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 #define GSM_NET_TX_TIMEOUT (HZ*10)
90 * struct gsm_mux_net - network interface
91 * @struct gsm_dlci* dlci
92 * @struct net_device_stats stats;
94 * Created when net interface is initialized.
98 struct gsm_dlci *dlci;
99 struct net_device_stats stats;
102 #define STATS(net) (((struct gsm_mux_net *)netdev_priv(net))->stats)
105 * Each block of data we have queued to go out is in the form of
106 * a gsm_msg which holds everything we need in a link layer independent
111 struct list_head list;
112 u8 addr; /* DLCI address + flags */
113 u8 ctrl; /* Control byte + flags */
114 unsigned int len; /* Length of data block (can be zero) */
115 unsigned char *data; /* Points into buffer but not at the start */
116 unsigned char buffer[0];
120 * Each active data link has a gsm_dlci structure associated which ties
121 * the link layer to an optional tty (if the tty side is open). To avoid
122 * complexity right now these are only ever freed up when the mux is
125 * At the moment we don't free DLCI objects until the mux is torn down
126 * this avoid object life time issues but might be worth review later.
133 #define DLCI_CLOSED 0
134 #define DLCI_OPENING 1 /* Sending SABM not seen UA */
135 #define DLCI_OPEN 2 /* SABM/UA complete */
136 #define DLCI_CLOSING 3 /* Sending DISC not seen UA/DM */
140 spinlock_t lock; /* Protects the internal state */
141 struct timer_list t1; /* Retransmit timer for SABM and UA */
143 /* Uplink tty if active */
144 struct tty_port port; /* The tty bound to this DLCI if there is one */
145 struct kfifo *fifo; /* Queue fifo for the DLCI */
146 struct kfifo _fifo; /* For new fifo API porting only */
147 int adaption; /* Adaption layer in use */
149 u32 modem_rx; /* Our incoming virtual modem lines */
150 u32 modem_tx; /* Our outgoing modem lines */
151 int dead; /* Refuse re-open */
153 int throttled; /* Private copy of throttle state */
154 int constipated; /* Throttle status for outgoing */
156 struct sk_buff *skb; /* Frame being sent */
157 struct sk_buff_head skb_list; /* Queued frames */
158 /* Data handling callback */
159 void (*data)(struct gsm_dlci *dlci, u8 *data, int len);
160 void (*prev_data)(struct gsm_dlci *dlci, u8 *data, int len);
161 struct net_device *net; /* network interface, if created */
164 /* DLCI 0, 62/63 are special or reseved see gsmtty_open */
169 * DLCI 0 is used to pass control blocks out of band of the data
170 * flow (and with a higher link priority). One command can be outstanding
171 * at a time and we use this structure to manage them. They are created
172 * and destroyed by the user context, and updated by the receive paths
177 u8 cmd; /* Command we are issuing */
178 u8 *data; /* Data for the command in case we retransmit */
179 int len; /* Length of block for retransmission */
180 int done; /* Done flag */
181 int error; /* Error if any */
185 * Each GSM mux we have is represented by this structure. If we are
186 * operating as an ldisc then we use this structure as our ldisc
187 * state. We need to sort out lifetimes and locking with respect
188 * to the gsm mux array. For now we don't free DLCI objects that
189 * have been instantiated until the mux itself is terminated.
191 * To consider further: tty open versus mux shutdown.
195 struct tty_struct *tty; /* The tty our ldisc is bound to */
200 /* Events on the GSM channel */
201 wait_queue_head_t event;
203 /* Bits for GSM mode decoding */
210 #define GSM_ADDRESS 2
211 #define GSM_CONTROL 3
215 #define GSM_OVERRUN 7
220 unsigned int address;
227 u8 *txframe; /* TX framing buffer */
229 /* Methods for the receiver side */
230 void (*receive)(struct gsm_mux *gsm, u8 ch);
231 void (*error)(struct gsm_mux *gsm, u8 ch, u8 flag);
232 /* And transmit side */
233 int (*output)(struct gsm_mux *mux, u8 *data, int len);
238 int initiator; /* Did we initiate connection */
239 int dead; /* Has the mux been shut down */
240 struct gsm_dlci *dlci[NUM_DLCI];
241 int constipated; /* Asked by remote to shut up */
244 unsigned int tx_bytes; /* TX data outstanding */
245 #define TX_THRESH_HI 8192
246 #define TX_THRESH_LO 2048
247 struct list_head tx_list; /* Pending data packets */
249 /* Control messages */
250 struct timer_list t2_timer; /* Retransmit timer for commands */
251 int cretries; /* Command retry counter */
252 struct gsm_control *pending_cmd;/* Our current pending command */
253 spinlock_t control_lock; /* Protects the pending command */
256 int adaption; /* 1 or 2 supported */
257 u8 ftype; /* UI or UIH */
258 int t1, t2; /* Timers in 1/100th of a sec */
259 int n2; /* Retry count */
261 /* Statistics (not currently exposed) */
262 unsigned long bad_fcs;
263 unsigned long malformed;
264 unsigned long io_error;
265 unsigned long bad_size;
266 unsigned long unsupported;
271 * Mux objects - needed so that we can translate a tty index into the
272 * relevant mux and DLCI.
275 #define MAX_MUX 4 /* 256 minors */
276 static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */
277 static spinlock_t gsm_mux_lock;
279 static struct tty_driver *gsm_tty_driver;
282 * This section of the driver logic implements the GSM encodings
283 * both the basic and the 'advanced'. Reliable transport is not
291 /* I is special: the rest are ..*/
302 /* Channel commands */
304 #define CMD_TEST 0x11
307 #define CMD_FCOFF 0x31
310 #define CMD_FCON 0x51
315 /* Virtual modem bits */
322 #define GSM0_SOF 0xF9
323 #define GSM1_SOF 0x7E
324 #define GSM1_ESCAPE 0x7D
325 #define GSM1_ESCAPE_BITS 0x20
329 static const struct tty_port_operations gsm_port_ops;
332 * CRC table for GSM 0710
335 static const u8 gsm_fcs8[256] = {
336 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75,
337 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B,
338 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69,
339 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67,
340 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D,
341 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43,
342 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51,
343 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F,
344 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05,
345 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B,
346 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19,
347 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17,
348 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D,
349 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33,
350 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21,
351 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F,
352 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95,
353 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B,
354 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89,
355 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87,
356 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD,
357 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3,
358 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1,
359 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF,
360 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5,
361 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB,
362 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9,
363 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7,
364 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD,
365 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3,
366 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1,
367 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF
370 #define INIT_FCS 0xFF
371 #define GOOD_FCS 0xCF
374 * gsm_fcs_add - update FCS
378 * Update the FCS to include c. Uses the algorithm in the specification
382 static inline u8 gsm_fcs_add(u8 fcs, u8 c)
384 return gsm_fcs8[fcs ^ c];
388 * gsm_fcs_add_block - update FCS for a block
391 * @len: length of buffer
393 * Update the FCS to include c. Uses the algorithm in the specification
397 static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len)
400 fcs = gsm_fcs8[fcs ^ *c++];
405 * gsm_read_ea - read a byte into an EA
406 * @val: variable holding value
407 * c: byte going into the EA
409 * Processes one byte of an EA. Updates the passed variable
410 * and returns 1 if the EA is now completely read
413 static int gsm_read_ea(unsigned int *val, u8 c)
415 /* Add the next 7 bits into the value */
418 /* Was this the last byte of the EA 1 = yes*/
423 * gsm_encode_modem - encode modem data bits
424 * @dlci: DLCI to encode from
426 * Returns the correct GSM encoded modem status bits (6 bit field) for
427 * the current status of the DLCI and attached tty object
430 static u8 gsm_encode_modem(const struct gsm_dlci *dlci)
433 /* FC is true flow control not modem bits */
436 if (dlci->modem_tx & TIOCM_DTR)
437 modembits |= MDM_RTC;
438 if (dlci->modem_tx & TIOCM_RTS)
439 modembits |= MDM_RTR;
440 if (dlci->modem_tx & TIOCM_RI)
442 if (dlci->modem_tx & TIOCM_CD)
448 * gsm_print_packet - display a frame for debug
449 * @hdr: header to print before decode
450 * @addr: address EA from the frame
451 * @cr: C/R bit from the frame
452 * @control: control including PF bit
453 * @data: following data bytes
454 * @dlen: length of data
456 * Displays a packet in human readable format for debugging purposes. The
457 * style is based on amateur radio LAP-B dump display.
460 static void gsm_print_packet(const char *hdr, int addr, int cr,
461 u8 control, const u8 *data, int dlen)
466 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]);
468 switch (control & ~PF) {
488 if (!(control & 0x01)) {
489 pr_cont("I N(S)%d N(R)%d",
490 (control & 0x0E) >> 1, (control & 0xE0) >> 5);
491 } else switch (control & 0x0F) {
493 pr_cont("RR(%d)", (control & 0xE0) >> 5);
496 pr_cont("RNR(%d)", (control & 0xE0) >> 5);
499 pr_cont("REJ(%d)", (control & 0xE0) >> 5);
502 pr_cont("[%02X]", control);
518 pr_cont("%02X ", *data++);
527 * Link level transmission side
531 * gsm_stuff_packet - bytestuff a packet
534 * @len: length of input
536 * Expand a buffer by bytestuffing it. The worst case size change
537 * is doubling and the caller is responsible for handing out
538 * suitable sized buffers.
