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 * Mostly done: ioctls for setting modes/timing
10 * Partly done: hooks so you can pull off frames to non tty devs
11 * Restart DLCI 0 when it closes ?
12 * Improve the tx engine
13 * Resolve tx side locking by adding a queue_head and routing
14 * all control traffic via it
15 * General tidy/document
16 * Review the locking/move to refcounts more (mux now moved to an
17 * alloc/free model ready)
18 * Use newest tty open/close port helpers and install hooks
19 * What to do about power functions ?
20 * Termios setting and negotiation
21 * Do we need a 'which mux are you' ioctl to correlate mux and tty sets
25 #include <linux/types.h>
26 #include <linux/major.h>
27 #include <linux/errno.h>
28 #include <linux/signal.h>
29 #include <linux/fcntl.h>
30 #include <linux/sched/signal.h>
31 #include <linux/interrupt.h>
32 #include <linux/tty.h>
33 #include <linux/ctype.h>
35 #include <linux/string.h>
36 #include <linux/slab.h>
37 #include <linux/poll.h>
38 #include <linux/bitops.h>
39 #include <linux/file.h>
40 #include <linux/uaccess.h>
41 #include <linux/module.h>
42 #include <linux/timer.h>
43 #include <linux/tty_flip.h>
44 #include <linux/tty_driver.h>
45 #include <linux/serial.h>
46 #include <linux/kfifo.h>
47 #include <linux/skbuff.h>
50 #include <linux/netdevice.h>
51 #include <linux/etherdevice.h>
52 #include <linux/gsmmux.h>
55 module_param(debug, int, 0600);
57 /* Defaults: these are from the specification */
59 #define T1 10 /* 100mS */
60 #define T2 34 /* 333mS */
61 #define N2 3 /* Retry 3 times */
63 /* Use long timers for testing at low speed with debug on */
70 * Semi-arbitrary buffer size limits. 0710 is normally run with 32-64 byte
71 * limits so this is plenty
75 #define GSM_NET_TX_TIMEOUT (HZ*10)
78 * struct gsm_mux_net - network interface
79 * @struct gsm_dlci* dlci
81 * Created when net interface is initialized.
85 struct gsm_dlci *dlci;
89 * Each block of data we have queued to go out is in the form of
90 * a gsm_msg which holds everything we need in a link layer independent
95 struct list_head list;
96 u8 addr; /* DLCI address + flags */
97 u8 ctrl; /* Control byte + flags */
98 unsigned int len; /* Length of data block (can be zero) */
99 unsigned char *data; /* Points into buffer but not at the start */
100 unsigned char buffer[0];
104 * Each active data link has a gsm_dlci structure associated which ties
105 * the link layer to an optional tty (if the tty side is open). To avoid
106 * complexity right now these are only ever freed up when the mux is
109 * At the moment we don't free DLCI objects until the mux is torn down
110 * this avoid object life time issues but might be worth review later.
117 #define DLCI_CLOSED 0
118 #define DLCI_OPENING 1 /* Sending SABM not seen UA */
119 #define DLCI_OPEN 2 /* SABM/UA complete */
120 #define DLCI_CLOSING 3 /* Sending DISC not seen UA/DM */
125 #define DLCI_MODE_ABM 0 /* Normal Asynchronous Balanced Mode */
126 #define DLCI_MODE_ADM 1 /* Asynchronous Disconnected Mode */
127 spinlock_t lock; /* Protects the internal state */
128 struct timer_list t1; /* Retransmit timer for SABM and UA */
130 /* Uplink tty if active */
131 struct tty_port port; /* The tty bound to this DLCI if there is one */
132 struct kfifo *fifo; /* Queue fifo for the DLCI */
133 struct kfifo _fifo; /* For new fifo API porting only */
134 int adaption; /* Adaption layer in use */
136 u32 modem_rx; /* Our incoming virtual modem lines */
137 u32 modem_tx; /* Our outgoing modem lines */
138 int dead; /* Refuse re-open */
140 int throttled; /* Private copy of throttle state */
141 int constipated; /* Throttle status for outgoing */
143 struct sk_buff *skb; /* Frame being sent */
144 struct sk_buff_head skb_list; /* Queued frames */
145 /* Data handling callback */
146 void (*data)(struct gsm_dlci *dlci, const u8 *data, int len);
147 void (*prev_data)(struct gsm_dlci *dlci, const u8 *data, int len);
148 struct net_device *net; /* network interface, if created */
151 /* DLCI 0, 62/63 are special or reserved see gsmtty_open */
156 * DLCI 0 is used to pass control blocks out of band of the data
157 * flow (and with a higher link priority). One command can be outstanding
158 * at a time and we use this structure to manage them. They are created
159 * and destroyed by the user context, and updated by the receive paths
164 u8 cmd; /* Command we are issuing */
165 u8 *data; /* Data for the command in case we retransmit */
166 int len; /* Length of block for retransmission */
167 int done; /* Done flag */
168 int error; /* Error if any */
172 * Each GSM mux we have is represented by this structure. If we are
173 * operating as an ldisc then we use this structure as our ldisc
174 * state. We need to sort out lifetimes and locking with respect
175 * to the gsm mux array. For now we don't free DLCI objects that
176 * have been instantiated until the mux itself is terminated.
178 * To consider further: tty open versus mux shutdown.
182 struct tty_struct *tty; /* The tty our ldisc is bound to */
188 /* Events on the GSM channel */
189 wait_queue_head_t event;
191 /* Bits for GSM mode decoding */
198 #define GSM_ADDRESS 2
199 #define GSM_CONTROL 3
203 #define GSM_OVERRUN 7
208 unsigned int address;
215 u8 *txframe; /* TX framing buffer */
217 /* Methods for the receiver side */
218 void (*receive)(struct gsm_mux *gsm, u8 ch);
219 void (*error)(struct gsm_mux *gsm, u8 ch, u8 flag);
220 /* And transmit side */
221 int (*output)(struct gsm_mux *mux, u8 *data, int len);
226 int initiator; /* Did we initiate connection */
227 int dead; /* Has the mux been shut down */
228 struct gsm_dlci *dlci[NUM_DLCI];
229 int constipated; /* Asked by remote to shut up */
232 unsigned int tx_bytes; /* TX data outstanding */
233 #define TX_THRESH_HI 8192
234 #define TX_THRESH_LO 2048
235 struct list_head tx_list; /* Pending data packets */
237 /* Control messages */
238 struct timer_list t2_timer; /* Retransmit timer for commands */
239 int cretries; /* Command retry counter */
240 struct gsm_control *pending_cmd;/* Our current pending command */
241 spinlock_t control_lock; /* Protects the pending command */
244 int adaption; /* 1 or 2 supported */
245 u8 ftype; /* UI or UIH */
246 int t1, t2; /* Timers in 1/100th of a sec */
247 int n2; /* Retry count */
249 /* Statistics (not currently exposed) */
250 unsigned long bad_fcs;
251 unsigned long malformed;
252 unsigned long io_error;
253 unsigned long bad_size;
254 unsigned long unsupported;
259 * Mux objects - needed so that we can translate a tty index into the
260 * relevant mux and DLCI.
263 #define MAX_MUX 4 /* 256 minors */
264 static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */
265 static spinlock_t gsm_mux_lock;
267 static struct tty_driver *gsm_tty_driver;
270 * This section of the driver logic implements the GSM encodings
271 * both the basic and the 'advanced'. Reliable transport is not
279 /* I is special: the rest are ..*/
290 /* Channel commands */
292 #define CMD_TEST 0x11
295 #define CMD_FCOFF 0x31
298 #define CMD_FCON 0x51
303 /* Virtual modem bits */
310 #define GSM0_SOF 0xF9
311 #define GSM1_SOF 0x7E
312 #define GSM1_ESCAPE 0x7D
313 #define GSM1_ESCAPE_BITS 0x20
317 static const struct tty_port_operations gsm_port_ops;
320 * CRC table for GSM 0710
323 static const u8 gsm_fcs8[256] = {
324 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75,
325 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B,
326 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69,
327 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67,
328 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D,
329 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43,
330 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51,
331 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F,
332 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05,
333 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B,
334 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19,
335 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17,
336 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D,
337 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33,
338 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21,
339 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F,
340 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95,
341 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B,
342 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89,
343 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87,
344 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD,
345 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3,
346 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1,
347 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF,
348 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5,
349 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB,
350 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9,
351 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7,
352 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD,
353 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3,
354 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1,
355 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF
358 #define INIT_FCS 0xFF
359 #define GOOD_FCS 0xCF
362 * gsm_fcs_add - update FCS
366 * Update the FCS to include c. Uses the algorithm in the specification
370 static inline u8 gsm_fcs_add(u8 fcs, u8 c)
372 return gsm_fcs8[fcs ^ c];
376 * gsm_fcs_add_block - update FCS for a block
379 * @len: length of buffer
381 * Update the FCS to include c. Uses the algorithm in the specification
385 static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len)
388 fcs = gsm_fcs8[fcs ^ *c++];
393 * gsm_read_ea - read a byte into an EA
394 * @val: variable holding value
395 * c: byte going into the EA
397 * Processes one byte of an EA. Updates the passed variable
398 * and returns 1 if the EA is now completely read
401 static int gsm_read_ea(unsigned int *val, u8 c)
403 /* Add the next 7 bits into the value */
406 /* Was this the last byte of the EA 1 = yes*/
411 * gsm_encode_modem - encode modem data bits
412 * @dlci: DLCI to encode from
414 * Returns the correct GSM encoded modem status bits (6 bit field) for
415 * the current status of the DLCI and attached tty object
418 static u8 gsm_encode_modem(const struct gsm_dlci *dlci)
421 /* FC is true flow control not modem bits */
424 if (dlci->modem_tx & TIOCM_DTR)
425 modembits |= MDM_RTC;
426 if (dlci->modem_tx & TIOCM_RTS)
427 modembits |= MDM_RTR;
428 if (dlci->modem_tx & TIOCM_RI)
430 if (dlci->modem_tx & TIOCM_CD)
436 * gsm_print_packet - display a frame for debug
437 * @hdr: header to print before decode
438 * @addr: address EA from the frame
439 * @cr: C/R bit from the frame
440 * @control: control including PF bit
441 * @data: following data bytes
442 * @dlen: length of data
444 * Displays a packet in human readable format for debugging purposes. The
445 * style is based on amateur radio LAP-B dump display.
