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 /* Module debug bits */
67 #define DBG_DUMP BIT(0) /* Data transmission dump. */
68 #define DBG_CD_ON BIT(1) /* Always assume CD line on. */
69 #define DBG_DATA BIT(2) /* Data transmission details. */
70 #define DBG_ERRORS BIT(3) /* Details for fail conditions. */
71 #define DBG_TTY BIT(4) /* Transmission statistics for DLCI TTYs. */
72 #define DBG_PAYLOAD BIT(5) /* Limits DBG_DUMP to payload frames. */
74 /* Defaults: these are from the specification */
76 #define T1 10 /* 100mS */
77 #define T2 34 /* 333mS */
78 #define N2 3 /* Retry 3 times */
80 /* Use long timers for testing at low speed with debug on */
87 * Semi-arbitrary buffer size limits. 0710 is normally run with 32-64 byte
88 * limits so this is plenty
92 /* SOF, ADDR, CTRL, LEN1, LEN2, ..., FCS, EOF */
93 #define PROT_OVERHEAD 7
94 #define GSM_NET_TX_TIMEOUT (HZ*10)
97 * struct gsm_mux_net - network interface
99 * Created when net interface is initialized.
103 struct gsm_dlci *dlci;
107 * Each block of data we have queued to go out is in the form of
108 * a gsm_msg which holds everything we need in a link layer independent
113 struct list_head list;
114 u8 addr; /* DLCI address + flags */
115 u8 ctrl; /* Control byte + flags */
116 unsigned int len; /* Length of data block (can be zero) */
117 unsigned char *data; /* Points into buffer but not at the start */
118 unsigned char buffer[];
121 enum gsm_dlci_state {
123 DLCI_OPENING, /* Sending SABM not seen UA */
124 DLCI_OPEN, /* SABM/UA complete */
125 DLCI_CLOSING, /* Sending DISC not seen UA/DM */
129 DLCI_MODE_ABM, /* Normal Asynchronous Balanced Mode */
130 DLCI_MODE_ADM, /* Asynchronous Disconnected Mode */
134 * Each active data link has a gsm_dlci structure associated which ties
135 * the link layer to an optional tty (if the tty side is open). To avoid
136 * complexity right now these are only ever freed up when the mux is
139 * At the moment we don't free DLCI objects until the mux is torn down
140 * this avoid object life time issues but might be worth review later.
146 enum gsm_dlci_state state;
150 enum gsm_dlci_mode mode;
151 spinlock_t lock; /* Protects the internal state */
152 struct timer_list t1; /* Retransmit timer for SABM and UA */
154 /* Uplink tty if active */
155 struct tty_port port; /* The tty bound to this DLCI if there is one */
156 #define TX_SIZE 4096 /* Must be power of 2. */
157 struct kfifo fifo; /* Queue fifo for the DLCI */
158 int adaption; /* Adaption layer in use */
160 u32 modem_rx; /* Our incoming virtual modem lines */
161 u32 modem_tx; /* Our outgoing modem lines */
162 bool dead; /* Refuse re-open */
164 bool throttled; /* Private copy of throttle state */
165 bool constipated; /* Throttle status for outgoing */
167 struct sk_buff *skb; /* Frame being sent */
168 struct sk_buff_head skb_list; /* Queued frames */
169 /* Data handling callback */
170 void (*data)(struct gsm_dlci *dlci, const u8 *data, int len);
171 void (*prev_data)(struct gsm_dlci *dlci, const u8 *data, int len);
172 struct net_device *net; /* network interface, if created */
175 /* Total number of supported devices */
176 #define GSM_TTY_MINORS 256
178 /* DLCI 0, 62/63 are special or reserved see gsmtty_open */
183 * DLCI 0 is used to pass control blocks out of band of the data
184 * flow (and with a higher link priority). One command can be outstanding
185 * at a time and we use this structure to manage them. They are created
186 * and destroyed by the user context, and updated by the receive paths
191 u8 cmd; /* Command we are issuing */
192 u8 *data; /* Data for the command in case we retransmit */
193 int len; /* Length of block for retransmission */
194 int done; /* Done flag */
195 int error; /* Error if any */
218 * Each GSM mux we have is represented by this structure. If we are
219 * operating as an ldisc then we use this structure as our ldisc
220 * state. We need to sort out lifetimes and locking with respect
221 * to the gsm mux array. For now we don't free DLCI objects that
222 * have been instantiated until the mux itself is terminated.
224 * To consider further: tty open versus mux shutdown.
228 struct tty_struct *tty; /* The tty our ldisc is bound to */
234 /* Events on the GSM channel */
235 wait_queue_head_t event;
237 /* ldisc send work */
238 struct work_struct tx_work;
240 /* Bits for GSM mode decoding */
244 enum gsm_mux_state state;
246 unsigned int address;
249 enum gsm_encoding encoding;
252 u8 *txframe; /* TX framing buffer */
254 /* Method for the receiver side */
255 void (*receive)(struct gsm_mux *gsm, u8 ch);
260 int initiator; /* Did we initiate connection */
261 bool dead; /* Has the mux been shut down */
262 struct gsm_dlci *dlci[NUM_DLCI];
263 int old_c_iflag; /* termios c_iflag value before attach */
264 bool constipated; /* Asked by remote to shut up */
265 bool has_devices; /* Devices were registered */
268 unsigned int tx_bytes; /* TX data outstanding */
269 #define TX_THRESH_HI 8192
270 #define TX_THRESH_LO 2048
271 struct list_head tx_ctrl_list; /* Pending control packets */
272 struct list_head tx_data_list; /* Pending data packets */
274 /* Control messages */
275 struct timer_list kick_timer; /* Kick TX queuing on timeout */
276 struct timer_list t2_timer; /* Retransmit timer for commands */
277 int cretries; /* Command retry counter */
278 struct gsm_control *pending_cmd;/* Our current pending command */
279 spinlock_t control_lock; /* Protects the pending command */
282 int adaption; /* 1 or 2 supported */
283 u8 ftype; /* UI or UIH */
284 int t1, t2; /* Timers in 1/100th of a sec */
285 int n2; /* Retry count */
287 /* Statistics (not currently exposed) */
288 unsigned long bad_fcs;
289 unsigned long malformed;
290 unsigned long io_error;
291 unsigned long bad_size;
292 unsigned long unsupported;
297 * Mux objects - needed so that we can translate a tty index into the
298 * relevant mux and DLCI.
301 #define MAX_MUX 4 /* 256 minors */
302 static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */
303 static DEFINE_SPINLOCK(gsm_mux_lock);
305 static struct tty_driver *gsm_tty_driver;
308 * This section of the driver logic implements the GSM encodings
309 * both the basic and the 'advanced'. Reliable transport is not
317 /* I is special: the rest are ..*/
328 /* Channel commands */
330 #define CMD_TEST 0x11
333 #define CMD_FCOFF 0x31
336 #define CMD_FCON 0x51
341 /* Virtual modem bits */
348 #define GSM0_SOF 0xF9
349 #define GSM1_SOF 0x7E
350 #define GSM1_ESCAPE 0x7D
351 #define GSM1_ESCAPE_BITS 0x20
354 #define ISO_IEC_646_MASK 0x7F
356 static const struct tty_port_operations gsm_port_ops;
359 * CRC table for GSM 0710
362 static const u8 gsm_fcs8[256] = {
363 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75,
364 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B,
365 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69,
366 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67,
367 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D,
368 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43,
369 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51,
370 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F,
371 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05,
372 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B,
373 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19,
374 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17,
375 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D,
376 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33,
377 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21,
378 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F,
379 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95,
380 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B,
381 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89,
382 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87,
383 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD,
384 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3,
385 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1,
386 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF,
387 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5,
388 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB,
389 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9,
390 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7,
391 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD,
392 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3,
393 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1,
394 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF
397 #define INIT_FCS 0xFF
398 #define GOOD_FCS 0xCF
400 static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len);
401 static int gsm_modem_update(struct gsm_dlci *dlci, u8 brk);
402 static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
404 static int gsm_send_packet(struct gsm_mux *gsm, struct gsm_msg *msg);
405 static void gsmld_write_trigger(struct gsm_mux *gsm);
406 static void gsmld_write_task(struct work_struct *work);
409 * gsm_fcs_add - update FCS
413 * Update the FCS to include c. Uses the algorithm in the specification
417 static inline u8 gsm_fcs_add(u8 fcs, u8 c)
419 return gsm_fcs8[fcs ^ c];
423 * gsm_fcs_add_block - update FCS for a block
426 * @len: length of buffer
428 * Update the FCS to include c. Uses the algorithm in the specification
432 static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len)
435 fcs = gsm_fcs8[fcs ^ *c++];
440 * gsm_read_ea - read a byte into an EA
441 * @val: variable holding value
442 * @c: byte going into the EA
444 * Processes one byte of an EA. Updates the passed variable
445 * and returns 1 if the EA is now completely read
448 static int gsm_read_ea(unsigned int *val, u8 c)
450 /* Add the next 7 bits into the value */
453 /* Was this the last byte of the EA 1 = yes*/
458 * gsm_read_ea_val - read a value until EA
459 * @val: variable holding value
460 * @data: buffer of data
461 * @dlen: length of data
463 * Processes an EA value. Updates the passed variable and
464 * returns the processed data length.
466 static unsigned int gsm_read_ea_val(unsigned int *val, const u8 *data, int dlen)
468 unsigned int len = 0;
470 for (; dlen > 0; dlen--) {
472 if (gsm_read_ea(val, *data++))
479 * gsm_encode_modem - encode modem data bits
480 * @dlci: DLCI to encode from
482 * Returns the correct GSM encoded modem status bits (6 bit field) for
483 * the current status of the DLCI and attached tty object
486 static u8 gsm_encode_modem(const struct gsm_dlci *dlci)
489 /* FC is true flow control not modem bits */
492 if (dlci->modem_tx & TIOCM_DTR)
493 modembits |= MDM_RTC;
494 if (dlci->modem_tx & TIOCM_RTS)
495 modembits |= MDM_RTR;
496 if (dlci->modem_tx & TIOCM_RI)
498 if (dlci->modem_tx & TIOCM_CD || dlci->gsm->initiator)
503 static void gsm_hex_dump_bytes(const char *fname, const u8 *data,
509 print_hex_dump(KERN_INFO, "", DUMP_PREFIX_NONE, 16, 1, data, len,
514 prefix = kasprintf(GFP_ATOMIC, "%s: ", fname);
517 print_hex_dump(KERN_INFO, prefix, DUMP_PREFIX_OFFSET, 16, 1, data, len,
523 * gsm_register_devices - register all tty devices for a given mux index
525 * @driver: the tty driver that describes the tty devices
526 * @index: the mux number is used to calculate the minor numbers of the
527 * ttys for this mux and may differ from the position in the
530 static int gsm_register_devices(struct tty_driver *driver, unsigned int index)
536 if (!driver || index >= MAX_MUX)
539 base = index * NUM_DLCI; /* first minor for this index */
540 for (i = 1; i < NUM_DLCI; i++) {
541 /* Don't register device 0 - this is the control channel
542 * and not a usable tty interface
544 dev = tty_register_device(gsm_tty_driver, base + i, NULL);
546 if (debug & DBG_ERRORS)
547 pr_info("%s failed to register device minor %u",
549 for (i--; i >= 1; i--)
550 tty_unregister_device(gsm_tty_driver, base + i);
559 * gsm_unregister_devices - unregister all tty devices for a given mux index
561 * @driver: the tty driver that describes the tty devices
562 * @index: the mux number is used to calculate the minor numbers of the
563 * ttys for this mux and may differ from the position in the
566 static void gsm_unregister_devices(struct tty_driver *driver,
572 if (!driver || index >= MAX_MUX)
575 base = index * NUM_DLCI; /* first minor for this index */
576 for (i = 1; i < NUM_DLCI; i++) {
577 /* Don't unregister device 0 - this is the control
578 * channel and not a usable tty interface
580 tty_unregister_device(gsm_tty_driver, base + i);
585 * gsm_print_packet - display a frame for debug
586 * @hdr: header to print before decode
587 * @addr: address EA from the frame
588 * @cr: C/R bit seen as initiator
589 * @control: control including PF bit
590 * @data: following data bytes
591 * @dlen: length of data
593 * Displays a packet in human readable format for debugging purposes. The
594 * style is based on amateur radio LAP-B dump display.
