xref: /openbmc/linux/drivers/usb/musb/musb_host.c (revision 78c99ba1)
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 /*
185  * Start the URB at the front of an endpoint's queue
186  * end must be claimed from the caller.
187  *
188  * Context: controller locked, irqs blocked
189  */
190 static void
191 musb_start_urb(struct musb *musb, int is_in, struct musb_qh *qh)
192 {
193 	u16			frame;
194 	u32			len;
195 	void __iomem		*mbase =  musb->mregs;
196 	struct urb		*urb = next_urb(qh);
197 	void			*buf = urb->transfer_buffer;
198 	u32			offset = 0;
199 	struct musb_hw_ep	*hw_ep = qh->hw_ep;
200 	unsigned		pipe = urb->pipe;
201 	u8			address = usb_pipedevice(pipe);
202 	int			epnum = hw_ep->epnum;
203 
204 	/* initialize software qh state */
205 	qh->offset = 0;
206 	qh->segsize = 0;
207 
208 	/* gather right source of data */
209 	switch (qh->type) {
210 	case USB_ENDPOINT_XFER_CONTROL:
211 		/* control transfers always start with SETUP */
212 		is_in = 0;
213 		hw_ep->out_qh = qh;
214 		musb->ep0_stage = MUSB_EP0_START;
215 		buf = urb->setup_packet;
216 		len = 8;
217 		break;
218 	case USB_ENDPOINT_XFER_ISOC:
219 		qh->iso_idx = 0;
220 		qh->frame = 0;
221 		offset = urb->iso_frame_desc[0].offset;
222 		len = urb->iso_frame_desc[0].length;
223 		break;
224 	default:		/* bulk, interrupt */
225 		/* actual_length may be nonzero on retry paths */
226 		buf = urb->transfer_buffer + urb->actual_length;
227 		len = urb->transfer_buffer_length - urb->actual_length;
228 	}
229 
230 	DBG(4, "qh %p urb %p dev%d ep%d%s%s, hw_ep %d, %p/%d\n",
231 			qh, urb, address, qh->epnum,
232 			is_in ? "in" : "out",
233 			({char *s; switch (qh->type) {
234 			case USB_ENDPOINT_XFER_CONTROL:	s = ""; break;
235 			case USB_ENDPOINT_XFER_BULK:	s = "-bulk"; break;
236 			case USB_ENDPOINT_XFER_ISOC:	s = "-iso"; break;
237 			default:			s = "-intr"; break;
238 			}; s; }),
239 			epnum, buf + offset, len);
240 
241 	/* Configure endpoint */
242 	if (is_in || hw_ep->is_shared_fifo)
243 		hw_ep->in_qh = qh;
244 	else
245 		hw_ep->out_qh = qh;
246 	musb_ep_program(musb, epnum, urb, !is_in, buf, offset, len);
247 
248 	/* transmit may have more work: start it when it is time */
249 	if (is_in)
250 		return;
251 
252 	/* determine if the time is right for a periodic transfer */
253 	switch (qh->type) {
254 	case USB_ENDPOINT_XFER_ISOC:
255 	case USB_ENDPOINT_XFER_INT:
256 		DBG(3, "check whether there's still time for periodic Tx\n");
257 		frame = musb_readw(mbase, MUSB_FRAME);
258 		/* FIXME this doesn't implement that scheduling policy ...
259 		 * or handle framecounter wrapping
260 		 */
261 		if ((urb->transfer_flags & URB_ISO_ASAP)
262 				|| (frame >= urb->start_frame)) {
263 			/* REVISIT the SOF irq handler shouldn't duplicate
264 			 * this code; and we don't init urb->start_frame...
265 			 */
266 			qh->frame = 0;
267 			goto start;
268 		} else {
269 			qh->frame = urb->start_frame;
270 			/* enable SOF interrupt so we can count down */
271 			DBG(1, "SOF for %d\n", epnum);
272 #if 1 /* ifndef	CONFIG_ARCH_DAVINCI */
273 			musb_writeb(mbase, MUSB_INTRUSBE, 0xff);
274 #endif
275 		}
276 		break;
277 	default:
278 start:
279 		DBG(4, "Start TX%d %s\n", epnum,
280 			hw_ep->tx_channel ? "dma" : "pio");
281 
282 		if (!hw_ep->tx_channel)
283 			musb_h_tx_start(hw_ep);
284 		else if (is_cppi_enabled() || tusb_dma_omap())
285 			musb_h_tx_dma_start(hw_ep);
286 	}
287 }
288 
289 /* caller owns controller lock, irqs are blocked */
290 static void
291 __musb_giveback(struct musb *musb, struct urb *urb, int status)
292 __releases(musb->lock)
293 __acquires(musb->lock)
294 {
295 	DBG(({ int level; switch (status) {
296 				case 0:
297 					level = 4;
298 					break;
299 				/* common/boring faults */
300 				case -EREMOTEIO:
301 				case -ESHUTDOWN:
302 				case -ECONNRESET:
303 				case -EPIPE:
304 					level = 3;
305 					break;
306 				default:
307 					level = 2;
308 					break;
309 				}; level; }),
310 			"complete %p %pF (%d), dev%d ep%d%s, %d/%d\n",
311 			urb, urb->complete, status,
312 			usb_pipedevice(urb->pipe),
313 			usb_pipeendpoint(urb->pipe),
314 			usb_pipein(urb->pipe) ? "in" : "out",
315 			urb->actual_length, urb->transfer_buffer_length
316 			);
317 
318 	usb_hcd_unlink_urb_from_ep(musb_to_hcd(musb), urb);
319 	spin_unlock(&musb->lock);
320 	usb_hcd_giveback_urb(musb_to_hcd(musb), urb, status);
321 	spin_lock(&musb->lock);
322 }
323 
324 /* for bulk/interrupt endpoints only */
325 static inline void
326 musb_save_toggle(struct musb_hw_ep *ep, int is_in, struct urb *urb)
327 {
328 	struct usb_device	*udev = urb->dev;
329 	u16			csr;
330 	void __iomem		*epio = ep->regs;
331 	struct musb_qh		*qh;
332 
333 	/* FIXME:  the current Mentor DMA code seems to have
334 	 * problems getting toggle correct.
335 	 */
336 
337 	if (is_in || ep->is_shared_fifo)
338 		qh = ep->in_qh;
339 	else
340 		qh = ep->out_qh;
341 
342 	if (!is_in) {
343 		csr = musb_readw(epio, MUSB_TXCSR);
344 		usb_settoggle(udev, qh->epnum, 1,
345 			(csr & MUSB_TXCSR_H_DATATOGGLE)
346 				? 1 : 0);
347 	} else {
348 		csr = musb_readw(epio, MUSB_RXCSR);
349 		usb_settoggle(udev, qh->epnum, 0,
350 			(csr & MUSB_RXCSR_H_DATATOGGLE)
351 				? 1 : 0);
352 	}
353 }
354 
355 /* caller owns controller lock, irqs are blocked */
356 static struct musb_qh *
357 musb_giveback(struct musb_qh *qh, struct urb *urb, int status)
358 {
359 	struct musb_hw_ep	*ep = qh->hw_ep;
360 	struct musb		*musb = ep->musb;
361 	int			is_in = usb_pipein(urb->pipe);
362 	int			ready = qh->is_ready;
363 
364 	/* save toggle eagerly, for paranoia */
365 	switch (qh->type) {
366 	case USB_ENDPOINT_XFER_BULK:
367 	case USB_ENDPOINT_XFER_INT:
368 		musb_save_toggle(ep, is_in, urb);
369 		break;
370 	case USB_ENDPOINT_XFER_ISOC:
371 		if (status == 0 && urb->error_count)
372 			status = -EXDEV;
373 		break;
374 	}
375 
376 	qh->is_ready = 0;
377 	__musb_giveback(musb, urb, status);
378 	qh->is_ready = ready;
379 
380 	/* reclaim resources (and bandwidth) ASAP; deschedule it, and
381 	 * invalidate qh as soon as list_empty(&hep->urb_list)
382 	 */
383 	if (list_empty(&qh->hep->urb_list)) {
384 		struct list_head	*head;
385 
386 		if (is_in)
387 			ep->rx_reinit = 1;
388 		else
389 			ep->tx_reinit = 1;
390 
391 		/* clobber old pointers to this qh */
392 		if (is_in || ep->is_shared_fifo)
393 			ep->in_qh = NULL;
394 		else
395 			ep->out_qh = NULL;
396 		qh->hep->hcpriv = NULL;
397 
398 		switch (qh->type) {
399 
400 		case USB_ENDPOINT_XFER_CONTROL:
401 		case USB_ENDPOINT_XFER_BULK:
402 			/* fifo policy for these lists, except that NAKing
403 			 * should rotate a qh to the end (for fairness).
404 			 */
405 			if (qh->mux == 1) {
406 				head = qh->ring.prev;
407 				list_del(&qh->ring);
408 				kfree(qh);
409 				qh = first_qh(head);
410 				break;
411 			}
412 
413 		case USB_ENDPOINT_XFER_ISOC:
414 		case USB_ENDPOINT_XFER_INT:
415 			/* this is where periodic bandwidth should be
416 			 * de-allocated if it's tracked and allocated;
417 			 * and where we'd update the schedule tree...
418 			 */
419 			kfree(qh);
420 			qh = NULL;
421 			break;
422 		}
423 	}
424 	return qh;
425 }
426 
427 /*
428  * Advance this hardware endpoint's queue, completing the specified urb and
429  * advancing to either the next urb queued to that qh, or else invalidating
430  * that qh and advancing to the next qh scheduled after the current one.
431  *
432  * Context: caller owns controller lock, irqs are blocked
433  */
434 static void
435 musb_advance_schedule(struct musb *musb, struct urb *urb,
436 		struct musb_hw_ep *hw_ep, int is_in)
437 {
438 	struct musb_qh	*qh;
439 
440 	if (is_in || hw_ep->is_shared_fifo)
441 		qh = hw_ep->in_qh;
442 	else
443 		qh = hw_ep->out_qh;
444 
445 	if (urb->status == -EINPROGRESS)
446 		qh = musb_giveback(qh, urb, 0);
447 	else
448 		qh = musb_giveback(qh, urb, urb->status);
449 
450 	if (qh != NULL && qh->is_ready) {
451 		DBG(4, "... next ep%d %cX urb %p\n",
452 				hw_ep->epnum, is_in ? 'R' : 'T',
453 				next_urb(qh));
454 		musb_start_urb(musb, is_in, qh);
455 	}
456 }
457 
458 static u16 musb_h_flush_rxfifo(struct musb_hw_ep *hw_ep, u16 csr)
459 {
460 	/* we don't want fifo to fill itself again;
461 	 * ignore dma (various models),
462 	 * leave toggle alone (may not have been saved yet)
463 	 */
464 	csr |= MUSB_RXCSR_FLUSHFIFO | MUSB_RXCSR_RXPKTRDY;
465 	csr &= ~(MUSB_RXCSR_H_REQPKT
466 		| MUSB_RXCSR_H_AUTOREQ
467 		| MUSB_RXCSR_AUTOCLEAR);
468 
469 	/* write 2x to allow double buffering */
470 	musb_writew(hw_ep->regs, MUSB_RXCSR, csr);
471 	musb_writew(hw_ep->regs, MUSB_RXCSR, csr);
472 
473 	/* flush writebuffer */
474 	return musb_readw(hw_ep->regs, MUSB_RXCSR);
475 }
476 
477 /*
478  * PIO RX for a packet (or part of it).
