treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152
[muen/linux.git] / drivers / isdn / gigaset / interface.c
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * interface to user space for the gigaset driver
4  *
5  * Copyright (c) 2004 by Hansjoerg Lipp <hjlipp@web.de>
6  *
7  * =====================================================================
8  * =====================================================================
9  */
10
11 #include "gigaset.h"
12 #include <linux/gigaset_dev.h>
13 #include <linux/tty_flip.h>
14 #include <linux/module.h>
15
16 /*** our ioctls ***/
17
18 static int if_lock(struct cardstate *cs, int *arg)
19 {
20         int cmd = *arg;
21
22         gig_dbg(DEBUG_IF, "%u: if_lock (%d)", cs->minor_index, cmd);
23
24         if (cmd > 1)
25                 return -EINVAL;
26
27         if (cmd < 0) {
28                 *arg = cs->mstate == MS_LOCKED;
29                 return 0;
30         }
31
32         if (!cmd && cs->mstate == MS_LOCKED && cs->connected) {
33                 cs->ops->set_modem_ctrl(cs, 0, TIOCM_DTR | TIOCM_RTS);
34                 cs->ops->baud_rate(cs, B115200);
35                 cs->ops->set_line_ctrl(cs, CS8);
36                 cs->control_state = TIOCM_DTR | TIOCM_RTS;
37         }
38
39         cs->waiting = 1;
40         if (!gigaset_add_event(cs, &cs->at_state, EV_IF_LOCK,
41                                NULL, cmd, NULL)) {
42                 cs->waiting = 0;
43                 return -ENOMEM;
44         }
45         gigaset_schedule_event(cs);
46
47         wait_event(cs->waitqueue, !cs->waiting);
48
49         if (cs->cmd_result >= 0) {
50                 *arg = cs->cmd_result;
51                 return 0;
52         }
53
54         return cs->cmd_result;
55 }
56
57 static int if_version(struct cardstate *cs, unsigned arg[4])
58 {
59         static const unsigned version[4] = GIG_VERSION;
60         static const unsigned compat[4] = GIG_COMPAT;
61         unsigned cmd = arg[0];
62
63         gig_dbg(DEBUG_IF, "%u: if_version (%d)", cs->minor_index, cmd);
64
65         switch (cmd) {
66         case GIGVER_DRIVER:
67                 memcpy(arg, version, sizeof version);
68                 return 0;
69         case GIGVER_COMPAT:
70                 memcpy(arg, compat, sizeof compat);
71                 return 0;
72         case GIGVER_FWBASE:
73                 cs->waiting = 1;
74                 if (!gigaset_add_event(cs, &cs->at_state, EV_IF_VER,
75                                        NULL, 0, arg)) {
76                         cs->waiting = 0;
77                         return -ENOMEM;
78                 }
79                 gigaset_schedule_event(cs);
80
81                 wait_event(cs->waitqueue, !cs->waiting);
82
83                 if (cs->cmd_result >= 0)
84                         return 0;
85
86                 return cs->cmd_result;
87         default:
88                 return -EINVAL;
89         }
90 }
91
92 static int if_config(struct cardstate *cs, int *arg)
93 {
94         gig_dbg(DEBUG_IF, "%u: if_config (%d)", cs->minor_index, *arg);
95
96         if (*arg != 1)
97                 return -EINVAL;
98
99         if (cs->mstate != MS_LOCKED)
100                 return -EBUSY;
101
102         if (!cs->connected) {
103                 pr_err("%s: not connected\n", __func__);
104                 return -ENODEV;
105         }
106
107         *arg = 0;
108         return gigaset_enterconfigmode(cs);
109 }
110
111 /*** the terminal driver ***/
112
113 static int if_open(struct tty_struct *tty, struct file *filp)
114 {
115         struct cardstate *cs;
116
117         gig_dbg(DEBUG_IF, "%d+%d: %s()",
118                 tty->driver->minor_start, tty->index, __func__);
119
120         cs = gigaset_get_cs_by_tty(tty);
121         if (!cs || !try_module_get(cs->driver->owner))
122                 return -ENODEV;
123
124         if (mutex_lock_interruptible(&cs->mutex)) {
125                 module_put(cs->driver->owner);
126                 return -ERESTARTSYS;
127         }
128         tty->driver_data = cs;
129
130         ++cs->port.count;
131
132         if (cs->port.count == 1) {
133                 tty_port_tty_set(&cs->port, tty);
