xref: /openbmc/linux/drivers/usb/musb/musb_gadget_ep0.c (revision baa7eb025ab14f3cba2e35c0a8648f9c9f01d24f)
1 /*
2  * MUSB OTG peripheral driver ep0 handling
3  *
4  * Copyright 2005 Mentor Graphics Corporation
5  * Copyright (C) 2005-2006 by Texas Instruments
6  * Copyright (C) 2006-2007 Nokia Corporation
7  * Copyright (C) 2008-2009 MontaVista Software, Inc. <source@mvista.com>
8  *
9  * This program is free software; you can redistribute it and/or
10  * modify it under the terms of the GNU General Public License
11  * version 2 as published by the Free Software Foundation.
12  *
13  * This program is distributed in the hope that it will be useful, but
14  * WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16  * General Public License for more details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this program; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
21  * 02110-1301 USA
22  *
23  * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
24  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
25  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
26  * NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
27  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
28  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
29  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
30  * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
32  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33  *
34  */
35 
36 #include <linux/kernel.h>
37 #include <linux/list.h>
38 #include <linux/timer.h>
39 #include <linux/spinlock.h>
40 #include <linux/init.h>
41 #include <linux/device.h>
42 #include <linux/interrupt.h>
43 
44 #include "musb_core.h"
45 
46 /* ep0 is always musb->endpoints[0].ep_in */
47 #define	next_ep0_request(musb)	next_in_request(&(musb)->endpoints[0])
48 
49 /*
50  * locking note:  we use only the controller lock, for simpler correctness.
51  * It's always held with IRQs blocked.
52  *
53  * It protects the ep0 request queue as well as ep0_state, not just the
54  * controller and indexed registers.  And that lock stays held unless it
55  * needs to be dropped to allow reentering this driver ... like upcalls to
56  * the gadget driver, or adjusting endpoint halt status.
57  */
58 
59 static char *decode_ep0stage(u8 stage)
60 {
61 	switch (stage) {
62 	case MUSB_EP0_STAGE_IDLE:	return "idle";
63 	case MUSB_EP0_STAGE_SETUP:	return "setup";
64 	case MUSB_EP0_STAGE_TX:		return "in";
65 	case MUSB_EP0_STAGE_RX:		return "out";
66 	case MUSB_EP0_STAGE_ACKWAIT:	return "wait";
67 	case MUSB_EP0_STAGE_STATUSIN:	return "in/status";
68 	case MUSB_EP0_STAGE_STATUSOUT:	return "out/status";
69 	default:			return "?";
70 	}
71 }
72 
73 /* handle a standard GET_STATUS request
74  * Context:  caller holds controller lock
75  */
76 static int service_tx_status_request(
77 	struct musb *musb,
78 	const struct usb_ctrlrequest *ctrlrequest)
79 {
80 	void __iomem	*mbase = musb->mregs;
81 	int handled = 1;
82 	u8 result[2], epnum = 0;
83 	const u8 recip = ctrlrequest->bRequestType & USB_RECIP_MASK;
84 
85 	result[1] = 0;
86 
87 	switch (recip) {
88 	case USB_RECIP_DEVICE:
89 		result[0] = musb->is_self_powered << USB_DEVICE_SELF_POWERED;
90 		result[0] |= musb->may_wakeup << USB_DEVICE_REMOTE_WAKEUP;
91 #ifdef CONFIG_USB_MUSB_OTG
92 		if (musb->g.is_otg) {
93 			result[0] |= musb->g.b_hnp_enable
94 				<< USB_DEVICE_B_HNP_ENABLE;
95 			result[0] |= musb->g.a_alt_hnp_support
96 				<< USB_DEVICE_A_ALT_HNP_SUPPORT;
97 			result[0] |= musb->g.a_hnp_support
98 				<< USB_DEVICE_A_HNP_SUPPORT;
99 		}
100 #endif
101 		break;
102 
103 	case USB_RECIP_INTERFACE:
104 		result[0] = 0;
105 		break;
106 
107 	case USB_RECIP_ENDPOINT: {
108 		int		is_in;
109 		struct musb_ep	*ep;
110 		u16		tmp;
111 		void __iomem	*regs;
112 
113 		epnum = (u8) ctrlrequest->wIndex;
114 		if (!epnum) {
115 			result[0] = 0;
116 			break;
117 		}
118 
119 		is_in = epnum & USB_DIR_IN;
120 		if (is_in) {
121 			epnum &= 0x0f;
122 			ep = &musb->endpoints[epnum].ep_in;
123 		} else {
124 			ep = &musb->endpoints[epnum].ep_out;
125 		}
126 		regs = musb->endpoints[epnum].regs;
127 
128 		if (epnum >= MUSB_C_NUM_EPS || !ep->desc) {
129 			handled = -EINVAL;
130 			break;
131 		}
132 
133 		musb_ep_select(mbase, epnum);
134 		if (is_in)
135 			tmp = musb_readw(regs, MUSB_TXCSR)
136 						& MUSB_TXCSR_P_SENDSTALL;
137 		else
138 			tmp = musb_readw(regs, MUSB_RXCSR)
139 						& MUSB_RXCSR_P_SENDSTALL;
140 		musb_ep_select(mbase, 0);
141 
142 		result[0] = tmp ? 1 : 0;
143 		} break;
144 
145 	default:
146 		/* class, vendor, etc ... delegate */
147 		handled = 0;
148 		break;
149 	}
150 
151 	/* fill up the fifo; caller updates csr0 */
152 	if (handled > 0) {
153 		u16	len = le16_to_cpu(ctrlrequest->wLength);
154 
155 		if (len > 2)
156 			len = 2;
157 		musb_write_fifo(&musb->endpoints[0], len, result);
158 	}
159 
160 	return handled;
161 }
162 
163 /*
164  * handle a control-IN request, the end0 buffer contains the current request
165  * that is supposed to be a standard control request. Assumes the fifo to
166  * be at least 2 bytes long.