541 static int gsm_stuff_frame(const u8 *input, u8 *output, int len)
545 if (*input == GSM1_SOF || *input == GSM1_ESCAPE
546 || *input == XON || *input == XOFF) {
547 *output++ = GSM1_ESCAPE;
548 *output++ = *input++ ^ GSM1_ESCAPE_BITS;
551 *output++ = *input++;
558 * gsm_send - send a control frame
560 * @addr: address for control frame
561 * @cr: command/response bit
562 * @control: control byte including PF bit
564 * Format up and transmit a control frame. These do not go via the
565 * queueing logic as they should be transmitted ahead of data when
568 * FIXME: Lock versus data TX path
571 static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control)
578 switch (gsm->encoding) {
581 cbuf[1] = (addr << 2) | (cr << 1) | EA;
583 cbuf[3] = EA; /* Length of data = 0 */
584 cbuf[4] = 0xFF - gsm_fcs_add_block(INIT_FCS, cbuf + 1, 3);
590 /* Control frame + packing (but not frame stuffing) in mode 1 */
591 ibuf[0] = (addr << 2) | (cr << 1) | EA;
593 ibuf[2] = 0xFF - gsm_fcs_add_block(INIT_FCS, ibuf, 2);
594 /* Stuffing may double the size worst case */
595 len = gsm_stuff_frame(ibuf, cbuf + 1, 3);
596 /* Now add the SOF markers */
598 cbuf[len + 1] = GSM1_SOF;
599 /* FIXME: we can omit the lead one in many cases */
606 spin_lock_irqsave(&gsm->tx_lock, flags);
607 gsm->output(gsm, cbuf, len);
608 spin_unlock_irqrestore(&gsm->tx_lock, flags);
609 gsm_print_packet("-->", addr, cr, control, NULL, 0);
613 * gsm_response - send a control response
615 * @addr: address for control frame
616 * @control: control byte including PF bit
618 * Format up and transmit a link level response frame.
621 static inline void gsm_response(struct gsm_mux *gsm, int addr, int control)
623 gsm_send(gsm, addr, 0, control);
627 * gsm_command - send a control command
629 * @addr: address for control frame
630 * @control: control byte including PF bit
632 * Format up and transmit a link level command frame.
635 static inline void gsm_command(struct gsm_mux *gsm, int addr, int control)
637 gsm_send(gsm, addr, 1, control);
640 /* Data transmission */
642 #define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */
645 * gsm_data_alloc - allocate data frame
647 * @addr: DLCI address
648 * @len: length excluding header and FCS
649 * @ctrl: control byte
651 * Allocate a new data buffer for sending frames with data. Space is left
652 * at the front for header bytes but that is treated as an implementation
653 * detail and not for the high level code to use
656 static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
659 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN,
663 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */
667 INIT_LIST_HEAD(&m->list);
672 * gsm_data_kick - poke the queue
675 * The tty device has called us to indicate that room has appeared in
676 * the transmit queue. Ram more data into the pipe if we have any
677 * If we have been flow-stopped by a CMD_FCOFF, then we can only
678 * send messages on DLCI0 until CMD_FCON
680 * FIXME: lock against link layer control transmissions
683 static void gsm_data_kick(struct gsm_mux *gsm)
685 struct gsm_msg *msg, *nmsg;
689 list_for_each_entry_safe(msg, nmsg, &gsm->tx_list, list) {
690 if (gsm->constipated && msg->addr)
692 if (gsm->encoding != 0) {
693 gsm->txframe[0] = GSM1_SOF;
694 len = gsm_stuff_frame(msg->data,
695 gsm->txframe + 1, msg->len);
696 gsm->txframe[len + 1] = GSM1_SOF;
699 gsm->txframe[0] = GSM0_SOF;
700 memcpy(gsm->txframe + 1 , msg->data, msg->len);
701 gsm->txframe[msg->len + 1] = GSM0_SOF;
706 print_hex_dump_bytes("gsm_data_kick: ",
710 if (gsm->output(gsm, gsm->txframe + skip_sof,
713 /* FIXME: Can eliminate one SOF in many more cases */
714 gsm->tx_bytes -= msg->len;
715 /* For a burst of frames skip the extra SOF within the
719 list_del(&msg->list);
725 * __gsm_data_queue - queue a UI or UIH frame
726 * @dlci: DLCI sending the data
727 * @msg: message queued
729 * Add data to the transmit queue and try and get stuff moving
730 * out of the mux tty if not already doing so. The Caller must hold
734 static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
736 struct gsm_mux *gsm = dlci->gsm;
738 u8 *fcs = dp + msg->len;
740 /* Fill in the header */
741 if (gsm->encoding == 0) {
743 *--dp = (msg->len << 1) | EA;
745 *--dp = (msg->len >> 7); /* bits 7 - 15 */
746 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */
752 *--dp = (msg->addr << 2) | 2 | EA;
754 *--dp = (msg->addr << 2) | EA;
755 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp);
756 /* Ugly protocol layering violation */
757 if (msg->ctrl == UI || msg->ctrl == (UI|PF))
758 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len);
761 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl,
762 msg->data, msg->len);
764 /* Move the header back and adjust the length, also allow for the FCS
765 now tacked on the end */
766 msg->len += (msg->data - dp) + 1;
769 /* Add to the actual output queue */
770 list_add_tail(&msg->list, &gsm->tx_list);
771 gsm->tx_bytes += msg->len;
776 * gsm_data_queue - queue a UI or UIH frame
777 * @dlci: DLCI sending the data
778 * @msg: message queued
780 * Add data to the transmit queue and try and get stuff moving
781 * out of the mux tty if not already doing so. Take the
782 * the gsm tx lock and dlci lock.
785 static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
788 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
789 __gsm_data_queue(dlci, msg);
790 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
794 * gsm_dlci_data_output - try and push data out of a DLCI
796 * @dlci: the DLCI to pull data from
798 * Pull data from a DLCI and send it into the transmit queue if there
799 * is data. Keep to the MRU of the mux. This path handles the usual tty
800 * interface which is a byte stream with optional modem data.
802 * Caller must hold the tx_lock of the mux.
805 static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci)
809 int len, total_size, size;
810 int h = dlci->adaption - 1;
814 len = kfifo_len(dlci->fifo);
818 /* MTU/MRU count only the data bits */
824 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
825 /* FIXME: need a timer or something to kick this so it can't
826 get stuck with no work outstanding and no buffer free */
830 switch (dlci->adaption) {
831 case 1: /* Unstructured */
833 case 2: /* Unstructed with modem bits. Always one byte as we never
834 send inline break data */
835 *dp++ = gsm_encode_modem(dlci);
838 WARN_ON(kfifo_out_locked(dlci->fifo, dp , len, &dlci->lock) != len);
839 __gsm_data_queue(dlci, msg);
842 /* Bytes of data we used up */
847 * gsm_dlci_data_output_framed - try and push data out of a DLCI
849 * @dlci: the DLCI to pull data from
851 * Pull data from a DLCI and send it into the transmit queue if there
852 * is data. Keep to the MRU of the mux. This path handles framed data
853 * queued as skbuffs to the DLCI.
855 * Caller must hold the tx_lock of the mux.
858 static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
859 struct gsm_dlci *dlci)
864 int last = 0, first = 0;
867 /* One byte per frame is used for B/F flags */
868 if (dlci->adaption == 4)
871 /* dlci->skb is locked by tx_lock */
872 if (dlci->skb == NULL) {
873 dlci->skb = skb_dequeue_tail(&dlci->skb_list);
874 if (dlci->skb == NULL)
878 len = dlci->skb->len + overhead;
880 /* MTU/MRU count only the data bits */
881 if (len > gsm->mtu) {
882 if (dlci->adaption == 3) {
883 /* Over long frame, bin it */
884 dev_kfree_skb_any(dlci->skb);
892 size = len + overhead;
893 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
895 /* FIXME: need a timer or something to kick this so it can't
896 get stuck with no work outstanding and no buffer free */
898 skb_queue_tail(&dlci->skb_list, dlci->skb);
904 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */
905 /* Flag byte to carry the start/end info */
906 *dp++ = last << 7 | first << 6 | 1; /* EA */
909 memcpy(dp, dlci->skb->data, len);
910 skb_pull(dlci->skb, len);
911 __gsm_data_queue(dlci, msg);
913 dev_kfree_skb_any(dlci->skb);
920 * gsm_dlci_data_sweep - look for data to send
923 * Sweep the GSM mux channels in priority order looking for ones with
924 * data to send. We could do with optimising this scan a bit. We aim
925 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit
926 * TX_THRESH_LO we get called again
928 * FIXME: We should round robin between groups and in theory you can
929 * renegotiate DLCI priorities with optional stuff. Needs optimising.
