Loading...
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * n_gsm.c GSM 0710 tty multiplexor
4 * Copyright (c) 2009/10 Intel Corporation
5 *
6 * * THIS IS A DEVELOPMENT SNAPSHOT IT IS NOT A FINAL RELEASE *
7 *
8 * TO DO:
9 * Mostly done: ioctls for setting modes/timing
10 * Partly done: hooks so you can pull off frames to non tty devs
11 * Restart DLCI 0 when it closes ?
12 * Improve the tx engine
13 * Resolve tx side locking by adding a queue_head and routing
14 * all control traffic via it
15 * General tidy/document
16 * Review the locking/move to refcounts more (mux now moved to an
17 * alloc/free model ready)
18 * Use newest tty open/close port helpers and install hooks
19 * What to do about power functions ?
20 * Termios setting and negotiation
21 * Do we need a 'which mux are you' ioctl to correlate mux and tty sets
22 *
23 */
24
25#include <linux/types.h>
26#include <linux/major.h>
27#include <linux/errno.h>
28#include <linux/signal.h>
29#include <linux/fcntl.h>
30#include <linux/sched/signal.h>
31#include <linux/interrupt.h>
32#include <linux/tty.h>
33#include <linux/ctype.h>
34#include <linux/mm.h>
35#include <linux/string.h>
36#include <linux/slab.h>
37#include <linux/poll.h>
38#include <linux/bitops.h>
39#include <linux/file.h>
40#include <linux/uaccess.h>
41#include <linux/module.h>
42#include <linux/timer.h>
43#include <linux/tty_flip.h>
44#include <linux/tty_driver.h>
45#include <linux/serial.h>
46#include <linux/kfifo.h>
47#include <linux/skbuff.h>
48#include <net/arp.h>
49#include <linux/ip.h>
50#include <linux/netdevice.h>
51#include <linux/etherdevice.h>
52#include <linux/gsmmux.h>
53
54static int debug;
55module_param(debug, int, 0600);
56
57/* Defaults: these are from the specification */
58
59#define T1 10 /* 100mS */
60#define T2 34 /* 333mS */
61#define N2 3 /* Retry 3 times */
62
63/* Use long timers for testing at low speed with debug on */
64#ifdef DEBUG_TIMING
65#define T1 100
66#define T2 200
67#endif
68
69/*
70 * Semi-arbitrary buffer size limits. 0710 is normally run with 32-64 byte
71 * limits so this is plenty
72 */
73#define MAX_MRU 1500
74#define MAX_MTU 1500
75#define GSM_NET_TX_TIMEOUT (HZ*10)
76
77/**
78 * struct gsm_mux_net - network interface
79 * @struct gsm_dlci* dlci
80 *
81 * Created when net interface is initialized.
82 **/
83struct gsm_mux_net {
84 struct kref ref;
85 struct gsm_dlci *dlci;
86};
87
88/*
89 * Each block of data we have queued to go out is in the form of
90 * a gsm_msg which holds everything we need in a link layer independent
91 * format
92 */
93
94struct gsm_msg {
95 struct list_head list;
96 u8 addr; /* DLCI address + flags */
97 u8 ctrl; /* Control byte + flags */
98 unsigned int len; /* Length of data block (can be zero) */
99 unsigned char *data; /* Points into buffer but not at the start */
100 unsigned char buffer[0];
101};
102
103/*
104 * Each active data link has a gsm_dlci structure associated which ties
105 * the link layer to an optional tty (if the tty side is open). To avoid
106 * complexity right now these are only ever freed up when the mux is
107 * shut down.
108 *
109 * At the moment we don't free DLCI objects until the mux is torn down
110 * this avoid object life time issues but might be worth review later.
111 */
112
113struct gsm_dlci {
114 struct gsm_mux *gsm;
115 int addr;
116 int state;
117#define DLCI_CLOSED 0
118#define DLCI_OPENING 1 /* Sending SABM not seen UA */
119#define DLCI_OPEN 2 /* SABM/UA complete */
120#define DLCI_CLOSING 3 /* Sending DISC not seen UA/DM */
121 struct mutex mutex;
122
123 /* Link layer */
124 int mode;
125#define DLCI_MODE_ABM 0 /* Normal Asynchronous Balanced Mode */
126#define DLCI_MODE_ADM 1 /* Asynchronous Disconnected Mode */
127 spinlock_t lock; /* Protects the internal state */
128 struct timer_list t1; /* Retransmit timer for SABM and UA */
129 int retries;
130 /* Uplink tty if active */
131 struct tty_port port; /* The tty bound to this DLCI if there is one */
132 struct kfifo *fifo; /* Queue fifo for the DLCI */
133 struct kfifo _fifo; /* For new fifo API porting only */
134 int adaption; /* Adaption layer in use */
135 int prev_adaption;
136 u32 modem_rx; /* Our incoming virtual modem lines */
137 u32 modem_tx; /* Our outgoing modem lines */
138 int dead; /* Refuse re-open */
139 /* Flow control */
140 int throttled; /* Private copy of throttle state */
141 int constipated; /* Throttle status for outgoing */
142 /* Packetised I/O */
143 struct sk_buff *skb; /* Frame being sent */
144 struct sk_buff_head skb_list; /* Queued frames */
145 /* Data handling callback */
146 void (*data)(struct gsm_dlci *dlci, const u8 *data, int len);
147 void (*prev_data)(struct gsm_dlci *dlci, const u8 *data, int len);
148 struct net_device *net; /* network interface, if created */
149};
150
151/* DLCI 0, 62/63 are special or reserved see gsmtty_open */
152
153#define NUM_DLCI 64
154
155/*
156 * DLCI 0 is used to pass control blocks out of band of the data
157 * flow (and with a higher link priority). One command can be outstanding
158 * at a time and we use this structure to manage them. They are created
159 * and destroyed by the user context, and updated by the receive paths
160 * and timers
161 */
162
163struct gsm_control {
164 u8 cmd; /* Command we are issuing */
165 u8 *data; /* Data for the command in case we retransmit */
166 int len; /* Length of block for retransmission */
167 int done; /* Done flag */
168 int error; /* Error if any */
169};
170
171/*
172 * Each GSM mux we have is represented by this structure. If we are
173 * operating as an ldisc then we use this structure as our ldisc
174 * state. We need to sort out lifetimes and locking with respect
175 * to the gsm mux array. For now we don't free DLCI objects that
176 * have been instantiated until the mux itself is terminated.
177 *
178 * To consider further: tty open versus mux shutdown.
179 */
180
181struct gsm_mux {
182 struct tty_struct *tty; /* The tty our ldisc is bound to */
183 spinlock_t lock;
184 struct mutex mutex;
185 unsigned int num;
186 struct kref ref;
187
188 /* Events on the GSM channel */
189 wait_queue_head_t event;
190
191 /* Bits for GSM mode decoding */
192
193 /* Framing Layer */
194 unsigned char *buf;
195 int state;
196#define GSM_SEARCH 0
197#define GSM_START 1
198#define GSM_ADDRESS 2
199#define GSM_CONTROL 3
200#define GSM_LEN 4
201#define GSM_DATA 5
202#define GSM_FCS 6
203#define GSM_OVERRUN 7
204#define GSM_LEN0 8
205#define GSM_LEN1 9
206#define GSM_SSOF 10
207 unsigned int len;
208 unsigned int address;
209 unsigned int count;
210 int escape;
211 int encoding;
212 u8 control;
213 u8 fcs;
214 u8 received_fcs;
215 u8 *txframe; /* TX framing buffer */
216
217 /* Methods for the receiver side */
218 void (*receive)(struct gsm_mux *gsm, u8 ch);
219 void (*error)(struct gsm_mux *gsm, u8 ch, u8 flag);
220 /* And transmit side */
221 int (*output)(struct gsm_mux *mux, u8 *data, int len);
222
223 /* Link Layer */
224 unsigned int mru;
225 unsigned int mtu;
226 int initiator; /* Did we initiate connection */
227 int dead; /* Has the mux been shut down */
228 struct gsm_dlci *dlci[NUM_DLCI];
229 int constipated; /* Asked by remote to shut up */
230
231 spinlock_t tx_lock;
232 unsigned int tx_bytes; /* TX data outstanding */
233#define TX_THRESH_HI 8192
234#define TX_THRESH_LO 2048
235 struct list_head tx_list; /* Pending data packets */
236
237 /* Control messages */
238 struct timer_list t2_timer; /* Retransmit timer for commands */
239 int cretries; /* Command retry counter */
240 struct gsm_control *pending_cmd;/* Our current pending command */
241 spinlock_t control_lock; /* Protects the pending command */
242
243 /* Configuration */
244 int adaption; /* 1 or 2 supported */
245 u8 ftype; /* UI or UIH */
246 int t1, t2; /* Timers in 1/100th of a sec */
247 int n2; /* Retry count */
248
249 /* Statistics (not currently exposed) */
250 unsigned long bad_fcs;
251 unsigned long malformed;
252 unsigned long io_error;
253 unsigned long bad_size;
254 unsigned long unsupported;
255};
256
257
258/*
259 * Mux objects - needed so that we can translate a tty index into the
260 * relevant mux and DLCI.
261 */
262
263#define MAX_MUX 4 /* 256 minors */
264static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */
265static spinlock_t gsm_mux_lock;
266
267static struct tty_driver *gsm_tty_driver;
268
269/*
270 * This section of the driver logic implements the GSM encodings
271 * both the basic and the 'advanced'. Reliable transport is not
272 * supported.
273 */
274
275#define CR 0x02
276#define EA 0x01
277#define PF 0x10
278
279/* I is special: the rest are ..*/
280#define RR 0x01
281#define UI 0x03
282#define RNR 0x05
283#define REJ 0x09
284#define DM 0x0F
285#define SABM 0x2F
286#define DISC 0x43
287#define UA 0x63
288#define UIH 0xEF
289
290/* Channel commands */
291#define CMD_NSC 0x09
292#define CMD_TEST 0x11
293#define CMD_PSC 0x21
294#define CMD_RLS 0x29
295#define CMD_FCOFF 0x31
296#define CMD_PN 0x41
297#define CMD_RPN 0x49
298#define CMD_FCON 0x51
299#define CMD_CLD 0x61
300#define CMD_SNC 0x69
301#define CMD_MSC 0x71
302
303/* Virtual modem bits */
304#define MDM_FC 0x01
305#define MDM_RTC 0x02
306#define MDM_RTR 0x04
307#define MDM_IC 0x20
308#define MDM_DV 0x40
309
310#define GSM0_SOF 0xF9
311#define GSM1_SOF 0x7E
312#define GSM1_ESCAPE 0x7D
313#define GSM1_ESCAPE_BITS 0x20
314#define XON 0x11
315#define XOFF 0x13
316
317static const struct tty_port_operations gsm_port_ops;
318
319/*
320 * CRC table for GSM 0710
321 */
322
323static const u8 gsm_fcs8[256] = {
324 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75,
325 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B,
326 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69,
327 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67,
328 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D,
329 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43,
330 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51,
331 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F,
332 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05,
333 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B,
334 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19,
335 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17,
336 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D,
337 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33,
338 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21,
339 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F,
340 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95,
341 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B,
342 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89,
343 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87,
344 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD,
345 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3,
346 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1,
347 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF,
348 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5,
349 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB,
350 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9,
351 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7,
352 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD,
353 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3,
354 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1,
355 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF
356};
357
358#define INIT_FCS 0xFF
359#define GOOD_FCS 0xCF
360
361/**
362 * gsm_fcs_add - update FCS
363 * @fcs: Current FCS
364 * @c: Next data
365 *
366 * Update the FCS to include c. Uses the algorithm in the specification
367 * notes.
368 */
369
370static inline u8 gsm_fcs_add(u8 fcs, u8 c)
371{
372 return gsm_fcs8[fcs ^ c];
373}
374
375/**
376 * gsm_fcs_add_block - update FCS for a block
377 * @fcs: Current FCS
378 * @c: buffer of data
379 * @len: length of buffer
380 *
381 * Update the FCS to include c. Uses the algorithm in the specification
382 * notes.
383 */
384
385static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len)
386{
387 while (len--)
388 fcs = gsm_fcs8[fcs ^ *c++];
389 return fcs;
390}
391
392/**
393 * gsm_read_ea - read a byte into an EA
394 * @val: variable holding value
395 * c: byte going into the EA
396 *
397 * Processes one byte of an EA. Updates the passed variable
398 * and returns 1 if the EA is now completely read
399 */
400
401static int gsm_read_ea(unsigned int *val, u8 c)
402{
403 /* Add the next 7 bits into the value */
404 *val <<= 7;
405 *val |= c >> 1;
406 /* Was this the last byte of the EA 1 = yes*/
407 return c & EA;
408}
409
410/**
411 * gsm_encode_modem - encode modem data bits
412 * @dlci: DLCI to encode from
413 *
414 * Returns the correct GSM encoded modem status bits (6 bit field) for
415 * the current status of the DLCI and attached tty object
416 */
417
418static u8 gsm_encode_modem(const struct gsm_dlci *dlci)
419{
420 u8 modembits = 0;
421 /* FC is true flow control not modem bits */
422 if (dlci->throttled)
423 modembits |= MDM_FC;
424 if (dlci->modem_tx & TIOCM_DTR)
425 modembits |= MDM_RTC;
426 if (dlci->modem_tx & TIOCM_RTS)
427 modembits |= MDM_RTR;
428 if (dlci->modem_tx & TIOCM_RI)
429 modembits |= MDM_IC;
430 if (dlci->modem_tx & TIOCM_CD)
431 modembits |= MDM_DV;
432 return modembits;
433}
434
435/**
436 * gsm_print_packet - display a frame for debug
437 * @hdr: header to print before decode
438 * @addr: address EA from the frame
439 * @cr: C/R bit from the frame
440 * @control: control including PF bit
441 * @data: following data bytes
442 * @dlen: length of data
443 *
444 * Displays a packet in human readable format for debugging purposes. The
445 * style is based on amateur radio LAP-B dump display.
446 */
447
448static void gsm_print_packet(const char *hdr, int addr, int cr,
449 u8 control, const u8 *data, int dlen)
450{
451 if (!(debug & 1))
452 return;
453
454 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]);
455
456 switch (control & ~PF) {
457 case SABM:
458 pr_cont("SABM");
459 break;
460 case UA:
461 pr_cont("UA");
462 break;
463 case DISC:
464 pr_cont("DISC");
465 break;
466 case DM:
467 pr_cont("DM");
468 break;
469 case UI:
470 pr_cont("UI");
471 break;
472 case UIH:
473 pr_cont("UIH");
474 break;
475 default:
476 if (!(control & 0x01)) {
477 pr_cont("I N(S)%d N(R)%d",
478 (control & 0x0E) >> 1, (control & 0xE0) >> 5);
479 } else switch (control & 0x0F) {
480 case RR:
481 pr_cont("RR(%d)", (control & 0xE0) >> 5);
482 break;
483 case RNR:
484 pr_cont("RNR(%d)", (control & 0xE0) >> 5);
485 break;
486 case REJ:
487 pr_cont("REJ(%d)", (control & 0xE0) >> 5);
488 break;
489 default:
490 pr_cont("[%02X]", control);
491 }
492 }
493
494 if (control & PF)
495 pr_cont("(P)");
496 else
497 pr_cont("(F)");
498
499 if (dlen) {
500 int ct = 0;
501 while (dlen--) {
502 if (ct % 8 == 0) {
503 pr_cont("\n");
504 pr_debug(" ");
505 }
506 pr_cont("%02X ", *data++);
507 ct++;
508 }
509 }
510 pr_cont("\n");
511}
512
513
514/*
515 * Link level transmission side
516 */
517
518/**
519 * gsm_stuff_packet - bytestuff a packet
520 * @ibuf: input
521 * @obuf: output
522 * @len: length of input
523 *
524 * Expand a buffer by bytestuffing it. The worst case size change
525 * is doubling and the caller is responsible for handing out
526 * suitable sized buffers.
527 */
528
529static int gsm_stuff_frame(const u8 *input, u8 *output, int len)
530{
531 int olen = 0;
532 while (len--) {
533 if (*input == GSM1_SOF || *input == GSM1_ESCAPE
534 || *input == XON || *input == XOFF) {
535 *output++ = GSM1_ESCAPE;
536 *output++ = *input++ ^ GSM1_ESCAPE_BITS;
537 olen++;
538 } else
539 *output++ = *input++;
540 olen++;
541 }
542 return olen;
543}
544
545/**
546 * gsm_send - send a control frame
547 * @gsm: our GSM mux
548 * @addr: address for control frame
549 * @cr: command/response bit
550 * @control: control byte including PF bit
551 *
552 * Format up and transmit a control frame. These do not go via the
553 * queueing logic as they should be transmitted ahead of data when
554 * they are needed.
555 *
556 * FIXME: Lock versus data TX path
557 */
558
559static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control)
560{
561 int len;
562 u8 cbuf[10];
563 u8 ibuf[3];
564
565 switch (gsm->encoding) {
566 case 0:
567 cbuf[0] = GSM0_SOF;
568 cbuf[1] = (addr << 2) | (cr << 1) | EA;
569 cbuf[2] = control;
570 cbuf[3] = EA; /* Length of data = 0 */
571 cbuf[4] = 0xFF - gsm_fcs_add_block(INIT_FCS, cbuf + 1, 3);
572 cbuf[5] = GSM0_SOF;
573 len = 6;
574 break;
575 case 1:
576 case 2:
577 /* Control frame + packing (but not frame stuffing) in mode 1 */
578 ibuf[0] = (addr << 2) | (cr << 1) | EA;
579 ibuf[1] = control;
580 ibuf[2] = 0xFF - gsm_fcs_add_block(INIT_FCS, ibuf, 2);
581 /* Stuffing may double the size worst case */
582 len = gsm_stuff_frame(ibuf, cbuf + 1, 3);
583 /* Now add the SOF markers */
584 cbuf[0] = GSM1_SOF;
585 cbuf[len + 1] = GSM1_SOF;
586 /* FIXME: we can omit the lead one in many cases */
587 len += 2;
588 break;
589 default:
590 WARN_ON(1);
591 return;
592 }
593 gsm->output(gsm, cbuf, len);
594 gsm_print_packet("-->", addr, cr, control, NULL, 0);
595}
596
597/**
598 * gsm_response - send a control response
599 * @gsm: our GSM mux
600 * @addr: address for control frame
601 * @control: control byte including PF bit
602 *
603 * Format up and transmit a link level response frame.
604 */
605
606static inline void gsm_response(struct gsm_mux *gsm, int addr, int control)
607{
608 gsm_send(gsm, addr, 0, control);
609}
610
611/**
612 * gsm_command - send a control command
613 * @gsm: our GSM mux
614 * @addr: address for control frame
615 * @control: control byte including PF bit
616 *
617 * Format up and transmit a link level command frame.
618 */
619
620static inline void gsm_command(struct gsm_mux *gsm, int addr, int control)
621{
622 gsm_send(gsm, addr, 1, control);
623}
624
625/* Data transmission */
626
627#define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */
628
629/**
630 * gsm_data_alloc - allocate data frame
631 * @gsm: GSM mux
632 * @addr: DLCI address
633 * @len: length excluding header and FCS
634 * @ctrl: control byte
635 *
636 * Allocate a new data buffer for sending frames with data. Space is left
637 * at the front for header bytes but that is treated as an implementation
638 * detail and not for the high level code to use
639 */
640
641static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
642 u8 ctrl)
643{
644 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN,
645 GFP_ATOMIC);
646 if (m == NULL)
647 return NULL;
648 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */
649 m->len = len;
650 m->addr = addr;
651 m->ctrl = ctrl;
652 INIT_LIST_HEAD(&m->list);
653 return m;
654}
655
656/**
657 * gsm_data_kick - poke the queue
658 * @gsm: GSM Mux
659 *
660 * The tty device has called us to indicate that room has appeared in
661 * the transmit queue. Ram more data into the pipe if we have any
662 * If we have been flow-stopped by a CMD_FCOFF, then we can only
663 * send messages on DLCI0 until CMD_FCON
664 *
665 * FIXME: lock against link layer control transmissions
666 */
667
668static void gsm_data_kick(struct gsm_mux *gsm)
669{
670 struct gsm_msg *msg, *nmsg;
671 int len;
672 int skip_sof = 0;
673
674 list_for_each_entry_safe(msg, nmsg, &gsm->tx_list, list) {
675 if (gsm->constipated && msg->addr)
676 continue;
677 if (gsm->encoding != 0) {
678 gsm->txframe[0] = GSM1_SOF;
679 len = gsm_stuff_frame(msg->data,
680 gsm->txframe + 1, msg->len);
681 gsm->txframe[len + 1] = GSM1_SOF;
682 len += 2;
683 } else {
684 gsm->txframe[0] = GSM0_SOF;
685 memcpy(gsm->txframe + 1 , msg->data, msg->len);
686 gsm->txframe[msg->len + 1] = GSM0_SOF;
687 len = msg->len + 2;
688 }
689
690 if (debug & 4)
691 print_hex_dump_bytes("gsm_data_kick: ",
692 DUMP_PREFIX_OFFSET,
693 gsm->txframe, len);
694
695 if (gsm->output(gsm, gsm->txframe + skip_sof,
696 len - skip_sof) < 0)
697 break;
698 /* FIXME: Can eliminate one SOF in many more cases */
699 gsm->tx_bytes -= msg->len;
700 /* For a burst of frames skip the extra SOF within the
701 burst */
702 skip_sof = 1;
703
704 list_del(&msg->list);
705 kfree(msg);
706 }
707}
708
709/**
710 * __gsm_data_queue - queue a UI or UIH frame
711 * @dlci: DLCI sending the data
712 * @msg: message queued
713 *
714 * Add data to the transmit queue and try and get stuff moving
715 * out of the mux tty if not already doing so. The Caller must hold
716 * the gsm tx lock.
717 */
718
719static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
720{
721 struct gsm_mux *gsm = dlci->gsm;
722 u8 *dp = msg->data;
723 u8 *fcs = dp + msg->len;
724
725 /* Fill in the header */
726 if (gsm->encoding == 0) {
727 if (msg->len < 128)
728 *--dp = (msg->len << 1) | EA;
729 else {
730 *--dp = (msg->len >> 7); /* bits 7 - 15 */
731 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */
732 }
733 }
734
735 *--dp = msg->ctrl;
736 if (gsm->initiator)
737 *--dp = (msg->addr << 2) | 2 | EA;
738 else
739 *--dp = (msg->addr << 2) | EA;
740 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp);
741 /* Ugly protocol layering violation */
742 if (msg->ctrl == UI || msg->ctrl == (UI|PF))
743 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len);
744 *fcs = 0xFF - *fcs;
745
746 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl,
747 msg->data, msg->len);
748
749 /* Move the header back and adjust the length, also allow for the FCS
750 now tacked on the end */
751 msg->len += (msg->data - dp) + 1;
752 msg->data = dp;
753
754 /* Add to the actual output queue */
755 list_add_tail(&msg->list, &gsm->tx_list);
756 gsm->tx_bytes += msg->len;
757 gsm_data_kick(gsm);
758}
759
760/**
761 * gsm_data_queue - queue a UI or UIH frame
762 * @dlci: DLCI sending the data
763 * @msg: message queued
764 *
765 * Add data to the transmit queue and try and get stuff moving
766 * out of the mux tty if not already doing so. Take the
767 * the gsm tx lock and dlci lock.
768 */
769
770static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
771{
772 unsigned long flags;
773 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
774 __gsm_data_queue(dlci, msg);
775 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
776}
777
778/**
779 * gsm_dlci_data_output - try and push data out of a DLCI
780 * @gsm: mux
781 * @dlci: the DLCI to pull data from
782 *
783 * Pull data from a DLCI and send it into the transmit queue if there
784 * is data. Keep to the MRU of the mux. This path handles the usual tty
785 * interface which is a byte stream with optional modem data.
786 *
787 * Caller must hold the tx_lock of the mux.
788 */
789
790static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci)
791{
792 struct gsm_msg *msg;
793 u8 *dp;
794 int len, total_size, size;
795 int h = dlci->adaption - 1;
796
797 total_size = 0;
798 while (1) {
799 len = kfifo_len(dlci->fifo);
800 if (len == 0)
801 return total_size;
802
803 /* MTU/MRU count only the data bits */
804 if (len > gsm->mtu)
805 len = gsm->mtu;
806
807 size = len + h;
808
809 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
810 /* FIXME: need a timer or something to kick this so it can't
811 get stuck with no work outstanding and no buffer free */
812 if (msg == NULL)
813 return -ENOMEM;
814 dp = msg->data;
815 switch (dlci->adaption) {
816 case 1: /* Unstructured */
817 break;
818 case 2: /* Unstructed with modem bits.
819 Always one byte as we never send inline break data */
820 *dp++ = gsm_encode_modem(dlci);
821 break;
822 }
823 WARN_ON(kfifo_out_locked(dlci->fifo, dp , len, &dlci->lock) != len);
824 __gsm_data_queue(dlci, msg);
825 total_size += size;
826 }
827 /* Bytes of data we used up */
828 return total_size;
829}
830
831/**
832 * gsm_dlci_data_output_framed - try and push data out of a DLCI
833 * @gsm: mux
834 * @dlci: the DLCI to pull data from
835 *
836 * Pull data from a DLCI and send it into the transmit queue if there
837 * is data. Keep to the MRU of the mux. This path handles framed data
838 * queued as skbuffs to the DLCI.
839 *
840 * Caller must hold the tx_lock of the mux.
