blob: 1e8e8ce55959e4aef1d82ce38a622fbb581f8caf [file] [log] [blame]
Alan Coxe1eaea42010-03-26 11:32:54 +00001/*
2 * n_gsm.c GSM 0710 tty multiplexor
3 * Copyright (c) 2009/10 Intel Corporation
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
17 *
18 * * THIS IS A DEVELOPMENT SNAPSHOT IT IS NOT A FINAL RELEASE *
19 *
20 * TO DO:
21 * Mostly done: ioctls for setting modes/timing
Alan Cox5f9a31d2010-11-04 15:17:27 +000022 * Partly done: hooks so you can pull off frames to non tty devs
Alan Coxe1eaea42010-03-26 11:32:54 +000023 * Restart DLCI 0 when it closes ?
Alan Coxe1eaea42010-03-26 11:32:54 +000024 * Improve the tx engine
25 * Resolve tx side locking by adding a queue_head and routing
26 * all control traffic via it
27 * General tidy/document
28 * Review the locking/move to refcounts more (mux now moved to an
29 * alloc/free model ready)
30 * Use newest tty open/close port helpers and install hooks
31 * What to do about power functions ?
32 * Termios setting and negotiation
33 * Do we need a 'which mux are you' ioctl to correlate mux and tty sets
34 *
35 */
36
37#include <linux/types.h>
38#include <linux/major.h>
39#include <linux/errno.h>
40#include <linux/signal.h>
41#include <linux/fcntl.h>
42#include <linux/sched.h>
43#include <linux/interrupt.h>
44#include <linux/tty.h>
Alan Coxe1eaea42010-03-26 11:32:54 +000045#include <linux/ctype.h>
46#include <linux/mm.h>
47#include <linux/string.h>
48#include <linux/slab.h>
49#include <linux/poll.h>
50#include <linux/bitops.h>
51#include <linux/file.h>
52#include <linux/uaccess.h>
53#include <linux/module.h>
54#include <linux/timer.h>
55#include <linux/tty_flip.h>
56#include <linux/tty_driver.h>
57#include <linux/serial.h>
58#include <linux/kfifo.h>
59#include <linux/skbuff.h>
Russ Gorbybcd5abe2011-06-16 14:20:12 -070060#include <net/arp.h>
61#include <linux/ip.h>
62#include <linux/netdevice.h>
63#include <linux/etherdevice.h>
Alan Coxe1eaea42010-03-26 11:32:54 +000064#include <linux/gsmmux.h>
65
66static int debug;
67module_param(debug, int, 0600);
68
Alan Coxa8d12002011-11-08 18:02:10 +000069/* Defaults: these are from the specification */
70
71#define T1 10 /* 100mS */
72#define T2 34 /* 333mS */
73#define N2 3 /* Retry 3 times */
Alan Coxe1eaea42010-03-26 11:32:54 +000074
75/* Use long timers for testing at low speed with debug on */
76#ifdef DEBUG_TIMING
Alan Coxa8d12002011-11-08 18:02:10 +000077#define T1 100
78#define T2 200
Alan Coxe1eaea42010-03-26 11:32:54 +000079#endif
80
Alan Cox5f9a31d2010-11-04 15:17:27 +000081/*
Lucas De Marchi25985ed2011-03-30 22:57:33 -030082 * Semi-arbitrary buffer size limits. 0710 is normally run with 32-64 byte
Alan Cox5f9a31d2010-11-04 15:17:27 +000083 * limits so this is plenty
84 */
Russ Gorbybcd5abe2011-06-16 14:20:12 -070085#define MAX_MRU 1500
86#define MAX_MTU 1500
87#define GSM_NET_TX_TIMEOUT (HZ*10)
88
89/**
90 * struct gsm_mux_net - network interface
91 * @struct gsm_dlci* dlci
92 * @struct net_device_stats stats;
93 *
94 * Created when net interface is initialized.
95 **/
96struct gsm_mux_net {
97 struct kref ref;
98 struct gsm_dlci *dlci;
99 struct net_device_stats stats;
100};
101
102#define STATS(net) (((struct gsm_mux_net *)netdev_priv(net))->stats)
Alan Coxe1eaea42010-03-26 11:32:54 +0000103
104/*
105 * Each block of data we have queued to go out is in the form of
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300106 * a gsm_msg which holds everything we need in a link layer independent
Alan Coxe1eaea42010-03-26 11:32:54 +0000107 * format
108 */
109
110struct gsm_msg {
Russ Gorbyb4338e12012-08-13 13:44:59 +0100111 struct list_head list;
Alan Coxe1eaea42010-03-26 11:32:54 +0000112 u8 addr; /* DLCI address + flags */
113 u8 ctrl; /* Control byte + flags */
114 unsigned int len; /* Length of data block (can be zero) */
115 unsigned char *data; /* Points into buffer but not at the start */
116 unsigned char buffer[0];
117};
118
119/*
120 * Each active data link has a gsm_dlci structure associated which ties
121 * the link layer to an optional tty (if the tty side is open). To avoid
122 * complexity right now these are only ever freed up when the mux is
123 * shut down.
124 *
125 * At the moment we don't free DLCI objects until the mux is torn down
126 * this avoid object life time issues but might be worth review later.
127 */
128
129struct gsm_dlci {
130 struct gsm_mux *gsm;
131 int addr;
132 int state;
133#define DLCI_CLOSED 0
134#define DLCI_OPENING 1 /* Sending SABM not seen UA */
135#define DLCI_OPEN 2 /* SABM/UA complete */
136#define DLCI_CLOSING 3 /* Sending DISC not seen UA/DM */
Russ Gorby6ab8fba2011-06-16 14:20:13 -0700137 struct kref ref; /* freed from port or mux close */
Russ Gorbybcd5abe2011-06-16 14:20:12 -0700138 struct mutex mutex;
Alan Coxe1eaea42010-03-26 11:32:54 +0000139
140 /* Link layer */
141 spinlock_t lock; /* Protects the internal state */
142 struct timer_list t1; /* Retransmit timer for SABM and UA */
143 int retries;
144 /* Uplink tty if active */
145 struct tty_port port; /* The tty bound to this DLCI if there is one */
146 struct kfifo *fifo; /* Queue fifo for the DLCI */
147 struct kfifo _fifo; /* For new fifo API porting only */
148 int adaption; /* Adaption layer in use */
Russ Gorbybcd5abe2011-06-16 14:20:12 -0700149 int prev_adaption;
Alan Coxe1eaea42010-03-26 11:32:54 +0000150 u32 modem_rx; /* Our incoming virtual modem lines */
151 u32 modem_tx; /* Our outgoing modem lines */
152 int dead; /* Refuse re-open */
153 /* Flow control */
154 int throttled; /* Private copy of throttle state */
155 int constipated; /* Throttle status for outgoing */
156 /* Packetised I/O */
157 struct sk_buff *skb; /* Frame being sent */
158 struct sk_buff_head skb_list; /* Queued frames */
159 /* Data handling callback */
160 void (*data)(struct gsm_dlci *dlci, u8 *data, int len);
Russ Gorbybcd5abe2011-06-16 14:20:12 -0700161 void (*prev_data)(struct gsm_dlci *dlci, u8 *data, int len);
162 struct net_device *net; /* network interface, if created */
Alan Coxe1eaea42010-03-26 11:32:54 +0000163};
164
165/* DLCI 0, 62/63 are special or reseved see gsmtty_open */
166
167#define NUM_DLCI 64
168
169/*
170 * DLCI 0 is used to pass control blocks out of band of the data
171 * flow (and with a higher link priority). One command can be outstanding
172 * at a time and we use this structure to manage them. They are created
173 * and destroyed by the user context, and updated by the receive paths
174 * and timers
175 */
176
177struct gsm_control {
178 u8 cmd; /* Command we are issuing */
179 u8 *data; /* Data for the command in case we retransmit */
180 int len; /* Length of block for retransmission */
181 int done; /* Done flag */
182 int error; /* Error if any */
183};
184
185/*
186 * Each GSM mux we have is represented by this structure. If we are
187 * operating as an ldisc then we use this structure as our ldisc
188 * state. We need to sort out lifetimes and locking with respect
189 * to the gsm mux array. For now we don't free DLCI objects that
190 * have been instantiated until the mux itself is terminated.
191 *
192 * To consider further: tty open versus mux shutdown.
193 */
194
195struct gsm_mux {
196 struct tty_struct *tty; /* The tty our ldisc is bound to */
197 spinlock_t lock;
Russ Gorbyd50f6dc2011-06-14 13:35:32 -0700198 unsigned int num;
Russ Gorby6ab8fba2011-06-16 14:20:13 -0700199 struct kref ref;
Alan Coxe1eaea42010-03-26 11:32:54 +0000200
201 /* Events on the GSM channel */
202 wait_queue_head_t event;
203
204 /* Bits for GSM mode decoding */
205
206 /* Framing Layer */
207 unsigned char *buf;
208 int state;
209#define GSM_SEARCH 0
210#define GSM_START 1
211#define GSM_ADDRESS 2
212#define GSM_CONTROL 3
213#define GSM_LEN 4
214#define GSM_DATA 5
215#define GSM_FCS 6
216#define GSM_OVERRUN 7
Alan Coxc2f2f002010-11-04 15:17:03 +0000217#define GSM_LEN0 8
218#define GSM_LEN1 9
219#define GSM_SSOF 10
Alan Coxe1eaea42010-03-26 11:32:54 +0000220 unsigned int len;
221 unsigned int address;
222 unsigned int count;
223 int escape;
224 int encoding;
225 u8 control;
226 u8 fcs;
Alan Coxc2f2f002010-11-04 15:17:03 +0000227 u8 received_fcs;
Alan Coxe1eaea42010-03-26 11:32:54 +0000228 u8 *txframe; /* TX framing buffer */
229
230 /* Methods for the receiver side */
231 void (*receive)(struct gsm_mux *gsm, u8 ch);
232 void (*error)(struct gsm_mux *gsm, u8 ch, u8 flag);
233 /* And transmit side */
234 int (*output)(struct gsm_mux *mux, u8 *data, int len);
235
236 /* Link Layer */
237 unsigned int mru;
238 unsigned int mtu;
239 int initiator; /* Did we initiate connection */
240 int dead; /* Has the mux been shut down */
241 struct gsm_dlci *dlci[NUM_DLCI];
242 int constipated; /* Asked by remote to shut up */
243
244 spinlock_t tx_lock;
245 unsigned int tx_bytes; /* TX data outstanding */
246#define TX_THRESH_HI 8192
247#define TX_THRESH_LO 2048
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;
811 while(1) {
812 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;
831 case 2: /* Unstructed with modem bits. Always one byte as we never
832 send inline break data */
833 *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
samix.lebsir10c6c382012-08-13 13:44:22 +0100972 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)
985 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);
1071 if (brk & 0x01)
1072 tty_insert_flip_char(tty, 0, TTY_BREAK);
1073 }
1074 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;
1093 struct gsm_dlci *dlci;
1094 int len = clen;
1095 u8 *dp = data;
1096 struct tty_struct *tty;
1097
1098 while (gsm_read_ea(&addr, *dp++) == 0) {
1099 len--;
1100 if (len == 0)
1101 return;
1102 }
1103 /* Must be at least one byte following the EA */
1104 len--;
1105 if (len <= 0)
1106 return;
1107
1108 addr >>= 1;
1109 /* Closed port, or invalid ? */
1110 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1111 return;
1112 dlci = gsm->dlci[addr];
1113
1114 while (gsm_read_ea(&modem, *dp++) == 0) {
1115 len--;
1116 if (len == 0)
1117 return;
1118 }
1119 tty = tty_port_tty_get(&dlci->port);
Russ Gorby72632872011-06-14 13:23:28 -07001120 gsm_process_modem(tty, dlci, modem, clen);
Alan Coxe1eaea42010-03-26 11:32:54 +00001121 if (tty) {
1122 tty_wakeup(tty);
1123 tty_kref_put(tty);
1124 }
1125 gsm_control_reply(gsm, CMD_MSC, data, clen);
1126}
1127
1128/**
1129 * gsm_control_rls - remote line status
1130 * @gsm: GSM channel
1131 * @data: data bytes
1132 * @clen: data length
1133 *
1134 * The modem sends us a two byte message on the control channel whenever
1135 * it wishes to send us an error state from the virtual link. Stuff
1136 * this into the uplink tty if present
1137 */
1138
1139static void gsm_control_rls(struct gsm_mux *gsm, u8 *data, int clen)
1140{
1141 struct tty_struct *tty;
1142 unsigned int addr = 0 ;
1143 u8 bits;
1144 int len = clen;
1145 u8 *dp = data;
1146
1147 while (gsm_read_ea(&addr, *dp++) == 0) {
1148 len--;
1149 if (len == 0)
1150 return;
1151 }
1152 /* Must be at least one byte following ea */
1153 len--;
1154 if (len <= 0)
1155 return;
1156 addr >>= 1;
1157 /* Closed port, or invalid ? */
1158 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1159 return;
1160 /* No error ? */
1161 bits = *dp;
1162 if ((bits & 1) == 0)
1163 return;
1164 /* See if we have an uplink tty */
1165 tty = tty_port_tty_get(&gsm->dlci[addr]->port);
1166
1167 if (tty) {
1168 if (bits & 2)
1169 tty_insert_flip_char(tty, 0, TTY_OVERRUN);
1170 if (bits & 4)
1171 tty_insert_flip_char(tty, 0, TTY_PARITY);
1172 if (bits & 8)
1173 tty_insert_flip_char(tty, 0, TTY_FRAME);
1174 tty_flip_buffer_push(tty);
1175 tty_kref_put(tty);
1176 }
1177 gsm_control_reply(gsm, CMD_RLS, data, clen);
1178}
1179
1180static void gsm_dlci_begin_close(struct gsm_dlci *dlci);
1181
1182/**
1183 * gsm_control_message - DLCI 0 control processing
1184 * @gsm: our GSM mux
1185 * @command: the command EA
1186 * @data: data beyond the command/length EAs
1187 * @clen: length
1188 *
1189 * Input processor for control messages from the other end of the link.
