xref: /openbmc/linux/drivers/usb/dwc2/hcd_queue.c (revision 8730046c)
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
81 	    && hsotg->periodic_channels < num_channels - 1) {
82 		status = 0;
83 	} else {
84 		dev_dbg(hsotg->dev,
85 			"%s: Total channels: %d, Periodic: %d, "
86 			"Non-periodic: %d\n", __func__, num_channels,
87 			hsotg->periodic_channels, hsotg->non_periodic_channels);
88 		status = -ENOSPC;
89 	}
90 
91 	return status;
92 }
93 
94 /**
95  * dwc2_check_periodic_bandwidth() - Checks that there is sufficient bandwidth
96  * for the specified QH in the periodic schedule
97  *
98  * @hsotg: The HCD state structure for the DWC OTG controller
99  * @qh:    QH containing periodic bandwidth required
100  *
101  * Return: 0 if successful, negative error code otherwise
102  *
103  * For simplicity, this calculation assumes that all the transfers in the
104  * periodic schedule may occur in the same (micro)frame
105  */
106 static int dwc2_check_periodic_bandwidth(struct dwc2_hsotg *hsotg,
107 					 struct dwc2_qh *qh)
108 {
109 	int status;
110 	s16 max_claimed_usecs;
111 
112 	status = 0;
113 
114 	if (qh->dev_speed == USB_SPEED_HIGH || qh->do_split) {
115 		/*
116 		 * High speed mode
117 		 * Max periodic usecs is 80% x 125 usec = 100 usec
118 		 */
119 		max_claimed_usecs = 100 - qh->host_us;
120 	} else {
121 		/*
122 		 * Full speed mode
123 		 * Max periodic usecs is 90% x 1000 usec = 900 usec
124 		 */
125 		max_claimed_usecs = 900 - qh->host_us;
126 	}
127 
128 	if (hsotg->periodic_usecs > max_claimed_usecs) {
129 		dev_err(hsotg->dev,
130 			"%s: already claimed usecs %d, required usecs %d\n",
131 			__func__, hsotg->periodic_usecs, qh->host_us);
132 		status = -ENOSPC;
133 	}
134 
135 	return status;
136 }
137 
138 /**
139  * pmap_schedule() - Schedule time in a periodic bitmap (pmap).
140  *
141  * @map:             The bitmap representing the schedule; will be updated
142  *                   upon success.
143  * @bits_per_period: The schedule represents several periods.  This is how many
144  *                   bits are in each period.  It's assumed that the beginning
145  *                   of the schedule will repeat after its end.
146  * @periods_in_map:  The number of periods in the schedule.
147  * @num_bits:        The number of bits we need per period we want to reserve
148  *                   in this function call.
149  * @interval:        How often we need to be scheduled for the reservation this
150  *                   time.  1 means every period.  2 means every other period.
151  *                   ...you get the picture?
152  * @start:           The bit number to start at.  Normally 0.  Must be within
153  *                   the interval or we return failure right away.
154  * @only_one_period: Normally we'll allow picking a start anywhere within the
155  *                   first interval, since we can still make all repetition
156  *                   requirements by doing that.  However, if you pass true
157  *                   here then we'll return failure if we can't fit within
158  *                   the period that "start" is in.
159  *
160  * The idea here is that we want to schedule time for repeating events that all
161  * want the same resource.  The resource is divided into fixed-sized periods
162  * and the events want to repeat every "interval" periods.  The schedule
163  * granularity is one bit.
164  *
165  * To keep things "simple", we'll represent our schedule with a bitmap that
166  * contains a fixed number of periods.  This gets rid of a lot of complexity
167  * but does mean that we need to handle things specially (and non-ideally) if
168  * the number of the periods in the schedule doesn't match well with the
169  * intervals that we're trying to schedule.
170  *
171  * Here's an explanation of the scheme we'll implement, assuming 8 periods.
172  * - If interval is 1, we need to take up space in each of the 8
173  *   periods we're scheduling.  Easy.
174  * - If interval is 2, we need to take up space in half of the
175  *   periods.  Again, easy.
176  * - If interval is 3, we actually need to fall back to interval 1.
177  *   Why?  Because we might need time in any period.  AKA for the
178  *   first 8 periods, we'll be in slot 0, 3, 6.  Then we'll be
179  *   in slot 1, 4, 7.  Then we'll be in 2, 5.  Then we'll be back to
180  *   0, 3, and 6.  Since we could be in any frame we need to reserve
181  *   for all of them.  Sucks, but that's what you gotta do.  Note that
182  *   if we were instead scheduling 8 * 3 = 24 we'd do much better, but
183  *   then we need more memory and time to do scheduling.
184  * - If interval is 4, easy.
185  * - If interval is 5, we again need interval 1.  The schedule will be
186  *   0, 5, 2, 7, 4, 1, 6, 3, 0
187  * - If interval is 6, we need interval 2.  0, 6, 4, 2.
188  * - If interval is 7, we need interval 1.
189  * - If interval is 8, we need interval 8.
190  *
191  * If you do the math, you'll see that we need to pretend that interval is
192  * equal to the greatest_common_divisor(interval, periods_in_map).
193  *
194  * Note that at the moment this function tends to front-pack the schedule.
195  * In some cases that's really non-ideal (it's hard to schedule things that
196  * need to repeat every period).  In other cases it's perfect (you can easily
197  * schedule bigger, less often repeating things).
198  *
199  * Here's the algorithm in action (8 periods, 5 bits per period):
200  *  |**   |     |**   |     |**   |     |**   |     |   OK 2 bits, intv 2 at 0
201  *  |*****|  ***|*****|  ***|*****|  ***|*****|  ***|   OK 3 bits, intv 3 at 2
202  *  |*****|* ***|*****|  ***|*****|* ***|*****|  ***|   OK 1 bits, intv 4 at 5
203  *  |**   |*    |**   |     |**   |*    |**   |     | Remv 3 bits, intv 3 at 2
204  *  |***  |*    |***  |     |***  |*    |***  |     |   OK 1 bits, intv 6 at 2
205  *  |**** |*  * |**** |   * |**** |*  * |**** |   * |   OK 1 bits, intv 1 at 3
206  *  |**** |**** |**** | *** |**** |**** |**** | *** |   OK 2 bits, intv 2 at 6
207  *  |*****|*****|*****| ****|*****|*****|*****| ****|   OK 1 bits, intv 1 at 4
208  *  |*****|*****|*****| ****|*****|*****|*****| ****| FAIL 1 bits, intv 1
209  *  |  ***|*****|  ***| ****|  ***|*****|  ***| ****| Remv 2 bits, intv 2 at 0
210  *  |  ***| ****|  ***| ****|  ***| ****|  ***| ****| Remv 1 bits, intv 4 at 5
211  *  |   **| ****|   **| ****|   **| ****|   **| ****| Remv 1 bits, intv 6 at 2
212  *  |    *| ** *|    *| ** *|    *| ** *|    *| ** *| Remv 1 bits, intv 1 at 3
213  *  |    *|    *|    *|    *|    *|    *|    *|    *| Remv 2 bits, intv 2 at 6
214  *  |     |     |     |     |     |     |     |     | Remv 1 bits, intv 1 at 4
215  *  |**   |     |**   |     |**   |     |**   |     |   OK 2 bits, intv 2 at 0
216  *  |***  |     |**   |     |***  |     |**   |     |   OK 1 bits, intv 4 at 2
217  *  |*****|     |** **|     |*****|     |** **|     |   OK 2 bits, intv 2 at 3
218  *  |*****|*    |** **|     |*****|*    |** **|     |   OK 1 bits, intv 4 at 5
219  *  |*****|***  |** **| **  |*****|***  |** **| **  |   OK 2 bits, intv 2 at 6
220  *  |*****|*****|** **| ****|*****|*****|** **| ****|   OK 2 bits, intv 2 at 8
221  *  |*****|*****|*****| ****|*****|*****|*****| ****|   OK 1 bits, intv 4 at 12
222  *
223  * This function is pretty generic and could be easily abstracted if anything
224  * needed similar scheduling.
225  *
226  * Returns either -ENOSPC or a >= 0 start bit which should be passed to the
227  * unschedule routine.  The map bitmap will be updated on a non-error result.
228  */
229 static int pmap_schedule(unsigned long *map, int bits_per_period,
230 			 int periods_in_map, int num_bits,
231 			 int interval, int start, bool only_one_period)
232 {
233 	int interval_bits;
234 	int to_reserve;
235 	int first_end;
236 	int i;
237 
238 	if (num_bits > bits_per_period)
239 		return -ENOSPC;
240 
241 	/* Adjust interval as per description */
242 	interval = gcd(interval, periods_in_map);
243 
244 	interval_bits = bits_per_period * interval;
245 	to_reserve = periods_in_map / interval;
246 
247 	/* If start has gotten us past interval then we can't schedule */
248 	if (start >= interval_bits)
249 		return -ENOSPC;
250 
251 	if (only_one_period)
252 		/* Must fit within same period as start; end at begin of next */
253 		first_end = (start / bits_per_period + 1) * bits_per_period;
254 	else
255 		/* Can fit anywhere in the first interval */
256 		first_end = interval_bits;
257 
258 	/*
259 	 * We'll try to pick the first repetition, then see if that time
260 	 * is free for each of the subsequent repetitions.  If it's not
261 	 * we'll adjust the start time for the next search of the first
262 	 * repetition.
263 	 */
264 	while (start + num_bits <= first_end) {
265 		int end;
266 
267 		/* Need to stay within this period */
268 		end = (start / bits_per_period + 1) * bits_per_period;
269 
270 		/* Look for num_bits us in this microframe starting at start */
271 		start = bitmap_find_next_zero_area(map, end, start, num_bits,
272 						   0);
273 
274 		/*
275 		 * We should get start >= end if we fail.  We might be
276 		 * able to check the next microframe depending on the
277 		 * interval, so continue on (start already updated).
