953 		if (!request->wLength) {
954 			DBG(4, "start no-DATA\n");
955 			break;
956 		} else if (request->bRequestType & USB_DIR_IN) {
957 			DBG(4, "start IN-DATA\n");
958 			musb->ep0_stage = MUSB_EP0_IN;
959 			more = true;
960 			break;
961 		} else {
962 			DBG(4, "start OUT-DATA\n");
963 			musb->ep0_stage = MUSB_EP0_OUT;
964 			more = true;
965 		}
966 		/* FALLTHROUGH */
967 	case MUSB_EP0_OUT:
968 		fifo_count = min_t(size_t, qh->maxpacket,
969 				   urb->transfer_buffer_length -
970 				   urb->actual_length);
971 		if (fifo_count) {
972 			fifo_dest = (u8 *) (urb->transfer_buffer
973 					+ urb->actual_length);
974 			DBG(3, "Sending %d byte%s to ep0 fifo %p\n",
975 					fifo_count,
976 					(fifo_count == 1) ? "" : "s",
977 					fifo_dest);
978 			musb_write_fifo(hw_ep, fifo_count, fifo_dest);
979 
980 			urb->actual_length += fifo_count;
981 			more = true;
982 		}
983 		break;
984 	default:
985 		ERR("bogus ep0 stage %d\n", musb->ep0_stage);
986 		break;
987 	}
988 
989 	return more;
990 }
991 
992 /*
993  * Handle default endpoint interrupt as host. Only called in IRQ time
994  * from musb_interrupt().
995  *
996  * called with controller irqlocked
997  */
998 irqreturn_t musb_h_ep0_irq(struct musb *musb)
999 {
1000 	struct urb		*urb;
1001 	u16			csr, len;
1002 	int			status = 0;
1003 	void __iomem		*mbase = musb->mregs;
1004 	struct musb_hw_ep	*hw_ep = musb->control_ep;
1005 	void __iomem		*epio = hw_ep->regs;
1006 	struct musb_qh		*qh = hw_ep->in_qh;
1007 	bool			complete = false;
1008 	irqreturn_t		retval = IRQ_NONE;
1009 
1010 	/* ep0 only has one queue, "in" */
1011 	urb = next_urb(qh);
1012 
1013 	musb_ep_select(mbase, 0);
1014 	csr = musb_readw(epio, MUSB_CSR0);
1015 	len = (csr & MUSB_CSR0_RXPKTRDY)
1016 			? musb_readb(epio, MUSB_COUNT0)
1017 			: 0;
1018 
1019 	DBG(4, "<== csr0 %04x, qh %p, count %d, urb %p, stage %d\n",
1020 		csr, qh, len, urb, musb->ep0_stage);
1021 
1022 	/* if we just did status stage, we are done */
1023 	if (MUSB_EP0_STATUS == musb->ep0_stage) {
1024 		retval = IRQ_HANDLED;
1025 		complete = true;
1026 	}
1027 
1028 	/* prepare status */
1029 	if (csr & MUSB_CSR0_H_RXSTALL) {
1030 		DBG(6, "STALLING ENDPOINT\n");
1031 		status = -EPIPE;
1032 
1033 	} else if (csr & MUSB_CSR0_H_ERROR) {
1034 		DBG(2, "no response, csr0 %04x\n", csr);
1035 		status = -EPROTO;
1036 
1037 	} else if (csr & MUSB_CSR0_H_NAKTIMEOUT) {
1038 		DBG(2, "control NAK timeout\n");
1039 
1040 		/* NOTE:  this code path would be a good place to PAUSE a
1041 		 * control transfer, if another one is queued, so that
1042 		 * ep0 is more likely to stay busy.  That's already done
1043 		 * for bulk RX transfers.
1044 		 *
1045 		 * if (qh->ring.next != &musb->control), then
1046 		 * we have a candidate... NAKing is *NOT* an error
1047 		 */
1048 		musb_writew(epio, MUSB_CSR0, 0);
1049 		retval = IRQ_HANDLED;
1050 	}
1051 
1052 	if (status) {
1053 		DBG(6, "aborting\n");
1054 		retval = IRQ_HANDLED;
1055 		if (urb)
1056 			urb->status = status;
1057 		complete = true;
1058 
1059 		/* use the proper sequence to abort the transfer */
1060 		if (csr & MUSB_CSR0_H_REQPKT) {
1061 			csr &= ~MUSB_CSR0_H_REQPKT;
1062 			musb_writew(epio, MUSB_CSR0, csr);
1063 			csr &= ~MUSB_CSR0_H_NAKTIMEOUT;
1064 			musb_writew(epio, MUSB_CSR0, csr);
1065 		} else {
1066 			csr |= MUSB_CSR0_FLUSHFIFO;
1067 			musb_writew(epio, MUSB_CSR0, csr);
1068 			musb_writew(epio, MUSB_CSR0, csr);
1069 			csr &= ~MUSB_CSR0_H_NAKTIMEOUT;
1070 			musb_writew(epio, MUSB_CSR0, csr);
1071 		}
1072 
1073 		musb_writeb(epio, MUSB_NAKLIMIT0, 0);
1074 
1075 		/* clear it */
1076 		musb_writew(epio, MUSB_CSR0, 0);
1077 	}
1078 
1079 	if (unlikely(!urb)) {
1080 		/* stop endpoint since we have no place for its data, this
1081 		 * SHOULD NEVER HAPPEN! */
1082 		ERR("no URB for end 0\n");
1083 
1084 		musb_writew(epio, MUSB_CSR0, MUSB_CSR0_FLUSHFIFO);
1085 		musb_writew(epio, MUSB_CSR0, MUSB_CSR0_FLUSHFIFO);
1086 		musb_writew(epio, MUSB_CSR0, 0);
1087 
1088 		goto done;
1089 	}
1090 
1091 	if (!complete) {
1092 		/* call common logic and prepare response */
1093 		if (musb_h_ep0_continue(musb, len, urb)) {
1094 			/* more packets required */
1095 			csr = (MUSB_EP0_IN == musb->ep0_stage)
1096 				?  MUSB_CSR0_H_REQPKT : MUSB_CSR0_TXPKTRDY;
1097 		} else {
1098 			/* data transfer complete; perform status phase */
1099 			if (usb_pipeout(urb->pipe)
1100 					|| !urb->transfer_buffer_length)
1101 				csr = MUSB_CSR0_H_STATUSPKT
1102 					| MUSB_CSR0_H_REQPKT;
1103 			else
1104 				csr = MUSB_CSR0_H_STATUSPKT
1105 					| MUSB_CSR0_TXPKTRDY;
1106 
1107 			/* flag status stage */
1108 			musb->ep0_stage = MUSB_EP0_STATUS;
1109 
1110 			DBG(5, "ep0 STATUS, csr %04x\n", csr);
1111 
1112 		}
1113 		musb_writew(epio, MUSB_CSR0, csr);
1114 		retval = IRQ_HANDLED;
1115 	} else
1116 		musb->ep0_stage = MUSB_EP0_IDLE;
1117 
1118 	/* call completion handler if done */
1119 	if (complete)
1120 		musb_advance_schedule(musb, urb, hw_ep, 1);
1121 done:
1122 	return retval;
1123 }
1124 
1125 
1126 #ifdef CONFIG_USB_INVENTRA_DMA
1127 
1128 /* Host side TX (OUT) using Mentor DMA works as follows:
1129 	submit_urb ->
1130 		- if queue was empty, Program Endpoint
1131 		- ... which starts DMA to fifo in mode 1 or 0
1132 
1133 	DMA Isr (transfer complete) -> TxAvail()
1134 		- Stop DMA (~DmaEnab)	(<--- Alert ... currently happens
1135 					only in musb_cleanup_urb)
1136 		- TxPktRdy has to be set in mode 0 or for
1137 			short packets in mode 1.