448 static void gsm_print_packet(const char *hdr, int addr, int cr,
449 u8 control, const u8 *data, int dlen)
454 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]);
456 switch (control & ~PF) {
476 if (!(control & 0x01)) {
477 pr_cont("I N(S)%d N(R)%d",
478 (control & 0x0E) >> 1, (control & 0xE0) >> 5);
479 } else switch (control & 0x0F) {
481 pr_cont("RR(%d)", (control & 0xE0) >> 5);
484 pr_cont("RNR(%d)", (control & 0xE0) >> 5);
487 pr_cont("REJ(%d)", (control & 0xE0) >> 5);
490 pr_cont("[%02X]", control);
506 pr_cont("%02X ", *data++);
515 * Link level transmission side
519 * gsm_stuff_packet - bytestuff a packet
522 * @len: length of input
524 * Expand a buffer by bytestuffing it. The worst case size change
525 * is doubling and the caller is responsible for handing out
526 * suitable sized buffers.
529 static int gsm_stuff_frame(const u8 *input, u8 *output, int len)
533 if (*input == GSM1_SOF || *input == GSM1_ESCAPE
534 || *input == XON || *input == XOFF) {
535 *output++ = GSM1_ESCAPE;
536 *output++ = *input++ ^ GSM1_ESCAPE_BITS;
539 *output++ = *input++;
546 * gsm_send - send a control frame
548 * @addr: address for control frame
549 * @cr: command/response bit
550 * @control: control byte including PF bit
552 * Format up and transmit a control frame. These do not go via the
553 * queueing logic as they should be transmitted ahead of data when
556 * FIXME: Lock versus data TX path
559 static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control)
565 switch (gsm->encoding) {
568 cbuf[1] = (addr << 2) | (cr << 1) | EA;
570 cbuf[3] = EA; /* Length of data = 0 */
571 cbuf[4] = 0xFF - gsm_fcs_add_block(INIT_FCS, cbuf + 1, 3);
577 /* Control frame + packing (but not frame stuffing) in mode 1 */
578 ibuf[0] = (addr << 2) | (cr << 1) | EA;
580 ibuf[2] = 0xFF - gsm_fcs_add_block(INIT_FCS, ibuf, 2);
581 /* Stuffing may double the size worst case */
582 len = gsm_stuff_frame(ibuf, cbuf + 1, 3);
583 /* Now add the SOF markers */
585 cbuf[len + 1] = GSM1_SOF;
586 /* FIXME: we can omit the lead one in many cases */
593 gsm->output(gsm, cbuf, len);
594 gsm_print_packet("-->", addr, cr, control, NULL, 0);
598 * gsm_response - send a control response
600 * @addr: address for control frame
601 * @control: control byte including PF bit
603 * Format up and transmit a link level response frame.
606 static inline void gsm_response(struct gsm_mux *gsm, int addr, int control)
608 gsm_send(gsm, addr, 0, control);
612 * gsm_command - send a control command
614 * @addr: address for control frame
615 * @control: control byte including PF bit
617 * Format up and transmit a link level command frame.
620 static inline void gsm_command(struct gsm_mux *gsm, int addr, int control)
622 gsm_send(gsm, addr, 1, control);
625 /* Data transmission */
627 #define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */
630 * gsm_data_alloc - allocate data frame
632 * @addr: DLCI address
633 * @len: length excluding header and FCS
634 * @ctrl: control byte
636 * Allocate a new data buffer for sending frames with data. Space is left
637 * at the front for header bytes but that is treated as an implementation
638 * detail and not for the high level code to use
641 static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
644 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN,
648 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */
652 INIT_LIST_HEAD(&m->list);
657 * gsm_data_kick - poke the queue
660 * The tty device has called us to indicate that room has appeared in
661 * the transmit queue. Ram more data into the pipe if we have any
662 * If we have been flow-stopped by a CMD_FCOFF, then we can only
663 * send messages on DLCI0 until CMD_FCON
665 * FIXME: lock against link layer control transmissions
668 static void gsm_data_kick(struct gsm_mux *gsm)
670 struct gsm_msg *msg, *nmsg;
674 list_for_each_entry_safe(msg, nmsg, &gsm->tx_list, list) {
675 if (gsm->constipated && msg->addr)
677 if (gsm->encoding != 0) {
678 gsm->txframe[0] = GSM1_SOF;
679 len = gsm_stuff_frame(msg->data,
680 gsm->txframe + 1, msg->len);
681 gsm->txframe[len + 1] = GSM1_SOF;
684 gsm->txframe[0] = GSM0_SOF;
685 memcpy(gsm->txframe + 1 , msg->data, msg->len);
686 gsm->txframe[msg->len + 1] = GSM0_SOF;
691 print_hex_dump_bytes("gsm_data_kick: ",
695 if (gsm->output(gsm, gsm->txframe + skip_sof,
698 /* FIXME: Can eliminate one SOF in many more cases */
699 gsm->tx_bytes -= msg->len;
700 /* For a burst of frames skip the extra SOF within the
704 list_del(&msg->list);
710 * __gsm_data_queue - queue a UI or UIH frame
711 * @dlci: DLCI sending the data
712 * @msg: message queued
714 * Add data to the transmit queue and try and get stuff moving
715 * out of the mux tty if not already doing so. The Caller must hold
719 static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
721 struct gsm_mux *gsm = dlci->gsm;
723 u8 *fcs = dp + msg->len;
725 /* Fill in the header */
726 if (gsm->encoding == 0) {
728 *--dp = (msg->len << 1) | EA;
730 *--dp = (msg->len >> 7); /* bits 7 - 15 */
731 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */
737 *--dp = (msg->addr << 2) | 2 | EA;
739 *--dp = (msg->addr << 2) | EA;
740 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp);
741 /* Ugly protocol layering violation */
742 if (msg->ctrl == UI || msg->ctrl == (UI|PF))
743 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len);
746 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl,
747 msg->data, msg->len);
749 /* Move the header back and adjust the length, also allow for the FCS
750 now tacked on the end */
751 msg->len += (msg->data - dp) + 1;
754 /* Add to the actual output queue */
755 list_add_tail(&msg->list, &gsm->tx_list);
756 gsm->tx_bytes += msg->len;
761 * gsm_data_queue - queue a UI or UIH frame
762 * @dlci: DLCI sending the data
763 * @msg: message queued
765 * Add data to the transmit queue and try and get stuff moving
766 * out of the mux tty if not already doing so. Take the
767 * the gsm tx lock and dlci lock.
770 static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
773 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
774 __gsm_data_queue(dlci, msg);
775 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
779 * gsm_dlci_data_output - try and push data out of a DLCI
781 * @dlci: the DLCI to pull data from
783 * Pull data from a DLCI and send it into the transmit queue if there
784 * is data. Keep to the MRU of the mux. This path handles the usual tty
785 * interface which is a byte stream with optional modem data.
787 * Caller must hold the tx_lock of the mux.
790 static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci)
794 int len, total_size, size;
795 int h = dlci->adaption - 1;
799 len = kfifo_len(dlci->fifo);
803 /* MTU/MRU count only the data bits */
809 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
810 /* FIXME: need a timer or something to kick this so it can't
811 get stuck with no work outstanding and no buffer free */
815 switch (dlci->adaption) {
816 case 1: /* Unstructured */
818 case 2: /* Unstructed with modem bits.
819 Always one byte as we never send inline break data */
820 *dp++ = gsm_encode_modem(dlci);
823 WARN_ON(kfifo_out_locked(dlci->fifo, dp , len, &dlci->lock) != len);
824 __gsm_data_queue(dlci, msg);
827 /* Bytes of data we used up */
832 * gsm_dlci_data_output_framed - try and push data out of a DLCI
834 * @dlci: the DLCI to pull data from
836 * Pull data from a DLCI and send it into the transmit queue if there
837 * is data. Keep to the MRU of the mux. This path handles framed data
838 * queued as skbuffs to the DLCI.
840 * Caller must hold the tx_lock of the mux.
843 static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
844 struct gsm_dlci *dlci)
849 int last = 0, first = 0;
852 /* One byte per frame is used for B/F flags */
853 if (dlci->adaption == 4)
856 /* dlci->skb is locked by tx_lock */
857 if (dlci->skb == NULL) {
858 dlci->skb = skb_dequeue_tail(&dlci->skb_list);
859 if (dlci->skb == NULL)
863 len = dlci->skb->len + overhead;
865 /* MTU/MRU count only the data bits */
866 if (len > gsm->mtu) {
867 if (dlci->adaption == 3) {
868 /* Over long frame, bin it */
869 dev_kfree_skb_any(dlci->skb);
877 size = len + overhead;
878 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
880 /* FIXME: need a timer or something to kick this so it can't
881 get stuck with no work outstanding and no buffer free */
883 skb_queue_tail(&dlci->skb_list, dlci->skb);
889 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */
890 /* Flag byte to carry the start/end info */
891 *dp++ = last << 7 | first << 6 | 1; /* EA */
894 memcpy(dp, dlci->skb->data, len);
895 skb_pull(dlci->skb, len);
896 __gsm_data_queue(dlci, msg);
898 dev_kfree_skb_any(dlci->skb);
905 * gsm_dlci_data_sweep - look for data to send
908 * Sweep the GSM mux channels in priority order looking for ones with
909 * data to send. We could do with optimising this scan a bit. We aim
910 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit
911 * TX_THRESH_LO we get called again
913 * FIXME: We should round robin between groups and in theory you can
914 * renegotiate DLCI priorities with optional stuff. Needs optimising.
