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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 ?
Alan Coxe1eaea42010-03-26 11:32:54 +000024 * Improve the tx engine
25 * Resolve tx side locking by adding a queue_head and routing
26 * all control traffic via it
27 * General tidy/document
28 * Review the locking/move to refcounts more (mux now moved to an
29 * alloc/free model ready)
30 * Use newest tty open/close port helpers and install hooks
31 * What to do about power functions ?
32 * Termios setting and negotiation
33 * Do we need a 'which mux are you' ioctl to correlate mux and tty sets
34 *
35 */
36
37#include <linux/types.h>
38#include <linux/major.h>
39#include <linux/errno.h>
40#include <linux/signal.h>
41#include <linux/fcntl.h>
42#include <linux/sched.h>
43#include <linux/interrupt.h>
44#include <linux/tty.h>
Alan Coxe1eaea42010-03-26 11:32:54 +000045#include <linux/ctype.h>
46#include <linux/mm.h>
47#include <linux/string.h>
48#include <linux/slab.h>
49#include <linux/poll.h>
50#include <linux/bitops.h>
51#include <linux/file.h>
52#include <linux/uaccess.h>
53#include <linux/module.h>
54#include <linux/timer.h>
55#include <linux/tty_flip.h>
56#include <linux/tty_driver.h>
57#include <linux/serial.h>
58#include <linux/kfifo.h>
59#include <linux/skbuff.h>
Russ Gorbybcd5abe2011-06-16 14:20:12 -070060#include <net/arp.h>
61#include <linux/ip.h>
62#include <linux/netdevice.h>
63#include <linux/etherdevice.h>
Alan Coxe1eaea42010-03-26 11:32:54 +000064#include <linux/gsmmux.h>
65
66static int debug;
67module_param(debug, int, 0600);
68
Alan Coxa8d12002011-11-08 18:02:10 +000069/* Defaults: these are from the specification */
70
71#define T1 10 /* 100mS */
72#define T2 34 /* 333mS */
73#define N2 3 /* Retry 3 times */
Alan Coxe1eaea42010-03-26 11:32:54 +000074
75/* Use long timers for testing at low speed with debug on */
76#ifdef DEBUG_TIMING
Alan Coxa8d12002011-11-08 18:02:10 +000077#define T1 100
78#define T2 200
Alan Coxe1eaea42010-03-26 11:32:54 +000079#endif
80
Alan Cox5f9a31d2010-11-04 15:17:27 +000081/*
Lucas De Marchi25985ed2011-03-30 22:57:33 -030082 * Semi-arbitrary buffer size limits. 0710 is normally run with 32-64 byte
Alan Cox5f9a31d2010-11-04 15:17:27 +000083 * limits so this is plenty
84 */
Russ Gorbybcd5abe2011-06-16 14:20:12 -070085#define MAX_MRU 1500
86#define MAX_MTU 1500
87#define GSM_NET_TX_TIMEOUT (HZ*10)
88
89/**
90 * struct gsm_mux_net - network interface
91 * @struct gsm_dlci* dlci
92 * @struct net_device_stats stats;
93 *
94 * Created when net interface is initialized.
95 **/
96struct gsm_mux_net {
97 struct kref ref;
98 struct gsm_dlci *dlci;
99 struct net_device_stats stats;
100};
101
102#define STATS(net) (((struct gsm_mux_net *)netdev_priv(net))->stats)
Alan Coxe1eaea42010-03-26 11:32:54 +0000103
104/*
105 * Each block of data we have queued to go out is in the form of
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300106 * a gsm_msg which holds everything we need in a link layer independent
Alan Coxe1eaea42010-03-26 11:32:54 +0000107 * format
108 */
109
110struct gsm_msg {
111 struct gsm_msg *next;
112 u8 addr; /* DLCI address + flags */
113 u8 ctrl; /* Control byte + flags */
114 unsigned int len; /* Length of data block (can be zero) */
115 unsigned char *data; /* Points into buffer but not at the start */
116 unsigned char buffer[0];
117};
118
119/*
120 * Each active data link has a gsm_dlci structure associated which ties
121 * the link layer to an optional tty (if the tty side is open). To avoid
122 * complexity right now these are only ever freed up when the mux is
123 * shut down.
124 *
125 * At the moment we don't free DLCI objects until the mux is torn down
126 * this avoid object life time issues but might be worth review later.
127 */
128
129struct gsm_dlci {
130 struct gsm_mux *gsm;
131 int addr;
132 int state;
133#define DLCI_CLOSED 0
134#define DLCI_OPENING 1 /* Sending SABM not seen UA */
135#define DLCI_OPEN 2 /* SABM/UA complete */
136#define DLCI_CLOSING 3 /* Sending DISC not seen UA/DM */
Russ Gorby6ab8fba2011-06-16 14:20:13 -0700137 struct kref ref; /* freed from port or mux close */
Russ Gorbybcd5abe2011-06-16 14:20:12 -0700138 struct mutex mutex;
Alan Coxe1eaea42010-03-26 11:32:54 +0000139
140 /* Link layer */
141 spinlock_t lock; /* Protects the internal state */
142 struct timer_list t1; /* Retransmit timer for SABM and UA */
143 int retries;
144 /* Uplink tty if active */
145 struct tty_port port; /* The tty bound to this DLCI if there is one */
146 struct kfifo *fifo; /* Queue fifo for the DLCI */
147 struct kfifo _fifo; /* For new fifo API porting only */
148 int adaption; /* Adaption layer in use */
Russ Gorbybcd5abe2011-06-16 14:20:12 -0700149 int prev_adaption;
Alan Coxe1eaea42010-03-26 11:32:54 +0000150 u32 modem_rx; /* Our incoming virtual modem lines */
151 u32 modem_tx; /* Our outgoing modem lines */
152 int dead; /* Refuse re-open */
153 /* Flow control */
154 int throttled; /* Private copy of throttle state */
155 int constipated; /* Throttle status for outgoing */
156 /* Packetised I/O */
157 struct sk_buff *skb; /* Frame being sent */
158 struct sk_buff_head skb_list; /* Queued frames */
159 /* Data handling callback */
160 void (*data)(struct gsm_dlci *dlci, u8 *data, int len);
Russ Gorbybcd5abe2011-06-16 14:20:12 -0700161 void (*prev_data)(struct gsm_dlci *dlci, u8 *data, int len);
162 struct net_device *net; /* network interface, if created */
Alan Coxe1eaea42010-03-26 11:32:54 +0000163};
164
165/* DLCI 0, 62/63 are special or reseved see gsmtty_open */
166
167#define NUM_DLCI 64
168
169/*
170 * DLCI 0 is used to pass control blocks out of band of the data
171 * flow (and with a higher link priority). One command can be outstanding
172 * at a time and we use this structure to manage them. They are created
173 * and destroyed by the user context, and updated by the receive paths
174 * and timers
175 */
176
177struct gsm_control {
178 u8 cmd; /* Command we are issuing */
179 u8 *data; /* Data for the command in case we retransmit */
180 int len; /* Length of block for retransmission */
181 int done; /* Done flag */
182 int error; /* Error if any */
183};
184
185/*
186 * Each GSM mux we have is represented by this structure. If we are
187 * operating as an ldisc then we use this structure as our ldisc
188 * state. We need to sort out lifetimes and locking with respect
189 * to the gsm mux array. For now we don't free DLCI objects that
190 * have been instantiated until the mux itself is terminated.
191 *
192 * To consider further: tty open versus mux shutdown.
193 */
194
195struct gsm_mux {
196 struct tty_struct *tty; /* The tty our ldisc is bound to */
197 spinlock_t lock;
Russ Gorbyd50f6dc2011-06-14 13:35:32 -0700198 unsigned int num;
Russ Gorby6ab8fba2011-06-16 14:20:13 -0700199 struct kref ref;
Alan Coxe1eaea42010-03-26 11:32:54 +0000200
201 /* Events on the GSM channel */
202 wait_queue_head_t event;
203
204 /* Bits for GSM mode decoding */
205
206 /* Framing Layer */
207 unsigned char *buf;
208 int state;
209#define GSM_SEARCH 0
210#define GSM_START 1
211#define GSM_ADDRESS 2
212#define GSM_CONTROL 3
213#define GSM_LEN 4
214#define GSM_DATA 5
215#define GSM_FCS 6
216#define GSM_OVERRUN 7
Alan Coxc2f2f002010-11-04 15:17:03 +0000217#define GSM_LEN0 8
218#define GSM_LEN1 9
219#define GSM_SSOF 10
Alan Coxe1eaea42010-03-26 11:32:54 +0000220 unsigned int len;
221 unsigned int address;
222 unsigned int count;
223 int escape;
224 int encoding;
225 u8 control;
226 u8 fcs;
Alan Coxc2f2f002010-11-04 15:17:03 +0000227 u8 received_fcs;
Alan Coxe1eaea42010-03-26 11:32:54 +0000228 u8 *txframe; /* TX framing buffer */
229
230 /* Methods for the receiver side */
231 void (*receive)(struct gsm_mux *gsm, u8 ch);
232 void (*error)(struct gsm_mux *gsm, u8 ch, u8 flag);
233 /* And transmit side */
234 int (*output)(struct gsm_mux *mux, u8 *data, int len);
235
236 /* Link Layer */
237 unsigned int mru;
238 unsigned int mtu;
239 int initiator; /* Did we initiate connection */
240 int dead; /* Has the mux been shut down */
241 struct gsm_dlci *dlci[NUM_DLCI];
242 int constipated; /* Asked by remote to shut up */
243
244 spinlock_t tx_lock;
245 unsigned int tx_bytes; /* TX data outstanding */
246#define TX_THRESH_HI 8192
247#define TX_THRESH_LO 2048
248 struct gsm_msg *tx_head; /* Pending data packets */
249 struct gsm_msg *tx_tail;
250
251 /* Control messages */
252 struct timer_list t2_timer; /* Retransmit timer for commands */
253 int cretries; /* Command retry counter */
254 struct gsm_control *pending_cmd;/* Our current pending command */
255 spinlock_t control_lock; /* Protects the pending command */
256
257 /* Configuration */
258 int adaption; /* 1 or 2 supported */
259 u8 ftype; /* UI or UIH */
260 int t1, t2; /* Timers in 1/100th of a sec */
261 int n2; /* Retry count */
262
263 /* Statistics (not currently exposed) */
264 unsigned long bad_fcs;
265 unsigned long malformed;
266 unsigned long io_error;
267 unsigned long bad_size;
268 unsigned long unsupported;
269};
270
271
272/*
273 * Mux objects - needed so that we can translate a tty index into the
274 * relevant mux and DLCI.
275 */
276
277#define MAX_MUX 4 /* 256 minors */
278static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */
279static spinlock_t gsm_mux_lock;
280
Russ Gorbyd50f6dc2011-06-14 13:35:32 -0700281static struct tty_driver *gsm_tty_driver;
282
Alan Coxe1eaea42010-03-26 11:32:54 +0000283/*
284 * This section of the driver logic implements the GSM encodings
285 * both the basic and the 'advanced'. Reliable transport is not
286 * supported.
287 */
288
289#define CR 0x02
290#define EA 0x01
291#define PF 0x10
292
293/* I is special: the rest are ..*/
294#define RR 0x01
295#define UI 0x03
296#define RNR 0x05
297#define REJ 0x09
298#define DM 0x0F
299#define SABM 0x2F
300#define DISC 0x43
301#define UA 0x63
302#define UIH 0xEF
303
304/* Channel commands */
305#define CMD_NSC 0x09
306#define CMD_TEST 0x11
307#define CMD_PSC 0x21
308#define CMD_RLS 0x29
309#define CMD_FCOFF 0x31
310#define CMD_PN 0x41
311#define CMD_RPN 0x49
312#define CMD_FCON 0x51
313#define CMD_CLD 0x61
314#define CMD_SNC 0x69
315#define CMD_MSC 0x71
316
317/* Virtual modem bits */
318#define MDM_FC 0x01
319#define MDM_RTC 0x02
320#define MDM_RTR 0x04
321#define MDM_IC 0x20
322#define MDM_DV 0x40
323
324#define GSM0_SOF 0xF9
Alan Cox5f9a31d2010-11-04 15:17:27 +0000325#define GSM1_SOF 0x7E
Alan Coxe1eaea42010-03-26 11:32:54 +0000326#define GSM1_ESCAPE 0x7D
327#define GSM1_ESCAPE_BITS 0x20
328#define XON 0x11
329#define XOFF 0x13
330
331static const struct tty_port_operations gsm_port_ops;
332
333/*
334 * CRC table for GSM 0710
335 */
336
337static const u8 gsm_fcs8[256] = {
338 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75,
339 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B,
340 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69,
341 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67,
342 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D,
343 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43,
344 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51,
345 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F,
346 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05,
347 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B,
348 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19,
349 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17,
350 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D,
351 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33,
352 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21,
353 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F,
354 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95,
355 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B,
356 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89,
357 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87,
358 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD,
359 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3,
360 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1,
361 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF,
362 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5,
363 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB,
364 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9,
365 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7,
366 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD,
367 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3,
368 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1,
369 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF
370};
371
372#define INIT_FCS 0xFF
373#define GOOD_FCS 0xCF
374
375/**
376 * gsm_fcs_add - update FCS
377 * @fcs: Current FCS
378 * @c: Next data
379 *
380 * Update the FCS to include c. Uses the algorithm in the specification
381 * notes.
382 */
383
384static inline u8 gsm_fcs_add(u8 fcs, u8 c)
385{
386 return gsm_fcs8[fcs ^ c];
387}
388
389/**
390 * gsm_fcs_add_block - update FCS for a block
391 * @fcs: Current FCS
392 * @c: buffer of data
393 * @len: length of buffer
394 *
395 * Update the FCS to include c. Uses the algorithm in the specification
396 * notes.
