Bug Summary

File:obj-scan-build/../device/chario.c
Location:line 1016, column 3
Description:Value stored to 'count' is never read

Annotated Source Code

1/*
2 * Mach Operating System
3 * Copyright (c) 1993-1988 Carnegie Mellon University
4 * All Rights Reserved.
5 *
6 * Permission to use, copy, modify and distribute this software and its
7 * documentation is hereby granted, provided that both the copyright
8 * notice and this permission notice appear in all copies of the
9 * software, derivative works or modified versions, and any portions
10 * thereof, and that both notices appear in supporting documentation.
11 *
12 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
13 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
14 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
15 *
16 * Carnegie Mellon requests users of this software to return to
17 *
18 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
19 * School of Computer Science
20 * Carnegie Mellon University
21 * Pittsburgh PA 15213-3890
22 *
23 * any improvements or extensions that they make and grant Carnegie Mellon
24 * the rights to redistribute these changes.
25 */
26/*
27 * Author: David B. Golub, Carnegie Mellon University
28 * Date: 8/88
29 *
30 * TTY io.
31 * Compatibility with old TTY device drivers.
32 */
33
34#include <mach/kern_return.h>
35#include <mach/mig_errors.h>
36#include <mach/vm_param.h>
37#include <machine/machspl.h> /* spl definitions */
38
39#include <ipc/ipc_port.h>
40
41#include <kern/lock.h>
42#include <kern/queue.h>
43
44#include <vm/vm_map.h>
45#include <vm/vm_kern.h>
46#include <vm/vm_user.h>
47
48#include <device/device_types.h>
49#include <device/io_req.h>
50#include <device/ds_routines.h>
51#include <device/device_reply.user.h>
52
53#include <device/tty.h>
54
55/* If you change these, check that tty_outq_size and tty_inq_size
56 * is greater than largest tthiwat entry.
57 */
58short tthiwat[NSPEEDS18] =
59 { 100,100,100,100,100,100,100,200,200,400,400,400,650,650,1300,2000,
60 2000,2000 };
61short ttlowat[NSPEEDS18] =
62 { 30, 30, 30, 30, 30, 30, 30, 50, 50,120,120,120,125,125, 125, 125,
63 125,125 };
64
65/*
66 * forward declarations
67 */
68void queue_delayed_reply(
69 queue_t, io_req_t, boolean_t (*)(io_req_t));
70void tty_output(struct tty *);
71boolean_t char_open_done(io_req_t);
72boolean_t char_read_done(io_req_t);
73boolean_t char_write_done(io_req_t);
74
75/*
76 * Fake 'line discipline' switch for the benefit of old code
77 * that wants to call through it.
78 */
79struct ldisc_switch linesw[] = {
80 {
81 char_read,
82 char_write,
83 ttyinput,
84 ttymodem,
85 tty_output
86 }
87};
88
89/*
90 * Sizes for input and output circular buffers.
91 */
92const int tty_inq_size = 4096; /* big nuf */
93const int tty_outq_size = 2048; /* Must be bigger that tthiwat */
94int pdma_default = 1; /* turn pseudo dma on by default */
95
96/*
97 * compute pseudo-dma tables
98 */
99
100int pdma_timeouts[NSPEEDS18]; /* how many ticks in timeout */
101int pdma_water_mark[NSPEEDS18];
102
103
104void chario_init(void)
105{
106 /* the basic idea with the timeouts is two allow enough
107 time for a character to show up if data is coming in at full data rate
108 plus a little slack. 2 ticks is considered slack
109 Below 300 baud we just glob a character at a time */
110#define _PR(x)(0.20 * x) ((hz/x) + 2)
111
112 int i;
113
114 for (i = B00; i < B3007; i++)
115 pdma_timeouts[i] = 0;
116
117 pdma_timeouts[B3007] = _PR(30)(0.20 * 30);
118 pdma_timeouts[B6008] = _PR(60)(0.20 * 60);
