xref: /openbmc/linux/drivers/usb/musb/musb_gadget.c (revision a09d2831)
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  * Copyright (C) 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/kernel.h>
37 #include <linux/list.h>
38 #include <linux/timer.h>
39 #include <linux/module.h>
40 #include <linux/smp.h>
41 #include <linux/spinlock.h>
42 #include <linux/delay.h>
43 #include <linux/moduleparam.h>
44 #include <linux/stat.h>
45 #include <linux/dma-mapping.h>
46 
47 #include "musb_core.h"
48 
49 
50 /* MUSB PERIPHERAL status 3-mar-2006:
51  *
52  * - EP0 seems solid.  It passes both USBCV and usbtest control cases.
53  *   Minor glitches:
54  *
55  *     + remote wakeup to Linux hosts work, but saw USBCV failures;
56  *       in one test run (operator error?)
57  *     + endpoint halt tests -- in both usbtest and usbcv -- seem
58  *       to break when dma is enabled ... is something wrongly
59  *       clearing SENDSTALL?
60  *
61  * - Mass storage behaved ok when last tested.  Network traffic patterns
62  *   (with lots of short transfers etc) need retesting; they turn up the
63  *   worst cases of the DMA, since short packets are typical but are not
64  *   required.
65  *
66  * - TX/IN
67  *     + both pio and dma behave in with network and g_zero tests
68  *     + no cppi throughput issues other than no-hw-queueing
69  *     + failed with FLAT_REG (DaVinci)
70  *     + seems to behave with double buffering, PIO -and- CPPI
71  *     + with gadgetfs + AIO, requests got lost?
72  *
73  * - RX/OUT
74  *     + both pio and dma behave in with network and g_zero tests
75  *     + dma is slow in typical case (short_not_ok is clear)
76  *     + double buffering ok with PIO
77  *     + double buffering *FAILS* with CPPI, wrong data bytes sometimes
78  *     + request lossage observed with gadgetfs
79  *
80  * - ISO not tested ... might work, but only weakly isochronous
81  *
82  * - Gadget driver disabling of softconnect during bind() is ignored; so
83  *   drivers can't hold off host requests until userspace is ready.
84  *   (Workaround:  they can turn it off later.)
85  *
86  * - PORTABILITY (assumes PIO works):
87  *     + DaVinci, basically works with cppi dma
88  *     + OMAP 2430, ditto with mentor dma
89  *     + TUSB 6010, platform-specific dma in the works
90  */
91 
92 /* ----------------------------------------------------------------------- */
93 
94 /*
95  * Immediately complete a request.
96  *
97  * @param request the request to complete
98  * @param status the status to complete the request with
99  * Context: controller locked, IRQs blocked.
100  */
101 void musb_g_giveback(
102 	struct musb_ep		*ep,
103 	struct usb_request	*request,
104 	int			status)
105 __releases(ep->musb->lock)
106 __acquires(ep->musb->lock)
107 {
108 	struct musb_request	*req;
109 	struct musb		*musb;
110 	int			busy = ep->busy;
111 
112 	req = to_musb_request(request);
113 
114 	list_del(&request->list);
115 	if (req->request.status == -EINPROGRESS)
116 		req->request.status = status;
117 	musb = req->musb;
118 
119 	ep->busy = 1;
120 	spin_unlock(&musb->lock);
121 	if (is_dma_capable()) {
122 		if (req->mapped) {
123 			dma_unmap_single(musb->controller,
124 					req->request.dma,
125 					req->request.length,
126 					req->tx
127 						? DMA_TO_DEVICE
128 						: DMA_FROM_DEVICE);
129 			req->request.dma = DMA_ADDR_INVALID;
130 			req->mapped = 0;
131 		} else if (req->request.dma != DMA_ADDR_INVALID)
132 			dma_sync_single_for_cpu(musb->controller,
133 					req->request.dma,
134 					req->request.length,
135 					req->tx
136 						? DMA_TO_DEVICE
137 						: DMA_FROM_DEVICE);
138 	}
139 	if (request->status == 0)
140 		DBG(5, "%s done request %p,  %d/%d\n",
141 				ep->end_point.name, request,
142 				req->request.actual, req->request.length);
143 	else
144 		DBG(2, "%s request %p, %d/%d fault %d\n",
145 				ep->end_point.name, request,
146 				req->request.actual, req->request.length,
147 				request->status);
148 	req->request.complete(&req->ep->end_point, &req->request);
149 	spin_lock(&musb->lock);
150 	ep->busy = busy;
151 }
152 
153 /* ----------------------------------------------------------------------- */
154 
155 /*
156  * Abort requests queued to an endpoint using the status. Synchronous.
157  * caller locked controller and blocked irqs, and selected this ep.
158  */
159 static void nuke(struct musb_ep *ep, const int status)
160 {
161 	struct musb_request	*req = NULL;
162 	void __iomem *epio = ep->musb->endpoints[ep->current_epnum].regs;
163 
164 	ep->busy = 1;
165 
166 	if (is_dma_capable() && ep->dma) {
167 		struct dma_controller	*c = ep->musb->dma_controller;
168 		int value;
169 
170 		if (ep->is_in) {
171 			/*
172 			 * The programming guide says that we must not clear
173 			 * the DMAMODE bit before DMAENAB, so we only
174 			 * clear it in the second write...
175 			 */
176 			musb_writew(epio, MUSB_TXCSR,
177 				    MUSB_TXCSR_DMAMODE | MUSB_TXCSR_FLUSHFIFO);
178 			musb_writew(epio, MUSB_TXCSR,
179 					0 | MUSB_TXCSR_FLUSHFIFO);
180 		} else {
181 			musb_writew(epio, MUSB_RXCSR,
182 					0 | MUSB_RXCSR_FLUSHFIFO);
183 			musb_writew(epio, MUSB_RXCSR,
184 					0 | MUSB_RXCSR_FLUSHFIFO);
185 		}
186 
187 		value = c->channel_abort(ep->dma);
188 		DBG(value ? 1 : 6, "%s: abort DMA --> %d\n", ep->name, value);
189 		c->channel_release(ep->dma);
190 		ep->dma = NULL;
191 	}
192 
193 	while (!list_empty(&(ep->req_list))) {
194 		req = container_of(ep->req_list.next, struct musb_request,
195 				request.list);
196 		musb_g_giveback(ep, &req->request, status);
197 	}
198 }
199 
200 /* ----------------------------------------------------------------------- */
201 
202 /* Data transfers - pure PIO, pure DMA, or mixed mode */
203 
204 /*
205  * This assumes the separate CPPI engine is responding to DMA requests
206  * from the usb core ... sequenced a bit differently from mentor dma.
207  */
208 
209 static inline int max_ep_writesize(struct musb *musb, struct musb_ep *ep)
210 {
211 	if (can_bulk_split(musb, ep->type))
212 		return ep->hw_ep->max_packet_sz_tx;
213 	else
214 		return ep->packet_sz;
215 }
216 
217 
218 #ifdef CONFIG_USB_INVENTRA_DMA
219 
220 /* Peripheral tx (IN) using Mentor DMA works as follows:
221 	Only mode 0 is used for transfers <= wPktSize,
222 	mode 1 is used for larger transfers,
223 
224 	One of the following happens:
225 	- Host sends IN token which causes an endpoint interrupt
226 		-> TxAvail
227 			-> if DMA is currently busy, exit.
228 			-> if queue is non-empty, txstate().
229 
230 	- Request is queued by the gadget driver.
231 		-> if queue was previously empty, txstate()
232 
233 	txstate()
234 		-> start
235 		  /\	-> setup DMA
236 		  |     (data is transferred to the FIFO, then sent out when
237 		  |	IN token(s) are recd from Host.
238 		  |		-> DMA interrupt on completion
239 		  |		   calls TxAvail.
240 		  |		      -> stop DMA, ~DMAENAB,
241 		  |		      -> set TxPktRdy for last short pkt or zlp
242 		  |		      -> Complete Request
243 		  |		      -> Continue next request (call txstate)
244 		  |___________________________________|
245 
246  * Non-Mentor DMA engines can of course work differently, such as by
247  * upleveling from irq-per-packet to irq-per-buffer.
248  */
249 
250 #endif
251 
252 /*
253  * An endpoint is transmitting data. This can be called either from
254  * the IRQ routine or from ep.queue() to kickstart a request on an
255  * endpoint.
