xref: /linux/drivers/usb/dwc2/hcd_queue.c (revision e58e871becec2d3b04ed91c0c16fe8deac9c9dfa)
1 /*
2  * hcd_queue.c - DesignWare HS OTG Controller host queuing routines
3  *
4  * Copyright (C) 2004-2013 Synopsys, Inc.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions, and the following disclaimer,
11  *    without modification.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. The names of the above-listed copyright holders may not be used
16  *    to endorse or promote products derived from this software without
17  *    specific prior written permission.
18  *
19  * ALTERNATIVELY, this software may be distributed under the terms of the
20  * GNU General Public License ("GPL") as published by the Free Software
21  * Foundation; either version 2 of the License, or (at your option) any
22  * later version.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
25  * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
26  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
27  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
28  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
29  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
30  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
31  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
32  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
33  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
34  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
35  */
36 
37 /*
38  * This file contains the functions to manage Queue Heads and Queue
39  * Transfer Descriptors for Host mode
40  */
41 #include <linux/gcd.h>
42 #include <linux/kernel.h>
43 #include <linux/module.h>
44 #include <linux/spinlock.h>
45 #include <linux/interrupt.h>
46 #include <linux/dma-mapping.h>
47 #include <linux/io.h>
48 #include <linux/slab.h>
49 #include <linux/usb.h>
50 
51 #include <linux/usb/hcd.h>
52 #include <linux/usb/ch11.h>
53 
54 #include "core.h"
55 #include "hcd.h"
56 
57 /* Wait this long before releasing periodic reservation */
58 #define DWC2_UNRESERVE_DELAY (msecs_to_jiffies(5))
59 
60 /**
61  * dwc2_periodic_channel_available() - Checks that a channel is available for a
62  * periodic transfer
63  *
64  * @hsotg: The HCD state structure for the DWC OTG controller
65  *
66  * Return: 0 if successful, negative error code otherwise
67  */
68 static int dwc2_periodic_channel_available(struct dwc2_hsotg *hsotg)
69 {
70 	/*
71 	 * Currently assuming that there is a dedicated host channel for
72 	 * each periodic transaction plus at least one host channel for
73 	 * non-periodic transactions
74 	 */
75 	int status;
76 	int num_channels;
77 
78 	num_channels = hsotg->params.host_channels;
79 	if ((hsotg->periodic_channels + hsotg->non_periodic_channels <
80 	     num_channels) && (hsotg->periodic_channels < num_channels - 1)) {
81 		status = 0;
82 	} else {
83 		dev_dbg(hsotg->dev,
84 			"%s: Total channels: %d, Periodic: %d, Non-periodic: %d\n",
85 			__func__, num_channels,
86 			hsotg->periodic_channels, hsotg->non_periodic_channels);
87 		status = -ENOSPC;
88 	}
89 
90 	return status;
91 }
92 
93 /**
94  * dwc2_check_periodic_bandwidth() - Checks that there is sufficient bandwidth
95  * for the specified QH in the periodic schedule
96  *
97  * @hsotg: The HCD state structure for the DWC OTG controller
98  * @qh:    QH containing periodic bandwidth required
99  *
100  * Return: 0 if successful, negative error code otherwise
101  *
102  * For simplicity, this calculation assumes that all the transfers in the
103  * periodic schedule may occur in the same (micro)frame
104  */
105 static int dwc2_check_periodic_bandwidth(struct dwc2_hsotg *hsotg,
106 					 struct dwc2_qh *qh)
107 {
108 	int status;
109 	s16 max_claimed_usecs;
110 
111 	status = 0;
112 
113 	if (qh->dev_speed == USB_SPEED_HIGH || qh->do_split) {
114 		/*
115 		 * High speed mode
116 		 * Max periodic usecs is 80% x 125 usec = 100 usec
117 		 */
118 		max_claimed_usecs = 100 - qh->host_us;
119 	} else {
120 		/*
121 		 * Full speed mode
122 		 * Max periodic usecs is 90% x 1000 usec = 900 usec
123 		 */
124 		max_claimed_usecs = 900 - qh->host_us;
125 	}
126 
127 	if (hsotg->periodic_usecs > max_claimed_usecs) {
128 		dev_err(hsotg->dev,
129 			"%s: already claimed usecs %d, required usecs %d\n",
130 			__func__, hsotg->periodic_usecs, qh->host_us);
131 		status = -ENOSPC;
132 	}
133 
134 	return status;
135 }
136 
137 /**
138  * pmap_schedule() - Schedule time in a periodic bitmap (pmap).
139  *
140  * @map:             The bitmap representing the schedule; will be updated
141  *                   upon success.
142  * @bits_per_period: The schedule represents several periods.  This is how many
143  *                   bits are in each period.  It's assumed that the beginning
144  *                   of the schedule will repeat after its end.
145  * @periods_in_map:  The number of periods in the schedule.
146  * @num_bits:        The number of bits we need per period we want to reserve
147  *                   in this function call.
148  * @interval:        How often we need to be scheduled for the reservation this
149  *                   time.  1 means every period.  2 means every other period.
150  *                   ...you get the picture?
151  * @start:           The bit number to start at.  Normally 0.  Must be within
152  *                   the interval or we return failure right away.
153  * @only_one_period: Normally we'll allow picking a start anywhere within the
154  *                   first interval, since we can still make all repetition
155  *                   requirements by doing that.  However, if you pass true
156  *                   here then we'll return failure if we can't fit within
157  *                   the period that "start" is in.
158  *
159  * The idea here is that we want to schedule time for repeating events that all
160  * want the same resource.  The resource is divided into fixed-sized periods
161  * and the events want to repeat every "interval" periods.  The schedule
162  * granularity is one bit.
163  *
164  * To keep things "simple", we'll represent our schedule with a bitmap that
165  * contains a fixed number of periods.  This gets rid of a lot of complexity
166  * but does mean that we need to handle things specially (and non-ideally) if
167  * the number of the periods in the schedule doesn't match well with the
168  * intervals that we're trying to schedule.
169  *
170  * Here's an explanation of the scheme we'll implement, assuming 8 periods.
171  * - If interval is 1, we need to take up space in each of the 8
172  *   periods we're scheduling.  Easy.
173  * - If interval is 2, we need to take up space in half of the
174  *   periods.  Again, easy.
175  * - If interval is 3, we actually need to fall back to interval 1.
176  *   Why?  Because we might need time in any period.  AKA for the
177  *   first 8 periods, we'll be in slot 0, 3, 6.  Then we'll be
178  *   in slot 1, 4, 7.  Then we'll be in 2, 5.  Then we'll be back to
179  *   0, 3, and 6.  Since we could be in any frame we need to reserve
180  *   for all of them.  Sucks, but that's what you gotta do.  Note that
181  *   if we were instead scheduling 8 * 3 = 24 we'd do much better, but
182  *   then we need more memory and time to do scheduling.
183  * - If interval is 4, easy.
184  * - If interval is 5, we again need interval 1.  The schedule will be
185  *   0, 5, 2, 7, 4, 1, 6, 3, 0
186  * - If interval is 6, we need interval 2.  0, 6, 4, 2.
187  * - If interval is 7, we need interval 1.
188  * - If interval is 8, we need interval 8.
189  *
190  * If you do the math, you'll see that we need to pretend that interval is
191  * equal to the greatest_common_divisor(interval, periods_in_map).
192  *
193  * Note that at the moment this function tends to front-pack the schedule.
194  * In some cases that's really non-ideal (it's hard to schedule things that
195  * need to repeat every period).  In other cases it's perfect (you can easily
196  * schedule bigger, less often repeating things).
197  *
198  * Here's the algorithm in action (8 periods, 5 bits per period):
199  *  |**   |     |**   |     |**   |     |**   |     |   OK 2 bits, intv 2 at 0
200  *  |*****|  ***|*****|  ***|*****|  ***|*****|  ***|   OK 3 bits, intv 3 at 2
201  *  |*****|* ***|*****|  ***|*****|* ***|*****|  ***|   OK 1 bits, intv 4 at 5
202  *  |**   |*    |**   |     |**   |*    |**   |     | Remv 3 bits, intv 3 at 2
203  *  |***  |*    |***  |     |***  |*    |***  |     |   OK 1 bits, intv 6 at 2
204  *  |**** |*  * |**** |   * |**** |*  * |**** |   * |   OK 1 bits, intv 1 at 3
205  *  |**** |**** |**** | *** |**** |**** |**** | *** |   OK 2 bits, intv 2 at 6
206  *  |*****|*****|*****| ****|*****|*****|*****| ****|   OK 1 bits, intv 1 at 4
207  *  |*****|*****|*****| ****|*****|*****|*****| ****| FAIL 1 bits, intv 1
208  *  |  ***|*****|  ***| ****|  ***|*****|  ***| ****| Remv 2 bits, intv 2 at 0
209  *  |  ***| ****|  ***| ****|  ***| ****|  ***| ****| Remv 1 bits, intv 4 at 5
210  *  |   **| ****|   **| ****|   **| ****|   **| ****| Remv 1 bits, intv 6 at 2
211  *  |    *| ** *|    *| ** *|    *| ** *|    *| ** *| Remv 1 bits, intv 1 at 3
212  *  |    *|    *|    *|    *|    *|    *|    *|    *| Remv 2 bits, intv 2 at 6
213  *  |     |     |     |     |     |     |     |     | Remv 1 bits, intv 1 at 4
214  *  |**   |     |**   |     |**   |     |**   |     |   OK 2 bits, intv 2 at 0
215  *  |***  |     |**   |     |***  |     |**   |     |   OK 1 bits, intv 4 at 2
216  *  |*****|     |** **|     |*****|     |** **|     |   OK 2 bits, intv 2 at 3
217  *  |*****|*    |** **|     |*****|*    |** **|     |   OK 1 bits, intv 4 at 5
218  *  |*****|***  |** **| **  |*****|***  |** **| **  |   OK 2 bits, intv 2 at 6
219  *  |*****|*****|** **| ****|*****|*****|** **| ****|   OK 2 bits, intv 2 at 8
220  *  |*****|*****|*****| ****|*****|*****|*****| ****|   OK 1 bits, intv 4 at 12
221  *
222  * This function is pretty generic and could be easily abstracted if anything
223  * needed similar scheduling.
224  *
225  * Returns either -ENOSPC or a >= 0 start bit which should be passed to the
226  * unschedule routine.  The map bitmap will be updated on a non-error result.
