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 	musb->ep0_state = MUSB_EP0_STAGE_SETUP;
203 }
204 
205 /*
206  * Tries to start B-device HNP negotiation if enabled via sysfs
207  */
208 static inline void musb_try_b_hnp_enable(struct musb *musb)
209 {
210 	void __iomem	*mbase = musb->mregs;
211 	u8		devctl;
212 
213 	DBG(1, "HNP: Setting HR\n");
214 	devctl = musb_readb(mbase, MUSB_DEVCTL);
215 	musb_writeb(mbase, MUSB_DEVCTL, devctl | MUSB_DEVCTL_HR);
216 }
217 
218 /*
219  * Handle all control requests with no DATA stage, including standard
220  * requests such as:
221  * USB_REQ_SET_CONFIGURATION, USB_REQ_SET_INTERFACE, unrecognized
222  *	always delegated to the gadget driver
223  * USB_REQ_SET_ADDRESS, USB_REQ_CLEAR_FEATURE, USB_REQ_SET_FEATURE
224  *	always handled here, except for class/vendor/... features
225  *
226  * Context:  caller holds controller lock
227  */
228 static int
229 service_zero_data_request(struct musb *musb,
230 		struct usb_ctrlrequest *ctrlrequest)
231 __releases(musb->lock)
232 __acquires(musb->lock)
233 {
234 	int handled = -EINVAL;
235 	void __iomem *mbase = musb->mregs;
236 	const u8 recip = ctrlrequest->bRequestType & USB_RECIP_MASK;
237 
238 	/* the gadget driver handles everything except what we MUST handle */
239 	if ((ctrlrequest->bRequestType & USB_TYPE_MASK)
240 			== USB_TYPE_STANDARD) {
241 		switch (ctrlrequest->bRequest) {
242 		case USB_REQ_SET_ADDRESS:
243 			/* change it after the status stage */
244 			musb->set_address = true;
245 			musb->address = (u8) (ctrlrequest->wValue & 0x7f);
246 			handled = 1;
247 			break;
248 
249 		case USB_REQ_CLEAR_FEATURE:
250 			switch (recip) {
251 			case USB_RECIP_DEVICE:
252 				if (ctrlrequest->wValue
253 						!= USB_DEVICE_REMOTE_WAKEUP)
254 					break;
255 				musb->may_wakeup = 0;
256 				handled = 1;
257 				break;
258 			case USB_RECIP_INTERFACE:
259 				break;
260 			case USB_RECIP_ENDPOINT:{
261 				const u8 num = ctrlrequest->wIndex & 0x0f;
262 				struct musb_ep *musb_ep;
263 
264 				if (num == 0
265 						|| num >= MUSB_C_NUM_EPS
266 						|| ctrlrequest->wValue
267 							!= USB_ENDPOINT_HALT)
268 					break;
269 
270 				if (ctrlrequest->wIndex & USB_DIR_IN)
271 					musb_ep = &musb->endpoints[num].ep_in;
272 				else
273 					musb_ep = &musb->endpoints[num].ep_out;
274 				if (!musb_ep->desc)
275 					break;
276 
277 				/* REVISIT do it directly, no locking games */
278 				spin_unlock(&musb->lock);
279 				musb_gadget_set_halt(&musb_ep->end_point, 0);
280 				spin_lock(&musb->lock);
281 
282 				/* select ep0 again */
283 				musb_ep_select(mbase, 0);
284 				handled = 1;
285 				} break;
286 			default:
287 				/* class, vendor, etc ... delegate */
288 				handled = 0;
289 				break;
290 			}
291 			break;
292 
293 		case USB_REQ_SET_FEATURE:
294 			switch (recip) {
295 			case USB_RECIP_DEVICE:
296 				handled = 1;
297 				switch (ctrlrequest->wValue) {
298 				case USB_DEVICE_REMOTE_WAKEUP:
299 					musb->may_wakeup = 1;
300 					break;
301 				case USB_DEVICE_TEST_MODE:
302 					if (musb->g.speed != USB_SPEED_HIGH)
303 						goto stall;
304 					if (ctrlrequest->wIndex & 0xff)
305 						goto stall;
306 
307 					switch (ctrlrequest->wIndex >> 8) {
308 					case 1:
309 						pr_debug("TEST_J\n");
310 						/* TEST_J */
311 						musb->test_mode_nr =
312 							MUSB_TEST_J;
313 						break;
314 					case 2:
315 						/* TEST_K */
316 						pr_debug("TEST_K\n");
317 						musb->test_mode_nr =
318 							MUSB_TEST_K;
319 						break;
320 					case 3:
321 						/* TEST_SE0_NAK */
322 						pr_debug("TEST_SE0_NAK\n");
323 						musb->test_mode_nr =
324 							MUSB_TEST_SE0_NAK;
325 						break;
326 					case 4:
327 						/* TEST_PACKET */
328 						pr_debug("TEST_PACKET\n");
329 						musb->test_mode_nr =
330 							MUSB_TEST_PACKET;
331 						break;
332 					default:
333 						goto stall;
334 					}
335 
336 					/* enter test mode after irq */
337 					if (handled > 0)
338 						musb->test_mode = true;
339 					break;
340 #ifdef CONFIG_USB_MUSB_OTG
341 				case USB_DEVICE_B_HNP_ENABLE:
342 					if (!musb->g.is_otg)
343 						goto stall;
344 					musb->g.b_hnp_enable = 1;
345 					musb_try_b_hnp_enable(musb);
346 					break;
347 				case USB_DEVICE_A_HNP_SUPPORT:
348 					if (!musb->g.is_otg)
349 						goto stall;
350 					musb->g.a_hnp_support = 1;
351 					break;
352 				case USB_DEVICE_A_ALT_HNP_SUPPORT:
353 					if (!musb->g.is_otg)
354 						goto stall;
355 					musb->g.a_alt_hnp_support = 1;
356 					break;
357 #endif
358 stall:
359 				default:
360 					handled = -EINVAL;
361 					break;
362 				}
363 				break;
364 
365 			case USB_RECIP_INTERFACE:
366 				break;
367 
368 			case USB_RECIP_ENDPOINT:{
369 				const u8		epnum =
370 					ctrlrequest->wIndex & 0x0f;
371 				struct musb_ep		*musb_ep;
372 				struct musb_hw_ep	*ep;
373 				void __iomem		*regs;
374 				int			is_in;
375 				u16			csr;
376 
377 				if (epnum == 0
378 						|| epnum >= MUSB_C_NUM_EPS
379 						|| ctrlrequest->wValue
380 							!= USB_ENDPOINT_HALT)
381 					break;
382 
383 				ep = musb->endpoints + epnum;
384 				regs = ep->regs;
385 				is_in = ctrlrequest->wIndex & USB_DIR_IN;
386 				if (is_in)
387 					musb_ep = &ep->ep_in;
388 				else
389 					musb_ep = &ep->ep_out;
390 				if (!musb_ep->desc)
391 					break;
392 
393 				musb_ep_select(mbase, epnum);
394 				if (is_in) {
395 					csr = musb_readw(regs,
396 							MUSB_TXCSR);
397 					if (csr & MUSB_TXCSR_FIFONOTEMPTY)
398 						csr |= MUSB_TXCSR_FLUSHFIFO;
399 					csr |= MUSB_TXCSR_P_SENDSTALL
400 						| MUSB_TXCSR_CLRDATATOG
401 						| MUSB_TXCSR_P_WZC_BITS;
402 					musb_writew(regs, MUSB_TXCSR,
403 							csr);
404 				} else {
405 					csr = musb_readw(regs,
406 							MUSB_RXCSR);
407 					csr |= MUSB_RXCSR_P_SENDSTALL
408 						| MUSB_RXCSR_FLUSHFIFO
409 						| MUSB_RXCSR_CLRDATATOG
410 						| MUSB_RXCSR_P_WZC_BITS;
411 					musb_writew(regs, MUSB_RXCSR,
412 							csr);
413 				}
414 
415 				/* select ep0 again */
416 				musb_ep_select(mbase, 0);
417 				handled = 1;
418 				} break;
419 
420 			default:
421 				/* class, vendor, etc ... delegate */
422 				handled = 0;
423 				break;
424 			}
425 			break;
426 		default:
427 			/* delegate SET_CONFIGURATION, etc */
428 			handled = 0;
429 		}
430 	} else
431 		handled = 0;
432 	return handled;
433 }
434 
435 /* we have an ep0out data packet
436  * Context:  caller holds controller lock
437  */
438 static void ep0_rxstate(struct musb *musb)
439 {
440 	void __iomem		*regs = musb->control_ep->regs;
441 	struct usb_request	*req;
442 	u16			count, csr;
443 
444 	req = next_ep0_request(musb);
445 
446 	/* read packet and ack; or stall because of gadget driver bug:
447 	 * should have provided the rx buffer before setup() returned.
