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[linux-2.6-block.git] / drivers / tty / n_gsm.c
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e3b3d0f5 1// SPDX-License-Identifier: GPL-2.0
e1eaea46
AC		 2/*
3 * n_gsm.c GSM 0710 tty multiplexor
4 * Copyright (c) 2009/10 Intel Corporation
5 *
e1eaea46
AC		 6 * * THIS IS A DEVELOPMENT SNAPSHOT IT IS NOT A FINAL RELEASE *
7 *
8 * TO DO:
9 * Mostly done: ioctls for setting modes/timing
5f9a31d6 10 * Partly done: hooks so you can pull off frames to non tty devs
e1eaea46 11 * Restart DLCI 0 when it closes ?
e1eaea46
AC		 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>
174cd4b1 30#include <linux/sched/signal.h>
e1eaea46
AC		 31#include <linux/interrupt.h>
32#include <linux/tty.h>
e1eaea46
AC		 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>
bcd5abe2
RG		 48#include <net/arp.h>
49#include <linux/ip.h>
50#include <linux/netdevice.h>
51#include <linux/etherdevice.h>
e1eaea46 52#include <linux/gsmmux.h>
5ffa6e34 53#include "tty.h"
e1eaea46
AC		 54
55static int debug;
56module_param(debug, int, 0600);
57
a8d12007
AC		 58/* Defaults: these are from the specification */
59
60#define T1 10 /* 100mS */
61#define T2 34 /* 333mS */
62#define N2 3 /* Retry 3 times */
e1eaea46
AC		 63
64/* Use long timers for testing at low speed with debug on */
65#ifdef DEBUG_TIMING
a8d12007
AC		 66#define T1 100
67#define T2 200
e1eaea46
AC		 68#endif
69
5f9a31d6 70/*
25985edc 71 * Semi-arbitrary buffer size limits. 0710 is normally run with 32-64 byte
5f9a31d6
AC		 72 * limits so this is plenty
73 */
bcd5abe2
RG		 74#define MAX_MRU 1500
75#define MAX_MTU 1500
76#define GSM_NET_TX_TIMEOUT (HZ*10)
77
b410e35d 78/*
bcd5abe2 79 * struct gsm_mux_net - network interface
bcd5abe2
RG		 80 *
81 * Created when net interface is initialized.
724ac070 82 */
bcd5abe2
RG		 83struct gsm_mux_net {
84 struct kref ref;
85 struct gsm_dlci *dlci;
bcd5abe2
RG		 86};
87
e1eaea46
AC		 88/*
89 * Each block of data we have queued to go out is in the form of
25985edc 90 * a gsm_msg which holds everything we need in a link layer independent
e1eaea46
AC		 91 * format
92 */
93
94struct gsm_msg {
b4338e1e 95 struct list_head list;
e1eaea46
AC		 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 */
2f202d03 100 unsigned char buffer[];
e1eaea46
AC		 101};
102
72ae8cc1
JS		 103enum gsm_dlci_state {
104 DLCI_CLOSED,
105 DLCI_OPENING, /* Sending SABM not seen UA */
106 DLCI_OPEN, /* SABM/UA complete */
107 DLCI_CLOSING, /* Sending DISC not seen UA/DM */
108};
109
e1785996
JS		 110enum gsm_dlci_mode {
111 DLCI_MODE_ABM, /* Normal Asynchronous Balanced Mode */
112 DLCI_MODE_ADM, /* Asynchronous Disconnected Mode */
113};
114
e1eaea46
AC		 115/*
116 * Each active data link has a gsm_dlci structure associated which ties
117 * the link layer to an optional tty (if the tty side is open). To avoid
118 * complexity right now these are only ever freed up when the mux is
119 * shut down.
120 *
121 * At the moment we don't free DLCI objects until the mux is torn down
122 * this avoid object life time issues but might be worth review later.
123 */
124
125struct gsm_dlci {
126 struct gsm_mux *gsm;
127 int addr;
72ae8cc1 128 enum gsm_dlci_state state;
bcd5abe2 129 struct mutex mutex;
e1eaea46
AC		 130
131 /* Link layer */
e1785996 132 enum gsm_dlci_mode mode;
e1eaea46
AC		 133 spinlock_t lock; /* Protects the internal state */
134 struct timer_list t1; /* Retransmit timer for SABM and UA */
135 int retries;
136 /* Uplink tty if active */
137 struct tty_port port; /* The tty bound to this DLCI if there is one */
036bca1f 138 struct kfifo fifo; /* Queue fifo for the DLCI */
e1eaea46 139 int adaption; /* Adaption layer in use */
bcd5abe2 140 int prev_adaption;
e1eaea46
AC		 141 u32 modem_rx; /* Our incoming virtual modem lines */
142 u32 modem_tx; /* Our outgoing modem lines */
5677fcf3 143 bool dead; /* Refuse re-open */
e1eaea46 144 /* Flow control */
e9360b9a 145 bool throttled; /* Private copy of throttle state */
7a9ed9c0 146 bool constipated; /* Throttle status for outgoing */
e1eaea46
AC		 147 /* Packetised I/O */
148 struct sk_buff *skb; /* Frame being sent */
149 struct sk_buff_head skb_list; /* Queued frames */
150 /* Data handling callback */
4feb7a4a
TL		 151 void (*data)(struct gsm_dlci *dlci, const u8 *data, int len);
152 void (*prev_data)(struct gsm_dlci *dlci, const u8 *data, int len);
bcd5abe2 153 struct net_device *net; /* network interface, if created */
e1eaea46
AC		 154};
155
c33eecc7 156/* DLCI 0, 62/63 are special or reserved see gsmtty_open */
e1eaea46
AC		 157
158#define NUM_DLCI 64
159
160/*
161 * DLCI 0 is used to pass control blocks out of band of the data
162 * flow (and with a higher link priority). One command can be outstanding
163 * at a time and we use this structure to manage them. They are created
164 * and destroyed by the user context, and updated by the receive paths
165 * and timers
166 */
167
168struct gsm_control {
169 u8 cmd; /* Command we are issuing */
170 u8 *data; /* Data for the command in case we retransmit */
171 int len; /* Length of block for retransmission */
172 int done; /* Done flag */
173 int error; /* Error if any */
174};
175
329aa6e6
JS		 176enum gsm_mux_state {
177 GSM_SEARCH,
178 GSM_START,
179 GSM_ADDRESS,
180 GSM_CONTROL,
181 GSM_LEN,
182 GSM_DATA,
183 GSM_FCS,
184 GSM_OVERRUN,
185 GSM_LEN0,
186 GSM_LEN1,
187 GSM_SSOF,
188};
189
e1eaea46
AC		 190/*
191 * Each GSM mux we have is represented by this structure. If we are
192 * operating as an ldisc then we use this structure as our ldisc
193 * state. We need to sort out lifetimes and locking with respect
194 * to the gsm mux array. For now we don't free DLCI objects that
195 * have been instantiated until the mux itself is terminated.
196 *
197 * To consider further: tty open versus mux shutdown.
198 */
199
200struct gsm_mux {
201 struct tty_struct *tty; /* The tty our ldisc is bound to */
202 spinlock_t lock;
dfabf7ff 203 struct mutex mutex;
d50f6dca 204 unsigned int num;
6ab8fba7 205 struct kref ref;
e1eaea46
AC		 206
207 /* Events on the GSM channel */
208 wait_queue_head_t event;
209
210 /* Bits for GSM mode decoding */
211
212 /* Framing Layer */
213 unsigned char *buf;
329aa6e6 214 enum gsm_mux_state state;
e1eaea46
AC		 215 unsigned int len;
216 unsigned int address;
217 unsigned int count;
c50704bd 218 bool escape;
e1eaea46
AC		 219 int encoding;
220 u8 control;
221 u8 fcs;
c2f2f000 222 u8 received_fcs;
e1eaea46
AC		 223 u8 *txframe; /* TX framing buffer */
224
a579767c 225 /* Method for the receiver side */
e1eaea46 226 void (*receive)(struct gsm_mux *gsm, u8 ch);
e1eaea46
AC		 227
228 /* Link Layer */
229 unsigned int mru;
230 unsigned int mtu;
231 int initiator; /* Did we initiate connection */
5677fcf3 232 bool dead; /* Has the mux been shut down */
e1eaea46 233 struct gsm_dlci *dlci[NUM_DLCI];
7a9ed9c0 234 bool constipated; /* Asked by remote to shut up */
e1eaea46
AC		 235
236 spinlock_t tx_lock;
237 unsigned int tx_bytes; /* TX data outstanding */
238#define TX_THRESH_HI 8192
239#define TX_THRESH_LO 2048
b4338e1e 240 struct list_head tx_list; /* Pending data packets */
e1eaea46
AC		 241
242 /* Control messages */
243 struct timer_list t2_timer; /* Retransmit timer for commands */
244 int cretries; /* Command retry counter */
245 struct gsm_control *pending_cmd;/* Our current pending command */
246 spinlock_t control_lock; /* Protects the pending command */
247
248 /* Configuration */
249 int adaption; /* 1 or 2 supported */
250 u8 ftype; /* UI or UIH */
251 int t1, t2; /* Timers in 1/100th of a sec */
252 int n2; /* Retry count */
253
254 /* Statistics (not currently exposed) */
255 unsigned long bad_fcs;
256 unsigned long malformed;
257 unsigned long io_error;
258 unsigned long bad_size;
259 unsigned long unsupported;
260};
261
262
263/*
264 * Mux objects - needed so that we can translate a tty index into the
265 * relevant mux and DLCI.
266 */
267
268#define MAX_MUX 4 /* 256 minors */
269static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */
399d44a1 270static DEFINE_SPINLOCK(gsm_mux_lock);
e1eaea46 271
d50f6dca
RG		 272static struct tty_driver *gsm_tty_driver;
273
0b91b533
ZZ		 274/* Save dlci open address */
275static int addr_open[256] = { 0 };
276/* Save dlci open count */
277static int addr_cnt;
e1eaea46
AC		 278/*
279 * This section of the driver logic implements the GSM encodings
280 * both the basic and the 'advanced'. Reliable transport is not
281 * supported.
282 */
283
284#define CR 0x02
285#define EA 0x01
286#define PF 0x10
287
288/* I is special: the rest are ..*/
289#define RR 0x01
290#define UI 0x03
291#define RNR 0x05
292#define REJ 0x09
293#define DM 0x0F
294#define SABM 0x2F
295#define DISC 0x43
296#define UA 0x63
297#define UIH 0xEF
298
299/* Channel commands */
300#define CMD_NSC 0x09
301#define CMD_TEST 0x11
302#define CMD_PSC 0x21
303#define CMD_RLS 0x29
304#define CMD_FCOFF 0x31
305#define CMD_PN 0x41
306#define CMD_RPN 0x49
307#define CMD_FCON 0x51
308#define CMD_CLD 0x61
309#define CMD_SNC 0x69
310#define CMD_MSC 0x71
311
312/* Virtual modem bits */
313#define MDM_FC 0x01
314#define MDM_RTC 0x02
315#define MDM_RTR 0x04
316#define MDM_IC 0x20
317#define MDM_DV 0x40
318
319#define GSM0_SOF 0xF9
5f9a31d6 320#define GSM1_SOF 0x7E
e1eaea46
AC		 321#define GSM1_ESCAPE 0x7D
322#define GSM1_ESCAPE_BITS 0x20
323#define XON 0x11
324#define XOFF 0x13
325
326static const struct tty_port_operations gsm_port_ops;
327
328/*
329 * CRC table for GSM 0710
330 */
331
332static const u8 gsm_fcs8[256] = {
333 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75,
334 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B,
335 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69,
336 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67,
337 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D,
338 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43,
339 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51,
340 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F,
341 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05,
342 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B,
343 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19,
344 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17,
345 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D,
346 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33,
347 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21,
348 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F,
349 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95,
350 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B,
351 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89,
352 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87,
353 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD,
354 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3,
355 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1,
356 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF,
357 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5,
358 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB,
359 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9,
360 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7,
361 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD,
362 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3,
363 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1,
364 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF
365};
366
367#define INIT_FCS 0xFF
368#define GOOD_FCS 0xCF
369
a579767c
JS		 370static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len);
371
e1eaea46
AC		 372/**
373 * gsm_fcs_add - update FCS
374 * @fcs: Current FCS
375 * @c: Next data
376 *
377 * Update the FCS to include c. Uses the algorithm in the specification
378 * notes.
379 */
380
381static inline u8 gsm_fcs_add(u8 fcs, u8 c)
382{
383 return gsm_fcs8[fcs ^ c];
384}
385
386/**
387 * gsm_fcs_add_block - update FCS for a block
388 * @fcs: Current FCS
389 * @c: buffer of data
390 * @len: length of buffer
391 *
392 * Update the FCS to include c. Uses the algorithm in the specification
393 * notes.
394 */
395
396static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len)
397{
398 while (len--)
399 fcs = gsm_fcs8[fcs ^ *c++];
400 return fcs;
401}
402
403/**
404 * gsm_read_ea - read a byte into an EA
405 * @val: variable holding value
724ac070 406 * @c: byte going into the EA
e1eaea46
AC		 407 *
408 * Processes one byte of an EA. Updates the passed variable
409 * and returns 1 if the EA is now completely read
410 */
411
412static int gsm_read_ea(unsigned int *val, u8 c)
413{
414 /* Add the next 7 bits into the value */
415 *val <<= 7;
416 *val |= c >> 1;
417 /* Was this the last byte of the EA 1 = yes*/
418 return c & EA;
419}
420
421/**
422 * gsm_encode_modem - encode modem data bits
423 * @dlci: DLCI to encode from
424 *
425 * Returns the correct GSM encoded modem status bits (6 bit field) for
426 * the current status of the DLCI and attached tty object
427 */
428
429static u8 gsm_encode_modem(const struct gsm_dlci *dlci)
430{
431 u8 modembits = 0;
432 /* FC is true flow control not modem bits */
433 if (dlci->throttled)
434 modembits |= MDM_FC;
435 if (dlci->modem_tx & TIOCM_DTR)
436 modembits |= MDM_RTC;
437 if (dlci->modem_tx & TIOCM_RTS)
438 modembits |= MDM_RTR;
439 if (dlci->modem_tx & TIOCM_RI)
440 modembits |= MDM_IC;
441 if (dlci->modem_tx & TIOCM_CD)
442 modembits |= MDM_DV;
443 return modembits;
444}
445
446/**
447 * gsm_print_packet - display a frame for debug
448 * @hdr: header to print before decode
449 * @addr: address EA from the frame
450 * @cr: C/R bit from the frame
451 * @control: control including PF bit
452 * @data: following data bytes
453 * @dlen: length of data
454 *
455 * Displays a packet in human readable format for debugging purposes. The
456 * style is based on amateur radio LAP-B dump display.