167  *
168  * @return 0 if the request was NOT HANDLED,
169  * < 0 when error
170  * > 0 when the request is processed
171  *
172  * Context:  caller holds controller lock
173  */
174 static int
175 service_in_request(struct musb *musb, const struct usb_ctrlrequest *ctrlrequest)
176 {
177 	int handled = 0;	/* not handled */
178 
179 	if ((ctrlrequest->bRequestType & USB_TYPE_MASK)
180 			== USB_TYPE_STANDARD) {
181 		switch (ctrlrequest->bRequest) {
182 		case USB_REQ_GET_STATUS:
183 			handled = service_tx_status_request(musb,
184 					ctrlrequest);
185 			break;
186 
187 		/* case USB_REQ_SYNC_FRAME: */
188 
189 		default:
190 			break;
191 		}
192 	}
193 	return handled;
194 }
195 
196 /*
197  * Context:  caller holds controller lock
198  */
199 static void musb_g_ep0_giveback(struct musb *musb, struct usb_request *req)
200 {
201 	musb_g_giveback(&musb->endpoints[0].ep_in, req, 0);
202 }
203 
204 /*
205  * Tries to start B-device HNP negotiation if enabled via sysfs
206  */
207 static inline void musb_try_b_hnp_enable(struct musb *musb)
208 {
209 	void __iomem	*mbase = musb->mregs;
210 	u8		devctl;
211 
212 	DBG(1, "HNP: Setting HR\n");
213 	devctl = musb_readb(mbase, MUSB_DEVCTL);
214 	musb_writeb(mbase, MUSB_DEVCTL, devctl | MUSB_DEVCTL_HR);
215 }
216 
217 /*
218  * Handle all control requests with no DATA stage, including standard
219  * requests such as:
220  * USB_REQ_SET_CONFIGURATION, USB_REQ_SET_INTERFACE, unrecognized
221  *	always delegated to the gadget driver
222  * USB_REQ_SET_ADDRESS, USB_REQ_CLEAR_FEATURE, USB_REQ_SET_FEATURE
223  *	always handled here, except for class/vendor/... features
224  *
225  * Context:  caller holds controller lock
226  */
227 static int
228 service_zero_data_request(struct musb *musb,
229 		struct usb_ctrlrequest *ctrlrequest)
230 __releases(musb->lock)
231 __acquires(musb->lock)
232 {
233 	int handled = -EINVAL;
234 	void __iomem *mbase = musb->mregs;
235 	const u8 recip = ctrlrequest->bRequestType & USB_RECIP_MASK;
236 
237 	/* the gadget driver handles everything except what we MUST handle */
238 	if ((ctrlrequest->bRequestType & USB_TYPE_MASK)
239 			== USB_TYPE_STANDARD) {
240 		switch (ctrlrequest->bRequest) {
241 		case USB_REQ_SET_ADDRESS:
242 			/* change it after the status stage */
243 			musb->set_address = true;
244 			musb->address = (u8) (ctrlrequest->wValue & 0x7f);
245 			handled = 1;
246 			break;
247 
248 		case USB_REQ_CLEAR_FEATURE:
249 			switch (recip) {
250 			case USB_RECIP_DEVICE:
251 				if (ctrlrequest->wValue
252 						!= USB_DEVICE_REMOTE_WAKEUP)
253 					break;
254 				musb->may_wakeup = 0;
255 				handled = 1;
256 				break;
257 			case USB_RECIP_INTERFACE:
258 				break;
259 			case USB_RECIP_ENDPOINT:{
260 				const u8		epnum =
261 					ctrlrequest->wIndex & 0x0f;
262 				struct musb_ep		*musb_ep;
263 				struct musb_hw_ep	*ep;
264 				struct musb_request	*request;
265 				void __iomem		*regs;
266 				int			is_in;
267 				u16			csr;
268 
269 				if (epnum == 0 || epnum >= MUSB_C_NUM_EPS ||
270 				    ctrlrequest->wValue != USB_ENDPOINT_HALT)
271 					break;
272 
273 				ep = musb->endpoints + epnum;
274 				regs = ep->regs;
275 				is_in = ctrlrequest->wIndex & USB_DIR_IN;
276 				if (is_in)
277 					musb_ep = &ep->ep_in;
278 				else
279 					musb_ep = &ep->ep_out;
280 				if (!musb_ep->desc)
281 					break;
282 
283 				handled = 1;
284 				/* Ignore request if endpoint is wedged */
285 				if (musb_ep->wedged)
286 					break;