397 */
398
399static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len)
400{
401 while (len--)
402 fcs = gsm_fcs8[fcs ^ *c++];
403 return fcs;
404}
405
406/**
407 * gsm_read_ea - read a byte into an EA
408 * @val: variable holding value
409 * c: byte going into the EA
410 *
411 * Processes one byte of an EA. Updates the passed variable
412 * and returns 1 if the EA is now completely read
413 */
414
415static int gsm_read_ea(unsigned int *val, u8 c)
416{
417 /* Add the next 7 bits into the value */
418 *val <<= 7;
419 *val |= c >> 1;
420 /* Was this the last byte of the EA 1 = yes*/
421 return c & EA;
422}
423
424/**
425 * gsm_encode_modem - encode modem data bits
426 * @dlci: DLCI to encode from
427 *
428 * Returns the correct GSM encoded modem status bits (6 bit field) for
429 * the current status of the DLCI and attached tty object
430 */
431
432static u8 gsm_encode_modem(const struct gsm_dlci *dlci)
433{
434 u8 modembits = 0;
435 /* FC is true flow control not modem bits */
436 if (dlci->throttled)
437 modembits |= MDM_FC;
438 if (dlci->modem_tx & TIOCM_DTR)
439 modembits |= MDM_RTC;
440 if (dlci->modem_tx & TIOCM_RTS)
441 modembits |= MDM_RTR;
442 if (dlci->modem_tx & TIOCM_RI)
443 modembits |= MDM_IC;
444 if (dlci->modem_tx & TIOCM_CD)
445 modembits |= MDM_DV;
446 return modembits;
447}
448
449/**
450 * gsm_print_packet - display a frame for debug
451 * @hdr: header to print before decode
452 * @addr: address EA from the frame
453 * @cr: C/R bit from the frame
454 * @control: control including PF bit
455 * @data: following data bytes
456 * @dlen: length of data
457 *
458 * Displays a packet in human readable format for debugging purposes. The
459 * style is based on amateur radio LAP-B dump display.
460 */
461
462static void gsm_print_packet(const char *hdr, int addr, int cr,
463 u8 control, const u8 *data, int dlen)
464{
465 if (!(debug & 1))
466 return;
467
Alan Cox5f9a31d2010-11-04 15:17:27 +0000468 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]);
Alan Coxe1eaea42010-03-26 11:32:54 +0000469
470 switch (control & ~PF) {
471 case SABM:
Alan Cox5f9a31d2010-11-04 15:17:27 +0000472 pr_cont("SABM");
Alan Coxe1eaea42010-03-26 11:32:54 +0000473 break;
474 case UA:
Alan Cox5f9a31d2010-11-04 15:17:27 +0000475 pr_cont("UA");
Alan Coxe1eaea42010-03-26 11:32:54 +0000476 break;
477 case DISC:
Alan Cox5f9a31d2010-11-04 15:17:27 +0000478 pr_cont("DISC");
Alan Coxe1eaea42010-03-26 11:32:54 +0000479 break;
480 case DM:
Alan Cox5f9a31d2010-11-04 15:17:27 +0000481 pr_cont("DM");
Alan Coxe1eaea42010-03-26 11:32:54 +0000482 break;
483 case UI:
Alan Cox5f9a31d2010-11-04 15:17:27 +0000484 pr_cont("UI");
Alan Coxe1eaea42010-03-26 11:32:54 +0000485 break;
486 case UIH:
Alan Cox5f9a31d2010-11-04 15:17:27 +0000487 pr_cont("UIH");
Alan Coxe1eaea42010-03-26 11:32:54 +0000488 break;
489 default:
490 if (!(control & 0x01)) {
Alan Cox5f9a31d2010-11-04 15:17:27 +0000491 pr_cont("I N(S)%d N(R)%d",
492 (control & 0x0E) >> 1, (control & 0xE) >> 5);
Alan Coxe1eaea42010-03-26 11:32:54 +0000493 } else switch (control & 0x0F) {
Alan Cox5f9a31d2010-11-04 15:17:27 +0000494 case RR:
495 pr_cont("RR(%d)", (control & 0xE0) >> 5);
496 break;
497 case RNR:
498 pr_cont("RNR(%d)", (control & 0xE0) >> 5);
499 break;
500 case REJ:
501 pr_cont("REJ(%d)", (control & 0xE0) >> 5);
502 break;
503 default:
504 pr_cont("[%02X]", control);
Alan Coxe1eaea42010-03-26 11:32:54 +0000505 }
506 }
507
508 if (control & PF)
Alan Cox5f9a31d2010-11-04 15:17:27 +0000509 pr_cont("(P)");
Alan Coxe1eaea42010-03-26 11:32:54 +0000510 else
Alan Cox5f9a31d2010-11-04 15:17:27 +0000511 pr_cont("(F)");
Alan Coxe1eaea42010-03-26 11:32:54 +0000512
513 if (dlen) {
514 int ct = 0;
515 while (dlen--) {
Alan Cox5f9a31d2010-11-04 15:17:27 +0000516 if (ct % 8 == 0) {
517 pr_cont("\n");
518 pr_debug(" ");
519 }
520 pr_cont("%02X ", *data++);
Alan Coxe1eaea42010-03-26 11:32:54 +0000521 ct++;
522 }
523 }
Alan Cox5f9a31d2010-11-04 15:17:27 +0000524 pr_cont("\n");
Alan Coxe1eaea42010-03-26 11:32:54 +0000525}
526
527
528/*
529 * Link level transmission side
530 */
531
532/**
533 * gsm_stuff_packet - bytestuff a packet
534 * @ibuf: input
535 * @obuf: output
536 * @len: length of input
537 *
538 * Expand a buffer by bytestuffing it. The worst case size change
539 * is doubling and the caller is responsible for handing out
540 * suitable sized buffers.
541 */
542
543static int gsm_stuff_frame(const u8 *input, u8 *output, int len)
544{
545 int olen = 0;
546 while (len--) {
547 if (*input == GSM1_SOF || *input == GSM1_ESCAPE
548 || *input == XON || *input == XOFF) {
549 *output++ = GSM1_ESCAPE;
550 *output++ = *input++ ^ GSM1_ESCAPE_BITS;
551 olen++;
552 } else
553 *output++ = *input++;
554 olen++;
555 }
556 return olen;
557}
558
Alan Coxe1eaea42010-03-26 11:32:54 +0000559/**
560 * gsm_send - send a control frame
561 * @gsm: our GSM mux
562 * @addr: address for control frame
563 * @cr: command/response bit
564 * @control: control byte including PF bit
565 *
566 * Format up and transmit a control frame. These do not go via the
567 * queueing logic as they should be transmitted ahead of data when
568 * they are needed.
569 *
570 * FIXME: Lock versus data TX path
571 */
572
573static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control)
574{
575 int len;
576 u8 cbuf[10];
577 u8 ibuf[3];
578
579 switch (gsm->encoding) {
580 case 0:
581 cbuf[0] = GSM0_SOF;
582 cbuf[1] = (addr << 2) | (cr << 1) | EA;
583 cbuf[2] = control;
584 cbuf[3] = EA; /* Length of data = 0 */
585 cbuf[4] = 0xFF - gsm_fcs_add_block(INIT_FCS, cbuf + 1, 3);
586 cbuf[5] = GSM0_SOF;
587 len = 6;
588 break;
589 case 1:
590 case 2:
591 /* Control frame + packing (but not frame stuffing) in mode 1 */
592 ibuf[0] = (addr << 2) | (cr << 1) | EA;
593 ibuf[1] = control;
594 ibuf[2] = 0xFF - gsm_fcs_add_block(INIT_FCS, ibuf, 2);
595 /* Stuffing may double the size worst case */
596 len = gsm_stuff_frame(ibuf, cbuf + 1, 3);
597 /* Now add the SOF markers */
598 cbuf[0] = GSM1_SOF;
599 cbuf[len + 1] = GSM1_SOF;
600 /* FIXME: we can omit the lead one in many cases */
601 len += 2;
602 break;
603 default:
604 WARN_ON(1);
605 return;
606 }
607 gsm->output(gsm, cbuf, len);
608 gsm_print_packet("-->", addr, cr, control, NULL, 0);
609}
610
611/**
612 * gsm_response - send a control response
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 response frame.
618 */
619
620static inline void gsm_response(struct gsm_mux *gsm, int addr, int control)
621{
622 gsm_send(gsm, addr, 0, control);
623}
624
625/**
626 * gsm_command - send a control command
627 * @gsm: our GSM mux
628 * @addr: address for control frame
629 * @control: control byte including PF bit
630 *
631 * Format up and transmit a link level command frame.
632 */
633
634static inline void gsm_command(struct gsm_mux *gsm, int addr, int control)
635{
636 gsm_send(gsm, addr, 1, control);
637}
638
639/* Data transmission */
640
641#define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */
642
643/**
644 * gsm_data_alloc - allocate data frame
645 * @gsm: GSM mux
646 * @addr: DLCI address
647 * @len: length excluding header and FCS
648 * @ctrl: control byte
649 *
650 * Allocate a new data buffer for sending frames with data. Space is left
651 * at the front for header bytes but that is treated as an implementation
652 * detail and not for the high level code to use
653 */
654
655static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
656 u8 ctrl)
657{
658 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN,
659 GFP_ATOMIC);
660 if (m == NULL)
661 return NULL;
662 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */
663 m->len = len;
664 m->addr = addr;
665 m->ctrl = ctrl;
666 m->next = NULL;
667 return m;
668}
669
670/**
671 * gsm_data_kick - poke the queue
672 * @gsm: GSM Mux
673 *
674 * The tty device has called us to indicate that room has appeared in
675 * the transmit queue. Ram more data into the pipe if we have any
676 *
677 * FIXME: lock against link layer control transmissions
678 */
679
680static void gsm_data_kick(struct gsm_mux *gsm)
681{
682 struct gsm_msg *msg = gsm->tx_head;
683 int len;
684 int skip_sof = 0;
685
686 /* FIXME: We need to apply this solely to data messages */
687 if (gsm->constipated)
688 return;
689
690 while (gsm->tx_head != NULL) {
691 msg = gsm->tx_head;
692 if (gsm->encoding != 0) {
693 gsm->txframe[0] = GSM1_SOF;
694 len = gsm_stuff_frame(msg->data,
695 gsm->txframe + 1, msg->len);
696 gsm->txframe[len + 1] = GSM1_SOF;
697 len += 2;
698 } else {
699 gsm->txframe[0] = GSM0_SOF;
700 memcpy(gsm->txframe + 1 , msg->data, msg->len);
701 gsm->txframe[msg->len + 1] = GSM0_SOF;
702 len = msg->len + 2;
703 }
704
Joe Perches0a77c4f2011-04-25 16:46:49 -0700705 if (debug & 4)
706 print_hex_dump_bytes("gsm_data_kick: ",
707 DUMP_PREFIX_OFFSET,
708 gsm->txframe, len);
Alan Coxe1eaea42010-03-26 11:32:54 +0000709
710 if (gsm->output(gsm, gsm->txframe + skip_sof,
711 len - skip_sof) < 0)
712 break;
713 /* FIXME: Can eliminate one SOF in many more cases */
714 gsm->tx_head = msg->next;
715 if (gsm->tx_head == NULL)
716 gsm->tx_tail = NULL;
717 gsm->tx_bytes -= msg->len;
718 kfree(msg);
719 /* For a burst of frames skip the extra SOF within the
720 burst */
721 skip_sof = 1;
722 }
723}
724
725/**
726 * __gsm_data_queue - queue a UI or UIH frame
727 * @dlci: DLCI sending the data
728 * @msg: message queued
729 *
730 * Add data to the transmit queue and try and get stuff moving
731 * out of the mux tty if not already doing so. The Caller must hold
732 * the gsm tx lock.
733 */
734
735static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
736{
737 struct gsm_mux *gsm = dlci->gsm;
738 u8 *dp = msg->data;
739 u8 *fcs = dp + msg->len;
740
741 /* Fill in the header */
742 if (gsm->encoding == 0) {
743 if (msg->len < 128)
744 *--dp = (msg->len << 1) | EA;
745 else {
Ken Millsbe7a7412010-12-13 15:27:27 +0000746 *--dp = (msg->len >> 7); /* bits 7 - 15 */
747 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */
Alan Coxe1eaea42010-03-26 11:32:54 +0000748 }
749 }
750
751 *--dp = msg->ctrl;
752 if (gsm->initiator)
753 *--dp = (msg->addr << 2) | 2 | EA;
754 else
755 *--dp = (msg->addr << 2) | EA;
756 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp);
757 /* Ugly protocol layering violation */
758 if (msg->ctrl == UI || msg->ctrl == (UI|PF))
759 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len);
760 *fcs = 0xFF - *fcs;
761
762 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl,
763 msg->data, msg->len);
764
765 /* Move the header back and adjust the length, also allow for the FCS
766 now tacked on the end */
767 msg->len += (msg->data - dp) + 1;
768 msg->data = dp;
769
770 /* Add to the actual output queue */
771 if (gsm->tx_tail)
772 gsm->tx_tail->next = msg;
773 else
774 gsm->tx_head = msg;
775 gsm->tx_tail = msg;
776 gsm->tx_bytes += msg->len;
777 gsm_data_kick(gsm);
778}
779
780/**
781 * gsm_data_queue - queue a UI or UIH frame
782 * @dlci: DLCI sending the data
783 * @msg: message queued
784 *
785 * Add data to the transmit queue and try and get stuff moving
786 * out of the mux tty if not already doing so. Take the
787 * the gsm tx lock and dlci lock.
788 */
789
790static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
791{
792 unsigned long flags;
793 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
794 __gsm_data_queue(dlci, msg);
795 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
796}
797
798/**
799 * gsm_dlci_data_output - try and push data out of a DLCI
800 * @gsm: mux
801 * @dlci: the DLCI to pull data from
802 *
803 * Pull data from a DLCI and send it into the transmit queue if there
804 * is data. Keep to the MRU of the mux. This path handles the usual tty
805 * interface which is a byte stream with optional modem data.
806 *
807 * Caller must hold the tx_lock of the mux.
