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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// SPDX-License-Identifier: GPL-2.0
2/*
3 * n_gsm.c GSM 0710 tty multiplexor
4 * Copyright (c) 2009/10 Intel Corporation
5 *
6 * * THIS IS A DEVELOPMENT SNAPSHOT IT IS NOT A FINAL RELEASE *
7 *
8 * TO DO:
9 * Mostly done: ioctls for setting modes/timing
10 * Partly done: hooks so you can pull off frames to non tty devs
11 * Restart DLCI 0 when it closes ?
12 * Improve the tx engine
13 * Resolve tx side locking by adding a queue_head and routing
14 * all control traffic via it
15 * General tidy/document
16 * Review the locking/move to refcounts more (mux now moved to an
17 * alloc/free model ready)
18 * Use newest tty open/close port helpers and install hooks
19 * What to do about power functions ?
20 * Termios setting and negotiation
21 * Do we need a 'which mux are you' ioctl to correlate mux and tty sets
22 *
23 */
24
25#include <linux/types.h>
26#include <linux/major.h>
27#include <linux/errno.h>
28#include <linux/signal.h>
29#include <linux/fcntl.h>
30#include <linux/sched/signal.h>
31#include <linux/interrupt.h>
32#include <linux/tty.h>
33#include <linux/ctype.h>
34#include <linux/mm.h>
35#include <linux/string.h>
36#include <linux/slab.h>
37#include <linux/poll.h>
38#include <linux/bitops.h>
39#include <linux/file.h>
40#include <linux/uaccess.h>
41#include <linux/module.h>
42#include <linux/timer.h>
43#include <linux/tty_flip.h>
44#include <linux/tty_driver.h>
45#include <linux/serial.h>
46#include <linux/kfifo.h>
47#include <linux/skbuff.h>
48#include <net/arp.h>
49#include <linux/ip.h>
50#include <linux/netdevice.h>
51#include <linux/etherdevice.h>
52#include <linux/gsmmux.h>
53
54static int debug;
55module_param(debug, int, 0600);
56
57/* Defaults: these are from the specification */
58
59#define T1 10 /* 100mS */
60#define T2 34 /* 333mS */
61#define N2 3 /* Retry 3 times */
62
63/* Use long timers for testing at low speed with debug on */
64#ifdef DEBUG_TIMING
65#define T1 100
66#define T2 200
67#endif
68
69/*
70 * Semi-arbitrary buffer size limits. 0710 is normally run with 32-64 byte
71 * limits so this is plenty
72 */
73#define MAX_MRU 1500
74#define MAX_MTU 1500
75#define GSM_NET_TX_TIMEOUT (HZ*10)
76
77/**
78 * struct gsm_mux_net - network interface
79 * @struct gsm_dlci* dlci
80 *
81 * Created when net interface is initialized.
82 **/
83struct gsm_mux_net {
84 struct kref ref;
85 struct gsm_dlci *dlci;
86};
87
88/*
89 * Each block of data we have queued to go out is in the form of
90 * a gsm_msg which holds everything we need in a link layer independent
91 * format
92 */
93
94struct gsm_msg {
95 struct list_head list;
96 u8 addr; /* DLCI address + flags */
97 u8 ctrl; /* Control byte + flags */
98 unsigned int len; /* Length of data block (can be zero) */
99 unsigned char *data; /* Points into buffer but not at the start */
100 unsigned char buffer[0];
101};
102
103/*
104 * Each active data link has a gsm_dlci structure associated which ties
105 * the link layer to an optional tty (if the tty side is open). To avoid
106 * complexity right now these are only ever freed up when the mux is
107 * shut down.
108 *
109 * At the moment we don't free DLCI objects until the mux is torn down
110 * this avoid object life time issues but might be worth review later.
111 */
112
113struct gsm_dlci {
114 struct gsm_mux *gsm;
115 int addr;
116 int state;
117#define DLCI_CLOSED 0
118#define DLCI_OPENING 1 /* Sending SABM not seen UA */
119#define DLCI_OPEN 2 /* SABM/UA complete */
120#define DLCI_CLOSING 3 /* Sending DISC not seen UA/DM */
121 struct mutex mutex;
122
123 /* Link layer */
124 int mode;
125#define DLCI_MODE_ABM 0 /* Normal Asynchronous Balanced Mode */
126#define DLCI_MODE_ADM 1 /* Asynchronous Disconnected Mode */
127 spinlock_t lock; /* Protects the internal state */
128 struct timer_list t1; /* Retransmit timer for SABM and UA */
129 int retries;
130 /* Uplink tty if active */
131 struct tty_port port; /* The tty bound to this DLCI if there is one */
132 struct kfifo *fifo; /* Queue fifo for the DLCI */
133 struct kfifo _fifo; /* For new fifo API porting only */
134 int adaption; /* Adaption layer in use */
135 int prev_adaption;
136 u32 modem_rx; /* Our incoming virtual modem lines */
137 u32 modem_tx; /* Our outgoing modem lines */
138 int dead; /* Refuse re-open */
139 /* Flow control */
140 int throttled; /* Private copy of throttle state */
141 int constipated; /* Throttle status for outgoing */
142 /* Packetised I/O */
143 struct sk_buff *skb; /* Frame being sent */
144 struct sk_buff_head skb_list; /* Queued frames */
145 /* Data handling callback */
146 void (*data)(struct gsm_dlci *dlci, const u8 *data, int len);
147 void (*prev_data)(struct gsm_dlci *dlci, const u8 *data, int len);
148 struct net_device *net; /* network interface, if created */
149};
150
151/* DLCI 0, 62/63 are special or reserved see gsmtty_open */
152
153#define NUM_DLCI 64
154
155/*
156 * DLCI 0 is used to pass control blocks out of band of the data
157 * flow (and with a higher link priority). One command can be outstanding
158 * at a time and we use this structure to manage them. They are created
159 * and destroyed by the user context, and updated by the receive paths
160 * and timers
161 */
162
163struct gsm_control {
164 u8 cmd; /* Command we are issuing */
165 u8 *data; /* Data for the command in case we retransmit */
166 int len; /* Length of block for retransmission */
167 int done; /* Done flag */
168 int error; /* Error if any */
169};
170
171/*
172 * Each GSM mux we have is represented by this structure. If we are
173 * operating as an ldisc then we use this structure as our ldisc
174 * state. We need to sort out lifetimes and locking with respect
175 * to the gsm mux array. For now we don't free DLCI objects that
176 * have been instantiated until the mux itself is terminated.
177 *
178 * To consider further: tty open versus mux shutdown.
179 */
180
181struct gsm_mux {
182 struct tty_struct *tty; /* The tty our ldisc is bound to */
183 spinlock_t lock;
184 struct mutex mutex;
185 unsigned int num;
186 struct kref ref;
187
188 /* Events on the GSM channel */
189 wait_queue_head_t event;
190
191 /* Bits for GSM mode decoding */
192
193 /* Framing Layer */
194 unsigned char *buf;
195 int state;
196#define GSM_SEARCH 0
197#define GSM_START 1
198#define GSM_ADDRESS 2
199#define GSM_CONTROL 3
200#define GSM_LEN 4
201#define GSM_DATA 5
202#define GSM_FCS 6
203#define GSM_OVERRUN 7
204#define GSM_LEN0 8
205#define GSM_LEN1 9
206#define GSM_SSOF 10
207 unsigned int len;
208 unsigned int address;
209 unsigned int count;
210 int escape;
211 int encoding;
212 u8 control;
213 u8 fcs;
214 u8 received_fcs;
215 u8 *txframe; /* TX framing buffer */
216
217 /* Methods for the receiver side */
218 void (*receive)(struct gsm_mux *gsm, u8 ch);
219 void (*error)(struct gsm_mux *gsm, u8 ch, u8 flag);
220 /* And transmit side */
221 int (*output)(struct gsm_mux *mux, u8 *data, int len);
222
223 /* Link Layer */
224 unsigned int mru;
225 unsigned int mtu;
226 int initiator; /* Did we initiate connection */
227 int dead; /* Has the mux been shut down */
228 struct gsm_dlci *dlci[NUM_DLCI];
229 int constipated; /* Asked by remote to shut up */
230
231 spinlock_t tx_lock;
232 unsigned int tx_bytes; /* TX data outstanding */
233#define TX_THRESH_HI 8192
234#define TX_THRESH_LO 2048
235 struct list_head tx_list; /* Pending data packets */
236
237 /* Control messages */
238 struct timer_list t2_timer; /* Retransmit timer for commands */
239 int cretries; /* Command retry counter */
240 struct gsm_control *pending_cmd;/* Our current pending command */
241 spinlock_t control_lock; /* Protects the pending command */
242
243 /* Configuration */
244 int adaption; /* 1 or 2 supported */
245 u8 ftype; /* UI or UIH */
246 int t1, t2; /* Timers in 1/100th of a sec */
247 int n2; /* Retry count */
248
249 /* Statistics (not currently exposed) */
250 unsigned long bad_fcs;
251 unsigned long malformed;
252 unsigned long io_error;
253 unsigned long bad_size;
254 unsigned long unsupported;
255};
256
257
258/*
259 * Mux objects - needed so that we can translate a tty index into the
260 * relevant mux and DLCI.
261 */
262
263#define MAX_MUX 4 /* 256 minors */
264static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */
265static spinlock_t gsm_mux_lock;
266
267static struct tty_driver *gsm_tty_driver;
268
269/*
270 * This section of the driver logic implements the GSM encodings
271 * both the basic and the 'advanced'. Reliable transport is not
272 * supported.
273 */
274
275#define CR 0x02
276#define EA 0x01
277#define PF 0x10
278
279/* I is special: the rest are ..*/
280#define RR 0x01
281#define UI 0x03
282#define RNR 0x05
283#define REJ 0x09
284#define DM 0x0F
285#define SABM 0x2F
286#define DISC 0x43
287#define UA 0x63
288#define UIH 0xEF
289
290/* Channel commands */
291#define CMD_NSC 0x09
292#define CMD_TEST 0x11
293#define CMD_PSC 0x21
294#define CMD_RLS 0x29
295#define CMD_FCOFF 0x31
296#define CMD_PN 0x41
297#define CMD_RPN 0x49
298#define CMD_FCON 0x51
299#define CMD_CLD 0x61
300#define CMD_SNC 0x69
301#define CMD_MSC 0x71
302
303/* Virtual modem bits */
304#define MDM_FC 0x01
305#define MDM_RTC 0x02
306#define MDM_RTR 0x04
307#define MDM_IC 0x20
308#define MDM_DV 0x40
309
310#define GSM0_SOF 0xF9
311#define GSM1_SOF 0x7E
312#define GSM1_ESCAPE 0x7D
313#define GSM1_ESCAPE_BITS 0x20
314#define XON 0x11
315#define XOFF 0x13
316
317static const struct tty_port_operations gsm_port_ops;
318
319/*
320 * CRC table for GSM 0710
321 */
322
323static const u8 gsm_fcs8[256] = {
324 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75,
325 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B,
326 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69,
327 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67,
328 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D,
329 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43,
330 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51,
331 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F,
332 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05,
333 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B,
334 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19,
335 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17,
336 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D,
337 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33,
338 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21,
339 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F,
340 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95,
341 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B,
342 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89,
343 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87,
344 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD,
345 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3,
346 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1,
347 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF,
348 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5,
349 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB,
350 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9,
351 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7,
352 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD,
353 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3,
354 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1,
355 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF
356};
357
358#define INIT_FCS 0xFF
359#define GOOD_FCS 0xCF
360
361/**
362 * gsm_fcs_add - update FCS
363 * @fcs: Current FCS
364 * @c: Next data
365 *
366 * Update the FCS to include c. Uses the algorithm in the specification
367 * notes.
