tty: make receive_buf() return the amout of bytes received
[linux-2.6.git] / drivers / isdn / gigaset / ser-gigaset.c
1 /* This is the serial hardware link layer (HLL) for the Gigaset 307x isdn
2  * DECT base (aka Sinus 45 isdn) using the RS232 DECT data module M101,
3  * written as a line discipline.
4  *
5  * =====================================================================
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License as
8  * published by the Free Software Foundation; either version 2 of
9  * the License, or (at your option) any later version.
10  * =====================================================================
11  */
12
13 #include "gigaset.h"
14 #include <linux/module.h>
15 #include <linux/moduleparam.h>
16 #include <linux/platform_device.h>
17 #include <linux/completion.h>
18
19 /* Version Information */
20 #define DRIVER_AUTHOR "Tilman Schmidt"
21 #define DRIVER_DESC "Serial Driver for Gigaset 307x using Siemens M101"
22
23 #define GIGASET_MINORS     1
24 #define GIGASET_MINOR      0
25 #define GIGASET_MODULENAME "ser_gigaset"
26 #define GIGASET_DEVNAME    "ttyGS"
27
28 /* length limit according to Siemens 3070usb-protokoll.doc ch. 2.1 */
29 #define IF_WRITEBUF 264
30
31 MODULE_AUTHOR(DRIVER_AUTHOR);
32 MODULE_DESCRIPTION(DRIVER_DESC);
33 MODULE_LICENSE("GPL");
34 MODULE_ALIAS_LDISC(N_GIGASET_M101);
35
36 static int startmode = SM_ISDN;
37 module_param(startmode, int, S_IRUGO);
38 MODULE_PARM_DESC(startmode, "initial operation mode");
39 static int cidmode = 1;
40 module_param(cidmode, int, S_IRUGO);
41 MODULE_PARM_DESC(cidmode, "stay in CID mode when idle");
42
43 static struct gigaset_driver *driver;
44
45 struct ser_cardstate {
46         struct platform_device  dev;
47         struct tty_struct       *tty;
48         atomic_t                refcnt;
49         struct completion       dead_cmp;
50 };
51
52 static struct platform_driver device_driver = {
53         .driver = {
54                 .name = GIGASET_MODULENAME,
55         },
56 };
57
58 static void flush_send_queue(struct cardstate *);
59
60 /* transmit data from current open skb
61  * result: number of bytes sent or error code < 0
62  */
63 static int write_modem(struct cardstate *cs)
64 {
65         struct tty_struct *tty = cs->hw.ser->tty;
66         struct bc_state *bcs = &cs->bcs[0];     /* only one channel */
67         struct sk_buff *skb = bcs->tx_skb;
68         int sent = -EOPNOTSUPP;
69
70         if (!tty || !tty->driver || !skb)
71                 return -EINVAL;
72
73         if (!skb->len) {
74                 dev_kfree_skb_any(skb);
75                 bcs->tx_skb = NULL;
76                 return -EINVAL;
77         }
78
79         set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
80         if (tty->ops->write)
81                 sent = tty->ops->write(tty, skb->data, skb->len);
82         gig_dbg(DEBUG_OUTPUT, "write_modem: sent %d", sent);
83         if (sent < 0) {
84                 /* error */
85                 flush_send_queue(cs);
86                 return sent;
87         }
88         skb_pull(skb, sent);
89         if (!skb->len) {
90                 /* skb sent completely */
91                 gigaset_skb_sent(bcs, skb);
92
93                 gig_dbg(DEBUG_INTR, "kfree skb (Adr: %lx)!",
94                         (unsigned long) skb);
95                 dev_kfree_skb_any(skb);
96                 bcs->tx_skb = NULL;
97         }
98         return sent;
99 }
100
101 /*
102  * transmit first queued command buffer
103  * result: number of bytes sent or error code < 0
104  */
