xref: /openbmc/linux/drivers/usb/musb/musb_host.c (revision 6a551c11)
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/list.h>
43 #include <linux/dma-mapping.h>
44 
45 #include "musb_core.h"
46 #include "musb_host.h"
47 
48 /* MUSB HOST status 22-mar-2006
49  *
50  * - There's still lots of partial code duplication for fault paths, so
51  *   they aren't handled as consistently as they need to be.
52  *
53  * - PIO mostly behaved when last tested.
54  *     + including ep0, with all usbtest cases 9, 10
55  *     + usbtest 14 (ep0out) doesn't seem to run at all
56  *     + double buffered OUT/TX endpoints saw stalls(!) with certain usbtest
57  *       configurations, but otherwise double buffering passes basic tests.
58  *     + for 2.6.N, for N > ~10, needs API changes for hcd framework.
59  *
60  * - DMA (CPPI) ... partially behaves, not currently recommended
61  *     + about 1/15 the speed of typical EHCI implementations (PCI)
62  *     + RX, all too often reqpkt seems to misbehave after tx
63  *     + TX, no known issues (other than evident silicon issue)
64  *
65  * - DMA (Mentor/OMAP) ...has at least toggle update problems
66  *
67  * - [23-feb-2009] minimal traffic scheduling to avoid bulk RX packet
68  *   starvation ... nothing yet for TX, interrupt, or bulk.
69  *
70  * - Not tested with HNP, but some SRP paths seem to behave.
71  *
72  * NOTE 24-August-2006:
73  *
74  * - Bulk traffic finally uses both sides of hardware ep1, freeing up an
75  *   extra endpoint for periodic use enabling hub + keybd + mouse.  That
76  *   mostly works, except that with "usbnet" it's easy to trigger cases
77  *   with "ping" where RX loses.  (a) ping to davinci, even "ping -f",
78  *   fine; but (b) ping _from_ davinci, even "ping -c 1", ICMP RX loses
79  *   although ARP RX wins.  (That test was done with a full speed link.)
80  */
81 
82 
83 /*
84  * NOTE on endpoint usage:
85  *
86  * CONTROL transfers all go through ep0.  BULK ones go through dedicated IN
87  * and OUT endpoints ... hardware is dedicated for those "async" queue(s).
88  * (Yes, bulk _could_ use more of the endpoints than that, and would even
89  * benefit from it.)
90  *
91  * INTERUPPT and ISOCHRONOUS transfers are scheduled to the other endpoints.
92  * So far that scheduling is both dumb and optimistic:  the endpoint will be
93  * "claimed" until its software queue is no longer refilled.  No multiplexing
94  * of transfers between endpoints, or anything clever.
95  */
96 
97 struct musb *hcd_to_musb(struct usb_hcd *hcd)
98 {
99 	return *(struct musb **) hcd->hcd_priv;
100 }
101 
102 
103 static void musb_ep_program(struct musb *musb, u8 epnum,
104 			struct urb *urb, int is_out,
105 			u8 *buf, u32 offset, u32 len);
106 
107 /*
108  * Clear TX fifo. Needed to avoid BABBLE errors.
109  */
110 static void musb_h_tx_flush_fifo(struct musb_hw_ep *ep)
111 {
112 	struct musb	*musb = ep->musb;
113 	void __iomem	*epio = ep->regs;
114 	u16		csr;
115 	int		retries = 1000;
116 
117 	csr = musb_readw(epio, MUSB_TXCSR);
118 	while (csr & MUSB_TXCSR_FIFONOTEMPTY) {
119 		csr |= MUSB_TXCSR_FLUSHFIFO | MUSB_TXCSR_TXPKTRDY;
120 		musb_writew(epio, MUSB_TXCSR, csr);
121 		csr = musb_readw(epio, MUSB_TXCSR);
122 
123 		/*
124 		 * FIXME: sometimes the tx fifo flush failed, it has been
125 		 * observed during device disconnect on AM335x.
126 		 *
127 		 * To reproduce the issue, ensure tx urb(s) are queued when
128 		 * unplug the usb device which is connected to AM335x usb
129 		 * host port.
130 		 *
131 		 * I found using a usb-ethernet device and running iperf
132 		 * (client on AM335x) has very high chance to trigger it.
133 		 *
134 		 * Better to turn on dev_dbg() in musb_cleanup_urb() with
135 		 * CPPI enabled to see the issue when aborting the tx channel.
136 		 */
137 		if (dev_WARN_ONCE(musb->controller, retries-- < 1,
138 				"Could not flush host TX%d fifo: csr: %04x\n",
139 				ep->epnum, csr))
140 			return;
141 	}
142 }
143 
144 static void musb_h_ep0_flush_fifo(struct musb_hw_ep *ep)
145 {
146 	void __iomem	*epio = ep->regs;
147 	u16		csr;
148 	int		retries = 5;
149 
150 	/* scrub any data left in the fifo */
151 	do {
152 		csr = musb_readw(epio, MUSB_TXCSR);
153 		if (!(csr & (MUSB_CSR0_TXPKTRDY | MUSB_CSR0_RXPKTRDY)))
154 			break;
155 		musb_writew(epio, MUSB_TXCSR, MUSB_CSR0_FLUSHFIFO);
156 		csr = musb_readw(epio, MUSB_TXCSR);
157 		udelay(10);
158 	} while (--retries);
159 
160 	WARN(!retries, "Could not flush host TX%d fifo: csr: %04x\n",
161 			ep->epnum, csr);
162 
163 	/* and reset for the next transfer */
164 	musb_writew(epio, MUSB_TXCSR, 0);
165 }
166 
167 /*
168  * Start transmit. Caller is responsible for locking shared resources.
169  * musb must be locked.
170  */
171 static inline void musb_h_tx_start(struct musb_hw_ep *ep)
172 {
173 	u16	txcsr;
174 
175 	/* NOTE: no locks here; caller should lock and select EP */
176 	if (ep->epnum) {
177 		txcsr = musb_readw(ep->regs, MUSB_TXCSR);
178 		txcsr |= MUSB_TXCSR_TXPKTRDY | MUSB_TXCSR_H_WZC_BITS;
179 		musb_writew(ep->regs, MUSB_TXCSR, txcsr);
180 	} else {
181 		txcsr = MUSB_CSR0_H_SETUPPKT | MUSB_CSR0_TXPKTRDY;
182 		musb_writew(ep->regs, MUSB_CSR0, txcsr);
183 	}
184 
185 }
186 
187 static inline void musb_h_tx_dma_start(struct musb_hw_ep *ep)
188 {
189 	u16	txcsr;
190 
191 	/* NOTE: no locks here; caller should lock and select EP */
192 	txcsr = musb_readw(ep->regs, MUSB_TXCSR);
193 	txcsr |= MUSB_TXCSR_DMAENAB | MUSB_TXCSR_H_WZC_BITS;
194 	if (is_cppi_enabled(ep->musb))
195 		txcsr |= MUSB_TXCSR_DMAMODE;
196 	musb_writew(ep->regs, MUSB_TXCSR, txcsr);
197 }
198 
199 static void musb_ep_set_qh(struct musb_hw_ep *ep, int is_in, struct musb_qh *qh)
200 {
201 	if (is_in != 0 || ep->is_shared_fifo)
202 		ep->in_qh  = qh;
203 	if (is_in == 0 || ep->is_shared_fifo)
204 		ep->out_qh = qh;
205 }
206 
207 static struct musb_qh *musb_ep_get_qh(struct musb_hw_ep *ep, int is_in)
208 {
209 	return is_in ? ep->in_qh : ep->out_qh;
210 }
211 
212 /*
213  * Start the URB at the front of an endpoint's queue
214  * end must be claimed from the caller.
215  *
216  * Context: controller locked, irqs blocked
217  */
218 static void
219 musb_start_urb(struct musb *musb, int is_in, struct musb_qh *qh)
220 {
221 	u16			frame;
222 	u32			len;
223 	void __iomem		*mbase =  musb->mregs;
224 	struct urb		*urb = next_urb(qh);
225 	void			*buf = urb->transfer_buffer;
226 	u32			offset = 0;
227 	struct musb_hw_ep	*hw_ep = qh->hw_ep;
228 	unsigned		pipe = urb->pipe;
229 	u8			address = usb_pipedevice(pipe);
230 	int			epnum = hw_ep->epnum;
231 
232 	/* initialize software qh state */
233 	qh->offset = 0;
234 	qh->segsize = 0;
235 
236 	/* gather right source of data */
237 	switch (qh->type) {
238 	case USB_ENDPOINT_XFER_CONTROL:
239 		/* control transfers always start with SETUP */
240 		is_in = 0;
241 		musb->ep0_stage = MUSB_EP0_START;
242 		buf = urb->setup_packet;
243 		len = 8;
244 		break;
245 	case USB_ENDPOINT_XFER_ISOC:
246 		qh->iso_idx = 0;
247 		qh->frame = 0;
248 		offset = urb->iso_frame_desc[0].offset;
249 		len = urb->iso_frame_desc[0].length;
250 		break;
251 	default:		/* bulk, interrupt */
252 		/* actual_length may be nonzero on retry paths */
253 		buf = urb->transfer_buffer + urb->actual_length;
254 		len = urb->transfer_buffer_length - urb->actual_length;
255 	}
256 
257 	dev_dbg(musb->controller, "qh %p urb %p dev%d ep%d%s%s, hw_ep %d, %p/%d\n",
258 			qh, urb, address, qh->epnum,
259 			is_in ? "in" : "out",
260 			({char *s; switch (qh->type) {
261 			case USB_ENDPOINT_XFER_CONTROL:	s = ""; break;
262 			case USB_ENDPOINT_XFER_BULK:	s = "-bulk"; break;
263 			case USB_ENDPOINT_XFER_ISOC:	s = "-iso"; break;
264 			default:			s = "-intr"; break;
265 			} s; }),
266 			epnum, buf + offset, len);
267 
268 	/* Configure endpoint */
269 	musb_ep_set_qh(hw_ep, is_in, qh);
270 	musb_ep_program(musb, epnum, urb, !is_in, buf, offset, len);
271 
272 	/* transmit may have more work: start it when it is time */
273 	if (is_in)
274 		return;
275 
276 	/* determine if the time is right for a periodic transfer */
277 	switch (qh->type) {
278 	case USB_ENDPOINT_XFER_ISOC:
279 	case USB_ENDPOINT_XFER_INT:
280 		dev_dbg(musb->controller, "check whether there's still time for periodic Tx\n");
281 		frame = musb_readw(mbase, MUSB_FRAME);
282 		/* FIXME this doesn't implement that scheduling policy ...
283 		 * or handle framecounter wrapping
284 		 */
285 		if (1) {	/* Always assume URB_ISO_ASAP */
286 			/* REVISIT the SOF irq handler shouldn't duplicate
287 			 * this code; and we don't init urb->start_frame...
288 			 */
289 			qh->frame = 0;
290 			goto start;
291 		} else {
292 			qh->frame = urb->start_frame;
293 			/* enable SOF interrupt so we can count down */
294 			dev_dbg(musb->controller, "SOF for %d\n", epnum);
295 #if 1 /* ifndef	CONFIG_ARCH_DAVINCI */
296 			musb_writeb(mbase, MUSB_INTRUSBE, 0xff);
297 #endif
298 		}
299 		break;
300 	default:
301 start:
302 		dev_dbg(musb->controller, "Start TX%d %s\n", epnum,
303 			hw_ep->tx_channel ? "dma" : "pio");
304 
305 		if (!hw_ep->tx_channel)
306 			musb_h_tx_start(hw_ep);
307 		else if (is_cppi_enabled(musb) || tusb_dma_omap(musb))
308 			musb_h_tx_dma_start(hw_ep);
309 	}
310 }
311 
312 /* Context: caller owns controller lock, IRQs are blocked */
313 static void musb_giveback(struct musb *musb, struct urb *urb, int status)
314 __releases(musb->lock)
315 __acquires(musb->lock)
316 {
317 	dev_dbg(musb->controller,
318 			"complete %p %pF (%d), dev%d ep%d%s, %d/%d\n",
319 			urb, urb->complete, status,
320 			usb_pipedevice(urb->pipe),
321 			usb_pipeendpoint(urb->pipe),
322 			usb_pipein(urb->pipe) ? "in" : "out",
323 			urb->actual_length, urb->transfer_buffer_length
324 			);
325 
326 	usb_hcd_unlink_urb_from_ep(musb->hcd, urb);
327 	spin_unlock(&musb->lock);
328 	usb_hcd_giveback_urb(musb->hcd, urb, status);
329 	spin_lock(&musb->lock);
330 }
331 
332 /* For bulk/interrupt endpoints only */
333 static inline void musb_save_toggle(struct musb_qh *qh, int is_in,
334 				    struct urb *urb)
335 {
336 	void __iomem		*epio = qh->hw_ep->regs;
337 	u16			csr;
338 
339 	/*
340 	 * FIXME: the current Mentor DMA code seems to have
341 	 * problems getting toggle correct.
342 	 */
343 
344 	if (is_in)
345 		csr = musb_readw(epio, MUSB_RXCSR) & MUSB_RXCSR_H_DATATOGGLE;
346 	else
347 		csr = musb_readw(epio, MUSB_TXCSR) & MUSB_TXCSR_H_DATATOGGLE;
348 
349 	usb_settoggle(urb->dev, qh->epnum, !is_in, csr ? 1 : 0);
350 }
351 
352 /*
353  * Advance this hardware endpoint's queue, completing the specified URB and
354  * advancing to either the next URB queued to that qh, or else invalidating
355  * that qh and advancing to the next qh scheduled after the current one.
356  *
357  * Context: caller owns controller lock, IRQs are blocked
358  */
359 static void musb_advance_schedule(struct musb *musb, struct urb *urb,
360 				  struct musb_hw_ep *hw_ep, int is_in)
361 {
362 	struct musb_qh		*qh = musb_ep_get_qh(hw_ep, is_in);
363 	struct musb_hw_ep	*ep = qh->hw_ep;
364 	int			ready = qh->is_ready;
365 	int			status;
366 
367 	status = (urb->status == -EINPROGRESS) ? 0 : urb->status;
368 
369 	/* save toggle eagerly, for paranoia */
370 	switch (qh->type) {
371 	case USB_ENDPOINT_XFER_BULK:
372 	case USB_ENDPOINT_XFER_INT:
373 		musb_save_toggle(qh, is_in, urb);
374 		break;
375 	case USB_ENDPOINT_XFER_ISOC:
376 		if (status == 0 && urb->error_count)
377 			status = -EXDEV;
378 		break;
379 	}
380 
381 	qh->is_ready = 0;
382 	musb_giveback(musb, urb, status);
383 	qh->is_ready = ready;
384 
385 	/* reclaim resources (and bandwidth) ASAP; deschedule it, and
386 	 * invalidate qh as soon as list_empty(&hep->urb_list)
387 	 */
388 	if (list_empty(&qh->hep->urb_list)) {
389 		struct list_head	*head;
390 		struct dma_controller	*dma = musb->dma_controller;
391 
392 		if (is_in) {
393 			ep->rx_reinit = 1;
394 			if (ep->rx_channel) {
395 				dma->channel_release(ep->rx_channel);
396 				ep->rx_channel = NULL;
397 			}
398 		} else {
399 			ep->tx_reinit = 1;
400 			if (ep->tx_channel) {
401 				dma->channel_release(ep->tx_channel);
402 				ep->tx_channel = NULL;
403 			}
404 		}
405 
406 		/* Clobber old pointers to this qh */
407 		musb_ep_set_qh(ep, is_in, NULL);
408 		qh->hep->hcpriv = NULL;
409 
410 		switch (qh->type) {
411 
412 		case USB_ENDPOINT_XFER_CONTROL:
413 		case USB_ENDPOINT_XFER_BULK:
414 			/* fifo policy for these lists, except that NAKing
415 			 * should rotate a qh to the end (for fairness).
