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