278 		 */
279 		if (start >= end) {
280 			start = end;
281 			continue;
282 		}
283 
284 		/* At this point we have a valid point for first one */
285 		for (i = 1; i < to_reserve; i++) {
286 			int ith_start = start + interval_bits * i;
287 			int ith_end = end + interval_bits * i;
288 			int ret;
289 
290 			/* Use this as a dumb "check if bits are 0" */
291 			ret = bitmap_find_next_zero_area(
292 				map, ith_start + num_bits, ith_start, num_bits,
293 				0);
294 
295 			/* We got the right place, continue checking */
296 			if (ret == ith_start)
297 				continue;
298 
299 			/* Move start up for next time and exit for loop */
300 			ith_start = bitmap_find_next_zero_area(
301 				map, ith_end, ith_start, num_bits, 0);
302 			if (ith_start >= ith_end)
303 				/* Need a while new period next time */
304 				start = end;
305 			else
306 				start = ith_start - interval_bits * i;
307 			break;
308 		}
309 
310 		/* If didn't exit the for loop with a break, we have success */
311 		if (i == to_reserve)
312 			break;
313 	}
314 
315 	if (start + num_bits > first_end)
316 		return -ENOSPC;
317 
318 	for (i = 0; i < to_reserve; i++) {
319 		int ith_start = start + interval_bits * i;
320 
321 		bitmap_set(map, ith_start, num_bits);
322 	}
323 
324 	return start;
325 }
326 
327 /**
328  * pmap_unschedule() - Undo work done by pmap_schedule()
329  *
330  * @map:             See pmap_schedule().
331  * @bits_per_period: See pmap_schedule().
332  * @periods_in_map:  See pmap_schedule().
333  * @num_bits:        The number of bits that was passed to schedule.
334  * @interval:        The interval that was passed to schedule.
335  * @start:           The return value from pmap_schedule().
336  */
337 static void pmap_unschedule(unsigned long *map, int bits_per_period,
338 			    int periods_in_map, int num_bits,
339 			    int interval, int start)
340 {
341 	int interval_bits;
342 	int to_release;
343 	int i;
344 
345 	/* Adjust interval as per description in pmap_schedule() */
346 	interval = gcd(interval, periods_in_map);
347 
348 	interval_bits = bits_per_period * interval;
349 	to_release = periods_in_map / interval;
350 
351 	for (i = 0; i < to_release; i++) {
352 		int ith_start = start + interval_bits * i;
353 
354 		bitmap_clear(map, ith_start, num_bits);
355 	}
356 }
357 
358 /**
359  * dwc2_get_ls_map() - Get the map used for the given qh
360  *
361  * @hsotg: The HCD state structure for the DWC OTG controller.
362  * @qh:    QH for the periodic transfer.
363  *
364  * We'll always get the periodic map out of our TT.  Note that even if we're
365  * running the host straight in low speed / full speed mode it appears as if
366  * a TT is allocated for us, so we'll use it.  If that ever changes we can
367  * add logic here to get a map out of "hsotg" if !qh->do_split.
368  *
369  * Returns: the map or NULL if a map couldn't be found.
370  */
371 static unsigned long *dwc2_get_ls_map(struct dwc2_hsotg *hsotg,
372 				      struct dwc2_qh *qh)
373 {
374 	unsigned long *map;
375 
376 	/* Don't expect to be missing a TT and be doing low speed scheduling */
377 	if (WARN_ON(!qh->dwc_tt))
378 		return NULL;
379 
380 	/* Get the map and adjust if this is a multi_tt hub */
381 	map = qh->dwc_tt->periodic_bitmaps;
382 	if (qh->dwc_tt->usb_tt->multi)
383 		map += DWC2_ELEMENTS_PER_LS_BITMAP * qh->ttport;
384 
385 	return map;
386 }
387 
388 #ifdef DWC2_PRINT_SCHEDULE
389 /*
390  * cat_printf() - A printf() + strcat() helper
391  *
392  * This is useful for concatenating a bunch of strings where each string is
393  * constructed using printf.
394  *
395  * @buf:   The destination buffer; will be updated to point after the printed
396  *         data.
397  * @size:  The number of bytes in the buffer (includes space for '\0').
398  * @fmt:   The format for printf.
399  * @...:   The args for printf.
400  */
401 static __printf(3, 4)
402 void cat_printf(char **buf, size_t *size, const char *fmt, ...)
403 {
404 	va_list args;
405 	int i;
406 
407 	if (*size == 0)
408 		return;
409 
410 	va_start(args, fmt);
411 	i = vsnprintf(*buf, *size, fmt, args);
412 	va_end(args);
413 
414 	if (i >= *size) {
415 		(*buf)[*size - 1] = '\0';
416 		*buf += *size;
417 		*size = 0;
418 	} else {
419 		*buf += i;
420 		*size -= i;
421 	}
422 }
423 
424 /*
425  * pmap_print() - Print the given periodic map
426  *
427  * Will attempt to print out the periodic schedule.
428  *
429  * @map:             See pmap_schedule().
430  * @bits_per_period: See pmap_schedule().
431  * @periods_in_map:  See pmap_schedule().
432  * @period_name:     The name of 1 period, like "uFrame"
433  * @units:           The name of the units, like "us".
434  * @print_fn:        The function to call for printing.
435  * @print_data:      Opaque data to pass to the print function.
436  */
437 static void pmap_print(unsigned long *map, int bits_per_period,
438 		       int periods_in_map, const char *period_name,
439 		       const char *units,
440 		       void (*print_fn)(const char *str, void *data),
441 		       void *print_data)
442 {
443 	int period;
444 
445 	for (period = 0; period < periods_in_map; period++) {
446 		char tmp[64];
447 		char *buf = tmp;
448 		size_t buf_size = sizeof(tmp);
449 		int period_start = period * bits_per_period;
450 		int period_end = period_start + bits_per_period;
451 		int start = 0;
452 		int count = 0;
453 		bool printed = false;
454 		int i;
455 
456 		for (i = period_start; i < period_end + 1; i++) {
457 			/* Handle case when ith bit is set */
458 			if (i < period_end &&
459 			    bitmap_find_next_zero_area(map, i + 1,
460 						       i, 1, 0) != i) {
461 				if (count == 0)
462 					start = i - period_start;
463 				count++;
464 				continue;
465 			}
466 
467 			/* ith bit isn't set; don't care if count == 0 */
468 			if (count == 0)
469 				continue;
470 
471 			if (!printed)
472 				cat_printf(&buf, &buf_size, "%s %d: ",
473 					   period_name, period);
474 			else
475 				cat_printf(&buf, &buf_size, ", ");
476 			printed = true;
477 
478 			cat_printf(&buf, &buf_size, "%d %s -%3d %s", start,
479 				   units, start + count - 1, units);
480 			count = 0;
481 		}
482 
483 		if (printed)
484 			print_fn(tmp, print_data);
485 	}
486 }
487 
488 
489 struct dwc2_qh_print_data {
490 	struct dwc2_hsotg *hsotg;
491 	struct dwc2_qh *qh;
492 };
493 
494 /**
495  * dwc2_qh_print() - Helper function for dwc2_qh_schedule_print()
496  *
497  * @str:  The string to print
498  * @data: A pointer to a struct dwc2_qh_print_data
499  */
500 static void dwc2_qh_print(const char *str, void *data)
501 {
502 	struct dwc2_qh_print_data *print_data = data;
503 
504 	dwc2_sch_dbg(print_data->hsotg, "QH=%p ...%s\n", print_data->qh, str);
505 }
506 
507 /**
508  * dwc2_qh_schedule_print() - Print the periodic schedule
509  *
510  * @hsotg: The HCD state structure for the DWC OTG controller.
511  * @qh:    QH to print.
512  */
513 static void dwc2_qh_schedule_print(struct dwc2_hsotg *hsotg,
514 				   struct dwc2_qh *qh)
515 {
516 	struct dwc2_qh_print_data print_data = { hsotg, qh };
517 	int i;
518 
519 	/*
520 	 * The printing functions are quite slow and inefficient.
521 	 * If we don't have tracing turned on, don't run unless the special
522 	 * define is turned on.
523 	 */
524 
525 	if (qh->schedule_low_speed) {
526 		unsigned long *map = dwc2_get_ls_map(hsotg, qh);
527 
528 		dwc2_sch_dbg(hsotg, "QH=%p LS/FS trans: %d=>%d us @ %d us",
529 			     qh, qh->device_us,
530 			     DWC2_ROUND_US_TO_SLICE(qh->device_us),
531 			     DWC2_US_PER_SLICE * qh->ls_start_schedule_slice);
532 
533 		if (map) {
534 			dwc2_sch_dbg(hsotg,
535 				     "QH=%p Whole low/full speed map %p now:\n",
536 				     qh, map);
537 			pmap_print(map, DWC2_LS_PERIODIC_SLICES_PER_FRAME,
538 				   DWC2_LS_SCHEDULE_FRAMES, "Frame ", "slices",
539 				   dwc2_qh_print, &print_data);
540 		}
541 	}
542 
543 	for (i = 0; i < qh->num_hs_transfers; i++) {
544 		struct dwc2_hs_transfer_time *trans_time = qh->hs_transfers + i;
545 		int uframe = trans_time->start_schedule_us /
546 			     DWC2_HS_PERIODIC_US_PER_UFRAME;
547 		int rel_us = trans_time->start_schedule_us %
548 			     DWC2_HS_PERIODIC_US_PER_UFRAME;
549 
550 		dwc2_sch_dbg(hsotg,
551 			     "QH=%p HS trans #%d: %d us @ uFrame %d + %d us\n",
552 			     qh, i, trans_time->duration_us, uframe, rel_us);
553 	}
554 	if (qh->num_hs_transfers) {
555 		dwc2_sch_dbg(hsotg, "QH=%p Whole high speed map now:\n", qh);
556 		pmap_print(hsotg->hs_periodic_bitmap,
557 			   DWC2_HS_PERIODIC_US_PER_UFRAME,
558 			   DWC2_HS_SCHEDULE_UFRAMES, "uFrame", "us",
559 			   dwc2_qh_print, &print_data);
560 	}
561 	return;
562 }
563 #else
564 static inline void dwc2_qh_schedule_print(struct dwc2_hsotg *hsotg,
565 					  struct dwc2_qh *qh) {};
566 #endif
567 
568 /**
569  * dwc2_ls_pmap_schedule() - Schedule a low speed QH
570  *
571  * @hsotg:        The HCD state structure for the DWC OTG controller.