227  */
228 static int pmap_schedule(unsigned long *map, int bits_per_period,
229 			 int periods_in_map, int num_bits,
230 			 int interval, int start, bool only_one_period)
231 {
232 	int interval_bits;
233 	int to_reserve;
234 	int first_end;
235 	int i;
236 
237 	if (num_bits > bits_per_period)
238 		return -ENOSPC;
239 
240 	/* Adjust interval as per description */
241 	interval = gcd(interval, periods_in_map);
242 
243 	interval_bits = bits_per_period * interval;
244 	to_reserve = periods_in_map / interval;
245 
246 	/* If start has gotten us past interval then we can't schedule */
247 	if (start >= interval_bits)
248 		return -ENOSPC;
249 
250 	if (only_one_period)
251 		/* Must fit within same period as start; end at begin of next */
252 		first_end = (start / bits_per_period + 1) * bits_per_period;
253 	else
254 		/* Can fit anywhere in the first interval */
255 		first_end = interval_bits;
256 
257 	/*
258 	 * We'll try to pick the first repetition, then see if that time
259 	 * is free for each of the subsequent repetitions.  If it's not
260 	 * we'll adjust the start time for the next search of the first
261 	 * repetition.
262 	 */
263 	while (start + num_bits <= first_end) {
264 		int end;
265 
266 		/* Need to stay within this period */
267 		end = (start / bits_per_period + 1) * bits_per_period;
268 
269 		/* Look for num_bits us in this microframe starting at start */
270 		start = bitmap_find_next_zero_area(map, end, start, num_bits,
271 						   0);
272 
273 		/*
274 		 * We should get start >= end if we fail.  We might be
275 		 * able to check the next microframe depending on the
276 		 * interval, so continue on (start already updated).
277 		 */
278 		if (start >= end) {
279 			start = end;
280 			continue;
281 		}
282 
283 		/* At this point we have a valid point for first one */
284 		for (i = 1; i < to_reserve; i++) {
285 			int ith_start = start + interval_bits * i;
286 			int ith_end = end + interval_bits * i;
287 			int ret;
288 
289 			/* Use this as a dumb "check if bits are 0" */
290 			ret = bitmap_find_next_zero_area(
291 				map, ith_start + num_bits, ith_start, num_bits,
292 				0);
293 
294 			/* We got the right place, continue checking */
295 			if (ret == ith_start)
296 				continue;
297 
298 			/* Move start up for next time and exit for loop */
299 			ith_start = bitmap_find_next_zero_area(
300 				map, ith_end, ith_start, num_bits, 0);
301 			if (ith_start >= ith_end)
302 				/* Need a while new period next time */
303 				start = end;
304 			else
305 				start = ith_start - interval_bits * i;
306 			break;
307 		}
308 
309 		/* If didn't exit the for loop with a break, we have success */
310 		if (i == to_reserve)
311 			break;
312 	}
313 
314 	if (start + num_bits > first_end)
315 		return -ENOSPC;
316 
317 	for (i = 0; i < to_reserve; i++) {
318 		int ith_start = start + interval_bits * i;
319 
320 		bitmap_set(map, ith_start, num_bits);
321 	}
322 
323 	return start;
324 }
325 
326 /**
327  * pmap_unschedule() - Undo work done by pmap_schedule()
328  *
329  * @map:             See pmap_schedule().
330  * @bits_per_period: See pmap_schedule().
331  * @periods_in_map:  See pmap_schedule().
332  * @num_bits:        The number of bits that was passed to schedule.
333  * @interval:        The interval that was passed to schedule.
334  * @start:           The return value from pmap_schedule().
335  */
336 static void pmap_unschedule(unsigned long *map, int bits_per_period,
337 			    int periods_in_map, int num_bits,
338 			    int interval, int start)
339 {
340 	int interval_bits;
341 	int to_release;
342 	int i;
343 
344 	/* Adjust interval as per description in pmap_schedule() */
345 	interval = gcd(interval, periods_in_map);
346 
347 	interval_bits = bits_per_period * interval;
348 	to_release = periods_in_map / interval;
349 
350 	for (i = 0; i < to_release; i++) {
351 		int ith_start = start + interval_bits * i;
352 
353 		bitmap_clear(map, ith_start, num_bits);
354 	}
355 }
356 
357 /**
358  * dwc2_get_ls_map() - Get the map used for the given qh
359  *
360  * @hsotg: The HCD state structure for the DWC OTG controller.
361  * @qh:    QH for the periodic transfer.
362  *
363  * We'll always get the periodic map out of our TT.  Note that even if we're
364  * running the host straight in low speed / full speed mode it appears as if
365  * a TT is allocated for us, so we'll use it.  If that ever changes we can
366  * add logic here to get a map out of "hsotg" if !qh->do_split.
367  *
368  * Returns: the map or NULL if a map couldn't be found.
369  */
370 static unsigned long *dwc2_get_ls_map(struct dwc2_hsotg *hsotg,
371 				      struct dwc2_qh *qh)
372 {
373 	unsigned long *map;
374 
375 	/* Don't expect to be missing a TT and be doing low speed scheduling */
376 	if (WARN_ON(!qh->dwc_tt))
377 		return NULL;
378 
379 	/* Get the map and adjust if this is a multi_tt hub */
380 	map = qh->dwc_tt->periodic_bitmaps;
381 	if (qh->dwc_tt->usb_tt->multi)
382 		map += DWC2_ELEMENTS_PER_LS_BITMAP * qh->ttport;
383 
384 	return map;
385 }
386 
387 #ifdef DWC2_PRINT_SCHEDULE
388 /*
389  * cat_printf() - A printf() + strcat() helper
390  *
391  * This is useful for concatenating a bunch of strings where each string is
392  * constructed using printf.
393  *
394  * @buf:   The destination buffer; will be updated to point after the printed
395  *         data.
396  * @size:  The number of bytes in the buffer (includes space for '\0').
397  * @fmt:   The format for printf.
398  * @...:   The args for printf.
399  */
400 static __printf(3, 4)
401 void cat_printf(char **buf, size_t *size, const char *fmt, ...)
402 {
403 	va_list args;
404 	int i;
405 
406 	if (*size == 0)
407 		return;
408 
409 	va_start(args, fmt);
410 	i = vsnprintf(*buf, *size, fmt, args);
411 	va_end(args);
412 
413 	if (i >= *size) {
414 		(*buf)[*size - 1] = '\0';
415 		*buf += *size;
416 		*size = 0;
417 	} else {
418 		*buf += i;
419 		*size -= i;
420 	}
421 }
422 
423 /*
424  * pmap_print() - Print the given periodic map
425  *
426  * Will attempt to print out the periodic schedule.
427  *
428  * @map:             See pmap_schedule().
429  * @bits_per_period: See pmap_schedule().
430  * @periods_in_map:  See pmap_schedule().
431  * @period_name:     The name of 1 period, like "uFrame"
432  * @units:           The name of the units, like "us".
433  * @print_fn:        The function to call for printing.
434  * @print_data:      Opaque data to pass to the print function.
435  */
436 static void pmap_print(unsigned long *map, int bits_per_period,
437 		       int periods_in_map, const char *period_name,
438 		       const char *units,
439 		       void (*print_fn)(const char *str, void *data),
440 		       void *print_data)
441 {
442 	int period;
443 
444 	for (period = 0; period < periods_in_map; period++) {
445 		char tmp[64];
446 		char *buf = tmp;
447 		size_t buf_size = sizeof(tmp);
448 		int period_start = period * bits_per_period;
449 		int period_end = period_start + bits_per_period;
450 		int start = 0;
451 		int count = 0;
452 		bool printed = false;
453 		int i;
454 
455 		for (i = period_start; i < period_end + 1; i++) {
456 			/* Handle case when ith bit is set */
457 			if (i < period_end &&
458 			    bitmap_find_next_zero_area(map, i + 1,
459 						       i, 1, 0) != i) {
460 				if (count == 0)
461 					start = i - period_start;
462 				count++;
463 				continue;
464 			}
465 
466 			/* ith bit isn't set; don't care if count == 0 */
467 			if (count == 0)
468 				continue;
469 
470 			if (!printed)
471 				cat_printf(&buf, &buf_size, "%s %d: ",
472 					   period_name, period);
473 			else
474 				cat_printf(&buf, &buf_size, ", ");
475 			printed = true;
476 
477 			cat_printf(&buf, &buf_size, "%d %s -%3d %s", start,
478 				   units, start + count - 1, units);
479 			count = 0;
480 		}
481 
482 		if (printed)
483 			print_fn(tmp, print_data);
484 	}
485 }
486 
487 struct dwc2_qh_print_data {
488 	struct dwc2_hsotg *hsotg;
489 	struct dwc2_qh *qh;
490 };
491 
492 /**
493  * dwc2_qh_print() - Helper function for dwc2_qh_schedule_print()
494  *
495  * @str:  The string to print
496  * @data: A pointer to a struct dwc2_qh_print_data
497  */
498 static void dwc2_qh_print(const char *str, void *data)
499 {
500 	struct dwc2_qh_print_data *print_data = data;
501 
502 	dwc2_sch_dbg(print_data->hsotg, "QH=%p ...%s\n", print_data->qh, str);
503 }
504 
505 /**
506  * dwc2_qh_schedule_print() - Print the periodic schedule
507  *
508  * @hsotg: The HCD state structure for the DWC OTG controller.
509  * @qh:    QH to print.
510  */
511 static void dwc2_qh_schedule_print(struct dwc2_hsotg *hsotg,
512 				   struct dwc2_qh *qh)
513 {
514 	struct dwc2_qh_print_data print_data = { hsotg, qh };
515 	int i;
516 
517 	/*
518 	 * The printing functions are quite slow and inefficient.
519 	 * If we don't have tracing turned on, don't run unless the special
520 	 * define is turned on.
