xref: /linux/drivers/usb/musb/musb_host.c (revision 81ec4e4a5116c2bccec2dd1d350ceb4372846ba8)
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 /* caller owns controller lock, irqs are blocked */
299 static void
300 __musb_giveback(struct musb *musb, struct urb *urb, int status)
301 __releases(musb->lock)
302 __acquires(musb->lock)
303 {
304 	DBG(({ int level; switch (status) {
305 				case 0:
306 					level = 4;
307 					break;
308 				/* common/boring faults */
309 				case -EREMOTEIO:
310 				case -ESHUTDOWN:
311 				case -ECONNRESET:
312 				case -EPIPE:
313 					level = 3;
314 					break;
315 				default:
316 					level = 2;
317 					break;
318 				}; level; }),
319 			"complete %p %pF (%d), dev%d ep%d%s, %d/%d\n",
320 			urb, urb->complete, status,
321 			usb_pipedevice(urb->pipe),
322 			usb_pipeendpoint(urb->pipe),
323 			usb_pipein(urb->pipe) ? "in" : "out",
324 			urb->actual_length, urb->transfer_buffer_length
325 			);
326 
327 	usb_hcd_unlink_urb_from_ep(musb_to_hcd(musb), urb);
328 	spin_unlock(&musb->lock);
329 	usb_hcd_giveback_urb(musb_to_hcd(musb), urb, status);
330 	spin_lock(&musb->lock);
331 }
332 
333 /* For bulk/interrupt endpoints only */
334 static inline void musb_save_toggle(struct musb_qh *qh, int is_in,
335 				    struct urb *urb)
336 {
337 	void __iomem		*epio = qh->hw_ep->regs;
338 	u16			csr;
339 
340 	/*
341 	 * FIXME: the current Mentor DMA code seems to have
342 	 * problems getting toggle correct.
343 	 */
344 
345 	if (is_in)
346 		csr = musb_readw(epio, MUSB_RXCSR) & MUSB_RXCSR_H_DATATOGGLE;
347 	else
348 		csr = musb_readw(epio, MUSB_TXCSR) & MUSB_TXCSR_H_DATATOGGLE;
349 
350 	usb_settoggle(urb->dev, qh->epnum, !is_in, csr ? 1 : 0);
351 }
352 
353 /* caller owns controller lock, irqs are blocked */
354 static struct musb_qh *
355 musb_giveback(struct musb_qh *qh, struct urb *urb, int status)
356 {
357 	struct musb_hw_ep	*ep = qh->hw_ep;
358 	struct musb		*musb = ep->musb;
359 	int			is_in = usb_pipein(urb->pipe);
360 	int			ready = qh->is_ready;
361 
362 	/* save toggle eagerly, for paranoia */
363 	switch (qh->type) {
364 	case USB_ENDPOINT_XFER_BULK:
365 	case USB_ENDPOINT_XFER_INT:
366 		musb_save_toggle(qh, is_in, urb);
367 		break;
368 	case USB_ENDPOINT_XFER_ISOC:
369 		if (status == 0 && urb->error_count)
370 			status = -EXDEV;
371 		break;
372 	}
373 
374 	qh->is_ready = 0;
375 	__musb_giveback(musb, urb, status);
376 	qh->is_ready = ready;
377 
378 	/* reclaim resources (and bandwidth) ASAP; deschedule it, and
379 	 * invalidate qh as soon as list_empty(&hep->urb_list)
380 	 */
381 	if (list_empty(&qh->hep->urb_list)) {
382 		struct list_head	*head;
383 
384 		if (is_in)
385 			ep->rx_reinit = 1;
386 		else
387 			ep->tx_reinit = 1;
388 
389 		/* Clobber old pointers to this qh */
390 		musb_ep_set_qh(ep, is_in, NULL);
391 		qh->hep->hcpriv = NULL;
392 
393 		switch (qh->type) {
394 
395 		case USB_ENDPOINT_XFER_CONTROL:
396 		case USB_ENDPOINT_XFER_BULK:
397 			/* fifo policy for these lists, except that NAKing
398 			 * should rotate a qh to the end (for fairness).
399 			 */
400 			if (qh->mux == 1) {
401 				head = qh->ring.prev;
402 				list_del(&qh->ring);
403 				kfree(qh);
404 				qh = first_qh(head);
405 				break;
406 			}
407 
408 		case USB_ENDPOINT_XFER_ISOC:
409 		case USB_ENDPOINT_XFER_INT:
410 			/* this is where periodic bandwidth should be
411 			 * de-allocated if it's tracked and allocated;
412 			 * and where we'd update the schedule tree...
413 			 */
414 			kfree(qh);
415 			qh = NULL;
416 			break;
417 		}
418 	}
419 	return qh;
420 }
421 
422 /*
423  * Advance this hardware endpoint's queue, completing the specified urb and
424  * advancing to either the next urb queued to that qh, or else invalidating
425  * that qh and advancing to the next qh scheduled after the current one.
426  *
427  * Context: caller owns controller lock, irqs are blocked
428  */
429 static void
430 musb_advance_schedule(struct musb *musb, struct urb *urb,
431 		struct musb_hw_ep *hw_ep, int is_in)
432 {
433 	struct musb_qh		*qh = musb_ep_get_qh(hw_ep, is_in);
434 
435 	if (urb->status == -EINPROGRESS)
436 		qh = musb_giveback(qh, urb, 0);
437 	else
438 		qh = musb_giveback(qh, urb, urb->status);
439 
440 	if (qh != NULL && qh->is_ready) {
441 		DBG(4, "... next ep%d %cX urb %p\n",
442 				hw_ep->epnum, is_in ? 'R' : 'T',
443 				next_urb(qh));
444 		musb_start_urb(musb, is_in, qh);
445 	}
446 }
447 
448 static u16 musb_h_flush_rxfifo(struct musb_hw_ep *hw_ep, u16 csr)
449 {
450 	/* we don't want fifo to fill itself again;
451 	 * ignore dma (various models),
452 	 * leave toggle alone (may not have been saved yet)
453 	 */
454 	csr |= MUSB_RXCSR_FLUSHFIFO | MUSB_RXCSR_RXPKTRDY;
455 	csr &= ~(MUSB_RXCSR_H_REQPKT
456 		| MUSB_RXCSR_H_AUTOREQ
457 		| MUSB_RXCSR_AUTOCLEAR);
458 
459 	/* write 2x to allow double buffering */
460 	musb_writew(hw_ep->regs, MUSB_RXCSR, csr);
461 	musb_writew(hw_ep->regs, MUSB_RXCSR, csr);
462 
463 	/* flush writebuffer */
464 	return musb_readw(hw_ep->regs, MUSB_RXCSR);
465 }
466 
467 /*
468  * PIO RX for a packet (or part of it).
469  */
470 static bool
471 musb_host_packet_rx(struct musb *musb, struct urb *urb, u8 epnum, u8 iso_err)
472 {
473 	u16			rx_count;
474 	u8			*buf;
475 	u16			csr;
476 	bool			done = false;
477 	u32			length;
478 	int			do_flush = 0;
479 	struct musb_hw_ep	*hw_ep = musb->endpoints + epnum;
480 	void __iomem		*epio = hw_ep->regs;
481 	struct musb_qh		*qh = hw_ep->in_qh;
482 	int			pipe = urb->pipe;
483 	void			*buffer = urb->transfer_buffer;
484 
485 	/* musb_ep_select(mbase, epnum); */
486 	rx_count = musb_readw(epio, MUSB_RXCOUNT);
487 	DBG(3, "RX%d count %d, buffer %p len %d/%d\n", epnum, rx_count,
488 			urb->transfer_buffer, qh->offset,
489 			urb->transfer_buffer_length);
490 
491 	/* unload FIFO */
492 	if (usb_pipeisoc(pipe)) {
493 		int					status = 0;
494 		struct usb_iso_packet_descriptor	*d;
495 
496 		if (iso_err) {
497 			status = -EILSEQ;
498 			urb->error_count++;
499 		}
500 
501 		d = urb->iso_frame_desc + qh->iso_idx;
502 		buf = buffer + d->offset;
503 		length = d->length;
504 		if (rx_count > length) {
505 			if (status == 0) {
506 				status = -EOVERFLOW;
507 				urb->error_count++;
508 			}
509 			DBG(2, "** OVERFLOW %d into %d\n", rx_count, length);
510 			do_flush = 1;
511 		} else
512 			length = rx_count;
513 		urb->actual_length += length;
514 		d->actual_length = length;
515 
516 		d->status = status;
517 
518 		/* see if we are done */
519 		done = (++qh->iso_idx >= urb->number_of_packets);
520 	} else {
521 		/* non-isoch */
522 		buf = buffer + qh->offset;
523 		length = urb->transfer_buffer_length - qh->offset;
524 		if (rx_count > length) {
525 			if (urb->status == -EINPROGRESS)
526 				urb->status = -EOVERFLOW;
527 			DBG(2, "** OVERFLOW %d into %d\n", rx_count, length);
528 			do_flush = 1;
529 		} else
530 			length = rx_count;
531 		urb->actual_length += length;
532 		qh->offset += length;
533 
534 		/* see if we are done */
535 		done = (urb->actual_length == urb->transfer_buffer_length)
536 			|| (rx_count < qh->maxpacket)
537 			|| (urb->status != -EINPROGRESS);
538 		if (done
539 				&& (urb->status == -EINPROGRESS)
540 				&& (urb->transfer_flags & URB_SHORT_NOT_OK)
541 				&& (urb->actual_length
542 					< urb->transfer_buffer_length))
543 			urb->status = -EREMOTEIO;
544 	}
545 
546 	musb_read_fifo(hw_ep, length, buf);
547 
548 	csr = musb_readw(epio, MUSB_RXCSR);
549 	csr |= MUSB_RXCSR_H_WZC_BITS;
550 	if (unlikely(do_flush))
551 		musb_h_flush_rxfifo(hw_ep, csr);
552 	else {
553 		/* REVISIT this assumes AUTOCLEAR is never set */
554 		csr &= ~(MUSB_RXCSR_RXPKTRDY | MUSB_RXCSR_H_REQPKT);
555 		if (!done)
556 			csr |= MUSB_RXCSR_H_REQPKT;
557 		musb_writew(epio, MUSB_RXCSR, csr);
558 	}
559 
560 	return done;
561 }
562 
563 /* we don't always need to reinit a given side of an endpoint...
