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-rw-r--r--drivers/tty/n_gsm.c2764
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diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
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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>
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
63static int debug;
64module_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
87struct 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
106struct 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
149struct 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
167struct 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 */
244static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */
245static 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
295static const struct tty_port_operations gsm_port_ops;
296
297/*
298 * CRC table for GSM 0710
299 */
300
301static 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
348static 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
363static 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
379static 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
396static 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
426static 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
505static 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
521static 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
546static 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
593static 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
607static 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
628static 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
653static 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
708static 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 & 127) << 1) | EA;
720 *--dp = (msg->len >> 6) & 0xfe;
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
763static 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
783static 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
833static 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
901static 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;
906
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)
922 break;
923 /* DLCI empty - try the next */
924 if (len == 0)
925 i++;
926 }
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
938static 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
966static 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
987static 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
1034static 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
1084static 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
1125static 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
1139static 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
1207static 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
1239static 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
1261static 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
1296static 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;
1304retry:
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
1332static 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
1358static 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
1385static 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
1408static 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
1443static 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
1465static 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
1487static 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
1535static 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
1573static 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 */
1613static 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
1641static 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;
1733invalid:
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
1747static 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
1802static 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
1880static 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
1896void 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}
1933EXPORT_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
1944int 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}
1979EXPORT_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 */