1138 */
1139 
1140 #endif
1141 
1142 /* Service a Tx-Available or dma completion irq for the endpoint */
1143 void musb_host_tx(struct musb *musb, u8 epnum)
1144 {
1145 	int			pipe;
1146 	bool			done = false;
1147 	u16			tx_csr;
1148 	size_t			wLength = 0;
1149 	u8			*buf = NULL;
1150 	struct urb		*urb;
1151 	struct musb_hw_ep	*hw_ep = musb->endpoints + epnum;
1152 	void __iomem		*epio = hw_ep->regs;
1153 	struct musb_qh		*qh = hw_ep->is_shared_fifo ? hw_ep->in_qh
1154 							    : hw_ep->out_qh;
1155 	u32			status = 0;
1156 	void __iomem		*mbase = musb->mregs;
1157 	struct dma_channel	*dma;
1158 
1159 	urb = next_urb(qh);
1160 
1161 	musb_ep_select(mbase, epnum);
1162 	tx_csr = musb_readw(epio, MUSB_TXCSR);
1163 
1164 	/* with CPPI, DMA sometimes triggers "extra" irqs */
1165 	if (!urb) {
1166 		DBG(4, "extra TX%d ready, csr %04x\n", epnum, tx_csr);
1167 		goto finish;
1168 	}
1169 
1170 	pipe = urb->pipe;
1171 	dma = is_dma_capable() ? hw_ep->tx_channel : NULL;
1172 	DBG(4, "OUT/TX%d end, csr %04x%s\n", epnum, tx_csr,
1173 			dma ? ", dma" : "");
1174 
1175 	/* check for errors */
1176 	if (tx_csr & MUSB_TXCSR_H_RXSTALL) {
1177 		/* dma was disabled, fifo flushed */
1178 		DBG(3, "TX end %d stall\n", epnum);
1179 
1180 		/* stall; record URB status */
1181 		status = -EPIPE;
1182 
1183 	} else if (tx_csr & MUSB_TXCSR_H_ERROR) {
1184 		/* (NON-ISO) dma was disabled, fifo flushed */
1185 		DBG(3, "TX 3strikes on ep=%d\n", epnum);
1186 
1187 		status = -ETIMEDOUT;
1188 
1189 	} else if (tx_csr & MUSB_TXCSR_H_NAKTIMEOUT) {
1190 		DBG(6, "TX end=%d device not responding\n", epnum);
1191 
1192 		/* NOTE:  this code path would be a good place to PAUSE a
1193 		 * transfer, if there's some other (nonperiodic) tx urb
1194 		 * that could use this fifo.  (dma complicates it...)
1195 		 * That's already done for bulk RX transfers.
1196 		 *
1197 		 * if (bulk && qh->ring.next != &musb->out_bulk), then
1198 		 * we have a candidate... NAKing is *NOT* an error
1199 		 */
1200 		musb_ep_select(mbase, epnum);
1201 		musb_writew(epio, MUSB_TXCSR,
1202 				MUSB_TXCSR_H_WZC_BITS
1203 				| MUSB_TXCSR_TXPKTRDY);
1204 		goto finish;
1205 	}
1206 
1207 	if (status) {
1208 		if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1209 			dma->status = MUSB_DMA_STATUS_CORE_ABORT;
1210 			(void) musb->dma_controller->channel_abort(dma);
1211 		}
1212 
1213 		/* do the proper sequence to abort the transfer in the
1214 		 * usb core; the dma engine should already be stopped.
1215 		 */
1216 		musb_h_tx_flush_fifo(hw_ep);
1217 		tx_csr &= ~(MUSB_TXCSR_AUTOSET
1218 				| MUSB_TXCSR_DMAENAB
1219 				| MUSB_TXCSR_H_ERROR
1220 				| MUSB_TXCSR_H_RXSTALL
1221 				| MUSB_TXCSR_H_NAKTIMEOUT
1222 				);
1223 
1224 		musb_ep_select(mbase, epnum);
1225 		musb_writew(epio, MUSB_TXCSR, tx_csr);
1226 		/* REVISIT may need to clear FLUSHFIFO ... */
1227 		musb_writew(epio, MUSB_TXCSR, tx_csr);
1228 		musb_writeb(epio, MUSB_TXINTERVAL, 0);
1229 
1230 		done = true;
1231 	}
1232 
1233 	/* second cppi case */
1234 	if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1235 		DBG(4, "extra TX%d ready, csr %04x\n", epnum, tx_csr);
1236 		goto finish;
1237 
1238 	}
1239 
1240 	/* REVISIT this looks wrong... */
1241 	if (!status || dma || usb_pipeisoc(pipe)) {
1242 		if (dma)
1243 			wLength = dma->actual_len;
1244 		else
1245 			wLength = qh->segsize;
1246 		qh->offset += wLength;
1247 
1248 		if (usb_pipeisoc(pipe)) {
1249 			struct usb_iso_packet_descriptor	*d;
1250 
1251 			d = urb->iso_frame_desc + qh->iso_idx;
1252 			d->actual_length = qh->segsize;
1253 			if (++qh->iso_idx >= urb->number_of_packets) {
1254 				done = true;
1255 			} else {
1256 				d++;
1257 				buf = urb->transfer_buffer + d->offset;
1258 				wLength = d->length;
1259 			}
1260 		} else if (dma) {
1261 			done = true;
1262 		} else {
1263 			/* see if we need to send more data, or ZLP */
1264 			if (qh->segsize < qh->maxpacket)
1265 				done = true;
1266 			else if (qh->offset == urb->transfer_buffer_length
1267 					&& !(urb->transfer_flags
1268 						& URB_ZERO_PACKET))
1269 				done = true;
1270 			if (!done) {
1271 				buf = urb->transfer_buffer
1272 						+ qh->offset;
1273 				wLength = urb->transfer_buffer_length
1274 						- qh->offset;
1275 			}
1276 		}
1277 	}
1278 
1279 	/* urb->status != -EINPROGRESS means request has been faulted,
1280 	 * so we must abort this transfer after cleanup
1281 	 */
1282 	if (urb->status != -EINPROGRESS) {
1283 		done = true;
1284 		if (status == 0)
1285 			status = urb->status;
1286 	}
1287 
1288 	if (done) {
1289 		/* set status */
1290 		urb->status = status;
1291 		urb->actual_length = qh->offset;
1292 		musb_advance_schedule(musb, urb, hw_ep, USB_DIR_OUT);
1293 
1294 	} else if (!(tx_csr & MUSB_TXCSR_DMAENAB)) {
1295 		/* WARN_ON(!buf); */
1296 
1297 		/* REVISIT:  some docs say that when hw_ep->tx_double_buffered,
1298 		 * (and presumably, fifo is not half-full) we should write TWO
1299 		 * packets before updating TXCSR ... other docs disagree ...