105 static int send_cb(struct cardstate *cs)
106 {
107         struct tty_struct *tty = cs->hw.ser->tty;
108         struct cmdbuf_t *cb, *tcb;
109         unsigned long flags;
110         int sent = 0;
111
112         if (!tty || !tty->driver)
113                 return -EFAULT;
114
115         cb = cs->cmdbuf;
116         if (!cb)
117                 return 0;       /* nothing to do */
118
119         if (cb->len) {
120                 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
121                 sent = tty->ops->write(tty, cb->buf + cb->offset, cb->len);
122                 if (sent < 0) {
123                         /* error */
124                         gig_dbg(DEBUG_OUTPUT, "send_cb: write error %d", sent);
125                         flush_send_queue(cs);
126                         return sent;
127                 }
128                 cb->offset += sent;
129                 cb->len -= sent;
130                 gig_dbg(DEBUG_OUTPUT, "send_cb: sent %d, left %u, queued %u",
131                         sent, cb->len, cs->cmdbytes);
132         }
133
134         while (cb && !cb->len) {
135                 spin_lock_irqsave(&cs->cmdlock, flags);
136                 cs->cmdbytes -= cs->curlen;
137                 tcb = cb;
138                 cs->cmdbuf = cb = cb->next;
139                 if (cb) {
140                         cb->prev = NULL;
141                         cs->curlen = cb->len;
142                 } else {
143                         cs->lastcmdbuf = NULL;
144                         cs->curlen = 0;
145                 }
146                 spin_unlock_irqrestore(&cs->cmdlock, flags);
147
148                 if (tcb->wake_tasklet)
149                         tasklet_schedule(tcb->wake_tasklet);
150                 kfree(tcb);
151         }
152         return sent;
153 }
154
155 /*
156  * send queue tasklet
157  * If there is already a skb opened, put data to the transfer buffer
158  * by calling "write_modem".
159  * Otherwise take a new skb out of the queue.
160  */
161 static void gigaset_modem_fill(unsigned long data)
162 {
163         struct cardstate *cs = (struct cardstate *) data;
164         struct bc_state *bcs;
165         struct sk_buff *nextskb;
166         int sent = 0;
167
168         if (!cs) {
169                 gig_dbg(DEBUG_OUTPUT, "%s: no cardstate", __func__);
170                 return;
171         }
172         bcs = cs->bcs;
173         if (!bcs) {
174                 gig_dbg(DEBUG_OUTPUT, "%s: no cardstate", __func__);
175                 return;
176         }
177         if (!bcs->tx_skb) {
178                 /* no skb is being sent; send command if any */
179                 sent = send_cb(cs);
180                 gig_dbg(DEBUG_OUTPUT, "%s: send_cb -> %d", __func__, sent);
181                 if (sent)
182                         /* something sent or error */
183                         return;
184
185                 /* no command to send; get skb */
186                 nextskb = skb_dequeue(&bcs->squeue);
187                 if (!nextskb)
188                         /* no skb either, nothing to do */
189                         return;
190                 bcs->tx_skb = nextskb;
191
192                 gig_dbg(DEBUG_INTR, "Dequeued skb (Adr: %lx)",
193                         (unsigned long) bcs->tx_skb);
194         }
195
196         /* send skb */
197         gig_dbg(DEBUG_OUTPUT, "%s: tx_skb", __func__);
198         if (write_modem(cs) < 0)
199                 gig_dbg(DEBUG_OUTPUT, "%s: write_modem failed", __func__);
200 }
201
202 /*
