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 ?
25 * Improve the tx engine
26 * Resolve tx side locking by adding a queue_head and routing
27 * all control traffic via it
28 * General tidy/document
29 * Review the locking/move to refcounts more (mux now moved to an
30 * alloc/free model ready)
31 * Use newest tty open/close port helpers and install hooks
32 * What to do about power functions ?
33 * Termios setting and negotiation
34 * Do we need a 'which mux are you' ioctl to correlate mux and tty sets
38 #include <linux/types.h>
39 #include <linux/major.h>
40 #include <linux/errno.h>
41 #include <linux/signal.h>
42 #include <linux/fcntl.h>
43 #include <linux/sched.h>
44 #include <linux/interrupt.h>
45 #include <linux/tty.h>
46 #include <linux/ctype.h>
48 #include <linux/string.h>
49 #include <linux/slab.h>
50 #include <linux/poll.h>
51 #include <linux/bitops.h>
52 #include <linux/file.h>
53 #include <linux/uaccess.h>
54 #include <linux/module.h>
55 #include <linux/timer.h>
56 #include <linux/tty_flip.h>
57 #include <linux/tty_driver.h>
58 #include <linux/serial.h>
59 #include <linux/kfifo.h>
60 #include <linux/skbuff.h>
63 #include <linux/netdevice.h>
64 #include <linux/etherdevice.h>
65 #include <linux/gsmmux.h>
68 module_param(debug, int, 0600);
74 /* Use long timers for testing at low speed with debug on */
81 * Semi-arbitrary buffer size limits. 0710 is normally run with 32-64 byte
82 * limits so this is plenty
86 #define GSM_NET_TX_TIMEOUT (HZ*10)
89 * struct gsm_mux_net - network interface
90 * @struct gsm_dlci* dlci
91 * @struct net_device_stats stats;
93 * Created when net interface is initialized.
97 struct gsm_dlci *dlci;
98 struct net_device_stats stats;
101 #define STATS(net) (((struct gsm_mux_net *)netdev_priv(net))->stats)
104 * Each block of data we have queued to go out is in the form of
105 * a gsm_msg which holds everything we need in a link layer independent
110 struct gsm_msg *next;
111 u8 addr; /* DLCI address + flags */
112 u8 ctrl; /* Control byte + flags */
113 unsigned int len; /* Length of data block (can be zero) */
114 unsigned char *data; /* Points into buffer but not at the start */
115 unsigned char buffer[0];
119 * Each active data link has a gsm_dlci structure associated which ties
120 * the link layer to an optional tty (if the tty side is open). To avoid
121 * complexity right now these are only ever freed up when the mux is
124 * At the moment we don't free DLCI objects until the mux is torn down
125 * this avoid object life time issues but might be worth review later.
132 #define DLCI_CLOSED 0
133 #define DLCI_OPENING 1 /* Sending SABM not seen UA */
134 #define DLCI_OPEN 2 /* SABM/UA complete */
135 #define DLCI_CLOSING 3 /* Sending DISC not seen UA/DM */
136 struct kref ref; /* freed from port or mux close */
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 gsm_msg *tx_head; /* Pending data packets */
248 struct gsm_msg *tx_tail;
250 /* Control messages */
251 struct timer_list t2_timer; /* Retransmit timer for commands */
252 int cretries; /* Command retry counter */
253 struct gsm_control *pending_cmd;/* Our current pending command */
254 spinlock_t control_lock; /* Protects the pending command */
257 int adaption; /* 1 or 2 supported */
258 u8 ftype; /* UI or UIH */
259 int t1, t2; /* Timers in 1/100th of a sec */
260 int n2; /* Retry count */
262 /* Statistics (not currently exposed) */
263 unsigned long bad_fcs;
264 unsigned long malformed;
265 unsigned long io_error;
266 unsigned long bad_size;
267 unsigned long unsupported;
272 * Mux objects - needed so that we can translate a tty index into the
273 * relevant mux and DLCI.
276 #define MAX_MUX 4 /* 256 minors */
277 static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */
278 static spinlock_t gsm_mux_lock;
280 static struct tty_driver *gsm_tty_driver;
283 * This section of the driver logic implements the GSM encodings
284 * both the basic and the 'advanced'. Reliable transport is not
292 /* I is special: the rest are ..*/
303 /* Channel commands */
305 #define CMD_TEST 0x11
308 #define CMD_FCOFF 0x31
311 #define CMD_FCON 0x51
316 /* Virtual modem bits */
323 #define GSM0_SOF 0xF9
324 #define GSM1_SOF 0x7E
325 #define GSM1_ESCAPE 0x7D
326 #define GSM1_ESCAPE_BITS 0x20
330 static const struct tty_port_operations gsm_port_ops;
333 * CRC table for GSM 0710
336 static const u8 gsm_fcs8[256] = {
337 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75,
338 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B,
339 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69,
340 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67,
341 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D,
342 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43,
343 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51,
344 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F,
345 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05,
346 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B,
347 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19,
348 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17,
349 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D,
350 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33,
351 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21,
352 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F,
353 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95,
354 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B,
355 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89,
356 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87,
357 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD,
358 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3,
359 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1,
360 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF,
361 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5,
362 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB,
363 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9,
364 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7,
365 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD,
366 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3,
367 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1,
368 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF
371 #define INIT_FCS 0xFF
372 #define GOOD_FCS 0xCF
375 * gsm_fcs_add - update FCS
379 * Update the FCS to include c. Uses the algorithm in the specification
383 static inline u8 gsm_fcs_add(u8 fcs, u8 c)
385 return gsm_fcs8[fcs ^ c];
389 * gsm_fcs_add_block - update FCS for a block
392 * @len: length of buffer
394 * Update the FCS to include c. Uses the algorithm in the specification
398 static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len)
401 fcs = gsm_fcs8[fcs ^ *c++];
406 * gsm_read_ea - read a byte into an EA
407 * @val: variable holding value
408 * c: byte going into the EA
410 * Processes one byte of an EA. Updates the passed variable
411 * and returns 1 if the EA is now completely read
414 static int gsm_read_ea(unsigned int *val, u8 c)
416 /* Add the next 7 bits into the value */
419 /* Was this the last byte of the EA 1 = yes*/
424 * gsm_encode_modem - encode modem data bits
425 * @dlci: DLCI to encode from
427 * Returns the correct GSM encoded modem status bits (6 bit field) for
428 * the current status of the DLCI and attached tty object
431 static u8 gsm_encode_modem(const struct gsm_dlci *dlci)
434 /* FC is true flow control not modem bits */
437 if (dlci->modem_tx & TIOCM_DTR)
438 modembits |= MDM_RTC;
439 if (dlci->modem_tx & TIOCM_RTS)
440 modembits |= MDM_RTR;
441 if (dlci->modem_tx & TIOCM_RI)
443 if (dlci->modem_tx & TIOCM_CD)
449 * gsm_print_packet - display a frame for debug
450 * @hdr: header to print before decode
451 * @addr: address EA from the frame
452 * @cr: C/R bit from the frame
453 * @control: control including PF bit
454 * @data: following data bytes
455 * @dlen: length of data
457 * Displays a packet in human readable format for debugging purposes. The
458 * style is based on amateur radio LAP-B dump display.
461 static void gsm_print_packet(const char *hdr, int addr, int cr,
462 u8 control, const u8 *data, int dlen)
467 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]);
469 switch (control & ~PF) {
489 if (!(control & 0x01)) {
490 pr_cont("I N(S)%d N(R)%d",
491 (control & 0x0E) >> 1, (control & 0xE) >> 5);
492 } else switch (control & 0x0F) {
494 pr_cont("RR(%d)", (control & 0xE0) >> 5);
497 pr_cont("RNR(%d)", (control & 0xE0) >> 5);
500 pr_cont("REJ(%d)", (control & 0xE0) >> 5);
503 pr_cont("[%02X]", control);
519 pr_cont("%02X ", *data++);
528 * Link level transmission side
532 * gsm_stuff_packet - bytestuff a packet
535 * @len: length of input
537 * Expand a buffer by bytestuffing it. The worst case size change
538 * is doubling and the caller is responsible for handing out
539 * suitable sized buffers.