479  */
480 static bool
481 musb_host_packet_rx(struct musb *musb, struct urb *urb, u8 epnum, u8 iso_err)
482 {
483 	u16			rx_count;
484 	u8			*buf;
485 	u16			csr;
486 	bool			done = false;
487 	u32			length;
488 	int			do_flush = 0;
489 	struct musb_hw_ep	*hw_ep = musb->endpoints + epnum;
490 	void __iomem		*epio = hw_ep->regs;
491 	struct musb_qh		*qh = hw_ep->in_qh;
492 	int			pipe = urb->pipe;
493 	void			*buffer = urb->transfer_buffer;
494 
495 	/* musb_ep_select(mbase, epnum); */
496 	rx_count = musb_readw(epio, MUSB_RXCOUNT);
497 	DBG(3, "RX%d count %d, buffer %p len %d/%d\n", epnum, rx_count,
498 			urb->transfer_buffer, qh->offset,
499 			urb->transfer_buffer_length);
500 
501 	/* unload FIFO */
502 	if (usb_pipeisoc(pipe)) {
503 		int					status = 0;
504 		struct usb_iso_packet_descriptor	*d;
505 
506 		if (iso_err) {
507 			status = -EILSEQ;
508 			urb->error_count++;
509 		}
510 
511 		d = urb->iso_frame_desc + qh->iso_idx;
512 		buf = buffer + d->offset;
513 		length = d->length;
514 		if (rx_count > length) {
515 			if (status == 0) {
516 				status = -EOVERFLOW;
517 				urb->error_count++;
518 			}
519 			DBG(2, "** OVERFLOW %d into %d\n", rx_count, length);
520 			do_flush = 1;
521 		} else
522 			length = rx_count;
523 		urb->actual_length += length;
524 		d->actual_length = length;
525 
526 		d->status = status;
527 
528 		/* see if we are done */
529 		done = (++qh->iso_idx >= urb->number_of_packets);
530 	} else {
531 		/* non-isoch */
532 		buf = buffer + qh->offset;
533 		length = urb->transfer_buffer_length - qh->offset;
534 		if (rx_count > length) {
535 			if (urb->status == -EINPROGRESS)
536 				urb->status = -EOVERFLOW;
537 			DBG(2, "** OVERFLOW %d into %d\n", rx_count, length);
538 			do_flush = 1;
539 		} else
540 			length = rx_count;
541 		urb->actual_length += length;
542 		qh->offset += length;
543 
544 		/* see if we are done */
545 		done = (urb->actual_length == urb->transfer_buffer_length)
546 			|| (rx_count < qh->maxpacket)
547 			|| (urb->status != -EINPROGRESS);
548 		if (done
549 				&& (urb->status == -EINPROGRESS)
550 				&& (urb->transfer_flags & URB_SHORT_NOT_OK)
551 				&& (urb->actual_length
552 					< urb->transfer_buffer_length))
553 			urb->status = -EREMOTEIO;
554 	}
555 
556 	musb_read_fifo(hw_ep, length, buf);
557 
558 	csr = musb_readw(epio, MUSB_RXCSR);
559 	csr |= MUSB_RXCSR_H_WZC_BITS;
560 	if (unlikely(do_flush))
561 		musb_h_flush_rxfifo(hw_ep, csr);
562 	else {
563 		/* REVISIT this assumes AUTOCLEAR is never set */
564 		csr &= ~(MUSB_RXCSR_RXPKTRDY | MUSB_RXCSR_H_REQPKT);
565 		if (!done)
566 			csr |= MUSB_RXCSR_H_REQPKT;
567 		musb_writew(epio, MUSB_RXCSR, csr);
568 	}
569 
570 	return done;
571 }
572 
573 /* we don't always need to reinit a given side of an endpoint...
574  * when we do, use tx/rx reinit routine and then construct a new CSR
575  * to address data toggle, NYET, and DMA or PIO.
576  *
577  * it's possible that driver bugs (especially for DMA) or aborting a
578  * transfer might have left the endpoint busier than it should be.
579  * the busy/not-empty tests are basically paranoia.
580  */
581 static void
582 musb_rx_reinit(struct musb *musb, struct musb_qh *qh, struct musb_hw_ep *ep)
583 {
584 	u16	csr;
585 
586 	/* NOTE:  we know the "rx" fifo reinit never triggers for ep0.
587 	 * That always uses tx_reinit since ep0 repurposes TX register
588 	 * offsets; the initial SETUP packet is also a kind of OUT.
589 	 */
590 
591 	/* if programmed for Tx, put it in RX mode */
592 	if (ep->is_shared_fifo) {
593 		csr = musb_readw(ep->regs, MUSB_TXCSR);
594 		if (csr & MUSB_TXCSR_MODE) {
595 			musb_h_tx_flush_fifo(ep);
596 			csr = musb_readw(ep->regs, MUSB_TXCSR);
597 			musb_writew(ep->regs, MUSB_TXCSR,
598 				    csr | MUSB_TXCSR_FRCDATATOG);
599 		}
600 
601 		/*
602 		 * Clear the MODE bit (and everything else) to enable Rx.
603 		 * NOTE: we mustn't clear the DMAMODE bit before DMAENAB.
604 		 */
605 		if (csr & MUSB_TXCSR_DMAMODE)
606 			musb_writew(ep->regs, MUSB_TXCSR, MUSB_TXCSR_DMAMODE);
607 		musb_writew(ep->regs, MUSB_TXCSR, 0);
608 
609 	/* scrub all previous state, clearing toggle */
610 	} else {
611 		csr = musb_readw(ep->regs, MUSB_RXCSR);
612 		if (csr & MUSB_RXCSR_RXPKTRDY)
613 			WARNING("rx%d, packet/%d ready?\n", ep->epnum,
614 				musb_readw(ep->regs, MUSB_RXCOUNT));
615 
616 		musb_h_flush_rxfifo(ep, MUSB_RXCSR_CLRDATATOG);
617 	}
618 
619 	/* target addr and (for multipoint) hub addr/port */
620 	if (musb->is_multipoint) {
621 		musb_write_rxfunaddr(ep->target_regs, qh->addr_reg);
622 		musb_write_rxhubaddr(ep->target_regs, qh->h_addr_reg);
623 		musb_write_rxhubport(ep->target_regs, qh->h_port_reg);
624 
625 	} else
626 		musb_writeb(musb->mregs, MUSB_FADDR, qh->addr_reg);
627 
628 	/* protocol/endpoint, interval/NAKlimit, i/o size */
629 	musb_writeb(ep->regs, MUSB_RXTYPE, qh->type_reg);
630 	musb_writeb(ep->regs, MUSB_RXINTERVAL, qh->intv_reg);
631 	/* NOTE: bulk combining rewrites high bits of maxpacket */
632 	musb_writew(ep->regs, MUSB_RXMAXP, qh->maxpacket);
633 
634 	ep->rx_reinit = 0;
635 }
636 
637 static bool musb_tx_dma_program(struct dma_controller *dma,
638 		struct musb_hw_ep *hw_ep, struct musb_qh *qh,
639 		struct urb *urb, u32 offset, u32 length)
640 {
641 	struct dma_channel	*channel = hw_ep->tx_channel;
642 	void __iomem		*epio = hw_ep->regs;
643 	u16			pkt_size = qh->maxpacket;
644 	u16			csr;
645 	u8			mode;
646 
647 #ifdef	CONFIG_USB_INVENTRA_DMA
648 	if (length > channel->max_len)
649 		length = channel->max_len;
650 
651 	csr = musb_readw(epio, MUSB_TXCSR);
652 	if (length > pkt_size) {
653 		mode = 1;
654 		csr |= MUSB_TXCSR_AUTOSET
655 			| MUSB_TXCSR_DMAMODE
656 			| MUSB_TXCSR_DMAENAB;
657 	} else {
658 		mode = 0;
659 		csr &= ~(MUSB_TXCSR_AUTOSET | MUSB_TXCSR_DMAMODE);
660 		csr |= MUSB_TXCSR_DMAENAB; /* against programmer's guide */
661 	}
662 	channel->desired_mode = mode;
663 	musb_writew(epio, MUSB_TXCSR, csr);
664 #else
665 	if (!is_cppi_enabled() && !tusb_dma_omap())
666 		return false;
667 
668 	channel->actual_len = 0;
669 
670 	/*
671 	 * TX uses "RNDIS" mode automatically but needs help
672 	 * to identify the zero-length-final-packet case.
673 	 */
674 	mode = (urb->transfer_flags & URB_ZERO_PACKET) ? 1 : 0;
675 #endif
676 
677 	qh->segsize = length;
678 
679 	if (!dma->channel_program(channel, pkt_size, mode,
680 			urb->transfer_dma + offset, length)) {
681 		dma->channel_release(channel);
682 		hw_ep->tx_channel = NULL;
683 
684 		csr = musb_readw(epio, MUSB_TXCSR);
685 		csr &= ~(MUSB_TXCSR_AUTOSET | MUSB_TXCSR_DMAENAB);
686 		musb_writew(epio, MUSB_TXCSR, csr | MUSB_TXCSR_H_WZC_BITS);
687 		return false;
688 	}
689 	return true;
690 }
691 
692 /*
693  * Program an HDRC endpoint as per the given URB
694  * Context: irqs blocked, controller lock held
695  */
696 static void musb_ep_program(struct musb *musb, u8 epnum,
697 			struct urb *urb, int is_out,
698 			u8 *buf, u32 offset, u32 len)
699 {
700 	struct dma_controller	*dma_controller;
701 	struct dma_channel	*dma_channel;
702 	u8			dma_ok;
703 	void __iomem		*mbase = musb->mregs;
704 	struct musb_hw_ep	*hw_ep = musb->endpoints + epnum;
705 	void __iomem		*epio = hw_ep->regs;
706 	struct musb_qh		*qh;
707 	u16			packet_sz;
708 
709 	if (!is_out || hw_ep->is_shared_fifo)
710 		qh = hw_ep->in_qh;
711 	else
712 		qh = hw_ep->out_qh;
713 
714 	packet_sz = qh->maxpacket;
715 
716 	DBG(3, "%s hw%d urb %p spd%d dev%d ep%d%s "
717 				"h_addr%02x h_port%02x bytes %d\n",
718 			is_out ? "-->" : "<--",
719 			epnum, urb, urb->dev->speed,
720 			qh->addr_reg, qh->epnum, is_out ? "out" : "in",
721 			qh->h_addr_reg, qh->h_port_reg,
722 			len);
723 
724 	musb_ep_select(mbase, epnum);
725 
726 	/* candidate for DMA? */
727 	dma_controller = musb->dma_controller;
728 	if (is_dma_capable() && epnum && dma_controller) {
729 		dma_channel = is_out ? hw_ep->tx_channel : hw_ep->rx_channel;
730 		if (!dma_channel) {
731 			dma_channel = dma_controller->channel_alloc(
732 					dma_controller, hw_ep, is_out);
733 			if (is_out)
734 				hw_ep->tx_channel = dma_channel;
735 			else
736 				hw_ep->rx_channel = dma_channel;
737 		}
738 	} else
739 		dma_channel = NULL;
740 
741 	/* make sure we clear DMAEnab, autoSet bits from previous run */
742 
743 	/* OUT/transmit/EP0 or IN/receive? */
744 	if (is_out) {
745 		u16	csr;
746 		u16	int_txe;
747 		u16	load_count;
748 
749 		csr = musb_readw(epio, MUSB_TXCSR);
750 
751 		/* disable interrupt in case we flush */
752 		int_txe = musb_readw(mbase, MUSB_INTRTXE);
753 		musb_writew(mbase, MUSB_INTRTXE, int_txe & ~(1 << epnum));
754 
755 		/* general endpoint setup */
756 		if (epnum) {
757 			/* flush all old state, set default */
758 			musb_h_tx_flush_fifo(hw_ep);
759 
760 			/*
761 			 * We must not clear the DMAMODE bit before or in
762 			 * the same cycle with the DMAENAB bit, so we clear
763 			 * the latter first...