564  * when we do, use tx/rx reinit routine and then construct a new CSR
565  * to address data toggle, NYET, and DMA or PIO.
566  *
567  * it's possible that driver bugs (especially for DMA) or aborting a
568  * transfer might have left the endpoint busier than it should be.
569  * the busy/not-empty tests are basically paranoia.
570  */
571 static void
572 musb_rx_reinit(struct musb *musb, struct musb_qh *qh, struct musb_hw_ep *ep)
573 {
574 	u16	csr;
575 
576 	/* NOTE:  we know the "rx" fifo reinit never triggers for ep0.
577 	 * That always uses tx_reinit since ep0 repurposes TX register
578 	 * offsets; the initial SETUP packet is also a kind of OUT.
579 	 */
580 
581 	/* if programmed for Tx, put it in RX mode */
582 	if (ep->is_shared_fifo) {
583 		csr = musb_readw(ep->regs, MUSB_TXCSR);
584 		if (csr & MUSB_TXCSR_MODE) {
585 			musb_h_tx_flush_fifo(ep);
586 			csr = musb_readw(ep->regs, MUSB_TXCSR);
587 			musb_writew(ep->regs, MUSB_TXCSR,
588 				    csr | MUSB_TXCSR_FRCDATATOG);
589 		}
590 
591 		/*
592 		 * Clear the MODE bit (and everything else) to enable Rx.
593 		 * NOTE: we mustn't clear the DMAMODE bit before DMAENAB.
594 		 */
595 		if (csr & MUSB_TXCSR_DMAMODE)
596 			musb_writew(ep->regs, MUSB_TXCSR, MUSB_TXCSR_DMAMODE);
597 		musb_writew(ep->regs, MUSB_TXCSR, 0);
598 
599 	/* scrub all previous state, clearing toggle */
600 	} else {
601 		csr = musb_readw(ep->regs, MUSB_RXCSR);
602 		if (csr & MUSB_RXCSR_RXPKTRDY)
603 			WARNING("rx%d, packet/%d ready?\n", ep->epnum,
604 				musb_readw(ep->regs, MUSB_RXCOUNT));
605 
606 		musb_h_flush_rxfifo(ep, MUSB_RXCSR_CLRDATATOG);
607 	}
608 
609 	/* target addr and (for multipoint) hub addr/port */
610 	if (musb->is_multipoint) {
611 		musb_write_rxfunaddr(ep->target_regs, qh->addr_reg);
612 		musb_write_rxhubaddr(ep->target_regs, qh->h_addr_reg);
613 		musb_write_rxhubport(ep->target_regs, qh->h_port_reg);
614 
615 	} else
616 		musb_writeb(musb->mregs, MUSB_FADDR, qh->addr_reg);
617 
618 	/* protocol/endpoint, interval/NAKlimit, i/o size */
619 	musb_writeb(ep->regs, MUSB_RXTYPE, qh->type_reg);
620 	musb_writeb(ep->regs, MUSB_RXINTERVAL, qh->intv_reg);
621 	/* NOTE: bulk combining rewrites high bits of maxpacket */
622 	musb_writew(ep->regs, MUSB_RXMAXP, qh->maxpacket);
623 
624 	ep->rx_reinit = 0;
625 }
626 
627 static bool musb_tx_dma_program(struct dma_controller *dma,
628 		struct musb_hw_ep *hw_ep, struct musb_qh *qh,
629 		struct urb *urb, u32 offset, u32 length)
630 {
631 	struct dma_channel	*channel = hw_ep->tx_channel;
632 	void __iomem		*epio = hw_ep->regs;
633 	u16			pkt_size = qh->maxpacket;
634 	u16			csr;
635 	u8			mode;
636 
637 #ifdef	CONFIG_USB_INVENTRA_DMA
638 	if (length > channel->max_len)
639 		length = channel->max_len;
640 
641 	csr = musb_readw(epio, MUSB_TXCSR);
642 	if (length > pkt_size) {
643 		mode = 1;
644 		csr |= MUSB_TXCSR_AUTOSET
645 			| MUSB_TXCSR_DMAMODE
646 			| MUSB_TXCSR_DMAENAB;
647 	} else {
648 		mode = 0;
649 		csr &= ~(MUSB_TXCSR_AUTOSET | MUSB_TXCSR_DMAMODE);
650 		csr |= MUSB_TXCSR_DMAENAB; /* against programmer's guide */
651 	}
652 	channel->desired_mode = mode;
653 	musb_writew(epio, MUSB_TXCSR, csr);
654 #else
655 	if (!is_cppi_enabled() && !tusb_dma_omap())
656 		return false;
657 
658 	channel->actual_len = 0;
659 
660 	/*
661 	 * TX uses "RNDIS" mode automatically but needs help
662 	 * to identify the zero-length-final-packet case.
663 	 */
664 	mode = (urb->transfer_flags & URB_ZERO_PACKET) ? 1 : 0;
665 #endif
666 
667 	qh->segsize = length;
668 
669 	if (!dma->channel_program(channel, pkt_size, mode,
670 			urb->transfer_dma + offset, length)) {
671 		dma->channel_release(channel);
672 		hw_ep->tx_channel = NULL;
673 
674 		csr = musb_readw(epio, MUSB_TXCSR);
675 		csr &= ~(MUSB_TXCSR_AUTOSET | MUSB_TXCSR_DMAENAB);
676 		musb_writew(epio, MUSB_TXCSR, csr | MUSB_TXCSR_H_WZC_BITS);
677 		return false;
678 	}
679 	return true;
680 }
681 
682 /*
683  * Program an HDRC endpoint as per the given URB
684  * Context: irqs blocked, controller lock held
685  */
686 static void musb_ep_program(struct musb *musb, u8 epnum,
687 			struct urb *urb, int is_out,
688 			u8 *buf, u32 offset, u32 len)
689 {
690 	struct dma_controller	*dma_controller;
691 	struct dma_channel	*dma_channel;
692 	u8			dma_ok;
693 	void __iomem		*mbase = musb->mregs;
694 	struct musb_hw_ep	*hw_ep = musb->endpoints + epnum;
695 	void __iomem		*epio = hw_ep->regs;
696 	struct musb_qh		*qh = musb_ep_get_qh(hw_ep, !is_out);
697 	u16			packet_sz = qh->maxpacket;
698 
699 	DBG(3, "%s hw%d urb %p spd%d dev%d ep%d%s "
700 				"h_addr%02x h_port%02x bytes %d\n",
701 			is_out ? "-->" : "<--",
702 			epnum, urb, urb->dev->speed,
703 			qh->addr_reg, qh->epnum, is_out ? "out" : "in",
704 			qh->h_addr_reg, qh->h_port_reg,
705 			len);
706 
707 	musb_ep_select(mbase, epnum);
708 
709 	/* candidate for DMA? */
710 	dma_controller = musb->dma_controller;
711 	if (is_dma_capable() && epnum && dma_controller) {
712 		dma_channel = is_out ? hw_ep->tx_channel : hw_ep->rx_channel;
713 		if (!dma_channel) {
714 			dma_channel = dma_controller->channel_alloc(
715 					dma_controller, hw_ep, is_out);
716 			if (is_out)
717 				hw_ep->tx_channel = dma_channel;
718 			else
719 				hw_ep->rx_channel = dma_channel;
720 		}
721 	} else
722 		dma_channel = NULL;
723 
724 	/* make sure we clear DMAEnab, autoSet bits from previous run */
725 
726 	/* OUT/transmit/EP0 or IN/receive? */
727 	if (is_out) {
728 		u16	csr;
729 		u16	int_txe;
730 		u16	load_count;
731 
732 		csr = musb_readw(epio, MUSB_TXCSR);
733 
734 		/* disable interrupt in case we flush */
735 		int_txe = musb_readw(mbase, MUSB_INTRTXE);
736 		musb_writew(mbase, MUSB_INTRTXE, int_txe & ~(1 << epnum));
737 
738 		/* general endpoint setup */
739 		if (epnum) {
740 			/* flush all old state, set default */
741 			musb_h_tx_flush_fifo(hw_ep);
742 
743 			/*
744 			 * We must not clear the DMAMODE bit before or in
745 			 * the same cycle with the DMAENAB bit, so we clear
746 			 * the latter first...