203  * throw away all data queued for sending
204  */
205 static void flush_send_queue(struct cardstate *cs)
206 {
207         struct sk_buff *skb;
208         struct cmdbuf_t *cb;
209         unsigned long flags;
210
211         /* command queue */
212         spin_lock_irqsave(&cs->cmdlock, flags);
213         while ((cb = cs->cmdbuf) != NULL) {
214                 cs->cmdbuf = cb->next;
215                 if (cb->wake_tasklet)
216                         tasklet_schedule(cb->wake_tasklet);
217                 kfree(cb);
218         }
219         cs->cmdbuf = cs->lastcmdbuf = NULL;
220         cs->cmdbytes = cs->curlen = 0;
221         spin_unlock_irqrestore(&cs->cmdlock, flags);
222
223         /* data queue */
224         if (cs->bcs->tx_skb)
225                 dev_kfree_skb_any(cs->bcs->tx_skb);
226         while ((skb = skb_dequeue(&cs->bcs->squeue)) != NULL)
227                 dev_kfree_skb_any(skb);
228 }
229
230
231 /* Gigaset Driver Interface */
232 /* ======================== */
233
234 /*
235  * queue an AT command string for transmission to the Gigaset device
236  * parameters:
237  *      cs              controller state structure
238  *      buf             buffer containing the string to send
239  *      len             number of characters to send
240  *      wake_tasklet    tasklet to run when transmission is complete, or NULL
241  * return value:
242  *      number of bytes queued, or error code < 0
243  */
244 static int gigaset_write_cmd(struct cardstate *cs, struct cmdbuf_t *cb)
245 {
246         unsigned long flags;
247
248         gigaset_dbg_buffer(cs->mstate != MS_LOCKED ?
249                                 DEBUG_TRANSCMD : DEBUG_LOCKCMD,
250                            "CMD Transmit", cb->len, cb->buf);
251
252         spin_lock_irqsave(&cs->cmdlock, flags);
253         cb->prev = cs->lastcmdbuf;
254         if (cs->lastcmdbuf)
255                 cs->lastcmdbuf->next = cb;
256         else {
257                 cs->cmdbuf = cb;
258                 cs->curlen = cb->len;
259         }
260         cs->cmdbytes += cb->len;
261         cs->lastcmdbuf = cb;
262         spin_unlock_irqrestore(&cs->cmdlock, flags);
263
264         spin_lock_irqsave(&cs->lock, flags);
265         if (cs->connected)
266                 tasklet_schedule(&cs->write_tasklet);
267         spin_unlock_irqrestore(&cs->lock, flags);
268         return cb->len;
269 }
270
271 /*
272  * tty_driver.write_room interface routine
273  * return number of characters the driver will accept to be written
274  * parameter:
275  *      controller state structure
276  * return value:
277  *      number of characters
278  */
279 static int gigaset_write_room(struct cardstate *cs)
280 {
281         unsigned bytes;
282
283         bytes = cs->cmdbytes;
284         return bytes < IF_WRITEBUF ? IF_WRITEBUF - bytes : 0;
285 }
286
287 /*
288  * tty_driver.chars_in_buffer interface routine
289  * return number of characters waiting to be sent
290  * parameter:
291  *      controller state structure
292  * return value:
293  *      number of characters
294  */
295 static int gigaset_chars_in_buffer(struct cardstate *cs)
296 {
297         return cs->cmdbytes;
298 }
299
300 /*
301  * implementation of ioctl(GIGASET_BRKCHARS)
302  * parameter:
303  *      controller state structure
304  * return value:
305  *      -EINVAL (unimplemented function)
306  */
307 static int gigaset_brkchars(struct cardstate *cs, const unsigned char buf[6])
308 {
309         /* not implemented */
310         return -EINVAL;
311 }
312
313 /*
314  * Open B channel