119 pdma_timeouts[B12009] = _PR(120)(0.20 * 120);
120 pdma_timeouts[B180010] = _PR(180)(0.20 * 180);
121 pdma_timeouts[B240011] = _PR(240)(0.20 * 240);
122 pdma_timeouts[B480012] = _PR(480)(0.20 * 480);
123 pdma_timeouts[B960013] = _PR(960)(0.20 * 960);
124 pdma_timeouts[EXTA14] = _PR(1440)(0.20 * 1440); /* >14400 baud */
125 pdma_timeouts[EXTB15] = _PR(1920)(0.20 * 1920); /* >19200 baud */
126 pdma_timeouts[B5760016] = _PR(5760)(0.20 * 5760);
127 pdma_timeouts[B11520017] = _PR(11520)(0.20 * 11520);
128
129 for (i = B00; i < B3007; i++)
130 pdma_water_mark[i] = 0;
131
132 /* for the slow speeds, we try to buffer 0.02 of the baud rate
133 (20% of the character rate). For the faster lines,
134 we try to buffer 1/2 the input queue size */
135
136#undef _PR
137#define _PR(x)(0.20 * x) (0.20 * x)
138
139 pdma_water_mark[B3007] = _PR(120)(0.20 * 120);
140 pdma_water_mark[B6008] = _PR(120)(0.20 * 120);
141 pdma_water_mark[B12009] = _PR(120)(0.20 * 120);
142 pdma_water_mark[B180010] = _PR(180)(0.20 * 180);
143 pdma_water_mark[B240011] = _PR(240)(0.20 * 240);
144 pdma_water_mark[B480012] = _PR(480)(0.20 * 480);
145 i = tty_inq_size/2;
146 pdma_water_mark[B960013] = i;
147 pdma_water_mark[EXTA14] = i; /* >14400 baud */
148 pdma_water_mark[EXTB15] = i; /* >19200 baud */
149 pdma_water_mark[B5760016] = i;
150 pdma_water_mark[B11520017] = i;
151
152 return;
153}
154
155/*
156 * Open TTY, waiting for CARR_ON.
157 * No locks may be held.
158 * May run on any CPU.
159 */
160io_return_t char_open(
161 int dev,
162 struct tty * tp,
163 dev_mode_t mode,
164 io_req_t ior)
165{
166 spl_t s;
167 io_return_t rc = D_SUCCESS0;
168
169 s = spltty();
170 simple_lock(&tp->t_lock);
171
172 tp->t_dev = dev;
173
174 if (tp->t_mctl)
175 (*tp->t_mctl)(tp, TM_DTR0x0002, DMSET0);
176
177 if (pdma_default)
178 tp->t_state |= TS_MIN0x00004000;
179
180 if ((tp->t_state & TS_CARR_ON0x00000020) == 0) {
181 /*
182 * No carrier.
183 */
184 if (mode & D_NODELAY0x4) {
185 tp->t_state |= TS_ONDELAY0x00002000;
186 }
187 else {
188 /*
189 * Don`t return from open until carrier detected.
190 */
191 tp->t_state |= TS_WOPEN0x00000004;
192
193 ior->io_dev_ptr = (char *)tp;
194
195 queue_delayed_reply(&tp->t_delayed_open, ior, char_open_done);
196 rc = D_IO_QUEUED(-1);
197 goto out;
198 }
199 }
200 tp->t_state |= TS_ISOPEN0x00000008;
201 if (tp->t_mctl)
202 (*tp->t_mctl)(tp, TM_RTS0x0004, DMBIS1);
203out:
204 simple_unlock(&tp->t_lock);
205 splx(s);
206 return rc;
207}
208
209/*
210 * Retry wait for CARR_ON for open.
211 * No locks may be held.
212 * May run on any CPU.
213 */
214boolean_t char_open_done(
215 io_req_t ior)
216{
217 struct tty *tp = (struct tty *)ior->io_dev_ptr;
218 spl_t s = spltty();
219
220 simple_lock(&tp->t_lock);
221 if ((tp->t_state & TS_ISOPEN0x00000008) == 0) {
222 queue_delayed_reply(&tp->t_delayed_open, ior, char_open_done);
223 simple_unlock(&tp->t_lock);
224 splx(s);
225 return FALSE((boolean_t) 0);
226 }
227
228 tp->t_state |= TS_ISOPEN0x00000008;
229 tp->t_state &= ~TS_WOPEN0x00000004;
230
231 if (tp->t_mctl)
232 (*tp->t_mctl)(tp, TM_RTS0x0004, DMBIS1);
233
234 simple_unlock(&tp->t_lock);
235 splx(s);
236
237 ior->io_error = D_SUCCESS0;
238 (void) ds_open_done(ior);
239 return TRUE((boolean_t) 1);
240}
241
242boolean_t tty_close_open_reply(
243 io_req_t ior)
244{
245 ior->io_error = D_DEVICE_DOWN2504;
246 (void) ds_open_done(ior);
247 return TRUE((boolean_t) 1);
248}
249
250/*
251 * Write to TTY.
252 * No locks may be held.
253 * Calls device start routine; must already be on master if
254 * device needs to run on master.