521 	 */
522 
523 	if (qh->schedule_low_speed) {
524 		unsigned long *map = dwc2_get_ls_map(hsotg, qh);
525 
526 		dwc2_sch_dbg(hsotg, "QH=%p LS/FS trans: %d=>%d us @ %d us",
527 			     qh, qh->device_us,
528 			     DWC2_ROUND_US_TO_SLICE(qh->device_us),
529 			     DWC2_US_PER_SLICE * qh->ls_start_schedule_slice);
530 
531 		if (map) {
532 			dwc2_sch_dbg(hsotg,
533 				     "QH=%p Whole low/full speed map %p now:\n",
534 				     qh, map);
535 			pmap_print(map, DWC2_LS_PERIODIC_SLICES_PER_FRAME,
536 				   DWC2_LS_SCHEDULE_FRAMES, "Frame ", "slices",
537 				   dwc2_qh_print, &print_data);
538 		}
539 	}
540 
541 	for (i = 0; i < qh->num_hs_transfers; i++) {
542 		struct dwc2_hs_transfer_time *trans_time = qh->hs_transfers + i;
543 		int uframe = trans_time->start_schedule_us /
544 			     DWC2_HS_PERIODIC_US_PER_UFRAME;
545 		int rel_us = trans_time->start_schedule_us %
546 			     DWC2_HS_PERIODIC_US_PER_UFRAME;
547 
548 		dwc2_sch_dbg(hsotg,
549 			     "QH=%p HS trans #%d: %d us @ uFrame %d + %d us\n",
550 			     qh, i, trans_time->duration_us, uframe, rel_us);
551 	}
552 	if (qh->num_hs_transfers) {
553 		dwc2_sch_dbg(hsotg, "QH=%p Whole high speed map now:\n", qh);
554 		pmap_print(hsotg->hs_periodic_bitmap,
555 			   DWC2_HS_PERIODIC_US_PER_UFRAME,
556 			   DWC2_HS_SCHEDULE_UFRAMES, "uFrame", "us",
557 			   dwc2_qh_print, &print_data);
558 	}
559 }
560 #else
561 static inline void dwc2_qh_schedule_print(struct dwc2_hsotg *hsotg,
562 					  struct dwc2_qh *qh) {};
563 #endif
564 
565 /**
566  * dwc2_ls_pmap_schedule() - Schedule a low speed QH
567  *
568  * @hsotg:        The HCD state structure for the DWC OTG controller.
569  * @qh:           QH for the periodic transfer.
570  * @search_slice: We'll start trying to schedule at the passed slice.
571  *                Remember that slices are the units of the low speed
572  *                schedule (think 25us or so).
573  *
574  * Wraps pmap_schedule() with the right parameters for low speed scheduling.
575  *
576  * Normally we schedule low speed devices on the map associated with the TT.
577  *
578  * Returns: 0 for success or an error code.
579  */
580 static int dwc2_ls_pmap_schedule(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh,
581 				 int search_slice)
582 {
583 	int slices = DIV_ROUND_UP(qh->device_us, DWC2_US_PER_SLICE);
584 	unsigned long *map = dwc2_get_ls_map(hsotg, qh);
585 	int slice;
586 
587 	if (!map)
588 		return -EINVAL;
589 
590 	/*
591 	 * Schedule on the proper low speed map with our low speed scheduling
592 	 * parameters.  Note that we use the "device_interval" here since
593 	 * we want the low speed interval and the only way we'd be in this
594 	 * function is if the device is low speed.
595 	 *
596 	 * If we happen to be doing low speed and high speed scheduling for the
597 	 * same transaction (AKA we have a split) we always do low speed first.
598 	 * That means we can always pass "false" for only_one_period (that
599 	 * parameters is only useful when we're trying to get one schedule to
600 	 * match what we already planned in the other schedule).
601 	 */
602 	slice = pmap_schedule(map, DWC2_LS_PERIODIC_SLICES_PER_FRAME,
603 			      DWC2_LS_SCHEDULE_FRAMES, slices,
604 			      qh->device_interval, search_slice, false);
605 
606 	if (slice < 0)
607 		return slice;
608 
609 	qh->ls_start_schedule_slice = slice;
610 	return 0;
611 }
612 
613 /**
614  * dwc2_ls_pmap_unschedule() - Undo work done by dwc2_ls_pmap_schedule()
615  *
616  * @hsotg:       The HCD state structure for the DWC OTG controller.
617  * @qh:          QH for the periodic transfer.
618  */
619 static void dwc2_ls_pmap_unschedule(struct dwc2_hsotg *hsotg,
620 				    struct dwc2_qh *qh)
621 {
622 	int slices = DIV_ROUND_UP(qh->device_us, DWC2_US_PER_SLICE);
623 	unsigned long *map = dwc2_get_ls_map(hsotg, qh);
624 
625 	/* Schedule should have failed, so no worries about no error code */
626 	if (!map)
627 		return;
628 
629 	pmap_unschedule(map, DWC2_LS_PERIODIC_SLICES_PER_FRAME,
630 			DWC2_LS_SCHEDULE_FRAMES, slices, qh->device_interval,
631 			qh->ls_start_schedule_slice);
632 }
633 
634 /**
635  * dwc2_hs_pmap_schedule - Schedule in the main high speed schedule
636  *
637  * This will schedule something on the main dwc2 schedule.
638  *
639  * We'll start looking in qh->hs_transfers[index].start_schedule_us.  We'll
640  * update this with the result upon success.  We also use the duration from
641  * the same structure.
642  *
643  * @hsotg:           The HCD state structure for the DWC OTG controller.
644  * @qh:              QH for the periodic transfer.
645  * @only_one_period: If true we will limit ourselves to just looking at
646  *                   one period (aka one 100us chunk).  This is used if we have
647  *                   already scheduled something on the low speed schedule and
648  *                   need to find something that matches on the high speed one.
649  * @index:           The index into qh->hs_transfers that we're working with.
650  *
651  * Returns: 0 for success or an error code.  Upon success the
652  *          dwc2_hs_transfer_time specified by "index" will be updated.
653  */
654 static int dwc2_hs_pmap_schedule(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh,
655 				 bool only_one_period, int index)
656 {
657 	struct dwc2_hs_transfer_time *trans_time = qh->hs_transfers + index;
658 	int us;
659 
660 	us = pmap_schedule(hsotg->hs_periodic_bitmap,
661 			   DWC2_HS_PERIODIC_US_PER_UFRAME,
662 			   DWC2_HS_SCHEDULE_UFRAMES, trans_time->duration_us,
663 			   qh->host_interval, trans_time->start_schedule_us,
664 			   only_one_period);
665 
666 	if (us < 0)
667 		return us;
668 
669 	trans_time->start_schedule_us = us;
670 	return 0;
671 }
672 
673 /**
674  * dwc2_ls_pmap_unschedule() - Undo work done by dwc2_hs_pmap_schedule()
675  *
676  * @hsotg:       The HCD state structure for the DWC OTG controller.
677  * @qh:          QH for the periodic transfer.
678  */
679 static void dwc2_hs_pmap_unschedule(struct dwc2_hsotg *hsotg,
680 				    struct dwc2_qh *qh, int index)
681 {
682 	struct dwc2_hs_transfer_time *trans_time = qh->hs_transfers + index;
683 
684 	pmap_unschedule(hsotg->hs_periodic_bitmap,
685 			DWC2_HS_PERIODIC_US_PER_UFRAME,
686 			DWC2_HS_SCHEDULE_UFRAMES, trans_time->duration_us,
687 			qh->host_interval, trans_time->start_schedule_us);
688 }
689 
690 /**
691  * dwc2_uframe_schedule_split - Schedule a QH for a periodic split xfer.
692  *
693  * This is the most complicated thing in USB.  We have to find matching time
694  * in both the global high speed schedule for the port and the low speed
695  * schedule for the TT associated with the given device.
696  *
697  * Being here means that the host must be running in high speed mode and the
698  * device is in low or full speed mode (and behind a hub).
699  *
700  * @hsotg:       The HCD state structure for the DWC OTG controller.
701  * @qh:          QH for the periodic transfer.
702  */
703 static int dwc2_uframe_schedule_split(struct dwc2_hsotg *hsotg,
704 				      struct dwc2_qh *qh)
705 {
706 	int bytecount = dwc2_hb_mult(qh->maxp) * dwc2_max_packet(qh->maxp);
707 	int ls_search_slice;
708 	int err = 0;
709 	int host_interval_in_sched;
710 
711 	/*
712 	 * The interval (how often to repeat) in the actual host schedule.
713 	 * See pmap_schedule() for gcd() explanation.
714 	 */
715 	host_interval_in_sched = gcd(qh->host_interval,
716 				     DWC2_HS_SCHEDULE_UFRAMES);
717 
718 	/*
719 	 * We always try to find space in the low speed schedule first, then
720 	 * try to find high speed time that matches.  If we don't, we'll bump
721 	 * up the place we start searching in the low speed schedule and try
722 	 * again.  To start we'll look right at the beginning of the low speed
723 	 * schedule.
724 	 *
725 	 * Note that this will tend to front-load the high speed schedule.
726 	 * We may eventually want to try to avoid this by either considering
727 	 * both schedules together or doing some sort of round robin.
728 	 */
729 	ls_search_slice = 0;
730 
731 	while (ls_search_slice < DWC2_LS_SCHEDULE_SLICES) {
732 		int start_s_uframe;
733 		int ssplit_s_uframe;
734 		int second_s_uframe;
735 		int rel_uframe;
736 		int first_count;
737 		int middle_count;
738 		int end_count;
739 		int first_data_bytes;
740 		int other_data_bytes;
741 		int i;
742 
743 		if (qh->schedule_low_speed) {
744 			err = dwc2_ls_pmap_schedule(hsotg, qh, ls_search_slice);
745 
746 			/*
747 			 * If we got an error here there's no other magic we
748 			 * can do, so bail.  All the looping above is only
749 			 * helpful to redo things if we got a low speed slot
750 			 * and then couldn't find a matching high speed slot.
751 			 */
752 			if (err)
753 				return err;
754 		} else {
755 			/* Must be missing the tt structure?  Why? */
756 			WARN_ON_ONCE(1);
757 		}
758 
759 		/*
760 		 * This will give us a number 0 - 7 if
761 		 * DWC2_LS_SCHEDULE_FRAMES == 1, or 0 - 15 if == 2, or ...
762 		 */
763 		start_s_uframe = qh->ls_start_schedule_slice /
764 				 DWC2_SLICES_PER_UFRAME;
765 
766 		/* Get a number that's always 0 - 7 */
767 		rel_uframe = (start_s_uframe % 8);
768 
769 		/*
770 		 * If we were going to start in uframe 7 then we would need to
771 		 * issue a start split in uframe 6, which spec says is not OK.
772 		 * Move on to the next full frame (assuming there is one).
773 		 *
774 		 * See 11.18.4 Host Split Transaction Scheduling Requirements
775 		 * bullet 1.
