2 * n_gsm.c GSM 0710 tty multiplexor
3 * Copyright (c) 2009/10 Intel Corporation
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
18 * * THIS IS A DEVELOPMENT SNAPSHOT IT IS NOT A FINAL RELEASE *
21 * Mostly done: ioctls for setting modes/timing
22 * Partly done: hooks so you can pull off frames to non tty devs
23 * Restart DLCI 0 when it closes ?
24 * Improve the tx engine
25 * Resolve tx side locking by adding a queue_head and routing
26 * all control traffic via it
27 * General tidy/document
28 * Review the locking/move to refcounts more (mux now moved to an
29 * alloc/free model ready)
30 * Use newest tty open/close port helpers and install hooks
31 * What to do about power functions ?
32 * Termios setting and negotiation
33 * Do we need a 'which mux are you' ioctl to correlate mux and tty sets
37 #include <linux/types.h>
38 #include <linux/major.h>
39 #include <linux/errno.h>
40 #include <linux/signal.h>
41 #include <linux/fcntl.h>
42 #include <linux/sched.h>
43 #include <linux/interrupt.h>
44 #include <linux/tty.h>
45 #include <linux/ctype.h>
47 #include <linux/string.h>
48 #include <linux/slab.h>
49 #include <linux/poll.h>
50 #include <linux/bitops.h>
51 #include <linux/file.h>
52 #include <linux/uaccess.h>
53 #include <linux/module.h>
54 #include <linux/timer.h>
55 #include <linux/tty_flip.h>
56 #include <linux/tty_driver.h>
57 #include <linux/serial.h>
58 #include <linux/kfifo.h>
59 #include <linux/skbuff.h>
62 #include <linux/netdevice.h>
63 #include <linux/etherdevice.h>
64 #include <linux/gsmmux.h>
67 module_param(debug, int, 0600);
69 /* Defaults: these are from the specification */
71 #define T1 10 /* 100mS */
72 #define T2 34 /* 333mS */
73 #define N2 3 /* Retry 3 times */
75 /* Use long timers for testing at low speed with debug on */
82 * Semi-arbitrary buffer size limits. 0710 is normally run with 32-64 byte
83 * limits so this is plenty
87 /* SOF, ADDR, CTRL, LEN1, LEN2, ..., FCS, EOF */
88 #define PROT_OVERHEAD 7
89 #define GSM_NET_TX_TIMEOUT (HZ*10)
92 * struct gsm_mux_net - network interface
93 * @struct gsm_dlci* dlci
94 * @struct net_device_stats stats;
96 * Created when net interface is initialized.
100 struct gsm_dlci *dlci;
101 struct net_device_stats stats;
104 #define STATS(net) (((struct gsm_mux_net *)netdev_priv(net))->stats)
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[0];
122 * Each active data link has a gsm_dlci structure associated which ties
123 * the link layer to an optional tty (if the tty side is open). To avoid
124 * complexity right now these are only ever freed up when the mux is
127 * At the moment we don't free DLCI objects until the mux is torn down
128 * this avoid object life time issues but might be worth review later.
135 #define DLCI_CLOSED 0
136 #define DLCI_OPENING 1 /* Sending SABM not seen UA */
137 #define DLCI_OPEN 2 /* SABM/UA complete */
138 #define DLCI_CLOSING 3 /* Sending DISC not seen UA/DM */
143 #define DLCI_MODE_ABM 0 /* Normal Asynchronous Balanced Mode */
144 #define DLCI_MODE_ADM 1 /* Asynchronous Disconnected Mode */
145 spinlock_t lock; /* Protects the internal state */
146 struct timer_list t1; /* Retransmit timer for SABM and UA */
148 /* Uplink tty if active */
149 struct tty_port port; /* The tty bound to this DLCI if there is one */
150 struct kfifo *fifo; /* Queue fifo for the DLCI */
151 struct kfifo _fifo; /* For new fifo API porting only */
152 int adaption; /* Adaption layer in use */
154 u32 modem_rx; /* Our incoming virtual modem lines */
155 u32 modem_tx; /* Our outgoing modem lines */
156 int dead; /* Refuse re-open */
158 int throttled; /* Private copy of throttle state */
159 int constipated; /* Throttle status for outgoing */
161 struct sk_buff *skb; /* Frame being sent */
162 struct sk_buff_head skb_list; /* Queued frames */
163 /* Data handling callback */
164 void (*data)(struct gsm_dlci *dlci, u8 *data, int len);
165 void (*prev_data)(struct gsm_dlci *dlci, u8 *data, int len);
166 struct net_device *net; /* network interface, if created */
169 /* DLCI 0, 62/63 are special or reserved see gsmtty_open */
174 * DLCI 0 is used to pass control blocks out of band of the data
175 * flow (and with a higher link priority). One command can be outstanding
176 * at a time and we use this structure to manage them. They are created
177 * and destroyed by the user context, and updated by the receive paths
182 u8 cmd; /* Command we are issuing */
183 u8 *data; /* Data for the command in case we retransmit */
184 int len; /* Length of block for retransmission */
185 int done; /* Done flag */
186 int error; /* Error if any */
190 * Each GSM mux we have is represented by this structure. If we are
191 * operating as an ldisc then we use this structure as our ldisc
192 * state. We need to sort out lifetimes and locking with respect
193 * to the gsm mux array. For now we don't free DLCI objects that
194 * have been instantiated until the mux itself is terminated.
196 * To consider further: tty open versus mux shutdown.
200 struct tty_struct *tty; /* The tty our ldisc is bound to */
206 /* Events on the GSM channel */
207 wait_queue_head_t event;
209 /* Bits for GSM mode decoding */
216 #define GSM_ADDRESS 2
217 #define GSM_CONTROL 3
221 #define GSM_OVERRUN 7
226 unsigned int address;
233 u8 *txframe; /* TX framing buffer */
235 /* Methods for the receiver side */
236 void (*receive)(struct gsm_mux *gsm, u8 ch);
237 void (*error)(struct gsm_mux *gsm, u8 ch, u8 flag);
238 /* And transmit side */
239 int (*output)(struct gsm_mux *mux, u8 *data, int len);
244 int initiator; /* Did we initiate connection */
245 int dead; /* Has the mux been shut down */
246 struct gsm_dlci *dlci[NUM_DLCI];
247 int constipated; /* Asked by remote to shut up */
250 unsigned int tx_bytes; /* TX data outstanding */
251 #define TX_THRESH_HI 8192
252 #define TX_THRESH_LO 2048
253 struct list_head tx_list; /* Pending data packets */
255 /* Control messages */
256 struct timer_list t2_timer; /* Retransmit timer for commands */
257 int cretries; /* Command retry counter */
258 struct gsm_control *pending_cmd;/* Our current pending command */
259 spinlock_t control_lock; /* Protects the pending command */
262 int adaption; /* 1 or 2 supported */
263 u8 ftype; /* UI or UIH */
264 int t1, t2; /* Timers in 1/100th of a sec */
265 int n2; /* Retry count */
267 /* Statistics (not currently exposed) */
268 unsigned long bad_fcs;
269 unsigned long malformed;
270 unsigned long io_error;
271 unsigned long bad_size;
272 unsigned long unsupported;
277 * Mux objects - needed so that we can translate a tty index into the
278 * relevant mux and DLCI.
281 #define MAX_MUX 4 /* 256 minors */
282 static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */
283 static spinlock_t gsm_mux_lock;
285 static struct tty_driver *gsm_tty_driver;
288 * This section of the driver logic implements the GSM encodings
289 * both the basic and the 'advanced'. Reliable transport is not
297 /* I is special: the rest are ..*/
308 /* Channel commands */
310 #define CMD_TEST 0x11
313 #define CMD_FCOFF 0x31
316 #define CMD_FCON 0x51
321 /* Virtual modem bits */
328 #define GSM0_SOF 0xF9
329 #define GSM1_SOF 0x7E
330 #define GSM1_ESCAPE 0x7D
331 #define GSM1_ESCAPE_BITS 0x20
334 #define ISO_IEC_646_MASK 0x7F
336 static const struct tty_port_operations gsm_port_ops;
339 * CRC table for GSM 0710
342 static const u8 gsm_fcs8[256] = {
343 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75,
344 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B,
345 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69,
346 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67,
347 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D,
348 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43,
349 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51,
350 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F,
351 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05,
352 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B,
353 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19,
354 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17,
355 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D,
356 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33,
357 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21,
358 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F,
359 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95,
360 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B,
361 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89,
362 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87,
363 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD,
364 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3,
365 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1,
366 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF,
367 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5,
368 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB,
369 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9,
370 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7,
371 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD,
372 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3,
373 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1,
374 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF
377 #define INIT_FCS 0xFF
378 #define GOOD_FCS 0xCF
381 * gsm_fcs_add - update FCS
385 * Update the FCS to include c. Uses the algorithm in the specification
389 static inline u8 gsm_fcs_add(u8 fcs, u8 c)
391 return gsm_fcs8[fcs ^ c];
395 * gsm_fcs_add_block - update FCS for a block
398 * @len: length of buffer
400 * Update the FCS to include c. Uses the algorithm in the specification
404 static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len)
407 fcs = gsm_fcs8[fcs ^ *c++];
412 * gsm_read_ea - read a byte into an EA
413 * @val: variable holding value
414 * c: byte going into the EA
416 * Processes one byte of an EA. Updates the passed variable
417 * and returns 1 if the EA is now completely read
420 static int gsm_read_ea(unsigned int *val, u8 c)
422 /* Add the next 7 bits into the value */
425 /* Was this the last byte of the EA 1 = yes*/
430 * gsm_encode_modem - encode modem data bits
431 * @dlci: DLCI to encode from
433 * Returns the correct GSM encoded modem status bits (6 bit field) for
434 * the current status of the DLCI and attached tty object
437 static u8 gsm_encode_modem(const struct gsm_dlci *dlci)
440 /* FC is true flow control not modem bits */
443 if (dlci->modem_tx & TIOCM_DTR)
444 modembits |= MDM_RTC;
445 if (dlci->modem_tx & TIOCM_RTS)
446 modembits |= MDM_RTR;
447 if (dlci->modem_tx & TIOCM_RI)
449 if (dlci->modem_tx & TIOCM_CD || dlci->gsm->initiator)
455 * gsm_print_packet - display a frame for debug
456 * @hdr: header to print before decode
457 * @addr: address EA from the frame
458 * @cr: C/R bit from the frame
459 * @control: control including PF bit
460 * @data: following data bytes
461 * @dlen: length of data
463 * Displays a packet in human readable format for debugging purposes. The
464 * style is based on amateur radio LAP-B dump display.