1300 		 */
1301 		/* PIO:  start next packet in this URB */
1302 		if (wLength > qh->maxpacket)
1303 			wLength = qh->maxpacket;
1304 		musb_write_fifo(hw_ep, wLength, buf);
1305 		qh->segsize = wLength;
1306 
1307 		musb_ep_select(mbase, epnum);
1308 		musb_writew(epio, MUSB_TXCSR,
1309 				MUSB_TXCSR_H_WZC_BITS | MUSB_TXCSR_TXPKTRDY);
1310 	} else
1311 		DBG(1, "not complete, but dma enabled?\n");
1312 
1313 finish:
1314 	return;
1315 }
1316 
1317 
1318 #ifdef CONFIG_USB_INVENTRA_DMA
1319 
1320 /* Host side RX (IN) using Mentor DMA works as follows:
1321 	submit_urb ->
1322 		- if queue was empty, ProgramEndpoint
1323 		- first IN token is sent out (by setting ReqPkt)
1324 	LinuxIsr -> RxReady()
1325 	/\	=> first packet is received
1326 	|	- Set in mode 0 (DmaEnab, ~ReqPkt)
1327 	|		-> DMA Isr (transfer complete) -> RxReady()
1328 	|		    - Ack receive (~RxPktRdy), turn off DMA (~DmaEnab)
1329 	|		    - if urb not complete, send next IN token (ReqPkt)
1330 	|			   |		else complete urb.
1331 	|			   |
1332 	---------------------------
1333  *
1334  * Nuances of mode 1:
1335  *	For short packets, no ack (+RxPktRdy) is sent automatically
1336  *	(even if AutoClear is ON)
1337  *	For full packets, ack (~RxPktRdy) and next IN token (+ReqPkt) is sent
1338  *	automatically => major problem, as collecting the next packet becomes
1339  *	difficult. Hence mode 1 is not used.
1340  *
1341  * REVISIT
1342  *	All we care about at this driver level is that
1343  *       (a) all URBs terminate with REQPKT cleared and fifo(s) empty;
1344  *       (b) termination conditions are: short RX, or buffer full;
1345  *       (c) fault modes include
1346  *           - iff URB_SHORT_NOT_OK, short RX status is -EREMOTEIO.
1347  *             (and that endpoint's dma queue stops immediately)
1348  *           - overflow (full, PLUS more bytes in the terminal packet)
1349  *
1350  *	So for example, usb-storage sets URB_SHORT_NOT_OK, and would
1351  *	thus be a great candidate for using mode 1 ... for all but the
1352  *	last packet of one URB's transfer.
1353  */
1354 
1355 #endif
1356 
1357 /* Schedule next QH from musb->in_bulk and move the current qh to
1358  * the end; avoids starvation for other endpoints.
1359  */
1360 static void musb_bulk_rx_nak_timeout(struct musb *musb, struct musb_hw_ep *ep)
1361 {
1362 	struct dma_channel	*dma;
1363 	struct urb		*urb;
1364 	void __iomem		*mbase = musb->mregs;
1365 	void __iomem		*epio = ep->regs;
1366 	struct musb_qh		*cur_qh, *next_qh;
1367 	u16			rx_csr;
1368 
1369 	musb_ep_select(mbase, ep->epnum);
1370 	dma = is_dma_capable() ? ep->rx_channel : NULL;
1371 
1372 	/* clear nak timeout bit */
1373 	rx_csr = musb_readw(epio, MUSB_RXCSR);
1374 	rx_csr |= MUSB_RXCSR_H_WZC_BITS;
1375 	rx_csr &= ~MUSB_RXCSR_DATAERROR;
1376 	musb_writew(epio, MUSB_RXCSR, rx_csr);
1377 
1378 	cur_qh = first_qh(&musb->in_bulk);
1379 	if (cur_qh) {
1380 		urb = next_urb(cur_qh);
1381 		if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1382 			dma->status = MUSB_DMA_STATUS_CORE_ABORT;
1383 			musb->dma_controller->channel_abort(dma);
1384 			urb->actual_length += dma->actual_len;
1385 			dma->actual_len = 0L;
1386 		}
1387 		musb_save_toggle(ep, 1, urb);
1388 
1389 		/* move cur_qh to end of queue */
1390 		list_move_tail(&cur_qh->ring, &musb->in_bulk);
1391 
1392 		/* get the next qh from musb->in_bulk */
1393 		next_qh = first_qh(&musb->in_bulk);
1394 
1395 		/* set rx_reinit and schedule the next qh */
1396 		ep->rx_reinit = 1;
1397 		musb_start_urb(musb, 1, next_qh);
1398 	}
1399 }
1400 
1401 /*
1402  * Service an RX interrupt for the given IN endpoint; docs cover bulk, iso,
1403  * and high-bandwidth IN transfer cases.
1404  */
1405 void musb_host_rx(struct musb *musb, u8 epnum)
1406 {
1407 	struct urb		*urb;
1408 	struct musb_hw_ep	*hw_ep = musb->endpoints + epnum;
1409 	void __iomem		*epio = hw_ep->regs;
1410 	struct musb_qh		*qh = hw_ep->in_qh;
1411 	size_t			xfer_len;
1412 	void __iomem		*mbase = musb->mregs;
1413 	int			pipe;
1414 	u16			rx_csr, val;
1415 	bool			iso_err = false;
1416 	bool			done = false;
1417 	u32			status;
1418 	struct dma_channel	*dma;
1419 
1420 	musb_ep_select(mbase, epnum);
1421 
1422 	urb = next_urb(qh);
1423 	dma = is_dma_capable() ? hw_ep->rx_channel : NULL;
1424 	status = 0;
1425 	xfer_len = 0;
1426 
1427 	rx_csr = musb_readw(epio, MUSB_RXCSR);
1428 	val = rx_csr;
1429 
1430 	if (unlikely(!urb)) {
1431 		/* REVISIT -- THIS SHOULD NEVER HAPPEN ... but, at least
1432 		 * usbtest #11 (unlinks) triggers it regularly, sometimes
1433 		 * with fifo full.  (Only with DMA??)