841 */
842
843static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
844 struct gsm_dlci *dlci)
845{
846 struct gsm_msg *msg;
847 u8 *dp;
848 int len, size;
849 int last = 0, first = 0;
850 int overhead = 0;
851
852 /* One byte per frame is used for B/F flags */
853 if (dlci->adaption == 4)
854 overhead = 1;
855
856 /* dlci->skb is locked by tx_lock */
857 if (dlci->skb == NULL) {
858 dlci->skb = skb_dequeue_tail(&dlci->skb_list);
859 if (dlci->skb == NULL)
860 return 0;
861 first = 1;
862 }
863 len = dlci->skb->len + overhead;
864
865 /* MTU/MRU count only the data bits */
866 if (len > gsm->mtu) {
867 if (dlci->adaption == 3) {
868 /* Over long frame, bin it */
869 dev_kfree_skb_any(dlci->skb);
870 dlci->skb = NULL;
871 return 0;
872 }
873 len = gsm->mtu;
874 } else
875 last = 1;
876
877 size = len + overhead;
878 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
879
880 /* FIXME: need a timer or something to kick this so it can't
881 get stuck with no work outstanding and no buffer free */
882 if (msg == NULL) {
883 skb_queue_tail(&dlci->skb_list, dlci->skb);
884 dlci->skb = NULL;
885 return -ENOMEM;
886 }
887 dp = msg->data;
888
889 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */
890 /* Flag byte to carry the start/end info */
891 *dp++ = last << 7 | first << 6 | 1; /* EA */
892 len--;
893 }
894 memcpy(dp, dlci->skb->data, len);
895 skb_pull(dlci->skb, len);
896 __gsm_data_queue(dlci, msg);
897 if (last) {
898 dev_kfree_skb_any(dlci->skb);
899 dlci->skb = NULL;
900 }
901 return size;
902}
903
904/**
905 * gsm_dlci_data_sweep - look for data to send
906 * @gsm: the GSM mux
907 *
908 * Sweep the GSM mux channels in priority order looking for ones with
909 * data to send. We could do with optimising this scan a bit. We aim
910 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit
911 * TX_THRESH_LO we get called again
912 *
913 * FIXME: We should round robin between groups and in theory you can
914 * renegotiate DLCI priorities with optional stuff. Needs optimising.
915 */
916
917static void gsm_dlci_data_sweep(struct gsm_mux *gsm)
918{
919 int len;
920 /* Priority ordering: We should do priority with RR of the groups */
921 int i = 1;
922
923 while (i < NUM_DLCI) {
924 struct gsm_dlci *dlci;
925
926 if (gsm->tx_bytes > TX_THRESH_HI)
927 break;
928 dlci = gsm->dlci[i];
929 if (dlci == NULL || dlci->constipated) {
930 i++;
931 continue;
932 }
933 if (dlci->adaption < 3 && !dlci->net)
934 len = gsm_dlci_data_output(gsm, dlci);
935 else
936 len = gsm_dlci_data_output_framed(gsm, dlci);
937 if (len < 0)
938 break;
939 /* DLCI empty - try the next */
940 if (len == 0)
941 i++;
942 }
943}
944
945/**
946 * gsm_dlci_data_kick - transmit if possible
947 * @dlci: DLCI to kick
948 *
949 * Transmit data from this DLCI if the queue is empty. We can't rely on
950 * a tty wakeup except when we filled the pipe so we need to fire off
951 * new data ourselves in other cases.
952 */
953
954static void gsm_dlci_data_kick(struct gsm_dlci *dlci)
955{
956 unsigned long flags;
957 int sweep;
958
959 if (dlci->constipated)
960 return;
961
962 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
963 /* If we have nothing running then we need to fire up */
964 sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO);
965 if (dlci->gsm->tx_bytes == 0) {
966 if (dlci->net)
967 gsm_dlci_data_output_framed(dlci->gsm, dlci);
968 else
969 gsm_dlci_data_output(dlci->gsm, dlci);
970 }
971 if (sweep)
972 gsm_dlci_data_sweep(dlci->gsm);
973 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
974}
975
976/*
977 * Control message processing
978 */
979
980
981/**
982 * gsm_control_reply - send a response frame to a control
983 * @gsm: gsm channel
984 * @cmd: the command to use
985 * @data: data to follow encoded info
986 * @dlen: length of data
987 *
988 * Encode up and queue a UI/UIH frame containing our response.
989 */
990
991static void gsm_control_reply(struct gsm_mux *gsm, int cmd, const u8 *data,
992 int dlen)
993{
994 struct gsm_msg *msg;
995 msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype);
996 if (msg == NULL)
997 return;
998 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */
999 msg->data[1] = (dlen << 1) | EA;
1000 memcpy(msg->data + 2, data, dlen);
1001 gsm_data_queue(gsm->dlci[0], msg);
1002}
1003
1004/**
1005 * gsm_process_modem - process received modem status
1006 * @tty: virtual tty bound to the DLCI
1007 * @dlci: DLCI to affect
1008 * @modem: modem bits (full EA)
1009 *
1010 * Used when a modem control message or line state inline in adaption
1011 * layer 2 is processed. Sort out the local modem state and throttles
1012 */
1013
1014static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
1015 u32 modem, int clen)
1016{
1017 int mlines = 0;
1018 u8 brk = 0;
1019 int fc;
1020
1021 /* The modem status command can either contain one octet (v.24 signals)
1022 or two octets (v.24 signals + break signals). The length field will
1023 either be 2 or 3 respectively. This is specified in section
1024 5.4.6.3.7 of the 27.010 mux spec. */
1025
1026 if (clen == 2)
1027 modem = modem & 0x7f;
1028 else {
1029 brk = modem & 0x7f;
1030 modem = (modem >> 7) & 0x7f;
1031 }
1032
1033 /* Flow control/ready to communicate */
1034 fc = (modem & MDM_FC) || !(modem & MDM_RTR);
1035 if (fc && !dlci->constipated) {
1036 /* Need to throttle our output on this device */
1037 dlci->constipated = 1;
1038 } else if (!fc && dlci->constipated) {
1039 dlci->constipated = 0;
1040 gsm_dlci_data_kick(dlci);
1041 }
1042
1043 /* Map modem bits */
1044 if (modem & MDM_RTC)
1045 mlines |= TIOCM_DSR | TIOCM_DTR;
1046 if (modem & MDM_RTR)
1047 mlines |= TIOCM_RTS | TIOCM_CTS;
1048 if (modem & MDM_IC)
1049 mlines |= TIOCM_RI;
1050 if (modem & MDM_DV)
1051 mlines |= TIOCM_CD;
1052
1053 /* Carrier drop -> hangup */
1054 if (tty) {
1055 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD))
1056 if (!C_CLOCAL(tty))
1057 tty_hangup(tty);
1058 }
1059 if (brk & 0x01)
1060 tty_insert_flip_char(&dlci->port, 0, TTY_BREAK);
1061 dlci->modem_rx = mlines;
1062}
1063
1064/**
1065 * gsm_control_modem - modem status received
1066 * @gsm: GSM channel
1067 * @data: data following command
1068 * @clen: command length
1069 *
1070 * We have received a modem status control message. This is used by
1071 * the GSM mux protocol to pass virtual modem line status and optionally
1072 * to indicate break signals. Unpack it, convert to Linux representation
1073 * and if need be stuff a break message down the tty.
1074 */
1075
1076static void gsm_control_modem(struct gsm_mux *gsm, const u8 *data, int clen)
1077{
1078 unsigned int addr = 0;
1079 unsigned int modem = 0;
1080 unsigned int brk = 0;
1081 struct gsm_dlci *dlci;
1082 int len = clen;
1083 const u8 *dp = data;
1084 struct tty_struct *tty;
1085
1086 while (gsm_read_ea(&addr, *dp++) == 0) {
1087 len--;
1088 if (len == 0)
1089 return;
1090 }
1091 /* Must be at least one byte following the EA */
1092 len--;
1093 if (len <= 0)
1094 return;
1095
1096 addr >>= 1;
1097 /* Closed port, or invalid ? */
1098 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1099 return;
1100 dlci = gsm->dlci[addr];
1101
1102 while (gsm_read_ea(&modem, *dp++) == 0) {
1103 len--;
1104 if (len == 0)
1105 return;
1106 }
1107 len--;
1108 if (len > 0) {
1109 while (gsm_read_ea(&brk, *dp++) == 0) {
1110 len--;
1111 if (len == 0)
1112 return;
1113 }
1114 modem <<= 7;
1115 modem |= (brk & 0x7f);
1116 }
1117 tty = tty_port_tty_get(&dlci->port);
1118 gsm_process_modem(tty, dlci, modem, clen);
1119 if (tty) {
1120 tty_wakeup(tty);
1121 tty_kref_put(tty);
1122 }
1123 gsm_control_reply(gsm, CMD_MSC, data, clen);
1124}
1125
1126/**
1127 * gsm_control_rls - remote line status
1128 * @gsm: GSM channel
1129 * @data: data bytes
1130 * @clen: data length
1131 *
1132 * The modem sends us a two byte message on the control channel whenever
1133 * it wishes to send us an error state from the virtual link. Stuff
1134 * this into the uplink tty if present
1135 */
1136
1137static void gsm_control_rls(struct gsm_mux *gsm, const u8 *data, int clen)
1138{
1139 struct tty_port *port;
1140 unsigned int addr = 0;
1141 u8 bits;
1142 int len = clen;
1143 const u8 *dp = data;
1144
1145 while (gsm_read_ea(&addr, *dp++) == 0) {
1146 len--;
1147 if (len == 0)
1148 return;
1149 }
1150 /* Must be at least one byte following ea */
1151 len--;
1152 if (len <= 0)
1153 return;
1154 addr >>= 1;
1155 /* Closed port, or invalid ? */
1156 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1157 return;
1158 /* No error ? */
1159 bits = *dp;
1160 if ((bits & 1) == 0)
1161 return;
1162
1163 port = &gsm->dlci[addr]->port;
1164
1165 if (bits & 2)
1166 tty_insert_flip_char(port, 0, TTY_OVERRUN);
1167 if (bits & 4)
1168 tty_insert_flip_char(port, 0, TTY_PARITY);
1169 if (bits & 8)
1170 tty_insert_flip_char(port, 0, TTY_FRAME);
1171
1172 tty_flip_buffer_push(port);
1173
1174 gsm_control_reply(gsm, CMD_RLS, data, clen);
1175}
1176
1177static void gsm_dlci_begin_close(struct gsm_dlci *dlci);
1178
1179/**
1180 * gsm_control_message - DLCI 0 control processing
1181 * @gsm: our GSM mux
1182 * @command: the command EA
1183 * @data: data beyond the command/length EAs
1184 * @clen: length
1185 *
1186 * Input processor for control messages from the other end of the link.
1187 * Processes the incoming request and queues a response frame or an
1188 * NSC response if not supported
1189 */
1190
1191static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
1192 const u8 *data, int clen)
1193{
1194 u8 buf[1];
1195 unsigned long flags;
1196
1197 switch (command) {
1198 case CMD_CLD: {
1199 struct gsm_dlci *dlci = gsm->dlci[0];
1200 /* Modem wishes to close down */
1201 if (dlci) {
1202 dlci->dead = 1;
1203 gsm->dead = 1;
1204 gsm_dlci_begin_close(dlci);
1205 }
1206 }
1207 break;
1208 case CMD_TEST:
1209 /* Modem wishes to test, reply with the data */
1210 gsm_control_reply(gsm, CMD_TEST, data, clen);
1211 break;
1212 case CMD_FCON:
1213 /* Modem can accept data again */
1214 gsm->constipated = 0;
1215 gsm_control_reply(gsm, CMD_FCON, NULL, 0);
1216 /* Kick the link in case it is idling */
1217 spin_lock_irqsave(&gsm->tx_lock, flags);
1218 gsm_data_kick(gsm);
1219 spin_unlock_irqrestore(&gsm->tx_lock, flags);
1220 break;
1221 case CMD_FCOFF:
1222 /* Modem wants us to STFU */
1223 gsm->constipated = 1;
1224 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0);
1225 break;
1226 case CMD_MSC:
1227 /* Out of band modem line change indicator for a DLCI */
1228 gsm_control_modem(gsm, data, clen);
1229 break;
1230 case CMD_RLS:
1231 /* Out of band error reception for a DLCI */
1232 gsm_control_rls(gsm, data, clen);
1233 break;
1234 case CMD_PSC:
1235 /* Modem wishes to enter power saving state */
1236 gsm_control_reply(gsm, CMD_PSC, NULL, 0);
1237 break;
1238 /* Optional unsupported commands */
1239 case CMD_PN: /* Parameter negotiation */
1240 case CMD_RPN: /* Remote port negotiation */
1241 case CMD_SNC: /* Service negotiation command */
1242 default:
1243 /* Reply to bad commands with an NSC */
1244 buf[0] = command;
1245 gsm_control_reply(gsm, CMD_NSC, buf, 1);
1246 break;
1247 }
1248}
1249
1250/**
1251 * gsm_control_response - process a response to our control
1252 * @gsm: our GSM mux
1253 * @command: the command (response) EA
1254 * @data: data beyond the command/length EA
1255 * @clen: length
1256 *
1257 * Process a response to an outstanding command. We only allow a single
1258 * control message in flight so this is fairly easy. All the clean up
1259 * is done by the caller, we just update the fields, flag it as done
1260 * and return
1261 */
1262
1263static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
1264 const u8 *data, int clen)
1265{
1266 struct gsm_control *ctrl;
1267 unsigned long flags;
1268
1269 spin_lock_irqsave(&gsm->control_lock, flags);
1270
1271 ctrl = gsm->pending_cmd;
1272 /* Does the reply match our command */
1273 command |= 1;
1274 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) {
1275 /* Our command was replied to, kill the retry timer */
1276 del_timer(&gsm->t2_timer);
1277 gsm->pending_cmd = NULL;
1278 /* Rejected by the other end */
1279 if (command == CMD_NSC)
1280 ctrl->error = -EOPNOTSUPP;
1281 ctrl->done = 1;
1282 wake_up(&gsm->event);
1283 }
1284 spin_unlock_irqrestore(&gsm->control_lock, flags);
1285}
1286
1287/**
1288 * gsm_control_transmit - send control packet
1289 * @gsm: gsm mux
1290 * @ctrl: frame to send
1291 *
1292 * Send out a pending control command (called under control lock)
1293 */
1294
1295static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl)
1296{
1297 struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, gsm->ftype);
1298 if (msg == NULL)
1299 return;
1300 msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */
1301 memcpy(msg->data + 1, ctrl->data, ctrl->len);
1302 gsm_data_queue(gsm->dlci[0], msg);
1303}
1304
1305/**
1306 * gsm_control_retransmit - retransmit a control frame
1307 * @data: pointer to our gsm object
1308 *
1309 * Called off the T2 timer expiry in order to retransmit control frames
1310 * that have been lost in the system somewhere. The control_lock protects
1311 * us from colliding with another sender or a receive completion event.
1312 * In that situation the timer may still occur in a small window but
1313 * gsm->pending_cmd will be NULL and we just let the timer expire.
1314 */
1315
1316static void gsm_control_retransmit(struct timer_list *t)
1317{
1318 struct gsm_mux *gsm = from_timer(gsm, t, t2_timer);
1319 struct gsm_control *ctrl;
1320 unsigned long flags;
1321 spin_lock_irqsave(&gsm->control_lock, flags);
1322 ctrl = gsm->pending_cmd;
1323 if (ctrl) {
1324 gsm->cretries--;
1325 if (gsm->cretries == 0) {
1326 gsm->pending_cmd = NULL;
1327 ctrl->error = -ETIMEDOUT;
1328 ctrl->done = 1;
1329 spin_unlock_irqrestore(&gsm->control_lock, flags);
1330 wake_up(&gsm->event);
1331 return;
1332 }
1333 gsm_control_transmit(gsm, ctrl);
1334 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1335 }
1336 spin_unlock_irqrestore(&gsm->control_lock, flags);
1337}
1338
1339/**
1340 * gsm_control_send - send a control frame on DLCI 0
1341 * @gsm: the GSM channel
1342 * @command: command to send including CR bit
1343 * @data: bytes of data (must be kmalloced)
1344 * @len: length of the block to send
1345 *
1346 * Queue and dispatch a control command. Only one command can be
1347 * active at a time. In theory more can be outstanding but the matching
1348 * gets really complicated so for now stick to one outstanding.
1349 */
1350
1351static struct gsm_control *gsm_control_send(struct gsm_mux *gsm,
1352 unsigned int command, u8 *data, int clen)
1353{
1354 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control),
1355 GFP_KERNEL);
1356 unsigned long flags;
1357 if (ctrl == NULL)
1358 return NULL;
1359retry:
1360 wait_event(gsm->event, gsm->pending_cmd == NULL);
1361 spin_lock_irqsave(&gsm->control_lock, flags);
1362 if (gsm->pending_cmd != NULL) {
1363 spin_unlock_irqrestore(&gsm->control_lock, flags);
1364 goto retry;
1365 }
1366 ctrl->cmd = command;
1367 ctrl->data = data;
1368 ctrl->len = clen;
1369 gsm->pending_cmd = ctrl;
1370
1371 /* If DLCI0 is in ADM mode skip retries, it won't respond */
1372 if (gsm->dlci[0]->mode == DLCI_MODE_ADM)
1373 gsm->cretries = 1;
1374 else
1375 gsm->cretries = gsm->n2;
1376
1377 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1378 gsm_control_transmit(gsm, ctrl);
1379 spin_unlock_irqrestore(&gsm->control_lock, flags);
1380 return ctrl;
1381}
1382
1383/**
1384 * gsm_control_wait - wait for a control to finish
1385 * @gsm: GSM mux
1386 * @control: control we are waiting on
1387 *
1388 * Waits for the control to complete or time out. Frees any used
1389 * resources and returns 0 for success, or an error if the remote
1390 * rejected or ignored the request.
1391 */
1392
1393static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
1394{
1395 int err;
1396 wait_event(gsm->event, control->done == 1);
1397 err = control->error;
1398 kfree(control);
1399 return err;
1400}
1401
1402
1403/*
1404 * DLCI level handling: Needs krefs
1405 */
1406
1407/*
1408 * State transitions and timers
1409 */
1410
1411/**
1412 * gsm_dlci_close - a DLCI has closed
1413 * @dlci: DLCI that closed
1414 *
1415 * Perform processing when moving a DLCI into closed state. If there
1416 * is an attached tty this is hung up
1417 */
1418
1419static void gsm_dlci_close(struct gsm_dlci *dlci)
1420{
1421 del_timer(&dlci->t1);
1422 if (debug & 8)
1423 pr_debug("DLCI %d goes closed.\n", dlci->addr);
1424 dlci->state = DLCI_CLOSED;
1425 if (dlci->addr != 0) {
1426 tty_port_tty_hangup(&dlci->port, false);
1427 kfifo_reset(dlci->fifo);
1428 } else
1429 dlci->gsm->dead = 1;
1430 wake_up(&dlci->gsm->event);
1431 /* A DLCI 0 close is a MUX termination so we need to kick that
1432 back to userspace somehow */
1433}
1434
1435/**
1436 * gsm_dlci_open - a DLCI has opened
1437 * @dlci: DLCI that opened
1438 *
1439 * Perform processing when moving a DLCI into open state.
1440 */
1441
1442static void gsm_dlci_open(struct gsm_dlci *dlci)
1443{
1444 /* Note that SABM UA .. SABM UA first UA lost can mean that we go
1445 open -> open */
1446 del_timer(&dlci->t1);
1447 /* This will let a tty open continue */
1448 dlci->state = DLCI_OPEN;
1449 if (debug & 8)
1450 pr_debug("DLCI %d goes open.\n", dlci->addr);
1451 wake_up(&dlci->gsm->event);
1452}
1453
1454/**
1455 * gsm_dlci_t1 - T1 timer expiry
1456 * @dlci: DLCI that opened
1457 *
1458 * The T1 timer handles retransmits of control frames (essentially of
1459 * SABM and DISC). We resend the command until the retry count runs out
1460 * in which case an opening port goes back to closed and a closing port
1461 * is simply put into closed state (any further frames from the other
1462 * end will get a DM response)
1463 *
1464 * Some control dlci can stay in ADM mode with other dlci working just
1465 * fine. In that case we can just keep the control dlci open after the
1466 * DLCI_OPENING retries time out.
1467 */
1468
1469static void gsm_dlci_t1(struct timer_list *t)
1470{
1471 struct gsm_dlci *dlci = from_timer(dlci, t, t1);
1472 struct gsm_mux *gsm = dlci->gsm;
1473
1474 switch (dlci->state) {
1475 case DLCI_OPENING:
1476 dlci->retries--;
1477 if (dlci->retries) {
1478 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1479 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1480 } else if (!dlci->addr && gsm->control == (DM | PF)) {
1481 if (debug & 8)
1482 pr_info("DLCI %d opening in ADM mode.\n",
1483 dlci->addr);
1484 dlci->mode = DLCI_MODE_ADM;
1485 gsm_dlci_open(dlci);
1486 } else {
1487 gsm_dlci_close(dlci);
1488 }
1489
1490 break;
1491 case DLCI_CLOSING:
1492 dlci->retries--;
1493 if (dlci->retries) {
1494 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1495 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1496 } else
1497 gsm_dlci_close(dlci);
1498 break;
1499 }
1500}
1501
1502/**
1503 * gsm_dlci_begin_open - start channel open procedure
1504 * @dlci: DLCI to open
1505 *
1506 * Commence opening a DLCI from the Linux side. We issue SABM messages
1507 * to the modem which should then reply with a UA or ADM, at which point
1508 * we will move into open state. Opening is done asynchronously with retry
1509 * running off timers and the responses.
1510 */
1511
1512static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
1513{
1514 struct gsm_mux *gsm = dlci->gsm;
1515 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING)
1516 return;
1517 dlci->retries = gsm->n2;
1518 dlci->state = DLCI_OPENING;
1519 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1520 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1521}
1522
1523/**
1524 * gsm_dlci_begin_close - start channel open procedure
1525 * @dlci: DLCI to open
1526 *
1527 * Commence closing a DLCI from the Linux side. We issue DISC messages
1528 * to the modem which should then reply with a UA, at which point we
1529 * will move into closed state. Closing is done asynchronously with retry
1530 * off timers. We may also receive a DM reply from the other end which
1531 * indicates the channel was already closed.
1532 */
1533
1534static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
1535{
1536 struct gsm_mux *gsm = dlci->gsm;
1537 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
1538 return;
1539 dlci->retries = gsm->n2;
1540 dlci->state = DLCI_CLOSING;
1541 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1542 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1543}
1544
1545/**
1546 * gsm_dlci_data - data arrived
1547 * @dlci: channel
1548 * @data: block of bytes received
1549 * @len: length of received block
1550 *
1551 * A UI or UIH frame has arrived which contains data for a channel
1552 * other than the control channel. If the relevant virtual tty is
1553 * open we shovel the bits down it, if not we drop them.
1554 */
1555
1556static void gsm_dlci_data(struct gsm_dlci *dlci, const u8 *data, int clen)
1557{
1558 /* krefs .. */
1559 struct tty_port *port = &dlci->port;
1560 struct tty_struct *tty;
1561 unsigned int modem = 0;
1562 int len = clen;
1563
1564 if (debug & 16)
1565 pr_debug("%d bytes for tty\n", len);
1566 switch (dlci->adaption) {
1567 /* Unsupported types */
1568 case 4: /* Packetised interruptible data */
1569 break;
1570 case 3: /* Packetised uininterruptible voice/data */
1571 break;
1572 case 2: /* Asynchronous serial with line state in each frame */
1573 while (gsm_read_ea(&modem, *data++) == 0) {
1574 len--;
1575 if (len == 0)
1576 return;
1577 }
1578 tty = tty_port_tty_get(port);
1579 if (tty) {
1580 gsm_process_modem(tty, dlci, modem, clen);
1581 tty_kref_put(tty);
1582 }
1583 /* Fall through */
1584 case 1: /* Line state will go via DLCI 0 controls only */
1585 default:
1586 tty_insert_flip_string(port, data, len);
1587 tty_flip_buffer_push(port);
1588 }
1589}
1590
1591/**
1592 * gsm_dlci_control - data arrived on control channel
1593 * @dlci: channel
1594 * @data: block of bytes received
1595 * @len: length of received block
1596 *
1597 * A UI or UIH frame has arrived which contains data for DLCI 0 the
1598 * control channel. This should contain a command EA followed by
1599 * control data bytes. The command EA contains a command/response bit
1600 * and we divide up the work accordingly.
1601 */
1602
1603static void gsm_dlci_command(struct gsm_dlci *dlci, const u8 *data, int len)
1604{
1605 /* See what command is involved */
1606 unsigned int command = 0;
1607 while (len-- > 0) {
1608 if (gsm_read_ea(&command, *data++) == 1) {
1609 int clen = *data++;
1610 len--;
1611 /* FIXME: this is properly an EA */
1612 clen >>= 1;
1613 /* Malformed command ? */
1614 if (clen > len)
1615 return;
1616 if (command & 1)
1617 gsm_control_message(dlci->gsm, command,
1618 data, clen);
1619 else
1620 gsm_control_response(dlci->gsm, command,
1621 data, clen);
1622 return;
1623 }
1624 }
1625}
1626
1627/*
1628 * Allocate/Free DLCI channels
1629 */
1630
1631/**
1632 * gsm_dlci_alloc - allocate a DLCI
1633 * @gsm: GSM mux
1634 * @addr: address of the DLCI
1635 *
1636 * Allocate and install a new DLCI object into the GSM mux.
