xref: /linux/drivers/usb/musb/musb_gadget.c (revision bcefe12eff5dca6fdfa94ed85e5bee66380d5cd9)
1 /*
2  * MUSB OTG driver peripheral support
3  *
4  * Copyright 2005 Mentor Graphics Corporation
5  * Copyright (C) 2005-2006 by Texas Instruments
6  * Copyright (C) 2006-2007 Nokia Corporation
7  *
8  * This program is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU General Public License
10  * version 2 as published by the Free Software Foundation.
11  *
12  * This program is distributed in the hope that it will be useful, but
13  * WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15  * General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with this program; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
20  * 02110-1301 USA
21  *
22  * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
23  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
24  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
25  * NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
27  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
28  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
29  * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
31  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32  *
33  */
34 
35 #include <linux/kernel.h>
36 #include <linux/list.h>
37 #include <linux/timer.h>
38 #include <linux/module.h>
39 #include <linux/smp.h>
40 #include <linux/spinlock.h>
41 #include <linux/delay.h>
42 #include <linux/moduleparam.h>
43 #include <linux/stat.h>
44 #include <linux/dma-mapping.h>
45 
46 #include "musb_core.h"
47 
48 
49 /* MUSB PERIPHERAL status 3-mar-2006:
50  *
51  * - EP0 seems solid.  It passes both USBCV and usbtest control cases.
52  *   Minor glitches:
53  *
54  *     + remote wakeup to Linux hosts work, but saw USBCV failures;
55  *       in one test run (operator error?)
56  *     + endpoint halt tests -- in both usbtest and usbcv -- seem
57  *       to break when dma is enabled ... is something wrongly
58  *       clearing SENDSTALL?
59  *
60  * - Mass storage behaved ok when last tested.  Network traffic patterns
61  *   (with lots of short transfers etc) need retesting; they turn up the
62  *   worst cases of the DMA, since short packets are typical but are not
63  *   required.
64  *
65  * - TX/IN
66  *     + both pio and dma behave in with network and g_zero tests
67  *     + no cppi throughput issues other than no-hw-queueing
68  *     + failed with FLAT_REG (DaVinci)
69  *     + seems to behave with double buffering, PIO -and- CPPI
70  *     + with gadgetfs + AIO, requests got lost?
71  *
72  * - RX/OUT
73  *     + both pio and dma behave in with network and g_zero tests
74  *     + dma is slow in typical case (short_not_ok is clear)
75  *     + double buffering ok with PIO
76  *     + double buffering *FAILS* with CPPI, wrong data bytes sometimes
77  *     + request lossage observed with gadgetfs
78  *
79  * - ISO not tested ... might work, but only weakly isochronous
80  *
81  * - Gadget driver disabling of softconnect during bind() is ignored; so
82  *   drivers can't hold off host requests until userspace is ready.
83  *   (Workaround:  they can turn it off later.)
84  *
85  * - PORTABILITY (assumes PIO works):
86  *     + DaVinci, basically works with cppi dma
87  *     + OMAP 2430, ditto with mentor dma
88  *     + TUSB 6010, platform-specific dma in the works
89  */
90 
91 /* ----------------------------------------------------------------------- */
92 
93 /*
94  * Immediately complete a request.
95  *
96  * @param request the request to complete
97  * @param status the status to complete the request with
98  * Context: controller locked, IRQs blocked.
99  */
100 void musb_g_giveback(
101 	struct musb_ep		*ep,
102 	struct usb_request	*request,
103 	int			status)
104 __releases(ep->musb->lock)
105 __acquires(ep->musb->lock)
106 {
107 	struct musb_request	*req;
108 	struct musb		*musb;
109 	int			busy = ep->busy;
110 
111 	req = to_musb_request(request);
112 
113 	list_del(&request->list);
114 	if (req->request.status == -EINPROGRESS)
115 		req->request.status = status;
116 	musb = req->musb;
117 
118 	ep->busy = 1;
119 	spin_unlock(&musb->lock);
120 	if (is_dma_capable()) {
121 		if (req->mapped) {
122 			dma_unmap_single(musb->controller,
123 					req->request.dma,
124 					req->request.length,
125 					req->tx
126 						? DMA_TO_DEVICE
127 						: DMA_FROM_DEVICE);
128 			req->request.dma = DMA_ADDR_INVALID;
129 			req->mapped = 0;
130 		} else if (req->request.dma != DMA_ADDR_INVALID)
131 			dma_sync_single_for_cpu(musb->controller,
132 					req->request.dma,
133 					req->request.length,
134 					req->tx
135 						? DMA_TO_DEVICE
136 						: DMA_FROM_DEVICE);
137 	}
138 	if (request->status == 0)
139 		DBG(5, "%s done request %p,  %d/%d\n",
140 				ep->end_point.name, request,
141 				req->request.actual, req->request.length);
142 	else
143 		DBG(2, "%s request %p, %d/%d fault %d\n",
144 				ep->end_point.name, request,
145 				req->request.actual, req->request.length,
146 				request->status);
147 	req->request.complete(&req->ep->end_point, &req->request);
148 	spin_lock(&musb->lock);
149 	ep->busy = busy;
150 }
151 
152 /* ----------------------------------------------------------------------- */
153 
154 /*
155  * Abort requests queued to an endpoint using the status. Synchronous.
156  * caller locked controller and blocked irqs, and selected this ep.
157  */
158 static void nuke(struct musb_ep *ep, const int status)
159 {
160 	struct musb_request	*req = NULL;
161 	void __iomem *epio = ep->musb->endpoints[ep->current_epnum].regs;
162 
163 	ep->busy = 1;
164 
165 	if (is_dma_capable() && ep->dma) {
166 		struct dma_controller	*c = ep->musb->dma_controller;
167 		int value;
168 
169 		if (ep->is_in) {
170 			/*
171 			 * The programming guide says that we must not clear
172 			 * the DMAMODE bit before DMAENAB, so we only
173 			 * clear it in the second write...
174 			 */
175 			musb_writew(epio, MUSB_TXCSR,
176 				    MUSB_TXCSR_DMAMODE | MUSB_TXCSR_FLUSHFIFO);
177 			musb_writew(epio, MUSB_TXCSR,
178 					0 | MUSB_TXCSR_FLUSHFIFO);
179 		} else {
180 			musb_writew(epio, MUSB_RXCSR,
181 					0 | MUSB_RXCSR_FLUSHFIFO);
182 			musb_writew(epio, MUSB_RXCSR,
183 					0 | MUSB_RXCSR_FLUSHFIFO);
184 		}
185 
186 		value = c->channel_abort(ep->dma);
187 		DBG(value ? 1 : 6, "%s: abort DMA --> %d\n", ep->name, value);
188 		c->channel_release(ep->dma);
189 		ep->dma = NULL;
190 	}
191 
192 	while (!list_empty(&(ep->req_list))) {
193 		req = container_of(ep->req_list.next, struct musb_request,
194 				request.list);
195 		musb_g_giveback(ep, &req->request, status);
196 	}
197 }
198 
199 /* ----------------------------------------------------------------------- */
200 
201 /* Data transfers - pure PIO, pure DMA, or mixed mode */
202 
203 /*
204  * This assumes the separate CPPI engine is responding to DMA requests
205  * from the usb core ... sequenced a bit differently from mentor dma.
206  */
207 
208 static inline int max_ep_writesize(struct musb *musb, struct musb_ep *ep)
209 {
210 	if (can_bulk_split(musb, ep->type))
211 		return ep->hw_ep->max_packet_sz_tx;
212 	else
213 		return ep->packet_sz;
214 }
215 
216 
217 #ifdef CONFIG_USB_INVENTRA_DMA
218 
219 /* Peripheral tx (IN) using Mentor DMA works as follows:
220 	Only mode 0 is used for transfers <= wPktSize,
221 	mode 1 is used for larger transfers,
222 
223 	One of the following happens:
224 	- Host sends IN token which causes an endpoint interrupt
225 		-> TxAvail
226 			-> if DMA is currently busy, exit.
227 			-> if queue is non-empty, txstate().
228 
229 	- Request is queued by the gadget driver.
230 		-> if queue was previously empty, txstate()
231 
232 	txstate()
233 		-> start
234 		  /\	-> setup DMA
235 		  |     (data is transferred to the FIFO, then sent out when
236 		  |	IN token(s) are recd from Host.
237 		  |		-> DMA interrupt on completion
238 		  |		   calls TxAvail.
239 		  |		      -> stop DMA, ~DMAENAB,
240 		  |		      -> set TxPktRdy for last short pkt or zlp
241 		  |		      -> Complete Request
242 		  |		      -> Continue next request (call txstate)
243 		  |___________________________________|
244 
245  * Non-Mentor DMA engines can of course work differently, such as by
246  * upleveling from irq-per-packet to irq-per-buffer.
247  */
248 
249 #endif
250 
251 /*
252  * An endpoint is transmitting data. This can be called either from
253  * the IRQ routine or from ep.queue() to kickstart a request on an
254  * endpoint.