287 
288 				musb_ep_select(mbase, epnum);
289 				if (is_in) {
290 					csr  = musb_readw(regs, MUSB_TXCSR);
291 					csr |= MUSB_TXCSR_CLRDATATOG |
292 					       MUSB_TXCSR_P_WZC_BITS;
293 					csr &= ~(MUSB_TXCSR_P_SENDSTALL |
294 						 MUSB_TXCSR_P_SENTSTALL |
295 						 MUSB_TXCSR_TXPKTRDY);
296 					musb_writew(regs, MUSB_TXCSR, csr);
297 				} else {
298 					csr  = musb_readw(regs, MUSB_RXCSR);
299 					csr |= MUSB_RXCSR_CLRDATATOG |
300 					       MUSB_RXCSR_P_WZC_BITS;
301 					csr &= ~(MUSB_RXCSR_P_SENDSTALL |
302 						 MUSB_RXCSR_P_SENTSTALL);
303 					musb_writew(regs, MUSB_RXCSR, csr);
304 				}
305 
306 				/* Maybe start the first request in the queue */
307 				request = to_musb_request(
308 						next_request(musb_ep));
309 				if (!musb_ep->busy && request) {
310 					DBG(3, "restarting the request\n");
311 					musb_ep_restart(musb, request);
312 				}
313 
314 				/* select ep0 again */
315 				musb_ep_select(mbase, 0);
316 				} break;
317 			default:
318 				/* class, vendor, etc ... delegate */
319 				handled = 0;
320 				break;
321 			}
322 			break;
323 
324 		case USB_REQ_SET_FEATURE:
325 			switch (recip) {
326 			case USB_RECIP_DEVICE:
327 				handled = 1;
328 				switch (ctrlrequest->wValue) {
329 				case USB_DEVICE_REMOTE_WAKEUP:
330 					musb->may_wakeup = 1;
331 					break;
332 				case USB_DEVICE_TEST_MODE:
333 					if (musb->g.speed != USB_SPEED_HIGH)
334 						goto stall;
335 					if (ctrlrequest->wIndex & 0xff)
336 						goto stall;
337 
338 					switch (ctrlrequest->wIndex >> 8) {
339 					case 1:
340 						pr_debug("TEST_J\n");
341 						/* TEST_J */
342 						musb->test_mode_nr =
343 							MUSB_TEST_J;
344 						break;
345 					case 2:
346 						/* TEST_K */
347 						pr_debug("TEST_K\n");
348 						musb->test_mode_nr =
349 							MUSB_TEST_K;
350 						break;
351 					case 3:
352 						/* TEST_SE0_NAK */
353 						pr_debug("TEST_SE0_NAK\n");
354 						musb->test_mode_nr =
355 							MUSB_TEST_SE0_NAK;
356 						break;
357 					case 4:
358 						/* TEST_PACKET */
359 						pr_debug("TEST_PACKET\n");
360 						musb->test_mode_nr =
361 							MUSB_TEST_PACKET;
362 						break;
363 
364 					case 0xc0:
365 						/* TEST_FORCE_HS */
366 						pr_debug("TEST_FORCE_HS\n");
367 						musb->test_mode_nr =
368 							MUSB_TEST_FORCE_HS;
369 						break;
370 					case 0xc1:
371 						/* TEST_FORCE_FS */
372 						pr_debug("TEST_FORCE_FS\n");
373 						musb->test_mode_nr =
374 							MUSB_TEST_FORCE_FS;
375 						break;
376 					case 0xc2:
377 						/* TEST_FIFO_ACCESS */
378 						pr_debug("TEST_FIFO_ACCESS\n");
379 						musb->test_mode_nr =
380 							MUSB_TEST_FIFO_ACCESS;
381 						break;
382 					case 0xc3:
383 						/* TEST_FORCE_HOST */
384 						pr_debug("TEST_FORCE_HOST\n");
385 						musb->test_mode_nr =
386 							MUSB_TEST_FORCE_HOST;
387 						break;
388 					default:
389 						goto stall;
390 					}
391 
392 					/* enter test mode after irq */
393 					if (handled > 0)
394 						musb->test_mode = true;
395 					break;
396 #ifdef CONFIG_USB_MUSB_OTG
397 				case USB_DEVICE_B_HNP_ENABLE:
398 					if (!musb->g.is_otg)
399 						goto stall;
400 					musb->g.b_hnp_enable = 1;
401 					musb_try_b_hnp_enable(musb);
402 					break;
403 				case USB_DEVICE_A_HNP_SUPPORT:
404 					if (!musb->g.is_otg)
405 						goto stall;
406 					musb->g.a_hnp_support = 1;
407 					break;
408 				case USB_DEVICE_A_ALT_HNP_SUPPORT:
409 					if (!musb->g.is_otg)
410 						goto stall;
