xref: /openbmc/linux/drivers/usb/dwc3/ep0.c (revision 7490ca1e)
1 /**
2  * ep0.c - DesignWare USB3 DRD Controller Endpoint 0 Handling
3  *
4  * Copyright (C) 2010-2011 Texas Instruments Incorporated - http://www.ti.com
5  *
6  * Authors: Felipe Balbi <balbi@ti.com>,
7  *	    Sebastian Andrzej Siewior <bigeasy@linutronix.de>
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions, and the following disclaimer,
14  *    without modification.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. The names of the above-listed copyright holders may not be used
19  *    to endorse or promote products derived from this software without
20  *    specific prior written permission.
21  *
22  * ALTERNATIVELY, this software may be distributed under the terms of the
23  * GNU General Public License ("GPL") version 2, as published by the Free
24  * Software Foundation.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
27  * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
28  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
30  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
31  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
32  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
33  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
34  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
35  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
36  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
37  */
38 
39 #include <linux/kernel.h>
40 #include <linux/slab.h>
41 #include <linux/spinlock.h>
42 #include <linux/platform_device.h>
43 #include <linux/pm_runtime.h>
44 #include <linux/interrupt.h>
45 #include <linux/io.h>
46 #include <linux/list.h>
47 #include <linux/dma-mapping.h>
48 
49 #include <linux/usb/ch9.h>
50 #include <linux/usb/gadget.h>
51 #include <linux/usb/composite.h>
52 
53 #include "core.h"
54 #include "gadget.h"
55 #include "io.h"
56 
57 static void dwc3_ep0_do_control_status(struct dwc3 *dwc, u32 epnum);
58 
59 static const char *dwc3_ep0_state_string(enum dwc3_ep0_state state)
60 {
61 	switch (state) {
62 	case EP0_UNCONNECTED:
63 		return "Unconnected";
64 	case EP0_SETUP_PHASE:
65 		return "Setup Phase";
66 	case EP0_DATA_PHASE:
67 		return "Data Phase";
68 	case EP0_STATUS_PHASE:
69 		return "Status Phase";
70 	default:
71 		return "UNKNOWN";
72 	}
73 }
74 
75 static int dwc3_ep0_start_trans(struct dwc3 *dwc, u8 epnum, dma_addr_t buf_dma,
76 		u32 len, u32 type)
77 {
78 	struct dwc3_gadget_ep_cmd_params params;
79 	struct dwc3_trb_hw		*trb_hw;
80 	struct dwc3_trb			trb;
81 	struct dwc3_ep			*dep;
82 
83 	int				ret;
84 
85 	dep = dwc->eps[epnum];
86 	if (dep->flags & DWC3_EP_BUSY) {
87 		dev_vdbg(dwc->dev, "%s: still busy\n", dep->name);
88 		return 0;
89 	}
90 
91 	trb_hw = dwc->ep0_trb;
92 	memset(&trb, 0, sizeof(trb));
93 
94 	trb.trbctl = type;
95 	trb.bplh = buf_dma;
96 	trb.length = len;
97 
98 	trb.hwo	= 1;
99 	trb.lst	= 1;
100 	trb.ioc	= 1;
101 	trb.isp_imi = 1;
102 
103 	dwc3_trb_to_hw(&trb, trb_hw);
104 
105 	memset(&params, 0, sizeof(params));
106 	params.param0 = upper_32_bits(dwc->ep0_trb_addr);
107 	params.param1 = lower_32_bits(dwc->ep0_trb_addr);
108 
109 	ret = dwc3_send_gadget_ep_cmd(dwc, dep->number,
110 			DWC3_DEPCMD_STARTTRANSFER, &params);
111 	if (ret < 0) {
112 		dev_dbg(dwc->dev, "failed to send STARTTRANSFER command\n");
113 		return ret;
114 	}
115 
116 	dep->flags |= DWC3_EP_BUSY;
117 	dep->res_trans_idx = dwc3_gadget_ep_get_transfer_index(dwc,
118 			dep->number);
119 
120 	dwc->ep0_next_event = DWC3_EP0_COMPLETE;
121 
122 	return 0;
123 }
124 
125 static int __dwc3_gadget_ep0_queue(struct dwc3_ep *dep,
126 		struct dwc3_request *req)
127 {
128 	struct dwc3		*dwc = dep->dwc;
129 	int			ret = 0;
130 
131 	req->request.actual	= 0;
132 	req->request.status	= -EINPROGRESS;
133 	req->epnum		= dep->number;
134 
135 	list_add_tail(&req->list, &dep->request_list);
136 
137 	/*
138 	 * Gadget driver might not be quick enough to queue a request
139 	 * before we get a Transfer Not Ready event on this endpoint.
