1 // SPDX-License-Identifier: GPL-2.0
3 * n_gsm.c GSM 0710 tty multiplexor
4 * Copyright (c) 2009/10 Intel Corporation
6 * * THIS IS A DEVELOPMENT SNAPSHOT IT IS NOT A FINAL RELEASE *
9 * tty -> DLCI fifo -> scheduler -> GSM MUX data queue ---o-> ldisc
10 * control message -> GSM MUX control queue --ยด
13 * ldisc -> gsm_queue() -o--> tty
14 * `-> gsm_control_response()
17 * Mostly done: ioctls for setting modes/timing
18 * Partly done: hooks so you can pull off frames to non tty devs
19 * Restart DLCI 0 when it closes ?
20 * Improve the tx engine
21 * Resolve tx side locking by adding a queue_head and routing
22 * all control traffic via it
23 * General tidy/document
24 * Review the locking/move to refcounts more (mux now moved to an
25 * alloc/free model ready)
26 * Use newest tty open/close port helpers and install hooks
27 * What to do about power functions ?
28 * Termios setting and negotiation
29 * Do we need a 'which mux are you' ioctl to correlate mux and tty sets
33 #include <linux/types.h>
34 #include <linux/major.h>
35 #include <linux/errno.h>
36 #include <linux/signal.h>
37 #include <linux/fcntl.h>
38 #include <linux/sched/signal.h>
39 #include <linux/interrupt.h>
40 #include <linux/tty.h>
41 #include <linux/ctype.h>
43 #include <linux/string.h>
44 #include <linux/slab.h>
45 #include <linux/poll.h>
46 #include <linux/bitops.h>
47 #include <linux/file.h>
48 #include <linux/uaccess.h>
49 #include <linux/module.h>
50 #include <linux/timer.h>
51 #include <linux/tty_flip.h>
52 #include <linux/tty_driver.h>
53 #include <linux/serial.h>
54 #include <linux/kfifo.h>
55 #include <linux/skbuff.h>
58 #include <linux/netdevice.h>
59 #include <linux/etherdevice.h>
60 #include <linux/gsmmux.h>
64 module_param(debug, int, 0600);
66 /* Defaults: these are from the specification */
68 #define T1 10 /* 100mS */
69 #define T2 34 /* 333mS */
70 #define N2 3 /* Retry 3 times */
72 /* Use long timers for testing at low speed with debug on */
79 * Semi-arbitrary buffer size limits. 0710 is normally run with 32-64 byte
80 * limits so this is plenty
84 /* SOF, ADDR, CTRL, LEN1, LEN2, ..., FCS, EOF */
85 #define PROT_OVERHEAD 7
86 #define GSM_NET_TX_TIMEOUT (HZ*10)
89 * struct gsm_mux_net - network interface
91 * Created when net interface is initialized.
95 struct gsm_dlci *dlci;
99 * Each block of data we have queued to go out is in the form of
100 * a gsm_msg which holds everything we need in a link layer independent
105 struct list_head list;
106 u8 addr; /* DLCI address + flags */
107 u8 ctrl; /* Control byte + flags */
108 unsigned int len; /* Length of data block (can be zero) */
109 unsigned char *data; /* Points into buffer but not at the start */
110 unsigned char buffer[];
113 enum gsm_dlci_state {
115 DLCI_OPENING, /* Sending SABM not seen UA */
116 DLCI_OPEN, /* SABM/UA complete */
117 DLCI_CLOSING, /* Sending DISC not seen UA/DM */
121 DLCI_MODE_ABM, /* Normal Asynchronous Balanced Mode */
122 DLCI_MODE_ADM, /* Asynchronous Disconnected Mode */
126 * Each active data link has a gsm_dlci structure associated which ties
127 * the link layer to an optional tty (if the tty side is open). To avoid
128 * complexity right now these are only ever freed up when the mux is
131 * At the moment we don't free DLCI objects until the mux is torn down
132 * this avoid object life time issues but might be worth review later.
138 enum gsm_dlci_state state;
142 enum gsm_dlci_mode mode;
143 spinlock_t lock; /* Protects the internal state */
144 struct timer_list t1; /* Retransmit timer for SABM and UA */
146 /* Uplink tty if active */
147 struct tty_port port; /* The tty bound to this DLCI if there is one */
148 #define TX_SIZE 4096 /* Must be power of 2. */
149 struct kfifo fifo; /* Queue fifo for the DLCI */
150 int adaption; /* Adaption layer in use */
152 u32 modem_rx; /* Our incoming virtual modem lines */
153 u32 modem_tx; /* Our outgoing modem lines */
154 bool dead; /* Refuse re-open */
156 bool throttled; /* Private copy of throttle state */
157 bool constipated; /* Throttle status for outgoing */
159 struct sk_buff *skb; /* Frame being sent */
160 struct sk_buff_head skb_list; /* Queued frames */
161 /* Data handling callback */
162 void (*data)(struct gsm_dlci *dlci, const u8 *data, int len);
163 void (*prev_data)(struct gsm_dlci *dlci, const u8 *data, int len);
164 struct net_device *net; /* network interface, if created */
167 /* DLCI 0, 62/63 are special or reserved see gsmtty_open */
172 * DLCI 0 is used to pass control blocks out of band of the data
173 * flow (and with a higher link priority). One command can be outstanding
174 * at a time and we use this structure to manage them. They are created
175 * and destroyed by the user context, and updated by the receive paths
180 u8 cmd; /* Command we are issuing */
181 u8 *data; /* Data for the command in case we retransmit */
182 int len; /* Length of block for retransmission */
183 int done; /* Done flag */
184 int error; /* Error if any */
202 * Each GSM mux we have is represented by this structure. If we are
203 * operating as an ldisc then we use this structure as our ldisc
204 * state. We need to sort out lifetimes and locking with respect
205 * to the gsm mux array. For now we don't free DLCI objects that
206 * have been instantiated until the mux itself is terminated.
208 * To consider further: tty open versus mux shutdown.
212 struct tty_struct *tty; /* The tty our ldisc is bound to */
218 /* Events on the GSM channel */
219 wait_queue_head_t event;
221 /* ldisc send work */
222 struct work_struct tx_work;
224 /* Bits for GSM mode decoding */
228 enum gsm_mux_state state;
230 unsigned int address;
236 u8 *txframe; /* TX framing buffer */
238 /* Method for the receiver side */
239 void (*receive)(struct gsm_mux *gsm, u8 ch);
244 int initiator; /* Did we initiate connection */
245 bool dead; /* Has the mux been shut down */
246 struct gsm_dlci *dlci[NUM_DLCI];
247 int old_c_iflag; /* termios c_iflag value before attach */
248 bool constipated; /* Asked by remote to shut up */
249 bool has_devices; /* Devices were registered */
251 struct mutex tx_mutex;
252 unsigned int tx_bytes; /* TX data outstanding */
253 #define TX_THRESH_HI 8192
254 #define TX_THRESH_LO 2048
255 struct list_head tx_ctrl_list; /* Pending control packets */
256 struct list_head tx_data_list; /* Pending data packets */
258 /* Control messages */
259 struct delayed_work kick_timeout; /* Kick TX queuing on timeout */
260 struct timer_list t2_timer; /* Retransmit timer for commands */
261 int cretries; /* Command retry counter */
262 struct gsm_control *pending_cmd;/* Our current pending command */
263 spinlock_t control_lock; /* Protects the pending command */
266 int adaption; /* 1 or 2 supported */
267 u8 ftype; /* UI or UIH */
268 int t1, t2; /* Timers in 1/100th of a sec */
269 int n2; /* Retry count */
271 /* Statistics (not currently exposed) */
272 unsigned long bad_fcs;
273 unsigned long malformed;
274 unsigned long io_error;
275 unsigned long bad_size;
276 unsigned long unsupported;
281 * Mux objects - needed so that we can translate a tty index into the
282 * relevant mux and DLCI.
285 #define MAX_MUX 4 /* 256 minors */
286 static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */
287 static DEFINE_SPINLOCK(gsm_mux_lock);
289 static struct tty_driver *gsm_tty_driver;
292 * This section of the driver logic implements the GSM encodings
293 * both the basic and the 'advanced'. Reliable transport is not
301 /* I is special: the rest are ..*/
312 /* Channel commands */
314 #define CMD_TEST 0x11
317 #define CMD_FCOFF 0x31
320 #define CMD_FCON 0x51
325 /* Virtual modem bits */
332 #define GSM0_SOF 0xF9
333 #define GSM1_SOF 0x7E
334 #define GSM1_ESCAPE 0x7D
335 #define GSM1_ESCAPE_BITS 0x20
338 #define ISO_IEC_646_MASK 0x7F
340 static const struct tty_port_operations gsm_port_ops;
343 * CRC table for GSM 0710
346 static const u8 gsm_fcs8[256] = {
347 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75,
348 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B,
349 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69,
350 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67,
351 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D,
352 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43,
353 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51,
354 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F,
355 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05,
356 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B,
357 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19,
358 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17,
359 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D,
360 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33,
361 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21,
362 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F,
363 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95,
364 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B,
365 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89,
366 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87,
367 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD,
368 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3,
369 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1,
370 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF,
371 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5,
372 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB,
373 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9,
374 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7,
375 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD,
376 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3,
377 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1,
378 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF
381 #define INIT_FCS 0xFF
382 #define GOOD_FCS 0xCF
384 static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len);
385 static int gsm_modem_update(struct gsm_dlci *dlci, u8 brk);
386 static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
388 static int gsm_send_packet(struct gsm_mux *gsm, struct gsm_msg *msg);
389 static void gsmld_write_trigger(struct gsm_mux *gsm);
390 static void gsmld_write_task(struct work_struct *work);
393 * gsm_fcs_add - update FCS
397 * Update the FCS to include c. Uses the algorithm in the specification
401 static inline u8 gsm_fcs_add(u8 fcs, u8 c)
403 return gsm_fcs8[fcs ^ c];
407 * gsm_fcs_add_block - update FCS for a block
410 * @len: length of buffer
412 * Update the FCS to include c. Uses the algorithm in the specification
416 static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len)
419 fcs = gsm_fcs8[fcs ^ *c++];
424 * gsm_read_ea - read a byte into an EA
425 * @val: variable holding value
426 * @c: byte going into the EA
428 * Processes one byte of an EA. Updates the passed variable
429 * and returns 1 if the EA is now completely read
432 static int gsm_read_ea(unsigned int *val, u8 c)
434 /* Add the next 7 bits into the value */
437 /* Was this the last byte of the EA 1 = yes*/
442 * gsm_read_ea_val - read a value until EA
443 * @val: variable holding value
444 * @data: buffer of data
445 * @dlen: length of data
447 * Processes an EA value. Updates the passed variable and
448 * returns the processed data length.