808 */
809
810static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci)
811{
812 struct gsm_msg *msg;
813 u8 *dp;
Mikhail Kshevetskiy268e5262011-09-23 19:22:56 +0400814 int len, total_size, size;
Alan Coxe1eaea42010-03-26 11:32:54 +0000815 int h = dlci->adaption - 1;
816
Mikhail Kshevetskiy268e5262011-09-23 19:22:56 +0400817 total_size = 0;
818 while(1) {
819 len = kfifo_len(dlci->fifo);
820 if (len == 0)
821 return total_size;
Alan Coxe1eaea42010-03-26 11:32:54 +0000822
Mikhail Kshevetskiy268e5262011-09-23 19:22:56 +0400823 /* MTU/MRU count only the data bits */
824 if (len > gsm->mtu)
825 len = gsm->mtu;
Alan Coxe1eaea42010-03-26 11:32:54 +0000826
Mikhail Kshevetskiy268e5262011-09-23 19:22:56 +0400827 size = len + h;
Alan Coxe1eaea42010-03-26 11:32:54 +0000828
Mikhail Kshevetskiy268e5262011-09-23 19:22:56 +0400829 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
830 /* FIXME: need a timer or something to kick this so it can't
831 get stuck with no work outstanding and no buffer free */
832 if (msg == NULL)
833 return -ENOMEM;
834 dp = msg->data;
835 switch (dlci->adaption) {
836 case 1: /* Unstructured */
837 break;
838 case 2: /* Unstructed with modem bits. Always one byte as we never
839 send inline break data */
840 *dp++ = gsm_encode_modem(dlci);
841 break;
842 }
843 WARN_ON(kfifo_out_locked(dlci->fifo, dp , len, &dlci->lock) != len);
844 __gsm_data_queue(dlci, msg);
845 total_size += size;
Alan Coxe1eaea42010-03-26 11:32:54 +0000846 }
Alan Coxe1eaea42010-03-26 11:32:54 +0000847 /* Bytes of data we used up */
Mikhail Kshevetskiy268e5262011-09-23 19:22:56 +0400848 return total_size;
Alan Coxe1eaea42010-03-26 11:32:54 +0000849}
850
851/**
852 * gsm_dlci_data_output_framed - try and push data out of a DLCI
853 * @gsm: mux
854 * @dlci: the DLCI to pull data from
855 *
856 * Pull data from a DLCI and send it into the transmit queue if there
857 * is data. Keep to the MRU of the mux. This path handles framed data
858 * queued as skbuffs to the DLCI.
859 *
860 * Caller must hold the tx_lock of the mux.
861 */
862
863static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
864 struct gsm_dlci *dlci)
865{
866 struct gsm_msg *msg;
867 u8 *dp;
868 int len, size;
869 int last = 0, first = 0;
870 int overhead = 0;
871
872 /* One byte per frame is used for B/F flags */
873 if (dlci->adaption == 4)
874 overhead = 1;
875
876 /* dlci->skb is locked by tx_lock */
877 if (dlci->skb == NULL) {
878 dlci->skb = skb_dequeue(&dlci->skb_list);
879 if (dlci->skb == NULL)
880 return 0;
881 first = 1;
882 }
883 len = dlci->skb->len + overhead;
884
885 /* MTU/MRU count only the data bits */
886 if (len > gsm->mtu) {
887 if (dlci->adaption == 3) {
888 /* Over long frame, bin it */
889 kfree_skb(dlci->skb);
890 dlci->skb = NULL;
891 return 0;
892 }
893 len = gsm->mtu;
894 } else
895 last = 1;
896
897 size = len + overhead;
898 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
899
900 /* FIXME: need a timer or something to kick this so it can't
901 get stuck with no work outstanding and no buffer free */
902 if (msg == NULL)
903 return -ENOMEM;
904 dp = msg->data;
905
906 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */
907 /* Flag byte to carry the start/end info */
908 *dp++ = last << 7 | first << 6 | 1; /* EA */
909 len--;
910 }
Russ Gorby57f21042011-06-14 13:23:29 -0700911 memcpy(dp, dlci->skb->data, len);
912 skb_pull(dlci->skb, len);
Alan Coxe1eaea42010-03-26 11:32:54 +0000913 __gsm_data_queue(dlci, msg);
Russ Gorbybcd5abe2011-06-16 14:20:12 -0700914 if (last) {
915 kfree_skb(dlci->skb);
Alan Coxe1eaea42010-03-26 11:32:54 +0000916 dlci->skb = NULL;
Russ Gorbybcd5abe2011-06-16 14:20:12 -0700917 }
Alan Coxe1eaea42010-03-26 11:32:54 +0000918 return size;
919}
920
921/**
922 * gsm_dlci_data_sweep - look for data to send
923 * @gsm: the GSM mux
924 *
925 * Sweep the GSM mux channels in priority order looking for ones with
926 * data to send. We could do with optimising this scan a bit. We aim
927 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit
928 * TX_THRESH_LO we get called again
929 *
930 * FIXME: We should round robin between groups and in theory you can
931 * renegotiate DLCI priorities with optional stuff. Needs optimising.
932 */
933
934static void gsm_dlci_data_sweep(struct gsm_mux *gsm)
935{
936 int len;
937 /* Priority ordering: We should do priority with RR of the groups */
938 int i = 1;
Alan Coxe1eaea42010-03-26 11:32:54 +0000939
Alan Coxe1eaea42010-03-26 11:32:54 +0000940 while (i < NUM_DLCI) {
941 struct gsm_dlci *dlci;
942
943 if (gsm->tx_bytes > TX_THRESH_HI)
944 break;
945 dlci = gsm->dlci[i];
946 if (dlci == NULL || dlci->constipated) {
947 i++;
948 continue;
949 }
Russ Gorbybcd5abe2011-06-16 14:20:12 -0700950 if (dlci->adaption < 3 && !dlci->net)
Alan Coxe1eaea42010-03-26 11:32:54 +0000951 len = gsm_dlci_data_output(gsm, dlci);
952 else
953 len = gsm_dlci_data_output_framed(gsm, dlci);
954 if (len < 0)
Julia Lawalle73790a2010-08-10 18:03:12 -0700955 break;
Alan Coxe1eaea42010-03-26 11:32:54 +0000956 /* DLCI empty - try the next */
957 if (len == 0)
958 i++;
959 }
Alan Coxe1eaea42010-03-26 11:32:54 +0000960}
961
962/**
963 * gsm_dlci_data_kick - transmit if possible
964 * @dlci: DLCI to kick
965 *
966 * Transmit data from this DLCI if the queue is empty. We can't rely on
967 * a tty wakeup except when we filled the pipe so we need to fire off
968 * new data ourselves in other cases.
969 */
970
971static void gsm_dlci_data_kick(struct gsm_dlci *dlci)
972{
973 unsigned long flags;
974
975 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
976 /* If we have nothing running then we need to fire up */
Russ Gorbybcd5abe2011-06-16 14:20:12 -0700977 if (dlci->gsm->tx_bytes == 0) {
978 if (dlci->net)
979 gsm_dlci_data_output_framed(dlci->gsm, dlci);
980 else
981 gsm_dlci_data_output(dlci->gsm, dlci);
982 } else if (dlci->gsm->tx_bytes < TX_THRESH_LO)
Alan Coxe1eaea42010-03-26 11:32:54 +0000983 gsm_dlci_data_sweep(dlci->gsm);
984 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
985}
986
987/*
988 * Control message processing
989 */
990
991
992/**
993 * gsm_control_reply - send a response frame to a control
994 * @gsm: gsm channel
995 * @cmd: the command to use
996 * @data: data to follow encoded info
997 * @dlen: length of data
998 *
999 * Encode up and queue a UI/UIH frame containing our response.
1000 */
1001
1002static void gsm_control_reply(struct gsm_mux *gsm, int cmd, u8 *data,
1003 int dlen)
1004{
1005 struct gsm_msg *msg;
1006 msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype);
Ken Mills093d8042010-12-13 15:28:03 +00001007 if (msg == NULL)
1008 return;
Alan Coxe1eaea42010-03-26 11:32:54 +00001009 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */
1010 msg->data[1] = (dlen << 1) | EA;
1011 memcpy(msg->data + 2, data, dlen);
1012 gsm_data_queue(gsm->dlci[0], msg);
1013}
1014
1015/**
1016 * gsm_process_modem - process received modem status
1017 * @tty: virtual tty bound to the DLCI
1018 * @dlci: DLCI to affect
1019 * @modem: modem bits (full EA)
1020 *
1021 * Used when a modem control message or line state inline in adaption
1022 * layer 2 is processed. Sort out the local modem state and throttles
1023 */
1024
1025static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
Russ Gorby72632872011-06-14 13:23:28 -07001026 u32 modem, int clen)
Alan Coxe1eaea42010-03-26 11:32:54 +00001027{
1028 int mlines = 0;
Russ Gorby72632872011-06-14 13:23:28 -07001029 u8 brk = 0;
1030
1031 /* The modem status command can either contain one octet (v.24 signals)
1032 or two octets (v.24 signals + break signals). The length field will
1033 either be 2 or 3 respectively. This is specified in section
1034 5.4.6.3.7 of the 27.010 mux spec. */
1035
1036 if (clen == 2)
1037 modem = modem & 0x7f;
1038 else {
1039 brk = modem & 0x7f;
1040 modem = (modem >> 7) & 0x7f;
1041 };
Alan Coxe1eaea42010-03-26 11:32:54 +00001042
1043 /* Flow control/ready to communicate */
1044 if (modem & MDM_FC) {
1045 /* Need to throttle our output on this device */
1046 dlci->constipated = 1;
1047 }
1048 if (modem & MDM_RTC) {
1049 mlines |= TIOCM_DSR | TIOCM_DTR;
1050 dlci->constipated = 0;
1051 gsm_dlci_data_kick(dlci);
1052 }
1053 /* Map modem bits */
1054 if (modem & MDM_RTR)
1055 mlines |= TIOCM_RTS | TIOCM_CTS;
1056 if (modem & MDM_IC)
1057 mlines |= TIOCM_RI;
1058 if (modem & MDM_DV)
1059 mlines |= TIOCM_CD;
1060
1061 /* Carrier drop -> hangup */
1062 if (tty) {
1063 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD))
1064 if (!(tty->termios->c_cflag & CLOCAL))
1065 tty_hangup(tty);
1066 if (brk & 0x01)
1067 tty_insert_flip_char(tty, 0, TTY_BREAK);
1068 }
1069 dlci->modem_rx = mlines;
1070}
1071
1072/**
1073 * gsm_control_modem - modem status received
1074 * @gsm: GSM channel
1075 * @data: data following command
1076 * @clen: command length
1077 *
1078 * We have received a modem status control message. This is used by
1079 * the GSM mux protocol to pass virtual modem line status and optionally
1080 * to indicate break signals. Unpack it, convert to Linux representation
1081 * and if need be stuff a break message down the tty.
1082 */
1083
1084static void gsm_control_modem(struct gsm_mux *gsm, u8 *data, int clen)
1085{
1086 unsigned int addr = 0;
1087 unsigned int modem = 0;
1088 struct gsm_dlci *dlci;
1089 int len = clen;
1090 u8 *dp = data;
1091 struct tty_struct *tty;
1092
1093 while (gsm_read_ea(&addr, *dp++) == 0) {
1094 len--;
1095 if (len == 0)
1096 return;
1097 }
1098 /* Must be at least one byte following the EA */
1099 len--;
1100 if (len <= 0)
1101 return;
1102
1103 addr >>= 1;
1104 /* Closed port, or invalid ? */
1105 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1106 return;
1107 dlci = gsm->dlci[addr];
1108
1109 while (gsm_read_ea(&modem, *dp++) == 0) {
1110 len--;
1111 if (len == 0)
1112 return;
1113 }
1114 tty = tty_port_tty_get(&dlci->port);
Russ Gorby72632872011-06-14 13:23:28 -07001115 gsm_process_modem(tty, dlci, modem, clen);
Alan Coxe1eaea42010-03-26 11:32:54 +00001116 if (tty) {
1117 tty_wakeup(tty);
1118 tty_kref_put(tty);
1119 }
1120 gsm_control_reply(gsm, CMD_MSC, data, clen);
1121}
1122
1123/**
1124 * gsm_control_rls - remote line status
1125 * @gsm: GSM channel
1126 * @data: data bytes
1127 * @clen: data length
1128 *
1129 * The modem sends us a two byte message on the control channel whenever
1130 * it wishes to send us an error state from the virtual link. Stuff
1131 * this into the uplink tty if present
1132 */
1133
1134static void gsm_control_rls(struct gsm_mux *gsm, u8 *data, int clen)
1135{
1136 struct tty_struct *tty;
1137 unsigned int addr = 0 ;
1138 u8 bits;
1139 int len = clen;
1140 u8 *dp = data;
1141
1142 while (gsm_read_ea(&addr, *dp++) == 0) {
1143 len--;
1144 if (len == 0)
1145 return;
1146 }
1147 /* Must be at least one byte following ea */
1148 len--;
1149 if (len <= 0)
1150 return;
1151 addr >>= 1;
1152 /* Closed port, or invalid ? */
1153 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1154 return;
1155 /* No error ? */
1156 bits = *dp;
1157 if ((bits & 1) == 0)
1158 return;
1159 /* See if we have an uplink tty */
1160 tty = tty_port_tty_get(&gsm->dlci[addr]->port);
1161
1162 if (tty) {
1163 if (bits & 2)
1164 tty_insert_flip_char(tty, 0, TTY_OVERRUN);
1165 if (bits & 4)
1166 tty_insert_flip_char(tty, 0, TTY_PARITY);
1167 if (bits & 8)
1168 tty_insert_flip_char(tty, 0, TTY_FRAME);
1169 tty_flip_buffer_push(tty);
1170 tty_kref_put(tty);
1171 }
1172 gsm_control_reply(gsm, CMD_RLS, data, clen);
1173}
1174
1175static void gsm_dlci_begin_close(struct gsm_dlci *dlci);
1176
1177/**
1178 * gsm_control_message - DLCI 0 control processing
1179 * @gsm: our GSM mux
1180 * @command: the command EA
1181 * @data: data beyond the command/length EAs
1182 * @clen: length
1183 *
1184 * Input processor for control messages from the other end of the link.