467 static void gsm_print_packet(const char *hdr, int addr, int cr,
468 u8 control, const u8 *data, int dlen)
473 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]);
475 switch (control & ~PF) {
495 if (!(control & 0x01)) {
496 pr_cont("I N(S)%d N(R)%d",
497 (control & 0x0E) >> 1, (control & 0xE0) >> 5);
498 } else switch (control & 0x0F) {
500 pr_cont("RR(%d)", (control & 0xE0) >> 5);
503 pr_cont("RNR(%d)", (control & 0xE0) >> 5);
506 pr_cont("REJ(%d)", (control & 0xE0) >> 5);
509 pr_cont("[%02X]", control);
525 pr_cont("%02X ", *data++);
534 * Link level transmission side
538 * gsm_stuff_packet - bytestuff a packet
541 * @len: length of input
543 * Expand a buffer by bytestuffing it. The worst case size change
544 * is doubling and the caller is responsible for handing out
545 * suitable sized buffers.
548 static int gsm_stuff_frame(const u8 *input, u8 *output, int len)
552 if (*input == GSM1_SOF || *input == GSM1_ESCAPE
553 || (*input & ISO_IEC_646_MASK) == XON
554 || (*input & ISO_IEC_646_MASK) == XOFF) {
555 *output++ = GSM1_ESCAPE;
556 *output++ = *input++ ^ GSM1_ESCAPE_BITS;
559 *output++ = *input++;
566 * gsm_send - send a control frame
568 * @addr: address for control frame
569 * @cr: command/response bit
570 * @control: control byte including PF bit
572 * Format up and transmit a control frame. These do not go via the
573 * queueing logic as they should be transmitted ahead of data when
576 * FIXME: Lock versus data TX path
579 static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control)
585 switch (gsm->encoding) {
588 cbuf[1] = (addr << 2) | (cr << 1) | EA;
590 cbuf[3] = EA; /* Length of data = 0 */
591 cbuf[4] = 0xFF - gsm_fcs_add_block(INIT_FCS, cbuf + 1, 3);
597 /* Control frame + packing (but not frame stuffing) in mode 1 */
598 ibuf[0] = (addr << 2) | (cr << 1) | EA;
600 ibuf[2] = 0xFF - gsm_fcs_add_block(INIT_FCS, ibuf, 2);
601 /* Stuffing may double the size worst case */
602 len = gsm_stuff_frame(ibuf, cbuf + 1, 3);
603 /* Now add the SOF markers */
605 cbuf[len + 1] = GSM1_SOF;
606 /* FIXME: we can omit the lead one in many cases */
613 gsm->output(gsm, cbuf, len);
614 gsm_print_packet("-->", addr, cr, control, NULL, 0);
618 * gsm_response - send a control response
620 * @addr: address for control frame
621 * @control: control byte including PF bit
623 * Format up and transmit a link level response frame.
626 static inline void gsm_response(struct gsm_mux *gsm, int addr, int control)
628 gsm_send(gsm, addr, 0, control);
632 * gsm_command - send a control command
634 * @addr: address for control frame
635 * @control: control byte including PF bit
637 * Format up and transmit a link level command frame.
640 static inline void gsm_command(struct gsm_mux *gsm, int addr, int control)
642 gsm_send(gsm, addr, 1, control);
645 /* Data transmission */
647 #define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */
650 * gsm_data_alloc - allocate data frame
652 * @addr: DLCI address
653 * @len: length excluding header and FCS
654 * @ctrl: control byte
656 * Allocate a new data buffer for sending frames with data. Space is left
657 * at the front for header bytes but that is treated as an implementation
658 * detail and not for the high level code to use
661 static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
664 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN,
668 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */
672 INIT_LIST_HEAD(&m->list);
677 * gsm_data_kick - poke the queue
680 * The tty device has called us to indicate that room has appeared in
681 * the transmit queue. Ram more data into the pipe if we have any
682 * If we have been flow-stopped by a CMD_FCOFF, then we can only
683 * send messages on DLCI0 until CMD_FCON
685 * FIXME: lock against link layer control transmissions
688 static void gsm_data_kick(struct gsm_mux *gsm, struct gsm_dlci *dlci)
690 struct gsm_msg *msg, *nmsg;
693 list_for_each_entry_safe(msg, nmsg, &gsm->tx_list, list) {
694 if (gsm->constipated && msg->addr)
696 if (gsm->encoding != 0) {
697 gsm->txframe[0] = GSM1_SOF;
698 len = gsm_stuff_frame(msg->data,
699 gsm->txframe + 1, msg->len);
700 gsm->txframe[len + 1] = GSM1_SOF;
703 gsm->txframe[0] = GSM0_SOF;
704 memcpy(gsm->txframe + 1 , msg->data, msg->len);
705 gsm->txframe[msg->len + 1] = GSM0_SOF;
710 print_hex_dump_bytes("gsm_data_kick: ",
713 if (gsm->output(gsm, gsm->txframe, len) < 0)
715 /* FIXME: Can eliminate one SOF in many more cases */
716 gsm->tx_bytes -= msg->len;
718 list_del(&msg->list);
722 tty_port_tty_wakeup(&dlci->port);
726 for (i = 0; i < NUM_DLCI; i++)
728 tty_port_tty_wakeup(&gsm->dlci[i]->port);
734 * __gsm_data_queue - queue a UI or UIH frame
735 * @dlci: DLCI sending the data
736 * @msg: message queued
738 * Add data to the transmit queue and try and get stuff moving
739 * out of the mux tty if not already doing so. The Caller must hold
743 static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
745 struct gsm_mux *gsm = dlci->gsm;
747 u8 *fcs = dp + msg->len;
749 /* Fill in the header */
750 if (gsm->encoding == 0) {
752 *--dp = (msg->len << 1) | EA;
754 *--dp = (msg->len >> 7); /* bits 7 - 15 */
755 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */
761 *--dp = (msg->addr << 2) | 2 | EA;
763 *--dp = (msg->addr << 2) | EA;
764 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp);
765 /* Ugly protocol layering violation */
766 if (msg->ctrl == UI || msg->ctrl == (UI|PF))
767 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len);
770 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl,
771 msg->data, msg->len);
773 /* Move the header back and adjust the length, also allow for the FCS
774 now tacked on the end */
775 msg->len += (msg->data - dp) + 1;
778 /* Add to the actual output queue */
779 list_add_tail(&msg->list, &gsm->tx_list);
780 gsm->tx_bytes += msg->len;
781 gsm_data_kick(gsm, dlci);
785 * gsm_data_queue - queue a UI or UIH frame
786 * @dlci: DLCI sending the data
787 * @msg: message queued
789 * Add data to the transmit queue and try and get stuff moving
790 * out of the mux tty if not already doing so. Take the
791 * the gsm tx lock and dlci lock.
794 static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
797 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
798 __gsm_data_queue(dlci, msg);
799 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
803 * gsm_dlci_data_output - try and push data out of a DLCI
805 * @dlci: the DLCI to pull data from
807 * Pull data from a DLCI and send it into the transmit queue if there
808 * is data. Keep to the MRU of the mux. This path handles the usual tty
809 * interface which is a byte stream with optional modem data.
811 * Caller must hold the tx_lock of the mux.
814 static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci)
818 int len, total_size, size;
819 int h = dlci->adaption - 1;
823 len = kfifo_len(dlci->fifo);
827 /* MTU/MRU count only the data bits */
833 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
834 /* FIXME: need a timer or something to kick this so it can't
835 get stuck with no work outstanding and no buffer free */
839 switch (dlci->adaption) {
840 case 1: /* Unstructured */
842 case 2: /* Unstructed with modem bits.
843 Always one byte as we never send inline break data */
844 *dp++ = (gsm_encode_modem(dlci) << 1) | EA;
847 WARN_ON(kfifo_out_locked(dlci->fifo, dp , len, &dlci->lock) != len);
848 __gsm_data_queue(dlci, msg);
851 /* Bytes of data we used up */
856 * gsm_dlci_data_output_framed - try and push data out of a DLCI
858 * @dlci: the DLCI to pull data from
860 * Pull data from a DLCI and send it into the transmit queue if there
861 * is data. Keep to the MRU of the mux. This path handles framed data
862 * queued as skbuffs to the DLCI.
864 * Caller must hold the tx_lock of the mux.
