1 // SPDX-License-Identifier: GPL-2.0
3 * n_gsm.c GSM 0710 tty multiplexor
4 * Copyright (c) 2009/10 Intel Corporation
5 * Copyright (c) 2022/23 Siemens Mobility GmbH
7 * * THIS IS A DEVELOPMENT SNAPSHOT IT IS NOT A FINAL RELEASE *
10 * tty -> DLCI fifo -> scheduler -> GSM MUX data queue ---o-> ldisc
11 * control message -> GSM MUX control queue --ยด
14 * ldisc -> gsm_queue() -o--> tty
15 * `-> gsm_control_response()
18 * Mostly done: ioctls for setting modes/timing
19 * Partly done: hooks so you can pull off frames to non tty devs
20 * Restart DLCI 0 when it closes ?
21 * Improve the tx engine
22 * Resolve tx side locking by adding a queue_head and routing
23 * all control traffic via it
24 * General tidy/document
25 * Review the locking/move to refcounts more (mux now moved to an
26 * alloc/free model ready)
27 * Use newest tty open/close port helpers and install hooks
28 * What to do about power functions ?
29 * Termios setting and negotiation
30 * Do we need a 'which mux are you' ioctl to correlate mux and tty sets
34 #include <linux/types.h>
35 #include <linux/major.h>
36 #include <linux/errno.h>
37 #include <linux/signal.h>
38 #include <linux/fcntl.h>
39 #include <linux/sched/signal.h>
40 #include <linux/interrupt.h>
41 #include <linux/tty.h>
42 #include <linux/bitfield.h>
43 #include <linux/ctype.h>
45 #include <linux/math.h>
46 #include <linux/nospec.h>
47 #include <linux/string.h>
48 #include <linux/slab.h>
49 #include <linux/poll.h>
50 #include <linux/bitops.h>
51 #include <linux/file.h>
52 #include <linux/uaccess.h>
53 #include <linux/module.h>
54 #include <linux/timer.h>
55 #include <linux/tty_flip.h>
56 #include <linux/tty_driver.h>
57 #include <linux/serial.h>
58 #include <linux/kfifo.h>
59 #include <linux/skbuff.h>
62 #include <linux/netdevice.h>
63 #include <linux/etherdevice.h>
64 #include <linux/gsmmux.h>
68 module_param(debug, int, 0600);
70 /* Module debug bits */
71 #define DBG_DUMP BIT(0) /* Data transmission dump. */
72 #define DBG_CD_ON BIT(1) /* Always assume CD line on. */
73 #define DBG_DATA BIT(2) /* Data transmission details. */
74 #define DBG_ERRORS BIT(3) /* Details for fail conditions. */
75 #define DBG_TTY BIT(4) /* Transmission statistics for DLCI TTYs. */
76 #define DBG_PAYLOAD BIT(5) /* Limits DBG_DUMP to payload frames. */
78 /* Defaults: these are from the specification */
80 #define T1 10 /* 100mS */
81 #define T2 34 /* 333mS */
82 #define T3 10 /* 10s */
83 #define N2 3 /* Retry 3 times */
84 #define K 2 /* outstanding I frames */
86 #define MAX_T3 255 /* In seconds. */
87 #define MAX_WINDOW_SIZE 7 /* Limit of K in error recovery mode. */
89 /* Use long timers for testing at low speed with debug on */
96 * Semi-arbitrary buffer size limits. 0710 is normally run with 32-64 byte
97 * limits so this is plenty
101 #define MIN_MTU (PROT_OVERHEAD + 1)
102 /* SOF, ADDR, CTRL, LEN1, LEN2, ..., FCS, EOF */
103 #define PROT_OVERHEAD 7
104 #define GSM_NET_TX_TIMEOUT (HZ*10)
107 * struct gsm_mux_net - network interface
109 * Created when net interface is initialized.
113 struct gsm_dlci *dlci;
117 * Each block of data we have queued to go out is in the form of
118 * a gsm_msg which holds everything we need in a link layer independent
123 struct list_head list;
124 u8 addr; /* DLCI address + flags */
125 u8 ctrl; /* Control byte + flags */
126 unsigned int len; /* Length of data block (can be zero) */
127 unsigned char *data; /* Points into buffer but not at the start */
128 unsigned char buffer[];
131 enum gsm_dlci_state {
133 DLCI_WAITING_CONFIG, /* Waiting for DLCI configuration from user */
134 DLCI_CONFIGURE, /* Sending PN (for adaption > 1) */
135 DLCI_OPENING, /* Sending SABM not seen UA */
136 DLCI_OPEN, /* SABM/UA complete */
137 DLCI_CLOSING, /* Sending DISC not seen UA/DM */
141 DLCI_MODE_ABM, /* Normal Asynchronous Balanced Mode */
142 DLCI_MODE_ADM, /* Asynchronous Disconnected Mode */
146 * Each active data link has a gsm_dlci structure associated which ties
147 * the link layer to an optional tty (if the tty side is open). To avoid
148 * complexity right now these are only ever freed up when the mux is
151 * At the moment we don't free DLCI objects until the mux is torn down
152 * this avoid object life time issues but might be worth review later.
158 enum gsm_dlci_state state;
162 enum gsm_dlci_mode mode;
163 spinlock_t lock; /* Protects the internal state */
164 struct timer_list t1; /* Retransmit timer for SABM and UA */
166 /* Uplink tty if active */
167 struct tty_port port; /* The tty bound to this DLCI if there is one */
168 #define TX_SIZE 4096 /* Must be power of 2. */
169 struct kfifo fifo; /* Queue fifo for the DLCI */
170 int adaption; /* Adaption layer in use */
172 u32 modem_rx; /* Our incoming virtual modem lines */
173 u32 modem_tx; /* Our outgoing modem lines */
175 bool dead; /* Refuse re-open */
177 u8 prio; /* Priority */
178 u8 ftype; /* Frame type */
179 u8 k; /* Window size */
181 bool throttled; /* Private copy of throttle state */
182 bool constipated; /* Throttle status for outgoing */
184 struct sk_buff *skb; /* Frame being sent */
185 struct sk_buff_head skb_list; /* Queued frames */
186 /* Data handling callback */
187 void (*data)(struct gsm_dlci *dlci, const u8 *data, int len);
188 void (*prev_data)(struct gsm_dlci *dlci, const u8 *data, int len);
189 struct net_device *net; /* network interface, if created */
193 * Parameter bits used for parameter negotiation according to 3GPP 27.010
197 struct gsm_dlci_param_bits {
207 static_assert(sizeof(struct gsm_dlci_param_bits) == 8);
209 #define PN_D_FIELD_DLCI GENMASK(5, 0)
210 #define PN_I_CL_FIELD_FTYPE GENMASK(3, 0)
211 #define PN_I_CL_FIELD_ADAPTION GENMASK(7, 4)
212 #define PN_P_FIELD_PRIO GENMASK(5, 0)
213 #define PN_T_FIELD_T1 GENMASK(7, 0)
214 #define PN_N_FIELD_N1 GENMASK(15, 0)
215 #define PN_NA_FIELD_N2 GENMASK(7, 0)
216 #define PN_K_FIELD_K GENMASK(2, 0)
218 /* Total number of supported devices */
219 #define GSM_TTY_MINORS 256
221 /* DLCI 0, 62/63 are special or reserved see gsmtty_open */
226 * DLCI 0 is used to pass control blocks out of band of the data
227 * flow (and with a higher link priority). One command can be outstanding
228 * at a time and we use this structure to manage them. They are created
229 * and destroyed by the user context, and updated by the receive paths
234 u8 cmd; /* Command we are issuing */
235 u8 *data; /* Data for the command in case we retransmit */
236 int len; /* Length of block for retransmission */
237 int done; /* Done flag */
238 int error; /* Error if any */
261 * Each GSM mux we have is represented by this structure. If we are
262 * operating as an ldisc then we use this structure as our ldisc
263 * state. We need to sort out lifetimes and locking with respect
264 * to the gsm mux array. For now we don't free DLCI objects that
265 * have been instantiated until the mux itself is terminated.
267 * To consider further: tty open versus mux shutdown.
271 struct tty_struct *tty; /* The tty our ldisc is bound to */
277 /* Events on the GSM channel */
278 wait_queue_head_t event;
280 /* ldisc send work */
281 struct work_struct tx_work;
283 /* Bits for GSM mode decoding */
287 enum gsm_mux_state state;
289 unsigned int address;
292 enum gsm_encoding encoding;
295 u8 *txframe; /* TX framing buffer */
297 /* Method for the receiver side */
298 void (*receive)(struct gsm_mux *gsm, u8 ch);
303 int initiator; /* Did we initiate connection */
304 bool dead; /* Has the mux been shut down */
305 struct gsm_dlci *dlci[NUM_DLCI];
306 int old_c_iflag; /* termios c_iflag value before attach */
307 bool constipated; /* Asked by remote to shut up */
308 bool has_devices; /* Devices were registered */
311 unsigned int tx_bytes; /* TX data outstanding */
312 #define TX_THRESH_HI 8192
313 #define TX_THRESH_LO 2048
314 struct list_head tx_ctrl_list; /* Pending control packets */
315 struct list_head tx_data_list; /* Pending data packets */
317 /* Control messages */
318 struct timer_list kick_timer; /* Kick TX queuing on timeout */
319 struct timer_list t2_timer; /* Retransmit timer for commands */
320 int cretries; /* Command retry counter */
321 struct gsm_control *pending_cmd;/* Our current pending command */
322 spinlock_t control_lock; /* Protects the pending command */
325 struct timer_list ka_timer; /* Keep-alive response timer */
326 u8 ka_num; /* Keep-alive match pattern */
327 signed int ka_retries; /* Keep-alive retry counter, -1 if not yet initialized */
330 int adaption; /* 1 or 2 supported */
331 u8 ftype; /* UI or UIH */
332 int t1, t2; /* Timers in 1/100th of a sec */
333 unsigned int t3; /* Power wake-up timer in seconds. */
334 int n2; /* Retry count */
335 u8 k; /* Window size */
336 bool wait_config; /* Wait for configuration by ioctl before DLCI open */
337 u32 keep_alive; /* Control channel keep-alive in 10ms */
339 /* Statistics (not currently exposed) */
340 unsigned long bad_fcs;
341 unsigned long malformed;
342 unsigned long io_error;
343 unsigned long open_error;
344 unsigned long bad_size;
345 unsigned long unsupported;
350 * Mux objects - needed so that we can translate a tty index into the
351 * relevant mux and DLCI.
354 #define MAX_MUX 4 /* 256 minors */
355 static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */
356 static DEFINE_SPINLOCK(gsm_mux_lock);
358 static struct tty_driver *gsm_tty_driver;
361 * This section of the driver logic implements the GSM encodings
362 * both the basic and the 'advanced'. Reliable transport is not
370 /* I is special: the rest are ..*/
381 /* Channel commands */
383 #define CMD_TEST 0x11
386 #define CMD_FCOFF 0x31
389 #define CMD_FCON 0x51
394 /* Virtual modem bits */
401 #define GSM0_SOF 0xF9
402 #define GSM1_SOF 0x7E
403 #define GSM1_ESCAPE 0x7D
404 #define GSM1_ESCAPE_BITS 0x20
407 #define ISO_IEC_646_MASK 0x7F
409 static const struct tty_port_operations gsm_port_ops;
412 * CRC table for GSM 0710
415 static const u8 gsm_fcs8[256] = {
416 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75,
417 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B,
418 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69,
419 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67,
420 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D,
421 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43,
422 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51,
423 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F,
424 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05,
425 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B,
426 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19,
427 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17,
428 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D,
429 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33,
430 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21,
431 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F,
432 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95,
433 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B,
434 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89,
435 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87,
436 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD,
437 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3,
438 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1,
439 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF,
440 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5,
441 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB,
442 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9,
443 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7,
444 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD,
445 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3,
446 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1,
447 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF
450 #define INIT_FCS 0xFF
451 #define GOOD_FCS 0xCF
453 static void gsm_dlci_close(struct gsm_dlci *dlci);
454 static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len);
455 static int gsm_modem_update(struct gsm_dlci *dlci, u8 brk);
456 static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
458 static int gsm_send_packet(struct gsm_mux *gsm, struct gsm_msg *msg);
459 static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr);
460 static void gsmld_write_trigger(struct gsm_mux *gsm);
461 static void gsmld_write_task(struct work_struct *work);
464 * gsm_fcs_add - update FCS
468 * Update the FCS to include c. Uses the algorithm in the specification
472 static inline u8 gsm_fcs_add(u8 fcs, u8 c)
474 return gsm_fcs8[fcs ^ c];
478 * gsm_fcs_add_block - update FCS for a block
481 * @len: length of buffer
483 * Update the FCS to include c. Uses the algorithm in the specification
487 static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len)
490 fcs = gsm_fcs8[fcs ^ *c++];
495 * gsm_read_ea - read a byte into an EA
496 * @val: variable holding value
497 * @c: byte going into the EA
499 * Processes one byte of an EA. Updates the passed variable
500 * and returns 1 if the EA is now completely read
503 static int gsm_read_ea(unsigned int *val, u8 c)
505 /* Add the next 7 bits into the value */
508 /* Was this the last byte of the EA 1 = yes*/
513 * gsm_read_ea_val - read a value until EA
514 * @val: variable holding value
515 * @data: buffer of data
516 * @dlen: length of data
518 * Processes an EA value. Updates the passed variable and
519 * returns the processed data length.