450 static unsigned int gsm_read_ea_val(unsigned int *val, const u8 *data, int dlen)
452 unsigned int len = 0;
454 for (; dlen > 0; dlen--) {
456 if (gsm_read_ea(val, *data++))
463 * gsm_encode_modem - encode modem data bits
464 * @dlci: DLCI to encode from
466 * Returns the correct GSM encoded modem status bits (6 bit field) for
467 * the current status of the DLCI and attached tty object
470 static u8 gsm_encode_modem(const struct gsm_dlci *dlci)
473 /* FC is true flow control not modem bits */
476 if (dlci->modem_tx & TIOCM_DTR)
477 modembits |= MDM_RTC;
478 if (dlci->modem_tx & TIOCM_RTS)
479 modembits |= MDM_RTR;
480 if (dlci->modem_tx & TIOCM_RI)
482 if (dlci->modem_tx & TIOCM_CD || dlci->gsm->initiator)
487 static void gsm_hex_dump_bytes(const char *fname, const u8 *data,
493 print_hex_dump(KERN_INFO, "", DUMP_PREFIX_NONE, 16, 1, data, len,
498 prefix = kasprintf(GFP_ATOMIC, "%s: ", fname);
501 print_hex_dump(KERN_INFO, prefix, DUMP_PREFIX_OFFSET, 16, 1, data, len,
507 * gsm_register_devices - register all tty devices for a given mux index
509 * @driver: the tty driver that describes the tty devices
510 * @index: the mux number is used to calculate the minor numbers of the
511 * ttys for this mux and may differ from the position in the
514 static int gsm_register_devices(struct tty_driver *driver, unsigned int index)
520 if (!driver || index >= MAX_MUX)
523 base = index * NUM_DLCI; /* first minor for this index */
524 for (i = 1; i < NUM_DLCI; i++) {
525 /* Don't register device 0 - this is the control channel
526 * and not a usable tty interface
528 dev = tty_register_device(gsm_tty_driver, base + i, NULL);
531 pr_info("%s failed to register device minor %u",
533 for (i--; i >= 1; i--)
534 tty_unregister_device(gsm_tty_driver, base + i);
543 * gsm_unregister_devices - unregister all tty devices for a given mux index
545 * @driver: the tty driver that describes the tty devices
546 * @index: the mux number is used to calculate the minor numbers of the
547 * ttys for this mux and may differ from the position in the
550 static void gsm_unregister_devices(struct tty_driver *driver,
556 if (!driver || index >= MAX_MUX)
559 base = index * NUM_DLCI; /* first minor for this index */
560 for (i = 1; i < NUM_DLCI; i++) {
561 /* Don't unregister device 0 - this is the control
562 * channel and not a usable tty interface
564 tty_unregister_device(gsm_tty_driver, base + i);
569 * gsm_print_packet - display a frame for debug
570 * @hdr: header to print before decode
571 * @addr: address EA from the frame
572 * @cr: C/R bit seen as initiator
573 * @control: control including PF bit
574 * @data: following data bytes
575 * @dlen: length of data
577 * Displays a packet in human readable format for debugging purposes. The
578 * style is based on amateur radio LAP-B dump display.
581 static void gsm_print_packet(const char *hdr, int addr, int cr,
582 u8 control, const u8 *data, int dlen)
587 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]);
589 switch (control & ~PF) {
609 if (!(control & 0x01)) {
610 pr_cont("I N(S)%d N(R)%d",
611 (control & 0x0E) >> 1, (control & 0xE0) >> 5);
612 } else switch (control & 0x0F) {
614 pr_cont("RR(%d)", (control & 0xE0) >> 5);
617 pr_cont("RNR(%d)", (control & 0xE0) >> 5);
620 pr_cont("REJ(%d)", (control & 0xE0) >> 5);
623 pr_cont("[%02X]", control);
632 gsm_hex_dump_bytes(NULL, data, dlen);
637 * Link level transmission side
641 * gsm_stuff_frame - bytestuff a packet
642 * @input: input buffer
643 * @output: output buffer
644 * @len: length of input
646 * Expand a buffer by bytestuffing it. The worst case size change
647 * is doubling and the caller is responsible for handing out
648 * suitable sized buffers.
651 static int gsm_stuff_frame(const u8 *input, u8 *output, int len)
655 if (*input == GSM1_SOF || *input == GSM1_ESCAPE
656 || (*input & ISO_IEC_646_MASK) == XON
657 || (*input & ISO_IEC_646_MASK) == XOFF) {
658 *output++ = GSM1_ESCAPE;
659 *output++ = *input++ ^ GSM1_ESCAPE_BITS;
662 *output++ = *input++;
669 * gsm_send - send a control frame
671 * @addr: address for control frame
672 * @cr: command/response bit seen as initiator
673 * @control: control byte including PF bit
675 * Format up and transmit a control frame. These should be transmitted
676 * ahead of data when they are needed.
678 static int gsm_send(struct gsm_mux *gsm, int addr, int cr, int control)
684 msg = gsm_data_alloc(gsm, addr, 0, control);
688 /* toggle C/R coding if not initiator */
689 ocr = cr ^ (gsm->initiator ? 0 : 1);
693 *dp++ = (addr << 2) | (ocr << 1) | EA;
696 if (gsm->encoding == 0)
697 *dp++ = EA; /* Length of data = 0 */
699 *dp = 0xFF - gsm_fcs_add_block(INIT_FCS, msg->data, dp - msg->data);
700 msg->len = (dp - msg->data) + 1;
702 gsm_print_packet("Q->", addr, cr, control, NULL, 0);
704 mutex_lock(&gsm->tx_mutex);
705 list_add_tail(&msg->list, &gsm->tx_ctrl_list);
706 gsm->tx_bytes += msg->len;
707 mutex_unlock(&gsm->tx_mutex);
708 gsmld_write_trigger(gsm);
714 * gsm_dlci_clear_queues - remove outstanding data for a DLCI
716 * @dlci: clear for this DLCI
718 * Clears the data queues for a given DLCI.
720 static void gsm_dlci_clear_queues(struct gsm_mux *gsm, struct gsm_dlci *dlci)
722 struct gsm_msg *msg, *nmsg;
723 int addr = dlci->addr;
726 /* Clear DLCI write fifo first */
727 spin_lock_irqsave(&dlci->lock, flags);
728 kfifo_reset(&dlci->fifo);
729 spin_unlock_irqrestore(&dlci->lock, flags);
731 /* Clear data packets in MUX write queue */
732 mutex_lock(&gsm->tx_mutex);
733 list_for_each_entry_safe(msg, nmsg, &gsm->tx_data_list, list) {
734 if (msg->addr != addr)
736 gsm->tx_bytes -= msg->len;
737 list_del(&msg->list);
740 mutex_unlock(&gsm->tx_mutex);
744 * gsm_response - send a control response
746 * @addr: address for control frame
747 * @control: control byte including PF bit
749 * Format up and transmit a link level response frame.
752 static inline void gsm_response(struct gsm_mux *gsm, int addr, int control)
754 gsm_send(gsm, addr, 0, control);
758 * gsm_command - send a control command
760 * @addr: address for control frame
761 * @control: control byte including PF bit
763 * Format up and transmit a link level command frame.
766 static inline void gsm_command(struct gsm_mux *gsm, int addr, int control)
768 gsm_send(gsm, addr, 1, control);
771 /* Data transmission */
773 #define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */
776 * gsm_data_alloc - allocate data frame
778 * @addr: DLCI address
779 * @len: length excluding header and FCS
780 * @ctrl: control byte
782 * Allocate a new data buffer for sending frames with data. Space is left
783 * at the front for header bytes but that is treated as an implementation
784 * detail and not for the high level code to use
787 static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
790 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN,
794 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */
798 INIT_LIST_HEAD(&m->list);
803 * gsm_send_packet - sends a single packet
805 * @msg: packet to send
807 * The given packet is encoded and sent out. No memory is freed.
808 * The caller must hold the gsm tx lock.
810 static int gsm_send_packet(struct gsm_mux *gsm, struct gsm_msg *msg)
815 if (gsm->encoding == 0) {
816 gsm->txframe[0] = GSM0_SOF;
817 memcpy(gsm->txframe + 1, msg->data, msg->len);
818 gsm->txframe[msg->len + 1] = GSM0_SOF;
821 gsm->txframe[0] = GSM1_SOF;
822 len = gsm_stuff_frame(msg->data, gsm->txframe + 1, msg->len);
823 gsm->txframe[len + 1] = GSM1_SOF;
828 gsm_hex_dump_bytes(__func__, gsm->txframe, len);
829 gsm_print_packet("-->", msg->addr, gsm->initiator, msg->ctrl, msg->data,
832 ret = gsmld_output(gsm, gsm->txframe, len);
835 /* FIXME: Can eliminate one SOF in many more cases */
836 gsm->tx_bytes -= msg->len;
842 * gsm_is_flow_ctrl_msg - checks if flow control message
843 * @msg: message to check
845 * Returns true if the given message is a flow control command of the
846 * control channel. False is returned in any other case.
848 static bool gsm_is_flow_ctrl_msg(struct gsm_msg *msg)
855 switch (msg->ctrl & ~PF) {
859 if (gsm_read_ea_val(&cmd, msg->data + 2, msg->len - 2) < 1)
873 * gsm_data_kick - poke the queue
876 * The tty device has called us to indicate that room has appeared in
877 * the transmit queue. Ram more data into the pipe if we have any.
878 * If we have been flow-stopped by a CMD_FCOFF, then we can only
879 * send messages on DLCI0 until CMD_FCON. The caller must hold
882 static int gsm_data_kick(struct gsm_mux *gsm)
884 struct gsm_msg *msg, *nmsg;
885 struct gsm_dlci *dlci;
888 clear_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
890 /* Serialize control messages and control channel messages first */
891 list_for_each_entry_safe(msg, nmsg, &gsm->tx_ctrl_list, list) {
892 if (gsm->constipated && !gsm_is_flow_ctrl_msg(msg))
894 ret = gsm_send_packet(gsm, msg);
900 gsm->tx_bytes -= msg->len;
901 list_del(&msg->list);
906 list_del(&msg->list);
913 if (gsm->constipated)
916 /* Serialize other channels */
917 if (list_empty(&gsm->tx_data_list))
919 list_for_each_entry_safe(msg, nmsg, &gsm->tx_data_list, list) {
920 dlci = gsm->dlci[msg->addr];
921 /* Send only messages for DLCIs with valid state */
922 if (dlci->state != DLCI_OPEN) {
923 gsm->tx_bytes -= msg->len;
924 list_del(&msg->list);
928 ret = gsm_send_packet(gsm, msg);
934 gsm->tx_bytes -= msg->len;
935 list_del(&msg->list);
940 list_del(&msg->list);
951 * __gsm_data_queue - queue a UI or UIH frame
952 * @dlci: DLCI sending the data
953 * @msg: message queued
955 * Add data to the transmit queue and try and get stuff moving
956 * out of the mux tty if not already doing so. The Caller must hold
960 static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
962 struct gsm_mux *gsm = dlci->gsm;
964 u8 *fcs = dp + msg->len;
966 /* Fill in the header */
967 if (gsm->encoding == 0) {
969 *--dp = (msg->len << 1) | EA;
971 *--dp = (msg->len >> 7); /* bits 7 - 15 */
972 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */
978 *--dp = (msg->addr << 2) | CR | EA;
980 *--dp = (msg->addr << 2) | EA;
981 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp);
982 /* Ugly protocol layering violation */
983 if (msg->ctrl == UI || msg->ctrl == (UI|PF))
984 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len);
987 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl,
988 msg->data, msg->len);
990 /* Move the header back and adjust the length, also allow for the FCS
991 now tacked on the end */
992 msg->len += (msg->data - dp) + 1;
995 /* Add to the actual output queue */
996 switch (msg->ctrl & ~PF) {
1000 list_add_tail(&msg->list, &gsm->tx_data_list);
1005 list_add_tail(&msg->list, &gsm->tx_ctrl_list);
1008 gsm->tx_bytes += msg->len;
1010 gsmld_write_trigger(gsm);
1011 schedule_delayed_work(&gsm->kick_timeout, 10 * gsm->t1 * HZ / 100);
1015 * gsm_data_queue - queue a UI or UIH frame
1016 * @dlci: DLCI sending the data
1017 * @msg: message queued
1019 * Add data to the transmit queue and try and get stuff moving
1020 * out of the mux tty if not already doing so. Take the
1021 * the gsm tx lock and dlci lock.