747 			 */
748 			csr &= ~(MUSB_TXCSR_H_NAKTIMEOUT
749 					| MUSB_TXCSR_AUTOSET
750 					| MUSB_TXCSR_DMAENAB
751 					| MUSB_TXCSR_FRCDATATOG
752 					| MUSB_TXCSR_H_RXSTALL
753 					| MUSB_TXCSR_H_ERROR
754 					| MUSB_TXCSR_TXPKTRDY
755 					);
756 			csr |= MUSB_TXCSR_MODE;
757 
758 			if (usb_gettoggle(urb->dev, qh->epnum, 1))
759 				csr |= MUSB_TXCSR_H_WR_DATATOGGLE
760 					| MUSB_TXCSR_H_DATATOGGLE;
761 			else
762 				csr |= MUSB_TXCSR_CLRDATATOG;
763 
764 			musb_writew(epio, MUSB_TXCSR, csr);
765 			/* REVISIT may need to clear FLUSHFIFO ... */
766 			csr &= ~MUSB_TXCSR_DMAMODE;
767 			musb_writew(epio, MUSB_TXCSR, csr);
768 			csr = musb_readw(epio, MUSB_TXCSR);
769 		} else {
770 			/* endpoint 0: just flush */
771 			musb_h_ep0_flush_fifo(hw_ep);
772 		}
773 
774 		/* target addr and (for multipoint) hub addr/port */
775 		if (musb->is_multipoint) {
776 			musb_write_txfunaddr(mbase, epnum, qh->addr_reg);
777 			musb_write_txhubaddr(mbase, epnum, qh->h_addr_reg);
778 			musb_write_txhubport(mbase, epnum, qh->h_port_reg);
779 /* FIXME if !epnum, do the same for RX ... */
780 		} else
781 			musb_writeb(mbase, MUSB_FADDR, qh->addr_reg);
782 
783 		/* protocol/endpoint/interval/NAKlimit */
784 		if (epnum) {
785 			musb_writeb(epio, MUSB_TXTYPE, qh->type_reg);
786 			if (can_bulk_split(musb, qh->type))
787 				musb_writew(epio, MUSB_TXMAXP,
788 					packet_sz
789 					| ((hw_ep->max_packet_sz_tx /
790 						packet_sz) - 1) << 11);
791 			else
792 				musb_writew(epio, MUSB_TXMAXP,
793 					packet_sz);
794 			musb_writeb(epio, MUSB_TXINTERVAL, qh->intv_reg);
795 		} else {
796 			musb_writeb(epio, MUSB_NAKLIMIT0, qh->intv_reg);
797 			if (musb->is_multipoint)
798 				musb_writeb(epio, MUSB_TYPE0,
799 						qh->type_reg);
800 		}
801 
802 		if (can_bulk_split(musb, qh->type))
803 			load_count = min((u32) hw_ep->max_packet_sz_tx,
804 						len);
805 		else
806 			load_count = min((u32) packet_sz, len);
807 
808 		if (dma_channel && musb_tx_dma_program(dma_controller,
809 					hw_ep, qh, urb, offset, len))
810 			load_count = 0;
811 
812 		if (load_count) {
813 			/* PIO to load FIFO */
814 			qh->segsize = load_count;
815 			musb_write_fifo(hw_ep, load_count, buf);
816 		}
817 
818 		/* re-enable interrupt */
819 		musb_writew(mbase, MUSB_INTRTXE, int_txe);
820 
821 	/* IN/receive */
822 	} else {
823 		u16	csr;
824 
825 		if (hw_ep->rx_reinit) {
826 			musb_rx_reinit(musb, qh, hw_ep);
827 
828 			/* init new state: toggle and NYET, maybe DMA later */
829 			if (usb_gettoggle(urb->dev, qh->epnum, 0))
830 				csr = MUSB_RXCSR_H_WR_DATATOGGLE
831 					| MUSB_RXCSR_H_DATATOGGLE;
832 			else
833 				csr = 0;
834 			if (qh->type == USB_ENDPOINT_XFER_INT)
835 				csr |= MUSB_RXCSR_DISNYET;
836 
837 		} else {
838 			csr = musb_readw(hw_ep->regs, MUSB_RXCSR);
839 
840 			if (csr & (MUSB_RXCSR_RXPKTRDY
841 					| MUSB_RXCSR_DMAENAB
842 					| MUSB_RXCSR_H_REQPKT))
843 				ERR("broken !rx_reinit, ep%d csr %04x\n",
844 						hw_ep->epnum, csr);
845 
846 			/* scrub any stale state, leaving toggle alone */
847 			csr &= MUSB_RXCSR_DISNYET;
848 		}
849 
850 		/* kick things off */
851 
852 		if ((is_cppi_enabled() || tusb_dma_omap()) && dma_channel) {
853 			/* candidate for DMA */
854 			if (dma_channel) {
855 				dma_channel->actual_len = 0L;
856 				qh->segsize = len;
857 
858 				/* AUTOREQ is in a DMA register */
859 				musb_writew(hw_ep->regs, MUSB_RXCSR, csr);
860 				csr = musb_readw(hw_ep->regs,
861 						MUSB_RXCSR);
862 
863 				/* unless caller treats short rx transfers as
864 				 * errors, we dare not queue multiple transfers.
865 				 */
866 				dma_ok = dma_controller->channel_program(
867 						dma_channel, packet_sz,
868 						!(urb->transfer_flags
869 							& URB_SHORT_NOT_OK),
870 						urb->transfer_dma + offset,
871 						qh->segsize);
872 				if (!dma_ok) {
873 					dma_controller->channel_release(
874 							dma_channel);
875 					hw_ep->rx_channel = NULL;
876 					dma_channel = NULL;
877 				} else
878 					csr |= MUSB_RXCSR_DMAENAB;
879 			}
880 		}
881 
882 		csr |= MUSB_RXCSR_H_REQPKT;
883 		DBG(7, "RXCSR%d := %04x\n", epnum, csr);
884 		musb_writew(hw_ep->regs, MUSB_RXCSR, csr);
885 		csr = musb_readw(hw_ep->regs, MUSB_RXCSR);
886 	}
887 }
888 
889 
890 /*
891  * Service the default endpoint (ep0) as host.
892  * Return true until it's time to start the status stage.
893  */
894 static bool musb_h_ep0_continue(struct musb *musb, u16 len, struct urb *urb)
895 {
896 	bool			 more = false;
897 	u8			*fifo_dest = NULL;
898 	u16			fifo_count = 0;
899 	struct musb_hw_ep	*hw_ep = musb->control_ep;
900 	struct musb_qh		*qh = hw_ep->in_qh;
901 	struct usb_ctrlrequest	*request;
902 
903 	switch (musb->ep0_stage) {
904 	case MUSB_EP0_IN:
905 		fifo_dest = urb->transfer_buffer + urb->actual_length;
906 		fifo_count = min_t(size_t, len, urb->transfer_buffer_length -
907 				   urb->actual_length);
908 		if (fifo_count < len)
909 			urb->status = -EOVERFLOW;
910 
911 		musb_read_fifo(hw_ep, fifo_count, fifo_dest);
912 
913 		urb->actual_length += fifo_count;
914 		if (len < qh->maxpacket) {
915 			/* always terminate on short read; it's
916 			 * rarely reported as an error.
917 			 */
918 		} else if (urb->actual_length <
919 				urb->transfer_buffer_length)
920 			more = true;
921 		break;
922 	case MUSB_EP0_START:
923 		request = (struct usb_ctrlrequest *) urb->setup_packet;
924 
925 		if (!request->wLength) {
926 			DBG(4, "start no-DATA\n");
927 			break;
928 		} else if (request->bRequestType & USB_DIR_IN) {
929 			DBG(4, "start IN-DATA\n");
930 			musb->ep0_stage = MUSB_EP0_IN;
931 			more = true;
932 			break;
933 		} else {
934 			DBG(4, "start OUT-DATA\n");
935 			musb->ep0_stage = MUSB_EP0_OUT;
936 			more = true;
937 		}
938 		/* FALLTHROUGH */
939 	case MUSB_EP0_OUT:
940 		fifo_count = min_t(size_t, qh->maxpacket,
941 				   urb->transfer_buffer_length -
942 				   urb->actual_length);
943 		if (fifo_count) {
944 			fifo_dest = (u8 *) (urb->transfer_buffer
945 					+ urb->actual_length);
946 			DBG(3, "Sending %d byte%s to ep0 fifo %p\n",
947 					fifo_count,
948 					(fifo_count == 1) ? "" : "s",
949 					fifo_dest);
950 			musb_write_fifo(hw_ep, fifo_count, fifo_dest);
951 
952 			urb->actual_length += fifo_count;
953 			more = true;
954 		}
955 		break;
956 	default:
957 		ERR("bogus ep0 stage %d\n", musb->ep0_stage);
958 		break;
959 	}
960 
961 	return more;
962 }
963 
964 /*
965  * Handle default endpoint interrupt as host. Only called in IRQ time
966  * from musb_interrupt().
967  *
968  * called with controller irqlocked
969  */
970 irqreturn_t musb_h_ep0_irq(struct musb *musb)
971 {
972 	struct urb		*urb;
973 	u16			csr, len;
974 	int			status = 0;
975 	void __iomem		*mbase = musb->mregs;
976 	struct musb_hw_ep	*hw_ep = musb->control_ep;
977 	void __iomem		*epio = hw_ep->regs;
978 	struct musb_qh		*qh = hw_ep->in_qh;
979 	bool			complete = false;
980 	irqreturn_t		retval = IRQ_NONE;
981 
982 	/* ep0 only has one queue, "in" */
983 	urb = next_urb(qh);
984 
985 	musb_ep_select(mbase, 0);
986 	csr = musb_readw(epio, MUSB_CSR0);
987 	len = (csr & MUSB_CSR0_RXPKTRDY)
988 			? musb_readb(epio, MUSB_COUNT0)
989 			: 0;
990 
991 	DBG(4, "<== csr0 %04x, qh %p, count %d, urb %p, stage %d\n",
992 		csr, qh, len, urb, musb->ep0_stage);
993 
994 	/* if we just did status stage, we are done */
995 	if (MUSB_EP0_STATUS == musb->ep0_stage) {
996 		retval = IRQ_HANDLED;
997 		complete = true;
998 	}
999 
1000 	/* prepare status */
1001 	if (csr & MUSB_CSR0_H_RXSTALL) {
1002 		DBG(6, "STALLING ENDPOINT\n");
1003 		status = -EPIPE;
1004 
1005 	} else if (csr & MUSB_CSR0_H_ERROR) {
1006 		DBG(2, "no response, csr0 %04x\n", csr);
1007 		status = -EPROTO;
1008 
1009 	} else if (csr & MUSB_CSR0_H_NAKTIMEOUT) {
1010 		DBG(2, "control NAK timeout\n");
1011 
1012 		/* NOTE:  this code path would be a good place to PAUSE a
1013 		 * control transfer, if another one is queued, so that
1014 		 * ep0 is more likely to stay busy.  That's already done
1015 		 * for bulk RX transfers.
