xref: /linux/drivers/usb/musb/musb_host.c (revision 60684c2bd35064043360e6f716d1b7c20e967b7d)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * MUSB OTG driver host support
4  *
5  * Copyright 2005 Mentor Graphics Corporation
6  * Copyright (C) 2005-2006 by Texas Instruments
7  * Copyright (C) 2006-2007 Nokia Corporation
8  * Copyright (C) 2008-2009 MontaVista Software, Inc. <source@mvista.com>
9  */
10 
11 #include <linux/module.h>
12 #include <linux/kernel.h>
13 #include <linux/delay.h>
14 #include <linux/sched.h>
15 #include <linux/slab.h>
16 #include <linux/errno.h>
17 #include <linux/list.h>
18 #include <linux/dma-mapping.h>
19 
20 #include "musb_core.h"
21 #include "musb_host.h"
22 #include "musb_trace.h"
23 
24 /* MUSB HOST status 22-mar-2006
25  *
26  * - There's still lots of partial code duplication for fault paths, so
27  *   they aren't handled as consistently as they need to be.
28  *
29  * - PIO mostly behaved when last tested.
30  *     + including ep0, with all usbtest cases 9, 10
31  *     + usbtest 14 (ep0out) doesn't seem to run at all
32  *     + double buffered OUT/TX endpoints saw stalls(!) with certain usbtest
33  *       configurations, but otherwise double buffering passes basic tests.
34  *     + for 2.6.N, for N > ~10, needs API changes for hcd framework.
35  *
36  * - DMA (CPPI) ... partially behaves, not currently recommended
37  *     + about 1/15 the speed of typical EHCI implementations (PCI)
38  *     + RX, all too often reqpkt seems to misbehave after tx
39  *     + TX, no known issues (other than evident silicon issue)
40  *
41  * - DMA (Mentor/OMAP) ...has at least toggle update problems
42  *
43  * - [23-feb-2009] minimal traffic scheduling to avoid bulk RX packet
44  *   starvation ... nothing yet for TX, interrupt, or bulk.
45  *
46  * - Not tested with HNP, but some SRP paths seem to behave.
47  *
48  * NOTE 24-August-2006:
49  *
50  * - Bulk traffic finally uses both sides of hardware ep1, freeing up an
51  *   extra endpoint for periodic use enabling hub + keybd + mouse.  That
52  *   mostly works, except that with "usbnet" it's easy to trigger cases
53  *   with "ping" where RX loses.  (a) ping to davinci, even "ping -f",
54  *   fine; but (b) ping _from_ davinci, even "ping -c 1", ICMP RX loses
55  *   although ARP RX wins.  (That test was done with a full speed link.)
56  */
57 
58 
59 /*
60  * NOTE on endpoint usage:
61  *
62  * CONTROL transfers all go through ep0.  BULK ones go through dedicated IN
63  * and OUT endpoints ... hardware is dedicated for those "async" queue(s).
64  * (Yes, bulk _could_ use more of the endpoints than that, and would even
65  * benefit from it.)
66  *
67  * INTERUPPT and ISOCHRONOUS transfers are scheduled to the other endpoints.
68  * So far that scheduling is both dumb and optimistic:  the endpoint will be
69  * "claimed" until its software queue is no longer refilled.  No multiplexing
70  * of transfers between endpoints, or anything clever.
71  */
72 
73 struct musb *hcd_to_musb(struct usb_hcd *hcd)
74 {
75 	return *(struct musb **) hcd->hcd_priv;
76 }
77 
78 
79 static void musb_ep_program(struct musb *musb, u8 epnum,
80 			struct urb *urb, int is_out,
81 			u8 *buf, u32 offset, u32 len);
82 
83 /*
84  * Clear TX fifo. Needed to avoid BABBLE errors.
85  */
86 static void musb_h_tx_flush_fifo(struct musb_hw_ep *ep)
87 {
88 	struct musb	*musb = ep->musb;
89 	void __iomem	*epio = ep->regs;
90 	u16		csr;
91 	int		retries = 1000;
92 
93 	csr = musb_readw(epio, MUSB_TXCSR);
94 	while (csr & MUSB_TXCSR_FIFONOTEMPTY) {
95 		csr |= MUSB_TXCSR_FLUSHFIFO | MUSB_TXCSR_TXPKTRDY;
96 		musb_writew(epio, MUSB_TXCSR, csr);
97 		csr = musb_readw(epio, MUSB_TXCSR);
98 
99 		/*
100 		 * FIXME: sometimes the tx fifo flush failed, it has been
101 		 * observed during device disconnect on AM335x.
102 		 *
103 		 * To reproduce the issue, ensure tx urb(s) are queued when
104 		 * unplug the usb device which is connected to AM335x usb
105 		 * host port.
106 		 *
107 		 * I found using a usb-ethernet device and running iperf
108 		 * (client on AM335x) has very high chance to trigger it.
109 		 *
110 		 * Better to turn on musb_dbg() in musb_cleanup_urb() with
111 		 * CPPI enabled to see the issue when aborting the tx channel.
112 		 */
113 		if (dev_WARN_ONCE(musb->controller, retries-- < 1,
114 				"Could not flush host TX%d fifo: csr: %04x\n",
115 				ep->epnum, csr))
116 			return;
117 		mdelay(1);
118 	}
119 }
120 
121 static void musb_h_ep0_flush_fifo(struct musb_hw_ep *ep)
122 {
123 	void __iomem	*epio = ep->regs;
124 	u16		csr;
125 	int		retries = 5;
126 
127 	/* scrub any data left in the fifo */
128 	do {
129 		csr = musb_readw(epio, MUSB_TXCSR);
130 		if (!(csr & (MUSB_CSR0_TXPKTRDY | MUSB_CSR0_RXPKTRDY)))
131 			break;
132 		musb_writew(epio, MUSB_TXCSR, MUSB_CSR0_FLUSHFIFO);
133 		csr = musb_readw(epio, MUSB_TXCSR);
134 		udelay(10);
135 	} while (--retries);
136 
137 	WARN(!retries, "Could not flush host TX%d fifo: csr: %04x\n",
138 			ep->epnum, csr);
139 
140 	/* and reset for the next transfer */
141 	musb_writew(epio, MUSB_TXCSR, 0);
142 }
143 
144 /*
145  * Start transmit. Caller is responsible for locking shared resources.
146  * musb must be locked.
147  */
148 static inline void musb_h_tx_start(struct musb_hw_ep *ep)
149 {
150 	u16	txcsr;
151 
152 	/* NOTE: no locks here; caller should lock and select EP */
153 	if (ep->epnum) {
154 		txcsr = musb_readw(ep->regs, MUSB_TXCSR);
155 		txcsr |= MUSB_TXCSR_TXPKTRDY | MUSB_TXCSR_H_WZC_BITS;
156 		musb_writew(ep->regs, MUSB_TXCSR, txcsr);
157 	} else {
158 		txcsr = MUSB_CSR0_H_SETUPPKT | MUSB_CSR0_TXPKTRDY;
159 		musb_writew(ep->regs, MUSB_CSR0, txcsr);
160 	}
161 
162 }
163 
164 static inline void musb_h_tx_dma_start(struct musb_hw_ep *ep)
165 {
166 	u16	txcsr;
167 
168 	/* NOTE: no locks here; caller should lock and select EP */
169 	txcsr = musb_readw(ep->regs, MUSB_TXCSR);
170 	txcsr |= MUSB_TXCSR_DMAENAB | MUSB_TXCSR_H_WZC_BITS;
171 	if (is_cppi_enabled(ep->musb))
172 		txcsr |= MUSB_TXCSR_DMAMODE;
173 	musb_writew(ep->regs, MUSB_TXCSR, txcsr);
174 }
175 
176 static void musb_ep_set_qh(struct musb_hw_ep *ep, int is_in, struct musb_qh *qh)
177 {
178 	if (is_in != 0 || ep->is_shared_fifo)
179 		ep->in_qh  = qh;
180 	if (is_in == 0 || ep->is_shared_fifo)
181 		ep->out_qh = qh;
182 }
183 
184 static struct musb_qh *musb_ep_get_qh(struct musb_hw_ep *ep, int is_in)
185 {
186 	return is_in ? ep->in_qh : ep->out_qh;
187 }
188 
189 /*
190  * Start the URB at the front of an endpoint's queue
191  * end must be claimed from the caller.
192  *
193  * Context: controller locked, irqs blocked
194  */
195 static void
196 musb_start_urb(struct musb *musb, int is_in, struct musb_qh *qh)
197 {
198 	u32			len;
199 	void __iomem		*mbase =  musb->mregs;
200 	struct urb		*urb = next_urb(qh);
201 	void			*buf = urb->transfer_buffer;
202 	u32			offset = 0;
203 	struct musb_hw_ep	*hw_ep = qh->hw_ep;
204 	int			epnum = hw_ep->epnum;
205 
206 	/* initialize software qh state */
207 	qh->offset = 0;
208 	qh->segsize = 0;
209 
210 	/* gather right source of data */
211 	switch (qh->type) {
212 	case USB_ENDPOINT_XFER_CONTROL:
213 		/* control transfers always start with SETUP */
214 		is_in = 0;
215 		musb->ep0_stage = MUSB_EP0_START;
216 		buf = urb->setup_packet;
217 		len = 8;
218 		break;
219 	case USB_ENDPOINT_XFER_ISOC:
220 		qh->iso_idx = 0;
221 		qh->frame = 0;
222 		offset = urb->iso_frame_desc[0].offset;
223 		len = urb->iso_frame_desc[0].length;
224 		break;
225 	default:		/* bulk, interrupt */
226 		/* actual_length may be nonzero on retry paths */
227 		buf = urb->transfer_buffer + urb->actual_length;
228 		len = urb->transfer_buffer_length - urb->actual_length;
229 	}
230 
231 	trace_musb_urb_start(musb, urb);
232 
233 	/* Configure endpoint */
234 	musb_ep_set_qh(hw_ep, is_in, qh);
235 	musb_ep_program(musb, epnum, urb, !is_in, buf, offset, len);
236 
237 	/* transmit may have more work: start it when it is time */
238 	if (is_in)
239 		return;
240 
241 	/* determine if the time is right for a periodic transfer */
242 	switch (qh->type) {
243 	case USB_ENDPOINT_XFER_ISOC:
244 	case USB_ENDPOINT_XFER_INT:
245 		musb_dbg(musb, "check whether there's still time for periodic Tx");
246 		/* FIXME this doesn't implement that scheduling policy ...
247 		 * or handle framecounter wrapping
248 		 */
249 		if (1) {	/* Always assume URB_ISO_ASAP */
250 			/* REVISIT the SOF irq handler shouldn't duplicate
251 			 * this code; and we don't init urb->start_frame...
252 			 */
253 			qh->frame = 0;
254 			goto start;
255 		} else {
256 			qh->frame = urb->start_frame;
257 			/* enable SOF interrupt so we can count down */
258 			musb_dbg(musb, "SOF for %d", epnum);
259 #if 1 /* ifndef	CONFIG_ARCH_DAVINCI */
260 			musb_writeb(mbase, MUSB_INTRUSBE, 0xff);
261 #endif
262 		}
263 		break;
264 	default:
265 start:
266 		musb_dbg(musb, "Start TX%d %s", epnum,
267 			hw_ep->tx_channel ? "dma" : "pio");
268 
269 		if (!hw_ep->tx_channel)
270 			musb_h_tx_start(hw_ep);
271 		else if (is_cppi_enabled(musb) || tusb_dma_omap(musb))
272 			musb_h_tx_dma_start(hw_ep);
273 	}
274 }
275 
276 /* Context: caller owns controller lock, IRQs are blocked */
277 static void musb_giveback(struct musb *musb, struct urb *urb, int status)
278 __releases(musb->lock)
279 __acquires(musb->lock)
280 {
281 	trace_musb_urb_gb(musb, urb);
282 
283 	usb_hcd_unlink_urb_from_ep(musb->hcd, urb);
284 	spin_unlock(&musb->lock);
285 	usb_hcd_giveback_urb(musb->hcd, urb, status);
286 	spin_lock(&musb->lock);
287 }
288 
289 /*
290  * Advance this hardware endpoint's queue, completing the specified URB and
291  * advancing to either the next URB queued to that qh, or else invalidating
292  * that qh and advancing to the next qh scheduled after the current one.
293  *
294  * Context: caller owns controller lock, IRQs are blocked
295  */
296 static void musb_advance_schedule(struct musb *musb, struct urb *urb,
297 				  struct musb_hw_ep *hw_ep, int is_in)
298 {
299 	struct musb_qh		*qh = musb_ep_get_qh(hw_ep, is_in);
300 	struct musb_hw_ep	*ep = qh->hw_ep;
301 	int			ready = qh->is_ready;
302 	int			status;
303 	u16			toggle;
304 
305 	status = (urb->status == -EINPROGRESS) ? 0 : urb->status;
306 
307 	/* save toggle eagerly, for paranoia */
308 	switch (qh->type) {
309 	case USB_ENDPOINT_XFER_BULK:
310 	case USB_ENDPOINT_XFER_INT:
311 		toggle = musb->io.get_toggle(qh, !is_in);
312 		usb_settoggle(urb->dev, qh->epnum, !is_in, toggle ? 1 : 0);
313 		break;
314 	case USB_ENDPOINT_XFER_ISOC:
315 		if (status == 0 && urb->error_count)
316 			status = -EXDEV;
317 		break;
318 	}
319 
320 	qh->is_ready = 0;
321 	musb_giveback(musb, urb, status);
322 	qh->is_ready = ready;
323 
324 	/* reclaim resources (and bandwidth) ASAP; deschedule it, and
325 	 * invalidate qh as soon as list_empty(&hep->urb_list)
326 	 */
327 	if (list_empty(&qh->hep->urb_list)) {
328 		struct list_head	*head;
329 		struct dma_controller	*dma = musb->dma_controller;
330 
331 		if (is_in) {
332 			ep->rx_reinit = 1;
333 			if (ep->rx_channel) {
334 				dma->channel_release(ep->rx_channel);
335 				ep->rx_channel = NULL;
336 			}
337 		} else {
338 			ep->tx_reinit = 1;
339 			if (ep->tx_channel) {
340 				dma->channel_release(ep->tx_channel);
341 				ep->tx_channel = NULL;
342 			}
343 		}
344 
345 		/* Clobber old pointers to this qh */
346 		musb_ep_set_qh(ep, is_in, NULL);
347 		qh->hep->hcpriv = NULL;
348 
349 		switch (qh->type) {
350 
351 		case USB_ENDPOINT_XFER_CONTROL:
352 		case USB_ENDPOINT_XFER_BULK:
353 			/* fifo policy for these lists, except that NAKing
354 			 * should rotate a qh to the end (for fairness).
