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Alan Coxe1eaea42010-03-26 11:32:54 +00001/*
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
Alan Cox5f9a31d2010-11-04 15:17:27 +000022 * Partly done: hooks so you can pull off frames to non tty devs
Alan Coxe1eaea42010-03-26 11:32:54 +000023 * 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>
Alan Coxe1eaea42010-03-26 11:32:54 +000046#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 <linux/gsmmux.h>
62
63static int debug;
64module_param(debug, int, 0600);
65
66#define T1 (HZ/10)
67#define T2 (HZ/3)
68#define N2 3
69
70/* Use long timers for testing at low speed with debug on */
71#ifdef DEBUG_TIMING
72#define T1 HZ
73#define T2 (2 * HZ)
74#endif
75
Alan Cox5f9a31d2010-11-04 15:17:27 +000076/*
77 * Semi-arbitary buffer size limits. 0710 is normally run with 32-64 byte
78 * limits so this is plenty
79 */
Alan Coxe1eaea42010-03-26 11:32:54 +000080#define MAX_MRU 512
81#define MAX_MTU 512
82
83/*
84 * Each block of data we have queued to go out is in the form of
85 * a gsm_msg which holds everything we need in a link layer independant
86 * format
87 */
88
89struct gsm_msg {
90 struct gsm_msg *next;
91 u8 addr; /* DLCI address + flags */
92 u8 ctrl; /* Control byte + flags */
93 unsigned int len; /* Length of data block (can be zero) */
94 unsigned char *data; /* Points into buffer but not at the start */
95 unsigned char buffer[0];
96};
97
98/*
99 * Each active data link has a gsm_dlci structure associated which ties
100 * the link layer to an optional tty (if the tty side is open). To avoid
101 * complexity right now these are only ever freed up when the mux is
102 * shut down.
103 *
104 * At the moment we don't free DLCI objects until the mux is torn down
105 * this avoid object life time issues but might be worth review later.
106 */
107
108struct gsm_dlci {
109 struct gsm_mux *gsm;
110 int addr;
111 int state;
112#define DLCI_CLOSED 0
113#define DLCI_OPENING 1 /* Sending SABM not seen UA */
114#define DLCI_OPEN 2 /* SABM/UA complete */
115#define DLCI_CLOSING 3 /* Sending DISC not seen UA/DM */
116
117 /* Link layer */
118 spinlock_t lock; /* Protects the internal state */
119 struct timer_list t1; /* Retransmit timer for SABM and UA */
120 int retries;
121 /* Uplink tty if active */
122 struct tty_port port; /* The tty bound to this DLCI if there is one */
123 struct kfifo *fifo; /* Queue fifo for the DLCI */
124 struct kfifo _fifo; /* For new fifo API porting only */
125 int adaption; /* Adaption layer in use */
126 u32 modem_rx; /* Our incoming virtual modem lines */
127 u32 modem_tx; /* Our outgoing modem lines */
128 int dead; /* Refuse re-open */
129 /* Flow control */
130 int throttled; /* Private copy of throttle state */
131 int constipated; /* Throttle status for outgoing */
132 /* Packetised I/O */
133 struct sk_buff *skb; /* Frame being sent */
134 struct sk_buff_head skb_list; /* Queued frames */
135 /* Data handling callback */
136 void (*data)(struct gsm_dlci *dlci, u8 *data, int len);
137};
138
139/* DLCI 0, 62/63 are special or reseved see gsmtty_open */
140
141#define NUM_DLCI 64
142
143/*
144 * DLCI 0 is used to pass control blocks out of band of the data
145 * flow (and with a higher link priority). One command can be outstanding
146 * at a time and we use this structure to manage them. They are created
147 * and destroyed by the user context, and updated by the receive paths
148 * and timers
149 */
150
151struct gsm_control {
152 u8 cmd; /* Command we are issuing */
153 u8 *data; /* Data for the command in case we retransmit */
154 int len; /* Length of block for retransmission */
155 int done; /* Done flag */
156 int error; /* Error if any */
157};
158
159/*
160 * Each GSM mux we have is represented by this structure. If we are
161 * operating as an ldisc then we use this structure as our ldisc
162 * state. We need to sort out lifetimes and locking with respect
163 * to the gsm mux array. For now we don't free DLCI objects that
164 * have been instantiated until the mux itself is terminated.
165 *
166 * To consider further: tty open versus mux shutdown.
167 */
168
169struct gsm_mux {
170 struct tty_struct *tty; /* The tty our ldisc is bound to */
171 spinlock_t lock;
172
173 /* Events on the GSM channel */
174 wait_queue_head_t event;
175
176 /* Bits for GSM mode decoding */
177
178 /* Framing Layer */
179 unsigned char *buf;
180 int state;
181#define GSM_SEARCH 0
182#define GSM_START 1
183#define GSM_ADDRESS 2
184#define GSM_CONTROL 3
185#define GSM_LEN 4
186#define GSM_DATA 5
187#define GSM_FCS 6
188#define GSM_OVERRUN 7
Alan Coxc2f2f002010-11-04 15:17:03 +0000189#define GSM_LEN0 8
190#define GSM_LEN1 9
191#define GSM_SSOF 10
Alan Coxe1eaea42010-03-26 11:32:54 +0000192 unsigned int len;
193 unsigned int address;
194 unsigned int count;
195 int escape;
196 int encoding;
197 u8 control;
198 u8 fcs;
Alan Coxc2f2f002010-11-04 15:17:03 +0000199 u8 received_fcs;
Alan Coxe1eaea42010-03-26 11:32:54 +0000200 u8 *txframe; /* TX framing buffer */
201
202 /* Methods for the receiver side */
203 void (*receive)(struct gsm_mux *gsm, u8 ch);
204 void (*error)(struct gsm_mux *gsm, u8 ch, u8 flag);
205 /* And transmit side */
206 int (*output)(struct gsm_mux *mux, u8 *data, int len);
207
208 /* Link Layer */
209 unsigned int mru;
210 unsigned int mtu;
211 int initiator; /* Did we initiate connection */
212 int dead; /* Has the mux been shut down */
213 struct gsm_dlci *dlci[NUM_DLCI];
214 int constipated; /* Asked by remote to shut up */
215
216 spinlock_t tx_lock;
217 unsigned int tx_bytes; /* TX data outstanding */
218#define TX_THRESH_HI 8192
219#define TX_THRESH_LO 2048
220 struct gsm_msg *tx_head; /* Pending data packets */
221 struct gsm_msg *tx_tail;
222
223 /* Control messages */
224 struct timer_list t2_timer; /* Retransmit timer for commands */
225 int cretries; /* Command retry counter */
226 struct gsm_control *pending_cmd;/* Our current pending command */
227 spinlock_t control_lock; /* Protects the pending command */
228
229 /* Configuration */
230 int adaption; /* 1 or 2 supported */
231 u8 ftype; /* UI or UIH */
232 int t1, t2; /* Timers in 1/100th of a sec */
233 int n2; /* Retry count */
234
235 /* Statistics (not currently exposed) */
236 unsigned long bad_fcs;
237 unsigned long malformed;
238 unsigned long io_error;
239 unsigned long bad_size;
240 unsigned long unsupported;
241};
242
243
244/*
245 * Mux objects - needed so that we can translate a tty index into the
246 * relevant mux and DLCI.
247 */
248
249#define MAX_MUX 4 /* 256 minors */
250static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */
251static spinlock_t gsm_mux_lock;
252
253/*
254 * This section of the driver logic implements the GSM encodings
255 * both the basic and the 'advanced'. Reliable transport is not
256 * supported.
257 */
258
259#define CR 0x02
260#define EA 0x01
261#define PF 0x10
262
263/* I is special: the rest are ..*/
264#define RR 0x01
265#define UI 0x03
266#define RNR 0x05
267#define REJ 0x09
268#define DM 0x0F
269#define SABM 0x2F
270#define DISC 0x43
271#define UA 0x63
272#define UIH 0xEF
273
274/* Channel commands */
275#define CMD_NSC 0x09
276#define CMD_TEST 0x11
277#define CMD_PSC 0x21
278#define CMD_RLS 0x29
279#define CMD_FCOFF 0x31
280#define CMD_PN 0x41
281#define CMD_RPN 0x49
282#define CMD_FCON 0x51
283#define CMD_CLD 0x61
284#define CMD_SNC 0x69
285#define CMD_MSC 0x71
286
287/* Virtual modem bits */
288#define MDM_FC 0x01
289#define MDM_RTC 0x02
290#define MDM_RTR 0x04
291#define MDM_IC 0x20
292#define MDM_DV 0x40
293
294#define GSM0_SOF 0xF9
Alan Cox5f9a31d2010-11-04 15:17:27 +0000295#define GSM1_SOF 0x7E
Alan Coxe1eaea42010-03-26 11:32:54 +0000296#define GSM1_ESCAPE 0x7D
297#define GSM1_ESCAPE_BITS 0x20
298#define XON 0x11
299#define XOFF 0x13
300
301static const struct tty_port_operations gsm_port_ops;
302
303/*
304 * CRC table for GSM 0710
305 */
306
307static const u8 gsm_fcs8[256] = {
308 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75,
309 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B,
310 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69,
311 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67,
312 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D,
313 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43,
314 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51,
315 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F,
316 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05,
317 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B,
318 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19,
319 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17,
320 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D,
321 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33,
322 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21,
323 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F,
324 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95,
325 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B,
326 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89,
327 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87,
328 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD,
329 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3,
330 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1,
331 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF,
332 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5,
333 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB,
334 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9,
335 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7,
336 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD,
337 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3,
338 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1,
339 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF
340};
341
342#define INIT_FCS 0xFF
343#define GOOD_FCS 0xCF
344
345/**
346 * gsm_fcs_add - update FCS
347 * @fcs: Current FCS
348 * @c: Next data
349 *
350 * Update the FCS to include c. Uses the algorithm in the specification
351 * notes.
352 */
353
354static inline u8 gsm_fcs_add(u8 fcs, u8 c)
355{
356 return gsm_fcs8[fcs ^ c];
357}
358
359/**
360 * gsm_fcs_add_block - update FCS for a block
361 * @fcs: Current FCS
362 * @c: buffer of data
363 * @len: length of buffer
364 *
365 * Update the FCS to include c. Uses the algorithm in the specification
366 * notes.
367 */
368
369static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len)
370{
371 while (len--)
372 fcs = gsm_fcs8[fcs ^ *c++];
373 return fcs;
374}
375
376/**
377 * gsm_read_ea - read a byte into an EA
378 * @val: variable holding value
379 * c: byte going into the EA
380 *
381 * Processes one byte of an EA. Updates the passed variable
382 * and returns 1 if the EA is now completely read
383 */
384
385static int gsm_read_ea(unsigned int *val, u8 c)
386{
387 /* Add the next 7 bits into the value */
388 *val <<= 7;
389 *val |= c >> 1;
390 /* Was this the last byte of the EA 1 = yes*/
391 return c & EA;
392}
393
394/**
395 * gsm_encode_modem - encode modem data bits
396 * @dlci: DLCI to encode from
397 *
398 * Returns the correct GSM encoded modem status bits (6 bit field) for
399 * the current status of the DLCI and attached tty object
400 */
401
402static u8 gsm_encode_modem(const struct gsm_dlci *dlci)
403{
404 u8 modembits = 0;
405 /* FC is true flow control not modem bits */
406 if (dlci->throttled)
407 modembits |= MDM_FC;
408 if (dlci->modem_tx & TIOCM_DTR)
409 modembits |= MDM_RTC;
410 if (dlci->modem_tx & TIOCM_RTS)
411 modembits |= MDM_RTR;
412 if (dlci->modem_tx & TIOCM_RI)
413 modembits |= MDM_IC;
414 if (dlci->modem_tx & TIOCM_CD)
415 modembits |= MDM_DV;
416 return modembits;
417}
418
419/**
420 * gsm_print_packet - display a frame for debug
421 * @hdr: header to print before decode
422 * @addr: address EA from the frame
423 * @cr: C/R bit from the frame
424 * @control: control including PF bit
425 * @data: following data bytes
426 * @dlen: length of data
427 *
428 * Displays a packet in human readable format for debugging purposes. The
429 * style is based on amateur radio LAP-B dump display.
