blob: 642239015b46bbe9e18844f186a31296a343d5f9 [file] [log] [blame]
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 {
Russ Gorbyb4338e12012-08-13 13:44:59 +0100111 struct list_head list;
Alan Coxe1eaea42010-03-26 11:32:54 +0000112 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 Gorbybcd5abe2011-06-16 14:20:12 -0700137 struct mutex mutex;
Alan Coxe1eaea42010-03-26 11:32:54 +0000138
139 /* Link layer */
140 spinlock_t lock; /* Protects the internal state */
141 struct timer_list t1; /* Retransmit timer for SABM and UA */
142 int retries;
143 /* Uplink tty if active */
144 struct tty_port port; /* The tty bound to this DLCI if there is one */
145 struct kfifo *fifo; /* Queue fifo for the DLCI */
146 struct kfifo _fifo; /* For new fifo API porting only */
147 int adaption; /* Adaption layer in use */
Russ Gorbybcd5abe2011-06-16 14:20:12 -0700148 int prev_adaption;
Alan Coxe1eaea42010-03-26 11:32:54 +0000149 u32 modem_rx; /* Our incoming virtual modem lines */
150 u32 modem_tx; /* Our outgoing modem lines */
151 int dead; /* Refuse re-open */
152 /* Flow control */
153 int throttled; /* Private copy of throttle state */
154 int constipated; /* Throttle status for outgoing */
155 /* Packetised I/O */
156 struct sk_buff *skb; /* Frame being sent */
157 struct sk_buff_head skb_list; /* Queued frames */
158 /* Data handling callback */
159 void (*data)(struct gsm_dlci *dlci, u8 *data, int len);
Russ Gorbybcd5abe2011-06-16 14:20:12 -0700160 void (*prev_data)(struct gsm_dlci *dlci, u8 *data, int len);
161 struct net_device *net; /* network interface, if created */
Alan Coxe1eaea42010-03-26 11:32:54 +0000162};
163
164/* DLCI 0, 62/63 are special or reseved see gsmtty_open */
165
166#define NUM_DLCI 64
167
168/*
169 * DLCI 0 is used to pass control blocks out of band of the data
170 * flow (and with a higher link priority). One command can be outstanding
171 * at a time and we use this structure to manage them. They are created
172 * and destroyed by the user context, and updated by the receive paths
173 * and timers
174 */
175
176struct gsm_control {
177 u8 cmd; /* Command we are issuing */
178 u8 *data; /* Data for the command in case we retransmit */
179 int len; /* Length of block for retransmission */
180 int done; /* Done flag */
181 int error; /* Error if any */
182};
183
184/*
185 * Each GSM mux we have is represented by this structure. If we are
186 * operating as an ldisc then we use this structure as our ldisc
187 * state. We need to sort out lifetimes and locking with respect
188 * to the gsm mux array. For now we don't free DLCI objects that
189 * have been instantiated until the mux itself is terminated.
190 *
191 * To consider further: tty open versus mux shutdown.
192 */
193
194struct gsm_mux {
195 struct tty_struct *tty; /* The tty our ldisc is bound to */
196 spinlock_t lock;
Russ Gorbyd50f6dc2011-06-14 13:35:32 -0700197 unsigned int num;
Russ Gorby6ab8fba2011-06-16 14:20:13 -0700198 struct kref ref;
Alan Coxe1eaea42010-03-26 11:32:54 +0000199
200 /* Events on the GSM channel */
201 wait_queue_head_t event;
202
203 /* Bits for GSM mode decoding */
204
205 /* Framing Layer */
206 unsigned char *buf;
207 int state;
208#define GSM_SEARCH 0
209#define GSM_START 1
210#define GSM_ADDRESS 2
211#define GSM_CONTROL 3
212#define GSM_LEN 4
213#define GSM_DATA 5
214#define GSM_FCS 6
215#define GSM_OVERRUN 7
Alan Coxc2f2f002010-11-04 15:17:03 +0000216#define GSM_LEN0 8
217#define GSM_LEN1 9
218#define GSM_SSOF 10
Alan Coxe1eaea42010-03-26 11:32:54 +0000219 unsigned int len;
220 unsigned int address;
221 unsigned int count;
222 int escape;
223 int encoding;
224 u8 control;
225 u8 fcs;
Alan Coxc2f2f002010-11-04 15:17:03 +0000226 u8 received_fcs;
Alan Coxe1eaea42010-03-26 11:32:54 +0000227 u8 *txframe; /* TX framing buffer */
228
229 /* Methods for the receiver side */
230 void (*receive)(struct gsm_mux *gsm, u8 ch);
231 void (*error)(struct gsm_mux *gsm, u8 ch, u8 flag);
232 /* And transmit side */
233 int (*output)(struct gsm_mux *mux, u8 *data, int len);
234
235 /* Link Layer */
236 unsigned int mru;
237 unsigned int mtu;
238 int initiator; /* Did we initiate connection */
239 int dead; /* Has the mux been shut down */
240 struct gsm_dlci *dlci[NUM_DLCI];
241 int constipated; /* Asked by remote to shut up */
242
243 spinlock_t tx_lock;
244 unsigned int tx_bytes; /* TX data outstanding */
245#define TX_THRESH_HI 8192
246#define TX_THRESH_LO 2048
Russ Gorbyb4338e12012-08-13 13:44:59 +0100247 struct list_head tx_list; /* Pending data packets */
Alan Coxe1eaea42010-03-26 11:32:54 +0000248
249 /* Control messages */
250 struct timer_list t2_timer; /* Retransmit timer for commands */
251 int cretries; /* Command retry counter */
252 struct gsm_control *pending_cmd;/* Our current pending command */
253 spinlock_t control_lock; /* Protects the pending command */
254
255 /* Configuration */
256 int adaption; /* 1 or 2 supported */
257 u8 ftype; /* UI or UIH */
258 int t1, t2; /* Timers in 1/100th of a sec */
259 int n2; /* Retry count */
260
261 /* Statistics (not currently exposed) */
262 unsigned long bad_fcs;
263 unsigned long malformed;
264 unsigned long io_error;
265 unsigned long bad_size;
266 unsigned long unsupported;
267};
268
269
270/*
271 * Mux objects - needed so that we can translate a tty index into the
272 * relevant mux and DLCI.
273 */
274
275#define MAX_MUX 4 /* 256 minors */
276static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */
277static spinlock_t gsm_mux_lock;
278
Russ Gorbyd50f6dc2011-06-14 13:35:32 -0700279static struct tty_driver *gsm_tty_driver;
280
Alan Coxe1eaea42010-03-26 11:32:54 +0000281/*
282 * This section of the driver logic implements the GSM encodings
283 * both the basic and the 'advanced'. Reliable transport is not
284 * supported.
285 */
286
287#define CR 0x02
288#define EA 0x01
289#define PF 0x10
290
291/* I is special: the rest are ..*/
292#define RR 0x01
293#define UI 0x03
294#define RNR 0x05
295#define REJ 0x09
296#define DM 0x0F
297#define SABM 0x2F
298#define DISC 0x43
299#define UA 0x63
300#define UIH 0xEF
301
302/* Channel commands */
303#define CMD_NSC 0x09
304#define CMD_TEST 0x11
305#define CMD_PSC 0x21
306#define CMD_RLS 0x29
307#define CMD_FCOFF 0x31
308#define CMD_PN 0x41
309#define CMD_RPN 0x49
310#define CMD_FCON 0x51
311#define CMD_CLD 0x61
312#define CMD_SNC 0x69
313#define CMD_MSC 0x71
314
315/* Virtual modem bits */
316#define MDM_FC 0x01
317#define MDM_RTC 0x02
318#define MDM_RTR 0x04
319#define MDM_IC 0x20
320#define MDM_DV 0x40
321
322#define GSM0_SOF 0xF9
Alan Cox5f9a31d2010-11-04 15:17:27 +0000323#define GSM1_SOF 0x7E
Alan Coxe1eaea42010-03-26 11:32:54 +0000324#define GSM1_ESCAPE 0x7D
325#define GSM1_ESCAPE_BITS 0x20
326#define XON 0x11
327#define XOFF 0x13
328
329static const struct tty_port_operations gsm_port_ops;
330
331/*
332 * CRC table for GSM 0710
333 */
334
335static const u8 gsm_fcs8[256] = {
336 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75,
337 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B,
338 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69,
339 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67,
340 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D,
341 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43,
342 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51,
343 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F,
344 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05,
345 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B,
346 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19,
347 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17,
348 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D,
349 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33,
350 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21,
351 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F,
352 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95,
353 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B,
354 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89,
355 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87,
356 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD,
357 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3,
358 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1,
359 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF,
360 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5,
361 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB,
362 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9,
363 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7,
364 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD,
365 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3,
366 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1,
367 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF
368};
369
370#define INIT_FCS 0xFF
371#define GOOD_FCS 0xCF
372
373/**
374 * gsm_fcs_add - update FCS
375 * @fcs: Current FCS
376 * @c: Next data
377 *
378 * Update the FCS to include c. Uses the algorithm in the specification
379 * notes.
380 */
381
382static inline u8 gsm_fcs_add(u8 fcs, u8 c)
383{
384 return gsm_fcs8[fcs ^ c];
385}
386
387/**
388 * gsm_fcs_add_block - update FCS for a block
389 * @fcs: Current FCS
390 * @c: buffer of data
391 * @len: length of buffer
392 *
393 * Update the FCS to include c. Uses the algorithm in the specification
394 * notes.
395 */
396
397static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len)
398{
399 while (len--)
400 fcs = gsm_fcs8[fcs ^ *c++];
401 return fcs;
402}
403
404/**
405 * gsm_read_ea - read a byte into an EA
406 * @val: variable holding value
407 * c: byte going into the EA
408 *
409 * Processes one byte of an EA. Updates the passed variable
410 * and returns 1 if the EA is now completely read
411 */
412
413static int gsm_read_ea(unsigned int *val, u8 c)
414{
415 /* Add the next 7 bits into the value */
416 *val <<= 7;
417 *val |= c >> 1;
418 /* Was this the last byte of the EA 1 = yes*/
419 return c & EA;
420}
421
422/**
423 * gsm_encode_modem - encode modem data bits
424 * @dlci: DLCI to encode from
425 *
426 * Returns the correct GSM encoded modem status bits (6 bit field) for
427 * the current status of the DLCI and attached tty object
428 */
429
430static u8 gsm_encode_modem(const struct gsm_dlci *dlci)
431{
432 u8 modembits = 0;
433 /* FC is true flow control not modem bits */
434 if (dlci->throttled)
435 modembits |= MDM_FC;
436 if (dlci->modem_tx & TIOCM_DTR)
437 modembits |= MDM_RTC;
438 if (dlci->modem_tx & TIOCM_RTS)
439 modembits |= MDM_RTR;
440 if (dlci->modem_tx & TIOCM_RI)
441 modembits |= MDM_IC;
442 if (dlci->modem_tx & TIOCM_CD)
443 modembits |= MDM_DV;
444 return modembits;
445}
446
447/**
448 * gsm_print_packet - display a frame for debug
449 * @hdr: header to print before decode
450 * @addr: address EA from the frame
451 * @cr: C/R bit from the frame
452 * @control: control including PF bit
453 * @data: following data bytes
454 * @dlen: length of data
455 *
456 * Displays a packet in human readable format for debugging purposes. The
457 * style is based on amateur radio LAP-B dump display.
458 */
459
460static void gsm_print_packet(const char *hdr, int addr, int cr,
461 u8 control, const u8 *data, int dlen)
462{
463 if (!(debug & 1))
464 return;
465
Alan Cox5f9a31d2010-11-04 15:17:27 +0000466 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]);
Alan Coxe1eaea42010-03-26 11:32:54 +0000467
468 switch (control & ~PF) {
469 case SABM:
Alan Cox5f9a31d2010-11-04 15:17:27 +0000470 pr_cont("SABM");
Alan Coxe1eaea42010-03-26 11:32:54 +0000471 break;
472 case UA:
Alan Cox5f9a31d2010-11-04 15:17:27 +0000473 pr_cont("UA");
Alan Coxe1eaea42010-03-26 11:32:54 +0000474 break;
475 case DISC:
Alan Cox5f9a31d2010-11-04 15:17:27 +0000476 pr_cont("DISC");
Alan Coxe1eaea42010-03-26 11:32:54 +0000477 break;
478 case DM:
Alan Cox5f9a31d2010-11-04 15:17:27 +0000479 pr_cont("DM");
Alan Coxe1eaea42010-03-26 11:32:54 +0000480 break;
481 case UI:
Alan Cox5f9a31d2010-11-04 15:17:27 +0000482 pr_cont("UI");
Alan Coxe1eaea42010-03-26 11:32:54 +0000483 break;
484 case UIH:
Alan Cox5f9a31d2010-11-04 15:17:27 +0000485 pr_cont("UIH");
Alan Coxe1eaea42010-03-26 11:32:54 +0000486 break;
487 default:
488 if (!(control & 0x01)) {
Alan Cox5f9a31d2010-11-04 15:17:27 +0000489 pr_cont("I N(S)%d N(R)%d",
Alan Cox47fdd642012-09-17 12:02:35 +0100490 (control & 0x0E) >> 1, (control & 0xE0) >> 5);
Alan Coxe1eaea42010-03-26 11:32:54 +0000491 } else switch (control & 0x0F) {
Alan Cox5f9a31d2010-11-04 15:17:27 +0000492 case RR:
493 pr_cont("RR(%d)", (control & 0xE0) >> 5);
494 break;
495 case RNR:
496 pr_cont("RNR(%d)", (control & 0xE0) >> 5);
497 break;
498 case REJ:
499 pr_cont("REJ(%d)", (control & 0xE0) >> 5);
500 break;
501 default:
502 pr_cont("[%02X]", control);
Alan Coxe1eaea42010-03-26 11:32:54 +0000503 }
504 }
505
506 if (control & PF)
Alan Cox5f9a31d2010-11-04 15:17:27 +0000507 pr_cont("(P)");
Alan Coxe1eaea42010-03-26 11:32:54 +0000508 else
Alan Cox5f9a31d2010-11-04 15:17:27 +0000509 pr_cont("(F)");
Alan Coxe1eaea42010-03-26 11:32:54 +0000510
511 if (dlen) {
512 int ct = 0;
513 while (dlen--) {
Alan Cox5f9a31d2010-11-04 15:17:27 +0000514 if (ct % 8 == 0) {
515 pr_cont("\n");
516 pr_debug(" ");
517 }
518 pr_cont("%02X ", *data++);
Alan Coxe1eaea42010-03-26 11:32:54 +0000519 ct++;
520 }
521 }
Alan Cox5f9a31d2010-11-04 15:17:27 +0000522 pr_cont("\n");
Alan Coxe1eaea42010-03-26 11:32:54 +0000523}
524
525
526/*
527 * Link level transmission side
528 */
529
530/**
531 * gsm_stuff_packet - bytestuff a packet
532 * @ibuf: input
533 * @obuf: output
534 * @len: length of input
535 *
536 * Expand a buffer by bytestuffing it. The worst case size change
537 * is doubling and the caller is responsible for handing out
538 * suitable sized buffers.