457 */
458
459static void gsm_print_packet(const char *hdr, int addr, int cr,
460 u8 control, const u8 *data, int dlen)
461{
462 if (!(debug & 1))
463 return;
464
5f9a31d6 465 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]);
e1eaea46
AC		 466
467 switch (control & ~PF) {
468 case SABM:
5f9a31d6 469 pr_cont("SABM");
e1eaea46
AC		 470 break;
471 case UA:
5f9a31d6 472 pr_cont("UA");
e1eaea46
AC		 473 break;
474 case DISC:
5f9a31d6 475 pr_cont("DISC");
e1eaea46
AC		 476 break;
477 case DM:
5f9a31d6 478 pr_cont("DM");
e1eaea46
AC		 479 break;
480 case UI:
5f9a31d6 481 pr_cont("UI");
e1eaea46
AC		 482 break;
483 case UIH:
5f9a31d6 484 pr_cont("UIH");
e1eaea46
AC		 485 break;
486 default:
487 if (!(control & 0x01)) {
5f9a31d6 488 pr_cont("I N(S)%d N(R)%d",
47fdd641 489 (control & 0x0E) >> 1, (control & 0xE0) >> 5);
e1eaea46 490 } else switch (control & 0x0F) {
5f9a31d6
AC		 491 case RR:
492 pr_cont("RR(%d)", (control & 0xE0) >> 5);
493 break;
494 case RNR:
495 pr_cont("RNR(%d)", (control & 0xE0) >> 5);
496 break;
497 case REJ:
498 pr_cont("REJ(%d)", (control & 0xE0) >> 5);
499 break;
500 default:
501 pr_cont("[%02X]", control);
e1eaea46
AC		 502 }
503 }
504
505 if (control & PF)
5f9a31d6 506 pr_cont("(P)");
e1eaea46 507 else
5f9a31d6 508 pr_cont("(F)");
e1eaea46 509
57626ff1 510 print_hex_dump_bytes("", DUMP_PREFIX_NONE, data, dlen);
e1eaea46
AC		 511}
512
513
514/*
515 * Link level transmission side
516 */
517
518/**
542a121a 519 * gsm_stuff_frame - bytestuff a packet
724ac070
JS		 520 * @input: input buffer
521 * @output: output buffer
e1eaea46
AC		 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
e1eaea46
AC		 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 }
a579767c 593 gsmld_output(gsm, cbuf, len);
f999c3b3
ZZ		 594 if (!gsm->initiator) {
595 cr = cr & gsm->initiator;
596 control = control & ~PF;
597 }
e1eaea46
AC		 598 gsm_print_packet("-->", addr, cr, control, NULL, 0);
599}
600
601/**
602 * gsm_response - send a control response
603 * @gsm: our GSM mux
604 * @addr: address for control frame
605 * @control: control byte including PF bit
606 *
607 * Format up and transmit a link level response frame.
608 */
609
610static inline void gsm_response(struct gsm_mux *gsm, int addr, int control)
611{
cc0f4212 612 gsm_send(gsm, addr, 1, control);
e1eaea46
AC		 613}
614
615/**
616 * gsm_command - send a control command
617 * @gsm: our GSM mux
618 * @addr: address for control frame
619 * @control: control byte including PF bit
620 *
621 * Format up and transmit a link level command frame.
622 */
623
624static inline void gsm_command(struct gsm_mux *gsm, int addr, int control)
625{
626 gsm_send(gsm, addr, 1, control);
627}
628
629/* Data transmission */
630
631#define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */
632
633/**
634 * gsm_data_alloc - allocate data frame
635 * @gsm: GSM mux
636 * @addr: DLCI address
637 * @len: length excluding header and FCS
638 * @ctrl: control byte
639 *
640 * Allocate a new data buffer for sending frames with data. Space is left
641 * at the front for header bytes but that is treated as an implementation
642 * detail and not for the high level code to use
643 */
644
645static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
646 u8 ctrl)
647{
648 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN,
649 GFP_ATOMIC);
650 if (m == NULL)
651 return NULL;
652 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */
653 m->len = len;
654 m->addr = addr;
655 m->ctrl = ctrl;
b4338e1e 656 INIT_LIST_HEAD(&m->list);
e1eaea46
AC		 657 return m;
658}
659
660/**
661 * gsm_data_kick - poke the queue
662 * @gsm: GSM Mux
b410e35d 663 * @dlci: DLCI sending the data
e1eaea46
AC		 664 *
665 * The tty device has called us to indicate that room has appeared in
666 * the transmit queue. Ram more data into the pipe if we have any
c01af4fe
FB		 667 * If we have been flow-stopped by a CMD_FCOFF, then we can only
668 * send messages on DLCI0 until CMD_FCON
e1eaea46
AC		 669 *
670 * FIXME: lock against link layer control transmissions
671 */
672
01dbb362 673static void gsm_data_kick(struct gsm_mux *gsm, struct gsm_dlci *dlci)
e1eaea46 674{
b4338e1e 675 struct gsm_msg *msg, *nmsg;
e1eaea46 676 int len;
e1eaea46 677
b4338e1e
RG		 678 list_for_each_entry_safe(msg, nmsg, &gsm->tx_list, list) {
679 if (gsm->constipated && msg->addr)
c01af4fe 680 continue;
e1eaea46
AC		 681 if (gsm->encoding != 0) {
682 gsm->txframe[0] = GSM1_SOF;
683 len = gsm_stuff_frame(msg->data,
684 gsm->txframe + 1, msg->len);
685 gsm->txframe[len + 1] = GSM1_SOF;
686 len += 2;
687 } else {
688 gsm->txframe[0] = GSM0_SOF;
689 memcpy(gsm->txframe + 1 , msg->data, msg->len);
690 gsm->txframe[msg->len + 1] = GSM0_SOF;
691 len = msg->len + 2;
692 }
693
0a77c4f9
JP		 694 if (debug & 4)
695 print_hex_dump_bytes("gsm_data_kick: ",
696 DUMP_PREFIX_OFFSET,
697 gsm->txframe, len);
9136c683 698 if (gsmld_output(gsm, gsm->txframe, len) <= 0)
e1eaea46
AC		 699 break;
700 /* FIXME: Can eliminate one SOF in many more cases */
e1eaea46 701 gsm->tx_bytes -= msg->len;
c01af4fe 702
b4338e1e
RG		 703 list_del(&msg->list);
704 kfree(msg);
01dbb362
GC		 705
706 if (dlci) {
707 tty_port_tty_wakeup(&dlci->port);
708 } else {
709 int i = 0;
710
4dd31f1f
GC		 711 for (i = 0; i < NUM_DLCI; i++)
712 if (gsm->dlci[i])
713 tty_port_tty_wakeup(&gsm->dlci[i]->port);
01dbb362 714 }
e1eaea46
AC		 715 }
716}
717
718/**
719 * __gsm_data_queue - queue a UI or UIH frame
720 * @dlci: DLCI sending the data
721 * @msg: message queued
722 *
723 * Add data to the transmit queue and try and get stuff moving
724 * out of the mux tty if not already doing so. The Caller must hold
725 * the gsm tx lock.
726 */
727
728static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
729{
730 struct gsm_mux *gsm = dlci->gsm;
731 u8 *dp = msg->data;
732 u8 *fcs = dp + msg->len;
733
734 /* Fill in the header */
735 if (gsm->encoding == 0) {
736 if (msg->len < 128)
737 *--dp = (msg->len << 1) | EA;
738 else {
be7a7411
KM		 739 *--dp = (msg->len >> 7); /* bits 7 - 15 */
740 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */
e1eaea46
AC		 741 }
742 }
743
744 *--dp = msg->ctrl;
745 if (gsm->initiator)
746 *--dp = (msg->addr << 2) | 2 | EA;
747 else
748 *--dp = (msg->addr << 2) | EA;
749 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp);
750 /* Ugly protocol layering violation */
751 if (msg->ctrl == UI || msg->ctrl == (UI|PF))
752 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len);
753 *fcs = 0xFF - *fcs;
754
755 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl,
756 msg->data, msg->len);
757
758 /* Move the header back and adjust the length, also allow for the FCS
759 now tacked on the end */
760 msg->len += (msg->data - dp) + 1;
761 msg->data = dp;
762
763 /* Add to the actual output queue */
b4338e1e 764 list_add_tail(&msg->list, &gsm->tx_list);
e1eaea46 765 gsm->tx_bytes += msg->len;
01dbb362 766 gsm_data_kick(gsm, dlci);
e1eaea46
AC		 767}
768
769/**
770 * gsm_data_queue - queue a UI or UIH frame
771 * @dlci: DLCI sending the data
772 * @msg: message queued
773 *
774 * Add data to the transmit queue and try and get stuff moving
775 * out of the mux tty if not already doing so. Take the
776 * the gsm tx lock and dlci lock.
777 */
778
779static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
780{
781 unsigned long flags;
782 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
783 __gsm_data_queue(dlci, msg);
784 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
785}
786
787/**
788 * gsm_dlci_data_output - try and push data out of a DLCI
789 * @gsm: mux
790 * @dlci: the DLCI to pull data from
791 *
792 * Pull data from a DLCI and send it into the transmit queue if there
793 * is data. Keep to the MRU of the mux. This path handles the usual tty
794 * interface which is a byte stream with optional modem data.
795 *
796 * Caller must hold the tx_lock of the mux.
797 */
798
799static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci)
800{
801 struct gsm_msg *msg;
802 u8 *dp;
268e526b 803 int len, total_size, size;
e1eaea46
AC		 804 int h = dlci->adaption - 1;
805
268e526b 806 total_size = 0;
f3c909b4 807 while (1) {
036bca1f 808 len = kfifo_len(&dlci->fifo);
268e526b
MK		 809 if (len == 0)
810 return total_size;
811
812 /* MTU/MRU count only the data bits */
813 if (len > gsm->mtu)
814 len = gsm->mtu;
815
816 size = len + h;
817
818 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
819 /* FIXME: need a timer or something to kick this so it can't
820 get stuck with no work outstanding and no buffer free */
821 if (msg == NULL)
822 return -ENOMEM;
823 dp = msg->data;
824 switch (dlci->adaption) {
825 case 1: /* Unstructured */
826 break;
f3c909b4
AI		 827 case 2: /* Unstructed with modem bits.
828 Always one byte as we never send inline break data */
268e526b
MK		 829 *dp++ = gsm_encode_modem(dlci);
830 break;
831 }
036bca1f 832 WARN_ON(kfifo_out_locked(&dlci->fifo, dp , len, &dlci->lock) != len);
268e526b
MK		 833 __gsm_data_queue(dlci, msg);
834 total_size += size;
e1eaea46 835 }
e1eaea46 836 /* Bytes of data we used up */
268e526b 837 return total_size;
e1eaea46
AC		 838}
839
840/**
841 * gsm_dlci_data_output_framed - try and push data out of a DLCI
842 * @gsm: mux
843 * @dlci: the DLCI to pull data from
844 *
845 * Pull data from a DLCI and send it into the transmit queue if there
846 * is data. Keep to the MRU of the mux. This path handles framed data
847 * queued as skbuffs to the DLCI.
848 *
849 * Caller must hold the tx_lock of the mux.
850 */
851
852static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
853 struct gsm_dlci *dlci)
854{
855 struct gsm_msg *msg;
856 u8 *dp;
857 int len, size;
858 int last = 0, first = 0;
859 int overhead = 0;
860
861 /* One byte per frame is used for B/F flags */
862 if (dlci->adaption == 4)
863 overhead = 1;
864
865 /* dlci->skb is locked by tx_lock */
866 if (dlci->skb == NULL) {
88ed2a60 867 dlci->skb = skb_dequeue_tail(&dlci->skb_list);
e1eaea46
AC		 868 if (dlci->skb == NULL)
869 return 0;
870 first = 1;
871 }
872 len = dlci->skb->len + overhead;
873
874 /* MTU/MRU count only the data bits */
875 if (len > gsm->mtu) {
876 if (dlci->adaption == 3) {
877 /* Over long frame, bin it */
329e5678 878 dev_kfree_skb_any(dlci->skb);
e1eaea46
AC		 879 dlci->skb = NULL;
880 return 0;
881 }
882 len = gsm->mtu;
883 } else
884 last = 1;
885
886 size = len + overhead;
887 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
888
889 /* FIXME: need a timer or something to kick this so it can't
890 get stuck with no work outstanding and no buffer free */
88ed2a60
RG		 891 if (msg == NULL) {
892 skb_queue_tail(&dlci->skb_list, dlci->skb);
893 dlci->skb = NULL;
e1eaea46 894 return -ENOMEM;
88ed2a60 895 }
e1eaea46
AC		 896 dp = msg->data;
897
898 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */
899 /* Flag byte to carry the start/end info */
900 *dp++ = last << 7 | first << 6 | 1; /* EA */
901 len--;
902 }
57f2104f
RG		 903 memcpy(dp, dlci->skb->data, len);
904 skb_pull(dlci->skb, len);
e1eaea46 905 __gsm_data_queue(dlci, msg);
bcd5abe2 906 if (last) {
329e5678 907 dev_kfree_skb_any(dlci->skb);
e1eaea46 908 dlci->skb = NULL;
bcd5abe2 909 }
e1eaea46
AC		 910 return size;
911}
912
913/**
914 * gsm_dlci_data_sweep - look for data to send
915 * @gsm: the GSM mux
916 *
917 * Sweep the GSM mux channels in priority order looking for ones with
918 * data to send. We could do with optimising this scan a bit. We aim
919 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit
920 * TX_THRESH_LO we get called again
921 *
922 * FIXME: We should round robin between groups and in theory you can
923 * renegotiate DLCI priorities with optional stuff. Needs optimising.
924 */
925
926static void gsm_dlci_data_sweep(struct gsm_mux *gsm)
927{
928 int len;
929 /* Priority ordering: We should do priority with RR of the groups */
930 int i = 1;
e1eaea46 931
e1eaea46
AC		 932 while (i < NUM_DLCI) {
933 struct gsm_dlci *dlci;
934
935 if (gsm->tx_bytes > TX_THRESH_HI)
936 break;
937 dlci = gsm->dlci[i];
938 if (dlci == NULL || dlci->constipated) {
939 i++;
940 continue;
941 }
bcd5abe2 942 if (dlci->adaption < 3 && !dlci->net)
e1eaea46
AC		 943 len = gsm_dlci_data_output(gsm, dlci);
944 else
945 len = gsm_dlci_data_output_framed(gsm, dlci);
946 if (len < 0)
e73790a5 947 break;
e1eaea46
AC		 948 /* DLCI empty - try the next */
949 if (len == 0)
950 i++;
951 }
e1eaea46
AC		 952}
953
954/**
955 * gsm_dlci_data_kick - transmit if possible
956 * @dlci: DLCI to kick
957 *
958 * Transmit data from this DLCI if the queue is empty. We can't rely on
959 * a tty wakeup except when we filled the pipe so we need to fire off
960 * new data ourselves in other cases.
961 */
962
963static void gsm_dlci_data_kick(struct gsm_dlci *dlci)
964{
965 unsigned long flags;
192b6041 966 int sweep;
e1eaea46 967
f3c909b4 968 if (dlci->constipated)
c01af4fe 969 return;
c01af4fe 970
e1eaea46
AC		 971 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
972 /* If we have nothing running then we need to fire up */
192b6041 973 sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO);
bcd5abe2
RG		 974 if (dlci->gsm->tx_bytes == 0) {
975 if (dlci->net)
976 gsm_dlci_data_output_framed(dlci->gsm, dlci);
977 else
978 gsm_dlci_data_output(dlci->gsm, dlci);
192b6041
RG		 979 }
980 if (sweep)
f3c909b4 981 gsm_dlci_data_sweep(dlci->gsm);
e1eaea46
AC		 982 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
983}
984
985/*
986 * Control message processing
987 */
988
989
990/**
991 * gsm_control_reply - send a response frame to a control
992 * @gsm: gsm channel
993 * @cmd: the command to use
994 * @data: data to follow encoded info
995 * @dlen: length of data
996 *
997 * Encode up and queue a UI/UIH frame containing our response.