1024 static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
1026 mutex_lock(&dlci->gsm->tx_mutex);
1027 __gsm_data_queue(dlci, msg);
1028 mutex_unlock(&dlci->gsm->tx_mutex);
1032 * gsm_dlci_data_output - try and push data out of a DLCI
1034 * @dlci: the DLCI to pull data from
1036 * Pull data from a DLCI and send it into the transmit queue if there
1037 * is data. Keep to the MRU of the mux. This path handles the usual tty
1038 * interface which is a byte stream with optional modem data.
1040 * Caller must hold the tx_mutex of the mux.
1043 static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci)
1045 struct gsm_msg *msg;
1049 /* for modem bits without break data */
1050 h = ((dlci->adaption == 1) ? 0 : 1);
1052 len = kfifo_len(&dlci->fifo);
1056 /* MTU/MRU count only the data bits but watch adaption mode */
1057 if ((len + h) > gsm->mtu)
1062 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
1066 switch (dlci->adaption) {
1067 case 1: /* Unstructured */
1069 case 2: /* Unstructured with modem bits.
1070 * Always one byte as we never send inline break data
1072 *dp++ = (gsm_encode_modem(dlci) << 1) | EA;
1075 pr_err("%s: unsupported adaption %d\n", __func__,
1080 WARN_ON(len != kfifo_out_locked(&dlci->fifo, dp, len,
1083 /* Notify upper layer about available send space. */
1084 tty_port_tty_wakeup(&dlci->port);
1086 __gsm_data_queue(dlci, msg);
1087 /* Bytes of data we used up */
1092 * gsm_dlci_data_output_framed - try and push data out of a DLCI
1094 * @dlci: the DLCI to pull data from
1096 * Pull data from a DLCI and send it into the transmit queue if there
1097 * is data. Keep to the MRU of the mux. This path handles framed data
1098 * queued as skbuffs to the DLCI.
1100 * Caller must hold the tx_mutex of the mux.
1103 static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
1104 struct gsm_dlci *dlci)
1106 struct gsm_msg *msg;
1109 int last = 0, first = 0;
1112 /* One byte per frame is used for B/F flags */
1113 if (dlci->adaption == 4)
1116 /* dlci->skb is locked by tx_mutex */
1117 if (dlci->skb == NULL) {
1118 dlci->skb = skb_dequeue_tail(&dlci->skb_list);
1119 if (dlci->skb == NULL)
1123 len = dlci->skb->len + overhead;
1125 /* MTU/MRU count only the data bits */
1126 if (len > gsm->mtu) {
1127 if (dlci->adaption == 3) {
1128 /* Over long frame, bin it */
1129 dev_kfree_skb_any(dlci->skb);
1137 size = len + overhead;
1138 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
1140 skb_queue_tail(&dlci->skb_list, dlci->skb);
1146 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */
1147 /* Flag byte to carry the start/end info */
1148 *dp++ = last << 7 | first << 6 | 1; /* EA */
1151 memcpy(dp, dlci->skb->data, len);
1152 skb_pull(dlci->skb, len);
1153 __gsm_data_queue(dlci, msg);
1155 dev_kfree_skb_any(dlci->skb);
1162 * gsm_dlci_modem_output - try and push modem status out of a DLCI
1164 * @dlci: the DLCI to pull modem status from
1165 * @brk: break signal
1167 * Push an empty frame in to the transmit queue to update the modem status
1168 * bits and to transmit an optional break.
1170 * Caller must hold the tx_mutex of the mux.
1173 static int gsm_dlci_modem_output(struct gsm_mux *gsm, struct gsm_dlci *dlci,
1177 struct gsm_msg *msg;
1180 /* for modem bits without break data */
1181 switch (dlci->adaption) {
1182 case 1: /* Unstructured */
1184 case 2: /* Unstructured with modem bits. */
1190 pr_err("%s: unsupported adaption %d\n", __func__,
1195 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
1197 pr_err("%s: gsm_data_alloc error", __func__);
1201 switch (dlci->adaption) {
1202 case 1: /* Unstructured */
1204 case 2: /* Unstructured with modem bits. */
1206 *dp++ = (gsm_encode_modem(dlci) << 1) | EA;
1208 *dp++ = gsm_encode_modem(dlci) << 1;
1209 *dp++ = (brk << 4) | 2 | EA; /* Length, Break, EA */
1217 __gsm_data_queue(dlci, msg);
1222 * gsm_dlci_data_sweep - look for data to send
1225 * Sweep the GSM mux channels in priority order looking for ones with
1226 * data to send. We could do with optimising this scan a bit. We aim
1227 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit
1228 * TX_THRESH_LO we get called again
1230 * FIXME: We should round robin between groups and in theory you can
1231 * renegotiate DLCI priorities with optional stuff. Needs optimising.
1234 static int gsm_dlci_data_sweep(struct gsm_mux *gsm)
1236 /* Priority ordering: We should do priority with RR of the groups */
1237 int i, len, ret = 0;
1239 struct gsm_dlci *dlci;
1241 while (gsm->tx_bytes < TX_THRESH_HI) {
1242 for (sent = false, i = 1; i < NUM_DLCI; i++) {
1243 dlci = gsm->dlci[i];
1244 /* skip unused or blocked channel */
1245 if (!dlci || dlci->constipated)
1247 /* skip channels with invalid state */
1248 if (dlci->state != DLCI_OPEN)
1250 /* count the sent data per adaption */
1251 if (dlci->adaption < 3 && !dlci->net)
1252 len = gsm_dlci_data_output(gsm, dlci);
1254 len = gsm_dlci_data_output_framed(gsm, dlci);
1261 /* The lower DLCs can starve the higher DLCs! */
1274 * gsm_dlci_data_kick - transmit if possible
1275 * @dlci: DLCI to kick
1277 * Transmit data from this DLCI if the queue is empty. We can't rely on
1278 * a tty wakeup except when we filled the pipe so we need to fire off
1279 * new data ourselves in other cases.
1282 static void gsm_dlci_data_kick(struct gsm_dlci *dlci)
1286 if (dlci->constipated)
1289 mutex_lock(&dlci->gsm->tx_mutex);
1290 /* If we have nothing running then we need to fire up */
1291 sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO);
1292 if (dlci->gsm->tx_bytes == 0) {
1294 gsm_dlci_data_output_framed(dlci->gsm, dlci);
1296 gsm_dlci_data_output(dlci->gsm, dlci);
1299 gsm_dlci_data_sweep(dlci->gsm);
1300 mutex_unlock(&dlci->gsm->tx_mutex);
1304 * Control message processing
1309 * gsm_control_reply - send a response frame to a control
1311 * @cmd: the command to use
1312 * @data: data to follow encoded info
1313 * @dlen: length of data
1315 * Encode up and queue a UI/UIH frame containing our response.
1318 static void gsm_control_reply(struct gsm_mux *gsm, int cmd, const u8 *data,
1321 struct gsm_msg *msg;
1322 msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype);
1325 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */
1326 msg->data[1] = (dlen << 1) | EA;
1327 memcpy(msg->data + 2, data, dlen);
1328 gsm_data_queue(gsm->dlci[0], msg);
1332 * gsm_process_modem - process received modem status
1333 * @tty: virtual tty bound to the DLCI
1334 * @dlci: DLCI to affect
1335 * @modem: modem bits (full EA)
1336 * @slen: number of signal octets
1338 * Used when a modem control message or line state inline in adaption
1339 * layer 2 is processed. Sort out the local modem state and throttles
1342 static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
1343 u32 modem, int slen)
1349 /* The modem status command can either contain one octet (V.24 signals)
1350 * or two octets (V.24 signals + break signals). This is specified in
1351 * section 5.4.6.3.7 of the 07.10 mux spec.
1355 modem = modem & 0x7f;
1358 modem = (modem >> 7) & 0x7f;
1361 /* Flow control/ready to communicate */
1362 fc = (modem & MDM_FC) || !(modem & MDM_RTR);
1363 if (fc && !dlci->constipated) {
1364 /* Need to throttle our output on this device */
1365 dlci->constipated = true;
1366 } else if (!fc && dlci->constipated) {
1367 dlci->constipated = false;
1368 gsm_dlci_data_kick(dlci);
1371 /* Map modem bits */
1372 if (modem & MDM_RTC)
1373 mlines |= TIOCM_DSR | TIOCM_DTR;
1374 if (modem & MDM_RTR)
1375 mlines |= TIOCM_RTS | TIOCM_CTS;
1381 /* Carrier drop -> hangup */
1383 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD))
1388 tty_insert_flip_char(&dlci->port, 0, TTY_BREAK);
1389 dlci->modem_rx = mlines;
1393 * gsm_control_modem - modem status received
1395 * @data: data following command
1396 * @clen: command length
1398 * We have received a modem status control message. This is used by
1399 * the GSM mux protocol to pass virtual modem line status and optionally
1400 * to indicate break signals. Unpack it, convert to Linux representation
1401 * and if need be stuff a break message down the tty.
1404 static void gsm_control_modem(struct gsm_mux *gsm, const u8 *data, int clen)
1406 unsigned int addr = 0;
1407 unsigned int modem = 0;
1408 struct gsm_dlci *dlci;
1411 const u8 *dp = data;
1412 struct tty_struct *tty;
1414 while (gsm_read_ea(&addr, *dp++) == 0) {
1419 /* Must be at least one byte following the EA */
1425 /* Closed port, or invalid ? */
1426 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1428 dlci = gsm->dlci[addr];
1431 while (gsm_read_ea(&modem, *dp++) == 0) {
1437 tty = tty_port_tty_get(&dlci->port);
1438 gsm_process_modem(tty, dlci, modem, slen - len);
1443 gsm_control_reply(gsm, CMD_MSC, data, clen);
1447 * gsm_control_rls - remote line status
1450 * @clen: data length
1452 * The modem sends us a two byte message on the control channel whenever
1453 * it wishes to send us an error state from the virtual link. Stuff
1454 * this into the uplink tty if present
1457 static void gsm_control_rls(struct gsm_mux *gsm, const u8 *data, int clen)
1459 struct tty_port *port;
1460 unsigned int addr = 0;
1463 const u8 *dp = data;
1465 while (gsm_read_ea(&addr, *dp++) == 0) {
1470 /* Must be at least one byte following ea */
1475 /* Closed port, or invalid ? */
1476 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1480 if ((bits & 1) == 0)
1483 port = &gsm->dlci[addr]->port;
1486 tty_insert_flip_char(port, 0, TTY_OVERRUN);
1488 tty_insert_flip_char(port, 0, TTY_PARITY);
1490 tty_insert_flip_char(port, 0, TTY_FRAME);
1492 tty_flip_buffer_push(port);
1494 gsm_control_reply(gsm, CMD_RLS, data, clen);
1497 static void gsm_dlci_begin_close(struct gsm_dlci *dlci);
1500 * gsm_control_message - DLCI 0 control processing
1502 * @command: the command EA
1503 * @data: data beyond the command/length EAs
1506 * Input processor for control messages from the other end of the link.