1988void gsm_free_mux(struct gsm_mux *gsm)
1989{
1990 kfree(gsm->txframe);
1991 kfree(gsm->buf);
1992 kfree(gsm);
1993}
1994EXPORT_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
2002struct 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}
2033EXPORT_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
2048static 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
2072static 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
2093static 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
2101static 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
2148static 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
2162static 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
2176static 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
2197static 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
2226static void gsmld_write_wakeup(struct tty_struct *tty)
2227{
2228 struct gsm_mux *gsm = tty->disc_data;
2229 unsigned long flags;
2230
2231 /* Queue poll */
2232 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2233 gsm_data_kick(gsm);
2234 if (gsm->tx_bytes < TX_THRESH_LO) {
2235 spin_lock_irqsave(&gsm->tx_lock, flags);
2236 gsm_dlci_data_sweep(gsm);
2237 spin_unlock_irqrestore(&gsm->tx_lock, flags);
2238 }
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
2256static 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
2276static 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
2300static 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
2317static 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 gsm->n2 = c->n2;
2379
2380 if (c->i == 1)
2381 gsm->ftype = UIH;
2382 else if (c->i == 2)
2383 gsm->ftype = UI;
2384
2385 if (c->t1)
2386 gsm->t1 = c->t1;
2387 if (c->t2)
2388 gsm->t2 = c->t2;
2389
2390 /* FIXME: We need to separate activation/deactivation from adding
2391 and removing from the mux array */
2392 if (need_restart)
2393 gsm_activate_mux(gsm);
2394 if (gsm->initiator && need_close)
2395 gsm_dlci_begin_open(gsm->dlci[0]);
2396 return 0;
2397}
2398
2399static int gsmld_ioctl(struct tty_struct *tty, struct file *file,
2400 unsigned int cmd, unsigned long arg)
2401{
2402 struct gsm_config c;
2403 struct gsm_mux *gsm = tty->disc_data;
2404
2405 switch (cmd) {
2406 case GSMIOC_GETCONF:
2407 memset(&c, 0, sizeof(c));
2408 c.adaption = gsm->adaption;
2409 c.encapsulation = gsm->encoding;
2410 c.initiator = gsm->initiator;
2411 c.t1 = gsm->t1;
2412 c.t2 = gsm->t2;
2413 c.t3 = 0; /* Not supported */
2414 c.n2 = gsm->n2;
2415 if (gsm->ftype == UIH)
2416 c.i = 1;
2417 else
2418 c.i = 2;
2419 printk("Ftype %d i %d\n", gsm->ftype, c.i);
2420 c.mru = gsm->mru;
2421 c.mtu = gsm->mtu;
2422 c.k = 0;
2423 if (copy_to_user((void *)arg, &c, sizeof(c)))
2424 return -EFAULT;
2425 return 0;
2426 case GSMIOC_SETCONF:
2427 if (copy_from_user(&c, (void *)arg, sizeof(c)))
2428 return -EFAULT;
2429 return gsmld_config(tty, gsm, &c);
2430 default:
2431 return n_tty_ioctl_helper(tty, file, cmd, arg);
2432 }
2433}
2434
2435
2436/* Line discipline for real tty */
2437struct tty_ldisc_ops tty_ldisc_packet = {
2438 .owner = THIS_MODULE,
2439 .magic = TTY_LDISC_MAGIC,
2440 .name = "n_gsm",
2441 .open = gsmld_open,
2442 .close = gsmld_close,
2443 .flush_buffer = gsmld_flush_buffer,
2444 .chars_in_buffer = gsmld_chars_in_buffer,
2445 .read = gsmld_read,
2446 .write = gsmld_write,
2447 .ioctl = gsmld_ioctl,
2448 .poll = gsmld_poll,
2449 .receive_buf = gsmld_receive_buf,
2450 .write_wakeup = gsmld_write_wakeup
2451};
2452
2453/*
2454 * Virtual tty side
2455 */
2456
2457#define TX_SIZE 512
2458
2459static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk)
2460{
2461 u8 modembits[5];
2462 struct gsm_control *ctrl;
2463 int len = 2;
2464
2465 if (brk)
2466 len++;
2467
2468 modembits[0] = len << 1 | EA; /* Data bytes */
2469 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */
2470 modembits[2] = gsm_encode_modem(dlci) << 1 | EA;
2471 if (brk)
2472 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */
2473 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1);
2474 if (ctrl == NULL)
2475 return -ENOMEM;
2476 return gsm_control_wait(dlci->gsm, ctrl);
2477}
2478
2479static int gsm_carrier_raised(struct tty_port *port)
2480{
2481 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2482 /* Not yet open so no carrier info */
2483 if (dlci->state != DLCI_OPEN)
