xref: /dragonfly/sys/dev/misc/evdev/evdev_mt.c (revision a162a738eca94f99d45d88429e86cfd0fbfbe95d)
1 /*-
2  * Copyright (c) 2016, 2020 Vladimir Kondratyev <wulf@FreeBSD.org>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  *
26  * $FreeBSD$
27  */
28 /*-
29  * Copyright (c) 2015, 2016 Ulf Brosziewski
30  *
31  * Permission to use, copy, modify, and distribute this software for any
32  * purpose with or without fee is hereby granted, provided that the above
33  * copyright notice and this permission notice appear in all copies.
34  *
35  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
36  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
37  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
38  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
39  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
40  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
41  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
42  */
43 
44 #include "opt_evdev.h"
45 
46 #include <sys/param.h>
47 #include <sys/lock.h>
48 #include <sys/malloc.h>
49 #include <sys/systm.h>
50 #include <sys/limits.h>
51 
52 #include <dev/misc/evdev/evdev.h>
53 #include <dev/misc/evdev/evdev_private.h>
54 #include <dev/misc/evdev/input.h>
55 
56 #ifdef DEBUG
57 #define   debugf(fmt, args...)          kprintf("evdev: " fmt "\n", ##args)
58 #else
59 #define   debugf(fmt, args...)
60 #endif
61 
62 typedef   u_int32_t slotset_t;
63 
64 _Static_assert(MAX_MT_SLOTS < sizeof(slotset_t) * 8, "MAX_MT_SLOTS too big");
65 
66 #define FOREACHBIT(v, i) \
67           for ((i) = ffs(v) - 1; (i) != -1; (i) = ffs((v) & (~1 << (i))) - 1)
68 
69 static struct {
70           uint16_t  mt;
71           uint16_t  st;
72           int32_t             max;
73 } evdev_mtstmap[] = {
74           { ABS_MT_POSITION_X,          ABS_X,              0 },
75           { ABS_MT_POSITION_Y,          ABS_Y,              0 },
76           { ABS_MT_PRESSURE,  ABS_PRESSURE,       255 },
77           { ABS_MT_TOUCH_MAJOR,         ABS_TOOL_WIDTH,     15 },
78 };
79 
80 struct evdev_mt {
81           int                           last_reported_slot;
82           uint16_t            tracking_id;
83           int32_t                       tracking_ids[MAX_MT_SLOTS];
84           bool                          type_a;
85           u_int                         mtst_events;
86           /* the set of slots with active touches */
87           slotset_t           touches;
88           /* the set of slots with unsynchronized state */
89           slotset_t           frame;
90           /* the set of slots to match with active touches */
91           slotset_t           match_frame;
92           int                           match_slot;
93           union evdev_mt_slot *match_slots;
94           int                           *matrix;
95           union evdev_mt_slot slots[];
96 };
97 
98 static void         evdev_mt_support_st_compat(struct evdev_dev *);
99 static void         evdev_mt_send_st_compat(struct evdev_dev *);
100 static void         evdev_mt_send_autorel(struct evdev_dev *);
101 static void         evdev_mt_replay_events(struct evdev_dev *);
102 
103 static inline int
ffc_slot(struct evdev_dev * evdev,slotset_t slots)104 ffc_slot(struct evdev_dev *evdev, slotset_t slots)
105 {
106           return (ffs(~slots & ((2U << MAXIMAL_MT_SLOT(evdev)) - 1)) - 1);
107 }
108 
109 void
evdev_mt_init(struct evdev_dev * evdev)110 evdev_mt_init(struct evdev_dev *evdev)
111 {
112           struct evdev_mt *mt;
113           size_t size = offsetof(struct evdev_mt, slots);
114           int slot, slots;
115           bool type_a;
116 
117           type_a = !bit_test(evdev->ev_abs_flags, ABS_MT_SLOT);
118           if (type_a) {
119                     /* Add events produced by MT type A to type B converter */
120                     evdev_support_abs(evdev,
121                         ABS_MT_SLOT, 0, MAX_MT_SLOTS - 1, 0, 0, 0);
122                     evdev_support_abs(evdev,
123                         ABS_MT_TRACKING_ID, -1, MAX_MT_SLOTS - 1, 0, 0, 0);
124           }
125 
126           slots = MAXIMAL_MT_SLOT(evdev) + 1;
127           size += sizeof(mt->slots[0]) * slots;
128           if (bit_test(evdev->ev_flags, EVDEV_FLAG_MT_TRACK)) {
129                     size += sizeof(mt->match_slots[0]) * slots;
130                     size += sizeof(mt->matrix[0]) * (slots + 6) * slots;
