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e1eaea46 AC |
1 | /* |
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 | |
22 | * Partly done: hooks so you can pull off frames to non tty devs | |
23 | * Restart DLCI 0 when it closes ? | |
24 | * Test basic encoding | |
25 | * Improve the tx engine | |
26 | * Resolve tx side locking by adding a queue_head and routing | |
27 | * all control traffic via it | |
28 | * General tidy/document | |
29 | * Review the locking/move to refcounts more (mux now moved to an | |
30 | * alloc/free model ready) | |
31 | * Use newest tty open/close port helpers and install hooks | |
32 | * What to do about power functions ? | |
33 | * Termios setting and negotiation | |
34 | * Do we need a 'which mux are you' ioctl to correlate mux and tty sets | |
35 | * | |
36 | */ | |
37 | ||
38 | #include <linux/types.h> | |
39 | #include <linux/major.h> | |
40 | #include <linux/errno.h> | |
41 | #include <linux/signal.h> | |
42 | #include <linux/fcntl.h> | |
43 | #include <linux/sched.h> | |
44 | #include <linux/interrupt.h> | |
45 | #include <linux/tty.h> | |
e1eaea46 AC |
46 | #include <linux/ctype.h> |
47 | #include <linux/mm.h> | |
48 | #include <linux/string.h> | |
49 | #include <linux/slab.h> | |
50 | #include <linux/poll.h> | |
51 | #include <linux/bitops.h> | |
52 | #include <linux/file.h> | |
53 | #include <linux/uaccess.h> | |
54 | #include <linux/module.h> | |
55 | #include <linux/timer.h> | |
56 | #include <linux/tty_flip.h> | |
57 | #include <linux/tty_driver.h> | |
58 | #include <linux/serial.h> | |
59 | #include <linux/kfifo.h> | |
60 | #include <linux/skbuff.h> | |
61 | #include <linux/gsmmux.h> | |
62 | ||
63 | static int debug; | |
64 | module_param(debug, int, 0600); | |
65 | ||
66 | #define T1 (HZ/10) | |
67 | #define T2 (HZ/3) | |
68 | #define N2 3 | |
69 | ||
70 | /* Use long timers for testing at low speed with debug on */ | |
71 | #ifdef DEBUG_TIMING | |
72 | #define T1 HZ | |
73 | #define T2 (2 * HZ) | |
74 | #endif | |
75 | ||
76 | /* Semi-arbitary buffer size limits. 0710 is normally run with 32-64 byte | |
77 | limits so this is plenty */ | |
78 | #define MAX_MRU 512 | |
79 | #define MAX_MTU 512 | |
80 | ||
81 | /* | |
82 | * Each block of data we have queued to go out is in the form of | |
83 | * a gsm_msg which holds everything we need in a link layer independant | |
84 | * format | |
85 | */ | |
86 | ||
87 | struct gsm_msg { | |
88 | struct gsm_msg *next; | |
89 | u8 addr; /* DLCI address + flags */ | |
90 | u8 ctrl; /* Control byte + flags */ | |
91 | unsigned int len; /* Length of data block (can be zero) */ | |
92 | unsigned char *data; /* Points into buffer but not at the start */ | |
93 | unsigned char buffer[0]; | |
94 | }; | |
95 | ||
96 | /* | |
97 | * Each active data link has a gsm_dlci structure associated which ties | |
98 | * the link layer to an optional tty (if the tty side is open). To avoid | |
99 | * complexity right now these are only ever freed up when the mux is | |
100 | * shut down. | |
101 | * | |
102 | * At the moment we don't free DLCI objects until the mux is torn down | |
103 | * this avoid object life time issues but might be worth review later. | |
104 | */ | |
105 | ||
106 | struct gsm_dlci { | |
107 | struct gsm_mux *gsm; | |
108 | int addr; | |
109 | int state; | |
110 | #define DLCI_CLOSED 0 | |
111 | #define DLCI_OPENING 1 /* Sending SABM not seen UA */ | |
112 | #define DLCI_OPEN 2 /* SABM/UA complete */ | |
113 | #define DLCI_CLOSING 3 /* Sending DISC not seen UA/DM */ | |
114 | ||
115 | /* Link layer */ | |
116 | spinlock_t lock; /* Protects the internal state */ | |
117 | struct timer_list t1; /* Retransmit timer for SABM and UA */ | |
118 | int retries; | |
119 | /* Uplink tty if active */ | |
120 | struct tty_port port; /* The tty bound to this DLCI if there is one */ | |
121 | struct kfifo *fifo; /* Queue fifo for the DLCI */ | |
122 | struct kfifo _fifo; /* For new fifo API porting only */ | |
123 | int adaption; /* Adaption layer in use */ | |
124 | u32 modem_rx; /* Our incoming virtual modem lines */ | |
125 | u32 modem_tx; /* Our outgoing modem lines */ | |
126 | int dead; /* Refuse re-open */ | |
127 | /* Flow control */ | |
128 | int throttled; /* Private copy of throttle state */ | |
129 | int constipated; /* Throttle status for outgoing */ | |
130 | /* Packetised I/O */ | |
131 | struct sk_buff *skb; /* Frame being sent */ | |
132 | struct sk_buff_head skb_list; /* Queued frames */ | |
133 | /* Data handling callback */ | |
134 | void (*data)(struct gsm_dlci *dlci, u8 *data, int len); | |
135 | }; | |
136 | ||
137 | /* DLCI 0, 62/63 are special or reseved see gsmtty_open */ | |
138 | ||
139 | #define NUM_DLCI 64 | |
140 | ||
141 | /* | |
142 | * DLCI 0 is used to pass control blocks out of band of the data | |
143 | * flow (and with a higher link priority). One command can be outstanding | |
144 | * at a time and we use this structure to manage them. They are created | |
145 | * and destroyed by the user context, and updated by the receive paths | |
146 | * and timers | |
147 | */ | |
148 | ||
149 | struct gsm_control { | |
150 | u8 cmd; /* Command we are issuing */ | |
151 | u8 *data; /* Data for the command in case we retransmit */ | |
152 | int len; /* Length of block for retransmission */ | |
153 | int done; /* Done flag */ | |
154 | int error; /* Error if any */ | |
155 | }; | |
156 | ||
157 | /* | |
158 | * Each GSM mux we have is represented by this structure. If we are | |
159 | * operating as an ldisc then we use this structure as our ldisc | |
160 | * state. We need to sort out lifetimes and locking with respect | |
161 | * to the gsm mux array. For now we don't free DLCI objects that | |
162 | * have been instantiated until the mux itself is terminated. | |
163 | * | |
164 | * To consider further: tty open versus mux shutdown. | |
165 | */ | |
166 | ||
167 | struct gsm_mux { | |
168 | struct tty_struct *tty; /* The tty our ldisc is bound to */ | |
169 | spinlock_t lock; | |
170 | ||
171 | /* Events on the GSM channel */ | |
172 | wait_queue_head_t event; | |
173 | ||
174 | /* Bits for GSM mode decoding */ | |
175 | ||
176 | /* Framing Layer */ | |
177 | unsigned char *buf; | |
178 | int state; | |
179 | #define GSM_SEARCH 0 | |
180 | #define GSM_START 1 | |
181 | #define GSM_ADDRESS 2 | |
182 | #define GSM_CONTROL 3 | |
183 | #define GSM_LEN 4 | |
184 | #define GSM_DATA 5 | |
185 | #define GSM_FCS 6 | |
186 | #define GSM_OVERRUN 7 | |
187 | unsigned int len; | |
188 | unsigned int address; | |
189 | unsigned int count; | |
190 | int escape; | |
191 | int encoding; | |
192 | u8 control; | |
193 | u8 fcs; | |
194 | u8 *txframe; /* TX framing buffer */ | |
195 | ||
196 | /* Methods for the receiver side */ | |
197 | void (*receive)(struct gsm_mux *gsm, u8 ch); | |
198 | void (*error)(struct gsm_mux *gsm, u8 ch, u8 flag); | |
199 | /* And transmit side */ | |
200 | int (*output)(struct gsm_mux *mux, u8 *data, int len); | |
201 | ||
202 | /* Link Layer */ | |
203 | unsigned int mru; | |
204 | unsigned int mtu; | |
205 | int initiator; /* Did we initiate connection */ | |
206 | int dead; /* Has the mux been shut down */ | |
207 | struct gsm_dlci *dlci[NUM_DLCI]; | |
208 | int constipated; /* Asked by remote to shut up */ | |
209 | ||
210 | spinlock_t tx_lock; | |
211 | unsigned int tx_bytes; /* TX data outstanding */ | |
212 | #define TX_THRESH_HI 8192 | |
213 | #define TX_THRESH_LO 2048 | |
214 | struct gsm_msg *tx_head; /* Pending data packets */ | |
215 | struct gsm_msg *tx_tail; | |
216 | ||
217 | /* Control messages */ | |
218 | struct timer_list t2_timer; /* Retransmit timer for commands */ | |
219 | int cretries; /* Command retry counter */ | |
220 | struct gsm_control *pending_cmd;/* Our current pending command */ | |
221 | spinlock_t control_lock; /* Protects the pending command */ | |
222 | ||
223 | /* Configuration */ | |
224 | int adaption; /* 1 or 2 supported */ | |
225 | u8 ftype; /* UI or UIH */ | |
226 | int t1, t2; /* Timers in 1/100th of a sec */ | |
227 | int n2; /* Retry count */ | |
228 | ||
229 | /* Statistics (not currently exposed) */ | |
230 | unsigned long bad_fcs; | |
231 | unsigned long malformed; | |
232 | unsigned long io_error; | |
233 | unsigned long bad_size; | |
234 | unsigned long unsupported; | |
235 | }; | |
236 | ||
237 | ||
238 | /* | |
239 | * Mux objects - needed so that we can translate a tty index into the | |
240 | * relevant mux and DLCI. | |
241 | */ | |
242 | ||
243 | #define MAX_MUX 4 /* 256 minors */ | |
244 | static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */ | |
245 | static spinlock_t gsm_mux_lock; | |
246 | ||
247 | /* | |
248 | * This section of the driver logic implements the GSM encodings | |
249 | * both the basic and the 'advanced'. Reliable transport is not | |
250 | * supported. | |
251 | */ | |
252 | ||
253 | #define CR 0x02 | |
254 | #define EA 0x01 | |
255 | #define PF 0x10 | |
256 | ||
257 | /* I is special: the rest are ..*/ | |
258 | #define RR 0x01 | |
259 | #define UI 0x03 | |
260 | #define RNR 0x05 | |
261 | #define REJ 0x09 | |
262 | #define DM 0x0F | |
263 | #define SABM 0x2F | |
264 | #define DISC 0x43 | |
265 | #define UA 0x63 | |
266 | #define UIH 0xEF | |
267 | ||
268 | /* Channel commands */ | |
269 | #define CMD_NSC 0x09 | |
270 | #define CMD_TEST 0x11 | |
271 | #define CMD_PSC 0x21 | |
272 | #define CMD_RLS 0x29 | |
273 | #define CMD_FCOFF 0x31 | |
274 | #define CMD_PN 0x41 | |
275 | #define CMD_RPN 0x49 | |
276 | #define CMD_FCON 0x51 | |
277 | #define CMD_CLD 0x61 | |
278 | #define CMD_SNC 0x69 | |
279 | #define CMD_MSC 0x71 | |
280 | ||
281 | /* Virtual modem bits */ | |
282 | #define MDM_FC 0x01 | |
283 | #define MDM_RTC 0x02 | |
284 | #define MDM_RTR 0x04 | |
285 | #define MDM_IC 0x20 | |
286 | #define MDM_DV 0x40 | |
287 | ||
288 | #define GSM0_SOF 0xF9 | |
289 | #define GSM1_SOF 0x7E | |
290 | #define GSM1_ESCAPE 0x7D | |
291 | #define GSM1_ESCAPE_BITS 0x20 | |
292 | #define XON 0x11 | |
293 | #define XOFF 0x13 | |
294 | ||
295 | static const struct tty_port_operations gsm_port_ops; | |
296 | ||
297 | /* | |
298 | * CRC table for GSM 0710 | |
299 | */ | |
300 | ||
301 | static const u8 gsm_fcs8[256] = { | |
302 | 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75, | |
303 | 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B, | |
304 | 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69, | |
305 | 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67, | |
306 | 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D, | |
307 | 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43, | |
308 | 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51, | |
309 | 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F, | |
310 | 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05, | |
311 | 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B, | |
312 | 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19, | |
313 | 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17, | |
314 | 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D, | |
315 | 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33, | |
316 | 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21, | |
317 | 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F, | |
318 | 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95, | |
319 | 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B, | |
320 | 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89, | |
321 | 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87, | |
322 | 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD, | |
323 | 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3, | |
324 | 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1, | |
325 | 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF, | |