255  *
256  * Context: controller locked, IRQs blocked, endpoint selected
257  */
258 static void txstate(struct musb *musb, struct musb_request *req)
259 {
260 	u8			epnum = req->epnum;
261 	struct musb_ep		*musb_ep;
262 	void __iomem		*epio = musb->endpoints[epnum].regs;
263 	struct usb_request	*request;
264 	u16			fifo_count = 0, csr;
265 	int			use_dma = 0;
266 
267 	musb_ep = req->ep;
268 
269 	/* we shouldn't get here while DMA is active ... but we do ... */
270 	if (dma_channel_status(musb_ep->dma) == MUSB_DMA_STATUS_BUSY) {
271 		DBG(4, "dma pending...\n");
272 		return;
273 	}
274 
275 	/* read TXCSR before */
276 	csr = musb_readw(epio, MUSB_TXCSR);
277 
278 	request = &req->request;
279 	fifo_count = min(max_ep_writesize(musb, musb_ep),
280 			(int)(request->length - request->actual));
281 
282 	if (csr & MUSB_TXCSR_TXPKTRDY) {
283 		DBG(5, "%s old packet still ready , txcsr %03x\n",
284 				musb_ep->end_point.name, csr);
285 		return;
286 	}
287 
288 	if (csr & MUSB_TXCSR_P_SENDSTALL) {
289 		DBG(5, "%s stalling, txcsr %03x\n",
290 				musb_ep->end_point.name, csr);
291 		return;
292 	}
293 
294 	DBG(4, "hw_ep%d, maxpacket %d, fifo count %d, txcsr %03x\n",
295 			epnum, musb_ep->packet_sz, fifo_count,
296 			csr);
297 
298 #ifndef	CONFIG_MUSB_PIO_ONLY
299 	if (is_dma_capable() && musb_ep->dma) {
300 		struct dma_controller	*c = musb->dma_controller;
301 
302 		use_dma = (request->dma != DMA_ADDR_INVALID);
303 
304 		/* MUSB_TXCSR_P_ISO is still set correctly */
305 
306 #ifdef CONFIG_USB_INVENTRA_DMA
307 		{
308 			size_t request_size;
309 
310 			/* setup DMA, then program endpoint CSR */
311 			request_size = min(request->length,
312 						musb_ep->dma->max_len);
313 			if (request_size < musb_ep->packet_sz)
314 				musb_ep->dma->desired_mode = 0;
315 			else
316 				musb_ep->dma->desired_mode = 1;
317 
318 			use_dma = use_dma && c->channel_program(
319 					musb_ep->dma, musb_ep->packet_sz,
320 					musb_ep->dma->desired_mode,
321 					request->dma, request_size);
322 			if (use_dma) {
323 				if (musb_ep->dma->desired_mode == 0) {
324 					/*
325 					 * We must not clear the DMAMODE bit
326 					 * before the DMAENAB bit -- and the
327 					 * latter doesn't always get cleared
328 					 * before we get here...
329 					 */
330 					csr &= ~(MUSB_TXCSR_AUTOSET
331 						| MUSB_TXCSR_DMAENAB);
332 					musb_writew(epio, MUSB_TXCSR, csr
333 						| MUSB_TXCSR_P_WZC_BITS);
334 					csr &= ~MUSB_TXCSR_DMAMODE;
335 					csr |= (MUSB_TXCSR_DMAENAB |
336 							MUSB_TXCSR_MODE);
337 					/* against programming guide */
338 				} else
339 					csr |= (MUSB_TXCSR_AUTOSET
340 							| MUSB_TXCSR_DMAENAB
341 							| MUSB_TXCSR_DMAMODE
342 							| MUSB_TXCSR_MODE);
343 
344 				csr &= ~MUSB_TXCSR_P_UNDERRUN;
345 				musb_writew(epio, MUSB_TXCSR, csr);
346 			}
347 		}
348 
349 #elif defined(CONFIG_USB_TI_CPPI_DMA)
350 		/* program endpoint CSR first, then setup DMA */
351 		csr &= ~(MUSB_TXCSR_P_UNDERRUN | MUSB_TXCSR_TXPKTRDY);
352 		csr |= MUSB_TXCSR_DMAENAB | MUSB_TXCSR_DMAMODE |
353 		       MUSB_TXCSR_MODE;
354 		musb_writew(epio, MUSB_TXCSR,
355 			(MUSB_TXCSR_P_WZC_BITS & ~MUSB_TXCSR_P_UNDERRUN)
356 				| csr);
357 
358 		/* ensure writebuffer is empty */
359 		csr = musb_readw(epio, MUSB_TXCSR);
360 
361 		/* NOTE host side sets DMAENAB later than this; both are
362 		 * OK since the transfer dma glue (between CPPI and Mentor
363 		 * fifos) just tells CPPI it could start.  Data only moves
364 		 * to the USB TX fifo when both fifos are ready.
365 		 */
366 
367 		/* "mode" is irrelevant here; handle terminating ZLPs like
368 		 * PIO does, since the hardware RNDIS mode seems unreliable
369 		 * except for the last-packet-is-already-short case.
370 		 */
371 		use_dma = use_dma && c->channel_program(
372 				musb_ep->dma, musb_ep->packet_sz,
373 				0,
374 				request->dma,
375 				request->length);
376 		if (!use_dma) {
377 			c->channel_release(musb_ep->dma);
378 			musb_ep->dma = NULL;
379 			csr &= ~MUSB_TXCSR_DMAENAB;
380 			musb_writew(epio, MUSB_TXCSR, csr);
381 			/* invariant: prequest->buf is non-null */
382 		}
383 #elif defined(CONFIG_USB_TUSB_OMAP_DMA)
384 		use_dma = use_dma && c->channel_program(
385 				musb_ep->dma, musb_ep->packet_sz,
386 				request->zero,
387 				request->dma,
388 				request->length);
389 #endif
390 	}
391 #endif
392 
393 	if (!use_dma) {
394 		musb_write_fifo(musb_ep->hw_ep, fifo_count,
395 				(u8 *) (request->buf + request->actual));
396 		request->actual += fifo_count;
397 		csr |= MUSB_TXCSR_TXPKTRDY;
398 		csr &= ~MUSB_TXCSR_P_UNDERRUN;
399 		musb_writew(epio, MUSB_TXCSR, csr);
400 	}
401 
402 	/* host may already have the data when this message shows... */
403 	DBG(3, "%s TX/IN %s len %d/%d, txcsr %04x, fifo %d/%d\n",
404 			musb_ep->end_point.name, use_dma ? "dma" : "pio",
405 			request->actual, request->length,
406 			musb_readw(epio, MUSB_TXCSR),
407 			fifo_count,
408 			musb_readw(epio, MUSB_TXMAXP));
409 }
410 
411 /*
412  * FIFO state update (e.g. data ready).
413  * Called from IRQ,  with controller locked.
414  */
415 void musb_g_tx(struct musb *musb, u8 epnum)
416 {
417 	u16			csr;
418 	struct usb_request	*request;
419 	u8 __iomem		*mbase = musb->mregs;
420 	struct musb_ep		*musb_ep = &musb->endpoints[epnum].ep_in;
421 	void __iomem		*epio = musb->endpoints[epnum].regs;
422 	struct dma_channel	*dma;
423 
424 	musb_ep_select(mbase, epnum);
425 	request = next_request(musb_ep);
426 
427 	csr = musb_readw(epio, MUSB_TXCSR);
428 	DBG(4, "<== %s, txcsr %04x\n", musb_ep->end_point.name, csr);
429 
430 	dma = is_dma_capable() ? musb_ep->dma : NULL;
431 	do {
432 		/* REVISIT for high bandwidth, MUSB_TXCSR_P_INCOMPTX
433 		 * probably rates reporting as a host error
434 		 */
435 		if (csr & MUSB_TXCSR_P_SENTSTALL) {
436 			csr |= MUSB_TXCSR_P_WZC_BITS;
437 			csr &= ~MUSB_TXCSR_P_SENTSTALL;
438 			musb_writew(epio, MUSB_TXCSR, csr);
439 			if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
440 				dma->status = MUSB_DMA_STATUS_CORE_ABORT;
441 				musb->dma_controller->channel_abort(dma);
442 			}
443 
444 			if (request)
445 				musb_g_giveback(musb_ep, request, -EPIPE);
446 
447 			break;
448 		}
449 
450 		if (csr & MUSB_TXCSR_P_UNDERRUN) {
451 			/* we NAKed, no big deal ... little reason to care */
452 			csr |= MUSB_TXCSR_P_WZC_BITS;
453 			csr &= ~(MUSB_TXCSR_P_UNDERRUN
454 					| MUSB_TXCSR_TXPKTRDY);
455 			musb_writew(epio, MUSB_TXCSR, csr);
456 			DBG(20, "underrun on ep%d, req %p\n", epnum, request);
457 		}
458 
459 		if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
460 			/* SHOULD NOT HAPPEN ... has with cppi though, after
461 			 * changing SENDSTALL (and other cases); harmless?
462 			 */
463 			DBG(5, "%s dma still busy?\n", musb_ep->end_point.name);
464 			break;
465 		}
466 
467 		if (request) {
468 			u8	is_dma = 0;
469 
470 			if (dma && (csr & MUSB_TXCSR_DMAENAB)) {
471 				is_dma = 1;
472 				csr |= MUSB_TXCSR_P_WZC_BITS;
473 				csr &= ~(MUSB_TXCSR_DMAENAB
474 						| MUSB_TXCSR_P_UNDERRUN
475 						| MUSB_TXCSR_TXPKTRDY);
476 				musb_writew(epio, MUSB_TXCSR, csr);
477 				/* ensure writebuffer is empty */
478 				csr = musb_readw(epio, MUSB_TXCSR);
479 				request->actual += musb_ep->dma->actual_len;
480 				DBG(4, "TXCSR%d %04x, dma off, "
481 						"len %zu, req %p\n",
482 					epnum, csr,
483 					musb_ep->dma->actual_len,
484 					request);
485 			}
486 
487 			if (is_dma || request->actual == request->length) {
488 
489 				/* First, maybe a terminating short packet.
490 				 * Some DMA engines might handle this by
491 				 * themselves.
492 				 */
493 				if ((request->zero
494 						&& request->length
495 						&& (request->length
496 							% musb_ep->packet_sz)
497 							== 0)
498 #ifdef CONFIG_USB_INVENTRA_DMA
499 					|| (is_dma &&
500 						((!dma->desired_mode) ||
501 						    (request->actual &
502 						    (musb_ep->packet_sz - 1))))
503 #endif
504 				) {
505 					/* on dma completion, fifo may not
506 					 * be available yet ...
507 					 */
508 					if (csr & MUSB_TXCSR_TXPKTRDY)
509 						break;
510 
511 					DBG(4, "sending zero pkt\n");
512 					musb_writew(epio, MUSB_TXCSR,
513 							MUSB_TXCSR_MODE
514 							| MUSB_TXCSR_TXPKTRDY);
515 					request->zero = 0;
516 				}
517 
518 				/* ... or if not, then complete it */
519 				musb_g_giveback(musb_ep, request, 0);
520 
521 				/* kickstart next transfer if appropriate;
522 				 * the packet that just completed might not
523 				 * be transmitted for hours or days.
524 				 * REVISIT for double buffering...
525 				 * FIXME revisit for stalls too...