932 static void gsm_dlci_data_sweep(struct gsm_mux *gsm)
935 /* Priority ordering: We should do priority with RR of the groups */
938 while (i < NUM_DLCI) {
939 struct gsm_dlci *dlci;
941 if (gsm->tx_bytes > TX_THRESH_HI)
944 if (dlci == NULL || dlci->constipated) {
948 if (dlci->adaption < 3 && !dlci->net)
949 len = gsm_dlci_data_output(gsm, dlci);
951 len = gsm_dlci_data_output_framed(gsm, dlci);
954 /* DLCI empty - try the next */
961 * gsm_dlci_data_kick - transmit if possible
962 * @dlci: DLCI to kick
964 * Transmit data from this DLCI if the queue is empty. We can't rely on
965 * a tty wakeup except when we filled the pipe so we need to fire off
966 * new data ourselves in other cases.
969 static void gsm_dlci_data_kick(struct gsm_dlci *dlci)
974 if (dlci->constipated)
977 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
978 /* If we have nothing running then we need to fire up */
979 sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO);
980 if (dlci->gsm->tx_bytes == 0) {
982 gsm_dlci_data_output_framed(dlci->gsm, dlci);
984 gsm_dlci_data_output(dlci->gsm, dlci);
987 gsm_dlci_data_sweep(dlci->gsm);
988 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
992 * Control message processing
997 * gsm_control_reply - send a response frame to a control
999 * @cmd: the command to use
1000 * @data: data to follow encoded info
1001 * @dlen: length of data
1003 * Encode up and queue a UI/UIH frame containing our response.
1006 static void gsm_control_reply(struct gsm_mux *gsm, int cmd, u8 *data,
1009 struct gsm_msg *msg;
1010 msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype);
1013 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */
1014 msg->data[1] = (dlen << 1) | EA;
1015 memcpy(msg->data + 2, data, dlen);
1016 gsm_data_queue(gsm->dlci[0], msg);
1020 * gsm_process_modem - process received modem status
1021 * @tty: virtual tty bound to the DLCI
1022 * @dlci: DLCI to affect
1023 * @modem: modem bits (full EA)
1025 * Used when a modem control message or line state inline in adaption
1026 * layer 2 is processed. Sort out the local modem state and throttles
1029 static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
1030 u32 modem, int clen)
1036 /* The modem status command can either contain one octet (v.24 signals)
1037 or two octets (v.24 signals + break signals). The length field will
1038 either be 2 or 3 respectively. This is specified in section
1039 5.4.6.3.7 of the 27.010 mux spec. */
1042 modem = modem & 0x7f;
1045 modem = (modem >> 7) & 0x7f;
1048 /* Flow control/ready to communicate */
1049 fc = (modem & MDM_FC) || !(modem & MDM_RTR);
1050 if (fc && !dlci->constipated) {
1051 /* Need to throttle our output on this device */
1052 dlci->constipated = 1;
1053 } else if (!fc && dlci->constipated) {
1054 dlci->constipated = 0;
1055 gsm_dlci_data_kick(dlci);
1058 /* Map modem bits */
1059 if (modem & MDM_RTC)
1060 mlines |= TIOCM_DSR | TIOCM_DTR;
1061 if (modem & MDM_RTR)
1062 mlines |= TIOCM_RTS | TIOCM_CTS;
1068 /* Carrier drop -> hangup */
1070 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD))
1071 if (!(tty->termios.c_cflag & CLOCAL))
1075 tty_insert_flip_char(&dlci->port, 0, TTY_BREAK);
1076 dlci->modem_rx = mlines;
1080 * gsm_control_modem - modem status received
1082 * @data: data following command
1083 * @clen: command length
1085 * We have received a modem status control message. This is used by
1086 * the GSM mux protocol to pass virtual modem line status and optionally
1087 * to indicate break signals. Unpack it, convert to Linux representation
1088 * and if need be stuff a break message down the tty.
1091 static void gsm_control_modem(struct gsm_mux *gsm, u8 *data, int clen)
1093 unsigned int addr = 0;
1094 unsigned int modem = 0;
1095 struct gsm_dlci *dlci;
1098 struct tty_struct *tty;
1100 while (gsm_read_ea(&addr, *dp++) == 0) {
1105 /* Must be at least one byte following the EA */
1111 /* Closed port, or invalid ? */
1112 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1114 dlci = gsm->dlci[addr];
1116 while (gsm_read_ea(&modem, *dp++) == 0) {
1121 tty = tty_port_tty_get(&dlci->port);
1122 gsm_process_modem(tty, dlci, modem, clen);
1127 gsm_control_reply(gsm, CMD_MSC, data, clen);
1131 * gsm_control_rls - remote line status
1134 * @clen: data length
1136 * The modem sends us a two byte message on the control channel whenever
1137 * it wishes to send us an error state from the virtual link. Stuff
1138 * this into the uplink tty if present
1141 static void gsm_control_rls(struct gsm_mux *gsm, u8 *data, int clen)
1143 struct tty_port *port;
1144 struct tty_struct *tty;
1145 unsigned int addr = 0 ;
1150 while (gsm_read_ea(&addr, *dp++) == 0) {
1155 /* Must be at least one byte following ea */
1160 /* Closed port, or invalid ? */
1161 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1165 if ((bits & 1) == 0)
1168 port = &gsm->dlci[addr]->port;
1171 tty_insert_flip_char(port, 0, TTY_OVERRUN);
1173 tty_insert_flip_char(port, 0, TTY_PARITY);
1175 tty_insert_flip_char(port, 0, TTY_FRAME);
1177 /* See if we have an uplink tty */
1178 tty = tty_port_tty_get(port);
1180 tty_flip_buffer_push(tty);
1183 gsm_control_reply(gsm, CMD_RLS, data, clen);
1186 static void gsm_dlci_begin_close(struct gsm_dlci *dlci);
1189 * gsm_control_message - DLCI 0 control processing
1191 * @command: the command EA
1192 * @data: data beyond the command/length EAs
1195 * Input processor for control messages from the other end of the link.
1196 * Processes the incoming request and queues a response frame or an
1197 * NSC response if not supported
1200 static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
1204 unsigned long flags;
1208 struct gsm_dlci *dlci = gsm->dlci[0];
1209 /* Modem wishes to close down */
1213 gsm_dlci_begin_close(dlci);
1218 /* Modem wishes to test, reply with the data */
1219 gsm_control_reply(gsm, CMD_TEST, data, clen);
1222 /* Modem can accept data again */
1223 gsm->constipated = 0;
1224 gsm_control_reply(gsm, CMD_FCON, NULL, 0);
1225 /* Kick the link in case it is idling */
1226 spin_lock_irqsave(&gsm->tx_lock, flags);
1228 spin_unlock_irqrestore(&gsm->tx_lock, flags);
1231 /* Modem wants us to STFU */
1232 gsm->constipated = 1;
1233 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0);
1236 /* Out of band modem line change indicator for a DLCI */
1237 gsm_control_modem(gsm, data, clen);
1240 /* Out of band error reception for a DLCI */
1241 gsm_control_rls(gsm, data, clen);
1244 /* Modem wishes to enter power saving state */
1245 gsm_control_reply(gsm, CMD_PSC, NULL, 0);
1247 /* Optional unsupported commands */
1248 case CMD_PN: /* Parameter negotiation */
1249 case CMD_RPN: /* Remote port negotiation */
1250 case CMD_SNC: /* Service negotiation command */
1252 /* Reply to bad commands with an NSC */
1254 gsm_control_reply(gsm, CMD_NSC, buf, 1);
1260 * gsm_control_response - process a response to our control
1262 * @command: the command (response) EA
1263 * @data: data beyond the command/length EA
1266 * Process a response to an outstanding command. We only allow a single
1267 * control message in flight so this is fairly easy. All the clean up
1268 * is done by the caller, we just update the fields, flag it as done
1272 static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
1275 struct gsm_control *ctrl;
1276 unsigned long flags;
1278 spin_lock_irqsave(&gsm->control_lock, flags);
1280 ctrl = gsm->pending_cmd;
1281 /* Does the reply match our command */
1283 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) {
1284 /* Our command was replied to, kill the retry timer */
1285 del_timer(&gsm->t2_timer);
1286 gsm->pending_cmd = NULL;
1287 /* Rejected by the other end */
1288 if (command == CMD_NSC)
1289 ctrl->error = -EOPNOTSUPP;
1291 wake_up(&gsm->event);
1293 spin_unlock_irqrestore(&gsm->control_lock, flags);
1297 * gsm_control_transmit - send control packet
1299 * @ctrl: frame to send
1301 * Send out a pending control command (called under control lock)
1304 static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl)
1306 struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, gsm->ftype);
1309 msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */
1310 memcpy(msg->data + 1, ctrl->data, ctrl->len);
1311 gsm_data_queue(gsm->dlci[0], msg);
1315 * gsm_control_retransmit - retransmit a control frame
1316 * @data: pointer to our gsm object
1318 * Called off the T2 timer expiry in order to retransmit control frames
1319 * that have been lost in the system somewhere. The control_lock protects
1320 * us from colliding with another sender or a receive completion event.
1321 * In that situation the timer may still occur in a small window but
1322 * gsm->pending_cmd will be NULL and we just let the timer expire.