1190 * Processes the incoming request and queues a response frame or an
1191 * NSC response if not supported
1192 */
1193
1194static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
1195 u8 *data, int clen)
1196{
1197 u8 buf[1];
Russ Gorby5e447082012-08-13 13:44:40 +01001198 unsigned long flags;
1199
Alan Coxe1eaea42010-03-26 11:32:54 +00001200 switch (command) {
1201 case CMD_CLD: {
1202 struct gsm_dlci *dlci = gsm->dlci[0];
1203 /* Modem wishes to close down */
1204 if (dlci) {
1205 dlci->dead = 1;
1206 gsm->dead = 1;
1207 gsm_dlci_begin_close(dlci);
1208 }
1209 }
1210 break;
1211 case CMD_TEST:
1212 /* Modem wishes to test, reply with the data */
1213 gsm_control_reply(gsm, CMD_TEST, data, clen);
1214 break;
1215 case CMD_FCON:
Alan Coxe1eaea42010-03-26 11:32:54 +00001216 /* Modem can accept data again */
1217 gsm->constipated = 0;
Frederic Beratc01af4f2012-08-13 13:43:58 +01001218 gsm_control_reply(gsm, CMD_FCON, NULL, 0);
Alan Coxe1eaea42010-03-26 11:32:54 +00001219 /* Kick the link in case it is idling */
Russ Gorby5e447082012-08-13 13:44:40 +01001220 spin_lock_irqsave(&gsm->tx_lock, flags);
Alan Coxe1eaea42010-03-26 11:32:54 +00001221 gsm_data_kick(gsm);
Russ Gorby5e447082012-08-13 13:44:40 +01001222 spin_unlock_irqrestore(&gsm->tx_lock, flags);
Alan Coxe1eaea42010-03-26 11:32:54 +00001223 break;
Frederic Beratc01af4f2012-08-13 13:43:58 +01001224 case CMD_FCOFF:
1225 /* Modem wants us to STFU */
Frederic Beratc01af4f2012-08-13 13:43:58 +01001226 gsm->constipated = 1;
1227 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0);
1228 break;
Alan Coxe1eaea42010-03-26 11:32:54 +00001229 case CMD_MSC:
1230 /* Out of band modem line change indicator for a DLCI */
1231 gsm_control_modem(gsm, data, clen);
1232 break;
1233 case CMD_RLS:
1234 /* Out of band error reception for a DLCI */
1235 gsm_control_rls(gsm, data, clen);
1236 break;
1237 case CMD_PSC:
1238 /* Modem wishes to enter power saving state */
1239 gsm_control_reply(gsm, CMD_PSC, NULL, 0);
1240 break;
1241 /* Optional unsupported commands */
1242 case CMD_PN: /* Parameter negotiation */
Lucas De Marchi25985ed2011-03-30 22:57:33 -03001243 case CMD_RPN: /* Remote port negotiation */
1244 case CMD_SNC: /* Service negotiation command */
Alan Coxe1eaea42010-03-26 11:32:54 +00001245 default:
1246 /* Reply to bad commands with an NSC */
1247 buf[0] = command;
1248 gsm_control_reply(gsm, CMD_NSC, buf, 1);
1249 break;
1250 }
1251}
1252
1253/**
1254 * gsm_control_response - process a response to our control
1255 * @gsm: our GSM mux
1256 * @command: the command (response) EA
1257 * @data: data beyond the command/length EA
1258 * @clen: length
1259 *
1260 * Process a response to an outstanding command. We only allow a single
1261 * control message in flight so this is fairly easy. All the clean up
1262 * is done by the caller, we just update the fields, flag it as done
1263 * and return
1264 */
1265
1266static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
1267 u8 *data, int clen)
1268{
1269 struct gsm_control *ctrl;
1270 unsigned long flags;
1271
1272 spin_lock_irqsave(&gsm->control_lock, flags);
1273
1274 ctrl = gsm->pending_cmd;
1275 /* Does the reply match our command */
1276 command |= 1;
1277 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) {
1278 /* Our command was replied to, kill the retry timer */
1279 del_timer(&gsm->t2_timer);
1280 gsm->pending_cmd = NULL;
1281 /* Rejected by the other end */
1282 if (command == CMD_NSC)
1283 ctrl->error = -EOPNOTSUPP;
1284 ctrl->done = 1;
1285 wake_up(&gsm->event);
1286 }
1287 spin_unlock_irqrestore(&gsm->control_lock, flags);
1288}
1289
1290/**
Alan Cox5f9a31d2010-11-04 15:17:27 +00001291 * gsm_control_transmit - send control packet
Alan Coxe1eaea42010-03-26 11:32:54 +00001292 * @gsm: gsm mux
1293 * @ctrl: frame to send
1294 *
1295 * Send out a pending control command (called under control lock)
1296 */
1297
1298static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl)
1299{
Eric Bénarded43b472011-03-09 19:24:49 +01001300 struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, gsm->ftype);
Alan Coxe1eaea42010-03-26 11:32:54 +00001301 if (msg == NULL)
1302 return;
1303 msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */
1304 memcpy(msg->data + 1, ctrl->data, ctrl->len);
1305 gsm_data_queue(gsm->dlci[0], msg);
1306}
1307
1308/**
1309 * gsm_control_retransmit - retransmit a control frame
1310 * @data: pointer to our gsm object
1311 *
1312 * Called off the T2 timer expiry in order to retransmit control frames
1313 * that have been lost in the system somewhere. The control_lock protects
1314 * us from colliding with another sender or a receive completion event.
1315 * In that situation the timer may still occur in a small window but
1316 * gsm->pending_cmd will be NULL and we just let the timer expire.
1317 */
1318
1319static void gsm_control_retransmit(unsigned long data)
1320{
1321 struct gsm_mux *gsm = (struct gsm_mux *)data;
1322 struct gsm_control *ctrl;
1323 unsigned long flags;
1324 spin_lock_irqsave(&gsm->control_lock, flags);
1325 ctrl = gsm->pending_cmd;
1326 if (ctrl) {
1327 gsm->cretries--;
1328 if (gsm->cretries == 0) {
1329 gsm->pending_cmd = NULL;
1330 ctrl->error = -ETIMEDOUT;
1331 ctrl->done = 1;
1332 spin_unlock_irqrestore(&gsm->control_lock, flags);
1333 wake_up(&gsm->event);
1334 return;
1335 }
1336 gsm_control_transmit(gsm, ctrl);
1337 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1338 }
1339 spin_unlock_irqrestore(&gsm->control_lock, flags);
1340}
1341
1342/**
1343 * gsm_control_send - send a control frame on DLCI 0
1344 * @gsm: the GSM channel
1345 * @command: command to send including CR bit
1346 * @data: bytes of data (must be kmalloced)
1347 * @len: length of the block to send
1348 *
1349 * Queue and dispatch a control command. Only one command can be
1350 * active at a time. In theory more can be outstanding but the matching
1351 * gets really complicated so for now stick to one outstanding.
1352 */
1353
1354static struct gsm_control *gsm_control_send(struct gsm_mux *gsm,
1355 unsigned int command, u8 *data, int clen)
1356{
1357 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control),
1358 GFP_KERNEL);
1359 unsigned long flags;
1360 if (ctrl == NULL)
1361 return NULL;
1362retry:
1363 wait_event(gsm->event, gsm->pending_cmd == NULL);
1364 spin_lock_irqsave(&gsm->control_lock, flags);
1365 if (gsm->pending_cmd != NULL) {
1366 spin_unlock_irqrestore(&gsm->control_lock, flags);
1367 goto retry;
1368 }
1369 ctrl->cmd = command;
1370 ctrl->data = data;
1371 ctrl->len = clen;
1372 gsm->pending_cmd = ctrl;
1373 gsm->cretries = gsm->n2;
1374 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1375 gsm_control_transmit(gsm, ctrl);
1376 spin_unlock_irqrestore(&gsm->control_lock, flags);
1377 return ctrl;
1378}
1379
1380/**
1381 * gsm_control_wait - wait for a control to finish
1382 * @gsm: GSM mux
1383 * @control: control we are waiting on
1384 *
1385 * Waits for the control to complete or time out. Frees any used
1386 * resources and returns 0 for success, or an error if the remote
1387 * rejected or ignored the request.