131           }
132 
133           mt = kmalloc(size, M_EVDEV, M_WAITOK | M_ZERO);
134           evdev->ev_mt = mt;
135           mt->type_a = type_a;
136 
137           if (bit_test(evdev->ev_flags, EVDEV_FLAG_MT_TRACK)) {
138                     mt->match_slots = mt->slots + slots;
139                     mt->matrix = (int *)(mt->match_slots + slots);
140           }
141 
142           /* Initialize multitouch protocol type B states */
143           for (slot = 0; slot < slots; slot++)
144                     mt->slots[slot].id = -1;
145 
146           if (!bit_test(evdev->ev_flags, EVDEV_FLAG_MT_KEEPID))
147                     evdev_support_abs(evdev,
148                         ABS_MT_TRACKING_ID, -1, UINT16_MAX, 0, 0, 0);
149           if (bit_test(evdev->ev_flags, EVDEV_FLAG_MT_STCOMPAT))
150                     evdev_mt_support_st_compat(evdev);
151 }
152 
153 void
evdev_mt_free(struct evdev_dev * evdev)154 evdev_mt_free(struct evdev_dev *evdev)
155 {
156           kfree(evdev->ev_mt, M_EVDEV);
157 }
158 
159 void
evdev_mt_sync_frame(struct evdev_dev * evdev)160 evdev_mt_sync_frame(struct evdev_dev *evdev)
161 {
162           if (bit_test(evdev->ev_flags, EVDEV_FLAG_MT_TRACK))
163                     evdev_mt_replay_events(evdev);
164           if (bit_test(evdev->ev_flags, EVDEV_FLAG_MT_AUTOREL))
165                     evdev_mt_send_autorel(evdev);
166           if (evdev->ev_report_opened &&
167               bit_test(evdev->ev_flags, EVDEV_FLAG_MT_STCOMPAT))
168                     evdev_mt_send_st_compat(evdev);
169           evdev->ev_mt->frame = 0;
170 }
171 
172 static void
evdev_mt_send_slot(struct evdev_dev * evdev,int slot,union evdev_mt_slot * state)173 evdev_mt_send_slot(struct evdev_dev *evdev, int slot,
174     union evdev_mt_slot *state)
175 {
176           int i;
177           bool type_a = !bit_test(evdev->ev_abs_flags, ABS_MT_SLOT);
178 
179           EVDEV_LOCK_ASSERT(evdev);
180           KKASSERT(type_a || (slot >= 0 && slot <= MAXIMAL_MT_SLOT(evdev)));
181           KKASSERT(!type_a || state != NULL);
182 
183           if (!type_a) {
184                     evdev_send_event(evdev, EV_ABS, ABS_MT_SLOT, slot);
185                     if (state == NULL) {
186                               evdev_send_event(evdev, EV_ABS, ABS_MT_TRACKING_ID, -1);
187                               return;
188                     }
189           }
190           bit_foreach_at(evdev->ev_abs_flags, ABS_MT_FIRST, ABS_MT_LAST + 1, i)
191                     evdev_send_event(evdev, EV_ABS, i,
192                         state->val[ABS_MT_INDEX(i)]);
193           if (type_a)
194                     evdev_send_event(evdev, EV_SYN, SYN_MT_REPORT, 1);
195 }
196 
197 int
evdev_mt_push_slot(struct evdev_dev * evdev,int slot,union evdev_mt_slot * state)198 evdev_mt_push_slot(struct evdev_dev *evdev, int slot,
199     union evdev_mt_slot *state)
200 {
201           struct evdev_mt *mt = evdev->ev_mt;
202           bool type_a = !bit_test(evdev->ev_abs_flags, ABS_MT_SLOT);
203 
204           if ((type_a || (mt != NULL && mt->type_a)) && state == NULL)
205                     return (EINVAL);
206           if (!type_a && (slot < 0 || slot > MAXIMAL_MT_SLOT(evdev)))
207                     return (EINVAL);
208 
209           EVDEV_ENTER(evdev);
210           if (bit_test(evdev->ev_flags, EVDEV_FLAG_MT_TRACK) && mt->type_a) {
211                     mt->match_slots[mt->match_slot] = *state;
212                     evdev_mt_record_event(evdev, EV_SYN, SYN_MT_REPORT, 1);
213           } else if (bit_test(evdev->ev_flags, EVDEV_FLAG_MT_TRACK)) {
214                     evdev_mt_record_event(evdev, EV_ABS, ABS_MT_SLOT, slot);
215                     if (state != NULL)
216                               mt->match_slots[mt->match_slot] = *state;
217                     else
218                               evdev_mt_record_event(evdev, EV_ABS,
219                                   ABS_MT_TRACKING_ID, -1);
220           } else
221                     evdev_mt_send_slot(evdev, slot, state);
222           EVDEV_EXIT(evdev);
223 
224           return (0);
225 }
226 
227 /*
228  * Find a minimum-weight matching for an m-by-n matrix.
229  *
230  * m must be greater than or equal to n. The size of the buffer must be
231  * at least 3m + 3n.
232  *
233  * On return, the first m elements of the buffer contain the row-to-