542 static int gsm_stuff_frame(const u8 *input, u8 *output, int len)
546 if (*input == GSM1_SOF || *input == GSM1_ESCAPE
547 || *input == XON || *input == XOFF) {
548 *output++ = GSM1_ESCAPE;
549 *output++ = *input++ ^ GSM1_ESCAPE_BITS;
552 *output++ = *input++;
559 * gsm_send - send a control frame
561 * @addr: address for control frame
562 * @cr: command/response bit
563 * @control: control byte including PF bit
565 * Format up and transmit a control frame. These do not go via the
566 * queueing logic as they should be transmitted ahead of data when
569 * FIXME: Lock versus data TX path
572 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 gsm->output(gsm, cbuf, len);
607 gsm_print_packet("-->", addr, cr, control, NULL, 0);
611 * gsm_response - send a control response
613 * @addr: address for control frame
614 * @control: control byte including PF bit
616 * Format up and transmit a link level response frame.
619 static inline void gsm_response(struct gsm_mux *gsm, int addr, int control)
621 gsm_send(gsm, addr, 0, control);
625 * gsm_command - send a control command
627 * @addr: address for control frame
628 * @control: control byte including PF bit
630 * Format up and transmit a link level command frame.
633 static inline void gsm_command(struct gsm_mux *gsm, int addr, int control)
635 gsm_send(gsm, addr, 1, control);
638 /* Data transmission */
640 #define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */
643 * gsm_data_alloc - allocate data frame
645 * @addr: DLCI address
646 * @len: length excluding header and FCS
647 * @ctrl: control byte
649 * Allocate a new data buffer for sending frames with data. Space is left
650 * at the front for header bytes but that is treated as an implementation
651 * detail and not for the high level code to use
654 static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
657 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN,
661 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */
670 * gsm_data_kick - poke the queue
673 * The tty device has called us to indicate that room has appeared in
674 * the transmit queue. Ram more data into the pipe if we have any
676 * FIXME: lock against link layer control transmissions
679 static void gsm_data_kick(struct gsm_mux *gsm)
681 struct gsm_msg *msg = gsm->tx_head;
685 /* FIXME: We need to apply this solely to data messages */
686 if (gsm->constipated)
689 while (gsm->tx_head != NULL) {
691 if (gsm->encoding != 0) {
692 gsm->txframe[0] = GSM1_SOF;
693 len = gsm_stuff_frame(msg->data,
694 gsm->txframe + 1, msg->len);
695 gsm->txframe[len + 1] = GSM1_SOF;
698 gsm->txframe[0] = GSM0_SOF;
699 memcpy(gsm->txframe + 1 , msg->data, msg->len);
700 gsm->txframe[msg->len + 1] = GSM0_SOF;
705 print_hex_dump_bytes("gsm_data_kick: ",
709 if (gsm->output(gsm, gsm->txframe + skip_sof,
712 /* FIXME: Can eliminate one SOF in many more cases */
713 gsm->tx_head = msg->next;
714 if (gsm->tx_head == NULL)
716 gsm->tx_bytes -= msg->len;
718 /* For a burst of frames skip the extra SOF within the
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 */
771 gsm->tx_tail->next = msg;
775 gsm->tx_bytes += msg->len;
780 * gsm_data_queue - queue a UI or UIH frame
781 * @dlci: DLCI sending the data
782 * @msg: message queued
784 * Add data to the transmit queue and try and get stuff moving
785 * out of the mux tty if not already doing so. Take the
786 * the gsm tx lock and dlci lock.
789 static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
792 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
793 __gsm_data_queue(dlci, msg);
794 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
798 * gsm_dlci_data_output - try and push data out of a DLCI
800 * @dlci: the DLCI to pull data from
802 * Pull data from a DLCI and send it into the transmit queue if there
803 * is data. Keep to the MRU of the mux. This path handles the usual tty
804 * interface which is a byte stream with optional modem data.
806 * Caller must hold the tx_lock of the mux.
809 static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci)
814 int h = dlci->adaption - 1;
816 len = kfifo_len(dlci->fifo);
820 /* MTU/MRU count only the data bits */
826 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
827 /* FIXME: need a timer or something to kick this so it can't
828 get stuck with no work outstanding and no buffer free */
832 switch (dlci->adaption) {
833 case 1: /* Unstructured */
835 case 2: /* Unstructed with modem bits. Always one byte as we never
836 send inline break data */
837 *dp += gsm_encode_modem(dlci);
841 WARN_ON(kfifo_out_locked(dlci->fifo, dp , len, &dlci->lock) != len);
842 __gsm_data_queue(dlci, msg);
843 /* Bytes of data we used up */
848 * gsm_dlci_data_output_framed - try and push data out of a DLCI
850 * @dlci: the DLCI to pull data from
852 * Pull data from a DLCI and send it into the transmit queue if there
853 * is data. Keep to the MRU of the mux. This path handles framed data
854 * queued as skbuffs to the DLCI.
856 * Caller must hold the tx_lock of the mux.
859 static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
860 struct gsm_dlci *dlci)
865 int last = 0, first = 0;
868 /* One byte per frame is used for B/F flags */
869 if (dlci->adaption == 4)
872 /* dlci->skb is locked by tx_lock */
873 if (dlci->skb == NULL) {
874 dlci->skb = skb_dequeue(&dlci->skb_list);
875 if (dlci->skb == NULL)
879 len = dlci->skb->len + overhead;
881 /* MTU/MRU count only the data bits */
882 if (len > gsm->mtu) {
883 if (dlci->adaption == 3) {
884 /* Over long frame, bin it */
885 kfree_skb(dlci->skb);
893 size = len + overhead;
894 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
896 /* FIXME: need a timer or something to kick this so it can't
897 get stuck with no work outstanding and no buffer free */
902 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */
903 /* Flag byte to carry the start/end info */
904 *dp++ = last << 7 | first << 6 | 1; /* EA */
907 memcpy(dp, skb_pull(dlci->skb, len), len);
908 __gsm_data_queue(dlci, msg);
910 kfree_skb(dlci->skb);
917 * gsm_dlci_data_sweep - look for data to send
920 * Sweep the GSM mux channels in priority order looking for ones with
921 * data to send. We could do with optimising this scan a bit. We aim
922 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit
923 * TX_THRESH_LO we get called again
925 * FIXME: We should round robin between groups and in theory you can
926 * renegotiate DLCI priorities with optional stuff. Needs optimising.
929 static void gsm_dlci_data_sweep(struct gsm_mux *gsm)
932 /* Priority ordering: We should do priority with RR of the groups */
935 while (i < NUM_DLCI) {
936 struct gsm_dlci *dlci;
938 if (gsm->tx_bytes > TX_THRESH_HI)
941 if (dlci == NULL || dlci->constipated) {
945 if (dlci->adaption < 3 && !dlci->net)
946 len = gsm_dlci_data_output(gsm, dlci);
948 len = gsm_dlci_data_output_framed(gsm, dlci);
951 /* DLCI empty - try the next */
958 * gsm_dlci_data_kick - transmit if possible
959 * @dlci: DLCI to kick
961 * Transmit data from this DLCI if the queue is empty. We can't rely on
962 * a tty wakeup except when we filled the pipe so we need to fire off
963 * new data ourselves in other cases.
966 static void gsm_dlci_data_kick(struct gsm_dlci *dlci)
970 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
971 /* If we have nothing running then we need to fire up */
972 if (dlci->gsm->tx_bytes == 0) {
974 gsm_dlci_data_output_framed(dlci->gsm, dlci);
976 gsm_dlci_data_output(dlci->gsm, dlci);
977 } else if (dlci->gsm->tx_bytes < TX_THRESH_LO)
978 gsm_dlci_data_sweep(dlci->gsm);
979 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
983 * Control message processing
988 * gsm_control_reply - send a response frame to a control
990 * @cmd: the command to use
991 * @data: data to follow encoded info
992 * @dlen: length of data
994 * Encode up and queue a UI/UIH frame containing our response.