1434 		 */
1435 		DBG(3, "BOGUS RX%d ready, csr %04x, count %d\n", epnum, val,
1436 			musb_readw(epio, MUSB_RXCOUNT));
1437 		musb_h_flush_rxfifo(hw_ep, MUSB_RXCSR_CLRDATATOG);
1438 		return;
1439 	}
1440 
1441 	pipe = urb->pipe;
1442 
1443 	DBG(5, "<== hw %d rxcsr %04x, urb actual %d (+dma %zu)\n",
1444 		epnum, rx_csr, urb->actual_length,
1445 		dma ? dma->actual_len : 0);
1446 
1447 	/* check for errors, concurrent stall & unlink is not really
1448 	 * handled yet! */
1449 	if (rx_csr & MUSB_RXCSR_H_RXSTALL) {
1450 		DBG(3, "RX end %d STALL\n", epnum);
1451 
1452 		/* stall; record URB status */
1453 		status = -EPIPE;
1454 
1455 	} else if (rx_csr & MUSB_RXCSR_H_ERROR) {
1456 		DBG(3, "end %d RX proto error\n", epnum);
1457 
1458 		status = -EPROTO;
1459 		musb_writeb(epio, MUSB_RXINTERVAL, 0);
1460 
1461 	} else if (rx_csr & MUSB_RXCSR_DATAERROR) {
1462 
1463 		if (USB_ENDPOINT_XFER_ISOC != qh->type) {
1464 			DBG(6, "RX end %d NAK timeout\n", epnum);
1465 
1466 			/* NOTE: NAKing is *NOT* an error, so we want to
1467 			 * continue.  Except ... if there's a request for
1468 			 * another QH, use that instead of starving it.
1469 			 *
1470 			 * Devices like Ethernet and serial adapters keep
1471 			 * reads posted at all times, which will starve
1472 			 * other devices without this logic.
1473 			 */
1474 			if (usb_pipebulk(urb->pipe)
1475 					&& qh->mux == 1
1476 					&& !list_is_singular(&musb->in_bulk)) {
1477 				musb_bulk_rx_nak_timeout(musb, hw_ep);
1478 				return;
1479 			}
1480 			musb_ep_select(mbase, epnum);
1481 			rx_csr |= MUSB_RXCSR_H_WZC_BITS;
1482 			rx_csr &= ~MUSB_RXCSR_DATAERROR;
1483 			musb_writew(epio, MUSB_RXCSR, rx_csr);
1484 
1485 			goto finish;
1486 		} else {
1487 			DBG(4, "RX end %d ISO data error\n", epnum);
1488 			/* packet error reported later */
1489 			iso_err = true;
1490 		}
1491 	}
1492 
1493 	/* faults abort the transfer */
1494 	if (status) {
1495 		/* clean up dma and collect transfer count */
1496 		if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1497 			dma->status = MUSB_DMA_STATUS_CORE_ABORT;
1498 			(void) musb->dma_controller->channel_abort(dma);
1499 			xfer_len = dma->actual_len;
1500 		}
1501 		musb_h_flush_rxfifo(hw_ep, MUSB_RXCSR_CLRDATATOG);
1502 		musb_writeb(epio, MUSB_RXINTERVAL, 0);
1503 		done = true;
1504 		goto finish;
1505 	}
1506 
1507 	if (unlikely(dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY)) {
1508 		/* SHOULD NEVER HAPPEN ... but at least DaVinci has done it */
1509 		ERR("RX%d dma busy, csr %04x\n", epnum, rx_csr);
1510 		goto finish;
1511 	}
1512 
1513 	/* thorough shutdown for now ... given more precise fault handling
1514 	 * and better queueing support, we might keep a DMA pipeline going
1515 	 * while processing this irq for earlier completions.
1516 	 */
1517 
1518 	/* FIXME this is _way_ too much in-line logic for Mentor DMA */
1519 
1520 #ifndef CONFIG_USB_INVENTRA_DMA
1521 	if (rx_csr & MUSB_RXCSR_H_REQPKT)  {
1522 		/* REVISIT this happened for a while on some short reads...
1523 		 * the cleanup still needs investigation... looks bad...
1524 		 * and also duplicates dma cleanup code above ... plus,
1525 		 * shouldn't this be the "half full" double buffer case?
1526 		 */
1527 		if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1528 			dma->status = MUSB_DMA_STATUS_CORE_ABORT;
1529 			(void) musb->dma_controller->channel_abort(dma);
1530 			xfer_len = dma->actual_len;
1531 			done = true;
1532 		}
1533 
1534 		DBG(2, "RXCSR%d %04x, reqpkt, len %zu%s\n", epnum, rx_csr,
1535 				xfer_len, dma ? ", dma" : "");
1536 		rx_csr &= ~MUSB_RXCSR_H_REQPKT;
1537 
1538 		musb_ep_select(mbase, epnum);
1539 		musb_writew(epio, MUSB_RXCSR,
1540 				MUSB_RXCSR_H_WZC_BITS | rx_csr);
1541 	}
1542 #endif
1543 	if (dma && (rx_csr & MUSB_RXCSR_DMAENAB)) {
1544 		xfer_len = dma->actual_len;
1545 
1546 		val &= ~(MUSB_RXCSR_DMAENAB
1547 			| MUSB_RXCSR_H_AUTOREQ
1548 			| MUSB_RXCSR_AUTOCLEAR
1549 			| MUSB_RXCSR_RXPKTRDY);
1550 		musb_writew(hw_ep->regs, MUSB_RXCSR, val);
1551 
1552 #ifdef CONFIG_USB_INVENTRA_DMA
1553 		if (usb_pipeisoc(pipe)) {
1554 			struct usb_iso_packet_descriptor *d;
1555 
1556 			d = urb->iso_frame_desc + qh->iso_idx;
1557 			d->actual_length = xfer_len;
1558 
1559 			/* even if there was an error, we did the dma
1560 			 * for iso_frame_desc->length
1561 			 */
1562 			if (d->status != EILSEQ && d->status != -EOVERFLOW)
1563 				d->status = 0;
1564 
1565 			if (++qh->iso_idx >= urb->number_of_packets)
1566 				done = true;
1567 			else
1568 				done = false;
1569 
1570 		} else  {
1571 		/* done if urb buffer is full or short packet is recd */
1572 		done = (urb->actual_length + xfer_len >=
1573 				urb->transfer_buffer_length
1574 			|| dma->actual_len < qh->maxpacket);
1575 		}
1576 
1577 		/* send IN token for next packet, without AUTOREQ */
1578 		if (!done) {
1579 			val |= MUSB_RXCSR_H_REQPKT;
1580 			musb_writew(epio, MUSB_RXCSR,
1581 				MUSB_RXCSR_H_WZC_BITS | val);
1582 		}
1583 
1584 		DBG(4, "ep %d dma %s, rxcsr %04x, rxcount %d\n", epnum,
1585 			done ? "off" : "reset",
1586 			musb_readw(epio, MUSB_RXCSR),
1587 			musb_readw(epio, MUSB_RXCOUNT));
1588 #else
1589 		done = true;
1590 #endif
1591 	} else if (urb->status == -EINPROGRESS) {
1592 		/* if no errors, be sure a packet is ready for unloading */
1593 		if (unlikely(!(rx_csr & MUSB_RXCSR_RXPKTRDY))) {
1594 			status = -EPROTO;
1595 			ERR("Rx interrupt with no errors or packet!\n");