1185 * Processes the incoming request and queues a response frame or an
1186 * NSC response if not supported
1187 */
1188
1189static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
1190 u8 *data, int clen)
1191{
1192 u8 buf[1];
1193 switch (command) {
1194 case CMD_CLD: {
1195 struct gsm_dlci *dlci = gsm->dlci[0];
1196 /* Modem wishes to close down */
1197 if (dlci) {
1198 dlci->dead = 1;
1199 gsm->dead = 1;
1200 gsm_dlci_begin_close(dlci);
1201 }
1202 }
1203 break;
1204 case CMD_TEST:
1205 /* Modem wishes to test, reply with the data */
1206 gsm_control_reply(gsm, CMD_TEST, data, clen);
1207 break;
1208 case CMD_FCON:
1209 /* Modem wants us to STFU */
1210 gsm->constipated = 1;
1211 gsm_control_reply(gsm, CMD_FCON, NULL, 0);
1212 break;
1213 case CMD_FCOFF:
1214 /* Modem can accept data again */
1215 gsm->constipated = 0;
1216 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0);
1217 /* Kick the link in case it is idling */
1218 gsm_data_kick(gsm);
1219 break;
1220 case CMD_MSC:
1221 /* Out of band modem line change indicator for a DLCI */
1222 gsm_control_modem(gsm, data, clen);
1223 break;
1224 case CMD_RLS:
1225 /* Out of band error reception for a DLCI */
1226 gsm_control_rls(gsm, data, clen);
1227 break;
1228 case CMD_PSC:
1229 /* Modem wishes to enter power saving state */
1230 gsm_control_reply(gsm, CMD_PSC, NULL, 0);
1231 break;
1232 /* Optional unsupported commands */
1233 case CMD_PN: /* Parameter negotiation */
Lucas De Marchi25985ed2011-03-30 22:57:33 -03001234 case CMD_RPN: /* Remote port negotiation */
1235 case CMD_SNC: /* Service negotiation command */
Alan Coxe1eaea42010-03-26 11:32:54 +00001236 default:
1237 /* Reply to bad commands with an NSC */
1238 buf[0] = command;
1239 gsm_control_reply(gsm, CMD_NSC, buf, 1);
1240 break;
1241 }
1242}
1243
1244/**
1245 * gsm_control_response - process a response to our control
1246 * @gsm: our GSM mux
1247 * @command: the command (response) EA
1248 * @data: data beyond the command/length EA
1249 * @clen: length
1250 *
1251 * Process a response to an outstanding command. We only allow a single
1252 * control message in flight so this is fairly easy. All the clean up
1253 * is done by the caller, we just update the fields, flag it as done
1254 * and return
1255 */
1256
1257static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
1258 u8 *data, int clen)
1259{
1260 struct gsm_control *ctrl;
1261 unsigned long flags;
1262
1263 spin_lock_irqsave(&gsm->control_lock, flags);
1264
1265 ctrl = gsm->pending_cmd;
1266 /* Does the reply match our command */
1267 command |= 1;
1268 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) {
1269 /* Our command was replied to, kill the retry timer */
1270 del_timer(&gsm->t2_timer);
1271 gsm->pending_cmd = NULL;
1272 /* Rejected by the other end */
1273 if (command == CMD_NSC)
1274 ctrl->error = -EOPNOTSUPP;
1275 ctrl->done = 1;
1276 wake_up(&gsm->event);
1277 }
1278 spin_unlock_irqrestore(&gsm->control_lock, flags);
1279}
1280
1281/**
Alan Cox5f9a31d2010-11-04 15:17:27 +00001282 * gsm_control_transmit - send control packet
Alan Coxe1eaea42010-03-26 11:32:54 +00001283 * @gsm: gsm mux
1284 * @ctrl: frame to send
1285 *
1286 * Send out a pending control command (called under control lock)
1287 */
1288
1289static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl)
1290{
Eric Bénarded43b472011-03-09 19:24:49 +01001291 struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, gsm->ftype);
Alan Coxe1eaea42010-03-26 11:32:54 +00001292 if (msg == NULL)
1293 return;
1294 msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */
1295 memcpy(msg->data + 1, ctrl->data, ctrl->len);
1296 gsm_data_queue(gsm->dlci[0], msg);
1297}
1298
1299/**
1300 * gsm_control_retransmit - retransmit a control frame
1301 * @data: pointer to our gsm object
1302 *
1303 * Called off the T2 timer expiry in order to retransmit control frames
1304 * that have been lost in the system somewhere. The control_lock protects
1305 * us from colliding with another sender or a receive completion event.
1306 * In that situation the timer may still occur in a small window but
1307 * gsm->pending_cmd will be NULL and we just let the timer expire.
1308 */
1309
1310static void gsm_control_retransmit(unsigned long data)
1311{
1312 struct gsm_mux *gsm = (struct gsm_mux *)data;
1313 struct gsm_control *ctrl;
1314 unsigned long flags;
1315 spin_lock_irqsave(&gsm->control_lock, flags);
1316 ctrl = gsm->pending_cmd;
1317 if (ctrl) {
1318 gsm->cretries--;
1319 if (gsm->cretries == 0) {
1320 gsm->pending_cmd = NULL;
1321 ctrl->error = -ETIMEDOUT;
1322 ctrl->done = 1;
1323 spin_unlock_irqrestore(&gsm->control_lock, flags);
1324 wake_up(&gsm->event);
1325 return;
1326 }
1327 gsm_control_transmit(gsm, ctrl);
1328 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1329 }
1330 spin_unlock_irqrestore(&gsm->control_lock, flags);
1331}
1332
1333/**
1334 * gsm_control_send - send a control frame on DLCI 0
1335 * @gsm: the GSM channel
1336 * @command: command to send including CR bit
1337 * @data: bytes of data (must be kmalloced)
1338 * @len: length of the block to send
1339 *
1340 * Queue and dispatch a control command. Only one command can be
1341 * active at a time. In theory more can be outstanding but the matching
1342 * gets really complicated so for now stick to one outstanding.
1343 */
1344
1345static struct gsm_control *gsm_control_send(struct gsm_mux *gsm,
1346 unsigned int command, u8 *data, int clen)
1347{
1348 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control),
1349 GFP_KERNEL);
1350 unsigned long flags;
1351 if (ctrl == NULL)
1352 return NULL;
1353retry:
1354 wait_event(gsm->event, gsm->pending_cmd == NULL);
1355 spin_lock_irqsave(&gsm->control_lock, flags);
1356 if (gsm->pending_cmd != NULL) {
1357 spin_unlock_irqrestore(&gsm->control_lock, flags);
1358 goto retry;
1359 }
1360 ctrl->cmd = command;
1361 ctrl->data = data;
1362 ctrl->len = clen;
1363 gsm->pending_cmd = ctrl;
1364 gsm->cretries = gsm->n2;
1365 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1366 gsm_control_transmit(gsm, ctrl);
1367 spin_unlock_irqrestore(&gsm->control_lock, flags);
1368 return ctrl;
1369}
1370
1371/**
1372 * gsm_control_wait - wait for a control to finish
1373 * @gsm: GSM mux
1374 * @control: control we are waiting on
1375 *
1376 * Waits for the control to complete or time out. Frees any used
1377 * resources and returns 0 for success, or an error if the remote
1378 * rejected or ignored the request.
1379 */
1380
1381static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
1382{
1383 int err;
1384 wait_event(gsm->event, control->done == 1);
1385 err = control->error;
1386 kfree(control);
1387 return err;
1388}
1389
1390
1391/*
1392 * DLCI level handling: Needs krefs
1393 */
1394
1395/*
1396 * State transitions and timers
1397 */
1398
1399/**
1400 * gsm_dlci_close - a DLCI has closed
1401 * @dlci: DLCI that closed
1402 *
1403 * Perform processing when moving a DLCI into closed state. If there
1404 * is an attached tty this is hung up
1405 */
1406
1407static void gsm_dlci_close(struct gsm_dlci *dlci)
1408{
1409 del_timer(&dlci->t1);
1410 if (debug & 8)
Alan Cox5f9a31d2010-11-04 15:17:27 +00001411 pr_debug("DLCI %d goes closed.\n", dlci->addr);
Alan Coxe1eaea42010-03-26 11:32:54 +00001412 dlci->state = DLCI_CLOSED;
1413 if (dlci->addr != 0) {
1414 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1415 if (tty) {
1416 tty_hangup(tty);
1417 tty_kref_put(tty);
1418 }
1419 kfifo_reset(dlci->fifo);
1420 } else
1421 dlci->gsm->dead = 1;
1422 wake_up(&dlci->gsm->event);
1423 /* A DLCI 0 close is a MUX termination so we need to kick that
1424 back to userspace somehow */
1425}
1426
1427/**
1428 * gsm_dlci_open - a DLCI has opened
1429 * @dlci: DLCI that opened
1430 *
1431 * Perform processing when moving a DLCI into open state.
1432 */
1433
1434static void gsm_dlci_open(struct gsm_dlci *dlci)
1435{
1436 /* Note that SABM UA .. SABM UA first UA lost can mean that we go
1437 open -> open */
1438 del_timer(&dlci->t1);
1439 /* This will let a tty open continue */
1440 dlci->state = DLCI_OPEN;
1441 if (debug & 8)
Alan Cox5f9a31d2010-11-04 15:17:27 +00001442 pr_debug("DLCI %d goes open.\n", dlci->addr);
Alan Coxe1eaea42010-03-26 11:32:54 +00001443 wake_up(&dlci->gsm->event);
1444}
1445
1446/**
1447 * gsm_dlci_t1 - T1 timer expiry
1448 * @dlci: DLCI that opened
1449 *
1450 * The T1 timer handles retransmits of control frames (essentially of
1451 * SABM and DISC). We resend the command until the retry count runs out
1452 * in which case an opening port goes back to closed and a closing port
1453 * is simply put into closed state (any further frames from the other
1454 * end will get a DM response)
1455 */
1456
1457static void gsm_dlci_t1(unsigned long data)
1458{
1459 struct gsm_dlci *dlci = (struct gsm_dlci *)data;
1460 struct gsm_mux *gsm = dlci->gsm;
1461
1462 switch (dlci->state) {
1463 case DLCI_OPENING:
1464 dlci->retries--;
1465 if (dlci->retries) {
1466 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1467 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1468 } else
1469 gsm_dlci_close(dlci);
1470 break;
1471 case DLCI_CLOSING:
1472 dlci->retries--;
1473 if (dlci->retries) {
1474 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1475 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1476 } else
1477 gsm_dlci_close(dlci);
1478 break;
1479 }
1480}
1481
1482/**
1483 * gsm_dlci_begin_open - start channel open procedure
1484 * @dlci: DLCI to open
1485 *
1486 * Commence opening a DLCI from the Linux side. We issue SABM messages
1487 * to the modem which should then reply with a UA, at which point we
1488 * will move into open state. Opening is done asynchronously with retry
1489 * running off timers and the responses.
1490 */
1491
1492static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
1493{
1494 struct gsm_mux *gsm = dlci->gsm;
1495 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING)
1496 return;
1497 dlci->retries = gsm->n2;
1498 dlci->state = DLCI_OPENING;
1499 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1500 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1501}
1502
1503/**
1504 * gsm_dlci_begin_close - start channel open procedure
1505 * @dlci: DLCI to open
1506 *
1507 * Commence closing a DLCI from the Linux side. We issue DISC messages
1508 * to the modem which should then reply with a UA, at which point we
1509 * will move into closed state. Closing is done asynchronously with retry
1510 * off timers. We may also receive a DM reply from the other end which
1511 * indicates the channel was already closed.
1512 */
1513
1514static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
1515{
1516 struct gsm_mux *gsm = dlci->gsm;
1517 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
1518 return;
1519 dlci->retries = gsm->n2;
1520 dlci->state = DLCI_CLOSING;
1521 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1522 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1523}
1524
1525/**
1526 * gsm_dlci_data - data arrived
1527 * @dlci: channel
1528 * @data: block of bytes received
1529 * @len: length of received block
1530 *
1531 * A UI or UIH frame has arrived which contains data for a channel
1532 * other than the control channel. If the relevant virtual tty is
1533 * open we shovel the bits down it, if not we drop them.
1534 */
1535
Russ Gorby72632872011-06-14 13:23:28 -07001536static void gsm_dlci_data(struct gsm_dlci *dlci, u8 *data, int clen)
Alan Coxe1eaea42010-03-26 11:32:54 +00001537{
1538 /* krefs .. */
1539 struct tty_port *port = &dlci->port;
1540 struct tty_struct *tty = tty_port_tty_get(port);
1541 unsigned int modem = 0;
Russ Gorby72632872011-06-14 13:23:28 -07001542 int len = clen;
Alan Coxe1eaea42010-03-26 11:32:54 +00001543
1544 if (debug & 16)
Alan Cox5f9a31d2010-11-04 15:17:27 +00001545 pr_debug("%d bytes for tty %p\n", len, tty);
Alan Coxe1eaea42010-03-26 11:32:54 +00001546 if (tty) {
1547 switch (dlci->adaption) {
Alan Cox5f9a31d2010-11-04 15:17:27 +00001548 /* Unsupported types */
1549 /* Packetised interruptible data */
1550 case 4:
1551 break;
1552 /* Packetised uininterruptible voice/data */
1553 case 3:
1554 break;
1555 /* Asynchronous serial with line state in each frame */
1556 case 2:
1557 while (gsm_read_ea(&modem, *data++) == 0) {
1558 len--;
1559 if (len == 0)
1560 return;
1561 }
Russ Gorby72632872011-06-14 13:23:28 -07001562 gsm_process_modem(tty, dlci, modem, clen);
Alan Cox5f9a31d2010-11-04 15:17:27 +00001563 /* Line state will go via DLCI 0 controls only */
1564 case 1:
1565 default:
1566 tty_insert_flip_string(tty, data, len);
1567 tty_flip_buffer_push(tty);
Alan Coxe1eaea42010-03-26 11:32:54 +00001568 }
1569 tty_kref_put(tty);
1570 }
1571}
1572
1573/**
1574 * gsm_dlci_control - data arrived on control channel
1575 * @dlci: channel
1576 * @data: block of bytes received
1577 * @len: length of received block
1578 *
1579 * A UI or UIH frame has arrived which contains data for DLCI 0 the
1580 * control channel. This should contain a command EA followed by
1581 * control data bytes. The command EA contains a command/response bit
1582 * and we divide up the work accordingly.
1583 */
1584
1585static void gsm_dlci_command(struct gsm_dlci *dlci, u8 *data, int len)
1586{
1587 /* See what command is involved */
1588 unsigned int command = 0;
1589 while (len-- > 0) {
1590 if (gsm_read_ea(&command, *data++) == 1) {
1591 int clen = *data++;
1592 len--;
1593 /* FIXME: this is properly an EA */
1594 clen >>= 1;
1595 /* Malformed command ? */
1596 if (clen > len)
1597 return;
1598 if (command & 1)
1599 gsm_control_message(dlci->gsm, command,
1600 data, clen);
1601 else
1602 gsm_control_response(dlci->gsm, command,
1603 data, clen);
1604 return;
1605 }
1606 }
1607}
1608
1609/*
1610 * Allocate/Free DLCI channels
1611 */
1612
1613/**
1614 * gsm_dlci_alloc - allocate a DLCI
1615 * @gsm: GSM mux
1616 * @addr: address of the DLCI
1617 *
1618 * Allocate and install a new DLCI object into the GSM mux.