430 */
431
432static void gsm_print_packet(const char *hdr, int addr, int cr,
433 u8 control, const u8 *data, int dlen)
434{
435 if (!(debug & 1))
436 return;
437
Alan Cox5f9a31d2010-11-04 15:17:27 +0000438 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]);
Alan Coxe1eaea42010-03-26 11:32:54 +0000439
440 switch (control & ~PF) {
441 case SABM:
Alan Cox5f9a31d2010-11-04 15:17:27 +0000442 pr_cont("SABM");
Alan Coxe1eaea42010-03-26 11:32:54 +0000443 break;
444 case UA:
Alan Cox5f9a31d2010-11-04 15:17:27 +0000445 pr_cont("UA");
Alan Coxe1eaea42010-03-26 11:32:54 +0000446 break;
447 case DISC:
Alan Cox5f9a31d2010-11-04 15:17:27 +0000448 pr_cont("DISC");
Alan Coxe1eaea42010-03-26 11:32:54 +0000449 break;
450 case DM:
Alan Cox5f9a31d2010-11-04 15:17:27 +0000451 pr_cont("DM");
Alan Coxe1eaea42010-03-26 11:32:54 +0000452 break;
453 case UI:
Alan Cox5f9a31d2010-11-04 15:17:27 +0000454 pr_cont("UI");
Alan Coxe1eaea42010-03-26 11:32:54 +0000455 break;
456 case UIH:
Alan Cox5f9a31d2010-11-04 15:17:27 +0000457 pr_cont("UIH");
Alan Coxe1eaea42010-03-26 11:32:54 +0000458 break;
459 default:
460 if (!(control & 0x01)) {
Alan Cox5f9a31d2010-11-04 15:17:27 +0000461 pr_cont("I N(S)%d N(R)%d",
462 (control & 0x0E) >> 1, (control & 0xE) >> 5);
Alan Coxe1eaea42010-03-26 11:32:54 +0000463 } else switch (control & 0x0F) {
Alan Cox5f9a31d2010-11-04 15:17:27 +0000464 case RR:
465 pr_cont("RR(%d)", (control & 0xE0) >> 5);
466 break;
467 case RNR:
468 pr_cont("RNR(%d)", (control & 0xE0) >> 5);
469 break;
470 case REJ:
471 pr_cont("REJ(%d)", (control & 0xE0) >> 5);
472 break;
473 default:
474 pr_cont("[%02X]", control);
Alan Coxe1eaea42010-03-26 11:32:54 +0000475 }
476 }
477
478 if (control & PF)
Alan Cox5f9a31d2010-11-04 15:17:27 +0000479 pr_cont("(P)");
Alan Coxe1eaea42010-03-26 11:32:54 +0000480 else
Alan Cox5f9a31d2010-11-04 15:17:27 +0000481 pr_cont("(F)");
Alan Coxe1eaea42010-03-26 11:32:54 +0000482
483 if (dlen) {
484 int ct = 0;
485 while (dlen--) {
Alan Cox5f9a31d2010-11-04 15:17:27 +0000486 if (ct % 8 == 0) {
487 pr_cont("\n");
488 pr_debug(" ");
489 }
490 pr_cont("%02X ", *data++);
Alan Coxe1eaea42010-03-26 11:32:54 +0000491 ct++;
492 }
493 }
Alan Cox5f9a31d2010-11-04 15:17:27 +0000494 pr_cont("\n");
Alan Coxe1eaea42010-03-26 11:32:54 +0000495}
496
497
498/*
499 * Link level transmission side
500 */
501
502/**
503 * gsm_stuff_packet - bytestuff a packet
504 * @ibuf: input
505 * @obuf: output
506 * @len: length of input
507 *
508 * Expand a buffer by bytestuffing it. The worst case size change
509 * is doubling and the caller is responsible for handing out
510 * suitable sized buffers.
511 */
512
513static int gsm_stuff_frame(const u8 *input, u8 *output, int len)
514{
515 int olen = 0;
516 while (len--) {
517 if (*input == GSM1_SOF || *input == GSM1_ESCAPE
518 || *input == XON || *input == XOFF) {
519 *output++ = GSM1_ESCAPE;
520 *output++ = *input++ ^ GSM1_ESCAPE_BITS;
521 olen++;
522 } else
523 *output++ = *input++;
524 olen++;
525 }
526 return olen;
527}
528
529static void hex_packet(const unsigned char *p, int len)
530{
531 int i;
532 for (i = 0; i < len; i++) {
Alan Cox5f9a31d2010-11-04 15:17:27 +0000533 if (i && (i % 16) == 0) {
534 pr_cont("\n");
535 pr_debug("");
536 }
537 pr_cont("%02X ", *p++);
Alan Coxe1eaea42010-03-26 11:32:54 +0000538 }
Alan Cox5f9a31d2010-11-04 15:17:27 +0000539 pr_cont("\n");
Alan Coxe1eaea42010-03-26 11:32:54 +0000540}
541
542/**
543 * gsm_send - send a control frame
544 * @gsm: our GSM mux
545 * @addr: address for control frame
546 * @cr: command/response bit
547 * @control: control byte including PF bit
548 *
549 * Format up and transmit a control frame. These do not go via the
550 * queueing logic as they should be transmitted ahead of data when
551 * they are needed.
552 *
553 * FIXME: Lock versus data TX path
554 */
555
556static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control)
557{
558 int len;
559 u8 cbuf[10];
560 u8 ibuf[3];
561
562 switch (gsm->encoding) {
563 case 0:
564 cbuf[0] = GSM0_SOF;
565 cbuf[1] = (addr << 2) | (cr << 1) | EA;
566 cbuf[2] = control;
567 cbuf[3] = EA; /* Length of data = 0 */
568 cbuf[4] = 0xFF - gsm_fcs_add_block(INIT_FCS, cbuf + 1, 3);
569 cbuf[5] = GSM0_SOF;
570 len = 6;
571 break;
572 case 1:
573 case 2:
574 /* Control frame + packing (but not frame stuffing) in mode 1 */
575 ibuf[0] = (addr << 2) | (cr << 1) | EA;
576 ibuf[1] = control;
577 ibuf[2] = 0xFF - gsm_fcs_add_block(INIT_FCS, ibuf, 2);
578 /* Stuffing may double the size worst case */
579 len = gsm_stuff_frame(ibuf, cbuf + 1, 3);
580 /* Now add the SOF markers */
581 cbuf[0] = GSM1_SOF;
582 cbuf[len + 1] = GSM1_SOF;
583 /* FIXME: we can omit the lead one in many cases */
584 len += 2;
585 break;
586 default:
587 WARN_ON(1);
588 return;
589 }
590 gsm->output(gsm, cbuf, len);
591 gsm_print_packet("-->", addr, cr, control, NULL, 0);
592}
593
594/**
595 * gsm_response - send a control response
596 * @gsm: our GSM mux
597 * @addr: address for control frame
598 * @control: control byte including PF bit
599 *
600 * Format up and transmit a link level response frame.
601 */
602
603static inline void gsm_response(struct gsm_mux *gsm, int addr, int control)
604{
605 gsm_send(gsm, addr, 0, control);
606}
607
608/**
609 * gsm_command - send a control command
610 * @gsm: our GSM mux
611 * @addr: address for control frame
612 * @control: control byte including PF bit
613 *
614 * Format up and transmit a link level command frame.
615 */
616
617static inline void gsm_command(struct gsm_mux *gsm, int addr, int control)
618{
619 gsm_send(gsm, addr, 1, control);
620}
621
622/* Data transmission */
623
624#define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */
625
626/**
627 * gsm_data_alloc - allocate data frame
628 * @gsm: GSM mux
629 * @addr: DLCI address
630 * @len: length excluding header and FCS
631 * @ctrl: control byte
632 *
633 * Allocate a new data buffer for sending frames with data. Space is left
634 * at the front for header bytes but that is treated as an implementation
635 * detail and not for the high level code to use
636 */
637
638static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
639 u8 ctrl)
640{
641 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN,
642 GFP_ATOMIC);
643 if (m == NULL)
644 return NULL;
645 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */
646 m->len = len;
647 m->addr = addr;
648 m->ctrl = ctrl;
649 m->next = NULL;
650 return m;
651}
652
653/**
654 * gsm_data_kick - poke the queue
655 * @gsm: GSM Mux
656 *
657 * The tty device has called us to indicate that room has appeared in
658 * the transmit queue. Ram more data into the pipe if we have any
659 *
660 * FIXME: lock against link layer control transmissions
661 */
662
663static void gsm_data_kick(struct gsm_mux *gsm)
664{
665 struct gsm_msg *msg = gsm->tx_head;
666 int len;
667 int skip_sof = 0;
668
669 /* FIXME: We need to apply this solely to data messages */
670 if (gsm->constipated)
671 return;
672
673 while (gsm->tx_head != NULL) {
674 msg = gsm->tx_head;
675 if (gsm->encoding != 0) {
676 gsm->txframe[0] = GSM1_SOF;
677 len = gsm_stuff_frame(msg->data,
678 gsm->txframe + 1, msg->len);
679 gsm->txframe[len + 1] = GSM1_SOF;
680 len += 2;
681 } else {
682 gsm->txframe[0] = GSM0_SOF;
683 memcpy(gsm->txframe + 1 , msg->data, msg->len);
684 gsm->txframe[msg->len + 1] = GSM0_SOF;
685 len = msg->len + 2;
686 }
687
688 if (debug & 4) {
Alan Cox5f9a31d2010-11-04 15:17:27 +0000689 pr_debug("gsm_data_kick:\n");
Alan Coxe1eaea42010-03-26 11:32:54 +0000690 hex_packet(gsm->txframe, len);
691 }
692
693 if (gsm->output(gsm, gsm->txframe + skip_sof,
694 len - skip_sof) < 0)
695 break;
696 /* FIXME: Can eliminate one SOF in many more cases */
697 gsm->tx_head = msg->next;
698 if (gsm->tx_head == NULL)
699 gsm->tx_tail = NULL;
700 gsm->tx_bytes -= msg->len;
701 kfree(msg);
702 /* For a burst of frames skip the extra SOF within the
703 burst */
704 skip_sof = 1;
705 }
706}
707
708/**
709 * __gsm_data_queue - queue a UI or UIH frame
710 * @dlci: DLCI sending the data
711 * @msg: message queued
712 *
713 * Add data to the transmit queue and try and get stuff moving
714 * out of the mux tty if not already doing so. The Caller must hold
715 * the gsm tx lock.
716 */
717
718static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
719{
720 struct gsm_mux *gsm = dlci->gsm;
721 u8 *dp = msg->data;
722 u8 *fcs = dp + msg->len;
723
724 /* Fill in the header */
725 if (gsm->encoding == 0) {
726 if (msg->len < 128)
727 *--dp = (msg->len << 1) | EA;
728 else {
Ken Millsbe7a7412010-12-13 15:27:27 +0000729 *--dp = (msg->len >> 7); /* bits 7 - 15 */
730 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */
Alan Coxe1eaea42010-03-26 11:32:54 +0000731 }
732 }
733
734 *--dp = msg->ctrl;
735 if (gsm->initiator)
736 *--dp = (msg->addr << 2) | 2 | EA;
737 else
738 *--dp = (msg->addr << 2) | EA;
739 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp);
740 /* Ugly protocol layering violation */
741 if (msg->ctrl == UI || msg->ctrl == (UI|PF))
742 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len);
743 *fcs = 0xFF - *fcs;
744
745 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl,
746 msg->data, msg->len);
747
748 /* Move the header back and adjust the length, also allow for the FCS
749 now tacked on the end */
750 msg->len += (msg->data - dp) + 1;
751 msg->data = dp;
752
753 /* Add to the actual output queue */
754 if (gsm->tx_tail)
755 gsm->tx_tail->next = msg;
756 else
757 gsm->tx_head = msg;
758 gsm->tx_tail = msg;
759 gsm->tx_bytes += msg->len;
760 gsm_data_kick(gsm);
761}
762
763/**
764 * gsm_data_queue - queue a UI or UIH frame
765 * @dlci: DLCI sending the data
766 * @msg: message queued
767 *
768 * Add data to the transmit queue and try and get stuff moving
769 * out of the mux tty if not already doing so. Take the
770 * the gsm tx lock and dlci lock.