448 	 */
449 	if (req) {
450 		void		*buf = req->buf + req->actual;
451 		unsigned	len = req->length - req->actual;
452 
453 		/* read the buffer */
454 		count = musb_readb(regs, MUSB_COUNT0);
455 		if (count > len) {
456 			req->status = -EOVERFLOW;
457 			count = len;
458 		}
459 		musb_read_fifo(&musb->endpoints[0], count, buf);
460 		req->actual += count;
461 		csr = MUSB_CSR0_P_SVDRXPKTRDY;
462 		if (count < 64 || req->actual == req->length) {
463 			musb->ep0_state = MUSB_EP0_STAGE_STATUSIN;
464 			csr |= MUSB_CSR0_P_DATAEND;
465 		} else
466 			req = NULL;
467 	} else
468 		csr = MUSB_CSR0_P_SVDRXPKTRDY | MUSB_CSR0_P_SENDSTALL;
469 
470 
471 	/* Completion handler may choose to stall, e.g. because the
472 	 * message just received holds invalid data.
473 	 */
474 	if (req) {
475 		musb->ackpend = csr;
476 		musb_g_ep0_giveback(musb, req);
477 		if (!musb->ackpend)
478 			return;
479 		musb->ackpend = 0;
480 	}
481 	musb_ep_select(musb->mregs, 0);
482 	musb_writew(regs, MUSB_CSR0, csr);
483 }
484 
485 /*
486  * transmitting to the host (IN), this code might be called from IRQ
487  * and from kernel thread.
488  *
489  * Context:  caller holds controller lock
490  */
491 static void ep0_txstate(struct musb *musb)
492 {
493 	void __iomem		*regs = musb->control_ep->regs;
494 	struct usb_request	*request = next_ep0_request(musb);
495 	u16			csr = MUSB_CSR0_TXPKTRDY;
496 	u8			*fifo_src;
497 	u8			fifo_count;
498 
499 	if (!request) {
500 		/* WARN_ON(1); */
501 		DBG(2, "odd; csr0 %04x\n", musb_readw(regs, MUSB_CSR0));
502 		return;
503 	}
504 
505 	/* load the data */
506 	fifo_src = (u8 *) request->buf + request->actual;
507 	fifo_count = min((unsigned) MUSB_EP0_FIFOSIZE,
508 		request->length - request->actual);
509 	musb_write_fifo(&musb->endpoints[0], fifo_count, fifo_src);
510 	request->actual += fifo_count;
511 
512 	/* update the flags */
513 	if (fifo_count < MUSB_MAX_END0_PACKET
514 			|| request->actual == request->length) {
515 		musb->ep0_state = MUSB_EP0_STAGE_STATUSOUT;
516 		csr |= MUSB_CSR0_P_DATAEND;
517 	} else
518 		request = NULL;
519 
520 	/* report completions as soon as the fifo's loaded; there's no
521 	 * win in waiting till this last packet gets acked.  (other than
522 	 * very precise fault reporting, needed by USB TMC; possible with
523 	 * this hardware, but not usable from portable gadget drivers.)