597 static void gsm_print_packet(const char *hdr, int addr, int cr,
598 u8 control, const u8 *data, int dlen)
600 if (!(debug & DBG_DUMP))
602 /* Only show user payload frames if debug & DBG_PAYLOAD */
603 if (!(debug & DBG_PAYLOAD) && addr != 0)
604 if ((control & ~PF) == UI || (control & ~PF) == UIH)
607 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]);
609 switch (control & ~PF) {
629 if (!(control & 0x01)) {
630 pr_cont("I N(S)%d N(R)%d",
631 (control & 0x0E) >> 1, (control & 0xE0) >> 5);
632 } else switch (control & 0x0F) {
634 pr_cont("RR(%d)", (control & 0xE0) >> 5);
637 pr_cont("RNR(%d)", (control & 0xE0) >> 5);
640 pr_cont("REJ(%d)", (control & 0xE0) >> 5);
643 pr_cont("[%02X]", control);
652 gsm_hex_dump_bytes(NULL, data, dlen);
657 * Link level transmission side
661 * gsm_stuff_frame - bytestuff a packet
662 * @input: input buffer
663 * @output: output buffer
664 * @len: length of input
666 * Expand a buffer by bytestuffing it. The worst case size change
667 * is doubling and the caller is responsible for handing out
668 * suitable sized buffers.
671 static int gsm_stuff_frame(const u8 *input, u8 *output, int len)
675 if (*input == GSM1_SOF || *input == GSM1_ESCAPE
676 || (*input & ISO_IEC_646_MASK) == XON
677 || (*input & ISO_IEC_646_MASK) == XOFF) {
678 *output++ = GSM1_ESCAPE;
679 *output++ = *input++ ^ GSM1_ESCAPE_BITS;
682 *output++ = *input++;
689 * gsm_send - send a control frame
691 * @addr: address for control frame
692 * @cr: command/response bit seen as initiator
693 * @control: control byte including PF bit
695 * Format up and transmit a control frame. These should be transmitted
696 * ahead of data when they are needed.
698 static int gsm_send(struct gsm_mux *gsm, int addr, int cr, int control)
705 msg = gsm_data_alloc(gsm, addr, 0, control);
709 /* toggle C/R coding if not initiator */
710 ocr = cr ^ (gsm->initiator ? 0 : 1);
714 *dp++ = (addr << 2) | (ocr << 1) | EA;
717 if (gsm->encoding == GSM_BASIC_OPT)
718 *dp++ = EA; /* Length of data = 0 */
720 *dp = 0xFF - gsm_fcs_add_block(INIT_FCS, msg->data, dp - msg->data);
721 msg->len = (dp - msg->data) + 1;
723 gsm_print_packet("Q->", addr, cr, control, NULL, 0);
725 spin_lock_irqsave(&gsm->tx_lock, flags);
726 list_add_tail(&msg->list, &gsm->tx_ctrl_list);
727 gsm->tx_bytes += msg->len;
728 spin_unlock_irqrestore(&gsm->tx_lock, flags);
729 gsmld_write_trigger(gsm);
735 * gsm_dlci_clear_queues - remove outstanding data for a DLCI
737 * @dlci: clear for this DLCI
739 * Clears the data queues for a given DLCI.
741 static void gsm_dlci_clear_queues(struct gsm_mux *gsm, struct gsm_dlci *dlci)
743 struct gsm_msg *msg, *nmsg;
744 int addr = dlci->addr;
747 /* Clear DLCI write fifo first */
748 spin_lock_irqsave(&dlci->lock, flags);
749 kfifo_reset(&dlci->fifo);
750 spin_unlock_irqrestore(&dlci->lock, flags);
752 /* Clear data packets in MUX write queue */
753 spin_lock_irqsave(&gsm->tx_lock, flags);
754 list_for_each_entry_safe(msg, nmsg, &gsm->tx_data_list, list) {
755 if (msg->addr != addr)
757 gsm->tx_bytes -= msg->len;
758 list_del(&msg->list);
761 spin_unlock_irqrestore(&gsm->tx_lock, flags);
765 * gsm_response - send a control response
767 * @addr: address for control frame
768 * @control: control byte including PF bit
770 * Format up and transmit a link level response frame.
773 static inline void gsm_response(struct gsm_mux *gsm, int addr, int control)
775 gsm_send(gsm, addr, 0, control);
779 * gsm_command - send a control command
781 * @addr: address for control frame
782 * @control: control byte including PF bit
784 * Format up and transmit a link level command frame.
787 static inline void gsm_command(struct gsm_mux *gsm, int addr, int control)
789 gsm_send(gsm, addr, 1, control);
792 /* Data transmission */
794 #define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */
797 * gsm_data_alloc - allocate data frame
799 * @addr: DLCI address
800 * @len: length excluding header and FCS
801 * @ctrl: control byte
803 * Allocate a new data buffer for sending frames with data. Space is left
804 * at the front for header bytes but that is treated as an implementation
805 * detail and not for the high level code to use
808 static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
811 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN,
815 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */
819 INIT_LIST_HEAD(&m->list);
824 * gsm_send_packet - sends a single packet
826 * @msg: packet to send
828 * The given packet is encoded and sent out. No memory is freed.
829 * The caller must hold the gsm tx lock.
831 static int gsm_send_packet(struct gsm_mux *gsm, struct gsm_msg *msg)
836 if (gsm->encoding == GSM_BASIC_OPT) {
837 gsm->txframe[0] = GSM0_SOF;
838 memcpy(gsm->txframe + 1, msg->data, msg->len);
839 gsm->txframe[msg->len + 1] = GSM0_SOF;
842 gsm->txframe[0] = GSM1_SOF;
843 len = gsm_stuff_frame(msg->data, gsm->txframe + 1, msg->len);
844 gsm->txframe[len + 1] = GSM1_SOF;
848 if (debug & DBG_DATA)
849 gsm_hex_dump_bytes(__func__, gsm->txframe, len);
850 gsm_print_packet("-->", msg->addr, gsm->initiator, msg->ctrl, msg->data,
853 ret = gsmld_output(gsm, gsm->txframe, len);
856 /* FIXME: Can eliminate one SOF in many more cases */
857 gsm->tx_bytes -= msg->len;
863 * gsm_is_flow_ctrl_msg - checks if flow control message
864 * @msg: message to check
866 * Returns true if the given message is a flow control command of the
867 * control channel. False is returned in any other case.
869 static bool gsm_is_flow_ctrl_msg(struct gsm_msg *msg)
876 switch (msg->ctrl & ~PF) {
880 if (gsm_read_ea_val(&cmd, msg->data + 2, msg->len - 2) < 1)
894 * gsm_data_kick - poke the queue
897 * The tty device has called us to indicate that room has appeared in
898 * the transmit queue. Ram more data into the pipe if we have any.
899 * If we have been flow-stopped by a CMD_FCOFF, then we can only
900 * send messages on DLCI0 until CMD_FCON. The caller must hold
903 static int gsm_data_kick(struct gsm_mux *gsm)
905 struct gsm_msg *msg, *nmsg;
906 struct gsm_dlci *dlci;
909 clear_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
911 /* Serialize control messages and control channel messages first */
912 list_for_each_entry_safe(msg, nmsg, &gsm->tx_ctrl_list, list) {
913 if (gsm->constipated && !gsm_is_flow_ctrl_msg(msg))
915 ret = gsm_send_packet(gsm, msg);
921 gsm->tx_bytes -= msg->len;
922 list_del(&msg->list);
927 list_del(&msg->list);
934 if (gsm->constipated)
937 /* Serialize other channels */
938 if (list_empty(&gsm->tx_data_list))
940 list_for_each_entry_safe(msg, nmsg, &gsm->tx_data_list, list) {
941 dlci = gsm->dlci[msg->addr];
942 /* Send only messages for DLCIs with valid state */
943 if (dlci->state != DLCI_OPEN) {
944 gsm->tx_bytes -= msg->len;
945 list_del(&msg->list);
949 ret = gsm_send_packet(gsm, msg);
955 gsm->tx_bytes -= msg->len;
956 list_del(&msg->list);
961 list_del(&msg->list);
972 * __gsm_data_queue - queue a UI or UIH frame
973 * @dlci: DLCI sending the data
974 * @msg: message queued
976 * Add data to the transmit queue and try and get stuff moving
977 * out of the mux tty if not already doing so. The Caller must hold
981 static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
983 struct gsm_mux *gsm = dlci->gsm;
985 u8 *fcs = dp + msg->len;
987 /* Fill in the header */
988 if (gsm->encoding == GSM_BASIC_OPT) {
990 *--dp = (msg->len << 1) | EA;
992 *--dp = (msg->len >> 7); /* bits 7 - 15 */
993 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */
999 *--dp = (msg->addr << 2) | CR | EA;
1001 *--dp = (msg->addr << 2) | EA;
1002 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp);
1003 /* Ugly protocol layering violation */
1004 if (msg->ctrl == UI || msg->ctrl == (UI|PF))
1005 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len);
1008 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl,
1009 msg->data, msg->len);
1011 /* Move the header back and adjust the length, also allow for the FCS
1012 now tacked on the end */
1013 msg->len += (msg->data - dp) + 1;
1016 /* Add to the actual output queue */
1017 switch (msg->ctrl & ~PF) {
1020 if (msg->addr > 0) {
1021 list_add_tail(&msg->list, &gsm->tx_data_list);
1026 list_add_tail(&msg->list, &gsm->tx_ctrl_list);
1029 gsm->tx_bytes += msg->len;
1031 gsmld_write_trigger(gsm);
1032 mod_timer(&gsm->kick_timer, jiffies + 10 * gsm->t1 * HZ / 100);
1036 * gsm_data_queue - queue a UI or UIH frame
1037 * @dlci: DLCI sending the data
1038 * @msg: message queued
1040 * Add data to the transmit queue and try and get stuff moving
1041 * out of the mux tty if not already doing so. Take the
1042 * the gsm tx lock and dlci lock.
1045 static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
1047 unsigned long flags;
1048 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
1049 __gsm_data_queue(dlci, msg);
1050 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
1054 * gsm_dlci_data_output - try and push data out of a DLCI
1056 * @dlci: the DLCI to pull data from
1058 * Pull data from a DLCI and send it into the transmit queue if there
1059 * is data. Keep to the MRU of the mux. This path handles the usual tty
1060 * interface which is a byte stream with optional modem data.
1062 * Caller must hold the tx_lock of the mux.
1065 static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci)
1067 struct gsm_msg *msg;
1071 /* for modem bits without break data */
1072 h = ((dlci->adaption == 1) ? 0 : 1);
1074 len = kfifo_len(&dlci->fifo);
1078 /* MTU/MRU count only the data bits but watch adaption mode */
1079 if ((len + h) > gsm->mtu)
1084 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
1088 switch (dlci->adaption) {
1089 case 1: /* Unstructured */
1091 case 2: /* Unstructured with modem bits.
