xref: /openbmc/linux/drivers/usb/musb/musb_host.c (revision 4dc7ccf7)
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 
45 #include "musb_core.h"
46 #include "musb_host.h"
47 
48 
49 /* MUSB HOST status 22-mar-2006
50  *
51  * - There's still lots of partial code duplication for fault paths, so
52  *   they aren't handled as consistently as they need to be.
53  *
54  * - PIO mostly behaved when last tested.
55  *     + including ep0, with all usbtest cases 9, 10
56  *     + usbtest 14 (ep0out) doesn't seem to run at all
57  *     + double buffered OUT/TX endpoints saw stalls(!) with certain usbtest
58  *       configurations, but otherwise double buffering passes basic tests.
59  *     + for 2.6.N, for N > ~10, needs API changes for hcd framework.
60  *
61  * - DMA (CPPI) ... partially behaves, not currently recommended
62  *     + about 1/15 the speed of typical EHCI implementations (PCI)
63  *     + RX, all too often reqpkt seems to misbehave after tx
64  *     + TX, no known issues (other than evident silicon issue)
65  *
66  * - DMA (Mentor/OMAP) ...has at least toggle update problems
67  *
68  * - [23-feb-2009] minimal traffic scheduling to avoid bulk RX packet
69  *   starvation ... nothing yet for TX, interrupt, or bulk.
70  *
71  * - Not tested with HNP, but some SRP paths seem to behave.
72  *
73  * NOTE 24-August-2006:
74  *
75  * - Bulk traffic finally uses both sides of hardware ep1, freeing up an
76  *   extra endpoint for periodic use enabling hub + keybd + mouse.  That
77  *   mostly works, except that with "usbnet" it's easy to trigger cases
78  *   with "ping" where RX loses.  (a) ping to davinci, even "ping -f",
79  *   fine; but (b) ping _from_ davinci, even "ping -c 1", ICMP RX loses
80  *   although ARP RX wins.  (That test was done with a full speed link.)
81  */
82 
83 
84 /*
85  * NOTE on endpoint usage:
86  *
87  * CONTROL transfers all go through ep0.  BULK ones go through dedicated IN
88  * and OUT endpoints ... hardware is dedicated for those "async" queue(s).
89  * (Yes, bulk _could_ use more of the endpoints than that, and would even
90  * benefit from it.)
91  *
92  * INTERUPPT and ISOCHRONOUS transfers are scheduled to the other endpoints.
93  * So far that scheduling is both dumb and optimistic:  the endpoint will be
94  * "claimed" until its software queue is no longer refilled.  No multiplexing
95  * of transfers between endpoints, or anything clever.
96  */
97 
98 
99 static void musb_ep_program(struct musb *musb, u8 epnum,
100 			struct urb *urb, int is_out,
101 			u8 *buf, u32 offset, u32 len);
102 
103 /*
104  * Clear TX fifo. Needed to avoid BABBLE errors.
105  */
106 static void musb_h_tx_flush_fifo(struct musb_hw_ep *ep)
107 {
108 	void __iomem	*epio = ep->regs;
109 	u16		csr;
110 	u16		lastcsr = 0;
111 	int		retries = 1000;
112 
113 	csr = musb_readw(epio, MUSB_TXCSR);
114 	while (csr & MUSB_TXCSR_FIFONOTEMPTY) {
115 		if (csr != lastcsr)
116 			DBG(3, "Host TX FIFONOTEMPTY csr: %02x\n", csr);
117 		lastcsr = csr;
118 		csr |= MUSB_TXCSR_FLUSHFIFO;
119 		musb_writew(epio, MUSB_TXCSR, csr);
120 		csr = musb_readw(epio, MUSB_TXCSR);
121 		if (WARN(retries-- < 1,
122 				"Could not flush host TX%d fifo: csr: %04x\n",
123 				ep->epnum, csr))
124 			return;
125 		mdelay(1);
126 	}
127 }
128 
129 static void musb_h_ep0_flush_fifo(struct musb_hw_ep *ep)
130 {
131 	void __iomem	*epio = ep->regs;
132 	u16		csr;
133 	int		retries = 5;
134 
135 	/* scrub any data left in the fifo */
136 	do {
137 		csr = musb_readw(epio, MUSB_TXCSR);
138 		if (!(csr & (MUSB_CSR0_TXPKTRDY | MUSB_CSR0_RXPKTRDY)))
139 			break;
140 		musb_writew(epio, MUSB_TXCSR, MUSB_CSR0_FLUSHFIFO);
141 		csr = musb_readw(epio, MUSB_TXCSR);
142 		udelay(10);
143 	} while (--retries);
144 
145 	WARN(!retries, "Could not flush host TX%d fifo: csr: %04x\n",
146 			ep->epnum, csr);
147 
148 	/* and reset for the next transfer */
149 	musb_writew(epio, MUSB_TXCSR, 0);
150 }
151 
152 /*
153  * Start transmit. Caller is responsible for locking shared resources.
154  * musb must be locked.
155  */
156 static inline void musb_h_tx_start(struct musb_hw_ep *ep)
157 {
158 	u16	txcsr;
159 
160 	/* NOTE: no locks here; caller should lock and select EP */
161 	if (ep->epnum) {
162 		txcsr = musb_readw(ep->regs, MUSB_TXCSR);
163 		txcsr |= MUSB_TXCSR_TXPKTRDY | MUSB_TXCSR_H_WZC_BITS;
164 		musb_writew(ep->regs, MUSB_TXCSR, txcsr);
165 	} else {
166 		txcsr = MUSB_CSR0_H_SETUPPKT | MUSB_CSR0_TXPKTRDY;
167 		musb_writew(ep->regs, MUSB_CSR0, txcsr);
168 	}
169 
170 }
171 
172 static inline void musb_h_tx_dma_start(struct musb_hw_ep *ep)
173 {
174 	u16	txcsr;
175 
176 	/* NOTE: no locks here; caller should lock and select EP */
177 	txcsr = musb_readw(ep->regs, MUSB_TXCSR);
178 	txcsr |= MUSB_TXCSR_DMAENAB | MUSB_TXCSR_H_WZC_BITS;
179 	if (is_cppi_enabled())
180 		txcsr |= MUSB_TXCSR_DMAMODE;
181 	musb_writew(ep->regs, MUSB_TXCSR, txcsr);
182 }
183 
184 static void musb_ep_set_qh(struct musb_hw_ep *ep, int is_in, struct musb_qh *qh)
185 {
186 	if (is_in != 0 || ep->is_shared_fifo)
187 		ep->in_qh  = qh;
188 	if (is_in == 0 || ep->is_shared_fifo)
189 		ep->out_qh = qh;
190 }
191 
192 static struct musb_qh *musb_ep_get_qh(struct musb_hw_ep *ep, int is_in)
193 {
194 	return is_in ? ep->in_qh : ep->out_qh;
195 }
196 
197 /*
198  * Start the URB at the front of an endpoint's queue
199  * end must be claimed from the caller.
200  *
201  * Context: controller locked, irqs blocked
202  */
203 static void
204 musb_start_urb(struct musb *musb, int is_in, struct musb_qh *qh)
205 {
206 	u16			frame;
207 	u32			len;
208 	void __iomem		*mbase =  musb->mregs;
209 	struct urb		*urb = next_urb(qh);
210 	void			*buf = urb->transfer_buffer;
211 	u32			offset = 0;
212 	struct musb_hw_ep	*hw_ep = qh->hw_ep;
213 	unsigned		pipe = urb->pipe;
214 	u8			address = usb_pipedevice(pipe);
215 	int			epnum = hw_ep->epnum;
216 
217 	/* initialize software qh state */
218 	qh->offset = 0;
219 	qh->segsize = 0;
220 
221 	/* gather right source of data */
222 	switch (qh->type) {
223 	case USB_ENDPOINT_XFER_CONTROL:
224 		/* control transfers always start with SETUP */
225 		is_in = 0;
226 		musb->ep0_stage = MUSB_EP0_START;
227 		buf = urb->setup_packet;
228 		len = 8;
229 		break;
230 	case USB_ENDPOINT_XFER_ISOC:
231 		qh->iso_idx = 0;
232 		qh->frame = 0;
233 		offset = urb->iso_frame_desc[0].offset;
234 		len = urb->iso_frame_desc[0].length;
235 		break;
236 	default:		/* bulk, interrupt */
237 		/* actual_length may be nonzero on retry paths */
238 		buf = urb->transfer_buffer + urb->actual_length;
239 		len = urb->transfer_buffer_length - urb->actual_length;
240 	}
241 
242 	DBG(4, "qh %p urb %p dev%d ep%d%s%s, hw_ep %d, %p/%d\n",
243 			qh, urb, address, qh->epnum,
244 			is_in ? "in" : "out",
245 			({char *s; switch (qh->type) {
246 			case USB_ENDPOINT_XFER_CONTROL:	s = ""; break;
247 			case USB_ENDPOINT_XFER_BULK:	s = "-bulk"; break;
248 			case USB_ENDPOINT_XFER_ISOC:	s = "-iso"; break;
249 			default:			s = "-intr"; break;
250 			}; s; }),
251 			epnum, buf + offset, len);
252 
253 	/* Configure endpoint */
254 	musb_ep_set_qh(hw_ep, is_in, qh);
255 	musb_ep_program(musb, epnum, urb, !is_in, buf, offset, len);
256 
257 	/* transmit may have more work: start it when it is time */
258 	if (is_in)
259 		return;
260 
261 	/* determine if the time is right for a periodic transfer */
262 	switch (qh->type) {
263 	case USB_ENDPOINT_XFER_ISOC:
264 	case USB_ENDPOINT_XFER_INT:
265 		DBG(3, "check whether there's still time for periodic Tx\n");
266 		frame = musb_readw(mbase, MUSB_FRAME);
267 		/* FIXME this doesn't implement that scheduling policy ...
268 		 * or handle framecounter wrapping
269 		 */
270 		if ((urb->transfer_flags & URB_ISO_ASAP)
271 				|| (frame >= urb->start_frame)) {
272 			/* REVISIT the SOF irq handler shouldn't duplicate
273 			 * this code; and we don't init urb->start_frame...
274 			 */
275 			qh->frame = 0;
276 			goto start;
277 		} else {
278 			qh->frame = urb->start_frame;
279 			/* enable SOF interrupt so we can count down */
280 			DBG(1, "SOF for %d\n", epnum);
281 #if 1 /* ifndef	CONFIG_ARCH_DAVINCI */
282 			musb_writeb(mbase, MUSB_INTRUSBE, 0xff);
283 #endif
284 		}
285 		break;
286 	default:
287 start:
288 		DBG(4, "Start TX%d %s\n", epnum,
289 			hw_ep->tx_channel ? "dma" : "pio");
290 
291 		if (!hw_ep->tx_channel)
292 			musb_h_tx_start(hw_ep);
293 		else if (is_cppi_enabled() || tusb_dma_omap())
294 			musb_h_tx_dma_start(hw_ep);
295 	}
296 }
297 
298 /* Context: caller owns controller lock, IRQs are blocked */
299 static void musb_giveback(struct musb *musb, struct urb *urb, int status)
300 __releases(musb->lock)
301 __acquires(musb->lock)
302 {
303 	DBG(({ int level; switch (status) {
304 				case 0:
305 					level = 4;
306 					break;
307 				/* common/boring faults */
308 				case -EREMOTEIO:
309 				case -ESHUTDOWN:
310 				case -ECONNRESET:
311 				case -EPIPE:
312 					level = 3;
313 					break;
314 				default:
315 					level = 2;
316 					break;
317 				}; level; }),
318 			"complete %p %pF (%d), dev%d ep%d%s, %d/%d\n",
319 			urb, urb->complete, status,
320 			usb_pipedevice(urb->pipe),
321 			usb_pipeendpoint(urb->pipe),
322 			usb_pipein(urb->pipe) ? "in" : "out",
323 			urb->actual_length, urb->transfer_buffer_length
324 			);
325 
326 	usb_hcd_unlink_urb_from_ep(musb_to_hcd(musb), urb);
327 	spin_unlock(&musb->lock);
328 	usb_hcd_giveback_urb(musb_to_hcd(musb), urb, status);
329 	spin_lock(&musb->lock);
330 }
331 
332 /* For bulk/interrupt endpoints only */
333 static inline void musb_save_toggle(struct musb_qh *qh, int is_in,
334 				    struct urb *urb)
335 {
336 	void __iomem		*epio = qh->hw_ep->regs;
337 	u16			csr;
338 
339 	/*
340 	 * FIXME: the current Mentor DMA code seems to have
341 	 * problems getting toggle correct.