368 */
369
370static inline u8 gsm_fcs_add(u8 fcs, u8 c)
371{
372 return gsm_fcs8[fcs ^ c];
373}
374
375/**
376 * gsm_fcs_add_block - update FCS for a block
377 * @fcs: Current FCS
378 * @c: buffer of data
379 * @len: length of buffer
380 *
381 * Update the FCS to include c. Uses the algorithm in the specification
382 * notes.
383 */
384
385static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len)
386{
387 while (len--)
388 fcs = gsm_fcs8[fcs ^ *c++];
389 return fcs;
390}
391
392/**
393 * gsm_read_ea - read a byte into an EA
394 * @val: variable holding value
395 * c: byte going into the EA
396 *
397 * Processes one byte of an EA. Updates the passed variable
398 * and returns 1 if the EA is now completely read
399 */
400
401static int gsm_read_ea(unsigned int *val, u8 c)
402{
403 /* Add the next 7 bits into the value */
404 *val <<= 7;
405 *val |= c >> 1;
406 /* Was this the last byte of the EA 1 = yes*/
407 return c & EA;
408}
409
410/**
411 * gsm_encode_modem - encode modem data bits
412 * @dlci: DLCI to encode from
413 *
414 * Returns the correct GSM encoded modem status bits (6 bit field) for
415 * the current status of the DLCI and attached tty object
416 */
417
418static u8 gsm_encode_modem(const struct gsm_dlci *dlci)
419{
420 u8 modembits = 0;
421 /* FC is true flow control not modem bits */
422 if (dlci->throttled)
423 modembits |= MDM_FC;
424 if (dlci->modem_tx & TIOCM_DTR)
425 modembits |= MDM_RTC;
426 if (dlci->modem_tx & TIOCM_RTS)
427 modembits |= MDM_RTR;
428 if (dlci->modem_tx & TIOCM_RI)
429 modembits |= MDM_IC;
430 if (dlci->modem_tx & TIOCM_CD)
431 modembits |= MDM_DV;
432 return modembits;
433}
434
435/**
436 * gsm_print_packet - display a frame for debug
437 * @hdr: header to print before decode
438 * @addr: address EA from the frame
439 * @cr: C/R bit from the frame
440 * @control: control including PF bit
441 * @data: following data bytes
442 * @dlen: length of data
443 *
444 * Displays a packet in human readable format for debugging purposes. The
445 * style is based on amateur radio LAP-B dump display.
446 */
447
448static void gsm_print_packet(const char *hdr, int addr, int cr,
449 u8 control, const u8 *data, int dlen)
450{
451 if (!(debug & 1))
452 return;
453
454 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]);
455
456 switch (control & ~PF) {
457 case SABM:
458 pr_cont("SABM");
459 break;
460 case UA:
461 pr_cont("UA");
462 break;
463 case DISC:
464 pr_cont("DISC");
465 break;
466 case DM:
467 pr_cont("DM");
468 break;
469 case UI:
470 pr_cont("UI");
471 break;
472 case UIH:
473 pr_cont("UIH");
474 break;
475 default:
476 if (!(control & 0x01)) {
477 pr_cont("I N(S)%d N(R)%d",
478 (control & 0x0E) >> 1, (control & 0xE0) >> 5);
479 } else switch (control & 0x0F) {
480 case RR:
481 pr_cont("RR(%d)", (control & 0xE0) >> 5);
482 break;
483 case RNR:
484 pr_cont("RNR(%d)", (control & 0xE0) >> 5);
485 break;
486 case REJ:
487 pr_cont("REJ(%d)", (control & 0xE0) >> 5);
488 break;
489 default:
490 pr_cont("[%02X]", control);
491 }
492 }
493
494 if (control & PF)
495 pr_cont("(P)");
496 else
497 pr_cont("(F)");
498
499 if (dlen) {
500 int ct = 0;
501 while (dlen--) {
502 if (ct % 8 == 0) {
503 pr_cont("\n");
504 pr_debug(" ");
505 }
506 pr_cont("%02X ", *data++);
507 ct++;
508 }
509 }
510 pr_cont("\n");
511}
512
513
514/*
515 * Link level transmission side
516 */
517
518/**
519 * gsm_stuff_packet - bytestuff a packet
520 * @ibuf: input
521 * @obuf: output
522 * @len: length of input
523 *
524 * Expand a buffer by bytestuffing it. The worst case size change
525 * is doubling and the caller is responsible for handing out
526 * suitable sized buffers.
527 */
528
529static int gsm_stuff_frame(const u8 *input, u8 *output, int len)
530{
531 int olen = 0;
532 while (len--) {
533 if (*input == GSM1_SOF || *input == GSM1_ESCAPE
534 || *input == XON || *input == XOFF) {
535 *output++ = GSM1_ESCAPE;
536 *output++ = *input++ ^ GSM1_ESCAPE_BITS;
537 olen++;
538 } else
539 *output++ = *input++;
540 olen++;
541 }
542 return olen;
543}
544
545/**
546 * gsm_send - send a control frame
547 * @gsm: our GSM mux
548 * @addr: address for control frame
549 * @cr: command/response bit
550 * @control: control byte including PF bit
551 *
552 * Format up and transmit a control frame. These do not go via the
553 * queueing logic as they should be transmitted ahead of data when
554 * they are needed.
555 *
556 * FIXME: Lock versus data TX path
557 */
558
559static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control)
560{
561 int len;
562 u8 cbuf[10];
563 u8 ibuf[3];
564
565 switch (gsm->encoding) {
566 case 0:
567 cbuf[0] = GSM0_SOF;
568 cbuf[1] = (addr << 2) | (cr << 1) | EA;
569 cbuf[2] = control;
570 cbuf[3] = EA; /* Length of data = 0 */
571 cbuf[4] = 0xFF - gsm_fcs_add_block(INIT_FCS, cbuf + 1, 3);
572 cbuf[5] = GSM0_SOF;
573 len = 6;
574 break;
575 case 1:
576 case 2:
577 /* Control frame + packing (but not frame stuffing) in mode 1 */
578 ibuf[0] = (addr << 2) | (cr << 1) | EA;
579 ibuf[1] = control;
580 ibuf[2] = 0xFF - gsm_fcs_add_block(INIT_FCS, ibuf, 2);
581 /* Stuffing may double the size worst case */
582 len = gsm_stuff_frame(ibuf, cbuf + 1, 3);
583 /* Now add the SOF markers */
584 cbuf[0] = GSM1_SOF;
585 cbuf[len + 1] = GSM1_SOF;
586 /* FIXME: we can omit the lead one in many cases */
587 len += 2;
588 break;
589 default:
590 WARN_ON(1);
591 return;
592 }
593 gsm->output(gsm, cbuf, len);
594 gsm_print_packet("-->", addr, cr, control, NULL, 0);
595}
596
597/**
598 * gsm_response - send a control response
599 * @gsm: our GSM mux
600 * @addr: address for control frame
601 * @control: control byte including PF bit
602 *
603 * Format up and transmit a link level response frame.
604 */
605
606static inline void gsm_response(struct gsm_mux *gsm, int addr, int control)
607{
608 gsm_send(gsm, addr, 0, control);
609}
610
611/**
612 * gsm_command - send a control command
613 * @gsm: our GSM mux
614 * @addr: address for control frame
615 * @control: control byte including PF bit
616 *
617 * Format up and transmit a link level command frame.
618 */
619
620static inline void gsm_command(struct gsm_mux *gsm, int addr, int control)
621{
622 gsm_send(gsm, addr, 1, control);
623}
624
625/* Data transmission */
626
627#define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */
628
629/**
630 * gsm_data_alloc - allocate data frame
631 * @gsm: GSM mux
632 * @addr: DLCI address
633 * @len: length excluding header and FCS
634 * @ctrl: control byte
635 *
636 * Allocate a new data buffer for sending frames with data. Space is left
637 * at the front for header bytes but that is treated as an implementation
638 * detail and not for the high level code to use
639 */
640
641static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
642 u8 ctrl)
643{
644 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN,
645 GFP_ATOMIC);
646 if (m == NULL)
647 return NULL;
648 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */
649 m->len = len;
650 m->addr = addr;
651 m->ctrl = ctrl;
652 INIT_LIST_HEAD(&m->list);
653 return m;
654}
655
656/**
657 * gsm_data_kick - poke the queue
658 * @gsm: GSM Mux
659 *
660 * The tty device has called us to indicate that room has appeared in
661 * the transmit queue. Ram more data into the pipe if we have any
662 * If we have been flow-stopped by a CMD_FCOFF, then we can only
663 * send messages on DLCI0 until CMD_FCON
664 *
665 * FIXME: lock against link layer control transmissions
666 */
667
668static void gsm_data_kick(struct gsm_mux *gsm)
669{
670 struct gsm_msg *msg, *nmsg;
671 int len;
672 int skip_sof = 0;
673
674 list_for_each_entry_safe(msg, nmsg, &gsm->tx_list, list) {
675 if (gsm->constipated && msg->addr)
676 continue;
677 if (gsm->encoding != 0) {
678 gsm->txframe[0] = GSM1_SOF;
679 len = gsm_stuff_frame(msg->data,
680 gsm->txframe + 1, msg->len);
681 gsm->txframe[len + 1] = GSM1_SOF;
682 len += 2;
683 } else {
684 gsm->txframe[0] = GSM0_SOF;
685 memcpy(gsm->txframe + 1 , msg->data, msg->len);
686 gsm->txframe[msg->len + 1] = GSM0_SOF;
687 len = msg->len + 2;
688 }
689
690 if (debug & 4)
691 print_hex_dump_bytes("gsm_data_kick: ",
692 DUMP_PREFIX_OFFSET,
693 gsm->txframe, len);
694
695 if (gsm->output(gsm, gsm->txframe + skip_sof,
696 len - skip_sof) < 0)
697 break;
698 /* FIXME: Can eliminate one SOF in many more cases */
699 gsm->tx_bytes -= msg->len;
700 /* For a burst of frames skip the extra SOF within the
701 burst */
702 skip_sof = 1;
703
704 list_del(&msg->list);
705 kfree(msg);
706 }
707}
708
709/**
710 * __gsm_data_queue - queue a UI or UIH frame
711 * @dlci: DLCI sending the data
712 * @msg: message queued
713 *
714 * Add data to the transmit queue and try and get stuff moving
715 * out of the mux tty if not already doing so. The Caller must hold
716 * the gsm tx lock.
717 */
718
719static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
720{
721 struct gsm_mux *gsm = dlci->gsm;
722 u8 *dp = msg->data;
723 u8 *fcs = dp + msg->len;
724
725 /* Fill in the header */
726 if (gsm->encoding == 0) {
727 if (msg->len < 128)
728 *--dp = (msg->len << 1) | EA;
729 else {
730 *--dp = (msg->len >> 7); /* bits 7 - 15 */
731 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */
732 }
733 }
734
735 *--dp = msg->ctrl;
736 if (gsm->initiator)
737 *--dp = (msg->addr << 2) | 2 | EA;
738 else
739 *--dp = (msg->addr << 2) | EA;
740 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp);
741 /* Ugly protocol layering violation */
742 if (msg->ctrl == UI || msg->ctrl == (UI|PF))
743 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len);
744 *fcs = 0xFF - *fcs;
745
746 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl,
747 msg->data, msg->len);
748
749 /* Move the header back and adjust the length, also allow for the FCS
750 now tacked on the end */
751 msg->len += (msg->data - dp) + 1;
752 msg->data = dp;
753
754 /* Add to the actual output queue */
755 list_add_tail(&msg->list, &gsm->tx_list);
756 gsm->tx_bytes += msg->len;
757 gsm_data_kick(gsm);
758}
759
760/**
761 * gsm_data_queue - queue a UI or UIH frame
762 * @dlci: DLCI sending the data
763 * @msg: message queued
764 *
765 * Add data to the transmit queue and try and get stuff moving
766 * out of the mux tty if not already doing so. Take the
767 * the gsm tx lock and dlci lock.