140 	 *
141 	 * In that case, we will set DWC3_EP_PENDING_REQUEST. When that
142 	 * flag is set, it's telling us that as soon as Gadget queues the
143 	 * required request, we should kick the transfer here because the
144 	 * IRQ we were waiting for is long gone.
145 	 */
146 	if (dep->flags & DWC3_EP_PENDING_REQUEST) {
147 		unsigned	direction;
148 
149 		direction = !!(dep->flags & DWC3_EP0_DIR_IN);
150 
151 		if (dwc->ep0state != EP0_DATA_PHASE) {
152 			dev_WARN(dwc->dev, "Unexpected pending request\n");
153 			return 0;
154 		}
155 
156 		ret = dwc3_ep0_start_trans(dwc, direction,
157 				req->request.dma, req->request.length,
158 				DWC3_TRBCTL_CONTROL_DATA);
159 		dep->flags &= ~(DWC3_EP_PENDING_REQUEST |
160 				DWC3_EP0_DIR_IN);
161 	} else if (dwc->delayed_status) {
162 		dwc->delayed_status = false;
163 
164 		if (dwc->ep0state == EP0_STATUS_PHASE)
165 			dwc3_ep0_do_control_status(dwc, 1);
166 		else
167 			dev_dbg(dwc->dev, "too early for delayed status\n");
168 	}
169 
170 	return ret;
171 }
172 
173 int dwc3_gadget_ep0_queue(struct usb_ep *ep, struct usb_request *request,
174 		gfp_t gfp_flags)
175 {
176 	struct dwc3_request		*req = to_dwc3_request(request);
177 	struct dwc3_ep			*dep = to_dwc3_ep(ep);
178 	struct dwc3			*dwc = dep->dwc;
179 
180 	unsigned long			flags;
181 
182 	int				ret;
183 
184 	spin_lock_irqsave(&dwc->lock, flags);
185 	if (!dep->desc) {
186 		dev_dbg(dwc->dev, "trying to queue request %p to disabled %s\n",
187 				request, dep->name);
188 		ret = -ESHUTDOWN;
189 		goto out;
190 	}
191 
192 	/* we share one TRB for ep0/1 */
193 	if (!list_empty(&dep->request_list)) {
194 		ret = -EBUSY;
195 		goto out;
196 	}
197 
198 	dev_vdbg(dwc->dev, "queueing request %p to %s length %d, state '%s'\n",
199 			request, dep->name, request->length,
200 			dwc3_ep0_state_string(dwc->ep0state));
201 
202 	ret = __dwc3_gadget_ep0_queue(dep, req);
203 
204 out:
205 	spin_unlock_irqrestore(&dwc->lock, flags);
206 
207 	return ret;
208 }
209 
210 static void dwc3_ep0_stall_and_restart(struct dwc3 *dwc)
211 {
212 	struct dwc3_ep		*dep = dwc->eps[0];
213 
214 	/* stall is always issued on EP0 */
215 	__dwc3_gadget_ep_set_halt(dep, 1);
216 	dep->flags = DWC3_EP_ENABLED;
217 	dwc->delayed_status = false;
218 
219 	if (!list_empty(&dep->request_list)) {
220 		struct dwc3_request	*req;
221 
222 		req = next_request(&dep->request_list);
223 		dwc3_gadget_giveback(dep, req, -ECONNRESET);
224 	}
225 
226 	dwc->ep0state = EP0_SETUP_PHASE;
227 	dwc3_ep0_out_start(dwc);
228 }
229 
230 void dwc3_ep0_out_start(struct dwc3 *dwc)
231 {
232 	int				ret;
233 
234 	ret = dwc3_ep0_start_trans(dwc, 0, dwc->ctrl_req_addr, 8,
235 			DWC3_TRBCTL_CONTROL_SETUP);
236 	WARN_ON(ret < 0);