355 			 */
356 			if (qh->mux == 1) {
357 				head = qh->ring.prev;
358 				list_del(&qh->ring);
359 				kfree(qh);
360 				qh = first_qh(head);
361 				break;
362 			}
363 			fallthrough;
364 
365 		case USB_ENDPOINT_XFER_ISOC:
366 		case USB_ENDPOINT_XFER_INT:
367 			/* this is where periodic bandwidth should be
368 			 * de-allocated if it's tracked and allocated;
369 			 * and where we'd update the schedule tree...
370 			 */
371 			kfree(qh);
372 			qh = NULL;
373 			break;
374 		}
375 	}
376 
377 	if (qh != NULL && qh->is_ready) {
378 		musb_dbg(musb, "... next ep%d %cX urb %p",
379 		    hw_ep->epnum, is_in ? 'R' : 'T', next_urb(qh));
380 		musb_start_urb(musb, is_in, qh);
381 	}
382 }
383 
384 static u16 musb_h_flush_rxfifo(struct musb_hw_ep *hw_ep, u16 csr)
385 {
386 	/* we don't want fifo to fill itself again;
387 	 * ignore dma (various models),
388 	 * leave toggle alone (may not have been saved yet)
389 	 */
390 	csr |= MUSB_RXCSR_FLUSHFIFO | MUSB_RXCSR_RXPKTRDY;
391 	csr &= ~(MUSB_RXCSR_H_REQPKT
392 		| MUSB_RXCSR_H_AUTOREQ
393 		| MUSB_RXCSR_AUTOCLEAR);
394 
395 	/* write 2x to allow double buffering */
396 	musb_writew(hw_ep->regs, MUSB_RXCSR, csr);
397 	musb_writew(hw_ep->regs, MUSB_RXCSR, csr);
398 
399 	/* flush writebuffer */
400 	return musb_readw(hw_ep->regs, MUSB_RXCSR);
401 }
402 
403 /*
404  * PIO RX for a packet (or part of it).
405  */
406 static bool
407 musb_host_packet_rx(struct musb *musb, struct urb *urb, u8 epnum, u8 iso_err)
408 {
409 	u16			rx_count;
410 	u8			*buf;
411 	u16			csr;
412 	bool			done = false;
413 	u32			length;
414 	int			do_flush = 0;
415 	struct musb_hw_ep	*hw_ep = musb->endpoints + epnum;
416 	void __iomem		*epio = hw_ep->regs;
417 	struct musb_qh		*qh = hw_ep->in_qh;
418 	int			pipe = urb->pipe;
419 	void			*buffer = urb->transfer_buffer;
420 
421 	/* musb_ep_select(mbase, epnum); */
422 	rx_count = musb_readw(epio, MUSB_RXCOUNT);
423 	musb_dbg(musb, "RX%d count %d, buffer %p len %d/%d", epnum, rx_count,
424 			urb->transfer_buffer, qh->offset,
425 			urb->transfer_buffer_length);
426 
427 	/* unload FIFO */
428 	if (usb_pipeisoc(pipe)) {
429 		int					status = 0;
430 		struct usb_iso_packet_descriptor	*d;
431 
432 		if (iso_err) {
433 			status = -EILSEQ;
434 			urb->error_count++;
435 		}
436 
437 		d = urb->iso_frame_desc + qh->iso_idx;
438 		buf = buffer + d->offset;
439 		length = d->length;
440 		if (rx_count > length) {
441 			if (status == 0) {
442 				status = -EOVERFLOW;
443 				urb->error_count++;
444 			}
445 			musb_dbg(musb, "OVERFLOW %d into %d", rx_count, length);
446 			do_flush = 1;
447 		} else
448 			length = rx_count;
449 		urb->actual_length += length;
450 		d->actual_length = length;
451 
452 		d->status = status;
453 
454 		/* see if we are done */
455 		done = (++qh->iso_idx >= urb->number_of_packets);
456 	} else {
457 		/* non-isoch */
458 		buf = buffer + qh->offset;
459 		length = urb->transfer_buffer_length - qh->offset;
460 		if (rx_count > length) {
461 			if (urb->status == -EINPROGRESS)
462 				urb->status = -EOVERFLOW;
463 			musb_dbg(musb, "OVERFLOW %d into %d", rx_count, length);
464 			do_flush = 1;
465 		} else
466 			length = rx_count;
467 		urb->actual_length += length;
468 		qh->offset += length;
469 
470 		/* see if we are done */
471 		done = (urb->actual_length == urb->transfer_buffer_length)
472 			|| (rx_count < qh->maxpacket)
473 			|| (urb->status != -EINPROGRESS);
474 		if (done
475 				&& (urb->status == -EINPROGRESS)
476 				&& (urb->transfer_flags & URB_SHORT_NOT_OK)
477 				&& (urb->actual_length
478 					< urb->transfer_buffer_length))
479 			urb->status = -EREMOTEIO;
480 	}
481 
482 	musb_read_fifo(hw_ep, length, buf);
483 
484 	csr = musb_readw(epio, MUSB_RXCSR);
485 	csr |= MUSB_RXCSR_H_WZC_BITS;
486 	if (unlikely(do_flush))
487 		musb_h_flush_rxfifo(hw_ep, csr);
488 	else {
489 		/* REVISIT this assumes AUTOCLEAR is never set */
490 		csr &= ~(MUSB_RXCSR_RXPKTRDY | MUSB_RXCSR_H_REQPKT);
491 		if (!done)
492 			csr |= MUSB_RXCSR_H_REQPKT;
493 		musb_writew(epio, MUSB_RXCSR, csr);
494 	}
495 
496 	return done;
497 }
498 
499 /* we don't always need to reinit a given side of an endpoint...
500  * when we do, use tx/rx reinit routine and then construct a new CSR
501  * to address data toggle, NYET, and DMA or PIO.
502  *
503  * it's possible that driver bugs (especially for DMA) or aborting a
504  * transfer might have left the endpoint busier than it should be.
505  * the busy/not-empty tests are basically paranoia.
506  */
507 static void
508 musb_rx_reinit(struct musb *musb, struct musb_qh *qh, u8 epnum)
509 {
510 	struct musb_hw_ep *ep = musb->endpoints + epnum;
511 	u16	csr;
512 
513 	/* NOTE:  we know the "rx" fifo reinit never triggers for ep0.
514 	 * That always uses tx_reinit since ep0 repurposes TX register
515 	 * offsets; the initial SETUP packet is also a kind of OUT.
516 	 */
517 
518 	/* if programmed for Tx, put it in RX mode */
519 	if (ep->is_shared_fifo) {
520 		csr = musb_readw(ep->regs, MUSB_TXCSR);
521 		if (csr & MUSB_TXCSR_MODE) {
522 			musb_h_tx_flush_fifo(ep);
523 			csr = musb_readw(ep->regs, MUSB_TXCSR);
524 			musb_writew(ep->regs, MUSB_TXCSR,
525 				    csr | MUSB_TXCSR_FRCDATATOG);
526 		}
527 
528 		/*
529 		 * Clear the MODE bit (and everything else) to enable Rx.
530 		 * NOTE: we mustn't clear the DMAMODE bit before DMAENAB.
531 		 */
532 		if (csr & MUSB_TXCSR_DMAMODE)
533 			musb_writew(ep->regs, MUSB_TXCSR, MUSB_TXCSR_DMAMODE);
534 		musb_writew(ep->regs, MUSB_TXCSR, 0);
535 
536 	/* scrub all previous state, clearing toggle */
537 	}
538 	csr = musb_readw(ep->regs, MUSB_RXCSR);
539 	if (csr & MUSB_RXCSR_RXPKTRDY)
540 		WARNING("rx%d, packet/%d ready?\n", ep->epnum,
541 			musb_readw(ep->regs, MUSB_RXCOUNT));
542 
543 	musb_h_flush_rxfifo(ep, MUSB_RXCSR_CLRDATATOG);
544 
545 	/* target addr and (for multipoint) hub addr/port */
546 	if (musb->is_multipoint) {
547 		musb_write_rxfunaddr(musb, epnum, qh->addr_reg);
548 		musb_write_rxhubaddr(musb, epnum, qh->h_addr_reg);
549 		musb_write_rxhubport(musb, epnum, qh->h_port_reg);
550 	} else
551 		musb_writeb(musb->mregs, MUSB_FADDR, qh->addr_reg);
552 
553 	/* protocol/endpoint, interval/NAKlimit, i/o size */
554 	musb_writeb(ep->regs, MUSB_RXTYPE, qh->type_reg);
555 	musb_writeb(ep->regs, MUSB_RXINTERVAL, qh->intv_reg);
556 	/* NOTE: bulk combining rewrites high bits of maxpacket */
557 	/* Set RXMAXP with the FIFO size of the endpoint
558 	 * to disable double buffer mode.
559 	 */
560 	musb_writew(ep->regs, MUSB_RXMAXP,
561 			qh->maxpacket | ((qh->hb_mult - 1) << 11));
562 
563 	ep->rx_reinit = 0;
564 }
565 
566 static void musb_tx_dma_set_mode_mentor(struct musb_hw_ep *hw_ep,
567 					struct musb_qh *qh,
568 					u32 *length, u8 *mode)
569 {
570 	struct dma_channel	*channel = hw_ep->tx_channel;
571 	void __iomem		*epio = hw_ep->regs;
572 	u16			pkt_size = qh->maxpacket;
573 	u16			csr;
574 
575 	if (*length > channel->max_len)
576 		*length = channel->max_len;
577 
578 	csr = musb_readw(epio, MUSB_TXCSR);
579 	if (*length > pkt_size) {
580 		*mode = 1;
581 		csr |= MUSB_TXCSR_DMAMODE | MUSB_TXCSR_DMAENAB;
582 		/* autoset shouldn't be set in high bandwidth */
583 		/*
584 		 * Enable Autoset according to table
585 		 * below
586 		 * bulk_split hb_mult	Autoset_Enable
587 		 *	0	1	Yes(Normal)
588 		 *	0	>1	No(High BW ISO)
589 		 *	1	1	Yes(HS bulk)
590 		 *	1	>1	Yes(FS bulk)
591 		 */
592 		if (qh->hb_mult == 1 || (qh->hb_mult > 1 &&
593 					can_bulk_split(hw_ep->musb, qh->type)))
594 			csr |= MUSB_TXCSR_AUTOSET;
595 	} else {
596 		*mode = 0;
597 		csr &= ~(MUSB_TXCSR_AUTOSET | MUSB_TXCSR_DMAMODE);
598 		csr |= MUSB_TXCSR_DMAENAB; /* against programmer's guide */
599 	}
600 	channel->desired_mode = *mode;
601 	musb_writew(epio, MUSB_TXCSR, csr);
602 }
603 
604 static void musb_tx_dma_set_mode_cppi_tusb(struct musb_hw_ep *hw_ep,
605 					   struct urb *urb,
606 					   u8 *mode)
607 {
608 	struct dma_channel *channel = hw_ep->tx_channel;
609 
610 	channel->actual_len = 0;
611 
612 	/*
613 	 * TX uses "RNDIS" mode automatically but needs help
614 	 * to identify the zero-length-final-packet case.
615 	 */
616 	*mode = (urb->transfer_flags & URB_ZERO_PACKET) ? 1 : 0;
617 }
618 
619 static bool musb_tx_dma_program(struct dma_controller *dma,
620 		struct musb_hw_ep *hw_ep, struct musb_qh *qh,
621 		struct urb *urb, u32 offset, u32 length)
622 {
623 	struct dma_channel	*channel = hw_ep->tx_channel;
624 	u16			pkt_size = qh->maxpacket;
625 	u8			mode;
626 
627 	if (musb_dma_inventra(hw_ep->musb) || musb_dma_ux500(hw_ep->musb))
628 		musb_tx_dma_set_mode_mentor(hw_ep, qh,
629 					    &length, &mode);
630 	else if (is_cppi_enabled(hw_ep->musb) || tusb_dma_omap(hw_ep->musb))
631 		musb_tx_dma_set_mode_cppi_tusb(hw_ep, urb, &mode);
632 	else
633 		return false;
634 
635 	qh->segsize = length;
636 
637 	/*
638 	 * Ensure the data reaches to main memory before starting
639 	 * DMA transfer
640 	 */
641 	wmb();
642 
643 	if (!dma->channel_program(channel, pkt_size, mode,
644 			urb->transfer_dma + offset, length)) {
645 		void __iomem *epio = hw_ep->regs;
646 		u16 csr;
647 
648 		dma->channel_release(channel);
649 		hw_ep->tx_channel = NULL;
650 
651 		csr = musb_readw(epio, MUSB_TXCSR);
652 		csr &= ~(MUSB_TXCSR_AUTOSET | MUSB_TXCSR_DMAENAB);
653 		musb_writew(epio, MUSB_TXCSR, csr | MUSB_TXCSR_H_WZC_BITS);
654 		return false;
655 	}
656 	return true;
657 }
658 
659 /*
660  * Program an HDRC endpoint as per the given URB
661  * Context: irqs blocked, controller lock held
662  */
663 static void musb_ep_program(struct musb *musb, u8 epnum,
664 			struct urb *urb, int is_out,
665 			u8 *buf, u32 offset, u32 len)
666 {
667 	struct dma_controller	*dma_controller;
668 	struct dma_channel	*dma_channel;
669 	u8			dma_ok;
670 	void __iomem		*mbase = musb->mregs;
671 	struct musb_hw_ep	*hw_ep = musb->endpoints + epnum;
672 	void __iomem		*epio = hw_ep->regs;
673 	struct musb_qh		*qh = musb_ep_get_qh(hw_ep, !is_out);
674 	u16			packet_sz = qh->maxpacket;
675 	u8			use_dma = 1;
676 	u16			csr;
677 
678 	musb_dbg(musb, "%s hw%d urb %p spd%d dev%d ep%d%s "
679 				"h_addr%02x h_port%02x bytes %d",
680 			is_out ? "-->" : "<--",
681 			epnum, urb, urb->dev->speed,
682 			qh->addr_reg, qh->epnum, is_out ? "out" : "in",
683 			qh->h_addr_reg, qh->h_port_reg,
684 			len);
685 
686 	musb_ep_select(mbase, epnum);
687 
688 	if (is_out && !len) {
689 		use_dma = 0;
690 		csr = musb_readw(epio, MUSB_TXCSR);
691 		csr &= ~MUSB_TXCSR_DMAENAB;
692 		musb_writew(epio, MUSB_TXCSR, csr);
693 		hw_ep->tx_channel = NULL;
694 	}
695 
696 	/* candidate for DMA? */
697 	dma_controller = musb->dma_controller;
698 	if (use_dma && is_dma_capable() && epnum && dma_controller) {
699 		dma_channel = is_out ? hw_ep->tx_channel : hw_ep->rx_channel;
700 		if (!dma_channel) {
701 			dma_channel = dma_controller->channel_alloc(
702 					dma_controller, hw_ep, is_out);
703 			if (is_out)
704 				hw_ep->tx_channel = dma_channel;
705 			else
706 				hw_ep->rx_channel = dma_channel;
707 		}
708 	} else
709 		dma_channel = NULL;
710 
711 	/* make sure we clear DMAEnab, autoSet bits from previous run */
712 
713 	/* OUT/transmit/EP0 or IN/receive? */
714 	if (is_out) {
715 		u16	csr;
716 		u16	int_txe;
717 		u16	load_count;
718 
719 		csr = musb_readw(epio, MUSB_TXCSR);
720 
721 		/* disable interrupt in case we flush */
722 		int_txe = musb->intrtxe;
723 		musb_writew(mbase, MUSB_INTRTXE, int_txe & ~(1 << epnum));
724 
725 		/* general endpoint setup */
726 		if (epnum) {
727 			/* flush all old state, set default */
728 			/*
729 			 * We could be flushing valid
730 			 * packets in double buffering
731 			 * case
732 			 */
733 			if (!hw_ep->tx_double_buffered)
734 				musb_h_tx_flush_fifo(hw_ep);
735 
736 			/*
737 			 * We must not clear the DMAMODE bit before or in
738 			 * the same cycle with the DMAENAB bit, so we clear
739 			 * the latter first...