768 */
769
770static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
771{
772 unsigned long flags;
773 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
774 __gsm_data_queue(dlci, msg);
775 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
776}
777
778/**
779 * gsm_dlci_data_output - try and push data out of a DLCI
780 * @gsm: mux
781 * @dlci: the DLCI to pull data from
782 *
783 * Pull data from a DLCI and send it into the transmit queue if there
784 * is data. Keep to the MRU of the mux. This path handles the usual tty
785 * interface which is a byte stream with optional modem data.
786 *
787 * Caller must hold the tx_lock of the mux.
788 */
789
790static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci)
791{
792 struct gsm_msg *msg;
793 u8 *dp;
794 int len, total_size, size;
795 int h = dlci->adaption - 1;
796
797 total_size = 0;
798 while (1) {
799 len = kfifo_len(dlci->fifo);
800 if (len == 0)
801 return total_size;
802
803 /* MTU/MRU count only the data bits */
804 if (len > gsm->mtu)
805 len = gsm->mtu;
806
807 size = len + h;
808
809 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
810 /* FIXME: need a timer or something to kick this so it can't
811 get stuck with no work outstanding and no buffer free */
812 if (msg == NULL)
813 return -ENOMEM;
814 dp = msg->data;
815 switch (dlci->adaption) {
816 case 1: /* Unstructured */
817 break;
818 case 2: /* Unstructed with modem bits.
819 Always one byte as we never send inline break data */
820 *dp++ = gsm_encode_modem(dlci);
821 break;
822 }
823 WARN_ON(kfifo_out_locked(dlci->fifo, dp , len, &dlci->lock) != len);
824 __gsm_data_queue(dlci, msg);
825 total_size += size;
826 }
827 /* Bytes of data we used up */
828 return total_size;
829}
830
831/**
832 * gsm_dlci_data_output_framed - try and push data out of a DLCI
833 * @gsm: mux
834 * @dlci: the DLCI to pull data from
835 *
836 * Pull data from a DLCI and send it into the transmit queue if there
837 * is data. Keep to the MRU of the mux. This path handles framed data
838 * queued as skbuffs to the DLCI.
839 *
840 * Caller must hold the tx_lock of the mux.
841 */
842
843static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
844 struct gsm_dlci *dlci)
845{
846 struct gsm_msg *msg;
847 u8 *dp;
848 int len, size;
849 int last = 0, first = 0;
850 int overhead = 0;
851
852 /* One byte per frame is used for B/F flags */
853 if (dlci->adaption == 4)
854 overhead = 1;
855
856 /* dlci->skb is locked by tx_lock */
857 if (dlci->skb == NULL) {
858 dlci->skb = skb_dequeue_tail(&dlci->skb_list);
859 if (dlci->skb == NULL)
860 return 0;
861 first = 1;
862 }
863 len = dlci->skb->len + overhead;
864
865 /* MTU/MRU count only the data bits */
866 if (len > gsm->mtu) {
867 if (dlci->adaption == 3) {
868 /* Over long frame, bin it */
869 dev_kfree_skb_any(dlci->skb);
870 dlci->skb = NULL;
871 return 0;
872 }
873 len = gsm->mtu;
874 } else
875 last = 1;
876
877 size = len + overhead;
878 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
879
880 /* FIXME: need a timer or something to kick this so it can't
881 get stuck with no work outstanding and no buffer free */
882 if (msg == NULL) {
883 skb_queue_tail(&dlci->skb_list, dlci->skb);
884 dlci->skb = NULL;
885 return -ENOMEM;
886 }
887 dp = msg->data;
888
889 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */
890 /* Flag byte to carry the start/end info */
891 *dp++ = last << 7 | first << 6 | 1; /* EA */
892 len--;
893 }
894 memcpy(dp, dlci->skb->data, len);
895 skb_pull(dlci->skb, len);
896 __gsm_data_queue(dlci, msg);
897 if (last) {
898 dev_kfree_skb_any(dlci->skb);
899 dlci->skb = NULL;
900 }
901 return size;
902}
903
904/**
905 * gsm_dlci_data_sweep - look for data to send
906 * @gsm: the GSM mux
907 *
908 * Sweep the GSM mux channels in priority order looking for ones with
909 * data to send. We could do with optimising this scan a bit. We aim
910 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit
911 * TX_THRESH_LO we get called again
912 *
913 * FIXME: We should round robin between groups and in theory you can
914 * renegotiate DLCI priorities with optional stuff. Needs optimising.
915 */
916
917static void gsm_dlci_data_sweep(struct gsm_mux *gsm)
918{
919 int len;
920 /* Priority ordering: We should do priority with RR of the groups */
921 int i = 1;
922
923 while (i < NUM_DLCI) {
924 struct gsm_dlci *dlci;
925
926 if (gsm->tx_bytes > TX_THRESH_HI)
927 break;
928 dlci = gsm->dlci[i];
929 if (dlci == NULL || dlci->constipated) {
930 i++;
931 continue;
932 }
933 if (dlci->adaption < 3 && !dlci->net)
934 len = gsm_dlci_data_output(gsm, dlci);
935 else
936 len = gsm_dlci_data_output_framed(gsm, dlci);
937 if (len < 0)
938 break;
939 /* DLCI empty - try the next */
940 if (len == 0)
941 i++;
942 }
943}
944
945/**
946 * gsm_dlci_data_kick - transmit if possible
947 * @dlci: DLCI to kick
948 *
949 * Transmit data from this DLCI if the queue is empty. We can't rely on
950 * a tty wakeup except when we filled the pipe so we need to fire off
951 * new data ourselves in other cases.
952 */
953
954static void gsm_dlci_data_kick(struct gsm_dlci *dlci)
955{
956 unsigned long flags;
957 int sweep;
958
959 if (dlci->constipated)
960 return;
961
962 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
963 /* If we have nothing running then we need to fire up */
964 sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO);
965 if (dlci->gsm->tx_bytes == 0) {
966 if (dlci->net)
967 gsm_dlci_data_output_framed(dlci->gsm, dlci);
968 else
969 gsm_dlci_data_output(dlci->gsm, dlci);
970 }
971 if (sweep)
972 gsm_dlci_data_sweep(dlci->gsm);
973 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
974}
975
976/*
977 * Control message processing
978 */
979
980
981/**
982 * gsm_control_reply - send a response frame to a control
983 * @gsm: gsm channel
984 * @cmd: the command to use
985 * @data: data to follow encoded info
986 * @dlen: length of data
987 *
988 * Encode up and queue a UI/UIH frame containing our response.
989 */
990
991static void gsm_control_reply(struct gsm_mux *gsm, int cmd, const u8 *data,
992 int dlen)
993{
994 struct gsm_msg *msg;
995 msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype);
996 if (msg == NULL)
997 return;
998 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */
999 msg->data[1] = (dlen << 1) | EA;
1000 memcpy(msg->data + 2, data, dlen);
1001 gsm_data_queue(gsm->dlci[0], msg);
1002}
1003
1004/**
1005 * gsm_process_modem - process received modem status
1006 * @tty: virtual tty bound to the DLCI
1007 * @dlci: DLCI to affect
1008 * @modem: modem bits (full EA)
1009 *
1010 * Used when a modem control message or line state inline in adaption
1011 * layer 2 is processed. Sort out the local modem state and throttles
1012 */
1013
1014static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
1015 u32 modem, int clen)
1016{
1017 int mlines = 0;
1018 u8 brk = 0;
1019 int fc;
1020
1021 /* The modem status command can either contain one octet (v.24 signals)
1022 or two octets (v.24 signals + break signals). The length field will
1023 either be 2 or 3 respectively. This is specified in section
1024 5.4.6.3.7 of the 27.010 mux spec. */
1025
1026 if (clen == 2)
1027 modem = modem & 0x7f;
1028 else {
1029 brk = modem & 0x7f;
1030 modem = (modem >> 7) & 0x7f;
1031 }
1032
1033 /* Flow control/ready to communicate */
1034 fc = (modem & MDM_FC) || !(modem & MDM_RTR);
1035 if (fc && !dlci->constipated) {
1036 /* Need to throttle our output on this device */
1037 dlci->constipated = 1;
1038 } else if (!fc && dlci->constipated) {
1039 dlci->constipated = 0;
1040 gsm_dlci_data_kick(dlci);
1041 }
1042
1043 /* Map modem bits */
1044 if (modem & MDM_RTC)
1045 mlines |= TIOCM_DSR | TIOCM_DTR;
1046 if (modem & MDM_RTR)
1047 mlines |= TIOCM_RTS | TIOCM_CTS;
1048 if (modem & MDM_IC)
1049 mlines |= TIOCM_RI;
1050 if (modem & MDM_DV)
1051 mlines |= TIOCM_CD;
1052
1053 /* Carrier drop -> hangup */
1054 if (tty) {
1055 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD))
1056 if (!C_CLOCAL(tty))
1057 tty_hangup(tty);
1058 }
1059 if (brk & 0x01)
1060 tty_insert_flip_char(&dlci->port, 0, TTY_BREAK);
1061 dlci->modem_rx = mlines;
1062}
1063
1064/**
1065 * gsm_control_modem - modem status received
1066 * @gsm: GSM channel
1067 * @data: data following command
1068 * @clen: command length
1069 *
1070 * We have received a modem status control message. This is used by
1071 * the GSM mux protocol to pass virtual modem line status and optionally
1072 * to indicate break signals. Unpack it, convert to Linux representation
1073 * and if need be stuff a break message down the tty.
1074 */
1075
1076static void gsm_control_modem(struct gsm_mux *gsm, const u8 *data, int clen)
1077{
1078 unsigned int addr = 0;
1079 unsigned int modem = 0;
1080 unsigned int brk = 0;
1081 struct gsm_dlci *dlci;
1082 int len = clen;
1083 const u8 *dp = data;
1084 struct tty_struct *tty;
1085
1086 while (gsm_read_ea(&addr, *dp++) == 0) {
1087 len--;
1088 if (len == 0)
1089 return;
1090 }
1091 /* Must be at least one byte following the EA */
1092 len--;
1093 if (len <= 0)
1094 return;
1095
1096 addr >>= 1;
1097 /* Closed port, or invalid ? */
1098 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1099 return;
1100 dlci = gsm->dlci[addr];
1101
1102 while (gsm_read_ea(&modem, *dp++) == 0) {
1103 len--;
1104 if (len == 0)
1105 return;
1106 }
1107 len--;
1108 if (len > 0) {
1109 while (gsm_read_ea(&brk, *dp++) == 0) {
1110 len--;
1111 if (len == 0)
1112 return;
1113 }
1114 modem <<= 7;
1115 modem |= (brk & 0x7f);
1116 }
1117 tty = tty_port_tty_get(&dlci->port);
1118 gsm_process_modem(tty, dlci, modem, clen);
1119 if (tty) {
1120 tty_wakeup(tty);
1121 tty_kref_put(tty);
1122 }
1123 gsm_control_reply(gsm, CMD_MSC, data, clen);
1124}
1125
1126/**
1127 * gsm_control_rls - remote line status
1128 * @gsm: GSM channel
1129 * @data: data bytes
1130 * @clen: data length
1131 *
1132 * The modem sends us a two byte message on the control channel whenever
1133 * it wishes to send us an error state from the virtual link. Stuff
1134 * this into the uplink tty if present
1135 */
1136
1137static void gsm_control_rls(struct gsm_mux *gsm, const u8 *data, int clen)
1138{
1139 struct tty_port *port;
1140 unsigned int addr = 0;
1141 u8 bits;
1142 int len = clen;
1143 const u8 *dp = data;
1144
1145 while (gsm_read_ea(&addr, *dp++) == 0) {
1146 len--;
1147 if (len == 0)
1148 return;
1149 }
1150 /* Must be at least one byte following ea */
1151 len--;
1152 if (len <= 0)
1153 return;
1154 addr >>= 1;
1155 /* Closed port, or invalid ? */
1156 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1157 return;
1158 /* No error ? */
1159 bits = *dp;
1160 if ((bits & 1) == 0)
1161 return;
1162
1163 port = &gsm->dlci[addr]->port;
1164
1165 if (bits & 2)
1166 tty_insert_flip_char(port, 0, TTY_OVERRUN);
1167 if (bits & 4)
1168 tty_insert_flip_char(port, 0, TTY_PARITY);
1169 if (bits & 8)
1170 tty_insert_flip_char(port, 0, TTY_FRAME);
1171
1172 tty_flip_buffer_push(port);
1173
1174 gsm_control_reply(gsm, CMD_RLS, data, clen);
1175}
1176
1177static void gsm_dlci_begin_close(struct gsm_dlci *dlci);
1178
1179/**
1180 * gsm_control_message - DLCI 0 control processing
1181 * @gsm: our GSM mux
1182 * @command: the command EA
1183 * @data: data beyond the command/length EAs
1184 * @clen: length
1185 *
1186 * Input processor for control messages from the other end of the link.