526 				 */
527 				musb_ep_select(mbase, epnum);
528 				csr = musb_readw(epio, MUSB_TXCSR);
529 				if (csr & MUSB_TXCSR_FIFONOTEMPTY)
530 					break;
531 				request = musb_ep->desc
532 						? next_request(musb_ep)
533 						: NULL;
534 				if (!request) {
535 					DBG(4, "%s idle now\n",
536 						musb_ep->end_point.name);
537 					break;
538 				}
539 			}
540 
541 			txstate(musb, to_musb_request(request));
542 		}
543 
544 	} while (0);
545 }
546 
547 /* ------------------------------------------------------------ */
548 
549 #ifdef CONFIG_USB_INVENTRA_DMA
550 
551 /* Peripheral rx (OUT) using Mentor DMA works as follows:
552 	- Only mode 0 is used.
553 
554 	- Request is queued by the gadget class driver.
555 		-> if queue was previously empty, rxstate()
556 
557 	- Host sends OUT token which causes an endpoint interrupt
558 	  /\      -> RxReady
559 	  |	      -> if request queued, call rxstate
560 	  |		/\	-> setup DMA
561 	  |		|	     -> DMA interrupt on completion
562 	  |		|		-> RxReady
563 	  |		|		      -> stop DMA
564 	  |		|		      -> ack the read
565 	  |		|		      -> if data recd = max expected
566 	  |		|				by the request, or host
567 	  |		|				sent a short packet,
568 	  |		|				complete the request,
569 	  |		|				and start the next one.
570 	  |		|_____________________________________|
571 	  |					 else just wait for the host
572 	  |					    to send the next OUT token.
573 	  |__________________________________________________|
574 
575  * Non-Mentor DMA engines can of course work differently.
576  */
577 
578 #endif
579 
580 /*
581  * Context: controller locked, IRQs blocked, endpoint selected
582  */
583 static void rxstate(struct musb *musb, struct musb_request *req)
584 {
585 	u16			csr = 0;
586 	const u8		epnum = req->epnum;
587 	struct usb_request	*request = &req->request;
588 	struct musb_ep		*musb_ep = &musb->endpoints[epnum].ep_out;
589 	void __iomem		*epio = musb->endpoints[epnum].regs;
590 	unsigned		fifo_count = 0;
591 	u16			len = musb_ep->packet_sz;
592 
593 	csr = musb_readw(epio, MUSB_RXCSR);
594 
595 	if (is_cppi_enabled() && musb_ep->dma) {
596 		struct dma_controller	*c = musb->dma_controller;
597 		struct dma_channel	*channel = musb_ep->dma;
598 
599 		/* NOTE:  CPPI won't actually stop advancing the DMA
600 		 * queue after short packet transfers, so this is almost
601 		 * always going to run as IRQ-per-packet DMA so that
602 		 * faults will be handled correctly.
603 		 */
604 		if (c->channel_program(channel,
605 				musb_ep->packet_sz,
606 				!request->short_not_ok,
607 				request->dma + request->actual,
608 				request->length - request->actual)) {
609 
610 			/* make sure that if an rxpkt arrived after the irq,
611 			 * the cppi engine will be ready to take it as soon
612 			 * as DMA is enabled
613 			 */
614 			csr &= ~(MUSB_RXCSR_AUTOCLEAR
615 					| MUSB_RXCSR_DMAMODE);
616 			csr |= MUSB_RXCSR_DMAENAB | MUSB_RXCSR_P_WZC_BITS;
617 			musb_writew(epio, MUSB_RXCSR, csr);
618 			return;
619 		}
620 	}
621 
622 	if (csr & MUSB_RXCSR_RXPKTRDY) {
623 		len = musb_readw(epio, MUSB_RXCOUNT);
624 		if (request->actual < request->length) {
625 #ifdef CONFIG_USB_INVENTRA_DMA
626 			if (is_dma_capable() && musb_ep->dma) {
627 				struct dma_controller	*c;
628 				struct dma_channel	*channel;
629 				int			use_dma = 0;
630 
631 				c = musb->dma_controller;
632 				channel = musb_ep->dma;
633 
634 	/* We use DMA Req mode 0 in rx_csr, and DMA controller operates in
635 	 * mode 0 only. So we do not get endpoint interrupts due to DMA
636 	 * completion. We only get interrupts from DMA controller.
637 	 *
638 	 * We could operate in DMA mode 1 if we knew the size of the tranfer
639 	 * in advance. For mass storage class, request->length = what the host
640 	 * sends, so that'd work.  But for pretty much everything else,
641 	 * request->length is routinely more than what the host sends. For
642 	 * most these gadgets, end of is signified either by a short packet,
643 	 * or filling the last byte of the buffer.  (Sending extra data in
644 	 * that last pckate should trigger an overflow fault.)  But in mode 1,
645 	 * we don't get DMA completion interrrupt for short packets.
646 	 *
647 	 * Theoretically, we could enable DMAReq irq (MUSB_RXCSR_DMAMODE = 1),
648 	 * to get endpoint interrupt on every DMA req, but that didn't seem
649 	 * to work reliably.
650 	 *
651 	 * REVISIT an updated g_file_storage can set req->short_not_ok, which
652 	 * then becomes usable as a runtime "use mode 1" hint...
653 	 */
654 
655 				csr |= MUSB_RXCSR_DMAENAB;
656 #ifdef USE_MODE1
657 				csr |= MUSB_RXCSR_AUTOCLEAR;
658 				/* csr |= MUSB_RXCSR_DMAMODE; */
659 
660 				/* this special sequence (enabling and then
661 				 * disabling MUSB_RXCSR_DMAMODE) is required
662 				 * to get DMAReq to activate
663 				 */
664 				musb_writew(epio, MUSB_RXCSR,
665 					csr | MUSB_RXCSR_DMAMODE);
666 #endif
667 				musb_writew(epio, MUSB_RXCSR, csr);
668 
669 				if (request->actual < request->length) {
670 					int transfer_size = 0;
671 #ifdef USE_MODE1
672 					transfer_size = min(request->length,
673 							channel->max_len);
674 #else
675 					transfer_size = len;
676 #endif
677 					if (transfer_size <= musb_ep->packet_sz)
678 						musb_ep->dma->desired_mode = 0;
679 					else
680 						musb_ep->dma->desired_mode = 1;
681 
682 					use_dma = c->channel_program(
683 							channel,
684 							musb_ep->packet_sz,
685 							channel->desired_mode,
686 							request->dma
687 							+ request->actual,
688 							transfer_size);
689 				}
690 
691 				if (use_dma)
692 					return;
693 			}
694 #endif	/* Mentor's DMA */
695 
696 			fifo_count = request->length - request->actual;
697 			DBG(3, "%s OUT/RX pio fifo %d/%d, maxpacket %d\n",
698 					musb_ep->end_point.name,
699 					len, fifo_count,
700 					musb_ep->packet_sz);
701 
702 			fifo_count = min_t(unsigned, len, fifo_count);
703 
704 #ifdef	CONFIG_USB_TUSB_OMAP_DMA
705 			if (tusb_dma_omap() && musb_ep->dma) {
706 				struct dma_controller *c = musb->dma_controller;
707 				struct dma_channel *channel = musb_ep->dma;
708 				u32 dma_addr = request->dma + request->actual;
709 				int ret;
710 
711 				ret = c->channel_program(channel,
712 						musb_ep->packet_sz,
713 						channel->desired_mode,
714 						dma_addr,
715 						fifo_count);
716 				if (ret)
717 					return;
718 			}
719 #endif
720 
721 			musb_read_fifo(musb_ep->hw_ep, fifo_count, (u8 *)
722 					(request->buf + request->actual));
723 			request->actual += fifo_count;
724 
725 			/* REVISIT if we left anything in the fifo, flush
726 			 * it and report -EOVERFLOW
727 			 */
728 
729 			/* ack the read! */
730 			csr |= MUSB_RXCSR_P_WZC_BITS;
731 			csr &= ~MUSB_RXCSR_RXPKTRDY;
732 			musb_writew(epio, MUSB_RXCSR, csr);
733 		}
734 	}
735 
736 	/* reach the end or short packet detected */
737 	if (request->actual == request->length || len < musb_ep->packet_sz)
738 		musb_g_giveback(musb_ep, request, 0);
739 }
740 
741 /*
742  * Data ready for a request; called from IRQ
743  */
744 void musb_g_rx(struct musb *musb, u8 epnum)
745 {
746 	u16			csr;
747 	struct usb_request	*request;
748 	void __iomem		*mbase = musb->mregs;
749 	struct musb_ep		*musb_ep = &musb->endpoints[epnum].ep_out;
750 	void __iomem		*epio = musb->endpoints[epnum].regs;
751 	struct dma_channel	*dma;
752 
753 	musb_ep_select(mbase, epnum);
754 
755 	request = next_request(musb_ep);
756 
757 	csr = musb_readw(epio, MUSB_RXCSR);
758 	dma = is_dma_capable() ? musb_ep->dma : NULL;
759 
760 	DBG(4, "<== %s, rxcsr %04x%s %p\n", musb_ep->end_point.name,
761 			csr, dma ? " (dma)" : "", request);
762 
763 	if (csr & MUSB_RXCSR_P_SENTSTALL) {
764 		if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
765 			dma->status = MUSB_DMA_STATUS_CORE_ABORT;
766 			(void) musb->dma_controller->channel_abort(dma);
767 			request->actual += musb_ep->dma->actual_len;
768 		}
769 
770 		csr |= MUSB_RXCSR_P_WZC_BITS;
771 		csr &= ~MUSB_RXCSR_P_SENTSTALL;
772 		musb_writew(epio, MUSB_RXCSR, csr);
773 
774 		if (request)
775 			musb_g_giveback(musb_ep, request, -EPIPE);
776 		goto done;
777 	}
778 
779 	if (csr & MUSB_RXCSR_P_OVERRUN) {
