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1/*
2 * n_gsm.c GSM 0710 tty multiplexor
3 * Copyright (c) 2009/10 Intel Corporation
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
17 *
18 * * THIS IS A DEVELOPMENT SNAPSHOT IT IS NOT A FINAL RELEASE *
19 *
20 * TO DO:
21 * Mostly done: ioctls for setting modes/timing
22 * Partly done: hooks so you can pull off frames to non tty devs
23 * Restart DLCI 0 when it closes ?
24 * Test basic encoding
25 * Improve the tx engine
26 * Resolve tx side locking by adding a queue_head and routing
27 * all control traffic via it
28 * General tidy/document
29 * Review the locking/move to refcounts more (mux now moved to an
30 * alloc/free model ready)
31 * Use newest tty open/close port helpers and install hooks
32 * What to do about power functions ?
33 * Termios setting and negotiation
34 * Do we need a 'which mux are you' ioctl to correlate mux and tty sets
35 *
36 */
37
38#include <linux/types.h>
39#include <linux/major.h>
40#include <linux/errno.h>
41#include <linux/signal.h>
42#include <linux/fcntl.h>
43#include <linux/sched.h>
44#include <linux/interrupt.h>
45#include <linux/tty.h>
46#include <linux/ctype.h>
47#include <linux/mm.h>
48#include <linux/string.h>
49#include <linux/slab.h>
50#include <linux/poll.h>
51#include <linux/bitops.h>
52#include <linux/file.h>
53#include <linux/uaccess.h>
54#include <linux/module.h>
55#include <linux/timer.h>
56#include <linux/tty_flip.h>
57#include <linux/tty_driver.h>
58#include <linux/serial.h>
59#include <linux/kfifo.h>
60#include <linux/skbuff.h>
61#include <net/arp.h>
62#include <linux/ip.h>
63#include <linux/netdevice.h>
64#include <linux/etherdevice.h>
65#include <linux/gsmmux.h>
66
67static int debug;
68module_param(debug, int, 0600);
69
70#define T1 (HZ/10)
71#define T2 (HZ/3)
72#define N2 3
73
74/* Use long timers for testing at low speed with debug on */
75#ifdef DEBUG_TIMING
76#define T1 HZ
77#define T2 (2 * HZ)
78#endif
79
80/*
81 * Semi-arbitrary buffer size limits. 0710 is normally run with 32-64 byte
82 * limits so this is plenty
83 */
84#define MAX_MRU 1500
85#define MAX_MTU 1500
86#define GSM_NET_TX_TIMEOUT (HZ*10)
87
88/**
89 * struct gsm_mux_net - network interface
90 * @struct gsm_dlci* dlci
91 * @struct net_device_stats stats;
92 *
93 * Created when net interface is initialized.
94 **/
95struct gsm_mux_net {
96 struct kref ref;
97 struct gsm_dlci *dlci;
98 struct net_device_stats stats;
99};
100
101#define STATS(net) (((struct gsm_mux_net *)netdev_priv(net))->stats)
102
103/*
104 * Each block of data we have queued to go out is in the form of
105 * a gsm_msg which holds everything we need in a link layer independent
106 * format
107 */
108
109struct gsm_msg {
110 struct gsm_msg *next;
111 u8 addr; /* DLCI address + flags */
112 u8 ctrl; /* Control byte + flags */
113 unsigned int len; /* Length of data block (can be zero) */
114 unsigned char *data; /* Points into buffer but not at the start */
115 unsigned char buffer[0];
116};
117
118/*
119 * Each active data link has a gsm_dlci structure associated which ties
120 * the link layer to an optional tty (if the tty side is open). To avoid
121 * complexity right now these are only ever freed up when the mux is
122 * shut down.
123 *
124 * At the moment we don't free DLCI objects until the mux is torn down
125 * this avoid object life time issues but might be worth review later.
126 */
127
128struct gsm_dlci {
129 struct gsm_mux *gsm;
130 int addr;
131 int state;
132#define DLCI_CLOSED 0
133#define DLCI_OPENING 1 /* Sending SABM not seen UA */
134#define DLCI_OPEN 2 /* SABM/UA complete */
135#define DLCI_CLOSING 3 /* Sending DISC not seen UA/DM */
136 struct kref ref; /* freed from port or mux close */
137 struct mutex mutex;
138
139 /* Link layer */
140 spinlock_t lock; /* Protects the internal state */
141 struct timer_list t1; /* Retransmit timer for SABM and UA */
142 int retries;
143 /* Uplink tty if active */
144 struct tty_port port; /* The tty bound to this DLCI if there is one */
145 struct kfifo *fifo; /* Queue fifo for the DLCI */
146 struct kfifo _fifo; /* For new fifo API porting only */
147 int adaption; /* Adaption layer in use */
148 int prev_adaption;
149 u32 modem_rx; /* Our incoming virtual modem lines */
150 u32 modem_tx; /* Our outgoing modem lines */
151 int dead; /* Refuse re-open */
152 /* Flow control */
153 int throttled; /* Private copy of throttle state */
154 int constipated; /* Throttle status for outgoing */
155 /* Packetised I/O */
156 struct sk_buff *skb; /* Frame being sent */
157 struct sk_buff_head skb_list; /* Queued frames */
158 /* Data handling callback */
159 void (*data)(struct gsm_dlci *dlci, u8 *data, int len);
160 void (*prev_data)(struct gsm_dlci *dlci, u8 *data, int len);
161 struct net_device *net; /* network interface, if created */
162};
163
164/* DLCI 0, 62/63 are special or reseved see gsmtty_open */
165
166#define NUM_DLCI 64
167
168/*
169 * DLCI 0 is used to pass control blocks out of band of the data
170 * flow (and with a higher link priority). One command can be outstanding
171 * at a time and we use this structure to manage them. They are created
172 * and destroyed by the user context, and updated by the receive paths
173 * and timers
174 */
175
176struct gsm_control {
177 u8 cmd; /* Command we are issuing */
178 u8 *data; /* Data for the command in case we retransmit */
179 int len; /* Length of block for retransmission */
180 int done; /* Done flag */
181 int error; /* Error if any */
182};
183
184/*
185 * Each GSM mux we have is represented by this structure. If we are
186 * operating as an ldisc then we use this structure as our ldisc
187 * state. We need to sort out lifetimes and locking with respect
188 * to the gsm mux array. For now we don't free DLCI objects that
189 * have been instantiated until the mux itself is terminated.
190 *
191 * To consider further: tty open versus mux shutdown.
192 */
193
194struct gsm_mux {
195 struct tty_struct *tty; /* The tty our ldisc is bound to */
196 spinlock_t lock;
197 unsigned int num;
198 struct kref ref;
199
200 /* Events on the GSM channel */
201 wait_queue_head_t event;
202
203 /* Bits for GSM mode decoding */
204
205 /* Framing Layer */
206 unsigned char *buf;
207 int state;
208#define GSM_SEARCH 0
209#define GSM_START 1
210#define GSM_ADDRESS 2
211#define GSM_CONTROL 3
212#define GSM_LEN 4
213#define GSM_DATA 5
214#define GSM_FCS 6
215#define GSM_OVERRUN 7
216#define GSM_LEN0 8
217#define GSM_LEN1 9
218#define GSM_SSOF 10
219 unsigned int len;
220 unsigned int address;
221 unsigned int count;
222 int escape;
223 int encoding;
224 u8 control;
225 u8 fcs;
226 u8 received_fcs;
227 u8 *txframe; /* TX framing buffer */
228
229 /* Methods for the receiver side */
230 void (*receive)(struct gsm_mux *gsm, u8 ch);
231 void (*error)(struct gsm_mux *gsm, u8 ch, u8 flag);
232 /* And transmit side */
233 int (*output)(struct gsm_mux *mux, u8 *data, int len);
234
235 /* Link Layer */
236 unsigned int mru;
237 unsigned int mtu;
238 int initiator; /* Did we initiate connection */
239 int dead; /* Has the mux been shut down */
240 struct gsm_dlci *dlci[NUM_DLCI];
241 int constipated; /* Asked by remote to shut up */
242
243 spinlock_t tx_lock;
244 unsigned int tx_bytes; /* TX data outstanding */
245#define TX_THRESH_HI 8192
246#define TX_THRESH_LO 2048
247 struct gsm_msg *tx_head; /* Pending data packets */
248 struct gsm_msg *tx_tail;
249
250 /* Control messages */
251 struct timer_list t2_timer; /* Retransmit timer for commands */
252 int cretries; /* Command retry counter */
253 struct gsm_control *pending_cmd;/* Our current pending command */
254 spinlock_t control_lock; /* Protects the pending command */
255
256 /* Configuration */
257 int adaption; /* 1 or 2 supported */
258 u8 ftype; /* UI or UIH */
259 int t1, t2; /* Timers in 1/100th of a sec */
260 int n2; /* Retry count */
261
262 /* Statistics (not currently exposed) */
263 unsigned long bad_fcs;
264 unsigned long malformed;
265 unsigned long io_error;
266 unsigned long bad_size;
267 unsigned long unsupported;
268};
269
270
271/*
272 * Mux objects - needed so that we can translate a tty index into the
273 * relevant mux and DLCI.
274 */
275
276#define MAX_MUX 4 /* 256 minors */
277static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */
278static spinlock_t gsm_mux_lock;
279
280static struct tty_driver *gsm_tty_driver;
281
282/*
283 * This section of the driver logic implements the GSM encodings
284 * both the basic and the 'advanced'. Reliable transport is not
285 * supported.
286 */
287
288#define CR 0x02
289#define EA 0x01
290#define PF 0x10
291
292/* I is special: the rest are ..*/
293#define RR 0x01
294#define UI 0x03
295#define RNR 0x05
296#define REJ 0x09
297#define DM 0x0F
298#define SABM 0x2F
299#define DISC 0x43
300#define UA 0x63
301#define UIH 0xEF
302
303/* Channel commands */
304#define CMD_NSC 0x09
305#define CMD_TEST 0x11
306#define CMD_PSC 0x21
307#define CMD_RLS 0x29
308#define CMD_FCOFF 0x31
309#define CMD_PN 0x41
310#define CMD_RPN 0x49
311#define CMD_FCON 0x51
312#define CMD_CLD 0x61
313#define CMD_SNC 0x69
314#define CMD_MSC 0x71
315
316/* Virtual modem bits */
317#define MDM_FC 0x01
318#define MDM_RTC 0x02
319#define MDM_RTR 0x04
320#define MDM_IC 0x20
321#define MDM_DV 0x40
322
323#define GSM0_SOF 0xF9
324#define GSM1_SOF 0x7E
325#define GSM1_ESCAPE 0x7D
326#define GSM1_ESCAPE_BITS 0x20
327#define XON 0x11
328#define XOFF 0x13
329
330static const struct tty_port_operations gsm_port_ops;
331
332/*
333 * CRC table for GSM 0710
334 */
335
336static const u8 gsm_fcs8[256] = {
337 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75,
338 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B,
339 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69,
340 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67,
341 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D,
342 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43,
343 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51,
344 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F,
345 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05,
346 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B,
347 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19,
348 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17,
349 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D,
350 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33,
351 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21,
352 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F,
353 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95,
354 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B,
355 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89,
356 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87,
357 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD,
358 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3,
359 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1,
360 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF,
361 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5,
362 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB,
363 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9,
364 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7,
365 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD,
366 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3,
367 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1,
368 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF
369};
370
371#define INIT_FCS 0xFF
372#define GOOD_FCS 0xCF
373
374/**
375 * gsm_fcs_add - update FCS
376 * @fcs: Current FCS
377 * @c: Next data
378 *
379 * Update the FCS to include c. Uses the algorithm in the specification
380 * notes.
381 */
382
383static inline u8 gsm_fcs_add(u8 fcs, u8 c)
384{
385 return gsm_fcs8[fcs ^ c];
386}
387
388/**
389 * gsm_fcs_add_block - update FCS for a block
390 * @fcs: Current FCS
391 * @c: buffer of data
392 * @len: length of buffer
393 *
394 * Update the FCS to include c. Uses the algorithm in the specification
395 * notes.
396 */
397
398static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len)
399{
400 while (len--)
401 fcs = gsm_fcs8[fcs ^ *c++];
402 return fcs;
403}
404
405/**
406 * gsm_read_ea - read a byte into an EA
407 * @val: variable holding value
408 * c: byte going into the EA
409 *
410 * Processes one byte of an EA. Updates the passed variable
411 * and returns 1 if the EA is now completely read
412 */
413
414static int gsm_read_ea(unsigned int *val, u8 c)
415{
416 /* Add the next 7 bits into the value */
417 *val <<= 7;
418 *val |= c >> 1;
419 /* Was this the last byte of the EA 1 = yes*/
420 return c & EA;
421}
422
423/**
424 * gsm_encode_modem - encode modem data bits
425 * @dlci: DLCI to encode from
426 *
427 * Returns the correct GSM encoded modem status bits (6 bit field) for
428 * the current status of the DLCI and attached tty object
429 */
430
431static u8 gsm_encode_modem(const struct gsm_dlci *dlci)
432{
433 u8 modembits = 0;
434 /* FC is true flow control not modem bits */
435 if (dlci->throttled)
436 modembits |= MDM_FC;
437 if (dlci->modem_tx & TIOCM_DTR)
438 modembits |= MDM_RTC;
439 if (dlci->modem_tx & TIOCM_RTS)
440 modembits |= MDM_RTR;
441 if (dlci->modem_tx & TIOCM_RI)
442 modembits |= MDM_IC;
443 if (dlci->modem_tx & TIOCM_CD)
444 modembits |= MDM_DV;
445 return modembits;
446}
447
448/**
449 * gsm_print_packet - display a frame for debug
450 * @hdr: header to print before decode
451 * @addr: address EA from the frame
452 * @cr: C/R bit from the frame
453 * @control: control including PF bit
454 * @data: following data bytes
455 * @dlen: length of data
456 *
457 * Displays a packet in human readable format for debugging purposes. The
458 * style is based on amateur radio LAP-B dump display.
459 */
460
461static void gsm_print_packet(const char *hdr, int addr, int cr,
462 u8 control, const u8 *data, int dlen)
463{
464 if (!(debug & 1))
465 return;
466
467 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]);
468
469 switch (control & ~PF) {
470 case SABM:
471 pr_cont("SABM");
472 break;
473 case UA:
474 pr_cont("UA");
475 break;
476 case DISC:
477 pr_cont("DISC");
478 break;
479 case DM:
480 pr_cont("DM");
481 break;
482 case UI:
483 pr_cont("UI");
484 break;
485 case UIH:
486 pr_cont("UIH");
487 break;
488 default:
489 if (!(control & 0x01)) {
490 pr_cont("I N(S)%d N(R)%d",
491 (control & 0x0E) >> 1, (control & 0xE) >> 5);
492 } else switch (control & 0x0F) {
493 case RR:
494 pr_cont("RR(%d)", (control & 0xE0) >> 5);
495 break;
496 case RNR:
497 pr_cont("RNR(%d)", (control & 0xE0) >> 5);
498 break;
499 case REJ:
500 pr_cont("REJ(%d)", (control & 0xE0) >> 5);
501 break;
502 default:
503 pr_cont("[%02X]", control);
504 }
505 }
506
507 if (control & PF)
508 pr_cont("(P)");
509 else
510 pr_cont("(F)");
511
512 if (dlen) {
513 int ct = 0;
514 while (dlen--) {
515 if (ct % 8 == 0) {
516 pr_cont("\n");
517 pr_debug(" ");
518 }
519 pr_cont("%02X ", *data++);
520 ct++;
521 }
522 }
523 pr_cont("\n");
524}
525
526
527/*
528 * Link level transmission side
529 */
530
531/**
532 * gsm_stuff_packet - bytestuff a packet
533 * @ibuf: input
534 * @obuf: output
535 * @len: length of input
536 *
537 * Expand a buffer by bytestuffing it. The worst case size change
538 * is doubling and the caller is responsible for handing out
539 * suitable sized buffers.
540 */
541
542static int gsm_stuff_frame(const u8 *input, u8 *output, int len)
543{
544 int olen = 0;
545 while (len--) {
546 if (*input == GSM1_SOF || *input == GSM1_ESCAPE
547 || *input == XON || *input == XOFF) {
548 *output++ = GSM1_ESCAPE;
549 *output++ = *input++ ^ GSM1_ESCAPE_BITS;
550 olen++;
551 } else
552 *output++ = *input++;
553 olen++;
554 }
555 return olen;
556}
557
558/**
559 * gsm_send - send a control frame
560 * @gsm: our GSM mux
561 * @addr: address for control frame
562 * @cr: command/response bit
563 * @control: control byte including PF bit
564 *
565 * Format up and transmit a control frame. These do not go via the
566 * queueing logic as they should be transmitted ahead of data when
567 * they are needed.
568 *
569 * FIXME: Lock versus data TX path
570 */
571
572static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control)
573{
574 int len;
575 u8 cbuf[10];
576 u8 ibuf[3];
577
578 switch (gsm->encoding) {
579 case 0:
580 cbuf[0] = GSM0_SOF;
581 cbuf[1] = (addr << 2) | (cr << 1) | EA;
582 cbuf[2] = control;
583 cbuf[3] = EA; /* Length of data = 0 */
584 cbuf[4] = 0xFF - gsm_fcs_add_block(INIT_FCS, cbuf + 1, 3);
585 cbuf[5] = GSM0_SOF;
586 len = 6;
587 break;
588 case 1:
589 case 2:
590 /* Control frame + packing (but not frame stuffing) in mode 1 */
591 ibuf[0] = (addr << 2) | (cr << 1) | EA;
592 ibuf[1] = control;
593 ibuf[2] = 0xFF - gsm_fcs_add_block(INIT_FCS, ibuf, 2);
594 /* Stuffing may double the size worst case */
595 len = gsm_stuff_frame(ibuf, cbuf + 1, 3);
596 /* Now add the SOF markers */
597 cbuf[0] = GSM1_SOF;
598 cbuf[len + 1] = GSM1_SOF;
599 /* FIXME: we can omit the lead one in many cases */
600 len += 2;
601 break;
602 default:
603 WARN_ON(1);
604 return;
605 }
606 gsm->output(gsm, cbuf, len);
607 gsm_print_packet("-->", addr, cr, control, NULL, 0);
608}
609
610/**
611 * gsm_response - send a control response
612 * @gsm: our GSM mux
613 * @addr: address for control frame
614 * @control: control byte including PF bit
615 *
616 * Format up and transmit a link level response frame.
617 */
618
619static inline void gsm_response(struct gsm_mux *gsm, int addr, int control)
620{
621 gsm_send(gsm, addr, 0, control);
622}
623
624/**
625 * gsm_command - send a control command
626 * @gsm: our GSM mux
627 * @addr: address for control frame
628 * @control: control byte including PF bit
629 *
630 * Format up and transmit a link level command frame.
631 */
632
633static inline void gsm_command(struct gsm_mux *gsm, int addr, int control)
634{
635 gsm_send(gsm, addr, 1, control);
636}
637
638/* Data transmission */
639
640#define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */
641
642/**
643 * gsm_data_alloc - allocate data frame
644 * @gsm: GSM mux
645 * @addr: DLCI address
646 * @len: length excluding header and FCS
647 * @ctrl: control byte
648 *
649 * Allocate a new data buffer for sending frames with data. Space is left
650 * at the front for header bytes but that is treated as an implementation
651 * detail and not for the high level code to use
652 */
653
654static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
655 u8 ctrl)
656{
657 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN,
658 GFP_ATOMIC);
659 if (m == NULL)
660 return NULL;
661 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */
662 m->len = len;
663 m->addr = addr;
664 m->ctrl = ctrl;
665 m->next = NULL;
666 return m;
667}
668
669/**
670 * gsm_data_kick - poke the queue
671 * @gsm: GSM Mux
672 *
673 * The tty device has called us to indicate that room has appeared in
674 * the transmit queue. Ram more data into the pipe if we have any
675 *
676 * FIXME: lock against link layer control transmissions
677 */
678
679static void gsm_data_kick(struct gsm_mux *gsm)
680{
681 struct gsm_msg *msg = gsm->tx_head;
682 int len;
683 int skip_sof = 0;
684
685 /* FIXME: We need to apply this solely to data messages */
686 if (gsm->constipated)
687 return;
688
689 while (gsm->tx_head != NULL) {
690 msg = gsm->tx_head;
691 if (gsm->encoding != 0) {
692 gsm->txframe[0] = GSM1_SOF;
693 len = gsm_stuff_frame(msg->data,
694 gsm->txframe + 1, msg->len);
695 gsm->txframe[len + 1] = GSM1_SOF;
696 len += 2;
697 } else {
698 gsm->txframe[0] = GSM0_SOF;
699 memcpy(gsm->txframe + 1 , msg->data, msg->len);
700 gsm->txframe[msg->len + 1] = GSM0_SOF;
701 len = msg->len + 2;
702 }
703
704 if (debug & 4)
705 print_hex_dump_bytes("gsm_data_kick: ",
706 DUMP_PREFIX_OFFSET,
707 gsm->txframe, len);
708
709 if (gsm->output(gsm, gsm->txframe + skip_sof,
710 len - skip_sof) < 0)
711 break;
712 /* FIXME: Can eliminate one SOF in many more cases */
713 gsm->tx_head = msg->next;
714 if (gsm->tx_head == NULL)
715 gsm->tx_tail = NULL;
716 gsm->tx_bytes -= msg->len;
717 kfree(msg);
718 /* For a burst of frames skip the extra SOF within the
719 burst */
720 skip_sof = 1;
721 }
722}
723
724/**
725 * __gsm_data_queue - queue a UI or UIH frame
726 * @dlci: DLCI sending the data
727 * @msg: message queued
728 *
729 * Add data to the transmit queue and try and get stuff moving
730 * out of the mux tty if not already doing so. The Caller must hold
731 * the gsm tx lock.
732 */
733
734static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
735{
736 struct gsm_mux *gsm = dlci->gsm;
737 u8 *dp = msg->data;
738 u8 *fcs = dp + msg->len;
739
740 /* Fill in the header */
741 if (gsm->encoding == 0) {
742 if (msg->len < 128)
743 *--dp = (msg->len << 1) | EA;
744 else {
745 *--dp = (msg->len >> 7); /* bits 7 - 15 */
746 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */
747 }
748 }
749
750 *--dp = msg->ctrl;
751 if (gsm->initiator)
752 *--dp = (msg->addr << 2) | 2 | EA;
753 else
754 *--dp = (msg->addr << 2) | EA;
755 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp);
756 /* Ugly protocol layering violation */
757 if (msg->ctrl == UI || msg->ctrl == (UI|PF))
758 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len);
759 *fcs = 0xFF - *fcs;
760
761 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl,
762 msg->data, msg->len);
763
764 /* Move the header back and adjust the length, also allow for the FCS
765 now tacked on the end */
766 msg->len += (msg->data - dp) + 1;
767 msg->data = dp;
768
769 /* Add to the actual output queue */
770 if (gsm->tx_tail)
771 gsm->tx_tail->next = msg;
772 else
773 gsm->tx_head = msg;
774 gsm->tx_tail = msg;
775 gsm->tx_bytes += msg->len;
776 gsm_data_kick(gsm);
777}
778
779/**
780 * gsm_data_queue - queue a UI or UIH frame
781 * @dlci: DLCI sending the data
782 * @msg: message queued
783 *
784 * Add data to the transmit queue and try and get stuff moving
785 * out of the mux tty if not already doing so. Take the
786 * the gsm tx lock and dlci lock.
787 */
788
789static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
790{
791 unsigned long flags;
792 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
793 __gsm_data_queue(dlci, msg);
794 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
795}
796
797/**
798 * gsm_dlci_data_output - try and push data out of a DLCI
799 * @gsm: mux
800 * @dlci: the DLCI to pull data from
801 *
802 * Pull data from a DLCI and send it into the transmit queue if there
803 * is data. Keep to the MRU of the mux. This path handles the usual tty
804 * interface which is a byte stream with optional modem data.
805 *
806 * Caller must hold the tx_lock of the mux.
807 */
808
809static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci)
810{
811 struct gsm_msg *msg;
812 u8 *dp;
813 int len, size;
814 int h = dlci->adaption - 1;
815
816 len = kfifo_len(dlci->fifo);
817 if (len == 0)
818 return 0;
819
820 /* MTU/MRU count only the data bits */
821 if (len > gsm->mtu)
822 len = gsm->mtu;
823
824 size = len + h;
825
826 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
827 /* FIXME: need a timer or something to kick this so it can't
828 get stuck with no work outstanding and no buffer free */
829 if (msg == NULL)
830 return -ENOMEM;
831 dp = msg->data;
832 switch (dlci->adaption) {
833 case 1: /* Unstructured */
834 break;
835 case 2: /* Unstructed with modem bits. Always one byte as we never
836 send inline break data */
837 *dp += gsm_encode_modem(dlci);
838 len--;
839 break;
840 }
841 WARN_ON(kfifo_out_locked(dlci->fifo, dp , len, &dlci->lock) != len);
842 __gsm_data_queue(dlci, msg);
843 /* Bytes of data we used up */
844 return size;
845}
846
847/**
848 * gsm_dlci_data_output_framed - try and push data out of a DLCI
849 * @gsm: mux
850 * @dlci: the DLCI to pull data from
851 *
852 * Pull data from a DLCI and send it into the transmit queue if there
853 * is data. Keep to the MRU of the mux. This path handles framed data
854 * queued as skbuffs to the DLCI.