342 	 */
343 
344 	if (is_in)
345 		csr = musb_readw(epio, MUSB_RXCSR) & MUSB_RXCSR_H_DATATOGGLE;
346 	else
347 		csr = musb_readw(epio, MUSB_TXCSR) & MUSB_TXCSR_H_DATATOGGLE;
348 
349 	usb_settoggle(urb->dev, qh->epnum, !is_in, csr ? 1 : 0);
350 }
351 
352 /*
353  * Advance this hardware endpoint's queue, completing the specified URB and
354  * advancing to either the next URB queued to that qh, or else invalidating
355  * that qh and advancing to the next qh scheduled after the current one.
356  *
357  * Context: caller owns controller lock, IRQs are blocked
358  */
359 static void musb_advance_schedule(struct musb *musb, struct urb *urb,
360 				  struct musb_hw_ep *hw_ep, int is_in)
361 {
362 	struct musb_qh		*qh = musb_ep_get_qh(hw_ep, is_in);
363 	struct musb_hw_ep	*ep = qh->hw_ep;
364 	int			ready = qh->is_ready;
365 	int			status;
366 
367 	status = (urb->status == -EINPROGRESS) ? 0 : urb->status;
368 
369 	/* save toggle eagerly, for paranoia */
370 	switch (qh->type) {
371 	case USB_ENDPOINT_XFER_BULK:
372 	case USB_ENDPOINT_XFER_INT:
373 		musb_save_toggle(qh, is_in, urb);
374 		break;
375 	case USB_ENDPOINT_XFER_ISOC:
376 		if (status == 0 && urb->error_count)
377 			status = -EXDEV;
378 		break;
379 	}
380 
381 	qh->is_ready = 0;
382 	musb_giveback(musb, urb, status);
383 	qh->is_ready = ready;
384 
385 	/* reclaim resources (and bandwidth) ASAP; deschedule it, and
386 	 * invalidate qh as soon as list_empty(&hep->urb_list)
387 	 */
388 	if (list_empty(&qh->hep->urb_list)) {
389 		struct list_head	*head;
390 
391 		if (is_in)
392 			ep->rx_reinit = 1;
393 		else
394 			ep->tx_reinit = 1;
395 
396 		/* Clobber old pointers to this qh */
397 		musb_ep_set_qh(ep, is_in, NULL);
398 		qh->hep->hcpriv = NULL;
399 
400 		switch (qh->type) {
401 
402 		case USB_ENDPOINT_XFER_CONTROL:
403 		case USB_ENDPOINT_XFER_BULK:
404 			/* fifo policy for these lists, except that NAKing
405 			 * should rotate a qh to the end (for fairness).
406 			 */
407 			if (qh->mux == 1) {
408 				head = qh->ring.prev;
409 				list_del(&qh->ring);
410 				kfree(qh);
411 				qh = first_qh(head);
412 				break;
413 			}
414 
415 		case USB_ENDPOINT_XFER_ISOC:
416 		case USB_ENDPOINT_XFER_INT:
417 			/* this is where periodic bandwidth should be
418 			 * de-allocated if it's tracked and allocated;
419 			 * and where we'd update the schedule tree...
420 			 */
421 			kfree(qh);
422 			qh = NULL;
423 			break;
424 		}
425 	}
426 
427 	if (qh != NULL && qh->is_ready) {
428 		DBG(4, "... next ep%d %cX urb %p\n",
429 		    hw_ep->epnum, is_in ? 'R' : 'T', next_urb(qh));
430 		musb_start_urb(musb, is_in, qh);
431 	}
432 }
433 
434 static u16 musb_h_flush_rxfifo(struct musb_hw_ep *hw_ep, u16 csr)
435 {
436 	/* we don't want fifo to fill itself again;
437 	 * ignore dma (various models),
438 	 * leave toggle alone (may not have been saved yet)
439 	 */
440 	csr |= MUSB_RXCSR_FLUSHFIFO | MUSB_RXCSR_RXPKTRDY;
441 	csr &= ~(MUSB_RXCSR_H_REQPKT
442 		| MUSB_RXCSR_H_AUTOREQ
443 		| MUSB_RXCSR_AUTOCLEAR);
444 
445 	/* write 2x to allow double buffering */
446 	musb_writew(hw_ep->regs, MUSB_RXCSR, csr);
447 	musb_writew(hw_ep->regs, MUSB_RXCSR, csr);
448 
449 	/* flush writebuffer */
450 	return musb_readw(hw_ep->regs, MUSB_RXCSR);
451 }
452 
453 /*
454  * PIO RX for a packet (or part of it).
455  */
456 static bool
457 musb_host_packet_rx(struct musb *musb, struct urb *urb, u8 epnum, u8 iso_err)
458 {
459 	u16			rx_count;
460 	u8			*buf;
461 	u16			csr;
462 	bool			done = false;
463 	u32			length;
464 	int			do_flush = 0;
465 	struct musb_hw_ep	*hw_ep = musb->endpoints + epnum;
466 	void __iomem		*epio = hw_ep->regs;
467 	struct musb_qh		*qh = hw_ep->in_qh;
468 	int			pipe = urb->pipe;
469 	void			*buffer = urb->transfer_buffer;
470 
471 	/* musb_ep_select(mbase, epnum); */
472 	rx_count = musb_readw(epio, MUSB_RXCOUNT);
473 	DBG(3, "RX%d count %d, buffer %p len %d/%d\n", epnum, rx_count,
474 			urb->transfer_buffer, qh->offset,
475 			urb->transfer_buffer_length);
476 
477 	/* unload FIFO */
478 	if (usb_pipeisoc(pipe)) {
479 		int					status = 0;
480 		struct usb_iso_packet_descriptor	*d;
481 
482 		if (iso_err) {
483 			status = -EILSEQ;
484 			urb->error_count++;
485 		}
486 
487 		d = urb->iso_frame_desc + qh->iso_idx;
488 		buf = buffer + d->offset;
489 		length = d->length;
490 		if (rx_count > length) {
491 			if (status == 0) {
492 				status = -EOVERFLOW;
493 				urb->error_count++;
494 			}
495 			DBG(2, "** OVERFLOW %d into %d\n", rx_count, length);
496 			do_flush = 1;
497 		} else
498 			length = rx_count;
499 		urb->actual_length += length;
500 		d->actual_length = length;
501 
502 		d->status = status;
503 
504 		/* see if we are done */
505 		done = (++qh->iso_idx >= urb->number_of_packets);
506 	} else {
507 		/* non-isoch */
508 		buf = buffer + qh->offset;
509 		length = urb->transfer_buffer_length - qh->offset;
510 		if (rx_count > length) {
511 			if (urb->status == -EINPROGRESS)
512 				urb->status = -EOVERFLOW;
513 			DBG(2, "** OVERFLOW %d into %d\n", rx_count, length);
514 			do_flush = 1;
515 		} else
516 			length = rx_count;
517 		urb->actual_length += length;
518 		qh->offset += length;
519 
520 		/* see if we are done */
521 		done = (urb->actual_length == urb->transfer_buffer_length)
522 			|| (rx_count < qh->maxpacket)
523 			|| (urb->status != -EINPROGRESS);
524 		if (done
525 				&& (urb->status == -EINPROGRESS)
526 				&& (urb->transfer_flags & URB_SHORT_NOT_OK)
527 				&& (urb->actual_length
528 					< urb->transfer_buffer_length))
529 			urb->status = -EREMOTEIO;
530 	}
531 
532 	musb_read_fifo(hw_ep, length, buf);
533 
534 	csr = musb_readw(epio, MUSB_RXCSR);
535 	csr |= MUSB_RXCSR_H_WZC_BITS;
536 	if (unlikely(do_flush))
537 		musb_h_flush_rxfifo(hw_ep, csr);
538 	else {
539 		/* REVISIT this assumes AUTOCLEAR is never set */
540 		csr &= ~(MUSB_RXCSR_RXPKTRDY | MUSB_RXCSR_H_REQPKT);
541 		if (!done)
542 			csr |= MUSB_RXCSR_H_REQPKT;
543 		musb_writew(epio, MUSB_RXCSR, csr);
544 	}
545 
546 	return done;
547 }
548 
549 /* we don't always need to reinit a given side of an endpoint...
550  * when we do, use tx/rx reinit routine and then construct a new CSR
551  * to address data toggle, NYET, and DMA or PIO.
552  *
553  * it's possible that driver bugs (especially for DMA) or aborting a
554  * transfer might have left the endpoint busier than it should be.
555  * the busy/not-empty tests are basically paranoia.
556  */
557 static void
558 musb_rx_reinit(struct musb *musb, struct musb_qh *qh, struct musb_hw_ep *ep)
559 {
560 	u16	csr;
561 
562 	/* NOTE:  we know the "rx" fifo reinit never triggers for ep0.
563 	 * That always uses tx_reinit since ep0 repurposes TX register
564 	 * offsets; the initial SETUP packet is also a kind of OUT.
565 	 */
566 
567 	/* if programmed for Tx, put it in RX mode */
568 	if (ep->is_shared_fifo) {
569 		csr = musb_readw(ep->regs, MUSB_TXCSR);
570 		if (csr & MUSB_TXCSR_MODE) {
571 			musb_h_tx_flush_fifo(ep);
572 			csr = musb_readw(ep->regs, MUSB_TXCSR);
573 			musb_writew(ep->regs, MUSB_TXCSR,
574 				    csr | MUSB_TXCSR_FRCDATATOG);
575 		}
576 
577 		/*
578 		 * Clear the MODE bit (and everything else) to enable Rx.
579 		 * NOTE: we mustn't clear the DMAMODE bit before DMAENAB.
580 		 */
581 		if (csr & MUSB_TXCSR_DMAMODE)
582 			musb_writew(ep->regs, MUSB_TXCSR, MUSB_TXCSR_DMAMODE);
583 		musb_writew(ep->regs, MUSB_TXCSR, 0);
584 
585 	/* scrub all previous state, clearing toggle */
586 	} else {
587 		csr = musb_readw(ep->regs, MUSB_RXCSR);
588 		if (csr & MUSB_RXCSR_RXPKTRDY)
589 			WARNING("rx%d, packet/%d ready?\n", ep->epnum,
590 				musb_readw(ep->regs, MUSB_RXCOUNT));
591 
592 		musb_h_flush_rxfifo(ep, MUSB_RXCSR_CLRDATATOG);
593 	}
594 
595 	/* target addr and (for multipoint) hub addr/port */
596 	if (musb->is_multipoint) {
597 		musb_write_rxfunaddr(ep->target_regs, qh->addr_reg);
598 		musb_write_rxhubaddr(ep->target_regs, qh->h_addr_reg);
599 		musb_write_rxhubport(ep->target_regs, qh->h_port_reg);
600 
601 	} else
602 		musb_writeb(musb->mregs, MUSB_FADDR, qh->addr_reg);
603 
604 	/* protocol/endpoint, interval/NAKlimit, i/o size */
605 	musb_writeb(ep->regs, MUSB_RXTYPE, qh->type_reg);
606 	musb_writeb(ep->regs, MUSB_RXINTERVAL, qh->intv_reg);
607 	/* NOTE: bulk combining rewrites high bits of maxpacket */
608 	/* Set RXMAXP with the FIFO size of the endpoint
609 	 * to disable double buffer mode.