1388 */
1389
1390static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
1391{
1392 int err;
1393 wait_event(gsm->event, control->done == 1);
1394 err = control->error;
1395 kfree(control);
1396 return err;
1397}
1398
1399
1400/*
1401 * DLCI level handling: Needs krefs
1402 */
1403
1404/*
1405 * State transitions and timers
1406 */
1407
1408/**
1409 * gsm_dlci_close - a DLCI has closed
1410 * @dlci: DLCI that closed
1411 *
1412 * Perform processing when moving a DLCI into closed state. If there
1413 * is an attached tty this is hung up
1414 */
1415
1416static void gsm_dlci_close(struct gsm_dlci *dlci)
1417{
1418 del_timer(&dlci->t1);
1419 if (debug & 8)
Alan Cox5f9a31d2010-11-04 15:17:27 +00001420 pr_debug("DLCI %d goes closed.\n", dlci->addr);
Alan Coxe1eaea42010-03-26 11:32:54 +00001421 dlci->state = DLCI_CLOSED;
1422 if (dlci->addr != 0) {
1423 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1424 if (tty) {
1425 tty_hangup(tty);
1426 tty_kref_put(tty);
1427 }
1428 kfifo_reset(dlci->fifo);
1429 } else
1430 dlci->gsm->dead = 1;
1431 wake_up(&dlci->gsm->event);
1432 /* A DLCI 0 close is a MUX termination so we need to kick that
1433 back to userspace somehow */
1434}
1435
1436/**
1437 * gsm_dlci_open - a DLCI has opened
1438 * @dlci: DLCI that opened
1439 *
1440 * Perform processing when moving a DLCI into open state.
1441 */
1442
1443static void gsm_dlci_open(struct gsm_dlci *dlci)
1444{
1445 /* Note that SABM UA .. SABM UA first UA lost can mean that we go
1446 open -> open */
1447 del_timer(&dlci->t1);
1448 /* This will let a tty open continue */
1449 dlci->state = DLCI_OPEN;
1450 if (debug & 8)
Alan Cox5f9a31d2010-11-04 15:17:27 +00001451 pr_debug("DLCI %d goes open.\n", dlci->addr);
Alan Coxe1eaea42010-03-26 11:32:54 +00001452 wake_up(&dlci->gsm->event);
1453}
1454
1455/**
1456 * gsm_dlci_t1 - T1 timer expiry
1457 * @dlci: DLCI that opened
1458 *
1459 * The T1 timer handles retransmits of control frames (essentially of
1460 * SABM and DISC). We resend the command until the retry count runs out
1461 * in which case an opening port goes back to closed and a closing port
1462 * is simply put into closed state (any further frames from the other
1463 * end will get a DM response)
1464 */
1465
1466static void gsm_dlci_t1(unsigned long data)
1467{
1468 struct gsm_dlci *dlci = (struct gsm_dlci *)data;
1469 struct gsm_mux *gsm = dlci->gsm;
1470
1471 switch (dlci->state) {
1472 case DLCI_OPENING:
1473 dlci->retries--;
1474 if (dlci->retries) {
1475 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1476 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1477 } else
1478 gsm_dlci_close(dlci);
1479 break;
1480 case DLCI_CLOSING:
1481 dlci->retries--;
1482 if (dlci->retries) {
1483 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1484 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1485 } else
1486 gsm_dlci_close(dlci);
1487 break;
1488 }
1489}
1490
1491/**
1492 * gsm_dlci_begin_open - start channel open procedure
1493 * @dlci: DLCI to open
1494 *
1495 * Commence opening a DLCI from the Linux side. We issue SABM messages
1496 * to the modem which should then reply with a UA, at which point we
1497 * will move into open state. Opening is done asynchronously with retry
1498 * running off timers and the responses.
1499 */
1500
1501static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
1502{
1503 struct gsm_mux *gsm = dlci->gsm;
1504 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING)
1505 return;
1506 dlci->retries = gsm->n2;
1507 dlci->state = DLCI_OPENING;
1508 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1509 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1510}
1511
1512/**
1513 * gsm_dlci_begin_close - start channel open procedure
1514 * @dlci: DLCI to open
1515 *
1516 * Commence closing a DLCI from the Linux side. We issue DISC messages
1517 * to the modem which should then reply with a UA, at which point we
1518 * will move into closed state. Closing is done asynchronously with retry
1519 * off timers. We may also receive a DM reply from the other end which
1520 * indicates the channel was already closed.
1521 */
1522
1523static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
1524{
1525 struct gsm_mux *gsm = dlci->gsm;
1526 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
1527 return;
1528 dlci->retries = gsm->n2;
1529 dlci->state = DLCI_CLOSING;
1530 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1531 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1532}
1533
1534/**
1535 * gsm_dlci_data - data arrived
1536 * @dlci: channel
1537 * @data: block of bytes received
1538 * @len: length of received block
1539 *
1540 * A UI or UIH frame has arrived which contains data for a channel
1541 * other than the control channel. If the relevant virtual tty is
1542 * open we shovel the bits down it, if not we drop them.
1543 */
1544
Russ Gorby72632872011-06-14 13:23:28 -07001545static void gsm_dlci_data(struct gsm_dlci *dlci, u8 *data, int clen)
Alan Coxe1eaea42010-03-26 11:32:54 +00001546{
1547 /* krefs .. */
1548 struct tty_port *port = &dlci->port;
1549 struct tty_struct *tty = tty_port_tty_get(port);
1550 unsigned int modem = 0;
Russ Gorby72632872011-06-14 13:23:28 -07001551 int len = clen;
Alan Coxe1eaea42010-03-26 11:32:54 +00001552
1553 if (debug & 16)
Alan Cox5f9a31d2010-11-04 15:17:27 +00001554 pr_debug("%d bytes for tty %p\n", len, tty);
Alan Coxe1eaea42010-03-26 11:32:54 +00001555 if (tty) {
1556 switch (dlci->adaption) {
Alan Cox5f9a31d2010-11-04 15:17:27 +00001557 /* Unsupported types */
1558 /* Packetised interruptible data */
1559 case 4:
1560 break;
1561 /* Packetised uininterruptible voice/data */
1562 case 3:
1563 break;
1564 /* Asynchronous serial with line state in each frame */
1565 case 2:
1566 while (gsm_read_ea(&modem, *data++) == 0) {
1567 len--;
1568 if (len == 0)
1569 return;
1570 }
Russ Gorby72632872011-06-14 13:23:28 -07001571 gsm_process_modem(tty, dlci, modem, clen);
Alan Cox5f9a31d2010-11-04 15:17:27 +00001572 /* Line state will go via DLCI 0 controls only */
1573 case 1:
1574 default:
1575 tty_insert_flip_string(tty, data, len);
1576 tty_flip_buffer_push(tty);
Alan Coxe1eaea42010-03-26 11:32:54 +00001577 }
1578 tty_kref_put(tty);
1579 }
1580}
1581
1582/**
1583 * gsm_dlci_control - data arrived on control channel
1584 * @dlci: channel
1585 * @data: block of bytes received
1586 * @len: length of received block
1587 *
1588 * A UI or UIH frame has arrived which contains data for DLCI 0 the
1589 * control channel. This should contain a command EA followed by
1590 * control data bytes. The command EA contains a command/response bit
1591 * and we divide up the work accordingly.
1592 */
1593
1594static void gsm_dlci_command(struct gsm_dlci *dlci, u8 *data, int len)
1595{
1596 /* See what command is involved */
1597 unsigned int command = 0;
1598 while (len-- > 0) {
1599 if (gsm_read_ea(&command, *data++) == 1) {
1600 int clen = *data++;
1601 len--;
1602 /* FIXME: this is properly an EA */
1603 clen >>= 1;
1604 /* Malformed command ? */
1605 if (clen > len)
1606 return;
1607 if (command & 1)
1608 gsm_control_message(dlci->gsm, command,
1609 data, clen);
1610 else
1611 gsm_control_response(dlci->gsm, command,
1612 data, clen);
1613 return;
1614 }
1615 }
1616}
1617
1618/*
1619 * Allocate/Free DLCI channels
1620 */
1621
1622/**
1623 * gsm_dlci_alloc - allocate a DLCI
1624 * @gsm: GSM mux
1625 * @addr: address of the DLCI
1626 *
1627 * Allocate and install a new DLCI object into the GSM mux.
1628 *
1629 * FIXME: review locking races
1630 */
1631
1632static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
1633{
1634 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC);
1635 if (dlci == NULL)
1636 return NULL;
1637 spin_lock_init(&dlci->lock);
Russ Gorby6ab8fba2011-06-16 14:20:13 -07001638 kref_init(&dlci->ref);
Russ Gorbybcd5abe2011-06-16 14:20:12 -07001639 mutex_init(&dlci->mutex);
Alan Coxe1eaea42010-03-26 11:32:54 +00001640 dlci->fifo = &dlci->_fifo;
1641 if (kfifo_alloc(&dlci->_fifo, 4096, GFP_KERNEL) < 0) {
1642 kfree(dlci);
1643 return NULL;
1644 }
1645
1646 skb_queue_head_init(&dlci->skb_list);
1647 init_timer(&dlci->t1);
1648 dlci->t1.function = gsm_dlci_t1;
1649 dlci->t1.data = (unsigned long)dlci;
1650 tty_port_init(&dlci->port);
1651 dlci->port.ops = &gsm_port_ops;
1652 dlci->gsm = gsm;
1653 dlci->addr = addr;
1654 dlci->adaption = gsm->adaption;
1655 dlci->state = DLCI_CLOSED;
1656 if (addr)
1657 dlci->data = gsm_dlci_data;
1658 else
1659 dlci->data = gsm_dlci_command;
1660 gsm->dlci[addr] = dlci;
1661 return dlci;
1662}
1663
1664/**
Russ Gorby6ab8fba2011-06-16 14:20:13 -07001665 * gsm_dlci_free - free DLCI
1666 * @dlci: DLCI to free
Alan Coxe1eaea42010-03-26 11:32:54 +00001667 *
Russ Gorby6ab8fba2011-06-16 14:20:13 -07001668 * Free up a DLCI.
Alan Coxe1eaea42010-03-26 11:32:54 +00001669 *
1670 * Can sleep.
1671 */
Russ Gorby6ab8fba2011-06-16 14:20:13 -07001672static void gsm_dlci_free(struct kref *ref)
1673{
1674 struct gsm_dlci *dlci = container_of(ref, struct gsm_dlci, ref);
1675
1676 del_timer_sync(&dlci->t1);
1677 dlci->gsm->dlci[dlci->addr] = NULL;
1678 kfifo_free(dlci->fifo);
1679 while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
Russ Gorby329e5672012-08-13 13:45:15 +01001680 dev_kfree_skb(dlci->skb);
Russ Gorby6ab8fba2011-06-16 14:20:13 -07001681 kfree(dlci);
1682}
1683
1684static inline void dlci_get(struct gsm_dlci *dlci)
1685{
1686 kref_get(&dlci->ref);
1687}
1688
1689static inline void dlci_put(struct gsm_dlci *dlci)
1690{
1691 kref_put(&dlci->ref, gsm_dlci_free);
1692}
1693
1694/**
1695 * gsm_dlci_release - release DLCI
1696 * @dlci: DLCI to destroy
1697 *
1698 * Release a DLCI. Actual free is deferred until either
1699 * mux is closed or tty is closed - whichever is last.
1700 *
1701 * Can sleep.
1702 */
1703static void gsm_dlci_release(struct gsm_dlci *dlci)
Alan Coxe1eaea42010-03-26 11:32:54 +00001704{
1705 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1706 if (tty) {
1707 tty_vhangup(tty);
1708 tty_kref_put(tty);
1709 }
Russ Gorby6ab8fba2011-06-16 14:20:13 -07001710 dlci_put(dlci);
Alan Coxe1eaea42010-03-26 11:32:54 +00001711}
1712
Alan Coxe1eaea42010-03-26 11:32:54 +00001713/*
1714 * LAPBish link layer logic
1715 */
1716
1717/**
1718 * gsm_queue - a GSM frame is ready to process
1719 * @gsm: pointer to our gsm mux
1720 *
1721 * At this point in time a frame has arrived and been demangled from
1722 * the line encoding. All the differences between the encodings have
1723 * been handled below us and the frame is unpacked into the structures.