855 *
856 * Caller must hold the tx_lock of the mux.
857 */
858
859static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
860 struct gsm_dlci *dlci)
861{
862 struct gsm_msg *msg;
863 u8 *dp;
864 int len, size;
865 int last = 0, first = 0;
866 int overhead = 0;
867
868 /* One byte per frame is used for B/F flags */
869 if (dlci->adaption == 4)
870 overhead = 1;
871
872 /* dlci->skb is locked by tx_lock */
873 if (dlci->skb == NULL) {
874 dlci->skb = skb_dequeue(&dlci->skb_list);
875 if (dlci->skb == NULL)
876 return 0;
877 first = 1;
878 }
879 len = dlci->skb->len + overhead;
880
881 /* MTU/MRU count only the data bits */
882 if (len > gsm->mtu) {
883 if (dlci->adaption == 3) {
884 /* Over long frame, bin it */
885 kfree_skb(dlci->skb);
886 dlci->skb = NULL;
887 return 0;
888 }
889 len = gsm->mtu;
890 } else
891 last = 1;
892
893 size = len + overhead;
894 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
895
896 /* FIXME: need a timer or something to kick this so it can't
897 get stuck with no work outstanding and no buffer free */
898 if (msg == NULL)
899 return -ENOMEM;
900 dp = msg->data;
901
902 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */
903 /* Flag byte to carry the start/end info */
904 *dp++ = last << 7 | first << 6 | 1; /* EA */
905 len--;
906 }
907 memcpy(dp, dlci->skb->data, len);
908 skb_pull(dlci->skb, len);
909 __gsm_data_queue(dlci, msg);
910 if (last) {
911 kfree_skb(dlci->skb);
912 dlci->skb = NULL;
913 }
914 return size;
915}
916
917/**
918 * gsm_dlci_data_sweep - look for data to send
919 * @gsm: the GSM mux
920 *
921 * Sweep the GSM mux channels in priority order looking for ones with
922 * data to send. We could do with optimising this scan a bit. We aim
923 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit
924 * TX_THRESH_LO we get called again
925 *
926 * FIXME: We should round robin between groups and in theory you can
927 * renegotiate DLCI priorities with optional stuff. Needs optimising.
928 */
929
930static void gsm_dlci_data_sweep(struct gsm_mux *gsm)
931{
932 int len;
933 /* Priority ordering: We should do priority with RR of the groups */
934 int i = 1;
935
936 while (i < NUM_DLCI) {
937 struct gsm_dlci *dlci;
938
939 if (gsm->tx_bytes > TX_THRESH_HI)
940 break;
941 dlci = gsm->dlci[i];
942 if (dlci == NULL || dlci->constipated) {
943 i++;
944 continue;
945 }
946 if (dlci->adaption < 3 && !dlci->net)
947 len = gsm_dlci_data_output(gsm, dlci);
948 else
949 len = gsm_dlci_data_output_framed(gsm, dlci);
950 if (len < 0)
951 break;
952 /* DLCI empty - try the next */
953 if (len == 0)
954 i++;
955 }
956}
957
958/**
959 * gsm_dlci_data_kick - transmit if possible
960 * @dlci: DLCI to kick
961 *
962 * Transmit data from this DLCI if the queue is empty. We can't rely on
963 * a tty wakeup except when we filled the pipe so we need to fire off
964 * new data ourselves in other cases.
965 */
966
967static void gsm_dlci_data_kick(struct gsm_dlci *dlci)
968{
969 unsigned long flags;
970
971 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
972 /* If we have nothing running then we need to fire up */
973 if (dlci->gsm->tx_bytes == 0) {
974 if (dlci->net)
975 gsm_dlci_data_output_framed(dlci->gsm, dlci);
976 else
977 gsm_dlci_data_output(dlci->gsm, dlci);
978 } else if (dlci->gsm->tx_bytes < TX_THRESH_LO)
979 gsm_dlci_data_sweep(dlci->gsm);
980 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
981}
982
983/*
984 * Control message processing
985 */
986
987
988/**
989 * gsm_control_reply - send a response frame to a control
990 * @gsm: gsm channel
991 * @cmd: the command to use
992 * @data: data to follow encoded info
993 * @dlen: length of data
994 *
995 * Encode up and queue a UI/UIH frame containing our response.
996 */
997
998static void gsm_control_reply(struct gsm_mux *gsm, int cmd, u8 *data,
999 int dlen)
1000{
1001 struct gsm_msg *msg;
1002 msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype);
1003 if (msg == NULL)
1004 return;
1005 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */
1006 msg->data[1] = (dlen << 1) | EA;
1007 memcpy(msg->data + 2, data, dlen);
1008 gsm_data_queue(gsm->dlci[0], msg);
1009}
1010
1011/**
1012 * gsm_process_modem - process received modem status
1013 * @tty: virtual tty bound to the DLCI
1014 * @dlci: DLCI to affect
1015 * @modem: modem bits (full EA)
1016 *
1017 * Used when a modem control message or line state inline in adaption
1018 * layer 2 is processed. Sort out the local modem state and throttles
1019 */
1020
1021static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
1022 u32 modem, int clen)
1023{
1024 int mlines = 0;
1025 u8 brk = 0;
1026
1027 /* The modem status command can either contain one octet (v.24 signals)
1028 or two octets (v.24 signals + break signals). The length field will
1029 either be 2 or 3 respectively. This is specified in section
1030 5.4.6.3.7 of the 27.010 mux spec. */
1031
1032 if (clen == 2)
1033 modem = modem & 0x7f;
1034 else {
1035 brk = modem & 0x7f;
1036 modem = (modem >> 7) & 0x7f;
1037 };
1038
1039 /* Flow control/ready to communicate */
1040 if (modem & MDM_FC) {
1041 /* Need to throttle our output on this device */
1042 dlci->constipated = 1;
1043 }
1044 if (modem & MDM_RTC) {
1045 mlines |= TIOCM_DSR | TIOCM_DTR;
1046 dlci->constipated = 0;
1047 gsm_dlci_data_kick(dlci);
1048 }
1049 /* Map modem bits */
1050 if (modem & MDM_RTR)
1051 mlines |= TIOCM_RTS | TIOCM_CTS;
1052 if (modem & MDM_IC)
1053 mlines |= TIOCM_RI;
1054 if (modem & MDM_DV)
1055 mlines |= TIOCM_CD;
1056
1057 /* Carrier drop -> hangup */
1058 if (tty) {
1059 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD))
1060 if (!(tty->termios->c_cflag & CLOCAL))
1061 tty_hangup(tty);
1062 if (brk & 0x01)
1063 tty_insert_flip_char(tty, 0, TTY_BREAK);
1064 }
1065 dlci->modem_rx = mlines;
1066}
1067
1068/**
1069 * gsm_control_modem - modem status received
1070 * @gsm: GSM channel
1071 * @data: data following command
1072 * @clen: command length
1073 *
1074 * We have received a modem status control message. This is used by
1075 * the GSM mux protocol to pass virtual modem line status and optionally
1076 * to indicate break signals. Unpack it, convert to Linux representation
1077 * and if need be stuff a break message down the tty.
1078 */
1079
1080static void gsm_control_modem(struct gsm_mux *gsm, u8 *data, int clen)
1081{
1082 unsigned int addr = 0;
1083 unsigned int modem = 0;
1084 struct gsm_dlci *dlci;
1085 int len = clen;
1086 u8 *dp = data;
1087 struct tty_struct *tty;
1088
1089 while (gsm_read_ea(&addr, *dp++) == 0) {
1090 len--;
1091 if (len == 0)
1092 return;
1093 }
1094 /* Must be at least one byte following the EA */
1095 len--;
1096 if (len <= 0)
1097 return;
1098
1099 addr >>= 1;
1100 /* Closed port, or invalid ? */
1101 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1102 return;
1103 dlci = gsm->dlci[addr];
1104
1105 while (gsm_read_ea(&modem, *dp++) == 0) {
1106 len--;
1107 if (len == 0)
1108 return;
1109 }
1110 tty = tty_port_tty_get(&dlci->port);
1111 gsm_process_modem(tty, dlci, modem, clen);
1112 if (tty) {
1113 tty_wakeup(tty);
1114 tty_kref_put(tty);
1115 }
1116 gsm_control_reply(gsm, CMD_MSC, data, clen);
1117}
1118
1119/**
1120 * gsm_control_rls - remote line status
1121 * @gsm: GSM channel
1122 * @data: data bytes
1123 * @clen: data length
1124 *
1125 * The modem sends us a two byte message on the control channel whenever
1126 * it wishes to send us an error state from the virtual link. Stuff
1127 * this into the uplink tty if present
1128 */
1129
1130static void gsm_control_rls(struct gsm_mux *gsm, u8 *data, int clen)
1131{
1132 struct tty_struct *tty;
1133 unsigned int addr = 0 ;
1134 u8 bits;
1135 int len = clen;
1136 u8 *dp = data;
1137
1138 while (gsm_read_ea(&addr, *dp++) == 0) {
1139 len--;
1140 if (len == 0)
1141 return;
1142 }
1143 /* Must be at least one byte following ea */
1144 len--;
1145 if (len <= 0)
1146 return;
1147 addr >>= 1;
1148 /* Closed port, or invalid ? */
1149 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1150 return;
1151 /* No error ? */
1152 bits = *dp;
1153 if ((bits & 1) == 0)
1154 return;
1155 /* See if we have an uplink tty */
1156 tty = tty_port_tty_get(&gsm->dlci[addr]->port);
1157
1158 if (tty) {
1159 if (bits & 2)
1160 tty_insert_flip_char(tty, 0, TTY_OVERRUN);
1161 if (bits & 4)
1162 tty_insert_flip_char(tty, 0, TTY_PARITY);
1163 if (bits & 8)
1164 tty_insert_flip_char(tty, 0, TTY_FRAME);
1165 tty_flip_buffer_push(tty);
1166 tty_kref_put(tty);
1167 }
1168 gsm_control_reply(gsm, CMD_RLS, data, clen);
1169}
1170
1171static void gsm_dlci_begin_close(struct gsm_dlci *dlci);
1172
1173/**
1174 * gsm_control_message - DLCI 0 control processing
1175 * @gsm: our GSM mux
1176 * @command: the command EA
1177 * @data: data beyond the command/length EAs
1178 * @clen: length
1179 *
1180 * Input processor for control messages from the other end of the link.
1181 * Processes the incoming request and queues a response frame or an
1182 * NSC response if not supported
1183 */
1184
1185static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
1186 u8 *data, int clen)
1187{
1188 u8 buf[1];
1189 switch (command) {
1190 case CMD_CLD: {
1191 struct gsm_dlci *dlci = gsm->dlci[0];
1192 /* Modem wishes to close down */
1193 if (dlci) {
1194 dlci->dead = 1;
1195 gsm->dead = 1;
1196 gsm_dlci_begin_close(dlci);
1197 }
1198 }
1199 break;
1200 case CMD_TEST:
1201 /* Modem wishes to test, reply with the data */
1202 gsm_control_reply(gsm, CMD_TEST, data, clen);
1203 break;
1204 case CMD_FCON:
1205 /* Modem wants us to STFU */
1206 gsm->constipated = 1;
1207 gsm_control_reply(gsm, CMD_FCON, NULL, 0);
1208 break;
1209 case CMD_FCOFF:
1210 /* Modem can accept data again */
1211 gsm->constipated = 0;
1212 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0);
1213 /* Kick the link in case it is idling */
1214 gsm_data_kick(gsm);
1215 break;
1216 case CMD_MSC:
1217 /* Out of band modem line change indicator for a DLCI */
1218 gsm_control_modem(gsm, data, clen);
1219 break;
1220 case CMD_RLS:
1221 /* Out of band error reception for a DLCI */
1222 gsm_control_rls(gsm, data, clen);
1223 break;
1224 case CMD_PSC:
1225 /* Modem wishes to enter power saving state */
1226 gsm_control_reply(gsm, CMD_PSC, NULL, 0);
1227 break;
1228 /* Optional unsupported commands */
1229 case CMD_PN: /* Parameter negotiation */
1230 case CMD_RPN: /* Remote port negotiation */
1231 case CMD_SNC: /* Service negotiation command */
1232 default:
1233 /* Reply to bad commands with an NSC */
1234 buf[0] = command;
1235 gsm_control_reply(gsm, CMD_NSC, buf, 1);
1236 break;
1237 }
1238}
1239
1240/**
1241 * gsm_control_response - process a response to our control
1242 * @gsm: our GSM mux
1243 * @command: the command (response) EA
1244 * @data: data beyond the command/length EA
1245 * @clen: length
1246 *
1247 * Process a response to an outstanding command. We only allow a single
1248 * control message in flight so this is fairly easy. All the clean up
1249 * is done by the caller, we just update the fields, flag it as done
1250 * and return
1251 */
1252
1253static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
1254 u8 *data, int clen)
1255{
1256 struct gsm_control *ctrl;
1257 unsigned long flags;
1258
1259 spin_lock_irqsave(&gsm->control_lock, flags);
1260
1261 ctrl = gsm->pending_cmd;
1262 /* Does the reply match our command */
1263 command |= 1;
1264 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) {
1265 /* Our command was replied to, kill the retry timer */
1266 del_timer(&gsm->t2_timer);
1267 gsm->pending_cmd = NULL;
1268 /* Rejected by the other end */
1269 if (command == CMD_NSC)
1270 ctrl->error = -EOPNOTSUPP;
1271 ctrl->done = 1;
1272 wake_up(&gsm->event);
1273 }
1274 spin_unlock_irqrestore(&gsm->control_lock, flags);
1275}
1276
1277/**
1278 * gsm_control_transmit - send control packet
1279 * @gsm: gsm mux
1280 * @ctrl: frame to send
1281 *
1282 * Send out a pending control command (called under control lock)
1283 */
1284
1285static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl)
1286{
1287 struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, gsm->ftype);
1288 if (msg == NULL)
1289 return;
1290 msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */
1291 memcpy(msg->data + 1, ctrl->data, ctrl->len);
1292 gsm_data_queue(gsm->dlci[0], msg);
1293}
1294
1295/**
1296 * gsm_control_retransmit - retransmit a control frame
1297 * @data: pointer to our gsm object
1298 *
1299 * Called off the T2 timer expiry in order to retransmit control frames
1300 * that have been lost in the system somewhere. The control_lock protects
1301 * us from colliding with another sender or a receive completion event.
1302 * In that situation the timer may still occur in a small window but
1303 * gsm->pending_cmd will be NULL and we just let the timer expire.
1304 */
1305
1306static void gsm_control_retransmit(unsigned long data)
1307{
1308 struct gsm_mux *gsm = (struct gsm_mux *)data;
1309 struct gsm_control *ctrl;
1310 unsigned long flags;
1311 spin_lock_irqsave(&gsm->control_lock, flags);
1312 ctrl = gsm->pending_cmd;
1313 if (ctrl) {
1314 gsm->cretries--;
1315 if (gsm->cretries == 0) {
1316 gsm->pending_cmd = NULL;
1317 ctrl->error = -ETIMEDOUT;
1318 ctrl->done = 1;
1319 spin_unlock_irqrestore(&gsm->control_lock, flags);
1320 wake_up(&gsm->event);
1321 return;
1322 }
1323 gsm_control_transmit(gsm, ctrl);
1324 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1325 }
1326 spin_unlock_irqrestore(&gsm->control_lock, flags);
1327}
1328
1329/**
1330 * gsm_control_send - send a control frame on DLCI 0
1331 * @gsm: the GSM channel
1332 * @command: command to send including CR bit
1333 * @data: bytes of data (must be kmalloced)
1334 * @len: length of the block to send
1335 *
1336 * Queue and dispatch a control command. Only one command can be
1337 * active at a time. In theory more can be outstanding but the matching
1338 * gets really complicated so for now stick to one outstanding.
1339 */
1340
1341static struct gsm_control *gsm_control_send(struct gsm_mux *gsm,
1342 unsigned int command, u8 *data, int clen)
1343{
1344 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control),
1345 GFP_KERNEL);
1346 unsigned long flags;
1347 if (ctrl == NULL)
1348 return NULL;
1349retry:
1350 wait_event(gsm->event, gsm->pending_cmd == NULL);
1351 spin_lock_irqsave(&gsm->control_lock, flags);
1352 if (gsm->pending_cmd != NULL) {
1353 spin_unlock_irqrestore(&gsm->control_lock, flags);
1354 goto retry;
1355 }
1356 ctrl->cmd = command;
1357 ctrl->data = data;
1358 ctrl->len = clen;
1359 gsm->pending_cmd = ctrl;
1360 gsm->cretries = gsm->n2;
1361 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1362 gsm_control_transmit(gsm, ctrl);
1363 spin_unlock_irqrestore(&gsm->control_lock, flags);
1364 return ctrl;
1365}
1366
1367/**
1368 * gsm_control_wait - wait for a control to finish
1369 * @gsm: GSM mux
1370 * @control: control we are waiting on
1371 *
1372 * Waits for the control to complete or time out. Frees any used
1373 * resources and returns 0 for success, or an error if the remote
1374 * rejected or ignored the request.
1375 */
1376
1377static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
1378{
1379 int err;
1380 wait_event(gsm->event, control->done == 1);
1381 err = control->error;
1382 kfree(control);
1383 return err;
1384}
1385
1386
1387/*
1388 * DLCI level handling: Needs krefs
1389 */
1390
1391/*
1392 * State transitions and timers
1393 */
1394
1395/**
1396 * gsm_dlci_close - a DLCI has closed
1397 * @dlci: DLCI that closed
1398 *
1399 * Perform processing when moving a DLCI into closed state. If there
1400 * is an attached tty this is hung up
1401 */
1402
1403static void gsm_dlci_close(struct gsm_dlci *dlci)
1404{
1405 del_timer(&dlci->t1);
1406 if (debug & 8)
1407 pr_debug("DLCI %d goes closed.\n", dlci->addr);
1408 dlci->state = DLCI_CLOSED;
1409 if (dlci->addr != 0) {
1410 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1411 if (tty) {
1412 tty_hangup(tty);
1413 tty_kref_put(tty);
1414 }
1415 kfifo_reset(dlci->fifo);
1416 } else
1417 dlci->gsm->dead = 1;
1418 wake_up(&dlci->gsm->event);
1419 /* A DLCI 0 close is a MUX termination so we need to kick that
1420 back to userspace somehow */
1421}
1422
1423/**
1424 * gsm_dlci_open - a DLCI has opened
1425 * @dlci: DLCI that opened
1426 *
1427 * Perform processing when moving a DLCI into open state.
1428 */
1429
1430static void gsm_dlci_open(struct gsm_dlci *dlci)
1431{
1432 /* Note that SABM UA .. SABM UA first UA lost can mean that we go
1433 open -> open */
1434 del_timer(&dlci->t1);
1435 /* This will let a tty open continue */
1436 dlci->state = DLCI_OPEN;
1437 if (debug & 8)
1438 pr_debug("DLCI %d goes open.\n", dlci->addr);
1439 wake_up(&dlci->gsm->event);
1440}
1441
1442/**
1443 * gsm_dlci_t1 - T1 timer expiry
1444 * @dlci: DLCI that opened
1445 *
1446 * The T1 timer handles retransmits of control frames (essentially of
1447 * SABM and DISC). We resend the command until the retry count runs out
1448 * in which case an opening port goes back to closed and a closing port
1449 * is simply put into closed state (any further frames from the other
1450 * end will get a DM response)
1451 */
1452
1453static void gsm_dlci_t1(unsigned long data)
1454{
1455 struct gsm_dlci *dlci = (struct gsm_dlci *)data;
1456 struct gsm_mux *gsm = dlci->gsm;
1457
1458 switch (dlci->state) {
1459 case DLCI_OPENING:
1460 dlci->retries--;
1461 if (dlci->retries) {
1462 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1463 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1464 } else
1465 gsm_dlci_close(dlci);
1466 break;
1467 case DLCI_CLOSING:
1468 dlci->retries--;
1469 if (dlci->retries) {
1470 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1471 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1472 } else
1473 gsm_dlci_close(dlci);
1474 break;
1475 }
1476}
1477
1478/**
1479 * gsm_dlci_begin_open - start channel open procedure
1480 * @dlci: DLCI to open
1481 *
1482 * Commence opening a DLCI from the Linux side. We issue SABM messages
1483 * to the modem which should then reply with a UA, at which point we
1484 * will move into open state. Opening is done asynchronously with retry
1485 * running off timers and the responses.
1486 */
1487
1488static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
1489{
1490 struct gsm_mux *gsm = dlci->gsm;
1491 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING)
1492 return;
1493 dlci->retries = gsm->n2;
1494 dlci->state = DLCI_OPENING;
1495 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1496 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1497}
1498
1499/**
1500 * gsm_dlci_begin_close - start channel open procedure
1501 * @dlci: DLCI to open
1502 *
1503 * Commence closing a DLCI from the Linux side. We issue DISC messages
1504 * to the modem which should then reply with a UA, at which point we
1505 * will move into closed state. Closing is done asynchronously with retry
1506 * off timers. We may also receive a DM reply from the other end which
1507 * indicates the channel was already closed.
1508 */
1509
1510static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
1511{
1512 struct gsm_mux *gsm = dlci->gsm;
1513 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
1514 return;
1515 dlci->retries = gsm->n2;
1516 dlci->state = DLCI_CLOSING;
1517 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1518 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1519}
1520
1521/**
1522 * gsm_dlci_data - data arrived
1523 * @dlci: channel
1524 * @data: block of bytes received
1525 * @len: length of received block
1526 *
1527 * A UI or UIH frame has arrived which contains data for a channel
1528 * other than the control channel. If the relevant virtual tty is
1529 * open we shovel the bits down it, if not we drop them.
1530 */
1531
1532static void gsm_dlci_data(struct gsm_dlci *dlci, u8 *data, int clen)
1533{
1534 /* krefs .. */
1535 struct tty_port *port = &dlci->port;
1536 struct tty_struct *tty = tty_port_tty_get(port);
1537 unsigned int modem = 0;
1538 int len = clen;
1539
1540 if (debug & 16)
1541 pr_debug("%d bytes for tty %p\n", len, tty);
1542 if (tty) {
1543 switch (dlci->adaption) {
1544 /* Unsupported types */
1545 /* Packetised interruptible data */
1546 case 4:
1547 break;
1548 /* Packetised uininterruptible voice/data */
1549 case 3:
1550 break;
1551 /* Asynchronous serial with line state in each frame */
1552 case 2:
1553 while (gsm_read_ea(&modem, *data++) == 0) {
1554 len--;
1555 if (len == 0)
1556 return;
1557 }
1558 gsm_process_modem(tty, dlci, modem, clen);
1559 /* Line state will go via DLCI 0 controls only */
1560 case 1:
1561 default:
1562 tty_insert_flip_string(tty, data, len);
1563 tty_flip_buffer_push(tty);
1564 }
1565 tty_kref_put(tty);
1566 }
1567}
1568
1569/**
1570 * gsm_dlci_control - data arrived on control channel
1571 * @dlci: channel
1572 * @data: block of bytes received
1573 * @len: length of received block
1574 *
1575 * A UI or UIH frame has arrived which contains data for DLCI 0 the
1576 * control channel. This should contain a command EA followed by
1577 * control data bytes. The command EA contains a command/response bit
1578 * and we divide up the work accordingly.
1579 */
1580
1581static void gsm_dlci_command(struct gsm_dlci *dlci, u8 *data, int len)
1582{
1583 /* See what command is involved */
1584 unsigned int command = 0;
1585 while (len-- > 0) {
1586 if (gsm_read_ea(&command, *data++) == 1) {
1587 int clen = *data++;
1588 len--;
1589 /* FIXME: this is properly an EA */
1590 clen >>= 1;
1591 /* Malformed command ? */
1592 if (clen > len)
1593 return;
1594 if (command & 1)
1595 gsm_control_message(dlci->gsm, command,
1596 data, clen);
1597 else
1598 gsm_control_response(dlci->gsm, command,
1599 data, clen);
1600 return;
1601 }
1602 }
1603}
1604
1605/*
1606 * Allocate/Free DLCI channels
1607 */
1608
1609/**
1610 * gsm_dlci_alloc - allocate a DLCI
1611 * @gsm: GSM mux
1612 * @addr: address of the DLCI
1613 *
1614 * Allocate and install a new DLCI object into the GSM mux.
1615 *
1616 * FIXME: review locking races
1617 */
1618
1619static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
1620{
1621 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC);
1622 if (dlci == NULL)
1623 return NULL;
1624 spin_lock_init(&dlci->lock);
1625 kref_init(&dlci->ref);
1626 mutex_init(&dlci->mutex);
1627 dlci->fifo = &dlci->_fifo;
1628 if (kfifo_alloc(&dlci->_fifo, 4096, GFP_KERNEL) < 0) {
1629 kfree(dlci);
1630 return NULL;
1631 }
1632
1633 skb_queue_head_init(&dlci->skb_list);
1634 init_timer(&dlci->t1);
1635 dlci->t1.function = gsm_dlci_t1;
1636 dlci->t1.data = (unsigned long)dlci;
1637 tty_port_init(&dlci->port);
1638 dlci->port.ops = &gsm_port_ops;
1639 dlci->gsm = gsm;
1640 dlci->addr = addr;
1641 dlci->adaption = gsm->adaption;
1642 dlci->state = DLCI_CLOSED;
1643 if (addr)
1644 dlci->data = gsm_dlci_data;
1645 else
1646 dlci->data = gsm_dlci_command;
1647 gsm->dlci[addr] = dlci;
1648 return dlci;
1649}
1650
1651/**
1652 * gsm_dlci_free - free DLCI
1653 * @dlci: DLCI to free
1654 *
1655 * Free up a DLCI.