771 */
772
773static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
774{
775 unsigned long flags;
776 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
777 __gsm_data_queue(dlci, msg);
778 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
779}
780
781/**
782 * gsm_dlci_data_output - try and push data out of a DLCI
783 * @gsm: mux
784 * @dlci: the DLCI to pull data from
785 *
786 * Pull data from a DLCI and send it into the transmit queue if there
787 * is data. Keep to the MRU of the mux. This path handles the usual tty
788 * interface which is a byte stream with optional modem data.
789 *
790 * Caller must hold the tx_lock of the mux.
791 */
792
793static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci)
794{
795 struct gsm_msg *msg;
796 u8 *dp;
797 int len, size;
798 int h = dlci->adaption - 1;
799
800 len = kfifo_len(dlci->fifo);
801 if (len == 0)
802 return 0;
803
804 /* MTU/MRU count only the data bits */
805 if (len > gsm->mtu)
806 len = gsm->mtu;
807
808 size = len + h;
809
810 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
811 /* FIXME: need a timer or something to kick this so it can't
812 get stuck with no work outstanding and no buffer free */
813 if (msg == NULL)
814 return -ENOMEM;
815 dp = msg->data;
816 switch (dlci->adaption) {
817 case 1: /* Unstructured */
818 break;
819 case 2: /* Unstructed with modem bits. Always one byte as we never
820 send inline break data */
821 *dp += gsm_encode_modem(dlci);
822 len--;
823 break;
824 }
825 WARN_ON(kfifo_out_locked(dlci->fifo, dp , len, &dlci->lock) != len);
826 __gsm_data_queue(dlci, msg);
827 /* Bytes of data we used up */
828 return 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(&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 kfree_skb(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 return -ENOMEM;
884 dp = msg->data;
885
886 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */
887 /* Flag byte to carry the start/end info */
888 *dp++ = last << 7 | first << 6 | 1; /* EA */
889 len--;
890 }
891 memcpy(dp, skb_pull(dlci->skb, len), len);
892 __gsm_data_queue(dlci, msg);
893 if (last)
894 dlci->skb = NULL;
895 return size;
896}
897
898/**
899 * gsm_dlci_data_sweep - look for data to send
900 * @gsm: the GSM mux
901 *
902 * Sweep the GSM mux channels in priority order looking for ones with
903 * data to send. We could do with optimising this scan a bit. We aim
904 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit
905 * TX_THRESH_LO we get called again
906 *
907 * FIXME: We should round robin between groups and in theory you can
908 * renegotiate DLCI priorities with optional stuff. Needs optimising.
909 */
910
911static void gsm_dlci_data_sweep(struct gsm_mux *gsm)
912{
913 int len;
914 /* Priority ordering: We should do priority with RR of the groups */
915 int i = 1;
Alan Coxe1eaea42010-03-26 11:32:54 +0000916
Alan Coxe1eaea42010-03-26 11:32:54 +0000917 while (i < NUM_DLCI) {
918 struct gsm_dlci *dlci;
919
920 if (gsm->tx_bytes > TX_THRESH_HI)
921 break;
922 dlci = gsm->dlci[i];
923 if (dlci == NULL || dlci->constipated) {
924 i++;
925 continue;
926 }
927 if (dlci->adaption < 3)
928 len = gsm_dlci_data_output(gsm, dlci);
929 else
930 len = gsm_dlci_data_output_framed(gsm, dlci);
931 if (len < 0)
Julia Lawalle73790a2010-08-10 18:03:12 -0700932 break;
Alan Coxe1eaea42010-03-26 11:32:54 +0000933 /* DLCI empty - try the next */
934 if (len == 0)
935 i++;
936 }
Alan Coxe1eaea42010-03-26 11:32:54 +0000937}
938
939/**
940 * gsm_dlci_data_kick - transmit if possible
941 * @dlci: DLCI to kick
942 *
943 * Transmit data from this DLCI if the queue is empty. We can't rely on
944 * a tty wakeup except when we filled the pipe so we need to fire off
945 * new data ourselves in other cases.
946 */
947
948static void gsm_dlci_data_kick(struct gsm_dlci *dlci)
949{
950 unsigned long flags;
951
952 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
953 /* If we have nothing running then we need to fire up */
954 if (dlci->gsm->tx_bytes == 0)
955 gsm_dlci_data_output(dlci->gsm, dlci);
956 else if (dlci->gsm->tx_bytes < TX_THRESH_LO)
957 gsm_dlci_data_sweep(dlci->gsm);
958 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
959}
960
961/*
962 * Control message processing
963 */
964
965
966/**
967 * gsm_control_reply - send a response frame to a control
968 * @gsm: gsm channel
969 * @cmd: the command to use
970 * @data: data to follow encoded info
971 * @dlen: length of data
972 *
973 * Encode up and queue a UI/UIH frame containing our response.
974 */
975
976static void gsm_control_reply(struct gsm_mux *gsm, int cmd, u8 *data,
977 int dlen)
978{
979 struct gsm_msg *msg;
980 msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype);
Ken Mills093d8042010-12-13 15:28:03 +0000981 if (msg == NULL)
982 return;
Alan Coxe1eaea42010-03-26 11:32:54 +0000983 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */
984 msg->data[1] = (dlen << 1) | EA;
985 memcpy(msg->data + 2, data, dlen);
986 gsm_data_queue(gsm->dlci[0], msg);
987}
988
989/**
990 * gsm_process_modem - process received modem status
991 * @tty: virtual tty bound to the DLCI
992 * @dlci: DLCI to affect
993 * @modem: modem bits (full EA)
994 *
995 * Used when a modem control message or line state inline in adaption
996 * layer 2 is processed. Sort out the local modem state and throttles
997 */
998
999static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
1000 u32 modem)
1001{
1002 int mlines = 0;
1003 u8 brk = modem >> 6;
1004
1005 /* Flow control/ready to communicate */
1006 if (modem & MDM_FC) {
1007 /* Need to throttle our output on this device */
1008 dlci->constipated = 1;
1009 }
1010 if (modem & MDM_RTC) {
1011 mlines |= TIOCM_DSR | TIOCM_DTR;
1012 dlci->constipated = 0;
1013 gsm_dlci_data_kick(dlci);
1014 }
1015 /* Map modem bits */
1016 if (modem & MDM_RTR)
1017 mlines |= TIOCM_RTS | TIOCM_CTS;
1018 if (modem & MDM_IC)
1019 mlines |= TIOCM_RI;
1020 if (modem & MDM_DV)
1021 mlines |= TIOCM_CD;
1022
1023 /* Carrier drop -> hangup */
1024 if (tty) {
1025 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD))
1026 if (!(tty->termios->c_cflag & CLOCAL))
1027 tty_hangup(tty);
1028 if (brk & 0x01)
1029 tty_insert_flip_char(tty, 0, TTY_BREAK);
1030 }
1031 dlci->modem_rx = mlines;
1032}
1033
1034/**
1035 * gsm_control_modem - modem status received
1036 * @gsm: GSM channel
1037 * @data: data following command
1038 * @clen: command length
1039 *
1040 * We have received a modem status control message. This is used by
1041 * the GSM mux protocol to pass virtual modem line status and optionally
1042 * to indicate break signals. Unpack it, convert to Linux representation
1043 * and if need be stuff a break message down the tty.
1044 */
1045
1046static void gsm_control_modem(struct gsm_mux *gsm, u8 *data, int clen)
1047{
1048 unsigned int addr = 0;
1049 unsigned int modem = 0;
1050 struct gsm_dlci *dlci;
1051 int len = clen;
1052 u8 *dp = data;
1053 struct tty_struct *tty;
1054
1055 while (gsm_read_ea(&addr, *dp++) == 0) {
1056 len--;
1057 if (len == 0)
1058 return;
1059 }
1060 /* Must be at least one byte following the EA */
1061 len--;
1062 if (len <= 0)
1063 return;
1064
1065 addr >>= 1;
1066 /* Closed port, or invalid ? */
1067 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1068 return;
1069 dlci = gsm->dlci[addr];
1070
1071 while (gsm_read_ea(&modem, *dp++) == 0) {
1072 len--;
1073 if (len == 0)
1074 return;
1075 }
1076 tty = tty_port_tty_get(&dlci->port);
1077 gsm_process_modem(tty, dlci, modem);
1078 if (tty) {
1079 tty_wakeup(tty);
1080 tty_kref_put(tty);
1081 }
1082 gsm_control_reply(gsm, CMD_MSC, data, clen);
1083}
1084
1085/**
1086 * gsm_control_rls - remote line status
1087 * @gsm: GSM channel
1088 * @data: data bytes
1089 * @clen: data length
1090 *
1091 * The modem sends us a two byte message on the control channel whenever
1092 * it wishes to send us an error state from the virtual link. Stuff
1093 * this into the uplink tty if present
1094 */
1095
1096static void gsm_control_rls(struct gsm_mux *gsm, u8 *data, int clen)
1097{
1098 struct tty_struct *tty;
1099 unsigned int addr = 0 ;
1100 u8 bits;
1101 int len = clen;
1102 u8 *dp = data;
1103
1104 while (gsm_read_ea(&addr, *dp++) == 0) {
1105 len--;
1106 if (len == 0)
1107 return;
1108 }
1109 /* Must be at least one byte following ea */
1110 len--;
1111 if (len <= 0)
1112 return;
1113 addr >>= 1;
1114 /* Closed port, or invalid ? */
1115 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1116 return;
1117 /* No error ? */
1118 bits = *dp;
1119 if ((bits & 1) == 0)
1120 return;
1121 /* See if we have an uplink tty */
1122 tty = tty_port_tty_get(&gsm->dlci[addr]->port);
1123
1124 if (tty) {
1125 if (bits & 2)
1126 tty_insert_flip_char(tty, 0, TTY_OVERRUN);
1127 if (bits & 4)
1128 tty_insert_flip_char(tty, 0, TTY_PARITY);
1129 if (bits & 8)
1130 tty_insert_flip_char(tty, 0, TTY_FRAME);
1131 tty_flip_buffer_push(tty);
1132 tty_kref_put(tty);
1133 }
1134 gsm_control_reply(gsm, CMD_RLS, data, clen);
1135}
1136
1137static void gsm_dlci_begin_close(struct gsm_dlci *dlci);
1138
1139/**
1140 * gsm_control_message - DLCI 0 control processing
1141 * @gsm: our GSM mux
1142 * @command: the command EA
1143 * @data: data beyond the command/length EAs
1144 * @clen: length
1145 *
1146 * Input processor for control messages from the other end of the link.