780 		/* csr |= MUSB_RXCSR_P_WZC_BITS; */
781 		csr &= ~MUSB_RXCSR_P_OVERRUN;
782 		musb_writew(epio, MUSB_RXCSR, csr);
783 
784 		DBG(3, "%s iso overrun on %p\n", musb_ep->name, request);
785 		if (request && request->status == -EINPROGRESS)
786 			request->status = -EOVERFLOW;
787 	}
788 	if (csr & MUSB_RXCSR_INCOMPRX) {
789 		/* REVISIT not necessarily an error */
790 		DBG(4, "%s, incomprx\n", musb_ep->end_point.name);
791 	}
792 
793 	if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
794 		/* "should not happen"; likely RXPKTRDY pending for DMA */
795 		DBG((csr & MUSB_RXCSR_DMAENAB) ? 4 : 1,
796 			"%s busy, csr %04x\n",
797 			musb_ep->end_point.name, csr);
798 		goto done;
799 	}
800 
801 	if (dma && (csr & MUSB_RXCSR_DMAENAB)) {
802 		csr &= ~(MUSB_RXCSR_AUTOCLEAR
803 				| MUSB_RXCSR_DMAENAB
804 				| MUSB_RXCSR_DMAMODE);
805 		musb_writew(epio, MUSB_RXCSR,
806 			MUSB_RXCSR_P_WZC_BITS | csr);
807 
808 		request->actual += musb_ep->dma->actual_len;
809 
810 		DBG(4, "RXCSR%d %04x, dma off, %04x, len %zu, req %p\n",
811 			epnum, csr,
812 			musb_readw(epio, MUSB_RXCSR),
813 			musb_ep->dma->actual_len, request);
814 
815 #if defined(CONFIG_USB_INVENTRA_DMA) || defined(CONFIG_USB_TUSB_OMAP_DMA)
816 		/* Autoclear doesn't clear RxPktRdy for short packets */
817 		if ((dma->desired_mode == 0)
818 				|| (dma->actual_len
819 					& (musb_ep->packet_sz - 1))) {
820 			/* ack the read! */
821 			csr &= ~MUSB_RXCSR_RXPKTRDY;
822 			musb_writew(epio, MUSB_RXCSR, csr);
823 		}
824 
825 		/* incomplete, and not short? wait for next IN packet */
826 		if ((request->actual < request->length)
827 				&& (musb_ep->dma->actual_len
828 					== musb_ep->packet_sz))
829 			goto done;
830 #endif
831 		musb_g_giveback(musb_ep, request, 0);
832 
833 		request = next_request(musb_ep);
834 		if (!request)
835 			goto done;
836 
837 		/* don't start more i/o till the stall clears */
838 		musb_ep_select(mbase, epnum);
839 		csr = musb_readw(epio, MUSB_RXCSR);
840 		if (csr & MUSB_RXCSR_P_SENDSTALL)
841 			goto done;
842 	}
843 
844 
845 	/* analyze request if the ep is hot */
846 	if (request)
847 		rxstate(musb, to_musb_request(request));
848 	else
849 		DBG(3, "packet waiting for %s%s request\n",
850 				musb_ep->desc ? "" : "inactive ",
851 				musb_ep->end_point.name);
852 
853 done:
854 	return;
855 }
856 
857 /* ------------------------------------------------------------ */
858 
859 static int musb_gadget_enable(struct usb_ep *ep,
860 			const struct usb_endpoint_descriptor *desc)
861 {
862 	unsigned long		flags;
863 	struct musb_ep		*musb_ep;
864 	struct musb_hw_ep	*hw_ep;
865 	void __iomem		*regs;
866 	struct musb		*musb;
867 	void __iomem	*mbase;
868 	u8		epnum;
869 	u16		csr;
870 	unsigned	tmp;
871 	int		status = -EINVAL;
872 
873 	if (!ep || !desc)
874 		return -EINVAL;
875 
876 	musb_ep = to_musb_ep(ep);
877 	hw_ep = musb_ep->hw_ep;
878 	regs = hw_ep->regs;
879 	musb = musb_ep->musb;
880 	mbase = musb->mregs;
881 	epnum = musb_ep->current_epnum;
882 
883 	spin_lock_irqsave(&musb->lock, flags);
884 
885 	if (musb_ep->desc) {
886 		status = -EBUSY;
887 		goto fail;
888 	}
889 	musb_ep->type = usb_endpoint_type(desc);
890 
891 	/* check direction and (later) maxpacket size against endpoint */
892 	if (usb_endpoint_num(desc) != epnum)
893 		goto fail;
894 
895 	/* REVISIT this rules out high bandwidth periodic transfers */
896 	tmp = le16_to_cpu(desc->wMaxPacketSize);
897 	if (tmp & ~0x07ff)
898 		goto fail;
899 	musb_ep->packet_sz = tmp;
900 
901 	/* enable the interrupts for the endpoint, set the endpoint
902 	 * packet size (or fail), set the mode, clear the fifo
903 	 */
904 	musb_ep_select(mbase, epnum);
905 	if (usb_endpoint_dir_in(desc)) {
906 		u16 int_txe = musb_readw(mbase, MUSB_INTRTXE);
907 
908 		if (hw_ep->is_shared_fifo)
909 			musb_ep->is_in = 1;
910 		if (!musb_ep->is_in)
911 			goto fail;
912 		if (tmp > hw_ep->max_packet_sz_tx)
913 			goto fail;
914 
915 		int_txe |= (1 << epnum);
916 		musb_writew(mbase, MUSB_INTRTXE, int_txe);
917 
918 		/* REVISIT if can_bulk_split(), use by updating "tmp";
919 		 * likewise high bandwidth periodic tx
920 		 */
921 		musb_writew(regs, MUSB_TXMAXP, tmp);
922 
923 		csr = MUSB_TXCSR_MODE | MUSB_TXCSR_CLRDATATOG;
924 		if (musb_readw(regs, MUSB_TXCSR)
925 				& MUSB_TXCSR_FIFONOTEMPTY)
926 			csr |= MUSB_TXCSR_FLUSHFIFO;
927 		if (musb_ep->type == USB_ENDPOINT_XFER_ISOC)
928 			csr |= MUSB_TXCSR_P_ISO;
929 
930 		/* set twice in case of double buffering */
931 		musb_writew(regs, MUSB_TXCSR, csr);
932 		/* REVISIT may be inappropriate w/o FIFONOTEMPTY ... */
933 		musb_writew(regs, MUSB_TXCSR, csr);
934 
935 	} else {
936 		u16 int_rxe = musb_readw(mbase, MUSB_INTRRXE);
937 
938 		if (hw_ep->is_shared_fifo)
939 			musb_ep->is_in = 0;
940 		if (musb_ep->is_in)
941 			goto fail;
942 		if (tmp > hw_ep->max_packet_sz_rx)
943 			goto fail;
944 
945 		int_rxe |= (1 << epnum);
946 		musb_writew(mbase, MUSB_INTRRXE, int_rxe);
947 
948 		/* REVISIT if can_bulk_combine() use by updating "tmp"
949 		 * likewise high bandwidth periodic rx
950 		 */
951 		musb_writew(regs, MUSB_RXMAXP, tmp);
952 
953 		/* force shared fifo to OUT-only mode */
954 		if (hw_ep->is_shared_fifo) {
955 			csr = musb_readw(regs, MUSB_TXCSR);
956 			csr &= ~(MUSB_TXCSR_MODE | MUSB_TXCSR_TXPKTRDY);
957 			musb_writew(regs, MUSB_TXCSR, csr);
958 		}
959 
960 		csr = MUSB_RXCSR_FLUSHFIFO | MUSB_RXCSR_CLRDATATOG;
961 		if (musb_ep->type == USB_ENDPOINT_XFER_ISOC)
962 			csr |= MUSB_RXCSR_P_ISO;
963 		else if (musb_ep->type == USB_ENDPOINT_XFER_INT)
964 			csr |= MUSB_RXCSR_DISNYET;
965 
966 		/* set twice in case of double buffering */
967 		musb_writew(regs, MUSB_RXCSR, csr);
968 		musb_writew(regs, MUSB_RXCSR, csr);
969 	}
970 
971 	/* NOTE:  all the I/O code _should_ work fine without DMA, in case
972 	 * for some reason you run out of channels here.
973 	 */
974 	if (is_dma_capable() && musb->dma_controller) {
975 		struct dma_controller	*c = musb->dma_controller;
976 
977 		musb_ep->dma = c->channel_alloc(c, hw_ep,
978 				(desc->bEndpointAddress & USB_DIR_IN));
979 	} else
980 		musb_ep->dma = NULL;
981 
982 	musb_ep->desc = desc;
983 	musb_ep->busy = 0;
984 	status = 0;
985 
986 	pr_debug("%s periph: enabled %s for %s %s, %smaxpacket %d\n",
987 			musb_driver_name, musb_ep->end_point.name,
988 			({ char *s; switch (musb_ep->type) {
989 			case USB_ENDPOINT_XFER_BULK:	s = "bulk"; break;
990 			case USB_ENDPOINT_XFER_INT:	s = "int"; break;
991 			default:			s = "iso"; break;
992 			}; s; }),
993 			musb_ep->is_in ? "IN" : "OUT",
994 			musb_ep->dma ? "dma, " : "",
995 			musb_ep->packet_sz);
996 
997 	schedule_work(&musb->irq_work);
998 
999 fail:
1000 	spin_unlock_irqrestore(&musb->lock, flags);
1001 	return status;
1002 }
1003 
1004 /*
1005  * Disable an endpoint flushing all requests queued.
1006  */
1007 static int musb_gadget_disable(struct usb_ep *ep)
1008 {
1009 	unsigned long	flags;
1010 	struct musb	*musb;
1011 	u8		epnum;
1012 	struct musb_ep	*musb_ep;
1013 	void __iomem	*epio;
1014 	int		status = 0;
1015 
1016 	musb_ep = to_musb_ep(ep);
1017 	musb = musb_ep->musb;
1018 	epnum = musb_ep->current_epnum;
1019 	epio = musb->endpoints[epnum].regs;
1020 
1021 	spin_lock_irqsave(&musb->lock, flags);
1022 	musb_ep_select(musb->mregs, epnum);
1023 
1024 	/* zero the endpoint sizes */
1025 	if (musb_ep->is_in) {
1026 		u16 int_txe = musb_readw(musb->mregs, MUSB_INTRTXE);
1027 		int_txe &= ~(1 << epnum);
1028 		musb_writew(musb->mregs, MUSB_INTRTXE, int_txe);
1029 		musb_writew(epio, MUSB_TXMAXP, 0);
1030 	} else {
1031 		u16 int_rxe = musb_readw(musb->mregs, MUSB_INTRRXE);
1032 		int_rxe &= ~(1 << epnum);
1033 		musb_writew(musb->mregs, MUSB_INTRRXE, int_rxe);
1034 		musb_writew(epio, MUSB_RXMAXP, 0);
1035 	}
1036 
1037 	musb_ep->desc = NULL;
1038 
1039 	/* abort all pending DMA and requests */
1040 	nuke(musb_ep, -ESHUTDOWN);
1041 
1042 	schedule_work(&musb->irq_work);
1043 
1044 	spin_unlock_irqrestore(&(musb->lock), flags);
1045 
1046 	DBG(2, "%s\n", musb_ep->end_point.name);
1047 
1048 	return status;
1049 }
1050 
1051 /*
1052  * Allocate a request for an endpoint.