1016 		 *
1017 		 * if (qh->ring.next != &musb->control), then
1018 		 * we have a candidate... NAKing is *NOT* an error
1019 		 */
1020 		musb_writew(epio, MUSB_CSR0, 0);
1021 		retval = IRQ_HANDLED;
1022 	}
1023 
1024 	if (status) {
1025 		DBG(6, "aborting\n");
1026 		retval = IRQ_HANDLED;
1027 		if (urb)
1028 			urb->status = status;
1029 		complete = true;
1030 
1031 		/* use the proper sequence to abort the transfer */
1032 		if (csr & MUSB_CSR0_H_REQPKT) {
1033 			csr &= ~MUSB_CSR0_H_REQPKT;
1034 			musb_writew(epio, MUSB_CSR0, csr);
1035 			csr &= ~MUSB_CSR0_H_NAKTIMEOUT;
1036 			musb_writew(epio, MUSB_CSR0, csr);
1037 		} else {
1038 			musb_h_ep0_flush_fifo(hw_ep);
1039 		}
1040 
1041 		musb_writeb(epio, MUSB_NAKLIMIT0, 0);
1042 
1043 		/* clear it */
1044 		musb_writew(epio, MUSB_CSR0, 0);
1045 	}
1046 
1047 	if (unlikely(!urb)) {
1048 		/* stop endpoint since we have no place for its data, this
1049 		 * SHOULD NEVER HAPPEN! */
1050 		ERR("no URB for end 0\n");
1051 
1052 		musb_h_ep0_flush_fifo(hw_ep);
1053 		goto done;
1054 	}
1055 
1056 	if (!complete) {
1057 		/* call common logic and prepare response */
1058 		if (musb_h_ep0_continue(musb, len, urb)) {
1059 			/* more packets required */
1060 			csr = (MUSB_EP0_IN == musb->ep0_stage)
1061 				?  MUSB_CSR0_H_REQPKT : MUSB_CSR0_TXPKTRDY;
1062 		} else {
1063 			/* data transfer complete; perform status phase */
1064 			if (usb_pipeout(urb->pipe)
1065 					|| !urb->transfer_buffer_length)
1066 				csr = MUSB_CSR0_H_STATUSPKT
1067 					| MUSB_CSR0_H_REQPKT;
1068 			else
1069 				csr = MUSB_CSR0_H_STATUSPKT
1070 					| MUSB_CSR0_TXPKTRDY;
1071 
1072 			/* flag status stage */
1073 			musb->ep0_stage = MUSB_EP0_STATUS;
1074 
1075 			DBG(5, "ep0 STATUS, csr %04x\n", csr);
1076 
1077 		}
1078 		musb_writew(epio, MUSB_CSR0, csr);
1079 		retval = IRQ_HANDLED;
1080 	} else
1081 		musb->ep0_stage = MUSB_EP0_IDLE;
1082 
1083 	/* call completion handler if done */
1084 	if (complete)
1085 		musb_advance_schedule(musb, urb, hw_ep, 1);
1086 done:
1087 	return retval;
1088 }
1089 
1090 
1091 #ifdef CONFIG_USB_INVENTRA_DMA
1092 
1093 /* Host side TX (OUT) using Mentor DMA works as follows:
1094 	submit_urb ->
1095 		- if queue was empty, Program Endpoint
1096 		- ... which starts DMA to fifo in mode 1 or 0
1097 
1098 	DMA Isr (transfer complete) -> TxAvail()
1099 		- Stop DMA (~DmaEnab)	(<--- Alert ... currently happens
1100 					only in musb_cleanup_urb)
1101 		- TxPktRdy has to be set in mode 0 or for
1102 			short packets in mode 1.
1103 */
1104 
1105 #endif
1106 
1107 /* Service a Tx-Available or dma completion irq for the endpoint */
1108 void musb_host_tx(struct musb *musb, u8 epnum)
1109 {
1110 	int			pipe;
1111 	bool			done = false;
1112 	u16			tx_csr;
1113 	size_t			length = 0;
1114 	size_t			offset = 0;
1115 	struct musb_hw_ep	*hw_ep = musb->endpoints + epnum;
1116 	void __iomem		*epio = hw_ep->regs;
1117 	struct musb_qh		*qh = hw_ep->out_qh;
1118 	struct urb		*urb = next_urb(qh);
1119 	u32			status = 0;
1120 	void __iomem		*mbase = musb->mregs;
1121 	struct dma_channel	*dma;
1122 
1123 	musb_ep_select(mbase, epnum);
1124 	tx_csr = musb_readw(epio, MUSB_TXCSR);
1125 
1126 	/* with CPPI, DMA sometimes triggers "extra" irqs */
1127 	if (!urb) {
1128 		DBG(4, "extra TX%d ready, csr %04x\n", epnum, tx_csr);
1129 		return;
1130 	}
1131 
1132 	pipe = urb->pipe;
1133 	dma = is_dma_capable() ? hw_ep->tx_channel : NULL;
1134 	DBG(4, "OUT/TX%d end, csr %04x%s\n", epnum, tx_csr,
1135 			dma ? ", dma" : "");
1136 
1137 	/* check for errors */
1138 	if (tx_csr & MUSB_TXCSR_H_RXSTALL) {
1139 		/* dma was disabled, fifo flushed */
1140 		DBG(3, "TX end %d stall\n", epnum);
1141 
1142 		/* stall; record URB status */
1143 		status = -EPIPE;
1144 
1145 	} else if (tx_csr & MUSB_TXCSR_H_ERROR) {
1146 		/* (NON-ISO) dma was disabled, fifo flushed */
1147 		DBG(3, "TX 3strikes on ep=%d\n", epnum);
1148 
1149 		status = -ETIMEDOUT;
1150 
1151 	} else if (tx_csr & MUSB_TXCSR_H_NAKTIMEOUT) {
1152 		DBG(6, "TX end=%d device not responding\n", epnum);
1153 
1154 		/* NOTE:  this code path would be a good place to PAUSE a
1155 		 * transfer, if there's some other (nonperiodic) tx urb
1156 		 * that could use this fifo.  (dma complicates it...)
1157 		 * That's already done for bulk RX transfers.
1158 		 *
1159 		 * if (bulk && qh->ring.next != &musb->out_bulk), then
1160 		 * we have a candidate... NAKing is *NOT* an error
1161 		 */
1162 		musb_ep_select(mbase, epnum);
1163 		musb_writew(epio, MUSB_TXCSR,
1164 				MUSB_TXCSR_H_WZC_BITS
1165 				| MUSB_TXCSR_TXPKTRDY);
1166 		return;
1167 	}
1168 
1169 	if (status) {
1170 		if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1171 			dma->status = MUSB_DMA_STATUS_CORE_ABORT;
1172 			(void) musb->dma_controller->channel_abort(dma);
1173 		}
1174 
1175 		/* do the proper sequence to abort the transfer in the
1176 		 * usb core; the dma engine should already be stopped.
1177 		 */
1178 		musb_h_tx_flush_fifo(hw_ep);
1179 		tx_csr &= ~(MUSB_TXCSR_AUTOSET
1180 				| MUSB_TXCSR_DMAENAB
1181 				| MUSB_TXCSR_H_ERROR
1182 				| MUSB_TXCSR_H_RXSTALL
1183 				| MUSB_TXCSR_H_NAKTIMEOUT
1184 				);
1185 
1186 		musb_ep_select(mbase, epnum);
1187 		musb_writew(epio, MUSB_TXCSR, tx_csr);
1188 		/* REVISIT may need to clear FLUSHFIFO ... */
1189 		musb_writew(epio, MUSB_TXCSR, tx_csr);
1190 		musb_writeb(epio, MUSB_TXINTERVAL, 0);
1191 
1192 		done = true;
1193 	}
1194 
1195 	/* second cppi case */
1196 	if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1197 		DBG(4, "extra TX%d ready, csr %04x\n", epnum, tx_csr);
1198 		return;
1199 	}
1200 
1201 	if (is_dma_capable() && dma && !status) {
1202 		/*
1203 		 * DMA has completed.  But if we're using DMA mode 1 (multi
1204 		 * packet DMA), we need a terminal TXPKTRDY interrupt before
1205 		 * we can consider this transfer completed, lest we trash
1206 		 * its last packet when writing the next URB's data.  So we
1207 		 * switch back to mode 0 to get that interrupt; we'll come
1208 		 * back here once it happens.
1209 		 */
1210 		if (tx_csr & MUSB_TXCSR_DMAMODE) {
1211 			/*
1212 			 * We shouldn't clear DMAMODE with DMAENAB set; so
1213 			 * clear them in a safe order.  That should be OK
1214 			 * once TXPKTRDY has been set (and I've never seen
1215 			 * it being 0 at this moment -- DMA interrupt latency
1216 			 * is significant) but if it hasn't been then we have
1217 			 * no choice but to stop being polite and ignore the
1218 			 * programmer's guide... :-)
1219 			 *
1220 			 * Note that we must write TXCSR with TXPKTRDY cleared
1221 			 * in order not to re-trigger the packet send (this bit
1222 			 * can't be cleared by CPU), and there's another caveat:
1223 			 * TXPKTRDY may be set shortly and then cleared in the
1224 			 * double-buffered FIFO mode, so we do an extra TXCSR
1225 			 * read for debouncing...
1226 			 */
1227 			tx_csr &= musb_readw(epio, MUSB_TXCSR);
1228 			if (tx_csr & MUSB_TXCSR_TXPKTRDY) {
1229 				tx_csr &= ~(MUSB_TXCSR_DMAENAB |
1230 					    MUSB_TXCSR_TXPKTRDY);
1231 				musb_writew(epio, MUSB_TXCSR,
1232 					    tx_csr | MUSB_TXCSR_H_WZC_BITS);
1233 			}
1234 			tx_csr &= ~(MUSB_TXCSR_DMAMODE |
1235 				    MUSB_TXCSR_TXPKTRDY);
1236 			musb_writew(epio, MUSB_TXCSR,
1237 				    tx_csr | MUSB_TXCSR_H_WZC_BITS);
1238 
1239 			/*
1240 			 * There is no guarantee that we'll get an interrupt
1241 			 * after clearing DMAMODE as we might have done this
1242 			 * too late (after TXPKTRDY was cleared by controller).
1243 			 * Re-read TXCSR as we have spoiled its previous value.
1244 			 */
1245 			tx_csr = musb_readw(epio, MUSB_TXCSR);
1246 		}
1247 
1248 		/*
1249 		 * We may get here from a DMA completion or TXPKTRDY interrupt.
1250 		 * In any case, we must check the FIFO status here and bail out
1251 		 * only if the FIFO still has data -- that should prevent the
1252 		 * "missed" TXPKTRDY interrupts and deal with double-buffered
1253 		 * FIFO mode too...