740 			 */
741 			csr &= ~(MUSB_TXCSR_H_NAKTIMEOUT
742 					| MUSB_TXCSR_AUTOSET
743 					| MUSB_TXCSR_DMAENAB
744 					| MUSB_TXCSR_FRCDATATOG
745 					| MUSB_TXCSR_H_RXSTALL
746 					| MUSB_TXCSR_H_ERROR
747 					| MUSB_TXCSR_TXPKTRDY
748 					);
749 			csr |= MUSB_TXCSR_MODE;
750 
751 			if (!hw_ep->tx_double_buffered)
752 				csr |= musb->io.set_toggle(qh, is_out, urb);
753 
754 			musb_writew(epio, MUSB_TXCSR, csr);
755 			/* REVISIT may need to clear FLUSHFIFO ... */
756 			csr &= ~MUSB_TXCSR_DMAMODE;
757 			musb_writew(epio, MUSB_TXCSR, csr);
758 			csr = musb_readw(epio, MUSB_TXCSR);
759 		} else {
760 			/* endpoint 0: just flush */
761 			musb_h_ep0_flush_fifo(hw_ep);
762 		}
763 
764 		/* target addr and (for multipoint) hub addr/port */
765 		if (musb->is_multipoint) {
766 			musb_write_txfunaddr(musb, epnum, qh->addr_reg);
767 			musb_write_txhubaddr(musb, epnum, qh->h_addr_reg);
768 			musb_write_txhubport(musb, epnum, qh->h_port_reg);
769 /* FIXME if !epnum, do the same for RX ... */
770 		} else
771 			musb_writeb(mbase, MUSB_FADDR, qh->addr_reg);
772 
773 		/* protocol/endpoint/interval/NAKlimit */
774 		if (epnum) {
775 			musb_writeb(epio, MUSB_TXTYPE, qh->type_reg);
776 			if (can_bulk_split(musb, qh->type)) {
777 				qh->hb_mult = hw_ep->max_packet_sz_tx
778 						/ packet_sz;
779 				musb_writew(epio, MUSB_TXMAXP, packet_sz
780 					| ((qh->hb_mult) - 1) << 11);
781 			} else {
782 				musb_writew(epio, MUSB_TXMAXP,
783 						qh->maxpacket |
784 						((qh->hb_mult - 1) << 11));
785 			}
786 			musb_writeb(epio, MUSB_TXINTERVAL, qh->intv_reg);
787 		} else {
788 			musb_writeb(epio, MUSB_NAKLIMIT0, qh->intv_reg);
789 			if (musb->is_multipoint)
790 				musb_writeb(epio, MUSB_TYPE0,
791 						qh->type_reg);
792 		}
793 
794 		if (can_bulk_split(musb, qh->type))
795 			load_count = min((u32) hw_ep->max_packet_sz_tx,
796 						len);
797 		else
798 			load_count = min((u32) packet_sz, len);
799 
800 		if (dma_channel && musb_tx_dma_program(dma_controller,
801 					hw_ep, qh, urb, offset, len))
802 			load_count = 0;
803 
804 		if (load_count) {
805 			/* PIO to load FIFO */
806 			qh->segsize = load_count;
807 			if (!buf) {
808 				sg_miter_start(&qh->sg_miter, urb->sg, 1,
809 						SG_MITER_ATOMIC
810 						| SG_MITER_FROM_SG);
811 				if (!sg_miter_next(&qh->sg_miter)) {
812 					dev_err(musb->controller,
813 							"error: sg"
814 							"list empty\n");
815 					sg_miter_stop(&qh->sg_miter);
816 					goto finish;
817 				}
818 				buf = qh->sg_miter.addr + urb->sg->offset +
819 					urb->actual_length;
820 				load_count = min_t(u32, load_count,
821 						qh->sg_miter.length);
822 				musb_write_fifo(hw_ep, load_count, buf);
823 				qh->sg_miter.consumed = load_count;
824 				sg_miter_stop(&qh->sg_miter);
825 			} else
826 				musb_write_fifo(hw_ep, load_count, buf);
827 		}
828 finish:
829 		/* re-enable interrupt */
830 		musb_writew(mbase, MUSB_INTRTXE, int_txe);
831 
832 	/* IN/receive */
833 	} else {
834 		u16 csr = 0;
835 
836 		if (hw_ep->rx_reinit) {
837 			musb_rx_reinit(musb, qh, epnum);
838 			csr |= musb->io.set_toggle(qh, is_out, urb);
839 
840 			if (qh->type == USB_ENDPOINT_XFER_INT)
841 				csr |= MUSB_RXCSR_DISNYET;
842 
843 		} else {
844 			csr = musb_readw(hw_ep->regs, MUSB_RXCSR);
845 
846 			if (csr & (MUSB_RXCSR_RXPKTRDY
847 					| MUSB_RXCSR_DMAENAB
848 					| MUSB_RXCSR_H_REQPKT))
849 				ERR("broken !rx_reinit, ep%d csr %04x\n",
850 						hw_ep->epnum, csr);
851 
852 			/* scrub any stale state, leaving toggle alone */
853 			csr &= MUSB_RXCSR_DISNYET;
854 		}
855 
856 		/* kick things off */
857 
858 		if ((is_cppi_enabled(musb) || tusb_dma_omap(musb)) && dma_channel) {
859 			/* Candidate for DMA */
860 			dma_channel->actual_len = 0L;
861 			qh->segsize = len;
862 
863 			/* AUTOREQ is in a DMA register */
864 			musb_writew(hw_ep->regs, MUSB_RXCSR, csr);
865 			csr = musb_readw(hw_ep->regs, MUSB_RXCSR);
866 
867 			/*
868 			 * Unless caller treats short RX transfers as
869 			 * errors, we dare not queue multiple transfers.
870 			 */
871 			dma_ok = dma_controller->channel_program(dma_channel,
872 					packet_sz, !(urb->transfer_flags &
873 						     URB_SHORT_NOT_OK),
874 					urb->transfer_dma + offset,
875 					qh->segsize);
876 			if (!dma_ok) {
877 				dma_controller->channel_release(dma_channel);
878 				hw_ep->rx_channel = dma_channel = NULL;
879 			} else
880 				csr |= MUSB_RXCSR_DMAENAB;
881 		}
882 
883 		csr |= MUSB_RXCSR_H_REQPKT;
884 		musb_dbg(musb, "RXCSR%d := %04x", epnum, csr);
885 		musb_writew(hw_ep->regs, MUSB_RXCSR, csr);
886 		csr = musb_readw(hw_ep->regs, MUSB_RXCSR);
887 	}
888 }
889 
890 /* Schedule next QH from musb->in_bulk/out_bulk and move the current qh to
891  * the end; avoids starvation for other endpoints.
892  */
893 static void musb_bulk_nak_timeout(struct musb *musb, struct musb_hw_ep *ep,
894 	int is_in)
895 {
896 	struct dma_channel	*dma;
897 	struct urb		*urb;
898 	void __iomem		*mbase = musb->mregs;
899 	void __iomem		*epio = ep->regs;
900 	struct musb_qh		*cur_qh, *next_qh;
901 	u16			rx_csr, tx_csr;
902 	u16			toggle;
903 
904 	musb_ep_select(mbase, ep->epnum);
905 	if (is_in) {
906 		dma = is_dma_capable() ? ep->rx_channel : NULL;
907 
908 		/*
909 		 * Need to stop the transaction by clearing REQPKT first
910 		 * then the NAK Timeout bit ref MUSBMHDRC USB 2.0 HIGH-SPEED
911 		 * DUAL-ROLE CONTROLLER Programmer's Guide, section 9.2.2
912 		 */
913 		rx_csr = musb_readw(epio, MUSB_RXCSR);
914 		rx_csr |= MUSB_RXCSR_H_WZC_BITS;
915 		rx_csr &= ~MUSB_RXCSR_H_REQPKT;
916 		musb_writew(epio, MUSB_RXCSR, rx_csr);
917 		rx_csr &= ~MUSB_RXCSR_DATAERROR;
918 		musb_writew(epio, MUSB_RXCSR, rx_csr);
919 
920 		cur_qh = first_qh(&musb->in_bulk);
921 	} else {
922 		dma = is_dma_capable() ? ep->tx_channel : NULL;
923 
924 		/* clear nak timeout bit */
925 		tx_csr = musb_readw(epio, MUSB_TXCSR);
926 		tx_csr |= MUSB_TXCSR_H_WZC_BITS;
927 		tx_csr &= ~MUSB_TXCSR_H_NAKTIMEOUT;
928 		musb_writew(epio, MUSB_TXCSR, tx_csr);
929 
930 		cur_qh = first_qh(&musb->out_bulk);
931 	}
932 	if (cur_qh) {
933 		urb = next_urb(cur_qh);
934 		if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
935 			dma->status = MUSB_DMA_STATUS_CORE_ABORT;
936 			musb->dma_controller->channel_abort(dma);
937 			urb->actual_length += dma->actual_len;
938 			dma->actual_len = 0L;
939 		}
940 		toggle = musb->io.get_toggle(cur_qh, !is_in);
941 		usb_settoggle(urb->dev, cur_qh->epnum, !is_in, toggle ? 1 : 0);
942 
943 		if (is_in) {
944 			/* move cur_qh to end of queue */
945 			list_move_tail(&cur_qh->ring, &musb->in_bulk);
946 
947 			/* get the next qh from musb->in_bulk */
948 			next_qh = first_qh(&musb->in_bulk);
949 
950 			/* set rx_reinit and schedule the next qh */
951 			ep->rx_reinit = 1;
952 		} else {
953 			/* move cur_qh to end of queue */
954 			list_move_tail(&cur_qh->ring, &musb->out_bulk);
955 
956 			/* get the next qh from musb->out_bulk */
957 			next_qh = first_qh(&musb->out_bulk);
958 
959 			/* set tx_reinit and schedule the next qh */
960 			ep->tx_reinit = 1;
961 		}
962 
963 		if (next_qh)
964 			musb_start_urb(musb, is_in, next_qh);
965 	}
966 }
967 
968 /*
969  * Service the default endpoint (ep0) as host.
970  * Return true until it's time to start the status stage.
971  */
972 static bool musb_h_ep0_continue(struct musb *musb, u16 len, struct urb *urb)
973 {
974 	bool			 more = false;
975 	u8			*fifo_dest = NULL;
976 	u16			fifo_count = 0;
977 	struct musb_hw_ep	*hw_ep = musb->control_ep;
978 	struct musb_qh		*qh = hw_ep->in_qh;
979 	struct usb_ctrlrequest	*request;
980 
981 	switch (musb->ep0_stage) {
982 	case MUSB_EP0_IN:
983 		fifo_dest = urb->transfer_buffer + urb->actual_length;
984 		fifo_count = min_t(size_t, len, urb->transfer_buffer_length -
985 				   urb->actual_length);
986 		if (fifo_count < len)
987 			urb->status = -EOVERFLOW;
988 
989 		musb_read_fifo(hw_ep, fifo_count, fifo_dest);
990 
991 		urb->actual_length += fifo_count;
992 		if (len < qh->maxpacket) {
993 			/* always terminate on short read; it's
994 			 * rarely reported as an error.
995 			 */
996 		} else if (urb->actual_length <
997 				urb->transfer_buffer_length)
998 			more = true;
999 		break;
1000 	case MUSB_EP0_START:
1001 		request = (struct usb_ctrlrequest *) urb->setup_packet;
1002 
1003 		if (!request->wLength) {
1004 			musb_dbg(musb, "start no-DATA");
1005 			break;
1006 		} else if (request->bRequestType & USB_DIR_IN) {
1007 			musb_dbg(musb, "start IN-DATA");
1008 			musb->ep0_stage = MUSB_EP0_IN;
1009 			more = true;
1010 			break;
1011 		} else {
1012 			musb_dbg(musb, "start OUT-DATA");
1013 			musb->ep0_stage = MUSB_EP0_OUT;
1014 			more = true;
1015 		}
1016 		fallthrough;
1017 	case MUSB_EP0_OUT:
1018 		fifo_count = min_t(size_t, qh->maxpacket,
1019 				   urb->transfer_buffer_length -
1020 				   urb->actual_length);
1021 		if (fifo_count) {
1022 			fifo_dest = (u8 *) (urb->transfer_buffer
1023 					+ urb->actual_length);
1024 			musb_dbg(musb, "Sending %d byte%s to ep0 fifo %p",
1025 					fifo_count,
1026 					(fifo_count == 1) ? "" : "s",
1027 					fifo_dest);
1028 			musb_write_fifo(hw_ep, fifo_count, fifo_dest);
1029 
1030 			urb->actual_length += fifo_count;
1031 			more = true;
1032 		}
1033 		break;
1034 	default:
1035 		ERR("bogus ep0 stage %d\n", musb->ep0_stage);
1036 		break;
1037 	}
1038 
1039 	return more;
1040 }
1041 
1042 /*
1043  * Handle default endpoint interrupt as host. Only called in IRQ time
1044  * from musb_interrupt().