1092 * Always one byte as we never send inline break data
1094 *dp++ = (gsm_encode_modem(dlci) << 1) | EA;
1097 pr_err("%s: unsupported adaption %d\n", __func__,
1102 WARN_ON(len != kfifo_out_locked(&dlci->fifo, dp, len,
1105 /* Notify upper layer about available send space. */
1106 tty_port_tty_wakeup(&dlci->port);
1108 __gsm_data_queue(dlci, msg);
1109 /* Bytes of data we used up */
1114 * gsm_dlci_data_output_framed - try and push data out of a DLCI
1116 * @dlci: the DLCI to pull data from
1118 * Pull data from a DLCI and send it into the transmit queue if there
1119 * is data. Keep to the MRU of the mux. This path handles framed data
1120 * queued as skbuffs to the DLCI.
1122 * Caller must hold the tx_lock of the mux.
1125 static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
1126 struct gsm_dlci *dlci)
1128 struct gsm_msg *msg;
1131 int last = 0, first = 0;
1134 /* One byte per frame is used for B/F flags */
1135 if (dlci->adaption == 4)
1138 /* dlci->skb is locked by tx_lock */
1139 if (dlci->skb == NULL) {
1140 dlci->skb = skb_dequeue_tail(&dlci->skb_list);
1141 if (dlci->skb == NULL)
1145 len = dlci->skb->len + overhead;
1147 /* MTU/MRU count only the data bits */
1148 if (len > gsm->mtu) {
1149 if (dlci->adaption == 3) {
1150 /* Over long frame, bin it */
1151 dev_kfree_skb_any(dlci->skb);
1159 size = len + overhead;
1160 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
1162 skb_queue_tail(&dlci->skb_list, dlci->skb);
1168 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */
1169 /* Flag byte to carry the start/end info */
1170 *dp++ = last << 7 | first << 6 | 1; /* EA */
1173 memcpy(dp, dlci->skb->data, len);
1174 skb_pull(dlci->skb, len);
1175 __gsm_data_queue(dlci, msg);
1177 dev_kfree_skb_any(dlci->skb);
1184 * gsm_dlci_modem_output - try and push modem status out of a DLCI
1186 * @dlci: the DLCI to pull modem status from
1187 * @brk: break signal
1189 * Push an empty frame in to the transmit queue to update the modem status
1190 * bits and to transmit an optional break.
1192 * Caller must hold the tx_lock of the mux.
1195 static int gsm_dlci_modem_output(struct gsm_mux *gsm, struct gsm_dlci *dlci,
1199 struct gsm_msg *msg;
1202 /* for modem bits without break data */
1203 switch (dlci->adaption) {
1204 case 1: /* Unstructured */
1206 case 2: /* Unstructured with modem bits. */
1212 pr_err("%s: unsupported adaption %d\n", __func__,
1217 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
1219 pr_err("%s: gsm_data_alloc error", __func__);
1223 switch (dlci->adaption) {
1224 case 1: /* Unstructured */
1226 case 2: /* Unstructured with modem bits. */
1228 *dp++ = (gsm_encode_modem(dlci) << 1) | EA;
1230 *dp++ = gsm_encode_modem(dlci) << 1;
1231 *dp++ = (brk << 4) | 2 | EA; /* Length, Break, EA */
1239 __gsm_data_queue(dlci, msg);
1244 * gsm_dlci_data_sweep - look for data to send
1247 * Sweep the GSM mux channels in priority order looking for ones with
1248 * data to send. We could do with optimising this scan a bit. We aim
1249 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit
1250 * TX_THRESH_LO we get called again
1252 * FIXME: We should round robin between groups and in theory you can
1253 * renegotiate DLCI priorities with optional stuff. Needs optimising.
1256 static int gsm_dlci_data_sweep(struct gsm_mux *gsm)
1258 /* Priority ordering: We should do priority with RR of the groups */
1259 int i, len, ret = 0;
1261 struct gsm_dlci *dlci;
1263 while (gsm->tx_bytes < TX_THRESH_HI) {
1264 for (sent = false, i = 1; i < NUM_DLCI; i++) {
1265 dlci = gsm->dlci[i];
1266 /* skip unused or blocked channel */
1267 if (!dlci || dlci->constipated)
1269 /* skip channels with invalid state */
1270 if (dlci->state != DLCI_OPEN)
1272 /* count the sent data per adaption */
1273 if (dlci->adaption < 3 && !dlci->net)
1274 len = gsm_dlci_data_output(gsm, dlci);
1276 len = gsm_dlci_data_output_framed(gsm, dlci);
1283 /* The lower DLCs can starve the higher DLCs! */
1296 * gsm_dlci_data_kick - transmit if possible
1297 * @dlci: DLCI to kick
1299 * Transmit data from this DLCI if the queue is empty. We can't rely on
1300 * a tty wakeup except when we filled the pipe so we need to fire off
1301 * new data ourselves in other cases.
1304 static void gsm_dlci_data_kick(struct gsm_dlci *dlci)
1306 unsigned long flags;
1309 if (dlci->constipated)
1312 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
1313 /* If we have nothing running then we need to fire up */
1314 sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO);
1315 if (dlci->gsm->tx_bytes == 0) {
1317 gsm_dlci_data_output_framed(dlci->gsm, dlci);
1319 gsm_dlci_data_output(dlci->gsm, dlci);
1322 gsm_dlci_data_sweep(dlci->gsm);
1323 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
1327 * Control message processing
1332 * gsm_control_command - send a command frame to a control
1334 * @cmd: the command to use
1335 * @data: data to follow encoded info
1336 * @dlen: length of data
1338 * Encode up and queue a UI/UIH frame containing our command.
1340 static int gsm_control_command(struct gsm_mux *gsm, int cmd, const u8 *data,
1343 struct gsm_msg *msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype);
1348 msg->data[0] = (cmd << 1) | CR | EA; /* Set C/R */
1349 msg->data[1] = (dlen << 1) | EA;
1350 memcpy(msg->data + 2, data, dlen);
1351 gsm_data_queue(gsm->dlci[0], msg);
1357 * gsm_control_reply - send a response frame to a control
1359 * @cmd: the command to use
1360 * @data: data to follow encoded info
1361 * @dlen: length of data
1363 * Encode up and queue a UI/UIH frame containing our response.
1366 static void gsm_control_reply(struct gsm_mux *gsm, int cmd, const u8 *data,
1369 struct gsm_msg *msg;
1370 msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype);
1373 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */
1374 msg->data[1] = (dlen << 1) | EA;
1375 memcpy(msg->data + 2, data, dlen);
1376 gsm_data_queue(gsm->dlci[0], msg);
1380 * gsm_process_modem - process received modem status
1381 * @tty: virtual tty bound to the DLCI
1382 * @dlci: DLCI to affect
1383 * @modem: modem bits (full EA)
1384 * @slen: number of signal octets
1386 * Used when a modem control message or line state inline in adaption
1387 * layer 2 is processed. Sort out the local modem state and throttles
1390 static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
1391 u32 modem, int slen)
1397 /* The modem status command can either contain one octet (V.24 signals)
1398 * or two octets (V.24 signals + break signals). This is specified in
1399 * section 5.4.6.3.7 of the 07.10 mux spec.
1403 modem = modem & 0x7f;
1406 modem = (modem >> 7) & 0x7f;
1409 /* Flow control/ready to communicate */
1410 fc = (modem & MDM_FC) || !(modem & MDM_RTR);
1411 if (fc && !dlci->constipated) {
1412 /* Need to throttle our output on this device */
1413 dlci->constipated = true;
1414 } else if (!fc && dlci->constipated) {
1415 dlci->constipated = false;
1416 gsm_dlci_data_kick(dlci);
1419 /* Map modem bits */
1420 if (modem & MDM_RTC)
1421 mlines |= TIOCM_DSR | TIOCM_DTR;
1422 if (modem & MDM_RTR)
1423 mlines |= TIOCM_RTS | TIOCM_CTS;
1429 /* Carrier drop -> hangup */
1431 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD))
1436 tty_insert_flip_char(&dlci->port, 0, TTY_BREAK);
1437 dlci->modem_rx = mlines;
1441 * gsm_control_modem - modem status received
1443 * @data: data following command
1444 * @clen: command length
1446 * We have received a modem status control message. This is used by
1447 * the GSM mux protocol to pass virtual modem line status and optionally
1448 * to indicate break signals. Unpack it, convert to Linux representation
1449 * and if need be stuff a break message down the tty.
1452 static void gsm_control_modem(struct gsm_mux *gsm, const u8 *data, int clen)
1454 unsigned int addr = 0;
1455 unsigned int modem = 0;
1456 struct gsm_dlci *dlci;
1459 const u8 *dp = data;
1460 struct tty_struct *tty;
1462 len = gsm_read_ea_val(&addr, data, cl);
1467 /* Closed port, or invalid ? */
1468 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1470 dlci = gsm->dlci[addr];
1472 /* Must be at least one byte following the EA */
1479 /* get the modem status */
1480 len = gsm_read_ea_val(&modem, dp, cl);
1484 tty = tty_port_tty_get(&dlci->port);
1485 gsm_process_modem(tty, dlci, modem, cl);
1490 gsm_control_reply(gsm, CMD_MSC, data, clen);
1494 * gsm_control_rls - remote line status
1497 * @clen: data length
1499 * The modem sends us a two byte message on the control channel whenever
1500 * it wishes to send us an error state from the virtual link. Stuff
1501 * this into the uplink tty if present
1504 static void gsm_control_rls(struct gsm_mux *gsm, const u8 *data, int clen)
1506 struct tty_port *port;
1507 unsigned int addr = 0;
1510 const u8 *dp = data;
1512 while (gsm_read_ea(&addr, *dp++) == 0) {
1517 /* Must be at least one byte following ea */
1522 /* Closed port, or invalid ? */
1523 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1527 if ((bits & 1) == 0)
1530 port = &gsm->dlci[addr]->port;
1533 tty_insert_flip_char(port, 0, TTY_OVERRUN);
1535 tty_insert_flip_char(port, 0, TTY_PARITY);
1537 tty_insert_flip_char(port, 0, TTY_FRAME);
1539 tty_flip_buffer_push(port);
1541 gsm_control_reply(gsm, CMD_RLS, data, clen);
1544 static void gsm_dlci_begin_close(struct gsm_dlci *dlci);
1547 * gsm_control_message - DLCI 0 control processing
1549 * @command: the command EA
1550 * @data: data beyond the command/length EAs
1553 * Input processor for control messages from the other end of the link.