1619 *
1620 * FIXME: review locking races
1621 */
1622
1623static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
1624{
1625 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC);
1626 if (dlci == NULL)
1627 return NULL;
1628 spin_lock_init(&dlci->lock);
Russ Gorby6ab8fba2011-06-16 14:20:13 -07001629 kref_init(&dlci->ref);
Russ Gorbybcd5abe2011-06-16 14:20:12 -07001630 mutex_init(&dlci->mutex);
Alan Coxe1eaea42010-03-26 11:32:54 +00001631 dlci->fifo = &dlci->_fifo;
1632 if (kfifo_alloc(&dlci->_fifo, 4096, GFP_KERNEL) < 0) {
1633 kfree(dlci);
1634 return NULL;
1635 }
1636
1637 skb_queue_head_init(&dlci->skb_list);
1638 init_timer(&dlci->t1);
1639 dlci->t1.function = gsm_dlci_t1;
1640 dlci->t1.data = (unsigned long)dlci;
1641 tty_port_init(&dlci->port);
1642 dlci->port.ops = &gsm_port_ops;
1643 dlci->gsm = gsm;
1644 dlci->addr = addr;
1645 dlci->adaption = gsm->adaption;
1646 dlci->state = DLCI_CLOSED;
1647 if (addr)
1648 dlci->data = gsm_dlci_data;
1649 else
1650 dlci->data = gsm_dlci_command;
1651 gsm->dlci[addr] = dlci;
1652 return dlci;
1653}
1654
1655/**
Russ Gorby6ab8fba2011-06-16 14:20:13 -07001656 * gsm_dlci_free - free DLCI
1657 * @dlci: DLCI to free
Alan Coxe1eaea42010-03-26 11:32:54 +00001658 *
Russ Gorby6ab8fba2011-06-16 14:20:13 -07001659 * Free up a DLCI.
Alan Coxe1eaea42010-03-26 11:32:54 +00001660 *
1661 * Can sleep.
1662 */
Russ Gorby6ab8fba2011-06-16 14:20:13 -07001663static void gsm_dlci_free(struct kref *ref)
1664{
1665 struct gsm_dlci *dlci = container_of(ref, struct gsm_dlci, ref);
1666
1667 del_timer_sync(&dlci->t1);
1668 dlci->gsm->dlci[dlci->addr] = NULL;
1669 kfifo_free(dlci->fifo);
1670 while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
1671 kfree_skb(dlci->skb);
1672 kfree(dlci);
1673}
1674
1675static inline void dlci_get(struct gsm_dlci *dlci)
1676{
1677 kref_get(&dlci->ref);
1678}
1679
1680static inline void dlci_put(struct gsm_dlci *dlci)
1681{
1682 kref_put(&dlci->ref, gsm_dlci_free);
1683}
1684
1685/**
1686 * gsm_dlci_release - release DLCI
1687 * @dlci: DLCI to destroy
1688 *
1689 * Release a DLCI. Actual free is deferred until either
1690 * mux is closed or tty is closed - whichever is last.
1691 *
1692 * Can sleep.
1693 */
1694static void gsm_dlci_release(struct gsm_dlci *dlci)
Alan Coxe1eaea42010-03-26 11:32:54 +00001695{
1696 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1697 if (tty) {
1698 tty_vhangup(tty);
1699 tty_kref_put(tty);
1700 }
Russ Gorby6ab8fba2011-06-16 14:20:13 -07001701 dlci_put(dlci);
Alan Coxe1eaea42010-03-26 11:32:54 +00001702}
1703
Alan Coxe1eaea42010-03-26 11:32:54 +00001704/*
1705 * LAPBish link layer logic
1706 */
1707
1708/**
1709 * gsm_queue - a GSM frame is ready to process
1710 * @gsm: pointer to our gsm mux
1711 *
1712 * At this point in time a frame has arrived and been demangled from
1713 * the line encoding. All the differences between the encodings have
1714 * been handled below us and the frame is unpacked into the structures.
1715 * The fcs holds the header FCS but any data FCS must be added here.
1716 */
1717
1718static void gsm_queue(struct gsm_mux *gsm)
1719{
1720 struct gsm_dlci *dlci;
1721 u8 cr;
1722 int address;
1723 /* We have to sneak a look at the packet body to do the FCS.
1724 A somewhat layering violation in the spec */
1725
1726 if ((gsm->control & ~PF) == UI)
1727 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len);
Mikhail Kshevetskiy9db4e432011-03-27 04:05:00 +04001728 if (gsm->encoding == 0){
1729 /* WARNING: gsm->received_fcs is used for gsm->encoding = 0 only.
1730 In this case it contain the last piece of data
1731 required to generate final CRC */
1732 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs);
1733 }
Alan Coxe1eaea42010-03-26 11:32:54 +00001734 if (gsm->fcs != GOOD_FCS) {
1735 gsm->bad_fcs++;
1736 if (debug & 4)
Alan Cox5f9a31d2010-11-04 15:17:27 +00001737 pr_debug("BAD FCS %02x\n", gsm->fcs);
Alan Coxe1eaea42010-03-26 11:32:54 +00001738 return;
1739 }
1740 address = gsm->address >> 1;
1741 if (address >= NUM_DLCI)
1742 goto invalid;
1743
1744 cr = gsm->address & 1; /* C/R bit */
1745
1746 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
1747
1748 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */
1749 dlci = gsm->dlci[address];
1750
1751 switch (gsm->control) {
1752 case SABM|PF:
1753 if (cr == 0)
1754 goto invalid;
1755 if (dlci == NULL)
1756 dlci = gsm_dlci_alloc(gsm, address);
1757 if (dlci == NULL)
1758 return;
1759 if (dlci->dead)
1760 gsm_response(gsm, address, DM);
1761 else {
1762 gsm_response(gsm, address, UA);
1763 gsm_dlci_open(dlci);
1764 }
1765 break;
1766 case DISC|PF:
1767 if (cr == 0)
1768 goto invalid;
1769 if (dlci == NULL || dlci->state == DLCI_CLOSED) {
1770 gsm_response(gsm, address, DM);
1771 return;
1772 }
1773 /* Real close complete */
1774 gsm_response(gsm, address, UA);
1775 gsm_dlci_close(dlci);
1776 break;
1777 case UA:
1778 case UA|PF:
1779 if (cr == 0 || dlci == NULL)
1780 break;
1781 switch (dlci->state) {
1782 case DLCI_CLOSING:
1783 gsm_dlci_close(dlci);
1784 break;
1785 case DLCI_OPENING:
1786 gsm_dlci_open(dlci);
1787 break;
1788 }
1789 break;
1790 case DM: /* DM can be valid unsolicited */
1791 case DM|PF:
1792 if (cr)
1793 goto invalid;
1794 if (dlci == NULL)
1795 return;
1796 gsm_dlci_close(dlci);
1797 break;
1798 case UI:
1799 case UI|PF:
1800 case UIH:
1801 case UIH|PF:
1802#if 0
1803 if (cr)
1804 goto invalid;
1805#endif
1806 if (dlci == NULL || dlci->state != DLCI_OPEN) {
1807 gsm_command(gsm, address, DM|PF);
1808 return;
1809 }
1810 dlci->data(dlci, gsm->buf, gsm->len);
1811 break;
1812 default:
1813 goto invalid;
1814 }
1815 return;
1816invalid:
1817 gsm->malformed++;
1818 return;
1819}
1820
1821
1822/**
1823 * gsm0_receive - perform processing for non-transparency
1824 * @gsm: gsm data for this ldisc instance
1825 * @c: character
1826 *
1827 * Receive bytes in gsm mode 0
1828 */
1829
1830static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
1831{
Alan Coxc2f2f002010-11-04 15:17:03 +00001832 unsigned int len;
1833
Alan Coxe1eaea42010-03-26 11:32:54 +00001834 switch (gsm->state) {
1835 case GSM_SEARCH: /* SOF marker */
1836 if (c == GSM0_SOF) {
1837 gsm->state = GSM_ADDRESS;
1838 gsm->address = 0;
1839 gsm->len = 0;
1840 gsm->fcs = INIT_FCS;
1841 }
Alan Coxc2f2f002010-11-04 15:17:03 +00001842 break;
1843 case GSM_ADDRESS: /* Address EA */
Alan Coxe1eaea42010-03-26 11:32:54 +00001844 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1845 if (gsm_read_ea(&gsm->address, c))
1846 gsm->state = GSM_CONTROL;
1847 break;
1848 case GSM_CONTROL: /* Control Byte */
1849 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1850 gsm->control = c;
Alan Coxc2f2f002010-11-04 15:17:03 +00001851 gsm->state = GSM_LEN0;
Alan Coxe1eaea42010-03-26 11:32:54 +00001852 break;
Alan Coxc2f2f002010-11-04 15:17:03 +00001853 case GSM_LEN0: /* Length EA */
Alan Coxe1eaea42010-03-26 11:32:54 +00001854 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1855 if (gsm_read_ea(&gsm->len, c)) {
1856 if (gsm->len > gsm->mru) {
1857 gsm->bad_size++;
1858 gsm->state = GSM_SEARCH;
1859 break;
1860 }
1861 gsm->count = 0;
Alan Coxc2f2f002010-11-04 15:17:03 +00001862 if (!gsm->len)
1863 gsm->state = GSM_FCS;
1864 else
1865 gsm->state = GSM_DATA;
1866 break;
Alan Coxe1eaea42010-03-26 11:32:54 +00001867 }
Alan Coxc2f2f002010-11-04 15:17:03 +00001868 gsm->state = GSM_LEN1;
1869 break;
1870 case GSM_LEN1:
1871 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1872 len = c;
1873 gsm->len |= len << 7;
1874 if (gsm->len > gsm->mru) {
1875 gsm->bad_size++;
1876 gsm->state = GSM_SEARCH;
1877 break;
1878 }
1879 gsm->count = 0;
1880 if (!gsm->len)
1881 gsm->state = GSM_FCS;
1882 else
1883 gsm->state = GSM_DATA;
Alan Coxe1eaea42010-03-26 11:32:54 +00001884 break;
1885 case GSM_DATA: /* Data */
1886 gsm->buf[gsm->count++] = c;
1887 if (gsm->count == gsm->len)
1888 gsm->state = GSM_FCS;
1889 break;
1890 case GSM_FCS: /* FCS follows the packet */
Alan Coxc2f2f002010-11-04 15:17:03 +00001891 gsm->received_fcs = c;
Alan Coxe1eaea42010-03-26 11:32:54 +00001892 gsm_queue(gsm);
Alan Coxc2f2f002010-11-04 15:17:03 +00001893 gsm->state = GSM_SSOF;
1894 break;
1895 case GSM_SSOF:
1896 if (c == GSM0_SOF) {
1897 gsm->state = GSM_SEARCH;
1898 break;
1899 }
Alan Coxe1eaea42010-03-26 11:32:54 +00001900 break;
1901 }
1902}
1903
1904/**
Alan Coxc2f2f002010-11-04 15:17:03 +00001905 * gsm1_receive - perform processing for non-transparency
Alan Coxe1eaea42010-03-26 11:32:54 +00001906 * @gsm: gsm data for this ldisc instance
1907 * @c: character
1908 *
1909 * Receive bytes in mode 1 (Advanced option)
1910 */
1911
1912static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
1913{
1914 if (c == GSM1_SOF) {
1915 /* EOF is only valid in frame if we have got to the data state
1916 and received at least one byte (the FCS) */
1917 if (gsm->state == GSM_DATA && gsm->count) {
1918 /* Extract the FCS */
1919 gsm->count--;
1920 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
1921 gsm->len = gsm->count;
1922 gsm_queue(gsm);
1923 gsm->state = GSM_START;
1924 return;
1925 }
1926 /* Any partial frame was a runt so go back to start */
1927 if (gsm->state != GSM_START) {
1928 gsm->malformed++;
1929 gsm->state = GSM_START;
1930 }
1931 /* A SOF in GSM_START means we are still reading idling or
1932 framing bytes */
1933 return;
1934 }
1935
1936 if (c == GSM1_ESCAPE) {
1937 gsm->escape = 1;
1938 return;
1939 }
1940
1941 /* Only an unescaped SOF gets us out of GSM search */
1942 if (gsm->state == GSM_SEARCH)
1943 return;
1944
1945 if (gsm->escape) {
1946 c ^= GSM1_ESCAPE_BITS;
1947 gsm->escape = 0;
1948 }
1949 switch (gsm->state) {
1950 case GSM_START: /* First byte after SOF */
1951 gsm->address = 0;
1952 gsm->state = GSM_ADDRESS;
1953 gsm->fcs = INIT_FCS;
1954 /* Drop through */
1955 case GSM_ADDRESS: /* Address continuation */
1956 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1957 if (gsm_read_ea(&gsm->address, c))
1958 gsm->state = GSM_CONTROL;
1959 break;
1960 case GSM_CONTROL: /* Control Byte */
1961 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1962 gsm->control = c;
1963 gsm->count = 0;
1964 gsm->state = GSM_DATA;
1965 break;
1966 case GSM_DATA: /* Data */
Alan Cox5f9a31d2010-11-04 15:17:27 +00001967 if (gsm->count > gsm->mru) { /* Allow one for the FCS */
Alan Coxe1eaea42010-03-26 11:32:54 +00001968 gsm->state = GSM_OVERRUN;
1969 gsm->bad_size++;
1970 } else
1971 gsm->buf[gsm->count++] = c;
1972 break;
1973 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */
1974 break;
1975 }
1976}
1977
1978/**
1979 * gsm_error - handle tty error
1980 * @gsm: ldisc data
1981 * @data: byte received (may be invalid)
1982 * @flag: error received
1983 *
1984 * Handle an error in the receipt of data for a frame. Currently we just
1985 * go back to hunting for a SOF.
1986 *
1987 * FIXME: better diagnostics ?
1988 */
1989
1990static void gsm_error(struct gsm_mux *gsm,
1991 unsigned char data, unsigned char flag)
1992{
1993 gsm->state = GSM_SEARCH;
1994 gsm->io_error++;
1995}
1996
1997/**
1998 * gsm_cleanup_mux - generic GSM protocol cleanup
1999 * @gsm: our mux
2000 *
2001 * Clean up the bits of the mux which are the same for all framing
2002 * protocols. Remove the mux from the mux table, stop all the timers
2003 * and then shut down each device hanging up the channels as we go.