1254 		 */
1255 		if (tx_csr & (MUSB_TXCSR_FIFONOTEMPTY | MUSB_TXCSR_TXPKTRDY)) {
1256 			DBG(2, "DMA complete but packet still in FIFO, "
1257 			    "CSR %04x\n", tx_csr);
1258 			return;
1259 		}
1260 	}
1261 
1262 	if (!status || dma || usb_pipeisoc(pipe)) {
1263 		if (dma)
1264 			length = dma->actual_len;
1265 		else
1266 			length = qh->segsize;
1267 		qh->offset += length;
1268 
1269 		if (usb_pipeisoc(pipe)) {
1270 			struct usb_iso_packet_descriptor	*d;
1271 
1272 			d = urb->iso_frame_desc + qh->iso_idx;
1273 			d->actual_length = length;
1274 			d->status = status;
1275 			if (++qh->iso_idx >= urb->number_of_packets) {
1276 				done = true;
1277 			} else {
1278 				d++;
1279 				offset = d->offset;
1280 				length = d->length;
1281 			}
1282 		} else if (dma) {
1283 			done = true;
1284 		} else {
1285 			/* see if we need to send more data, or ZLP */
1286 			if (qh->segsize < qh->maxpacket)
1287 				done = true;
1288 			else if (qh->offset == urb->transfer_buffer_length
1289 					&& !(urb->transfer_flags
1290 						& URB_ZERO_PACKET))
1291 				done = true;
1292 			if (!done) {
1293 				offset = qh->offset;
1294 				length = urb->transfer_buffer_length - offset;
1295 			}
1296 		}
1297 	}
1298 
1299 	/* urb->status != -EINPROGRESS means request has been faulted,
1300 	 * so we must abort this transfer after cleanup
1301 	 */
1302 	if (urb->status != -EINPROGRESS) {
1303 		done = true;
1304 		if (status == 0)
1305 			status = urb->status;
1306 	}
1307 
1308 	if (done) {
1309 		/* set status */
1310 		urb->status = status;
1311 		urb->actual_length = qh->offset;
1312 		musb_advance_schedule(musb, urb, hw_ep, USB_DIR_OUT);
1313 		return;
1314 	} else	if (usb_pipeisoc(pipe) && dma) {
1315 		if (musb_tx_dma_program(musb->dma_controller, hw_ep, qh, urb,
1316 				offset, length))
1317 			return;
1318 	} else	if (tx_csr & MUSB_TXCSR_DMAENAB) {
1319 		DBG(1, "not complete, but DMA enabled?\n");
1320 		return;
1321 	}
1322 
1323 	/*
1324 	 * PIO: start next packet in this URB.
1325 	 *
1326 	 * REVISIT: some docs say that when hw_ep->tx_double_buffered,
1327 	 * (and presumably, FIFO is not half-full) we should write *two*
1328 	 * packets before updating TXCSR; other docs disagree...
1329 	 */
1330 	if (length > qh->maxpacket)
1331 		length = qh->maxpacket;
1332 	musb_write_fifo(hw_ep, length, urb->transfer_buffer + offset);
1333 	qh->segsize = length;
1334 
1335 	musb_ep_select(mbase, epnum);
1336 	musb_writew(epio, MUSB_TXCSR,
1337 			MUSB_TXCSR_H_WZC_BITS | MUSB_TXCSR_TXPKTRDY);
1338 }
1339 
1340 
1341 #ifdef CONFIG_USB_INVENTRA_DMA
1342 
1343 /* Host side RX (IN) using Mentor DMA works as follows:
1344 	submit_urb ->
1345 		- if queue was empty, ProgramEndpoint
1346 		- first IN token is sent out (by setting ReqPkt)
1347 	LinuxIsr -> RxReady()
1348 	/\	=> first packet is received
1349 	|	- Set in mode 0 (DmaEnab, ~ReqPkt)
1350 	|		-> DMA Isr (transfer complete) -> RxReady()
1351 	|		    - Ack receive (~RxPktRdy), turn off DMA (~DmaEnab)
1352 	|		    - if urb not complete, send next IN token (ReqPkt)
1353 	|			   |		else complete urb.
1354 	|			   |
1355 	---------------------------
1356  *
1357  * Nuances of mode 1:
1358  *	For short packets, no ack (+RxPktRdy) is sent automatically
1359  *	(even if AutoClear is ON)
1360  *	For full packets, ack (~RxPktRdy) and next IN token (+ReqPkt) is sent
1361  *	automatically => major problem, as collecting the next packet becomes
1362  *	difficult. Hence mode 1 is not used.
1363  *
1364  * REVISIT
1365  *	All we care about at this driver level is that
1366  *       (a) all URBs terminate with REQPKT cleared and fifo(s) empty;
1367  *       (b) termination conditions are: short RX, or buffer full;
1368  *       (c) fault modes include
1369  *           - iff URB_SHORT_NOT_OK, short RX status is -EREMOTEIO.
1370  *             (and that endpoint's dma queue stops immediately)
1371  *           - overflow (full, PLUS more bytes in the terminal packet)
1372  *
1373  *	So for example, usb-storage sets URB_SHORT_NOT_OK, and would
1374  *	thus be a great candidate for using mode 1 ... for all but the
1375  *	last packet of one URB's transfer.
1376  */
1377 
1378 #endif
1379 
1380 /* Schedule next QH from musb->in_bulk and move the current qh to
1381  * the end; avoids starvation for other endpoints.
1382  */
1383 static void musb_bulk_rx_nak_timeout(struct musb *musb, struct musb_hw_ep *ep)
1384 {
1385 	struct dma_channel	*dma;
1386 	struct urb		*urb;
1387 	void __iomem		*mbase = musb->mregs;
1388 	void __iomem		*epio = ep->regs;
1389 	struct musb_qh		*cur_qh, *next_qh;
1390 	u16			rx_csr;
1391 
1392 	musb_ep_select(mbase, ep->epnum);
1393 	dma = is_dma_capable() ? ep->rx_channel : NULL;
1394 
1395 	/* clear nak timeout bit */
1396 	rx_csr = musb_readw(epio, MUSB_RXCSR);
1397 	rx_csr |= MUSB_RXCSR_H_WZC_BITS;
1398 	rx_csr &= ~MUSB_RXCSR_DATAERROR;
1399 	musb_writew(epio, MUSB_RXCSR, rx_csr);
1400 
1401 	cur_qh = first_qh(&musb->in_bulk);
1402 	if (cur_qh) {
1403 		urb = next_urb(cur_qh);
1404 		if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1405 			dma->status = MUSB_DMA_STATUS_CORE_ABORT;
1406 			musb->dma_controller->channel_abort(dma);
1407 			urb->actual_length += dma->actual_len;
1408 			dma->actual_len = 0L;
1409 		}
1410 		musb_save_toggle(cur_qh, 1, urb);
1411 
1412 		/* move cur_qh to end of queue */
1413 		list_move_tail(&cur_qh->ring, &musb->in_bulk);
1414 
1415 		/* get the next qh from musb->in_bulk */
1416 		next_qh = first_qh(&musb->in_bulk);
1417 
1418 		/* set rx_reinit and schedule the next qh */
1419 		ep->rx_reinit = 1;
1420 		musb_start_urb(musb, 1, next_qh);
1421 	}
1422 }
1423 
1424 /*
1425  * Service an RX interrupt for the given IN endpoint; docs cover bulk, iso,
1426  * and high-bandwidth IN transfer cases.
1427  */
1428 void musb_host_rx(struct musb *musb, u8 epnum)
1429 {
1430 	struct urb		*urb;
1431 	struct musb_hw_ep	*hw_ep = musb->endpoints + epnum;
1432 	void __iomem		*epio = hw_ep->regs;
1433 	struct musb_qh		*qh = hw_ep->in_qh;
1434 	size_t			xfer_len;
1435 	void __iomem		*mbase = musb->mregs;
1436 	int			pipe;
1437 	u16			rx_csr, val;
1438 	bool			iso_err = false;
1439 	bool			done = false;
1440 	u32			status;
1441 	struct dma_channel	*dma;
1442 
1443 	musb_ep_select(mbase, epnum);
1444 
1445 	urb = next_urb(qh);
1446 	dma = is_dma_capable() ? hw_ep->rx_channel : NULL;
1447 	status = 0;
1448 	xfer_len = 0;
1449 
1450 	rx_csr = musb_readw(epio, MUSB_RXCSR);
1451 	val = rx_csr;
1452 
1453 	if (unlikely(!urb)) {
1454 		/* REVISIT -- THIS SHOULD NEVER HAPPEN ... but, at least
1455 		 * usbtest #11 (unlinks) triggers it regularly, sometimes
1456 		 * with fifo full.  (Only with DMA??)
1457 		 */
1458 		DBG(3, "BOGUS RX%d ready, csr %04x, count %d\n", epnum, val,
1459 			musb_readw(epio, MUSB_RXCOUNT));
1460 		musb_h_flush_rxfifo(hw_ep, MUSB_RXCSR_CLRDATATOG);
1461 		return;
1462 	}
1463 
1464 	pipe = urb->pipe;
1465 
1466 	DBG(5, "<== hw %d rxcsr %04x, urb actual %d (+dma %zu)\n",
1467 		epnum, rx_csr, urb->actual_length,
1468 		dma ? dma->actual_len : 0);
1469 
1470 	/* check for errors, concurrent stall & unlink is not really
1471 	 * handled yet! */
1472 	if (rx_csr & MUSB_RXCSR_H_RXSTALL) {
1473 		DBG(3, "RX end %d STALL\n", epnum);
1474 
1475 		/* stall; record URB status */
1476 		status = -EPIPE;
1477 
1478 	} else if (rx_csr & MUSB_RXCSR_H_ERROR) {
1479 		DBG(3, "end %d RX proto error\n", epnum);
1480 
1481 		status = -EPROTO;
1482 		musb_writeb(epio, MUSB_RXINTERVAL, 0);
1483 
1484 	} else if (rx_csr & MUSB_RXCSR_DATAERROR) {
1485 
1486 		if (USB_ENDPOINT_XFER_ISOC != qh->type) {
1487 			DBG(6, "RX end %d NAK timeout\n", epnum);
1488 
1489 			/* NOTE: NAKing is *NOT* an error, so we want to
1490 			 * continue.  Except ... if there's a request for
1491 			 * another QH, use that instead of starving it.
1492 			 *
1493 			 * Devices like Ethernet and serial adapters keep
1494 			 * reads posted at all times, which will starve
1495 			 * other devices without this logic.