1325 static void gsm_control_retransmit(unsigned long data)
1327 struct gsm_mux *gsm = (struct gsm_mux *)data;
1328 struct gsm_control *ctrl;
1329 unsigned long flags;
1330 spin_lock_irqsave(&gsm->control_lock, flags);
1331 ctrl = gsm->pending_cmd;
1334 if (gsm->cretries == 0) {
1335 gsm->pending_cmd = NULL;
1336 ctrl->error = -ETIMEDOUT;
1338 spin_unlock_irqrestore(&gsm->control_lock, flags);
1339 wake_up(&gsm->event);
1342 gsm_control_transmit(gsm, ctrl);
1343 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1345 spin_unlock_irqrestore(&gsm->control_lock, flags);
1349 * gsm_control_send - send a control frame on DLCI 0
1350 * @gsm: the GSM channel
1351 * @command: command to send including CR bit
1352 * @data: bytes of data (must be kmalloced)
1353 * @len: length of the block to send
1355 * Queue and dispatch a control command. Only one command can be
1356 * active at a time. In theory more can be outstanding but the matching
1357 * gets really complicated so for now stick to one outstanding.
1360 static struct gsm_control *gsm_control_send(struct gsm_mux *gsm,
1361 unsigned int command, u8 *data, int clen)
1363 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control),
1365 unsigned long flags;
1369 wait_event(gsm->event, gsm->pending_cmd == NULL);
1370 spin_lock_irqsave(&gsm->control_lock, flags);
1371 if (gsm->pending_cmd != NULL) {
1372 spin_unlock_irqrestore(&gsm->control_lock, flags);
1375 ctrl->cmd = command;
1378 gsm->pending_cmd = ctrl;
1379 gsm->cretries = gsm->n2;
1380 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1381 gsm_control_transmit(gsm, ctrl);
1382 spin_unlock_irqrestore(&gsm->control_lock, flags);
1387 * gsm_control_wait - wait for a control to finish
1389 * @control: control we are waiting on
1391 * Waits for the control to complete or time out. Frees any used
1392 * resources and returns 0 for success, or an error if the remote
1393 * rejected or ignored the request.
1396 static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
1399 wait_event(gsm->event, control->done == 1);
1400 err = control->error;
1407 * DLCI level handling: Needs krefs
1411 * State transitions and timers
1415 * gsm_dlci_close - a DLCI has closed
1416 * @dlci: DLCI that closed
1418 * Perform processing when moving a DLCI into closed state. If there
1419 * is an attached tty this is hung up
1422 static void gsm_dlci_close(struct gsm_dlci *dlci)
1424 del_timer(&dlci->t1);
1426 pr_debug("DLCI %d goes closed.\n", dlci->addr);
1427 dlci->state = DLCI_CLOSED;
1428 if (dlci->addr != 0) {
1429 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1434 kfifo_reset(dlci->fifo);
1436 dlci->gsm->dead = 1;
1437 wake_up(&dlci->gsm->event);
1438 /* A DLCI 0 close is a MUX termination so we need to kick that
1439 back to userspace somehow */
1443 * gsm_dlci_open - a DLCI has opened
1444 * @dlci: DLCI that opened
1446 * Perform processing when moving a DLCI into open state.
1449 static void gsm_dlci_open(struct gsm_dlci *dlci)
1451 /* Note that SABM UA .. SABM UA first UA lost can mean that we go
1453 del_timer(&dlci->t1);
1454 /* This will let a tty open continue */
1455 dlci->state = DLCI_OPEN;
1457 pr_debug("DLCI %d goes open.\n", dlci->addr);
1458 wake_up(&dlci->gsm->event);
1462 * gsm_dlci_t1 - T1 timer expiry
1463 * @dlci: DLCI that opened
1465 * The T1 timer handles retransmits of control frames (essentially of
1466 * SABM and DISC). We resend the command until the retry count runs out
1467 * in which case an opening port goes back to closed and a closing port
1468 * is simply put into closed state (any further frames from the other
1469 * end will get a DM response)
1472 static void gsm_dlci_t1(unsigned long data)
1474 struct gsm_dlci *dlci = (struct gsm_dlci *)data;
1475 struct gsm_mux *gsm = dlci->gsm;
1477 switch (dlci->state) {
1480 if (dlci->retries) {
1481 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1482 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1484 gsm_dlci_close(dlci);
1488 if (dlci->retries) {
1489 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1490 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1492 gsm_dlci_close(dlci);
1498 * gsm_dlci_begin_open - start channel open procedure
1499 * @dlci: DLCI to open
1501 * Commence opening a DLCI from the Linux side. We issue SABM messages
1502 * to the modem which should then reply with a UA, at which point we
1503 * will move into open state. Opening is done asynchronously with retry
1504 * running off timers and the responses.
1507 static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
1509 struct gsm_mux *gsm = dlci->gsm;
1510 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING)
1512 dlci->retries = gsm->n2;
1513 dlci->state = DLCI_OPENING;
1514 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1515 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1519 * gsm_dlci_begin_close - start channel open procedure
1520 * @dlci: DLCI to open
1522 * Commence closing a DLCI from the Linux side. We issue DISC messages
1523 * to the modem which should then reply with a UA, at which point we
1524 * will move into closed state. Closing is done asynchronously with retry
1525 * off timers. We may also receive a DM reply from the other end which
1526 * indicates the channel was already closed.
1529 static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
1531 struct gsm_mux *gsm = dlci->gsm;
1532 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
1534 dlci->retries = gsm->n2;
1535 dlci->state = DLCI_CLOSING;
1536 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1537 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1541 * gsm_dlci_data - data arrived
1543 * @data: block of bytes received
1544 * @len: length of received block
1546 * A UI or UIH frame has arrived which contains data for a channel
1547 * other than the control channel. If the relevant virtual tty is
1548 * open we shovel the bits down it, if not we drop them.
1551 static void gsm_dlci_data(struct gsm_dlci *dlci, u8 *data, int clen)
1554 struct tty_port *port = &dlci->port;
1555 struct tty_struct *tty = tty_port_tty_get(port);
1556 unsigned int modem = 0;
1560 pr_debug("%d bytes for tty %p\n", len, tty);
1562 switch (dlci->adaption) {
1563 /* Unsupported types */
1564 /* Packetised interruptible data */
1567 /* Packetised uininterruptible voice/data */
1570 /* Asynchronous serial with line state in each frame */
1572 while (gsm_read_ea(&modem, *data++) == 0) {
1577 gsm_process_modem(tty, dlci, modem, clen);
1578 /* Line state will go via DLCI 0 controls only */
1581 tty_insert_flip_string(port, data, len);
1582 tty_flip_buffer_push(tty);
1589 * gsm_dlci_control - data arrived on control channel
1591 * @data: block of bytes received
1592 * @len: length of received block
1594 * A UI or UIH frame has arrived which contains data for DLCI 0 the
1595 * control channel. This should contain a command EA followed by
1596 * control data bytes. The command EA contains a command/response bit
1597 * and we divide up the work accordingly.
1600 static void gsm_dlci_command(struct gsm_dlci *dlci, u8 *data, int len)
1602 /* See what command is involved */
1603 unsigned int command = 0;
1605 if (gsm_read_ea(&command, *data++) == 1) {
1608 /* FIXME: this is properly an EA */
1610 /* Malformed command ? */
1614 gsm_control_message(dlci->gsm, command,
1617 gsm_control_response(dlci->gsm, command,
1625 * Allocate/Free DLCI channels
1629 * gsm_dlci_alloc - allocate a DLCI
1631 * @addr: address of the DLCI
1633 * Allocate and install a new DLCI object into the GSM mux.
1635 * FIXME: review locking races
1638 static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
1640 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC);
1643 spin_lock_init(&dlci->lock);
1644 mutex_init(&dlci->mutex);
1645 dlci->fifo = &dlci->_fifo;
1646 if (kfifo_alloc(&dlci->_fifo, 4096, GFP_KERNEL) < 0) {
1651 skb_queue_head_init(&dlci->skb_list);
1652 init_timer(&dlci->t1);
1653 dlci->t1.function = gsm_dlci_t1;
1654 dlci->t1.data = (unsigned long)dlci;
1655 tty_port_init(&dlci->port);
1656 dlci->port.ops = &gsm_port_ops;
1659 dlci->adaption = gsm->adaption;
1660 dlci->state = DLCI_CLOSED;
1662 dlci->data = gsm_dlci_data;
1664 dlci->data = gsm_dlci_command;
1665 gsm->dlci[addr] = dlci;
1670 * gsm_dlci_free - free DLCI
1671 * @dlci: DLCI to free
1677 static void gsm_dlci_free(struct tty_port *port)
1679 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
1681 del_timer_sync(&dlci->t1);
1682 dlci->gsm->dlci[dlci->addr] = NULL;
1683 kfifo_free(dlci->fifo);
1684 while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
1685 dev_kfree_skb(dlci->skb);
1689 static inline void dlci_get(struct gsm_dlci *dlci)
1691 tty_port_get(&dlci->port);
1694 static inline void dlci_put(struct gsm_dlci *dlci)
1696 tty_port_put(&dlci->port);
1700 * gsm_dlci_release - release DLCI
1701 * @dlci: DLCI to destroy
1703 * Release a DLCI. Actual free is deferred until either
1704 * mux is closed or tty is closed - whichever is last.