1053  * Reused by ep0 code.
1054  */
1055 struct usb_request *musb_alloc_request(struct usb_ep *ep, gfp_t gfp_flags)
1056 {
1057 	struct musb_ep		*musb_ep = to_musb_ep(ep);
1058 	struct musb_request	*request = NULL;
1059 
1060 	request = kzalloc(sizeof *request, gfp_flags);
1061 	if (request) {
1062 		INIT_LIST_HEAD(&request->request.list);
1063 		request->request.dma = DMA_ADDR_INVALID;
1064 		request->epnum = musb_ep->current_epnum;
1065 		request->ep = musb_ep;
1066 	}
1067 
1068 	return &request->request;
1069 }
1070 
1071 /*
1072  * Free a request
1073  * Reused by ep0 code.
1074  */
1075 void musb_free_request(struct usb_ep *ep, struct usb_request *req)
1076 {
1077 	kfree(to_musb_request(req));
1078 }
1079 
1080 static LIST_HEAD(buffers);
1081 
1082 struct free_record {
1083 	struct list_head	list;
1084 	struct device		*dev;
1085 	unsigned		bytes;
1086 	dma_addr_t		dma;
1087 };
1088 
1089 /*
1090  * Context: controller locked, IRQs blocked.
1091  */
1092 static void musb_ep_restart(struct musb *musb, struct musb_request *req)
1093 {
1094 	DBG(3, "<== %s request %p len %u on hw_ep%d\n",
1095 		req->tx ? "TX/IN" : "RX/OUT",
1096 		&req->request, req->request.length, req->epnum);
1097 
1098 	musb_ep_select(musb->mregs, req->epnum);
1099 	if (req->tx)
1100 		txstate(musb, req);
1101 	else
1102 		rxstate(musb, req);
1103 }
1104 
1105 static int musb_gadget_queue(struct usb_ep *ep, struct usb_request *req,
1106 			gfp_t gfp_flags)
1107 {
1108 	struct musb_ep		*musb_ep;
1109 	struct musb_request	*request;
1110 	struct musb		*musb;
1111 	int			status = 0;
1112 	unsigned long		lockflags;
1113 
1114 	if (!ep || !req)
1115 		return -EINVAL;
1116 	if (!req->buf)
1117 		return -ENODATA;
1118 
1119 	musb_ep = to_musb_ep(ep);
1120 	musb = musb_ep->musb;
1121 
1122 	request = to_musb_request(req);
1123 	request->musb = musb;
1124 
1125 	if (request->ep != musb_ep)
1126 		return -EINVAL;
1127 
1128 	DBG(4, "<== to %s request=%p\n", ep->name, req);
1129 
1130 	/* request is mine now... */
1131 	request->request.actual = 0;
1132 	request->request.status = -EINPROGRESS;
1133 	request->epnum = musb_ep->current_epnum;
1134 	request->tx = musb_ep->is_in;
1135 
1136 	if (is_dma_capable() && musb_ep->dma) {
1137 		if (request->request.dma == DMA_ADDR_INVALID) {
1138 			request->request.dma = dma_map_single(
1139 					musb->controller,
1140 					request->request.buf,
1141 					request->request.length,
1142 					request->tx
1143 						? DMA_TO_DEVICE
1144 						: DMA_FROM_DEVICE);
1145 			request->mapped = 1;
1146 		} else {
1147 			dma_sync_single_for_device(musb->controller,
1148 					request->request.dma,
1149 					request->request.length,
1150 					request->tx
1151 						? DMA_TO_DEVICE
1152 						: DMA_FROM_DEVICE);
1153 			request->mapped = 0;
1154 		}
1155 	} else if (!req->buf) {
1156 		return -ENODATA;
1157 	} else
1158 		request->mapped = 0;
1159 
1160 	spin_lock_irqsave(&musb->lock, lockflags);
1161 
1162 	/* don't queue if the ep is down */
1163 	if (!musb_ep->desc) {
1164 		DBG(4, "req %p queued to %s while ep %s\n",
1165 				req, ep->name, "disabled");
1166 		status = -ESHUTDOWN;
1167 		goto cleanup;
1168 	}
1169 
1170 	/* add request to the list */
1171 	list_add_tail(&(request->request.list), &(musb_ep->req_list));
1172 
1173 	/* it this is the head of the queue, start i/o ... */
1174 	if (!musb_ep->busy && &request->request.list == musb_ep->req_list.next)
1175 		musb_ep_restart(musb, request);
1176 
1177 cleanup:
1178 	spin_unlock_irqrestore(&musb->lock, lockflags);
1179 	return status;
1180 }
1181 
1182 static int musb_gadget_dequeue(struct usb_ep *ep, struct usb_request *request)
1183 {
1184 	struct musb_ep		*musb_ep = to_musb_ep(ep);
1185 	struct usb_request	*r;
1186 	unsigned long		flags;
1187 	int			status = 0;
1188 	struct musb		*musb = musb_ep->musb;
1189 
1190 	if (!ep || !request || to_musb_request(request)->ep != musb_ep)
1191 		return -EINVAL;
1192 
1193 	spin_lock_irqsave(&musb->lock, flags);
1194 
1195 	list_for_each_entry(r, &musb_ep->req_list, list) {
1196 		if (r == request)
1197 			break;
1198 	}
1199 	if (r != request) {
1200 		DBG(3, "request %p not queued to %s\n", request, ep->name);
1201 		status = -EINVAL;
1202 		goto done;
1203 	}
1204 
1205 	/* if the hardware doesn't have the request, easy ... */
1206 	if (musb_ep->req_list.next != &request->list || musb_ep->busy)
1207 		musb_g_giveback(musb_ep, request, -ECONNRESET);
1208 
1209 	/* ... else abort the dma transfer ... */
1210 	else if (is_dma_capable() && musb_ep->dma) {
1211 		struct dma_controller	*c = musb->dma_controller;
1212 
1213 		musb_ep_select(musb->mregs, musb_ep->current_epnum);
1214 		if (c->channel_abort)
1215 			status = c->channel_abort(musb_ep->dma);
1216 		else
1217 			status = -EBUSY;
1218 		if (status == 0)
1219 			musb_g_giveback(musb_ep, request, -ECONNRESET);
1220 	} else {
1221 		/* NOTE: by sticking to easily tested hardware/driver states,
1222 		 * we leave counting of in-flight packets imprecise.
1223 		 */
1224 		musb_g_giveback(musb_ep, request, -ECONNRESET);
1225 	}
1226 
1227 done:
1228 	spin_unlock_irqrestore(&musb->lock, flags);
1229 	return status;
1230 }
1231 
1232 /*
1233  * Set or clear the halt bit of an endpoint. A halted enpoint won't tx/rx any
1234  * data but will queue requests.