524 	 */
525 	if (request) {
526 		musb->ackpend = csr;
527 		musb_g_ep0_giveback(musb, request);
528 		if (!musb->ackpend)
529 			return;
530 		musb->ackpend = 0;
531 	}
532 
533 	/* send it out, triggering a "txpktrdy cleared" irq */
534 	musb_ep_select(musb->mregs, 0);
535 	musb_writew(regs, MUSB_CSR0, csr);
536 }
537 
538 /*
539  * Read a SETUP packet (struct usb_ctrlrequest) from the hardware.
540  * Fields are left in USB byte-order.
541  *
542  * Context:  caller holds controller lock.
543  */
544 static void
545 musb_read_setup(struct musb *musb, struct usb_ctrlrequest *req)
546 {
547 	struct usb_request	*r;
548 	void __iomem		*regs = musb->control_ep->regs;
549 
550 	musb_read_fifo(&musb->endpoints[0], sizeof *req, (u8 *)req);
551 
552 	/* NOTE:  earlier 2.6 versions changed setup packets to host
553 	 * order, but now USB packets always stay in USB byte order.
554 	 */
555 	DBG(3, "SETUP req%02x.%02x v%04x i%04x l%d\n",
556 		req->bRequestType,
557 		req->bRequest,
558 		le16_to_cpu(req->wValue),
559 		le16_to_cpu(req->wIndex),
560 		le16_to_cpu(req->wLength));
561 
562 	/* clean up any leftover transfers */
563 	r = next_ep0_request(musb);
564 	if (r)
565 		musb_g_ep0_giveback(musb, r);
566 
567 	/* For zero-data requests we want to delay the STATUS stage to
568 	 * avoid SETUPEND errors.  If we read data (OUT), delay accepting
569 	 * packets until there's a buffer to store them in.
570 	 *
571 	 * If we write data, the controller acts happier if we enable
572 	 * the TX FIFO right away, and give the controller a moment
573 	 * to switch modes...
574 	 */
575 	musb->set_address = false;
576 	musb->ackpend = MUSB_CSR0_P_SVDRXPKTRDY;
577 	if (req->wLength == 0) {
578 		if (req->bRequestType & USB_DIR_IN)
579 			musb->ackpend |= MUSB_CSR0_TXPKTRDY;
580 		musb->ep0_state = MUSB_EP0_STAGE_ACKWAIT;
581 	} else if (req->bRequestType & USB_DIR_IN) {
582 		musb->ep0_state = MUSB_EP0_STAGE_TX;
583 		musb_writew(regs, MUSB_CSR0, MUSB_CSR0_P_SVDRXPKTRDY);
584 		while ((musb_readw(regs, MUSB_CSR0)
585 				& MUSB_CSR0_RXPKTRDY) != 0)
586 			cpu_relax();
587 		musb->ackpend = 0;
588 	} else
589 		musb->ep0_state = MUSB_EP0_STAGE_RX;
590 }
591 
592 static int
593 forward_to_driver(struct musb *musb, const struct usb_ctrlrequest *ctrlrequest)
594 __releases(musb->lock)
595 __acquires(musb->lock)
596 {
597 	int retval;
598 	if (!musb->gadget_driver)
599 		return -EOPNOTSUPP;
600 	spin_unlock(&musb->lock);
601 	retval = musb->gadget_driver->setup(&musb->g, ctrlrequest);
602 	spin_lock(&musb->lock);
603 	return retval;
604 }
605 
606 /*
607  * Handle peripheral ep0 interrupt
608  *
609  * Context: irq handler; we won't re-enter the driver that way.