416 			 */
417 			if (qh->mux == 1) {
418 				head = qh->ring.prev;
419 				list_del(&qh->ring);
420 				kfree(qh);
421 				qh = first_qh(head);
422 				break;
423 			}
424 
425 		case USB_ENDPOINT_XFER_ISOC:
426 		case USB_ENDPOINT_XFER_INT:
427 			/* this is where periodic bandwidth should be
428 			 * de-allocated if it's tracked and allocated;
429 			 * and where we'd update the schedule tree...
430 			 */
431 			kfree(qh);
432 			qh = NULL;
433 			break;
434 		}
435 	}
436 
437 	/*
438 	 * The pipe must be broken if current urb->status is set, so don't
439 	 * start next urb.
440 	 * TODO: to minimize the risk of regression, only check urb->status
441 	 * for RX, until we have a test case to understand the behavior of TX.
442 	 */
443 	if ((!status || !is_in) && qh && qh->is_ready) {
444 		dev_dbg(musb->controller, "... next ep%d %cX urb %p\n",
445 		    hw_ep->epnum, is_in ? 'R' : 'T', next_urb(qh));
446 		musb_start_urb(musb, is_in, qh);
447 	}
448 }
449 
450 static u16 musb_h_flush_rxfifo(struct musb_hw_ep *hw_ep, u16 csr)
451 {
452 	/* we don't want fifo to fill itself again;
453 	 * ignore dma (various models),
454 	 * leave toggle alone (may not have been saved yet)
455 	 */
456 	csr |= MUSB_RXCSR_FLUSHFIFO | MUSB_RXCSR_RXPKTRDY;
457 	csr &= ~(MUSB_RXCSR_H_REQPKT
458 		| MUSB_RXCSR_H_AUTOREQ
459 		| MUSB_RXCSR_AUTOCLEAR);
460 
461 	/* write 2x to allow double buffering */
462 	musb_writew(hw_ep->regs, MUSB_RXCSR, csr);
463 	musb_writew(hw_ep->regs, MUSB_RXCSR, csr);
464 
465 	/* flush writebuffer */
466 	return musb_readw(hw_ep->regs, MUSB_RXCSR);
467 }
468 
469 /*
470  * PIO RX for a packet (or part of it).
471  */
472 static bool
473 musb_host_packet_rx(struct musb *musb, struct urb *urb, u8 epnum, u8 iso_err)
474 {
475 	u16			rx_count;
476 	u8			*buf;
477 	u16			csr;
478 	bool			done = false;
479 	u32			length;
480 	int			do_flush = 0;
481 	struct musb_hw_ep	*hw_ep = musb->endpoints + epnum;
482 	void __iomem		*epio = hw_ep->regs;
483 	struct musb_qh		*qh = hw_ep->in_qh;
484 	int			pipe = urb->pipe;
485 	void			*buffer = urb->transfer_buffer;
486 
487 	/* musb_ep_select(mbase, epnum); */
488 	rx_count = musb_readw(epio, MUSB_RXCOUNT);
489 	dev_dbg(musb->controller, "RX%d count %d, buffer %p len %d/%d\n", epnum, rx_count,
490 			urb->transfer_buffer, qh->offset,
491 			urb->transfer_buffer_length);
492 
493 	/* unload FIFO */
494 	if (usb_pipeisoc(pipe)) {
495 		int					status = 0;
496 		struct usb_iso_packet_descriptor	*d;
497 
498 		if (iso_err) {
499 			status = -EILSEQ;
500 			urb->error_count++;
501 		}
502 
503 		d = urb->iso_frame_desc + qh->iso_idx;
504 		buf = buffer + d->offset;
505 		length = d->length;
506 		if (rx_count > length) {
507 			if (status == 0) {
508 				status = -EOVERFLOW;
509 				urb->error_count++;
510 			}
511 			dev_dbg(musb->controller, "** OVERFLOW %d into %d\n", rx_count, length);
512 			do_flush = 1;
513 		} else
514 			length = rx_count;
515 		urb->actual_length += length;
516 		d->actual_length = length;
517 
518 		d->status = status;
519 
520 		/* see if we are done */
521 		done = (++qh->iso_idx >= urb->number_of_packets);
522 	} else {
523 		/* non-isoch */
524 		buf = buffer + qh->offset;
525 		length = urb->transfer_buffer_length - qh->offset;
526 		if (rx_count > length) {
527 			if (urb->status == -EINPROGRESS)
528 				urb->status = -EOVERFLOW;
529 			dev_dbg(musb->controller, "** OVERFLOW %d into %d\n", rx_count, length);
530 			do_flush = 1;
531 		} else
532 			length = rx_count;
533 		urb->actual_length += length;
534 		qh->offset += length;
535 
536 		/* see if we are done */
537 		done = (urb->actual_length == urb->transfer_buffer_length)
538 			|| (rx_count < qh->maxpacket)
539 			|| (urb->status != -EINPROGRESS);
540 		if (done
541 				&& (urb->status == -EINPROGRESS)
542 				&& (urb->transfer_flags & URB_SHORT_NOT_OK)
543 				&& (urb->actual_length
544 					< urb->transfer_buffer_length))
545 			urb->status = -EREMOTEIO;
546 	}
547 
548 	musb_read_fifo(hw_ep, length, buf);
549 
550 	csr = musb_readw(epio, MUSB_RXCSR);
551 	csr |= MUSB_RXCSR_H_WZC_BITS;
552 	if (unlikely(do_flush))
553 		musb_h_flush_rxfifo(hw_ep, csr);
554 	else {
555 		/* REVISIT this assumes AUTOCLEAR is never set */
556 		csr &= ~(MUSB_RXCSR_RXPKTRDY | MUSB_RXCSR_H_REQPKT);
557 		if (!done)
558 			csr |= MUSB_RXCSR_H_REQPKT;
559 		musb_writew(epio, MUSB_RXCSR, csr);
560 	}
561 
562 	return done;
563 }
564 
565 /* we don't always need to reinit a given side of an endpoint...
566  * when we do, use tx/rx reinit routine and then construct a new CSR
567  * to address data toggle, NYET, and DMA or PIO.
568  *
569  * it's possible that driver bugs (especially for DMA) or aborting a
570  * transfer might have left the endpoint busier than it should be.
571  * the busy/not-empty tests are basically paranoia.
572  */
573 static void
574 musb_rx_reinit(struct musb *musb, struct musb_qh *qh, u8 epnum)
575 {
576 	struct musb_hw_ep *ep = musb->endpoints + epnum;
577 	u16	csr;
578 
579 	/* NOTE:  we know the "rx" fifo reinit never triggers for ep0.
580 	 * That always uses tx_reinit since ep0 repurposes TX register
581 	 * offsets; the initial SETUP packet is also a kind of OUT.
582 	 */
583 
584 	/* if programmed for Tx, put it in RX mode */
585 	if (ep->is_shared_fifo) {
586 		csr = musb_readw(ep->regs, MUSB_TXCSR);
587 		if (csr & MUSB_TXCSR_MODE) {
588 			musb_h_tx_flush_fifo(ep);
589 			csr = musb_readw(ep->regs, MUSB_TXCSR);
590 			musb_writew(ep->regs, MUSB_TXCSR,
591 				    csr | MUSB_TXCSR_FRCDATATOG);
592 		}
593 
594 		/*
595 		 * Clear the MODE bit (and everything else) to enable Rx.
596 		 * NOTE: we mustn't clear the DMAMODE bit before DMAENAB.
597 		 */
598 		if (csr & MUSB_TXCSR_DMAMODE)
599 			musb_writew(ep->regs, MUSB_TXCSR, MUSB_TXCSR_DMAMODE);
600 		musb_writew(ep->regs, MUSB_TXCSR, 0);
601 
602 	/* scrub all previous state, clearing toggle */
603 	}
604 	csr = musb_readw(ep->regs, MUSB_RXCSR);
605 	if (csr & MUSB_RXCSR_RXPKTRDY)
606 		WARNING("rx%d, packet/%d ready?\n", ep->epnum,
607 			musb_readw(ep->regs, MUSB_RXCOUNT));
608 
609 	musb_h_flush_rxfifo(ep, MUSB_RXCSR_CLRDATATOG);
610 
611 	/* target addr and (for multipoint) hub addr/port */
612 	if (musb->is_multipoint) {
613 		musb_write_rxfunaddr(musb, epnum, qh->addr_reg);
614 		musb_write_rxhubaddr(musb, epnum, qh->h_addr_reg);
615 		musb_write_rxhubport(musb, epnum, qh->h_port_reg);
616 	} else
617 		musb_writeb(musb->mregs, MUSB_FADDR, qh->addr_reg);
618 
619 	/* protocol/endpoint, interval/NAKlimit, i/o size */
620 	musb_writeb(ep->regs, MUSB_RXTYPE, qh->type_reg);
621 	musb_writeb(ep->regs, MUSB_RXINTERVAL, qh->intv_reg);
622 	/* NOTE: bulk combining rewrites high bits of maxpacket */
623 	/* Set RXMAXP with the FIFO size of the endpoint
624 	 * to disable double buffer mode.
625 	 */
626 	if (musb->double_buffer_not_ok)
627 		musb_writew(ep->regs, MUSB_RXMAXP, ep->max_packet_sz_rx);
628 	else
629 		musb_writew(ep->regs, MUSB_RXMAXP,
630 				qh->maxpacket | ((qh->hb_mult - 1) << 11));
631 
632 	ep->rx_reinit = 0;
633 }
634 
635 static void musb_tx_dma_set_mode_mentor(struct dma_controller *dma,
636 		struct musb_hw_ep *hw_ep, struct musb_qh *qh,
637 		struct urb *urb, u32 offset,
638 		u32 *length, u8 *mode)
639 {
640 	struct dma_channel	*channel = hw_ep->tx_channel;
641 	void __iomem		*epio = hw_ep->regs;
642 	u16			pkt_size = qh->maxpacket;
643 	u16			csr;
644 
645 	if (*length > channel->max_len)
646 		*length = channel->max_len;
647 
648 	csr = musb_readw(epio, MUSB_TXCSR);
649 	if (*length > pkt_size) {
650 		*mode = 1;
651 		csr |= MUSB_TXCSR_DMAMODE | MUSB_TXCSR_DMAENAB;
652 		/* autoset shouldn't be set in high bandwidth */
653 		/*
654 		 * Enable Autoset according to table
655 		 * below
656 		 * bulk_split hb_mult	Autoset_Enable
657 		 *	0	1	Yes(Normal)
658 		 *	0	>1	No(High BW ISO)
659 		 *	1	1	Yes(HS bulk)
660 		 *	1	>1	Yes(FS bulk)
661 		 */
662 		if (qh->hb_mult == 1 || (qh->hb_mult > 1 &&
663 					can_bulk_split(hw_ep->musb, qh->type)))
664 			csr |= MUSB_TXCSR_AUTOSET;
665 	} else {
666 		*mode = 0;
667 		csr &= ~(MUSB_TXCSR_AUTOSET | MUSB_TXCSR_DMAMODE);
668 		csr |= MUSB_TXCSR_DMAENAB; /* against programmer's guide */
669 	}
670 	channel->desired_mode = *mode;
671 	musb_writew(epio, MUSB_TXCSR, csr);
672 }
673 
674 static void musb_tx_dma_set_mode_cppi_tusb(struct dma_controller *dma,
675 					   struct musb_hw_ep *hw_ep,
676 					   struct musb_qh *qh,
677 					   struct urb *urb,
678 					   u32 offset,
679 					   u32 *length,
680 					   u8 *mode)
681 {
682 	struct dma_channel *channel = hw_ep->tx_channel;
683 
684 	channel->actual_len = 0;
685 
686 	/*
687 	 * TX uses "RNDIS" mode automatically but needs help
688 	 * to identify the zero-length-final-packet case.