1045  *
1046  * called with controller irqlocked
1047  */
1048 irqreturn_t musb_h_ep0_irq(struct musb *musb)
1049 {
1050 	struct urb		*urb;
1051 	u16			csr, len;
1052 	int			status = 0;
1053 	void __iomem		*mbase = musb->mregs;
1054 	struct musb_hw_ep	*hw_ep = musb->control_ep;
1055 	void __iomem		*epio = hw_ep->regs;
1056 	struct musb_qh		*qh = hw_ep->in_qh;
1057 	bool			complete = false;
1058 	irqreturn_t		retval = IRQ_NONE;
1059 
1060 	/* ep0 only has one queue, "in" */
1061 	urb = next_urb(qh);
1062 
1063 	musb_ep_select(mbase, 0);
1064 	csr = musb_readw(epio, MUSB_CSR0);
1065 	len = (csr & MUSB_CSR0_RXPKTRDY)
1066 			? musb_readb(epio, MUSB_COUNT0)
1067 			: 0;
1068 
1069 	musb_dbg(musb, "<== csr0 %04x, qh %p, count %d, urb %p, stage %d",
1070 		csr, qh, len, urb, musb->ep0_stage);
1071 
1072 	/* if we just did status stage, we are done */
1073 	if (MUSB_EP0_STATUS == musb->ep0_stage) {
1074 		retval = IRQ_HANDLED;
1075 		complete = true;
1076 	}
1077 
1078 	/* prepare status */
1079 	if (csr & MUSB_CSR0_H_RXSTALL) {
1080 		musb_dbg(musb, "STALLING ENDPOINT");
1081 		status = -EPIPE;
1082 
1083 	} else if (csr & MUSB_CSR0_H_ERROR) {
1084 		musb_dbg(musb, "no response, csr0 %04x", csr);
1085 		status = -EPROTO;
1086 
1087 	} else if (csr & MUSB_CSR0_H_NAKTIMEOUT) {
1088 		musb_dbg(musb, "control NAK timeout");
1089 
1090 		/* NOTE:  this code path would be a good place to PAUSE a
1091 		 * control transfer, if another one is queued, so that
1092 		 * ep0 is more likely to stay busy.  That's already done
1093 		 * for bulk RX transfers.
1094 		 *
1095 		 * if (qh->ring.next != &musb->control), then
1096 		 * we have a candidate... NAKing is *NOT* an error
1097 		 */
1098 		musb_writew(epio, MUSB_CSR0, 0);
1099 		retval = IRQ_HANDLED;
1100 	}
1101 
1102 	if (status) {
1103 		musb_dbg(musb, "aborting");
1104 		retval = IRQ_HANDLED;
1105 		if (urb)
1106 			urb->status = status;
1107 		complete = true;
1108 
1109 		/* use the proper sequence to abort the transfer */
1110 		if (csr & MUSB_CSR0_H_REQPKT) {
1111 			csr &= ~MUSB_CSR0_H_REQPKT;
1112 			musb_writew(epio, MUSB_CSR0, csr);
1113 			csr &= ~MUSB_CSR0_H_NAKTIMEOUT;
1114 			musb_writew(epio, MUSB_CSR0, csr);
1115 		} else {
1116 			musb_h_ep0_flush_fifo(hw_ep);
1117 		}
1118 
1119 		musb_writeb(epio, MUSB_NAKLIMIT0, 0);
1120 
1121 		/* clear it */
1122 		musb_writew(epio, MUSB_CSR0, 0);
1123 	}
1124 
1125 	if (unlikely(!urb)) {
1126 		/* stop endpoint since we have no place for its data, this
1127 		 * SHOULD NEVER HAPPEN! */
1128 		ERR("no URB for end 0\n");
1129 
1130 		musb_h_ep0_flush_fifo(hw_ep);
1131 		goto done;
1132 	}
1133 
1134 	if (!complete) {
1135 		/* call common logic and prepare response */
1136 		if (musb_h_ep0_continue(musb, len, urb)) {
1137 			/* more packets required */
1138 			csr = (MUSB_EP0_IN == musb->ep0_stage)
1139 				?  MUSB_CSR0_H_REQPKT : MUSB_CSR0_TXPKTRDY;
1140 		} else {
1141 			/* data transfer complete; perform status phase */
1142 			if (usb_pipeout(urb->pipe)
1143 					|| !urb->transfer_buffer_length)
1144 				csr = MUSB_CSR0_H_STATUSPKT
1145 					| MUSB_CSR0_H_REQPKT;
1146 			else
1147 				csr = MUSB_CSR0_H_STATUSPKT
1148 					| MUSB_CSR0_TXPKTRDY;
1149 
1150 			/* disable ping token in status phase */
1151 			csr |= MUSB_CSR0_H_DIS_PING;
1152 
1153 			/* flag status stage */
1154 			musb->ep0_stage = MUSB_EP0_STATUS;
1155 
1156 			musb_dbg(musb, "ep0 STATUS, csr %04x", csr);
1157 
1158 		}
1159 		musb_writew(epio, MUSB_CSR0, csr);
1160 		retval = IRQ_HANDLED;
1161 	} else
1162 		musb->ep0_stage = MUSB_EP0_IDLE;
1163 
1164 	/* call completion handler if done */
1165 	if (complete)
1166 		musb_advance_schedule(musb, urb, hw_ep, 1);
1167 done:
1168 	return retval;
1169 }
1170 
1171 
1172 #ifdef CONFIG_USB_INVENTRA_DMA
1173 
1174 /* Host side TX (OUT) using Mentor DMA works as follows:
1175 	submit_urb ->
1176 		- if queue was empty, Program Endpoint
1177 		- ... which starts DMA to fifo in mode 1 or 0
1178 
1179 	DMA Isr (transfer complete) -> TxAvail()
1180 		- Stop DMA (~DmaEnab)	(<--- Alert ... currently happens
1181 					only in musb_cleanup_urb)
1182 		- TxPktRdy has to be set in mode 0 or for
1183 			short packets in mode 1.
1184 */
1185 
1186 #endif
1187 
1188 /* Service a Tx-Available or dma completion irq for the endpoint */
1189 void musb_host_tx(struct musb *musb, u8 epnum)
1190 {
1191 	int			pipe;
1192 	bool			done = false;
1193 	u16			tx_csr;
1194 	size_t			length = 0;
1195 	size_t			offset = 0;
1196 	struct musb_hw_ep	*hw_ep = musb->endpoints + epnum;
1197 	void __iomem		*epio = hw_ep->regs;
1198 	struct musb_qh		*qh = hw_ep->out_qh;
1199 	struct urb		*urb = next_urb(qh);
1200 	u32			status = 0;
1201 	void __iomem		*mbase = musb->mregs;
1202 	struct dma_channel	*dma;
1203 	bool			transfer_pending = false;
1204 
1205 	musb_ep_select(mbase, epnum);
1206 	tx_csr = musb_readw(epio, MUSB_TXCSR);
1207 
1208 	/* with CPPI, DMA sometimes triggers "extra" irqs */
1209 	if (!urb) {
1210 		musb_dbg(musb, "extra TX%d ready, csr %04x", epnum, tx_csr);
1211 		return;
1212 	}
1213 
1214 	pipe = urb->pipe;
1215 	dma = is_dma_capable() ? hw_ep->tx_channel : NULL;
1216 	trace_musb_urb_tx(musb, urb);
1217 	musb_dbg(musb, "OUT/TX%d end, csr %04x%s", epnum, tx_csr,
1218 			dma ? ", dma" : "");
1219 
1220 	/* check for errors */
1221 	if (tx_csr & MUSB_TXCSR_H_RXSTALL) {
1222 		/* dma was disabled, fifo flushed */
1223 		musb_dbg(musb, "TX end %d stall", epnum);
1224 
1225 		/* stall; record URB status */
1226 		status = -EPIPE;
1227 
1228 	} else if (tx_csr & MUSB_TXCSR_H_ERROR) {
1229 		/* (NON-ISO) dma was disabled, fifo flushed */
1230 		musb_dbg(musb, "TX 3strikes on ep=%d", epnum);
1231 
1232 		status = -ETIMEDOUT;
1233 
1234 	} else if (tx_csr & MUSB_TXCSR_H_NAKTIMEOUT) {
1235 		if (USB_ENDPOINT_XFER_BULK == qh->type && qh->mux == 1
1236 				&& !list_is_singular(&musb->out_bulk)) {
1237 			musb_dbg(musb, "NAK timeout on TX%d ep", epnum);
1238 			musb_bulk_nak_timeout(musb, hw_ep, 0);
1239 		} else {
1240 			musb_dbg(musb, "TX ep%d device not responding", epnum);
1241 			/* NOTE:  this code path would be a good place to PAUSE a
1242 			 * transfer, if there's some other (nonperiodic) tx urb
1243 			 * that could use this fifo.  (dma complicates it...)
1244 			 * That's already done for bulk RX transfers.
1245 			 *
1246 			 * if (bulk && qh->ring.next != &musb->out_bulk), then
1247 			 * we have a candidate... NAKing is *NOT* an error
1248 			 */
1249 			musb_ep_select(mbase, epnum);
1250 			musb_writew(epio, MUSB_TXCSR,
1251 					MUSB_TXCSR_H_WZC_BITS
1252 					| MUSB_TXCSR_TXPKTRDY);
1253 		}
1254 		return;
1255 	}
1256 
1257 done:
1258 	if (status) {
1259 		if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1260 			dma->status = MUSB_DMA_STATUS_CORE_ABORT;
1261 			musb->dma_controller->channel_abort(dma);
1262 		}
1263 
1264 		/* do the proper sequence to abort the transfer in the
1265 		 * usb core; the dma engine should already be stopped.
1266 		 */
1267 		musb_h_tx_flush_fifo(hw_ep);
1268 		tx_csr &= ~(MUSB_TXCSR_AUTOSET
1269 				| MUSB_TXCSR_DMAENAB
1270 				| MUSB_TXCSR_H_ERROR
1271 				| MUSB_TXCSR_H_RXSTALL
1272 				| MUSB_TXCSR_H_NAKTIMEOUT
1273 				);
1274 
1275 		musb_ep_select(mbase, epnum);
1276 		musb_writew(epio, MUSB_TXCSR, tx_csr);
1277 		/* REVISIT may need to clear FLUSHFIFO ... */
1278 		musb_writew(epio, MUSB_TXCSR, tx_csr);
1279 		musb_writeb(epio, MUSB_TXINTERVAL, 0);
1280 
1281 		done = true;
1282 	}
1283 
1284 	/* second cppi case */
1285 	if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1286 		musb_dbg(musb, "extra TX%d ready, csr %04x", epnum, tx_csr);
1287 		return;
1288 	}
1289 
1290 	if (is_dma_capable() && dma && !status) {
1291 		/*
1292 		 * DMA has completed.  But if we're using DMA mode 1 (multi
1293 		 * packet DMA), we need a terminal TXPKTRDY interrupt before
1294 		 * we can consider this transfer completed, lest we trash
1295 		 * its last packet when writing the next URB's data.  So we
1296 		 * switch back to mode 0 to get that interrupt; we'll come
1297 		 * back here once it happens.
1298 		 */
1299 		if (tx_csr & MUSB_TXCSR_DMAMODE) {
1300 			/*
1301 			 * We shouldn't clear DMAMODE with DMAENAB set; so
1302 			 * clear them in a safe order.  That should be OK
1303 			 * once TXPKTRDY has been set (and I've never seen
1304 			 * it being 0 at this moment -- DMA interrupt latency
1305 			 * is significant) but if it hasn't been then we have
1306 			 * no choice but to stop being polite and ignore the
1307 			 * programmer's guide... :-)
1308 			 *
1309 			 * Note that we must write TXCSR with TXPKTRDY cleared
1310 			 * in order not to re-trigger the packet send (this bit
1311 			 * can't be cleared by CPU), and there's another caveat:
1312 			 * TXPKTRDY may be set shortly and then cleared in the
1313 			 * double-buffered FIFO mode, so we do an extra TXCSR
1314 			 * read for debouncing...
1315 			 */
1316 			tx_csr &= musb_readw(epio, MUSB_TXCSR);
1317 			if (tx_csr & MUSB_TXCSR_TXPKTRDY) {
1318 				tx_csr &= ~(MUSB_TXCSR_DMAENAB |
1319 					    MUSB_TXCSR_TXPKTRDY);
1320 				musb_writew(epio, MUSB_TXCSR,
1321 					    tx_csr | MUSB_TXCSR_H_WZC_BITS);
1322 			}
1323 			tx_csr &= ~(MUSB_TXCSR_DMAMODE |
1324 				    MUSB_TXCSR_TXPKTRDY);
1325 			musb_writew(epio, MUSB_TXCSR,
1326 				    tx_csr | MUSB_TXCSR_H_WZC_BITS);
1327 
1328 			/*
1329 			 * There is no guarantee that we'll get an interrupt
1330 			 * after clearing DMAMODE as we might have done this
1331 			 * too late (after TXPKTRDY was cleared by controller).
1332 			 * Re-read TXCSR as we have spoiled its previous value.
1333 			 */
1334 			tx_csr = musb_readw(epio, MUSB_TXCSR);
1335 		}
1336 
1337 		/*
1338 		 * We may get here from a DMA completion or TXPKTRDY interrupt.
1339 		 * In any case, we must check the FIFO status here and bail out
1340 		 * only if the FIFO still has data -- that should prevent the
1341 		 * "missed" TXPKTRDY interrupts and deal with double-buffered
1342 		 * FIFO mode too...