998 */
999
4feb7a4a 1000static void gsm_control_reply(struct gsm_mux *gsm, int cmd, const u8 *data,
e1eaea46
AC		 1001 int dlen)
1002{
1003 struct gsm_msg *msg;
1004 msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype);
093d8046
KM		 1005 if (msg == NULL)
1006 return;
e1eaea46
AC		 1007 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */
1008 msg->data[1] = (dlen << 1) | EA;
1009 memcpy(msg->data + 2, data, dlen);
1010 gsm_data_queue(gsm->dlci[0], msg);
1011}
1012
1013/**
1014 * gsm_process_modem - process received modem status
1015 * @tty: virtual tty bound to the DLCI
1016 * @dlci: DLCI to affect
1017 * @modem: modem bits (full EA)
b410e35d 1018 * @clen: command length
e1eaea46
AC		 1019 *
1020 * Used when a modem control message or line state inline in adaption
1021 * layer 2 is processed. Sort out the local modem state and throttles
1022 */
1023
1024static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
7263287a 1025 u32 modem, int clen)
e1eaea46
AC		 1026{
1027 int mlines = 0;
7263287a 1028 u8 brk = 0;
c01af4fe 1029 int fc;
7263287a
RG		 1030
1031 /* The modem status command can either contain one octet (v.24 signals)
1032 or two octets (v.24 signals + break signals). The length field will
1033 either be 2 or 3 respectively. This is specified in section
1034 5.4.6.3.7 of the 27.010 mux spec. */
1035
1036 if (clen == 2)
1037 modem = modem & 0x7f;
1038 else {
1039 brk = modem & 0x7f;
1040 modem = (modem >> 7) & 0x7f;
c01af4fe 1041 }
e1eaea46
AC		 1042
1043 /* Flow control/ready to communicate */
c01af4fe
FB		 1044 fc = (modem & MDM_FC) || !(modem & MDM_RTR);
1045 if (fc && !dlci->constipated) {
e1eaea46 1046 /* Need to throttle our output on this device */
7a9ed9c0 1047 dlci->constipated = true;
c01af4fe 1048 } else if (!fc && dlci->constipated) {
7a9ed9c0 1049 dlci->constipated = false;
e1eaea46
AC		 1050 gsm_dlci_data_kick(dlci);
1051 }
c01af4fe 1052
e1eaea46 1053 /* Map modem bits */
c01af4fe
FB		 1054 if (modem & MDM_RTC)
1055 mlines |= TIOCM_DSR | TIOCM_DTR;
e1eaea46
AC		 1056 if (modem & MDM_RTR)
1057 mlines |= TIOCM_RTS | TIOCM_CTS;
1058 if (modem & MDM_IC)
1059 mlines |= TIOCM_RI;
1060 if (modem & MDM_DV)
1061 mlines |= TIOCM_CD;
1062
1063 /* Carrier drop -> hangup */
1064 if (tty) {
1065 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD))
9db276f8 1066 if (!C_CLOCAL(tty))
e1eaea46 1067 tty_hangup(tty);
e1eaea46 1068 }
92a19f9c
JS		 1069 if (brk & 0x01)
1070 tty_insert_flip_char(&dlci->port, 0, TTY_BREAK);
e1eaea46
AC		 1071 dlci->modem_rx = mlines;
1072}
1073
1074/**
1075 * gsm_control_modem - modem status received
1076 * @gsm: GSM channel
1077 * @data: data following command
1078 * @clen: command length
1079 *
1080 * We have received a modem status control message. This is used by
1081 * the GSM mux protocol to pass virtual modem line status and optionally
1082 * to indicate break signals. Unpack it, convert to Linux representation
1083 * and if need be stuff a break message down the tty.
1084 */
1085
4feb7a4a 1086static void gsm_control_modem(struct gsm_mux *gsm, const u8 *data, int clen)
e1eaea46
AC		 1087{
1088 unsigned int addr = 0;
1089 unsigned int modem = 0;
3ac06b90 1090 unsigned int brk = 0;
e1eaea46
AC		 1091 struct gsm_dlci *dlci;
1092 int len = clen;
4feb7a4a 1093 const u8 *dp = data;
e1eaea46
AC		 1094 struct tty_struct *tty;
1095
1096 while (gsm_read_ea(&addr, *dp++) == 0) {
1097 len--;
1098 if (len == 0)
1099 return;
1100 }
1101 /* Must be at least one byte following the EA */
1102 len--;
1103 if (len <= 0)
1104 return;
1105
1106 addr >>= 1;
1107 /* Closed port, or invalid ? */
1108 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1109 return;
1110 dlci = gsm->dlci[addr];
1111
1112 while (gsm_read_ea(&modem, *dp++) == 0) {
1113 len--;
1114 if (len == 0)
1115 return;
1116 }
3ac06b90
LP		 1117 len--;
1118 if (len > 0) {
1119 while (gsm_read_ea(&brk, *dp++) == 0) {
1120 len--;
1121 if (len == 0)
1122 return;
1123 }
1124 modem <<= 7;
1125 modem |= (brk & 0x7f);
1126 }
e1eaea46 1127 tty = tty_port_tty_get(&dlci->port);
7263287a 1128 gsm_process_modem(tty, dlci, modem, clen);
e1eaea46
AC		 1129 if (tty) {
1130 tty_wakeup(tty);
1131 tty_kref_put(tty);
1132 }
1133 gsm_control_reply(gsm, CMD_MSC, data, clen);
1134}
1135
1136/**
1137 * gsm_control_rls - remote line status
1138 * @gsm: GSM channel
1139 * @data: data bytes
1140 * @clen: data length
1141 *
1142 * The modem sends us a two byte message on the control channel whenever
1143 * it wishes to send us an error state from the virtual link. Stuff
1144 * this into the uplink tty if present
1145 */
1146
4feb7a4a 1147static void gsm_control_rls(struct gsm_mux *gsm, const u8 *data, int clen)
e1eaea46 1148{
92a19f9c 1149 struct tty_port *port;
f3c909b4 1150 unsigned int addr = 0;
e1eaea46
AC		 1151 u8 bits;
1152 int len = clen;
4feb7a4a 1153 const u8 *dp = data;
e1eaea46
AC		 1154
1155 while (gsm_read_ea(&addr, *dp++) == 0) {
1156 len--;
1157 if (len == 0)
1158 return;
1159 }
1160 /* Must be at least one byte following ea */
1161 len--;
1162 if (len <= 0)
1163 return;
1164 addr >>= 1;
1165 /* Closed port, or invalid ? */
1166 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1167 return;
1168 /* No error ? */
1169 bits = *dp;
1170 if ((bits & 1) == 0)
1171 return;
e1eaea46 1172
92a19f9c
JS		 1173 port = &gsm->dlci[addr]->port;
1174
1175 if (bits & 2)
1176 tty_insert_flip_char(port, 0, TTY_OVERRUN);
1177 if (bits & 4)
1178 tty_insert_flip_char(port, 0, TTY_PARITY);
1179 if (bits & 8)
1180 tty_insert_flip_char(port, 0, TTY_FRAME);
1181
2e124b4a
JS		 1182 tty_flip_buffer_push(port);
1183
e1eaea46
AC		 1184 gsm_control_reply(gsm, CMD_RLS, data, clen);
1185}
1186
1187static void gsm_dlci_begin_close(struct gsm_dlci *dlci);
0b91b533 1188static void gsm_dlci_close(struct gsm_dlci *dlci);
e1eaea46
AC		 1189
1190/**
1191 * gsm_control_message - DLCI 0 control processing
1192 * @gsm: our GSM mux
1193 * @command: the command EA
1194 * @data: data beyond the command/length EAs
1195 * @clen: length
1196 *
1197 * Input processor for control messages from the other end of the link.
1198 * Processes the incoming request and queues a response frame or an
1199 * NSC response if not supported
1200 */
1201
1202static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
4feb7a4a 1203 const u8 *data, int clen)
e1eaea46
AC		 1204{
1205 u8 buf[1];
5e44708f 1206 unsigned long flags;
0b91b533
ZZ		 1207 struct gsm_dlci *dlci;
1208 int i;
1209 int address;
5e44708f 1210
e1eaea46
AC		 1211 switch (command) {
1212 case CMD_CLD: {
0b91b533
ZZ		 1213 if (addr_cnt > 0) {
1214 for (i = 0; i < addr_cnt; i++) {
1215 address = addr_open[i];
1216 dlci = gsm->dlci[address];
1217 gsm_dlci_close(dlci);
1218 addr_open[i] = 0;
1219 }
1220 }
e1eaea46 1221 /* Modem wishes to close down */
0b91b533 1222 dlci = gsm->dlci[0];
e1eaea46 1223 if (dlci) {
5677fcf3
JS		 1224 dlci->dead = true;
1225 gsm->dead = true;
0b91b533
ZZ		 1226 gsm_dlci_close(dlci);
1227 addr_cnt = 0;
1228 gsm_response(gsm, 0, UA|PF);
e1eaea46
AC		 1229 }
1230 }
1231 break;
1232 case CMD_TEST:
1233 /* Modem wishes to test, reply with the data */
1234 gsm_control_reply(gsm, CMD_TEST, data, clen);
1235 break;
1236 case CMD_FCON:
e1eaea46 1237 /* Modem can accept data again */
7a9ed9c0 1238 gsm->constipated = false;
c01af4fe 1239 gsm_control_reply(gsm, CMD_FCON, NULL, 0);
e1eaea46 1240 /* Kick the link in case it is idling */
5e44708f 1241 spin_lock_irqsave(&gsm->tx_lock, flags);
01dbb362 1242 gsm_data_kick(gsm, NULL);
5e44708f 1243 spin_unlock_irqrestore(&gsm->tx_lock, flags);
e1eaea46 1244 break;
c01af4fe
FB		 1245 case CMD_FCOFF:
1246 /* Modem wants us to STFU */
7a9ed9c0 1247 gsm->constipated = true;
c01af4fe
FB		 1248 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0);
1249 break;
e1eaea46
AC		 1250 case CMD_MSC:
1251 /* Out of band modem line change indicator for a DLCI */
1252 gsm_control_modem(gsm, data, clen);
1253 break;
1254 case CMD_RLS:
1255 /* Out of band error reception for a DLCI */
1256 gsm_control_rls(gsm, data, clen);
1257 break;
1258 case CMD_PSC:
1259 /* Modem wishes to enter power saving state */
1260 gsm_control_reply(gsm, CMD_PSC, NULL, 0);
1261 break;
1262 /* Optional unsupported commands */
1263 case CMD_PN: /* Parameter negotiation */
25985edc
LDM		 1264 case CMD_RPN: /* Remote port negotiation */
1265 case CMD_SNC: /* Service negotiation command */
e1eaea46
AC		 1266 default:
1267 /* Reply to bad commands with an NSC */
1268 buf[0] = command;
1269 gsm_control_reply(gsm, CMD_NSC, buf, 1);
1270 break;
1271 }
1272}
1273
1274/**
1275 * gsm_control_response - process a response to our control
1276 * @gsm: our GSM mux
1277 * @command: the command (response) EA
1278 * @data: data beyond the command/length EA
1279 * @clen: length
1280 *
1281 * Process a response to an outstanding command. We only allow a single
1282 * control message in flight so this is fairly easy. All the clean up
1283 * is done by the caller, we just update the fields, flag it as done
1284 * and return
1285 */
1286
1287static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
4feb7a4a 1288 const u8 *data, int clen)
e1eaea46
AC		 1289{
1290 struct gsm_control *ctrl;
1291 unsigned long flags;
1292
1293 spin_lock_irqsave(&gsm->control_lock, flags);
1294
1295 ctrl = gsm->pending_cmd;
1296 /* Does the reply match our command */
1297 command |= 1;
1298 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) {
1299 /* Our command was replied to, kill the retry timer */
1300 del_timer(&gsm->t2_timer);
1301 gsm->pending_cmd = NULL;
1302 /* Rejected by the other end */
1303 if (command == CMD_NSC)
1304 ctrl->error = -EOPNOTSUPP;
1305 ctrl->done = 1;
1306 wake_up(&gsm->event);
1307 }
1308 spin_unlock_irqrestore(&gsm->control_lock, flags);
1309}
1310
1311/**
5f9a31d6 1312 * gsm_control_transmit - send control packet
e1eaea46
AC		 1313 * @gsm: gsm mux
1314 * @ctrl: frame to send
1315 *
1316 * Send out a pending control command (called under control lock)
1317 */
1318
1319static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl)
1320{
ed43b47b 1321 struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, gsm->ftype);
e1eaea46
AC		 1322 if (msg == NULL)
1323 return;
1324 msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */
1325 memcpy(msg->data + 1, ctrl->data, ctrl->len);
1326 gsm_data_queue(gsm->dlci[0], msg);
1327}
1328
1329/**
1330 * gsm_control_retransmit - retransmit a control frame
724ac070 1331 * @t: timer contained in our gsm object
e1eaea46
AC		 1332 *
1333 * Called off the T2 timer expiry in order to retransmit control frames
1334 * that have been lost in the system somewhere. The control_lock protects
1335 * us from colliding with another sender or a receive completion event.
1336 * In that situation the timer may still occur in a small window but
1337 * gsm->pending_cmd will be NULL and we just let the timer expire.
1338 */
1339
e99e88a9 1340static void gsm_control_retransmit(struct timer_list *t)
e1eaea46 1341{
e99e88a9 1342 struct gsm_mux *gsm = from_timer(gsm, t, t2_timer);
e1eaea46
AC		 1343 struct gsm_control *ctrl;
1344 unsigned long flags;
1345 spin_lock_irqsave(&gsm->control_lock, flags);
1346 ctrl = gsm->pending_cmd;
1347 if (ctrl) {
1348 gsm->cretries--;
1349 if (gsm->cretries == 0) {
1350 gsm->pending_cmd = NULL;
1351 ctrl->error = -ETIMEDOUT;
1352 ctrl->done = 1;
1353 spin_unlock_irqrestore(&gsm->control_lock, flags);
1354 wake_up(&gsm->event);
1355 return;
1356 }
1357 gsm_control_transmit(gsm, ctrl);
1358 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1359 }
1360 spin_unlock_irqrestore(&gsm->control_lock, flags);
1361}
1362
1363/**
1364 * gsm_control_send - send a control frame on DLCI 0
1365 * @gsm: the GSM channel
1366 * @command: command to send including CR bit
1367 * @data: bytes of data (must be kmalloced)
724ac070 1368 * @clen: length of the block to send
e1eaea46
AC		 1369 *
1370 * Queue and dispatch a control command. Only one command can be
1371 * active at a time. In theory more can be outstanding but the matching
1372 * gets really complicated so for now stick to one outstanding.