539 */
540
541static int gsm_stuff_frame(const u8 *input, u8 *output, int len)
542{
543 int olen = 0;
544 while (len--) {
545 if (*input == GSM1_SOF || *input == GSM1_ESCAPE
546 || *input == XON || *input == XOFF) {
547 *output++ = GSM1_ESCAPE;
548 *output++ = *input++ ^ GSM1_ESCAPE_BITS;
549 olen++;
550 } else
551 *output++ = *input++;
552 olen++;
553 }
554 return olen;
555}
556
Alan Coxe1eaea42010-03-26 11:32:54 +0000557/**
558 * gsm_send - send a control frame
559 * @gsm: our GSM mux
560 * @addr: address for control frame
561 * @cr: command/response bit
562 * @control: control byte including PF bit
563 *
564 * Format up and transmit a control frame. These do not go via the
565 * queueing logic as they should be transmitted ahead of data when
566 * they are needed.
567 *
568 * FIXME: Lock versus data TX path
569 */
570
571static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control)
572{
573 int len;
574 u8 cbuf[10];
575 u8 ibuf[3];
576
577 switch (gsm->encoding) {
578 case 0:
579 cbuf[0] = GSM0_SOF;
580 cbuf[1] = (addr << 2) | (cr << 1) | EA;
581 cbuf[2] = control;
582 cbuf[3] = EA; /* Length of data = 0 */
583 cbuf[4] = 0xFF - gsm_fcs_add_block(INIT_FCS, cbuf + 1, 3);
584 cbuf[5] = GSM0_SOF;
585 len = 6;
586 break;
587 case 1:
588 case 2:
589 /* Control frame + packing (but not frame stuffing) in mode 1 */
590 ibuf[0] = (addr << 2) | (cr << 1) | EA;
591 ibuf[1] = control;
592 ibuf[2] = 0xFF - gsm_fcs_add_block(INIT_FCS, ibuf, 2);
593 /* Stuffing may double the size worst case */
594 len = gsm_stuff_frame(ibuf, cbuf + 1, 3);
595 /* Now add the SOF markers */
596 cbuf[0] = GSM1_SOF;
597 cbuf[len + 1] = GSM1_SOF;
598 /* FIXME: we can omit the lead one in many cases */
599 len += 2;
600 break;
601 default:
602 WARN_ON(1);
603 return;
604 }
605 gsm->output(gsm, cbuf, len);
606 gsm_print_packet("-->", addr, cr, control, NULL, 0);
607}
608
609/**
610 * gsm_response - send a control response
611 * @gsm: our GSM mux
612 * @addr: address for control frame
613 * @control: control byte including PF bit
614 *
615 * Format up and transmit a link level response frame.
616 */
617
618static inline void gsm_response(struct gsm_mux *gsm, int addr, int control)
619{
620 gsm_send(gsm, addr, 0, control);
621}
622
623/**
624 * gsm_command - send a control command
625 * @gsm: our GSM mux
626 * @addr: address for control frame
627 * @control: control byte including PF bit
628 *
629 * Format up and transmit a link level command frame.
630 */
631
632static inline void gsm_command(struct gsm_mux *gsm, int addr, int control)
633{
634 gsm_send(gsm, addr, 1, control);
635}
636
637/* Data transmission */
638
639#define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */
640
641/**
642 * gsm_data_alloc - allocate data frame
643 * @gsm: GSM mux
644 * @addr: DLCI address
645 * @len: length excluding header and FCS
646 * @ctrl: control byte
647 *
648 * Allocate a new data buffer for sending frames with data. Space is left
649 * at the front for header bytes but that is treated as an implementation
650 * detail and not for the high level code to use
651 */
652
653static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
654 u8 ctrl)
655{
656 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN,
657 GFP_ATOMIC);
658 if (m == NULL)
659 return NULL;
660 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */
661 m->len = len;
662 m->addr = addr;
663 m->ctrl = ctrl;
Russ Gorbyb4338e12012-08-13 13:44:59 +0100664 INIT_LIST_HEAD(&m->list);
Alan Coxe1eaea42010-03-26 11:32:54 +0000665 return m;
666}
667
668/**
669 * gsm_data_kick - poke the queue
670 * @gsm: GSM Mux
671 *
672 * The tty device has called us to indicate that room has appeared in
673 * the transmit queue. Ram more data into the pipe if we have any
Frederic Beratc01af4f2012-08-13 13:43:58 +0100674 * If we have been flow-stopped by a CMD_FCOFF, then we can only
675 * send messages on DLCI0 until CMD_FCON
Alan Coxe1eaea42010-03-26 11:32:54 +0000676 *
677 * FIXME: lock against link layer control transmissions
678 */
679
680static void gsm_data_kick(struct gsm_mux *gsm)
681{
Russ Gorbyb4338e12012-08-13 13:44:59 +0100682 struct gsm_msg *msg, *nmsg;
Alan Coxe1eaea42010-03-26 11:32:54 +0000683 int len;
684 int skip_sof = 0;
685
Russ Gorbyb4338e12012-08-13 13:44:59 +0100686 list_for_each_entry_safe(msg, nmsg, &gsm->tx_list, list) {
687 if (gsm->constipated && msg->addr)
Frederic Beratc01af4f2012-08-13 13:43:58 +0100688 continue;
Alan Coxe1eaea42010-03-26 11:32:54 +0000689 if (gsm->encoding != 0) {
690 gsm->txframe[0] = GSM1_SOF;
691 len = gsm_stuff_frame(msg->data,
692 gsm->txframe + 1, msg->len);
693 gsm->txframe[len + 1] = GSM1_SOF;
694 len += 2;
695 } else {
696 gsm->txframe[0] = GSM0_SOF;
697 memcpy(gsm->txframe + 1 , msg->data, msg->len);
698 gsm->txframe[msg->len + 1] = GSM0_SOF;
699 len = msg->len + 2;
700 }
701
Joe Perches0a77c4f2011-04-25 16:46:49 -0700702 if (debug & 4)
703 print_hex_dump_bytes("gsm_data_kick: ",
704 DUMP_PREFIX_OFFSET,
705 gsm->txframe, len);
Alan Coxe1eaea42010-03-26 11:32:54 +0000706
707 if (gsm->output(gsm, gsm->txframe + skip_sof,
708 len - skip_sof) < 0)
709 break;
710 /* FIXME: Can eliminate one SOF in many more cases */
Alan Coxe1eaea42010-03-26 11:32:54 +0000711 gsm->tx_bytes -= msg->len;
Alan Coxe1eaea42010-03-26 11:32:54 +0000712 /* For a burst of frames skip the extra SOF within the
713 burst */
714 skip_sof = 1;
Frederic Beratc01af4f2012-08-13 13:43:58 +0100715
Russ Gorbyb4338e12012-08-13 13:44:59 +0100716 list_del(&msg->list);
717 kfree(msg);
Alan Coxe1eaea42010-03-26 11:32:54 +0000718 }
719}
720
721/**
722 * __gsm_data_queue - queue a UI or UIH frame
723 * @dlci: DLCI sending the data
724 * @msg: message queued
725 *
726 * Add data to the transmit queue and try and get stuff moving
727 * out of the mux tty if not already doing so. The Caller must hold
728 * the gsm tx lock.
729 */
730
731static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
732{
733 struct gsm_mux *gsm = dlci->gsm;
734 u8 *dp = msg->data;
735 u8 *fcs = dp + msg->len;
736
737 /* Fill in the header */
738 if (gsm->encoding == 0) {
739 if (msg->len < 128)
740 *--dp = (msg->len << 1) | EA;
741 else {
Ken Millsbe7a7412010-12-13 15:27:27 +0000742 *--dp = (msg->len >> 7); /* bits 7 - 15 */
743 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */
Alan Coxe1eaea42010-03-26 11:32:54 +0000744 }
745 }
746
747 *--dp = msg->ctrl;
748 if (gsm->initiator)
749 *--dp = (msg->addr << 2) | 2 | EA;
750 else
751 *--dp = (msg->addr << 2) | EA;
752 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp);
753 /* Ugly protocol layering violation */
754 if (msg->ctrl == UI || msg->ctrl == (UI|PF))
755 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len);
756 *fcs = 0xFF - *fcs;
757
758 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl,
759 msg->data, msg->len);
760
761 /* Move the header back and adjust the length, also allow for the FCS
762 now tacked on the end */
763 msg->len += (msg->data - dp) + 1;
764 msg->data = dp;
765
766 /* Add to the actual output queue */
Russ Gorbyb4338e12012-08-13 13:44:59 +0100767 list_add_tail(&msg->list, &gsm->tx_list);
Alan Coxe1eaea42010-03-26 11:32:54 +0000768 gsm->tx_bytes += msg->len;
769 gsm_data_kick(gsm);
770}
771
772/**
773 * gsm_data_queue - queue a UI or UIH frame
774 * @dlci: DLCI sending the data
775 * @msg: message queued
776 *
777 * Add data to the transmit queue and try and get stuff moving
778 * out of the mux tty if not already doing so. Take the
779 * the gsm tx lock and dlci lock.
780 */
781
782static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
783{
784 unsigned long flags;
785 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
786 __gsm_data_queue(dlci, msg);
787 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
788}
789
790/**
791 * gsm_dlci_data_output - try and push data out of a DLCI
792 * @gsm: mux
793 * @dlci: the DLCI to pull data from
794 *
795 * Pull data from a DLCI and send it into the transmit queue if there
796 * is data. Keep to the MRU of the mux. This path handles the usual tty
797 * interface which is a byte stream with optional modem data.
798 *
799 * Caller must hold the tx_lock of the mux.
800 */
801
802static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci)
803{
804 struct gsm_msg *msg;
805 u8 *dp;
Mikhail Kshevetskiy268e5262011-09-23 19:22:56 +0400806 int len, total_size, size;
Alan Coxe1eaea42010-03-26 11:32:54 +0000807 int h = dlci->adaption - 1;
808
Mikhail Kshevetskiy268e5262011-09-23 19:22:56 +0400809 total_size = 0;
810 while(1) {
811 len = kfifo_len(dlci->fifo);
812 if (len == 0)
813 return total_size;
Alan Coxe1eaea42010-03-26 11:32:54 +0000814
Mikhail Kshevetskiy268e5262011-09-23 19:22:56 +0400815 /* MTU/MRU count only the data bits */
816 if (len > gsm->mtu)
817 len = gsm->mtu;
Alan Coxe1eaea42010-03-26 11:32:54 +0000818
Mikhail Kshevetskiy268e5262011-09-23 19:22:56 +0400819 size = len + h;
Alan Coxe1eaea42010-03-26 11:32:54 +0000820
Mikhail Kshevetskiy268e5262011-09-23 19:22:56 +0400821 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
822 /* FIXME: need a timer or something to kick this so it can't
823 get stuck with no work outstanding and no buffer free */
824 if (msg == NULL)
825 return -ENOMEM;
826 dp = msg->data;
827 switch (dlci->adaption) {
828 case 1: /* Unstructured */
829 break;
830 case 2: /* Unstructed with modem bits. Always one byte as we never
831 send inline break data */
832 *dp++ = gsm_encode_modem(dlci);
833 break;
834 }
835 WARN_ON(kfifo_out_locked(dlci->fifo, dp , len, &dlci->lock) != len);
836 __gsm_data_queue(dlci, msg);
837 total_size += size;
Alan Coxe1eaea42010-03-26 11:32:54 +0000838 }
Alan Coxe1eaea42010-03-26 11:32:54 +0000839 /* Bytes of data we used up */
Mikhail Kshevetskiy268e5262011-09-23 19:22:56 +0400840 return total_size;
Alan Coxe1eaea42010-03-26 11:32:54 +0000841}
842
843/**
844 * gsm_dlci_data_output_framed - try and push data out of a DLCI
845 * @gsm: mux
846 * @dlci: the DLCI to pull data from
847 *
848 * Pull data from a DLCI and send it into the transmit queue if there
849 * is data. Keep to the MRU of the mux. This path handles framed data
850 * queued as skbuffs to the DLCI.
851 *
852 * Caller must hold the tx_lock of the mux.
853 */
854
855static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
856 struct gsm_dlci *dlci)
857{
858 struct gsm_msg *msg;
859 u8 *dp;
860 int len, size;
861 int last = 0, first = 0;
862 int overhead = 0;
863
864 /* One byte per frame is used for B/F flags */
865 if (dlci->adaption == 4)
866 overhead = 1;
867
868 /* dlci->skb is locked by tx_lock */
869 if (dlci->skb == NULL) {
Russ Gorby88ed2a62012-08-13 13:45:30 +0100870 dlci->skb = skb_dequeue_tail(&dlci->skb_list);
Alan Coxe1eaea42010-03-26 11:32:54 +0000871 if (dlci->skb == NULL)
872 return 0;
873 first = 1;
874 }
875 len = dlci->skb->len + overhead;
876
877 /* MTU/MRU count only the data bits */
878 if (len > gsm->mtu) {
879 if (dlci->adaption == 3) {
880 /* Over long frame, bin it */
Russ Gorby329e5672012-08-13 13:45:15 +0100881 dev_kfree_skb_any(dlci->skb);
Alan Coxe1eaea42010-03-26 11:32:54 +0000882 dlci->skb = NULL;
883 return 0;
884 }
885 len = gsm->mtu;
886 } else
887 last = 1;
888
889 size = len + overhead;
890 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
891
892 /* FIXME: need a timer or something to kick this so it can't
893 get stuck with no work outstanding and no buffer free */
Russ Gorby88ed2a62012-08-13 13:45:30 +0100894 if (msg == NULL) {
895 skb_queue_tail(&dlci->skb_list, dlci->skb);
896 dlci->skb = NULL;
Alan Coxe1eaea42010-03-26 11:32:54 +0000897 return -ENOMEM;
Russ Gorby88ed2a62012-08-13 13:45:30 +0100898 }
Alan Coxe1eaea42010-03-26 11:32:54 +0000899 dp = msg->data;
900
901 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */
902 /* Flag byte to carry the start/end info */
903 *dp++ = last << 7 | first << 6 | 1; /* EA */
904 len--;
905 }
Russ Gorby57f21042011-06-14 13:23:29 -0700906 memcpy(dp, dlci->skb->data, len);
907 skb_pull(dlci->skb, len);
Alan Coxe1eaea42010-03-26 11:32:54 +0000908 __gsm_data_queue(dlci, msg);
Russ Gorbybcd5abe2011-06-16 14:20:12 -0700909 if (last) {
Russ Gorby329e5672012-08-13 13:45:15 +0100910 dev_kfree_skb_any(dlci->skb);
Alan Coxe1eaea42010-03-26 11:32:54 +0000911 dlci->skb = NULL;
Russ Gorbybcd5abe2011-06-16 14:20:12 -0700912 }
Alan Coxe1eaea42010-03-26 11:32:54 +0000913 return size;
914}
915
916/**
917 * gsm_dlci_data_sweep - look for data to send
918 * @gsm: the GSM mux
919 *
920 * Sweep the GSM mux channels in priority order looking for ones with
921 * data to send. We could do with optimising this scan a bit. We aim
922 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit
923 * TX_THRESH_LO we get called again
924 *
925 * FIXME: We should round robin between groups and in theory you can
926 * renegotiate DLCI priorities with optional stuff. Needs optimising.