2004 */
2005
2006void gsm_cleanup_mux(struct gsm_mux *gsm)
2007{
2008 int i;
2009 struct gsm_dlci *dlci = gsm->dlci[0];
2010 struct gsm_msg *txq;
Alan Coxf17141f2011-08-26 11:28:11 +01002011 struct gsm_control *gc;
Alan Coxe1eaea42010-03-26 11:32:54 +00002012
2013 gsm->dead = 1;
2014
2015 spin_lock(&gsm_mux_lock);
2016 for (i = 0; i < MAX_MUX; i++) {
2017 if (gsm_mux[i] == gsm) {
2018 gsm_mux[i] = NULL;
2019 break;
2020 }
2021 }
2022 spin_unlock(&gsm_mux_lock);
2023 WARN_ON(i == MAX_MUX);
2024
Alan Coxf17141f2011-08-26 11:28:11 +01002025 /* In theory disconnecting DLCI 0 is sufficient but for some
2026 modems this is apparently not the case. */
2027 if (dlci) {
2028 gc = gsm_control_send(gsm, CMD_CLD, NULL, 0);
2029 if (gc)
2030 gsm_control_wait(gsm, gc);
2031 }
Alan Coxe1eaea42010-03-26 11:32:54 +00002032 del_timer_sync(&gsm->t2_timer);
2033 /* Now we are sure T2 has stopped */
2034 if (dlci) {
2035 dlci->dead = 1;
2036 gsm_dlci_begin_close(dlci);
2037 wait_event_interruptible(gsm->event,
2038 dlci->state == DLCI_CLOSED);
2039 }
2040 /* Free up any link layer users */
2041 for (i = 0; i < NUM_DLCI; i++)
2042 if (gsm->dlci[i])
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002043 gsm_dlci_release(gsm->dlci[i]);
Alan Coxe1eaea42010-03-26 11:32:54 +00002044 /* Now wipe the queues */
2045 for (txq = gsm->tx_head; txq != NULL; txq = gsm->tx_head) {
2046 gsm->tx_head = txq->next;
2047 kfree(txq);
2048 }
2049 gsm->tx_tail = NULL;
2050}
2051EXPORT_SYMBOL_GPL(gsm_cleanup_mux);
2052
2053/**
2054 * gsm_activate_mux - generic GSM setup
2055 * @gsm: our mux
2056 *
2057 * Set up the bits of the mux which are the same for all framing
2058 * protocols. Add the mux to the mux table so it can be opened and
2059 * finally kick off connecting to DLCI 0 on the modem.
2060 */
2061
2062int gsm_activate_mux(struct gsm_mux *gsm)
2063{
2064 struct gsm_dlci *dlci;
2065 int i = 0;
2066
2067 init_timer(&gsm->t2_timer);
2068 gsm->t2_timer.function = gsm_control_retransmit;
2069 gsm->t2_timer.data = (unsigned long)gsm;
2070 init_waitqueue_head(&gsm->event);
2071 spin_lock_init(&gsm->control_lock);
2072 spin_lock_init(&gsm->tx_lock);
2073
2074 if (gsm->encoding == 0)
2075 gsm->receive = gsm0_receive;
2076 else
2077 gsm->receive = gsm1_receive;
2078 gsm->error = gsm_error;
2079
2080 spin_lock(&gsm_mux_lock);
2081 for (i = 0; i < MAX_MUX; i++) {
2082 if (gsm_mux[i] == NULL) {
Russ Gorbyd50f6dc2011-06-14 13:35:32 -07002083 gsm->num = i;
Alan Coxe1eaea42010-03-26 11:32:54 +00002084 gsm_mux[i] = gsm;
2085 break;
2086 }
2087 }
2088 spin_unlock(&gsm_mux_lock);
2089 if (i == MAX_MUX)
2090 return -EBUSY;
2091
2092 dlci = gsm_dlci_alloc(gsm, 0);
2093 if (dlci == NULL)
2094 return -ENOMEM;
2095 gsm->dead = 0; /* Tty opens are now permissible */
2096 return 0;
2097}
2098EXPORT_SYMBOL_GPL(gsm_activate_mux);
2099
2100/**
2101 * gsm_free_mux - free up a mux
2102 * @mux: mux to free
2103 *
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002104 * Dispose of allocated resources for a dead mux
Alan Coxe1eaea42010-03-26 11:32:54 +00002105 */
2106void gsm_free_mux(struct gsm_mux *gsm)
2107{
2108 kfree(gsm->txframe);
2109 kfree(gsm->buf);
2110 kfree(gsm);
2111}
2112EXPORT_SYMBOL_GPL(gsm_free_mux);
2113
2114/**
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002115 * gsm_free_muxr - free up a mux
2116 * @mux: mux to free
2117 *
2118 * Dispose of allocated resources for a dead mux
2119 */
2120static void gsm_free_muxr(struct kref *ref)
2121{
2122 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref);
2123 gsm_free_mux(gsm);
2124}
2125
2126static inline void mux_get(struct gsm_mux *gsm)
2127{
2128 kref_get(&gsm->ref);
2129}
2130
2131static inline void mux_put(struct gsm_mux *gsm)
2132{
2133 kref_put(&gsm->ref, gsm_free_muxr);
2134}
2135
2136/**
Alan Coxe1eaea42010-03-26 11:32:54 +00002137 * gsm_alloc_mux - allocate a mux
2138 *
2139 * Creates a new mux ready for activation.
2140 */
2141
2142struct gsm_mux *gsm_alloc_mux(void)
2143{
2144 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
2145 if (gsm == NULL)
2146 return NULL;
2147 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL);
2148 if (gsm->buf == NULL) {
2149 kfree(gsm);
2150 return NULL;
2151 }
2152 gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL);
2153 if (gsm->txframe == NULL) {
2154 kfree(gsm->buf);
2155 kfree(gsm);
2156 return NULL;
2157 }
2158 spin_lock_init(&gsm->lock);
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002159 kref_init(&gsm->ref);
Alan Coxe1eaea42010-03-26 11:32:54 +00002160
2161 gsm->t1 = T1;
2162 gsm->t2 = T2;
2163 gsm->n2 = N2;
2164 gsm->ftype = UIH;
Alan Coxe1eaea42010-03-26 11:32:54 +00002165 gsm->adaption = 1;
2166 gsm->encoding = 1;
2167 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
2168 gsm->mtu = 64;
2169 gsm->dead = 1; /* Avoid early tty opens */
2170
2171 return gsm;
2172}
2173EXPORT_SYMBOL_GPL(gsm_alloc_mux);
2174
Alan Coxe1eaea42010-03-26 11:32:54 +00002175/**
2176 * gsmld_output - write to link
2177 * @gsm: our mux
2178 * @data: bytes to output
2179 * @len: size
2180 *
2181 * Write a block of data from the GSM mux to the data channel. This
2182 * will eventually be serialized from above but at the moment isn't.
2183 */
2184
2185static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
2186{
2187 if (tty_write_room(gsm->tty) < len) {
2188 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
2189 return -ENOSPC;
2190 }
Joe Perches0a77c4f2011-04-25 16:46:49 -07002191 if (debug & 4)
2192 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET,
2193 data, len);
Alan Coxe1eaea42010-03-26 11:32:54 +00002194 gsm->tty->ops->write(gsm->tty, data, len);
2195 return len;
2196}
2197
2198/**
2199 * gsmld_attach_gsm - mode set up
2200 * @tty: our tty structure
2201 * @gsm: our mux
2202 *
2203 * Set up the MUX for basic mode and commence connecting to the
2204 * modem. Currently called from the line discipline set up but
2205 * will need moving to an ioctl path.
2206 */
2207
2208static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2209{
Russ Gorbyd50f6dc2011-06-14 13:35:32 -07002210 int ret, i;
2211 int base = gsm->num << 6; /* Base for this MUX */
Alan Coxe1eaea42010-03-26 11:32:54 +00002212
2213 gsm->tty = tty_kref_get(tty);
2214 gsm->output = gsmld_output;
2215 ret = gsm_activate_mux(gsm);
2216 if (ret != 0)
2217 tty_kref_put(gsm->tty);
Russ Gorbyd50f6dc2011-06-14 13:35:32 -07002218 else {
2219 /* Don't register device 0 - this is the control channel and not
2220 a usable tty interface */
2221 for (i = 1; i < NUM_DLCI; i++)
2222 tty_register_device(gsm_tty_driver, base + i, NULL);
2223 }
Alan Coxe1eaea42010-03-26 11:32:54 +00002224 return ret;
2225}
2226
2227
2228/**
2229 * gsmld_detach_gsm - stop doing 0710 mux
Justin P. Mattock70f23fd2011-05-10 10:16:21 +02002230 * @tty: tty attached to the mux
Alan Coxe1eaea42010-03-26 11:32:54 +00002231 * @gsm: mux
2232 *
2233 * Shutdown and then clean up the resources used by the line discipline
2234 */
2235
2236static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2237{
Russ Gorbyd50f6dc2011-06-14 13:35:32 -07002238 int i;
2239 int base = gsm->num << 6; /* Base for this MUX */
2240
Alan Coxe1eaea42010-03-26 11:32:54 +00002241 WARN_ON(tty != gsm->tty);
Russ Gorbyd50f6dc2011-06-14 13:35:32 -07002242 for (i = 1; i < NUM_DLCI; i++)
2243 tty_unregister_device(gsm_tty_driver, base + i);
Alan Coxe1eaea42010-03-26 11:32:54 +00002244 gsm_cleanup_mux(gsm);
2245 tty_kref_put(gsm->tty);
2246 gsm->tty = NULL;
2247}
2248
Linus Torvalds55db4c62011-06-04 06:33:24 +09002249static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
2250 char *fp, int count)
Alan Coxe1eaea42010-03-26 11:32:54 +00002251{
2252 struct gsm_mux *gsm = tty->disc_data;
2253 const unsigned char *dp;
2254 char *f;
2255 int i;
2256 char buf[64];
2257 char flags;
2258
Joe Perches0a77c4f2011-04-25 16:46:49 -07002259 if (debug & 4)
2260 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET,
2261 cp, count);
Alan Coxe1eaea42010-03-26 11:32:54 +00002262
2263 for (i = count, dp = cp, f = fp; i; i--, dp++) {
2264 flags = *f++;
2265 switch (flags) {
2266 case TTY_NORMAL:
2267 gsm->receive(gsm, *dp);
2268 break;
2269 case TTY_OVERRUN:
2270 case TTY_BREAK:
2271 case TTY_PARITY:
2272 case TTY_FRAME:
2273 gsm->error(gsm, *dp, flags);
2274 break;
2275 default:
Alan Cox5f9a31d2010-11-04 15:17:27 +00002276 WARN_ONCE("%s: unknown flag %d\n",
Alan Coxe1eaea42010-03-26 11:32:54 +00002277 tty_name(tty, buf), flags);
2278 break;
2279 }
2280 }
2281 /* FASYNC if needed ? */
2282 /* If clogged call tty_throttle(tty); */
2283}
2284
2285/**
2286 * gsmld_chars_in_buffer - report available bytes
2287 * @tty: tty device
2288 *
2289 * Report the number of characters buffered to be delivered to user
2290 * at this instant in time.
2291 *
2292 * Locking: gsm lock
2293 */
2294
2295static ssize_t gsmld_chars_in_buffer(struct tty_struct *tty)
2296{
2297 return 0;
2298}
2299
2300/**
2301 * gsmld_flush_buffer - clean input queue
2302 * @tty: terminal device
2303 *
2304 * Flush the input buffer. Called when the line discipline is
2305 * being closed, when the tty layer wants the buffer flushed (eg
2306 * at hangup).
2307 */
2308
2309static void gsmld_flush_buffer(struct tty_struct *tty)
2310{
2311}
2312
2313/**
2314 * gsmld_close - close the ldisc for this tty
2315 * @tty: device
2316 *
2317 * Called from the terminal layer when this line discipline is
2318 * being shut down, either because of a close or becsuse of a
2319 * discipline change. The function will not be called while other
2320 * ldisc methods are in progress.
2321 */
2322
2323static void gsmld_close(struct tty_struct *tty)
2324{
2325 struct gsm_mux *gsm = tty->disc_data;
2326
2327 gsmld_detach_gsm(tty, gsm);
2328
2329 gsmld_flush_buffer(tty);
2330 /* Do other clean up here */
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002331 mux_put(gsm);
Alan Coxe1eaea42010-03-26 11:32:54 +00002332}
2333
2334/**
2335 * gsmld_open - open an ldisc
2336 * @tty: terminal to open
2337 *
2338 * Called when this line discipline is being attached to the
2339 * terminal device. Can sleep. Called serialized so that no
2340 * other events will occur in parallel. No further open will occur
2341 * until a close.
2342 */
2343
2344static int gsmld_open(struct tty_struct *tty)
2345{
2346 struct gsm_mux *gsm;
2347
2348 if (tty->ops->write == NULL)
2349 return -EINVAL;
2350
2351 /* Attach our ldisc data */
2352 gsm = gsm_alloc_mux();
2353 if (gsm == NULL)
2354 return -ENOMEM;
2355
2356 tty->disc_data = gsm;
2357 tty->receive_room = 65536;
2358
2359 /* Attach the initial passive connection */
2360 gsm->encoding = 1;
2361 return gsmld_attach_gsm(tty, gsm);
2362}
2363
2364/**
2365 * gsmld_write_wakeup - asynchronous I/O notifier
2366 * @tty: tty device
2367 *
2368 * Required for the ptys, serial driver etc. since processes
2369 * that attach themselves to the master and rely on ASYNC
2370 * IO must be woken up
2371 */
2372
2373static void gsmld_write_wakeup(struct tty_struct *tty)
2374{
2375 struct gsm_mux *gsm = tty->disc_data;
Dan Carpenter328be392010-05-25 11:37:17 +02002376 unsigned long flags;
Alan Coxe1eaea42010-03-26 11:32:54 +00002377
2378 /* Queue poll */
2379 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2380 gsm_data_kick(gsm);
Dan Carpenter328be392010-05-25 11:37:17 +02002381 if (gsm->tx_bytes < TX_THRESH_LO) {
2382 spin_lock_irqsave(&gsm->tx_lock, flags);
Alan Coxe1eaea42010-03-26 11:32:54 +00002383 gsm_dlci_data_sweep(gsm);
Dan Carpenter328be392010-05-25 11:37:17 +02002384 spin_unlock_irqrestore(&gsm->tx_lock, flags);
2385 }
Alan Coxe1eaea42010-03-26 11:32:54 +00002386}
2387
2388/**
2389 * gsmld_read - read function for tty
2390 * @tty: tty device
2391 * @file: file object
2392 * @buf: userspace buffer pointer
2393 * @nr: size of I/O
2394 *
2395 * Perform reads for the line discipline. We are guaranteed that the
2396 * line discipline will not be closed under us but we may get multiple
2397 * parallel readers and must handle this ourselves. We may also get
2398 * a hangup. Always called in user context, may sleep.
2399 *
2400 * This code must be sure never to sleep through a hangup.