1373 */
1374
1375static struct gsm_control *gsm_control_send(struct gsm_mux *gsm,
1376 unsigned int command, u8 *data, int clen)
1377{
1378 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control),
1379 GFP_KERNEL);
1380 unsigned long flags;
1381 if (ctrl == NULL)
1382 return NULL;
1383retry:
1384 wait_event(gsm->event, gsm->pending_cmd == NULL);
1385 spin_lock_irqsave(&gsm->control_lock, flags);
1386 if (gsm->pending_cmd != NULL) {
1387 spin_unlock_irqrestore(&gsm->control_lock, flags);
1388 goto retry;
1389 }
1390 ctrl->cmd = command;
1391 ctrl->data = data;
1392 ctrl->len = clen;
1393 gsm->pending_cmd = ctrl;
e9ec2254
TL		 1394
1395 /* If DLCI0 is in ADM mode skip retries, it won't respond */
1396 if (gsm->dlci[0]->mode == DLCI_MODE_ADM)
1397 gsm->cretries = 1;
1398 else
1399 gsm->cretries = gsm->n2;
1400
e1eaea46
AC		 1401 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1402 gsm_control_transmit(gsm, ctrl);
1403 spin_unlock_irqrestore(&gsm->control_lock, flags);
1404 return ctrl;
1405}
1406
1407/**
1408 * gsm_control_wait - wait for a control to finish
1409 * @gsm: GSM mux
1410 * @control: control we are waiting on
1411 *
1412 * Waits for the control to complete or time out. Frees any used
1413 * resources and returns 0 for success, or an error if the remote
1414 * rejected or ignored the request.
1415 */
1416
1417static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
1418{
1419 int err;
1420 wait_event(gsm->event, control->done == 1);
1421 err = control->error;
1422 kfree(control);
1423 return err;
1424}
1425
1426
1427/*
1428 * DLCI level handling: Needs krefs
1429 */
1430
1431/*
1432 * State transitions and timers
1433 */
1434
1435/**
1436 * gsm_dlci_close - a DLCI has closed
1437 * @dlci: DLCI that closed
1438 *
1439 * Perform processing when moving a DLCI into closed state. If there
1440 * is an attached tty this is hung up
1441 */
1442
1443static void gsm_dlci_close(struct gsm_dlci *dlci)
1444{
1445 del_timer(&dlci->t1);
1446 if (debug & 8)
5f9a31d6 1447 pr_debug("DLCI %d goes closed.\n", dlci->addr);
e1eaea46
AC		 1448 dlci->state = DLCI_CLOSED;
1449 if (dlci->addr != 0) {
aa27a094 1450 tty_port_tty_hangup(&dlci->port, false);
036bca1f 1451 kfifo_reset(&dlci->fifo);
e1eaea46 1452 } else
5677fcf3 1453 dlci->gsm->dead = true;
5b87686e
ZZ		 1454 /* Unregister gsmtty driver,report gsmtty dev remove uevent for user */
1455 tty_unregister_device(gsm_tty_driver, dlci->addr);
e1eaea46
AC		 1456 wake_up(&dlci->gsm->event);
1457 /* A DLCI 0 close is a MUX termination so we need to kick that
1458 back to userspace somehow */
1459}
1460
1461/**
1462 * gsm_dlci_open - a DLCI has opened
1463 * @dlci: DLCI that opened
1464 *
1465 * Perform processing when moving a DLCI into open state.
1466 */
1467
1468static void gsm_dlci_open(struct gsm_dlci *dlci)
1469{
1470 /* Note that SABM UA .. SABM UA first UA lost can mean that we go
1471 open -> open */
1472 del_timer(&dlci->t1);
1473 /* This will let a tty open continue */
1474 dlci->state = DLCI_OPEN;
1475 if (debug & 8)
5f9a31d6 1476 pr_debug("DLCI %d goes open.\n", dlci->addr);
5b87686e
ZZ		 1477 /* Register gsmtty driver,report gsmtty dev add uevent for user */
1478 tty_register_device(gsm_tty_driver, dlci->addr, NULL);
e1eaea46
AC		 1479 wake_up(&dlci->gsm->event);
1480}
1481
1482/**
1483 * gsm_dlci_t1 - T1 timer expiry
724ac070 1484 * @t: timer contained in the DLCI that opened
e1eaea46
AC		 1485 *
1486 * The T1 timer handles retransmits of control frames (essentially of
1487 * SABM and DISC). We resend the command until the retry count runs out
1488 * in which case an opening port goes back to closed and a closing port
1489 * is simply put into closed state (any further frames from the other
1490 * end will get a DM response)
ea3d8465
TL		 1491 *
1492 * Some control dlci can stay in ADM mode with other dlci working just
1493 * fine. In that case we can just keep the control dlci open after the
1494 * DLCI_OPENING retries time out.
e1eaea46
AC		 1495 */
1496
e99e88a9 1497static void gsm_dlci_t1(struct timer_list *t)
e1eaea46 1498{
e99e88a9 1499 struct gsm_dlci *dlci = from_timer(dlci, t, t1);
e1eaea46
AC		 1500 struct gsm_mux *gsm = dlci->gsm;
1501
1502 switch (dlci->state) {
1503 case DLCI_OPENING:
1504 dlci->retries--;
1505 if (dlci->retries) {
1506 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1507 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
ea3d8465
TL		 1508 } else if (!dlci->addr && gsm->control == (DM | PF)) {
1509 if (debug & 8)
1510 pr_info("DLCI %d opening in ADM mode.\n",
1511 dlci->addr);
e9ec2254 1512 dlci->mode = DLCI_MODE_ADM;
ea3d8465
TL		 1513 gsm_dlci_open(dlci);
1514 } else {
e1eaea46 1515 gsm_dlci_close(dlci);
ea3d8465
TL		 1516 }
1517
e1eaea46
AC		 1518 break;
1519 case DLCI_CLOSING:
1520 dlci->retries--;
1521 if (dlci->retries) {
1522 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1523 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1524 } else
1525 gsm_dlci_close(dlci);
1526 break;
72ae8cc1
JS		 1527 default:
1528 pr_debug("%s: unhandled state: %d\n", __func__, dlci->state);
1529 break;
e1eaea46
AC		 1530 }
1531}
1532
1533/**
1534 * gsm_dlci_begin_open - start channel open procedure
1535 * @dlci: DLCI to open
1536 *
1537 * Commence opening a DLCI from the Linux side. We issue SABM messages
ea3d8465
TL		 1538 * to the modem which should then reply with a UA or ADM, at which point
1539 * we will move into open state. Opening is done asynchronously with retry
e1eaea46
AC		 1540 * running off timers and the responses.
1541 */
1542
1543static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
1544{
1545 struct gsm_mux *gsm = dlci->gsm;
1546 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING)
1547 return;
1548 dlci->retries = gsm->n2;
1549 dlci->state = DLCI_OPENING;
1550 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1551 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1552}
1553
1554/**
1555 * gsm_dlci_begin_close - start channel open procedure
1556 * @dlci: DLCI to open
1557 *
1558 * Commence closing a DLCI from the Linux side. We issue DISC messages
1559 * to the modem which should then reply with a UA, at which point we
1560 * will move into closed state. Closing is done asynchronously with retry
1561 * off timers. We may also receive a DM reply from the other end which
1562 * indicates the channel was already closed.
1563 */
1564
1565static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
1566{
1567 struct gsm_mux *gsm = dlci->gsm;
1568 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
1569 return;
1570 dlci->retries = gsm->n2;
1571 dlci->state = DLCI_CLOSING;
1572 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1573 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1574}
1575
1576/**
1577 * gsm_dlci_data - data arrived
1578 * @dlci: channel
1579 * @data: block of bytes received
724ac070 1580 * @clen: length of received block
e1eaea46
AC		 1581 *
1582 * A UI or UIH frame has arrived which contains data for a channel
1583 * other than the control channel. If the relevant virtual tty is
1584 * open we shovel the bits down it, if not we drop them.
1585 */
1586
4feb7a4a 1587static void gsm_dlci_data(struct gsm_dlci *dlci, const u8 *data, int clen)
e1eaea46
AC		 1588{
1589 /* krefs .. */
1590 struct tty_port *port = &dlci->port;
2e124b4a 1591 struct tty_struct *tty;
e1eaea46 1592 unsigned int modem = 0;
7263287a 1593 int len = clen;
e1eaea46
AC		 1594
1595 if (debug & 16)
2e124b4a
JS		 1596 pr_debug("%d bytes for tty\n", len);
1597 switch (dlci->adaption) {
1598 /* Unsupported types */
3e913eeb 1599 case 4: /* Packetised interruptible data */
2e124b4a 1600 break;
3e913eeb 1601 case 3: /* Packetised uininterruptible voice/data */
2e124b4a 1602 break;
3e913eeb 1603 case 2: /* Asynchronous serial with line state in each frame */
2e124b4a
JS		 1604 while (gsm_read_ea(&modem, *data++) == 0) {
1605 len--;
1606 if (len == 0)
1607 return;
1608 }
1609 tty = tty_port_tty_get(port);
1610 if (tty) {
7263287a 1611 gsm_process_modem(tty, dlci, modem, clen);
2e124b4a 1612 tty_kref_put(tty);
e1eaea46 1613 }
df561f66 1614 fallthrough;
3e913eeb 1615 case 1: /* Line state will go via DLCI 0 controls only */
2e124b4a
JS		 1616 default:
1617 tty_insert_flip_string(port, data, len);
1618 tty_flip_buffer_push(port);
e1eaea46
AC		 1619 }
1620}
1621
1622/**
542a121a 1623 * gsm_dlci_command - data arrived on control channel
e1eaea46
AC		 1624 * @dlci: channel
1625 * @data: block of bytes received
1626 * @len: length of received block
1627 *
1628 * A UI or UIH frame has arrived which contains data for DLCI 0 the
1629 * control channel. This should contain a command EA followed by
1630 * control data bytes. The command EA contains a command/response bit
1631 * and we divide up the work accordingly.
1632 */
1633
4feb7a4a 1634static void gsm_dlci_command(struct gsm_dlci *dlci, const u8 *data, int len)
e1eaea46
AC		 1635{
1636 /* See what command is involved */
1637 unsigned int command = 0;
1638 while (len-- > 0) {
1639 if (gsm_read_ea(&command, *data++) == 1) {
1640 int clen = *data++;
1641 len--;
1642 /* FIXME: this is properly an EA */
1643 clen >>= 1;
1644 /* Malformed command ? */
1645 if (clen > len)
1646 return;
1647 if (command & 1)
1648 gsm_control_message(dlci->gsm, command,
1649 data, clen);
1650 else
1651 gsm_control_response(dlci->gsm, command,
1652 data, clen);
1653 return;
1654 }
1655 }
1656}
1657
1658/*
1659 * Allocate/Free DLCI channels
1660 */
1661
1662/**
1663 * gsm_dlci_alloc - allocate a DLCI
1664 * @gsm: GSM mux
1665 * @addr: address of the DLCI
1666 *
1667 * Allocate and install a new DLCI object into the GSM mux.
1668 *
1669 * FIXME: review locking races
1670 */
1671
1672static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
1673{
1674 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC);
1675 if (dlci == NULL)
1676 return NULL;
1677 spin_lock_init(&dlci->lock);
bcd5abe2 1678 mutex_init(&dlci->mutex);
036bca1f 1679 if (kfifo_alloc(&dlci->fifo, 4096, GFP_KERNEL) < 0) {
e1eaea46
AC		 1680 kfree(dlci);
1681 return NULL;
1682 }
1683
1684 skb_queue_head_init(&dlci->skb_list);
e99e88a9 1685 timer_setup(&dlci->t1, gsm_dlci_t1, 0);
e1eaea46
AC		 1686 tty_port_init(&dlci->port);
1687 dlci->port.ops = &gsm_port_ops;
1688 dlci->gsm = gsm;
1689 dlci->addr = addr;
1690 dlci->adaption = gsm->adaption;
1691 dlci->state = DLCI_CLOSED;
1692 if (addr)
1693 dlci->data = gsm_dlci_data;
1694 else
1695 dlci->data = gsm_dlci_command;
1696 gsm->dlci[addr] = dlci;
1697 return dlci;
1698}
1699
1700/**
6ab8fba7 1701 * gsm_dlci_free - free DLCI
724ac070 1702 * @port: tty port for DLCI to free
6ab8fba7
RG		 1703 *
1704 * Free up a DLCI.
1705 *
1706 * Can sleep.
1707 */
9a8e62bc 1708static void gsm_dlci_free(struct tty_port *port)
6ab8fba7 1709{
9a8e62bc 1710 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
6ab8fba7
RG		 1711
1712 del_timer_sync(&dlci->t1);
1713 dlci->gsm->dlci[dlci->addr] = NULL;
036bca1f 1714 kfifo_free(&dlci->fifo);
6ab8fba7 1715 while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
329e5678 1716 dev_kfree_skb(dlci->skb);
6ab8fba7
RG		 1717 kfree(dlci);
1718}
1719
1720static inline void dlci_get(struct gsm_dlci *dlci)
1721{
9a8e62bc 1722 tty_port_get(&dlci->port);
6ab8fba7
RG		 1723}
1724
1725static inline void dlci_put(struct gsm_dlci *dlci)
1726{
9a8e62bc 1727 tty_port_put(&dlci->port);
6ab8fba7
RG		 1728}
1729
4d9b1090
DB		 1730static void gsm_destroy_network(struct gsm_dlci *dlci);
1731
6ab8fba7
RG		 1732/**
1733 * gsm_dlci_release - release DLCI
e1eaea46
AC		 1734 * @dlci: DLCI to destroy
1735 *
6ab8fba7
RG		 1736 * Release a DLCI. Actual free is deferred until either
1737 * mux is closed or tty is closed - whichever is last.
e1eaea46
AC		 1738 *
1739 * Can sleep.
1740 */
6ab8fba7 1741static void gsm_dlci_release(struct gsm_dlci *dlci)
e1eaea46
AC		 1742{
1743 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1744 if (tty) {
4d9b1090
DB		 1745 mutex_lock(&dlci->mutex);
1746 gsm_destroy_network(dlci);
1747 mutex_unlock(&dlci->mutex);
1748
7030082a 1749 tty_hangup(tty);
be706572 1750
4d9b1090 1751 tty_port_tty_set(&dlci->port, NULL);
e1eaea46
AC		 1752 tty_kref_put(tty);
1753 }
4d9b1090 1754 dlci->state = DLCI_CLOSED;
6ab8fba7 1755 dlci_put(dlci);
e1eaea46
AC		 1756}
1757
e1eaea46
AC		 1758/*
1759 * LAPBish link layer logic
1760 */
1761
1762/**
1763 * gsm_queue - a GSM frame is ready to process
1764 * @gsm: pointer to our gsm mux
1765 *
1766 * At this point in time a frame has arrived and been demangled from
1767 * the line encoding. All the differences between the encodings have
1768 * been handled below us and the frame is unpacked into the structures.
1769 * The fcs holds the header FCS but any data FCS must be added here.
1770 */
1771
1772static void gsm_queue(struct gsm_mux *gsm)
1773{
1774 struct gsm_dlci *dlci;
1775 u8 cr;
1776 int address;
0b91b533 1777 int i, j, k, address_tmp;
e1eaea46
AC		 1778 /* We have to sneak a look at the packet body to do the FCS.
1779 A somewhat layering violation in the spec */
1780
1781 if ((gsm->control & ~PF) == UI)
1782 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len);
f3c909b4
AI		 1783 if (gsm->encoding == 0) {
1784 /* WARNING: gsm->received_fcs is used for
1785 gsm->encoding = 0 only.