521 static unsigned int gsm_read_ea_val(unsigned int *val, const u8 *data, int dlen)
523 unsigned int len = 0;
525 for (; dlen > 0; dlen--) {
527 if (gsm_read_ea(val, *data++))
534 * gsm_encode_modem - encode modem data bits
535 * @dlci: DLCI to encode from
537 * Returns the correct GSM encoded modem status bits (6 bit field) for
538 * the current status of the DLCI and attached tty object
541 static u8 gsm_encode_modem(const struct gsm_dlci *dlci)
544 /* FC is true flow control not modem bits */
547 if (dlci->modem_tx & TIOCM_DTR)
548 modembits |= MDM_RTC;
549 if (dlci->modem_tx & TIOCM_RTS)
550 modembits |= MDM_RTR;
551 if (dlci->modem_tx & TIOCM_RI)
553 if (dlci->modem_tx & TIOCM_CD || dlci->gsm->initiator)
555 /* special mappings for passive side to operate as UE */
556 if (dlci->modem_tx & TIOCM_OUT1)
558 if (dlci->modem_tx & TIOCM_OUT2)
563 static void gsm_hex_dump_bytes(const char *fname, const u8 *data,
569 print_hex_dump(KERN_INFO, "", DUMP_PREFIX_NONE, 16, 1, data, len,
574 prefix = kasprintf(GFP_ATOMIC, "%s: ", fname);
577 print_hex_dump(KERN_INFO, prefix, DUMP_PREFIX_OFFSET, 16, 1, data, len,
583 * gsm_encode_params - encode DLCI parameters
584 * @dlci: DLCI to encode from
585 * @params: buffer to fill with the encoded parameters
587 * Encodes the parameters according to GSM 07.10 section 5.4.6.3.1
590 static int gsm_encode_params(const struct gsm_dlci *dlci,
591 struct gsm_dlci_param_bits *params)
593 const struct gsm_mux *gsm = dlci->gsm;
596 switch (dlci->ftype) {
604 pr_debug("unsupported frame type %d\n", dlci->ftype);
608 switch (dlci->adaption) {
609 case 1: /* Unstructured */
610 cl = 0; /* convergence layer type 1 */
612 case 2: /* Unstructured with modem bits. */
613 cl = 1; /* convergence layer type 2 */
616 pr_debug("unsupported adaption %d\n", dlci->adaption);
620 params->d_bits = FIELD_PREP(PN_D_FIELD_DLCI, dlci->addr);
621 /* UIH, convergence layer type 1 */
622 params->i_cl_bits = FIELD_PREP(PN_I_CL_FIELD_FTYPE, i) |
623 FIELD_PREP(PN_I_CL_FIELD_ADAPTION, cl);
624 params->p_bits = FIELD_PREP(PN_P_FIELD_PRIO, dlci->prio);
625 params->t_bits = FIELD_PREP(PN_T_FIELD_T1, gsm->t1);
626 params->n_bits = cpu_to_le16(FIELD_PREP(PN_N_FIELD_N1, dlci->mtu));
627 params->na_bits = FIELD_PREP(PN_NA_FIELD_N2, gsm->n2);
628 params->k_bits = FIELD_PREP(PN_K_FIELD_K, dlci->k);
634 * gsm_register_devices - register all tty devices for a given mux index
636 * @driver: the tty driver that describes the tty devices
637 * @index: the mux number is used to calculate the minor numbers of the
638 * ttys for this mux and may differ from the position in the
641 static int gsm_register_devices(struct tty_driver *driver, unsigned int index)
647 if (!driver || index >= MAX_MUX)
650 base = index * NUM_DLCI; /* first minor for this index */
651 for (i = 1; i < NUM_DLCI; i++) {
652 /* Don't register device 0 - this is the control channel
653 * and not a usable tty interface
655 dev = tty_register_device(gsm_tty_driver, base + i, NULL);
657 if (debug & DBG_ERRORS)
658 pr_info("%s failed to register device minor %u",
660 for (i--; i >= 1; i--)
661 tty_unregister_device(gsm_tty_driver, base + i);
670 * gsm_unregister_devices - unregister all tty devices for a given mux index
672 * @driver: the tty driver that describes the tty devices
673 * @index: the mux number is used to calculate the minor numbers of the
674 * ttys for this mux and may differ from the position in the
677 static void gsm_unregister_devices(struct tty_driver *driver,
683 if (!driver || index >= MAX_MUX)
686 base = index * NUM_DLCI; /* first minor for this index */
687 for (i = 1; i < NUM_DLCI; i++) {
688 /* Don't unregister device 0 - this is the control
689 * channel and not a usable tty interface
691 tty_unregister_device(gsm_tty_driver, base + i);
696 * gsm_print_packet - display a frame for debug
697 * @hdr: header to print before decode
698 * @addr: address EA from the frame
699 * @cr: C/R bit seen as initiator
700 * @control: control including PF bit
701 * @data: following data bytes
702 * @dlen: length of data
704 * Displays a packet in human readable format for debugging purposes. The
705 * style is based on amateur radio LAP-B dump display.
708 static void gsm_print_packet(const char *hdr, int addr, int cr,
709 u8 control, const u8 *data, int dlen)
711 if (!(debug & DBG_DUMP))
713 /* Only show user payload frames if debug & DBG_PAYLOAD */
714 if (!(debug & DBG_PAYLOAD) && addr != 0)
715 if ((control & ~PF) == UI || (control & ~PF) == UIH)
718 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]);
720 switch (control & ~PF) {
740 if (!(control & 0x01)) {
741 pr_cont("I N(S)%d N(R)%d",
742 (control & 0x0E) >> 1, (control & 0xE0) >> 5);
743 } else switch (control & 0x0F) {
745 pr_cont("RR(%d)", (control & 0xE0) >> 5);
748 pr_cont("RNR(%d)", (control & 0xE0) >> 5);
751 pr_cont("REJ(%d)", (control & 0xE0) >> 5);
754 pr_cont("[%02X]", control);
763 gsm_hex_dump_bytes(NULL, data, dlen);
768 * Link level transmission side
772 * gsm_stuff_frame - bytestuff a packet
773 * @input: input buffer
774 * @output: output buffer
775 * @len: length of input
777 * Expand a buffer by bytestuffing it. The worst case size change
778 * is doubling and the caller is responsible for handing out
779 * suitable sized buffers.
782 static int gsm_stuff_frame(const u8 *input, u8 *output, int len)
786 if (*input == GSM1_SOF || *input == GSM1_ESCAPE
787 || (*input & ISO_IEC_646_MASK) == XON
788 || (*input & ISO_IEC_646_MASK) == XOFF) {
789 *output++ = GSM1_ESCAPE;
790 *output++ = *input++ ^ GSM1_ESCAPE_BITS;
793 *output++ = *input++;
800 * gsm_send - send a control frame
802 * @addr: address for control frame
803 * @cr: command/response bit seen as initiator
804 * @control: control byte including PF bit
806 * Format up and transmit a control frame. These should be transmitted
807 * ahead of data when they are needed.
809 static int gsm_send(struct gsm_mux *gsm, int addr, int cr, int control)
816 msg = gsm_data_alloc(gsm, addr, 0, control);
820 /* toggle C/R coding if not initiator */
821 ocr = cr ^ (gsm->initiator ? 0 : 1);
825 *dp++ = (addr << 2) | (ocr << 1) | EA;
828 if (gsm->encoding == GSM_BASIC_OPT)
829 *dp++ = EA; /* Length of data = 0 */
831 *dp = 0xFF - gsm_fcs_add_block(INIT_FCS, msg->data, dp - msg->data);
832 msg->len = (dp - msg->data) + 1;
834 gsm_print_packet("Q->", addr, cr, control, NULL, 0);
836 spin_lock_irqsave(&gsm->tx_lock, flags);
837 list_add_tail(&msg->list, &gsm->tx_ctrl_list);
838 gsm->tx_bytes += msg->len;
839 spin_unlock_irqrestore(&gsm->tx_lock, flags);
840 gsmld_write_trigger(gsm);
846 * gsm_dlci_clear_queues - remove outstanding data for a DLCI
848 * @dlci: clear for this DLCI
850 * Clears the data queues for a given DLCI.
852 static void gsm_dlci_clear_queues(struct gsm_mux *gsm, struct gsm_dlci *dlci)
854 struct gsm_msg *msg, *nmsg;
855 int addr = dlci->addr;
858 /* Clear DLCI write fifo first */
859 spin_lock_irqsave(&dlci->lock, flags);
860 kfifo_reset(&dlci->fifo);
861 spin_unlock_irqrestore(&dlci->lock, flags);
863 /* Clear data packets in MUX write queue */
864 spin_lock_irqsave(&gsm->tx_lock, flags);
865 list_for_each_entry_safe(msg, nmsg, &gsm->tx_data_list, list) {
866 if (msg->addr != addr)
868 gsm->tx_bytes -= msg->len;
869 list_del(&msg->list);
872 spin_unlock_irqrestore(&gsm->tx_lock, flags);
876 * gsm_response - send a control response
878 * @addr: address for control frame
879 * @control: control byte including PF bit
881 * Format up and transmit a link level response frame.
884 static inline void gsm_response(struct gsm_mux *gsm, int addr, int control)
886 gsm_send(gsm, addr, 0, control);
890 * gsm_command - send a control command
892 * @addr: address for control frame
893 * @control: control byte including PF bit
895 * Format up and transmit a link level command frame.
898 static inline void gsm_command(struct gsm_mux *gsm, int addr, int control)
900 gsm_send(gsm, addr, 1, control);
903 /* Data transmission */
905 #define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */
908 * gsm_data_alloc - allocate data frame
910 * @addr: DLCI address
911 * @len: length excluding header and FCS
912 * @ctrl: control byte
914 * Allocate a new data buffer for sending frames with data. Space is left
915 * at the front for header bytes but that is treated as an implementation
916 * detail and not for the high level code to use
919 static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
922 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN,
926 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */
930 INIT_LIST_HEAD(&m->list);
935 * gsm_send_packet - sends a single packet
937 * @msg: packet to send
939 * The given packet is encoded and sent out. No memory is freed.
940 * The caller must hold the gsm tx lock.
942 static int gsm_send_packet(struct gsm_mux *gsm, struct gsm_msg *msg)
947 if (gsm->encoding == GSM_BASIC_OPT) {
948 gsm->txframe[0] = GSM0_SOF;
949 memcpy(gsm->txframe + 1, msg->data, msg->len);
950 gsm->txframe[msg->len + 1] = GSM0_SOF;
953 gsm->txframe[0] = GSM1_SOF;
954 len = gsm_stuff_frame(msg->data, gsm->txframe + 1, msg->len);
955 gsm->txframe[len + 1] = GSM1_SOF;
959 if (debug & DBG_DATA)
960 gsm_hex_dump_bytes(__func__, gsm->txframe, len);
961 gsm_print_packet("-->", msg->addr, gsm->initiator, msg->ctrl, msg->data,
964 ret = gsmld_output(gsm, gsm->txframe, len);
967 /* FIXME: Can eliminate one SOF in many more cases */
968 gsm->tx_bytes -= msg->len;
974 * gsm_is_flow_ctrl_msg - checks if flow control message
975 * @msg: message to check
977 * Returns true if the given message is a flow control command of the
978 * control channel. False is returned in any other case.
980 static bool gsm_is_flow_ctrl_msg(struct gsm_msg *msg)
987 switch (msg->ctrl & ~PF) {
991 if (gsm_read_ea_val(&cmd, msg->data + 2, msg->len - 2) < 1)
1005 * gsm_data_kick - poke the queue
1008 * The tty device has called us to indicate that room has appeared in
1009 * the transmit queue. Ram more data into the pipe if we have any.
1010 * If we have been flow-stopped by a CMD_FCOFF, then we can only
1011 * send messages on DLCI0 until CMD_FCON. The caller must hold
1014 static int gsm_data_kick(struct gsm_mux *gsm)
1016 struct gsm_msg *msg, *nmsg;
1017 struct gsm_dlci *dlci;
1020 clear_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
1022 /* Serialize control messages and control channel messages first */
1023 list_for_each_entry_safe(msg, nmsg, &gsm->tx_ctrl_list, list) {
1024 if (gsm->constipated && !gsm_is_flow_ctrl_msg(msg))
1026 ret = gsm_send_packet(gsm, msg);
1031 /* ldisc not open */
1032 gsm->tx_bytes -= msg->len;
1033 list_del(&msg->list);
1038 list_del(&msg->list);
1045 if (gsm->constipated)
1048 /* Serialize other channels */
1049 if (list_empty(&gsm->tx_data_list))
1051 list_for_each_entry_safe(msg, nmsg, &gsm->tx_data_list, list) {
1052 dlci = gsm->dlci[msg->addr];
1053 /* Send only messages for DLCIs with valid state */
1054 if (dlci->state != DLCI_OPEN) {
1055 gsm->tx_bytes -= msg->len;
1056 list_del(&msg->list);
1060 ret = gsm_send_packet(gsm, msg);
1065 /* ldisc not open */
1066 gsm->tx_bytes -= msg->len;
1067 list_del(&msg->list);
1072 list_del(&msg->list);
1083 * __gsm_data_queue - queue a UI or UIH frame
1084 * @dlci: DLCI sending the data
1085 * @msg: message queued
1087 * Add data to the transmit queue and try and get stuff moving
1088 * out of the mux tty if not already doing so. The Caller must hold
1092 static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
1094 struct gsm_mux *gsm = dlci->gsm;
1096 u8 *fcs = dp + msg->len;
1098 /* Fill in the header */
1099 if (gsm->encoding == GSM_BASIC_OPT) {
1101 *--dp = (msg->len << 1) | EA;
1103 *--dp = (msg->len >> 7); /* bits 7 - 15 */
1104 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */
1110 *--dp = (msg->addr << 2) | CR | EA;
1112 *--dp = (msg->addr << 2) | EA;
1113 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp);
1114 /* Ugly protocol layering violation */
1115 if (msg->ctrl == UI || msg->ctrl == (UI|PF))
1116 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len);
1119 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl,
1120 msg->data, msg->len);
1122 /* Move the header back and adjust the length, also allow for the FCS
1123 now tacked on the end */
1124 msg->len += (msg->data - dp) + 1;
1127 /* Add to the actual output queue */
1128 switch (msg->ctrl & ~PF) {
1131 if (msg->addr > 0) {
1132 list_add_tail(&msg->list, &gsm->tx_data_list);
1137 list_add_tail(&msg->list, &gsm->tx_ctrl_list);
1140 gsm->tx_bytes += msg->len;
1142 gsmld_write_trigger(gsm);
1143 mod_timer(&gsm->kick_timer, jiffies + 10 * gsm->t1 * HZ / 100);
1147 * gsm_data_queue - queue a UI or UIH frame
1148 * @dlci: DLCI sending the data
1149 * @msg: message queued
1151 * Add data to the transmit queue and try and get stuff moving
1152 * out of the mux tty if not already doing so. Take the
1153 * the gsm tx lock and dlci lock.
1156 static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
1158 unsigned long flags;
1159 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
1160 __gsm_data_queue(dlci, msg);
1161 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
1165 * gsm_dlci_data_output - try and push data out of a DLCI
1167 * @dlci: the DLCI to pull data from
1169 * Pull data from a DLCI and send it into the transmit queue if there
1170 * is data. Keep to the MRU of the mux. This path handles the usual tty
1171 * interface which is a byte stream with optional modem data.
1173 * Caller must hold the tx_lock of the mux.
1176 static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci)
1178 struct gsm_msg *msg;
1182 /* for modem bits without break data */
1183 h = ((dlci->adaption == 1) ? 0 : 1);
1185 len = kfifo_len(&dlci->fifo);
1189 /* MTU/MRU count only the data bits but watch adaption mode */
1190 if ((len + h) > dlci->mtu)
1191 len = dlci->mtu - h;
1195 msg = gsm_data_alloc(gsm, dlci->addr, size, dlci->ftype);
1199 switch (dlci->adaption) {
1200 case 1: /* Unstructured */
1202 case 2: /* Unstructured with modem bits.