256  *
257  * Context: controller locked, IRQs blocked, endpoint selected
258  */
259 static void txstate(struct musb *musb, struct musb_request *req)
260 {
261 	u8			epnum = req->epnum;
262 	struct musb_ep		*musb_ep;
263 	void __iomem		*epio = musb->endpoints[epnum].regs;
264 	struct usb_request	*request;
265 	u16			fifo_count = 0, csr;
266 	int			use_dma = 0;
267 
268 	musb_ep = req->ep;
269 
270 	/* we shouldn't get here while DMA is active ... but we do ... */
271 	if (dma_channel_status(musb_ep->dma) == MUSB_DMA_STATUS_BUSY) {
272 		DBG(4, "dma pending...\n");
273 		return;
274 	}
275 
276 	/* read TXCSR before */
277 	csr = musb_readw(epio, MUSB_TXCSR);
278 
279 	request = &req->request;
280 	fifo_count = min(max_ep_writesize(musb, musb_ep),
281 			(int)(request->length - request->actual));
282 
283 	if (csr & MUSB_TXCSR_TXPKTRDY) {
284 		DBG(5, "%s old packet still ready , txcsr %03x\n",
285 				musb_ep->end_point.name, csr);
286 		return;
287 	}
288 
289 	if (csr & MUSB_TXCSR_P_SENDSTALL) {
290 		DBG(5, "%s stalling, txcsr %03x\n",
291 				musb_ep->end_point.name, csr);
292 		return;
293 	}
294 
295 	DBG(4, "hw_ep%d, maxpacket %d, fifo count %d, txcsr %03x\n",
296 			epnum, musb_ep->packet_sz, fifo_count,
297 			csr);
298 
299 #ifndef	CONFIG_MUSB_PIO_ONLY
300 	if (is_dma_capable() && musb_ep->dma) {
301 		struct dma_controller	*c = musb->dma_controller;
302 
303 		use_dma = (request->dma != DMA_ADDR_INVALID);
304 
305 		/* MUSB_TXCSR_P_ISO is still set correctly */
306 
307 #ifdef CONFIG_USB_INVENTRA_DMA
308 		{
309 			size_t request_size;
310 
311 			/* setup DMA, then program endpoint CSR */
312 			request_size = min_t(size_t, request->length,
313 						musb_ep->dma->max_len);
314 			if (request_size < musb_ep->packet_sz)
315 				musb_ep->dma->desired_mode = 0;
316 			else
317 				musb_ep->dma->desired_mode = 1;
318 
319 			use_dma = use_dma && c->channel_program(
320 					musb_ep->dma, musb_ep->packet_sz,
321 					musb_ep->dma->desired_mode,
322 					request->dma + request->actual, request_size);
323 			if (use_dma) {
324 				if (musb_ep->dma->desired_mode == 0) {
325 					/*
326 					 * We must not clear the DMAMODE bit
327 					 * before the DMAENAB bit -- and the
328 					 * latter doesn't always get cleared
329 					 * before we get here...
330 					 */
331 					csr &= ~(MUSB_TXCSR_AUTOSET
332 						| MUSB_TXCSR_DMAENAB);
333 					musb_writew(epio, MUSB_TXCSR, csr
334 						| MUSB_TXCSR_P_WZC_BITS);
335 					csr &= ~MUSB_TXCSR_DMAMODE;
336 					csr |= (MUSB_TXCSR_DMAENAB |
337 							MUSB_TXCSR_MODE);
338 					/* against programming guide */
339 				} else
340 					csr |= (MUSB_TXCSR_AUTOSET
341 							| MUSB_TXCSR_DMAENAB
342 							| MUSB_TXCSR_DMAMODE
343 							| MUSB_TXCSR_MODE);
344 
345 				csr &= ~MUSB_TXCSR_P_UNDERRUN;
346 				musb_writew(epio, MUSB_TXCSR, csr);
347 			}
348 		}
349 
350 #elif defined(CONFIG_USB_TI_CPPI_DMA)
351 		/* program endpoint CSR first, then setup DMA */
352 		csr &= ~(MUSB_TXCSR_P_UNDERRUN | MUSB_TXCSR_TXPKTRDY);
353 		csr |= MUSB_TXCSR_DMAENAB | MUSB_TXCSR_DMAMODE |
354 		       MUSB_TXCSR_MODE;
355 		musb_writew(epio, MUSB_TXCSR,
356 			(MUSB_TXCSR_P_WZC_BITS & ~MUSB_TXCSR_P_UNDERRUN)
357 				| csr);
358 
359 		/* ensure writebuffer is empty */
360 		csr = musb_readw(epio, MUSB_TXCSR);
361 
362 		/* NOTE host side sets DMAENAB later than this; both are
363 		 * OK since the transfer dma glue (between CPPI and Mentor
364 		 * fifos) just tells CPPI it could start.  Data only moves
365 		 * to the USB TX fifo when both fifos are ready.
366 		 */
367 
368 		/* "mode" is irrelevant here; handle terminating ZLPs like
369 		 * PIO does, since the hardware RNDIS mode seems unreliable
370 		 * except for the last-packet-is-already-short case.
371 		 */
372 		use_dma = use_dma && c->channel_program(
373 				musb_ep->dma, musb_ep->packet_sz,
374 				0,
375 				request->dma,
376 				request->length);
377 		if (!use_dma) {
378 			c->channel_release(musb_ep->dma);
379 			musb_ep->dma = NULL;
380 			csr &= ~MUSB_TXCSR_DMAENAB;
381 			musb_writew(epio, MUSB_TXCSR, csr);
382 			/* invariant: prequest->buf is non-null */
383 		}
384 #elif defined(CONFIG_USB_TUSB_OMAP_DMA)
385 		use_dma = use_dma && c->channel_program(
386 				musb_ep->dma, musb_ep->packet_sz,
387 				request->zero,
388 				request->dma,
389 				request->length);
390 #endif
391 	}
392 #endif
393 
394 	if (!use_dma) {
395 		musb_write_fifo(musb_ep->hw_ep, fifo_count,
396 				(u8 *) (request->buf + request->actual));
397 		request->actual += fifo_count;
398 		csr |= MUSB_TXCSR_TXPKTRDY;
399 		csr &= ~MUSB_TXCSR_P_UNDERRUN;
400 		musb_writew(epio, MUSB_TXCSR, csr);
401 	}
402 
403 	/* host may already have the data when this message shows... */
404 	DBG(3, "%s TX/IN %s len %d/%d, txcsr %04x, fifo %d/%d\n",
405 			musb_ep->end_point.name, use_dma ? "dma" : "pio",
406 			request->actual, request->length,
407 			musb_readw(epio, MUSB_TXCSR),
408 			fifo_count,
409 			musb_readw(epio, MUSB_TXMAXP));
410 }
411 
412 /*
413  * FIFO state update (e.g. data ready).
414  * Called from IRQ,  with controller locked.
415  */
416 void musb_g_tx(struct musb *musb, u8 epnum)
417 {
418 	u16			csr;
419 	struct usb_request	*request;
420 	u8 __iomem		*mbase = musb->mregs;
421 	struct musb_ep		*musb_ep = &musb->endpoints[epnum].ep_in;
422 	void __iomem		*epio = musb->endpoints[epnum].regs;
423 	struct dma_channel	*dma;
424 
425 	musb_ep_select(mbase, epnum);
426 	request = next_request(musb_ep);
427 
428 	csr = musb_readw(epio, MUSB_TXCSR);
429 	DBG(4, "<== %s, txcsr %04x\n", musb_ep->end_point.name, csr);
430 
431 	dma = is_dma_capable() ? musb_ep->dma : NULL;
432 
433 	/*
434 	 * REVISIT: for high bandwidth, MUSB_TXCSR_P_INCOMPTX
435 	 * probably rates reporting as a host error.
436 	 */
437 	if (csr & MUSB_TXCSR_P_SENTSTALL) {
438 		csr |=	MUSB_TXCSR_P_WZC_BITS;
439 		csr &= ~MUSB_TXCSR_P_SENTSTALL;
440 		musb_writew(epio, MUSB_TXCSR, csr);
441 		return;
442 	}
443 
444 	if (csr & MUSB_TXCSR_P_UNDERRUN) {
445 		/* We NAKed, no big deal... little reason to care. */
446 		csr |=	 MUSB_TXCSR_P_WZC_BITS;
447 		csr &= ~(MUSB_TXCSR_P_UNDERRUN | MUSB_TXCSR_TXPKTRDY);
448 		musb_writew(epio, MUSB_TXCSR, csr);
449 		DBG(20, "underrun on ep%d, req %p\n", epnum, request);
450 	}
451 
452 	if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
453 		/*
454 		 * SHOULD NOT HAPPEN... has with CPPI though, after
455 		 * changing SENDSTALL (and other cases); harmless?