764 			 */
765 			csr &= ~(MUSB_TXCSR_H_NAKTIMEOUT
766 					| MUSB_TXCSR_AUTOSET
767 					| MUSB_TXCSR_DMAENAB
768 					| MUSB_TXCSR_FRCDATATOG
769 					| MUSB_TXCSR_H_RXSTALL
770 					| MUSB_TXCSR_H_ERROR
771 					| MUSB_TXCSR_TXPKTRDY
772 					);
773 			csr |= MUSB_TXCSR_MODE;
774 
775 			if (usb_gettoggle(urb->dev, qh->epnum, 1))
776 				csr |= MUSB_TXCSR_H_WR_DATATOGGLE
777 					| MUSB_TXCSR_H_DATATOGGLE;
778 			else
779 				csr |= MUSB_TXCSR_CLRDATATOG;
780 
781 			musb_writew(epio, MUSB_TXCSR, csr);
782 			/* REVISIT may need to clear FLUSHFIFO ... */
783 			csr &= ~MUSB_TXCSR_DMAMODE;
784 			musb_writew(epio, MUSB_TXCSR, csr);
785 			csr = musb_readw(epio, MUSB_TXCSR);
786 		} else {
787 			/* endpoint 0: just flush */
788 			musb_h_ep0_flush_fifo(hw_ep);
789 		}
790 
791 		/* target addr and (for multipoint) hub addr/port */
792 		if (musb->is_multipoint) {
793 			musb_write_txfunaddr(mbase, epnum, qh->addr_reg);
794 			musb_write_txhubaddr(mbase, epnum, qh->h_addr_reg);
795 			musb_write_txhubport(mbase, epnum, qh->h_port_reg);
796 /* FIXME if !epnum, do the same for RX ... */
797 		} else
798 			musb_writeb(mbase, MUSB_FADDR, qh->addr_reg);
799 
800 		/* protocol/endpoint/interval/NAKlimit */
801 		if (epnum) {
802 			musb_writeb(epio, MUSB_TXTYPE, qh->type_reg);
803 			if (can_bulk_split(musb, qh->type))
804 				musb_writew(epio, MUSB_TXMAXP,
805 					packet_sz
806 					| ((hw_ep->max_packet_sz_tx /
807 						packet_sz) - 1) << 11);
808 			else
809 				musb_writew(epio, MUSB_TXMAXP,
810 					packet_sz);
811 			musb_writeb(epio, MUSB_TXINTERVAL, qh->intv_reg);
812 		} else {
813 			musb_writeb(epio, MUSB_NAKLIMIT0, qh->intv_reg);
814 			if (musb->is_multipoint)
815 				musb_writeb(epio, MUSB_TYPE0,
816 						qh->type_reg);
817 		}
818 
819 		if (can_bulk_split(musb, qh->type))
820 			load_count = min((u32) hw_ep->max_packet_sz_tx,
821 						len);
822 		else
823 			load_count = min((u32) packet_sz, len);
824 
825 		if (dma_channel && musb_tx_dma_program(dma_controller,
826 					hw_ep, qh, urb, offset, len))
827 			load_count = 0;
828 
829 		if (load_count) {
830 			/* PIO to load FIFO */
831 			qh->segsize = load_count;
832 			musb_write_fifo(hw_ep, load_count, buf);
833 		}
834 
835 		/* re-enable interrupt */
836 		musb_writew(mbase, MUSB_INTRTXE, int_txe);
837 
838 	/* IN/receive */
839 	} else {
840 		u16	csr;
841 
842 		if (hw_ep->rx_reinit) {
843 			musb_rx_reinit(musb, qh, hw_ep);
844 
845 			/* init new state: toggle and NYET, maybe DMA later */
846 			if (usb_gettoggle(urb->dev, qh->epnum, 0))
847 				csr = MUSB_RXCSR_H_WR_DATATOGGLE
848 					| MUSB_RXCSR_H_DATATOGGLE;
849 			else
850 				csr = 0;
851 			if (qh->type == USB_ENDPOINT_XFER_INT)
852 				csr |= MUSB_RXCSR_DISNYET;
853 
854 		} else {
855 			csr = musb_readw(hw_ep->regs, MUSB_RXCSR);
856 
857 			if (csr & (MUSB_RXCSR_RXPKTRDY
858 					| MUSB_RXCSR_DMAENAB
859 					| MUSB_RXCSR_H_REQPKT))
860 				ERR("broken !rx_reinit, ep%d csr %04x\n",
861 						hw_ep->epnum, csr);
862 
863 			/* scrub any stale state, leaving toggle alone */
864 			csr &= MUSB_RXCSR_DISNYET;
865 		}
866 
867 		/* kick things off */
868 
869 		if ((is_cppi_enabled() || tusb_dma_omap()) && dma_channel) {
870 			/* candidate for DMA */
871 			if (dma_channel) {
872 				dma_channel->actual_len = 0L;
873 				qh->segsize = len;
874 
875 				/* AUTOREQ is in a DMA register */
876 				musb_writew(hw_ep->regs, MUSB_RXCSR, csr);
877 				csr = musb_readw(hw_ep->regs,
878 						MUSB_RXCSR);
879 
880 				/* unless caller treats short rx transfers as
881 				 * errors, we dare not queue multiple transfers.
882 				 */
883 				dma_ok = dma_controller->channel_program(
884 						dma_channel, packet_sz,
885 						!(urb->transfer_flags
886 							& URB_SHORT_NOT_OK),
887 						urb->transfer_dma + offset,
888 						qh->segsize);
889 				if (!dma_ok) {
890 					dma_controller->channel_release(
891 							dma_channel);
892 					hw_ep->rx_channel = NULL;
893 					dma_channel = NULL;
894 				} else
895 					csr |= MUSB_RXCSR_DMAENAB;
896 			}
897 		}
898 
899 		csr |= MUSB_RXCSR_H_REQPKT;
900 		DBG(7, "RXCSR%d := %04x\n", epnum, csr);
901 		musb_writew(hw_ep->regs, MUSB_RXCSR, csr);
902 		csr = musb_readw(hw_ep->regs, MUSB_RXCSR);
903 	}
904 }
905 
906 
907 /*
908  * Service the default endpoint (ep0) as host.
909  * Return true until it's time to start the status stage.
910  */
911 static bool musb_h_ep0_continue(struct musb *musb, u16 len, struct urb *urb)
912 {
913 	bool			 more = false;
914 	u8			*fifo_dest = NULL;
915 	u16			fifo_count = 0;
916 	struct musb_hw_ep	*hw_ep = musb->control_ep;
917 	struct musb_qh		*qh = hw_ep->in_qh;
918 	struct usb_ctrlrequest	*request;
919 
920 	switch (musb->ep0_stage) {
921 	case MUSB_EP0_IN:
922 		fifo_dest = urb->transfer_buffer + urb->actual_length;
923 		fifo_count = min_t(size_t, len, urb->transfer_buffer_length -
924 				   urb->actual_length);
925 		if (fifo_count < len)
926 			urb->status = -EOVERFLOW;
927 
928 		musb_read_fifo(hw_ep, fifo_count, fifo_dest);
929 
930 		urb->actual_length += fifo_count;
931 		if (len < qh->maxpacket) {
932 			/* always terminate on short read; it's
933 			 * rarely reported as an error.
934 			 */
935 		} else if (urb->actual_length <
936 				urb->transfer_buffer_length)
937 			more = true;
938 		break;
939 	case MUSB_EP0_START:
940 		request = (struct usb_ctrlrequest *) urb->setup_packet;
941 
942 		if (!request->wLength) {
943 			DBG(4, "start no-DATA\n");
944 			break;
945 		} else if (request->bRequestType & USB_DIR_IN) {
946 			DBG(4, "start IN-DATA\n");
947 			musb->ep0_stage = MUSB_EP0_IN;
948 			more = true;
949 			break;
950 		} else {
951 			DBG(4, "start OUT-DATA\n");
952 			musb->ep0_stage = MUSB_EP0_OUT;
953 			more = true;
954 		}
955 		/* FALLTHROUGH */
956 	case MUSB_EP0_OUT:
957 		fifo_count = min_t(size_t, qh->maxpacket,
958 				   urb->transfer_buffer_length -
959 				   urb->actual_length);
960 		if (fifo_count) {
961 			fifo_dest = (u8 *) (urb->transfer_buffer
962 					+ urb->actual_length);
963 			DBG(3, "Sending %d byte%s to ep0 fifo %p\n",
964 					fifo_count,
965 					(fifo_count == 1) ? "" : "s",
966 					fifo_dest);
967 			musb_write_fifo(hw_ep, fifo_count, fifo_dest);
968 
969 			urb->actual_length += fifo_count;
970 			more = true;
971 		}
972 		break;
973 	default:
974 		ERR("bogus ep0 stage %d\n", musb->ep0_stage);
975 		break;
976 	}
977 
978 	return more;
979 }
980 
981 /*
982  * Handle default endpoint interrupt as host. Only called in IRQ time
983  * from musb_interrupt().
984  *
985  * called with controller irqlocked
986  */
987 irqreturn_t musb_h_ep0_irq(struct musb *musb)
988 {
989 	struct urb		*urb;
990 	u16			csr, len;
991 	int			status = 0;
992 	void __iomem		*mbase = musb->mregs;
993 	struct musb_hw_ep	*hw_ep = musb->control_ep;
994 	void __iomem		*epio = hw_ep->regs;
995 	struct musb_qh		*qh = hw_ep->in_qh;
996 	bool			complete = false;
997 	irqreturn_t		retval = IRQ_NONE;
998 
999 	/* ep0 only has one queue, "in" */
1000 	urb = next_urb(qh);
1001 
1002 	musb_ep_select(mbase, 0);
1003 	csr = musb_readw(epio, MUSB_CSR0);
1004 	len = (csr & MUSB_CSR0_RXPKTRDY)
1005 			? musb_readb(epio, MUSB_COUNT0)
1006 			: 0;
1007 
1008 	DBG(4, "<== csr0 %04x, qh %p, count %d, urb %p, stage %d\n",
1009 		csr, qh, len, urb, musb->ep0_stage);
1010 
1011 	/* if we just did status stage, we are done */
1012 	if (MUSB_EP0_STATUS == musb->ep0_stage) {
1013 		retval = IRQ_HANDLED;
1014 		complete = true;
1015 	}
1016 
1017 	/* prepare status */
1018 	if (csr & MUSB_CSR0_H_RXSTALL) {
1019 		DBG(6, "STALLING ENDPOINT\n");
1020 		status = -EPIPE;
1021 
1022 	} else if (csr & MUSB_CSR0_H_ERROR) {
1023 		DBG(2, "no response, csr0 %04x\n", csr);
1024 		status = -EPROTO;
1025 
1026 	} else if (csr & MUSB_CSR0_H_NAKTIMEOUT) {
1027 		DBG(2, "control NAK timeout\n");
1028 
1029 		/* NOTE:  this code path would be a good place to PAUSE a
1030 		 * control transfer, if another one is queued, so that
1031 		 * ep0 is more likely to stay busy.  That's already done
1032 		 * for bulk RX transfers.