1724 * The fcs holds the header FCS but any data FCS must be added here.
1725 */
1726
1727static void gsm_queue(struct gsm_mux *gsm)
1728{
1729 struct gsm_dlci *dlci;
1730 u8 cr;
1731 int address;
1732 /* We have to sneak a look at the packet body to do the FCS.
1733 A somewhat layering violation in the spec */
1734
1735 if ((gsm->control & ~PF) == UI)
1736 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len);
Mikhail Kshevetskiy9db4e432011-03-27 04:05:00 +04001737 if (gsm->encoding == 0){
1738 /* WARNING: gsm->received_fcs is used for gsm->encoding = 0 only.
1739 In this case it contain the last piece of data
1740 required to generate final CRC */
1741 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs);
1742 }
Alan Coxe1eaea42010-03-26 11:32:54 +00001743 if (gsm->fcs != GOOD_FCS) {
1744 gsm->bad_fcs++;
1745 if (debug & 4)
Alan Cox5f9a31d2010-11-04 15:17:27 +00001746 pr_debug("BAD FCS %02x\n", gsm->fcs);
Alan Coxe1eaea42010-03-26 11:32:54 +00001747 return;
1748 }
1749 address = gsm->address >> 1;
1750 if (address >= NUM_DLCI)
1751 goto invalid;
1752
1753 cr = gsm->address & 1; /* C/R bit */
1754
1755 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
1756
1757 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */
1758 dlci = gsm->dlci[address];
1759
1760 switch (gsm->control) {
1761 case SABM|PF:
1762 if (cr == 0)
1763 goto invalid;
1764 if (dlci == NULL)
1765 dlci = gsm_dlci_alloc(gsm, address);
1766 if (dlci == NULL)
1767 return;
1768 if (dlci->dead)
1769 gsm_response(gsm, address, DM);
1770 else {
1771 gsm_response(gsm, address, UA);
1772 gsm_dlci_open(dlci);
1773 }
1774 break;
1775 case DISC|PF:
1776 if (cr == 0)
1777 goto invalid;
1778 if (dlci == NULL || dlci->state == DLCI_CLOSED) {
1779 gsm_response(gsm, address, DM);
1780 return;
1781 }
1782 /* Real close complete */
1783 gsm_response(gsm, address, UA);
1784 gsm_dlci_close(dlci);
1785 break;
1786 case UA:
1787 case UA|PF:
1788 if (cr == 0 || dlci == NULL)
1789 break;
1790 switch (dlci->state) {
1791 case DLCI_CLOSING:
1792 gsm_dlci_close(dlci);
1793 break;
1794 case DLCI_OPENING:
1795 gsm_dlci_open(dlci);
1796 break;
1797 }
1798 break;
1799 case DM: /* DM can be valid unsolicited */
1800 case DM|PF:
1801 if (cr)
1802 goto invalid;
1803 if (dlci == NULL)
1804 return;
1805 gsm_dlci_close(dlci);
1806 break;
1807 case UI:
1808 case UI|PF:
1809 case UIH:
1810 case UIH|PF:
1811#if 0
1812 if (cr)
1813 goto invalid;
1814#endif
1815 if (dlci == NULL || dlci->state != DLCI_OPEN) {
1816 gsm_command(gsm, address, DM|PF);
1817 return;
1818 }
1819 dlci->data(dlci, gsm->buf, gsm->len);
1820 break;
1821 default:
1822 goto invalid;
1823 }
1824 return;
1825invalid:
1826 gsm->malformed++;
1827 return;
1828}
1829
1830
1831/**
1832 * gsm0_receive - perform processing for non-transparency
1833 * @gsm: gsm data for this ldisc instance
1834 * @c: character
1835 *
1836 * Receive bytes in gsm mode 0
1837 */
1838
1839static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
1840{
Alan Coxc2f2f002010-11-04 15:17:03 +00001841 unsigned int len;
1842
Alan Coxe1eaea42010-03-26 11:32:54 +00001843 switch (gsm->state) {
1844 case GSM_SEARCH: /* SOF marker */
1845 if (c == GSM0_SOF) {
1846 gsm->state = GSM_ADDRESS;
1847 gsm->address = 0;
1848 gsm->len = 0;
1849 gsm->fcs = INIT_FCS;
1850 }
Alan Coxc2f2f002010-11-04 15:17:03 +00001851 break;
1852 case GSM_ADDRESS: /* Address EA */
Alan Coxe1eaea42010-03-26 11:32:54 +00001853 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1854 if (gsm_read_ea(&gsm->address, c))
1855 gsm->state = GSM_CONTROL;
1856 break;
1857 case GSM_CONTROL: /* Control Byte */
1858 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1859 gsm->control = c;
Alan Coxc2f2f002010-11-04 15:17:03 +00001860 gsm->state = GSM_LEN0;
Alan Coxe1eaea42010-03-26 11:32:54 +00001861 break;
Alan Coxc2f2f002010-11-04 15:17:03 +00001862 case GSM_LEN0: /* Length EA */
Alan Coxe1eaea42010-03-26 11:32:54 +00001863 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1864 if (gsm_read_ea(&gsm->len, c)) {
1865 if (gsm->len > gsm->mru) {
1866 gsm->bad_size++;
1867 gsm->state = GSM_SEARCH;
1868 break;
1869 }
1870 gsm->count = 0;
Alan Coxc2f2f002010-11-04 15:17:03 +00001871 if (!gsm->len)
1872 gsm->state = GSM_FCS;
1873 else
1874 gsm->state = GSM_DATA;
1875 break;
Alan Coxe1eaea42010-03-26 11:32:54 +00001876 }
Alan Coxc2f2f002010-11-04 15:17:03 +00001877 gsm->state = GSM_LEN1;
1878 break;
1879 case GSM_LEN1:
1880 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1881 len = c;
1882 gsm->len |= len << 7;
1883 if (gsm->len > gsm->mru) {
1884 gsm->bad_size++;
1885 gsm->state = GSM_SEARCH;
1886 break;
1887 }
1888 gsm->count = 0;
1889 if (!gsm->len)
1890 gsm->state = GSM_FCS;
1891 else
1892 gsm->state = GSM_DATA;
Alan Coxe1eaea42010-03-26 11:32:54 +00001893 break;
1894 case GSM_DATA: /* Data */
1895 gsm->buf[gsm->count++] = c;
1896 if (gsm->count == gsm->len)
1897 gsm->state = GSM_FCS;
1898 break;
1899 case GSM_FCS: /* FCS follows the packet */
Alan Coxc2f2f002010-11-04 15:17:03 +00001900 gsm->received_fcs = c;
Alan Coxe1eaea42010-03-26 11:32:54 +00001901 gsm_queue(gsm);
Alan Coxc2f2f002010-11-04 15:17:03 +00001902 gsm->state = GSM_SSOF;
1903 break;
1904 case GSM_SSOF:
1905 if (c == GSM0_SOF) {
1906 gsm->state = GSM_SEARCH;
1907 break;
1908 }
Alan Coxe1eaea42010-03-26 11:32:54 +00001909 break;
1910 }
1911}
1912
1913/**
Alan Coxc2f2f002010-11-04 15:17:03 +00001914 * gsm1_receive - perform processing for non-transparency
Alan Coxe1eaea42010-03-26 11:32:54 +00001915 * @gsm: gsm data for this ldisc instance
1916 * @c: character
1917 *
1918 * Receive bytes in mode 1 (Advanced option)
1919 */
1920
1921static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
1922{
1923 if (c == GSM1_SOF) {
1924 /* EOF is only valid in frame if we have got to the data state
1925 and received at least one byte (the FCS) */
1926 if (gsm->state == GSM_DATA && gsm->count) {
1927 /* Extract the FCS */
1928 gsm->count--;
1929 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
1930 gsm->len = gsm->count;
1931 gsm_queue(gsm);
1932 gsm->state = GSM_START;
1933 return;
1934 }
1935 /* Any partial frame was a runt so go back to start */
1936 if (gsm->state != GSM_START) {
1937 gsm->malformed++;
1938 gsm->state = GSM_START;
1939 }
1940 /* A SOF in GSM_START means we are still reading idling or
1941 framing bytes */
1942 return;
1943 }
1944
1945 if (c == GSM1_ESCAPE) {
1946 gsm->escape = 1;
1947 return;
1948 }
1949
1950 /* Only an unescaped SOF gets us out of GSM search */
1951 if (gsm->state == GSM_SEARCH)
1952 return;
1953
1954 if (gsm->escape) {
1955 c ^= GSM1_ESCAPE_BITS;
1956 gsm->escape = 0;
1957 }
1958 switch (gsm->state) {
1959 case GSM_START: /* First byte after SOF */
1960 gsm->address = 0;
1961 gsm->state = GSM_ADDRESS;
1962 gsm->fcs = INIT_FCS;
1963 /* Drop through */
1964 case GSM_ADDRESS: /* Address continuation */
1965 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1966 if (gsm_read_ea(&gsm->address, c))
1967 gsm->state = GSM_CONTROL;
1968 break;
1969 case GSM_CONTROL: /* Control Byte */
1970 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1971 gsm->control = c;
1972 gsm->count = 0;
1973 gsm->state = GSM_DATA;
1974 break;
1975 case GSM_DATA: /* Data */
Alan Cox5f9a31d2010-11-04 15:17:27 +00001976 if (gsm->count > gsm->mru) { /* Allow one for the FCS */
Alan Coxe1eaea42010-03-26 11:32:54 +00001977 gsm->state = GSM_OVERRUN;
1978 gsm->bad_size++;
1979 } else
1980 gsm->buf[gsm->count++] = c;
1981 break;
1982 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */
1983 break;
1984 }
1985}
1986
1987/**
1988 * gsm_error - handle tty error
1989 * @gsm: ldisc data
1990 * @data: byte received (may be invalid)
1991 * @flag: error received
1992 *
1993 * Handle an error in the receipt of data for a frame. Currently we just
1994 * go back to hunting for a SOF.
1995 *
1996 * FIXME: better diagnostics ?
1997 */
1998
1999static void gsm_error(struct gsm_mux *gsm,
2000 unsigned char data, unsigned char flag)
2001{
2002 gsm->state = GSM_SEARCH;
2003 gsm->io_error++;
2004}
2005
2006/**
2007 * gsm_cleanup_mux - generic GSM protocol cleanup
2008 * @gsm: our mux
2009 *
2010 * Clean up the bits of the mux which are the same for all framing
2011 * protocols. Remove the mux from the mux table, stop all the timers
2012 * and then shut down each device hanging up the channels as we go.