927 */
928
929static void gsm_dlci_data_sweep(struct gsm_mux *gsm)
930{
931 int len;
932 /* Priority ordering: We should do priority with RR of the groups */
933 int i = 1;
Alan Coxe1eaea42010-03-26 11:32:54 +0000934
Alan Coxe1eaea42010-03-26 11:32:54 +0000935 while (i < NUM_DLCI) {
936 struct gsm_dlci *dlci;
937
938 if (gsm->tx_bytes > TX_THRESH_HI)
939 break;
940 dlci = gsm->dlci[i];
941 if (dlci == NULL || dlci->constipated) {
942 i++;
943 continue;
944 }
Russ Gorbybcd5abe2011-06-16 14:20:12 -0700945 if (dlci->adaption < 3 && !dlci->net)
Alan Coxe1eaea42010-03-26 11:32:54 +0000946 len = gsm_dlci_data_output(gsm, dlci);
947 else
948 len = gsm_dlci_data_output_framed(gsm, dlci);
949 if (len < 0)
Julia Lawalle73790a2010-08-10 18:03:12 -0700950 break;
Alan Coxe1eaea42010-03-26 11:32:54 +0000951 /* DLCI empty - try the next */
952 if (len == 0)
953 i++;
954 }
Alan Coxe1eaea42010-03-26 11:32:54 +0000955}
956
957/**
958 * gsm_dlci_data_kick - transmit if possible
959 * @dlci: DLCI to kick
960 *
961 * Transmit data from this DLCI if the queue is empty. We can't rely on
962 * a tty wakeup except when we filled the pipe so we need to fire off
963 * new data ourselves in other cases.
964 */
965
966static void gsm_dlci_data_kick(struct gsm_dlci *dlci)
967{
968 unsigned long flags;
Russ Gorby192b6042012-08-13 13:43:36 +0100969 int sweep;
Alan Coxe1eaea42010-03-26 11:32:54 +0000970
samix.lebsir10c6c382012-08-13 13:44:22 +0100971 if (dlci->constipated)
Frederic Beratc01af4f2012-08-13 13:43:58 +0100972 return;
Frederic Beratc01af4f2012-08-13 13:43:58 +0100973
Alan Coxe1eaea42010-03-26 11:32:54 +0000974 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
975 /* If we have nothing running then we need to fire up */
Russ Gorby192b6042012-08-13 13:43:36 +0100976 sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO);
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);
Russ Gorby192b6042012-08-13 13:43:36 +0100982 }
983 if (sweep)
984 gsm_dlci_data_sweep(dlci->gsm);
Alan Coxe1eaea42010-03-26 11:32:54 +0000985 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
986}
987
988/*
989 * Control message processing
990 */
991
992
993/**
994 * gsm_control_reply - send a response frame to a control
995 * @gsm: gsm channel
996 * @cmd: the command to use
997 * @data: data to follow encoded info
998 * @dlen: length of data
999 *
1000 * Encode up and queue a UI/UIH frame containing our response.
1001 */
1002
1003static void gsm_control_reply(struct gsm_mux *gsm, int cmd, u8 *data,
1004 int dlen)
1005{
1006 struct gsm_msg *msg;
1007 msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype);
Ken Mills093d8042010-12-13 15:28:03 +00001008 if (msg == NULL)
1009 return;
Alan Coxe1eaea42010-03-26 11:32:54 +00001010 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */
1011 msg->data[1] = (dlen << 1) | EA;
1012 memcpy(msg->data + 2, data, dlen);
1013 gsm_data_queue(gsm->dlci[0], msg);
1014}
1015
1016/**
1017 * gsm_process_modem - process received modem status
1018 * @tty: virtual tty bound to the DLCI
1019 * @dlci: DLCI to affect
1020 * @modem: modem bits (full EA)
1021 *
1022 * Used when a modem control message or line state inline in adaption
1023 * layer 2 is processed. Sort out the local modem state and throttles
1024 */
1025
1026static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
Russ Gorby72632872011-06-14 13:23:28 -07001027 u32 modem, int clen)
Alan Coxe1eaea42010-03-26 11:32:54 +00001028{
1029 int mlines = 0;
Russ Gorby72632872011-06-14 13:23:28 -07001030 u8 brk = 0;
Frederic Beratc01af4f2012-08-13 13:43:58 +01001031 int fc;
Russ Gorby72632872011-06-14 13:23:28 -07001032
1033 /* The modem status command can either contain one octet (v.24 signals)
1034 or two octets (v.24 signals + break signals). The length field will
1035 either be 2 or 3 respectively. This is specified in section
1036 5.4.6.3.7 of the 27.010 mux spec. */
1037
1038 if (clen == 2)
1039 modem = modem & 0x7f;
1040 else {
1041 brk = modem & 0x7f;
1042 modem = (modem >> 7) & 0x7f;
Frederic Beratc01af4f2012-08-13 13:43:58 +01001043 }
Alan Coxe1eaea42010-03-26 11:32:54 +00001044
1045 /* Flow control/ready to communicate */
Frederic Beratc01af4f2012-08-13 13:43:58 +01001046 fc = (modem & MDM_FC) || !(modem & MDM_RTR);
1047 if (fc && !dlci->constipated) {
Alan Coxe1eaea42010-03-26 11:32:54 +00001048 /* Need to throttle our output on this device */
1049 dlci->constipated = 1;
Frederic Beratc01af4f2012-08-13 13:43:58 +01001050 } else if (!fc && dlci->constipated) {
Alan Coxe1eaea42010-03-26 11:32:54 +00001051 dlci->constipated = 0;
1052 gsm_dlci_data_kick(dlci);
1053 }
Frederic Beratc01af4f2012-08-13 13:43:58 +01001054
Alan Coxe1eaea42010-03-26 11:32:54 +00001055 /* Map modem bits */
Frederic Beratc01af4f2012-08-13 13:43:58 +01001056 if (modem & MDM_RTC)
1057 mlines |= TIOCM_DSR | TIOCM_DTR;
Alan Coxe1eaea42010-03-26 11:32:54 +00001058 if (modem & MDM_RTR)
1059 mlines |= TIOCM_RTS | TIOCM_CTS;
1060 if (modem & MDM_IC)
1061 mlines |= TIOCM_RI;
1062 if (modem & MDM_DV)
1063 mlines |= TIOCM_CD;
1064
1065 /* Carrier drop -> hangup */
1066 if (tty) {
1067 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD))
Alan Coxadc8d742012-07-14 15:31:47 +01001068 if (!(tty->termios.c_cflag & CLOCAL))
Alan Coxe1eaea42010-03-26 11:32:54 +00001069 tty_hangup(tty);
Alan Coxe1eaea42010-03-26 11:32:54 +00001070 }
Jiri Slaby92a19f92013-01-03 15:53:03 +01001071 if (brk & 0x01)
1072 tty_insert_flip_char(&dlci->port, 0, TTY_BREAK);
Alan Coxe1eaea42010-03-26 11:32:54 +00001073 dlci->modem_rx = mlines;
1074}
1075
1076/**
1077 * gsm_control_modem - modem status received
1078 * @gsm: GSM channel
1079 * @data: data following command
1080 * @clen: command length
1081 *
1082 * We have received a modem status control message. This is used by
1083 * the GSM mux protocol to pass virtual modem line status and optionally
1084 * to indicate break signals. Unpack it, convert to Linux representation
1085 * and if need be stuff a break message down the tty.
1086 */
1087
1088static void gsm_control_modem(struct gsm_mux *gsm, u8 *data, int clen)
1089{
1090 unsigned int addr = 0;
1091 unsigned int modem = 0;
1092 struct gsm_dlci *dlci;
1093 int len = clen;
1094 u8 *dp = data;
1095 struct tty_struct *tty;
1096
1097 while (gsm_read_ea(&addr, *dp++) == 0) {
1098 len--;
1099 if (len == 0)
1100 return;
1101 }
1102 /* Must be at least one byte following the EA */
1103 len--;
1104 if (len <= 0)
1105 return;
1106
1107 addr >>= 1;
1108 /* Closed port, or invalid ? */
1109 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1110 return;
1111 dlci = gsm->dlci[addr];
1112
1113 while (gsm_read_ea(&modem, *dp++) == 0) {
1114 len--;
1115 if (len == 0)
1116 return;
1117 }
1118 tty = tty_port_tty_get(&dlci->port);
Russ Gorby72632872011-06-14 13:23:28 -07001119 gsm_process_modem(tty, dlci, modem, clen);
Alan Coxe1eaea42010-03-26 11:32:54 +00001120 if (tty) {
1121 tty_wakeup(tty);
1122 tty_kref_put(tty);
1123 }
1124 gsm_control_reply(gsm, CMD_MSC, data, clen);
1125}
1126
1127/**
1128 * gsm_control_rls - remote line status
1129 * @gsm: GSM channel
1130 * @data: data bytes
1131 * @clen: data length
1132 *
1133 * The modem sends us a two byte message on the control channel whenever
1134 * it wishes to send us an error state from the virtual link. Stuff
1135 * this into the uplink tty if present
1136 */
1137
1138static void gsm_control_rls(struct gsm_mux *gsm, u8 *data, int clen)
1139{
Jiri Slaby92a19f92013-01-03 15:53:03 +01001140 struct tty_port *port;
Alan Coxe1eaea42010-03-26 11:32:54 +00001141 unsigned int addr = 0 ;
1142 u8 bits;
1143 int len = clen;
1144 u8 *dp = data;
1145
1146 while (gsm_read_ea(&addr, *dp++) == 0) {
1147 len--;
1148 if (len == 0)
1149 return;
1150 }
1151 /* Must be at least one byte following ea */
1152 len--;
1153 if (len <= 0)
1154 return;
1155 addr >>= 1;
1156 /* Closed port, or invalid ? */
1157 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1158 return;
1159 /* No error ? */
1160 bits = *dp;
1161 if ((bits & 1) == 0)
1162 return;
Alan Coxe1eaea42010-03-26 11:32:54 +00001163
Jiri Slaby92a19f92013-01-03 15:53:03 +01001164 port = &gsm->dlci[addr]->port;
1165
1166 if (bits & 2)
1167 tty_insert_flip_char(port, 0, TTY_OVERRUN);
1168 if (bits & 4)
1169 tty_insert_flip_char(port, 0, TTY_PARITY);
1170 if (bits & 8)
1171 tty_insert_flip_char(port, 0, TTY_FRAME);
1172
Jiri Slaby2e124b42013-01-03 15:53:06 +01001173 tty_flip_buffer_push(port);
1174
Alan Coxe1eaea42010-03-26 11:32:54 +00001175 gsm_control_reply(gsm, CMD_RLS, data, clen);
1176}
1177
1178static void gsm_dlci_begin_close(struct gsm_dlci *dlci);
1179
1180/**
1181 * gsm_control_message - DLCI 0 control processing
1182 * @gsm: our GSM mux
1183 * @command: the command EA
1184 * @data: data beyond the command/length EAs
1185 * @clen: length
1186 *
1187 * Input processor for control messages from the other end of the link.
1188 * Processes the incoming request and queues a response frame or an
1189 * NSC response if not supported
1190 */
1191
1192static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
1193 u8 *data, int clen)
1194{
1195 u8 buf[1];
Russ Gorby5e447082012-08-13 13:44:40 +01001196 unsigned long flags;
1197
Alan Coxe1eaea42010-03-26 11:32:54 +00001198 switch (command) {
1199 case CMD_CLD: {
1200 struct gsm_dlci *dlci = gsm->dlci[0];
1201 /* Modem wishes to close down */
1202 if (dlci) {
1203 dlci->dead = 1;
1204 gsm->dead = 1;
1205 gsm_dlci_begin_close(dlci);
1206 }
1207 }
1208 break;
1209 case CMD_TEST:
1210 /* Modem wishes to test, reply with the data */
1211 gsm_control_reply(gsm, CMD_TEST, data, clen);
1212 break;
1213 case CMD_FCON:
Alan Coxe1eaea42010-03-26 11:32:54 +00001214 /* Modem can accept data again */
1215 gsm->constipated = 0;
Frederic Beratc01af4f2012-08-13 13:43:58 +01001216 gsm_control_reply(gsm, CMD_FCON, NULL, 0);
Alan Coxe1eaea42010-03-26 11:32:54 +00001217 /* Kick the link in case it is idling */
Russ Gorby5e447082012-08-13 13:44:40 +01001218 spin_lock_irqsave(&gsm->tx_lock, flags);
Alan Coxe1eaea42010-03-26 11:32:54 +00001219 gsm_data_kick(gsm);
Russ Gorby5e447082012-08-13 13:44:40 +01001220 spin_unlock_irqrestore(&gsm->tx_lock, flags);
Alan Coxe1eaea42010-03-26 11:32:54 +00001221 break;
Frederic Beratc01af4f2012-08-13 13:43:58 +01001222 case CMD_FCOFF:
1223 /* Modem wants us to STFU */
Frederic Beratc01af4f2012-08-13 13:43:58 +01001224 gsm->constipated = 1;
1225 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0);
1226 break;
Alan Coxe1eaea42010-03-26 11:32:54 +00001227 case CMD_MSC:
1228 /* Out of band modem line change indicator for a DLCI */
1229 gsm_control_modem(gsm, data, clen);
1230 break;
1231 case CMD_RLS:
1232 /* Out of band error reception for a DLCI */
1233 gsm_control_rls(gsm, data, clen);
1234 break;
1235 case CMD_PSC:
1236 /* Modem wishes to enter power saving state */
1237 gsm_control_reply(gsm, CMD_PSC, NULL, 0);
1238 break;
1239 /* Optional unsupported commands */
1240 case CMD_PN: /* Parameter negotiation */
Lucas De Marchi25985ed2011-03-30 22:57:33 -03001241 case CMD_RPN: /* Remote port negotiation */
1242 case CMD_SNC: /* Service negotiation command */
Alan Coxe1eaea42010-03-26 11:32:54 +00001243 default:
1244 /* Reply to bad commands with an NSC */
1245 buf[0] = command;
1246 gsm_control_reply(gsm, CMD_NSC, buf, 1);
1247 break;
1248 }
1249}
1250
1251/**
1252 * gsm_control_response - process a response to our control
1253 * @gsm: our GSM mux
1254 * @command: the command (response) EA
1255 * @data: data beyond the command/length EA
1256 * @clen: length
1257 *
1258 * Process a response to an outstanding command. We only allow a single
1259 * control message in flight so this is fairly easy. All the clean up
1260 * is done by the caller, we just update the fields, flag it as done
1261 * and return
1262 */
1263
1264static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
1265 u8 *data, int clen)
1266{
1267 struct gsm_control *ctrl;
1268 unsigned long flags;
1269
1270 spin_lock_irqsave(&gsm->control_lock, flags);
1271
1272 ctrl = gsm->pending_cmd;
1273 /* Does the reply match our command */
1274 command |= 1;
1275 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) {
1276 /* Our command was replied to, kill the retry timer */
1277 del_timer(&gsm->t2_timer);
1278 gsm->pending_cmd = NULL;
1279 /* Rejected by the other end */
1280 if (command == CMD_NSC)
1281 ctrl->error = -EOPNOTSUPP;
1282 ctrl->done = 1;
1283 wake_up(&gsm->event);
1284 }
1285 spin_unlock_irqrestore(&gsm->control_lock, flags);
1286}
1287
1288/**
Alan Cox5f9a31d2010-11-04 15:17:27 +00001289 * gsm_control_transmit - send control packet
Alan Coxe1eaea42010-03-26 11:32:54 +00001290 * @gsm: gsm mux
1291 * @ctrl: frame to send
1292 *
1293 * Send out a pending control command (called under control lock)
1294 */
1295
1296static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl)
1297{
Eric Bénarded43b472011-03-09 19:24:49 +01001298 struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, gsm->ftype);
Alan Coxe1eaea42010-03-26 11:32:54 +00001299 if (msg == NULL)
1300 return;
1301 msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */
1302 memcpy(msg->data + 1, ctrl->data, ctrl->len);
1303 gsm_data_queue(gsm->dlci[0], msg);
1304}
1305
1306/**
1307 * gsm_control_retransmit - retransmit a control frame
1308 * @data: pointer to our gsm object
1309 *
1310 * Called off the T2 timer expiry in order to retransmit control frames
1311 * that have been lost in the system somewhere. The control_lock protects
1312 * us from colliding with another sender or a receive completion event.