867 static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
868 struct gsm_dlci *dlci)
873 int last = 0, first = 0;
876 /* One byte per frame is used for B/F flags */
877 if (dlci->adaption == 4)
880 /* dlci->skb is locked by tx_lock */
881 if (dlci->skb == NULL) {
882 dlci->skb = skb_dequeue_tail(&dlci->skb_list);
883 if (dlci->skb == NULL)
887 len = dlci->skb->len + overhead;
889 /* MTU/MRU count only the data bits */
890 if (len > gsm->mtu) {
891 if (dlci->adaption == 3) {
892 /* Over long frame, bin it */
893 dev_kfree_skb_any(dlci->skb);
901 size = len + overhead;
902 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
904 /* FIXME: need a timer or something to kick this so it can't
905 get stuck with no work outstanding and no buffer free */
907 skb_queue_tail(&dlci->skb_list, dlci->skb);
913 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */
914 /* Flag byte to carry the start/end info */
915 *dp++ = last << 7 | first << 6 | 1; /* EA */
918 memcpy(dp, dlci->skb->data, len);
919 skb_pull(dlci->skb, len);
920 __gsm_data_queue(dlci, msg);
922 dev_kfree_skb_any(dlci->skb);
929 * gsm_dlci_data_sweep - look for data to send
932 * Sweep the GSM mux channels in priority order looking for ones with
933 * data to send. We could do with optimising this scan a bit. We aim
934 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit
935 * TX_THRESH_LO we get called again
937 * FIXME: We should round robin between groups and in theory you can
938 * renegotiate DLCI priorities with optional stuff. Needs optimising.
941 static void gsm_dlci_data_sweep(struct gsm_mux *gsm)
944 /* Priority ordering: We should do priority with RR of the groups */
947 while (i < NUM_DLCI) {
948 struct gsm_dlci *dlci;
950 if (gsm->tx_bytes > TX_THRESH_HI)
953 if (dlci == NULL || dlci->constipated) {
957 if (dlci->adaption < 3 && !dlci->net)
958 len = gsm_dlci_data_output(gsm, dlci);
960 len = gsm_dlci_data_output_framed(gsm, dlci);
963 /* DLCI empty - try the next */
970 * gsm_dlci_data_kick - transmit if possible
971 * @dlci: DLCI to kick
973 * Transmit data from this DLCI if the queue is empty. We can't rely on
974 * a tty wakeup except when we filled the pipe so we need to fire off
975 * new data ourselves in other cases.
978 static void gsm_dlci_data_kick(struct gsm_dlci *dlci)
983 if (dlci->constipated)
986 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
987 /* If we have nothing running then we need to fire up */
988 sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO);
989 if (dlci->gsm->tx_bytes == 0) {
991 gsm_dlci_data_output_framed(dlci->gsm, dlci);
993 gsm_dlci_data_output(dlci->gsm, dlci);
996 gsm_dlci_data_sweep(dlci->gsm);
997 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
1001 * Control message processing
1006 * gsm_control_reply - send a response frame to a control
1008 * @cmd: the command to use
1009 * @data: data to follow encoded info
1010 * @dlen: length of data
1012 * Encode up and queue a UI/UIH frame containing our response.
1015 static void gsm_control_reply(struct gsm_mux *gsm, int cmd, u8 *data,
1018 struct gsm_msg *msg;
1019 msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype);
1022 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */
1023 msg->data[1] = (dlen << 1) | EA;
1024 memcpy(msg->data + 2, data, dlen);
1025 gsm_data_queue(gsm->dlci[0], msg);
1029 * gsm_process_modem - process received modem status
1030 * @tty: virtual tty bound to the DLCI
1031 * @dlci: DLCI to affect
1032 * @modem: modem bits (full EA)
1034 * Used when a modem control message or line state inline in adaption
1035 * layer 2 is processed. Sort out the local modem state and throttles
1038 static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
1039 u32 modem, int clen)
1045 /* The modem status command can either contain one octet (v.24 signals)
1046 or two octets (v.24 signals + break signals). The length field will
1047 either be 2 or 3 respectively. This is specified in section
1048 5.4.6.3.7 of the 27.010 mux spec. */
1051 modem = modem & 0x7f;
1054 modem = (modem >> 7) & 0x7f;
1057 /* Flow control/ready to communicate */
1058 fc = (modem & MDM_FC) || !(modem & MDM_RTR);
1059 if (fc && !dlci->constipated) {
1060 /* Need to throttle our output on this device */
1061 dlci->constipated = 1;
1062 } else if (!fc && dlci->constipated) {
1063 dlci->constipated = 0;
1064 gsm_dlci_data_kick(dlci);
1067 /* Map modem bits */
1068 if (modem & MDM_RTC)
1069 mlines |= TIOCM_DSR | TIOCM_DTR;
1070 if (modem & MDM_RTR)
1071 mlines |= TIOCM_RTS | TIOCM_CTS;
1077 /* Carrier drop -> hangup */
1079 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD))
1084 tty_insert_flip_char(&dlci->port, 0, TTY_BREAK);
1085 dlci->modem_rx = mlines;
1089 * gsm_control_modem - modem status received
1091 * @data: data following command
1092 * @clen: command length
1094 * We have received a modem status control message. This is used by
1095 * the GSM mux protocol to pass virtual modem line status and optionally
1096 * to indicate break signals. Unpack it, convert to Linux representation
1097 * and if need be stuff a break message down the tty.
1100 static void gsm_control_modem(struct gsm_mux *gsm, u8 *data, int clen)
1102 unsigned int addr = 0;
1103 unsigned int modem = 0;
1104 unsigned int brk = 0;
1105 struct gsm_dlci *dlci;
1108 struct tty_struct *tty;
1110 while (gsm_read_ea(&addr, *dp++) == 0) {
1115 /* Must be at least one byte following the EA */
1121 /* Closed port, or invalid ? */
1122 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1124 dlci = gsm->dlci[addr];
1126 while (gsm_read_ea(&modem, *dp++) == 0) {
1133 while (gsm_read_ea(&brk, *dp++) == 0) {
1139 modem |= (brk & 0x7f);
1141 tty = tty_port_tty_get(&dlci->port);
1142 gsm_process_modem(tty, dlci, modem, clen);
1147 gsm_control_reply(gsm, CMD_MSC, data, clen);
1151 * gsm_control_rls - remote line status
1154 * @clen: data length
1156 * The modem sends us a two byte message on the control channel whenever
1157 * it wishes to send us an error state from the virtual link. Stuff
1158 * this into the uplink tty if present
1161 static void gsm_control_rls(struct gsm_mux *gsm, u8 *data, int clen)
1163 struct tty_port *port;
1164 unsigned int addr = 0;
1169 while (gsm_read_ea(&addr, *dp++) == 0) {
1174 /* Must be at least one byte following ea */
1179 /* Closed port, or invalid ? */
1180 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1184 if ((bits & 1) == 0)
1187 port = &gsm->dlci[addr]->port;
1190 tty_insert_flip_char(port, 0, TTY_OVERRUN);
1192 tty_insert_flip_char(port, 0, TTY_PARITY);
1194 tty_insert_flip_char(port, 0, TTY_FRAME);
1196 tty_flip_buffer_push(port);
1198 gsm_control_reply(gsm, CMD_RLS, data, clen);
1201 static void gsm_dlci_begin_close(struct gsm_dlci *dlci);
1204 * gsm_control_message - DLCI 0 control processing
1206 * @command: the command EA
1207 * @data: data beyond the command/length EAs
1210 * Input processor for control messages from the other end of the link.
1211 * Processes the incoming request and queues a response frame or an
1212 * NSC response if not supported
1215 static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
1219 unsigned long flags;
1223 struct gsm_dlci *dlci = gsm->dlci[0];
1224 /* Modem wishes to close down */
1228 gsm_dlci_begin_close(dlci);
1233 /* Modem wishes to test, reply with the data */
1234 gsm_control_reply(gsm, CMD_TEST, data, clen);
1237 /* Modem can accept data again */
1238 gsm->constipated = 0;
1239 gsm_control_reply(gsm, CMD_FCON, NULL, 0);
1240 /* Kick the link in case it is idling */
1241 spin_lock_irqsave(&gsm->tx_lock, flags);
1242 gsm_data_kick(gsm, NULL);
1243 spin_unlock_irqrestore(&gsm->tx_lock, flags);
1246 /* Modem wants us to STFU */
1247 gsm->constipated = 1;
1248 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0);
1251 /* Out of band modem line change indicator for a DLCI */
1252 gsm_control_modem(gsm, data, clen);
1255 /* Out of band error reception for a DLCI */
1256 gsm_control_rls(gsm, data, clen);
1259 /* Modem wishes to enter power saving state */
1260 gsm_control_reply(gsm, CMD_PSC, NULL, 0);
1262 /* Optional unsupported commands */
1263 case CMD_PN: /* Parameter negotiation */
1264 case CMD_RPN: /* Remote port negotiation */
1265 case CMD_SNC: /* Service negotiation command */
1267 /* Reply to bad commands with an NSC */
1269 gsm_control_reply(gsm, CMD_NSC, buf, 1);
1275 * gsm_control_response - process a response to our control
1277 * @command: the command (response) EA
1278 * @data: data beyond the command/length EA
1281 * Process a response to an outstanding command. We only allow a single
1282 * control message in flight so this is fairly easy. All the clean up
1283 * is done by the caller, we just update the fields, flag it as done
1287 static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
1290 struct gsm_control *ctrl;
1291 unsigned long flags;
1293 spin_lock_irqsave(&gsm->control_lock, flags);
1295 ctrl = gsm->pending_cmd;
1296 /* Does the reply match our command */
1298 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) {
1299 /* Our command was replied to, kill the retry timer */
1300 del_timer(&gsm->t2_timer);
1301 gsm->pending_cmd = NULL;
1302 /* Rejected by the other end */
1303 if (command == CMD_NSC)
1304 ctrl->error = -EOPNOTSUPP;
1306 wake_up(&gsm->event);
1308 spin_unlock_irqrestore(&gsm->control_lock, flags);
1312 * gsm_control_transmit - send control packet
1314 * @ctrl: frame to send
1316 * Send out a pending control command (called under control lock)
1319 static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl)
1321 struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 2, gsm->ftype);
1324 msg->data[0] = (ctrl->cmd << 1) | CR | EA; /* command */
1325 msg->data[1] = (ctrl->len << 1) | EA;
1326 memcpy(msg->data + 2, ctrl->data, ctrl->len);
1327 gsm_data_queue(gsm->dlci[0], msg);
1331 * gsm_control_retransmit - retransmit a control frame
1332 * @data: pointer to our gsm object
1334 * Called off the T2 timer expiry in order to retransmit control frames
1335 * that have been lost in the system somewhere. The control_lock protects
1336 * us from colliding with another sender or a receive completion event.