1507 * Processes the incoming request and queues a response frame or an
1508 * NSC response if not supported
1511 static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
1512 const u8 *data, int clen)
1518 struct gsm_dlci *dlci = gsm->dlci[0];
1519 /* Modem wishes to close down */
1523 gsm_dlci_begin_close(dlci);
1528 /* Modem wishes to test, reply with the data */
1529 gsm_control_reply(gsm, CMD_TEST, data, clen);
1532 /* Modem can accept data again */
1533 gsm->constipated = false;
1534 gsm_control_reply(gsm, CMD_FCON, NULL, 0);
1535 /* Kick the link in case it is idling */
1536 gsmld_write_trigger(gsm);
1539 /* Modem wants us to STFU */
1540 gsm->constipated = true;
1541 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0);
1544 /* Out of band modem line change indicator for a DLCI */
1545 gsm_control_modem(gsm, data, clen);
1548 /* Out of band error reception for a DLCI */
1549 gsm_control_rls(gsm, data, clen);
1552 /* Modem wishes to enter power saving state */
1553 gsm_control_reply(gsm, CMD_PSC, NULL, 0);
1555 /* Optional unsupported commands */
1556 case CMD_PN: /* Parameter negotiation */
1557 case CMD_RPN: /* Remote port negotiation */
1558 case CMD_SNC: /* Service negotiation command */
1560 /* Reply to bad commands with an NSC */
1562 gsm_control_reply(gsm, CMD_NSC, buf, 1);
1568 * gsm_control_response - process a response to our control
1570 * @command: the command (response) EA
1571 * @data: data beyond the command/length EA
1574 * Process a response to an outstanding command. We only allow a single
1575 * control message in flight so this is fairly easy. All the clean up
1576 * is done by the caller, we just update the fields, flag it as done
1580 static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
1581 const u8 *data, int clen)
1583 struct gsm_control *ctrl;
1584 unsigned long flags;
1586 spin_lock_irqsave(&gsm->control_lock, flags);
1588 ctrl = gsm->pending_cmd;
1589 /* Does the reply match our command */
1591 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) {
1592 /* Our command was replied to, kill the retry timer */
1593 del_timer(&gsm->t2_timer);
1594 gsm->pending_cmd = NULL;
1595 /* Rejected by the other end */
1596 if (command == CMD_NSC)
1597 ctrl->error = -EOPNOTSUPP;
1599 wake_up(&gsm->event);
1601 spin_unlock_irqrestore(&gsm->control_lock, flags);
1605 * gsm_control_transmit - send control packet
1607 * @ctrl: frame to send
1609 * Send out a pending control command (called under control lock)
1612 static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl)
1614 struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 2, gsm->ftype);
1617 msg->data[0] = (ctrl->cmd << 1) | CR | EA; /* command */
1618 msg->data[1] = (ctrl->len << 1) | EA;
1619 memcpy(msg->data + 2, ctrl->data, ctrl->len);
1620 gsm_data_queue(gsm->dlci[0], msg);
1624 * gsm_control_retransmit - retransmit a control frame
1625 * @t: timer contained in our gsm object
1627 * Called off the T2 timer expiry in order to retransmit control frames
1628 * that have been lost in the system somewhere. The control_lock protects
1629 * us from colliding with another sender or a receive completion event.
1630 * In that situation the timer may still occur in a small window but
1631 * gsm->pending_cmd will be NULL and we just let the timer expire.
1634 static void gsm_control_retransmit(struct timer_list *t)
1636 struct gsm_mux *gsm = from_timer(gsm, t, t2_timer);
1637 struct gsm_control *ctrl;
1638 unsigned long flags;
1639 spin_lock_irqsave(&gsm->control_lock, flags);
1640 ctrl = gsm->pending_cmd;
1642 if (gsm->cretries == 0 || !gsm->dlci[0] || gsm->dlci[0]->dead) {
1643 gsm->pending_cmd = NULL;
1644 ctrl->error = -ETIMEDOUT;
1646 spin_unlock_irqrestore(&gsm->control_lock, flags);
1647 wake_up(&gsm->event);
1651 gsm_control_transmit(gsm, ctrl);
1652 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1654 spin_unlock_irqrestore(&gsm->control_lock, flags);
1658 * gsm_control_send - send a control frame on DLCI 0
1659 * @gsm: the GSM channel
1660 * @command: command to send including CR bit
1661 * @data: bytes of data (must be kmalloced)
1662 * @clen: length of the block to send
1664 * Queue and dispatch a control command. Only one command can be
1665 * active at a time. In theory more can be outstanding but the matching
1666 * gets really complicated so for now stick to one outstanding.
1669 static struct gsm_control *gsm_control_send(struct gsm_mux *gsm,
1670 unsigned int command, u8 *data, int clen)
1672 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control),
1674 unsigned long flags;
1678 wait_event(gsm->event, gsm->pending_cmd == NULL);
1679 spin_lock_irqsave(&gsm->control_lock, flags);
1680 if (gsm->pending_cmd != NULL) {
1681 spin_unlock_irqrestore(&gsm->control_lock, flags);
1684 ctrl->cmd = command;
1687 gsm->pending_cmd = ctrl;
1689 /* If DLCI0 is in ADM mode skip retries, it won't respond */
1690 if (gsm->dlci[0]->mode == DLCI_MODE_ADM)
1693 gsm->cretries = gsm->n2;
1695 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1696 gsm_control_transmit(gsm, ctrl);
1697 spin_unlock_irqrestore(&gsm->control_lock, flags);
1702 * gsm_control_wait - wait for a control to finish
1704 * @control: control we are waiting on
1706 * Waits for the control to complete or time out. Frees any used
1707 * resources and returns 0 for success, or an error if the remote
1708 * rejected or ignored the request.
1711 static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
1714 wait_event(gsm->event, control->done == 1);
1715 err = control->error;
1722 * DLCI level handling: Needs krefs
1726 * State transitions and timers
1730 * gsm_dlci_close - a DLCI has closed
1731 * @dlci: DLCI that closed
1733 * Perform processing when moving a DLCI into closed state. If there
1734 * is an attached tty this is hung up
1737 static void gsm_dlci_close(struct gsm_dlci *dlci)
1739 del_timer(&dlci->t1);
1741 pr_debug("DLCI %d goes closed.\n", dlci->addr);
1742 dlci->state = DLCI_CLOSED;
1743 /* Prevent us from sending data before the link is up again */
1744 dlci->constipated = true;
1745 if (dlci->addr != 0) {
1746 tty_port_tty_hangup(&dlci->port, false);
1747 gsm_dlci_clear_queues(dlci->gsm, dlci);
1748 /* Ensure that gsmtty_open() can return. */
1749 tty_port_set_initialized(&dlci->port, 0);
1750 wake_up_interruptible(&dlci->port.open_wait);
1752 dlci->gsm->dead = true;
1753 /* A DLCI 0 close is a MUX termination so we need to kick that
1754 back to userspace somehow */
1755 gsm_dlci_data_kick(dlci);
1756 wake_up(&dlci->gsm->event);
1760 * gsm_dlci_open - a DLCI has opened
1761 * @dlci: DLCI that opened
1763 * Perform processing when moving a DLCI into open state.
1766 static void gsm_dlci_open(struct gsm_dlci *dlci)
1768 /* Note that SABM UA .. SABM UA first UA lost can mean that we go
1770 del_timer(&dlci->t1);
1771 /* This will let a tty open continue */
1772 dlci->state = DLCI_OPEN;
1773 dlci->constipated = false;
1775 pr_debug("DLCI %d goes open.\n", dlci->addr);
1776 /* Send current modem state */
1778 gsm_modem_update(dlci, 0);
1779 gsm_dlci_data_kick(dlci);
1780 wake_up(&dlci->gsm->event);
1784 * gsm_dlci_t1 - T1 timer expiry
1785 * @t: timer contained in the DLCI that opened
1787 * The T1 timer handles retransmits of control frames (essentially of
1788 * SABM and DISC). We resend the command until the retry count runs out
1789 * in which case an opening port goes back to closed and a closing port
1790 * is simply put into closed state (any further frames from the other
1791 * end will get a DM response)
1793 * Some control dlci can stay in ADM mode with other dlci working just
1794 * fine. In that case we can just keep the control dlci open after the
1795 * DLCI_OPENING retries time out.
1798 static void gsm_dlci_t1(struct timer_list *t)
1800 struct gsm_dlci *dlci = from_timer(dlci, t, t1);
1801 struct gsm_mux *gsm = dlci->gsm;
1803 switch (dlci->state) {
1805 if (dlci->retries) {
1807 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1808 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1809 } else if (!dlci->addr && gsm->control == (DM | PF)) {
1811 pr_info("DLCI %d opening in ADM mode.\n",
1813 dlci->mode = DLCI_MODE_ADM;
1814 gsm_dlci_open(dlci);
1816 gsm_dlci_begin_close(dlci); /* prevent half open link */
1821 if (dlci->retries) {
1823 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1824 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1826 gsm_dlci_close(dlci);
1829 pr_debug("%s: unhandled state: %d\n", __func__, dlci->state);
1835 * gsm_dlci_begin_open - start channel open procedure
1836 * @dlci: DLCI to open
1838 * Commence opening a DLCI from the Linux side. We issue SABM messages
1839 * to the modem which should then reply with a UA or ADM, at which point
1840 * we will move into open state. Opening is done asynchronously with retry
1841 * running off timers and the responses.
1844 static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
1846 struct gsm_mux *gsm = dlci->gsm;
1847 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING)
1849 dlci->retries = gsm->n2;
1850 dlci->state = DLCI_OPENING;
1851 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1852 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1856 * gsm_dlci_set_opening - change state to opening
1857 * @dlci: DLCI to open
1859 * Change internal state to wait for DLCI open from initiator side.
1860 * We set off timers and responses upon reception of an SABM.
1862 static void gsm_dlci_set_opening(struct gsm_dlci *dlci)
1864 switch (dlci->state) {
1867 dlci->state = DLCI_OPENING;
1875 * gsm_dlci_begin_close - start channel open procedure
1876 * @dlci: DLCI to open
1878 * Commence closing a DLCI from the Linux side. We issue DISC messages
1879 * to the modem which should then reply with a UA, at which point we
1880 * will move into closed state. Closing is done asynchronously with retry
1881 * off timers. We may also receive a DM reply from the other end which
1882 * indicates the channel was already closed.
1885 static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
1887 struct gsm_mux *gsm = dlci->gsm;
1888 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
1890 dlci->retries = gsm->n2;
1891 dlci->state = DLCI_CLOSING;
1892 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1893 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1897 * gsm_dlci_data - data arrived
1899 * @data: block of bytes received
1900 * @clen: length of received block
1902 * A UI or UIH frame has arrived which contains data for a channel
1903 * other than the control channel. If the relevant virtual tty is
1904 * open we shovel the bits down it, if not we drop them.
1907 static void gsm_dlci_data(struct gsm_dlci *dlci, const u8 *data, int clen)
1910 struct tty_port *port = &dlci->port;
1911 struct tty_struct *tty;
1912 unsigned int modem = 0;
1917 pr_debug("%d bytes for tty\n", len);
1918 switch (dlci->adaption) {
1919 /* Unsupported types */
1920 case 4: /* Packetised interruptible data */
1922 case 3: /* Packetised uininterruptible voice/data */
1924 case 2: /* Asynchronous serial with line state in each frame */
1925 while (gsm_read_ea(&modem, *data++) == 0) {
1933 tty = tty_port_tty_get(port);
1935 gsm_process_modem(tty, dlci, modem, slen);
1940 case 1: /* Line state will go via DLCI 0 controls only */
1942 tty_insert_flip_string(port, data, len);
1943 tty_flip_buffer_push(port);
1948 * gsm_dlci_command - data arrived on control channel
1950 * @data: block of bytes received
1951 * @len: length of received block
1953 * A UI or UIH frame has arrived which contains data for DLCI 0 the
1954 * control channel. This should contain a command EA followed by
1955 * control data bytes. The command EA contains a command/response bit
1956 * and we divide up the work accordingly.