1187 * Processes the incoming request and queues a response frame or an
1188 * NSC response if not supported
1189 */
1190
1191static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
1192 const u8 *data, int clen)
1193{
1194 u8 buf[1];
1195 unsigned long flags;
1196
1197 switch (command) {
1198 case CMD_CLD: {
1199 struct gsm_dlci *dlci = gsm->dlci[0];
1200 /* Modem wishes to close down */
1201 if (dlci) {
1202 dlci->dead = 1;
1203 gsm->dead = 1;
1204 gsm_dlci_begin_close(dlci);
1205 }
1206 }
1207 break;
1208 case CMD_TEST:
1209 /* Modem wishes to test, reply with the data */
1210 gsm_control_reply(gsm, CMD_TEST, data, clen);
1211 break;
1212 case CMD_FCON:
1213 /* Modem can accept data again */
1214 gsm->constipated = 0;
1215 gsm_control_reply(gsm, CMD_FCON, NULL, 0);
1216 /* Kick the link in case it is idling */
1217 spin_lock_irqsave(&gsm->tx_lock, flags);
1218 gsm_data_kick(gsm);
1219 spin_unlock_irqrestore(&gsm->tx_lock, flags);
1220 break;
1221 case CMD_FCOFF:
1222 /* Modem wants us to STFU */
1223 gsm->constipated = 1;
1224 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0);
1225 break;
1226 case CMD_MSC:
1227 /* Out of band modem line change indicator for a DLCI */
1228 gsm_control_modem(gsm, data, clen);
1229 break;
1230 case CMD_RLS:
1231 /* Out of band error reception for a DLCI */
1232 gsm_control_rls(gsm, data, clen);
1233 break;
1234 case CMD_PSC:
1235 /* Modem wishes to enter power saving state */
1236 gsm_control_reply(gsm, CMD_PSC, NULL, 0);
1237 break;
1238 /* Optional unsupported commands */
1239 case CMD_PN: /* Parameter negotiation */
1240 case CMD_RPN: /* Remote port negotiation */
1241 case CMD_SNC: /* Service negotiation command */
1242 default:
1243 /* Reply to bad commands with an NSC */
1244 buf[0] = command;
1245 gsm_control_reply(gsm, CMD_NSC, buf, 1);
1246 break;
1247 }
1248}
1249
1250/**
1251 * gsm_control_response - process a response to our control
1252 * @gsm: our GSM mux
1253 * @command: the command (response) EA
1254 * @data: data beyond the command/length EA
1255 * @clen: length
1256 *
1257 * Process a response to an outstanding command. We only allow a single
1258 * control message in flight so this is fairly easy. All the clean up
1259 * is done by the caller, we just update the fields, flag it as done
1260 * and return
1261 */
1262
1263static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
1264 const u8 *data, int clen)
1265{
1266 struct gsm_control *ctrl;
1267 unsigned long flags;
1268
1269 spin_lock_irqsave(&gsm->control_lock, flags);
1270
1271 ctrl = gsm->pending_cmd;
1272 /* Does the reply match our command */
1273 command |= 1;
1274 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) {
1275 /* Our command was replied to, kill the retry timer */
1276 del_timer(&gsm->t2_timer);
1277 gsm->pending_cmd = NULL;
1278 /* Rejected by the other end */
1279 if (command == CMD_NSC)
1280 ctrl->error = -EOPNOTSUPP;
1281 ctrl->done = 1;
1282 wake_up(&gsm->event);
1283 }
1284 spin_unlock_irqrestore(&gsm->control_lock, flags);
1285}
1286
1287/**
1288 * gsm_control_transmit - send control packet
1289 * @gsm: gsm mux
1290 * @ctrl: frame to send
1291 *
1292 * Send out a pending control command (called under control lock)
1293 */
1294
1295static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl)
1296{
1297 struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, gsm->ftype);
1298 if (msg == NULL)
1299 return;
1300 msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */
1301 memcpy(msg->data + 1, ctrl->data, ctrl->len);
1302 gsm_data_queue(gsm->dlci[0], msg);
1303}
1304
1305/**
1306 * gsm_control_retransmit - retransmit a control frame
1307 * @data: pointer to our gsm object
1308 *
1309 * Called off the T2 timer expiry in order to retransmit control frames
1310 * that have been lost in the system somewhere. The control_lock protects
1311 * us from colliding with another sender or a receive completion event.
1312 * In that situation the timer may still occur in a small window but
1313 * gsm->pending_cmd will be NULL and we just let the timer expire.
1314 */
1315
1316static void gsm_control_retransmit(struct timer_list *t)
1317{
1318 struct gsm_mux *gsm = from_timer(gsm, t, t2_timer);
1319 struct gsm_control *ctrl;
1320 unsigned long flags;
1321 spin_lock_irqsave(&gsm->control_lock, flags);
1322 ctrl = gsm->pending_cmd;
1323 if (ctrl) {
1324 gsm->cretries--;
1325 if (gsm->cretries == 0) {
1326 gsm->pending_cmd = NULL;
1327 ctrl->error = -ETIMEDOUT;
1328 ctrl->done = 1;
1329 spin_unlock_irqrestore(&gsm->control_lock, flags);
1330 wake_up(&gsm->event);
1331 return;
1332 }
1333 gsm_control_transmit(gsm, ctrl);
1334 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1335 }
1336 spin_unlock_irqrestore(&gsm->control_lock, flags);
1337}
1338
1339/**
1340 * gsm_control_send - send a control frame on DLCI 0
1341 * @gsm: the GSM channel
1342 * @command: command to send including CR bit
1343 * @data: bytes of data (must be kmalloced)
1344 * @len: length of the block to send
1345 *
1346 * Queue and dispatch a control command. Only one command can be
1347 * active at a time. In theory more can be outstanding but the matching
1348 * gets really complicated so for now stick to one outstanding.
1349 */
1350
1351static struct gsm_control *gsm_control_send(struct gsm_mux *gsm,
1352 unsigned int command, u8 *data, int clen)
1353{
1354 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control),
1355 GFP_KERNEL);
1356 unsigned long flags;
1357 if (ctrl == NULL)
1358 return NULL;
1359retry:
1360 wait_event(gsm->event, gsm->pending_cmd == NULL);
1361 spin_lock_irqsave(&gsm->control_lock, flags);
1362 if (gsm->pending_cmd != NULL) {
1363 spin_unlock_irqrestore(&gsm->control_lock, flags);
1364 goto retry;
1365 }
1366 ctrl->cmd = command;
1367 ctrl->data = data;
1368 ctrl->len = clen;
1369 gsm->pending_cmd = ctrl;
1370
1371 /* If DLCI0 is in ADM mode skip retries, it won't respond */
1372 if (gsm->dlci[0]->mode == DLCI_MODE_ADM)
1373 gsm->cretries = 1;
1374 else
1375 gsm->cretries = gsm->n2;
1376
1377 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1378 gsm_control_transmit(gsm, ctrl);
1379 spin_unlock_irqrestore(&gsm->control_lock, flags);
1380 return ctrl;
1381}
1382
1383/**
1384 * gsm_control_wait - wait for a control to finish
1385 * @gsm: GSM mux
1386 * @control: control we are waiting on
1387 *
1388 * Waits for the control to complete or time out. Frees any used
1389 * resources and returns 0 for success, or an error if the remote
1390 * rejected or ignored the request.
1391 */
1392
1393static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
1394{
1395 int err;
1396 wait_event(gsm->event, control->done == 1);
1397 err = control->error;
1398 kfree(control);
1399 return err;
1400}
1401
1402
1403/*
1404 * DLCI level handling: Needs krefs
1405 */
1406
1407/*
1408 * State transitions and timers
1409 */
1410
1411/**
1412 * gsm_dlci_close - a DLCI has closed
1413 * @dlci: DLCI that closed
1414 *
1415 * Perform processing when moving a DLCI into closed state. If there
1416 * is an attached tty this is hung up
1417 */
1418
1419static void gsm_dlci_close(struct gsm_dlci *dlci)
1420{
1421 del_timer(&dlci->t1);
1422 if (debug & 8)
1423 pr_debug("DLCI %d goes closed.\n", dlci->addr);
1424 dlci->state = DLCI_CLOSED;
1425 if (dlci->addr != 0) {
1426 tty_port_tty_hangup(&dlci->port, false);
1427 kfifo_reset(dlci->fifo);
1428 } else
1429 dlci->gsm->dead = 1;
1430 wake_up(&dlci->gsm->event);
1431 /* A DLCI 0 close is a MUX termination so we need to kick that
1432 back to userspace somehow */
1433}
1434
1435/**
1436 * gsm_dlci_open - a DLCI has opened
1437 * @dlci: DLCI that opened
1438 *
1439 * Perform processing when moving a DLCI into open state.
1440 */
1441
1442static void gsm_dlci_open(struct gsm_dlci *dlci)
1443{
1444 /* Note that SABM UA .. SABM UA first UA lost can mean that we go
1445 open -> open */
1446 del_timer(&dlci->t1);
1447 /* This will let a tty open continue */
1448 dlci->state = DLCI_OPEN;
1449 if (debug & 8)
1450 pr_debug("DLCI %d goes open.\n", dlci->addr);
1451 wake_up(&dlci->gsm->event);
1452}
1453
1454/**
1455 * gsm_dlci_t1 - T1 timer expiry
1456 * @dlci: DLCI that opened
1457 *
1458 * The T1 timer handles retransmits of control frames (essentially of
1459 * SABM and DISC). We resend the command until the retry count runs out
1460 * in which case an opening port goes back to closed and a closing port
1461 * is simply put into closed state (any further frames from the other
1462 * end will get a DM response)
1463 *
1464 * Some control dlci can stay in ADM mode with other dlci working just
1465 * fine. In that case we can just keep the control dlci open after the
1466 * DLCI_OPENING retries time out.
1467 */
1468
1469static void gsm_dlci_t1(struct timer_list *t)
1470{
1471 struct gsm_dlci *dlci = from_timer(dlci, t, t1);
1472 struct gsm_mux *gsm = dlci->gsm;
1473
1474 switch (dlci->state) {
1475 case DLCI_OPENING:
1476 dlci->retries--;
1477 if (dlci->retries) {
1478 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1479 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1480 } else if (!dlci->addr && gsm->control == (DM | PF)) {
1481 if (debug & 8)
1482 pr_info("DLCI %d opening in ADM mode.\n",
1483 dlci->addr);
1484 dlci->mode = DLCI_MODE_ADM;
1485 gsm_dlci_open(dlci);
1486 } else {
1487 gsm_dlci_close(dlci);
1488 }
1489
1490 break;
1491 case DLCI_CLOSING:
1492 dlci->retries--;
1493 if (dlci->retries) {
1494 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1495 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1496 } else
1497 gsm_dlci_close(dlci);
1498 break;
1499 }
1500}
1501
1502/**
1503 * gsm_dlci_begin_open - start channel open procedure
1504 * @dlci: DLCI to open
1505 *
1506 * Commence opening a DLCI from the Linux side. We issue SABM messages
1507 * to the modem which should then reply with a UA or ADM, at which point
1508 * we will move into open state. Opening is done asynchronously with retry
1509 * running off timers and the responses.