1203 * Always one byte as we never send inline break data
1205 *dp++ = (gsm_encode_modem(dlci) << 1) | EA;
1208 pr_err("%s: unsupported adaption %d\n", __func__,
1213 WARN_ON(len != kfifo_out_locked(&dlci->fifo, dp, len,
1216 /* Notify upper layer about available send space. */
1217 tty_port_tty_wakeup(&dlci->port);
1219 __gsm_data_queue(dlci, msg);
1220 /* Bytes of data we used up */
1225 * gsm_dlci_data_output_framed - try and push data out of a DLCI
1227 * @dlci: the DLCI to pull data from
1229 * Pull data from a DLCI and send it into the transmit queue if there
1230 * is data. Keep to the MRU of the mux. This path handles framed data
1231 * queued as skbuffs to the DLCI.
1233 * Caller must hold the tx_lock of the mux.
1236 static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
1237 struct gsm_dlci *dlci)
1239 struct gsm_msg *msg;
1242 int last = 0, first = 0;
1245 /* One byte per frame is used for B/F flags */
1246 if (dlci->adaption == 4)
1249 /* dlci->skb is locked by tx_lock */
1250 if (dlci->skb == NULL) {
1251 dlci->skb = skb_dequeue_tail(&dlci->skb_list);
1252 if (dlci->skb == NULL)
1256 len = dlci->skb->len + overhead;
1258 /* MTU/MRU count only the data bits */
1259 if (len > dlci->mtu) {
1260 if (dlci->adaption == 3) {
1261 /* Over long frame, bin it */
1262 dev_kfree_skb_any(dlci->skb);
1270 size = len + overhead;
1271 msg = gsm_data_alloc(gsm, dlci->addr, size, dlci->ftype);
1273 skb_queue_tail(&dlci->skb_list, dlci->skb);
1279 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */
1280 /* Flag byte to carry the start/end info */
1281 *dp++ = last << 7 | first << 6 | 1; /* EA */
1284 memcpy(dp, dlci->skb->data, len);
1285 skb_pull(dlci->skb, len);
1286 __gsm_data_queue(dlci, msg);
1288 dev_kfree_skb_any(dlci->skb);
1295 * gsm_dlci_modem_output - try and push modem status out of a DLCI
1297 * @dlci: the DLCI to pull modem status from
1298 * @brk: break signal
1300 * Push an empty frame in to the transmit queue to update the modem status
1301 * bits and to transmit an optional break.
1303 * Caller must hold the tx_lock of the mux.
1306 static int gsm_dlci_modem_output(struct gsm_mux *gsm, struct gsm_dlci *dlci,
1310 struct gsm_msg *msg;
1313 /* for modem bits without break data */
1314 switch (dlci->adaption) {
1315 case 1: /* Unstructured */
1317 case 2: /* Unstructured with modem bits. */
1323 pr_err("%s: unsupported adaption %d\n", __func__,
1328 msg = gsm_data_alloc(gsm, dlci->addr, size, dlci->ftype);
1330 pr_err("%s: gsm_data_alloc error", __func__);
1334 switch (dlci->adaption) {
1335 case 1: /* Unstructured */
1337 case 2: /* Unstructured with modem bits. */
1339 *dp++ = (gsm_encode_modem(dlci) << 1) | EA;
1341 *dp++ = gsm_encode_modem(dlci) << 1;
1342 *dp++ = (brk << 4) | 2 | EA; /* Length, Break, EA */
1350 __gsm_data_queue(dlci, msg);
1355 * gsm_dlci_data_sweep - look for data to send
1358 * Sweep the GSM mux channels in priority order looking for ones with
1359 * data to send. We could do with optimising this scan a bit. We aim
1360 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit
1361 * TX_THRESH_LO we get called again
1363 * FIXME: We should round robin between groups and in theory you can
1364 * renegotiate DLCI priorities with optional stuff. Needs optimising.
1367 static int gsm_dlci_data_sweep(struct gsm_mux *gsm)
1369 /* Priority ordering: We should do priority with RR of the groups */
1370 int i, len, ret = 0;
1372 struct gsm_dlci *dlci;
1374 while (gsm->tx_bytes < TX_THRESH_HI) {
1375 for (sent = false, i = 1; i < NUM_DLCI; i++) {
1376 dlci = gsm->dlci[i];
1377 /* skip unused or blocked channel */
1378 if (!dlci || dlci->constipated)
1380 /* skip channels with invalid state */
1381 if (dlci->state != DLCI_OPEN)
1383 /* count the sent data per adaption */
1384 if (dlci->adaption < 3 && !dlci->net)
1385 len = gsm_dlci_data_output(gsm, dlci);
1387 len = gsm_dlci_data_output_framed(gsm, dlci);
1394 /* The lower DLCs can starve the higher DLCs! */
1407 * gsm_dlci_data_kick - transmit if possible
1408 * @dlci: DLCI to kick
1410 * Transmit data from this DLCI if the queue is empty. We can't rely on
1411 * a tty wakeup except when we filled the pipe so we need to fire off
1412 * new data ourselves in other cases.
1415 static void gsm_dlci_data_kick(struct gsm_dlci *dlci)
1417 unsigned long flags;
1420 if (dlci->constipated)
1423 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
1424 /* If we have nothing running then we need to fire up */
1425 sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO);
1426 if (dlci->gsm->tx_bytes == 0) {
1428 gsm_dlci_data_output_framed(dlci->gsm, dlci);
1430 gsm_dlci_data_output(dlci->gsm, dlci);
1433 gsm_dlci_data_sweep(dlci->gsm);
1434 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
1438 * Control message processing
1443 * gsm_control_command - send a command frame to a control
1445 * @cmd: the command to use
1446 * @data: data to follow encoded info
1447 * @dlen: length of data
1449 * Encode up and queue a UI/UIH frame containing our command.
1451 static int gsm_control_command(struct gsm_mux *gsm, int cmd, const u8 *data,
1454 struct gsm_msg *msg;
1455 struct gsm_dlci *dlci = gsm->dlci[0];
1457 msg = gsm_data_alloc(gsm, 0, dlen + 2, dlci->ftype);
1461 msg->data[0] = (cmd << 1) | CR | EA; /* Set C/R */
1462 msg->data[1] = (dlen << 1) | EA;
1463 memcpy(msg->data + 2, data, dlen);
1464 gsm_data_queue(dlci, msg);
1470 * gsm_control_reply - send a response frame to a control
1472 * @cmd: the command to use
1473 * @data: data to follow encoded info
1474 * @dlen: length of data
1476 * Encode up and queue a UI/UIH frame containing our response.
1479 static void gsm_control_reply(struct gsm_mux *gsm, int cmd, const u8 *data,
1482 struct gsm_msg *msg;
1483 struct gsm_dlci *dlci = gsm->dlci[0];
1485 msg = gsm_data_alloc(gsm, 0, dlen + 2, dlci->ftype);
1488 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */
1489 msg->data[1] = (dlen << 1) | EA;
1490 memcpy(msg->data + 2, data, dlen);
1491 gsm_data_queue(dlci, msg);
1495 * gsm_process_modem - process received modem status
1496 * @tty: virtual tty bound to the DLCI
1497 * @dlci: DLCI to affect
1498 * @modem: modem bits (full EA)
1499 * @slen: number of signal octets
1501 * Used when a modem control message or line state inline in adaption
1502 * layer 2 is processed. Sort out the local modem state and throttles
1505 static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
1506 u32 modem, int slen)
1512 /* The modem status command can either contain one octet (V.24 signals)
1513 * or two octets (V.24 signals + break signals). This is specified in
1514 * section 5.4.6.3.7 of the 07.10 mux spec.
1518 modem = modem & 0x7f;
1521 modem = (modem >> 7) & 0x7f;
1524 /* Flow control/ready to communicate */
1525 fc = (modem & MDM_FC) || !(modem & MDM_RTR);
1526 if (fc && !dlci->constipated) {
1527 /* Need to throttle our output on this device */
1528 dlci->constipated = true;
1529 } else if (!fc && dlci->constipated) {
1530 dlci->constipated = false;
1531 gsm_dlci_data_kick(dlci);
1534 /* Map modem bits */
1535 if (modem & MDM_RTC)
1536 mlines |= TIOCM_DSR | TIOCM_DTR;
1537 if (modem & MDM_RTR)
1538 mlines |= TIOCM_RTS | TIOCM_CTS;
1544 /* Carrier drop -> hangup */
1546 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD))
1551 tty_insert_flip_char(&dlci->port, 0, TTY_BREAK);
1552 dlci->modem_rx = mlines;
1553 wake_up_interruptible(&dlci->gsm->event);
1557 * gsm_process_negotiation - process received parameters
1559 * @addr: DLCI address
1560 * @cr: command/response
1561 * @params: encoded parameters from the parameter negotiation message
1563 * Used when the response for our parameter negotiation command was
1566 static int gsm_process_negotiation(struct gsm_mux *gsm, unsigned int addr,
1568 const struct gsm_dlci_param_bits *params)
1570 struct gsm_dlci *dlci = gsm->dlci[addr];
1571 unsigned int ftype, i, adaption, prio, n1, k;
1573 i = FIELD_GET(PN_I_CL_FIELD_FTYPE, params->i_cl_bits);
1574 adaption = FIELD_GET(PN_I_CL_FIELD_ADAPTION, params->i_cl_bits) + 1;
1575 prio = FIELD_GET(PN_P_FIELD_PRIO, params->p_bits);
1576 n1 = FIELD_GET(PN_N_FIELD_N1, get_unaligned_le16(¶ms->n_bits));
1577 k = FIELD_GET(PN_K_FIELD_K, params->k_bits);
1580 if (debug & DBG_ERRORS)
1581 pr_info("%s N1 out of range in PN\n", __func__);
1592 case 0x02: /* I frames are not supported */
1593 if (debug & DBG_ERRORS)
1594 pr_info("%s unsupported I frame request in PN\n",
1599 if (debug & DBG_ERRORS)
1600 pr_info("%s i out of range in PN\n", __func__);
1604 if (!cr && gsm->initiator) {
1605 if (adaption != dlci->adaption) {
1606 if (debug & DBG_ERRORS)
1607 pr_info("%s invalid adaption %d in PN\n",
1608 __func__, adaption);
1611 if (prio != dlci->prio) {
1612 if (debug & DBG_ERRORS)
1613 pr_info("%s invalid priority %d in PN",
1617 if (n1 > gsm->mru || n1 > dlci->mtu) {
1618 /* We requested a frame size but the other party wants
1619 * to send larger frames. The standard allows only a
1620 * smaller response value than requested (5.4.6.3.1).
1622 if (debug & DBG_ERRORS)
1623 pr_info("%s invalid N1 %d in PN\n", __func__,
1628 if (ftype != dlci->ftype) {
1629 if (debug & DBG_ERRORS)
1630 pr_info("%s invalid i %d in PN\n", __func__, i);
1633 if (ftype != UI && ftype != UIH && k > dlci->k) {
1634 if (debug & DBG_ERRORS)
1635 pr_info("%s invalid k %d in PN\n", __func__, k);
1639 } else if (cr && !gsm->initiator) {
1640 /* Only convergence layer type 1 and 2 are supported. */
1641 if (adaption != 1 && adaption != 2) {
1642 if (debug & DBG_ERRORS)
1643 pr_info("%s invalid adaption %d in PN\n",
1644 __func__, adaption);
1647 dlci->adaption = adaption;
1648 if (n1 > gsm->mru) {
1649 /* Propose a smaller value */
1650 dlci->mtu = gsm->mru;
1651 } else if (n1 > MAX_MTU) {
1652 /* Propose a smaller value */
1653 dlci->mtu = MAX_MTU;
1658 dlci->ftype = ftype;
1668 * gsm_control_modem - modem status received
1670 * @data: data following command
1671 * @clen: command length
1673 * We have received a modem status control message. This is used by
1674 * the GSM mux protocol to pass virtual modem line status and optionally
1675 * to indicate break signals. Unpack it, convert to Linux representation
1676 * and if need be stuff a break message down the tty.
1679 static void gsm_control_modem(struct gsm_mux *gsm, const u8 *data, int clen)
1681 unsigned int addr = 0;
1682 unsigned int modem = 0;
1683 struct gsm_dlci *dlci;
1686 const u8 *dp = data;
1687 struct tty_struct *tty;
1689 len = gsm_read_ea_val(&addr, data, cl);
1694 /* Closed port, or invalid ? */
1695 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1697 dlci = gsm->dlci[addr];
1699 /* Must be at least one byte following the EA */
1706 /* get the modem status */
1707 len = gsm_read_ea_val(&modem, dp, cl);
1711 tty = tty_port_tty_get(&dlci->port);
1712 gsm_process_modem(tty, dlci, modem, cl);
1717 gsm_control_reply(gsm, CMD_MSC, data, clen);
1721 * gsm_control_negotiation - parameter negotiation received
1723 * @cr: command/response flag
1724 * @data: data following command
1725 * @dlen: data length
1727 * We have received a parameter negotiation message. This is used by
1728 * the GSM mux protocol to configure protocol parameters for a new DLCI.