2013 */
2014
2015void gsm_cleanup_mux(struct gsm_mux *gsm)
2016{
2017 int i;
2018 struct gsm_dlci *dlci = gsm->dlci[0];
Russ Gorby329e5672012-08-13 13:45:15 +01002019 struct gsm_msg *txq, *ntxq;
Alan Coxf17141f2011-08-26 11:28:11 +01002020 struct gsm_control *gc;
Alan Coxe1eaea42010-03-26 11:32:54 +00002021
2022 gsm->dead = 1;
2023
2024 spin_lock(&gsm_mux_lock);
2025 for (i = 0; i < MAX_MUX; i++) {
2026 if (gsm_mux[i] == gsm) {
2027 gsm_mux[i] = NULL;
2028 break;
2029 }
2030 }
2031 spin_unlock(&gsm_mux_lock);
2032 WARN_ON(i == MAX_MUX);
2033
Alan Coxf17141f2011-08-26 11:28:11 +01002034 /* In theory disconnecting DLCI 0 is sufficient but for some
2035 modems this is apparently not the case. */
2036 if (dlci) {
2037 gc = gsm_control_send(gsm, CMD_CLD, NULL, 0);
2038 if (gc)
2039 gsm_control_wait(gsm, gc);
2040 }
Alan Coxe1eaea42010-03-26 11:32:54 +00002041 del_timer_sync(&gsm->t2_timer);
2042 /* Now we are sure T2 has stopped */
2043 if (dlci) {
2044 dlci->dead = 1;
2045 gsm_dlci_begin_close(dlci);
2046 wait_event_interruptible(gsm->event,
2047 dlci->state == DLCI_CLOSED);
2048 }
2049 /* Free up any link layer users */
2050 for (i = 0; i < NUM_DLCI; i++)
2051 if (gsm->dlci[i])
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002052 gsm_dlci_release(gsm->dlci[i]);
Alan Coxe1eaea42010-03-26 11:32:54 +00002053 /* Now wipe the queues */
Russ Gorbyb4338e12012-08-13 13:44:59 +01002054 list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list)
Alan Coxe1eaea42010-03-26 11:32:54 +00002055 kfree(txq);
Russ Gorbyb4338e12012-08-13 13:44:59 +01002056 INIT_LIST_HEAD(&gsm->tx_list);
Alan Coxe1eaea42010-03-26 11:32:54 +00002057}
2058EXPORT_SYMBOL_GPL(gsm_cleanup_mux);
2059
2060/**
2061 * gsm_activate_mux - generic GSM setup
2062 * @gsm: our mux
2063 *
2064 * Set up the bits of the mux which are the same for all framing
2065 * protocols. Add the mux to the mux table so it can be opened and
2066 * finally kick off connecting to DLCI 0 on the modem.
2067 */
2068
2069int gsm_activate_mux(struct gsm_mux *gsm)
2070{
2071 struct gsm_dlci *dlci;
2072 int i = 0;
2073
2074 init_timer(&gsm->t2_timer);
2075 gsm->t2_timer.function = gsm_control_retransmit;
2076 gsm->t2_timer.data = (unsigned long)gsm;
2077 init_waitqueue_head(&gsm->event);
2078 spin_lock_init(&gsm->control_lock);
2079 spin_lock_init(&gsm->tx_lock);
2080
2081 if (gsm->encoding == 0)
2082 gsm->receive = gsm0_receive;
2083 else
2084 gsm->receive = gsm1_receive;
2085 gsm->error = gsm_error;
2086
2087 spin_lock(&gsm_mux_lock);
2088 for (i = 0; i < MAX_MUX; i++) {
2089 if (gsm_mux[i] == NULL) {
Russ Gorbyd50f6dc2011-06-14 13:35:32 -07002090 gsm->num = i;
Alan Coxe1eaea42010-03-26 11:32:54 +00002091 gsm_mux[i] = gsm;
2092 break;
2093 }
2094 }
2095 spin_unlock(&gsm_mux_lock);
2096 if (i == MAX_MUX)
2097 return -EBUSY;
2098
2099 dlci = gsm_dlci_alloc(gsm, 0);
2100 if (dlci == NULL)
2101 return -ENOMEM;
2102 gsm->dead = 0; /* Tty opens are now permissible */
2103 return 0;
2104}
2105EXPORT_SYMBOL_GPL(gsm_activate_mux);
2106
2107/**
2108 * gsm_free_mux - free up a mux
2109 * @mux: mux to free
2110 *
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002111 * Dispose of allocated resources for a dead mux
Alan Coxe1eaea42010-03-26 11:32:54 +00002112 */
2113void gsm_free_mux(struct gsm_mux *gsm)
2114{
2115 kfree(gsm->txframe);
2116 kfree(gsm->buf);
2117 kfree(gsm);
2118}
2119EXPORT_SYMBOL_GPL(gsm_free_mux);
2120
2121/**
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002122 * gsm_free_muxr - free up a mux
2123 * @mux: mux to free
2124 *
2125 * Dispose of allocated resources for a dead mux
2126 */
2127static void gsm_free_muxr(struct kref *ref)
2128{
2129 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref);
2130 gsm_free_mux(gsm);
2131}
2132
2133static inline void mux_get(struct gsm_mux *gsm)
2134{
2135 kref_get(&gsm->ref);
2136}
2137
2138static inline void mux_put(struct gsm_mux *gsm)
2139{
2140 kref_put(&gsm->ref, gsm_free_muxr);
2141}
2142
2143/**
Alan Coxe1eaea42010-03-26 11:32:54 +00002144 * gsm_alloc_mux - allocate a mux
2145 *
2146 * Creates a new mux ready for activation.
2147 */
2148
2149struct gsm_mux *gsm_alloc_mux(void)
2150{
2151 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
2152 if (gsm == NULL)
2153 return NULL;
2154 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL);
2155 if (gsm->buf == NULL) {
2156 kfree(gsm);
2157 return NULL;
2158 }
2159 gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL);
2160 if (gsm->txframe == NULL) {
2161 kfree(gsm->buf);
2162 kfree(gsm);
2163 return NULL;
2164 }
2165 spin_lock_init(&gsm->lock);
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002166 kref_init(&gsm->ref);
Russ Gorbyb4338e12012-08-13 13:44:59 +01002167 INIT_LIST_HEAD(&gsm->tx_list);
Alan Coxe1eaea42010-03-26 11:32:54 +00002168
2169 gsm->t1 = T1;
2170 gsm->t2 = T2;
2171 gsm->n2 = N2;
2172 gsm->ftype = UIH;
Alan Coxe1eaea42010-03-26 11:32:54 +00002173 gsm->adaption = 1;
2174 gsm->encoding = 1;
2175 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
2176 gsm->mtu = 64;
2177 gsm->dead = 1; /* Avoid early tty opens */
2178
2179 return gsm;
2180}
2181EXPORT_SYMBOL_GPL(gsm_alloc_mux);
2182
Alan Coxe1eaea42010-03-26 11:32:54 +00002183/**
2184 * gsmld_output - write to link
2185 * @gsm: our mux
2186 * @data: bytes to output
2187 * @len: size
2188 *
2189 * Write a block of data from the GSM mux to the data channel. This
2190 * will eventually be serialized from above but at the moment isn't.
2191 */
2192
2193static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
2194{
2195 if (tty_write_room(gsm->tty) < len) {
2196 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
2197 return -ENOSPC;
2198 }
Joe Perches0a77c4f2011-04-25 16:46:49 -07002199 if (debug & 4)
2200 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET,
2201 data, len);
Alan Coxe1eaea42010-03-26 11:32:54 +00002202 gsm->tty->ops->write(gsm->tty, data, len);
2203 return len;
2204}
2205
2206/**
2207 * gsmld_attach_gsm - mode set up
2208 * @tty: our tty structure
2209 * @gsm: our mux
2210 *
2211 * Set up the MUX for basic mode and commence connecting to the
2212 * modem. Currently called from the line discipline set up but
2213 * will need moving to an ioctl path.
2214 */
2215
2216static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2217{
Russ Gorbyd50f6dc2011-06-14 13:35:32 -07002218 int ret, i;
2219 int base = gsm->num << 6; /* Base for this MUX */
Alan Coxe1eaea42010-03-26 11:32:54 +00002220
2221 gsm->tty = tty_kref_get(tty);
2222 gsm->output = gsmld_output;
2223 ret = gsm_activate_mux(gsm);
2224 if (ret != 0)
2225 tty_kref_put(gsm->tty);
Russ Gorbyd50f6dc2011-06-14 13:35:32 -07002226 else {
2227 /* Don't register device 0 - this is the control channel and not
2228 a usable tty interface */
2229 for (i = 1; i < NUM_DLCI; i++)
2230 tty_register_device(gsm_tty_driver, base + i, NULL);
2231 }
Alan Coxe1eaea42010-03-26 11:32:54 +00002232 return ret;
2233}
2234
2235
2236/**
2237 * gsmld_detach_gsm - stop doing 0710 mux
Justin P. Mattock70f23fd2011-05-10 10:16:21 +02002238 * @tty: tty attached to the mux
Alan Coxe1eaea42010-03-26 11:32:54 +00002239 * @gsm: mux
2240 *
2241 * Shutdown and then clean up the resources used by the line discipline
2242 */
2243
2244static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2245{
Russ Gorbyd50f6dc2011-06-14 13:35:32 -07002246 int i;
2247 int base = gsm->num << 6; /* Base for this MUX */
2248
Alan Coxe1eaea42010-03-26 11:32:54 +00002249 WARN_ON(tty != gsm->tty);
Russ Gorbyd50f6dc2011-06-14 13:35:32 -07002250 for (i = 1; i < NUM_DLCI; i++)
2251 tty_unregister_device(gsm_tty_driver, base + i);
Alan Coxe1eaea42010-03-26 11:32:54 +00002252 gsm_cleanup_mux(gsm);
2253 tty_kref_put(gsm->tty);
2254 gsm->tty = NULL;
2255}
2256
Linus Torvalds55db4c62011-06-04 06:33:24 +09002257static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
2258 char *fp, int count)
Alan Coxe1eaea42010-03-26 11:32:54 +00002259{
2260 struct gsm_mux *gsm = tty->disc_data;
2261 const unsigned char *dp;
2262 char *f;
2263 int i;
2264 char buf[64];
2265 char flags;
2266
Joe Perches0a77c4f2011-04-25 16:46:49 -07002267 if (debug & 4)
2268 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET,
2269 cp, count);
Alan Coxe1eaea42010-03-26 11:32:54 +00002270
2271 for (i = count, dp = cp, f = fp; i; i--, dp++) {
2272 flags = *f++;
2273 switch (flags) {
2274 case TTY_NORMAL:
2275 gsm->receive(gsm, *dp);
2276 break;
2277 case TTY_OVERRUN:
2278 case TTY_BREAK:
2279 case TTY_PARITY:
2280 case TTY_FRAME:
2281 gsm->error(gsm, *dp, flags);
2282 break;
2283 default:
Frederic Beratc01af4f2012-08-13 13:43:58 +01002284 WARN_ONCE(1, "%s: unknown flag %d\n",
Alan Coxe1eaea42010-03-26 11:32:54 +00002285 tty_name(tty, buf), flags);
2286 break;
2287 }
2288 }
2289 /* FASYNC if needed ? */
2290 /* If clogged call tty_throttle(tty); */
2291}
2292
2293/**
2294 * gsmld_chars_in_buffer - report available bytes
2295 * @tty: tty device
2296 *
2297 * Report the number of characters buffered to be delivered to user
2298 * at this instant in time.
2299 *
2300 * Locking: gsm lock
2301 */
2302
2303static ssize_t gsmld_chars_in_buffer(struct tty_struct *tty)
2304{
2305 return 0;
2306}
2307
2308/**
2309 * gsmld_flush_buffer - clean input queue
2310 * @tty: terminal device
2311 *
2312 * Flush the input buffer. Called when the line discipline is
2313 * being closed, when the tty layer wants the buffer flushed (eg
2314 * at hangup).
2315 */
2316
2317static void gsmld_flush_buffer(struct tty_struct *tty)
2318{
2319}
2320
2321/**
2322 * gsmld_close - close the ldisc for this tty
2323 * @tty: device
2324 *
2325 * Called from the terminal layer when this line discipline is
2326 * being shut down, either because of a close or becsuse of a
2327 * discipline change. The function will not be called while other
2328 * ldisc methods are in progress.