1786 In this case it contain the last piece of data
1787 required to generate final CRC */
9db4e438
MK		 1788 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs);
1789 }
e1eaea46
AC		 1790 if (gsm->fcs != GOOD_FCS) {
1791 gsm->bad_fcs++;
1792 if (debug & 4)
5f9a31d6 1793 pr_debug("BAD FCS %02x\n", gsm->fcs);
e1eaea46
AC		 1794 return;
1795 }
1796 address = gsm->address >> 1;
1797 if (address >= NUM_DLCI)
1798 goto invalid;
1799
1800 cr = gsm->address & 1; /* C/R bit */
1801
1802 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
1803
1804 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */
1805 dlci = gsm->dlci[address];
1806
1807 switch (gsm->control) {
1808 case SABM|PF:
cd936621 1809 if (cr == 1)
e1eaea46
AC		 1810 goto invalid;
1811 if (dlci == NULL)
1812 dlci = gsm_dlci_alloc(gsm, address);
1813 if (dlci == NULL)
1814 return;
1815 if (dlci->dead)
cc0f4212 1816 gsm_response(gsm, address, DM|PF);
e1eaea46 1817 else {
cc0f4212 1818 gsm_response(gsm, address, UA|PF);
e1eaea46 1819 gsm_dlci_open(dlci);
0b91b533
ZZ		 1820 /* Save dlci open address */
1821 if (address) {
1822 addr_open[addr_cnt] = address;
1823 addr_cnt++;
1824 }
e1eaea46
AC		 1825 }
1826 break;
1827 case DISC|PF:
cd936621 1828 if (cr == 1)
e1eaea46
AC		 1829 goto invalid;
1830 if (dlci == NULL || dlci->state == DLCI_CLOSED) {
cc0f4212 1831 gsm_response(gsm, address, DM|PF);
e1eaea46
AC		 1832 return;
1833 }
1834 /* Real close complete */
0b91b533
ZZ		 1835 if (!address) {
1836 if (addr_cnt > 0) {
1837 for (i = 0; i < addr_cnt; i++) {
1838 address = addr_open[i];
1839 dlci = gsm->dlci[address];
1840 gsm_dlci_close(dlci);
1841 addr_open[i] = 0;
1842 }
1843 }
1844 dlci = gsm->dlci[0];
1845 gsm_dlci_close(dlci);
1846 addr_cnt = 0;
1847 gsm_response(gsm, 0, UA|PF);
1848 } else {
1849 gsm_response(gsm, address, UA|PF);
1850 gsm_dlci_close(dlci);
1851 /* clear dlci address */
1852 for (j = 0; j < addr_cnt; j++) {
1853 address_tmp = addr_open[j];
1854 if (address_tmp == address) {
1855 for (k = j; k < addr_cnt; k++)
1856 addr_open[k] = addr_open[k+1];
46292622
DC		 1857 addr_cnt--;
1858 break;
0b91b533
ZZ		 1859 }
1860 }
1861 }
e1eaea46
AC		 1862 break;
1863 case UA:
1864 case UA|PF:
1865 if (cr == 0 || dlci == NULL)
1866 break;
1867 switch (dlci->state) {
1868 case DLCI_CLOSING:
1869 gsm_dlci_close(dlci);
1870 break;
1871 case DLCI_OPENING:
1872 gsm_dlci_open(dlci);
1873 break;
72ae8cc1
JS		 1874 default:
1875 pr_debug("%s: unhandled state: %d\n", __func__,
1876 dlci->state);
1877 break;
e1eaea46
AC		 1878 }
1879 break;
1880 case DM: /* DM can be valid unsolicited */
1881 case DM|PF:
1882 if (cr)
1883 goto invalid;
1884 if (dlci == NULL)
1885 return;
1886 gsm_dlci_close(dlci);
1887 break;
1888 case UI:
1889 case UI|PF:
1890 case UIH:
1891 case UIH|PF:
1892#if 0
1893 if (cr)
1894 goto invalid;
1895#endif
1896 if (dlci == NULL || dlci->state != DLCI_OPEN) {
1897 gsm_command(gsm, address, DM|PF);
1898 return;
1899 }
1900 dlci->data(dlci, gsm->buf, gsm->len);
1901 break;
1902 default:
1903 goto invalid;
1904 }
1905 return;
1906invalid:
1907 gsm->malformed++;
1908 return;
1909}
1910
1911
1912/**
1913 * gsm0_receive - perform processing for non-transparency
1914 * @gsm: gsm data for this ldisc instance
1915 * @c: character
1916 *
1917 * Receive bytes in gsm mode 0
1918 */
1919
1920static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
1921{
c2f2f000
AC		 1922 unsigned int len;
1923
e1eaea46
AC		 1924 switch (gsm->state) {
1925 case GSM_SEARCH: /* SOF marker */
1926 if (c == GSM0_SOF) {
1927 gsm->state = GSM_ADDRESS;
1928 gsm->address = 0;
1929 gsm->len = 0;
1930 gsm->fcs = INIT_FCS;
1931 }
c2f2f000
AC		 1932 break;
1933 case GSM_ADDRESS: /* Address EA */
e1eaea46
AC		 1934 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1935 if (gsm_read_ea(&gsm->address, c))
1936 gsm->state = GSM_CONTROL;
1937 break;
1938 case GSM_CONTROL: /* Control Byte */
1939 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1940 gsm->control = c;
c2f2f000 1941 gsm->state = GSM_LEN0;
e1eaea46 1942 break;
c2f2f000 1943 case GSM_LEN0: /* Length EA */
e1eaea46
AC		 1944 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1945 if (gsm_read_ea(&gsm->len, c)) {
1946 if (gsm->len > gsm->mru) {
1947 gsm->bad_size++;
1948 gsm->state = GSM_SEARCH;
1949 break;
1950 }
1951 gsm->count = 0;
c2f2f000
AC		 1952 if (!gsm->len)
1953 gsm->state = GSM_FCS;
1954 else
1955 gsm->state = GSM_DATA;
1956 break;
e1eaea46 1957 }
c2f2f000
AC		 1958 gsm->state = GSM_LEN1;
1959 break;
1960 case GSM_LEN1:
1961 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1962 len = c;
1963 gsm->len |= len << 7;
1964 if (gsm->len > gsm->mru) {
1965 gsm->bad_size++;
1966 gsm->state = GSM_SEARCH;
1967 break;
e1eaea46 1968 }
c2f2f000
AC		 1969 gsm->count = 0;
1970 if (!gsm->len)
1971 gsm->state = GSM_FCS;
1972 else
1973 gsm->state = GSM_DATA;
e1eaea46
AC		 1974 break;
1975 case GSM_DATA: /* Data */
1976 gsm->buf[gsm->count++] = c;
1977 if (gsm->count == gsm->len)
1978 gsm->state = GSM_FCS;
1979 break;
1980 case GSM_FCS: /* FCS follows the packet */
c2f2f000 1981 gsm->received_fcs = c;
e1eaea46 1982 gsm_queue(gsm);
c2f2f000
AC		 1983 gsm->state = GSM_SSOF;
1984 break;
1985 case GSM_SSOF:
1986 if (c == GSM0_SOF) {
1987 gsm->state = GSM_SEARCH;
1988 break;
1989 }
e1eaea46 1990 break;
329aa6e6
JS		 1991 default:
1992 pr_debug("%s: unhandled state: %d\n", __func__, gsm->state);
1993 break;
e1eaea46
AC		 1994 }
1995}
1996
1997/**
c2f2f000 1998 * gsm1_receive - perform processing for non-transparency
e1eaea46
AC		 1999 * @gsm: gsm data for this ldisc instance
2000 * @c: character
2001 *
2002 * Receive bytes in mode 1 (Advanced option)
2003 */
2004
2005static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
2006{
2007 if (c == GSM1_SOF) {
2008 /* EOF is only valid in frame if we have got to the data state
2009 and received at least one byte (the FCS) */
2010 if (gsm->state == GSM_DATA && gsm->count) {
2011 /* Extract the FCS */
2012 gsm->count--;
2013 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
2014 gsm->len = gsm->count;
2015 gsm_queue(gsm);
2016 gsm->state = GSM_START;
2017 return;
2018 }
2019 /* Any partial frame was a runt so go back to start */
2020 if (gsm->state != GSM_START) {
2021 gsm->malformed++;
2022 gsm->state = GSM_START;
2023 }
2024 /* A SOF in GSM_START means we are still reading idling or
2025 framing bytes */
2026 return;
2027 }
2028
2029 if (c == GSM1_ESCAPE) {
c50704bd 2030 gsm->escape = true;
e1eaea46
AC		 2031 return;
2032 }
2033
2034 /* Only an unescaped SOF gets us out of GSM search */
2035 if (gsm->state == GSM_SEARCH)
2036 return;
2037
2038 if (gsm->escape) {
2039 c ^= GSM1_ESCAPE_BITS;
c50704bd 2040 gsm->escape = false;
e1eaea46
AC		 2041 }
2042 switch (gsm->state) {
2043 case GSM_START: /* First byte after SOF */
2044 gsm->address = 0;
2045 gsm->state = GSM_ADDRESS;
2046 gsm->fcs = INIT_FCS;
df561f66 2047 fallthrough;
e1eaea46
AC		 2048 case GSM_ADDRESS: /* Address continuation */
2049 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2050 if (gsm_read_ea(&gsm->address, c))
2051 gsm->state = GSM_CONTROL;
2052 break;
2053 case GSM_CONTROL: /* Control Byte */
2054 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2055 gsm->control = c;
2056 gsm->count = 0;
2057 gsm->state = GSM_DATA;
2058 break;
2059 case GSM_DATA: /* Data */
5f9a31d6 2060 if (gsm->count > gsm->mru) { /* Allow one for the FCS */
e1eaea46
AC		 2061 gsm->state = GSM_OVERRUN;
2062 gsm->bad_size++;
2063 } else
2064 gsm->buf[gsm->count++] = c;
2065 break;
2066 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */
2067 break;
329aa6e6
JS		 2068 default:
2069 pr_debug("%s: unhandled state: %d\n", __func__, gsm->state);
2070 break;
e1eaea46
AC		 2071 }
2072}
2073
2074/**
2075 * gsm_error - handle tty error
2076 * @gsm: ldisc data
2077 * @data: byte received (may be invalid)
2078 * @flag: error received
2079 *
2080 * Handle an error in the receipt of data for a frame. Currently we just
2081 * go back to hunting for a SOF.
2082 *
2083 * FIXME: better diagnostics ?
2084 */
2085
2086static void gsm_error(struct gsm_mux *gsm,
2087 unsigned char data, unsigned char flag)
2088{
2089 gsm->state = GSM_SEARCH;
2090 gsm->io_error++;
2091}
2092
71e07791
SH		 2093static int gsm_disconnect(struct gsm_mux *gsm)
2094{
2095 struct gsm_dlci *dlci = gsm->dlci[0];
2096 struct gsm_control *gc;
2097
2098 if (!dlci)
2099 return 0;
2100
2101 /* In theory disconnecting DLCI 0 is sufficient but for some
2102 modems this is apparently not the case. */
2103 gc = gsm_control_send(gsm, CMD_CLD, NULL, 0);
2104 if (gc)
2105 gsm_control_wait(gsm, gc);
2106
2107 del_timer_sync(&gsm->t2_timer);
2108 /* Now we are sure T2 has stopped */
2109
2110 gsm_dlci_begin_close(dlci);
2111 wait_event_interruptible(gsm->event,
2112 dlci->state == DLCI_CLOSED);
2113
2114 if (signal_pending(current))
2115 return -EINTR;
2116
2117 return 0;
2118}
2119
e1eaea46
AC		 2120/**
2121 * gsm_cleanup_mux - generic GSM protocol cleanup
2122 * @gsm: our mux
2123 *
2124 * Clean up the bits of the mux which are the same for all framing
2125 * protocols. Remove the mux from the mux table, stop all the timers
2126 * and then shut down each device hanging up the channels as we go.
2127 */
2128
54af5836 2129static void gsm_cleanup_mux(struct gsm_mux *gsm)
e1eaea46
AC		 2130{
2131 int i;
2132 struct gsm_dlci *dlci = gsm->dlci[0];
329e5678 2133 struct gsm_msg *txq, *ntxq;
e1eaea46 2134
5677fcf3 2135 gsm->dead = true;
e1eaea46
AC		 2136
2137 spin_lock(&gsm_mux_lock);
2138 for (i = 0; i < MAX_MUX; i++) {
2139 if (gsm_mux[i] == gsm) {
2140 gsm_mux[i] = NULL;
2141 break;
2142 }
2143 }
2144 spin_unlock(&gsm_mux_lock);
d175feca
JS		 2145 /* open failed before registering => nothing to do */
2146 if (i == MAX_MUX)
2147 return;
e1eaea46
AC		 2148
2149 del_timer_sync(&gsm->t2_timer);
2150 /* Now we are sure T2 has stopped */
71e07791 2151 if (dlci)
5677fcf3 2152 dlci->dead = true;
71e07791 2153
e1eaea46 2154 /* Free up any link layer users */
dfabf7ff 2155 mutex_lock(&gsm->mutex);
e1eaea46
AC		 2156 for (i = 0; i < NUM_DLCI; i++)
2157 if (gsm->dlci[i])
6ab8fba7 2158 gsm_dlci_release(gsm->dlci[i]);
dfabf7ff 2159 mutex_unlock(&gsm->mutex);
e1eaea46 2160 /* Now wipe the queues */
b4338e1e 2161 list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list)
e1eaea46 2162 kfree(txq);
b4338e1e 2163 INIT_LIST_HEAD(&gsm->tx_list);
e1eaea46 2164}
e1eaea46
AC		 2165
2166/**
2167 * gsm_activate_mux - generic GSM setup
2168 * @gsm: our mux
2169 *
2170 * Set up the bits of the mux which are the same for all framing
2171 * protocols. Add the mux to the mux table so it can be opened and
2172 * finally kick off connecting to DLCI 0 on the modem.