1730 static void gsm_control_negotiation(struct gsm_mux *gsm, unsigned int cr,
1731 const u8 *data, unsigned int dlen)
1734 struct gsm_dlci_param_bits pn_reply;
1735 struct gsm_dlci *dlci;
1736 struct gsm_dlci_param_bits *params;
1738 if (dlen < sizeof(struct gsm_dlci_param_bits)) {
1744 params = (struct gsm_dlci_param_bits *)data;
1745 addr = FIELD_GET(PN_D_FIELD_DLCI, params->d_bits);
1746 if (addr == 0 || addr >= NUM_DLCI || !gsm->dlci[addr]) {
1750 dlci = gsm->dlci[addr];
1752 /* Too late for parameter negotiation? */
1753 if ((!cr && dlci->state == DLCI_OPENING) || dlci->state == DLCI_OPEN) {
1758 /* Process the received parameters */
1759 if (gsm_process_negotiation(gsm, addr, cr, params) != 0) {
1760 /* Negotiation failed. Close the link. */
1761 if (debug & DBG_ERRORS)
1762 pr_info("%s PN failed\n", __func__);
1764 gsm_dlci_close(dlci);
1769 /* Reply command with accepted parameters. */
1770 if (gsm_encode_params(dlci, &pn_reply) == 0)
1771 gsm_control_reply(gsm, CMD_PN, (const u8 *)&pn_reply,
1773 else if (debug & DBG_ERRORS)
1774 pr_info("%s PN invalid\n", __func__);
1775 } else if (dlci->state == DLCI_CONFIGURE) {
1776 /* Proceed with link setup by sending SABM before UA */
1777 dlci->state = DLCI_OPENING;
1778 gsm_command(gsm, dlci->addr, SABM|PF);
1779 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1781 if (debug & DBG_ERRORS)
1782 pr_info("%s PN in invalid state\n", __func__);
1788 * gsm_control_rls - remote line status
1791 * @clen: data length
1793 * The modem sends us a two byte message on the control channel whenever
1794 * it wishes to send us an error state from the virtual link. Stuff
1795 * this into the uplink tty if present
1798 static void gsm_control_rls(struct gsm_mux *gsm, const u8 *data, int clen)
1800 struct tty_port *port;
1801 unsigned int addr = 0;
1804 const u8 *dp = data;
1806 while (gsm_read_ea(&addr, *dp++) == 0) {
1811 /* Must be at least one byte following ea */
1816 /* Closed port, or invalid ? */
1817 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1821 if ((bits & 1) == 0)
1824 port = &gsm->dlci[addr]->port;
1827 tty_insert_flip_char(port, 0, TTY_OVERRUN);
1829 tty_insert_flip_char(port, 0, TTY_PARITY);
1831 tty_insert_flip_char(port, 0, TTY_FRAME);
1833 tty_flip_buffer_push(port);
1835 gsm_control_reply(gsm, CMD_RLS, data, clen);
1838 static void gsm_dlci_begin_close(struct gsm_dlci *dlci);
1841 * gsm_control_message - DLCI 0 control processing
1843 * @command: the command EA
1844 * @data: data beyond the command/length EAs
1847 * Input processor for control messages from the other end of the link.
1848 * Processes the incoming request and queues a response frame or an
1849 * NSC response if not supported
1852 static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
1853 const u8 *data, int clen)
1859 struct gsm_dlci *dlci = gsm->dlci[0];
1860 /* Modem wishes to close down */
1864 gsm_dlci_begin_close(dlci);
1869 /* Modem wishes to test, reply with the data */
1870 gsm_control_reply(gsm, CMD_TEST, data, clen);
1873 /* Modem can accept data again */
1874 gsm->constipated = false;
1875 gsm_control_reply(gsm, CMD_FCON, NULL, 0);
1876 /* Kick the link in case it is idling */
1877 gsmld_write_trigger(gsm);
1880 /* Modem wants us to STFU */
1881 gsm->constipated = true;
1882 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0);
1885 /* Out of band modem line change indicator for a DLCI */
1886 gsm_control_modem(gsm, data, clen);
1889 /* Out of band error reception for a DLCI */
1890 gsm_control_rls(gsm, data, clen);
1893 /* Modem wishes to enter power saving state */
1894 gsm_control_reply(gsm, CMD_PSC, NULL, 0);
1896 /* Optional commands */
1898 /* Modem sends a parameter negotiation command */
1899 gsm_control_negotiation(gsm, 1, data, clen);
1901 /* Optional unsupported commands */
1902 case CMD_RPN: /* Remote port negotiation */
1903 case CMD_SNC: /* Service negotiation command */
1907 /* Reply to bad commands with an NSC */
1909 gsm_control_reply(gsm, CMD_NSC, buf, 1);
1915 * gsm_control_response - process a response to our control
1917 * @command: the command (response) EA
1918 * @data: data beyond the command/length EA
1921 * Process a response to an outstanding command. We only allow a single
1922 * control message in flight so this is fairly easy. All the clean up
1923 * is done by the caller, we just update the fields, flag it as done
1927 static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
1928 const u8 *data, int clen)
1930 struct gsm_control *ctrl;
1931 struct gsm_dlci *dlci;
1932 unsigned long flags;
1934 spin_lock_irqsave(&gsm->control_lock, flags);
1936 ctrl = gsm->pending_cmd;
1937 dlci = gsm->dlci[0];
1939 /* Does the reply match our command */
1940 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) {
1941 /* Our command was replied to, kill the retry timer */
1942 del_timer(&gsm->t2_timer);
1943 gsm->pending_cmd = NULL;
1944 /* Rejected by the other end */
1945 if (command == CMD_NSC)
1946 ctrl->error = -EOPNOTSUPP;
1948 wake_up(&gsm->event);
1949 /* Or did we receive the PN response to our PN command */
1950 } else if (command == CMD_PN) {
1951 gsm_control_negotiation(gsm, 0, data, clen);
1952 /* Or did we receive the TEST response to our TEST command */
1953 } else if (command == CMD_TEST && clen == 1 && *data == gsm->ka_num) {
1954 gsm->ka_retries = -1; /* trigger new keep-alive message */
1955 if (dlci && !dlci->dead)
1956 mod_timer(&gsm->ka_timer, jiffies + gsm->keep_alive * HZ / 100);
1958 spin_unlock_irqrestore(&gsm->control_lock, flags);
1962 * gsm_control_keep_alive - check timeout or start keep-alive
1963 * @t: timer contained in our gsm object
1965 * Called off the keep-alive timer expiry signaling that our link
1966 * partner is not responding anymore. Link will be closed.
1967 * This is also called to startup our timer.
1970 static void gsm_control_keep_alive(struct timer_list *t)
1972 struct gsm_mux *gsm = from_timer(gsm, t, ka_timer);
1973 unsigned long flags;
1975 spin_lock_irqsave(&gsm->control_lock, flags);
1976 if (gsm->ka_num && gsm->ka_retries == 0) {
1977 /* Keep-alive expired -> close the link */
1978 if (debug & DBG_ERRORS)
1979 pr_debug("%s keep-alive timed out\n", __func__);
1980 spin_unlock_irqrestore(&gsm->control_lock, flags);
1982 gsm_dlci_begin_close(gsm->dlci[0]);
1984 } else if (gsm->keep_alive && gsm->dlci[0] && !gsm->dlci[0]->dead) {
1985 if (gsm->ka_retries > 0) {
1986 /* T2 expired for keep-alive -> resend */
1989 /* Start keep-alive timer */
1993 gsm->ka_retries = (signed int)gsm->n2;
1995 gsm_control_command(gsm, CMD_TEST, &gsm->ka_num,
1996 sizeof(gsm->ka_num));
1997 mod_timer(&gsm->ka_timer,
1998 jiffies + gsm->t2 * HZ / 100);
2000 spin_unlock_irqrestore(&gsm->control_lock, flags);
2004 * gsm_control_transmit - send control packet
2006 * @ctrl: frame to send
2008 * Send out a pending control command (called under control lock)
2011 static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl)
2013 gsm_control_command(gsm, ctrl->cmd, ctrl->data, ctrl->len);
2017 * gsm_control_retransmit - retransmit a control frame
2018 * @t: timer contained in our gsm object
2020 * Called off the T2 timer expiry in order to retransmit control frames
2021 * that have been lost in the system somewhere. The control_lock protects
2022 * us from colliding with another sender or a receive completion event.
2023 * In that situation the timer may still occur in a small window but
2024 * gsm->pending_cmd will be NULL and we just let the timer expire.
2027 static void gsm_control_retransmit(struct timer_list *t)
2029 struct gsm_mux *gsm = from_timer(gsm, t, t2_timer);
2030 struct gsm_control *ctrl;
2031 unsigned long flags;
2032 spin_lock_irqsave(&gsm->control_lock, flags);
2033 ctrl = gsm->pending_cmd;
2035 if (gsm->cretries == 0 || !gsm->dlci[0] || gsm->dlci[0]->dead) {
2036 gsm->pending_cmd = NULL;
2037 ctrl->error = -ETIMEDOUT;
2039 spin_unlock_irqrestore(&gsm->control_lock, flags);
2040 wake_up(&gsm->event);
2044 gsm_control_transmit(gsm, ctrl);
2045 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
2047 spin_unlock_irqrestore(&gsm->control_lock, flags);
2051 * gsm_control_send - send a control frame on DLCI 0
2052 * @gsm: the GSM channel
2053 * @command: command to send including CR bit
2054 * @data: bytes of data (must be kmalloced)
2055 * @clen: length of the block to send
2057 * Queue and dispatch a control command. Only one command can be
2058 * active at a time. In theory more can be outstanding but the matching
2059 * gets really complicated so for now stick to one outstanding.
2062 static struct gsm_control *gsm_control_send(struct gsm_mux *gsm,
2063 unsigned int command, u8 *data, int clen)
2065 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control),
2067 unsigned long flags;
2071 wait_event(gsm->event, gsm->pending_cmd == NULL);
2072 spin_lock_irqsave(&gsm->control_lock, flags);
2073 if (gsm->pending_cmd != NULL) {
2074 spin_unlock_irqrestore(&gsm->control_lock, flags);
2077 ctrl->cmd = command;
2080 gsm->pending_cmd = ctrl;
2082 /* If DLCI0 is in ADM mode skip retries, it won't respond */
2083 if (gsm->dlci[0]->mode == DLCI_MODE_ADM)
2086 gsm->cretries = gsm->n2;
2088 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
2089 gsm_control_transmit(gsm, ctrl);
2090 spin_unlock_irqrestore(&gsm->control_lock, flags);
2095 * gsm_control_wait - wait for a control to finish
2097 * @control: control we are waiting on
2099 * Waits for the control to complete or time out. Frees any used
2100 * resources and returns 0 for success, or an error if the remote
2101 * rejected or ignored the request.
2104 static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
2107 wait_event(gsm->event, control->done == 1);
2108 err = control->error;
2115 * DLCI level handling: Needs krefs
2119 * State transitions and timers
2123 * gsm_dlci_close - a DLCI has closed
2124 * @dlci: DLCI that closed
2126 * Perform processing when moving a DLCI into closed state. If there
2127 * is an attached tty this is hung up
2130 static void gsm_dlci_close(struct gsm_dlci *dlci)
2132 del_timer(&dlci->t1);
2133 if (debug & DBG_ERRORS)
2134 pr_debug("DLCI %d goes closed.\n", dlci->addr);
2135 dlci->state = DLCI_CLOSED;
2136 /* Prevent us from sending data before the link is up again */
2137 dlci->constipated = true;
2138 if (dlci->addr != 0) {
2139 tty_port_tty_hangup(&dlci->port, false);
2140 gsm_dlci_clear_queues(dlci->gsm, dlci);
2141 /* Ensure that gsmtty_open() can return. */
2142 tty_port_set_initialized(&dlci->port, false);
2143 wake_up_interruptible(&dlci->port.open_wait);
2145 del_timer(&dlci->gsm->ka_timer);
2146 dlci->gsm->dead = true;
2148 /* A DLCI 0 close is a MUX termination so we need to kick that
2149 back to userspace somehow */
2150 gsm_dlci_data_kick(dlci);
2151 wake_up_all(&dlci->gsm->event);
2155 * gsm_dlci_open - a DLCI has opened
2156 * @dlci: DLCI that opened
2158 * Perform processing when moving a DLCI into open state.
2161 static void gsm_dlci_open(struct gsm_dlci *dlci)
2163 struct gsm_mux *gsm = dlci->gsm;
2165 /* Note that SABM UA .. SABM UA first UA lost can mean that we go
2167 del_timer(&dlci->t1);
2168 /* This will let a tty open continue */
2169 dlci->state = DLCI_OPEN;
2170 dlci->constipated = false;
2171 if (debug & DBG_ERRORS)
2172 pr_debug("DLCI %d goes open.\n", dlci->addr);
2173 /* Send current modem state */
2175 gsm_modem_update(dlci, 0);
2177 /* Start keep-alive control */
2179 gsm->ka_retries = -1;
2180 mod_timer(&gsm->ka_timer,
2181 jiffies + gsm->keep_alive * HZ / 100);
2183 gsm_dlci_data_kick(dlci);
2184 wake_up(&dlci->gsm->event);
2188 * gsm_dlci_negotiate - start parameter negotiation
2189 * @dlci: DLCI to open
2191 * Starts the parameter negotiation for the new DLCI. This needs to be done
2192 * before the DLCI initialized the channel via SABM.
2194 static int gsm_dlci_negotiate(struct gsm_dlci *dlci)
2196 struct gsm_mux *gsm = dlci->gsm;
2197 struct gsm_dlci_param_bits params;
2200 ret = gsm_encode_params(dlci, ¶ms);
2204 /* We cannot asynchronous wait for the command response with
2205 * gsm_command() and gsm_control_wait() at this point.
2207 ret = gsm_control_command(gsm, CMD_PN, (const u8 *)¶ms,
2214 * gsm_dlci_t1 - T1 timer expiry
2215 * @t: timer contained in the DLCI that opened
2217 * The T1 timer handles retransmits of control frames (essentially of
2218 * SABM and DISC). We resend the command until the retry count runs out
2219 * in which case an opening port goes back to closed and a closing port
2220 * is simply put into closed state (any further frames from the other
2221 * end will get a DM response)
2223 * Some control dlci can stay in ADM mode with other dlci working just
2224 * fine. In that case we can just keep the control dlci open after the
2225 * DLCI_OPENING retries time out.
2228 static void gsm_dlci_t1(struct timer_list *t)
2230 struct gsm_dlci *dlci = from_timer(dlci, t, t1);
2231 struct gsm_mux *gsm = dlci->gsm;
2233 switch (dlci->state) {
2234 case DLCI_CONFIGURE:
2235 if (dlci->retries && gsm_dlci_negotiate(dlci) == 0) {
2237 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
2240 gsm_dlci_begin_close(dlci); /* prevent half open link */
2244 if (dlci->retries) {
2246 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
2247 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
2248 } else if (!dlci->addr && gsm->control == (DM | PF)) {
2249 if (debug & DBG_ERRORS)
2250 pr_info("DLCI %d opening in ADM mode.\n",
2252 dlci->mode = DLCI_MODE_ADM;
2253 gsm_dlci_open(dlci);
2256 gsm_dlci_begin_close(dlci); /* prevent half open link */
2261 if (dlci->retries) {
2263 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
2264 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
2266 gsm_dlci_close(dlci);
2269 pr_debug("%s: unhandled state: %d\n", __func__, dlci->state);
2275 * gsm_dlci_begin_open - start channel open procedure
2276 * @dlci: DLCI to open
2278 * Commence opening a DLCI from the Linux side. We issue SABM messages
2279 * to the modem which should then reply with a UA or ADM, at which point
2280 * we will move into open state. Opening is done asynchronously with retry
2281 * running off timers and the responses.
2282 * Parameter negotiation is performed before SABM if required.