997 static void gsm_control_reply(struct gsm_mux *gsm, int cmd, u8 *data,
1000 struct gsm_msg *msg;
1001 msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype);
1004 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */
1005 msg->data[1] = (dlen << 1) | EA;
1006 memcpy(msg->data + 2, data, dlen);
1007 gsm_data_queue(gsm->dlci[0], msg);
1011 * gsm_process_modem - process received modem status
1012 * @tty: virtual tty bound to the DLCI
1013 * @dlci: DLCI to affect
1014 * @modem: modem bits (full EA)
1016 * Used when a modem control message or line state inline in adaption
1017 * layer 2 is processed. Sort out the local modem state and throttles
1020 static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
1024 u8 brk = modem >> 6;
1026 /* Flow control/ready to communicate */
1027 if (modem & MDM_FC) {
1028 /* Need to throttle our output on this device */
1029 dlci->constipated = 1;
1031 if (modem & MDM_RTC) {
1032 mlines |= TIOCM_DSR | TIOCM_DTR;
1033 dlci->constipated = 0;
1034 gsm_dlci_data_kick(dlci);
1036 /* Map modem bits */
1037 if (modem & MDM_RTR)
1038 mlines |= TIOCM_RTS | TIOCM_CTS;
1044 /* Carrier drop -> hangup */
1046 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD))
1047 if (!(tty->termios->c_cflag & CLOCAL))
1050 tty_insert_flip_char(tty, 0, TTY_BREAK);
1052 dlci->modem_rx = mlines;
1056 * gsm_control_modem - modem status received
1058 * @data: data following command
1059 * @clen: command length
1061 * We have received a modem status control message. This is used by
1062 * the GSM mux protocol to pass virtual modem line status and optionally
1063 * to indicate break signals. Unpack it, convert to Linux representation
1064 * and if need be stuff a break message down the tty.
1067 static void gsm_control_modem(struct gsm_mux *gsm, u8 *data, int clen)
1069 unsigned int addr = 0;
1070 unsigned int modem = 0;
1071 struct gsm_dlci *dlci;
1074 struct tty_struct *tty;
1076 while (gsm_read_ea(&addr, *dp++) == 0) {
1081 /* Must be at least one byte following the EA */
1087 /* Closed port, or invalid ? */
1088 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1090 dlci = gsm->dlci[addr];
1092 while (gsm_read_ea(&modem, *dp++) == 0) {
1097 tty = tty_port_tty_get(&dlci->port);
1098 gsm_process_modem(tty, dlci, modem);
1103 gsm_control_reply(gsm, CMD_MSC, data, clen);
1107 * gsm_control_rls - remote line status
1110 * @clen: data length
1112 * The modem sends us a two byte message on the control channel whenever
1113 * it wishes to send us an error state from the virtual link. Stuff
1114 * this into the uplink tty if present
1117 static void gsm_control_rls(struct gsm_mux *gsm, u8 *data, int clen)
1119 struct tty_struct *tty;
1120 unsigned int addr = 0 ;
1125 while (gsm_read_ea(&addr, *dp++) == 0) {
1130 /* Must be at least one byte following ea */
1135 /* Closed port, or invalid ? */
1136 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1140 if ((bits & 1) == 0)
1142 /* See if we have an uplink tty */
1143 tty = tty_port_tty_get(&gsm->dlci[addr]->port);
1147 tty_insert_flip_char(tty, 0, TTY_OVERRUN);
1149 tty_insert_flip_char(tty, 0, TTY_PARITY);
1151 tty_insert_flip_char(tty, 0, TTY_FRAME);
1152 tty_flip_buffer_push(tty);
1155 gsm_control_reply(gsm, CMD_RLS, data, clen);
1158 static void gsm_dlci_begin_close(struct gsm_dlci *dlci);
1161 * gsm_control_message - DLCI 0 control processing
1163 * @command: the command EA
1164 * @data: data beyond the command/length EAs
1167 * Input processor for control messages from the other end of the link.
1168 * Processes the incoming request and queues a response frame or an
1169 * NSC response if not supported
1172 static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
1178 struct gsm_dlci *dlci = gsm->dlci[0];
1179 /* Modem wishes to close down */
1183 gsm_dlci_begin_close(dlci);
1188 /* Modem wishes to test, reply with the data */
1189 gsm_control_reply(gsm, CMD_TEST, data, clen);
1192 /* Modem wants us to STFU */
1193 gsm->constipated = 1;
1194 gsm_control_reply(gsm, CMD_FCON, NULL, 0);
1197 /* Modem can accept data again */
1198 gsm->constipated = 0;
1199 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0);
1200 /* Kick the link in case it is idling */
1204 /* Out of band modem line change indicator for a DLCI */
1205 gsm_control_modem(gsm, data, clen);
1208 /* Out of band error reception for a DLCI */
1209 gsm_control_rls(gsm, data, clen);
1212 /* Modem wishes to enter power saving state */
1213 gsm_control_reply(gsm, CMD_PSC, NULL, 0);
1215 /* Optional unsupported commands */
1216 case CMD_PN: /* Parameter negotiation */
1217 case CMD_RPN: /* Remote port negotiation */
1218 case CMD_SNC: /* Service negotiation command */
1220 /* Reply to bad commands with an NSC */
1222 gsm_control_reply(gsm, CMD_NSC, buf, 1);
1228 * gsm_control_response - process a response to our control
1230 * @command: the command (response) EA
1231 * @data: data beyond the command/length EA
1234 * Process a response to an outstanding command. We only allow a single
1235 * control message in flight so this is fairly easy. All the clean up
1236 * is done by the caller, we just update the fields, flag it as done
1240 static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
1243 struct gsm_control *ctrl;
1244 unsigned long flags;
1246 spin_lock_irqsave(&gsm->control_lock, flags);
1248 ctrl = gsm->pending_cmd;
1249 /* Does the reply match our command */
1251 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) {
1252 /* Our command was replied to, kill the retry timer */
1253 del_timer(&gsm->t2_timer);
1254 gsm->pending_cmd = NULL;
1255 /* Rejected by the other end */
1256 if (command == CMD_NSC)
1257 ctrl->error = -EOPNOTSUPP;
1259 wake_up(&gsm->event);
1261 spin_unlock_irqrestore(&gsm->control_lock, flags);
1265 * gsm_control_transmit - send control packet
1267 * @ctrl: frame to send
1269 * Send out a pending control command (called under control lock)
1272 static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl)
1274 struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, gsm->ftype);
1277 msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */
1278 memcpy(msg->data + 1, ctrl->data, ctrl->len);
1279 gsm_data_queue(gsm->dlci[0], msg);
1283 * gsm_control_retransmit - retransmit a control frame
1284 * @data: pointer to our gsm object
1286 * Called off the T2 timer expiry in order to retransmit control frames
1287 * that have been lost in the system somewhere. The control_lock protects
1288 * us from colliding with another sender or a receive completion event.
1289 * In that situation the timer may still occur in a small window but
1290 * gsm->pending_cmd will be NULL and we just let the timer expire.
1293 static void gsm_control_retransmit(unsigned long data)
1295 struct gsm_mux *gsm = (struct gsm_mux *)data;
1296 struct gsm_control *ctrl;
1297 unsigned long flags;
1298 spin_lock_irqsave(&gsm->control_lock, flags);
1299 ctrl = gsm->pending_cmd;
1302 if (gsm->cretries == 0) {
1303 gsm->pending_cmd = NULL;
1304 ctrl->error = -ETIMEDOUT;
1306 spin_unlock_irqrestore(&gsm->control_lock, flags);
1307 wake_up(&gsm->event);
1310 gsm_control_transmit(gsm, ctrl);
1311 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1313 spin_unlock_irqrestore(&gsm->control_lock, flags);
1317 * gsm_control_send - send a control frame on DLCI 0
1318 * @gsm: the GSM channel
1319 * @command: command to send including CR bit
1320 * @data: bytes of data (must be kmalloced)
1321 * @len: length of the block to send
1323 * Queue and dispatch a control command. Only one command can be
1324 * active at a time. In theory more can be outstanding but the matching
1325 * gets really complicated so for now stick to one outstanding.
1328 static struct gsm_control *gsm_control_send(struct gsm_mux *gsm,
1329 unsigned int command, u8 *data, int clen)
1331 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control),
1333 unsigned long flags;
1337 wait_event(gsm->event, gsm->pending_cmd == NULL);
1338 spin_lock_irqsave(&gsm->control_lock, flags);
1339 if (gsm->pending_cmd != NULL) {
1340 spin_unlock_irqrestore(&gsm->control_lock, flags);
1343 ctrl->cmd = command;
1346 gsm->pending_cmd = ctrl;
1347 gsm->cretries = gsm->n2;
1348 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1349 gsm_control_transmit(gsm, ctrl);
1350 spin_unlock_irqrestore(&gsm->control_lock, flags);
1355 * gsm_control_wait - wait for a control to finish
1357 * @control: control we are waiting on
1359 * Waits for the control to complete or time out. Frees any used
1360 * resources and returns 0 for success, or an error if the remote
1361 * rejected or ignored the request.