411 					musb->g.a_alt_hnp_support = 1;
412 					break;
413 #endif
414 				case USB_DEVICE_DEBUG_MODE:
415 					handled = 0;
416 					break;
417 stall:
418 				default:
419 					handled = -EINVAL;
420 					break;
421 				}
422 				break;
423 
424 			case USB_RECIP_INTERFACE:
425 				break;
426 
427 			case USB_RECIP_ENDPOINT:{
428 				const u8		epnum =
429 					ctrlrequest->wIndex & 0x0f;
430 				struct musb_ep		*musb_ep;
431 				struct musb_hw_ep	*ep;
432 				void __iomem		*regs;
433 				int			is_in;
434 				u16			csr;
435 
436 				if (epnum == 0 || epnum >= MUSB_C_NUM_EPS ||
437 				    ctrlrequest->wValue	!= USB_ENDPOINT_HALT)
438 					break;
439 
440 				ep = musb->endpoints + epnum;
441 				regs = ep->regs;
442 				is_in = ctrlrequest->wIndex & USB_DIR_IN;
443 				if (is_in)
444 					musb_ep = &ep->ep_in;
445 				else
446 					musb_ep = &ep->ep_out;
447 				if (!musb_ep->desc)
448 					break;
449 
450 				musb_ep_select(mbase, epnum);
451 				if (is_in) {
452 					csr = musb_readw(regs, MUSB_TXCSR);
453 					if (csr & MUSB_TXCSR_FIFONOTEMPTY)
454 						csr |= MUSB_TXCSR_FLUSHFIFO;
455 					csr |= MUSB_TXCSR_P_SENDSTALL
456 						| MUSB_TXCSR_CLRDATATOG
457 						| MUSB_TXCSR_P_WZC_BITS;
458 					musb_writew(regs, MUSB_TXCSR, csr);
459 				} else {
460 					csr = musb_readw(regs, MUSB_RXCSR);
461 					csr |= MUSB_RXCSR_P_SENDSTALL
462 						| MUSB_RXCSR_FLUSHFIFO
463 						| MUSB_RXCSR_CLRDATATOG
464 						| MUSB_RXCSR_P_WZC_BITS;
465 					musb_writew(regs, MUSB_RXCSR, csr);
466 				}
467 
468 				/* select ep0 again */
469 				musb_ep_select(mbase, 0);
470 				handled = 1;
471 				} break;
472 
473 			default:
474 				/* class, vendor, etc ... delegate */
475 				handled = 0;
476 				break;
477 			}
478 			break;
479 		default:
480 			/* delegate SET_CONFIGURATION, etc */
481 			handled = 0;
482 		}
483 	} else
484 		handled = 0;
485 	return handled;
486 }
487 
488 /* we have an ep0out data packet
489  * Context:  caller holds controller lock
490  */
491 static void ep0_rxstate(struct musb *musb)
492 {
493 	void __iomem		*regs = musb->control_ep->regs;
494 	struct usb_request	*req;
495 	u16			count, csr;
496 
497 	req = next_ep0_request(musb);
498 
499 	/* read packet and ack; or stall because of gadget driver bug:
500 	 * should have provided the rx buffer before setup() returned.
501 	 */
502 	if (req) {
503 		void		*buf = req->buf + req->actual;
504 		unsigned	len = req->length - req->actual;
505 
506 		/* read the buffer */
507 		count = musb_readb(regs, MUSB_COUNT0);
508 		if (count > len) {
509 			req->status = -EOVERFLOW;
510 			count = len;
511 		}
512 		musb_read_fifo(&musb->endpoints[0], count, buf);
513 		req->actual += count;
514 		csr = MUSB_CSR0_P_SVDRXPKTRDY;
515 		if (count < 64 || req->actual == req->length) {
516 			musb->ep0_state = MUSB_EP0_STAGE_STATUSIN;
517 			csr |= MUSB_CSR0_P_DATAEND;
518 		} else
519 			req = NULL;
520 	} else
521 		csr = MUSB_CSR0_P_SVDRXPKTRDY | MUSB_CSR0_P_SENDSTALL;
522 
523 
524 	/* Completion handler may choose to stall, e.g. because the
525 	 * message just received holds invalid data.
526 	 */
527 	if (req) {
528 		musb->ackpend = csr;
529 		musb_g_ep0_giveback(musb, req);
530 		if (!musb->ackpend)
531 			return;
532 		musb->ackpend = 0;
533 	}
534 	musb_ep_select(musb->mregs, 0);
535 	musb_writew(regs, MUSB_CSR0, csr);
536 }
537 
538 /*
539  * transmitting to the host (IN), this code might be called from IRQ
540  * and from kernel thread.
