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Alan Coxe1eaea42010-03-26 11:32:54 +00001/*
2 * n_gsm.c GSM 0710 tty multiplexor
3 * Copyright (c) 2009/10 Intel Corporation
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
17 *
18 * * THIS IS A DEVELOPMENT SNAPSHOT IT IS NOT A FINAL RELEASE *
19 *
20 * TO DO:
21 * Mostly done: ioctls for setting modes/timing
Alan Cox5f9a31d2010-11-04 15:17:27 +000022 * Partly done: hooks so you can pull off frames to non tty devs
Alan Coxe1eaea42010-03-26 11:32:54 +000023 * Restart DLCI 0 when it closes ?
Alan Coxe1eaea42010-03-26 11:32:54 +000024 * Improve the tx engine
25 * Resolve tx side locking by adding a queue_head and routing
26 * all control traffic via it
27 * General tidy/document
28 * Review the locking/move to refcounts more (mux now moved to an
29 * alloc/free model ready)
30 * Use newest tty open/close port helpers and install hooks
31 * What to do about power functions ?
32 * Termios setting and negotiation
33 * Do we need a 'which mux are you' ioctl to correlate mux and tty sets
34 *
35 */
36
37#include <linux/types.h>
38#include <linux/major.h>
39#include <linux/errno.h>
40#include <linux/signal.h>
41#include <linux/fcntl.h>
42#include <linux/sched.h>
43#include <linux/interrupt.h>
44#include <linux/tty.h>
Alan Coxe1eaea42010-03-26 11:32:54 +000045#include <linux/ctype.h>
46#include <linux/mm.h>
47#include <linux/string.h>
48#include <linux/slab.h>
49#include <linux/poll.h>
50#include <linux/bitops.h>
51#include <linux/file.h>
52#include <linux/uaccess.h>
53#include <linux/module.h>
54#include <linux/timer.h>
55#include <linux/tty_flip.h>
56#include <linux/tty_driver.h>
57#include <linux/serial.h>
58#include <linux/kfifo.h>
59#include <linux/skbuff.h>
Russ Gorbybcd5abe2011-06-16 14:20:12 -070060#include <net/arp.h>
61#include <linux/ip.h>
62#include <linux/netdevice.h>
63#include <linux/etherdevice.h>
Alan Coxe1eaea42010-03-26 11:32:54 +000064#include <linux/gsmmux.h>
65
66static int debug;
67module_param(debug, int, 0600);
68
Alan Coxa8d12002011-11-08 18:02:10 +000069/* Defaults: these are from the specification */
70
71#define T1 10 /* 100mS */
72#define T2 34 /* 333mS */
73#define N2 3 /* Retry 3 times */
Alan Coxe1eaea42010-03-26 11:32:54 +000074
75/* Use long timers for testing at low speed with debug on */
76#ifdef DEBUG_TIMING
Alan Coxa8d12002011-11-08 18:02:10 +000077#define T1 100
78#define T2 200
Alan Coxe1eaea42010-03-26 11:32:54 +000079#endif
80
Alan Cox5f9a31d2010-11-04 15:17:27 +000081/*
Lucas De Marchi25985ed2011-03-30 22:57:33 -030082 * Semi-arbitrary buffer size limits. 0710 is normally run with 32-64 byte
Alan Cox5f9a31d2010-11-04 15:17:27 +000083 * limits so this is plenty
84 */
Russ Gorbybcd5abe2011-06-16 14:20:12 -070085#define MAX_MRU 1500
86#define MAX_MTU 1500
87#define GSM_NET_TX_TIMEOUT (HZ*10)
88
89/**
90 * struct gsm_mux_net - network interface
91 * @struct gsm_dlci* dlci
92 * @struct net_device_stats stats;
93 *
94 * Created when net interface is initialized.
95 **/
96struct gsm_mux_net {
97 struct kref ref;
98 struct gsm_dlci *dlci;
99 struct net_device_stats stats;
100};
101
102#define STATS(net) (((struct gsm_mux_net *)netdev_priv(net))->stats)
Alan Coxe1eaea42010-03-26 11:32:54 +0000103
104/*
105 * Each block of data we have queued to go out is in the form of
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300106 * a gsm_msg which holds everything we need in a link layer independent
Alan Coxe1eaea42010-03-26 11:32:54 +0000107 * format
108 */
109
110struct gsm_msg {
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;
Chao Bidfabf7f2013-11-26 12:09:39 +0800197 struct mutex mutex;
Russ Gorbyd50f6dc2011-06-14 13:35:32 -0700198 unsigned int num;
Russ Gorby6ab8fba2011-06-16 14:20:13 -0700199 struct kref ref;
Alan Coxe1eaea42010-03-26 11:32:54 +0000200
201 /* Events on the GSM channel */
202 wait_queue_head_t event;
203
204 /* Bits for GSM mode decoding */
205
206 /* Framing Layer */
207 unsigned char *buf;
208 int state;
209#define GSM_SEARCH 0
210#define GSM_START 1
211#define GSM_ADDRESS 2
212#define GSM_CONTROL 3
213#define GSM_LEN 4
214#define GSM_DATA 5
215#define GSM_FCS 6
216#define GSM_OVERRUN 7
Alan Coxc2f2f002010-11-04 15:17:03 +0000217#define GSM_LEN0 8
218#define GSM_LEN1 9
219#define GSM_SSOF 10
Alan Coxe1eaea42010-03-26 11:32:54 +0000220 unsigned int len;
221 unsigned int address;
222 unsigned int count;
223 int escape;
224 int encoding;
225 u8 control;
226 u8 fcs;
Alan Coxc2f2f002010-11-04 15:17:03 +0000227 u8 received_fcs;
Alan Coxe1eaea42010-03-26 11:32:54 +0000228 u8 *txframe; /* TX framing buffer */
229
230 /* Methods for the receiver side */
231 void (*receive)(struct gsm_mux *gsm, u8 ch);
232 void (*error)(struct gsm_mux *gsm, u8 ch, u8 flag);
233 /* And transmit side */
234 int (*output)(struct gsm_mux *mux, u8 *data, int len);
235
236 /* Link Layer */
237 unsigned int mru;
238 unsigned int mtu;
239 int initiator; /* Did we initiate connection */
240 int dead; /* Has the mux been shut down */
241 struct gsm_dlci *dlci[NUM_DLCI];
242 int constipated; /* Asked by remote to shut up */
243
244 spinlock_t tx_lock;
245 unsigned int tx_bytes; /* TX data outstanding */
246#define TX_THRESH_HI 8192
247#define TX_THRESH_LO 2048
Russ Gorbyb4338e12012-08-13 13:44:59 +0100248 struct list_head tx_list; /* Pending data packets */
Alan Coxe1eaea42010-03-26 11:32:54 +0000249
250 /* Control messages */
251 struct timer_list t2_timer; /* Retransmit timer for commands */
252 int cretries; /* Command retry counter */
253 struct gsm_control *pending_cmd;/* Our current pending command */
254 spinlock_t control_lock; /* Protects the pending command */
255
256 /* Configuration */
257 int adaption; /* 1 or 2 supported */
258 u8 ftype; /* UI or UIH */
259 int t1, t2; /* Timers in 1/100th of a sec */
260 int n2; /* Retry count */
261
262 /* Statistics (not currently exposed) */
263 unsigned long bad_fcs;
264 unsigned long malformed;
265 unsigned long io_error;
266 unsigned long bad_size;
267 unsigned long unsupported;
268};
269
270
271/*
272 * Mux objects - needed so that we can translate a tty index into the
273 * relevant mux and DLCI.
274 */
275
276#define MAX_MUX 4 /* 256 minors */
277static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */
278static spinlock_t gsm_mux_lock;
279
Russ Gorbyd50f6dc2011-06-14 13:35:32 -0700280static struct tty_driver *gsm_tty_driver;
281
Alan Coxe1eaea42010-03-26 11:32:54 +0000282/*
283 * This section of the driver logic implements the GSM encodings
284 * both the basic and the 'advanced'. Reliable transport is not
285 * supported.
286 */
287
288#define CR 0x02
289#define EA 0x01
290#define PF 0x10
291
292/* I is special: the rest are ..*/
293#define RR 0x01
294#define UI 0x03
295#define RNR 0x05
296#define REJ 0x09
297#define DM 0x0F
298#define SABM 0x2F
299#define DISC 0x43
300#define UA 0x63
301#define UIH 0xEF
302
303/* Channel commands */
304#define CMD_NSC 0x09
305#define CMD_TEST 0x11
306#define CMD_PSC 0x21
307#define CMD_RLS 0x29
308#define CMD_FCOFF 0x31
309#define CMD_PN 0x41
310#define CMD_RPN 0x49
311#define CMD_FCON 0x51
312#define CMD_CLD 0x61
313#define CMD_SNC 0x69
314#define CMD_MSC 0x71
315
316/* Virtual modem bits */
317#define MDM_FC 0x01
318#define MDM_RTC 0x02
319#define MDM_RTR 0x04
320#define MDM_IC 0x20
321#define MDM_DV 0x40
322
323#define GSM0_SOF 0xF9
Alan Cox5f9a31d2010-11-04 15:17:27 +0000324#define GSM1_SOF 0x7E
Alan Coxe1eaea42010-03-26 11:32:54 +0000325#define GSM1_ESCAPE 0x7D
326#define GSM1_ESCAPE_BITS 0x20
327#define XON 0x11
328#define XOFF 0x13
329
330static const struct tty_port_operations gsm_port_ops;
331
332/*
333 * CRC table for GSM 0710
334 */
335
336static const u8 gsm_fcs8[256] = {
337 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75,
338 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B,
339 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69,
340 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67,
341 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D,
342 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43,
343 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51,
344 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F,
345 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05,
346 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B,
347 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19,
348 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17,
349 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D,
350 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33,
351 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21,
352 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F,
353 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95,
354 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B,
355 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89,
356 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87,
357 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD,
358 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3,
359 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1,
360 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF,
361 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5,
362 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB,
363 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9,
364 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7,
365 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD,
366 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3,
367 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1,
368 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF
369};
370
371#define INIT_FCS 0xFF
372#define GOOD_FCS 0xCF
373
374/**
375 * gsm_fcs_add - update FCS
376 * @fcs: Current FCS
377 * @c: Next data
378 *
379 * Update the FCS to include c. Uses the algorithm in the specification
380 * notes.
381 */
382
383static inline u8 gsm_fcs_add(u8 fcs, u8 c)
384{
385 return gsm_fcs8[fcs ^ c];
386}
387
388/**
389 * gsm_fcs_add_block - update FCS for a block
390 * @fcs: Current FCS
391 * @c: buffer of data
392 * @len: length of buffer
393 *
394 * Update the FCS to include c. Uses the algorithm in the specification
395 * notes.
396 */
397
398static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len)
399{
400 while (len--)
401 fcs = gsm_fcs8[fcs ^ *c++];
402 return fcs;
403}
404
405/**
406 * gsm_read_ea - read a byte into an EA
407 * @val: variable holding value
408 * c: byte going into the EA
409 *
410 * Processes one byte of an EA. Updates the passed variable
411 * and returns 1 if the EA is now completely read
412 */
413
414static int gsm_read_ea(unsigned int *val, u8 c)
415{
416 /* Add the next 7 bits into the value */
417 *val <<= 7;
418 *val |= c >> 1;
419 /* Was this the last byte of the EA 1 = yes*/
420 return c & EA;
421}
422
423/**
424 * gsm_encode_modem - encode modem data bits
425 * @dlci: DLCI to encode from
426 *
427 * Returns the correct GSM encoded modem status bits (6 bit field) for
428 * the current status of the DLCI and attached tty object
429 */
430
431static u8 gsm_encode_modem(const struct gsm_dlci *dlci)
432{
433 u8 modembits = 0;
434 /* FC is true flow control not modem bits */
435 if (dlci->throttled)
436 modembits |= MDM_FC;
437 if (dlci->modem_tx & TIOCM_DTR)
438 modembits |= MDM_RTC;
439 if (dlci->modem_tx & TIOCM_RTS)
440 modembits |= MDM_RTR;
441 if (dlci->modem_tx & TIOCM_RI)
442 modembits |= MDM_IC;
443 if (dlci->modem_tx & TIOCM_CD)
444 modembits |= MDM_DV;
445 return modembits;
446}
447
448/**
449 * gsm_print_packet - display a frame for debug
450 * @hdr: header to print before decode
451 * @addr: address EA from the frame
452 * @cr: C/R bit from the frame
453 * @control: control including PF bit
454 * @data: following data bytes
455 * @dlen: length of data
456 *
457 * Displays a packet in human readable format for debugging purposes. The
458 * style is based on amateur radio LAP-B dump display.
459 */
460
461static void gsm_print_packet(const char *hdr, int addr, int cr,
462 u8 control, const u8 *data, int dlen)
463{
464 if (!(debug & 1))
465 return;
466
Alan Cox5f9a31d2010-11-04 15:17:27 +0000467 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]);
Alan Coxe1eaea42010-03-26 11:32:54 +0000468
469 switch (control & ~PF) {
470 case SABM:
Alan Cox5f9a31d2010-11-04 15:17:27 +0000471 pr_cont("SABM");
Alan Coxe1eaea42010-03-26 11:32:54 +0000472 break;
473 case UA:
Alan Cox5f9a31d2010-11-04 15:17:27 +0000474 pr_cont("UA");
Alan Coxe1eaea42010-03-26 11:32:54 +0000475 break;
476 case DISC:
Alan Cox5f9a31d2010-11-04 15:17:27 +0000477 pr_cont("DISC");
Alan Coxe1eaea42010-03-26 11:32:54 +0000478 break;
479 case DM:
Alan Cox5f9a31d2010-11-04 15:17:27 +0000480 pr_cont("DM");
Alan Coxe1eaea42010-03-26 11:32:54 +0000481 break;
482 case UI:
Alan Cox5f9a31d2010-11-04 15:17:27 +0000483 pr_cont("UI");
Alan Coxe1eaea42010-03-26 11:32:54 +0000484 break;
485 case UIH:
Alan Cox5f9a31d2010-11-04 15:17:27 +0000486 pr_cont("UIH");
Alan Coxe1eaea42010-03-26 11:32:54 +0000487 break;
488 default:
489 if (!(control & 0x01)) {
Alan Cox5f9a31d2010-11-04 15:17:27 +0000490 pr_cont("I N(S)%d N(R)%d",
Alan Cox47fdd642012-09-17 12:02:35 +0100491 (control & 0x0E) >> 1, (control & 0xE0) >> 5);
Alan Coxe1eaea42010-03-26 11:32:54 +0000492 } else switch (control & 0x0F) {
Alan Cox5f9a31d2010-11-04 15:17:27 +0000493 case RR:
494 pr_cont("RR(%d)", (control & 0xE0) >> 5);
495 break;
496 case RNR:
497 pr_cont("RNR(%d)", (control & 0xE0) >> 5);
498 break;
499 case REJ:
500 pr_cont("REJ(%d)", (control & 0xE0) >> 5);
501 break;
502 default:
503 pr_cont("[%02X]", control);
Alan Coxe1eaea42010-03-26 11:32:54 +0000504 }
505 }
506
507 if (control & PF)
Alan Cox5f9a31d2010-11-04 15:17:27 +0000508 pr_cont("(P)");
Alan Coxe1eaea42010-03-26 11:32:54 +0000509 else
Alan Cox5f9a31d2010-11-04 15:17:27 +0000510 pr_cont("(F)");
Alan Coxe1eaea42010-03-26 11:32:54 +0000511
512 if (dlen) {
513 int ct = 0;
514 while (dlen--) {
Alan Cox5f9a31d2010-11-04 15:17:27 +0000515 if (ct % 8 == 0) {
516 pr_cont("\n");
517 pr_debug(" ");
518 }
519 pr_cont("%02X ", *data++);
Alan Coxe1eaea42010-03-26 11:32:54 +0000520 ct++;
521 }
522 }
Alan Cox5f9a31d2010-11-04 15:17:27 +0000523 pr_cont("\n");
Alan Coxe1eaea42010-03-26 11:32:54 +0000524}
525
526
527/*
528 * Link level transmission side
529 */
530
531/**
532 * gsm_stuff_packet - bytestuff a packet
533 * @ibuf: input
534 * @obuf: output
535 * @len: length of input
536 *
537 * Expand a buffer by bytestuffing it. The worst case size change
538 * is doubling and the caller is responsible for handing out
539 * suitable sized buffers.