1364 static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
1367 wait_event(gsm->event, control->done == 1);
1368 err = control->error;
1375 * DLCI level handling: Needs krefs
1379 * State transitions and timers
1383 * gsm_dlci_close - a DLCI has closed
1384 * @dlci: DLCI that closed
1386 * Perform processing when moving a DLCI into closed state. If there
1387 * is an attached tty this is hung up
1390 static void gsm_dlci_close(struct gsm_dlci *dlci)
1392 del_timer(&dlci->t1);
1394 pr_debug("DLCI %d goes closed.\n", dlci->addr);
1395 dlci->state = DLCI_CLOSED;
1396 if (dlci->addr != 0) {
1397 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1402 kfifo_reset(dlci->fifo);
1404 dlci->gsm->dead = 1;
1405 wake_up(&dlci->gsm->event);
1406 /* A DLCI 0 close is a MUX termination so we need to kick that
1407 back to userspace somehow */
1411 * gsm_dlci_open - a DLCI has opened
1412 * @dlci: DLCI that opened
1414 * Perform processing when moving a DLCI into open state.
1417 static void gsm_dlci_open(struct gsm_dlci *dlci)
1419 /* Note that SABM UA .. SABM UA first UA lost can mean that we go
1421 del_timer(&dlci->t1);
1422 /* This will let a tty open continue */
1423 dlci->state = DLCI_OPEN;
1425 pr_debug("DLCI %d goes open.\n", dlci->addr);
1426 wake_up(&dlci->gsm->event);
1430 * gsm_dlci_t1 - T1 timer expiry
1431 * @dlci: DLCI that opened
1433 * The T1 timer handles retransmits of control frames (essentially of
1434 * SABM and DISC). We resend the command until the retry count runs out
1435 * in which case an opening port goes back to closed and a closing port
1436 * is simply put into closed state (any further frames from the other
1437 * end will get a DM response)
1440 static void gsm_dlci_t1(unsigned long data)
1442 struct gsm_dlci *dlci = (struct gsm_dlci *)data;
1443 struct gsm_mux *gsm = dlci->gsm;
1445 switch (dlci->state) {
1448 if (dlci->retries) {
1449 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1450 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1452 gsm_dlci_close(dlci);
1456 if (dlci->retries) {
1457 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1458 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1460 gsm_dlci_close(dlci);
1466 * gsm_dlci_begin_open - start channel open procedure
1467 * @dlci: DLCI to open
1469 * Commence opening a DLCI from the Linux side. We issue SABM messages
1470 * to the modem which should then reply with a UA, at which point we
1471 * will move into open state. Opening is done asynchronously with retry
1472 * running off timers and the responses.
1475 static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
1477 struct gsm_mux *gsm = dlci->gsm;
1478 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING)
1480 dlci->retries = gsm->n2;
1481 dlci->state = DLCI_OPENING;
1482 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1483 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1487 * gsm_dlci_begin_close - start channel open procedure
1488 * @dlci: DLCI to open
1490 * Commence closing a DLCI from the Linux side. We issue DISC messages
1491 * to the modem which should then reply with a UA, at which point we
1492 * will move into closed state. Closing is done asynchronously with retry
1493 * off timers. We may also receive a DM reply from the other end which
1494 * indicates the channel was already closed.
1497 static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
1499 struct gsm_mux *gsm = dlci->gsm;
1500 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
1502 dlci->retries = gsm->n2;
1503 dlci->state = DLCI_CLOSING;
1504 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1505 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1509 * gsm_dlci_data - data arrived
1511 * @data: block of bytes received
1512 * @len: length of received block
1514 * A UI or UIH frame has arrived which contains data for a channel
1515 * other than the control channel. If the relevant virtual tty is
1516 * open we shovel the bits down it, if not we drop them.
1519 static void gsm_dlci_data(struct gsm_dlci *dlci, u8 *data, int len)
1522 struct tty_port *port = &dlci->port;
1523 struct tty_struct *tty = tty_port_tty_get(port);
1524 unsigned int modem = 0;
1527 pr_debug("%d bytes for tty %p\n", len, tty);
1529 switch (dlci->adaption) {
1530 /* Unsupported types */
1531 /* Packetised interruptible data */
1534 /* Packetised uininterruptible voice/data */
1537 /* Asynchronous serial with line state in each frame */
1539 while (gsm_read_ea(&modem, *data++) == 0) {
1544 gsm_process_modem(tty, dlci, modem);
1545 /* Line state will go via DLCI 0 controls only */
1548 tty_insert_flip_string(tty, data, len);
1549 tty_flip_buffer_push(tty);
1556 * gsm_dlci_control - data arrived on control channel
1558 * @data: block of bytes received
1559 * @len: length of received block
1561 * A UI or UIH frame has arrived which contains data for DLCI 0 the
1562 * control channel. This should contain a command EA followed by
1563 * control data bytes. The command EA contains a command/response bit
1564 * and we divide up the work accordingly.
1567 static void gsm_dlci_command(struct gsm_dlci *dlci, u8 *data, int len)
1569 /* See what command is involved */
1570 unsigned int command = 0;
1572 if (gsm_read_ea(&command, *data++) == 1) {
1575 /* FIXME: this is properly an EA */
1577 /* Malformed command ? */
1581 gsm_control_message(dlci->gsm, command,
1584 gsm_control_response(dlci->gsm, command,
1592 * Allocate/Free DLCI channels
1596 * gsm_dlci_alloc - allocate a DLCI
1598 * @addr: address of the DLCI
1600 * Allocate and install a new DLCI object into the GSM mux.
1602 * FIXME: review locking races
1605 static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
1607 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC);
1610 spin_lock_init(&dlci->lock);
1611 kref_init(&dlci->ref);
1612 mutex_init(&dlci->mutex);
1613 dlci->fifo = &dlci->_fifo;
1614 if (kfifo_alloc(&dlci->_fifo, 4096, GFP_KERNEL) < 0) {
1619 skb_queue_head_init(&dlci->skb_list);
1620 init_timer(&dlci->t1);
1621 dlci->t1.function = gsm_dlci_t1;
1622 dlci->t1.data = (unsigned long)dlci;
1623 tty_port_init(&dlci->port);
1624 dlci->port.ops = &gsm_port_ops;
1627 dlci->adaption = gsm->adaption;
1628 dlci->state = DLCI_CLOSED;
1630 dlci->data = gsm_dlci_data;
1632 dlci->data = gsm_dlci_command;
1633 gsm->dlci[addr] = dlci;
1638 * gsm_dlci_free - free DLCI
1639 * @dlci: DLCI to free
1645 static void gsm_dlci_free(struct kref *ref)
1647 struct gsm_dlci *dlci = container_of(ref, struct gsm_dlci, ref);
1649 del_timer_sync(&dlci->t1);
1650 dlci->gsm->dlci[dlci->addr] = NULL;
1651 kfifo_free(dlci->fifo);
1652 while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
1653 kfree_skb(dlci->skb);
1657 static inline void dlci_get(struct gsm_dlci *dlci)
1659 kref_get(&dlci->ref);
1662 static inline void dlci_put(struct gsm_dlci *dlci)
1664 kref_put(&dlci->ref, gsm_dlci_free);
1668 * gsm_dlci_release - release DLCI
1669 * @dlci: DLCI to destroy
1671 * Release a DLCI. Actual free is deferred until either
1672 * mux is closed or tty is closed - whichever is last.
1676 static void gsm_dlci_release(struct gsm_dlci *dlci)
1678 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1687 * LAPBish link layer logic
1691 * gsm_queue - a GSM frame is ready to process
1692 * @gsm: pointer to our gsm mux
1694 * At this point in time a frame has arrived and been demangled from
1695 * the line encoding. All the differences between the encodings have
1696 * been handled below us and the frame is unpacked into the structures.
1697 * The fcs holds the header FCS but any data FCS must be added here.
1700 static void gsm_queue(struct gsm_mux *gsm)
1702 struct gsm_dlci *dlci;
1705 /* We have to sneak a look at the packet body to do the FCS.