2285 static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
2287 struct gsm_mux *gsm = dlci ? dlci->gsm : NULL;
2288 bool need_pn = false;
2293 if (dlci->addr != 0) {
2294 if (gsm->adaption != 1 || gsm->adaption != dlci->adaption)
2296 if (dlci->prio != (roundup(dlci->addr + 1, 8) - 1))
2298 if (gsm->ftype != dlci->ftype)
2302 switch (dlci->state) {
2304 case DLCI_WAITING_CONFIG:
2306 dlci->retries = gsm->n2;
2308 dlci->state = DLCI_OPENING;
2309 gsm_command(gsm, dlci->addr, SABM|PF);
2311 /* Configure DLCI before setup */
2312 dlci->state = DLCI_CONFIGURE;
2313 if (gsm_dlci_negotiate(dlci) != 0) {
2314 gsm_dlci_close(dlci);
2318 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
2326 * gsm_dlci_set_opening - change state to opening
2327 * @dlci: DLCI to open
2329 * Change internal state to wait for DLCI open from initiator side.
2330 * We set off timers and responses upon reception of an SABM.
2332 static void gsm_dlci_set_opening(struct gsm_dlci *dlci)
2334 switch (dlci->state) {
2336 case DLCI_WAITING_CONFIG:
2338 dlci->state = DLCI_OPENING;
2346 * gsm_dlci_set_wait_config - wait for channel configuration
2347 * @dlci: DLCI to configure
2349 * Wait for a DLCI configuration from the application.
2351 static void gsm_dlci_set_wait_config(struct gsm_dlci *dlci)
2353 switch (dlci->state) {
2356 dlci->state = DLCI_WAITING_CONFIG;
2364 * gsm_dlci_begin_close - start channel open procedure
2365 * @dlci: DLCI to open
2367 * Commence closing a DLCI from the Linux side. We issue DISC messages
2368 * to the modem which should then reply with a UA, at which point we
2369 * will move into closed state. Closing is done asynchronously with retry
2370 * off timers. We may also receive a DM reply from the other end which
2371 * indicates the channel was already closed.
2374 static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
2376 struct gsm_mux *gsm = dlci->gsm;
2377 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
2379 dlci->retries = gsm->n2;
2380 dlci->state = DLCI_CLOSING;
2381 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
2382 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
2383 wake_up_interruptible(&gsm->event);
2387 * gsm_dlci_data - data arrived
2389 * @data: block of bytes received
2390 * @clen: length of received block
2392 * A UI or UIH frame has arrived which contains data for a channel
2393 * other than the control channel. If the relevant virtual tty is
2394 * open we shovel the bits down it, if not we drop them.
2397 static void gsm_dlci_data(struct gsm_dlci *dlci, const u8 *data, int clen)
2400 struct tty_port *port = &dlci->port;
2401 struct tty_struct *tty;
2402 unsigned int modem = 0;
2405 if (debug & DBG_TTY)
2406 pr_debug("%d bytes for tty\n", clen);
2407 switch (dlci->adaption) {
2408 /* Unsupported types */
2409 case 4: /* Packetised interruptible data */
2411 case 3: /* Packetised uininterruptible voice/data */
2413 case 2: /* Asynchronous serial with line state in each frame */
2414 len = gsm_read_ea_val(&modem, data, clen);
2417 tty = tty_port_tty_get(port);
2419 gsm_process_modem(tty, dlci, modem, len);
2423 /* Skip processed modem data */
2427 case 1: /* Line state will go via DLCI 0 controls only */
2429 tty_insert_flip_string(port, data, clen);
2430 tty_flip_buffer_push(port);
2435 * gsm_dlci_command - data arrived on control channel
2437 * @data: block of bytes received
2438 * @len: length of received block
2440 * A UI or UIH frame has arrived which contains data for DLCI 0 the
2441 * control channel. This should contain a command EA followed by
2442 * control data bytes. The command EA contains a command/response bit
2443 * and we divide up the work accordingly.
2446 static void gsm_dlci_command(struct gsm_dlci *dlci, const u8 *data, int len)
2448 /* See what command is involved */
2449 unsigned int command = 0;
2450 unsigned int clen = 0;
2453 /* read the command */
2454 dlen = gsm_read_ea_val(&command, data, len);
2458 /* read any control data */
2459 dlen = gsm_read_ea_val(&clen, data, len);
2463 /* Malformed command? */
2465 dlci->gsm->malformed++;
2470 gsm_control_message(dlci->gsm, command, data, clen);
2472 gsm_control_response(dlci->gsm, command, data, clen);
2476 * gsm_kick_timer - transmit if possible
2477 * @t: timer contained in our gsm object
2479 * Transmit data from DLCIs if the queue is empty. We can't rely on
2480 * a tty wakeup except when we filled the pipe so we need to fire off
2481 * new data ourselves in other cases.
2483 static void gsm_kick_timer(struct timer_list *t)
2485 struct gsm_mux *gsm = from_timer(gsm, t, kick_timer);
2486 unsigned long flags;
2489 spin_lock_irqsave(&gsm->tx_lock, flags);
2490 /* If we have nothing running then we need to fire up */
2491 if (gsm->tx_bytes < TX_THRESH_LO)
2492 sent = gsm_dlci_data_sweep(gsm);
2493 spin_unlock_irqrestore(&gsm->tx_lock, flags);
2495 if (sent && debug & DBG_DATA)
2496 pr_info("%s TX queue stalled\n", __func__);
2500 * gsm_dlci_copy_config_values - copy DLCI configuration
2501 * @dlci: source DLCI
2502 * @dc: configuration structure to fill
2504 static void gsm_dlci_copy_config_values(struct gsm_dlci *dlci, struct gsm_dlci_config *dc)
2506 memset(dc, 0, sizeof(*dc));
2507 dc->channel = (u32)dlci->addr;
2508 dc->adaption = (u32)dlci->adaption;
2509 dc->mtu = (u32)dlci->mtu;
2510 dc->priority = (u32)dlci->prio;
2511 if (dlci->ftype == UIH)
2515 dc->k = (u32)dlci->k;
2519 * gsm_dlci_config - configure DLCI from configuration
2520 * @dlci: DLCI to configure
2521 * @dc: DLCI configuration
2522 * @open: open DLCI after configuration?
2524 static int gsm_dlci_config(struct gsm_dlci *dlci, struct gsm_dlci_config *dc, int open)
2526 struct gsm_mux *gsm;
2527 bool need_restart = false;
2528 bool need_open = false;
2532 * Check that userspace doesn't put stuff in here to prevent breakages
2535 for (i = 0; i < ARRAY_SIZE(dc->reserved); i++)
2536 if (dc->reserved[i])
2543 /* Stuff we don't support yet - I frame transport */
2544 if (dc->adaption != 1 && dc->adaption != 2)
2546 if (dc->mtu > MAX_MTU || dc->mtu < MIN_MTU || dc->mtu > gsm->mru)
2548 if (dc->priority >= 64)
2550 if (dc->i == 0 || dc->i > 2) /* UIH and UI only */
2554 if (dc->flags & ~GSM_FL_RESTART) /* allow future extensions */
2558 * See what is needed for reconfiguration
2560 /* Framing fields */
2561 if (dc->adaption != dlci->adaption)
2562 need_restart = true;
2563 if (dc->mtu != dlci->mtu)
2564 need_restart = true;
2565 if (dc->i != dlci->ftype)
2566 need_restart = true;
2568 if (dc->priority != dlci->prio)
2569 need_restart = true;
2570 if (dc->flags & GSM_FL_RESTART)
2571 need_restart = true;
2573 if ((open && gsm->wait_config) || need_restart)
2575 if (dlci->state == DLCI_WAITING_CONFIG) {
2576 need_restart = false;
2581 * Close down what is needed, restart and initiate the new
2585 gsm_dlci_begin_close(dlci);
2586 wait_event_interruptible(gsm->event, dlci->state == DLCI_CLOSED);
2587 if (signal_pending(current))
2591 * Setup the new configuration values
2593 dlci->adaption = (int)dc->adaption;
2596 dlci->mtu = (unsigned int)dc->mtu;
2598 dlci->mtu = gsm->mtu;
2601 dlci->prio = (u8)dc->priority;
2603 dlci->prio = roundup(dlci->addr + 1, 8) - 1;
2607 else if (dc->i == 2)
2611 dlci->k = (u8)dc->k;
2617 gsm_dlci_begin_open(dlci);
2619 gsm_dlci_set_opening(dlci);
2626 * Allocate/Free DLCI channels
2630 * gsm_dlci_alloc - allocate a DLCI
2632 * @addr: address of the DLCI
2634 * Allocate and install a new DLCI object into the GSM mux.
2636 * FIXME: review locking races
2639 static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
2641 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC);
2644 spin_lock_init(&dlci->lock);
2645 mutex_init(&dlci->mutex);
2646 if (kfifo_alloc(&dlci->fifo, TX_SIZE, GFP_KERNEL) < 0) {
2651 skb_queue_head_init(&dlci->skb_list);
2652 timer_setup(&dlci->t1, gsm_dlci_t1, 0);
2653 tty_port_init(&dlci->port);
2654 dlci->port.ops = &gsm_port_ops;
2657 dlci->adaption = gsm->adaption;
2658 dlci->mtu = gsm->mtu;
2662 dlci->prio = roundup(addr + 1, 8) - 1;
2663 dlci->ftype = gsm->ftype;
2665 dlci->state = DLCI_CLOSED;
2667 dlci->data = gsm_dlci_data;
2668 /* Prevent us from sending data before the link is up */
2669 dlci->constipated = true;
2671 dlci->data = gsm_dlci_command;
2673 gsm->dlci[addr] = dlci;
2678 * gsm_dlci_free - free DLCI
2679 * @port: tty port for DLCI to free
2685 static void gsm_dlci_free(struct tty_port *port)
2687 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2689 timer_shutdown_sync(&dlci->t1);
2690 dlci->gsm->dlci[dlci->addr] = NULL;
2691 kfifo_free(&dlci->fifo);
2692 while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
2693 dev_kfree_skb(dlci->skb);
2697 static inline void dlci_get(struct gsm_dlci *dlci)
2699 tty_port_get(&dlci->port);
2702 static inline void dlci_put(struct gsm_dlci *dlci)
2704 tty_port_put(&dlci->port);
2707 static void gsm_destroy_network(struct gsm_dlci *dlci);
2710 * gsm_dlci_release - release DLCI
2711 * @dlci: DLCI to destroy
2713 * Release a DLCI. Actual free is deferred until either
2714 * mux is closed or tty is closed - whichever is last.
2718 static void gsm_dlci_release(struct gsm_dlci *dlci)
2720 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
2722 mutex_lock(&dlci->mutex);
2723 gsm_destroy_network(dlci);
2724 mutex_unlock(&dlci->mutex);
2726 /* We cannot use tty_hangup() because in tty_kref_put() the tty
2727 * driver assumes that the hangup queue is free and reuses it to
2728 * queue release_one_tty() -> NULL pointer panic in
2729 * process_one_work().
2733 tty_port_tty_set(&dlci->port, NULL);
2736 dlci->state = DLCI_CLOSED;
2741 * LAPBish link layer logic
2745 * gsm_queue - a GSM frame is ready to process
2746 * @gsm: pointer to our gsm mux
2748 * At this point in time a frame has arrived and been demangled from
2749 * the line encoding. All the differences between the encodings have
2750 * been handled below us and the frame is unpacked into the structures.
2751 * The fcs holds the header FCS but any data FCS must be added here.
2754 static void gsm_queue(struct gsm_mux *gsm)
2756 struct gsm_dlci *dlci;
2760 if (gsm->fcs != GOOD_FCS) {
2762 if (debug & DBG_DATA)
2763 pr_debug("BAD FCS %02x\n", gsm->fcs);
2766 address = gsm->address >> 1;
2767 if (address >= NUM_DLCI)
2770 cr = gsm->address & 1; /* C/R bit */
2771 cr ^= gsm->initiator ? 0 : 1; /* Flip so 1 always means command */
2773 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
2775 dlci = gsm->dlci[address];
2777 switch (gsm->control) {
2784 dlci = gsm_dlci_alloc(gsm, address);
2790 gsm_response(gsm, address, DM|PF);
2792 gsm_response(gsm, address, UA|PF);
2793 gsm_dlci_open(dlci);
2799 if (dlci == NULL || dlci->state == DLCI_CLOSED) {
2800 gsm_response(gsm, address, DM|PF);
2803 /* Real close complete */
2804 gsm_response(gsm, address, UA|PF);
2805 gsm_dlci_close(dlci);
2808 if (cr == 0 || dlci == NULL)
2810 switch (dlci->state) {
2812 gsm_dlci_close(dlci);
2815 gsm_dlci_open(dlci);
2818 pr_debug("%s: unhandled state: %d\n", __func__,
2823 case DM: /* DM can be valid unsolicited */
2829 gsm_dlci_close(dlci);
2835 if (dlci == NULL || dlci->state != DLCI_OPEN) {
2836 gsm_response(gsm, address, DM|PF);
2839 dlci->data(dlci, gsm->buf, gsm->len);
2852 * gsm0_receive - perform processing for non-transparency
2853 * @gsm: gsm data for this ldisc instance
2856 * Receive bytes in gsm mode 0
2859 static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
2863 switch (gsm->state) {
2864 case GSM_SEARCH: /* SOF marker */
2865 if (c == GSM0_SOF) {
2866 gsm->state = GSM_ADDRESS;
2869 gsm->fcs = INIT_FCS;
2872 case GSM_ADDRESS: /* Address EA */
2873 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2874 if (gsm_read_ea(&gsm->address, c))
2875 gsm->state = GSM_CONTROL;
2877 case GSM_CONTROL: /* Control Byte */
2878 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2880 gsm->state = GSM_LEN0;
2882 case GSM_LEN0: /* Length EA */
2883 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2884 if (gsm_read_ea(&gsm->len, c)) {
2885 if (gsm->len > gsm->mru) {
2887 gsm->state = GSM_SEARCH;
2892 gsm->state = GSM_FCS;
2894 gsm->state = GSM_DATA;
2897 gsm->state = GSM_LEN1;
2900 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2902 gsm->len |= len << 7;
2903 if (gsm->len > gsm->mru) {
2905 gsm->state = GSM_SEARCH;
2910 gsm->state = GSM_FCS;
2912 gsm->state = GSM_DATA;
2914 case GSM_DATA: /* Data */
2915 gsm->buf[gsm->count++] = c;
2916 if (gsm->count == gsm->len) {
2917 /* Calculate final FCS for UI frames over all data */
2918 if ((gsm->control & ~PF) != UIH) {
2919 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf,
2922 gsm->state = GSM_FCS;
2925 case GSM_FCS: /* FCS follows the packet */
2926 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2927 gsm->state = GSM_SSOF;
2930 gsm->state = GSM_SEARCH;
2937 pr_debug("%s: unhandled state: %d\n", __func__, gsm->state);
2943 * gsm1_receive - perform processing for non-transparency
2944 * @gsm: gsm data for this ldisc instance
2947 * Receive bytes in mode 1 (Advanced option)
2950 static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
2952 /* handle XON/XOFF */
2953 if ((c & ISO_IEC_646_MASK) == XON) {
2954 gsm->constipated = true;
2956 } else if ((c & ISO_IEC_646_MASK) == XOFF) {
2957 gsm->constipated = false;
2958 /* Kick the link in case it is idling */
2959 gsmld_write_trigger(gsm);
2962 if (c == GSM1_SOF) {
2963 /* EOF is only valid in frame if we have got to the data state */
2964 if (gsm->state == GSM_DATA) {
2965 if (gsm->count < 1) {
2968 gsm->state = GSM_START;
2971 /* Remove the FCS from data */
2973 if ((gsm->control & ~PF) != UIH) {
2974 /* Calculate final FCS for UI frames over all
2977 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf,
2980 /* Add the FCS itself to test against GOOD_FCS */
2981 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
2982 gsm->len = gsm->count;
2984 gsm->state = GSM_START;
2987 /* Any partial frame was a runt so go back to start */
2988 if (gsm->state != GSM_START) {
2989 if (gsm->state != GSM_SEARCH)
2991 gsm->state = GSM_START;
2993 /* A SOF in GSM_START means we are still reading idling or
2998 if (c == GSM1_ESCAPE) {
3003 /* Only an unescaped SOF gets us out of GSM search */
3004 if (gsm->state == GSM_SEARCH)
3008 c ^= GSM1_ESCAPE_BITS;
3009 gsm->escape = false;
3011 switch (gsm->state) {
3012 case GSM_START: /* First byte after SOF */
3014 gsm->state = GSM_ADDRESS;
3015 gsm->fcs = INIT_FCS;
3017 case GSM_ADDRESS: /* Address continuation */
3018 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
3019 if (gsm_read_ea(&gsm->address, c))
3020 gsm->state = GSM_CONTROL;
3022 case GSM_CONTROL: /* Control Byte */
3023 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
3026 gsm->state = GSM_DATA;
3028 case GSM_DATA: /* Data */
3029 if (gsm->count > gsm->mru) { /* Allow one for the FCS */
3030 gsm->state = GSM_OVERRUN;
3033 gsm->buf[gsm->count++] = c;
3035 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */
3038 pr_debug("%s: unhandled state: %d\n", __func__, gsm->state);
3044 * gsm_error - handle tty error
3047 * Handle an error in the receipt of data for a frame. Currently we just
3048 * go back to hunting for a SOF.