917 static void gsm_dlci_data_sweep(struct gsm_mux *gsm)
920 /* Priority ordering: We should do priority with RR of the groups */
923 while (i < NUM_DLCI) {
924 struct gsm_dlci *dlci;
926 if (gsm->tx_bytes > TX_THRESH_HI)
929 if (dlci == NULL || dlci->constipated) {
933 if (dlci->adaption < 3 && !dlci->net)
934 len = gsm_dlci_data_output(gsm, dlci);
936 len = gsm_dlci_data_output_framed(gsm, dlci);
939 /* DLCI empty - try the next */
946 * gsm_dlci_data_kick - transmit if possible
947 * @dlci: DLCI to kick
949 * Transmit data from this DLCI if the queue is empty. We can't rely on
950 * a tty wakeup except when we filled the pipe so we need to fire off
951 * new data ourselves in other cases.
954 static void gsm_dlci_data_kick(struct gsm_dlci *dlci)
959 if (dlci->constipated)
962 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
963 /* If we have nothing running then we need to fire up */
964 sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO);
965 if (dlci->gsm->tx_bytes == 0) {
967 gsm_dlci_data_output_framed(dlci->gsm, dlci);
969 gsm_dlci_data_output(dlci->gsm, dlci);
972 gsm_dlci_data_sweep(dlci->gsm);
973 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
977 * Control message processing
982 * gsm_control_reply - send a response frame to a control
984 * @cmd: the command to use
985 * @data: data to follow encoded info
986 * @dlen: length of data
988 * Encode up and queue a UI/UIH frame containing our response.
991 static void gsm_control_reply(struct gsm_mux *gsm, int cmd, const u8 *data,
995 msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype);
998 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */
999 msg->data[1] = (dlen << 1) | EA;
1000 memcpy(msg->data + 2, data, dlen);
1001 gsm_data_queue(gsm->dlci[0], msg);
1005 * gsm_process_modem - process received modem status
1006 * @tty: virtual tty bound to the DLCI
1007 * @dlci: DLCI to affect
1008 * @modem: modem bits (full EA)
1010 * Used when a modem control message or line state inline in adaption
1011 * layer 2 is processed. Sort out the local modem state and throttles
1014 static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
1015 u32 modem, int clen)
1021 /* The modem status command can either contain one octet (v.24 signals)
1022 or two octets (v.24 signals + break signals). The length field will
1023 either be 2 or 3 respectively. This is specified in section
1024 5.4.6.3.7 of the 27.010 mux spec. */
1027 modem = modem & 0x7f;
1030 modem = (modem >> 7) & 0x7f;
1033 /* Flow control/ready to communicate */
1034 fc = (modem & MDM_FC) || !(modem & MDM_RTR);
1035 if (fc && !dlci->constipated) {
1036 /* Need to throttle our output on this device */
1037 dlci->constipated = 1;
1038 } else if (!fc && dlci->constipated) {
1039 dlci->constipated = 0;
1040 gsm_dlci_data_kick(dlci);
1043 /* Map modem bits */
1044 if (modem & MDM_RTC)
1045 mlines |= TIOCM_DSR | TIOCM_DTR;
1046 if (modem & MDM_RTR)
1047 mlines |= TIOCM_RTS | TIOCM_CTS;
1053 /* Carrier drop -> hangup */
1055 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD))
1060 tty_insert_flip_char(&dlci->port, 0, TTY_BREAK);
1061 dlci->modem_rx = mlines;
1065 * gsm_control_modem - modem status received
1067 * @data: data following command
1068 * @clen: command length
1070 * We have received a modem status control message. This is used by
1071 * the GSM mux protocol to pass virtual modem line status and optionally
1072 * to indicate break signals. Unpack it, convert to Linux representation
1073 * and if need be stuff a break message down the tty.
1076 static void gsm_control_modem(struct gsm_mux *gsm, const u8 *data, int clen)
1078 unsigned int addr = 0;
1079 unsigned int modem = 0;
1080 unsigned int brk = 0;
1081 struct gsm_dlci *dlci;
1083 const u8 *dp = data;
1084 struct tty_struct *tty;
1086 while (gsm_read_ea(&addr, *dp++) == 0) {
1091 /* Must be at least one byte following the EA */
1097 /* Closed port, or invalid ? */
1098 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1100 dlci = gsm->dlci[addr];
1102 while (gsm_read_ea(&modem, *dp++) == 0) {
1109 while (gsm_read_ea(&brk, *dp++) == 0) {
1115 modem |= (brk & 0x7f);
1117 tty = tty_port_tty_get(&dlci->port);
1118 gsm_process_modem(tty, dlci, modem, clen);
1123 gsm_control_reply(gsm, CMD_MSC, data, clen);
1127 * gsm_control_rls - remote line status
1130 * @clen: data length
1132 * The modem sends us a two byte message on the control channel whenever
1133 * it wishes to send us an error state from the virtual link. Stuff
1134 * this into the uplink tty if present
1137 static void gsm_control_rls(struct gsm_mux *gsm, const u8 *data, int clen)
1139 struct tty_port *port;
1140 unsigned int addr = 0;
1143 const u8 *dp = data;
1145 while (gsm_read_ea(&addr, *dp++) == 0) {
1150 /* Must be at least one byte following ea */
1155 /* Closed port, or invalid ? */
1156 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1160 if ((bits & 1) == 0)
1163 port = &gsm->dlci[addr]->port;
1166 tty_insert_flip_char(port, 0, TTY_OVERRUN);
1168 tty_insert_flip_char(port, 0, TTY_PARITY);
1170 tty_insert_flip_char(port, 0, TTY_FRAME);
1172 tty_flip_buffer_push(port);
1174 gsm_control_reply(gsm, CMD_RLS, data, clen);
1177 static void gsm_dlci_begin_close(struct gsm_dlci *dlci);
1180 * gsm_control_message - DLCI 0 control processing
1182 * @command: the command EA
1183 * @data: data beyond the command/length EAs
1186 * Input processor for control messages from the other end of the link.
1187 * Processes the incoming request and queues a response frame or an
1188 * NSC response if not supported
1191 static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
1192 const u8 *data, int clen)
1195 unsigned long flags;
1199 struct gsm_dlci *dlci = gsm->dlci[0];
1200 /* Modem wishes to close down */
1204 gsm_dlci_begin_close(dlci);
1209 /* Modem wishes to test, reply with the data */
1210 gsm_control_reply(gsm, CMD_TEST, data, clen);
1213 /* Modem can accept data again */
1214 gsm->constipated = 0;
1215 gsm_control_reply(gsm, CMD_FCON, NULL, 0);
1216 /* Kick the link in case it is idling */
1217 spin_lock_irqsave(&gsm->tx_lock, flags);
1219 spin_unlock_irqrestore(&gsm->tx_lock, flags);
1222 /* Modem wants us to STFU */
1223 gsm->constipated = 1;
1224 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0);
1227 /* Out of band modem line change indicator for a DLCI */
1228 gsm_control_modem(gsm, data, clen);
1231 /* Out of band error reception for a DLCI */
1232 gsm_control_rls(gsm, data, clen);
1235 /* Modem wishes to enter power saving state */
1236 gsm_control_reply(gsm, CMD_PSC, NULL, 0);
1238 /* Optional unsupported commands */
1239 case CMD_PN: /* Parameter negotiation */
1240 case CMD_RPN: /* Remote port negotiation */
1241 case CMD_SNC: /* Service negotiation command */
1243 /* Reply to bad commands with an NSC */
1245 gsm_control_reply(gsm, CMD_NSC, buf, 1);
1251 * gsm_control_response - process a response to our control
1253 * @command: the command (response) EA
1254 * @data: data beyond the command/length EA
1257 * Process a response to an outstanding command. We only allow a single
1258 * control message in flight so this is fairly easy. All the clean up
1259 * is done by the caller, we just update the fields, flag it as done
1263 static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
1264 const u8 *data, int clen)
1266 struct gsm_control *ctrl;
1267 unsigned long flags;
1269 spin_lock_irqsave(&gsm->control_lock, flags);
1271 ctrl = gsm->pending_cmd;
1272 /* Does the reply match our command */
1274 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) {
1275 /* Our command was replied to, kill the retry timer */
1276 del_timer(&gsm->t2_timer);
1277 gsm->pending_cmd = NULL;
1278 /* Rejected by the other end */
1279 if (command == CMD_NSC)
1280 ctrl->error = -EOPNOTSUPP;
1282 wake_up(&gsm->event);
1284 spin_unlock_irqrestore(&gsm->control_lock, flags);
1288 * gsm_control_transmit - send control packet
1290 * @ctrl: frame to send
1292 * Send out a pending control command (called under control lock)
1295 static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl)
1297 struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, gsm->ftype);
1300 msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */
1301 memcpy(msg->data + 1, ctrl->data, ctrl->len);
1302 gsm_data_queue(gsm->dlci[0], msg);
1306 * gsm_control_retransmit - retransmit a control frame
1307 * @data: pointer to our gsm object
1309 * Called off the T2 timer expiry in order to retransmit control frames
1310 * that have been lost in the system somewhere. The control_lock protects
1311 * us from colliding with another sender or a receive completion event.