689 	 */
690 	*mode = (urb->transfer_flags & URB_ZERO_PACKET) ? 1 : 0;
691 }
692 
693 static bool musb_tx_dma_program(struct dma_controller *dma,
694 		struct musb_hw_ep *hw_ep, struct musb_qh *qh,
695 		struct urb *urb, u32 offset, u32 length)
696 {
697 	struct dma_channel	*channel = hw_ep->tx_channel;
698 	u16			pkt_size = qh->maxpacket;
699 	u8			mode;
700 
701 	if (musb_dma_inventra(hw_ep->musb) || musb_dma_ux500(hw_ep->musb))
702 		musb_tx_dma_set_mode_mentor(dma, hw_ep, qh, urb, offset,
703 					    &length, &mode);
704 	else if (is_cppi_enabled(hw_ep->musb) || tusb_dma_omap(hw_ep->musb))
705 		musb_tx_dma_set_mode_cppi_tusb(dma, hw_ep, qh, urb, offset,
706 					       &length, &mode);
707 	else
708 		return false;
709 
710 	qh->segsize = length;
711 
712 	/*
713 	 * Ensure the data reaches to main memory before starting
714 	 * DMA transfer
715 	 */
716 	wmb();
717 
718 	if (!dma->channel_program(channel, pkt_size, mode,
719 			urb->transfer_dma + offset, length)) {
720 		void __iomem *epio = hw_ep->regs;
721 		u16 csr;
722 
723 		dma->channel_release(channel);
724 		hw_ep->tx_channel = NULL;
725 
726 		csr = musb_readw(epio, MUSB_TXCSR);
727 		csr &= ~(MUSB_TXCSR_AUTOSET | MUSB_TXCSR_DMAENAB);
728 		musb_writew(epio, MUSB_TXCSR, csr | MUSB_TXCSR_H_WZC_BITS);
729 		return false;
730 	}
731 	return true;
732 }
733 
734 /*
735  * Program an HDRC endpoint as per the given URB
736  * Context: irqs blocked, controller lock held
737  */
738 static void musb_ep_program(struct musb *musb, u8 epnum,
739 			struct urb *urb, int is_out,
740 			u8 *buf, u32 offset, u32 len)
741 {
742 	struct dma_controller	*dma_controller;
743 	struct dma_channel	*dma_channel;
744 	u8			dma_ok;
745 	void __iomem		*mbase = musb->mregs;
746 	struct musb_hw_ep	*hw_ep = musb->endpoints + epnum;
747 	void __iomem		*epio = hw_ep->regs;
748 	struct musb_qh		*qh = musb_ep_get_qh(hw_ep, !is_out);
749 	u16			packet_sz = qh->maxpacket;
750 	u8			use_dma = 1;
751 	u16			csr;
752 
753 	dev_dbg(musb->controller, "%s hw%d urb %p spd%d dev%d ep%d%s "
754 				"h_addr%02x h_port%02x bytes %d\n",
755 			is_out ? "-->" : "<--",
756 			epnum, urb, urb->dev->speed,
757 			qh->addr_reg, qh->epnum, is_out ? "out" : "in",
758 			qh->h_addr_reg, qh->h_port_reg,
759 			len);
760 
761 	musb_ep_select(mbase, epnum);
762 
763 	if (is_out && !len) {
764 		use_dma = 0;
765 		csr = musb_readw(epio, MUSB_TXCSR);
766 		csr &= ~MUSB_TXCSR_DMAENAB;
767 		musb_writew(epio, MUSB_TXCSR, csr);
768 		hw_ep->tx_channel = NULL;
769 	}
770 
771 	/* candidate for DMA? */
772 	dma_controller = musb->dma_controller;
773 	if (use_dma && is_dma_capable() && epnum && dma_controller) {
774 		dma_channel = is_out ? hw_ep->tx_channel : hw_ep->rx_channel;
775 		if (!dma_channel) {
776 			dma_channel = dma_controller->channel_alloc(
777 					dma_controller, hw_ep, is_out);
778 			if (is_out)
779 				hw_ep->tx_channel = dma_channel;
780 			else
781 				hw_ep->rx_channel = dma_channel;
782 		}
783 	} else
784 		dma_channel = NULL;
785 
786 	/* make sure we clear DMAEnab, autoSet bits from previous run */
787 
788 	/* OUT/transmit/EP0 or IN/receive? */
789 	if (is_out) {
790 		u16	csr;
791 		u16	int_txe;
792 		u16	load_count;
793 
794 		csr = musb_readw(epio, MUSB_TXCSR);
795 
796 		/* disable interrupt in case we flush */
797 		int_txe = musb->intrtxe;
798 		musb_writew(mbase, MUSB_INTRTXE, int_txe & ~(1 << epnum));
799 
800 		/* general endpoint setup */
801 		if (epnum) {
802 			/* flush all old state, set default */
803 			/*
804 			 * We could be flushing valid
805 			 * packets in double buffering
806 			 * case
807 			 */
808 			if (!hw_ep->tx_double_buffered)
809 				musb_h_tx_flush_fifo(hw_ep);
810 
811 			/*
812 			 * We must not clear the DMAMODE bit before or in
813 			 * the same cycle with the DMAENAB bit, so we clear
814 			 * the latter first...
815 			 */
816 			csr &= ~(MUSB_TXCSR_H_NAKTIMEOUT
817 					| MUSB_TXCSR_AUTOSET
818 					| MUSB_TXCSR_DMAENAB
819 					| MUSB_TXCSR_FRCDATATOG
820 					| MUSB_TXCSR_H_RXSTALL
821 					| MUSB_TXCSR_H_ERROR
822 					| MUSB_TXCSR_TXPKTRDY
823 					);
824 			csr |= MUSB_TXCSR_MODE;
825 
826 			if (!hw_ep->tx_double_buffered) {
827 				if (usb_gettoggle(urb->dev, qh->epnum, 1))
828 					csr |= MUSB_TXCSR_H_WR_DATATOGGLE
829 						| MUSB_TXCSR_H_DATATOGGLE;
830 				else
831 					csr |= MUSB_TXCSR_CLRDATATOG;
832 			}
833 
834 			musb_writew(epio, MUSB_TXCSR, csr);
835 			/* REVISIT may need to clear FLUSHFIFO ... */
836 			csr &= ~MUSB_TXCSR_DMAMODE;
837 			musb_writew(epio, MUSB_TXCSR, csr);
838 			csr = musb_readw(epio, MUSB_TXCSR);
839 		} else {
840 			/* endpoint 0: just flush */
841 			musb_h_ep0_flush_fifo(hw_ep);
842 		}
843 
844 		/* target addr and (for multipoint) hub addr/port */
845 		if (musb->is_multipoint) {
846 			musb_write_txfunaddr(musb, epnum, qh->addr_reg);
847 			musb_write_txhubaddr(musb, epnum, qh->h_addr_reg);
848 			musb_write_txhubport(musb, epnum, qh->h_port_reg);
849 /* FIXME if !epnum, do the same for RX ... */
850 		} else
851 			musb_writeb(mbase, MUSB_FADDR, qh->addr_reg);
852 
853 		/* protocol/endpoint/interval/NAKlimit */
854 		if (epnum) {
855 			musb_writeb(epio, MUSB_TXTYPE, qh->type_reg);
856 			if (musb->double_buffer_not_ok) {
857 				musb_writew(epio, MUSB_TXMAXP,
858 						hw_ep->max_packet_sz_tx);
859 			} else if (can_bulk_split(musb, qh->type)) {
860 				qh->hb_mult = hw_ep->max_packet_sz_tx
861 						/ packet_sz;
862 				musb_writew(epio, MUSB_TXMAXP, packet_sz
863 					| ((qh->hb_mult) - 1) << 11);
864 			} else {
865 				musb_writew(epio, MUSB_TXMAXP,
866 						qh->maxpacket |
867 						((qh->hb_mult - 1) << 11));
868 			}
869 			musb_writeb(epio, MUSB_TXINTERVAL, qh->intv_reg);
870 		} else {
871 			musb_writeb(epio, MUSB_NAKLIMIT0, qh->intv_reg);
872 			if (musb->is_multipoint)
873 				musb_writeb(epio, MUSB_TYPE0,
874 						qh->type_reg);
875 		}
876 
877 		if (can_bulk_split(musb, qh->type))
878 			load_count = min((u32) hw_ep->max_packet_sz_tx,
879 						len);
880 		else
881 			load_count = min((u32) packet_sz, len);
882 
883 		if (dma_channel && musb_tx_dma_program(dma_controller,
884 					hw_ep, qh, urb, offset, len))
885 			load_count = 0;
886 
887 		if (load_count) {
888 			/* PIO to load FIFO */
889 			qh->segsize = load_count;
890 			if (!buf) {
891 				sg_miter_start(&qh->sg_miter, urb->sg, 1,
892 						SG_MITER_ATOMIC
893 						| SG_MITER_FROM_SG);
894 				if (!sg_miter_next(&qh->sg_miter)) {
895 					dev_err(musb->controller,
896 							"error: sg"
897 							"list empty\n");
898 					sg_miter_stop(&qh->sg_miter);
899 					goto finish;
900 				}
901 				buf = qh->sg_miter.addr + urb->sg->offset +
902 					urb->actual_length;
903 				load_count = min_t(u32, load_count,
904 						qh->sg_miter.length);
905 				musb_write_fifo(hw_ep, load_count, buf);
906 				qh->sg_miter.consumed = load_count;
907 				sg_miter_stop(&qh->sg_miter);
908 			} else
909 				musb_write_fifo(hw_ep, load_count, buf);
910 		}
911 finish:
912 		/* re-enable interrupt */
913 		musb_writew(mbase, MUSB_INTRTXE, int_txe);
914 
915 	/* IN/receive */
916 	} else {
917 		u16	csr;
918 
919 		if (hw_ep->rx_reinit) {
920 			musb_rx_reinit(musb, qh, epnum);
921 
922 			/* init new state: toggle and NYET, maybe DMA later */
923 			if (usb_gettoggle(urb->dev, qh->epnum, 0))
924 				csr = MUSB_RXCSR_H_WR_DATATOGGLE
925 					| MUSB_RXCSR_H_DATATOGGLE;
926 			else
927 				csr = 0;
928 			if (qh->type == USB_ENDPOINT_XFER_INT)
929 				csr |= MUSB_RXCSR_DISNYET;
930 
931 		} else {
932 			csr = musb_readw(hw_ep->regs, MUSB_RXCSR);
933 
934 			if (csr & (MUSB_RXCSR_RXPKTRDY
935 					| MUSB_RXCSR_DMAENAB
936 					| MUSB_RXCSR_H_REQPKT))
937 				ERR("broken !rx_reinit, ep%d csr %04x\n",
938 						hw_ep->epnum, csr);
939 
940 			/* scrub any stale state, leaving toggle alone */
941 			csr &= MUSB_RXCSR_DISNYET;
942 		}
943 
944 		/* kick things off */
945 
946 		if ((is_cppi_enabled(musb) || tusb_dma_omap(musb)) && dma_channel) {
947 			/* Candidate for DMA */
948 			dma_channel->actual_len = 0L;
949 			qh->segsize = len;
950 
951 			/* AUTOREQ is in a DMA register */
952 			musb_writew(hw_ep->regs, MUSB_RXCSR, csr);
953 			csr = musb_readw(hw_ep->regs, MUSB_RXCSR);
954 
955 			/*
956 			 * Unless caller treats short RX transfers as
957 			 * errors, we dare not queue multiple transfers.
958 			 */
959 			dma_ok = dma_controller->channel_program(dma_channel,
960 					packet_sz, !(urb->transfer_flags &
961 						     URB_SHORT_NOT_OK),
962 					urb->transfer_dma + offset,
963 					qh->segsize);
964 			if (!dma_ok) {
965 				dma_controller->channel_release(dma_channel);
966 				hw_ep->rx_channel = dma_channel = NULL;
967 			} else
968 				csr |= MUSB_RXCSR_DMAENAB;
969 		}
970 
971 		csr |= MUSB_RXCSR_H_REQPKT;
972 		dev_dbg(musb->controller, "RXCSR%d := %04x\n", epnum, csr);
973 		musb_writew(hw_ep->regs, MUSB_RXCSR, csr);
974 		csr = musb_readw(hw_ep->regs, MUSB_RXCSR);
975 	}
976 }
977 
978 /* Schedule next QH from musb->in_bulk/out_bulk and move the current qh to
979  * the end; avoids starvation for other endpoints.
980  */
981 static void musb_bulk_nak_timeout(struct musb *musb, struct musb_hw_ep *ep,
982 	int is_in)
983 {
984 	struct dma_channel	*dma;
985 	struct urb		*urb;
986 	void __iomem		*mbase = musb->mregs;
987 	void __iomem		*epio = ep->regs;
988 	struct musb_qh		*cur_qh, *next_qh;
989 	u16			rx_csr, tx_csr;
990 
991 	musb_ep_select(mbase, ep->epnum);
992 	if (is_in) {
993 		dma = is_dma_capable() ? ep->rx_channel : NULL;
994 
995 		/*
996 		 * Need to stop the transaction by clearing REQPKT first
997 		 * then the NAK Timeout bit ref MUSBMHDRC USB 2.0 HIGH-SPEED
998 		 * DUAL-ROLE CONTROLLER Programmer's Guide, section 9.2.2
999 		 */
1000 		rx_csr = musb_readw(epio, MUSB_RXCSR);
1001 		rx_csr |= MUSB_RXCSR_H_WZC_BITS;
1002 		rx_csr &= ~MUSB_RXCSR_H_REQPKT;
1003 		musb_writew(epio, MUSB_RXCSR, rx_csr);
1004 		rx_csr &= ~MUSB_RXCSR_DATAERROR;
1005 		musb_writew(epio, MUSB_RXCSR, rx_csr);
1006 
1007 		cur_qh = first_qh(&musb->in_bulk);
1008 	} else {
1009 		dma = is_dma_capable() ? ep->tx_channel : NULL;
1010 
1011 		/* clear nak timeout bit */
1012 		tx_csr = musb_readw(epio, MUSB_TXCSR);
1013 		tx_csr |= MUSB_TXCSR_H_WZC_BITS;
1014 		tx_csr &= ~MUSB_TXCSR_H_NAKTIMEOUT;
1015 		musb_writew(epio, MUSB_TXCSR, tx_csr);
1016 
1017 		cur_qh = first_qh(&musb->out_bulk);
1018 	}
1019 	if (cur_qh) {
1020 		urb = next_urb(cur_qh);
1021 		if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1022 			dma->status = MUSB_DMA_STATUS_CORE_ABORT;
1023 			musb->dma_controller->channel_abort(dma);
1024 			urb->actual_length += dma->actual_len;
1025 			dma->actual_len = 0L;
1026 		}
1027 		musb_save_toggle(cur_qh, is_in, urb);
1028 
1029 		if (is_in) {
1030 			/* move cur_qh to end of queue */
1031 			list_move_tail(&cur_qh->ring, &musb->in_bulk);
1032 
1033 			/* get the next qh from musb->in_bulk */
1034 			next_qh = first_qh(&musb->in_bulk);
1035 
1036 			/* set rx_reinit and schedule the next qh */
1037 			ep->rx_reinit = 1;
1038 		} else {
1039 			/* move cur_qh to end of queue */
1040 			list_move_tail(&cur_qh->ring, &musb->out_bulk);
1041 
1042 			/* get the next qh from musb->out_bulk */
1043 			next_qh = first_qh(&musb->out_bulk);
1044 
1045 			/* set tx_reinit and schedule the next qh */
1046 			ep->tx_reinit = 1;
1047 		}
1048 		musb_start_urb(musb, is_in, next_qh);
1049 	}
1050 }
1051 
1052 /*
1053  * Service the default endpoint (ep0) as host.
1054  * Return true until it's time to start the status stage.
1055  */
1056 static bool musb_h_ep0_continue(struct musb *musb, u16 len, struct urb *urb)
1057 {
1058 	bool			 more = false;
1059 	u8			*fifo_dest = NULL;
1060 	u16			fifo_count = 0;
1061 	struct musb_hw_ep	*hw_ep = musb->control_ep;
1062 	struct musb_qh		*qh = hw_ep->in_qh;
1063 	struct usb_ctrlrequest	*request;
1064 
1065 	switch (musb->ep0_stage) {
1066 	case MUSB_EP0_IN:
1067 		fifo_dest = urb->transfer_buffer + urb->actual_length;
1068 		fifo_count = min_t(size_t, len, urb->transfer_buffer_length -
1069 				   urb->actual_length);
1070 		if (fifo_count < len)
1071 			urb->status = -EOVERFLOW;
1072 
1073 		musb_read_fifo(hw_ep, fifo_count, fifo_dest);
1074 
1075 		urb->actual_length += fifo_count;
1076 		if (len < qh->maxpacket) {
1077 			/* always terminate on short read; it's
1078 			 * rarely reported as an error.