255 */
256io_return_t char_write(
257 struct tty * tp,
258 io_req_t ior)
259{
260 spl_t s;
261 int count;
262 char *data;
263 vm_offset_t addr = 0;
264 io_return_t rc = D_SUCCESS0;
265
266 data = ior->io_dataio_un.data;
267 count = ior->io_count;
268 if (count == 0)
269 return rc;
270
271 if (!(ior->io_op & IO_INBAND0x00004000)) {
272 /*
273 * Copy out-of-line data into kernel address space.
274 * Since data is copied as page list, it will be
275 * accessible.
276 */
277 vm_map_copy_t copy = (vm_map_copy_t) data;
278 kern_return_t kr;
279
280 kr = vm_map_copyout(device_io_map, &addr, copy);
281 if (kr != KERN_SUCCESS0)
282 return kr;
283 data = (char *) addr;
284 }
285
286 /*
287 * Check for tty operating.
288 */
289 s = spltty();
290 simple_lock(&tp->t_lock);
291
292 if ((tp->t_state & TS_CARR_ON0x00000020) == 0) {
293
294 if ((tp->t_state & TS_ONDELAY0x00002000) == 0) {
295 /*
296 * No delayed writes - tell caller that device is down
297 */
298 rc = D_IO_ERROR2500;
299 goto out;
300 }
301
302 if (ior->io_mode & D_NOWAIT0x8) {
303 rc = D_WOULD_BLOCK2501;
304 goto out;
305 }
306 }
307
308 /*
309 * Copy data into the output buffer.
310 * Report the amount not copied.
311 */
312
313 ior->io_residual = b_to_q(data, count, &tp->t_outq);
314
315 /*
316 * Start hardware output.
317 */
318
319 tp->t_state &= ~TS_TTSTOP0x00000100;
320 tty_output(tp);
321
322 if (tp->t_outq.c_cc > TTHIWAT(tp)tthiwat[(tp)->t_ospeed] ||
323 (tp->t_state & TS_CARR_ON0x00000020) == 0) {
324
325 /*
326 * Do not send reply until some characters have been sent.
327 */
328 ior->io_dev_ptr = (char *)tp;
329 queue_delayed_reply(&tp->t_delayed_write, ior, char_write_done);
330
331 rc = D_IO_QUEUED(-1);
332 }
333out:
334 simple_unlock(&tp->t_lock);
335 splx(s);
336
337 if (!(ior->io_op & IO_INBAND0x00004000))
338 (void) vm_deallocate(device_io_map, addr, ior->io_count);
339 return rc;
340}
341
342/*
343 * Retry wait for output queue emptied, for write.
344 * No locks may be held.
345 * May run on any CPU.
346 */
347boolean_t char_write_done(
348 io_req_t ior)
349{
350 struct tty *tp = (struct tty *)ior->io_dev_ptr;
351 spl_t s = spltty();
352
353 simple_lock(&tp->t_lock);
354 if (tp->t_outq.c_cc > TTHIWAT(tp)tthiwat[(tp)->t_ospeed] ||
355 (tp->t_state & TS_CARR_ON0x00000020) == 0) {
356
357 queue_delayed_reply(&tp->t_delayed_write, ior, char_write_done);
358 simple_unlock(&tp->t_lock);
359 splx(s);
360 return FALSE((boolean_t) 0);
361 }
362 simple_unlock(&tp->t_lock);
363 splx(s);
364
365 if (IP_VALID(ior->io_reply_port)(((&(ior->io_reply_port)->ip_target.ipt_object) != (
(ipc_object_t) 0)) && ((&(ior->io_reply_port)->
ip_target.ipt_object) != ((ipc_object_t) -1)))) {
366 (void) (*((ior->io_op & IO_INBAND0x00004000) ?
367 ds_device_write_reply_inband :
368 ds_device_write_reply))(ior->io_reply_port,
369 ior->io_reply_port_type,
370 ior->io_error,
371 (int) (ior->io_total -
372 ior->io_residual));
373 }
374 mach_device_deallocate(ior->io_device);
375 return TRUE((boolean_t) 1);
376}
377
378boolean_t tty_close_write_reply(
379 io_req_t ior)
380{
381 ior->io_residual = ior->io_count;
382 ior->io_error = D_DEVICE_DOWN2504;
383 (void) ds_write_done(ior);
384 return TRUE((boolean_t) 1);
385}
386
387/*
388 * Read from TTY.
389 * No locks may be held.
390 * May run on any CPU - does not talk to device driver.
391 */
392io_return_t char_read(
393 struct tty *tp,
394 io_req_t ior)
395{
396 spl_t s;
397 kern_return_t rc;
398
399 /*
400 * Allocate memory for read buffer.