3050 * FIXME: better diagnostics ?
3053 static void gsm_error(struct gsm_mux *gsm)
3055 gsm->state = GSM_SEARCH;
3060 * gsm_cleanup_mux - generic GSM protocol cleanup
3062 * @disc: disconnect link?
3064 * Clean up the bits of the mux which are the same for all framing
3065 * protocols. Remove the mux from the mux table, stop all the timers
3066 * and then shut down each device hanging up the channels as we go.
3069 static void gsm_cleanup_mux(struct gsm_mux *gsm, bool disc)
3072 struct gsm_dlci *dlci;
3073 struct gsm_msg *txq, *ntxq;
3076 mutex_lock(&gsm->mutex);
3078 dlci = gsm->dlci[0];
3080 if (disc && dlci->state != DLCI_CLOSED) {
3081 gsm_dlci_begin_close(dlci);
3082 wait_event(gsm->event, dlci->state == DLCI_CLOSED);
3087 /* Finish outstanding timers, making sure they are done */
3088 del_timer_sync(&gsm->kick_timer);
3089 del_timer_sync(&gsm->t2_timer);
3090 del_timer_sync(&gsm->ka_timer);
3092 /* Finish writing to ldisc */
3093 flush_work(&gsm->tx_work);
3095 /* Free up any link layer users and finally the control channel */
3096 if (gsm->has_devices) {
3097 gsm_unregister_devices(gsm_tty_driver, gsm->num);
3098 gsm->has_devices = false;
3100 for (i = NUM_DLCI - 1; i >= 0; i--)
3102 gsm_dlci_release(gsm->dlci[i]);
3103 mutex_unlock(&gsm->mutex);
3104 /* Now wipe the queues */
3105 tty_ldisc_flush(gsm->tty);
3106 list_for_each_entry_safe(txq, ntxq, &gsm->tx_ctrl_list, list)
3108 INIT_LIST_HEAD(&gsm->tx_ctrl_list);
3109 list_for_each_entry_safe(txq, ntxq, &gsm->tx_data_list, list)
3111 INIT_LIST_HEAD(&gsm->tx_data_list);
3115 * gsm_activate_mux - generic GSM setup
3118 * Set up the bits of the mux which are the same for all framing
3119 * protocols. Add the mux to the mux table so it can be opened and
3120 * finally kick off connecting to DLCI 0 on the modem.
3123 static int gsm_activate_mux(struct gsm_mux *gsm)
3125 struct gsm_dlci *dlci;
3128 dlci = gsm_dlci_alloc(gsm, 0);
3132 if (gsm->encoding == GSM_BASIC_OPT)
3133 gsm->receive = gsm0_receive;
3135 gsm->receive = gsm1_receive;
3137 ret = gsm_register_devices(gsm_tty_driver, gsm->num);
3141 gsm->has_devices = true;
3142 gsm->dead = false; /* Tty opens are now permissible */
3147 * gsm_free_mux - free up a mux
3150 * Dispose of allocated resources for a dead mux
3152 static void gsm_free_mux(struct gsm_mux *gsm)
3156 for (i = 0; i < MAX_MUX; i++) {
3157 if (gsm == gsm_mux[i]) {
3162 mutex_destroy(&gsm->mutex);
3163 kfree(gsm->txframe);
3169 * gsm_free_muxr - free up a mux
3170 * @ref: kreference to the mux to free
3172 * Dispose of allocated resources for a dead mux
3174 static void gsm_free_muxr(struct kref *ref)
3176 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref);
3180 static inline void mux_get(struct gsm_mux *gsm)
3182 unsigned long flags;
3184 spin_lock_irqsave(&gsm_mux_lock, flags);
3185 kref_get(&gsm->ref);
3186 spin_unlock_irqrestore(&gsm_mux_lock, flags);
3189 static inline void mux_put(struct gsm_mux *gsm)
3191 unsigned long flags;
3193 spin_lock_irqsave(&gsm_mux_lock, flags);
3194 kref_put(&gsm->ref, gsm_free_muxr);
3195 spin_unlock_irqrestore(&gsm_mux_lock, flags);
3198 static inline unsigned int mux_num_to_base(struct gsm_mux *gsm)
3200 return gsm->num * NUM_DLCI;
3203 static inline unsigned int mux_line_to_num(unsigned int line)
3205 return line / NUM_DLCI;
3209 * gsm_alloc_mux - allocate a mux
3211 * Creates a new mux ready for activation.
3214 static struct gsm_mux *gsm_alloc_mux(void)
3217 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
3220 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL);
3221 if (gsm->buf == NULL) {
3225 gsm->txframe = kmalloc(2 * (MAX_MTU + PROT_OVERHEAD - 1), GFP_KERNEL);
3226 if (gsm->txframe == NULL) {
3231 spin_lock_init(&gsm->lock);
3232 mutex_init(&gsm->mutex);
3233 kref_init(&gsm->ref);
3234 INIT_LIST_HEAD(&gsm->tx_ctrl_list);
3235 INIT_LIST_HEAD(&gsm->tx_data_list);
3236 timer_setup(&gsm->kick_timer, gsm_kick_timer, 0);
3237 timer_setup(&gsm->t2_timer, gsm_control_retransmit, 0);
3238 timer_setup(&gsm->ka_timer, gsm_control_keep_alive, 0);
3239 INIT_WORK(&gsm->tx_work, gsmld_write_task);
3240 init_waitqueue_head(&gsm->event);
3241 spin_lock_init(&gsm->control_lock);
3242 spin_lock_init(&gsm->tx_lock);
3251 gsm->encoding = GSM_ADV_OPT;
3252 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
3254 gsm->dead = true; /* Avoid early tty opens */
3255 gsm->wait_config = false; /* Disabled */
3256 gsm->keep_alive = 0; /* Disabled */
3258 /* Store the instance to the mux array or abort if no space is
3261 spin_lock(&gsm_mux_lock);
3262 for (i = 0; i < MAX_MUX; i++) {
3269 spin_unlock(&gsm_mux_lock);
3271 mutex_destroy(&gsm->mutex);
3272 kfree(gsm->txframe);
3281 static void gsm_copy_config_values(struct gsm_mux *gsm,
3282 struct gsm_config *c)
3284 memset(c, 0, sizeof(*c));
3285 c->adaption = gsm->adaption;
3286 c->encapsulation = gsm->encoding;
3287 c->initiator = gsm->initiator;
3292 if (gsm->ftype == UIH)
3296 pr_debug("Ftype %d i %d\n", gsm->ftype, c->i);
3302 static int gsm_config(struct gsm_mux *gsm, struct gsm_config *c)
3305 int need_restart = 0;
3307 /* Stuff we don't support yet - UI or I frame transport */
3308 if (c->adaption != 1 && c->adaption != 2)
3310 /* Check the MRU/MTU range looks sane */
3311 if (c->mru < MIN_MTU || c->mtu < MIN_MTU)
3313 if (c->mru > MAX_MRU || c->mtu > MAX_MTU)
3319 if (c->encapsulation > 1) /* Basic, advanced, no I */
3321 if (c->initiator > 1)
3323 if (c->k > MAX_WINDOW_SIZE)
3325 if (c->i == 0 || c->i > 2) /* UIH and UI only */
3328 * See what is needed for reconfiguration
3332 if (c->t1 != 0 && c->t1 != gsm->t1)
3334 if (c->t2 != 0 && c->t2 != gsm->t2)
3336 if (c->encapsulation != gsm->encoding)
3338 if (c->adaption != gsm->adaption)
3341 if (c->initiator != gsm->initiator)
3343 if (c->mru != gsm->mru)
3345 if (c->mtu != gsm->mtu)
3349 * Close down what is needed, restart and initiate the new
3350 * configuration. On the first time there is no DLCI[0]
3351 * and closing or cleaning up is not necessary.
3353 if (need_close || need_restart)
3354 gsm_cleanup_mux(gsm, true);
3356 gsm->initiator = c->initiator;
3359 gsm->encoding = c->encapsulation ? GSM_ADV_OPT : GSM_BASIC_OPT;
3360 gsm->adaption = c->adaption;
3378 * FIXME: We need to separate activation/deactivation from adding
3379 * and removing from the mux array
3382 int ret = gsm_activate_mux(gsm);
3386 gsm_dlci_begin_open(gsm->dlci[0]);
3391 static void gsm_copy_config_ext_values(struct gsm_mux *gsm,
3392 struct gsm_config_ext *ce)
3394 memset(ce, 0, sizeof(*ce));
3395 ce->wait_config = gsm->wait_config ? 1 : 0;
3396 ce->keep_alive = gsm->keep_alive;
3399 static int gsm_config_ext(struct gsm_mux *gsm, struct gsm_config_ext *ce)
3401 bool need_restart = false;
3405 * Check that userspace doesn't put stuff in here to prevent breakages
3408 for (i = 0; i < ARRAY_SIZE(ce->reserved); i++)
3409 if (ce->reserved[i])
3411 if (ce->flags & ~GSM_FL_RESTART)
3415 if (ce->flags & GSM_FL_RESTART)
3416 need_restart = true;
3419 * Close down what is needed, restart and initiate the new
3420 * configuration. On the first time there is no DLCI[0]
3421 * and closing or cleaning up is not necessary.
3424 gsm_cleanup_mux(gsm, true);
3427 * Setup the new configuration values
3429 gsm->wait_config = ce->wait_config ? true : false;
3430 gsm->keep_alive = ce->keep_alive;
3433 int ret = gsm_activate_mux(gsm);
3437 gsm_dlci_begin_open(gsm->dlci[0]);
3444 * gsmld_output - write to link
3446 * @data: bytes to output
3449 * Write a block of data from the GSM mux to the data channel. This
3450 * will eventually be serialized from above but at the moment isn't.
3453 static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
3455 if (tty_write_room(gsm->tty) < len) {
3456 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
3459 if (debug & DBG_DATA)
3460 gsm_hex_dump_bytes(__func__, data, len);
3461 return gsm->tty->ops->write(gsm->tty, data, len);
3466 * gsmld_write_trigger - schedule ldisc write task
3469 static void gsmld_write_trigger(struct gsm_mux *gsm)
3471 if (!gsm || !gsm->dlci[0] || gsm->dlci[0]->dead)
3473 schedule_work(&gsm->tx_work);
3478 * gsmld_write_task - ldisc write task
3479 * @work: our tx write work
3481 * Writes out data to the ldisc if possible. We are doing this here to
3482 * avoid dead-locking. This returns if no space or data is left for output.
3484 static void gsmld_write_task(struct work_struct *work)
3486 struct gsm_mux *gsm = container_of(work, struct gsm_mux, tx_work);
3487 unsigned long flags;
3490 /* All outstanding control channel and control messages and one data
3494 spin_lock_irqsave(&gsm->tx_lock, flags);
3496 ret = gsm_data_kick(gsm);
3497 spin_unlock_irqrestore(&gsm->tx_lock, flags);
3500 for (i = 0; i < NUM_DLCI; i++)
3502 tty_port_tty_wakeup(&gsm->dlci[i]->port);
3506 * gsmld_attach_gsm - mode set up
3507 * @tty: our tty structure
3510 * Set up the MUX for basic mode and commence connecting to the
3511 * modem. Currently called from the line discipline set up but
3512 * will need moving to an ioctl path.