134                 cs->port.low_latency = 1;
135         }
136
137         mutex_unlock(&cs->mutex);
138         return 0;
139 }
140
141 static void if_close(struct tty_struct *tty, struct file *filp)
142 {
143         struct cardstate *cs = tty->driver_data;
144
145         if (!cs) { /* happens if we didn't find cs in open */
146                 gig_dbg(DEBUG_IF, "%s: no cardstate", __func__);
147                 return;
148         }
149
150         gig_dbg(DEBUG_IF, "%u: %s()", cs->minor_index, __func__);
151
152         mutex_lock(&cs->mutex);
153
154         if (!cs->connected)
155                 gig_dbg(DEBUG_IF, "not connected");     /* nothing to do */
156         else if (!cs->port.count)
157                 dev_warn(cs->dev, "%s: device not opened\n", __func__);
158         else if (!--cs->port.count)
159                 tty_port_tty_set(&cs->port, NULL);
160
161         mutex_unlock(&cs->mutex);
162
163         module_put(cs->driver->owner);
164 }
165
166 static int if_ioctl(struct tty_struct *tty,
167                     unsigned int cmd, unsigned long arg)
168 {
169         struct cardstate *cs = tty->driver_data;
170         int retval = -ENODEV;
171         int int_arg;
172         unsigned char buf[6];
173         unsigned version[4];
174
175         gig_dbg(DEBUG_IF, "%u: %s(0x%x)", cs->minor_index, __func__, cmd);
176
177         if (mutex_lock_interruptible(&cs->mutex))
178                 return -ERESTARTSYS;
179
180         if (!cs->connected) {
181                 gig_dbg(DEBUG_IF, "not connected");
182                 retval = -ENODEV;
183         } else {
184                 retval = 0;
185                 switch (cmd) {
186                 case GIGASET_REDIR:
187                         retval = get_user(int_arg, (int __user *) arg);
188                         if (retval >= 0)
189                                 retval = if_lock(cs, &int_arg);
190                         if (retval >= 0)
191                                 retval = put_user(int_arg, (int __user *) arg);
192                         break;
193                 case GIGASET_CONFIG:
194                         retval = get_user(int_arg, (int __user *) arg);
195                         if (retval >= 0)
196                                 retval = if_config(cs, &int_arg);
197                         if (retval >= 0)
198                                 retval = put_user(int_arg, (int __user *) arg);
199                         break;
200                 case GIGASET_BRKCHARS:
201                         retval = copy_from_user(&buf,
202                                                 (const unsigned char __user *) arg, 6)
203                                 ? -EFAULT : 0;
204                         if (retval >= 0) {
205                                 gigaset_dbg_buffer(DEBUG_IF, "GIGASET_BRKCHARS",
206                                                    6, buf);
207                                 retval = cs->ops->brkchars(cs, buf);
208                         }
209                         break;
210                 case GIGASET_VERSION:
211                         retval = copy_from_user(version,
212                                                 (unsigned __user *) arg, sizeof version)
213                                 ? -EFAULT : 0;
214                         if (retval >= 0)
215                                 retval = if_version(cs, version);
216                         if (retval >= 0)
217                                 retval = copy_to_user((unsigned __user *) arg,
218                                                       version, sizeof version)
219                                         ? -EFAULT : 0;
220                         break;
221                 default:
222                         gig_dbg(DEBUG_IF, "%s: arg not supported - 0x%04x",
223                                 __func__, cmd);
224                         retval = -ENOIOCTLCMD;
225                 }
226         }
227
228         mutex_unlock(&cs->mutex);
229
230         return retval;
231 }
232
233 #ifdef CONFIG_COMPAT
234 static long if_compat_ioctl(struct tty_struct *tty,
235                     unsigned int cmd, unsigned long arg)