401 */
402 rc = device_read_alloc(ior, (vm_size_t)ior->io_count);
403 if (rc != KERN_SUCCESS0)
404 return rc;
405
406 s = spltty();
407 simple_lock(&tp->t_lock);
408 if ((tp->t_state & TS_CARR_ON0x00000020) == 0) {
409
410 if ((tp->t_state & TS_ONDELAY0x00002000) == 0) {
411 /*
412 * No delayed writes - tell caller that device is down
413 */
414 rc = D_IO_ERROR2500;
415 goto out;
416 }
417
418 if (ior->io_mode & D_NOWAIT0x8) {
419 rc = D_WOULD_BLOCK2501;
420 goto out;
421 }
422
423 }
424
425 if (tp->t_inq.c_cc <= 0 ||
426 (tp->t_state & TS_CARR_ON0x00000020) == 0) {
427
428 ior->io_dev_ptr = (char *)tp;
429 queue_delayed_reply(&tp->t_delayed_read, ior, char_read_done);
430 rc = D_IO_QUEUED(-1);
431 goto out;
432 }
433
434 ior->io_residual = ior->io_count - q_to_b(&tp->t_inq,
435 ior->io_dataio_un.data,
436 (int)ior->io_count);
437 if (tp->t_state & TS_RTS_DOWN0x00020000) {
438 (*tp->t_mctl)(tp, TM_RTS0x0004, DMBIS1);
439 tp->t_state &= ~TS_RTS_DOWN0x00020000;
440 }
441
442 out:
443 simple_unlock(&tp->t_lock);
444 splx(s);
445 return rc;
446}
447
448/*
449 * Retry wait for characters, for read.
450 * No locks may be held.
451 * May run on any CPU - does not talk to device driver.
452 */
453boolean_t char_read_done(
454 io_req_t ior)
455{
456 struct tty *tp = (struct tty *)ior->io_dev_ptr;
457 spl_t s = spltty();
458
459 simple_lock(&tp->t_lock);
460
461 if (tp->t_inq.c_cc <= 0 ||
462 (tp->t_state & TS_CARR_ON0x00000020) == 0) {
463
464 queue_delayed_reply(&tp->t_delayed_read, ior, char_read_done);
465 simple_unlock(&tp->t_lock);
466 splx(s);
467 return FALSE((boolean_t) 0);
468 }
469
470 ior->io_residual = ior->io_count - q_to_b(&tp->t_inq,
471 ior->io_dataio_un.data,
472 (int)ior->io_count);
473 if (tp->t_state & TS_RTS_DOWN0x00020000) {
474 (*tp->t_mctl)(tp, TM_RTS0x0004, DMBIS1);
475 tp->t_state &= ~TS_RTS_DOWN0x00020000;
476 }
477
478 simple_unlock(&tp->t_lock);
479 splx(s);
480
481 (void) ds_read_done(ior);
482 return TRUE((boolean_t) 1);
483}
484
485boolean_t tty_close_read_reply(
486 io_req_t ior)
487{
488 ior->io_residual = ior->io_count;
489 ior->io_error = D_DEVICE_DOWN2504;
490 (void) ds_read_done(ior);
491 return TRUE((boolean_t) 1);
492}
493
494/*
495 * Close the tty.
496 * Tty must be locked (at spltty).
497 * Iff modem control should run on master.
498 */
499void ttyclose(
500 struct tty *tp)
501{
502 io_req_t ior;
503
504 /*
505 * Flush the read and write queues. Signal
506 * the open queue so that those waiting for open
507 * to complete will see that the tty is closed.
508 */
509 while ((ior = (io_req_t)dequeue_head(&tp->t_delayed_read)) != 0) {
510 ior->io_done = tty_close_read_reply;
511 iodone(ior);
512 }
513 while ((ior = (io_req_t)dequeue_head(&tp->t_delayed_write)) != 0) {
514 ior->io_done = tty_close_write_reply;
515 iodone(ior);
516 }
517 while ((ior = (io_req_t)dequeue_head(&tp->t_delayed_open)) != 0) {
518 ior->io_done = tty_close_open_reply;
519 iodone(ior);
520 }
521
522 /* Close down modem */
523 if (tp->t_mctl) {
524 (*tp->t_mctl)(tp, TM_BRK0x0200|TM_RTS0x0004, DMBIC2);
525 if ((tp->t_state&(TS_HUPCLS0x00000200|TS_WOPEN0x00000004)) || (tp->t_state&TS_ISOPEN0x00000008)==0)
526 (*tp->t_mctl)(tp, TM_HUP0x0000, DMSET0);
527 }
528
529 /* only save buffering bit, and carrier */
530 tp->t_state = tp->t_state & (TS_MIN0x00004000|TS_CARR_ON0x00000020);
531}
532
533/*
534 * Port-death routine to clean up reply messages.