456 		 */
457 		DBG(5, "%s dma still busy?\n", musb_ep->end_point.name);
458 		return;
459 	}
460 
461 	if (request) {
462 		u8	is_dma = 0;
463 
464 		if (dma && (csr & MUSB_TXCSR_DMAENAB)) {
465 			is_dma = 1;
466 			csr |= MUSB_TXCSR_P_WZC_BITS;
467 			csr &= ~(MUSB_TXCSR_DMAENAB | MUSB_TXCSR_P_UNDERRUN |
468 				 MUSB_TXCSR_TXPKTRDY);
469 			musb_writew(epio, MUSB_TXCSR, csr);
470 			/* Ensure writebuffer is empty. */
471 			csr = musb_readw(epio, MUSB_TXCSR);
472 			request->actual += musb_ep->dma->actual_len;
473 			DBG(4, "TXCSR%d %04x, DMA off, len %zu, req %p\n",
474 				epnum, csr, musb_ep->dma->actual_len, request);
475 		}
476 
477 		if (is_dma || request->actual == request->length) {
478 			/*
479 			 * First, maybe a terminating short packet. Some DMA
480 			 * engines might handle this by themselves.
481 			 */
482 			if ((request->zero && request->length
483 				&& request->length % musb_ep->packet_sz == 0)
484 #ifdef CONFIG_USB_INVENTRA_DMA
485 				|| (is_dma && (!dma->desired_mode ||
486 					(request->actual &
487 						(musb_ep->packet_sz - 1))))
488 #endif
489 			) {
490 				/*
491 				 * On DMA completion, FIFO may not be
492 				 * available yet...
493 				 */
494 				if (csr & MUSB_TXCSR_TXPKTRDY)
495 					return;
496 
497 				DBG(4, "sending zero pkt\n");
498 				musb_writew(epio, MUSB_TXCSR, MUSB_TXCSR_MODE
499 						| MUSB_TXCSR_TXPKTRDY);
500 				request->zero = 0;
501 			}
502 
503 			/* ... or if not, then complete it. */
504 			musb_g_giveback(musb_ep, request, 0);
505 
506 			/*
507 			 * Kickstart next transfer if appropriate;
508 			 * the packet that just completed might not
509 			 * be transmitted for hours or days.
510 			 * REVISIT for double buffering...
511 			 * FIXME revisit for stalls too...
512 			 */
513 			musb_ep_select(mbase, epnum);
514 			csr = musb_readw(epio, MUSB_TXCSR);
515 			if (csr & MUSB_TXCSR_FIFONOTEMPTY)
516 				return;
517 
518 			request = musb_ep->desc ? next_request(musb_ep) : NULL;
519 			if (!request) {
520 				DBG(4, "%s idle now\n",
521 					musb_ep->end_point.name);
522 				return;
523 			}
524 		}
525 
526 		txstate(musb, to_musb_request(request));
527 	}
528 }
529 
530 /* ------------------------------------------------------------ */
531 
532 #ifdef CONFIG_USB_INVENTRA_DMA
533 
534 /* Peripheral rx (OUT) using Mentor DMA works as follows:
535 	- Only mode 0 is used.
536 
537 	- Request is queued by the gadget class driver.
538 		-> if queue was previously empty, rxstate()
539 
540 	- Host sends OUT token which causes an endpoint interrupt
541 	  /\      -> RxReady
542 	  |	      -> if request queued, call rxstate
543 	  |		/\	-> setup DMA
544 	  |		|	     -> DMA interrupt on completion
545 	  |		|		-> RxReady
546 	  |		|		      -> stop DMA
547 	  |		|		      -> ack the read
548 	  |		|		      -> if data recd = max expected
549 	  |		|				by the request, or host
550 	  |		|				sent a short packet,
551 	  |		|				complete the request,
552 	  |		|				and start the next one.
553 	  |		|_____________________________________|
554 	  |					 else just wait for the host
555 	  |					    to send the next OUT token.
556 	  |__________________________________________________|
557 
558  * Non-Mentor DMA engines can of course work differently.
559  */
560 
561 #endif
562 
563 /*
564  * Context: controller locked, IRQs blocked, endpoint selected
565  */
566 static void rxstate(struct musb *musb, struct musb_request *req)
567 {
568 	const u8		epnum = req->epnum;
569 	struct usb_request	*request = &req->request;
570 	struct musb_ep		*musb_ep = &musb->endpoints[epnum].ep_out;
571 	void __iomem		*epio = musb->endpoints[epnum].regs;
572 	unsigned		fifo_count = 0;
573 	u16			len = musb_ep->packet_sz;
574 	u16			csr = musb_readw(epio, MUSB_RXCSR);
575 
576 	/* We shouldn't get here while DMA is active, but we do... */
577 	if (dma_channel_status(musb_ep->dma) == MUSB_DMA_STATUS_BUSY) {
578 		DBG(4, "DMA pending...\n");
579 		return;
580 	}
581 
582 	if (csr & MUSB_RXCSR_P_SENDSTALL) {
583 		DBG(5, "%s stalling, RXCSR %04x\n",
584 		    musb_ep->end_point.name, csr);
585 		return;
586 	}
587 
588 	if (is_cppi_enabled() && musb_ep->dma) {
589 		struct dma_controller	*c = musb->dma_controller;
590 		struct dma_channel	*channel = musb_ep->dma;
591 
592 		/* NOTE:  CPPI won't actually stop advancing the DMA
593 		 * queue after short packet transfers, so this is almost
594 		 * always going to run as IRQ-per-packet DMA so that
595 		 * faults will be handled correctly.
596 		 */
597 		if (c->channel_program(channel,
598 				musb_ep->packet_sz,
599 				!request->short_not_ok,
600 				request->dma + request->actual,
601 				request->length - request->actual)) {
602 
603 			/* make sure that if an rxpkt arrived after the irq,
604 			 * the cppi engine will be ready to take it as soon
605 			 * as DMA is enabled
606 			 */
607 			csr &= ~(MUSB_RXCSR_AUTOCLEAR
608 					| MUSB_RXCSR_DMAMODE);
609 			csr |= MUSB_RXCSR_DMAENAB | MUSB_RXCSR_P_WZC_BITS;
610 			musb_writew(epio, MUSB_RXCSR, csr);
611 			return;
612 		}
613 	}
614 
615 	if (csr & MUSB_RXCSR_RXPKTRDY) {
616 		len = musb_readw(epio, MUSB_RXCOUNT);
617 		if (request->actual < request->length) {
618 #ifdef CONFIG_USB_INVENTRA_DMA
619 			if (is_dma_capable() && musb_ep->dma) {
620 				struct dma_controller	*c;
621 				struct dma_channel	*channel;
622 				int			use_dma = 0;
623 
624 				c = musb->dma_controller;
625 				channel = musb_ep->dma;
626 
627 	/* We use DMA Req mode 0 in rx_csr, and DMA controller operates in
628 	 * mode 0 only. So we do not get endpoint interrupts due to DMA
629 	 * completion. We only get interrupts from DMA controller.
630 	 *
631 	 * We could operate in DMA mode 1 if we knew the size of the tranfer
632 	 * in advance. For mass storage class, request->length = what the host
633 	 * sends, so that'd work.  But for pretty much everything else,
634 	 * request->length is routinely more than what the host sends. For
635 	 * most these gadgets, end of is signified either by a short packet,
636 	 * or filling the last byte of the buffer.  (Sending extra data in
637 	 * that last pckate should trigger an overflow fault.)  But in mode 1,
638 	 * we don't get DMA completion interrrupt for short packets.
639 	 *
640 	 * Theoretically, we could enable DMAReq irq (MUSB_RXCSR_DMAMODE = 1),
641 	 * to get endpoint interrupt on every DMA req, but that didn't seem
642 	 * to work reliably.
643 	 *
644 	 * REVISIT an updated g_file_storage can set req->short_not_ok, which
645 	 * then becomes usable as a runtime "use mode 1" hint...