2329 */
2330
2331static void gsmld_close(struct tty_struct *tty)
2332{
2333 struct gsm_mux *gsm = tty->disc_data;
2334
2335 gsmld_detach_gsm(tty, gsm);
2336
2337 gsmld_flush_buffer(tty);
2338 /* Do other clean up here */
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002339 mux_put(gsm);
Alan Coxe1eaea42010-03-26 11:32:54 +00002340}
2341
2342/**
2343 * gsmld_open - open an ldisc
2344 * @tty: terminal to open
2345 *
2346 * Called when this line discipline is being attached to the
2347 * terminal device. Can sleep. Called serialized so that no
2348 * other events will occur in parallel. No further open will occur
2349 * until a close.
2350 */
2351
2352static int gsmld_open(struct tty_struct *tty)
2353{
2354 struct gsm_mux *gsm;
2355
2356 if (tty->ops->write == NULL)
2357 return -EINVAL;
2358
2359 /* Attach our ldisc data */
2360 gsm = gsm_alloc_mux();
2361 if (gsm == NULL)
2362 return -ENOMEM;
2363
2364 tty->disc_data = gsm;
2365 tty->receive_room = 65536;
2366
2367 /* Attach the initial passive connection */
2368 gsm->encoding = 1;
2369 return gsmld_attach_gsm(tty, gsm);
2370}
2371
2372/**
2373 * gsmld_write_wakeup - asynchronous I/O notifier
2374 * @tty: tty device
2375 *
2376 * Required for the ptys, serial driver etc. since processes
2377 * that attach themselves to the master and rely on ASYNC
2378 * IO must be woken up
2379 */
2380
2381static void gsmld_write_wakeup(struct tty_struct *tty)
2382{
2383 struct gsm_mux *gsm = tty->disc_data;
Dan Carpenter328be392010-05-25 11:37:17 +02002384 unsigned long flags;
Alan Coxe1eaea42010-03-26 11:32:54 +00002385
2386 /* Queue poll */
2387 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
Russ Gorby5e447082012-08-13 13:44:40 +01002388 spin_lock_irqsave(&gsm->tx_lock, flags);
Alan Coxe1eaea42010-03-26 11:32:54 +00002389 gsm_data_kick(gsm);
Dan Carpenter328be392010-05-25 11:37:17 +02002390 if (gsm->tx_bytes < TX_THRESH_LO) {
Alan Coxe1eaea42010-03-26 11:32:54 +00002391 gsm_dlci_data_sweep(gsm);
Dan Carpenter328be392010-05-25 11:37:17 +02002392 }
Russ Gorby5e447082012-08-13 13:44:40 +01002393 spin_unlock_irqrestore(&gsm->tx_lock, flags);
Alan Coxe1eaea42010-03-26 11:32:54 +00002394}
2395
2396/**
2397 * gsmld_read - read function for tty
2398 * @tty: tty device
2399 * @file: file object
2400 * @buf: userspace buffer pointer
2401 * @nr: size of I/O
2402 *
2403 * Perform reads for the line discipline. We are guaranteed that the
2404 * line discipline will not be closed under us but we may get multiple
2405 * parallel readers and must handle this ourselves. We may also get
2406 * a hangup. Always called in user context, may sleep.
2407 *
2408 * This code must be sure never to sleep through a hangup.
2409 */
2410
2411static ssize_t gsmld_read(struct tty_struct *tty, struct file *file,
2412 unsigned char __user *buf, size_t nr)
2413{
2414 return -EOPNOTSUPP;
2415}
2416
2417/**
2418 * gsmld_write - write function for tty
2419 * @tty: tty device
2420 * @file: file object
2421 * @buf: userspace buffer pointer
2422 * @nr: size of I/O
2423 *
2424 * Called when the owner of the device wants to send a frame
2425 * itself (or some other control data). The data is transferred
2426 * as-is and must be properly framed and checksummed as appropriate
2427 * by userspace. Frames are either sent whole or not at all as this
2428 * avoids pain user side.
2429 */
2430
2431static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
2432 const unsigned char *buf, size_t nr)
2433{
2434 int space = tty_write_room(tty);
2435 if (space >= nr)
2436 return tty->ops->write(tty, buf, nr);
2437 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2438 return -ENOBUFS;
2439}
2440
2441/**
2442 * gsmld_poll - poll method for N_GSM0710
2443 * @tty: terminal device
2444 * @file: file accessing it
2445 * @wait: poll table
2446 *
2447 * Called when the line discipline is asked to poll() for data or
2448 * for special events. This code is not serialized with respect to
2449 * other events save open/close.
2450 *
2451 * This code must be sure never to sleep through a hangup.
2452 * Called without the kernel lock held - fine
2453 */
2454
2455static unsigned int gsmld_poll(struct tty_struct *tty, struct file *file,
2456 poll_table *wait)
2457{
2458 unsigned int mask = 0;
2459 struct gsm_mux *gsm = tty->disc_data;
2460
2461 poll_wait(file, &tty->read_wait, wait);
2462 poll_wait(file, &tty->write_wait, wait);
2463 if (tty_hung_up_p(file))
2464 mask |= POLLHUP;
2465 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
2466 mask |= POLLOUT | POLLWRNORM;
2467 if (gsm->dead)
2468 mask |= POLLHUP;
2469 return mask;
2470}
2471
2472static int gsmld_config(struct tty_struct *tty, struct gsm_mux *gsm,
2473 struct gsm_config *c)
2474{
2475 int need_close = 0;
2476 int need_restart = 0;
2477
2478 /* Stuff we don't support yet - UI or I frame transport, windowing */
Alan Cox5f9a31d2010-11-04 15:17:27 +00002479 if ((c->adaption != 1 && c->adaption != 2) || c->k)
Alan Coxe1eaea42010-03-26 11:32:54 +00002480 return -EOPNOTSUPP;
2481 /* Check the MRU/MTU range looks sane */
2482 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8)
2483 return -EINVAL;
2484 if (c->n2 < 3)
2485 return -EINVAL;
2486 if (c->encapsulation > 1) /* Basic, advanced, no I */
2487 return -EINVAL;
2488 if (c->initiator > 1)
2489 return -EINVAL;
2490 if (c->i == 0 || c->i > 2) /* UIH and UI only */
2491 return -EINVAL;
2492 /*
2493 * See what is needed for reconfiguration
2494 */
2495
2496 /* Timing fields */
2497 if (c->t1 != 0 && c->t1 != gsm->t1)
2498 need_restart = 1;
2499 if (c->t2 != 0 && c->t2 != gsm->t2)
2500 need_restart = 1;
2501 if (c->encapsulation != gsm->encoding)
2502 need_restart = 1;
2503 if (c->adaption != gsm->adaption)
2504 need_restart = 1;
2505 /* Requires care */
2506 if (c->initiator != gsm->initiator)
2507 need_close = 1;
2508 if (c->mru != gsm->mru)
2509 need_restart = 1;
2510 if (c->mtu != gsm->mtu)
2511 need_restart = 1;
2512
2513 /*
2514 * Close down what is needed, restart and initiate the new
2515 * configuration
2516 */
2517
2518 if (need_close || need_restart) {
2519 gsm_dlci_begin_close(gsm->dlci[0]);
2520 /* This will timeout if the link is down due to N2 expiring */
2521 wait_event_interruptible(gsm->event,
2522 gsm->dlci[0]->state == DLCI_CLOSED);
2523 if (signal_pending(current))
2524 return -EINTR;
2525 }
2526 if (need_restart)
2527 gsm_cleanup_mux(gsm);
2528
2529 gsm->initiator = c->initiator;
2530 gsm->mru = c->mru;
Ken Mills91f78f32011-01-25 14:17:45 +00002531 gsm->mtu = c->mtu;
Alan Coxe1eaea42010-03-26 11:32:54 +00002532 gsm->encoding = c->encapsulation;
2533 gsm->adaption = c->adaption;
Ken Mills820e62e2010-11-04 15:16:24 +00002534 gsm->n2 = c->n2;
Alan Coxe1eaea42010-03-26 11:32:54 +00002535
2536 if (c->i == 1)
2537 gsm->ftype = UIH;
2538 else if (c->i == 2)
2539 gsm->ftype = UI;
2540
2541 if (c->t1)
2542 gsm->t1 = c->t1;
2543 if (c->t2)
2544 gsm->t2 = c->t2;
2545
2546 /* FIXME: We need to separate activation/deactivation from adding
2547 and removing from the mux array */
2548 if (need_restart)
2549 gsm_activate_mux(gsm);
2550 if (gsm->initiator && need_close)
2551 gsm_dlci_begin_open(gsm->dlci[0]);
2552 return 0;
2553}
2554
2555static int gsmld_ioctl(struct tty_struct *tty, struct file *file,
2556 unsigned int cmd, unsigned long arg)
2557{
2558 struct gsm_config c;
2559 struct gsm_mux *gsm = tty->disc_data;
2560
2561 switch (cmd) {
2562 case GSMIOC_GETCONF:
2563 memset(&c, 0, sizeof(c));
2564 c.adaption = gsm->adaption;
2565 c.encapsulation = gsm->encoding;
2566 c.initiator = gsm->initiator;
2567 c.t1 = gsm->t1;
2568 c.t2 = gsm->t2;
2569 c.t3 = 0; /* Not supported */
2570 c.n2 = gsm->n2;
2571 if (gsm->ftype == UIH)
2572 c.i = 1;
2573 else
2574 c.i = 2;
Alan Cox5f9a31d2010-11-04 15:17:27 +00002575 pr_debug("Ftype %d i %d\n", gsm->ftype, c.i);
Alan Coxe1eaea42010-03-26 11:32:54 +00002576 c.mru = gsm->mru;
2577 c.mtu = gsm->mtu;
2578 c.k = 0;
2579 if (copy_to_user((void *)arg, &c, sizeof(c)))
2580 return -EFAULT;
2581 return 0;
2582 case GSMIOC_SETCONF:
2583 if (copy_from_user(&c, (void *)arg, sizeof(c)))
2584 return -EFAULT;
2585 return gsmld_config(tty, gsm, &c);
2586 default:
2587 return n_tty_ioctl_helper(tty, file, cmd, arg);
2588 }
2589}
2590
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002591/*
2592 * Network interface
2593 *
2594 */
2595
2596static int gsm_mux_net_open(struct net_device *net)
2597{
2598 pr_debug("%s called\n", __func__);
2599 netif_start_queue(net);
2600 return 0;
2601}
2602
2603static int gsm_mux_net_close(struct net_device *net)
2604{
2605 netif_stop_queue(net);
2606 return 0;
2607}
2608
2609static struct net_device_stats *gsm_mux_net_get_stats(struct net_device *net)
2610{
2611 return &((struct gsm_mux_net *)netdev_priv(net))->stats;
2612}
2613static void dlci_net_free(struct gsm_dlci *dlci)
2614{
2615 if (!dlci->net) {
2616 WARN_ON(1);
2617 return;
2618 }
2619 dlci->adaption = dlci->prev_adaption;
2620 dlci->data = dlci->prev_data;
2621 free_netdev(dlci->net);
2622 dlci->net = NULL;
2623}
2624static void net_free(struct kref *ref)
2625{
2626 struct gsm_mux_net *mux_net;
2627 struct gsm_dlci *dlci;
2628
2629 mux_net = container_of(ref, struct gsm_mux_net, ref);
2630 dlci = mux_net->dlci;
2631
2632 if (dlci->net) {
2633 unregister_netdev(dlci->net);
2634 dlci_net_free(dlci);
2635 }
2636}
2637
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002638static inline void muxnet_get(struct gsm_mux_net *mux_net)
2639{
2640 kref_get(&mux_net->ref);
2641}
2642
2643static inline void muxnet_put(struct gsm_mux_net *mux_net)