535 */
536boolean_t
537tty_queue_clean(
538 queue_t q,
539 ipc_port_t port,
540 boolean_t (*routine)(io_req_t) )
541{
542 io_req_t ior;
543
544 ior = (io_req_t)queue_first(q)((q)->next);
545 while (!queue_end(q, (queue_entry_t)ior)((q) == ((queue_entry_t)ior))) {
546 if (ior->io_reply_port == port) {
547 remqueue(q, (queue_entry_t)ior);
548 ior->io_done = routine;
549 iodone(ior);
550 return TRUE((boolean_t) 1);
551 }
552 ior = ior->io_next;
553 }
554 return FALSE((boolean_t) 0);
555}
556
557/*
558 * Handle port-death (dead reply port) for tty.
559 * No locks may be held.
560 * May run on any CPU.
561 */
562boolean_t
563tty_portdeath(
564 struct tty * tp,
565 ipc_port_t port)
566{
567 spl_t spl = spltty();
568 boolean_t result;
569
570 simple_lock(&tp->t_lock);
571
572 /*
573 * The queues may never have been initialized
574 */
575 if (tp->t_delayed_read.next == 0) {
576 result = FALSE((boolean_t) 0);
577 }
578 else {
579 result =
580 tty_queue_clean(&tp->t_delayed_read, port,
581 tty_close_read_reply)
582 || tty_queue_clean(&tp->t_delayed_write, port,
583 tty_close_write_reply)
584 || tty_queue_clean(&tp->t_delayed_open, port,
585 tty_close_open_reply);
586 }
587 simple_unlock(&tp->t_lock);
588 splx(spl);
589
590 return result;
591}
592
593/*
594 * Get TTY status.
595 * No locks may be held.
596 * May run on any CPU.
597 */
598io_return_t tty_get_status(
599 struct tty *tp,
600 dev_flavor_t flavor,
601 int * data, /* pointer to OUT array */
602 natural_t *count) /* out */
603{
604 spl_t s;
605
606 switch (flavor) {
607 case TTY_STATUS(dev_flavor_t)(('t'<<16) + 1):
608 {
609 struct tty_status *tsp =
610 (struct tty_status *) data;
611
612 if (*count < TTY_STATUS_COUNT(sizeof(struct tty_status)/sizeof(int)))
613 return (D_INVALID_OPERATION2505);
614
615 s = spltty();
616 simple_lock(&tp->t_lock);
617
618 tsp->tt_ispeed = tp->t_ispeed;
619 tsp->tt_ospeed = tp->t_ospeed;
620 tsp->tt_breakc = tp->t_breakc;
621 tsp->tt_flags = tp->t_flags;
622 if (tp->t_state & TS_HUPCLS0x00000200)
623 tsp->tt_flags |= TF_HUPCLS0x00000040;
624
625 simple_unlock(&tp->t_lock);
626 splx(s);
627
628 *count = TTY_STATUS_COUNT(sizeof(struct tty_status)/sizeof(int));
629 break;
630
631 }
632 default:
633 return D_INVALID_OPERATION2505;
634 }
635 return D_SUCCESS0;
636}
637
638/*
639 * Set TTY status.
640 * No locks may be held.
641 * Calls device start or stop routines; must already be on master if
642 * device needs to run on master.