1033 		 *
1034 		 * if (qh->ring.next != &musb->control), then
1035 		 * we have a candidate... NAKing is *NOT* an error
1036 		 */
1037 		musb_writew(epio, MUSB_CSR0, 0);
1038 		retval = IRQ_HANDLED;
1039 	}
1040 
1041 	if (status) {
1042 		DBG(6, "aborting\n");
1043 		retval = IRQ_HANDLED;
1044 		if (urb)
1045 			urb->status = status;
1046 		complete = true;
1047 
1048 		/* use the proper sequence to abort the transfer */
1049 		if (csr & MUSB_CSR0_H_REQPKT) {
1050 			csr &= ~MUSB_CSR0_H_REQPKT;
1051 			musb_writew(epio, MUSB_CSR0, csr);
1052 			csr &= ~MUSB_CSR0_H_NAKTIMEOUT;
1053 			musb_writew(epio, MUSB_CSR0, csr);
1054 		} else {
1055 			musb_h_ep0_flush_fifo(hw_ep);
1056 		}
1057 
1058 		musb_writeb(epio, MUSB_NAKLIMIT0, 0);
1059 
1060 		/* clear it */
1061 		musb_writew(epio, MUSB_CSR0, 0);
1062 	}
1063 
1064 	if (unlikely(!urb)) {
1065 		/* stop endpoint since we have no place for its data, this
1066 		 * SHOULD NEVER HAPPEN! */
1067 		ERR("no URB for end 0\n");
1068 
1069 		musb_h_ep0_flush_fifo(hw_ep);
1070 		goto done;
1071 	}
1072 
1073 	if (!complete) {
1074 		/* call common logic and prepare response */
1075 		if (musb_h_ep0_continue(musb, len, urb)) {
1076 			/* more packets required */
1077 			csr = (MUSB_EP0_IN == musb->ep0_stage)
1078 				?  MUSB_CSR0_H_REQPKT : MUSB_CSR0_TXPKTRDY;
1079 		} else {
1080 			/* data transfer complete; perform status phase */
1081 			if (usb_pipeout(urb->pipe)
1082 					|| !urb->transfer_buffer_length)
1083 				csr = MUSB_CSR0_H_STATUSPKT
1084 					| MUSB_CSR0_H_REQPKT;
1085 			else
1086 				csr = MUSB_CSR0_H_STATUSPKT
1087 					| MUSB_CSR0_TXPKTRDY;
1088 
1089 			/* flag status stage */
1090 			musb->ep0_stage = MUSB_EP0_STATUS;
1091 
1092 			DBG(5, "ep0 STATUS, csr %04x\n", csr);
1093 
1094 		}
1095 		musb_writew(epio, MUSB_CSR0, csr);
1096 		retval = IRQ_HANDLED;
1097 	} else
1098 		musb->ep0_stage = MUSB_EP0_IDLE;
1099 
1100 	/* call completion handler if done */
1101 	if (complete)
1102 		musb_advance_schedule(musb, urb, hw_ep, 1);
1103 done:
1104 	return retval;
1105 }
1106 
1107 
1108 #ifdef CONFIG_USB_INVENTRA_DMA
1109 
1110 /* Host side TX (OUT) using Mentor DMA works as follows:
1111 	submit_urb ->
1112 		- if queue was empty, Program Endpoint
1113 		- ... which starts DMA to fifo in mode 1 or 0
1114 
1115 	DMA Isr (transfer complete) -> TxAvail()
1116 		- Stop DMA (~DmaEnab)	(<--- Alert ... currently happens
1117 					only in musb_cleanup_urb)
1118 		- TxPktRdy has to be set in mode 0 or for
1119 			short packets in mode 1.
1120 */
1121 
1122 #endif
1123 
1124 /* Service a Tx-Available or dma completion irq for the endpoint */
1125 void musb_host_tx(struct musb *musb, u8 epnum)
1126 {
1127 	int			pipe;
1128 	bool			done = false;
1129 	u16			tx_csr;
1130 	size_t			length = 0;
1131 	size_t			offset = 0;
1132 	struct urb		*urb;
1133 	struct musb_hw_ep	*hw_ep = musb->endpoints + epnum;
1134 	void __iomem		*epio = hw_ep->regs;
1135 	struct musb_qh		*qh = hw_ep->is_shared_fifo ? hw_ep->in_qh
1136 							    : hw_ep->out_qh;
1137 	u32			status = 0;
1138 	void __iomem		*mbase = musb->mregs;
1139 	struct dma_channel	*dma;
1140 
1141 	urb = next_urb(qh);
1142 
1143 	musb_ep_select(mbase, epnum);
1144 	tx_csr = musb_readw(epio, MUSB_TXCSR);
1145 
1146 	/* with CPPI, DMA sometimes triggers "extra" irqs */
1147 	if (!urb) {
1148 		DBG(4, "extra TX%d ready, csr %04x\n", epnum, tx_csr);
1149 		return;
1150 	}
1151 
1152 	pipe = urb->pipe;
1153 	dma = is_dma_capable() ? hw_ep->tx_channel : NULL;
1154 	DBG(4, "OUT/TX%d end, csr %04x%s\n", epnum, tx_csr,
1155 			dma ? ", dma" : "");
1156 
1157 	/* check for errors */
1158 	if (tx_csr & MUSB_TXCSR_H_RXSTALL) {
1159 		/* dma was disabled, fifo flushed */
1160 		DBG(3, "TX end %d stall\n", epnum);
1161 
1162 		/* stall; record URB status */
1163 		status = -EPIPE;
1164 
1165 	} else if (tx_csr & MUSB_TXCSR_H_ERROR) {
1166 		/* (NON-ISO) dma was disabled, fifo flushed */
1167 		DBG(3, "TX 3strikes on ep=%d\n", epnum);
1168 
1169 		status = -ETIMEDOUT;
1170 
1171 	} else if (tx_csr & MUSB_TXCSR_H_NAKTIMEOUT) {
1172 		DBG(6, "TX end=%d device not responding\n", epnum);
1173 
1174 		/* NOTE:  this code path would be a good place to PAUSE a
1175 		 * transfer, if there's some other (nonperiodic) tx urb
1176 		 * that could use this fifo.  (dma complicates it...)
1177 		 * That's already done for bulk RX transfers.
1178 		 *
1179 		 * if (bulk && qh->ring.next != &musb->out_bulk), then
1180 		 * we have a candidate... NAKing is *NOT* an error
1181 		 */
1182 		musb_ep_select(mbase, epnum);
1183 		musb_writew(epio, MUSB_TXCSR,
1184 				MUSB_TXCSR_H_WZC_BITS
1185 				| MUSB_TXCSR_TXPKTRDY);
1186 		return;
1187 	}
1188 
1189 	if (status) {
1190 		if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1191 			dma->status = MUSB_DMA_STATUS_CORE_ABORT;
1192 			(void) musb->dma_controller->channel_abort(dma);
1193 		}
1194 
1195 		/* do the proper sequence to abort the transfer in the
1196 		 * usb core; the dma engine should already be stopped.
1197 		 */
1198 		musb_h_tx_flush_fifo(hw_ep);
1199 		tx_csr &= ~(MUSB_TXCSR_AUTOSET
1200 				| MUSB_TXCSR_DMAENAB
1201 				| MUSB_TXCSR_H_ERROR
1202 				| MUSB_TXCSR_H_RXSTALL
1203 				| MUSB_TXCSR_H_NAKTIMEOUT
1204 				);
1205 
1206 		musb_ep_select(mbase, epnum);
1207 		musb_writew(epio, MUSB_TXCSR, tx_csr);
1208 		/* REVISIT may need to clear FLUSHFIFO ... */
1209 		musb_writew(epio, MUSB_TXCSR, tx_csr);
1210 		musb_writeb(epio, MUSB_TXINTERVAL, 0);
1211 
1212 		done = true;
1213 	}
1214 
1215 	/* second cppi case */
1216 	if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1217 		DBG(4, "extra TX%d ready, csr %04x\n", epnum, tx_csr);
1218 		return;
1219 	}
1220 
1221 	if (is_dma_capable() && dma && !status) {
1222 		/*
1223 		 * DMA has completed.  But if we're using DMA mode 1 (multi
1224 		 * packet DMA), we need a terminal TXPKTRDY interrupt before
1225 		 * we can consider this transfer completed, lest we trash
1226 		 * its last packet when writing the next URB's data.  So we
1227 		 * switch back to mode 0 to get that interrupt; we'll come
1228 		 * back here once it happens.
1229 		 */
1230 		if (tx_csr & MUSB_TXCSR_DMAMODE) {
1231 			/*
1232 			 * We shouldn't clear DMAMODE with DMAENAB set; so
1233 			 * clear them in a safe order.  That should be OK
1234 			 * once TXPKTRDY has been set (and I've never seen
1235 			 * it being 0 at this moment -- DMA interrupt latency
1236 			 * is significant) but if it hasn't been then we have
1237 			 * no choice but to stop being polite and ignore the
1238 			 * programmer's guide... :-)
1239 			 *
1240 			 * Note that we must write TXCSR with TXPKTRDY cleared
1241 			 * in order not to re-trigger the packet send (this bit
1242 			 * can't be cleared by CPU), and there's another caveat:
1243 			 * TXPKTRDY may be set shortly and then cleared in the
1244 			 * double-buffered FIFO mode, so we do an extra TXCSR
1245 			 * read for debouncing...
1246 			 */
1247 			tx_csr &= musb_readw(epio, MUSB_TXCSR);
1248 			if (tx_csr & MUSB_TXCSR_TXPKTRDY) {
1249 				tx_csr &= ~(MUSB_TXCSR_DMAENAB |
1250 					    MUSB_TXCSR_TXPKTRDY);
1251 				musb_writew(epio, MUSB_TXCSR,
1252 					    tx_csr | MUSB_TXCSR_H_WZC_BITS);
1253 			}
1254 			tx_csr &= ~(MUSB_TXCSR_DMAMODE |
1255 				    MUSB_TXCSR_TXPKTRDY);
1256 			musb_writew(epio, MUSB_TXCSR,
1257 				    tx_csr | MUSB_TXCSR_H_WZC_BITS);
1258 
1259 			/*
1260 			 * There is no guarantee that we'll get an interrupt
1261 			 * after clearing DMAMODE as we might have done this
1262 			 * too late (after TXPKTRDY was cleared by controller).