540 */
541
542static int gsm_stuff_frame(const u8 *input, u8 *output, int len)
543{
544 int olen = 0;
545 while (len--) {
546 if (*input == GSM1_SOF || *input == GSM1_ESCAPE
547 || *input == XON || *input == XOFF) {
548 *output++ = GSM1_ESCAPE;
549 *output++ = *input++ ^ GSM1_ESCAPE_BITS;
550 olen++;
551 } else
552 *output++ = *input++;
553 olen++;
554 }
555 return olen;
556}
557
Alan Coxe1eaea42010-03-26 11:32:54 +0000558/**
559 * gsm_send - send a control frame
560 * @gsm: our GSM mux
561 * @addr: address for control frame
562 * @cr: command/response bit
563 * @control: control byte including PF bit
564 *
565 * Format up and transmit a control frame. These do not go via the
566 * queueing logic as they should be transmitted ahead of data when
567 * they are needed.
568 *
569 * FIXME: Lock versus data TX path
570 */
571
572static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control)
573{
574 int len;
575 u8 cbuf[10];
576 u8 ibuf[3];
577
578 switch (gsm->encoding) {
579 case 0:
580 cbuf[0] = GSM0_SOF;
581 cbuf[1] = (addr << 2) | (cr << 1) | EA;
582 cbuf[2] = control;
583 cbuf[3] = EA; /* Length of data = 0 */
584 cbuf[4] = 0xFF - gsm_fcs_add_block(INIT_FCS, cbuf + 1, 3);
585 cbuf[5] = GSM0_SOF;
586 len = 6;
587 break;
588 case 1:
589 case 2:
590 /* Control frame + packing (but not frame stuffing) in mode 1 */
591 ibuf[0] = (addr << 2) | (cr << 1) | EA;
592 ibuf[1] = control;
593 ibuf[2] = 0xFF - gsm_fcs_add_block(INIT_FCS, ibuf, 2);
594 /* Stuffing may double the size worst case */
595 len = gsm_stuff_frame(ibuf, cbuf + 1, 3);
596 /* Now add the SOF markers */
597 cbuf[0] = GSM1_SOF;
598 cbuf[len + 1] = GSM1_SOF;
599 /* FIXME: we can omit the lead one in many cases */
600 len += 2;
601 break;
602 default:
603 WARN_ON(1);
604 return;
605 }
606 gsm->output(gsm, cbuf, len);
607 gsm_print_packet("-->", addr, cr, control, NULL, 0);
608}
609
610/**
611 * gsm_response - send a control response
612 * @gsm: our GSM mux
613 * @addr: address for control frame
614 * @control: control byte including PF bit
615 *
616 * Format up and transmit a link level response frame.
617 */
618
619static inline void gsm_response(struct gsm_mux *gsm, int addr, int control)
620{
621 gsm_send(gsm, addr, 0, control);
622}
623
624/**
625 * gsm_command - send a control command
626 * @gsm: our GSM mux
627 * @addr: address for control frame
628 * @control: control byte including PF bit
629 *
630 * Format up and transmit a link level command frame.
631 */
632
633static inline void gsm_command(struct gsm_mux *gsm, int addr, int control)
634{
635 gsm_send(gsm, addr, 1, control);
636}
637
638/* Data transmission */
639
640#define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */
641
642/**
643 * gsm_data_alloc - allocate data frame
644 * @gsm: GSM mux
645 * @addr: DLCI address
646 * @len: length excluding header and FCS
647 * @ctrl: control byte
648 *
649 * Allocate a new data buffer for sending frames with data. Space is left
650 * at the front for header bytes but that is treated as an implementation
651 * detail and not for the high level code to use
652 */
653
654static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
655 u8 ctrl)
656{
657 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN,
658 GFP_ATOMIC);
659 if (m == NULL)
660 return NULL;
661 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */
662 m->len = len;
663 m->addr = addr;
664 m->ctrl = ctrl;
Russ Gorbyb4338e12012-08-13 13:44:59 +0100665 INIT_LIST_HEAD(&m->list);
Alan Coxe1eaea42010-03-26 11:32:54 +0000666 return m;
667}
668
669/**
670 * gsm_data_kick - poke the queue
671 * @gsm: GSM Mux
672 *
673 * The tty device has called us to indicate that room has appeared in
674 * the transmit queue. Ram more data into the pipe if we have any
Frederic Beratc01af4f2012-08-13 13:43:58 +0100675 * If we have been flow-stopped by a CMD_FCOFF, then we can only
676 * send messages on DLCI0 until CMD_FCON
Alan Coxe1eaea42010-03-26 11:32:54 +0000677 *
678 * FIXME: lock against link layer control transmissions
679 */
680
681static void gsm_data_kick(struct gsm_mux *gsm)
682{
Russ Gorbyb4338e12012-08-13 13:44:59 +0100683 struct gsm_msg *msg, *nmsg;
Alan Coxe1eaea42010-03-26 11:32:54 +0000684 int len;
685 int skip_sof = 0;
686
Russ Gorbyb4338e12012-08-13 13:44:59 +0100687 list_for_each_entry_safe(msg, nmsg, &gsm->tx_list, list) {
688 if (gsm->constipated && msg->addr)
Frederic Beratc01af4f2012-08-13 13:43:58 +0100689 continue;
Alan Coxe1eaea42010-03-26 11:32:54 +0000690 if (gsm->encoding != 0) {
691 gsm->txframe[0] = GSM1_SOF;
692 len = gsm_stuff_frame(msg->data,
693 gsm->txframe + 1, msg->len);
694 gsm->txframe[len + 1] = GSM1_SOF;
695 len += 2;
696 } else {
697 gsm->txframe[0] = GSM0_SOF;
698 memcpy(gsm->txframe + 1 , msg->data, msg->len);
699 gsm->txframe[msg->len + 1] = GSM0_SOF;
700 len = msg->len + 2;
701 }
702
Joe Perches0a77c4f2011-04-25 16:46:49 -0700703 if (debug & 4)
704 print_hex_dump_bytes("gsm_data_kick: ",
705 DUMP_PREFIX_OFFSET,
706 gsm->txframe, len);
Alan Coxe1eaea42010-03-26 11:32:54 +0000707
708 if (gsm->output(gsm, gsm->txframe + skip_sof,
709 len - skip_sof) < 0)
710 break;
711 /* FIXME: Can eliminate one SOF in many more cases */
Alan Coxe1eaea42010-03-26 11:32:54 +0000712 gsm->tx_bytes -= msg->len;
Alan Coxe1eaea42010-03-26 11:32:54 +0000713 /* For a burst of frames skip the extra SOF within the
714 burst */
715 skip_sof = 1;
Frederic Beratc01af4f2012-08-13 13:43:58 +0100716
Russ Gorbyb4338e12012-08-13 13:44:59 +0100717 list_del(&msg->list);
718 kfree(msg);
Alan Coxe1eaea42010-03-26 11:32:54 +0000719 }
720}
721
722/**
723 * __gsm_data_queue - queue a UI or UIH frame
724 * @dlci: DLCI sending the data
725 * @msg: message queued
726 *
727 * Add data to the transmit queue and try and get stuff moving
728 * out of the mux tty if not already doing so. The Caller must hold
729 * the gsm tx lock.
730 */
731
732static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
733{
734 struct gsm_mux *gsm = dlci->gsm;
735 u8 *dp = msg->data;
736 u8 *fcs = dp + msg->len;
737
738 /* Fill in the header */
739 if (gsm->encoding == 0) {
740 if (msg->len < 128)
741 *--dp = (msg->len << 1) | EA;
742 else {
Ken Millsbe7a7412010-12-13 15:27:27 +0000743 *--dp = (msg->len >> 7); /* bits 7 - 15 */
744 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */
Alan Coxe1eaea42010-03-26 11:32:54 +0000745 }
746 }
747
748 *--dp = msg->ctrl;
749 if (gsm->initiator)
750 *--dp = (msg->addr << 2) | 2 | EA;
751 else
752 *--dp = (msg->addr << 2) | EA;
753 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp);
754 /* Ugly protocol layering violation */
755 if (msg->ctrl == UI || msg->ctrl == (UI|PF))
756 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len);
757 *fcs = 0xFF - *fcs;
758
759 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl,
760 msg->data, msg->len);
761
762 /* Move the header back and adjust the length, also allow for the FCS
763 now tacked on the end */
764 msg->len += (msg->data - dp) + 1;
765 msg->data = dp;
766
767 /* Add to the actual output queue */
Russ Gorbyb4338e12012-08-13 13:44:59 +0100768 list_add_tail(&msg->list, &gsm->tx_list);
Alan Coxe1eaea42010-03-26 11:32:54 +0000769 gsm->tx_bytes += msg->len;
770 gsm_data_kick(gsm);
771}
772
773/**
774 * gsm_data_queue - queue a UI or UIH frame
775 * @dlci: DLCI sending the data
776 * @msg: message queued
777 *
778 * Add data to the transmit queue and try and get stuff moving
779 * out of the mux tty if not already doing so. Take the
780 * the gsm tx lock and dlci lock.
781 */
782
783static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
784{
785 unsigned long flags;
786 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
787 __gsm_data_queue(dlci, msg);
788 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
789}
790
791/**
792 * gsm_dlci_data_output - try and push data out of a DLCI
793 * @gsm: mux
794 * @dlci: the DLCI to pull data from
795 *
796 * Pull data from a DLCI and send it into the transmit queue if there
797 * is data. Keep to the MRU of the mux. This path handles the usual tty
798 * interface which is a byte stream with optional modem data.
799 *
800 * Caller must hold the tx_lock of the mux.
801 */
802
803static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci)
804{
805 struct gsm_msg *msg;
806 u8 *dp;
Mikhail Kshevetskiy268e5262011-09-23 19:22:56 +0400807 int len, total_size, size;
Alan Coxe1eaea42010-03-26 11:32:54 +0000808 int h = dlci->adaption - 1;
809
Mikhail Kshevetskiy268e5262011-09-23 19:22:56 +0400810 total_size = 0;
Aldo Iljazif3c909b2013-07-08 22:28:00 +0300811 while (1) {
Mikhail Kshevetskiy268e5262011-09-23 19:22:56 +0400812 len = kfifo_len(dlci->fifo);
813 if (len == 0)
814 return total_size;
Alan Coxe1eaea42010-03-26 11:32:54 +0000815
Mikhail Kshevetskiy268e5262011-09-23 19:22:56 +0400816 /* MTU/MRU count only the data bits */
817 if (len > gsm->mtu)
818 len = gsm->mtu;
Alan Coxe1eaea42010-03-26 11:32:54 +0000819
Mikhail Kshevetskiy268e5262011-09-23 19:22:56 +0400820 size = len + h;
Alan Coxe1eaea42010-03-26 11:32:54 +0000821
Mikhail Kshevetskiy268e5262011-09-23 19:22:56 +0400822 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
823 /* FIXME: need a timer or something to kick this so it can't
824 get stuck with no work outstanding and no buffer free */
825 if (msg == NULL)
826 return -ENOMEM;
827 dp = msg->data;
828 switch (dlci->adaption) {
829 case 1: /* Unstructured */
830 break;
Aldo Iljazif3c909b2013-07-08 22:28:00 +0300831 case 2: /* Unstructed with modem bits.
832 Always one byte as we never send inline break data */
Mikhail Kshevetskiy268e5262011-09-23 19:22:56 +0400833 *dp++ = gsm_encode_modem(dlci);
834 break;
835 }
836 WARN_ON(kfifo_out_locked(dlci->fifo, dp , len, &dlci->lock) != len);
837 __gsm_data_queue(dlci, msg);
838 total_size += size;
Alan Coxe1eaea42010-03-26 11:32:54 +0000839 }
Alan Coxe1eaea42010-03-26 11:32:54 +0000840 /* Bytes of data we used up */
Mikhail Kshevetskiy268e5262011-09-23 19:22:56 +0400841 return total_size;
Alan Coxe1eaea42010-03-26 11:32:54 +0000842}
843
844/**
845 * gsm_dlci_data_output_framed - try and push data out of a DLCI
846 * @gsm: mux
847 * @dlci: the DLCI to pull data from
848 *
849 * Pull data from a DLCI and send it into the transmit queue if there
850 * is data. Keep to the MRU of the mux. This path handles framed data
851 * queued as skbuffs to the DLCI.
852 *
853 * Caller must hold the tx_lock of the mux.
854 */
855
856static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
857 struct gsm_dlci *dlci)
858{
859 struct gsm_msg *msg;
860 u8 *dp;
861 int len, size;
862 int last = 0, first = 0;
863 int overhead = 0;
864
865 /* One byte per frame is used for B/F flags */
866 if (dlci->adaption == 4)
867 overhead = 1;
868
869 /* dlci->skb is locked by tx_lock */
870 if (dlci->skb == NULL) {
Russ Gorby88ed2a62012-08-13 13:45:30 +0100871 dlci->skb = skb_dequeue_tail(&dlci->skb_list);
Alan Coxe1eaea42010-03-26 11:32:54 +0000872 if (dlci->skb == NULL)
873 return 0;
874 first = 1;
875 }
876 len = dlci->skb->len + overhead;
877
878 /* MTU/MRU count only the data bits */
879 if (len > gsm->mtu) {
880 if (dlci->adaption == 3) {
881 /* Over long frame, bin it */
Russ Gorby329e5672012-08-13 13:45:15 +0100882 dev_kfree_skb_any(dlci->skb);
Alan Coxe1eaea42010-03-26 11:32:54 +0000883 dlci->skb = NULL;
884 return 0;
885 }
886 len = gsm->mtu;
887 } else
888 last = 1;
889
890 size = len + overhead;
891 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
892
893 /* FIXME: need a timer or something to kick this so it can't
894 get stuck with no work outstanding and no buffer free */
Russ Gorby88ed2a62012-08-13 13:45:30 +0100895 if (msg == NULL) {
896 skb_queue_tail(&dlci->skb_list, dlci->skb);
897 dlci->skb = NULL;
Alan Coxe1eaea42010-03-26 11:32:54 +0000898 return -ENOMEM;
Russ Gorby88ed2a62012-08-13 13:45:30 +0100899 }
Alan Coxe1eaea42010-03-26 11:32:54 +0000900 dp = msg->data;
901
902 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */
903 /* Flag byte to carry the start/end info */
904 *dp++ = last << 7 | first << 6 | 1; /* EA */
905 len--;
906 }
Russ Gorby57f21042011-06-14 13:23:29 -0700907 memcpy(dp, dlci->skb->data, len);
908 skb_pull(dlci->skb, len);
Alan Coxe1eaea42010-03-26 11:32:54 +0000909 __gsm_data_queue(dlci, msg);
Russ Gorbybcd5abe2011-06-16 14:20:12 -0700910 if (last) {
Russ Gorby329e5672012-08-13 13:45:15 +0100911 dev_kfree_skb_any(dlci->skb);
Alan Coxe1eaea42010-03-26 11:32:54 +0000912 dlci->skb = NULL;
Russ Gorbybcd5abe2011-06-16 14:20:12 -0700913 }
Alan Coxe1eaea42010-03-26 11:32:54 +0000914 return size;
915}
916
917/**
918 * gsm_dlci_data_sweep - look for data to send
919 * @gsm: the GSM mux
920 *
921 * Sweep the GSM mux channels in priority order looking for ones with
922 * data to send. We could do with optimising this scan a bit. We aim
923 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit
924 * TX_THRESH_LO we get called again
925 *
926 * FIXME: We should round robin between groups and in theory you can
927 * renegotiate DLCI priorities with optional stuff. Needs optimising.