1708 static void gsm_dlci_release(struct gsm_dlci *dlci)
1710 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1719 * LAPBish link layer logic
1723 * gsm_queue - a GSM frame is ready to process
1724 * @gsm: pointer to our gsm mux
1726 * At this point in time a frame has arrived and been demangled from
1727 * the line encoding. All the differences between the encodings have
1728 * been handled below us and the frame is unpacked into the structures.
1729 * The fcs holds the header FCS but any data FCS must be added here.
1732 static void gsm_queue(struct gsm_mux *gsm)
1734 struct gsm_dlci *dlci;
1737 /* We have to sneak a look at the packet body to do the FCS.
1738 A somewhat layering violation in the spec */
1740 if ((gsm->control & ~PF) == UI)
1741 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len);
1742 if (gsm->encoding == 0){
1743 /* WARNING: gsm->received_fcs is used for gsm->encoding = 0 only.
1744 In this case it contain the last piece of data
1745 required to generate final CRC */
1746 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs);
1748 if (gsm->fcs != GOOD_FCS) {
1751 pr_debug("BAD FCS %02x\n", gsm->fcs);
1754 address = gsm->address >> 1;
1755 if (address >= NUM_DLCI)
1758 cr = gsm->address & 1; /* C/R bit */
1760 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
1762 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */
1763 dlci = gsm->dlci[address];
1765 switch (gsm->control) {
1770 dlci = gsm_dlci_alloc(gsm, address);
1774 gsm_response(gsm, address, DM);
1776 gsm_response(gsm, address, UA);
1777 gsm_dlci_open(dlci);
1783 if (dlci == NULL || dlci->state == DLCI_CLOSED) {
1784 gsm_response(gsm, address, DM);
1787 /* Real close complete */
1788 gsm_response(gsm, address, UA);
1789 gsm_dlci_close(dlci);
1793 if (cr == 0 || dlci == NULL)
1795 switch (dlci->state) {
1797 gsm_dlci_close(dlci);
1800 gsm_dlci_open(dlci);
1804 case DM: /* DM can be valid unsolicited */
1810 gsm_dlci_close(dlci);
1820 if (dlci == NULL || dlci->state != DLCI_OPEN) {
1821 gsm_command(gsm, address, DM|PF);
1824 dlci->data(dlci, gsm->buf, gsm->len);
1837 * gsm0_receive - perform processing for non-transparency
1838 * @gsm: gsm data for this ldisc instance
1841 * Receive bytes in gsm mode 0
1844 static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
1848 switch (gsm->state) {
1849 case GSM_SEARCH: /* SOF marker */
1850 if (c == GSM0_SOF) {
1851 gsm->state = GSM_ADDRESS;
1854 gsm->fcs = INIT_FCS;
1857 case GSM_ADDRESS: /* Address EA */
1858 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1859 if (gsm_read_ea(&gsm->address, c))
1860 gsm->state = GSM_CONTROL;
1862 case GSM_CONTROL: /* Control Byte */
1863 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1865 gsm->state = GSM_LEN0;
1867 case GSM_LEN0: /* Length EA */
1868 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1869 if (gsm_read_ea(&gsm->len, c)) {
1870 if (gsm->len > gsm->mru) {
1872 gsm->state = GSM_SEARCH;
1877 gsm->state = GSM_FCS;
1879 gsm->state = GSM_DATA;
1882 gsm->state = GSM_LEN1;
1885 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1887 gsm->len |= len << 7;
1888 if (gsm->len > gsm->mru) {
1890 gsm->state = GSM_SEARCH;
1895 gsm->state = GSM_FCS;
1897 gsm->state = GSM_DATA;
1899 case GSM_DATA: /* Data */
1900 gsm->buf[gsm->count++] = c;
1901 if (gsm->count == gsm->len)
1902 gsm->state = GSM_FCS;
1904 case GSM_FCS: /* FCS follows the packet */
1905 gsm->received_fcs = c;
1907 gsm->state = GSM_SSOF;
1910 if (c == GSM0_SOF) {
1911 gsm->state = GSM_SEARCH;
1919 * gsm1_receive - perform processing for non-transparency
1920 * @gsm: gsm data for this ldisc instance
1923 * Receive bytes in mode 1 (Advanced option)
1926 static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
1928 if (c == GSM1_SOF) {
1929 /* EOF is only valid in frame if we have got to the data state
1930 and received at least one byte (the FCS) */
1931 if (gsm->state == GSM_DATA && gsm->count) {
1932 /* Extract the FCS */
1934 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
1935 gsm->len = gsm->count;
1937 gsm->state = GSM_START;
1940 /* Any partial frame was a runt so go back to start */
1941 if (gsm->state != GSM_START) {
1943 gsm->state = GSM_START;
1945 /* A SOF in GSM_START means we are still reading idling or
1950 if (c == GSM1_ESCAPE) {
1955 /* Only an unescaped SOF gets us out of GSM search */
1956 if (gsm->state == GSM_SEARCH)
1960 c ^= GSM1_ESCAPE_BITS;
1963 switch (gsm->state) {
1964 case GSM_START: /* First byte after SOF */
1966 gsm->state = GSM_ADDRESS;
1967 gsm->fcs = INIT_FCS;
1969 case GSM_ADDRESS: /* Address continuation */
1970 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1971 if (gsm_read_ea(&gsm->address, c))
1972 gsm->state = GSM_CONTROL;
1974 case GSM_CONTROL: /* Control Byte */
1975 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1978 gsm->state = GSM_DATA;
1980 case GSM_DATA: /* Data */
1981 if (gsm->count > gsm->mru) { /* Allow one for the FCS */
1982 gsm->state = GSM_OVERRUN;
1985 gsm->buf[gsm->count++] = c;
1987 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */
1993 * gsm_error - handle tty error
1995 * @data: byte received (may be invalid)
1996 * @flag: error received
1998 * Handle an error in the receipt of data for a frame. Currently we just
1999 * go back to hunting for a SOF.
2001 * FIXME: better diagnostics ?
2004 static void gsm_error(struct gsm_mux *gsm,
2005 unsigned char data, unsigned char flag)
2007 gsm->state = GSM_SEARCH;
2012 * gsm_cleanup_mux - generic GSM protocol cleanup
2015 * Clean up the bits of the mux which are the same for all framing
2016 * protocols. Remove the mux from the mux table, stop all the timers
2017 * and then shut down each device hanging up the channels as we go.
2020 void gsm_cleanup_mux(struct gsm_mux *gsm)
2023 struct gsm_dlci *dlci = gsm->dlci[0];
2024 struct gsm_msg *txq, *ntxq;
2025 struct gsm_control *gc;
2029 spin_lock(&gsm_mux_lock);
2030 for (i = 0; i < MAX_MUX; i++) {
2031 if (gsm_mux[i] == gsm) {
2036 spin_unlock(&gsm_mux_lock);
2037 WARN_ON(i == MAX_MUX);
2039 /* In theory disconnecting DLCI 0 is sufficient but for some
2040 modems this is apparently not the case. */
2042 gc = gsm_control_send(gsm, CMD_CLD, NULL, 0);
2044 gsm_control_wait(gsm, gc);
2046 del_timer_sync(&gsm->t2_timer);
2047 /* Now we are sure T2 has stopped */
2050 gsm_dlci_begin_close(dlci);
2051 wait_event_interruptible(gsm->event,
2052 dlci->state == DLCI_CLOSED);
2054 /* Free up any link layer users */
2055 for (i = 0; i < NUM_DLCI; i++)
2057 gsm_dlci_release(gsm->dlci[i]);
2058 /* Now wipe the queues */
2059 list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list)
2061 INIT_LIST_HEAD(&gsm->tx_list);
2063 EXPORT_SYMBOL_GPL(gsm_cleanup_mux);
2066 * gsm_activate_mux - generic GSM setup
2069 * Set up the bits of the mux which are the same for all framing
2070 * protocols. Add the mux to the mux table so it can be opened and
2071 * finally kick off connecting to DLCI 0 on the modem.
2074 int gsm_activate_mux(struct gsm_mux *gsm)
2076 struct gsm_dlci *dlci;
2079 init_timer(&gsm->t2_timer);
2080 gsm->t2_timer.function = gsm_control_retransmit;
2081 gsm->t2_timer.data = (unsigned long)gsm;
2082 init_waitqueue_head(&gsm->event);
2083 spin_lock_init(&gsm->control_lock);
2084 spin_lock_init(&gsm->tx_lock);
2086 if (gsm->encoding == 0)
2087 gsm->receive = gsm0_receive;
2089 gsm->receive = gsm1_receive;
2090 gsm->error = gsm_error;
2092 spin_lock(&gsm_mux_lock);
2093 for (i = 0; i < MAX_MUX; i++) {
2094 if (gsm_mux[i] == NULL) {
2100 spin_unlock(&gsm_mux_lock);
2104 dlci = gsm_dlci_alloc(gsm, 0);
2107 gsm->dead = 0; /* Tty opens are now permissible */
2110 EXPORT_SYMBOL_GPL(gsm_activate_mux);
2113 * gsm_free_mux - free up a mux
2116 * Dispose of allocated resources for a dead mux
2118 void gsm_free_mux(struct gsm_mux *gsm)
2120 kfree(gsm->txframe);
2124 EXPORT_SYMBOL_GPL(gsm_free_mux);
2127 * gsm_free_muxr - free up a mux
2130 * Dispose of allocated resources for a dead mux
2132 static void gsm_free_muxr(struct kref *ref)
2134 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref);
2138 static inline void mux_get(struct gsm_mux *gsm)
2140 kref_get(&gsm->ref);
2143 static inline void mux_put(struct gsm_mux *gsm)
2145 kref_put(&gsm->ref, gsm_free_muxr);
2149 * gsm_alloc_mux - allocate a mux
2151 * Creates a new mux ready for activation.