2484 return 0;
2485 if (debug & 2)
2486 return 1;
2487 return dlci->modem_rx & TIOCM_CD;
2488}
2489
2490static void gsm_dtr_rts(struct tty_port *port, int onoff)
2491{
2492 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2493 unsigned int modem_tx = dlci->modem_tx;
2494 if (onoff)
2495 modem_tx |= TIOCM_DTR | TIOCM_RTS;
2496 else
2497 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
2498 if (modem_tx != dlci->modem_tx) {
2499 dlci->modem_tx = modem_tx;
2500 gsmtty_modem_update(dlci, 0);
2501 }
2502}
2503
2504static const struct tty_port_operations gsm_port_ops = {
2505 .carrier_raised = gsm_carrier_raised,
2506 .dtr_rts = gsm_dtr_rts,
2507};
2508
2509
2510static int gsmtty_open(struct tty_struct *tty, struct file *filp)
2511{
2512 struct gsm_mux *gsm;
2513 struct gsm_dlci *dlci;
2514 struct tty_port *port;
2515 unsigned int line = tty->index;
2516 unsigned int mux = line >> 6;
2517
2518 line = line & 0x3F;
2519
2520 if (mux >= MAX_MUX)
2521 return -ENXIO;
2522 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
2523 if (gsm_mux[mux] == NULL)
2524 return -EUNATCH;
2525 if (line == 0 || line > 61) /* 62/63 reserved */
2526 return -ECHRNG;
2527 gsm = gsm_mux[mux];
2528 if (gsm->dead)
2529 return -EL2HLT;
2530 dlci = gsm->dlci[line];
2531 if (dlci == NULL)
2532 dlci = gsm_dlci_alloc(gsm, line);
2533 if (dlci == NULL)
2534 return -ENOMEM;
2535 port = &dlci->port;
2536 port->count++;
2537 tty->driver_data = dlci;
2538 tty_port_tty_set(port, tty);
2539
2540 dlci->modem_rx = 0;
2541 /* We could in theory open and close before we wait - eg if we get
2542 a DM straight back. This is ok as that will have caused a hangup */
2543 set_bit(ASYNCB_INITIALIZED, &port->flags);
2544 /* Start sending off SABM messages */
2545 gsm_dlci_begin_open(dlci);
2546 /* And wait for virtual carrier */
2547 return tty_port_block_til_ready(port, tty, filp);
2548}
2549
2550static void gsmtty_close(struct tty_struct *tty, struct file *filp)
2551{
2552 struct gsm_dlci *dlci = tty->driver_data;
2553 if (dlci == NULL)
2554 return;
2555 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
2556 return;
2557 gsm_dlci_begin_close(dlci);
2558 tty_port_close_end(&dlci->port, tty);
2559 tty_port_tty_set(&dlci->port, NULL);
2560}
2561
2562static void gsmtty_hangup(struct tty_struct *tty)
2563{
2564 struct gsm_dlci *dlci = tty->driver_data;
2565 tty_port_hangup(&dlci->port);
2566 gsm_dlci_begin_close(dlci);
2567}
2568
2569static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf,
2570 int len)
2571{
2572 struct gsm_dlci *dlci = tty->driver_data;
2573 /* Stuff the bytes into the fifo queue */
2574 int sent = kfifo_in_locked(dlci->fifo, buf, len, &dlci->lock);
2575 /* Need to kick the channel */
2576 gsm_dlci_data_kick(dlci);
2577 return sent;
2578}
2579
2580static int gsmtty_write_room(struct tty_struct *tty)
2581{
2582 struct gsm_dlci *dlci = tty->driver_data;
2583 return TX_SIZE - kfifo_len(dlci->fifo);
2584}
2585
2586static int gsmtty_chars_in_buffer(struct tty_struct *tty)
2587{
2588 struct gsm_dlci *dlci = tty->driver_data;
2589 return kfifo_len(dlci->fifo);
2590}
2591
2592static void gsmtty_flush_buffer(struct tty_struct *tty)
2593{
2594 struct gsm_dlci *dlci = tty->driver_data;
2595 /* Caution needed: If we implement reliable transport classes
2596 then the data being transmitted can't simply be junked once
2597 it has first hit the stack. Until then we can just blow it
2598 away */
2599 kfifo_reset(dlci->fifo);
2600 /* Need to unhook this DLCI from the transmit queue logic */
2601}
2602
2603static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
2604{
2605 /* The FIFO handles the queue so the kernel will do the right
2606 thing waiting on chars_in_buffer before calling us. No work
2607 to do here */
2608}
2609
2610static int gsmtty_tiocmget(struct tty_struct *tty, struct file *filp)
2611{
2612 struct gsm_dlci *dlci = tty->driver_data;
2613 return dlci->modem_rx;
2614}
2615
2616static int gsmtty_tiocmset(struct tty_struct *tty, struct file *filp,
2617 unsigned int set, unsigned int clear)
2618{
2619 struct gsm_dlci *dlci = tty->driver_data;
2620 unsigned int modem_tx = dlci->modem_tx;
2621
2622 modem_tx &= clear;
2623 modem_tx |= set;
2624
2625 if (modem_tx != dlci->modem_tx) {
2626 dlci->modem_tx = modem_tx;
2627 return gsmtty_modem_update(dlci, 0);
2628 }
2629 return 0;
2630}
2631
2632