2173 */
2174
54af5836 2175static int gsm_activate_mux(struct gsm_mux *gsm)
e1eaea46
AC		 2176{
2177 struct gsm_dlci *dlci;
2178 int i = 0;
2179
e99e88a9 2180 timer_setup(&gsm->t2_timer, gsm_control_retransmit, 0);
e1eaea46
AC		 2181 init_waitqueue_head(&gsm->event);
2182 spin_lock_init(&gsm->control_lock);
2183 spin_lock_init(&gsm->tx_lock);
2184
2185 if (gsm->encoding == 0)
2186 gsm->receive = gsm0_receive;
2187 else
2188 gsm->receive = gsm1_receive;
e1eaea46
AC		 2189
2190 spin_lock(&gsm_mux_lock);
2191 for (i = 0; i < MAX_MUX; i++) {
2192 if (gsm_mux[i] == NULL) {
d50f6dca 2193 gsm->num = i;
e1eaea46
AC		 2194 gsm_mux[i] = gsm;
2195 break;
2196 }
2197 }
2198 spin_unlock(&gsm_mux_lock);
2199 if (i == MAX_MUX)
2200 return -EBUSY;
2201
2202 dlci = gsm_dlci_alloc(gsm, 0);
2203 if (dlci == NULL)
2204 return -ENOMEM;
5677fcf3 2205 gsm->dead = false; /* Tty opens are now permissible */
e1eaea46
AC		 2206 return 0;
2207}
e1eaea46
AC		 2208
2209/**
2210 * gsm_free_mux - free up a mux
724ac070 2211 * @gsm: mux to free
e1eaea46 2212 *
6ab8fba7 2213 * Dispose of allocated resources for a dead mux
e1eaea46 2214 */
54af5836 2215static void gsm_free_mux(struct gsm_mux *gsm)
e1eaea46
AC		 2216{
2217 kfree(gsm->txframe);
2218 kfree(gsm->buf);
2219 kfree(gsm);
2220}
e1eaea46 2221
6ab8fba7
RG		 2222/**
2223 * gsm_free_muxr - free up a mux
724ac070 2224 * @ref: kreference to the mux to free
6ab8fba7
RG		 2225 *
2226 * Dispose of allocated resources for a dead mux
2227 */
2228static void gsm_free_muxr(struct kref *ref)
2229{
2230 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref);
2231 gsm_free_mux(gsm);
2232}
2233
2234static inline void mux_get(struct gsm_mux *gsm)
2235{
2236 kref_get(&gsm->ref);
2237}
2238
2239static inline void mux_put(struct gsm_mux *gsm)
2240{
2241 kref_put(&gsm->ref, gsm_free_muxr);
2242}
2243
43a9e710
MH		 2244static inline unsigned int mux_num_to_base(struct gsm_mux *gsm)
2245{
2246 return gsm->num * NUM_DLCI;
2247}
2248
2249static inline unsigned int mux_line_to_num(unsigned int line)
2250{
2251 return line / NUM_DLCI;
2252}
2253
e1eaea46
AC		 2254/**
2255 * gsm_alloc_mux - allocate a mux
2256 *
2257 * Creates a new mux ready for activation.
2258 */
2259
54af5836 2260static struct gsm_mux *gsm_alloc_mux(void)
e1eaea46
AC		 2261{
2262 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
2263 if (gsm == NULL)
2264 return NULL;
2265 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL);
2266 if (gsm->buf == NULL) {
2267 kfree(gsm);
2268 return NULL;
2269 }
2270 gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL);
2271 if (gsm->txframe == NULL) {
2272 kfree(gsm->buf);
2273 kfree(gsm);
2274 return NULL;
2275 }
2276 spin_lock_init(&gsm->lock);
dfabf7ff 2277 mutex_init(&gsm->mutex);
6ab8fba7 2278 kref_init(&gsm->ref);
b4338e1e 2279 INIT_LIST_HEAD(&gsm->tx_list);
e1eaea46
AC		 2280
2281 gsm->t1 = T1;
2282 gsm->t2 = T2;
2283 gsm->n2 = N2;
2284 gsm->ftype = UIH;
e1eaea46
AC		 2285 gsm->adaption = 1;
2286 gsm->encoding = 1;
2287 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
2288 gsm->mtu = 64;
5677fcf3 2289 gsm->dead = true; /* Avoid early tty opens */
e1eaea46
AC		 2290
2291 return gsm;
2292}
e1eaea46 2293
33841040
TL		 2294static void gsm_copy_config_values(struct gsm_mux *gsm,
2295 struct gsm_config *c)
2296{
2297 memset(c, 0, sizeof(*c));
2298 c->adaption = gsm->adaption;
2299 c->encapsulation = gsm->encoding;
2300 c->initiator = gsm->initiator;
2301 c->t1 = gsm->t1;
2302 c->t2 = gsm->t2;
2303 c->t3 = 0; /* Not supported */
2304 c->n2 = gsm->n2;
2305 if (gsm->ftype == UIH)
2306 c->i = 1;
2307 else
2308 c->i = 2;
2309 pr_debug("Ftype %d i %d\n", gsm->ftype, c->i);
2310 c->mru = gsm->mru;
2311 c->mtu = gsm->mtu;
2312 c->k = 0;
2313}
2314
2315static int gsm_config(struct gsm_mux *gsm, struct gsm_config *c)
2316{
2317 int need_close = 0;
2318 int need_restart = 0;
2319
2320 /* Stuff we don't support yet - UI or I frame transport, windowing */
2321 if ((c->adaption != 1 && c->adaption != 2) || c->k)
2322 return -EOPNOTSUPP;
2323 /* Check the MRU/MTU range looks sane */
2324 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8)
2325 return -EINVAL;
2326 if (c->n2 < 3)
2327 return -EINVAL;
2328 if (c->encapsulation > 1) /* Basic, advanced, no I */
2329 return -EINVAL;
2330 if (c->initiator > 1)
2331 return -EINVAL;
2332 if (c->i == 0 || c->i > 2) /* UIH and UI only */
2333 return -EINVAL;
2334 /*
2335 * See what is needed for reconfiguration
2336 */
2337
2338 /* Timing fields */
2339 if (c->t1 != 0 && c->t1 != gsm->t1)
2340 need_restart = 1;
2341 if (c->t2 != 0 && c->t2 != gsm->t2)
2342 need_restart = 1;
2343 if (c->encapsulation != gsm->encoding)
2344 need_restart = 1;
2345 if (c->adaption != gsm->adaption)
2346 need_restart = 1;
2347 /* Requires care */
2348 if (c->initiator != gsm->initiator)
2349 need_close = 1;
2350 if (c->mru != gsm->mru)
2351 need_restart = 1;
2352 if (c->mtu != gsm->mtu)
2353 need_restart = 1;
2354
2355 /*
2356 * Close down what is needed, restart and initiate the new
2357 * configuration
2358 */
2359
509067bb 2360 if (gsm->initiator && (need_close || need_restart)) {
33841040
TL		 2361 int ret;
2362
2363 ret = gsm_disconnect(gsm);
2364
2365 if (ret)
2366 return ret;
2367 }
2368 if (need_restart)
2369 gsm_cleanup_mux(gsm);
2370
2371 gsm->initiator = c->initiator;
2372 gsm->mru = c->mru;
2373 gsm->mtu = c->mtu;
2374 gsm->encoding = c->encapsulation;
2375 gsm->adaption = c->adaption;
2376 gsm->n2 = c->n2;
2377
2378 if (c->i == 1)
2379 gsm->ftype = UIH;
2380 else if (c->i == 2)
2381 gsm->ftype = UI;
2382
2383 if (c->t1)
2384 gsm->t1 = c->t1;
2385 if (c->t2)
2386 gsm->t2 = c->t2;
2387
2388 /*
2389 * FIXME: We need to separate activation/deactivation from adding
2390 * and removing from the mux array
2391 */
2392 if (need_restart)
2393 gsm_activate_mux(gsm);
2394 if (gsm->initiator && need_close)
2395 gsm_dlci_begin_open(gsm->dlci[0]);
2396 return 0;
2397}
2398
e1eaea46
AC		 2399/**
2400 * gsmld_output - write to link
2401 * @gsm: our mux
2402 * @data: bytes to output
2403 * @len: size
2404 *
2405 * Write a block of data from the GSM mux to the data channel. This
2406 * will eventually be serialized from above but at the moment isn't.
2407 */
2408
2409static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
2410{
2411 if (tty_write_room(gsm->tty) < len) {
2412 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
2413 return -ENOSPC;
2414 }
0a77c4f9
JP		 2415 if (debug & 4)
2416 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET,
2417 data, len);
9136c683 2418 return gsm->tty->ops->write(gsm->tty, data, len);
e1eaea46
AC		 2419}
2420
2421/**
2422 * gsmld_attach_gsm - mode set up
2423 * @tty: our tty structure
2424 * @gsm: our mux
2425 *
2426 * Set up the MUX for basic mode and commence connecting to the
2427 * modem. Currently called from the line discipline set up but
2428 * will need moving to an ioctl path.
2429 */
2430
2431static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2432{
43a9e710
MH		 2433 unsigned int base;
2434 int ret, i;
e1eaea46
AC		 2435
2436 gsm->tty = tty_kref_get(tty);
e1eaea46
AC		 2437 ret = gsm_activate_mux(gsm);
2438 if (ret != 0)
2439 tty_kref_put(gsm->tty);
d50f6dca
RG		 2440 else {
2441 /* Don't register device 0 - this is the control channel and not
2442 a usable tty interface */
5b87686e
ZZ		 2443 if (gsm->initiator) {
2444 base = mux_num_to_base(gsm); /* Base for this MUX */
2445 for (i = 1; i < NUM_DLCI; i++) {
2446 struct device *dev;
0a360e8b 2447
5b87686e 2448 dev = tty_register_device(gsm_tty_driver,
0a360e8b 2449 base + i, NULL);
5b87686e
ZZ		 2450 if (IS_ERR(dev)) {
2451 for (i--; i >= 1; i--)
2452 tty_unregister_device(gsm_tty_driver,
2453 base + i);
2454 return PTR_ERR(dev);
2455 }
0a360e8b
HD		 2456 }
2457 }
d50f6dca 2458 }
e1eaea46
AC		 2459 return ret;
2460}
2461
2462
2463/**
2464 * gsmld_detach_gsm - stop doing 0710 mux
70f23fd6 2465 * @tty: tty attached to the mux
e1eaea46
AC		 2466 * @gsm: mux
2467 *
2468 * Shutdown and then clean up the resources used by the line discipline
2469 */
2470
2471static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2472{
43a9e710 2473 unsigned int base = mux_num_to_base(gsm); /* Base for this MUX */
d50f6dca 2474 int i;
d50f6dca 2475
e1eaea46 2476 WARN_ON(tty != gsm->tty);
5b87686e
ZZ		 2477 if (gsm->initiator) {
2478 for (i = 1; i < NUM_DLCI; i++)
2479 tty_unregister_device(gsm_tty_driver, base + i);
2480 }
e1eaea46
AC		 2481 gsm_cleanup_mux(gsm);
2482 tty_kref_put(gsm->tty);
2483 gsm->tty = NULL;
2484}
2485
55db4c64 2486static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
0f3dcf3b 2487 const char *fp, int count)
e1eaea46
AC		 2488{
2489 struct gsm_mux *gsm = tty->disc_data;
82f91fe0 2490 char flags = TTY_NORMAL;
e1eaea46 2491
0a77c4f9
JP		 2492 if (debug & 4)
2493 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET,
2494 cp, count);
e1eaea46 2495
b93db97e
JS		 2496 for (; count; count--, cp++) {
2497 if (fp)
2498 flags = *fp++;
e1eaea46
AC		 2499 switch (flags) {
2500 case TTY_NORMAL:
b93db97e 2501 gsm->receive(gsm, *cp);
e1eaea46
AC		 2502 break;
2503 case TTY_OVERRUN:
2504 case TTY_BREAK:
2505 case TTY_PARITY:
2506 case TTY_FRAME:
b93db97e 2507 gsm_error(gsm, *cp, flags);
e1eaea46
AC		 2508 break;
2509 default:
c01af4fe 2510 WARN_ONCE(1, "%s: unknown flag %d\n",
429b4749 2511 tty_name(tty), flags);
e1eaea46
AC		 2512 break;
2513 }
2514 }
2515 /* FASYNC if needed ? */
2516 /* If clogged call tty_throttle(tty); */
2517}
2518
e1eaea46
AC		 2519/**
2520 * gsmld_flush_buffer - clean input queue
2521 * @tty: terminal device
2522 *
2523 * Flush the input buffer. Called when the line discipline is
2524 * being closed, when the tty layer wants the buffer flushed (eg
2525 * at hangup).
2526 */
2527
2528static void gsmld_flush_buffer(struct tty_struct *tty)
2529{
2530}
2531
2532/**
2533 * gsmld_close - close the ldisc for this tty
2534 * @tty: device
2535 *
2536 * Called from the terminal layer when this line discipline is
2537 * being shut down, either because of a close or becsuse of a
2538 * discipline change. The function will not be called while other
2539 * ldisc methods are in progress.
2540 */
2541
2542static void gsmld_close(struct tty_struct *tty)
2543{
2544 struct gsm_mux *gsm = tty->disc_data;
2545
2546 gsmld_detach_gsm(tty, gsm);
2547
2548 gsmld_flush_buffer(tty);
2549 /* Do other clean up here */
6ab8fba7 2550 mux_put(gsm);
e1eaea46
AC		 2551}
2552
2553/**
2554 * gsmld_open - open an ldisc
2555 * @tty: terminal to open
2556 *
2557 * Called when this line discipline is being attached to the
2558 * terminal device. Can sleep. Called serialized so that no
2559 * other events will occur in parallel. No further open will occur
2560 * until a close.
2561 */
2562
2563static int gsmld_open(struct tty_struct *tty)
2564{
2565 struct gsm_mux *gsm;
5a640967 2566 int ret;
e1eaea46
AC		 2567
2568 if (tty->ops->write == NULL)
2569 return -EINVAL;
2570
2571 /* Attach our ldisc data */
2572 gsm = gsm_alloc_mux();
2573 if (gsm == NULL)
2574 return -ENOMEM;
2575
2576 tty->disc_data = gsm;
2577 tty->receive_room = 65536;
2578
2579 /* Attach the initial passive connection */
2580 gsm->encoding = 1;
5a640967 2581
2582 ret = gsmld_attach_gsm(tty, gsm);
2583 if (ret != 0) {
2584 gsm_cleanup_mux(gsm);
2585 mux_put(gsm);
2586 }
2587 return ret;
e1eaea46
AC		 2588}
2589
2590/**
2591 * gsmld_write_wakeup - asynchronous I/O notifier
2592 * @tty: tty device
2593 *
2594 * Required for the ptys, serial driver etc. since processes
2595 * that attach themselves to the master and rely on ASYNC
2596 * IO must be woken up
2597 */
2598
2599static void gsmld_write_wakeup(struct tty_struct *tty)
2600{
2601 struct gsm_mux *gsm = tty->disc_data;
328be395 2602 unsigned long flags;
e1eaea46
AC		 2603
2604 /* Queue poll */
2605 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
5e44708f 2606 spin_lock_irqsave(&gsm->tx_lock, flags);
01dbb362 2607 gsm_data_kick(gsm, NULL);
328be395 2608 if (gsm->tx_bytes < TX_THRESH_LO) {
e1eaea46 2609 gsm_dlci_data_sweep(gsm);
328be395 2610 }
5e44708f 2611 spin_unlock_irqrestore(&gsm->tx_lock, flags);
e1eaea46
AC		 2612}
2613
2614/**
2615 * gsmld_read - read function for tty
2616 * @tty: tty device
2617 * @file: file object
2618 * @buf: userspace buffer pointer
2619 * @nr: size of I/O
542a121a
LJ		 2620 * @cookie: unused
2621 * @offset: unused
e1eaea46
AC		 2622 *
2623 * Perform reads for the line discipline. We are guaranteed that the
2624 * line discipline will not be closed under us but we may get multiple
2625 * parallel readers and must handle this ourselves. We may also get
2626 * a hangup. Always called in user context, may sleep.
2627 *
2628 * This code must be sure never to sleep through a hangup.