1337 * In that situation the timer may still occur in a small window but
1338 * gsm->pending_cmd will be NULL and we just let the timer expire.
1341 static void gsm_control_retransmit(unsigned long data)
1343 struct gsm_mux *gsm = (struct gsm_mux *)data;
1344 struct gsm_control *ctrl;
1345 unsigned long flags;
1346 spin_lock_irqsave(&gsm->control_lock, flags);
1347 ctrl = gsm->pending_cmd;
1349 if (gsm->cretries == 0) {
1350 gsm->pending_cmd = NULL;
1351 ctrl->error = -ETIMEDOUT;
1353 spin_unlock_irqrestore(&gsm->control_lock, flags);
1354 wake_up(&gsm->event);
1358 gsm_control_transmit(gsm, ctrl);
1359 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1361 spin_unlock_irqrestore(&gsm->control_lock, flags);
1365 * gsm_control_send - send a control frame on DLCI 0
1366 * @gsm: the GSM channel
1367 * @command: command to send including CR bit
1368 * @data: bytes of data (must be kmalloced)
1369 * @len: length of the block to send
1371 * Queue and dispatch a control command. Only one command can be
1372 * active at a time. In theory more can be outstanding but the matching
1373 * gets really complicated so for now stick to one outstanding.
1376 static struct gsm_control *gsm_control_send(struct gsm_mux *gsm,
1377 unsigned int command, u8 *data, int clen)
1379 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control),
1381 unsigned long flags;
1385 wait_event(gsm->event, gsm->pending_cmd == NULL);
1386 spin_lock_irqsave(&gsm->control_lock, flags);
1387 if (gsm->pending_cmd != NULL) {
1388 spin_unlock_irqrestore(&gsm->control_lock, flags);
1391 ctrl->cmd = command;
1394 gsm->pending_cmd = ctrl;
1396 /* If DLCI0 is in ADM mode skip retries, it won't respond */
1397 if (gsm->dlci[0]->mode == DLCI_MODE_ADM)
1400 gsm->cretries = gsm->n2;
1402 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1403 gsm_control_transmit(gsm, ctrl);
1404 spin_unlock_irqrestore(&gsm->control_lock, flags);
1409 * gsm_control_wait - wait for a control to finish
1411 * @control: control we are waiting on
1413 * Waits for the control to complete or time out. Frees any used
1414 * resources and returns 0 for success, or an error if the remote
1415 * rejected or ignored the request.
1418 static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
1421 wait_event(gsm->event, control->done == 1);
1422 err = control->error;
1429 * DLCI level handling: Needs krefs
1433 * State transitions and timers
1437 * gsm_dlci_close - a DLCI has closed
1438 * @dlci: DLCI that closed
1440 * Perform processing when moving a DLCI into closed state. If there
1441 * is an attached tty this is hung up
1444 static void gsm_dlci_close(struct gsm_dlci *dlci)
1446 del_timer(&dlci->t1);
1448 pr_debug("DLCI %d goes closed.\n", dlci->addr);
1449 dlci->state = DLCI_CLOSED;
1450 if (dlci->addr != 0) {
1451 tty_port_tty_hangup(&dlci->port, false);
1452 kfifo_reset(dlci->fifo);
1454 dlci->gsm->dead = 1;
1455 wake_up(&dlci->gsm->event);
1456 /* A DLCI 0 close is a MUX termination so we need to kick that
1457 back to userspace somehow */
1461 * gsm_dlci_open - a DLCI has opened
1462 * @dlci: DLCI that opened
1464 * Perform processing when moving a DLCI into open state.
1467 static void gsm_dlci_open(struct gsm_dlci *dlci)
1469 /* Note that SABM UA .. SABM UA first UA lost can mean that we go
1471 del_timer(&dlci->t1);
1472 /* This will let a tty open continue */
1473 dlci->state = DLCI_OPEN;
1475 pr_debug("DLCI %d goes open.\n", dlci->addr);
1476 wake_up(&dlci->gsm->event);
1480 * gsm_dlci_t1 - T1 timer expiry
1481 * @dlci: DLCI that opened
1483 * The T1 timer handles retransmits of control frames (essentially of
1484 * SABM and DISC). We resend the command until the retry count runs out
1485 * in which case an opening port goes back to closed and a closing port
1486 * is simply put into closed state (any further frames from the other
1487 * end will get a DM response)
1489 * Some control dlci can stay in ADM mode with other dlci working just
1490 * fine. In that case we can just keep the control dlci open after the
1491 * DLCI_OPENING retries time out.
1494 static void gsm_dlci_t1(unsigned long data)
1496 struct gsm_dlci *dlci = (struct gsm_dlci *)data;
1497 struct gsm_mux *gsm = dlci->gsm;
1499 switch (dlci->state) {
1502 if (dlci->retries) {
1503 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1504 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1505 } else if (!dlci->addr && gsm->control == (DM | PF)) {
1507 pr_info("DLCI %d opening in ADM mode.\n",
1509 dlci->mode = DLCI_MODE_ADM;
1510 gsm_dlci_open(dlci);
1512 gsm_dlci_begin_close(dlci); /* prevent half open link */
1518 if (dlci->retries) {
1519 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1520 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1522 gsm_dlci_close(dlci);
1528 * gsm_dlci_begin_open - start channel open procedure
1529 * @dlci: DLCI to open
1531 * Commence opening a DLCI from the Linux side. We issue SABM messages
1532 * to the modem which should then reply with a UA or ADM, at which point
1533 * we will move into open state. Opening is done asynchronously with retry
1534 * running off timers and the responses.
1537 static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
1539 struct gsm_mux *gsm = dlci->gsm;
1540 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING)
1542 dlci->retries = gsm->n2;
1543 dlci->state = DLCI_OPENING;
1544 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1545 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1549 * gsm_dlci_begin_close - start channel open procedure
1550 * @dlci: DLCI to open
1552 * Commence closing a DLCI from the Linux side. We issue DISC messages
1553 * to the modem which should then reply with a UA, at which point we
1554 * will move into closed state. Closing is done asynchronously with retry
1555 * off timers. We may also receive a DM reply from the other end which
1556 * indicates the channel was already closed.
1559 static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
1561 struct gsm_mux *gsm = dlci->gsm;
1562 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
1564 dlci->retries = gsm->n2;
1565 dlci->state = DLCI_CLOSING;
1566 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1567 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1571 * gsm_dlci_data - data arrived
1573 * @data: block of bytes received
1574 * @len: length of received block
1576 * A UI or UIH frame has arrived which contains data for a channel
1577 * other than the control channel. If the relevant virtual tty is
1578 * open we shovel the bits down it, if not we drop them.
1581 static void gsm_dlci_data(struct gsm_dlci *dlci, u8 *data, int clen)
1584 struct tty_port *port = &dlci->port;
1585 struct tty_struct *tty;
1586 unsigned int modem = 0;
1590 pr_debug("%d bytes for tty\n", len);
1591 switch (dlci->adaption) {
1592 /* Unsupported types */
1593 /* Packetised interruptible data */
1596 /* Packetised uininterruptible voice/data */
1599 /* Asynchronous serial with line state in each frame */
1601 while (gsm_read_ea(&modem, *data++) == 0) {
1606 tty = tty_port_tty_get(port);
1608 gsm_process_modem(tty, dlci, modem, clen);
1611 /* Line state will go via DLCI 0 controls only */
1614 tty_insert_flip_string(port, data, len);
1615 tty_flip_buffer_push(port);
1620 * gsm_dlci_control - data arrived on control channel
1622 * @data: block of bytes received
1623 * @len: length of received block
1625 * A UI or UIH frame has arrived which contains data for DLCI 0 the
1626 * control channel. This should contain a command EA followed by
1627 * control data bytes. The command EA contains a command/response bit
1628 * and we divide up the work accordingly.
1631 static void gsm_dlci_command(struct gsm_dlci *dlci, u8 *data, int len)
1633 /* See what command is involved */
1634 unsigned int command = 0;
1636 if (gsm_read_ea(&command, *data++) == 1) {
1639 /* FIXME: this is properly an EA */
1641 /* Malformed command ? */
1645 gsm_control_message(dlci->gsm, command,
1648 gsm_control_response(dlci->gsm, command,
1656 * Allocate/Free DLCI channels
1660 * gsm_dlci_alloc - allocate a DLCI
1662 * @addr: address of the DLCI
1664 * Allocate and install a new DLCI object into the GSM mux.
1666 * FIXME: review locking races
1669 static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
1671 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC);
1674 spin_lock_init(&dlci->lock);
1675 mutex_init(&dlci->mutex);
1676 dlci->fifo = &dlci->_fifo;
1677 if (kfifo_alloc(&dlci->_fifo, 4096, GFP_KERNEL) < 0) {
1682 skb_queue_head_init(&dlci->skb_list);
1683 init_timer(&dlci->t1);
1684 dlci->t1.function = gsm_dlci_t1;
1685 dlci->t1.data = (unsigned long)dlci;
1686 tty_port_init(&dlci->port);
1687 dlci->port.ops = &gsm_port_ops;
1690 dlci->adaption = gsm->adaption;
1691 dlci->state = DLCI_CLOSED;
1693 dlci->data = gsm_dlci_data;
1695 dlci->data = gsm_dlci_command;
1696 gsm->dlci[addr] = dlci;
1701 * gsm_dlci_free - free DLCI
1702 * @dlci: DLCI to free
1708 static void gsm_dlci_free(struct tty_port *port)
1710 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
1712 del_timer_sync(&dlci->t1);
1713 dlci->gsm->dlci[dlci->addr] = NULL;
1714 kfifo_free(dlci->fifo);
1715 while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
1716 dev_kfree_skb(dlci->skb);
1720 static inline void dlci_get(struct gsm_dlci *dlci)
1722 tty_port_get(&dlci->port);
1725 static inline void dlci_put(struct gsm_dlci *dlci)
1727 tty_port_put(&dlci->port);
1730 static void gsm_destroy_network(struct gsm_dlci *dlci);
1733 * gsm_dlci_release - release DLCI
1734 * @dlci: DLCI to destroy
1736 * Release a DLCI. Actual free is deferred until either
1737 * mux is closed or tty is closed - whichever is last.