234  * column mappings, i.e., buffer[i] is the column index for row i, or -1
235  * if there is no assignment for that row (which may happen if n < m).
236  *
237  * Wrong results because of overflows will not occur with input values
238  * in the range of 0 to INT_MAX / 2 inclusive.
239  *
240  * The function applies the Dinic-Kronrod algorithm. It is not modern or
241  * popular, but it seems to be a good choice for small matrices at least.
242  * The original form of the algorithm is modified as follows: There is no
243  * initial search for row minima, the initial assignments are in a
244  * "virtual" column with the index -1 and zero values. This permits inputs
245  * with n < m, and it simplifies the reassignments.
246  */
247 static void
evdev_mt_matching(int * matrix,int m,int n,int * buffer)248 evdev_mt_matching(int *matrix, int m, int n, int *buffer)
249 {
250           int i, j, k, d, e, row, col, delta;
251           int *p;
252           int *r2c = buffer;  /* row-to-column assignments */
253           int *red = r2c + m; /* reduced values of the assignments */
254           int *mc = red + m;  /* row-wise minimal elements of cs */
255           int *cs = mc + m;   /* the column set */
256           int *c2r = cs + n;  /* column-to-row assignments in cs */
257           int *cd = c2r + n;  /* column deltas (reduction) */
258 
259           row = 0; /* fixes maybe-uninitialized warning */
260 
261           for (p = r2c; p < red; *p++ = -1) {}
262           for (; p < mc; *p++ = 0) {}
263           for (col = 0; col < n; col++) {
264                     delta = INT_MAX;
265                     for (i = 0, p = matrix + col; i < m; i++, p += n) {
266                               d = *p - red[i];
267                               if (d < delta || (d == delta && r2c[i] < 0)) {
268                                         delta = d;
269                                         row = i;
270                               }
271                     }
272                     cd[col] = delta;
273                     if (r2c[row] < 0) {
274                               r2c[row] = col;
275                               continue;
276                     }
277                     for (p = mc; p < cs; *p++ = col) {}
278                     for (k = 0; (j = r2c[row]) >= 0;) {
279                               cs[k++] = j;
280                               c2r[j] = row;
281                               mc[row] -= n;
282                               delta = INT_MAX;
283                               for (i = 0, p = matrix; i < m; i++, p += n)
284                                         if (mc[i] >= 0) {
285                                                   d = p[mc[i]] - cd[mc[i]];
286                                                   e = p[j] - cd[j];
287                                                   if (e < d) {
288                                                             d = e;
289                                                             mc[i] = j;
290                                                   }
291                                                   d -= red[i];
292                                                   if (d < delta || (d == delta
293                                                       && r2c[i] < 0)) {
294                                                             delta = d;
295                                                             row = i;
296                                                   }
297                                         }
298                               cd[col] += delta;
299                               for (i = 0; i < k; i++) {
300                                         cd[cs[i]] += delta;
301                                         red[c2r[cs[i]]] -= delta;
302                               }
303                     }
304                     for (j = mc[row]; (r2c[row] = j) != col;) {
305                               row = c2r[j];
306                               j = mc[row] + n;
307                     }
308           }
309 }
310 
311 /*
312  * Assign tracking IDs to the points in the pt array.  The tracking ID
313  * assignment pairs the points with points of the previous frame in
314  * such a way that the sum of the squared distances is minimal.  Using
315  * squares instead of simple distances favours assignments with more uniform
316  * distances, and it is faster.