1313 * In that situation the timer may still occur in a small window but
1314 * gsm->pending_cmd will be NULL and we just let the timer expire.
1315 */
1316
1317static void gsm_control_retransmit(unsigned long data)
1318{
1319 struct gsm_mux *gsm = (struct gsm_mux *)data;
1320 struct gsm_control *ctrl;
1321 unsigned long flags;
1322 spin_lock_irqsave(&gsm->control_lock, flags);
1323 ctrl = gsm->pending_cmd;
1324 if (ctrl) {
1325 gsm->cretries--;
1326 if (gsm->cretries == 0) {
1327 gsm->pending_cmd = NULL;
1328 ctrl->error = -ETIMEDOUT;
1329 ctrl->done = 1;
1330 spin_unlock_irqrestore(&gsm->control_lock, flags);
1331 wake_up(&gsm->event);
1332 return;
1333 }
1334 gsm_control_transmit(gsm, ctrl);
1335 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1336 }
1337 spin_unlock_irqrestore(&gsm->control_lock, flags);
1338}
1339
1340/**
1341 * gsm_control_send - send a control frame on DLCI 0
1342 * @gsm: the GSM channel
1343 * @command: command to send including CR bit
1344 * @data: bytes of data (must be kmalloced)
1345 * @len: length of the block to send
1346 *
1347 * Queue and dispatch a control command. Only one command can be
1348 * active at a time. In theory more can be outstanding but the matching
1349 * gets really complicated so for now stick to one outstanding.
1350 */
1351
1352static struct gsm_control *gsm_control_send(struct gsm_mux *gsm,
1353 unsigned int command, u8 *data, int clen)
1354{
1355 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control),
1356 GFP_KERNEL);
1357 unsigned long flags;
1358 if (ctrl == NULL)
1359 return NULL;
1360retry:
1361 wait_event(gsm->event, gsm->pending_cmd == NULL);
1362 spin_lock_irqsave(&gsm->control_lock, flags);
1363 if (gsm->pending_cmd != NULL) {
1364 spin_unlock_irqrestore(&gsm->control_lock, flags);
1365 goto retry;
1366 }
1367 ctrl->cmd = command;
1368 ctrl->data = data;
1369 ctrl->len = clen;
1370 gsm->pending_cmd = ctrl;
1371 gsm->cretries = gsm->n2;
1372 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1373 gsm_control_transmit(gsm, ctrl);
1374 spin_unlock_irqrestore(&gsm->control_lock, flags);
1375 return ctrl;
1376}
1377
1378/**
1379 * gsm_control_wait - wait for a control to finish
1380 * @gsm: GSM mux
1381 * @control: control we are waiting on
1382 *
1383 * Waits for the control to complete or time out. Frees any used
1384 * resources and returns 0 for success, or an error if the remote
1385 * rejected or ignored the request.
1386 */
1387
1388static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
1389{
1390 int err;
1391 wait_event(gsm->event, control->done == 1);
1392 err = control->error;
1393 kfree(control);
1394 return err;
1395}
1396
1397
1398/*
1399 * DLCI level handling: Needs krefs
1400 */
1401
1402/*
1403 * State transitions and timers
1404 */
1405
1406/**
1407 * gsm_dlci_close - a DLCI has closed
1408 * @dlci: DLCI that closed
1409 *
1410 * Perform processing when moving a DLCI into closed state. If there
1411 * is an attached tty this is hung up
1412 */
1413
1414static void gsm_dlci_close(struct gsm_dlci *dlci)
1415{
1416 del_timer(&dlci->t1);
1417 if (debug & 8)
Alan Cox5f9a31d2010-11-04 15:17:27 +00001418 pr_debug("DLCI %d goes closed.\n", dlci->addr);
Alan Coxe1eaea42010-03-26 11:32:54 +00001419 dlci->state = DLCI_CLOSED;
1420 if (dlci->addr != 0) {
Jiri Slabyaa27a092013-03-07 13:12:30 +01001421 tty_port_tty_hangup(&dlci->port, false);
Alan Coxe1eaea42010-03-26 11:32:54 +00001422 kfifo_reset(dlci->fifo);
1423 } else
1424 dlci->gsm->dead = 1;
1425 wake_up(&dlci->gsm->event);
1426 /* A DLCI 0 close is a MUX termination so we need to kick that
1427 back to userspace somehow */
1428}
1429
1430/**
1431 * gsm_dlci_open - a DLCI has opened
1432 * @dlci: DLCI that opened
1433 *
1434 * Perform processing when moving a DLCI into open state.
1435 */
1436
1437static void gsm_dlci_open(struct gsm_dlci *dlci)
1438{
1439 /* Note that SABM UA .. SABM UA first UA lost can mean that we go
1440 open -> open */
1441 del_timer(&dlci->t1);
1442 /* This will let a tty open continue */
1443 dlci->state = DLCI_OPEN;
1444 if (debug & 8)
Alan Cox5f9a31d2010-11-04 15:17:27 +00001445 pr_debug("DLCI %d goes open.\n", dlci->addr);
Alan Coxe1eaea42010-03-26 11:32:54 +00001446 wake_up(&dlci->gsm->event);
1447}
1448
1449/**
1450 * gsm_dlci_t1 - T1 timer expiry
1451 * @dlci: DLCI that opened
1452 *
1453 * The T1 timer handles retransmits of control frames (essentially of
1454 * SABM and DISC). We resend the command until the retry count runs out
1455 * in which case an opening port goes back to closed and a closing port
1456 * is simply put into closed state (any further frames from the other
1457 * end will get a DM response)
1458 */
1459
1460static void gsm_dlci_t1(unsigned long data)
1461{
1462 struct gsm_dlci *dlci = (struct gsm_dlci *)data;
1463 struct gsm_mux *gsm = dlci->gsm;
1464
1465 switch (dlci->state) {
1466 case DLCI_OPENING:
1467 dlci->retries--;
1468 if (dlci->retries) {
1469 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1470 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1471 } else
1472 gsm_dlci_close(dlci);
1473 break;
1474 case DLCI_CLOSING:
1475 dlci->retries--;
1476 if (dlci->retries) {
1477 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1478 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1479 } else
1480 gsm_dlci_close(dlci);
1481 break;
1482 }
1483}
1484
1485/**
1486 * gsm_dlci_begin_open - start channel open procedure
1487 * @dlci: DLCI to open
1488 *
1489 * Commence opening a DLCI from the Linux side. We issue SABM messages
1490 * to the modem which should then reply with a UA, at which point we
1491 * will move into open state. Opening is done asynchronously with retry
1492 * running off timers and the responses.
1493 */
1494
1495static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
1496{
1497 struct gsm_mux *gsm = dlci->gsm;
1498 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING)
1499 return;
1500 dlci->retries = gsm->n2;
1501 dlci->state = DLCI_OPENING;
1502 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1503 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1504}
1505
1506/**
1507 * gsm_dlci_begin_close - start channel open procedure
1508 * @dlci: DLCI to open
1509 *
1510 * Commence closing a DLCI from the Linux side. We issue DISC messages
1511 * to the modem which should then reply with a UA, at which point we
1512 * will move into closed state. Closing is done asynchronously with retry
1513 * off timers. We may also receive a DM reply from the other end which
1514 * indicates the channel was already closed.
1515 */
1516
1517static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
1518{
1519 struct gsm_mux *gsm = dlci->gsm;
1520 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
1521 return;
1522 dlci->retries = gsm->n2;
1523 dlci->state = DLCI_CLOSING;
1524 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1525 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1526}
1527
1528/**
1529 * gsm_dlci_data - data arrived
1530 * @dlci: channel
1531 * @data: block of bytes received
1532 * @len: length of received block
1533 *
1534 * A UI or UIH frame has arrived which contains data for a channel
1535 * other than the control channel. If the relevant virtual tty is
1536 * open we shovel the bits down it, if not we drop them.
1537 */
1538
Russ Gorby72632872011-06-14 13:23:28 -07001539static void gsm_dlci_data(struct gsm_dlci *dlci, u8 *data, int clen)
Alan Coxe1eaea42010-03-26 11:32:54 +00001540{
1541 /* krefs .. */
1542 struct tty_port *port = &dlci->port;
Jiri Slaby2e124b42013-01-03 15:53:06 +01001543 struct tty_struct *tty;
Alan Coxe1eaea42010-03-26 11:32:54 +00001544 unsigned int modem = 0;
Russ Gorby72632872011-06-14 13:23:28 -07001545 int len = clen;
Alan Coxe1eaea42010-03-26 11:32:54 +00001546
1547 if (debug & 16)
Jiri Slaby2e124b42013-01-03 15:53:06 +01001548 pr_debug("%d bytes for tty\n", len);
1549 switch (dlci->adaption) {
1550 /* Unsupported types */
1551 /* Packetised interruptible data */
1552 case 4:
1553 break;
1554 /* Packetised uininterruptible voice/data */
1555 case 3:
1556 break;
1557 /* Asynchronous serial with line state in each frame */
1558 case 2:
1559 while (gsm_read_ea(&modem, *data++) == 0) {
1560 len--;
1561 if (len == 0)
1562 return;
Alan Coxe1eaea42010-03-26 11:32:54 +00001563 }
Jiri Slaby2e124b42013-01-03 15:53:06 +01001564 tty = tty_port_tty_get(port);
1565 if (tty) {
1566 gsm_process_modem(tty, dlci, modem, clen);
1567 tty_kref_put(tty);
1568 }
1569 /* Line state will go via DLCI 0 controls only */
1570 case 1:
1571 default:
1572 tty_insert_flip_string(port, data, len);
1573 tty_flip_buffer_push(port);
Alan Coxe1eaea42010-03-26 11:32:54 +00001574 }
1575}
1576
1577/**
1578 * gsm_dlci_control - data arrived on control channel
1579 * @dlci: channel
1580 * @data: block of bytes received
1581 * @len: length of received block
1582 *
1583 * A UI or UIH frame has arrived which contains data for DLCI 0 the
1584 * control channel. This should contain a command EA followed by
1585 * control data bytes. The command EA contains a command/response bit
1586 * and we divide up the work accordingly.
1587 */
1588
1589static void gsm_dlci_command(struct gsm_dlci *dlci, u8 *data, int len)
1590{
1591 /* See what command is involved */
1592 unsigned int command = 0;
1593 while (len-- > 0) {
1594 if (gsm_read_ea(&command, *data++) == 1) {
1595 int clen = *data++;
1596 len--;
1597 /* FIXME: this is properly an EA */
1598 clen >>= 1;
1599 /* Malformed command ? */
1600 if (clen > len)
1601 return;
1602 if (command & 1)
1603 gsm_control_message(dlci->gsm, command,
1604 data, clen);
1605 else
1606 gsm_control_response(dlci->gsm, command,
1607 data, clen);
1608 return;
1609 }
1610 }
1611}
1612
1613/*
1614 * Allocate/Free DLCI channels
1615 */
1616
1617/**
1618 * gsm_dlci_alloc - allocate a DLCI
1619 * @gsm: GSM mux
1620 * @addr: address of the DLCI
1621 *
1622 * Allocate and install a new DLCI object into the GSM mux.
1623 *
1624 * FIXME: review locking races
1625 */
1626
1627static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
1628{
1629 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC);
1630 if (dlci == NULL)
1631 return NULL;
1632 spin_lock_init(&dlci->lock);
Russ Gorbybcd5abe2011-06-16 14:20:12 -07001633 mutex_init(&dlci->mutex);
Alan Coxe1eaea42010-03-26 11:32:54 +00001634 dlci->fifo = &dlci->_fifo;
1635 if (kfifo_alloc(&dlci->_fifo, 4096, GFP_KERNEL) < 0) {
1636 kfree(dlci);
1637 return NULL;
1638 }
1639
1640 skb_queue_head_init(&dlci->skb_list);
1641 init_timer(&dlci->t1);
1642 dlci->t1.function = gsm_dlci_t1;
1643 dlci->t1.data = (unsigned long)dlci;
1644 tty_port_init(&dlci->port);
1645 dlci->port.ops = &gsm_port_ops;
1646 dlci->gsm = gsm;
1647 dlci->addr = addr;
1648 dlci->adaption = gsm->adaption;
1649 dlci->state = DLCI_CLOSED;
1650 if (addr)
1651 dlci->data = gsm_dlci_data;
1652 else
1653 dlci->data = gsm_dlci_command;
1654 gsm->dlci[addr] = dlci;
1655 return dlci;
1656}
1657
1658/**
Russ Gorby6ab8fba2011-06-16 14:20:13 -07001659 * gsm_dlci_free - free DLCI
1660 * @dlci: DLCI to free
Alan Coxe1eaea42010-03-26 11:32:54 +00001661 *
Russ Gorby6ab8fba2011-06-16 14:20:13 -07001662 * Free up a DLCI.
Alan Coxe1eaea42010-03-26 11:32:54 +00001663 *
1664 * Can sleep.
1665 */
Jiri Slaby9a8e62b2012-11-15 09:49:53 +01001666static void gsm_dlci_free(struct tty_port *port)
Russ Gorby6ab8fba2011-06-16 14:20:13 -07001667{
Jiri Slaby9a8e62b2012-11-15 09:49:53 +01001668 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
Russ Gorby6ab8fba2011-06-16 14:20:13 -07001669
1670 del_timer_sync(&dlci->t1);
1671 dlci->gsm->dlci[dlci->addr] = NULL;
1672 kfifo_free(dlci->fifo);
1673 while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
Russ Gorby329e5672012-08-13 13:45:15 +01001674 dev_kfree_skb(dlci->skb);
Russ Gorby6ab8fba2011-06-16 14:20:13 -07001675 kfree(dlci);
1676}
1677
1678static inline void dlci_get(struct gsm_dlci *dlci)
1679{
Jiri Slaby9a8e62b2012-11-15 09:49:53 +01001680 tty_port_get(&dlci->port);
Russ Gorby6ab8fba2011-06-16 14:20:13 -07001681}
1682
1683static inline void dlci_put(struct gsm_dlci *dlci)
1684{
Jiri Slaby9a8e62b2012-11-15 09:49:53 +01001685 tty_port_put(&dlci->port);
Russ Gorby6ab8fba2011-06-16 14:20:13 -07001686}
1687
Dirkjan Bussink4d9b1092013-01-30 11:44:50 +01001688static void gsm_destroy_network(struct gsm_dlci *dlci);
1689
Russ Gorby6ab8fba2011-06-16 14:20:13 -07001690/**
1691 * gsm_dlci_release - release DLCI
1692 * @dlci: DLCI to destroy
1693 *
1694 * Release a DLCI. Actual free is deferred until either
1695 * mux is closed or tty is closed - whichever is last.
1696 *
1697 * Can sleep.