1656 *
1657 * Can sleep.
1658 */
1659static void gsm_dlci_free(struct kref *ref)
1660{
1661 struct gsm_dlci *dlci = container_of(ref, struct gsm_dlci, ref);
1662
1663 del_timer_sync(&dlci->t1);
1664 dlci->gsm->dlci[dlci->addr] = NULL;
1665 kfifo_free(dlci->fifo);
1666 while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
1667 kfree_skb(dlci->skb);
1668 kfree(dlci);
1669}
1670
1671static inline void dlci_get(struct gsm_dlci *dlci)
1672{
1673 kref_get(&dlci->ref);
1674}
1675
1676static inline void dlci_put(struct gsm_dlci *dlci)
1677{
1678 kref_put(&dlci->ref, gsm_dlci_free);
1679}
1680
1681/**
1682 * gsm_dlci_release - release DLCI
1683 * @dlci: DLCI to destroy
1684 *
1685 * Release a DLCI. Actual free is deferred until either
1686 * mux is closed or tty is closed - whichever is last.
1687 *
1688 * Can sleep.
1689 */
1690static void gsm_dlci_release(struct gsm_dlci *dlci)
1691{
1692 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1693 if (tty) {
1694 tty_vhangup(tty);
1695 tty_kref_put(tty);
1696 }
1697 dlci_put(dlci);
1698}
1699
1700/*
1701 * LAPBish link layer logic
1702 */
1703
1704/**
1705 * gsm_queue - a GSM frame is ready to process
1706 * @gsm: pointer to our gsm mux
1707 *
1708 * At this point in time a frame has arrived and been demangled from
1709 * the line encoding. All the differences between the encodings have
1710 * been handled below us and the frame is unpacked into the structures.
1711 * The fcs holds the header FCS but any data FCS must be added here.
1712 */
1713
1714static void gsm_queue(struct gsm_mux *gsm)
1715{
1716 struct gsm_dlci *dlci;
1717 u8 cr;
1718 int address;
1719 /* We have to sneak a look at the packet body to do the FCS.
1720 A somewhat layering violation in the spec */
1721
1722 if ((gsm->control & ~PF) == UI)
1723 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len);
1724 if (gsm->encoding == 0){
1725 /* WARNING: gsm->received_fcs is used for gsm->encoding = 0 only.
1726 In this case it contain the last piece of data
1727 required to generate final CRC */
1728 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs);
1729 }
1730 if (gsm->fcs != GOOD_FCS) {
1731 gsm->bad_fcs++;
1732 if (debug & 4)
1733 pr_debug("BAD FCS %02x\n", gsm->fcs);
1734 return;
1735 }
1736 address = gsm->address >> 1;
1737 if (address >= NUM_DLCI)
1738 goto invalid;
1739
1740 cr = gsm->address & 1; /* C/R bit */
1741
1742 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
1743
1744 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */
1745 dlci = gsm->dlci[address];
1746
1747 switch (gsm->control) {
1748 case SABM|PF:
1749 if (cr == 0)
1750 goto invalid;
1751 if (dlci == NULL)
1752 dlci = gsm_dlci_alloc(gsm, address);
1753 if (dlci == NULL)
1754 return;
1755 if (dlci->dead)
1756 gsm_response(gsm, address, DM);
1757 else {
1758 gsm_response(gsm, address, UA);
1759 gsm_dlci_open(dlci);
1760 }
1761 break;
1762 case DISC|PF:
1763 if (cr == 0)
1764 goto invalid;
1765 if (dlci == NULL || dlci->state == DLCI_CLOSED) {
1766 gsm_response(gsm, address, DM);
1767 return;
1768 }
1769 /* Real close complete */
1770 gsm_response(gsm, address, UA);
1771 gsm_dlci_close(dlci);
1772 break;
1773 case UA:
1774 case UA|PF:
1775 if (cr == 0 || dlci == NULL)
1776 break;
1777 switch (dlci->state) {
1778 case DLCI_CLOSING:
1779 gsm_dlci_close(dlci);
1780 break;
1781 case DLCI_OPENING:
1782 gsm_dlci_open(dlci);
1783 break;
1784 }
1785 break;
1786 case DM: /* DM can be valid unsolicited */
1787 case DM|PF:
1788 if (cr)
1789 goto invalid;
1790 if (dlci == NULL)
1791 return;
1792 gsm_dlci_close(dlci);
1793 break;
1794 case UI:
1795 case UI|PF:
1796 case UIH:
1797 case UIH|PF:
1798#if 0
1799 if (cr)
1800 goto invalid;
1801#endif
1802 if (dlci == NULL || dlci->state != DLCI_OPEN) {
1803 gsm_command(gsm, address, DM|PF);
1804 return;
1805 }
1806 dlci->data(dlci, gsm->buf, gsm->len);
1807 break;
1808 default:
1809 goto invalid;
1810 }
1811 return;
1812invalid:
1813 gsm->malformed++;
1814 return;
1815}
1816
1817
1818/**
1819 * gsm0_receive - perform processing for non-transparency
1820 * @gsm: gsm data for this ldisc instance
1821 * @c: character
1822 *
1823 * Receive bytes in gsm mode 0
1824 */
1825
1826static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
1827{
1828 unsigned int len;
1829
1830 switch (gsm->state) {
1831 case GSM_SEARCH: /* SOF marker */
1832 if (c == GSM0_SOF) {
1833 gsm->state = GSM_ADDRESS;
1834 gsm->address = 0;
1835 gsm->len = 0;
1836 gsm->fcs = INIT_FCS;
1837 }
1838 break;
1839 case GSM_ADDRESS: /* Address EA */
1840 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1841 if (gsm_read_ea(&gsm->address, c))
1842 gsm->state = GSM_CONTROL;
1843 break;
1844 case GSM_CONTROL: /* Control Byte */
1845 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1846 gsm->control = c;
1847 gsm->state = GSM_LEN0;
1848 break;
1849 case GSM_LEN0: /* Length EA */
1850 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1851 if (gsm_read_ea(&gsm->len, c)) {
1852 if (gsm->len > gsm->mru) {
1853 gsm->bad_size++;
1854 gsm->state = GSM_SEARCH;
1855 break;
1856 }
1857 gsm->count = 0;
1858 if (!gsm->len)
1859 gsm->state = GSM_FCS;
1860 else
1861 gsm->state = GSM_DATA;
1862 break;
1863 }
1864 gsm->state = GSM_LEN1;
1865 break;
1866 case GSM_LEN1:
1867 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1868 len = c;
1869 gsm->len |= len << 7;
1870 if (gsm->len > gsm->mru) {
1871 gsm->bad_size++;
1872 gsm->state = GSM_SEARCH;
1873 break;
1874 }
1875 gsm->count = 0;
1876 if (!gsm->len)
1877 gsm->state = GSM_FCS;
1878 else
1879 gsm->state = GSM_DATA;
1880 break;
1881 case GSM_DATA: /* Data */
1882 gsm->buf[gsm->count++] = c;
1883 if (gsm->count == gsm->len)
1884 gsm->state = GSM_FCS;
1885 break;
1886 case GSM_FCS: /* FCS follows the packet */
1887 gsm->received_fcs = c;
1888 gsm_queue(gsm);
1889 gsm->state = GSM_SSOF;
1890 break;
1891 case GSM_SSOF:
1892 if (c == GSM0_SOF) {
1893 gsm->state = GSM_SEARCH;
1894 break;
1895 }
1896 break;
1897 }
1898}
1899
1900/**
1901 * gsm1_receive - perform processing for non-transparency
1902 * @gsm: gsm data for this ldisc instance
1903 * @c: character
1904 *
1905 * Receive bytes in mode 1 (Advanced option)
1906 */
1907
1908static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
1909{
1910 if (c == GSM1_SOF) {
1911 /* EOF is only valid in frame if we have got to the data state
1912 and received at least one byte (the FCS) */
1913 if (gsm->state == GSM_DATA && gsm->count) {
1914 /* Extract the FCS */
1915 gsm->count--;
1916 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
1917 gsm->len = gsm->count;
1918 gsm_queue(gsm);
1919 gsm->state = GSM_START;
1920 return;
1921 }
1922 /* Any partial frame was a runt so go back to start */
1923 if (gsm->state != GSM_START) {
1924 gsm->malformed++;
1925 gsm->state = GSM_START;
1926 }
1927 /* A SOF in GSM_START means we are still reading idling or
1928 framing bytes */
1929 return;
1930 }
1931
1932 if (c == GSM1_ESCAPE) {
1933 gsm->escape = 1;
1934 return;
1935 }
1936
1937 /* Only an unescaped SOF gets us out of GSM search */
1938 if (gsm->state == GSM_SEARCH)
1939 return;
1940
1941 if (gsm->escape) {
1942 c ^= GSM1_ESCAPE_BITS;
1943 gsm->escape = 0;
1944 }
1945 switch (gsm->state) {
1946 case GSM_START: /* First byte after SOF */
1947 gsm->address = 0;
1948 gsm->state = GSM_ADDRESS;
1949 gsm->fcs = INIT_FCS;
1950 /* Drop through */
1951 case GSM_ADDRESS: /* Address continuation */
1952 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1953 if (gsm_read_ea(&gsm->address, c))
1954 gsm->state = GSM_CONTROL;
1955 break;
1956 case GSM_CONTROL: /* Control Byte */
1957 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1958 gsm->control = c;
1959 gsm->count = 0;
1960 gsm->state = GSM_DATA;
1961 break;
1962 case GSM_DATA: /* Data */
1963 if (gsm->count > gsm->mru) { /* Allow one for the FCS */
1964 gsm->state = GSM_OVERRUN;
1965 gsm->bad_size++;
1966 } else
1967 gsm->buf[gsm->count++] = c;
1968 break;
1969 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */
1970 break;
1971 }
1972}
1973
1974/**
1975 * gsm_error - handle tty error
1976 * @gsm: ldisc data
1977 * @data: byte received (may be invalid)
1978 * @flag: error received
1979 *
1980 * Handle an error in the receipt of data for a frame. Currently we just
1981 * go back to hunting for a SOF.
1982 *
1983 * FIXME: better diagnostics ?
1984 */
1985
1986static void gsm_error(struct gsm_mux *gsm,
1987 unsigned char data, unsigned char flag)
1988{
1989 gsm->state = GSM_SEARCH;
1990 gsm->io_error++;
1991}
1992
1993/**
1994 * gsm_cleanup_mux - generic GSM protocol cleanup
1995 * @gsm: our mux
1996 *
1997 * Clean up the bits of the mux which are the same for all framing
1998 * protocols. Remove the mux from the mux table, stop all the timers
1999 * and then shut down each device hanging up the channels as we go.
2000 */
2001
2002void gsm_cleanup_mux(struct gsm_mux *gsm)
2003{
2004 int i;
2005 struct gsm_dlci *dlci = gsm->dlci[0];
2006 struct gsm_msg *txq;
2007
2008 gsm->dead = 1;
2009
2010 spin_lock(&gsm_mux_lock);
2011 for (i = 0; i < MAX_MUX; i++) {
2012 if (gsm_mux[i] == gsm) {
2013 gsm_mux[i] = NULL;
2014 break;
2015 }
2016 }
2017 spin_unlock(&gsm_mux_lock);
2018 WARN_ON(i == MAX_MUX);
2019
2020 del_timer_sync(&gsm->t2_timer);
2021 /* Now we are sure T2 has stopped */
2022 if (dlci) {
2023 dlci->dead = 1;
2024 gsm_dlci_begin_close(dlci);
2025 wait_event_interruptible(gsm->event,
2026 dlci->state == DLCI_CLOSED);
2027 }
2028 /* Free up any link layer users */
2029 for (i = 0; i < NUM_DLCI; i++)
2030 if (gsm->dlci[i])
2031 gsm_dlci_release(gsm->dlci[i]);
2032 /* Now wipe the queues */
2033 for (txq = gsm->tx_head; txq != NULL; txq = gsm->tx_head) {
2034 gsm->tx_head = txq->next;
2035 kfree(txq);
2036 }
2037 gsm->tx_tail = NULL;
2038}
2039EXPORT_SYMBOL_GPL(gsm_cleanup_mux);
2040
2041/**
2042 * gsm_activate_mux - generic GSM setup
2043 * @gsm: our mux
2044 *
2045 * Set up the bits of the mux which are the same for all framing
2046 * protocols. Add the mux to the mux table so it can be opened and
2047 * finally kick off connecting to DLCI 0 on the modem.
2048 */
2049
2050int gsm_activate_mux(struct gsm_mux *gsm)
2051{
2052 struct gsm_dlci *dlci;
2053 int i = 0;
2054
2055 init_timer(&gsm->t2_timer);
2056 gsm->t2_timer.function = gsm_control_retransmit;
2057 gsm->t2_timer.data = (unsigned long)gsm;
2058 init_waitqueue_head(&gsm->event);
2059 spin_lock_init(&gsm->control_lock);
2060 spin_lock_init(&gsm->tx_lock);
2061
2062 if (gsm->encoding == 0)
2063 gsm->receive = gsm0_receive;
2064 else
2065 gsm->receive = gsm1_receive;
2066 gsm->error = gsm_error;
2067
2068 spin_lock(&gsm_mux_lock);
2069 for (i = 0; i < MAX_MUX; i++) {
2070 if (gsm_mux[i] == NULL) {
2071 gsm->num = i;
2072 gsm_mux[i] = gsm;
2073 break;
2074 }
2075 }
2076 spin_unlock(&gsm_mux_lock);
2077 if (i == MAX_MUX)
2078 return -EBUSY;
2079
2080 dlci = gsm_dlci_alloc(gsm, 0);
2081 if (dlci == NULL)
2082 return -ENOMEM;
2083 gsm->dead = 0; /* Tty opens are now permissible */
2084 return 0;
2085}
2086EXPORT_SYMBOL_GPL(gsm_activate_mux);
2087
2088/**
2089 * gsm_free_mux - free up a mux
2090 * @mux: mux to free
2091 *
2092 * Dispose of allocated resources for a dead mux
2093 */
2094void gsm_free_mux(struct gsm_mux *gsm)
2095{
2096 kfree(gsm->txframe);
2097 kfree(gsm->buf);
2098 kfree(gsm);
2099}
2100EXPORT_SYMBOL_GPL(gsm_free_mux);
2101
2102/**
2103 * gsm_free_muxr - free up a mux
2104 * @mux: mux to free
2105 *
2106 * Dispose of allocated resources for a dead mux
2107 */
2108static void gsm_free_muxr(struct kref *ref)
2109{
2110 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref);
2111 gsm_free_mux(gsm);
2112}
2113
2114static inline void mux_get(struct gsm_mux *gsm)
2115{
2116 kref_get(&gsm->ref);
2117}
2118
2119static inline void mux_put(struct gsm_mux *gsm)
2120{
2121 kref_put(&gsm->ref, gsm_free_muxr);
2122}
2123
2124/**
2125 * gsm_alloc_mux - allocate a mux
2126 *
2127 * Creates a new mux ready for activation.
2128 */
2129
2130struct gsm_mux *gsm_alloc_mux(void)
2131{
2132 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
2133 if (gsm == NULL)
2134 return NULL;
2135 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL);
2136 if (gsm->buf == NULL) {
2137 kfree(gsm);
2138 return NULL;
2139 }
2140 gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL);
2141 if (gsm->txframe == NULL) {
2142 kfree(gsm->buf);
2143 kfree(gsm);
2144 return NULL;
2145 }
2146 spin_lock_init(&gsm->lock);
2147 kref_init(&gsm->ref);
2148
2149 gsm->t1 = T1;
2150 gsm->t2 = T2;
2151 gsm->n2 = N2;
2152 gsm->ftype = UIH;
2153 gsm->adaption = 1;
2154 gsm->encoding = 1;
2155 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
2156 gsm->mtu = 64;
2157 gsm->dead = 1; /* Avoid early tty opens */
2158
2159 return gsm;
2160}
2161EXPORT_SYMBOL_GPL(gsm_alloc_mux);
2162
2163/**
2164 * gsmld_output - write to link
2165 * @gsm: our mux
2166 * @data: bytes to output
2167 * @len: size
2168 *
2169 * Write a block of data from the GSM mux to the data channel. This
2170 * will eventually be serialized from above but at the moment isn't.
2171 */
2172
2173static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
2174{
2175 if (tty_write_room(gsm->tty) < len) {
2176 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
2177 return -ENOSPC;
2178 }
2179 if (debug & 4)
2180 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET,
2181 data, len);
2182 gsm->tty->ops->write(gsm->tty, data, len);
2183 return len;
2184}
2185
2186/**
2187 * gsmld_attach_gsm - mode set up
2188 * @tty: our tty structure
2189 * @gsm: our mux
2190 *
2191 * Set up the MUX for basic mode and commence connecting to the
2192 * modem. Currently called from the line discipline set up but
2193 * will need moving to an ioctl path.
2194 */
2195
2196static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2197{
2198 int ret, i;
2199 int base = gsm->num << 6; /* Base for this MUX */
2200
2201 gsm->tty = tty_kref_get(tty);
2202 gsm->output = gsmld_output;
2203 ret = gsm_activate_mux(gsm);
2204 if (ret != 0)
2205 tty_kref_put(gsm->tty);
2206 else {
2207 /* Don't register device 0 - this is the control channel and not
2208 a usable tty interface */
2209 for (i = 1; i < NUM_DLCI; i++)
2210 tty_register_device(gsm_tty_driver, base + i, NULL);
2211 }
2212 return ret;
2213}
2214
2215
2216/**
2217 * gsmld_detach_gsm - stop doing 0710 mux
2218 * @tty: tty attached to the mux
2219 * @gsm: mux
2220 *
2221 * Shutdown and then clean up the resources used by the line discipline
2222 */
2223
2224static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2225{
2226 int i;
2227 int base = gsm->num << 6; /* Base for this MUX */
2228
2229 WARN_ON(tty != gsm->tty);
2230 for (i = 1; i < NUM_DLCI; i++)
2231 tty_unregister_device(gsm_tty_driver, base + i);
2232 gsm_cleanup_mux(gsm);
2233 tty_kref_put(gsm->tty);
2234 gsm->tty = NULL;
2235}
2236
2237static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
2238 char *fp, int count)
2239{
2240 struct gsm_mux *gsm = tty->disc_data;
2241 const unsigned char *dp;
2242 char *f;
2243 int i;
2244 char buf[64];
2245 char flags;
2246
2247 if (debug & 4)
2248 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET,
2249 cp, count);
2250
2251 for (i = count, dp = cp, f = fp; i; i--, dp++) {
2252 flags = *f++;
2253 switch (flags) {
2254 case TTY_NORMAL:
2255 gsm->receive(gsm, *dp);
2256 break;
2257 case TTY_OVERRUN:
2258 case TTY_BREAK:
2259 case TTY_PARITY:
2260 case TTY_FRAME:
2261 gsm->error(gsm, *dp, flags);
2262 break;
2263 default:
2264 WARN_ONCE("%s: unknown flag %d\n",
2265 tty_name(tty, buf), flags);
2266 break;
2267 }
2268 }
2269 /* FASYNC if needed ? */
2270 /* If clogged call tty_throttle(tty); */
2271}
2272
2273/**
2274 * gsmld_chars_in_buffer - report available bytes
2275 * @tty: tty device
2276 *
2277 * Report the number of characters buffered to be delivered to user
2278 * at this instant in time.
2279 *
2280 * Locking: gsm lock
2281 */
2282
2283static ssize_t gsmld_chars_in_buffer(struct tty_struct *tty)
2284{
2285 return 0;
2286}
2287
2288/**
2289 * gsmld_flush_buffer - clean input queue
2290 * @tty: terminal device
2291 *
2292 * Flush the input buffer. Called when the line discipline is
2293 * being closed, when the tty layer wants the buffer flushed (eg
2294 * at hangup).
2295 */
2296
2297static void gsmld_flush_buffer(struct tty_struct *tty)
2298{
2299}
2300
2301/**
2302 * gsmld_close - close the ldisc for this tty
2303 * @tty: device
2304 *
2305 * Called from the terminal layer when this line discipline is
2306 * being shut down, either because of a close or becsuse of a
2307 * discipline change. The function will not be called while other
2308 * ldisc methods are in progress.
2309 */
2310
2311static void gsmld_close(struct tty_struct *tty)
2312{
2313 struct gsm_mux *gsm = tty->disc_data;
2314
2315 gsmld_detach_gsm(tty, gsm);
2316
2317 gsmld_flush_buffer(tty);
2318 /* Do other clean up here */
2319 mux_put(gsm);
2320}
2321
2322/**
2323 * gsmld_open - open an ldisc
2324 * @tty: terminal to open
2325 *
2326 * Called when this line discipline is being attached to the
2327 * terminal device. Can sleep. Called serialized so that no
2328 * other events will occur in parallel. No further open will occur
2329 * until a close.
2330 */
2331
2332static int gsmld_open(struct tty_struct *tty)
2333{
2334 struct gsm_mux *gsm;
2335
2336 if (tty->ops->write == NULL)
2337 return -EINVAL;
2338
2339 /* Attach our ldisc data */
2340 gsm = gsm_alloc_mux();
2341 if (gsm == NULL)
2342 return -ENOMEM;
2343
2344 tty->disc_data = gsm;
2345 tty->receive_room = 65536;
2346
2347 /* Attach the initial passive connection */
2348 gsm->encoding = 1;
2349 return gsmld_attach_gsm(tty, gsm);
2350}
2351
2352/**
2353 * gsmld_write_wakeup - asynchronous I/O notifier
2354 * @tty: tty device
2355 *
2356 * Required for the ptys, serial driver etc. since processes
2357 * that attach themselves to the master and rely on ASYNC
2358 * IO must be woken up
2359 */
2360
2361static void gsmld_write_wakeup(struct tty_struct *tty)
2362{
2363 struct gsm_mux *gsm = tty->disc_data;
2364 unsigned long flags;
2365
2366 /* Queue poll */
2367 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2368 gsm_data_kick(gsm);
2369 if (gsm->tx_bytes < TX_THRESH_LO) {
2370 spin_lock_irqsave(&gsm->tx_lock, flags);
2371 gsm_dlci_data_sweep(gsm);
2372 spin_unlock_irqrestore(&gsm->tx_lock, flags);
2373 }
2374}
2375
2376/**
2377 * gsmld_read - read function for tty
2378 * @tty: tty device
2379 * @file: file object
2380 * @buf: userspace buffer pointer
2381 * @nr: size of I/O
2382 *
2383 * Perform reads for the line discipline. We are guaranteed that the
2384 * line discipline will not be closed under us but we may get multiple
2385 * parallel readers and must handle this ourselves. We may also get
2386 * a hangup. Always called in user context, may sleep.
2387 *
2388 * This code must be sure never to sleep through a hangup.
2389 */
2390
2391static ssize_t gsmld_read(struct tty_struct *tty, struct file *file,
2392 unsigned char __user *buf, size_t nr)
2393{
2394 return -EOPNOTSUPP;
2395}
2396
2397/**
2398 * gsmld_write - write function for tty
2399 * @tty: tty device
2400 * @file: file object
2401 * @buf: userspace buffer pointer
2402 * @nr: size of I/O
2403 *
2404 * Called when the owner of the device wants to send a frame
2405 * itself (or some other control data). The data is transferred
2406 * as-is and must be properly framed and checksummed as appropriate
2407 * by userspace. Frames are either sent whole or not at all as this
2408 * avoids pain user side.
2409 */
2410
2411static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
2412 const unsigned char *buf, size_t nr)
2413{
2414 int space = tty_write_room(tty);
2415 if (space >= nr)
2416 return tty->ops->write(tty, buf, nr);
2417 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2418 return -ENOBUFS;
2419}
2420
2421/**
2422 * gsmld_poll - poll method for N_GSM0710
2423 * @tty: terminal device
2424 * @file: file accessing it
2425 * @wait: poll table
2426 *
2427 * Called when the line discipline is asked to poll() for data or
2428 * for special events. This code is not serialized with respect to
2429 * other events save open/close.
2430 *
2431 * This code must be sure never to sleep through a hangup.