1959 static void gsm_dlci_command(struct gsm_dlci *dlci, const u8 *data, int len)
1961 /* See what command is involved */
1962 unsigned int command = 0;
1964 if (gsm_read_ea(&command, *data++) == 1) {
1967 /* FIXME: this is properly an EA */
1969 /* Malformed command ? */
1973 gsm_control_message(dlci->gsm, command,
1976 gsm_control_response(dlci->gsm, command,
1984 * gsm_kick_timeout - transmit if possible
1985 * @work: work contained in our gsm object
1987 * Transmit data from DLCIs if the queue is empty. We can't rely on
1988 * a tty wakeup except when we filled the pipe so we need to fire off
1989 * new data ourselves in other cases.
1991 static void gsm_kick_timeout(struct work_struct *work)
1993 struct gsm_mux *gsm = container_of(work, struct gsm_mux, kick_timeout.work);
1996 mutex_lock(&gsm->tx_mutex);
1997 /* If we have nothing running then we need to fire up */
1998 if (gsm->tx_bytes < TX_THRESH_LO)
1999 sent = gsm_dlci_data_sweep(gsm);
2000 mutex_unlock(&gsm->tx_mutex);
2002 if (sent && debug & 4)
2003 pr_info("%s TX queue stalled\n", __func__);
2007 * Allocate/Free DLCI channels
2011 * gsm_dlci_alloc - allocate a DLCI
2013 * @addr: address of the DLCI
2015 * Allocate and install a new DLCI object into the GSM mux.
2017 * FIXME: review locking races
2020 static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
2022 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC);
2025 spin_lock_init(&dlci->lock);
2026 mutex_init(&dlci->mutex);
2027 if (kfifo_alloc(&dlci->fifo, TX_SIZE, GFP_KERNEL) < 0) {
2032 skb_queue_head_init(&dlci->skb_list);
2033 timer_setup(&dlci->t1, gsm_dlci_t1, 0);
2034 tty_port_init(&dlci->port);
2035 dlci->port.ops = &gsm_port_ops;
2038 dlci->adaption = gsm->adaption;
2039 dlci->state = DLCI_CLOSED;
2041 dlci->data = gsm_dlci_data;
2042 /* Prevent us from sending data before the link is up */
2043 dlci->constipated = true;
2045 dlci->data = gsm_dlci_command;
2047 gsm->dlci[addr] = dlci;
2052 * gsm_dlci_free - free DLCI
2053 * @port: tty port for DLCI to free
2059 static void gsm_dlci_free(struct tty_port *port)
2061 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2063 del_timer_sync(&dlci->t1);
2064 dlci->gsm->dlci[dlci->addr] = NULL;
2065 kfifo_free(&dlci->fifo);
2066 while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
2067 dev_kfree_skb(dlci->skb);
2071 static inline void dlci_get(struct gsm_dlci *dlci)
2073 tty_port_get(&dlci->port);
2076 static inline void dlci_put(struct gsm_dlci *dlci)
2078 tty_port_put(&dlci->port);
2081 static void gsm_destroy_network(struct gsm_dlci *dlci);
2084 * gsm_dlci_release - release DLCI
2085 * @dlci: DLCI to destroy
2087 * Release a DLCI. Actual free is deferred until either
2088 * mux is closed or tty is closed - whichever is last.
2092 static void gsm_dlci_release(struct gsm_dlci *dlci)
2094 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
2096 mutex_lock(&dlci->mutex);
2097 gsm_destroy_network(dlci);
2098 mutex_unlock(&dlci->mutex);
2100 /* We cannot use tty_hangup() because in tty_kref_put() the tty
2101 * driver assumes that the hangup queue is free and reuses it to
2102 * queue release_one_tty() -> NULL pointer panic in
2103 * process_one_work().
2107 tty_port_tty_set(&dlci->port, NULL);
2110 dlci->state = DLCI_CLOSED;
2115 * LAPBish link layer logic
2119 * gsm_queue - a GSM frame is ready to process
2120 * @gsm: pointer to our gsm mux
2122 * At this point in time a frame has arrived and been demangled from
2123 * the line encoding. All the differences between the encodings have
2124 * been handled below us and the frame is unpacked into the structures.
2125 * The fcs holds the header FCS but any data FCS must be added here.
2128 static void gsm_queue(struct gsm_mux *gsm)
2130 struct gsm_dlci *dlci;
2134 if (gsm->fcs != GOOD_FCS) {
2137 pr_debug("BAD FCS %02x\n", gsm->fcs);
2140 address = gsm->address >> 1;
2141 if (address >= NUM_DLCI)
2144 cr = gsm->address & 1; /* C/R bit */
2145 cr ^= gsm->initiator ? 0 : 1; /* Flip so 1 always means command */
2147 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
2149 dlci = gsm->dlci[address];
2151 switch (gsm->control) {
2156 dlci = gsm_dlci_alloc(gsm, address);
2160 gsm_response(gsm, address, DM|PF);
2162 gsm_response(gsm, address, UA|PF);
2163 gsm_dlci_open(dlci);
2169 if (dlci == NULL || dlci->state == DLCI_CLOSED) {
2170 gsm_response(gsm, address, DM|PF);
2173 /* Real close complete */
2174 gsm_response(gsm, address, UA|PF);
2175 gsm_dlci_close(dlci);
2178 if (cr == 0 || dlci == NULL)
2180 switch (dlci->state) {
2182 gsm_dlci_close(dlci);
2185 gsm_dlci_open(dlci);
2188 pr_debug("%s: unhandled state: %d\n", __func__,
2193 case DM: /* DM can be valid unsolicited */
2199 gsm_dlci_close(dlci);
2205 if (dlci == NULL || dlci->state != DLCI_OPEN) {
2206 gsm_response(gsm, address, DM|PF);
2209 dlci->data(dlci, gsm->buf, gsm->len);
2222 * gsm0_receive - perform processing for non-transparency
2223 * @gsm: gsm data for this ldisc instance
2226 * Receive bytes in gsm mode 0
2229 static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
2233 switch (gsm->state) {
2234 case GSM_SEARCH: /* SOF marker */
2235 if (c == GSM0_SOF) {
2236 gsm->state = GSM_ADDRESS;
2239 gsm->fcs = INIT_FCS;
2242 case GSM_ADDRESS: /* Address EA */
2243 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2244 if (gsm_read_ea(&gsm->address, c))
2245 gsm->state = GSM_CONTROL;
2247 case GSM_CONTROL: /* Control Byte */
2248 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2250 gsm->state = GSM_LEN0;
2252 case GSM_LEN0: /* Length EA */
2253 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2254 if (gsm_read_ea(&gsm->len, c)) {
2255 if (gsm->len > gsm->mru) {
2257 gsm->state = GSM_SEARCH;
2262 gsm->state = GSM_FCS;
2264 gsm->state = GSM_DATA;
2267 gsm->state = GSM_LEN1;
2270 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2272 gsm->len |= len << 7;
2273 if (gsm->len > gsm->mru) {
2275 gsm->state = GSM_SEARCH;
2280 gsm->state = GSM_FCS;
2282 gsm->state = GSM_DATA;
2284 case GSM_DATA: /* Data */
2285 gsm->buf[gsm->count++] = c;
2286 if (gsm->count == gsm->len) {
2287 /* Calculate final FCS for UI frames over all data */
2288 if ((gsm->control & ~PF) != UIH) {
2289 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf,
2292 gsm->state = GSM_FCS;
2295 case GSM_FCS: /* FCS follows the packet */
2296 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2297 gsm->state = GSM_SSOF;
2300 gsm->state = GSM_SEARCH;
2307 pr_debug("%s: unhandled state: %d\n", __func__, gsm->state);
2313 * gsm1_receive - perform processing for non-transparency
2314 * @gsm: gsm data for this ldisc instance
2317 * Receive bytes in mode 1 (Advanced option)
2320 static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
2322 /* handle XON/XOFF */
2323 if ((c & ISO_IEC_646_MASK) == XON) {
2324 gsm->constipated = true;
2326 } else if ((c & ISO_IEC_646_MASK) == XOFF) {
2327 gsm->constipated = false;
2328 /* Kick the link in case it is idling */
2329 gsmld_write_trigger(gsm);
2332 if (c == GSM1_SOF) {
2333 /* EOF is only valid in frame if we have got to the data state */
2334 if (gsm->state == GSM_DATA) {
2335 if (gsm->count < 1) {
2338 gsm->state = GSM_START;
2341 /* Remove the FCS from data */
2343 if ((gsm->control & ~PF) != UIH) {
2344 /* Calculate final FCS for UI frames over all
2347 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf,
2350 /* Add the FCS itself to test against GOOD_FCS */
2351 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
2352 gsm->len = gsm->count;
2354 gsm->state = GSM_START;
2357 /* Any partial frame was a runt so go back to start */
2358 if (gsm->state != GSM_START) {
2359 if (gsm->state != GSM_SEARCH)
2361 gsm->state = GSM_START;
2363 /* A SOF in GSM_START means we are still reading idling or
2368 if (c == GSM1_ESCAPE) {
2373 /* Only an unescaped SOF gets us out of GSM search */
2374 if (gsm->state == GSM_SEARCH)
2378 c ^= GSM1_ESCAPE_BITS;
2379 gsm->escape = false;
2381 switch (gsm->state) {
2382 case GSM_START: /* First byte after SOF */
2384 gsm->state = GSM_ADDRESS;
2385 gsm->fcs = INIT_FCS;
2387 case GSM_ADDRESS: /* Address continuation */
2388 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2389 if (gsm_read_ea(&gsm->address, c))
2390 gsm->state = GSM_CONTROL;
2392 case GSM_CONTROL: /* Control Byte */
2393 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2396 gsm->state = GSM_DATA;
2398 case GSM_DATA: /* Data */
2399 if (gsm->count > gsm->mru) { /* Allow one for the FCS */
2400 gsm->state = GSM_OVERRUN;
2403 gsm->buf[gsm->count++] = c;
2405 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */
2408 pr_debug("%s: unhandled state: %d\n", __func__, gsm->state);
2414 * gsm_error - handle tty error
2417 * Handle an error in the receipt of data for a frame. Currently we just
2418 * go back to hunting for a SOF.
2420 * FIXME: better diagnostics ?
2423 static void gsm_error(struct gsm_mux *gsm)
2425 gsm->state = GSM_SEARCH;
2430 * gsm_cleanup_mux - generic GSM protocol cleanup
2432 * @disc: disconnect link?
2434 * Clean up the bits of the mux which are the same for all framing
2435 * protocols. Remove the mux from the mux table, stop all the timers
2436 * and then shut down each device hanging up the channels as we go.