541  *
542  * Context:  caller holds controller lock
543  */
544 static void ep0_txstate(struct musb *musb)
545 {
546 	void __iomem		*regs = musb->control_ep->regs;
547 	struct usb_request	*request = next_ep0_request(musb);
548 	u16			csr = MUSB_CSR0_TXPKTRDY;
549 	u8			*fifo_src;
550 	u8			fifo_count;
551 
552 	if (!request) {
553 		/* WARN_ON(1); */
554 		DBG(2, "odd; csr0 %04x\n", musb_readw(regs, MUSB_CSR0));
555 		return;
556 	}
557 
558 	/* load the data */
559 	fifo_src = (u8 *) request->buf + request->actual;
560 	fifo_count = min((unsigned) MUSB_EP0_FIFOSIZE,
561 		request->length - request->actual);
562 	musb_write_fifo(&musb->endpoints[0], fifo_count, fifo_src);
563 	request->actual += fifo_count;
564 
565 	/* update the flags */
566 	if (fifo_count < MUSB_MAX_END0_PACKET
567 			|| (request->actual == request->length
568 				&& !request->zero)) {
569 		musb->ep0_state = MUSB_EP0_STAGE_STATUSOUT;
570 		csr |= MUSB_CSR0_P_DATAEND;
571 	} else
572 		request = NULL;
573 
574 	/* report completions as soon as the fifo's loaded; there's no
575 	 * win in waiting till this last packet gets acked.  (other than
576 	 * very precise fault reporting, needed by USB TMC; possible with
577 	 * this hardware, but not usable from portable gadget drivers.)
578 	 */
579 	if (request) {
580 		musb->ackpend = csr;
581 		musb_g_ep0_giveback(musb, request);
582 		if (!musb->ackpend)
583 			return;
584 		musb->ackpend = 0;
585 	}
586 
587 	/* send it out, triggering a "txpktrdy cleared" irq */
588 	musb_ep_select(musb->mregs, 0);
589 	musb_writew(regs, MUSB_CSR0, csr);
590 }
591 
592 /*
593  * Read a SETUP packet (struct usb_ctrlrequest) from the hardware.
594  * Fields are left in USB byte-order.
595  *
596  * Context:  caller holds controller lock.
597  */
598 static void
599 musb_read_setup(struct musb *musb, struct usb_ctrlrequest *req)
600 {
601 	struct usb_request	*r;
602 	void __iomem		*regs = musb->control_ep->regs;
603 
604 	musb_read_fifo(&musb->endpoints[0], sizeof *req, (u8 *)req);
605 
606 	/* NOTE:  earlier 2.6 versions changed setup packets to host
607 	 * order, but now USB packets always stay in USB byte order.
608 	 */
609 	DBG(3, "SETUP req%02x.%02x v%04x i%04x l%d\n",
610 		req->bRequestType,
611 		req->bRequest,
612 		le16_to_cpu(req->wValue),
613 		le16_to_cpu(req->wIndex),
614 		le16_to_cpu(req->wLength));
615 
616 	/* clean up any leftover transfers */
617 	r = next_ep0_request(musb);
618 	if (r)
619 		musb_g_ep0_giveback(musb, r);
620 
621 	/* For zero-data requests we want to delay the STATUS stage to
622 	 * avoid SETUPEND errors.  If we read data (OUT), delay accepting
623 	 * packets until there's a buffer to store them in.
624 	 *
625 	 * If we write data, the controller acts happier if we enable
626 	 * the TX FIFO right away, and give the controller a moment
627 	 * to switch modes...
628 	 */
629 	musb->set_address = false;
630 	musb->ackpend = MUSB_CSR0_P_SVDRXPKTRDY;
631 	if (req->wLength == 0) {
632 		if (req->bRequestType & USB_DIR_IN)
633 			musb->ackpend |= MUSB_CSR0_TXPKTRDY;
634 		musb->ep0_state = MUSB_EP0_STAGE_ACKWAIT;
635 	} else if (req->bRequestType & USB_DIR_IN) {
636 		musb->ep0_state = MUSB_EP0_STAGE_TX;
637 		musb_writew(regs, MUSB_CSR0, MUSB_CSR0_P_SVDRXPKTRDY);
638 		while ((musb_readw(regs, MUSB_CSR0)
639 				& MUSB_CSR0_RXPKTRDY) != 0)
640 			cpu_relax();
641 		musb->ackpend = 0;
642 	} else
643 		musb->ep0_state = MUSB_EP0_STAGE_RX;
644 }
645 
646 static int
647 forward_to_driver(struct musb *musb, const struct usb_ctrlrequest *ctrlrequest)
648 __releases(musb->lock)
649 __acquires(musb->lock)
650 {
651 	int retval;
652 	if (!musb->gadget_driver)
653 		return -EOPNOTSUPP;
654 	spin_unlock(&musb->lock);
655 	retval = musb->gadget_driver->setup(&musb->g, ctrlrequest);
656 	spin_lock(&musb->lock);
657 	return retval;
658 }
659 
660 /*
661  * Handle peripheral ep0 interrupt
662  *
663  * Context: irq handler; we won't re-enter the driver that way.