1741 static void gsm_dlci_release(struct gsm_dlci *dlci)
1743 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1745 mutex_lock(&dlci->mutex);
1746 gsm_destroy_network(dlci);
1747 mutex_unlock(&dlci->mutex);
1751 tty_port_tty_set(&dlci->port, NULL);
1754 dlci->state = DLCI_CLOSED;
1759 * LAPBish link layer logic
1763 * gsm_queue - a GSM frame is ready to process
1764 * @gsm: pointer to our gsm mux
1766 * At this point in time a frame has arrived and been demangled from
1767 * the line encoding. All the differences between the encodings have
1768 * been handled below us and the frame is unpacked into the structures.
1769 * The fcs holds the header FCS but any data FCS must be added here.
1772 static void gsm_queue(struct gsm_mux *gsm)
1774 struct gsm_dlci *dlci;
1777 /* We have to sneak a look at the packet body to do the FCS.
1778 A somewhat layering violation in the spec */
1780 if ((gsm->control & ~PF) == UI)
1781 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len);
1782 if (gsm->encoding == 0) {
1783 /* WARNING: gsm->received_fcs is used for
1784 gsm->encoding = 0 only.
1785 In this case it contain the last piece of data
1786 required to generate final CRC */
1787 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs);
1789 if (gsm->fcs != GOOD_FCS) {
1792 pr_debug("BAD FCS %02x\n", gsm->fcs);
1795 address = gsm->address >> 1;
1796 if (address >= NUM_DLCI)
1799 cr = gsm->address & 1; /* C/R bit */
1801 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
1803 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */
1804 dlci = gsm->dlci[address];
1806 switch (gsm->control) {
1811 dlci = gsm_dlci_alloc(gsm, address);
1815 gsm_response(gsm, address, DM);
1817 gsm_response(gsm, address, UA);
1818 gsm_dlci_open(dlci);
1824 if (dlci == NULL || dlci->state == DLCI_CLOSED) {
1825 gsm_response(gsm, address, DM);
1828 /* Real close complete */
1829 gsm_response(gsm, address, UA);
1830 gsm_dlci_close(dlci);
1833 if (cr == 0 || dlci == NULL)
1835 switch (dlci->state) {
1837 gsm_dlci_close(dlci);
1840 gsm_dlci_open(dlci);
1844 case DM: /* DM can be valid unsolicited */
1850 gsm_dlci_close(dlci);
1860 if (dlci == NULL || dlci->state != DLCI_OPEN) {
1861 gsm_command(gsm, address, DM|PF);
1864 dlci->data(dlci, gsm->buf, gsm->len);
1877 * gsm0_receive - perform processing for non-transparency
1878 * @gsm: gsm data for this ldisc instance
1881 * Receive bytes in gsm mode 0
1884 static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
1888 switch (gsm->state) {
1889 case GSM_SEARCH: /* SOF marker */
1890 if (c == GSM0_SOF) {
1891 gsm->state = GSM_ADDRESS;
1894 gsm->fcs = INIT_FCS;
1897 case GSM_ADDRESS: /* Address EA */
1898 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1899 if (gsm_read_ea(&gsm->address, c))
1900 gsm->state = GSM_CONTROL;
1902 case GSM_CONTROL: /* Control Byte */
1903 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1905 gsm->state = GSM_LEN0;
1907 case GSM_LEN0: /* Length EA */
1908 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1909 if (gsm_read_ea(&gsm->len, c)) {
1910 if (gsm->len > gsm->mru) {
1912 gsm->state = GSM_SEARCH;
1917 gsm->state = GSM_FCS;
1919 gsm->state = GSM_DATA;
1922 gsm->state = GSM_LEN1;
1925 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1927 gsm->len |= len << 7;
1928 if (gsm->len > gsm->mru) {
1930 gsm->state = GSM_SEARCH;
1935 gsm->state = GSM_FCS;
1937 gsm->state = GSM_DATA;
1939 case GSM_DATA: /* Data */
1940 gsm->buf[gsm->count++] = c;
1941 if (gsm->count == gsm->len)
1942 gsm->state = GSM_FCS;
1944 case GSM_FCS: /* FCS follows the packet */
1945 gsm->received_fcs = c;
1947 gsm->state = GSM_SSOF;
1950 if (c == GSM0_SOF) {
1951 gsm->state = GSM_SEARCH;
1959 * gsm1_receive - perform processing for non-transparency
1960 * @gsm: gsm data for this ldisc instance
1963 * Receive bytes in mode 1 (Advanced option)
1966 static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
1968 if (c == GSM1_SOF) {
1969 /* EOF is only valid in frame if we have got to the data state
1970 and received at least one byte (the FCS) */
1971 if (gsm->state == GSM_DATA && gsm->count) {
1972 /* Extract the FCS */
1974 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
1975 gsm->len = gsm->count;
1977 gsm->state = GSM_START;
1980 /* Any partial frame was a runt so go back to start */
1981 if (gsm->state != GSM_START) {
1982 if (gsm->state != GSM_SEARCH)
1984 gsm->state = GSM_START;
1986 /* A SOF in GSM_START means we are still reading idling or
1991 if (c == GSM1_ESCAPE) {
1996 /* Only an unescaped SOF gets us out of GSM search */
1997 if (gsm->state == GSM_SEARCH)
2001 c ^= GSM1_ESCAPE_BITS;
2004 switch (gsm->state) {
2005 case GSM_START: /* First byte after SOF */
2007 gsm->state = GSM_ADDRESS;
2008 gsm->fcs = INIT_FCS;
2010 case GSM_ADDRESS: /* Address continuation */
2011 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2012 if (gsm_read_ea(&gsm->address, c))
2013 gsm->state = GSM_CONTROL;
2015 case GSM_CONTROL: /* Control Byte */
2016 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2019 gsm->state = GSM_DATA;
2021 case GSM_DATA: /* Data */
2022 if (gsm->count > gsm->mru) { /* Allow one for the FCS */
2023 gsm->state = GSM_OVERRUN;
2026 gsm->buf[gsm->count++] = c;
2028 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */
2034 * gsm_error - handle tty error
2036 * @data: byte received (may be invalid)
2037 * @flag: error received
2039 * Handle an error in the receipt of data for a frame. Currently we just
2040 * go back to hunting for a SOF.
2042 * FIXME: better diagnostics ?
2045 static void gsm_error(struct gsm_mux *gsm,
2046 unsigned char data, unsigned char flag)
2048 gsm->state = GSM_SEARCH;
2053 * gsm_cleanup_mux - generic GSM protocol cleanup
2056 * Clean up the bits of the mux which are the same for all framing
2057 * protocols. Remove the mux from the mux table, stop all the timers
2058 * and then shut down each device hanging up the channels as we go.
2061 static void gsm_cleanup_mux(struct gsm_mux *gsm)
2064 struct gsm_dlci *dlci = gsm->dlci[0];
2065 struct gsm_msg *txq, *ntxq;
2066 struct gsm_control *gc;
2070 spin_lock(&gsm_mux_lock);
2071 for (i = 0; i < MAX_MUX; i++) {
2072 if (gsm_mux[i] == gsm) {
2077 spin_unlock(&gsm_mux_lock);
2078 /* open failed before registering => nothing to do */
2082 /* In theory disconnecting DLCI 0 is sufficient but for some
2083 modems this is apparently not the case. */
2085 gc = gsm_control_send(gsm, CMD_CLD, NULL, 0);
2087 gsm_control_wait(gsm, gc);
2089 del_timer_sync(&gsm->t2_timer);
2090 /* Now we are sure T2 has stopped */
2093 gsm_dlci_begin_close(dlci);
2094 wait_event_interruptible(gsm->event,
2095 dlci->state == DLCI_CLOSED);
2097 /* Free up any link layer users */
2098 mutex_lock(&gsm->mutex);
2099 for (i = 0; i < NUM_DLCI; i++)
2101 gsm_dlci_release(gsm->dlci[i]);
2102 mutex_unlock(&gsm->mutex);
2103 /* Now wipe the queues */
2104 tty_ldisc_flush(gsm->tty);
2105 list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list)
2107 INIT_LIST_HEAD(&gsm->tx_list);
2111 * gsm_activate_mux - generic GSM setup
2114 * Set up the bits of the mux which are the same for all framing
2115 * protocols. Add the mux to the mux table so it can be opened and
2116 * finally kick off connecting to DLCI 0 on the modem.