1147 * Processes the incoming request and queues a response frame or an
1148 * NSC response if not supported
1149 */
1150
1151static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
1152 u8 *data, int clen)
1153{
1154 u8 buf[1];
1155 switch (command) {
1156 case CMD_CLD: {
1157 struct gsm_dlci *dlci = gsm->dlci[0];
1158 /* Modem wishes to close down */
1159 if (dlci) {
1160 dlci->dead = 1;
1161 gsm->dead = 1;
1162 gsm_dlci_begin_close(dlci);
1163 }
1164 }
1165 break;
1166 case CMD_TEST:
1167 /* Modem wishes to test, reply with the data */
1168 gsm_control_reply(gsm, CMD_TEST, data, clen);
1169 break;
1170 case CMD_FCON:
1171 /* Modem wants us to STFU */
1172 gsm->constipated = 1;
1173 gsm_control_reply(gsm, CMD_FCON, NULL, 0);
1174 break;
1175 case CMD_FCOFF:
1176 /* Modem can accept data again */
1177 gsm->constipated = 0;
1178 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0);
1179 /* Kick the link in case it is idling */
1180 gsm_data_kick(gsm);
1181 break;
1182 case CMD_MSC:
1183 /* Out of band modem line change indicator for a DLCI */
1184 gsm_control_modem(gsm, data, clen);
1185 break;
1186 case CMD_RLS:
1187 /* Out of band error reception for a DLCI */
1188 gsm_control_rls(gsm, data, clen);
1189 break;
1190 case CMD_PSC:
1191 /* Modem wishes to enter power saving state */
1192 gsm_control_reply(gsm, CMD_PSC, NULL, 0);
1193 break;
1194 /* Optional unsupported commands */
1195 case CMD_PN: /* Parameter negotiation */
1196 case CMD_RPN: /* Remote port negotation */
1197 case CMD_SNC: /* Service negotation command */
1198 default:
1199 /* Reply to bad commands with an NSC */
1200 buf[0] = command;
1201 gsm_control_reply(gsm, CMD_NSC, buf, 1);
1202 break;
1203 }
1204}
1205
1206/**
1207 * gsm_control_response - process a response to our control
1208 * @gsm: our GSM mux
1209 * @command: the command (response) EA
1210 * @data: data beyond the command/length EA
1211 * @clen: length
1212 *
1213 * Process a response to an outstanding command. We only allow a single
1214 * control message in flight so this is fairly easy. All the clean up
1215 * is done by the caller, we just update the fields, flag it as done
1216 * and return
1217 */
1218
1219static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
1220 u8 *data, int clen)
1221{
1222 struct gsm_control *ctrl;
1223 unsigned long flags;
1224
1225 spin_lock_irqsave(&gsm->control_lock, flags);
1226
1227 ctrl = gsm->pending_cmd;
1228 /* Does the reply match our command */
1229 command |= 1;
1230 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) {
1231 /* Our command was replied to, kill the retry timer */
1232 del_timer(&gsm->t2_timer);
1233 gsm->pending_cmd = NULL;
1234 /* Rejected by the other end */
1235 if (command == CMD_NSC)
1236 ctrl->error = -EOPNOTSUPP;
1237 ctrl->done = 1;
1238 wake_up(&gsm->event);
1239 }
1240 spin_unlock_irqrestore(&gsm->control_lock, flags);
1241}
1242
1243/**
Alan Cox5f9a31d2010-11-04 15:17:27 +00001244 * gsm_control_transmit - send control packet
Alan Coxe1eaea42010-03-26 11:32:54 +00001245 * @gsm: gsm mux
1246 * @ctrl: frame to send
1247 *
1248 * Send out a pending control command (called under control lock)
1249 */
1250
1251static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl)
1252{
1253 struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1,
1254 gsm->ftype|PF);
1255 if (msg == NULL)
1256 return;
1257 msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */
1258 memcpy(msg->data + 1, ctrl->data, ctrl->len);
1259 gsm_data_queue(gsm->dlci[0], msg);
1260}
1261
1262/**
1263 * gsm_control_retransmit - retransmit a control frame
1264 * @data: pointer to our gsm object
1265 *
1266 * Called off the T2 timer expiry in order to retransmit control frames
1267 * that have been lost in the system somewhere. The control_lock protects
1268 * us from colliding with another sender or a receive completion event.
1269 * In that situation the timer may still occur in a small window but
1270 * gsm->pending_cmd will be NULL and we just let the timer expire.
1271 */
1272
1273static void gsm_control_retransmit(unsigned long data)
1274{
1275 struct gsm_mux *gsm = (struct gsm_mux *)data;
1276 struct gsm_control *ctrl;
1277 unsigned long flags;
1278 spin_lock_irqsave(&gsm->control_lock, flags);
1279 ctrl = gsm->pending_cmd;
1280 if (ctrl) {
1281 gsm->cretries--;
1282 if (gsm->cretries == 0) {
1283 gsm->pending_cmd = NULL;
1284 ctrl->error = -ETIMEDOUT;
1285 ctrl->done = 1;
1286 spin_unlock_irqrestore(&gsm->control_lock, flags);
1287 wake_up(&gsm->event);
1288 return;
1289 }
1290 gsm_control_transmit(gsm, ctrl);
1291 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1292 }
1293 spin_unlock_irqrestore(&gsm->control_lock, flags);
1294}
1295
1296/**
1297 * gsm_control_send - send a control frame on DLCI 0
1298 * @gsm: the GSM channel
1299 * @command: command to send including CR bit
1300 * @data: bytes of data (must be kmalloced)
1301 * @len: length of the block to send
1302 *
1303 * Queue and dispatch a control command. Only one command can be
1304 * active at a time. In theory more can be outstanding but the matching
1305 * gets really complicated so for now stick to one outstanding.
1306 */
1307
1308static struct gsm_control *gsm_control_send(struct gsm_mux *gsm,
1309 unsigned int command, u8 *data, int clen)
1310{
1311 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control),
1312 GFP_KERNEL);
1313 unsigned long flags;
1314 if (ctrl == NULL)
1315 return NULL;
1316retry:
1317 wait_event(gsm->event, gsm->pending_cmd == NULL);
1318 spin_lock_irqsave(&gsm->control_lock, flags);
1319 if (gsm->pending_cmd != NULL) {
1320 spin_unlock_irqrestore(&gsm->control_lock, flags);
1321 goto retry;
1322 }
1323 ctrl->cmd = command;
1324 ctrl->data = data;
1325 ctrl->len = clen;
1326 gsm->pending_cmd = ctrl;
1327 gsm->cretries = gsm->n2;
1328 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1329 gsm_control_transmit(gsm, ctrl);
1330 spin_unlock_irqrestore(&gsm->control_lock, flags);
1331 return ctrl;
1332}
1333
1334/**
1335 * gsm_control_wait - wait for a control to finish
1336 * @gsm: GSM mux
1337 * @control: control we are waiting on
1338 *
1339 * Waits for the control to complete or time out. Frees any used
1340 * resources and returns 0 for success, or an error if the remote
1341 * rejected or ignored the request.
1342 */
1343
1344static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
1345{
1346 int err;
1347 wait_event(gsm->event, control->done == 1);
1348 err = control->error;
1349 kfree(control);
1350 return err;
1351}
1352
1353
1354/*
1355 * DLCI level handling: Needs krefs
1356 */
1357
1358/*
1359 * State transitions and timers
1360 */
1361
1362/**
1363 * gsm_dlci_close - a DLCI has closed
1364 * @dlci: DLCI that closed
1365 *
1366 * Perform processing when moving a DLCI into closed state. If there
1367 * is an attached tty this is hung up
1368 */
1369
1370static void gsm_dlci_close(struct gsm_dlci *dlci)
1371{
1372 del_timer(&dlci->t1);
1373 if (debug & 8)
Alan Cox5f9a31d2010-11-04 15:17:27 +00001374 pr_debug("DLCI %d goes closed.\n", dlci->addr);
Alan Coxe1eaea42010-03-26 11:32:54 +00001375 dlci->state = DLCI_CLOSED;
1376 if (dlci->addr != 0) {
1377 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1378 if (tty) {
1379 tty_hangup(tty);
1380 tty_kref_put(tty);
1381 }
1382 kfifo_reset(dlci->fifo);
1383 } else
1384 dlci->gsm->dead = 1;
1385 wake_up(&dlci->gsm->event);
1386 /* A DLCI 0 close is a MUX termination so we need to kick that
1387 back to userspace somehow */
1388}
1389
1390/**
1391 * gsm_dlci_open - a DLCI has opened
1392 * @dlci: DLCI that opened
1393 *
1394 * Perform processing when moving a DLCI into open state.
1395 */
1396
1397static void gsm_dlci_open(struct gsm_dlci *dlci)
1398{
1399 /* Note that SABM UA .. SABM UA first UA lost can mean that we go
1400 open -> open */
1401 del_timer(&dlci->t1);
1402 /* This will let a tty open continue */
1403 dlci->state = DLCI_OPEN;
1404 if (debug & 8)
Alan Cox5f9a31d2010-11-04 15:17:27 +00001405 pr_debug("DLCI %d goes open.\n", dlci->addr);
Alan Coxe1eaea42010-03-26 11:32:54 +00001406 wake_up(&dlci->gsm->event);
1407}
1408
1409/**
1410 * gsm_dlci_t1 - T1 timer expiry
1411 * @dlci: DLCI that opened
1412 *
1413 * The T1 timer handles retransmits of control frames (essentially of
1414 * SABM and DISC). We resend the command until the retry count runs out
1415 * in which case an opening port goes back to closed and a closing port
1416 * is simply put into closed state (any further frames from the other
1417 * end will get a DM response)
1418 */
1419
1420static void gsm_dlci_t1(unsigned long data)
1421{
1422 struct gsm_dlci *dlci = (struct gsm_dlci *)data;
1423 struct gsm_mux *gsm = dlci->gsm;
1424
1425 switch (dlci->state) {
1426 case DLCI_OPENING:
1427 dlci->retries--;
1428 if (dlci->retries) {
1429 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1430 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1431 } else
1432 gsm_dlci_close(dlci);
1433 break;
1434 case DLCI_CLOSING:
1435 dlci->retries--;
1436 if (dlci->retries) {
1437 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1438 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1439 } else
1440 gsm_dlci_close(dlci);
1441 break;
1442 }
1443}
1444
1445/**
1446 * gsm_dlci_begin_open - start channel open procedure
1447 * @dlci: DLCI to open
1448 *
1449 * Commence opening a DLCI from the Linux side. We issue SABM messages
1450 * to the modem which should then reply with a UA, at which point we
1451 * will move into open state. Opening is done asynchronously with retry
1452 * running off timers and the responses.
1453 */
1454
1455static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
1456{
1457 struct gsm_mux *gsm = dlci->gsm;
1458 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING)
1459 return;
1460 dlci->retries = gsm->n2;
1461 dlci->state = DLCI_OPENING;
1462 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1463 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1464}
1465
1466/**
1467 * gsm_dlci_begin_close - start channel open procedure
1468 * @dlci: DLCI to open
1469 *
1470 * Commence closing a DLCI from the Linux side. We issue DISC messages
1471 * to the modem which should then reply with a UA, at which point we
1472 * will move into closed state. Closing is done asynchronously with retry
1473 * off timers. We may also receive a DM reply from the other end which
1474 * indicates the channel was already closed.
1475 */
1476
1477static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
1478{
1479 struct gsm_mux *gsm = dlci->gsm;
1480 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
1481 return;
1482 dlci->retries = gsm->n2;
1483 dlci->state = DLCI_CLOSING;
1484 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1485 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1486}
1487
1488/**
1489 * gsm_dlci_data - data arrived
1490 * @dlci: channel
1491 * @data: block of bytes received
1492 * @len: length of received block
1493 *
1494 * A UI or UIH frame has arrived which contains data for a channel
1495 * other than the control channel. If the relevant virtual tty is
1496 * open we shovel the bits down it, if not we drop them.