572  * @qh:           QH for the periodic transfer.
573  * @search_slice: We'll start trying to schedule at the passed slice.
574  *                Remember that slices are the units of the low speed
575  *                schedule (think 25us or so).
576  *
577  * Wraps pmap_schedule() with the right parameters for low speed scheduling.
578  *
579  * Normally we schedule low speed devices on the map associated with the TT.
580  *
581  * Returns: 0 for success or an error code.
582  */
583 static int dwc2_ls_pmap_schedule(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh,
584 				 int search_slice)
585 {
586 	int slices = DIV_ROUND_UP(qh->device_us, DWC2_US_PER_SLICE);
587 	unsigned long *map = dwc2_get_ls_map(hsotg, qh);
588 	int slice;
589 
590 	if (map == NULL)
591 		return -EINVAL;
592 
593 	/*
594 	 * Schedule on the proper low speed map with our low speed scheduling
595 	 * parameters.  Note that we use the "device_interval" here since
596 	 * we want the low speed interval and the only way we'd be in this
597 	 * function is if the device is low speed.
598 	 *
599 	 * If we happen to be doing low speed and high speed scheduling for the
600 	 * same transaction (AKA we have a split) we always do low speed first.
601 	 * That means we can always pass "false" for only_one_period (that
602 	 * parameters is only useful when we're trying to get one schedule to
603 	 * match what we already planned in the other schedule).
604 	 */
605 	slice = pmap_schedule(map, DWC2_LS_PERIODIC_SLICES_PER_FRAME,
606 			      DWC2_LS_SCHEDULE_FRAMES, slices,
607 			      qh->device_interval, search_slice, false);
608 
609 	if (slice < 0)
610 		return slice;
611 
612 	qh->ls_start_schedule_slice = slice;
613 	return 0;
614 }
615 
616 /**
617  * dwc2_ls_pmap_unschedule() - Undo work done by dwc2_ls_pmap_schedule()
618  *
619  * @hsotg:       The HCD state structure for the DWC OTG controller.
620  * @qh:          QH for the periodic transfer.
621  */
622 static void dwc2_ls_pmap_unschedule(struct dwc2_hsotg *hsotg,
623 				    struct dwc2_qh *qh)
624 {
625 	int slices = DIV_ROUND_UP(qh->device_us, DWC2_US_PER_SLICE);
626 	unsigned long *map = dwc2_get_ls_map(hsotg, qh);
627 
628 	/* Schedule should have failed, so no worries about no error code */
629 	if (map == NULL)
630 		return;
631 
632 	pmap_unschedule(map, DWC2_LS_PERIODIC_SLICES_PER_FRAME,
633 			DWC2_LS_SCHEDULE_FRAMES, slices, qh->device_interval,
634 			qh->ls_start_schedule_slice);
635 }
636 
637 /**
638  * dwc2_hs_pmap_schedule - Schedule in the main high speed schedule
639  *
640  * This will schedule something on the main dwc2 schedule.
641  *
642  * We'll start looking in qh->hs_transfers[index].start_schedule_us.  We'll
643  * update this with the result upon success.  We also use the duration from
644  * the same structure.
645  *
646  * @hsotg:           The HCD state structure for the DWC OTG controller.
647  * @qh:              QH for the periodic transfer.
648  * @only_one_period: If true we will limit ourselves to just looking at
649  *                   one period (aka one 100us chunk).  This is used if we have
650  *                   already scheduled something on the low speed schedule and
651  *                   need to find something that matches on the high speed one.
652  * @index:           The index into qh->hs_transfers that we're working with.
653  *
654  * Returns: 0 for success or an error code.  Upon success the
655  *          dwc2_hs_transfer_time specified by "index" will be updated.
656  */
657 static int dwc2_hs_pmap_schedule(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh,
658 				 bool only_one_period, int index)
659 {
660 	struct dwc2_hs_transfer_time *trans_time = qh->hs_transfers + index;
661 	int us;
662 
663 	us = pmap_schedule(hsotg->hs_periodic_bitmap,
664 			   DWC2_HS_PERIODIC_US_PER_UFRAME,
665 			   DWC2_HS_SCHEDULE_UFRAMES, trans_time->duration_us,
666 			   qh->host_interval, trans_time->start_schedule_us,
667 			   only_one_period);
668 
669 	if (us < 0)
670 		return us;
671 
672 	trans_time->start_schedule_us = us;
673 	return 0;
674 }
675 
676 /**
677  * dwc2_ls_pmap_unschedule() - Undo work done by dwc2_hs_pmap_schedule()
678  *
679  * @hsotg:       The HCD state structure for the DWC OTG controller.
680  * @qh:          QH for the periodic transfer.
681  */
682 static void dwc2_hs_pmap_unschedule(struct dwc2_hsotg *hsotg,
683 				    struct dwc2_qh *qh, int index)
684 {
685 	struct dwc2_hs_transfer_time *trans_time = qh->hs_transfers + index;
686 
687 	pmap_unschedule(hsotg->hs_periodic_bitmap,
688 			DWC2_HS_PERIODIC_US_PER_UFRAME,
689 			DWC2_HS_SCHEDULE_UFRAMES, trans_time->duration_us,
690 			qh->host_interval, trans_time->start_schedule_us);
691 }
692 
693 /**
694  * dwc2_uframe_schedule_split - Schedule a QH for a periodic split xfer.
695  *
696  * This is the most complicated thing in USB.  We have to find matching time
697  * in both the global high speed schedule for the port and the low speed
698  * schedule for the TT associated with the given device.
699  *
700  * Being here means that the host must be running in high speed mode and the
701  * device is in low or full speed mode (and behind a hub).
702  *
703  * @hsotg:       The HCD state structure for the DWC OTG controller.
704  * @qh:          QH for the periodic transfer.
705  */
706 static int dwc2_uframe_schedule_split(struct dwc2_hsotg *hsotg,
707 				      struct dwc2_qh *qh)
708 {
709 	int bytecount = dwc2_hb_mult(qh->maxp) * dwc2_max_packet(qh->maxp);
710 	int ls_search_slice;
711 	int err = 0;
712 	int host_interval_in_sched;
713 
714 	/*
715 	 * The interval (how often to repeat) in the actual host schedule.
716 	 * See pmap_schedule() for gcd() explanation.
717 	 */
718 	host_interval_in_sched = gcd(qh->host_interval,
719 				     DWC2_HS_SCHEDULE_UFRAMES);
720 
721 	/*
722 	 * We always try to find space in the low speed schedule first, then
723 	 * try to find high speed time that matches.  If we don't, we'll bump
724 	 * up the place we start searching in the low speed schedule and try
725 	 * again.  To start we'll look right at the beginning of the low speed
726 	 * schedule.
727 	 *
728 	 * Note that this will tend to front-load the high speed schedule.
729 	 * We may eventually want to try to avoid this by either considering
730 	 * both schedules together or doing some sort of round robin.
731 	 */
732 	ls_search_slice = 0;
733 
734 	while (ls_search_slice < DWC2_LS_SCHEDULE_SLICES) {
735 		int start_s_uframe;
736 		int ssplit_s_uframe;
737 		int second_s_uframe;
738 		int rel_uframe;
739 		int first_count;
740 		int middle_count;
741 		int end_count;
742 		int first_data_bytes;
743 		int other_data_bytes;
744 		int i;
745 
746 		if (qh->schedule_low_speed) {
747 			err = dwc2_ls_pmap_schedule(hsotg, qh, ls_search_slice);
748 
749 			/*
750 			 * If we got an error here there's no other magic we
751 			 * can do, so bail.  All the looping above is only
752 			 * helpful to redo things if we got a low speed slot
753 			 * and then couldn't find a matching high speed slot.
754 			 */
755 			if (err)
756 				return err;
757 		} else {
758 			/* Must be missing the tt structure?  Why? */
759 			WARN_ON_ONCE(1);
760 		}
761 
762 		/*
763 		 * This will give us a number 0 - 7 if
764 		 * DWC2_LS_SCHEDULE_FRAMES == 1, or 0 - 15 if == 2, or ...
765 		 */
766 		start_s_uframe = qh->ls_start_schedule_slice /
767 				 DWC2_SLICES_PER_UFRAME;
768 
769 		/* Get a number that's always 0 - 7 */
770 		rel_uframe = (start_s_uframe % 8);
771 
772 		/*
773 		 * If we were going to start in uframe 7 then we would need to
774 		 * issue a start split in uframe 6, which spec says is not OK.
775 		 * Move on to the next full frame (assuming there is one).
776 		 *
777 		 * See 11.18.4 Host Split Transaction Scheduling Requirements
778 		 * bullet 1.
779 		 */
780 		if (rel_uframe == 7) {
781 			if (qh->schedule_low_speed)
782 				dwc2_ls_pmap_unschedule(hsotg, qh);
783 			ls_search_slice =
784 				(qh->ls_start_schedule_slice /
785 				 DWC2_LS_PERIODIC_SLICES_PER_FRAME + 1) *
786 				DWC2_LS_PERIODIC_SLICES_PER_FRAME;
787 			continue;
788 		}
789 
790 		/*
791 		 * For ISOC in:
792 		 * - start split            (frame -1)
793 		 * - complete split w/ data (frame +1)
794 		 * - complete split w/ data (frame +2)
795 		 * - ...
796 		 * - complete split w/ data (frame +num_data_packets)
797 		 * - complete split w/ data (frame +num_data_packets+1)
798 		 * - complete split w/ data (frame +num_data_packets+2, max 8)
799 		 *   ...though if frame was "0" then max is 7...
800 		 *
801 		 * For ISOC out we might need to do:
802 		 * - start split w/ data    (frame -1)
803 		 * - start split w/ data    (frame +0)
804 		 * - ...
805 		 * - start split w/ data    (frame +num_data_packets-2)
806 		 *
807 		 * For INTERRUPT in we might need to do:
808 		 * - start split            (frame -1)
809 		 * - complete split w/ data (frame +1)
810 		 * - complete split w/ data (frame +2)
811 		 * - complete split w/ data (frame +3, max 8)
812 		 *
813 		 * For INTERRUPT out we might need to do:
814 		 * - start split w/ data    (frame -1)
815 		 * - complete split         (frame +1)
816 		 * - complete split         (frame +2)
817 		 * - complete split         (frame +3, max 8)
818 		 *
819 		 * Start adjusting!