610  */
611 irqreturn_t musb_g_ep0_irq(struct musb *musb)
612 {
613 	u16		csr;
614 	u16		len;
615 	void __iomem	*mbase = musb->mregs;
616 	void __iomem	*regs = musb->endpoints[0].regs;
617 	irqreturn_t	retval = IRQ_NONE;
618 
619 	musb_ep_select(mbase, 0);	/* select ep0 */
620 	csr = musb_readw(regs, MUSB_CSR0);
621 	len = musb_readb(regs, MUSB_COUNT0);
622 
623 	DBG(4, "csr %04x, count %d, myaddr %d, ep0stage %s\n",
624 			csr, len,
625 			musb_readb(mbase, MUSB_FADDR),
626 			decode_ep0stage(musb->ep0_state));
627 
628 	/* I sent a stall.. need to acknowledge it now.. */
629 	if (csr & MUSB_CSR0_P_SENTSTALL) {
630 		musb_writew(regs, MUSB_CSR0,
631 				csr & ~MUSB_CSR0_P_SENTSTALL);
632 		retval = IRQ_HANDLED;
633 		musb->ep0_state = MUSB_EP0_STAGE_IDLE;
634 		csr = musb_readw(regs, MUSB_CSR0);
635 	}
636 
637 	/* request ended "early" */
638 	if (csr & MUSB_CSR0_P_SETUPEND) {
639 		musb_writew(regs, MUSB_CSR0, MUSB_CSR0_P_SVDSETUPEND);
640 		retval = IRQ_HANDLED;
641 		/* Transition into the early status phase */
642 		switch (musb->ep0_state) {
643 		case MUSB_EP0_STAGE_TX:
644 			musb->ep0_state = MUSB_EP0_STAGE_STATUSOUT;
645 			break;
646 		case MUSB_EP0_STAGE_RX:
647 			musb->ep0_state = MUSB_EP0_STAGE_STATUSIN;
648 			break;
649 		default:
650 			ERR("SetupEnd came in a wrong ep0stage %s",
651 			    decode_ep0stage(musb->ep0_state));
652 		}
653 		csr = musb_readw(regs, MUSB_CSR0);
654 		/* NOTE:  request may need completion */
655 	}
656 
657 	/* docs from Mentor only describe tx, rx, and idle/setup states.
658 	 * we need to handle nuances around status stages, and also the
659 	 * case where status and setup stages come back-to-back ...
660 	 */
661 	switch (musb->ep0_state) {
662 
663 	case MUSB_EP0_STAGE_TX:
664 		/* irq on clearing txpktrdy */
665 		if ((csr & MUSB_CSR0_TXPKTRDY) == 0) {
666 			ep0_txstate(musb);
667 			retval = IRQ_HANDLED;
668 		}
669 		break;
670 
671 	case MUSB_EP0_STAGE_RX:
672 		/* irq on set rxpktrdy */
673 		if (csr & MUSB_CSR0_RXPKTRDY) {
674 			ep0_rxstate(musb);
675 			retval = IRQ_HANDLED;
676 		}
677 		break;
678 
679 	case MUSB_EP0_STAGE_STATUSIN:
680 		/* end of sequence #2 (OUT/RX state) or #3 (no data) */
681 
682 		/* update address (if needed) only @ the end of the
683 		 * status phase per usb spec, which also guarantees
684 		 * we get 10 msec to receive this irq... until this
685 		 * is done we won't see the next packet.
686 		 */
687 		if (musb->set_address) {
688 			musb->set_address = false;
689 			musb_writeb(mbase, MUSB_FADDR, musb->address);
690 		}
691 
692 		/* enter test mode if needed (exit by reset) */
693 		else if (musb->test_mode) {
694 			DBG(1, "entering TESTMODE\n");
695 
696 			if (MUSB_TEST_PACKET == musb->test_mode_nr)
697 				musb_load_testpacket(musb);
698 
699 			musb_writeb(mbase, MUSB_TESTMODE,
700 					musb->test_mode_nr);
701 		}
702 		/* FALLTHROUGH */
703 
704 	case MUSB_EP0_STAGE_STATUSOUT:
705 		/* end of sequence #1: write to host (TX state) */
706 		{
707 			struct usb_request	*req;
708 
709 			req = next_ep0_request(musb);
710 			if (req)
711 				musb_g_ep0_giveback(musb, req);
712 		}
713 
714 		/*
715 		 * In case when several interrupts can get coalesced,
716 		 * check to see if we've already received a SETUP packet...