1263 			 * Re-read TXCSR as we have spoiled its previous value.
1264 			 */
1265 			tx_csr = musb_readw(epio, MUSB_TXCSR);
1266 		}
1267 
1268 		/*
1269 		 * We may get here from a DMA completion or TXPKTRDY interrupt.
1270 		 * In any case, we must check the FIFO status here and bail out
1271 		 * only if the FIFO still has data -- that should prevent the
1272 		 * "missed" TXPKTRDY interrupts and deal with double-buffered
1273 		 * FIFO mode too...
1274 		 */
1275 		if (tx_csr & (MUSB_TXCSR_FIFONOTEMPTY | MUSB_TXCSR_TXPKTRDY)) {
1276 			DBG(2, "DMA complete but packet still in FIFO, "
1277 			    "CSR %04x\n", tx_csr);
1278 			return;
1279 		}
1280 	}
1281 
1282 	if (!status || dma || usb_pipeisoc(pipe)) {
1283 		if (dma)
1284 			length = dma->actual_len;
1285 		else
1286 			length = qh->segsize;
1287 		qh->offset += length;
1288 
1289 		if (usb_pipeisoc(pipe)) {
1290 			struct usb_iso_packet_descriptor	*d;
1291 
1292 			d = urb->iso_frame_desc + qh->iso_idx;
1293 			d->actual_length = length;
1294 			d->status = status;
1295 			if (++qh->iso_idx >= urb->number_of_packets) {
1296 				done = true;
1297 			} else {
1298 				d++;
1299 				offset = d->offset;
1300 				length = d->length;
1301 			}
1302 		} else if (dma) {
1303 			done = true;
1304 		} else {
1305 			/* see if we need to send more data, or ZLP */
1306 			if (qh->segsize < qh->maxpacket)
1307 				done = true;
1308 			else if (qh->offset == urb->transfer_buffer_length
1309 					&& !(urb->transfer_flags
1310 						& URB_ZERO_PACKET))
1311 				done = true;
1312 			if (!done) {
1313 				offset = qh->offset;
1314 				length = urb->transfer_buffer_length - offset;
1315 			}
1316 		}
1317 	}
1318 
1319 	/* urb->status != -EINPROGRESS means request has been faulted,
1320 	 * so we must abort this transfer after cleanup
1321 	 */
1322 	if (urb->status != -EINPROGRESS) {
1323 		done = true;
1324 		if (status == 0)
1325 			status = urb->status;
1326 	}
1327 
1328 	if (done) {
1329 		/* set status */
1330 		urb->status = status;
1331 		urb->actual_length = qh->offset;
1332 		musb_advance_schedule(musb, urb, hw_ep, USB_DIR_OUT);
1333 		return;
1334 	} else	if (usb_pipeisoc(pipe) && dma) {
1335 		if (musb_tx_dma_program(musb->dma_controller, hw_ep, qh, urb,
1336 				offset, length))
1337 			return;
1338 	} else	if (tx_csr & MUSB_TXCSR_DMAENAB) {
1339 		DBG(1, "not complete, but DMA enabled?\n");
1340 		return;
1341 	}
1342 
1343 	/*
1344 	 * PIO: start next packet in this URB.
1345 	 *
1346 	 * REVISIT: some docs say that when hw_ep->tx_double_buffered,
1347 	 * (and presumably, FIFO is not half-full) we should write *two*
1348 	 * packets before updating TXCSR; other docs disagree...
1349 	 */
1350 	if (length > qh->maxpacket)
1351 		length = qh->maxpacket;
1352 	musb_write_fifo(hw_ep, length, urb->transfer_buffer + offset);
1353 	qh->segsize = length;
1354 
1355 	musb_ep_select(mbase, epnum);
1356 	musb_writew(epio, MUSB_TXCSR,
1357 			MUSB_TXCSR_H_WZC_BITS | MUSB_TXCSR_TXPKTRDY);
1358 }
1359 
1360 
1361 #ifdef CONFIG_USB_INVENTRA_DMA
1362 
1363 /* Host side RX (IN) using Mentor DMA works as follows:
1364 	submit_urb ->
1365 		- if queue was empty, ProgramEndpoint
1366 		- first IN token is sent out (by setting ReqPkt)
1367 	LinuxIsr -> RxReady()
1368 	/\	=> first packet is received
1369 	|	- Set in mode 0 (DmaEnab, ~ReqPkt)
1370 	|		-> DMA Isr (transfer complete) -> RxReady()
1371 	|		    - Ack receive (~RxPktRdy), turn off DMA (~DmaEnab)
1372 	|		    - if urb not complete, send next IN token (ReqPkt)
1373 	|			   |		else complete urb.
1374 	|			   |
1375 	---------------------------
1376  *
1377  * Nuances of mode 1:
1378  *	For short packets, no ack (+RxPktRdy) is sent automatically
1379  *	(even if AutoClear is ON)
1380  *	For full packets, ack (~RxPktRdy) and next IN token (+ReqPkt) is sent
1381  *	automatically => major problem, as collecting the next packet becomes
1382  *	difficult. Hence mode 1 is not used.
1383  *
1384  * REVISIT
1385  *	All we care about at this driver level is that
1386  *       (a) all URBs terminate with REQPKT cleared and fifo(s) empty;
1387  *       (b) termination conditions are: short RX, or buffer full;
1388  *       (c) fault modes include
1389  *           - iff URB_SHORT_NOT_OK, short RX status is -EREMOTEIO.
1390  *             (and that endpoint's dma queue stops immediately)
1391  *           - overflow (full, PLUS more bytes in the terminal packet)
1392  *
1393  *	So for example, usb-storage sets URB_SHORT_NOT_OK, and would
1394  *	thus be a great candidate for using mode 1 ... for all but the
1395  *	last packet of one URB's transfer.
1396  */
1397 
1398 #endif
1399 
1400 /* Schedule next QH from musb->in_bulk and move the current qh to
1401  * the end; avoids starvation for other endpoints.
1402  */
1403 static void musb_bulk_rx_nak_timeout(struct musb *musb, struct musb_hw_ep *ep)
1404 {
1405 	struct dma_channel	*dma;
1406 	struct urb		*urb;
1407 	void __iomem		*mbase = musb->mregs;
1408 	void __iomem		*epio = ep->regs;
1409 	struct musb_qh		*cur_qh, *next_qh;
1410 	u16			rx_csr;
1411 
1412 	musb_ep_select(mbase, ep->epnum);
1413 	dma = is_dma_capable() ? ep->rx_channel : NULL;
1414 
1415 	/* clear nak timeout bit */
1416 	rx_csr = musb_readw(epio, MUSB_RXCSR);
1417 	rx_csr |= MUSB_RXCSR_H_WZC_BITS;
1418 	rx_csr &= ~MUSB_RXCSR_DATAERROR;
1419 	musb_writew(epio, MUSB_RXCSR, rx_csr);
1420 
1421 	cur_qh = first_qh(&musb->in_bulk);
1422 	if (cur_qh) {
1423 		urb = next_urb(cur_qh);
1424 		if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1425 			dma->status = MUSB_DMA_STATUS_CORE_ABORT;
1426 			musb->dma_controller->channel_abort(dma);
1427 			urb->actual_length += dma->actual_len;
1428 			dma->actual_len = 0L;
1429 		}
1430 		musb_save_toggle(ep, 1, urb);
1431 
1432 		/* move cur_qh to end of queue */
1433 		list_move_tail(&cur_qh->ring, &musb->in_bulk);
1434 
1435 		/* get the next qh from musb->in_bulk */
1436 		next_qh = first_qh(&musb->in_bulk);
1437 
1438 		/* set rx_reinit and schedule the next qh */
1439 		ep->rx_reinit = 1;
1440 		musb_start_urb(musb, 1, next_qh);
1441 	}
1442 }
1443 
1444 /*
1445  * Service an RX interrupt for the given IN endpoint; docs cover bulk, iso,
1446  * and high-bandwidth IN transfer cases.
1447  */
1448 void musb_host_rx(struct musb *musb, u8 epnum)
1449 {
1450 	struct urb		*urb;
1451 	struct musb_hw_ep	*hw_ep = musb->endpoints + epnum;
1452 	void __iomem		*epio = hw_ep->regs;
1453 	struct musb_qh		*qh = hw_ep->in_qh;
1454 	size_t			xfer_len;
1455 	void __iomem		*mbase = musb->mregs;
1456 	int			pipe;
1457 	u16			rx_csr, val;
1458 	bool			iso_err = false;
1459 	bool			done = false;
1460 	u32			status;
1461 	struct dma_channel	*dma;
1462 
1463 	musb_ep_select(mbase, epnum);
1464 
1465 	urb = next_urb(qh);
1466 	dma = is_dma_capable() ? hw_ep->rx_channel : NULL;
1467 	status = 0;
1468 	xfer_len = 0;
1469 
1470 	rx_csr = musb_readw(epio, MUSB_RXCSR);
1471 	val = rx_csr;
1472 
1473 	if (unlikely(!urb)) {
1474 		/* REVISIT -- THIS SHOULD NEVER HAPPEN ... but, at least
1475 		 * usbtest #11 (unlinks) triggers it regularly, sometimes
1476 		 * with fifo full.  (Only with DMA??)
1477 		 */
1478 		DBG(3, "BOGUS RX%d ready, csr %04x, count %d\n", epnum, val,
1479 			musb_readw(epio, MUSB_RXCOUNT));
1480 		musb_h_flush_rxfifo(hw_ep, MUSB_RXCSR_CLRDATATOG);
1481 		return;
1482 	}
1483 
1484 	pipe = urb->pipe;
1485 
1486 	DBG(5, "<== hw %d rxcsr %04x, urb actual %d (+dma %zu)\n",
1487 		epnum, rx_csr, urb->actual_length,
1488 		dma ? dma->actual_len : 0);
1489 
1490 	/* check for errors, concurrent stall & unlink is not really
1491 	 * handled yet! */
1492 	if (rx_csr & MUSB_RXCSR_H_RXSTALL) {
1493 		DBG(3, "RX end %d STALL\n", epnum);
1494 
1495 		/* stall; record URB status */
1496 		status = -EPIPE;
1497 
1498 	} else if (rx_csr & MUSB_RXCSR_H_ERROR) {
1499 		DBG(3, "end %d RX proto error\n", epnum);
1500 
1501 		status = -EPROTO;
1502 		musb_writeb(epio, MUSB_RXINTERVAL, 0);
1503 
1504 	} else if (rx_csr & MUSB_RXCSR_DATAERROR) {
1505 
1506 		if (USB_ENDPOINT_XFER_ISOC != qh->type) {
1507 			DBG(6, "RX end %d NAK timeout\n", epnum);
1508 
1509 			/* NOTE: NAKing is *NOT* an error, so we want to
1510 			 * continue.  Except ... if there's a request for
1511 			 * another QH, use that instead of starving it.
1512 			 *
1513 			 * Devices like Ethernet and serial adapters keep
1514 			 * reads posted at all times, which will starve
1515 			 * other devices without this logic.