1637 *
1638 * FIXME: review locking races
1639 */
1640
1641static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
1642{
1643 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC);
1644 if (dlci == NULL)
1645 return NULL;
1646 spin_lock_init(&dlci->lock);
1647 mutex_init(&dlci->mutex);
1648 dlci->fifo = &dlci->_fifo;
1649 if (kfifo_alloc(&dlci->_fifo, 4096, GFP_KERNEL) < 0) {
1650 kfree(dlci);
1651 return NULL;
1652 }
1653
1654 skb_queue_head_init(&dlci->skb_list);
1655 timer_setup(&dlci->t1, gsm_dlci_t1, 0);
1656 tty_port_init(&dlci->port);
1657 dlci->port.ops = &gsm_port_ops;
1658 dlci->gsm = gsm;
1659 dlci->addr = addr;
1660 dlci->adaption = gsm->adaption;
1661 dlci->state = DLCI_CLOSED;
1662 if (addr)
1663 dlci->data = gsm_dlci_data;
1664 else
1665 dlci->data = gsm_dlci_command;
1666 gsm->dlci[addr] = dlci;
1667 return dlci;
1668}
1669
1670/**
1671 * gsm_dlci_free - free DLCI
1672 * @dlci: DLCI to free
1673 *
1674 * Free up a DLCI.
1675 *
1676 * Can sleep.
1677 */
1678static void gsm_dlci_free(struct tty_port *port)
1679{
1680 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
1681
1682 del_timer_sync(&dlci->t1);
1683 dlci->gsm->dlci[dlci->addr] = NULL;
1684 kfifo_free(dlci->fifo);
1685 while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
1686 dev_kfree_skb(dlci->skb);
1687 kfree(dlci);
1688}
1689
1690static inline void dlci_get(struct gsm_dlci *dlci)
1691{
1692 tty_port_get(&dlci->port);
1693}
1694
1695static inline void dlci_put(struct gsm_dlci *dlci)
1696{
1697 tty_port_put(&dlci->port);
1698}
1699
1700static void gsm_destroy_network(struct gsm_dlci *dlci);
1701
1702/**
1703 * gsm_dlci_release - release DLCI
1704 * @dlci: DLCI to destroy
1705 *
1706 * Release a DLCI. Actual free is deferred until either
1707 * mux is closed or tty is closed - whichever is last.
1708 *
1709 * Can sleep.
1710 */
1711static void gsm_dlci_release(struct gsm_dlci *dlci)
1712{
1713 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1714 if (tty) {
1715 mutex_lock(&dlci->mutex);
1716 gsm_destroy_network(dlci);
1717 mutex_unlock(&dlci->mutex);
1718
1719 tty_hangup(tty);
1720
1721 tty_port_tty_set(&dlci->port, NULL);
1722 tty_kref_put(tty);
1723 }
1724 dlci->state = DLCI_CLOSED;
1725 dlci_put(dlci);
1726}
1727
1728/*
1729 * LAPBish link layer logic
1730 */
1731
1732/**
1733 * gsm_queue - a GSM frame is ready to process
1734 * @gsm: pointer to our gsm mux
1735 *
1736 * At this point in time a frame has arrived and been demangled from
1737 * the line encoding. All the differences between the encodings have
1738 * been handled below us and the frame is unpacked into the structures.
1739 * The fcs holds the header FCS but any data FCS must be added here.
1740 */
1741
1742static void gsm_queue(struct gsm_mux *gsm)
1743{
1744 struct gsm_dlci *dlci;
1745 u8 cr;
1746 int address;
1747 /* We have to sneak a look at the packet body to do the FCS.
1748 A somewhat layering violation in the spec */
1749
1750 if ((gsm->control & ~PF) == UI)
1751 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len);
1752 if (gsm->encoding == 0) {
1753 /* WARNING: gsm->received_fcs is used for
1754 gsm->encoding = 0 only.
1755 In this case it contain the last piece of data
1756 required to generate final CRC */
1757 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs);
1758 }
1759 if (gsm->fcs != GOOD_FCS) {
1760 gsm->bad_fcs++;
1761 if (debug & 4)
1762 pr_debug("BAD FCS %02x\n", gsm->fcs);
1763 return;
1764 }
1765 address = gsm->address >> 1;
1766 if (address >= NUM_DLCI)
1767 goto invalid;
1768
1769 cr = gsm->address & 1; /* C/R bit */
1770
1771 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
1772
1773 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */
1774 dlci = gsm->dlci[address];
1775
1776 switch (gsm->control) {
1777 case SABM|PF:
1778 if (cr == 0)
1779 goto invalid;
1780 if (dlci == NULL)
1781 dlci = gsm_dlci_alloc(gsm, address);
1782 if (dlci == NULL)
1783 return;
1784 if (dlci->dead)
1785 gsm_response(gsm, address, DM);
1786 else {
1787 gsm_response(gsm, address, UA);
1788 gsm_dlci_open(dlci);
1789 }
1790 break;
1791 case DISC|PF:
1792 if (cr == 0)
1793 goto invalid;
1794 if (dlci == NULL || dlci->state == DLCI_CLOSED) {
1795 gsm_response(gsm, address, DM);
1796 return;
1797 }
1798 /* Real close complete */
1799 gsm_response(gsm, address, UA);
1800 gsm_dlci_close(dlci);
1801 break;
1802 case UA:
1803 case UA|PF:
1804 if (cr == 0 || dlci == NULL)
1805 break;
1806 switch (dlci->state) {
1807 case DLCI_CLOSING:
1808 gsm_dlci_close(dlci);
1809 break;
1810 case DLCI_OPENING:
1811 gsm_dlci_open(dlci);
1812 break;
1813 }
1814 break;
1815 case DM: /* DM can be valid unsolicited */
1816 case DM|PF:
1817 if (cr)
1818 goto invalid;
1819 if (dlci == NULL)
1820 return;
1821 gsm_dlci_close(dlci);
1822 break;
1823 case UI:
1824 case UI|PF:
1825 case UIH:
1826 case UIH|PF:
1827#if 0
1828 if (cr)
1829 goto invalid;
1830#endif
1831 if (dlci == NULL || dlci->state != DLCI_OPEN) {
1832 gsm_command(gsm, address, DM|PF);
1833 return;
1834 }
1835 dlci->data(dlci, gsm->buf, gsm->len);
1836 break;
1837 default:
1838 goto invalid;
1839 }
1840 return;
1841invalid:
1842 gsm->malformed++;
1843 return;
1844}
1845
1846
1847/**
1848 * gsm0_receive - perform processing for non-transparency
1849 * @gsm: gsm data for this ldisc instance
1850 * @c: character
1851 *
1852 * Receive bytes in gsm mode 0
1853 */
1854
1855static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
1856{
1857 unsigned int len;
1858
1859 switch (gsm->state) {
1860 case GSM_SEARCH: /* SOF marker */
1861 if (c == GSM0_SOF) {
1862 gsm->state = GSM_ADDRESS;
1863 gsm->address = 0;
1864 gsm->len = 0;
1865 gsm->fcs = INIT_FCS;
1866 }
1867 break;
1868 case GSM_ADDRESS: /* Address EA */
1869 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1870 if (gsm_read_ea(&gsm->address, c))
1871 gsm->state = GSM_CONTROL;
1872 break;
1873 case GSM_CONTROL: /* Control Byte */
1874 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1875 gsm->control = c;
1876 gsm->state = GSM_LEN0;
1877 break;
1878 case GSM_LEN0: /* Length EA */
1879 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1880 if (gsm_read_ea(&gsm->len, c)) {
1881 if (gsm->len > gsm->mru) {
1882 gsm->bad_size++;
1883 gsm->state = GSM_SEARCH;
1884 break;
1885 }
1886 gsm->count = 0;
1887 if (!gsm->len)
1888 gsm->state = GSM_FCS;
1889 else
1890 gsm->state = GSM_DATA;
1891 break;
1892 }
1893 gsm->state = GSM_LEN1;
1894 break;
1895 case GSM_LEN1:
1896 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1897 len = c;
1898 gsm->len |= len << 7;
1899 if (gsm->len > gsm->mru) {
1900 gsm->bad_size++;
1901 gsm->state = GSM_SEARCH;
1902 break;
1903 }
1904 gsm->count = 0;
1905 if (!gsm->len)
1906 gsm->state = GSM_FCS;
1907 else
1908 gsm->state = GSM_DATA;
1909 break;
1910 case GSM_DATA: /* Data */
1911 gsm->buf[gsm->count++] = c;
1912 if (gsm->count == gsm->len)
1913 gsm->state = GSM_FCS;
1914 break;
1915 case GSM_FCS: /* FCS follows the packet */
1916 gsm->received_fcs = c;
1917 gsm_queue(gsm);
1918 gsm->state = GSM_SSOF;
1919 break;
1920 case GSM_SSOF:
1921 if (c == GSM0_SOF) {
1922 gsm->state = GSM_SEARCH;
1923 break;
1924 }
1925 break;
1926 }
1927}
1928
1929/**
1930 * gsm1_receive - perform processing for non-transparency
1931 * @gsm: gsm data for this ldisc instance
1932 * @c: character
1933 *
1934 * Receive bytes in mode 1 (Advanced option)
1935 */
1936
1937static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
1938{
1939 if (c == GSM1_SOF) {
1940 /* EOF is only valid in frame if we have got to the data state
1941 and received at least one byte (the FCS) */
1942 if (gsm->state == GSM_DATA && gsm->count) {
1943 /* Extract the FCS */
1944 gsm->count--;
1945 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
1946 gsm->len = gsm->count;
1947 gsm_queue(gsm);
1948 gsm->state = GSM_START;
1949 return;
1950 }
1951 /* Any partial frame was a runt so go back to start */
1952 if (gsm->state != GSM_START) {
1953 gsm->malformed++;
1954 gsm->state = GSM_START;
1955 }
1956 /* A SOF in GSM_START means we are still reading idling or
1957 framing bytes */
1958 return;
1959 }
1960
1961 if (c == GSM1_ESCAPE) {
1962 gsm->escape = 1;
1963 return;
1964 }
1965
1966 /* Only an unescaped SOF gets us out of GSM search */
1967 if (gsm->state == GSM_SEARCH)
1968 return;
1969
1970 if (gsm->escape) {
1971 c ^= GSM1_ESCAPE_BITS;
1972 gsm->escape = 0;
1973 }
1974 switch (gsm->state) {
1975 case GSM_START: /* First byte after SOF */
1976 gsm->address = 0;
1977 gsm->state = GSM_ADDRESS;
1978 gsm->fcs = INIT_FCS;
1979 /* Fall through */
1980 case GSM_ADDRESS: /* Address continuation */
1981 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1982 if (gsm_read_ea(&gsm->address, c))
1983 gsm->state = GSM_CONTROL;
1984 break;
1985 case GSM_CONTROL: /* Control Byte */
1986 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1987 gsm->control = c;
1988 gsm->count = 0;
1989 gsm->state = GSM_DATA;
1990 break;
1991 case GSM_DATA: /* Data */
1992 if (gsm->count > gsm->mru) { /* Allow one for the FCS */
1993 gsm->state = GSM_OVERRUN;
1994 gsm->bad_size++;
1995 } else
1996 gsm->buf[gsm->count++] = c;
1997 break;
1998 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */
1999 break;
2000 }
2001}
2002
2003/**
2004 * gsm_error - handle tty error
2005 * @gsm: ldisc data
2006 * @data: byte received (may be invalid)
2007 * @flag: error received
2008 *
2009 * Handle an error in the receipt of data for a frame. Currently we just
2010 * go back to hunting for a SOF.
2011 *
2012 * FIXME: better diagnostics ?
2013 */
2014
2015static void gsm_error(struct gsm_mux *gsm,
2016 unsigned char data, unsigned char flag)
2017{
2018 gsm->state = GSM_SEARCH;
2019 gsm->io_error++;
2020}
2021
2022static int gsm_disconnect(struct gsm_mux *gsm)
2023{
2024 struct gsm_dlci *dlci = gsm->dlci[0];
2025 struct gsm_control *gc;
2026
2027 if (!dlci)
2028 return 0;
2029
2030 /* In theory disconnecting DLCI 0 is sufficient but for some
2031 modems this is apparently not the case. */
2032 gc = gsm_control_send(gsm, CMD_CLD, NULL, 0);
2033 if (gc)
2034 gsm_control_wait(gsm, gc);
2035
2036 del_timer_sync(&gsm->t2_timer);
2037 /* Now we are sure T2 has stopped */
2038
2039 gsm_dlci_begin_close(dlci);
2040 wait_event_interruptible(gsm->event,
2041 dlci->state == DLCI_CLOSED);
2042
2043 if (signal_pending(current))
2044 return -EINTR;
2045
2046 return 0;
2047}
2048
2049/**
2050 * gsm_cleanup_mux - generic GSM protocol cleanup
2051 * @gsm: our mux
2052 *
2053 * Clean up the bits of the mux which are the same for all framing
2054 * protocols. Remove the mux from the mux table, stop all the timers
2055 * and then shut down each device hanging up the channels as we go.
2056 */
2057
2058static void gsm_cleanup_mux(struct gsm_mux *gsm)
2059{
2060 int i;
2061 struct gsm_dlci *dlci = gsm->dlci[0];
2062 struct gsm_msg *txq, *ntxq;
2063
2064 gsm->dead = 1;
2065
2066 spin_lock(&gsm_mux_lock);
2067 for (i = 0; i < MAX_MUX; i++) {
2068 if (gsm_mux[i] == gsm) {
2069 gsm_mux[i] = NULL;
2070 break;
2071 }
2072 }
2073 spin_unlock(&gsm_mux_lock);
2074 /* open failed before registering => nothing to do */
2075 if (i == MAX_MUX)
2076 return;
2077
2078 del_timer_sync(&gsm->t2_timer);
2079 /* Now we are sure T2 has stopped */
2080 if (dlci)
2081 dlci->dead = 1;
2082
2083 /* Free up any link layer users */
2084 mutex_lock(&gsm->mutex);
2085 for (i = 0; i < NUM_DLCI; i++)
2086 if (gsm->dlci[i])
2087 gsm_dlci_release(gsm->dlci[i]);
2088 mutex_unlock(&gsm->mutex);
2089 /* Now wipe the queues */
2090 list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list)
2091 kfree(txq);
2092 INIT_LIST_HEAD(&gsm->tx_list);
2093}
2094
2095/**
2096 * gsm_activate_mux - generic GSM setup
2097 * @gsm: our mux
2098 *
2099 * Set up the bits of the mux which are the same for all framing
2100 * protocols. Add the mux to the mux table so it can be opened and
2101 * finally kick off connecting to DLCI 0 on the modem.
2102 */
2103
2104static int gsm_activate_mux(struct gsm_mux *gsm)
2105{
2106 struct gsm_dlci *dlci;
2107 int i = 0;
2108
2109 timer_setup(&gsm->t2_timer, gsm_control_retransmit, 0);
2110 init_waitqueue_head(&gsm->event);
2111 spin_lock_init(&gsm->control_lock);
2112 spin_lock_init(&gsm->tx_lock);
2113
2114 if (gsm->encoding == 0)
2115 gsm->receive = gsm0_receive;
2116 else
2117 gsm->receive = gsm1_receive;
2118 gsm->error = gsm_error;
2119
2120 spin_lock(&gsm_mux_lock);
2121 for (i = 0; i < MAX_MUX; i++) {
2122 if (gsm_mux[i] == NULL) {
2123 gsm->num = i;
2124 gsm_mux[i] = gsm;
2125 break;
2126 }
2127 }
2128 spin_unlock(&gsm_mux_lock);
2129 if (i == MAX_MUX)
2130 return -EBUSY;
2131
2132 dlci = gsm_dlci_alloc(gsm, 0);
2133 if (dlci == NULL)
2134 return -ENOMEM;
2135 gsm->dead = 0; /* Tty opens are now permissible */
2136 return 0;
2137}
2138
2139/**
2140 * gsm_free_mux - free up a mux
2141 * @mux: mux to free
2142 *
2143 * Dispose of allocated resources for a dead mux
2144 */
2145static void gsm_free_mux(struct gsm_mux *gsm)
2146{
2147 kfree(gsm->txframe);
2148 kfree(gsm->buf);
2149 kfree(gsm);
2150}
2151
2152/**
2153 * gsm_free_muxr - free up a mux
2154 * @mux: mux to free
2155 *
2156 * Dispose of allocated resources for a dead mux
2157 */
2158static void gsm_free_muxr(struct kref *ref)
2159{
2160 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref);
2161 gsm_free_mux(gsm);
2162}
2163
2164static inline void mux_get(struct gsm_mux *gsm)
2165{
2166 kref_get(&gsm->ref);
2167}
2168
2169static inline void mux_put(struct gsm_mux *gsm)
2170{
2171 kref_put(&gsm->ref, gsm_free_muxr);
2172}
2173
2174static inline unsigned int mux_num_to_base(struct gsm_mux *gsm)
2175{
2176 return gsm->num * NUM_DLCI;
2177}
2178
2179static inline unsigned int mux_line_to_num(unsigned int line)
2180{
2181 return line / NUM_DLCI;
2182}
2183
2184/**
2185 * gsm_alloc_mux - allocate a mux
2186 *
2187 * Creates a new mux ready for activation.
2188 */
2189
2190static struct gsm_mux *gsm_alloc_mux(void)
2191{
2192 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
2193 if (gsm == NULL)
2194 return NULL;
2195 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL);
2196 if (gsm->buf == NULL) {
2197 kfree(gsm);
2198 return NULL;
2199 }
2200 gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL);
2201 if (gsm->txframe == NULL) {
2202 kfree(gsm->buf);
2203 kfree(gsm);
2204 return NULL;
2205 }
2206 spin_lock_init(&gsm->lock);
2207 mutex_init(&gsm->mutex);
2208 kref_init(&gsm->ref);
2209 INIT_LIST_HEAD(&gsm->tx_list);
2210
2211 gsm->t1 = T1;
2212 gsm->t2 = T2;
2213 gsm->n2 = N2;
2214 gsm->ftype = UIH;
2215 gsm->adaption = 1;
2216 gsm->encoding = 1;
2217 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
2218 gsm->mtu = 64;
2219 gsm->dead = 1; /* Avoid early tty opens */
2220
2221 return gsm;
2222}
2223
2224static void gsm_copy_config_values(struct gsm_mux *gsm,
2225 struct gsm_config *c)
2226{
2227 memset(c, 0, sizeof(*c));
2228 c->adaption = gsm->adaption;
2229 c->encapsulation = gsm->encoding;
2230 c->initiator = gsm->initiator;
2231 c->t1 = gsm->t1;
2232 c->t2 = gsm->t2;
2233 c->t3 = 0; /* Not supported */
2234 c->n2 = gsm->n2;
2235 if (gsm->ftype == UIH)
2236 c->i = 1;
2237 else
2238 c->i = 2;
2239 pr_debug("Ftype %d i %d\n", gsm->ftype, c->i);
2240 c->mru = gsm->mru;
2241 c->mtu = gsm->mtu;
2242 c->k = 0;
2243}
2244
2245static int gsm_config(struct gsm_mux *gsm, struct gsm_config *c)
2246{
2247 int need_close = 0;
2248 int need_restart = 0;
2249
2250 /* Stuff we don't support yet - UI or I frame transport, windowing */
2251 if ((c->adaption != 1 && c->adaption != 2) || c->k)
2252 return -EOPNOTSUPP;
2253 /* Check the MRU/MTU range looks sane */
2254 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8)
2255 return -EINVAL;
2256 if (c->n2 < 3)
2257 return -EINVAL;
2258 if (c->encapsulation > 1) /* Basic, advanced, no I */
2259 return -EINVAL;
2260 if (c->initiator > 1)
2261 return -EINVAL;
2262 if (c->i == 0 || c->i > 2) /* UIH and UI only */
2263 return -EINVAL;
2264 /*
2265 * See what is needed for reconfiguration
2266 */
2267
2268 /* Timing fields */
2269 if (c->t1 != 0 && c->t1 != gsm->t1)
2270 need_restart = 1;
2271 if (c->t2 != 0 && c->t2 != gsm->t2)
2272 need_restart = 1;
2273 if (c->encapsulation != gsm->encoding)
2274 need_restart = 1;
2275 if (c->adaption != gsm->adaption)
2276 need_restart = 1;
2277 /* Requires care */
2278 if (c->initiator != gsm->initiator)
2279 need_close = 1;
2280 if (c->mru != gsm->mru)
2281 need_restart = 1;
2282 if (c->mtu != gsm->mtu)
2283 need_restart = 1;
2284
2285 /*
2286 * Close down what is needed, restart and initiate the new
2287 * configuration
2288 */
2289
2290 if (need_close || need_restart) {
2291 int ret;
2292
2293 ret = gsm_disconnect(gsm);
2294
2295 if (ret)
2296 return ret;
2297 }
2298 if (need_restart)
2299 gsm_cleanup_mux(gsm);
2300
2301 gsm->initiator = c->initiator;
2302 gsm->mru = c->mru;
2303 gsm->mtu = c->mtu;
2304 gsm->encoding = c->encapsulation;
2305 gsm->adaption = c->adaption;
2306 gsm->n2 = c->n2;
2307
2308 if (c->i == 1)
2309 gsm->ftype = UIH;
2310 else if (c->i == 2)
2311 gsm->ftype = UI;
2312
2313 if (c->t1)
2314 gsm->t1 = c->t1;
2315 if (c->t2)
2316 gsm->t2 = c->t2;
2317
2318 /*
2319 * FIXME: We need to separate activation/deactivation from adding
2320 * and removing from the mux array
2321 */
2322 if (need_restart)
2323 gsm_activate_mux(gsm);
2324 if (gsm->initiator && need_close)
2325 gsm_dlci_begin_open(gsm->dlci[0]);
2326 return 0;
2327}
2328
2329/**
2330 * gsmld_output - write to link
2331 * @gsm: our mux
2332 * @data: bytes to output
2333 * @len: size
2334 *
2335 * Write a block of data from the GSM mux to the data channel. This
2336 * will eventually be serialized from above but at the moment isn't.
2337 */
2338
2339static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
2340{
2341 if (tty_write_room(gsm->tty) < len) {
2342 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
2343 return -ENOSPC;
2344 }
2345 if (debug & 4)
2346 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET,
2347 data, len);
2348 gsm->tty->ops->write(gsm->tty, data, len);
2349 return len;
2350}
2351
2352/**
2353 * gsmld_attach_gsm - mode set up
2354 * @tty: our tty structure
2355 * @gsm: our mux
2356 *
2357 * Set up the MUX for basic mode and commence connecting to the
2358 * modem. Currently called from the line discipline set up but
2359 * will need moving to an ioctl path.
2360 */
2361
2362static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2363{
2364 unsigned int base;
2365 int ret, i;
2366
2367 gsm->tty = tty_kref_get(tty);
2368 gsm->output = gsmld_output;
2369 ret = gsm_activate_mux(gsm);
2370 if (ret != 0)
2371 tty_kref_put(gsm->tty);
2372 else {
2373 /* Don't register device 0 - this is the control channel and not
2374 a usable tty interface */
2375 base = mux_num_to_base(gsm); /* Base for this MUX */
2376 for (i = 1; i < NUM_DLCI; i++)
2377 tty_register_device(gsm_tty_driver, base + i, NULL);
2378 }
2379 return ret;
2380}
2381
2382
2383/**
2384 * gsmld_detach_gsm - stop doing 0710 mux
2385 * @tty: tty attached to the mux
2386 * @gsm: mux
2387 *
2388 * Shutdown and then clean up the resources used by the line discipline
2389 */
2390
2391static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2392{
2393 unsigned int base = mux_num_to_base(gsm); /* Base for this MUX */
2394 int i;
2395
2396 WARN_ON(tty != gsm->tty);
2397 for (i = 1; i < NUM_DLCI; i++)
2398 tty_unregister_device(gsm_tty_driver, base + i);
2399 gsm_cleanup_mux(gsm);
2400 tty_kref_put(gsm->tty);
2401 gsm->tty = NULL;
2402}
2403
2404static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
2405 char *fp, int count)
2406{
2407 struct gsm_mux *gsm = tty->disc_data;
2408 const unsigned char *dp;
2409 char *f;
2410 int i;
2411 char flags = TTY_NORMAL;
2412
2413 if (debug & 4)
2414 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET,
2415 cp, count);
2416
2417 for (i = count, dp = cp, f = fp; i; i--, dp++) {
2418 if (f)
2419 flags = *f++;
2420 switch (flags) {
2421 case TTY_NORMAL:
2422 gsm->receive(gsm, *dp);
2423 break;
2424 case TTY_OVERRUN:
2425 case TTY_BREAK:
2426 case TTY_PARITY:
2427 case TTY_FRAME:
2428 gsm->error(gsm, *dp, flags);
2429 break;
2430 default:
2431 WARN_ONCE(1, "%s: unknown flag %d\n",
2432 tty_name(tty), flags);
2433 break;
2434 }
2435 }
2436 /* FASYNC if needed ? */
2437 /* If clogged call tty_throttle(tty); */
2438}
2439
2440/**
2441 * gsmld_flush_buffer - clean input queue
2442 * @tty: terminal device
2443 *
2444 * Flush the input buffer. Called when the line discipline is
2445 * being closed, when the tty layer wants the buffer flushed (eg
2446 * at hangup).
2447 */
2448
2449static void gsmld_flush_buffer(struct tty_struct *tty)
2450{
2451}
2452
2453/**
2454 * gsmld_close - close the ldisc for this tty
2455 * @tty: device
2456 *
2457 * Called from the terminal layer when this line discipline is
2458 * being shut down, either because of a close or becsuse of a
2459 * discipline change. The function will not be called while other
2460 * ldisc methods are in progress.
2461 */
2462
2463static void gsmld_close(struct tty_struct *tty)
2464{
2465 struct gsm_mux *gsm = tty->disc_data;
2466
2467 gsmld_detach_gsm(tty, gsm);
2468
2469 gsmld_flush_buffer(tty);
2470 /* Do other clean up here */
2471 mux_put(gsm);
2472}
2473
2474/**
2475 * gsmld_open - open an ldisc
2476 * @tty: terminal to open
2477 *
2478 * Called when this line discipline is being attached to the
2479 * terminal device. Can sleep. Called serialized so that no
2480 * other events will occur in parallel. No further open will occur
2481 * until a close.