776 		 */
777 		if (rel_uframe == 7) {
778 			if (qh->schedule_low_speed)
779 				dwc2_ls_pmap_unschedule(hsotg, qh);
780 			ls_search_slice =
781 				(qh->ls_start_schedule_slice /
782 				 DWC2_LS_PERIODIC_SLICES_PER_FRAME + 1) *
783 				DWC2_LS_PERIODIC_SLICES_PER_FRAME;
784 			continue;
785 		}
786 
787 		/*
788 		 * For ISOC in:
789 		 * - start split            (frame -1)
790 		 * - complete split w/ data (frame +1)
791 		 * - complete split w/ data (frame +2)
792 		 * - ...
793 		 * - complete split w/ data (frame +num_data_packets)
794 		 * - complete split w/ data (frame +num_data_packets+1)
795 		 * - complete split w/ data (frame +num_data_packets+2, max 8)
796 		 *   ...though if frame was "0" then max is 7...
797 		 *
798 		 * For ISOC out we might need to do:
799 		 * - start split w/ data    (frame -1)
800 		 * - start split w/ data    (frame +0)
801 		 * - ...
802 		 * - start split w/ data    (frame +num_data_packets-2)
803 		 *
804 		 * For INTERRUPT in we might need to do:
805 		 * - start split            (frame -1)
806 		 * - complete split w/ data (frame +1)
807 		 * - complete split w/ data (frame +2)
808 		 * - complete split w/ data (frame +3, max 8)
809 		 *
810 		 * For INTERRUPT out we might need to do:
811 		 * - start split w/ data    (frame -1)
812 		 * - complete split         (frame +1)
813 		 * - complete split         (frame +2)
814 		 * - complete split         (frame +3, max 8)
815 		 *
816 		 * Start adjusting!
817 		 */
818 		ssplit_s_uframe = (start_s_uframe +
819 				   host_interval_in_sched - 1) %
820 				  host_interval_in_sched;
821 		if (qh->ep_type == USB_ENDPOINT_XFER_ISOC && !qh->ep_is_in)
822 			second_s_uframe = start_s_uframe;
823 		else
824 			second_s_uframe = start_s_uframe + 1;
825 
826 		/* First data transfer might not be all 188 bytes. */
827 		first_data_bytes = 188 -
828 			DIV_ROUND_UP(188 * (qh->ls_start_schedule_slice %
829 					    DWC2_SLICES_PER_UFRAME),
830 				     DWC2_SLICES_PER_UFRAME);
831 		if (first_data_bytes > bytecount)
832 			first_data_bytes = bytecount;
833 		other_data_bytes = bytecount - first_data_bytes;
834 
835 		/*
836 		 * For now, skip OUT xfers where first xfer is partial
837 		 *
838 		 * Main dwc2 code assumes:
839 		 * - INT transfers never get split in two.
840 		 * - ISOC transfers can always transfer 188 bytes the first
841 		 *   time.
842 		 *
843 		 * Until that code is fixed, try again if the first transfer
844 		 * couldn't transfer everything.
845 		 *
846 		 * This code can be removed if/when the rest of dwc2 handles
847 		 * the above cases.  Until it's fixed we just won't be able
848 		 * to schedule quite as tightly.
849 		 */
850 		if (!qh->ep_is_in &&
851 		    (first_data_bytes != min_t(int, 188, bytecount))) {
852 			dwc2_sch_dbg(hsotg,
853 				     "QH=%p avoiding broken 1st xfer (%d, %d)\n",
854 				     qh, first_data_bytes, bytecount);
855 			if (qh->schedule_low_speed)
856 				dwc2_ls_pmap_unschedule(hsotg, qh);
857 			ls_search_slice = (start_s_uframe + 1) *
858 				DWC2_SLICES_PER_UFRAME;
859 			continue;
860 		}
861 
862 		/* Start by assuming transfers for the bytes */
863 		qh->num_hs_transfers = 1 + DIV_ROUND_UP(other_data_bytes, 188);
864 
865 		/*
866 		 * Everything except ISOC OUT has extra transfers.  Rules are
867 		 * complicated.  See 11.18.4 Host Split Transaction Scheduling
868 		 * Requirements bullet 3.
869 		 */
870 		if (qh->ep_type == USB_ENDPOINT_XFER_INT) {
871 			if (rel_uframe == 6)
872 				qh->num_hs_transfers += 2;
873 			else
874 				qh->num_hs_transfers += 3;
875 
876 			if (qh->ep_is_in) {
877 				/*
878 				 * First is start split, middle/end is data.
879 				 * Allocate full data bytes for all data.
880 				 */
881 				first_count = 4;
882 				middle_count = bytecount;
883 				end_count = bytecount;
884 			} else {
885 				/*
886 				 * First is data, middle/end is complete.
887 				 * First transfer and second can have data.
888 				 * Rest should just have complete split.
889 				 */
890 				first_count = first_data_bytes;
891 				middle_count = max_t(int, 4, other_data_bytes);
892 				end_count = 4;
893 			}
894 		} else {
895 			if (qh->ep_is_in) {
896 				int last;
897 
898 				/* Account for the start split */
899 				qh->num_hs_transfers++;
900 
901 				/* Calculate "L" value from spec */
902 				last = rel_uframe + qh->num_hs_transfers + 1;
903 
904 				/* Start with basic case */
905 				if (last <= 6)
906 					qh->num_hs_transfers += 2;
907 				else
908 					qh->num_hs_transfers += 1;
909 
910 				/* Adjust downwards */
911 				if (last >= 6 && rel_uframe == 0)
912 					qh->num_hs_transfers--;
913 
914 				/* 1st = start; rest can contain data */
915 				first_count = 4;
916 				middle_count = min_t(int, 188, bytecount);
917 				end_count = middle_count;
918 			} else {
919 				/* All contain data, last might be smaller */
920 				first_count = first_data_bytes;
921 				middle_count = min_t(int, 188,
922 						     other_data_bytes);
923 				end_count = other_data_bytes % 188;
924 			}
925 		}
926 
927 		/* Assign durations per uFrame */
928 		qh->hs_transfers[0].duration_us = HS_USECS_ISO(first_count);
929 		for (i = 1; i < qh->num_hs_transfers - 1; i++)
930 			qh->hs_transfers[i].duration_us =
931 				HS_USECS_ISO(middle_count);
932 		if (qh->num_hs_transfers > 1)
933 			qh->hs_transfers[qh->num_hs_transfers - 1].duration_us =
934 				HS_USECS_ISO(end_count);
935 
936 		/*
937 		 * Assign start us.  The call below to dwc2_hs_pmap_schedule()
938 		 * will start with these numbers but may adjust within the same
939 		 * microframe.
940 		 */
941 		qh->hs_transfers[0].start_schedule_us =
942 			ssplit_s_uframe * DWC2_HS_PERIODIC_US_PER_UFRAME;
943 		for (i = 1; i < qh->num_hs_transfers; i++)
944 			qh->hs_transfers[i].start_schedule_us =
945 				((second_s_uframe + i - 1) %
946 				 DWC2_HS_SCHEDULE_UFRAMES) *
947 				DWC2_HS_PERIODIC_US_PER_UFRAME;
948 
949 		/* Try to schedule with filled in hs_transfers above */
950 		for (i = 0; i < qh->num_hs_transfers; i++) {
951 			err = dwc2_hs_pmap_schedule(hsotg, qh, true, i);
952 			if (err)
953 				break;
954 		}
955 
956 		/* If we scheduled all w/out breaking out then we're all good */
957 		if (i == qh->num_hs_transfers)
958 			break;
959 
960 		for (; i >= 0; i--)
961 			dwc2_hs_pmap_unschedule(hsotg, qh, i);
962 
963 		if (qh->schedule_low_speed)
964 			dwc2_ls_pmap_unschedule(hsotg, qh);
965 
966 		/* Try again starting in the next microframe */
967 		ls_search_slice = (start_s_uframe + 1) * DWC2_SLICES_PER_UFRAME;
968 	}
969 
970 	if (ls_search_slice >= DWC2_LS_SCHEDULE_SLICES)
971 		return -ENOSPC;
972 
973 	return 0;
974 }
975 
976 /**
977  * dwc2_uframe_schedule_hs - Schedule a QH for a periodic high speed xfer.
978  *
979  * Basically this just wraps dwc2_hs_pmap_schedule() to provide a clean
980  * interface.
981  *
982  * @hsotg:       The HCD state structure for the DWC OTG controller.
983  * @qh:          QH for the periodic transfer.
984  */
985 static int dwc2_uframe_schedule_hs(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh)
986 {
987 	/* In non-split host and device time are the same */
988 	WARN_ON(qh->host_us != qh->device_us);
989 	WARN_ON(qh->host_interval != qh->device_interval);
990 	WARN_ON(qh->num_hs_transfers != 1);
991 
992 	/* We'll have one transfer; init start to 0 before calling scheduler */
993 	qh->hs_transfers[0].start_schedule_us = 0;
994 	qh->hs_transfers[0].duration_us = qh->host_us;
995 
996 	return dwc2_hs_pmap_schedule(hsotg, qh, false, 0);
997 }
998 
999 /**
1000  * dwc2_uframe_schedule_ls - Schedule a QH for a periodic low/full speed xfer.
1001  *
1002  * Basically this just wraps dwc2_ls_pmap_schedule() to provide a clean
1003  * interface.
1004  *
1005  * @hsotg:       The HCD state structure for the DWC OTG controller.
1006  * @qh:          QH for the periodic transfer.
1007  */
1008 static int dwc2_uframe_schedule_ls(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh)
1009 {
1010 	/* In non-split host and device time are the same */
1011 	WARN_ON(qh->host_us != qh->device_us);
1012 	WARN_ON(qh->host_interval != qh->device_interval);
1013 	WARN_ON(!qh->schedule_low_speed);
1014 
1015 	/* Run on the main low speed schedule (no split = no hub = no TT) */
1016 	return dwc2_ls_pmap_schedule(hsotg, qh, 0);
1017 }
1018 
1019 /**
1020  * dwc2_uframe_schedule - Schedule a QH for a periodic xfer.
1021  *
1022  * Calls one of the 3 sub-function depending on what type of transfer this QH
1023  * is for.  Also adds some printing.
1024  *
1025  * @hsotg:       The HCD state structure for the DWC OTG controller.
1026  * @qh:          QH for the periodic transfer.