820 		 */
821 		ssplit_s_uframe = (start_s_uframe +
822 				   host_interval_in_sched - 1) %
823 				  host_interval_in_sched;
824 		if (qh->ep_type == USB_ENDPOINT_XFER_ISOC && !qh->ep_is_in)
825 			second_s_uframe = start_s_uframe;
826 		else
827 			second_s_uframe = start_s_uframe + 1;
828 
829 		/* First data transfer might not be all 188 bytes. */
830 		first_data_bytes = 188 -
831 			DIV_ROUND_UP(188 * (qh->ls_start_schedule_slice %
832 					    DWC2_SLICES_PER_UFRAME),
833 				     DWC2_SLICES_PER_UFRAME);
834 		if (first_data_bytes > bytecount)
835 			first_data_bytes = bytecount;
836 		other_data_bytes = bytecount - first_data_bytes;
837 
838 		/*
839 		 * For now, skip OUT xfers where first xfer is partial
840 		 *
841 		 * Main dwc2 code assumes:
842 		 * - INT transfers never get split in two.
843 		 * - ISOC transfers can always transfer 188 bytes the first
844 		 *   time.
845 		 *
846 		 * Until that code is fixed, try again if the first transfer
847 		 * couldn't transfer everything.
848 		 *
849 		 * This code can be removed if/when the rest of dwc2 handles
850 		 * the above cases.  Until it's fixed we just won't be able
851 		 * to schedule quite as tightly.
852 		 */
853 		if (!qh->ep_is_in &&
854 		    (first_data_bytes != min_t(int, 188, bytecount))) {
855 			dwc2_sch_dbg(hsotg,
856 				     "QH=%p avoiding broken 1st xfer (%d, %d)\n",
857 				     qh, first_data_bytes, bytecount);
858 			if (qh->schedule_low_speed)
859 				dwc2_ls_pmap_unschedule(hsotg, qh);
860 			ls_search_slice = (start_s_uframe + 1) *
861 				DWC2_SLICES_PER_UFRAME;
862 			continue;
863 		}
864 
865 		/* Start by assuming transfers for the bytes */
866 		qh->num_hs_transfers = 1 + DIV_ROUND_UP(other_data_bytes, 188);
867 
868 		/*
869 		 * Everything except ISOC OUT has extra transfers.  Rules are
870 		 * complicated.  See 11.18.4 Host Split Transaction Scheduling
871 		 * Requirements bullet 3.
872 		 */
873 		if (qh->ep_type == USB_ENDPOINT_XFER_INT) {
874 			if (rel_uframe == 6)
875 				qh->num_hs_transfers += 2;
876 			else
877 				qh->num_hs_transfers += 3;
878 
879 			if (qh->ep_is_in) {
880 				/*
881 				 * First is start split, middle/end is data.
882 				 * Allocate full data bytes for all data.
883 				 */
884 				first_count = 4;
885 				middle_count = bytecount;
886 				end_count = bytecount;
887 			} else {
888 				/*
889 				 * First is data, middle/end is complete.
890 				 * First transfer and second can have data.
891 				 * Rest should just have complete split.
892 				 */
893 				first_count = first_data_bytes;
894 				middle_count = max_t(int, 4, other_data_bytes);
895 				end_count = 4;
896 			}
897 		} else {
898 			if (qh->ep_is_in) {
899 				int last;
900 
901 				/* Account for the start split */
902 				qh->num_hs_transfers++;
903 
904 				/* Calculate "L" value from spec */
905 				last = rel_uframe + qh->num_hs_transfers + 1;
906 
907 				/* Start with basic case */
908 				if (last <= 6)
909 					qh->num_hs_transfers += 2;
910 				else
911 					qh->num_hs_transfers += 1;
912 
913 				/* Adjust downwards */
914 				if (last >= 6 && rel_uframe == 0)
915 					qh->num_hs_transfers--;
916 
917 				/* 1st = start; rest can contain data */
918 				first_count = 4;
919 				middle_count = min_t(int, 188, bytecount);
920 				end_count = middle_count;
921 			} else {
922 				/* All contain data, last might be smaller */
923 				first_count = first_data_bytes;
924 				middle_count = min_t(int, 188,
925 						     other_data_bytes);
926 				end_count = other_data_bytes % 188;
927 			}
928 		}
929 
930 		/* Assign durations per uFrame */
931 		qh->hs_transfers[0].duration_us = HS_USECS_ISO(first_count);
932 		for (i = 1; i < qh->num_hs_transfers - 1; i++)
933 			qh->hs_transfers[i].duration_us =
934 				HS_USECS_ISO(middle_count);
935 		if (qh->num_hs_transfers > 1)
936 			qh->hs_transfers[qh->num_hs_transfers - 1].duration_us =
937 				HS_USECS_ISO(end_count);
938 
939 		/*
940 		 * Assign start us.  The call below to dwc2_hs_pmap_schedule()
941 		 * will start with these numbers but may adjust within the same
942 		 * microframe.
943 		 */
944 		qh->hs_transfers[0].start_schedule_us =
945 			ssplit_s_uframe * DWC2_HS_PERIODIC_US_PER_UFRAME;
946 		for (i = 1; i < qh->num_hs_transfers; i++)
947 			qh->hs_transfers[i].start_schedule_us =
948 				((second_s_uframe + i - 1) %
949 				 DWC2_HS_SCHEDULE_UFRAMES) *
950 				DWC2_HS_PERIODIC_US_PER_UFRAME;
951 
952 		/* Try to schedule with filled in hs_transfers above */
953 		for (i = 0; i < qh->num_hs_transfers; i++) {
954 			err = dwc2_hs_pmap_schedule(hsotg, qh, true, i);
955 			if (err)
956 				break;
957 		}
958 
959 		/* If we scheduled all w/out breaking out then we're all good */
960 		if (i == qh->num_hs_transfers)
961 			break;
962 
963 		for (; i >= 0; i--)
964 			dwc2_hs_pmap_unschedule(hsotg, qh, i);
965 
966 		if (qh->schedule_low_speed)
967 			dwc2_ls_pmap_unschedule(hsotg, qh);
968 
969 		/* Try again starting in the next microframe */
970 		ls_search_slice = (start_s_uframe + 1) * DWC2_SLICES_PER_UFRAME;
971 	}
972 
973 	if (ls_search_slice >= DWC2_LS_SCHEDULE_SLICES)
974 		return -ENOSPC;
975 
976 	return 0;
977 }
978 
979 /**
980  * dwc2_uframe_schedule_hs - Schedule a QH for a periodic high speed xfer.
981  *
982  * Basically this just wraps dwc2_hs_pmap_schedule() to provide a clean
983  * interface.
984  *
985  * @hsotg:       The HCD state structure for the DWC OTG controller.
986  * @qh:          QH for the periodic transfer.
987  */
988 static int dwc2_uframe_schedule_hs(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh)
989 {
990 	/* In non-split host and device time are the same */
991 	WARN_ON(qh->host_us != qh->device_us);
992 	WARN_ON(qh->host_interval != qh->device_interval);
993 	WARN_ON(qh->num_hs_transfers != 1);
994 
995 	/* We'll have one transfer; init start to 0 before calling scheduler */
996 	qh->hs_transfers[0].start_schedule_us = 0;
997 	qh->hs_transfers[0].duration_us = qh->host_us;
998 
999 	return dwc2_hs_pmap_schedule(hsotg, qh, false, 0);
1000 }
1001 
1002 /**
1003  * dwc2_uframe_schedule_ls - Schedule a QH for a periodic low/full speed xfer.
1004  *
1005  * Basically this just wraps dwc2_ls_pmap_schedule() to provide a clean
1006  * interface.
1007  *
1008  * @hsotg:       The HCD state structure for the DWC OTG controller.
1009  * @qh:          QH for the periodic transfer.
1010  */
1011 static int dwc2_uframe_schedule_ls(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh)
1012 {
1013 	/* In non-split host and device time are the same */
1014 	WARN_ON(qh->host_us != qh->device_us);
1015 	WARN_ON(qh->host_interval != qh->device_interval);
1016 	WARN_ON(!qh->schedule_low_speed);
1017 
1018 	/* Run on the main low speed schedule (no split = no hub = no TT) */
1019 	return dwc2_ls_pmap_schedule(hsotg, qh, 0);
1020 }
1021 
1022 /**
1023  * dwc2_uframe_schedule - Schedule a QH for a periodic xfer.
1024  *
1025  * Calls one of the 3 sub-function depending on what type of transfer this QH
1026  * is for.  Also adds some printing.
1027  *
1028  * @hsotg:       The HCD state structure for the DWC OTG controller.
1029  * @qh:          QH for the periodic transfer.
1030  */
1031 static int dwc2_uframe_schedule(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh)
1032 {
1033 	int ret;
1034 
1035 	if (qh->dev_speed == USB_SPEED_HIGH)
1036 		ret = dwc2_uframe_schedule_hs(hsotg, qh);
1037 	else if (!qh->do_split)
1038 		ret = dwc2_uframe_schedule_ls(hsotg, qh);
1039 	else
1040 		ret = dwc2_uframe_schedule_split(hsotg, qh);
1041 
1042 	if (ret)
1043 		dwc2_sch_dbg(hsotg, "QH=%p Failed to schedule %d\n", qh, ret);
1044 	else
1045 		dwc2_qh_schedule_print(hsotg, qh);
1046 
1047 	return ret;
1048 }
1049 
1050 /**
1051  * dwc2_uframe_unschedule - Undoes dwc2_uframe_schedule().
1052  *
1053  * @hsotg:       The HCD state structure for the DWC OTG controller.
1054  * @qh:          QH for the periodic transfer.