2154 struct gsm_mux *gsm_alloc_mux(void)
2156 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
2159 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL);
2160 if (gsm->buf == NULL) {
2164 gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL);
2165 if (gsm->txframe == NULL) {
2170 spin_lock_init(&gsm->lock);
2171 kref_init(&gsm->ref);
2172 INIT_LIST_HEAD(&gsm->tx_list);
2180 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
2182 gsm->dead = 1; /* Avoid early tty opens */
2186 EXPORT_SYMBOL_GPL(gsm_alloc_mux);
2189 * gsmld_output - write to link
2191 * @data: bytes to output
2194 * Write a block of data from the GSM mux to the data channel. This
2195 * will eventually be serialized from above but at the moment isn't.
2198 static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
2200 if (tty_write_room(gsm->tty) < len) {
2201 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
2205 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET,
2207 gsm->tty->ops->write(gsm->tty, data, len);
2212 * gsmld_attach_gsm - mode set up
2213 * @tty: our tty structure
2216 * Set up the MUX for basic mode and commence connecting to the
2217 * modem. Currently called from the line discipline set up but
2218 * will need moving to an ioctl path.
2221 static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2224 int base = gsm->num << 6; /* Base for this MUX */
2226 gsm->tty = tty_kref_get(tty);
2227 gsm->output = gsmld_output;
2228 ret = gsm_activate_mux(gsm);
2230 tty_kref_put(gsm->tty);
2232 /* Don't register device 0 - this is the control channel and not
2233 a usable tty interface */
2234 for (i = 1; i < NUM_DLCI; i++)
2235 tty_register_device(gsm_tty_driver, base + i, NULL);
2242 * gsmld_detach_gsm - stop doing 0710 mux
2243 * @tty: tty attached to the mux
2246 * Shutdown and then clean up the resources used by the line discipline
2249 static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2252 int base = gsm->num << 6; /* Base for this MUX */
2254 WARN_ON(tty != gsm->tty);
2255 for (i = 1; i < NUM_DLCI; i++)
2256 tty_unregister_device(gsm_tty_driver, base + i);
2257 gsm_cleanup_mux(gsm);
2258 tty_kref_put(gsm->tty);
2262 static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
2263 char *fp, int count)
2265 struct gsm_mux *gsm = tty->disc_data;
2266 const unsigned char *dp;
2273 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET,
2276 for (i = count, dp = cp, f = fp; i; i--, dp++) {
2280 gsm->receive(gsm, *dp);
2286 gsm->error(gsm, *dp, flags);
2289 WARN_ONCE(1, "%s: unknown flag %d\n",
2290 tty_name(tty, buf), flags);
2294 /* FASYNC if needed ? */
2295 /* If clogged call tty_throttle(tty); */
2299 * gsmld_chars_in_buffer - report available bytes
2302 * Report the number of characters buffered to be delivered to user
2303 * at this instant in time.
2308 static ssize_t gsmld_chars_in_buffer(struct tty_struct *tty)
2314 * gsmld_flush_buffer - clean input queue
2315 * @tty: terminal device
2317 * Flush the input buffer. Called when the line discipline is
2318 * being closed, when the tty layer wants the buffer flushed (eg
2322 static void gsmld_flush_buffer(struct tty_struct *tty)
2327 * gsmld_close - close the ldisc for this tty
2330 * Called from the terminal layer when this line discipline is
2331 * being shut down, either because of a close or becsuse of a
2332 * discipline change. The function will not be called while other
2333 * ldisc methods are in progress.
2336 static void gsmld_close(struct tty_struct *tty)
2338 struct gsm_mux *gsm = tty->disc_data;
2340 gsmld_detach_gsm(tty, gsm);
2342 gsmld_flush_buffer(tty);
2343 /* Do other clean up here */
2348 * gsmld_open - open an ldisc
2349 * @tty: terminal to open
2351 * Called when this line discipline is being attached to the
2352 * terminal device. Can sleep. Called serialized so that no
2353 * other events will occur in parallel. No further open will occur
2357 static int gsmld_open(struct tty_struct *tty)
2359 struct gsm_mux *gsm;
2361 if (tty->ops->write == NULL)
2364 /* Attach our ldisc data */
2365 gsm = gsm_alloc_mux();
2369 tty->disc_data = gsm;
2370 tty->receive_room = 65536;
2372 /* Attach the initial passive connection */
2374 return gsmld_attach_gsm(tty, gsm);
2378 * gsmld_write_wakeup - asynchronous I/O notifier
2381 * Required for the ptys, serial driver etc. since processes
2382 * that attach themselves to the master and rely on ASYNC
2383 * IO must be woken up
2386 static void gsmld_write_wakeup(struct tty_struct *tty)
2388 struct gsm_mux *gsm = tty->disc_data;
2389 unsigned long flags;
2392 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2393 spin_lock_irqsave(&gsm->tx_lock, flags);
2395 if (gsm->tx_bytes < TX_THRESH_LO) {
2396 gsm_dlci_data_sweep(gsm);
2398 spin_unlock_irqrestore(&gsm->tx_lock, flags);
2402 * gsmld_read - read function for tty
2404 * @file: file object
2405 * @buf: userspace buffer pointer
2408 * Perform reads for the line discipline. We are guaranteed that the
2409 * line discipline will not be closed under us but we may get multiple
2410 * parallel readers and must handle this ourselves. We may also get
2411 * a hangup. Always called in user context, may sleep.
2413 * This code must be sure never to sleep through a hangup.
2416 static ssize_t gsmld_read(struct tty_struct *tty, struct file *file,
2417 unsigned char __user *buf, size_t nr)
2423 * gsmld_write - write function for tty
2425 * @file: file object
2426 * @buf: userspace buffer pointer
2429 * Called when the owner of the device wants to send a frame
2430 * itself (or some other control data). The data is transferred
2431 * as-is and must be properly framed and checksummed as appropriate
2432 * by userspace. Frames are either sent whole or not at all as this
2433 * avoids pain user side.
2436 static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
2437 const unsigned char *buf, size_t nr)
2439 int space = tty_write_room(tty);
2441 return tty->ops->write(tty, buf, nr);
2442 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2447 * gsmld_poll - poll method for N_GSM0710
2448 * @tty: terminal device
2449 * @file: file accessing it
2452 * Called when the line discipline is asked to poll() for data or
2453 * for special events. This code is not serialized with respect to
2454 * other events save open/close.
2456 * This code must be sure never to sleep through a hangup.