326 | 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5, | |
327 | 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB, | |
328 | 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9, | |
329 | 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7, | |
330 | 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD, | |
331 | 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3, | |
332 | 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1, | |
333 | 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF | |
334 | }; | |
335 | ||
336 | #define INIT_FCS 0xFF | |
337 | #define GOOD_FCS 0xCF | |
338 | ||
339 | /** | |
340 | * gsm_fcs_add - update FCS | |
341 | * @fcs: Current FCS | |
342 | * @c: Next data | |
343 | * | |
344 | * Update the FCS to include c. Uses the algorithm in the specification | |
345 | * notes. | |
346 | */ | |
347 | ||
348 | static inline u8 gsm_fcs_add(u8 fcs, u8 c) | |
349 | { | |
350 | return gsm_fcs8[fcs ^ c]; | |
351 | } | |
352 | ||
353 | /** | |
354 | * gsm_fcs_add_block - update FCS for a block | |
355 | * @fcs: Current FCS | |
356 | * @c: buffer of data | |
357 | * @len: length of buffer | |
358 | * | |
359 | * Update the FCS to include c. Uses the algorithm in the specification | |
360 | * notes. | |
361 | */ | |
362 | ||
363 | static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len) | |
364 | { | |
365 | while (len--) | |
366 | fcs = gsm_fcs8[fcs ^ *c++]; | |
367 | return fcs; | |
368 | } | |
369 | ||
370 | /** | |
371 | * gsm_read_ea - read a byte into an EA | |
372 | * @val: variable holding value | |
373 | * c: byte going into the EA | |
374 | * | |
375 | * Processes one byte of an EA. Updates the passed variable | |
376 | * and returns 1 if the EA is now completely read | |
377 | */ | |
378 | ||
379 | static int gsm_read_ea(unsigned int *val, u8 c) | |
380 | { | |
381 | /* Add the next 7 bits into the value */ | |
382 | *val <<= 7; | |
383 | *val |= c >> 1; | |
384 | /* Was this the last byte of the EA 1 = yes*/ | |
385 | return c & EA; | |
386 | } | |
387 | ||
388 | /** | |
389 | * gsm_encode_modem - encode modem data bits | |
390 | * @dlci: DLCI to encode from | |
391 | * | |
392 | * Returns the correct GSM encoded modem status bits (6 bit field) for | |
393 | * the current status of the DLCI and attached tty object | |
394 | */ | |
395 | ||
396 | static u8 gsm_encode_modem(const struct gsm_dlci *dlci) | |
397 | { | |
398 | u8 modembits = 0; | |
399 | /* FC is true flow control not modem bits */ | |
400 | if (dlci->throttled) | |
401 | modembits |= MDM_FC; | |
402 | if (dlci->modem_tx & TIOCM_DTR) | |
403 | modembits |= MDM_RTC; | |
404 | if (dlci->modem_tx & TIOCM_RTS) | |
405 | modembits |= MDM_RTR; | |
406 | if (dlci->modem_tx & TIOCM_RI) | |
407 | modembits |= MDM_IC; | |
408 | if (dlci->modem_tx & TIOCM_CD) | |
409 | modembits |= MDM_DV; | |
410 | return modembits; | |
411 | } | |
412 | ||
413 | /** | |
414 | * gsm_print_packet - display a frame for debug | |
415 | * @hdr: header to print before decode | |
416 | * @addr: address EA from the frame | |
417 | * @cr: C/R bit from the frame | |
418 | * @control: control including PF bit | |
419 | * @data: following data bytes | |
420 | * @dlen: length of data | |
421 | * | |
422 | * Displays a packet in human readable format for debugging purposes. The | |
423 | * style is based on amateur radio LAP-B dump display. | |
424 | */ | |
425 | ||
426 | static void gsm_print_packet(const char *hdr, int addr, int cr, | |
427 | u8 control, const u8 *data, int dlen) | |
428 | { | |
429 | if (!(debug & 1)) | |
430 | return; | |
431 | ||
432 | printk(KERN_INFO "%s %d) %c: ", hdr, addr, "RC"[cr]); | |
433 | ||
434 | switch (control & ~PF) { | |
435 | case SABM: | |
436 | printk(KERN_CONT "SABM"); | |
437 | break; | |
438 | case UA: | |
439 | printk(KERN_CONT "UA"); | |
440 | break; | |
441 | case DISC: | |
442 | printk(KERN_CONT "DISC"); | |
443 | break; | |
444 | case DM: | |
445 | printk(KERN_CONT "DM"); | |
446 | break; | |
447 | case UI: | |
448 | printk(KERN_CONT "UI"); | |
449 | break; | |
450 | case UIH: | |
451 | printk(KERN_CONT "UIH"); | |
452 | break; | |
453 | default: | |
454 | if (!(control & 0x01)) { | |
455 | printk(KERN_CONT "I N(S)%d N(R)%d", | |
456 | (control & 0x0E) >> 1, (control & 0xE)>> 5); | |
457 | } else switch (control & 0x0F) { | |
458 | case RR: | |
459 | printk("RR(%d)", (control & 0xE0) >> 5); | |
460 | break; | |
461 | case RNR: | |
462 | printk("RNR(%d)", (control & 0xE0) >> 5); | |
463 | break; | |
464 | case REJ: | |
465 | printk("REJ(%d)", (control & 0xE0) >> 5); | |
466 | break; | |
467 | default: | |
468 | printk(KERN_CONT "[%02X]", control); | |
469 | } | |
470 | } | |
471 | ||
472 | if (control & PF) | |
473 | printk(KERN_CONT "(P)"); | |
474 | else | |
475 | printk(KERN_CONT "(F)"); | |
476 | ||
477 | if (dlen) { | |
478 | int ct = 0; | |
479 | while (dlen--) { | |
480 | if (ct % 8 == 0) | |
481 | printk(KERN_CONT "\n "); | |
482 | printk(KERN_CONT "%02X ", *data++); | |
483 | ct++; | |
484 | } | |
485 | } | |
486 | printk(KERN_CONT "\n"); | |
487 | } | |
488 | ||
489 | ||
490 | /* | |
491 | * Link level transmission side | |
492 | */ | |
493 | ||
494 | /** | |
495 | * gsm_stuff_packet - bytestuff a packet | |
496 | * @ibuf: input | |
497 | * @obuf: output | |
498 | * @len: length of input | |
499 | * | |
500 | * Expand a buffer by bytestuffing it. The worst case size change | |
501 | * is doubling and the caller is responsible for handing out | |
502 | * suitable sized buffers. | |
503 | */ | |
504 | ||
505 | static int gsm_stuff_frame(const u8 *input, u8 *output, int len) | |
506 | { | |
507 | int olen = 0; | |
508 | while (len--) { | |
509 | if (*input == GSM1_SOF || *input == GSM1_ESCAPE | |
510 | || *input == XON || *input == XOFF) { | |
511 | *output++ = GSM1_ESCAPE; | |
512 | *output++ = *input++ ^ GSM1_ESCAPE_BITS; | |
513 | olen++; | |
514 | } else | |
515 | *output++ = *input++; | |
516 | olen++; | |
517 | } | |
518 | return olen; | |
519 | } | |
520 | ||
521 | static void hex_packet(const unsigned char *p, int len) | |
522 | { | |
523 | int i; | |
524 | for (i = 0; i < len; i++) { | |
525 | if (i && (i % 16) == 0) | |
526 | printk("\n"); | |
527 | printk("%02X ", *p++); | |
528 | } | |
529 | printk("\n"); | |
530 | } | |
531 | ||
532 | /** | |
533 | * gsm_send - send a control frame | |
534 | * @gsm: our GSM mux | |
535 | * @addr: address for control frame | |
536 | * @cr: command/response bit | |
537 | * @control: control byte including PF bit | |
538 | * | |
539 | * Format up and transmit a control frame. These do not go via the | |
540 | * queueing logic as they should be transmitted ahead of data when | |
541 | * they are needed. | |
542 | * | |
543 | * FIXME: Lock versus data TX path | |
544 | */ | |
545 | ||
546 | static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control) | |
547 | { | |
548 | int len; | |
549 | u8 cbuf[10]; | |
550 | u8 ibuf[3]; | |
551 | ||
552 | switch (gsm->encoding) { | |
553 | case 0: | |
554 | cbuf[0] = GSM0_SOF; | |
555 | cbuf[1] = (addr << 2) | (cr << 1) | EA; | |
556 | cbuf[2] = control; | |
557 | cbuf[3] = EA; /* Length of data = 0 */ | |
558 | cbuf[4] = 0xFF - gsm_fcs_add_block(INIT_FCS, cbuf + 1, 3); | |
559 | cbuf[5] = GSM0_SOF; | |
560 | len = 6; | |
561 | break; | |
562 | case 1: | |
563 | case 2: | |
564 | /* Control frame + packing (but not frame stuffing) in mode 1 */ | |
565 | ibuf[0] = (addr << 2) | (cr << 1) | EA; | |
566 | ibuf[1] = control; | |
567 | ibuf[2] = 0xFF - gsm_fcs_add_block(INIT_FCS, ibuf, 2); | |
568 | /* Stuffing may double the size worst case */ | |
569 | len = gsm_stuff_frame(ibuf, cbuf + 1, 3); | |
570 | /* Now add the SOF markers */ | |
571 | cbuf[0] = GSM1_SOF; | |
572 | cbuf[len + 1] = GSM1_SOF; | |
573 | /* FIXME: we can omit the lead one in many cases */ | |
574 | len += 2; | |
575 | break; | |
576 | default: | |
577 | WARN_ON(1); | |
578 | return; | |
579 | } | |
580 | gsm->output(gsm, cbuf, len); | |
581 | gsm_print_packet("-->", addr, cr, control, NULL, 0); | |
582 | } | |
583 | ||
584 | /** | |
585 | * gsm_response - send a control response | |
586 | * @gsm: our GSM mux | |
587 | * @addr: address for control frame | |
588 | * @control: control byte including PF bit | |
589 | * | |
590 | * Format up and transmit a link level response frame. | |
591 | */ | |
592 | ||
593 | static inline void gsm_response(struct gsm_mux *gsm, int addr, int control) | |
594 | { | |
595 | gsm_send(gsm, addr, 0, control); | |
596 | } | |
597 | ||
598 | /** | |
599 | * gsm_command - send a control command | |
600 | * @gsm: our GSM mux | |
601 | * @addr: address for control frame | |
602 | * @control: control byte including PF bit | |
603 | * | |
604 | * Format up and transmit a link level command frame. | |
605 | */ | |
606 | ||
607 | static inline void gsm_command(struct gsm_mux *gsm, int addr, int control) | |
608 | { | |
609 | gsm_send(gsm, addr, 1, control); | |
610 | } | |
611 | ||
612 | /* Data transmission */ | |
613 | ||
614 | #define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */ | |
615 | ||
616 | /** | |
617 | * gsm_data_alloc - allocate data frame | |
618 | * @gsm: GSM mux | |
619 | * @addr: DLCI address | |
620 | * @len: length excluding header and FCS | |
621 | * @ctrl: control byte | |
622 | * | |
623 | * Allocate a new data buffer for sending frames with data. Space is left | |
624 | * at the front for header bytes but that is treated as an implementation | |
625 | * detail and not for the high level code to use | |
626 | */ | |
627 | ||
628 | static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len, | |
629 | u8 ctrl) | |
630 | { | |
631 | struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN, | |
632 | GFP_ATOMIC); | |
633 | if (m == NULL) | |
634 | return NULL; | |
635 | m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */ | |
636 | m->len = len; | |
637 | m->addr = addr; | |
638 | m->ctrl = ctrl; | |
639 | m->next = NULL; | |
640 | return m; | |
641 | } | |
642 | ||
643 | /** | |
644 | * gsm_data_kick - poke the queue | |
645 | * @gsm: GSM Mux | |
646 | * | |
647 | * The tty device has called us to indicate that room has appeared in | |
648 | * the transmit queue. Ram more data into the pipe if we have any | |
649 | * | |
650 | * FIXME: lock against link layer control transmissions | |
651 | */ | |
652 | ||
653 | static void gsm_data_kick(struct gsm_mux *gsm) | |
654 | { | |
655 | struct gsm_msg *msg = gsm->tx_head; | |
656 | int len; | |
657 | int skip_sof = 0; | |
658 | ||
659 | /* FIXME: We need to apply this solely to data messages */ | |
660 | if (gsm->constipated) | |
661 | return; | |
662 | ||
663 | while (gsm->tx_head != NULL) { | |
664 | msg = gsm->tx_head; | |
665 | if (gsm->encoding != 0) { | |
666 | gsm->txframe[0] = GSM1_SOF; | |
667 | len = gsm_stuff_frame(msg->data, | |
668 | gsm->txframe + 1, msg->len); | |
669 | gsm->txframe[len + 1] = GSM1_SOF; | |
670 | len += 2; | |
671 | } else { | |
672 | gsm->txframe[0] = GSM0_SOF; | |
673 | memcpy(gsm->txframe + 1 , msg->data, msg->len); | |
674 | gsm->txframe[msg->len + 1] = GSM0_SOF; | |
675 | len = msg->len + 2; | |
676 | } | |
677 | ||
678 | if (debug & 4) { | |
679 | printk("gsm_data_kick: \n"); | |
680 | hex_packet(gsm->txframe, len); | |
681 | } | |
682 | ||
683 | if (gsm->output(gsm, gsm->txframe + skip_sof, | |
684 | len - skip_sof) < 0) | |
685 | break; | |
686 | /* FIXME: Can eliminate one SOF in many more cases */ | |
687 | gsm->tx_head = msg->next; | |
688 | if (gsm->tx_head == NULL) | |
689 | gsm->tx_tail = NULL; | |
690 | gsm->tx_bytes -= msg->len; | |
691 | kfree(msg); | |
692 | /* For a burst of frames skip the extra SOF within the | |
693 | burst */ | |
694 | skip_sof = 1; | |
695 | } | |
696 | } | |
697 | ||