1496 			 */
1497 			if (usb_pipebulk(urb->pipe)
1498 					&& qh->mux == 1
1499 					&& !list_is_singular(&musb->in_bulk)) {
1500 				musb_bulk_rx_nak_timeout(musb, hw_ep);
1501 				return;
1502 			}
1503 			musb_ep_select(mbase, epnum);
1504 			rx_csr |= MUSB_RXCSR_H_WZC_BITS;
1505 			rx_csr &= ~MUSB_RXCSR_DATAERROR;
1506 			musb_writew(epio, MUSB_RXCSR, rx_csr);
1507 
1508 			goto finish;
1509 		} else {
1510 			DBG(4, "RX end %d ISO data error\n", epnum);
1511 			/* packet error reported later */
1512 			iso_err = true;
1513 		}
1514 	}
1515 
1516 	/* faults abort the transfer */
1517 	if (status) {
1518 		/* clean up dma and collect transfer count */
1519 		if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1520 			dma->status = MUSB_DMA_STATUS_CORE_ABORT;
1521 			(void) musb->dma_controller->channel_abort(dma);
1522 			xfer_len = dma->actual_len;
1523 		}
1524 		musb_h_flush_rxfifo(hw_ep, MUSB_RXCSR_CLRDATATOG);
1525 		musb_writeb(epio, MUSB_RXINTERVAL, 0);
1526 		done = true;
1527 		goto finish;
1528 	}
1529 
1530 	if (unlikely(dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY)) {
1531 		/* SHOULD NEVER HAPPEN ... but at least DaVinci has done it */
1532 		ERR("RX%d dma busy, csr %04x\n", epnum, rx_csr);
1533 		goto finish;
1534 	}
1535 
1536 	/* thorough shutdown for now ... given more precise fault handling
1537 	 * and better queueing support, we might keep a DMA pipeline going
1538 	 * while processing this irq for earlier completions.
1539 	 */
1540 
1541 	/* FIXME this is _way_ too much in-line logic for Mentor DMA */
1542 
1543 #ifndef CONFIG_USB_INVENTRA_DMA
1544 	if (rx_csr & MUSB_RXCSR_H_REQPKT)  {
1545 		/* REVISIT this happened for a while on some short reads...
1546 		 * the cleanup still needs investigation... looks bad...
1547 		 * and also duplicates dma cleanup code above ... plus,
1548 		 * shouldn't this be the "half full" double buffer case?
1549 		 */
1550 		if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1551 			dma->status = MUSB_DMA_STATUS_CORE_ABORT;
1552 			(void) musb->dma_controller->channel_abort(dma);
1553 			xfer_len = dma->actual_len;
1554 			done = true;
1555 		}
1556 
1557 		DBG(2, "RXCSR%d %04x, reqpkt, len %zu%s\n", epnum, rx_csr,
1558 				xfer_len, dma ? ", dma" : "");
1559 		rx_csr &= ~MUSB_RXCSR_H_REQPKT;
1560 
1561 		musb_ep_select(mbase, epnum);
1562 		musb_writew(epio, MUSB_RXCSR,
1563 				MUSB_RXCSR_H_WZC_BITS | rx_csr);
1564 	}
1565 #endif
1566 	if (dma && (rx_csr & MUSB_RXCSR_DMAENAB)) {
1567 		xfer_len = dma->actual_len;
1568 
1569 		val &= ~(MUSB_RXCSR_DMAENAB
1570 			| MUSB_RXCSR_H_AUTOREQ
1571 			| MUSB_RXCSR_AUTOCLEAR
1572 			| MUSB_RXCSR_RXPKTRDY);
1573 		musb_writew(hw_ep->regs, MUSB_RXCSR, val);
1574 
1575 #ifdef CONFIG_USB_INVENTRA_DMA
1576 		if (usb_pipeisoc(pipe)) {
1577 			struct usb_iso_packet_descriptor *d;
1578 
1579 			d = urb->iso_frame_desc + qh->iso_idx;
1580 			d->actual_length = xfer_len;
1581 
1582 			/* even if there was an error, we did the dma
1583 			 * for iso_frame_desc->length
1584 			 */
1585 			if (d->status != EILSEQ && d->status != -EOVERFLOW)
1586 				d->status = 0;
1587 
1588 			if (++qh->iso_idx >= urb->number_of_packets)
1589 				done = true;
1590 			else
1591 				done = false;
1592 
1593 		} else  {
1594 		/* done if urb buffer is full or short packet is recd */
1595 		done = (urb->actual_length + xfer_len >=
1596 				urb->transfer_buffer_length
1597 			|| dma->actual_len < qh->maxpacket);
1598 		}
1599 
1600 		/* send IN token for next packet, without AUTOREQ */
1601 		if (!done) {
1602 			val |= MUSB_RXCSR_H_REQPKT;
1603 			musb_writew(epio, MUSB_RXCSR,
1604 				MUSB_RXCSR_H_WZC_BITS | val);
1605 		}
1606 
1607 		DBG(4, "ep %d dma %s, rxcsr %04x, rxcount %d\n", epnum,
1608 			done ? "off" : "reset",
1609 			musb_readw(epio, MUSB_RXCSR),
1610 			musb_readw(epio, MUSB_RXCOUNT));
1611 #else
1612 		done = true;
1613 #endif
1614 	} else if (urb->status == -EINPROGRESS) {
1615 		/* if no errors, be sure a packet is ready for unloading */
1616 		if (unlikely(!(rx_csr & MUSB_RXCSR_RXPKTRDY))) {
1617 			status = -EPROTO;
1618 			ERR("Rx interrupt with no errors or packet!\n");
1619 
1620 			/* FIXME this is another "SHOULD NEVER HAPPEN" */
1621 
1622 /* SCRUB (RX) */
1623 			/* do the proper sequence to abort the transfer */
1624 			musb_ep_select(mbase, epnum);
1625 			val &= ~MUSB_RXCSR_H_REQPKT;
1626 			musb_writew(epio, MUSB_RXCSR, val);
1627 			goto finish;
1628 		}
1629 
1630 		/* we are expecting IN packets */
1631 #ifdef CONFIG_USB_INVENTRA_DMA
1632 		if (dma) {
1633 			struct dma_controller	*c;
1634 			u16			rx_count;
1635 			int			ret, length;
1636 			dma_addr_t		buf;
1637 
1638 			rx_count = musb_readw(epio, MUSB_RXCOUNT);
1639 
1640 			DBG(2, "RX%d count %d, buffer 0x%x len %d/%d\n",
1641 					epnum, rx_count,
1642 					urb->transfer_dma
1643 						+ urb->actual_length,
1644 					qh->offset,
1645 					urb->transfer_buffer_length);
1646 
1647 			c = musb->dma_controller;
1648 
1649 			if (usb_pipeisoc(pipe)) {
1650 				int status = 0;
1651 				struct usb_iso_packet_descriptor *d;
1652 
1653 				d = urb->iso_frame_desc + qh->iso_idx;
1654 
1655 				if (iso_err) {
1656 					status = -EILSEQ;
1657 					urb->error_count++;
1658 				}
1659 				if (rx_count > d->length) {
1660 					if (status == 0) {
1661 						status = -EOVERFLOW;
1662 						urb->error_count++;
1663 					}
1664 					DBG(2, "** OVERFLOW %d into %d\n",\
1665 					    rx_count, d->length);
1666 
1667 					length = d->length;
1668 				} else
1669 					length = rx_count;
1670 				d->status = status;
1671 				buf = urb->transfer_dma + d->offset;
1672 			} else {
1673 				length = rx_count;
1674 				buf = urb->transfer_dma +
1675 						urb->actual_length;
1676 			}
1677 
1678 			dma->desired_mode = 0;
1679 #ifdef USE_MODE1
1680 			/* because of the issue below, mode 1 will
1681 			 * only rarely behave with correct semantics.
1682 			 */
1683 			if ((urb->transfer_flags &
1684 						URB_SHORT_NOT_OK)
1685 				&& (urb->transfer_buffer_length -
1686 						urb->actual_length)
1687 					> qh->maxpacket)
1688 				dma->desired_mode = 1;
1689 			if (rx_count < hw_ep->max_packet_sz_rx) {
1690 				length = rx_count;
1691 				dma->bDesiredMode = 0;
1692 			} else {
1693 				length = urb->transfer_buffer_length;
1694 			}
1695 #endif
1696 
1697 /* Disadvantage of using mode 1:
1698  *	It's basically usable only for mass storage class; essentially all
1699  *	other protocols also terminate transfers on short packets.
1700  *
1701  * Details:
1702  *	An extra IN token is sent at the end of the transfer (due to AUTOREQ)
1703  *	If you try to use mode 1 for (transfer_buffer_length - 512), and try
1704  *	to use the extra IN token to grab the last packet using mode 0, then
1705  *	the problem is that you cannot be sure when the device will send the
1706  *	last packet and RxPktRdy set. Sometimes the packet is recd too soon
1707  *	such that it gets lost when RxCSR is re-set at the end of the mode 1
1708  *	transfer, while sometimes it is recd just a little late so that if you
1709  *	try to configure for mode 0 soon after the mode 1 transfer is
1710  *	completed, you will find rxcount 0. Okay, so you might think why not
1711  *	wait for an interrupt when the pkt is recd. Well, you won't get any!
1712  */
1713 
1714 			val = musb_readw(epio, MUSB_RXCSR);
1715 			val &= ~MUSB_RXCSR_H_REQPKT;
1716 
1717 			if (dma->desired_mode == 0)
1718 				val &= ~MUSB_RXCSR_H_AUTOREQ;
1719 			else
1720 				val |= MUSB_RXCSR_H_AUTOREQ;
1721 			val |= MUSB_RXCSR_AUTOCLEAR | MUSB_RXCSR_DMAENAB;
1722 
1723 			musb_writew(epio, MUSB_RXCSR,
1724 				MUSB_RXCSR_H_WZC_BITS | val);
1725 
1726 			/* REVISIT if when actual_length != 0,
1727 			 * transfer_buffer_length needs to be
1728 			 * adjusted first...
1729 			 */
1730 			ret = c->channel_program(
1731 				dma, qh->maxpacket,
1732 				dma->desired_mode, buf, length);
1733 
1734 			if (!ret) {
1735 				c->channel_release(dma);
1736 				hw_ep->rx_channel = NULL;
1737 				dma = NULL;
1738 				/* REVISIT reset CSR */
1739 			}
1740 		}
1741 #endif	/* Mentor DMA */
1742 
1743 		if (!dma) {
1744 			done = musb_host_packet_rx(musb, urb,
1745 					epnum, iso_err);
1746 			DBG(6, "read %spacket\n", done ? "last " : "");
1747 		}
1748 	}
1749 
1750 finish:
1751 	urb->actual_length += xfer_len;
1752 	qh->offset += xfer_len;
1753 	if (done) {
1754 		if (urb->status == -EINPROGRESS)
1755 			urb->status = status;
1756 		musb_advance_schedule(musb, urb, hw_ep, USB_DIR_IN);
1757 	}
1758 }
1759 
1760 /* schedule nodes correspond to peripheral endpoints, like an OHCI QH.