2457 * Called without the kernel lock held - fine
2460 static unsigned int gsmld_poll(struct tty_struct *tty, struct file *file,
2463 unsigned int mask = 0;
2464 struct gsm_mux *gsm = tty->disc_data;
2466 poll_wait(file, &tty->read_wait, wait);
2467 poll_wait(file, &tty->write_wait, wait);
2468 if (tty_hung_up_p(file))
2470 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
2471 mask |= POLLOUT | POLLWRNORM;
2477 static int gsmld_config(struct tty_struct *tty, struct gsm_mux *gsm,
2478 struct gsm_config *c)
2481 int need_restart = 0;
2483 /* Stuff we don't support yet - UI or I frame transport, windowing */
2484 if ((c->adaption != 1 && c->adaption != 2) || c->k)
2486 /* Check the MRU/MTU range looks sane */
2487 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8)
2491 if (c->encapsulation > 1) /* Basic, advanced, no I */
2493 if (c->initiator > 1)
2495 if (c->i == 0 || c->i > 2) /* UIH and UI only */
2498 * See what is needed for reconfiguration
2502 if (c->t1 != 0 && c->t1 != gsm->t1)
2504 if (c->t2 != 0 && c->t2 != gsm->t2)
2506 if (c->encapsulation != gsm->encoding)
2508 if (c->adaption != gsm->adaption)
2511 if (c->initiator != gsm->initiator)
2513 if (c->mru != gsm->mru)
2515 if (c->mtu != gsm->mtu)
2519 * Close down what is needed, restart and initiate the new
2523 if (need_close || need_restart) {
2524 gsm_dlci_begin_close(gsm->dlci[0]);
2525 /* This will timeout if the link is down due to N2 expiring */
2526 wait_event_interruptible(gsm->event,
2527 gsm->dlci[0]->state == DLCI_CLOSED);
2528 if (signal_pending(current))
2532 gsm_cleanup_mux(gsm);
2534 gsm->initiator = c->initiator;
2537 gsm->encoding = c->encapsulation;
2538 gsm->adaption = c->adaption;
2551 /* FIXME: We need to separate activation/deactivation from adding
2552 and removing from the mux array */
2554 gsm_activate_mux(gsm);
2555 if (gsm->initiator && need_close)
2556 gsm_dlci_begin_open(gsm->dlci[0]);
2560 static int gsmld_ioctl(struct tty_struct *tty, struct file *file,
2561 unsigned int cmd, unsigned long arg)
2563 struct gsm_config c;
2564 struct gsm_mux *gsm = tty->disc_data;
2567 case GSMIOC_GETCONF:
2568 memset(&c, 0, sizeof(c));
2569 c.adaption = gsm->adaption;
2570 c.encapsulation = gsm->encoding;
2571 c.initiator = gsm->initiator;
2574 c.t3 = 0; /* Not supported */
2576 if (gsm->ftype == UIH)
2580 pr_debug("Ftype %d i %d\n", gsm->ftype, c.i);
2584 if (copy_to_user((void *)arg, &c, sizeof(c)))
2587 case GSMIOC_SETCONF:
2588 if (copy_from_user(&c, (void *)arg, sizeof(c)))
2590 return gsmld_config(tty, gsm, &c);
2592 return n_tty_ioctl_helper(tty, file, cmd, arg);
2601 static int gsm_mux_net_open(struct net_device *net)
2603 pr_debug("%s called\n", __func__);
2604 netif_start_queue(net);
2608 static int gsm_mux_net_close(struct net_device *net)
2610 netif_stop_queue(net);
2614 static struct net_device_stats *gsm_mux_net_get_stats(struct net_device *net)
2616 return &((struct gsm_mux_net *)netdev_priv(net))->stats;
2618 static void dlci_net_free(struct gsm_dlci *dlci)
2624 dlci->adaption = dlci->prev_adaption;
2625 dlci->data = dlci->prev_data;
2626 free_netdev(dlci->net);
2629 static void net_free(struct kref *ref)
2631 struct gsm_mux_net *mux_net;
2632 struct gsm_dlci *dlci;
2634 mux_net = container_of(ref, struct gsm_mux_net, ref);
2635 dlci = mux_net->dlci;
2638 unregister_netdev(dlci->net);
2639 dlci_net_free(dlci);
2643 static inline void muxnet_get(struct gsm_mux_net *mux_net)
2645 kref_get(&mux_net->ref);
2648 static inline void muxnet_put(struct gsm_mux_net *mux_net)
2650 kref_put(&mux_net->ref, net_free);
2653 static int gsm_mux_net_start_xmit(struct sk_buff *skb,
2654 struct net_device *net)
2656 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
2657 struct gsm_dlci *dlci = mux_net->dlci;
2658 muxnet_get(mux_net);
2660 skb_queue_head(&dlci->skb_list, skb);
2661 STATS(net).tx_packets++;
2662 STATS(net).tx_bytes += skb->len;
2663 gsm_dlci_data_kick(dlci);
2664 /* And tell the kernel when the last transmit started. */
2665 net->trans_start = jiffies;
2666 muxnet_put(mux_net);
2667 return NETDEV_TX_OK;
2670 /* called when a packet did not ack after watchdogtimeout */
2671 static void gsm_mux_net_tx_timeout(struct net_device *net)
2673 /* Tell syslog we are hosed. */
2674 dev_dbg(&net->dev, "Tx timed out.\n");
2676 /* Update statistics */
2677 STATS(net).tx_errors++;
2680 static void gsm_mux_rx_netchar(struct gsm_dlci *dlci,
2681 unsigned char *in_buf, int size)
2683 struct net_device *net = dlci->net;
2684 struct sk_buff *skb;
2685 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
2686 muxnet_get(mux_net);
2688 /* Allocate an sk_buff */
2689 skb = dev_alloc_skb(size + NET_IP_ALIGN);
2691 /* We got no receive buffer. */
2692 STATS(net).rx_dropped++;
2693 muxnet_put(mux_net);
2696 skb_reserve(skb, NET_IP_ALIGN);
2697 memcpy(skb_put(skb, size), in_buf, size);
2700 skb->protocol = __constant_htons(ETH_P_IP);
2702 /* Ship it off to the kernel */
2705 /* update out statistics */
2706 STATS(net).rx_packets++;
2707 STATS(net).rx_bytes += size;
2708 muxnet_put(mux_net);
2712 int gsm_change_mtu(struct net_device *net, int new_mtu)
2714 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
2715 if ((new_mtu < 8) || (new_mtu > mux_net->dlci->gsm->mtu))
2721 static void gsm_mux_net_init(struct net_device *net)
2723 static const struct net_device_ops gsm_netdev_ops = {
2724 .ndo_open = gsm_mux_net_open,
2725 .ndo_stop = gsm_mux_net_close,
2726 .ndo_start_xmit = gsm_mux_net_start_xmit,
2727 .ndo_tx_timeout = gsm_mux_net_tx_timeout,
2728 .ndo_get_stats = gsm_mux_net_get_stats,
2729 .ndo_change_mtu = gsm_change_mtu,
2732 net->netdev_ops = &gsm_netdev_ops;
2734 /* fill in the other fields */
2735 net->watchdog_timeo = GSM_NET_TX_TIMEOUT;
2736 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
2737 net->type = ARPHRD_NONE;
2738 net->tx_queue_len = 10;
2742 /* caller holds the dlci mutex */
2743 static void gsm_destroy_network(struct gsm_dlci *dlci)
2745 struct gsm_mux_net *mux_net;
2747 pr_debug("destroy network interface");
2750 mux_net = (struct gsm_mux_net *)netdev_priv(dlci->net);
2751 muxnet_put(mux_net);
2755 /* caller holds the dlci mutex */
2756 static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
2760 struct net_device *net;
2761 struct gsm_mux_net *mux_net;
2763 if (!capable(CAP_NET_ADMIN))
2766 /* Already in a non tty mode */
2767 if (dlci->adaption > 2)
2770 if (nc->protocol != htons(ETH_P_IP))
2771 return -EPROTONOSUPPORT;
2773 if (nc->adaption != 3 && nc->adaption != 4)
2774 return -EPROTONOSUPPORT;
2776 pr_debug("create network interface");
2779 if (nc->if_name[0] != '\0')
2780 netname = nc->if_name;
2781 net = alloc_netdev(sizeof(struct gsm_mux_net),
2785 pr_err("alloc_netdev failed");
2788 net->mtu = dlci->gsm->mtu;
2789 mux_net = (struct gsm_mux_net *)netdev_priv(net);
2790 mux_net->dlci = dlci;
2791 kref_init(&mux_net->ref);
2792 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */
2794 /* reconfigure dlci for network */
2795 dlci->prev_adaption = dlci->adaption;
2796 dlci->prev_data = dlci->data;
2797 dlci->adaption = nc->adaption;
2798 dlci->data = gsm_mux_rx_netchar;
2801 pr_debug("register netdev");
2802 retval = register_netdev(net);
2804 pr_err("network register fail %d\n", retval);
2805 dlci_net_free(dlci);
2808 return net->ifindex; /* return network index */
2811 /* Line discipline for real tty */
2812 struct tty_ldisc_ops tty_ldisc_packet = {
2813 .owner = THIS_MODULE,
2814 .magic = TTY_LDISC_MAGIC,
2817 .close = gsmld_close,
2818 .flush_buffer = gsmld_flush_buffer,
2819 .chars_in_buffer = gsmld_chars_in_buffer,
2821 .write = gsmld_write,
2822 .ioctl = gsmld_ioctl,
2824 .receive_buf = gsmld_receive_buf,
2825 .write_wakeup = gsmld_write_wakeup
2834 static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk)
2837 struct gsm_control *ctrl;
2843 modembits[0] = len << 1 | EA; /* Data bytes */
2844 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */
2845 modembits[2] = gsm_encode_modem(dlci) << 1 | EA;
2847 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */
2848 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1);
2851 return gsm_control_wait(dlci->gsm, ctrl);
2854 static int gsm_carrier_raised(struct tty_port *port)
2856 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2857 /* Not yet open so no carrier info */
2858 if (dlci->state != DLCI_OPEN)
2862 return dlci->modem_rx & TIOCM_CD;