1698 */
1699static void gsm_dlci_release(struct gsm_dlci *dlci)
Alan Coxe1eaea42010-03-26 11:32:54 +00001700{
1701 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1702 if (tty) {
Dirkjan Bussink4d9b1092013-01-30 11:44:50 +01001703 mutex_lock(&dlci->mutex);
1704 gsm_destroy_network(dlci);
1705 mutex_unlock(&dlci->mutex);
1706
1707 /* tty_vhangup needs the tty_lock, so unlock and
1708 relock after doing the hangup. */
1709 tty_unlock(tty);
Alan Coxe1eaea42010-03-26 11:32:54 +00001710 tty_vhangup(tty);
Dirkjan Bussink4d9b1092013-01-30 11:44:50 +01001711 tty_lock(tty);
1712 tty_port_tty_set(&dlci->port, NULL);
Alan Coxe1eaea42010-03-26 11:32:54 +00001713 tty_kref_put(tty);
1714 }
Dirkjan Bussink4d9b1092013-01-30 11:44:50 +01001715 dlci->state = DLCI_CLOSED;
Russ Gorby6ab8fba2011-06-16 14:20:13 -07001716 dlci_put(dlci);
Alan Coxe1eaea42010-03-26 11:32:54 +00001717}
1718
Alan Coxe1eaea42010-03-26 11:32:54 +00001719/*
1720 * LAPBish link layer logic
1721 */
1722
1723/**
1724 * gsm_queue - a GSM frame is ready to process
1725 * @gsm: pointer to our gsm mux
1726 *
1727 * At this point in time a frame has arrived and been demangled from
1728 * the line encoding. All the differences between the encodings have
1729 * been handled below us and the frame is unpacked into the structures.
1730 * The fcs holds the header FCS but any data FCS must be added here.
1731 */
1732
1733static void gsm_queue(struct gsm_mux *gsm)
1734{
1735 struct gsm_dlci *dlci;
1736 u8 cr;
1737 int address;
1738 /* We have to sneak a look at the packet body to do the FCS.
1739 A somewhat layering violation in the spec */
1740
1741 if ((gsm->control & ~PF) == UI)
1742 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len);
Mikhail Kshevetskiy9db4e432011-03-27 04:05:00 +04001743 if (gsm->encoding == 0){
1744 /* WARNING: gsm->received_fcs is used for gsm->encoding = 0 only.
1745 In this case it contain the last piece of data
1746 required to generate final CRC */
1747 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs);
1748 }
Alan Coxe1eaea42010-03-26 11:32:54 +00001749 if (gsm->fcs != GOOD_FCS) {
1750 gsm->bad_fcs++;
1751 if (debug & 4)
Alan Cox5f9a31d2010-11-04 15:17:27 +00001752 pr_debug("BAD FCS %02x\n", gsm->fcs);
Alan Coxe1eaea42010-03-26 11:32:54 +00001753 return;
1754 }
1755 address = gsm->address >> 1;
1756 if (address >= NUM_DLCI)
1757 goto invalid;
1758
1759 cr = gsm->address & 1; /* C/R bit */
1760
1761 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
1762
1763 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */
1764 dlci = gsm->dlci[address];
1765
1766 switch (gsm->control) {
1767 case SABM|PF:
1768 if (cr == 0)
1769 goto invalid;
1770 if (dlci == NULL)
1771 dlci = gsm_dlci_alloc(gsm, address);
1772 if (dlci == NULL)
1773 return;
1774 if (dlci->dead)
1775 gsm_response(gsm, address, DM);
1776 else {
1777 gsm_response(gsm, address, UA);
1778 gsm_dlci_open(dlci);
1779 }
1780 break;
1781 case DISC|PF:
1782 if (cr == 0)
1783 goto invalid;
1784 if (dlci == NULL || dlci->state == DLCI_CLOSED) {
1785 gsm_response(gsm, address, DM);
1786 return;
1787 }
1788 /* Real close complete */
1789 gsm_response(gsm, address, UA);
1790 gsm_dlci_close(dlci);
1791 break;
1792 case UA:
1793 case UA|PF:
1794 if (cr == 0 || dlci == NULL)
1795 break;
1796 switch (dlci->state) {
1797 case DLCI_CLOSING:
1798 gsm_dlci_close(dlci);
1799 break;
1800 case DLCI_OPENING:
1801 gsm_dlci_open(dlci);
1802 break;
1803 }
1804 break;
1805 case DM: /* DM can be valid unsolicited */
1806 case DM|PF:
1807 if (cr)
1808 goto invalid;
1809 if (dlci == NULL)
1810 return;
1811 gsm_dlci_close(dlci);
1812 break;
1813 case UI:
1814 case UI|PF:
1815 case UIH:
1816 case UIH|PF:
1817#if 0
1818 if (cr)
1819 goto invalid;
1820#endif
1821 if (dlci == NULL || dlci->state != DLCI_OPEN) {
1822 gsm_command(gsm, address, DM|PF);
1823 return;
1824 }
1825 dlci->data(dlci, gsm->buf, gsm->len);
1826 break;
1827 default:
1828 goto invalid;
1829 }
1830 return;
1831invalid:
1832 gsm->malformed++;
1833 return;
1834}
1835
1836
1837/**
1838 * gsm0_receive - perform processing for non-transparency
1839 * @gsm: gsm data for this ldisc instance
1840 * @c: character
1841 *
1842 * Receive bytes in gsm mode 0
1843 */
1844
1845static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
1846{
Alan Coxc2f2f002010-11-04 15:17:03 +00001847 unsigned int len;
1848
Alan Coxe1eaea42010-03-26 11:32:54 +00001849 switch (gsm->state) {
1850 case GSM_SEARCH: /* SOF marker */
1851 if (c == GSM0_SOF) {
1852 gsm->state = GSM_ADDRESS;
1853 gsm->address = 0;
1854 gsm->len = 0;
1855 gsm->fcs = INIT_FCS;
1856 }
Alan Coxc2f2f002010-11-04 15:17:03 +00001857 break;
1858 case GSM_ADDRESS: /* Address EA */
Alan Coxe1eaea42010-03-26 11:32:54 +00001859 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1860 if (gsm_read_ea(&gsm->address, c))
1861 gsm->state = GSM_CONTROL;
1862 break;
1863 case GSM_CONTROL: /* Control Byte */
1864 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1865 gsm->control = c;
Alan Coxc2f2f002010-11-04 15:17:03 +00001866 gsm->state = GSM_LEN0;
Alan Coxe1eaea42010-03-26 11:32:54 +00001867 break;
Alan Coxc2f2f002010-11-04 15:17:03 +00001868 case GSM_LEN0: /* Length EA */
Alan Coxe1eaea42010-03-26 11:32:54 +00001869 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1870 if (gsm_read_ea(&gsm->len, c)) {
1871 if (gsm->len > gsm->mru) {
1872 gsm->bad_size++;
1873 gsm->state = GSM_SEARCH;
1874 break;
1875 }
1876 gsm->count = 0;
Alan Coxc2f2f002010-11-04 15:17:03 +00001877 if (!gsm->len)
1878 gsm->state = GSM_FCS;
1879 else
1880 gsm->state = GSM_DATA;
1881 break;
Alan Coxe1eaea42010-03-26 11:32:54 +00001882 }
Alan Coxc2f2f002010-11-04 15:17:03 +00001883 gsm->state = GSM_LEN1;
1884 break;
1885 case GSM_LEN1:
1886 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1887 len = c;
1888 gsm->len |= len << 7;
1889 if (gsm->len > gsm->mru) {
1890 gsm->bad_size++;
1891 gsm->state = GSM_SEARCH;
1892 break;
1893 }
1894 gsm->count = 0;
1895 if (!gsm->len)
1896 gsm->state = GSM_FCS;
1897 else
1898 gsm->state = GSM_DATA;
Alan Coxe1eaea42010-03-26 11:32:54 +00001899 break;
1900 case GSM_DATA: /* Data */
1901 gsm->buf[gsm->count++] = c;
1902 if (gsm->count == gsm->len)
1903 gsm->state = GSM_FCS;
1904 break;
1905 case GSM_FCS: /* FCS follows the packet */
Alan Coxc2f2f002010-11-04 15:17:03 +00001906 gsm->received_fcs = c;
Alan Coxe1eaea42010-03-26 11:32:54 +00001907 gsm_queue(gsm);
Alan Coxc2f2f002010-11-04 15:17:03 +00001908 gsm->state = GSM_SSOF;
1909 break;
1910 case GSM_SSOF:
1911 if (c == GSM0_SOF) {
1912 gsm->state = GSM_SEARCH;
1913 break;
1914 }
Alan Coxe1eaea42010-03-26 11:32:54 +00001915 break;
1916 }
1917}
1918
1919/**
Alan Coxc2f2f002010-11-04 15:17:03 +00001920 * gsm1_receive - perform processing for non-transparency
Alan Coxe1eaea42010-03-26 11:32:54 +00001921 * @gsm: gsm data for this ldisc instance
1922 * @c: character
1923 *
1924 * Receive bytes in mode 1 (Advanced option)
1925 */
1926
1927static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
1928{
1929 if (c == GSM1_SOF) {
1930 /* EOF is only valid in frame if we have got to the data state
1931 and received at least one byte (the FCS) */
1932 if (gsm->state == GSM_DATA && gsm->count) {
1933 /* Extract the FCS */
1934 gsm->count--;
1935 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
1936 gsm->len = gsm->count;
1937 gsm_queue(gsm);
1938 gsm->state = GSM_START;
1939 return;
1940 }
1941 /* Any partial frame was a runt so go back to start */
1942 if (gsm->state != GSM_START) {
1943 gsm->malformed++;
1944 gsm->state = GSM_START;
1945 }
1946 /* A SOF in GSM_START means we are still reading idling or
1947 framing bytes */
1948 return;
1949 }
1950
1951 if (c == GSM1_ESCAPE) {
1952 gsm->escape = 1;
1953 return;
1954 }
1955
1956 /* Only an unescaped SOF gets us out of GSM search */
1957 if (gsm->state == GSM_SEARCH)
1958 return;
1959
1960 if (gsm->escape) {
1961 c ^= GSM1_ESCAPE_BITS;
1962 gsm->escape = 0;
1963 }
1964 switch (gsm->state) {
1965 case GSM_START: /* First byte after SOF */
1966 gsm->address = 0;
1967 gsm->state = GSM_ADDRESS;
1968 gsm->fcs = INIT_FCS;
1969 /* Drop through */
1970 case GSM_ADDRESS: /* Address continuation */
1971 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1972 if (gsm_read_ea(&gsm->address, c))
1973 gsm->state = GSM_CONTROL;
1974 break;
1975 case GSM_CONTROL: /* Control Byte */
1976 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1977 gsm->control = c;
1978 gsm->count = 0;
1979 gsm->state = GSM_DATA;
1980 break;
1981 case GSM_DATA: /* Data */
Alan Cox5f9a31d2010-11-04 15:17:27 +00001982 if (gsm->count > gsm->mru) { /* Allow one for the FCS */
Alan Coxe1eaea42010-03-26 11:32:54 +00001983 gsm->state = GSM_OVERRUN;
1984 gsm->bad_size++;
1985 } else
1986 gsm->buf[gsm->count++] = c;
1987 break;
1988 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */
1989 break;
1990 }
1991}
1992
1993/**
1994 * gsm_error - handle tty error
1995 * @gsm: ldisc data
1996 * @data: byte received (may be invalid)
1997 * @flag: error received
1998 *
1999 * Handle an error in the receipt of data for a frame. Currently we just
2000 * go back to hunting for a SOF.
2001 *
2002 * FIXME: better diagnostics ?
2003 */
2004
2005static void gsm_error(struct gsm_mux *gsm,
2006 unsigned char data, unsigned char flag)
2007{
2008 gsm->state = GSM_SEARCH;
2009 gsm->io_error++;
2010}
2011
2012/**
2013 * gsm_cleanup_mux - generic GSM protocol cleanup
2014 * @gsm: our mux
2015 *
2016 * Clean up the bits of the mux which are the same for all framing
2017 * protocols. Remove the mux from the mux table, stop all the timers
2018 * and then shut down each device hanging up the channels as we go.
2019 */
2020
2021void gsm_cleanup_mux(struct gsm_mux *gsm)
2022{
2023 int i;
2024 struct gsm_dlci *dlci = gsm->dlci[0];
Russ Gorby329e5672012-08-13 13:45:15 +01002025 struct gsm_msg *txq, *ntxq;
Alan Coxf17141f2011-08-26 11:28:11 +01002026 struct gsm_control *gc;
Alan Coxe1eaea42010-03-26 11:32:54 +00002027
2028 gsm->dead = 1;
2029
2030 spin_lock(&gsm_mux_lock);
2031 for (i = 0; i < MAX_MUX; i++) {
2032 if (gsm_mux[i] == gsm) {
2033 gsm_mux[i] = NULL;
2034 break;
2035 }
2036 }
2037 spin_unlock(&gsm_mux_lock);
2038 WARN_ON(i == MAX_MUX);
2039
Alan Coxf17141f2011-08-26 11:28:11 +01002040 /* In theory disconnecting DLCI 0 is sufficient but for some
2041 modems this is apparently not the case. */
2042 if (dlci) {
2043 gc = gsm_control_send(gsm, CMD_CLD, NULL, 0);
2044 if (gc)
2045 gsm_control_wait(gsm, gc);
2046 }
Alan Coxe1eaea42010-03-26 11:32:54 +00002047 del_timer_sync(&gsm->t2_timer);
2048 /* Now we are sure T2 has stopped */
2049 if (dlci) {
2050 dlci->dead = 1;
2051 gsm_dlci_begin_close(dlci);
2052 wait_event_interruptible(gsm->event,
2053 dlci->state == DLCI_CLOSED);
2054 }
2055 /* Free up any link layer users */
2056 for (i = 0; i < NUM_DLCI; i++)
2057 if (gsm->dlci[i])
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002058 gsm_dlci_release(gsm->dlci[i]);
Alan Coxe1eaea42010-03-26 11:32:54 +00002059 /* Now wipe the queues */
Russ Gorbyb4338e12012-08-13 13:44:59 +01002060 list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list)
Alan Coxe1eaea42010-03-26 11:32:54 +00002061 kfree(txq);
Russ Gorbyb4338e12012-08-13 13:44:59 +01002062 INIT_LIST_HEAD(&gsm->tx_list);
Alan Coxe1eaea42010-03-26 11:32:54 +00002063}
2064EXPORT_SYMBOL_GPL(gsm_cleanup_mux);
2065
2066/**
2067 * gsm_activate_mux - generic GSM setup
2068 * @gsm: our mux
2069 *
2070 * Set up the bits of the mux which are the same for all framing
2071 * protocols. Add the mux to the mux table so it can be opened and
2072 * finally kick off connecting to DLCI 0 on the modem.