1079 			 */
1080 		} else if (urb->actual_length <
1081 				urb->transfer_buffer_length)
1082 			more = true;
1083 		break;
1084 	case MUSB_EP0_START:
1085 		request = (struct usb_ctrlrequest *) urb->setup_packet;
1086 
1087 		if (!request->wLength) {
1088 			dev_dbg(musb->controller, "start no-DATA\n");
1089 			break;
1090 		} else if (request->bRequestType & USB_DIR_IN) {
1091 			dev_dbg(musb->controller, "start IN-DATA\n");
1092 			musb->ep0_stage = MUSB_EP0_IN;
1093 			more = true;
1094 			break;
1095 		} else {
1096 			dev_dbg(musb->controller, "start OUT-DATA\n");
1097 			musb->ep0_stage = MUSB_EP0_OUT;
1098 			more = true;
1099 		}
1100 		/* FALLTHROUGH */
1101 	case MUSB_EP0_OUT:
1102 		fifo_count = min_t(size_t, qh->maxpacket,
1103 				   urb->transfer_buffer_length -
1104 				   urb->actual_length);
1105 		if (fifo_count) {
1106 			fifo_dest = (u8 *) (urb->transfer_buffer
1107 					+ urb->actual_length);
1108 			dev_dbg(musb->controller, "Sending %d byte%s to ep0 fifo %p\n",
1109 					fifo_count,
1110 					(fifo_count == 1) ? "" : "s",
1111 					fifo_dest);
1112 			musb_write_fifo(hw_ep, fifo_count, fifo_dest);
1113 
1114 			urb->actual_length += fifo_count;
1115 			more = true;
1116 		}
1117 		break;
1118 	default:
1119 		ERR("bogus ep0 stage %d\n", musb->ep0_stage);
1120 		break;
1121 	}
1122 
1123 	return more;
1124 }
1125 
1126 /*
1127  * Handle default endpoint interrupt as host. Only called in IRQ time
1128  * from musb_interrupt().
1129  *
1130  * called with controller irqlocked
1131  */
1132 irqreturn_t musb_h_ep0_irq(struct musb *musb)
1133 {
1134 	struct urb		*urb;
1135 	u16			csr, len;
1136 	int			status = 0;
1137 	void __iomem		*mbase = musb->mregs;
1138 	struct musb_hw_ep	*hw_ep = musb->control_ep;
1139 	void __iomem		*epio = hw_ep->regs;
1140 	struct musb_qh		*qh = hw_ep->in_qh;
1141 	bool			complete = false;
1142 	irqreturn_t		retval = IRQ_NONE;
1143 
1144 	/* ep0 only has one queue, "in" */
1145 	urb = next_urb(qh);
1146 
1147 	musb_ep_select(mbase, 0);
1148 	csr = musb_readw(epio, MUSB_CSR0);
1149 	len = (csr & MUSB_CSR0_RXPKTRDY)
1150 			? musb_readb(epio, MUSB_COUNT0)
1151 			: 0;
1152 
1153 	dev_dbg(musb->controller, "<== csr0 %04x, qh %p, count %d, urb %p, stage %d\n",
1154 		csr, qh, len, urb, musb->ep0_stage);
1155 
1156 	/* if we just did status stage, we are done */
1157 	if (MUSB_EP0_STATUS == musb->ep0_stage) {
1158 		retval = IRQ_HANDLED;
1159 		complete = true;
1160 	}
1161 
1162 	/* prepare status */
1163 	if (csr & MUSB_CSR0_H_RXSTALL) {
1164 		dev_dbg(musb->controller, "STALLING ENDPOINT\n");
1165 		status = -EPIPE;
1166 
1167 	} else if (csr & MUSB_CSR0_H_ERROR) {
1168 		dev_dbg(musb->controller, "no response, csr0 %04x\n", csr);
1169 		status = -EPROTO;
1170 
1171 	} else if (csr & MUSB_CSR0_H_NAKTIMEOUT) {
1172 		dev_dbg(musb->controller, "control NAK timeout\n");
1173 
1174 		/* NOTE:  this code path would be a good place to PAUSE a
1175 		 * control transfer, if another one is queued, so that
1176 		 * ep0 is more likely to stay busy.  That's already done
1177 		 * for bulk RX transfers.
1178 		 *
1179 		 * if (qh->ring.next != &musb->control), then
1180 		 * we have a candidate... NAKing is *NOT* an error
1181 		 */
1182 		musb_writew(epio, MUSB_CSR0, 0);
1183 		retval = IRQ_HANDLED;
1184 	}
1185 
1186 	if (status) {
1187 		dev_dbg(musb->controller, "aborting\n");
1188 		retval = IRQ_HANDLED;
1189 		if (urb)
1190 			urb->status = status;
1191 		complete = true;
1192 
1193 		/* use the proper sequence to abort the transfer */
1194 		if (csr & MUSB_CSR0_H_REQPKT) {
1195 			csr &= ~MUSB_CSR0_H_REQPKT;
1196 			musb_writew(epio, MUSB_CSR0, csr);
1197 			csr &= ~MUSB_CSR0_H_NAKTIMEOUT;
1198 			musb_writew(epio, MUSB_CSR0, csr);
1199 		} else {
1200 			musb_h_ep0_flush_fifo(hw_ep);
1201 		}
1202 
1203 		musb_writeb(epio, MUSB_NAKLIMIT0, 0);
1204 
1205 		/* clear it */
1206 		musb_writew(epio, MUSB_CSR0, 0);
1207 	}
1208 
1209 	if (unlikely(!urb)) {
1210 		/* stop endpoint since we have no place for its data, this
1211 		 * SHOULD NEVER HAPPEN! */
1212 		ERR("no URB for end 0\n");
1213 
1214 		musb_h_ep0_flush_fifo(hw_ep);
1215 		goto done;
1216 	}
1217 
1218 	if (!complete) {
1219 		/* call common logic and prepare response */
1220 		if (musb_h_ep0_continue(musb, len, urb)) {
1221 			/* more packets required */
1222 			csr = (MUSB_EP0_IN == musb->ep0_stage)
1223 				?  MUSB_CSR0_H_REQPKT : MUSB_CSR0_TXPKTRDY;
1224 		} else {
1225 			/* data transfer complete; perform status phase */
1226 			if (usb_pipeout(urb->pipe)
1227 					|| !urb->transfer_buffer_length)
1228 				csr = MUSB_CSR0_H_STATUSPKT
1229 					| MUSB_CSR0_H_REQPKT;
1230 			else
1231 				csr = MUSB_CSR0_H_STATUSPKT
1232 					| MUSB_CSR0_TXPKTRDY;
1233 
1234 			/* disable ping token in status phase */
1235 			csr |= MUSB_CSR0_H_DIS_PING;
1236 
1237 			/* flag status stage */
1238 			musb->ep0_stage = MUSB_EP0_STATUS;
1239 
1240 			dev_dbg(musb->controller, "ep0 STATUS, csr %04x\n", csr);
1241 
1242 		}
1243 		musb_writew(epio, MUSB_CSR0, csr);
1244 		retval = IRQ_HANDLED;
1245 	} else
1246 		musb->ep0_stage = MUSB_EP0_IDLE;
1247 
1248 	/* call completion handler if done */
1249 	if (complete)
1250 		musb_advance_schedule(musb, urb, hw_ep, 1);
1251 done:
1252 	return retval;
1253 }
1254 
1255 
1256 #ifdef CONFIG_USB_INVENTRA_DMA
1257 
1258 /* Host side TX (OUT) using Mentor DMA works as follows:
1259 	submit_urb ->
1260 		- if queue was empty, Program Endpoint
1261 		- ... which starts DMA to fifo in mode 1 or 0
1262 
1263 	DMA Isr (transfer complete) -> TxAvail()
1264 		- Stop DMA (~DmaEnab)	(<--- Alert ... currently happens
1265 					only in musb_cleanup_urb)
1266 		- TxPktRdy has to be set in mode 0 or for
1267 			short packets in mode 1.
1268 */
1269 
1270 #endif
1271 
1272 /* Service a Tx-Available or dma completion irq for the endpoint */
1273 void musb_host_tx(struct musb *musb, u8 epnum)
1274 {
1275 	int			pipe;
1276 	bool			done = false;
1277 	u16			tx_csr;
1278 	size_t			length = 0;
1279 	size_t			offset = 0;
1280 	struct musb_hw_ep	*hw_ep = musb->endpoints + epnum;
1281 	void __iomem		*epio = hw_ep->regs;
1282 	struct musb_qh		*qh = hw_ep->out_qh;
1283 	struct urb		*urb = next_urb(qh);
1284 	u32			status = 0;
1285 	void __iomem		*mbase = musb->mregs;
1286 	struct dma_channel	*dma;
1287 	bool			transfer_pending = false;
1288 
1289 	musb_ep_select(mbase, epnum);
1290 	tx_csr = musb_readw(epio, MUSB_TXCSR);
1291 
1292 	/* with CPPI, DMA sometimes triggers "extra" irqs */
1293 	if (!urb) {
1294 		dev_dbg(musb->controller, "extra TX%d ready, csr %04x\n", epnum, tx_csr);
1295 		return;
1296 	}
1297 
1298 	pipe = urb->pipe;
1299 	dma = is_dma_capable() ? hw_ep->tx_channel : NULL;
1300 	dev_dbg(musb->controller, "OUT/TX%d end, csr %04x%s\n", epnum, tx_csr,
1301 			dma ? ", dma" : "");
1302 
1303 	/* check for errors */
1304 	if (tx_csr & MUSB_TXCSR_H_RXSTALL) {
1305 		/* dma was disabled, fifo flushed */
1306 		dev_dbg(musb->controller, "TX end %d stall\n", epnum);
1307 
1308 		/* stall; record URB status */
1309 		status = -EPIPE;
1310 
1311 	} else if (tx_csr & MUSB_TXCSR_H_ERROR) {
1312 		/* (NON-ISO) dma was disabled, fifo flushed */
1313 		dev_dbg(musb->controller, "TX 3strikes on ep=%d\n", epnum);
1314 
1315 		status = -ETIMEDOUT;
1316 
1317 	} else if (tx_csr & MUSB_TXCSR_H_NAKTIMEOUT) {
1318 		if (USB_ENDPOINT_XFER_BULK == qh->type && qh->mux == 1
1319 				&& !list_is_singular(&musb->out_bulk)) {
1320 			dev_dbg(musb->controller,
1321 				"NAK timeout on TX%d ep\n", epnum);
1322 			musb_bulk_nak_timeout(musb, hw_ep, 0);
1323 		} else {
1324 			dev_dbg(musb->controller,
1325 				"TX end=%d device not responding\n", epnum);
1326 			/* NOTE:  this code path would be a good place to PAUSE a
1327 			 * transfer, if there's some other (nonperiodic) tx urb
1328 			 * that could use this fifo.  (dma complicates it...)
1329 			 * That's already done for bulk RX transfers.
1330 			 *
1331 			 * if (bulk && qh->ring.next != &musb->out_bulk), then
1332 			 * we have a candidate... NAKing is *NOT* an error
1333 			 */
1334 			musb_ep_select(mbase, epnum);
1335 			musb_writew(epio, MUSB_TXCSR,
1336 					MUSB_TXCSR_H_WZC_BITS
1337 					| MUSB_TXCSR_TXPKTRDY);
1338 		}
1339 			return;
1340 	}
1341 
1342 done:
1343 	if (status) {
1344 		if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1345 			dma->status = MUSB_DMA_STATUS_CORE_ABORT;
1346 			musb->dma_controller->channel_abort(dma);
1347 		}
1348 
1349 		/* do the proper sequence to abort the transfer in the
1350 		 * usb core; the dma engine should already be stopped.
1351 		 */
1352 		musb_h_tx_flush_fifo(hw_ep);
1353 		tx_csr &= ~(MUSB_TXCSR_AUTOSET
1354 				| MUSB_TXCSR_DMAENAB
1355 				| MUSB_TXCSR_H_ERROR
1356 				| MUSB_TXCSR_H_RXSTALL
1357 				| MUSB_TXCSR_H_NAKTIMEOUT
1358 				);
1359 
1360 		musb_ep_select(mbase, epnum);
1361 		musb_writew(epio, MUSB_TXCSR, tx_csr);
1362 		/* REVISIT may need to clear FLUSHFIFO ... */
1363 		musb_writew(epio, MUSB_TXCSR, tx_csr);
1364 		musb_writeb(epio, MUSB_TXINTERVAL, 0);
1365 
1366 		done = true;
1367 	}
1368 
1369 	/* second cppi case */
1370 	if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1371 		dev_dbg(musb->controller, "extra TX%d ready, csr %04x\n", epnum, tx_csr);
1372 		return;
1373 	}
1374 
1375 	if (is_dma_capable() && dma && !status) {
1376 		/*
1377 		 * DMA has completed.  But if we're using DMA mode 1 (multi
1378 		 * packet DMA), we need a terminal TXPKTRDY interrupt before
1379 		 * we can consider this transfer completed, lest we trash
1380 		 * its last packet when writing the next URB's data.  So we
1381 		 * switch back to mode 0 to get that interrupt; we'll come
1382 		 * back here once it happens.
1383 		 */
1384 		if (tx_csr & MUSB_TXCSR_DMAMODE) {
1385 			/*
1386 			 * We shouldn't clear DMAMODE with DMAENAB set; so
1387 			 * clear them in a safe order.  That should be OK
1388 			 * once TXPKTRDY has been set (and I've never seen
1389 			 * it being 0 at this moment -- DMA interrupt latency
1390 			 * is significant) but if it hasn't been then we have
1391 			 * no choice but to stop being polite and ignore the
1392 			 * programmer's guide... :-)
1393 			 *
1394 			 * Note that we must write TXCSR with TXPKTRDY cleared
1395 			 * in order not to re-trigger the packet send (this bit
1396 			 * can't be cleared by CPU), and there's another caveat:
1397 			 * TXPKTRDY may be set shortly and then cleared in the
1398 			 * double-buffered FIFO mode, so we do an extra TXCSR
1399 			 * read for debouncing...
1400 			 */
1401 			tx_csr &= musb_readw(epio, MUSB_TXCSR);
1402 			if (tx_csr & MUSB_TXCSR_TXPKTRDY) {
1403 				tx_csr &= ~(MUSB_TXCSR_DMAENAB |
1404 					    MUSB_TXCSR_TXPKTRDY);
1405 				musb_writew(epio, MUSB_TXCSR,
1406 					    tx_csr | MUSB_TXCSR_H_WZC_BITS);
1407 			}
1408 			tx_csr &= ~(MUSB_TXCSR_DMAMODE |
1409 				    MUSB_TXCSR_TXPKTRDY);
1410 			musb_writew(epio, MUSB_TXCSR,
1411 				    tx_csr | MUSB_TXCSR_H_WZC_BITS);
1412 
1413 			/*
1414 			 * There is no guarantee that we'll get an interrupt
1415 			 * after clearing DMAMODE as we might have done this
1416 			 * too late (after TXPKTRDY was cleared by controller).
1417 			 * Re-read TXCSR as we have spoiled its previous value.
1418 			 */
1419 			tx_csr = musb_readw(epio, MUSB_TXCSR);
1420 		}
1421 
1422 		/*
1423 		 * We may get here from a DMA completion or TXPKTRDY interrupt.