1510 */
1511
1512static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
1513{
1514 struct gsm_mux *gsm = dlci->gsm;
1515 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING)
1516 return;
1517 dlci->retries = gsm->n2;
1518 dlci->state = DLCI_OPENING;
1519 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1520 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1521}
1522
1523/**
1524 * gsm_dlci_begin_close - start channel open procedure
1525 * @dlci: DLCI to open
1526 *
1527 * Commence closing a DLCI from the Linux side. We issue DISC messages
1528 * to the modem which should then reply with a UA, at which point we
1529 * will move into closed state. Closing is done asynchronously with retry
1530 * off timers. We may also receive a DM reply from the other end which
1531 * indicates the channel was already closed.
1532 */
1533
1534static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
1535{
1536 struct gsm_mux *gsm = dlci->gsm;
1537 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
1538 return;
1539 dlci->retries = gsm->n2;
1540 dlci->state = DLCI_CLOSING;
1541 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1542 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1543}
1544
1545/**
1546 * gsm_dlci_data - data arrived
1547 * @dlci: channel
1548 * @data: block of bytes received
1549 * @len: length of received block
1550 *
1551 * A UI or UIH frame has arrived which contains data for a channel
1552 * other than the control channel. If the relevant virtual tty is
1553 * open we shovel the bits down it, if not we drop them.
1554 */
1555
1556static void gsm_dlci_data(struct gsm_dlci *dlci, const u8 *data, int clen)
1557{
1558 /* krefs .. */
1559 struct tty_port *port = &dlci->port;
1560 struct tty_struct *tty;
1561 unsigned int modem = 0;
1562 int len = clen;
1563
1564 if (debug & 16)
1565 pr_debug("%d bytes for tty\n", len);
1566 switch (dlci->adaption) {
1567 /* Unsupported types */
1568 case 4: /* Packetised interruptible data */
1569 break;
1570 case 3: /* Packetised uininterruptible voice/data */
1571 break;
1572 case 2: /* Asynchronous serial with line state in each frame */
1573 while (gsm_read_ea(&modem, *data++) == 0) {
1574 len--;
1575 if (len == 0)
1576 return;
1577 }
1578 tty = tty_port_tty_get(port);
1579 if (tty) {
1580 gsm_process_modem(tty, dlci, modem, clen);
1581 tty_kref_put(tty);
1582 }
1583 /* Fall through */
1584 case 1: /* Line state will go via DLCI 0 controls only */
1585 default:
1586 tty_insert_flip_string(port, data, len);
1587 tty_flip_buffer_push(port);
1588 }
1589}
1590
1591/**
1592 * gsm_dlci_control - data arrived on control channel
1593 * @dlci: channel
1594 * @data: block of bytes received
1595 * @len: length of received block
1596 *
1597 * A UI or UIH frame has arrived which contains data for DLCI 0 the
1598 * control channel. This should contain a command EA followed by
1599 * control data bytes. The command EA contains a command/response bit
1600 * and we divide up the work accordingly.
1601 */
1602
1603static void gsm_dlci_command(struct gsm_dlci *dlci, const u8 *data, int len)
1604{
1605 /* See what command is involved */
1606 unsigned int command = 0;
1607 while (len-- > 0) {
1608 if (gsm_read_ea(&command, *data++) == 1) {
1609 int clen = *data++;
1610 len--;
1611 /* FIXME: this is properly an EA */
1612 clen >>= 1;
1613 /* Malformed command ? */
1614 if (clen > len)
1615 return;
1616 if (command & 1)
1617 gsm_control_message(dlci->gsm, command,
1618 data, clen);
1619 else
1620 gsm_control_response(dlci->gsm, command,
1621 data, clen);
1622 return;
1623 }
1624 }
1625}
1626
1627/*
1628 * Allocate/Free DLCI channels
1629 */
1630
1631/**
1632 * gsm_dlci_alloc - allocate a DLCI
1633 * @gsm: GSM mux
1634 * @addr: address of the DLCI
1635 *
1636 * Allocate and install a new DLCI object into the GSM mux.
1637 *
1638 * FIXME: review locking races
1639 */
1640
1641static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
1642{
1643 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC);
1644 if (dlci == NULL)
1645 return NULL;
1646 spin_lock_init(&dlci->lock);
1647 mutex_init(&dlci->mutex);
1648 dlci->fifo = &dlci->_fifo;
1649 if (kfifo_alloc(&dlci->_fifo, 4096, GFP_KERNEL) < 0) {
1650 kfree(dlci);
1651 return NULL;
1652 }
1653
1654 skb_queue_head_init(&dlci->skb_list);
1655 timer_setup(&dlci->t1, gsm_dlci_t1, 0);
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_hangup(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 /* Fall 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
2022static int gsm_disconnect(struct gsm_mux *gsm)
2023{
2024 struct gsm_dlci *dlci = gsm->dlci[0];
2025 struct gsm_control *gc;
2026
2027 if (!dlci)
2028 return 0;
2029
2030 /* In theory disconnecting DLCI 0 is sufficient but for some
2031 modems this is apparently not the case. */
2032 gc = gsm_control_send(gsm, CMD_CLD, NULL, 0);
2033 if (gc)
2034 gsm_control_wait(gsm, gc);
2035
2036 del_timer_sync(&gsm->t2_timer);
2037 /* Now we are sure T2 has stopped */
2038
2039 gsm_dlci_begin_close(dlci);
2040 wait_event_interruptible(gsm->event,
2041 dlci->state == DLCI_CLOSED);
2042
2043 if (signal_pending(current))
2044 return -EINTR;
2045
2046 return 0;
2047}
2048
2049/**
2050 * gsm_cleanup_mux - generic GSM protocol cleanup
2051 * @gsm: our mux
2052 *
2053 * Clean up the bits of the mux which are the same for all framing
2054 * protocols. Remove the mux from the mux table, stop all the timers
2055 * and then shut down each device hanging up the channels as we go.
2056 */
2057
2058static void gsm_cleanup_mux(struct gsm_mux *gsm)
2059{
2060 int i;
2061 struct gsm_dlci *dlci = gsm->dlci[0];
2062 struct gsm_msg *txq, *ntxq;
2063
2064 gsm->dead = 1;
2065
2066 spin_lock(&gsm_mux_lock);
2067 for (i = 0; i < MAX_MUX; i++) {
2068 if (gsm_mux[i] == gsm) {
2069 gsm_mux[i] = NULL;
2070 break;
2071 }
2072 }
2073 spin_unlock(&gsm_mux_lock);
2074 /* open failed before registering => nothing to do */
2075 if (i == MAX_MUX)
2076 return;
2077
2078 del_timer_sync(&gsm->t2_timer);
2079 /* Now we are sure T2 has stopped */
2080 if (dlci)
2081 dlci->dead = 1;
2082
2083 /* Free up any link layer users */
2084 mutex_lock(&gsm->mutex);
2085 for (i = 0; i < NUM_DLCI; i++)
2086 if (gsm->dlci[i])
2087 gsm_dlci_release(gsm->dlci[i]);
2088 mutex_unlock(&gsm->mutex);
2089 /* Now wipe the queues */
2090 list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list)
2091 kfree(txq);
2092 INIT_LIST_HEAD(&gsm->tx_list);
2093}
2094
2095/**
2096 * gsm_activate_mux - generic GSM setup
2097 * @gsm: our mux
2098 *
2099 * Set up the bits of the mux which are the same for all framing
2100 * protocols. Add the mux to the mux table so it can be opened and
2101 * finally kick off connecting to DLCI 0 on the modem.
2102 */
2103
2104static int gsm_activate_mux(struct gsm_mux *gsm)
2105{
2106 struct gsm_dlci *dlci;
2107 int i = 0;
2108
2109 timer_setup(&gsm->t2_timer, gsm_control_retransmit, 0);
2110 init_waitqueue_head(&gsm->event);
2111 spin_lock_init(&gsm->control_lock);
2112 spin_lock_init(&gsm->tx_lock);
2113
2114 if (gsm->encoding == 0)
2115 gsm->receive = gsm0_receive;
2116 else
2117 gsm->receive = gsm1_receive;
2118 gsm->error = gsm_error;
2119
2120 spin_lock(&gsm_mux_lock);
2121 for (i = 0; i < MAX_MUX; i++) {
2122 if (gsm_mux[i] == NULL) {
2123 gsm->num = i;
2124 gsm_mux[i] = gsm;
2125 break;
2126 }
2127 }
2128 spin_unlock(&gsm_mux_lock);
2129 if (i == MAX_MUX)
2130 return -EBUSY;
2131
2132 dlci = gsm_dlci_alloc(gsm, 0);
2133 if (dlci == NULL)
2134 return -ENOMEM;
2135 gsm->dead = 0; /* Tty opens are now permissible */
2136 return 0;
2137}
2138
2139/**
2140 * gsm_free_mux - free up a mux
2141 * @mux: mux to free
2142 *
2143 * Dispose of allocated resources for a dead mux
2144 */
2145static void gsm_free_mux(struct gsm_mux *gsm)
2146{
2147 kfree(gsm->txframe);
2148 kfree(gsm->buf);
2149 kfree(gsm);
2150}
2151
2152/**
2153 * gsm_free_muxr - free up a mux
2154 * @mux: mux to free
2155 *
2156 * Dispose of allocated resources for a dead mux
2157 */
2158static void gsm_free_muxr(struct kref *ref)
2159{
2160 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref);
2161 gsm_free_mux(gsm);
2162}
2163
2164static inline void mux_get(struct gsm_mux *gsm)
2165{
2166 kref_get(&gsm->ref);
2167}
2168
2169static inline void mux_put(struct gsm_mux *gsm)
2170{
2171 kref_put(&gsm->ref, gsm_free_muxr);
2172}
2173
2174static inline unsigned int mux_num_to_base(struct gsm_mux *gsm)
2175{
2176 return gsm->num * NUM_DLCI;
2177}
2178
2179static inline unsigned int mux_line_to_num(unsigned int line)
2180{
2181 return line / NUM_DLCI;
2182}
2183
2184/**
2185 * gsm_alloc_mux - allocate a mux
2186 *
2187 * Creates a new mux ready for activation.