610 	 */
611 	if (musb->hwvers < MUSB_HWVERS_2000)
612 		musb_writew(ep->regs, MUSB_RXMAXP, ep->max_packet_sz_rx);
613 	else
614 		musb_writew(ep->regs, MUSB_RXMAXP,
615 				qh->maxpacket | ((qh->hb_mult - 1) << 11));
616 
617 	ep->rx_reinit = 0;
618 }
619 
620 static bool musb_tx_dma_program(struct dma_controller *dma,
621 		struct musb_hw_ep *hw_ep, struct musb_qh *qh,
622 		struct urb *urb, u32 offset, u32 length)
623 {
624 	struct dma_channel	*channel = hw_ep->tx_channel;
625 	void __iomem		*epio = hw_ep->regs;
626 	u16			pkt_size = qh->maxpacket;
627 	u16			csr;
628 	u8			mode;
629 
630 #ifdef	CONFIG_USB_INVENTRA_DMA
631 	if (length > channel->max_len)
632 		length = channel->max_len;
633 
634 	csr = musb_readw(epio, MUSB_TXCSR);
635 	if (length > pkt_size) {
636 		mode = 1;
637 		csr |= MUSB_TXCSR_DMAMODE | MUSB_TXCSR_DMAENAB;
638 		/* autoset shouldn't be set in high bandwidth */
639 		if (qh->hb_mult == 1)
640 			csr |= MUSB_TXCSR_AUTOSET;
641 	} else {
642 		mode = 0;
643 		csr &= ~(MUSB_TXCSR_AUTOSET | MUSB_TXCSR_DMAMODE);
644 		csr |= MUSB_TXCSR_DMAENAB; /* against programmer's guide */
645 	}
646 	channel->desired_mode = mode;
647 	musb_writew(epio, MUSB_TXCSR, csr);
648 #else
649 	if (!is_cppi_enabled() && !tusb_dma_omap())
650 		return false;
651 
652 	channel->actual_len = 0;
653 
654 	/*
655 	 * TX uses "RNDIS" mode automatically but needs help
656 	 * to identify the zero-length-final-packet case.
657 	 */
658 	mode = (urb->transfer_flags & URB_ZERO_PACKET) ? 1 : 0;
659 #endif
660 
661 	qh->segsize = length;
662 
663 	if (!dma->channel_program(channel, pkt_size, mode,
664 			urb->transfer_dma + offset, length)) {
665 		dma->channel_release(channel);
666 		hw_ep->tx_channel = NULL;
667 
668 		csr = musb_readw(epio, MUSB_TXCSR);
669 		csr &= ~(MUSB_TXCSR_AUTOSET | MUSB_TXCSR_DMAENAB);
670 		musb_writew(epio, MUSB_TXCSR, csr | MUSB_TXCSR_H_WZC_BITS);
671 		return false;
672 	}
673 	return true;
674 }
675 
676 /*
677  * Program an HDRC endpoint as per the given URB
678  * Context: irqs blocked, controller lock held
679  */
680 static void musb_ep_program(struct musb *musb, u8 epnum,
681 			struct urb *urb, int is_out,
682 			u8 *buf, u32 offset, u32 len)
683 {
684 	struct dma_controller	*dma_controller;
685 	struct dma_channel	*dma_channel;
686 	u8			dma_ok;
687 	void __iomem		*mbase = musb->mregs;
688 	struct musb_hw_ep	*hw_ep = musb->endpoints + epnum;
689 	void __iomem		*epio = hw_ep->regs;
690 	struct musb_qh		*qh = musb_ep_get_qh(hw_ep, !is_out);
691 	u16			packet_sz = qh->maxpacket;
692 
693 	DBG(3, "%s hw%d urb %p spd%d dev%d ep%d%s "
694 				"h_addr%02x h_port%02x bytes %d\n",
695 			is_out ? "-->" : "<--",
696 			epnum, urb, urb->dev->speed,
697 			qh->addr_reg, qh->epnum, is_out ? "out" : "in",
698 			qh->h_addr_reg, qh->h_port_reg,
699 			len);
700 
701 	musb_ep_select(mbase, epnum);
702 
703 	/* candidate for DMA? */
704 	dma_controller = musb->dma_controller;
705 	if (is_dma_capable() && epnum && dma_controller) {
706 		dma_channel = is_out ? hw_ep->tx_channel : hw_ep->rx_channel;
707 		if (!dma_channel) {
708 			dma_channel = dma_controller->channel_alloc(
709 					dma_controller, hw_ep, is_out);
710 			if (is_out)
711 				hw_ep->tx_channel = dma_channel;
712 			else
713 				hw_ep->rx_channel = dma_channel;
714 		}
715 	} else
716 		dma_channel = NULL;
717 
718 	/* make sure we clear DMAEnab, autoSet bits from previous run */
719 
720 	/* OUT/transmit/EP0 or IN/receive? */
721 	if (is_out) {
722 		u16	csr;
723 		u16	int_txe;
724 		u16	load_count;
725 
726 		csr = musb_readw(epio, MUSB_TXCSR);
727 
728 		/* disable interrupt in case we flush */
729 		int_txe = musb_readw(mbase, MUSB_INTRTXE);
730 		musb_writew(mbase, MUSB_INTRTXE, int_txe & ~(1 << epnum));
731 
732 		/* general endpoint setup */
733 		if (epnum) {
734 			/* flush all old state, set default */
735 			musb_h_tx_flush_fifo(hw_ep);
736 
737 			/*
738 			 * We must not clear the DMAMODE bit before or in
739 			 * the same cycle with the DMAENAB bit, so we clear
740 			 * the latter first...
741 			 */
742 			csr &= ~(MUSB_TXCSR_H_NAKTIMEOUT
743 					| MUSB_TXCSR_AUTOSET
744 					| MUSB_TXCSR_DMAENAB
745 					| MUSB_TXCSR_FRCDATATOG
746 					| MUSB_TXCSR_H_RXSTALL
747 					| MUSB_TXCSR_H_ERROR
748 					| MUSB_TXCSR_TXPKTRDY
749 					);
750 			csr |= MUSB_TXCSR_MODE;
751 
752 			if (usb_gettoggle(urb->dev, qh->epnum, 1))
753 				csr |= MUSB_TXCSR_H_WR_DATATOGGLE
754 					| MUSB_TXCSR_H_DATATOGGLE;
755 			else
756 				csr |= MUSB_TXCSR_CLRDATATOG;
757 
758 			musb_writew(epio, MUSB_TXCSR, csr);
759 			/* REVISIT may need to clear FLUSHFIFO ... */
760 			csr &= ~MUSB_TXCSR_DMAMODE;
761 			musb_writew(epio, MUSB_TXCSR, csr);
762 			csr = musb_readw(epio, MUSB_TXCSR);
763 		} else {
764 			/* endpoint 0: just flush */
765 			musb_h_ep0_flush_fifo(hw_ep);
766 		}
767 
768 		/* target addr and (for multipoint) hub addr/port */
769 		if (musb->is_multipoint) {
770 			musb_write_txfunaddr(mbase, epnum, qh->addr_reg);
771 			musb_write_txhubaddr(mbase, epnum, qh->h_addr_reg);
772 			musb_write_txhubport(mbase, epnum, qh->h_port_reg);
773 /* FIXME if !epnum, do the same for RX ... */
774 		} else
775 			musb_writeb(mbase, MUSB_FADDR, qh->addr_reg);
776 
777 		/* protocol/endpoint/interval/NAKlimit */
778 		if (epnum) {
779 			musb_writeb(epio, MUSB_TXTYPE, qh->type_reg);
780 			if (can_bulk_split(musb, qh->type))
781 				musb_writew(epio, MUSB_TXMAXP,
782 					packet_sz
783 					| ((hw_ep->max_packet_sz_tx /
784 						packet_sz) - 1) << 11);
785 			else
786 				musb_writew(epio, MUSB_TXMAXP,
787 					packet_sz);
788 			musb_writeb(epio, MUSB_TXINTERVAL, qh->intv_reg);
789 		} else {
790 			musb_writeb(epio, MUSB_NAKLIMIT0, qh->intv_reg);
791 			if (musb->is_multipoint)
792 				musb_writeb(epio, MUSB_TYPE0,
793 						qh->type_reg);
794 		}
795 
796 		if (can_bulk_split(musb, qh->type))
797 			load_count = min((u32) hw_ep->max_packet_sz_tx,
798 						len);
799 		else
800 			load_count = min((u32) packet_sz, len);
801 
802 		if (dma_channel && musb_tx_dma_program(dma_controller,
803 					hw_ep, qh, urb, offset, len))
804 			load_count = 0;
805 
806 		if (load_count) {
807 			/* PIO to load FIFO */
808 			qh->segsize = load_count;
809 			musb_write_fifo(hw_ep, load_count, buf);
810 		}
811 
812 		/* re-enable interrupt */
813 		musb_writew(mbase, MUSB_INTRTXE, int_txe);
814 
815 	/* IN/receive */
816 	} else {
817 		u16	csr;
818 
819 		if (hw_ep->rx_reinit) {
820 			musb_rx_reinit(musb, qh, hw_ep);
821 
822 			/* init new state: toggle and NYET, maybe DMA later */
823 			if (usb_gettoggle(urb->dev, qh->epnum, 0))
824 				csr = MUSB_RXCSR_H_WR_DATATOGGLE
825 					| MUSB_RXCSR_H_DATATOGGLE;
826 			else
827 				csr = 0;
828 			if (qh->type == USB_ENDPOINT_XFER_INT)
829 				csr |= MUSB_RXCSR_DISNYET;
830 
831 		} else {
832 			csr = musb_readw(hw_ep->regs, MUSB_RXCSR);
833 
834 			if (csr & (MUSB_RXCSR_RXPKTRDY
835 					| MUSB_RXCSR_DMAENAB
836 					| MUSB_RXCSR_H_REQPKT))
837 				ERR("broken !rx_reinit, ep%d csr %04x\n",
838 						hw_ep->epnum, csr);
839 
840 			/* scrub any stale state, leaving toggle alone */
841 			csr &= MUSB_RXCSR_DISNYET;
842 		}
843 
844 		/* kick things off */
845 
846 		if ((is_cppi_enabled() || tusb_dma_omap()) && dma_channel) {
847 			/* candidate for DMA */
848 			if (dma_channel) {
849 				dma_channel->actual_len = 0L;
850 				qh->segsize = len;
851 
852 				/* AUTOREQ is in a DMA register */
853 				musb_writew(hw_ep->regs, MUSB_RXCSR, csr);
854 				csr = musb_readw(hw_ep->regs,
855 						MUSB_RXCSR);
856 
857 				/* unless caller treats short rx transfers as
858 				 * errors, we dare not queue multiple transfers.
859 				 */
860 				dma_ok = dma_controller->channel_program(
861 						dma_channel, packet_sz,
862 						!(urb->transfer_flags
863 							& URB_SHORT_NOT_OK),
864 						urb->transfer_dma + offset,
865 						qh->segsize);
866 				if (!dma_ok) {
867 					dma_controller->channel_release(
868 							dma_channel);
869 					hw_ep->rx_channel = NULL;
870 					dma_channel = NULL;
871 				} else
872 					csr |= MUSB_RXCSR_DMAENAB;
873 			}
874 		}
875 
876 		csr |= MUSB_RXCSR_H_REQPKT;
877 		DBG(7, "RXCSR%d := %04x\n", epnum, csr);
878 		musb_writew(hw_ep->regs, MUSB_RXCSR, csr);
879 		csr = musb_readw(hw_ep->regs, MUSB_RXCSR);
880 	}
881 }
882 
883 
884 /*
885  * Service the default endpoint (ep0) as host.
886  * Return true until it's time to start the status stage.
887  */
888 static bool musb_h_ep0_continue(struct musb *musb, u16 len, struct urb *urb)
889 {
890 	bool			 more = false;
891 	u8			*fifo_dest = NULL;
892 	u16			fifo_count = 0;
893 	struct musb_hw_ep	*hw_ep = musb->control_ep;
894 	struct musb_qh		*qh = hw_ep->in_qh;
895 	struct usb_ctrlrequest	*request;
896 
897 	switch (musb->ep0_stage) {
898 	case MUSB_EP0_IN:
899 		fifo_dest = urb->transfer_buffer + urb->actual_length;
900 		fifo_count = min_t(size_t, len, urb->transfer_buffer_length -
901 				   urb->actual_length);
902 		if (fifo_count < len)
903 			urb->status = -EOVERFLOW;
904 
905 		musb_read_fifo(hw_ep, fifo_count, fifo_dest);
906 
907 		urb->actual_length += fifo_count;
908 		if (len < qh->maxpacket) {
909 			/* always terminate on short read; it's
910 			 * rarely reported as an error.