237 }
238 
239 static struct dwc3_ep *dwc3_wIndex_to_dep(struct dwc3 *dwc, __le16 wIndex_le)
240 {
241 	struct dwc3_ep		*dep;
242 	u32			windex = le16_to_cpu(wIndex_le);
243 	u32			epnum;
244 
245 	epnum = (windex & USB_ENDPOINT_NUMBER_MASK) << 1;
246 	if ((windex & USB_ENDPOINT_DIR_MASK) == USB_DIR_IN)
247 		epnum |= 1;
248 
249 	dep = dwc->eps[epnum];
250 	if (dep->flags & DWC3_EP_ENABLED)
251 		return dep;
252 
253 	return NULL;
254 }
255 
256 static void dwc3_ep0_status_cmpl(struct usb_ep *ep, struct usb_request *req)
257 {
258 }
259 /*
260  * ch 9.4.5
261  */
262 static int dwc3_ep0_handle_status(struct dwc3 *dwc,
263 		struct usb_ctrlrequest *ctrl)
264 {
265 	struct dwc3_ep		*dep;
266 	u32			recip;
267 	u16			usb_status = 0;
268 	__le16			*response_pkt;
269 
270 	recip = ctrl->bRequestType & USB_RECIP_MASK;
271 	switch (recip) {
272 	case USB_RECIP_DEVICE:
273 		/*
274 		 * We are self-powered. U1/U2/LTM will be set later
275 		 * once we handle this states. RemoteWakeup is 0 on SS
276 		 */
277 		usb_status |= dwc->is_selfpowered << USB_DEVICE_SELF_POWERED;
278 		break;
279 
280 	case USB_RECIP_INTERFACE:
281 		/*
282 		 * Function Remote Wake Capable	D0
283 		 * Function Remote Wakeup	D1
284 		 */
285 		break;
286 
287 	case USB_RECIP_ENDPOINT:
288 		dep = dwc3_wIndex_to_dep(dwc, ctrl->wIndex);
289 		if (!dep)
290 			return -EINVAL;
291 
292 		if (dep->flags & DWC3_EP_STALL)
293 			usb_status = 1 << USB_ENDPOINT_HALT;
294 		break;
295 	default:
296 		return -EINVAL;
297 	};
298 
299 	response_pkt = (__le16 *) dwc->setup_buf;
300 	*response_pkt = cpu_to_le16(usb_status);
301 
302 	dep = dwc->eps[0];
303 	dwc->ep0_usb_req.dep = dep;
304 	dwc->ep0_usb_req.request.length = sizeof(*response_pkt);
305 	dwc->ep0_usb_req.request.dma = dwc->setup_buf_addr;
306 	dwc->ep0_usb_req.request.complete = dwc3_ep0_status_cmpl;
307 
308 	return __dwc3_gadget_ep0_queue(dep, &dwc->ep0_usb_req);
309 }
310 
311 static int dwc3_ep0_handle_feature(struct dwc3 *dwc,
312 		struct usb_ctrlrequest *ctrl, int set)
313 {
314 	struct dwc3_ep		*dep;
315 	u32			recip;
316 	u32			wValue;
317 	u32			wIndex;
318 	u32			reg;
319 	int			ret;
320 	u32			mode;
321 
322 	wValue = le16_to_cpu(ctrl->wValue);
323 	wIndex = le16_to_cpu(ctrl->wIndex);
324 	recip = ctrl->bRequestType & USB_RECIP_MASK;
325 	switch (recip) {
326 	case USB_RECIP_DEVICE:
327 
328 		/*
329 		 * 9.4.1 says only only for SS, in AddressState only for
330 		 * default control pipe
331 		 */
332 		switch (wValue) {
333 		case USB_DEVICE_U1_ENABLE:
334 		case USB_DEVICE_U2_ENABLE:
335 		case USB_DEVICE_LTM_ENABLE:
336 			if (dwc->dev_state != DWC3_CONFIGURED_STATE)
337 				return -EINVAL;
338 			if (dwc->speed != DWC3_DSTS_SUPERSPEED)