2482 */
2483
2484static int gsmld_open(struct tty_struct *tty)
2485{
2486 struct gsm_mux *gsm;
2487 int ret;
2488
2489 if (tty->ops->write == NULL)
2490 return -EINVAL;
2491
2492 /* Attach our ldisc data */
2493 gsm = gsm_alloc_mux();
2494 if (gsm == NULL)
2495 return -ENOMEM;
2496
2497 tty->disc_data = gsm;
2498 tty->receive_room = 65536;
2499
2500 /* Attach the initial passive connection */
2501 gsm->encoding = 1;
2502
2503 ret = gsmld_attach_gsm(tty, gsm);
2504 if (ret != 0) {
2505 gsm_cleanup_mux(gsm);
2506 mux_put(gsm);
2507 }
2508 return ret;
2509}
2510
2511/**
2512 * gsmld_write_wakeup - asynchronous I/O notifier
2513 * @tty: tty device
2514 *
2515 * Required for the ptys, serial driver etc. since processes
2516 * that attach themselves to the master and rely on ASYNC
2517 * IO must be woken up
2518 */
2519
2520static void gsmld_write_wakeup(struct tty_struct *tty)
2521{
2522 struct gsm_mux *gsm = tty->disc_data;
2523 unsigned long flags;
2524
2525 /* Queue poll */
2526 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2527 spin_lock_irqsave(&gsm->tx_lock, flags);
2528 gsm_data_kick(gsm);
2529 if (gsm->tx_bytes < TX_THRESH_LO) {
2530 gsm_dlci_data_sweep(gsm);
2531 }
2532 spin_unlock_irqrestore(&gsm->tx_lock, flags);
2533}
2534
2535/**
2536 * gsmld_read - read function for tty
2537 * @tty: tty device
2538 * @file: file object
2539 * @buf: userspace buffer pointer
2540 * @nr: size of I/O
2541 *
2542 * Perform reads for the line discipline. We are guaranteed that the
2543 * line discipline will not be closed under us but we may get multiple
2544 * parallel readers and must handle this ourselves. We may also get
2545 * a hangup. Always called in user context, may sleep.
2546 *
2547 * This code must be sure never to sleep through a hangup.
2548 */
2549
2550static ssize_t gsmld_read(struct tty_struct *tty, struct file *file,
2551 unsigned char __user *buf, size_t nr)
2552{
2553 return -EOPNOTSUPP;
2554}
2555
2556/**
2557 * gsmld_write - write function for tty
2558 * @tty: tty device
2559 * @file: file object
2560 * @buf: userspace buffer pointer
2561 * @nr: size of I/O
2562 *
2563 * Called when the owner of the device wants to send a frame
2564 * itself (or some other control data). The data is transferred
2565 * as-is and must be properly framed and checksummed as appropriate
2566 * by userspace. Frames are either sent whole or not at all as this
2567 * avoids pain user side.
2568 */
2569
2570static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
2571 const unsigned char *buf, size_t nr)
2572{
2573 int space = tty_write_room(tty);
2574 if (space >= nr)
2575 return tty->ops->write(tty, buf, nr);
2576 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2577 return -ENOBUFS;
2578}
2579
2580/**
2581 * gsmld_poll - poll method for N_GSM0710
2582 * @tty: terminal device
2583 * @file: file accessing it
2584 * @wait: poll table
2585 *
2586 * Called when the line discipline is asked to poll() for data or
2587 * for special events. This code is not serialized with respect to
2588 * other events save open/close.
2589 *
2590 * This code must be sure never to sleep through a hangup.
2591 * Called without the kernel lock held - fine
2592 */
2593
2594static __poll_t gsmld_poll(struct tty_struct *tty, struct file *file,
2595 poll_table *wait)
2596{
2597 __poll_t mask = 0;
2598 struct gsm_mux *gsm = tty->disc_data;
2599
2600 poll_wait(file, &tty->read_wait, wait);
2601 poll_wait(file, &tty->write_wait, wait);
2602 if (tty_hung_up_p(file))
2603 mask |= EPOLLHUP;
2604 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
2605 mask |= EPOLLOUT | EPOLLWRNORM;
2606 if (gsm->dead)
2607 mask |= EPOLLHUP;
2608 return mask;
2609}
2610
2611static int gsmld_ioctl(struct tty_struct *tty, struct file *file,
2612 unsigned int cmd, unsigned long arg)
2613{
2614 struct gsm_config c;
2615 struct gsm_mux *gsm = tty->disc_data;
2616 unsigned int base;
2617
2618 switch (cmd) {
2619 case GSMIOC_GETCONF:
2620 gsm_copy_config_values(gsm, &c);
2621 if (copy_to_user((void *)arg, &c, sizeof(c)))
2622 return -EFAULT;
2623 return 0;
2624 case GSMIOC_SETCONF:
2625 if (copy_from_user(&c, (void *)arg, sizeof(c)))
2626 return -EFAULT;
2627 return gsm_config(gsm, &c);
2628 case GSMIOC_GETFIRST:
2629 base = mux_num_to_base(gsm);
2630 return put_user(base + 1, (__u32 __user *)arg);
2631 default:
2632 return n_tty_ioctl_helper(tty, file, cmd, arg);
2633 }
2634}
2635
2636/*
2637 * Network interface
2638 *
2639 */
2640
2641static int gsm_mux_net_open(struct net_device *net)
2642{
2643 pr_debug("%s called\n", __func__);
2644 netif_start_queue(net);
2645 return 0;
2646}
2647
2648static int gsm_mux_net_close(struct net_device *net)
2649{
2650 netif_stop_queue(net);
2651 return 0;
2652}
2653
2654static void dlci_net_free(struct gsm_dlci *dlci)
2655{
2656 if (!dlci->net) {
2657 WARN_ON(1);
2658 return;
2659 }
2660 dlci->adaption = dlci->prev_adaption;
2661 dlci->data = dlci->prev_data;
2662 free_netdev(dlci->net);
2663 dlci->net = NULL;
2664}
2665static void net_free(struct kref *ref)
2666{
2667 struct gsm_mux_net *mux_net;
2668 struct gsm_dlci *dlci;
2669
2670 mux_net = container_of(ref, struct gsm_mux_net, ref);
2671 dlci = mux_net->dlci;
2672
2673 if (dlci->net) {
2674 unregister_netdev(dlci->net);
2675 dlci_net_free(dlci);
2676 }
2677}
2678
2679static inline void muxnet_get(struct gsm_mux_net *mux_net)
2680{
2681 kref_get(&mux_net->ref);
2682}
2683
2684static inline void muxnet_put(struct gsm_mux_net *mux_net)
2685{
2686 kref_put(&mux_net->ref, net_free);
2687}
2688
2689static netdev_tx_t gsm_mux_net_start_xmit(struct sk_buff *skb,
2690 struct net_device *net)
2691{
2692 struct gsm_mux_net *mux_net = netdev_priv(net);
2693 struct gsm_dlci *dlci = mux_net->dlci;
2694 muxnet_get(mux_net);
2695
2696 skb_queue_head(&dlci->skb_list, skb);
2697 net->stats.tx_packets++;
2698 net->stats.tx_bytes += skb->len;
2699 gsm_dlci_data_kick(dlci);
2700 /* And tell the kernel when the last transmit started. */
2701 netif_trans_update(net);
2702 muxnet_put(mux_net);
2703 return NETDEV_TX_OK;
2704}
2705
2706/* called when a packet did not ack after watchdogtimeout */
2707static void gsm_mux_net_tx_timeout(struct net_device *net)
2708{
2709 /* Tell syslog we are hosed. */
2710 dev_dbg(&net->dev, "Tx timed out.\n");
2711
2712 /* Update statistics */
2713 net->stats.tx_errors++;
2714}
2715
2716static void gsm_mux_rx_netchar(struct gsm_dlci *dlci,
2717 const unsigned char *in_buf, int size)
2718{
2719 struct net_device *net = dlci->net;
2720 struct sk_buff *skb;
2721 struct gsm_mux_net *mux_net = netdev_priv(net);
2722 muxnet_get(mux_net);
2723
2724 /* Allocate an sk_buff */
2725 skb = dev_alloc_skb(size + NET_IP_ALIGN);
2726 if (!skb) {
2727 /* We got no receive buffer. */
2728 net->stats.rx_dropped++;
2729 muxnet_put(mux_net);
2730 return;
2731 }
2732 skb_reserve(skb, NET_IP_ALIGN);
2733 skb_put_data(skb, in_buf, size);
2734
2735 skb->dev = net;
2736 skb->protocol = htons(ETH_P_IP);
2737
2738 /* Ship it off to the kernel */
2739 netif_rx(skb);
2740
2741 /* update out statistics */
2742 net->stats.rx_packets++;
2743 net->stats.rx_bytes += size;
2744 muxnet_put(mux_net);
2745 return;
2746}
2747
2748static void gsm_mux_net_init(struct net_device *net)
2749{
2750 static const struct net_device_ops gsm_netdev_ops = {
2751 .ndo_open = gsm_mux_net_open,
2752 .ndo_stop = gsm_mux_net_close,
2753 .ndo_start_xmit = gsm_mux_net_start_xmit,
2754 .ndo_tx_timeout = gsm_mux_net_tx_timeout,
2755 };
2756
2757 net->netdev_ops = &gsm_netdev_ops;
2758
2759 /* fill in the other fields */
2760 net->watchdog_timeo = GSM_NET_TX_TIMEOUT;
2761 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
2762 net->type = ARPHRD_NONE;
2763 net->tx_queue_len = 10;
2764}
2765
2766
2767/* caller holds the dlci mutex */
2768static void gsm_destroy_network(struct gsm_dlci *dlci)
2769{
2770 struct gsm_mux_net *mux_net;
2771
2772 pr_debug("destroy network interface");
2773 if (!dlci->net)
2774 return;
2775 mux_net = netdev_priv(dlci->net);
2776 muxnet_put(mux_net);
2777}
2778
2779
2780/* caller holds the dlci mutex */
2781static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
2782{
2783 char *netname;
2784 int retval = 0;
2785 struct net_device *net;
2786 struct gsm_mux_net *mux_net;
2787
2788 if (!capable(CAP_NET_ADMIN))
2789 return -EPERM;
2790
2791 /* Already in a non tty mode */
2792 if (dlci->adaption > 2)
2793 return -EBUSY;
2794
2795 if (nc->protocol != htons(ETH_P_IP))
2796 return -EPROTONOSUPPORT;
2797
2798 if (nc->adaption != 3 && nc->adaption != 4)
2799 return -EPROTONOSUPPORT;
2800
2801 pr_debug("create network interface");
2802
2803 netname = "gsm%d";
2804 if (nc->if_name[0] != '\0')
2805 netname = nc->if_name;
2806 net = alloc_netdev(sizeof(struct gsm_mux_net), netname,
2807 NET_NAME_UNKNOWN, gsm_mux_net_init);
2808 if (!net) {
2809 pr_err("alloc_netdev failed");
2810 return -ENOMEM;
2811 }
2812 net->mtu = dlci->gsm->mtu;
2813 net->min_mtu = 8;
2814 net->max_mtu = dlci->gsm->mtu;
2815 mux_net = netdev_priv(net);
2816 mux_net->dlci = dlci;
2817 kref_init(&mux_net->ref);
2818 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */
2819
2820 /* reconfigure dlci for network */
2821 dlci->prev_adaption = dlci->adaption;
2822 dlci->prev_data = dlci->data;
2823 dlci->adaption = nc->adaption;
2824 dlci->data = gsm_mux_rx_netchar;
2825 dlci->net = net;
2826
2827 pr_debug("register netdev");
2828 retval = register_netdev(net);
2829 if (retval) {
2830 pr_err("network register fail %d\n", retval);
2831 dlci_net_free(dlci);
2832 return retval;
2833 }
2834 return net->ifindex; /* return network index */
2835}
2836
2837/* Line discipline for real tty */
2838static struct tty_ldisc_ops tty_ldisc_packet = {
2839 .owner = THIS_MODULE,
2840 .magic = TTY_LDISC_MAGIC,
2841 .name = "n_gsm",
2842 .open = gsmld_open,
2843 .close = gsmld_close,
2844 .flush_buffer = gsmld_flush_buffer,
2845 .read = gsmld_read,
2846 .write = gsmld_write,
2847 .ioctl = gsmld_ioctl,
2848 .poll = gsmld_poll,
2849 .receive_buf = gsmld_receive_buf,
2850 .write_wakeup = gsmld_write_wakeup
2851};
2852
2853/*
2854 * Virtual tty side
2855 */
2856
2857#define TX_SIZE 512
2858
2859static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk)
2860{
2861 u8 modembits[5];
2862 struct gsm_control *ctrl;
2863 int len = 2;
2864
2865 if (brk)
2866 len++;
2867
2868 modembits[0] = len << 1 | EA; /* Data bytes */
2869 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */
2870 modembits[2] = gsm_encode_modem(dlci) << 1 | EA;
2871 if (brk)
2872 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */
2873 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1);
2874 if (ctrl == NULL)
2875 return -ENOMEM;
2876 return gsm_control_wait(dlci->gsm, ctrl);
2877}
2878
2879static int gsm_carrier_raised(struct tty_port *port)
2880{
2881 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2882 struct gsm_mux *gsm = dlci->gsm;
2883
2884 /* Not yet open so no carrier info */
2885 if (dlci->state != DLCI_OPEN)
2886 return 0;
2887 if (debug & 2)
2888 return 1;
2889
2890 /*
2891 * Basic mode with control channel in ADM mode may not respond
2892 * to CMD_MSC at all and modem_rx is empty.
2893 */
2894 if (gsm->encoding == 0 && gsm->dlci[0]->mode == DLCI_MODE_ADM &&
2895 !dlci->modem_rx)
2896 return 1;
2897
2898 return dlci->modem_rx & TIOCM_CD;
2899}
2900
2901static void gsm_dtr_rts(struct tty_port *port, int onoff)
2902{
2903 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2904 unsigned int modem_tx = dlci->modem_tx;
2905 if (onoff)
2906 modem_tx |= TIOCM_DTR | TIOCM_RTS;
2907 else
2908 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
2909 if (modem_tx != dlci->modem_tx) {
2910 dlci->modem_tx = modem_tx;
2911 gsmtty_modem_update(dlci, 0);
2912 }
2913}
2914
2915static const struct tty_port_operations gsm_port_ops = {
2916 .carrier_raised = gsm_carrier_raised,
2917 .dtr_rts = gsm_dtr_rts,
2918 .destruct = gsm_dlci_free,
2919};
2920
2921static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty)
2922{
2923 struct gsm_mux *gsm;
2924 struct gsm_dlci *dlci;
2925 unsigned int line = tty->index;
2926 unsigned int mux = mux_line_to_num(line);
2927 bool alloc = false;
2928 int ret;
2929
2930 line = line & 0x3F;
2931
2932 if (mux >= MAX_MUX)
2933 return -ENXIO;
2934 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
2935 if (gsm_mux[mux] == NULL)
2936 return -EUNATCH;
2937 if (line == 0 || line > 61) /* 62/63 reserved */
2938 return -ECHRNG;
2939 gsm = gsm_mux[mux];
2940 if (gsm->dead)
2941 return -EL2HLT;
2942 /* If DLCI 0 is not yet fully open return an error.
2943 This is ok from a locking
2944 perspective as we don't have to worry about this
2945 if DLCI0 is lost */
2946 mutex_lock(&gsm->mutex);
2947 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN) {
2948 mutex_unlock(&gsm->mutex);
2949 return -EL2NSYNC;
2950 }
2951 dlci = gsm->dlci[line];
2952 if (dlci == NULL) {
2953 alloc = true;
2954 dlci = gsm_dlci_alloc(gsm, line);
2955 }
2956 if (dlci == NULL) {
2957 mutex_unlock(&gsm->mutex);
2958 return -ENOMEM;
2959 }
2960 ret = tty_port_install(&dlci->port, driver, tty);
2961 if (ret) {
2962 if (alloc)
2963 dlci_put(dlci);
2964 mutex_unlock(&gsm->mutex);
2965 return ret;
2966 }
2967
2968 dlci_get(dlci);
2969 dlci_get(gsm->dlci[0]);
2970 mux_get(gsm);
2971 tty->driver_data = dlci;
2972 mutex_unlock(&gsm->mutex);
2973
2974 return 0;
2975}
2976
2977static int gsmtty_open(struct tty_struct *tty, struct file *filp)
2978{
2979 struct gsm_dlci *dlci = tty->driver_data;
2980 struct tty_port *port = &dlci->port;
2981
2982 port->count++;
2983 tty_port_tty_set(port, tty);
2984
2985 dlci->modem_rx = 0;
2986 /* We could in theory open and close before we wait - eg if we get
2987 a DM straight back. This is ok as that will have caused a hangup */
2988 tty_port_set_initialized(port, 1);
2989 /* Start sending off SABM messages */
2990 gsm_dlci_begin_open(dlci);
2991 /* And wait for virtual carrier */
2992 return tty_port_block_til_ready(port, tty, filp);
2993}
2994
2995static void gsmtty_close(struct tty_struct *tty, struct file *filp)
2996{
2997 struct gsm_dlci *dlci = tty->driver_data;
2998
2999 if (dlci == NULL)
3000 return;
3001 if (dlci->state == DLCI_CLOSED)
3002 return;
3003 mutex_lock(&dlci->mutex);
3004 gsm_destroy_network(dlci);
3005 mutex_unlock(&dlci->mutex);
3006 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
3007 return;
3008 gsm_dlci_begin_close(dlci);
3009 if (tty_port_initialized(&dlci->port) && C_HUPCL(tty))
3010 tty_port_lower_dtr_rts(&dlci->port);
3011 tty_port_close_end(&dlci->port, tty);
3012 tty_port_tty_set(&dlci->port, NULL);
3013 return;
3014}
3015
3016static void gsmtty_hangup(struct tty_struct *tty)
3017{
3018 struct gsm_dlci *dlci = tty->driver_data;
3019 if (dlci->state == DLCI_CLOSED)
3020 return;
3021 tty_port_hangup(&dlci->port);
3022 gsm_dlci_begin_close(dlci);
3023}
3024
3025static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf,
3026 int len)
3027{
3028 int sent;
3029 struct gsm_dlci *dlci = tty->driver_data;
3030 if (dlci->state == DLCI_CLOSED)
3031 return -EINVAL;
3032 /* Stuff the bytes into the fifo queue */
3033 sent = kfifo_in_locked(dlci->fifo, buf, len, &dlci->lock);
3034 /* Need to kick the channel */
3035 gsm_dlci_data_kick(dlci);
3036 return sent;
3037}
3038
3039static int gsmtty_write_room(struct tty_struct *tty)
3040{
3041 struct gsm_dlci *dlci = tty->driver_data;
3042 if (dlci->state == DLCI_CLOSED)
3043 return -EINVAL;
3044 return TX_SIZE - kfifo_len(dlci->fifo);
3045}
3046
3047static int gsmtty_chars_in_buffer(struct tty_struct *tty)
3048{
3049 struct gsm_dlci *dlci = tty->driver_data;
3050 if (dlci->state == DLCI_CLOSED)
3051 return -EINVAL;
3052 return kfifo_len(dlci->fifo);
3053}
3054
3055static void gsmtty_flush_buffer(struct tty_struct *tty)
3056{
3057 struct gsm_dlci *dlci = tty->driver_data;
3058 if (dlci->state == DLCI_CLOSED)
3059 return;
3060 /* Caution needed: If we implement reliable transport classes
3061 then the data being transmitted can't simply be junked once
3062 it has first hit the stack. Until then we can just blow it
3063 away */
3064 kfifo_reset(dlci->fifo);
3065 /* Need to unhook this DLCI from the transmit queue logic */
3066}
3067
3068static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
3069{
3070 /* The FIFO handles the queue so the kernel will do the right
3071 thing waiting on chars_in_buffer before calling us. No work
3072 to do here */
3073}
3074
3075static int gsmtty_tiocmget(struct tty_struct *tty)
3076{
3077 struct gsm_dlci *dlci = tty->driver_data;
3078 if (dlci->state == DLCI_CLOSED)
3079 return -EINVAL;
3080 return dlci->modem_rx;
3081}
3082
3083static int gsmtty_tiocmset(struct tty_struct *tty,
3084 unsigned int set, unsigned int clear)
3085{
3086 struct gsm_dlci *dlci = tty->driver_data;
3087 unsigned int modem_tx = dlci->modem_tx;
3088
3089 if (dlci->state == DLCI_CLOSED)
3090 return -EINVAL;
3091 modem_tx &= ~clear;
3092 modem_tx |= set;
3093
3094 if (modem_tx != dlci->modem_tx) {
3095 dlci->modem_tx = modem_tx;
3096 return gsmtty_modem_update(dlci, 0);
3097 }
3098 return 0;
3099}
3100
3101
3102static int gsmtty_ioctl(struct tty_struct *tty,
3103 unsigned int cmd, unsigned long arg)
3104{
3105 struct gsm_dlci *dlci = tty->driver_data;
3106 struct gsm_netconfig nc;
3107 int index;
3108
3109 if (dlci->state == DLCI_CLOSED)
3110 return -EINVAL;
3111 switch (cmd) {
3112 case GSMIOC_ENABLE_NET:
3113 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc)))
3114 return -EFAULT;
3115 nc.if_name[IFNAMSIZ-1] = '\0';
3116 /* return net interface index or error code */
3117 mutex_lock(&dlci->mutex);
3118 index = gsm_create_network(dlci, &nc);
3119 mutex_unlock(&dlci->mutex);
3120 if (copy_to_user((void __user *)arg, &nc, sizeof(nc)))
3121 return -EFAULT;
3122 return index;
3123 case GSMIOC_DISABLE_NET:
3124 if (!capable(CAP_NET_ADMIN))
3125 return -EPERM;
3126 mutex_lock(&dlci->mutex);
3127 gsm_destroy_network(dlci);
3128 mutex_unlock(&dlci->mutex);
3129 return 0;
3130 default:
3131 return -ENOIOCTLCMD;
3132 }
3133}
3134
3135static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old)
3136{
3137 struct gsm_dlci *dlci = tty->driver_data;
3138 if (dlci->state == DLCI_CLOSED)
3139 return;
3140 /* For the moment its fixed. In actual fact the speed information
3141 for the virtual channel can be propogated in both directions by
3142 the RPN control message. This however rapidly gets nasty as we
3143 then have to remap modem signals each way according to whether
3144 our virtual cable is null modem etc .. */
3145 tty_termios_copy_hw(&tty->termios, old);
3146}
3147
3148static void gsmtty_throttle(struct tty_struct *tty)
3149{
3150 struct gsm_dlci *dlci = tty->driver_data;
3151 if (dlci->state == DLCI_CLOSED)
3152 return;
3153 if (C_CRTSCTS(tty))
3154 dlci->modem_tx &= ~TIOCM_DTR;
3155 dlci->throttled = 1;
3156 /* Send an MSC with DTR cleared */
3157 gsmtty_modem_update(dlci, 0);
3158}
3159
3160static void gsmtty_unthrottle(struct tty_struct *tty)
3161{
3162 struct gsm_dlci *dlci = tty->driver_data;
3163 if (dlci->state == DLCI_CLOSED)
3164 return;
3165 if (C_CRTSCTS(tty))
3166 dlci->modem_tx |= TIOCM_DTR;
3167 dlci->throttled = 0;
3168 /* Send an MSC with DTR set */
3169 gsmtty_modem_update(dlci, 0);
3170}
3171
3172static int gsmtty_break_ctl(struct tty_struct *tty, int state)
3173{
3174 struct gsm_dlci *dlci = tty->driver_data;
3175 int encode = 0; /* Off */
3176 if (dlci->state == DLCI_CLOSED)
3177 return -EINVAL;
3178
3179 if (state == -1) /* "On indefinitely" - we can't encode this
3180 properly */
3181 encode = 0x0F;
3182 else if (state > 0) {
3183 encode = state / 200; /* mS to encoding */
3184 if (encode > 0x0F)
3185 encode = 0x0F; /* Best effort */
3186 }
3187 return gsmtty_modem_update(dlci, encode);
3188}
3189
3190static void gsmtty_cleanup(struct tty_struct *tty)
3191{
3192 struct gsm_dlci *dlci = tty->driver_data;
3193 struct gsm_mux *gsm = dlci->gsm;
3194
3195 dlci_put(dlci);
3196 dlci_put(gsm->dlci[0]);
3197 mux_put(gsm);
3198}
3199
3200/* Virtual ttys for the demux */
3201static const struct tty_operations gsmtty_ops = {
3202 .install = gsmtty_install,
3203 .open = gsmtty_open,
3204 .close = gsmtty_close,
3205 .write = gsmtty_write,
3206 .write_room = gsmtty_write_room,
3207 .chars_in_buffer = gsmtty_chars_in_buffer,
3208 .flush_buffer = gsmtty_flush_buffer,
3209 .ioctl = gsmtty_ioctl,
3210 .throttle = gsmtty_throttle,
3211 .unthrottle = gsmtty_unthrottle,
3212 .set_termios = gsmtty_set_termios,
3213 .hangup = gsmtty_hangup,
3214 .wait_until_sent = gsmtty_wait_until_sent,
3215 .tiocmget = gsmtty_tiocmget,
3216 .tiocmset = gsmtty_tiocmset,
3217 .break_ctl = gsmtty_break_ctl,
3218 .cleanup = gsmtty_cleanup,
3219};
3220
3221
3222
3223static int __init gsm_init(void)
3224{
3225 /* Fill in our line protocol discipline, and register it */
3226 int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet);
3227 if (status != 0) {
3228 pr_err("n_gsm: can't register line discipline (err = %d)\n",
3229 status);
3230 return status;
3231 }
3232
3233 gsm_tty_driver = alloc_tty_driver(256);
3234 if (!gsm_tty_driver) {
3235 tty_unregister_ldisc(N_GSM0710);
3236 pr_err("gsm_init: tty allocation failed.\n");
3237 return -EINVAL;
3238 }
3239 gsm_tty_driver->driver_name = "gsmtty";
3240 gsm_tty_driver->name = "gsmtty";
3241 gsm_tty_driver->major = 0; /* Dynamic */
3242 gsm_tty_driver->minor_start = 0;
3243 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
3244 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
3245 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV
3246 | TTY_DRIVER_HARDWARE_BREAK;
3247 gsm_tty_driver->init_termios = tty_std_termios;
3248 /* Fixme */
3249 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
3250 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
3251
3252 spin_lock_init(&gsm_mux_lock);
3253
3254 if (tty_register_driver(gsm_tty_driver)) {
3255 put_tty_driver(gsm_tty_driver);
3256 tty_unregister_ldisc(N_GSM0710);
3257 pr_err("gsm_init: tty registration failed.\n");
3258 return -EBUSY;
3259 }
3260 pr_debug("gsm_init: loaded as %d,%d.\n",
3261 gsm_tty_driver->major, gsm_tty_driver->minor_start);
3262 return 0;
3263}
3264
3265static void __exit gsm_exit(void)
3266{
3267 int status = tty_unregister_ldisc(N_GSM0710);
3268 if (status != 0)
3269 pr_err("n_gsm: can't unregister line discipline (err = %d)\n",
3270 status);
3271 tty_unregister_driver(gsm_tty_driver);
3272 put_tty_driver(gsm_tty_driver);
3273}
3274
3275module_init(gsm_init);
3276module_exit(gsm_exit);
3277
3278
3279MODULE_LICENSE("GPL");
3280MODULE_ALIAS_LDISC(N_GSM0710);
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 * Improve the tx engine
25 * Resolve tx side locking by adding a queue_head and routing
26 * all control traffic via it
27 * General tidy/document
28 * Review the locking/move to refcounts more (mux now moved to an
29 * alloc/free model ready)
30 * Use newest tty open/close port helpers and install hooks
31 * What to do about power functions ?