1235  *
1236  * exported to ep0 code
1237  */
1238 int musb_gadget_set_halt(struct usb_ep *ep, int value)
1239 {
1240 	struct musb_ep		*musb_ep = to_musb_ep(ep);
1241 	u8			epnum = musb_ep->current_epnum;
1242 	struct musb		*musb = musb_ep->musb;
1243 	void __iomem		*epio = musb->endpoints[epnum].regs;
1244 	void __iomem		*mbase;
1245 	unsigned long		flags;
1246 	u16			csr;
1247 	struct musb_request	*request = NULL;
1248 	int			status = 0;
1249 
1250 	if (!ep)
1251 		return -EINVAL;
1252 	mbase = musb->mregs;
1253 
1254 	spin_lock_irqsave(&musb->lock, flags);
1255 
1256 	if ((USB_ENDPOINT_XFER_ISOC == musb_ep->type)) {
1257 		status = -EINVAL;
1258 		goto done;
1259 	}
1260 
1261 	musb_ep_select(mbase, epnum);
1262 
1263 	/* cannot portably stall with non-empty FIFO */
1264 	request = to_musb_request(next_request(musb_ep));
1265 	if (value && musb_ep->is_in) {
1266 		csr = musb_readw(epio, MUSB_TXCSR);
1267 		if (csr & MUSB_TXCSR_FIFONOTEMPTY) {
1268 			DBG(3, "%s fifo busy, cannot halt\n", ep->name);
1269 			spin_unlock_irqrestore(&musb->lock, flags);
1270 			return -EAGAIN;
1271 		}
1272 
1273 	}
1274 
1275 	/* set/clear the stall and toggle bits */
1276 	DBG(2, "%s: %s stall\n", ep->name, value ? "set" : "clear");
1277 	if (musb_ep->is_in) {
1278 		csr = musb_readw(epio, MUSB_TXCSR);
1279 		if (csr & MUSB_TXCSR_FIFONOTEMPTY)
1280 			csr |= MUSB_TXCSR_FLUSHFIFO;
1281 		csr |= MUSB_TXCSR_P_WZC_BITS
1282 			| MUSB_TXCSR_CLRDATATOG;
1283 		if (value)
1284 			csr |= MUSB_TXCSR_P_SENDSTALL;
1285 		else
1286 			csr &= ~(MUSB_TXCSR_P_SENDSTALL
1287 				| MUSB_TXCSR_P_SENTSTALL);
1288 		csr &= ~MUSB_TXCSR_TXPKTRDY;
1289 		musb_writew(epio, MUSB_TXCSR, csr);
1290 	} else {
1291 		csr = musb_readw(epio, MUSB_RXCSR);
1292 		csr |= MUSB_RXCSR_P_WZC_BITS
1293 			| MUSB_RXCSR_FLUSHFIFO
1294 			| MUSB_RXCSR_CLRDATATOG;
1295 		if (value)
1296 			csr |= MUSB_RXCSR_P_SENDSTALL;
1297 		else
1298 			csr &= ~(MUSB_RXCSR_P_SENDSTALL
1299 				| MUSB_RXCSR_P_SENTSTALL);
1300 		musb_writew(epio, MUSB_RXCSR, csr);
1301 	}
1302 
1303 done:
1304 
1305 	/* maybe start the first request in the queue */
1306 	if (!musb_ep->busy && !value && request) {
1307 		DBG(3, "restarting the request\n");
1308 		musb_ep_restart(musb, request);
1309 	}
1310 
1311 	spin_unlock_irqrestore(&musb->lock, flags);
1312 	return status;
1313 }
1314 
1315 static int musb_gadget_fifo_status(struct usb_ep *ep)
1316 {
1317 	struct musb_ep		*musb_ep = to_musb_ep(ep);
1318 	void __iomem		*epio = musb_ep->hw_ep->regs;
1319 	int			retval = -EINVAL;
1320 
1321 	if (musb_ep->desc && !musb_ep->is_in) {
1322 		struct musb		*musb = musb_ep->musb;
1323 		int			epnum = musb_ep->current_epnum;
1324 		void __iomem		*mbase = musb->mregs;
1325 		unsigned long		flags;
1326 
1327 		spin_lock_irqsave(&musb->lock, flags);
1328 
1329 		musb_ep_select(mbase, epnum);
1330 		/* FIXME return zero unless RXPKTRDY is set */
1331 		retval = musb_readw(epio, MUSB_RXCOUNT);
1332 
1333 		spin_unlock_irqrestore(&musb->lock, flags);
1334 	}
1335 	return retval;
1336 }
1337 
1338 static void musb_gadget_fifo_flush(struct usb_ep *ep)
1339 {
1340 	struct musb_ep	*musb_ep = to_musb_ep(ep);
1341 	struct musb	*musb = musb_ep->musb;
1342 	u8		epnum = musb_ep->current_epnum;
1343 	void __iomem	*epio = musb->endpoints[epnum].regs;
1344 	void __iomem	*mbase;
1345 	unsigned long	flags;
1346 	u16		csr, int_txe;
1347 
1348 	mbase = musb->mregs;
1349 
1350 	spin_lock_irqsave(&musb->lock, flags);
1351 	musb_ep_select(mbase, (u8) epnum);
1352 
1353 	/* disable interrupts */
1354 	int_txe = musb_readw(mbase, MUSB_INTRTXE);
1355 	musb_writew(mbase, MUSB_INTRTXE, int_txe & ~(1 << epnum));
1356 
1357 	if (musb_ep->is_in) {
1358 		csr = musb_readw(epio, MUSB_TXCSR);
1359 		if (csr & MUSB_TXCSR_FIFONOTEMPTY) {
1360 			csr |= MUSB_TXCSR_FLUSHFIFO | MUSB_TXCSR_P_WZC_BITS;
1361 			musb_writew(epio, MUSB_TXCSR, csr);
1362 			/* REVISIT may be inappropriate w/o FIFONOTEMPTY ... */
1363 			musb_writew(epio, MUSB_TXCSR, csr);
1364 		}
1365 	} else {
1366 		csr = musb_readw(epio, MUSB_RXCSR);
1367 		csr |= MUSB_RXCSR_FLUSHFIFO | MUSB_RXCSR_P_WZC_BITS;
1368 		musb_writew(epio, MUSB_RXCSR, csr);
1369 		musb_writew(epio, MUSB_RXCSR, csr);
1370 	}
1371 
1372 	/* re-enable interrupt */
1373 	musb_writew(mbase, MUSB_INTRTXE, int_txe);
1374 	spin_unlock_irqrestore(&musb->lock, flags);
1375 }
1376 
1377 static const struct usb_ep_ops musb_ep_ops = {
1378 	.enable		= musb_gadget_enable,
1379 	.disable	= musb_gadget_disable,
1380 	.alloc_request	= musb_alloc_request,
1381 	.free_request	= musb_free_request,
1382 	.queue		= musb_gadget_queue,
1383 	.dequeue	= musb_gadget_dequeue,
1384 	.set_halt	= musb_gadget_set_halt,
1385 	.fifo_status	= musb_gadget_fifo_status,
1386 	.fifo_flush	= musb_gadget_fifo_flush
1387 };
1388 
1389 /* ----------------------------------------------------------------------- */
1390 
1391 static int musb_gadget_get_frame(struct usb_gadget *gadget)
1392 {
1393 	struct musb	*musb = gadget_to_musb(gadget);
1394 
1395 	return (int)musb_readw(musb->mregs, MUSB_FRAME);
1396 }
1397 
1398 static int musb_gadget_wakeup(struct usb_gadget *gadget)
1399 {
1400 	struct musb	*musb = gadget_to_musb(gadget);
1401 	void __iomem	*mregs = musb->mregs;
1402 	unsigned long	flags;
1403 	int		status = -EINVAL;
1404 	u8		power, devctl;
1405 	int		retries;
1406 
1407 	spin_lock_irqsave(&musb->lock, flags);
1408 
1409 	switch (musb->xceiv->state) {
1410 	case OTG_STATE_B_PERIPHERAL:
1411 		/* NOTE:  OTG state machine doesn't include B_SUSPENDED;
1412 		 * that's part of the standard usb 1.1 state machine, and
1413 		 * doesn't affect OTG transitions.
1414 		 */
1415 		if (musb->may_wakeup && musb->is_suspended)
1416 			break;
1417 		goto done;
1418 	case OTG_STATE_B_IDLE:
1419 		/* Start SRP ... OTG not required. */
1420 		devctl = musb_readb(mregs, MUSB_DEVCTL);
1421 		DBG(2, "Sending SRP: devctl: %02x\n", devctl);
1422 		devctl |= MUSB_DEVCTL_SESSION;
1423 		musb_writeb(mregs, MUSB_DEVCTL, devctl);
1424 		devctl = musb_readb(mregs, MUSB_DEVCTL);
1425 		retries = 100;
1426 		while (!(devctl & MUSB_DEVCTL_SESSION)) {
1427 			devctl = musb_readb(mregs, MUSB_DEVCTL);
1428 			if (retries-- < 1)
1429 				break;
1430 		}
1431 		retries = 10000;
1432 		while (devctl & MUSB_DEVCTL_SESSION) {
1433 			devctl = musb_readb(mregs, MUSB_DEVCTL);
1434 			if (retries-- < 1)
1435 				break;
1436 		}
1437 
1438 		/* Block idling for at least 1s */
1439 		musb_platform_try_idle(musb,
1440 			jiffies + msecs_to_jiffies(1 * HZ));
1441 
1442 		status = 0;
1443 		goto done;
1444 	default:
1445 		DBG(2, "Unhandled wake: %s\n", otg_state_string(musb));
1446 		goto done;
1447 	}
1448 
1449 	status = 0;
1450 
1451 	power = musb_readb(mregs, MUSB_POWER);
1452 	power |= MUSB_POWER_RESUME;
1453 	musb_writeb(mregs, MUSB_POWER, power);
1454 	DBG(2, "issue wakeup\n");
1455 
1456 	/* FIXME do this next chunk in a timer callback, no udelay */
1457 	mdelay(2);
1458 
1459 	power = musb_readb(mregs, MUSB_POWER);
1460 	power &= ~MUSB_POWER_RESUME;
1461 	musb_writeb(mregs, MUSB_POWER, power);
1462 done:
1463 	spin_unlock_irqrestore(&musb->lock, flags);
1464 	return status;
1465 }
1466 
1467 static int
1468 musb_gadget_set_self_powered(struct usb_gadget *gadget, int is_selfpowered)
1469 {
1470 	struct musb	*musb = gadget_to_musb(gadget);
1471 
1472 	musb->is_self_powered = !!is_selfpowered;
1473 	return 0;
1474 }
1475 
1476 static void musb_pullup(struct musb *musb, int is_on)
1477 {
1478 	u8 power;
1479 
1480 	power = musb_readb(musb->mregs, MUSB_POWER);
1481 	if (is_on)
1482 		power |= MUSB_POWER_SOFTCONN;
1483 	else
1484 		power &= ~MUSB_POWER_SOFTCONN;
1485 
1486 	/* FIXME if on, HdrcStart; if off, HdrcStop */
1487 
1488 	DBG(3, "gadget %s D+ pullup %s\n",
1489 		musb->gadget_driver->function, is_on ? "on" : "off");
1490 	musb_writeb(musb->mregs, MUSB_POWER, power);
1491 }
1492 
1493 #if 0
1494 static int musb_gadget_vbus_session(struct usb_gadget *gadget, int is_active)
1495 {
1496 	DBG(2, "<= %s =>\n", __func__);
1497 
1498 	/*
1499 	 * FIXME iff driver's softconnect flag is set (as it is during probe,
1500 	 * though that can clear it), just musb_pullup().
1501 	 */
1502 
1503 	return -EINVAL;
1504 }
1505 #endif
1506 
1507 static int musb_gadget_vbus_draw(struct usb_gadget *gadget, unsigned mA)
1508 {
1509 	struct musb	*musb = gadget_to_musb(gadget);
1510 
1511 	if (!musb->xceiv->set_power)
1512 		return -EOPNOTSUPP;
1513 	return otg_set_power(musb->xceiv, mA);
1514 }
1515 
1516 static int musb_gadget_pullup(struct usb_gadget *gadget, int is_on)
1517 {
1518 	struct musb	*musb = gadget_to_musb(gadget);
1519 	unsigned long	flags;
1520 
1521 	is_on = !!is_on;
1522 
1523 	/* NOTE: this assumes we are sensing vbus; we'd rather
1524 	 * not pullup unless the B-session is active.