1516 			 */
1517 			if (usb_pipebulk(urb->pipe)
1518 					&& qh->mux == 1
1519 					&& !list_is_singular(&musb->in_bulk)) {
1520 				musb_bulk_rx_nak_timeout(musb, hw_ep);
1521 				return;
1522 			}
1523 			musb_ep_select(mbase, epnum);
1524 			rx_csr |= MUSB_RXCSR_H_WZC_BITS;
1525 			rx_csr &= ~MUSB_RXCSR_DATAERROR;
1526 			musb_writew(epio, MUSB_RXCSR, rx_csr);
1527 
1528 			goto finish;
1529 		} else {
1530 			DBG(4, "RX end %d ISO data error\n", epnum);
1531 			/* packet error reported later */
1532 			iso_err = true;
1533 		}
1534 	}
1535 
1536 	/* faults abort the transfer */
1537 	if (status) {
1538 		/* clean up dma and collect transfer count */
1539 		if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1540 			dma->status = MUSB_DMA_STATUS_CORE_ABORT;
1541 			(void) musb->dma_controller->channel_abort(dma);
1542 			xfer_len = dma->actual_len;
1543 		}
1544 		musb_h_flush_rxfifo(hw_ep, MUSB_RXCSR_CLRDATATOG);
1545 		musb_writeb(epio, MUSB_RXINTERVAL, 0);
1546 		done = true;
1547 		goto finish;
1548 	}
1549 
1550 	if (unlikely(dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY)) {
1551 		/* SHOULD NEVER HAPPEN ... but at least DaVinci has done it */
1552 		ERR("RX%d dma busy, csr %04x\n", epnum, rx_csr);
1553 		goto finish;
1554 	}
1555 
1556 	/* thorough shutdown for now ... given more precise fault handling
1557 	 * and better queueing support, we might keep a DMA pipeline going
1558 	 * while processing this irq for earlier completions.
1559 	 */
1560 
1561 	/* FIXME this is _way_ too much in-line logic for Mentor DMA */
1562 
1563 #ifndef CONFIG_USB_INVENTRA_DMA
1564 	if (rx_csr & MUSB_RXCSR_H_REQPKT)  {
1565 		/* REVISIT this happened for a while on some short reads...
1566 		 * the cleanup still needs investigation... looks bad...
1567 		 * and also duplicates dma cleanup code above ... plus,
1568 		 * shouldn't this be the "half full" double buffer case?
1569 		 */
1570 		if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1571 			dma->status = MUSB_DMA_STATUS_CORE_ABORT;
1572 			(void) musb->dma_controller->channel_abort(dma);
1573 			xfer_len = dma->actual_len;
1574 			done = true;
1575 		}
1576 
1577 		DBG(2, "RXCSR%d %04x, reqpkt, len %zu%s\n", epnum, rx_csr,
1578 				xfer_len, dma ? ", dma" : "");
1579 		rx_csr &= ~MUSB_RXCSR_H_REQPKT;
1580 
1581 		musb_ep_select(mbase, epnum);
1582 		musb_writew(epio, MUSB_RXCSR,
1583 				MUSB_RXCSR_H_WZC_BITS | rx_csr);
1584 	}
1585 #endif
1586 	if (dma && (rx_csr & MUSB_RXCSR_DMAENAB)) {
1587 		xfer_len = dma->actual_len;
1588 
1589 		val &= ~(MUSB_RXCSR_DMAENAB
1590 			| MUSB_RXCSR_H_AUTOREQ
1591 			| MUSB_RXCSR_AUTOCLEAR
1592 			| MUSB_RXCSR_RXPKTRDY);
1593 		musb_writew(hw_ep->regs, MUSB_RXCSR, val);
1594 
1595 #ifdef CONFIG_USB_INVENTRA_DMA
1596 		if (usb_pipeisoc(pipe)) {
1597 			struct usb_iso_packet_descriptor *d;
1598 
1599 			d = urb->iso_frame_desc + qh->iso_idx;
1600 			d->actual_length = xfer_len;
1601 
1602 			/* even if there was an error, we did the dma
1603 			 * for iso_frame_desc->length
1604 			 */
1605 			if (d->status != EILSEQ && d->status != -EOVERFLOW)
1606 				d->status = 0;
1607 
1608 			if (++qh->iso_idx >= urb->number_of_packets)
1609 				done = true;
1610 			else
1611 				done = false;
1612 
1613 		} else  {
1614 		/* done if urb buffer is full or short packet is recd */
1615 		done = (urb->actual_length + xfer_len >=
1616 				urb->transfer_buffer_length
1617 			|| dma->actual_len < qh->maxpacket);
1618 		}
1619 
1620 		/* send IN token for next packet, without AUTOREQ */
1621 		if (!done) {
1622 			val |= MUSB_RXCSR_H_REQPKT;
1623 			musb_writew(epio, MUSB_RXCSR,
1624 				MUSB_RXCSR_H_WZC_BITS | val);
1625 		}
1626 
1627 		DBG(4, "ep %d dma %s, rxcsr %04x, rxcount %d\n", epnum,
1628 			done ? "off" : "reset",
1629 			musb_readw(epio, MUSB_RXCSR),
1630 			musb_readw(epio, MUSB_RXCOUNT));
1631 #else
1632 		done = true;
1633 #endif
1634 	} else if (urb->status == -EINPROGRESS) {
1635 		/* if no errors, be sure a packet is ready for unloading */
1636 		if (unlikely(!(rx_csr & MUSB_RXCSR_RXPKTRDY))) {
1637 			status = -EPROTO;
1638 			ERR("Rx interrupt with no errors or packet!\n");
1639 
1640 			/* FIXME this is another "SHOULD NEVER HAPPEN" */
1641 
1642 /* SCRUB (RX) */
1643 			/* do the proper sequence to abort the transfer */
1644 			musb_ep_select(mbase, epnum);
1645 			val &= ~MUSB_RXCSR_H_REQPKT;
1646 			musb_writew(epio, MUSB_RXCSR, val);
1647 			goto finish;
1648 		}
1649 
1650 		/* we are expecting IN packets */
1651 #ifdef CONFIG_USB_INVENTRA_DMA
1652 		if (dma) {
1653 			struct dma_controller	*c;
1654 			u16			rx_count;
1655 			int			ret, length;
1656 			dma_addr_t		buf;
1657 
1658 			rx_count = musb_readw(epio, MUSB_RXCOUNT);
1659 
1660 			DBG(2, "RX%d count %d, buffer 0x%x len %d/%d\n",
1661 					epnum, rx_count,
1662 					urb->transfer_dma
1663 						+ urb->actual_length,
1664 					qh->offset,
1665 					urb->transfer_buffer_length);
1666 
1667 			c = musb->dma_controller;
1668 
1669 			if (usb_pipeisoc(pipe)) {
1670 				int status = 0;
1671 				struct usb_iso_packet_descriptor *d;
1672 
1673 				d = urb->iso_frame_desc + qh->iso_idx;
1674 
1675 				if (iso_err) {
1676 					status = -EILSEQ;
1677 					urb->error_count++;
1678 				}
1679 				if (rx_count > d->length) {
1680 					if (status == 0) {
1681 						status = -EOVERFLOW;
1682 						urb->error_count++;
1683 					}
1684 					DBG(2, "** OVERFLOW %d into %d\n",\
1685 					    rx_count, d->length);
1686 
1687 					length = d->length;
1688 				} else
1689 					length = rx_count;
1690 				d->status = status;
1691 				buf = urb->transfer_dma + d->offset;
1692 			} else {
1693 				length = rx_count;
1694 				buf = urb->transfer_dma +
1695 						urb->actual_length;
1696 			}
1697 
1698 			dma->desired_mode = 0;
1699 #ifdef USE_MODE1
1700 			/* because of the issue below, mode 1 will
1701 			 * only rarely behave with correct semantics.
1702 			 */
1703 			if ((urb->transfer_flags &
1704 						URB_SHORT_NOT_OK)
1705 				&& (urb->transfer_buffer_length -
1706 						urb->actual_length)
1707 					> qh->maxpacket)
1708 				dma->desired_mode = 1;
1709 			if (rx_count < hw_ep->max_packet_sz_rx) {
1710 				length = rx_count;
1711 				dma->bDesiredMode = 0;
1712 			} else {
1713 				length = urb->transfer_buffer_length;
1714 			}
1715 #endif
1716 
1717 /* Disadvantage of using mode 1:
1718  *	It's basically usable only for mass storage class; essentially all
1719  *	other protocols also terminate transfers on short packets.
1720  *
1721  * Details:
1722  *	An extra IN token is sent at the end of the transfer (due to AUTOREQ)
1723  *	If you try to use mode 1 for (transfer_buffer_length - 512), and try
1724  *	to use the extra IN token to grab the last packet using mode 0, then
1725  *	the problem is that you cannot be sure when the device will send the
1726  *	last packet and RxPktRdy set. Sometimes the packet is recd too soon
1727  *	such that it gets lost when RxCSR is re-set at the end of the mode 1
1728  *	transfer, while sometimes it is recd just a little late so that if you
1729  *	try to configure for mode 0 soon after the mode 1 transfer is
1730  *	completed, you will find rxcount 0. Okay, so you might think why not
1731  *	wait for an interrupt when the pkt is recd. Well, you won't get any!
1732  */
1733 
1734 			val = musb_readw(epio, MUSB_RXCSR);
1735 			val &= ~MUSB_RXCSR_H_REQPKT;
1736 
1737 			if (dma->desired_mode == 0)
1738 				val &= ~MUSB_RXCSR_H_AUTOREQ;
1739 			else
1740 				val |= MUSB_RXCSR_H_AUTOREQ;
1741 			val |= MUSB_RXCSR_AUTOCLEAR | MUSB_RXCSR_DMAENAB;
1742 
1743 			musb_writew(epio, MUSB_RXCSR,
1744 				MUSB_RXCSR_H_WZC_BITS | val);
1745 
1746 			/* REVISIT if when actual_length != 0,
1747 			 * transfer_buffer_length needs to be
1748 			 * adjusted first...
1749 			 */
1750 			ret = c->channel_program(
1751 				dma, qh->maxpacket,
1752 				dma->desired_mode, buf, length);
1753 
1754 			if (!ret) {
1755 				c->channel_release(dma);
1756 				hw_ep->rx_channel = NULL;
1757 				dma = NULL;
1758 				/* REVISIT reset CSR */
1759 			}
1760 		}
1761 #endif	/* Mentor DMA */
1762 
1763 		if (!dma) {
1764 			done = musb_host_packet_rx(musb, urb,
1765 					epnum, iso_err);
1766 			DBG(6, "read %spacket\n", done ? "last " : "");
1767 		}
1768 	}
1769 
1770 finish:
1771 	urb->actual_length += xfer_len;
1772 	qh->offset += xfer_len;
1773 	if (done) {
1774 		if (urb->status == -EINPROGRESS)
1775 			urb->status = status;
1776 		musb_advance_schedule(musb, urb, hw_ep, USB_DIR_IN);
1777 	}
1778 }
1779 
1780 /* schedule nodes correspond to peripheral endpoints, like an OHCI QH.
1781  * the software schedule associates multiple such nodes with a given
1782  * host side hardware endpoint + direction; scheduling may activate
1783  * that hardware endpoint.