1706 A somewhat layering violation in the spec */
1708 if ((gsm->control & ~PF) == UI)
1709 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len);
1710 if (gsm->encoding == 0){
1711 /* WARNING: gsm->received_fcs is used for gsm->encoding = 0 only.
1712 In this case it contain the last piece of data
1713 required to generate final CRC */
1714 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs);
1716 if (gsm->fcs != GOOD_FCS) {
1719 pr_debug("BAD FCS %02x\n", gsm->fcs);
1722 address = gsm->address >> 1;
1723 if (address >= NUM_DLCI)
1726 cr = gsm->address & 1; /* C/R bit */
1728 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
1730 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */
1731 dlci = gsm->dlci[address];
1733 switch (gsm->control) {
1738 dlci = gsm_dlci_alloc(gsm, address);
1742 gsm_response(gsm, address, DM);
1744 gsm_response(gsm, address, UA);
1745 gsm_dlci_open(dlci);
1751 if (dlci == NULL || dlci->state == DLCI_CLOSED) {
1752 gsm_response(gsm, address, DM);
1755 /* Real close complete */
1756 gsm_response(gsm, address, UA);
1757 gsm_dlci_close(dlci);
1761 if (cr == 0 || dlci == NULL)
1763 switch (dlci->state) {
1765 gsm_dlci_close(dlci);
1768 gsm_dlci_open(dlci);
1772 case DM: /* DM can be valid unsolicited */
1778 gsm_dlci_close(dlci);
1788 if (dlci == NULL || dlci->state != DLCI_OPEN) {
1789 gsm_command(gsm, address, DM|PF);
1792 dlci->data(dlci, gsm->buf, gsm->len);
1805 * gsm0_receive - perform processing for non-transparency
1806 * @gsm: gsm data for this ldisc instance
1809 * Receive bytes in gsm mode 0
1812 static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
1816 switch (gsm->state) {
1817 case GSM_SEARCH: /* SOF marker */
1818 if (c == GSM0_SOF) {
1819 gsm->state = GSM_ADDRESS;
1822 gsm->fcs = INIT_FCS;
1825 case GSM_ADDRESS: /* Address EA */
1826 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1827 if (gsm_read_ea(&gsm->address, c))
1828 gsm->state = GSM_CONTROL;
1830 case GSM_CONTROL: /* Control Byte */
1831 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1833 gsm->state = GSM_LEN0;
1835 case GSM_LEN0: /* Length EA */
1836 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1837 if (gsm_read_ea(&gsm->len, c)) {
1838 if (gsm->len > gsm->mru) {
1840 gsm->state = GSM_SEARCH;
1845 gsm->state = GSM_FCS;
1847 gsm->state = GSM_DATA;
1850 gsm->state = GSM_LEN1;
1853 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1855 gsm->len |= len << 7;
1856 if (gsm->len > gsm->mru) {
1858 gsm->state = GSM_SEARCH;
1863 gsm->state = GSM_FCS;
1865 gsm->state = GSM_DATA;
1867 case GSM_DATA: /* Data */
1868 gsm->buf[gsm->count++] = c;
1869 if (gsm->count == gsm->len)
1870 gsm->state = GSM_FCS;
1872 case GSM_FCS: /* FCS follows the packet */
1873 gsm->received_fcs = c;
1875 gsm->state = GSM_SSOF;
1878 if (c == GSM0_SOF) {
1879 gsm->state = GSM_SEARCH;
1887 * gsm1_receive - perform processing for non-transparency
1888 * @gsm: gsm data for this ldisc instance
1891 * Receive bytes in mode 1 (Advanced option)
1894 static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
1896 if (c == GSM1_SOF) {
1897 /* EOF is only valid in frame if we have got to the data state
1898 and received at least one byte (the FCS) */
1899 if (gsm->state == GSM_DATA && gsm->count) {
1900 /* Extract the FCS */
1902 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
1903 gsm->len = gsm->count;
1905 gsm->state = GSM_START;
1908 /* Any partial frame was a runt so go back to start */
1909 if (gsm->state != GSM_START) {
1911 gsm->state = GSM_START;
1913 /* A SOF in GSM_START means we are still reading idling or
1918 if (c == GSM1_ESCAPE) {
1923 /* Only an unescaped SOF gets us out of GSM search */
1924 if (gsm->state == GSM_SEARCH)
1928 c ^= GSM1_ESCAPE_BITS;
1931 switch (gsm->state) {
1932 case GSM_START: /* First byte after SOF */
1934 gsm->state = GSM_ADDRESS;
1935 gsm->fcs = INIT_FCS;
1937 case GSM_ADDRESS: /* Address continuation */
1938 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1939 if (gsm_read_ea(&gsm->address, c))
1940 gsm->state = GSM_CONTROL;
1942 case GSM_CONTROL: /* Control Byte */
1943 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1946 gsm->state = GSM_DATA;
1948 case GSM_DATA: /* Data */
1949 if (gsm->count > gsm->mru) { /* Allow one for the FCS */
1950 gsm->state = GSM_OVERRUN;
1953 gsm->buf[gsm->count++] = c;
1955 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */
1961 * gsm_error - handle tty error
1963 * @data: byte received (may be invalid)
1964 * @flag: error received
1966 * Handle an error in the receipt of data for a frame. Currently we just
1967 * go back to hunting for a SOF.
1969 * FIXME: better diagnostics ?
1972 static void gsm_error(struct gsm_mux *gsm,
1973 unsigned char data, unsigned char flag)
1975 gsm->state = GSM_SEARCH;
1980 * gsm_cleanup_mux - generic GSM protocol cleanup
1983 * Clean up the bits of the mux which are the same for all framing
1984 * protocols. Remove the mux from the mux table, stop all the timers
1985 * and then shut down each device hanging up the channels as we go.
1988 void gsm_cleanup_mux(struct gsm_mux *gsm)
1991 struct gsm_dlci *dlci = gsm->dlci[0];
1992 struct gsm_msg *txq;
1996 spin_lock(&gsm_mux_lock);
1997 for (i = 0; i < MAX_MUX; i++) {
1998 if (gsm_mux[i] == gsm) {
2003 spin_unlock(&gsm_mux_lock);
2004 WARN_ON(i == MAX_MUX);
2006 del_timer_sync(&gsm->t2_timer);
2007 /* Now we are sure T2 has stopped */
2010 gsm_dlci_begin_close(dlci);
2011 wait_event_interruptible(gsm->event,
2012 dlci->state == DLCI_CLOSED);
2014 /* Free up any link layer users */
2015 for (i = 0; i < NUM_DLCI; i++)
2017 gsm_dlci_release(gsm->dlci[i]);
2018 /* Now wipe the queues */
2019 for (txq = gsm->tx_head; txq != NULL; txq = gsm->tx_head) {
2020 gsm->tx_head = txq->next;
2023 gsm->tx_tail = NULL;
2025 EXPORT_SYMBOL_GPL(gsm_cleanup_mux);
2028 * gsm_activate_mux - generic GSM setup
2031 * Set up the bits of the mux which are the same for all framing
2032 * protocols. Add the mux to the mux table so it can be opened and
2033 * finally kick off connecting to DLCI 0 on the modem.
2036 int gsm_activate_mux(struct gsm_mux *gsm)
2038 struct gsm_dlci *dlci;
2041 init_timer(&gsm->t2_timer);
2042 gsm->t2_timer.function = gsm_control_retransmit;
2043 gsm->t2_timer.data = (unsigned long)gsm;
2044 init_waitqueue_head(&gsm->event);
2045 spin_lock_init(&gsm->control_lock);
2046 spin_lock_init(&gsm->tx_lock);
2048 if (gsm->encoding == 0)
2049 gsm->receive = gsm0_receive;
2051 gsm->receive = gsm1_receive;
2052 gsm->error = gsm_error;
2054 spin_lock(&gsm_mux_lock);
2055 for (i = 0; i < MAX_MUX; i++) {
2056 if (gsm_mux[i] == NULL) {
2062 spin_unlock(&gsm_mux_lock);
2066 dlci = gsm_dlci_alloc(gsm, 0);
2069 gsm->dead = 0; /* Tty opens are now permissible */
2072 EXPORT_SYMBOL_GPL(gsm_activate_mux);
2075 * gsm_free_mux - free up a mux
2078 * Dispose of allocated resources for a dead mux
2080 void gsm_free_mux(struct gsm_mux *gsm)
2082 kfree(gsm->txframe);
2086 EXPORT_SYMBOL_GPL(gsm_free_mux);
2089 * gsm_free_muxr - free up a mux
2092 * Dispose of allocated resources for a dead mux
2094 static void gsm_free_muxr(struct kref *ref)
2096 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref);
2100 static inline void mux_get(struct gsm_mux *gsm)
2102 kref_get(&gsm->ref);
2105 static inline void mux_put(struct gsm_mux *gsm)
2107 kref_put(&gsm->ref, gsm_free_muxr);
2111 * gsm_alloc_mux - allocate a mux
2113 * Creates a new mux ready for activation.