317  * Set tracking id to -1 for unassigned (new) points.
318  */
319 void
evdev_mt_match_frame(struct evdev_dev * evdev,union evdev_mt_slot * pt,int size)320 evdev_mt_match_frame(struct evdev_dev *evdev, union evdev_mt_slot *pt,
321     int size)
322 {
323           struct evdev_mt *mt = evdev->ev_mt;
324           int i, j, m, n, dx, dy, slot, num_touches;
325           int *p, *r2c, *c2r;
326 
327           EVDEV_LOCK_ASSERT(evdev);
328           KKASSERT(mt->matrix != NULL);
329           KKASSERT(size >= 0 && size <= MAXIMAL_MT_SLOT(evdev) + 1);
330 
331           if (size == 0)
332                     return;
333 
334           p = mt->matrix;
335           num_touches = bitcount32(mt->touches);
336           if (num_touches >= size) {
337                     FOREACHBIT(mt->touches, slot)
338                               for (i = 0; i < size; i++) {
339                                         dx = pt[i].x - mt->slots[slot].x;
340                                         dy = pt[i].y - mt->slots[slot].y;
341                                         *p++ = dx * dx + dy * dy;
342                               }
343                     m = num_touches;
344                     n = size;
345           } else {
346                     for (i = 0; i < size; i++)
347                               FOREACHBIT(mt->touches, slot) {
348                                         dx = pt[i].x - mt->slots[slot].x;
349                                         dy = pt[i].y - mt->slots[slot].y;
350                                         *p++ = dx * dx + dy * dy;
351                               }
352                     m = size;
353                     n = num_touches;
354           }
355           evdev_mt_matching(mt->matrix, m, n, p);
356 
357           r2c = p;
358           c2r = p + m;
359           for (i = 0; i < m; i++)
360                     if ((j = r2c[i]) >= 0)
361                               c2r[j] = i;
362 
363           p = (n == size ? c2r : r2c);
364           for (i = 0; i < size; i++)
365                     if (*p++ < 0)
366                               pt[i].id = -1;
367 
368           p = (n == size ? r2c : c2r);
369           FOREACHBIT(mt->touches, slot)
370                     if ((i = *p++) >= 0)
371                               pt[i].id = mt->tracking_ids[slot];
372 }
373 
374 static void
evdev_mt_send_frame(struct evdev_dev * evdev,union evdev_mt_slot * pt,int size)375 evdev_mt_send_frame(struct evdev_dev *evdev, union evdev_mt_slot *pt, int size)
376 {
377           struct evdev_mt *mt = evdev->ev_mt;
378           union evdev_mt_slot *slot;
379 
380           EVDEV_LOCK_ASSERT(evdev);
381           KKASSERT(size >= 0 && size <= MAXIMAL_MT_SLOT(evdev) + 1);
382 
383           /*
384            * While MT-matching assign tracking IDs of new contacts to be equal
385            * to a slot number to make things simpler.