2644{
2645 kref_put(&mux_net->ref, net_free);
2646}
2647
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002648static int gsm_mux_net_start_xmit(struct sk_buff *skb,
2649 struct net_device *net)
2650{
2651 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
2652 struct gsm_dlci *dlci = mux_net->dlci;
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002653 muxnet_get(mux_net);
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002654
2655 skb_queue_head(&dlci->skb_list, skb);
2656 STATS(net).tx_packets++;
2657 STATS(net).tx_bytes += skb->len;
2658 gsm_dlci_data_kick(dlci);
2659 /* And tell the kernel when the last transmit started. */
2660 net->trans_start = jiffies;
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002661 muxnet_put(mux_net);
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002662 return NETDEV_TX_OK;
2663}
2664
2665/* called when a packet did not ack after watchdogtimeout */
2666static void gsm_mux_net_tx_timeout(struct net_device *net)
2667{
2668 /* Tell syslog we are hosed. */
2669 dev_dbg(&net->dev, "Tx timed out.\n");
2670
2671 /* Update statistics */
2672 STATS(net).tx_errors++;
2673}
2674
2675static void gsm_mux_rx_netchar(struct gsm_dlci *dlci,
2676 unsigned char *in_buf, int size)
2677{
2678 struct net_device *net = dlci->net;
2679 struct sk_buff *skb;
2680 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002681 muxnet_get(mux_net);
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002682
2683 /* Allocate an sk_buff */
2684 skb = dev_alloc_skb(size + NET_IP_ALIGN);
2685 if (!skb) {
2686 /* We got no receive buffer. */
2687 STATS(net).rx_dropped++;
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002688 muxnet_put(mux_net);
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002689 return;
2690 }
2691 skb_reserve(skb, NET_IP_ALIGN);
2692 memcpy(skb_put(skb, size), in_buf, size);
2693
2694 skb->dev = net;
2695 skb->protocol = __constant_htons(ETH_P_IP);
2696
2697 /* Ship it off to the kernel */
2698 netif_rx(skb);
2699
2700 /* update out statistics */
2701 STATS(net).rx_packets++;
2702 STATS(net).rx_bytes += size;
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002703 muxnet_put(mux_net);
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002704 return;
2705}
2706
2707int gsm_change_mtu(struct net_device *net, int new_mtu)
2708{
2709 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
2710 if ((new_mtu < 8) || (new_mtu > mux_net->dlci->gsm->mtu))
2711 return -EINVAL;
2712 net->mtu = new_mtu;
2713 return 0;
2714}
2715
2716static void gsm_mux_net_init(struct net_device *net)
2717{
2718 static const struct net_device_ops gsm_netdev_ops = {
2719 .ndo_open = gsm_mux_net_open,
2720 .ndo_stop = gsm_mux_net_close,
2721 .ndo_start_xmit = gsm_mux_net_start_xmit,
2722 .ndo_tx_timeout = gsm_mux_net_tx_timeout,
2723 .ndo_get_stats = gsm_mux_net_get_stats,
2724 .ndo_change_mtu = gsm_change_mtu,
2725 };
2726
2727 net->netdev_ops = &gsm_netdev_ops;
2728
2729 /* fill in the other fields */
2730 net->watchdog_timeo = GSM_NET_TX_TIMEOUT;
2731 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
2732 net->type = ARPHRD_NONE;
2733 net->tx_queue_len = 10;
2734}
2735
2736
2737/* caller holds the dlci mutex */
2738static void gsm_destroy_network(struct gsm_dlci *dlci)
2739{
2740 struct gsm_mux_net *mux_net;
2741
2742 pr_debug("destroy network interface");
2743 if (!dlci->net)
2744 return;
2745 mux_net = (struct gsm_mux_net *)netdev_priv(dlci->net);
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002746 muxnet_put(mux_net);
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002747}
2748
2749
2750/* caller holds the dlci mutex */
2751static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
2752{
2753 char *netname;
2754 int retval = 0;
2755 struct net_device *net;
2756 struct gsm_mux_net *mux_net;
2757
2758 if (!capable(CAP_NET_ADMIN))
2759 return -EPERM;
2760
2761 /* Already in a non tty mode */
2762 if (dlci->adaption > 2)
2763 return -EBUSY;
2764
2765 if (nc->protocol != htons(ETH_P_IP))
2766 return -EPROTONOSUPPORT;
2767
2768 if (nc->adaption != 3 && nc->adaption != 4)
2769 return -EPROTONOSUPPORT;
2770
2771 pr_debug("create network interface");
2772
2773 netname = "gsm%d";
2774 if (nc->if_name[0] != '\0')
2775 netname = nc->if_name;
2776 net = alloc_netdev(sizeof(struct gsm_mux_net),
2777 netname,
2778 gsm_mux_net_init);
2779 if (!net) {
2780 pr_err("alloc_netdev failed");
2781 return -ENOMEM;
2782 }
2783 net->mtu = dlci->gsm->mtu;
2784 mux_net = (struct gsm_mux_net *)netdev_priv(net);
2785 mux_net->dlci = dlci;
2786 kref_init(&mux_net->ref);
2787 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */
2788
2789 /* reconfigure dlci for network */
2790 dlci->prev_adaption = dlci->adaption;
2791 dlci->prev_data = dlci->data;
2792 dlci->adaption = nc->adaption;
2793 dlci->data = gsm_mux_rx_netchar;
2794 dlci->net = net;
2795
2796 pr_debug("register netdev");
2797 retval = register_netdev(net);
2798 if (retval) {
2799 pr_err("network register fail %d\n", retval);
2800 dlci_net_free(dlci);
2801 return retval;
2802 }
2803 return net->ifindex; /* return network index */
2804}
Alan Coxe1eaea42010-03-26 11:32:54 +00002805
2806/* Line discipline for real tty */
2807struct tty_ldisc_ops tty_ldisc_packet = {
2808 .owner = THIS_MODULE,
2809 .magic = TTY_LDISC_MAGIC,
2810 .name = "n_gsm",
2811 .open = gsmld_open,
2812 .close = gsmld_close,
2813 .flush_buffer = gsmld_flush_buffer,
2814 .chars_in_buffer = gsmld_chars_in_buffer,
2815 .read = gsmld_read,
2816 .write = gsmld_write,
2817 .ioctl = gsmld_ioctl,
2818 .poll = gsmld_poll,
2819 .receive_buf = gsmld_receive_buf,
2820 .write_wakeup = gsmld_write_wakeup
2821};
2822
2823/*
2824 * Virtual tty side
2825 */
2826
2827#define TX_SIZE 512
2828
2829static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk)
2830{
2831 u8 modembits[5];
2832 struct gsm_control *ctrl;
2833 int len = 2;
2834
2835 if (brk)
2836 len++;
2837
2838 modembits[0] = len << 1 | EA; /* Data bytes */
2839 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */
2840 modembits[2] = gsm_encode_modem(dlci) << 1 | EA;
2841 if (brk)
2842 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */
2843 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1);
2844 if (ctrl == NULL)
2845 return -ENOMEM;
2846 return gsm_control_wait(dlci->gsm, ctrl);
2847}
2848
2849static int gsm_carrier_raised(struct tty_port *port)
2850{
2851 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2852 /* Not yet open so no carrier info */
2853 if (dlci->state != DLCI_OPEN)
2854 return 0;
2855 if (debug & 2)
2856 return 1;
2857 return dlci->modem_rx & TIOCM_CD;
2858}
2859
2860static void gsm_dtr_rts(struct tty_port *port, int onoff)
2861{
2862 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2863 unsigned int modem_tx = dlci->modem_tx;
2864 if (onoff)
2865 modem_tx |= TIOCM_DTR | TIOCM_RTS;
2866 else
2867 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
2868 if (modem_tx != dlci->modem_tx) {
2869 dlci->modem_tx = modem_tx;
2870 gsmtty_modem_update(dlci, 0);
2871 }
2872}
2873
2874static const struct tty_port_operations gsm_port_ops = {
2875 .carrier_raised = gsm_carrier_raised,
2876 .dtr_rts = gsm_dtr_rts,
2877};
2878
Jiri Slaby86176ed2012-08-07 21:47:28 +02002879static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty)
Alan Coxe1eaea42010-03-26 11:32:54 +00002880{
2881 struct gsm_mux *gsm;
2882 struct gsm_dlci *dlci;
Alan Coxe1eaea42010-03-26 11:32:54 +00002883 unsigned int line = tty->index;
2884 unsigned int mux = line >> 6;
Jiri Slaby86176ed2012-08-07 21:47:28 +02002885 bool alloc = false;
2886 int ret;
Alan Coxe1eaea42010-03-26 11:32:54 +00002887
2888 line = line & 0x3F;
2889
2890 if (mux >= MAX_MUX)
2891 return -ENXIO;
2892 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
2893 if (gsm_mux[mux] == NULL)
2894 return -EUNATCH;
2895 if (line == 0 || line > 61) /* 62/63 reserved */
2896 return -ECHRNG;
2897 gsm = gsm_mux[mux];
2898 if (gsm->dead)
2899 return -EL2HLT;
xiaojin7e8ac7b2012-08-13 13:43:15 +01002900 /* If DLCI 0 is not yet fully open return an error. This is ok from a locking
2901 perspective as we don't have to worry about this if DLCI0 is lost */
2902 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN)
2903 return -EL2NSYNC;
Alan Coxe1eaea42010-03-26 11:32:54 +00002904 dlci = gsm->dlci[line];
Jiri Slaby86176ed2012-08-07 21:47:28 +02002905 if (dlci == NULL) {
2906 alloc = true;
Alan Coxe1eaea42010-03-26 11:32:54 +00002907 dlci = gsm_dlci_alloc(gsm, line);
Jiri Slaby86176ed2012-08-07 21:47:28 +02002908 }
Alan Coxe1eaea42010-03-26 11:32:54 +00002909 if (dlci == NULL)
2910 return -ENOMEM;
Jiri Slaby86176ed2012-08-07 21:47:28 +02002911 ret = tty_port_install(&dlci->port, driver, tty);
2912 if (ret) {
2913 if (alloc)
2914 dlci_put(dlci);
2915 return ret;
2916 }
2917
Alan Coxe1eaea42010-03-26 11:32:54 +00002918 tty->driver_data = dlci;
Jiri Slaby86176ed2012-08-07 21:47:28 +02002919
2920 return 0;
2921}
2922
2923static int gsmtty_open(struct tty_struct *tty, struct file *filp)
2924{
2925 struct gsm_dlci *dlci = tty->driver_data;
2926 struct tty_port *port = &dlci->port;
2927
2928 port->count++;
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002929 dlci_get(dlci);
2930 dlci_get(dlci->gsm->dlci[0]);
2931 mux_get(dlci->gsm);
Alan Coxe1eaea42010-03-26 11:32:54 +00002932 tty_port_tty_set(port, tty);
2933
2934 dlci->modem_rx = 0;
2935 /* We could in theory open and close before we wait - eg if we get
2936 a DM straight back. This is ok as that will have caused a hangup */