1055  */
1056 static void dwc2_uframe_unschedule(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh)
1057 {
1058 	int i;
1059 
1060 	for (i = 0; i < qh->num_hs_transfers; i++)
1061 		dwc2_hs_pmap_unschedule(hsotg, qh, i);
1062 
1063 	if (qh->schedule_low_speed)
1064 		dwc2_ls_pmap_unschedule(hsotg, qh);
1065 
1066 	dwc2_sch_dbg(hsotg, "QH=%p Unscheduled\n", qh);
1067 }
1068 
1069 /**
1070  * dwc2_pick_first_frame() - Choose 1st frame for qh that's already scheduled
1071  *
1072  * Takes a qh that has already been scheduled (which means we know we have the
1073  * bandwdith reserved for us) and set the next_active_frame and the
1074  * start_active_frame.
1075  *
1076  * This is expected to be called on qh's that weren't previously actively
1077  * running.  It just picks the next frame that we can fit into without any
1078  * thought about the past.
1079  *
1080  * @hsotg: The HCD state structure for the DWC OTG controller
1081  * @qh:    QH for a periodic endpoint
1082  *
1083  */
1084 static void dwc2_pick_first_frame(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh)
1085 {
1086 	u16 frame_number;
1087 	u16 earliest_frame;
1088 	u16 next_active_frame;
1089 	u16 relative_frame;
1090 	u16 interval;
1091 
1092 	/*
1093 	 * Use the real frame number rather than the cached value as of the
1094 	 * last SOF to give us a little extra slop.
1095 	 */
1096 	frame_number = dwc2_hcd_get_frame_number(hsotg);
1097 
1098 	/*
1099 	 * We wouldn't want to start any earlier than the next frame just in
1100 	 * case the frame number ticks as we're doing this calculation.
1101 	 *
1102 	 * NOTE: if we could quantify how long till we actually get scheduled
1103 	 * we might be able to avoid the "+ 1" by looking at the upper part of
1104 	 * HFNUM (the FRREM field).  For now we'll just use the + 1 though.
1105 	 */
1106 	earliest_frame = dwc2_frame_num_inc(frame_number, 1);
1107 	next_active_frame = earliest_frame;
1108 
1109 	/* Get the "no microframe schduler" out of the way... */
1110 	if (hsotg->params.uframe_sched <= 0) {
1111 		if (qh->do_split)
1112 			/* Splits are active at microframe 0 minus 1 */
1113 			next_active_frame |= 0x7;
1114 		goto exit;
1115 	}
1116 
1117 	if (qh->dev_speed == USB_SPEED_HIGH || qh->do_split) {
1118 		/*
1119 		 * We're either at high speed or we're doing a split (which
1120 		 * means we're talking high speed to a hub).  In any case
1121 		 * the first frame should be based on when the first scheduled
1122 		 * event is.
1123 		 */
1124 		WARN_ON(qh->num_hs_transfers < 1);
1125 
1126 		relative_frame = qh->hs_transfers[0].start_schedule_us /
1127 				 DWC2_HS_PERIODIC_US_PER_UFRAME;
1128 
1129 		/* Adjust interval as per high speed schedule */
1130 		interval = gcd(qh->host_interval, DWC2_HS_SCHEDULE_UFRAMES);
1131 
1132 	} else {
1133 		/*
1134 		 * Low or full speed directly on dwc2.  Just about the same
1135 		 * as high speed but on a different schedule and with slightly
1136 		 * different adjustments.  Note that this works because when
1137 		 * the host and device are both low speed then frames in the
1138 		 * controller tick at low speed.
1139 		 */
1140 		relative_frame = qh->ls_start_schedule_slice /
1141 				 DWC2_LS_PERIODIC_SLICES_PER_FRAME;
1142 		interval = gcd(qh->host_interval, DWC2_LS_SCHEDULE_FRAMES);
1143 	}
1144 
1145 	/* Scheduler messed up if frame is past interval */
1146 	WARN_ON(relative_frame >= interval);
1147 
1148 	/*
1149 	 * We know interval must divide (HFNUM_MAX_FRNUM + 1) now that we've
1150 	 * done the gcd(), so it's safe to move to the beginning of the current
1151 	 * interval like this.
1152 	 *
1153 	 * After this we might be before earliest_frame, but don't worry,
1154 	 * we'll fix it...
1155 	 */
1156 	next_active_frame = (next_active_frame / interval) * interval;
1157 
1158 	/*
1159 	 * Actually choose to start at the frame number we've been
1160 	 * scheduled for.
1161 	 */
1162 	next_active_frame = dwc2_frame_num_inc(next_active_frame,
1163 					       relative_frame);
1164 
1165 	/*
1166 	 * We actually need 1 frame before since the next_active_frame is
1167 	 * the frame number we'll be put on the ready list and we won't be on
1168 	 * the bus until 1 frame later.
1169 	 */
1170 	next_active_frame = dwc2_frame_num_dec(next_active_frame, 1);
1171 
1172 	/*
1173 	 * By now we might actually be before the earliest_frame.  Let's move
1174 	 * up intervals until we're not.
1175 	 */
1176 	while (dwc2_frame_num_gt(earliest_frame, next_active_frame))
1177 		next_active_frame = dwc2_frame_num_inc(next_active_frame,
1178 						       interval);
1179 
1180 exit:
1181 	qh->next_active_frame = next_active_frame;
1182 	qh->start_active_frame = next_active_frame;
1183 
1184 	dwc2_sch_vdbg(hsotg, "QH=%p First fn=%04x nxt=%04x\n",
1185 		     qh, frame_number, qh->next_active_frame);
1186 }
1187 
1188 /**
1189  * dwc2_do_reserve() - Make a periodic reservation
1190  *
1191  * Try to allocate space in the periodic schedule.  Depending on parameters
1192  * this might use the microframe scheduler or the dumb scheduler.
1193  *
1194  * @hsotg: The HCD state structure for the DWC OTG controller
1195  * @qh:    QH for the periodic transfer.
1196  *
1197  * Returns: 0 upon success; error upon failure.
1198  */
1199 static int dwc2_do_reserve(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh)
1200 {
1201 	int status;
1202 
1203 	if (hsotg->params.uframe_sched > 0) {
1204 		status = dwc2_uframe_schedule(hsotg, qh);
1205 	} else {
1206 		status = dwc2_periodic_channel_available(hsotg);
1207 		if (status) {
1208 			dev_info(hsotg->dev,
1209 				 "%s: No host channel available for periodic transfer\n",
1210 				 __func__);
1211 			return status;
1212 		}
1213 
1214 		status = dwc2_check_periodic_bandwidth(hsotg, qh);
1215 	}
1216 
1217 	if (status) {
1218 		dev_dbg(hsotg->dev,
1219 			"%s: Insufficient periodic bandwidth for periodic transfer\n",
1220 			__func__);
1221 		return status;
1222 	}
1223 
1224 	if (hsotg->params.uframe_sched <= 0)
1225 		/* Reserve periodic channel */
1226 		hsotg->periodic_channels++;
1227 
1228 	/* Update claimed usecs per (micro)frame */
1229 	hsotg->periodic_usecs += qh->host_us;
1230 
1231 	dwc2_pick_first_frame(hsotg, qh);
1232 
1233 	return 0;
1234 }
1235 
1236 /**
1237  * dwc2_do_unreserve() - Actually release the periodic reservation
1238  *
1239  * This function actually releases the periodic bandwidth that was reserved
1240  * by the given qh.
1241  *
1242  * @hsotg: The HCD state structure for the DWC OTG controller
1243  * @qh:    QH for the periodic transfer.
1244  */
1245 static void dwc2_do_unreserve(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh)
1246 {
1247 	assert_spin_locked(&hsotg->lock);
1248 
1249 	WARN_ON(!qh->unreserve_pending);
1250 
1251 	/* No more unreserve pending--we're doing it */
1252 	qh->unreserve_pending = false;
1253 
1254 	if (WARN_ON(!list_empty(&qh->qh_list_entry)))
1255 		list_del_init(&qh->qh_list_entry);
1256 
1257 	/* Update claimed usecs per (micro)frame */
1258 	hsotg->periodic_usecs -= qh->host_us;
1259 
1260 	if (hsotg->params.uframe_sched > 0) {
1261 		dwc2_uframe_unschedule(hsotg, qh);
1262 	} else {
1263 		/* Release periodic channel reservation */
1264 		hsotg->periodic_channels--;
1265 	}
1266 }
1267 
1268 /**
1269  * dwc2_unreserve_timer_fn() - Timer function to release periodic reservation
1270  *
1271  * According to the kernel doc for usb_submit_urb() (specifically the part about
1272  * "Reserved Bandwidth Transfers"), we need to keep a reservation active as
1273  * long as a device driver keeps submitting.  Since we're using HCD_BH to give
1274  * back the URB we need to give the driver a little bit of time before we
1275  * release the reservation.  This worker is called after the appropriate
1276  * delay.
1277  *
1278  * @work: Pointer to a qh unreserve_work.
1279  */
1280 static void dwc2_unreserve_timer_fn(unsigned long data)
1281 {
1282 	struct dwc2_qh *qh = (struct dwc2_qh *)data;
1283 	struct dwc2_hsotg *hsotg = qh->hsotg;
1284 	unsigned long flags;
1285 
1286 	/*
1287 	 * Wait for the lock, or for us to be scheduled again.  We
1288 	 * could be scheduled again if:
1289 	 * - We started executing but didn't get the lock yet.
1290 	 * - A new reservation came in, but cancel didn't take effect
1291 	 *   because we already started executing.
1292 	 * - The timer has been kicked again.
1293 	 * In that case cancel and wait for the next call.
1294 	 */
1295 	while (!spin_trylock_irqsave(&hsotg->lock, flags)) {
1296 		if (timer_pending(&qh->unreserve_timer))
1297 			return;
1298 	}
1299 
1300 	/*
1301 	 * Might be no more unreserve pending if:
1302 	 * - We started executing but didn't get the lock yet.
1303 	 * - A new reservation came in, but cancel didn't take effect
1304 	 *   because we already started executing.
1305 	 *
1306 	 * We can't put this in the loop above because unreserve_pending needs
1307 	 * to be accessed under lock, so we can only check it once we got the
1308 	 * lock.