1343 		 */
1344 		if (tx_csr & (MUSB_TXCSR_FIFONOTEMPTY | MUSB_TXCSR_TXPKTRDY)) {
1345 			musb_dbg(musb,
1346 				"DMA complete but FIFO not empty, CSR %04x",
1347 				tx_csr);
1348 			return;
1349 		}
1350 	}
1351 
1352 	if (!status || dma || usb_pipeisoc(pipe)) {
1353 		if (dma)
1354 			length = dma->actual_len;
1355 		else
1356 			length = qh->segsize;
1357 		qh->offset += length;
1358 
1359 		if (usb_pipeisoc(pipe)) {
1360 			struct usb_iso_packet_descriptor	*d;
1361 
1362 			d = urb->iso_frame_desc + qh->iso_idx;
1363 			d->actual_length = length;
1364 			d->status = status;
1365 			if (++qh->iso_idx >= urb->number_of_packets) {
1366 				done = true;
1367 			} else {
1368 				d++;
1369 				offset = d->offset;
1370 				length = d->length;
1371 			}
1372 		} else if (dma && urb->transfer_buffer_length == qh->offset) {
1373 			done = true;
1374 		} else {
1375 			/* see if we need to send more data, or ZLP */
1376 			if (qh->segsize < qh->maxpacket)
1377 				done = true;
1378 			else if (qh->offset == urb->transfer_buffer_length
1379 					&& !(urb->transfer_flags
1380 						& URB_ZERO_PACKET))
1381 				done = true;
1382 			if (!done) {
1383 				offset = qh->offset;
1384 				length = urb->transfer_buffer_length - offset;
1385 				transfer_pending = true;
1386 			}
1387 		}
1388 	}
1389 
1390 	/* urb->status != -EINPROGRESS means request has been faulted,
1391 	 * so we must abort this transfer after cleanup
1392 	 */
1393 	if (urb->status != -EINPROGRESS) {
1394 		done = true;
1395 		if (status == 0)
1396 			status = urb->status;
1397 	}
1398 
1399 	if (done) {
1400 		/* set status */
1401 		urb->status = status;
1402 		urb->actual_length = qh->offset;
1403 		musb_advance_schedule(musb, urb, hw_ep, USB_DIR_OUT);
1404 		return;
1405 	} else if ((usb_pipeisoc(pipe) || transfer_pending) && dma) {
1406 		if (musb_tx_dma_program(musb->dma_controller, hw_ep, qh, urb,
1407 				offset, length)) {
1408 			if (is_cppi_enabled(musb) || tusb_dma_omap(musb))
1409 				musb_h_tx_dma_start(hw_ep);
1410 			return;
1411 		}
1412 	} else	if (tx_csr & MUSB_TXCSR_DMAENAB) {
1413 		musb_dbg(musb, "not complete, but DMA enabled?");
1414 		return;
1415 	}
1416 
1417 	/*
1418 	 * PIO: start next packet in this URB.
1419 	 *
1420 	 * REVISIT: some docs say that when hw_ep->tx_double_buffered,
1421 	 * (and presumably, FIFO is not half-full) we should write *two*
1422 	 * packets before updating TXCSR; other docs disagree...
1423 	 */
1424 	if (length > qh->maxpacket)
1425 		length = qh->maxpacket;
1426 	/* Unmap the buffer so that CPU can use it */
1427 	usb_hcd_unmap_urb_for_dma(musb->hcd, urb);
1428 
1429 	/*
1430 	 * We need to map sg if the transfer_buffer is
1431 	 * NULL.
1432 	 */
1433 	if (!urb->transfer_buffer) {
1434 		/* sg_miter_start is already done in musb_ep_program */
1435 		if (!sg_miter_next(&qh->sg_miter)) {
1436 			dev_err(musb->controller, "error: sg list empty\n");
1437 			sg_miter_stop(&qh->sg_miter);
1438 			status = -EINVAL;
1439 			goto done;
1440 		}
1441 		length = min_t(u32, length, qh->sg_miter.length);
1442 		musb_write_fifo(hw_ep, length, qh->sg_miter.addr);
1443 		qh->sg_miter.consumed = length;
1444 		sg_miter_stop(&qh->sg_miter);
1445 	} else {
1446 		musb_write_fifo(hw_ep, length, urb->transfer_buffer + offset);
1447 	}
1448 
1449 	qh->segsize = length;
1450 
1451 	musb_ep_select(mbase, epnum);
1452 	musb_writew(epio, MUSB_TXCSR,
1453 			MUSB_TXCSR_H_WZC_BITS | MUSB_TXCSR_TXPKTRDY);
1454 }
1455 
1456 #ifdef CONFIG_USB_TI_CPPI41_DMA
1457 /* Seems to set up ISO for cppi41 and not advance len. See commit c57c41d */
1458 static int musb_rx_dma_iso_cppi41(struct dma_controller *dma,
1459 				  struct musb_hw_ep *hw_ep,
1460 				  struct musb_qh *qh,
1461 				  struct urb *urb,
1462 				  size_t len)
1463 {
1464 	struct dma_channel *channel = hw_ep->rx_channel;
1465 	void __iomem *epio = hw_ep->regs;
1466 	dma_addr_t *buf;
1467 	u32 length;
1468 	u16 val;
1469 
1470 	buf = (void *)urb->iso_frame_desc[qh->iso_idx].offset +
1471 		(u32)urb->transfer_dma;
1472 
1473 	length = urb->iso_frame_desc[qh->iso_idx].length;
1474 
1475 	val = musb_readw(epio, MUSB_RXCSR);
1476 	val |= MUSB_RXCSR_DMAENAB;
1477 	musb_writew(hw_ep->regs, MUSB_RXCSR, val);
1478 
1479 	return dma->channel_program(channel, qh->maxpacket, 0,
1480 				   (u32)buf, length);
1481 }
1482 #else
1483 static inline int musb_rx_dma_iso_cppi41(struct dma_controller *dma,
1484 					 struct musb_hw_ep *hw_ep,
1485 					 struct musb_qh *qh,
1486 					 struct urb *urb,
1487 					 size_t len)
1488 {
1489 	return false;
1490 }
1491 #endif
1492 
1493 #if defined(CONFIG_USB_INVENTRA_DMA) || defined(CONFIG_USB_UX500_DMA) || \
1494 	defined(CONFIG_USB_TI_CPPI41_DMA)
1495 /* Host side RX (IN) using Mentor DMA works as follows:
1496 	submit_urb ->
1497 		- if queue was empty, ProgramEndpoint
1498 		- first IN token is sent out (by setting ReqPkt)
1499 	LinuxIsr -> RxReady()
1500 	/\	=> first packet is received
1501 	|	- Set in mode 0 (DmaEnab, ~ReqPkt)
1502 	|		-> DMA Isr (transfer complete) -> RxReady()
1503 	|		    - Ack receive (~RxPktRdy), turn off DMA (~DmaEnab)
1504 	|		    - if urb not complete, send next IN token (ReqPkt)
1505 	|			   |		else complete urb.
1506 	|			   |
1507 	---------------------------
1508  *
1509  * Nuances of mode 1:
1510  *	For short packets, no ack (+RxPktRdy) is sent automatically
1511  *	(even if AutoClear is ON)
1512  *	For full packets, ack (~RxPktRdy) and next IN token (+ReqPkt) is sent
1513  *	automatically => major problem, as collecting the next packet becomes
1514  *	difficult. Hence mode 1 is not used.
1515  *
1516  * REVISIT
1517  *	All we care about at this driver level is that
1518  *       (a) all URBs terminate with REQPKT cleared and fifo(s) empty;
1519  *       (b) termination conditions are: short RX, or buffer full;
1520  *       (c) fault modes include
1521  *           - iff URB_SHORT_NOT_OK, short RX status is -EREMOTEIO.
1522  *             (and that endpoint's dma queue stops immediately)
1523  *           - overflow (full, PLUS more bytes in the terminal packet)
1524  *
1525  *	So for example, usb-storage sets URB_SHORT_NOT_OK, and would
1526  *	thus be a great candidate for using mode 1 ... for all but the
1527  *	last packet of one URB's transfer.
1528  */
1529 static int musb_rx_dma_inventra_cppi41(struct dma_controller *dma,
1530 				       struct musb_hw_ep *hw_ep,
1531 				       struct musb_qh *qh,
1532 				       struct urb *urb,
1533 				       size_t len)
1534 {
1535 	struct dma_channel *channel = hw_ep->rx_channel;
1536 	void __iomem *epio = hw_ep->regs;
1537 	u16 val;
1538 	int pipe;
1539 	bool done;
1540 
1541 	pipe = urb->pipe;
1542 
1543 	if (usb_pipeisoc(pipe)) {
1544 		struct usb_iso_packet_descriptor *d;
1545 
1546 		d = urb->iso_frame_desc + qh->iso_idx;
1547 		d->actual_length = len;
1548 
1549 		/* even if there was an error, we did the dma
1550 		 * for iso_frame_desc->length
1551 		 */
1552 		if (d->status != -EILSEQ && d->status != -EOVERFLOW)
1553 			d->status = 0;
1554 
1555 		if (++qh->iso_idx >= urb->number_of_packets) {
1556 			done = true;
1557 		} else {
1558 			/* REVISIT: Why ignore return value here? */
1559 			if (musb_dma_cppi41(hw_ep->musb))
1560 				done = musb_rx_dma_iso_cppi41(dma, hw_ep, qh,
1561 							      urb, len);
1562 			done = false;
1563 		}
1564 
1565 	} else  {
1566 		/* done if urb buffer is full or short packet is recd */
1567 		done = (urb->actual_length + len >=
1568 			urb->transfer_buffer_length
1569 			|| channel->actual_len < qh->maxpacket
1570 			|| channel->rx_packet_done);
1571 	}
1572 
1573 	/* send IN token for next packet, without AUTOREQ */
1574 	if (!done) {
1575 		val = musb_readw(epio, MUSB_RXCSR);
1576 		val |= MUSB_RXCSR_H_REQPKT;
1577 		musb_writew(epio, MUSB_RXCSR, MUSB_RXCSR_H_WZC_BITS | val);
1578 	}
1579 
1580 	return done;
1581 }
1582 
1583 /* Disadvantage of using mode 1:
1584  *	It's basically usable only for mass storage class; essentially all
1585  *	other protocols also terminate transfers on short packets.
1586  *
1587  * Details:
1588  *	An extra IN token is sent at the end of the transfer (due to AUTOREQ)
1589  *	If you try to use mode 1 for (transfer_buffer_length - 512), and try
1590  *	to use the extra IN token to grab the last packet using mode 0, then
1591  *	the problem is that you cannot be sure when the device will send the
1592  *	last packet and RxPktRdy set. Sometimes the packet is recd too soon
1593  *	such that it gets lost when RxCSR is re-set at the end of the mode 1
1594  *	transfer, while sometimes it is recd just a little late so that if you
1595  *	try to configure for mode 0 soon after the mode 1 transfer is
1596  *	completed, you will find rxcount 0. Okay, so you might think why not
1597  *	wait for an interrupt when the pkt is recd. Well, you won't get any!
1598  */
1599 static int musb_rx_dma_in_inventra_cppi41(struct dma_controller *dma,
1600 					  struct musb_hw_ep *hw_ep,
1601 					  struct musb_qh *qh,
1602 					  struct urb *urb,
1603 					  size_t len,
1604 					  u8 iso_err)
1605 {
1606 	struct musb *musb = hw_ep->musb;
1607 	void __iomem *epio = hw_ep->regs;
1608 	struct dma_channel *channel = hw_ep->rx_channel;
1609 	u16 rx_count, val;
1610 	int length, pipe, done;
1611 	dma_addr_t buf;
1612 
1613 	rx_count = musb_readw(epio, MUSB_RXCOUNT);
1614 	pipe = urb->pipe;
1615 
1616 	if (usb_pipeisoc(pipe)) {
1617 		int d_status = 0;
1618 		struct usb_iso_packet_descriptor *d;
1619 
1620 		d = urb->iso_frame_desc + qh->iso_idx;
1621 
1622 		if (iso_err) {
1623 			d_status = -EILSEQ;
1624 			urb->error_count++;
1625 		}
1626 		if (rx_count > d->length) {
1627 			if (d_status == 0) {
1628 				d_status = -EOVERFLOW;
1629 				urb->error_count++;
1630 			}
1631 			musb_dbg(musb, "** OVERFLOW %d into %d",
1632 				rx_count, d->length);
1633 
1634 			length = d->length;
1635 		} else
1636 			length = rx_count;
1637 		d->status = d_status;
1638 		buf = urb->transfer_dma + d->offset;
1639 	} else {
1640 		length = rx_count;
1641 		buf = urb->transfer_dma + urb->actual_length;
1642 	}
1643 
1644 	channel->desired_mode = 0;
1645 #ifdef USE_MODE1
1646 	/* because of the issue below, mode 1 will
1647 	 * only rarely behave with correct semantics.
1648 	 */
1649 	if ((urb->transfer_flags & URB_SHORT_NOT_OK)
1650 	    && (urb->transfer_buffer_length - urb->actual_length)
1651 	    > qh->maxpacket)
1652 		channel->desired_mode = 1;
1653 	if (rx_count < hw_ep->max_packet_sz_rx) {
1654 		length = rx_count;
1655 		channel->desired_mode = 0;
1656 	} else {
1657 		length = urb->transfer_buffer_length;
1658 	}
1659 #endif
1660 
1661 	/* See comments above on disadvantages of using mode 1 */
1662 	val = musb_readw(epio, MUSB_RXCSR);
1663 	val &= ~MUSB_RXCSR_H_REQPKT;
1664 
1665 	if (channel->desired_mode == 0)
1666 		val &= ~MUSB_RXCSR_H_AUTOREQ;
1667 	else
1668 		val |= MUSB_RXCSR_H_AUTOREQ;
1669 	val |= MUSB_RXCSR_DMAENAB;
1670 
1671 	/* autoclear shouldn't be set in high bandwidth */
1672 	if (qh->hb_mult == 1)
1673 		val |= MUSB_RXCSR_AUTOCLEAR;
1674 
1675 	musb_writew(epio, MUSB_RXCSR, MUSB_RXCSR_H_WZC_BITS | val);
1676 
1677 	/* REVISIT if when actual_length != 0,
1678 	 * transfer_buffer_length needs to be
1679 	 * adjusted first...
1680 	 */
1681 	done = dma->channel_program(channel, qh->maxpacket,
1682 				   channel->desired_mode,
1683 				   buf, length);
1684 
1685 	if (!done) {
1686 		dma->channel_release(channel);
1687 		hw_ep->rx_channel = NULL;
1688 		channel = NULL;
1689 		val = musb_readw(epio, MUSB_RXCSR);
1690 		val &= ~(MUSB_RXCSR_DMAENAB
1691 			 | MUSB_RXCSR_H_AUTOREQ
1692 			 | MUSB_RXCSR_AUTOCLEAR);
1693 		musb_writew(epio, MUSB_RXCSR, val);
1694 	}
1695 
1696 	return done;
1697 }
1698 #else
1699 static inline int musb_rx_dma_inventra_cppi41(struct dma_controller *dma,
1700 					      struct musb_hw_ep *hw_ep,
1701 					      struct musb_qh *qh,
1702 					      struct urb *urb,
1703 					      size_t len)
1704 {
1705 	return false;
1706 }
1707 
1708 static inline int musb_rx_dma_in_inventra_cppi41(struct dma_controller *dma,
1709 						 struct musb_hw_ep *hw_ep,
1710 						 struct musb_qh *qh,
1711 						 struct urb *urb,
1712 						 size_t len,
1713 						 u8 iso_err)
1714 {
1715 	return false;
1716 }
1717 #endif
1718 
1719 /*
1720  * Service an RX interrupt for the given IN endpoint; docs cover bulk, iso,
1721  * and high-bandwidth IN transfer cases.