1525 	 */
1526 	spin_lock_irqsave(&musb->lock, flags);
1527 	if (is_on != musb->softconnect) {
1528 		musb->softconnect = is_on;
1529 		musb_pullup(musb, is_on);
1530 	}
1531 	spin_unlock_irqrestore(&musb->lock, flags);
1532 	return 0;
1533 }
1534 
1535 static const struct usb_gadget_ops musb_gadget_operations = {
1536 	.get_frame		= musb_gadget_get_frame,
1537 	.wakeup			= musb_gadget_wakeup,
1538 	.set_selfpowered	= musb_gadget_set_self_powered,
1539 	/* .vbus_session		= musb_gadget_vbus_session, */
1540 	.vbus_draw		= musb_gadget_vbus_draw,
1541 	.pullup			= musb_gadget_pullup,
1542 };
1543 
1544 /* ----------------------------------------------------------------------- */
1545 
1546 /* Registration */
1547 
1548 /* Only this registration code "knows" the rule (from USB standards)
1549  * about there being only one external upstream port.  It assumes
1550  * all peripheral ports are external...
1551  */
1552 static struct musb *the_gadget;
1553 
1554 static void musb_gadget_release(struct device *dev)
1555 {
1556 	/* kref_put(WHAT) */
1557 	dev_dbg(dev, "%s\n", __func__);
1558 }
1559 
1560 
1561 static void __init
1562 init_peripheral_ep(struct musb *musb, struct musb_ep *ep, u8 epnum, int is_in)
1563 {
1564 	struct musb_hw_ep	*hw_ep = musb->endpoints + epnum;
1565 
1566 	memset(ep, 0, sizeof *ep);
1567 
1568 	ep->current_epnum = epnum;
1569 	ep->musb = musb;
1570 	ep->hw_ep = hw_ep;
1571 	ep->is_in = is_in;
1572 
1573 	INIT_LIST_HEAD(&ep->req_list);
1574 
1575 	sprintf(ep->name, "ep%d%s", epnum,
1576 			(!epnum || hw_ep->is_shared_fifo) ? "" : (
1577 				is_in ? "in" : "out"));
1578 	ep->end_point.name = ep->name;
1579 	INIT_LIST_HEAD(&ep->end_point.ep_list);
1580 	if (!epnum) {
1581 		ep->end_point.maxpacket = 64;
1582 		ep->end_point.ops = &musb_g_ep0_ops;
1583 		musb->g.ep0 = &ep->end_point;
1584 	} else {
1585 		if (is_in)
1586 			ep->end_point.maxpacket = hw_ep->max_packet_sz_tx;
1587 		else
1588 			ep->end_point.maxpacket = hw_ep->max_packet_sz_rx;
1589 		ep->end_point.ops = &musb_ep_ops;
1590 		list_add_tail(&ep->end_point.ep_list, &musb->g.ep_list);
1591 	}
1592 }
1593 
1594 /*
1595  * Initialize the endpoints exposed to peripheral drivers, with backlinks
1596  * to the rest of the driver state.
1597  */
1598 static inline void __init musb_g_init_endpoints(struct musb *musb)
1599 {
1600 	u8			epnum;
1601 	struct musb_hw_ep	*hw_ep;
1602 	unsigned		count = 0;
1603 
1604 	/* intialize endpoint list just once */
1605 	INIT_LIST_HEAD(&(musb->g.ep_list));
1606 
1607 	for (epnum = 0, hw_ep = musb->endpoints;
1608 			epnum < musb->nr_endpoints;
1609 			epnum++, hw_ep++) {
1610 		if (hw_ep->is_shared_fifo /* || !epnum */) {
1611 			init_peripheral_ep(musb, &hw_ep->ep_in, epnum, 0);
1612 			count++;
1613 		} else {
1614 			if (hw_ep->max_packet_sz_tx) {
1615 				init_peripheral_ep(musb, &hw_ep->ep_in,
1616 							epnum, 1);
1617 				count++;
1618 			}
1619 			if (hw_ep->max_packet_sz_rx) {
1620 				init_peripheral_ep(musb, &hw_ep->ep_out,
1621 							epnum, 0);
1622 				count++;
1623 			}
1624 		}
1625 	}
1626 }
1627 
1628 /* called once during driver setup to initialize and link into
1629  * the driver model; memory is zeroed.
1630  */
1631 int __init musb_gadget_setup(struct musb *musb)
1632 {
1633 	int status;
1634 
1635 	/* REVISIT minor race:  if (erroneously) setting up two
1636 	 * musb peripherals at the same time, only the bus lock
1637 	 * is probably held.
1638 	 */
1639 	if (the_gadget)
1640 		return -EBUSY;
1641 	the_gadget = musb;
1642 
1643 	musb->g.ops = &musb_gadget_operations;
1644 	musb->g.is_dualspeed = 1;
1645 	musb->g.speed = USB_SPEED_UNKNOWN;
1646 
1647 	/* this "gadget" abstracts/virtualizes the controller */
1648 	dev_set_name(&musb->g.dev, "gadget");
1649 	musb->g.dev.parent = musb->controller;
1650 	musb->g.dev.dma_mask = musb->controller->dma_mask;
1651 	musb->g.dev.release = musb_gadget_release;
1652 	musb->g.name = musb_driver_name;
1653 
1654 	if (is_otg_enabled(musb))
1655 		musb->g.is_otg = 1;
1656 
1657 	musb_g_init_endpoints(musb);
1658 
1659 	musb->is_active = 0;
1660 	musb_platform_try_idle(musb, 0);
1661 
1662 	status = device_register(&musb->g.dev);
1663 	if (status != 0)
1664 		the_gadget = NULL;
1665 	return status;
1666 }
1667 
1668 void musb_gadget_cleanup(struct musb *musb)
1669 {
1670 	if (musb != the_gadget)
1671 		return;
1672 
1673 	device_unregister(&musb->g.dev);
1674 	the_gadget = NULL;
1675 }
1676 
1677 /*
1678  * Register the gadget driver. Used by gadget drivers when
1679  * registering themselves with the controller.
1680  *
1681  * -EINVAL something went wrong (not driver)
1682  * -EBUSY another gadget is already using the controller
1683  * -ENOMEM no memeory to perform the operation
1684  *
1685  * @param driver the gadget driver
1686  * @return <0 if error, 0 if everything is fine
1687  */
1688 int usb_gadget_register_driver(struct usb_gadget_driver *driver)
1689 {
1690 	int retval;
1691 	unsigned long flags;
1692 	struct musb *musb = the_gadget;
1693 
1694 	if (!driver
1695 			|| driver->speed != USB_SPEED_HIGH
1696 			|| !driver->bind
1697 			|| !driver->setup)
1698 		return -EINVAL;
1699 
1700 	/* driver must be initialized to support peripheral mode */
1701 	if (!musb || !(musb->board_mode == MUSB_OTG
1702 				|| musb->board_mode != MUSB_OTG)) {
1703 		DBG(1, "%s, no dev??\n", __func__);
1704 		return -ENODEV;
1705 	}
1706 
1707 	DBG(3, "registering driver %s\n", driver->function);
1708 	spin_lock_irqsave(&musb->lock, flags);
1709 
1710 	if (musb->gadget_driver) {
1711 		DBG(1, "%s is already bound to %s\n",
1712 				musb_driver_name,
1713 				musb->gadget_driver->driver.name);
1714 		retval = -EBUSY;
1715 	} else {
1716 		musb->gadget_driver = driver;
1717 		musb->g.dev.driver = &driver->driver;
1718 		driver->driver.bus = NULL;
1719 		musb->softconnect = 1;
1720 		retval = 0;
1721 	}
1722 
1723 	spin_unlock_irqrestore(&musb->lock, flags);
1724 
1725 	if (retval == 0) {
1726 		retval = driver->bind(&musb->g);
1727 		if (retval != 0) {
1728 			DBG(3, "bind to driver %s failed --> %d\n",
1729 					driver->driver.name, retval);
1730 			musb->gadget_driver = NULL;
1731 			musb->g.dev.driver = NULL;
1732 		}
1733 
1734 		spin_lock_irqsave(&musb->lock, flags);
1735 
1736 		otg_set_peripheral(musb->xceiv, &musb->g);
1737 		musb->is_active = 1;
1738 
1739 		/* FIXME this ignores the softconnect flag.  Drivers are
1740 		 * allowed hold the peripheral inactive until for example
1741 		 * userspace hooks up printer hardware or DSP codecs, so
1742 		 * hosts only see fully functional devices.
1743 		 */
1744 
1745 		if (!is_otg_enabled(musb))
1746 			musb_start(musb);
1747 
1748 		otg_set_peripheral(musb->xceiv, &musb->g);
1749 
1750 		spin_unlock_irqrestore(&musb->lock, flags);
1751 
1752 		if (is_otg_enabled(musb)) {
1753 			DBG(3, "OTG startup...\n");
1754 
1755 			/* REVISIT:  funcall to other code, which also
1756 			 * handles power budgeting ... this way also
1757 			 * ensures HdrcStart is indirectly called.
1758 			 */
1759 			retval = usb_add_hcd(musb_to_hcd(musb), -1, 0);
1760 			if (retval < 0) {
1761 				DBG(1, "add_hcd failed, %d\n", retval);
1762 				spin_lock_irqsave(&musb->lock, flags);
1763 				otg_set_peripheral(musb->xceiv, NULL);
1764 				musb->gadget_driver = NULL;
1765 				musb->g.dev.driver = NULL;
1766 				spin_unlock_irqrestore(&musb->lock, flags);
1767 			}
1768 		}
1769 	}
1770 
1771 	return retval;
1772 }
1773 EXPORT_SYMBOL(usb_gadget_register_driver);
1774 
1775 static void stop_activity(struct musb *musb, struct usb_gadget_driver *driver)
1776 {
1777 	int			i;
1778 	struct musb_hw_ep	*hw_ep;
1779 
1780 	/* don't disconnect if it's not connected */
1781 	if (musb->g.speed == USB_SPEED_UNKNOWN)
1782 		driver = NULL;
1783 	else
1784 		musb->g.speed = USB_SPEED_UNKNOWN;
1785 
1786 	/* deactivate the hardware */
1787 	if (musb->softconnect) {
1788 		musb->softconnect = 0;
1789 		musb_pullup(musb, 0);
1790 	}
1791 	musb_stop(musb);
1792 
1793 	/* killing any outstanding requests will quiesce the driver;
1794 	 * then report disconnect
1795 	 */
1796 	if (driver) {
1797 		for (i = 0, hw_ep = musb->endpoints;
1798 				i < musb->nr_endpoints;
1799 				i++, hw_ep++) {
1800 			musb_ep_select(musb->mregs, i);
1801 			if (hw_ep->is_shared_fifo /* || !epnum */) {
1802 				nuke(&hw_ep->ep_in, -ESHUTDOWN);
1803 			} else {
1804 				if (hw_ep->max_packet_sz_tx)
1805 					nuke(&hw_ep->ep_in, -ESHUTDOWN);
1806 				if (hw_ep->max_packet_sz_rx)
1807 					nuke(&hw_ep->ep_out, -ESHUTDOWN);
1808 			}
1809 		}
1810 
1811 		spin_unlock(&musb->lock);
1812 		driver->disconnect(&musb->g);
1813 		spin_lock(&musb->lock);
1814 	}
1815 }
1816 
1817 /*
1818  * Unregister the gadget driver. Used by gadget drivers when
1819  * unregistering themselves from the controller.