2439 static void gsm_cleanup_mux(struct gsm_mux *gsm, bool disc)
2442 struct gsm_dlci *dlci = gsm->dlci[0];
2443 struct gsm_msg *txq, *ntxq;
2446 mutex_lock(&gsm->mutex);
2449 if (disc && dlci->state != DLCI_CLOSED) {
2450 gsm_dlci_begin_close(dlci);
2451 wait_event(gsm->event, dlci->state == DLCI_CLOSED);
2456 /* Finish outstanding timers, making sure they are done */
2457 cancel_delayed_work_sync(&gsm->kick_timeout);
2458 del_timer_sync(&gsm->t2_timer);
2460 /* Finish writing to ldisc */
2461 flush_work(&gsm->tx_work);
2463 /* Free up any link layer users and finally the control channel */
2464 if (gsm->has_devices) {
2465 gsm_unregister_devices(gsm_tty_driver, gsm->num);
2466 gsm->has_devices = false;
2468 for (i = NUM_DLCI - 1; i >= 0; i--)
2470 gsm_dlci_release(gsm->dlci[i]);
2471 mutex_unlock(&gsm->mutex);
2472 /* Now wipe the queues */
2473 tty_ldisc_flush(gsm->tty);
2474 list_for_each_entry_safe(txq, ntxq, &gsm->tx_ctrl_list, list)
2476 INIT_LIST_HEAD(&gsm->tx_ctrl_list);
2477 list_for_each_entry_safe(txq, ntxq, &gsm->tx_data_list, list)
2479 INIT_LIST_HEAD(&gsm->tx_data_list);
2483 * gsm_activate_mux - generic GSM setup
2486 * Set up the bits of the mux which are the same for all framing
2487 * protocols. Add the mux to the mux table so it can be opened and
2488 * finally kick off connecting to DLCI 0 on the modem.
2491 static int gsm_activate_mux(struct gsm_mux *gsm)
2493 struct gsm_dlci *dlci;
2496 dlci = gsm_dlci_alloc(gsm, 0);
2500 if (gsm->encoding == 0)
2501 gsm->receive = gsm0_receive;
2503 gsm->receive = gsm1_receive;
2505 ret = gsm_register_devices(gsm_tty_driver, gsm->num);
2509 gsm->has_devices = true;
2510 gsm->dead = false; /* Tty opens are now permissible */
2515 * gsm_free_mux - free up a mux
2518 * Dispose of allocated resources for a dead mux
2520 static void gsm_free_mux(struct gsm_mux *gsm)
2524 for (i = 0; i < MAX_MUX; i++) {
2525 if (gsm == gsm_mux[i]) {
2530 mutex_destroy(&gsm->tx_mutex);
2531 mutex_destroy(&gsm->mutex);
2532 kfree(gsm->txframe);
2538 * gsm_free_muxr - free up a mux
2539 * @ref: kreference to the mux to free
2541 * Dispose of allocated resources for a dead mux
2543 static void gsm_free_muxr(struct kref *ref)
2545 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref);
2549 static inline void mux_get(struct gsm_mux *gsm)
2551 unsigned long flags;
2553 spin_lock_irqsave(&gsm_mux_lock, flags);
2554 kref_get(&gsm->ref);
2555 spin_unlock_irqrestore(&gsm_mux_lock, flags);
2558 static inline void mux_put(struct gsm_mux *gsm)
2560 unsigned long flags;
2562 spin_lock_irqsave(&gsm_mux_lock, flags);
2563 kref_put(&gsm->ref, gsm_free_muxr);
2564 spin_unlock_irqrestore(&gsm_mux_lock, flags);
2567 static inline unsigned int mux_num_to_base(struct gsm_mux *gsm)
2569 return gsm->num * NUM_DLCI;
2572 static inline unsigned int mux_line_to_num(unsigned int line)
2574 return line / NUM_DLCI;
2578 * gsm_alloc_mux - allocate a mux
2580 * Creates a new mux ready for activation.
2583 static struct gsm_mux *gsm_alloc_mux(void)
2586 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
2589 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL);
2590 if (gsm->buf == NULL) {
2594 gsm->txframe = kmalloc(2 * (MAX_MTU + PROT_OVERHEAD - 1), GFP_KERNEL);
2595 if (gsm->txframe == NULL) {
2600 spin_lock_init(&gsm->lock);
2601 mutex_init(&gsm->mutex);
2602 mutex_init(&gsm->tx_mutex);
2603 kref_init(&gsm->ref);
2604 INIT_LIST_HEAD(&gsm->tx_ctrl_list);
2605 INIT_LIST_HEAD(&gsm->tx_data_list);
2606 INIT_DELAYED_WORK(&gsm->kick_timeout, gsm_kick_timeout);
2607 timer_setup(&gsm->t2_timer, gsm_control_retransmit, 0);
2608 INIT_WORK(&gsm->tx_work, gsmld_write_task);
2609 init_waitqueue_head(&gsm->event);
2610 spin_lock_init(&gsm->control_lock);
2618 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
2620 gsm->dead = true; /* Avoid early tty opens */
2622 /* Store the instance to the mux array or abort if no space is
2625 spin_lock(&gsm_mux_lock);
2626 for (i = 0; i < MAX_MUX; i++) {
2633 spin_unlock(&gsm_mux_lock);
2635 mutex_destroy(&gsm->tx_mutex);
2636 mutex_destroy(&gsm->mutex);
2637 kfree(gsm->txframe);
2646 static void gsm_copy_config_values(struct gsm_mux *gsm,
2647 struct gsm_config *c)
2649 memset(c, 0, sizeof(*c));
2650 c->adaption = gsm->adaption;
2651 c->encapsulation = gsm->encoding;
2652 c->initiator = gsm->initiator;
2655 c->t3 = 0; /* Not supported */
2657 if (gsm->ftype == UIH)
2661 pr_debug("Ftype %d i %d\n", gsm->ftype, c->i);
2667 static int gsm_config(struct gsm_mux *gsm, struct gsm_config *c)
2671 int need_restart = 0;
2673 /* Stuff we don't support yet - UI or I frame transport, windowing */
2674 if ((c->adaption != 1 && c->adaption != 2) || c->k)
2676 /* Check the MRU/MTU range looks sane */
2677 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8)
2681 if (c->encapsulation > 1) /* Basic, advanced, no I */
2683 if (c->initiator > 1)
2685 if (c->i == 0 || c->i > 2) /* UIH and UI only */
2688 * See what is needed for reconfiguration
2692 if (c->t1 != 0 && c->t1 != gsm->t1)
2694 if (c->t2 != 0 && c->t2 != gsm->t2)
2696 if (c->encapsulation != gsm->encoding)
2698 if (c->adaption != gsm->adaption)
2701 if (c->initiator != gsm->initiator)
2703 if (c->mru != gsm->mru)
2705 if (c->mtu != gsm->mtu)
2709 * Close down what is needed, restart and initiate the new
2710 * configuration. On the first time there is no DLCI[0]
2711 * and closing or cleaning up is not necessary.
2713 if (need_close || need_restart)
2714 gsm_cleanup_mux(gsm, true);
2716 gsm->initiator = c->initiator;
2719 gsm->encoding = c->encapsulation;
2720 gsm->adaption = c->adaption;
2734 * FIXME: We need to separate activation/deactivation from adding
2735 * and removing from the mux array
2738 ret = gsm_activate_mux(gsm);
2742 gsm_dlci_begin_open(gsm->dlci[0]);
2748 * gsmld_output - write to link
2750 * @data: bytes to output
2753 * Write a block of data from the GSM mux to the data channel. This
2754 * will eventually be serialized from above but at the moment isn't.
2757 static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
2759 if (tty_write_room(gsm->tty) < len) {
2760 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
2764 gsm_hex_dump_bytes(__func__, data, len);
2765 return gsm->tty->ops->write(gsm->tty, data, len);
2770 * gsmld_write_trigger - schedule ldisc write task
2773 static void gsmld_write_trigger(struct gsm_mux *gsm)
2775 if (!gsm || !gsm->dlci[0] || gsm->dlci[0]->dead)
2777 schedule_work(&gsm->tx_work);
2782 * gsmld_write_task - ldisc write task
2783 * @work: our tx write work
2785 * Writes out data to the ldisc if possible. We are doing this here to
2786 * avoid dead-locking. This returns if no space or data is left for output.
2788 static void gsmld_write_task(struct work_struct *work)
2790 struct gsm_mux *gsm = container_of(work, struct gsm_mux, tx_work);
2793 /* All outstanding control channel and control messages and one data
2797 mutex_lock(&gsm->tx_mutex);
2799 ret = gsm_data_kick(gsm);
2800 mutex_unlock(&gsm->tx_mutex);
2803 for (i = 0; i < NUM_DLCI; i++)
2805 tty_port_tty_wakeup(&gsm->dlci[i]->port);
2809 * gsmld_attach_gsm - mode set up
2810 * @tty: our tty structure
2813 * Set up the MUX for basic mode and commence connecting to the
2814 * modem. Currently called from the line discipline set up but
2815 * will need moving to an ioctl path.
2818 static void gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2820 gsm->tty = tty_kref_get(tty);
2821 /* Turn off tty XON/XOFF handling to handle it explicitly. */
2822 gsm->old_c_iflag = tty->termios.c_iflag;
2823 tty->termios.c_iflag &= (IXON | IXOFF);
2827 * gsmld_detach_gsm - stop doing 0710 mux
2828 * @tty: tty attached to the mux
2831 * Shutdown and then clean up the resources used by the line discipline
2834 static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2836 WARN_ON(tty != gsm->tty);
2837 /* Restore tty XON/XOFF handling. */
2838 gsm->tty->termios.c_iflag = gsm->old_c_iflag;
2839 tty_kref_put(gsm->tty);
2843 static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
2844 const char *fp, int count)
2846 struct gsm_mux *gsm = tty->disc_data;
2847 char flags = TTY_NORMAL;
2850 gsm_hex_dump_bytes(__func__, cp, count);
2852 for (; count; count--, cp++) {
2858 gsm->receive(gsm, *cp);
2867 WARN_ONCE(1, "%s: unknown flag %d\n",
2868 tty_name(tty), flags);
2872 /* FASYNC if needed ? */
2873 /* If clogged call tty_throttle(tty); */
2877 * gsmld_flush_buffer - clean input queue
2878 * @tty: terminal device
2880 * Flush the input buffer. Called when the line discipline is
2881 * being closed, when the tty layer wants the buffer flushed (eg
2885 static void gsmld_flush_buffer(struct tty_struct *tty)
2890 * gsmld_close - close the ldisc for this tty
2893 * Called from the terminal layer when this line discipline is
2894 * being shut down, either because of a close or becsuse of a
2895 * discipline change. The function will not be called while other
2896 * ldisc methods are in progress.
2899 static void gsmld_close(struct tty_struct *tty)
2901 struct gsm_mux *gsm = tty->disc_data;
2903 /* The ldisc locks and closes the port before calling our close. This
2904 * means we have no way to do a proper disconnect. We will not bother
2907 gsm_cleanup_mux(gsm, false);
2909 gsmld_detach_gsm(tty, gsm);
2911 gsmld_flush_buffer(tty);
2912 /* Do other clean up here */
2917 * gsmld_open - open an ldisc
2918 * @tty: terminal to open
2920 * Called when this line discipline is being attached to the
2921 * terminal device. Can sleep. Called serialized so that no
2922 * other events will occur in parallel. No further open will occur
2926 static int gsmld_open(struct tty_struct *tty)
2928 struct gsm_mux *gsm;
2930 if (tty->ops->write == NULL)
2933 /* Attach our ldisc data */
2934 gsm = gsm_alloc_mux();
2938 tty->disc_data = gsm;
2939 tty->receive_room = 65536;
2941 /* Attach the initial passive connection */
2944 gsmld_attach_gsm(tty, gsm);
2950 * gsmld_write_wakeup - asynchronous I/O notifier
2953 * Required for the ptys, serial driver etc. since processes
2954 * that attach themselves to the master and rely on ASYNC
2955 * IO must be woken up
2958 static void gsmld_write_wakeup(struct tty_struct *tty)
2960 struct gsm_mux *gsm = tty->disc_data;
2963 gsmld_write_trigger(gsm);
2967 * gsmld_read - read function for tty
2969 * @file: file object
2970 * @buf: userspace buffer pointer
2975 * Perform reads for the line discipline. We are guaranteed that the
2976 * line discipline will not be closed under us but we may get multiple
2977 * parallel readers and must handle this ourselves. We may also get
2978 * a hangup. Always called in user context, may sleep.