643 */
644io_return_t tty_set_status(
645 struct tty *tp,
646 dev_flavor_t flavor,
647 int * data,
648 natural_t count)
649{
650 int s;
651
652 switch (flavor) {
653 case TTY_FLUSH(dev_flavor_t)(('t'<<16) + 3):
654 {
655 int flags;
656 if (count < TTY_FLUSH_COUNT(1))
657 return D_INVALID_OPERATION2505;
658
659 flags = *data;
660 if (flags == 0)
661 flags = D_READ0x1 | D_WRITE0x2;
662
663 s = spltty();
664 simple_lock(&tp->t_lock);
665 tty_flush(tp, flags);
666 simple_unlock(&tp->t_lock);
667 splx(s);
668
669 break;
670 }
671 case TTY_STOP(dev_flavor_t)(('t'<<16) + 4):
672 /* stop output */
673 s = spltty();
674 simple_lock(&tp->t_lock);
675 if ((tp->t_state & TS_TTSTOP0x00000100) == 0) {
676 tp->t_state |= TS_TTSTOP0x00000100;
677 (*tp->t_stop)(tp, 0);
678 }
679 simple_unlock(&tp->t_lock);
680 splx(s);
681 break;
682
683 case TTY_START(dev_flavor_t)(('t'<<16) + 5):
684 /* start output */
685 s = spltty();
686 simple_lock(&tp->t_lock);
687 if (tp->t_state & TS_TTSTOP0x00000100) {
688 tp->t_state &= ~TS_TTSTOP0x00000100;
689 tty_output(tp);
690 }
691 simple_unlock(&tp->t_lock);
692 splx(s);
693 break;
694
695 case TTY_STATUS(dev_flavor_t)(('t'<<16) + 1):
696 /* set special characters and speed */
697 {
698 struct tty_status *tsp;
699
700 if (count < TTY_STATUS_COUNT(sizeof(struct tty_status)/sizeof(int)))
701 return D_INVALID_OPERATION2505;
702
703 tsp = (struct tty_status *)data;
704
705 if (tsp->tt_ispeed < 0 ||
706 tsp->tt_ispeed >= NSPEEDS18 ||
707 tsp->tt_ospeed < 0 ||
708 tsp->tt_ospeed >= NSPEEDS18)
709 {
710 return D_INVALID_OPERATION2505;
711 }
712
713 s = spltty();
714 simple_lock(&tp->t_lock);
715
716 tp->t_ispeed = tsp->tt_ispeed;
717 tp->t_ospeed = tsp->tt_ospeed;
718 tp->t_breakc = tsp->tt_breakc;
719 tp->t_flags = tsp->tt_flags & ~TF_HUPCLS0x00000040;
720 if (tsp->tt_flags & TF_HUPCLS0x00000040)
721 tp->t_state |= TS_HUPCLS0x00000200;
722
723 simple_unlock(&tp->t_lock);
724 splx(s);
725 break;
726 }
727 default:
728 return D_INVALID_OPERATION2505;
729 }
730 return D_SUCCESS0;
731}
732
733
734/*
735 * [internal]
736 * Queue IOR on reply queue, to wait for TTY operation.
737 * TTY must be locked (at spltty).
738 */
739void queue_delayed_reply(
740 queue_t qh,
741 io_req_t ior,
742 boolean_t (*io_done)(io_req_t) )
743{
744 ior->io_done = io_done;
745 enqueue_tail(qh, (queue_entry_t)ior);
746}
747
748/*
749 * Retry delayed IO operations for TTY.
750 * TTY containing queue must be locked (at spltty).
751 */
752void tty_queue_completion(
753 queue_t qh)
754{
755 io_req_t ior;
756
757 while ((ior = (io_req_t)dequeue_head(qh)) != 0) {
758 iodone(ior);
759 }
760}
761
762/*
763 * Set the default special characters.
764 * Since this routine is called whenever a tty has never been opened,
765 * we can initialize the queues here.
766 */
767void ttychars(
768 struct tty *tp)
769{
770 if ((tp->t_flags & TS_INIT0x00000001) == 0) {
771 /*
772 * Initialize queues
773 */
774 queue_init(&tp->t_delayed_open)((&tp->t_delayed_open)->next = (&tp->t_delayed_open
)->prev = &tp->t_delayed_open);
775 queue_init(&tp->t_delayed_read)((&tp->t_delayed_read)->next = (&tp->t_delayed_read
)->prev = &tp->t_delayed_read);
776 queue_init(&tp->t_delayed_write)((&tp->t_delayed_write)->next = (&tp->t_delayed_write
)->prev = &tp->t_delayed_write);
777
778 /*
779 * Initialize character buffers
780 */
781 cb_alloc(&tp->t_inq, tty_inq_size);
782
783 /* if we might do modem flow control */
784 if (tp->t_mctl && tp->t_inq.c_hog > 30)
785 tp->t_inq.c_hog -= 30;
786
787 cb_alloc(&tp->t_outq, tty_outq_size);
788
789 /*
790 * Mark initialized
791 */
792 tp->t_state |= TS_INIT0x00000001;
793 }
794
795 tp->t_breakc = 0;
796}
797
798/*
799 * Flush all TTY queues.
800 * Called at spltty, tty already locked.
801 * Calls device STOP routine; must already be on master if
802 * device needs to run on master.
803 */
804void tty_flush(
805 struct tty *tp,
806 int rw)
807{
808 if (rw & D_READ0x1) {
809 cb_clear(&tp->t_inq);
810 tty_queue_completion(&tp->t_delayed_read);
811 }
812 if (rw & D_WRITE0x2) {
813 tp->t_state &= ~TS_TTSTOP0x00000100;
814 (*tp->t_stop)(tp, rw);
815 cb_clear(&tp->t_outq);
816 tty_queue_completion(&tp->t_delayed_write);
817 }
818}
819
820/*
821 * Restart character output after a delay timeout.