1309 	 */
1310 	if (qh->unreserve_pending)
1311 		dwc2_do_unreserve(hsotg, qh);
1312 
1313 	spin_unlock_irqrestore(&hsotg->lock, flags);
1314 }
1315 
1316 /**
1317  * dwc2_check_max_xfer_size() - Checks that the max transfer size allowed in a
1318  * host channel is large enough to handle the maximum data transfer in a single
1319  * (micro)frame for a periodic transfer
1320  *
1321  * @hsotg: The HCD state structure for the DWC OTG controller
1322  * @qh:    QH for a periodic endpoint
1323  *
1324  * Return: 0 if successful, negative error code otherwise
1325  */
1326 static int dwc2_check_max_xfer_size(struct dwc2_hsotg *hsotg,
1327 				    struct dwc2_qh *qh)
1328 {
1329 	u32 max_xfer_size;
1330 	u32 max_channel_xfer_size;
1331 	int status = 0;
1332 
1333 	max_xfer_size = dwc2_max_packet(qh->maxp) * dwc2_hb_mult(qh->maxp);
1334 	max_channel_xfer_size = hsotg->params.max_transfer_size;
1335 
1336 	if (max_xfer_size > max_channel_xfer_size) {
1337 		dev_err(hsotg->dev,
1338 			"%s: Periodic xfer length %d > max xfer length for channel %d\n",
1339 			__func__, max_xfer_size, max_channel_xfer_size);
1340 		status = -ENOSPC;
1341 	}
1342 
1343 	return status;
1344 }
1345 
1346 /**
1347  * dwc2_schedule_periodic() - Schedules an interrupt or isochronous transfer in
1348  * the periodic schedule
1349  *
1350  * @hsotg: The HCD state structure for the DWC OTG controller
1351  * @qh:    QH for the periodic transfer. The QH should already contain the
1352  *         scheduling information.
1353  *
1354  * Return: 0 if successful, negative error code otherwise
1355  */
1356 static int dwc2_schedule_periodic(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh)
1357 {
1358 	int status;
1359 
1360 	status = dwc2_check_max_xfer_size(hsotg, qh);
1361 	if (status) {
1362 		dev_dbg(hsotg->dev,
1363 			"%s: Channel max transfer size too small for periodic transfer\n",
1364 			__func__);
1365 		return status;
1366 	}
1367 
1368 	/* Cancel pending unreserve; if canceled OK, unreserve was pending */
1369 	if (del_timer(&qh->unreserve_timer))
1370 		WARN_ON(!qh->unreserve_pending);
1371 
1372 	/*
1373 	 * Only need to reserve if there's not an unreserve pending, since if an
1374 	 * unreserve is pending then by definition our old reservation is still
1375 	 * valid.  Unreserve might still be pending even if we didn't cancel if
1376 	 * dwc2_unreserve_timer_fn() already started.  Code in the timer handles
1377 	 * that case.
1378 	 */
1379 	if (!qh->unreserve_pending) {
1380 		status = dwc2_do_reserve(hsotg, qh);
1381 		if (status)
1382 			return status;
1383 	} else {
1384 		/*
1385 		 * It might have been a while, so make sure that frame_number
1386 		 * is still good.  Note: we could also try to use the similar
1387 		 * dwc2_next_periodic_start() but that schedules much more
1388 		 * tightly and we might need to hurry and queue things up.
1389 		 */
1390 		if (dwc2_frame_num_le(qh->next_active_frame,
1391 				      hsotg->frame_number))
1392 			dwc2_pick_first_frame(hsotg, qh);
1393 	}
1394 
1395 	qh->unreserve_pending = 0;
1396 
1397 	if (hsotg->params.dma_desc_enable > 0)
1398 		/* Don't rely on SOF and start in ready schedule */
1399 		list_add_tail(&qh->qh_list_entry, &hsotg->periodic_sched_ready);
1400 	else
1401 		/* Always start in inactive schedule */
1402 		list_add_tail(&qh->qh_list_entry,
1403 			      &hsotg->periodic_sched_inactive);
1404 
1405 	return 0;
1406 }
1407 
1408 /**
1409  * dwc2_deschedule_periodic() - Removes an interrupt or isochronous transfer
1410  * from the periodic schedule
1411  *
1412  * @hsotg: The HCD state structure for the DWC OTG controller
1413  * @qh:	   QH for the periodic transfer
1414  */
1415 static void dwc2_deschedule_periodic(struct dwc2_hsotg *hsotg,
1416 				     struct dwc2_qh *qh)
1417 {
1418 	bool did_modify;
1419 
1420 	assert_spin_locked(&hsotg->lock);
1421 
1422 	/*
1423 	 * Schedule the unreserve to happen in a little bit.  Cases here:
1424 	 * - Unreserve worker might be sitting there waiting to grab the lock.
1425 	 *   In this case it will notice it's been schedule again and will
1426 	 *   quit.
1427 	 * - Unreserve worker might not be scheduled.
1428 	 *
1429 	 * We should never already be scheduled since dwc2_schedule_periodic()
1430 	 * should have canceled the scheduled unreserve timer (hence the
1431 	 * warning on did_modify).
1432 	 *
1433 	 * We add + 1 to the timer to guarantee that at least 1 jiffy has
1434 	 * passed (otherwise if the jiffy counter might tick right after we
1435 	 * read it and we'll get no delay).
1436 	 */
1437 	did_modify = mod_timer(&qh->unreserve_timer,
1438 			       jiffies + DWC2_UNRESERVE_DELAY + 1);
1439 	WARN_ON(did_modify);
1440 	qh->unreserve_pending = 1;
1441 
1442 	list_del_init(&qh->qh_list_entry);
1443 }
1444 
1445 /**
1446  * dwc2_qh_init() - Initializes a QH structure
1447  *
1448  * @hsotg: The HCD state structure for the DWC OTG controller
1449  * @qh:    The QH to init
1450  * @urb:   Holds the information about the device/endpoint needed to initialize
1451  *         the QH
1452  * @mem_flags: Flags for allocating memory.
1453  */
1454 static void dwc2_qh_init(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh,
1455 			 struct dwc2_hcd_urb *urb, gfp_t mem_flags)
1456 {
1457 	int dev_speed = dwc2_host_get_speed(hsotg, urb->priv);
1458 	u8 ep_type = dwc2_hcd_get_pipe_type(&urb->pipe_info);
1459 	bool ep_is_in = !!dwc2_hcd_is_pipe_in(&urb->pipe_info);
1460 	bool ep_is_isoc = (ep_type == USB_ENDPOINT_XFER_ISOC);
1461 	bool ep_is_int = (ep_type == USB_ENDPOINT_XFER_INT);
1462 	u32 hprt = dwc2_readl(hsotg->regs + HPRT0);
1463 	u32 prtspd = (hprt & HPRT0_SPD_MASK) >> HPRT0_SPD_SHIFT;
1464 	bool do_split = (prtspd == HPRT0_SPD_HIGH_SPEED &&
1465 			 dev_speed != USB_SPEED_HIGH);
1466 	int maxp = dwc2_hcd_get_mps(&urb->pipe_info);
1467 	int bytecount = dwc2_hb_mult(maxp) * dwc2_max_packet(maxp);
1468 	char *speed, *type;
1469 
1470 	/* Initialize QH */
1471 	qh->hsotg = hsotg;
1472 	setup_timer(&qh->unreserve_timer, dwc2_unreserve_timer_fn,
1473 		    (unsigned long)qh);
1474 	qh->ep_type = ep_type;
1475 	qh->ep_is_in = ep_is_in;
1476 
1477 	qh->data_toggle = DWC2_HC_PID_DATA0;
1478 	qh->maxp = maxp;
1479 	INIT_LIST_HEAD(&qh->qtd_list);
1480 	INIT_LIST_HEAD(&qh->qh_list_entry);
1481 
1482 	qh->do_split = do_split;
1483 	qh->dev_speed = dev_speed;
1484 
1485 	if (ep_is_int || ep_is_isoc) {
1486 		/* Compute scheduling parameters once and save them */
1487 		int host_speed = do_split ? USB_SPEED_HIGH : dev_speed;
1488 		struct dwc2_tt *dwc_tt = dwc2_host_get_tt_info(hsotg, urb->priv,
1489 							       mem_flags,
1490 							       &qh->ttport);
1491 		int device_ns;
1492 
1493 		qh->dwc_tt = dwc_tt;
1494 
1495 		qh->host_us = NS_TO_US(usb_calc_bus_time(host_speed, ep_is_in,
1496 				       ep_is_isoc, bytecount));
1497 		device_ns = usb_calc_bus_time(dev_speed, ep_is_in,
1498 					      ep_is_isoc, bytecount);
1499 
1500 		if (do_split && dwc_tt)
1501 			device_ns += dwc_tt->usb_tt->think_time;
1502 		qh->device_us = NS_TO_US(device_ns);
1503 
1504 
1505 		qh->device_interval = urb->interval;
1506 		qh->host_interval = urb->interval * (do_split ? 8 : 1);
1507 
1508 		/*
1509 		 * Schedule low speed if we're running the host in low or
1510 		 * full speed OR if we've got a "TT" to deal with to access this
1511 		 * device.