1820  *
1821  * @param driver the gadget driver to unregister
1822  */
1823 int usb_gadget_unregister_driver(struct usb_gadget_driver *driver)
1824 {
1825 	unsigned long	flags;
1826 	int		retval = 0;
1827 	struct musb	*musb = the_gadget;
1828 
1829 	if (!driver || !driver->unbind || !musb)
1830 		return -EINVAL;
1831 
1832 	/* REVISIT always use otg_set_peripheral() here too;
1833 	 * this needs to shut down the OTG engine.
1834 	 */
1835 
1836 	spin_lock_irqsave(&musb->lock, flags);
1837 
1838 #ifdef	CONFIG_USB_MUSB_OTG
1839 	musb_hnp_stop(musb);
1840 #endif
1841 
1842 	if (musb->gadget_driver == driver) {
1843 
1844 		(void) musb_gadget_vbus_draw(&musb->g, 0);
1845 
1846 		musb->xceiv->state = OTG_STATE_UNDEFINED;
1847 		stop_activity(musb, driver);
1848 		otg_set_peripheral(musb->xceiv, NULL);
1849 
1850 		DBG(3, "unregistering driver %s\n", driver->function);
1851 		spin_unlock_irqrestore(&musb->lock, flags);
1852 		driver->unbind(&musb->g);
1853 		spin_lock_irqsave(&musb->lock, flags);
1854 
1855 		musb->gadget_driver = NULL;
1856 		musb->g.dev.driver = NULL;
1857 
1858 		musb->is_active = 0;
1859 		musb_platform_try_idle(musb, 0);
1860 	} else
1861 		retval = -EINVAL;
1862 	spin_unlock_irqrestore(&musb->lock, flags);
1863 
1864 	if (is_otg_enabled(musb) && retval == 0) {
1865 		usb_remove_hcd(musb_to_hcd(musb));
1866 		/* FIXME we need to be able to register another
1867 		 * gadget driver here and have everything work;
1868 		 * that currently misbehaves.
1869 		 */
1870 	}
1871 
1872 	return retval;
1873 }
1874 EXPORT_SYMBOL(usb_gadget_unregister_driver);
1875 
1876 
1877 /* ----------------------------------------------------------------------- */
1878 
1879 /* lifecycle operations called through plat_uds.c */
1880 
1881 void musb_g_resume(struct musb *musb)
1882 {
1883 	musb->is_suspended = 0;
1884 	switch (musb->xceiv->state) {
1885 	case OTG_STATE_B_IDLE:
1886 		break;
1887 	case OTG_STATE_B_WAIT_ACON:
1888 	case OTG_STATE_B_PERIPHERAL:
1889 		musb->is_active = 1;
1890 		if (musb->gadget_driver && musb->gadget_driver->resume) {
1891 			spin_unlock(&musb->lock);
1892 			musb->gadget_driver->resume(&musb->g);
1893 			spin_lock(&musb->lock);
1894 		}
1895 		break;
1896 	default:
1897 		WARNING("unhandled RESUME transition (%s)\n",
1898 				otg_state_string(musb));
1899 	}
1900 }
1901 
1902 /* called when SOF packets stop for 3+ msec */
1903 void musb_g_suspend(struct musb *musb)
1904 {
1905 	u8	devctl;
1906 
1907 	devctl = musb_readb(musb->mregs, MUSB_DEVCTL);
1908 	DBG(3, "devctl %02x\n", devctl);
1909 
1910 	switch (musb->xceiv->state) {
1911 	case OTG_STATE_B_IDLE:
1912 		if ((devctl & MUSB_DEVCTL_VBUS) == MUSB_DEVCTL_VBUS)
1913 			musb->xceiv->state = OTG_STATE_B_PERIPHERAL;
1914 		break;
1915 	case OTG_STATE_B_PERIPHERAL:
1916 		musb->is_suspended = 1;
1917 		if (musb->gadget_driver && musb->gadget_driver->suspend) {
1918 			spin_unlock(&musb->lock);
1919 			musb->gadget_driver->suspend(&musb->g);
1920 			spin_lock(&musb->lock);
1921 		}
1922 		break;
1923 	default:
1924 		/* REVISIT if B_HOST, clear DEVCTL.HOSTREQ;
1925 		 * A_PERIPHERAL may need care too
1926 		 */
1927 		WARNING("unhandled SUSPEND transition (%s)\n",
1928 				otg_state_string(musb));
1929 	}
1930 }
1931 
1932 /* Called during SRP */
1933 void musb_g_wakeup(struct musb *musb)
1934 {
1935 	musb_gadget_wakeup(&musb->g);
1936 }
1937 
1938 /* called when VBUS drops below session threshold, and in other cases */
1939 void musb_g_disconnect(struct musb *musb)
1940 {
1941 	void __iomem	*mregs = musb->mregs;
1942 	u8	devctl = musb_readb(mregs, MUSB_DEVCTL);
1943 
1944 	DBG(3, "devctl %02x\n", devctl);
1945 
1946 	/* clear HR */
1947 	musb_writeb(mregs, MUSB_DEVCTL, devctl & MUSB_DEVCTL_SESSION);
1948 
1949 	/* don't draw vbus until new b-default session */
1950 	(void) musb_gadget_vbus_draw(&musb->g, 0);
1951 
1952 	musb->g.speed = USB_SPEED_UNKNOWN;
1953 	if (musb->gadget_driver && musb->gadget_driver->disconnect) {
1954 		spin_unlock(&musb->lock);
1955 		musb->gadget_driver->disconnect(&musb->g);
1956 		spin_lock(&musb->lock);
1957 	}
1958 
1959 	switch (musb->xceiv->state) {
1960 	default:
1961 #ifdef	CONFIG_USB_MUSB_OTG
1962 		DBG(2, "Unhandled disconnect %s, setting a_idle\n",
1963 			otg_state_string(musb));
1964 		musb->xceiv->state = OTG_STATE_A_IDLE;
1965 		MUSB_HST_MODE(musb);
1966 		break;
1967 	case OTG_STATE_A_PERIPHERAL:
1968 		musb->xceiv->state = OTG_STATE_A_WAIT_BCON;
1969 		MUSB_HST_MODE(musb);
1970 		break;
1971 	case OTG_STATE_B_WAIT_ACON:
1972 	case OTG_STATE_B_HOST:
1973 #endif
1974 	case OTG_STATE_B_PERIPHERAL:
1975 	case OTG_STATE_B_IDLE:
1976 		musb->xceiv->state = OTG_STATE_B_IDLE;
1977 		break;
1978 	case OTG_STATE_B_SRP_INIT:
1979 		break;
1980 	}
1981 
1982 	musb->is_active = 0;
1983 }
1984 
1985 void musb_g_reset(struct musb *musb)
1986 __releases(musb->lock)
1987 __acquires(musb->lock)
1988 {
1989 	void __iomem	*mbase = musb->mregs;
1990 	u8		devctl = musb_readb(mbase, MUSB_DEVCTL);
1991 	u8		power;
1992 
1993 	DBG(3, "<== %s addr=%x driver '%s'\n",
1994 			(devctl & MUSB_DEVCTL_BDEVICE)
1995 				? "B-Device" : "A-Device",
1996 			musb_readb(mbase, MUSB_FADDR),
1997 			musb->gadget_driver
1998 				? musb->gadget_driver->driver.name
1999 				: NULL
2000 			);
2001 
2002 	/* report disconnect, if we didn't already (flushing EP state) */
2003 	if (musb->g.speed != USB_SPEED_UNKNOWN)
2004 		musb_g_disconnect(musb);
2005 
2006 	/* clear HR */
2007 	else if (devctl & MUSB_DEVCTL_HR)
2008 		musb_writeb(mbase, MUSB_DEVCTL, MUSB_DEVCTL_SESSION);
2009 
2010 
2011 	/* what speed did we negotiate? */
2012 	power = musb_readb(mbase, MUSB_POWER);
2013 	musb->g.speed = (power & MUSB_POWER_HSMODE)
2014 			? USB_SPEED_HIGH : USB_SPEED_FULL;
2015 
2016 	/* start in USB_STATE_DEFAULT */
2017 	musb->is_active = 1;
2018 	musb->is_suspended = 0;
2019 	MUSB_DEV_MODE(musb);
2020 	musb->address = 0;
2021 	musb->ep0_state = MUSB_EP0_STAGE_SETUP;
2022 
2023 	musb->may_wakeup = 0;
2024 	musb->g.b_hnp_enable = 0;
2025 	musb->g.a_alt_hnp_support = 0;
2026 	musb->g.a_hnp_support = 0;
2027 
2028 	/* Normal reset, as B-Device;
2029 	 * or else after HNP, as A-Device
2030 	 */
2031 	if (devctl & MUSB_DEVCTL_BDEVICE) {
2032 		musb->xceiv->state = OTG_STATE_B_PERIPHERAL;
2033 		musb->g.is_a_peripheral = 0;
2034 	} else if (is_otg_enabled(musb)) {
2035 		musb->xceiv->state = OTG_STATE_A_PERIPHERAL;
2036 		musb->g.is_a_peripheral = 1;
2037 	} else
2038 		WARN_ON(1);
2039 
2040 	/* start with default limits on VBUS power draw */
2041 	(void) musb_gadget_vbus_draw(&musb->g,
2042 			is_otg_enabled(musb) ? 8 : 100);
2043 }
2044