1424 		 * In any case, we must check the FIFO status here and bail out
1425 		 * only if the FIFO still has data -- that should prevent the
1426 		 * "missed" TXPKTRDY interrupts and deal with double-buffered
1427 		 * FIFO mode too...
1428 		 */
1429 		if (tx_csr & (MUSB_TXCSR_FIFONOTEMPTY | MUSB_TXCSR_TXPKTRDY)) {
1430 			dev_dbg(musb->controller, "DMA complete but packet still in FIFO, "
1431 			    "CSR %04x\n", tx_csr);
1432 			return;
1433 		}
1434 	}
1435 
1436 	if (!status || dma || usb_pipeisoc(pipe)) {
1437 		if (dma)
1438 			length = dma->actual_len;
1439 		else
1440 			length = qh->segsize;
1441 		qh->offset += length;
1442 
1443 		if (usb_pipeisoc(pipe)) {
1444 			struct usb_iso_packet_descriptor	*d;
1445 
1446 			d = urb->iso_frame_desc + qh->iso_idx;
1447 			d->actual_length = length;
1448 			d->status = status;
1449 			if (++qh->iso_idx >= urb->number_of_packets) {
1450 				done = true;
1451 			} else {
1452 				d++;
1453 				offset = d->offset;
1454 				length = d->length;
1455 			}
1456 		} else if (dma && urb->transfer_buffer_length == qh->offset) {
1457 			done = true;
1458 		} else {
1459 			/* see if we need to send more data, or ZLP */
1460 			if (qh->segsize < qh->maxpacket)
1461 				done = true;
1462 			else if (qh->offset == urb->transfer_buffer_length
1463 					&& !(urb->transfer_flags
1464 						& URB_ZERO_PACKET))
1465 				done = true;
1466 			if (!done) {
1467 				offset = qh->offset;
1468 				length = urb->transfer_buffer_length - offset;
1469 				transfer_pending = true;
1470 			}
1471 		}
1472 	}
1473 
1474 	/* urb->status != -EINPROGRESS means request has been faulted,
1475 	 * so we must abort this transfer after cleanup
1476 	 */
1477 	if (urb->status != -EINPROGRESS) {
1478 		done = true;
1479 		if (status == 0)
1480 			status = urb->status;
1481 	}
1482 
1483 	if (done) {
1484 		/* set status */
1485 		urb->status = status;
1486 		urb->actual_length = qh->offset;
1487 		musb_advance_schedule(musb, urb, hw_ep, USB_DIR_OUT);
1488 		return;
1489 	} else if ((usb_pipeisoc(pipe) || transfer_pending) && dma) {
1490 		if (musb_tx_dma_program(musb->dma_controller, hw_ep, qh, urb,
1491 				offset, length)) {
1492 			if (is_cppi_enabled(musb) || tusb_dma_omap(musb))
1493 				musb_h_tx_dma_start(hw_ep);
1494 			return;
1495 		}
1496 	} else	if (tx_csr & MUSB_TXCSR_DMAENAB) {
1497 		dev_dbg(musb->controller, "not complete, but DMA enabled?\n");
1498 		return;
1499 	}
1500 
1501 	/*
1502 	 * PIO: start next packet in this URB.
1503 	 *
1504 	 * REVISIT: some docs say that when hw_ep->tx_double_buffered,
1505 	 * (and presumably, FIFO is not half-full) we should write *two*
1506 	 * packets before updating TXCSR; other docs disagree...
1507 	 */
1508 	if (length > qh->maxpacket)
1509 		length = qh->maxpacket;
1510 	/* Unmap the buffer so that CPU can use it */
1511 	usb_hcd_unmap_urb_for_dma(musb->hcd, urb);
1512 
1513 	/*
1514 	 * We need to map sg if the transfer_buffer is
1515 	 * NULL.
1516 	 */
1517 	if (!urb->transfer_buffer)
1518 		qh->use_sg = true;
1519 
1520 	if (qh->use_sg) {
1521 		/* sg_miter_start is already done in musb_ep_program */
1522 		if (!sg_miter_next(&qh->sg_miter)) {
1523 			dev_err(musb->controller, "error: sg list empty\n");
1524 			sg_miter_stop(&qh->sg_miter);
1525 			status = -EINVAL;
1526 			goto done;
1527 		}
1528 		urb->transfer_buffer = qh->sg_miter.addr;
1529 		length = min_t(u32, length, qh->sg_miter.length);
1530 		musb_write_fifo(hw_ep, length, urb->transfer_buffer);
1531 		qh->sg_miter.consumed = length;
1532 		sg_miter_stop(&qh->sg_miter);
1533 	} else {
1534 		musb_write_fifo(hw_ep, length, urb->transfer_buffer + offset);
1535 	}
1536 
1537 	qh->segsize = length;
1538 
1539 	if (qh->use_sg) {
1540 		if (offset + length >= urb->transfer_buffer_length)
1541 			qh->use_sg = false;
1542 	}
1543 
1544 	musb_ep_select(mbase, epnum);
1545 	musb_writew(epio, MUSB_TXCSR,
1546 			MUSB_TXCSR_H_WZC_BITS | MUSB_TXCSR_TXPKTRDY);
1547 }
1548 
1549 #ifdef CONFIG_USB_TI_CPPI41_DMA
1550 /* Seems to set up ISO for cppi41 and not advance len. See commit c57c41d */
1551 static int musb_rx_dma_iso_cppi41(struct dma_controller *dma,
1552 				  struct musb_hw_ep *hw_ep,
1553 				  struct musb_qh *qh,
1554 				  struct urb *urb,
1555 				  size_t len)
1556 {
1557 	struct dma_channel *channel = hw_ep->rx_channel;
1558 	void __iomem *epio = hw_ep->regs;
1559 	dma_addr_t *buf;
1560 	u32 length, res;
1561 	u16 val;
1562 
1563 	buf = (void *)urb->iso_frame_desc[qh->iso_idx].offset +
1564 		(u32)urb->transfer_dma;
1565 
1566 	length = urb->iso_frame_desc[qh->iso_idx].length;
1567 
1568 	val = musb_readw(epio, MUSB_RXCSR);
1569 	val |= MUSB_RXCSR_DMAENAB;
1570 	musb_writew(hw_ep->regs, MUSB_RXCSR, val);
1571 
1572 	res = dma->channel_program(channel, qh->maxpacket, 0,
1573 				   (u32)buf, length);
1574 
1575 	return res;
1576 }
1577 #else
1578 static inline int musb_rx_dma_iso_cppi41(struct dma_controller *dma,
1579 					 struct musb_hw_ep *hw_ep,
1580 					 struct musb_qh *qh,
1581 					 struct urb *urb,
1582 					 size_t len)
1583 {
1584 	return false;
1585 }
1586 #endif
1587 
1588 #if defined(CONFIG_USB_INVENTRA_DMA) || defined(CONFIG_USB_UX500_DMA) || \
1589 	defined(CONFIG_USB_TI_CPPI41_DMA)
1590 /* Host side RX (IN) using Mentor DMA works as follows:
1591 	submit_urb ->
1592 		- if queue was empty, ProgramEndpoint
1593 		- first IN token is sent out (by setting ReqPkt)
1594 	LinuxIsr -> RxReady()
1595 	/\	=> first packet is received
1596 	|	- Set in mode 0 (DmaEnab, ~ReqPkt)
1597 	|		-> DMA Isr (transfer complete) -> RxReady()
1598 	|		    - Ack receive (~RxPktRdy), turn off DMA (~DmaEnab)
1599 	|		    - if urb not complete, send next IN token (ReqPkt)
1600 	|			   |		else complete urb.
1601 	|			   |
1602 	---------------------------
1603  *
1604  * Nuances of mode 1:
1605  *	For short packets, no ack (+RxPktRdy) is sent automatically
1606  *	(even if AutoClear is ON)
1607  *	For full packets, ack (~RxPktRdy) and next IN token (+ReqPkt) is sent
1608  *	automatically => major problem, as collecting the next packet becomes
1609  *	difficult. Hence mode 1 is not used.
1610  *
1611  * REVISIT
1612  *	All we care about at this driver level is that
1613  *       (a) all URBs terminate with REQPKT cleared and fifo(s) empty;
1614  *       (b) termination conditions are: short RX, or buffer full;
1615  *       (c) fault modes include
1616  *           - iff URB_SHORT_NOT_OK, short RX status is -EREMOTEIO.
1617  *             (and that endpoint's dma queue stops immediately)
1618  *           - overflow (full, PLUS more bytes in the terminal packet)
1619  *
1620  *	So for example, usb-storage sets URB_SHORT_NOT_OK, and would
1621  *	thus be a great candidate for using mode 1 ... for all but the
1622  *	last packet of one URB's transfer.
1623  */
1624 static int musb_rx_dma_inventra_cppi41(struct dma_controller *dma,
1625 				       struct musb_hw_ep *hw_ep,
1626 				       struct musb_qh *qh,
1627 				       struct urb *urb,
1628 				       size_t len)
1629 {
1630 	struct dma_channel *channel = hw_ep->rx_channel;
1631 	void __iomem *epio = hw_ep->regs;
1632 	u16 val;
1633 	int pipe;
1634 	bool done;
1635 
1636 	pipe = urb->pipe;
1637 
1638 	if (usb_pipeisoc(pipe)) {
1639 		struct usb_iso_packet_descriptor *d;
1640 
1641 		d = urb->iso_frame_desc + qh->iso_idx;
1642 		d->actual_length = len;
1643 
1644 		/* even if there was an error, we did the dma
1645 		 * for iso_frame_desc->length
1646 		 */
1647 		if (d->status != -EILSEQ && d->status != -EOVERFLOW)
1648 			d->status = 0;
1649 
1650 		if (++qh->iso_idx >= urb->number_of_packets) {
1651 			done = true;
1652 		} else {
1653 			/* REVISIT: Why ignore return value here? */
1654 			if (musb_dma_cppi41(hw_ep->musb))
1655 				done = musb_rx_dma_iso_cppi41(dma, hw_ep, qh,
1656 							      urb, len);
1657 			done = false;
1658 		}
1659 
1660 	} else  {
1661 		/* done if urb buffer is full or short packet is recd */
1662 		done = (urb->actual_length + len >=
1663 			urb->transfer_buffer_length
1664 			|| channel->actual_len < qh->maxpacket
1665 			|| channel->rx_packet_done);
1666 	}
1667 
1668 	/* send IN token for next packet, without AUTOREQ */
1669 	if (!done) {
1670 		val = musb_readw(epio, MUSB_RXCSR);
1671 		val |= MUSB_RXCSR_H_REQPKT;
1672 		musb_writew(epio, MUSB_RXCSR, MUSB_RXCSR_H_WZC_BITS | val);
1673 	}
1674 
1675 	return done;
1676 }
1677 
1678 /* Disadvantage of using mode 1:
1679  *	It's basically usable only for mass storage class; essentially all
1680  *	other protocols also terminate transfers on short packets.
1681  *
1682  * Details:
1683  *	An extra IN token is sent at the end of the transfer (due to AUTOREQ)
1684  *	If you try to use mode 1 for (transfer_buffer_length - 512), and try
1685  *	to use the extra IN token to grab the last packet using mode 0, then
1686  *	the problem is that you cannot be sure when the device will send the
1687  *	last packet and RxPktRdy set. Sometimes the packet is recd too soon
1688  *	such that it gets lost when RxCSR is re-set at the end of the mode 1
1689  *	transfer, while sometimes it is recd just a little late so that if you
1690  *	try to configure for mode 0 soon after the mode 1 transfer is
1691  *	completed, you will find rxcount 0. Okay, so you might think why not
1692  *	wait for an interrupt when the pkt is recd. Well, you won't get any!
1693  */
1694 static int musb_rx_dma_in_inventra_cppi41(struct dma_controller *dma,
1695 					  struct musb_hw_ep *hw_ep,
1696 					  struct musb_qh *qh,
1697 					  struct urb *urb,
1698 					  size_t len,
1699 					  u8 iso_err)
1700 {
1701 	struct musb *musb = hw_ep->musb;
1702 	void __iomem *epio = hw_ep->regs;
1703 	struct dma_channel *channel = hw_ep->rx_channel;
1704 	u16 rx_count, val;
1705 	int length, pipe, done;
1706 	dma_addr_t buf;
1707 
1708 	rx_count = musb_readw(epio, MUSB_RXCOUNT);
1709 	pipe = urb->pipe;
1710 
1711 	if (usb_pipeisoc(pipe)) {
1712 		int d_status = 0;
1713 		struct usb_iso_packet_descriptor *d;
1714 
1715 		d = urb->iso_frame_desc + qh->iso_idx;
1716 
1717 		if (iso_err) {
1718 			d_status = -EILSEQ;
1719 			urb->error_count++;
1720 		}
1721 		if (rx_count > d->length) {
1722 			if (d_status == 0) {
1723 				d_status = -EOVERFLOW;
1724 				urb->error_count++;
1725 			}
1726 			dev_dbg(musb->controller, "** OVERFLOW %d into %d\n",
1727 				rx_count, d->length);
1728 
1729 			length = d->length;
1730 		} else
1731 			length = rx_count;
1732 		d->status = d_status;
1733 		buf = urb->transfer_dma + d->offset;
1734 	} else {
1735 		length = rx_count;
1736 		buf = urb->transfer_dma + urb->actual_length;
1737 	}
1738 
1739 	channel->desired_mode = 0;
1740 #ifdef USE_MODE1
1741 	/* because of the issue below, mode 1 will
1742 	 * only rarely behave with correct semantics.
1743 	 */
1744 	if ((urb->transfer_flags & URB_SHORT_NOT_OK)
1745 	    && (urb->transfer_buffer_length - urb->actual_length)
1746 	    > qh->maxpacket)
1747 		channel->desired_mode = 1;
1748 	if (rx_count < hw_ep->max_packet_sz_rx) {
1749 		length = rx_count;
1750 		channel->desired_mode = 0;
1751 	} else {
1752 		length = urb->transfer_buffer_length;
1753 	}
1754 #endif
1755 
1756 	/* See comments above on disadvantages of using mode 1 */
1757 	val = musb_readw(epio, MUSB_RXCSR);
1758 	val &= ~MUSB_RXCSR_H_REQPKT;
1759 
1760 	if (channel->desired_mode == 0)
1761 		val &= ~MUSB_RXCSR_H_AUTOREQ;
1762 	else
1763 		val |= MUSB_RXCSR_H_AUTOREQ;
1764 	val |= MUSB_RXCSR_DMAENAB;
1765 
1766 	/* autoclear shouldn't be set in high bandwidth */
1767 	if (qh->hb_mult == 1)
1768 		val |= MUSB_RXCSR_AUTOCLEAR;
1769 
1770 	musb_writew(epio, MUSB_RXCSR, MUSB_RXCSR_H_WZC_BITS | val);
1771 
1772 	/* REVISIT if when actual_length != 0,
1773 	 * transfer_buffer_length needs to be
1774 	 * adjusted first...