1497 */
1498
1499static void gsm_dlci_data(struct gsm_dlci *dlci, u8 *data, int len)
1500{
1501 /* krefs .. */
1502 struct tty_port *port = &dlci->port;
1503 struct tty_struct *tty = tty_port_tty_get(port);
1504 unsigned int modem = 0;
1505
1506 if (debug & 16)
Alan Cox5f9a31d2010-11-04 15:17:27 +00001507 pr_debug("%d bytes for tty %p\n", len, tty);
Alan Coxe1eaea42010-03-26 11:32:54 +00001508 if (tty) {
1509 switch (dlci->adaption) {
Alan Cox5f9a31d2010-11-04 15:17:27 +00001510 /* Unsupported types */
1511 /* Packetised interruptible data */
1512 case 4:
1513 break;
1514 /* Packetised uininterruptible voice/data */
1515 case 3:
1516 break;
1517 /* Asynchronous serial with line state in each frame */
1518 case 2:
1519 while (gsm_read_ea(&modem, *data++) == 0) {
1520 len--;
1521 if (len == 0)
1522 return;
1523 }
1524 gsm_process_modem(tty, dlci, modem);
1525 /* Line state will go via DLCI 0 controls only */
1526 case 1:
1527 default:
1528 tty_insert_flip_string(tty, data, len);
1529 tty_flip_buffer_push(tty);
Alan Coxe1eaea42010-03-26 11:32:54 +00001530 }
1531 tty_kref_put(tty);
1532 }
1533}
1534
1535/**
1536 * gsm_dlci_control - data arrived on control channel
1537 * @dlci: channel
1538 * @data: block of bytes received
1539 * @len: length of received block
1540 *
1541 * A UI or UIH frame has arrived which contains data for DLCI 0 the
1542 * control channel. This should contain a command EA followed by
1543 * control data bytes. The command EA contains a command/response bit
1544 * and we divide up the work accordingly.
1545 */
1546
1547static void gsm_dlci_command(struct gsm_dlci *dlci, u8 *data, int len)
1548{
1549 /* See what command is involved */
1550 unsigned int command = 0;
1551 while (len-- > 0) {
1552 if (gsm_read_ea(&command, *data++) == 1) {
1553 int clen = *data++;
1554 len--;
1555 /* FIXME: this is properly an EA */
1556 clen >>= 1;
1557 /* Malformed command ? */
1558 if (clen > len)
1559 return;
1560 if (command & 1)
1561 gsm_control_message(dlci->gsm, command,
1562 data, clen);
1563 else
1564 gsm_control_response(dlci->gsm, command,
1565 data, clen);
1566 return;
1567 }
1568 }
1569}
1570
1571/*
1572 * Allocate/Free DLCI channels
1573 */
1574
1575/**
1576 * gsm_dlci_alloc - allocate a DLCI
1577 * @gsm: GSM mux
1578 * @addr: address of the DLCI
1579 *
1580 * Allocate and install a new DLCI object into the GSM mux.
1581 *
1582 * FIXME: review locking races
1583 */
1584
1585static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
1586{
1587 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC);
1588 if (dlci == NULL)
1589 return NULL;
1590 spin_lock_init(&dlci->lock);
1591 dlci->fifo = &dlci->_fifo;
1592 if (kfifo_alloc(&dlci->_fifo, 4096, GFP_KERNEL) < 0) {
1593 kfree(dlci);
1594 return NULL;
1595 }
1596
1597 skb_queue_head_init(&dlci->skb_list);
1598 init_timer(&dlci->t1);
1599 dlci->t1.function = gsm_dlci_t1;
1600 dlci->t1.data = (unsigned long)dlci;
1601 tty_port_init(&dlci->port);
1602 dlci->port.ops = &gsm_port_ops;
1603 dlci->gsm = gsm;
1604 dlci->addr = addr;
1605 dlci->adaption = gsm->adaption;
1606 dlci->state = DLCI_CLOSED;
1607 if (addr)
1608 dlci->data = gsm_dlci_data;
1609 else
1610 dlci->data = gsm_dlci_command;
1611 gsm->dlci[addr] = dlci;
1612 return dlci;
1613}
1614
1615/**
1616 * gsm_dlci_free - release DLCI
1617 * @dlci: DLCI to destroy
1618 *
1619 * Free up a DLCI. Currently to keep the lifetime rules sane we only
1620 * clean up DLCI objects when the MUX closes rather than as the port
1621 * is closed down on both the tty and mux levels.
1622 *
1623 * Can sleep.
1624 */
1625static void gsm_dlci_free(struct gsm_dlci *dlci)
1626{
1627 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1628 if (tty) {
1629 tty_vhangup(tty);
1630 tty_kref_put(tty);
1631 }
1632 del_timer_sync(&dlci->t1);
1633 dlci->gsm->dlci[dlci->addr] = NULL;
1634 kfifo_free(dlci->fifo);
1635 kfree(dlci);
1636}
1637
Alan Coxe1eaea42010-03-26 11:32:54 +00001638/*
1639 * LAPBish link layer logic
1640 */
1641
1642/**
1643 * gsm_queue - a GSM frame is ready to process
1644 * @gsm: pointer to our gsm mux
1645 *
1646 * At this point in time a frame has arrived and been demangled from
1647 * the line encoding. All the differences between the encodings have
1648 * been handled below us and the frame is unpacked into the structures.
1649 * The fcs holds the header FCS but any data FCS must be added here.
1650 */
1651
1652static void gsm_queue(struct gsm_mux *gsm)
1653{
1654 struct gsm_dlci *dlci;
1655 u8 cr;
1656 int address;
1657 /* We have to sneak a look at the packet body to do the FCS.
1658 A somewhat layering violation in the spec */
1659
1660 if ((gsm->control & ~PF) == UI)
1661 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len);
Alan Coxc2f2f002010-11-04 15:17:03 +00001662 /* generate final CRC with received FCS */
1663 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs);
Alan Coxe1eaea42010-03-26 11:32:54 +00001664 if (gsm->fcs != GOOD_FCS) {
1665 gsm->bad_fcs++;
1666 if (debug & 4)
Alan Cox5f9a31d2010-11-04 15:17:27 +00001667 pr_debug("BAD FCS %02x\n", gsm->fcs);
Alan Coxe1eaea42010-03-26 11:32:54 +00001668 return;
1669 }
1670 address = gsm->address >> 1;
1671 if (address >= NUM_DLCI)
1672 goto invalid;
1673
1674 cr = gsm->address & 1; /* C/R bit */
1675
1676 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
1677
1678 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */
1679 dlci = gsm->dlci[address];
1680
1681 switch (gsm->control) {
1682 case SABM|PF:
1683 if (cr == 0)
1684 goto invalid;
1685 if (dlci == NULL)
1686 dlci = gsm_dlci_alloc(gsm, address);
1687 if (dlci == NULL)
1688 return;
1689 if (dlci->dead)
1690 gsm_response(gsm, address, DM);
1691 else {
1692 gsm_response(gsm, address, UA);
1693 gsm_dlci_open(dlci);
1694 }
1695 break;
1696 case DISC|PF:
1697 if (cr == 0)
1698 goto invalid;
1699 if (dlci == NULL || dlci->state == DLCI_CLOSED) {
1700 gsm_response(gsm, address, DM);
1701 return;
1702 }
1703 /* Real close complete */
1704 gsm_response(gsm, address, UA);
1705 gsm_dlci_close(dlci);
1706 break;
1707 case UA:
1708 case UA|PF:
1709 if (cr == 0 || dlci == NULL)
1710 break;
1711 switch (dlci->state) {
1712 case DLCI_CLOSING:
1713 gsm_dlci_close(dlci);
1714 break;
1715 case DLCI_OPENING:
1716 gsm_dlci_open(dlci);
1717 break;
1718 }
1719 break;
1720 case DM: /* DM can be valid unsolicited */
1721 case DM|PF:
1722 if (cr)
1723 goto invalid;
1724 if (dlci == NULL)
1725 return;
1726 gsm_dlci_close(dlci);
1727 break;
1728 case UI:
1729 case UI|PF:
1730 case UIH:
1731 case UIH|PF:
1732#if 0
1733 if (cr)
1734 goto invalid;
1735#endif
1736 if (dlci == NULL || dlci->state != DLCI_OPEN) {
1737 gsm_command(gsm, address, DM|PF);
1738 return;
1739 }
1740 dlci->data(dlci, gsm->buf, gsm->len);
1741 break;
1742 default:
1743 goto invalid;
1744 }
1745 return;
1746invalid:
1747 gsm->malformed++;
1748 return;
1749}
1750
1751
1752/**
1753 * gsm0_receive - perform processing for non-transparency
1754 * @gsm: gsm data for this ldisc instance
1755 * @c: character
1756 *
1757 * Receive bytes in gsm mode 0
1758 */
1759
1760static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
1761{
Alan Coxc2f2f002010-11-04 15:17:03 +00001762 unsigned int len;
1763
Alan Coxe1eaea42010-03-26 11:32:54 +00001764 switch (gsm->state) {
1765 case GSM_SEARCH: /* SOF marker */
1766 if (c == GSM0_SOF) {
1767 gsm->state = GSM_ADDRESS;
1768 gsm->address = 0;
1769 gsm->len = 0;
1770 gsm->fcs = INIT_FCS;
1771 }
Alan Coxc2f2f002010-11-04 15:17:03 +00001772 break;
1773 case GSM_ADDRESS: /* Address EA */
Alan Coxe1eaea42010-03-26 11:32:54 +00001774 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1775 if (gsm_read_ea(&gsm->address, c))
1776 gsm->state = GSM_CONTROL;
1777 break;
1778 case GSM_CONTROL: /* Control Byte */
1779 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1780 gsm->control = c;
Alan Coxc2f2f002010-11-04 15:17:03 +00001781 gsm->state = GSM_LEN0;
Alan Coxe1eaea42010-03-26 11:32:54 +00001782 break;
Alan Coxc2f2f002010-11-04 15:17:03 +00001783 case GSM_LEN0: /* Length EA */
Alan Coxe1eaea42010-03-26 11:32:54 +00001784 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1785 if (gsm_read_ea(&gsm->len, c)) {
1786 if (gsm->len > gsm->mru) {
1787 gsm->bad_size++;
1788 gsm->state = GSM_SEARCH;
1789 break;
1790 }
1791 gsm->count = 0;
Alan Coxc2f2f002010-11-04 15:17:03 +00001792 if (!gsm->len)
1793 gsm->state = GSM_FCS;
1794 else
1795 gsm->state = GSM_DATA;
1796 break;
Alan Coxe1eaea42010-03-26 11:32:54 +00001797 }
Alan Coxc2f2f002010-11-04 15:17:03 +00001798 gsm->state = GSM_LEN1;
1799 break;
1800 case GSM_LEN1:
1801 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1802 len = c;
1803 gsm->len |= len << 7;
1804 if (gsm->len > gsm->mru) {
1805 gsm->bad_size++;
1806 gsm->state = GSM_SEARCH;
1807 break;
1808 }
1809 gsm->count = 0;
1810 if (!gsm->len)
1811 gsm->state = GSM_FCS;
1812 else
1813 gsm->state = GSM_DATA;
Alan Coxe1eaea42010-03-26 11:32:54 +00001814 break;
1815 case GSM_DATA: /* Data */
1816 gsm->buf[gsm->count++] = c;
1817 if (gsm->count == gsm->len)
1818 gsm->state = GSM_FCS;
1819 break;
1820 case GSM_FCS: /* FCS follows the packet */
Alan Coxc2f2f002010-11-04 15:17:03 +00001821 gsm->received_fcs = c;
1822 if (c == GSM0_SOF) {
1823 gsm->state = GSM_SEARCH;
1824 break;
1825 }
Alan Coxe1eaea42010-03-26 11:32:54 +00001826 gsm_queue(gsm);
Alan Coxc2f2f002010-11-04 15:17:03 +00001827 gsm->state = GSM_SSOF;
1828 break;
1829 case GSM_SSOF:
1830 if (c == GSM0_SOF) {
1831 gsm->state = GSM_SEARCH;
1832 break;
1833 }
Alan Coxe1eaea42010-03-26 11:32:54 +00001834 break;
1835 }
1836}
1837
1838/**
Alan Coxc2f2f002010-11-04 15:17:03 +00001839 * gsm1_receive - perform processing for non-transparency
Alan Coxe1eaea42010-03-26 11:32:54 +00001840 * @gsm: gsm data for this ldisc instance
1841 * @c: character
1842 *
1843 * Receive bytes in mode 1 (Advanced option)
1844 */
1845
1846static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
1847{
1848 if (c == GSM1_SOF) {
1849 /* EOF is only valid in frame if we have got to the data state
1850 and received at least one byte (the FCS) */
1851 if (gsm->state == GSM_DATA && gsm->count) {
1852 /* Extract the FCS */
1853 gsm->count--;
1854 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
1855 gsm->len = gsm->count;
1856 gsm_queue(gsm);
1857 gsm->state = GSM_START;
1858 return;
1859 }
1860 /* Any partial frame was a runt so go back to start */
1861 if (gsm->state != GSM_START) {
1862 gsm->malformed++;
1863 gsm->state = GSM_START;
1864 }
1865 /* A SOF in GSM_START means we are still reading idling or
1866 framing bytes */
1867 return;
1868 }
1869
1870 if (c == GSM1_ESCAPE) {
1871 gsm->escape = 1;
1872 return;
1873 }
1874
1875 /* Only an unescaped SOF gets us out of GSM search */
1876 if (gsm->state == GSM_SEARCH)
1877 return;
1878
1879 if (gsm->escape) {
1880 c ^= GSM1_ESCAPE_BITS;
1881 gsm->escape = 0;
1882 }
1883 switch (gsm->state) {
1884 case GSM_START: /* First byte after SOF */
1885 gsm->address = 0;
1886 gsm->state = GSM_ADDRESS;
1887 gsm->fcs = INIT_FCS;
1888 /* Drop through */
1889 case GSM_ADDRESS: /* Address continuation */
1890 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1891 if (gsm_read_ea(&gsm->address, c))
1892 gsm->state = GSM_CONTROL;
1893 break;
1894 case GSM_CONTROL: /* Control Byte */
1895 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1896 gsm->control = c;
1897 gsm->count = 0;
1898 gsm->state = GSM_DATA;
1899 break;
1900 case GSM_DATA: /* Data */
Alan Cox5f9a31d2010-11-04 15:17:27 +00001901 if (gsm->count > gsm->mru) { /* Allow one for the FCS */
Alan Coxe1eaea42010-03-26 11:32:54 +00001902 gsm->state = GSM_OVERRUN;
1903 gsm->bad_size++;
1904 } else
1905 gsm->buf[gsm->count++] = c;
1906 break;
1907 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */
1908 break;
1909 }
1910}
1911
1912/**
1913 * gsm_error - handle tty error
1914 * @gsm: ldisc data
1915 * @data: byte received (may be invalid)
1916 * @flag: error received
1917 *
1918 * Handle an error in the receipt of data for a frame. Currently we just
1919 * go back to hunting for a SOF.