1312 * In that situation the timer may still occur in a small window but
1313 * gsm->pending_cmd will be NULL and we just let the timer expire.
1316 static void gsm_control_retransmit(struct timer_list *t)
1318 struct gsm_mux *gsm = from_timer(gsm, t, t2_timer);
1319 struct gsm_control *ctrl;
1320 unsigned long flags;
1321 spin_lock_irqsave(&gsm->control_lock, flags);
1322 ctrl = gsm->pending_cmd;
1325 if (gsm->cretries == 0) {
1326 gsm->pending_cmd = NULL;
1327 ctrl->error = -ETIMEDOUT;
1329 spin_unlock_irqrestore(&gsm->control_lock, flags);
1330 wake_up(&gsm->event);
1333 gsm_control_transmit(gsm, ctrl);
1334 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1336 spin_unlock_irqrestore(&gsm->control_lock, flags);
1340 * gsm_control_send - send a control frame on DLCI 0
1341 * @gsm: the GSM channel
1342 * @command: command to send including CR bit
1343 * @data: bytes of data (must be kmalloced)
1344 * @len: length of the block to send
1346 * Queue and dispatch a control command. Only one command can be
1347 * active at a time. In theory more can be outstanding but the matching
1348 * gets really complicated so for now stick to one outstanding.
1351 static struct gsm_control *gsm_control_send(struct gsm_mux *gsm,
1352 unsigned int command, u8 *data, int clen)
1354 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control),
1356 unsigned long flags;
1360 wait_event(gsm->event, gsm->pending_cmd == NULL);
1361 spin_lock_irqsave(&gsm->control_lock, flags);
1362 if (gsm->pending_cmd != NULL) {
1363 spin_unlock_irqrestore(&gsm->control_lock, flags);
1366 ctrl->cmd = command;
1369 gsm->pending_cmd = ctrl;
1371 /* If DLCI0 is in ADM mode skip retries, it won't respond */
1372 if (gsm->dlci[0]->mode == DLCI_MODE_ADM)
1375 gsm->cretries = gsm->n2;
1377 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1378 gsm_control_transmit(gsm, ctrl);
1379 spin_unlock_irqrestore(&gsm->control_lock, flags);
1384 * gsm_control_wait - wait for a control to finish
1386 * @control: control we are waiting on
1388 * Waits for the control to complete or time out. Frees any used
1389 * resources and returns 0 for success, or an error if the remote
1390 * rejected or ignored the request.
1393 static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
1396 wait_event(gsm->event, control->done == 1);
1397 err = control->error;
1404 * DLCI level handling: Needs krefs
1408 * State transitions and timers
1412 * gsm_dlci_close - a DLCI has closed
1413 * @dlci: DLCI that closed
1415 * Perform processing when moving a DLCI into closed state. If there
1416 * is an attached tty this is hung up
1419 static void gsm_dlci_close(struct gsm_dlci *dlci)
1421 del_timer(&dlci->t1);
1423 pr_debug("DLCI %d goes closed.\n", dlci->addr);
1424 dlci->state = DLCI_CLOSED;
1425 if (dlci->addr != 0) {
1426 tty_port_tty_hangup(&dlci->port, false);
1427 kfifo_reset(dlci->fifo);
1429 dlci->gsm->dead = 1;
1430 wake_up(&dlci->gsm->event);
1431 /* A DLCI 0 close is a MUX termination so we need to kick that
1432 back to userspace somehow */
1436 * gsm_dlci_open - a DLCI has opened
1437 * @dlci: DLCI that opened
1439 * Perform processing when moving a DLCI into open state.
1442 static void gsm_dlci_open(struct gsm_dlci *dlci)
1444 /* Note that SABM UA .. SABM UA first UA lost can mean that we go
1446 del_timer(&dlci->t1);
1447 /* This will let a tty open continue */
1448 dlci->state = DLCI_OPEN;
1450 pr_debug("DLCI %d goes open.\n", dlci->addr);
1451 wake_up(&dlci->gsm->event);
1455 * gsm_dlci_t1 - T1 timer expiry
1456 * @dlci: DLCI that opened
1458 * The T1 timer handles retransmits of control frames (essentially of
1459 * SABM and DISC). We resend the command until the retry count runs out
1460 * in which case an opening port goes back to closed and a closing port
1461 * is simply put into closed state (any further frames from the other
1462 * end will get a DM response)
1464 * Some control dlci can stay in ADM mode with other dlci working just
1465 * fine. In that case we can just keep the control dlci open after the
1466 * DLCI_OPENING retries time out.
1469 static void gsm_dlci_t1(struct timer_list *t)
1471 struct gsm_dlci *dlci = from_timer(dlci, t, t1);
1472 struct gsm_mux *gsm = dlci->gsm;
1474 switch (dlci->state) {
1477 if (dlci->retries) {
1478 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1479 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1480 } else if (!dlci->addr && gsm->control == (DM | PF)) {
1482 pr_info("DLCI %d opening in ADM mode.\n",
1484 dlci->mode = DLCI_MODE_ADM;
1485 gsm_dlci_open(dlci);
1487 gsm_dlci_close(dlci);
1493 if (dlci->retries) {
1494 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1495 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1497 gsm_dlci_close(dlci);
1503 * gsm_dlci_begin_open - start channel open procedure
1504 * @dlci: DLCI to open
1506 * Commence opening a DLCI from the Linux side. We issue SABM messages
1507 * to the modem which should then reply with a UA or ADM, at which point
1508 * we will move into open state. Opening is done asynchronously with retry
1509 * running off timers and the responses.
1512 static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
1514 struct gsm_mux *gsm = dlci->gsm;
1515 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING)
1517 dlci->retries = gsm->n2;
1518 dlci->state = DLCI_OPENING;
1519 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1520 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1524 * gsm_dlci_begin_close - start channel open procedure
1525 * @dlci: DLCI to open
1527 * Commence closing a DLCI from the Linux side. We issue DISC messages
1528 * to the modem which should then reply with a UA, at which point we
1529 * will move into closed state. Closing is done asynchronously with retry
1530 * off timers. We may also receive a DM reply from the other end which
1531 * indicates the channel was already closed.
1534 static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
1536 struct gsm_mux *gsm = dlci->gsm;
1537 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
1539 dlci->retries = gsm->n2;
1540 dlci->state = DLCI_CLOSING;
1541 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1542 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1546 * gsm_dlci_data - data arrived
1548 * @data: block of bytes received
1549 * @len: length of received block
1551 * A UI or UIH frame has arrived which contains data for a channel
1552 * other than the control channel. If the relevant virtual tty is
1553 * open we shovel the bits down it, if not we drop them.
1556 static void gsm_dlci_data(struct gsm_dlci *dlci, const u8 *data, int clen)
1559 struct tty_port *port = &dlci->port;
1560 struct tty_struct *tty;
1561 unsigned int modem = 0;
1565 pr_debug("%d bytes for tty\n", len);
1566 switch (dlci->adaption) {
1567 /* Unsupported types */
1568 case 4: /* Packetised interruptible data */
1570 case 3: /* Packetised uininterruptible voice/data */
1572 case 2: /* Asynchronous serial with line state in each frame */
1573 while (gsm_read_ea(&modem, *data++) == 0) {
1578 tty = tty_port_tty_get(port);
1580 gsm_process_modem(tty, dlci, modem, clen);
1584 case 1: /* Line state will go via DLCI 0 controls only */
1586 tty_insert_flip_string(port, data, len);
1587 tty_flip_buffer_push(port);
1592 * gsm_dlci_control - data arrived on control channel
1594 * @data: block of bytes received
1595 * @len: length of received block
1597 * A UI or UIH frame has arrived which contains data for DLCI 0 the
1598 * control channel. This should contain a command EA followed by
1599 * control data bytes. The command EA contains a command/response bit
1600 * and we divide up the work accordingly.
1603 static void gsm_dlci_command(struct gsm_dlci *dlci, const u8 *data, int len)
1605 /* See what command is involved */
1606 unsigned int command = 0;
1608 if (gsm_read_ea(&command, *data++) == 1) {
1611 /* FIXME: this is properly an EA */
1613 /* Malformed command ? */
1617 gsm_control_message(dlci->gsm, command,
1620 gsm_control_response(dlci->gsm, command,
1628 * Allocate/Free DLCI channels
1632 * gsm_dlci_alloc - allocate a DLCI
1634 * @addr: address of the DLCI
1636 * Allocate and install a new DLCI object into the GSM mux.
1638 * FIXME: review locking races
1641 static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
1643 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC);
1646 spin_lock_init(&dlci->lock);
1647 mutex_init(&dlci->mutex);
1648 dlci->fifo = &dlci->_fifo;
1649 if (kfifo_alloc(&dlci->_fifo, 4096, GFP_KERNEL) < 0) {
1654 skb_queue_head_init(&dlci->skb_list);
1655 timer_setup(&dlci->t1, gsm_dlci_t1, 0);
1656 tty_port_init(&dlci->port);
1657 dlci->port.ops = &gsm_port_ops;
1660 dlci->adaption = gsm->adaption;
1661 dlci->state = DLCI_CLOSED;
1663 dlci->data = gsm_dlci_data;
1665 dlci->data = gsm_dlci_command;
1666 gsm->dlci[addr] = dlci;
1671 * gsm_dlci_free - free DLCI
1672 * @dlci: DLCI to free
1678 static void gsm_dlci_free(struct tty_port *port)
1680 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
1682 del_timer_sync(&dlci->t1);
1683 dlci->gsm->dlci[dlci->addr] = NULL;
1684 tty_port_destroy(&dlci->port);
1685 kfifo_free(dlci->fifo);
1686 while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
1687 dev_kfree_skb(dlci->skb);
1691 static inline void dlci_get(struct gsm_dlci *dlci)
1693 tty_port_get(&dlci->port);
1696 static inline void dlci_put(struct gsm_dlci *dlci)
1698 tty_port_put(&dlci->port);
1701 static void gsm_destroy_network(struct gsm_dlci *dlci);
1704 * gsm_dlci_release - release DLCI
1705 * @dlci: DLCI to destroy
1707 * Release a DLCI. Actual free is deferred until either
1708 * mux is closed or tty is closed - whichever is last.