2073 */
2074
2075int gsm_activate_mux(struct gsm_mux *gsm)
2076{
2077 struct gsm_dlci *dlci;
2078 int i = 0;
2079
2080 init_timer(&gsm->t2_timer);
2081 gsm->t2_timer.function = gsm_control_retransmit;
2082 gsm->t2_timer.data = (unsigned long)gsm;
2083 init_waitqueue_head(&gsm->event);
2084 spin_lock_init(&gsm->control_lock);
2085 spin_lock_init(&gsm->tx_lock);
2086
2087 if (gsm->encoding == 0)
2088 gsm->receive = gsm0_receive;
2089 else
2090 gsm->receive = gsm1_receive;
2091 gsm->error = gsm_error;
2092
2093 spin_lock(&gsm_mux_lock);
2094 for (i = 0; i < MAX_MUX; i++) {
2095 if (gsm_mux[i] == NULL) {
Russ Gorbyd50f6dc2011-06-14 13:35:32 -07002096 gsm->num = i;
Alan Coxe1eaea42010-03-26 11:32:54 +00002097 gsm_mux[i] = gsm;
2098 break;
2099 }
2100 }
2101 spin_unlock(&gsm_mux_lock);
2102 if (i == MAX_MUX)
2103 return -EBUSY;
2104
2105 dlci = gsm_dlci_alloc(gsm, 0);
2106 if (dlci == NULL)
2107 return -ENOMEM;
2108 gsm->dead = 0; /* Tty opens are now permissible */
2109 return 0;
2110}
2111EXPORT_SYMBOL_GPL(gsm_activate_mux);
2112
2113/**
2114 * gsm_free_mux - free up a mux
2115 * @mux: mux to free
2116 *
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002117 * Dispose of allocated resources for a dead mux
Alan Coxe1eaea42010-03-26 11:32:54 +00002118 */
2119void gsm_free_mux(struct gsm_mux *gsm)
2120{
2121 kfree(gsm->txframe);
2122 kfree(gsm->buf);
2123 kfree(gsm);
2124}
2125EXPORT_SYMBOL_GPL(gsm_free_mux);
2126
2127/**
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002128 * gsm_free_muxr - free up a mux
2129 * @mux: mux to free
2130 *
2131 * Dispose of allocated resources for a dead mux
2132 */
2133static void gsm_free_muxr(struct kref *ref)
2134{
2135 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref);
2136 gsm_free_mux(gsm);
2137}
2138
2139static inline void mux_get(struct gsm_mux *gsm)
2140{
2141 kref_get(&gsm->ref);
2142}
2143
2144static inline void mux_put(struct gsm_mux *gsm)
2145{
2146 kref_put(&gsm->ref, gsm_free_muxr);
2147}
2148
2149/**
Alan Coxe1eaea42010-03-26 11:32:54 +00002150 * gsm_alloc_mux - allocate a mux
2151 *
2152 * Creates a new mux ready for activation.
2153 */
2154
2155struct gsm_mux *gsm_alloc_mux(void)
2156{
2157 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
2158 if (gsm == NULL)
2159 return NULL;
2160 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL);
2161 if (gsm->buf == NULL) {
2162 kfree(gsm);
2163 return NULL;
2164 }
2165 gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL);
2166 if (gsm->txframe == NULL) {
2167 kfree(gsm->buf);
2168 kfree(gsm);
2169 return NULL;
2170 }
2171 spin_lock_init(&gsm->lock);
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002172 kref_init(&gsm->ref);
Russ Gorbyb4338e12012-08-13 13:44:59 +01002173 INIT_LIST_HEAD(&gsm->tx_list);
Alan Coxe1eaea42010-03-26 11:32:54 +00002174
2175 gsm->t1 = T1;
2176 gsm->t2 = T2;
2177 gsm->n2 = N2;
2178 gsm->ftype = UIH;
Alan Coxe1eaea42010-03-26 11:32:54 +00002179 gsm->adaption = 1;
2180 gsm->encoding = 1;
2181 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
2182 gsm->mtu = 64;
2183 gsm->dead = 1; /* Avoid early tty opens */
2184
2185 return gsm;
2186}
2187EXPORT_SYMBOL_GPL(gsm_alloc_mux);
2188
Alan Coxe1eaea42010-03-26 11:32:54 +00002189/**
2190 * gsmld_output - write to link
2191 * @gsm: our mux
2192 * @data: bytes to output
2193 * @len: size
2194 *
2195 * Write a block of data from the GSM mux to the data channel. This
2196 * will eventually be serialized from above but at the moment isn't.
2197 */
2198
2199static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
2200{
2201 if (tty_write_room(gsm->tty) < len) {
2202 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
2203 return -ENOSPC;
2204 }
Joe Perches0a77c4f2011-04-25 16:46:49 -07002205 if (debug & 4)
2206 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET,
2207 data, len);
Alan Coxe1eaea42010-03-26 11:32:54 +00002208 gsm->tty->ops->write(gsm->tty, data, len);
2209 return len;
2210}
2211
2212/**
2213 * gsmld_attach_gsm - mode set up
2214 * @tty: our tty structure
2215 * @gsm: our mux
2216 *
2217 * Set up the MUX for basic mode and commence connecting to the
2218 * modem. Currently called from the line discipline set up but
2219 * will need moving to an ioctl path.
2220 */
2221
2222static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2223{
Russ Gorbyd50f6dc2011-06-14 13:35:32 -07002224 int ret, i;
2225 int base = gsm->num << 6; /* Base for this MUX */
Alan Coxe1eaea42010-03-26 11:32:54 +00002226
2227 gsm->tty = tty_kref_get(tty);
2228 gsm->output = gsmld_output;
2229 ret = gsm_activate_mux(gsm);
2230 if (ret != 0)
2231 tty_kref_put(gsm->tty);
Russ Gorbyd50f6dc2011-06-14 13:35:32 -07002232 else {
2233 /* Don't register device 0 - this is the control channel and not
2234 a usable tty interface */
2235 for (i = 1; i < NUM_DLCI; i++)
2236 tty_register_device(gsm_tty_driver, base + i, NULL);
2237 }
Alan Coxe1eaea42010-03-26 11:32:54 +00002238 return ret;
2239}
2240
2241
2242/**
2243 * gsmld_detach_gsm - stop doing 0710 mux
Justin P. Mattock70f23fd2011-05-10 10:16:21 +02002244 * @tty: tty attached to the mux
Alan Coxe1eaea42010-03-26 11:32:54 +00002245 * @gsm: mux
2246 *
2247 * Shutdown and then clean up the resources used by the line discipline
2248 */
2249
2250static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2251{
Russ Gorbyd50f6dc2011-06-14 13:35:32 -07002252 int i;
2253 int base = gsm->num << 6; /* Base for this MUX */
2254
Alan Coxe1eaea42010-03-26 11:32:54 +00002255 WARN_ON(tty != gsm->tty);
Russ Gorbyd50f6dc2011-06-14 13:35:32 -07002256 for (i = 1; i < NUM_DLCI; i++)
2257 tty_unregister_device(gsm_tty_driver, base + i);
Alan Coxe1eaea42010-03-26 11:32:54 +00002258 gsm_cleanup_mux(gsm);
2259 tty_kref_put(gsm->tty);
2260 gsm->tty = NULL;
2261}
2262
Linus Torvalds55db4c62011-06-04 06:33:24 +09002263static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
2264 char *fp, int count)
Alan Coxe1eaea42010-03-26 11:32:54 +00002265{
2266 struct gsm_mux *gsm = tty->disc_data;
2267 const unsigned char *dp;
2268 char *f;
2269 int i;
2270 char buf[64];
2271 char flags;
2272
Joe Perches0a77c4f2011-04-25 16:46:49 -07002273 if (debug & 4)
2274 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET,
2275 cp, count);
Alan Coxe1eaea42010-03-26 11:32:54 +00002276
2277 for (i = count, dp = cp, f = fp; i; i--, dp++) {
2278 flags = *f++;
2279 switch (flags) {
2280 case TTY_NORMAL:
2281 gsm->receive(gsm, *dp);
2282 break;
2283 case TTY_OVERRUN:
2284 case TTY_BREAK:
2285 case TTY_PARITY:
2286 case TTY_FRAME:
2287 gsm->error(gsm, *dp, flags);
2288 break;
2289 default:
Frederic Beratc01af4f2012-08-13 13:43:58 +01002290 WARN_ONCE(1, "%s: unknown flag %d\n",
Alan Coxe1eaea42010-03-26 11:32:54 +00002291 tty_name(tty, buf), flags);
2292 break;
2293 }
2294 }
2295 /* FASYNC if needed ? */
2296 /* If clogged call tty_throttle(tty); */
2297}
2298
2299/**
2300 * gsmld_chars_in_buffer - report available bytes
2301 * @tty: tty device
2302 *
2303 * Report the number of characters buffered to be delivered to user
2304 * at this instant in time.
2305 *
2306 * Locking: gsm lock
2307 */
2308
2309static ssize_t gsmld_chars_in_buffer(struct tty_struct *tty)
2310{
2311 return 0;
2312}
2313
2314/**
2315 * gsmld_flush_buffer - clean input queue
2316 * @tty: terminal device
2317 *
2318 * Flush the input buffer. Called when the line discipline is
2319 * being closed, when the tty layer wants the buffer flushed (eg
2320 * at hangup).
2321 */
2322
2323static void gsmld_flush_buffer(struct tty_struct *tty)
2324{
2325}
2326
2327/**
2328 * gsmld_close - close the ldisc for this tty
2329 * @tty: device
2330 *
2331 * Called from the terminal layer when this line discipline is
2332 * being shut down, either because of a close or becsuse of a
2333 * discipline change. The function will not be called while other
2334 * ldisc methods are in progress.
2335 */
2336
2337static void gsmld_close(struct tty_struct *tty)
2338{
2339 struct gsm_mux *gsm = tty->disc_data;
2340
2341 gsmld_detach_gsm(tty, gsm);
2342
2343 gsmld_flush_buffer(tty);
2344 /* Do other clean up here */
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002345 mux_put(gsm);
Alan Coxe1eaea42010-03-26 11:32:54 +00002346}
2347
2348/**
2349 * gsmld_open - open an ldisc
2350 * @tty: terminal to open
2351 *
2352 * Called when this line discipline is being attached to the
2353 * terminal device. Can sleep. Called serialized so that no
2354 * other events will occur in parallel. No further open will occur
2355 * until a close.
2356 */
2357
2358static int gsmld_open(struct tty_struct *tty)
2359{
2360 struct gsm_mux *gsm;
2361
2362 if (tty->ops->write == NULL)
2363 return -EINVAL;
2364
2365 /* Attach our ldisc data */
2366 gsm = gsm_alloc_mux();
2367 if (gsm == NULL)
2368 return -ENOMEM;
2369
2370 tty->disc_data = gsm;
2371 tty->receive_room = 65536;
2372
2373 /* Attach the initial passive connection */
2374 gsm->encoding = 1;
2375 return gsmld_attach_gsm(tty, gsm);
2376}
2377
2378/**
2379 * gsmld_write_wakeup - asynchronous I/O notifier
2380 * @tty: tty device
2381 *
2382 * Required for the ptys, serial driver etc. since processes
2383 * that attach themselves to the master and rely on ASYNC
2384 * IO must be woken up
2385 */
2386
2387static void gsmld_write_wakeup(struct tty_struct *tty)
2388{
2389 struct gsm_mux *gsm = tty->disc_data;
Dan Carpenter328be392010-05-25 11:37:17 +02002390 unsigned long flags;
Alan Coxe1eaea42010-03-26 11:32:54 +00002391
2392 /* Queue poll */
2393 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
Russ Gorby5e447082012-08-13 13:44:40 +01002394 spin_lock_irqsave(&gsm->tx_lock, flags);
Alan Coxe1eaea42010-03-26 11:32:54 +00002395 gsm_data_kick(gsm);
Dan Carpenter328be392010-05-25 11:37:17 +02002396 if (gsm->tx_bytes < TX_THRESH_LO) {
Alan Coxe1eaea42010-03-26 11:32:54 +00002397 gsm_dlci_data_sweep(gsm);
Dan Carpenter328be392010-05-25 11:37:17 +02002398 }
Russ Gorby5e447082012-08-13 13:44:40 +01002399 spin_unlock_irqrestore(&gsm->tx_lock, flags);
Alan Coxe1eaea42010-03-26 11:32:54 +00002400}
2401
2402/**
2403 * gsmld_read - read function for tty
2404 * @tty: tty device
2405 * @file: file object
2406 * @buf: userspace buffer pointer
2407 * @nr: size of I/O
2408 *
2409 * Perform reads for the line discipline. We are guaranteed that the
2410 * line discipline will not be closed under us but we may get multiple
2411 * parallel readers and must handle this ourselves. We may also get
2412 * a hangup. Always called in user context, may sleep.
2413 *
2414 * This code must be sure never to sleep through a hangup.
2415 */
2416
2417static ssize_t gsmld_read(struct tty_struct *tty, struct file *file,
2418 unsigned char __user *buf, size_t nr)
2419{
2420 return -EOPNOTSUPP;
2421}
2422
2423/**
2424 * gsmld_write - write function for tty
2425 * @tty: tty device
2426 * @file: file object
2427 * @buf: userspace buffer pointer
2428 * @nr: size of I/O
2429 *
2430 * Called when the owner of the device wants to send a frame
2431 * itself (or some other control data). The data is transferred
2432 * as-is and must be properly framed and checksummed as appropriate
2433 * by userspace. Frames are either sent whole or not at all as this
2434 * avoids pain user side.
2435 */
2436
2437static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
2438 const unsigned char *buf, size_t nr)
2439{
2440 int space = tty_write_room(tty);
2441 if (space >= nr)
2442 return tty->ops->write(tty, buf, nr);
2443 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2444 return -ENOBUFS;
2445}
2446
2447/**
2448 * gsmld_poll - poll method for N_GSM0710
2449 * @tty: terminal device
2450 * @file: file accessing it
2451 * @wait: poll table
2452 *
2453 * Called when the line discipline is asked to poll() for data or
2454 * for special events. This code is not serialized with respect to
2455 * other events save open/close.
2456 *
2457 * This code must be sure never to sleep through a hangup.