2432 * Called without the kernel lock held - fine
2433 */
2434
2435static unsigned int gsmld_poll(struct tty_struct *tty, struct file *file,
2436 poll_table *wait)
2437{
2438 unsigned int mask = 0;
2439 struct gsm_mux *gsm = tty->disc_data;
2440
2441 poll_wait(file, &tty->read_wait, wait);
2442 poll_wait(file, &tty->write_wait, wait);
2443 if (tty_hung_up_p(file))
2444 mask |= POLLHUP;
2445 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
2446 mask |= POLLOUT | POLLWRNORM;
2447 if (gsm->dead)
2448 mask |= POLLHUP;
2449 return mask;
2450}
2451
2452static int gsmld_config(struct tty_struct *tty, struct gsm_mux *gsm,
2453 struct gsm_config *c)
2454{
2455 int need_close = 0;
2456 int need_restart = 0;
2457
2458 /* Stuff we don't support yet - UI or I frame transport, windowing */
2459 if ((c->adaption != 1 && c->adaption != 2) || c->k)
2460 return -EOPNOTSUPP;
2461 /* Check the MRU/MTU range looks sane */
2462 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8)
2463 return -EINVAL;
2464 if (c->n2 < 3)
2465 return -EINVAL;
2466 if (c->encapsulation > 1) /* Basic, advanced, no I */
2467 return -EINVAL;
2468 if (c->initiator > 1)
2469 return -EINVAL;
2470 if (c->i == 0 || c->i > 2) /* UIH and UI only */
2471 return -EINVAL;
2472 /*
2473 * See what is needed for reconfiguration
2474 */
2475
2476 /* Timing fields */
2477 if (c->t1 != 0 && c->t1 != gsm->t1)
2478 need_restart = 1;
2479 if (c->t2 != 0 && c->t2 != gsm->t2)
2480 need_restart = 1;
2481 if (c->encapsulation != gsm->encoding)
2482 need_restart = 1;
2483 if (c->adaption != gsm->adaption)
2484 need_restart = 1;
2485 /* Requires care */
2486 if (c->initiator != gsm->initiator)
2487 need_close = 1;
2488 if (c->mru != gsm->mru)
2489 need_restart = 1;
2490 if (c->mtu != gsm->mtu)
2491 need_restart = 1;
2492
2493 /*
2494 * Close down what is needed, restart and initiate the new
2495 * configuration
2496 */
2497
2498 if (need_close || need_restart) {
2499 gsm_dlci_begin_close(gsm->dlci[0]);
2500 /* This will timeout if the link is down due to N2 expiring */
2501 wait_event_interruptible(gsm->event,
2502 gsm->dlci[0]->state == DLCI_CLOSED);
2503 if (signal_pending(current))
2504 return -EINTR;
2505 }
2506 if (need_restart)
2507 gsm_cleanup_mux(gsm);
2508
2509 gsm->initiator = c->initiator;
2510 gsm->mru = c->mru;
2511 gsm->mtu = c->mtu;
2512 gsm->encoding = c->encapsulation;
2513 gsm->adaption = c->adaption;
2514 gsm->n2 = c->n2;
2515
2516 if (c->i == 1)
2517 gsm->ftype = UIH;
2518 else if (c->i == 2)
2519 gsm->ftype = UI;
2520
2521 if (c->t1)
2522 gsm->t1 = c->t1;
2523 if (c->t2)
2524 gsm->t2 = c->t2;
2525
2526 /* FIXME: We need to separate activation/deactivation from adding
2527 and removing from the mux array */
2528 if (need_restart)
2529 gsm_activate_mux(gsm);
2530 if (gsm->initiator && need_close)
2531 gsm_dlci_begin_open(gsm->dlci[0]);
2532 return 0;
2533}
2534
2535static int gsmld_ioctl(struct tty_struct *tty, struct file *file,
2536 unsigned int cmd, unsigned long arg)
2537{
2538 struct gsm_config c;
2539 struct gsm_mux *gsm = tty->disc_data;
2540
2541 switch (cmd) {
2542 case GSMIOC_GETCONF:
2543 memset(&c, 0, sizeof(c));
2544 c.adaption = gsm->adaption;
2545 c.encapsulation = gsm->encoding;
2546 c.initiator = gsm->initiator;
2547 c.t1 = gsm->t1;
2548 c.t2 = gsm->t2;
2549 c.t3 = 0; /* Not supported */
2550 c.n2 = gsm->n2;
2551 if (gsm->ftype == UIH)
2552 c.i = 1;
2553 else
2554 c.i = 2;
2555 pr_debug("Ftype %d i %d\n", gsm->ftype, c.i);
2556 c.mru = gsm->mru;
2557 c.mtu = gsm->mtu;
2558 c.k = 0;
2559 if (copy_to_user((void *)arg, &c, sizeof(c)))
2560 return -EFAULT;
2561 return 0;
2562 case GSMIOC_SETCONF:
2563 if (copy_from_user(&c, (void *)arg, sizeof(c)))
2564 return -EFAULT;
2565 return gsmld_config(tty, gsm, &c);
2566 default:
2567 return n_tty_ioctl_helper(tty, file, cmd, arg);
2568 }
2569}
2570
2571/*
2572 * Network interface
2573 *
2574 */
2575
2576static int gsm_mux_net_open(struct net_device *net)
2577{
2578 pr_debug("%s called\n", __func__);
2579 netif_start_queue(net);
2580 return 0;
2581}
2582
2583static int gsm_mux_net_close(struct net_device *net)
2584{
2585 netif_stop_queue(net);
2586 return 0;
2587}
2588
2589static struct net_device_stats *gsm_mux_net_get_stats(struct net_device *net)
2590{
2591 return &((struct gsm_mux_net *)netdev_priv(net))->stats;
2592}
2593static void dlci_net_free(struct gsm_dlci *dlci)
2594{
2595 if (!dlci->net) {
2596 WARN_ON(1);
2597 return;
2598 }
2599 dlci->adaption = dlci->prev_adaption;
2600 dlci->data = dlci->prev_data;
2601 free_netdev(dlci->net);
2602 dlci->net = NULL;
2603}
2604static void net_free(struct kref *ref)
2605{
2606 struct gsm_mux_net *mux_net;
2607 struct gsm_dlci *dlci;
2608
2609 mux_net = container_of(ref, struct gsm_mux_net, ref);
2610 dlci = mux_net->dlci;
2611
2612 if (dlci->net) {
2613 unregister_netdev(dlci->net);
2614 dlci_net_free(dlci);
2615 }
2616}
2617
2618static inline void muxnet_get(struct gsm_mux_net *mux_net)
2619{
2620 kref_get(&mux_net->ref);
2621}
2622
2623static inline void muxnet_put(struct gsm_mux_net *mux_net)
2624{
2625 kref_put(&mux_net->ref, net_free);
2626}
2627
2628static int gsm_mux_net_start_xmit(struct sk_buff *skb,
2629 struct net_device *net)
2630{
2631 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
2632 struct gsm_dlci *dlci = mux_net->dlci;
2633 muxnet_get(mux_net);
2634
2635 skb_queue_head(&dlci->skb_list, skb);
2636 STATS(net).tx_packets++;
2637 STATS(net).tx_bytes += skb->len;
2638 gsm_dlci_data_kick(dlci);
2639 /* And tell the kernel when the last transmit started. */
2640 net->trans_start = jiffies;
2641 muxnet_put(mux_net);
2642 return NETDEV_TX_OK;
2643}
2644
2645/* called when a packet did not ack after watchdogtimeout */
2646static void gsm_mux_net_tx_timeout(struct net_device *net)
2647{
2648 /* Tell syslog we are hosed. */
2649 dev_dbg(&net->dev, "Tx timed out.\n");
2650
2651 /* Update statistics */
2652 STATS(net).tx_errors++;
2653}
2654
2655static void gsm_mux_rx_netchar(struct gsm_dlci *dlci,
2656 unsigned char *in_buf, int size)
2657{
2658 struct net_device *net = dlci->net;
2659 struct sk_buff *skb;
2660 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
2661 muxnet_get(mux_net);
2662
2663 /* Allocate an sk_buff */
2664 skb = dev_alloc_skb(size + NET_IP_ALIGN);
2665 if (!skb) {
2666 /* We got no receive buffer. */
2667 STATS(net).rx_dropped++;
2668 muxnet_put(mux_net);
2669 return;
2670 }
2671 skb_reserve(skb, NET_IP_ALIGN);
2672 memcpy(skb_put(skb, size), in_buf, size);
2673
2674 skb->dev = net;
2675 skb->protocol = __constant_htons(ETH_P_IP);
2676
2677 /* Ship it off to the kernel */
2678 netif_rx(skb);
2679
2680 /* update out statistics */
2681 STATS(net).rx_packets++;
2682 STATS(net).rx_bytes += size;
2683 muxnet_put(mux_net);
2684 return;
2685}
2686
2687int gsm_change_mtu(struct net_device *net, int new_mtu)
2688{
2689 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
2690 if ((new_mtu < 8) || (new_mtu > mux_net->dlci->gsm->mtu))
2691 return -EINVAL;
2692 net->mtu = new_mtu;
2693 return 0;
2694}
2695
2696static void gsm_mux_net_init(struct net_device *net)
2697{
2698 static const struct net_device_ops gsm_netdev_ops = {
2699 .ndo_open = gsm_mux_net_open,
2700 .ndo_stop = gsm_mux_net_close,
2701 .ndo_start_xmit = gsm_mux_net_start_xmit,
2702 .ndo_tx_timeout = gsm_mux_net_tx_timeout,
2703 .ndo_get_stats = gsm_mux_net_get_stats,
2704 .ndo_change_mtu = gsm_change_mtu,
2705 };
2706
2707 net->netdev_ops = &gsm_netdev_ops;
2708
2709 /* fill in the other fields */
2710 net->watchdog_timeo = GSM_NET_TX_TIMEOUT;
2711 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
2712 net->type = ARPHRD_NONE;
2713 net->tx_queue_len = 10;
2714}
2715
2716
2717/* caller holds the dlci mutex */
2718static void gsm_destroy_network(struct gsm_dlci *dlci)
2719{
2720 struct gsm_mux_net *mux_net;
2721
2722 pr_debug("destroy network interface");
2723 if (!dlci->net)
2724 return;
2725 mux_net = (struct gsm_mux_net *)netdev_priv(dlci->net);
2726 muxnet_put(mux_net);
2727}
2728
2729
2730/* caller holds the dlci mutex */
2731static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
2732{
2733 char *netname;
2734 int retval = 0;
2735 struct net_device *net;
2736 struct gsm_mux_net *mux_net;
2737
2738 if (!capable(CAP_NET_ADMIN))
2739 return -EPERM;
2740
2741 /* Already in a non tty mode */
2742 if (dlci->adaption > 2)
2743 return -EBUSY;
2744
2745 if (nc->protocol != htons(ETH_P_IP))
2746 return -EPROTONOSUPPORT;
2747
2748 if (nc->adaption != 3 && nc->adaption != 4)
2749 return -EPROTONOSUPPORT;
2750
2751 pr_debug("create network interface");
2752
2753 netname = "gsm%d";
2754 if (nc->if_name[0] != '\0')
2755 netname = nc->if_name;
2756 net = alloc_netdev(sizeof(struct gsm_mux_net),
2757 netname,
2758 gsm_mux_net_init);
2759 if (!net) {
2760 pr_err("alloc_netdev failed");
2761 return -ENOMEM;
2762 }
2763 net->mtu = dlci->gsm->mtu;
2764 mux_net = (struct gsm_mux_net *)netdev_priv(net);
2765 mux_net->dlci = dlci;
2766 kref_init(&mux_net->ref);
2767 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */
2768
2769 /* reconfigure dlci for network */
2770 dlci->prev_adaption = dlci->adaption;
2771 dlci->prev_data = dlci->data;
2772 dlci->adaption = nc->adaption;
2773 dlci->data = gsm_mux_rx_netchar;
2774 dlci->net = net;
2775
2776 pr_debug("register netdev");
2777 retval = register_netdev(net);
2778 if (retval) {
2779 pr_err("network register fail %d\n", retval);
2780 dlci_net_free(dlci);
2781 return retval;
2782 }
2783 return net->ifindex; /* return network index */
2784}
2785
2786/* Line discipline for real tty */
2787struct tty_ldisc_ops tty_ldisc_packet = {
2788 .owner = THIS_MODULE,
2789 .magic = TTY_LDISC_MAGIC,
2790 .name = "n_gsm",
2791 .open = gsmld_open,
2792 .close = gsmld_close,
2793 .flush_buffer = gsmld_flush_buffer,
2794 .chars_in_buffer = gsmld_chars_in_buffer,
2795 .read = gsmld_read,
2796 .write = gsmld_write,
2797 .ioctl = gsmld_ioctl,
2798 .poll = gsmld_poll,
2799 .receive_buf = gsmld_receive_buf,
2800 .write_wakeup = gsmld_write_wakeup
2801};
2802
2803/*
2804 * Virtual tty side
2805 */
2806
2807#define TX_SIZE 512
2808
2809static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk)
2810{
2811 u8 modembits[5];
2812 struct gsm_control *ctrl;
2813 int len = 2;
2814
2815 if (brk)
2816 len++;
2817
2818 modembits[0] = len << 1 | EA; /* Data bytes */
2819 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */
2820 modembits[2] = gsm_encode_modem(dlci) << 1 | EA;
2821 if (brk)
2822 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */
2823 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1);
2824 if (ctrl == NULL)
2825 return -ENOMEM;
2826 return gsm_control_wait(dlci->gsm, ctrl);
2827}
2828
2829static int gsm_carrier_raised(struct tty_port *port)
2830{
2831 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2832 /* Not yet open so no carrier info */
2833 if (dlci->state != DLCI_OPEN)
2834 return 0;
2835 if (debug & 2)
2836 return 1;
2837 return dlci->modem_rx & TIOCM_CD;
2838}
2839
2840static void gsm_dtr_rts(struct tty_port *port, int onoff)
2841{
2842 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2843 unsigned int modem_tx = dlci->modem_tx;
2844 if (onoff)
2845 modem_tx |= TIOCM_DTR | TIOCM_RTS;
2846 else
2847 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
2848 if (modem_tx != dlci->modem_tx) {
2849 dlci->modem_tx = modem_tx;
2850 gsmtty_modem_update(dlci, 0);
2851 }
2852}
2853
2854static const struct tty_port_operations gsm_port_ops = {
2855 .carrier_raised = gsm_carrier_raised,
2856 .dtr_rts = gsm_dtr_rts,
2857};
2858
2859
2860static int gsmtty_open(struct tty_struct *tty, struct file *filp)
2861{
2862 struct gsm_mux *gsm;
2863 struct gsm_dlci *dlci;
2864 struct tty_port *port;
2865 unsigned int line = tty->index;
2866 unsigned int mux = line >> 6;
2867
2868 line = line & 0x3F;
2869
2870 if (mux >= MAX_MUX)
2871 return -ENXIO;
2872 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
2873 if (gsm_mux[mux] == NULL)
2874 return -EUNATCH;
2875 if (line == 0 || line > 61) /* 62/63 reserved */
2876 return -ECHRNG;
2877 gsm = gsm_mux[mux];
2878 if (gsm->dead)
2879 return -EL2HLT;
2880 dlci = gsm->dlci[line];
2881 if (dlci == NULL)
2882 dlci = gsm_dlci_alloc(gsm, line);
2883 if (dlci == NULL)
2884 return -ENOMEM;
2885 port = &dlci->port;
2886 port->count++;
2887 tty->driver_data = dlci;
2888 dlci_get(dlci);
2889 dlci_get(dlci->gsm->dlci[0]);
2890 mux_get(dlci->gsm);
2891 tty_port_tty_set(port, tty);
2892
2893 dlci->modem_rx = 0;
2894 /* We could in theory open and close before we wait - eg if we get
2895 a DM straight back. This is ok as that will have caused a hangup */
2896 set_bit(ASYNCB_INITIALIZED, &port->flags);
2897 /* Start sending off SABM messages */
2898 gsm_dlci_begin_open(dlci);
2899 /* And wait for virtual carrier */
2900 return tty_port_block_til_ready(port, tty, filp);
2901}
2902
2903static void gsmtty_close(struct tty_struct *tty, struct file *filp)
2904{
2905 struct gsm_dlci *dlci = tty->driver_data;
2906 struct gsm_mux *gsm;
2907
2908 if (dlci == NULL)
2909 return;
2910 mutex_lock(&dlci->mutex);
2911 gsm_destroy_network(dlci);
2912 mutex_unlock(&dlci->mutex);
2913 gsm = dlci->gsm;
2914 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
2915 goto out;
2916 gsm_dlci_begin_close(dlci);
2917 tty_port_close_end(&dlci->port, tty);
2918 tty_port_tty_set(&dlci->port, NULL);
2919out:
2920 dlci_put(dlci);
2921 dlci_put(gsm->dlci[0]);
2922 mux_put(gsm);
2923}
2924
2925static void gsmtty_hangup(struct tty_struct *tty)
2926{
2927 struct gsm_dlci *dlci = tty->driver_data;
2928 tty_port_hangup(&dlci->port);
2929 gsm_dlci_begin_close(dlci);
2930}
2931
2932static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf,
2933 int len)
2934{
2935 struct gsm_dlci *dlci = tty->driver_data;
2936 /* Stuff the bytes into the fifo queue */
2937 int sent = kfifo_in_locked(dlci->fifo, buf, len, &dlci->lock);
2938 /* Need to kick the channel */
2939 gsm_dlci_data_kick(dlci);
2940 return sent;
2941}
2942
2943static int gsmtty_write_room(struct tty_struct *tty)
2944{
2945 struct gsm_dlci *dlci = tty->driver_data;
2946 return TX_SIZE - kfifo_len(dlci->fifo);
2947}
2948
2949static int gsmtty_chars_in_buffer(struct tty_struct *tty)
2950{
2951 struct gsm_dlci *dlci = tty->driver_data;
2952 return kfifo_len(dlci->fifo);
2953}
2954
2955static void gsmtty_flush_buffer(struct tty_struct *tty)
2956{
2957 struct gsm_dlci *dlci = tty->driver_data;
2958 /* Caution needed: If we implement reliable transport classes
2959 then the data being transmitted can't simply be junked once
2960 it has first hit the stack. Until then we can just blow it
2961 away */
2962 kfifo_reset(dlci->fifo);
2963 /* Need to unhook this DLCI from the transmit queue logic */
2964}
2965
2966static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
2967{
2968 /* The FIFO handles the queue so the kernel will do the right
2969 thing waiting on chars_in_buffer before calling us. No work
2970 to do here */
2971}
2972
2973static int gsmtty_tiocmget(struct tty_struct *tty)
2974{
2975 struct gsm_dlci *dlci = tty->driver_data;
2976 return dlci->modem_rx;
2977}
2978
2979static int gsmtty_tiocmset(struct tty_struct *tty,
2980 unsigned int set, unsigned int clear)
2981{
2982 struct gsm_dlci *dlci = tty->driver_data;
2983 unsigned int modem_tx = dlci->modem_tx;
2984
2985 modem_tx &= clear;
2986 modem_tx |= set;
2987
2988 if (modem_tx != dlci->modem_tx) {
2989 dlci->modem_tx = modem_tx;
2990 return gsmtty_modem_update(dlci, 0);
2991 }
2992 return 0;
2993}
2994
2995
2996static int gsmtty_ioctl(struct tty_struct *tty,
2997 unsigned int cmd, unsigned long arg)
2998{
2999 struct gsm_dlci *dlci = tty->driver_data;
3000 struct gsm_netconfig nc;
3001 int index;
3002
3003 switch (cmd) {
3004 case GSMIOC_ENABLE_NET:
3005 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc)))
3006 return -EFAULT;
3007 nc.if_name[IFNAMSIZ-1] = '\0';
3008 /* return net interface index or error code */
3009 mutex_lock(&dlci->mutex);
3010 index = gsm_create_network(dlci, &nc);
3011 mutex_unlock(&dlci->mutex);
3012 if (copy_to_user((void __user *)arg, &nc, sizeof(nc)))
3013 return -EFAULT;
3014 return index;
3015 case GSMIOC_DISABLE_NET:
3016 if (!capable(CAP_NET_ADMIN))
3017 return -EPERM;
3018 mutex_lock(&dlci->mutex);
3019 gsm_destroy_network(dlci);
3020 mutex_unlock(&dlci->mutex);
3021 return 0;
3022 default:
3023 return -ENOIOCTLCMD;
3024 }
3025}
3026
3027static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old)
3028{
3029 /* For the moment its fixed. In actual fact the speed information
3030 for the virtual channel can be propogated in both directions by
3031 the RPN control message. This however rapidly gets nasty as we
3032 then have to remap modem signals each way according to whether
3033 our virtual cable is null modem etc .. */
3034 tty_termios_copy_hw(tty->termios, old);
3035}
3036
3037static void gsmtty_throttle(struct tty_struct *tty)
3038{
3039 struct gsm_dlci *dlci = tty->driver_data;
3040 if (tty->termios->c_cflag & CRTSCTS)
3041 dlci->modem_tx &= ~TIOCM_DTR;
3042 dlci->throttled = 1;
3043 /* Send an MSC with DTR cleared */
3044 gsmtty_modem_update(dlci, 0);
3045}
3046
3047static void gsmtty_unthrottle(struct tty_struct *tty)
3048{
3049 struct gsm_dlci *dlci = tty->driver_data;
3050 if (tty->termios->c_cflag & CRTSCTS)
3051 dlci->modem_tx |= TIOCM_DTR;
3052 dlci->throttled = 0;
3053 /* Send an MSC with DTR set */
3054 gsmtty_modem_update(dlci, 0);
3055}
3056
3057static int gsmtty_break_ctl(struct tty_struct *tty, int state)
3058{
3059 struct gsm_dlci *dlci = tty->driver_data;
3060 int encode = 0; /* Off */
3061
3062 if (state == -1) /* "On indefinitely" - we can't encode this
3063 properly */
3064 encode = 0x0F;
3065 else if (state > 0) {
3066 encode = state / 200; /* mS to encoding */
3067 if (encode > 0x0F)
3068 encode = 0x0F; /* Best effort */
3069 }
3070 return gsmtty_modem_update(dlci, encode);
3071}
3072
3073
3074/* Virtual ttys for the demux */
3075static const struct tty_operations gsmtty_ops = {
3076 .open = gsmtty_open,
3077 .close = gsmtty_close,
3078 .write = gsmtty_write,
3079 .write_room = gsmtty_write_room,
3080 .chars_in_buffer = gsmtty_chars_in_buffer,
3081 .flush_buffer = gsmtty_flush_buffer,
3082 .ioctl = gsmtty_ioctl,
3083 .throttle = gsmtty_throttle,
3084 .unthrottle = gsmtty_unthrottle,
3085 .set_termios = gsmtty_set_termios,
3086 .hangup = gsmtty_hangup,
3087 .wait_until_sent = gsmtty_wait_until_sent,
3088 .tiocmget = gsmtty_tiocmget,
3089 .tiocmset = gsmtty_tiocmset,
3090 .break_ctl = gsmtty_break_ctl,
3091};
3092
3093
3094
3095static int __init gsm_init(void)
3096{
3097 /* Fill in our line protocol discipline, and register it */
3098 int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet);
3099 if (status != 0) {
3100 pr_err("n_gsm: can't register line discipline (err = %d)\n",
3101 status);
3102 return status;
3103 }
3104
3105 gsm_tty_driver = alloc_tty_driver(256);
3106 if (!gsm_tty_driver) {
3107 tty_unregister_ldisc(N_GSM0710);
3108 pr_err("gsm_init: tty allocation failed.\n");
3109 return -EINVAL;
3110 }
3111 gsm_tty_driver->owner = THIS_MODULE;
3112 gsm_tty_driver->driver_name = "gsmtty";
3113 gsm_tty_driver->name = "gsmtty";
3114 gsm_tty_driver->major = 0; /* Dynamic */
3115 gsm_tty_driver->minor_start = 0;
3116 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
3117 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
3118 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV
3119 | TTY_DRIVER_HARDWARE_BREAK;
3120 gsm_tty_driver->init_termios = tty_std_termios;
3121 /* Fixme */
3122 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
3123 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
3124
3125 spin_lock_init(&gsm_mux_lock);
3126
3127 if (tty_register_driver(gsm_tty_driver)) {
3128 put_tty_driver(gsm_tty_driver);
3129 tty_unregister_ldisc(N_GSM0710);
3130 pr_err("gsm_init: tty registration failed.\n");
3131 return -EBUSY;
3132 }
3133 pr_debug("gsm_init: loaded as %d,%d.\n",
3134 gsm_tty_driver->major, gsm_tty_driver->minor_start);
3135 return 0;
3136}
3137
3138static void __exit gsm_exit(void)
3139{
3140 int status = tty_unregister_ldisc(N_GSM0710);
3141 if (status != 0)
3142 pr_err("n_gsm: can't unregister line discipline (err = %d)\n",
3143 status);
3144 tty_unregister_driver(gsm_tty_driver);
3145 put_tty_driver(gsm_tty_driver);
3146}
3147
3148module_init(gsm_init);
3149module_exit(gsm_exit);
3150
3151
3152MODULE_LICENSE("GPL");
3153MODULE_ALIAS_LDISC(N_GSM0710);
1/*
2 * n_gsm.c GSM 0710 tty multiplexor
3 * Copyright (c) 2009/10 Intel Corporation
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
17 *
18 * * THIS IS A DEVELOPMENT SNAPSHOT IT IS NOT A FINAL RELEASE *
19 *
20 * TO DO:
21 * Mostly done: ioctls for setting modes/timing
22 * Partly done: hooks so you can pull off frames to non tty devs
23 * Restart DLCI 0 when it closes ?
24 * Improve the tx engine
25 * Resolve tx side locking by adding a queue_head and routing
26 * all control traffic via it
27 * General tidy/document
28 * Review the locking/move to refcounts more (mux now moved to an
29 * alloc/free model ready)
30 * Use newest tty open/close port helpers and install hooks
31 * What to do about power functions ?