236 {
237         return if_ioctl(tty, cmd, (unsigned long)compat_ptr(arg));
238 }
239 #endif
240
241 static int if_tiocmget(struct tty_struct *tty)
242 {
243         struct cardstate *cs = tty->driver_data;
244         int retval;
245
246         gig_dbg(DEBUG_IF, "%u: %s()", cs->minor_index, __func__);
247
248         if (mutex_lock_interruptible(&cs->mutex))
249                 return -ERESTARTSYS;
250
251         retval = cs->control_state & (TIOCM_RTS | TIOCM_DTR);
252
253         mutex_unlock(&cs->mutex);
254
255         return retval;
256 }
257
258 static int if_tiocmset(struct tty_struct *tty,
259                        unsigned int set, unsigned int clear)
260 {
261         struct cardstate *cs = tty->driver_data;
262         int retval;
263         unsigned mc;
264
265         gig_dbg(DEBUG_IF, "%u: %s(0x%x, 0x%x)",
266                 cs->minor_index, __func__, set, clear);
267
268         if (mutex_lock_interruptible(&cs->mutex))
269                 return -ERESTARTSYS;
270
271         if (!cs->connected) {
272                 gig_dbg(DEBUG_IF, "not connected");
273                 retval = -ENODEV;
274         } else {
275                 mc = (cs->control_state | set) & ~clear & (TIOCM_RTS | TIOCM_DTR);
276                 retval = cs->ops->set_modem_ctrl(cs, cs->control_state, mc);
277                 cs->control_state = mc;
278         }
279
280         mutex_unlock(&cs->mutex);
281
282         return retval;
283 }
284
285 static int if_write(struct tty_struct *tty, const unsigned char *buf, int count)
286 {
287         struct cardstate *cs = tty->driver_data;
288         struct cmdbuf_t *cb;
289         int retval;
290
291         gig_dbg(DEBUG_IF, "%u: %s()", cs->minor_index, __func__);
292
293         if (mutex_lock_interruptible(&cs->mutex))
294                 return -ERESTARTSYS;
295
296         if (!cs->connected) {
297                 gig_dbg(DEBUG_IF, "not connected");
298                 retval = -ENODEV;
299                 goto done;
300         }
301         if (cs->mstate != MS_LOCKED) {
302                 dev_warn(cs->dev, "can't write to unlocked device\n");
303                 retval = -EBUSY;
304                 goto done;
305         }
306         if (count <= 0) {
307                 /* nothing to do */
308                 retval = 0;
309                 goto done;
310         }
311
312         cb = kmalloc(sizeof(struct cmdbuf_t) + count, GFP_KERNEL);
313         if (!cb) {
314                 dev_err(cs->dev, "%s: out of memory\n", __func__);
315                 retval = -ENOMEM;
316                 goto done;
317         }
318
319         memcpy(cb->buf, buf, count);
320         cb->len = count;
321         cb->offset = 0;
322         cb->next = NULL;
323         cb->wake_tasklet = &cs->if_wake_tasklet;
324         retval = cs->ops->write_cmd(cs, cb);
325 done:
326         mutex_unlock(&cs->mutex);
327         return retval;
328 }
329
330 static int if_write_room(struct tty_struct *tty)
331 {
332         struct cardstate *cs = tty->driver_data;
333         int retval;
334
335         gig_dbg(DEBUG_IF, "%u: %s()", cs->minor_index, __func__);
336
337         if (mutex_lock_interruptible(&cs->mutex))
338                 return -ERESTARTSYS;
339
340         if (!cs->connected) {
341                 gig_dbg(DEBUG_IF, "not connected");
342                 retval = -ENODEV;
343         } else if (cs->mstate != MS_LOCKED) {
344                 dev_warn(cs->dev, "can't write to unlocked device\n");
345                 retval = -EBUSY;
346         } else
347                 retval = cs->ops->write_room(cs);
348
349         mutex_unlock(&cs->mutex);
350
351         return retval;
352 }
353
354 static int if_chars_in_buffer(struct tty_struct *tty)
355 {
356         struct cardstate *cs = tty->driver_data;
357         int retval = 0;
358
359         gig_dbg(DEBUG_IF, "%u: %s()", cs->minor_index, __func__);
360
361         mutex_lock(&cs->mutex);
362
363         if (!cs->connected)
364                 gig_dbg(DEBUG_IF, "not connected");
365         else if (cs->mstate != MS_LOCKED)
366                 dev_warn(cs->dev, "can't write to unlocked device\n");