698 | /** | |
699 | * __gsm_data_queue - queue a UI or UIH frame | |
700 | * @dlci: DLCI sending the data | |
701 | * @msg: message queued | |
702 | * | |
703 | * Add data to the transmit queue and try and get stuff moving | |
704 | * out of the mux tty if not already doing so. The Caller must hold | |
705 | * the gsm tx lock. | |
706 | */ | |
707 | ||
708 | static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg) | |
709 | { | |
710 | struct gsm_mux *gsm = dlci->gsm; | |
711 | u8 *dp = msg->data; | |
712 | u8 *fcs = dp + msg->len; | |
713 | ||
714 | /* Fill in the header */ | |
715 | if (gsm->encoding == 0) { | |
716 | if (msg->len < 128) | |
717 | *--dp = (msg->len << 1) | EA; | |
718 | else { | |
719 | *--dp = (msg->len >> 6) | EA; | |
720 | *--dp = (msg->len & 127) << 1; | |
721 | } | |
722 | } | |
723 | ||
724 | *--dp = msg->ctrl; | |
725 | if (gsm->initiator) | |
726 | *--dp = (msg->addr << 2) | 2 | EA; | |
727 | else | |
728 | *--dp = (msg->addr << 2) | EA; | |
729 | *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp); | |
730 | /* Ugly protocol layering violation */ | |
731 | if (msg->ctrl == UI || msg->ctrl == (UI|PF)) | |
732 | *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len); | |
733 | *fcs = 0xFF - *fcs; | |
734 | ||
735 | gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl, | |
736 | msg->data, msg->len); | |
737 | ||
738 | /* Move the header back and adjust the length, also allow for the FCS | |
739 | now tacked on the end */ | |
740 | msg->len += (msg->data - dp) + 1; | |
741 | msg->data = dp; | |
742 | ||
743 | /* Add to the actual output queue */ | |
744 | if (gsm->tx_tail) | |
745 | gsm->tx_tail->next = msg; | |
746 | else | |
747 | gsm->tx_head = msg; | |
748 | gsm->tx_tail = msg; | |
749 | gsm->tx_bytes += msg->len; | |
750 | gsm_data_kick(gsm); | |
751 | } | |
752 | ||
753 | /** | |
754 | * gsm_data_queue - queue a UI or UIH frame | |
755 | * @dlci: DLCI sending the data | |
756 | * @msg: message queued | |
757 | * | |
758 | * Add data to the transmit queue and try and get stuff moving | |
759 | * out of the mux tty if not already doing so. Take the | |
760 | * the gsm tx lock and dlci lock. | |
761 | */ | |
762 | ||
763 | static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg) | |
764 | { | |
765 | unsigned long flags; | |
766 | spin_lock_irqsave(&dlci->gsm->tx_lock, flags); | |
767 | __gsm_data_queue(dlci, msg); | |
768 | spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags); | |
769 | } | |
770 | ||
771 | /** | |
772 | * gsm_dlci_data_output - try and push data out of a DLCI | |
773 | * @gsm: mux | |
774 | * @dlci: the DLCI to pull data from | |
775 | * | |
776 | * Pull data from a DLCI and send it into the transmit queue if there | |
777 | * is data. Keep to the MRU of the mux. This path handles the usual tty | |
778 | * interface which is a byte stream with optional modem data. | |
779 | * | |
780 | * Caller must hold the tx_lock of the mux. | |
781 | */ | |
782 | ||
783 | static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci) | |
784 | { | |
785 | struct gsm_msg *msg; | |
786 | u8 *dp; | |
787 | int len, size; | |
788 | int h = dlci->adaption - 1; | |
789 | ||
790 | len = kfifo_len(dlci->fifo); | |
791 | if (len == 0) | |
792 | return 0; | |
793 | ||
794 | /* MTU/MRU count only the data bits */ | |
795 | if (len > gsm->mtu) | |
796 | len = gsm->mtu; | |
797 | ||
798 | size = len + h; | |
799 | ||
800 | msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype); | |
801 | /* FIXME: need a timer or something to kick this so it can't | |
802 | get stuck with no work outstanding and no buffer free */ | |
803 | if (msg == NULL) | |
804 | return -ENOMEM; | |
805 | dp = msg->data; | |
806 | switch (dlci->adaption) { | |
807 | case 1: /* Unstructured */ | |
808 | break; | |
809 | case 2: /* Unstructed with modem bits. Always one byte as we never | |
810 | send inline break data */ | |
811 | *dp += gsm_encode_modem(dlci); | |
812 | len--; | |
813 | break; | |
814 | } | |
815 | WARN_ON(kfifo_out_locked(dlci->fifo, dp , len, &dlci->lock) != len); | |
816 | __gsm_data_queue(dlci, msg); | |
817 | /* Bytes of data we used up */ | |
818 | return size; | |
819 | } | |
820 | ||
821 | /** | |
822 | * gsm_dlci_data_output_framed - try and push data out of a DLCI | |
823 | * @gsm: mux | |
824 | * @dlci: the DLCI to pull data from | |
825 | * | |
826 | * Pull data from a DLCI and send it into the transmit queue if there | |
827 | * is data. Keep to the MRU of the mux. This path handles framed data | |
828 | * queued as skbuffs to the DLCI. | |
829 | * | |
830 | * Caller must hold the tx_lock of the mux. | |
831 | */ | |
832 | ||
833 | static int gsm_dlci_data_output_framed(struct gsm_mux *gsm, | |
834 | struct gsm_dlci *dlci) | |
835 | { | |
836 | struct gsm_msg *msg; | |
837 | u8 *dp; | |
838 | int len, size; | |
839 | int last = 0, first = 0; | |
840 | int overhead = 0; | |
841 | ||
842 | /* One byte per frame is used for B/F flags */ | |
843 | if (dlci->adaption == 4) | |
844 | overhead = 1; | |
845 | ||
846 | /* dlci->skb is locked by tx_lock */ | |
847 | if (dlci->skb == NULL) { | |
848 | dlci->skb = skb_dequeue(&dlci->skb_list); | |
849 | if (dlci->skb == NULL) | |
850 | return 0; | |
851 | first = 1; | |
852 | } | |
853 | len = dlci->skb->len + overhead; | |
854 | ||
855 | /* MTU/MRU count only the data bits */ | |
856 | if (len > gsm->mtu) { | |
857 | if (dlci->adaption == 3) { | |
858 | /* Over long frame, bin it */ | |
859 | kfree_skb(dlci->skb); | |
860 | dlci->skb = NULL; | |
861 | return 0; | |
862 | } | |
863 | len = gsm->mtu; | |
864 | } else | |
865 | last = 1; | |
866 | ||
867 | size = len + overhead; | |
868 | msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype); | |
869 | ||
870 | /* FIXME: need a timer or something to kick this so it can't | |
871 | get stuck with no work outstanding and no buffer free */ | |
872 | if (msg == NULL) | |
873 | return -ENOMEM; | |
874 | dp = msg->data; | |
875 | ||
876 | if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */ | |
877 | /* Flag byte to carry the start/end info */ | |
878 | *dp++ = last << 7 | first << 6 | 1; /* EA */ | |
879 | len--; | |
880 | } | |
881 | memcpy(dp, skb_pull(dlci->skb, len), len); | |
882 | __gsm_data_queue(dlci, msg); | |
883 | if (last) | |
884 | dlci->skb = NULL; | |
885 | return size; | |
886 | } | |
887 | ||
888 | /** | |
889 | * gsm_dlci_data_sweep - look for data to send | |
890 | * @gsm: the GSM mux | |
891 | * | |
892 | * Sweep the GSM mux channels in priority order looking for ones with | |
893 | * data to send. We could do with optimising this scan a bit. We aim | |
894 | * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit | |
895 | * TX_THRESH_LO we get called again | |
896 | * | |
897 | * FIXME: We should round robin between groups and in theory you can | |
898 | * renegotiate DLCI priorities with optional stuff. Needs optimising. | |
899 | */ | |
900 | ||
901 | static void gsm_dlci_data_sweep(struct gsm_mux *gsm) | |
902 | { | |
903 | int len; | |
904 | /* Priority ordering: We should do priority with RR of the groups */ | |
905 | int i = 1; | |
e1eaea46 | 906 | |
e1eaea46 AC |
907 | while (i < NUM_DLCI) { |
908 | struct gsm_dlci *dlci; | |
909 | ||
910 | if (gsm->tx_bytes > TX_THRESH_HI) | |
911 | break; | |
912 | dlci = gsm->dlci[i]; | |
913 | if (dlci == NULL || dlci->constipated) { | |
914 | i++; | |
915 | continue; | |
916 | } | |
917 | if (dlci->adaption < 3) | |
918 | len = gsm_dlci_data_output(gsm, dlci); | |
919 | else | |
920 | len = gsm_dlci_data_output_framed(gsm, dlci); | |
921 | if (len < 0) | |
e73790a5 | 922 | break; |
e1eaea46 AC |
923 | /* DLCI empty - try the next */ |
924 | if (len == 0) | |
925 | i++; | |
926 | } | |
e1eaea46 AC |
927 | } |
928 | ||
929 | /** | |
930 | * gsm_dlci_data_kick - transmit if possible | |
931 | * @dlci: DLCI to kick | |
932 | * | |
933 | * Transmit data from this DLCI if the queue is empty. We can't rely on | |
934 | * a tty wakeup except when we filled the pipe so we need to fire off | |
935 | * new data ourselves in other cases. | |
936 | */ | |
937 | ||
938 | static void gsm_dlci_data_kick(struct gsm_dlci *dlci) | |
939 | { | |
940 | unsigned long flags; | |
941 | ||
942 | spin_lock_irqsave(&dlci->gsm->tx_lock, flags); | |
943 | /* If we have nothing running then we need to fire up */ | |
944 | if (dlci->gsm->tx_bytes == 0) | |
945 | gsm_dlci_data_output(dlci->gsm, dlci); | |
946 | else if (dlci->gsm->tx_bytes < TX_THRESH_LO) | |
947 | gsm_dlci_data_sweep(dlci->gsm); | |
948 | spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags); | |
949 | } | |
950 | ||
951 | /* | |
952 | * Control message processing | |
953 | */ | |
954 | ||
955 | ||
956 | /** | |
957 | * gsm_control_reply - send a response frame to a control | |
958 | * @gsm: gsm channel | |
959 | * @cmd: the command to use | |
960 | * @data: data to follow encoded info | |
961 | * @dlen: length of data | |
962 | * | |
963 | * Encode up and queue a UI/UIH frame containing our response. | |
964 | */ | |
965 | ||
966 | static void gsm_control_reply(struct gsm_mux *gsm, int cmd, u8 *data, | |
967 | int dlen) | |
968 | { | |
969 | struct gsm_msg *msg; | |
970 | msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype); | |
971 | msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */ | |
972 | msg->data[1] = (dlen << 1) | EA; | |
973 | memcpy(msg->data + 2, data, dlen); | |
974 | gsm_data_queue(gsm->dlci[0], msg); | |
975 | } | |
976 | ||
977 | /** | |
978 | * gsm_process_modem - process received modem status | |
979 | * @tty: virtual tty bound to the DLCI | |
980 | * @dlci: DLCI to affect | |
981 | * @modem: modem bits (full EA) | |
982 | * | |
983 | * Used when a modem control message or line state inline in adaption | |
984 | * layer 2 is processed. Sort out the local modem state and throttles | |
985 | */ | |
986 | ||
987 | static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci, | |
988 | u32 modem) | |
989 | { | |
990 | int mlines = 0; | |
991 | u8 brk = modem >> 6; | |
992 | ||
993 | /* Flow control/ready to communicate */ | |
994 | if (modem & MDM_FC) { | |
995 | /* Need to throttle our output on this device */ | |
996 | dlci->constipated = 1; | |
997 | } | |
998 | if (modem & MDM_RTC) { | |
999 | mlines |= TIOCM_DSR | TIOCM_DTR; | |
1000 | dlci->constipated = 0; | |
1001 | gsm_dlci_data_kick(dlci); | |
1002 | } | |
1003 | /* Map modem bits */ | |
1004 | if (modem & MDM_RTR) | |
1005 | mlines |= TIOCM_RTS | TIOCM_CTS; | |
1006 | if (modem & MDM_IC) | |
1007 | mlines |= TIOCM_RI; | |
1008 | if (modem & MDM_DV) | |
1009 | mlines |= TIOCM_CD; | |
1010 | ||
1011 | /* Carrier drop -> hangup */ | |
1012 | if (tty) { | |
1013 | if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD)) | |
1014 | if (!(tty->termios->c_cflag & CLOCAL)) | |
1015 | tty_hangup(tty); | |
1016 | if (brk & 0x01) | |
1017 | tty_insert_flip_char(tty, 0, TTY_BREAK); | |
1018 | } | |
1019 | dlci->modem_rx = mlines; | |
1020 | } | |
1021 | ||
1022 | /** | |
1023 | * gsm_control_modem - modem status received | |
1024 | * @gsm: GSM channel | |
1025 | * @data: data following command | |
1026 | * @clen: command length | |
1027 | * | |
1028 | * We have received a modem status control message. This is used by | |
1029 | * the GSM mux protocol to pass virtual modem line status and optionally | |
1030 | * to indicate break signals. Unpack it, convert to Linux representation | |
1031 | * and if need be stuff a break message down the tty. | |
1032 | */ | |
1033 | ||
1034 | static void gsm_control_modem(struct gsm_mux *gsm, u8 *data, int clen) | |
1035 | { | |
1036 | unsigned int addr = 0; | |
1037 | unsigned int modem = 0; | |
1038 | struct gsm_dlci *dlci; | |
1039 | int len = clen; | |
1040 | u8 *dp = data; | |