32 * Termios setting and negotiation
33 * Do we need a 'which mux are you' ioctl to correlate mux and tty sets
34 *
35 */
36
37#include <linux/types.h>
38#include <linux/major.h>
39#include <linux/errno.h>
40#include <linux/signal.h>
41#include <linux/fcntl.h>
42#include <linux/sched.h>
43#include <linux/interrupt.h>
44#include <linux/tty.h>
45#include <linux/ctype.h>
46#include <linux/mm.h>
47#include <linux/string.h>
48#include <linux/slab.h>
49#include <linux/poll.h>
50#include <linux/bitops.h>
51#include <linux/file.h>
52#include <linux/uaccess.h>
53#include <linux/module.h>
54#include <linux/timer.h>
55#include <linux/tty_flip.h>
56#include <linux/tty_driver.h>
57#include <linux/serial.h>
58#include <linux/kfifo.h>
59#include <linux/skbuff.h>
60#include <net/arp.h>
61#include <linux/ip.h>
62#include <linux/netdevice.h>
63#include <linux/etherdevice.h>
64#include <linux/gsmmux.h>
65
66static int debug;
67module_param(debug, int, 0600);
68
69/* Defaults: these are from the specification */
70
71#define T1 10 /* 100mS */
72#define T2 34 /* 333mS */
73#define N2 3 /* Retry 3 times */
74
75/* Use long timers for testing at low speed with debug on */
76#ifdef DEBUG_TIMING
77#define T1 100
78#define T2 200
79#endif
80
81/*
82 * Semi-arbitrary buffer size limits. 0710 is normally run with 32-64 byte
83 * limits so this is plenty
84 */
85#define MAX_MRU 1500
86#define MAX_MTU 1500
87#define GSM_NET_TX_TIMEOUT (HZ*10)
88
89/**
90 * struct gsm_mux_net - network interface
91 * @struct gsm_dlci* dlci
92 * @struct net_device_stats stats;
93 *
94 * Created when net interface is initialized.
95 **/
96struct gsm_mux_net {
97 struct kref ref;
98 struct gsm_dlci *dlci;
99 struct net_device_stats stats;
100};
101
102#define STATS(net) (((struct gsm_mux_net *)netdev_priv(net))->stats)
103
104/*
105 * Each block of data we have queued to go out is in the form of
106 * a gsm_msg which holds everything we need in a link layer independent
107 * format
108 */
109
110struct gsm_msg {
111 struct list_head list;
112 u8 addr; /* DLCI address + flags */
113 u8 ctrl; /* Control byte + flags */
114 unsigned int len; /* Length of data block (can be zero) */
115 unsigned char *data; /* Points into buffer but not at the start */
116 unsigned char buffer[0];
117};
118
119/*
120 * Each active data link has a gsm_dlci structure associated which ties
121 * the link layer to an optional tty (if the tty side is open). To avoid
122 * complexity right now these are only ever freed up when the mux is
123 * shut down.
124 *
125 * At the moment we don't free DLCI objects until the mux is torn down
126 * this avoid object life time issues but might be worth review later.
127 */
128
129struct gsm_dlci {
130 struct gsm_mux *gsm;
131 int addr;
132 int state;
133#define DLCI_CLOSED 0
134#define DLCI_OPENING 1 /* Sending SABM not seen UA */
135#define DLCI_OPEN 2 /* SABM/UA complete */
136#define DLCI_CLOSING 3 /* Sending DISC not seen UA/DM */
137 struct mutex mutex;
138
139 /* Link layer */
140 spinlock_t lock; /* Protects the internal state */
141 struct timer_list t1; /* Retransmit timer for SABM and UA */
142 int retries;
143 /* Uplink tty if active */
144 struct tty_port port; /* The tty bound to this DLCI if there is one */
145 struct kfifo *fifo; /* Queue fifo for the DLCI */
146 struct kfifo _fifo; /* For new fifo API porting only */
147 int adaption; /* Adaption layer in use */
148 int prev_adaption;
149 u32 modem_rx; /* Our incoming virtual modem lines */
150 u32 modem_tx; /* Our outgoing modem lines */
151 int dead; /* Refuse re-open */
152 /* Flow control */
153 int throttled; /* Private copy of throttle state */
154 int constipated; /* Throttle status for outgoing */
155 /* Packetised I/O */
156 struct sk_buff *skb; /* Frame being sent */
157 struct sk_buff_head skb_list; /* Queued frames */
158 /* Data handling callback */
159 void (*data)(struct gsm_dlci *dlci, u8 *data, int len);
160 void (*prev_data)(struct gsm_dlci *dlci, u8 *data, int len);
161 struct net_device *net; /* network interface, if created */
162};
163
164/* DLCI 0, 62/63 are special or reserved see gsmtty_open */
165
166#define NUM_DLCI 64
167
168/*
169 * DLCI 0 is used to pass control blocks out of band of the data
170 * flow (and with a higher link priority). One command can be outstanding
171 * at a time and we use this structure to manage them. They are created
172 * and destroyed by the user context, and updated by the receive paths
173 * and timers
174 */
175
176struct gsm_control {
177 u8 cmd; /* Command we are issuing */
178 u8 *data; /* Data for the command in case we retransmit */
179 int len; /* Length of block for retransmission */
180 int done; /* Done flag */
181 int error; /* Error if any */
182};
183
184/*
185 * Each GSM mux we have is represented by this structure. If we are
186 * operating as an ldisc then we use this structure as our ldisc
187 * state. We need to sort out lifetimes and locking with respect
188 * to the gsm mux array. For now we don't free DLCI objects that
189 * have been instantiated until the mux itself is terminated.
190 *
191 * To consider further: tty open versus mux shutdown.
192 */
193
194struct gsm_mux {
195 struct tty_struct *tty; /* The tty our ldisc is bound to */
196 spinlock_t lock;
197 struct mutex mutex;
198 unsigned int num;
199 struct kref ref;
200
201 /* Events on the GSM channel */
202 wait_queue_head_t event;
203
204 /* Bits for GSM mode decoding */
205
206 /* Framing Layer */
207 unsigned char *buf;
208 int state;
209#define GSM_SEARCH 0
210#define GSM_START 1
211#define GSM_ADDRESS 2
212#define GSM_CONTROL 3
213#define GSM_LEN 4
214#define GSM_DATA 5
215#define GSM_FCS 6
216#define GSM_OVERRUN 7
217#define GSM_LEN0 8
218#define GSM_LEN1 9
219#define GSM_SSOF 10
220 unsigned int len;
221 unsigned int address;
222 unsigned int count;
223 int escape;
224 int encoding;
225 u8 control;
226 u8 fcs;
227 u8 received_fcs;
228 u8 *txframe; /* TX framing buffer */
229
230 /* Methods for the receiver side */
231 void (*receive)(struct gsm_mux *gsm, u8 ch);
232 void (*error)(struct gsm_mux *gsm, u8 ch, u8 flag);
233 /* And transmit side */
234 int (*output)(struct gsm_mux *mux, u8 *data, int len);
235
236 /* Link Layer */
237 unsigned int mru;
238 unsigned int mtu;
239 int initiator; /* Did we initiate connection */
240 int dead; /* Has the mux been shut down */
241 struct gsm_dlci *dlci[NUM_DLCI];
242 int constipated; /* Asked by remote to shut up */
243
244 spinlock_t tx_lock;
245 unsigned int tx_bytes; /* TX data outstanding */
246#define TX_THRESH_HI 8192
247#define TX_THRESH_LO 2048
248 struct list_head tx_list; /* Pending data packets */
249
250 /* Control messages */
251 struct timer_list t2_timer; /* Retransmit timer for commands */
252 int cretries; /* Command retry counter */
253 struct gsm_control *pending_cmd;/* Our current pending command */
254 spinlock_t control_lock; /* Protects the pending command */
255
256 /* Configuration */
257 int adaption; /* 1 or 2 supported */
258 u8 ftype; /* UI or UIH */
259 int t1, t2; /* Timers in 1/100th of a sec */
260 int n2; /* Retry count */
261
262 /* Statistics (not currently exposed) */
263 unsigned long bad_fcs;
264 unsigned long malformed;
265 unsigned long io_error;
266 unsigned long bad_size;
267 unsigned long unsupported;
268};
269
270
271/*
272 * Mux objects - needed so that we can translate a tty index into the
273 * relevant mux and DLCI.
274 */
275
276#define MAX_MUX 4 /* 256 minors */
277static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */
278static spinlock_t gsm_mux_lock;
279
280static struct tty_driver *gsm_tty_driver;
281
282/*
283 * This section of the driver logic implements the GSM encodings
284 * both the basic and the 'advanced'. Reliable transport is not
285 * supported.
286 */
287
288#define CR 0x02
289#define EA 0x01
290#define PF 0x10
291
292/* I is special: the rest are ..*/
293#define RR 0x01
294#define UI 0x03
295#define RNR 0x05
296#define REJ 0x09
297#define DM 0x0F
298#define SABM 0x2F
299#define DISC 0x43
300#define UA 0x63
301#define UIH 0xEF
302
303/* Channel commands */
304#define CMD_NSC 0x09
305#define CMD_TEST 0x11
306#define CMD_PSC 0x21
307#define CMD_RLS 0x29
308#define CMD_FCOFF 0x31
309#define CMD_PN 0x41
310#define CMD_RPN 0x49
311#define CMD_FCON 0x51
312#define CMD_CLD 0x61
313#define CMD_SNC 0x69
314#define CMD_MSC 0x71
315
316/* Virtual modem bits */
317#define MDM_FC 0x01
318#define MDM_RTC 0x02
319#define MDM_RTR 0x04
320#define MDM_IC 0x20
321#define MDM_DV 0x40
322
323#define GSM0_SOF 0xF9
324#define GSM1_SOF 0x7E
325#define GSM1_ESCAPE 0x7D
326#define GSM1_ESCAPE_BITS 0x20
327#define XON 0x11
328#define XOFF 0x13
329
330static const struct tty_port_operations gsm_port_ops;
331
332/*
333 * CRC table for GSM 0710
334 */
335
336static const u8 gsm_fcs8[256] = {
337 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75,
338 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B,
339 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69,
340 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67,
341 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D,
342 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43,
343 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51,
344 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F,
345 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05,
346 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B,
347 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19,
348 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17,
349 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D,
350 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33,
351 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21,
352 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F,
353 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95,
354 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B,
355 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89,
356 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87,
357 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD,
358 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3,
359 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1,
360 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF,
361 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5,
362 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB,
363 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9,
364 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7,
365 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD,
366 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3,
367 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1,
368 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF
369};
370
371#define INIT_FCS 0xFF
372#define GOOD_FCS 0xCF
373
374/**
375 * gsm_fcs_add - update FCS
376 * @fcs: Current FCS
377 * @c: Next data
378 *
379 * Update the FCS to include c. Uses the algorithm in the specification
380 * notes.
381 */
382
383static inline u8 gsm_fcs_add(u8 fcs, u8 c)
384{
385 return gsm_fcs8[fcs ^ c];
386}
387
388/**
389 * gsm_fcs_add_block - update FCS for a block
390 * @fcs: Current FCS
391 * @c: buffer of data
392 * @len: length of buffer
393 *
394 * Update the FCS to include c. Uses the algorithm in the specification
395 * notes.
396 */
397
398static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len)
399{
400 while (len--)
401 fcs = gsm_fcs8[fcs ^ *c++];
402 return fcs;
403}
404
405/**
406 * gsm_read_ea - read a byte into an EA
407 * @val: variable holding value
408 * c: byte going into the EA
409 *
410 * Processes one byte of an EA. Updates the passed variable
411 * and returns 1 if the EA is now completely read
412 */
413
414static int gsm_read_ea(unsigned int *val, u8 c)
415{
416 /* Add the next 7 bits into the value */
417 *val <<= 7;
418 *val |= c >> 1;
419 /* Was this the last byte of the EA 1 = yes*/
420 return c & EA;
421}
422
423/**
424 * gsm_encode_modem - encode modem data bits
425 * @dlci: DLCI to encode from
426 *
427 * Returns the correct GSM encoded modem status bits (6 bit field) for
428 * the current status of the DLCI and attached tty object
429 */
430
431static u8 gsm_encode_modem(const struct gsm_dlci *dlci)
432{
433 u8 modembits = 0;
434 /* FC is true flow control not modem bits */
435 if (dlci->throttled)
436 modembits |= MDM_FC;
437 if (dlci->modem_tx & TIOCM_DTR)
438 modembits |= MDM_RTC;
439 if (dlci->modem_tx & TIOCM_RTS)
440 modembits |= MDM_RTR;
441 if (dlci->modem_tx & TIOCM_RI)
442 modembits |= MDM_IC;
443 if (dlci->modem_tx & TIOCM_CD)
444 modembits |= MDM_DV;
445 return modembits;
446}
447
448/**
449 * gsm_print_packet - display a frame for debug
450 * @hdr: header to print before decode
451 * @addr: address EA from the frame
452 * @cr: C/R bit from the frame
453 * @control: control including PF bit
454 * @data: following data bytes
455 * @dlen: length of data
456 *
457 * Displays a packet in human readable format for debugging purposes. The
458 * style is based on amateur radio LAP-B dump display.
459 */
460
461static void gsm_print_packet(const char *hdr, int addr, int cr,
462 u8 control, const u8 *data, int dlen)
463{
464 if (!(debug & 1))
465 return;
466
467 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]);
468
469 switch (control & ~PF) {
470 case SABM:
471 pr_cont("SABM");
472 break;
473 case UA:
474 pr_cont("UA");
475 break;
476 case DISC:
477 pr_cont("DISC");
478 break;
479 case DM:
480 pr_cont("DM");
481 break;
482 case UI:
483 pr_cont("UI");
484 break;
485 case UIH:
486 pr_cont("UIH");
487 break;
488 default:
489 if (!(control & 0x01)) {
490 pr_cont("I N(S)%d N(R)%d",
491 (control & 0x0E) >> 1, (control & 0xE0) >> 5);
492 } else switch (control & 0x0F) {
493 case RR:
494 pr_cont("RR(%d)", (control & 0xE0) >> 5);
495 break;
496 case RNR:
497 pr_cont("RNR(%d)", (control & 0xE0) >> 5);
498 break;
499 case REJ:
500 pr_cont("REJ(%d)", (control & 0xE0) >> 5);
501 break;
502 default:
503 pr_cont("[%02X]", control);
504 }
505 }
506
507 if (control & PF)
508 pr_cont("(P)");
509 else
510 pr_cont("(F)");
511
512 if (dlen) {
513 int ct = 0;
514 while (dlen--) {
515 if (ct % 8 == 0) {
516 pr_cont("\n");
517 pr_debug(" ");
518 }
519 pr_cont("%02X ", *data++);
520 ct++;
521 }
522 }
523 pr_cont("\n");
524}
525
526
527/*
528 * Link level transmission side
529 */
530
531/**
532 * gsm_stuff_packet - bytestuff a packet
533 * @ibuf: input
534 * @obuf: output
535 * @len: length of input
536 *
537 * Expand a buffer by bytestuffing it. The worst case size change
538 * is doubling and the caller is responsible for handing out
539 * suitable sized buffers.
540 */
541
542static int gsm_stuff_frame(const u8 *input, u8 *output, int len)
543{
544 int olen = 0;
545 while (len--) {
546 if (*input == GSM1_SOF || *input == GSM1_ESCAPE
547 || *input == XON || *input == XOFF) {
548 *output++ = GSM1_ESCAPE;
549 *output++ = *input++ ^ GSM1_ESCAPE_BITS;
550 olen++;
551 } else
552 *output++ = *input++;
553 olen++;
554 }
555 return olen;
556}
557
558/**
559 * gsm_send - send a control frame
560 * @gsm: our GSM mux
561 * @addr: address for control frame
562 * @cr: command/response bit
563 * @control: control byte including PF bit
564 *
565 * Format up and transmit a control frame. These do not go via the
566 * queueing logic as they should be transmitted ahead of data when
567 * they are needed.
568 *
569 * FIXME: Lock versus data TX path
570 */
571
572static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control)
573{
574 int len;
575 u8 cbuf[10];
576 u8 ibuf[3];
577
578 switch (gsm->encoding) {
579 case 0:
580 cbuf[0] = GSM0_SOF;
581 cbuf[1] = (addr << 2) | (cr << 1) | EA;
582 cbuf[2] = control;
583 cbuf[3] = EA; /* Length of data = 0 */
584 cbuf[4] = 0xFF - gsm_fcs_add_block(INIT_FCS, cbuf + 1, 3);
585 cbuf[5] = GSM0_SOF;
586 len = 6;
587 break;
588 case 1:
589 case 2:
590 /* Control frame + packing (but not frame stuffing) in mode 1 */
591 ibuf[0] = (addr << 2) | (cr << 1) | EA;
592 ibuf[1] = control;
593 ibuf[2] = 0xFF - gsm_fcs_add_block(INIT_FCS, ibuf, 2);
594 /* Stuffing may double the size worst case */
595 len = gsm_stuff_frame(ibuf, cbuf + 1, 3);
596 /* Now add the SOF markers */
597 cbuf[0] = GSM1_SOF;
598 cbuf[len + 1] = GSM1_SOF;
599 /* FIXME: we can omit the lead one in many cases */
600 len += 2;
601 break;
602 default:
603 WARN_ON(1);
604 return;
605 }
606 gsm->output(gsm, cbuf, len);
607 gsm_print_packet("-->", addr, cr, control, NULL, 0);
608}
609
610/**
611 * gsm_response - send a control response
612 * @gsm: our GSM mux
613 * @addr: address for control frame
614 * @control: control byte including PF bit
615 *
616 * Format up and transmit a link level response frame.
617 */
618
619static inline void gsm_response(struct gsm_mux *gsm, int addr, int control)
620{
621 gsm_send(gsm, addr, 0, control);
622}
623
624/**
625 * gsm_command - send a control command
626 * @gsm: our GSM mux
627 * @addr: address for control frame
628 * @control: control byte including PF bit
629 *
630 * Format up and transmit a link level command frame.
631 */
632
633static inline void gsm_command(struct gsm_mux *gsm, int addr, int control)
634{
635 gsm_send(gsm, addr, 1, control);
636}
637
638/* Data transmission */
639
640#define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */
641
642/**
643 * gsm_data_alloc - allocate data frame
644 * @gsm: GSM mux
645 * @addr: DLCI address
646 * @len: length excluding header and FCS
647 * @ctrl: control byte
648 *
649 * Allocate a new data buffer for sending frames with data. Space is left
650 * at the front for header bytes but that is treated as an implementation
651 * detail and not for the high level code to use
652 */
653
654static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
655 u8 ctrl)
656{
657 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN,
658 GFP_ATOMIC);
659 if (m == NULL)
660 return NULL;
661 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */
662 m->len = len;
663 m->addr = addr;
664 m->ctrl = ctrl;
665 INIT_LIST_HEAD(&m->list);
666 return m;
667}
668
669/**
670 * gsm_data_kick - poke the queue
671 * @gsm: GSM Mux
672 *
673 * The tty device has called us to indicate that room has appeared in
674 * the transmit queue. Ram more data into the pipe if we have any
675 * If we have been flow-stopped by a CMD_FCOFF, then we can only
676 * send messages on DLCI0 until CMD_FCON
677 *
678 * FIXME: lock against link layer control transmissions
679 */
680
681static void gsm_data_kick(struct gsm_mux *gsm)
682{
683 struct gsm_msg *msg, *nmsg;
684 int len;
685 int skip_sof = 0;
686
687 list_for_each_entry_safe(msg, nmsg, &gsm->tx_list, list) {
688 if (gsm->constipated && msg->addr)
689 continue;
690 if (gsm->encoding != 0) {
691 gsm->txframe[0] = GSM1_SOF;
692 len = gsm_stuff_frame(msg->data,
693 gsm->txframe + 1, msg->len);
694 gsm->txframe[len + 1] = GSM1_SOF;
695 len += 2;
696 } else {
697 gsm->txframe[0] = GSM0_SOF;
698 memcpy(gsm->txframe + 1 , msg->data, msg->len);
699 gsm->txframe[msg->len + 1] = GSM0_SOF;
700 len = msg->len + 2;
701 }
702
703 if (debug & 4)
704 print_hex_dump_bytes("gsm_data_kick: ",
705 DUMP_PREFIX_OFFSET,
706 gsm->txframe, len);
707
708 if (gsm->output(gsm, gsm->txframe + skip_sof,
709 len - skip_sof) < 0)
710 break;
711 /* FIXME: Can eliminate one SOF in many more cases */
712 gsm->tx_bytes -= msg->len;
713 /* For a burst of frames skip the extra SOF within the
714 burst */
715 skip_sof = 1;
716
717 list_del(&msg->list);
718 kfree(msg);
719 }
720}
721
722/**
723 * __gsm_data_queue - queue a UI or UIH frame
724 * @dlci: DLCI sending the data
725 * @msg: message queued
726 *
727 * Add data to the transmit queue and try and get stuff moving
728 * out of the mux tty if not already doing so. The Caller must hold
729 * the gsm tx lock.
730 */
731
732static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
733{
734 struct gsm_mux *gsm = dlci->gsm;
735 u8 *dp = msg->data;
736 u8 *fcs = dp + msg->len;
737
738 /* Fill in the header */
739 if (gsm->encoding == 0) {
740 if (msg->len < 128)
741 *--dp = (msg->len << 1) | EA;
742 else {
743 *--dp = (msg->len >> 7); /* bits 7 - 15 */
744 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */
745 }
746 }
747
748 *--dp = msg->ctrl;
749 if (gsm->initiator)
750 *--dp = (msg->addr << 2) | 2 | EA;
751 else
752 *--dp = (msg->addr << 2) | EA;
753 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp);
754 /* Ugly protocol layering violation */
755 if (msg->ctrl == UI || msg->ctrl == (UI|PF))
756 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len);
757 *fcs = 0xFF - *fcs;
758
759 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl,
760 msg->data, msg->len);
761
762 /* Move the header back and adjust the length, also allow for the FCS
763 now tacked on the end */
764 msg->len += (msg->data - dp) + 1;
765 msg->data = dp;
766
767 /* Add to the actual output queue */
768 list_add_tail(&msg->list, &gsm->tx_list);
769 gsm->tx_bytes += msg->len;
770 gsm_data_kick(gsm);
771}
772
773/**
774 * gsm_data_queue - queue a UI or UIH frame
775 * @dlci: DLCI sending the data
776 * @msg: message queued
777 *
778 * Add data to the transmit queue and try and get stuff moving
779 * out of the mux tty if not already doing so. Take the
780 * the gsm tx lock and dlci lock.
781 */
782
783static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
784{
785 unsigned long flags;
786 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
787 __gsm_data_queue(dlci, msg);
788 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
789}
790
791/**
792 * gsm_dlci_data_output - try and push data out of a DLCI
793 * @gsm: mux
794 * @dlci: the DLCI to pull data from
795 *
796 * Pull data from a DLCI and send it into the transmit queue if there
797 * is data. Keep to the MRU of the mux. This path handles the usual tty
798 * interface which is a byte stream with optional modem data.
799 *
800 * Caller must hold the tx_lock of the mux.
801 */
802
803static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci)
804{
805 struct gsm_msg *msg;
806 u8 *dp;
807 int len, total_size, size;
808 int h = dlci->adaption - 1;
809
810 total_size = 0;
811 while (1) {
812 len = kfifo_len(dlci->fifo);
813 if (len == 0)
814 return total_size;
815
816 /* MTU/MRU count only the data bits */
817 if (len > gsm->mtu)
818 len = gsm->mtu;
819
820 size = len + h;
821
822 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
823 /* FIXME: need a timer or something to kick this so it can't
824 get stuck with no work outstanding and no buffer free */
825 if (msg == NULL)
826 return -ENOMEM;
827 dp = msg->data;
828 switch (dlci->adaption) {
829 case 1: /* Unstructured */
830 break;
831 case 2: /* Unstructed with modem bits.
832 Always one byte as we never send inline break data */
833 *dp++ = gsm_encode_modem(dlci);
834 break;
835 }
836 WARN_ON(kfifo_out_locked(dlci->fifo, dp , len, &dlci->lock) != len);
837 __gsm_data_queue(dlci, msg);
838 total_size += size;
839 }
840 /* Bytes of data we used up */
841 return total_size;
842}
843
844/**
845 * gsm_dlci_data_output_framed - try and push data out of a DLCI
846 * @gsm: mux
847 * @dlci: the DLCI to pull data from
848 *
849 * Pull data from a DLCI and send it into the transmit queue if there
850 * is data. Keep to the MRU of the mux. This path handles framed data
851 * queued as skbuffs to the DLCI.
852 *
853 * Caller must hold the tx_lock of the mux.
854 */
855
856static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
857 struct gsm_dlci *dlci)
858{
859 struct gsm_msg *msg;
860 u8 *dp;
861 int len, size;
862 int last = 0, first = 0;
863 int overhead = 0;
864
865 /* One byte per frame is used for B/F flags */
866 if (dlci->adaption == 4)
867 overhead = 1;
868
869 /* dlci->skb is locked by tx_lock */
870 if (dlci->skb == NULL) {
871 dlci->skb = skb_dequeue_tail(&dlci->skb_list);
872 if (dlci->skb == NULL)
873 return 0;
874 first = 1;
875 }
876 len = dlci->skb->len + overhead;
877
878 /* MTU/MRU count only the data bits */
879 if (len > gsm->mtu) {
880 if (dlci->adaption == 3) {
881 /* Over long frame, bin it */
882 dev_kfree_skb_any(dlci->skb);
883 dlci->skb = NULL;
884 return 0;
885 }
886 len = gsm->mtu;
887 } else
888 last = 1;
889
890 size = len + overhead;
891 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
892
893 /* FIXME: need a timer or something to kick this so it can't
894 get stuck with no work outstanding and no buffer free */
895 if (msg == NULL) {
896 skb_queue_tail(&dlci->skb_list, dlci->skb);
897 dlci->skb = NULL;
898 return -ENOMEM;
899 }
900 dp = msg->data;
901
902 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */
903 /* Flag byte to carry the start/end info */
904 *dp++ = last << 7 | first << 6 | 1; /* EA */
905 len--;
906 }
907 memcpy(dp, dlci->skb->data, len);
908 skb_pull(dlci->skb, len);
909 __gsm_data_queue(dlci, msg);
910 if (last) {
911 dev_kfree_skb_any(dlci->skb);
912 dlci->skb = NULL;
913 }
914 return size;
915}
916
917/**
918 * gsm_dlci_data_sweep - look for data to send
919 * @gsm: the GSM mux
920 *
921 * Sweep the GSM mux channels in priority order looking for ones with
922 * data to send. We could do with optimising this scan a bit. We aim
923 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit
924 * TX_THRESH_LO we get called again
925 *
926 * FIXME: We should round robin between groups and in theory you can
927 * renegotiate DLCI priorities with optional stuff. Needs optimising.