822 * Calls device start routine - must be on master CPU.
823 *
824 * Timeout routines are called only on master CPU.
825 * What if device runs on a different CPU?
826 */
827void ttrstrt(
828 struct tty *tp)
829{
830 spl_t s;
831
832 s = spltty();
833 simple_lock(&tp->t_lock);
834
835 tp->t_state &= ~TS_TIMEOUT0x00000002;
836 ttstart (tp);
837
838 simple_unlock(&tp->t_lock);
839 splx(s);
840}
841
842/*
843 * Start output on the typewriter. It is used from the top half
844 * after some characters have been put on the output queue,
845 * from the interrupt routine to transmit the next
846 * character, and after a timeout has finished.
847 *
848 * Called at spltty, tty already locked.
849 * Must be on master CPU if device runs on master.
850 */
851void ttstart(tp)
852 struct tty *tp;
853{
854 if ((tp->t_state & (TS_TIMEOUT0x00000002|TS_TTSTOP0x00000100|TS_BUSY0x00000040)) == 0) {
855 /*
856 * Start up the hardware again
857 */
858 (*tp->t_start)(tp);
859
860 /*
861 * Wake up those waiting for write completion.
862 */
863 if (tp->t_outq.c_cc <= TTLOWAT(tp)ttlowat[(tp)->t_ospeed])
864 tty_queue_completion(&tp->t_delayed_write);
865 }
866}
867
868/*
869 * Start character output, if the device is not busy or
870 * stopped or waiting for a timeout.
871 *
872 * Called at spltty, tty already locked.
873 * Must be on master CPU if device runs on master.
874 */
875void tty_output(
876 struct tty *tp)
877{
878 if ((tp->t_state & (TS_TIMEOUT0x00000002|TS_TTSTOP0x00000100|TS_BUSY0x00000040)) == 0) {
879 /*
880 * Not busy. Start output.
881 */
882 (*tp->t_start)(tp);
883
884 /*
885 * Wake up those waiting for write completion.
886 */
887 if (tp->t_outq.c_cc <= TTLOWAT(tp)ttlowat[(tp)->t_ospeed])
888 tty_queue_completion(&tp->t_delayed_write);
889 }
890}
891
892/*
893 * Send any buffered recvd chars up to user
894 */
895void ttypush(
896 void * _tp)
897{
898 struct tty *tp = _tp;
899 spl_t s = spltty();
900 int state;
901
902 simple_lock(&tp->t_lock);
903
904 /*
905 The pdma timeout has gone off.
906 If no character has been received since the timeout
907 was set, push any pending characters up.
908 If any characters were received in the last interval
909 then just reset the timeout and the character received bit.
910 */
911
912 state = tp->t_state;
913
914 if (state & TS_MIN_TO0x00008000)
915 {
916 if (state & TS_MIN_TO_RCV0x00400000)
917 { /* a character was received */
918 tp->t_state = state & ~TS_MIN_TO_RCV0x00400000;
919 timeout(ttypush,tp,pdma_timeouts[tp->t_ispeed]);
920 }
921 else
922 {
923 tp->t_state = state & ~TS_MIN_TO0x00008000;
924 if (tp->t_inq.c_cc) /* pending characters */
925 tty_queue_completion(&tp->t_delayed_read);
926 }
927 }
928 else
929 {
930 tp->t_state = state & ~TS_MIN_TO_RCV0x00400000;/* sanity */
931 }
932
933 simple_unlock(&tp->t_lock);
934 splx(s);
935}
936
937/*
938 * Put input character on input queue.
939 *
940 * Called at spltty, tty already locked.
941 */
942void ttyinput(
943 unsigned int c,
944 struct tty *tp)
945{
946 if (tp->t_inq.c_cc >= tp->t_inq.c_hog) {
947 /*
948 * Do not want to overflow input queue
949 */
950 if (tp->t_mctl) {
951 (*tp->t_mctl)(tp, TM_RTS0x0004, DMBIC2);
952 tp->t_state |= TS_RTS_DOWN0x00020000;
953 }
954 tty_queue_completion(&tp->t_delayed_read);
955 return;
956
957 }
958
959 c &= 0xff;
960
961 (void) putc(c, &tp->t_inq);
962 if ((tp->t_state & TS_MIN0x00004000) == 0 ||
963 tp->t_inq.c_cc > pdma_water_mark[tp->t_ispeed])
964 {
965 /*
966 * No input buffering, or input minimum exceeded.