1712 static void gsm_dlci_release(struct gsm_dlci *dlci)
1714 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1716 mutex_lock(&dlci->mutex);
1717 gsm_destroy_network(dlci);
1718 mutex_unlock(&dlci->mutex);
1722 tty_port_tty_set(&dlci->port, NULL);
1725 dlci->state = DLCI_CLOSED;
1730 * LAPBish link layer logic
1734 * gsm_queue - a GSM frame is ready to process
1735 * @gsm: pointer to our gsm mux
1737 * At this point in time a frame has arrived and been demangled from
1738 * the line encoding. All the differences between the encodings have
1739 * been handled below us and the frame is unpacked into the structures.
1740 * The fcs holds the header FCS but any data FCS must be added here.
1743 static void gsm_queue(struct gsm_mux *gsm)
1745 struct gsm_dlci *dlci;
1748 /* We have to sneak a look at the packet body to do the FCS.
1749 A somewhat layering violation in the spec */
1751 if ((gsm->control & ~PF) == UI)
1752 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len);
1753 if (gsm->encoding == 0) {
1754 /* WARNING: gsm->received_fcs is used for
1755 gsm->encoding = 0 only.
1756 In this case it contain the last piece of data
1757 required to generate final CRC */
1758 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs);
1760 if (gsm->fcs != GOOD_FCS) {
1763 pr_debug("BAD FCS %02x\n", gsm->fcs);
1766 address = gsm->address >> 1;
1767 if (address >= NUM_DLCI)
1770 cr = gsm->address & 1; /* C/R bit */
1772 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
1774 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */
1775 dlci = gsm->dlci[address];
1777 switch (gsm->control) {
1782 dlci = gsm_dlci_alloc(gsm, address);
1786 gsm_response(gsm, address, DM);
1788 gsm_response(gsm, address, UA);
1789 gsm_dlci_open(dlci);
1795 if (dlci == NULL || dlci->state == DLCI_CLOSED) {
1796 gsm_response(gsm, address, DM);
1799 /* Real close complete */
1800 gsm_response(gsm, address, UA);
1801 gsm_dlci_close(dlci);
1805 if (cr == 0 || dlci == NULL)
1807 switch (dlci->state) {
1809 gsm_dlci_close(dlci);
1812 gsm_dlci_open(dlci);
1816 case DM: /* DM can be valid unsolicited */
1822 gsm_dlci_close(dlci);
1832 if (dlci == NULL || dlci->state != DLCI_OPEN) {
1833 gsm_command(gsm, address, DM|PF);
1836 dlci->data(dlci, gsm->buf, gsm->len);
1849 * gsm0_receive - perform processing for non-transparency
1850 * @gsm: gsm data for this ldisc instance
1853 * Receive bytes in gsm mode 0
1856 static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
1860 switch (gsm->state) {
1861 case GSM_SEARCH: /* SOF marker */
1862 if (c == GSM0_SOF) {
1863 gsm->state = GSM_ADDRESS;
1866 gsm->fcs = INIT_FCS;
1869 case GSM_ADDRESS: /* Address EA */
1870 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1871 if (gsm_read_ea(&gsm->address, c))
1872 gsm->state = GSM_CONTROL;
1874 case GSM_CONTROL: /* Control Byte */
1875 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1877 gsm->state = GSM_LEN0;
1879 case GSM_LEN0: /* Length EA */
1880 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1881 if (gsm_read_ea(&gsm->len, c)) {
1882 if (gsm->len > gsm->mru) {
1884 gsm->state = GSM_SEARCH;
1889 gsm->state = GSM_FCS;
1891 gsm->state = GSM_DATA;
1894 gsm->state = GSM_LEN1;
1897 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1899 gsm->len |= len << 7;
1900 if (gsm->len > gsm->mru) {
1902 gsm->state = GSM_SEARCH;
1907 gsm->state = GSM_FCS;
1909 gsm->state = GSM_DATA;
1911 case GSM_DATA: /* Data */
1912 gsm->buf[gsm->count++] = c;
1913 if (gsm->count == gsm->len)
1914 gsm->state = GSM_FCS;
1916 case GSM_FCS: /* FCS follows the packet */
1917 gsm->received_fcs = c;
1919 gsm->state = GSM_SSOF;
1922 if (c == GSM0_SOF) {
1923 gsm->state = GSM_SEARCH;
1931 * gsm1_receive - perform processing for non-transparency
1932 * @gsm: gsm data for this ldisc instance
1935 * Receive bytes in mode 1 (Advanced option)
1938 static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
1940 if (c == GSM1_SOF) {
1941 /* EOF is only valid in frame if we have got to the data state
1942 and received at least one byte (the FCS) */
1943 if (gsm->state == GSM_DATA && gsm->count) {
1944 /* Extract the FCS */
1946 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
1947 gsm->len = gsm->count;
1949 gsm->state = GSM_START;
1952 /* Any partial frame was a runt so go back to start */
1953 if (gsm->state != GSM_START) {
1955 gsm->state = GSM_START;
1957 /* A SOF in GSM_START means we are still reading idling or
1962 if (c == GSM1_ESCAPE) {
1967 /* Only an unescaped SOF gets us out of GSM search */
1968 if (gsm->state == GSM_SEARCH)
1972 c ^= GSM1_ESCAPE_BITS;
1975 switch (gsm->state) {
1976 case GSM_START: /* First byte after SOF */
1978 gsm->state = GSM_ADDRESS;
1979 gsm->fcs = INIT_FCS;
1981 case GSM_ADDRESS: /* Address continuation */
1982 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1983 if (gsm_read_ea(&gsm->address, c))
1984 gsm->state = GSM_CONTROL;
1986 case GSM_CONTROL: /* Control Byte */
1987 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1990 gsm->state = GSM_DATA;
1992 case GSM_DATA: /* Data */
1993 if (gsm->count > gsm->mru) { /* Allow one for the FCS */
1994 gsm->state = GSM_OVERRUN;
1997 gsm->buf[gsm->count++] = c;
1999 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */
2005 * gsm_error - handle tty error
2007 * @data: byte received (may be invalid)
2008 * @flag: error received
2010 * Handle an error in the receipt of data for a frame. Currently we just
2011 * go back to hunting for a SOF.
2013 * FIXME: better diagnostics ?
2016 static void gsm_error(struct gsm_mux *gsm,
2017 unsigned char data, unsigned char flag)
2019 gsm->state = GSM_SEARCH;
2023 static int gsm_disconnect(struct gsm_mux *gsm)
2025 struct gsm_dlci *dlci = gsm->dlci[0];
2026 struct gsm_control *gc;
2031 /* In theory disconnecting DLCI 0 is sufficient but for some
2032 modems this is apparently not the case. */
2033 gc = gsm_control_send(gsm, CMD_CLD, NULL, 0);
2035 gsm_control_wait(gsm, gc);
2037 del_timer_sync(&gsm->t2_timer);
2038 /* Now we are sure T2 has stopped */
2040 gsm_dlci_begin_close(dlci);
2041 wait_event_interruptible(gsm->event,
2042 dlci->state == DLCI_CLOSED);
2044 if (signal_pending(current))
2051 * gsm_cleanup_mux - generic GSM protocol cleanup
2054 * Clean up the bits of the mux which are the same for all framing
2055 * protocols. Remove the mux from the mux table, stop all the timers
2056 * and then shut down each device hanging up the channels as we go.
2059 static void gsm_cleanup_mux(struct gsm_mux *gsm)
2062 struct gsm_dlci *dlci = gsm->dlci[0];
2063 struct gsm_msg *txq, *ntxq;
2067 spin_lock(&gsm_mux_lock);
2068 for (i = 0; i < MAX_MUX; i++) {
2069 if (gsm_mux[i] == gsm) {
2074 spin_unlock(&gsm_mux_lock);
2075 /* open failed before registering => nothing to do */
2079 del_timer_sync(&gsm->t2_timer);
2080 /* Now we are sure T2 has stopped */
2084 /* Free up any link layer users */
2085 mutex_lock(&gsm->mutex);
2086 for (i = 0; i < NUM_DLCI; i++)
2088 gsm_dlci_release(gsm->dlci[i]);
2089 mutex_unlock(&gsm->mutex);
2090 /* Now wipe the queues */
2091 list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list)
2093 INIT_LIST_HEAD(&gsm->tx_list);
2097 * gsm_activate_mux - generic GSM setup
2100 * Set up the bits of the mux which are the same for all framing
2101 * protocols. Add the mux to the mux table so it can be opened and
2102 * finally kick off connecting to DLCI 0 on the modem.