2458 * Called without the kernel lock held - fine
2459 */
2460
2461static unsigned int gsmld_poll(struct tty_struct *tty, struct file *file,
2462 poll_table *wait)
2463{
2464 unsigned int mask = 0;
2465 struct gsm_mux *gsm = tty->disc_data;
2466
2467 poll_wait(file, &tty->read_wait, wait);
2468 poll_wait(file, &tty->write_wait, wait);
2469 if (tty_hung_up_p(file))
2470 mask |= POLLHUP;
2471 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
2472 mask |= POLLOUT | POLLWRNORM;
2473 if (gsm->dead)
2474 mask |= POLLHUP;
2475 return mask;
2476}
2477
2478static int gsmld_config(struct tty_struct *tty, struct gsm_mux *gsm,
2479 struct gsm_config *c)
2480{
2481 int need_close = 0;
2482 int need_restart = 0;
2483
2484 /* Stuff we don't support yet - UI or I frame transport, windowing */
Alan Cox5f9a31d2010-11-04 15:17:27 +00002485 if ((c->adaption != 1 && c->adaption != 2) || c->k)
Alan Coxe1eaea42010-03-26 11:32:54 +00002486 return -EOPNOTSUPP;
2487 /* Check the MRU/MTU range looks sane */
2488 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8)
2489 return -EINVAL;
2490 if (c->n2 < 3)
2491 return -EINVAL;
2492 if (c->encapsulation > 1) /* Basic, advanced, no I */
2493 return -EINVAL;
2494 if (c->initiator > 1)
2495 return -EINVAL;
2496 if (c->i == 0 || c->i > 2) /* UIH and UI only */
2497 return -EINVAL;
2498 /*
2499 * See what is needed for reconfiguration
2500 */
2501
2502 /* Timing fields */
2503 if (c->t1 != 0 && c->t1 != gsm->t1)
2504 need_restart = 1;
2505 if (c->t2 != 0 && c->t2 != gsm->t2)
2506 need_restart = 1;
2507 if (c->encapsulation != gsm->encoding)
2508 need_restart = 1;
2509 if (c->adaption != gsm->adaption)
2510 need_restart = 1;
2511 /* Requires care */
2512 if (c->initiator != gsm->initiator)
2513 need_close = 1;
2514 if (c->mru != gsm->mru)
2515 need_restart = 1;
2516 if (c->mtu != gsm->mtu)
2517 need_restart = 1;
2518
2519 /*
2520 * Close down what is needed, restart and initiate the new
2521 * configuration
2522 */
2523
2524 if (need_close || need_restart) {
2525 gsm_dlci_begin_close(gsm->dlci[0]);
2526 /* This will timeout if the link is down due to N2 expiring */
2527 wait_event_interruptible(gsm->event,
2528 gsm->dlci[0]->state == DLCI_CLOSED);
2529 if (signal_pending(current))
2530 return -EINTR;
2531 }
2532 if (need_restart)
2533 gsm_cleanup_mux(gsm);
2534
2535 gsm->initiator = c->initiator;
2536 gsm->mru = c->mru;
Ken Mills91f78f32011-01-25 14:17:45 +00002537 gsm->mtu = c->mtu;
Alan Coxe1eaea42010-03-26 11:32:54 +00002538 gsm->encoding = c->encapsulation;
2539 gsm->adaption = c->adaption;
Ken Mills820e62e2010-11-04 15:16:24 +00002540 gsm->n2 = c->n2;
Alan Coxe1eaea42010-03-26 11:32:54 +00002541
2542 if (c->i == 1)
2543 gsm->ftype = UIH;
2544 else if (c->i == 2)
2545 gsm->ftype = UI;
2546
2547 if (c->t1)
2548 gsm->t1 = c->t1;
2549 if (c->t2)
2550 gsm->t2 = c->t2;
2551
2552 /* FIXME: We need to separate activation/deactivation from adding
2553 and removing from the mux array */
2554 if (need_restart)
2555 gsm_activate_mux(gsm);
2556 if (gsm->initiator && need_close)
2557 gsm_dlci_begin_open(gsm->dlci[0]);
2558 return 0;
2559}
2560
2561static int gsmld_ioctl(struct tty_struct *tty, struct file *file,
2562 unsigned int cmd, unsigned long arg)
2563{
2564 struct gsm_config c;
2565 struct gsm_mux *gsm = tty->disc_data;
2566
2567 switch (cmd) {
2568 case GSMIOC_GETCONF:
2569 memset(&c, 0, sizeof(c));
2570 c.adaption = gsm->adaption;
2571 c.encapsulation = gsm->encoding;
2572 c.initiator = gsm->initiator;
2573 c.t1 = gsm->t1;
2574 c.t2 = gsm->t2;
2575 c.t3 = 0; /* Not supported */
2576 c.n2 = gsm->n2;
2577 if (gsm->ftype == UIH)
2578 c.i = 1;
2579 else
2580 c.i = 2;
Alan Cox5f9a31d2010-11-04 15:17:27 +00002581 pr_debug("Ftype %d i %d\n", gsm->ftype, c.i);
Alan Coxe1eaea42010-03-26 11:32:54 +00002582 c.mru = gsm->mru;
2583 c.mtu = gsm->mtu;
2584 c.k = 0;
2585 if (copy_to_user((void *)arg, &c, sizeof(c)))
2586 return -EFAULT;
2587 return 0;
2588 case GSMIOC_SETCONF:
2589 if (copy_from_user(&c, (void *)arg, sizeof(c)))
2590 return -EFAULT;
2591 return gsmld_config(tty, gsm, &c);
2592 default:
2593 return n_tty_ioctl_helper(tty, file, cmd, arg);
2594 }
2595}
2596
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002597/*
2598 * Network interface
2599 *
2600 */
2601
2602static int gsm_mux_net_open(struct net_device *net)
2603{
2604 pr_debug("%s called\n", __func__);
2605 netif_start_queue(net);
2606 return 0;
2607}
2608
2609static int gsm_mux_net_close(struct net_device *net)
2610{
2611 netif_stop_queue(net);
2612 return 0;
2613}
2614
2615static struct net_device_stats *gsm_mux_net_get_stats(struct net_device *net)
2616{
2617 return &((struct gsm_mux_net *)netdev_priv(net))->stats;
2618}
2619static void dlci_net_free(struct gsm_dlci *dlci)
2620{
2621 if (!dlci->net) {
2622 WARN_ON(1);
2623 return;
2624 }
2625 dlci->adaption = dlci->prev_adaption;
2626 dlci->data = dlci->prev_data;
2627 free_netdev(dlci->net);
2628 dlci->net = NULL;
2629}
2630static void net_free(struct kref *ref)
2631{
2632 struct gsm_mux_net *mux_net;
2633 struct gsm_dlci *dlci;
2634
2635 mux_net = container_of(ref, struct gsm_mux_net, ref);
2636 dlci = mux_net->dlci;
2637
2638 if (dlci->net) {
2639 unregister_netdev(dlci->net);
2640 dlci_net_free(dlci);
2641 }
2642}
2643
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002644static inline void muxnet_get(struct gsm_mux_net *mux_net)
2645{
2646 kref_get(&mux_net->ref);
2647}
2648
2649static inline void muxnet_put(struct gsm_mux_net *mux_net)
2650{
2651 kref_put(&mux_net->ref, net_free);
2652}
2653
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002654static int gsm_mux_net_start_xmit(struct sk_buff *skb,
2655 struct net_device *net)
2656{
2657 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
2658 struct gsm_dlci *dlci = mux_net->dlci;
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002659 muxnet_get(mux_net);
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002660
2661 skb_queue_head(&dlci->skb_list, skb);
2662 STATS(net).tx_packets++;
2663 STATS(net).tx_bytes += skb->len;
2664 gsm_dlci_data_kick(dlci);
2665 /* And tell the kernel when the last transmit started. */
2666 net->trans_start = jiffies;
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002667 muxnet_put(mux_net);
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002668 return NETDEV_TX_OK;
2669}
2670
2671/* called when a packet did not ack after watchdogtimeout */
2672static void gsm_mux_net_tx_timeout(struct net_device *net)
2673{
2674 /* Tell syslog we are hosed. */
2675 dev_dbg(&net->dev, "Tx timed out.\n");
2676
2677 /* Update statistics */
2678 STATS(net).tx_errors++;
2679}
2680
2681static void gsm_mux_rx_netchar(struct gsm_dlci *dlci,
2682 unsigned char *in_buf, int size)
2683{
2684 struct net_device *net = dlci->net;
2685 struct sk_buff *skb;
2686 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002687 muxnet_get(mux_net);
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002688
2689 /* Allocate an sk_buff */
2690 skb = dev_alloc_skb(size + NET_IP_ALIGN);
2691 if (!skb) {
2692 /* We got no receive buffer. */
2693 STATS(net).rx_dropped++;
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002694 muxnet_put(mux_net);
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002695 return;
2696 }
2697 skb_reserve(skb, NET_IP_ALIGN);
2698 memcpy(skb_put(skb, size), in_buf, size);
2699
2700 skb->dev = net;
2701 skb->protocol = __constant_htons(ETH_P_IP);
2702
2703 /* Ship it off to the kernel */
2704 netif_rx(skb);
2705
2706 /* update out statistics */
2707 STATS(net).rx_packets++;
2708 STATS(net).rx_bytes += size;
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002709 muxnet_put(mux_net);
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002710 return;
2711}
2712
2713int gsm_change_mtu(struct net_device *net, int new_mtu)
2714{
2715 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
2716 if ((new_mtu < 8) || (new_mtu > mux_net->dlci->gsm->mtu))
2717 return -EINVAL;
2718 net->mtu = new_mtu;
2719 return 0;
2720}
2721
2722static void gsm_mux_net_init(struct net_device *net)
2723{
2724 static const struct net_device_ops gsm_netdev_ops = {
2725 .ndo_open = gsm_mux_net_open,
2726 .ndo_stop = gsm_mux_net_close,
2727 .ndo_start_xmit = gsm_mux_net_start_xmit,
2728 .ndo_tx_timeout = gsm_mux_net_tx_timeout,
2729 .ndo_get_stats = gsm_mux_net_get_stats,
2730 .ndo_change_mtu = gsm_change_mtu,
2731 };
2732
2733 net->netdev_ops = &gsm_netdev_ops;
2734
2735 /* fill in the other fields */
2736 net->watchdog_timeo = GSM_NET_TX_TIMEOUT;
2737 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
2738 net->type = ARPHRD_NONE;
2739 net->tx_queue_len = 10;
2740}
2741
2742
2743/* caller holds the dlci mutex */
2744static void gsm_destroy_network(struct gsm_dlci *dlci)
2745{
2746 struct gsm_mux_net *mux_net;
2747
2748 pr_debug("destroy network interface");
2749 if (!dlci->net)
2750 return;
2751 mux_net = (struct gsm_mux_net *)netdev_priv(dlci->net);
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002752 muxnet_put(mux_net);
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002753}
2754
2755
2756/* caller holds the dlci mutex */
2757static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
2758{
2759 char *netname;
2760 int retval = 0;
2761 struct net_device *net;
2762 struct gsm_mux_net *mux_net;
2763
2764 if (!capable(CAP_NET_ADMIN))
2765 return -EPERM;
2766
2767 /* Already in a non tty mode */
2768 if (dlci->adaption > 2)
2769 return -EBUSY;
2770
2771 if (nc->protocol != htons(ETH_P_IP))
2772 return -EPROTONOSUPPORT;
2773
2774 if (nc->adaption != 3 && nc->adaption != 4)
2775 return -EPROTONOSUPPORT;
2776
2777 pr_debug("create network interface");
2778
2779 netname = "gsm%d";
2780 if (nc->if_name[0] != '\0')
2781 netname = nc->if_name;
2782 net = alloc_netdev(sizeof(struct gsm_mux_net),
2783 netname,
2784 gsm_mux_net_init);
2785 if (!net) {
2786 pr_err("alloc_netdev failed");
2787 return -ENOMEM;
2788 }
2789 net->mtu = dlci->gsm->mtu;
2790 mux_net = (struct gsm_mux_net *)netdev_priv(net);
2791 mux_net->dlci = dlci;
2792 kref_init(&mux_net->ref);
2793 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */
2794
2795 /* reconfigure dlci for network */
2796 dlci->prev_adaption = dlci->adaption;
2797 dlci->prev_data = dlci->data;
2798 dlci->adaption = nc->adaption;
2799 dlci->data = gsm_mux_rx_netchar;
2800 dlci->net = net;
2801
2802 pr_debug("register netdev");
2803 retval = register_netdev(net);
2804 if (retval) {
2805 pr_err("network register fail %d\n", retval);
2806 dlci_net_free(dlci);
2807 return retval;
2808 }
2809 return net->ifindex; /* return network index */
2810}
Alan Coxe1eaea42010-03-26 11:32:54 +00002811
2812/* Line discipline for real tty */
2813struct tty_ldisc_ops tty_ldisc_packet = {
2814 .owner = THIS_MODULE,
2815 .magic = TTY_LDISC_MAGIC,
2816 .name = "n_gsm",
2817 .open = gsmld_open,
2818 .close = gsmld_close,
2819 .flush_buffer = gsmld_flush_buffer,
2820 .chars_in_buffer = gsmld_chars_in_buffer,
2821 .read = gsmld_read,
2822 .write = gsmld_write,
2823 .ioctl = gsmld_ioctl,
2824 .poll = gsmld_poll,
2825 .receive_buf = gsmld_receive_buf,
2826 .write_wakeup = gsmld_write_wakeup
2827};
2828
2829/*
2830 * Virtual tty side
2831 */
2832
2833#define TX_SIZE 512
2834
2835static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk)
2836{
2837 u8 modembits[5];
2838 struct gsm_control *ctrl;
2839 int len = 2;
2840
2841 if (brk)
2842 len++;
2843
2844 modembits[0] = len << 1 | EA; /* Data bytes */
2845 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */
2846 modembits[2] = gsm_encode_modem(dlci) << 1 | EA;
2847 if (brk)
2848 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */
2849 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1);
2850 if (ctrl == NULL)
2851 return -ENOMEM;
2852 return gsm_control_wait(dlci->gsm, ctrl);
2853}
2854
2855static int gsm_carrier_raised(struct tty_port *port)
2856{
2857 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2858 /* Not yet open so no carrier info */
2859 if (dlci->state != DLCI_OPEN)
2860 return 0;
2861 if (debug & 2)
2862 return 1;
2863 return dlci->modem_rx & TIOCM_CD;
2864}
2865
2866static void gsm_dtr_rts(struct tty_port *port, int onoff)
2867{
2868 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2869 unsigned int modem_tx = dlci->modem_tx;
2870 if (onoff)
2871 modem_tx |= TIOCM_DTR | TIOCM_RTS;
2872 else
2873 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
2874 if (modem_tx != dlci->modem_tx) {
2875 dlci->modem_tx = modem_tx;
2876 gsmtty_modem_update(dlci, 0);
2877 }
2878}
2879
2880static const struct tty_port_operations gsm_port_ops = {
2881 .carrier_raised = gsm_carrier_raised,
2882 .dtr_rts = gsm_dtr_rts,
Jiri Slaby9a8e62b2012-11-15 09:49:53 +01002883 .destruct = gsm_dlci_free,
Alan Coxe1eaea42010-03-26 11:32:54 +00002884};
2885
Jiri Slaby86176ed2012-08-07 21:47:28 +02002886static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty)
Alan Coxe1eaea42010-03-26 11:32:54 +00002887{
2888 struct gsm_mux *gsm;
2889 struct gsm_dlci *dlci;
Alan Coxe1eaea42010-03-26 11:32:54 +00002890 unsigned int line = tty->index;
2891 unsigned int mux = line >> 6;
Jiri Slaby86176ed2012-08-07 21:47:28 +02002892 bool alloc = false;
2893 int ret;
Alan Coxe1eaea42010-03-26 11:32:54 +00002894
2895 line = line & 0x3F;
2896
2897 if (mux >= MAX_MUX)
2898 return -ENXIO;
2899 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
2900 if (gsm_mux[mux] == NULL)