928 */
929
930static void gsm_dlci_data_sweep(struct gsm_mux *gsm)
931{
932 int len;
933 /* Priority ordering: We should do priority with RR of the groups */
934 int i = 1;
Alan Coxe1eaea42010-03-26 11:32:54 +0000935
Alan Coxe1eaea42010-03-26 11:32:54 +0000936 while (i < NUM_DLCI) {
937 struct gsm_dlci *dlci;
938
939 if (gsm->tx_bytes > TX_THRESH_HI)
940 break;
941 dlci = gsm->dlci[i];
942 if (dlci == NULL || dlci->constipated) {
943 i++;
944 continue;
945 }
Russ Gorbybcd5abe2011-06-16 14:20:12 -0700946 if (dlci->adaption < 3 && !dlci->net)
Alan Coxe1eaea42010-03-26 11:32:54 +0000947 len = gsm_dlci_data_output(gsm, dlci);
948 else
949 len = gsm_dlci_data_output_framed(gsm, dlci);
950 if (len < 0)
Julia Lawalle73790a2010-08-10 18:03:12 -0700951 break;
Alan Coxe1eaea42010-03-26 11:32:54 +0000952 /* DLCI empty - try the next */
953 if (len == 0)
954 i++;
955 }
Alan Coxe1eaea42010-03-26 11:32:54 +0000956}
957
958/**
959 * gsm_dlci_data_kick - transmit if possible
960 * @dlci: DLCI to kick
961 *
962 * Transmit data from this DLCI if the queue is empty. We can't rely on
963 * a tty wakeup except when we filled the pipe so we need to fire off
964 * new data ourselves in other cases.
965 */
966
967static void gsm_dlci_data_kick(struct gsm_dlci *dlci)
968{
969 unsigned long flags;
Russ Gorby192b6042012-08-13 13:43:36 +0100970 int sweep;
Alan Coxe1eaea42010-03-26 11:32:54 +0000971
Aldo Iljazif3c909b2013-07-08 22:28:00 +0300972 if (dlci->constipated)
Frederic Beratc01af4f2012-08-13 13:43:58 +0100973 return;
Frederic Beratc01af4f2012-08-13 13:43:58 +0100974
Alan Coxe1eaea42010-03-26 11:32:54 +0000975 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
976 /* If we have nothing running then we need to fire up */
Russ Gorby192b6042012-08-13 13:43:36 +0100977 sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO);
Russ Gorbybcd5abe2011-06-16 14:20:12 -0700978 if (dlci->gsm->tx_bytes == 0) {
979 if (dlci->net)
980 gsm_dlci_data_output_framed(dlci->gsm, dlci);
981 else
982 gsm_dlci_data_output(dlci->gsm, dlci);
Russ Gorby192b6042012-08-13 13:43:36 +0100983 }
984 if (sweep)
Aldo Iljazif3c909b2013-07-08 22:28:00 +0300985 gsm_dlci_data_sweep(dlci->gsm);
Alan Coxe1eaea42010-03-26 11:32:54 +0000986 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
987}
988
989/*
990 * Control message processing
991 */
992
993
994/**
995 * gsm_control_reply - send a response frame to a control
996 * @gsm: gsm channel
997 * @cmd: the command to use
998 * @data: data to follow encoded info
999 * @dlen: length of data
1000 *
1001 * Encode up and queue a UI/UIH frame containing our response.
1002 */
1003
1004static void gsm_control_reply(struct gsm_mux *gsm, int cmd, u8 *data,
1005 int dlen)
1006{
1007 struct gsm_msg *msg;
1008 msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype);
Ken Mills093d8042010-12-13 15:28:03 +00001009 if (msg == NULL)
1010 return;
Alan Coxe1eaea42010-03-26 11:32:54 +00001011 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */
1012 msg->data[1] = (dlen << 1) | EA;
1013 memcpy(msg->data + 2, data, dlen);
1014 gsm_data_queue(gsm->dlci[0], msg);
1015}
1016
1017/**
1018 * gsm_process_modem - process received modem status
1019 * @tty: virtual tty bound to the DLCI
1020 * @dlci: DLCI to affect
1021 * @modem: modem bits (full EA)
1022 *
1023 * Used when a modem control message or line state inline in adaption
1024 * layer 2 is processed. Sort out the local modem state and throttles
1025 */
1026
1027static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
Russ Gorby72632872011-06-14 13:23:28 -07001028 u32 modem, int clen)
Alan Coxe1eaea42010-03-26 11:32:54 +00001029{
1030 int mlines = 0;
Russ Gorby72632872011-06-14 13:23:28 -07001031 u8 brk = 0;
Frederic Beratc01af4f2012-08-13 13:43:58 +01001032 int fc;
Russ Gorby72632872011-06-14 13:23:28 -07001033
1034 /* The modem status command can either contain one octet (v.24 signals)
1035 or two octets (v.24 signals + break signals). The length field will
1036 either be 2 or 3 respectively. This is specified in section
1037 5.4.6.3.7 of the 27.010 mux spec. */
1038
1039 if (clen == 2)
1040 modem = modem & 0x7f;
1041 else {
1042 brk = modem & 0x7f;
1043 modem = (modem >> 7) & 0x7f;
Frederic Beratc01af4f2012-08-13 13:43:58 +01001044 }
Alan Coxe1eaea42010-03-26 11:32:54 +00001045
1046 /* Flow control/ready to communicate */
Frederic Beratc01af4f2012-08-13 13:43:58 +01001047 fc = (modem & MDM_FC) || !(modem & MDM_RTR);
1048 if (fc && !dlci->constipated) {
Alan Coxe1eaea42010-03-26 11:32:54 +00001049 /* Need to throttle our output on this device */
1050 dlci->constipated = 1;
Frederic Beratc01af4f2012-08-13 13:43:58 +01001051 } else if (!fc && dlci->constipated) {
Alan Coxe1eaea42010-03-26 11:32:54 +00001052 dlci->constipated = 0;
1053 gsm_dlci_data_kick(dlci);
1054 }
Frederic Beratc01af4f2012-08-13 13:43:58 +01001055
Alan Coxe1eaea42010-03-26 11:32:54 +00001056 /* Map modem bits */
Frederic Beratc01af4f2012-08-13 13:43:58 +01001057 if (modem & MDM_RTC)
1058 mlines |= TIOCM_DSR | TIOCM_DTR;
Alan Coxe1eaea42010-03-26 11:32:54 +00001059 if (modem & MDM_RTR)
1060 mlines |= TIOCM_RTS | TIOCM_CTS;
1061 if (modem & MDM_IC)
1062 mlines |= TIOCM_RI;
1063 if (modem & MDM_DV)
1064 mlines |= TIOCM_CD;
1065
1066 /* Carrier drop -> hangup */
1067 if (tty) {
1068 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD))
Alan Coxadc8d742012-07-14 15:31:47 +01001069 if (!(tty->termios.c_cflag & CLOCAL))
Alan Coxe1eaea42010-03-26 11:32:54 +00001070 tty_hangup(tty);
Alan Coxe1eaea42010-03-26 11:32:54 +00001071 }
Jiri Slaby92a19f92013-01-03 15:53:03 +01001072 if (brk & 0x01)
1073 tty_insert_flip_char(&dlci->port, 0, TTY_BREAK);
Alan Coxe1eaea42010-03-26 11:32:54 +00001074 dlci->modem_rx = mlines;
1075}
1076
1077/**
1078 * gsm_control_modem - modem status received
1079 * @gsm: GSM channel
1080 * @data: data following command
1081 * @clen: command length
1082 *
1083 * We have received a modem status control message. This is used by
1084 * the GSM mux protocol to pass virtual modem line status and optionally
1085 * to indicate break signals. Unpack it, convert to Linux representation
1086 * and if need be stuff a break message down the tty.
1087 */
1088
1089static void gsm_control_modem(struct gsm_mux *gsm, u8 *data, int clen)
1090{
1091 unsigned int addr = 0;
1092 unsigned int modem = 0;
Lars Poeschel3ac06b92014-01-07 13:34:37 +01001093 unsigned int brk = 0;
Alan Coxe1eaea42010-03-26 11:32:54 +00001094 struct gsm_dlci *dlci;
1095 int len = clen;
1096 u8 *dp = data;
1097 struct tty_struct *tty;
1098
1099 while (gsm_read_ea(&addr, *dp++) == 0) {
1100 len--;
1101 if (len == 0)
1102 return;
1103 }
1104 /* Must be at least one byte following the EA */
1105 len--;
1106 if (len <= 0)
1107 return;
1108
1109 addr >>= 1;
1110 /* Closed port, or invalid ? */
1111 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1112 return;
1113 dlci = gsm->dlci[addr];
1114
1115 while (gsm_read_ea(&modem, *dp++) == 0) {
1116 len--;
1117 if (len == 0)
1118 return;
1119 }
Lars Poeschel3ac06b92014-01-07 13:34:37 +01001120 len--;
1121 if (len > 0) {
1122 while (gsm_read_ea(&brk, *dp++) == 0) {
1123 len--;
1124 if (len == 0)
1125 return;
1126 }
1127 modem <<= 7;
1128 modem |= (brk & 0x7f);
1129 }
Alan Coxe1eaea42010-03-26 11:32:54 +00001130 tty = tty_port_tty_get(&dlci->port);
Russ Gorby72632872011-06-14 13:23:28 -07001131 gsm_process_modem(tty, dlci, modem, clen);
Alan Coxe1eaea42010-03-26 11:32:54 +00001132 if (tty) {
1133 tty_wakeup(tty);
1134 tty_kref_put(tty);
1135 }
1136 gsm_control_reply(gsm, CMD_MSC, data, clen);
1137}
1138
1139/**
1140 * gsm_control_rls - remote line status
1141 * @gsm: GSM channel
1142 * @data: data bytes
1143 * @clen: data length
1144 *
1145 * The modem sends us a two byte message on the control channel whenever
1146 * it wishes to send us an error state from the virtual link. Stuff
1147 * this into the uplink tty if present
1148 */
1149
1150static void gsm_control_rls(struct gsm_mux *gsm, u8 *data, int clen)
1151{
Jiri Slaby92a19f92013-01-03 15:53:03 +01001152 struct tty_port *port;
Aldo Iljazif3c909b2013-07-08 22:28:00 +03001153 unsigned int addr = 0;
Alan Coxe1eaea42010-03-26 11:32:54 +00001154 u8 bits;
1155 int len = clen;
1156 u8 *dp = data;
1157
1158 while (gsm_read_ea(&addr, *dp++) == 0) {
1159 len--;
1160 if (len == 0)
1161 return;
1162 }
1163 /* Must be at least one byte following ea */
1164 len--;
1165 if (len <= 0)
1166 return;
1167 addr >>= 1;
1168 /* Closed port, or invalid ? */
1169 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1170 return;
1171 /* No error ? */
1172 bits = *dp;
1173 if ((bits & 1) == 0)
1174 return;
Alan Coxe1eaea42010-03-26 11:32:54 +00001175
Jiri Slaby92a19f92013-01-03 15:53:03 +01001176 port = &gsm->dlci[addr]->port;
1177
1178 if (bits & 2)
1179 tty_insert_flip_char(port, 0, TTY_OVERRUN);
1180 if (bits & 4)
1181 tty_insert_flip_char(port, 0, TTY_PARITY);
1182 if (bits & 8)
1183 tty_insert_flip_char(port, 0, TTY_FRAME);
1184
Jiri Slaby2e124b42013-01-03 15:53:06 +01001185 tty_flip_buffer_push(port);
1186
Alan Coxe1eaea42010-03-26 11:32:54 +00001187 gsm_control_reply(gsm, CMD_RLS, data, clen);
1188}
1189
1190static void gsm_dlci_begin_close(struct gsm_dlci *dlci);
1191
1192/**
1193 * gsm_control_message - DLCI 0 control processing
1194 * @gsm: our GSM mux
1195 * @command: the command EA
1196 * @data: data beyond the command/length EAs
1197 * @clen: length
1198 *
1199 * Input processor for control messages from the other end of the link.
1200 * Processes the incoming request and queues a response frame or an
1201 * NSC response if not supported
1202 */
1203
1204static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
1205 u8 *data, int clen)
1206{
1207 u8 buf[1];
Russ Gorby5e447082012-08-13 13:44:40 +01001208 unsigned long flags;
1209
Alan Coxe1eaea42010-03-26 11:32:54 +00001210 switch (command) {
1211 case CMD_CLD: {
1212 struct gsm_dlci *dlci = gsm->dlci[0];
1213 /* Modem wishes to close down */
1214 if (dlci) {
1215 dlci->dead = 1;
1216 gsm->dead = 1;
1217 gsm_dlci_begin_close(dlci);
1218 }
1219 }
1220 break;
1221 case CMD_TEST:
1222 /* Modem wishes to test, reply with the data */
1223 gsm_control_reply(gsm, CMD_TEST, data, clen);
1224 break;
1225 case CMD_FCON:
Alan Coxe1eaea42010-03-26 11:32:54 +00001226 /* Modem can accept data again */
1227 gsm->constipated = 0;
Frederic Beratc01af4f2012-08-13 13:43:58 +01001228 gsm_control_reply(gsm, CMD_FCON, NULL, 0);
Alan Coxe1eaea42010-03-26 11:32:54 +00001229 /* Kick the link in case it is idling */
Russ Gorby5e447082012-08-13 13:44:40 +01001230 spin_lock_irqsave(&gsm->tx_lock, flags);
Alan Coxe1eaea42010-03-26 11:32:54 +00001231 gsm_data_kick(gsm);
Russ Gorby5e447082012-08-13 13:44:40 +01001232 spin_unlock_irqrestore(&gsm->tx_lock, flags);
Alan Coxe1eaea42010-03-26 11:32:54 +00001233 break;
Frederic Beratc01af4f2012-08-13 13:43:58 +01001234 case CMD_FCOFF:
1235 /* Modem wants us to STFU */
Frederic Beratc01af4f2012-08-13 13:43:58 +01001236 gsm->constipated = 1;
1237 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0);
1238 break;
Alan Coxe1eaea42010-03-26 11:32:54 +00001239 case CMD_MSC:
1240 /* Out of band modem line change indicator for a DLCI */
1241 gsm_control_modem(gsm, data, clen);
1242 break;
1243 case CMD_RLS:
1244 /* Out of band error reception for a DLCI */
1245 gsm_control_rls(gsm, data, clen);
1246 break;
1247 case CMD_PSC:
1248 /* Modem wishes to enter power saving state */
1249 gsm_control_reply(gsm, CMD_PSC, NULL, 0);
1250 break;
1251 /* Optional unsupported commands */
1252 case CMD_PN: /* Parameter negotiation */
Lucas De Marchi25985ed2011-03-30 22:57:33 -03001253 case CMD_RPN: /* Remote port negotiation */
1254 case CMD_SNC: /* Service negotiation command */
Alan Coxe1eaea42010-03-26 11:32:54 +00001255 default:
1256 /* Reply to bad commands with an NSC */
1257 buf[0] = command;
1258 gsm_control_reply(gsm, CMD_NSC, buf, 1);
1259 break;
1260 }
1261}
1262
1263/**
1264 * gsm_control_response - process a response to our control
1265 * @gsm: our GSM mux
1266 * @command: the command (response) EA
1267 * @data: data beyond the command/length EA
1268 * @clen: length
1269 *
1270 * Process a response to an outstanding command. We only allow a single
1271 * control message in flight so this is fairly easy. All the clean up
1272 * is done by the caller, we just update the fields, flag it as done
1273 * and return
1274 */
1275
1276static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
1277 u8 *data, int clen)
1278{
1279 struct gsm_control *ctrl;
1280 unsigned long flags;
1281
1282 spin_lock_irqsave(&gsm->control_lock, flags);
1283
1284 ctrl = gsm->pending_cmd;
1285 /* Does the reply match our command */
1286 command |= 1;
1287 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) {
1288 /* Our command was replied to, kill the retry timer */
1289 del_timer(&gsm->t2_timer);
1290 gsm->pending_cmd = NULL;
1291 /* Rejected by the other end */
1292 if (command == CMD_NSC)
1293 ctrl->error = -EOPNOTSUPP;
1294 ctrl->done = 1;
1295 wake_up(&gsm->event);
1296 }
1297 spin_unlock_irqrestore(&gsm->control_lock, flags);
1298}
1299
1300/**
Alan Cox5f9a31d2010-11-04 15:17:27 +00001301 * gsm_control_transmit - send control packet
Alan Coxe1eaea42010-03-26 11:32:54 +00001302 * @gsm: gsm mux
1303 * @ctrl: frame to send
1304 *
1305 * Send out a pending control command (called under control lock)
1306 */
1307
1308static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl)
1309{
Eric Bénarded43b472011-03-09 19:24:49 +01001310 struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, gsm->ftype);
Alan Coxe1eaea42010-03-26 11:32:54 +00001311 if (msg == NULL)
1312 return;
1313 msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */
1314 memcpy(msg->data + 1, ctrl->data, ctrl->len);
1315 gsm_data_queue(gsm->dlci[0], msg);
1316}
1317
1318/**
1319 * gsm_control_retransmit - retransmit a control frame
1320 * @data: pointer to our gsm object
1321 *
1322 * Called off the T2 timer expiry in order to retransmit control frames
1323 * that have been lost in the system somewhere. The control_lock protects
1324 * us from colliding with another sender or a receive completion event.