911 			 */
912 		} else if (urb->actual_length <
913 				urb->transfer_buffer_length)
914 			more = true;
915 		break;
916 	case MUSB_EP0_START:
917 		request = (struct usb_ctrlrequest *) urb->setup_packet;
918 
919 		if (!request->wLength) {
920 			DBG(4, "start no-DATA\n");
921 			break;
922 		} else if (request->bRequestType & USB_DIR_IN) {
923 			DBG(4, "start IN-DATA\n");
924 			musb->ep0_stage = MUSB_EP0_IN;
925 			more = true;
926 			break;
927 		} else {
928 			DBG(4, "start OUT-DATA\n");
929 			musb->ep0_stage = MUSB_EP0_OUT;
930 			more = true;
931 		}
932 		/* FALLTHROUGH */
933 	case MUSB_EP0_OUT:
934 		fifo_count = min_t(size_t, qh->maxpacket,
935 				   urb->transfer_buffer_length -
936 				   urb->actual_length);
937 		if (fifo_count) {
938 			fifo_dest = (u8 *) (urb->transfer_buffer
939 					+ urb->actual_length);
940 			DBG(3, "Sending %d byte%s to ep0 fifo %p\n",
941 					fifo_count,
942 					(fifo_count == 1) ? "" : "s",
943 					fifo_dest);
944 			musb_write_fifo(hw_ep, fifo_count, fifo_dest);
945 
946 			urb->actual_length += fifo_count;
947 			more = true;
948 		}
949 		break;
950 	default:
951 		ERR("bogus ep0 stage %d\n", musb->ep0_stage);
952 		break;
953 	}
954 
955 	return more;
956 }
957 
958 /*
959  * Handle default endpoint interrupt as host. Only called in IRQ time
960  * from musb_interrupt().
961  *
962  * called with controller irqlocked
963  */
964 irqreturn_t musb_h_ep0_irq(struct musb *musb)
965 {
966 	struct urb		*urb;
967 	u16			csr, len;
968 	int			status = 0;
969 	void __iomem		*mbase = musb->mregs;
970 	struct musb_hw_ep	*hw_ep = musb->control_ep;
971 	void __iomem		*epio = hw_ep->regs;
972 	struct musb_qh		*qh = hw_ep->in_qh;
973 	bool			complete = false;
974 	irqreturn_t		retval = IRQ_NONE;
975 
976 	/* ep0 only has one queue, "in" */
977 	urb = next_urb(qh);
978 
979 	musb_ep_select(mbase, 0);
980 	csr = musb_readw(epio, MUSB_CSR0);
981 	len = (csr & MUSB_CSR0_RXPKTRDY)
982 			? musb_readb(epio, MUSB_COUNT0)
983 			: 0;
984 
985 	DBG(4, "<== csr0 %04x, qh %p, count %d, urb %p, stage %d\n",
986 		csr, qh, len, urb, musb->ep0_stage);
987 
988 	/* if we just did status stage, we are done */
989 	if (MUSB_EP0_STATUS == musb->ep0_stage) {
990 		retval = IRQ_HANDLED;
991 		complete = true;
992 	}
993 
994 	/* prepare status */
995 	if (csr & MUSB_CSR0_H_RXSTALL) {
996 		DBG(6, "STALLING ENDPOINT\n");
997 		status = -EPIPE;
998 
999 	} else if (csr & MUSB_CSR0_H_ERROR) {
1000 		DBG(2, "no response, csr0 %04x\n", csr);
1001 		status = -EPROTO;
1002 
1003 	} else if (csr & MUSB_CSR0_H_NAKTIMEOUT) {
1004 		DBG(2, "control NAK timeout\n");
1005 
1006 		/* NOTE:  this code path would be a good place to PAUSE a
1007 		 * control transfer, if another one is queued, so that
1008 		 * ep0 is more likely to stay busy.  That's already done
1009 		 * for bulk RX transfers.
1010 		 *
1011 		 * if (qh->ring.next != &musb->control), then
1012 		 * we have a candidate... NAKing is *NOT* an error
1013 		 */
1014 		musb_writew(epio, MUSB_CSR0, 0);
1015 		retval = IRQ_HANDLED;
1016 	}
1017 
1018 	if (status) {
1019 		DBG(6, "aborting\n");
1020 		retval = IRQ_HANDLED;
1021 		if (urb)
1022 			urb->status = status;
1023 		complete = true;
1024 
1025 		/* use the proper sequence to abort the transfer */
1026 		if (csr & MUSB_CSR0_H_REQPKT) {
1027 			csr &= ~MUSB_CSR0_H_REQPKT;
1028 			musb_writew(epio, MUSB_CSR0, csr);
1029 			csr &= ~MUSB_CSR0_H_NAKTIMEOUT;
1030 			musb_writew(epio, MUSB_CSR0, csr);
1031 		} else {
1032 			musb_h_ep0_flush_fifo(hw_ep);
1033 		}
1034 
1035 		musb_writeb(epio, MUSB_NAKLIMIT0, 0);
1036 
1037 		/* clear it */
1038 		musb_writew(epio, MUSB_CSR0, 0);
1039 	}
1040 
1041 	if (unlikely(!urb)) {
1042 		/* stop endpoint since we have no place for its data, this
1043 		 * SHOULD NEVER HAPPEN! */
1044 		ERR("no URB for end 0\n");
1045 
1046 		musb_h_ep0_flush_fifo(hw_ep);
1047 		goto done;
1048 	}
1049 
1050 	if (!complete) {
1051 		/* call common logic and prepare response */
1052 		if (musb_h_ep0_continue(musb, len, urb)) {
1053 			/* more packets required */
1054 			csr = (MUSB_EP0_IN == musb->ep0_stage)
1055 				?  MUSB_CSR0_H_REQPKT : MUSB_CSR0_TXPKTRDY;
1056 		} else {
1057 			/* data transfer complete; perform status phase */
1058 			if (usb_pipeout(urb->pipe)
1059 					|| !urb->transfer_buffer_length)
1060 				csr = MUSB_CSR0_H_STATUSPKT
1061 					| MUSB_CSR0_H_REQPKT;
1062 			else
1063 				csr = MUSB_CSR0_H_STATUSPKT
1064 					| MUSB_CSR0_TXPKTRDY;
1065 
1066 			/* flag status stage */
1067 			musb->ep0_stage = MUSB_EP0_STATUS;
1068 
1069 			DBG(5, "ep0 STATUS, csr %04x\n", csr);
1070 
1071 		}
1072 		musb_writew(epio, MUSB_CSR0, csr);
1073 		retval = IRQ_HANDLED;
1074 	} else
1075 		musb->ep0_stage = MUSB_EP0_IDLE;
1076 
1077 	/* call completion handler if done */
1078 	if (complete)
1079 		musb_advance_schedule(musb, urb, hw_ep, 1);
1080 done:
1081 	return retval;
1082 }
1083 
1084 
1085 #ifdef CONFIG_USB_INVENTRA_DMA
1086 
1087 /* Host side TX (OUT) using Mentor DMA works as follows:
1088 	submit_urb ->
1089 		- if queue was empty, Program Endpoint
1090 		- ... which starts DMA to fifo in mode 1 or 0
1091 
1092 	DMA Isr (transfer complete) -> TxAvail()
1093 		- Stop DMA (~DmaEnab)	(<--- Alert ... currently happens
1094 					only in musb_cleanup_urb)
1095 		- TxPktRdy has to be set in mode 0 or for
1096 			short packets in mode 1.
1097 */
1098 
1099 #endif
1100 
1101 /* Service a Tx-Available or dma completion irq for the endpoint */
1102 void musb_host_tx(struct musb *musb, u8 epnum)
1103 {
1104 	int			pipe;
1105 	bool			done = false;
1106 	u16			tx_csr;
1107 	size_t			length = 0;
1108 	size_t			offset = 0;
1109 	struct musb_hw_ep	*hw_ep = musb->endpoints + epnum;
1110 	void __iomem		*epio = hw_ep->regs;
1111 	struct musb_qh		*qh = hw_ep->out_qh;
1112 	struct urb		*urb = next_urb(qh);
1113 	u32			status = 0;
1114 	void __iomem		*mbase = musb->mregs;
1115 	struct dma_channel	*dma;
1116 
1117 	musb_ep_select(mbase, epnum);
1118 	tx_csr = musb_readw(epio, MUSB_TXCSR);
1119 
1120 	/* with CPPI, DMA sometimes triggers "extra" irqs */
1121 	if (!urb) {
1122 		DBG(4, "extra TX%d ready, csr %04x\n", epnum, tx_csr);
1123 		return;
1124 	}
1125 
1126 	pipe = urb->pipe;
1127 	dma = is_dma_capable() ? hw_ep->tx_channel : NULL;
1128 	DBG(4, "OUT/TX%d end, csr %04x%s\n", epnum, tx_csr,
1129 			dma ? ", dma" : "");
1130 
1131 	/* check for errors */
1132 	if (tx_csr & MUSB_TXCSR_H_RXSTALL) {
1133 		/* dma was disabled, fifo flushed */
1134 		DBG(3, "TX end %d stall\n", epnum);
1135 
1136 		/* stall; record URB status */
1137 		status = -EPIPE;
1138 
1139 	} else if (tx_csr & MUSB_TXCSR_H_ERROR) {
1140 		/* (NON-ISO) dma was disabled, fifo flushed */
1141 		DBG(3, "TX 3strikes on ep=%d\n", epnum);
1142 
1143 		status = -ETIMEDOUT;
1144 
1145 	} else if (tx_csr & MUSB_TXCSR_H_NAKTIMEOUT) {
1146 		DBG(6, "TX end=%d device not responding\n", epnum);
1147 
1148 		/* NOTE:  this code path would be a good place to PAUSE a
1149 		 * transfer, if there's some other (nonperiodic) tx urb
1150 		 * that could use this fifo.  (dma complicates it...)
1151 		 * That's already done for bulk RX transfers.
1152 		 *
1153 		 * if (bulk && qh->ring.next != &musb->out_bulk), then
1154 		 * we have a candidate... NAKing is *NOT* an error
1155 		 */
1156 		musb_ep_select(mbase, epnum);
1157 		musb_writew(epio, MUSB_TXCSR,
1158 				MUSB_TXCSR_H_WZC_BITS
1159 				| MUSB_TXCSR_TXPKTRDY);
1160 		return;
1161 	}
1162 
1163 	if (status) {
1164 		if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1165 			dma->status = MUSB_DMA_STATUS_CORE_ABORT;
1166 			(void) musb->dma_controller->channel_abort(dma);
1167 		}
1168 
1169 		/* do the proper sequence to abort the transfer in the
1170 		 * usb core; the dma engine should already be stopped.
1171 		 */
1172 		musb_h_tx_flush_fifo(hw_ep);
1173 		tx_csr &= ~(MUSB_TXCSR_AUTOSET
1174 				| MUSB_TXCSR_DMAENAB
1175 				| MUSB_TXCSR_H_ERROR
1176 				| MUSB_TXCSR_H_RXSTALL
1177 				| MUSB_TXCSR_H_NAKTIMEOUT
1178 				);
1179 
1180 		musb_ep_select(mbase, epnum);
1181 		musb_writew(epio, MUSB_TXCSR, tx_csr);
1182 		/* REVISIT may need to clear FLUSHFIFO ... */
1183 		musb_writew(epio, MUSB_TXCSR, tx_csr);
1184 		musb_writeb(epio, MUSB_TXINTERVAL, 0);
1185 
1186 		done = true;
1187 	}
1188 
1189 	/* second cppi case */
1190 	if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1191 		DBG(4, "extra TX%d ready, csr %04x\n", epnum, tx_csr);
1192 		return;
1193 	}
1194 
1195 	if (is_dma_capable() && dma && !status) {
1196 		/*
1197 		 * DMA has completed.  But if we're using DMA mode 1 (multi
1198 		 * packet DMA), we need a terminal TXPKTRDY interrupt before
1199 		 * we can consider this transfer completed, lest we trash
1200 		 * its last packet when writing the next URB's data.  So we
1201 		 * switch back to mode 0 to get that interrupt; we'll come
1202 		 * back here once it happens.