646 	 */
647 
648 				csr |= MUSB_RXCSR_DMAENAB;
649 #ifdef USE_MODE1
650 				csr |= MUSB_RXCSR_AUTOCLEAR;
651 				/* csr |= MUSB_RXCSR_DMAMODE; */
652 
653 				/* this special sequence (enabling and then
654 				 * disabling MUSB_RXCSR_DMAMODE) is required
655 				 * to get DMAReq to activate
656 				 */
657 				musb_writew(epio, MUSB_RXCSR,
658 					csr | MUSB_RXCSR_DMAMODE);
659 #endif
660 				musb_writew(epio, MUSB_RXCSR, csr);
661 
662 				if (request->actual < request->length) {
663 					int transfer_size = 0;
664 #ifdef USE_MODE1
665 					transfer_size = min(request->length,
666 							channel->max_len);
667 #else
668 					transfer_size = len;
669 #endif
670 					if (transfer_size <= musb_ep->packet_sz)
671 						musb_ep->dma->desired_mode = 0;
672 					else
673 						musb_ep->dma->desired_mode = 1;
674 
675 					use_dma = c->channel_program(
676 							channel,
677 							musb_ep->packet_sz,
678 							channel->desired_mode,
679 							request->dma
680 							+ request->actual,
681 							transfer_size);
682 				}
683 
684 				if (use_dma)
685 					return;
686 			}
687 #endif	/* Mentor's DMA */
688 
689 			fifo_count = request->length - request->actual;
690 			DBG(3, "%s OUT/RX pio fifo %d/%d, maxpacket %d\n",
691 					musb_ep->end_point.name,
692 					len, fifo_count,
693 					musb_ep->packet_sz);
694 
695 			fifo_count = min_t(unsigned, len, fifo_count);
696 
697 #ifdef	CONFIG_USB_TUSB_OMAP_DMA
698 			if (tusb_dma_omap() && musb_ep->dma) {
699 				struct dma_controller *c = musb->dma_controller;
700 				struct dma_channel *channel = musb_ep->dma;
701 				u32 dma_addr = request->dma + request->actual;
702 				int ret;
703 
704 				ret = c->channel_program(channel,
705 						musb_ep->packet_sz,
706 						channel->desired_mode,
707 						dma_addr,
708 						fifo_count);
709 				if (ret)
710 					return;
711 			}
712 #endif
713 
714 			musb_read_fifo(musb_ep->hw_ep, fifo_count, (u8 *)
715 					(request->buf + request->actual));
716 			request->actual += fifo_count;
717 
718 			/* REVISIT if we left anything in the fifo, flush
719 			 * it and report -EOVERFLOW
720 			 */
721 
722 			/* ack the read! */
723 			csr |= MUSB_RXCSR_P_WZC_BITS;
724 			csr &= ~MUSB_RXCSR_RXPKTRDY;
725 			musb_writew(epio, MUSB_RXCSR, csr);
726 		}
727 	}
728 
729 	/* reach the end or short packet detected */
730 	if (request->actual == request->length || len < musb_ep->packet_sz)
731 		musb_g_giveback(musb_ep, request, 0);
732 }
733 
734 /*
735  * Data ready for a request; called from IRQ
736  */
737 void musb_g_rx(struct musb *musb, u8 epnum)
738 {
739 	u16			csr;
740 	struct usb_request	*request;
741 	void __iomem		*mbase = musb->mregs;
742 	struct musb_ep		*musb_ep = &musb->endpoints[epnum].ep_out;
743 	void __iomem		*epio = musb->endpoints[epnum].regs;
744 	struct dma_channel	*dma;
745 
746 	musb_ep_select(mbase, epnum);
747 
748 	request = next_request(musb_ep);
749 	if (!request)
750 		return;
751 
752 	csr = musb_readw(epio, MUSB_RXCSR);
753 	dma = is_dma_capable() ? musb_ep->dma : NULL;
754 
755 	DBG(4, "<== %s, rxcsr %04x%s %p\n", musb_ep->end_point.name,
756 			csr, dma ? " (dma)" : "", request);
757 
758 	if (csr & MUSB_RXCSR_P_SENTSTALL) {
759 		csr |= MUSB_RXCSR_P_WZC_BITS;
760 		csr &= ~MUSB_RXCSR_P_SENTSTALL;
761 		musb_writew(epio, MUSB_RXCSR, csr);
762 		return;
763 	}
764 
765 	if (csr & MUSB_RXCSR_P_OVERRUN) {
766 		/* csr |= MUSB_RXCSR_P_WZC_BITS; */
767 		csr &= ~MUSB_RXCSR_P_OVERRUN;
768 		musb_writew(epio, MUSB_RXCSR, csr);
769 
770 		DBG(3, "%s iso overrun on %p\n", musb_ep->name, request);
771 		if (request && request->status == -EINPROGRESS)
772 			request->status = -EOVERFLOW;
773 	}
774 	if (csr & MUSB_RXCSR_INCOMPRX) {
775 		/* REVISIT not necessarily an error */
776 		DBG(4, "%s, incomprx\n", musb_ep->end_point.name);
777 	}
778 
779 	if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
780 		/* "should not happen"; likely RXPKTRDY pending for DMA */
781 		DBG((csr & MUSB_RXCSR_DMAENAB) ? 4 : 1,
782 			"%s busy, csr %04x\n",
783 			musb_ep->end_point.name, csr);
784 		return;
785 	}
786 
787 	if (dma && (csr & MUSB_RXCSR_DMAENAB)) {
788 		csr &= ~(MUSB_RXCSR_AUTOCLEAR
789 				| MUSB_RXCSR_DMAENAB
790 				| MUSB_RXCSR_DMAMODE);
791 		musb_writew(epio, MUSB_RXCSR,
792 			MUSB_RXCSR_P_WZC_BITS | csr);
793 
794 		request->actual += musb_ep->dma->actual_len;
795 
796 		DBG(4, "RXCSR%d %04x, dma off, %04x, len %zu, req %p\n",
797 			epnum, csr,
798 			musb_readw(epio, MUSB_RXCSR),
799 			musb_ep->dma->actual_len, request);
800 
801 #if defined(CONFIG_USB_INVENTRA_DMA) || defined(CONFIG_USB_TUSB_OMAP_DMA)
802 		/* Autoclear doesn't clear RxPktRdy for short packets */
803 		if ((dma->desired_mode == 0)
804 				|| (dma->actual_len
805 					& (musb_ep->packet_sz - 1))) {
806 			/* ack the read! */
807 			csr &= ~MUSB_RXCSR_RXPKTRDY;
808 			musb_writew(epio, MUSB_RXCSR, csr);
809 		}
810 
811 		/* incomplete, and not short? wait for next IN packet */
812 		if ((request->actual < request->length)
813 				&& (musb_ep->dma->actual_len
814 					== musb_ep->packet_sz))
815 			return;
816 #endif
817 		musb_g_giveback(musb_ep, request, 0);
818 
819 		request = next_request(musb_ep);
820 		if (!request)
821 			return;
822 	}
823 
824 	/* analyze request if the ep is hot */
825 	if (request)
826 		rxstate(musb, to_musb_request(request));
827 	else
828 		DBG(3, "packet waiting for %s%s request\n",
829 				musb_ep->desc ? "" : "inactive ",
830 				musb_ep->end_point.name);
831 	return;
832 }
833 
834 /* ------------------------------------------------------------ */
835 
836 static int musb_gadget_enable(struct usb_ep *ep,
837 			const struct usb_endpoint_descriptor *desc)
838 {
839 	unsigned long		flags;
840 	struct musb_ep		*musb_ep;
841 	struct musb_hw_ep	*hw_ep;
842 	void __iomem		*regs;
843 	struct musb		*musb;
844 	void __iomem	*mbase;
845 	u8		epnum;
846 	u16		csr;
847 	unsigned	tmp;
848 	int		status = -EINVAL;
849 
850 	if (!ep || !desc)
851 		return -EINVAL;
852 
853 	musb_ep = to_musb_ep(ep);
854 	hw_ep = musb_ep->hw_ep;
855 	regs = hw_ep->regs;
856 	musb = musb_ep->musb;
857 	mbase = musb->mregs;