32 * Termios setting and negotiation
33 * Do we need a 'which mux are you' ioctl to correlate mux and tty sets
34 *
35 */
36
37#include <linux/types.h>
38#include <linux/major.h>
39#include <linux/errno.h>
40#include <linux/signal.h>
41#include <linux/fcntl.h>
42#include <linux/sched.h>
43#include <linux/interrupt.h>
44#include <linux/tty.h>
45#include <linux/ctype.h>
46#include <linux/mm.h>
47#include <linux/string.h>
48#include <linux/slab.h>
49#include <linux/poll.h>
50#include <linux/bitops.h>
51#include <linux/file.h>
52#include <linux/uaccess.h>
53#include <linux/module.h>
54#include <linux/timer.h>
55#include <linux/tty_flip.h>
56#include <linux/tty_driver.h>
57#include <linux/serial.h>
58#include <linux/kfifo.h>
59#include <linux/skbuff.h>
60#include <net/arp.h>
61#include <linux/ip.h>
62#include <linux/netdevice.h>
63#include <linux/etherdevice.h>
64#include <linux/gsmmux.h>
65
66static int debug;
67module_param(debug, int, 0600);
68
69/* Defaults: these are from the specification */
70
71#define T1 10 /* 100mS */
72#define T2 34 /* 333mS */
73#define N2 3 /* Retry 3 times */
74
75/* Use long timers for testing at low speed with debug on */
76#ifdef DEBUG_TIMING
77#define T1 100
78#define T2 200
79#endif
80
81/*
82 * Semi-arbitrary buffer size limits. 0710 is normally run with 32-64 byte
83 * limits so this is plenty
84 */
85#define MAX_MRU 1500
86#define MAX_MTU 1500
87#define GSM_NET_TX_TIMEOUT (HZ*10)
88
89/**
90 * struct gsm_mux_net - network interface
91 * @struct gsm_dlci* dlci
92 * @struct net_device_stats stats;
93 *
94 * Created when net interface is initialized.
95 **/
96struct gsm_mux_net {
97 struct kref ref;
98 struct gsm_dlci *dlci;
99 struct net_device_stats stats;
100};
101
102#define STATS(net) (((struct gsm_mux_net *)netdev_priv(net))->stats)
103
104/*
105 * Each block of data we have queued to go out is in the form of
106 * a gsm_msg which holds everything we need in a link layer independent
107 * format
108 */
109
110struct gsm_msg {
111 struct gsm_msg *next;
112 u8 addr; /* DLCI address + flags */
113 u8 ctrl; /* Control byte + flags */
114 unsigned int len; /* Length of data block (can be zero) */
115 unsigned char *data; /* Points into buffer but not at the start */
116 unsigned char buffer[0];
117};
118
119/*
120 * Each active data link has a gsm_dlci structure associated which ties
121 * the link layer to an optional tty (if the tty side is open). To avoid
122 * complexity right now these are only ever freed up when the mux is
123 * shut down.
124 *
125 * At the moment we don't free DLCI objects until the mux is torn down
126 * this avoid object life time issues but might be worth review later.
127 */
128
129struct gsm_dlci {
130 struct gsm_mux *gsm;
131 int addr;
132 int state;
133#define DLCI_CLOSED 0
134#define DLCI_OPENING 1 /* Sending SABM not seen UA */
135#define DLCI_OPEN 2 /* SABM/UA complete */
136#define DLCI_CLOSING 3 /* Sending DISC not seen UA/DM */
137 struct kref ref; /* freed from port or mux close */
138 struct mutex mutex;
139
140 /* Link layer */
141 spinlock_t lock; /* Protects the internal state */
142 struct timer_list t1; /* Retransmit timer for SABM and UA */
143 int retries;
144 /* Uplink tty if active */
145 struct tty_port port; /* The tty bound to this DLCI if there is one */
146 struct kfifo *fifo; /* Queue fifo for the DLCI */
147 struct kfifo _fifo; /* For new fifo API porting only */
148 int adaption; /* Adaption layer in use */
149 int prev_adaption;
150 u32 modem_rx; /* Our incoming virtual modem lines */
151 u32 modem_tx; /* Our outgoing modem lines */
152 int dead; /* Refuse re-open */
153 /* Flow control */
154 int throttled; /* Private copy of throttle state */
155 int constipated; /* Throttle status for outgoing */
156 /* Packetised I/O */
157 struct sk_buff *skb; /* Frame being sent */
158 struct sk_buff_head skb_list; /* Queued frames */
159 /* Data handling callback */
160 void (*data)(struct gsm_dlci *dlci, u8 *data, int len);
161 void (*prev_data)(struct gsm_dlci *dlci, u8 *data, int len);
162 struct net_device *net; /* network interface, if created */
163};
164
165/* DLCI 0, 62/63 are special or reseved see gsmtty_open */
166
167#define NUM_DLCI 64
168
169/*
170 * DLCI 0 is used to pass control blocks out of band of the data
171 * flow (and with a higher link priority). One command can be outstanding
172 * at a time and we use this structure to manage them. They are created
173 * and destroyed by the user context, and updated by the receive paths
174 * and timers
175 */
176
177struct gsm_control {
178 u8 cmd; /* Command we are issuing */
179 u8 *data; /* Data for the command in case we retransmit */
180 int len; /* Length of block for retransmission */
181 int done; /* Done flag */
182 int error; /* Error if any */
183};
184
185/*
186 * Each GSM mux we have is represented by this structure. If we are
187 * operating as an ldisc then we use this structure as our ldisc
188 * state. We need to sort out lifetimes and locking with respect
189 * to the gsm mux array. For now we don't free DLCI objects that
190 * have been instantiated until the mux itself is terminated.
191 *
192 * To consider further: tty open versus mux shutdown.
193 */
194
195struct gsm_mux {
196 struct tty_struct *tty; /* The tty our ldisc is bound to */
197 spinlock_t lock;
198 unsigned int num;
199 struct kref ref;
200
201 /* Events on the GSM channel */
202 wait_queue_head_t event;
203
204 /* Bits for GSM mode decoding */
205
206 /* Framing Layer */
207 unsigned char *buf;
208 int state;
209#define GSM_SEARCH 0
210#define GSM_START 1
211#define GSM_ADDRESS 2
212#define GSM_CONTROL 3
213#define GSM_LEN 4
214#define GSM_DATA 5
215#define GSM_FCS 6
216#define GSM_OVERRUN 7
217#define GSM_LEN0 8
218#define GSM_LEN1 9
219#define GSM_SSOF 10
220 unsigned int len;
221 unsigned int address;
222 unsigned int count;
223 int escape;
224 int encoding;
225 u8 control;
226 u8 fcs;
227 u8 received_fcs;
228 u8 *txframe; /* TX framing buffer */
229
230 /* Methods for the receiver side */
231 void (*receive)(struct gsm_mux *gsm, u8 ch);
232 void (*error)(struct gsm_mux *gsm, u8 ch, u8 flag);
233 /* And transmit side */
234 int (*output)(struct gsm_mux *mux, u8 *data, int len);
235
236 /* Link Layer */
237 unsigned int mru;
238 unsigned int mtu;
239 int initiator; /* Did we initiate connection */
240 int dead; /* Has the mux been shut down */
241 struct gsm_dlci *dlci[NUM_DLCI];
242 int constipated; /* Asked by remote to shut up */
243
244 spinlock_t tx_lock;
245 unsigned int tx_bytes; /* TX data outstanding */
246#define TX_THRESH_HI 8192
247#define TX_THRESH_LO 2048
248 struct gsm_msg *tx_head; /* Pending data packets */
249 struct gsm_msg *tx_tail;
250
251 /* Control messages */
252 struct timer_list t2_timer; /* Retransmit timer for commands */
253 int cretries; /* Command retry counter */
254 struct gsm_control *pending_cmd;/* Our current pending command */
255 spinlock_t control_lock; /* Protects the pending command */
256
257 /* Configuration */
258 int adaption; /* 1 or 2 supported */
259 u8 ftype; /* UI or UIH */
260 int t1, t2; /* Timers in 1/100th of a sec */
261 int n2; /* Retry count */
262
263 /* Statistics (not currently exposed) */
264 unsigned long bad_fcs;
265 unsigned long malformed;
266 unsigned long io_error;
267 unsigned long bad_size;
268 unsigned long unsupported;
269};
270
271
272/*
273 * Mux objects - needed so that we can translate a tty index into the
274 * relevant mux and DLCI.
275 */
276
277#define MAX_MUX 4 /* 256 minors */
278static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */
279static spinlock_t gsm_mux_lock;
280
281static struct tty_driver *gsm_tty_driver;
282
283/*
284 * This section of the driver logic implements the GSM encodings
285 * both the basic and the 'advanced'. Reliable transport is not
286 * supported.
287 */
288
289#define CR 0x02
290#define EA 0x01
291#define PF 0x10
292
293/* I is special: the rest are ..*/
294#define RR 0x01
295#define UI 0x03
296#define RNR 0x05
297#define REJ 0x09
298#define DM 0x0F
299#define SABM 0x2F
300#define DISC 0x43
301#define UA 0x63
302#define UIH 0xEF
303
304/* Channel commands */
305#define CMD_NSC 0x09
306#define CMD_TEST 0x11
307#define CMD_PSC 0x21
308#define CMD_RLS 0x29
309#define CMD_FCOFF 0x31
310#define CMD_PN 0x41
311#define CMD_RPN 0x49
312#define CMD_FCON 0x51
313#define CMD_CLD 0x61
314#define CMD_SNC 0x69
315#define CMD_MSC 0x71
316
317/* Virtual modem bits */
318#define MDM_FC 0x01
319#define MDM_RTC 0x02
320#define MDM_RTR 0x04
321#define MDM_IC 0x20
322#define MDM_DV 0x40
323
324#define GSM0_SOF 0xF9
325#define GSM1_SOF 0x7E
326#define GSM1_ESCAPE 0x7D
327#define GSM1_ESCAPE_BITS 0x20
328#define XON 0x11
329#define XOFF 0x13
330
331static const struct tty_port_operations gsm_port_ops;
332
333/*
334 * CRC table for GSM 0710
335 */
336
337static const u8 gsm_fcs8[256] = {
338 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75,
339 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B,
340 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69,
341 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67,
342 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D,
343 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43,
344 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51,
345 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F,
346 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05,
347 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B,
348 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19,
349 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17,
350 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D,
351 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33,
352 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21,
353 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F,
354 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95,
355 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B,
356 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89,
357 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87,
358 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD,
359 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3,
360 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1,
361 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF,
362 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5,
363 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB,
364 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9,
365 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7,
366 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD,
367 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3,
368 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1,
369 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF
370};
371
372#define INIT_FCS 0xFF
373#define GOOD_FCS 0xCF
374
375/**
376 * gsm_fcs_add - update FCS
377 * @fcs: Current FCS
378 * @c: Next data
379 *
380 * Update the FCS to include c. Uses the algorithm in the specification
381 * notes.
382 */
383
384static inline u8 gsm_fcs_add(u8 fcs, u8 c)
385{
386 return gsm_fcs8[fcs ^ c];
387}
388
389/**
390 * gsm_fcs_add_block - update FCS for a block
391 * @fcs: Current FCS
392 * @c: buffer of data
393 * @len: length of buffer
394 *
395 * Update the FCS to include c. Uses the algorithm in the specification
396 * notes.
397 */
398
399static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len)
400{
401 while (len--)
402 fcs = gsm_fcs8[fcs ^ *c++];
403 return fcs;
404}
405
406/**
407 * gsm_read_ea - read a byte into an EA
408 * @val: variable holding value
409 * c: byte going into the EA
410 *
411 * Processes one byte of an EA. Updates the passed variable
412 * and returns 1 if the EA is now completely read
413 */
414
415static int gsm_read_ea(unsigned int *val, u8 c)
416{
417 /* Add the next 7 bits into the value */
418 *val <<= 7;
419 *val |= c >> 1;
420 /* Was this the last byte of the EA 1 = yes*/
421 return c & EA;
422}
423
424/**
425 * gsm_encode_modem - encode modem data bits
426 * @dlci: DLCI to encode from
427 *
428 * Returns the correct GSM encoded modem status bits (6 bit field) for
429 * the current status of the DLCI and attached tty object
430 */
431
432static u8 gsm_encode_modem(const struct gsm_dlci *dlci)
433{
434 u8 modembits = 0;
435 /* FC is true flow control not modem bits */
436 if (dlci->throttled)
437 modembits |= MDM_FC;
438 if (dlci->modem_tx & TIOCM_DTR)
439 modembits |= MDM_RTC;
440 if (dlci->modem_tx & TIOCM_RTS)
441 modembits |= MDM_RTR;
442 if (dlci->modem_tx & TIOCM_RI)
443 modembits |= MDM_IC;
444 if (dlci->modem_tx & TIOCM_CD)
445 modembits |= MDM_DV;
446 return modembits;
447}
448
449/**
450 * gsm_print_packet - display a frame for debug
451 * @hdr: header to print before decode
452 * @addr: address EA from the frame
453 * @cr: C/R bit from the frame
454 * @control: control including PF bit
455 * @data: following data bytes
456 * @dlen: length of data
457 *
458 * Displays a packet in human readable format for debugging purposes. The
459 * style is based on amateur radio LAP-B dump display.
460 */
461
462static void gsm_print_packet(const char *hdr, int addr, int cr,
463 u8 control, const u8 *data, int dlen)
464{
465 if (!(debug & 1))
466 return;
467
468 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]);
469
470 switch (control & ~PF) {
471 case SABM:
472 pr_cont("SABM");
473 break;
474 case UA:
475 pr_cont("UA");
476 break;
477 case DISC:
478 pr_cont("DISC");
479 break;
480 case DM:
481 pr_cont("DM");
482 break;
483 case UI:
484 pr_cont("UI");
485 break;
486 case UIH:
487 pr_cont("UIH");
488 break;
489 default:
490 if (!(control & 0x01)) {
491 pr_cont("I N(S)%d N(R)%d",
492 (control & 0x0E) >> 1, (control & 0xE) >> 5);
493 } else switch (control & 0x0F) {
494 case RR:
495 pr_cont("RR(%d)", (control & 0xE0) >> 5);
496 break;
497 case RNR:
498 pr_cont("RNR(%d)", (control & 0xE0) >> 5);
499 break;
500 case REJ:
501 pr_cont("REJ(%d)", (control & 0xE0) >> 5);
502 break;
503 default:
504 pr_cont("[%02X]", control);
505 }
506 }
507
508 if (control & PF)
509 pr_cont("(P)");
510 else
511 pr_cont("(F)");
512
513 if (dlen) {
514 int ct = 0;
515 while (dlen--) {
516 if (ct % 8 == 0) {
517 pr_cont("\n");
518 pr_debug(" ");
519 }
520 pr_cont("%02X ", *data++);
521 ct++;
522 }
523 }
524 pr_cont("\n");
525}
526
527
528/*
529 * Link level transmission side
530 */
531
532/**
533 * gsm_stuff_packet - bytestuff a packet
534 * @ibuf: input
535 * @obuf: output
536 * @len: length of input
537 *
538 * Expand a buffer by bytestuffing it. The worst case size change
539 * is doubling and the caller is responsible for handing out
540 * suitable sized buffers.
541 */
542
543static int gsm_stuff_frame(const u8 *input, u8 *output, int len)
544{
545 int olen = 0;
546 while (len--) {
547 if (*input == GSM1_SOF || *input == GSM1_ESCAPE
548 || *input == XON || *input == XOFF) {
549 *output++ = GSM1_ESCAPE;
550 *output++ = *input++ ^ GSM1_ESCAPE_BITS;
551 olen++;
552 } else
553 *output++ = *input++;
554 olen++;
555 }
556 return olen;
557}
558
559/**
560 * gsm_send - send a control frame
561 * @gsm: our GSM mux
562 * @addr: address for control frame
563 * @cr: command/response bit
564 * @control: control byte including PF bit
565 *
566 * Format up and transmit a control frame. These do not go via the
567 * queueing logic as they should be transmitted ahead of data when
568 * they are needed.
569 *
570 * FIXME: Lock versus data TX path
571 */
572
573static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control)
574{
575 int len;
576 u8 cbuf[10];
577 u8 ibuf[3];
578
579 switch (gsm->encoding) {
580 case 0:
581 cbuf[0] = GSM0_SOF;
582 cbuf[1] = (addr << 2) | (cr << 1) | EA;
583 cbuf[2] = control;
584 cbuf[3] = EA; /* Length of data = 0 */
585 cbuf[4] = 0xFF - gsm_fcs_add_block(INIT_FCS, cbuf + 1, 3);
586 cbuf[5] = GSM0_SOF;
587 len = 6;
588 break;
589 case 1:
590 case 2:
591 /* Control frame + packing (but not frame stuffing) in mode 1 */
592 ibuf[0] = (addr << 2) | (cr << 1) | EA;
593 ibuf[1] = control;
594 ibuf[2] = 0xFF - gsm_fcs_add_block(INIT_FCS, ibuf, 2);
595 /* Stuffing may double the size worst case */
596 len = gsm_stuff_frame(ibuf, cbuf + 1, 3);
597 /* Now add the SOF markers */
598 cbuf[0] = GSM1_SOF;
599 cbuf[len + 1] = GSM1_SOF;
600 /* FIXME: we can omit the lead one in many cases */
601 len += 2;
602 break;
603 default:
604 WARN_ON(1);
605 return;
606 }
607 gsm->output(gsm, cbuf, len);
608 gsm_print_packet("-->", addr, cr, control, NULL, 0);
609}
610
611/**
612 * gsm_response - send a control response
613 * @gsm: our GSM mux
614 * @addr: address for control frame
615 * @control: control byte including PF bit
616 *
617 * Format up and transmit a link level response frame.
618 */
619
620static inline void gsm_response(struct gsm_mux *gsm, int addr, int control)
621{
622 gsm_send(gsm, addr, 0, control);
623}
624
625/**
626 * gsm_command - send a control command
627 * @gsm: our GSM mux
628 * @addr: address for control frame
629 * @control: control byte including PF bit
630 *
631 * Format up and transmit a link level command frame.
632 */
633
634static inline void gsm_command(struct gsm_mux *gsm, int addr, int control)
635{
636 gsm_send(gsm, addr, 1, control);
637}
638
639/* Data transmission */
640
641#define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */
642
643/**
644 * gsm_data_alloc - allocate data frame
645 * @gsm: GSM mux
646 * @addr: DLCI address
647 * @len: length excluding header and FCS
648 * @ctrl: control byte
649 *
650 * Allocate a new data buffer for sending frames with data. Space is left
651 * at the front for header bytes but that is treated as an implementation
652 * detail and not for the high level code to use
653 */
654
655static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
656 u8 ctrl)
657{
658 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN,
659 GFP_ATOMIC);
660 if (m == NULL)
661 return NULL;
662 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */
663 m->len = len;
664 m->addr = addr;
665 m->ctrl = ctrl;
666 m->next = NULL;
667 return m;
668}
669
670/**
671 * gsm_data_kick - poke the queue
672 * @gsm: GSM Mux
673 *
674 * The tty device has called us to indicate that room has appeared in
675 * the transmit queue. Ram more data into the pipe if we have any
676 *
677 * FIXME: lock against link layer control transmissions
678 */
679
680static void gsm_data_kick(struct gsm_mux *gsm)
681{
682 struct gsm_msg *msg = gsm->tx_head;
683 int len;
684 int skip_sof = 0;
685
686 /* FIXME: We need to apply this solely to data messages */
687 if (gsm->constipated)
688 return;
689
690 while (gsm->tx_head != NULL) {
691 msg = gsm->tx_head;
692 if (gsm->encoding != 0) {
693 gsm->txframe[0] = GSM1_SOF;
694 len = gsm_stuff_frame(msg->data,
695 gsm->txframe + 1, msg->len);
696 gsm->txframe[len + 1] = GSM1_SOF;
697 len += 2;
698 } else {
699 gsm->txframe[0] = GSM0_SOF;
700 memcpy(gsm->txframe + 1 , msg->data, msg->len);
701 gsm->txframe[msg->len + 1] = GSM0_SOF;
702 len = msg->len + 2;
703 }
704
705 if (debug & 4)
706 print_hex_dump_bytes("gsm_data_kick: ",
707 DUMP_PREFIX_OFFSET,
708 gsm->txframe, len);
709
710 if (gsm->output(gsm, gsm->txframe + skip_sof,
711 len - skip_sof) < 0)
712 break;
713 /* FIXME: Can eliminate one SOF in many more cases */
714 gsm->tx_head = msg->next;
715 if (gsm->tx_head == NULL)
716 gsm->tx_tail = NULL;
717 gsm->tx_bytes -= msg->len;
718 kfree(msg);
719 /* For a burst of frames skip the extra SOF within the
720 burst */
721 skip_sof = 1;
722 }
723}
724
725/**
726 * __gsm_data_queue - queue a UI or UIH frame
727 * @dlci: DLCI sending the data
728 * @msg: message queued
729 *
730 * Add data to the transmit queue and try and get stuff moving
731 * out of the mux tty if not already doing so. The Caller must hold
732 * the gsm tx lock.
733 */
734
735static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
736{
737 struct gsm_mux *gsm = dlci->gsm;
738 u8 *dp = msg->data;
739 u8 *fcs = dp + msg->len;
740
741 /* Fill in the header */
742 if (gsm->encoding == 0) {
743 if (msg->len < 128)
744 *--dp = (msg->len << 1) | EA;
745 else {
746 *--dp = (msg->len >> 7); /* bits 7 - 15 */
747 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */
748 }
749 }
750
751 *--dp = msg->ctrl;
752 if (gsm->initiator)
753 *--dp = (msg->addr << 2) | 2 | EA;
754 else
755 *--dp = (msg->addr << 2) | EA;
756 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp);
757 /* Ugly protocol layering violation */
758 if (msg->ctrl == UI || msg->ctrl == (UI|PF))
759 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len);
760 *fcs = 0xFF - *fcs;
761
762 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl,
763 msg->data, msg->len);
764
765 /* Move the header back and adjust the length, also allow for the FCS
766 now tacked on the end */
767 msg->len += (msg->data - dp) + 1;
768 msg->data = dp;
769
770 /* Add to the actual output queue */
771 if (gsm->tx_tail)
772 gsm->tx_tail->next = msg;
773 else
774 gsm->tx_head = msg;
775 gsm->tx_tail = msg;
776 gsm->tx_bytes += msg->len;
777 gsm_data_kick(gsm);
778}
779
780/**
781 * gsm_data_queue - queue a UI or UIH frame
782 * @dlci: DLCI sending the data
783 * @msg: message queued
784 *
785 * Add data to the transmit queue and try and get stuff moving
786 * out of the mux tty if not already doing so. Take the
787 * the gsm tx lock and dlci lock.
788 */
789
790static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
791{
792 unsigned long flags;
793 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
794 __gsm_data_queue(dlci, msg);
795 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
796}
797
798/**
799 * gsm_dlci_data_output - try and push data out of a DLCI
800 * @gsm: mux
801 * @dlci: the DLCI to pull data from
802 *
803 * Pull data from a DLCI and send it into the transmit queue if there
804 * is data. Keep to the MRU of the mux. This path handles the usual tty
805 * interface which is a byte stream with optional modem data.
806 *
807 * Caller must hold the tx_lock of the mux.