1775 	 */
1776 	done = dma->channel_program(channel, qh->maxpacket,
1777 				   channel->desired_mode,
1778 				   buf, length);
1779 
1780 	if (!done) {
1781 		dma->channel_release(channel);
1782 		hw_ep->rx_channel = NULL;
1783 		channel = NULL;
1784 		val = musb_readw(epio, MUSB_RXCSR);
1785 		val &= ~(MUSB_RXCSR_DMAENAB
1786 			 | MUSB_RXCSR_H_AUTOREQ
1787 			 | MUSB_RXCSR_AUTOCLEAR);
1788 		musb_writew(epio, MUSB_RXCSR, val);
1789 	}
1790 
1791 	return done;
1792 }
1793 #else
1794 static inline int musb_rx_dma_inventra_cppi41(struct dma_controller *dma,
1795 					      struct musb_hw_ep *hw_ep,
1796 					      struct musb_qh *qh,
1797 					      struct urb *urb,
1798 					      size_t len)
1799 {
1800 	return false;
1801 }
1802 
1803 static inline int musb_rx_dma_in_inventra_cppi41(struct dma_controller *dma,
1804 						 struct musb_hw_ep *hw_ep,
1805 						 struct musb_qh *qh,
1806 						 struct urb *urb,
1807 						 size_t len,
1808 						 u8 iso_err)
1809 {
1810 	return false;
1811 }
1812 #endif
1813 
1814 /*
1815  * Service an RX interrupt for the given IN endpoint; docs cover bulk, iso,
1816  * and high-bandwidth IN transfer cases.
1817  */
1818 void musb_host_rx(struct musb *musb, u8 epnum)
1819 {
1820 	struct urb		*urb;
1821 	struct musb_hw_ep	*hw_ep = musb->endpoints + epnum;
1822 	struct dma_controller	*c = musb->dma_controller;
1823 	void __iomem		*epio = hw_ep->regs;
1824 	struct musb_qh		*qh = hw_ep->in_qh;
1825 	size_t			xfer_len;
1826 	void __iomem		*mbase = musb->mregs;
1827 	int			pipe;
1828 	u16			rx_csr, val;
1829 	bool			iso_err = false;
1830 	bool			done = false;
1831 	u32			status;
1832 	struct dma_channel	*dma;
1833 	unsigned int sg_flags = SG_MITER_ATOMIC | SG_MITER_TO_SG;
1834 
1835 	musb_ep_select(mbase, epnum);
1836 
1837 	urb = next_urb(qh);
1838 	dma = is_dma_capable() ? hw_ep->rx_channel : NULL;
1839 	status = 0;
1840 	xfer_len = 0;
1841 
1842 	rx_csr = musb_readw(epio, MUSB_RXCSR);
1843 	val = rx_csr;
1844 
1845 	if (unlikely(!urb)) {
1846 		/* REVISIT -- THIS SHOULD NEVER HAPPEN ... but, at least
1847 		 * usbtest #11 (unlinks) triggers it regularly, sometimes
1848 		 * with fifo full.  (Only with DMA??)
1849 		 */
1850 		dev_dbg(musb->controller, "BOGUS RX%d ready, csr %04x, count %d\n", epnum, val,
1851 			musb_readw(epio, MUSB_RXCOUNT));
1852 		musb_h_flush_rxfifo(hw_ep, MUSB_RXCSR_CLRDATATOG);
1853 		return;
1854 	}
1855 
1856 	pipe = urb->pipe;
1857 
1858 	dev_dbg(musb->controller, "<== hw %d rxcsr %04x, urb actual %d (+dma %zu)\n",
1859 		epnum, rx_csr, urb->actual_length,
1860 		dma ? dma->actual_len : 0);
1861 
1862 	/* check for errors, concurrent stall & unlink is not really
1863 	 * handled yet! */
1864 	if (rx_csr & MUSB_RXCSR_H_RXSTALL) {
1865 		dev_dbg(musb->controller, "RX end %d STALL\n", epnum);
1866 
1867 		/* stall; record URB status */
1868 		status = -EPIPE;
1869 
1870 	} else if (rx_csr & MUSB_RXCSR_H_ERROR) {
1871 		dev_dbg(musb->controller, "end %d RX proto error\n", epnum);
1872 
1873 		status = -EPROTO;
1874 		musb_writeb(epio, MUSB_RXINTERVAL, 0);
1875 
1876 		rx_csr &= ~MUSB_RXCSR_H_ERROR;
1877 		musb_writew(epio, MUSB_RXCSR, rx_csr);
1878 
1879 	} else if (rx_csr & MUSB_RXCSR_DATAERROR) {
1880 
1881 		if (USB_ENDPOINT_XFER_ISOC != qh->type) {
1882 			dev_dbg(musb->controller, "RX end %d NAK timeout\n", epnum);
1883 
1884 			/* NOTE: NAKing is *NOT* an error, so we want to
1885 			 * continue.  Except ... if there's a request for
1886 			 * another QH, use that instead of starving it.
1887 			 *
1888 			 * Devices like Ethernet and serial adapters keep
1889 			 * reads posted at all times, which will starve
1890 			 * other devices without this logic.
1891 			 */
1892 			if (usb_pipebulk(urb->pipe)
1893 					&& qh->mux == 1
1894 					&& !list_is_singular(&musb->in_bulk)) {
1895 				musb_bulk_nak_timeout(musb, hw_ep, 1);
1896 				return;
1897 			}
1898 			musb_ep_select(mbase, epnum);
1899 			rx_csr |= MUSB_RXCSR_H_WZC_BITS;
1900 			rx_csr &= ~MUSB_RXCSR_DATAERROR;
1901 			musb_writew(epio, MUSB_RXCSR, rx_csr);
1902 
1903 			goto finish;
1904 		} else {
1905 			dev_dbg(musb->controller, "RX end %d ISO data error\n", epnum);
1906 			/* packet error reported later */
1907 			iso_err = true;
1908 		}
1909 	} else if (rx_csr & MUSB_RXCSR_INCOMPRX) {
1910 		dev_dbg(musb->controller, "end %d high bandwidth incomplete ISO packet RX\n",
1911 				epnum);
1912 		status = -EPROTO;
1913 	}
1914 
1915 	/* faults abort the transfer */
1916 	if (status) {
1917 		/* clean up dma and collect transfer count */
1918 		if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1919 			dma->status = MUSB_DMA_STATUS_CORE_ABORT;
1920 			musb->dma_controller->channel_abort(dma);
1921 			xfer_len = dma->actual_len;
1922 		}
1923 		musb_h_flush_rxfifo(hw_ep, MUSB_RXCSR_CLRDATATOG);
1924 		musb_writeb(epio, MUSB_RXINTERVAL, 0);
1925 		done = true;
1926 		goto finish;
1927 	}
1928 
1929 	if (unlikely(dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY)) {
1930 		/* SHOULD NEVER HAPPEN ... but at least DaVinci has done it */
1931 		ERR("RX%d dma busy, csr %04x\n", epnum, rx_csr);
1932 		goto finish;
1933 	}
1934 
1935 	/* thorough shutdown for now ... given more precise fault handling
1936 	 * and better queueing support, we might keep a DMA pipeline going
1937 	 * while processing this irq for earlier completions.
1938 	 */
1939 
1940 	/* FIXME this is _way_ too much in-line logic for Mentor DMA */
1941 	if (!musb_dma_inventra(musb) && !musb_dma_ux500(musb) &&
1942 	    (rx_csr & MUSB_RXCSR_H_REQPKT)) {
1943 		/* REVISIT this happened for a while on some short reads...
1944 		 * the cleanup still needs investigation... looks bad...
1945 		 * and also duplicates dma cleanup code above ... plus,
1946 		 * shouldn't this be the "half full" double buffer case?
1947 		 */
1948 		if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1949 			dma->status = MUSB_DMA_STATUS_CORE_ABORT;
1950 			musb->dma_controller->channel_abort(dma);
1951 			xfer_len = dma->actual_len;
1952 			done = true;
1953 		}
1954 
1955 		dev_dbg(musb->controller, "RXCSR%d %04x, reqpkt, len %zu%s\n", epnum, rx_csr,
1956 				xfer_len, dma ? ", dma" : "");
1957 		rx_csr &= ~MUSB_RXCSR_H_REQPKT;
1958 
1959 		musb_ep_select(mbase, epnum);
1960 		musb_writew(epio, MUSB_RXCSR,
1961 				MUSB_RXCSR_H_WZC_BITS | rx_csr);
1962 	}
1963 
1964 	if (dma && (rx_csr & MUSB_RXCSR_DMAENAB)) {
1965 		xfer_len = dma->actual_len;
1966 
1967 		val &= ~(MUSB_RXCSR_DMAENAB
1968 			| MUSB_RXCSR_H_AUTOREQ
1969 			| MUSB_RXCSR_AUTOCLEAR
1970 			| MUSB_RXCSR_RXPKTRDY);
1971 		musb_writew(hw_ep->regs, MUSB_RXCSR, val);
1972 
1973 		if (musb_dma_inventra(musb) || musb_dma_ux500(musb) ||
1974 		    musb_dma_cppi41(musb)) {
1975 			    done = musb_rx_dma_inventra_cppi41(c, hw_ep, qh, urb, xfer_len);
1976 			    dev_dbg(hw_ep->musb->controller,
1977 				    "ep %d dma %s, rxcsr %04x, rxcount %d\n",
1978 				    epnum, done ? "off" : "reset",
1979 				    musb_readw(epio, MUSB_RXCSR),
1980 				    musb_readw(epio, MUSB_RXCOUNT));
1981 		} else {
1982 			done = true;
1983 		}
1984 
1985 	} else if (urb->status == -EINPROGRESS) {
1986 		/* if no errors, be sure a packet is ready for unloading */
1987 		if (unlikely(!(rx_csr & MUSB_RXCSR_RXPKTRDY))) {
1988 			status = -EPROTO;
1989 			ERR("Rx interrupt with no errors or packet!\n");
1990 
1991 			/* FIXME this is another "SHOULD NEVER HAPPEN" */
1992 
1993 /* SCRUB (RX) */
1994 			/* do the proper sequence to abort the transfer */
1995 			musb_ep_select(mbase, epnum);
1996 			val &= ~MUSB_RXCSR_H_REQPKT;
1997 			musb_writew(epio, MUSB_RXCSR, val);
1998 			goto finish;
1999 		}
2000 
2001 		/* we are expecting IN packets */
2002 		if ((musb_dma_inventra(musb) || musb_dma_ux500(musb) ||
2003 		    musb_dma_cppi41(musb)) && dma) {
2004 			dev_dbg(hw_ep->musb->controller,
2005 				"RX%d count %d, buffer 0x%llx len %d/%d\n",
2006 				epnum, musb_readw(epio, MUSB_RXCOUNT),
2007 				(unsigned long long) urb->transfer_dma
2008 				+ urb->actual_length,
2009 				qh->offset,
2010 				urb->transfer_buffer_length);
2011 
2012 			if (musb_rx_dma_in_inventra_cppi41(c, hw_ep, qh, urb,
2013 							   xfer_len, iso_err))
2014 				goto finish;
2015 			else
2016 				dev_err(musb->controller, "error: rx_dma failed\n");
2017 		}
2018 
2019 		if (!dma) {
2020 			unsigned int received_len;
2021 
2022 			/* Unmap the buffer so that CPU can use it */
2023 			usb_hcd_unmap_urb_for_dma(musb->hcd, urb);
2024 
2025 			/*
2026 			 * We need to map sg if the transfer_buffer is
2027 			 * NULL.
2028 			 */
2029 			if (!urb->transfer_buffer) {
2030 				qh->use_sg = true;
2031 				sg_miter_start(&qh->sg_miter, urb->sg, 1,
2032 						sg_flags);
2033 			}
2034 
2035 			if (qh->use_sg) {
2036 				if (!sg_miter_next(&qh->sg_miter)) {
2037 					dev_err(musb->controller, "error: sg list empty\n");
2038 					sg_miter_stop(&qh->sg_miter);
2039 					status = -EINVAL;
2040 					done = true;
2041 					goto finish;
2042 				}
2043 				urb->transfer_buffer = qh->sg_miter.addr;
2044 				received_len = urb->actual_length;
2045 				qh->offset = 0x0;
2046 				done = musb_host_packet_rx(musb, urb, epnum,
2047 						iso_err);
2048 				/* Calculate the number of bytes received */
2049 				received_len = urb->actual_length -
2050 					received_len;
2051 				qh->sg_miter.consumed = received_len;
2052 				sg_miter_stop(&qh->sg_miter);
2053 			} else {
2054 				done = musb_host_packet_rx(musb, urb,
2055 						epnum, iso_err);
2056 			}
2057 			dev_dbg(musb->controller, "read %spacket\n", done ? "last " : "");
2058 		}
2059 	}
2060 
2061 finish:
2062 	urb->actual_length += xfer_len;
2063 	qh->offset += xfer_len;
2064 	if (done) {
2065 		if (qh->use_sg)
2066 			qh->use_sg = false;
2067 
2068 		if (urb->status == -EINPROGRESS)
2069 			urb->status = status;
2070 		musb_advance_schedule(musb, urb, hw_ep, USB_DIR_IN);
2071 	}
2072 }
2073 
2074 /* schedule nodes correspond to peripheral endpoints, like an OHCI QH.
2075  * the software schedule associates multiple such nodes with a given
2076  * host side hardware endpoint + direction; scheduling may activate
2077  * that hardware endpoint.
2078  */
2079 static int musb_schedule(
2080 	struct musb		*musb,
2081 	struct musb_qh		*qh,
2082 	int			is_in)
2083 {
2084 	int			idle = 0;
2085 	int			best_diff;
2086 	int			best_end, epnum;
2087 	struct musb_hw_ep	*hw_ep = NULL;
2088 	struct list_head	*head = NULL;
2089 	u8			toggle;
2090 	u8			txtype;
2091 	struct urb		*urb = next_urb(qh);
2092 
2093 	/* use fixed hardware for control and bulk */
2094 	if (qh->type == USB_ENDPOINT_XFER_CONTROL) {
2095 		head = &musb->control;
2096 		hw_ep = musb->control_ep;
2097 		goto success;
2098 	}
2099 
2100 	/* else, periodic transfers get muxed to other endpoints */
2101 
2102 	/*
2103 	 * We know this qh hasn't been scheduled, so all we need to do
2104 	 * is choose which hardware endpoint to put it on ...
2105 	 *
2106 	 * REVISIT what we really want here is a regular schedule tree
2107 	 * like e.g. OHCI uses.