1027  */
1028 static int dwc2_uframe_schedule(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh)
1029 {
1030 	int ret;
1031 
1032 	if (qh->dev_speed == USB_SPEED_HIGH)
1033 		ret = dwc2_uframe_schedule_hs(hsotg, qh);
1034 	else if (!qh->do_split)
1035 		ret = dwc2_uframe_schedule_ls(hsotg, qh);
1036 	else
1037 		ret = dwc2_uframe_schedule_split(hsotg, qh);
1038 
1039 	if (ret)
1040 		dwc2_sch_dbg(hsotg, "QH=%p Failed to schedule %d\n", qh, ret);
1041 	else
1042 		dwc2_qh_schedule_print(hsotg, qh);
1043 
1044 	return ret;
1045 }
1046 
1047 /**
1048  * dwc2_uframe_unschedule - Undoes dwc2_uframe_schedule().
1049  *
1050  * @hsotg:       The HCD state structure for the DWC OTG controller.
1051  * @qh:          QH for the periodic transfer.
1052  */
1053 static void dwc2_uframe_unschedule(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh)
1054 {
1055 	int i;
1056 
1057 	for (i = 0; i < qh->num_hs_transfers; i++)
1058 		dwc2_hs_pmap_unschedule(hsotg, qh, i);
1059 
1060 	if (qh->schedule_low_speed)
1061 		dwc2_ls_pmap_unschedule(hsotg, qh);
1062 
1063 	dwc2_sch_dbg(hsotg, "QH=%p Unscheduled\n", qh);
1064 }
1065 
1066 /**
1067  * dwc2_pick_first_frame() - Choose 1st frame for qh that's already scheduled
1068  *
1069  * Takes a qh that has already been scheduled (which means we know we have the
1070  * bandwdith reserved for us) and set the next_active_frame and the
1071  * start_active_frame.
1072  *
1073  * This is expected to be called on qh's that weren't previously actively
1074  * running.  It just picks the next frame that we can fit into without any
1075  * thought about the past.
1076  *
1077  * @hsotg: The HCD state structure for the DWC OTG controller
1078  * @qh:    QH for a periodic endpoint
1079  *
1080  */
1081 static void dwc2_pick_first_frame(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh)
1082 {
1083 	u16 frame_number;
1084 	u16 earliest_frame;
1085 	u16 next_active_frame;
1086 	u16 relative_frame;
1087 	u16 interval;
1088 
1089 	/*
1090 	 * Use the real frame number rather than the cached value as of the
1091 	 * last SOF to give us a little extra slop.
1092 	 */
1093 	frame_number = dwc2_hcd_get_frame_number(hsotg);
1094 
1095 	/*
1096 	 * We wouldn't want to start any earlier than the next frame just in
1097 	 * case the frame number ticks as we're doing this calculation.
1098 	 *
1099 	 * NOTE: if we could quantify how long till we actually get scheduled
1100 	 * we might be able to avoid the "+ 1" by looking at the upper part of
1101 	 * HFNUM (the FRREM field).  For now we'll just use the + 1 though.
1102 	 */
1103 	earliest_frame = dwc2_frame_num_inc(frame_number, 1);
1104 	next_active_frame = earliest_frame;
1105 
1106 	/* Get the "no microframe schduler" out of the way... */
1107 	if (!hsotg->params.uframe_sched) {
1108 		if (qh->do_split)
1109 			/* Splits are active at microframe 0 minus 1 */
1110 			next_active_frame |= 0x7;
1111 		goto exit;
1112 	}
1113 
1114 	if (qh->dev_speed == USB_SPEED_HIGH || qh->do_split) {
1115 		/*
1116 		 * We're either at high speed or we're doing a split (which
1117 		 * means we're talking high speed to a hub).  In any case
1118 		 * the first frame should be based on when the first scheduled
1119 		 * event is.
1120 		 */
1121 		WARN_ON(qh->num_hs_transfers < 1);
1122 
1123 		relative_frame = qh->hs_transfers[0].start_schedule_us /
1124 				 DWC2_HS_PERIODIC_US_PER_UFRAME;
1125 
1126 		/* Adjust interval as per high speed schedule */
1127 		interval = gcd(qh->host_interval, DWC2_HS_SCHEDULE_UFRAMES);
1128 
1129 	} else {
1130 		/*
1131 		 * Low or full speed directly on dwc2.  Just about the same
1132 		 * as high speed but on a different schedule and with slightly
1133 		 * different adjustments.  Note that this works because when
1134 		 * the host and device are both low speed then frames in the
1135 		 * controller tick at low speed.
1136 		 */
1137 		relative_frame = qh->ls_start_schedule_slice /
1138 				 DWC2_LS_PERIODIC_SLICES_PER_FRAME;
1139 		interval = gcd(qh->host_interval, DWC2_LS_SCHEDULE_FRAMES);
1140 	}
1141 
1142 	/* Scheduler messed up if frame is past interval */
1143 	WARN_ON(relative_frame >= interval);
1144 
1145 	/*
1146 	 * We know interval must divide (HFNUM_MAX_FRNUM + 1) now that we've
1147 	 * done the gcd(), so it's safe to move to the beginning of the current
1148 	 * interval like this.
1149 	 *
1150 	 * After this we might be before earliest_frame, but don't worry,
1151 	 * we'll fix it...
1152 	 */
1153 	next_active_frame = (next_active_frame / interval) * interval;
1154 
1155 	/*
1156 	 * Actually choose to start at the frame number we've been
1157 	 * scheduled for.
1158 	 */
1159 	next_active_frame = dwc2_frame_num_inc(next_active_frame,
1160 					       relative_frame);
1161 
1162 	/*
1163 	 * We actually need 1 frame before since the next_active_frame is
1164 	 * the frame number we'll be put on the ready list and we won't be on
1165 	 * the bus until 1 frame later.
1166 	 */
1167 	next_active_frame = dwc2_frame_num_dec(next_active_frame, 1);
1168 
1169 	/*
1170 	 * By now we might actually be before the earliest_frame.  Let's move
1171 	 * up intervals until we're not.
1172 	 */
1173 	while (dwc2_frame_num_gt(earliest_frame, next_active_frame))
1174 		next_active_frame = dwc2_frame_num_inc(next_active_frame,
1175 						       interval);
1176 
1177 exit:
1178 	qh->next_active_frame = next_active_frame;
1179 	qh->start_active_frame = next_active_frame;
1180 
1181 	dwc2_sch_vdbg(hsotg, "QH=%p First fn=%04x nxt=%04x\n",
1182 		      qh, frame_number, qh->next_active_frame);
1183 }
1184 
1185 /**
1186  * dwc2_do_reserve() - Make a periodic reservation
1187  *
1188  * Try to allocate space in the periodic schedule.  Depending on parameters
1189  * this might use the microframe scheduler or the dumb scheduler.
1190  *
1191  * @hsotg: The HCD state structure for the DWC OTG controller
1192  * @qh:    QH for the periodic transfer.
1193  *
1194  * Returns: 0 upon success; error upon failure.
1195  */
1196 static int dwc2_do_reserve(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh)
1197 {
1198 	int status;
1199 
1200 	if (hsotg->params.uframe_sched) {
1201 		status = dwc2_uframe_schedule(hsotg, qh);
1202 	} else {
1203 		status = dwc2_periodic_channel_available(hsotg);
1204 		if (status) {
1205 			dev_info(hsotg->dev,
1206 				 "%s: No host channel available for periodic transfer\n",
1207 				 __func__);
1208 			return status;
1209 		}
1210 
1211 		status = dwc2_check_periodic_bandwidth(hsotg, qh);
1212 	}
1213 
1214 	if (status) {
1215 		dev_dbg(hsotg->dev,
1216 			"%s: Insufficient periodic bandwidth for periodic transfer\n",
1217 			__func__);
1218 		return status;
1219 	}
1220 
1221 	if (!hsotg->params.uframe_sched)
1222 		/* Reserve periodic channel */
1223 		hsotg->periodic_channels++;
1224 
1225 	/* Update claimed usecs per (micro)frame */
1226 	hsotg->periodic_usecs += qh->host_us;
1227 
1228 	dwc2_pick_first_frame(hsotg, qh);
1229 
1230 	return 0;
1231 }
1232 
1233 /**
1234  * dwc2_do_unreserve() - Actually release the periodic reservation
1235  *
1236  * This function actually releases the periodic bandwidth that was reserved
1237  * by the given qh.
1238  *
1239  * @hsotg: The HCD state structure for the DWC OTG controller
1240  * @qh:    QH for the periodic transfer.
1241  */
1242 static void dwc2_do_unreserve(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh)
1243 {
1244 	assert_spin_locked(&hsotg->lock);
1245 
1246 	WARN_ON(!qh->unreserve_pending);
1247 
1248 	/* No more unreserve pending--we're doing it */
1249 	qh->unreserve_pending = false;
1250 
1251 	if (WARN_ON(!list_empty(&qh->qh_list_entry)))
1252 		list_del_init(&qh->qh_list_entry);
1253 
1254 	/* Update claimed usecs per (micro)frame */
1255 	hsotg->periodic_usecs -= qh->host_us;
1256 
1257 	if (hsotg->params.uframe_sched) {
1258 		dwc2_uframe_unschedule(hsotg, qh);
1259 	} else {
1260 		/* Release periodic channel reservation */
1261 		hsotg->periodic_channels--;
1262 	}
1263 }
1264 
1265 /**
1266  * dwc2_unreserve_timer_fn() - Timer function to release periodic reservation
1267  *
1268  * According to the kernel doc for usb_submit_urb() (specifically the part about
1269  * "Reserved Bandwidth Transfers"), we need to keep a reservation active as
1270  * long as a device driver keeps submitting.  Since we're using HCD_BH to give
1271  * back the URB we need to give the driver a little bit of time before we
1272  * release the reservation.  This worker is called after the appropriate
1273  * delay.
1274  *
1275  * @work: Pointer to a qh unreserve_work.
1276  */
1277 static void dwc2_unreserve_timer_fn(unsigned long data)
1278 {
1279 	struct dwc2_qh *qh = (struct dwc2_qh *)data;
1280 	struct dwc2_hsotg *hsotg = qh->hsotg;
1281 	unsigned long flags;
1282 
1283 	/*
1284 	 * Wait for the lock, or for us to be scheduled again.  We
1285 	 * could be scheduled again if:
1286 	 * - We started executing but didn't get the lock yet.
1287 	 * - A new reservation came in, but cancel didn't take effect
1288 	 *   because we already started executing.
1289 	 * - The timer has been kicked again.
1290 	 * In that case cancel and wait for the next call.