808 */
809
810static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci)
811{
812 struct gsm_msg *msg;
813 u8 *dp;
814 int len, total_size, size;
815 int h = dlci->adaption - 1;
816
817 total_size = 0;
818 while(1) {
819 len = kfifo_len(dlci->fifo);
820 if (len == 0)
821 return total_size;
822
823 /* MTU/MRU count only the data bits */
824 if (len > gsm->mtu)
825 len = gsm->mtu;
826
827 size = len + h;
828
829 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
830 /* FIXME: need a timer or something to kick this so it can't
831 get stuck with no work outstanding and no buffer free */
832 if (msg == NULL)
833 return -ENOMEM;
834 dp = msg->data;
835 switch (dlci->adaption) {
836 case 1: /* Unstructured */
837 break;
838 case 2: /* Unstructed with modem bits. Always one byte as we never
839 send inline break data */
840 *dp++ = gsm_encode_modem(dlci);
841 break;
842 }
843 WARN_ON(kfifo_out_locked(dlci->fifo, dp , len, &dlci->lock) != len);
844 __gsm_data_queue(dlci, msg);
845 total_size += size;
846 }
847 /* Bytes of data we used up */
848 return total_size;
849}
850
851/**
852 * gsm_dlci_data_output_framed - try and push data out of a DLCI
853 * @gsm: mux
854 * @dlci: the DLCI to pull data from
855 *
856 * Pull data from a DLCI and send it into the transmit queue if there
857 * is data. Keep to the MRU of the mux. This path handles framed data
858 * queued as skbuffs to the DLCI.
859 *
860 * Caller must hold the tx_lock of the mux.
861 */
862
863static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
864 struct gsm_dlci *dlci)
865{
866 struct gsm_msg *msg;
867 u8 *dp;
868 int len, size;
869 int last = 0, first = 0;
870 int overhead = 0;
871
872 /* One byte per frame is used for B/F flags */
873 if (dlci->adaption == 4)
874 overhead = 1;
875
876 /* dlci->skb is locked by tx_lock */
877 if (dlci->skb == NULL) {
878 dlci->skb = skb_dequeue_tail(&dlci->skb_list);
879 if (dlci->skb == NULL)
880 return 0;
881 first = 1;
882 }
883 len = dlci->skb->len + overhead;
884
885 /* MTU/MRU count only the data bits */
886 if (len > gsm->mtu) {
887 if (dlci->adaption == 3) {
888 /* Over long frame, bin it */
889 kfree_skb(dlci->skb);
890 dlci->skb = NULL;
891 return 0;
892 }
893 len = gsm->mtu;
894 } else
895 last = 1;
896
897 size = len + overhead;
898 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
899
900 /* FIXME: need a timer or something to kick this so it can't
901 get stuck with no work outstanding and no buffer free */
902 if (msg == NULL) {
903 skb_queue_tail(&dlci->skb_list, dlci->skb);
904 dlci->skb = NULL;
905 return -ENOMEM;
906 }
907 dp = msg->data;
908
909 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */
910 /* Flag byte to carry the start/end info */
911 *dp++ = last << 7 | first << 6 | 1; /* EA */
912 len--;
913 }
914 memcpy(dp, dlci->skb->data, len);
915 skb_pull(dlci->skb, len);
916 __gsm_data_queue(dlci, msg);
917 if (last) {
918 kfree_skb(dlci->skb);
919 dlci->skb = NULL;
920 }
921 return size;
922}
923
924/**
925 * gsm_dlci_data_sweep - look for data to send
926 * @gsm: the GSM mux
927 *
928 * Sweep the GSM mux channels in priority order looking for ones with
929 * data to send. We could do with optimising this scan a bit. We aim
930 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit
931 * TX_THRESH_LO we get called again
932 *
933 * FIXME: We should round robin between groups and in theory you can
934 * renegotiate DLCI priorities with optional stuff. Needs optimising.
935 */
936
937static void gsm_dlci_data_sweep(struct gsm_mux *gsm)
938{
939 int len;
940 /* Priority ordering: We should do priority with RR of the groups */
941 int i = 1;
942
943 while (i < NUM_DLCI) {
944 struct gsm_dlci *dlci;
945
946 if (gsm->tx_bytes > TX_THRESH_HI)
947 break;
948 dlci = gsm->dlci[i];
949 if (dlci == NULL || dlci->constipated) {
950 i++;
951 continue;
952 }
953 if (dlci->adaption < 3 && !dlci->net)
954 len = gsm_dlci_data_output(gsm, dlci);
955 else
956 len = gsm_dlci_data_output_framed(gsm, dlci);
957 if (len < 0)
958 break;
959 /* DLCI empty - try the next */
960 if (len == 0)
961 i++;
962 }
963}
964
965/**
966 * gsm_dlci_data_kick - transmit if possible
967 * @dlci: DLCI to kick
968 *
969 * Transmit data from this DLCI if the queue is empty. We can't rely on
970 * a tty wakeup except when we filled the pipe so we need to fire off
971 * new data ourselves in other cases.
972 */
973
974static void gsm_dlci_data_kick(struct gsm_dlci *dlci)
975{
976 unsigned long flags;
977 int sweep;
978
979 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
980 /* If we have nothing running then we need to fire up */
981 sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO);
982 if (dlci->gsm->tx_bytes == 0) {
983 if (dlci->net)
984 gsm_dlci_data_output_framed(dlci->gsm, dlci);
985 else
986 gsm_dlci_data_output(dlci->gsm, dlci);
987 }
988 if (sweep)
989 gsm_dlci_data_sweep(dlci->gsm);
990 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
991}
992
993/*
994 * Control message processing
995 */
996
997
998/**
999 * gsm_control_reply - send a response frame to a control
1000 * @gsm: gsm channel
1001 * @cmd: the command to use
1002 * @data: data to follow encoded info
1003 * @dlen: length of data
1004 *
1005 * Encode up and queue a UI/UIH frame containing our response.
1006 */
1007
1008static void gsm_control_reply(struct gsm_mux *gsm, int cmd, u8 *data,
1009 int dlen)
1010{
1011 struct gsm_msg *msg;
1012 msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype);
1013 if (msg == NULL)
1014 return;
1015 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */
1016 msg->data[1] = (dlen << 1) | EA;
1017 memcpy(msg->data + 2, data, dlen);
1018 gsm_data_queue(gsm->dlci[0], msg);
1019}
1020
1021/**
1022 * gsm_process_modem - process received modem status
1023 * @tty: virtual tty bound to the DLCI
1024 * @dlci: DLCI to affect
1025 * @modem: modem bits (full EA)
1026 *
1027 * Used when a modem control message or line state inline in adaption
1028 * layer 2 is processed. Sort out the local modem state and throttles
1029 */
1030
1031static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
1032 u32 modem, int clen)
1033{
1034 int mlines = 0;
1035 u8 brk = 0;
1036
1037 /* The modem status command can either contain one octet (v.24 signals)
1038 or two octets (v.24 signals + break signals). The length field will
1039 either be 2 or 3 respectively. This is specified in section
1040 5.4.6.3.7 of the 27.010 mux spec. */
1041
1042 if (clen == 2)
1043 modem = modem & 0x7f;
1044 else {
1045 brk = modem & 0x7f;
1046 modem = (modem >> 7) & 0x7f;
1047 };
1048
1049 /* Flow control/ready to communicate */
1050 if (modem & MDM_FC) {
1051 /* Need to throttle our output on this device */
1052 dlci->constipated = 1;
1053 }
1054 if (modem & MDM_RTC) {
1055 mlines |= TIOCM_DSR | TIOCM_DTR;
1056 dlci->constipated = 0;
1057 gsm_dlci_data_kick(dlci);
1058 }
1059 /* Map modem bits */
1060 if (modem & MDM_RTR)
1061 mlines |= TIOCM_RTS | TIOCM_CTS;
1062 if (modem & MDM_IC)
1063 mlines |= TIOCM_RI;
1064 if (modem & MDM_DV)
1065 mlines |= TIOCM_CD;
1066
1067 /* Carrier drop -> hangup */
1068 if (tty) {
1069 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD))
1070 if (!(tty->termios->c_cflag & CLOCAL))
1071 tty_hangup(tty);
1072 if (brk & 0x01)
1073 tty_insert_flip_char(tty, 0, TTY_BREAK);
1074 }
1075 dlci->modem_rx = mlines;
1076}
1077
1078/**
1079 * gsm_control_modem - modem status received
1080 * @gsm: GSM channel
1081 * @data: data following command
1082 * @clen: command length
1083 *
1084 * We have received a modem status control message. This is used by
1085 * the GSM mux protocol to pass virtual modem line status and optionally
1086 * to indicate break signals. Unpack it, convert to Linux representation
1087 * and if need be stuff a break message down the tty.
1088 */
1089
1090static void gsm_control_modem(struct gsm_mux *gsm, u8 *data, int clen)
1091{
1092 unsigned int addr = 0;
1093 unsigned int modem = 0;
1094 struct gsm_dlci *dlci;
1095 int len = clen;
1096 u8 *dp = data;
1097 struct tty_struct *tty;
1098
1099 while (gsm_read_ea(&addr, *dp++) == 0) {
1100 len--;
1101 if (len == 0)
1102 return;
1103 }
1104 /* Must be at least one byte following the EA */
1105 len--;
1106 if (len <= 0)
1107 return;
1108
1109 addr >>= 1;
1110 /* Closed port, or invalid ? */
1111 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1112 return;
1113 dlci = gsm->dlci[addr];
1114
1115 while (gsm_read_ea(&modem, *dp++) == 0) {
1116 len--;
1117 if (len == 0)
1118 return;
1119 }
1120 tty = tty_port_tty_get(&dlci->port);
1121 gsm_process_modem(tty, dlci, modem, clen);
1122 if (tty) {
1123 tty_wakeup(tty);
1124 tty_kref_put(tty);
1125 }
1126 gsm_control_reply(gsm, CMD_MSC, data, clen);
1127}
1128
1129/**
1130 * gsm_control_rls - remote line status
1131 * @gsm: GSM channel
1132 * @data: data bytes
1133 * @clen: data length
1134 *
1135 * The modem sends us a two byte message on the control channel whenever
1136 * it wishes to send us an error state from the virtual link. Stuff
1137 * this into the uplink tty if present
1138 */
1139
1140static void gsm_control_rls(struct gsm_mux *gsm, u8 *data, int clen)
1141{
1142 struct tty_struct *tty;
1143 unsigned int addr = 0 ;
1144 u8 bits;
1145 int len = clen;
1146 u8 *dp = data;
1147
1148 while (gsm_read_ea(&addr, *dp++) == 0) {
1149 len--;
1150 if (len == 0)
1151 return;
1152 }
1153 /* Must be at least one byte following ea */
1154 len--;
1155 if (len <= 0)
1156 return;
1157 addr >>= 1;
1158 /* Closed port, or invalid ? */
1159 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1160 return;
1161 /* No error ? */
1162 bits = *dp;
1163 if ((bits & 1) == 0)
1164 return;
1165 /* See if we have an uplink tty */
1166 tty = tty_port_tty_get(&gsm->dlci[addr]->port);
1167
1168 if (tty) {
1169 if (bits & 2)
1170 tty_insert_flip_char(tty, 0, TTY_OVERRUN);
1171 if (bits & 4)
1172 tty_insert_flip_char(tty, 0, TTY_PARITY);
1173 if (bits & 8)
1174 tty_insert_flip_char(tty, 0, TTY_FRAME);
1175 tty_flip_buffer_push(tty);
1176 tty_kref_put(tty);
1177 }
1178 gsm_control_reply(gsm, CMD_RLS, data, clen);
1179}
1180
1181static void gsm_dlci_begin_close(struct gsm_dlci *dlci);
1182
1183/**
1184 * gsm_control_message - DLCI 0 control processing
1185 * @gsm: our GSM mux
1186 * @command: the command EA
1187 * @data: data beyond the command/length EAs
1188 * @clen: length
1189 *
1190 * Input processor for control messages from the other end of the link.
1191 * Processes the incoming request and queues a response frame or an
1192 * NSC response if not supported
1193 */
1194
1195static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
1196 u8 *data, int clen)
1197{
1198 u8 buf[1];
1199 unsigned long flags;
1200
1201 switch (command) {
1202 case CMD_CLD: {
1203 struct gsm_dlci *dlci = gsm->dlci[0];
1204 /* Modem wishes to close down */
1205 if (dlci) {
1206 dlci->dead = 1;
1207 gsm->dead = 1;
1208 gsm_dlci_begin_close(dlci);
1209 }
1210 }
1211 break;
1212 case CMD_TEST:
1213 /* Modem wishes to test, reply with the data */
1214 gsm_control_reply(gsm, CMD_TEST, data, clen);
1215 break;
1216 case CMD_FCON:
1217 /* Modem wants us to STFU */
1218 gsm->constipated = 1;
1219 gsm_control_reply(gsm, CMD_FCON, NULL, 0);
1220 break;
1221 case CMD_FCOFF:
1222 /* Modem can accept data again */
1223 gsm->constipated = 0;
1224 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0);
1225 /* Kick the link in case it is idling */
1226 spin_lock_irqsave(&gsm->tx_lock, flags);
1227 gsm_data_kick(gsm);
1228 spin_unlock_irqrestore(&gsm->tx_lock, flags);
1229 break;
1230 case CMD_MSC:
1231 /* Out of band modem line change indicator for a DLCI */
1232 gsm_control_modem(gsm, data, clen);
1233 break;
1234 case CMD_RLS:
1235 /* Out of band error reception for a DLCI */
1236 gsm_control_rls(gsm, data, clen);
1237 break;
1238 case CMD_PSC:
1239 /* Modem wishes to enter power saving state */
1240 gsm_control_reply(gsm, CMD_PSC, NULL, 0);
1241 break;
1242 /* Optional unsupported commands */
1243 case CMD_PN: /* Parameter negotiation */
1244 case CMD_RPN: /* Remote port negotiation */
1245 case CMD_SNC: /* Service negotiation command */
1246 default:
1247 /* Reply to bad commands with an NSC */
1248 buf[0] = command;
1249 gsm_control_reply(gsm, CMD_NSC, buf, 1);
1250 break;
1251 }
1252}
1253
1254/**
1255 * gsm_control_response - process a response to our control
1256 * @gsm: our GSM mux
1257 * @command: the command (response) EA
1258 * @data: data beyond the command/length EA
1259 * @clen: length
1260 *
1261 * Process a response to an outstanding command. We only allow a single
1262 * control message in flight so this is fairly easy. All the clean up
1263 * is done by the caller, we just update the fields, flag it as done
1264 * and return
1265 */
1266
1267static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
1268 u8 *data, int clen)
1269{
1270 struct gsm_control *ctrl;
1271 unsigned long flags;
1272
1273 spin_lock_irqsave(&gsm->control_lock, flags);
1274
1275 ctrl = gsm->pending_cmd;
1276 /* Does the reply match our command */
1277 command |= 1;
1278 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) {
1279 /* Our command was replied to, kill the retry timer */
1280 del_timer(&gsm->t2_timer);
1281 gsm->pending_cmd = NULL;
1282 /* Rejected by the other end */
1283 if (command == CMD_NSC)
1284 ctrl->error = -EOPNOTSUPP;
1285 ctrl->done = 1;
1286 wake_up(&gsm->event);
1287 }
1288 spin_unlock_irqrestore(&gsm->control_lock, flags);
1289}
1290
1291/**
1292 * gsm_control_transmit - send control packet
1293 * @gsm: gsm mux
1294 * @ctrl: frame to send
1295 *
1296 * Send out a pending control command (called under control lock)
1297 */
1298
1299static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl)
1300{
1301 struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, gsm->ftype);
1302 if (msg == NULL)
1303 return;
1304 msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */
1305 memcpy(msg->data + 1, ctrl->data, ctrl->len);
1306 gsm_data_queue(gsm->dlci[0], msg);
1307}
1308
1309/**
1310 * gsm_control_retransmit - retransmit a control frame
1311 * @data: pointer to our gsm object
1312 *
1313 * Called off the T2 timer expiry in order to retransmit control frames
1314 * that have been lost in the system somewhere. The control_lock protects
1315 * us from colliding with another sender or a receive completion event.
1316 * In that situation the timer may still occur in a small window but
1317 * gsm->pending_cmd will be NULL and we just let the timer expire.
1318 */
1319
1320static void gsm_control_retransmit(unsigned long data)
1321{
1322 struct gsm_mux *gsm = (struct gsm_mux *)data;
1323 struct gsm_control *ctrl;
1324 unsigned long flags;
1325 spin_lock_irqsave(&gsm->control_lock, flags);
1326 ctrl = gsm->pending_cmd;
1327 if (ctrl) {
1328 gsm->cretries--;
1329 if (gsm->cretries == 0) {
1330 gsm->pending_cmd = NULL;
1331 ctrl->error = -ETIMEDOUT;
1332 ctrl->done = 1;
1333 spin_unlock_irqrestore(&gsm->control_lock, flags);
1334 wake_up(&gsm->event);
1335 return;
1336 }
1337 gsm_control_transmit(gsm, ctrl);
1338 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1339 }
1340 spin_unlock_irqrestore(&gsm->control_lock, flags);
1341}
1342
1343/**
1344 * gsm_control_send - send a control frame on DLCI 0
1345 * @gsm: the GSM channel
1346 * @command: command to send including CR bit
1347 * @data: bytes of data (must be kmalloced)
1348 * @len: length of the block to send
1349 *
1350 * Queue and dispatch a control command. Only one command can be
1351 * active at a time. In theory more can be outstanding but the matching
1352 * gets really complicated so for now stick to one outstanding.
1353 */
1354
1355static struct gsm_control *gsm_control_send(struct gsm_mux *gsm,
1356 unsigned int command, u8 *data, int clen)
1357{
1358 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control),
1359 GFP_KERNEL);
1360 unsigned long flags;
1361 if (ctrl == NULL)
1362 return NULL;
1363retry:
1364 wait_event(gsm->event, gsm->pending_cmd == NULL);
1365 spin_lock_irqsave(&gsm->control_lock, flags);
1366 if (gsm->pending_cmd != NULL) {
1367 spin_unlock_irqrestore(&gsm->control_lock, flags);
1368 goto retry;
1369 }
1370 ctrl->cmd = command;
1371 ctrl->data = data;
1372 ctrl->len = clen;
1373 gsm->pending_cmd = ctrl;
1374 gsm->cretries = gsm->n2;
1375 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1376 gsm_control_transmit(gsm, ctrl);
1377 spin_unlock_irqrestore(&gsm->control_lock, flags);
1378 return ctrl;
1379}
1380
1381/**
1382 * gsm_control_wait - wait for a control to finish
1383 * @gsm: GSM mux
1384 * @control: control we are waiting on
1385 *
1386 * Waits for the control to complete or time out. Frees any used
1387 * resources and returns 0 for success, or an error if the remote
1388 * rejected or ignored the request.
1389 */
1390
1391static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
1392{
1393 int err;
1394 wait_event(gsm->event, control->done == 1);
1395 err = control->error;
1396 kfree(control);
1397 return err;
1398}
1399
1400
1401/*
1402 * DLCI level handling: Needs krefs
1403 */
1404
1405/*
1406 * State transitions and timers
1407 */
1408
1409/**
1410 * gsm_dlci_close - a DLCI has closed
1411 * @dlci: DLCI that closed
1412 *
1413 * Perform processing when moving a DLCI into closed state. If there
1414 * is an attached tty this is hung up
1415 */
1416
1417static void gsm_dlci_close(struct gsm_dlci *dlci)
1418{
1419 del_timer(&dlci->t1);
1420 if (debug & 8)
1421 pr_debug("DLCI %d goes closed.\n", dlci->addr);
1422 dlci->state = DLCI_CLOSED;
1423 if (dlci->addr != 0) {
1424 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1425 if (tty) {
1426 tty_hangup(tty);
1427 tty_kref_put(tty);
1428 }
1429 kfifo_reset(dlci->fifo);
1430 } else
1431 dlci->gsm->dead = 1;
1432 wake_up(&dlci->gsm->event);
1433 /* A DLCI 0 close is a MUX termination so we need to kick that
1434 back to userspace somehow */
1435}
1436
1437/**
1438 * gsm_dlci_open - a DLCI has opened
1439 * @dlci: DLCI that opened
1440 *
1441 * Perform processing when moving a DLCI into open state.
1442 */
1443
1444static void gsm_dlci_open(struct gsm_dlci *dlci)
1445{
1446 /* Note that SABM UA .. SABM UA first UA lost can mean that we go
1447 open -> open */
1448 del_timer(&dlci->t1);
1449 /* This will let a tty open continue */
1450 dlci->state = DLCI_OPEN;
1451 if (debug & 8)
1452 pr_debug("DLCI %d goes open.\n", dlci->addr);
1453 wake_up(&dlci->gsm->event);
1454}
1455
1456/**
1457 * gsm_dlci_t1 - T1 timer expiry
1458 * @dlci: DLCI that opened
1459 *
1460 * The T1 timer handles retransmits of control frames (essentially of
1461 * SABM and DISC). We resend the command until the retry count runs out
1462 * in which case an opening port goes back to closed and a closing port
1463 * is simply put into closed state (any further frames from the other
1464 * end will get a DM response)
1465 */
1466
1467static void gsm_dlci_t1(unsigned long data)
1468{
1469 struct gsm_dlci *dlci = (struct gsm_dlci *)data;
1470 struct gsm_mux *gsm = dlci->gsm;
1471
1472 switch (dlci->state) {
1473 case DLCI_OPENING:
1474 dlci->retries--;
1475 if (dlci->retries) {
1476 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1477 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1478 } else
1479 gsm_dlci_close(dlci);
1480 break;
1481 case DLCI_CLOSING:
1482 dlci->retries--;
1483 if (dlci->retries) {
1484 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1485 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1486 } else
1487 gsm_dlci_close(dlci);
1488 break;
1489 }
1490}
1491
1492/**
1493 * gsm_dlci_begin_open - start channel open procedure
1494 * @dlci: DLCI to open
1495 *
1496 * Commence opening a DLCI from the Linux side. We issue SABM messages
1497 * to the modem which should then reply with a UA, at which point we
1498 * will move into open state. Opening is done asynchronously with retry
1499 * running off timers and the responses.
1500 */
1501
1502static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
1503{
1504 struct gsm_mux *gsm = dlci->gsm;
1505 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING)
1506 return;
1507 dlci->retries = gsm->n2;
1508 dlci->state = DLCI_OPENING;
1509 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1510 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1511}
1512
1513/**
1514 * gsm_dlci_begin_close - start channel open procedure
1515 * @dlci: DLCI to open
1516 *
1517 * Commence closing a DLCI from the Linux side. We issue DISC messages
1518 * to the modem which should then reply with a UA, at which point we
1519 * will move into closed state. Closing is done asynchronously with retry
1520 * off timers. We may also receive a DM reply from the other end which
1521 * indicates the channel was already closed.
1522 */
1523
1524static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
1525{
1526 struct gsm_mux *gsm = dlci->gsm;
1527 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
1528 return;
1529 dlci->retries = gsm->n2;
1530 dlci->state = DLCI_CLOSING;
1531 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1532 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1533}
1534
1535/**
1536 * gsm_dlci_data - data arrived
1537 * @dlci: channel
1538 * @data: block of bytes received
1539 * @len: length of received block
1540 *
1541 * A UI or UIH frame has arrived which contains data for a channel
1542 * other than the control channel. If the relevant virtual tty is
1543 * open we shovel the bits down it, if not we drop them.
1544 */
1545
1546static void gsm_dlci_data(struct gsm_dlci *dlci, u8 *data, int clen)
1547{
1548 /* krefs .. */
1549 struct tty_port *port = &dlci->port;
1550 struct tty_struct *tty = tty_port_tty_get(port);
1551 unsigned int modem = 0;
1552 int len = clen;
1553
1554 if (debug & 16)
1555 pr_debug("%d bytes for tty %p\n", len, tty);
1556 if (tty) {
1557 switch (dlci->adaption) {
1558 /* Unsupported types */
1559 /* Packetised interruptible data */
1560 case 4:
1561 break;
1562 /* Packetised uininterruptible voice/data */
1563 case 3:
1564 break;
1565 /* Asynchronous serial with line state in each frame */
1566 case 2:
1567 while (gsm_read_ea(&modem, *data++) == 0) {
1568 len--;
1569 if (len == 0)
1570 return;
1571 }
1572 gsm_process_modem(tty, dlci, modem, clen);
1573 /* Line state will go via DLCI 0 controls only */
1574 case 1:
1575 default:
1576 tty_insert_flip_string(tty, data, len);
1577 tty_flip_buffer_push(tty);
1578 }
1579 tty_kref_put(tty);
1580 }
1581}
1582
1583/**
1584 * gsm_dlci_control - data arrived on control channel
1585 * @dlci: channel
1586 * @data: block of bytes received
1587 * @len: length of received block
1588 *
1589 * A UI or UIH frame has arrived which contains data for DLCI 0 the
1590 * control channel. This should contain a command EA followed by
1591 * control data bytes. The command EA contains a command/response bit
1592 * and we divide up the work accordingly.
1593 */
1594
1595static void gsm_dlci_command(struct gsm_dlci *dlci, u8 *data, int len)
1596{
1597 /* See what command is involved */
1598 unsigned int command = 0;
1599 while (len-- > 0) {
1600 if (gsm_read_ea(&command, *data++) == 1) {
1601 int clen = *data++;
1602 len--;
1603 /* FIXME: this is properly an EA */
1604 clen >>= 1;
1605 /* Malformed command ? */
1606 if (clen > len)
1607 return;
1608 if (command & 1)
1609 gsm_control_message(dlci->gsm, command,
1610 data, clen);
1611 else
1612 gsm_control_response(dlci->gsm, command,
1613 data, clen);
1614 return;
1615 }
1616 }
1617}
1618
1619/*
1620 * Allocate/Free DLCI channels
1621 */
1622
1623/**
1624 * gsm_dlci_alloc - allocate a DLCI
1625 * @gsm: GSM mux
1626 * @addr: address of the DLCI
1627 *
1628 * Allocate and install a new DLCI object into the GSM mux.