1041 | struct tty_struct *tty; | |
1042 | ||
1043 | while (gsm_read_ea(&addr, *dp++) == 0) { | |
1044 | len--; | |
1045 | if (len == 0) | |
1046 | return; | |
1047 | } | |
1048 | /* Must be at least one byte following the EA */ | |
1049 | len--; | |
1050 | if (len <= 0) | |
1051 | return; | |
1052 | ||
1053 | addr >>= 1; | |
1054 | /* Closed port, or invalid ? */ | |
1055 | if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL) | |
1056 | return; | |
1057 | dlci = gsm->dlci[addr]; | |
1058 | ||
1059 | while (gsm_read_ea(&modem, *dp++) == 0) { | |
1060 | len--; | |
1061 | if (len == 0) | |
1062 | return; | |
1063 | } | |
1064 | tty = tty_port_tty_get(&dlci->port); | |
1065 | gsm_process_modem(tty, dlci, modem); | |
1066 | if (tty) { | |
1067 | tty_wakeup(tty); | |
1068 | tty_kref_put(tty); | |
1069 | } | |
1070 | gsm_control_reply(gsm, CMD_MSC, data, clen); | |
1071 | } | |
1072 | ||
1073 | /** | |
1074 | * gsm_control_rls - remote line status | |
1075 | * @gsm: GSM channel | |
1076 | * @data: data bytes | |
1077 | * @clen: data length | |
1078 | * | |
1079 | * The modem sends us a two byte message on the control channel whenever | |
1080 | * it wishes to send us an error state from the virtual link. Stuff | |
1081 | * this into the uplink tty if present | |
1082 | */ | |
1083 | ||
1084 | static void gsm_control_rls(struct gsm_mux *gsm, u8 *data, int clen) | |
1085 | { | |
1086 | struct tty_struct *tty; | |
1087 | unsigned int addr = 0 ; | |
1088 | u8 bits; | |
1089 | int len = clen; | |
1090 | u8 *dp = data; | |
1091 | ||
1092 | while (gsm_read_ea(&addr, *dp++) == 0) { | |
1093 | len--; | |
1094 | if (len == 0) | |
1095 | return; | |
1096 | } | |
1097 | /* Must be at least one byte following ea */ | |
1098 | len--; | |
1099 | if (len <= 0) | |
1100 | return; | |
1101 | addr >>= 1; | |
1102 | /* Closed port, or invalid ? */ | |
1103 | if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL) | |
1104 | return; | |
1105 | /* No error ? */ | |
1106 | bits = *dp; | |
1107 | if ((bits & 1) == 0) | |
1108 | return; | |
1109 | /* See if we have an uplink tty */ | |
1110 | tty = tty_port_tty_get(&gsm->dlci[addr]->port); | |
1111 | ||
1112 | if (tty) { | |
1113 | if (bits & 2) | |
1114 | tty_insert_flip_char(tty, 0, TTY_OVERRUN); | |
1115 | if (bits & 4) | |
1116 | tty_insert_flip_char(tty, 0, TTY_PARITY); | |
1117 | if (bits & 8) | |
1118 | tty_insert_flip_char(tty, 0, TTY_FRAME); | |
1119 | tty_flip_buffer_push(tty); | |
1120 | tty_kref_put(tty); | |
1121 | } | |
1122 | gsm_control_reply(gsm, CMD_RLS, data, clen); | |
1123 | } | |
1124 | ||
1125 | static void gsm_dlci_begin_close(struct gsm_dlci *dlci); | |
1126 | ||
1127 | /** | |
1128 | * gsm_control_message - DLCI 0 control processing | |
1129 | * @gsm: our GSM mux | |
1130 | * @command: the command EA | |
1131 | * @data: data beyond the command/length EAs | |
1132 | * @clen: length | |
1133 | * | |
1134 | * Input processor for control messages from the other end of the link. | |
1135 | * Processes the incoming request and queues a response frame or an | |
1136 | * NSC response if not supported | |
1137 | */ | |
1138 | ||
1139 | static void gsm_control_message(struct gsm_mux *gsm, unsigned int command, | |
1140 | u8 *data, int clen) | |
1141 | { | |
1142 | u8 buf[1]; | |
1143 | switch (command) { | |
1144 | case CMD_CLD: { | |
1145 | struct gsm_dlci *dlci = gsm->dlci[0]; | |
1146 | /* Modem wishes to close down */ | |
1147 | if (dlci) { | |
1148 | dlci->dead = 1; | |
1149 | gsm->dead = 1; | |
1150 | gsm_dlci_begin_close(dlci); | |
1151 | } | |
1152 | } | |
1153 | break; | |
1154 | case CMD_TEST: | |
1155 | /* Modem wishes to test, reply with the data */ | |
1156 | gsm_control_reply(gsm, CMD_TEST, data, clen); | |
1157 | break; | |
1158 | case CMD_FCON: | |
1159 | /* Modem wants us to STFU */ | |
1160 | gsm->constipated = 1; | |
1161 | gsm_control_reply(gsm, CMD_FCON, NULL, 0); | |
1162 | break; | |
1163 | case CMD_FCOFF: | |
1164 | /* Modem can accept data again */ | |
1165 | gsm->constipated = 0; | |
1166 | gsm_control_reply(gsm, CMD_FCOFF, NULL, 0); | |
1167 | /* Kick the link in case it is idling */ | |
1168 | gsm_data_kick(gsm); | |
1169 | break; | |
1170 | case CMD_MSC: | |
1171 | /* Out of band modem line change indicator for a DLCI */ | |
1172 | gsm_control_modem(gsm, data, clen); | |
1173 | break; | |
1174 | case CMD_RLS: | |
1175 | /* Out of band error reception for a DLCI */ | |
1176 | gsm_control_rls(gsm, data, clen); | |
1177 | break; | |
1178 | case CMD_PSC: | |
1179 | /* Modem wishes to enter power saving state */ | |
1180 | gsm_control_reply(gsm, CMD_PSC, NULL, 0); | |
1181 | break; | |
1182 | /* Optional unsupported commands */ | |
1183 | case CMD_PN: /* Parameter negotiation */ | |
1184 | case CMD_RPN: /* Remote port negotation */ | |
1185 | case CMD_SNC: /* Service negotation command */ | |
1186 | default: | |
1187 | /* Reply to bad commands with an NSC */ | |
1188 | buf[0] = command; | |
1189 | gsm_control_reply(gsm, CMD_NSC, buf, 1); | |
1190 | break; | |
1191 | } | |
1192 | } | |
1193 | ||
1194 | /** | |
1195 | * gsm_control_response - process a response to our control | |
1196 | * @gsm: our GSM mux | |
1197 | * @command: the command (response) EA | |
1198 | * @data: data beyond the command/length EA | |
1199 | * @clen: length | |
1200 | * | |
1201 | * Process a response to an outstanding command. We only allow a single | |
1202 | * control message in flight so this is fairly easy. All the clean up | |
1203 | * is done by the caller, we just update the fields, flag it as done | |
1204 | * and return | |
1205 | */ | |
1206 | ||
1207 | static void gsm_control_response(struct gsm_mux *gsm, unsigned int command, | |
1208 | u8 *data, int clen) | |
1209 | { | |
1210 | struct gsm_control *ctrl; | |
1211 | unsigned long flags; | |
1212 | ||
1213 | spin_lock_irqsave(&gsm->control_lock, flags); | |
1214 | ||
1215 | ctrl = gsm->pending_cmd; | |
1216 | /* Does the reply match our command */ | |
1217 | command |= 1; | |
1218 | if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) { | |
1219 | /* Our command was replied to, kill the retry timer */ | |
1220 | del_timer(&gsm->t2_timer); | |
1221 | gsm->pending_cmd = NULL; | |
1222 | /* Rejected by the other end */ | |
1223 | if (command == CMD_NSC) | |
1224 | ctrl->error = -EOPNOTSUPP; | |
1225 | ctrl->done = 1; | |
1226 | wake_up(&gsm->event); | |
1227 | } | |
1228 | spin_unlock_irqrestore(&gsm->control_lock, flags); | |
1229 | } | |
1230 | ||
1231 | /** | |
1232 | * gsm_control_transmit - send control packet | |
1233 | * @gsm: gsm mux | |
1234 | * @ctrl: frame to send | |
1235 | * | |
1236 | * Send out a pending control command (called under control lock) | |
1237 | */ | |
1238 | ||
1239 | static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl) | |
1240 | { | |
1241 | struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, | |
1242 | gsm->ftype|PF); | |
1243 | if (msg == NULL) | |
1244 | return; | |
1245 | msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */ | |
1246 | memcpy(msg->data + 1, ctrl->data, ctrl->len); | |
1247 | gsm_data_queue(gsm->dlci[0], msg); | |
1248 | } | |
1249 | ||
1250 | /** | |
1251 | * gsm_control_retransmit - retransmit a control frame | |
1252 | * @data: pointer to our gsm object | |
1253 | * | |
1254 | * Called off the T2 timer expiry in order to retransmit control frames | |
1255 | * that have been lost in the system somewhere. The control_lock protects | |
1256 | * us from colliding with another sender or a receive completion event. | |
1257 | * In that situation the timer may still occur in a small window but | |
1258 | * gsm->pending_cmd will be NULL and we just let the timer expire. | |
1259 | */ | |
1260 | ||
1261 | static void gsm_control_retransmit(unsigned long data) | |
1262 | { | |
1263 | struct gsm_mux *gsm = (struct gsm_mux *)data; | |
1264 | struct gsm_control *ctrl; | |
1265 | unsigned long flags; | |
1266 | spin_lock_irqsave(&gsm->control_lock, flags); | |
1267 | ctrl = gsm->pending_cmd; | |
1268 | if (ctrl) { | |
1269 | gsm->cretries--; | |
1270 | if (gsm->cretries == 0) { | |
1271 | gsm->pending_cmd = NULL; | |
1272 | ctrl->error = -ETIMEDOUT; | |
1273 | ctrl->done = 1; | |
1274 | spin_unlock_irqrestore(&gsm->control_lock, flags); | |
1275 | wake_up(&gsm->event); | |
1276 | return; | |
1277 | } | |
1278 | gsm_control_transmit(gsm, ctrl); | |
1279 | mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100); | |
1280 | } | |
1281 | spin_unlock_irqrestore(&gsm->control_lock, flags); | |
1282 | } | |
1283 | ||
1284 | /** | |
1285 | * gsm_control_send - send a control frame on DLCI 0 | |
1286 | * @gsm: the GSM channel | |
1287 | * @command: command to send including CR bit | |
1288 | * @data: bytes of data (must be kmalloced) | |
1289 | * @len: length of the block to send | |
1290 | * | |
1291 | * Queue and dispatch a control command. Only one command can be | |
1292 | * active at a time. In theory more can be outstanding but the matching | |
1293 | * gets really complicated so for now stick to one outstanding. | |
1294 | */ | |
1295 | ||
1296 | static struct gsm_control *gsm_control_send(struct gsm_mux *gsm, | |
1297 | unsigned int command, u8 *data, int clen) | |
1298 | { | |
1299 | struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control), | |
1300 | GFP_KERNEL); | |
1301 | unsigned long flags; | |
1302 | if (ctrl == NULL) | |
1303 | return NULL; | |
1304 | retry: | |
1305 | wait_event(gsm->event, gsm->pending_cmd == NULL); | |
1306 | spin_lock_irqsave(&gsm->control_lock, flags); | |
1307 | if (gsm->pending_cmd != NULL) { | |
1308 | spin_unlock_irqrestore(&gsm->control_lock, flags); | |
1309 | goto retry; | |
1310 | } | |
1311 | ctrl->cmd = command; | |
1312 | ctrl->data = data; | |
1313 | ctrl->len = clen; | |
1314 | gsm->pending_cmd = ctrl; | |
1315 | gsm->cretries = gsm->n2; | |
1316 | mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100); | |
1317 | gsm_control_transmit(gsm, ctrl); | |
1318 | spin_unlock_irqrestore(&gsm->control_lock, flags); | |
1319 | return ctrl; | |
1320 | } | |
1321 | ||
1322 | /** | |
1323 | * gsm_control_wait - wait for a control to finish | |
1324 | * @gsm: GSM mux | |
1325 | * @control: control we are waiting on | |
1326 | * | |
1327 | * Waits for the control to complete or time out. Frees any used | |
1328 | * resources and returns 0 for success, or an error if the remote | |
1329 | * rejected or ignored the request. | |
1330 | */ | |
1331 | ||
1332 | static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control) | |
1333 | { | |
1334 | int err; | |
1335 | wait_event(gsm->event, control->done == 1); | |
1336 | err = control->error; | |
1337 | kfree(control); | |
1338 | return err; | |
1339 | } | |
1340 | ||
1341 | ||
1342 | /* | |
1343 | * DLCI level handling: Needs krefs | |
1344 | */ | |
1345 | ||
1346 | /* | |
1347 | * State transitions and timers | |
1348 | */ | |
1349 | ||
1350 | /** | |
1351 | * gsm_dlci_close - a DLCI has closed | |
1352 | * @dlci: DLCI that closed | |
1353 | * | |
1354 | * Perform processing when moving a DLCI into closed state. If there | |
1355 | * is an attached tty this is hung up | |
1356 | */ | |
1357 | ||
1358 | static void gsm_dlci_close(struct gsm_dlci *dlci) | |
1359 | { | |
1360 | del_timer(&dlci->t1); | |
1361 | if (debug & 8) | |
1362 | printk("DLCI %d goes closed.\n", dlci->addr); | |
1363 | dlci->state = DLCI_CLOSED; | |
1364 | if (dlci->addr != 0) { | |
1365 | struct tty_struct *tty = tty_port_tty_get(&dlci->port); | |
1366 | if (tty) { | |
1367 | tty_hangup(tty); | |
1368 | tty_kref_put(tty); | |
1369 | } | |
1370 | kfifo_reset(dlci->fifo); | |
1371 | } else | |
1372 | dlci->gsm->dead = 1; | |
1373 | wake_up(&dlci->gsm->event); | |
1374 | /* A DLCI 0 close is a MUX termination so we need to kick that | |