2119 static int gsm_activate_mux(struct gsm_mux *gsm)
2121 struct gsm_dlci *dlci;
2124 setup_timer(&gsm->t2_timer, gsm_control_retransmit, (unsigned long)gsm);
2125 init_waitqueue_head(&gsm->event);
2126 spin_lock_init(&gsm->control_lock);
2127 spin_lock_init(&gsm->tx_lock);
2129 if (gsm->encoding == 0)
2130 gsm->receive = gsm0_receive;
2132 gsm->receive = gsm1_receive;
2133 gsm->error = gsm_error;
2135 spin_lock(&gsm_mux_lock);
2136 for (i = 0; i < MAX_MUX; i++) {
2137 if (gsm_mux[i] == NULL) {
2143 spin_unlock(&gsm_mux_lock);
2147 dlci = gsm_dlci_alloc(gsm, 0);
2150 gsm->dead = 0; /* Tty opens are now permissible */
2155 * gsm_free_mux - free up a mux
2158 * Dispose of allocated resources for a dead mux
2160 static void gsm_free_mux(struct gsm_mux *gsm)
2162 kfree(gsm->txframe);
2168 * gsm_free_muxr - free up a mux
2171 * Dispose of allocated resources for a dead mux
2173 static void gsm_free_muxr(struct kref *ref)
2175 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref);
2179 static inline void mux_get(struct gsm_mux *gsm)
2181 kref_get(&gsm->ref);
2184 static inline void mux_put(struct gsm_mux *gsm)
2186 kref_put(&gsm->ref, gsm_free_muxr);
2190 * gsm_alloc_mux - allocate a mux
2192 * Creates a new mux ready for activation.
2195 static struct gsm_mux *gsm_alloc_mux(void)
2197 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
2200 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL);
2201 if (gsm->buf == NULL) {
2205 gsm->txframe = kmalloc(2 * (MAX_MTU + PROT_OVERHEAD - 1), GFP_KERNEL);
2206 if (gsm->txframe == NULL) {
2211 spin_lock_init(&gsm->lock);
2212 mutex_init(&gsm->mutex);
2213 kref_init(&gsm->ref);
2214 INIT_LIST_HEAD(&gsm->tx_list);
2222 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
2224 gsm->dead = 1; /* Avoid early tty opens */
2230 * gsmld_output - write to link
2232 * @data: bytes to output
2235 * Write a block of data from the GSM mux to the data channel. This
2236 * will eventually be serialized from above but at the moment isn't.
2239 static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
2241 if (tty_write_room(gsm->tty) < len) {
2242 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
2246 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET,
2248 gsm->tty->ops->write(gsm->tty, data, len);
2253 * gsmld_attach_gsm - mode set up
2254 * @tty: our tty structure
2257 * Set up the MUX for basic mode and commence connecting to the
2258 * modem. Currently called from the line discipline set up but
2259 * will need moving to an ioctl path.
2262 static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2266 gsm->tty = tty_kref_get(tty);
2267 gsm->output = gsmld_output;
2268 ret = gsm_activate_mux(gsm);
2270 tty_kref_put(gsm->tty);
2272 /* Don't register device 0 - this is the control channel and not
2273 a usable tty interface */
2274 base = gsm->num << 6; /* Base for this MUX */
2275 for (i = 1; i < NUM_DLCI; i++)
2276 tty_register_device(gsm_tty_driver, base + i, NULL);
2283 * gsmld_detach_gsm - stop doing 0710 mux
2284 * @tty: tty attached to the mux
2287 * Shutdown and then clean up the resources used by the line discipline
2290 static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2293 int base = gsm->num << 6; /* Base for this MUX */
2295 WARN_ON(tty != gsm->tty);
2296 for (i = 1; i < NUM_DLCI; i++)
2297 tty_unregister_device(gsm_tty_driver, base + i);
2298 gsm_cleanup_mux(gsm);
2299 tty_kref_put(gsm->tty);
2303 static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
2304 char *fp, int count)
2306 struct gsm_mux *gsm = tty->disc_data;
2307 const unsigned char *dp;
2310 char flags = TTY_NORMAL;
2313 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET,
2316 for (i = count, dp = cp, f = fp; i; i--, dp++) {
2321 gsm->receive(gsm, *dp);
2327 gsm->error(gsm, *dp, flags);
2330 WARN_ONCE(1, "%s: unknown flag %d\n",
2331 tty_name(tty), flags);
2335 /* FASYNC if needed ? */
2336 /* If clogged call tty_throttle(tty); */
2340 * gsmld_flush_buffer - clean input queue
2341 * @tty: terminal device
2343 * Flush the input buffer. Called when the line discipline is
2344 * being closed, when the tty layer wants the buffer flushed (eg
2348 static void gsmld_flush_buffer(struct tty_struct *tty)
2353 * gsmld_close - close the ldisc for this tty
2356 * Called from the terminal layer when this line discipline is
2357 * being shut down, either because of a close or becsuse of a
2358 * discipline change. The function will not be called while other
2359 * ldisc methods are in progress.
2362 static void gsmld_close(struct tty_struct *tty)
2364 struct gsm_mux *gsm = tty->disc_data;
2366 gsmld_detach_gsm(tty, gsm);
2368 gsmld_flush_buffer(tty);
2369 /* Do other clean up here */
2374 * gsmld_open - open an ldisc
2375 * @tty: terminal to open
2377 * Called when this line discipline is being attached to the
2378 * terminal device. Can sleep. Called serialized so that no
2379 * other events will occur in parallel. No further open will occur
2383 static int gsmld_open(struct tty_struct *tty)
2385 struct gsm_mux *gsm;
2388 if (tty->ops->write == NULL)
2391 /* Attach our ldisc data */
2392 gsm = gsm_alloc_mux();
2396 tty->disc_data = gsm;
2397 tty->receive_room = 65536;
2399 /* Attach the initial passive connection */
2402 ret = gsmld_attach_gsm(tty, gsm);
2404 gsm_cleanup_mux(gsm);
2411 * gsmld_write_wakeup - asynchronous I/O notifier
2414 * Required for the ptys, serial driver etc. since processes
2415 * that attach themselves to the master and rely on ASYNC
2416 * IO must be woken up
2419 static void gsmld_write_wakeup(struct tty_struct *tty)
2421 struct gsm_mux *gsm = tty->disc_data;
2422 unsigned long flags;
2425 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2426 spin_lock_irqsave(&gsm->tx_lock, flags);
2427 gsm_data_kick(gsm, NULL);
2428 if (gsm->tx_bytes < TX_THRESH_LO) {
2429 gsm_dlci_data_sweep(gsm);
2431 spin_unlock_irqrestore(&gsm->tx_lock, flags);
2435 * gsmld_read - read function for tty
2437 * @file: file object
2438 * @buf: userspace buffer pointer
2441 * Perform reads for the line discipline. We are guaranteed that the
2442 * line discipline will not be closed under us but we may get multiple
2443 * parallel readers and must handle this ourselves. We may also get
2444 * a hangup. Always called in user context, may sleep.
2446 * This code must be sure never to sleep through a hangup.
2449 static ssize_t gsmld_read(struct tty_struct *tty, struct file *file,
2450 unsigned char __user *buf, size_t nr)
2456 * gsmld_write - write function for tty
2458 * @file: file object
2459 * @buf: userspace buffer pointer
2462 * Called when the owner of the device wants to send a frame
2463 * itself (or some other control data). The data is transferred
2464 * as-is and must be properly framed and checksummed as appropriate
2465 * by userspace. Frames are either sent whole or not at all as this
2466 * avoids pain user side.
2469 static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
2470 const unsigned char *buf, size_t nr)
2472 int space = tty_write_room(tty);
2474 return tty->ops->write(tty, buf, nr);
2475 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2480 * gsmld_poll - poll method for N_GSM0710
2481 * @tty: terminal device
2482 * @file: file accessing it
2485 * Called when the line discipline is asked to poll() for data or
2486 * for special events. This code is not serialized with respect to
2487 * other events save open/close.
2489 * This code must be sure never to sleep through a hangup.