928 */
929
930static void gsm_dlci_data_sweep(struct gsm_mux *gsm)
931{
932 int len;
933 /* Priority ordering: We should do priority with RR of the groups */
934 int i = 1;
935
936 while (i < NUM_DLCI) {
937 struct gsm_dlci *dlci;
938
939 if (gsm->tx_bytes > TX_THRESH_HI)
940 break;
941 dlci = gsm->dlci[i];
942 if (dlci == NULL || dlci->constipated) {
943 i++;
944 continue;
945 }
946 if (dlci->adaption < 3 && !dlci->net)
947 len = gsm_dlci_data_output(gsm, dlci);
948 else
949 len = gsm_dlci_data_output_framed(gsm, dlci);
950 if (len < 0)
951 break;
952 /* DLCI empty - try the next */
953 if (len == 0)
954 i++;
955 }
956}
957
958/**
959 * gsm_dlci_data_kick - transmit if possible
960 * @dlci: DLCI to kick
961 *
962 * Transmit data from this DLCI if the queue is empty. We can't rely on
963 * a tty wakeup except when we filled the pipe so we need to fire off
964 * new data ourselves in other cases.
965 */
966
967static void gsm_dlci_data_kick(struct gsm_dlci *dlci)
968{
969 unsigned long flags;
970 int sweep;
971
972 if (dlci->constipated)
973 return;
974
975 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
976 /* If we have nothing running then we need to fire up */
977 sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO);
978 if (dlci->gsm->tx_bytes == 0) {
979 if (dlci->net)
980 gsm_dlci_data_output_framed(dlci->gsm, dlci);
981 else
982 gsm_dlci_data_output(dlci->gsm, dlci);
983 }
984 if (sweep)
985 gsm_dlci_data_sweep(dlci->gsm);
986 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
987}
988
989/*
990 * Control message processing
991 */
992
993
994/**
995 * gsm_control_reply - send a response frame to a control
996 * @gsm: gsm channel
997 * @cmd: the command to use
998 * @data: data to follow encoded info
999 * @dlen: length of data
1000 *
1001 * Encode up and queue a UI/UIH frame containing our response.
1002 */
1003
1004static void gsm_control_reply(struct gsm_mux *gsm, int cmd, u8 *data,
1005 int dlen)
1006{
1007 struct gsm_msg *msg;
1008 msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype);
1009 if (msg == NULL)
1010 return;
1011 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */
1012 msg->data[1] = (dlen << 1) | EA;
1013 memcpy(msg->data + 2, data, dlen);
1014 gsm_data_queue(gsm->dlci[0], msg);
1015}
1016
1017/**
1018 * gsm_process_modem - process received modem status
1019 * @tty: virtual tty bound to the DLCI
1020 * @dlci: DLCI to affect
1021 * @modem: modem bits (full EA)
1022 *
1023 * Used when a modem control message or line state inline in adaption
1024 * layer 2 is processed. Sort out the local modem state and throttles
1025 */
1026
1027static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
1028 u32 modem, int clen)
1029{
1030 int mlines = 0;
1031 u8 brk = 0;
1032 int fc;
1033
1034 /* The modem status command can either contain one octet (v.24 signals)
1035 or two octets (v.24 signals + break signals). The length field will
1036 either be 2 or 3 respectively. This is specified in section
1037 5.4.6.3.7 of the 27.010 mux spec. */
1038
1039 if (clen == 2)
1040 modem = modem & 0x7f;
1041 else {
1042 brk = modem & 0x7f;
1043 modem = (modem >> 7) & 0x7f;
1044 }
1045
1046 /* Flow control/ready to communicate */
1047 fc = (modem & MDM_FC) || !(modem & MDM_RTR);
1048 if (fc && !dlci->constipated) {
1049 /* Need to throttle our output on this device */
1050 dlci->constipated = 1;
1051 } else if (!fc && dlci->constipated) {
1052 dlci->constipated = 0;
1053 gsm_dlci_data_kick(dlci);
1054 }
1055
1056 /* Map modem bits */
1057 if (modem & MDM_RTC)
1058 mlines |= TIOCM_DSR | TIOCM_DTR;
1059 if (modem & MDM_RTR)
1060 mlines |= TIOCM_RTS | TIOCM_CTS;
1061 if (modem & MDM_IC)
1062 mlines |= TIOCM_RI;
1063 if (modem & MDM_DV)
1064 mlines |= TIOCM_CD;
1065
1066 /* Carrier drop -> hangup */
1067 if (tty) {
1068 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD))
1069 if (!C_CLOCAL(tty))
1070 tty_hangup(tty);
1071 }
1072 if (brk & 0x01)
1073 tty_insert_flip_char(&dlci->port, 0, TTY_BREAK);
1074 dlci->modem_rx = mlines;
1075}
1076
1077/**
1078 * gsm_control_modem - modem status received
1079 * @gsm: GSM channel
1080 * @data: data following command
1081 * @clen: command length
1082 *
1083 * We have received a modem status control message. This is used by
1084 * the GSM mux protocol to pass virtual modem line status and optionally
1085 * to indicate break signals. Unpack it, convert to Linux representation
1086 * and if need be stuff a break message down the tty.
1087 */
1088
1089static void gsm_control_modem(struct gsm_mux *gsm, u8 *data, int clen)
1090{
1091 unsigned int addr = 0;
1092 unsigned int modem = 0;
1093 unsigned int brk = 0;
1094 struct gsm_dlci *dlci;
1095 int len = clen;
1096 u8 *dp = data;
1097 struct tty_struct *tty;
1098
1099 while (gsm_read_ea(&addr, *dp++) == 0) {
1100 len--;
1101 if (len == 0)
1102 return;
1103 }
1104 /* Must be at least one byte following the EA */
1105 len--;
1106 if (len <= 0)
1107 return;
1108
1109 addr >>= 1;
1110 /* Closed port, or invalid ? */
1111 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1112 return;
1113 dlci = gsm->dlci[addr];
1114
1115 while (gsm_read_ea(&modem, *dp++) == 0) {
1116 len--;
1117 if (len == 0)
1118 return;
1119 }
1120 len--;
1121 if (len > 0) {
1122 while (gsm_read_ea(&brk, *dp++) == 0) {
1123 len--;
1124 if (len == 0)
1125 return;
1126 }
1127 modem <<= 7;
1128 modem |= (brk & 0x7f);
1129 }
1130 tty = tty_port_tty_get(&dlci->port);
1131 gsm_process_modem(tty, dlci, modem, clen);
1132 if (tty) {
1133 tty_wakeup(tty);
1134 tty_kref_put(tty);
1135 }
1136 gsm_control_reply(gsm, CMD_MSC, data, clen);
1137}
1138
1139/**
1140 * gsm_control_rls - remote line status
1141 * @gsm: GSM channel
1142 * @data: data bytes
1143 * @clen: data length
1144 *
1145 * The modem sends us a two byte message on the control channel whenever
1146 * it wishes to send us an error state from the virtual link. Stuff
1147 * this into the uplink tty if present
1148 */
1149
1150static void gsm_control_rls(struct gsm_mux *gsm, u8 *data, int clen)
1151{
1152 struct tty_port *port;
1153 unsigned int addr = 0;
1154 u8 bits;
1155 int len = clen;
1156 u8 *dp = data;
1157
1158 while (gsm_read_ea(&addr, *dp++) == 0) {
1159 len--;
1160 if (len == 0)
1161 return;
1162 }
1163 /* Must be at least one byte following ea */
1164 len--;
1165 if (len <= 0)
1166 return;
1167 addr >>= 1;
1168 /* Closed port, or invalid ? */
1169 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1170 return;
1171 /* No error ? */
1172 bits = *dp;
1173 if ((bits & 1) == 0)
1174 return;
1175
1176 port = &gsm->dlci[addr]->port;
1177
1178 if (bits & 2)
1179 tty_insert_flip_char(port, 0, TTY_OVERRUN);
1180 if (bits & 4)
1181 tty_insert_flip_char(port, 0, TTY_PARITY);
1182 if (bits & 8)
1183 tty_insert_flip_char(port, 0, TTY_FRAME);
1184
1185 tty_flip_buffer_push(port);
1186
1187 gsm_control_reply(gsm, CMD_RLS, data, clen);
1188}
1189
1190static void gsm_dlci_begin_close(struct gsm_dlci *dlci);
1191
1192/**
1193 * gsm_control_message - DLCI 0 control processing
1194 * @gsm: our GSM mux
1195 * @command: the command EA
1196 * @data: data beyond the command/length EAs
1197 * @clen: length
1198 *
1199 * Input processor for control messages from the other end of the link.
1200 * Processes the incoming request and queues a response frame or an
1201 * NSC response if not supported
1202 */
1203
1204static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
1205 u8 *data, int clen)
1206{
1207 u8 buf[1];
1208 unsigned long flags;
1209
1210 switch (command) {
1211 case CMD_CLD: {
1212 struct gsm_dlci *dlci = gsm->dlci[0];
1213 /* Modem wishes to close down */
1214 if (dlci) {
1215 dlci->dead = 1;
1216 gsm->dead = 1;
1217 gsm_dlci_begin_close(dlci);
1218 }
1219 }
1220 break;
1221 case CMD_TEST:
1222 /* Modem wishes to test, reply with the data */
1223 gsm_control_reply(gsm, CMD_TEST, data, clen);
1224 break;
1225 case CMD_FCON:
1226 /* Modem can accept data again */
1227 gsm->constipated = 0;
1228 gsm_control_reply(gsm, CMD_FCON, NULL, 0);
1229 /* Kick the link in case it is idling */
1230 spin_lock_irqsave(&gsm->tx_lock, flags);
1231 gsm_data_kick(gsm);
1232 spin_unlock_irqrestore(&gsm->tx_lock, flags);
1233 break;
1234 case CMD_FCOFF:
1235 /* Modem wants us to STFU */
1236 gsm->constipated = 1;
1237 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0);
1238 break;
1239 case CMD_MSC:
1240 /* Out of band modem line change indicator for a DLCI */
1241 gsm_control_modem(gsm, data, clen);
1242 break;
1243 case CMD_RLS:
1244 /* Out of band error reception for a DLCI */
1245 gsm_control_rls(gsm, data, clen);
1246 break;
1247 case CMD_PSC:
1248 /* Modem wishes to enter power saving state */
1249 gsm_control_reply(gsm, CMD_PSC, NULL, 0);
1250 break;
1251 /* Optional unsupported commands */
1252 case CMD_PN: /* Parameter negotiation */
1253 case CMD_RPN: /* Remote port negotiation */
1254 case CMD_SNC: /* Service negotiation command */
1255 default:
1256 /* Reply to bad commands with an NSC */
1257 buf[0] = command;
1258 gsm_control_reply(gsm, CMD_NSC, buf, 1);
1259 break;
1260 }
1261}
1262
1263/**
1264 * gsm_control_response - process a response to our control
1265 * @gsm: our GSM mux
1266 * @command: the command (response) EA
1267 * @data: data beyond the command/length EA
1268 * @clen: length
1269 *
1270 * Process a response to an outstanding command. We only allow a single
1271 * control message in flight so this is fairly easy. All the clean up
1272 * is done by the caller, we just update the fields, flag it as done
1273 * and return
1274 */
1275
1276static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
1277 u8 *data, int clen)
1278{
1279 struct gsm_control *ctrl;
1280 unsigned long flags;
1281
1282 spin_lock_irqsave(&gsm->control_lock, flags);
1283
1284 ctrl = gsm->pending_cmd;
1285 /* Does the reply match our command */
1286 command |= 1;
1287 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) {
1288 /* Our command was replied to, kill the retry timer */
1289 del_timer(&gsm->t2_timer);
1290 gsm->pending_cmd = NULL;
1291 /* Rejected by the other end */
1292 if (command == CMD_NSC)
1293 ctrl->error = -EOPNOTSUPP;
1294 ctrl->done = 1;
1295 wake_up(&gsm->event);
1296 }
1297 spin_unlock_irqrestore(&gsm->control_lock, flags);
1298}
1299
1300/**
1301 * gsm_control_transmit - send control packet
1302 * @gsm: gsm mux
1303 * @ctrl: frame to send
1304 *
1305 * Send out a pending control command (called under control lock)
1306 */
1307
1308static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl)
1309{
1310 struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, gsm->ftype);
1311 if (msg == NULL)
1312 return;
1313 msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */
1314 memcpy(msg->data + 1, ctrl->data, ctrl->len);
1315 gsm_data_queue(gsm->dlci[0], msg);
1316}
1317
1318/**
1319 * gsm_control_retransmit - retransmit a control frame
1320 * @data: pointer to our gsm object
1321 *
1322 * Called off the T2 timer expiry in order to retransmit control frames
1323 * that have been lost in the system somewhere. The control_lock protects
1324 * us from colliding with another sender or a receive completion event.
1325 * In that situation the timer may still occur in a small window but
1326 * gsm->pending_cmd will be NULL and we just let the timer expire.
1327 */
1328
1329static void gsm_control_retransmit(unsigned long data)
1330{
1331 struct gsm_mux *gsm = (struct gsm_mux *)data;
1332 struct gsm_control *ctrl;
1333 unsigned long flags;
1334 spin_lock_irqsave(&gsm->control_lock, flags);
1335 ctrl = gsm->pending_cmd;
1336 if (ctrl) {
1337 gsm->cretries--;
1338 if (gsm->cretries == 0) {
1339 gsm->pending_cmd = NULL;
1340 ctrl->error = -ETIMEDOUT;
1341 ctrl->done = 1;
1342 spin_unlock_irqrestore(&gsm->control_lock, flags);
1343 wake_up(&gsm->event);
1344 return;
1345 }
1346 gsm_control_transmit(gsm, ctrl);
1347 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1348 }
1349 spin_unlock_irqrestore(&gsm->control_lock, flags);
1350}
1351
1352/**
1353 * gsm_control_send - send a control frame on DLCI 0
1354 * @gsm: the GSM channel
1355 * @command: command to send including CR bit
1356 * @data: bytes of data (must be kmalloced)
1357 * @len: length of the block to send
1358 *
1359 * Queue and dispatch a control command. Only one command can be
1360 * active at a time. In theory more can be outstanding but the matching
1361 * gets really complicated so for now stick to one outstanding.
1362 */
1363
1364static struct gsm_control *gsm_control_send(struct gsm_mux *gsm,
1365 unsigned int command, u8 *data, int clen)
1366{
1367 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control),
1368 GFP_KERNEL);
1369 unsigned long flags;
1370 if (ctrl == NULL)
1371 return NULL;
1372retry:
1373 wait_event(gsm->event, gsm->pending_cmd == NULL);
1374 spin_lock_irqsave(&gsm->control_lock, flags);
1375 if (gsm->pending_cmd != NULL) {
1376 spin_unlock_irqrestore(&gsm->control_lock, flags);
1377 goto retry;
1378 }
1379 ctrl->cmd = command;
1380 ctrl->data = data;
1381 ctrl->len = clen;
1382 gsm->pending_cmd = ctrl;
1383 gsm->cretries = gsm->n2;
1384 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1385 gsm_control_transmit(gsm, ctrl);
1386 spin_unlock_irqrestore(&gsm->control_lock, flags);
1387 return ctrl;
1388}
1389
1390/**
1391 * gsm_control_wait - wait for a control to finish
1392 * @gsm: GSM mux
1393 * @control: control we are waiting on
1394 *
1395 * Waits for the control to complete or time out. Frees any used
1396 * resources and returns 0 for success, or an error if the remote
1397 * rejected or ignored the request.
1398 */
1399
1400static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
1401{
1402 int err;
1403 wait_event(gsm->event, control->done == 1);
1404 err = control->error;
1405 kfree(control);
1406 return err;
1407}
1408
1409
1410/*
1411 * DLCI level handling: Needs krefs
1412 */
1413
1414/*
1415 * State transitions and timers
1416 */
1417
1418/**
1419 * gsm_dlci_close - a DLCI has closed
1420 * @dlci: DLCI that closed
1421 *
1422 * Perform processing when moving a DLCI into closed state. If there
1423 * is an attached tty this is hung up
1424 */
1425
1426static void gsm_dlci_close(struct gsm_dlci *dlci)
1427{
1428 del_timer(&dlci->t1);
1429 if (debug & 8)
1430 pr_debug("DLCI %d goes closed.\n", dlci->addr);
1431 dlci->state = DLCI_CLOSED;
1432 if (dlci->addr != 0) {
1433 tty_port_tty_hangup(&dlci->port, false);
1434 kfifo_reset(dlci->fifo);
1435 } else
1436 dlci->gsm->dead = 1;
1437 wake_up(&dlci->gsm->event);
1438 /* A DLCI 0 close is a MUX termination so we need to kick that
1439 back to userspace somehow */
1440}
1441
1442/**
1443 * gsm_dlci_open - a DLCI has opened
1444 * @dlci: DLCI that opened
1445 *
1446 * Perform processing when moving a DLCI into open state.
1447 */
1448
1449static void gsm_dlci_open(struct gsm_dlci *dlci)
1450{
1451 /* Note that SABM UA .. SABM UA first UA lost can mean that we go
1452 open -> open */
1453 del_timer(&dlci->t1);
1454 /* This will let a tty open continue */
1455 dlci->state = DLCI_OPEN;
1456 if (debug & 8)
1457 pr_debug("DLCI %d goes open.\n", dlci->addr);
1458 wake_up(&dlci->gsm->event);
1459}
1460
1461/**
1462 * gsm_dlci_t1 - T1 timer expiry
1463 * @dlci: DLCI that opened
1464 *
1465 * The T1 timer handles retransmits of control frames (essentially of
1466 * SABM and DISC). We resend the command until the retry count runs out
1467 * in which case an opening port goes back to closed and a closing port
1468 * is simply put into closed state (any further frames from the other
1469 * end will get a DM response)
1470 */
1471
1472static void gsm_dlci_t1(unsigned long data)
1473{
1474 struct gsm_dlci *dlci = (struct gsm_dlci *)data;
1475 struct gsm_mux *gsm = dlci->gsm;
1476
1477 switch (dlci->state) {
1478 case DLCI_OPENING:
1479 dlci->retries--;
1480 if (dlci->retries) {
1481 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1482 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1483 } else
1484 gsm_dlci_close(dlci);
1485 break;
1486 case DLCI_CLOSING:
1487 dlci->retries--;
1488 if (dlci->retries) {
1489 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1490 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1491 } else
1492 gsm_dlci_close(dlci);
1493 break;
1494 }
1495}
1496
1497/**
1498 * gsm_dlci_begin_open - start channel open procedure
1499 * @dlci: DLCI to open
1500 *
1501 * Commence opening a DLCI from the Linux side. We issue SABM messages
1502 * to the modem which should then reply with a UA, at which point we
1503 * will move into open state. Opening is done asynchronously with retry
1504 * running off timers and the responses.
1505 */
1506
1507static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
1508{
1509 struct gsm_mux *gsm = dlci->gsm;
1510 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING)
1511 return;
1512 dlci->retries = gsm->n2;
1513 dlci->state = DLCI_OPENING;
1514 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1515 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1516}
1517
1518/**
1519 * gsm_dlci_begin_close - start channel open procedure
1520 * @dlci: DLCI to open
1521 *
1522 * Commence closing a DLCI from the Linux side. We issue DISC messages
1523 * to the modem which should then reply with a UA, at which point we
1524 * will move into closed state. Closing is done asynchronously with retry
1525 * off timers. We may also receive a DM reply from the other end which
1526 * indicates the channel was already closed.
1527 */
1528
1529static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
1530{
1531 struct gsm_mux *gsm = dlci->gsm;
1532 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
1533 return;
1534 dlci->retries = gsm->n2;
1535 dlci->state = DLCI_CLOSING;
1536 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1537 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1538}
1539
1540/**
1541 * gsm_dlci_data - data arrived
1542 * @dlci: channel
1543 * @data: block of bytes received
1544 * @len: length of received block
1545 *
1546 * A UI or UIH frame has arrived which contains data for a channel
1547 * other than the control channel. If the relevant virtual tty is
1548 * open we shovel the bits down it, if not we drop them.
1549 */
1550
1551static void gsm_dlci_data(struct gsm_dlci *dlci, u8 *data, int clen)
1552{
1553 /* krefs .. */
1554 struct tty_port *port = &dlci->port;
1555 struct tty_struct *tty;
1556 unsigned int modem = 0;
1557 int len = clen;
1558
1559 if (debug & 16)
1560 pr_debug("%d bytes for tty\n", len);
1561 switch (dlci->adaption) {
1562 /* Unsupported types */
1563 /* Packetised interruptible data */
1564 case 4:
1565 break;
1566 /* Packetised uininterruptible voice/data */
1567 case 3:
1568 break;
1569 /* Asynchronous serial with line state in each frame */
1570 case 2:
1571 while (gsm_read_ea(&modem, *data++) == 0) {
1572 len--;
1573 if (len == 0)
1574 return;
1575 }
1576 tty = tty_port_tty_get(port);
1577 if (tty) {
1578 gsm_process_modem(tty, dlci, modem, clen);
1579 tty_kref_put(tty);
1580 }
1581 /* Line state will go via DLCI 0 controls only */
1582 case 1:
1583 default:
1584 tty_insert_flip_string(port, data, len);
1585 tty_flip_buffer_push(port);
1586 }
1587}
1588
1589/**
1590 * gsm_dlci_control - data arrived on control channel
1591 * @dlci: channel
1592 * @data: block of bytes received
1593 * @len: length of received block
1594 *
1595 * A UI or UIH frame has arrived which contains data for DLCI 0 the
1596 * control channel. This should contain a command EA followed by
1597 * control data bytes. The command EA contains a command/response bit
1598 * and we divide up the work accordingly.
1599 */
1600
1601static void gsm_dlci_command(struct gsm_dlci *dlci, u8 *data, int len)
1602{
1603 /* See what command is involved */
1604 unsigned int command = 0;
1605 while (len-- > 0) {
1606 if (gsm_read_ea(&command, *data++) == 1) {
1607 int clen = *data++;
1608 len--;
1609 /* FIXME: this is properly an EA */
1610 clen >>= 1;
1611 /* Malformed command ? */
1612 if (clen > len)
1613 return;
1614 if (command & 1)
1615 gsm_control_message(dlci->gsm, command,
1616 data, clen);
1617 else
1618 gsm_control_response(dlci->gsm, command,
1619 data, clen);
1620 return;
1621 }
1622 }
1623}
1624
1625/*
1626 * Allocate/Free DLCI channels
1627 */
1628
1629/**
1630 * gsm_dlci_alloc - allocate a DLCI
1631 * @gsm: GSM mux
1632 * @addr: address of the DLCI
1633 *
1634 * Allocate and install a new DLCI object into the GSM mux.
1635 *
1636 * FIXME: review locking races
1637 */
1638
1639static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
1640{
1641 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC);
1642 if (dlci == NULL)
1643 return NULL;
1644 spin_lock_init(&dlci->lock);
1645 mutex_init(&dlci->mutex);
1646 dlci->fifo = &dlci->_fifo;
1647 if (kfifo_alloc(&dlci->_fifo, 4096, GFP_KERNEL) < 0) {
1648 kfree(dlci);
1649 return NULL;
1650 }
1651
1652 skb_queue_head_init(&dlci->skb_list);
1653 init_timer(&dlci->t1);
1654 dlci->t1.function = gsm_dlci_t1;
1655 dlci->t1.data = (unsigned long)dlci;
1656 tty_port_init(&dlci->port);
1657 dlci->port.ops = &gsm_port_ops;
1658 dlci->gsm = gsm;
1659 dlci->addr = addr;
1660 dlci->adaption = gsm->adaption;
1661 dlci->state = DLCI_CLOSED;
1662 if (addr)
1663 dlci->data = gsm_dlci_data;
1664 else
1665 dlci->data = gsm_dlci_command;
1666 gsm->dlci[addr] = dlci;
1667 return dlci;
1668}
1669
1670/**
1671 * gsm_dlci_free - free DLCI
1672 * @dlci: DLCI to free
1673 *
1674 * Free up a DLCI.
1675 *
1676 * Can sleep.
1677 */
1678static void gsm_dlci_free(struct tty_port *port)
1679{
1680 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
1681
1682 del_timer_sync(&dlci->t1);
1683 dlci->gsm->dlci[dlci->addr] = NULL;
1684 kfifo_free(dlci->fifo);
1685 while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
1686 dev_kfree_skb(dlci->skb);
1687 kfree(dlci);
1688}
1689
1690static inline void dlci_get(struct gsm_dlci *dlci)
1691{
1692 tty_port_get(&dlci->port);
1693}
1694
1695static inline void dlci_put(struct gsm_dlci *dlci)
1696{
1697 tty_port_put(&dlci->port);
1698}
1699
1700static void gsm_destroy_network(struct gsm_dlci *dlci);
1701
1702/**
1703 * gsm_dlci_release - release DLCI
1704 * @dlci: DLCI to destroy
1705 *
1706 * Release a DLCI. Actual free is deferred until either
1707 * mux is closed or tty is closed - whichever is last.