1554 * Processes the incoming request and queues a response frame or an
1555 * NSC response if not supported
1558 static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
1559 const u8 *data, int clen)
1565 struct gsm_dlci *dlci = gsm->dlci[0];
1566 /* Modem wishes to close down */
1570 gsm_dlci_begin_close(dlci);
1575 /* Modem wishes to test, reply with the data */
1576 gsm_control_reply(gsm, CMD_TEST, data, clen);
1579 /* Modem can accept data again */
1580 gsm->constipated = false;
1581 gsm_control_reply(gsm, CMD_FCON, NULL, 0);
1582 /* Kick the link in case it is idling */
1583 gsmld_write_trigger(gsm);
1586 /* Modem wants us to STFU */
1587 gsm->constipated = true;
1588 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0);
1591 /* Out of band modem line change indicator for a DLCI */
1592 gsm_control_modem(gsm, data, clen);
1595 /* Out of band error reception for a DLCI */
1596 gsm_control_rls(gsm, data, clen);
1599 /* Modem wishes to enter power saving state */
1600 gsm_control_reply(gsm, CMD_PSC, NULL, 0);
1602 /* Optional unsupported commands */
1603 case CMD_PN: /* Parameter negotiation */
1604 case CMD_RPN: /* Remote port negotiation */
1605 case CMD_SNC: /* Service negotiation command */
1607 /* Reply to bad commands with an NSC */
1609 gsm_control_reply(gsm, CMD_NSC, buf, 1);
1615 * gsm_control_response - process a response to our control
1617 * @command: the command (response) EA
1618 * @data: data beyond the command/length EA
1621 * Process a response to an outstanding command. We only allow a single
1622 * control message in flight so this is fairly easy. All the clean up
1623 * is done by the caller, we just update the fields, flag it as done
1627 static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
1628 const u8 *data, int clen)
1630 struct gsm_control *ctrl;
1631 unsigned long flags;
1633 spin_lock_irqsave(&gsm->control_lock, flags);
1635 ctrl = gsm->pending_cmd;
1636 /* Does the reply match our command */
1638 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) {
1639 /* Our command was replied to, kill the retry timer */
1640 del_timer(&gsm->t2_timer);
1641 gsm->pending_cmd = NULL;
1642 /* Rejected by the other end */
1643 if (command == CMD_NSC)
1644 ctrl->error = -EOPNOTSUPP;
1646 wake_up(&gsm->event);
1648 spin_unlock_irqrestore(&gsm->control_lock, flags);
1652 * gsm_control_transmit - send control packet
1654 * @ctrl: frame to send
1656 * Send out a pending control command (called under control lock)
1659 static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl)
1661 gsm_control_command(gsm, ctrl->cmd, ctrl->data, ctrl->len);
1665 * gsm_control_retransmit - retransmit a control frame
1666 * @t: timer contained in our gsm object
1668 * Called off the T2 timer expiry in order to retransmit control frames
1669 * that have been lost in the system somewhere. The control_lock protects
1670 * us from colliding with another sender or a receive completion event.
1671 * In that situation the timer may still occur in a small window but
1672 * gsm->pending_cmd will be NULL and we just let the timer expire.
1675 static void gsm_control_retransmit(struct timer_list *t)
1677 struct gsm_mux *gsm = from_timer(gsm, t, t2_timer);
1678 struct gsm_control *ctrl;
1679 unsigned long flags;
1680 spin_lock_irqsave(&gsm->control_lock, flags);
1681 ctrl = gsm->pending_cmd;
1683 if (gsm->cretries == 0 || !gsm->dlci[0] || gsm->dlci[0]->dead) {
1684 gsm->pending_cmd = NULL;
1685 ctrl->error = -ETIMEDOUT;
1687 spin_unlock_irqrestore(&gsm->control_lock, flags);
1688 wake_up(&gsm->event);
1692 gsm_control_transmit(gsm, ctrl);
1693 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1695 spin_unlock_irqrestore(&gsm->control_lock, flags);
1699 * gsm_control_send - send a control frame on DLCI 0
1700 * @gsm: the GSM channel
1701 * @command: command to send including CR bit
1702 * @data: bytes of data (must be kmalloced)
1703 * @clen: length of the block to send
1705 * Queue and dispatch a control command. Only one command can be
1706 * active at a time. In theory more can be outstanding but the matching
1707 * gets really complicated so for now stick to one outstanding.
1710 static struct gsm_control *gsm_control_send(struct gsm_mux *gsm,
1711 unsigned int command, u8 *data, int clen)
1713 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control),
1715 unsigned long flags;
1719 wait_event(gsm->event, gsm->pending_cmd == NULL);
1720 spin_lock_irqsave(&gsm->control_lock, flags);
1721 if (gsm->pending_cmd != NULL) {
1722 spin_unlock_irqrestore(&gsm->control_lock, flags);
1725 ctrl->cmd = command;
1728 gsm->pending_cmd = ctrl;
1730 /* If DLCI0 is in ADM mode skip retries, it won't respond */
1731 if (gsm->dlci[0]->mode == DLCI_MODE_ADM)
1734 gsm->cretries = gsm->n2;
1736 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1737 gsm_control_transmit(gsm, ctrl);
1738 spin_unlock_irqrestore(&gsm->control_lock, flags);
1743 * gsm_control_wait - wait for a control to finish
1745 * @control: control we are waiting on
1747 * Waits for the control to complete or time out. Frees any used
1748 * resources and returns 0 for success, or an error if the remote
1749 * rejected or ignored the request.
1752 static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
1755 wait_event(gsm->event, control->done == 1);
1756 err = control->error;
1763 * DLCI level handling: Needs krefs
1767 * State transitions and timers
1771 * gsm_dlci_close - a DLCI has closed
1772 * @dlci: DLCI that closed
1774 * Perform processing when moving a DLCI into closed state. If there
1775 * is an attached tty this is hung up
1778 static void gsm_dlci_close(struct gsm_dlci *dlci)
1780 del_timer(&dlci->t1);
1781 if (debug & DBG_ERRORS)
1782 pr_debug("DLCI %d goes closed.\n", dlci->addr);
1783 dlci->state = DLCI_CLOSED;
1784 /* Prevent us from sending data before the link is up again */
1785 dlci->constipated = true;
1786 if (dlci->addr != 0) {
1787 tty_port_tty_hangup(&dlci->port, false);
1788 gsm_dlci_clear_queues(dlci->gsm, dlci);
1789 /* Ensure that gsmtty_open() can return. */
1790 tty_port_set_initialized(&dlci->port, 0);
1791 wake_up_interruptible(&dlci->port.open_wait);
1793 dlci->gsm->dead = true;
1794 /* A DLCI 0 close is a MUX termination so we need to kick that
1795 back to userspace somehow */
1796 gsm_dlci_data_kick(dlci);
1797 wake_up(&dlci->gsm->event);
1801 * gsm_dlci_open - a DLCI has opened
1802 * @dlci: DLCI that opened
1804 * Perform processing when moving a DLCI into open state.
1807 static void gsm_dlci_open(struct gsm_dlci *dlci)
1809 /* Note that SABM UA .. SABM UA first UA lost can mean that we go
1811 del_timer(&dlci->t1);
1812 /* This will let a tty open continue */
1813 dlci->state = DLCI_OPEN;
1814 dlci->constipated = false;
1815 if (debug & DBG_ERRORS)
1816 pr_debug("DLCI %d goes open.\n", dlci->addr);
1817 /* Send current modem state */
1819 gsm_modem_update(dlci, 0);
1820 gsm_dlci_data_kick(dlci);
1821 wake_up(&dlci->gsm->event);
1825 * gsm_dlci_t1 - T1 timer expiry
1826 * @t: timer contained in the DLCI that opened
1828 * The T1 timer handles retransmits of control frames (essentially of
1829 * SABM and DISC). We resend the command until the retry count runs out
1830 * in which case an opening port goes back to closed and a closing port
1831 * is simply put into closed state (any further frames from the other
1832 * end will get a DM response)
1834 * Some control dlci can stay in ADM mode with other dlci working just
1835 * fine. In that case we can just keep the control dlci open after the
1836 * DLCI_OPENING retries time out.
1839 static void gsm_dlci_t1(struct timer_list *t)
1841 struct gsm_dlci *dlci = from_timer(dlci, t, t1);
1842 struct gsm_mux *gsm = dlci->gsm;
1844 switch (dlci->state) {
1846 if (dlci->retries) {
1848 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1849 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1850 } else if (!dlci->addr && gsm->control == (DM | PF)) {
1851 if (debug & DBG_ERRORS)
1852 pr_info("DLCI %d opening in ADM mode.\n",
1854 dlci->mode = DLCI_MODE_ADM;
1855 gsm_dlci_open(dlci);
1857 gsm_dlci_begin_close(dlci); /* prevent half open link */
1862 if (dlci->retries) {
1864 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1865 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1867 gsm_dlci_close(dlci);
1870 pr_debug("%s: unhandled state: %d\n", __func__, dlci->state);
1876 * gsm_dlci_begin_open - start channel open procedure
1877 * @dlci: DLCI to open
1879 * Commence opening a DLCI from the Linux side. We issue SABM messages
1880 * to the modem which should then reply with a UA or ADM, at which point
1881 * we will move into open state. Opening is done asynchronously with retry
1882 * running off timers and the responses.
1885 static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
1887 struct gsm_mux *gsm = dlci->gsm;
1888 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING)
1890 dlci->retries = gsm->n2;
1891 dlci->state = DLCI_OPENING;
1892 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1893 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1897 * gsm_dlci_set_opening - change state to opening
1898 * @dlci: DLCI to open
1900 * Change internal state to wait for DLCI open from initiator side.
1901 * We set off timers and responses upon reception of an SABM.
1903 static void gsm_dlci_set_opening(struct gsm_dlci *dlci)
1905 switch (dlci->state) {
1908 dlci->state = DLCI_OPENING;
1916 * gsm_dlci_begin_close - start channel open procedure
1917 * @dlci: DLCI to open
1919 * Commence closing a DLCI from the Linux side. We issue DISC messages
1920 * to the modem which should then reply with a UA, at which point we
1921 * will move into closed state. Closing is done asynchronously with retry
1922 * off timers. We may also receive a DM reply from the other end which
1923 * indicates the channel was already closed.
1926 static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
1928 struct gsm_mux *gsm = dlci->gsm;
1929 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
1931 dlci->retries = gsm->n2;
1932 dlci->state = DLCI_CLOSING;
1933 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1934 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1938 * gsm_dlci_data - data arrived
1940 * @data: block of bytes received
1941 * @clen: length of received block
1943 * A UI or UIH frame has arrived which contains data for a channel
1944 * other than the control channel. If the relevant virtual tty is
1945 * open we shovel the bits down it, if not we drop them.
1948 static void gsm_dlci_data(struct gsm_dlci *dlci, const u8 *data, int clen)
1951 struct tty_port *port = &dlci->port;
1952 struct tty_struct *tty;
1953 unsigned int modem = 0;
1956 if (debug & DBG_TTY)
1957 pr_debug("%d bytes for tty\n", clen);
1958 switch (dlci->adaption) {
1959 /* Unsupported types */
1960 case 4: /* Packetised interruptible data */
1962 case 3: /* Packetised uininterruptible voice/data */
1964 case 2: /* Asynchronous serial with line state in each frame */
1965 len = gsm_read_ea_val(&modem, data, clen);
1968 tty = tty_port_tty_get(port);
1970 gsm_process_modem(tty, dlci, modem, len);
1974 /* Skip processed modem data */
1978 case 1: /* Line state will go via DLCI 0 controls only */
1980 tty_insert_flip_string(port, data, clen);
1981 tty_flip_buffer_push(port);
1986 * gsm_dlci_command - data arrived on control channel
1988 * @data: block of bytes received
1989 * @len: length of received block
1991 * A UI or UIH frame has arrived which contains data for DLCI 0 the
1992 * control channel. This should contain a command EA followed by
1993 * control data bytes. The command EA contains a command/response bit
1994 * and we divide up the work accordingly.