2490 * Called without the kernel lock held - fine
2493 static unsigned int gsmld_poll(struct tty_struct *tty, struct file *file,
2496 unsigned int mask = 0;
2497 struct gsm_mux *gsm = tty->disc_data;
2499 poll_wait(file, &tty->read_wait, wait);
2500 poll_wait(file, &tty->write_wait, wait);
2501 if (tty_hung_up_p(file))
2503 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
2504 mask |= POLLOUT | POLLWRNORM;
2510 static int gsmld_config(struct tty_struct *tty, struct gsm_mux *gsm,
2511 struct gsm_config *c)
2514 int need_restart = 0;
2516 /* Stuff we don't support yet - UI or I frame transport, windowing */
2517 if ((c->adaption != 1 && c->adaption != 2) || c->k)
2519 /* Check the MRU/MTU range looks sane */
2520 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8)
2524 if (c->encapsulation > 1) /* Basic, advanced, no I */
2526 if (c->initiator > 1)
2528 if (c->i == 0 || c->i > 2) /* UIH and UI only */
2531 * See what is needed for reconfiguration
2535 if (c->t1 != 0 && c->t1 != gsm->t1)
2537 if (c->t2 != 0 && c->t2 != gsm->t2)
2539 if (c->encapsulation != gsm->encoding)
2541 if (c->adaption != gsm->adaption)
2544 if (c->initiator != gsm->initiator)
2546 if (c->mru != gsm->mru)
2548 if (c->mtu != gsm->mtu)
2552 * Close down what is needed, restart and initiate the new
2556 if (need_close || need_restart) {
2557 gsm_dlci_begin_close(gsm->dlci[0]);
2558 /* This will timeout if the link is down due to N2 expiring */
2559 wait_event_interruptible(gsm->event,
2560 gsm->dlci[0]->state == DLCI_CLOSED);
2561 if (signal_pending(current))
2565 gsm_cleanup_mux(gsm);
2567 gsm->initiator = c->initiator;
2570 gsm->encoding = c->encapsulation;
2571 gsm->adaption = c->adaption;
2584 /* FIXME: We need to separate activation/deactivation from adding
2585 and removing from the mux array */
2587 gsm_activate_mux(gsm);
2588 if (gsm->initiator && need_close)
2589 gsm_dlci_begin_open(gsm->dlci[0]);
2593 static int gsmld_ioctl(struct tty_struct *tty, struct file *file,
2594 unsigned int cmd, unsigned long arg)
2596 struct gsm_config c;
2597 struct gsm_mux *gsm = tty->disc_data;
2600 case GSMIOC_GETCONF:
2601 memset(&c, 0, sizeof(c));
2602 c.adaption = gsm->adaption;
2603 c.encapsulation = gsm->encoding;
2604 c.initiator = gsm->initiator;
2607 c.t3 = 0; /* Not supported */
2609 if (gsm->ftype == UIH)
2613 pr_debug("Ftype %d i %d\n", gsm->ftype, c.i);
2617 if (copy_to_user((void *)arg, &c, sizeof(c)))
2620 case GSMIOC_SETCONF:
2621 if (copy_from_user(&c, (void *)arg, sizeof(c)))
2623 return gsmld_config(tty, gsm, &c);
2625 return n_tty_ioctl_helper(tty, file, cmd, arg);
2634 static int gsm_mux_net_open(struct net_device *net)
2636 pr_debug("%s called\n", __func__);
2637 netif_start_queue(net);
2641 static int gsm_mux_net_close(struct net_device *net)
2643 netif_stop_queue(net);
2647 static struct net_device_stats *gsm_mux_net_get_stats(struct net_device *net)
2649 return &((struct gsm_mux_net *)netdev_priv(net))->stats;
2651 static void dlci_net_free(struct gsm_dlci *dlci)
2657 dlci->adaption = dlci->prev_adaption;
2658 dlci->data = dlci->prev_data;
2659 free_netdev(dlci->net);
2662 static void net_free(struct kref *ref)
2664 struct gsm_mux_net *mux_net;
2665 struct gsm_dlci *dlci;
2667 mux_net = container_of(ref, struct gsm_mux_net, ref);
2668 dlci = mux_net->dlci;
2671 unregister_netdev(dlci->net);
2672 dlci_net_free(dlci);
2676 static inline void muxnet_get(struct gsm_mux_net *mux_net)
2678 kref_get(&mux_net->ref);
2681 static inline void muxnet_put(struct gsm_mux_net *mux_net)
2683 kref_put(&mux_net->ref, net_free);
2686 static int gsm_mux_net_start_xmit(struct sk_buff *skb,
2687 struct net_device *net)
2689 struct gsm_mux_net *mux_net = netdev_priv(net);
2690 struct gsm_dlci *dlci = mux_net->dlci;
2691 muxnet_get(mux_net);
2693 skb_queue_head(&dlci->skb_list, skb);
2694 STATS(net).tx_packets++;
2695 STATS(net).tx_bytes += skb->len;
2696 gsm_dlci_data_kick(dlci);
2697 /* And tell the kernel when the last transmit started. */
2698 netif_trans_update(net);
2699 muxnet_put(mux_net);
2700 return NETDEV_TX_OK;
2703 /* called when a packet did not ack after watchdogtimeout */
2704 static void gsm_mux_net_tx_timeout(struct net_device *net)
2706 /* Tell syslog we are hosed. */
2707 dev_dbg(&net->dev, "Tx timed out.\n");
2709 /* Update statistics */
2710 STATS(net).tx_errors++;
2713 static void gsm_mux_rx_netchar(struct gsm_dlci *dlci,
2714 unsigned char *in_buf, int size)
2716 struct net_device *net = dlci->net;
2717 struct sk_buff *skb;
2718 struct gsm_mux_net *mux_net = netdev_priv(net);
2719 muxnet_get(mux_net);
2721 /* Allocate an sk_buff */
2722 skb = dev_alloc_skb(size + NET_IP_ALIGN);
2724 /* We got no receive buffer. */
2725 STATS(net).rx_dropped++;
2726 muxnet_put(mux_net);
2729 skb_reserve(skb, NET_IP_ALIGN);
2730 memcpy(skb_put(skb, size), in_buf, size);
2733 skb->protocol = htons(ETH_P_IP);
2735 /* Ship it off to the kernel */
2738 /* update out statistics */
2739 STATS(net).rx_packets++;
2740 STATS(net).rx_bytes += size;
2741 muxnet_put(mux_net);
2745 static int gsm_change_mtu(struct net_device *net, int new_mtu)
2747 struct gsm_mux_net *mux_net = netdev_priv(net);
2748 if ((new_mtu < 8) || (new_mtu > mux_net->dlci->gsm->mtu))
2754 static void gsm_mux_net_init(struct net_device *net)
2756 static const struct net_device_ops gsm_netdev_ops = {
2757 .ndo_open = gsm_mux_net_open,
2758 .ndo_stop = gsm_mux_net_close,
2759 .ndo_start_xmit = gsm_mux_net_start_xmit,
2760 .ndo_tx_timeout = gsm_mux_net_tx_timeout,
2761 .ndo_get_stats = gsm_mux_net_get_stats,
2762 .ndo_change_mtu = gsm_change_mtu,
2765 net->netdev_ops = &gsm_netdev_ops;
2767 /* fill in the other fields */
2768 net->watchdog_timeo = GSM_NET_TX_TIMEOUT;
2769 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
2770 net->type = ARPHRD_NONE;
2771 net->tx_queue_len = 10;
2775 /* caller holds the dlci mutex */
2776 static void gsm_destroy_network(struct gsm_dlci *dlci)
2778 struct gsm_mux_net *mux_net;
2780 pr_debug("destroy network interface");
2783 mux_net = netdev_priv(dlci->net);
2784 muxnet_put(mux_net);
2788 /* caller holds the dlci mutex */
2789 static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
2793 struct net_device *net;
2794 struct gsm_mux_net *mux_net;
2796 if (!capable(CAP_NET_ADMIN))
2799 /* Already in a non tty mode */
2800 if (dlci->adaption > 2)
2803 if (nc->protocol != htons(ETH_P_IP))
2804 return -EPROTONOSUPPORT;
2806 if (nc->adaption != 3 && nc->adaption != 4)
2807 return -EPROTONOSUPPORT;
2809 pr_debug("create network interface");
2812 if (nc->if_name[0] != '\0')
2813 netname = nc->if_name;
2814 net = alloc_netdev(sizeof(struct gsm_mux_net), netname,
2815 NET_NAME_UNKNOWN, gsm_mux_net_init);
2817 pr_err("alloc_netdev failed");
2820 net->mtu = dlci->gsm->mtu;
2821 mux_net = netdev_priv(net);
2822 mux_net->dlci = dlci;
2823 kref_init(&mux_net->ref);
2824 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */
2826 /* reconfigure dlci for network */
2827 dlci->prev_adaption = dlci->adaption;
2828 dlci->prev_data = dlci->data;
2829 dlci->adaption = nc->adaption;
2830 dlci->data = gsm_mux_rx_netchar;
2833 pr_debug("register netdev");
2834 retval = register_netdev(net);
2836 pr_err("network register fail %d\n", retval);
2837 dlci_net_free(dlci);
2840 return net->ifindex; /* return network index */
2843 /* Line discipline for real tty */
2844 static struct tty_ldisc_ops tty_ldisc_packet = {
2845 .owner = THIS_MODULE,
2846 .magic = TTY_LDISC_MAGIC,
2849 .close = gsmld_close,
2850 .flush_buffer = gsmld_flush_buffer,
2852 .write = gsmld_write,
2853 .ioctl = gsmld_ioctl,
2855 .receive_buf = gsmld_receive_buf,
2856 .write_wakeup = gsmld_write_wakeup
2865 static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk)
2868 struct gsm_control *ctrl;
2871 modembits[0] = (dlci->addr << 2) | 2 | EA; /* DLCI, Valid, EA */
2872 modembits[1] = (gsm_encode_modem(dlci) << 1) | EA;
2874 modembits[2] = (brk << 4) | 2 | EA; /* Length, Break, EA */
2877 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len);
2880 return gsm_control_wait(dlci->gsm, ctrl);
2883 static int gsm_carrier_raised(struct tty_port *port)
2885 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2886 struct gsm_mux *gsm = dlci->gsm;
2888 /* Not yet open so no carrier info */
2889 if (dlci->state != DLCI_OPEN)
2895 * Basic mode with control channel in ADM mode may not respond
2896 * to CMD_MSC at all and modem_rx is empty.
2898 if (gsm->encoding == 0 && gsm->dlci[0]->mode == DLCI_MODE_ADM &&
2902 return dlci->modem_rx & TIOCM_CD;
2905 static void gsm_dtr_rts(struct tty_port *port, int onoff)
2907 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2908 unsigned int modem_tx = dlci->modem_tx;
2910 modem_tx |= TIOCM_DTR | TIOCM_RTS;
2912 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
2913 if (modem_tx != dlci->modem_tx) {
2914 dlci->modem_tx = modem_tx;
2915 gsmtty_modem_update(dlci, 0);
2919 static const struct tty_port_operations gsm_port_ops = {
2920 .carrier_raised = gsm_carrier_raised,
2921 .dtr_rts = gsm_dtr_rts,
2922 .destruct = gsm_dlci_free,
2925 static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty)
2927 struct gsm_mux *gsm;
2928 struct gsm_dlci *dlci;
2929 unsigned int line = tty->index;
2930 unsigned int mux = line >> 6;
2938 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
2939 if (gsm_mux[mux] == NULL)
2941 if (line == 0 || line > 61) /* 62/63 reserved */
2946 /* If DLCI 0 is not yet fully open return an error.