1629 *
1630 * FIXME: review locking races
1631 */
1632
1633static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
1634{
1635 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC);
1636 if (dlci == NULL)
1637 return NULL;
1638 spin_lock_init(&dlci->lock);
1639 kref_init(&dlci->ref);
1640 mutex_init(&dlci->mutex);
1641 dlci->fifo = &dlci->_fifo;
1642 if (kfifo_alloc(&dlci->_fifo, 4096, GFP_KERNEL) < 0) {
1643 kfree(dlci);
1644 return NULL;
1645 }
1646
1647 skb_queue_head_init(&dlci->skb_list);
1648 init_timer(&dlci->t1);
1649 dlci->t1.function = gsm_dlci_t1;
1650 dlci->t1.data = (unsigned long)dlci;
1651 tty_port_init(&dlci->port);
1652 dlci->port.ops = &gsm_port_ops;
1653 dlci->gsm = gsm;
1654 dlci->addr = addr;
1655 dlci->adaption = gsm->adaption;
1656 dlci->state = DLCI_CLOSED;
1657 if (addr)
1658 dlci->data = gsm_dlci_data;
1659 else
1660 dlci->data = gsm_dlci_command;
1661 gsm->dlci[addr] = dlci;
1662 return dlci;
1663}
1664
1665/**
1666 * gsm_dlci_free - free DLCI
1667 * @dlci: DLCI to free
1668 *
1669 * Free up a DLCI.
1670 *
1671 * Can sleep.
1672 */
1673static void gsm_dlci_free(struct kref *ref)
1674{
1675 struct gsm_dlci *dlci = container_of(ref, struct gsm_dlci, ref);
1676
1677 del_timer_sync(&dlci->t1);
1678 dlci->gsm->dlci[dlci->addr] = NULL;
1679 kfifo_free(dlci->fifo);
1680 while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
1681 kfree_skb(dlci->skb);
1682 kfree(dlci);
1683}
1684
1685static inline void dlci_get(struct gsm_dlci *dlci)
1686{
1687 kref_get(&dlci->ref);
1688}
1689
1690static inline void dlci_put(struct gsm_dlci *dlci)
1691{
1692 kref_put(&dlci->ref, gsm_dlci_free);
1693}
1694
1695/**
1696 * gsm_dlci_release - release DLCI
1697 * @dlci: DLCI to destroy
1698 *
1699 * Release a DLCI. Actual free is deferred until either
1700 * mux is closed or tty is closed - whichever is last.
1701 *
1702 * Can sleep.
1703 */
1704static void gsm_dlci_release(struct gsm_dlci *dlci)
1705{
1706 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1707 if (tty) {
1708 tty_vhangup(tty);
1709 tty_kref_put(tty);
1710 }
1711 dlci_put(dlci);
1712}
1713
1714/*
1715 * LAPBish link layer logic
1716 */
1717
1718/**
1719 * gsm_queue - a GSM frame is ready to process
1720 * @gsm: pointer to our gsm mux
1721 *
1722 * At this point in time a frame has arrived and been demangled from
1723 * the line encoding. All the differences between the encodings have
1724 * been handled below us and the frame is unpacked into the structures.
1725 * The fcs holds the header FCS but any data FCS must be added here.
1726 */
1727
1728static void gsm_queue(struct gsm_mux *gsm)
1729{
1730 struct gsm_dlci *dlci;
1731 u8 cr;
1732 int address;
1733 /* We have to sneak a look at the packet body to do the FCS.
1734 A somewhat layering violation in the spec */
1735
1736 if ((gsm->control & ~PF) == UI)
1737 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len);
1738 if (gsm->encoding == 0){
1739 /* WARNING: gsm->received_fcs is used for gsm->encoding = 0 only.
1740 In this case it contain the last piece of data
1741 required to generate final CRC */
1742 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs);
1743 }
1744 if (gsm->fcs != GOOD_FCS) {
1745 gsm->bad_fcs++;
1746 if (debug & 4)
1747 pr_debug("BAD FCS %02x\n", gsm->fcs);
1748 return;
1749 }
1750 address = gsm->address >> 1;
1751 if (address >= NUM_DLCI)
1752 goto invalid;
1753
1754 cr = gsm->address & 1; /* C/R bit */
1755
1756 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
1757
1758 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */
1759 dlci = gsm->dlci[address];
1760
1761 switch (gsm->control) {
1762 case SABM|PF:
1763 if (cr == 0)
1764 goto invalid;
1765 if (dlci == NULL)
1766 dlci = gsm_dlci_alloc(gsm, address);
1767 if (dlci == NULL)
1768 return;
1769 if (dlci->dead)
1770 gsm_response(gsm, address, DM);
1771 else {
1772 gsm_response(gsm, address, UA);
1773 gsm_dlci_open(dlci);
1774 }
1775 break;
1776 case DISC|PF:
1777 if (cr == 0)
1778 goto invalid;
1779 if (dlci == NULL || dlci->state == DLCI_CLOSED) {
1780 gsm_response(gsm, address, DM);
1781 return;
1782 }
1783 /* Real close complete */
1784 gsm_response(gsm, address, UA);
1785 gsm_dlci_close(dlci);
1786 break;
1787 case UA:
1788 case UA|PF:
1789 if (cr == 0 || dlci == NULL)
1790 break;
1791 switch (dlci->state) {
1792 case DLCI_CLOSING:
1793 gsm_dlci_close(dlci);
1794 break;
1795 case DLCI_OPENING:
1796 gsm_dlci_open(dlci);
1797 break;
1798 }
1799 break;
1800 case DM: /* DM can be valid unsolicited */
1801 case DM|PF:
1802 if (cr)
1803 goto invalid;
1804 if (dlci == NULL)
1805 return;
1806 gsm_dlci_close(dlci);
1807 break;
1808 case UI:
1809 case UI|PF:
1810 case UIH:
1811 case UIH|PF:
1812#if 0
1813 if (cr)
1814 goto invalid;
1815#endif
1816 if (dlci == NULL || dlci->state != DLCI_OPEN) {
1817 gsm_command(gsm, address, DM|PF);
1818 return;
1819 }
1820 dlci->data(dlci, gsm->buf, gsm->len);
1821 break;
1822 default:
1823 goto invalid;
1824 }
1825 return;
1826invalid:
1827 gsm->malformed++;
1828 return;
1829}
1830
1831
1832/**
1833 * gsm0_receive - perform processing for non-transparency
1834 * @gsm: gsm data for this ldisc instance
1835 * @c: character
1836 *
1837 * Receive bytes in gsm mode 0
1838 */
1839
1840static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
1841{
1842 unsigned int len;
1843
1844 switch (gsm->state) {
1845 case GSM_SEARCH: /* SOF marker */
1846 if (c == GSM0_SOF) {
1847 gsm->state = GSM_ADDRESS;
1848 gsm->address = 0;
1849 gsm->len = 0;
1850 gsm->fcs = INIT_FCS;
1851 }
1852 break;
1853 case GSM_ADDRESS: /* Address EA */
1854 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1855 if (gsm_read_ea(&gsm->address, c))
1856 gsm->state = GSM_CONTROL;
1857 break;
1858 case GSM_CONTROL: /* Control Byte */
1859 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1860 gsm->control = c;
1861 gsm->state = GSM_LEN0;
1862 break;
1863 case GSM_LEN0: /* Length EA */
1864 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1865 if (gsm_read_ea(&gsm->len, c)) {
1866 if (gsm->len > gsm->mru) {
1867 gsm->bad_size++;
1868 gsm->state = GSM_SEARCH;
1869 break;
1870 }
1871 gsm->count = 0;
1872 if (!gsm->len)
1873 gsm->state = GSM_FCS;
1874 else
1875 gsm->state = GSM_DATA;
1876 break;
1877 }
1878 gsm->state = GSM_LEN1;
1879 break;
1880 case GSM_LEN1:
1881 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1882 len = c;
1883 gsm->len |= len << 7;
1884 if (gsm->len > gsm->mru) {
1885 gsm->bad_size++;
1886 gsm->state = GSM_SEARCH;
1887 break;
1888 }
1889 gsm->count = 0;
1890 if (!gsm->len)
1891 gsm->state = GSM_FCS;
1892 else
1893 gsm->state = GSM_DATA;
1894 break;
1895 case GSM_DATA: /* Data */
1896 gsm->buf[gsm->count++] = c;
1897 if (gsm->count == gsm->len)
1898 gsm->state = GSM_FCS;
1899 break;
1900 case GSM_FCS: /* FCS follows the packet */
1901 gsm->received_fcs = c;
1902 gsm_queue(gsm);
1903 gsm->state = GSM_SSOF;
1904 break;
1905 case GSM_SSOF:
1906 if (c == GSM0_SOF) {
1907 gsm->state = GSM_SEARCH;
1908 break;
1909 }
1910 break;
1911 }
1912}
1913
1914/**
1915 * gsm1_receive - perform processing for non-transparency
1916 * @gsm: gsm data for this ldisc instance
1917 * @c: character
1918 *
1919 * Receive bytes in mode 1 (Advanced option)
1920 */
1921
1922static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
1923{
1924 if (c == GSM1_SOF) {
1925 /* EOF is only valid in frame if we have got to the data state
1926 and received at least one byte (the FCS) */
1927 if (gsm->state == GSM_DATA && gsm->count) {
1928 /* Extract the FCS */
1929 gsm->count--;
1930 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
1931 gsm->len = gsm->count;
1932 gsm_queue(gsm);
1933 gsm->state = GSM_START;
1934 return;
1935 }
1936 /* Any partial frame was a runt so go back to start */
1937 if (gsm->state != GSM_START) {
1938 gsm->malformed++;
1939 gsm->state = GSM_START;
1940 }
1941 /* A SOF in GSM_START means we are still reading idling or
1942 framing bytes */
1943 return;
1944 }
1945
1946 if (c == GSM1_ESCAPE) {
1947 gsm->escape = 1;
1948 return;
1949 }
1950
1951 /* Only an unescaped SOF gets us out of GSM search */
1952 if (gsm->state == GSM_SEARCH)
1953 return;
1954
1955 if (gsm->escape) {
1956 c ^= GSM1_ESCAPE_BITS;
1957 gsm->escape = 0;
1958 }
1959 switch (gsm->state) {
1960 case GSM_START: /* First byte after SOF */
1961 gsm->address = 0;
1962 gsm->state = GSM_ADDRESS;
1963 gsm->fcs = INIT_FCS;
1964 /* Drop through */
1965 case GSM_ADDRESS: /* Address continuation */
1966 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1967 if (gsm_read_ea(&gsm->address, c))
1968 gsm->state = GSM_CONTROL;
1969 break;
1970 case GSM_CONTROL: /* Control Byte */
1971 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1972 gsm->control = c;
1973 gsm->count = 0;
1974 gsm->state = GSM_DATA;
1975 break;
1976 case GSM_DATA: /* Data */
1977 if (gsm->count > gsm->mru) { /* Allow one for the FCS */
1978 gsm->state = GSM_OVERRUN;
1979 gsm->bad_size++;
1980 } else
1981 gsm->buf[gsm->count++] = c;
1982 break;
1983 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */
1984 break;
1985 }
1986}
1987
1988/**
1989 * gsm_error - handle tty error
1990 * @gsm: ldisc data
1991 * @data: byte received (may be invalid)
1992 * @flag: error received
1993 *
1994 * Handle an error in the receipt of data for a frame. Currently we just
1995 * go back to hunting for a SOF.
1996 *
1997 * FIXME: better diagnostics ?
1998 */
1999
2000static void gsm_error(struct gsm_mux *gsm,
2001 unsigned char data, unsigned char flag)
2002{
2003 gsm->state = GSM_SEARCH;
2004 gsm->io_error++;
2005}
2006
2007/**
2008 * gsm_cleanup_mux - generic GSM protocol cleanup
2009 * @gsm: our mux
2010 *
2011 * Clean up the bits of the mux which are the same for all framing
2012 * protocols. Remove the mux from the mux table, stop all the timers
2013 * and then shut down each device hanging up the channels as we go.
2014 */
2015
2016void gsm_cleanup_mux(struct gsm_mux *gsm)
2017{
2018 int i;
2019 struct gsm_dlci *dlci = gsm->dlci[0];
2020 struct gsm_msg *txq;
2021 struct gsm_control *gc;
2022
2023 gsm->dead = 1;
2024
2025 spin_lock(&gsm_mux_lock);
2026 for (i = 0; i < MAX_MUX; i++) {
2027 if (gsm_mux[i] == gsm) {
2028 gsm_mux[i] = NULL;
2029 break;
2030 }
2031 }
2032 spin_unlock(&gsm_mux_lock);
2033 WARN_ON(i == MAX_MUX);
2034
2035 /* In theory disconnecting DLCI 0 is sufficient but for some
2036 modems this is apparently not the case. */
2037 if (dlci) {
2038 gc = gsm_control_send(gsm, CMD_CLD, NULL, 0);
2039 if (gc)
2040 gsm_control_wait(gsm, gc);
2041 }
2042 del_timer_sync(&gsm->t2_timer);
2043 /* Now we are sure T2 has stopped */
2044 if (dlci) {
2045 dlci->dead = 1;
2046 gsm_dlci_begin_close(dlci);
2047 wait_event_interruptible(gsm->event,
2048 dlci->state == DLCI_CLOSED);
2049 }
2050 /* Free up any link layer users */
2051 for (i = 0; i < NUM_DLCI; i++)
2052 if (gsm->dlci[i])
2053 gsm_dlci_release(gsm->dlci[i]);
2054 /* Now wipe the queues */
2055 for (txq = gsm->tx_head; txq != NULL; txq = gsm->tx_head) {
2056 gsm->tx_head = txq->next;
2057 kfree(txq);
2058 }
2059 gsm->tx_tail = NULL;
2060}
2061EXPORT_SYMBOL_GPL(gsm_cleanup_mux);
2062
2063/**
2064 * gsm_activate_mux - generic GSM setup
2065 * @gsm: our mux
2066 *
2067 * Set up the bits of the mux which are the same for all framing
2068 * protocols. Add the mux to the mux table so it can be opened and
2069 * finally kick off connecting to DLCI 0 on the modem.
2070 */
2071
2072int gsm_activate_mux(struct gsm_mux *gsm)
2073{
2074 struct gsm_dlci *dlci;
2075 int i = 0;
2076
2077 init_timer(&gsm->t2_timer);
2078 gsm->t2_timer.function = gsm_control_retransmit;
2079 gsm->t2_timer.data = (unsigned long)gsm;
2080 init_waitqueue_head(&gsm->event);
2081 spin_lock_init(&gsm->control_lock);
2082 spin_lock_init(&gsm->tx_lock);
2083
2084 if (gsm->encoding == 0)
2085 gsm->receive = gsm0_receive;
2086 else
2087 gsm->receive = gsm1_receive;
2088 gsm->error = gsm_error;
2089
2090 spin_lock(&gsm_mux_lock);
2091 for (i = 0; i < MAX_MUX; i++) {
2092 if (gsm_mux[i] == NULL) {
2093 gsm->num = i;
2094 gsm_mux[i] = gsm;
2095 break;
2096 }
2097 }
2098 spin_unlock(&gsm_mux_lock);
2099 if (i == MAX_MUX)
2100 return -EBUSY;
2101
2102 dlci = gsm_dlci_alloc(gsm, 0);
2103 if (dlci == NULL)
2104 return -ENOMEM;
2105 gsm->dead = 0; /* Tty opens are now permissible */
2106 return 0;
2107}
2108EXPORT_SYMBOL_GPL(gsm_activate_mux);
2109
2110/**
2111 * gsm_free_mux - free up a mux
2112 * @mux: mux to free
2113 *
2114 * Dispose of allocated resources for a dead mux
2115 */
2116void gsm_free_mux(struct gsm_mux *gsm)
2117{
2118 kfree(gsm->txframe);
2119 kfree(gsm->buf);
2120 kfree(gsm);
2121}
2122EXPORT_SYMBOL_GPL(gsm_free_mux);
2123
2124/**
2125 * gsm_free_muxr - free up a mux
2126 * @mux: mux to free
2127 *
2128 * Dispose of allocated resources for a dead mux
2129 */
2130static void gsm_free_muxr(struct kref *ref)
2131{
2132 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref);
2133 gsm_free_mux(gsm);
2134}
2135
2136static inline void mux_get(struct gsm_mux *gsm)
2137{
2138 kref_get(&gsm->ref);
2139}
2140
2141static inline void mux_put(struct gsm_mux *gsm)
2142{
2143 kref_put(&gsm->ref, gsm_free_muxr);
2144}
2145
2146/**
2147 * gsm_alloc_mux - allocate a mux
2148 *
2149 * Creates a new mux ready for activation.
2150 */
2151
2152struct gsm_mux *gsm_alloc_mux(void)
2153{
2154 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
2155 if (gsm == NULL)
2156 return NULL;
2157 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL);
2158 if (gsm->buf == NULL) {
2159 kfree(gsm);
2160 return NULL;
2161 }
2162 gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL);
2163 if (gsm->txframe == NULL) {
2164 kfree(gsm->buf);
2165 kfree(gsm);
2166 return NULL;
2167 }
2168 spin_lock_init(&gsm->lock);
2169 kref_init(&gsm->ref);
2170
2171 gsm->t1 = T1;
2172 gsm->t2 = T2;
2173 gsm->n2 = N2;
2174 gsm->ftype = UIH;
2175 gsm->adaption = 1;
2176 gsm->encoding = 1;
2177 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
2178 gsm->mtu = 64;
2179 gsm->dead = 1; /* Avoid early tty opens */
2180
2181 return gsm;
2182}
2183EXPORT_SYMBOL_GPL(gsm_alloc_mux);
2184
2185/**
2186 * gsmld_output - write to link
2187 * @gsm: our mux
2188 * @data: bytes to output
2189 * @len: size
2190 *
2191 * Write a block of data from the GSM mux to the data channel. This
2192 * will eventually be serialized from above but at the moment isn't.
2193 */
2194
2195static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
2196{
2197 if (tty_write_room(gsm->tty) < len) {
2198 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
2199 return -ENOSPC;
2200 }
2201 if (debug & 4)
2202 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET,
2203 data, len);
2204 gsm->tty->ops->write(gsm->tty, data, len);
2205 return len;
2206}
2207
2208/**
2209 * gsmld_attach_gsm - mode set up
2210 * @tty: our tty structure
2211 * @gsm: our mux
2212 *
2213 * Set up the MUX for basic mode and commence connecting to the
2214 * modem. Currently called from the line discipline set up but
2215 * will need moving to an ioctl path.
2216 */
2217
2218static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2219{
2220 int ret, i;
2221 int base = gsm->num << 6; /* Base for this MUX */
2222
2223 gsm->tty = tty_kref_get(tty);
2224 gsm->output = gsmld_output;
2225 ret = gsm_activate_mux(gsm);
2226 if (ret != 0)
2227 tty_kref_put(gsm->tty);
2228 else {
2229 /* Don't register device 0 - this is the control channel and not
2230 a usable tty interface */
2231 for (i = 1; i < NUM_DLCI; i++)
2232 tty_register_device(gsm_tty_driver, base + i, NULL);
2233 }
2234 return ret;
2235}
2236
2237
2238/**
2239 * gsmld_detach_gsm - stop doing 0710 mux
2240 * @tty: tty attached to the mux
2241 * @gsm: mux
2242 *
2243 * Shutdown and then clean up the resources used by the line discipline
2244 */
2245
2246static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2247{
2248 int i;
2249 int base = gsm->num << 6; /* Base for this MUX */
2250
2251 WARN_ON(tty != gsm->tty);
2252 for (i = 1; i < NUM_DLCI; i++)
2253 tty_unregister_device(gsm_tty_driver, base + i);
2254 gsm_cleanup_mux(gsm);
2255 tty_kref_put(gsm->tty);
2256 gsm->tty = NULL;
2257}
2258
2259static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
2260 char *fp, int count)
2261{
2262 struct gsm_mux *gsm = tty->disc_data;
2263 const unsigned char *dp;
2264 char *f;
2265 int i;
2266 char buf[64];
2267 char flags;
2268
2269 if (debug & 4)
2270 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET,
2271 cp, count);
2272
2273 for (i = count, dp = cp, f = fp; i; i--, dp++) {
2274 flags = *f++;
2275 switch (flags) {
2276 case TTY_NORMAL:
2277 gsm->receive(gsm, *dp);
2278 break;
2279 case TTY_OVERRUN:
2280 case TTY_BREAK:
2281 case TTY_PARITY:
2282 case TTY_FRAME:
2283 gsm->error(gsm, *dp, flags);
2284 break;
2285 default:
2286 WARN_ONCE("%s: unknown flag %d\n",
2287 tty_name(tty, buf), flags);
2288 break;
2289 }
2290 }
2291 /* FASYNC if needed ? */
2292 /* If clogged call tty_throttle(tty); */
2293}
2294
2295/**
2296 * gsmld_chars_in_buffer - report available bytes
2297 * @tty: tty device
2298 *
2299 * Report the number of characters buffered to be delivered to user
2300 * at this instant in time.
2301 *
2302 * Locking: gsm lock
2303 */
2304
2305static ssize_t gsmld_chars_in_buffer(struct tty_struct *tty)
2306{
2307 return 0;
2308}
2309
2310/**
2311 * gsmld_flush_buffer - clean input queue
2312 * @tty: terminal device
2313 *
2314 * Flush the input buffer. Called when the line discipline is
2315 * being closed, when the tty layer wants the buffer flushed (eg
2316 * at hangup).
2317 */
2318
2319static void gsmld_flush_buffer(struct tty_struct *tty)
2320{
2321}
2322
2323/**
2324 * gsmld_close - close the ldisc for this tty
2325 * @tty: device
2326 *
2327 * Called from the terminal layer when this line discipline is
2328 * being shut down, either because of a close or becsuse of a
2329 * discipline change. The function will not be called while other
2330 * ldisc methods are in progress.
2331 */
2332
2333static void gsmld_close(struct tty_struct *tty)
2334{
2335 struct gsm_mux *gsm = tty->disc_data;
2336
2337 gsmld_detach_gsm(tty, gsm);
2338
2339 gsmld_flush_buffer(tty);
2340 /* Do other clean up here */
2341 mux_put(gsm);
2342}
2343
2344/**
2345 * gsmld_open - open an ldisc
2346 * @tty: terminal to open
2347 *
2348 * Called when this line discipline is being attached to the
2349 * terminal device. Can sleep. Called serialized so that no
2350 * other events will occur in parallel. No further open will occur
2351 * until a close.
2352 */
2353
2354static int gsmld_open(struct tty_struct *tty)
2355{
2356 struct gsm_mux *gsm;
2357
2358 if (tty->ops->write == NULL)
2359 return -EINVAL;
2360
2361 /* Attach our ldisc data */
2362 gsm = gsm_alloc_mux();
2363 if (gsm == NULL)
2364 return -ENOMEM;
2365
2366 tty->disc_data = gsm;
2367 tty->receive_room = 65536;
2368
2369 /* Attach the initial passive connection */
2370 gsm->encoding = 1;
2371 return gsmld_attach_gsm(tty, gsm);
2372}
2373
2374/**
2375 * gsmld_write_wakeup - asynchronous I/O notifier
2376 * @tty: tty device
2377 *
2378 * Required for the ptys, serial driver etc. since processes
2379 * that attach themselves to the master and rely on ASYNC
2380 * IO must be woken up
2381 */
2382
2383static void gsmld_write_wakeup(struct tty_struct *tty)
2384{
2385 struct gsm_mux *gsm = tty->disc_data;
2386 unsigned long flags;
2387
2388 /* Queue poll */
2389 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2390 spin_lock_irqsave(&gsm->tx_lock, flags);
2391 gsm_data_kick(gsm);
2392 if (gsm->tx_bytes < TX_THRESH_LO) {
2393 gsm_dlci_data_sweep(gsm);
2394 }
2395 spin_unlock_irqrestore(&gsm->tx_lock, flags);
2396}
2397
2398/**
2399 * gsmld_read - read function for tty
2400 * @tty: tty device
2401 * @file: file object
2402 * @buf: userspace buffer pointer
2403 * @nr: size of I/O
2404 *
2405 * Perform reads for the line discipline. We are guaranteed that the
2406 * line discipline will not be closed under us but we may get multiple
2407 * parallel readers and must handle this ourselves. We may also get
2408 * a hangup. Always called in user context, may sleep.
2409 *
2410 * This code must be sure never to sleep through a hangup.
2411 */
2412
2413static ssize_t gsmld_read(struct tty_struct *tty, struct file *file,
2414 unsigned char __user *buf, size_t nr)
2415{
2416 return -EOPNOTSUPP;
2417}
2418
2419/**
2420 * gsmld_write - write function for tty
2421 * @tty: tty device
2422 * @file: file object
2423 * @buf: userspace buffer pointer
2424 * @nr: size of I/O
2425 *
2426 * Called when the owner of the device wants to send a frame
2427 * itself (or some other control data). The data is transferred
2428 * as-is and must be properly framed and checksummed as appropriate
2429 * by userspace. Frames are either sent whole or not at all as this
2430 * avoids pain user side.
2431 */
2432
2433static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
2434 const unsigned char *buf, size_t nr)
2435{
2436 int space = tty_write_room(tty);
2437 if (space >= nr)
2438 return tty->ops->write(tty, buf, nr);
2439 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2440 return -ENOBUFS;
2441}
2442
2443/**
2444 * gsmld_poll - poll method for N_GSM0710
2445 * @tty: terminal device
2446 * @file: file accessing it
2447 * @wait: poll table
2448 *
2449 * Called when the line discipline is asked to poll() for data or
2450 * for special events. This code is not serialized with respect to
2451 * other events save open/close.