1512 		 */
1513 		qh->schedule_low_speed = prtspd != HPRT0_SPD_HIGH_SPEED ||
1514 					 dwc_tt;
1515 
1516 		if (do_split) {
1517 			/* We won't know num transfers until we schedule */
1518 			qh->num_hs_transfers = -1;
1519 		} else if (dev_speed == USB_SPEED_HIGH) {
1520 			qh->num_hs_transfers = 1;
1521 		} else {
1522 			qh->num_hs_transfers = 0;
1523 		}
1524 
1525 		/* We'll schedule later when we have something to do */
1526 	}
1527 
1528 	switch (dev_speed) {
1529 	case USB_SPEED_LOW:
1530 		speed = "low";
1531 		break;
1532 	case USB_SPEED_FULL:
1533 		speed = "full";
1534 		break;
1535 	case USB_SPEED_HIGH:
1536 		speed = "high";
1537 		break;
1538 	default:
1539 		speed = "?";
1540 		break;
1541 	}
1542 
1543 	switch (qh->ep_type) {
1544 	case USB_ENDPOINT_XFER_ISOC:
1545 		type = "isochronous";
1546 		break;
1547 	case USB_ENDPOINT_XFER_INT:
1548 		type = "interrupt";
1549 		break;
1550 	case USB_ENDPOINT_XFER_CONTROL:
1551 		type = "control";
1552 		break;
1553 	case USB_ENDPOINT_XFER_BULK:
1554 		type = "bulk";
1555 		break;
1556 	default:
1557 		type = "?";
1558 		break;
1559 	}
1560 
1561 	dwc2_sch_dbg(hsotg, "QH=%p Init %s, %s speed, %d bytes:\n", qh, type,
1562 		     speed, bytecount);
1563 	dwc2_sch_dbg(hsotg, "QH=%p ...addr=%d, ep=%d, %s\n", qh,
1564 		     dwc2_hcd_get_dev_addr(&urb->pipe_info),
1565 		     dwc2_hcd_get_ep_num(&urb->pipe_info),
1566 		     ep_is_in ? "IN" : "OUT");
1567 	if (ep_is_int || ep_is_isoc) {
1568 		dwc2_sch_dbg(hsotg,
1569 			     "QH=%p ...duration: host=%d us, device=%d us\n",
1570 			     qh, qh->host_us, qh->device_us);
1571 		dwc2_sch_dbg(hsotg, "QH=%p ...interval: host=%d, device=%d\n",
1572 			     qh, qh->host_interval, qh->device_interval);
1573 		if (qh->schedule_low_speed)
1574 			dwc2_sch_dbg(hsotg, "QH=%p ...low speed schedule=%p\n",
1575 				     qh, dwc2_get_ls_map(hsotg, qh));
1576 	}
1577 }
1578 
1579 /**
1580  * dwc2_hcd_qh_create() - Allocates and initializes a QH
1581  *
1582  * @hsotg:        The HCD state structure for the DWC OTG controller
1583  * @urb:          Holds the information about the device/endpoint needed
1584  *                to initialize the QH
1585  * @atomic_alloc: Flag to do atomic allocation if needed
1586  *
1587  * Return: Pointer to the newly allocated QH, or NULL on error
1588  */
1589 struct dwc2_qh *dwc2_hcd_qh_create(struct dwc2_hsotg *hsotg,
1590 					  struct dwc2_hcd_urb *urb,
1591 					  gfp_t mem_flags)
1592 {
1593 	struct dwc2_qh *qh;
1594 
1595 	if (!urb->priv)
1596 		return NULL;
1597 
1598 	/* Allocate memory */
1599 	qh = kzalloc(sizeof(*qh), mem_flags);
1600 	if (!qh)
1601 		return NULL;
1602 
1603 	dwc2_qh_init(hsotg, qh, urb, mem_flags);
1604 
1605 	if (hsotg->params.dma_desc_enable > 0 &&
1606 	    dwc2_hcd_qh_init_ddma(hsotg, qh, mem_flags) < 0) {
1607 		dwc2_hcd_qh_free(hsotg, qh);
1608 		return NULL;
1609 	}
1610 
1611 	return qh;
1612 }
1613 
1614 /**
1615  * dwc2_hcd_qh_free() - Frees the QH
1616  *
1617  * @hsotg: HCD instance
1618  * @qh:    The QH to free
1619  *
1620  * QH should already be removed from the list. QTD list should already be empty
1621  * if called from URB Dequeue.
1622  *
1623  * Must NOT be called with interrupt disabled or spinlock held
1624  */
1625 void dwc2_hcd_qh_free(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh)
1626 {
1627 	/* Make sure any unreserve work is finished. */
1628 	if (del_timer_sync(&qh->unreserve_timer)) {
1629 		unsigned long flags;
1630 
1631 		spin_lock_irqsave(&hsotg->lock, flags);
1632 		dwc2_do_unreserve(hsotg, qh);
1633 		spin_unlock_irqrestore(&hsotg->lock, flags);
1634 	}
1635 	dwc2_host_put_tt_info(hsotg, qh->dwc_tt);
1636 
1637 	if (qh->desc_list)
1638 		dwc2_hcd_qh_free_ddma(hsotg, qh);
1639 	kfree(qh);
1640 }
1641 
1642 /**
1643  * dwc2_hcd_qh_add() - Adds a QH to either the non periodic or periodic
1644  * schedule if it is not already in the schedule. If the QH is already in
1645  * the schedule, no action is taken.
1646  *
1647  * @hsotg: The HCD state structure for the DWC OTG controller
1648  * @qh:    The QH to add
1649  *
1650  * Return: 0 if successful, negative error code otherwise
1651  */
1652 int dwc2_hcd_qh_add(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh)
1653 {
1654 	int status;
1655 	u32 intr_mask;
1656 
1657 	if (dbg_qh(qh))
1658 		dev_vdbg(hsotg->dev, "%s()\n", __func__);
1659 
1660 	if (!list_empty(&qh->qh_list_entry))
1661 		/* QH already in a schedule */
1662 		return 0;
1663 
1664 	/* Add the new QH to the appropriate schedule */
1665 	if (dwc2_qh_is_non_per(qh)) {
1666 		/* Schedule right away */
1667 		qh->start_active_frame = hsotg->frame_number;
1668 		qh->next_active_frame = qh->start_active_frame;
1669 
1670 		/* Always start in inactive schedule */
1671 		list_add_tail(&qh->qh_list_entry,
1672 			      &hsotg->non_periodic_sched_inactive);
1673 		return 0;
1674 	}
1675 
1676 	status = dwc2_schedule_periodic(hsotg, qh);
1677 	if (status)
1678 		return status;
1679 	if (!hsotg->periodic_qh_count) {
1680 		intr_mask = dwc2_readl(hsotg->regs + GINTMSK);
1681 		intr_mask |= GINTSTS_SOF;
1682 		dwc2_writel(intr_mask, hsotg->regs + GINTMSK);
1683 	}
1684 	hsotg->periodic_qh_count++;
1685 
1686 	return 0;
1687 }
1688 
1689 /**
1690  * dwc2_hcd_qh_unlink() - Removes a QH from either the non-periodic or periodic
1691  * schedule. Memory is not freed.
1692  *
1693  * @hsotg: The HCD state structure
1694  * @qh:    QH to remove from schedule
1695  */
1696 void dwc2_hcd_qh_unlink(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh)
1697 {
1698 	u32 intr_mask;
1699 
1700 	dev_vdbg(hsotg->dev, "%s()\n", __func__);
1701 
1702 	if (list_empty(&qh->qh_list_entry))
1703 		/* QH is not in a schedule */
1704 		return;
1705 
1706 	if (dwc2_qh_is_non_per(qh)) {
1707 		if (hsotg->non_periodic_qh_ptr == &qh->qh_list_entry)
1708 			hsotg->non_periodic_qh_ptr =
1709 					hsotg->non_periodic_qh_ptr->next;
1710 		list_del_init(&qh->qh_list_entry);
1711 		return;
1712 	}
1713 
1714 	dwc2_deschedule_periodic(hsotg, qh);
1715 	hsotg->periodic_qh_count--;
1716 	if (!hsotg->periodic_qh_count &&
1717 	    hsotg->params.dma_desc_enable <= 0) {
1718 		intr_mask = dwc2_readl(hsotg->regs + GINTMSK);
1719 		intr_mask &= ~GINTSTS_SOF;
1720 		dwc2_writel(intr_mask, hsotg->regs + GINTMSK);
1721 	}
1722 }
1723 
1724 /**
1725  * dwc2_next_for_periodic_split() - Set next_active_frame midway thru a split.
1726  *
1727  * This is called for setting next_active_frame for periodic splits for all but
1728  * the first packet of the split.  Confusing?  I thought so...
1729  *
1730  * Periodic splits are single low/full speed transfers that we end up splitting
1731  * up into several high speed transfers.  They always fit into one full (1 ms)
1732  * frame but might be split over several microframes (125 us each).  We to put
1733  * each of the parts on a very specific high speed frame.
1734  *
1735  * This function figures out where the next active uFrame needs to be.
1736  *
1737  * @hsotg:        The HCD state structure
1738  * @qh:           QH for the periodic transfer.
1739  * @frame_number: The current frame number.
1740  *
1741  * Return: number missed by (or 0 if we didn't miss).
1742  */
1743 static int dwc2_next_for_periodic_split(struct dwc2_hsotg *hsotg,
1744 					 struct dwc2_qh *qh, u16 frame_number)
1745 {
1746 	u16 old_frame = qh->next_active_frame;
1747 	u16 prev_frame_number = dwc2_frame_num_dec(frame_number, 1);
1748 	int missed = 0;
1749 	u16 incr;
1750 
1751 	/*
1752 	 * See dwc2_uframe_schedule_split() for split scheduling.
1753 	 *
1754 	 * Basically: increment 1 normally, but 2 right after the start split
1755 	 * (except for ISOC out).
1756 	 */
1757 	if (old_frame == qh->start_active_frame &&
1758 	    !(qh->ep_type == USB_ENDPOINT_XFER_ISOC && !qh->ep_is_in))
1759 		incr = 2;
1760 	else
1761 		incr = 1;
1762 
1763 	qh->next_active_frame = dwc2_frame_num_inc(old_frame, incr);
1764 
1765 	/*
1766 	 * Note that it's OK for frame_number to be 1 frame past
1767 	 * next_active_frame.  Remember that next_active_frame is supposed to
1768 	 * be 1 frame _before_ when we want to be scheduled.  If we're 1 frame
1769 	 * past it just means schedule ASAP.
1770 	 *
1771 	 * It's _not_ OK, however, if we're more than one frame past.
1772 	 */
1773 	if (dwc2_frame_num_gt(prev_frame_number, qh->next_active_frame)) {
1774 		/*
1775 		 * OOPS, we missed.  That's actually pretty bad since
1776 		 * the hub will be unhappy; try ASAP I guess.
1777 		 */
1778 		missed = dwc2_frame_num_dec(prev_frame_number,
1779 					    qh->next_active_frame);
1780 		qh->next_active_frame = frame_number;
1781 	}
1782 
1783 	return missed;
1784 }
1785 
1786 /**
1787  * dwc2_next_periodic_start() - Set next_active_frame for next transfer start
1788  *
1789  * This is called for setting next_active_frame for a periodic transfer for
1790  * all cases other than midway through a periodic split.  This will also update
1791  * start_active_frame.