2947 This is ok from a locking
2948 perspective as we don't have to worry about this
2950 mutex_lock(&gsm->mutex);
2951 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN) {
2952 mutex_unlock(&gsm->mutex);
2955 dlci = gsm->dlci[line];
2958 dlci = gsm_dlci_alloc(gsm, line);
2961 mutex_unlock(&gsm->mutex);
2964 ret = tty_port_install(&dlci->port, driver, tty);
2968 mutex_unlock(&gsm->mutex);
2973 dlci_get(gsm->dlci[0]);
2975 tty->driver_data = dlci;
2976 mutex_unlock(&gsm->mutex);
2981 static int gsmtty_open(struct tty_struct *tty, struct file *filp)
2983 struct gsm_dlci *dlci = tty->driver_data;
2984 struct tty_port *port = &dlci->port;
2987 tty_port_tty_set(port, tty);
2990 /* We could in theory open and close before we wait - eg if we get
2991 a DM straight back. This is ok as that will have caused a hangup */
2992 tty_port_set_initialized(port, 1);
2993 /* Start sending off SABM messages */
2994 gsm_dlci_begin_open(dlci);
2995 /* And wait for virtual carrier */
2996 return tty_port_block_til_ready(port, tty, filp);
2999 static void gsmtty_close(struct tty_struct *tty, struct file *filp)
3001 struct gsm_dlci *dlci = tty->driver_data;
3002 struct gsm_mux *gsm;
3006 if (dlci->state == DLCI_CLOSED)
3008 mutex_lock(&dlci->mutex);
3009 gsm_destroy_network(dlci);
3010 mutex_unlock(&dlci->mutex);
3012 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
3014 gsm_dlci_begin_close(dlci);
3015 if (tty_port_initialized(&dlci->port) && C_HUPCL(tty))
3016 tty_port_lower_dtr_rts(&dlci->port);
3017 tty_port_close_end(&dlci->port, tty);
3018 tty_port_tty_set(&dlci->port, NULL);
3022 static void gsmtty_hangup(struct tty_struct *tty)
3024 struct gsm_dlci *dlci = tty->driver_data;
3025 if (dlci->state == DLCI_CLOSED)
3027 tty_port_hangup(&dlci->port);
3028 gsm_dlci_begin_close(dlci);
3031 static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf,
3035 struct gsm_dlci *dlci = tty->driver_data;
3036 if (dlci->state == DLCI_CLOSED)
3038 /* Stuff the bytes into the fifo queue */
3039 sent = kfifo_in_locked(dlci->fifo, buf, len, &dlci->lock);
3040 /* Need to kick the channel */
3041 gsm_dlci_data_kick(dlci);
3045 static int gsmtty_write_room(struct tty_struct *tty)
3047 struct gsm_dlci *dlci = tty->driver_data;
3048 if (dlci->state == DLCI_CLOSED)
3050 return TX_SIZE - kfifo_len(dlci->fifo);
3053 static int gsmtty_chars_in_buffer(struct tty_struct *tty)
3055 struct gsm_dlci *dlci = tty->driver_data;
3056 if (dlci->state == DLCI_CLOSED)
3058 return kfifo_len(dlci->fifo);
3061 static void gsmtty_flush_buffer(struct tty_struct *tty)
3063 struct gsm_dlci *dlci = tty->driver_data;
3064 if (dlci->state == DLCI_CLOSED)
3066 /* Caution needed: If we implement reliable transport classes
3067 then the data being transmitted can't simply be junked once
3068 it has first hit the stack. Until then we can just blow it
3070 kfifo_reset(dlci->fifo);
3071 /* Need to unhook this DLCI from the transmit queue logic */
3074 static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
3076 /* The FIFO handles the queue so the kernel will do the right
3077 thing waiting on chars_in_buffer before calling us. No work
3081 static int gsmtty_tiocmget(struct tty_struct *tty)
3083 struct gsm_dlci *dlci = tty->driver_data;
3084 if (dlci->state == DLCI_CLOSED)
3086 return dlci->modem_rx;
3089 static int gsmtty_tiocmset(struct tty_struct *tty,
3090 unsigned int set, unsigned int clear)
3092 struct gsm_dlci *dlci = tty->driver_data;
3093 unsigned int modem_tx = dlci->modem_tx;
3095 if (dlci->state == DLCI_CLOSED)
3100 if (modem_tx != dlci->modem_tx) {
3101 dlci->modem_tx = modem_tx;
3102 return gsmtty_modem_update(dlci, 0);
3108 static int gsmtty_ioctl(struct tty_struct *tty,
3109 unsigned int cmd, unsigned long arg)
3111 struct gsm_dlci *dlci = tty->driver_data;
3112 struct gsm_netconfig nc;
3115 if (dlci->state == DLCI_CLOSED)
3118 case GSMIOC_ENABLE_NET:
3119 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc)))
3121 nc.if_name[IFNAMSIZ-1] = '\0';
3122 /* return net interface index or error code */
3123 mutex_lock(&dlci->mutex);
3124 index = gsm_create_network(dlci, &nc);
3125 mutex_unlock(&dlci->mutex);
3126 if (copy_to_user((void __user *)arg, &nc, sizeof(nc)))
3129 case GSMIOC_DISABLE_NET:
3130 if (!capable(CAP_NET_ADMIN))
3132 mutex_lock(&dlci->mutex);
3133 gsm_destroy_network(dlci);
3134 mutex_unlock(&dlci->mutex);
3137 return -ENOIOCTLCMD;
3141 static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old)
3143 struct gsm_dlci *dlci = tty->driver_data;
3144 if (dlci->state == DLCI_CLOSED)
3146 /* For the moment its fixed. In actual fact the speed information
3147 for the virtual channel can be propogated in both directions by
3148 the RPN control message. This however rapidly gets nasty as we
3149 then have to remap modem signals each way according to whether
3150 our virtual cable is null modem etc .. */
3151 tty_termios_copy_hw(&tty->termios, old);
3154 static void gsmtty_throttle(struct tty_struct *tty)
3156 struct gsm_dlci *dlci = tty->driver_data;
3157 if (dlci->state == DLCI_CLOSED)
3160 dlci->modem_tx &= ~TIOCM_DTR;
3161 dlci->throttled = 1;
3162 /* Send an MSC with DTR cleared */
3163 gsmtty_modem_update(dlci, 0);
3166 static void gsmtty_unthrottle(struct tty_struct *tty)
3168 struct gsm_dlci *dlci = tty->driver_data;
3169 if (dlci->state == DLCI_CLOSED)
3172 dlci->modem_tx |= TIOCM_DTR;
3173 dlci->throttled = 0;
3174 /* Send an MSC with DTR set */
3175 gsmtty_modem_update(dlci, 0);
3178 static int gsmtty_break_ctl(struct tty_struct *tty, int state)
3180 struct gsm_dlci *dlci = tty->driver_data;
3181 int encode = 0; /* Off */
3182 if (dlci->state == DLCI_CLOSED)
3185 if (state == -1) /* "On indefinitely" - we can't encode this
3188 else if (state > 0) {
3189 encode = state / 200; /* mS to encoding */
3191 encode = 0x0F; /* Best effort */
3193 return gsmtty_modem_update(dlci, encode);
3196 static void gsmtty_cleanup(struct tty_struct *tty)
3198 struct gsm_dlci *dlci = tty->driver_data;
3199 struct gsm_mux *gsm = dlci->gsm;
3202 dlci_put(gsm->dlci[0]);
3206 /* Virtual ttys for the demux */
3207 static const struct tty_operations gsmtty_ops = {
3208 .install = gsmtty_install,
3209 .open = gsmtty_open,
3210 .close = gsmtty_close,
3211 .write = gsmtty_write,
3212 .write_room = gsmtty_write_room,
3213 .chars_in_buffer = gsmtty_chars_in_buffer,
3214 .flush_buffer = gsmtty_flush_buffer,
3215 .ioctl = gsmtty_ioctl,
3216 .throttle = gsmtty_throttle,
3217 .unthrottle = gsmtty_unthrottle,
3218 .set_termios = gsmtty_set_termios,
3219 .hangup = gsmtty_hangup,
3220 .wait_until_sent = gsmtty_wait_until_sent,
3221 .tiocmget = gsmtty_tiocmget,
3222 .tiocmset = gsmtty_tiocmset,
3223 .break_ctl = gsmtty_break_ctl,
3224 .cleanup = gsmtty_cleanup,
3229 static int __init gsm_init(void)
3231 /* Fill in our line protocol discipline, and register it */
3232 int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet);
3234 pr_err("n_gsm: can't register line discipline (err = %d)\n",
3239 gsm_tty_driver = alloc_tty_driver(256);
3240 if (!gsm_tty_driver) {
3241 tty_unregister_ldisc(N_GSM0710);
3242 pr_err("gsm_init: tty allocation failed.\n");
3245 gsm_tty_driver->driver_name = "gsmtty";
3246 gsm_tty_driver->name = "gsmtty";
3247 gsm_tty_driver->major = 0; /* Dynamic */
3248 gsm_tty_driver->minor_start = 0;
3249 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
3250 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
3251 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV
3252 | TTY_DRIVER_HARDWARE_BREAK;
3253 gsm_tty_driver->init_termios = tty_std_termios;
3255 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
3256 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
3258 spin_lock_init(&gsm_mux_lock);
3260 if (tty_register_driver(gsm_tty_driver)) {
3261 put_tty_driver(gsm_tty_driver);
3262 tty_unregister_ldisc(N_GSM0710);
3263 pr_err("gsm_init: tty registration failed.\n");
3266 pr_debug("gsm_init: loaded as %d,%d.\n",
3267 gsm_tty_driver->major, gsm_tty_driver->minor_start);
3271 static void __exit gsm_exit(void)
3273 int status = tty_unregister_ldisc(N_GSM0710);
3275 pr_err("n_gsm: can't unregister line discipline (err = %d)\n",
3277 tty_unregister_driver(gsm_tty_driver);
3278 put_tty_driver(gsm_tty_driver);
3281 module_init(gsm_init);
3282 module_exit(gsm_exit);
3285 MODULE_LICENSE("GPL");
3286 MODULE_ALIAS_LDISC(N_GSM0710);