2452 *
2453 * This code must be sure never to sleep through a hangup.
2454 * Called without the kernel lock held - fine
2455 */
2456
2457static unsigned int gsmld_poll(struct tty_struct *tty, struct file *file,
2458 poll_table *wait)
2459{
2460 unsigned int mask = 0;
2461 struct gsm_mux *gsm = tty->disc_data;
2462
2463 poll_wait(file, &tty->read_wait, wait);
2464 poll_wait(file, &tty->write_wait, wait);
2465 if (tty_hung_up_p(file))
2466 mask |= POLLHUP;
2467 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
2468 mask |= POLLOUT | POLLWRNORM;
2469 if (gsm->dead)
2470 mask |= POLLHUP;
2471 return mask;
2472}
2473
2474static int gsmld_config(struct tty_struct *tty, struct gsm_mux *gsm,
2475 struct gsm_config *c)
2476{
2477 int need_close = 0;
2478 int need_restart = 0;
2479
2480 /* Stuff we don't support yet - UI or I frame transport, windowing */
2481 if ((c->adaption != 1 && c->adaption != 2) || c->k)
2482 return -EOPNOTSUPP;
2483 /* Check the MRU/MTU range looks sane */
2484 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8)
2485 return -EINVAL;
2486 if (c->n2 < 3)
2487 return -EINVAL;
2488 if (c->encapsulation > 1) /* Basic, advanced, no I */
2489 return -EINVAL;
2490 if (c->initiator > 1)
2491 return -EINVAL;
2492 if (c->i == 0 || c->i > 2) /* UIH and UI only */
2493 return -EINVAL;
2494 /*
2495 * See what is needed for reconfiguration
2496 */
2497
2498 /* Timing fields */
2499 if (c->t1 != 0 && c->t1 != gsm->t1)
2500 need_restart = 1;
2501 if (c->t2 != 0 && c->t2 != gsm->t2)
2502 need_restart = 1;
2503 if (c->encapsulation != gsm->encoding)
2504 need_restart = 1;
2505 if (c->adaption != gsm->adaption)
2506 need_restart = 1;
2507 /* Requires care */
2508 if (c->initiator != gsm->initiator)
2509 need_close = 1;
2510 if (c->mru != gsm->mru)
2511 need_restart = 1;
2512 if (c->mtu != gsm->mtu)
2513 need_restart = 1;
2514
2515 /*
2516 * Close down what is needed, restart and initiate the new
2517 * configuration
2518 */
2519
2520 if (need_close || need_restart) {
2521 gsm_dlci_begin_close(gsm->dlci[0]);
2522 /* This will timeout if the link is down due to N2 expiring */
2523 wait_event_interruptible(gsm->event,
2524 gsm->dlci[0]->state == DLCI_CLOSED);
2525 if (signal_pending(current))
2526 return -EINTR;
2527 }
2528 if (need_restart)
2529 gsm_cleanup_mux(gsm);
2530
2531 gsm->initiator = c->initiator;
2532 gsm->mru = c->mru;
2533 gsm->mtu = c->mtu;
2534 gsm->encoding = c->encapsulation;
2535 gsm->adaption = c->adaption;
2536 gsm->n2 = c->n2;
2537
2538 if (c->i == 1)
2539 gsm->ftype = UIH;
2540 else if (c->i == 2)
2541 gsm->ftype = UI;
2542
2543 if (c->t1)
2544 gsm->t1 = c->t1;
2545 if (c->t2)
2546 gsm->t2 = c->t2;
2547
2548 /* FIXME: We need to separate activation/deactivation from adding
2549 and removing from the mux array */
2550 if (need_restart)
2551 gsm_activate_mux(gsm);
2552 if (gsm->initiator && need_close)
2553 gsm_dlci_begin_open(gsm->dlci[0]);
2554 return 0;
2555}
2556
2557static int gsmld_ioctl(struct tty_struct *tty, struct file *file,
2558 unsigned int cmd, unsigned long arg)
2559{
2560 struct gsm_config c;
2561 struct gsm_mux *gsm = tty->disc_data;
2562
2563 switch (cmd) {
2564 case GSMIOC_GETCONF:
2565 memset(&c, 0, sizeof(c));
2566 c.adaption = gsm->adaption;
2567 c.encapsulation = gsm->encoding;
2568 c.initiator = gsm->initiator;
2569 c.t1 = gsm->t1;
2570 c.t2 = gsm->t2;
2571 c.t3 = 0; /* Not supported */
2572 c.n2 = gsm->n2;
2573 if (gsm->ftype == UIH)
2574 c.i = 1;
2575 else
2576 c.i = 2;
2577 pr_debug("Ftype %d i %d\n", gsm->ftype, c.i);
2578 c.mru = gsm->mru;
2579 c.mtu = gsm->mtu;
2580 c.k = 0;
2581 if (copy_to_user((void *)arg, &c, sizeof(c)))
2582 return -EFAULT;
2583 return 0;
2584 case GSMIOC_SETCONF:
2585 if (copy_from_user(&c, (void *)arg, sizeof(c)))
2586 return -EFAULT;
2587 return gsmld_config(tty, gsm, &c);
2588 default:
2589 return n_tty_ioctl_helper(tty, file, cmd, arg);
2590 }
2591}
2592
2593/*
2594 * Network interface
2595 *
2596 */
2597
2598static int gsm_mux_net_open(struct net_device *net)
2599{
2600 pr_debug("%s called\n", __func__);
2601 netif_start_queue(net);
2602 return 0;
2603}
2604
2605static int gsm_mux_net_close(struct net_device *net)
2606{
2607 netif_stop_queue(net);
2608 return 0;
2609}
2610
2611static struct net_device_stats *gsm_mux_net_get_stats(struct net_device *net)
2612{
2613 return &((struct gsm_mux_net *)netdev_priv(net))->stats;
2614}
2615static void dlci_net_free(struct gsm_dlci *dlci)
2616{
2617 if (!dlci->net) {
2618 WARN_ON(1);
2619 return;
2620 }
2621 dlci->adaption = dlci->prev_adaption;
2622 dlci->data = dlci->prev_data;
2623 free_netdev(dlci->net);
2624 dlci->net = NULL;
2625}
2626static void net_free(struct kref *ref)
2627{
2628 struct gsm_mux_net *mux_net;
2629 struct gsm_dlci *dlci;
2630
2631 mux_net = container_of(ref, struct gsm_mux_net, ref);
2632 dlci = mux_net->dlci;
2633
2634 if (dlci->net) {
2635 unregister_netdev(dlci->net);
2636 dlci_net_free(dlci);
2637 }
2638}
2639
2640static inline void muxnet_get(struct gsm_mux_net *mux_net)
2641{
2642 kref_get(&mux_net->ref);
2643}
2644
2645static inline void muxnet_put(struct gsm_mux_net *mux_net)
2646{
2647 kref_put(&mux_net->ref, net_free);
2648}
2649
2650static int gsm_mux_net_start_xmit(struct sk_buff *skb,
2651 struct net_device *net)
2652{
2653 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
2654 struct gsm_dlci *dlci = mux_net->dlci;
2655 muxnet_get(mux_net);
2656
2657 skb_queue_head(&dlci->skb_list, skb);
2658 STATS(net).tx_packets++;
2659 STATS(net).tx_bytes += skb->len;
2660 gsm_dlci_data_kick(dlci);
2661 /* And tell the kernel when the last transmit started. */
2662 net->trans_start = jiffies;
2663 muxnet_put(mux_net);
2664 return NETDEV_TX_OK;
2665}
2666
2667/* called when a packet did not ack after watchdogtimeout */
2668static void gsm_mux_net_tx_timeout(struct net_device *net)
2669{
2670 /* Tell syslog we are hosed. */
2671 dev_dbg(&net->dev, "Tx timed out.\n");
2672
2673 /* Update statistics */
2674 STATS(net).tx_errors++;
2675}
2676
2677static void gsm_mux_rx_netchar(struct gsm_dlci *dlci,
2678 unsigned char *in_buf, int size)
2679{
2680 struct net_device *net = dlci->net;
2681 struct sk_buff *skb;
2682 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
2683 muxnet_get(mux_net);
2684
2685 /* Allocate an sk_buff */
2686 skb = dev_alloc_skb(size + NET_IP_ALIGN);
2687 if (!skb) {
2688 /* We got no receive buffer. */
2689 STATS(net).rx_dropped++;
2690 muxnet_put(mux_net);
2691 return;
2692 }
2693 skb_reserve(skb, NET_IP_ALIGN);
2694 memcpy(skb_put(skb, size), in_buf, size);
2695
2696 skb->dev = net;
2697 skb->protocol = __constant_htons(ETH_P_IP);
2698
2699 /* Ship it off to the kernel */
2700 netif_rx(skb);
2701
2702 /* update out statistics */
2703 STATS(net).rx_packets++;
2704 STATS(net).rx_bytes += size;
2705 muxnet_put(mux_net);
2706 return;
2707}
2708
2709int gsm_change_mtu(struct net_device *net, int new_mtu)
2710{
2711 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
2712 if ((new_mtu < 8) || (new_mtu > mux_net->dlci->gsm->mtu))
2713 return -EINVAL;
2714 net->mtu = new_mtu;
2715 return 0;
2716}
2717
2718static void gsm_mux_net_init(struct net_device *net)
2719{
2720 static const struct net_device_ops gsm_netdev_ops = {
2721 .ndo_open = gsm_mux_net_open,
2722 .ndo_stop = gsm_mux_net_close,
2723 .ndo_start_xmit = gsm_mux_net_start_xmit,
2724 .ndo_tx_timeout = gsm_mux_net_tx_timeout,
2725 .ndo_get_stats = gsm_mux_net_get_stats,
2726 .ndo_change_mtu = gsm_change_mtu,
2727 };
2728
2729 net->netdev_ops = &gsm_netdev_ops;
2730
2731 /* fill in the other fields */
2732 net->watchdog_timeo = GSM_NET_TX_TIMEOUT;
2733 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
2734 net->type = ARPHRD_NONE;
2735 net->tx_queue_len = 10;
2736}
2737
2738
2739/* caller holds the dlci mutex */
2740static void gsm_destroy_network(struct gsm_dlci *dlci)
2741{
2742 struct gsm_mux_net *mux_net;
2743
2744 pr_debug("destroy network interface");
2745 if (!dlci->net)
2746 return;
2747 mux_net = (struct gsm_mux_net *)netdev_priv(dlci->net);
2748 muxnet_put(mux_net);
2749}
2750
2751
2752/* caller holds the dlci mutex */
2753static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
2754{
2755 char *netname;
2756 int retval = 0;
2757 struct net_device *net;
2758 struct gsm_mux_net *mux_net;
2759
2760 if (!capable(CAP_NET_ADMIN))
2761 return -EPERM;
2762
2763 /* Already in a non tty mode */
2764 if (dlci->adaption > 2)
2765 return -EBUSY;
2766
2767 if (nc->protocol != htons(ETH_P_IP))
2768 return -EPROTONOSUPPORT;
2769
2770 if (nc->adaption != 3 && nc->adaption != 4)
2771 return -EPROTONOSUPPORT;
2772
2773 pr_debug("create network interface");
2774
2775 netname = "gsm%d";
2776 if (nc->if_name[0] != '\0')
2777 netname = nc->if_name;
2778 net = alloc_netdev(sizeof(struct gsm_mux_net),
2779 netname,
2780 gsm_mux_net_init);
2781 if (!net) {
2782 pr_err("alloc_netdev failed");
2783 return -ENOMEM;
2784 }
2785 net->mtu = dlci->gsm->mtu;
2786 mux_net = (struct gsm_mux_net *)netdev_priv(net);
2787 mux_net->dlci = dlci;
2788 kref_init(&mux_net->ref);
2789 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */
2790
2791 /* reconfigure dlci for network */
2792 dlci->prev_adaption = dlci->adaption;
2793 dlci->prev_data = dlci->data;
2794 dlci->adaption = nc->adaption;
2795 dlci->data = gsm_mux_rx_netchar;
2796 dlci->net = net;
2797
2798 pr_debug("register netdev");
2799 retval = register_netdev(net);
2800 if (retval) {
2801 pr_err("network register fail %d\n", retval);
2802 dlci_net_free(dlci);
2803 return retval;
2804 }
2805 return net->ifindex; /* return network index */
2806}
2807
2808/* Line discipline for real tty */
2809struct tty_ldisc_ops tty_ldisc_packet = {
2810 .owner = THIS_MODULE,
2811 .magic = TTY_LDISC_MAGIC,
2812 .name = "n_gsm",
2813 .open = gsmld_open,
2814 .close = gsmld_close,
2815 .flush_buffer = gsmld_flush_buffer,
2816 .chars_in_buffer = gsmld_chars_in_buffer,
2817 .read = gsmld_read,
2818 .write = gsmld_write,
2819 .ioctl = gsmld_ioctl,
2820 .poll = gsmld_poll,
2821 .receive_buf = gsmld_receive_buf,
2822 .write_wakeup = gsmld_write_wakeup
2823};
2824
2825/*
2826 * Virtual tty side
2827 */
2828
2829#define TX_SIZE 512
2830
2831static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk)
2832{
2833 u8 modembits[5];
2834 struct gsm_control *ctrl;
2835 int len = 2;
2836
2837 if (brk)
2838 len++;
2839
2840 modembits[0] = len << 1 | EA; /* Data bytes */
2841 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */
2842 modembits[2] = gsm_encode_modem(dlci) << 1 | EA;
2843 if (brk)
2844 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */
2845 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1);
2846 if (ctrl == NULL)
2847 return -ENOMEM;
2848 return gsm_control_wait(dlci->gsm, ctrl);
2849}
2850
2851static int gsm_carrier_raised(struct tty_port *port)
2852{
2853 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2854 /* Not yet open so no carrier info */
2855 if (dlci->state != DLCI_OPEN)
2856 return 0;
2857 if (debug & 2)
2858 return 1;
2859 return dlci->modem_rx & TIOCM_CD;
2860}
2861
2862static void gsm_dtr_rts(struct tty_port *port, int onoff)
2863{
2864 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2865 unsigned int modem_tx = dlci->modem_tx;
2866 if (onoff)
2867 modem_tx |= TIOCM_DTR | TIOCM_RTS;
2868 else
2869 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
2870 if (modem_tx != dlci->modem_tx) {
2871 dlci->modem_tx = modem_tx;
2872 gsmtty_modem_update(dlci, 0);
2873 }
2874}
2875
2876static const struct tty_port_operations gsm_port_ops = {
2877 .carrier_raised = gsm_carrier_raised,
2878 .dtr_rts = gsm_dtr_rts,
2879};
2880
2881
2882static int gsmtty_open(struct tty_struct *tty, struct file *filp)
2883{
2884 struct gsm_mux *gsm;
2885 struct gsm_dlci *dlci;
2886 struct tty_port *port;
2887 unsigned int line = tty->index;
2888 unsigned int mux = line >> 6;
2889
2890 line = line & 0x3F;
2891
2892 if (mux >= MAX_MUX)
2893 return -ENXIO;
2894 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
2895 if (gsm_mux[mux] == NULL)
2896 return -EUNATCH;
2897 if (line == 0 || line > 61) /* 62/63 reserved */
2898 return -ECHRNG;
2899 gsm = gsm_mux[mux];
2900 if (gsm->dead)
2901 return -EL2HLT;
2902 /* If DLCI 0 is not yet fully open return an error. This is ok from a locking
2903 perspective as we don't have to worry about this if DLCI0 is lost */
2904 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN)
2905 return -EL2NSYNC;
2906 dlci = gsm->dlci[line];
2907 if (dlci == NULL)
2908 dlci = gsm_dlci_alloc(gsm, line);
2909 if (dlci == NULL)
2910 return -ENOMEM;
2911 port = &dlci->port;
2912 port->count++;
2913 tty->driver_data = dlci;
2914 dlci_get(dlci);
2915 dlci_get(dlci->gsm->dlci[0]);
2916 mux_get(dlci->gsm);
2917 tty_port_tty_set(port, tty);
2918
2919 dlci->modem_rx = 0;
2920 /* We could in theory open and close before we wait - eg if we get
2921 a DM straight back. This is ok as that will have caused a hangup */
2922 set_bit(ASYNCB_INITIALIZED, &port->flags);
2923 /* Start sending off SABM messages */
2924 gsm_dlci_begin_open(dlci);
2925 /* And wait for virtual carrier */
2926 return tty_port_block_til_ready(port, tty, filp);
2927}
2928
2929static void gsmtty_close(struct tty_struct *tty, struct file *filp)
2930{
2931 struct gsm_dlci *dlci = tty->driver_data;
2932 struct gsm_mux *gsm;
2933
2934 if (dlci == NULL)
2935 return;
2936 mutex_lock(&dlci->mutex);
2937 gsm_destroy_network(dlci);
2938 mutex_unlock(&dlci->mutex);
2939 gsm = dlci->gsm;
2940 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
2941 goto out;
2942 gsm_dlci_begin_close(dlci);
2943 tty_port_close_end(&dlci->port, tty);
2944 tty_port_tty_set(&dlci->port, NULL);
2945out:
2946 dlci_put(dlci);
2947 dlci_put(gsm->dlci[0]);
2948 mux_put(gsm);
2949}
2950
2951static void gsmtty_hangup(struct tty_struct *tty)
2952{
2953 struct gsm_dlci *dlci = tty->driver_data;
2954 tty_port_hangup(&dlci->port);
2955 gsm_dlci_begin_close(dlci);
2956}
2957
2958static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf,
2959 int len)
2960{
2961 struct gsm_dlci *dlci = tty->driver_data;
2962 /* Stuff the bytes into the fifo queue */
2963 int sent = kfifo_in_locked(dlci->fifo, buf, len, &dlci->lock);
2964 /* Need to kick the channel */
2965 gsm_dlci_data_kick(dlci);
2966 return sent;
2967}
2968
2969static int gsmtty_write_room(struct tty_struct *tty)
2970{
2971 struct gsm_dlci *dlci = tty->driver_data;
2972 return TX_SIZE - kfifo_len(dlci->fifo);
2973}
2974
2975static int gsmtty_chars_in_buffer(struct tty_struct *tty)
2976{
2977 struct gsm_dlci *dlci = tty->driver_data;
2978 return kfifo_len(dlci->fifo);
2979}
2980
2981static void gsmtty_flush_buffer(struct tty_struct *tty)
2982{
2983 struct gsm_dlci *dlci = tty->driver_data;
2984 /* Caution needed: If we implement reliable transport classes
2985 then the data being transmitted can't simply be junked once
2986 it has first hit the stack. Until then we can just blow it
2987 away */
2988 kfifo_reset(dlci->fifo);
2989 /* Need to unhook this DLCI from the transmit queue logic */
2990}
2991
2992static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
2993{
2994 /* The FIFO handles the queue so the kernel will do the right
2995 thing waiting on chars_in_buffer before calling us. No work
2996 to do here */
2997}
2998
2999static int gsmtty_tiocmget(struct tty_struct *tty)
3000{
3001 struct gsm_dlci *dlci = tty->driver_data;
3002 return dlci->modem_rx;
3003}
3004
3005static int gsmtty_tiocmset(struct tty_struct *tty,
3006 unsigned int set, unsigned int clear)
3007{
3008 struct gsm_dlci *dlci = tty->driver_data;
3009 unsigned int modem_tx = dlci->modem_tx;
3010
3011 modem_tx &= ~clear;
3012 modem_tx |= set;
3013
3014 if (modem_tx != dlci->modem_tx) {
3015 dlci->modem_tx = modem_tx;
3016 return gsmtty_modem_update(dlci, 0);
3017 }
3018 return 0;
3019}
3020
3021
3022static int gsmtty_ioctl(struct tty_struct *tty,
3023 unsigned int cmd, unsigned long arg)
3024{
3025 struct gsm_dlci *dlci = tty->driver_data;
3026 struct gsm_netconfig nc;
3027 int index;
3028
3029 switch (cmd) {
3030 case GSMIOC_ENABLE_NET:
3031 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc)))
3032 return -EFAULT;
3033 nc.if_name[IFNAMSIZ-1] = '\0';
3034 /* return net interface index or error code */
3035 mutex_lock(&dlci->mutex);
3036 index = gsm_create_network(dlci, &nc);
3037 mutex_unlock(&dlci->mutex);
3038 if (copy_to_user((void __user *)arg, &nc, sizeof(nc)))
3039 return -EFAULT;
3040 return index;
3041 case GSMIOC_DISABLE_NET:
3042 if (!capable(CAP_NET_ADMIN))
3043 return -EPERM;
3044 mutex_lock(&dlci->mutex);
3045 gsm_destroy_network(dlci);
3046 mutex_unlock(&dlci->mutex);
3047 return 0;
3048 default:
3049 return -ENOIOCTLCMD;
3050 }
3051}
3052
3053static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old)
3054{
3055 /* For the moment its fixed. In actual fact the speed information
3056 for the virtual channel can be propogated in both directions by
3057 the RPN control message. This however rapidly gets nasty as we
3058 then have to remap modem signals each way according to whether
3059 our virtual cable is null modem etc .. */
3060 tty_termios_copy_hw(tty->termios, old);
3061}
3062
3063static void gsmtty_throttle(struct tty_struct *tty)
3064{
3065 struct gsm_dlci *dlci = tty->driver_data;
3066 if (tty->termios->c_cflag & CRTSCTS)
3067 dlci->modem_tx &= ~TIOCM_DTR;
3068 dlci->throttled = 1;
3069 /* Send an MSC with DTR cleared */
3070 gsmtty_modem_update(dlci, 0);
3071}
3072
3073static void gsmtty_unthrottle(struct tty_struct *tty)
3074{
3075 struct gsm_dlci *dlci = tty->driver_data;
3076 if (tty->termios->c_cflag & CRTSCTS)
3077 dlci->modem_tx |= TIOCM_DTR;
3078 dlci->throttled = 0;
3079 /* Send an MSC with DTR set */
3080 gsmtty_modem_update(dlci, 0);
3081}
3082
3083static int gsmtty_break_ctl(struct tty_struct *tty, int state)
3084{
3085 struct gsm_dlci *dlci = tty->driver_data;
3086 int encode = 0; /* Off */
3087
3088 if (state == -1) /* "On indefinitely" - we can't encode this
3089 properly */
3090 encode = 0x0F;
3091 else if (state > 0) {
3092 encode = state / 200; /* mS to encoding */
3093 if (encode > 0x0F)
3094 encode = 0x0F; /* Best effort */
3095 }
3096 return gsmtty_modem_update(dlci, encode);
3097}
3098
3099
3100/* Virtual ttys for the demux */
3101static const struct tty_operations gsmtty_ops = {
3102 .open = gsmtty_open,
3103 .close = gsmtty_close,
3104 .write = gsmtty_write,
3105 .write_room = gsmtty_write_room,
3106 .chars_in_buffer = gsmtty_chars_in_buffer,
3107 .flush_buffer = gsmtty_flush_buffer,
3108 .ioctl = gsmtty_ioctl,
3109 .throttle = gsmtty_throttle,
3110 .unthrottle = gsmtty_unthrottle,
3111 .set_termios = gsmtty_set_termios,
3112 .hangup = gsmtty_hangup,
3113 .wait_until_sent = gsmtty_wait_until_sent,
3114 .tiocmget = gsmtty_tiocmget,
3115 .tiocmset = gsmtty_tiocmset,
3116 .break_ctl = gsmtty_break_ctl,
3117};
3118
3119
3120
3121static int __init gsm_init(void)
3122{
3123 /* Fill in our line protocol discipline, and register it */
3124 int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet);
3125 if (status != 0) {
3126 pr_err("n_gsm: can't register line discipline (err = %d)\n",
3127 status);
3128 return status;
3129 }
3130
3131 gsm_tty_driver = alloc_tty_driver(256);
3132 if (!gsm_tty_driver) {
3133 tty_unregister_ldisc(N_GSM0710);
3134 pr_err("gsm_init: tty allocation failed.\n");
3135 return -EINVAL;
3136 }
3137 gsm_tty_driver->driver_name = "gsmtty";
3138 gsm_tty_driver->name = "gsmtty";
3139 gsm_tty_driver->major = 0; /* Dynamic */
3140 gsm_tty_driver->minor_start = 0;
3141 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
3142 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
3143 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV
3144 | TTY_DRIVER_HARDWARE_BREAK;
3145 gsm_tty_driver->init_termios = tty_std_termios;
3146 /* Fixme */
3147 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
3148 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
3149
3150 spin_lock_init(&gsm_mux_lock);
3151
3152 if (tty_register_driver(gsm_tty_driver)) {
3153 put_tty_driver(gsm_tty_driver);
3154 tty_unregister_ldisc(N_GSM0710);
3155 pr_err("gsm_init: tty registration failed.\n");
3156 return -EBUSY;
3157 }
3158 pr_debug("gsm_init: loaded as %d,%d.\n",
3159 gsm_tty_driver->major, gsm_tty_driver->minor_start);
3160 return 0;
3161}
3162
3163static void __exit gsm_exit(void)
3164{
3165 int status = tty_unregister_ldisc(N_GSM0710);
3166 if (status != 0)
3167 pr_err("n_gsm: can't unregister line discipline (err = %d)\n",
3168 status);
3169 tty_unregister_driver(gsm_tty_driver);
3170 put_tty_driver(gsm_tty_driver);
3171}
3172
3173module_init(gsm_init);
3174module_exit(gsm_exit);
3175
3176
3177MODULE_LICENSE("GPL");
3178MODULE_ALIAS_LDISC(N_GSM0710);