2108 	 */
2109 	best_diff = 4096;
2110 	best_end = -1;
2111 
2112 	for (epnum = 1, hw_ep = musb->endpoints + 1;
2113 			epnum < musb->nr_endpoints;
2114 			epnum++, hw_ep++) {
2115 		int	diff;
2116 
2117 		if (musb_ep_get_qh(hw_ep, is_in) != NULL)
2118 			continue;
2119 
2120 		if (hw_ep == musb->bulk_ep)
2121 			continue;
2122 
2123 		if (is_in)
2124 			diff = hw_ep->max_packet_sz_rx;
2125 		else
2126 			diff = hw_ep->max_packet_sz_tx;
2127 		diff -= (qh->maxpacket * qh->hb_mult);
2128 
2129 		if (diff >= 0 && best_diff > diff) {
2130 
2131 			/*
2132 			 * Mentor controller has a bug in that if we schedule
2133 			 * a BULK Tx transfer on an endpoint that had earlier
2134 			 * handled ISOC then the BULK transfer has to start on
2135 			 * a zero toggle.  If the BULK transfer starts on a 1
2136 			 * toggle then this transfer will fail as the mentor
2137 			 * controller starts the Bulk transfer on a 0 toggle
2138 			 * irrespective of the programming of the toggle bits
2139 			 * in the TXCSR register.  Check for this condition
2140 			 * while allocating the EP for a Tx Bulk transfer.  If
2141 			 * so skip this EP.
2142 			 */
2143 			hw_ep = musb->endpoints + epnum;
2144 			toggle = usb_gettoggle(urb->dev, qh->epnum, !is_in);
2145 			txtype = (musb_readb(hw_ep->regs, MUSB_TXTYPE)
2146 					>> 4) & 0x3;
2147 			if (!is_in && (qh->type == USB_ENDPOINT_XFER_BULK) &&
2148 				toggle && (txtype == USB_ENDPOINT_XFER_ISOC))
2149 				continue;
2150 
2151 			best_diff = diff;
2152 			best_end = epnum;
2153 		}
2154 	}
2155 	/* use bulk reserved ep1 if no other ep is free */
2156 	if (best_end < 0 && qh->type == USB_ENDPOINT_XFER_BULK) {
2157 		hw_ep = musb->bulk_ep;
2158 		if (is_in)
2159 			head = &musb->in_bulk;
2160 		else
2161 			head = &musb->out_bulk;
2162 
2163 		/* Enable bulk RX/TX NAK timeout scheme when bulk requests are
2164 		 * multiplexed. This scheme does not work in high speed to full
2165 		 * speed scenario as NAK interrupts are not coming from a
2166 		 * full speed device connected to a high speed device.
2167 		 * NAK timeout interval is 8 (128 uframe or 16ms) for HS and
2168 		 * 4 (8 frame or 8ms) for FS device.
2169 		 */
2170 		if (qh->dev)
2171 			qh->intv_reg =
2172 				(USB_SPEED_HIGH == qh->dev->speed) ? 8 : 4;
2173 		goto success;
2174 	} else if (best_end < 0) {
2175 		return -ENOSPC;
2176 	}
2177 
2178 	idle = 1;
2179 	qh->mux = 0;
2180 	hw_ep = musb->endpoints + best_end;
2181 	dev_dbg(musb->controller, "qh %p periodic slot %d\n", qh, best_end);
2182 success:
2183 	if (head) {
2184 		idle = list_empty(head);
2185 		list_add_tail(&qh->ring, head);
2186 		qh->mux = 1;
2187 	}
2188 	qh->hw_ep = hw_ep;
2189 	qh->hep->hcpriv = qh;
2190 	if (idle)
2191 		musb_start_urb(musb, is_in, qh);
2192 	return 0;
2193 }
2194 
2195 static int musb_urb_enqueue(
2196 	struct usb_hcd			*hcd,
2197 	struct urb			*urb,
2198 	gfp_t				mem_flags)
2199 {
2200 	unsigned long			flags;
2201 	struct musb			*musb = hcd_to_musb(hcd);
2202 	struct usb_host_endpoint	*hep = urb->ep;
2203 	struct musb_qh			*qh;
2204 	struct usb_endpoint_descriptor	*epd = &hep->desc;
2205 	int				ret;
2206 	unsigned			type_reg;
2207 	unsigned			interval;
2208 
2209 	/* host role must be active */
2210 	if (!is_host_active(musb) || !musb->is_active)
2211 		return -ENODEV;
2212 
2213 	spin_lock_irqsave(&musb->lock, flags);
2214 	ret = usb_hcd_link_urb_to_ep(hcd, urb);
2215 	qh = ret ? NULL : hep->hcpriv;
2216 	if (qh)
2217 		urb->hcpriv = qh;
2218 	spin_unlock_irqrestore(&musb->lock, flags);
2219 
2220 	/* DMA mapping was already done, if needed, and this urb is on
2221 	 * hep->urb_list now ... so we're done, unless hep wasn't yet
2222 	 * scheduled onto a live qh.
2223 	 *
2224 	 * REVISIT best to keep hep->hcpriv valid until the endpoint gets
2225 	 * disabled, testing for empty qh->ring and avoiding qh setup costs
2226 	 * except for the first urb queued after a config change.
2227 	 */
2228 	if (qh || ret)
2229 		return ret;
2230 
2231 	/* Allocate and initialize qh, minimizing the work done each time
2232 	 * hw_ep gets reprogrammed, or with irqs blocked.  Then schedule it.
2233 	 *
2234 	 * REVISIT consider a dedicated qh kmem_cache, so it's harder
2235 	 * for bugs in other kernel code to break this driver...
2236 	 */
2237 	qh = kzalloc(sizeof *qh, mem_flags);
2238 	if (!qh) {
2239 		spin_lock_irqsave(&musb->lock, flags);
2240 		usb_hcd_unlink_urb_from_ep(hcd, urb);
2241 		spin_unlock_irqrestore(&musb->lock, flags);
2242 		return -ENOMEM;
2243 	}
2244 
2245 	qh->hep = hep;
2246 	qh->dev = urb->dev;
2247 	INIT_LIST_HEAD(&qh->ring);
2248 	qh->is_ready = 1;
2249 
2250 	qh->maxpacket = usb_endpoint_maxp(epd);
2251 	qh->type = usb_endpoint_type(epd);
2252 
2253 	/* Bits 11 & 12 of wMaxPacketSize encode high bandwidth multiplier.
2254 	 * Some musb cores don't support high bandwidth ISO transfers; and
2255 	 * we don't (yet!) support high bandwidth interrupt transfers.
2256 	 */
2257 	qh->hb_mult = 1 + ((qh->maxpacket >> 11) & 0x03);
2258 	if (qh->hb_mult > 1) {
2259 		int ok = (qh->type == USB_ENDPOINT_XFER_ISOC);
2260 
2261 		if (ok)
2262 			ok = (usb_pipein(urb->pipe) && musb->hb_iso_rx)
2263 				|| (usb_pipeout(urb->pipe) && musb->hb_iso_tx);
2264 		if (!ok) {
2265 			ret = -EMSGSIZE;
2266 			goto done;
2267 		}
2268 		qh->maxpacket &= 0x7ff;
2269 	}
2270 
2271 	qh->epnum = usb_endpoint_num(epd);
2272 
2273 	/* NOTE: urb->dev->devnum is wrong during SET_ADDRESS */
2274 	qh->addr_reg = (u8) usb_pipedevice(urb->pipe);
2275 
2276 	/* precompute rxtype/txtype/type0 register */
2277 	type_reg = (qh->type << 4) | qh->epnum;
2278 	switch (urb->dev->speed) {
2279 	case USB_SPEED_LOW:
2280 		type_reg |= 0xc0;
2281 		break;
2282 	case USB_SPEED_FULL:
2283 		type_reg |= 0x80;
2284 		break;
2285 	default:
2286 		type_reg |= 0x40;
2287 	}
2288 	qh->type_reg = type_reg;
2289 
2290 	/* Precompute RXINTERVAL/TXINTERVAL register */
2291 	switch (qh->type) {
2292 	case USB_ENDPOINT_XFER_INT:
2293 		/*
2294 		 * Full/low speeds use the  linear encoding,
2295 		 * high speed uses the logarithmic encoding.
2296 		 */
2297 		if (urb->dev->speed <= USB_SPEED_FULL) {
2298 			interval = max_t(u8, epd->bInterval, 1);
2299 			break;
2300 		}
2301 		/* FALLTHROUGH */
2302 	case USB_ENDPOINT_XFER_ISOC:
2303 		/* ISO always uses logarithmic encoding */
2304 		interval = min_t(u8, epd->bInterval, 16);
2305 		break;
2306 	default:
2307 		/* REVISIT we actually want to use NAK limits, hinting to the
2308 		 * transfer scheduling logic to try some other qh, e.g. try
2309 		 * for 2 msec first:
2310 		 *
2311 		 * interval = (USB_SPEED_HIGH == urb->dev->speed) ? 16 : 2;
2312 		 *
2313 		 * The downside of disabling this is that transfer scheduling
2314 		 * gets VERY unfair for nonperiodic transfers; a misbehaving
2315 		 * peripheral could make that hurt.  That's perfectly normal
2316 		 * for reads from network or serial adapters ... so we have
2317 		 * partial NAKlimit support for bulk RX.
2318 		 *
2319 		 * The upside of disabling it is simpler transfer scheduling.
2320 		 */
2321 		interval = 0;
2322 	}
2323 	qh->intv_reg = interval;
2324 
2325 	/* precompute addressing for external hub/tt ports */
2326 	if (musb->is_multipoint) {
2327 		struct usb_device	*parent = urb->dev->parent;
2328 
2329 		if (parent != hcd->self.root_hub) {
2330 			qh->h_addr_reg = (u8) parent->devnum;
2331 
2332 			/* set up tt info if needed */
2333 			if (urb->dev->tt) {
2334 				qh->h_port_reg = (u8) urb->dev->ttport;
2335 				if (urb->dev->tt->hub)
2336 					qh->h_addr_reg =
2337 						(u8) urb->dev->tt->hub->devnum;
2338 				if (urb->dev->tt->multi)
2339 					qh->h_addr_reg |= 0x80;
2340 			}
2341 		}
2342 	}
2343 
2344 	/* invariant: hep->hcpriv is null OR the qh that's already scheduled.
2345 	 * until we get real dma queues (with an entry for each urb/buffer),
2346 	 * we only have work to do in the former case.
2347 	 */
2348 	spin_lock_irqsave(&musb->lock, flags);
2349 	if (hep->hcpriv || !next_urb(qh)) {
2350 		/* some concurrent activity submitted another urb to hep...
2351 		 * odd, rare, error prone, but legal.
2352 		 */
2353 		kfree(qh);
2354 		qh = NULL;
2355 		ret = 0;
2356 	} else
2357 		ret = musb_schedule(musb, qh,
2358 				epd->bEndpointAddress & USB_ENDPOINT_DIR_MASK);
2359 
2360 	if (ret == 0) {
2361 		urb->hcpriv = qh;
2362 		/* FIXME set urb->start_frame for iso/intr, it's tested in
2363 		 * musb_start_urb(), but otherwise only konicawc cares ...
2364 		 */
2365 	}
2366 	spin_unlock_irqrestore(&musb->lock, flags);
2367 
2368 done:
2369 	if (ret != 0) {
2370 		spin_lock_irqsave(&musb->lock, flags);
2371 		usb_hcd_unlink_urb_from_ep(hcd, urb);
2372 		spin_unlock_irqrestore(&musb->lock, flags);
2373 		kfree(qh);
2374 	}
2375 	return ret;
2376 }
2377 
2378 
2379 /*
2380  * abort a transfer that's at the head of a hardware queue.
2381  * called with controller locked, irqs blocked
2382  * that hardware queue advances to the next transfer, unless prevented
2383  */
2384 static int musb_cleanup_urb(struct urb *urb, struct musb_qh *qh)
2385 {
2386 	struct musb_hw_ep	*ep = qh->hw_ep;
2387 	struct musb		*musb = ep->musb;
2388 	void __iomem		*epio = ep->regs;
2389 	unsigned		hw_end = ep->epnum;
2390 	void __iomem		*regs = ep->musb->mregs;
2391 	int			is_in = usb_pipein(urb->pipe);
2392 	int			status = 0;
2393 	u16			csr;
2394 
2395 	musb_ep_select(regs, hw_end);
2396 
2397 	if (is_dma_capable()) {
2398 		struct dma_channel	*dma;
2399 
2400 		dma = is_in ? ep->rx_channel : ep->tx_channel;
2401 		if (dma) {
2402 			status = ep->musb->dma_controller->channel_abort(dma);
2403 			dev_dbg(musb->controller,
2404 				"abort %cX%d DMA for urb %p --> %d\n",
2405 				is_in ? 'R' : 'T', ep->epnum,
2406 				urb, status);
2407 			urb->actual_length += dma->actual_len;
2408 		}
2409 	}
2410 
2411 	/* turn off DMA requests, discard state, stop polling ... */
2412 	if (ep->epnum && is_in) {
2413 		/* giveback saves bulk toggle */
2414 		csr = musb_h_flush_rxfifo(ep, 0);
2415 
2416 		/* REVISIT we still get an irq; should likely clear the
2417 		 * endpoint's irq status here to avoid bogus irqs.
2418 		 * clearing that status is platform-specific...
2419 		 */
2420 	} else if (ep->epnum) {
2421 		musb_h_tx_flush_fifo(ep);
2422 		csr = musb_readw(epio, MUSB_TXCSR);
2423 		csr &= ~(MUSB_TXCSR_AUTOSET
2424 			| MUSB_TXCSR_DMAENAB
2425 			| MUSB_TXCSR_H_RXSTALL
2426 			| MUSB_TXCSR_H_NAKTIMEOUT
2427 			| MUSB_TXCSR_H_ERROR
2428 			| MUSB_TXCSR_TXPKTRDY);
2429 		musb_writew(epio, MUSB_TXCSR, csr);
2430 		/* REVISIT may need to clear FLUSHFIFO ... */
2431 		musb_writew(epio, MUSB_TXCSR, csr);
2432 		/* flush cpu writebuffer */
2433 		csr = musb_readw(epio, MUSB_TXCSR);
2434 	} else  {
2435 		musb_h_ep0_flush_fifo(ep);
2436 	}
2437 	if (status == 0)
2438 		musb_advance_schedule(ep->musb, urb, ep, is_in);
2439 	return status;
2440 }
2441 
2442 static int musb_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
2443 {
2444 	struct musb		*musb = hcd_to_musb(hcd);
2445 	struct musb_qh		*qh;
2446 	unsigned long		flags;
2447 	int			is_in  = usb_pipein(urb->pipe);
2448 	int			ret;
2449 
2450 	dev_dbg(musb->controller, "urb=%p, dev%d ep%d%s\n", urb,
2451 			usb_pipedevice(urb->pipe),
2452 			usb_pipeendpoint(urb->pipe),
2453 			is_in ? "in" : "out");
2454 
2455 	spin_lock_irqsave(&musb->lock, flags);
2456 	ret = usb_hcd_check_unlink_urb(hcd, urb, status);
2457 	if (ret)
2458 		goto done;
2459 
2460 	qh = urb->hcpriv;
2461 	if (!qh)
2462 		goto done;
2463 
2464 	/*
2465 	 * Any URB not actively programmed into endpoint hardware can be
2466 	 * immediately given back; that's any URB not at the head of an
2467 	 * endpoint queue, unless someday we get real DMA queues.  And even
2468 	 * if it's at the head, it might not be known to the hardware...