1596 
1597 			/* FIXME this is another "SHOULD NEVER HAPPEN" */
1598 
1599 /* SCRUB (RX) */
1600 			/* do the proper sequence to abort the transfer */
1601 			musb_ep_select(mbase, epnum);
1602 			val &= ~MUSB_RXCSR_H_REQPKT;
1603 			musb_writew(epio, MUSB_RXCSR, val);
1604 			goto finish;
1605 		}
1606 
1607 		/* we are expecting IN packets */
1608 #ifdef CONFIG_USB_INVENTRA_DMA
1609 		if (dma) {
1610 			struct dma_controller	*c;
1611 			u16			rx_count;
1612 			int			ret, length;
1613 			dma_addr_t		buf;
1614 
1615 			rx_count = musb_readw(epio, MUSB_RXCOUNT);
1616 
1617 			DBG(2, "RX%d count %d, buffer 0x%x len %d/%d\n",
1618 					epnum, rx_count,
1619 					urb->transfer_dma
1620 						+ urb->actual_length,
1621 					qh->offset,
1622 					urb->transfer_buffer_length);
1623 
1624 			c = musb->dma_controller;
1625 
1626 			if (usb_pipeisoc(pipe)) {
1627 				int status = 0;
1628 				struct usb_iso_packet_descriptor *d;
1629 
1630 				d = urb->iso_frame_desc + qh->iso_idx;
1631 
1632 				if (iso_err) {
1633 					status = -EILSEQ;
1634 					urb->error_count++;
1635 				}
1636 				if (rx_count > d->length) {
1637 					if (status == 0) {
1638 						status = -EOVERFLOW;
1639 						urb->error_count++;
1640 					}
1641 					DBG(2, "** OVERFLOW %d into %d\n",\
1642 					    rx_count, d->length);
1643 
1644 					length = d->length;
1645 				} else
1646 					length = rx_count;
1647 				d->status = status;
1648 				buf = urb->transfer_dma + d->offset;
1649 			} else {
1650 				length = rx_count;
1651 				buf = urb->transfer_dma +
1652 						urb->actual_length;
1653 			}
1654 
1655 			dma->desired_mode = 0;
1656 #ifdef USE_MODE1
1657 			/* because of the issue below, mode 1 will
1658 			 * only rarely behave with correct semantics.
1659 			 */
1660 			if ((urb->transfer_flags &
1661 						URB_SHORT_NOT_OK)
1662 				&& (urb->transfer_buffer_length -
1663 						urb->actual_length)
1664 					> qh->maxpacket)
1665 				dma->desired_mode = 1;
1666 			if (rx_count < hw_ep->max_packet_sz_rx) {
1667 				length = rx_count;
1668 				dma->bDesiredMode = 0;
1669 			} else {
1670 				length = urb->transfer_buffer_length;
1671 			}
1672 #endif
1673 
1674 /* Disadvantage of using mode 1:
1675  *	It's basically usable only for mass storage class; essentially all
1676  *	other protocols also terminate transfers on short packets.
1677  *
1678  * Details:
1679  *	An extra IN token is sent at the end of the transfer (due to AUTOREQ)
1680  *	If you try to use mode 1 for (transfer_buffer_length - 512), and try
1681  *	to use the extra IN token to grab the last packet using mode 0, then
1682  *	the problem is that you cannot be sure when the device will send the
1683  *	last packet and RxPktRdy set. Sometimes the packet is recd too soon
1684  *	such that it gets lost when RxCSR is re-set at the end of the mode 1
1685  *	transfer, while sometimes it is recd just a little late so that if you
1686  *	try to configure for mode 0 soon after the mode 1 transfer is
1687  *	completed, you will find rxcount 0. Okay, so you might think why not
1688  *	wait for an interrupt when the pkt is recd. Well, you won't get any!
1689  */
1690 
1691 			val = musb_readw(epio, MUSB_RXCSR);
1692 			val &= ~MUSB_RXCSR_H_REQPKT;
1693 
1694 			if (dma->desired_mode == 0)
1695 				val &= ~MUSB_RXCSR_H_AUTOREQ;
1696 			else
1697 				val |= MUSB_RXCSR_H_AUTOREQ;
1698 			val |= MUSB_RXCSR_AUTOCLEAR | MUSB_RXCSR_DMAENAB;
1699 
1700 			musb_writew(epio, MUSB_RXCSR,
1701 				MUSB_RXCSR_H_WZC_BITS | val);
1702 
1703 			/* REVISIT if when actual_length != 0,
1704 			 * transfer_buffer_length needs to be
1705 			 * adjusted first...
1706 			 */
1707 			ret = c->channel_program(
1708 				dma, qh->maxpacket,
1709 				dma->desired_mode, buf, length);
1710 
1711 			if (!ret) {
1712 				c->channel_release(dma);
1713 				hw_ep->rx_channel = NULL;
1714 				dma = NULL;
1715 				/* REVISIT reset CSR */
1716 			}
1717 		}
1718 #endif	/* Mentor DMA */
1719 
1720 		if (!dma) {
1721 			done = musb_host_packet_rx(musb, urb,
1722 					epnum, iso_err);
1723 			DBG(6, "read %spacket\n", done ? "last " : "");
1724 		}
1725 	}
1726 
1727 finish:
1728 	urb->actual_length += xfer_len;
1729 	qh->offset += xfer_len;
1730 	if (done) {
1731 		if (urb->status == -EINPROGRESS)
1732 			urb->status = status;
1733 		musb_advance_schedule(musb, urb, hw_ep, USB_DIR_IN);
1734 	}
1735 }
1736 
1737 /* schedule nodes correspond to peripheral endpoints, like an OHCI QH.
1738  * the software schedule associates multiple such nodes with a given
1739  * host side hardware endpoint + direction; scheduling may activate
1740  * that hardware endpoint.
1741  */
1742 static int musb_schedule(
1743 	struct musb		*musb,
1744 	struct musb_qh		*qh,
1745 	int			is_in)
1746 {
1747 	int			idle;
1748 	int			best_diff;
1749 	int			best_end, epnum;
1750 	struct musb_hw_ep	*hw_ep = NULL;
1751 	struct list_head	*head = NULL;
1752 
1753 	/* use fixed hardware for control and bulk */
1754 	if (qh->type == USB_ENDPOINT_XFER_CONTROL) {
1755 		head = &musb->control;
1756 		hw_ep = musb->control_ep;
1757 		goto success;
1758 	}
1759 
1760 	/* else, periodic transfers get muxed to other endpoints */
1761 
1762 	/*
1763 	 * We know this qh hasn't been scheduled, so all we need to do
1764 	 * is choose which hardware endpoint to put it on ...
1765 	 *
1766 	 * REVISIT what we really want here is a regular schedule tree
1767 	 * like e.g. OHCI uses.