386            */
387           for (slot = pt; slot < pt + size; slot++) {
388                     if (slot->id < 0)
389                               slot->id = ffc_slot(evdev, mt->touches | mt->frame);
390                     if (slot->id >= 0)
391                               evdev_mt_send_slot(evdev, slot->id, slot);
392           }
393 }
394 
395 int
evdev_mt_push_frame(struct evdev_dev * evdev,union evdev_mt_slot * pt,int size)396 evdev_mt_push_frame(struct evdev_dev *evdev, union evdev_mt_slot *pt, int size)
397 {
398           if (size < 0 || size > MAXIMAL_MT_SLOT(evdev) + 1)
399                     return (EINVAL);
400 
401           EVDEV_ENTER(evdev);
402           evdev_mt_send_frame(evdev, pt, size);
403           EVDEV_EXIT(evdev);
404 
405           return (0);
406 }
407 
408 bool
evdev_mt_record_event(struct evdev_dev * evdev,uint16_t type,uint16_t code,int32_t value)409 evdev_mt_record_event(struct evdev_dev *evdev, uint16_t type, uint16_t code,
410     int32_t value)
411 {
412           struct evdev_mt *mt = evdev->ev_mt;
413 
414           EVDEV_LOCK_ASSERT(evdev);
415 
416           switch (type) {
417           case EV_SYN:
418                     if (code == SYN_MT_REPORT) {
419                               /* MT protocol type A support */
420                               KASSERT(mt->type_a, ("Not a MT type A protocol"));
421                               mt->match_frame |= 1U << mt->match_slot;
422                               mt->match_slot++;
423                               return (true);
424                     }
425                     break;
426           case EV_ABS:
427                     if (code == ABS_MT_SLOT) {
428                               /* MT protocol type B support */
429                               KASSERT(!mt->type_a, ("Not a MT type B protocol"));
430                               KASSERT(value >= 0, ("Negative slot number"));
431                               mt->match_slot = value;
432                               mt->match_frame |= 1U << mt->match_slot;
433                               return (true);
434                     } else if (code == ABS_MT_TRACKING_ID) {
435                               KASSERT(!mt->type_a, ("Not a MT type B protocol"));
436                               if (value == -1)
437                                         mt->match_frame &= ~(1U << mt->match_slot);
438                               return (true);
439                     } else if (ABS_IS_MT(code)) {
440                               KASSERT(mt->match_slot >= 0, ("Negative slot"));
441                               KASSERT(mt->match_slot <= MAXIMAL_MT_SLOT(evdev),
442                                   ("Slot number too big"));
443                               mt->match_slots[mt->match_slot].
444                                   val[ABS_MT_INDEX(code)] = value;
445                               return (true);
446                     }
447                     break;
448           default:
449                     break;
450           }
451 
452           return (false);
453 }
454 
455 static void
evdev_mt_replay_events(struct evdev_dev * evdev)456 evdev_mt_replay_events(struct evdev_dev *evdev)
457 {
458           struct evdev_mt *mt = evdev->ev_mt;
459           int slot, size = 0;
460 
461           EVDEV_LOCK_ASSERT(evdev);
462 
463           FOREACHBIT(mt->match_frame, slot) {
464                     if (slot != size)
465                               mt->match_slots[size] = mt->match_slots[slot];
466                     size++;
467           }
468           evdev_mt_match_frame(evdev, mt->match_slots, size);
469           evdev_mt_send_frame(evdev, mt->match_slots, size);
470           mt->match_slot = 0;
471           mt->match_frame = 0;
472 }
473 
474 union evdev_mt_slot *
evdev_mt_get_match_slots(struct evdev_dev * evdev)475 evdev_mt_get_match_slots(struct evdev_dev *evdev)
476 {
477           return (evdev->ev_mt->match_slots);
478 }
479 
480 int