1375 | back to userspace somehow */ | |
1376 | } | |
1377 | ||
1378 | /** | |
1379 | * gsm_dlci_open - a DLCI has opened | |
1380 | * @dlci: DLCI that opened | |
1381 | * | |
1382 | * Perform processing when moving a DLCI into open state. | |
1383 | */ | |
1384 | ||
1385 | static void gsm_dlci_open(struct gsm_dlci *dlci) | |
1386 | { | |
1387 | /* Note that SABM UA .. SABM UA first UA lost can mean that we go | |
1388 | open -> open */ | |
1389 | del_timer(&dlci->t1); | |
1390 | /* This will let a tty open continue */ | |
1391 | dlci->state = DLCI_OPEN; | |
1392 | if (debug & 8) | |
1393 | printk("DLCI %d goes open.\n", dlci->addr); | |
1394 | wake_up(&dlci->gsm->event); | |
1395 | } | |
1396 | ||
1397 | /** | |
1398 | * gsm_dlci_t1 - T1 timer expiry | |
1399 | * @dlci: DLCI that opened | |
1400 | * | |
1401 | * The T1 timer handles retransmits of control frames (essentially of | |
1402 | * SABM and DISC). We resend the command until the retry count runs out | |
1403 | * in which case an opening port goes back to closed and a closing port | |
1404 | * is simply put into closed state (any further frames from the other | |
1405 | * end will get a DM response) | |
1406 | */ | |
1407 | ||
1408 | static void gsm_dlci_t1(unsigned long data) | |
1409 | { | |
1410 | struct gsm_dlci *dlci = (struct gsm_dlci *)data; | |
1411 | struct gsm_mux *gsm = dlci->gsm; | |
1412 | ||
1413 | switch (dlci->state) { | |
1414 | case DLCI_OPENING: | |
1415 | dlci->retries--; | |
1416 | if (dlci->retries) { | |
1417 | gsm_command(dlci->gsm, dlci->addr, SABM|PF); | |
1418 | mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); | |
1419 | } else | |
1420 | gsm_dlci_close(dlci); | |
1421 | break; | |
1422 | case DLCI_CLOSING: | |
1423 | dlci->retries--; | |
1424 | if (dlci->retries) { | |
1425 | gsm_command(dlci->gsm, dlci->addr, DISC|PF); | |
1426 | mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); | |
1427 | } else | |
1428 | gsm_dlci_close(dlci); | |
1429 | break; | |
1430 | } | |
1431 | } | |
1432 | ||
1433 | /** | |
1434 | * gsm_dlci_begin_open - start channel open procedure | |
1435 | * @dlci: DLCI to open | |
1436 | * | |
1437 | * Commence opening a DLCI from the Linux side. We issue SABM messages | |
1438 | * to the modem which should then reply with a UA, at which point we | |
1439 | * will move into open state. Opening is done asynchronously with retry | |
1440 | * running off timers and the responses. | |
1441 | */ | |
1442 | ||
1443 | static void gsm_dlci_begin_open(struct gsm_dlci *dlci) | |
1444 | { | |
1445 | struct gsm_mux *gsm = dlci->gsm; | |
1446 | if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING) | |
1447 | return; | |
1448 | dlci->retries = gsm->n2; | |
1449 | dlci->state = DLCI_OPENING; | |
1450 | gsm_command(dlci->gsm, dlci->addr, SABM|PF); | |
1451 | mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); | |
1452 | } | |
1453 | ||
1454 | /** | |
1455 | * gsm_dlci_begin_close - start channel open procedure | |
1456 | * @dlci: DLCI to open | |
1457 | * | |
1458 | * Commence closing a DLCI from the Linux side. We issue DISC messages | |
1459 | * to the modem which should then reply with a UA, at which point we | |
1460 | * will move into closed state. Closing is done asynchronously with retry | |
1461 | * off timers. We may also receive a DM reply from the other end which | |
1462 | * indicates the channel was already closed. | |
1463 | */ | |
1464 | ||
1465 | static void gsm_dlci_begin_close(struct gsm_dlci *dlci) | |
1466 | { | |
1467 | struct gsm_mux *gsm = dlci->gsm; | |
1468 | if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING) | |
1469 | return; | |
1470 | dlci->retries = gsm->n2; | |
1471 | dlci->state = DLCI_CLOSING; | |
1472 | gsm_command(dlci->gsm, dlci->addr, DISC|PF); | |
1473 | mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); | |
1474 | } | |
1475 | ||
1476 | /** | |
1477 | * gsm_dlci_data - data arrived | |
1478 | * @dlci: channel | |
1479 | * @data: block of bytes received | |
1480 | * @len: length of received block | |
1481 | * | |
1482 | * A UI or UIH frame has arrived which contains data for a channel | |
1483 | * other than the control channel. If the relevant virtual tty is | |
1484 | * open we shovel the bits down it, if not we drop them. | |
1485 | */ | |
1486 | ||
1487 | static void gsm_dlci_data(struct gsm_dlci *dlci, u8 *data, int len) | |
1488 | { | |
1489 | /* krefs .. */ | |
1490 | struct tty_port *port = &dlci->port; | |
1491 | struct tty_struct *tty = tty_port_tty_get(port); | |
1492 | unsigned int modem = 0; | |
1493 | ||
1494 | if (debug & 16) | |
1495 | printk("%d bytes for tty %p\n", len, tty); | |
1496 | if (tty) { | |
1497 | switch (dlci->adaption) { | |
1498 | /* Unsupported types */ | |
1499 | /* Packetised interruptible data */ | |
1500 | case 4: | |
1501 | break; | |
1502 | /* Packetised uininterruptible voice/data */ | |
1503 | case 3: | |
1504 | break; | |
1505 | /* Asynchronous serial with line state in each frame */ | |
1506 | case 2: | |
1507 | while (gsm_read_ea(&modem, *data++) == 0) { | |
1508 | len--; | |
1509 | if (len == 0) | |
1510 | return; | |
1511 | } | |
1512 | gsm_process_modem(tty, dlci, modem); | |
1513 | /* Line state will go via DLCI 0 controls only */ | |
1514 | case 1: | |
1515 | default: | |
1516 | tty_insert_flip_string(tty, data, len); | |
1517 | tty_flip_buffer_push(tty); | |
1518 | } | |
1519 | tty_kref_put(tty); | |
1520 | } | |
1521 | } | |
1522 | ||
1523 | /** | |
1524 | * gsm_dlci_control - data arrived on control channel | |
1525 | * @dlci: channel | |
1526 | * @data: block of bytes received | |
1527 | * @len: length of received block | |
1528 | * | |
1529 | * A UI or UIH frame has arrived which contains data for DLCI 0 the | |
1530 | * control channel. This should contain a command EA followed by | |
1531 | * control data bytes. The command EA contains a command/response bit | |
1532 | * and we divide up the work accordingly. | |
1533 | */ | |
1534 | ||
1535 | static void gsm_dlci_command(struct gsm_dlci *dlci, u8 *data, int len) | |
1536 | { | |
1537 | /* See what command is involved */ | |
1538 | unsigned int command = 0; | |
1539 | while (len-- > 0) { | |
1540 | if (gsm_read_ea(&command, *data++) == 1) { | |
1541 | int clen = *data++; | |
1542 | len--; | |
1543 | /* FIXME: this is properly an EA */ | |
1544 | clen >>= 1; | |
1545 | /* Malformed command ? */ | |
1546 | if (clen > len) | |
1547 | return; | |
1548 | if (command & 1) | |
1549 | gsm_control_message(dlci->gsm, command, | |
1550 | data, clen); | |
1551 | else | |
1552 | gsm_control_response(dlci->gsm, command, | |
1553 | data, clen); | |
1554 | return; | |
1555 | } | |
1556 | } | |
1557 | } | |
1558 | ||
1559 | /* | |
1560 | * Allocate/Free DLCI channels | |
1561 | */ | |
1562 | ||
1563 | /** | |
1564 | * gsm_dlci_alloc - allocate a DLCI | |
1565 | * @gsm: GSM mux | |
1566 | * @addr: address of the DLCI | |
1567 | * | |
1568 | * Allocate and install a new DLCI object into the GSM mux. | |
1569 | * | |
1570 | * FIXME: review locking races | |
1571 | */ | |
1572 | ||
1573 | static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr) | |
1574 | { | |
1575 | struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC); | |
1576 | if (dlci == NULL) | |
1577 | return NULL; | |
1578 | spin_lock_init(&dlci->lock); | |
1579 | dlci->fifo = &dlci->_fifo; | |
1580 | if (kfifo_alloc(&dlci->_fifo, 4096, GFP_KERNEL) < 0) { | |
1581 | kfree(dlci); | |
1582 | return NULL; | |
1583 | } | |
1584 | ||
1585 | skb_queue_head_init(&dlci->skb_list); | |
1586 | init_timer(&dlci->t1); | |
1587 | dlci->t1.function = gsm_dlci_t1; | |
1588 | dlci->t1.data = (unsigned long)dlci; | |
1589 | tty_port_init(&dlci->port); | |
1590 | dlci->port.ops = &gsm_port_ops; | |
1591 | dlci->gsm = gsm; | |
1592 | dlci->addr = addr; | |
1593 | dlci->adaption = gsm->adaption; | |
1594 | dlci->state = DLCI_CLOSED; | |
1595 | if (addr) | |
1596 | dlci->data = gsm_dlci_data; | |
1597 | else | |
1598 | dlci->data = gsm_dlci_command; | |
1599 | gsm->dlci[addr] = dlci; | |
1600 | return dlci; | |
1601 | } | |
1602 | ||
1603 | /** | |
1604 | * gsm_dlci_free - release DLCI | |
1605 | * @dlci: DLCI to destroy | |
1606 | * | |
1607 | * Free up a DLCI. Currently to keep the lifetime rules sane we only | |
1608 | * clean up DLCI objects when the MUX closes rather than as the port | |
1609 | * is closed down on both the tty and mux levels. | |
1610 | * | |
1611 | * Can sleep. | |
1612 | */ | |
1613 | static void gsm_dlci_free(struct gsm_dlci *dlci) | |
1614 | { | |
1615 | struct tty_struct *tty = tty_port_tty_get(&dlci->port); | |
1616 | if (tty) { | |
1617 | tty_vhangup(tty); | |
1618 | tty_kref_put(tty); | |
1619 | } | |
1620 | del_timer_sync(&dlci->t1); | |
1621 | dlci->gsm->dlci[dlci->addr] = NULL; | |
1622 | kfifo_free(dlci->fifo); | |
1623 | kfree(dlci); | |
1624 | } | |
1625 | ||
1626 | ||
1627 | /* | |
1628 | * LAPBish link layer logic | |
1629 | */ | |
1630 | ||
1631 | /** | |
1632 | * gsm_queue - a GSM frame is ready to process | |
1633 | * @gsm: pointer to our gsm mux | |
1634 | * | |
1635 | * At this point in time a frame has arrived and been demangled from | |
1636 | * the line encoding. All the differences between the encodings have | |
1637 | * been handled below us and the frame is unpacked into the structures. | |
1638 | * The fcs holds the header FCS but any data FCS must be added here. | |
1639 | */ | |
1640 | ||
1641 | static void gsm_queue(struct gsm_mux *gsm) | |
1642 | { | |
1643 | struct gsm_dlci *dlci; | |
1644 | u8 cr; | |
1645 | int address; | |
1646 | /* We have to sneak a look at the packet body to do the FCS. | |
1647 | A somewhat layering violation in the spec */ | |
1648 | ||
1649 | if ((gsm->control & ~PF) == UI) | |
1650 | gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len); | |
1651 | if (gsm->fcs != GOOD_FCS) { | |
1652 | gsm->bad_fcs++; | |
1653 | if (debug & 4) | |
1654 | printk("BAD FCS %02x\n", gsm->fcs); | |
1655 | return; | |
1656 | } | |
1657 | address = gsm->address >> 1; | |
1658 | if (address >= NUM_DLCI) | |
1659 | goto invalid; | |
1660 | ||
1661 | cr = gsm->address & 1; /* C/R bit */ | |
1662 | ||
1663 | gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len); | |
1664 | ||
1665 | cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */ | |
1666 | dlci = gsm->dlci[address]; | |
1667 | ||
1668 | switch (gsm->control) { | |
1669 | case SABM|PF: | |
1670 | if (cr == 0) | |
1671 | goto invalid; | |
1672 | if (dlci == NULL) | |
1673 | dlci = gsm_dlci_alloc(gsm, address); | |
1674 | if (dlci == NULL) | |
1675 | return; | |
1676 | if (dlci->dead) | |
1677 | gsm_response(gsm, address, DM); | |
1678 | else { | |
1679 | gsm_response(gsm, address, UA); | |
1680 | gsm_dlci_open(dlci); | |
1681 | } | |
1682 | break; | |
1683 | case DISC|PF: | |
1684 | if (cr == 0) | |
1685 | goto invalid; | |
1686 | if (dlci == NULL || dlci->state == DLCI_CLOSED) { | |
1687 | gsm_response(gsm, address, DM); | |
1688 | return; | |
1689 | } | |
1690 | /* Real close complete */ | |
1691 | gsm_response(gsm, address, UA); | |
1692 | gsm_dlci_close(dlci); | |
1693 | break; | |
1694 | case UA: | |
1695 | case UA|PF: | |
1696 | if (cr == 0 || dlci == NULL) | |
1697 | break; | |
1698 | switch (dlci->state) { | |
1699 | case DLCI_CLOSING: | |
1700 | gsm_dlci_close(dlci); | |
1701 | break; | |
1702 | case DLCI_OPENING: | |
1703 | gsm_dlci_open(dlci); | |
1704 | break; | |
1705 | } | |
1706 | break; | |
1707 | case DM: /* DM can be valid unsolicited */ | |
1708 | case DM|PF: | |
1709 | if (cr) | |
1710 | goto invalid; | |
1711 | if (dlci == NULL) | |
1712 | return; | |
1713 | gsm_dlci_close(dlci); | |
1714 | break; | |
1715 | case UI: | |
1716 | case UI|PF: | |
1717 | case UIH: | |
1718 | case UIH|PF: | |
1719 | #if 0 | |
1720 | if (cr) | |