2469 	 *
2470 	 * Otherwise abort current transfer, pending DMA, etc.; urb->status
2471 	 * has already been updated.  This is a synchronous abort; it'd be
2472 	 * OK to hold off until after some IRQ, though.
2473 	 *
2474 	 * NOTE: qh is invalid unless !list_empty(&hep->urb_list)
2475 	 */
2476 	if (!qh->is_ready
2477 			|| urb->urb_list.prev != &qh->hep->urb_list
2478 			|| musb_ep_get_qh(qh->hw_ep, is_in) != qh) {
2479 		int	ready = qh->is_ready;
2480 
2481 		qh->is_ready = 0;
2482 		musb_giveback(musb, urb, 0);
2483 		qh->is_ready = ready;
2484 
2485 		/* If nothing else (usually musb_giveback) is using it
2486 		 * and its URB list has emptied, recycle this qh.
2487 		 */
2488 		if (ready && list_empty(&qh->hep->urb_list)) {
2489 			qh->hep->hcpriv = NULL;
2490 			list_del(&qh->ring);
2491 			kfree(qh);
2492 		}
2493 	} else
2494 		ret = musb_cleanup_urb(urb, qh);
2495 done:
2496 	spin_unlock_irqrestore(&musb->lock, flags);
2497 	return ret;
2498 }
2499 
2500 /* disable an endpoint */
2501 static void
2502 musb_h_disable(struct usb_hcd *hcd, struct usb_host_endpoint *hep)
2503 {
2504 	u8			is_in = hep->desc.bEndpointAddress & USB_DIR_IN;
2505 	unsigned long		flags;
2506 	struct musb		*musb = hcd_to_musb(hcd);
2507 	struct musb_qh		*qh;
2508 	struct urb		*urb;
2509 
2510 	spin_lock_irqsave(&musb->lock, flags);
2511 
2512 	qh = hep->hcpriv;
2513 	if (qh == NULL)
2514 		goto exit;
2515 
2516 	/* NOTE: qh is invalid unless !list_empty(&hep->urb_list) */
2517 
2518 	/* Kick the first URB off the hardware, if needed */
2519 	qh->is_ready = 0;
2520 	if (musb_ep_get_qh(qh->hw_ep, is_in) == qh) {
2521 		urb = next_urb(qh);
2522 
2523 		/* make software (then hardware) stop ASAP */
2524 		if (!urb->unlinked)
2525 			urb->status = -ESHUTDOWN;
2526 
2527 		/* cleanup */
2528 		musb_cleanup_urb(urb, qh);
2529 
2530 		/* Then nuke all the others ... and advance the
2531 		 * queue on hw_ep (e.g. bulk ring) when we're done.
2532 		 */
2533 		while (!list_empty(&hep->urb_list)) {
2534 			urb = next_urb(qh);
2535 			urb->status = -ESHUTDOWN;
2536 			musb_advance_schedule(musb, urb, qh->hw_ep, is_in);
2537 		}
2538 	} else {
2539 		/* Just empty the queue; the hardware is busy with
2540 		 * other transfers, and since !qh->is_ready nothing
2541 		 * will activate any of these as it advances.
2542 		 */
2543 		while (!list_empty(&hep->urb_list))
2544 			musb_giveback(musb, next_urb(qh), -ESHUTDOWN);
2545 
2546 		hep->hcpriv = NULL;
2547 		list_del(&qh->ring);
2548 		kfree(qh);
2549 	}
2550 exit:
2551 	spin_unlock_irqrestore(&musb->lock, flags);
2552 }
2553 
2554 static int musb_h_get_frame_number(struct usb_hcd *hcd)
2555 {
2556 	struct musb	*musb = hcd_to_musb(hcd);
2557 
2558 	return musb_readw(musb->mregs, MUSB_FRAME);
2559 }
2560 
2561 static int musb_h_start(struct usb_hcd *hcd)
2562 {
2563 	struct musb	*musb = hcd_to_musb(hcd);
2564 
2565 	/* NOTE: musb_start() is called when the hub driver turns
2566 	 * on port power, or when (OTG) peripheral starts.
2567 	 */
2568 	hcd->state = HC_STATE_RUNNING;
2569 	musb->port1_status = 0;
2570 	return 0;
2571 }
2572 
2573 static void musb_h_stop(struct usb_hcd *hcd)
2574 {
2575 	musb_stop(hcd_to_musb(hcd));
2576 	hcd->state = HC_STATE_HALT;
2577 }
2578 
2579 static int musb_bus_suspend(struct usb_hcd *hcd)
2580 {
2581 	struct musb	*musb = hcd_to_musb(hcd);
2582 	u8		devctl;
2583 
2584 	musb_port_suspend(musb, true);
2585 
2586 	if (!is_host_active(musb))
2587 		return 0;
2588 
2589 	switch (musb->xceiv->otg->state) {
2590 	case OTG_STATE_A_SUSPEND:
2591 		return 0;
2592 	case OTG_STATE_A_WAIT_VRISE:
2593 		/* ID could be grounded even if there's no device
2594 		 * on the other end of the cable.  NOTE that the
2595 		 * A_WAIT_VRISE timers are messy with MUSB...
2596 		 */
2597 		devctl = musb_readb(musb->mregs, MUSB_DEVCTL);
2598 		if ((devctl & MUSB_DEVCTL_VBUS) == MUSB_DEVCTL_VBUS)
2599 			musb->xceiv->otg->state = OTG_STATE_A_WAIT_BCON;
2600 		break;
2601 	default:
2602 		break;
2603 	}
2604 
2605 	if (musb->is_active) {
2606 		WARNING("trying to suspend as %s while active\n",
2607 				usb_otg_state_string(musb->xceiv->otg->state));
2608 		return -EBUSY;
2609 	} else
2610 		return 0;
2611 }
2612 
2613 static int musb_bus_resume(struct usb_hcd *hcd)
2614 {
2615 	struct musb *musb = hcd_to_musb(hcd);
2616 
2617 	if (musb->config &&
2618 	    musb->config->host_port_deassert_reset_at_resume)
2619 		musb_port_reset(musb, false);
2620 
2621 	return 0;
2622 }
2623 
2624 #ifndef CONFIG_MUSB_PIO_ONLY
2625 
2626 #define MUSB_USB_DMA_ALIGN 4
2627 
2628 struct musb_temp_buffer {
2629 	void *kmalloc_ptr;
2630 	void *old_xfer_buffer;
2631 	u8 data[0];
2632 };
2633 
2634 static void musb_free_temp_buffer(struct urb *urb)
2635 {
2636 	enum dma_data_direction dir;
2637 	struct musb_temp_buffer *temp;
2638 	size_t length;
2639 
2640 	if (!(urb->transfer_flags & URB_ALIGNED_TEMP_BUFFER))
2641 		return;
2642 
2643 	dir = usb_urb_dir_in(urb) ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
2644 
2645 	temp = container_of(urb->transfer_buffer, struct musb_temp_buffer,
2646 			    data);
2647 
2648 	if (dir == DMA_FROM_DEVICE) {
2649 		if (usb_pipeisoc(urb->pipe))
2650 			length = urb->transfer_buffer_length;
2651 		else
2652 			length = urb->actual_length;
2653 
2654 		memcpy(temp->old_xfer_buffer, temp->data, length);
2655 	}
2656 	urb->transfer_buffer = temp->old_xfer_buffer;
2657 	kfree(temp->kmalloc_ptr);
2658 
2659 	urb->transfer_flags &= ~URB_ALIGNED_TEMP_BUFFER;
2660 }
2661 
2662 static int musb_alloc_temp_buffer(struct urb *urb, gfp_t mem_flags)
2663 {
2664 	enum dma_data_direction dir;
2665 	struct musb_temp_buffer *temp;
2666 	void *kmalloc_ptr;
2667 	size_t kmalloc_size;
2668 
2669 	if (urb->num_sgs || urb->sg ||
2670 	    urb->transfer_buffer_length == 0 ||
2671 	    !((uintptr_t)urb->transfer_buffer & (MUSB_USB_DMA_ALIGN - 1)))
2672 		return 0;
2673 
2674 	dir = usb_urb_dir_in(urb) ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
2675 
2676 	/* Allocate a buffer with enough padding for alignment */
2677 	kmalloc_size = urb->transfer_buffer_length +
2678 		sizeof(struct musb_temp_buffer) + MUSB_USB_DMA_ALIGN - 1;
2679 
2680 	kmalloc_ptr = kmalloc(kmalloc_size, mem_flags);
2681 	if (!kmalloc_ptr)
2682 		return -ENOMEM;
2683 
2684 	/* Position our struct temp_buffer such that data is aligned */
2685 	temp = PTR_ALIGN(kmalloc_ptr, MUSB_USB_DMA_ALIGN);
2686 
2687 
2688 	temp->kmalloc_ptr = kmalloc_ptr;
2689 	temp->old_xfer_buffer = urb->transfer_buffer;
2690 	if (dir == DMA_TO_DEVICE)
2691 		memcpy(temp->data, urb->transfer_buffer,
2692 		       urb->transfer_buffer_length);
2693 	urb->transfer_buffer = temp->data;
2694 
2695 	urb->transfer_flags |= URB_ALIGNED_TEMP_BUFFER;
2696 
2697 	return 0;
2698 }
2699 
2700 static int musb_map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb,
2701 				      gfp_t mem_flags)
2702 {
2703 	struct musb	*musb = hcd_to_musb(hcd);
2704 	int ret;
2705 
2706 	/*
2707 	 * The DMA engine in RTL1.8 and above cannot handle
2708 	 * DMA addresses that are not aligned to a 4 byte boundary.
2709 	 * For such engine implemented (un)map_urb_for_dma hooks.
2710 	 * Do not use these hooks for RTL<1.8
2711 	 */
2712 	if (musb->hwvers < MUSB_HWVERS_1800)
2713 		return usb_hcd_map_urb_for_dma(hcd, urb, mem_flags);
2714 
2715 	ret = musb_alloc_temp_buffer(urb, mem_flags);
2716 	if (ret)
2717 		return ret;
2718 
2719 	ret = usb_hcd_map_urb_for_dma(hcd, urb, mem_flags);
2720 	if (ret)
2721 		musb_free_temp_buffer(urb);
2722 
2723 	return ret;
2724 }
2725 
2726 static void musb_unmap_urb_for_dma(struct usb_hcd *hcd, struct urb *urb)
2727 {
2728 	struct musb	*musb = hcd_to_musb(hcd);
2729 
2730 	usb_hcd_unmap_urb_for_dma(hcd, urb);
2731 
2732 	/* Do not use this hook for RTL<1.8 (see description above) */
2733 	if (musb->hwvers < MUSB_HWVERS_1800)
2734 		return;
2735 
2736 	musb_free_temp_buffer(urb);
2737 }
2738 #endif /* !CONFIG_MUSB_PIO_ONLY */
2739 
2740 static const struct hc_driver musb_hc_driver = {
2741 	.description		= "musb-hcd",
2742 	.product_desc		= "MUSB HDRC host driver",
2743 	.hcd_priv_size		= sizeof(struct musb *),
2744 	.flags			= HCD_USB2 | HCD_MEMORY,
2745 
2746 	/* not using irq handler or reset hooks from usbcore, since
2747 	 * those must be shared with peripheral code for OTG configs
2748 	 */
2749 
2750 	.start			= musb_h_start,
2751 	.stop			= musb_h_stop,
2752 
2753 	.get_frame_number	= musb_h_get_frame_number,
2754 
2755 	.urb_enqueue		= musb_urb_enqueue,
2756 	.urb_dequeue		= musb_urb_dequeue,
2757 	.endpoint_disable	= musb_h_disable,
2758 
2759 #ifndef CONFIG_MUSB_PIO_ONLY
2760 	.map_urb_for_dma	= musb_map_urb_for_dma,
2761 	.unmap_urb_for_dma	= musb_unmap_urb_for_dma,
2762 #endif
2763 
2764 	.hub_status_data	= musb_hub_status_data,
2765 	.hub_control		= musb_hub_control,
2766 	.bus_suspend		= musb_bus_suspend,
2767 	.bus_resume		= musb_bus_resume,
2768 	/* .start_port_reset	= NULL, */
2769 	/* .hub_irq_enable	= NULL, */
2770 };
2771 
2772 int musb_host_alloc(struct musb *musb)
2773 {
2774 	struct device	*dev = musb->controller;
2775 
2776 	/* usbcore sets dev->driver_data to hcd, and sometimes uses that... */
2777 	musb->hcd = usb_create_hcd(&musb_hc_driver, dev, dev_name(dev));
2778 	if (!musb->hcd)
2779 		return -EINVAL;
2780 
2781 	*musb->hcd->hcd_priv = (unsigned long) musb;
2782 	musb->hcd->self.uses_pio_for_control = 1;
2783 	musb->hcd->uses_new_polling = 1;
2784 	musb->hcd->has_tt = 1;
2785 
2786 	return 0;
2787 }
2788 
2789 void musb_host_cleanup(struct musb *musb)
2790 {
2791 	if (musb->port_mode == MUSB_PORT_MODE_GADGET)
2792 		return;
2793 	usb_remove_hcd(musb->hcd);
2794 }
2795 
2796 void musb_host_free(struct musb *musb)
2797 {
2798 	usb_put_hcd(musb->hcd);
2799 }
2800 
2801 int musb_host_setup(struct musb *musb, int power_budget)
2802 {
2803 	int ret;
2804 	struct usb_hcd *hcd = musb->hcd;
2805 
2806 	MUSB_HST_MODE(musb);
2807 	musb->xceiv->otg->default_a = 1;
2808 	musb->xceiv->otg->state = OTG_STATE_A_IDLE;
2809 
2810 	otg_set_host(musb->xceiv->otg, &hcd->self);
2811 	hcd->self.otg_port = 1;
2812 	musb->xceiv->otg->host = &hcd->self;
2813 	hcd->power_budget = 2 * (power_budget ? : 250);
2814 
2815 	ret = usb_add_hcd(hcd, 0, 0);
2816 	if (ret < 0)
2817 		return ret;
2818 
2819 	device_wakeup_enable(hcd->self.controller);
2820 	return 0;
2821 }
2822 
2823 void musb_host_resume_root_hub(struct musb *musb)
2824 {
2825 	usb_hcd_resume_root_hub(musb->hcd);
2826 }
2827 
2828 void musb_host_poke_root_hub(struct musb *musb)
2829 {
2830 	MUSB_HST_MODE(musb);
2831 	if (musb->hcd->status_urb)
2832 		usb_hcd_poll_rh_status(musb->hcd);
2833 	else
2834 		usb_hcd_resume_root_hub(musb->hcd);
2835 }
2836