1325 * In that situation the timer may still occur in a small window but
1326 * gsm->pending_cmd will be NULL and we just let the timer expire.
1327 */
1328
1329static void gsm_control_retransmit(unsigned long data)
1330{
1331 struct gsm_mux *gsm = (struct gsm_mux *)data;
1332 struct gsm_control *ctrl;
1333 unsigned long flags;
1334 spin_lock_irqsave(&gsm->control_lock, flags);
1335 ctrl = gsm->pending_cmd;
1336 if (ctrl) {
1337 gsm->cretries--;
1338 if (gsm->cretries == 0) {
1339 gsm->pending_cmd = NULL;
1340 ctrl->error = -ETIMEDOUT;
1341 ctrl->done = 1;
1342 spin_unlock_irqrestore(&gsm->control_lock, flags);
1343 wake_up(&gsm->event);
1344 return;
1345 }
1346 gsm_control_transmit(gsm, ctrl);
1347 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1348 }
1349 spin_unlock_irqrestore(&gsm->control_lock, flags);
1350}
1351
1352/**
1353 * gsm_control_send - send a control frame on DLCI 0
1354 * @gsm: the GSM channel
1355 * @command: command to send including CR bit
1356 * @data: bytes of data (must be kmalloced)
1357 * @len: length of the block to send
1358 *
1359 * Queue and dispatch a control command. Only one command can be
1360 * active at a time. In theory more can be outstanding but the matching
1361 * gets really complicated so for now stick to one outstanding.
1362 */
1363
1364static struct gsm_control *gsm_control_send(struct gsm_mux *gsm,
1365 unsigned int command, u8 *data, int clen)
1366{
1367 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control),
1368 GFP_KERNEL);
1369 unsigned long flags;
1370 if (ctrl == NULL)
1371 return NULL;
1372retry:
1373 wait_event(gsm->event, gsm->pending_cmd == NULL);
1374 spin_lock_irqsave(&gsm->control_lock, flags);
1375 if (gsm->pending_cmd != NULL) {
1376 spin_unlock_irqrestore(&gsm->control_lock, flags);
1377 goto retry;
1378 }
1379 ctrl->cmd = command;
1380 ctrl->data = data;
1381 ctrl->len = clen;
1382 gsm->pending_cmd = ctrl;
1383 gsm->cretries = gsm->n2;
1384 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1385 gsm_control_transmit(gsm, ctrl);
1386 spin_unlock_irqrestore(&gsm->control_lock, flags);
1387 return ctrl;
1388}
1389
1390/**
1391 * gsm_control_wait - wait for a control to finish
1392 * @gsm: GSM mux
1393 * @control: control we are waiting on
1394 *
1395 * Waits for the control to complete or time out. Frees any used
1396 * resources and returns 0 for success, or an error if the remote
1397 * rejected or ignored the request.
1398 */
1399
1400static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
1401{
1402 int err;
1403 wait_event(gsm->event, control->done == 1);
1404 err = control->error;
1405 kfree(control);
1406 return err;
1407}
1408
1409
1410/*
1411 * DLCI level handling: Needs krefs
1412 */
1413
1414/*
1415 * State transitions and timers
1416 */
1417
1418/**
1419 * gsm_dlci_close - a DLCI has closed
1420 * @dlci: DLCI that closed
1421 *
1422 * Perform processing when moving a DLCI into closed state. If there
1423 * is an attached tty this is hung up
1424 */
1425
1426static void gsm_dlci_close(struct gsm_dlci *dlci)
1427{
1428 del_timer(&dlci->t1);
1429 if (debug & 8)
Alan Cox5f9a31d2010-11-04 15:17:27 +00001430 pr_debug("DLCI %d goes closed.\n", dlci->addr);
Alan Coxe1eaea42010-03-26 11:32:54 +00001431 dlci->state = DLCI_CLOSED;
1432 if (dlci->addr != 0) {
Jiri Slabyaa27a092013-03-07 13:12:30 +01001433 tty_port_tty_hangup(&dlci->port, false);
Alan Coxe1eaea42010-03-26 11:32:54 +00001434 kfifo_reset(dlci->fifo);
1435 } else
1436 dlci->gsm->dead = 1;
1437 wake_up(&dlci->gsm->event);
1438 /* A DLCI 0 close is a MUX termination so we need to kick that
1439 back to userspace somehow */
1440}
1441
1442/**
1443 * gsm_dlci_open - a DLCI has opened
1444 * @dlci: DLCI that opened
1445 *
1446 * Perform processing when moving a DLCI into open state.
1447 */
1448
1449static void gsm_dlci_open(struct gsm_dlci *dlci)
1450{
1451 /* Note that SABM UA .. SABM UA first UA lost can mean that we go
1452 open -> open */
1453 del_timer(&dlci->t1);
1454 /* This will let a tty open continue */
1455 dlci->state = DLCI_OPEN;
1456 if (debug & 8)
Alan Cox5f9a31d2010-11-04 15:17:27 +00001457 pr_debug("DLCI %d goes open.\n", dlci->addr);
Alan Coxe1eaea42010-03-26 11:32:54 +00001458 wake_up(&dlci->gsm->event);
1459}
1460
1461/**
1462 * gsm_dlci_t1 - T1 timer expiry
1463 * @dlci: DLCI that opened
1464 *
1465 * The T1 timer handles retransmits of control frames (essentially of
1466 * SABM and DISC). We resend the command until the retry count runs out
1467 * in which case an opening port goes back to closed and a closing port
1468 * is simply put into closed state (any further frames from the other
1469 * end will get a DM response)
1470 */
1471
1472static void gsm_dlci_t1(unsigned long data)
1473{
1474 struct gsm_dlci *dlci = (struct gsm_dlci *)data;
1475 struct gsm_mux *gsm = dlci->gsm;
1476
1477 switch (dlci->state) {
1478 case DLCI_OPENING:
1479 dlci->retries--;
1480 if (dlci->retries) {
1481 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1482 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1483 } else
1484 gsm_dlci_close(dlci);
1485 break;
1486 case DLCI_CLOSING:
1487 dlci->retries--;
1488 if (dlci->retries) {
1489 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1490 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1491 } else
1492 gsm_dlci_close(dlci);
1493 break;
1494 }
1495}
1496
1497/**
1498 * gsm_dlci_begin_open - start channel open procedure
1499 * @dlci: DLCI to open
1500 *
1501 * Commence opening a DLCI from the Linux side. We issue SABM messages
1502 * to the modem which should then reply with a UA, at which point we
1503 * will move into open state. Opening is done asynchronously with retry
1504 * running off timers and the responses.
1505 */
1506
1507static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
1508{
1509 struct gsm_mux *gsm = dlci->gsm;
1510 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING)
1511 return;
1512 dlci->retries = gsm->n2;
1513 dlci->state = DLCI_OPENING;
1514 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1515 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1516}
1517
1518/**
1519 * gsm_dlci_begin_close - start channel open procedure
1520 * @dlci: DLCI to open
1521 *
1522 * Commence closing a DLCI from the Linux side. We issue DISC messages
1523 * to the modem which should then reply with a UA, at which point we
1524 * will move into closed state. Closing is done asynchronously with retry
1525 * off timers. We may also receive a DM reply from the other end which
1526 * indicates the channel was already closed.
1527 */
1528
1529static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
1530{
1531 struct gsm_mux *gsm = dlci->gsm;
1532 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
1533 return;
1534 dlci->retries = gsm->n2;
1535 dlci->state = DLCI_CLOSING;
1536 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1537 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1538}
1539
1540/**
1541 * gsm_dlci_data - data arrived
1542 * @dlci: channel
1543 * @data: block of bytes received
1544 * @len: length of received block
1545 *
1546 * A UI or UIH frame has arrived which contains data for a channel
1547 * other than the control channel. If the relevant virtual tty is
1548 * open we shovel the bits down it, if not we drop them.
1549 */
1550
Russ Gorby72632872011-06-14 13:23:28 -07001551static void gsm_dlci_data(struct gsm_dlci *dlci, u8 *data, int clen)
Alan Coxe1eaea42010-03-26 11:32:54 +00001552{
1553 /* krefs .. */
1554 struct tty_port *port = &dlci->port;
Jiri Slaby2e124b42013-01-03 15:53:06 +01001555 struct tty_struct *tty;
Alan Coxe1eaea42010-03-26 11:32:54 +00001556 unsigned int modem = 0;
Russ Gorby72632872011-06-14 13:23:28 -07001557 int len = clen;
Alan Coxe1eaea42010-03-26 11:32:54 +00001558
1559 if (debug & 16)
Jiri Slaby2e124b42013-01-03 15:53:06 +01001560 pr_debug("%d bytes for tty\n", len);
1561 switch (dlci->adaption) {
1562 /* Unsupported types */
1563 /* Packetised interruptible data */
1564 case 4:
1565 break;
1566 /* Packetised uininterruptible voice/data */
1567 case 3:
1568 break;
1569 /* Asynchronous serial with line state in each frame */
1570 case 2:
1571 while (gsm_read_ea(&modem, *data++) == 0) {
1572 len--;
1573 if (len == 0)
1574 return;
Alan Coxe1eaea42010-03-26 11:32:54 +00001575 }
Jiri Slaby2e124b42013-01-03 15:53:06 +01001576 tty = tty_port_tty_get(port);
1577 if (tty) {
1578 gsm_process_modem(tty, dlci, modem, clen);
1579 tty_kref_put(tty);
1580 }
1581 /* Line state will go via DLCI 0 controls only */
1582 case 1:
1583 default:
1584 tty_insert_flip_string(port, data, len);
1585 tty_flip_buffer_push(port);
Alan Coxe1eaea42010-03-26 11:32:54 +00001586 }
1587}
1588
1589/**
1590 * gsm_dlci_control - data arrived on control channel
1591 * @dlci: channel
1592 * @data: block of bytes received
1593 * @len: length of received block
1594 *
1595 * A UI or UIH frame has arrived which contains data for DLCI 0 the
1596 * control channel. This should contain a command EA followed by
1597 * control data bytes. The command EA contains a command/response bit
1598 * and we divide up the work accordingly.
1599 */
1600
1601static void gsm_dlci_command(struct gsm_dlci *dlci, u8 *data, int len)
1602{
1603 /* See what command is involved */
1604 unsigned int command = 0;
1605 while (len-- > 0) {
1606 if (gsm_read_ea(&command, *data++) == 1) {
1607 int clen = *data++;
1608 len--;
1609 /* FIXME: this is properly an EA */
1610 clen >>= 1;
1611 /* Malformed command ? */
1612 if (clen > len)
1613 return;
1614 if (command & 1)
1615 gsm_control_message(dlci->gsm, command,
1616 data, clen);
1617 else
1618 gsm_control_response(dlci->gsm, command,
1619 data, clen);
1620 return;
1621 }
1622 }
1623}
1624
1625/*
1626 * Allocate/Free DLCI channels
1627 */
1628
1629/**
1630 * gsm_dlci_alloc - allocate a DLCI
1631 * @gsm: GSM mux
1632 * @addr: address of the DLCI
1633 *
1634 * Allocate and install a new DLCI object into the GSM mux.
1635 *
1636 * FIXME: review locking races
1637 */
1638
1639static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
1640{
1641 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC);
1642 if (dlci == NULL)
1643 return NULL;
1644 spin_lock_init(&dlci->lock);
Russ Gorbybcd5abe2011-06-16 14:20:12 -07001645 mutex_init(&dlci->mutex);
Alan Coxe1eaea42010-03-26 11:32:54 +00001646 dlci->fifo = &dlci->_fifo;
1647 if (kfifo_alloc(&dlci->_fifo, 4096, GFP_KERNEL) < 0) {
1648 kfree(dlci);
1649 return NULL;
1650 }
1651
1652 skb_queue_head_init(&dlci->skb_list);
1653 init_timer(&dlci->t1);
1654 dlci->t1.function = gsm_dlci_t1;
1655 dlci->t1.data = (unsigned long)dlci;
1656 tty_port_init(&dlci->port);
1657 dlci->port.ops = &gsm_port_ops;
1658 dlci->gsm = gsm;
1659 dlci->addr = addr;
1660 dlci->adaption = gsm->adaption;
1661 dlci->state = DLCI_CLOSED;
1662 if (addr)
1663 dlci->data = gsm_dlci_data;
1664 else
1665 dlci->data = gsm_dlci_command;
1666 gsm->dlci[addr] = dlci;
1667 return dlci;
1668}
1669
1670/**
Russ Gorby6ab8fba2011-06-16 14:20:13 -07001671 * gsm_dlci_free - free DLCI
1672 * @dlci: DLCI to free
Alan Coxe1eaea42010-03-26 11:32:54 +00001673 *
Russ Gorby6ab8fba2011-06-16 14:20:13 -07001674 * Free up a DLCI.
Alan Coxe1eaea42010-03-26 11:32:54 +00001675 *
1676 * Can sleep.
1677 */
Jiri Slaby9a8e62b2012-11-15 09:49:53 +01001678static void gsm_dlci_free(struct tty_port *port)
Russ Gorby6ab8fba2011-06-16 14:20:13 -07001679{
Jiri Slaby9a8e62b2012-11-15 09:49:53 +01001680 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
Russ Gorby6ab8fba2011-06-16 14:20:13 -07001681
1682 del_timer_sync(&dlci->t1);
1683 dlci->gsm->dlci[dlci->addr] = NULL;
1684 kfifo_free(dlci->fifo);
1685 while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
Russ Gorby329e5672012-08-13 13:45:15 +01001686 dev_kfree_skb(dlci->skb);
Russ Gorby6ab8fba2011-06-16 14:20:13 -07001687 kfree(dlci);
1688}
1689
1690static inline void dlci_get(struct gsm_dlci *dlci)
1691{
Jiri Slaby9a8e62b2012-11-15 09:49:53 +01001692 tty_port_get(&dlci->port);
Russ Gorby6ab8fba2011-06-16 14:20:13 -07001693}
1694
1695static inline void dlci_put(struct gsm_dlci *dlci)
1696{
Jiri Slaby9a8e62b2012-11-15 09:49:53 +01001697 tty_port_put(&dlci->port);
Russ Gorby6ab8fba2011-06-16 14:20:13 -07001698}
1699
Dirkjan Bussink4d9b1092013-01-30 11:44:50 +01001700static void gsm_destroy_network(struct gsm_dlci *dlci);
1701
Russ Gorby6ab8fba2011-06-16 14:20:13 -07001702/**
1703 * gsm_dlci_release - release DLCI
1704 * @dlci: DLCI to destroy
1705 *
1706 * Release a DLCI. Actual free is deferred until either
1707 * mux is closed or tty is closed - whichever is last.
1708 *
1709 * Can sleep.