2116 struct gsm_mux *gsm_alloc_mux(void)
2118 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
2121 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL);
2122 if (gsm->buf == NULL) {
2126 gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL);
2127 if (gsm->txframe == NULL) {
2132 spin_lock_init(&gsm->lock);
2133 kref_init(&gsm->ref);
2141 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
2143 gsm->dead = 1; /* Avoid early tty opens */
2147 EXPORT_SYMBOL_GPL(gsm_alloc_mux);
2150 * gsmld_output - write to link
2152 * @data: bytes to output
2155 * Write a block of data from the GSM mux to the data channel. This
2156 * will eventually be serialized from above but at the moment isn't.
2159 static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
2161 if (tty_write_room(gsm->tty) < len) {
2162 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
2166 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET,
2168 gsm->tty->ops->write(gsm->tty, data, len);
2173 * gsmld_attach_gsm - mode set up
2174 * @tty: our tty structure
2177 * Set up the MUX for basic mode and commence connecting to the
2178 * modem. Currently called from the line discipline set up but
2179 * will need moving to an ioctl path.
2182 static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2185 int base = gsm->num << 6; /* Base for this MUX */
2187 gsm->tty = tty_kref_get(tty);
2188 gsm->output = gsmld_output;
2189 ret = gsm_activate_mux(gsm);
2191 tty_kref_put(gsm->tty);
2193 /* Don't register device 0 - this is the control channel and not
2194 a usable tty interface */
2195 for (i = 1; i < NUM_DLCI; i++)
2196 tty_register_device(gsm_tty_driver, base + i, NULL);
2203 * gsmld_detach_gsm - stop doing 0710 mux
2204 * @tty: tty attached to the mux
2207 * Shutdown and then clean up the resources used by the line discipline
2210 static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2213 int base = gsm->num << 6; /* Base for this MUX */
2215 WARN_ON(tty != gsm->tty);
2216 for (i = 1; i < NUM_DLCI; i++)
2217 tty_unregister_device(gsm_tty_driver, base + i);
2218 gsm_cleanup_mux(gsm);
2219 tty_kref_put(gsm->tty);
2223 static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
2224 char *fp, int count)
2226 struct gsm_mux *gsm = tty->disc_data;
2227 const unsigned char *dp;
2234 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET,
2237 for (i = count, dp = cp, f = fp; i; i--, dp++) {
2241 gsm->receive(gsm, *dp);
2247 gsm->error(gsm, *dp, flags);
2250 WARN_ONCE("%s: unknown flag %d\n",
2251 tty_name(tty, buf), flags);
2255 /* FASYNC if needed ? */
2256 /* If clogged call tty_throttle(tty); */
2260 * gsmld_chars_in_buffer - report available bytes
2263 * Report the number of characters buffered to be delivered to user
2264 * at this instant in time.
2269 static ssize_t gsmld_chars_in_buffer(struct tty_struct *tty)
2275 * gsmld_flush_buffer - clean input queue
2276 * @tty: terminal device
2278 * Flush the input buffer. Called when the line discipline is
2279 * being closed, when the tty layer wants the buffer flushed (eg
2283 static void gsmld_flush_buffer(struct tty_struct *tty)
2288 * gsmld_close - close the ldisc for this tty
2291 * Called from the terminal layer when this line discipline is
2292 * being shut down, either because of a close or becsuse of a
2293 * discipline change. The function will not be called while other
2294 * ldisc methods are in progress.
2297 static void gsmld_close(struct tty_struct *tty)
2299 struct gsm_mux *gsm = tty->disc_data;
2301 gsmld_detach_gsm(tty, gsm);
2303 gsmld_flush_buffer(tty);
2304 /* Do other clean up here */
2309 * gsmld_open - open an ldisc
2310 * @tty: terminal to open
2312 * Called when this line discipline is being attached to the
2313 * terminal device. Can sleep. Called serialized so that no
2314 * other events will occur in parallel. No further open will occur
2318 static int gsmld_open(struct tty_struct *tty)
2320 struct gsm_mux *gsm;
2322 if (tty->ops->write == NULL)
2325 /* Attach our ldisc data */
2326 gsm = gsm_alloc_mux();
2330 tty->disc_data = gsm;
2331 tty->receive_room = 65536;
2333 /* Attach the initial passive connection */
2335 return gsmld_attach_gsm(tty, gsm);
2339 * gsmld_write_wakeup - asynchronous I/O notifier
2342 * Required for the ptys, serial driver etc. since processes
2343 * that attach themselves to the master and rely on ASYNC
2344 * IO must be woken up
2347 static void gsmld_write_wakeup(struct tty_struct *tty)
2349 struct gsm_mux *gsm = tty->disc_data;
2350 unsigned long flags;
2353 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2355 if (gsm->tx_bytes < TX_THRESH_LO) {
2356 spin_lock_irqsave(&gsm->tx_lock, flags);
2357 gsm_dlci_data_sweep(gsm);
2358 spin_unlock_irqrestore(&gsm->tx_lock, flags);
2363 * gsmld_read - read function for tty
2365 * @file: file object
2366 * @buf: userspace buffer pointer
2369 * Perform reads for the line discipline. We are guaranteed that the
2370 * line discipline will not be closed under us but we may get multiple
2371 * parallel readers and must handle this ourselves. We may also get
2372 * a hangup. Always called in user context, may sleep.
2374 * This code must be sure never to sleep through a hangup.
2377 static ssize_t gsmld_read(struct tty_struct *tty, struct file *file,
2378 unsigned char __user *buf, size_t nr)
2384 * gsmld_write - write function for tty
2386 * @file: file object
2387 * @buf: userspace buffer pointer
2390 * Called when the owner of the device wants to send a frame
2391 * itself (or some other control data). The data is transferred
2392 * as-is and must be properly framed and checksummed as appropriate
2393 * by userspace. Frames are either sent whole or not at all as this
2394 * avoids pain user side.
2397 static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
2398 const unsigned char *buf, size_t nr)
2400 int space = tty_write_room(tty);
2402 return tty->ops->write(tty, buf, nr);
2403 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2408 * gsmld_poll - poll method for N_GSM0710
2409 * @tty: terminal device
2410 * @file: file accessing it
2413 * Called when the line discipline is asked to poll() for data or
2414 * for special events. This code is not serialized with respect to
2415 * other events save open/close.
2417 * This code must be sure never to sleep through a hangup.