858 	epnum = musb_ep->current_epnum;
859 
860 	spin_lock_irqsave(&musb->lock, flags);
861 
862 	if (musb_ep->desc) {
863 		status = -EBUSY;
864 		goto fail;
865 	}
866 	musb_ep->type = usb_endpoint_type(desc);
867 
868 	/* check direction and (later) maxpacket size against endpoint */
869 	if (usb_endpoint_num(desc) != epnum)
870 		goto fail;
871 
872 	/* REVISIT this rules out high bandwidth periodic transfers */
873 	tmp = le16_to_cpu(desc->wMaxPacketSize);
874 	if (tmp & ~0x07ff)
875 		goto fail;
876 	musb_ep->packet_sz = tmp;
877 
878 	/* enable the interrupts for the endpoint, set the endpoint
879 	 * packet size (or fail), set the mode, clear the fifo
880 	 */
881 	musb_ep_select(mbase, epnum);
882 	if (usb_endpoint_dir_in(desc)) {
883 		u16 int_txe = musb_readw(mbase, MUSB_INTRTXE);
884 
885 		if (hw_ep->is_shared_fifo)
886 			musb_ep->is_in = 1;
887 		if (!musb_ep->is_in)
888 			goto fail;
889 		if (tmp > hw_ep->max_packet_sz_tx)
890 			goto fail;
891 
892 		int_txe |= (1 << epnum);
893 		musb_writew(mbase, MUSB_INTRTXE, int_txe);
894 
895 		/* REVISIT if can_bulk_split(), use by updating "tmp";
896 		 * likewise high bandwidth periodic tx
897 		 */
898 		musb_writew(regs, MUSB_TXMAXP, tmp);
899 
900 		csr = MUSB_TXCSR_MODE | MUSB_TXCSR_CLRDATATOG;
901 		if (musb_readw(regs, MUSB_TXCSR)
902 				& MUSB_TXCSR_FIFONOTEMPTY)
903 			csr |= MUSB_TXCSR_FLUSHFIFO;
904 		if (musb_ep->type == USB_ENDPOINT_XFER_ISOC)
905 			csr |= MUSB_TXCSR_P_ISO;
906 
907 		/* set twice in case of double buffering */
908 		musb_writew(regs, MUSB_TXCSR, csr);
909 		/* REVISIT may be inappropriate w/o FIFONOTEMPTY ... */
910 		musb_writew(regs, MUSB_TXCSR, csr);
911 
912 	} else {
913 		u16 int_rxe = musb_readw(mbase, MUSB_INTRRXE);
914 
915 		if (hw_ep->is_shared_fifo)
916 			musb_ep->is_in = 0;
917 		if (musb_ep->is_in)
918 			goto fail;
919 		if (tmp > hw_ep->max_packet_sz_rx)
920 			goto fail;
921 
922 		int_rxe |= (1 << epnum);
923 		musb_writew(mbase, MUSB_INTRRXE, int_rxe);
924 
925 		/* REVISIT if can_bulk_combine() use by updating "tmp"
926 		 * likewise high bandwidth periodic rx
927 		 */
928 		musb_writew(regs, MUSB_RXMAXP, tmp);
929 
930 		/* force shared fifo to OUT-only mode */
931 		if (hw_ep->is_shared_fifo) {
932 			csr = musb_readw(regs, MUSB_TXCSR);
933 			csr &= ~(MUSB_TXCSR_MODE | MUSB_TXCSR_TXPKTRDY);
934 			musb_writew(regs, MUSB_TXCSR, csr);
935 		}
936 
937 		csr = MUSB_RXCSR_FLUSHFIFO | MUSB_RXCSR_CLRDATATOG;
938 		if (musb_ep->type == USB_ENDPOINT_XFER_ISOC)
939 			csr |= MUSB_RXCSR_P_ISO;
940 		else if (musb_ep->type == USB_ENDPOINT_XFER_INT)
941 			csr |= MUSB_RXCSR_DISNYET;
942 
943 		/* set twice in case of double buffering */
944 		musb_writew(regs, MUSB_RXCSR, csr);
945 		musb_writew(regs, MUSB_RXCSR, csr);
946 	}
947 
948 	/* NOTE:  all the I/O code _should_ work fine without DMA, in case
949 	 * for some reason you run out of channels here.
950 	 */
951 	if (is_dma_capable() && musb->dma_controller) {
952 		struct dma_controller	*c = musb->dma_controller;
953 
954 		musb_ep->dma = c->channel_alloc(c, hw_ep,
955 				(desc->bEndpointAddress & USB_DIR_IN));
956 	} else
957 		musb_ep->dma = NULL;
958 
959 	musb_ep->desc = desc;
960 	musb_ep->busy = 0;
961 	musb_ep->wedged = 0;
962 	status = 0;
963 
964 	pr_debug("%s periph: enabled %s for %s %s, %smaxpacket %d\n",
965 			musb_driver_name, musb_ep->end_point.name,
966 			({ char *s; switch (musb_ep->type) {
967 			case USB_ENDPOINT_XFER_BULK:	s = "bulk"; break;
968 			case USB_ENDPOINT_XFER_INT:	s = "int"; break;
969 			default:			s = "iso"; break;
970 			}; s; }),
971 			musb_ep->is_in ? "IN" : "OUT",
972 			musb_ep->dma ? "dma, " : "",
973 			musb_ep->packet_sz);
974 
975 	schedule_work(&musb->irq_work);
976 
977 fail:
978 	spin_unlock_irqrestore(&musb->lock, flags);
979 	return status;
980 }
981 
982 /*
983  * Disable an endpoint flushing all requests queued.
984  */
985 static int musb_gadget_disable(struct usb_ep *ep)
986 {
987 	unsigned long	flags;
988 	struct musb	*musb;
989 	u8		epnum;
990 	struct musb_ep	*musb_ep;
991 	void __iomem	*epio;
992 	int		status = 0;
993 
994 	musb_ep = to_musb_ep(ep);
995 	musb = musb_ep->musb;
996 	epnum = musb_ep->current_epnum;
997 	epio = musb->endpoints[epnum].regs;
998 
999 	spin_lock_irqsave(&musb->lock, flags);
1000 	musb_ep_select(musb->mregs, epnum);
1001 
1002 	/* zero the endpoint sizes */
1003 	if (musb_ep->is_in) {
1004 		u16 int_txe = musb_readw(musb->mregs, MUSB_INTRTXE);
1005 		int_txe &= ~(1 << epnum);
1006 		musb_writew(musb->mregs, MUSB_INTRTXE, int_txe);
1007 		musb_writew(epio, MUSB_TXMAXP, 0);
1008 	} else {
1009 		u16 int_rxe = musb_readw(musb->mregs, MUSB_INTRRXE);
1010 		int_rxe &= ~(1 << epnum);
1011 		musb_writew(musb->mregs, MUSB_INTRRXE, int_rxe);
1012 		musb_writew(epio, MUSB_RXMAXP, 0);
1013 	}
1014 
1015 	musb_ep->desc = NULL;
1016 
1017 	/* abort all pending DMA and requests */
1018 	nuke(musb_ep, -ESHUTDOWN);
1019 
1020 	schedule_work(&musb->irq_work);
1021 
1022 	spin_unlock_irqrestore(&(musb->lock), flags);
1023 
1024 	DBG(2, "%s\n", musb_ep->end_point.name);
1025 
1026 	return status;
1027 }
1028 
1029 /*
1030  * Allocate a request for an endpoint.
1031  * Reused by ep0 code.
1032  */
1033 struct usb_request *musb_alloc_request(struct usb_ep *ep, gfp_t gfp_flags)
1034 {
1035 	struct musb_ep		*musb_ep = to_musb_ep(ep);
1036 	struct musb_request	*request = NULL;
1037 
1038 	request = kzalloc(sizeof *request, gfp_flags);
1039 	if (request) {
1040 		INIT_LIST_HEAD(&request->request.list);
1041 		request->request.dma = DMA_ADDR_INVALID;
1042 		request->epnum = musb_ep->current_epnum;
1043 		request->ep = musb_ep;
1044 	}
1045 
1046 	return &request->request;
1047 }
1048 
1049 /*
1050  * Free a request
1051  * Reused by ep0 code.
1052  */
1053 void musb_free_request(struct usb_ep *ep, struct usb_request *req)
1054 {
1055 	kfree(to_musb_request(req));
1056 }
1057 
1058 static LIST_HEAD(buffers);
1059 
1060 struct free_record {
1061 	struct list_head	list;
1062 	struct device		*dev;
1063 	unsigned		bytes;
1064 	dma_addr_t		dma;
1065 };
1066 
1067 /*
1068  * Context: controller locked, IRQs blocked.