1721 | goto invalid; | |
1722 | #endif | |
1723 | if (dlci == NULL || dlci->state != DLCI_OPEN) { | |
1724 | gsm_command(gsm, address, DM|PF); | |
1725 | return; | |
1726 | } | |
1727 | dlci->data(dlci, gsm->buf, gsm->len); | |
1728 | break; | |
1729 | default: | |
1730 | goto invalid; | |
1731 | } | |
1732 | return; | |
1733 | invalid: | |
1734 | gsm->malformed++; | |
1735 | return; | |
1736 | } | |
1737 | ||
1738 | ||
1739 | /** | |
1740 | * gsm0_receive - perform processing for non-transparency | |
1741 | * @gsm: gsm data for this ldisc instance | |
1742 | * @c: character | |
1743 | * | |
1744 | * Receive bytes in gsm mode 0 | |
1745 | */ | |
1746 | ||
1747 | static void gsm0_receive(struct gsm_mux *gsm, unsigned char c) | |
1748 | { | |
1749 | switch (gsm->state) { | |
1750 | case GSM_SEARCH: /* SOF marker */ | |
1751 | if (c == GSM0_SOF) { | |
1752 | gsm->state = GSM_ADDRESS; | |
1753 | gsm->address = 0; | |
1754 | gsm->len = 0; | |
1755 | gsm->fcs = INIT_FCS; | |
1756 | } | |
1757 | break; /* Address EA */ | |
1758 | case GSM_ADDRESS: | |
1759 | gsm->fcs = gsm_fcs_add(gsm->fcs, c); | |
1760 | if (gsm_read_ea(&gsm->address, c)) | |
1761 | gsm->state = GSM_CONTROL; | |
1762 | break; | |
1763 | case GSM_CONTROL: /* Control Byte */ | |
1764 | gsm->fcs = gsm_fcs_add(gsm->fcs, c); | |
1765 | gsm->control = c; | |
1766 | gsm->state = GSM_LEN; | |
1767 | break; | |
1768 | case GSM_LEN: /* Length EA */ | |
1769 | gsm->fcs = gsm_fcs_add(gsm->fcs, c); | |
1770 | if (gsm_read_ea(&gsm->len, c)) { | |
1771 | if (gsm->len > gsm->mru) { | |
1772 | gsm->bad_size++; | |
1773 | gsm->state = GSM_SEARCH; | |
1774 | break; | |
1775 | } | |
1776 | gsm->count = 0; | |
1777 | gsm->state = GSM_DATA; | |
1778 | } | |
1779 | break; | |
1780 | case GSM_DATA: /* Data */ | |
1781 | gsm->buf[gsm->count++] = c; | |
1782 | if (gsm->count == gsm->len) | |
1783 | gsm->state = GSM_FCS; | |
1784 | break; | |
1785 | case GSM_FCS: /* FCS follows the packet */ | |
1786 | gsm->fcs = c; | |
1787 | gsm_queue(gsm); | |
1788 | /* And then back for the next frame */ | |
1789 | gsm->state = GSM_SEARCH; | |
1790 | break; | |
1791 | } | |
1792 | } | |
1793 | ||
1794 | /** | |
1795 | * gsm0_receive - perform processing for non-transparency | |
1796 | * @gsm: gsm data for this ldisc instance | |
1797 | * @c: character | |
1798 | * | |
1799 | * Receive bytes in mode 1 (Advanced option) | |
1800 | */ | |
1801 | ||
1802 | static void gsm1_receive(struct gsm_mux *gsm, unsigned char c) | |
1803 | { | |
1804 | if (c == GSM1_SOF) { | |
1805 | /* EOF is only valid in frame if we have got to the data state | |
1806 | and received at least one byte (the FCS) */ | |
1807 | if (gsm->state == GSM_DATA && gsm->count) { | |
1808 | /* Extract the FCS */ | |
1809 | gsm->count--; | |
1810 | gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]); | |
1811 | gsm->len = gsm->count; | |
1812 | gsm_queue(gsm); | |
1813 | gsm->state = GSM_START; | |
1814 | return; | |
1815 | } | |
1816 | /* Any partial frame was a runt so go back to start */ | |
1817 | if (gsm->state != GSM_START) { | |
1818 | gsm->malformed++; | |
1819 | gsm->state = GSM_START; | |
1820 | } | |
1821 | /* A SOF in GSM_START means we are still reading idling or | |
1822 | framing bytes */ | |
1823 | return; | |
1824 | } | |
1825 | ||
1826 | if (c == GSM1_ESCAPE) { | |
1827 | gsm->escape = 1; | |
1828 | return; | |
1829 | } | |
1830 | ||
1831 | /* Only an unescaped SOF gets us out of GSM search */ | |
1832 | if (gsm->state == GSM_SEARCH) | |
1833 | return; | |
1834 | ||
1835 | if (gsm->escape) { | |
1836 | c ^= GSM1_ESCAPE_BITS; | |
1837 | gsm->escape = 0; | |
1838 | } | |
1839 | switch (gsm->state) { | |
1840 | case GSM_START: /* First byte after SOF */ | |
1841 | gsm->address = 0; | |
1842 | gsm->state = GSM_ADDRESS; | |
1843 | gsm->fcs = INIT_FCS; | |
1844 | /* Drop through */ | |
1845 | case GSM_ADDRESS: /* Address continuation */ | |
1846 | gsm->fcs = gsm_fcs_add(gsm->fcs, c); | |
1847 | if (gsm_read_ea(&gsm->address, c)) | |
1848 | gsm->state = GSM_CONTROL; | |
1849 | break; | |
1850 | case GSM_CONTROL: /* Control Byte */ | |
1851 | gsm->fcs = gsm_fcs_add(gsm->fcs, c); | |
1852 | gsm->control = c; | |
1853 | gsm->count = 0; | |
1854 | gsm->state = GSM_DATA; | |
1855 | break; | |
1856 | case GSM_DATA: /* Data */ | |
1857 | if (gsm->count > gsm->mru ) { /* Allow one for the FCS */ | |
1858 | gsm->state = GSM_OVERRUN; | |
1859 | gsm->bad_size++; | |
1860 | } else | |
1861 | gsm->buf[gsm->count++] = c; | |
1862 | break; | |
1863 | case GSM_OVERRUN: /* Over-long - eg a dropped SOF */ | |
1864 | break; | |
1865 | } | |
1866 | } | |
1867 | ||
1868 | /** | |
1869 | * gsm_error - handle tty error | |
1870 | * @gsm: ldisc data | |
1871 | * @data: byte received (may be invalid) | |
1872 | * @flag: error received | |
1873 | * | |
1874 | * Handle an error in the receipt of data for a frame. Currently we just | |
1875 | * go back to hunting for a SOF. | |
1876 | * | |
1877 | * FIXME: better diagnostics ? | |
1878 | */ | |
1879 | ||
1880 | static void gsm_error(struct gsm_mux *gsm, | |
1881 | unsigned char data, unsigned char flag) | |
1882 | { | |
1883 | gsm->state = GSM_SEARCH; | |
1884 | gsm->io_error++; | |
1885 | } | |
1886 | ||
1887 | /** | |
1888 | * gsm_cleanup_mux - generic GSM protocol cleanup | |
1889 | * @gsm: our mux | |
1890 | * | |
1891 | * Clean up the bits of the mux which are the same for all framing | |
1892 | * protocols. Remove the mux from the mux table, stop all the timers | |
1893 | * and then shut down each device hanging up the channels as we go. | |
1894 | */ | |
1895 | ||
1896 | void gsm_cleanup_mux(struct gsm_mux *gsm) | |
1897 | { | |
1898 | int i; | |
1899 | struct gsm_dlci *dlci = gsm->dlci[0]; | |
1900 | struct gsm_msg *txq; | |
1901 | ||
1902 | gsm->dead = 1; | |
1903 | ||
1904 | spin_lock(&gsm_mux_lock); | |
1905 | for (i = 0; i < MAX_MUX; i++) { | |
1906 | if (gsm_mux[i] == gsm) { | |
1907 | gsm_mux[i] = NULL; | |
1908 | break; | |
1909 | } | |
1910 | } | |
1911 | spin_unlock(&gsm_mux_lock); | |
1912 | WARN_ON(i == MAX_MUX); | |
1913 | ||
1914 | del_timer_sync(&gsm->t2_timer); | |
1915 | /* Now we are sure T2 has stopped */ | |
1916 | if (dlci) { | |
1917 | dlci->dead = 1; | |
1918 | gsm_dlci_begin_close(dlci); | |
1919 | wait_event_interruptible(gsm->event, | |
1920 | dlci->state == DLCI_CLOSED); | |
1921 | } | |
1922 | /* Free up any link layer users */ | |
1923 | for (i = 0; i < NUM_DLCI; i++) | |
1924 | if (gsm->dlci[i]) | |
1925 | gsm_dlci_free(gsm->dlci[i]); | |
1926 | /* Now wipe the queues */ | |
1927 | for (txq = gsm->tx_head; txq != NULL; txq = gsm->tx_head) { | |
1928 | gsm->tx_head = txq->next; | |
1929 | kfree(txq); | |
1930 | } | |
1931 | gsm->tx_tail = NULL; | |
1932 | } | |
1933 | EXPORT_SYMBOL_GPL(gsm_cleanup_mux); | |
1934 | ||
1935 | /** | |
1936 | * gsm_activate_mux - generic GSM setup | |
1937 | * @gsm: our mux | |
1938 | * | |
1939 | * Set up the bits of the mux which are the same for all framing | |
1940 | * protocols. Add the mux to the mux table so it can be opened and | |
1941 | * finally kick off connecting to DLCI 0 on the modem. | |
1942 | */ | |
1943 | ||
1944 | int gsm_activate_mux(struct gsm_mux *gsm) | |
1945 | { | |
1946 | struct gsm_dlci *dlci; | |
1947 | int i = 0; | |
1948 | ||
1949 | init_timer(&gsm->t2_timer); | |
1950 | gsm->t2_timer.function = gsm_control_retransmit; | |
1951 | gsm->t2_timer.data = (unsigned long)gsm; | |
1952 | init_waitqueue_head(&gsm->event); | |
1953 | spin_lock_init(&gsm->control_lock); | |
1954 | spin_lock_init(&gsm->tx_lock); | |
1955 | ||
1956 | if (gsm->encoding == 0) | |
1957 | gsm->receive = gsm0_receive; | |
1958 | else | |
1959 | gsm->receive = gsm1_receive; | |
1960 | gsm->error = gsm_error; | |
1961 | ||
1962 | spin_lock(&gsm_mux_lock); | |
1963 | for (i = 0; i < MAX_MUX; i++) { | |
1964 | if (gsm_mux[i] == NULL) { | |
1965 | gsm_mux[i] = gsm; | |
1966 | break; | |
1967 | } | |
1968 | } | |
1969 | spin_unlock(&gsm_mux_lock); | |
1970 | if (i == MAX_MUX) | |
1971 | return -EBUSY; | |
1972 | ||
1973 | dlci = gsm_dlci_alloc(gsm, 0); | |
1974 | if (dlci == NULL) | |
1975 | return -ENOMEM; | |
1976 | gsm->dead = 0; /* Tty opens are now permissible */ | |
1977 | return 0; | |
1978 | } | |
1979 | EXPORT_SYMBOL_GPL(gsm_activate_mux); | |
1980 | ||
1981 | /** | |
1982 | * gsm_free_mux - free up a mux | |
1983 | * @mux: mux to free | |
1984 | * | |
1985 | * Dispose of allocated resources for a dead mux. No refcounting | |
1986 | * at present so the mux must be truely dead. | |
1987 | */ | |
1988 | void gsm_free_mux(struct gsm_mux *gsm) | |
1989 | { | |
1990 | kfree(gsm->txframe); | |
1991 | kfree(gsm->buf); | |
1992 | kfree(gsm); | |
1993 | } | |
1994 | EXPORT_SYMBOL_GPL(gsm_free_mux); | |
1995 | ||
1996 | /** | |
1997 | * gsm_alloc_mux - allocate a mux | |
1998 | * | |
1999 | * Creates a new mux ready for activation. | |
2000 | */ | |
2001 | ||
2002 | struct gsm_mux *gsm_alloc_mux(void) | |
2003 | { | |
2004 | struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL); | |
2005 | if (gsm == NULL) | |
2006 | return NULL; | |
2007 | gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL); | |
2008 | if (gsm->buf == NULL) { | |
2009 | kfree(gsm); | |
2010 | return NULL; | |
2011 | } | |
2012 | gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL); | |
2013 | if (gsm->txframe == NULL) { | |
2014 | kfree(gsm->buf); | |
2015 | kfree(gsm); | |
2016 | return NULL; | |
2017 | } | |
2018 | spin_lock_init(&gsm->lock); | |
2019 | ||
2020 | gsm->t1 = T1; | |
2021 | gsm->t2 = T2; | |
2022 | gsm->n2 = N2; | |
2023 | gsm->ftype = UIH; | |
2024 | gsm->initiator = 0; | |
2025 | gsm->adaption = 1; | |
2026 | gsm->encoding = 1; | |
2027 | gsm->mru = 64; /* Default to encoding 1 so these should be 64 */ | |
2028 | gsm->mtu = 64; | |
2029 | gsm->dead = 1; /* Avoid early tty opens */ | |
2030 | ||
2031 | return gsm; | |
2032 | } | |
2033 | EXPORT_SYMBOL_GPL(gsm_alloc_mux); | |
2034 | ||
2035 | ||
2036 | ||
2037 | ||
2038 | /** | |
2039 | * gsmld_output - write to link | |
2040 | * @gsm: our mux | |
2041 | * @data: bytes to output | |
2042 | * @len: size | |
2043 | * | |
2044 | * Write a block of data from the GSM mux to the data channel. This | |
2045 | * will eventually be serialized from above but at the moment isn't. | |
2046 | */ | |
2047 | ||
2048 | static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len) | |
2049 | { | |
2050 | if (tty_write_room(gsm->tty) < len) { | |
2051 | set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags); | |
2052 | return -ENOSPC; | |
2053 | } | |
2054 | if (debug & 4) { | |
2055 | printk("-->%d bytes out\n", len); | |
2056 | hex_packet(data, len); | |
2057 | } | |
2058 | gsm->tty->ops->write(gsm->tty, data, len); | |
2059 | return len; | |
2060 | } | |
2061 | ||
2062 | /** | |
2063 | * gsmld_attach_gsm - mode set up | |
2064 | * @tty: our tty structure | |
2065 | * @gsm: our mux | |
2066 | * | |
2067 | * Set up the MUX for basic mode and commence connecting to the | |
2068 | * modem. Currently called from the line discipline set up but | |
2069 | * will need moving to an ioctl path. | |
2070 | */ | |
2071 | ||
2072 | static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) | |
2073 | { | |
2074 | int ret; | |
2075 | ||
2076 | gsm->tty = tty_kref_get(tty); | |
2077 | gsm->output = gsmld_output; | |
2078 | ret = gsm_activate_mux(gsm); | |
2079 | if (ret != 0) | |
2080 | tty_kref_put(gsm->tty); | |
2081 | return ret; | |
2082 | } | |
2083 | ||
2084 | ||
2085 | /** | |
2086 | * gsmld_detach_gsm - stop doing 0710 mux | |
2087 | * @tty: tty atttached to the mux | |
2088 | * @gsm: mux | |
2089 | * | |
2090 | * Shutdown and then clean up the resources used by the line discipline | |
2091 | */ | |
2092 | ||
2093 | static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) | |