1291 	 */
1292 	while (!spin_trylock_irqsave(&hsotg->lock, flags)) {
1293 		if (timer_pending(&qh->unreserve_timer))
1294 			return;
1295 	}
1296 
1297 	/*
1298 	 * Might be no more unreserve pending if:
1299 	 * - We started executing but didn't get the lock yet.
1300 	 * - A new reservation came in, but cancel didn't take effect
1301 	 *   because we already started executing.
1302 	 *
1303 	 * We can't put this in the loop above because unreserve_pending needs
1304 	 * to be accessed under lock, so we can only check it once we got the
1305 	 * lock.
1306 	 */
1307 	if (qh->unreserve_pending)
1308 		dwc2_do_unreserve(hsotg, qh);
1309 
1310 	spin_unlock_irqrestore(&hsotg->lock, flags);
1311 }
1312 
1313 /**
1314  * dwc2_check_max_xfer_size() - Checks that the max transfer size allowed in a
1315  * host channel is large enough to handle the maximum data transfer in a single
1316  * (micro)frame for a periodic transfer
1317  *
1318  * @hsotg: The HCD state structure for the DWC OTG controller
1319  * @qh:    QH for a periodic endpoint
1320  *
1321  * Return: 0 if successful, negative error code otherwise
1322  */
1323 static int dwc2_check_max_xfer_size(struct dwc2_hsotg *hsotg,
1324 				    struct dwc2_qh *qh)
1325 {
1326 	u32 max_xfer_size;
1327 	u32 max_channel_xfer_size;
1328 	int status = 0;
1329 
1330 	max_xfer_size = dwc2_max_packet(qh->maxp) * dwc2_hb_mult(qh->maxp);
1331 	max_channel_xfer_size = hsotg->params.max_transfer_size;
1332 
1333 	if (max_xfer_size > max_channel_xfer_size) {
1334 		dev_err(hsotg->dev,
1335 			"%s: Periodic xfer length %d > max xfer length for channel %d\n",
1336 			__func__, max_xfer_size, max_channel_xfer_size);
1337 		status = -ENOSPC;
1338 	}
1339 
1340 	return status;
1341 }
1342 
1343 /**
1344  * dwc2_schedule_periodic() - Schedules an interrupt or isochronous transfer in
1345  * the periodic schedule
1346  *
1347  * @hsotg: The HCD state structure for the DWC OTG controller
1348  * @qh:    QH for the periodic transfer. The QH should already contain the
1349  *         scheduling information.
1350  *
1351  * Return: 0 if successful, negative error code otherwise
1352  */
1353 static int dwc2_schedule_periodic(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh)
1354 {
1355 	int status;
1356 
1357 	status = dwc2_check_max_xfer_size(hsotg, qh);
1358 	if (status) {
1359 		dev_dbg(hsotg->dev,
1360 			"%s: Channel max transfer size too small for periodic transfer\n",
1361 			__func__);
1362 		return status;
1363 	}
1364 
1365 	/* Cancel pending unreserve; if canceled OK, unreserve was pending */
1366 	if (del_timer(&qh->unreserve_timer))
1367 		WARN_ON(!qh->unreserve_pending);
1368 
1369 	/*
1370 	 * Only need to reserve if there's not an unreserve pending, since if an
1371 	 * unreserve is pending then by definition our old reservation is still
1372 	 * valid.  Unreserve might still be pending even if we didn't cancel if
1373 	 * dwc2_unreserve_timer_fn() already started.  Code in the timer handles
1374 	 * that case.
1375 	 */
1376 	if (!qh->unreserve_pending) {
1377 		status = dwc2_do_reserve(hsotg, qh);
1378 		if (status)
1379 			return status;
1380 	} else {
1381 		/*
1382 		 * It might have been a while, so make sure that frame_number
1383 		 * is still good.  Note: we could also try to use the similar
1384 		 * dwc2_next_periodic_start() but that schedules much more
1385 		 * tightly and we might need to hurry and queue things up.
1386 		 */
1387 		if (dwc2_frame_num_le(qh->next_active_frame,
1388 				      hsotg->frame_number))
1389 			dwc2_pick_first_frame(hsotg, qh);
1390 	}
1391 
1392 	qh->unreserve_pending = 0;
1393 
1394 	if (hsotg->params.dma_desc_enable)
1395 		/* Don't rely on SOF and start in ready schedule */
1396 		list_add_tail(&qh->qh_list_entry, &hsotg->periodic_sched_ready);
1397 	else
1398 		/* Always start in inactive schedule */
1399 		list_add_tail(&qh->qh_list_entry,
1400 			      &hsotg->periodic_sched_inactive);
1401 
1402 	return 0;
1403 }
1404 
1405 /**
1406  * dwc2_deschedule_periodic() - Removes an interrupt or isochronous transfer
1407  * from the periodic schedule
1408  *
1409  * @hsotg: The HCD state structure for the DWC OTG controller
1410  * @qh:	   QH for the periodic transfer
1411  */
1412 static void dwc2_deschedule_periodic(struct dwc2_hsotg *hsotg,
1413 				     struct dwc2_qh *qh)
1414 {
1415 	bool did_modify;
1416 
1417 	assert_spin_locked(&hsotg->lock);
1418 
1419 	/*
1420 	 * Schedule the unreserve to happen in a little bit.  Cases here:
1421 	 * - Unreserve worker might be sitting there waiting to grab the lock.
1422 	 *   In this case it will notice it's been schedule again and will
1423 	 *   quit.
1424 	 * - Unreserve worker might not be scheduled.
1425 	 *
1426 	 * We should never already be scheduled since dwc2_schedule_periodic()
1427 	 * should have canceled the scheduled unreserve timer (hence the
1428 	 * warning on did_modify).
1429 	 *
1430 	 * We add + 1 to the timer to guarantee that at least 1 jiffy has
1431 	 * passed (otherwise if the jiffy counter might tick right after we
1432 	 * read it and we'll get no delay).
1433 	 */
1434 	did_modify = mod_timer(&qh->unreserve_timer,
1435 			       jiffies + DWC2_UNRESERVE_DELAY + 1);
1436 	WARN_ON(did_modify);
1437 	qh->unreserve_pending = 1;
1438 
1439 	list_del_init(&qh->qh_list_entry);
1440 }
1441 
1442 /**
1443  * dwc2_qh_init() - Initializes a QH structure
1444  *
1445  * @hsotg: The HCD state structure for the DWC OTG controller
1446  * @qh:    The QH to init
1447  * @urb:   Holds the information about the device/endpoint needed to initialize
1448  *         the QH
1449  * @mem_flags: Flags for allocating memory.
1450  */
1451 static void dwc2_qh_init(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh,
1452 			 struct dwc2_hcd_urb *urb, gfp_t mem_flags)
1453 {
1454 	int dev_speed = dwc2_host_get_speed(hsotg, urb->priv);
1455 	u8 ep_type = dwc2_hcd_get_pipe_type(&urb->pipe_info);
1456 	bool ep_is_in = !!dwc2_hcd_is_pipe_in(&urb->pipe_info);
1457 	bool ep_is_isoc = (ep_type == USB_ENDPOINT_XFER_ISOC);
1458 	bool ep_is_int = (ep_type == USB_ENDPOINT_XFER_INT);
1459 	u32 hprt = dwc2_readl(hsotg->regs + HPRT0);
1460 	u32 prtspd = (hprt & HPRT0_SPD_MASK) >> HPRT0_SPD_SHIFT;
1461 	bool do_split = (prtspd == HPRT0_SPD_HIGH_SPEED &&
1462 			 dev_speed != USB_SPEED_HIGH);
1463 	int maxp = dwc2_hcd_get_mps(&urb->pipe_info);
1464 	int bytecount = dwc2_hb_mult(maxp) * dwc2_max_packet(maxp);
1465 	char *speed, *type;
1466 
1467 	/* Initialize QH */
1468 	qh->hsotg = hsotg;
1469 	setup_timer(&qh->unreserve_timer, dwc2_unreserve_timer_fn,
1470 		    (unsigned long)qh);
1471 	qh->ep_type = ep_type;
1472 	qh->ep_is_in = ep_is_in;
1473 
1474 	qh->data_toggle = DWC2_HC_PID_DATA0;
1475 	qh->maxp = maxp;
1476 	INIT_LIST_HEAD(&qh->qtd_list);
1477 	INIT_LIST_HEAD(&qh->qh_list_entry);
1478 
1479 	qh->do_split = do_split;
1480 	qh->dev_speed = dev_speed;
1481 
1482 	if (ep_is_int || ep_is_isoc) {
1483 		/* Compute scheduling parameters once and save them */
1484 		int host_speed = do_split ? USB_SPEED_HIGH : dev_speed;
1485 		struct dwc2_tt *dwc_tt = dwc2_host_get_tt_info(hsotg, urb->priv,
1486 							       mem_flags,
1487 							       &qh->ttport);
1488 		int device_ns;
1489 
1490 		qh->dwc_tt = dwc_tt;
1491 
1492 		qh->host_us = NS_TO_US(usb_calc_bus_time(host_speed, ep_is_in,
1493 				       ep_is_isoc, bytecount));
1494 		device_ns = usb_calc_bus_time(dev_speed, ep_is_in,
1495 					      ep_is_isoc, bytecount);
1496 
1497 		if (do_split && dwc_tt)
1498 			device_ns += dwc_tt->usb_tt->think_time;
1499 		qh->device_us = NS_TO_US(device_ns);
1500 
1501 		qh->device_interval = urb->interval;
1502 		qh->host_interval = urb->interval * (do_split ? 8 : 1);
1503 
1504 		/*
1505 		 * Schedule low speed if we're running the host in low or
1506 		 * full speed OR if we've got a "TT" to deal with to access this
1507 		 * device.