664  */
665 irqreturn_t musb_g_ep0_irq(struct musb *musb)
666 {
667 	u16		csr;
668 	u16		len;
669 	void __iomem	*mbase = musb->mregs;
670 	void __iomem	*regs = musb->endpoints[0].regs;
671 	irqreturn_t	retval = IRQ_NONE;
672 
673 	musb_ep_select(mbase, 0);	/* select ep0 */
674 	csr = musb_readw(regs, MUSB_CSR0);
675 	len = musb_readb(regs, MUSB_COUNT0);
676 
677 	DBG(4, "csr %04x, count %d, myaddr %d, ep0stage %s\n",
678 			csr, len,
679 			musb_readb(mbase, MUSB_FADDR),
680 			decode_ep0stage(musb->ep0_state));
681 
682 	/* I sent a stall.. need to acknowledge it now.. */
683 	if (csr & MUSB_CSR0_P_SENTSTALL) {
684 		musb_writew(regs, MUSB_CSR0,
685 				csr & ~MUSB_CSR0_P_SENTSTALL);
686 		retval = IRQ_HANDLED;
687 		musb->ep0_state = MUSB_EP0_STAGE_IDLE;
688 		csr = musb_readw(regs, MUSB_CSR0);
689 	}
690 
691 	/* request ended "early" */
692 	if (csr & MUSB_CSR0_P_SETUPEND) {
693 		musb_writew(regs, MUSB_CSR0, MUSB_CSR0_P_SVDSETUPEND);
694 		retval = IRQ_HANDLED;
695 		/* Transition into the early status phase */
696 		switch (musb->ep0_state) {
697 		case MUSB_EP0_STAGE_TX:
698 			musb->ep0_state = MUSB_EP0_STAGE_STATUSOUT;
699 			break;
700 		case MUSB_EP0_STAGE_RX:
701 			musb->ep0_state = MUSB_EP0_STAGE_STATUSIN;
702 			break;
703 		default:
704 			ERR("SetupEnd came in a wrong ep0stage %s\n",
705 			    decode_ep0stage(musb->ep0_state));
706 		}
707 		csr = musb_readw(regs, MUSB_CSR0);
708 		/* NOTE:  request may need completion */
709 	}
710 
711 	/* docs from Mentor only describe tx, rx, and idle/setup states.
712 	 * we need to handle nuances around status stages, and also the
713 	 * case where status and setup stages come back-to-back ...
714 	 */
715 	switch (musb->ep0_state) {
716 
717 	case MUSB_EP0_STAGE_TX:
718 		/* irq on clearing txpktrdy */
719 		if ((csr & MUSB_CSR0_TXPKTRDY) == 0) {
720 			ep0_txstate(musb);
721 			retval = IRQ_HANDLED;
722 		}
723 		break;
724 
725 	case MUSB_EP0_STAGE_RX:
726 		/* irq on set rxpktrdy */
727 		if (csr & MUSB_CSR0_RXPKTRDY) {
728 			ep0_rxstate(musb);
729 			retval = IRQ_HANDLED;
730 		}
731 		break;
732 
733 	case MUSB_EP0_STAGE_STATUSIN:
734 		/* end of sequence #2 (OUT/RX state) or #3 (no data) */
735 
736 		/* update address (if needed) only @ the end of the
737 		 * status phase per usb spec, which also guarantees
738 		 * we get 10 msec to receive this irq... until this
739 		 * is done we won't see the next packet.
740 		 */
741 		if (musb->set_address) {
742 			musb->set_address = false;
743 			musb_writeb(mbase, MUSB_FADDR, musb->address);
744 		}
745 
746 		/* enter test mode if needed (exit by reset) */
747 		else if (musb->test_mode) {
748 			DBG(1, "entering TESTMODE\n");
749 
750 			if (MUSB_TEST_PACKET == musb->test_mode_nr)
751 				musb_load_testpacket(musb);
752 
753 			musb_writeb(mbase, MUSB_TESTMODE,
754 					musb->test_mode_nr);
755 		}
756 		/* FALLTHROUGH */
757 
758 	case MUSB_EP0_STAGE_STATUSOUT:
759 		/* end of sequence #1: write to host (TX state) */
760 		{
761 			struct usb_request	*req;
762 
763 			req = next_ep0_request(musb);
764 			if (req)
765 				musb_g_ep0_giveback(musb, req);
766 		}
767 
768 		/*
769 		 * In case when several interrupts can get coalesced,
770 		 * check to see if we've already received a SETUP packet...
771 		 */
772 		if (csr & MUSB_CSR0_RXPKTRDY)
773 			goto setup;
774 
775 		retval = IRQ_HANDLED;
776 		musb->ep0_state = MUSB_EP0_STAGE_IDLE;
777 		break;
778 
779 	case MUSB_EP0_STAGE_IDLE:
780 		/*
781 		 * This state is typically (but not always) indiscernible
782 		 * from the status states since the corresponding interrupts
783 		 * tend to happen within too little period of time (with only
784 		 * a zero-length packet in between) and so get coalesced...