2629 */
2630
2631static ssize_t gsmld_read(struct tty_struct *tty, struct file *file,
3b830a9c
LT		 2632 unsigned char *buf, size_t nr,
2633 void **cookie, unsigned long offset)
e1eaea46
AC		 2634{
2635 return -EOPNOTSUPP;
2636}
2637
2638/**
2639 * gsmld_write - write function for tty
2640 * @tty: tty device
2641 * @file: file object
2642 * @buf: userspace buffer pointer
2643 * @nr: size of I/O
2644 *
2645 * Called when the owner of the device wants to send a frame
2646 * itself (or some other control data). The data is transferred
2647 * as-is and must be properly framed and checksummed as appropriate
2648 * by userspace. Frames are either sent whole or not at all as this
2649 * avoids pain user side.
2650 */
2651
2652static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
2653 const unsigned char *buf, size_t nr)
2654{
2655 int space = tty_write_room(tty);
2656 if (space >= nr)
2657 return tty->ops->write(tty, buf, nr);
2658 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2659 return -ENOBUFS;
2660}
2661
2662/**
2663 * gsmld_poll - poll method for N_GSM0710
2664 * @tty: terminal device
2665 * @file: file accessing it
2666 * @wait: poll table
2667 *
2668 * Called when the line discipline is asked to poll() for data or
2669 * for special events. This code is not serialized with respect to
2670 * other events save open/close.
2671 *
2672 * This code must be sure never to sleep through a hangup.
2673 * Called without the kernel lock held - fine
2674 */
2675
afc9a42b 2676static __poll_t gsmld_poll(struct tty_struct *tty, struct file *file,
e1eaea46
AC		 2677 poll_table *wait)
2678{
afc9a42b 2679 __poll_t mask = 0;
e1eaea46
AC		 2680 struct gsm_mux *gsm = tty->disc_data;
2681
2682 poll_wait(file, &tty->read_wait, wait);
2683 poll_wait(file, &tty->write_wait, wait);
2684 if (tty_hung_up_p(file))
a9a08845 2685 mask |= EPOLLHUP;
e1eaea46 2686 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
a9a08845 2687 mask |= EPOLLOUT | EPOLLWRNORM;
e1eaea46 2688 if (gsm->dead)
a9a08845 2689 mask |= EPOLLHUP;
e1eaea46
AC		 2690 return mask;
2691}
2692
e1eaea46
AC		 2693static int gsmld_ioctl(struct tty_struct *tty, struct file *file,
2694 unsigned int cmd, unsigned long arg)
2695{
2696 struct gsm_config c;
2697 struct gsm_mux *gsm = tty->disc_data;
a7b121b4 2698 unsigned int base;
e1eaea46
AC		 2699
2700 switch (cmd) {
2701 case GSMIOC_GETCONF:
33841040 2702 gsm_copy_config_values(gsm, &c);
edd05a73 2703 if (copy_to_user((void __user *)arg, &c, sizeof(c)))
e1eaea46
AC		 2704 return -EFAULT;
2705 return 0;
2706 case GSMIOC_SETCONF:
edd05a73 2707 if (copy_from_user(&c, (void __user *)arg, sizeof(c)))
e1eaea46 2708 return -EFAULT;
33841040 2709 return gsm_config(gsm, &c);
a7b121b4
MH		 2710 case GSMIOC_GETFIRST:
2711 base = mux_num_to_base(gsm);
2712 return put_user(base + 1, (__u32 __user *)arg);
e1eaea46 2713 default:
7c783601 2714 return n_tty_ioctl_helper(tty, cmd, arg);
e1eaea46
AC		 2715 }
2716}
2717
bcd5abe2
RG		 2718/*
2719 * Network interface
2720 *
2721 */
2722
2723static int gsm_mux_net_open(struct net_device *net)
2724{
2725 pr_debug("%s called\n", __func__);
2726 netif_start_queue(net);
2727 return 0;
2728}
2729
2730static int gsm_mux_net_close(struct net_device *net)
2731{
2732 netif_stop_queue(net);
2733 return 0;
2734}
2735
bcd5abe2
RG		 2736static void dlci_net_free(struct gsm_dlci *dlci)
2737{
2738 if (!dlci->net) {
2739 WARN_ON(1);
2740 return;
2741 }
2742 dlci->adaption = dlci->prev_adaption;
2743 dlci->data = dlci->prev_data;
2744 free_netdev(dlci->net);
2745 dlci->net = NULL;
2746}
2747static void net_free(struct kref *ref)
2748{
2749 struct gsm_mux_net *mux_net;
2750 struct gsm_dlci *dlci;
2751
2752 mux_net = container_of(ref, struct gsm_mux_net, ref);
2753 dlci = mux_net->dlci;
2754
2755 if (dlci->net) {
2756 unregister_netdev(dlci->net);
2757 dlci_net_free(dlci);
2758 }
2759}
2760
6ab8fba7
RG		 2761static inline void muxnet_get(struct gsm_mux_net *mux_net)
2762{
2763 kref_get(&mux_net->ref);
2764}
2765
2766static inline void muxnet_put(struct gsm_mux_net *mux_net)
2767{
2768 kref_put(&mux_net->ref, net_free);
2769}
2770
2468b3e4 2771static netdev_tx_t gsm_mux_net_start_xmit(struct sk_buff *skb,
bcd5abe2
RG		 2772 struct net_device *net)
2773{
5dbc32a8 2774 struct gsm_mux_net *mux_net = netdev_priv(net);
bcd5abe2 2775 struct gsm_dlci *dlci = mux_net->dlci;
6ab8fba7 2776 muxnet_get(mux_net);
bcd5abe2
RG		 2777
2778 skb_queue_head(&dlci->skb_list, skb);
47baf1ad
TK		 2779 net->stats.tx_packets++;
2780 net->stats.tx_bytes += skb->len;
bcd5abe2
RG		 2781 gsm_dlci_data_kick(dlci);
2782 /* And tell the kernel when the last transmit started. */
860e9538 2783 netif_trans_update(net);
6ab8fba7 2784 muxnet_put(mux_net);
bcd5abe2
RG		 2785 return NETDEV_TX_OK;
2786}
2787
2788/* called when a packet did not ack after watchdogtimeout */
0290bd29 2789static void gsm_mux_net_tx_timeout(struct net_device *net, unsigned int txqueue)
bcd5abe2
RG		 2790{
2791 /* Tell syslog we are hosed. */
2792 dev_dbg(&net->dev, "Tx timed out.\n");
2793
2794 /* Update statistics */
47baf1ad 2795 net->stats.tx_errors++;
bcd5abe2
RG		 2796}
2797
2798static void gsm_mux_rx_netchar(struct gsm_dlci *dlci,
4feb7a4a 2799 const unsigned char *in_buf, int size)
bcd5abe2
RG		 2800{
2801 struct net_device *net = dlci->net;
2802 struct sk_buff *skb;
5dbc32a8 2803 struct gsm_mux_net *mux_net = netdev_priv(net);
6ab8fba7 2804 muxnet_get(mux_net);
bcd5abe2
RG		 2805
2806 /* Allocate an sk_buff */
2807 skb = dev_alloc_skb(size + NET_IP_ALIGN);
2808 if (!skb) {
2809 /* We got no receive buffer. */
47baf1ad 2810 net->stats.rx_dropped++;
6ab8fba7 2811 muxnet_put(mux_net);
bcd5abe2
RG		 2812 return;
2813 }
2814 skb_reserve(skb, NET_IP_ALIGN);
59ae1d12 2815 skb_put_data(skb, in_buf, size);
bcd5abe2
RG		 2816
2817 skb->dev = net;
75406b3b 2818 skb->protocol = htons(ETH_P_IP);
bcd5abe2
RG		 2819
2820 /* Ship it off to the kernel */
2821 netif_rx(skb);
2822
2823 /* update out statistics */
47baf1ad
TK		 2824 net->stats.rx_packets++;
2825 net->stats.rx_bytes += size;
6ab8fba7 2826 muxnet_put(mux_net);
bcd5abe2
RG		 2827 return;
2828}
2829
bcd5abe2
RG		 2830static void gsm_mux_net_init(struct net_device *net)
2831{
2832 static const struct net_device_ops gsm_netdev_ops = {
2833 .ndo_open = gsm_mux_net_open,
2834 .ndo_stop = gsm_mux_net_close,
2835 .ndo_start_xmit = gsm_mux_net_start_xmit,
2836 .ndo_tx_timeout = gsm_mux_net_tx_timeout,
bcd5abe2
RG		 2837 };
2838
2839 net->netdev_ops = &gsm_netdev_ops;
2840
2841 /* fill in the other fields */
2842 net->watchdog_timeo = GSM_NET_TX_TIMEOUT;
2843 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
2844 net->type = ARPHRD_NONE;
2845 net->tx_queue_len = 10;
2846}
2847
2848
2849/* caller holds the dlci mutex */
2850static void gsm_destroy_network(struct gsm_dlci *dlci)
2851{
2852 struct gsm_mux_net *mux_net;
2853
d8ca4ecf 2854 pr_debug("destroy network interface\n");
bcd5abe2
RG		 2855 if (!dlci->net)
2856 return;
5dbc32a8 2857 mux_net = netdev_priv(dlci->net);
6ab8fba7 2858 muxnet_put(mux_net);
bcd5abe2
RG		 2859}
2860
2861
2862/* caller holds the dlci mutex */
2863static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
2864{
2865 char *netname;
2866 int retval = 0;
2867 struct net_device *net;
2868 struct gsm_mux_net *mux_net;
2869
2870 if (!capable(CAP_NET_ADMIN))
2871 return -EPERM;
2872
2873 /* Already in a non tty mode */
2874 if (dlci->adaption > 2)
2875 return -EBUSY;
2876
2877 if (nc->protocol != htons(ETH_P_IP))
2878 return -EPROTONOSUPPORT;
2879
2880 if (nc->adaption != 3 && nc->adaption != 4)
2881 return -EPROTONOSUPPORT;
2882
d8ca4ecf 2883 pr_debug("create network interface\n");
bcd5abe2
RG		 2884
2885 netname = "gsm%d";
2886 if (nc->if_name[0] != '\0')
2887 netname = nc->if_name;
c835a677
TG		 2888 net = alloc_netdev(sizeof(struct gsm_mux_net), netname,
2889 NET_NAME_UNKNOWN, gsm_mux_net_init);
bcd5abe2 2890 if (!net) {
d8ca4ecf 2891 pr_err("alloc_netdev failed\n");
bcd5abe2
RG		 2892 return -ENOMEM;
2893 }
2894 net->mtu = dlci->gsm->mtu;
9c22b4a3
JW		 2895 net->min_mtu = 8;
2896 net->max_mtu = dlci->gsm->mtu;
5dbc32a8 2897 mux_net = netdev_priv(net);
bcd5abe2
RG		 2898 mux_net->dlci = dlci;
2899 kref_init(&mux_net->ref);
2900 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */
2901
2902 /* reconfigure dlci for network */
2903 dlci->prev_adaption = dlci->adaption;
2904 dlci->prev_data = dlci->data;
2905 dlci->adaption = nc->adaption;
2906 dlci->data = gsm_mux_rx_netchar;
2907 dlci->net = net;
2908
d8ca4ecf 2909 pr_debug("register netdev\n");
bcd5abe2
RG		 2910 retval = register_netdev(net);
2911 if (retval) {
2912 pr_err("network register fail %d\n", retval);
2913 dlci_net_free(dlci);
2914 return retval;
2915 }
2916 return net->ifindex; /* return network index */
2917}
e1eaea46
AC		 2918
2919/* Line discipline for real tty */
d3157b2c 2920static struct tty_ldisc_ops tty_ldisc_packet = {
e1eaea46 2921 .owner = THIS_MODULE,
fbadf70a 2922 .num = N_GSM0710,
e1eaea46
AC		 2923 .name = "n_gsm",
2924 .open = gsmld_open,
2925 .close = gsmld_close,
2926 .flush_buffer = gsmld_flush_buffer,
e1eaea46
AC		 2927 .read = gsmld_read,
2928 .write = gsmld_write,
2929 .ioctl = gsmld_ioctl,
2930 .poll = gsmld_poll,
2931 .receive_buf = gsmld_receive_buf,
2932 .write_wakeup = gsmld_write_wakeup
2933};
2934
2935/*
2936 * Virtual tty side
2937 */
2938
2939#define TX_SIZE 512
2940
2941static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk)
2942{
2943 u8 modembits[5];
2944 struct gsm_control *ctrl;
2945 int len = 2;
2946
2947 if (brk)
2948 len++;
2949
2950 modembits[0] = len << 1 | EA; /* Data bytes */
2951 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */
2952 modembits[2] = gsm_encode_modem(dlci) << 1 | EA;
2953 if (brk)
2954 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */
2955 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1);
2956 if (ctrl == NULL)
2957 return -ENOMEM;
2958 return gsm_control_wait(dlci->gsm, ctrl);
2959}
2960
2961static int gsm_carrier_raised(struct tty_port *port)
2962{
2963 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
b2d89ad9
TL		 2964 struct gsm_mux *gsm = dlci->gsm;
2965
e1eaea46
AC		 2966 /* Not yet open so no carrier info */
2967 if (dlci->state != DLCI_OPEN)
2968 return 0;
2969 if (debug & 2)
2970 return 1;
b2d89ad9
TL		 2971
2972 /*
2973 * Basic mode with control channel in ADM mode may not respond
2974 * to CMD_MSC at all and modem_rx is empty.
2975 */
2976 if (gsm->encoding == 0 && gsm->dlci[0]->mode == DLCI_MODE_ADM &&
2977 !dlci->modem_rx)
2978 return 1;
2979
e1eaea46
AC		 2980 return dlci->modem_rx & TIOCM_CD;
2981}
2982
2983static void gsm_dtr_rts(struct tty_port *port, int onoff)
2984{
2985 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2986 unsigned int modem_tx = dlci->modem_tx;
2987 if (onoff)
2988 modem_tx |= TIOCM_DTR | TIOCM_RTS;
2989 else
2990 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
2991 if (modem_tx != dlci->modem_tx) {
2992 dlci->modem_tx = modem_tx;
2993 gsmtty_modem_update(dlci, 0);
2994 }
2995}
2996
2997static const struct tty_port_operations gsm_port_ops = {
2998 .carrier_raised = gsm_carrier_raised,
2999 .dtr_rts = gsm_dtr_rts,
9a8e62bc 3000 .destruct = gsm_dlci_free,
e1eaea46
AC		 3001};
3002
86176ed9 3003static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty)
e1eaea46
AC		 3004{
3005 struct gsm_mux *gsm;
3006 struct gsm_dlci *dlci;
e1eaea46 3007 unsigned int line = tty->index;
43a9e710 3008 unsigned int mux = mux_line_to_num(line);
86176ed9
JS		 3009 bool alloc = false;
3010 int ret;
e1eaea46
AC		 3011
3012 line = line & 0x3F;
3013
3014 if (mux >= MAX_MUX)
3015 return -ENXIO;
3016 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
3017 if (gsm_mux[mux] == NULL)
3018 return -EUNATCH;
3019 if (line == 0 || line > 61) /* 62/63 reserved */
3020 return -ECHRNG;
3021 gsm = gsm_mux[mux];
3022 if (gsm->dead)
3023 return -EL2HLT;
f3c909b4
AI		 3024 /* If DLCI 0 is not yet fully open return an error.