3515 static void gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
3517 gsm->tty = tty_kref_get(tty);
3518 /* Turn off tty XON/XOFF handling to handle it explicitly. */
3519 gsm->old_c_iflag = tty->termios.c_iflag;
3520 tty->termios.c_iflag &= (IXON | IXOFF);
3524 * gsmld_detach_gsm - stop doing 0710 mux
3525 * @tty: tty attached to the mux
3528 * Shutdown and then clean up the resources used by the line discipline
3531 static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
3533 WARN_ON(tty != gsm->tty);
3534 /* Restore tty XON/XOFF handling. */
3535 gsm->tty->termios.c_iflag = gsm->old_c_iflag;
3536 tty_kref_put(gsm->tty);
3540 static void gsmld_receive_buf(struct tty_struct *tty, const u8 *cp,
3541 const u8 *fp, size_t count)
3543 struct gsm_mux *gsm = tty->disc_data;
3544 char flags = TTY_NORMAL;
3546 if (debug & DBG_DATA)
3547 gsm_hex_dump_bytes(__func__, cp, count);
3549 for (; count; count--, cp++) {
3555 gsm->receive(gsm, *cp);
3564 WARN_ONCE(1, "%s: unknown flag %d\n",
3565 tty_name(tty), flags);
3569 /* FASYNC if needed ? */
3570 /* If clogged call tty_throttle(tty); */
3574 * gsmld_flush_buffer - clean input queue
3575 * @tty: terminal device
3577 * Flush the input buffer. Called when the line discipline is
3578 * being closed, when the tty layer wants the buffer flushed (eg
3582 static void gsmld_flush_buffer(struct tty_struct *tty)
3587 * gsmld_close - close the ldisc for this tty
3590 * Called from the terminal layer when this line discipline is
3591 * being shut down, either because of a close or becsuse of a
3592 * discipline change. The function will not be called while other
3593 * ldisc methods are in progress.
3596 static void gsmld_close(struct tty_struct *tty)
3598 struct gsm_mux *gsm = tty->disc_data;
3600 /* The ldisc locks and closes the port before calling our close. This
3601 * means we have no way to do a proper disconnect. We will not bother
3604 gsm_cleanup_mux(gsm, false);
3606 gsmld_detach_gsm(tty, gsm);
3608 gsmld_flush_buffer(tty);
3609 /* Do other clean up here */
3614 * gsmld_open - open an ldisc
3615 * @tty: terminal to open
3617 * Called when this line discipline is being attached to the
3618 * terminal device. Can sleep. Called serialized so that no
3619 * other events will occur in parallel. No further open will occur
3623 static int gsmld_open(struct tty_struct *tty)
3625 struct gsm_mux *gsm;
3627 if (!capable(CAP_NET_ADMIN))
3630 if (tty->ops->write == NULL)
3633 /* Attach our ldisc data */
3634 gsm = gsm_alloc_mux();
3638 tty->disc_data = gsm;
3639 tty->receive_room = 65536;
3641 /* Attach the initial passive connection */
3642 gsmld_attach_gsm(tty, gsm);
3644 /* The mux will not be activated yet, we wait for correct
3645 * configuration first.
3647 if (gsm->encoding == GSM_BASIC_OPT)
3648 gsm->receive = gsm0_receive;
3650 gsm->receive = gsm1_receive;
3656 * gsmld_write_wakeup - asynchronous I/O notifier
3659 * Required for the ptys, serial driver etc. since processes
3660 * that attach themselves to the master and rely on ASYNC
3661 * IO must be woken up
3664 static void gsmld_write_wakeup(struct tty_struct *tty)
3666 struct gsm_mux *gsm = tty->disc_data;
3669 gsmld_write_trigger(gsm);
3673 * gsmld_read - read function for tty
3675 * @file: file object
3676 * @buf: userspace buffer pointer
3681 * Perform reads for the line discipline. We are guaranteed that the
3682 * line discipline will not be closed under us but we may get multiple
3683 * parallel readers and must handle this ourselves. We may also get
3684 * a hangup. Always called in user context, may sleep.
3686 * This code must be sure never to sleep through a hangup.
3689 static ssize_t gsmld_read(struct tty_struct *tty, struct file *file, u8 *buf,
3690 size_t nr, void **cookie, unsigned long offset)
3696 * gsmld_write - write function for tty
3698 * @file: file object
3699 * @buf: userspace buffer pointer
3702 * Called when the owner of the device wants to send a frame
3703 * itself (or some other control data). The data is transferred
3704 * as-is and must be properly framed and checksummed as appropriate
3705 * by userspace. Frames are either sent whole or not at all as this
3706 * avoids pain user side.
3709 static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
3710 const u8 *buf, size_t nr)
3712 struct gsm_mux *gsm = tty->disc_data;
3713 unsigned long flags;
3721 spin_lock_irqsave(&gsm->tx_lock, flags);
3722 space = tty_write_room(tty);
3724 ret = tty->ops->write(tty, buf, nr);
3726 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
3727 spin_unlock_irqrestore(&gsm->tx_lock, flags);
3733 * gsmld_poll - poll method for N_GSM0710
3734 * @tty: terminal device
3735 * @file: file accessing it
3738 * Called when the line discipline is asked to poll() for data or
3739 * for special events. This code is not serialized with respect to
3740 * other events save open/close.
3742 * This code must be sure never to sleep through a hangup.
3743 * Called without the kernel lock held - fine
3746 static __poll_t gsmld_poll(struct tty_struct *tty, struct file *file,
3750 struct gsm_mux *gsm = tty->disc_data;
3752 poll_wait(file, &tty->read_wait, wait);
3753 poll_wait(file, &tty->write_wait, wait);
3757 if (tty_hung_up_p(file))
3759 if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
3761 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
3762 mask |= EPOLLOUT | EPOLLWRNORM;
3766 static int gsmld_ioctl(struct tty_struct *tty, unsigned int cmd,
3769 struct gsm_config c;
3770 struct gsm_config_ext ce;
3771 struct gsm_dlci_config dc;
3772 struct gsm_mux *gsm = tty->disc_data;
3773 unsigned int base, addr;
3774 struct gsm_dlci *dlci;
3777 case GSMIOC_GETCONF:
3778 gsm_copy_config_values(gsm, &c);
3779 if (copy_to_user((void __user *)arg, &c, sizeof(c)))
3782 case GSMIOC_SETCONF:
3783 if (copy_from_user(&c, (void __user *)arg, sizeof(c)))
3785 return gsm_config(gsm, &c);
3786 case GSMIOC_GETFIRST:
3787 base = mux_num_to_base(gsm);
3788 return put_user(base + 1, (__u32 __user *)arg);
3789 case GSMIOC_GETCONF_EXT:
3790 gsm_copy_config_ext_values(gsm, &ce);
3791 if (copy_to_user((void __user *)arg, &ce, sizeof(ce)))
3794 case GSMIOC_SETCONF_EXT:
3795 if (copy_from_user(&ce, (void __user *)arg, sizeof(ce)))
3797 return gsm_config_ext(gsm, &ce);
3798 case GSMIOC_GETCONF_DLCI:
3799 if (copy_from_user(&dc, (void __user *)arg, sizeof(dc)))
3801 if (dc.channel == 0 || dc.channel >= NUM_DLCI)
3803 addr = array_index_nospec(dc.channel, NUM_DLCI);
3804 dlci = gsm->dlci[addr];
3806 dlci = gsm_dlci_alloc(gsm, addr);
3810 gsm_dlci_copy_config_values(dlci, &dc);
3811 if (copy_to_user((void __user *)arg, &dc, sizeof(dc)))
3814 case GSMIOC_SETCONF_DLCI:
3815 if (copy_from_user(&dc, (void __user *)arg, sizeof(dc)))
3817 if (dc.channel == 0 || dc.channel >= NUM_DLCI)
3819 addr = array_index_nospec(dc.channel, NUM_DLCI);
3820 dlci = gsm->dlci[addr];
3822 dlci = gsm_dlci_alloc(gsm, addr);
3826 return gsm_dlci_config(dlci, &dc, 0);
3828 return n_tty_ioctl_helper(tty, cmd, arg);
3837 static int gsm_mux_net_open(struct net_device *net)
3839 pr_debug("%s called\n", __func__);
3840 netif_start_queue(net);
3844 static int gsm_mux_net_close(struct net_device *net)
3846 netif_stop_queue(net);
3850 static void dlci_net_free(struct gsm_dlci *dlci)
3856 dlci->adaption = dlci->prev_adaption;
3857 dlci->data = dlci->prev_data;
3858 free_netdev(dlci->net);
3861 static void net_free(struct kref *ref)
3863 struct gsm_mux_net *mux_net;
3864 struct gsm_dlci *dlci;
3866 mux_net = container_of(ref, struct gsm_mux_net, ref);
3867 dlci = mux_net->dlci;
3870 unregister_netdev(dlci->net);
3871 dlci_net_free(dlci);
3875 static inline void muxnet_get(struct gsm_mux_net *mux_net)
3877 kref_get(&mux_net->ref);
3880 static inline void muxnet_put(struct gsm_mux_net *mux_net)
3882 kref_put(&mux_net->ref, net_free);
3885 static netdev_tx_t gsm_mux_net_start_xmit(struct sk_buff *skb,
3886 struct net_device *net)
3888 struct gsm_mux_net *mux_net = netdev_priv(net);
3889 struct gsm_dlci *dlci = mux_net->dlci;
3890 muxnet_get(mux_net);
3892 skb_queue_head(&dlci->skb_list, skb);
3893 net->stats.tx_packets++;
3894 net->stats.tx_bytes += skb->len;
3895 gsm_dlci_data_kick(dlci);
3896 /* And tell the kernel when the last transmit started. */
3897 netif_trans_update(net);
3898 muxnet_put(mux_net);
3899 return NETDEV_TX_OK;
3902 /* called when a packet did not ack after watchdogtimeout */
3903 static void gsm_mux_net_tx_timeout(struct net_device *net, unsigned int txqueue)
3905 /* Tell syslog we are hosed. */
3906 dev_dbg(&net->dev, "Tx timed out.\n");
3908 /* Update statistics */
3909 net->stats.tx_errors++;
3912 static void gsm_mux_rx_netchar(struct gsm_dlci *dlci,
3913 const unsigned char *in_buf, int size)
3915 struct net_device *net = dlci->net;
3916 struct sk_buff *skb;
3917 struct gsm_mux_net *mux_net = netdev_priv(net);
3918 muxnet_get(mux_net);
3920 /* Allocate an sk_buff */
3921 skb = dev_alloc_skb(size + NET_IP_ALIGN);
3923 /* We got no receive buffer. */
3924 net->stats.rx_dropped++;
3925 muxnet_put(mux_net);
3928 skb_reserve(skb, NET_IP_ALIGN);
3929 skb_put_data(skb, in_buf, size);
3932 skb->protocol = htons(ETH_P_IP);
3934 /* Ship it off to the kernel */
3937 /* update out statistics */
3938 net->stats.rx_packets++;
3939 net->stats.rx_bytes += size;
3940 muxnet_put(mux_net);
3944 static void gsm_mux_net_init(struct net_device *net)
3946 static const struct net_device_ops gsm_netdev_ops = {
3947 .ndo_open = gsm_mux_net_open,
3948 .ndo_stop = gsm_mux_net_close,
3949 .ndo_start_xmit = gsm_mux_net_start_xmit,
3950 .ndo_tx_timeout = gsm_mux_net_tx_timeout,
3953 net->netdev_ops = &gsm_netdev_ops;
3955 /* fill in the other fields */
3956 net->watchdog_timeo = GSM_NET_TX_TIMEOUT;
3957 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
3958 net->type = ARPHRD_NONE;
3959 net->tx_queue_len = 10;
3963 /* caller holds the dlci mutex */
3964 static void gsm_destroy_network(struct gsm_dlci *dlci)
3966 struct gsm_mux_net *mux_net;
3968 pr_debug("destroy network interface\n");
3971 mux_net = netdev_priv(dlci->net);
3972 muxnet_put(mux_net);
3976 /* caller holds the dlci mutex */
3977 static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
3981 struct net_device *net;
3982 struct gsm_mux_net *mux_net;
3984 if (!capable(CAP_NET_ADMIN))
3987 /* Already in a non tty mode */
3988 if (dlci->adaption > 2)
3991 if (nc->protocol != htons(ETH_P_IP))
3992 return -EPROTONOSUPPORT;
3994 if (nc->adaption != 3 && nc->adaption != 4)
3995 return -EPROTONOSUPPORT;
3997 pr_debug("create network interface\n");
4000 if (nc->if_name[0] != '\0')
4001 netname = nc->if_name;
4002 net = alloc_netdev(sizeof(struct gsm_mux_net), netname,
4003 NET_NAME_UNKNOWN, gsm_mux_net_init);
4005 pr_err("alloc_netdev failed\n");
4008 net->mtu = dlci->mtu;
4009 net->min_mtu = MIN_MTU;
4010 net->max_mtu = dlci->mtu;
4011 mux_net = netdev_priv(net);
4012 mux_net->dlci = dlci;
4013 kref_init(&mux_net->ref);
4014 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */
4016 /* reconfigure dlci for network */
4017 dlci->prev_adaption = dlci->adaption;
4018 dlci->prev_data = dlci->data;
4019 dlci->adaption = nc->adaption;
4020 dlci->data = gsm_mux_rx_netchar;
4023 pr_debug("register netdev\n");
4024 retval = register_netdev(net);
4026 pr_err("network register fail %d\n", retval);
4027 dlci_net_free(dlci);
4030 return net->ifindex; /* return network index */
4033 /* Line discipline for real tty */
4034 static struct tty_ldisc_ops tty_ldisc_packet = {
4035 .owner = THIS_MODULE,
4039 .close = gsmld_close,
4040 .flush_buffer = gsmld_flush_buffer,
4042 .write = gsmld_write,
4043 .ioctl = gsmld_ioctl,
4045 .receive_buf = gsmld_receive_buf,
4046 .write_wakeup = gsmld_write_wakeup
4054 * gsm_modem_upd_via_data - send modem bits via convergence layer
4056 * @brk: break signal
4058 * Send an empty frame to signal mobile state changes and to transmit the
4059 * break signal for adaption 2.