315  * Called by "do_action" in ev-layer.c
316  */
317 static int gigaset_init_bchannel(struct bc_state *bcs)
318 {
319         /* nothing to do for M10x */
320         gigaset_bchannel_up(bcs);
321         return 0;
322 }
323
324 /*
325  * Close B channel
326  * Called by "do_action" in ev-layer.c
327  */
328 static int gigaset_close_bchannel(struct bc_state *bcs)
329 {
330         /* nothing to do for M10x */
331         gigaset_bchannel_down(bcs);
332         return 0;
333 }
334
335 /*
336  * Set up B channel structure
337  * This is called by "gigaset_initcs" in common.c
338  */
339 static int gigaset_initbcshw(struct bc_state *bcs)
340 {
341         /* unused */
342         bcs->hw.ser = NULL;
343         return 1;
344 }
345
346 /*
347  * Free B channel structure
348  * Called by "gigaset_freebcs" in common.c
349  */
350 static int gigaset_freebcshw(struct bc_state *bcs)
351 {
352         /* unused */
353         return 1;
354 }
355
356 /*
357  * Reinitialize B channel structure
358  * This is called by "bcs_reinit" in common.c
359  */
360 static void gigaset_reinitbcshw(struct bc_state *bcs)
361 {
362         /* nothing to do for M10x */
363 }
364
365 /*
366  * Free hardware specific device data
367  * This will be called by "gigaset_freecs" in common.c
368  */
369 static void gigaset_freecshw(struct cardstate *cs)
370 {
371         tasklet_kill(&cs->write_tasklet);
372         if (!cs->hw.ser)
373                 return;
374         dev_set_drvdata(&cs->hw.ser->dev.dev, NULL);
375         platform_device_unregister(&cs->hw.ser->dev);
376         kfree(cs->hw.ser);
377         cs->hw.ser = NULL;
378 }
379
380 static void gigaset_device_release(struct device *dev)
381 {
382         struct platform_device *pdev = to_platform_device(dev);
383
384         /* adapted from platform_device_release() in drivers/base/platform.c */
385         kfree(dev->platform_data);
386         kfree(pdev->resource);
387 }
388
389 /*
390  * Set up hardware specific device data
391  * This is called by "gigaset_initcs" in common.c
392  */
393 static int gigaset_initcshw(struct cardstate *cs)
394 {
395         int rc;
396         struct ser_cardstate *scs;
397
398         scs = kzalloc(sizeof(struct ser_cardstate), GFP_KERNEL);
399         if (!scs) {
400                 pr_err("out of memory\n");
401                 return 0;
402         }
403         cs->hw.ser = scs;
404
405         cs->hw.ser->dev.name = GIGASET_MODULENAME;
406         cs->hw.ser->dev.id = cs->minor_index;
407         cs->hw.ser->dev.dev.release = gigaset_device_release;
408         rc = platform_device_register(&cs->hw.ser->dev);
409         if (rc != 0) {
410                 pr_err("error %d registering platform device\n", rc);
411                 kfree(cs->hw.ser);
412                 cs->hw.ser = NULL;
413                 return 0;
414         }
415         dev_set_drvdata(&cs->hw.ser->dev.dev, cs);
416
417         tasklet_init(&cs->write_tasklet,
418                      gigaset_modem_fill, (unsigned long) cs);
419         return 1;
420 }
421
422 /*
423  * set modem control lines
424  * Parameters:
425  *      card state structure
426  *      modem control line state ([TIOCM_DTR]|[TIOCM_RTS])
427  * Called by "gigaset_start" and "gigaset_enterconfigmode" in common.c
428  * and by "if_lock" and "if_termios" in interface.c
429  */
430 static int gigaset_set_modem_ctrl(struct cardstate *cs, unsigned old_state,
431                                   unsigned new_state)
432 {
433         struct tty_struct *tty = cs->hw.ser->tty;
434         unsigned int set, clear;
435