evdev_mt_get_last_slot(struct evdev_dev * evdev)481 evdev_mt_get_last_slot(struct evdev_dev *evdev)
482 {
483 
484           return (evdev->ev_mt->last_reported_slot);
485 }
486 
487 void
evdev_mt_set_last_slot(struct evdev_dev * evdev,int32_t slot)488 evdev_mt_set_last_slot(struct evdev_dev *evdev, int32_t slot)
489 {
490           struct evdev_mt *mt = evdev->ev_mt;
491 
492           KKASSERT(slot >= 0 && slot <= MAXIMAL_MT_SLOT(evdev));
493 
494           mt->frame |= 1U << slot;
495           mt->last_reported_slot = slot;
496 }
497 
498 int32_t
evdev_mt_get_value(struct evdev_dev * evdev,int32_t slot,int16_t code)499 evdev_mt_get_value(struct evdev_dev *evdev, int32_t slot, int16_t code)
500 {
501           struct evdev_mt *mt = evdev->ev_mt;
502 
503           KKASSERT(slot >= 0 && slot <= MAXIMAL_MT_SLOT(evdev));
504 
505           return (mt->slots[slot].val[ABS_MT_INDEX(code)]);
506 }
507 
508 void
evdev_mt_set_value(struct evdev_dev * evdev,int32_t slot,int16_t code,int32_t value)509 evdev_mt_set_value(struct evdev_dev *evdev, int32_t slot, int16_t code,
510     int32_t value)
511 {
512           struct evdev_mt *mt = evdev->ev_mt;
513 
514           KKASSERT(slot >= 0 && slot <= MAXIMAL_MT_SLOT(evdev));
515 
516           if (code == ABS_MT_TRACKING_ID) {
517                     if (value != -1)
518                               mt->touches |= 1U << slot;
519                     else
520                               mt->touches &= ~(1U << slot);
521           }
522           mt->slots[slot].val[ABS_MT_INDEX(code)] = value;
523 }
524 
525 int
evdev_mt_id_to_slot(struct evdev_dev * evdev,int32_t tracking_id)526 evdev_mt_id_to_slot(struct evdev_dev *evdev, int32_t tracking_id)
527 {
528           struct evdev_mt *mt = evdev->ev_mt;
529           int slot;
530 
531           KASSERT(!mt->type_a, ("Not a MT type B protocol"));
532 
533           /*
534            * Ignore tracking_id if slot assignment is performed by evdev.
535            * Events are written sequentially to temporary matching buffer.
536            */
537           if (bit_test(evdev->ev_flags, EVDEV_FLAG_MT_TRACK))
538                     return (ffc_slot(evdev, mt->match_frame));
539 
540           FOREACHBIT(mt->touches, slot)
541                     if (mt->tracking_ids[slot] == tracking_id)
542                               return (slot);
543           /*
544            * Do not allow allocation of new slot in a place of just
545            * released one within the same report.
546            */
547           return (ffc_slot(evdev, mt->touches | mt->frame));
548 }
549 
550 int32_t
evdev_mt_reassign_id(struct evdev_dev * evdev,int slot,int32_t id)551 evdev_mt_reassign_id(struct evdev_dev *evdev, int slot, int32_t id)
552 {
553           struct evdev_mt *mt = evdev->ev_mt;
554           int32_t nid;
555 
556           if (id == -1 || bit_test(evdev->ev_flags, EVDEV_FLAG_MT_KEEPID)) {
557                     mt->tracking_ids[slot] = id;
558                     return (id);
559           }
560 
561           nid = evdev_mt_get_value(evdev, slot, ABS_MT_TRACKING_ID);
562           if (nid != -1) {
563                     KASSERT(id == mt->tracking_ids[slot],
564                         ("MT-slot tracking id has changed"));
565                     return (nid);
566           }
567 
568           mt->tracking_ids[slot] = id;
569 again:
570           nid = mt->tracking_id++;
571           FOREACHBIT(mt->touches, slot)
572                     if (evdev_mt_get_value(evdev, slot, ABS_MT_TRACKING_ID) == nid)
573                               goto again;
574 
575           return (nid);
576 }
577 
578 static inline int32_t
evdev_mt_normalize(int32_t value,int32_t mtmin,int32_t mtmax,int32_t stmax)579 evdev_mt_normalize(int32_t value, int32_t mtmin, int32_t mtmax, int32_t stmax)
580 {
581           if (stmax != 0 && mtmax != mtmin) {
582                     value = (value - mtmin) * stmax / (mtmax - mtmin);
583                     value = MAX(MIN(value, stmax), 0);
584           }
585           return (value);