367         else
368                 retval = cs->ops->chars_in_buffer(cs);
369
370         mutex_unlock(&cs->mutex);
371
372         return retval;
373 }
374
375 static void if_throttle(struct tty_struct *tty)
376 {
377         struct cardstate *cs = tty->driver_data;
378
379         gig_dbg(DEBUG_IF, "%u: %s()", cs->minor_index, __func__);
380
381         mutex_lock(&cs->mutex);
382
383         if (!cs->connected)
384                 gig_dbg(DEBUG_IF, "not connected");     /* nothing to do */
385         else
386                 gig_dbg(DEBUG_IF, "%s: not implemented\n", __func__);
387
388         mutex_unlock(&cs->mutex);
389 }
390
391 static void if_unthrottle(struct tty_struct *tty)
392 {
393         struct cardstate *cs = tty->driver_data;
394
395         gig_dbg(DEBUG_IF, "%u: %s()", cs->minor_index, __func__);
396
397         mutex_lock(&cs->mutex);
398
399         if (!cs->connected)
400                 gig_dbg(DEBUG_IF, "not connected");     /* nothing to do */
401         else
402                 gig_dbg(DEBUG_IF, "%s: not implemented\n", __func__);
403
404         mutex_unlock(&cs->mutex);
405 }
406
407 static void if_set_termios(struct tty_struct *tty, struct ktermios *old)
408 {
409         struct cardstate *cs = tty->driver_data;
410         unsigned int iflag;
411         unsigned int cflag;
412         unsigned int old_cflag;
413         unsigned int control_state, new_state;
414
415         gig_dbg(DEBUG_IF, "%u: %s()", cs->minor_index, __func__);
416
417         mutex_lock(&cs->mutex);
418
419         if (!cs->connected) {
420                 gig_dbg(DEBUG_IF, "not connected");
421                 goto out;
422         }
423
424         iflag = tty->termios.c_iflag;
425         cflag = tty->termios.c_cflag;
426         old_cflag = old ? old->c_cflag : cflag;
427         gig_dbg(DEBUG_IF, "%u: iflag %x cflag %x old %x",
428                 cs->minor_index, iflag, cflag, old_cflag);
429
430         /* get a local copy of the current port settings */
431         control_state = cs->control_state;
432
433         /*
434          * Update baud rate.
435          * Do not attempt to cache old rates and skip settings,
436          * disconnects screw such tricks up completely.
437          * Premature optimization is the root of all evil.
438          */
439
440         /* reassert DTR and (maybe) RTS on transition from B0 */
441         if ((old_cflag & CBAUD) == B0) {
442                 new_state = control_state | TIOCM_DTR;
443                 /* don't set RTS if using hardware flow control */
444                 if (!(old_cflag & CRTSCTS))
445                         new_state |= TIOCM_RTS;
446                 gig_dbg(DEBUG_IF, "%u: from B0 - set DTR%s",
447                         cs->minor_index,
448                         (new_state & TIOCM_RTS) ? " only" : "/RTS");
449                 cs->ops->set_modem_ctrl(cs, control_state, new_state);
450                 control_state = new_state;
451         }
452
453         cs->ops->baud_rate(cs, cflag & CBAUD);
454
455         if ((cflag & CBAUD) == B0) {
456                 /* Drop RTS and DTR */
457                 gig_dbg(DEBUG_IF, "%u: to B0 - drop DTR/RTS", cs->minor_index);
458                 new_state = control_state & ~(TIOCM_DTR | TIOCM_RTS);
459                 cs->ops->set_modem_ctrl(cs, control_state, new_state);
460                 control_state = new_state;
461         }
462
463         /*
464          * Update line control register (LCR)
465          */
466
467         cs->ops->set_line_ctrl(cs, cflag);
468
469         /* save off the modified port settings */
470         cs->control_state = control_state;
471
472 out:
473         mutex_unlock(&cs->mutex);
474 }
475
476 static const struct tty_operations if_ops = {
477         .open =                 if_open,
478         .close =                if_close,
479         .ioctl =                if_ioctl,
480 #ifdef CONFIG_COMPAT
481         .compat_ioctl =         if_compat_ioctl,
482 #endif
483         .write =                if_write,
484         .write_room =           if_write_room,
485         .chars_in_buffer =      if_chars_in_buffer,