2401 */
2402
2403static ssize_t gsmld_read(struct tty_struct *tty, struct file *file,
2404 unsigned char __user *buf, size_t nr)
2405{
2406 return -EOPNOTSUPP;
2407}
2408
2409/**
2410 * gsmld_write - write function for tty
2411 * @tty: tty device
2412 * @file: file object
2413 * @buf: userspace buffer pointer
2414 * @nr: size of I/O
2415 *
2416 * Called when the owner of the device wants to send a frame
2417 * itself (or some other control data). The data is transferred
2418 * as-is and must be properly framed and checksummed as appropriate
2419 * by userspace. Frames are either sent whole or not at all as this
2420 * avoids pain user side.
2421 */
2422
2423static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
2424 const unsigned char *buf, size_t nr)
2425{
2426 int space = tty_write_room(tty);
2427 if (space >= nr)
2428 return tty->ops->write(tty, buf, nr);
2429 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2430 return -ENOBUFS;
2431}
2432
2433/**
2434 * gsmld_poll - poll method for N_GSM0710
2435 * @tty: terminal device
2436 * @file: file accessing it
2437 * @wait: poll table
2438 *
2439 * Called when the line discipline is asked to poll() for data or
2440 * for special events. This code is not serialized with respect to
2441 * other events save open/close.
2442 *
2443 * This code must be sure never to sleep through a hangup.
2444 * Called without the kernel lock held - fine
2445 */
2446
2447static unsigned int gsmld_poll(struct tty_struct *tty, struct file *file,
2448 poll_table *wait)
2449{
2450 unsigned int mask = 0;
2451 struct gsm_mux *gsm = tty->disc_data;
2452
2453 poll_wait(file, &tty->read_wait, wait);
2454 poll_wait(file, &tty->write_wait, wait);
2455 if (tty_hung_up_p(file))
2456 mask |= POLLHUP;
2457 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
2458 mask |= POLLOUT | POLLWRNORM;
2459 if (gsm->dead)
2460 mask |= POLLHUP;
2461 return mask;
2462}
2463
2464static int gsmld_config(struct tty_struct *tty, struct gsm_mux *gsm,
2465 struct gsm_config *c)
2466{
2467 int need_close = 0;
2468 int need_restart = 0;
2469
2470 /* Stuff we don't support yet - UI or I frame transport, windowing */
Alan Cox5f9a31d2010-11-04 15:17:27 +00002471 if ((c->adaption != 1 && c->adaption != 2) || c->k)
Alan Coxe1eaea42010-03-26 11:32:54 +00002472 return -EOPNOTSUPP;
2473 /* Check the MRU/MTU range looks sane */
2474 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8)
2475 return -EINVAL;
2476 if (c->n2 < 3)
2477 return -EINVAL;
2478 if (c->encapsulation > 1) /* Basic, advanced, no I */
2479 return -EINVAL;
2480 if (c->initiator > 1)
2481 return -EINVAL;
2482 if (c->i == 0 || c->i > 2) /* UIH and UI only */
2483 return -EINVAL;
2484 /*
2485 * See what is needed for reconfiguration
2486 */
2487
2488 /* Timing fields */
2489 if (c->t1 != 0 && c->t1 != gsm->t1)
2490 need_restart = 1;
2491 if (c->t2 != 0 && c->t2 != gsm->t2)
2492 need_restart = 1;
2493 if (c->encapsulation != gsm->encoding)
2494 need_restart = 1;
2495 if (c->adaption != gsm->adaption)
2496 need_restart = 1;
2497 /* Requires care */
2498 if (c->initiator != gsm->initiator)
2499 need_close = 1;
2500 if (c->mru != gsm->mru)
2501 need_restart = 1;
2502 if (c->mtu != gsm->mtu)
2503 need_restart = 1;
2504
2505 /*
2506 * Close down what is needed, restart and initiate the new
2507 * configuration
2508 */
2509
2510 if (need_close || need_restart) {
2511 gsm_dlci_begin_close(gsm->dlci[0]);
2512 /* This will timeout if the link is down due to N2 expiring */
2513 wait_event_interruptible(gsm->event,
2514 gsm->dlci[0]->state == DLCI_CLOSED);
2515 if (signal_pending(current))
2516 return -EINTR;
2517 }
2518 if (need_restart)
2519 gsm_cleanup_mux(gsm);
2520
2521 gsm->initiator = c->initiator;
2522 gsm->mru = c->mru;
Ken Mills91f78f32011-01-25 14:17:45 +00002523 gsm->mtu = c->mtu;
Alan Coxe1eaea42010-03-26 11:32:54 +00002524 gsm->encoding = c->encapsulation;
2525 gsm->adaption = c->adaption;
Ken Mills820e62e2010-11-04 15:16:24 +00002526 gsm->n2 = c->n2;
Alan Coxe1eaea42010-03-26 11:32:54 +00002527
2528 if (c->i == 1)
2529 gsm->ftype = UIH;
2530 else if (c->i == 2)
2531 gsm->ftype = UI;
2532
2533 if (c->t1)
2534 gsm->t1 = c->t1;
2535 if (c->t2)
2536 gsm->t2 = c->t2;
2537
2538 /* FIXME: We need to separate activation/deactivation from adding
2539 and removing from the mux array */
2540 if (need_restart)
2541 gsm_activate_mux(gsm);
2542 if (gsm->initiator && need_close)
2543 gsm_dlci_begin_open(gsm->dlci[0]);
2544 return 0;
2545}
2546
2547static int gsmld_ioctl(struct tty_struct *tty, struct file *file,
2548 unsigned int cmd, unsigned long arg)
2549{
2550 struct gsm_config c;
2551 struct gsm_mux *gsm = tty->disc_data;
2552
2553 switch (cmd) {
2554 case GSMIOC_GETCONF:
2555 memset(&c, 0, sizeof(c));
2556 c.adaption = gsm->adaption;
2557 c.encapsulation = gsm->encoding;
2558 c.initiator = gsm->initiator;
2559 c.t1 = gsm->t1;
2560 c.t2 = gsm->t2;
2561 c.t3 = 0; /* Not supported */
2562 c.n2 = gsm->n2;
2563 if (gsm->ftype == UIH)
2564 c.i = 1;
2565 else
2566 c.i = 2;
Alan Cox5f9a31d2010-11-04 15:17:27 +00002567 pr_debug("Ftype %d i %d\n", gsm->ftype, c.i);
Alan Coxe1eaea42010-03-26 11:32:54 +00002568 c.mru = gsm->mru;
2569 c.mtu = gsm->mtu;
2570 c.k = 0;
2571 if (copy_to_user((void *)arg, &c, sizeof(c)))
2572 return -EFAULT;
2573 return 0;
2574 case GSMIOC_SETCONF:
2575 if (copy_from_user(&c, (void *)arg, sizeof(c)))
2576 return -EFAULT;
2577 return gsmld_config(tty, gsm, &c);
2578 default:
2579 return n_tty_ioctl_helper(tty, file, cmd, arg);
2580 }
2581}
2582
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002583/*
2584 * Network interface
2585 *
2586 */
2587
2588static int gsm_mux_net_open(struct net_device *net)
2589{
2590 pr_debug("%s called\n", __func__);
2591 netif_start_queue(net);
2592 return 0;
2593}
2594
2595static int gsm_mux_net_close(struct net_device *net)
2596{
2597 netif_stop_queue(net);
2598 return 0;
2599}
2600
2601static struct net_device_stats *gsm_mux_net_get_stats(struct net_device *net)
2602{
2603 return &((struct gsm_mux_net *)netdev_priv(net))->stats;
2604}
2605static void dlci_net_free(struct gsm_dlci *dlci)
2606{
2607 if (!dlci->net) {
2608 WARN_ON(1);
2609 return;
2610 }
2611 dlci->adaption = dlci->prev_adaption;
2612 dlci->data = dlci->prev_data;
2613 free_netdev(dlci->net);
2614 dlci->net = NULL;
2615}
2616static void net_free(struct kref *ref)
2617{
2618 struct gsm_mux_net *mux_net;
2619 struct gsm_dlci *dlci;
2620
2621 mux_net = container_of(ref, struct gsm_mux_net, ref);
2622 dlci = mux_net->dlci;
2623
2624 if (dlci->net) {
2625 unregister_netdev(dlci->net);
2626 dlci_net_free(dlci);
2627 }
2628}
2629
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002630static inline void muxnet_get(struct gsm_mux_net *mux_net)
2631{
2632 kref_get(&mux_net->ref);
2633}
2634
2635static inline void muxnet_put(struct gsm_mux_net *mux_net)
2636{
2637 kref_put(&mux_net->ref, net_free);
2638}
2639
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002640static int gsm_mux_net_start_xmit(struct sk_buff *skb,
2641 struct net_device *net)
2642{
2643 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
2644 struct gsm_dlci *dlci = mux_net->dlci;
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002645 muxnet_get(mux_net);
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002646
2647 skb_queue_head(&dlci->skb_list, skb);
2648 STATS(net).tx_packets++;
2649 STATS(net).tx_bytes += skb->len;
2650 gsm_dlci_data_kick(dlci);
2651 /* And tell the kernel when the last transmit started. */
2652 net->trans_start = jiffies;
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002653 muxnet_put(mux_net);
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002654 return NETDEV_TX_OK;
2655}
2656
2657/* called when a packet did not ack after watchdogtimeout */
2658static void gsm_mux_net_tx_timeout(struct net_device *net)
2659{
2660 /* Tell syslog we are hosed. */
2661 dev_dbg(&net->dev, "Tx timed out.\n");
2662
2663 /* Update statistics */
2664 STATS(net).tx_errors++;
2665}
2666
2667static void gsm_mux_rx_netchar(struct gsm_dlci *dlci,
2668 unsigned char *in_buf, int size)
2669{
2670 struct net_device *net = dlci->net;
2671 struct sk_buff *skb;
2672 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002673 muxnet_get(mux_net);
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002674
2675 /* Allocate an sk_buff */
2676 skb = dev_alloc_skb(size + NET_IP_ALIGN);
2677 if (!skb) {
2678 /* We got no receive buffer. */
2679 STATS(net).rx_dropped++;
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002680 muxnet_put(mux_net);
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002681 return;
2682 }
2683 skb_reserve(skb, NET_IP_ALIGN);
2684 memcpy(skb_put(skb, size), in_buf, size);
2685
2686 skb->dev = net;
2687 skb->protocol = __constant_htons(ETH_P_IP);
2688
2689 /* Ship it off to the kernel */
2690 netif_rx(skb);
2691
2692 /* update out statistics */
2693 STATS(net).rx_packets++;
2694 STATS(net).rx_bytes += size;
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002695 muxnet_put(mux_net);
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002696 return;
2697}
2698
2699int gsm_change_mtu(struct net_device *net, int new_mtu)
2700{
2701 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
2702 if ((new_mtu < 8) || (new_mtu > mux_net->dlci->gsm->mtu))
2703 return -EINVAL;
2704 net->mtu = new_mtu;
2705 return 0;
2706}
2707
2708static void gsm_mux_net_init(struct net_device *net)
2709{
2710 static const struct net_device_ops gsm_netdev_ops = {
2711 .ndo_open = gsm_mux_net_open,
2712 .ndo_stop = gsm_mux_net_close,
2713 .ndo_start_xmit = gsm_mux_net_start_xmit,
2714 .ndo_tx_timeout = gsm_mux_net_tx_timeout,
2715 .ndo_get_stats = gsm_mux_net_get_stats,
2716 .ndo_change_mtu = gsm_change_mtu,
2717 };
2718
2719 net->netdev_ops = &gsm_netdev_ops;
2720
2721 /* fill in the other fields */
2722 net->watchdog_timeo = GSM_NET_TX_TIMEOUT;
2723 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
2724 net->type = ARPHRD_NONE;
2725 net->tx_queue_len = 10;
2726}
2727
2728
2729/* caller holds the dlci mutex */
2730static void gsm_destroy_network(struct gsm_dlci *dlci)
2731{
2732 struct gsm_mux_net *mux_net;
2733
2734 pr_debug("destroy network interface");
2735 if (!dlci->net)
2736 return;
2737 mux_net = (struct gsm_mux_net *)netdev_priv(dlci->net);
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002738 muxnet_put(mux_net);
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002739}
2740
2741
2742/* caller holds the dlci mutex */
2743static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
2744{
2745 char *netname;
2746 int retval = 0;
2747 struct net_device *net;
2748 struct gsm_mux_net *mux_net;
2749
2750 if (!capable(CAP_NET_ADMIN))
2751 return -EPERM;
2752
2753 /* Already in a non tty mode */
2754 if (dlci->adaption > 2)
2755 return -EBUSY;
2756
2757 if (nc->protocol != htons(ETH_P_IP))
2758 return -EPROTONOSUPPORT;
2759
2760 if (nc->adaption != 3 && nc->adaption != 4)
2761 return -EPROTONOSUPPORT;
2762
2763 pr_debug("create network interface");
2764
2765 netname = "gsm%d";
2766 if (nc->if_name[0] != '\0')
2767 netname = nc->if_name;
2768 net = alloc_netdev(sizeof(struct gsm_mux_net),
2769 netname,
2770 gsm_mux_net_init);
2771 if (!net) {
2772 pr_err("alloc_netdev failed");
2773 return -ENOMEM;
2774 }
2775 net->mtu = dlci->gsm->mtu;
2776 mux_net = (struct gsm_mux_net *)netdev_priv(net);
2777 mux_net->dlci = dlci;
2778 kref_init(&mux_net->ref);
2779 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */
2780
2781 /* reconfigure dlci for network */
2782 dlci->prev_adaption = dlci->adaption;
2783 dlci->prev_data = dlci->data;
2784 dlci->adaption = nc->adaption;
2785 dlci->data = gsm_mux_rx_netchar;
2786 dlci->net = net;
2787
2788 pr_debug("register netdev");
2789 retval = register_netdev(net);
2790 if (retval) {
2791 pr_err("network register fail %d\n", retval);
2792 dlci_net_free(dlci);
2793 return retval;
2794 }
2795 return net->ifindex; /* return network index */
2796}
Alan Coxe1eaea42010-03-26 11:32:54 +00002797
2798/* Line discipline for real tty */
2799struct tty_ldisc_ops tty_ldisc_packet = {
2800 .owner = THIS_MODULE,
2801 .magic = TTY_LDISC_MAGIC,
2802 .name = "n_gsm",
2803 .open = gsmld_open,