1761  * the software schedule associates multiple such nodes with a given
1762  * host side hardware endpoint + direction; scheduling may activate
1763  * that hardware endpoint.
1764  */
1765 static int musb_schedule(
1766 	struct musb		*musb,
1767 	struct musb_qh		*qh,
1768 	int			is_in)
1769 {
1770 	int			idle;
1771 	int			best_diff;
1772 	int			best_end, epnum;
1773 	struct musb_hw_ep	*hw_ep = NULL;
1774 	struct list_head	*head = NULL;
1775 
1776 	/* use fixed hardware for control and bulk */
1777 	if (qh->type == USB_ENDPOINT_XFER_CONTROL) {
1778 		head = &musb->control;
1779 		hw_ep = musb->control_ep;
1780 		goto success;
1781 	}
1782 
1783 	/* else, periodic transfers get muxed to other endpoints */
1784 
1785 	/*
1786 	 * We know this qh hasn't been scheduled, so all we need to do
1787 	 * is choose which hardware endpoint to put it on ...
1788 	 *
1789 	 * REVISIT what we really want here is a regular schedule tree
1790 	 * like e.g. OHCI uses.
1791 	 */
1792 	best_diff = 4096;
1793 	best_end = -1;
1794 
1795 	for (epnum = 1, hw_ep = musb->endpoints + 1;
1796 			epnum < musb->nr_endpoints;
1797 			epnum++, hw_ep++) {
1798 		int	diff;
1799 
1800 		if (musb_ep_get_qh(hw_ep, is_in) != NULL)
1801 			continue;
1802 
1803 		if (hw_ep == musb->bulk_ep)
1804 			continue;
1805 
1806 		if (is_in)
1807 			diff = hw_ep->max_packet_sz_rx - qh->maxpacket;
1808 		else
1809 			diff = hw_ep->max_packet_sz_tx - qh->maxpacket;
1810 
1811 		if (diff >= 0 && best_diff > diff) {
1812 			best_diff = diff;
1813 			best_end = epnum;
1814 		}
1815 	}
1816 	/* use bulk reserved ep1 if no other ep is free */
1817 	if (best_end < 0 && qh->type == USB_ENDPOINT_XFER_BULK) {
1818 		hw_ep = musb->bulk_ep;
1819 		if (is_in)
1820 			head = &musb->in_bulk;
1821 		else
1822 			head = &musb->out_bulk;
1823 
1824 		/* Enable bulk RX NAK timeout scheme when bulk requests are
1825 		 * multiplexed.  This scheme doen't work in high speed to full
1826 		 * speed scenario as NAK interrupts are not coming from a
1827 		 * full speed device connected to a high speed device.
1828 		 * NAK timeout interval is 8 (128 uframe or 16ms) for HS and
1829 		 * 4 (8 frame or 8ms) for FS device.
1830 		 */
1831 		if (is_in && qh->dev)
1832 			qh->intv_reg =
1833 				(USB_SPEED_HIGH == qh->dev->speed) ? 8 : 4;
1834 		goto success;
1835 	} else if (best_end < 0) {
1836 		return -ENOSPC;
1837 	}
1838 
1839 	idle = 1;
1840 	qh->mux = 0;
1841 	hw_ep = musb->endpoints + best_end;
1842 	DBG(4, "qh %p periodic slot %d\n", qh, best_end);
1843 success:
1844 	if (head) {
1845 		idle = list_empty(head);
1846 		list_add_tail(&qh->ring, head);
1847 		qh->mux = 1;
1848 	}
1849 	qh->hw_ep = hw_ep;
1850 	qh->hep->hcpriv = qh;
1851 	if (idle)
1852 		musb_start_urb(musb, is_in, qh);
1853 	return 0;
1854 }
1855 
1856 static int musb_urb_enqueue(
1857 	struct usb_hcd			*hcd,
1858 	struct urb			*urb,
1859 	gfp_t				mem_flags)
1860 {
1861 	unsigned long			flags;
1862 	struct musb			*musb = hcd_to_musb(hcd);
1863 	struct usb_host_endpoint	*hep = urb->ep;
1864 	struct musb_qh			*qh;
1865 	struct usb_endpoint_descriptor	*epd = &hep->desc;
1866 	int				ret;
1867 	unsigned			type_reg;
1868 	unsigned			interval;
1869 
1870 	/* host role must be active */
1871 	if (!is_host_active(musb) || !musb->is_active)
1872 		return -ENODEV;
1873 
1874 	spin_lock_irqsave(&musb->lock, flags);
1875 	ret = usb_hcd_link_urb_to_ep(hcd, urb);
1876 	qh = ret ? NULL : hep->hcpriv;
1877 	if (qh)
1878 		urb->hcpriv = qh;
1879 	spin_unlock_irqrestore(&musb->lock, flags);
1880 
1881 	/* DMA mapping was already done, if needed, and this urb is on
1882 	 * hep->urb_list now ... so we're done, unless hep wasn't yet
1883 	 * scheduled onto a live qh.
1884 	 *
1885 	 * REVISIT best to keep hep->hcpriv valid until the endpoint gets
1886 	 * disabled, testing for empty qh->ring and avoiding qh setup costs
1887 	 * except for the first urb queued after a config change.
1888 	 */
1889 	if (qh || ret)
1890 		return ret;
1891 
1892 	/* Allocate and initialize qh, minimizing the work done each time
1893 	 * hw_ep gets reprogrammed, or with irqs blocked.  Then schedule it.
1894 	 *
1895 	 * REVISIT consider a dedicated qh kmem_cache, so it's harder
1896 	 * for bugs in other kernel code to break this driver...
1897 	 */
1898 	qh = kzalloc(sizeof *qh, mem_flags);
1899 	if (!qh) {
1900 		spin_lock_irqsave(&musb->lock, flags);
1901 		usb_hcd_unlink_urb_from_ep(hcd, urb);
1902 		spin_unlock_irqrestore(&musb->lock, flags);
1903 		return -ENOMEM;
1904 	}
1905 
1906 	qh->hep = hep;
1907 	qh->dev = urb->dev;
1908 	INIT_LIST_HEAD(&qh->ring);
1909 	qh->is_ready = 1;
1910 
1911 	qh->maxpacket = le16_to_cpu(epd->wMaxPacketSize);
1912 
1913 	/* no high bandwidth support yet */
1914 	if (qh->maxpacket & ~0x7ff) {
1915 		ret = -EMSGSIZE;
1916 		goto done;
1917 	}
1918 
1919 	qh->epnum = usb_endpoint_num(epd);
1920 	qh->type = usb_endpoint_type(epd);
1921 
1922 	/* NOTE: urb->dev->devnum is wrong during SET_ADDRESS */
1923 	qh->addr_reg = (u8) usb_pipedevice(urb->pipe);
1924 
1925 	/* precompute rxtype/txtype/type0 register */
1926 	type_reg = (qh->type << 4) | qh->epnum;
1927 	switch (urb->dev->speed) {
1928 	case USB_SPEED_LOW:
1929 		type_reg |= 0xc0;
1930 		break;
1931 	case USB_SPEED_FULL:
1932 		type_reg |= 0x80;
1933 		break;
1934 	default:
1935 		type_reg |= 0x40;
1936 	}
1937 	qh->type_reg = type_reg;
1938 
1939 	/* Precompute RXINTERVAL/TXINTERVAL register */
1940 	switch (qh->type) {
1941 	case USB_ENDPOINT_XFER_INT:
1942 		/*
1943 		 * Full/low speeds use the  linear encoding,
1944 		 * high speed uses the logarithmic encoding.
1945 		 */
1946 		if (urb->dev->speed <= USB_SPEED_FULL) {
1947 			interval = max_t(u8, epd->bInterval, 1);
1948 			break;
1949 		}
1950 		/* FALLTHROUGH */
1951 	case USB_ENDPOINT_XFER_ISOC:
1952 		/* ISO always uses logarithmic encoding */
1953 		interval = min_t(u8, epd->bInterval, 16);
1954 		break;
1955 	default:
1956 		/* REVISIT we actually want to use NAK limits, hinting to the
1957 		 * transfer scheduling logic to try some other qh, e.g. try
1958 		 * for 2 msec first:
1959 		 *
1960 		 * interval = (USB_SPEED_HIGH == urb->dev->speed) ? 16 : 2;
1961 		 *
1962 		 * The downside of disabling this is that transfer scheduling
1963 		 * gets VERY unfair for nonperiodic transfers; a misbehaving
1964 		 * peripheral could make that hurt.  That's perfectly normal
1965 		 * for reads from network or serial adapters ... so we have
1966 		 * partial NAKlimit support for bulk RX.
1967 		 *
1968 		 * The upside of disabling it is simpler transfer scheduling.
1969 		 */
1970 		interval = 0;
1971 	}
1972 	qh->intv_reg = interval;
1973 
1974 	/* precompute addressing for external hub/tt ports */
1975 	if (musb->is_multipoint) {
1976 		struct usb_device	*parent = urb->dev->parent;
1977 
1978 		if (parent != hcd->self.root_hub) {
1979 			qh->h_addr_reg = (u8) parent->devnum;
1980 
1981 			/* set up tt info if needed */
1982 			if (urb->dev->tt) {
1983 				qh->h_port_reg = (u8) urb->dev->ttport;
1984 				if (urb->dev->tt->hub)
1985 					qh->h_addr_reg =
1986 						(u8) urb->dev->tt->hub->devnum;
1987 				if (urb->dev->tt->multi)
1988 					qh->h_addr_reg |= 0x80;
1989 			}
1990 		}
1991 	}
1992 
1993 	/* invariant: hep->hcpriv is null OR the qh that's already scheduled.
1994 	 * until we get real dma queues (with an entry for each urb/buffer),
1995 	 * we only have work to do in the former case.
1996 	 */
1997 	spin_lock_irqsave(&musb->lock, flags);
1998 	if (hep->hcpriv) {
1999 		/* some concurrent activity submitted another urb to hep...
2000 		 * odd, rare, error prone, but legal.