1722  */
1723 void musb_host_rx(struct musb *musb, u8 epnum)
1724 {
1725 	struct urb		*urb;
1726 	struct musb_hw_ep	*hw_ep = musb->endpoints + epnum;
1727 	struct dma_controller	*c = musb->dma_controller;
1728 	void __iomem		*epio = hw_ep->regs;
1729 	struct musb_qh		*qh = hw_ep->in_qh;
1730 	size_t			xfer_len;
1731 	void __iomem		*mbase = musb->mregs;
1732 	u16			rx_csr, val;
1733 	bool			iso_err = false;
1734 	bool			done = false;
1735 	u32			status;
1736 	struct dma_channel	*dma;
1737 	unsigned int sg_flags = SG_MITER_ATOMIC | SG_MITER_TO_SG;
1738 
1739 	musb_ep_select(mbase, epnum);
1740 
1741 	urb = next_urb(qh);
1742 	dma = is_dma_capable() ? hw_ep->rx_channel : NULL;
1743 	status = 0;
1744 	xfer_len = 0;
1745 
1746 	rx_csr = musb_readw(epio, MUSB_RXCSR);
1747 	val = rx_csr;
1748 
1749 	if (unlikely(!urb)) {
1750 		/* REVISIT -- THIS SHOULD NEVER HAPPEN ... but, at least
1751 		 * usbtest #11 (unlinks) triggers it regularly, sometimes
1752 		 * with fifo full.  (Only with DMA??)
1753 		 */
1754 		musb_dbg(musb, "BOGUS RX%d ready, csr %04x, count %d",
1755 			epnum, val, musb_readw(epio, MUSB_RXCOUNT));
1756 		musb_h_flush_rxfifo(hw_ep, MUSB_RXCSR_CLRDATATOG);
1757 		return;
1758 	}
1759 
1760 	trace_musb_urb_rx(musb, urb);
1761 
1762 	/* check for errors, concurrent stall & unlink is not really
1763 	 * handled yet! */
1764 	if (rx_csr & MUSB_RXCSR_H_RXSTALL) {
1765 		musb_dbg(musb, "RX end %d STALL", epnum);
1766 
1767 		/* stall; record URB status */
1768 		status = -EPIPE;
1769 
1770 	} else if (rx_csr & MUSB_RXCSR_H_ERROR) {
1771 		dev_err(musb->controller, "ep%d RX three-strikes error", epnum);
1772 
1773 		/*
1774 		 * The three-strikes error could only happen when the USB
1775 		 * device is not accessible, for example detached or powered
1776 		 * off. So return the fatal error -ESHUTDOWN so hopefully the
1777 		 * USB device drivers won't immediately resubmit the same URB.
1778 		 */
1779 		status = -ESHUTDOWN;
1780 		musb_writeb(epio, MUSB_RXINTERVAL, 0);
1781 
1782 		rx_csr &= ~MUSB_RXCSR_H_ERROR;
1783 		musb_writew(epio, MUSB_RXCSR, rx_csr);
1784 
1785 	} else if (rx_csr & MUSB_RXCSR_DATAERROR) {
1786 
1787 		if (USB_ENDPOINT_XFER_ISOC != qh->type) {
1788 			musb_dbg(musb, "RX end %d NAK timeout", epnum);
1789 
1790 			/* NOTE: NAKing is *NOT* an error, so we want to
1791 			 * continue.  Except ... if there's a request for
1792 			 * another QH, use that instead of starving it.
1793 			 *
1794 			 * Devices like Ethernet and serial adapters keep
1795 			 * reads posted at all times, which will starve
1796 			 * other devices without this logic.
1797 			 */
1798 			if (usb_pipebulk(urb->pipe)
1799 					&& qh->mux == 1
1800 					&& !list_is_singular(&musb->in_bulk)) {
1801 				musb_bulk_nak_timeout(musb, hw_ep, 1);
1802 				return;
1803 			}
1804 			musb_ep_select(mbase, epnum);
1805 			rx_csr |= MUSB_RXCSR_H_WZC_BITS;
1806 			rx_csr &= ~MUSB_RXCSR_DATAERROR;
1807 			musb_writew(epio, MUSB_RXCSR, rx_csr);
1808 
1809 			goto finish;
1810 		} else {
1811 			musb_dbg(musb, "RX end %d ISO data error", epnum);
1812 			/* packet error reported later */
1813 			iso_err = true;
1814 		}
1815 	} else if (rx_csr & MUSB_RXCSR_INCOMPRX) {
1816 		musb_dbg(musb, "end %d high bandwidth incomplete ISO packet RX",
1817 				epnum);
1818 		status = -EPROTO;
1819 	}
1820 
1821 	/* faults abort the transfer */
1822 	if (status) {
1823 		/* clean up dma and collect transfer count */
1824 		if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1825 			dma->status = MUSB_DMA_STATUS_CORE_ABORT;
1826 			musb->dma_controller->channel_abort(dma);
1827 			xfer_len = dma->actual_len;
1828 		}
1829 		musb_h_flush_rxfifo(hw_ep, MUSB_RXCSR_CLRDATATOG);
1830 		musb_writeb(epio, MUSB_RXINTERVAL, 0);
1831 		done = true;
1832 		goto finish;
1833 	}
1834 
1835 	if (unlikely(dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY)) {
1836 		/* SHOULD NEVER HAPPEN ... but at least DaVinci has done it */
1837 		ERR("RX%d dma busy, csr %04x\n", epnum, rx_csr);
1838 		goto finish;
1839 	}
1840 
1841 	/* thorough shutdown for now ... given more precise fault handling
1842 	 * and better queueing support, we might keep a DMA pipeline going
1843 	 * while processing this irq for earlier completions.
1844 	 */
1845 
1846 	/* FIXME this is _way_ too much in-line logic for Mentor DMA */
1847 	if (!musb_dma_inventra(musb) && !musb_dma_ux500(musb) &&
1848 	    (rx_csr & MUSB_RXCSR_H_REQPKT)) {
1849 		/* REVISIT this happened for a while on some short reads...
1850 		 * the cleanup still needs investigation... looks bad...
1851 		 * and also duplicates dma cleanup code above ... plus,
1852 		 * shouldn't this be the "half full" double buffer case?
1853 		 */
1854 		if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
1855 			dma->status = MUSB_DMA_STATUS_CORE_ABORT;
1856 			musb->dma_controller->channel_abort(dma);
1857 			xfer_len = dma->actual_len;
1858 			done = true;
1859 		}
1860 
1861 		musb_dbg(musb, "RXCSR%d %04x, reqpkt, len %zu%s", epnum, rx_csr,
1862 				xfer_len, dma ? ", dma" : "");
1863 		rx_csr &= ~MUSB_RXCSR_H_REQPKT;
1864 
1865 		musb_ep_select(mbase, epnum);
1866 		musb_writew(epio, MUSB_RXCSR,
1867 				MUSB_RXCSR_H_WZC_BITS | rx_csr);
1868 	}
1869 
1870 	if (dma && (rx_csr & MUSB_RXCSR_DMAENAB)) {
1871 		xfer_len = dma->actual_len;
1872 
1873 		val &= ~(MUSB_RXCSR_DMAENAB
1874 			| MUSB_RXCSR_H_AUTOREQ
1875 			| MUSB_RXCSR_AUTOCLEAR
1876 			| MUSB_RXCSR_RXPKTRDY);
1877 		musb_writew(hw_ep->regs, MUSB_RXCSR, val);
1878 
1879 		if (musb_dma_inventra(musb) || musb_dma_ux500(musb) ||
1880 		    musb_dma_cppi41(musb)) {
1881 			    done = musb_rx_dma_inventra_cppi41(c, hw_ep, qh, urb, xfer_len);
1882 			    musb_dbg(hw_ep->musb,
1883 				    "ep %d dma %s, rxcsr %04x, rxcount %d",
1884 				    epnum, done ? "off" : "reset",
1885 				    musb_readw(epio, MUSB_RXCSR),
1886 				    musb_readw(epio, MUSB_RXCOUNT));
1887 		} else {
1888 			done = true;
1889 		}
1890 
1891 	} else if (urb->status == -EINPROGRESS) {
1892 		/* if no errors, be sure a packet is ready for unloading */
1893 		if (unlikely(!(rx_csr & MUSB_RXCSR_RXPKTRDY))) {
1894 			status = -EPROTO;
1895 			ERR("Rx interrupt with no errors or packet!\n");
1896 
1897 			/* FIXME this is another "SHOULD NEVER HAPPEN" */
1898 
1899 /* SCRUB (RX) */
1900 			/* do the proper sequence to abort the transfer */
1901 			musb_ep_select(mbase, epnum);
1902 			val &= ~MUSB_RXCSR_H_REQPKT;
1903 			musb_writew(epio, MUSB_RXCSR, val);
1904 			goto finish;
1905 		}
1906 
1907 		/* we are expecting IN packets */
1908 		if ((musb_dma_inventra(musb) || musb_dma_ux500(musb) ||
1909 		    musb_dma_cppi41(musb)) && dma) {
1910 			musb_dbg(hw_ep->musb,
1911 				"RX%d count %d, buffer 0x%llx len %d/%d",
1912 				epnum, musb_readw(epio, MUSB_RXCOUNT),
1913 				(unsigned long long) urb->transfer_dma
1914 				+ urb->actual_length,
1915 				qh->offset,
1916 				urb->transfer_buffer_length);
1917 
1918 			if (musb_rx_dma_in_inventra_cppi41(c, hw_ep, qh, urb,
1919 							   xfer_len, iso_err))
1920 				goto finish;
1921 			else
1922 				dev_err(musb->controller, "error: rx_dma failed\n");
1923 		}
1924 
1925 		if (!dma) {
1926 			unsigned int received_len;
1927 
1928 			/* Unmap the buffer so that CPU can use it */
1929 			usb_hcd_unmap_urb_for_dma(musb->hcd, urb);
1930 
1931 			/*
1932 			 * We need to map sg if the transfer_buffer is
1933 			 * NULL.
1934 			 */
1935 			if (!urb->transfer_buffer) {
1936 				qh->use_sg = true;
1937 				sg_miter_start(&qh->sg_miter, urb->sg, 1,
1938 						sg_flags);
1939 			}
1940 
1941 			if (qh->use_sg) {
1942 				if (!sg_miter_next(&qh->sg_miter)) {
1943 					dev_err(musb->controller, "error: sg list empty\n");
1944 					sg_miter_stop(&qh->sg_miter);
1945 					status = -EINVAL;
1946 					done = true;
1947 					goto finish;
1948 				}
1949 				urb->transfer_buffer = qh->sg_miter.addr;
1950 				received_len = urb->actual_length;
1951 				qh->offset = 0x0;
1952 				done = musb_host_packet_rx(musb, urb, epnum,
1953 						iso_err);
1954 				/* Calculate the number of bytes received */
1955 				received_len = urb->actual_length -
1956 					received_len;
1957 				qh->sg_miter.consumed = received_len;
1958 				sg_miter_stop(&qh->sg_miter);
1959 			} else {
1960 				done = musb_host_packet_rx(musb, urb,
1961 						epnum, iso_err);
1962 			}
1963 			musb_dbg(musb, "read %spacket", done ? "last " : "");
1964 		}
1965 	}
1966 
1967 finish:
1968 	urb->actual_length += xfer_len;
1969 	qh->offset += xfer_len;
1970 	if (done) {
1971 		if (qh->use_sg) {
1972 			qh->use_sg = false;
1973 			urb->transfer_buffer = NULL;
1974 		}
1975 
1976 		if (urb->status == -EINPROGRESS)
1977 			urb->status = status;
1978 		musb_advance_schedule(musb, urb, hw_ep, USB_DIR_IN);
1979 	}
1980 }
1981 
1982 /* schedule nodes correspond to peripheral endpoints, like an OHCI QH.
1983  * the software schedule associates multiple such nodes with a given
1984  * host side hardware endpoint + direction; scheduling may activate
1985  * that hardware endpoint.
1986  */
1987 static int musb_schedule(
1988 	struct musb		*musb,
1989 	struct musb_qh		*qh,
1990 	int			is_in)
1991 {
1992 	int			idle = 0;
1993 	int			best_diff;
1994 	int			best_end, epnum;
1995 	struct musb_hw_ep	*hw_ep = NULL;
1996 	struct list_head	*head = NULL;
1997 	u8			toggle;
1998 	u8			txtype;
1999 	struct urb		*urb = next_urb(qh);
2000 
2001 	/* use fixed hardware for control and bulk */
2002 	if (qh->type == USB_ENDPOINT_XFER_CONTROL) {
2003 		head = &musb->control;
2004 		hw_ep = musb->control_ep;
2005 		goto success;
2006 	}
2007 
2008 	/* else, periodic transfers get muxed to other endpoints */
2009 
2010 	/*
2011 	 * We know this qh hasn't been scheduled, so all we need to do
2012 	 * is choose which hardware endpoint to put it on ...
2013 	 *
2014 	 * REVISIT what we really want here is a regular schedule tree
2015 	 * like e.g. OHCI uses.
2016 	 */
2017 	best_diff = 4096;
2018 	best_end = -1;
2019 
2020 	for (epnum = 1, hw_ep = musb->endpoints + 1;
2021 			epnum < musb->nr_endpoints;
2022 			epnum++, hw_ep++) {
2023 		int	diff;
2024 
2025 		if (musb_ep_get_qh(hw_ep, is_in) != NULL)
2026 			continue;
2027 
2028 		if (hw_ep == musb->bulk_ep)
2029 			continue;
2030 
2031 		if (is_in)
2032 			diff = hw_ep->max_packet_sz_rx;
2033 		else
2034 			diff = hw_ep->max_packet_sz_tx;
2035 		diff -= (qh->maxpacket * qh->hb_mult);
2036 
2037 		if (diff >= 0 && best_diff > diff) {
2038 
2039 			/*
2040 			 * Mentor controller has a bug in that if we schedule
2041 			 * a BULK Tx transfer on an endpoint that had earlier
2042 			 * handled ISOC then the BULK transfer has to start on
2043 			 * a zero toggle.  If the BULK transfer starts on a 1
2044 			 * toggle then this transfer will fail as the mentor
2045 			 * controller starts the Bulk transfer on a 0 toggle
2046 			 * irrespective of the programming of the toggle bits
2047 			 * in the TXCSR register.  Check for this condition
2048 			 * while allocating the EP for a Tx Bulk transfer.  If
2049 			 * so skip this EP.