1203 		 */
1204 		if (tx_csr & MUSB_TXCSR_DMAMODE) {
1205 			/*
1206 			 * We shouldn't clear DMAMODE with DMAENAB set; so
1207 			 * clear them in a safe order.  That should be OK
1208 			 * once TXPKTRDY has been set (and I've never seen
1209 			 * it being 0 at this moment -- DMA interrupt latency
1210 			 * is significant) but if it hasn't been then we have
1211 			 * no choice but to stop being polite and ignore the
1212 			 * programmer's guide... :-)
1213 			 *
1214 			 * Note that we must write TXCSR with TXPKTRDY cleared
1215 			 * in order not to re-trigger the packet send (this bit
1216 			 * can't be cleared by CPU), and there's another caveat:
1217 			 * TXPKTRDY may be set shortly and then cleared in the
1218 			 * double-buffered FIFO mode, so we do an extra TXCSR
1219 			 * read for debouncing...
1220 			 */
1221 			tx_csr &= musb_readw(epio, MUSB_TXCSR);
1222 			if (tx_csr & MUSB_TXCSR_TXPKTRDY) {
1223 				tx_csr &= ~(MUSB_TXCSR_DMAENAB |
1224 					    MUSB_TXCSR_TXPKTRDY);
1225 				musb_writew(epio, MUSB_TXCSR,
1226 					    tx_csr | MUSB_TXCSR_H_WZC_BITS);
1227 			}
1228 			tx_csr &= ~(MUSB_TXCSR_DMAMODE |
1229 				    MUSB_TXCSR_TXPKTRDY);
1230 			musb_writew(epio, MUSB_TXCSR,
1231 				    tx_csr | MUSB_TXCSR_H_WZC_BITS);
1232 
1233 			/*
1234 			 * There is no guarantee that we'll get an interrupt
1235 			 * after clearing DMAMODE as we might have done this
1236 			 * too late (after TXPKTRDY was cleared by controller).
1237 			 * Re-read TXCSR as we have spoiled its previous value.
1238 			 */
1239 			tx_csr = musb_readw(epio, MUSB_TXCSR);
1240 		}
1241 
1242 		/*
1243 		 * We may get here from a DMA completion or TXPKTRDY interrupt.
1244 		 * In any case, we must check the FIFO status here and bail out
1245 		 * only if the FIFO still has data -- that should prevent the
1246 		 * "missed" TXPKTRDY interrupts and deal with double-buffered
1247 		 * FIFO mode too...
1248 		 */
1249 		if (tx_csr & (MUSB_TXCSR_FIFONOTEMPTY | MUSB_TXCSR_TXPKTRDY)) {
1250 			DBG(2, "DMA complete but packet still in FIFO, "
1251 			    "CSR %04x\n", tx_csr);
1252 			return;
1253 		}
1254 	}
1255 
1256 	if (!status || dma || usb_pipeisoc(pipe)) {
1257 		if (dma)
1258 			length = dma->actual_len;
1259 		else
1260 			length = qh->segsize;
1261 		qh->offset += length;
1262 
1263 		if (usb_pipeisoc(pipe)) {
1264 			struct usb_iso_packet_descriptor	*d;
1265 
1266 			d = urb->iso_frame_desc + qh->iso_idx;
1267 			d->actual_length = length;
1268 			d->status = status;
1269 			if (++qh->iso_idx >= urb->number_of_packets) {
1270 				done = true;
1271 			} else {
1272 				d++;
1273 				offset = d->offset;
1274 				length = d->length;
1275 			}
1276 		} else if (dma) {
1277 			done = true;
1278 		} else {
1279 			/* see if we need to send more data, or ZLP */
1280 			if (qh->segsize < qh->maxpacket)
1281 				done = true;
1282 			else if (qh->offset == urb->transfer_buffer_length
1283 					&& !(urb->transfer_flags
1284 						& URB_ZERO_PACKET))
1285 				done = true;
1286 			if (!done) {
1287 				offset = qh->offset;
1288 				length = urb->transfer_buffer_length - offset;
1289 			}
1290 		}
1291 	}
1292 
1293 	/* urb->status != -EINPROGRESS means request has been faulted,
1294 	 * so we must abort this transfer after cleanup
1295 	 */
1296 	if (urb->status != -EINPROGRESS) {
1297 		done = true;
1298 		if (status == 0)
1299 			status = urb->status;
1300 	}
1301 
1302 	if (done) {
1303 		/* set status */
1304 		urb->status = status;
1305 		urb->actual_length = qh->offset;
1306 		musb_advance_schedule(musb, urb, hw_ep, USB_DIR_OUT);
1307 		return;
1308 	} else	if (usb_pipeisoc(pipe) && dma) {
1309 		if (musb_tx_dma_program(musb->dma_controller, hw_ep, qh, urb,
1310 				offset, length)) {
1311 			if (is_cppi_enabled() || tusb_dma_omap())
1312 				musb_h_tx_dma_start(hw_ep);
1313 			return;
1314 		}
1315 	} else	if (tx_csr & MUSB_TXCSR_DMAENAB) {
1316 		DBG(1, "not complete, but DMA enabled?\n");
1317 		return;
1318 	}
1319 
1320 	/*
1321 	 * PIO: start next packet in this URB.
1322 	 *
1323 	 * REVISIT: some docs say that when hw_ep->tx_double_buffered,
1324 	 * (and presumably, FIFO is not half-full) we should write *two*
1325 	 * packets before updating TXCSR; other docs disagree...
1326 	 */
1327 	if (length > qh->maxpacket)
1328 		length = qh->maxpacket;
1329 	musb_write_fifo(hw_ep, length, urb->transfer_buffer + offset);
1330 	qh->segsize = length;
1331 
1332 	musb_ep_select(mbase, epnum);
1333 	musb_writew(epio, MUSB_TXCSR,
1334 			MUSB_TXCSR_H_WZC_BITS | MUSB_TXCSR_TXPKTRDY);
1335 }
1336 
1337 
1338 #ifdef CONFIG_USB_INVENTRA_DMA
1339 
1340 /* Host side RX (IN) using Mentor DMA works as follows:
1341 	submit_urb ->
1342 		- if queue was empty, ProgramEndpoint
1343 		- first IN token is sent out (by setting ReqPkt)
1344 	LinuxIsr -> RxReady()
1345 	/\	=> first packet is received
1346 	|	- Set in mode 0 (DmaEnab, ~ReqPkt)
1347 	|		-> DMA Isr (transfer complete) -> RxReady()
1348 	|		    - Ack receive (~RxPktRdy), turn off DMA (~DmaEnab)
1349 	|		    - if urb not complete, send next IN token (ReqPkt)
1350 	|			   |		else complete urb.
1351 	|			   |
1352 	---------------------------
1353  *
1354  * Nuances of mode 1:
1355  *	For short packets, no ack (+RxPktRdy) is sent automatically
1356  *	(even if AutoClear is ON)
1357  *	For full packets, ack (~RxPktRdy) and next IN token (+ReqPkt) is sent
1358  *	automatically => major problem, as collecting the next packet becomes
1359  *	difficult. Hence mode 1 is not used.
1360  *
1361  * REVISIT
1362  *	All we care about at this driver level is that
1363  *       (a) all URBs terminate with REQPKT cleared and fifo(s) empty;
1364  *       (b) termination conditions are: short RX, or buffer full;
1365  *       (c) fault modes include
1366  *           - iff URB_SHORT_NOT_OK, short RX status is -EREMOTEIO.
1367  *             (and that endpoint's dma queue stops immediately)
1368  *           - overflow (full, PLUS more bytes in the terminal packet)
1369  *
1370  *	So for example, usb-storage sets URB_SHORT_NOT_OK, and would
1371  *	thus be a great candidate for using mode 1 ... for all but the
1372  *	last packet of one URB's transfer.
1373  */
1374 
1375 #endif
1376 
1377 /* Schedule next QH from musb->in_bulk and move the current qh to
1378  * the end; avoids starvation for other endpoints.
1379  */
1380 static void musb_bulk_rx_nak_timeout(struct musb *musb, struct musb_hw_ep *ep)
1381 {
1382 	struct dma_channel	*dma;
1383 	struct urb		*urb;
1384 	void __iomem		*mbase = musb->mregs;
1385 	void __iomem		*epio = ep->regs;
1386 	struct musb_qh		*cur_qh, *next_qh;
1387 	u16			rx_csr;
1388 
1389 	musb_ep_select(mbase, ep->epnum);
1390 	dma = is_dma_capable() ? ep->rx_channel : NULL;
1391 
1392 	/* clear nak timeout bit */
1393 	rx_csr = musb_readw(epio, MUSB_RXCSR);
1394 	rx_csr |= MUSB_RXCSR_H_WZC_BITS;
1395 	rx_csr &= ~MUSB_RXCSR_DATAERROR;
1396 	musb_writew(epio, MUSB_RXCSR, rx_csr);
1397 
1398 	cur_qh = first_qh(&musb->in_bulk);
1399 	if (cur_qh) {
1400 		urb = next_urb(cur_qh);
1401 		if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1402 			dma->status = MUSB_DMA_STATUS_CORE_ABORT;
1403 			musb->dma_controller->channel_abort(dma);
1404 			urb->actual_length += dma->actual_len;
1405 			dma->actual_len = 0L;
1406 		}
1407 		musb_save_toggle(cur_qh, 1, urb);
1408 
1409 		/* move cur_qh to end of queue */
1410 		list_move_tail(&cur_qh->ring, &musb->in_bulk);
1411 
1412 		/* get the next qh from musb->in_bulk */
1413 		next_qh = first_qh(&musb->in_bulk);
1414 
1415 		/* set rx_reinit and schedule the next qh */
1416 		ep->rx_reinit = 1;
1417 		musb_start_urb(musb, 1, next_qh);
1418 	}
1419 }
1420 
1421 /*
1422  * Service an RX interrupt for the given IN endpoint; docs cover bulk, iso,
1423  * and high-bandwidth IN transfer cases.
1424  */
1425 void musb_host_rx(struct musb *musb, u8 epnum)
1426 {
1427 	struct urb		*urb;
1428 	struct musb_hw_ep	*hw_ep = musb->endpoints + epnum;
1429 	void __iomem		*epio = hw_ep->regs;
1430 	struct musb_qh		*qh = hw_ep->in_qh;
1431 	size_t			xfer_len;
1432 	void __iomem		*mbase = musb->mregs;
1433 	int			pipe;
1434 	u16			rx_csr, val;
1435 	bool			iso_err = false;
1436 	bool			done = false;
1437 	u32			status;
1438 	struct dma_channel	*dma;
1439 
1440 	musb_ep_select(mbase, epnum);
1441 
1442 	urb = next_urb(qh);
1443 	dma = is_dma_capable() ? hw_ep->rx_channel : NULL;
1444 	status = 0;
1445 	xfer_len = 0;
1446 
1447 	rx_csr = musb_readw(epio, MUSB_RXCSR);
1448 	val = rx_csr;
1449 
1450 	if (unlikely(!urb)) {
1451 		/* REVISIT -- THIS SHOULD NEVER HAPPEN ... but, at least
1452 		 * usbtest #11 (unlinks) triggers it regularly, sometimes
1453 		 * with fifo full.  (Only with DMA??)