4062 static void gsm_modem_upd_via_data(struct gsm_dlci *dlci, u8 brk)
4064 struct gsm_mux *gsm = dlci->gsm;
4065 unsigned long flags;
4067 if (dlci->state != DLCI_OPEN || dlci->adaption != 2)
4070 spin_lock_irqsave(&gsm->tx_lock, flags);
4071 gsm_dlci_modem_output(gsm, dlci, brk);
4072 spin_unlock_irqrestore(&gsm->tx_lock, flags);
4076 * gsm_modem_upd_via_msc - send modem bits via control frame
4078 * @brk: break signal
4081 static int gsm_modem_upd_via_msc(struct gsm_dlci *dlci, u8 brk)
4084 struct gsm_control *ctrl;
4087 if (dlci->gsm->encoding != GSM_BASIC_OPT)
4090 modembits[0] = (dlci->addr << 2) | 2 | EA; /* DLCI, Valid, EA */
4092 modembits[1] = (gsm_encode_modem(dlci) << 1) | EA;
4094 modembits[1] = gsm_encode_modem(dlci) << 1;
4095 modembits[2] = (brk << 4) | 2 | EA; /* Length, Break, EA */
4098 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len);
4101 return gsm_control_wait(dlci->gsm, ctrl);
4105 * gsm_modem_update - send modem status line state
4107 * @brk: break signal
4110 static int gsm_modem_update(struct gsm_dlci *dlci, u8 brk)
4112 if (dlci->gsm->dead)
4114 if (dlci->adaption == 2) {
4115 /* Send convergence layer type 2 empty data frame. */
4116 gsm_modem_upd_via_data(dlci, brk);
4118 } else if (dlci->gsm->encoding == GSM_BASIC_OPT) {
4119 /* Send as MSC control message. */
4120 return gsm_modem_upd_via_msc(dlci, brk);
4123 /* Modem status lines are not supported. */
4124 return -EPROTONOSUPPORT;
4128 * gsm_wait_modem_change - wait for modem status line change
4130 * @mask: modem status line bits
4132 * The function returns if:
4133 * - any given modem status line bit changed
4134 * - the wait event function got interrupted (e.g. by a signal)
4135 * - the underlying DLCI was closed
4136 * - the underlying ldisc device was removed
4138 static int gsm_wait_modem_change(struct gsm_dlci *dlci, u32 mask)
4140 struct gsm_mux *gsm = dlci->gsm;
4141 u32 old = dlci->modem_rx;
4144 ret = wait_event_interruptible(gsm->event, gsm->dead ||
4145 dlci->state != DLCI_OPEN ||
4146 (old ^ dlci->modem_rx) & mask);
4149 if (dlci->state != DLCI_OPEN)
4154 static bool gsm_carrier_raised(struct tty_port *port)
4156 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
4157 struct gsm_mux *gsm = dlci->gsm;
4159 /* Not yet open so no carrier info */
4160 if (dlci->state != DLCI_OPEN)
4162 if (debug & DBG_CD_ON)
4166 * Basic mode with control channel in ADM mode may not respond
4167 * to CMD_MSC at all and modem_rx is empty.
4169 if (gsm->encoding == GSM_BASIC_OPT &&
4170 gsm->dlci[0]->mode == DLCI_MODE_ADM && !dlci->modem_rx)
4173 return dlci->modem_rx & TIOCM_CD;
4176 static void gsm_dtr_rts(struct tty_port *port, bool active)
4178 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
4179 unsigned int modem_tx = dlci->modem_tx;
4181 modem_tx |= TIOCM_DTR | TIOCM_RTS;
4183 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
4184 if (modem_tx != dlci->modem_tx) {
4185 dlci->modem_tx = modem_tx;
4186 gsm_modem_update(dlci, 0);
4190 static const struct tty_port_operations gsm_port_ops = {
4191 .carrier_raised = gsm_carrier_raised,
4192 .dtr_rts = gsm_dtr_rts,
4193 .destruct = gsm_dlci_free,
4196 static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty)
4198 struct gsm_mux *gsm;
4199 struct gsm_dlci *dlci;
4200 unsigned int line = tty->index;
4201 unsigned int mux = mux_line_to_num(line);
4209 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
4210 if (gsm_mux[mux] == NULL)
4212 if (line == 0 || line > 61) /* 62/63 reserved */
4217 /* If DLCI 0 is not yet fully open return an error.
4218 This is ok from a locking
4219 perspective as we don't have to worry about this
4221 mutex_lock(&gsm->mutex);
4222 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN) {
4223 mutex_unlock(&gsm->mutex);
4226 dlci = gsm->dlci[line];
4229 dlci = gsm_dlci_alloc(gsm, line);
4232 mutex_unlock(&gsm->mutex);
4235 ret = tty_port_install(&dlci->port, driver, tty);
4239 mutex_unlock(&gsm->mutex);
4244 dlci_get(gsm->dlci[0]);
4246 tty->driver_data = dlci;
4247 mutex_unlock(&gsm->mutex);
4252 static int gsmtty_open(struct tty_struct *tty, struct file *filp)
4254 struct gsm_dlci *dlci = tty->driver_data;
4255 struct tty_port *port = &dlci->port;
4258 tty_port_tty_set(port, tty);
4261 /* We could in theory open and close before we wait - eg if we get
4262 a DM straight back. This is ok as that will have caused a hangup */
4263 tty_port_set_initialized(port, true);
4264 /* Start sending off SABM messages */
4265 if (!dlci->gsm->wait_config) {
4266 /* Start sending off SABM messages */
4267 if (dlci->gsm->initiator)
4268 gsm_dlci_begin_open(dlci);
4270 gsm_dlci_set_opening(dlci);
4272 gsm_dlci_set_wait_config(dlci);
4274 /* And wait for virtual carrier */
4275 return tty_port_block_til_ready(port, tty, filp);
4278 static void gsmtty_close(struct tty_struct *tty, struct file *filp)
4280 struct gsm_dlci *dlci = tty->driver_data;
4284 if (dlci->state == DLCI_CLOSED)
4286 mutex_lock(&dlci->mutex);
4287 gsm_destroy_network(dlci);
4288 mutex_unlock(&dlci->mutex);
4289 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
4291 gsm_dlci_begin_close(dlci);
4292 if (tty_port_initialized(&dlci->port) && C_HUPCL(tty))
4293 tty_port_lower_dtr_rts(&dlci->port);
4294 tty_port_close_end(&dlci->port, tty);
4295 tty_port_tty_set(&dlci->port, NULL);
4299 static void gsmtty_hangup(struct tty_struct *tty)
4301 struct gsm_dlci *dlci = tty->driver_data;
4302 if (dlci->state == DLCI_CLOSED)
4304 tty_port_hangup(&dlci->port);
4305 gsm_dlci_begin_close(dlci);
4308 static ssize_t gsmtty_write(struct tty_struct *tty, const u8 *buf, size_t len)
4311 struct gsm_dlci *dlci = tty->driver_data;
4312 if (dlci->state == DLCI_CLOSED)
4314 /* Stuff the bytes into the fifo queue */
4315 sent = kfifo_in_locked(&dlci->fifo, buf, len, &dlci->lock);
4316 /* Need to kick the channel */
4317 gsm_dlci_data_kick(dlci);
4321 static unsigned int gsmtty_write_room(struct tty_struct *tty)
4323 struct gsm_dlci *dlci = tty->driver_data;
4324 if (dlci->state == DLCI_CLOSED)
4326 return kfifo_avail(&dlci->fifo);
4329 static unsigned int gsmtty_chars_in_buffer(struct tty_struct *tty)
4331 struct gsm_dlci *dlci = tty->driver_data;
4332 if (dlci->state == DLCI_CLOSED)
4334 return kfifo_len(&dlci->fifo);
4337 static void gsmtty_flush_buffer(struct tty_struct *tty)
4339 struct gsm_dlci *dlci = tty->driver_data;
4340 unsigned long flags;
4342 if (dlci->state == DLCI_CLOSED)
4344 /* Caution needed: If we implement reliable transport classes
4345 then the data being transmitted can't simply be junked once
4346 it has first hit the stack. Until then we can just blow it
4348 spin_lock_irqsave(&dlci->lock, flags);
4349 kfifo_reset(&dlci->fifo);
4350 spin_unlock_irqrestore(&dlci->lock, flags);
4351 /* Need to unhook this DLCI from the transmit queue logic */
4354 static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
4356 /* The FIFO handles the queue so the kernel will do the right
4357 thing waiting on chars_in_buffer before calling us. No work
4361 static int gsmtty_tiocmget(struct tty_struct *tty)
4363 struct gsm_dlci *dlci = tty->driver_data;
4364 if (dlci->state == DLCI_CLOSED)
4366 return dlci->modem_rx;
4369 static int gsmtty_tiocmset(struct tty_struct *tty,
4370 unsigned int set, unsigned int clear)
4372 struct gsm_dlci *dlci = tty->driver_data;
4373 unsigned int modem_tx = dlci->modem_tx;
4375 if (dlci->state == DLCI_CLOSED)
4380 if (modem_tx != dlci->modem_tx) {
4381 dlci->modem_tx = modem_tx;
4382 return gsm_modem_update(dlci, 0);
4388 static int gsmtty_ioctl(struct tty_struct *tty,
4389 unsigned int cmd, unsigned long arg)
4391 struct gsm_dlci *dlci = tty->driver_data;
4392 struct gsm_netconfig nc;
4393 struct gsm_dlci_config dc;
4396 if (dlci->state == DLCI_CLOSED)
4399 case GSMIOC_ENABLE_NET:
4400 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc)))
4402 nc.if_name[IFNAMSIZ-1] = '\0';
4403 /* return net interface index or error code */
4404 mutex_lock(&dlci->mutex);
4405 index = gsm_create_network(dlci, &nc);
4406 mutex_unlock(&dlci->mutex);
4407 if (copy_to_user((void __user *)arg, &nc, sizeof(nc)))
4410 case GSMIOC_DISABLE_NET:
4411 if (!capable(CAP_NET_ADMIN))
4413 mutex_lock(&dlci->mutex);
4414 gsm_destroy_network(dlci);
4415 mutex_unlock(&dlci->mutex);
4417 case GSMIOC_GETCONF_DLCI:
4418 if (copy_from_user(&dc, (void __user *)arg, sizeof(dc)))
4420 if (dc.channel != dlci->addr)
4422 gsm_dlci_copy_config_values(dlci, &dc);
4423 if (copy_to_user((void __user *)arg, &dc, sizeof(dc)))
4426 case GSMIOC_SETCONF_DLCI:
4427 if (copy_from_user(&dc, (void __user *)arg, sizeof(dc)))
4429 if (dc.channel >= NUM_DLCI)
4431 if (dc.channel != 0 && dc.channel != dlci->addr)
4433 return gsm_dlci_config(dlci, &dc, 1);
4435 return gsm_wait_modem_change(dlci, (u32)arg);
4437 return -ENOIOCTLCMD;
4441 static void gsmtty_set_termios(struct tty_struct *tty,
4442 const struct ktermios *old)
4444 struct gsm_dlci *dlci = tty->driver_data;
4445 if (dlci->state == DLCI_CLOSED)
4447 /* For the moment its fixed. In actual fact the speed information
4448 for the virtual channel can be propogated in both directions by
4449 the RPN control message. This however rapidly gets nasty as we
4450 then have to remap modem signals each way according to whether
4451 our virtual cable is null modem etc .. */
4452 tty_termios_copy_hw(&tty->termios, old);
4455 static void gsmtty_throttle(struct tty_struct *tty)
4457 struct gsm_dlci *dlci = tty->driver_data;
4458 if (dlci->state == DLCI_CLOSED)
4461 dlci->modem_tx &= ~TIOCM_RTS;
4462 dlci->throttled = true;
4463 /* Send an MSC with RTS cleared */
4464 gsm_modem_update(dlci, 0);
4467 static void gsmtty_unthrottle(struct tty_struct *tty)
4469 struct gsm_dlci *dlci = tty->driver_data;
4470 if (dlci->state == DLCI_CLOSED)
4473 dlci->modem_tx |= TIOCM_RTS;
4474 dlci->throttled = false;
4475 /* Send an MSC with RTS set */
4476 gsm_modem_update(dlci, 0);
4479 static int gsmtty_break_ctl(struct tty_struct *tty, int state)
4481 struct gsm_dlci *dlci = tty->driver_data;
4482 int encode = 0; /* Off */
4483 if (dlci->state == DLCI_CLOSED)
4486 if (state == -1) /* "On indefinitely" - we can't encode this
4489 else if (state > 0) {
4490 encode = state / 200; /* mS to encoding */
4492 encode = 0x0F; /* Best effort */
4494 return gsm_modem_update(dlci, encode);
4497 static void gsmtty_cleanup(struct tty_struct *tty)
4499 struct gsm_dlci *dlci = tty->driver_data;
4500 struct gsm_mux *gsm = dlci->gsm;
4503 dlci_put(gsm->dlci[0]);
4507 /* Virtual ttys for the demux */
4508 static const struct tty_operations gsmtty_ops = {
4509 .install = gsmtty_install,
4510 .open = gsmtty_open,
4511 .close = gsmtty_close,
4512 .write = gsmtty_write,
4513 .write_room = gsmtty_write_room,
4514 .chars_in_buffer = gsmtty_chars_in_buffer,
4515 .flush_buffer = gsmtty_flush_buffer,
4516 .ioctl = gsmtty_ioctl,
4517 .throttle = gsmtty_throttle,
4518 .unthrottle = gsmtty_unthrottle,
4519 .set_termios = gsmtty_set_termios,
4520 .hangup = gsmtty_hangup,
4521 .wait_until_sent = gsmtty_wait_until_sent,
4522 .tiocmget = gsmtty_tiocmget,
4523 .tiocmset = gsmtty_tiocmset,
4524 .break_ctl = gsmtty_break_ctl,
4525 .cleanup = gsmtty_cleanup,
4530 static int __init gsm_init(void)
4532 /* Fill in our line protocol discipline, and register it */
4533 int status = tty_register_ldisc(&tty_ldisc_packet);
4535 pr_err("n_gsm: can't register line discipline (err = %d)\n",
4540 gsm_tty_driver = tty_alloc_driver(GSM_TTY_MINORS, TTY_DRIVER_REAL_RAW |
4541 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_HARDWARE_BREAK);
4542 if (IS_ERR(gsm_tty_driver)) {
4543 pr_err("gsm_init: tty allocation failed.\n");
4544 status = PTR_ERR(gsm_tty_driver);
4545 goto err_unreg_ldisc;
4547 gsm_tty_driver->driver_name = "gsmtty";
4548 gsm_tty_driver->name = "gsmtty";
4549 gsm_tty_driver->major = 0; /* Dynamic */
4550 gsm_tty_driver->minor_start = 0;
4551 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
4552 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
4553 gsm_tty_driver->init_termios = tty_std_termios;
4555 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
4556 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
4558 if (tty_register_driver(gsm_tty_driver)) {
4559 pr_err("gsm_init: tty registration failed.\n");
4561 goto err_put_driver;
4563 pr_debug("gsm_init: loaded as %d,%d.\n",
4564 gsm_tty_driver->major, gsm_tty_driver->minor_start);
4567 tty_driver_kref_put(gsm_tty_driver);
4569 tty_unregister_ldisc(&tty_ldisc_packet);
4573 static void __exit gsm_exit(void)
4575 tty_unregister_ldisc(&tty_ldisc_packet);
4576 tty_unregister_driver(gsm_tty_driver);
4577 tty_driver_kref_put(gsm_tty_driver);
4580 module_init(gsm_init);
4581 module_exit(gsm_exit);
4584 MODULE_LICENSE("GPL");
4585 MODULE_ALIAS_LDISC(N_GSM0710);