1768 	 */
1769 	best_diff = 4096;
1770 	best_end = -1;
1771 
1772 	for (epnum = 1, hw_ep = musb->endpoints + 1;
1773 			epnum < musb->nr_endpoints;
1774 			epnum++, hw_ep++) {
1775 		int	diff;
1776 
1777 		if (is_in || hw_ep->is_shared_fifo) {
1778 			if (hw_ep->in_qh  != NULL)
1779 				continue;
1780 		} else	if (hw_ep->out_qh != NULL)
1781 			continue;
1782 
1783 		if (hw_ep == musb->bulk_ep)
1784 			continue;
1785 
1786 		if (is_in)
1787 			diff = hw_ep->max_packet_sz_rx - qh->maxpacket;
1788 		else
1789 			diff = hw_ep->max_packet_sz_tx - qh->maxpacket;
1790 
1791 		if (diff >= 0 && best_diff > diff) {
1792 			best_diff = diff;
1793 			best_end = epnum;
1794 		}
1795 	}
1796 	/* use bulk reserved ep1 if no other ep is free */
1797 	if (best_end < 0 && qh->type == USB_ENDPOINT_XFER_BULK) {
1798 		hw_ep = musb->bulk_ep;
1799 		if (is_in)
1800 			head = &musb->in_bulk;
1801 		else
1802 			head = &musb->out_bulk;
1803 
1804 		/* Enable bulk RX NAK timeout scheme when bulk requests are
1805 		 * multiplexed.  This scheme doen't work in high speed to full
1806 		 * speed scenario as NAK interrupts are not coming from a
1807 		 * full speed device connected to a high speed device.
1808 		 * NAK timeout interval is 8 (128 uframe or 16ms) for HS and
1809 		 * 4 (8 frame or 8ms) for FS device.
1810 		 */
1811 		if (is_in && qh->dev)
1812 			qh->intv_reg =
1813 				(USB_SPEED_HIGH == qh->dev->speed) ? 8 : 4;
1814 		goto success;
1815 	} else if (best_end < 0) {
1816 		return -ENOSPC;
1817 	}
1818 
1819 	idle = 1;
1820 	qh->mux = 0;
1821 	hw_ep = musb->endpoints + best_end;
1822 	DBG(4, "qh %p periodic slot %d\n", qh, best_end);
1823 success:
1824 	if (head) {
1825 		idle = list_empty(head);
1826 		list_add_tail(&qh->ring, head);
1827 		qh->mux = 1;
1828 	}
1829 	qh->hw_ep = hw_ep;
1830 	qh->hep->hcpriv = qh;
1831 	if (idle)
1832 		musb_start_urb(musb, is_in, qh);
1833 	return 0;
1834 }
1835 
1836 static int musb_urb_enqueue(
1837 	struct usb_hcd			*hcd,
1838 	struct urb			*urb,
1839 	gfp_t				mem_flags)
1840 {
1841 	unsigned long			flags;
1842 	struct musb			*musb = hcd_to_musb(hcd);
1843 	struct usb_host_endpoint	*hep = urb->ep;
1844 	struct musb_qh			*qh = hep->hcpriv;
1845 	struct usb_endpoint_descriptor	*epd = &hep->desc;
1846 	int				ret;
1847 	unsigned			type_reg;
1848 	unsigned			interval;
1849 
1850 	/* host role must be active */
1851 	if (!is_host_active(musb) || !musb->is_active)
1852 		return -ENODEV;
1853 
1854 	spin_lock_irqsave(&musb->lock, flags);
1855 	ret = usb_hcd_link_urb_to_ep(hcd, urb);
1856 	spin_unlock_irqrestore(&musb->lock, flags);
1857 	if (ret)
1858 		return ret;
1859 
1860 	/* DMA mapping was already done, if needed, and this urb is on
1861 	 * hep->urb_list ... so there's little to do unless hep wasn't
1862 	 * yet scheduled onto a live qh.
1863 	 *
1864 	 * REVISIT best to keep hep->hcpriv valid until the endpoint gets
1865 	 * disabled, testing for empty qh->ring and avoiding qh setup costs
1866 	 * except for the first urb queued after a config change.
1867 	 */
1868 	if (qh) {
1869 		urb->hcpriv = qh;
1870 		return 0;
1871 	}
1872 
1873 	/* Allocate and initialize qh, minimizing the work done each time
1874 	 * hw_ep gets reprogrammed, or with irqs blocked.  Then schedule it.
1875 	 *
1876 	 * REVISIT consider a dedicated qh kmem_cache, so it's harder
1877 	 * for bugs in other kernel code to break this driver...
1878 	 */
1879 	qh = kzalloc(sizeof *qh, mem_flags);
1880 	if (!qh) {
1881 		spin_lock_irqsave(&musb->lock, flags);
1882 		usb_hcd_unlink_urb_from_ep(hcd, urb);
1883 		spin_unlock_irqrestore(&musb->lock, flags);
1884 		return -ENOMEM;
1885 	}
1886 
1887 	qh->hep = hep;
1888 	qh->dev = urb->dev;
1889 	INIT_LIST_HEAD(&qh->ring);
1890 	qh->is_ready = 1;
1891 
1892 	qh->maxpacket = le16_to_cpu(epd->wMaxPacketSize);
1893 
1894 	/* no high bandwidth support yet */
1895 	if (qh->maxpacket & ~0x7ff) {
1896 		ret = -EMSGSIZE;
1897 		goto done;
1898 	}
1899 
1900 	qh->epnum = usb_endpoint_num(epd);
1901 	qh->type = usb_endpoint_type(epd);
1902 
1903 	/* NOTE: urb->dev->devnum is wrong during SET_ADDRESS */
1904 	qh->addr_reg = (u8) usb_pipedevice(urb->pipe);
1905 
1906 	/* precompute rxtype/txtype/type0 register */
1907 	type_reg = (qh->type << 4) | qh->epnum;
1908 	switch (urb->dev->speed) {
1909 	case USB_SPEED_LOW:
1910 		type_reg |= 0xc0;
1911 		break;
1912 	case USB_SPEED_FULL:
1913 		type_reg |= 0x80;
1914 		break;
1915 	default:
1916 		type_reg |= 0x40;
1917 	}
1918 	qh->type_reg = type_reg;
1919 
1920 	/* Precompute RXINTERVAL/TXINTERVAL register */
1921 	switch (qh->type) {
1922 	case USB_ENDPOINT_XFER_INT:
1923 		/*
1924 		 * Full/low speeds use the  linear encoding,
1925 		 * high speed uses the logarithmic encoding.
1926 		 */
1927 		if (urb->dev->speed <= USB_SPEED_FULL) {
1928 			interval = max_t(u8, epd->bInterval, 1);
1929 			break;
1930 		}
1931 		/* FALLTHROUGH */
1932 	case USB_ENDPOINT_XFER_ISOC:
1933 		/* ISO always uses logarithmic encoding */
1934 		interval = min_t(u8, epd->bInterval, 16);
1935 		break;
1936 	default:
1937 		/* REVISIT we actually want to use NAK limits, hinting to the
1938 		 * transfer scheduling logic to try some other qh, e.g. try
1939 		 * for 2 msec first:
1940 		 *
1941 		 * interval = (USB_SPEED_HIGH == urb->dev->speed) ? 16 : 2;
1942 		 *
1943 		 * The downside of disabling this is that transfer scheduling
1944 		 * gets VERY unfair for nonperiodic transfers; a misbehaving
1945 		 * peripheral could make that hurt.  That's perfectly normal
1946 		 * for reads from network or serial adapters ... so we have
1947 		 * partial NAKlimit support for bulk RX.