2094 | { | |
2095 | WARN_ON(tty != gsm->tty); | |
2096 | gsm_cleanup_mux(gsm); | |
2097 | tty_kref_put(gsm->tty); | |
2098 | gsm->tty = NULL; | |
2099 | } | |
2100 | ||
2101 | static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp, | |
2102 | char *fp, int count) | |
2103 | { | |
2104 | struct gsm_mux *gsm = tty->disc_data; | |
2105 | const unsigned char *dp; | |
2106 | char *f; | |
2107 | int i; | |
2108 | char buf[64]; | |
2109 | char flags; | |
2110 | ||
2111 | if (debug & 4) { | |
2112 | printk("Inbytes %dd\n", count); | |
2113 | hex_packet(cp, count); | |
2114 | } | |
2115 | ||
2116 | for (i = count, dp = cp, f = fp; i; i--, dp++) { | |
2117 | flags = *f++; | |
2118 | switch (flags) { | |
2119 | case TTY_NORMAL: | |
2120 | gsm->receive(gsm, *dp); | |
2121 | break; | |
2122 | case TTY_OVERRUN: | |
2123 | case TTY_BREAK: | |
2124 | case TTY_PARITY: | |
2125 | case TTY_FRAME: | |
2126 | gsm->error(gsm, *dp, flags); | |
2127 | break; | |
2128 | default: | |
2129 | printk(KERN_ERR "%s: unknown flag %d\n", | |
2130 | tty_name(tty, buf), flags); | |
2131 | break; | |
2132 | } | |
2133 | } | |
2134 | /* FASYNC if needed ? */ | |
2135 | /* If clogged call tty_throttle(tty); */ | |
2136 | } | |
2137 | ||
2138 | /** | |
2139 | * gsmld_chars_in_buffer - report available bytes | |
2140 | * @tty: tty device | |
2141 | * | |
2142 | * Report the number of characters buffered to be delivered to user | |
2143 | * at this instant in time. | |
2144 | * | |
2145 | * Locking: gsm lock | |
2146 | */ | |
2147 | ||
2148 | static ssize_t gsmld_chars_in_buffer(struct tty_struct *tty) | |
2149 | { | |
2150 | return 0; | |
2151 | } | |
2152 | ||
2153 | /** | |
2154 | * gsmld_flush_buffer - clean input queue | |
2155 | * @tty: terminal device | |
2156 | * | |
2157 | * Flush the input buffer. Called when the line discipline is | |
2158 | * being closed, when the tty layer wants the buffer flushed (eg | |
2159 | * at hangup). | |
2160 | */ | |
2161 | ||
2162 | static void gsmld_flush_buffer(struct tty_struct *tty) | |
2163 | { | |
2164 | } | |
2165 | ||
2166 | /** | |
2167 | * gsmld_close - close the ldisc for this tty | |
2168 | * @tty: device | |
2169 | * | |
2170 | * Called from the terminal layer when this line discipline is | |
2171 | * being shut down, either because of a close or becsuse of a | |
2172 | * discipline change. The function will not be called while other | |
2173 | * ldisc methods are in progress. | |
2174 | */ | |
2175 | ||
2176 | static void gsmld_close(struct tty_struct *tty) | |
2177 | { | |
2178 | struct gsm_mux *gsm = tty->disc_data; | |
2179 | ||
2180 | gsmld_detach_gsm(tty, gsm); | |
2181 | ||
2182 | gsmld_flush_buffer(tty); | |
2183 | /* Do other clean up here */ | |
2184 | gsm_free_mux(gsm); | |
2185 | } | |
2186 | ||
2187 | /** | |
2188 | * gsmld_open - open an ldisc | |
2189 | * @tty: terminal to open | |
2190 | * | |
2191 | * Called when this line discipline is being attached to the | |
2192 | * terminal device. Can sleep. Called serialized so that no | |
2193 | * other events will occur in parallel. No further open will occur | |
2194 | * until a close. | |
2195 | */ | |
2196 | ||
2197 | static int gsmld_open(struct tty_struct *tty) | |
2198 | { | |
2199 | struct gsm_mux *gsm; | |
2200 | ||
2201 | if (tty->ops->write == NULL) | |
2202 | return -EINVAL; | |
2203 | ||
2204 | /* Attach our ldisc data */ | |
2205 | gsm = gsm_alloc_mux(); | |
2206 | if (gsm == NULL) | |
2207 | return -ENOMEM; | |
2208 | ||
2209 | tty->disc_data = gsm; | |
2210 | tty->receive_room = 65536; | |
2211 | ||
2212 | /* Attach the initial passive connection */ | |
2213 | gsm->encoding = 1; | |
2214 | return gsmld_attach_gsm(tty, gsm); | |
2215 | } | |
2216 | ||
2217 | /** | |
2218 | * gsmld_write_wakeup - asynchronous I/O notifier | |
2219 | * @tty: tty device | |
2220 | * | |
2221 | * Required for the ptys, serial driver etc. since processes | |
2222 | * that attach themselves to the master and rely on ASYNC | |
2223 | * IO must be woken up | |
2224 | */ | |
2225 | ||
2226 | static void gsmld_write_wakeup(struct tty_struct *tty) | |
2227 | { | |
2228 | struct gsm_mux *gsm = tty->disc_data; | |
328be395 | 2229 | unsigned long flags; |
e1eaea46 AC |
2230 | |
2231 | /* Queue poll */ | |
2232 | clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); | |
2233 | gsm_data_kick(gsm); | |
328be395 DC |
2234 | if (gsm->tx_bytes < TX_THRESH_LO) { |
2235 | spin_lock_irqsave(&gsm->tx_lock, flags); | |
e1eaea46 | 2236 | gsm_dlci_data_sweep(gsm); |
328be395 DC |
2237 | spin_unlock_irqrestore(&gsm->tx_lock, flags); |
2238 | } | |
e1eaea46 AC |
2239 | } |
2240 | ||
2241 | /** | |
2242 | * gsmld_read - read function for tty | |
2243 | * @tty: tty device | |
2244 | * @file: file object | |
2245 | * @buf: userspace buffer pointer | |
2246 | * @nr: size of I/O | |
2247 | * | |
2248 | * Perform reads for the line discipline. We are guaranteed that the | |
2249 | * line discipline will not be closed under us but we may get multiple | |
2250 | * parallel readers and must handle this ourselves. We may also get | |
2251 | * a hangup. Always called in user context, may sleep. | |
2252 | * | |
2253 | * This code must be sure never to sleep through a hangup. | |
2254 | */ | |
2255 | ||
2256 | static ssize_t gsmld_read(struct tty_struct *tty, struct file *file, | |
2257 | unsigned char __user *buf, size_t nr) | |
2258 | { | |
2259 | return -EOPNOTSUPP; | |
2260 | } | |
2261 | ||
2262 | /** | |
2263 | * gsmld_write - write function for tty | |
2264 | * @tty: tty device | |
2265 | * @file: file object | |
2266 | * @buf: userspace buffer pointer | |
2267 | * @nr: size of I/O | |
2268 | * | |
2269 | * Called when the owner of the device wants to send a frame | |
2270 | * itself (or some other control data). The data is transferred | |
2271 | * as-is and must be properly framed and checksummed as appropriate | |
2272 | * by userspace. Frames are either sent whole or not at all as this | |
2273 | * avoids pain user side. | |
2274 | */ | |
2275 | ||
2276 | static ssize_t gsmld_write(struct tty_struct *tty, struct file *file, | |
2277 | const unsigned char *buf, size_t nr) | |
2278 | { | |
2279 | int space = tty_write_room(tty); | |
2280 | if (space >= nr) | |
2281 | return tty->ops->write(tty, buf, nr); | |
2282 | set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); | |
2283 | return -ENOBUFS; | |
2284 | } | |
2285 | ||
2286 | /** | |
2287 | * gsmld_poll - poll method for N_GSM0710 | |
2288 | * @tty: terminal device | |
2289 | * @file: file accessing it | |
2290 | * @wait: poll table | |
2291 | * | |
2292 | * Called when the line discipline is asked to poll() for data or | |
2293 | * for special events. This code is not serialized with respect to | |
2294 | * other events save open/close. | |
2295 | * | |
2296 | * This code must be sure never to sleep through a hangup. | |
2297 | * Called without the kernel lock held - fine | |
2298 | */ | |
2299 | ||
2300 | static unsigned int gsmld_poll(struct tty_struct *tty, struct file *file, | |
2301 | poll_table *wait) | |
2302 | { | |
2303 | unsigned int mask = 0; | |
2304 | struct gsm_mux *gsm = tty->disc_data; | |
2305 | ||
2306 | poll_wait(file, &tty->read_wait, wait); | |
2307 | poll_wait(file, &tty->write_wait, wait); | |
2308 | if (tty_hung_up_p(file)) | |
2309 | mask |= POLLHUP; | |
2310 | if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0) | |
2311 | mask |= POLLOUT | POLLWRNORM; | |
2312 | if (gsm->dead) | |
2313 | mask |= POLLHUP; | |
2314 | return mask; | |
2315 | } | |
2316 | ||
2317 | static int gsmld_config(struct tty_struct *tty, struct gsm_mux *gsm, | |
2318 | struct gsm_config *c) | |
2319 | { | |
2320 | int need_close = 0; | |
2321 | int need_restart = 0; | |
2322 | ||
2323 | /* Stuff we don't support yet - UI or I frame transport, windowing */ | |
2324 | if ((c->adaption !=1 && c->adaption != 2) || c->k) | |
2325 | return -EOPNOTSUPP; | |
2326 | /* Check the MRU/MTU range looks sane */ | |
2327 | if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8) | |
2328 | return -EINVAL; | |
2329 | if (c->n2 < 3) | |
2330 | return -EINVAL; | |
2331 | if (c->encapsulation > 1) /* Basic, advanced, no I */ | |
2332 | return -EINVAL; | |
2333 | if (c->initiator > 1) | |
2334 | return -EINVAL; | |
2335 | if (c->i == 0 || c->i > 2) /* UIH and UI only */ | |
2336 | return -EINVAL; | |
2337 | /* | |
2338 | * See what is needed for reconfiguration | |
2339 | */ | |
2340 | ||
2341 | /* Timing fields */ | |
2342 | if (c->t1 != 0 && c->t1 != gsm->t1) | |
2343 | need_restart = 1; | |
2344 | if (c->t2 != 0 && c->t2 != gsm->t2) | |
2345 | need_restart = 1; | |
2346 | if (c->encapsulation != gsm->encoding) | |
2347 | need_restart = 1; | |
2348 | if (c->adaption != gsm->adaption) | |
2349 | need_restart = 1; | |
2350 | /* Requires care */ | |
2351 | if (c->initiator != gsm->initiator) | |
2352 | need_close = 1; | |
2353 | if (c->mru != gsm->mru) | |
2354 | need_restart = 1; | |
2355 | if (c->mtu != gsm->mtu) | |
2356 | need_restart = 1; | |
2357 | ||
2358 | /* | |
2359 | * Close down what is needed, restart and initiate the new | |
2360 | * configuration | |
2361 | */ | |
2362 | ||
2363 | if (need_close || need_restart) { | |
2364 | gsm_dlci_begin_close(gsm->dlci[0]); | |
2365 | /* This will timeout if the link is down due to N2 expiring */ | |
2366 | wait_event_interruptible(gsm->event, | |
2367 | gsm->dlci[0]->state == DLCI_CLOSED); | |
2368 | if (signal_pending(current)) | |
2369 | return -EINTR; | |
2370 | } | |
2371 | if (need_restart) | |
2372 | gsm_cleanup_mux(gsm); | |
2373 | ||
2374 | gsm->initiator = c->initiator; | |
2375 | gsm->mru = c->mru; | |
2376 | gsm->encoding = c->encapsulation; | |
2377 | gsm->adaption = c->adaption; | |
2378 | ||
2379 | if (c->i == 1) | |
2380 | gsm->ftype = UIH; | |
2381 | else if (c->i == 2) | |
2382 | gsm->ftype = UI; | |
2383 | ||
2384 | if (c->t1) | |
2385 | gsm->t1 = c->t1; | |
2386 | if (c->t2) | |
2387 | gsm->t2 = c->t2; | |
2388 | ||
2389 | /* FIXME: We need to separate activation/deactivation from adding | |
2390 | and removing from the mux array */ | |
2391 | if (need_restart) | |
2392 | gsm_activate_mux(gsm); | |
2393 | if (gsm->initiator && need_close) | |
2394 | gsm_dlci_begin_open(gsm->dlci[0]); | |
2395 | return 0; | |
2396 | } | |
2397 | ||
2398 | static int gsmld_ioctl(struct tty_struct *tty, struct file *file, | |
2399 | unsigned int cmd, unsigned long arg) | |
2400 | { | |
2401 | struct gsm_config c; | |
2402 | struct gsm_mux *gsm = tty->disc_data; | |
2403 | ||
2404 | switch (cmd) { | |
2405 | case GSMIOC_GETCONF: | |
2406 | memset(&c, 0, sizeof(c)); | |
2407 | c.adaption = gsm->adaption; | |
2408 | c.encapsulation = gsm->encoding; | |
2409 | c.initiator = gsm->initiator; | |
2410 | c.t1 = gsm->t1; | |
2411 | c.t2 = gsm->t2; | |
2412 | c.t3 = 0; /* Not supported */ | |
2413 | c.n2 = gsm->n2; | |
2414 | if (gsm->ftype == UIH) | |
2415 | c.i = 1; | |
2416 | else | |
2417 | c.i = 2; | |
2418 | printk("Ftype %d i %d\n", gsm->ftype, c.i); | |
2419 | c.mru = gsm->mru; | |
2420 | c.mtu = gsm->mtu; | |
2421 | c.k = 0; | |
2422 | if (copy_to_user((void *)arg, &c, sizeof(c))) | |
2423 | return -EFAULT; | |
2424 | return 0; | |
2425 | case GSMIOC_SETCONF: | |
2426 | if (copy_from_user(&c, (void *)arg, sizeof(c))) | |
2427 | return -EFAULT; | |
2428 | return gsmld_config(tty, gsm, &c); | |
2429 | default: | |
2430 | return n_tty_ioctl_helper(tty, file, cmd, arg); | |
2431 | } | |
2432 | } | |
2433 | ||
2434 | ||
2435 | /* Line discipline for real tty */ | |
2436 | struct tty_ldisc_ops tty_ldisc_packet = { | |
2437 | .owner = THIS_MODULE, | |
2438 | .magic = TTY_LDISC_MAGIC, | |
2439 | .name = "n_gsm", | |
2440 | .open = gsmld_open, | |
2441 | .close = gsmld_close, | |