1069  */
1070 static void musb_ep_restart(struct musb *musb, struct musb_request *req)
1071 {
1072 	DBG(3, "<== %s request %p len %u on hw_ep%d\n",
1073 		req->tx ? "TX/IN" : "RX/OUT",
1074 		&req->request, req->request.length, req->epnum);
1075 
1076 	musb_ep_select(musb->mregs, req->epnum);
1077 	if (req->tx)
1078 		txstate(musb, req);
1079 	else
1080 		rxstate(musb, req);
1081 }
1082 
1083 static int musb_gadget_queue(struct usb_ep *ep, struct usb_request *req,
1084 			gfp_t gfp_flags)
1085 {
1086 	struct musb_ep		*musb_ep;
1087 	struct musb_request	*request;
1088 	struct musb		*musb;
1089 	int			status = 0;
1090 	unsigned long		lockflags;
1091 
1092 	if (!ep || !req)
1093 		return -EINVAL;
1094 	if (!req->buf)
1095 		return -ENODATA;
1096 
1097 	musb_ep = to_musb_ep(ep);
1098 	musb = musb_ep->musb;
1099 
1100 	request = to_musb_request(req);
1101 	request->musb = musb;
1102 
1103 	if (request->ep != musb_ep)
1104 		return -EINVAL;
1105 
1106 	DBG(4, "<== to %s request=%p\n", ep->name, req);
1107 
1108 	/* request is mine now... */
1109 	request->request.actual = 0;
1110 	request->request.status = -EINPROGRESS;
1111 	request->epnum = musb_ep->current_epnum;
1112 	request->tx = musb_ep->is_in;
1113 
1114 	if (is_dma_capable() && musb_ep->dma) {
1115 		if (request->request.dma == DMA_ADDR_INVALID) {
1116 			request->request.dma = dma_map_single(
1117 					musb->controller,
1118 					request->request.buf,
1119 					request->request.length,
1120 					request->tx
1121 						? DMA_TO_DEVICE
1122 						: DMA_FROM_DEVICE);
1123 			request->mapped = 1;
1124 		} else {
1125 			dma_sync_single_for_device(musb->controller,
1126 					request->request.dma,
1127 					request->request.length,
1128 					request->tx
1129 						? DMA_TO_DEVICE
1130 						: DMA_FROM_DEVICE);
1131 			request->mapped = 0;
1132 		}
1133 	} else if (!req->buf) {
1134 		return -ENODATA;
1135 	} else
1136 		request->mapped = 0;
1137 
1138 	spin_lock_irqsave(&musb->lock, lockflags);
1139 
1140 	/* don't queue if the ep is down */
1141 	if (!musb_ep->desc) {
1142 		DBG(4, "req %p queued to %s while ep %s\n",
1143 				req, ep->name, "disabled");
1144 		status = -ESHUTDOWN;
1145 		goto cleanup;
1146 	}
1147 
1148 	/* add request to the list */
1149 	list_add_tail(&(request->request.list), &(musb_ep->req_list));
1150 
1151 	/* it this is the head of the queue, start i/o ... */
1152 	if (!musb_ep->busy && &request->request.list == musb_ep->req_list.next)
1153 		musb_ep_restart(musb, request);
1154 
1155 cleanup:
1156 	spin_unlock_irqrestore(&musb->lock, lockflags);
1157 	return status;
1158 }
1159 
1160 static int musb_gadget_dequeue(struct usb_ep *ep, struct usb_request *request)
1161 {
1162 	struct musb_ep		*musb_ep = to_musb_ep(ep);
1163 	struct usb_request	*r;
1164 	unsigned long		flags;
1165 	int			status = 0;
1166 	struct musb		*musb = musb_ep->musb;
1167 
1168 	if (!ep || !request || to_musb_request(request)->ep != musb_ep)
1169 		return -EINVAL;
1170 
1171 	spin_lock_irqsave(&musb->lock, flags);
1172 
1173 	list_for_each_entry(r, &musb_ep->req_list, list) {
1174 		if (r == request)
1175 			break;
1176 	}
1177 	if (r != request) {
1178 		DBG(3, "request %p not queued to %s\n", request, ep->name);
1179 		status = -EINVAL;
1180 		goto done;
1181 	}
1182 
1183 	/* if the hardware doesn't have the request, easy ... */
1184 	if (musb_ep->req_list.next != &request->list || musb_ep->busy)
1185 		musb_g_giveback(musb_ep, request, -ECONNRESET);
1186 
1187 	/* ... else abort the dma transfer ... */
1188 	else if (is_dma_capable() && musb_ep->dma) {
1189 		struct dma_controller	*c = musb->dma_controller;
1190 
1191 		musb_ep_select(musb->mregs, musb_ep->current_epnum);
1192 		if (c->channel_abort)
1193 			status = c->channel_abort(musb_ep->dma);
1194 		else
1195 			status = -EBUSY;
1196 		if (status == 0)
1197 			musb_g_giveback(musb_ep, request, -ECONNRESET);
1198 	} else {
1199 		/* NOTE: by sticking to easily tested hardware/driver states,
1200 		 * we leave counting of in-flight packets imprecise.
1201 		 */
1202 		musb_g_giveback(musb_ep, request, -ECONNRESET);
1203 	}
1204 
1205 done:
1206 	spin_unlock_irqrestore(&musb->lock, flags);
1207 	return status;
1208 }
1209 
1210 /*
1211  * Set or clear the halt bit of an endpoint. A halted enpoint won't tx/rx any
1212  * data but will queue requests.
1213  *
1214  * exported to ep0 code
1215  */
1216 static int musb_gadget_set_halt(struct usb_ep *ep, int value)
1217 {
1218 	struct musb_ep		*musb_ep = to_musb_ep(ep);
1219 	u8			epnum = musb_ep->current_epnum;
1220 	struct musb		*musb = musb_ep->musb;
1221 	void __iomem		*epio = musb->endpoints[epnum].regs;
1222 	void __iomem		*mbase;
1223 	unsigned long		flags;
1224 	u16			csr;
1225 	struct musb_request	*request;
1226 	int			status = 0;
1227 
1228 	if (!ep)
1229 		return -EINVAL;
1230 	mbase = musb->mregs;
1231 
1232 	spin_lock_irqsave(&musb->lock, flags);
1233 
1234 	if ((USB_ENDPOINT_XFER_ISOC == musb_ep->type)) {
1235 		status = -EINVAL;
1236 		goto done;
1237 	}
1238 
1239 	musb_ep_select(mbase, epnum);
1240 
1241 	request = to_musb_request(next_request(musb_ep));
1242 	if (value) {
1243 		if (request) {
1244 			DBG(3, "request in progress, cannot halt %s\n",
1245 			    ep->name);
1246 			status = -EAGAIN;
1247 			goto done;
1248 		}
1249 		/* Cannot portably stall with non-empty FIFO */
1250 		if (musb_ep->is_in) {
1251 			csr = musb_readw(epio, MUSB_TXCSR);
1252 			if (csr & MUSB_TXCSR_FIFONOTEMPTY) {
1253 				DBG(3, "FIFO busy, cannot halt %s\n", ep->name);
1254 				status = -EAGAIN;
1255 				goto done;
1256 			}
1257 		}
1258 	} else
1259 		musb_ep->wedged = 0;
1260 
1261 	/* set/clear the stall and toggle bits */
1262 	DBG(2, "%s: %s stall\n", ep->name, value ? "set" : "clear");
1263 	if (musb_ep->is_in) {
1264 		csr = musb_readw(epio, MUSB_TXCSR);
1265 		csr |= MUSB_TXCSR_P_WZC_BITS
1266 			| MUSB_TXCSR_CLRDATATOG;
1267 		if (value)
1268 			csr |= MUSB_TXCSR_P_SENDSTALL;
1269 		else
1270 			csr &= ~(MUSB_TXCSR_P_SENDSTALL
1271 				| MUSB_TXCSR_P_SENTSTALL);
1272 		csr &= ~MUSB_TXCSR_TXPKTRDY;
1273 		musb_writew(epio, MUSB_TXCSR, csr);
1274 	} else {
1275 		csr = musb_readw(epio, MUSB_RXCSR);
1276 		csr |= MUSB_RXCSR_P_WZC_BITS
1277 			| MUSB_RXCSR_FLUSHFIFO
1278 			| MUSB_RXCSR_CLRDATATOG;
1279 		if (value)
1280 			csr |= MUSB_RXCSR_P_SENDSTALL;
1281 		else
1282 			csr &= ~(MUSB_RXCSR_P_SENDSTALL
1283 				| MUSB_RXCSR_P_SENTSTALL);
1284 		musb_writew(epio, MUSB_RXCSR, csr);
1285 	}
1286 
1287 	/* maybe start the first request in the queue */
1288 	if (!musb_ep->busy && !value && request) {
1289 		DBG(3, "restarting the request\n");
1290 		musb_ep_restart(musb, request);
1291 	}
1292 
1293 done:
1294 	spin_unlock_irqrestore(&musb->lock, flags);
1295 	return status;
1296 }
1297 
1298 /*