2901 return -EUNATCH;
2902 if (line == 0 || line > 61) /* 62/63 reserved */
2903 return -ECHRNG;
2904 gsm = gsm_mux[mux];
2905 if (gsm->dead)
2906 return -EL2HLT;
xiaojin7e8ac7b2012-08-13 13:43:15 +01002907 /* If DLCI 0 is not yet fully open return an error. This is ok from a locking
2908 perspective as we don't have to worry about this if DLCI0 is lost */
2909 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN)
2910 return -EL2NSYNC;
Alan Coxe1eaea42010-03-26 11:32:54 +00002911 dlci = gsm->dlci[line];
Jiri Slaby86176ed2012-08-07 21:47:28 +02002912 if (dlci == NULL) {
2913 alloc = true;
Alan Coxe1eaea42010-03-26 11:32:54 +00002914 dlci = gsm_dlci_alloc(gsm, line);
Jiri Slaby86176ed2012-08-07 21:47:28 +02002915 }
Alan Coxe1eaea42010-03-26 11:32:54 +00002916 if (dlci == NULL)
2917 return -ENOMEM;
Jiri Slaby86176ed2012-08-07 21:47:28 +02002918 ret = tty_port_install(&dlci->port, driver, tty);
2919 if (ret) {
2920 if (alloc)
2921 dlci_put(dlci);
2922 return ret;
2923 }
2924
Alan Coxe1eaea42010-03-26 11:32:54 +00002925 tty->driver_data = dlci;
Jiri Slaby86176ed2012-08-07 21:47:28 +02002926
2927 return 0;
2928}
2929
2930static int gsmtty_open(struct tty_struct *tty, struct file *filp)
2931{
2932 struct gsm_dlci *dlci = tty->driver_data;
2933 struct tty_port *port = &dlci->port;
2934
2935 port->count++;
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002936 dlci_get(dlci);
2937 dlci_get(dlci->gsm->dlci[0]);
2938 mux_get(dlci->gsm);
Alan Coxe1eaea42010-03-26 11:32:54 +00002939 tty_port_tty_set(port, tty);
2940
2941 dlci->modem_rx = 0;
2942 /* We could in theory open and close before we wait - eg if we get
2943 a DM straight back. This is ok as that will have caused a hangup */
2944 set_bit(ASYNCB_INITIALIZED, &port->flags);
2945 /* Start sending off SABM messages */
2946 gsm_dlci_begin_open(dlci);
2947 /* And wait for virtual carrier */
2948 return tty_port_block_til_ready(port, tty, filp);
2949}
2950
2951static void gsmtty_close(struct tty_struct *tty, struct file *filp)
2952{
2953 struct gsm_dlci *dlci = tty->driver_data;
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002954 struct gsm_mux *gsm;
2955
Alan Coxe1eaea42010-03-26 11:32:54 +00002956 if (dlci == NULL)
2957 return;
Dirkjan Bussink4d9b1092013-01-30 11:44:50 +01002958 if (dlci->state == DLCI_CLOSED)
2959 return;
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002960 mutex_lock(&dlci->mutex);
2961 gsm_destroy_network(dlci);
2962 mutex_unlock(&dlci->mutex);
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002963 gsm = dlci->gsm;
Alan Coxe1eaea42010-03-26 11:32:54 +00002964 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002965 goto out;
Alan Coxe1eaea42010-03-26 11:32:54 +00002966 gsm_dlci_begin_close(dlci);
Johan Hovold957daca2013-03-07 15:55:51 +01002967 if (test_bit(ASYNCB_INITIALIZED, &dlci->port.flags)) {
2968 if (C_HUPCL(tty))
2969 tty_port_lower_dtr_rts(&dlci->port);
2970 }
Alan Coxe1eaea42010-03-26 11:32:54 +00002971 tty_port_close_end(&dlci->port, tty);
2972 tty_port_tty_set(&dlci->port, NULL);
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002973out:
2974 dlci_put(dlci);
2975 dlci_put(gsm->dlci[0]);
2976 mux_put(gsm);
Alan Coxe1eaea42010-03-26 11:32:54 +00002977}
2978
2979static void gsmtty_hangup(struct tty_struct *tty)
2980{
2981 struct gsm_dlci *dlci = tty->driver_data;
Dirkjan Bussink4d9b1092013-01-30 11:44:50 +01002982 if (dlci->state == DLCI_CLOSED)
2983 return;
Alan Coxe1eaea42010-03-26 11:32:54 +00002984 tty_port_hangup(&dlci->port);
2985 gsm_dlci_begin_close(dlci);
2986}
2987
2988static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf,
2989 int len)
2990{
Dirkjan Bussink4d9b1092013-01-30 11:44:50 +01002991 int sent;
Alan Coxe1eaea42010-03-26 11:32:54 +00002992 struct gsm_dlci *dlci = tty->driver_data;
Dirkjan Bussink4d9b1092013-01-30 11:44:50 +01002993 if (dlci->state == DLCI_CLOSED)
2994 return -EINVAL;
Alan Coxe1eaea42010-03-26 11:32:54 +00002995 /* Stuff the bytes into the fifo queue */
Dirkjan Bussink4d9b1092013-01-30 11:44:50 +01002996 sent = kfifo_in_locked(dlci->fifo, buf, len, &dlci->lock);
Alan Coxe1eaea42010-03-26 11:32:54 +00002997 /* Need to kick the channel */
2998 gsm_dlci_data_kick(dlci);
2999 return sent;
3000}
3001
3002static int gsmtty_write_room(struct tty_struct *tty)
3003{
3004 struct gsm_dlci *dlci = tty->driver_data;
Dirkjan Bussink4d9b1092013-01-30 11:44:50 +01003005 if (dlci->state == DLCI_CLOSED)
3006 return -EINVAL;
Alan Coxe1eaea42010-03-26 11:32:54 +00003007 return TX_SIZE - kfifo_len(dlci->fifo);
3008}
3009
3010static int gsmtty_chars_in_buffer(struct tty_struct *tty)
3011{
3012 struct gsm_dlci *dlci = tty->driver_data;
Dirkjan Bussink4d9b1092013-01-30 11:44:50 +01003013 if (dlci->state == DLCI_CLOSED)
3014 return -EINVAL;
Alan Coxe1eaea42010-03-26 11:32:54 +00003015 return kfifo_len(dlci->fifo);
3016}
3017
3018static void gsmtty_flush_buffer(struct tty_struct *tty)
3019{
3020 struct gsm_dlci *dlci = tty->driver_data;
Dirkjan Bussink4d9b1092013-01-30 11:44:50 +01003021 if (dlci->state == DLCI_CLOSED)
3022 return;
Alan Coxe1eaea42010-03-26 11:32:54 +00003023 /* Caution needed: If we implement reliable transport classes
3024 then the data being transmitted can't simply be junked once
3025 it has first hit the stack. Until then we can just blow it
3026 away */
3027 kfifo_reset(dlci->fifo);
3028 /* Need to unhook this DLCI from the transmit queue logic */
3029}
3030
3031static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
3032{
3033 /* The FIFO handles the queue so the kernel will do the right
3034 thing waiting on chars_in_buffer before calling us. No work
3035 to do here */
3036}
3037
Alan Cox60b33c12011-02-14 16:26:14 +00003038static int gsmtty_tiocmget(struct tty_struct *tty)
Alan Coxe1eaea42010-03-26 11:32:54 +00003039{
3040 struct gsm_dlci *dlci = tty->driver_data;
Dirkjan Bussink4d9b1092013-01-30 11:44:50 +01003041 if (dlci->state == DLCI_CLOSED)
3042 return -EINVAL;
Alan Coxe1eaea42010-03-26 11:32:54 +00003043 return dlci->modem_rx;
3044}
3045
Alan Cox20b9d172011-02-14 16:26:50 +00003046static int gsmtty_tiocmset(struct tty_struct *tty,
Alan Coxe1eaea42010-03-26 11:32:54 +00003047 unsigned int set, unsigned int clear)
3048{
3049 struct gsm_dlci *dlci = tty->driver_data;
3050 unsigned int modem_tx = dlci->modem_tx;
3051
Dirkjan Bussink4d9b1092013-01-30 11:44:50 +01003052 if (dlci->state == DLCI_CLOSED)
3053 return -EINVAL;
Nikola Diklic-Perincf168072011-09-23 10:59:43 +02003054 modem_tx &= ~clear;
Alan Coxe1eaea42010-03-26 11:32:54 +00003055 modem_tx |= set;
3056
3057 if (modem_tx != dlci->modem_tx) {
3058 dlci->modem_tx = modem_tx;
3059 return gsmtty_modem_update(dlci, 0);
3060 }
3061 return 0;
3062}
3063
3064
Alan Cox6caa76b2011-02-14 16:27:22 +00003065static int gsmtty_ioctl(struct tty_struct *tty,
Alan Coxe1eaea42010-03-26 11:32:54 +00003066 unsigned int cmd, unsigned long arg)
3067{
Russ Gorbybcd5abe2011-06-16 14:20:12 -07003068 struct gsm_dlci *dlci = tty->driver_data;
3069 struct gsm_netconfig nc;
3070 int index;
3071
Dirkjan Bussink4d9b1092013-01-30 11:44:50 +01003072 if (dlci->state == DLCI_CLOSED)
3073 return -EINVAL;
Russ Gorbybcd5abe2011-06-16 14:20:12 -07003074 switch (cmd) {
3075 case GSMIOC_ENABLE_NET:
3076 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc)))
3077 return -EFAULT;
3078 nc.if_name[IFNAMSIZ-1] = '\0';
3079 /* return net interface index or error code */
3080 mutex_lock(&dlci->mutex);
3081 index = gsm_create_network(dlci, &nc);
3082 mutex_unlock(&dlci->mutex);
3083 if (copy_to_user((void __user *)arg, &nc, sizeof(nc)))
3084 return -EFAULT;
3085 return index;
3086 case GSMIOC_DISABLE_NET:
3087 if (!capable(CAP_NET_ADMIN))
3088 return -EPERM;
3089 mutex_lock(&dlci->mutex);
3090 gsm_destroy_network(dlci);
3091 mutex_unlock(&dlci->mutex);
3092 return 0;
3093 default:
3094 return -ENOIOCTLCMD;
3095 }
Alan Coxe1eaea42010-03-26 11:32:54 +00003096}
3097
3098static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old)
3099{
Dirkjan Bussink4d9b1092013-01-30 11:44:50 +01003100 struct gsm_dlci *dlci = tty->driver_data;
3101 if (dlci->state == DLCI_CLOSED)
3102 return;
Alan Coxe1eaea42010-03-26 11:32:54 +00003103 /* For the moment its fixed. In actual fact the speed information
3104 for the virtual channel can be propogated in both directions by
3105 the RPN control message. This however rapidly gets nasty as we
3106 then have to remap modem signals each way according to whether
3107 our virtual cable is null modem etc .. */
Alan Coxadc8d742012-07-14 15:31:47 +01003108 tty_termios_copy_hw(&tty->termios, old);
Alan Coxe1eaea42010-03-26 11:32:54 +00003109}
3110
3111static void gsmtty_throttle(struct tty_struct *tty)
3112{
3113 struct gsm_dlci *dlci = tty->driver_data;
Dirkjan Bussink4d9b1092013-01-30 11:44:50 +01003114 if (dlci->state == DLCI_CLOSED)
3115 return;
Alan Coxadc8d742012-07-14 15:31:47 +01003116 if (tty->termios.c_cflag & CRTSCTS)
Alan Coxe1eaea42010-03-26 11:32:54 +00003117 dlci->modem_tx &= ~TIOCM_DTR;
3118 dlci->throttled = 1;
3119 /* Send an MSC with DTR cleared */
3120 gsmtty_modem_update(dlci, 0);
3121}
3122
3123static void gsmtty_unthrottle(struct tty_struct *tty)
3124{
3125 struct gsm_dlci *dlci = tty->driver_data;
Dirkjan Bussink4d9b1092013-01-30 11:44:50 +01003126 if (dlci->state == DLCI_CLOSED)
3127 return;
Alan Coxadc8d742012-07-14 15:31:47 +01003128 if (tty->termios.c_cflag & CRTSCTS)
Alan Coxe1eaea42010-03-26 11:32:54 +00003129 dlci->modem_tx |= TIOCM_DTR;
3130 dlci->throttled = 0;
3131 /* Send an MSC with DTR set */
3132 gsmtty_modem_update(dlci, 0);
3133}
3134
3135static int gsmtty_break_ctl(struct tty_struct *tty, int state)
3136{
3137 struct gsm_dlci *dlci = tty->driver_data;
3138 int encode = 0; /* Off */
Dirkjan Bussink4d9b1092013-01-30 11:44:50 +01003139 if (dlci->state == DLCI_CLOSED)
3140 return -EINVAL;
Alan Coxe1eaea42010-03-26 11:32:54 +00003141
3142 if (state == -1) /* "On indefinitely" - we can't encode this
3143 properly */
3144 encode = 0x0F;
3145 else if (state > 0) {
3146 encode = state / 200; /* mS to encoding */
3147 if (encode > 0x0F)
3148 encode = 0x0F; /* Best effort */
3149 }
3150 return gsmtty_modem_update(dlci, encode);
3151}
3152
Alan Coxe1eaea42010-03-26 11:32:54 +00003153
3154/* Virtual ttys for the demux */
3155static const struct tty_operations gsmtty_ops = {
Jiri Slaby86176ed2012-08-07 21:47:28 +02003156 .install = gsmtty_install,
Alan Coxe1eaea42010-03-26 11:32:54 +00003157 .open = gsmtty_open,
3158 .close = gsmtty_close,
3159 .write = gsmtty_write,
3160 .write_room = gsmtty_write_room,
3161 .chars_in_buffer = gsmtty_chars_in_buffer,
3162 .flush_buffer = gsmtty_flush_buffer,
3163 .ioctl = gsmtty_ioctl,
3164 .throttle = gsmtty_throttle,
3165 .unthrottle = gsmtty_unthrottle,
3166 .set_termios = gsmtty_set_termios,
3167 .hangup = gsmtty_hangup,
3168 .wait_until_sent = gsmtty_wait_until_sent,
3169 .tiocmget = gsmtty_tiocmget,
3170 .tiocmset = gsmtty_tiocmset,
3171 .break_ctl = gsmtty_break_ctl,
3172};
3173
3174
3175
3176static int __init gsm_init(void)
3177{
3178 /* Fill in our line protocol discipline, and register it */
3179 int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet);
3180 if (status != 0) {
Alan Cox5f9a31d2010-11-04 15:17:27 +00003181 pr_err("n_gsm: can't register line discipline (err = %d)\n",
3182 status);
Alan Coxe1eaea42010-03-26 11:32:54 +00003183 return status;
3184 }
3185
3186 gsm_tty_driver = alloc_tty_driver(256);
3187 if (!gsm_tty_driver) {
3188 tty_unregister_ldisc(N_GSM0710);
Alan Cox5f9a31d2010-11-04 15:17:27 +00003189 pr_err("gsm_init: tty allocation failed.\n");
Alan Coxe1eaea42010-03-26 11:32:54 +00003190 return -EINVAL;
3191 }
Alan Coxe1eaea42010-03-26 11:32:54 +00003192 gsm_tty_driver->driver_name = "gsmtty";
3193 gsm_tty_driver->name = "gsmtty";
3194 gsm_tty_driver->major = 0; /* Dynamic */
3195 gsm_tty_driver->minor_start = 0;
3196 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
3197 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
3198 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV
Alan Cox5f9a31d2010-11-04 15:17:27 +00003199 | TTY_DRIVER_HARDWARE_BREAK;
Alan Coxe1eaea42010-03-26 11:32:54 +00003200 gsm_tty_driver->init_termios = tty_std_termios;
3201 /* Fixme */
3202 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
3203 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
3204
3205 spin_lock_init(&gsm_mux_lock);
3206
3207 if (tty_register_driver(gsm_tty_driver)) {
3208 put_tty_driver(gsm_tty_driver);
3209 tty_unregister_ldisc(N_GSM0710);
Alan Cox5f9a31d2010-11-04 15:17:27 +00003210 pr_err("gsm_init: tty registration failed.\n");
Alan Coxe1eaea42010-03-26 11:32:54 +00003211 return -EBUSY;
3212 }
Alan Cox5f9a31d2010-11-04 15:17:27 +00003213 pr_debug("gsm_init: loaded as %d,%d.\n",
3214 gsm_tty_driver->major, gsm_tty_driver->minor_start);
Alan Coxe1eaea42010-03-26 11:32:54 +00003215 return 0;
3216}
3217
3218static void __exit gsm_exit(void)
3219{
3220 int status = tty_unregister_ldisc(N_GSM0710);
3221 if (status != 0)
Alan Cox5f9a31d2010-11-04 15:17:27 +00003222 pr_err("n_gsm: can't unregister line discipline (err = %d)\n",
3223 status);
Alan Coxe1eaea42010-03-26 11:32:54 +00003224 tty_unregister_driver(gsm_tty_driver);
3225 put_tty_driver(gsm_tty_driver);
Alan Coxe1eaea42010-03-26 11:32:54 +00003226}
3227
3228module_init(gsm_init);
3229module_exit(gsm_exit);
3230
3231
3232MODULE_LICENSE("GPL");
3233MODULE_ALIAS_LDISC(N_GSM0710);