1997 static void gsm_dlci_command(struct gsm_dlci *dlci, const u8 *data, int len)
1999 /* See what command is involved */
2000 unsigned int command = 0;
2001 unsigned int clen = 0;
2004 /* read the command */
2005 dlen = gsm_read_ea_val(&command, data, len);
2009 /* read any control data */
2010 dlen = gsm_read_ea_val(&clen, data, len);
2014 /* Malformed command? */
2019 gsm_control_message(dlci->gsm, command, data, clen);
2021 gsm_control_response(dlci->gsm, command, data, clen);
2025 * gsm_kick_timer - transmit if possible
2026 * @t: timer contained in our gsm object
2028 * Transmit data from DLCIs if the queue is empty. We can't rely on
2029 * a tty wakeup except when we filled the pipe so we need to fire off
2030 * new data ourselves in other cases.
2032 static void gsm_kick_timer(struct timer_list *t)
2034 struct gsm_mux *gsm = from_timer(gsm, t, kick_timer);
2035 unsigned long flags;
2038 spin_lock_irqsave(&gsm->tx_lock, flags);
2039 /* If we have nothing running then we need to fire up */
2040 if (gsm->tx_bytes < TX_THRESH_LO)
2041 sent = gsm_dlci_data_sweep(gsm);
2042 spin_unlock_irqrestore(&gsm->tx_lock, flags);
2044 if (sent && debug & DBG_DATA)
2045 pr_info("%s TX queue stalled\n", __func__);
2049 * Allocate/Free DLCI channels
2053 * gsm_dlci_alloc - allocate a DLCI
2055 * @addr: address of the DLCI
2057 * Allocate and install a new DLCI object into the GSM mux.
2059 * FIXME: review locking races
2062 static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
2064 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC);
2067 spin_lock_init(&dlci->lock);
2068 mutex_init(&dlci->mutex);
2069 if (kfifo_alloc(&dlci->fifo, TX_SIZE, GFP_KERNEL) < 0) {
2074 skb_queue_head_init(&dlci->skb_list);
2075 timer_setup(&dlci->t1, gsm_dlci_t1, 0);
2076 tty_port_init(&dlci->port);
2077 dlci->port.ops = &gsm_port_ops;
2080 dlci->adaption = gsm->adaption;
2081 dlci->state = DLCI_CLOSED;
2083 dlci->data = gsm_dlci_data;
2084 /* Prevent us from sending data before the link is up */
2085 dlci->constipated = true;
2087 dlci->data = gsm_dlci_command;
2089 gsm->dlci[addr] = dlci;
2094 * gsm_dlci_free - free DLCI
2095 * @port: tty port for DLCI to free
2101 static void gsm_dlci_free(struct tty_port *port)
2103 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2105 del_timer_sync(&dlci->t1);
2106 dlci->gsm->dlci[dlci->addr] = NULL;
2107 kfifo_free(&dlci->fifo);
2108 while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
2109 dev_kfree_skb(dlci->skb);
2113 static inline void dlci_get(struct gsm_dlci *dlci)
2115 tty_port_get(&dlci->port);
2118 static inline void dlci_put(struct gsm_dlci *dlci)
2120 tty_port_put(&dlci->port);
2123 static void gsm_destroy_network(struct gsm_dlci *dlci);
2126 * gsm_dlci_release - release DLCI
2127 * @dlci: DLCI to destroy
2129 * Release a DLCI. Actual free is deferred until either
2130 * mux is closed or tty is closed - whichever is last.
2134 static void gsm_dlci_release(struct gsm_dlci *dlci)
2136 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
2138 mutex_lock(&dlci->mutex);
2139 gsm_destroy_network(dlci);
2140 mutex_unlock(&dlci->mutex);
2142 /* We cannot use tty_hangup() because in tty_kref_put() the tty
2143 * driver assumes that the hangup queue is free and reuses it to
2144 * queue release_one_tty() -> NULL pointer panic in
2145 * process_one_work().
2149 tty_port_tty_set(&dlci->port, NULL);
2152 dlci->state = DLCI_CLOSED;
2157 * LAPBish link layer logic
2161 * gsm_queue - a GSM frame is ready to process
2162 * @gsm: pointer to our gsm mux
2164 * At this point in time a frame has arrived and been demangled from
2165 * the line encoding. All the differences between the encodings have
2166 * been handled below us and the frame is unpacked into the structures.
2167 * The fcs holds the header FCS but any data FCS must be added here.
2170 static void gsm_queue(struct gsm_mux *gsm)
2172 struct gsm_dlci *dlci;
2176 if (gsm->fcs != GOOD_FCS) {
2178 if (debug & DBG_DATA)
2179 pr_debug("BAD FCS %02x\n", gsm->fcs);
2182 address = gsm->address >> 1;
2183 if (address >= NUM_DLCI)
2186 cr = gsm->address & 1; /* C/R bit */
2187 cr ^= gsm->initiator ? 0 : 1; /* Flip so 1 always means command */
2189 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
2191 dlci = gsm->dlci[address];
2193 switch (gsm->control) {
2198 dlci = gsm_dlci_alloc(gsm, address);
2202 gsm_response(gsm, address, DM|PF);
2204 gsm_response(gsm, address, UA|PF);
2205 gsm_dlci_open(dlci);
2211 if (dlci == NULL || dlci->state == DLCI_CLOSED) {
2212 gsm_response(gsm, address, DM|PF);
2215 /* Real close complete */
2216 gsm_response(gsm, address, UA|PF);
2217 gsm_dlci_close(dlci);
2220 if (cr == 0 || dlci == NULL)
2222 switch (dlci->state) {
2224 gsm_dlci_close(dlci);
2227 gsm_dlci_open(dlci);
2230 pr_debug("%s: unhandled state: %d\n", __func__,
2235 case DM: /* DM can be valid unsolicited */
2241 gsm_dlci_close(dlci);
2247 if (dlci == NULL || dlci->state != DLCI_OPEN) {
2248 gsm_response(gsm, address, DM|PF);
2251 dlci->data(dlci, gsm->buf, gsm->len);
2264 * gsm0_receive - perform processing for non-transparency
2265 * @gsm: gsm data for this ldisc instance
2268 * Receive bytes in gsm mode 0
2271 static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
2275 switch (gsm->state) {
2276 case GSM_SEARCH: /* SOF marker */
2277 if (c == GSM0_SOF) {
2278 gsm->state = GSM_ADDRESS;
2281 gsm->fcs = INIT_FCS;
2284 case GSM_ADDRESS: /* Address EA */
2285 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2286 if (gsm_read_ea(&gsm->address, c))
2287 gsm->state = GSM_CONTROL;
2289 case GSM_CONTROL: /* Control Byte */
2290 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2292 gsm->state = GSM_LEN0;
2294 case GSM_LEN0: /* Length EA */
2295 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2296 if (gsm_read_ea(&gsm->len, c)) {
2297 if (gsm->len > gsm->mru) {
2299 gsm->state = GSM_SEARCH;
2304 gsm->state = GSM_FCS;
2306 gsm->state = GSM_DATA;
2309 gsm->state = GSM_LEN1;
2312 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2314 gsm->len |= len << 7;
2315 if (gsm->len > gsm->mru) {
2317 gsm->state = GSM_SEARCH;
2322 gsm->state = GSM_FCS;
2324 gsm->state = GSM_DATA;
2326 case GSM_DATA: /* Data */
2327 gsm->buf[gsm->count++] = c;
2328 if (gsm->count == gsm->len) {
2329 /* Calculate final FCS for UI frames over all data */
2330 if ((gsm->control & ~PF) != UIH) {
2331 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf,
2334 gsm->state = GSM_FCS;
2337 case GSM_FCS: /* FCS follows the packet */
2338 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2339 gsm->state = GSM_SSOF;
2342 gsm->state = GSM_SEARCH;
2349 pr_debug("%s: unhandled state: %d\n", __func__, gsm->state);
2355 * gsm1_receive - perform processing for non-transparency
2356 * @gsm: gsm data for this ldisc instance
2359 * Receive bytes in mode 1 (Advanced option)
2362 static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
2364 /* handle XON/XOFF */
2365 if ((c & ISO_IEC_646_MASK) == XON) {
2366 gsm->constipated = true;
2368 } else if ((c & ISO_IEC_646_MASK) == XOFF) {
2369 gsm->constipated = false;
2370 /* Kick the link in case it is idling */
2371 gsmld_write_trigger(gsm);
2374 if (c == GSM1_SOF) {
2375 /* EOF is only valid in frame if we have got to the data state */
2376 if (gsm->state == GSM_DATA) {
2377 if (gsm->count < 1) {
2380 gsm->state = GSM_START;
2383 /* Remove the FCS from data */
2385 if ((gsm->control & ~PF) != UIH) {
2386 /* Calculate final FCS for UI frames over all
2389 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf,
2392 /* Add the FCS itself to test against GOOD_FCS */
2393 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
2394 gsm->len = gsm->count;
2396 gsm->state = GSM_START;
2399 /* Any partial frame was a runt so go back to start */
2400 if (gsm->state != GSM_START) {
2401 if (gsm->state != GSM_SEARCH)
2403 gsm->state = GSM_START;
2405 /* A SOF in GSM_START means we are still reading idling or
2410 if (c == GSM1_ESCAPE) {
2415 /* Only an unescaped SOF gets us out of GSM search */
2416 if (gsm->state == GSM_SEARCH)
2420 c ^= GSM1_ESCAPE_BITS;
2421 gsm->escape = false;
2423 switch (gsm->state) {
2424 case GSM_START: /* First byte after SOF */
2426 gsm->state = GSM_ADDRESS;
2427 gsm->fcs = INIT_FCS;
2429 case GSM_ADDRESS: /* Address continuation */
2430 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2431 if (gsm_read_ea(&gsm->address, c))
2432 gsm->state = GSM_CONTROL;
2434 case GSM_CONTROL: /* Control Byte */
2435 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2438 gsm->state = GSM_DATA;
2440 case GSM_DATA: /* Data */
2441 if (gsm->count > gsm->mru) { /* Allow one for the FCS */
2442 gsm->state = GSM_OVERRUN;
2445 gsm->buf[gsm->count++] = c;
2447 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */
2450 pr_debug("%s: unhandled state: %d\n", __func__, gsm->state);
2456 * gsm_error - handle tty error
2459 * Handle an error in the receipt of data for a frame. Currently we just
2460 * go back to hunting for a SOF.
2462 * FIXME: better diagnostics ?
2465 static void gsm_error(struct gsm_mux *gsm)
2467 gsm->state = GSM_SEARCH;
2472 * gsm_cleanup_mux - generic GSM protocol cleanup
2474 * @disc: disconnect link?
2476 * Clean up the bits of the mux which are the same for all framing
2477 * protocols. Remove the mux from the mux table, stop all the timers
2478 * and then shut down each device hanging up the channels as we go.
2481 static void gsm_cleanup_mux(struct gsm_mux *gsm, bool disc)
2484 struct gsm_dlci *dlci;
2485 struct gsm_msg *txq, *ntxq;
2488 mutex_lock(&gsm->mutex);
2490 dlci = gsm->dlci[0];
2492 if (disc && dlci->state != DLCI_CLOSED) {
2493 gsm_dlci_begin_close(dlci);
2494 wait_event(gsm->event, dlci->state == DLCI_CLOSED);
2499 /* Finish outstanding timers, making sure they are done */
2500 del_timer_sync(&gsm->kick_timer);
2501 del_timer_sync(&gsm->t2_timer);
2503 /* Finish writing to ldisc */
2504 flush_work(&gsm->tx_work);
2506 /* Free up any link layer users and finally the control channel */
2507 if (gsm->has_devices) {
2508 gsm_unregister_devices(gsm_tty_driver, gsm->num);
2509 gsm->has_devices = false;
2511 for (i = NUM_DLCI - 1; i >= 0; i--)
2513 gsm_dlci_release(gsm->dlci[i]);
2514 mutex_unlock(&gsm->mutex);
2515 /* Now wipe the queues */
2516 tty_ldisc_flush(gsm->tty);
2517 list_for_each_entry_safe(txq, ntxq, &gsm->tx_ctrl_list, list)
2519 INIT_LIST_HEAD(&gsm->tx_ctrl_list);
2520 list_for_each_entry_safe(txq, ntxq, &gsm->tx_data_list, list)
2522 INIT_LIST_HEAD(&gsm->tx_data_list);
2526 * gsm_activate_mux - generic GSM setup
2529 * Set up the bits of the mux which are the same for all framing
2530 * protocols. Add the mux to the mux table so it can be opened and
2531 * finally kick off connecting to DLCI 0 on the modem.