1454 		 */
1455 		DBG(3, "BOGUS RX%d ready, csr %04x, count %d\n", epnum, val,
1456 			musb_readw(epio, MUSB_RXCOUNT));
1457 		musb_h_flush_rxfifo(hw_ep, MUSB_RXCSR_CLRDATATOG);
1458 		return;
1459 	}
1460 
1461 	pipe = urb->pipe;
1462 
1463 	DBG(5, "<== hw %d rxcsr %04x, urb actual %d (+dma %zu)\n",
1464 		epnum, rx_csr, urb->actual_length,
1465 		dma ? dma->actual_len : 0);
1466 
1467 	/* check for errors, concurrent stall & unlink is not really
1468 	 * handled yet! */
1469 	if (rx_csr & MUSB_RXCSR_H_RXSTALL) {
1470 		DBG(3, "RX end %d STALL\n", epnum);
1471 
1472 		/* stall; record URB status */
1473 		status = -EPIPE;
1474 
1475 	} else if (rx_csr & MUSB_RXCSR_H_ERROR) {
1476 		DBG(3, "end %d RX proto error\n", epnum);
1477 
1478 		status = -EPROTO;
1479 		musb_writeb(epio, MUSB_RXINTERVAL, 0);
1480 
1481 	} else if (rx_csr & MUSB_RXCSR_DATAERROR) {
1482 
1483 		if (USB_ENDPOINT_XFER_ISOC != qh->type) {
1484 			DBG(6, "RX end %d NAK timeout\n", epnum);
1485 
1486 			/* NOTE: NAKing is *NOT* an error, so we want to
1487 			 * continue.  Except ... if there's a request for
1488 			 * another QH, use that instead of starving it.
1489 			 *
1490 			 * Devices like Ethernet and serial adapters keep
1491 			 * reads posted at all times, which will starve
1492 			 * other devices without this logic.
1493 			 */
1494 			if (usb_pipebulk(urb->pipe)
1495 					&& qh->mux == 1
1496 					&& !list_is_singular(&musb->in_bulk)) {
1497 				musb_bulk_rx_nak_timeout(musb, hw_ep);
1498 				return;
1499 			}
1500 			musb_ep_select(mbase, epnum);
1501 			rx_csr |= MUSB_RXCSR_H_WZC_BITS;
1502 			rx_csr &= ~MUSB_RXCSR_DATAERROR;
1503 			musb_writew(epio, MUSB_RXCSR, rx_csr);
1504 
1505 			goto finish;
1506 		} else {
1507 			DBG(4, "RX end %d ISO data error\n", epnum);
1508 			/* packet error reported later */
1509 			iso_err = true;
1510 		}
1511 	} else if (rx_csr & MUSB_RXCSR_INCOMPRX) {
1512 		DBG(3, "end %d high bandwidth incomplete ISO packet RX\n",
1513 				epnum);
1514 		status = -EPROTO;
1515 	}
1516 
1517 	/* faults abort the transfer */
1518 	if (status) {
1519 		/* clean up dma and collect transfer count */
1520 		if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1521 			dma->status = MUSB_DMA_STATUS_CORE_ABORT;
1522 			(void) musb->dma_controller->channel_abort(dma);
1523 			xfer_len = dma->actual_len;
1524 		}
1525 		musb_h_flush_rxfifo(hw_ep, MUSB_RXCSR_CLRDATATOG);
1526 		musb_writeb(epio, MUSB_RXINTERVAL, 0);
1527 		done = true;
1528 		goto finish;
1529 	}
1530 
1531 	if (unlikely(dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY)) {
1532 		/* SHOULD NEVER HAPPEN ... but at least DaVinci has done it */
1533 		ERR("RX%d dma busy, csr %04x\n", epnum, rx_csr);
1534 		goto finish;
1535 	}
1536 
1537 	/* thorough shutdown for now ... given more precise fault handling
1538 	 * and better queueing support, we might keep a DMA pipeline going
1539 	 * while processing this irq for earlier completions.
1540 	 */
1541 
1542 	/* FIXME this is _way_ too much in-line logic for Mentor DMA */
1543 
1544 #ifndef CONFIG_USB_INVENTRA_DMA
1545 	if (rx_csr & MUSB_RXCSR_H_REQPKT)  {
1546 		/* REVISIT this happened for a while on some short reads...
1547 		 * the cleanup still needs investigation... looks bad...
1548 		 * and also duplicates dma cleanup code above ... plus,
1549 		 * shouldn't this be the "half full" double buffer case?
1550 		 */
1551 		if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1552 			dma->status = MUSB_DMA_STATUS_CORE_ABORT;
1553 			(void) musb->dma_controller->channel_abort(dma);
1554 			xfer_len = dma->actual_len;
1555 			done = true;
1556 		}
1557 
1558 		DBG(2, "RXCSR%d %04x, reqpkt, len %zu%s\n", epnum, rx_csr,
1559 				xfer_len, dma ? ", dma" : "");
1560 		rx_csr &= ~MUSB_RXCSR_H_REQPKT;
1561 
1562 		musb_ep_select(mbase, epnum);
1563 		musb_writew(epio, MUSB_RXCSR,
1564 				MUSB_RXCSR_H_WZC_BITS | rx_csr);
1565 	}
1566 #endif
1567 	if (dma && (rx_csr & MUSB_RXCSR_DMAENAB)) {
1568 		xfer_len = dma->actual_len;
1569 
1570 		val &= ~(MUSB_RXCSR_DMAENAB
1571 			| MUSB_RXCSR_H_AUTOREQ
1572 			| MUSB_RXCSR_AUTOCLEAR
1573 			| MUSB_RXCSR_RXPKTRDY);
1574 		musb_writew(hw_ep->regs, MUSB_RXCSR, val);
1575 
1576 #ifdef CONFIG_USB_INVENTRA_DMA
1577 		if (usb_pipeisoc(pipe)) {
1578 			struct usb_iso_packet_descriptor *d;
1579 
1580 			d = urb->iso_frame_desc + qh->iso_idx;
1581 			d->actual_length = xfer_len;
1582 
1583 			/* even if there was an error, we did the dma
1584 			 * for iso_frame_desc->length
1585 			 */
1586 			if (d->status != EILSEQ && d->status != -EOVERFLOW)
1587 				d->status = 0;
1588 
1589 			if (++qh->iso_idx >= urb->number_of_packets)
1590 				done = true;
1591 			else
1592 				done = false;
1593 
1594 		} else  {
1595 		/* done if urb buffer is full or short packet is recd */
1596 		done = (urb->actual_length + xfer_len >=
1597 				urb->transfer_buffer_length
1598 			|| dma->actual_len < qh->maxpacket);
1599 		}
1600 
1601 		/* send IN token for next packet, without AUTOREQ */
1602 		if (!done) {
1603 			val |= MUSB_RXCSR_H_REQPKT;
1604 			musb_writew(epio, MUSB_RXCSR,
1605 				MUSB_RXCSR_H_WZC_BITS | val);
1606 		}
1607 
1608 		DBG(4, "ep %d dma %s, rxcsr %04x, rxcount %d\n", epnum,
1609 			done ? "off" : "reset",
1610 			musb_readw(epio, MUSB_RXCSR),
1611 			musb_readw(epio, MUSB_RXCOUNT));
1612 #else
1613 		done = true;
1614 #endif
1615 	} else if (urb->status == -EINPROGRESS) {
1616 		/* if no errors, be sure a packet is ready for unloading */
1617 		if (unlikely(!(rx_csr & MUSB_RXCSR_RXPKTRDY))) {
1618 			status = -EPROTO;
1619 			ERR("Rx interrupt with no errors or packet!\n");
1620 
1621 			/* FIXME this is another "SHOULD NEVER HAPPEN" */
1622 
1623 /* SCRUB (RX) */
1624 			/* do the proper sequence to abort the transfer */
1625 			musb_ep_select(mbase, epnum);
1626 			val &= ~MUSB_RXCSR_H_REQPKT;
1627 			musb_writew(epio, MUSB_RXCSR, val);
1628 			goto finish;
1629 		}
1630 
1631 		/* we are expecting IN packets */
1632 #ifdef CONFIG_USB_INVENTRA_DMA
1633 		if (dma) {
1634 			struct dma_controller	*c;
1635 			u16			rx_count;
1636 			int			ret, length;
1637 			dma_addr_t		buf;
1638 
1639 			rx_count = musb_readw(epio, MUSB_RXCOUNT);
1640 
1641 			DBG(2, "RX%d count %d, buffer 0x%x len %d/%d\n",
1642 					epnum, rx_count,
1643 					urb->transfer_dma
1644 						+ urb->actual_length,
1645 					qh->offset,
1646 					urb->transfer_buffer_length);
1647 
1648 			c = musb->dma_controller;
1649 
1650 			if (usb_pipeisoc(pipe)) {
1651 				int d_status = 0;
1652 				struct usb_iso_packet_descriptor *d;
1653 
1654 				d = urb->iso_frame_desc + qh->iso_idx;
1655 
1656 				if (iso_err) {
1657 					d_status = -EILSEQ;
1658 					urb->error_count++;
1659 				}
1660 				if (rx_count > d->length) {
1661 					if (d_status == 0) {
1662 						d_status = -EOVERFLOW;
1663 						urb->error_count++;
1664 					}
1665 					DBG(2, "** OVERFLOW %d into %d\n",\
1666 					    rx_count, d->length);
1667 
1668 					length = d->length;
1669 				} else
1670 					length = rx_count;
1671 				d->status = d_status;
1672 				buf = urb->transfer_dma + d->offset;
1673 			} else {
1674 				length = rx_count;
1675 				buf = urb->transfer_dma +
1676 						urb->actual_length;
1677 			}
1678 
1679 			dma->desired_mode = 0;
1680 #ifdef USE_MODE1
1681 			/* because of the issue below, mode 1 will
1682 			 * only rarely behave with correct semantics.
1683 			 */
1684 			if ((urb->transfer_flags &
1685 						URB_SHORT_NOT_OK)
1686 				&& (urb->transfer_buffer_length -
1687 						urb->actual_length)
1688 					> qh->maxpacket)
1689 				dma->desired_mode = 1;
1690 			if (rx_count < hw_ep->max_packet_sz_rx) {
1691 				length = rx_count;
1692 				dma->desired_mode = 0;
1693 			} else {
1694 				length = urb->transfer_buffer_length;
1695 			}
1696 #endif
1697 
1698 /* Disadvantage of using mode 1:
1699  *	It's basically usable only for mass storage class; essentially all
1700  *	other protocols also terminate transfers on short packets.
1701  *
1702  * Details:
1703  *	An extra IN token is sent at the end of the transfer (due to AUTOREQ)
1704  *	If you try to use mode 1 for (transfer_buffer_length - 512), and try
1705  *	to use the extra IN token to grab the last packet using mode 0, then
1706  *	the problem is that you cannot be sure when the device will send the
1707  *	last packet and RxPktRdy set. Sometimes the packet is recd too soon
1708  *	such that it gets lost when RxCSR is re-set at the end of the mode 1
1709  *	transfer, while sometimes it is recd just a little late so that if you
1710  *	try to configure for mode 0 soon after the mode 1 transfer is
1711  *	completed, you will find rxcount 0. Okay, so you might think why not
1712  *	wait for an interrupt when the pkt is recd. Well, you won't get any!
1713  */
1714 
1715 			val = musb_readw(epio, MUSB_RXCSR);
1716 			val &= ~MUSB_RXCSR_H_REQPKT;
1717 
1718 			if (dma->desired_mode == 0)
1719 				val &= ~MUSB_RXCSR_H_AUTOREQ;
1720 			else
1721 				val |= MUSB_RXCSR_H_AUTOREQ;
1722 			val |= MUSB_RXCSR_DMAENAB;
1723 
1724 			/* autoclear shouldn't be set in high bandwidth */
1725 			if (qh->hb_mult == 1)
1726 				val |= MUSB_RXCSR_AUTOCLEAR;
1727 
1728 			musb_writew(epio, MUSB_RXCSR,
1729 				MUSB_RXCSR_H_WZC_BITS | val);
1730 
1731 			/* REVISIT if when actual_length != 0,
1732 			 * transfer_buffer_length needs to be
1733 			 * adjusted first...