2418 * Called without the kernel lock held - fine
2421 static unsigned int gsmld_poll(struct tty_struct *tty, struct file *file,
2424 unsigned int mask = 0;
2425 struct gsm_mux *gsm = tty->disc_data;
2427 poll_wait(file, &tty->read_wait, wait);
2428 poll_wait(file, &tty->write_wait, wait);
2429 if (tty_hung_up_p(file))
2431 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
2432 mask |= POLLOUT | POLLWRNORM;
2438 static int gsmld_config(struct tty_struct *tty, struct gsm_mux *gsm,
2439 struct gsm_config *c)
2442 int need_restart = 0;
2444 /* Stuff we don't support yet - UI or I frame transport, windowing */
2445 if ((c->adaption != 1 && c->adaption != 2) || c->k)
2447 /* Check the MRU/MTU range looks sane */
2448 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8)
2452 if (c->encapsulation > 1) /* Basic, advanced, no I */
2454 if (c->initiator > 1)
2456 if (c->i == 0 || c->i > 2) /* UIH and UI only */
2459 * See what is needed for reconfiguration
2463 if (c->t1 != 0 && c->t1 != gsm->t1)
2465 if (c->t2 != 0 && c->t2 != gsm->t2)
2467 if (c->encapsulation != gsm->encoding)
2469 if (c->adaption != gsm->adaption)
2472 if (c->initiator != gsm->initiator)
2474 if (c->mru != gsm->mru)
2476 if (c->mtu != gsm->mtu)
2480 * Close down what is needed, restart and initiate the new
2484 if (need_close || need_restart) {
2485 gsm_dlci_begin_close(gsm->dlci[0]);
2486 /* This will timeout if the link is down due to N2 expiring */
2487 wait_event_interruptible(gsm->event,
2488 gsm->dlci[0]->state == DLCI_CLOSED);
2489 if (signal_pending(current))
2493 gsm_cleanup_mux(gsm);
2495 gsm->initiator = c->initiator;
2498 gsm->encoding = c->encapsulation;
2499 gsm->adaption = c->adaption;
2512 /* FIXME: We need to separate activation/deactivation from adding
2513 and removing from the mux array */
2515 gsm_activate_mux(gsm);
2516 if (gsm->initiator && need_close)
2517 gsm_dlci_begin_open(gsm->dlci[0]);
2521 static int gsmld_ioctl(struct tty_struct *tty, struct file *file,
2522 unsigned int cmd, unsigned long arg)
2524 struct gsm_config c;
2525 struct gsm_mux *gsm = tty->disc_data;
2528 case GSMIOC_GETCONF:
2529 memset(&c, 0, sizeof(c));
2530 c.adaption = gsm->adaption;
2531 c.encapsulation = gsm->encoding;
2532 c.initiator = gsm->initiator;
2535 c.t3 = 0; /* Not supported */
2537 if (gsm->ftype == UIH)
2541 pr_debug("Ftype %d i %d\n", gsm->ftype, c.i);
2545 if (copy_to_user((void *)arg, &c, sizeof(c)))
2548 case GSMIOC_SETCONF:
2549 if (copy_from_user(&c, (void *)arg, sizeof(c)))
2551 return gsmld_config(tty, gsm, &c);
2553 return n_tty_ioctl_helper(tty, file, cmd, arg);
2562 static int gsm_mux_net_open(struct net_device *net)
2564 pr_debug("%s called\n", __func__);
2565 netif_start_queue(net);
2569 static int gsm_mux_net_close(struct net_device *net)
2571 netif_stop_queue(net);
2575 static struct net_device_stats *gsm_mux_net_get_stats(struct net_device *net)
2577 return &((struct gsm_mux_net *)netdev_priv(net))->stats;
2579 static void dlci_net_free(struct gsm_dlci *dlci)
2585 dlci->adaption = dlci->prev_adaption;
2586 dlci->data = dlci->prev_data;
2587 free_netdev(dlci->net);
2590 static void net_free(struct kref *ref)
2592 struct gsm_mux_net *mux_net;
2593 struct gsm_dlci *dlci;
2595 mux_net = container_of(ref, struct gsm_mux_net, ref);
2596 dlci = mux_net->dlci;
2599 unregister_netdev(dlci->net);
2600 dlci_net_free(dlci);
2604 static inline void muxnet_get(struct gsm_mux_net *mux_net)
2606 kref_get(&mux_net->ref);
2609 static inline void muxnet_put(struct gsm_mux_net *mux_net)
2611 kref_put(&mux_net->ref, net_free);
2614 static int gsm_mux_net_start_xmit(struct sk_buff *skb,
2615 struct net_device *net)
2617 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
2618 struct gsm_dlci *dlci = mux_net->dlci;
2619 muxnet_get(mux_net);
2621 skb_queue_head(&dlci->skb_list, skb);
2622 STATS(net).tx_packets++;
2623 STATS(net).tx_bytes += skb->len;
2624 gsm_dlci_data_kick(dlci);
2625 /* And tell the kernel when the last transmit started. */
2626 net->trans_start = jiffies;
2627 muxnet_put(mux_net);
2628 return NETDEV_TX_OK;
2631 /* called when a packet did not ack after watchdogtimeout */
2632 static void gsm_mux_net_tx_timeout(struct net_device *net)
2634 /* Tell syslog we are hosed. */
2635 dev_dbg(&net->dev, "Tx timed out.\n");
2637 /* Update statistics */
2638 STATS(net).tx_errors++;
2641 static void gsm_mux_rx_netchar(struct gsm_dlci *dlci,
2642 unsigned char *in_buf, int size)
2644 struct net_device *net = dlci->net;
2645 struct sk_buff *skb;
2646 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
2647 muxnet_get(mux_net);
2649 /* Allocate an sk_buff */
2650 skb = dev_alloc_skb(size + NET_IP_ALIGN);
2652 /* We got no receive buffer. */
2653 STATS(net).rx_dropped++;
2654 muxnet_put(mux_net);
2657 skb_reserve(skb, NET_IP_ALIGN);
2658 memcpy(skb_put(skb, size), in_buf, size);
2661 skb->protocol = __constant_htons(ETH_P_IP);
2663 /* Ship it off to the kernel */
2666 /* update out statistics */
2667 STATS(net).rx_packets++;
2668 STATS(net).rx_bytes += size;
2669 muxnet_put(mux_net);
2673 int gsm_change_mtu(struct net_device *net, int new_mtu)
2675 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
2676 if ((new_mtu < 8) || (new_mtu > mux_net->dlci->gsm->mtu))
2682 static void gsm_mux_net_init(struct net_device *net)
2684 static const struct net_device_ops gsm_netdev_ops = {
2685 .ndo_open = gsm_mux_net_open,
2686 .ndo_stop = gsm_mux_net_close,
2687 .ndo_start_xmit = gsm_mux_net_start_xmit,
2688 .ndo_tx_timeout = gsm_mux_net_tx_timeout,
2689 .ndo_get_stats = gsm_mux_net_get_stats,
2690 .ndo_change_mtu = gsm_change_mtu,
2693 net->netdev_ops = &gsm_netdev_ops;
2695 /* fill in the other fields */
2696 net->watchdog_timeo = GSM_NET_TX_TIMEOUT;
2697 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
2698 net->type = ARPHRD_NONE;
2699 net->tx_queue_len = 10;
2703 /* caller holds the dlci mutex */
2704 static void gsm_destroy_network(struct gsm_dlci *dlci)
2706 struct gsm_mux_net *mux_net;
2708 pr_debug("destroy network interface");
2711 mux_net = (struct gsm_mux_net *)netdev_priv(dlci->net);
2712 muxnet_put(mux_net);
2716 /* caller holds the dlci mutex */
2717 static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
2721 struct net_device *net;
2722 struct gsm_mux_net *mux_net;
2724 if (!capable(CAP_NET_ADMIN))
2727 /* Already in a non tty mode */
2728 if (dlci->adaption > 2)
2731 if (nc->protocol != htons(ETH_P_IP))
2732 return -EPROTONOSUPPORT;
2734 if (nc->adaption != 3 && nc->adaption != 4)
2735 return -EPROTONOSUPPORT;
2737 pr_debug("create network interface");
2740 if (nc->if_name[0] != '\0')
2741 netname = nc->if_name;
2742 net = alloc_netdev(sizeof(struct gsm_mux_net),
2746 pr_err("alloc_netdev failed");
2749 net->mtu = dlci->gsm->mtu;
2750 mux_net = (struct gsm_mux_net *)netdev_priv(net);
2751 mux_net->dlci = dlci;
2752 kref_init(&mux_net->ref);
2753 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */
2755 /* reconfigure dlci for network */
2756 dlci->prev_adaption = dlci->adaption;
2757 dlci->prev_data = dlci->data;
2758 dlci->adaption = nc->adaption;
2759 dlci->data = gsm_mux_rx_netchar;
2762 pr_debug("register netdev");
2763 retval = register_netdev(net);
2765 pr_err("network register fail %d\n", retval);
2766 dlci_net_free(dlci);
2769 return net->ifindex; /* return network index */
2772 /* Line discipline for real tty */
2773 struct tty_ldisc_ops tty_ldisc_packet = {