1708 *
1709 * Can sleep.
1710 */
1711static void gsm_dlci_release(struct gsm_dlci *dlci)
1712{
1713 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1714 if (tty) {
1715 mutex_lock(&dlci->mutex);
1716 gsm_destroy_network(dlci);
1717 mutex_unlock(&dlci->mutex);
1718
1719 tty_vhangup(tty);
1720
1721 tty_port_tty_set(&dlci->port, NULL);
1722 tty_kref_put(tty);
1723 }
1724 dlci->state = DLCI_CLOSED;
1725 dlci_put(dlci);
1726}
1727
1728/*
1729 * LAPBish link layer logic
1730 */
1731
1732/**
1733 * gsm_queue - a GSM frame is ready to process
1734 * @gsm: pointer to our gsm mux
1735 *
1736 * At this point in time a frame has arrived and been demangled from
1737 * the line encoding. All the differences between the encodings have
1738 * been handled below us and the frame is unpacked into the structures.
1739 * The fcs holds the header FCS but any data FCS must be added here.
1740 */
1741
1742static void gsm_queue(struct gsm_mux *gsm)
1743{
1744 struct gsm_dlci *dlci;
1745 u8 cr;
1746 int address;
1747 /* We have to sneak a look at the packet body to do the FCS.
1748 A somewhat layering violation in the spec */
1749
1750 if ((gsm->control & ~PF) == UI)
1751 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len);
1752 if (gsm->encoding == 0) {
1753 /* WARNING: gsm->received_fcs is used for
1754 gsm->encoding = 0 only.
1755 In this case it contain the last piece of data
1756 required to generate final CRC */
1757 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs);
1758 }
1759 if (gsm->fcs != GOOD_FCS) {
1760 gsm->bad_fcs++;
1761 if (debug & 4)
1762 pr_debug("BAD FCS %02x\n", gsm->fcs);
1763 return;
1764 }
1765 address = gsm->address >> 1;
1766 if (address >= NUM_DLCI)
1767 goto invalid;
1768
1769 cr = gsm->address & 1; /* C/R bit */
1770
1771 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
1772
1773 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */
1774 dlci = gsm->dlci[address];
1775
1776 switch (gsm->control) {
1777 case SABM|PF:
1778 if (cr == 0)
1779 goto invalid;
1780 if (dlci == NULL)
1781 dlci = gsm_dlci_alloc(gsm, address);
1782 if (dlci == NULL)
1783 return;
1784 if (dlci->dead)
1785 gsm_response(gsm, address, DM);
1786 else {
1787 gsm_response(gsm, address, UA);
1788 gsm_dlci_open(dlci);
1789 }
1790 break;
1791 case DISC|PF:
1792 if (cr == 0)
1793 goto invalid;
1794 if (dlci == NULL || dlci->state == DLCI_CLOSED) {
1795 gsm_response(gsm, address, DM);
1796 return;
1797 }
1798 /* Real close complete */
1799 gsm_response(gsm, address, UA);
1800 gsm_dlci_close(dlci);
1801 break;
1802 case UA:
1803 case UA|PF:
1804 if (cr == 0 || dlci == NULL)
1805 break;
1806 switch (dlci->state) {
1807 case DLCI_CLOSING:
1808 gsm_dlci_close(dlci);
1809 break;
1810 case DLCI_OPENING:
1811 gsm_dlci_open(dlci);
1812 break;
1813 }
1814 break;
1815 case DM: /* DM can be valid unsolicited */
1816 case DM|PF:
1817 if (cr)
1818 goto invalid;
1819 if (dlci == NULL)
1820 return;
1821 gsm_dlci_close(dlci);
1822 break;
1823 case UI:
1824 case UI|PF:
1825 case UIH:
1826 case UIH|PF:
1827#if 0
1828 if (cr)
1829 goto invalid;
1830#endif
1831 if (dlci == NULL || dlci->state != DLCI_OPEN) {
1832 gsm_command(gsm, address, DM|PF);
1833 return;
1834 }
1835 dlci->data(dlci, gsm->buf, gsm->len);
1836 break;
1837 default:
1838 goto invalid;
1839 }
1840 return;
1841invalid:
1842 gsm->malformed++;
1843 return;
1844}
1845
1846
1847/**
1848 * gsm0_receive - perform processing for non-transparency
1849 * @gsm: gsm data for this ldisc instance
1850 * @c: character
1851 *
1852 * Receive bytes in gsm mode 0
1853 */
1854
1855static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
1856{
1857 unsigned int len;
1858
1859 switch (gsm->state) {
1860 case GSM_SEARCH: /* SOF marker */
1861 if (c == GSM0_SOF) {
1862 gsm->state = GSM_ADDRESS;
1863 gsm->address = 0;
1864 gsm->len = 0;
1865 gsm->fcs = INIT_FCS;
1866 }
1867 break;
1868 case GSM_ADDRESS: /* Address EA */
1869 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1870 if (gsm_read_ea(&gsm->address, c))
1871 gsm->state = GSM_CONTROL;
1872 break;
1873 case GSM_CONTROL: /* Control Byte */
1874 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1875 gsm->control = c;
1876 gsm->state = GSM_LEN0;
1877 break;
1878 case GSM_LEN0: /* Length EA */
1879 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1880 if (gsm_read_ea(&gsm->len, c)) {
1881 if (gsm->len > gsm->mru) {
1882 gsm->bad_size++;
1883 gsm->state = GSM_SEARCH;
1884 break;
1885 }
1886 gsm->count = 0;
1887 if (!gsm->len)
1888 gsm->state = GSM_FCS;
1889 else
1890 gsm->state = GSM_DATA;
1891 break;
1892 }
1893 gsm->state = GSM_LEN1;
1894 break;
1895 case GSM_LEN1:
1896 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1897 len = c;
1898 gsm->len |= len << 7;
1899 if (gsm->len > gsm->mru) {
1900 gsm->bad_size++;
1901 gsm->state = GSM_SEARCH;
1902 break;
1903 }
1904 gsm->count = 0;
1905 if (!gsm->len)
1906 gsm->state = GSM_FCS;
1907 else
1908 gsm->state = GSM_DATA;
1909 break;
1910 case GSM_DATA: /* Data */
1911 gsm->buf[gsm->count++] = c;
1912 if (gsm->count == gsm->len)
1913 gsm->state = GSM_FCS;
1914 break;
1915 case GSM_FCS: /* FCS follows the packet */
1916 gsm->received_fcs = c;
1917 gsm_queue(gsm);
1918 gsm->state = GSM_SSOF;
1919 break;
1920 case GSM_SSOF:
1921 if (c == GSM0_SOF) {
1922 gsm->state = GSM_SEARCH;
1923 break;
1924 }
1925 break;
1926 }
1927}
1928
1929/**
1930 * gsm1_receive - perform processing for non-transparency
1931 * @gsm: gsm data for this ldisc instance
1932 * @c: character
1933 *
1934 * Receive bytes in mode 1 (Advanced option)
1935 */
1936
1937static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
1938{
1939 if (c == GSM1_SOF) {
1940 /* EOF is only valid in frame if we have got to the data state
1941 and received at least one byte (the FCS) */
1942 if (gsm->state == GSM_DATA && gsm->count) {
1943 /* Extract the FCS */
1944 gsm->count--;
1945 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
1946 gsm->len = gsm->count;
1947 gsm_queue(gsm);
1948 gsm->state = GSM_START;
1949 return;
1950 }
1951 /* Any partial frame was a runt so go back to start */
1952 if (gsm->state != GSM_START) {
1953 gsm->malformed++;
1954 gsm->state = GSM_START;
1955 }
1956 /* A SOF in GSM_START means we are still reading idling or
1957 framing bytes */
1958 return;
1959 }
1960
1961 if (c == GSM1_ESCAPE) {
1962 gsm->escape = 1;
1963 return;
1964 }
1965
1966 /* Only an unescaped SOF gets us out of GSM search */
1967 if (gsm->state == GSM_SEARCH)
1968 return;
1969
1970 if (gsm->escape) {
1971 c ^= GSM1_ESCAPE_BITS;
1972 gsm->escape = 0;
1973 }
1974 switch (gsm->state) {
1975 case GSM_START: /* First byte after SOF */
1976 gsm->address = 0;
1977 gsm->state = GSM_ADDRESS;
1978 gsm->fcs = INIT_FCS;
1979 /* Drop through */
1980 case GSM_ADDRESS: /* Address continuation */
1981 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1982 if (gsm_read_ea(&gsm->address, c))
1983 gsm->state = GSM_CONTROL;
1984 break;
1985 case GSM_CONTROL: /* Control Byte */
1986 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1987 gsm->control = c;
1988 gsm->count = 0;
1989 gsm->state = GSM_DATA;
1990 break;
1991 case GSM_DATA: /* Data */
1992 if (gsm->count > gsm->mru) { /* Allow one for the FCS */
1993 gsm->state = GSM_OVERRUN;
1994 gsm->bad_size++;
1995 } else
1996 gsm->buf[gsm->count++] = c;
1997 break;
1998 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */
1999 break;
2000 }
2001}
2002
2003/**
2004 * gsm_error - handle tty error
2005 * @gsm: ldisc data
2006 * @data: byte received (may be invalid)
2007 * @flag: error received
2008 *
2009 * Handle an error in the receipt of data for a frame. Currently we just
2010 * go back to hunting for a SOF.
2011 *
2012 * FIXME: better diagnostics ?
2013 */
2014
2015static void gsm_error(struct gsm_mux *gsm,
2016 unsigned char data, unsigned char flag)
2017{
2018 gsm->state = GSM_SEARCH;
2019 gsm->io_error++;
2020}
2021
2022/**
2023 * gsm_cleanup_mux - generic GSM protocol cleanup
2024 * @gsm: our mux
2025 *
2026 * Clean up the bits of the mux which are the same for all framing
2027 * protocols. Remove the mux from the mux table, stop all the timers
2028 * and then shut down each device hanging up the channels as we go.
2029 */
2030
2031static void gsm_cleanup_mux(struct gsm_mux *gsm)
2032{
2033 int i;
2034 struct gsm_dlci *dlci = gsm->dlci[0];
2035 struct gsm_msg *txq, *ntxq;
2036 struct gsm_control *gc;
2037
2038 gsm->dead = 1;
2039
2040 spin_lock(&gsm_mux_lock);
2041 for (i = 0; i < MAX_MUX; i++) {
2042 if (gsm_mux[i] == gsm) {
2043 gsm_mux[i] = NULL;
2044 break;
2045 }
2046 }
2047 spin_unlock(&gsm_mux_lock);
2048 /* open failed before registering => nothing to do */
2049 if (i == MAX_MUX)
2050 return;
2051
2052 /* In theory disconnecting DLCI 0 is sufficient but for some
2053 modems this is apparently not the case. */
2054 if (dlci) {
2055 gc = gsm_control_send(gsm, CMD_CLD, NULL, 0);
2056 if (gc)
2057 gsm_control_wait(gsm, gc);
2058 }
2059 del_timer_sync(&gsm->t2_timer);
2060 /* Now we are sure T2 has stopped */
2061 if (dlci) {
2062 dlci->dead = 1;
2063 gsm_dlci_begin_close(dlci);
2064 wait_event_interruptible(gsm->event,
2065 dlci->state == DLCI_CLOSED);
2066 }
2067 /* Free up any link layer users */
2068 mutex_lock(&gsm->mutex);
2069 for (i = 0; i < NUM_DLCI; i++)
2070 if (gsm->dlci[i])
2071 gsm_dlci_release(gsm->dlci[i]);
2072 mutex_unlock(&gsm->mutex);
2073 /* Now wipe the queues */
2074 list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list)
2075 kfree(txq);
2076 INIT_LIST_HEAD(&gsm->tx_list);
2077}
2078
2079/**
2080 * gsm_activate_mux - generic GSM setup
2081 * @gsm: our mux
2082 *
2083 * Set up the bits of the mux which are the same for all framing
2084 * protocols. Add the mux to the mux table so it can be opened and
2085 * finally kick off connecting to DLCI 0 on the modem.
2086 */
2087
2088static int gsm_activate_mux(struct gsm_mux *gsm)
2089{
2090 struct gsm_dlci *dlci;
2091 int i = 0;
2092
2093 setup_timer(&gsm->t2_timer, gsm_control_retransmit, (unsigned long)gsm);
2094 init_waitqueue_head(&gsm->event);
2095 spin_lock_init(&gsm->control_lock);
2096 spin_lock_init(&gsm->tx_lock);
2097
2098 if (gsm->encoding == 0)
2099 gsm->receive = gsm0_receive;
2100 else
2101 gsm->receive = gsm1_receive;
2102 gsm->error = gsm_error;
2103
2104 spin_lock(&gsm_mux_lock);
2105 for (i = 0; i < MAX_MUX; i++) {
2106 if (gsm_mux[i] == NULL) {
2107 gsm->num = i;
2108 gsm_mux[i] = gsm;
2109 break;
2110 }
2111 }
2112 spin_unlock(&gsm_mux_lock);
2113 if (i == MAX_MUX)
2114 return -EBUSY;
2115
2116 dlci = gsm_dlci_alloc(gsm, 0);
2117 if (dlci == NULL)
2118 return -ENOMEM;
2119 gsm->dead = 0; /* Tty opens are now permissible */
2120 return 0;
2121}
2122
2123/**
2124 * gsm_free_mux - free up a mux
2125 * @mux: mux to free
2126 *
2127 * Dispose of allocated resources for a dead mux
2128 */
2129static void gsm_free_mux(struct gsm_mux *gsm)
2130{
2131 kfree(gsm->txframe);
2132 kfree(gsm->buf);
2133 kfree(gsm);
2134}
2135
2136/**
2137 * gsm_free_muxr - free up a mux
2138 * @mux: mux to free
2139 *
2140 * Dispose of allocated resources for a dead mux
2141 */
2142static void gsm_free_muxr(struct kref *ref)
2143{
2144 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref);
2145 gsm_free_mux(gsm);
2146}
2147
2148static inline void mux_get(struct gsm_mux *gsm)
2149{
2150 kref_get(&gsm->ref);
2151}
2152
2153static inline void mux_put(struct gsm_mux *gsm)
2154{
2155 kref_put(&gsm->ref, gsm_free_muxr);
2156}
2157
2158/**
2159 * gsm_alloc_mux - allocate a mux
2160 *
2161 * Creates a new mux ready for activation.
2162 */
2163
2164static struct gsm_mux *gsm_alloc_mux(void)
2165{
2166 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
2167 if (gsm == NULL)
2168 return NULL;
2169 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL);
2170 if (gsm->buf == NULL) {
2171 kfree(gsm);
2172 return NULL;
2173 }
2174 gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL);
2175 if (gsm->txframe == NULL) {
2176 kfree(gsm->buf);
2177 kfree(gsm);
2178 return NULL;
2179 }
2180 spin_lock_init(&gsm->lock);
2181 mutex_init(&gsm->mutex);
2182 kref_init(&gsm->ref);
2183 INIT_LIST_HEAD(&gsm->tx_list);
2184
2185 gsm->t1 = T1;
2186 gsm->t2 = T2;
2187 gsm->n2 = N2;
2188 gsm->ftype = UIH;
2189 gsm->adaption = 1;
2190 gsm->encoding = 1;
2191 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
2192 gsm->mtu = 64;
2193 gsm->dead = 1; /* Avoid early tty opens */
2194
2195 return gsm;
2196}
2197
2198/**
2199 * gsmld_output - write to link
2200 * @gsm: our mux
2201 * @data: bytes to output
2202 * @len: size
2203 *
2204 * Write a block of data from the GSM mux to the data channel. This
2205 * will eventually be serialized from above but at the moment isn't.
2206 */
2207
2208static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
2209{
2210 if (tty_write_room(gsm->tty) < len) {
2211 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
2212 return -ENOSPC;
2213 }
2214 if (debug & 4)
2215 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET,
2216 data, len);
2217 gsm->tty->ops->write(gsm->tty, data, len);
2218 return len;
2219}
2220
2221/**
2222 * gsmld_attach_gsm - mode set up
2223 * @tty: our tty structure
2224 * @gsm: our mux
2225 *
2226 * Set up the MUX for basic mode and commence connecting to the
2227 * modem. Currently called from the line discipline set up but
2228 * will need moving to an ioctl path.
2229 */
2230
2231static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2232{
2233 int ret, i, base;
2234
2235 gsm->tty = tty_kref_get(tty);
2236 gsm->output = gsmld_output;
2237 ret = gsm_activate_mux(gsm);
2238 if (ret != 0)
2239 tty_kref_put(gsm->tty);
2240 else {
2241 /* Don't register device 0 - this is the control channel and not
2242 a usable tty interface */
2243 base = gsm->num << 6; /* Base for this MUX */
2244 for (i = 1; i < NUM_DLCI; i++)
2245 tty_register_device(gsm_tty_driver, base + i, NULL);
2246 }
2247 return ret;
2248}
2249
2250
2251/**
2252 * gsmld_detach_gsm - stop doing 0710 mux
2253 * @tty: tty attached to the mux
2254 * @gsm: mux
2255 *
2256 * Shutdown and then clean up the resources used by the line discipline
2257 */
2258
2259static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2260{
2261 int i;
2262 int base = gsm->num << 6; /* Base for this MUX */
2263
2264 WARN_ON(tty != gsm->tty);
2265 for (i = 1; i < NUM_DLCI; i++)
2266 tty_unregister_device(gsm_tty_driver, base + i);
2267 gsm_cleanup_mux(gsm);
2268 tty_kref_put(gsm->tty);
2269 gsm->tty = NULL;
2270}
2271
2272static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
2273 char *fp, int count)
2274{
2275 struct gsm_mux *gsm = tty->disc_data;
2276 const unsigned char *dp;
2277 char *f;
2278 int i;
2279 char flags = TTY_NORMAL;
2280
2281 if (debug & 4)
2282 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET,
2283 cp, count);
2284
2285 for (i = count, dp = cp, f = fp; i; i--, dp++) {
2286 if (f)
2287 flags = *f++;
2288 switch (flags) {
2289 case TTY_NORMAL:
2290 gsm->receive(gsm, *dp);
2291 break;
2292 case TTY_OVERRUN:
2293 case TTY_BREAK:
2294 case TTY_PARITY:
2295 case TTY_FRAME:
2296 gsm->error(gsm, *dp, flags);
2297 break;
2298 default:
2299 WARN_ONCE(1, "%s: unknown flag %d\n",
2300 tty_name(tty), flags);
2301 break;
2302 }
2303 }
2304 /* FASYNC if needed ? */
2305 /* If clogged call tty_throttle(tty); */
2306}
2307
2308/**
2309 * gsmld_flush_buffer - clean input queue
2310 * @tty: terminal device
2311 *
2312 * Flush the input buffer. Called when the line discipline is
2313 * being closed, when the tty layer wants the buffer flushed (eg
2314 * at hangup).
2315 */
2316
2317static void gsmld_flush_buffer(struct tty_struct *tty)
2318{
2319}
2320
2321/**
2322 * gsmld_close - close the ldisc for this tty
2323 * @tty: device
2324 *
2325 * Called from the terminal layer when this line discipline is
2326 * being shut down, either because of a close or becsuse of a
2327 * discipline change. The function will not be called while other
2328 * ldisc methods are in progress.
2329 */
2330
2331static void gsmld_close(struct tty_struct *tty)
2332{
2333 struct gsm_mux *gsm = tty->disc_data;
2334
2335 gsmld_detach_gsm(tty, gsm);
2336
2337 gsmld_flush_buffer(tty);
2338 /* Do other clean up here */
2339 mux_put(gsm);
2340}
2341
2342/**
2343 * gsmld_open - open an ldisc
2344 * @tty: terminal to open
2345 *
2346 * Called when this line discipline is being attached to the
2347 * terminal device. Can sleep. Called serialized so that no
2348 * other events will occur in parallel. No further open will occur
2349 * until a close.
2350 */
2351
2352static int gsmld_open(struct tty_struct *tty)
2353{
2354 struct gsm_mux *gsm;
2355 int ret;
2356
2357 if (tty->ops->write == NULL)
2358 return -EINVAL;
2359
2360 /* Attach our ldisc data */
2361 gsm = gsm_alloc_mux();
2362 if (gsm == NULL)
2363 return -ENOMEM;
2364
2365 tty->disc_data = gsm;
2366 tty->receive_room = 65536;
2367
2368 /* Attach the initial passive connection */
2369 gsm->encoding = 1;
2370
2371 ret = gsmld_attach_gsm(tty, gsm);
2372 if (ret != 0) {
2373 gsm_cleanup_mux(gsm);
2374 mux_put(gsm);
2375 }
2376 return ret;
2377}
2378
2379/**
2380 * gsmld_write_wakeup - asynchronous I/O notifier
2381 * @tty: tty device
2382 *
2383 * Required for the ptys, serial driver etc. since processes
2384 * that attach themselves to the master and rely on ASYNC
2385 * IO must be woken up
2386 */
2387
2388static void gsmld_write_wakeup(struct tty_struct *tty)
2389{
2390 struct gsm_mux *gsm = tty->disc_data;
2391 unsigned long flags;
2392
2393 /* Queue poll */
2394 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2395 spin_lock_irqsave(&gsm->tx_lock, flags);
2396 gsm_data_kick(gsm);
2397 if (gsm->tx_bytes < TX_THRESH_LO) {
2398 gsm_dlci_data_sweep(gsm);
2399 }
2400 spin_unlock_irqrestore(&gsm->tx_lock, flags);
2401}
2402
2403/**
2404 * gsmld_read - read function for tty
2405 * @tty: tty device
2406 * @file: file object
2407 * @buf: userspace buffer pointer
2408 * @nr: size of I/O
2409 *
2410 * Perform reads for the line discipline. We are guaranteed that the
2411 * line discipline will not be closed under us but we may get multiple
2412 * parallel readers and must handle this ourselves. We may also get
2413 * a hangup. Always called in user context, may sleep.
2414 *
2415 * This code must be sure never to sleep through a hangup.
2416 */
2417
2418static ssize_t gsmld_read(struct tty_struct *tty, struct file *file,
2419 unsigned char __user *buf, size_t nr)
2420{
2421 return -EOPNOTSUPP;
2422}
2423
2424/**
2425 * gsmld_write - write function for tty
2426 * @tty: tty device
2427 * @file: file object
2428 * @buf: userspace buffer pointer
2429 * @nr: size of I/O
2430 *
2431 * Called when the owner of the device wants to send a frame
2432 * itself (or some other control data). The data is transferred
2433 * as-is and must be properly framed and checksummed as appropriate
2434 * by userspace. Frames are either sent whole or not at all as this
2435 * avoids pain user side.
2436 */
2437
2438static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
2439 const unsigned char *buf, size_t nr)
2440{
2441 int space = tty_write_room(tty);
2442 if (space >= nr)
2443 return tty->ops->write(tty, buf, nr);
2444 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2445 return -ENOBUFS;
2446}
2447
2448/**
2449 * gsmld_poll - poll method for N_GSM0710
2450 * @tty: terminal device
2451 * @file: file accessing it
2452 * @wait: poll table
2453 *
2454 * Called when the line discipline is asked to poll() for data or
2455 * for special events. This code is not serialized with respect to
2456 * other events save open/close.
2457 *
2458 * This code must be sure never to sleep through a hangup.