1948 		 *
1949 		 * The upside of disabling it is simpler transfer scheduling.
1950 		 */
1951 		interval = 0;
1952 	}
1953 	qh->intv_reg = interval;
1954 
1955 	/* precompute addressing for external hub/tt ports */
1956 	if (musb->is_multipoint) {
1957 		struct usb_device	*parent = urb->dev->parent;
1958 
1959 		if (parent != hcd->self.root_hub) {
1960 			qh->h_addr_reg = (u8) parent->devnum;
1961 
1962 			/* set up tt info if needed */
1963 			if (urb->dev->tt) {
1964 				qh->h_port_reg = (u8) urb->dev->ttport;
1965 				if (urb->dev->tt->hub)
1966 					qh->h_addr_reg =
1967 						(u8) urb->dev->tt->hub->devnum;
1968 				if (urb->dev->tt->multi)
1969 					qh->h_addr_reg |= 0x80;
1970 			}
1971 		}
1972 	}
1973 
1974 	/* invariant: hep->hcpriv is null OR the qh that's already scheduled.
1975 	 * until we get real dma queues (with an entry for each urb/buffer),
1976 	 * we only have work to do in the former case.
1977 	 */
1978 	spin_lock_irqsave(&musb->lock, flags);
1979 	if (hep->hcpriv) {
1980 		/* some concurrent activity submitted another urb to hep...
1981 		 * odd, rare, error prone, but legal.
1982 		 */
1983 		kfree(qh);
1984 		ret = 0;
1985 	} else
1986 		ret = musb_schedule(musb, qh,
1987 				epd->bEndpointAddress & USB_ENDPOINT_DIR_MASK);
1988 
1989 	if (ret == 0) {
1990 		urb->hcpriv = qh;
1991 		/* FIXME set urb->start_frame for iso/intr, it's tested in
1992 		 * musb_start_urb(), but otherwise only konicawc cares ...
1993 		 */
1994 	}
1995 	spin_unlock_irqrestore(&musb->lock, flags);
1996 
1997 done:
1998 	if (ret != 0) {
1999 		spin_lock_irqsave(&musb->lock, flags);
2000 		usb_hcd_unlink_urb_from_ep(hcd, urb);
2001 		spin_unlock_irqrestore(&musb->lock, flags);
2002 		kfree(qh);
2003 	}
2004 	return ret;
2005 }
2006 
2007 
2008 /*
2009  * abort a transfer that's at the head of a hardware queue.
2010  * called with controller locked, irqs blocked
2011  * that hardware queue advances to the next transfer, unless prevented
2012  */
2013 static int musb_cleanup_urb(struct urb *urb, struct musb_qh *qh, int is_in)
2014 {
2015 	struct musb_hw_ep	*ep = qh->hw_ep;
2016 	void __iomem		*epio = ep->regs;
2017 	unsigned		hw_end = ep->epnum;
2018 	void __iomem		*regs = ep->musb->mregs;
2019 	u16			csr;
2020 	int			status = 0;
2021 
2022 	musb_ep_select(regs, hw_end);
2023 
2024 	if (is_dma_capable()) {
2025 		struct dma_channel	*dma;
2026 
2027 		dma = is_in ? ep->rx_channel : ep->tx_channel;
2028 		if (dma) {
2029 			status = ep->musb->dma_controller->channel_abort(dma);
2030 			DBG(status ? 1 : 3,
2031 				"abort %cX%d DMA for urb %p --> %d\n",
2032 				is_in ? 'R' : 'T', ep->epnum,
2033 				urb, status);
2034 			urb->actual_length += dma->actual_len;
2035 		}
2036 	}
2037 
2038 	/* turn off DMA requests, discard state, stop polling ... */
2039 	if (is_in) {
2040 		/* giveback saves bulk toggle */
2041 		csr = musb_h_flush_rxfifo(ep, 0);
2042 
2043 		/* REVISIT we still get an irq; should likely clear the
2044 		 * endpoint's irq status here to avoid bogus irqs.
2045 		 * clearing that status is platform-specific...
2046 		 */
2047 	} else {
2048 		musb_h_tx_flush_fifo(ep);
2049 		csr = musb_readw(epio, MUSB_TXCSR);
2050 		csr &= ~(MUSB_TXCSR_AUTOSET
2051 			| MUSB_TXCSR_DMAENAB
2052 			| MUSB_TXCSR_H_RXSTALL
2053 			| MUSB_TXCSR_H_NAKTIMEOUT
2054 			| MUSB_TXCSR_H_ERROR
2055 			| MUSB_TXCSR_TXPKTRDY);
2056 		musb_writew(epio, MUSB_TXCSR, csr);
2057 		/* REVISIT may need to clear FLUSHFIFO ... */
2058 		musb_writew(epio, MUSB_TXCSR, csr);
2059 		/* flush cpu writebuffer */
2060 		csr = musb_readw(epio, MUSB_TXCSR);
2061 	}
2062 	if (status == 0)
2063 		musb_advance_schedule(ep->musb, urb, ep, is_in);
2064 	return status;
2065 }
2066 
2067 static int musb_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
2068 {
2069 	struct musb		*musb = hcd_to_musb(hcd);
2070 	struct musb_qh		*qh;
2071 	struct list_head	*sched;
2072 	unsigned long		flags;
2073 	int			ret;
2074 
2075 	DBG(4, "urb=%p, dev%d ep%d%s\n", urb,
2076 			usb_pipedevice(urb->pipe),
2077 			usb_pipeendpoint(urb->pipe),
2078 			usb_pipein(urb->pipe) ? "in" : "out");
2079 
2080 	spin_lock_irqsave(&musb->lock, flags);
2081 	ret = usb_hcd_check_unlink_urb(hcd, urb, status);
2082 	if (ret)
2083 		goto done;
2084 
2085 	qh = urb->hcpriv;
2086 	if (!qh)
2087 		goto done;
2088 
2089 	/* Any URB not actively programmed into endpoint hardware can be
2090 	 * immediately given back; that's any URB not at the head of an
2091 	 * endpoint queue, unless someday we get real DMA queues.  And even
2092 	 * if it's at the head, it might not be known to the hardware...
2093 	 *
2094 	 * Otherwise abort current transfer, pending dma, etc.; urb->status
2095 	 * has already been updated.  This is a synchronous abort; it'd be
2096 	 * OK to hold off until after some IRQ, though.
2097 	 */
2098 	if (!qh->is_ready || urb->urb_list.prev != &qh->hep->urb_list)
2099 		ret = -EINPROGRESS;
2100 	else {
2101 		switch (qh->type) {
2102 		case USB_ENDPOINT_XFER_CONTROL:
2103 			sched = &musb->control;
2104 			break;
2105 		case USB_ENDPOINT_XFER_BULK:
2106 			if (qh->mux == 1) {
2107 				if (usb_pipein(urb->pipe))
2108 					sched = &musb->in_bulk;
2109 				else
2110 					sched = &musb->out_bulk;
2111 				break;
2112 			}
2113 		default:
2114 			/* REVISIT when we get a schedule tree, periodic
2115 			 * transfers won't always be at the head of a
2116 			 * singleton queue...