2633static int gsmtty_ioctl(struct tty_struct *tty, struct file *filp,
2634 unsigned int cmd, unsigned long arg)
2635{
2636 return -ENOIOCTLCMD;
2637}
2638
2639static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old)
2640{
2641 /* For the moment its fixed. In actual fact the speed information
2642 for the virtual channel can be propogated in both directions by
2643 the RPN control message. This however rapidly gets nasty as we
2644 then have to remap modem signals each way according to whether
2645 our virtual cable is null modem etc .. */
2646 tty_termios_copy_hw(tty->termios, old);
2647}
2648
2649static void gsmtty_throttle(struct tty_struct *tty)
2650{
2651 struct gsm_dlci *dlci = tty->driver_data;
2652 if (tty->termios->c_cflag & CRTSCTS)
2653 dlci->modem_tx &= ~TIOCM_DTR;
2654 dlci->throttled = 1;
2655 /* Send an MSC with DTR cleared */
2656 gsmtty_modem_update(dlci, 0);
2657}
2658
2659static void gsmtty_unthrottle(struct tty_struct *tty)
2660{
2661 struct gsm_dlci *dlci = tty->driver_data;
2662 if (tty->termios->c_cflag & CRTSCTS)
2663 dlci->modem_tx |= TIOCM_DTR;
2664 dlci->throttled = 0;
2665 /* Send an MSC with DTR set */
2666 gsmtty_modem_update(dlci, 0);
2667}
2668
2669static int gsmtty_break_ctl(struct tty_struct *tty, int state)
2670{
2671 struct gsm_dlci *dlci = tty->driver_data;
2672 int encode = 0; /* Off */
2673
2674 if (state == -1) /* "On indefinitely" - we can't encode this
2675 properly */
2676 encode = 0x0F;
2677 else if (state > 0) {
2678 encode = state / 200; /* mS to encoding */
2679 if (encode > 0x0F)
2680 encode = 0x0F; /* Best effort */
2681 }
2682 return gsmtty_modem_update(dlci, encode);
2683}
2684
2685static struct tty_driver *gsm_tty_driver;
2686
2687/* Virtual ttys for the demux */
2688static const struct tty_operations gsmtty_ops = {
2689 .open = gsmtty_open,
2690 .close = gsmtty_close,
2691 .write = gsmtty_write,
2692 .write_room = gsmtty_write_room,
2693 .chars_in_buffer = gsmtty_chars_in_buffer,
2694 .flush_buffer = gsmtty_flush_buffer,
2695 .ioctl = gsmtty_ioctl,
2696 .throttle = gsmtty_throttle,
2697 .unthrottle = gsmtty_unthrottle,
2698 .set_termios = gsmtty_set_termios,
2699 .hangup = gsmtty_hangup,
2700 .wait_until_sent = gsmtty_wait_until_sent,
2701 .tiocmget = gsmtty_tiocmget,
2702 .tiocmset = gsmtty_tiocmset,
2703 .break_ctl = gsmtty_break_ctl,
2704};
2705
2706
2707
2708static int __init gsm_init(void)
2709{
2710 /* Fill in our line protocol discipline, and register it */
2711 int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet);
2712 if (status != 0) {
2713 printk(KERN_ERR "n_gsm: can't register line discipline (err = %d)\n", status);
2714 return status;
2715 }
2716
2717 gsm_tty_driver = alloc_tty_driver(256);
2718 if (!gsm_tty_driver) {
2719 tty_unregister_ldisc(N_GSM0710);
2720 printk(KERN_ERR "gsm_init: tty allocation failed.\n");
2721 return -EINVAL;
2722 }
2723 gsm_tty_driver->owner = THIS_MODULE;
2724 gsm_tty_driver->driver_name = "gsmtty";
2725 gsm_tty_driver->name = "gsmtty";
2726 gsm_tty_driver->major = 0; /* Dynamic */
2727 gsm_tty_driver->minor_start = 0;
2728 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
2729 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
2730 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV
2731 | TTY_DRIVER_HARDWARE_BREAK;
2732 gsm_tty_driver->init_termios = tty_std_termios;
2733 /* Fixme */
2734 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
2735 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
2736
2737 spin_lock_init(&gsm_mux_lock);
2738
2739 if (tty_register_driver(gsm_tty_driver)) {
2740 put_tty_driver(gsm_tty_driver);
2741 tty_unregister_ldisc(N_GSM0710);
2742 printk(KERN_ERR "gsm_init: tty registration failed.\n");
2743 return -EBUSY;
2744 }
2745 printk(KERN_INFO "gsm_init: loaded as %d,%d.\n", gsm_tty_driver->major, gsm_tty_driver->minor_start);
2746 return 0;
2747}
2748
2749static void __exit gsm_exit(void)
2750{
2751 int status = tty_unregister_ldisc(N_GSM0710);
2752 if (status != 0)
2753 printk(KERN_ERR "n_gsm: can't unregister line discipline (err = %d)\n", status);
2754 tty_unregister_driver(gsm_tty_driver);
2755 put_tty_driver(gsm_tty_driver);
2756 printk(KERN_INFO "gsm_init: unloaded.\n");
2757}
2758
2759module_init(gsm_init);
2760module_exit(gsm_exit);
2761
2762
2763MODULE_LICENSE("GPL");
2764MODULE_ALIAS_LDISC(N_GSM0710);
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-23 04:34:09 -0500