2459 * Called without the kernel lock held - fine
2460 */
2461
2462static unsigned int gsmld_poll(struct tty_struct *tty, struct file *file,
2463 poll_table *wait)
2464{
2465 unsigned int mask = 0;
2466 struct gsm_mux *gsm = tty->disc_data;
2467
2468 poll_wait(file, &tty->read_wait, wait);
2469 poll_wait(file, &tty->write_wait, wait);
2470 if (tty_hung_up_p(file))
2471 mask |= POLLHUP;
2472 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
2473 mask |= POLLOUT | POLLWRNORM;
2474 if (gsm->dead)
2475 mask |= POLLHUP;
2476 return mask;
2477}
2478
2479static int gsmld_config(struct tty_struct *tty, struct gsm_mux *gsm,
2480 struct gsm_config *c)
2481{
2482 int need_close = 0;
2483 int need_restart = 0;
2484
2485 /* Stuff we don't support yet - UI or I frame transport, windowing */
2486 if ((c->adaption != 1 && c->adaption != 2) || c->k)
2487 return -EOPNOTSUPP;
2488 /* Check the MRU/MTU range looks sane */
2489 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8)
2490 return -EINVAL;
2491 if (c->n2 < 3)
2492 return -EINVAL;
2493 if (c->encapsulation > 1) /* Basic, advanced, no I */
2494 return -EINVAL;
2495 if (c->initiator > 1)
2496 return -EINVAL;
2497 if (c->i == 0 || c->i > 2) /* UIH and UI only */
2498 return -EINVAL;
2499 /*
2500 * See what is needed for reconfiguration
2501 */
2502
2503 /* Timing fields */
2504 if (c->t1 != 0 && c->t1 != gsm->t1)
2505 need_restart = 1;
2506 if (c->t2 != 0 && c->t2 != gsm->t2)
2507 need_restart = 1;
2508 if (c->encapsulation != gsm->encoding)
2509 need_restart = 1;
2510 if (c->adaption != gsm->adaption)
2511 need_restart = 1;
2512 /* Requires care */
2513 if (c->initiator != gsm->initiator)
2514 need_close = 1;
2515 if (c->mru != gsm->mru)
2516 need_restart = 1;
2517 if (c->mtu != gsm->mtu)
2518 need_restart = 1;
2519
2520 /*
2521 * Close down what is needed, restart and initiate the new
2522 * configuration
2523 */
2524
2525 if (need_close || need_restart) {
2526 gsm_dlci_begin_close(gsm->dlci[0]);
2527 /* This will timeout if the link is down due to N2 expiring */
2528 wait_event_interruptible(gsm->event,
2529 gsm->dlci[0]->state == DLCI_CLOSED);
2530 if (signal_pending(current))
2531 return -EINTR;
2532 }
2533 if (need_restart)
2534 gsm_cleanup_mux(gsm);
2535
2536 gsm->initiator = c->initiator;
2537 gsm->mru = c->mru;
2538 gsm->mtu = c->mtu;
2539 gsm->encoding = c->encapsulation;
2540 gsm->adaption = c->adaption;
2541 gsm->n2 = c->n2;
2542
2543 if (c->i == 1)
2544 gsm->ftype = UIH;
2545 else if (c->i == 2)
2546 gsm->ftype = UI;
2547
2548 if (c->t1)
2549 gsm->t1 = c->t1;
2550 if (c->t2)
2551 gsm->t2 = c->t2;
2552
2553 /* FIXME: We need to separate activation/deactivation from adding
2554 and removing from the mux array */
2555 if (need_restart)
2556 gsm_activate_mux(gsm);
2557 if (gsm->initiator && need_close)
2558 gsm_dlci_begin_open(gsm->dlci[0]);
2559 return 0;
2560}
2561
2562static int gsmld_ioctl(struct tty_struct *tty, struct file *file,
2563 unsigned int cmd, unsigned long arg)
2564{
2565 struct gsm_config c;
2566 struct gsm_mux *gsm = tty->disc_data;
2567
2568 switch (cmd) {
2569 case GSMIOC_GETCONF:
2570 memset(&c, 0, sizeof(c));
2571 c.adaption = gsm->adaption;
2572 c.encapsulation = gsm->encoding;
2573 c.initiator = gsm->initiator;
2574 c.t1 = gsm->t1;
2575 c.t2 = gsm->t2;
2576 c.t3 = 0; /* Not supported */
2577 c.n2 = gsm->n2;
2578 if (gsm->ftype == UIH)
2579 c.i = 1;
2580 else
2581 c.i = 2;
2582 pr_debug("Ftype %d i %d\n", gsm->ftype, c.i);
2583 c.mru = gsm->mru;
2584 c.mtu = gsm->mtu;
2585 c.k = 0;
2586 if (copy_to_user((void *)arg, &c, sizeof(c)))
2587 return -EFAULT;
2588 return 0;
2589 case GSMIOC_SETCONF:
2590 if (copy_from_user(&c, (void *)arg, sizeof(c)))
2591 return -EFAULT;
2592 return gsmld_config(tty, gsm, &c);
2593 default:
2594 return n_tty_ioctl_helper(tty, file, cmd, arg);
2595 }
2596}
2597
2598/*
2599 * Network interface
2600 *
2601 */
2602
2603static int gsm_mux_net_open(struct net_device *net)
2604{
2605 pr_debug("%s called\n", __func__);
2606 netif_start_queue(net);
2607 return 0;
2608}
2609
2610static int gsm_mux_net_close(struct net_device *net)
2611{
2612 netif_stop_queue(net);
2613 return 0;
2614}
2615
2616static struct net_device_stats *gsm_mux_net_get_stats(struct net_device *net)
2617{
2618 return &((struct gsm_mux_net *)netdev_priv(net))->stats;
2619}
2620static void dlci_net_free(struct gsm_dlci *dlci)
2621{
2622 if (!dlci->net) {
2623 WARN_ON(1);
2624 return;
2625 }
2626 dlci->adaption = dlci->prev_adaption;
2627 dlci->data = dlci->prev_data;
2628 free_netdev(dlci->net);
2629 dlci->net = NULL;
2630}
2631static void net_free(struct kref *ref)
2632{
2633 struct gsm_mux_net *mux_net;
2634 struct gsm_dlci *dlci;
2635
2636 mux_net = container_of(ref, struct gsm_mux_net, ref);
2637 dlci = mux_net->dlci;
2638
2639 if (dlci->net) {
2640 unregister_netdev(dlci->net);
2641 dlci_net_free(dlci);
2642 }
2643}
2644
2645static inline void muxnet_get(struct gsm_mux_net *mux_net)
2646{
2647 kref_get(&mux_net->ref);
2648}
2649
2650static inline void muxnet_put(struct gsm_mux_net *mux_net)
2651{
2652 kref_put(&mux_net->ref, net_free);
2653}
2654
2655static int gsm_mux_net_start_xmit(struct sk_buff *skb,
2656 struct net_device *net)
2657{
2658 struct gsm_mux_net *mux_net = netdev_priv(net);
2659 struct gsm_dlci *dlci = mux_net->dlci;
2660 muxnet_get(mux_net);
2661
2662 skb_queue_head(&dlci->skb_list, skb);
2663 STATS(net).tx_packets++;
2664 STATS(net).tx_bytes += skb->len;
2665 gsm_dlci_data_kick(dlci);
2666 /* And tell the kernel when the last transmit started. */
2667 netif_trans_update(net);
2668 muxnet_put(mux_net);
2669 return NETDEV_TX_OK;
2670}
2671
2672/* called when a packet did not ack after watchdogtimeout */
2673static void gsm_mux_net_tx_timeout(struct net_device *net)
2674{
2675 /* Tell syslog we are hosed. */
2676 dev_dbg(&net->dev, "Tx timed out.\n");
2677
2678 /* Update statistics */
2679 STATS(net).tx_errors++;
2680}
2681
2682static void gsm_mux_rx_netchar(struct gsm_dlci *dlci,
2683 unsigned char *in_buf, int size)
2684{
2685 struct net_device *net = dlci->net;
2686 struct sk_buff *skb;
2687 struct gsm_mux_net *mux_net = netdev_priv(net);
2688 muxnet_get(mux_net);
2689
2690 /* Allocate an sk_buff */
2691 skb = dev_alloc_skb(size + NET_IP_ALIGN);
2692 if (!skb) {
2693 /* We got no receive buffer. */
2694 STATS(net).rx_dropped++;
2695 muxnet_put(mux_net);
2696 return;
2697 }
2698 skb_reserve(skb, NET_IP_ALIGN);
2699 memcpy(skb_put(skb, size), in_buf, size);
2700
2701 skb->dev = net;
2702 skb->protocol = htons(ETH_P_IP);
2703
2704 /* Ship it off to the kernel */
2705 netif_rx(skb);
2706
2707 /* update out statistics */
2708 STATS(net).rx_packets++;
2709 STATS(net).rx_bytes += size;
2710 muxnet_put(mux_net);
2711 return;
2712}
2713
2714static void gsm_mux_net_init(struct net_device *net)
2715{
2716 static const struct net_device_ops gsm_netdev_ops = {
2717 .ndo_open = gsm_mux_net_open,
2718 .ndo_stop = gsm_mux_net_close,
2719 .ndo_start_xmit = gsm_mux_net_start_xmit,
2720 .ndo_tx_timeout = gsm_mux_net_tx_timeout,
2721 .ndo_get_stats = gsm_mux_net_get_stats,
2722 };
2723
2724 net->netdev_ops = &gsm_netdev_ops;
2725
2726 /* fill in the other fields */
2727 net->watchdog_timeo = GSM_NET_TX_TIMEOUT;
2728 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
2729 net->type = ARPHRD_NONE;
2730 net->tx_queue_len = 10;
2731}
2732
2733
2734/* caller holds the dlci mutex */
2735static void gsm_destroy_network(struct gsm_dlci *dlci)
2736{
2737 struct gsm_mux_net *mux_net;
2738
2739 pr_debug("destroy network interface");
2740 if (!dlci->net)
2741 return;
2742 mux_net = netdev_priv(dlci->net);
2743 muxnet_put(mux_net);
2744}
2745
2746
2747/* caller holds the dlci mutex */
2748static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
2749{
2750 char *netname;
2751 int retval = 0;
2752 struct net_device *net;
2753 struct gsm_mux_net *mux_net;
2754
2755 if (!capable(CAP_NET_ADMIN))
2756 return -EPERM;
2757
2758 /* Already in a non tty mode */
2759 if (dlci->adaption > 2)
2760 return -EBUSY;
2761
2762 if (nc->protocol != htons(ETH_P_IP))
2763 return -EPROTONOSUPPORT;
2764
2765 if (nc->adaption != 3 && nc->adaption != 4)
2766 return -EPROTONOSUPPORT;
2767
2768 pr_debug("create network interface");
2769
2770 netname = "gsm%d";
2771 if (nc->if_name[0] != '\0')
2772 netname = nc->if_name;
2773 net = alloc_netdev(sizeof(struct gsm_mux_net), netname,
2774 NET_NAME_UNKNOWN, gsm_mux_net_init);
2775 if (!net) {
2776 pr_err("alloc_netdev failed");
2777 return -ENOMEM;
2778 }
2779 net->mtu = dlci->gsm->mtu;
2780 net->min_mtu = 8;
2781 net->max_mtu = dlci->gsm->mtu;
2782 mux_net = netdev_priv(net);
2783 mux_net->dlci = dlci;
2784 kref_init(&mux_net->ref);
2785 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */
2786
2787 /* reconfigure dlci for network */
2788 dlci->prev_adaption = dlci->adaption;
2789 dlci->prev_data = dlci->data;
2790 dlci->adaption = nc->adaption;
2791 dlci->data = gsm_mux_rx_netchar;
2792 dlci->net = net;
2793
2794 pr_debug("register netdev");
2795 retval = register_netdev(net);
2796 if (retval) {
2797 pr_err("network register fail %d\n", retval);
2798 dlci_net_free(dlci);
2799 return retval;
2800 }
2801 return net->ifindex; /* return network index */
2802}
2803
2804/* Line discipline for real tty */
2805static struct tty_ldisc_ops tty_ldisc_packet = {
2806 .owner = THIS_MODULE,
2807 .magic = TTY_LDISC_MAGIC,
2808 .name = "n_gsm",
2809 .open = gsmld_open,
2810 .close = gsmld_close,
2811 .flush_buffer = gsmld_flush_buffer,
2812 .read = gsmld_read,
2813 .write = gsmld_write,
2814 .ioctl = gsmld_ioctl,
2815 .poll = gsmld_poll,
2816 .receive_buf = gsmld_receive_buf,
2817 .write_wakeup = gsmld_write_wakeup
2818};
2819
2820/*
2821 * Virtual tty side
2822 */
2823
2824#define TX_SIZE 512
2825
2826static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk)
2827{
2828 u8 modembits[5];
2829 struct gsm_control *ctrl;
2830 int len = 2;
2831
2832 if (brk)
2833 len++;
2834
2835 modembits[0] = len << 1 | EA; /* Data bytes */
2836 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */
2837 modembits[2] = gsm_encode_modem(dlci) << 1 | EA;
2838 if (brk)
2839 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */
2840 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1);
2841 if (ctrl == NULL)
2842 return -ENOMEM;
2843 return gsm_control_wait(dlci->gsm, ctrl);
2844}
2845
2846static int gsm_carrier_raised(struct tty_port *port)
2847{
2848 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2849 /* Not yet open so no carrier info */
2850 if (dlci->state != DLCI_OPEN)
2851 return 0;
2852 if (debug & 2)
2853 return 1;
2854 return dlci->modem_rx & TIOCM_CD;
2855}
2856
2857static void gsm_dtr_rts(struct tty_port *port, int onoff)
2858{
2859 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2860 unsigned int modem_tx = dlci->modem_tx;
2861 if (onoff)
2862 modem_tx |= TIOCM_DTR | TIOCM_RTS;
2863 else
2864 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
2865 if (modem_tx != dlci->modem_tx) {
2866 dlci->modem_tx = modem_tx;
2867 gsmtty_modem_update(dlci, 0);
2868 }
2869}
2870
2871static const struct tty_port_operations gsm_port_ops = {
2872 .carrier_raised = gsm_carrier_raised,
2873 .dtr_rts = gsm_dtr_rts,
2874 .destruct = gsm_dlci_free,
2875};
2876
2877static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty)
2878{
2879 struct gsm_mux *gsm;
2880 struct gsm_dlci *dlci;
2881 unsigned int line = tty->index;
2882 unsigned int mux = line >> 6;
2883 bool alloc = false;
2884 int ret;
2885
2886 line = line & 0x3F;
2887
2888 if (mux >= MAX_MUX)
2889 return -ENXIO;
2890 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
2891 if (gsm_mux[mux] == NULL)
2892 return -EUNATCH;
2893 if (line == 0 || line > 61) /* 62/63 reserved */
2894 return -ECHRNG;
2895 gsm = gsm_mux[mux];
2896 if (gsm->dead)
2897 return -EL2HLT;
2898 /* If DLCI 0 is not yet fully open return an error.
2899 This is ok from a locking
2900 perspective as we don't have to worry about this
2901 if DLCI0 is lost */
2902 mutex_lock(&gsm->mutex);
2903 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN) {
2904 mutex_unlock(&gsm->mutex);
2905 return -EL2NSYNC;
2906 }
2907 dlci = gsm->dlci[line];
2908 if (dlci == NULL) {
2909 alloc = true;
2910 dlci = gsm_dlci_alloc(gsm, line);
2911 }
2912 if (dlci == NULL) {
2913 mutex_unlock(&gsm->mutex);
2914 return -ENOMEM;
2915 }
2916 ret = tty_port_install(&dlci->port, driver, tty);
2917 if (ret) {
2918 if (alloc)
2919 dlci_put(dlci);
2920 mutex_unlock(&gsm->mutex);
2921 return ret;
2922 }
2923
2924 dlci_get(dlci);
2925 dlci_get(gsm->dlci[0]);
2926 mux_get(gsm);
2927 tty->driver_data = dlci;
2928 mutex_unlock(&gsm->mutex);
2929
2930 return 0;
2931}
2932
2933static int gsmtty_open(struct tty_struct *tty, struct file *filp)
2934{
2935 struct gsm_dlci *dlci = tty->driver_data;
2936 struct tty_port *port = &dlci->port;
2937
2938 port->count++;
2939 tty_port_tty_set(port, tty);
2940
2941 dlci->modem_rx = 0;
2942 /* We could in theory open and close before we wait - eg if we get
2943 a DM straight back. This is ok as that will have caused a hangup */
2944 tty_port_set_initialized(port, 1);
2945 /* Start sending off SABM messages */
2946 gsm_dlci_begin_open(dlci);
2947 /* And wait for virtual carrier */
2948 return tty_port_block_til_ready(port, tty, filp);
2949}
2950
2951static void gsmtty_close(struct tty_struct *tty, struct file *filp)
2952{
2953 struct gsm_dlci *dlci = tty->driver_data;
2954 struct gsm_mux *gsm;
2955
2956 if (dlci == NULL)
2957 return;
2958 if (dlci->state == DLCI_CLOSED)
2959 return;
2960 mutex_lock(&dlci->mutex);
2961 gsm_destroy_network(dlci);
2962 mutex_unlock(&dlci->mutex);
2963 gsm = dlci->gsm;
2964 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
2965 return;
2966 gsm_dlci_begin_close(dlci);
2967 if (tty_port_initialized(&dlci->port) && C_HUPCL(tty))
2968 tty_port_lower_dtr_rts(&dlci->port);
2969 tty_port_close_end(&dlci->port, tty);
2970 tty_port_tty_set(&dlci->port, NULL);
2971 return;
2972}
2973
2974static void gsmtty_hangup(struct tty_struct *tty)
2975{
2976 struct gsm_dlci *dlci = tty->driver_data;
2977 if (dlci->state == DLCI_CLOSED)
2978 return;
2979 tty_port_hangup(&dlci->port);
2980 gsm_dlci_begin_close(dlci);
2981}
2982
2983static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf,
2984 int len)
2985{
2986 int sent;
2987 struct gsm_dlci *dlci = tty->driver_data;
2988 if (dlci->state == DLCI_CLOSED)
2989 return -EINVAL;
2990 /* Stuff the bytes into the fifo queue */
2991 sent = kfifo_in_locked(dlci->fifo, buf, len, &dlci->lock);
2992 /* Need to kick the channel */
2993 gsm_dlci_data_kick(dlci);
2994 return sent;
2995}
2996
2997static int gsmtty_write_room(struct tty_struct *tty)
2998{
2999 struct gsm_dlci *dlci = tty->driver_data;
3000 if (dlci->state == DLCI_CLOSED)
3001 return -EINVAL;
3002 return TX_SIZE - kfifo_len(dlci->fifo);
3003}
3004
3005static int gsmtty_chars_in_buffer(struct tty_struct *tty)
3006{
3007 struct gsm_dlci *dlci = tty->driver_data;
3008 if (dlci->state == DLCI_CLOSED)
3009 return -EINVAL;
3010 return kfifo_len(dlci->fifo);
3011}
3012
3013static void gsmtty_flush_buffer(struct tty_struct *tty)
3014{
3015 struct gsm_dlci *dlci = tty->driver_data;
3016 if (dlci->state == DLCI_CLOSED)
3017 return;
3018 /* Caution needed: If we implement reliable transport classes
3019 then the data being transmitted can't simply be junked once
3020 it has first hit the stack. Until then we can just blow it
3021 away */
3022 kfifo_reset(dlci->fifo);
3023 /* Need to unhook this DLCI from the transmit queue logic */
3024}
3025
3026static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
3027{
3028 /* The FIFO handles the queue so the kernel will do the right
3029 thing waiting on chars_in_buffer before calling us. No work
3030 to do here */
3031}
3032
3033static int gsmtty_tiocmget(struct tty_struct *tty)
3034{
3035 struct gsm_dlci *dlci = tty->driver_data;
3036 if (dlci->state == DLCI_CLOSED)
3037 return -EINVAL;
3038 return dlci->modem_rx;
3039}
3040
3041static int gsmtty_tiocmset(struct tty_struct *tty,
3042 unsigned int set, unsigned int clear)
3043{
3044 struct gsm_dlci *dlci = tty->driver_data;
3045 unsigned int modem_tx = dlci->modem_tx;
3046
3047 if (dlci->state == DLCI_CLOSED)
3048 return -EINVAL;
3049 modem_tx &= ~clear;
3050 modem_tx |= set;
3051
3052 if (modem_tx != dlci->modem_tx) {
3053 dlci->modem_tx = modem_tx;
3054 return gsmtty_modem_update(dlci, 0);
3055 }
3056 return 0;
3057}
3058
3059
3060static int gsmtty_ioctl(struct tty_struct *tty,
3061 unsigned int cmd, unsigned long arg)
3062{
3063 struct gsm_dlci *dlci = tty->driver_data;
3064 struct gsm_netconfig nc;
3065 int index;
3066
3067 if (dlci->state == DLCI_CLOSED)
3068 return -EINVAL;
3069 switch (cmd) {
3070 case GSMIOC_ENABLE_NET:
3071 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc)))
3072 return -EFAULT;
3073 nc.if_name[IFNAMSIZ-1] = '\0';
3074 /* return net interface index or error code */
3075 mutex_lock(&dlci->mutex);
3076 index = gsm_create_network(dlci, &nc);
3077 mutex_unlock(&dlci->mutex);
3078 if (copy_to_user((void __user *)arg, &nc, sizeof(nc)))
3079 return -EFAULT;
3080 return index;
3081 case GSMIOC_DISABLE_NET:
3082 if (!capable(CAP_NET_ADMIN))
3083 return -EPERM;
3084 mutex_lock(&dlci->mutex);
3085 gsm_destroy_network(dlci);
3086 mutex_unlock(&dlci->mutex);
3087 return 0;
3088 default:
3089 return -ENOIOCTLCMD;
3090 }
3091}
3092
3093static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old)
3094{
3095 struct gsm_dlci *dlci = tty->driver_data;
3096 if (dlci->state == DLCI_CLOSED)
3097 return;
3098 /* For the moment its fixed. In actual fact the speed information
3099 for the virtual channel can be propogated in both directions by
3100 the RPN control message. This however rapidly gets nasty as we
3101 then have to remap modem signals each way according to whether
3102 our virtual cable is null modem etc .. */
3103 tty_termios_copy_hw(&tty->termios, old);
3104}
3105
3106static void gsmtty_throttle(struct tty_struct *tty)
3107{
3108 struct gsm_dlci *dlci = tty->driver_data;
3109 if (dlci->state == DLCI_CLOSED)
3110 return;
3111 if (C_CRTSCTS(tty))
3112 dlci->modem_tx &= ~TIOCM_DTR;
3113 dlci->throttled = 1;
3114 /* Send an MSC with DTR cleared */
3115 gsmtty_modem_update(dlci, 0);
3116}
3117
3118static void gsmtty_unthrottle(struct tty_struct *tty)
3119{
3120 struct gsm_dlci *dlci = tty->driver_data;
3121 if (dlci->state == DLCI_CLOSED)
3122 return;
3123 if (C_CRTSCTS(tty))
3124 dlci->modem_tx |= TIOCM_DTR;
3125 dlci->throttled = 0;
3126 /* Send an MSC with DTR set */
3127 gsmtty_modem_update(dlci, 0);
3128}
3129
3130static int gsmtty_break_ctl(struct tty_struct *tty, int state)
3131{
3132 struct gsm_dlci *dlci = tty->driver_data;
3133 int encode = 0; /* Off */
3134 if (dlci->state == DLCI_CLOSED)
3135 return -EINVAL;
3136
3137 if (state == -1) /* "On indefinitely" - we can't encode this
3138 properly */
3139 encode = 0x0F;
3140 else if (state > 0) {
3141 encode = state / 200; /* mS to encoding */
3142 if (encode > 0x0F)
3143 encode = 0x0F; /* Best effort */
3144 }
3145 return gsmtty_modem_update(dlci, encode);
3146}
3147
3148static void gsmtty_cleanup(struct tty_struct *tty)
3149{
3150 struct gsm_dlci *dlci = tty->driver_data;
3151 struct gsm_mux *gsm = dlci->gsm;
3152
3153 dlci_put(dlci);
3154 dlci_put(gsm->dlci[0]);
3155 mux_put(gsm);
3156}
3157
3158/* Virtual ttys for the demux */
3159static const struct tty_operations gsmtty_ops = {
3160 .install = gsmtty_install,
3161 .open = gsmtty_open,
3162 .close = gsmtty_close,
3163 .write = gsmtty_write,
3164 .write_room = gsmtty_write_room,
3165 .chars_in_buffer = gsmtty_chars_in_buffer,
3166 .flush_buffer = gsmtty_flush_buffer,
3167 .ioctl = gsmtty_ioctl,
3168 .throttle = gsmtty_throttle,
3169 .unthrottle = gsmtty_unthrottle,
3170 .set_termios = gsmtty_set_termios,
3171 .hangup = gsmtty_hangup,
3172 .wait_until_sent = gsmtty_wait_until_sent,
3173 .tiocmget = gsmtty_tiocmget,
3174 .tiocmset = gsmtty_tiocmset,
3175 .break_ctl = gsmtty_break_ctl,
3176 .cleanup = gsmtty_cleanup,
3177};
3178
3179
3180
3181static int __init gsm_init(void)
3182{
3183 /* Fill in our line protocol discipline, and register it */
3184 int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet);
3185 if (status != 0) {
3186 pr_err("n_gsm: can't register line discipline (err = %d)\n",
3187 status);
3188 return status;
3189 }
3190
3191 gsm_tty_driver = alloc_tty_driver(256);
3192 if (!gsm_tty_driver) {
3193 tty_unregister_ldisc(N_GSM0710);
3194 pr_err("gsm_init: tty allocation failed.\n");
3195 return -EINVAL;
3196 }
3197 gsm_tty_driver->driver_name = "gsmtty";
3198 gsm_tty_driver->name = "gsmtty";
3199 gsm_tty_driver->major = 0; /* Dynamic */
3200 gsm_tty_driver->minor_start = 0;
3201 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
3202 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
3203 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV
3204 | TTY_DRIVER_HARDWARE_BREAK;
3205 gsm_tty_driver->init_termios = tty_std_termios;
3206 /* Fixme */
3207 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
3208 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
3209
3210 spin_lock_init(&gsm_mux_lock);
3211
3212 if (tty_register_driver(gsm_tty_driver)) {
3213 put_tty_driver(gsm_tty_driver);
3214 tty_unregister_ldisc(N_GSM0710);
3215 pr_err("gsm_init: tty registration failed.\n");
3216 return -EBUSY;
3217 }
3218 pr_debug("gsm_init: loaded as %d,%d.\n",
3219 gsm_tty_driver->major, gsm_tty_driver->minor_start);
3220 return 0;
3221}
3222
3223static void __exit gsm_exit(void)
3224{
3225 int status = tty_unregister_ldisc(N_GSM0710);
3226 if (status != 0)
3227 pr_err("n_gsm: can't unregister line discipline (err = %d)\n",
3228 status);
3229 tty_unregister_driver(gsm_tty_driver);
3230 put_tty_driver(gsm_tty_driver);
3231}
3232
3233module_init(gsm_init);
3234module_exit(gsm_exit);
3235
3236
3237MODULE_LICENSE("GPL");
3238MODULE_ALIAS_LDISC(N_GSM0710);