339 				return -EINVAL;
340 		}
341 
342 		/* XXX add U[12] & LTM */
343 		switch (wValue) {
344 		case USB_DEVICE_REMOTE_WAKEUP:
345 			break;
346 		case USB_DEVICE_U1_ENABLE:
347 			break;
348 		case USB_DEVICE_U2_ENABLE:
349 			break;
350 		case USB_DEVICE_LTM_ENABLE:
351 			break;
352 
353 		case USB_DEVICE_TEST_MODE:
354 			if ((wIndex & 0xff) != 0)
355 				return -EINVAL;
356 			if (!set)
357 				return -EINVAL;
358 
359 			mode = wIndex >> 8;
360 			reg = dwc3_readl(dwc->regs, DWC3_DCTL);
361 			reg &= ~DWC3_DCTL_TSTCTRL_MASK;
362 
363 			switch (mode) {
364 			case TEST_J:
365 			case TEST_K:
366 			case TEST_SE0_NAK:
367 			case TEST_PACKET:
368 			case TEST_FORCE_EN:
369 				reg |= mode << 1;
370 				break;
371 			default:
372 				return -EINVAL;
373 			}
374 			dwc3_writel(dwc->regs, DWC3_DCTL, reg);
375 			break;
376 		default:
377 			return -EINVAL;
378 		}
379 		break;
380 
381 	case USB_RECIP_INTERFACE:
382 		switch (wValue) {
383 		case USB_INTRF_FUNC_SUSPEND:
384 			if (wIndex & USB_INTRF_FUNC_SUSPEND_LP)
385 				/* XXX enable Low power suspend */
386 				;
387 			if (wIndex & USB_INTRF_FUNC_SUSPEND_RW)
388 				/* XXX enable remote wakeup */
389 				;
390 			break;
391 		default:
392 			return -EINVAL;
393 		}
394 		break;
395 
396 	case USB_RECIP_ENDPOINT:
397 		switch (wValue) {
398 		case USB_ENDPOINT_HALT:
399 			dep =  dwc3_wIndex_to_dep(dwc, wIndex);
400 			if (!dep)
401 				return -EINVAL;
402 			ret = __dwc3_gadget_ep_set_halt(dep, set);
403 			if (ret)
404 				return -EINVAL;
405 			break;
406 		default:
407 			return -EINVAL;
408 		}
409 		break;
410 
411 	default:
412 		return -EINVAL;
413 	};
414 
415 	return 0;
416 }
417 
418 static int dwc3_ep0_set_address(struct dwc3 *dwc, struct usb_ctrlrequest *ctrl)
419 {
420 	u32 addr;
421 	u32 reg;
422 
423 	addr = le16_to_cpu(ctrl->wValue);
424 	if (addr > 127) {
425 		dev_dbg(dwc->dev, "invalid device address %d\n", addr);
426 		return -EINVAL;
427 	}
428 
429 	if (dwc->dev_state == DWC3_CONFIGURED_STATE) {
430 		dev_dbg(dwc->dev, "trying to set address when configured\n");
431 		return -EINVAL;
432 	}
433 
434 	reg = dwc3_readl(dwc->regs, DWC3_DCFG);
435 	reg &= ~(DWC3_DCFG_DEVADDR_MASK);
436 	reg |= DWC3_DCFG_DEVADDR(addr);
437 	dwc3_writel(dwc->regs, DWC3_DCFG, reg);
438 
439 	if (addr)
440 		dwc->dev_state = DWC3_ADDRESS_STATE;
441 	else
442 		dwc->dev_state = DWC3_DEFAULT_STATE;
443 
444 	return 0;
445 }
446 
447 static int dwc3_ep0_delegate_req(struct dwc3 *dwc, struct usb_ctrlrequest *ctrl)
448 {
449 	int ret;
450 
451 	spin_unlock(&dwc->lock);
452 	ret = dwc->gadget_driver->setup(&dwc->gadget, ctrl);
453 	spin_lock(&dwc->lock);
454 	return ret;
455 }
456 