2980 * This code must be sure never to sleep through a hangup.
2983 static ssize_t gsmld_read(struct tty_struct *tty, struct file *file,
2984 unsigned char *buf, size_t nr,
2985 void **cookie, unsigned long offset)
2991 * gsmld_write - write function for tty
2993 * @file: file object
2994 * @buf: userspace buffer pointer
2997 * Called when the owner of the device wants to send a frame
2998 * itself (or some other control data). The data is transferred
2999 * as-is and must be properly framed and checksummed as appropriate
3000 * by userspace. Frames are either sent whole or not at all as this
3001 * avoids pain user side.
3004 static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
3005 const unsigned char *buf, size_t nr)
3007 struct gsm_mux *gsm = tty->disc_data;
3015 mutex_lock(&gsm->tx_mutex);
3016 space = tty_write_room(tty);
3018 ret = tty->ops->write(tty, buf, nr);
3020 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
3021 mutex_unlock(&gsm->tx_mutex);
3027 * gsmld_poll - poll method for N_GSM0710
3028 * @tty: terminal device
3029 * @file: file accessing it
3032 * Called when the line discipline is asked to poll() for data or
3033 * for special events. This code is not serialized with respect to
3034 * other events save open/close.
3036 * This code must be sure never to sleep through a hangup.
3037 * Called without the kernel lock held - fine
3040 static __poll_t gsmld_poll(struct tty_struct *tty, struct file *file,
3044 struct gsm_mux *gsm = tty->disc_data;
3046 poll_wait(file, &tty->read_wait, wait);
3047 poll_wait(file, &tty->write_wait, wait);
3051 if (tty_hung_up_p(file))
3053 if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
3055 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
3056 mask |= EPOLLOUT | EPOLLWRNORM;
3060 static int gsmld_ioctl(struct tty_struct *tty, unsigned int cmd,
3063 struct gsm_config c;
3064 struct gsm_mux *gsm = tty->disc_data;
3068 case GSMIOC_GETCONF:
3069 gsm_copy_config_values(gsm, &c);
3070 if (copy_to_user((void __user *)arg, &c, sizeof(c)))
3073 case GSMIOC_SETCONF:
3074 if (copy_from_user(&c, (void __user *)arg, sizeof(c)))
3076 return gsm_config(gsm, &c);
3077 case GSMIOC_GETFIRST:
3078 base = mux_num_to_base(gsm);
3079 return put_user(base + 1, (__u32 __user *)arg);
3081 return n_tty_ioctl_helper(tty, cmd, arg);
3090 static int gsm_mux_net_open(struct net_device *net)
3092 pr_debug("%s called\n", __func__);
3093 netif_start_queue(net);
3097 static int gsm_mux_net_close(struct net_device *net)
3099 netif_stop_queue(net);
3103 static void dlci_net_free(struct gsm_dlci *dlci)
3109 dlci->adaption = dlci->prev_adaption;
3110 dlci->data = dlci->prev_data;
3111 free_netdev(dlci->net);
3114 static void net_free(struct kref *ref)
3116 struct gsm_mux_net *mux_net;
3117 struct gsm_dlci *dlci;
3119 mux_net = container_of(ref, struct gsm_mux_net, ref);
3120 dlci = mux_net->dlci;
3123 unregister_netdev(dlci->net);
3124 dlci_net_free(dlci);
3128 static inline void muxnet_get(struct gsm_mux_net *mux_net)
3130 kref_get(&mux_net->ref);
3133 static inline void muxnet_put(struct gsm_mux_net *mux_net)
3135 kref_put(&mux_net->ref, net_free);
3138 static netdev_tx_t gsm_mux_net_start_xmit(struct sk_buff *skb,
3139 struct net_device *net)
3141 struct gsm_mux_net *mux_net = netdev_priv(net);
3142 struct gsm_dlci *dlci = mux_net->dlci;
3143 muxnet_get(mux_net);
3145 skb_queue_head(&dlci->skb_list, skb);
3146 net->stats.tx_packets++;
3147 net->stats.tx_bytes += skb->len;
3148 gsm_dlci_data_kick(dlci);
3149 /* And tell the kernel when the last transmit started. */
3150 netif_trans_update(net);
3151 muxnet_put(mux_net);
3152 return NETDEV_TX_OK;
3155 /* called when a packet did not ack after watchdogtimeout */
3156 static void gsm_mux_net_tx_timeout(struct net_device *net, unsigned int txqueue)
3158 /* Tell syslog we are hosed. */
3159 dev_dbg(&net->dev, "Tx timed out.\n");
3161 /* Update statistics */
3162 net->stats.tx_errors++;
3165 static void gsm_mux_rx_netchar(struct gsm_dlci *dlci,
3166 const unsigned char *in_buf, int size)
3168 struct net_device *net = dlci->net;
3169 struct sk_buff *skb;
3170 struct gsm_mux_net *mux_net = netdev_priv(net);
3171 muxnet_get(mux_net);
3173 /* Allocate an sk_buff */
3174 skb = dev_alloc_skb(size + NET_IP_ALIGN);
3176 /* We got no receive buffer. */
3177 net->stats.rx_dropped++;
3178 muxnet_put(mux_net);
3181 skb_reserve(skb, NET_IP_ALIGN);
3182 skb_put_data(skb, in_buf, size);
3185 skb->protocol = htons(ETH_P_IP);
3187 /* Ship it off to the kernel */
3190 /* update out statistics */
3191 net->stats.rx_packets++;
3192 net->stats.rx_bytes += size;
3193 muxnet_put(mux_net);
3197 static void gsm_mux_net_init(struct net_device *net)
3199 static const struct net_device_ops gsm_netdev_ops = {
3200 .ndo_open = gsm_mux_net_open,
3201 .ndo_stop = gsm_mux_net_close,
3202 .ndo_start_xmit = gsm_mux_net_start_xmit,
3203 .ndo_tx_timeout = gsm_mux_net_tx_timeout,
3206 net->netdev_ops = &gsm_netdev_ops;
3208 /* fill in the other fields */
3209 net->watchdog_timeo = GSM_NET_TX_TIMEOUT;
3210 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
3211 net->type = ARPHRD_NONE;
3212 net->tx_queue_len = 10;
3216 /* caller holds the dlci mutex */
3217 static void gsm_destroy_network(struct gsm_dlci *dlci)
3219 struct gsm_mux_net *mux_net;
3221 pr_debug("destroy network interface\n");
3224 mux_net = netdev_priv(dlci->net);
3225 muxnet_put(mux_net);
3229 /* caller holds the dlci mutex */
3230 static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
3234 struct net_device *net;
3235 struct gsm_mux_net *mux_net;
3237 if (!capable(CAP_NET_ADMIN))
3240 /* Already in a non tty mode */
3241 if (dlci->adaption > 2)
3244 if (nc->protocol != htons(ETH_P_IP))
3245 return -EPROTONOSUPPORT;
3247 if (nc->adaption != 3 && nc->adaption != 4)
3248 return -EPROTONOSUPPORT;
3250 pr_debug("create network interface\n");
3253 if (nc->if_name[0] != '\0')
3254 netname = nc->if_name;
3255 net = alloc_netdev(sizeof(struct gsm_mux_net), netname,
3256 NET_NAME_UNKNOWN, gsm_mux_net_init);
3258 pr_err("alloc_netdev failed\n");
3261 net->mtu = dlci->gsm->mtu;
3263 net->max_mtu = dlci->gsm->mtu;
3264 mux_net = netdev_priv(net);
3265 mux_net->dlci = dlci;
3266 kref_init(&mux_net->ref);
3267 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */
3269 /* reconfigure dlci for network */
3270 dlci->prev_adaption = dlci->adaption;
3271 dlci->prev_data = dlci->data;
3272 dlci->adaption = nc->adaption;
3273 dlci->data = gsm_mux_rx_netchar;
3276 pr_debug("register netdev\n");
3277 retval = register_netdev(net);
3279 pr_err("network register fail %d\n", retval);
3280 dlci_net_free(dlci);
3283 return net->ifindex; /* return network index */
3286 /* Line discipline for real tty */
3287 static struct tty_ldisc_ops tty_ldisc_packet = {
3288 .owner = THIS_MODULE,
3292 .close = gsmld_close,
3293 .flush_buffer = gsmld_flush_buffer,
3295 .write = gsmld_write,
3296 .ioctl = gsmld_ioctl,
3298 .receive_buf = gsmld_receive_buf,
3299 .write_wakeup = gsmld_write_wakeup
3307 * gsm_modem_upd_via_data - send modem bits via convergence layer
3309 * @brk: break signal
3311 * Send an empty frame to signal mobile state changes and to transmit the
3312 * break signal for adaption 2.
3315 static void gsm_modem_upd_via_data(struct gsm_dlci *dlci, u8 brk)
3317 struct gsm_mux *gsm = dlci->gsm;
3319 if (dlci->state != DLCI_OPEN || dlci->adaption != 2)
3322 mutex_lock(&gsm->tx_mutex);
3323 gsm_dlci_modem_output(gsm, dlci, brk);
3324 mutex_unlock(&gsm->tx_mutex);
3328 * gsm_modem_upd_via_msc - send modem bits via control frame
3330 * @brk: break signal
3333 static int gsm_modem_upd_via_msc(struct gsm_dlci *dlci, u8 brk)
3336 struct gsm_control *ctrl;
3339 if (dlci->gsm->encoding != 0)
3342 modembits[0] = (dlci->addr << 2) | 2 | EA; /* DLCI, Valid, EA */
3344 modembits[1] = (gsm_encode_modem(dlci) << 1) | EA;
3346 modembits[1] = gsm_encode_modem(dlci) << 1;
3347 modembits[2] = (brk << 4) | 2 | EA; /* Length, Break, EA */
3350 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len);
3353 return gsm_control_wait(dlci->gsm, ctrl);
3357 * gsm_modem_update - send modem status line state
3359 * @brk: break signal
3362 static int gsm_modem_update(struct gsm_dlci *dlci, u8 brk)
3364 if (dlci->adaption == 2) {
3365 /* Send convergence layer type 2 empty data frame. */
3366 gsm_modem_upd_via_data(dlci, brk);
3368 } else if (dlci->gsm->encoding == 0) {
3369 /* Send as MSC control message. */
3370 return gsm_modem_upd_via_msc(dlci, brk);
3373 /* Modem status lines are not supported. */
3374 return -EPROTONOSUPPORT;
3377 static int gsm_carrier_raised(struct tty_port *port)
3379 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
3380 struct gsm_mux *gsm = dlci->gsm;
3382 /* Not yet open so no carrier info */
3383 if (dlci->state != DLCI_OPEN)
3389 * Basic mode with control channel in ADM mode may not respond
3390 * to CMD_MSC at all and modem_rx is empty.