1784  */
1785 static int musb_schedule(
1786 	struct musb		*musb,
1787 	struct musb_qh		*qh,
1788 	int			is_in)
1789 {
1790 	int			idle;
1791 	int			best_diff;
1792 	int			best_end, epnum;
1793 	struct musb_hw_ep	*hw_ep = NULL;
1794 	struct list_head	*head = NULL;
1795 
1796 	/* use fixed hardware for control and bulk */
1797 	if (qh->type == USB_ENDPOINT_XFER_CONTROL) {
1798 		head = &musb->control;
1799 		hw_ep = musb->control_ep;
1800 		goto success;
1801 	}
1802 
1803 	/* else, periodic transfers get muxed to other endpoints */
1804 
1805 	/*
1806 	 * We know this qh hasn't been scheduled, so all we need to do
1807 	 * is choose which hardware endpoint to put it on ...
1808 	 *
1809 	 * REVISIT what we really want here is a regular schedule tree
1810 	 * like e.g. OHCI uses.
1811 	 */
1812 	best_diff = 4096;
1813 	best_end = -1;
1814 
1815 	for (epnum = 1, hw_ep = musb->endpoints + 1;
1816 			epnum < musb->nr_endpoints;
1817 			epnum++, hw_ep++) {
1818 		int	diff;
1819 
1820 		if (is_in || hw_ep->is_shared_fifo) {
1821 			if (hw_ep->in_qh  != NULL)
1822 				continue;
1823 		} else	if (hw_ep->out_qh != NULL)
1824 			continue;
1825 
1826 		if (hw_ep == musb->bulk_ep)
1827 			continue;
1828 
1829 		if (is_in)
1830 			diff = hw_ep->max_packet_sz_rx - qh->maxpacket;
1831 		else
1832 			diff = hw_ep->max_packet_sz_tx - qh->maxpacket;
1833 
1834 		if (diff >= 0 && best_diff > diff) {
1835 			best_diff = diff;
1836 			best_end = epnum;
1837 		}
1838 	}
1839 	/* use bulk reserved ep1 if no other ep is free */
1840 	if (best_end < 0 && qh->type == USB_ENDPOINT_XFER_BULK) {
1841 		hw_ep = musb->bulk_ep;
1842 		if (is_in)
1843 			head = &musb->in_bulk;
1844 		else
1845 			head = &musb->out_bulk;
1846 
1847 		/* Enable bulk RX NAK timeout scheme when bulk requests are
1848 		 * multiplexed.  This scheme doen't work in high speed to full
1849 		 * speed scenario as NAK interrupts are not coming from a
1850 		 * full speed device connected to a high speed device.
1851 		 * NAK timeout interval is 8 (128 uframe or 16ms) for HS and
1852 		 * 4 (8 frame or 8ms) for FS device.
1853 		 */
1854 		if (is_in && qh->dev)
1855 			qh->intv_reg =
1856 				(USB_SPEED_HIGH == qh->dev->speed) ? 8 : 4;
1857 		goto success;
1858 	} else if (best_end < 0) {
1859 		return -ENOSPC;
1860 	}
1861 
1862 	idle = 1;
1863 	qh->mux = 0;
1864 	hw_ep = musb->endpoints + best_end;
1865 	DBG(4, "qh %p periodic slot %d\n", qh, best_end);
1866 success:
1867 	if (head) {
1868 		idle = list_empty(head);
1869 		list_add_tail(&qh->ring, head);
1870 		qh->mux = 1;
1871 	}
1872 	qh->hw_ep = hw_ep;
1873 	qh->hep->hcpriv = qh;
1874 	if (idle)
1875 		musb_start_urb(musb, is_in, qh);
1876 	return 0;
1877 }
1878 
1879 static int musb_urb_enqueue(
1880 	struct usb_hcd			*hcd,
1881 	struct urb			*urb,
1882 	gfp_t				mem_flags)
1883 {
1884 	unsigned long			flags;
1885 	struct musb			*musb = hcd_to_musb(hcd);
1886 	struct usb_host_endpoint	*hep = urb->ep;
1887 	struct musb_qh			*qh;
1888 	struct usb_endpoint_descriptor	*epd = &hep->desc;
1889 	int				ret;
1890 	unsigned			type_reg;
1891 	unsigned			interval;
1892 
1893 	/* host role must be active */
1894 	if (!is_host_active(musb) || !musb->is_active)
1895 		return -ENODEV;
1896 
1897 	spin_lock_irqsave(&musb->lock, flags);
1898 	ret = usb_hcd_link_urb_to_ep(hcd, urb);
1899 	qh = ret ? NULL : hep->hcpriv;
1900 	if (qh)
1901 		urb->hcpriv = qh;
1902 	spin_unlock_irqrestore(&musb->lock, flags);
1903 
1904 	/* DMA mapping was already done, if needed, and this urb is on
1905 	 * hep->urb_list now ... so we're done, unless hep wasn't yet
1906 	 * scheduled onto a live qh.
1907 	 *
1908 	 * REVISIT best to keep hep->hcpriv valid until the endpoint gets
1909 	 * disabled, testing for empty qh->ring and avoiding qh setup costs
1910 	 * except for the first urb queued after a config change.
1911 	 */
1912 	if (qh || ret)
1913 		return ret;
1914 
1915 	/* Allocate and initialize qh, minimizing the work done each time
1916 	 * hw_ep gets reprogrammed, or with irqs blocked.  Then schedule it.
1917 	 *
1918 	 * REVISIT consider a dedicated qh kmem_cache, so it's harder
1919 	 * for bugs in other kernel code to break this driver...
1920 	 */
1921 	qh = kzalloc(sizeof *qh, mem_flags);
1922 	if (!qh) {
1923 		spin_lock_irqsave(&musb->lock, flags);
1924 		usb_hcd_unlink_urb_from_ep(hcd, urb);
1925 		spin_unlock_irqrestore(&musb->lock, flags);
1926 		return -ENOMEM;
1927 	}
1928 
1929 	qh->hep = hep;
1930 	qh->dev = urb->dev;
1931 	INIT_LIST_HEAD(&qh->ring);
1932 	qh->is_ready = 1;
1933 
1934 	qh->maxpacket = le16_to_cpu(epd->wMaxPacketSize);
1935 
1936 	/* no high bandwidth support yet */
1937 	if (qh->maxpacket & ~0x7ff) {
1938 		ret = -EMSGSIZE;
1939 		goto done;
1940 	}
1941 
1942 	qh->epnum = usb_endpoint_num(epd);
1943 	qh->type = usb_endpoint_type(epd);
1944 
1945 	/* NOTE: urb->dev->devnum is wrong during SET_ADDRESS */
1946 	qh->addr_reg = (u8) usb_pipedevice(urb->pipe);
1947 
1948 	/* precompute rxtype/txtype/type0 register */
1949 	type_reg = (qh->type << 4) | qh->epnum;
1950 	switch (urb->dev->speed) {
1951 	case USB_SPEED_LOW:
1952 		type_reg |= 0xc0;
1953 		break;
1954 	case USB_SPEED_FULL:
1955 		type_reg |= 0x80;
1956 		break;
1957 	default:
1958 		type_reg |= 0x40;
1959 	}
1960 	qh->type_reg = type_reg;
1961 
1962 	/* Precompute RXINTERVAL/TXINTERVAL register */
1963 	switch (qh->type) {
1964 	case USB_ENDPOINT_XFER_INT:
1965 		/*
1966 		 * Full/low speeds use the  linear encoding,
1967 		 * high speed uses the logarithmic encoding.
1968 		 */
1969 		if (urb->dev->speed <= USB_SPEED_FULL) {
1970 			interval = max_t(u8, epd->bInterval, 1);
1971 			break;
1972 		}
1973 		/* FALLTHROUGH */
1974 	case USB_ENDPOINT_XFER_ISOC:
1975 		/* ISO always uses logarithmic encoding */
1976 		interval = min_t(u8, epd->bInterval, 16);
1977 		break;
1978 	default:
1979 		/* REVISIT we actually want to use NAK limits, hinting to the
1980 		 * transfer scheduling logic to try some other qh, e.g. try
1981 		 * for 2 msec first:
1982 		 *
1983 		 * interval = (USB_SPEED_HIGH == urb->dev->speed) ? 16 : 2;
1984 		 *
1985 		 * The downside of disabling this is that transfer scheduling
1986 		 * gets VERY unfair for nonperiodic transfers; a misbehaving
1987 		 * peripheral could make that hurt.  That's perfectly normal
1988 		 * for reads from network or serial adapters ... so we have
1989 		 * partial NAKlimit support for bulk RX.
1990 		 *
1991 		 * The upside of disabling it is simpler transfer scheduling.
1992 		 */
1993 		interval = 0;
1994 	}
1995 	qh->intv_reg = interval;
1996 
1997 	/* precompute addressing for external hub/tt ports */
1998 	if (musb->is_multipoint) {
1999 		struct usb_device	*parent = urb->dev->parent;
2000 
2001 		if (parent != hcd->self.root_hub) {
2002 			qh->h_addr_reg = (u8) parent->devnum;
2003 
2004 			/* set up tt info if needed */
2005 			if (urb->dev->tt) {
2006 				qh->h_port_reg = (u8) urb->dev->ttport;
2007 				if (urb->dev->tt->hub)
2008 					qh->h_addr_reg =
2009 						(u8) urb->dev->tt->hub->devnum;
2010 				if (urb->dev->tt->multi)
2011 					qh->h_addr_reg |= 0x80;
2012 			}
2013 		}
2014 	}
2015 
2016 	/* invariant: hep->hcpriv is null OR the qh that's already scheduled.
2017 	 * until we get real dma queues (with an entry for each urb/buffer),
2018 	 * we only have work to do in the former case.
2019 	 */
2020 	spin_lock_irqsave(&musb->lock, flags);
2021 	if (hep->hcpriv) {
2022 		/* some concurrent activity submitted another urb to hep...
2023 		 * odd, rare, error prone, but legal.
2024 		 */
2025 		kfree(qh);
2026 		ret = 0;
2027 	} else
2028 		ret = musb_schedule(musb, qh,
2029 				epd->bEndpointAddress & USB_ENDPOINT_DIR_MASK);
2030 
2031 	if (ret == 0) {
2032 		urb->hcpriv = qh;
2033 		/* FIXME set urb->start_frame for iso/intr, it's tested in
2034 		 * musb_start_urb(), but otherwise only konicawc cares ...
2035 		 */
2036 	}
2037 	spin_unlock_irqrestore(&musb->lock, flags);
2038 
2039 done:
2040 	if (ret != 0) {
2041 		spin_lock_irqsave(&musb->lock, flags);
2042 		usb_hcd_unlink_urb_from_ep(hcd, urb);
2043 		spin_unlock_irqrestore(&musb->lock, flags);
2044 		kfree(qh);
2045 	}
2046 	return ret;
2047 }
2048 
2049 
2050 /*
2051  * abort a transfer that's at the head of a hardware queue.