436         if (!tty || !tty->driver || !tty->ops->tiocmset)
437                 return -EINVAL;
438         set = new_state & ~old_state;
439         clear = old_state & ~new_state;
440         if (!set && !clear)
441                 return 0;
442         gig_dbg(DEBUG_IF, "tiocmset set %x clear %x", set, clear);
443         return tty->ops->tiocmset(tty, set, clear);
444 }
445
446 static int gigaset_baud_rate(struct cardstate *cs, unsigned cflag)
447 {
448         return -EINVAL;
449 }
450
451 static int gigaset_set_line_ctrl(struct cardstate *cs, unsigned cflag)
452 {
453         return -EINVAL;
454 }
455
456 static const struct gigaset_ops ops = {
457         gigaset_write_cmd,
458         gigaset_write_room,
459         gigaset_chars_in_buffer,
460         gigaset_brkchars,
461         gigaset_init_bchannel,
462         gigaset_close_bchannel,
463         gigaset_initbcshw,
464         gigaset_freebcshw,
465         gigaset_reinitbcshw,
466         gigaset_initcshw,
467         gigaset_freecshw,
468         gigaset_set_modem_ctrl,
469         gigaset_baud_rate,
470         gigaset_set_line_ctrl,
471         gigaset_m10x_send_skb,  /* asyncdata.c */
472         gigaset_m10x_input,     /* asyncdata.c */
473 };
474
475
476 /* Line Discipline Interface */
477 /* ========================= */
478
479 /* helper functions for cardstate refcounting */
480 static struct cardstate *cs_get(struct tty_struct *tty)
481 {
482         struct cardstate *cs = tty->disc_data;
483
484         if (!cs || !cs->hw.ser) {
485                 gig_dbg(DEBUG_ANY, "%s: no cardstate", __func__);
486                 return NULL;
487         }
488         atomic_inc(&cs->hw.ser->refcnt);
489         return cs;
490 }
491
492 static void cs_put(struct cardstate *cs)
493 {
494         if (atomic_dec_and_test(&cs->hw.ser->refcnt))
495                 complete(&cs->hw.ser->dead_cmp);
496 }
497
498 /*
499  * Called by the tty driver when the line discipline is pushed onto the tty.
500  * Called in process context.
501  */
502 static int
503 gigaset_tty_open(struct tty_struct *tty)
504 {
505         struct cardstate *cs;
506
507         gig_dbg(DEBUG_INIT, "Starting HLL for Gigaset M101");
508
509         pr_info(DRIVER_DESC "\n");
510
511         if (!driver) {
512                 pr_err("%s: no driver structure\n", __func__);
513                 return -ENODEV;
514         }
515
516         /* allocate memory for our device state and initialize it */
517         cs = gigaset_initcs(driver, 1, 1, 0, cidmode, GIGASET_MODULENAME);
518         if (!cs)
519                 goto error;
520
521         cs->dev = &cs->hw.ser->dev.dev;
522         cs->hw.ser->tty = tty;
523         atomic_set(&cs->hw.ser->refcnt, 1);
524         init_completion(&cs->hw.ser->dead_cmp);
525
526         tty->disc_data = cs;
527
528         /* OK.. Initialization of the datastructures and the HW is done.. Now
529          * startup system and notify the LL that we are ready to run
530          */
531         if (startmode == SM_LOCKED)
532                 cs->mstate = MS_LOCKED;
533         if (!gigaset_start(cs)) {
534                 tasklet_kill(&cs->write_tasklet);
535                 goto error;
536         }
537
538         gig_dbg(DEBUG_INIT, "Startup of HLL done");
539         return 0;
540
541 error:
542         gig_dbg(DEBUG_INIT, "Startup of HLL failed");
543         tty->disc_data = NULL;
544         gigaset_freecs(cs);
545         return -ENODEV;
546 }
547
548 /*
549  * Called by the tty driver when the line discipline is removed.
550  * Called from process context.