1710 */
1711static void gsm_dlci_release(struct gsm_dlci *dlci)
Alan Coxe1eaea42010-03-26 11:32:54 +00001712{
1713 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1714 if (tty) {
Dirkjan Bussink4d9b1092013-01-30 11:44:50 +01001715 mutex_lock(&dlci->mutex);
1716 gsm_destroy_network(dlci);
1717 mutex_unlock(&dlci->mutex);
1718
Alan Coxe1eaea42010-03-26 11:32:54 +00001719 tty_vhangup(tty);
Chuansheng Liube706572013-12-18 13:30:11 +08001720
Dirkjan Bussink4d9b1092013-01-30 11:44:50 +01001721 tty_port_tty_set(&dlci->port, NULL);
Alan Coxe1eaea42010-03-26 11:32:54 +00001722 tty_kref_put(tty);
1723 }
Dirkjan Bussink4d9b1092013-01-30 11:44:50 +01001724 dlci->state = DLCI_CLOSED;
Russ Gorby6ab8fba2011-06-16 14:20:13 -07001725 dlci_put(dlci);
Alan Coxe1eaea42010-03-26 11:32:54 +00001726}
1727
Alan Coxe1eaea42010-03-26 11:32:54 +00001728/*
1729 * LAPBish link layer logic
1730 */
1731
1732/**
1733 * gsm_queue - a GSM frame is ready to process
1734 * @gsm: pointer to our gsm mux
1735 *
1736 * At this point in time a frame has arrived and been demangled from
1737 * the line encoding. All the differences between the encodings have
1738 * been handled below us and the frame is unpacked into the structures.
1739 * The fcs holds the header FCS but any data FCS must be added here.
1740 */
1741
1742static void gsm_queue(struct gsm_mux *gsm)
1743{
1744 struct gsm_dlci *dlci;
1745 u8 cr;
1746 int address;
1747 /* We have to sneak a look at the packet body to do the FCS.
1748 A somewhat layering violation in the spec */
1749
1750 if ((gsm->control & ~PF) == UI)
1751 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len);
Aldo Iljazif3c909b2013-07-08 22:28:00 +03001752 if (gsm->encoding == 0) {
1753 /* WARNING: gsm->received_fcs is used for
1754 gsm->encoding = 0 only.
1755 In this case it contain the last piece of data
1756 required to generate final CRC */
Mikhail Kshevetskiy9db4e432011-03-27 04:05:00 +04001757 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs);
1758 }
Alan Coxe1eaea42010-03-26 11:32:54 +00001759 if (gsm->fcs != GOOD_FCS) {
1760 gsm->bad_fcs++;
1761 if (debug & 4)
Alan Cox5f9a31d2010-11-04 15:17:27 +00001762 pr_debug("BAD FCS %02x\n", gsm->fcs);
Alan Coxe1eaea42010-03-26 11:32:54 +00001763 return;
1764 }
1765 address = gsm->address >> 1;
1766 if (address >= NUM_DLCI)
1767 goto invalid;
1768
1769 cr = gsm->address & 1; /* C/R bit */
1770
1771 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
1772
1773 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */
1774 dlci = gsm->dlci[address];
1775
1776 switch (gsm->control) {
1777 case SABM|PF:
1778 if (cr == 0)
1779 goto invalid;
1780 if (dlci == NULL)
1781 dlci = gsm_dlci_alloc(gsm, address);
1782 if (dlci == NULL)
1783 return;
1784 if (dlci->dead)
1785 gsm_response(gsm, address, DM);
1786 else {
1787 gsm_response(gsm, address, UA);
1788 gsm_dlci_open(dlci);
1789 }
1790 break;
1791 case DISC|PF:
1792 if (cr == 0)
1793 goto invalid;
1794 if (dlci == NULL || dlci->state == DLCI_CLOSED) {
1795 gsm_response(gsm, address, DM);
1796 return;
1797 }
1798 /* Real close complete */
1799 gsm_response(gsm, address, UA);
1800 gsm_dlci_close(dlci);
1801 break;
1802 case UA:
1803 case UA|PF:
1804 if (cr == 0 || dlci == NULL)
1805 break;
1806 switch (dlci->state) {
1807 case DLCI_CLOSING:
1808 gsm_dlci_close(dlci);
1809 break;
1810 case DLCI_OPENING:
1811 gsm_dlci_open(dlci);
1812 break;
1813 }
1814 break;
1815 case DM: /* DM can be valid unsolicited */
1816 case DM|PF:
1817 if (cr)
1818 goto invalid;
1819 if (dlci == NULL)
1820 return;
1821 gsm_dlci_close(dlci);
1822 break;
1823 case UI:
1824 case UI|PF:
1825 case UIH:
1826 case UIH|PF:
1827#if 0
1828 if (cr)
1829 goto invalid;
1830#endif
1831 if (dlci == NULL || dlci->state != DLCI_OPEN) {
1832 gsm_command(gsm, address, DM|PF);
1833 return;
1834 }
1835 dlci->data(dlci, gsm->buf, gsm->len);
1836 break;
1837 default:
1838 goto invalid;
1839 }
1840 return;
1841invalid:
1842 gsm->malformed++;
1843 return;
1844}
1845
1846
1847/**
1848 * gsm0_receive - perform processing for non-transparency
1849 * @gsm: gsm data for this ldisc instance
1850 * @c: character
1851 *
1852 * Receive bytes in gsm mode 0
1853 */
1854
1855static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
1856{
Alan Coxc2f2f002010-11-04 15:17:03 +00001857 unsigned int len;
1858
Alan Coxe1eaea42010-03-26 11:32:54 +00001859 switch (gsm->state) {
1860 case GSM_SEARCH: /* SOF marker */
1861 if (c == GSM0_SOF) {
1862 gsm->state = GSM_ADDRESS;
1863 gsm->address = 0;
1864 gsm->len = 0;
1865 gsm->fcs = INIT_FCS;
1866 }
Alan Coxc2f2f002010-11-04 15:17:03 +00001867 break;
1868 case GSM_ADDRESS: /* Address EA */
Alan Coxe1eaea42010-03-26 11:32:54 +00001869 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1870 if (gsm_read_ea(&gsm->address, c))
1871 gsm->state = GSM_CONTROL;
1872 break;
1873 case GSM_CONTROL: /* Control Byte */
1874 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1875 gsm->control = c;
Alan Coxc2f2f002010-11-04 15:17:03 +00001876 gsm->state = GSM_LEN0;
Alan Coxe1eaea42010-03-26 11:32:54 +00001877 break;
Alan Coxc2f2f002010-11-04 15:17:03 +00001878 case GSM_LEN0: /* Length EA */
Alan Coxe1eaea42010-03-26 11:32:54 +00001879 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1880 if (gsm_read_ea(&gsm->len, c)) {
1881 if (gsm->len > gsm->mru) {
1882 gsm->bad_size++;
1883 gsm->state = GSM_SEARCH;
1884 break;
1885 }
1886 gsm->count = 0;
Alan Coxc2f2f002010-11-04 15:17:03 +00001887 if (!gsm->len)
1888 gsm->state = GSM_FCS;
1889 else
1890 gsm->state = GSM_DATA;
1891 break;
Alan Coxe1eaea42010-03-26 11:32:54 +00001892 }
Alan Coxc2f2f002010-11-04 15:17:03 +00001893 gsm->state = GSM_LEN1;
1894 break;
1895 case GSM_LEN1:
1896 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1897 len = c;
1898 gsm->len |= len << 7;
1899 if (gsm->len > gsm->mru) {
1900 gsm->bad_size++;
1901 gsm->state = GSM_SEARCH;
1902 break;
1903 }
1904 gsm->count = 0;
1905 if (!gsm->len)
1906 gsm->state = GSM_FCS;
1907 else
1908 gsm->state = GSM_DATA;
Alan Coxe1eaea42010-03-26 11:32:54 +00001909 break;
1910 case GSM_DATA: /* Data */
1911 gsm->buf[gsm->count++] = c;
1912 if (gsm->count == gsm->len)
1913 gsm->state = GSM_FCS;
1914 break;
1915 case GSM_FCS: /* FCS follows the packet */
Alan Coxc2f2f002010-11-04 15:17:03 +00001916 gsm->received_fcs = c;
Alan Coxe1eaea42010-03-26 11:32:54 +00001917 gsm_queue(gsm);
Alan Coxc2f2f002010-11-04 15:17:03 +00001918 gsm->state = GSM_SSOF;
1919 break;
1920 case GSM_SSOF:
1921 if (c == GSM0_SOF) {
1922 gsm->state = GSM_SEARCH;
1923 break;
1924 }
Alan Coxe1eaea42010-03-26 11:32:54 +00001925 break;
1926 }
1927}
1928
1929/**
Alan Coxc2f2f002010-11-04 15:17:03 +00001930 * gsm1_receive - perform processing for non-transparency
Alan Coxe1eaea42010-03-26 11:32:54 +00001931 * @gsm: gsm data for this ldisc instance
1932 * @c: character
1933 *
1934 * Receive bytes in mode 1 (Advanced option)
1935 */
1936
1937static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
1938{
1939 if (c == GSM1_SOF) {
1940 /* EOF is only valid in frame if we have got to the data state
1941 and received at least one byte (the FCS) */
1942 if (gsm->state == GSM_DATA && gsm->count) {
1943 /* Extract the FCS */
1944 gsm->count--;
1945 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
1946 gsm->len = gsm->count;
1947 gsm_queue(gsm);
1948 gsm->state = GSM_START;
1949 return;
1950 }
1951 /* Any partial frame was a runt so go back to start */
1952 if (gsm->state != GSM_START) {
1953 gsm->malformed++;
1954 gsm->state = GSM_START;
1955 }
1956 /* A SOF in GSM_START means we are still reading idling or
1957 framing bytes */
1958 return;
1959 }
1960
1961 if (c == GSM1_ESCAPE) {
1962 gsm->escape = 1;
1963 return;
1964 }
1965
1966 /* Only an unescaped SOF gets us out of GSM search */
1967 if (gsm->state == GSM_SEARCH)
1968 return;
1969
1970 if (gsm->escape) {
1971 c ^= GSM1_ESCAPE_BITS;
1972 gsm->escape = 0;
1973 }
1974 switch (gsm->state) {
1975 case GSM_START: /* First byte after SOF */
1976 gsm->address = 0;
1977 gsm->state = GSM_ADDRESS;
1978 gsm->fcs = INIT_FCS;
1979 /* Drop through */
1980 case GSM_ADDRESS: /* Address continuation */
1981 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1982 if (gsm_read_ea(&gsm->address, c))
1983 gsm->state = GSM_CONTROL;
1984 break;
1985 case GSM_CONTROL: /* Control Byte */
1986 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1987 gsm->control = c;
1988 gsm->count = 0;
1989 gsm->state = GSM_DATA;
1990 break;
1991 case GSM_DATA: /* Data */
Alan Cox5f9a31d2010-11-04 15:17:27 +00001992 if (gsm->count > gsm->mru) { /* Allow one for the FCS */
Alan Coxe1eaea42010-03-26 11:32:54 +00001993 gsm->state = GSM_OVERRUN;
1994 gsm->bad_size++;
1995 } else
1996 gsm->buf[gsm->count++] = c;
1997 break;
1998 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */
1999 break;
2000 }
2001}
2002
2003/**
2004 * gsm_error - handle tty error
2005 * @gsm: ldisc data
2006 * @data: byte received (may be invalid)
2007 * @flag: error received
2008 *
2009 * Handle an error in the receipt of data for a frame. Currently we just
2010 * go back to hunting for a SOF.
2011 *
2012 * FIXME: better diagnostics ?
2013 */
2014
2015static void gsm_error(struct gsm_mux *gsm,
2016 unsigned char data, unsigned char flag)
2017{
2018 gsm->state = GSM_SEARCH;
2019 gsm->io_error++;
2020}
2021
2022/**
2023 * gsm_cleanup_mux - generic GSM protocol cleanup
2024 * @gsm: our mux
2025 *
2026 * Clean up the bits of the mux which are the same for all framing
2027 * protocols. Remove the mux from the mux table, stop all the timers
2028 * and then shut down each device hanging up the channels as we go.
2029 */
2030
Rashika Kheria54af5832013-12-16 16:28:24 +05302031static void gsm_cleanup_mux(struct gsm_mux *gsm)
Alan Coxe1eaea42010-03-26 11:32:54 +00002032{
2033 int i;
2034 struct gsm_dlci *dlci = gsm->dlci[0];
Russ Gorby329e5672012-08-13 13:45:15 +01002035 struct gsm_msg *txq, *ntxq;
Alan Coxf17141f2011-08-26 11:28:11 +01002036 struct gsm_control *gc;
Alan Coxe1eaea42010-03-26 11:32:54 +00002037
2038 gsm->dead = 1;
2039
2040 spin_lock(&gsm_mux_lock);
2041 for (i = 0; i < MAX_MUX; i++) {
2042 if (gsm_mux[i] == gsm) {
2043 gsm_mux[i] = NULL;
2044 break;
2045 }
2046 }
2047 spin_unlock(&gsm_mux_lock);
2048 WARN_ON(i == MAX_MUX);
2049
Alan Coxf17141f2011-08-26 11:28:11 +01002050 /* In theory disconnecting DLCI 0 is sufficient but for some
2051 modems this is apparently not the case. */
2052 if (dlci) {
2053 gc = gsm_control_send(gsm, CMD_CLD, NULL, 0);
2054 if (gc)
2055 gsm_control_wait(gsm, gc);
2056 }
Alan Coxe1eaea42010-03-26 11:32:54 +00002057 del_timer_sync(&gsm->t2_timer);
2058 /* Now we are sure T2 has stopped */
2059 if (dlci) {
2060 dlci->dead = 1;
2061 gsm_dlci_begin_close(dlci);
2062 wait_event_interruptible(gsm->event,
2063 dlci->state == DLCI_CLOSED);
2064 }
2065 /* Free up any link layer users */
Chao Bidfabf7f2013-11-26 12:09:39 +08002066 mutex_lock(&gsm->mutex);
Alan Coxe1eaea42010-03-26 11:32:54 +00002067 for (i = 0; i < NUM_DLCI; i++)
2068 if (gsm->dlci[i])
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002069 gsm_dlci_release(gsm->dlci[i]);
Chao Bidfabf7f2013-11-26 12:09:39 +08002070 mutex_unlock(&gsm->mutex);
Alan Coxe1eaea42010-03-26 11:32:54 +00002071 /* Now wipe the queues */
Russ Gorbyb4338e12012-08-13 13:44:59 +01002072 list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list)
Alan Coxe1eaea42010-03-26 11:32:54 +00002073 kfree(txq);
Russ Gorbyb4338e12012-08-13 13:44:59 +01002074 INIT_LIST_HEAD(&gsm->tx_list);
Alan Coxe1eaea42010-03-26 11:32:54 +00002075}
Alan Coxe1eaea42010-03-26 11:32:54 +00002076
2077/**
2078 * gsm_activate_mux - generic GSM setup
2079 * @gsm: our mux
2080 *
2081 * Set up the bits of the mux which are the same for all framing
2082 * protocols. Add the mux to the mux table so it can be opened and
2083 * finally kick off connecting to DLCI 0 on the modem.
2084 */
2085
Rashika Kheria54af5832013-12-16 16:28:24 +05302086static int gsm_activate_mux(struct gsm_mux *gsm)
Alan Coxe1eaea42010-03-26 11:32:54 +00002087{
2088 struct gsm_dlci *dlci;
2089 int i = 0;
2090
Jiri Slabyc62fd1d2014-07-30 15:03:57 +02002091 setup_timer(&gsm->t2_timer, gsm_control_retransmit, (unsigned long)gsm);
Alan Coxe1eaea42010-03-26 11:32:54 +00002092 init_waitqueue_head(&gsm->event);
2093 spin_lock_init(&gsm->control_lock);
2094 spin_lock_init(&gsm->tx_lock);
2095
2096 if (gsm->encoding == 0)
2097 gsm->receive = gsm0_receive;
2098 else
2099 gsm->receive = gsm1_receive;
2100 gsm->error = gsm_error;
2101
2102 spin_lock(&gsm_mux_lock);
2103 for (i = 0; i < MAX_MUX; i++) {
2104 if (gsm_mux[i] == NULL) {
Russ Gorbyd50f6dc2011-06-14 13:35:32 -07002105 gsm->num = i;
Alan Coxe1eaea42010-03-26 11:32:54 +00002106 gsm_mux[i] = gsm;
2107 break;
2108 }
2109 }
2110 spin_unlock(&gsm_mux_lock);
2111 if (i == MAX_MUX)
2112 return -EBUSY;
2113
2114 dlci = gsm_dlci_alloc(gsm, 0);
2115 if (dlci == NULL)
2116 return -ENOMEM;
2117 gsm->dead = 0; /* Tty opens are now permissible */
2118 return 0;
2119}
Alan Coxe1eaea42010-03-26 11:32:54 +00002120
2121/**
2122 * gsm_free_mux - free up a mux
2123 * @mux: mux to free
2124 *
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002125 * Dispose of allocated resources for a dead mux
Alan Coxe1eaea42010-03-26 11:32:54 +00002126 */
Rashika Kheria54af5832013-12-16 16:28:24 +05302127static void gsm_free_mux(struct gsm_mux *gsm)
Alan Coxe1eaea42010-03-26 11:32:54 +00002128{
2129 kfree(gsm->txframe);
2130 kfree(gsm->buf);
2131 kfree(gsm);
2132}
Alan Coxe1eaea42010-03-26 11:32:54 +00002133
2134/**
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002135 * gsm_free_muxr - free up a mux
2136 * @mux: mux to free
2137 *
2138 * Dispose of allocated resources for a dead mux
2139 */
2140static void gsm_free_muxr(struct kref *ref)
2141{
2142 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref);
2143 gsm_free_mux(gsm);
2144}
2145
2146static inline void mux_get(struct gsm_mux *gsm)
2147{
2148 kref_get(&gsm->ref);
2149}
2150
2151static inline void mux_put(struct gsm_mux *gsm)
2152{
2153 kref_put(&gsm->ref, gsm_free_muxr);
2154}
2155
2156/**
Alan Coxe1eaea42010-03-26 11:32:54 +00002157 * gsm_alloc_mux - allocate a mux
2158 *
2159 * Creates a new mux ready for activation.