967 * Grab a request from input queue and queue it
968 * to io_done thread.
969 */
970 if (tp->t_state & TS_MIN_TO0x00008000) {
971 tp->t_state &= ~(TS_MIN_TO0x00008000|TS_MIN_TO_RCV0x00400000);
972 untimeout(ttypush, tp);
973 }
974 tty_queue_completion(&tp->t_delayed_read);
975 }
976 else {
977 /*
978 * Not enough characters.
979 * If no timeout is set, initiate the timeout
980 * Otherwise set the character received during timeout interval
981 * flag.
982 * One alternative approach would be just to reset the timeout
983 * into the future, but this involves making a timeout/untimeout
984 * call on every character.
985 */
986 int ptime = pdma_timeouts[tp->t_ispeed];
987 if (ptime > 0)
988 {
989 if ((tp->t_state & TS_MIN_TO0x00008000) == 0)
990 {
991 tp->t_state |= TS_MIN_TO0x00008000;
992 timeout(ttypush, tp, ptime);
993 }
994 else
995 {
996 tp->t_state |= TS_MIN_TO_RCV0x00400000;
997 }
998 }
999 }
1000}
1001
1002/*
1003 * Put many characters on input queue.
1004 *
1005 * Called at spltty, tty already locked.
1006 */
1007void ttyinput_many(
1008 struct tty *tp,
1009 char *chars,
1010 int count)
1011{
1012 /*
1013 * Do not want to overflow input queue
1014 */
1015 if (tp->t_inq.c_cc < tp->t_inq.c_hog)
1016 count -= b_to_q( chars, count, &tp->t_inq);
Value stored to 'count' is never read
1017
1018 tty_queue_completion(&tp->t_delayed_read);
1019}
1020
1021
1022/*
1023 * Handle modem control transition on a tty.
1024 * Flag indicates new state of carrier.
1025 * Returns FALSE if the line should be turned off.
1026 *
1027 * Called at spltty, tty already locked.
1028 */
1029boolean_t ttymodem(
1030 struct tty * tp,
1031 boolean_t carrier_up)
1032{
1033 if ((tp->t_state&TS_WOPEN0x00000004) == 0 && (tp->t_flags & MDMBUF0x00000010)) {
1034 /*
1035 * Flow control by carrier. Carrier down stops
1036 * output; carrier up restarts output.
1037 */
1038 if (carrier_up) {
1039 tp->t_state &= ~TS_TTSTOP0x00000100;
1040 tty_output(tp);
1041 }
1042 else if ((tp->t_state&TS_TTSTOP0x00000100) == 0) {
1043 tp->t_state |= TS_TTSTOP0x00000100;
1044 (*tp->t_stop)(tp, 0);
1045 }
1046 }
1047 else if (carrier_up) {
1048 /*
1049 * Carrier now on.
1050 */
1051 tp->t_state |= TS_CARR_ON0x00000020;
1052 tt_open_wakeup(tp)(tty_queue_completion(&(tp)->t_delayed_open));
1053 }
1054 else {
1055 /*
1056 * Lost carrier.
1057 */
1058 tp->t_state &= ~TS_CARR_ON0x00000020;
1059 if (tp->t_state & TS_ISOPEN0x00000008 &&
1060 (tp->t_flags & NOHANG0x00000020) == 0)
1061 {
1062 /*
1063 * Hang up TTY if carrier drops.
1064 * Need to alert users, somehow...
1065 */
1066 tty_flush(tp, D_READ0x1|D_WRITE0x2);
1067 return FALSE((boolean_t) 0);
1068 }
1069 }
1070 return TRUE((boolean_t) 1);
1071}
1072
1073/*
1074 * Similarly, handle transitions on the ClearToSend
1075 * signal. Nowadays, it is used by many modems as
1076 * a flow-control device: they turn it down to stop
1077 * us from sending more chars. We do the same with
1078 * the RequestToSend signal. [Yes, that is exactly
1079 * why those signals are defined in the standard.]
1080 *
1081 * Tty must be locked and on master.
1082 */
1083void
1084tty_cts(
1085 struct tty * tp,
1086 boolean_t cts_up)
1087{
1088 if (tp->t_state & TS_ISOPEN0x00000008){
1089 if (cts_up) {
1090 tp->t_state &= ~(TS_TTSTOP0x00000100|TS_BUSY0x00000040);
1091 tty_output(tp);
1092 } else {
1093 tp->t_state |= (TS_TTSTOP0x00000100|TS_BUSY0x00000040);
1094 (*tp->t_stop)(tp, D_WRITE0x2);
1095 }
1096 }
1097}