717 		 */
718 		if (csr & MUSB_CSR0_RXPKTRDY)
719 			goto setup;
720 
721 		retval = IRQ_HANDLED;
722 		musb->ep0_state = MUSB_EP0_STAGE_IDLE;
723 		break;
724 
725 	case MUSB_EP0_STAGE_IDLE:
726 		/*
727 		 * This state is typically (but not always) indiscernible
728 		 * from the status states since the corresponding interrupts
729 		 * tend to happen within too little period of time (with only
730 		 * a zero-length packet in between) and so get coalesced...
731 		 */
732 		retval = IRQ_HANDLED;
733 		musb->ep0_state = MUSB_EP0_STAGE_SETUP;
734 		/* FALLTHROUGH */
735 
736 	case MUSB_EP0_STAGE_SETUP:
737 setup:
738 		if (csr & MUSB_CSR0_RXPKTRDY) {
739 			struct usb_ctrlrequest	setup;
740 			int			handled = 0;
741 
742 			if (len != 8) {
743 				ERR("SETUP packet len %d != 8 ?\n", len);
744 				break;
745 			}
746 			musb_read_setup(musb, &setup);
747 			retval = IRQ_HANDLED;
748 
749 			/* sometimes the RESET won't be reported */
750 			if (unlikely(musb->g.speed == USB_SPEED_UNKNOWN)) {
751 				u8	power;
752 
753 				printk(KERN_NOTICE "%s: peripheral reset "
754 						"irq lost!\n",
755 						musb_driver_name);
756 				power = musb_readb(mbase, MUSB_POWER);
757 				musb->g.speed = (power & MUSB_POWER_HSMODE)
758 					? USB_SPEED_HIGH : USB_SPEED_FULL;
759 
760 			}
761 
762 			switch (musb->ep0_state) {
763 
764 			/* sequence #3 (no data stage), includes requests
765 			 * we can't forward (notably SET_ADDRESS and the
766 			 * device/endpoint feature set/clear operations)
767 			 * plus SET_CONFIGURATION and others we must
768 			 */
769 			case MUSB_EP0_STAGE_ACKWAIT:
770 				handled = service_zero_data_request(
771 						musb, &setup);
772 
773 				/* status stage might be immediate */
774 				if (handled > 0) {
775 					musb->ackpend |= MUSB_CSR0_P_DATAEND;
776 					musb->ep0_state =
777 						MUSB_EP0_STAGE_STATUSIN;
778 				}
779 				break;
780 
781 			/* sequence #1 (IN to host), includes GET_STATUS
782 			 * requests that we can't forward, GET_DESCRIPTOR
783 			 * and others that we must
784 			 */
785 			case MUSB_EP0_STAGE_TX:
786 				handled = service_in_request(musb, &setup);
787 				if (handled > 0) {
788 					musb->ackpend = MUSB_CSR0_TXPKTRDY
789 						| MUSB_CSR0_P_DATAEND;
790 					musb->ep0_state =
791 						MUSB_EP0_STAGE_STATUSOUT;
792 				}
793 				break;
794 
795 			/* sequence #2 (OUT from host), always forward */
796 			default:		/* MUSB_EP0_STAGE_RX */
797 				break;
798 			}
799 
800 			DBG(3, "handled %d, csr %04x, ep0stage %s\n",
801 				handled, csr,
802 				decode_ep0stage(musb->ep0_state));
803 
804 			/* unless we need to delegate this to the gadget
805 			 * driver, we know how to wrap this up:  csr0 has
806 			 * not yet been written.