2534 static int gsm_activate_mux(struct gsm_mux *gsm)
2536 struct gsm_dlci *dlci;
2539 dlci = gsm_dlci_alloc(gsm, 0);
2543 if (gsm->encoding == GSM_BASIC_OPT)
2544 gsm->receive = gsm0_receive;
2546 gsm->receive = gsm1_receive;
2548 ret = gsm_register_devices(gsm_tty_driver, gsm->num);
2552 gsm->has_devices = true;
2553 gsm->dead = false; /* Tty opens are now permissible */
2558 * gsm_free_mux - free up a mux
2561 * Dispose of allocated resources for a dead mux
2563 static void gsm_free_mux(struct gsm_mux *gsm)
2567 for (i = 0; i < MAX_MUX; i++) {
2568 if (gsm == gsm_mux[i]) {
2573 mutex_destroy(&gsm->mutex);
2574 kfree(gsm->txframe);
2580 * gsm_free_muxr - free up a mux
2581 * @ref: kreference to the mux to free
2583 * Dispose of allocated resources for a dead mux
2585 static void gsm_free_muxr(struct kref *ref)
2587 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref);
2591 static inline void mux_get(struct gsm_mux *gsm)
2593 unsigned long flags;
2595 spin_lock_irqsave(&gsm_mux_lock, flags);
2596 kref_get(&gsm->ref);
2597 spin_unlock_irqrestore(&gsm_mux_lock, flags);
2600 static inline void mux_put(struct gsm_mux *gsm)
2602 unsigned long flags;
2604 spin_lock_irqsave(&gsm_mux_lock, flags);
2605 kref_put(&gsm->ref, gsm_free_muxr);
2606 spin_unlock_irqrestore(&gsm_mux_lock, flags);
2609 static inline unsigned int mux_num_to_base(struct gsm_mux *gsm)
2611 return gsm->num * NUM_DLCI;
2614 static inline unsigned int mux_line_to_num(unsigned int line)
2616 return line / NUM_DLCI;
2620 * gsm_alloc_mux - allocate a mux
2622 * Creates a new mux ready for activation.
2625 static struct gsm_mux *gsm_alloc_mux(void)
2628 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
2631 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL);
2632 if (gsm->buf == NULL) {
2636 gsm->txframe = kmalloc(2 * (MAX_MTU + PROT_OVERHEAD - 1), GFP_KERNEL);
2637 if (gsm->txframe == NULL) {
2642 spin_lock_init(&gsm->lock);
2643 mutex_init(&gsm->mutex);
2644 kref_init(&gsm->ref);
2645 INIT_LIST_HEAD(&gsm->tx_ctrl_list);
2646 INIT_LIST_HEAD(&gsm->tx_data_list);
2647 timer_setup(&gsm->kick_timer, gsm_kick_timer, 0);
2648 timer_setup(&gsm->t2_timer, gsm_control_retransmit, 0);
2649 INIT_WORK(&gsm->tx_work, gsmld_write_task);
2650 init_waitqueue_head(&gsm->event);
2651 spin_lock_init(&gsm->control_lock);
2652 spin_lock_init(&gsm->tx_lock);
2659 gsm->encoding = GSM_ADV_OPT;
2660 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
2662 gsm->dead = true; /* Avoid early tty opens */
2664 /* Store the instance to the mux array or abort if no space is
2667 spin_lock(&gsm_mux_lock);
2668 for (i = 0; i < MAX_MUX; i++) {
2675 spin_unlock(&gsm_mux_lock);
2677 mutex_destroy(&gsm->mutex);
2678 kfree(gsm->txframe);
2687 static void gsm_copy_config_values(struct gsm_mux *gsm,
2688 struct gsm_config *c)
2690 memset(c, 0, sizeof(*c));
2691 c->adaption = gsm->adaption;
2692 c->encapsulation = gsm->encoding;
2693 c->initiator = gsm->initiator;
2696 c->t3 = 0; /* Not supported */
2698 if (gsm->ftype == UIH)
2702 pr_debug("Ftype %d i %d\n", gsm->ftype, c->i);
2708 static int gsm_config(struct gsm_mux *gsm, struct gsm_config *c)
2712 int need_restart = 0;
2714 /* Stuff we don't support yet - UI or I frame transport, windowing */
2715 if ((c->adaption != 1 && c->adaption != 2) || c->k)
2717 /* Check the MRU/MTU range looks sane */
2718 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8)
2722 if (c->encapsulation > 1) /* Basic, advanced, no I */
2724 if (c->initiator > 1)
2726 if (c->i == 0 || c->i > 2) /* UIH and UI only */
2729 * See what is needed for reconfiguration
2733 if (c->t1 != 0 && c->t1 != gsm->t1)
2735 if (c->t2 != 0 && c->t2 != gsm->t2)
2737 if (c->encapsulation != gsm->encoding)
2739 if (c->adaption != gsm->adaption)
2742 if (c->initiator != gsm->initiator)
2744 if (c->mru != gsm->mru)
2746 if (c->mtu != gsm->mtu)
2750 * Close down what is needed, restart and initiate the new
2751 * configuration. On the first time there is no DLCI[0]
2752 * and closing or cleaning up is not necessary.
2754 if (need_close || need_restart)
2755 gsm_cleanup_mux(gsm, true);
2757 gsm->initiator = c->initiator;
2760 gsm->encoding = c->encapsulation ? GSM_ADV_OPT : GSM_BASIC_OPT;
2761 gsm->adaption = c->adaption;
2775 * FIXME: We need to separate activation/deactivation from adding
2776 * and removing from the mux array
2779 ret = gsm_activate_mux(gsm);
2783 gsm_dlci_begin_open(gsm->dlci[0]);
2789 * gsmld_output - write to link
2791 * @data: bytes to output
2794 * Write a block of data from the GSM mux to the data channel. This
2795 * will eventually be serialized from above but at the moment isn't.
2798 static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
2800 if (tty_write_room(gsm->tty) < len) {
2801 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
2804 if (debug & DBG_DATA)
2805 gsm_hex_dump_bytes(__func__, data, len);
2806 return gsm->tty->ops->write(gsm->tty, data, len);
2811 * gsmld_write_trigger - schedule ldisc write task
2814 static void gsmld_write_trigger(struct gsm_mux *gsm)
2816 if (!gsm || !gsm->dlci[0] || gsm->dlci[0]->dead)
2818 schedule_work(&gsm->tx_work);
2823 * gsmld_write_task - ldisc write task
2824 * @work: our tx write work
2826 * Writes out data to the ldisc if possible. We are doing this here to
2827 * avoid dead-locking. This returns if no space or data is left for output.
2829 static void gsmld_write_task(struct work_struct *work)
2831 struct gsm_mux *gsm = container_of(work, struct gsm_mux, tx_work);
2832 unsigned long flags;
2835 /* All outstanding control channel and control messages and one data
2839 spin_lock_irqsave(&gsm->tx_lock, flags);
2841 ret = gsm_data_kick(gsm);
2842 spin_unlock_irqrestore(&gsm->tx_lock, flags);
2845 for (i = 0; i < NUM_DLCI; i++)
2847 tty_port_tty_wakeup(&gsm->dlci[i]->port);
2851 * gsmld_attach_gsm - mode set up
2852 * @tty: our tty structure
2855 * Set up the MUX for basic mode and commence connecting to the
2856 * modem. Currently called from the line discipline set up but
2857 * will need moving to an ioctl path.
2860 static void gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2862 gsm->tty = tty_kref_get(tty);
2863 /* Turn off tty XON/XOFF handling to handle it explicitly. */
2864 gsm->old_c_iflag = tty->termios.c_iflag;
2865 tty->termios.c_iflag &= (IXON | IXOFF);
2869 * gsmld_detach_gsm - stop doing 0710 mux
2870 * @tty: tty attached to the mux
2873 * Shutdown and then clean up the resources used by the line discipline
2876 static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2878 WARN_ON(tty != gsm->tty);
2879 /* Restore tty XON/XOFF handling. */
2880 gsm->tty->termios.c_iflag = gsm->old_c_iflag;
2881 tty_kref_put(gsm->tty);
2885 static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
2886 const char *fp, int count)
2888 struct gsm_mux *gsm = tty->disc_data;
2889 char flags = TTY_NORMAL;
2891 if (debug & DBG_DATA)
2892 gsm_hex_dump_bytes(__func__, cp, count);
2894 for (; count; count--, cp++) {
2900 gsm->receive(gsm, *cp);
2909 WARN_ONCE(1, "%s: unknown flag %d\n",
2910 tty_name(tty), flags);
2914 /* FASYNC if needed ? */
2915 /* If clogged call tty_throttle(tty); */
2919 * gsmld_flush_buffer - clean input queue
2920 * @tty: terminal device
2922 * Flush the input buffer. Called when the line discipline is
2923 * being closed, when the tty layer wants the buffer flushed (eg
2927 static void gsmld_flush_buffer(struct tty_struct *tty)
2932 * gsmld_close - close the ldisc for this tty
2935 * Called from the terminal layer when this line discipline is
2936 * being shut down, either because of a close or becsuse of a
2937 * discipline change. The function will not be called while other
2938 * ldisc methods are in progress.
2941 static void gsmld_close(struct tty_struct *tty)
2943 struct gsm_mux *gsm = tty->disc_data;
2945 /* The ldisc locks and closes the port before calling our close. This
2946 * means we have no way to do a proper disconnect. We will not bother
2949 gsm_cleanup_mux(gsm, false);
2951 gsmld_detach_gsm(tty, gsm);
2953 gsmld_flush_buffer(tty);
2954 /* Do other clean up here */
2959 * gsmld_open - open an ldisc
2960 * @tty: terminal to open
2962 * Called when this line discipline is being attached to the
2963 * terminal device. Can sleep. Called serialized so that no
2964 * other events will occur in parallel. No further open will occur
2968 static int gsmld_open(struct tty_struct *tty)
2970 struct gsm_mux *gsm;
2972 if (tty->ops->write == NULL)
2975 /* Attach our ldisc data */
2976 gsm = gsm_alloc_mux();
2980 tty->disc_data = gsm;
2981 tty->receive_room = 65536;
2983 /* Attach the initial passive connection */
2984 gsm->encoding = GSM_ADV_OPT;
2985 gsmld_attach_gsm(tty, gsm);
2991 * gsmld_write_wakeup - asynchronous I/O notifier
2994 * Required for the ptys, serial driver etc. since processes
2995 * that attach themselves to the master and rely on ASYNC
2996 * IO must be woken up
2999 static void gsmld_write_wakeup(struct tty_struct *tty)
3001 struct gsm_mux *gsm = tty->disc_data;
3004 gsmld_write_trigger(gsm);
3008 * gsmld_read - read function for tty
3010 * @file: file object
3011 * @buf: userspace buffer pointer
3016 * Perform reads for the line discipline. We are guaranteed that the
3017 * line discipline will not be closed under us but we may get multiple
3018 * parallel readers and must handle this ourselves. We may also get
3019 * a hangup. Always called in user context, may sleep.