2117 			 */
2118 			sched = NULL;
2119 			break;
2120 		}
2121 	}
2122 
2123 	/* NOTE:  qh is invalid unless !list_empty(&hep->urb_list) */
2124 	if (ret < 0 || (sched && qh != first_qh(sched))) {
2125 		int	ready = qh->is_ready;
2126 
2127 		ret = 0;
2128 		qh->is_ready = 0;
2129 		__musb_giveback(musb, urb, 0);
2130 		qh->is_ready = ready;
2131 
2132 		/* If nothing else (usually musb_giveback) is using it
2133 		 * and its URB list has emptied, recycle this qh.
2134 		 */
2135 		if (ready && list_empty(&qh->hep->urb_list)) {
2136 			qh->hep->hcpriv = NULL;
2137 			list_del(&qh->ring);
2138 			kfree(qh);
2139 		}
2140 	} else
2141 		ret = musb_cleanup_urb(urb, qh, urb->pipe & USB_DIR_IN);
2142 done:
2143 	spin_unlock_irqrestore(&musb->lock, flags);
2144 	return ret;
2145 }
2146 
2147 /* disable an endpoint */
2148 static void
2149 musb_h_disable(struct usb_hcd *hcd, struct usb_host_endpoint *hep)
2150 {
2151 	u8			epnum = hep->desc.bEndpointAddress;
2152 	unsigned long		flags;
2153 	struct musb		*musb = hcd_to_musb(hcd);
2154 	u8			is_in = epnum & USB_DIR_IN;
2155 	struct musb_qh		*qh;
2156 	struct urb		*urb;
2157 	struct list_head	*sched;
2158 
2159 	spin_lock_irqsave(&musb->lock, flags);
2160 
2161 	qh = hep->hcpriv;
2162 	if (qh == NULL)
2163 		goto exit;
2164 
2165 	switch (qh->type) {
2166 	case USB_ENDPOINT_XFER_CONTROL:
2167 		sched = &musb->control;
2168 		break;
2169 	case USB_ENDPOINT_XFER_BULK:
2170 		if (qh->mux == 1) {
2171 			if (is_in)
2172 				sched = &musb->in_bulk;
2173 			else
2174 				sched = &musb->out_bulk;
2175 			break;
2176 		}
2177 	default:
2178 		/* REVISIT when we get a schedule tree, periodic transfers
2179 		 * won't always be at the head of a singleton queue...
2180 		 */
2181 		sched = NULL;
2182 		break;
2183 	}
2184 
2185 	/* NOTE:  qh is invalid unless !list_empty(&hep->urb_list) */
2186 
2187 	/* kick first urb off the hardware, if needed */
2188 	qh->is_ready = 0;
2189 	if (!sched || qh == first_qh(sched)) {
2190 		urb = next_urb(qh);
2191 
2192 		/* make software (then hardware) stop ASAP */
2193 		if (!urb->unlinked)
2194 			urb->status = -ESHUTDOWN;
2195 
2196 		/* cleanup */
2197 		musb_cleanup_urb(urb, qh, urb->pipe & USB_DIR_IN);
2198 
2199 		/* Then nuke all the others ... and advance the
2200 		 * queue on hw_ep (e.g. bulk ring) when we're done.
2201 		 */
2202 		while (!list_empty(&hep->urb_list)) {
2203 			urb = next_urb(qh);
2204 			urb->status = -ESHUTDOWN;
2205 			musb_advance_schedule(musb, urb, qh->hw_ep, is_in);
2206 		}
2207 	} else {
2208 		/* Just empty the queue; the hardware is busy with
2209 		 * other transfers, and since !qh->is_ready nothing
2210 		 * will activate any of these as it advances.
2211 		 */
2212 		while (!list_empty(&hep->urb_list))
2213 			__musb_giveback(musb, next_urb(qh), -ESHUTDOWN);
2214 
2215 		hep->hcpriv = NULL;
2216 		list_del(&qh->ring);
2217 		kfree(qh);
2218 	}
2219 exit:
2220 	spin_unlock_irqrestore(&musb->lock, flags);
2221 }
2222 
2223 static int musb_h_get_frame_number(struct usb_hcd *hcd)
2224 {
2225 	struct musb	*musb = hcd_to_musb(hcd);
2226 
2227 	return musb_readw(musb->mregs, MUSB_FRAME);
2228 }
2229 
2230 static int musb_h_start(struct usb_hcd *hcd)
2231 {
2232 	struct musb	*musb = hcd_to_musb(hcd);
2233 
2234 	/* NOTE: musb_start() is called when the hub driver turns
2235 	 * on port power, or when (OTG) peripheral starts.
2236 	 */
2237 	hcd->state = HC_STATE_RUNNING;
2238 	musb->port1_status = 0;
2239 	return 0;
2240 }
2241 
2242 static void musb_h_stop(struct usb_hcd *hcd)
2243 {
2244 	musb_stop(hcd_to_musb(hcd));
2245 	hcd->state = HC_STATE_HALT;
2246 }
2247 
2248 static int musb_bus_suspend(struct usb_hcd *hcd)
2249 {
2250 	struct musb	*musb = hcd_to_musb(hcd);
2251 
2252 	if (musb->xceiv.state == OTG_STATE_A_SUSPEND)
2253 		return 0;
2254 
2255 	if (is_host_active(musb) && musb->is_active) {
2256 		WARNING("trying to suspend as %s is_active=%i\n",
2257 			otg_state_string(musb), musb->is_active);
2258 		return -EBUSY;
2259 	} else
2260 		return 0;
2261 }
2262 
2263 static int musb_bus_resume(struct usb_hcd *hcd)
2264 {
2265 	/* resuming child port does the work */
2266 	return 0;
2267 }
2268 
2269 const struct hc_driver musb_hc_driver = {
2270 	.description		= "musb-hcd",
2271 	.product_desc		= "MUSB HDRC host driver",
2272 	.hcd_priv_size		= sizeof(struct musb),
2273 	.flags			= HCD_USB2 | HCD_MEMORY,
2274 
2275 	/* not using irq handler or reset hooks from usbcore, since
2276 	 * those must be shared with peripheral code for OTG configs
2277 	 */
2278 
2279 	.start			= musb_h_start,
2280 	.stop			= musb_h_stop,
2281 
2282 	.get_frame_number	= musb_h_get_frame_number,
2283 
2284 	.urb_enqueue		= musb_urb_enqueue,
2285 	.urb_dequeue		= musb_urb_dequeue,
2286 	.endpoint_disable	= musb_h_disable,
2287 
2288 	.hub_status_data	= musb_hub_status_data,
2289 	.hub_control		= musb_hub_control,
2290 	.bus_suspend		= musb_bus_suspend,
2291 	.bus_resume		= musb_bus_resume,
2292 	/* .start_port_reset	= NULL, */
2293 	/* .hub_irq_enable	= NULL, */
2294 };
2295