457 static int dwc3_ep0_set_config(struct dwc3 *dwc, struct usb_ctrlrequest *ctrl)
458 {
459 	u32 cfg;
460 	int ret;
461 
462 	dwc->start_config_issued = false;
463 	cfg = le16_to_cpu(ctrl->wValue);
464 
465 	switch (dwc->dev_state) {
466 	case DWC3_DEFAULT_STATE:
467 		return -EINVAL;
468 		break;
469 
470 	case DWC3_ADDRESS_STATE:
471 		ret = dwc3_ep0_delegate_req(dwc, ctrl);
472 		/* if the cfg matches and the cfg is non zero */
473 		if (!ret && cfg)
474 			dwc->dev_state = DWC3_CONFIGURED_STATE;
475 		break;
476 
477 	case DWC3_CONFIGURED_STATE:
478 		ret = dwc3_ep0_delegate_req(dwc, ctrl);
479 		if (!cfg)
480 			dwc->dev_state = DWC3_ADDRESS_STATE;
481 		break;
482 	default:
483 		ret = -EINVAL;
484 	}
485 	return ret;
486 }
487 
488 static int dwc3_ep0_std_request(struct dwc3 *dwc, struct usb_ctrlrequest *ctrl)
489 {
490 	int ret;
491 
492 	switch (ctrl->bRequest) {
493 	case USB_REQ_GET_STATUS:
494 		dev_vdbg(dwc->dev, "USB_REQ_GET_STATUS\n");
495 		ret = dwc3_ep0_handle_status(dwc, ctrl);
496 		break;
497 	case USB_REQ_CLEAR_FEATURE:
498 		dev_vdbg(dwc->dev, "USB_REQ_CLEAR_FEATURE\n");
499 		ret = dwc3_ep0_handle_feature(dwc, ctrl, 0);
500 		break;
501 	case USB_REQ_SET_FEATURE:
502 		dev_vdbg(dwc->dev, "USB_REQ_SET_FEATURE\n");
503 		ret = dwc3_ep0_handle_feature(dwc, ctrl, 1);
504 		break;
505 	case USB_REQ_SET_ADDRESS:
506 		dev_vdbg(dwc->dev, "USB_REQ_SET_ADDRESS\n");
507 		ret = dwc3_ep0_set_address(dwc, ctrl);
508 		break;
509 	case USB_REQ_SET_CONFIGURATION:
510 		dev_vdbg(dwc->dev, "USB_REQ_SET_CONFIGURATION\n");
511 		ret = dwc3_ep0_set_config(dwc, ctrl);
512 		break;
513 	default:
514 		dev_vdbg(dwc->dev, "Forwarding to gadget driver\n");
515 		ret = dwc3_ep0_delegate_req(dwc, ctrl);
516 		break;
517 	};
518 
519 	return ret;
520 }
521 
522 static void dwc3_ep0_inspect_setup(struct dwc3 *dwc,
523 		const struct dwc3_event_depevt *event)
524 {
525 	struct usb_ctrlrequest *ctrl = dwc->ctrl_req;
526 	int ret;
527 	u32 len;
528 
529 	if (!dwc->gadget_driver)
530 		goto err;
531 
532 	len = le16_to_cpu(ctrl->wLength);
533 	if (!len) {
534 		dwc->three_stage_setup = false;
535 		dwc->ep0_expect_in = false;
536 		dwc->ep0_next_event = DWC3_EP0_NRDY_STATUS;
537 	} else {
538 		dwc->three_stage_setup = true;
539 		dwc->ep0_expect_in = !!(ctrl->bRequestType & USB_DIR_IN);
540 		dwc->ep0_next_event = DWC3_EP0_NRDY_DATA;
541 	}
542 
543 	if ((ctrl->bRequestType & USB_TYPE_MASK) == USB_TYPE_STANDARD)
544 		ret = dwc3_ep0_std_request(dwc, ctrl);
545 	else
546 		ret = dwc3_ep0_delegate_req(dwc, ctrl);
547 
548 	if (ret == USB_GADGET_DELAYED_STATUS)
549 		dwc->delayed_status = true;
550 
551 	if (ret >= 0)
552 		return;
553 
554 err:
555 	dwc3_ep0_stall_and_restart(dwc);
556 }
557 