785 		 */
786 		retval = IRQ_HANDLED;
787 		musb->ep0_state = MUSB_EP0_STAGE_SETUP;
788 		/* FALLTHROUGH */
789 
790 	case MUSB_EP0_STAGE_SETUP:
791 setup:
792 		if (csr & MUSB_CSR0_RXPKTRDY) {
793 			struct usb_ctrlrequest	setup;
794 			int			handled = 0;
795 
796 			if (len != 8) {
797 				ERR("SETUP packet len %d != 8 ?\n", len);
798 				break;
799 			}
800 			musb_read_setup(musb, &setup);
801 			retval = IRQ_HANDLED;
802 
803 			/* sometimes the RESET won't be reported */
804 			if (unlikely(musb->g.speed == USB_SPEED_UNKNOWN)) {
805 				u8	power;
806 
807 				printk(KERN_NOTICE "%s: peripheral reset "
808 						"irq lost!\n",
809 						musb_driver_name);
810 				power = musb_readb(mbase, MUSB_POWER);
811 				musb->g.speed = (power & MUSB_POWER_HSMODE)
812 					? USB_SPEED_HIGH : USB_SPEED_FULL;
813 
814 			}
815 
816 			switch (musb->ep0_state) {
817 
818 			/* sequence #3 (no data stage), includes requests
819 			 * we can't forward (notably SET_ADDRESS and the
820 			 * device/endpoint feature set/clear operations)
821 			 * plus SET_CONFIGURATION and others we must
822 			 */
823 			case MUSB_EP0_STAGE_ACKWAIT:
824 				handled = service_zero_data_request(
825 						musb, &setup);
826 
827 				/*
828 				 * We're expecting no data in any case, so
829 				 * always set the DATAEND bit -- doing this
830 				 * here helps avoid SetupEnd interrupt coming
831 				 * in the idle stage when we're stalling...
832 				 */
833 				musb->ackpend |= MUSB_CSR0_P_DATAEND;
834 
835 				/* status stage might be immediate */
836 				if (handled > 0)
837 					musb->ep0_state =
838 						MUSB_EP0_STAGE_STATUSIN;
839 				break;
840 
841 			/* sequence #1 (IN to host), includes GET_STATUS
842 			 * requests that we can't forward, GET_DESCRIPTOR
843 			 * and others that we must
844 			 */
845 			case MUSB_EP0_STAGE_TX:
846 				handled = service_in_request(musb, &setup);
847 				if (handled > 0) {
848 					musb->ackpend = MUSB_CSR0_TXPKTRDY
849 						| MUSB_CSR0_P_DATAEND;
850 					musb->ep0_state =
851 						MUSB_EP0_STAGE_STATUSOUT;
852 				}
853 				break;
854 
855 			/* sequence #2 (OUT from host), always forward */
856 			default:		/* MUSB_EP0_STAGE_RX */
857 				break;
858 			}
859 
860 			DBG(3, "handled %d, csr %04x, ep0stage %s\n",
861 				handled, csr,
862 				decode_ep0stage(musb->ep0_state));
863 
864 			/* unless we need to delegate this to the gadget
865 			 * driver, we know how to wrap this up:  csr0 has
866 			 * not yet been written.
867 			 */
868 			if (handled < 0)
869 				goto stall;
870 			else if (handled > 0)
871 				goto finish;
872 
873 			handled = forward_to_driver(musb, &setup);
874 			if (handled < 0) {
875 				musb_ep_select(mbase, 0);
876 stall:
877 				DBG(3, "stall (%d)\n", handled);
878 				musb->ackpend |= MUSB_CSR0_P_SENDSTALL;
879 				musb->ep0_state = MUSB_EP0_STAGE_IDLE;
880 finish:
881 				musb_writew(regs, MUSB_CSR0,
882 						musb->ackpend);
883 				musb->ackpend = 0;
884 			}
885 		}
886 		break;
887 
888 	case MUSB_EP0_STAGE_ACKWAIT:
889 		/* This should not happen. But happens with tusb6010 with
890 		 * g_file_storage and high speed. Do nothing.
891 		 */
892 		retval = IRQ_HANDLED;
893 		break;
894 
895 	default:
896 		/* "can't happen" */
897 		WARN_ON(1);
898 		musb_writew(regs, MUSB_CSR0, MUSB_CSR0_P_SENDSTALL);
899 		musb->ep0_state = MUSB_EP0_STAGE_IDLE;
900 		break;
901 	}
902 
903 	return retval;
904 }
905 
906 
907 static int
908 musb_g_ep0_enable(struct usb_ep *ep, const struct usb_endpoint_descriptor *desc)
909 {
910 	/* always enabled */
911 	return -EINVAL;
912 }
913 
914 static int musb_g_ep0_disable(struct usb_ep *e)
915 {
916 	/* always enabled */
917 	return -EINVAL;
918 }
919 
920 static int
921 musb_g_ep0_queue(struct usb_ep *e, struct usb_request *r, gfp_t gfp_flags)
922 {
923 	struct musb_ep		*ep;
924 	struct musb_request	*req;
925 	struct musb		*musb;
926 	int			status;
927 	unsigned long		lockflags;
928 	void __iomem		*regs;
929 
930 	if (!e || !r)
931 		return -EINVAL;
932 
933 	ep = to_musb_ep(e);
934 	musb = ep->musb;
935 	regs = musb->control_ep->regs;