1734 			 */
1735 			ret = c->channel_program(
1736 				dma, qh->maxpacket,
1737 				dma->desired_mode, buf, length);
1738 
1739 			if (!ret) {
1740 				c->channel_release(dma);
1741 				hw_ep->rx_channel = NULL;
1742 				dma = NULL;
1743 				/* REVISIT reset CSR */
1744 			}
1745 		}
1746 #endif	/* Mentor DMA */
1747 
1748 		if (!dma) {
1749 			done = musb_host_packet_rx(musb, urb,
1750 					epnum, iso_err);
1751 			DBG(6, "read %spacket\n", done ? "last " : "");
1752 		}
1753 	}
1754 
1755 finish:
1756 	urb->actual_length += xfer_len;
1757 	qh->offset += xfer_len;
1758 	if (done) {
1759 		if (urb->status == -EINPROGRESS)
1760 			urb->status = status;
1761 		musb_advance_schedule(musb, urb, hw_ep, USB_DIR_IN);
1762 	}
1763 }
1764 
1765 /* schedule nodes correspond to peripheral endpoints, like an OHCI QH.
1766  * the software schedule associates multiple such nodes with a given
1767  * host side hardware endpoint + direction; scheduling may activate
1768  * that hardware endpoint.
1769  */
1770 static int musb_schedule(
1771 	struct musb		*musb,
1772 	struct musb_qh		*qh,
1773 	int			is_in)
1774 {
1775 	int			idle;
1776 	int			best_diff;
1777 	int			best_end, epnum;
1778 	struct musb_hw_ep	*hw_ep = NULL;
1779 	struct list_head	*head = NULL;
1780 	u8			toggle;
1781 	u8			txtype;
1782 	struct urb		*urb = next_urb(qh);
1783 
1784 	/* use fixed hardware for control and bulk */
1785 	if (qh->type == USB_ENDPOINT_XFER_CONTROL) {
1786 		head = &musb->control;
1787 		hw_ep = musb->control_ep;
1788 		goto success;
1789 	}
1790 
1791 	/* else, periodic transfers get muxed to other endpoints */
1792 
1793 	/*
1794 	 * We know this qh hasn't been scheduled, so all we need to do
1795 	 * is choose which hardware endpoint to put it on ...
1796 	 *
1797 	 * REVISIT what we really want here is a regular schedule tree
1798 	 * like e.g. OHCI uses.
1799 	 */
1800 	best_diff = 4096;
1801 	best_end = -1;
1802 
1803 	for (epnum = 1, hw_ep = musb->endpoints + 1;
1804 			epnum < musb->nr_endpoints;
1805 			epnum++, hw_ep++) {
1806 		int	diff;
1807 
1808 		if (musb_ep_get_qh(hw_ep, is_in) != NULL)
1809 			continue;
1810 
1811 		if (hw_ep == musb->bulk_ep)
1812 			continue;
1813 
1814 		if (is_in)
1815 			diff = hw_ep->max_packet_sz_rx;
1816 		else
1817 			diff = hw_ep->max_packet_sz_tx;
1818 		diff -= (qh->maxpacket * qh->hb_mult);
1819 
1820 		if (diff >= 0 && best_diff > diff) {
1821 
1822 			/*
1823 			 * Mentor controller has a bug in that if we schedule
1824 			 * a BULK Tx transfer on an endpoint that had earlier
1825 			 * handled ISOC then the BULK transfer has to start on
1826 			 * a zero toggle.  If the BULK transfer starts on a 1
1827 			 * toggle then this transfer will fail as the mentor
1828 			 * controller starts the Bulk transfer on a 0 toggle
1829 			 * irrespective of the programming of the toggle bits
1830 			 * in the TXCSR register.  Check for this condition
1831 			 * while allocating the EP for a Tx Bulk transfer.  If
1832 			 * so skip this EP.
1833 			 */
1834 			hw_ep = musb->endpoints + epnum;
1835 			toggle = usb_gettoggle(urb->dev, qh->epnum, !is_in);
1836 			txtype = (musb_readb(hw_ep->regs, MUSB_TXTYPE)
1837 					>> 4) & 0x3;
1838 			if (!is_in && (qh->type == USB_ENDPOINT_XFER_BULK) &&
1839 				toggle && (txtype == USB_ENDPOINT_XFER_ISOC))
1840 				continue;
1841 
1842 			best_diff = diff;
1843 			best_end = epnum;
1844 		}
1845 	}
1846 	/* use bulk reserved ep1 if no other ep is free */
1847 	if (best_end < 0 && qh->type == USB_ENDPOINT_XFER_BULK) {
1848 		hw_ep = musb->bulk_ep;
1849 		if (is_in)
1850 			head = &musb->in_bulk;
1851 		else
1852 			head = &musb->out_bulk;
1853 
1854 		/* Enable bulk RX NAK timeout scheme when bulk requests are
1855 		 * multiplexed.  This scheme doen't work in high speed to full
1856 		 * speed scenario as NAK interrupts are not coming from a
1857 		 * full speed device connected to a high speed device.
1858 		 * NAK timeout interval is 8 (128 uframe or 16ms) for HS and
1859 		 * 4 (8 frame or 8ms) for FS device.
1860 		 */
1861 		if (is_in && qh->dev)
1862 			qh->intv_reg =
1863 				(USB_SPEED_HIGH == qh->dev->speed) ? 8 : 4;
1864 		goto success;
1865 	} else if (best_end < 0) {
1866 		return -ENOSPC;
1867 	}
1868 
1869 	idle = 1;
1870 	qh->mux = 0;
1871 	hw_ep = musb->endpoints + best_end;
1872 	DBG(4, "qh %p periodic slot %d\n", qh, best_end);
1873 success:
1874 	if (head) {
1875 		idle = list_empty(head);
1876 		list_add_tail(&qh->ring, head);
1877 		qh->mux = 1;
1878 	}
1879 	qh->hw_ep = hw_ep;
1880 	qh->hep->hcpriv = qh;
1881 	if (idle)
1882 		musb_start_urb(musb, is_in, qh);
1883 	return 0;
1884 }
1885 
1886 static int musb_urb_enqueue(
1887 	struct usb_hcd			*hcd,
1888 	struct urb			*urb,
1889 	gfp_t				mem_flags)
1890 {
1891 	unsigned long			flags;
1892 	struct musb			*musb = hcd_to_musb(hcd);
1893 	struct usb_host_endpoint	*hep = urb->ep;
1894 	struct musb_qh			*qh;
1895 	struct usb_endpoint_descriptor	*epd = &hep->desc;
1896 	int				ret;
1897 	unsigned			type_reg;
1898 	unsigned			interval;
1899 
1900 	/* host role must be active */
1901 	if (!is_host_active(musb) || !musb->is_active)
1902 		return -ENODEV;
1903 
1904 	spin_lock_irqsave(&musb->lock, flags);
1905 	ret = usb_hcd_link_urb_to_ep(hcd, urb);
1906 	qh = ret ? NULL : hep->hcpriv;
1907 	if (qh)
1908 		urb->hcpriv = qh;
1909 	spin_unlock_irqrestore(&musb->lock, flags);
1910 
1911 	/* DMA mapping was already done, if needed, and this urb is on
1912 	 * hep->urb_list now ... so we're done, unless hep wasn't yet
1913 	 * scheduled onto a live qh.
1914 	 *
1915 	 * REVISIT best to keep hep->hcpriv valid until the endpoint gets
1916 	 * disabled, testing for empty qh->ring and avoiding qh setup costs
1917 	 * except for the first urb queued after a config change.
1918 	 */
1919 	if (qh || ret)
1920 		return ret;
1921 
1922 	/* Allocate and initialize qh, minimizing the work done each time
1923 	 * hw_ep gets reprogrammed, or with irqs blocked.  Then schedule it.
1924 	 *
1925 	 * REVISIT consider a dedicated qh kmem_cache, so it's harder
1926 	 * for bugs in other kernel code to break this driver...
1927 	 */
1928 	qh = kzalloc(sizeof *qh, mem_flags);
1929 	if (!qh) {
1930 		spin_lock_irqsave(&musb->lock, flags);
1931 		usb_hcd_unlink_urb_from_ep(hcd, urb);
1932 		spin_unlock_irqrestore(&musb->lock, flags);
1933 		return -ENOMEM;
1934 	}
1935 
1936 	qh->hep = hep;
1937 	qh->dev = urb->dev;
1938 	INIT_LIST_HEAD(&qh->ring);
1939 	qh->is_ready = 1;
1940 
1941 	qh->maxpacket = le16_to_cpu(epd->wMaxPacketSize);
1942 	qh->type = usb_endpoint_type(epd);
1943 
1944 	/* Bits 11 & 12 of wMaxPacketSize encode high bandwidth multiplier.
1945 	 * Some musb cores don't support high bandwidth ISO transfers; and
1946 	 * we don't (yet!) support high bandwidth interrupt transfers.
1947 	 */
1948 	qh->hb_mult = 1 + ((qh->maxpacket >> 11) & 0x03);
1949 	if (qh->hb_mult > 1) {
1950 		int ok = (qh->type == USB_ENDPOINT_XFER_ISOC);
1951 
1952 		if (ok)
1953 			ok = (usb_pipein(urb->pipe) && musb->hb_iso_rx)
1954 				|| (usb_pipeout(urb->pipe) && musb->hb_iso_tx);
1955 		if (!ok) {
1956 			ret = -EMSGSIZE;
1957 			goto done;
1958 		}
1959 		qh->maxpacket &= 0x7ff;
1960 	}
1961 
1962 	qh->epnum = usb_endpoint_num(epd);
1963 
1964 	/* NOTE: urb->dev->devnum is wrong during SET_ADDRESS */
1965 	qh->addr_reg = (u8) usb_pipedevice(urb->pipe);
1966 
1967 	/* precompute rxtype/txtype/type0 register */
1968 	type_reg = (qh->type << 4) | qh->epnum;
1969 	switch (urb->dev->speed) {
1970 	case USB_SPEED_LOW:
1971 		type_reg |= 0xc0;
1972 		break;
1973 	case USB_SPEED_FULL:
1974 		type_reg |= 0x80;
1975 		break;
1976 	default:
1977 		type_reg |= 0x40;
1978 	}
1979 	qh->type_reg = type_reg;
1980 
1981 	/* Precompute RXINTERVAL/TXINTERVAL register */
1982 	switch (qh->type) {
1983 	case USB_ENDPOINT_XFER_INT:
1984 		/*
1985 		 * Full/low speeds use the  linear encoding,
1986 		 * high speed uses the logarithmic encoding.
1987 		 */
1988 		if (urb->dev->speed <= USB_SPEED_FULL) {
1989 			interval = max_t(u8, epd->bInterval, 1);
1990 			break;
1991 		}
1992 		/* FALLTHROUGH */
1993 	case USB_ENDPOINT_XFER_ISOC:
1994 		/* ISO always uses logarithmic encoding */
1995 		interval = min_t(u8, epd->bInterval, 16);
1996 		break;
1997 	default:
1998 		/* REVISIT we actually want to use NAK limits, hinting to the
1999 		 * transfer scheduling logic to try some other qh, e.g. try
2000 		 * for 2 msec first:
2001 		 *
2002 		 * interval = (USB_SPEED_HIGH == urb->dev->speed) ? 16 : 2;
2003 		 *
2004 		 * The downside of disabling this is that transfer scheduling
2005 		 * gets VERY unfair for nonperiodic transfers; a misbehaving
2006 		 * peripheral could make that hurt.  That's perfectly normal
2007 		 * for reads from network or serial adapters ... so we have
2008 		 * partial NAKlimit support for bulk RX.
2009 		 *
2010 		 * The upside of disabling it is simpler transfer scheduling.
2011 		 */
2012 		interval = 0;
2013 	}
2014 	qh->intv_reg = interval;
2015 
2016 	/* precompute addressing for external hub/tt ports */
2017 	if (musb->is_multipoint) {
2018 		struct usb_device	*parent = urb->dev->parent;
2019 
2020 		if (parent != hcd->self.root_hub) {
2021 			qh->h_addr_reg = (u8) parent->devnum;
2022 
2023 			/* set up tt info if needed */
2024 			if (urb->dev->tt) {
2025 				qh->h_port_reg = (u8) urb->dev->ttport;
2026 				if (urb->dev->tt->hub)
2027 					qh->h_addr_reg =
2028 						(u8) urb->dev->tt->hub->devnum;
2029 				if (urb->dev->tt->multi)
2030 					qh->h_addr_reg |= 0x80;
2031 			}
2032 		}
2033 	}
2034 
2035 	/* invariant: hep->hcpriv is null OR the qh that's already scheduled.