2865 static void gsm_dtr_rts(struct tty_port *port, int onoff)
2867 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2868 unsigned int modem_tx = dlci->modem_tx;
2870 modem_tx |= TIOCM_DTR | TIOCM_RTS;
2872 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
2873 if (modem_tx != dlci->modem_tx) {
2874 dlci->modem_tx = modem_tx;
2875 gsmtty_modem_update(dlci, 0);
2879 static const struct tty_port_operations gsm_port_ops = {
2880 .carrier_raised = gsm_carrier_raised,
2881 .dtr_rts = gsm_dtr_rts,
2882 .destruct = gsm_dlci_free,
2885 static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty)
2887 struct gsm_mux *gsm;
2888 struct gsm_dlci *dlci;
2889 unsigned int line = tty->index;
2890 unsigned int mux = line >> 6;
2898 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
2899 if (gsm_mux[mux] == NULL)
2901 if (line == 0 || line > 61) /* 62/63 reserved */
2906 /* If DLCI 0 is not yet fully open return an error. This is ok from a locking
2907 perspective as we don't have to worry about this if DLCI0 is lost */
2908 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN)
2910 dlci = gsm->dlci[line];
2913 dlci = gsm_dlci_alloc(gsm, line);
2917 ret = tty_port_install(&dlci->port, driver, tty);
2924 tty->driver_data = dlci;
2929 static int gsmtty_open(struct tty_struct *tty, struct file *filp)
2931 struct gsm_dlci *dlci = tty->driver_data;
2932 struct tty_port *port = &dlci->port;
2936 dlci_get(dlci->gsm->dlci[0]);
2938 tty_port_tty_set(port, tty);
2941 /* We could in theory open and close before we wait - eg if we get
2942 a DM straight back. This is ok as that will have caused a hangup */
2943 set_bit(ASYNCB_INITIALIZED, &port->flags);
2944 /* Start sending off SABM messages */
2945 gsm_dlci_begin_open(dlci);
2946 /* And wait for virtual carrier */
2947 return tty_port_block_til_ready(port, tty, filp);
2950 static void gsmtty_close(struct tty_struct *tty, struct file *filp)
2952 struct gsm_dlci *dlci = tty->driver_data;
2953 struct gsm_mux *gsm;
2957 mutex_lock(&dlci->mutex);
2958 gsm_destroy_network(dlci);
2959 mutex_unlock(&dlci->mutex);
2961 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
2963 gsm_dlci_begin_close(dlci);
2964 tty_port_close_end(&dlci->port, tty);
2965 tty_port_tty_set(&dlci->port, NULL);
2968 dlci_put(gsm->dlci[0]);
2972 static void gsmtty_hangup(struct tty_struct *tty)
2974 struct gsm_dlci *dlci = tty->driver_data;
2975 tty_port_hangup(&dlci->port);
2976 gsm_dlci_begin_close(dlci);
2979 static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf,
2982 struct gsm_dlci *dlci = tty->driver_data;
2983 /* Stuff the bytes into the fifo queue */
2984 int sent = kfifo_in_locked(dlci->fifo, buf, len, &dlci->lock);
2985 /* Need to kick the channel */
2986 gsm_dlci_data_kick(dlci);
2990 static int gsmtty_write_room(struct tty_struct *tty)
2992 struct gsm_dlci *dlci = tty->driver_data;
2993 return TX_SIZE - kfifo_len(dlci->fifo);
2996 static int gsmtty_chars_in_buffer(struct tty_struct *tty)
2998 struct gsm_dlci *dlci = tty->driver_data;
2999 return kfifo_len(dlci->fifo);
3002 static void gsmtty_flush_buffer(struct tty_struct *tty)
3004 struct gsm_dlci *dlci = tty->driver_data;
3005 /* Caution needed: If we implement reliable transport classes
3006 then the data being transmitted can't simply be junked once
3007 it has first hit the stack. Until then we can just blow it
3009 kfifo_reset(dlci->fifo);
3010 /* Need to unhook this DLCI from the transmit queue logic */
3013 static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
3015 /* The FIFO handles the queue so the kernel will do the right
3016 thing waiting on chars_in_buffer before calling us. No work
3020 static int gsmtty_tiocmget(struct tty_struct *tty)
3022 struct gsm_dlci *dlci = tty->driver_data;
3023 return dlci->modem_rx;
3026 static int gsmtty_tiocmset(struct tty_struct *tty,
3027 unsigned int set, unsigned int clear)
3029 struct gsm_dlci *dlci = tty->driver_data;
3030 unsigned int modem_tx = dlci->modem_tx;
3035 if (modem_tx != dlci->modem_tx) {
3036 dlci->modem_tx = modem_tx;
3037 return gsmtty_modem_update(dlci, 0);
3043 static int gsmtty_ioctl(struct tty_struct *tty,
3044 unsigned int cmd, unsigned long arg)
3046 struct gsm_dlci *dlci = tty->driver_data;
3047 struct gsm_netconfig nc;
3051 case GSMIOC_ENABLE_NET:
3052 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc)))
3054 nc.if_name[IFNAMSIZ-1] = '\0';
3055 /* return net interface index or error code */
3056 mutex_lock(&dlci->mutex);
3057 index = gsm_create_network(dlci, &nc);
3058 mutex_unlock(&dlci->mutex);
3059 if (copy_to_user((void __user *)arg, &nc, sizeof(nc)))
3062 case GSMIOC_DISABLE_NET:
3063 if (!capable(CAP_NET_ADMIN))
3065 mutex_lock(&dlci->mutex);
3066 gsm_destroy_network(dlci);
3067 mutex_unlock(&dlci->mutex);
3070 return -ENOIOCTLCMD;
3074 static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old)
3076 /* For the moment its fixed. In actual fact the speed information
3077 for the virtual channel can be propogated in both directions by
3078 the RPN control message. This however rapidly gets nasty as we
3079 then have to remap modem signals each way according to whether
3080 our virtual cable is null modem etc .. */
3081 tty_termios_copy_hw(&tty->termios, old);
3084 static void gsmtty_throttle(struct tty_struct *tty)
3086 struct gsm_dlci *dlci = tty->driver_data;
3087 if (tty->termios.c_cflag & CRTSCTS)
3088 dlci->modem_tx &= ~TIOCM_DTR;
3089 dlci->throttled = 1;
3090 /* Send an MSC with DTR cleared */
3091 gsmtty_modem_update(dlci, 0);
3094 static void gsmtty_unthrottle(struct tty_struct *tty)
3096 struct gsm_dlci *dlci = tty->driver_data;
3097 if (tty->termios.c_cflag & CRTSCTS)
3098 dlci->modem_tx |= TIOCM_DTR;
3099 dlci->throttled = 0;
3100 /* Send an MSC with DTR set */
3101 gsmtty_modem_update(dlci, 0);
3104 static int gsmtty_break_ctl(struct tty_struct *tty, int state)
3106 struct gsm_dlci *dlci = tty->driver_data;
3107 int encode = 0; /* Off */
3109 if (state == -1) /* "On indefinitely" - we can't encode this
3112 else if (state > 0) {
3113 encode = state / 200; /* mS to encoding */
3115 encode = 0x0F; /* Best effort */
3117 return gsmtty_modem_update(dlci, encode);
3121 /* Virtual ttys for the demux */
3122 static const struct tty_operations gsmtty_ops = {
3123 .install = gsmtty_install,
3124 .open = gsmtty_open,
3125 .close = gsmtty_close,
3126 .write = gsmtty_write,
3127 .write_room = gsmtty_write_room,
3128 .chars_in_buffer = gsmtty_chars_in_buffer,
3129 .flush_buffer = gsmtty_flush_buffer,
3130 .ioctl = gsmtty_ioctl,
3131 .throttle = gsmtty_throttle,
3132 .unthrottle = gsmtty_unthrottle,
3133 .set_termios = gsmtty_set_termios,
3134 .hangup = gsmtty_hangup,
3135 .wait_until_sent = gsmtty_wait_until_sent,
3136 .tiocmget = gsmtty_tiocmget,
3137 .tiocmset = gsmtty_tiocmset,
3138 .break_ctl = gsmtty_break_ctl,
3143 static int __init gsm_init(void)
3145 /* Fill in our line protocol discipline, and register it */
3146 int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet);
3148 pr_err("n_gsm: can't register line discipline (err = %d)\n",
3153 gsm_tty_driver = alloc_tty_driver(256);
3154 if (!gsm_tty_driver) {
3155 tty_unregister_ldisc(N_GSM0710);
3156 pr_err("gsm_init: tty allocation failed.\n");
3159 gsm_tty_driver->driver_name = "gsmtty";
3160 gsm_tty_driver->name = "gsmtty";
3161 gsm_tty_driver->major = 0; /* Dynamic */
3162 gsm_tty_driver->minor_start = 0;
3163 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
3164 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
3165 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV
3166 | TTY_DRIVER_HARDWARE_BREAK;
3167 gsm_tty_driver->init_termios = tty_std_termios;
3169 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
3170 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
3172 spin_lock_init(&gsm_mux_lock);
3174 if (tty_register_driver(gsm_tty_driver)) {
3175 put_tty_driver(gsm_tty_driver);
3176 tty_unregister_ldisc(N_GSM0710);
3177 pr_err("gsm_init: tty registration failed.\n");
3180 pr_debug("gsm_init: loaded as %d,%d.\n",
3181 gsm_tty_driver->major, gsm_tty_driver->minor_start);
3185 static void __exit gsm_exit(void)
3187 int status = tty_unregister_ldisc(N_GSM0710);
3189 pr_err("n_gsm: can't unregister line discipline (err = %d)\n",
3191 tty_unregister_driver(gsm_tty_driver);
3192 put_tty_driver(gsm_tty_driver);
3195 module_init(gsm_init);
3196 module_exit(gsm_exit);
3199 MODULE_LICENSE("GPL");
3200 MODULE_ALIAS_LDISC(N_GSM0710);