936 
937 	req = to_musb_request(r);
938 	req->musb = musb;
939 	req->request.actual = 0;
940 	req->request.status = -EINPROGRESS;
941 	req->tx = ep->is_in;
942 
943 	spin_lock_irqsave(&musb->lock, lockflags);
944 
945 	if (!list_empty(&ep->req_list)) {
946 		status = -EBUSY;
947 		goto cleanup;
948 	}
949 
950 	switch (musb->ep0_state) {
951 	case MUSB_EP0_STAGE_RX:		/* control-OUT data */
952 	case MUSB_EP0_STAGE_TX:		/* control-IN data */
953 	case MUSB_EP0_STAGE_ACKWAIT:	/* zero-length data */
954 		status = 0;
955 		break;
956 	default:
957 		DBG(1, "ep0 request queued in state %d\n",
958 				musb->ep0_state);
959 		status = -EINVAL;
960 		goto cleanup;
961 	}
962 
963 	/* add request to the list */
964 	list_add_tail(&(req->request.list), &(ep->req_list));
965 
966 	DBG(3, "queue to %s (%s), length=%d\n",
967 			ep->name, ep->is_in ? "IN/TX" : "OUT/RX",
968 			req->request.length);
969 
970 	musb_ep_select(musb->mregs, 0);
971 
972 	/* sequence #1, IN ... start writing the data */
973 	if (musb->ep0_state == MUSB_EP0_STAGE_TX)
974 		ep0_txstate(musb);
975 
976 	/* sequence #3, no-data ... issue IN status */
977 	else if (musb->ep0_state == MUSB_EP0_STAGE_ACKWAIT) {
978 		if (req->request.length)
979 			status = -EINVAL;
980 		else {
981 			musb->ep0_state = MUSB_EP0_STAGE_STATUSIN;
982 			musb_writew(regs, MUSB_CSR0,
983 					musb->ackpend | MUSB_CSR0_P_DATAEND);
984 			musb->ackpend = 0;
985 			musb_g_ep0_giveback(ep->musb, r);
986 		}
987 
988 	/* else for sequence #2 (OUT), caller provides a buffer
989 	 * before the next packet arrives.  deferred responses
990 	 * (after SETUP is acked) are racey.
991 	 */
992 	} else if (musb->ackpend) {
993 		musb_writew(regs, MUSB_CSR0, musb->ackpend);
994 		musb->ackpend = 0;
995 	}
996 
997 cleanup:
998 	spin_unlock_irqrestore(&musb->lock, lockflags);
999 	return status;
1000 }
1001 
1002 static int musb_g_ep0_dequeue(struct usb_ep *ep, struct usb_request *req)
1003 {
1004 	/* we just won't support this */
1005 	return -EINVAL;
1006 }
1007 
1008 static int musb_g_ep0_halt(struct usb_ep *e, int value)
1009 {
1010 	struct musb_ep		*ep;
1011 	struct musb		*musb;
1012 	void __iomem		*base, *regs;
1013 	unsigned long		flags;
1014 	int			status;
1015 	u16			csr;
1016 
1017 	if (!e || !value)
1018 		return -EINVAL;
1019 
1020 	ep = to_musb_ep(e);
1021 	musb = ep->musb;
1022 	base = musb->mregs;
1023 	regs = musb->control_ep->regs;
1024 	status = 0;
1025 
1026 	spin_lock_irqsave(&musb->lock, flags);
1027 
1028 	if (!list_empty(&ep->req_list)) {
1029 		status = -EBUSY;
1030 		goto cleanup;
1031 	}
1032 
1033 	musb_ep_select(base, 0);
1034 	csr = musb->ackpend;
1035 
1036 	switch (musb->ep0_state) {
1037 
1038 	/* Stalls are usually issued after parsing SETUP packet, either
1039 	 * directly in irq context from setup() or else later.
1040 	 */
1041 	case MUSB_EP0_STAGE_TX:		/* control-IN data */
1042 	case MUSB_EP0_STAGE_ACKWAIT:	/* STALL for zero-length data */
1043 	case MUSB_EP0_STAGE_RX:		/* control-OUT data */
1044 		csr = musb_readw(regs, MUSB_CSR0);
1045 		/* FALLTHROUGH */
1046 
1047 	/* It's also OK to issue stalls during callbacks when a non-empty
1048 	 * DATA stage buffer has been read (or even written).
1049 	 */
1050 	case MUSB_EP0_STAGE_STATUSIN:	/* control-OUT status */
1051 	case MUSB_EP0_STAGE_STATUSOUT:	/* control-IN status */
1052 
1053 		csr |= MUSB_CSR0_P_SENDSTALL;
1054 		musb_writew(regs, MUSB_CSR0, csr);
1055 		musb->ep0_state = MUSB_EP0_STAGE_IDLE;
1056 		musb->ackpend = 0;
1057 		break;
1058 	default:
1059 		DBG(1, "ep0 can't halt in state %d\n", musb->ep0_state);
1060 		status = -EINVAL;
1061 	}
1062 
1063 cleanup:
1064 	spin_unlock_irqrestore(&musb->lock, flags);
1065 	return status;
1066 }
1067 
1068 const struct usb_ep_ops musb_g_ep0_ops = {
1069 	.enable		= musb_g_ep0_enable,
1070 	.disable	= musb_g_ep0_disable,
1071 	.alloc_request	= musb_alloc_request,
1072 	.free_request	= musb_free_request,
1073 	.queue		= musb_g_ep0_queue,
1074 	.dequeue	= musb_g_ep0_dequeue,
1075 	.set_halt	= musb_g_ep0_halt,
1076 };
1077