2052  * called with controller locked, irqs blocked
2053  * that hardware queue advances to the next transfer, unless prevented
2054  */
2055 static int musb_cleanup_urb(struct urb *urb, struct musb_qh *qh, int is_in)
2056 {
2057 	struct musb_hw_ep	*ep = qh->hw_ep;
2058 	void __iomem		*epio = ep->regs;
2059 	unsigned		hw_end = ep->epnum;
2060 	void __iomem		*regs = ep->musb->mregs;
2061 	u16			csr;
2062 	int			status = 0;
2063 
2064 	musb_ep_select(regs, hw_end);
2065 
2066 	if (is_dma_capable()) {
2067 		struct dma_channel	*dma;
2068 
2069 		dma = is_in ? ep->rx_channel : ep->tx_channel;
2070 		if (dma) {
2071 			status = ep->musb->dma_controller->channel_abort(dma);
2072 			DBG(status ? 1 : 3,
2073 				"abort %cX%d DMA for urb %p --> %d\n",
2074 				is_in ? 'R' : 'T', ep->epnum,
2075 				urb, status);
2076 			urb->actual_length += dma->actual_len;
2077 		}
2078 	}
2079 
2080 	/* turn off DMA requests, discard state, stop polling ... */
2081 	if (is_in) {
2082 		/* giveback saves bulk toggle */
2083 		csr = musb_h_flush_rxfifo(ep, 0);
2084 
2085 		/* REVISIT we still get an irq; should likely clear the
2086 		 * endpoint's irq status here to avoid bogus irqs.
2087 		 * clearing that status is platform-specific...
2088 		 */
2089 	} else if (ep->epnum) {
2090 		musb_h_tx_flush_fifo(ep);
2091 		csr = musb_readw(epio, MUSB_TXCSR);
2092 		csr &= ~(MUSB_TXCSR_AUTOSET
2093 			| MUSB_TXCSR_DMAENAB
2094 			| MUSB_TXCSR_H_RXSTALL
2095 			| MUSB_TXCSR_H_NAKTIMEOUT
2096 			| MUSB_TXCSR_H_ERROR
2097 			| MUSB_TXCSR_TXPKTRDY);
2098 		musb_writew(epio, MUSB_TXCSR, csr);
2099 		/* REVISIT may need to clear FLUSHFIFO ... */
2100 		musb_writew(epio, MUSB_TXCSR, csr);
2101 		/* flush cpu writebuffer */
2102 		csr = musb_readw(epio, MUSB_TXCSR);
2103 	} else  {
2104 		musb_h_ep0_flush_fifo(ep);
2105 	}
2106 	if (status == 0)
2107 		musb_advance_schedule(ep->musb, urb, ep, is_in);
2108 	return status;
2109 }
2110 
2111 static int musb_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
2112 {
2113 	struct musb		*musb = hcd_to_musb(hcd);
2114 	struct musb_qh		*qh;
2115 	struct list_head	*sched;
2116 	unsigned long		flags;
2117 	int			ret;
2118 
2119 	DBG(4, "urb=%p, dev%d ep%d%s\n", urb,
2120 			usb_pipedevice(urb->pipe),
2121 			usb_pipeendpoint(urb->pipe),
2122 			usb_pipein(urb->pipe) ? "in" : "out");
2123 
2124 	spin_lock_irqsave(&musb->lock, flags);
2125 	ret = usb_hcd_check_unlink_urb(hcd, urb, status);
2126 	if (ret)
2127 		goto done;
2128 
2129 	qh = urb->hcpriv;
2130 	if (!qh)
2131 		goto done;
2132 
2133 	/* Any URB not actively programmed into endpoint hardware can be
2134 	 * immediately given back; that's any URB not at the head of an
2135 	 * endpoint queue, unless someday we get real DMA queues.  And even
2136 	 * if it's at the head, it might not be known to the hardware...
2137 	 *
2138 	 * Otherwise abort current transfer, pending dma, etc.; urb->status
2139 	 * has already been updated.  This is a synchronous abort; it'd be
2140 	 * OK to hold off until after some IRQ, though.
2141 	 */
2142 	if (!qh->is_ready || urb->urb_list.prev != &qh->hep->urb_list)
2143 		ret = -EINPROGRESS;
2144 	else {
2145 		switch (qh->type) {
2146 		case USB_ENDPOINT_XFER_CONTROL:
2147 			sched = &musb->control;
2148 			break;
2149 		case USB_ENDPOINT_XFER_BULK:
2150 			if (qh->mux == 1) {
2151 				if (usb_pipein(urb->pipe))
2152 					sched = &musb->in_bulk;
2153 				else
2154 					sched = &musb->out_bulk;
2155 				break;
2156 			}
2157 		default:
2158 			/* REVISIT when we get a schedule tree, periodic
2159 			 * transfers won't always be at the head of a
2160 			 * singleton queue...
2161 			 */
2162 			sched = NULL;
2163 			break;
2164 		}
2165 	}
2166 
2167 	/* NOTE:  qh is invalid unless !list_empty(&hep->urb_list) */
2168 	if (ret < 0 || (sched && qh != first_qh(sched))) {
2169 		int	ready = qh->is_ready;
2170 
2171 		ret = 0;
2172 		qh->is_ready = 0;
2173 		__musb_giveback(musb, urb, 0);
2174 		qh->is_ready = ready;
2175 
2176 		/* If nothing else (usually musb_giveback) is using it
2177 		 * and its URB list has emptied, recycle this qh.
2178 		 */
2179 		if (ready && list_empty(&qh->hep->urb_list)) {
2180 			qh->hep->hcpriv = NULL;
2181 			list_del(&qh->ring);
2182 			kfree(qh);
2183 		}
2184 	} else
2185 		ret = musb_cleanup_urb(urb, qh, urb->pipe & USB_DIR_IN);
2186 done:
2187 	spin_unlock_irqrestore(&musb->lock, flags);
2188 	return ret;
2189 }
2190 
2191 /* disable an endpoint */
2192 static void
2193 musb_h_disable(struct usb_hcd *hcd, struct usb_host_endpoint *hep)
2194 {
2195 	u8			epnum = hep->desc.bEndpointAddress;
2196 	unsigned long		flags;
2197 	struct musb		*musb = hcd_to_musb(hcd);
2198 	u8			is_in = epnum & USB_DIR_IN;
2199 	struct musb_qh		*qh;
2200 	struct urb		*urb;
2201 	struct list_head	*sched;
2202 
2203 	spin_lock_irqsave(&musb->lock, flags);
2204 
2205 	qh = hep->hcpriv;
2206 	if (qh == NULL)
2207 		goto exit;
2208 
2209 	switch (qh->type) {
2210 	case USB_ENDPOINT_XFER_CONTROL:
2211 		sched = &musb->control;
2212 		break;
2213 	case USB_ENDPOINT_XFER_BULK:
2214 		if (qh->mux == 1) {
2215 			if (is_in)
2216 				sched = &musb->in_bulk;
2217 			else
2218 				sched = &musb->out_bulk;
2219 			break;
2220 		}
2221 	default:
2222 		/* REVISIT when we get a schedule tree, periodic transfers
2223 		 * won't always be at the head of a singleton queue...
2224 		 */
2225 		sched = NULL;
2226 		break;
2227 	}
2228 
2229 	/* NOTE:  qh is invalid unless !list_empty(&hep->urb_list) */
2230 
2231 	/* kick first urb off the hardware, if needed */
2232 	qh->is_ready = 0;
2233 	if (!sched || qh == first_qh(sched)) {
2234 		urb = next_urb(qh);
2235 
2236 		/* make software (then hardware) stop ASAP */
2237 		if (!urb->unlinked)
2238 			urb->status = -ESHUTDOWN;
2239 
2240 		/* cleanup */
2241 		musb_cleanup_urb(urb, qh, urb->pipe & USB_DIR_IN);
2242 
2243 		/* Then nuke all the others ... and advance the
2244 		 * queue on hw_ep (e.g. bulk ring) when we're done.
2245 		 */
2246 		while (!list_empty(&hep->urb_list)) {
2247 			urb = next_urb(qh);
2248 			urb->status = -ESHUTDOWN;
2249 			musb_advance_schedule(musb, urb, qh->hw_ep, is_in);
2250 		}
2251 	} else {
2252 		/* Just empty the queue; the hardware is busy with
2253 		 * other transfers, and since !qh->is_ready nothing
2254 		 * will activate any of these as it advances.
2255 		 */
2256 		while (!list_empty(&hep->urb_list))
2257 			__musb_giveback(musb, next_urb(qh), -ESHUTDOWN);
2258 
2259 		hep->hcpriv = NULL;
2260 		list_del(&qh->ring);
2261 		kfree(qh);
2262 	}
2263 exit:
2264 	spin_unlock_irqrestore(&musb->lock, flags);
2265 }
2266 
2267 static int musb_h_get_frame_number(struct usb_hcd *hcd)
2268 {
2269 	struct musb	*musb = hcd_to_musb(hcd);
2270 
2271 	return musb_readw(musb->mregs, MUSB_FRAME);
2272 }
2273 
2274 static int musb_h_start(struct usb_hcd *hcd)
2275 {
2276 	struct musb	*musb = hcd_to_musb(hcd);
2277 
2278 	/* NOTE: musb_start() is called when the hub driver turns
2279 	 * on port power, or when (OTG) peripheral starts.
2280 	 */
2281 	hcd->state = HC_STATE_RUNNING;
2282 	musb->port1_status = 0;
2283 	return 0;
2284 }
2285 
2286 static void musb_h_stop(struct usb_hcd *hcd)
2287 {
2288 	musb_stop(hcd_to_musb(hcd));
2289 	hcd->state = HC_STATE_HALT;
2290 }
2291 
2292 static int musb_bus_suspend(struct usb_hcd *hcd)
2293 {
2294 	struct musb	*musb = hcd_to_musb(hcd);
2295 
2296 	if (musb->xceiv.state == OTG_STATE_A_SUSPEND)
2297 		return 0;
2298 
2299 	if (is_host_active(musb) && musb->is_active) {
2300 		WARNING("trying to suspend as %s is_active=%i\n",
2301 			otg_state_string(musb), musb->is_active);
2302 		return -EBUSY;
2303 	} else
2304 		return 0;
2305 }
2306 
2307 static int musb_bus_resume(struct usb_hcd *hcd)
2308 {
2309 	/* resuming child port does the work */
2310 	return 0;
2311 }
2312 
2313 const struct hc_driver musb_hc_driver = {
2314 	.description		= "musb-hcd",
2315 	.product_desc		= "MUSB HDRC host driver",
2316 	.hcd_priv_size		= sizeof(struct musb),
2317 	.flags			= HCD_USB2 | HCD_MEMORY,
2318 
2319 	/* not using irq handler or reset hooks from usbcore, since
2320 	 * those must be shared with peripheral code for OTG configs
2321 	 */
2322 
2323 	.start			= musb_h_start,
2324 	.stop			= musb_h_stop,
2325 
2326 	.get_frame_number	= musb_h_get_frame_number,
2327 
2328 	.urb_enqueue		= musb_urb_enqueue,
2329 	.urb_dequeue		= musb_urb_dequeue,
2330 	.endpoint_disable	= musb_h_disable,
2331 
2332 	.hub_status_data	= musb_hub_status_data,
2333 	.hub_control		= musb_hub_control,
2334 	.bus_suspend		= musb_bus_suspend,
2335 	.bus_resume		= musb_bus_resume,
2336 	/* .start_port_reset	= NULL, */
2337 	/* .hub_irq_enable	= NULL, */
2338 };
2339