3392 if (gsm->encoding == 0 && gsm->dlci[0]->mode == DLCI_MODE_ADM &&
3396 return dlci->modem_rx & TIOCM_CD;
3399 static void gsm_dtr_rts(struct tty_port *port, int onoff)
3401 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
3402 unsigned int modem_tx = dlci->modem_tx;
3404 modem_tx |= TIOCM_DTR | TIOCM_RTS;
3406 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
3407 if (modem_tx != dlci->modem_tx) {
3408 dlci->modem_tx = modem_tx;
3409 gsm_modem_update(dlci, 0);
3413 static const struct tty_port_operations gsm_port_ops = {
3414 .carrier_raised = gsm_carrier_raised,
3415 .dtr_rts = gsm_dtr_rts,
3416 .destruct = gsm_dlci_free,
3419 static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty)
3421 struct gsm_mux *gsm;
3422 struct gsm_dlci *dlci;
3423 unsigned int line = tty->index;
3424 unsigned int mux = mux_line_to_num(line);
3432 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
3433 if (gsm_mux[mux] == NULL)
3435 if (line == 0 || line > 61) /* 62/63 reserved */
3440 /* If DLCI 0 is not yet fully open return an error.
3441 This is ok from a locking
3442 perspective as we don't have to worry about this
3444 mutex_lock(&gsm->mutex);
3445 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN) {
3446 mutex_unlock(&gsm->mutex);
3449 dlci = gsm->dlci[line];
3452 dlci = gsm_dlci_alloc(gsm, line);
3455 mutex_unlock(&gsm->mutex);
3458 ret = tty_port_install(&dlci->port, driver, tty);
3462 mutex_unlock(&gsm->mutex);
3467 dlci_get(gsm->dlci[0]);
3469 tty->driver_data = dlci;
3470 mutex_unlock(&gsm->mutex);
3475 static int gsmtty_open(struct tty_struct *tty, struct file *filp)
3477 struct gsm_dlci *dlci = tty->driver_data;
3478 struct tty_port *port = &dlci->port;
3479 struct gsm_mux *gsm = dlci->gsm;
3482 tty_port_tty_set(port, tty);
3485 /* We could in theory open and close before we wait - eg if we get
3486 a DM straight back. This is ok as that will have caused a hangup */
3487 tty_port_set_initialized(port, 1);
3488 /* Start sending off SABM messages */
3490 gsm_dlci_begin_open(dlci);
3492 gsm_dlci_set_opening(dlci);
3493 /* And wait for virtual carrier */
3494 return tty_port_block_til_ready(port, tty, filp);
3497 static void gsmtty_close(struct tty_struct *tty, struct file *filp)
3499 struct gsm_dlci *dlci = tty->driver_data;
3503 if (dlci->state == DLCI_CLOSED)
3505 mutex_lock(&dlci->mutex);
3506 gsm_destroy_network(dlci);
3507 mutex_unlock(&dlci->mutex);
3508 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
3510 gsm_dlci_begin_close(dlci);
3511 if (tty_port_initialized(&dlci->port) && C_HUPCL(tty))
3512 tty_port_lower_dtr_rts(&dlci->port);
3513 tty_port_close_end(&dlci->port, tty);
3514 tty_port_tty_set(&dlci->port, NULL);
3518 static void gsmtty_hangup(struct tty_struct *tty)
3520 struct gsm_dlci *dlci = tty->driver_data;
3521 if (dlci->state == DLCI_CLOSED)
3523 tty_port_hangup(&dlci->port);
3524 gsm_dlci_begin_close(dlci);
3527 static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf,
3531 struct gsm_dlci *dlci = tty->driver_data;
3532 if (dlci->state == DLCI_CLOSED)
3534 /* Stuff the bytes into the fifo queue */
3535 sent = kfifo_in_locked(&dlci->fifo, buf, len, &dlci->lock);
3536 /* Need to kick the channel */
3537 gsm_dlci_data_kick(dlci);
3541 static unsigned int gsmtty_write_room(struct tty_struct *tty)
3543 struct gsm_dlci *dlci = tty->driver_data;
3544 if (dlci->state == DLCI_CLOSED)
3546 return kfifo_avail(&dlci->fifo);
3549 static unsigned int gsmtty_chars_in_buffer(struct tty_struct *tty)
3551 struct gsm_dlci *dlci = tty->driver_data;
3552 if (dlci->state == DLCI_CLOSED)
3554 return kfifo_len(&dlci->fifo);
3557 static void gsmtty_flush_buffer(struct tty_struct *tty)
3559 struct gsm_dlci *dlci = tty->driver_data;
3560 unsigned long flags;
3562 if (dlci->state == DLCI_CLOSED)
3564 /* Caution needed: If we implement reliable transport classes
3565 then the data being transmitted can't simply be junked once
3566 it has first hit the stack. Until then we can just blow it
3568 spin_lock_irqsave(&dlci->lock, flags);
3569 kfifo_reset(&dlci->fifo);
3570 spin_unlock_irqrestore(&dlci->lock, flags);
3571 /* Need to unhook this DLCI from the transmit queue logic */
3574 static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
3576 /* The FIFO handles the queue so the kernel will do the right
3577 thing waiting on chars_in_buffer before calling us. No work
3581 static int gsmtty_tiocmget(struct tty_struct *tty)
3583 struct gsm_dlci *dlci = tty->driver_data;
3584 if (dlci->state == DLCI_CLOSED)
3586 return dlci->modem_rx;
3589 static int gsmtty_tiocmset(struct tty_struct *tty,
3590 unsigned int set, unsigned int clear)
3592 struct gsm_dlci *dlci = tty->driver_data;
3593 unsigned int modem_tx = dlci->modem_tx;
3595 if (dlci->state == DLCI_CLOSED)
3600 if (modem_tx != dlci->modem_tx) {
3601 dlci->modem_tx = modem_tx;
3602 return gsm_modem_update(dlci, 0);
3608 static int gsmtty_ioctl(struct tty_struct *tty,
3609 unsigned int cmd, unsigned long arg)
3611 struct gsm_dlci *dlci = tty->driver_data;
3612 struct gsm_netconfig nc;
3615 if (dlci->state == DLCI_CLOSED)
3618 case GSMIOC_ENABLE_NET:
3619 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc)))
3621 nc.if_name[IFNAMSIZ-1] = '\0';
3622 /* return net interface index or error code */
3623 mutex_lock(&dlci->mutex);
3624 index = gsm_create_network(dlci, &nc);
3625 mutex_unlock(&dlci->mutex);
3626 if (copy_to_user((void __user *)arg, &nc, sizeof(nc)))
3629 case GSMIOC_DISABLE_NET:
3630 if (!capable(CAP_NET_ADMIN))
3632 mutex_lock(&dlci->mutex);
3633 gsm_destroy_network(dlci);
3634 mutex_unlock(&dlci->mutex);
3637 return -ENOIOCTLCMD;
3641 static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old)
3643 struct gsm_dlci *dlci = tty->driver_data;
3644 if (dlci->state == DLCI_CLOSED)
3646 /* For the moment its fixed. In actual fact the speed information
3647 for the virtual channel can be propogated in both directions by
3648 the RPN control message. This however rapidly gets nasty as we
3649 then have to remap modem signals each way according to whether
3650 our virtual cable is null modem etc .. */
3651 tty_termios_copy_hw(&tty->termios, old);
3654 static void gsmtty_throttle(struct tty_struct *tty)
3656 struct gsm_dlci *dlci = tty->driver_data;
3657 if (dlci->state == DLCI_CLOSED)
3660 dlci->modem_tx &= ~TIOCM_RTS;
3661 dlci->throttled = true;
3662 /* Send an MSC with RTS cleared */
3663 gsm_modem_update(dlci, 0);
3666 static void gsmtty_unthrottle(struct tty_struct *tty)
3668 struct gsm_dlci *dlci = tty->driver_data;
3669 if (dlci->state == DLCI_CLOSED)
3672 dlci->modem_tx |= TIOCM_RTS;
3673 dlci->throttled = false;
3674 /* Send an MSC with RTS set */
3675 gsm_modem_update(dlci, 0);
3678 static int gsmtty_break_ctl(struct tty_struct *tty, int state)
3680 struct gsm_dlci *dlci = tty->driver_data;
3681 int encode = 0; /* Off */
3682 if (dlci->state == DLCI_CLOSED)
3685 if (state == -1) /* "On indefinitely" - we can't encode this
3688 else if (state > 0) {
3689 encode = state / 200; /* mS to encoding */
3691 encode = 0x0F; /* Best effort */
3693 return gsm_modem_update(dlci, encode);
3696 static void gsmtty_cleanup(struct tty_struct *tty)
3698 struct gsm_dlci *dlci = tty->driver_data;
3699 struct gsm_mux *gsm = dlci->gsm;
3702 dlci_put(gsm->dlci[0]);
3706 /* Virtual ttys for the demux */
3707 static const struct tty_operations gsmtty_ops = {
3708 .install = gsmtty_install,
3709 .open = gsmtty_open,
3710 .close = gsmtty_close,
3711 .write = gsmtty_write,
3712 .write_room = gsmtty_write_room,
3713 .chars_in_buffer = gsmtty_chars_in_buffer,
3714 .flush_buffer = gsmtty_flush_buffer,
3715 .ioctl = gsmtty_ioctl,
3716 .throttle = gsmtty_throttle,
3717 .unthrottle = gsmtty_unthrottle,
3718 .set_termios = gsmtty_set_termios,
3719 .hangup = gsmtty_hangup,
3720 .wait_until_sent = gsmtty_wait_until_sent,
3721 .tiocmget = gsmtty_tiocmget,
3722 .tiocmset = gsmtty_tiocmset,
3723 .break_ctl = gsmtty_break_ctl,
3724 .cleanup = gsmtty_cleanup,
3729 static int __init gsm_init(void)
3731 /* Fill in our line protocol discipline, and register it */
3732 int status = tty_register_ldisc(&tty_ldisc_packet);
3734 pr_err("n_gsm: can't register line discipline (err = %d)\n",
3739 gsm_tty_driver = tty_alloc_driver(256, TTY_DRIVER_REAL_RAW |
3740 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_HARDWARE_BREAK);
3741 if (IS_ERR(gsm_tty_driver)) {
3742 pr_err("gsm_init: tty allocation failed.\n");
3743 status = PTR_ERR(gsm_tty_driver);
3744 goto err_unreg_ldisc;
3746 gsm_tty_driver->driver_name = "gsmtty";
3747 gsm_tty_driver->name = "gsmtty";
3748 gsm_tty_driver->major = 0; /* Dynamic */
3749 gsm_tty_driver->minor_start = 0;
3750 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
3751 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
3752 gsm_tty_driver->init_termios = tty_std_termios;
3754 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
3755 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
3757 if (tty_register_driver(gsm_tty_driver)) {
3758 pr_err("gsm_init: tty registration failed.\n");
3760 goto err_put_driver;
3762 pr_debug("gsm_init: loaded as %d,%d.\n",
3763 gsm_tty_driver->major, gsm_tty_driver->minor_start);
3766 tty_driver_kref_put(gsm_tty_driver);
3768 tty_unregister_ldisc(&tty_ldisc_packet);
3772 static void __exit gsm_exit(void)
3774 tty_unregister_ldisc(&tty_ldisc_packet);
3775 tty_unregister_driver(gsm_tty_driver);
3776 tty_driver_kref_put(gsm_tty_driver);
3779 module_init(gsm_init);
3780 module_exit(gsm_exit);
3783 MODULE_LICENSE("GPL");
3784 MODULE_ALIAS_LDISC(N_GSM0710);