2001 		 */
2002 		kfree(qh);
2003 		ret = 0;
2004 	} else
2005 		ret = musb_schedule(musb, qh,
2006 				epd->bEndpointAddress & USB_ENDPOINT_DIR_MASK);
2007 
2008 	if (ret == 0) {
2009 		urb->hcpriv = qh;
2010 		/* FIXME set urb->start_frame for iso/intr, it's tested in
2011 		 * musb_start_urb(), but otherwise only konicawc cares ...
2012 		 */
2013 	}
2014 	spin_unlock_irqrestore(&musb->lock, flags);
2015 
2016 done:
2017 	if (ret != 0) {
2018 		spin_lock_irqsave(&musb->lock, flags);
2019 		usb_hcd_unlink_urb_from_ep(hcd, urb);
2020 		spin_unlock_irqrestore(&musb->lock, flags);
2021 		kfree(qh);
2022 	}
2023 	return ret;
2024 }
2025 
2026 
2027 /*
2028  * abort a transfer that's at the head of a hardware queue.
2029  * called with controller locked, irqs blocked
2030  * that hardware queue advances to the next transfer, unless prevented
2031  */
2032 static int musb_cleanup_urb(struct urb *urb, struct musb_qh *qh)
2033 {
2034 	struct musb_hw_ep	*ep = qh->hw_ep;
2035 	void __iomem		*epio = ep->regs;
2036 	unsigned		hw_end = ep->epnum;
2037 	void __iomem		*regs = ep->musb->mregs;
2038 	int			is_in = usb_pipein(urb->pipe);
2039 	int			status = 0;
2040 	u16			csr;
2041 
2042 	musb_ep_select(regs, hw_end);
2043 
2044 	if (is_dma_capable()) {
2045 		struct dma_channel	*dma;
2046 
2047 		dma = is_in ? ep->rx_channel : ep->tx_channel;
2048 		if (dma) {
2049 			status = ep->musb->dma_controller->channel_abort(dma);
2050 			DBG(status ? 1 : 3,
2051 				"abort %cX%d DMA for urb %p --> %d\n",
2052 				is_in ? 'R' : 'T', ep->epnum,
2053 				urb, status);
2054 			urb->actual_length += dma->actual_len;
2055 		}
2056 	}
2057 
2058 	/* turn off DMA requests, discard state, stop polling ... */
2059 	if (is_in) {
2060 		/* giveback saves bulk toggle */
2061 		csr = musb_h_flush_rxfifo(ep, 0);
2062 
2063 		/* REVISIT we still get an irq; should likely clear the
2064 		 * endpoint's irq status here to avoid bogus irqs.
2065 		 * clearing that status is platform-specific...
2066 		 */
2067 	} else if (ep->epnum) {
2068 		musb_h_tx_flush_fifo(ep);
2069 		csr = musb_readw(epio, MUSB_TXCSR);
2070 		csr &= ~(MUSB_TXCSR_AUTOSET
2071 			| MUSB_TXCSR_DMAENAB
2072 			| MUSB_TXCSR_H_RXSTALL
2073 			| MUSB_TXCSR_H_NAKTIMEOUT
2074 			| MUSB_TXCSR_H_ERROR
2075 			| MUSB_TXCSR_TXPKTRDY);
2076 		musb_writew(epio, MUSB_TXCSR, csr);
2077 		/* REVISIT may need to clear FLUSHFIFO ... */
2078 		musb_writew(epio, MUSB_TXCSR, csr);
2079 		/* flush cpu writebuffer */
2080 		csr = musb_readw(epio, MUSB_TXCSR);
2081 	} else  {
2082 		musb_h_ep0_flush_fifo(ep);
2083 	}
2084 	if (status == 0)
2085 		musb_advance_schedule(ep->musb, urb, ep, is_in);
2086 	return status;
2087 }
2088 
2089 static int musb_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
2090 {
2091 	struct musb		*musb = hcd_to_musb(hcd);
2092 	struct musb_qh		*qh;
2093 	unsigned long		flags;
2094 	int			is_in  = usb_pipein(urb->pipe);
2095 	int			ret;
2096 
2097 	DBG(4, "urb=%p, dev%d ep%d%s\n", urb,
2098 			usb_pipedevice(urb->pipe),
2099 			usb_pipeendpoint(urb->pipe),
2100 			is_in ? "in" : "out");
2101 
2102 	spin_lock_irqsave(&musb->lock, flags);
2103 	ret = usb_hcd_check_unlink_urb(hcd, urb, status);
2104 	if (ret)
2105 		goto done;
2106 
2107 	qh = urb->hcpriv;
2108 	if (!qh)
2109 		goto done;
2110 
2111 	/*
2112 	 * Any URB not actively programmed into endpoint hardware can be
2113 	 * immediately given back; that's any URB not at the head of an
2114 	 * endpoint queue, unless someday we get real DMA queues.  And even
2115 	 * if it's at the head, it might not be known to the hardware...
2116 	 *
2117 	 * Otherwise abort current transfer, pending DMA, etc.; urb->status
2118 	 * has already been updated.  This is a synchronous abort; it'd be
2119 	 * OK to hold off until after some IRQ, though.
2120 	 *
2121 	 * NOTE: qh is invalid unless !list_empty(&hep->urb_list)
2122 	 */
2123 	if (!qh->is_ready
2124 			|| urb->urb_list.prev != &qh->hep->urb_list
2125 			|| musb_ep_get_qh(qh->hw_ep, is_in) != qh) {
2126 		int	ready = qh->is_ready;
2127 
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);
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			is_in = hep->desc.bEndpointAddress & USB_DIR_IN;
2152 	unsigned long		flags;
2153 	struct musb		*musb = hcd_to_musb(hcd);
2154 	struct musb_qh		*qh;
2155 	struct urb		*urb;
2156 
2157 	spin_lock_irqsave(&musb->lock, flags);
2158 
2159 	qh = hep->hcpriv;
2160 	if (qh == NULL)
2161 		goto exit;
2162 
2163 	/* NOTE: qh is invalid unless !list_empty(&hep->urb_list) */
2164 
2165 	/* Kick the first URB off the hardware, if needed */
2166 	qh->is_ready = 0;
2167 	if (musb_ep_get_qh(qh->hw_ep, is_in) == qh) {
2168 		urb = next_urb(qh);
2169 
2170 		/* make software (then hardware) stop ASAP */
2171 		if (!urb->unlinked)
2172 			urb->status = -ESHUTDOWN;
2173 
2174 		/* cleanup */
2175 		musb_cleanup_urb(urb, qh);
2176 
2177 		/* Then nuke all the others ... and advance the
2178 		 * queue on hw_ep (e.g. bulk ring) when we're done.
2179 		 */
2180 		while (!list_empty(&hep->urb_list)) {
2181 			urb = next_urb(qh);
2182 			urb->status = -ESHUTDOWN;
2183 			musb_advance_schedule(musb, urb, qh->hw_ep, is_in);
2184 		}
2185 	} else {
2186 		/* Just empty the queue; the hardware is busy with
2187 		 * other transfers, and since !qh->is_ready nothing
2188 		 * will activate any of these as it advances.
2189 		 */
2190 		while (!list_empty(&hep->urb_list))
2191 			__musb_giveback(musb, next_urb(qh), -ESHUTDOWN);
2192 
2193 		hep->hcpriv = NULL;
2194 		list_del(&qh->ring);
2195 		kfree(qh);
2196 	}
2197 exit:
2198 	spin_unlock_irqrestore(&musb->lock, flags);
2199 }
2200 
2201 static int musb_h_get_frame_number(struct usb_hcd *hcd)
2202 {
2203 	struct musb	*musb = hcd_to_musb(hcd);
2204 
2205 	return musb_readw(musb->mregs, MUSB_FRAME);
2206 }
2207 
2208 static int musb_h_start(struct usb_hcd *hcd)
2209 {
2210 	struct musb	*musb = hcd_to_musb(hcd);
2211 
2212 	/* NOTE: musb_start() is called when the hub driver turns
2213 	 * on port power, or when (OTG) peripheral starts.
2214 	 */
2215 	hcd->state = HC_STATE_RUNNING;
2216 	musb->port1_status = 0;
2217 	return 0;
2218 }
2219 
2220 static void musb_h_stop(struct usb_hcd *hcd)
2221 {
2222 	musb_stop(hcd_to_musb(hcd));
2223 	hcd->state = HC_STATE_HALT;
2224 }
2225 
2226 static int musb_bus_suspend(struct usb_hcd *hcd)
2227 {
2228 	struct musb	*musb = hcd_to_musb(hcd);
2229 
2230 	if (musb->xceiv.state == OTG_STATE_A_SUSPEND)
2231 		return 0;
2232 
2233 	if (is_host_active(musb) && musb->is_active) {
2234 		WARNING("trying to suspend as %s is_active=%i\n",
2235 			otg_state_string(musb), musb->is_active);
2236 		return -EBUSY;
2237 	} else
2238 		return 0;
2239 }
2240 
2241 static int musb_bus_resume(struct usb_hcd *hcd)
2242 {
2243 	/* resuming child port does the work */
2244 	return 0;
2245 }
2246 
2247 const struct hc_driver musb_hc_driver = {
2248 	.description		= "musb-hcd",
2249 	.product_desc		= "MUSB HDRC host driver",
2250 	.hcd_priv_size		= sizeof(struct musb),
2251 	.flags			= HCD_USB2 | HCD_MEMORY,
2252 
2253 	/* not using irq handler or reset hooks from usbcore, since
2254 	 * those must be shared with peripheral code for OTG configs
2255 	 */
2256 
2257 	.start			= musb_h_start,
2258 	.stop			= musb_h_stop,
2259 
2260 	.get_frame_number	= musb_h_get_frame_number,
2261 
2262 	.urb_enqueue		= musb_urb_enqueue,
2263 	.urb_dequeue		= musb_urb_dequeue,
2264 	.endpoint_disable	= musb_h_disable,
2265 
2266 	.hub_status_data	= musb_hub_status_data,
2267 	.hub_control		= musb_hub_control,
2268 	.bus_suspend		= musb_bus_suspend,
2269 	.bus_resume		= musb_bus_resume,
2270 	/* .start_port_reset	= NULL, */
2271 	/* .hub_irq_enable	= NULL, */
2272 };
2273