486         .set_termios =          if_set_termios,
487         .throttle =             if_throttle,
488         .unthrottle =           if_unthrottle,
489         .tiocmget =             if_tiocmget,
490         .tiocmset =             if_tiocmset,
491 };
492
493
494 /* wakeup tasklet for the write operation */
495 static void if_wake(unsigned long data)
496 {
497         struct cardstate *cs = (struct cardstate *)data;
498
499         tty_port_tty_wakeup(&cs->port);
500 }
501
502 /*** interface to common ***/
503
504 void gigaset_if_init(struct cardstate *cs)
505 {
506         struct gigaset_driver *drv;
507
508         drv = cs->driver;
509         if (!drv->have_tty)
510                 return;
511
512         tasklet_init(&cs->if_wake_tasklet, if_wake, (unsigned long) cs);
513
514         mutex_lock(&cs->mutex);
515         cs->tty_dev = tty_port_register_device(&cs->port, drv->tty,
516                         cs->minor_index, NULL);
517
518         if (!IS_ERR(cs->tty_dev))
519                 dev_set_drvdata(cs->tty_dev, cs);
520         else {
521                 pr_warning("could not register device to the tty subsystem\n");
522                 cs->tty_dev = NULL;
523         }
524         mutex_unlock(&cs->mutex);
525 }
526
527 void gigaset_if_free(struct cardstate *cs)
528 {
529         struct gigaset_driver *drv;
530
531         drv = cs->driver;
532         if (!drv->have_tty)
533                 return;
534
535         tasklet_disable(&cs->if_wake_tasklet);
536         tasklet_kill(&cs->if_wake_tasklet);
537         cs->tty_dev = NULL;
538         tty_unregister_device(drv->tty, cs->minor_index);
539 }
540
541 /**
542  * gigaset_if_receive() - pass a received block of data to the tty device
543  * @cs:         device descriptor structure.
544  * @buffer:     received data.
545  * @len:        number of bytes received.
546  *
547  * Called by asyncdata/isocdata if a block of data received from the
548  * device must be sent to userspace through the ttyG* device.
549  */
550 void gigaset_if_receive(struct cardstate *cs,
551                         unsigned char *buffer, size_t len)
552 {
553         tty_insert_flip_string(&cs->port, buffer, len);
554         tty_flip_buffer_push(&cs->port);
555 }
556 EXPORT_SYMBOL_GPL(gigaset_if_receive);
557
558 /* gigaset_if_initdriver
559  * Initialize tty interface.
560  * parameters:
561  *      drv             Driver
562  *      procname        Name of the driver (e.g. for /proc/tty/drivers)
563  *      devname         Name of the device files (prefix without minor number)
564  */
565 void gigaset_if_initdriver(struct gigaset_driver *drv, const char *procname,
566                            const char *devname)
567 {
568         int ret;
569         struct tty_driver *tty;
570
571         drv->have_tty = 0;
572
573         drv->tty = tty = alloc_tty_driver(drv->minors);
574         if (tty == NULL)
575                 goto enomem;
576
577         tty->type =             TTY_DRIVER_TYPE_SERIAL;
578         tty->subtype =          SERIAL_TYPE_NORMAL;
579         tty->flags =            TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
580
581         tty->driver_name =      procname;
582         tty->name =             devname;
583         tty->minor_start =      drv->minor;
584
585         tty->init_termios          = tty_std_termios;
586         tty->init_termios.c_cflag  = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
587         tty_set_operations(tty, &if_ops);
588
589         ret = tty_register_driver(tty);
590         if (ret < 0) {
591                 pr_err("error %d registering tty driver\n", ret);
592                 goto error;
593         }
594         gig_dbg(DEBUG_IF, "tty driver initialized");
595         drv->have_tty = 1;
596         return;
597
598 enomem:
599         pr_err("out of memory\n");
600 error:
601         if (drv->tty)
602                 put_tty_driver(drv->tty);
603 }
604
605 void gigaset_if_freedriver(struct gigaset_driver *drv)
606 {
607         if (!drv->have_tty)
608                 return;
609
610         drv->have_tty = 0;
611         tty_unregister_driver(drv->tty);
612         put_tty_driver(drv->tty);
613 }