1508 		 */
1509 		qh->schedule_low_speed = prtspd != HPRT0_SPD_HIGH_SPEED ||
1510 					 dwc_tt;
1511 
1512 		if (do_split) {
1513 			/* We won't know num transfers until we schedule */
1514 			qh->num_hs_transfers = -1;
1515 		} else if (dev_speed == USB_SPEED_HIGH) {
1516 			qh->num_hs_transfers = 1;
1517 		} else {
1518 			qh->num_hs_transfers = 0;
1519 		}
1520 
1521 		/* We'll schedule later when we have something to do */
1522 	}
1523 
1524 	switch (dev_speed) {
1525 	case USB_SPEED_LOW:
1526 		speed = "low";
1527 		break;
1528 	case USB_SPEED_FULL:
1529 		speed = "full";
1530 		break;
1531 	case USB_SPEED_HIGH:
1532 		speed = "high";
1533 		break;
1534 	default:
1535 		speed = "?";
1536 		break;
1537 	}
1538 
1539 	switch (qh->ep_type) {
1540 	case USB_ENDPOINT_XFER_ISOC:
1541 		type = "isochronous";
1542 		break;
1543 	case USB_ENDPOINT_XFER_INT:
1544 		type = "interrupt";
1545 		break;
1546 	case USB_ENDPOINT_XFER_CONTROL:
1547 		type = "control";
1548 		break;
1549 	case USB_ENDPOINT_XFER_BULK:
1550 		type = "bulk";
1551 		break;
1552 	default:
1553 		type = "?";
1554 		break;
1555 	}
1556 
1557 	dwc2_sch_dbg(hsotg, "QH=%p Init %s, %s speed, %d bytes:\n", qh, type,
1558 		     speed, bytecount);
1559 	dwc2_sch_dbg(hsotg, "QH=%p ...addr=%d, ep=%d, %s\n", qh,
1560 		     dwc2_hcd_get_dev_addr(&urb->pipe_info),
1561 		     dwc2_hcd_get_ep_num(&urb->pipe_info),
1562 		     ep_is_in ? "IN" : "OUT");
1563 	if (ep_is_int || ep_is_isoc) {
1564 		dwc2_sch_dbg(hsotg,
1565 			     "QH=%p ...duration: host=%d us, device=%d us\n",
1566 			     qh, qh->host_us, qh->device_us);
1567 		dwc2_sch_dbg(hsotg, "QH=%p ...interval: host=%d, device=%d\n",
1568 			     qh, qh->host_interval, qh->device_interval);
1569 		if (qh->schedule_low_speed)
1570 			dwc2_sch_dbg(hsotg, "QH=%p ...low speed schedule=%p\n",
1571 				     qh, dwc2_get_ls_map(hsotg, qh));
1572 	}
1573 }
1574 
1575 /**
1576  * dwc2_hcd_qh_create() - Allocates and initializes a QH
1577  *
1578  * @hsotg:        The HCD state structure for the DWC OTG controller
1579  * @urb:          Holds the information about the device/endpoint needed
1580  *                to initialize the QH
1581  * @atomic_alloc: Flag to do atomic allocation if needed
1582  *
1583  * Return: Pointer to the newly allocated QH, or NULL on error
1584  */
1585 struct dwc2_qh *dwc2_hcd_qh_create(struct dwc2_hsotg *hsotg,
1586 				   struct dwc2_hcd_urb *urb,
1587 					  gfp_t mem_flags)
1588 {
1589 	struct dwc2_qh *qh;
1590 
1591 	if (!urb->priv)
1592 		return NULL;
1593 
1594 	/* Allocate memory */
1595 	qh = kzalloc(sizeof(*qh), mem_flags);
1596 	if (!qh)
1597 		return NULL;
1598 
1599 	dwc2_qh_init(hsotg, qh, urb, mem_flags);
1600 
1601 	if (hsotg->params.dma_desc_enable &&
1602 	    dwc2_hcd_qh_init_ddma(hsotg, qh, mem_flags) < 0) {
1603 		dwc2_hcd_qh_free(hsotg, qh);
1604 		return NULL;
1605 	}
1606 
1607 	return qh;
1608 }
1609 
1610 /**
1611  * dwc2_hcd_qh_free() - Frees the QH
1612  *
1613  * @hsotg: HCD instance
1614  * @qh:    The QH to free
1615  *
1616  * QH should already be removed from the list. QTD list should already be empty
1617  * if called from URB Dequeue.
1618  *
1619  * Must NOT be called with interrupt disabled or spinlock held
1620  */
1621 void dwc2_hcd_qh_free(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh)
1622 {
1623 	/* Make sure any unreserve work is finished. */
1624 	if (del_timer_sync(&qh->unreserve_timer)) {
1625 		unsigned long flags;
1626 
1627 		spin_lock_irqsave(&hsotg->lock, flags);
1628 		dwc2_do_unreserve(hsotg, qh);
1629 		spin_unlock_irqrestore(&hsotg->lock, flags);
1630 	}
1631 	dwc2_host_put_tt_info(hsotg, qh->dwc_tt);
1632 
1633 	if (qh->desc_list)
1634 		dwc2_hcd_qh_free_ddma(hsotg, qh);
1635 	kfree(qh);
1636 }
1637 
1638 /**
1639  * dwc2_hcd_qh_add() - Adds a QH to either the non periodic or periodic
1640  * schedule if it is not already in the schedule. If the QH is already in
1641  * the schedule, no action is taken.
1642  *
1643  * @hsotg: The HCD state structure for the DWC OTG controller
1644  * @qh:    The QH to add
1645  *
1646  * Return: 0 if successful, negative error code otherwise
1647  */
1648 int dwc2_hcd_qh_add(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh)
1649 {
1650 	int status;
1651 	u32 intr_mask;
1652 
1653 	if (dbg_qh(qh))
1654 		dev_vdbg(hsotg->dev, "%s()\n", __func__);
1655 
1656 	if (!list_empty(&qh->qh_list_entry))
1657 		/* QH already in a schedule */
1658 		return 0;
1659 
1660 	/* Add the new QH to the appropriate schedule */
1661 	if (dwc2_qh_is_non_per(qh)) {
1662 		/* Schedule right away */
1663 		qh->start_active_frame = hsotg->frame_number;
1664 		qh->next_active_frame = qh->start_active_frame;
1665 
1666 		/* Always start in inactive schedule */
1667 		list_add_tail(&qh->qh_list_entry,
1668 			      &hsotg->non_periodic_sched_inactive);
1669 		return 0;
1670 	}
1671 
1672 	status = dwc2_schedule_periodic(hsotg, qh);
1673 	if (status)
1674 		return status;
1675 	if (!hsotg->periodic_qh_count) {
1676 		intr_mask = dwc2_readl(hsotg->regs + GINTMSK);
1677 		intr_mask |= GINTSTS_SOF;
1678 		dwc2_writel(intr_mask, hsotg->regs + GINTMSK);
1679 	}
1680 	hsotg->periodic_qh_count++;
1681 
1682 	return 0;
1683 }
1684 
1685 /**
1686  * dwc2_hcd_qh_unlink() - Removes a QH from either the non-periodic or periodic
1687  * schedule. Memory is not freed.
1688  *
1689  * @hsotg: The HCD state structure
1690  * @qh:    QH to remove from schedule
1691  */
1692 void dwc2_hcd_qh_unlink(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh)
1693 {
1694 	u32 intr_mask;
1695 
1696 	dev_vdbg(hsotg->dev, "%s()\n", __func__);
1697 
1698 	if (list_empty(&qh->qh_list_entry))
1699 		/* QH is not in a schedule */
1700 		return;
1701 
1702 	if (dwc2_qh_is_non_per(qh)) {
1703 		if (hsotg->non_periodic_qh_ptr == &qh->qh_list_entry)
1704 			hsotg->non_periodic_qh_ptr =
1705 					hsotg->non_periodic_qh_ptr->next;
1706 		list_del_init(&qh->qh_list_entry);
1707 		return;
1708 	}
1709 
1710 	dwc2_deschedule_periodic(hsotg, qh);
1711 	hsotg->periodic_qh_count--;
1712 	if (!hsotg->periodic_qh_count &&
1713 	    !hsotg->params.dma_desc_enable) {
1714 		intr_mask = dwc2_readl(hsotg->regs + GINTMSK);
1715 		intr_mask &= ~GINTSTS_SOF;
1716 		dwc2_writel(intr_mask, hsotg->regs + GINTMSK);
1717 	}
1718 }
1719 
1720 /**
1721  * dwc2_next_for_periodic_split() - Set next_active_frame midway thru a split.
1722  *
1723  * This is called for setting next_active_frame for periodic splits for all but
1724  * the first packet of the split.  Confusing?  I thought so...
1725  *
1726  * Periodic splits are single low/full speed transfers that we end up splitting
1727  * up into several high speed transfers.  They always fit into one full (1 ms)
1728  * frame but might be split over several microframes (125 us each).  We to put
1729  * each of the parts on a very specific high speed frame.
1730  *
1731  * This function figures out where the next active uFrame needs to be.
1732  *
1733  * @hsotg:        The HCD state structure
1734  * @qh:           QH for the periodic transfer.
1735  * @frame_number: The current frame number.
1736  *
1737  * Return: number missed by (or 0 if we didn't miss).
1738  */
1739 static int dwc2_next_for_periodic_split(struct dwc2_hsotg *hsotg,
1740 					struct dwc2_qh *qh, u16 frame_number)
1741 {
1742 	u16 old_frame = qh->next_active_frame;
1743 	u16 prev_frame_number = dwc2_frame_num_dec(frame_number, 1);
1744 	int missed = 0;
1745 	u16 incr;
1746 
1747 	/*
1748 	 * See dwc2_uframe_schedule_split() for split scheduling.
1749 	 *
1750 	 * Basically: increment 1 normally, but 2 right after the start split
1751 	 * (except for ISOC out).
1752 	 */
1753 	if (old_frame == qh->start_active_frame &&
1754 	    !(qh->ep_type == USB_ENDPOINT_XFER_ISOC && !qh->ep_is_in))
1755 		incr = 2;
1756 	else
1757 		incr = 1;
1758 
1759 	qh->next_active_frame = dwc2_frame_num_inc(old_frame, incr);
1760 
1761 	/*
1762 	 * Note that it's OK for frame_number to be 1 frame past
1763 	 * next_active_frame.  Remember that next_active_frame is supposed to
1764 	 * be 1 frame _before_ when we want to be scheduled.  If we're 1 frame
1765 	 * past it just means schedule ASAP.
1766 	 *
1767 	 * It's _not_ OK, however, if we're more than one frame past.
1768 	 */
1769 	if (dwc2_frame_num_gt(prev_frame_number, qh->next_active_frame)) {
1770 		/*
1771 		 * OOPS, we missed.  That's actually pretty bad since
1772 		 * the hub will be unhappy; try ASAP I guess.
1773 		 */
1774 		missed = dwc2_frame_num_dec(prev_frame_number,
1775 					    qh->next_active_frame);
1776 		qh->next_active_frame = frame_number;
1777 	}
1778 
1779 	return missed;
1780 }
1781 
1782 /**
1783  * dwc2_next_periodic_start() - Set next_active_frame for next transfer start
1784  *
1785  * This is called for setting next_active_frame for a periodic transfer for
1786  * all cases other than midway through a periodic split.  This will also update
1787  * start_active_frame.