558 static void dwc3_ep0_complete_data(struct dwc3 *dwc,
559 		const struct dwc3_event_depevt *event)
560 {
561 	struct dwc3_request	*r = NULL;
562 	struct usb_request	*ur;
563 	struct dwc3_trb		trb;
564 	struct dwc3_ep		*ep0;
565 	u32			transferred;
566 	u8			epnum;
567 
568 	epnum = event->endpoint_number;
569 	ep0 = dwc->eps[0];
570 
571 	dwc->ep0_next_event = DWC3_EP0_NRDY_STATUS;
572 
573 	r = next_request(&ep0->request_list);
574 	ur = &r->request;
575 
576 	dwc3_trb_to_nat(dwc->ep0_trb, &trb);
577 
578 	if (dwc->ep0_bounced) {
579 
580 		transferred = min_t(u32, ur->length,
581 				ep0->endpoint.maxpacket - trb.length);
582 		memcpy(ur->buf, dwc->ep0_bounce, transferred);
583 		dwc->ep0_bounced = false;
584 	} else {
585 		transferred = ur->length - trb.length;
586 		ur->actual += transferred;
587 	}
588 
589 	if ((epnum & 1) && ur->actual < ur->length) {
590 		/* for some reason we did not get everything out */
591 
592 		dwc3_ep0_stall_and_restart(dwc);
593 	} else {
594 		/*
595 		 * handle the case where we have to send a zero packet. This
596 		 * seems to be case when req.length > maxpacket. Could it be?
597 		 */
598 		if (r)
599 			dwc3_gadget_giveback(ep0, r, 0);
600 	}
601 }
602 
603 static void dwc3_ep0_complete_req(struct dwc3 *dwc,
604 		const struct dwc3_event_depevt *event)
605 {
606 	struct dwc3_request	*r;
607 	struct dwc3_ep		*dep;
608 
609 	dep = dwc->eps[0];
610 
611 	if (!list_empty(&dep->request_list)) {
612 		r = next_request(&dep->request_list);
613 
614 		dwc3_gadget_giveback(dep, r, 0);
615 	}
616 
617 	dwc->ep0state = EP0_SETUP_PHASE;
618 	dwc3_ep0_out_start(dwc);
619 }
620 
621 static void dwc3_ep0_xfer_complete(struct dwc3 *dwc,
622 			const struct dwc3_event_depevt *event)
623 {
624 	struct dwc3_ep		*dep = dwc->eps[event->endpoint_number];
625 
626 	dep->flags &= ~DWC3_EP_BUSY;
627 	dwc->setup_packet_pending = false;
628 
629 	switch (dwc->ep0state) {
630 	case EP0_SETUP_PHASE:
631 		dev_vdbg(dwc->dev, "Inspecting Setup Bytes\n");
632 		dwc3_ep0_inspect_setup(dwc, event);
633 		break;
634 
635 	case EP0_DATA_PHASE:
636 		dev_vdbg(dwc->dev, "Data Phase\n");
637 		dwc3_ep0_complete_data(dwc, event);
638 		break;
639 
640 	case EP0_STATUS_PHASE:
641 		dev_vdbg(dwc->dev, "Status Phase\n");
642 		dwc3_ep0_complete_req(dwc, event);
643 		break;
644 	default:
645 		WARN(true, "UNKNOWN ep0state %d\n", dwc->ep0state);
646 	}
647 }
648 
649 static void dwc3_ep0_do_control_setup(struct dwc3 *dwc,
650 		const struct dwc3_event_depevt *event)
651 {
652 	dwc3_ep0_out_start(dwc);
653 }
654 
655 static void dwc3_ep0_do_control_data(struct dwc3 *dwc,
656 		const struct dwc3_event_depevt *event)
657 {
658 	struct dwc3_ep		*dep;
659 	struct dwc3_request	*req;
