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