807 			 */
808 			if (handled < 0)
809 				goto stall;
810 			else if (handled > 0)
811 				goto finish;
812 
813 			handled = forward_to_driver(musb, &setup);
814 			if (handled < 0) {
815 				musb_ep_select(mbase, 0);
816 stall:
817 				DBG(3, "stall (%d)\n", handled);
818 				musb->ackpend |= MUSB_CSR0_P_SENDSTALL;
819 				musb->ep0_state = MUSB_EP0_STAGE_IDLE;
820 finish:
821 				musb_writew(regs, MUSB_CSR0,
822 						musb->ackpend);
823 				musb->ackpend = 0;
824 			}
825 		}
826 		break;
827 
828 	case MUSB_EP0_STAGE_ACKWAIT:
829 		/* This should not happen. But happens with tusb6010 with
830 		 * g_file_storage and high speed. Do nothing.
831 		 */
832 		retval = IRQ_HANDLED;
833 		break;
834 
835 	default:
836 		/* "can't happen" */
837 		WARN_ON(1);
838 		musb_writew(regs, MUSB_CSR0, MUSB_CSR0_P_SENDSTALL);
839 		musb->ep0_state = MUSB_EP0_STAGE_IDLE;
840 		break;
841 	}
842 
843 	return retval;
844 }
845 
846 
847 static int
848 musb_g_ep0_enable(struct usb_ep *ep, const struct usb_endpoint_descriptor *desc)
849 {
850 	/* always enabled */
851 	return -EINVAL;
852 }
853 
854 static int musb_g_ep0_disable(struct usb_ep *e)
855 {
856 	/* always enabled */
857 	return -EINVAL;
858 }
859 
860 static int
861 musb_g_ep0_queue(struct usb_ep *e, struct usb_request *r, gfp_t gfp_flags)
862 {
863 	struct musb_ep		*ep;
864 	struct musb_request	*req;
865 	struct musb		*musb;
866 	int			status;
867 	unsigned long		lockflags;
868 	void __iomem		*regs;
869 
870 	if (!e || !r)
871 		return -EINVAL;
872 
873 	ep = to_musb_ep(e);
874 	musb = ep->musb;
875 	regs = musb->control_ep->regs;
876 
877 	req = to_musb_request(r);
878 	req->musb = musb;
879 	req->request.actual = 0;
880 	req->request.status = -EINPROGRESS;
881 	req->tx = ep->is_in;
882 
883 	spin_lock_irqsave(&musb->lock, lockflags);
884 
885 	if (!list_empty(&ep->req_list)) {
886 		status = -EBUSY;
887 		goto cleanup;
888 	}
889 
890 	switch (musb->ep0_state) {
891 	case MUSB_EP0_STAGE_RX:		/* control-OUT data */
892 	case MUSB_EP0_STAGE_TX:		/* control-IN data */
893 	case MUSB_EP0_STAGE_ACKWAIT:	/* zero-length data */
894 		status = 0;
895 		break;
896 	default:
897 		DBG(1, "ep0 request queued in state %d\n",
898 				musb->ep0_state);
899 		status = -EINVAL;
900 		goto cleanup;
901 	}
902 
903 	/* add request to the list */
904 	list_add_tail(&(req->request.list), &(ep->req_list));
905 
906 	DBG(3, "queue to %s (%s), length=%d\n",
907 			ep->name, ep->is_in ? "IN/TX" : "OUT/RX",
908 			req->request.length);
909 
910 	musb_ep_select(musb->mregs, 0);
911 
912 	/* sequence #1, IN ... start writing the data */
913 	if (musb->ep0_state == MUSB_EP0_STAGE_TX)
914 		ep0_txstate(musb);
915 
916 	/* sequence #3, no-data ... issue IN status */
917 	else if (musb->ep0_state == MUSB_EP0_STAGE_ACKWAIT) {
918 		if (req->request.length)
919 			status = -EINVAL;
920 		else {
921 			musb->ep0_state = MUSB_EP0_STAGE_STATUSIN;
922 			musb_writew(regs, MUSB_CSR0,
923 					musb->ackpend | MUSB_CSR0_P_DATAEND);
924 			musb->ackpend = 0;
925 			musb_g_ep0_giveback(ep->musb, r);
926 		}
927 
928 	/* else for sequence #2 (OUT), caller provides a buffer
929 	 * before the next packet arrives.  deferred responses
930 	 * (after SETUP is acked) are racey.