1792  *
1793  * Since we _always_ keep start_active_frame as the start of the previous
1794  * transfer this is normally pretty easy: we just add our interval to
1795  * start_active_frame and we've got our answer.
1796  *
1797  * The tricks come into play if we miss.  In that case we'll look for the next
1798  * slot we can fit into.
1799  *
1800  * @hsotg:        The HCD state structure
1801  * @qh:           QH for the periodic transfer.
1802  * @frame_number: The current frame number.
1803  *
1804  * Return: number missed by (or 0 if we didn't miss).
1805  */
1806 static int dwc2_next_periodic_start(struct dwc2_hsotg *hsotg,
1807 				     struct dwc2_qh *qh, u16 frame_number)
1808 {
1809 	int missed = 0;
1810 	u16 interval = qh->host_interval;
1811 	u16 prev_frame_number = dwc2_frame_num_dec(frame_number, 1);
1812 
1813 	qh->start_active_frame = dwc2_frame_num_inc(qh->start_active_frame,
1814 						    interval);
1815 
1816 	/*
1817 	 * The dwc2_frame_num_gt() function used below won't work terribly well
1818 	 * with if we just incremented by a really large intervals since the
1819 	 * frame counter only goes to 0x3fff.  It's terribly unlikely that we
1820 	 * will have missed in this case anyway.  Just go to exit.  If we want
1821 	 * to try to do better we'll need to keep track of a bigger counter
1822 	 * somewhere in the driver and handle overflows.
1823 	 */
1824 	if (interval >= 0x1000)
1825 		goto exit;
1826 
1827 	/*
1828 	 * Test for misses, which is when it's too late to schedule.
1829 	 *
1830 	 * A few things to note:
1831 	 * - We compare against prev_frame_number since start_active_frame
1832 	 *   and next_active_frame are always 1 frame before we want things
1833 	 *   to be active and we assume we can still get scheduled in the
1834 	 *   current frame number.
1835 	 * - It's possible for start_active_frame (now incremented) to be
1836 	 *   next_active_frame if we got an EO MISS (even_odd miss) which
1837 	 *   basically means that we detected there wasn't enough time for
1838 	 *   the last packet and dwc2_hc_set_even_odd_frame() rescheduled us
1839 	 *   at the last second.  We want to make sure we don't schedule
1840 	 *   another transfer for the same frame.  My test webcam doesn't seem
1841 	 *   terribly upset by missing a transfer but really doesn't like when
1842 	 *   we do two transfers in the same frame.
1843 	 * - Some misses are expected.  Specifically, in order to work
1844 	 *   perfectly dwc2 really needs quite spectacular interrupt latency
1845 	 *   requirements.  It needs to be able to handle its interrupts
1846 	 *   completely within 125 us of them being asserted. That not only
1847 	 *   means that the dwc2 interrupt handler needs to be fast but it
1848 	 *   means that nothing else in the system has to block dwc2 for a long
1849 	 *   time.  We can help with the dwc2 parts of this, but it's hard to
1850 	 *   guarantee that a system will have interrupt latency < 125 us, so
1851 	 *   we have to be robust to some misses.
1852 	 */
1853 	if (qh->start_active_frame == qh->next_active_frame ||
1854 	    dwc2_frame_num_gt(prev_frame_number, qh->start_active_frame)) {
1855 		u16 ideal_start = qh->start_active_frame;
1856 		int periods_in_map;
1857 
1858 		/*
1859 		 * Adjust interval as per gcd with map size.
1860 		 * See pmap_schedule() for more details here.
1861 		 */
1862 		if (qh->do_split || qh->dev_speed == USB_SPEED_HIGH)
1863 			periods_in_map = DWC2_HS_SCHEDULE_UFRAMES;
1864 		else
1865 			periods_in_map = DWC2_LS_SCHEDULE_FRAMES;
1866 		interval = gcd(interval, periods_in_map);
1867 
1868 		do {
1869 			qh->start_active_frame = dwc2_frame_num_inc(
1870 				qh->start_active_frame, interval);
1871 		} while (dwc2_frame_num_gt(prev_frame_number,
1872 					   qh->start_active_frame));
1873 
1874 		missed = dwc2_frame_num_dec(qh->start_active_frame,
1875 					    ideal_start);
1876 	}
1877 
1878 exit:
1879 	qh->next_active_frame = qh->start_active_frame;
1880 
1881 	return missed;
1882 }
1883 
1884 /*
1885  * Deactivates a QH. For non-periodic QHs, removes the QH from the active
1886  * non-periodic schedule. The QH is added to the inactive non-periodic
1887  * schedule if any QTDs are still attached to the QH.
1888  *
1889  * For periodic QHs, the QH is removed from the periodic queued schedule. If
1890  * there are any QTDs still attached to the QH, the QH is added to either the
1891  * periodic inactive schedule or the periodic ready schedule and its next
1892  * scheduled frame is calculated. The QH is placed in the ready schedule if
1893  * the scheduled frame has been reached already. Otherwise it's placed in the
1894  * inactive schedule. If there are no QTDs attached to the QH, the QH is
1895  * completely removed from the periodic schedule.
1896  */
1897 void dwc2_hcd_qh_deactivate(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh,
1898 			    int sched_next_periodic_split)
1899 {
1900 	u16 old_frame = qh->next_active_frame;
1901 	u16 frame_number;
1902 	int missed;
1903 
1904 	if (dbg_qh(qh))
1905 		dev_vdbg(hsotg->dev, "%s()\n", __func__);
1906 
1907 	if (dwc2_qh_is_non_per(qh)) {
1908 		dwc2_hcd_qh_unlink(hsotg, qh);
1909 		if (!list_empty(&qh->qtd_list))
1910 			/* Add back to inactive non-periodic schedule */
1911 			dwc2_hcd_qh_add(hsotg, qh);
1912 		return;
1913 	}
1914 
1915 	/*
1916 	 * Use the real frame number rather than the cached value as of the
1917 	 * last SOF just to get us a little closer to reality.  Note that
1918 	 * means we don't actually know if we've already handled the SOF
1919 	 * interrupt for this frame.
1920 	 */
1921 	frame_number = dwc2_hcd_get_frame_number(hsotg);
1922 
1923 	if (sched_next_periodic_split)
1924 		missed = dwc2_next_for_periodic_split(hsotg, qh, frame_number);
1925 	else
1926 		missed = dwc2_next_periodic_start(hsotg, qh, frame_number);
1927 
1928 	dwc2_sch_vdbg(hsotg,
1929 		     "QH=%p next(%d) fn=%04x, sch=%04x=>%04x (%+d) miss=%d %s\n",
1930 		     qh, sched_next_periodic_split, frame_number, old_frame,
1931 		     qh->next_active_frame,
1932 		     dwc2_frame_num_dec(qh->next_active_frame, old_frame),
1933 		missed, missed ? "MISS" : "");
1934 
1935 	if (list_empty(&qh->qtd_list)) {
1936 		dwc2_hcd_qh_unlink(hsotg, qh);
1937 		return;
1938 	}
1939 
1940 	/*
1941 	 * Remove from periodic_sched_queued and move to
1942 	 * appropriate queue
1943 	 *
1944 	 * Note: we purposely use the frame_number from the "hsotg" structure
1945 	 * since we know SOF interrupt will handle future frames.
1946 	 */
1947 	if (dwc2_frame_num_le(qh->next_active_frame, hsotg->frame_number))
1948 		list_move_tail(&qh->qh_list_entry,
1949 			       &hsotg->periodic_sched_ready);
1950 	else
1951 		list_move_tail(&qh->qh_list_entry,
1952 			       &hsotg->periodic_sched_inactive);
1953 }
1954 
1955 /**
1956  * dwc2_hcd_qtd_init() - Initializes a QTD structure
1957  *
1958  * @qtd: The QTD to initialize
1959  * @urb: The associated URB
1960  */
1961 void dwc2_hcd_qtd_init(struct dwc2_qtd *qtd, struct dwc2_hcd_urb *urb)
1962 {
1963 	qtd->urb = urb;
1964 	if (dwc2_hcd_get_pipe_type(&urb->pipe_info) ==
1965 			USB_ENDPOINT_XFER_CONTROL) {
1966 		/*
1967 		 * The only time the QTD data toggle is used is on the data
1968 		 * phase of control transfers. This phase always starts with
1969 		 * DATA1.
1970 		 */
1971 		qtd->data_toggle = DWC2_HC_PID_DATA1;
1972 		qtd->control_phase = DWC2_CONTROL_SETUP;
1973 	}
1974 
1975 	/* Start split */
1976 	qtd->complete_split = 0;
1977 	qtd->isoc_split_pos = DWC2_HCSPLT_XACTPOS_ALL;
1978 	qtd->isoc_split_offset = 0;
1979 	qtd->in_process = 0;
1980 
1981 	/* Store the qtd ptr in the urb to reference the QTD */
1982 	urb->qtd = qtd;
1983 }
1984 
1985 /**
1986  * dwc2_hcd_qtd_add() - Adds a QTD to the QTD-list of a QH
1987  *			Caller must hold driver lock.
1988  *
1989  * @hsotg:        The DWC HCD structure
1990  * @qtd:          The QTD to add
1991  * @qh:           Queue head to add qtd to
1992  *
1993  * Return: 0 if successful, negative error code otherwise
1994  *
1995  * If the QH to which the QTD is added is not currently scheduled, it is placed
1996  * into the proper schedule based on its EP type.
1997  */
1998 int dwc2_hcd_qtd_add(struct dwc2_hsotg *hsotg, struct dwc2_qtd *qtd,
1999 		     struct dwc2_qh *qh)
2000 {
2001 	int retval;
2002 
2003 	if (unlikely(!qh)) {
2004 		dev_err(hsotg->dev, "%s: Invalid QH\n", __func__);
2005 		retval = -EINVAL;
2006 		goto fail;
2007 	}
2008 
2009 	retval = dwc2_hcd_qh_add(hsotg, qh);
2010 	if (retval)
2011 		goto fail;
2012 
2013 	qtd->qh = qh;
2014 	list_add_tail(&qtd->qtd_list_entry, &qh->qtd_list);
2015 
2016 	return 0;
2017 fail:
2018 	return retval;
2019 }
2020