1920 *
1921 * FIXME: better diagnostics ?
1922 */
1923
1924static void gsm_error(struct gsm_mux *gsm,
1925 unsigned char data, unsigned char flag)
1926{
1927 gsm->state = GSM_SEARCH;
1928 gsm->io_error++;
1929}
1930
1931/**
1932 * gsm_cleanup_mux - generic GSM protocol cleanup
1933 * @gsm: our mux
1934 *
1935 * Clean up the bits of the mux which are the same for all framing
1936 * protocols. Remove the mux from the mux table, stop all the timers
1937 * and then shut down each device hanging up the channels as we go.
1938 */
1939
1940void gsm_cleanup_mux(struct gsm_mux *gsm)
1941{
1942 int i;
1943 struct gsm_dlci *dlci = gsm->dlci[0];
1944 struct gsm_msg *txq;
1945
1946 gsm->dead = 1;
1947
1948 spin_lock(&gsm_mux_lock);
1949 for (i = 0; i < MAX_MUX; i++) {
1950 if (gsm_mux[i] == gsm) {
1951 gsm_mux[i] = NULL;
1952 break;
1953 }
1954 }
1955 spin_unlock(&gsm_mux_lock);
1956 WARN_ON(i == MAX_MUX);
1957
1958 del_timer_sync(&gsm->t2_timer);
1959 /* Now we are sure T2 has stopped */
1960 if (dlci) {
1961 dlci->dead = 1;
1962 gsm_dlci_begin_close(dlci);
1963 wait_event_interruptible(gsm->event,
1964 dlci->state == DLCI_CLOSED);
1965 }
1966 /* Free up any link layer users */
1967 for (i = 0; i < NUM_DLCI; i++)
1968 if (gsm->dlci[i])
1969 gsm_dlci_free(gsm->dlci[i]);
1970 /* Now wipe the queues */
1971 for (txq = gsm->tx_head; txq != NULL; txq = gsm->tx_head) {
1972 gsm->tx_head = txq->next;
1973 kfree(txq);
1974 }
1975 gsm->tx_tail = NULL;
1976}
1977EXPORT_SYMBOL_GPL(gsm_cleanup_mux);
1978
1979/**
1980 * gsm_activate_mux - generic GSM setup
1981 * @gsm: our mux
1982 *
1983 * Set up the bits of the mux which are the same for all framing
1984 * protocols. Add the mux to the mux table so it can be opened and
1985 * finally kick off connecting to DLCI 0 on the modem.
1986 */
1987
1988int gsm_activate_mux(struct gsm_mux *gsm)
1989{
1990 struct gsm_dlci *dlci;
1991 int i = 0;
1992
1993 init_timer(&gsm->t2_timer);
1994 gsm->t2_timer.function = gsm_control_retransmit;
1995 gsm->t2_timer.data = (unsigned long)gsm;
1996 init_waitqueue_head(&gsm->event);
1997 spin_lock_init(&gsm->control_lock);
1998 spin_lock_init(&gsm->tx_lock);
1999
2000 if (gsm->encoding == 0)
2001 gsm->receive = gsm0_receive;
2002 else
2003 gsm->receive = gsm1_receive;
2004 gsm->error = gsm_error;
2005
2006 spin_lock(&gsm_mux_lock);
2007 for (i = 0; i < MAX_MUX; i++) {
2008 if (gsm_mux[i] == NULL) {
2009 gsm_mux[i] = gsm;
2010 break;
2011 }
2012 }
2013 spin_unlock(&gsm_mux_lock);
2014 if (i == MAX_MUX)
2015 return -EBUSY;
2016
2017 dlci = gsm_dlci_alloc(gsm, 0);
2018 if (dlci == NULL)
2019 return -ENOMEM;
2020 gsm->dead = 0; /* Tty opens are now permissible */
2021 return 0;
2022}
2023EXPORT_SYMBOL_GPL(gsm_activate_mux);
2024
2025/**
2026 * gsm_free_mux - free up a mux
2027 * @mux: mux to free
2028 *
2029 * Dispose of allocated resources for a dead mux. No refcounting
2030 * at present so the mux must be truely dead.
2031 */
2032void gsm_free_mux(struct gsm_mux *gsm)
2033{
2034 kfree(gsm->txframe);
2035 kfree(gsm->buf);
2036 kfree(gsm);
2037}
2038EXPORT_SYMBOL_GPL(gsm_free_mux);
2039
2040/**
2041 * gsm_alloc_mux - allocate a mux
2042 *
2043 * Creates a new mux ready for activation.
2044 */
2045
2046struct gsm_mux *gsm_alloc_mux(void)
2047{
2048 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
2049 if (gsm == NULL)
2050 return NULL;
2051 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL);
2052 if (gsm->buf == NULL) {
2053 kfree(gsm);
2054 return NULL;
2055 }
2056 gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL);
2057 if (gsm->txframe == NULL) {
2058 kfree(gsm->buf);
2059 kfree(gsm);
2060 return NULL;
2061 }
2062 spin_lock_init(&gsm->lock);
2063
2064 gsm->t1 = T1;
2065 gsm->t2 = T2;
2066 gsm->n2 = N2;
2067 gsm->ftype = UIH;
2068 gsm->initiator = 0;
2069 gsm->adaption = 1;
2070 gsm->encoding = 1;
2071 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
2072 gsm->mtu = 64;
2073 gsm->dead = 1; /* Avoid early tty opens */
2074
2075 return gsm;
2076}
2077EXPORT_SYMBOL_GPL(gsm_alloc_mux);
2078
Alan Coxe1eaea42010-03-26 11:32:54 +00002079/**
2080 * gsmld_output - write to link
2081 * @gsm: our mux
2082 * @data: bytes to output
2083 * @len: size
2084 *
2085 * Write a block of data from the GSM mux to the data channel. This
2086 * will eventually be serialized from above but at the moment isn't.
2087 */
2088
2089static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
2090{
2091 if (tty_write_room(gsm->tty) < len) {
2092 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
2093 return -ENOSPC;
2094 }
2095 if (debug & 4) {
Alan Cox5f9a31d2010-11-04 15:17:27 +00002096 pr_debug("-->%d bytes out\n", len);
Alan Coxe1eaea42010-03-26 11:32:54 +00002097 hex_packet(data, len);
2098 }
2099 gsm->tty->ops->write(gsm->tty, data, len);
2100 return len;
2101}
2102
2103/**
2104 * gsmld_attach_gsm - mode set up
2105 * @tty: our tty structure
2106 * @gsm: our mux
2107 *
2108 * Set up the MUX for basic mode and commence connecting to the
2109 * modem. Currently called from the line discipline set up but
2110 * will need moving to an ioctl path.
2111 */
2112
2113static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2114{
2115 int ret;
2116
2117 gsm->tty = tty_kref_get(tty);
2118 gsm->output = gsmld_output;
2119 ret = gsm_activate_mux(gsm);
2120 if (ret != 0)
2121 tty_kref_put(gsm->tty);
2122 return ret;
2123}
2124
2125
2126/**
2127 * gsmld_detach_gsm - stop doing 0710 mux
2128 * @tty: tty atttached to the mux
2129 * @gsm: mux
2130 *
2131 * Shutdown and then clean up the resources used by the line discipline
2132 */
2133
2134static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2135{
2136 WARN_ON(tty != gsm->tty);
2137 gsm_cleanup_mux(gsm);
2138 tty_kref_put(gsm->tty);
2139 gsm->tty = NULL;
2140}
2141
2142static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
2143 char *fp, int count)
2144{
2145 struct gsm_mux *gsm = tty->disc_data;
2146 const unsigned char *dp;
2147 char *f;
2148 int i;
2149 char buf[64];
2150 char flags;
2151
2152 if (debug & 4) {
Alan Cox5f9a31d2010-11-04 15:17:27 +00002153 pr_debug("Inbytes %dd\n", count);
Alan Coxe1eaea42010-03-26 11:32:54 +00002154 hex_packet(cp, count);
2155 }
2156
2157 for (i = count, dp = cp, f = fp; i; i--, dp++) {
2158 flags = *f++;
2159 switch (flags) {
2160 case TTY_NORMAL:
2161 gsm->receive(gsm, *dp);
2162 break;
2163 case TTY_OVERRUN:
2164 case TTY_BREAK:
2165 case TTY_PARITY:
2166 case TTY_FRAME:
2167 gsm->error(gsm, *dp, flags);
2168 break;
2169 default:
Alan Cox5f9a31d2010-11-04 15:17:27 +00002170 WARN_ONCE("%s: unknown flag %d\n",
Alan Coxe1eaea42010-03-26 11:32:54 +00002171 tty_name(tty, buf), flags);
2172 break;
2173 }
2174 }
2175 /* FASYNC if needed ? */
2176 /* If clogged call tty_throttle(tty); */
2177}
2178
2179/**
2180 * gsmld_chars_in_buffer - report available bytes
2181 * @tty: tty device
2182 *
2183 * Report the number of characters buffered to be delivered to user
2184 * at this instant in time.