931 	 */
932 	} else if (musb->ackpend) {
933 		musb_writew(regs, MUSB_CSR0, musb->ackpend);
934 		musb->ackpend = 0;
935 	}
936 
937 cleanup:
938 	spin_unlock_irqrestore(&musb->lock, lockflags);
939 	return status;
940 }
941 
942 static int musb_g_ep0_dequeue(struct usb_ep *ep, struct usb_request *req)
943 {
944 	/* we just won't support this */
945 	return -EINVAL;
946 }
947 
948 static int musb_g_ep0_halt(struct usb_ep *e, int value)
949 {
950 	struct musb_ep		*ep;
951 	struct musb		*musb;
952 	void __iomem		*base, *regs;
953 	unsigned long		flags;
954 	int			status;
955 	u16			csr;
956 
957 	if (!e || !value)
958 		return -EINVAL;
959 
960 	ep = to_musb_ep(e);
961 	musb = ep->musb;
962 	base = musb->mregs;
963 	regs = musb->control_ep->regs;
964 	status = 0;
965 
966 	spin_lock_irqsave(&musb->lock, flags);
967 
968 	if (!list_empty(&ep->req_list)) {
969 		status = -EBUSY;
970 		goto cleanup;
971 	}
972 
973 	musb_ep_select(base, 0);
974 	csr = musb->ackpend;
975 
976 	switch (musb->ep0_state) {
977 
978 	/* Stalls are usually issued after parsing SETUP packet, either
979 	 * directly in irq context from setup() or else later.
980 	 */
981 	case MUSB_EP0_STAGE_TX:		/* control-IN data */
982 	case MUSB_EP0_STAGE_ACKWAIT:	/* STALL for zero-length data */
983 	case MUSB_EP0_STAGE_RX:		/* control-OUT data */
984 		csr = musb_readw(regs, MUSB_CSR0);
985 		/* FALLTHROUGH */
986 
987 	/* It's also OK to issue stalls during callbacks when a non-empty
988 	 * DATA stage buffer has been read (or even written).
989 	 */
990 	case MUSB_EP0_STAGE_STATUSIN:	/* control-OUT status */
991 	case MUSB_EP0_STAGE_STATUSOUT:	/* control-IN status */
992 
993 		csr |= MUSB_CSR0_P_SENDSTALL;
994 		musb_writew(regs, MUSB_CSR0, csr);
995 		musb->ep0_state = MUSB_EP0_STAGE_IDLE;
996 		musb->ackpend = 0;
997 		break;
998 	default:
999 		DBG(1, "ep0 can't halt in state %d\n", musb->ep0_state);
1000 		status = -EINVAL;
1001 	}
1002 
1003 cleanup:
1004 	spin_unlock_irqrestore(&musb->lock, flags);
1005 	return status;
1006 }
1007 
1008 const struct usb_ep_ops musb_g_ep0_ops = {
1009 	.enable		= musb_g_ep0_enable,
1010 	.disable	= musb_g_ep0_disable,
1011 	.alloc_request	= musb_alloc_request,
1012 	.free_request	= musb_free_request,
1013 	.queue		= musb_g_ep0_queue,
1014 	.dequeue	= musb_g_ep0_dequeue,
1015 	.set_halt	= musb_g_ep0_halt,
1016 };
1017