2188 */
2189
2190static struct gsm_mux *gsm_alloc_mux(void)
2191{
2192 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
2193 if (gsm == NULL)
2194 return NULL;
2195 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL);
2196 if (gsm->buf == NULL) {
2197 kfree(gsm);
2198 return NULL;
2199 }
2200 gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL);
2201 if (gsm->txframe == NULL) {
2202 kfree(gsm->buf);
2203 kfree(gsm);
2204 return NULL;
2205 }
2206 spin_lock_init(&gsm->lock);
2207 mutex_init(&gsm->mutex);
2208 kref_init(&gsm->ref);
2209 INIT_LIST_HEAD(&gsm->tx_list);
2210
2211 gsm->t1 = T1;
2212 gsm->t2 = T2;
2213 gsm->n2 = N2;
2214 gsm->ftype = UIH;
2215 gsm->adaption = 1;
2216 gsm->encoding = 1;
2217 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
2218 gsm->mtu = 64;
2219 gsm->dead = 1; /* Avoid early tty opens */
2220
2221 return gsm;
2222}
2223
2224static void gsm_copy_config_values(struct gsm_mux *gsm,
2225 struct gsm_config *c)
2226{
2227 memset(c, 0, sizeof(*c));
2228 c->adaption = gsm->adaption;
2229 c->encapsulation = gsm->encoding;
2230 c->initiator = gsm->initiator;
2231 c->t1 = gsm->t1;
2232 c->t2 = gsm->t2;
2233 c->t3 = 0; /* Not supported */
2234 c->n2 = gsm->n2;
2235 if (gsm->ftype == UIH)
2236 c->i = 1;
2237 else
2238 c->i = 2;
2239 pr_debug("Ftype %d i %d\n", gsm->ftype, c->i);
2240 c->mru = gsm->mru;
2241 c->mtu = gsm->mtu;
2242 c->k = 0;
2243}
2244
2245static int gsm_config(struct gsm_mux *gsm, struct gsm_config *c)
2246{
2247 int need_close = 0;
2248 int need_restart = 0;
2249
2250 /* Stuff we don't support yet - UI or I frame transport, windowing */
2251 if ((c->adaption != 1 && c->adaption != 2) || c->k)
2252 return -EOPNOTSUPP;
2253 /* Check the MRU/MTU range looks sane */
2254 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8)
2255 return -EINVAL;
2256 if (c->n2 < 3)
2257 return -EINVAL;
2258 if (c->encapsulation > 1) /* Basic, advanced, no I */
2259 return -EINVAL;
2260 if (c->initiator > 1)
2261 return -EINVAL;
2262 if (c->i == 0 || c->i > 2) /* UIH and UI only */
2263 return -EINVAL;
2264 /*
2265 * See what is needed for reconfiguration
2266 */
2267
2268 /* Timing fields */
2269 if (c->t1 != 0 && c->t1 != gsm->t1)
2270 need_restart = 1;
2271 if (c->t2 != 0 && c->t2 != gsm->t2)
2272 need_restart = 1;
2273 if (c->encapsulation != gsm->encoding)
2274 need_restart = 1;
2275 if (c->adaption != gsm->adaption)
2276 need_restart = 1;
2277 /* Requires care */
2278 if (c->initiator != gsm->initiator)
2279 need_close = 1;
2280 if (c->mru != gsm->mru)
2281 need_restart = 1;
2282 if (c->mtu != gsm->mtu)
2283 need_restart = 1;
2284
2285 /*
2286 * Close down what is needed, restart and initiate the new
2287 * configuration
2288 */
2289
2290 if (need_close || need_restart) {
2291 int ret;
2292
2293 ret = gsm_disconnect(gsm);
2294
2295 if (ret)
2296 return ret;
2297 }
2298 if (need_restart)
2299 gsm_cleanup_mux(gsm);
2300
2301 gsm->initiator = c->initiator;
2302 gsm->mru = c->mru;
2303 gsm->mtu = c->mtu;
2304 gsm->encoding = c->encapsulation;
2305 gsm->adaption = c->adaption;
2306 gsm->n2 = c->n2;
2307
2308 if (c->i == 1)
2309 gsm->ftype = UIH;
2310 else if (c->i == 2)
2311 gsm->ftype = UI;
2312
2313 if (c->t1)
2314 gsm->t1 = c->t1;
2315 if (c->t2)
2316 gsm->t2 = c->t2;
2317
2318 /*
2319 * FIXME: We need to separate activation/deactivation from adding
2320 * and removing from the mux array
2321 */
2322 if (need_restart)
2323 gsm_activate_mux(gsm);
2324 if (gsm->initiator && need_close)
2325 gsm_dlci_begin_open(gsm->dlci[0]);
2326 return 0;
2327}
2328
2329/**
2330 * gsmld_output - write to link
2331 * @gsm: our mux
2332 * @data: bytes to output
2333 * @len: size
2334 *
2335 * Write a block of data from the GSM mux to the data channel. This
2336 * will eventually be serialized from above but at the moment isn't.
2337 */
2338
2339static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
2340{
2341 if (tty_write_room(gsm->tty) < len) {
2342 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
2343 return -ENOSPC;
2344 }
2345 if (debug & 4)
2346 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET,
2347 data, len);
2348 gsm->tty->ops->write(gsm->tty, data, len);
2349 return len;
2350}
2351
2352/**
2353 * gsmld_attach_gsm - mode set up
2354 * @tty: our tty structure
2355 * @gsm: our mux
2356 *
2357 * Set up the MUX for basic mode and commence connecting to the
2358 * modem. Currently called from the line discipline set up but
2359 * will need moving to an ioctl path.
2360 */
2361
2362static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2363{
2364 unsigned int base;
2365 int ret, i;
2366
2367 gsm->tty = tty_kref_get(tty);
2368 gsm->output = gsmld_output;
2369 ret = gsm_activate_mux(gsm);
2370 if (ret != 0)
2371 tty_kref_put(gsm->tty);
2372 else {
2373 /* Don't register device 0 - this is the control channel and not
2374 a usable tty interface */
2375 base = mux_num_to_base(gsm); /* Base for this MUX */
2376 for (i = 1; i < NUM_DLCI; i++)
2377 tty_register_device(gsm_tty_driver, base + i, NULL);
2378 }
2379 return ret;
2380}
2381
2382
2383/**
2384 * gsmld_detach_gsm - stop doing 0710 mux
2385 * @tty: tty attached to the mux
2386 * @gsm: mux
2387 *
2388 * Shutdown and then clean up the resources used by the line discipline
2389 */
2390
2391static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2392{
2393 unsigned int base = mux_num_to_base(gsm); /* Base for this MUX */
2394 int i;
2395
2396 WARN_ON(tty != gsm->tty);
2397 for (i = 1; i < NUM_DLCI; i++)
2398 tty_unregister_device(gsm_tty_driver, base + i);
2399 gsm_cleanup_mux(gsm);
2400 tty_kref_put(gsm->tty);
2401 gsm->tty = NULL;
2402}
2403
2404static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
2405 char *fp, int count)
2406{
2407 struct gsm_mux *gsm = tty->disc_data;
2408 const unsigned char *dp;
2409 char *f;
2410 int i;
2411 char flags = TTY_NORMAL;
2412
2413 if (debug & 4)
2414 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET,
2415 cp, count);
2416
2417 for (i = count, dp = cp, f = fp; i; i--, dp++) {
2418 if (f)
2419 flags = *f++;
2420 switch (flags) {
2421 case TTY_NORMAL:
2422 gsm->receive(gsm, *dp);
2423 break;
2424 case TTY_OVERRUN:
2425 case TTY_BREAK:
2426 case TTY_PARITY:
2427 case TTY_FRAME:
2428 gsm->error(gsm, *dp, flags);
2429 break;
2430 default:
2431 WARN_ONCE(1, "%s: unknown flag %d\n",
2432 tty_name(tty), flags);
2433 break;
2434 }
2435 }
2436 /* FASYNC if needed ? */
2437 /* If clogged call tty_throttle(tty); */
2438}
2439
2440/**
2441 * gsmld_flush_buffer - clean input queue
2442 * @tty: terminal device
2443 *
2444 * Flush the input buffer. Called when the line discipline is
2445 * being closed, when the tty layer wants the buffer flushed (eg
2446 * at hangup).
2447 */
2448
2449static void gsmld_flush_buffer(struct tty_struct *tty)
2450{
2451}
2452
2453/**
2454 * gsmld_close - close the ldisc for this tty
2455 * @tty: device
2456 *
2457 * Called from the terminal layer when this line discipline is
2458 * being shut down, either because of a close or becsuse of a
2459 * discipline change. The function will not be called while other
2460 * ldisc methods are in progress.
2461 */
2462
2463static void gsmld_close(struct tty_struct *tty)
2464{
2465 struct gsm_mux *gsm = tty->disc_data;
2466
2467 gsmld_detach_gsm(tty, gsm);
2468
2469 gsmld_flush_buffer(tty);
2470 /* Do other clean up here */
2471 mux_put(gsm);
2472}
2473
2474/**
2475 * gsmld_open - open an ldisc
2476 * @tty: terminal to open
2477 *
2478 * Called when this line discipline is being attached to the
2479 * terminal device. Can sleep. Called serialized so that no
2480 * other events will occur in parallel. No further open will occur
2481 * until a close.
2482 */
2483
2484static int gsmld_open(struct tty_struct *tty)
2485{
2486 struct gsm_mux *gsm;
2487 int ret;
2488
2489 if (tty->ops->write == NULL)
2490 return -EINVAL;
2491
2492 /* Attach our ldisc data */
2493 gsm = gsm_alloc_mux();
2494 if (gsm == NULL)
2495 return -ENOMEM;
2496
2497 tty->disc_data = gsm;
2498 tty->receive_room = 65536;
2499
2500 /* Attach the initial passive connection */
2501 gsm->encoding = 1;
2502
2503 ret = gsmld_attach_gsm(tty, gsm);
2504 if (ret != 0) {
2505 gsm_cleanup_mux(gsm);
2506 mux_put(gsm);
2507 }
2508 return ret;
2509}
2510
2511/**
2512 * gsmld_write_wakeup - asynchronous I/O notifier
2513 * @tty: tty device
2514 *
2515 * Required for the ptys, serial driver etc. since processes
2516 * that attach themselves to the master and rely on ASYNC
2517 * IO must be woken up
2518 */
2519
2520static void gsmld_write_wakeup(struct tty_struct *tty)
2521{
2522 struct gsm_mux *gsm = tty->disc_data;
2523 unsigned long flags;
2524
2525 /* Queue poll */
2526 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2527 spin_lock_irqsave(&gsm->tx_lock, flags);
2528 gsm_data_kick(gsm);
2529 if (gsm->tx_bytes < TX_THRESH_LO) {
2530 gsm_dlci_data_sweep(gsm);
2531 }
2532 spin_unlock_irqrestore(&gsm->tx_lock, flags);
2533}
2534
2535/**
2536 * gsmld_read - read function for tty
2537 * @tty: tty device
2538 * @file: file object
2539 * @buf: userspace buffer pointer
2540 * @nr: size of I/O
2541 *
2542 * Perform reads for the line discipline. We are guaranteed that the
2543 * line discipline will not be closed under us but we may get multiple
2544 * parallel readers and must handle this ourselves. We may also get
2545 * a hangup. Always called in user context, may sleep.
2546 *
2547 * This code must be sure never to sleep through a hangup.
2548 */
2549
2550static ssize_t gsmld_read(struct tty_struct *tty, struct file *file,
2551 unsigned char __user *buf, size_t nr)
2552{
2553 return -EOPNOTSUPP;
2554}
2555
2556/**
2557 * gsmld_write - write function for tty
2558 * @tty: tty device
2559 * @file: file object
2560 * @buf: userspace buffer pointer
2561 * @nr: size of I/O
2562 *
2563 * Called when the owner of the device wants to send a frame
2564 * itself (or some other control data). The data is transferred
2565 * as-is and must be properly framed and checksummed as appropriate
2566 * by userspace. Frames are either sent whole or not at all as this
2567 * avoids pain user side.
2568 */
2569
2570static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
2571 const unsigned char *buf, size_t nr)
2572{
2573 int space = tty_write_room(tty);
2574 if (space >= nr)
2575 return tty->ops->write(tty, buf, nr);
2576 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2577 return -ENOBUFS;
2578}
2579
2580/**
2581 * gsmld_poll - poll method for N_GSM0710
2582 * @tty: terminal device
2583 * @file: file accessing it
2584 * @wait: poll table
2585 *
2586 * Called when the line discipline is asked to poll() for data or
2587 * for special events. This code is not serialized with respect to
2588 * other events save open/close.
2589 *
2590 * This code must be sure never to sleep through a hangup.