2050 			 */
2051 			hw_ep = musb->endpoints + epnum;
2052 			toggle = usb_gettoggle(urb->dev, qh->epnum, !is_in);
2053 			txtype = (musb_readb(hw_ep->regs, MUSB_TXTYPE)
2054 					>> 4) & 0x3;
2055 			if (!is_in && (qh->type == USB_ENDPOINT_XFER_BULK) &&
2056 				toggle && (txtype == USB_ENDPOINT_XFER_ISOC))
2057 				continue;
2058 
2059 			best_diff = diff;
2060 			best_end = epnum;
2061 		}
2062 	}
2063 	/* use bulk reserved ep1 if no other ep is free */
2064 	if (best_end < 0 && qh->type == USB_ENDPOINT_XFER_BULK) {
2065 		hw_ep = musb->bulk_ep;
2066 		if (is_in)
2067 			head = &musb->in_bulk;
2068 		else
2069 			head = &musb->out_bulk;
2070 
2071 		/* Enable bulk RX/TX NAK timeout scheme when bulk requests are
2072 		 * multiplexed. This scheme does not work in high speed to full
2073 		 * speed scenario as NAK interrupts are not coming from a
2074 		 * full speed device connected to a high speed device.
2075 		 * NAK timeout interval is 8 (128 uframe or 16ms) for HS and
2076 		 * 4 (8 frame or 8ms) for FS device.
2077 		 */
2078 		if (qh->dev)
2079 			qh->intv_reg =
2080 				(USB_SPEED_HIGH == qh->dev->speed) ? 8 : 4;
2081 		goto success;
2082 	} else if (best_end < 0) {
2083 		dev_err(musb->controller,
2084 				"%s hwep alloc failed for %dx%d\n",
2085 				musb_ep_xfertype_string(qh->type),
2086 				qh->hb_mult, qh->maxpacket);
2087 		return -ENOSPC;
2088 	}
2089 
2090 	idle = 1;
2091 	qh->mux = 0;
2092 	hw_ep = musb->endpoints + best_end;
2093 	musb_dbg(musb, "qh %p periodic slot %d", qh, best_end);
2094 success:
2095 	if (head) {
2096 		idle = list_empty(head);
2097 		list_add_tail(&qh->ring, head);
2098 		qh->mux = 1;
2099 	}
2100 	qh->hw_ep = hw_ep;
2101 	qh->hep->hcpriv = qh;
2102 	if (idle)
2103 		musb_start_urb(musb, is_in, qh);
2104 	return 0;
2105 }
2106 
2107 static int musb_urb_enqueue(
2108 	struct usb_hcd			*hcd,
2109 	struct urb			*urb,
2110 	gfp_t				mem_flags)
2111 {
2112 	unsigned long			flags;
2113 	struct musb			*musb = hcd_to_musb(hcd);
2114 	struct usb_host_endpoint	*hep = urb->ep;
2115 	struct musb_qh			*qh;
2116 	struct usb_endpoint_descriptor	*epd = &hep->desc;
2117 	int				ret;
2118 	unsigned			type_reg;
2119 	unsigned			interval;
2120 
2121 	/* host role must be active */
2122 	if (!is_host_active(musb) || !musb->is_active)
2123 		return -ENODEV;
2124 
2125 	trace_musb_urb_enq(musb, urb);
2126 
2127 	spin_lock_irqsave(&musb->lock, flags);
2128 	ret = usb_hcd_link_urb_to_ep(hcd, urb);
2129 	qh = ret ? NULL : hep->hcpriv;
2130 	if (qh)
2131 		urb->hcpriv = qh;
2132 	spin_unlock_irqrestore(&musb->lock, flags);
2133 
2134 	/* DMA mapping was already done, if needed, and this urb is on
2135 	 * hep->urb_list now ... so we're done, unless hep wasn't yet
2136 	 * scheduled onto a live qh.
2137 	 *
2138 	 * REVISIT best to keep hep->hcpriv valid until the endpoint gets
2139 	 * disabled, testing for empty qh->ring and avoiding qh setup costs
2140 	 * except for the first urb queued after a config change.
2141 	 */
2142 	if (qh || ret)
2143 		return ret;
2144 
2145 	/* Allocate and initialize qh, minimizing the work done each time
2146 	 * hw_ep gets reprogrammed, or with irqs blocked.  Then schedule it.
2147 	 *
2148 	 * REVISIT consider a dedicated qh kmem_cache, so it's harder
2149 	 * for bugs in other kernel code to break this driver...
2150 	 */
2151 	qh = kzalloc(sizeof *qh, mem_flags);
2152 	if (!qh) {
2153 		spin_lock_irqsave(&musb->lock, flags);
2154 		usb_hcd_unlink_urb_from_ep(hcd, urb);
2155 		spin_unlock_irqrestore(&musb->lock, flags);
2156 		return -ENOMEM;
2157 	}
2158 
2159 	qh->hep = hep;
2160 	qh->dev = urb->dev;
2161 	INIT_LIST_HEAD(&qh->ring);
2162 	qh->is_ready = 1;
2163 
2164 	qh->maxpacket = usb_endpoint_maxp(epd);
2165 	qh->type = usb_endpoint_type(epd);
2166 
2167 	/* Bits 11 & 12 of wMaxPacketSize encode high bandwidth multiplier.
2168 	 * Some musb cores don't support high bandwidth ISO transfers; and
2169 	 * we don't (yet!) support high bandwidth interrupt transfers.
2170 	 */
2171 	qh->hb_mult = usb_endpoint_maxp_mult(epd);
2172 	if (qh->hb_mult > 1) {
2173 		int ok = (qh->type == USB_ENDPOINT_XFER_ISOC);
2174 
2175 		if (ok)
2176 			ok = (usb_pipein(urb->pipe) && musb->hb_iso_rx)
2177 				|| (usb_pipeout(urb->pipe) && musb->hb_iso_tx);
2178 		if (!ok) {
2179 			dev_err(musb->controller,
2180 				"high bandwidth %s (%dx%d) not supported\n",
2181 				musb_ep_xfertype_string(qh->type),
2182 				qh->hb_mult, qh->maxpacket & 0x7ff);
2183 			ret = -EMSGSIZE;
2184 			goto done;
2185 		}
2186 		qh->maxpacket &= 0x7ff;
2187 	}
2188 
2189 	qh->epnum = usb_endpoint_num(epd);
2190 
2191 	/* NOTE: urb->dev->devnum is wrong during SET_ADDRESS */
2192 	qh->addr_reg = (u8) usb_pipedevice(urb->pipe);
2193 
2194 	/* precompute rxtype/txtype/type0 register */
2195 	type_reg = (qh->type << 4) | qh->epnum;
2196 	switch (urb->dev->speed) {
2197 	case USB_SPEED_LOW:
2198 		type_reg |= 0xc0;
2199 		break;
2200 	case USB_SPEED_FULL:
2201 		type_reg |= 0x80;
2202 		break;
2203 	default:
2204 		type_reg |= 0x40;
2205 	}
2206 	qh->type_reg = type_reg;
2207 
2208 	/* Precompute RXINTERVAL/TXINTERVAL register */
2209 	switch (qh->type) {
2210 	case USB_ENDPOINT_XFER_INT:
2211 		/*
2212 		 * Full/low speeds use the  linear encoding,
2213 		 * high speed uses the logarithmic encoding.
2214 		 */
2215 		if (urb->dev->speed <= USB_SPEED_FULL) {
2216 			interval = max_t(u8, epd->bInterval, 1);
2217 			break;
2218 		}
2219 		fallthrough;
2220 	case USB_ENDPOINT_XFER_ISOC:
2221 		/* ISO always uses logarithmic encoding */
2222 		interval = min_t(u8, epd->bInterval, 16);
2223 		break;
2224 	default:
2225 		/* REVISIT we actually want to use NAK limits, hinting to the
2226 		 * transfer scheduling logic to try some other qh, e.g. try
2227 		 * for 2 msec first:
2228 		 *
2229 		 * interval = (USB_SPEED_HIGH == urb->dev->speed) ? 16 : 2;
2230 		 *
2231 		 * The downside of disabling this is that transfer scheduling
2232 		 * gets VERY unfair for nonperiodic transfers; a misbehaving
2233 		 * peripheral could make that hurt.  That's perfectly normal
2234 		 * for reads from network or serial adapters ... so we have
2235 		 * partial NAKlimit support for bulk RX.
2236 		 *
2237 		 * The upside of disabling it is simpler transfer scheduling.
2238 		 */
2239 		interval = 0;
2240 	}
2241 	qh->intv_reg = interval;
2242 
2243 	/* precompute addressing for external hub/tt ports */
2244 	if (musb->is_multipoint) {
2245 		struct usb_device	*parent = urb->dev->parent;
2246 
2247 		if (parent != hcd->self.root_hub) {
2248 			qh->h_addr_reg = (u8) parent->devnum;
2249 
2250 			/* set up tt info if needed */
2251 			if (urb->dev->tt) {
2252 				qh->h_port_reg = (u8) urb->dev->ttport;
2253 				if (urb->dev->tt->hub)
2254 					qh->h_addr_reg =
2255 						(u8) urb->dev->tt->hub->devnum;
2256 				if (urb->dev->tt->multi)
2257 					qh->h_addr_reg |= 0x80;
2258 			}
2259 		}
2260 	}
2261 
2262 	/* invariant: hep->hcpriv is null OR the qh that's already scheduled.
2263 	 * until we get real dma queues (with an entry for each urb/buffer),
2264 	 * we only have work to do in the former case.
2265 	 */
2266 	spin_lock_irqsave(&musb->lock, flags);
2267 	if (hep->hcpriv || !next_urb(qh)) {
2268 		/* some concurrent activity submitted another urb to hep...
2269 		 * odd, rare, error prone, but legal.
2270 		 */
2271 		kfree(qh);
2272 		qh = NULL;
2273 		ret = 0;
2274 	} else
2275 		ret = musb_schedule(musb, qh,
2276 				epd->bEndpointAddress & USB_ENDPOINT_DIR_MASK);
2277 
2278 	if (ret == 0) {
2279 		urb->hcpriv = qh;
2280 		/* FIXME set urb->start_frame for iso/intr, it's tested in
2281 		 * musb_start_urb(), but otherwise only konicawc cares ...
2282 		 */
2283 	}
2284 	spin_unlock_irqrestore(&musb->lock, flags);
2285 
2286 done:
2287 	if (ret != 0) {
2288 		spin_lock_irqsave(&musb->lock, flags);
2289 		usb_hcd_unlink_urb_from_ep(hcd, urb);
2290 		spin_unlock_irqrestore(&musb->lock, flags);
2291 		kfree(qh);
2292 	}
2293 	return ret;
2294 }
2295 
2296 
2297 /*
2298  * abort a transfer that's at the head of a hardware queue.
2299  * called with controller locked, irqs blocked
2300  * that hardware queue advances to the next transfer, unless prevented
2301  */
2302 static int musb_cleanup_urb(struct urb *urb, struct musb_qh *qh)
2303 {
2304 	struct musb_hw_ep	*ep = qh->hw_ep;
2305 	struct musb		*musb = ep->musb;
2306 	void __iomem		*epio = ep->regs;
2307 	unsigned		hw_end = ep->epnum;
2308 	void __iomem		*regs = ep->musb->mregs;
2309 	int			is_in = usb_pipein(urb->pipe);
2310 	int			status = 0;
2311 	u16			csr;
2312 	struct dma_channel	*dma = NULL;
2313 
2314 	musb_ep_select(regs, hw_end);
2315 
2316 	if (is_dma_capable()) {
2317 		dma = is_in ? ep->rx_channel : ep->tx_channel;
2318 		if (dma) {
2319 			status = ep->musb->dma_controller->channel_abort(dma);
2320 			musb_dbg(musb, "abort %cX%d DMA for urb %p --> %d",
2321 				is_in ? 'R' : 'T', ep->epnum,
2322 				urb, status);
2323 			urb->actual_length += dma->actual_len;
2324 		}
2325 	}
2326 
2327 	/* turn off DMA requests, discard state, stop polling ... */
2328 	if (ep->epnum && is_in) {
2329 		/* giveback saves bulk toggle */
2330 		csr = musb_h_flush_rxfifo(ep, 0);
2331 
2332 		/* clear the endpoint's irq status here to avoid bogus irqs */
2333 		if (is_dma_capable() && dma)
2334 			musb_platform_clear_ep_rxintr(musb, ep->epnum);
2335 	} else if (ep->epnum) {
2336 		musb_h_tx_flush_fifo(ep);
2337 		csr = musb_readw(epio, MUSB_TXCSR);
2338 		csr &= ~(MUSB_TXCSR_AUTOSET
2339 			| MUSB_TXCSR_DMAENAB
2340 			| MUSB_TXCSR_H_RXSTALL
2341 			| MUSB_TXCSR_H_NAKTIMEOUT
2342 			| MUSB_TXCSR_H_ERROR
2343 			| MUSB_TXCSR_TXPKTRDY);
2344 		musb_writew(epio, MUSB_TXCSR, csr);
2345 		/* REVISIT may need to clear FLUSHFIFO ... */
2346 		musb_writew(epio, MUSB_TXCSR, csr);
2347 		/* flush cpu writebuffer */
2348 		csr = musb_readw(epio, MUSB_TXCSR);
2349 	} else  {
2350 		musb_h_ep0_flush_fifo(ep);
2351 	}
2352 	if (status == 0)
2353 		musb_advance_schedule(ep->musb, urb, ep, is_in);
2354 	return status;
2355 }
2356 
2357 static int musb_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
2358 {
2359 	struct musb		*musb = hcd_to_musb(hcd);
2360 	struct musb_qh		*qh;
2361 	unsigned long		flags;
2362 	int			is_in  = usb_pipein(urb->pipe);
2363 	int			ret;
2364 
2365 	trace_musb_urb_deq(musb, urb);
2366 
2367 	spin_lock_irqsave(&musb->lock, flags);
2368 	ret = usb_hcd_check_unlink_urb(hcd, urb, status);
2369 	if (ret)
2370 		goto done;
2371 
2372 	qh = urb->hcpriv;
2373 	if (!qh)
2374 		goto done;
2375 
2376 	/*
2377 	 * Any URB not actively programmed into endpoint hardware can be
2378 	 * immediately given back; that's any URB not at the head of an
2379 	 * endpoint queue, unless someday we get real DMA queues.  And even
2380 	 * if it's at the head, it might not be known to the hardware...
2381 	 *
2382 	 * Otherwise abort current transfer, pending DMA, etc.; urb->status
2383 	 * has already been updated.  This is a synchronous abort; it'd be
2384 	 * OK to hold off until after some IRQ, though.