2442 | .flush_buffer = gsmld_flush_buffer, | |
2443 | .chars_in_buffer = gsmld_chars_in_buffer, | |
2444 | .read = gsmld_read, | |
2445 | .write = gsmld_write, | |
2446 | .ioctl = gsmld_ioctl, | |
2447 | .poll = gsmld_poll, | |
2448 | .receive_buf = gsmld_receive_buf, | |
2449 | .write_wakeup = gsmld_write_wakeup | |
2450 | }; | |
2451 | ||
2452 | /* | |
2453 | * Virtual tty side | |
2454 | */ | |
2455 | ||
2456 | #define TX_SIZE 512 | |
2457 | ||
2458 | static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk) | |
2459 | { | |
2460 | u8 modembits[5]; | |
2461 | struct gsm_control *ctrl; | |
2462 | int len = 2; | |
2463 | ||
2464 | if (brk) | |
2465 | len++; | |
2466 | ||
2467 | modembits[0] = len << 1 | EA; /* Data bytes */ | |
2468 | modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */ | |
2469 | modembits[2] = gsm_encode_modem(dlci) << 1 | EA; | |
2470 | if (brk) | |
2471 | modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */ | |
2472 | ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1); | |
2473 | if (ctrl == NULL) | |
2474 | return -ENOMEM; | |
2475 | return gsm_control_wait(dlci->gsm, ctrl); | |
2476 | } | |
2477 | ||
2478 | static int gsm_carrier_raised(struct tty_port *port) | |
2479 | { | |
2480 | struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); | |
2481 | /* Not yet open so no carrier info */ | |
2482 | if (dlci->state != DLCI_OPEN) | |
2483 | return 0; | |
2484 | if (debug & 2) | |
2485 | return 1; | |
2486 | return dlci->modem_rx & TIOCM_CD; | |
2487 | } | |
2488 | ||
2489 | static void gsm_dtr_rts(struct tty_port *port, int onoff) | |
2490 | { | |
2491 | struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); | |
2492 | unsigned int modem_tx = dlci->modem_tx; | |
2493 | if (onoff) | |
2494 | modem_tx |= TIOCM_DTR | TIOCM_RTS; | |
2495 | else | |
2496 | modem_tx &= ~(TIOCM_DTR | TIOCM_RTS); | |
2497 | if (modem_tx != dlci->modem_tx) { | |
2498 | dlci->modem_tx = modem_tx; | |
2499 | gsmtty_modem_update(dlci, 0); | |
2500 | } | |
2501 | } | |
2502 | ||
2503 | static const struct tty_port_operations gsm_port_ops = { | |
2504 | .carrier_raised = gsm_carrier_raised, | |
2505 | .dtr_rts = gsm_dtr_rts, | |
2506 | }; | |
2507 | ||
2508 | ||
2509 | static int gsmtty_open(struct tty_struct *tty, struct file *filp) | |
2510 | { | |
2511 | struct gsm_mux *gsm; | |
2512 | struct gsm_dlci *dlci; | |
2513 | struct tty_port *port; | |
2514 | unsigned int line = tty->index; | |
2515 | unsigned int mux = line >> 6; | |
2516 | ||
2517 | line = line & 0x3F; | |
2518 | ||
2519 | if (mux >= MAX_MUX) | |
2520 | return -ENXIO; | |
2521 | /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */ | |
2522 | if (gsm_mux[mux] == NULL) | |
2523 | return -EUNATCH; | |
2524 | if (line == 0 || line > 61) /* 62/63 reserved */ | |
2525 | return -ECHRNG; | |
2526 | gsm = gsm_mux[mux]; | |
2527 | if (gsm->dead) | |
2528 | return -EL2HLT; | |
2529 | dlci = gsm->dlci[line]; | |
2530 | if (dlci == NULL) | |
2531 | dlci = gsm_dlci_alloc(gsm, line); | |
2532 | if (dlci == NULL) | |
2533 | return -ENOMEM; | |
2534 | port = &dlci->port; | |
2535 | port->count++; | |
2536 | tty->driver_data = dlci; | |
2537 | tty_port_tty_set(port, tty); | |
2538 | ||
2539 | dlci->modem_rx = 0; | |
2540 | /* We could in theory open and close before we wait - eg if we get | |
2541 | a DM straight back. This is ok as that will have caused a hangup */ | |
2542 | set_bit(ASYNCB_INITIALIZED, &port->flags); | |
2543 | /* Start sending off SABM messages */ | |
2544 | gsm_dlci_begin_open(dlci); | |
2545 | /* And wait for virtual carrier */ | |
2546 | return tty_port_block_til_ready(port, tty, filp); | |
2547 | } | |
2548 | ||
2549 | static void gsmtty_close(struct tty_struct *tty, struct file *filp) | |
2550 | { | |
2551 | struct gsm_dlci *dlci = tty->driver_data; | |
2552 | if (dlci == NULL) | |
2553 | return; | |
2554 | if (tty_port_close_start(&dlci->port, tty, filp) == 0) | |
2555 | return; | |
2556 | gsm_dlci_begin_close(dlci); | |
2557 | tty_port_close_end(&dlci->port, tty); | |
2558 | tty_port_tty_set(&dlci->port, NULL); | |
2559 | } | |
2560 | ||
2561 | static void gsmtty_hangup(struct tty_struct *tty) | |
2562 | { | |
2563 | struct gsm_dlci *dlci = tty->driver_data; | |
2564 | tty_port_hangup(&dlci->port); | |
2565 | gsm_dlci_begin_close(dlci); | |
2566 | } | |
2567 | ||
2568 | static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf, | |
2569 | int len) | |
2570 | { | |
2571 | struct gsm_dlci *dlci = tty->driver_data; | |
2572 | /* Stuff the bytes into the fifo queue */ | |
2573 | int sent = kfifo_in_locked(dlci->fifo, buf, len, &dlci->lock); | |
2574 | /* Need to kick the channel */ | |
2575 | gsm_dlci_data_kick(dlci); | |
2576 | return sent; | |
2577 | } | |
2578 | ||
2579 | static int gsmtty_write_room(struct tty_struct *tty) | |
2580 | { | |
2581 | struct gsm_dlci *dlci = tty->driver_data; | |
2582 | return TX_SIZE - kfifo_len(dlci->fifo); | |
2583 | } | |
2584 | ||
2585 | static int gsmtty_chars_in_buffer(struct tty_struct *tty) | |
2586 | { | |
2587 | struct gsm_dlci *dlci = tty->driver_data; | |
2588 | return kfifo_len(dlci->fifo); | |
2589 | } | |
2590 | ||
2591 | static void gsmtty_flush_buffer(struct tty_struct *tty) | |
2592 | { | |
2593 | struct gsm_dlci *dlci = tty->driver_data; | |
2594 | /* Caution needed: If we implement reliable transport classes | |
2595 | then the data being transmitted can't simply be junked once | |
2596 | it has first hit the stack. Until then we can just blow it | |
2597 | away */ | |
2598 | kfifo_reset(dlci->fifo); | |
2599 | /* Need to unhook this DLCI from the transmit queue logic */ | |
2600 | } | |
2601 | ||
2602 | static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout) | |
2603 | { | |
2604 | /* The FIFO handles the queue so the kernel will do the right | |
2605 | thing waiting on chars_in_buffer before calling us. No work | |
2606 | to do here */ | |
2607 | } | |
2608 | ||
2609 | static int gsmtty_tiocmget(struct tty_struct *tty, struct file *filp) | |
2610 | { | |
2611 | struct gsm_dlci *dlci = tty->driver_data; | |
2612 | return dlci->modem_rx; | |
2613 | } | |
2614 | ||
2615 | static int gsmtty_tiocmset(struct tty_struct *tty, struct file *filp, | |
2616 | unsigned int set, unsigned int clear) | |
2617 | { | |
2618 | struct gsm_dlci *dlci = tty->driver_data; | |
2619 | unsigned int modem_tx = dlci->modem_tx; | |
2620 | ||
2621 | modem_tx &= clear; | |
2622 | modem_tx |= set; | |
2623 | ||
2624 | if (modem_tx != dlci->modem_tx) { | |
2625 | dlci->modem_tx = modem_tx; | |
2626 | return gsmtty_modem_update(dlci, 0); | |
2627 | } | |
2628 | return 0; | |
2629 | } | |
2630 | ||
2631 | ||
2632 | static int gsmtty_ioctl(struct tty_struct *tty, struct file *filp, | |
2633 | unsigned int cmd, unsigned long arg) | |
2634 | { | |
2635 | return -ENOIOCTLCMD; | |
2636 | } | |
2637 | ||
2638 | static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old) | |
2639 | { | |
2640 | /* For the moment its fixed. In actual fact the speed information | |
2641 | for the virtual channel can be propogated in both directions by | |
2642 | the RPN control message. This however rapidly gets nasty as we | |
2643 | then have to remap modem signals each way according to whether | |
2644 | our virtual cable is null modem etc .. */ | |
2645 | tty_termios_copy_hw(tty->termios, old); | |
2646 | } | |
2647 | ||
2648 | static void gsmtty_throttle(struct tty_struct *tty) | |
2649 | { | |
2650 | struct gsm_dlci *dlci = tty->driver_data; | |
2651 | if (tty->termios->c_cflag & CRTSCTS) | |
2652 | dlci->modem_tx &= ~TIOCM_DTR; | |
2653 | dlci->throttled = 1; | |
2654 | /* Send an MSC with DTR cleared */ | |
2655 | gsmtty_modem_update(dlci, 0); | |
2656 | } | |
2657 | ||
2658 | static void gsmtty_unthrottle(struct tty_struct *tty) | |
2659 | { | |
2660 | struct gsm_dlci *dlci = tty->driver_data; | |
2661 | if (tty->termios->c_cflag & CRTSCTS) | |
2662 | dlci->modem_tx |= TIOCM_DTR; | |
2663 | dlci->throttled = 0; | |
2664 | /* Send an MSC with DTR set */ | |
2665 | gsmtty_modem_update(dlci, 0); | |
2666 | } | |
2667 | ||
2668 | static int gsmtty_break_ctl(struct tty_struct *tty, int state) | |
2669 | { | |
2670 | struct gsm_dlci *dlci = tty->driver_data; | |
2671 | int encode = 0; /* Off */ | |
2672 | ||
2673 | if (state == -1) /* "On indefinitely" - we can't encode this | |
2674 | properly */ | |
2675 | encode = 0x0F; | |
2676 | else if (state > 0) { | |
2677 | encode = state / 200; /* mS to encoding */ | |
2678 | if (encode > 0x0F) | |
2679 | encode = 0x0F; /* Best effort */ | |
2680 | } | |
2681 | return gsmtty_modem_update(dlci, encode); | |
2682 | } | |
2683 | ||
2684 | static struct tty_driver *gsm_tty_driver; | |
2685 | ||
2686 | /* Virtual ttys for the demux */ | |
2687 | static const struct tty_operations gsmtty_ops = { | |
2688 | .open = gsmtty_open, | |
2689 | .close = gsmtty_close, | |
2690 | .write = gsmtty_write, | |
2691 | .write_room = gsmtty_write_room, | |
2692 | .chars_in_buffer = gsmtty_chars_in_buffer, | |
2693 | .flush_buffer = gsmtty_flush_buffer, | |
2694 | .ioctl = gsmtty_ioctl, | |
2695 | .throttle = gsmtty_throttle, | |
2696 | .unthrottle = gsmtty_unthrottle, | |
2697 | .set_termios = gsmtty_set_termios, | |
2698 | .hangup = gsmtty_hangup, | |
2699 | .wait_until_sent = gsmtty_wait_until_sent, | |
2700 | .tiocmget = gsmtty_tiocmget, | |
2701 | .tiocmset = gsmtty_tiocmset, | |
2702 | .break_ctl = gsmtty_break_ctl, | |
2703 | }; | |
2704 | ||
2705 | ||
2706 | ||
2707 | static int __init gsm_init(void) | |
2708 | { | |
2709 | /* Fill in our line protocol discipline, and register it */ | |
2710 | int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet); | |
2711 | if (status != 0) { | |
2712 | printk(KERN_ERR "n_gsm: can't register line discipline (err = %d)\n", status); | |
2713 | return status; | |
2714 | } | |
2715 | ||
2716 | gsm_tty_driver = alloc_tty_driver(256); | |
2717 | if (!gsm_tty_driver) { | |
2718 | tty_unregister_ldisc(N_GSM0710); | |
2719 | printk(KERN_ERR "gsm_init: tty allocation failed.\n"); | |
2720 | return -EINVAL; | |
2721 | } | |
2722 | gsm_tty_driver->owner = THIS_MODULE; | |
2723 | gsm_tty_driver->driver_name = "gsmtty"; | |
2724 | gsm_tty_driver->name = "gsmtty"; | |
2725 | gsm_tty_driver->major = 0; /* Dynamic */ | |
2726 | gsm_tty_driver->minor_start = 0; | |
2727 | gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL; | |
2728 | gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL; | |
2729 | gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV | |
2730 | | TTY_DRIVER_HARDWARE_BREAK; | |
2731 | gsm_tty_driver->init_termios = tty_std_termios; | |
2732 | /* Fixme */ | |
2733 | gsm_tty_driver->init_termios.c_lflag &= ~ECHO; | |
2734 | tty_set_operations(gsm_tty_driver, &gsmtty_ops); | |
2735 | ||
2736 | spin_lock_init(&gsm_mux_lock); | |
2737 | ||
2738 | if (tty_register_driver(gsm_tty_driver)) { | |
2739 | put_tty_driver(gsm_tty_driver); | |
2740 | tty_unregister_ldisc(N_GSM0710); | |
2741 | printk(KERN_ERR "gsm_init: tty registration failed.\n"); | |
2742 | return -EBUSY; | |
2743 | } | |
2744 | printk(KERN_INFO "gsm_init: loaded as %d,%d.\n", gsm_tty_driver->major, gsm_tty_driver->minor_start); | |
2745 | return 0; | |
2746 | } | |
2747 | ||
2748 | static void __exit gsm_exit(void) | |
2749 | { | |
2750 | int status = tty_unregister_ldisc(N_GSM0710); | |
2751 | if (status != 0) | |
2752 | printk(KERN_ERR "n_gsm: can't unregister line discipline (err = %d)\n", status); | |
2753 | tty_unregister_driver(gsm_tty_driver); | |
2754 | put_tty_driver(gsm_tty_driver); | |
2755 | printk(KERN_INFO "gsm_init: unloaded.\n"); | |
2756 | } | |
2757 | ||
2758 | module_init(gsm_init); | |
2759 | module_exit(gsm_exit); | |
2760 | ||
2761 | ||
2762 | MODULE_LICENSE("GPL"); | |
2763 | MODULE_ALIAS_LDISC(N_GSM0710); |