1299  * Sets the halt feature with the clear requests ignored
1300  */
1301 static int musb_gadget_set_wedge(struct usb_ep *ep)
1302 {
1303 	struct musb_ep		*musb_ep = to_musb_ep(ep);
1304 
1305 	if (!ep)
1306 		return -EINVAL;
1307 
1308 	musb_ep->wedged = 1;
1309 
1310 	return usb_ep_set_halt(ep);
1311 }
1312 
1313 static int musb_gadget_fifo_status(struct usb_ep *ep)
1314 {
1315 	struct musb_ep		*musb_ep = to_musb_ep(ep);
1316 	void __iomem		*epio = musb_ep->hw_ep->regs;
1317 	int			retval = -EINVAL;
1318 
1319 	if (musb_ep->desc && !musb_ep->is_in) {
1320 		struct musb		*musb = musb_ep->musb;
1321 		int			epnum = musb_ep->current_epnum;
1322 		void __iomem		*mbase = musb->mregs;
1323 		unsigned long		flags;
1324 
1325 		spin_lock_irqsave(&musb->lock, flags);
1326 
1327 		musb_ep_select(mbase, epnum);
1328 		/* FIXME return zero unless RXPKTRDY is set */
1329 		retval = musb_readw(epio, MUSB_RXCOUNT);
1330 
1331 		spin_unlock_irqrestore(&musb->lock, flags);
1332 	}
1333 	return retval;
1334 }
1335 
1336 static void musb_gadget_fifo_flush(struct usb_ep *ep)
1337 {
1338 	struct musb_ep	*musb_ep = to_musb_ep(ep);
1339 	struct musb	*musb = musb_ep->musb;
1340 	u8		epnum = musb_ep->current_epnum;
1341 	void __iomem	*epio = musb->endpoints[epnum].regs;
1342 	void __iomem	*mbase;
1343 	unsigned long	flags;
1344 	u16		csr, int_txe;
1345 
1346 	mbase = musb->mregs;
1347 
1348 	spin_lock_irqsave(&musb->lock, flags);
1349 	musb_ep_select(mbase, (u8) epnum);
1350 
1351 	/* disable interrupts */
1352 	int_txe = musb_readw(mbase, MUSB_INTRTXE);
1353 	musb_writew(mbase, MUSB_INTRTXE, int_txe & ~(1 << epnum));
1354 
1355 	if (musb_ep->is_in) {
1356 		csr = musb_readw(epio, MUSB_TXCSR);
1357 		if (csr & MUSB_TXCSR_FIFONOTEMPTY) {
1358 			csr |= MUSB_TXCSR_FLUSHFIFO | MUSB_TXCSR_P_WZC_BITS;
1359 			musb_writew(epio, MUSB_TXCSR, csr);
1360 			/* REVISIT may be inappropriate w/o FIFONOTEMPTY ... */
1361 			musb_writew(epio, MUSB_TXCSR, csr);
1362 		}
1363 	} else {
1364 		csr = musb_readw(epio, MUSB_RXCSR);
1365 		csr |= MUSB_RXCSR_FLUSHFIFO | MUSB_RXCSR_P_WZC_BITS;
1366 		musb_writew(epio, MUSB_RXCSR, csr);
1367 		musb_writew(epio, MUSB_RXCSR, csr);
1368 	}
1369 
1370 	/* re-enable interrupt */
1371 	musb_writew(mbase, MUSB_INTRTXE, int_txe);
1372 	spin_unlock_irqrestore(&musb->lock, flags);
1373 }
1374 
1375 static const struct usb_ep_ops musb_ep_ops = {
1376 	.enable		= musb_gadget_enable,
1377 	.disable	= musb_gadget_disable,
1378 	.alloc_request	= musb_alloc_request,
1379 	.free_request	= musb_free_request,
1380 	.queue		= musb_gadget_queue,
1381 	.dequeue	= musb_gadget_dequeue,
1382 	.set_halt	= musb_gadget_set_halt,
1383 	.set_wedge	= musb_gadget_set_wedge,
1384 	.fifo_status	= musb_gadget_fifo_status,
1385 	.fifo_flush	= musb_gadget_fifo_flush
1386 };
1387 
1388 /* ----------------------------------------------------------------------- */
1389 
1390 static int musb_gadget_get_frame(struct usb_gadget *gadget)
1391 {
1392 	struct musb	*musb = gadget_to_musb(gadget);
1393 
1394 	return (int)musb_readw(musb->mregs, MUSB_FRAME);
1395 }
1396 
1397 static int musb_gadget_wakeup(struct usb_gadget *gadget)
1398 {
1399 	struct musb	*musb = gadget_to_musb(gadget);
1400 	void __iomem	*mregs = musb->mregs;
1401 	unsigned long	flags;
1402 	int		status = -EINVAL;
1403 	u8		power, devctl;
1404 	int		retries;
1405 
1406 	spin_lock_irqsave(&musb->lock, flags);
1407 
1408 	switch (musb->xceiv->state) {
1409 	case OTG_STATE_B_PERIPHERAL:
1410 		/* NOTE:  OTG state machine doesn't include B_SUSPENDED;
1411 		 * that's part of the standard usb 1.1 state machine, and
1412 		 * doesn't affect OTG transitions.
1413 		 */
1414 		if (musb->may_wakeup && musb->is_suspended)
1415 			break;
1416 		goto done;
1417 	case OTG_STATE_B_IDLE:
1418 		/* Start SRP ... OTG not required. */
1419 		devctl = musb_readb(mregs, MUSB_DEVCTL);
1420 		DBG(2, "Sending SRP: devctl: %02x\n", devctl);
1421 		devctl |= MUSB_DEVCTL_SESSION;
1422 		musb_writeb(mregs, MUSB_DEVCTL, devctl);
1423 		devctl = musb_readb(mregs, MUSB_DEVCTL);
1424 		retries = 100;
1425 		while (!(devctl & MUSB_DEVCTL_SESSION)) {
1426 			devctl = musb_readb(mregs, MUSB_DEVCTL);
1427 			if (retries-- < 1)
1428 				break;
1429 		}
1430 		retries = 10000;
1431 		while (devctl & MUSB_DEVCTL_SESSION) {
1432 			devctl = musb_readb(mregs, MUSB_DEVCTL);
1433 			if (retries-- < 1)
1434 				break;
1435 		}
1436 
1437 		/* Block idling for at least 1s */
1438 		musb_platform_try_idle(musb,
1439 			jiffies + msecs_to_jiffies(1 * HZ));
1440 
1441 		status = 0;
1442 		goto done;
1443 	default:
1444 		DBG(2, "Unhandled wake: %s\n", otg_state_string(musb));
1445 		goto done;
1446 	}
1447 
1448 	status = 0;
1449 
1450 	power = musb_readb(mregs, MUSB_POWER);
1451 	power |= MUSB_POWER_RESUME;
1452 	musb_writeb(mregs, MUSB_POWER, power);
1453 	DBG(2, "issue wakeup\n");
1454 
1455 	/* FIXME do this next chunk in a timer callback, no udelay */
1456 	mdelay(2);
1457 
1458 	power = musb_readb(mregs, MUSB_POWER);
1459 	power &= ~MUSB_POWER_RESUME;
1460 	musb_writeb(mregs, MUSB_POWER, power);
1461 done:
1462 	spin_unlock_irqrestore(&musb->lock, flags);
1463 	return status;
1464 }
1465 
1466 static int
1467 musb_gadget_set_self_powered(struct usb_gadget *gadget, int is_selfpowered)
1468 {
1469 	struct musb	*musb = gadget_to_musb(gadget);
1470 
1471 	musb->is_self_powered = !!is_selfpowered;
1472 	return 0;
1473 }
1474 
1475 static void musb_pullup(struct musb *musb, int is_on)
1476 {
1477 	u8 power;
1478 
1479 	power = musb_readb(musb->mregs, MUSB_POWER);
1480 	if (is_on)
1481 		power |= MUSB_POWER_SOFTCONN;
1482 	else
1483 		power &= ~MUSB_POWER_SOFTCONN;
1484 
1485 	/* FIXME if on, HdrcStart; if off, HdrcStop */
1486 
1487 	DBG(3, "gadget %s D+ pullup %s\n",
1488 		musb->gadget_driver->function, is_on ? "on" : "off");
1489 	musb_writeb(musb->mregs, MUSB_POWER, power);
1490 }
1491 
1492 #if 0
1493 static int musb_gadget_vbus_session(struct usb_gadget *gadget, int is_active)
1494 {
1495 	DBG(2, "<= %s =>\n", __func__);
1496 
1497 	/*
1498 	 * FIXME iff driver's softconnect flag is set (as it is during probe,
1499 	 * though that can clear it), just musb_pullup().
1500 	 */
1501 
1502 	return -EINVAL;
1503 }
1504 #endif
1505 
1506 static int musb_gadget_vbus_draw(struct usb_gadget *gadget, unsigned mA)
1507 {
1508 	struct musb	*musb = gadget_to_musb(gadget);
1509 
1510 	if (!musb->xceiv->set_power)
1511 		return -EOPNOTSUPP;
1512 	return otg_set_power(musb->xceiv, mA);
1513 }
1514 
1515 static int musb_gadget_pullup(struct usb_gadget *gadget, int is_on)
1516 {
1517 	struct musb	*musb = gadget_to_musb(gadget);
1518 	unsigned long	flags;
1519 
1520 	is_on = !!is_on;
1521 
1522 	/* NOTE: this assumes we are sensing vbus; we'd rather
1523 	 * not pullup unless the B-session is active.