2937 set_bit(ASYNCB_INITIALIZED, &port->flags);
2938 /* Start sending off SABM messages */
2939 gsm_dlci_begin_open(dlci);
2940 /* And wait for virtual carrier */
2941 return tty_port_block_til_ready(port, tty, filp);
2942}
2943
2944static void gsmtty_close(struct tty_struct *tty, struct file *filp)
2945{
2946 struct gsm_dlci *dlci = tty->driver_data;
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002947 struct gsm_mux *gsm;
2948
Alan Coxe1eaea42010-03-26 11:32:54 +00002949 if (dlci == NULL)
2950 return;
Russ Gorbybcd5abe2011-06-16 14:20:12 -07002951 mutex_lock(&dlci->mutex);
2952 gsm_destroy_network(dlci);
2953 mutex_unlock(&dlci->mutex);
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002954 gsm = dlci->gsm;
Alan Coxe1eaea42010-03-26 11:32:54 +00002955 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002956 goto out;
Alan Coxe1eaea42010-03-26 11:32:54 +00002957 gsm_dlci_begin_close(dlci);
2958 tty_port_close_end(&dlci->port, tty);
2959 tty_port_tty_set(&dlci->port, NULL);
Russ Gorby6ab8fba2011-06-16 14:20:13 -07002960out:
2961 dlci_put(dlci);
2962 dlci_put(gsm->dlci[0]);
2963 mux_put(gsm);
Alan Coxe1eaea42010-03-26 11:32:54 +00002964}
2965
2966static void gsmtty_hangup(struct tty_struct *tty)
2967{
2968 struct gsm_dlci *dlci = tty->driver_data;
2969 tty_port_hangup(&dlci->port);
2970 gsm_dlci_begin_close(dlci);
2971}
2972
2973static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf,
2974 int len)
2975{
2976 struct gsm_dlci *dlci = tty->driver_data;
2977 /* Stuff the bytes into the fifo queue */
2978 int sent = kfifo_in_locked(dlci->fifo, buf, len, &dlci->lock);
2979 /* Need to kick the channel */
2980 gsm_dlci_data_kick(dlci);
2981 return sent;
2982}
2983
2984static int gsmtty_write_room(struct tty_struct *tty)
2985{
2986 struct gsm_dlci *dlci = tty->driver_data;
2987 return TX_SIZE - kfifo_len(dlci->fifo);
2988}
2989
2990static int gsmtty_chars_in_buffer(struct tty_struct *tty)
2991{
2992 struct gsm_dlci *dlci = tty->driver_data;
2993 return kfifo_len(dlci->fifo);
2994}
2995
2996static void gsmtty_flush_buffer(struct tty_struct *tty)
2997{
2998 struct gsm_dlci *dlci = tty->driver_data;
2999 /* Caution needed: If we implement reliable transport classes
3000 then the data being transmitted can't simply be junked once
3001 it has first hit the stack. Until then we can just blow it
3002 away */
3003 kfifo_reset(dlci->fifo);
3004 /* Need to unhook this DLCI from the transmit queue logic */
3005}
3006
3007static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
3008{
3009 /* The FIFO handles the queue so the kernel will do the right
3010 thing waiting on chars_in_buffer before calling us. No work
3011 to do here */
3012}
3013
Alan Cox60b33c12011-02-14 16:26:14 +00003014static int gsmtty_tiocmget(struct tty_struct *tty)
Alan Coxe1eaea42010-03-26 11:32:54 +00003015{
3016 struct gsm_dlci *dlci = tty->driver_data;
3017 return dlci->modem_rx;
3018}
3019
Alan Cox20b9d172011-02-14 16:26:50 +00003020static int gsmtty_tiocmset(struct tty_struct *tty,
Alan Coxe1eaea42010-03-26 11:32:54 +00003021 unsigned int set, unsigned int clear)
3022{
3023 struct gsm_dlci *dlci = tty->driver_data;
3024 unsigned int modem_tx = dlci->modem_tx;
3025
Nikola Diklic-Perincf168072011-09-23 10:59:43 +02003026 modem_tx &= ~clear;
Alan Coxe1eaea42010-03-26 11:32:54 +00003027 modem_tx |= set;
3028
3029 if (modem_tx != dlci->modem_tx) {
3030 dlci->modem_tx = modem_tx;
3031 return gsmtty_modem_update(dlci, 0);
3032 }
3033 return 0;
3034}
3035
3036
Alan Cox6caa76b2011-02-14 16:27:22 +00003037static int gsmtty_ioctl(struct tty_struct *tty,
Alan Coxe1eaea42010-03-26 11:32:54 +00003038 unsigned int cmd, unsigned long arg)
3039{
Russ Gorbybcd5abe2011-06-16 14:20:12 -07003040 struct gsm_dlci *dlci = tty->driver_data;
3041 struct gsm_netconfig nc;
3042 int index;
3043
3044 switch (cmd) {
3045 case GSMIOC_ENABLE_NET:
3046 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc)))
3047 return -EFAULT;
3048 nc.if_name[IFNAMSIZ-1] = '\0';
3049 /* return net interface index or error code */
3050 mutex_lock(&dlci->mutex);
3051 index = gsm_create_network(dlci, &nc);
3052 mutex_unlock(&dlci->mutex);
3053 if (copy_to_user((void __user *)arg, &nc, sizeof(nc)))
3054 return -EFAULT;
3055 return index;
3056 case GSMIOC_DISABLE_NET:
3057 if (!capable(CAP_NET_ADMIN))
3058 return -EPERM;
3059 mutex_lock(&dlci->mutex);
3060 gsm_destroy_network(dlci);
3061 mutex_unlock(&dlci->mutex);
3062 return 0;
3063 default:
3064 return -ENOIOCTLCMD;
3065 }
Alan Coxe1eaea42010-03-26 11:32:54 +00003066}
3067
3068static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old)
3069{
3070 /* For the moment its fixed. In actual fact the speed information
3071 for the virtual channel can be propogated in both directions by
3072 the RPN control message. This however rapidly gets nasty as we
3073 then have to remap modem signals each way according to whether
3074 our virtual cable is null modem etc .. */
Alan Coxadc8d742012-07-14 15:31:47 +01003075 tty_termios_copy_hw(&tty->termios, old);
Alan Coxe1eaea42010-03-26 11:32:54 +00003076}
3077
3078static void gsmtty_throttle(struct tty_struct *tty)
3079{
3080 struct gsm_dlci *dlci = tty->driver_data;
Alan Coxadc8d742012-07-14 15:31:47 +01003081 if (tty->termios.c_cflag & CRTSCTS)
Alan Coxe1eaea42010-03-26 11:32:54 +00003082 dlci->modem_tx &= ~TIOCM_DTR;
3083 dlci->throttled = 1;
3084 /* Send an MSC with DTR cleared */
3085 gsmtty_modem_update(dlci, 0);
3086}
3087
3088static void gsmtty_unthrottle(struct tty_struct *tty)
3089{
3090 struct gsm_dlci *dlci = tty->driver_data;
Alan Coxadc8d742012-07-14 15:31:47 +01003091 if (tty->termios.c_cflag & CRTSCTS)
Alan Coxe1eaea42010-03-26 11:32:54 +00003092 dlci->modem_tx |= TIOCM_DTR;
3093 dlci->throttled = 0;
3094 /* Send an MSC with DTR set */
3095 gsmtty_modem_update(dlci, 0);
3096}
3097
3098static int gsmtty_break_ctl(struct tty_struct *tty, int state)
3099{
3100 struct gsm_dlci *dlci = tty->driver_data;
3101 int encode = 0; /* Off */
3102
3103 if (state == -1) /* "On indefinitely" - we can't encode this
3104 properly */
3105 encode = 0x0F;
3106 else if (state > 0) {
3107 encode = state / 200; /* mS to encoding */
3108 if (encode > 0x0F)
3109 encode = 0x0F; /* Best effort */
3110 }
3111 return gsmtty_modem_update(dlci, encode);
3112}
3113
Alan Coxe1eaea42010-03-26 11:32:54 +00003114
3115/* Virtual ttys for the demux */
3116static const struct tty_operations gsmtty_ops = {
Jiri Slaby86176ed2012-08-07 21:47:28 +02003117 .install = gsmtty_install,
Alan Coxe1eaea42010-03-26 11:32:54 +00003118 .open = gsmtty_open,
3119 .close = gsmtty_close,
3120 .write = gsmtty_write,
3121 .write_room = gsmtty_write_room,
3122 .chars_in_buffer = gsmtty_chars_in_buffer,
3123 .flush_buffer = gsmtty_flush_buffer,
3124 .ioctl = gsmtty_ioctl,
3125 .throttle = gsmtty_throttle,
3126 .unthrottle = gsmtty_unthrottle,
3127 .set_termios = gsmtty_set_termios,
3128 .hangup = gsmtty_hangup,
3129 .wait_until_sent = gsmtty_wait_until_sent,
3130 .tiocmget = gsmtty_tiocmget,
3131 .tiocmset = gsmtty_tiocmset,
3132 .break_ctl = gsmtty_break_ctl,
3133};
3134
3135
3136
3137static int __init gsm_init(void)
3138{
3139 /* Fill in our line protocol discipline, and register it */
3140 int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet);
3141 if (status != 0) {
Alan Cox5f9a31d2010-11-04 15:17:27 +00003142 pr_err("n_gsm: can't register line discipline (err = %d)\n",
3143 status);
Alan Coxe1eaea42010-03-26 11:32:54 +00003144 return status;
3145 }
3146
3147 gsm_tty_driver = alloc_tty_driver(256);
3148 if (!gsm_tty_driver) {
3149 tty_unregister_ldisc(N_GSM0710);
Alan Cox5f9a31d2010-11-04 15:17:27 +00003150 pr_err("gsm_init: tty allocation failed.\n");
Alan Coxe1eaea42010-03-26 11:32:54 +00003151 return -EINVAL;
3152 }
Alan Coxe1eaea42010-03-26 11:32:54 +00003153 gsm_tty_driver->driver_name = "gsmtty";
3154 gsm_tty_driver->name = "gsmtty";
3155 gsm_tty_driver->major = 0; /* Dynamic */
3156 gsm_tty_driver->minor_start = 0;
3157 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
3158 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
3159 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV
Alan Cox5f9a31d2010-11-04 15:17:27 +00003160 | TTY_DRIVER_HARDWARE_BREAK;
Alan Coxe1eaea42010-03-26 11:32:54 +00003161 gsm_tty_driver->init_termios = tty_std_termios;
3162 /* Fixme */
3163 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
3164 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
3165
3166 spin_lock_init(&gsm_mux_lock);
3167
3168 if (tty_register_driver(gsm_tty_driver)) {
3169 put_tty_driver(gsm_tty_driver);
3170 tty_unregister_ldisc(N_GSM0710);
Alan Cox5f9a31d2010-11-04 15:17:27 +00003171 pr_err("gsm_init: tty registration failed.\n");
Alan Coxe1eaea42010-03-26 11:32:54 +00003172 return -EBUSY;
3173 }
Alan Cox5f9a31d2010-11-04 15:17:27 +00003174 pr_debug("gsm_init: loaded as %d,%d.\n",
3175 gsm_tty_driver->major, gsm_tty_driver->minor_start);
Alan Coxe1eaea42010-03-26 11:32:54 +00003176 return 0;
3177}
3178
3179static void __exit gsm_exit(void)
3180{
3181 int status = tty_unregister_ldisc(N_GSM0710);
3182 if (status != 0)
Alan Cox5f9a31d2010-11-04 15:17:27 +00003183 pr_err("n_gsm: can't unregister line discipline (err = %d)\n",
3184 status);
Alan Coxe1eaea42010-03-26 11:32:54 +00003185 tty_unregister_driver(gsm_tty_driver);
3186 put_tty_driver(gsm_tty_driver);
Alan Coxe1eaea42010-03-26 11:32:54 +00003187}
3188
3189module_init(gsm_init);
3190module_exit(gsm_exit);
3191
3192
3193MODULE_LICENSE("GPL");
3194MODULE_ALIAS_LDISC(N_GSM0710);