3021 * This code must be sure never to sleep through a hangup.
3024 static ssize_t gsmld_read(struct tty_struct *tty, struct file *file,
3025 unsigned char *buf, size_t nr,
3026 void **cookie, unsigned long offset)
3032 * gsmld_write - write function for tty
3034 * @file: file object
3035 * @buf: userspace buffer pointer
3038 * Called when the owner of the device wants to send a frame
3039 * itself (or some other control data). The data is transferred
3040 * as-is and must be properly framed and checksummed as appropriate
3041 * by userspace. Frames are either sent whole or not at all as this
3042 * avoids pain user side.
3045 static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
3046 const unsigned char *buf, size_t nr)
3048 struct gsm_mux *gsm = tty->disc_data;
3049 unsigned long flags;
3057 spin_lock_irqsave(&gsm->tx_lock, flags);
3058 space = tty_write_room(tty);
3060 ret = tty->ops->write(tty, buf, nr);
3062 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
3063 spin_unlock_irqrestore(&gsm->tx_lock, flags);
3069 * gsmld_poll - poll method for N_GSM0710
3070 * @tty: terminal device
3071 * @file: file accessing it
3074 * Called when the line discipline is asked to poll() for data or
3075 * for special events. This code is not serialized with respect to
3076 * other events save open/close.
3078 * This code must be sure never to sleep through a hangup.
3079 * Called without the kernel lock held - fine
3082 static __poll_t gsmld_poll(struct tty_struct *tty, struct file *file,
3086 struct gsm_mux *gsm = tty->disc_data;
3088 poll_wait(file, &tty->read_wait, wait);
3089 poll_wait(file, &tty->write_wait, wait);
3093 if (tty_hung_up_p(file))
3095 if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
3097 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
3098 mask |= EPOLLOUT | EPOLLWRNORM;
3102 static int gsmld_ioctl(struct tty_struct *tty, unsigned int cmd,
3105 struct gsm_config c;
3106 struct gsm_mux *gsm = tty->disc_data;
3110 case GSMIOC_GETCONF:
3111 gsm_copy_config_values(gsm, &c);
3112 if (copy_to_user((void __user *)arg, &c, sizeof(c)))
3115 case GSMIOC_SETCONF:
3116 if (copy_from_user(&c, (void __user *)arg, sizeof(c)))
3118 return gsm_config(gsm, &c);
3119 case GSMIOC_GETFIRST:
3120 base = mux_num_to_base(gsm);
3121 return put_user(base + 1, (__u32 __user *)arg);
3123 return n_tty_ioctl_helper(tty, cmd, arg);
3132 static int gsm_mux_net_open(struct net_device *net)
3134 pr_debug("%s called\n", __func__);
3135 netif_start_queue(net);
3139 static int gsm_mux_net_close(struct net_device *net)
3141 netif_stop_queue(net);
3145 static void dlci_net_free(struct gsm_dlci *dlci)
3151 dlci->adaption = dlci->prev_adaption;
3152 dlci->data = dlci->prev_data;
3153 free_netdev(dlci->net);
3156 static void net_free(struct kref *ref)
3158 struct gsm_mux_net *mux_net;
3159 struct gsm_dlci *dlci;
3161 mux_net = container_of(ref, struct gsm_mux_net, ref);
3162 dlci = mux_net->dlci;
3165 unregister_netdev(dlci->net);
3166 dlci_net_free(dlci);
3170 static inline void muxnet_get(struct gsm_mux_net *mux_net)
3172 kref_get(&mux_net->ref);
3175 static inline void muxnet_put(struct gsm_mux_net *mux_net)
3177 kref_put(&mux_net->ref, net_free);
3180 static netdev_tx_t gsm_mux_net_start_xmit(struct sk_buff *skb,
3181 struct net_device *net)
3183 struct gsm_mux_net *mux_net = netdev_priv(net);
3184 struct gsm_dlci *dlci = mux_net->dlci;
3185 muxnet_get(mux_net);
3187 skb_queue_head(&dlci->skb_list, skb);
3188 net->stats.tx_packets++;
3189 net->stats.tx_bytes += skb->len;
3190 gsm_dlci_data_kick(dlci);
3191 /* And tell the kernel when the last transmit started. */
3192 netif_trans_update(net);
3193 muxnet_put(mux_net);
3194 return NETDEV_TX_OK;
3197 /* called when a packet did not ack after watchdogtimeout */
3198 static void gsm_mux_net_tx_timeout(struct net_device *net, unsigned int txqueue)
3200 /* Tell syslog we are hosed. */
3201 dev_dbg(&net->dev, "Tx timed out.\n");
3203 /* Update statistics */
3204 net->stats.tx_errors++;
3207 static void gsm_mux_rx_netchar(struct gsm_dlci *dlci,
3208 const unsigned char *in_buf, int size)
3210 struct net_device *net = dlci->net;
3211 struct sk_buff *skb;
3212 struct gsm_mux_net *mux_net = netdev_priv(net);
3213 muxnet_get(mux_net);
3215 /* Allocate an sk_buff */
3216 skb = dev_alloc_skb(size + NET_IP_ALIGN);
3218 /* We got no receive buffer. */
3219 net->stats.rx_dropped++;
3220 muxnet_put(mux_net);
3223 skb_reserve(skb, NET_IP_ALIGN);
3224 skb_put_data(skb, in_buf, size);
3227 skb->protocol = htons(ETH_P_IP);
3229 /* Ship it off to the kernel */
3232 /* update out statistics */
3233 net->stats.rx_packets++;
3234 net->stats.rx_bytes += size;
3235 muxnet_put(mux_net);
3239 static void gsm_mux_net_init(struct net_device *net)
3241 static const struct net_device_ops gsm_netdev_ops = {
3242 .ndo_open = gsm_mux_net_open,
3243 .ndo_stop = gsm_mux_net_close,
3244 .ndo_start_xmit = gsm_mux_net_start_xmit,
3245 .ndo_tx_timeout = gsm_mux_net_tx_timeout,
3248 net->netdev_ops = &gsm_netdev_ops;
3250 /* fill in the other fields */
3251 net->watchdog_timeo = GSM_NET_TX_TIMEOUT;
3252 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
3253 net->type = ARPHRD_NONE;
3254 net->tx_queue_len = 10;
3258 /* caller holds the dlci mutex */
3259 static void gsm_destroy_network(struct gsm_dlci *dlci)
3261 struct gsm_mux_net *mux_net;
3263 pr_debug("destroy network interface\n");
3266 mux_net = netdev_priv(dlci->net);
3267 muxnet_put(mux_net);
3271 /* caller holds the dlci mutex */
3272 static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
3276 struct net_device *net;
3277 struct gsm_mux_net *mux_net;
3279 if (!capable(CAP_NET_ADMIN))
3282 /* Already in a non tty mode */
3283 if (dlci->adaption > 2)
3286 if (nc->protocol != htons(ETH_P_IP))
3287 return -EPROTONOSUPPORT;
3289 if (nc->adaption != 3 && nc->adaption != 4)
3290 return -EPROTONOSUPPORT;
3292 pr_debug("create network interface\n");
3295 if (nc->if_name[0] != '\0')
3296 netname = nc->if_name;
3297 net = alloc_netdev(sizeof(struct gsm_mux_net), netname,
3298 NET_NAME_UNKNOWN, gsm_mux_net_init);
3300 pr_err("alloc_netdev failed\n");
3303 net->mtu = dlci->gsm->mtu;
3305 net->max_mtu = dlci->gsm->mtu;
3306 mux_net = netdev_priv(net);
3307 mux_net->dlci = dlci;
3308 kref_init(&mux_net->ref);
3309 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */
3311 /* reconfigure dlci for network */
3312 dlci->prev_adaption = dlci->adaption;
3313 dlci->prev_data = dlci->data;
3314 dlci->adaption = nc->adaption;
3315 dlci->data = gsm_mux_rx_netchar;
3318 pr_debug("register netdev\n");
3319 retval = register_netdev(net);
3321 pr_err("network register fail %d\n", retval);
3322 dlci_net_free(dlci);
3325 return net->ifindex; /* return network index */
3328 /* Line discipline for real tty */
3329 static struct tty_ldisc_ops tty_ldisc_packet = {
3330 .owner = THIS_MODULE,
3334 .close = gsmld_close,
3335 .flush_buffer = gsmld_flush_buffer,
3337 .write = gsmld_write,
3338 .ioctl = gsmld_ioctl,
3340 .receive_buf = gsmld_receive_buf,
3341 .write_wakeup = gsmld_write_wakeup
3349 * gsm_modem_upd_via_data - send modem bits via convergence layer
3351 * @brk: break signal
3353 * Send an empty frame to signal mobile state changes and to transmit the
3354 * break signal for adaption 2.
3357 static void gsm_modem_upd_via_data(struct gsm_dlci *dlci, u8 brk)
3359 struct gsm_mux *gsm = dlci->gsm;
3360 unsigned long flags;
3362 if (dlci->state != DLCI_OPEN || dlci->adaption != 2)
3365 spin_lock_irqsave(&gsm->tx_lock, flags);
3366 gsm_dlci_modem_output(gsm, dlci, brk);
3367 spin_unlock_irqrestore(&gsm->tx_lock, flags);
3371 * gsm_modem_upd_via_msc - send modem bits via control frame
3373 * @brk: break signal
3376 static int gsm_modem_upd_via_msc(struct gsm_dlci *dlci, u8 brk)
3379 struct gsm_control *ctrl;
3382 if (dlci->gsm->encoding != GSM_BASIC_OPT)
3385 modembits[0] = (dlci->addr << 2) | 2 | EA; /* DLCI, Valid, EA */
3387 modembits[1] = (gsm_encode_modem(dlci) << 1) | EA;
3389 modembits[1] = gsm_encode_modem(dlci) << 1;
3390 modembits[2] = (brk << 4) | 2 | EA; /* Length, Break, EA */
3393 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len);
3396 return gsm_control_wait(dlci->gsm, ctrl);
3400 * gsm_modem_update - send modem status line state
3402 * @brk: break signal
3405 static int gsm_modem_update(struct gsm_dlci *dlci, u8 brk)
3407 if (dlci->adaption == 2) {
3408 /* Send convergence layer type 2 empty data frame. */
3409 gsm_modem_upd_via_data(dlci, brk);
3411 } else if (dlci->gsm->encoding == GSM_BASIC_OPT) {
3412 /* Send as MSC control message. */
3413 return gsm_modem_upd_via_msc(dlci, brk);
3416 /* Modem status lines are not supported. */
3417 return -EPROTONOSUPPORT;
3420 static int gsm_carrier_raised(struct tty_port *port)
3422 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
3423 struct gsm_mux *gsm = dlci->gsm;
3425 /* Not yet open so no carrier info */
3426 if (dlci->state != DLCI_OPEN)
3428 if (debug & DBG_CD_ON)
3432 * Basic mode with control channel in ADM mode may not respond
3433 * to CMD_MSC at all and modem_rx is empty.