1524 	 */
1525 	spin_lock_irqsave(&musb->lock, flags);
1526 	if (is_on != musb->softconnect) {
1527 		musb->softconnect = is_on;
1528 		musb_pullup(musb, is_on);
1529 	}
1530 	spin_unlock_irqrestore(&musb->lock, flags);
1531 	return 0;
1532 }
1533 
1534 static const struct usb_gadget_ops musb_gadget_operations = {
1535 	.get_frame		= musb_gadget_get_frame,
1536 	.wakeup			= musb_gadget_wakeup,
1537 	.set_selfpowered	= musb_gadget_set_self_powered,
1538 	/* .vbus_session		= musb_gadget_vbus_session, */
1539 	.vbus_draw		= musb_gadget_vbus_draw,
1540 	.pullup			= musb_gadget_pullup,
1541 };
1542 
1543 /* ----------------------------------------------------------------------- */
1544 
1545 /* Registration */
1546 
1547 /* Only this registration code "knows" the rule (from USB standards)
1548  * about there being only one external upstream port.  It assumes
1549  * all peripheral ports are external...
1550  */
1551 static struct musb *the_gadget;
1552 
1553 static void musb_gadget_release(struct device *dev)
1554 {
1555 	/* kref_put(WHAT) */
1556 	dev_dbg(dev, "%s\n", __func__);
1557 }
1558 
1559 
1560 static void __init
1561 init_peripheral_ep(struct musb *musb, struct musb_ep *ep, u8 epnum, int is_in)
1562 {
1563 	struct musb_hw_ep	*hw_ep = musb->endpoints + epnum;
1564 
1565 	memset(ep, 0, sizeof *ep);
1566 
1567 	ep->current_epnum = epnum;
1568 	ep->musb = musb;
1569 	ep->hw_ep = hw_ep;
1570 	ep->is_in = is_in;
1571 
1572 	INIT_LIST_HEAD(&ep->req_list);
1573 
1574 	sprintf(ep->name, "ep%d%s", epnum,
1575 			(!epnum || hw_ep->is_shared_fifo) ? "" : (
1576 				is_in ? "in" : "out"));
1577 	ep->end_point.name = ep->name;
1578 	INIT_LIST_HEAD(&ep->end_point.ep_list);
1579 	if (!epnum) {
1580 		ep->end_point.maxpacket = 64;
1581 		ep->end_point.ops = &musb_g_ep0_ops;
1582 		musb->g.ep0 = &ep->end_point;
1583 	} else {
1584 		if (is_in)
1585 			ep->end_point.maxpacket = hw_ep->max_packet_sz_tx;
1586 		else
1587 			ep->end_point.maxpacket = hw_ep->max_packet_sz_rx;
1588 		ep->end_point.ops = &musb_ep_ops;
1589 		list_add_tail(&ep->end_point.ep_list, &musb->g.ep_list);
1590 	}
1591 }
1592 
1593 /*
1594  * Initialize the endpoints exposed to peripheral drivers, with backlinks
1595  * to the rest of the driver state.
1596  */
1597 static inline void __init musb_g_init_endpoints(struct musb *musb)
1598 {
1599 	u8			epnum;
1600 	struct musb_hw_ep	*hw_ep;
1601 	unsigned		count = 0;
1602 
1603 	/* intialize endpoint list just once */
1604 	INIT_LIST_HEAD(&(musb->g.ep_list));
1605 
1606 	for (epnum = 0, hw_ep = musb->endpoints;
1607 			epnum < musb->nr_endpoints;
1608 			epnum++, hw_ep++) {
1609 		if (hw_ep->is_shared_fifo /* || !epnum */) {
1610 			init_peripheral_ep(musb, &hw_ep->ep_in, epnum, 0);
1611 			count++;
1612 		} else {
1613 			if (hw_ep->max_packet_sz_tx) {
1614 				init_peripheral_ep(musb, &hw_ep->ep_in,
1615 							epnum, 1);
1616 				count++;
1617 			}
1618 			if (hw_ep->max_packet_sz_rx) {
1619 				init_peripheral_ep(musb, &hw_ep->ep_out,
1620 							epnum, 0);
1621 				count++;
1622 			}
1623 		}
1624 	}
1625 }
1626 
1627 /* called once during driver setup to initialize and link into
1628  * the driver model; memory is zeroed.
1629  */
1630 int __init musb_gadget_setup(struct musb *musb)
1631 {
1632 	int status;
1633 
1634 	/* REVISIT minor race:  if (erroneously) setting up two
1635 	 * musb peripherals at the same time, only the bus lock
1636 	 * is probably held.
1637 	 */
1638 	if (the_gadget)
1639 		return -EBUSY;
1640 	the_gadget = musb;
1641 
1642 	musb->g.ops = &musb_gadget_operations;
1643 	musb->g.is_dualspeed = 1;
1644 	musb->g.speed = USB_SPEED_UNKNOWN;
1645 
1646 	/* this "gadget" abstracts/virtualizes the controller */
1647 	dev_set_name(&musb->g.dev, "gadget");
1648 	musb->g.dev.parent = musb->controller;
1649 	musb->g.dev.dma_mask = musb->controller->dma_mask;
1650 	musb->g.dev.release = musb_gadget_release;
1651 	musb->g.name = musb_driver_name;
1652 
1653 	if (is_otg_enabled(musb))
1654 		musb->g.is_otg = 1;
1655 
1656 	musb_g_init_endpoints(musb);
1657 
1658 	musb->is_active = 0;
1659 	musb_platform_try_idle(musb, 0);
1660 
1661 	status = device_register(&musb->g.dev);
1662 	if (status != 0)
1663 		the_gadget = NULL;
1664 	return status;
1665 }
1666 
1667 void musb_gadget_cleanup(struct musb *musb)
1668 {
1669 	if (musb != the_gadget)
1670 		return;
1671 
1672 	device_unregister(&musb->g.dev);
1673 	the_gadget = NULL;
1674 }
1675 
1676 /*
1677  * Register the gadget driver. Used by gadget drivers when
1678  * registering themselves with the controller.
1679  *
1680  * -EINVAL something went wrong (not driver)
1681  * -EBUSY another gadget is already using the controller
1682  * -ENOMEM no memeory to perform the operation
1683  *
1684  * @param driver the gadget driver
1685  * @return <0 if error, 0 if everything is fine
1686  */
1687 int usb_gadget_register_driver(struct usb_gadget_driver *driver)
1688 {
1689 	int retval;
1690 	unsigned long flags;
1691 	struct musb *musb = the_gadget;
1692 
1693 	if (!driver
1694 			|| driver->speed != USB_SPEED_HIGH
1695 			|| !driver->bind
1696 			|| !driver->setup)
1697 		return -EINVAL;
1698 
1699 	/* driver must be initialized to support peripheral mode */
1700 	if (!musb || !(musb->board_mode == MUSB_OTG
1701 				|| musb->board_mode != MUSB_OTG)) {
1702 		DBG(1, "%s, no dev??\n", __func__);
1703 		return -ENODEV;
1704 	}
1705 
1706 	DBG(3, "registering driver %s\n", driver->function);
1707 	spin_lock_irqsave(&musb->lock, flags);
1708 
1709 	if (musb->gadget_driver) {
1710 		DBG(1, "%s is already bound to %s\n",
1711 				musb_driver_name,
1712 				musb->gadget_driver->driver.name);
1713 		retval = -EBUSY;
1714 	} else {
1715 		musb->gadget_driver = driver;
1716 		musb->g.dev.driver = &driver->driver;
1717 		driver->driver.bus = NULL;
1718 		musb->softconnect = 1;
1719 		retval = 0;
1720 	}
1721 
1722 	spin_unlock_irqrestore(&musb->lock, flags);
1723 
1724 	if (retval == 0) {
1725 		retval = driver->bind(&musb->g);
1726 		if (retval != 0) {
1727 			DBG(3, "bind to driver %s failed --> %d\n",
1728 					driver->driver.name, retval);
1729 			musb->gadget_driver = NULL;
1730 			musb->g.dev.driver = NULL;
1731 		}
1732 
1733 		spin_lock_irqsave(&musb->lock, flags);
1734 
1735 		otg_set_peripheral(musb->xceiv, &musb->g);
1736 		musb->xceiv->state = OTG_STATE_B_IDLE;
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