2105 static int gsm_activate_mux(struct gsm_mux *gsm)
2107 struct gsm_dlci *dlci;
2110 timer_setup(&gsm->t2_timer, gsm_control_retransmit, 0);
2111 init_waitqueue_head(&gsm->event);
2112 spin_lock_init(&gsm->control_lock);
2113 spin_lock_init(&gsm->tx_lock);
2115 if (gsm->encoding == 0)
2116 gsm->receive = gsm0_receive;
2118 gsm->receive = gsm1_receive;
2119 gsm->error = gsm_error;
2121 spin_lock(&gsm_mux_lock);
2122 for (i = 0; i < MAX_MUX; i++) {
2123 if (gsm_mux[i] == NULL) {
2129 spin_unlock(&gsm_mux_lock);
2133 dlci = gsm_dlci_alloc(gsm, 0);
2136 gsm->dead = 0; /* Tty opens are now permissible */
2141 * gsm_free_mux - free up a mux
2144 * Dispose of allocated resources for a dead mux
2146 static void gsm_free_mux(struct gsm_mux *gsm)
2148 kfree(gsm->txframe);
2154 * gsm_free_muxr - free up a mux
2157 * Dispose of allocated resources for a dead mux
2159 static void gsm_free_muxr(struct kref *ref)
2161 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref);
2165 static inline void mux_get(struct gsm_mux *gsm)
2167 kref_get(&gsm->ref);
2170 static inline void mux_put(struct gsm_mux *gsm)
2172 kref_put(&gsm->ref, gsm_free_muxr);
2175 static inline unsigned int mux_num_to_base(struct gsm_mux *gsm)
2177 return gsm->num * NUM_DLCI;
2180 static inline unsigned int mux_line_to_num(unsigned int line)
2182 return line / NUM_DLCI;
2186 * gsm_alloc_mux - allocate a mux
2188 * Creates a new mux ready for activation.
2191 static struct gsm_mux *gsm_alloc_mux(void)
2193 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
2196 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL);
2197 if (gsm->buf == NULL) {
2201 gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL);
2202 if (gsm->txframe == NULL) {
2207 spin_lock_init(&gsm->lock);
2208 mutex_init(&gsm->mutex);
2209 kref_init(&gsm->ref);
2210 INIT_LIST_HEAD(&gsm->tx_list);
2218 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
2220 gsm->dead = 1; /* Avoid early tty opens */
2225 static void gsm_copy_config_values(struct gsm_mux *gsm,
2226 struct gsm_config *c)
2228 memset(c, 0, sizeof(*c));
2229 c->adaption = gsm->adaption;
2230 c->encapsulation = gsm->encoding;
2231 c->initiator = gsm->initiator;
2234 c->t3 = 0; /* Not supported */
2236 if (gsm->ftype == UIH)
2240 pr_debug("Ftype %d i %d\n", gsm->ftype, c->i);
2246 static int gsm_config(struct gsm_mux *gsm, struct gsm_config *c)
2249 int need_restart = 0;
2251 /* Stuff we don't support yet - UI or I frame transport, windowing */
2252 if ((c->adaption != 1 && c->adaption != 2) || c->k)
2254 /* Check the MRU/MTU range looks sane */
2255 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8)
2259 if (c->encapsulation > 1) /* Basic, advanced, no I */
2261 if (c->initiator > 1)
2263 if (c->i == 0 || c->i > 2) /* UIH and UI only */
2266 * See what is needed for reconfiguration
2270 if (c->t1 != 0 && c->t1 != gsm->t1)
2272 if (c->t2 != 0 && c->t2 != gsm->t2)
2274 if (c->encapsulation != gsm->encoding)
2276 if (c->adaption != gsm->adaption)
2279 if (c->initiator != gsm->initiator)
2281 if (c->mru != gsm->mru)
2283 if (c->mtu != gsm->mtu)
2287 * Close down what is needed, restart and initiate the new
2291 if (need_close || need_restart) {
2294 ret = gsm_disconnect(gsm);
2300 gsm_cleanup_mux(gsm);
2302 gsm->initiator = c->initiator;
2305 gsm->encoding = c->encapsulation;
2306 gsm->adaption = c->adaption;
2320 * FIXME: We need to separate activation/deactivation from adding
2321 * and removing from the mux array
2324 gsm_activate_mux(gsm);
2325 if (gsm->initiator && need_close)
2326 gsm_dlci_begin_open(gsm->dlci[0]);
2331 * gsmld_output - write to link
2333 * @data: bytes to output
2336 * Write a block of data from the GSM mux to the data channel. This
2337 * will eventually be serialized from above but at the moment isn't.
2340 static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
2342 if (tty_write_room(gsm->tty) < len) {
2343 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
2347 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET,
2349 gsm->tty->ops->write(gsm->tty, data, len);
2354 * gsmld_attach_gsm - mode set up
2355 * @tty: our tty structure
2358 * Set up the MUX for basic mode and commence connecting to the
2359 * modem. Currently called from the line discipline set up but
2360 * will need moving to an ioctl path.
2363 static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2368 gsm->tty = tty_kref_get(tty);
2369 gsm->output = gsmld_output;
2370 ret = gsm_activate_mux(gsm);
2372 tty_kref_put(gsm->tty);
2374 /* Don't register device 0 - this is the control channel and not
2375 a usable tty interface */
2376 base = mux_num_to_base(gsm); /* Base for this MUX */
2377 for (i = 1; i < NUM_DLCI; i++)
2378 tty_register_device(gsm_tty_driver, base + i, NULL);
2385 * gsmld_detach_gsm - stop doing 0710 mux
2386 * @tty: tty attached to the mux
2389 * Shutdown and then clean up the resources used by the line discipline
2392 static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2394 unsigned int base = mux_num_to_base(gsm); /* Base for this MUX */
2397 WARN_ON(tty != gsm->tty);
2398 for (i = 1; i < NUM_DLCI; i++)
2399 tty_unregister_device(gsm_tty_driver, base + i);
2400 gsm_cleanup_mux(gsm);
2401 tty_kref_put(gsm->tty);
2405 static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
2406 char *fp, int count)
2408 struct gsm_mux *gsm = tty->disc_data;
2409 const unsigned char *dp;
2412 char flags = TTY_NORMAL;
2415 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET,
2418 for (i = count, dp = cp, f = fp; i; i--, dp++) {
2423 gsm->receive(gsm, *dp);
2429 gsm->error(gsm, *dp, flags);
2432 WARN_ONCE(1, "%s: unknown flag %d\n",
2433 tty_name(tty), flags);
2437 /* FASYNC if needed ? */
2438 /* If clogged call tty_throttle(tty); */
2442 * gsmld_flush_buffer - clean input queue
2443 * @tty: terminal device
2445 * Flush the input buffer. Called when the line discipline is
2446 * being closed, when the tty layer wants the buffer flushed (eg
2450 static void gsmld_flush_buffer(struct tty_struct *tty)
2455 * gsmld_close - close the ldisc for this tty
2458 * Called from the terminal layer when this line discipline is
2459 * being shut down, either because of a close or becsuse of a
2460 * discipline change. The function will not be called while other
2461 * ldisc methods are in progress.
2464 static void gsmld_close(struct tty_struct *tty)
2466 struct gsm_mux *gsm = tty->disc_data;
2468 gsmld_detach_gsm(tty, gsm);
2470 gsmld_flush_buffer(tty);
2471 /* Do other clean up here */
2476 * gsmld_open - open an ldisc
2477 * @tty: terminal to open
2479 * Called when this line discipline is being attached to the
2480 * terminal device. Can sleep. Called serialized so that no
2481 * other events will occur in parallel. No further open will occur
2485 static int gsmld_open(struct tty_struct *tty)
2487 struct gsm_mux *gsm;
2490 if (tty->ops->write == NULL)
2493 /* Attach our ldisc data */
2494 gsm = gsm_alloc_mux();
2498 tty->disc_data = gsm;
2499 tty->receive_room = 65536;
2501 /* Attach the initial passive connection */
2504 ret = gsmld_attach_gsm(tty, gsm);
2506 gsm_cleanup_mux(gsm);
2513 * gsmld_write_wakeup - asynchronous I/O notifier
2516 * Required for the ptys, serial driver etc. since processes
2517 * that attach themselves to the master and rely on ASYNC
2518 * IO must be woken up
2521 static void gsmld_write_wakeup(struct tty_struct *tty)
2523 struct gsm_mux *gsm = tty->disc_data;
2524 unsigned long flags;
2527 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2528 spin_lock_irqsave(&gsm->tx_lock, flags);
2530 if (gsm->tx_bytes < TX_THRESH_LO) {
2531 gsm_dlci_data_sweep(gsm);
2533 spin_unlock_irqrestore(&gsm->tx_lock, flags);
2537 * gsmld_read - read function for tty
2539 * @file: file object
2540 * @buf: userspace buffer pointer
2543 * Perform reads for the line discipline. We are guaranteed that the
2544 * line discipline will not be closed under us but we may get multiple
2545 * parallel readers and must handle this ourselves. We may also get
2546 * a hangup. Always called in user context, may sleep.
2548 * This code must be sure never to sleep through a hangup.
2551 static ssize_t gsmld_read(struct tty_struct *tty, struct file *file,
2552 unsigned char __user *buf, size_t nr)
2558 * gsmld_write - write function for tty
2560 * @file: file object
2561 * @buf: userspace buffer pointer
2564 * Called when the owner of the device wants to send a frame
2565 * itself (or some other control data). The data is transferred
2566 * as-is and must be properly framed and checksummed as appropriate
2567 * by userspace. Frames are either sent whole or not at all as this
2568 * avoids pain user side.
2571 static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
2572 const unsigned char *buf, size_t nr)
2574 int space = tty_write_room(tty);
2576 return tty->ops->write(tty, buf, nr);
2577 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2582 * gsmld_poll - poll method for N_GSM0710
2583 * @tty: terminal device
2584 * @file: file accessing it
2587 * Called when the line discipline is asked to poll() for data or
2588 * for special events. This code is not serialized with respect to
2589 * other events save open/close.