2160 */
2161
Rashika Kheria54af5832013-12-16 16:28:24 +05302162static struct gsm_mux *gsm_alloc_mux(void)
Alan Coxe1eaea42010-03-26 11:32:54 +00002163{
2164 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
2165 if (gsm == NULL)
2166 return NULL;
2167 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL);
2168 if (gsm->buf == NULL) {
2169 kfree(gsm);
2170 return NULL;
2171 }
2172 gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL);
2173 if (gsm->txframe == NULL) {
2174 kfree(gsm->buf);
2175 kfree(gsm);
2176 return NULL;
2177 }
2178 spin_lock_init(&gsm->lock);
Chao Bidfabf7f2013-11-26 12:09:39 +08002179 mutex_init(&gsm->mutex);
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002180 kref_init(&gsm->ref);
Russ Gorbyb4338e12012-08-13 13:44:59 +01002181 INIT_LIST_HEAD(&gsm->tx_list);
Alan Coxe1eaea42010-03-26 11:32:54 +00002182
2183 gsm->t1 = T1;
2184 gsm->t2 = T2;
2185 gsm->n2 = N2;
2186 gsm->ftype = UIH;
Alan Coxe1eaea42010-03-26 11:32:54 +00002187 gsm->adaption = 1;
2188 gsm->encoding = 1;
2189 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
2190 gsm->mtu = 64;
2191 gsm->dead = 1; /* Avoid early tty opens */
2192
2193 return gsm;
2194}
Alan Coxe1eaea42010-03-26 11:32:54 +00002195
Alan Coxe1eaea42010-03-26 11:32:54 +00002196/**
2197 * gsmld_output - write to link
2198 * @gsm: our mux
2199 * @data: bytes to output
2200 * @len: size
2201 *
2202 * Write a block of data from the GSM mux to the data channel. This
2203 * will eventually be serialized from above but at the moment isn't.
2204 */
2205
2206static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
2207{
2208 if (tty_write_room(gsm->tty) < len) {
2209 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
2210 return -ENOSPC;
2211 }
Joe Perches0a77c4f2011-04-25 16:46:49 -07002212 if (debug & 4)
2213 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET,
2214 data, len);
Alan Coxe1eaea42010-03-26 11:32:54 +00002215 gsm->tty->ops->write(gsm->tty, data, len);
2216 return len;
2217}
2218
2219/**
2220 * gsmld_attach_gsm - mode set up
2221 * @tty: our tty structure
2222 * @gsm: our mux
2223 *
2224 * Set up the MUX for basic mode and commence connecting to the
2225 * modem. Currently called from the line discipline set up but
2226 * will need moving to an ioctl path.
2227 */
2228
2229static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2230{
xinhui.pan850e93e2014-07-23 14:31:09 +08002231 int ret, i, base;
Alan Coxe1eaea42010-03-26 11:32:54 +00002232
2233 gsm->tty = tty_kref_get(tty);
2234 gsm->output = gsmld_output;
2235 ret = gsm_activate_mux(gsm);
2236 if (ret != 0)
2237 tty_kref_put(gsm->tty);
Russ Gorbyd50f6dc2011-06-14 13:35:32 -07002238 else {
2239 /* Don't register device 0 - this is the control channel and not
2240 a usable tty interface */
xinhui.pan850e93e2014-07-23 14:31:09 +08002241 base = gsm->num << 6; /* Base for this MUX */
Russ Gorbyd50f6dc2011-06-14 13:35:32 -07002242 for (i = 1; i < NUM_DLCI; i++)
2243 tty_register_device(gsm_tty_driver, base + i, NULL);
2244 }
Alan Coxe1eaea42010-03-26 11:32:54 +00002245 return ret;
2246}
2247
2248
2249/**
2250 * gsmld_detach_gsm - stop doing 0710 mux
Justin P. Mattock70f23fd2011-05-10 10:16:21 +02002251 * @tty: tty attached to the mux
Alan Coxe1eaea42010-03-26 11:32:54 +00002252 * @gsm: mux
2253 *
2254 * Shutdown and then clean up the resources used by the line discipline
2255 */
2256
2257static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2258{
Russ Gorbyd50f6dc2011-06-14 13:35:32 -07002259 int i;
2260 int base = gsm->num << 6; /* Base for this MUX */
2261
Alan Coxe1eaea42010-03-26 11:32:54 +00002262 WARN_ON(tty != gsm->tty);
Russ Gorbyd50f6dc2011-06-14 13:35:32 -07002263 for (i = 1; i < NUM_DLCI; i++)
2264 tty_unregister_device(gsm_tty_driver, base + i);
Alan Coxe1eaea42010-03-26 11:32:54 +00002265 gsm_cleanup_mux(gsm);
2266 tty_kref_put(gsm->tty);
2267 gsm->tty = NULL;
2268}
2269
Linus Torvalds55db4c62011-06-04 06:33:24 +09002270static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
2271 char *fp, int count)
Alan Coxe1eaea42010-03-26 11:32:54 +00002272{
2273 struct gsm_mux *gsm = tty->disc_data;
2274 const unsigned char *dp;
2275 char *f;
2276 int i;
2277 char buf[64];
Peter Hurley82f91fe2013-12-02 13:56:03 -05002278 char flags = TTY_NORMAL;
Alan Coxe1eaea42010-03-26 11:32:54 +00002279
Joe Perches0a77c4f2011-04-25 16:46:49 -07002280 if (debug & 4)
2281 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET,
2282 cp, count);
Alan Coxe1eaea42010-03-26 11:32:54 +00002283
2284 for (i = count, dp = cp, f = fp; i; i--, dp++) {
Peter Hurley82f91fe2013-12-02 13:56:03 -05002285 if (f)
2286 flags = *f++;
Alan Coxe1eaea42010-03-26 11:32:54 +00002287 switch (flags) {
2288 case TTY_NORMAL:
2289 gsm->receive(gsm, *dp);
2290 break;
2291 case TTY_OVERRUN:
2292 case TTY_BREAK:
2293 case TTY_PARITY:
2294 case TTY_FRAME:
2295 gsm->error(gsm, *dp, flags);
2296 break;
2297 default:
Frederic Beratc01af4f2012-08-13 13:43:58 +01002298 WARN_ONCE(1, "%s: unknown flag %d\n",
Alan Coxe1eaea42010-03-26 11:32:54 +00002299 tty_name(tty, buf), flags);
2300 break;
2301 }
2302 }
2303 /* FASYNC if needed ? */
2304 /* If clogged call tty_throttle(tty); */
2305}
2306
2307/**
2308 * gsmld_chars_in_buffer - report available bytes
2309 * @tty: tty device
2310 *
2311 * Report the number of characters buffered to be delivered to user
2312 * at this instant in time.
2313 *
2314 * Locking: gsm lock
2315 */
2316
2317static ssize_t gsmld_chars_in_buffer(struct tty_struct *tty)
2318{
2319 return 0;
2320}
2321
2322/**
2323 * gsmld_flush_buffer - clean input queue
2324 * @tty: terminal device
2325 *
2326 * Flush the input buffer. Called when the line discipline is
2327 * being closed, when the tty layer wants the buffer flushed (eg
2328 * at hangup).
2329 */
2330
2331static void gsmld_flush_buffer(struct tty_struct *tty)
2332{
2333}
2334
2335/**
2336 * gsmld_close - close the ldisc for this tty
2337 * @tty: device
2338 *
2339 * Called from the terminal layer when this line discipline is
2340 * being shut down, either because of a close or becsuse of a
2341 * discipline change. The function will not be called while other
2342 * ldisc methods are in progress.
2343 */
2344
2345static void gsmld_close(struct tty_struct *tty)
2346{
2347 struct gsm_mux *gsm = tty->disc_data;
2348
2349 gsmld_detach_gsm(tty, gsm);
2350
2351 gsmld_flush_buffer(tty);
2352 /* Do other clean up here */
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002353 mux_put(gsm);
Alan Coxe1eaea42010-03-26 11:32:54 +00002354}
2355
2356/**
2357 * gsmld_open - open an ldisc
2358 * @tty: terminal to open
2359 *
2360 * Called when this line discipline is being attached to the
2361 * terminal device. Can sleep. Called serialized so that no
2362 * other events will occur in parallel. No further open will occur
2363 * until a close.
2364 */
2365
2366static int gsmld_open(struct tty_struct *tty)
2367{
2368 struct gsm_mux *gsm;
xinhui.pan5a640962014-07-28 16:14:52 +08002369 int ret;
Alan Coxe1eaea42010-03-26 11:32:54 +00002370
2371 if (tty->ops->write == NULL)
2372 return -EINVAL;
2373
2374 /* Attach our ldisc data */
2375 gsm = gsm_alloc_mux();
2376 if (gsm == NULL)
2377 return -ENOMEM;
2378
2379 tty->disc_data = gsm;
2380 tty->receive_room = 65536;
2381
2382 /* Attach the initial passive connection */
2383 gsm->encoding = 1;
xinhui.pan5a640962014-07-28 16:14:52 +08002384
2385 ret = gsmld_attach_gsm(tty, gsm);
2386 if (ret != 0) {
2387 gsm_cleanup_mux(gsm);
2388 mux_put(gsm);
2389 }
2390 return ret;
Alan Coxe1eaea42010-03-26 11:32:54 +00002391}
2392
2393/**
2394 * gsmld_write_wakeup - asynchronous I/O notifier
2395 * @tty: tty device
2396 *
2397 * Required for the ptys, serial driver etc. since processes
2398 * that attach themselves to the master and rely on ASYNC
2399 * IO must be woken up
2400 */
2401
2402static void gsmld_write_wakeup(struct tty_struct *tty)
2403{
2404 struct gsm_mux *gsm = tty->disc_data;
Dan Carpenter328be392010-05-25 11:37:17 +02002405 unsigned long flags;
Alan Coxe1eaea42010-03-26 11:32:54 +00002406
2407 /* Queue poll */
2408 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
Russ Gorby5e447082012-08-13 13:44:40 +01002409 spin_lock_irqsave(&gsm->tx_lock, flags);
Alan Coxe1eaea42010-03-26 11:32:54 +00002410 gsm_data_kick(gsm);
Dan Carpenter328be392010-05-25 11:37:17 +02002411 if (gsm->tx_bytes < TX_THRESH_LO) {
Alan Coxe1eaea42010-03-26 11:32:54 +00002412 gsm_dlci_data_sweep(gsm);
Dan Carpenter328be392010-05-25 11:37:17 +02002413 }
Russ Gorby5e447082012-08-13 13:44:40 +01002414 spin_unlock_irqrestore(&gsm->tx_lock, flags);
Alan Coxe1eaea42010-03-26 11:32:54 +00002415}
2416
2417/**
2418 * gsmld_read - read function for tty
2419 * @tty: tty device
2420 * @file: file object
2421 * @buf: userspace buffer pointer
2422 * @nr: size of I/O
2423 *
2424 * Perform reads for the line discipline. We are guaranteed that the
2425 * line discipline will not be closed under us but we may get multiple
2426 * parallel readers and must handle this ourselves. We may also get
2427 * a hangup. Always called in user context, may sleep.
2428 *
2429 * This code must be sure never to sleep through a hangup.
2430 */
2431
2432static ssize_t gsmld_read(struct tty_struct *tty, struct file *file,
2433 unsigned char __user *buf, size_t nr)
2434{
2435 return -EOPNOTSUPP;
2436}
2437
2438/**
2439 * gsmld_write - write function for tty
2440 * @tty: tty device
2441 * @file: file object
2442 * @buf: userspace buffer pointer
2443 * @nr: size of I/O
2444 *
2445 * Called when the owner of the device wants to send a frame
2446 * itself (or some other control data). The data is transferred
2447 * as-is and must be properly framed and checksummed as appropriate
2448 * by userspace. Frames are either sent whole or not at all as this
2449 * avoids pain user side.
2450 */
2451
2452static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
2453 const unsigned char *buf, size_t nr)
2454{
2455 int space = tty_write_room(tty);
2456 if (space >= nr)
2457 return tty->ops->write(tty, buf, nr);
2458 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2459 return -ENOBUFS;
2460}
2461
2462/**
2463 * gsmld_poll - poll method for N_GSM0710
2464 * @tty: terminal device
2465 * @file: file accessing it
2466 * @wait: poll table
2467 *
2468 * Called when the line discipline is asked to poll() for data or
2469 * for special events. This code is not serialized with respect to
2470 * other events save open/close.
2471 *
2472 * This code must be sure never to sleep through a hangup.