551  */
552 static void
553 gigaset_tty_close(struct tty_struct *tty)
554 {
555         struct cardstate *cs = tty->disc_data;
556
557         gig_dbg(DEBUG_INIT, "Stopping HLL for Gigaset M101");
558
559         if (!cs) {
560                 gig_dbg(DEBUG_INIT, "%s: no cardstate", __func__);
561                 return;
562         }
563
564         /* prevent other callers from entering ldisc methods */
565         tty->disc_data = NULL;
566
567         if (!cs->hw.ser)
568                 pr_err("%s: no hw cardstate\n", __func__);
569         else {
570                 /* wait for running methods to finish */
571                 if (!atomic_dec_and_test(&cs->hw.ser->refcnt))
572                         wait_for_completion(&cs->hw.ser->dead_cmp);
573         }
574
575         /* stop operations */
576         gigaset_stop(cs);
577         tasklet_kill(&cs->write_tasklet);
578         flush_send_queue(cs);
579         cs->dev = NULL;
580         gigaset_freecs(cs);
581
582         gig_dbg(DEBUG_INIT, "Shutdown of HLL done");
583 }
584
585 /*
586  * Called by the tty driver when the tty line is hung up.
587  * Wait for I/O to driver to complete and unregister ISDN device.
588  * This is already done by the close routine, so just call that.
589  * Called from process context.
590  */
591 static int gigaset_tty_hangup(struct tty_struct *tty)
592 {
593         gigaset_tty_close(tty);
594         return 0;
595 }
596
597 /*
598  * Read on the tty.
599  * Unused, received data goes only to the Gigaset driver.
600  */
601 static ssize_t
602 gigaset_tty_read(struct tty_struct *tty, struct file *file,
603                  unsigned char __user *buf, size_t count)
604 {
605         return -EAGAIN;
606 }
607
608 /*
609  * Write on the tty.
610  * Unused, transmit data comes only from the Gigaset driver.
611  */
612 static ssize_t
613 gigaset_tty_write(struct tty_struct *tty, struct file *file,
614                   const unsigned char *buf, size_t count)
615 {
616         return -EAGAIN;
617 }
618
619 /*
620  * Ioctl on the tty.
621  * Called in process context only.
622  * May be re-entered by multiple ioctl calling threads.
623  */
624 static int
625 gigaset_tty_ioctl(struct tty_struct *tty, struct file *file,
626                   unsigned int cmd, unsigned long arg)
627 {
628         struct cardstate *cs = cs_get(tty);
629         int rc, val;
630         int __user *p = (int __user *)arg;
631
632         if (!cs)
633                 return -ENXIO;
634
635         switch (cmd) {
636
637         case FIONREAD:
638                 /* unused, always return zero */
639                 val = 0;
640                 rc = put_user(val, p);
641                 break;
642
643         case TCFLSH:
644                 /* flush our buffers and the serial port's buffer */
645                 switch (arg) {
646                 case TCIFLUSH:
647                         /* no own input buffer to flush */
648                         break;
649                 case TCIOFLUSH:
650                 case TCOFLUSH:
651                         flush_send_queue(cs);
652                         break;
653                 }
654                 /* Pass through */
655
656         default:
657                 /* pass through to underlying serial device */
658                 rc = n_tty_ioctl_helper(tty, file, cmd, arg);
659                 break;
660         }
661         cs_put(cs);
662         return rc;
663 }
664
665 /*
666  * Called by the tty driver when a block of data has been received.
667  * Will not be re-entered while running but other ldisc functions
668  * may be called in parallel.
669  * Can be called from hard interrupt level as well as soft interrupt
670  * level or mainline.