2591 * Called without the kernel lock held - fine
2592 */
2593
2594static __poll_t gsmld_poll(struct tty_struct *tty, struct file *file,
2595 poll_table *wait)
2596{
2597 __poll_t mask = 0;
2598 struct gsm_mux *gsm = tty->disc_data;
2599
2600 poll_wait(file, &tty->read_wait, wait);
2601 poll_wait(file, &tty->write_wait, wait);
2602 if (tty_hung_up_p(file))
2603 mask |= EPOLLHUP;
2604 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
2605 mask |= EPOLLOUT | EPOLLWRNORM;
2606 if (gsm->dead)
2607 mask |= EPOLLHUP;
2608 return mask;
2609}
2610
2611static int gsmld_ioctl(struct tty_struct *tty, struct file *file,
2612 unsigned int cmd, unsigned long arg)
2613{
2614 struct gsm_config c;
2615 struct gsm_mux *gsm = tty->disc_data;
2616 unsigned int base;
2617
2618 switch (cmd) {
2619 case GSMIOC_GETCONF:
2620 gsm_copy_config_values(gsm, &c);
2621 if (copy_to_user((void *)arg, &c, sizeof(c)))
2622 return -EFAULT;
2623 return 0;
2624 case GSMIOC_SETCONF:
2625 if (copy_from_user(&c, (void *)arg, sizeof(c)))
2626 return -EFAULT;
2627 return gsm_config(gsm, &c);
2628 case GSMIOC_GETFIRST:
2629 base = mux_num_to_base(gsm);
2630 return put_user(base + 1, (__u32 __user *)arg);
2631 default:
2632 return n_tty_ioctl_helper(tty, file, cmd, arg);
2633 }
2634}
2635
2636/*
2637 * Network interface
2638 *
2639 */
2640
2641static int gsm_mux_net_open(struct net_device *net)
2642{
2643 pr_debug("%s called\n", __func__);
2644 netif_start_queue(net);
2645 return 0;
2646}
2647
2648static int gsm_mux_net_close(struct net_device *net)
2649{
2650 netif_stop_queue(net);
2651 return 0;
2652}
2653
2654static void dlci_net_free(struct gsm_dlci *dlci)
2655{
2656 if (!dlci->net) {
2657 WARN_ON(1);
2658 return;
2659 }
2660 dlci->adaption = dlci->prev_adaption;
2661 dlci->data = dlci->prev_data;
2662 free_netdev(dlci->net);
2663 dlci->net = NULL;
2664}
2665static void net_free(struct kref *ref)
2666{
2667 struct gsm_mux_net *mux_net;
2668 struct gsm_dlci *dlci;
2669
2670 mux_net = container_of(ref, struct gsm_mux_net, ref);
2671 dlci = mux_net->dlci;
2672
2673 if (dlci->net) {
2674 unregister_netdev(dlci->net);
2675 dlci_net_free(dlci);
2676 }
2677}
2678
2679static inline void muxnet_get(struct gsm_mux_net *mux_net)
2680{
2681 kref_get(&mux_net->ref);
2682}
2683
2684static inline void muxnet_put(struct gsm_mux_net *mux_net)
2685{
2686 kref_put(&mux_net->ref, net_free);
2687}
2688
2689static netdev_tx_t gsm_mux_net_start_xmit(struct sk_buff *skb,
2690 struct net_device *net)
2691{
2692 struct gsm_mux_net *mux_net = netdev_priv(net);
2693 struct gsm_dlci *dlci = mux_net->dlci;
2694 muxnet_get(mux_net);
2695
2696 skb_queue_head(&dlci->skb_list, skb);
2697 net->stats.tx_packets++;
2698 net->stats.tx_bytes += skb->len;
2699 gsm_dlci_data_kick(dlci);
2700 /* And tell the kernel when the last transmit started. */
2701 netif_trans_update(net);
2702 muxnet_put(mux_net);
2703 return NETDEV_TX_OK;
2704}
2705
2706/* called when a packet did not ack after watchdogtimeout */
2707static void gsm_mux_net_tx_timeout(struct net_device *net)
2708{
2709 /* Tell syslog we are hosed. */
2710 dev_dbg(&net->dev, "Tx timed out.\n");
2711
2712 /* Update statistics */
2713 net->stats.tx_errors++;
2714}
2715
2716static void gsm_mux_rx_netchar(struct gsm_dlci *dlci,
2717 const unsigned char *in_buf, int size)
2718{
2719 struct net_device *net = dlci->net;
2720 struct sk_buff *skb;
2721 struct gsm_mux_net *mux_net = netdev_priv(net);
2722 muxnet_get(mux_net);
2723
2724 /* Allocate an sk_buff */
2725 skb = dev_alloc_skb(size + NET_IP_ALIGN);
2726 if (!skb) {
2727 /* We got no receive buffer. */
2728 net->stats.rx_dropped++;
2729 muxnet_put(mux_net);
2730 return;
2731 }
2732 skb_reserve(skb, NET_IP_ALIGN);
2733 skb_put_data(skb, in_buf, size);
2734
2735 skb->dev = net;
2736 skb->protocol = htons(ETH_P_IP);
2737
2738 /* Ship it off to the kernel */
2739 netif_rx(skb);
2740
2741 /* update out statistics */
2742 net->stats.rx_packets++;
2743 net->stats.rx_bytes += size;
2744 muxnet_put(mux_net);
2745 return;
2746}
2747
2748static void gsm_mux_net_init(struct net_device *net)
2749{
2750 static const struct net_device_ops gsm_netdev_ops = {
2751 .ndo_open = gsm_mux_net_open,
2752 .ndo_stop = gsm_mux_net_close,
2753 .ndo_start_xmit = gsm_mux_net_start_xmit,
2754 .ndo_tx_timeout = gsm_mux_net_tx_timeout,
2755 };
2756
2757 net->netdev_ops = &gsm_netdev_ops;
2758
2759 /* fill in the other fields */
2760 net->watchdog_timeo = GSM_NET_TX_TIMEOUT;
2761 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
2762 net->type = ARPHRD_NONE;
2763 net->tx_queue_len = 10;
2764}
2765
2766
2767/* caller holds the dlci mutex */
2768static void gsm_destroy_network(struct gsm_dlci *dlci)
2769{
2770 struct gsm_mux_net *mux_net;
2771
2772 pr_debug("destroy network interface");
2773 if (!dlci->net)
2774 return;
2775 mux_net = netdev_priv(dlci->net);
2776 muxnet_put(mux_net);
2777}
2778
2779
2780/* caller holds the dlci mutex */
2781static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
2782{
2783 char *netname;
2784 int retval = 0;
2785 struct net_device *net;
2786 struct gsm_mux_net *mux_net;
2787
2788 if (!capable(CAP_NET_ADMIN))
2789 return -EPERM;
2790
2791 /* Already in a non tty mode */
2792 if (dlci->adaption > 2)
2793 return -EBUSY;
2794
2795 if (nc->protocol != htons(ETH_P_IP))
2796 return -EPROTONOSUPPORT;
2797
2798 if (nc->adaption != 3 && nc->adaption != 4)
2799 return -EPROTONOSUPPORT;
2800
2801 pr_debug("create network interface");
2802
2803 netname = "gsm%d";
2804 if (nc->if_name[0] != '\0')
2805 netname = nc->if_name;
2806 net = alloc_netdev(sizeof(struct gsm_mux_net), netname,
2807 NET_NAME_UNKNOWN, gsm_mux_net_init);
2808 if (!net) {
2809 pr_err("alloc_netdev failed");
2810 return -ENOMEM;
2811 }
2812 net->mtu = dlci->gsm->mtu;
2813 net->min_mtu = 8;
2814 net->max_mtu = dlci->gsm->mtu;
2815 mux_net = netdev_priv(net);
2816 mux_net->dlci = dlci;
2817 kref_init(&mux_net->ref);
2818 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */
2819
2820 /* reconfigure dlci for network */
2821 dlci->prev_adaption = dlci->adaption;
2822 dlci->prev_data = dlci->data;
2823 dlci->adaption = nc->adaption;
2824 dlci->data = gsm_mux_rx_netchar;
2825 dlci->net = net;
2826
2827 pr_debug("register netdev");
2828 retval = register_netdev(net);
2829 if (retval) {
2830 pr_err("network register fail %d\n", retval);
2831 dlci_net_free(dlci);
2832 return retval;
2833 }
2834 return net->ifindex; /* return network index */
2835}
2836
2837/* Line discipline for real tty */
2838static struct tty_ldisc_ops tty_ldisc_packet = {
2839 .owner = THIS_MODULE,
2840 .magic = TTY_LDISC_MAGIC,
2841 .name = "n_gsm",
2842 .open = gsmld_open,
2843 .close = gsmld_close,
2844 .flush_buffer = gsmld_flush_buffer,
2845 .read = gsmld_read,
2846 .write = gsmld_write,
2847 .ioctl = gsmld_ioctl,
2848 .poll = gsmld_poll,
2849 .receive_buf = gsmld_receive_buf,
2850 .write_wakeup = gsmld_write_wakeup
2851};
2852
2853/*
2854 * Virtual tty side
2855 */
2856
2857#define TX_SIZE 512
2858
2859static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk)
2860{
2861 u8 modembits[5];
2862 struct gsm_control *ctrl;
2863 int len = 2;
2864
2865 if (brk)
2866 len++;
2867
2868 modembits[0] = len << 1 | EA; /* Data bytes */
2869 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */
2870 modembits[2] = gsm_encode_modem(dlci) << 1 | EA;
2871 if (brk)
2872 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */
2873 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1);
2874 if (ctrl == NULL)
2875 return -ENOMEM;
2876 return gsm_control_wait(dlci->gsm, ctrl);
2877}
2878
2879static int gsm_carrier_raised(struct tty_port *port)
2880{
2881 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2882 struct gsm_mux *gsm = dlci->gsm;
2883
2884 /* Not yet open so no carrier info */
2885 if (dlci->state != DLCI_OPEN)
2886 return 0;
2887 if (debug & 2)
2888 return 1;
2889
2890 /*
2891 * Basic mode with control channel in ADM mode may not respond
2892 * to CMD_MSC at all and modem_rx is empty.
2893 */
2894 if (gsm->encoding == 0 && gsm->dlci[0]->mode == DLCI_MODE_ADM &&
2895 !dlci->modem_rx)
2896 return 1;
2897
2898 return dlci->modem_rx & TIOCM_CD;
2899}
2900
2901static void gsm_dtr_rts(struct tty_port *port, int onoff)
2902{
2903 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2904 unsigned int modem_tx = dlci->modem_tx;
2905 if (onoff)
2906 modem_tx |= TIOCM_DTR | TIOCM_RTS;
2907 else
2908 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
2909 if (modem_tx != dlci->modem_tx) {
2910 dlci->modem_tx = modem_tx;
2911 gsmtty_modem_update(dlci, 0);
2912 }
2913}
2914
2915static const struct tty_port_operations gsm_port_ops = {
2916 .carrier_raised = gsm_carrier_raised,
2917 .dtr_rts = gsm_dtr_rts,
2918 .destruct = gsm_dlci_free,
2919};
2920
2921static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty)
2922{
2923 struct gsm_mux *gsm;
2924 struct gsm_dlci *dlci;
2925 unsigned int line = tty->index;
2926 unsigned int mux = mux_line_to_num(line);
2927 bool alloc = false;
2928 int ret;
2929
2930 line = line & 0x3F;
2931
2932 if (mux >= MAX_MUX)
2933 return -ENXIO;
2934 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
2935 if (gsm_mux[mux] == NULL)
2936 return -EUNATCH;
2937 if (line == 0 || line > 61) /* 62/63 reserved */
2938 return -ECHRNG;
2939 gsm = gsm_mux[mux];
2940 if (gsm->dead)
2941 return -EL2HLT;
2942 /* If DLCI 0 is not yet fully open return an error.