3435 if (gsm->encoding == GSM_BASIC_OPT &&
3436 gsm->dlci[0]->mode == DLCI_MODE_ADM && !dlci->modem_rx)
3439 return dlci->modem_rx & TIOCM_CD;
3442 static void gsm_dtr_rts(struct tty_port *port, int onoff)
3444 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
3445 unsigned int modem_tx = dlci->modem_tx;
3447 modem_tx |= TIOCM_DTR | TIOCM_RTS;
3449 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
3450 if (modem_tx != dlci->modem_tx) {
3451 dlci->modem_tx = modem_tx;
3452 gsm_modem_update(dlci, 0);
3456 static const struct tty_port_operations gsm_port_ops = {
3457 .carrier_raised = gsm_carrier_raised,
3458 .dtr_rts = gsm_dtr_rts,
3459 .destruct = gsm_dlci_free,
3462 static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty)
3464 struct gsm_mux *gsm;
3465 struct gsm_dlci *dlci;
3466 unsigned int line = tty->index;
3467 unsigned int mux = mux_line_to_num(line);
3475 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
3476 if (gsm_mux[mux] == NULL)
3478 if (line == 0 || line > 61) /* 62/63 reserved */
3483 /* If DLCI 0 is not yet fully open return an error.
3484 This is ok from a locking
3485 perspective as we don't have to worry about this
3487 mutex_lock(&gsm->mutex);
3488 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN) {
3489 mutex_unlock(&gsm->mutex);
3492 dlci = gsm->dlci[line];
3495 dlci = gsm_dlci_alloc(gsm, line);
3498 mutex_unlock(&gsm->mutex);
3501 ret = tty_port_install(&dlci->port, driver, tty);
3505 mutex_unlock(&gsm->mutex);
3510 dlci_get(gsm->dlci[0]);
3512 tty->driver_data = dlci;
3513 mutex_unlock(&gsm->mutex);
3518 static int gsmtty_open(struct tty_struct *tty, struct file *filp)
3520 struct gsm_dlci *dlci = tty->driver_data;
3521 struct tty_port *port = &dlci->port;
3522 struct gsm_mux *gsm = dlci->gsm;
3525 tty_port_tty_set(port, tty);
3528 /* We could in theory open and close before we wait - eg if we get
3529 a DM straight back. This is ok as that will have caused a hangup */
3530 tty_port_set_initialized(port, 1);
3531 /* Start sending off SABM messages */
3533 gsm_dlci_begin_open(dlci);
3535 gsm_dlci_set_opening(dlci);
3536 /* And wait for virtual carrier */
3537 return tty_port_block_til_ready(port, tty, filp);
3540 static void gsmtty_close(struct tty_struct *tty, struct file *filp)
3542 struct gsm_dlci *dlci = tty->driver_data;
3546 if (dlci->state == DLCI_CLOSED)
3548 mutex_lock(&dlci->mutex);
3549 gsm_destroy_network(dlci);
3550 mutex_unlock(&dlci->mutex);
3551 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
3553 gsm_dlci_begin_close(dlci);
3554 if (tty_port_initialized(&dlci->port) && C_HUPCL(tty))
3555 tty_port_lower_dtr_rts(&dlci->port);
3556 tty_port_close_end(&dlci->port, tty);
3557 tty_port_tty_set(&dlci->port, NULL);
3561 static void gsmtty_hangup(struct tty_struct *tty)
3563 struct gsm_dlci *dlci = tty->driver_data;
3564 if (dlci->state == DLCI_CLOSED)
3566 tty_port_hangup(&dlci->port);
3567 gsm_dlci_begin_close(dlci);
3570 static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf,
3574 struct gsm_dlci *dlci = tty->driver_data;
3575 if (dlci->state == DLCI_CLOSED)
3577 /* Stuff the bytes into the fifo queue */
3578 sent = kfifo_in_locked(&dlci->fifo, buf, len, &dlci->lock);
3579 /* Need to kick the channel */
3580 gsm_dlci_data_kick(dlci);
3584 static unsigned int gsmtty_write_room(struct tty_struct *tty)
3586 struct gsm_dlci *dlci = tty->driver_data;
3587 if (dlci->state == DLCI_CLOSED)
3589 return kfifo_avail(&dlci->fifo);
3592 static unsigned int gsmtty_chars_in_buffer(struct tty_struct *tty)
3594 struct gsm_dlci *dlci = tty->driver_data;
3595 if (dlci->state == DLCI_CLOSED)
3597 return kfifo_len(&dlci->fifo);
3600 static void gsmtty_flush_buffer(struct tty_struct *tty)
3602 struct gsm_dlci *dlci = tty->driver_data;
3603 unsigned long flags;
3605 if (dlci->state == DLCI_CLOSED)
3607 /* Caution needed: If we implement reliable transport classes
3608 then the data being transmitted can't simply be junked once
3609 it has first hit the stack. Until then we can just blow it
3611 spin_lock_irqsave(&dlci->lock, flags);
3612 kfifo_reset(&dlci->fifo);
3613 spin_unlock_irqrestore(&dlci->lock, flags);
3614 /* Need to unhook this DLCI from the transmit queue logic */
3617 static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
3619 /* The FIFO handles the queue so the kernel will do the right
3620 thing waiting on chars_in_buffer before calling us. No work
3624 static int gsmtty_tiocmget(struct tty_struct *tty)
3626 struct gsm_dlci *dlci = tty->driver_data;
3627 if (dlci->state == DLCI_CLOSED)
3629 return dlci->modem_rx;
3632 static int gsmtty_tiocmset(struct tty_struct *tty,
3633 unsigned int set, unsigned int clear)
3635 struct gsm_dlci *dlci = tty->driver_data;
3636 unsigned int modem_tx = dlci->modem_tx;
3638 if (dlci->state == DLCI_CLOSED)
3643 if (modem_tx != dlci->modem_tx) {
3644 dlci->modem_tx = modem_tx;
3645 return gsm_modem_update(dlci, 0);
3651 static int gsmtty_ioctl(struct tty_struct *tty,
3652 unsigned int cmd, unsigned long arg)
3654 struct gsm_dlci *dlci = tty->driver_data;
3655 struct gsm_netconfig nc;
3658 if (dlci->state == DLCI_CLOSED)
3661 case GSMIOC_ENABLE_NET:
3662 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc)))
3664 nc.if_name[IFNAMSIZ-1] = '\0';
3665 /* return net interface index or error code */
3666 mutex_lock(&dlci->mutex);
3667 index = gsm_create_network(dlci, &nc);
3668 mutex_unlock(&dlci->mutex);
3669 if (copy_to_user((void __user *)arg, &nc, sizeof(nc)))
3672 case GSMIOC_DISABLE_NET:
3673 if (!capable(CAP_NET_ADMIN))
3675 mutex_lock(&dlci->mutex);
3676 gsm_destroy_network(dlci);
3677 mutex_unlock(&dlci->mutex);
3680 return -ENOIOCTLCMD;
3684 static void gsmtty_set_termios(struct tty_struct *tty,
3685 const struct ktermios *old)
3687 struct gsm_dlci *dlci = tty->driver_data;
3688 if (dlci->state == DLCI_CLOSED)
3690 /* For the moment its fixed. In actual fact the speed information
3691 for the virtual channel can be propogated in both directions by
3692 the RPN control message. This however rapidly gets nasty as we
3693 then have to remap modem signals each way according to whether
3694 our virtual cable is null modem etc .. */
3695 tty_termios_copy_hw(&tty->termios, old);
3698 static void gsmtty_throttle(struct tty_struct *tty)
3700 struct gsm_dlci *dlci = tty->driver_data;
3701 if (dlci->state == DLCI_CLOSED)
3704 dlci->modem_tx &= ~TIOCM_RTS;
3705 dlci->throttled = true;
3706 /* Send an MSC with RTS cleared */
3707 gsm_modem_update(dlci, 0);
3710 static void gsmtty_unthrottle(struct tty_struct *tty)
3712 struct gsm_dlci *dlci = tty->driver_data;
3713 if (dlci->state == DLCI_CLOSED)
3716 dlci->modem_tx |= TIOCM_RTS;
3717 dlci->throttled = false;
3718 /* Send an MSC with RTS set */
3719 gsm_modem_update(dlci, 0);
3722 static int gsmtty_break_ctl(struct tty_struct *tty, int state)
3724 struct gsm_dlci *dlci = tty->driver_data;
3725 int encode = 0; /* Off */
3726 if (dlci->state == DLCI_CLOSED)
3729 if (state == -1) /* "On indefinitely" - we can't encode this
3732 else if (state > 0) {
3733 encode = state / 200; /* mS to encoding */
3735 encode = 0x0F; /* Best effort */
3737 return gsm_modem_update(dlci, encode);
3740 static void gsmtty_cleanup(struct tty_struct *tty)
3742 struct gsm_dlci *dlci = tty->driver_data;
3743 struct gsm_mux *gsm = dlci->gsm;
3746 dlci_put(gsm->dlci[0]);
3750 /* Virtual ttys for the demux */
3751 static const struct tty_operations gsmtty_ops = {
3752 .install = gsmtty_install,
3753 .open = gsmtty_open,
3754 .close = gsmtty_close,
3755 .write = gsmtty_write,
3756 .write_room = gsmtty_write_room,
3757 .chars_in_buffer = gsmtty_chars_in_buffer,
3758 .flush_buffer = gsmtty_flush_buffer,
3759 .ioctl = gsmtty_ioctl,
3760 .throttle = gsmtty_throttle,
3761 .unthrottle = gsmtty_unthrottle,
3762 .set_termios = gsmtty_set_termios,
3763 .hangup = gsmtty_hangup,
3764 .wait_until_sent = gsmtty_wait_until_sent,
3765 .tiocmget = gsmtty_tiocmget,
3766 .tiocmset = gsmtty_tiocmset,
3767 .break_ctl = gsmtty_break_ctl,
3768 .cleanup = gsmtty_cleanup,
3773 static int __init gsm_init(void)
3775 /* Fill in our line protocol discipline, and register it */
3776 int status = tty_register_ldisc(&tty_ldisc_packet);
3778 pr_err("n_gsm: can't register line discipline (err = %d)\n",
3783 gsm_tty_driver = tty_alloc_driver(GSM_TTY_MINORS, TTY_DRIVER_REAL_RAW |
3784 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_HARDWARE_BREAK);
3785 if (IS_ERR(gsm_tty_driver)) {
3786 pr_err("gsm_init: tty allocation failed.\n");
3787 status = PTR_ERR(gsm_tty_driver);
3788 goto err_unreg_ldisc;
3790 gsm_tty_driver->driver_name = "gsmtty";
3791 gsm_tty_driver->name = "gsmtty";
3792 gsm_tty_driver->major = 0; /* Dynamic */
3793 gsm_tty_driver->minor_start = 0;
3794 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
3795 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
3796 gsm_tty_driver->init_termios = tty_std_termios;
3798 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
3799 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
3801 if (tty_register_driver(gsm_tty_driver)) {
3802 pr_err("gsm_init: tty registration failed.\n");
3804 goto err_put_driver;
3806 pr_debug("gsm_init: loaded as %d,%d.\n",
3807 gsm_tty_driver->major, gsm_tty_driver->minor_start);
3810 tty_driver_kref_put(gsm_tty_driver);
3812 tty_unregister_ldisc(&tty_ldisc_packet);
3816 static void __exit gsm_exit(void)
3818 tty_unregister_ldisc(&tty_ldisc_packet);
3819 tty_unregister_driver(gsm_tty_driver);
3820 tty_driver_kref_put(gsm_tty_driver);
3823 module_init(gsm_init);
3824 module_exit(gsm_exit);
3827 MODULE_LICENSE("GPL");
3828 MODULE_ALIAS_LDISC(N_GSM0710);