2473 * Called without the kernel lock held - fine
2474 */
2475
2476static unsigned int gsmld_poll(struct tty_struct *tty, struct file *file,
2477 poll_table *wait)
2478{
2479 unsigned int mask = 0;
2480 struct gsm_mux *gsm = tty->disc_data;
2481
2482 poll_wait(file, &tty->read_wait, wait);
2483 poll_wait(file, &tty->write_wait, wait);
2484 if (tty_hung_up_p(file))
2485 mask |= POLLHUP;
2486 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
2487 mask |= POLLOUT | POLLWRNORM;
2488 if (gsm->dead)
2489 mask |= POLLHUP;
2490 return mask;
2491}
2492
2493static int gsmld_config(struct tty_struct *tty, struct gsm_mux *gsm,
2494 struct gsm_config *c)
2495{
2496 int need_close = 0;
2497 int need_restart = 0;
2498
2499 /* Stuff we don't support yet - UI or I frame transport, windowing */
Alan Cox5f9a31d2010-11-04 15:17:27 +00002500 if ((c->adaption != 1 && c->adaption != 2) || c->k)
Alan Coxe1eaea42010-03-26 11:32:54 +00002501 return -EOPNOTSUPP;
2502 /* Check the MRU/MTU range looks sane */
2503 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8)
2504 return -EINVAL;
2505 if (c->n2 < 3)
2506 return -EINVAL;
2507 if (c->encapsulation > 1) /* Basic, advanced, no I */
2508 return -EINVAL;
2509 if (c->initiator > 1)
2510 return -EINVAL;
2511 if (c->i == 0 || c->i > 2) /* UIH and UI only */
2512 return -EINVAL;
2513 /*
2514 * See what is needed for reconfiguration
2515 */
2516
2517 /* Timing fields */
2518 if (c->t1 != 0 && c->t1 != gsm->t1)
2519 need_restart = 1;
2520 if (c->t2 != 0 && c->t2 != gsm->t2)
2521 need_restart = 1;
2522 if (c->encapsulation != gsm->encoding)
2523 need_restart = 1;
2524 if (c->adaption != gsm->adaption)
2525 need_restart = 1;
2526 /* Requires care */
2527 if (c->initiator != gsm->initiator)
2528 need_close = 1;
2529 if (c->mru != gsm->mru)
2530 need_restart = 1;
2531 if (c->mtu != gsm->mtu)
2532 need_restart = 1;
2533
2534 /*
2535 * Close down what is needed, restart and initiate the new
2536 * configuration
2537 */
2538
2539 if (need_close || need_restart) {
2540 gsm_dlci_begin_close(gsm->dlci[0]);
2541 /* This will timeout if the link is down due to N2 expiring */
2542 wait_event_interruptible(gsm->event,
2543 gsm->dlci[0]->state == DLCI_CLOSED);
2544 if (signal_pending(current))
2545 return -EINTR;
2546 }
2547 if (need_restart)
2548 gsm_cleanup_mux(gsm);
2549
2550 gsm->initiator = c->initiator;
2551 gsm->mru = c->mru;
Ken Mills91f78f32011-01-25 14:17:45 +00002552 gsm->mtu = c->mtu;
Alan Coxe1eaea42010-03-26 11:32:54 +00002553 gsm->encoding = c->encapsulation;
2554 gsm->adaption = c->adaption;
Ken Mills820e62e2010-11-04 15:16:24 +00002555 gsm->n2 = c->n2;
Alan Coxe1eaea42010-03-26 11:32:54 +00002556
2557 if (c->i == 1)
2558 gsm->ftype = UIH;
2559 else if (c->i == 2)
2560 gsm->ftype = UI;
2561
2562 if (c->t1)
2563 gsm->t1 = c->t1;
2564 if (c->t2)
2565 gsm->t2 = c->t2;
2566
2567 /* FIXME: We need to separate activation/deactivation from adding
2568 and removing from the mux array */
2569 if (need_restart)
2570 gsm_activate_mux(gsm);
2571 if (gsm->initiator && need_close)
2572 gsm_dlci_begin_open(gsm->dlci[0]);
2573 return 0;
2574}
2575
2576static int gsmld_ioctl(struct tty_struct *tty, struct file *file,
2577 unsigned int cmd, unsigned long arg)
2578{
2579 struct gsm_config c;
2580 struct gsm_mux *gsm = tty->disc_data;
2581
2582 switch (cmd) {
2583 case GSMIOC_GETCONF:
2584 memset(&c, 0, sizeof(c));
2585 c.adaption = gsm->adaption;
2586 c.encapsulation = gsm->encoding;
2587 c.initiator = gsm->initiator;
2588 c.t1 = gsm->t1;
2589 c.t2 = gsm->t2;
2590 c.t3 = 0; /* Not supported */
2591 c.n2 = gsm->n2;
2592 if (gsm->ftype == UIH)
2593 c.i = 1;
2594 else
2595 c.i = 2;
Alan Cox5f9a31d2010-11-04 15:17:27 +00002596 pr_debug("Ftype %d i %d\n", gsm->ftype, c.i);
Alan Coxe1eaea42010-03-26 11:32:54 +00002597 c.mru = gsm->mru;
2598 c.mtu = gsm->mtu;
2599 c.k = 0;
2600 if (copy_to_user((void *)arg, &c, sizeof(c)))
2601 return -EFAULT;
2602 return 0;
2603 case GSMIOC_SETCONF:
2604 if (copy_from_user(&c, (void *)arg, sizeof(c)))
2605 return -EFAULT;
2606 return gsmld_config(tty, gsm, &c);
2607 default:
2608 return n_tty_ioctl_helper(tty, file, cmd, arg);
2609 }
2610}
2611
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002612/*
2613 * Network interface
2614 *
2615 */
2616
2617static int gsm_mux_net_open(struct net_device *net)
2618{
2619 pr_debug("%s called\n", __func__);
2620 netif_start_queue(net);
2621 return 0;
2622}
2623
2624static int gsm_mux_net_close(struct net_device *net)
2625{
2626 netif_stop_queue(net);
2627 return 0;
2628}
2629
2630static struct net_device_stats *gsm_mux_net_get_stats(struct net_device *net)
2631{
2632 return &((struct gsm_mux_net *)netdev_priv(net))->stats;
2633}
2634static void dlci_net_free(struct gsm_dlci *dlci)
2635{
2636 if (!dlci->net) {
2637 WARN_ON(1);
2638 return;
2639 }
2640 dlci->adaption = dlci->prev_adaption;
2641 dlci->data = dlci->prev_data;
2642 free_netdev(dlci->net);
2643 dlci->net = NULL;
2644}
2645static void net_free(struct kref *ref)
2646{
2647 struct gsm_mux_net *mux_net;
2648 struct gsm_dlci *dlci;
2649
2650 mux_net = container_of(ref, struct gsm_mux_net, ref);
2651 dlci = mux_net->dlci;
2652
2653 if (dlci->net) {
2654 unregister_netdev(dlci->net);
2655 dlci_net_free(dlci);
2656 }
2657}
2658
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002659static inline void muxnet_get(struct gsm_mux_net *mux_net)
2660{
2661 kref_get(&mux_net->ref);
2662}
2663
2664static inline void muxnet_put(struct gsm_mux_net *mux_net)
2665{
2666 kref_put(&mux_net->ref, net_free);
2667}
2668
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002669static int gsm_mux_net_start_xmit(struct sk_buff *skb,
2670 struct net_device *net)
2671{
2672 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
2673 struct gsm_dlci *dlci = mux_net->dlci;
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002674 muxnet_get(mux_net);
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002675
2676 skb_queue_head(&dlci->skb_list, skb);
2677 STATS(net).tx_packets++;
2678 STATS(net).tx_bytes += skb->len;
2679 gsm_dlci_data_kick(dlci);
2680 /* And tell the kernel when the last transmit started. */
2681 net->trans_start = jiffies;
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002682 muxnet_put(mux_net);
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002683 return NETDEV_TX_OK;
2684}
2685
2686/* called when a packet did not ack after watchdogtimeout */
2687static void gsm_mux_net_tx_timeout(struct net_device *net)
2688{
2689 /* Tell syslog we are hosed. */
2690 dev_dbg(&net->dev, "Tx timed out.\n");
2691
2692 /* Update statistics */
2693 STATS(net).tx_errors++;
2694}
2695
2696static void gsm_mux_rx_netchar(struct gsm_dlci *dlci,
2697 unsigned char *in_buf, int size)
2698{
2699 struct net_device *net = dlci->net;
2700 struct sk_buff *skb;
2701 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002702 muxnet_get(mux_net);
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002703
2704 /* Allocate an sk_buff */
2705 skb = dev_alloc_skb(size + NET_IP_ALIGN);
2706 if (!skb) {
2707 /* We got no receive buffer. */
2708 STATS(net).rx_dropped++;
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002709 muxnet_put(mux_net);
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002710 return;
2711 }
2712 skb_reserve(skb, NET_IP_ALIGN);
2713 memcpy(skb_put(skb, size), in_buf, size);
2714
2715 skb->dev = net;
2716 skb->protocol = __constant_htons(ETH_P_IP);
2717
2718 /* Ship it off to the kernel */
2719 netif_rx(skb);
2720
2721 /* update out statistics */
2722 STATS(net).rx_packets++;
2723 STATS(net).rx_bytes += size;
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002724 muxnet_put(mux_net);
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002725 return;
2726}
2727
Rashika Kheria54af5832013-12-16 16:28:24 +05302728static int gsm_change_mtu(struct net_device *net, int new_mtu)
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002729{
2730 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
2731 if ((new_mtu < 8) || (new_mtu > mux_net->dlci->gsm->mtu))
2732 return -EINVAL;
2733 net->mtu = new_mtu;
2734 return 0;
2735}
2736
2737static void gsm_mux_net_init(struct net_device *net)
2738{
2739 static const struct net_device_ops gsm_netdev_ops = {
2740 .ndo_open = gsm_mux_net_open,
2741 .ndo_stop = gsm_mux_net_close,
2742 .ndo_start_xmit = gsm_mux_net_start_xmit,
2743 .ndo_tx_timeout = gsm_mux_net_tx_timeout,
2744 .ndo_get_stats = gsm_mux_net_get_stats,
2745 .ndo_change_mtu = gsm_change_mtu,
2746 };
2747
2748 net->netdev_ops = &gsm_netdev_ops;
2749
2750 /* fill in the other fields */
2751 net->watchdog_timeo = GSM_NET_TX_TIMEOUT;
2752 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
2753 net->type = ARPHRD_NONE;
2754 net->tx_queue_len = 10;
2755}
2756
2757
2758/* caller holds the dlci mutex */
2759static void gsm_destroy_network(struct gsm_dlci *dlci)
2760{
2761 struct gsm_mux_net *mux_net;
2762
2763 pr_debug("destroy network interface");
2764 if (!dlci->net)
2765 return;
2766 mux_net = (struct gsm_mux_net *)netdev_priv(dlci->net);
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002767 muxnet_put(mux_net);
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002768}
2769
2770
2771/* caller holds the dlci mutex */
2772static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
2773{
2774 char *netname;
2775 int retval = 0;
2776 struct net_device *net;
2777 struct gsm_mux_net *mux_net;
2778
2779 if (!capable(CAP_NET_ADMIN))
2780 return -EPERM;
2781
2782 /* Already in a non tty mode */
2783 if (dlci->adaption > 2)
2784 return -EBUSY;
2785
2786 if (nc->protocol != htons(ETH_P_IP))
2787 return -EPROTONOSUPPORT;
2788
2789 if (nc->adaption != 3 && nc->adaption != 4)
2790 return -EPROTONOSUPPORT;
2791
2792 pr_debug("create network interface");
2793
2794 netname = "gsm%d";
2795 if (nc->if_name[0] != '\0')
2796 netname = nc->if_name;
Tom Gundersenc835a672014-07-14 16:37:24 +02002797 net = alloc_netdev(sizeof(struct gsm_mux_net), netname,
2798 NET_NAME_UNKNOWN, gsm_mux_net_init);
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002799 if (!net) {
2800 pr_err("alloc_netdev failed");
2801 return -ENOMEM;
2802 }
2803 net->mtu = dlci->gsm->mtu;
2804 mux_net = (struct gsm_mux_net *)netdev_priv(net);
2805 mux_net->dlci = dlci;
2806 kref_init(&mux_net->ref);
2807 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */
2808
2809 /* reconfigure dlci for network */
2810 dlci->prev_adaption = dlci->adaption;
2811 dlci->prev_data = dlci->data;
2812 dlci->adaption = nc->adaption;
2813 dlci->data = gsm_mux_rx_netchar;
2814 dlci->net = net;
2815
2816 pr_debug("register netdev");
2817 retval = register_netdev(net);
2818 if (retval) {
2819 pr_err("network register fail %d\n", retval);
2820 dlci_net_free(dlci);
2821 return retval;
2822 }
2823 return net->ifindex; /* return network index */
2824}
Alan Coxe1eaea42010-03-26 11:32:54 +00002825
2826/* Line discipline for real tty */
2827struct tty_ldisc_ops tty_ldisc_packet = {
2828 .owner = THIS_MODULE,
2829 .magic = TTY_LDISC_MAGIC,
2830 .name = "n_gsm",
2831 .open = gsmld_open,
2832 .close = gsmld_close,
2833 .flush_buffer = gsmld_flush_buffer,
2834 .chars_in_buffer = gsmld_chars_in_buffer,
2835 .read = gsmld_read,
2836 .write = gsmld_write,
2837 .ioctl = gsmld_ioctl,
2838 .poll = gsmld_poll,
2839 .receive_buf = gsmld_receive_buf,
2840 .write_wakeup = gsmld_write_wakeup
2841};
2842
2843/*
2844 * Virtual tty side
2845 */
2846
2847#define TX_SIZE 512
2848
2849static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk)
2850{
2851 u8 modembits[5];
2852 struct gsm_control *ctrl;
2853 int len = 2;
2854
2855 if (brk)
2856 len++;
2857
2858 modembits[0] = len << 1 | EA; /* Data bytes */
2859 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */
2860 modembits[2] = gsm_encode_modem(dlci) << 1 | EA;
2861 if (brk)
2862 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */
2863 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1);
2864 if (ctrl == NULL)
2865 return -ENOMEM;
2866 return gsm_control_wait(dlci->gsm, ctrl);
2867}
2868
2869static int gsm_carrier_raised(struct tty_port *port)
2870{
2871 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2872 /* Not yet open so no carrier info */
2873 if (dlci->state != DLCI_OPEN)
2874 return 0;
2875 if (debug & 2)
2876 return 1;
2877 return dlci->modem_rx & TIOCM_CD;
2878}
2879
2880static void gsm_dtr_rts(struct tty_port *port, int onoff)
2881{
2882 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2883 unsigned int modem_tx = dlci->modem_tx;
2884 if (onoff)
2885 modem_tx |= TIOCM_DTR | TIOCM_RTS;
2886 else
2887 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
2888 if (modem_tx != dlci->modem_tx) {
2889 dlci->modem_tx = modem_tx;
2890 gsmtty_modem_update(dlci, 0);
2891 }
2892}
2893
2894static const struct tty_port_operations gsm_port_ops = {
2895 .carrier_raised = gsm_carrier_raised,
2896 .dtr_rts = gsm_dtr_rts,
Jiri Slaby9a8e62b2012-11-15 09:49:53 +01002897 .destruct = gsm_dlci_free,
Alan Coxe1eaea42010-03-26 11:32:54 +00002898};
2899
Jiri Slaby86176ed2012-08-07 21:47:28 +02002900static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty)
Alan Coxe1eaea42010-03-26 11:32:54 +00002901{
2902 struct gsm_mux *gsm;
2903 struct gsm_dlci *dlci;
Alan Coxe1eaea42010-03-26 11:32:54 +00002904 unsigned int line = tty->index;
2905 unsigned int mux = line >> 6;
Jiri Slaby86176ed2012-08-07 21:47:28 +02002906 bool alloc = false;
2907 int ret;
Alan Coxe1eaea42010-03-26 11:32:54 +00002908
2909 line = line & 0x3F;
2910
2911 if (mux >= MAX_MUX)
2912 return -ENXIO;
2913 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
2914 if (gsm_mux[mux] == NULL)
2915 return -EUNATCH;
2916 if (line == 0 || line > 61) /* 62/63 reserved */
2917 return -ECHRNG;
2918 gsm = gsm_mux[mux];
2919 if (gsm->dead)
2920 return -EL2HLT;
Aldo Iljazif3c909b2013-07-08 22:28:00 +03002921 /* If DLCI 0 is not yet fully open return an error.