2943 This is ok from a locking
2944 perspective as we don't have to worry about this
2945 if DLCI0 is lost */
2946 mutex_lock(&gsm->mutex);
2947 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN) {
2948 mutex_unlock(&gsm->mutex);
2949 return -EL2NSYNC;
2950 }
2951 dlci = gsm->dlci[line];
2952 if (dlci == NULL) {
2953 alloc = true;
2954 dlci = gsm_dlci_alloc(gsm, line);
2955 }
2956 if (dlci == NULL) {
2957 mutex_unlock(&gsm->mutex);
2958 return -ENOMEM;
2959 }
2960 ret = tty_port_install(&dlci->port, driver, tty);
2961 if (ret) {
2962 if (alloc)
2963 dlci_put(dlci);
2964 mutex_unlock(&gsm->mutex);
2965 return ret;
2966 }
2967
2968 dlci_get(dlci);
2969 dlci_get(gsm->dlci[0]);
2970 mux_get(gsm);
2971 tty->driver_data = dlci;
2972 mutex_unlock(&gsm->mutex);
2973
2974 return 0;
2975}
2976
2977static int gsmtty_open(struct tty_struct *tty, struct file *filp)
2978{
2979 struct gsm_dlci *dlci = tty->driver_data;
2980 struct tty_port *port = &dlci->port;
2981
2982 port->count++;
2983 tty_port_tty_set(port, tty);
2984
2985 dlci->modem_rx = 0;
2986 /* We could in theory open and close before we wait - eg if we get
2987 a DM straight back. This is ok as that will have caused a hangup */
2988 tty_port_set_initialized(port, 1);
2989 /* Start sending off SABM messages */
2990 gsm_dlci_begin_open(dlci);
2991 /* And wait for virtual carrier */
2992 return tty_port_block_til_ready(port, tty, filp);
2993}
2994
2995static void gsmtty_close(struct tty_struct *tty, struct file *filp)
2996{
2997 struct gsm_dlci *dlci = tty->driver_data;
2998
2999 if (dlci == NULL)
3000 return;
3001 if (dlci->state == DLCI_CLOSED)
3002 return;
3003 mutex_lock(&dlci->mutex);
3004 gsm_destroy_network(dlci);
3005 mutex_unlock(&dlci->mutex);
3006 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
3007 return;
3008 gsm_dlci_begin_close(dlci);
3009 if (tty_port_initialized(&dlci->port) && C_HUPCL(tty))
3010 tty_port_lower_dtr_rts(&dlci->port);
3011 tty_port_close_end(&dlci->port, tty);
3012 tty_port_tty_set(&dlci->port, NULL);
3013 return;
3014}
3015
3016static void gsmtty_hangup(struct tty_struct *tty)
3017{
3018 struct gsm_dlci *dlci = tty->driver_data;
3019 if (dlci->state == DLCI_CLOSED)
3020 return;
3021 tty_port_hangup(&dlci->port);
3022 gsm_dlci_begin_close(dlci);
3023}
3024
3025static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf,
3026 int len)
3027{
3028 int sent;
3029 struct gsm_dlci *dlci = tty->driver_data;
3030 if (dlci->state == DLCI_CLOSED)
3031 return -EINVAL;
3032 /* Stuff the bytes into the fifo queue */
3033 sent = kfifo_in_locked(dlci->fifo, buf, len, &dlci->lock);
3034 /* Need to kick the channel */
3035 gsm_dlci_data_kick(dlci);
3036 return sent;
3037}
3038
3039static int gsmtty_write_room(struct tty_struct *tty)
3040{
3041 struct gsm_dlci *dlci = tty->driver_data;
3042 if (dlci->state == DLCI_CLOSED)
3043 return -EINVAL;
3044 return TX_SIZE - kfifo_len(dlci->fifo);
3045}
3046
3047static int gsmtty_chars_in_buffer(struct tty_struct *tty)
3048{
3049 struct gsm_dlci *dlci = tty->driver_data;
3050 if (dlci->state == DLCI_CLOSED)
3051 return -EINVAL;
3052 return kfifo_len(dlci->fifo);
3053}
3054
3055static void gsmtty_flush_buffer(struct tty_struct *tty)
3056{
3057 struct gsm_dlci *dlci = tty->driver_data;
3058 if (dlci->state == DLCI_CLOSED)
3059 return;
3060 /* Caution needed: If we implement reliable transport classes
3061 then the data being transmitted can't simply be junked once
3062 it has first hit the stack. Until then we can just blow it
3063 away */
3064 kfifo_reset(dlci->fifo);
3065 /* Need to unhook this DLCI from the transmit queue logic */
3066}
3067
3068static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
3069{
3070 /* The FIFO handles the queue so the kernel will do the right
3071 thing waiting on chars_in_buffer before calling us. No work
3072 to do here */
3073}
3074
3075static int gsmtty_tiocmget(struct tty_struct *tty)
3076{
3077 struct gsm_dlci *dlci = tty->driver_data;
3078 if (dlci->state == DLCI_CLOSED)
3079 return -EINVAL;
3080 return dlci->modem_rx;
3081}
3082
3083static int gsmtty_tiocmset(struct tty_struct *tty,
3084 unsigned int set, unsigned int clear)
3085{
3086 struct gsm_dlci *dlci = tty->driver_data;
3087 unsigned int modem_tx = dlci->modem_tx;
3088
3089 if (dlci->state == DLCI_CLOSED)
3090 return -EINVAL;
3091 modem_tx &= ~clear;
3092 modem_tx |= set;
3093
3094 if (modem_tx != dlci->modem_tx) {
3095 dlci->modem_tx = modem_tx;
3096 return gsmtty_modem_update(dlci, 0);
3097 }
3098 return 0;
3099}
3100
3101
3102static int gsmtty_ioctl(struct tty_struct *tty,
3103 unsigned int cmd, unsigned long arg)
3104{
3105 struct gsm_dlci *dlci = tty->driver_data;
3106 struct gsm_netconfig nc;
3107 int index;
3108
3109 if (dlci->state == DLCI_CLOSED)
3110 return -EINVAL;
3111 switch (cmd) {
3112 case GSMIOC_ENABLE_NET:
3113 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc)))
3114 return -EFAULT;
3115 nc.if_name[IFNAMSIZ-1] = '\0';
3116 /* return net interface index or error code */
3117 mutex_lock(&dlci->mutex);
3118 index = gsm_create_network(dlci, &nc);
3119 mutex_unlock(&dlci->mutex);
3120 if (copy_to_user((void __user *)arg, &nc, sizeof(nc)))
3121 return -EFAULT;
3122 return index;
3123 case GSMIOC_DISABLE_NET:
3124 if (!capable(CAP_NET_ADMIN))
3125 return -EPERM;
3126 mutex_lock(&dlci->mutex);
3127 gsm_destroy_network(dlci);
3128 mutex_unlock(&dlci->mutex);
3129 return 0;
3130 default:
3131 return -ENOIOCTLCMD;
3132 }
3133}
3134
3135static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old)
3136{
3137 struct gsm_dlci *dlci = tty->driver_data;
3138 if (dlci->state == DLCI_CLOSED)
3139 return;
3140 /* For the moment its fixed. In actual fact the speed information
3141 for the virtual channel can be propogated in both directions by
3142 the RPN control message. This however rapidly gets nasty as we
3143 then have to remap modem signals each way according to whether
3144 our virtual cable is null modem etc .. */
3145 tty_termios_copy_hw(&tty->termios, old);
3146}
3147
3148static void gsmtty_throttle(struct tty_struct *tty)
3149{
3150 struct gsm_dlci *dlci = tty->driver_data;
3151 if (dlci->state == DLCI_CLOSED)
3152 return;
3153 if (C_CRTSCTS(tty))
3154 dlci->modem_tx &= ~TIOCM_DTR;
3155 dlci->throttled = 1;
3156 /* Send an MSC with DTR cleared */
3157 gsmtty_modem_update(dlci, 0);
3158}
3159
3160static void gsmtty_unthrottle(struct tty_struct *tty)
3161{
3162 struct gsm_dlci *dlci = tty->driver_data;
3163 if (dlci->state == DLCI_CLOSED)
3164 return;
3165 if (C_CRTSCTS(tty))
3166 dlci->modem_tx |= TIOCM_DTR;
3167 dlci->throttled = 0;
3168 /* Send an MSC with DTR set */
3169 gsmtty_modem_update(dlci, 0);
3170}
3171
3172static int gsmtty_break_ctl(struct tty_struct *tty, int state)
3173{
3174 struct gsm_dlci *dlci = tty->driver_data;
3175 int encode = 0; /* Off */
3176 if (dlci->state == DLCI_CLOSED)
3177 return -EINVAL;
3178
3179 if (state == -1) /* "On indefinitely" - we can't encode this
3180 properly */
3181 encode = 0x0F;
3182 else if (state > 0) {
3183 encode = state / 200; /* mS to encoding */
3184 if (encode > 0x0F)
3185 encode = 0x0F; /* Best effort */
3186 }
3187 return gsmtty_modem_update(dlci, encode);
3188}
3189
3190static void gsmtty_cleanup(struct tty_struct *tty)
3191{
3192 struct gsm_dlci *dlci = tty->driver_data;
3193 struct gsm_mux *gsm = dlci->gsm;
3194
3195 dlci_put(dlci);
3196 dlci_put(gsm->dlci[0]);
3197 mux_put(gsm);
3198}
3199
3200/* Virtual ttys for the demux */
3201static const struct tty_operations gsmtty_ops = {
3202 .install = gsmtty_install,
3203 .open = gsmtty_open,
3204 .close = gsmtty_close,
3205 .write = gsmtty_write,
3206 .write_room = gsmtty_write_room,
3207 .chars_in_buffer = gsmtty_chars_in_buffer,
3208 .flush_buffer = gsmtty_flush_buffer,
3209 .ioctl = gsmtty_ioctl,
3210 .throttle = gsmtty_throttle,
3211 .unthrottle = gsmtty_unthrottle,
3212 .set_termios = gsmtty_set_termios,
3213 .hangup = gsmtty_hangup,
3214 .wait_until_sent = gsmtty_wait_until_sent,
3215 .tiocmget = gsmtty_tiocmget,
3216 .tiocmset = gsmtty_tiocmset,
3217 .break_ctl = gsmtty_break_ctl,
3218 .cleanup = gsmtty_cleanup,
3219};
3220
3221
3222
3223static int __init gsm_init(void)
3224{
3225 /* Fill in our line protocol discipline, and register it */
3226 int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet);
3227 if (status != 0) {
3228 pr_err("n_gsm: can't register line discipline (err = %d)\n",
3229 status);
3230 return status;
3231 }
3232
3233 gsm_tty_driver = alloc_tty_driver(256);
3234 if (!gsm_tty_driver) {
3235 tty_unregister_ldisc(N_GSM0710);
3236 pr_err("gsm_init: tty allocation failed.\n");
3237 return -EINVAL;
3238 }
3239 gsm_tty_driver->driver_name = "gsmtty";
3240 gsm_tty_driver->name = "gsmtty";
3241 gsm_tty_driver->major = 0; /* Dynamic */
3242 gsm_tty_driver->minor_start = 0;
3243 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
3244 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
3245 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV
3246 | TTY_DRIVER_HARDWARE_BREAK;
3247 gsm_tty_driver->init_termios = tty_std_termios;
3248 /* Fixme */
3249 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
3250 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
3251
3252 spin_lock_init(&gsm_mux_lock);
3253
3254 if (tty_register_driver(gsm_tty_driver)) {
3255 put_tty_driver(gsm_tty_driver);
3256 tty_unregister_ldisc(N_GSM0710);
3257 pr_err("gsm_init: tty registration failed.\n");
3258 return -EBUSY;
3259 }
3260 pr_debug("gsm_init: loaded as %d,%d.\n",
3261 gsm_tty_driver->major, gsm_tty_driver->minor_start);
3262 return 0;
3263}
3264
3265static void __exit gsm_exit(void)
3266{
3267 int status = tty_unregister_ldisc(N_GSM0710);
3268 if (status != 0)
3269 pr_err("n_gsm: can't unregister line discipline (err = %d)\n",
3270 status);
3271 tty_unregister_driver(gsm_tty_driver);
3272 put_tty_driver(gsm_tty_driver);
3273}
3274
3275module_init(gsm_init);
3276module_exit(gsm_exit);
3277
3278
3279MODULE_LICENSE("GPL");
3280MODULE_ALIAS_LDISC(N_GSM0710);