2591 * This code must be sure never to sleep through a hangup.
2592 * Called without the kernel lock held - fine
2595 static __poll_t gsmld_poll(struct tty_struct *tty, struct file *file,
2599 struct gsm_mux *gsm = tty->disc_data;
2601 poll_wait(file, &tty->read_wait, wait);
2602 poll_wait(file, &tty->write_wait, wait);
2603 if (tty_hung_up_p(file))
2605 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
2606 mask |= EPOLLOUT | EPOLLWRNORM;
2612 static int gsmld_ioctl(struct tty_struct *tty, struct file *file,
2613 unsigned int cmd, unsigned long arg)
2615 struct gsm_config c;
2616 struct gsm_mux *gsm = tty->disc_data;
2620 case GSMIOC_GETCONF:
2621 gsm_copy_config_values(gsm, &c);
2622 if (copy_to_user((void *)arg, &c, sizeof(c)))
2625 case GSMIOC_SETCONF:
2626 if (copy_from_user(&c, (void *)arg, sizeof(c)))
2628 return gsm_config(gsm, &c);
2629 case GSMIOC_GETFIRST:
2630 base = mux_num_to_base(gsm);
2631 return put_user(base + 1, (__u32 __user *)arg);
2633 return n_tty_ioctl_helper(tty, file, cmd, arg);
2642 static int gsm_mux_net_open(struct net_device *net)
2644 pr_debug("%s called\n", __func__);
2645 netif_start_queue(net);
2649 static int gsm_mux_net_close(struct net_device *net)
2651 netif_stop_queue(net);
2655 static void dlci_net_free(struct gsm_dlci *dlci)
2661 dlci->adaption = dlci->prev_adaption;
2662 dlci->data = dlci->prev_data;
2663 free_netdev(dlci->net);
2666 static void net_free(struct kref *ref)
2668 struct gsm_mux_net *mux_net;
2669 struct gsm_dlci *dlci;
2671 mux_net = container_of(ref, struct gsm_mux_net, ref);
2672 dlci = mux_net->dlci;
2675 unregister_netdev(dlci->net);
2676 dlci_net_free(dlci);
2680 static inline void muxnet_get(struct gsm_mux_net *mux_net)
2682 kref_get(&mux_net->ref);
2685 static inline void muxnet_put(struct gsm_mux_net *mux_net)
2687 kref_put(&mux_net->ref, net_free);
2690 static netdev_tx_t gsm_mux_net_start_xmit(struct sk_buff *skb,
2691 struct net_device *net)
2693 struct gsm_mux_net *mux_net = netdev_priv(net);
2694 struct gsm_dlci *dlci = mux_net->dlci;
2695 muxnet_get(mux_net);
2697 skb_queue_head(&dlci->skb_list, skb);
2698 net->stats.tx_packets++;
2699 net->stats.tx_bytes += skb->len;
2700 gsm_dlci_data_kick(dlci);
2701 /* And tell the kernel when the last transmit started. */
2702 netif_trans_update(net);
2703 muxnet_put(mux_net);
2704 return NETDEV_TX_OK;
2707 /* called when a packet did not ack after watchdogtimeout */
2708 static void gsm_mux_net_tx_timeout(struct net_device *net)
2710 /* Tell syslog we are hosed. */
2711 dev_dbg(&net->dev, "Tx timed out.\n");
2713 /* Update statistics */
2714 net->stats.tx_errors++;
2717 static void gsm_mux_rx_netchar(struct gsm_dlci *dlci,
2718 const unsigned char *in_buf, int size)
2720 struct net_device *net = dlci->net;
2721 struct sk_buff *skb;
2722 struct gsm_mux_net *mux_net = netdev_priv(net);
2723 muxnet_get(mux_net);
2725 /* Allocate an sk_buff */
2726 skb = dev_alloc_skb(size + NET_IP_ALIGN);
2728 /* We got no receive buffer. */
2729 net->stats.rx_dropped++;
2730 muxnet_put(mux_net);
2733 skb_reserve(skb, NET_IP_ALIGN);
2734 skb_put_data(skb, in_buf, size);
2737 skb->protocol = htons(ETH_P_IP);
2739 /* Ship it off to the kernel */
2742 /* update out statistics */
2743 net->stats.rx_packets++;
2744 net->stats.rx_bytes += size;
2745 muxnet_put(mux_net);
2749 static void gsm_mux_net_init(struct net_device *net)
2751 static const struct net_device_ops gsm_netdev_ops = {
2752 .ndo_open = gsm_mux_net_open,
2753 .ndo_stop = gsm_mux_net_close,
2754 .ndo_start_xmit = gsm_mux_net_start_xmit,
2755 .ndo_tx_timeout = gsm_mux_net_tx_timeout,
2758 net->netdev_ops = &gsm_netdev_ops;
2760 /* fill in the other fields */
2761 net->watchdog_timeo = GSM_NET_TX_TIMEOUT;
2762 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
2763 net->type = ARPHRD_NONE;
2764 net->tx_queue_len = 10;
2768 /* caller holds the dlci mutex */
2769 static void gsm_destroy_network(struct gsm_dlci *dlci)
2771 struct gsm_mux_net *mux_net;
2773 pr_debug("destroy network interface");
2776 mux_net = netdev_priv(dlci->net);
2777 muxnet_put(mux_net);
2781 /* caller holds the dlci mutex */
2782 static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
2786 struct net_device *net;
2787 struct gsm_mux_net *mux_net;
2789 if (!capable(CAP_NET_ADMIN))
2792 /* Already in a non tty mode */
2793 if (dlci->adaption > 2)
2796 if (nc->protocol != htons(ETH_P_IP))
2797 return -EPROTONOSUPPORT;
2799 if (nc->adaption != 3 && nc->adaption != 4)
2800 return -EPROTONOSUPPORT;
2802 pr_debug("create network interface");
2805 if (nc->if_name[0] != '\0')
2806 netname = nc->if_name;
2807 net = alloc_netdev(sizeof(struct gsm_mux_net), netname,
2808 NET_NAME_UNKNOWN, gsm_mux_net_init);
2810 pr_err("alloc_netdev failed");
2813 net->mtu = dlci->gsm->mtu;
2815 net->max_mtu = dlci->gsm->mtu;
2816 mux_net = netdev_priv(net);
2817 mux_net->dlci = dlci;
2818 kref_init(&mux_net->ref);
2819 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */
2821 /* reconfigure dlci for network */
2822 dlci->prev_adaption = dlci->adaption;
2823 dlci->prev_data = dlci->data;
2824 dlci->adaption = nc->adaption;
2825 dlci->data = gsm_mux_rx_netchar;
2828 pr_debug("register netdev");
2829 retval = register_netdev(net);
2831 pr_err("network register fail %d\n", retval);
2832 dlci_net_free(dlci);
2835 return net->ifindex; /* return network index */
2838 /* Line discipline for real tty */
2839 static struct tty_ldisc_ops tty_ldisc_packet = {
2840 .owner = THIS_MODULE,
2841 .magic = TTY_LDISC_MAGIC,
2844 .close = gsmld_close,
2845 .flush_buffer = gsmld_flush_buffer,
2847 .write = gsmld_write,
2848 .ioctl = gsmld_ioctl,
2850 .receive_buf = gsmld_receive_buf,
2851 .write_wakeup = gsmld_write_wakeup
2860 static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk)
2863 struct gsm_control *ctrl;
2869 modembits[0] = len << 1 | EA; /* Data bytes */
2870 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */
2871 modembits[2] = gsm_encode_modem(dlci) << 1 | EA;
2873 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */
2874 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1);
2877 return gsm_control_wait(dlci->gsm, ctrl);
2880 static int gsm_carrier_raised(struct tty_port *port)
2882 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2883 struct gsm_mux *gsm = dlci->gsm;
2885 /* Not yet open so no carrier info */
2886 if (dlci->state != DLCI_OPEN)
2892 * Basic mode with control channel in ADM mode may not respond
2893 * to CMD_MSC at all and modem_rx is empty.
2895 if (gsm->encoding == 0 && gsm->dlci[0]->mode == DLCI_MODE_ADM &&
2899 return dlci->modem_rx & TIOCM_CD;
2902 static void gsm_dtr_rts(struct tty_port *port, int onoff)
2904 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2905 unsigned int modem_tx = dlci->modem_tx;
2907 modem_tx |= TIOCM_DTR | TIOCM_RTS;
2909 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
2910 if (modem_tx != dlci->modem_tx) {
2911 dlci->modem_tx = modem_tx;
2912 gsmtty_modem_update(dlci, 0);
2916 static const struct tty_port_operations gsm_port_ops = {
2917 .carrier_raised = gsm_carrier_raised,
2918 .dtr_rts = gsm_dtr_rts,
2919 .destruct = gsm_dlci_free,
2922 static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty)
2924 struct gsm_mux *gsm;
2925 struct gsm_dlci *dlci;
2926 unsigned int line = tty->index;
2927 unsigned int mux = mux_line_to_num(line);
2935 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
2936 if (gsm_mux[mux] == NULL)
2938 if (line == 0 || line > 61) /* 62/63 reserved */
2943 /* If DLCI 0 is not yet fully open return an error.