660 	int			ret;
661 
662 	dep = dwc->eps[0];
663 
664 	if (list_empty(&dep->request_list)) {
665 		dev_vdbg(dwc->dev, "pending request for EP0 Data phase\n");
666 		dep->flags |= DWC3_EP_PENDING_REQUEST;
667 
668 		if (event->endpoint_number)
669 			dep->flags |= DWC3_EP0_DIR_IN;
670 		return;
671 	}
672 
673 	req = next_request(&dep->request_list);
674 	req->direction = !!event->endpoint_number;
675 
676 	if (req->request.length == 0) {
677 		ret = dwc3_ep0_start_trans(dwc, event->endpoint_number,
678 				dwc->ctrl_req_addr, 0,
679 				DWC3_TRBCTL_CONTROL_DATA);
680 	} else if ((req->request.length % dep->endpoint.maxpacket)
681 			&& (event->endpoint_number == 0)) {
682 		dwc3_map_buffer_to_dma(req);
683 
684 		WARN_ON(req->request.length > dep->endpoint.maxpacket);
685 
686 		dwc->ep0_bounced = true;
687 
688 		/*
689 		 * REVISIT in case request length is bigger than EP0
690 		 * wMaxPacketSize, we will need two chained TRBs to handle
691 		 * the transfer.
692 		 */
693 		ret = dwc3_ep0_start_trans(dwc, event->endpoint_number,
694 				dwc->ep0_bounce_addr, dep->endpoint.maxpacket,
695 				DWC3_TRBCTL_CONTROL_DATA);
696 	} else {
697 		dwc3_map_buffer_to_dma(req);
698 
699 		ret = dwc3_ep0_start_trans(dwc, event->endpoint_number,
700 				req->request.dma, req->request.length,
701 				DWC3_TRBCTL_CONTROL_DATA);
702 	}
703 
704 	WARN_ON(ret < 0);
705 }
706 
707 static int dwc3_ep0_start_control_status(struct dwc3_ep *dep)
708 {
709 	struct dwc3		*dwc = dep->dwc;
710 	u32			type;
711 
712 	type = dwc->three_stage_setup ? DWC3_TRBCTL_CONTROL_STATUS3
713 		: DWC3_TRBCTL_CONTROL_STATUS2;
714 
715 	return dwc3_ep0_start_trans(dwc, dep->number,
716 			dwc->ctrl_req_addr, 0, type);
717 }
718 
719 static void dwc3_ep0_do_control_status(struct dwc3 *dwc, u32 epnum)
720 {
721 	struct dwc3_ep		*dep = dwc->eps[epnum];
722 
723 	WARN_ON(dwc3_ep0_start_control_status(dep));
724 }
725 
726 static void dwc3_ep0_xfernotready(struct dwc3 *dwc,
727 		const struct dwc3_event_depevt *event)
728 {
729 	dwc->setup_packet_pending = true;
730 
731 	/*
732 	 * This part is very tricky: If we has just handled
733 	 * XferNotReady(Setup) and we're now expecting a
734 	 * XferComplete but, instead, we receive another
735 	 * XferNotReady(Setup), we should STALL and restart
736 	 * the state machine.
737 	 *
738 	 * In all other cases, we just continue waiting
739 	 * for the XferComplete event.
740 	 *
741 	 * We are a little bit unsafe here because we're
742 	 * not trying to ensure that last event was, indeed,
743 	 * XferNotReady(Setup).
744 	 *
745 	 * Still, we don't expect any condition where that
746 	 * should happen and, even if it does, it would be
747 	 * another error condition.