2385 	 *
2386 	 * NOTE: qh is invalid unless !list_empty(&hep->urb_list)
2387 	 */
2388 	if (!qh->is_ready
2389 			|| urb->urb_list.prev != &qh->hep->urb_list
2390 			|| musb_ep_get_qh(qh->hw_ep, is_in) != qh) {
2391 		int	ready = qh->is_ready;
2392 
2393 		qh->is_ready = 0;
2394 		musb_giveback(musb, urb, 0);
2395 		qh->is_ready = ready;
2396 
2397 		/* If nothing else (usually musb_giveback) is using it
2398 		 * and its URB list has emptied, recycle this qh.
2399 		 */
2400 		if (ready && list_empty(&qh->hep->urb_list)) {
2401 			qh->hep->hcpriv = NULL;
2402 			list_del(&qh->ring);
2403 			kfree(qh);
2404 		}
2405 	} else
2406 		ret = musb_cleanup_urb(urb, qh);
2407 done:
2408 	spin_unlock_irqrestore(&musb->lock, flags);
2409 	return ret;
2410 }
2411 
2412 /* disable an endpoint */
2413 static void
2414 musb_h_disable(struct usb_hcd *hcd, struct usb_host_endpoint *hep)
2415 {
2416 	u8			is_in = hep->desc.bEndpointAddress & USB_DIR_IN;
2417 	unsigned long		flags;
2418 	struct musb		*musb = hcd_to_musb(hcd);
2419 	struct musb_qh		*qh;
2420 	struct urb		*urb;
2421 
2422 	spin_lock_irqsave(&musb->lock, flags);
2423 
2424 	qh = hep->hcpriv;
2425 	if (qh == NULL)
2426 		goto exit;
2427 
2428 	/* NOTE: qh is invalid unless !list_empty(&hep->urb_list) */
2429 
2430 	/* Kick the first URB off the hardware, if needed */
2431 	qh->is_ready = 0;
2432 	if (musb_ep_get_qh(qh->hw_ep, is_in) == qh) {
2433 		urb = next_urb(qh);
2434 
2435 		/* make software (then hardware) stop ASAP */
2436 		if (!urb->unlinked)
2437 			urb->status = -ESHUTDOWN;
2438 
2439 		/* cleanup */
2440 		musb_cleanup_urb(urb, qh);
2441 
2442 		/* Then nuke all the others ... and advance the
2443 		 * queue on hw_ep (e.g. bulk ring) when we're done.
2444 		 */
2445 		while (!list_empty(&hep->urb_list)) {
2446 			urb = next_urb(qh);
2447 			urb->status = -ESHUTDOWN;
2448 			musb_advance_schedule(musb, urb, qh->hw_ep, is_in);
2449 		}
2450 	} else {
2451 		/* Just empty the queue; the hardware is busy with
2452 		 * other transfers, and since !qh->is_ready nothing
2453 		 * will activate any of these as it advances.
2454 		 */
2455 		while (!list_empty(&hep->urb_list))
2456 			musb_giveback(musb, next_urb(qh), -ESHUTDOWN);
2457 
2458 		hep->hcpriv = NULL;
2459 		list_del(&qh->ring);
2460 		kfree(qh);
2461 	}
2462 exit:
2463 	spin_unlock_irqrestore(&musb->lock, flags);
2464 }
2465 
2466 static int musb_h_get_frame_number(struct usb_hcd *hcd)
2467 {
2468 	struct musb	*musb = hcd_to_musb(hcd);
2469 
2470 	return musb_readw(musb->mregs, MUSB_FRAME);
2471 }
2472 
2473 static int musb_h_start(struct usb_hcd *hcd)
2474 {
2475 	struct musb	*musb = hcd_to_musb(hcd);
2476 
2477 	/* NOTE: musb_start() is called when the hub driver turns
2478 	 * on port power, or when (OTG) peripheral starts.
2479 	 */
2480 	hcd->state = HC_STATE_RUNNING;
2481 	musb->port1_status = 0;
2482 	return 0;
2483 }
2484 
2485 static void musb_h_stop(struct usb_hcd *hcd)
2486 {
2487 	musb_stop(hcd_to_musb(hcd));
2488 	hcd->state = HC_STATE_HALT;
2489 }
2490 
2491 static int musb_bus_suspend(struct usb_hcd *hcd)
2492 {
2493 	struct musb	*musb = hcd_to_musb(hcd);
2494 	u8		devctl;
2495 	int		ret;
2496 
2497 	ret = musb_port_suspend(musb, true);
2498 	if (ret)
2499 		return ret;
2500 
2501 	if (!is_host_active(musb))
2502 		return 0;
2503 
2504 	switch (musb_get_state(musb)) {
2505 	case OTG_STATE_A_SUSPEND:
2506 		return 0;
2507 	case OTG_STATE_A_WAIT_VRISE:
2508 		/* ID could be grounded even if there's no device
2509 		 * on the other end of the cable.  NOTE that the
2510 		 * A_WAIT_VRISE timers are messy with MUSB...
2511 		 */
2512 		devctl = musb_readb(musb->mregs, MUSB_DEVCTL);
2513 		if ((devctl & MUSB_DEVCTL_VBUS) == MUSB_DEVCTL_VBUS)
2514 			musb_set_state(musb, OTG_STATE_A_WAIT_BCON);
2515 		break;
2516 	default:
2517 		break;
2518 	}
2519 
2520 	if (musb->is_active) {
2521 		WARNING("trying to suspend as %s while active\n",
2522 			musb_otg_state_string(musb));
2523 		return -EBUSY;
2524 	} else
2525 		return 0;
2526 }
2527 
2528 static int musb_bus_resume(struct usb_hcd *hcd)
2529 {
2530 	struct musb *musb = hcd_to_musb(hcd);
2531 
2532 	if (musb->config &&
2533 	    musb->config->host_port_deassert_reset_at_resume)
2534 		musb_port_reset(musb, false);
2535 
2536 	return 0;
2537 }
2538 
2539 #ifndef CONFIG_MUSB_PIO_ONLY
2540 
2541 #define MUSB_USB_DMA_ALIGN 4
2542 
2543 struct musb_temp_buffer {
2544 	void *kmalloc_ptr;
2545 	void *old_xfer_buffer;
2546 	u8 data[];
2547 };
2548 
2549 static void musb_free_temp_buffer(struct urb *urb)
2550 {
2551 	enum dma_data_direction dir;
2552 	struct musb_temp_buffer *temp;
2553 	size_t length;
2554 
2555 	if (!(urb->transfer_flags & URB_ALIGNED_TEMP_BUFFER))
2556 		return;
2557 
2558 	dir = usb_urb_dir_in(urb) ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
2559 
2560 	temp = container_of(urb->transfer_buffer, struct musb_temp_buffer,
2561 			    data);
2562 
2563 	if (dir == DMA_FROM_DEVICE) {
2564 		if (usb_pipeisoc(urb->pipe))
2565 			length = urb->transfer_buffer_length;
2566 		else
2567 			length = urb->actual_length;
2568 
2569 		memcpy(temp->old_xfer_buffer, temp->data, length);
2570 	}
2571 	urb->transfer_buffer = temp->old_xfer_buffer;
2572 	kfree(temp->kmalloc_ptr);
2573 
2574 	urb->transfer_flags &= ~URB_ALIGNED_TEMP_BUFFER;
2575 }
2576 
2577 static int musb_alloc_temp_buffer(struct urb *urb, gfp_t mem_flags)
2578 {
2579 	enum dma_data_direction dir;
2580 	struct musb_temp_buffer *temp;
2581 	void *kmalloc_ptr;
2582 	size_t kmalloc_size;
2583 
2584 	if (urb->num_sgs || urb->sg ||
2585 	    urb->transfer_buffer_length == 0 ||
2586 	    !((uintptr_t)urb->transfer_buffer & (MUSB_USB_DMA_ALIGN - 1)))
2587 		return 0;
2588 
2589 	dir = usb_urb_dir_in(urb) ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
2590 
2591 	/* Allocate a buffer with enough padding for alignment */
2592 	kmalloc_size = urb->transfer_buffer_length +
2593 		sizeof(struct musb_temp_buffer) + MUSB_USB_DMA_ALIGN - 1;
2594 
2595 	kmalloc_ptr = kmalloc(kmalloc_size, mem_flags);
2596 	if (!kmalloc_ptr)
2597 		return -ENOMEM;
2598 
2599 	/* Position our struct temp_buffer such that data is aligned */
2600 	temp = PTR_ALIGN(kmalloc_ptr, MUSB_USB_DMA_ALIGN);
2601 
2602 
2603 	temp->kmalloc_ptr = kmalloc_ptr;
2604 	temp->old_xfer_buffer = urb->transfer_buffer;
2605 	if (dir == DMA_TO_DEVICE)
2606 		memcpy(temp->data, urb->transfer_buffer,
2607 		       urb->transfer_buffer_length);
2608 	urb->transfer_buffer = temp->data;
2609 
2610 	urb->transfer_flags |= URB_ALIGNED_TEMP_BUFFER;
2611 
2612 	return 0;
2613 }
2614 
2615 static int musb_map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb,
2616 				      gfp_t mem_flags)
2617 {
2618 	struct musb	*musb = hcd_to_musb(hcd);
2619 	int ret;
2620 
2621 	/*
2622 	 * The DMA engine in RTL1.8 and above cannot handle
2623 	 * DMA addresses that are not aligned to a 4 byte boundary.
2624 	 * For such engine implemented (un)map_urb_for_dma hooks.
2625 	 * Do not use these hooks for RTL<1.8
2626 	 */
2627 	if (musb->hwvers < MUSB_HWVERS_1800)
2628 		return usb_hcd_map_urb_for_dma(hcd, urb, mem_flags);
2629 
2630 	ret = musb_alloc_temp_buffer(urb, mem_flags);
2631 	if (ret)
2632 		return ret;
2633 
2634 	ret = usb_hcd_map_urb_for_dma(hcd, urb, mem_flags);
2635 	if (ret)
2636 		musb_free_temp_buffer(urb);
2637 
2638 	return ret;
2639 }
2640 
2641 static void musb_unmap_urb_for_dma(struct usb_hcd *hcd, struct urb *urb)
2642 {
2643 	struct musb	*musb = hcd_to_musb(hcd);
2644 
2645 	usb_hcd_unmap_urb_for_dma(hcd, urb);
2646 
2647 	/* Do not use this hook for RTL<1.8 (see description above) */
2648 	if (musb->hwvers < MUSB_HWVERS_1800)
2649 		return;
2650 
2651 	musb_free_temp_buffer(urb);
2652 }
2653 #endif /* !CONFIG_MUSB_PIO_ONLY */
2654 
2655 static const struct hc_driver musb_hc_driver = {
2656 	.description		= "musb-hcd",
2657 	.product_desc		= "MUSB HDRC host driver",
2658 	.hcd_priv_size		= sizeof(struct musb *),
2659 	.flags			= HCD_USB2 | HCD_DMA | HCD_MEMORY,
2660 
2661 	/* not using irq handler or reset hooks from usbcore, since
2662 	 * those must be shared with peripheral code for OTG configs
2663 	 */
2664 
2665 	.start			= musb_h_start,
2666 	.stop			= musb_h_stop,
2667 
2668 	.get_frame_number	= musb_h_get_frame_number,
2669 
2670 	.urb_enqueue		= musb_urb_enqueue,
2671 	.urb_dequeue		= musb_urb_dequeue,
2672 	.endpoint_disable	= musb_h_disable,
2673 
2674 #ifndef CONFIG_MUSB_PIO_ONLY
2675 	.map_urb_for_dma	= musb_map_urb_for_dma,
2676 	.unmap_urb_for_dma	= musb_unmap_urb_for_dma,
2677 #endif
2678 
2679 	.hub_status_data	= musb_hub_status_data,
2680 	.hub_control		= musb_hub_control,
2681 	.bus_suspend		= musb_bus_suspend,
2682 	.bus_resume		= musb_bus_resume,
2683 	/* .start_port_reset	= NULL, */
2684 	/* .hub_irq_enable	= NULL, */
2685 };
2686 
2687 int musb_host_alloc(struct musb *musb)
2688 {
2689 	struct device	*dev = musb->controller;
2690 
2691 	/* usbcore sets dev->driver_data to hcd, and sometimes uses that... */
2692 	musb->hcd = usb_create_hcd(&musb_hc_driver, dev, dev_name(dev));
2693 	if (!musb->hcd)
2694 		return -EINVAL;
2695 
2696 	*musb->hcd->hcd_priv = (unsigned long) musb;
2697 	musb->hcd->self.uses_pio_for_control = 1;
2698 	musb->hcd->uses_new_polling = 1;
2699 	musb->hcd->has_tt = 1;
2700 
2701 	return 0;
2702 }
2703 
2704 void musb_host_cleanup(struct musb *musb)
2705 {
2706 	if (musb->port_mode == MUSB_PERIPHERAL)
2707 		return;
2708 	usb_remove_hcd(musb->hcd);
2709 }
2710 
2711 void musb_host_free(struct musb *musb)
2712 {
2713 	usb_put_hcd(musb->hcd);
2714 }
2715 
2716 int musb_host_setup(struct musb *musb, int power_budget)
2717 {
2718 	int ret;
2719 	struct usb_hcd *hcd = musb->hcd;
2720 
2721 	if (musb->port_mode == MUSB_HOST) {
2722 		MUSB_HST_MODE(musb);
2723 		musb_set_state(musb, OTG_STATE_A_IDLE);
2724 	}
2725 
2726 	if (musb->xceiv) {
2727 		otg_set_host(musb->xceiv->otg, &hcd->self);
2728 		musb->xceiv->otg->host = &hcd->self;
2729 	} else {
2730 		phy_set_mode(musb->phy, PHY_MODE_USB_HOST);
2731 	}
2732 
2733 	/* don't support otg protocols */
2734 	hcd->self.otg_port = 0;
2735 	hcd->power_budget = 2 * (power_budget ? : 250);
2736 	hcd->skip_phy_initialization = 1;
2737 
2738 	ret = usb_add_hcd(hcd, 0, 0);
2739 	if (ret < 0)
2740 		return ret;
2741 
2742 	device_wakeup_enable(hcd->self.controller);
2743 	return 0;
2744 }
2745 
2746 void musb_host_resume_root_hub(struct musb *musb)
2747 {
2748 	usb_hcd_resume_root_hub(musb->hcd);
2749 }
2750 
2751 void musb_host_poke_root_hub(struct musb *musb)
2752 {
2753 	MUSB_HST_MODE(musb);
2754 	if (musb->hcd->status_urb)
2755 		usb_hcd_poll_rh_status(musb->hcd);
2756 	else
2757 		usb_hcd_resume_root_hub(musb->hcd);
2758 }
2759