2944 This is ok from a locking
2945 perspective as we don't have to worry about this
2947 mutex_lock(&gsm->mutex);
2948 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN) {
2949 mutex_unlock(&gsm->mutex);
2952 dlci = gsm->dlci[line];
2955 dlci = gsm_dlci_alloc(gsm, line);
2958 mutex_unlock(&gsm->mutex);
2961 ret = tty_port_install(&dlci->port, driver, tty);
2965 mutex_unlock(&gsm->mutex);
2970 dlci_get(gsm->dlci[0]);
2972 tty->driver_data = dlci;
2973 mutex_unlock(&gsm->mutex);
2978 static int gsmtty_open(struct tty_struct *tty, struct file *filp)
2980 struct gsm_dlci *dlci = tty->driver_data;
2981 struct tty_port *port = &dlci->port;
2984 tty_port_tty_set(port, tty);
2987 /* We could in theory open and close before we wait - eg if we get
2988 a DM straight back. This is ok as that will have caused a hangup */
2989 tty_port_set_initialized(port, 1);
2990 /* Start sending off SABM messages */
2991 gsm_dlci_begin_open(dlci);
2992 /* And wait for virtual carrier */
2993 return tty_port_block_til_ready(port, tty, filp);
2996 static void gsmtty_close(struct tty_struct *tty, struct file *filp)
2998 struct gsm_dlci *dlci = tty->driver_data;
3002 if (dlci->state == DLCI_CLOSED)
3004 mutex_lock(&dlci->mutex);
3005 gsm_destroy_network(dlci);
3006 mutex_unlock(&dlci->mutex);
3007 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
3009 gsm_dlci_begin_close(dlci);
3010 if (tty_port_initialized(&dlci->port) && C_HUPCL(tty))
3011 tty_port_lower_dtr_rts(&dlci->port);
3012 tty_port_close_end(&dlci->port, tty);
3013 tty_port_tty_set(&dlci->port, NULL);
3017 static void gsmtty_hangup(struct tty_struct *tty)
3019 struct gsm_dlci *dlci = tty->driver_data;
3020 if (dlci->state == DLCI_CLOSED)
3022 tty_port_hangup(&dlci->port);
3023 gsm_dlci_begin_close(dlci);
3026 static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf,
3030 struct gsm_dlci *dlci = tty->driver_data;
3031 if (dlci->state == DLCI_CLOSED)
3033 /* Stuff the bytes into the fifo queue */
3034 sent = kfifo_in_locked(dlci->fifo, buf, len, &dlci->lock);
3035 /* Need to kick the channel */
3036 gsm_dlci_data_kick(dlci);
3040 static int gsmtty_write_room(struct tty_struct *tty)
3042 struct gsm_dlci *dlci = tty->driver_data;
3043 if (dlci->state == DLCI_CLOSED)
3045 return TX_SIZE - kfifo_len(dlci->fifo);
3048 static int gsmtty_chars_in_buffer(struct tty_struct *tty)
3050 struct gsm_dlci *dlci = tty->driver_data;
3051 if (dlci->state == DLCI_CLOSED)
3053 return kfifo_len(dlci->fifo);
3056 static void gsmtty_flush_buffer(struct tty_struct *tty)
3058 struct gsm_dlci *dlci = tty->driver_data;
3059 if (dlci->state == DLCI_CLOSED)
3061 /* Caution needed: If we implement reliable transport classes
3062 then the data being transmitted can't simply be junked once
3063 it has first hit the stack. Until then we can just blow it
3065 kfifo_reset(dlci->fifo);
3066 /* Need to unhook this DLCI from the transmit queue logic */
3069 static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
3071 /* The FIFO handles the queue so the kernel will do the right
3072 thing waiting on chars_in_buffer before calling us. No work
3076 static int gsmtty_tiocmget(struct tty_struct *tty)
3078 struct gsm_dlci *dlci = tty->driver_data;
3079 if (dlci->state == DLCI_CLOSED)
3081 return dlci->modem_rx;
3084 static int gsmtty_tiocmset(struct tty_struct *tty,
3085 unsigned int set, unsigned int clear)
3087 struct gsm_dlci *dlci = tty->driver_data;
3088 unsigned int modem_tx = dlci->modem_tx;
3090 if (dlci->state == DLCI_CLOSED)
3095 if (modem_tx != dlci->modem_tx) {
3096 dlci->modem_tx = modem_tx;
3097 return gsmtty_modem_update(dlci, 0);
3103 static int gsmtty_ioctl(struct tty_struct *tty,
3104 unsigned int cmd, unsigned long arg)
3106 struct gsm_dlci *dlci = tty->driver_data;
3107 struct gsm_netconfig nc;
3110 if (dlci->state == DLCI_CLOSED)
3113 case GSMIOC_ENABLE_NET:
3114 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc)))
3116 nc.if_name[IFNAMSIZ-1] = '\0';
3117 /* return net interface index or error code */
3118 mutex_lock(&dlci->mutex);
3119 index = gsm_create_network(dlci, &nc);
3120 mutex_unlock(&dlci->mutex);
3121 if (copy_to_user((void __user *)arg, &nc, sizeof(nc)))
3124 case GSMIOC_DISABLE_NET:
3125 if (!capable(CAP_NET_ADMIN))
3127 mutex_lock(&dlci->mutex);
3128 gsm_destroy_network(dlci);
3129 mutex_unlock(&dlci->mutex);
3132 return -ENOIOCTLCMD;
3136 static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old)
3138 struct gsm_dlci *dlci = tty->driver_data;
3139 if (dlci->state == DLCI_CLOSED)
3141 /* For the moment its fixed. In actual fact the speed information
3142 for the virtual channel can be propogated in both directions by
3143 the RPN control message. This however rapidly gets nasty as we
3144 then have to remap modem signals each way according to whether
3145 our virtual cable is null modem etc .. */
3146 tty_termios_copy_hw(&tty->termios, old);
3149 static void gsmtty_throttle(struct tty_struct *tty)
3151 struct gsm_dlci *dlci = tty->driver_data;
3152 if (dlci->state == DLCI_CLOSED)
3155 dlci->modem_tx &= ~TIOCM_DTR;
3156 dlci->throttled = 1;
3157 /* Send an MSC with DTR cleared */
3158 gsmtty_modem_update(dlci, 0);
3161 static void gsmtty_unthrottle(struct tty_struct *tty)
3163 struct gsm_dlci *dlci = tty->driver_data;
3164 if (dlci->state == DLCI_CLOSED)
3167 dlci->modem_tx |= TIOCM_DTR;
3168 dlci->throttled = 0;
3169 /* Send an MSC with DTR set */
3170 gsmtty_modem_update(dlci, 0);
3173 static int gsmtty_break_ctl(struct tty_struct *tty, int state)
3175 struct gsm_dlci *dlci = tty->driver_data;
3176 int encode = 0; /* Off */
3177 if (dlci->state == DLCI_CLOSED)
3180 if (state == -1) /* "On indefinitely" - we can't encode this
3183 else if (state > 0) {
3184 encode = state / 200; /* mS to encoding */
3186 encode = 0x0F; /* Best effort */
3188 return gsmtty_modem_update(dlci, encode);
3191 static void gsmtty_cleanup(struct tty_struct *tty)
3193 struct gsm_dlci *dlci = tty->driver_data;
3194 struct gsm_mux *gsm = dlci->gsm;
3197 dlci_put(gsm->dlci[0]);
3201 /* Virtual ttys for the demux */
3202 static const struct tty_operations gsmtty_ops = {
3203 .install = gsmtty_install,
3204 .open = gsmtty_open,
3205 .close = gsmtty_close,
3206 .write = gsmtty_write,
3207 .write_room = gsmtty_write_room,
3208 .chars_in_buffer = gsmtty_chars_in_buffer,
3209 .flush_buffer = gsmtty_flush_buffer,
3210 .ioctl = gsmtty_ioctl,
3211 .throttle = gsmtty_throttle,
3212 .unthrottle = gsmtty_unthrottle,
3213 .set_termios = gsmtty_set_termios,
3214 .hangup = gsmtty_hangup,
3215 .wait_until_sent = gsmtty_wait_until_sent,
3216 .tiocmget = gsmtty_tiocmget,
3217 .tiocmset = gsmtty_tiocmset,
3218 .break_ctl = gsmtty_break_ctl,
3219 .cleanup = gsmtty_cleanup,
3224 static int __init gsm_init(void)
3226 /* Fill in our line protocol discipline, and register it */
3227 int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet);
3229 pr_err("n_gsm: can't register line discipline (err = %d)\n",
3234 gsm_tty_driver = alloc_tty_driver(256);
3235 if (!gsm_tty_driver) {
3236 tty_unregister_ldisc(N_GSM0710);
3237 pr_err("gsm_init: tty allocation failed.\n");
3240 gsm_tty_driver->driver_name = "gsmtty";
3241 gsm_tty_driver->name = "gsmtty";
3242 gsm_tty_driver->major = 0; /* Dynamic */
3243 gsm_tty_driver->minor_start = 0;
3244 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
3245 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
3246 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV
3247 | TTY_DRIVER_HARDWARE_BREAK;
3248 gsm_tty_driver->init_termios = tty_std_termios;
3250 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
3251 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
3253 spin_lock_init(&gsm_mux_lock);
3255 if (tty_register_driver(gsm_tty_driver)) {
3256 put_tty_driver(gsm_tty_driver);
3257 tty_unregister_ldisc(N_GSM0710);
3258 pr_err("gsm_init: tty registration failed.\n");
3261 pr_debug("gsm_init: loaded as %d,%d.\n",
3262 gsm_tty_driver->major, gsm_tty_driver->minor_start);
3266 static void __exit gsm_exit(void)
3268 int status = tty_unregister_ldisc(N_GSM0710);
3270 pr_err("n_gsm: can't unregister line discipline (err = %d)\n",
3272 tty_unregister_driver(gsm_tty_driver);
3273 put_tty_driver(gsm_tty_driver);
3276 module_init(gsm_init);
3277 module_exit(gsm_exit);
3280 MODULE_LICENSE("GPL");
3281 MODULE_ALIAS_LDISC(N_GSM0710);