2185 *
2186 * Locking: gsm lock
2187 */
2188
2189static ssize_t gsmld_chars_in_buffer(struct tty_struct *tty)
2190{
2191 return 0;
2192}
2193
2194/**
2195 * gsmld_flush_buffer - clean input queue
2196 * @tty: terminal device
2197 *
2198 * Flush the input buffer. Called when the line discipline is
2199 * being closed, when the tty layer wants the buffer flushed (eg
2200 * at hangup).
2201 */
2202
2203static void gsmld_flush_buffer(struct tty_struct *tty)
2204{
2205}
2206
2207/**
2208 * gsmld_close - close the ldisc for this tty
2209 * @tty: device
2210 *
2211 * Called from the terminal layer when this line discipline is
2212 * being shut down, either because of a close or becsuse of a
2213 * discipline change. The function will not be called while other
2214 * ldisc methods are in progress.
2215 */
2216
2217static void gsmld_close(struct tty_struct *tty)
2218{
2219 struct gsm_mux *gsm = tty->disc_data;
2220
2221 gsmld_detach_gsm(tty, gsm);
2222
2223 gsmld_flush_buffer(tty);
2224 /* Do other clean up here */
2225 gsm_free_mux(gsm);
2226}
2227
2228/**
2229 * gsmld_open - open an ldisc
2230 * @tty: terminal to open
2231 *
2232 * Called when this line discipline is being attached to the
2233 * terminal device. Can sleep. Called serialized so that no
2234 * other events will occur in parallel. No further open will occur
2235 * until a close.
2236 */
2237
2238static int gsmld_open(struct tty_struct *tty)
2239{
2240 struct gsm_mux *gsm;
2241
2242 if (tty->ops->write == NULL)
2243 return -EINVAL;
2244
2245 /* Attach our ldisc data */
2246 gsm = gsm_alloc_mux();
2247 if (gsm == NULL)
2248 return -ENOMEM;
2249
2250 tty->disc_data = gsm;
2251 tty->receive_room = 65536;
2252
2253 /* Attach the initial passive connection */
2254 gsm->encoding = 1;
2255 return gsmld_attach_gsm(tty, gsm);
2256}
2257
2258/**
2259 * gsmld_write_wakeup - asynchronous I/O notifier
2260 * @tty: tty device
2261 *
2262 * Required for the ptys, serial driver etc. since processes
2263 * that attach themselves to the master and rely on ASYNC
2264 * IO must be woken up
2265 */
2266
2267static void gsmld_write_wakeup(struct tty_struct *tty)
2268{
2269 struct gsm_mux *gsm = tty->disc_data;
Dan Carpenter328be392010-05-25 11:37:17 +02002270 unsigned long flags;
Alan Coxe1eaea42010-03-26 11:32:54 +00002271
2272 /* Queue poll */
2273 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2274 gsm_data_kick(gsm);
Dan Carpenter328be392010-05-25 11:37:17 +02002275 if (gsm->tx_bytes < TX_THRESH_LO) {
2276 spin_lock_irqsave(&gsm->tx_lock, flags);
Alan Coxe1eaea42010-03-26 11:32:54 +00002277 gsm_dlci_data_sweep(gsm);
Dan Carpenter328be392010-05-25 11:37:17 +02002278 spin_unlock_irqrestore(&gsm->tx_lock, flags);
2279 }
Alan Coxe1eaea42010-03-26 11:32:54 +00002280}
2281
2282/**
2283 * gsmld_read - read function for tty
2284 * @tty: tty device
2285 * @file: file object
2286 * @buf: userspace buffer pointer
2287 * @nr: size of I/O
2288 *
2289 * Perform reads for the line discipline. We are guaranteed that the
2290 * line discipline will not be closed under us but we may get multiple
2291 * parallel readers and must handle this ourselves. We may also get
2292 * a hangup. Always called in user context, may sleep.
2293 *
2294 * This code must be sure never to sleep through a hangup.
2295 */
2296
2297static ssize_t gsmld_read(struct tty_struct *tty, struct file *file,
2298 unsigned char __user *buf, size_t nr)
2299{
2300 return -EOPNOTSUPP;
2301}
2302
2303/**
2304 * gsmld_write - write function for tty
2305 * @tty: tty device
2306 * @file: file object
2307 * @buf: userspace buffer pointer
2308 * @nr: size of I/O
2309 *
2310 * Called when the owner of the device wants to send a frame
2311 * itself (or some other control data). The data is transferred
2312 * as-is and must be properly framed and checksummed as appropriate
2313 * by userspace. Frames are either sent whole or not at all as this
2314 * avoids pain user side.
2315 */
2316
2317static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
2318 const unsigned char *buf, size_t nr)
2319{
2320 int space = tty_write_room(tty);
2321 if (space >= nr)
2322 return tty->ops->write(tty, buf, nr);
2323 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2324 return -ENOBUFS;
2325}
2326
2327/**
2328 * gsmld_poll - poll method for N_GSM0710
2329 * @tty: terminal device
2330 * @file: file accessing it
2331 * @wait: poll table
2332 *
2333 * Called when the line discipline is asked to poll() for data or
2334 * for special events. This code is not serialized with respect to
2335 * other events save open/close.
2336 *
2337 * This code must be sure never to sleep through a hangup.
2338 * Called without the kernel lock held - fine
2339 */
2340
2341static unsigned int gsmld_poll(struct tty_struct *tty, struct file *file,
2342 poll_table *wait)
2343{
2344 unsigned int mask = 0;
2345 struct gsm_mux *gsm = tty->disc_data;
2346
2347 poll_wait(file, &tty->read_wait, wait);
2348 poll_wait(file, &tty->write_wait, wait);
2349 if (tty_hung_up_p(file))
2350 mask |= POLLHUP;
2351 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
2352 mask |= POLLOUT | POLLWRNORM;
2353 if (gsm->dead)
2354 mask |= POLLHUP;
2355 return mask;
2356}
2357
2358static int gsmld_config(struct tty_struct *tty, struct gsm_mux *gsm,
2359 struct gsm_config *c)
2360{
2361 int need_close = 0;
2362 int need_restart = 0;
2363
2364 /* Stuff we don't support yet - UI or I frame transport, windowing */
Alan Cox5f9a31d2010-11-04 15:17:27 +00002365 if ((c->adaption != 1 && c->adaption != 2) || c->k)
Alan Coxe1eaea42010-03-26 11:32:54 +00002366 return -EOPNOTSUPP;
2367 /* Check the MRU/MTU range looks sane */
2368 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8)
2369 return -EINVAL;
2370 if (c->n2 < 3)
2371 return -EINVAL;
2372 if (c->encapsulation > 1) /* Basic, advanced, no I */
2373 return -EINVAL;
2374 if (c->initiator > 1)
2375 return -EINVAL;
2376 if (c->i == 0 || c->i > 2) /* UIH and UI only */
2377 return -EINVAL;
2378 /*
2379 * See what is needed for reconfiguration
2380 */
2381
2382 /* Timing fields */
2383 if (c->t1 != 0 && c->t1 != gsm->t1)
2384 need_restart = 1;
2385 if (c->t2 != 0 && c->t2 != gsm->t2)
2386 need_restart = 1;
2387 if (c->encapsulation != gsm->encoding)
2388 need_restart = 1;
2389 if (c->adaption != gsm->adaption)
2390 need_restart = 1;
2391 /* Requires care */
2392 if (c->initiator != gsm->initiator)
2393 need_close = 1;
2394 if (c->mru != gsm->mru)
2395 need_restart = 1;
2396 if (c->mtu != gsm->mtu)
2397 need_restart = 1;
2398
2399 /*
2400 * Close down what is needed, restart and initiate the new
2401 * configuration
2402 */
2403
2404 if (need_close || need_restart) {
2405 gsm_dlci_begin_close(gsm->dlci[0]);
2406 /* This will timeout if the link is down due to N2 expiring */
2407 wait_event_interruptible(gsm->event,
2408 gsm->dlci[0]->state == DLCI_CLOSED);
2409 if (signal_pending(current))
2410 return -EINTR;
2411 }
2412 if (need_restart)
2413 gsm_cleanup_mux(gsm);
2414
2415 gsm->initiator = c->initiator;
2416 gsm->mru = c->mru;
Ken Mills91f78f32011-01-25 14:17:45 +00002417 gsm->mtu = c->mtu;
Alan Coxe1eaea42010-03-26 11:32:54 +00002418 gsm->encoding = c->encapsulation;
2419 gsm->adaption = c->adaption;
Ken Mills820e62e2010-11-04 15:16:24 +00002420 gsm->n2 = c->n2;
Alan Coxe1eaea42010-03-26 11:32:54 +00002421
2422 if (c->i == 1)
2423 gsm->ftype = UIH;
2424 else if (c->i == 2)
2425 gsm->ftype = UI;
2426
2427 if (c->t1)
2428 gsm->t1 = c->t1;
2429 if (c->t2)
2430 gsm->t2 = c->t2;
2431
2432 /* FIXME: We need to separate activation/deactivation from adding
2433 and removing from the mux array */
2434 if (need_restart)
2435 gsm_activate_mux(gsm);
2436 if (gsm->initiator && need_close)
2437 gsm_dlci_begin_open(gsm->dlci[0]);
2438 return 0;
2439}
2440
2441static int gsmld_ioctl(struct tty_struct *tty, struct file *file,
2442 unsigned int cmd, unsigned long arg)
2443{
2444 struct gsm_config c;
2445 struct gsm_mux *gsm = tty->disc_data;
2446
2447 switch (cmd) {
2448 case GSMIOC_GETCONF:
2449 memset(&c, 0, sizeof(c));
2450 c.adaption = gsm->adaption;
2451 c.encapsulation = gsm->encoding;
2452 c.initiator = gsm->initiator;
2453 c.t1 = gsm->t1;
2454 c.t2 = gsm->t2;
2455 c.t3 = 0; /* Not supported */
2456 c.n2 = gsm->n2;
2457 if (gsm->ftype == UIH)
2458 c.i = 1;
2459 else
2460 c.i = 2;
Alan Cox5f9a31d2010-11-04 15:17:27 +00002461 pr_debug("Ftype %d i %d\n", gsm->ftype, c.i);
Alan Coxe1eaea42010-03-26 11:32:54 +00002462 c.mru = gsm->mru;
2463 c.mtu = gsm->mtu;
2464 c.k = 0;
2465 if (copy_to_user((void *)arg, &c, sizeof(c)))
2466 return -EFAULT;
2467 return 0;
2468 case GSMIOC_SETCONF:
2469 if (copy_from_user(&c, (void *)arg, sizeof(c)))
2470 return -EFAULT;
2471 return gsmld_config(tty, gsm, &c);
2472 default:
2473 return n_tty_ioctl_helper(tty, file, cmd, arg);
2474 }
2475}
2476
2477
2478/* Line discipline for real tty */
2479struct tty_ldisc_ops tty_ldisc_packet = {
2480 .owner = THIS_MODULE,
2481 .magic = TTY_LDISC_MAGIC,
2482 .name = "n_gsm",
2483 .open = gsmld_open,
2484 .close = gsmld_close,
2485 .flush_buffer = gsmld_flush_buffer,
2486 .chars_in_buffer = gsmld_chars_in_buffer,
2487 .read = gsmld_read,
2488 .write = gsmld_write,
2489 .ioctl = gsmld_ioctl,
2490 .poll = gsmld_poll,
2491 .receive_buf = gsmld_receive_buf,
2492 .write_wakeup = gsmld_write_wakeup
2493};
2494
2495/*
2496 * Virtual tty side
2497 */
2498
2499#define TX_SIZE 512
2500
2501static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk)
2502{
2503 u8 modembits[5];
2504 struct gsm_control *ctrl;
2505 int len = 2;
2506
2507 if (brk)
2508 len++;
2509
2510 modembits[0] = len << 1 | EA; /* Data bytes */
2511 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */
2512 modembits[2] = gsm_encode_modem(dlci) << 1 | EA;
2513 if (brk)
2514 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */
2515 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1);
2516 if (ctrl == NULL)
2517 return -ENOMEM;
2518 return gsm_control_wait(dlci->gsm, ctrl);
2519}
2520
2521static int gsm_carrier_raised(struct tty_port *port)
2522{
2523 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2524 /* Not yet open so no carrier info */
2525 if (dlci->state != DLCI_OPEN)
2526 return 0;
2527 if (debug & 2)
2528 return 1;
2529 return dlci->modem_rx & TIOCM_CD;
2530}
2531
2532static void gsm_dtr_rts(struct tty_port *port, int onoff)
2533{
2534 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2535 unsigned int modem_tx = dlci->modem_tx;
2536 if (onoff)
2537 modem_tx |= TIOCM_DTR | TIOCM_RTS;
2538 else
2539 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
2540 if (modem_tx != dlci->modem_tx) {
2541 dlci->modem_tx = modem_tx;
2542 gsmtty_modem_update(dlci, 0);
2543 }
2544}
2545
2546static const struct tty_port_operations gsm_port_ops = {
2547 .carrier_raised = gsm_carrier_raised,
2548 .dtr_rts = gsm_dtr_rts,
2549};
2550
2551
2552static int gsmtty_open(struct tty_struct *tty, struct file *filp)
2553{
2554 struct gsm_mux *gsm;
2555 struct gsm_dlci *dlci;
2556 struct tty_port *port;
2557 unsigned int line = tty->index;
2558 unsigned int mux = line >> 6;
2559
2560 line = line & 0x3F;
2561
2562 if (mux >= MAX_MUX)
2563 return -ENXIO;
2564 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
2565 if (gsm_mux[mux] == NULL)
2566 return -EUNATCH;
2567 if (line == 0 || line > 61) /* 62/63 reserved */
2568 return -ECHRNG;
2569 gsm = gsm_mux[mux];
2570 if (gsm->dead)
2571 return -EL2HLT;
2572 dlci = gsm->dlci[line];
2573 if (dlci == NULL)
2574 dlci = gsm_dlci_alloc(gsm, line);
2575 if (dlci == NULL)
2576 return -ENOMEM;
2577 port = &dlci->port;
2578 port->count++;
2579 tty->driver_data = dlci;
2580 tty_port_tty_set(port, tty);
2581
2582 dlci->modem_rx = 0;
2583 /* We could in theory open and close before we wait - eg if we get
2584 a DM straight back. This is ok as that will have caused a hangup */
2585 set_bit(ASYNCB_INITIALIZED, &port->flags);
2586 /* Start sending off SABM messages */
2587 gsm_dlci_begin_open(dlci);
2588 /* And wait for virtual carrier */
2589 return tty_port_block_til_ready(port, tty, filp);
2590}
2591
2592static void gsmtty_close(struct tty_struct *tty, struct file *filp)
2593{
2594 struct gsm_dlci *dlci = tty->driver_data;
2595 if (dlci == NULL)
2596 return;
2597 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
2598 return;
2599 gsm_dlci_begin_close(dlci);
2600 tty_port_close_end(&dlci->port, tty);
2601 tty_port_tty_set(&dlci->port, NULL);
2602}
2603
2604static void gsmtty_hangup(struct tty_struct *tty)
2605{
2606 struct gsm_dlci *dlci = tty->driver_data;
2607 tty_port_hangup(&dlci->port);
2608 gsm_dlci_begin_close(dlci);
2609}
2610
2611static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf,
2612 int len)
2613{
2614 struct gsm_dlci *dlci = tty->driver_data;
2615 /* Stuff the bytes into the fifo queue */
2616 int sent = kfifo_in_locked(dlci->fifo, buf, len, &dlci->lock);
2617 /* Need to kick the channel */
2618 gsm_dlci_data_kick(dlci);
2619 return sent;
2620}
2621
2622static int gsmtty_write_room(struct tty_struct *tty)
2623{
2624 struct gsm_dlci *dlci = tty->driver_data;
2625 return TX_SIZE - kfifo_len(dlci->fifo);
2626}
2627
2628static int gsmtty_chars_in_buffer(struct tty_struct *tty)
2629{
2630 struct gsm_dlci *dlci = tty->driver_data;
2631 return kfifo_len(dlci->fifo);
2632}
2633
2634static void gsmtty_flush_buffer(struct tty_struct *tty)
2635{
2636 struct gsm_dlci *dlci = tty->driver_data;
2637 /* Caution needed: If we implement reliable transport classes
2638 then the data being transmitted can't simply be junked once
2639 it has first hit the stack. Until then we can just blow it
2640 away */
2641 kfifo_reset(dlci->fifo);
2642 /* Need to unhook this DLCI from the transmit queue logic */
2643}
2644
2645static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
2646{
2647 /* The FIFO handles the queue so the kernel will do the right
2648 thing waiting on chars_in_buffer before calling us. No work
2649 to do here */
2650}
2651
2652static int gsmtty_tiocmget(struct tty_struct *tty, struct file *filp)
2653{
2654 struct gsm_dlci *dlci = tty->driver_data;
2655 return dlci->modem_rx;
2656}
2657
2658static int gsmtty_tiocmset(struct tty_struct *tty, struct file *filp,
2659 unsigned int set, unsigned int clear)
2660{
2661 struct gsm_dlci *dlci = tty->driver_data;
2662 unsigned int modem_tx = dlci->modem_tx;
2663
2664 modem_tx &= clear;
2665 modem_tx |= set;
2666
2667 if (modem_tx != dlci->modem_tx) {
2668 dlci->modem_tx = modem_tx;
2669 return gsmtty_modem_update(dlci, 0);
2670 }
2671 return 0;
2672}
2673
2674
2675static int gsmtty_ioctl(struct tty_struct *tty, struct file *filp,
2676 unsigned int cmd, unsigned long arg)
2677{
2678 return -ENOIOCTLCMD;
2679}
2680
2681static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old)
2682{
2683 /* For the moment its fixed. In actual fact the speed information
2684 for the virtual channel can be propogated in both directions by
2685 the RPN control message. This however rapidly gets nasty as we
2686 then have to remap modem signals each way according to whether
2687 our virtual cable is null modem etc .. */
2688 tty_termios_copy_hw(tty->termios, old);
2689}
2690
2691static void gsmtty_throttle(struct tty_struct *tty)
2692{
2693 struct gsm_dlci *dlci = tty->driver_data;
2694 if (tty->termios->c_cflag & CRTSCTS)
2695 dlci->modem_tx &= ~TIOCM_DTR;
2696 dlci->throttled = 1;
2697 /* Send an MSC with DTR cleared */
2698 gsmtty_modem_update(dlci, 0);
2699}
2700
2701static void gsmtty_unthrottle(struct tty_struct *tty)
2702{
2703 struct gsm_dlci *dlci = tty->driver_data;
2704 if (tty->termios->c_cflag & CRTSCTS)
2705 dlci->modem_tx |= TIOCM_DTR;
2706 dlci->throttled = 0;
2707 /* Send an MSC with DTR set */
2708 gsmtty_modem_update(dlci, 0);
2709}
2710
2711static int gsmtty_break_ctl(struct tty_struct *tty, int state)
2712{
2713 struct gsm_dlci *dlci = tty->driver_data;
2714 int encode = 0; /* Off */
2715
2716 if (state == -1) /* "On indefinitely" - we can't encode this
2717 properly */
2718 encode = 0x0F;
2719 else if (state > 0) {
2720 encode = state / 200; /* mS to encoding */
2721 if (encode > 0x0F)
2722 encode = 0x0F; /* Best effort */
2723 }
2724 return gsmtty_modem_update(dlci, encode);
2725}
2726
2727static struct tty_driver *gsm_tty_driver;
2728
2729/* Virtual ttys for the demux */
2730static const struct tty_operations gsmtty_ops = {
2731 .open = gsmtty_open,
2732 .close = gsmtty_close,
2733 .write = gsmtty_write,
2734 .write_room = gsmtty_write_room,
2735 .chars_in_buffer = gsmtty_chars_in_buffer,
2736 .flush_buffer = gsmtty_flush_buffer,
2737 .ioctl = gsmtty_ioctl,
2738 .throttle = gsmtty_throttle,
2739 .unthrottle = gsmtty_unthrottle,
2740 .set_termios = gsmtty_set_termios,
2741 .hangup = gsmtty_hangup,
2742 .wait_until_sent = gsmtty_wait_until_sent,
2743 .tiocmget = gsmtty_tiocmget,
2744 .tiocmset = gsmtty_tiocmset,
2745 .break_ctl = gsmtty_break_ctl,
2746};
2747
2748
2749
2750static int __init gsm_init(void)
2751{
2752 /* Fill in our line protocol discipline, and register it */
2753 int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet);
2754 if (status != 0) {
Alan Cox5f9a31d2010-11-04 15:17:27 +00002755 pr_err("n_gsm: can't register line discipline (err = %d)\n",
2756 status);
Alan Coxe1eaea42010-03-26 11:32:54 +00002757 return status;
2758 }
2759
2760 gsm_tty_driver = alloc_tty_driver(256);
2761 if (!gsm_tty_driver) {
2762 tty_unregister_ldisc(N_GSM0710);
Alan Cox5f9a31d2010-11-04 15:17:27 +00002763 pr_err("gsm_init: tty allocation failed.\n");
Alan Coxe1eaea42010-03-26 11:32:54 +00002764 return -EINVAL;
2765 }
2766 gsm_tty_driver->owner = THIS_MODULE;
2767 gsm_tty_driver->driver_name = "gsmtty";
2768 gsm_tty_driver->name = "gsmtty";
2769 gsm_tty_driver->major = 0; /* Dynamic */
2770 gsm_tty_driver->minor_start = 0;
2771 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
2772 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
2773 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV
Alan Cox5f9a31d2010-11-04 15:17:27 +00002774 | TTY_DRIVER_HARDWARE_BREAK;
Alan Coxe1eaea42010-03-26 11:32:54 +00002775 gsm_tty_driver->init_termios = tty_std_termios;
2776 /* Fixme */
2777 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
2778 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
2779
2780 spin_lock_init(&gsm_mux_lock);
2781
2782 if (tty_register_driver(gsm_tty_driver)) {
2783 put_tty_driver(gsm_tty_driver);
2784 tty_unregister_ldisc(N_GSM0710);
Alan Cox5f9a31d2010-11-04 15:17:27 +00002785 pr_err("gsm_init: tty registration failed.\n");
Alan Coxe1eaea42010-03-26 11:32:54 +00002786 return -EBUSY;
2787 }
Alan Cox5f9a31d2010-11-04 15:17:27 +00002788 pr_debug("gsm_init: loaded as %d,%d.\n",
2789 gsm_tty_driver->major, gsm_tty_driver->minor_start);
Alan Coxe1eaea42010-03-26 11:32:54 +00002790 return 0;
2791}
2792
2793static void __exit gsm_exit(void)
2794{
2795 int status = tty_unregister_ldisc(N_GSM0710);
2796 if (status != 0)
Alan Cox5f9a31d2010-11-04 15:17:27 +00002797 pr_err("n_gsm: can't unregister line discipline (err = %d)\n",
2798 status);
Alan Coxe1eaea42010-03-26 11:32:54 +00002799 tty_unregister_driver(gsm_tty_driver);
2800 put_tty_driver(gsm_tty_driver);
Alan Coxe1eaea42010-03-26 11:32:54 +00002801}
2802
2803module_init(gsm_init);
2804module_exit(gsm_exit);
2805
2806
2807MODULE_LICENSE("GPL");
2808MODULE_ALIAS_LDISC(N_GSM0710);