1788  *
1789  * Since we _always_ keep start_active_frame as the start of the previous
1790  * transfer this is normally pretty easy: we just add our interval to
1791  * start_active_frame and we've got our answer.
1792  *
1793  * The tricks come into play if we miss.  In that case we'll look for the next
1794  * slot we can fit into.
1795  *
1796  * @hsotg:        The HCD state structure
1797  * @qh:           QH for the periodic transfer.
1798  * @frame_number: The current frame number.
1799  *
1800  * Return: number missed by (or 0 if we didn't miss).
1801  */
1802 static int dwc2_next_periodic_start(struct dwc2_hsotg *hsotg,
1803 				    struct dwc2_qh *qh, u16 frame_number)
1804 {
1805 	int missed = 0;
1806 	u16 interval = qh->host_interval;
1807 	u16 prev_frame_number = dwc2_frame_num_dec(frame_number, 1);
1808 
1809 	qh->start_active_frame = dwc2_frame_num_inc(qh->start_active_frame,
1810 						    interval);
1811 
1812 	/*
1813 	 * The dwc2_frame_num_gt() function used below won't work terribly well
1814 	 * with if we just incremented by a really large intervals since the
1815 	 * frame counter only goes to 0x3fff.  It's terribly unlikely that we
1816 	 * will have missed in this case anyway.  Just go to exit.  If we want
1817 	 * to try to do better we'll need to keep track of a bigger counter
1818 	 * somewhere in the driver and handle overflows.
1819 	 */
1820 	if (interval >= 0x1000)
1821 		goto exit;
1822 
1823 	/*
1824 	 * Test for misses, which is when it's too late to schedule.
1825 	 *
1826 	 * A few things to note:
1827 	 * - We compare against prev_frame_number since start_active_frame
1828 	 *   and next_active_frame are always 1 frame before we want things
1829 	 *   to be active and we assume we can still get scheduled in the
1830 	 *   current frame number.
1831 	 * - It's possible for start_active_frame (now incremented) to be
1832 	 *   next_active_frame if we got an EO MISS (even_odd miss) which
1833 	 *   basically means that we detected there wasn't enough time for
1834 	 *   the last packet and dwc2_hc_set_even_odd_frame() rescheduled us
1835 	 *   at the last second.  We want to make sure we don't schedule
1836 	 *   another transfer for the same frame.  My test webcam doesn't seem
1837 	 *   terribly upset by missing a transfer but really doesn't like when
1838 	 *   we do two transfers in the same frame.
1839 	 * - Some misses are expected.  Specifically, in order to work
1840 	 *   perfectly dwc2 really needs quite spectacular interrupt latency
1841 	 *   requirements.  It needs to be able to handle its interrupts
1842 	 *   completely within 125 us of them being asserted. That not only
1843 	 *   means that the dwc2 interrupt handler needs to be fast but it
1844 	 *   means that nothing else in the system has to block dwc2 for a long
1845 	 *   time.  We can help with the dwc2 parts of this, but it's hard to
1846 	 *   guarantee that a system will have interrupt latency < 125 us, so
1847 	 *   we have to be robust to some misses.
1848 	 */
1849 	if (qh->start_active_frame == qh->next_active_frame ||
1850 	    dwc2_frame_num_gt(prev_frame_number, qh->start_active_frame)) {
1851 		u16 ideal_start = qh->start_active_frame;
1852 		int periods_in_map;
1853 
1854 		/*
1855 		 * Adjust interval as per gcd with map size.
1856 		 * See pmap_schedule() for more details here.
1857 		 */
1858 		if (qh->do_split || qh->dev_speed == USB_SPEED_HIGH)
1859 			periods_in_map = DWC2_HS_SCHEDULE_UFRAMES;
1860 		else
1861 			periods_in_map = DWC2_LS_SCHEDULE_FRAMES;
1862 		interval = gcd(interval, periods_in_map);
1863 
1864 		do {
1865 			qh->start_active_frame = dwc2_frame_num_inc(
1866 				qh->start_active_frame, interval);
1867 		} while (dwc2_frame_num_gt(prev_frame_number,
1868 					   qh->start_active_frame));
1869 
1870 		missed = dwc2_frame_num_dec(qh->start_active_frame,
1871 					    ideal_start);
1872 	}
1873 
1874 exit:
1875 	qh->next_active_frame = qh->start_active_frame;
1876 
1877 	return missed;
1878 }
1879 
1880 /*
1881  * Deactivates a QH. For non-periodic QHs, removes the QH from the active
1882  * non-periodic schedule. The QH is added to the inactive non-periodic
1883  * schedule if any QTDs are still attached to the QH.
1884  *
1885  * For periodic QHs, the QH is removed from the periodic queued schedule. If
1886  * there are any QTDs still attached to the QH, the QH is added to either the
1887  * periodic inactive schedule or the periodic ready schedule and its next
1888  * scheduled frame is calculated. The QH is placed in the ready schedule if
1889  * the scheduled frame has been reached already. Otherwise it's placed in the
1890  * inactive schedule. If there are no QTDs attached to the QH, the QH is
1891  * completely removed from the periodic schedule.
1892  */
1893 void dwc2_hcd_qh_deactivate(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh,
1894 			    int sched_next_periodic_split)
1895 {
1896 	u16 old_frame = qh->next_active_frame;
1897 	u16 frame_number;
1898 	int missed;
1899 
1900 	if (dbg_qh(qh))
1901 		dev_vdbg(hsotg->dev, "%s()\n", __func__);
1902 
1903 	if (dwc2_qh_is_non_per(qh)) {
1904 		dwc2_hcd_qh_unlink(hsotg, qh);
1905 		if (!list_empty(&qh->qtd_list))
1906 			/* Add back to inactive non-periodic schedule */
1907 			dwc2_hcd_qh_add(hsotg, qh);
1908 		return;
1909 	}
1910 
1911 	/*
1912 	 * Use the real frame number rather than the cached value as of the
1913 	 * last SOF just to get us a little closer to reality.  Note that
1914 	 * means we don't actually know if we've already handled the SOF
1915 	 * interrupt for this frame.
1916 	 */
1917 	frame_number = dwc2_hcd_get_frame_number(hsotg);
1918 
1919 	if (sched_next_periodic_split)
1920 		missed = dwc2_next_for_periodic_split(hsotg, qh, frame_number);
1921 	else
1922 		missed = dwc2_next_periodic_start(hsotg, qh, frame_number);
1923 
1924 	dwc2_sch_vdbg(hsotg,
1925 		      "QH=%p next(%d) fn=%04x, sch=%04x=>%04x (%+d) miss=%d %s\n",
1926 		     qh, sched_next_periodic_split, frame_number, old_frame,
1927 		     qh->next_active_frame,
1928 		     dwc2_frame_num_dec(qh->next_active_frame, old_frame),
1929 		missed, missed ? "MISS" : "");
1930 
1931 	if (list_empty(&qh->qtd_list)) {
1932 		dwc2_hcd_qh_unlink(hsotg, qh);
1933 		return;
1934 	}
1935 
1936 	/*
1937 	 * Remove from periodic_sched_queued and move to
1938 	 * appropriate queue
1939 	 *
1940 	 * Note: we purposely use the frame_number from the "hsotg" structure
1941 	 * since we know SOF interrupt will handle future frames.
1942 	 */
1943 	if (dwc2_frame_num_le(qh->next_active_frame, hsotg->frame_number))
1944 		list_move_tail(&qh->qh_list_entry,
1945 			       &hsotg->periodic_sched_ready);
1946 	else
1947 		list_move_tail(&qh->qh_list_entry,
1948 			       &hsotg->periodic_sched_inactive);
1949 }
1950 
1951 /**
1952  * dwc2_hcd_qtd_init() - Initializes a QTD structure
1953  *
1954  * @qtd: The QTD to initialize
1955  * @urb: The associated URB
1956  */
1957 void dwc2_hcd_qtd_init(struct dwc2_qtd *qtd, struct dwc2_hcd_urb *urb)
1958 {
1959 	qtd->urb = urb;
1960 	if (dwc2_hcd_get_pipe_type(&urb->pipe_info) ==
1961 			USB_ENDPOINT_XFER_CONTROL) {
1962 		/*
1963 		 * The only time the QTD data toggle is used is on the data
1964 		 * phase of control transfers. This phase always starts with
1965 		 * DATA1.
1966 		 */
1967 		qtd->data_toggle = DWC2_HC_PID_DATA1;
1968 		qtd->control_phase = DWC2_CONTROL_SETUP;
1969 	}
1970 
1971 	/* Start split */
1972 	qtd->complete_split = 0;
1973 	qtd->isoc_split_pos = DWC2_HCSPLT_XACTPOS_ALL;
1974 	qtd->isoc_split_offset = 0;
1975 	qtd->in_process = 0;
1976 
1977 	/* Store the qtd ptr in the urb to reference the QTD */
1978 	urb->qtd = qtd;
1979 }
1980 
1981 /**
1982  * dwc2_hcd_qtd_add() - Adds a QTD to the QTD-list of a QH
1983  *			Caller must hold driver lock.
1984  *
1985  * @hsotg:        The DWC HCD structure
1986  * @qtd:          The QTD to add
1987  * @qh:           Queue head to add qtd to
1988  *
1989  * Return: 0 if successful, negative error code otherwise
1990  *
1991  * If the QH to which the QTD is added is not currently scheduled, it is placed
1992  * into the proper schedule based on its EP type.
1993  */
1994 int dwc2_hcd_qtd_add(struct dwc2_hsotg *hsotg, struct dwc2_qtd *qtd,
1995 		     struct dwc2_qh *qh)
1996 {
1997 	int retval;
1998 
1999 	if (unlikely(!qh)) {
2000 		dev_err(hsotg->dev, "%s: Invalid QH\n", __func__);
2001 		retval = -EINVAL;
2002 		goto fail;
2003 	}
2004 
2005 	retval = dwc2_hcd_qh_add(hsotg, qh);
2006 	if (retval)
2007 		goto fail;
2008 
2009 	qtd->qh = qh;
2010 	list_add_tail(&qtd->qtd_list_entry, &qh->qtd_list);
2011 
2012 	return 0;
2013 fail:
2014 	return retval;
2015 }
2016