2922 This is ok from a locking
2923 perspective as we don't have to worry about this
2924 if DLCI0 is lost */
Chao Bidfabf7f2013-11-26 12:09:39 +08002925 mutex_lock(&gsm->mutex);
2926 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN) {
2927 mutex_unlock(&gsm->mutex);
xiaojin7e8ac7b2012-08-13 13:43:15 +01002928 return -EL2NSYNC;
Chao Bidfabf7f2013-11-26 12:09:39 +08002929 }
Alan Coxe1eaea42010-03-26 11:32:54 +00002930 dlci = gsm->dlci[line];
Jiri Slaby86176ed2012-08-07 21:47:28 +02002931 if (dlci == NULL) {
2932 alloc = true;
Alan Coxe1eaea42010-03-26 11:32:54 +00002933 dlci = gsm_dlci_alloc(gsm, line);
Jiri Slaby86176ed2012-08-07 21:47:28 +02002934 }
Chao Bidfabf7f2013-11-26 12:09:39 +08002935 if (dlci == NULL) {
2936 mutex_unlock(&gsm->mutex);
Alan Coxe1eaea42010-03-26 11:32:54 +00002937 return -ENOMEM;
Chao Bidfabf7f2013-11-26 12:09:39 +08002938 }
Jiri Slaby86176ed2012-08-07 21:47:28 +02002939 ret = tty_port_install(&dlci->port, driver, tty);
2940 if (ret) {
2941 if (alloc)
2942 dlci_put(dlci);
Chao Bidfabf7f2013-11-26 12:09:39 +08002943 mutex_unlock(&gsm->mutex);
Jiri Slaby86176ed2012-08-07 21:47:28 +02002944 return ret;
2945 }
2946
Chao Bidfabf7f2013-11-26 12:09:39 +08002947 dlci_get(dlci);
2948 dlci_get(gsm->dlci[0]);
2949 mux_get(gsm);
Alan Coxe1eaea42010-03-26 11:32:54 +00002950 tty->driver_data = dlci;
Chao Bidfabf7f2013-11-26 12:09:39 +08002951 mutex_unlock(&gsm->mutex);
Jiri Slaby86176ed2012-08-07 21:47:28 +02002952
2953 return 0;
2954}
2955
2956static int gsmtty_open(struct tty_struct *tty, struct file *filp)
2957{
2958 struct gsm_dlci *dlci = tty->driver_data;
2959 struct tty_port *port = &dlci->port;
2960
2961 port->count++;
Alan Coxe1eaea42010-03-26 11:32:54 +00002962 tty_port_tty_set(port, tty);
2963
2964 dlci->modem_rx = 0;
2965 /* We could in theory open and close before we wait - eg if we get
2966 a DM straight back. This is ok as that will have caused a hangup */
2967 set_bit(ASYNCB_INITIALIZED, &port->flags);
2968 /* Start sending off SABM messages */
2969 gsm_dlci_begin_open(dlci);
2970 /* And wait for virtual carrier */
2971 return tty_port_block_til_ready(port, tty, filp);
2972}
2973
2974static void gsmtty_close(struct tty_struct *tty, struct file *filp)
2975{
2976 struct gsm_dlci *dlci = tty->driver_data;
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002977 struct gsm_mux *gsm;
2978
Alan Coxe1eaea42010-03-26 11:32:54 +00002979 if (dlci == NULL)
2980 return;
Dirkjan Bussink4d9b1092013-01-30 11:44:50 +01002981 if (dlci->state == DLCI_CLOSED)
2982 return;
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002983 mutex_lock(&dlci->mutex);
2984 gsm_destroy_network(dlci);
2985 mutex_unlock(&dlci->mutex);
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002986 gsm = dlci->gsm;
Alan Coxe1eaea42010-03-26 11:32:54 +00002987 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
Chao Bidfabf7f2013-11-26 12:09:39 +08002988 return;
Alan Coxe1eaea42010-03-26 11:32:54 +00002989 gsm_dlci_begin_close(dlci);
Johan Hovold957daca2013-03-07 15:55:51 +01002990 if (test_bit(ASYNCB_INITIALIZED, &dlci->port.flags)) {
2991 if (C_HUPCL(tty))
2992 tty_port_lower_dtr_rts(&dlci->port);
2993 }
Alan Coxe1eaea42010-03-26 11:32:54 +00002994 tty_port_close_end(&dlci->port, tty);
2995 tty_port_tty_set(&dlci->port, NULL);
Chao Bidfabf7f2013-11-26 12:09:39 +08002996 return;
Alan Coxe1eaea42010-03-26 11:32:54 +00002997}
2998
2999static void gsmtty_hangup(struct tty_struct *tty)
3000{
3001 struct gsm_dlci *dlci = tty->driver_data;
Dirkjan Bussink4d9b1092013-01-30 11:44:50 +01003002 if (dlci->state == DLCI_CLOSED)
3003 return;
Alan Coxe1eaea42010-03-26 11:32:54 +00003004 tty_port_hangup(&dlci->port);
3005 gsm_dlci_begin_close(dlci);
3006}
3007
3008static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf,
3009 int len)
3010{
Dirkjan Bussink4d9b1092013-01-30 11:44:50 +01003011 int sent;
Alan Coxe1eaea42010-03-26 11:32:54 +00003012 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 /* Stuff the bytes into the fifo queue */
Dirkjan Bussink4d9b1092013-01-30 11:44:50 +01003016 sent = kfifo_in_locked(dlci->fifo, buf, len, &dlci->lock);
Alan Coxe1eaea42010-03-26 11:32:54 +00003017 /* Need to kick the channel */
3018 gsm_dlci_data_kick(dlci);
3019 return sent;
3020}
3021
3022static int gsmtty_write_room(struct tty_struct *tty)
3023{
3024 struct gsm_dlci *dlci = tty->driver_data;
Dirkjan Bussink4d9b1092013-01-30 11:44:50 +01003025 if (dlci->state == DLCI_CLOSED)
3026 return -EINVAL;
Alan Coxe1eaea42010-03-26 11:32:54 +00003027 return TX_SIZE - kfifo_len(dlci->fifo);
3028}
3029
3030static int gsmtty_chars_in_buffer(struct tty_struct *tty)
3031{
3032 struct gsm_dlci *dlci = tty->driver_data;
Dirkjan Bussink4d9b1092013-01-30 11:44:50 +01003033 if (dlci->state == DLCI_CLOSED)
3034 return -EINVAL;
Alan Coxe1eaea42010-03-26 11:32:54 +00003035 return kfifo_len(dlci->fifo);
3036}
3037
3038static void gsmtty_flush_buffer(struct tty_struct *tty)
3039{
3040 struct gsm_dlci *dlci = tty->driver_data;
Dirkjan Bussink4d9b1092013-01-30 11:44:50 +01003041 if (dlci->state == DLCI_CLOSED)
3042 return;
Alan Coxe1eaea42010-03-26 11:32:54 +00003043 /* Caution needed: If we implement reliable transport classes
3044 then the data being transmitted can't simply be junked once
3045 it has first hit the stack. Until then we can just blow it
3046 away */
3047 kfifo_reset(dlci->fifo);
3048 /* Need to unhook this DLCI from the transmit queue logic */
3049}
3050
3051static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
3052{
3053 /* The FIFO handles the queue so the kernel will do the right
3054 thing waiting on chars_in_buffer before calling us. No work
3055 to do here */
3056}
3057
Alan Cox60b33c12011-02-14 16:26:14 +00003058static int gsmtty_tiocmget(struct tty_struct *tty)
Alan Coxe1eaea42010-03-26 11:32:54 +00003059{
3060 struct gsm_dlci *dlci = tty->driver_data;
Dirkjan Bussink4d9b1092013-01-30 11:44:50 +01003061 if (dlci->state == DLCI_CLOSED)
3062 return -EINVAL;
Alan Coxe1eaea42010-03-26 11:32:54 +00003063 return dlci->modem_rx;
3064}
3065
Alan Cox20b9d172011-02-14 16:26:50 +00003066static int gsmtty_tiocmset(struct tty_struct *tty,
Alan Coxe1eaea42010-03-26 11:32:54 +00003067 unsigned int set, unsigned int clear)
3068{
3069 struct gsm_dlci *dlci = tty->driver_data;
3070 unsigned int modem_tx = dlci->modem_tx;
3071
Dirkjan Bussink4d9b1092013-01-30 11:44:50 +01003072 if (dlci->state == DLCI_CLOSED)
3073 return -EINVAL;
Nikola Diklic-Perincf168072011-09-23 10:59:43 +02003074 modem_tx &= ~clear;
Alan Coxe1eaea42010-03-26 11:32:54 +00003075 modem_tx |= set;
3076
3077 if (modem_tx != dlci->modem_tx) {
3078 dlci->modem_tx = modem_tx;
3079 return gsmtty_modem_update(dlci, 0);
3080 }
3081 return 0;
3082}
3083
3084
Alan Cox6caa76b2011-02-14 16:27:22 +00003085static int gsmtty_ioctl(struct tty_struct *tty,
Alan Coxe1eaea42010-03-26 11:32:54 +00003086 unsigned int cmd, unsigned long arg)
3087{
Russ Gorbybcd5abe2011-06-16 14:20:12 -07003088 struct gsm_dlci *dlci = tty->driver_data;
3089 struct gsm_netconfig nc;
3090 int index;
3091
Dirkjan Bussink4d9b1092013-01-30 11:44:50 +01003092 if (dlci->state == DLCI_CLOSED)
3093 return -EINVAL;
Russ Gorbybcd5abe2011-06-16 14:20:12 -07003094 switch (cmd) {
3095 case GSMIOC_ENABLE_NET:
3096 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc)))
3097 return -EFAULT;
3098 nc.if_name[IFNAMSIZ-1] = '\0';
3099 /* return net interface index or error code */
3100 mutex_lock(&dlci->mutex);
3101 index = gsm_create_network(dlci, &nc);
3102 mutex_unlock(&dlci->mutex);
3103 if (copy_to_user((void __user *)arg, &nc, sizeof(nc)))
3104 return -EFAULT;
3105 return index;
3106 case GSMIOC_DISABLE_NET:
3107 if (!capable(CAP_NET_ADMIN))
3108 return -EPERM;
3109 mutex_lock(&dlci->mutex);
3110 gsm_destroy_network(dlci);
3111 mutex_unlock(&dlci->mutex);
3112 return 0;
3113 default:
3114 return -ENOIOCTLCMD;
3115 }
Alan Coxe1eaea42010-03-26 11:32:54 +00003116}
3117
3118static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old)
3119{
Dirkjan Bussink4d9b1092013-01-30 11:44:50 +01003120 struct gsm_dlci *dlci = tty->driver_data;
3121 if (dlci->state == DLCI_CLOSED)
3122 return;
Alan Coxe1eaea42010-03-26 11:32:54 +00003123 /* For the moment its fixed. In actual fact the speed information
3124 for the virtual channel can be propogated in both directions by
3125 the RPN control message. This however rapidly gets nasty as we
3126 then have to remap modem signals each way according to whether
3127 our virtual cable is null modem etc .. */
Alan Coxadc8d742012-07-14 15:31:47 +01003128 tty_termios_copy_hw(&tty->termios, old);
Alan Coxe1eaea42010-03-26 11:32:54 +00003129}
3130
3131static void gsmtty_throttle(struct tty_struct *tty)
3132{
3133 struct gsm_dlci *dlci = tty->driver_data;
Dirkjan Bussink4d9b1092013-01-30 11:44:50 +01003134 if (dlci->state == DLCI_CLOSED)
3135 return;
Alan Coxadc8d742012-07-14 15:31:47 +01003136 if (tty->termios.c_cflag & CRTSCTS)
Alan Coxe1eaea42010-03-26 11:32:54 +00003137 dlci->modem_tx &= ~TIOCM_DTR;
3138 dlci->throttled = 1;
3139 /* Send an MSC with DTR cleared */
3140 gsmtty_modem_update(dlci, 0);
3141}
3142
3143static void gsmtty_unthrottle(struct tty_struct *tty)
3144{
3145 struct gsm_dlci *dlci = tty->driver_data;
Dirkjan Bussink4d9b1092013-01-30 11:44:50 +01003146 if (dlci->state == DLCI_CLOSED)
3147 return;
Alan Coxadc8d742012-07-14 15:31:47 +01003148 if (tty->termios.c_cflag & CRTSCTS)
Alan Coxe1eaea42010-03-26 11:32:54 +00003149 dlci->modem_tx |= TIOCM_DTR;
3150 dlci->throttled = 0;
3151 /* Send an MSC with DTR set */
3152 gsmtty_modem_update(dlci, 0);
3153}
3154
3155static int gsmtty_break_ctl(struct tty_struct *tty, int state)
3156{
3157 struct gsm_dlci *dlci = tty->driver_data;
3158 int encode = 0; /* Off */
Dirkjan Bussink4d9b1092013-01-30 11:44:50 +01003159 if (dlci->state == DLCI_CLOSED)
3160 return -EINVAL;
Alan Coxe1eaea42010-03-26 11:32:54 +00003161
3162 if (state == -1) /* "On indefinitely" - we can't encode this
3163 properly */
3164 encode = 0x0F;
3165 else if (state > 0) {
3166 encode = state / 200; /* mS to encoding */
3167 if (encode > 0x0F)
3168 encode = 0x0F; /* Best effort */
3169 }
3170 return gsmtty_modem_update(dlci, encode);
3171}
3172
Chao Bidfabf7f2013-11-26 12:09:39 +08003173static void gsmtty_remove(struct tty_driver *driver, struct tty_struct *tty)
3174{
3175 struct gsm_dlci *dlci = tty->driver_data;
3176 struct gsm_mux *gsm = dlci->gsm;
3177
3178 dlci_put(dlci);
3179 dlci_put(gsm->dlci[0]);
3180 mux_put(gsm);
3181 driver->ttys[tty->index] = NULL;
3182}
Alan Coxe1eaea42010-03-26 11:32:54 +00003183
3184/* Virtual ttys for the demux */
3185static const struct tty_operations gsmtty_ops = {
Jiri Slaby86176ed2012-08-07 21:47:28 +02003186 .install = gsmtty_install,
Alan Coxe1eaea42010-03-26 11:32:54 +00003187 .open = gsmtty_open,
3188 .close = gsmtty_close,
3189 .write = gsmtty_write,
3190 .write_room = gsmtty_write_room,
3191 .chars_in_buffer = gsmtty_chars_in_buffer,
3192 .flush_buffer = gsmtty_flush_buffer,
3193 .ioctl = gsmtty_ioctl,
3194 .throttle = gsmtty_throttle,
3195 .unthrottle = gsmtty_unthrottle,
3196 .set_termios = gsmtty_set_termios,
3197 .hangup = gsmtty_hangup,
3198 .wait_until_sent = gsmtty_wait_until_sent,
3199 .tiocmget = gsmtty_tiocmget,
3200 .tiocmset = gsmtty_tiocmset,
3201 .break_ctl = gsmtty_break_ctl,
Chao Bidfabf7f2013-11-26 12:09:39 +08003202 .remove = gsmtty_remove,
Alan Coxe1eaea42010-03-26 11:32:54 +00003203};
3204
3205
3206
3207static int __init gsm_init(void)
3208{
3209 /* Fill in our line protocol discipline, and register it */
3210 int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet);
3211 if (status != 0) {
Alan Cox5f9a31d2010-11-04 15:17:27 +00003212 pr_err("n_gsm: can't register line discipline (err = %d)\n",
3213 status);
Alan Coxe1eaea42010-03-26 11:32:54 +00003214 return status;
3215 }
3216
3217 gsm_tty_driver = alloc_tty_driver(256);
3218 if (!gsm_tty_driver) {
3219 tty_unregister_ldisc(N_GSM0710);
Alan Cox5f9a31d2010-11-04 15:17:27 +00003220 pr_err("gsm_init: tty allocation failed.\n");
Alan Coxe1eaea42010-03-26 11:32:54 +00003221 return -EINVAL;
3222 }
Alan Coxe1eaea42010-03-26 11:32:54 +00003223 gsm_tty_driver->driver_name = "gsmtty";
3224 gsm_tty_driver->name = "gsmtty";
3225 gsm_tty_driver->major = 0; /* Dynamic */
3226 gsm_tty_driver->minor_start = 0;
3227 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
3228 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
3229 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV
Alan Cox5f9a31d2010-11-04 15:17:27 +00003230 | TTY_DRIVER_HARDWARE_BREAK;
Alan Coxe1eaea42010-03-26 11:32:54 +00003231 gsm_tty_driver->init_termios = tty_std_termios;
3232 /* Fixme */
3233 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
3234 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
3235
3236 spin_lock_init(&gsm_mux_lock);
3237
3238 if (tty_register_driver(gsm_tty_driver)) {
3239 put_tty_driver(gsm_tty_driver);
3240 tty_unregister_ldisc(N_GSM0710);
Alan Cox5f9a31d2010-11-04 15:17:27 +00003241 pr_err("gsm_init: tty registration failed.\n");
Alan Coxe1eaea42010-03-26 11:32:54 +00003242 return -EBUSY;
3243 }
Alan Cox5f9a31d2010-11-04 15:17:27 +00003244 pr_debug("gsm_init: loaded as %d,%d.\n",
3245 gsm_tty_driver->major, gsm_tty_driver->minor_start);
Alan Coxe1eaea42010-03-26 11:32:54 +00003246 return 0;
3247}
3248
3249static void __exit gsm_exit(void)
3250{
3251 int status = tty_unregister_ldisc(N_GSM0710);
3252 if (status != 0)
Alan Cox5f9a31d2010-11-04 15:17:27 +00003253 pr_err("n_gsm: can't unregister line discipline (err = %d)\n",
3254 status);
Alan Coxe1eaea42010-03-26 11:32:54 +00003255 tty_unregister_driver(gsm_tty_driver);
3256 put_tty_driver(gsm_tty_driver);
Alan Coxe1eaea42010-03-26 11:32:54 +00003257}
3258
3259module_init(gsm_init);
3260module_exit(gsm_exit);
3261
3262
3263MODULE_LICENSE("GPL");
3264MODULE_ALIAS_LDISC(N_GSM0710);