2036 	 * until we get real dma queues (with an entry for each urb/buffer),
2037 	 * we only have work to do in the former case.
2038 	 */
2039 	spin_lock_irqsave(&musb->lock, flags);
2040 	if (hep->hcpriv) {
2041 		/* some concurrent activity submitted another urb to hep...
2042 		 * odd, rare, error prone, but legal.
2043 		 */
2044 		kfree(qh);
2045 		ret = 0;
2046 	} else
2047 		ret = musb_schedule(musb, qh,
2048 				epd->bEndpointAddress & USB_ENDPOINT_DIR_MASK);
2049 
2050 	if (ret == 0) {
2051 		urb->hcpriv = qh;
2052 		/* FIXME set urb->start_frame for iso/intr, it's tested in
2053 		 * musb_start_urb(), but otherwise only konicawc cares ...
2054 		 */
2055 	}
2056 	spin_unlock_irqrestore(&musb->lock, flags);
2057 
2058 done:
2059 	if (ret != 0) {
2060 		spin_lock_irqsave(&musb->lock, flags);
2061 		usb_hcd_unlink_urb_from_ep(hcd, urb);
2062 		spin_unlock_irqrestore(&musb->lock, flags);
2063 		kfree(qh);
2064 	}
2065 	return ret;
2066 }
2067 
2068 
2069 /*
2070  * abort a transfer that's at the head of a hardware queue.
2071  * called with controller locked, irqs blocked
2072  * that hardware queue advances to the next transfer, unless prevented
2073  */
2074 static int musb_cleanup_urb(struct urb *urb, struct musb_qh *qh)
2075 {
2076 	struct musb_hw_ep	*ep = qh->hw_ep;
2077 	void __iomem		*epio = ep->regs;
2078 	unsigned		hw_end = ep->epnum;
2079 	void __iomem		*regs = ep->musb->mregs;
2080 	int			is_in = usb_pipein(urb->pipe);
2081 	int			status = 0;
2082 	u16			csr;
2083 
2084 	musb_ep_select(regs, hw_end);
2085 
2086 	if (is_dma_capable()) {
2087 		struct dma_channel	*dma;
2088 
2089 		dma = is_in ? ep->rx_channel : ep->tx_channel;
2090 		if (dma) {
2091 			status = ep->musb->dma_controller->channel_abort(dma);
2092 			DBG(status ? 1 : 3,
2093 				"abort %cX%d DMA for urb %p --> %d\n",
2094 				is_in ? 'R' : 'T', ep->epnum,
2095 				urb, status);
2096 			urb->actual_length += dma->actual_len;
2097 		}
2098 	}
2099 
2100 	/* turn off DMA requests, discard state, stop polling ... */
2101 	if (is_in) {
2102 		/* giveback saves bulk toggle */
2103 		csr = musb_h_flush_rxfifo(ep, 0);
2104 
2105 		/* REVISIT we still get an irq; should likely clear the
2106 		 * endpoint's irq status here to avoid bogus irqs.
2107 		 * clearing that status is platform-specific...
2108 		 */
2109 	} else if (ep->epnum) {
2110 		musb_h_tx_flush_fifo(ep);
2111 		csr = musb_readw(epio, MUSB_TXCSR);
2112 		csr &= ~(MUSB_TXCSR_AUTOSET
2113 			| MUSB_TXCSR_DMAENAB
2114 			| MUSB_TXCSR_H_RXSTALL
2115 			| MUSB_TXCSR_H_NAKTIMEOUT
2116 			| MUSB_TXCSR_H_ERROR
2117 			| MUSB_TXCSR_TXPKTRDY);
2118 		musb_writew(epio, MUSB_TXCSR, csr);
2119 		/* REVISIT may need to clear FLUSHFIFO ... */
2120 		musb_writew(epio, MUSB_TXCSR, csr);
2121 		/* flush cpu writebuffer */
2122 		csr = musb_readw(epio, MUSB_TXCSR);
2123 	} else  {
2124 		musb_h_ep0_flush_fifo(ep);
2125 	}
2126 	if (status == 0)
2127 		musb_advance_schedule(ep->musb, urb, ep, is_in);
2128 	return status;
2129 }
2130 
2131 static int musb_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
2132 {
2133 	struct musb		*musb = hcd_to_musb(hcd);
2134 	struct musb_qh		*qh;
2135 	unsigned long		flags;
2136 	int			is_in  = usb_pipein(urb->pipe);
2137 	int			ret;
2138 
2139 	DBG(4, "urb=%p, dev%d ep%d%s\n", urb,
2140 			usb_pipedevice(urb->pipe),
2141 			usb_pipeendpoint(urb->pipe),
2142 			is_in ? "in" : "out");
2143 
2144 	spin_lock_irqsave(&musb->lock, flags);
2145 	ret = usb_hcd_check_unlink_urb(hcd, urb, status);
2146 	if (ret)
2147 		goto done;
2148 
2149 	qh = urb->hcpriv;
2150 	if (!qh)
2151 		goto done;
2152 
2153 	/*
2154 	 * Any URB not actively programmed into endpoint hardware can be
2155 	 * immediately given back; that's any URB not at the head of an
2156 	 * endpoint queue, unless someday we get real DMA queues.  And even
2157 	 * if it's at the head, it might not be known to the hardware...
2158 	 *
2159 	 * Otherwise abort current transfer, pending DMA, etc.; urb->status
2160 	 * has already been updated.  This is a synchronous abort; it'd be
2161 	 * OK to hold off until after some IRQ, though.
2162 	 *
2163 	 * NOTE: qh is invalid unless !list_empty(&hep->urb_list)
2164 	 */
2165 	if (!qh->is_ready
2166 			|| urb->urb_list.prev != &qh->hep->urb_list
2167 			|| musb_ep_get_qh(qh->hw_ep, is_in) != qh) {
2168 		int	ready = qh->is_ready;
2169 
2170 		qh->is_ready = 0;
2171 		musb_giveback(musb, urb, 0);
2172 		qh->is_ready = ready;
2173 
2174 		/* If nothing else (usually musb_giveback) is using it
2175 		 * and its URB list has emptied, recycle this qh.
2176 		 */
2177 		if (ready && list_empty(&qh->hep->urb_list)) {
2178 			qh->hep->hcpriv = NULL;
2179 			list_del(&qh->ring);
2180 			kfree(qh);
2181 		}
2182 	} else
2183 		ret = musb_cleanup_urb(urb, qh);
2184 done:
2185 	spin_unlock_irqrestore(&musb->lock, flags);
2186 	return ret;
2187 }
2188 
2189 /* disable an endpoint */
2190 static void
2191 musb_h_disable(struct usb_hcd *hcd, struct usb_host_endpoint *hep)
2192 {
2193 	u8			is_in = hep->desc.bEndpointAddress & USB_DIR_IN;
2194 	unsigned long		flags;
2195 	struct musb		*musb = hcd_to_musb(hcd);
2196 	struct musb_qh		*qh;
2197 	struct urb		*urb;
2198 
2199 	spin_lock_irqsave(&musb->lock, flags);
2200 
2201 	qh = hep->hcpriv;
2202 	if (qh == NULL)
2203 		goto exit;
2204 
2205 	/* NOTE: qh is invalid unless !list_empty(&hep->urb_list) */
2206 
2207 	/* Kick the first URB off the hardware, if needed */
2208 	qh->is_ready = 0;
2209 	if (musb_ep_get_qh(qh->hw_ep, is_in) == qh) {
2210 		urb = next_urb(qh);
2211 
2212 		/* make software (then hardware) stop ASAP */
2213 		if (!urb->unlinked)
2214 			urb->status = -ESHUTDOWN;
2215 
2216 		/* cleanup */
2217 		musb_cleanup_urb(urb, qh);
2218 
2219 		/* Then nuke all the others ... and advance the
2220 		 * queue on hw_ep (e.g. bulk ring) when we're done.
2221 		 */
2222 		while (!list_empty(&hep->urb_list)) {
2223 			urb = next_urb(qh);
2224 			urb->status = -ESHUTDOWN;
2225 			musb_advance_schedule(musb, urb, qh->hw_ep, is_in);
2226 		}
2227 	} else {
2228 		/* Just empty the queue; the hardware is busy with
2229 		 * other transfers, and since !qh->is_ready nothing
2230 		 * will activate any of these as it advances.
2231 		 */
2232 		while (!list_empty(&hep->urb_list))
2233 			musb_giveback(musb, next_urb(qh), -ESHUTDOWN);
2234 
2235 		hep->hcpriv = NULL;
2236 		list_del(&qh->ring);
2237 		kfree(qh);
2238 	}
2239 exit:
2240 	spin_unlock_irqrestore(&musb->lock, flags);
2241 }
2242 
2243 static int musb_h_get_frame_number(struct usb_hcd *hcd)
2244 {
2245 	struct musb	*musb = hcd_to_musb(hcd);
2246 
2247 	return musb_readw(musb->mregs, MUSB_FRAME);
2248 }
2249 
2250 static int musb_h_start(struct usb_hcd *hcd)
2251 {
2252 	struct musb	*musb = hcd_to_musb(hcd);
2253 
2254 	/* NOTE: musb_start() is called when the hub driver turns
2255 	 * on port power, or when (OTG) peripheral starts.
2256 	 */
2257 	hcd->state = HC_STATE_RUNNING;
2258 	musb->port1_status = 0;
2259 	return 0;
2260 }
2261 
2262 static void musb_h_stop(struct usb_hcd *hcd)
2263 {
2264 	musb_stop(hcd_to_musb(hcd));
2265 	hcd->state = HC_STATE_HALT;
2266 }
2267 
2268 static int musb_bus_suspend(struct usb_hcd *hcd)
2269 {
2270 	struct musb	*musb = hcd_to_musb(hcd);
2271 	u8		devctl;
2272 
2273 	if (!is_host_active(musb))
2274 		return 0;
2275 
2276 	switch (musb->xceiv->state) {
2277 	case OTG_STATE_A_SUSPEND:
2278 		return 0;
2279 	case OTG_STATE_A_WAIT_VRISE:
2280 		/* ID could be grounded even if there's no device
2281 		 * on the other end of the cable.  NOTE that the
2282 		 * A_WAIT_VRISE timers are messy with MUSB...
2283 		 */
2284 		devctl = musb_readb(musb->mregs, MUSB_DEVCTL);
2285 		if ((devctl & MUSB_DEVCTL_VBUS) == MUSB_DEVCTL_VBUS)
2286 			musb->xceiv->state = OTG_STATE_A_WAIT_BCON;
2287 		break;
2288 	default:
2289 		break;
2290 	}
2291 
2292 	if (musb->is_active) {
2293 		WARNING("trying to suspend as %s while active\n",
2294 				otg_state_string(musb));
2295 		return -EBUSY;
2296 	} else
2297 		return 0;
2298 }
2299 
2300 static int musb_bus_resume(struct usb_hcd *hcd)
2301 {
2302 	/* resuming child port does the work */
2303 	return 0;
2304 }
2305 
2306 const struct hc_driver musb_hc_driver = {
2307 	.description		= "musb-hcd",
2308 	.product_desc		= "MUSB HDRC host driver",
2309 	.hcd_priv_size		= sizeof(struct musb),
2310 	.flags			= HCD_USB2 | HCD_MEMORY,
2311 
2312 	/* not using irq handler or reset hooks from usbcore, since
2313 	 * those must be shared with peripheral code for OTG configs
2314 	 */
2315 
2316 	.start			= musb_h_start,
2317 	.stop			= musb_h_stop,
2318 
2319 	.get_frame_number	= musb_h_get_frame_number,
2320 
2321 	.urb_enqueue		= musb_urb_enqueue,
2322 	.urb_dequeue		= musb_urb_dequeue,
2323 	.endpoint_disable	= musb_h_disable,
2324 
2325 	.hub_status_data	= musb_hub_status_data,
2326 	.hub_control		= musb_hub_control,
2327 	.bus_suspend		= musb_bus_suspend,
2328 	.bus_resume		= musb_bus_resume,
2329 	/* .start_port_reset	= NULL, */
2330 	/* .hub_irq_enable	= NULL, */
2331 };
2332