3025 This is ok from a locking
3026 perspective as we don't have to worry about this
3027 if DLCI0 is lost */
dfabf7ff
CB		 3028 mutex_lock(&gsm->mutex);
3029 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN) {
3030 mutex_unlock(&gsm->mutex);
7e8ac7b2 3031 return -EL2NSYNC;
dfabf7ff 3032 }
e1eaea46 3033 dlci = gsm->dlci[line];
86176ed9
JS		 3034 if (dlci == NULL) {
3035 alloc = true;
e1eaea46 3036 dlci = gsm_dlci_alloc(gsm, line);
86176ed9 3037 }
dfabf7ff
CB		 3038 if (dlci == NULL) {
3039 mutex_unlock(&gsm->mutex);
e1eaea46 3040 return -ENOMEM;
dfabf7ff 3041 }
86176ed9
JS		 3042 ret = tty_port_install(&dlci->port, driver, tty);
3043 if (ret) {
3044 if (alloc)
3045 dlci_put(dlci);
dfabf7ff 3046 mutex_unlock(&gsm->mutex);
86176ed9
JS		 3047 return ret;
3048 }
3049
dfabf7ff
CB		 3050 dlci_get(dlci);
3051 dlci_get(gsm->dlci[0]);
3052 mux_get(gsm);
e1eaea46 3053 tty->driver_data = dlci;
dfabf7ff 3054 mutex_unlock(&gsm->mutex);
86176ed9
JS		 3055
3056 return 0;
3057}
3058
3059static int gsmtty_open(struct tty_struct *tty, struct file *filp)
3060{
3061 struct gsm_dlci *dlci = tty->driver_data;
3062 struct tty_port *port = &dlci->port;
cbff2b32 3063 struct gsm_mux *gsm = dlci->gsm;
86176ed9
JS		 3064
3065 port->count++;
e1eaea46
AC		 3066 tty_port_tty_set(port, tty);
3067
3068 dlci->modem_rx = 0;
3069 /* We could in theory open and close before we wait - eg if we get
3070 a DM straight back. This is ok as that will have caused a hangup */
d41861ca 3071 tty_port_set_initialized(port, 1);
e1eaea46 3072 /* Start sending off SABM messages */
cbff2b32
ZZ		 3073 if (gsm->initiator)
3074 gsm_dlci_begin_open(dlci);
e1eaea46
AC		 3075 /* And wait for virtual carrier */
3076 return tty_port_block_til_ready(port, tty, filp);
3077}
3078
3079static void gsmtty_close(struct tty_struct *tty, struct file *filp)
3080{
3081 struct gsm_dlci *dlci = tty->driver_data;
6ab8fba7 3082
e1eaea46
AC		 3083 if (dlci == NULL)
3084 return;
4d9b1090
DB		 3085 if (dlci->state == DLCI_CLOSED)
3086 return;
bcd5abe2
RG		 3087 mutex_lock(&dlci->mutex);
3088 gsm_destroy_network(dlci);
3089 mutex_unlock(&dlci->mutex);
e1eaea46 3090 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
dfabf7ff 3091 return;
e1eaea46 3092 gsm_dlci_begin_close(dlci);
d41861ca
PH		 3093 if (tty_port_initialized(&dlci->port) && C_HUPCL(tty))
3094 tty_port_lower_dtr_rts(&dlci->port);
e1eaea46
AC		 3095 tty_port_close_end(&dlci->port, tty);
3096 tty_port_tty_set(&dlci->port, NULL);
dfabf7ff 3097 return;
e1eaea46
AC		 3098}
3099
3100static void gsmtty_hangup(struct tty_struct *tty)
3101{
3102 struct gsm_dlci *dlci = tty->driver_data;
4d9b1090
DB		 3103 if (dlci->state == DLCI_CLOSED)
3104 return;
e1eaea46
AC		 3105 tty_port_hangup(&dlci->port);
3106 gsm_dlci_begin_close(dlci);
3107}
3108
3109static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf,
3110 int len)
3111{
4d9b1090 3112 int sent;
e1eaea46 3113 struct gsm_dlci *dlci = tty->driver_data;
4d9b1090
DB		 3114 if (dlci->state == DLCI_CLOSED)
3115 return -EINVAL;
e1eaea46 3116 /* Stuff the bytes into the fifo queue */
036bca1f 3117 sent = kfifo_in_locked(&dlci->fifo, buf, len, &dlci->lock);
e1eaea46
AC		 3118 /* Need to kick the channel */
3119 gsm_dlci_data_kick(dlci);
3120 return sent;
3121}
3122
03b3b1a2 3123static unsigned int gsmtty_write_room(struct tty_struct *tty)
e1eaea46
AC		 3124{
3125 struct gsm_dlci *dlci = tty->driver_data;
4d9b1090 3126 if (dlci->state == DLCI_CLOSED)
6bfbfcfc 3127 return 0;
036bca1f 3128 return TX_SIZE - kfifo_len(&dlci->fifo);
e1eaea46
AC		 3129}
3130
fff4ef17 3131static unsigned int gsmtty_chars_in_buffer(struct tty_struct *tty)
e1eaea46
AC		 3132{
3133 struct gsm_dlci *dlci = tty->driver_data;
4d9b1090 3134 if (dlci->state == DLCI_CLOSED)
10eb63e5 3135 return 0;
036bca1f 3136 return kfifo_len(&dlci->fifo);
e1eaea46
AC		 3137}
3138
3139static void gsmtty_flush_buffer(struct tty_struct *tty)
3140{
3141 struct gsm_dlci *dlci = tty->driver_data;
4d9b1090
DB		 3142 if (dlci->state == DLCI_CLOSED)
3143 return;
e1eaea46
AC		 3144 /* Caution needed: If we implement reliable transport classes
3145 then the data being transmitted can't simply be junked once
3146 it has first hit the stack. Until then we can just blow it
3147 away */
036bca1f 3148 kfifo_reset(&dlci->fifo);
e1eaea46
AC		 3149 /* Need to unhook this DLCI from the transmit queue logic */
3150}
3151
3152static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
3153{
3154 /* The FIFO handles the queue so the kernel will do the right
3155 thing waiting on chars_in_buffer before calling us. No work
3156 to do here */
3157}
3158
60b33c13 3159static int gsmtty_tiocmget(struct tty_struct *tty)
e1eaea46
AC		 3160{
3161 struct gsm_dlci *dlci = tty->driver_data;
4d9b1090
DB		 3162 if (dlci->state == DLCI_CLOSED)
3163 return -EINVAL;
e1eaea46
AC		 3164 return dlci->modem_rx;
3165}
3166
20b9d177 3167static int gsmtty_tiocmset(struct tty_struct *tty,
e1eaea46
AC		 3168 unsigned int set, unsigned int clear)
3169{
3170 struct gsm_dlci *dlci = tty->driver_data;
3171 unsigned int modem_tx = dlci->modem_tx;
3172
4d9b1090
DB		 3173 if (dlci->state == DLCI_CLOSED)
3174 return -EINVAL;
cf16807b 3175 modem_tx &= ~clear;
e1eaea46
AC		 3176 modem_tx |= set;
3177
3178 if (modem_tx != dlci->modem_tx) {
3179 dlci->modem_tx = modem_tx;
3180 return gsmtty_modem_update(dlci, 0);
3181 }
3182 return 0;
3183}
3184
3185
6caa76b7 3186static int gsmtty_ioctl(struct tty_struct *tty,
e1eaea46
AC		 3187 unsigned int cmd, unsigned long arg)
3188{
bcd5abe2
RG		 3189 struct gsm_dlci *dlci = tty->driver_data;
3190 struct gsm_netconfig nc;
3191 int index;
3192
4d9b1090
DB		 3193 if (dlci->state == DLCI_CLOSED)
3194 return -EINVAL;
bcd5abe2
RG		 3195 switch (cmd) {
3196 case GSMIOC_ENABLE_NET:
3197 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc)))
3198 return -EFAULT;
3199 nc.if_name[IFNAMSIZ-1] = '\0';
3200 /* return net interface index or error code */
3201 mutex_lock(&dlci->mutex);
3202 index = gsm_create_network(dlci, &nc);
3203 mutex_unlock(&dlci->mutex);
3204 if (copy_to_user((void __user *)arg, &nc, sizeof(nc)))
3205 return -EFAULT;
3206 return index;
3207 case GSMIOC_DISABLE_NET:
3208 if (!capable(CAP_NET_ADMIN))
3209 return -EPERM;
3210 mutex_lock(&dlci->mutex);
3211 gsm_destroy_network(dlci);
3212 mutex_unlock(&dlci->mutex);
3213 return 0;
3214 default:
3215 return -ENOIOCTLCMD;
3216 }
e1eaea46
AC		 3217}
3218
3219static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old)
3220{
4d9b1090
DB		 3221 struct gsm_dlci *dlci = tty->driver_data;
3222 if (dlci->state == DLCI_CLOSED)
3223 return;
e1eaea46
AC		 3224 /* For the moment its fixed. In actual fact the speed information
3225 for the virtual channel can be propogated in both directions by
3226 the RPN control message. This however rapidly gets nasty as we
3227 then have to remap modem signals each way according to whether
3228 our virtual cable is null modem etc .. */
adc8d746 3229 tty_termios_copy_hw(&tty->termios, old);
e1eaea46
AC		 3230}
3231
3232static void gsmtty_throttle(struct tty_struct *tty)
3233{
3234 struct gsm_dlci *dlci = tty->driver_data;
4d9b1090
DB		 3235 if (dlci->state == DLCI_CLOSED)
3236 return;
9db276f8 3237 if (C_CRTSCTS(tty))
e1eaea46 3238 dlci->modem_tx &= ~TIOCM_DTR;
e9360b9a 3239 dlci->throttled = true;
e1eaea46
AC		 3240 /* Send an MSC with DTR cleared */
3241 gsmtty_modem_update(dlci, 0);
3242}
3243
3244static void gsmtty_unthrottle(struct tty_struct *tty)
3245{
3246 struct gsm_dlci *dlci = tty->driver_data;
4d9b1090
DB		 3247 if (dlci->state == DLCI_CLOSED)
3248 return;
9db276f8 3249 if (C_CRTSCTS(tty))
e1eaea46 3250 dlci->modem_tx |= TIOCM_DTR;
e9360b9a 3251 dlci->throttled = false;
e1eaea46
AC		 3252 /* Send an MSC with DTR set */
3253 gsmtty_modem_update(dlci, 0);
3254}
3255
3256static int gsmtty_break_ctl(struct tty_struct *tty, int state)
3257{
3258 struct gsm_dlci *dlci = tty->driver_data;
3259 int encode = 0; /* Off */
4d9b1090
DB		 3260 if (dlci->state == DLCI_CLOSED)
3261 return -EINVAL;
e1eaea46
AC		 3262
3263 if (state == -1) /* "On indefinitely" - we can't encode this
3264 properly */
3265 encode = 0x0F;
3266 else if (state > 0) {
3267 encode = state / 200; /* mS to encoding */
3268 if (encode > 0x0F)
3269 encode = 0x0F; /* Best effort */
3270 }
3271 return gsmtty_modem_update(dlci, encode);
3272}
3273
8f9cfeed 3274static void gsmtty_cleanup(struct tty_struct *tty)
dfabf7ff
CB		 3275{
3276 struct gsm_dlci *dlci = tty->driver_data;
3277 struct gsm_mux *gsm = dlci->gsm;
3278
3279 dlci_put(dlci);
3280 dlci_put(gsm->dlci[0]);
3281 mux_put(gsm);
dfabf7ff 3282}
e1eaea46
AC		 3283
3284/* Virtual ttys for the demux */
3285static const struct tty_operations gsmtty_ops = {
86176ed9 3286 .install = gsmtty_install,
e1eaea46
AC		 3287 .open = gsmtty_open,
3288 .close = gsmtty_close,
3289 .write = gsmtty_write,
3290 .write_room = gsmtty_write_room,
3291 .chars_in_buffer = gsmtty_chars_in_buffer,
3292 .flush_buffer = gsmtty_flush_buffer,
3293 .ioctl = gsmtty_ioctl,
3294 .throttle = gsmtty_throttle,
3295 .unthrottle = gsmtty_unthrottle,
3296 .set_termios = gsmtty_set_termios,
3297 .hangup = gsmtty_hangup,
3298 .wait_until_sent = gsmtty_wait_until_sent,
3299 .tiocmget = gsmtty_tiocmget,
3300 .tiocmset = gsmtty_tiocmset,
3301 .break_ctl = gsmtty_break_ctl,
8f9cfeed 3302 .cleanup = gsmtty_cleanup,
e1eaea46
AC		 3303};
3304
3305
3306
3307static int __init gsm_init(void)
3308{
3309 /* Fill in our line protocol discipline, and register it */
fbadf70a 3310 int status = tty_register_ldisc(&tty_ldisc_packet);
e1eaea46 3311 if (status != 0) {
5f9a31d6
AC		 3312 pr_err("n_gsm: can't register line discipline (err = %d)\n",
3313 status);
e1eaea46
AC		 3314 return status;
3315 }
3316
39b7b42b
JS		 3317 gsm_tty_driver = tty_alloc_driver(256, TTY_DRIVER_REAL_RAW |
3318 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_HARDWARE_BREAK);
3319 if (IS_ERR(gsm_tty_driver)) {
5f9a31d6 3320 pr_err("gsm_init: tty allocation failed.\n");
39b7b42b 3321 status = PTR_ERR(gsm_tty_driver);
839e0f22 3322 goto err_unreg_ldisc;
e1eaea46 3323 }
e1eaea46
AC		 3324 gsm_tty_driver->driver_name = "gsmtty";
3325 gsm_tty_driver->name = "gsmtty";
3326 gsm_tty_driver->major = 0; /* Dynamic */
3327 gsm_tty_driver->minor_start = 0;
3328 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
3329 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
e1eaea46
AC		 3330 gsm_tty_driver->init_termios = tty_std_termios;
3331 /* Fixme */
3332 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
3333 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
3334
e1eaea46 3335 if (tty_register_driver(gsm_tty_driver)) {
5f9a31d6 3336 pr_err("gsm_init: tty registration failed.\n");
839e0f22
JS		 3337 status = -EBUSY;
3338 goto err_put_driver;
e1eaea46 3339 }
5f9a31d6
AC		 3340 pr_debug("gsm_init: loaded as %d,%d.\n",
3341 gsm_tty_driver->major, gsm_tty_driver->minor_start);
e1eaea46 3342 return 0;
839e0f22 3343err_put_driver:
9f90a4dd 3344 tty_driver_kref_put(gsm_tty_driver);
839e0f22 3345err_unreg_ldisc:
f81ee8b8 3346 tty_unregister_ldisc(&tty_ldisc_packet);
839e0f22 3347 return status;
e1eaea46
AC		 3348}
3349
3350static void __exit gsm_exit(void)
3351{
357a6a87 3352 tty_unregister_ldisc(&tty_ldisc_packet);
e1eaea46 3353 tty_unregister_driver(gsm_tty_driver);
9f90a4dd 3354 tty_driver_kref_put(gsm_tty_driver);
e1eaea46
AC		 3355}
3356
3357module_init(gsm_init);
3358module_exit(gsm_exit);
3359
3360
3361MODULE_LICENSE("GPL");
3362MODULE_ALIAS_LDISC(N_GSM0710);
Linux 6.x block layer and io_uring tree(s)