586 }
587 
588 static void
evdev_mt_support_st_compat(struct evdev_dev * evdev)589 evdev_mt_support_st_compat(struct evdev_dev *evdev)
590 {
591           struct input_absinfo *ai;
592           int i;
593 
594           if (evdev->ev_absinfo == NULL)
595                     return;
596 
597           evdev_support_event(evdev, EV_KEY);
598           evdev_support_key(evdev, BTN_TOUCH);
599 
600           /* Touchscreens should not advertise tap tool capabilities */
601           if (!bit_test(evdev->ev_prop_flags, INPUT_PROP_DIRECT))
602                     evdev_support_nfingers(evdev, MAXIMAL_MT_SLOT(evdev) + 1);
603 
604           /* Echo 0-th MT-slot as ST-slot */
605           for (i = 0; i < nitems(evdev_mtstmap); i++) {
606                     if (!bit_test(evdev->ev_abs_flags, evdev_mtstmap[i].mt) ||
607                          bit_test(evdev->ev_abs_flags, evdev_mtstmap[i].st))
608                               continue;
609                     ai = evdev->ev_absinfo + evdev_mtstmap[i].mt;
610                     evdev->ev_mt->mtst_events |= 1U << i;
611                     if (evdev_mtstmap[i].max != 0)
612                               evdev_support_abs(evdev, evdev_mtstmap[i].st,
613                                   0,
614                                   evdev_mtstmap[i].max,
615                                   0,
616                                   evdev_mt_normalize(
617                                     ai->flat, 0, ai->maximum, evdev_mtstmap[i].max),
618                                   0);
619                     else
620                               evdev_support_abs(evdev, evdev_mtstmap[i].st,
621                                   ai->minimum,
622                                   ai->maximum,
623                                   0,
624                                   ai->flat,
625                                   ai->resolution);
626           }
627 }
628 
629 static void
evdev_mt_send_st_compat(struct evdev_dev * evdev)630 evdev_mt_send_st_compat(struct evdev_dev *evdev)
631 {
632           struct evdev_mt *mt = evdev->ev_mt;
633           int nfingers, i, st_slot;
634 
635           EVDEV_LOCK_ASSERT(evdev);
636 
637           nfingers = bitcount32(mt->touches);
638           evdev_send_event(evdev, EV_KEY, BTN_TOUCH, nfingers > 0);
639 
640           /* Send first active MT-slot state as single touch report */
641           st_slot = ffs(mt->touches) - 1;
642           if (st_slot != -1)
643                     FOREACHBIT(mt->mtst_events, i)
644                               evdev_send_event(evdev, EV_ABS, evdev_mtstmap[i].st,
645                                   evdev_mt_normalize(evdev_mt_get_value(evdev,
646                                     st_slot, evdev_mtstmap[i].mt),
647                                     evdev->ev_absinfo[evdev_mtstmap[i].mt].minimum,
648                                     evdev->ev_absinfo[evdev_mtstmap[i].mt].maximum,
649                                     evdev_mtstmap[i].max));
650 
651           /* Touchscreens should not report tool taps */
652           if (!bit_test(evdev->ev_prop_flags, INPUT_PROP_DIRECT))
653                     evdev_send_nfingers(evdev, nfingers);
654 
655           if (nfingers == 0)
656                     evdev_send_event(evdev, EV_ABS, ABS_PRESSURE, 0);
657 }
658 
659 static void
evdev_mt_send_autorel(struct evdev_dev * evdev)660 evdev_mt_send_autorel(struct evdev_dev *evdev)
661 {
662           struct evdev_mt *mt = evdev->ev_mt;
663           int slot;
664 
665           EVDEV_LOCK_ASSERT(evdev);
666           KASSERT(mt->match_frame == 0, ("Unmatched events exist"));
667 
668           FOREACHBIT(mt->touches & ~mt->frame, slot)
669                     evdev_mt_send_slot(evdev, slot, NULL);
670 }
671 
672 void
evdev_mt_push_autorel(struct evdev_dev * evdev)673 evdev_mt_push_autorel(struct evdev_dev *evdev)
674 {
675           EVDEV_ENTER(evdev);
676           evdev_mt_send_autorel(evdev);
677           EVDEV_EXIT(evdev);
678 }
679