671  * Parameters:
672  *      tty     tty structure
673  *      buf     buffer containing received characters
674  *      cflags  buffer containing error flags for received characters (ignored)
675  *      count   number of received characters
676  */
677 static unsigned int
678 gigaset_tty_receive(struct tty_struct *tty, const unsigned char *buf,
679                     char *cflags, int count)
680 {
681         struct cardstate *cs = cs_get(tty);
682         unsigned tail, head, n;
683         struct inbuf_t *inbuf;
684
685         if (!cs)
686                 return -ENODEV;
687         inbuf = cs->inbuf;
688         if (!inbuf) {
689                 dev_err(cs->dev, "%s: no inbuf\n", __func__);
690                 cs_put(cs);
691                 return -EINVAL;
692         }
693
694         tail = inbuf->tail;
695         head = inbuf->head;
696         gig_dbg(DEBUG_INTR, "buffer state: %u -> %u, receive %u bytes",
697                 head, tail, count);
698
699         if (head <= tail) {
700                 /* possible buffer wraparound */
701                 n = min_t(unsigned, count, RBUFSIZE - tail);
702                 memcpy(inbuf->data + tail, buf, n);
703                 tail = (tail + n) % RBUFSIZE;
704                 buf += n;
705                 count -= n;
706         }
707
708         if (count > 0) {
709                 /* tail < head and some data left */
710                 n = head - tail - 1;
711                 if (count > n) {
712                         dev_err(cs->dev,
713                                 "inbuf overflow, discarding %d bytes\n",
714                                 count - n);
715                         count = n;
716                 }
717                 memcpy(inbuf->data + tail, buf, count);
718                 tail += count;
719         }
720
721         gig_dbg(DEBUG_INTR, "setting tail to %u", tail);
722         inbuf->tail = tail;
723
724         /* Everything was received .. Push data into handler */
725         gig_dbg(DEBUG_INTR, "%s-->BH", __func__);
726         gigaset_schedule_event(cs);
727         cs_put(cs);
728
729         return count;
730 }
731
732 /*
733  * Called by the tty driver when there's room for more data to send.
734  */
735 static void
736 gigaset_tty_wakeup(struct tty_struct *tty)
737 {
738         struct cardstate *cs = cs_get(tty);
739
740         clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
741         if (!cs)
742                 return;
743         tasklet_schedule(&cs->write_tasklet);
744         cs_put(cs);
745 }
746
747 static struct tty_ldisc_ops gigaset_ldisc = {
748         .owner          = THIS_MODULE,
749         .magic          = TTY_LDISC_MAGIC,
750         .name           = "ser_gigaset",
751         .open           = gigaset_tty_open,
752         .close          = gigaset_tty_close,
753         .hangup         = gigaset_tty_hangup,
754         .read           = gigaset_tty_read,
755         .write          = gigaset_tty_write,
756         .ioctl          = gigaset_tty_ioctl,
757         .receive_buf    = gigaset_tty_receive,
758         .write_wakeup   = gigaset_tty_wakeup,
759 };
760
761
762 /* Initialization / Shutdown */
763 /* ========================= */
764
765 static int __init ser_gigaset_init(void)
766 {
767         int rc;
768
769         gig_dbg(DEBUG_INIT, "%s", __func__);
770         rc = platform_driver_register(&device_driver);
771         if (rc != 0) {
772                 pr_err("error %d registering platform driver\n", rc);
773                 return rc;
774         }
775
776         /* allocate memory for our driver state and initialize it */
777         driver = gigaset_initdriver(GIGASET_MINOR, GIGASET_MINORS,
778                                           GIGASET_MODULENAME, GIGASET_DEVNAME,
779                                           &ops, THIS_MODULE);
780         if (!driver)
781                 goto error;
782
783         rc = tty_register_ldisc(N_GIGASET_M101, &gigaset_ldisc);
784         if (rc != 0) {
785                 pr_err("error %d registering line discipline\n", rc);
786                 goto error;
787         }
788
789         return 0;
790
791 error:
792         if (driver) {
793                 gigaset_freedriver(driver);
794                 driver = NULL;
795         }
796         platform_driver_unregister(&device_driver);
797         return rc;
798 }
799
800 static void __exit ser_gigaset_exit(void)
801 {
802         int rc;
803
804         gig_dbg(DEBUG_INIT, "%s", __func__);
805
806         if (driver) {
807                 gigaset_freedriver(driver);
808                 driver = NULL;
809         }
810
811         rc = tty_unregister_ldisc(N_GIGASET_M101);
812         if (rc != 0)
813                 pr_err("error %d unregistering line discipline\n", rc);
814
815         platform_driver_unregister(&device_driver);
816 }
817
818 module_init(ser_gigaset_init);
819 module_exit(ser_gigaset_exit);