748 	 */
749 	if (dwc->ep0_next_event == DWC3_EP0_COMPLETE) {
750 		switch (event->status) {
751 		case DEPEVT_STATUS_CONTROL_SETUP:
752 			dev_vdbg(dwc->dev, "Unexpected XferNotReady(Setup)\n");
753 			dwc3_ep0_stall_and_restart(dwc);
754 			break;
755 		case DEPEVT_STATUS_CONTROL_DATA:
756 			/* FALLTHROUGH */
757 		case DEPEVT_STATUS_CONTROL_STATUS:
758 			/* FALLTHROUGH */
759 		default:
760 			dev_vdbg(dwc->dev, "waiting for XferComplete\n");
761 		}
762 
763 		return;
764 	}
765 
766 	switch (event->status) {
767 	case DEPEVT_STATUS_CONTROL_SETUP:
768 		dev_vdbg(dwc->dev, "Control Setup\n");
769 
770 		dwc->ep0state = EP0_SETUP_PHASE;
771 
772 		dwc3_ep0_do_control_setup(dwc, event);
773 		break;
774 
775 	case DEPEVT_STATUS_CONTROL_DATA:
776 		dev_vdbg(dwc->dev, "Control Data\n");
777 
778 		dwc->ep0state = EP0_DATA_PHASE;
779 
780 		if (dwc->ep0_next_event != DWC3_EP0_NRDY_DATA) {
781 			dev_vdbg(dwc->dev, "Expected %d got %d\n",
782 					dwc->ep0_next_event,
783 					DWC3_EP0_NRDY_DATA);
784 
785 			dwc3_ep0_stall_and_restart(dwc);
786 			return;
787 		}
788 
789 		/*
790 		 * One of the possible error cases is when Host _does_
791 		 * request for Data Phase, but it does so on the wrong
792 		 * direction.
793 		 *
794 		 * Here, we already know ep0_next_event is DATA (see above),
795 		 * so we only need to check for direction.
796 		 */
797 		if (dwc->ep0_expect_in != event->endpoint_number) {
798 			dev_vdbg(dwc->dev, "Wrong direction for Data phase\n");
799 			dwc3_ep0_stall_and_restart(dwc);
800 			return;
801 		}
802 
803 		dwc3_ep0_do_control_data(dwc, event);
804 		break;
805 
806 	case DEPEVT_STATUS_CONTROL_STATUS:
807 		dev_vdbg(dwc->dev, "Control Status\n");
808 
809 		dwc->ep0state = EP0_STATUS_PHASE;
810 
811 		if (dwc->ep0_next_event != DWC3_EP0_NRDY_STATUS) {
812 			dev_vdbg(dwc->dev, "Expected %d got %d\n",
813 					dwc->ep0_next_event,
814 					DWC3_EP0_NRDY_STATUS);
815 
816 			dwc3_ep0_stall_and_restart(dwc);
817 			return;
818 		}
819 
820 		if (dwc->delayed_status) {
821 			WARN_ON_ONCE(event->endpoint_number != 1);
822 			dev_vdbg(dwc->dev, "Mass Storage delayed status\n");
823 			return;
824 		}
825 
826 		dwc3_ep0_do_control_status(dwc, event->endpoint_number);
827 	}
828 }
829 
830 void dwc3_ep0_interrupt(struct dwc3 *dwc,
831 		const struct dwc3_event_depevt *event)
832 {
833 	u8			epnum = event->endpoint_number;
834 
835 	dev_dbg(dwc->dev, "%s while ep%d%s in state '%s'\n",
836 			dwc3_ep_event_string(event->endpoint_event),
837 			epnum >> 1, (epnum & 1) ? "in" : "out",
838 			dwc3_ep0_state_string(dwc->ep0state));
839 
840 	switch (event->endpoint_event) {
841 	case DWC3_DEPEVT_XFERCOMPLETE:
842 		dwc3_ep0_xfer_complete(dwc, event);
843 		break;
844 
845 	case DWC3_DEPEVT_XFERNOTREADY:
846 		dwc3_ep0_xfernotready(dwc, event);
847 		break;
848 
849 	case DWC3_DEPEVT_XFERINPROGRESS:
850 	case DWC3_DEPEVT_RXTXFIFOEVT:
851 	case DWC3_DEPEVT_STREAMEVT:
852 	case DWC3_DEPEVT_EPCMDCMPLT:
853 		break;
854 	}
855 }
856