2804 .close = gsmld_close,
2805 .flush_buffer = gsmld_flush_buffer,
2806 .chars_in_buffer = gsmld_chars_in_buffer,
2807 .read = gsmld_read,
2808 .write = gsmld_write,
2809 .ioctl = gsmld_ioctl,
2810 .poll = gsmld_poll,
2811 .receive_buf = gsmld_receive_buf,
2812 .write_wakeup = gsmld_write_wakeup
2813};
2814
2815/*
2816 * Virtual tty side
2817 */
2818
2819#define TX_SIZE 512
2820
2821static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk)
2822{
2823 u8 modembits[5];
2824 struct gsm_control *ctrl;
2825 int len = 2;
2826
2827 if (brk)
2828 len++;
2829
2830 modembits[0] = len << 1 | EA; /* Data bytes */
2831 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */
2832 modembits[2] = gsm_encode_modem(dlci) << 1 | EA;
2833 if (brk)
2834 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */
2835 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1);
2836 if (ctrl == NULL)
2837 return -ENOMEM;
2838 return gsm_control_wait(dlci->gsm, ctrl);
2839}
2840
2841static int gsm_carrier_raised(struct tty_port *port)
2842{
2843 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2844 /* Not yet open so no carrier info */
2845 if (dlci->state != DLCI_OPEN)
2846 return 0;
2847 if (debug & 2)
2848 return 1;
2849 return dlci->modem_rx & TIOCM_CD;
2850}
2851
2852static void gsm_dtr_rts(struct tty_port *port, int onoff)
2853{
2854 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2855 unsigned int modem_tx = dlci->modem_tx;
2856 if (onoff)
2857 modem_tx |= TIOCM_DTR | TIOCM_RTS;
2858 else
2859 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
2860 if (modem_tx != dlci->modem_tx) {
2861 dlci->modem_tx = modem_tx;
2862 gsmtty_modem_update(dlci, 0);
2863 }
2864}
2865
2866static const struct tty_port_operations gsm_port_ops = {
2867 .carrier_raised = gsm_carrier_raised,
2868 .dtr_rts = gsm_dtr_rts,
2869};
2870
2871
2872static int gsmtty_open(struct tty_struct *tty, struct file *filp)
2873{
2874 struct gsm_mux *gsm;
2875 struct gsm_dlci *dlci;
2876 struct tty_port *port;
2877 unsigned int line = tty->index;
2878 unsigned int mux = line >> 6;
2879
2880 line = line & 0x3F;
2881
2882 if (mux >= MAX_MUX)
2883 return -ENXIO;
2884 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
2885 if (gsm_mux[mux] == NULL)
2886 return -EUNATCH;
2887 if (line == 0 || line > 61) /* 62/63 reserved */
2888 return -ECHRNG;
2889 gsm = gsm_mux[mux];
2890 if (gsm->dead)
2891 return -EL2HLT;
2892 dlci = gsm->dlci[line];
2893 if (dlci == NULL)
2894 dlci = gsm_dlci_alloc(gsm, line);
2895 if (dlci == NULL)
2896 return -ENOMEM;
2897 port = &dlci->port;
2898 port->count++;
2899 tty->driver_data = dlci;
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002900 dlci_get(dlci);
2901 dlci_get(dlci->gsm->dlci[0]);
2902 mux_get(dlci->gsm);
Alan Coxe1eaea42010-03-26 11:32:54 +00002903 tty_port_tty_set(port, tty);
2904
2905 dlci->modem_rx = 0;
2906 /* We could in theory open and close before we wait - eg if we get
2907 a DM straight back. This is ok as that will have caused a hangup */
2908 set_bit(ASYNCB_INITIALIZED, &port->flags);
2909 /* Start sending off SABM messages */
2910 gsm_dlci_begin_open(dlci);
2911 /* And wait for virtual carrier */
2912 return tty_port_block_til_ready(port, tty, filp);
2913}
2914
2915static void gsmtty_close(struct tty_struct *tty, struct file *filp)
2916{
2917 struct gsm_dlci *dlci = tty->driver_data;
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002918 struct gsm_mux *gsm;
2919
Alan Coxe1eaea42010-03-26 11:32:54 +00002920 if (dlci == NULL)
2921 return;
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002922 mutex_lock(&dlci->mutex);
2923 gsm_destroy_network(dlci);
2924 mutex_unlock(&dlci->mutex);
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002925 gsm = dlci->gsm;
Alan Coxe1eaea42010-03-26 11:32:54 +00002926 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002927 goto out;
Alan Coxe1eaea42010-03-26 11:32:54 +00002928 gsm_dlci_begin_close(dlci);
2929 tty_port_close_end(&dlci->port, tty);
2930 tty_port_tty_set(&dlci->port, NULL);
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002931out:
2932 dlci_put(dlci);
2933 dlci_put(gsm->dlci[0]);
2934 mux_put(gsm);
Alan Coxe1eaea42010-03-26 11:32:54 +00002935}
2936
2937static void gsmtty_hangup(struct tty_struct *tty)
2938{
2939 struct gsm_dlci *dlci = tty->driver_data;
2940 tty_port_hangup(&dlci->port);
2941 gsm_dlci_begin_close(dlci);
2942}
2943
2944static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf,
2945 int len)
2946{
2947 struct gsm_dlci *dlci = tty->driver_data;
2948 /* Stuff the bytes into the fifo queue */
2949 int sent = kfifo_in_locked(dlci->fifo, buf, len, &dlci->lock);
2950 /* Need to kick the channel */
2951 gsm_dlci_data_kick(dlci);
2952 return sent;
2953}
2954
2955static int gsmtty_write_room(struct tty_struct *tty)
2956{
2957 struct gsm_dlci *dlci = tty->driver_data;
2958 return TX_SIZE - kfifo_len(dlci->fifo);
2959}
2960
2961static int gsmtty_chars_in_buffer(struct tty_struct *tty)
2962{
2963 struct gsm_dlci *dlci = tty->driver_data;
2964 return kfifo_len(dlci->fifo);
2965}
2966
2967static void gsmtty_flush_buffer(struct tty_struct *tty)
2968{
2969 struct gsm_dlci *dlci = tty->driver_data;
2970 /* Caution needed: If we implement reliable transport classes
2971 then the data being transmitted can't simply be junked once
2972 it has first hit the stack. Until then we can just blow it
2973 away */
2974 kfifo_reset(dlci->fifo);
2975 /* Need to unhook this DLCI from the transmit queue logic */
2976}
2977
2978static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
2979{
2980 /* The FIFO handles the queue so the kernel will do the right
2981 thing waiting on chars_in_buffer before calling us. No work
2982 to do here */
2983}
2984
Alan Cox60b33c12011-02-14 16:26:14 +00002985static int gsmtty_tiocmget(struct tty_struct *tty)
Alan Coxe1eaea42010-03-26 11:32:54 +00002986{
2987 struct gsm_dlci *dlci = tty->driver_data;
2988 return dlci->modem_rx;
2989}
2990
Alan Cox20b9d172011-02-14 16:26:50 +00002991static int gsmtty_tiocmset(struct tty_struct *tty,
Alan Coxe1eaea42010-03-26 11:32:54 +00002992 unsigned int set, unsigned int clear)
2993{
2994 struct gsm_dlci *dlci = tty->driver_data;
2995 unsigned int modem_tx = dlci->modem_tx;
2996
Nikola Diklic-Perincf168072011-09-23 10:59:43 +02002997 modem_tx &= ~clear;
Alan Coxe1eaea42010-03-26 11:32:54 +00002998 modem_tx |= set;
2999
3000 if (modem_tx != dlci->modem_tx) {
3001 dlci->modem_tx = modem_tx;
3002 return gsmtty_modem_update(dlci, 0);
3003 }
3004 return 0;
3005}
3006
3007
Alan Cox6caa76b2011-02-14 16:27:22 +00003008static int gsmtty_ioctl(struct tty_struct *tty,
Alan Coxe1eaea42010-03-26 11:32:54 +00003009 unsigned int cmd, unsigned long arg)
3010{
Russ Gorbybcd5abe2011-06-16 14:20:12 -07003011 struct gsm_dlci *dlci = tty->driver_data;
3012 struct gsm_netconfig nc;
3013 int index;
3014
3015 switch (cmd) {
3016 case GSMIOC_ENABLE_NET:
3017 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc)))
3018 return -EFAULT;
3019 nc.if_name[IFNAMSIZ-1] = '\0';
3020 /* return net interface index or error code */
3021 mutex_lock(&dlci->mutex);
3022 index = gsm_create_network(dlci, &nc);
3023 mutex_unlock(&dlci->mutex);
3024 if (copy_to_user((void __user *)arg, &nc, sizeof(nc)))
3025 return -EFAULT;
3026 return index;
3027 case GSMIOC_DISABLE_NET:
3028 if (!capable(CAP_NET_ADMIN))
3029 return -EPERM;
3030 mutex_lock(&dlci->mutex);
3031 gsm_destroy_network(dlci);
3032 mutex_unlock(&dlci->mutex);
3033 return 0;
3034 default:
3035 return -ENOIOCTLCMD;
3036 }
Alan Coxe1eaea42010-03-26 11:32:54 +00003037}
3038
3039static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old)
3040{
3041 /* For the moment its fixed. In actual fact the speed information
3042 for the virtual channel can be propogated in both directions by
3043 the RPN control message. This however rapidly gets nasty as we
3044 then have to remap modem signals each way according to whether
3045 our virtual cable is null modem etc .. */
3046 tty_termios_copy_hw(tty->termios, old);
3047}
3048
3049static void gsmtty_throttle(struct tty_struct *tty)
3050{
3051 struct gsm_dlci *dlci = tty->driver_data;
3052 if (tty->termios->c_cflag & CRTSCTS)
3053 dlci->modem_tx &= ~TIOCM_DTR;
3054 dlci->throttled = 1;
3055 /* Send an MSC with DTR cleared */
3056 gsmtty_modem_update(dlci, 0);
3057}
3058
3059static void gsmtty_unthrottle(struct tty_struct *tty)
3060{
3061 struct gsm_dlci *dlci = tty->driver_data;
3062 if (tty->termios->c_cflag & CRTSCTS)
3063 dlci->modem_tx |= TIOCM_DTR;
3064 dlci->throttled = 0;
3065 /* Send an MSC with DTR set */
3066 gsmtty_modem_update(dlci, 0);
3067}
3068
3069static int gsmtty_break_ctl(struct tty_struct *tty, int state)
3070{
3071 struct gsm_dlci *dlci = tty->driver_data;
3072 int encode = 0; /* Off */
3073
3074 if (state == -1) /* "On indefinitely" - we can't encode this
3075 properly */
3076 encode = 0x0F;
3077 else if (state > 0) {
3078 encode = state / 200; /* mS to encoding */
3079 if (encode > 0x0F)
3080 encode = 0x0F; /* Best effort */
3081 }
3082 return gsmtty_modem_update(dlci, encode);
3083}
3084
Alan Coxe1eaea42010-03-26 11:32:54 +00003085
3086/* Virtual ttys for the demux */
3087static const struct tty_operations gsmtty_ops = {
3088 .open = gsmtty_open,
3089 .close = gsmtty_close,
3090 .write = gsmtty_write,
3091 .write_room = gsmtty_write_room,
3092 .chars_in_buffer = gsmtty_chars_in_buffer,
3093 .flush_buffer = gsmtty_flush_buffer,
3094 .ioctl = gsmtty_ioctl,
3095 .throttle = gsmtty_throttle,
3096 .unthrottle = gsmtty_unthrottle,
3097 .set_termios = gsmtty_set_termios,
3098 .hangup = gsmtty_hangup,
3099 .wait_until_sent = gsmtty_wait_until_sent,
3100 .tiocmget = gsmtty_tiocmget,
3101 .tiocmset = gsmtty_tiocmset,
3102 .break_ctl = gsmtty_break_ctl,
3103};
3104
3105
3106
3107static int __init gsm_init(void)
3108{
3109 /* Fill in our line protocol discipline, and register it */
3110 int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet);
3111 if (status != 0) {
Alan Cox5f9a31d2010-11-04 15:17:27 +00003112 pr_err("n_gsm: can't register line discipline (err = %d)\n",
3113 status);
Alan Coxe1eaea42010-03-26 11:32:54 +00003114 return status;
3115 }
3116
3117 gsm_tty_driver = alloc_tty_driver(256);
3118 if (!gsm_tty_driver) {
3119 tty_unregister_ldisc(N_GSM0710);
Alan Cox5f9a31d2010-11-04 15:17:27 +00003120 pr_err("gsm_init: tty allocation failed.\n");
Alan Coxe1eaea42010-03-26 11:32:54 +00003121 return -EINVAL;
3122 }
3123 gsm_tty_driver->owner = THIS_MODULE;
3124 gsm_tty_driver->driver_name = "gsmtty";
3125 gsm_tty_driver->name = "gsmtty";
3126 gsm_tty_driver->major = 0; /* Dynamic */
3127 gsm_tty_driver->minor_start = 0;
3128 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
3129 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
3130 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV
Alan Cox5f9a31d2010-11-04 15:17:27 +00003131 | TTY_DRIVER_HARDWARE_BREAK;
Alan Coxe1eaea42010-03-26 11:32:54 +00003132 gsm_tty_driver->init_termios = tty_std_termios;
3133 /* Fixme */
3134 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
3135 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
3136
3137 spin_lock_init(&gsm_mux_lock);
3138
3139 if (tty_register_driver(gsm_tty_driver)) {
3140 put_tty_driver(gsm_tty_driver);
3141 tty_unregister_ldisc(N_GSM0710);
Alan Cox5f9a31d2010-11-04 15:17:27 +00003142 pr_err("gsm_init: tty registration failed.\n");
Alan Coxe1eaea42010-03-26 11:32:54 +00003143 return -EBUSY;
3144 }
Alan Cox5f9a31d2010-11-04 15:17:27 +00003145 pr_debug("gsm_init: loaded as %d,%d.\n",
3146 gsm_tty_driver->major, gsm_tty_driver->minor_start);
Alan Coxe1eaea42010-03-26 11:32:54 +00003147 return 0;
3148}
3149
3150static void __exit gsm_exit(void)
3151{
3152 int status = tty_unregister_ldisc(N_GSM0710);
3153 if (status != 0)
Alan Cox5f9a31d2010-11-04 15:17:27 +00003154 pr_err("n_gsm: can't unregister line discipline (err = %d)\n",
3155 status);
Alan Coxe1eaea42010-03-26 11:32:54 +00003156 tty_unregister_driver(gsm_tty_driver);
3157 put_tty_driver(gsm_tty_driver);
Alan Coxe1eaea42010-03-26 11:32:54 +00003158}
3159
3160module_init(gsm_init);
3161module_exit(gsm_exit);
3162
3163
3164MODULE_LICENSE("GPL");
3165MODULE_ALIAS_LDISC(N_GSM0710);