2774 .owner = THIS_MODULE,
2775 .magic = TTY_LDISC_MAGIC,
2778 .close = gsmld_close,
2779 .flush_buffer = gsmld_flush_buffer,
2780 .chars_in_buffer = gsmld_chars_in_buffer,
2782 .write = gsmld_write,
2783 .ioctl = gsmld_ioctl,
2785 .receive_buf = gsmld_receive_buf,
2786 .write_wakeup = gsmld_write_wakeup
2795 static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk)
2798 struct gsm_control *ctrl;
2804 modembits[0] = len << 1 | EA; /* Data bytes */
2805 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */
2806 modembits[2] = gsm_encode_modem(dlci) << 1 | EA;
2808 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */
2809 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1);
2812 return gsm_control_wait(dlci->gsm, ctrl);
2815 static int gsm_carrier_raised(struct tty_port *port)
2817 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2818 /* Not yet open so no carrier info */
2819 if (dlci->state != DLCI_OPEN)
2823 return dlci->modem_rx & TIOCM_CD;
2826 static void gsm_dtr_rts(struct tty_port *port, int onoff)
2828 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2829 unsigned int modem_tx = dlci->modem_tx;
2831 modem_tx |= TIOCM_DTR | TIOCM_RTS;
2833 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
2834 if (modem_tx != dlci->modem_tx) {
2835 dlci->modem_tx = modem_tx;
2836 gsmtty_modem_update(dlci, 0);
2840 static const struct tty_port_operations gsm_port_ops = {
2841 .carrier_raised = gsm_carrier_raised,
2842 .dtr_rts = gsm_dtr_rts,
2846 static int gsmtty_open(struct tty_struct *tty, struct file *filp)
2848 struct gsm_mux *gsm;
2849 struct gsm_dlci *dlci;
2850 struct tty_port *port;
2851 unsigned int line = tty->index;
2852 unsigned int mux = line >> 6;
2858 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
2859 if (gsm_mux[mux] == NULL)
2861 if (line == 0 || line > 61) /* 62/63 reserved */
2866 dlci = gsm->dlci[line];
2868 dlci = gsm_dlci_alloc(gsm, line);
2873 tty->driver_data = dlci;
2875 dlci_get(dlci->gsm->dlci[0]);
2877 tty_port_tty_set(port, tty);
2880 /* We could in theory open and close before we wait - eg if we get
2881 a DM straight back. This is ok as that will have caused a hangup */
2882 set_bit(ASYNCB_INITIALIZED, &port->flags);
2883 /* Start sending off SABM messages */
2884 gsm_dlci_begin_open(dlci);
2885 /* And wait for virtual carrier */
2886 return tty_port_block_til_ready(port, tty, filp);
2889 static void gsmtty_close(struct tty_struct *tty, struct file *filp)
2891 struct gsm_dlci *dlci = tty->driver_data;
2892 struct gsm_mux *gsm;
2896 mutex_lock(&dlci->mutex);
2897 gsm_destroy_network(dlci);
2898 mutex_unlock(&dlci->mutex);
2900 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
2902 gsm_dlci_begin_close(dlci);
2903 tty_port_close_end(&dlci->port, tty);
2904 tty_port_tty_set(&dlci->port, NULL);
2907 dlci_put(gsm->dlci[0]);
2911 static void gsmtty_hangup(struct tty_struct *tty)
2913 struct gsm_dlci *dlci = tty->driver_data;
2914 tty_port_hangup(&dlci->port);
2915 gsm_dlci_begin_close(dlci);
2918 static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf,
2921 struct gsm_dlci *dlci = tty->driver_data;
2922 /* Stuff the bytes into the fifo queue */
2923 int sent = kfifo_in_locked(dlci->fifo, buf, len, &dlci->lock);
2924 /* Need to kick the channel */
2925 gsm_dlci_data_kick(dlci);
2929 static int gsmtty_write_room(struct tty_struct *tty)
2931 struct gsm_dlci *dlci = tty->driver_data;
2932 return TX_SIZE - kfifo_len(dlci->fifo);
2935 static int gsmtty_chars_in_buffer(struct tty_struct *tty)
2937 struct gsm_dlci *dlci = tty->driver_data;
2938 return kfifo_len(dlci->fifo);
2941 static void gsmtty_flush_buffer(struct tty_struct *tty)
2943 struct gsm_dlci *dlci = tty->driver_data;
2944 /* Caution needed: If we implement reliable transport classes
2945 then the data being transmitted can't simply be junked once
2946 it has first hit the stack. Until then we can just blow it
2948 kfifo_reset(dlci->fifo);
2949 /* Need to unhook this DLCI from the transmit queue logic */
2952 static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
2954 /* The FIFO handles the queue so the kernel will do the right
2955 thing waiting on chars_in_buffer before calling us. No work
2959 static int gsmtty_tiocmget(struct tty_struct *tty)
2961 struct gsm_dlci *dlci = tty->driver_data;
2962 return dlci->modem_rx;
2965 static int gsmtty_tiocmset(struct tty_struct *tty,
2966 unsigned int set, unsigned int clear)
2968 struct gsm_dlci *dlci = tty->driver_data;
2969 unsigned int modem_tx = dlci->modem_tx;
2974 if (modem_tx != dlci->modem_tx) {
2975 dlci->modem_tx = modem_tx;
2976 return gsmtty_modem_update(dlci, 0);
2982 static int gsmtty_ioctl(struct tty_struct *tty,
2983 unsigned int cmd, unsigned long arg)
2985 struct gsm_dlci *dlci = tty->driver_data;
2986 struct gsm_netconfig nc;
2990 case GSMIOC_ENABLE_NET:
2991 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc)))
2993 nc.if_name[IFNAMSIZ-1] = '\0';
2994 /* return net interface index or error code */
2995 mutex_lock(&dlci->mutex);
2996 index = gsm_create_network(dlci, &nc);
2997 mutex_unlock(&dlci->mutex);
2998 if (copy_to_user((void __user *)arg, &nc, sizeof(nc)))
3001 case GSMIOC_DISABLE_NET:
3002 if (!capable(CAP_NET_ADMIN))
3004 mutex_lock(&dlci->mutex);
3005 gsm_destroy_network(dlci);
3006 mutex_unlock(&dlci->mutex);
3009 return -ENOIOCTLCMD;
3013 static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old)
3015 /* For the moment its fixed. In actual fact the speed information
3016 for the virtual channel can be propogated in both directions by
3017 the RPN control message. This however rapidly gets nasty as we
3018 then have to remap modem signals each way according to whether
3019 our virtual cable is null modem etc .. */
3020 tty_termios_copy_hw(tty->termios, old);
3023 static void gsmtty_throttle(struct tty_struct *tty)
3025 struct gsm_dlci *dlci = tty->driver_data;
3026 if (tty->termios->c_cflag & CRTSCTS)
3027 dlci->modem_tx &= ~TIOCM_DTR;
3028 dlci->throttled = 1;
3029 /* Send an MSC with DTR cleared */
3030 gsmtty_modem_update(dlci, 0);
3033 static void gsmtty_unthrottle(struct tty_struct *tty)
3035 struct gsm_dlci *dlci = tty->driver_data;
3036 if (tty->termios->c_cflag & CRTSCTS)
3037 dlci->modem_tx |= TIOCM_DTR;
3038 dlci->throttled = 0;
3039 /* Send an MSC with DTR set */
3040 gsmtty_modem_update(dlci, 0);
3043 static int gsmtty_break_ctl(struct tty_struct *tty, int state)
3045 struct gsm_dlci *dlci = tty->driver_data;
3046 int encode = 0; /* Off */
3048 if (state == -1) /* "On indefinitely" - we can't encode this
3051 else if (state > 0) {
3052 encode = state / 200; /* mS to encoding */
3054 encode = 0x0F; /* Best effort */
3056 return gsmtty_modem_update(dlci, encode);
3060 /* Virtual ttys for the demux */
3061 static const struct tty_operations gsmtty_ops = {
3062 .open = gsmtty_open,
3063 .close = gsmtty_close,
3064 .write = gsmtty_write,
3065 .write_room = gsmtty_write_room,
3066 .chars_in_buffer = gsmtty_chars_in_buffer,
3067 .flush_buffer = gsmtty_flush_buffer,
3068 .ioctl = gsmtty_ioctl,
3069 .throttle = gsmtty_throttle,
3070 .unthrottle = gsmtty_unthrottle,
3071 .set_termios = gsmtty_set_termios,
3072 .hangup = gsmtty_hangup,
3073 .wait_until_sent = gsmtty_wait_until_sent,
3074 .tiocmget = gsmtty_tiocmget,
3075 .tiocmset = gsmtty_tiocmset,
3076 .break_ctl = gsmtty_break_ctl,
3081 static int __init gsm_init(void)
3083 /* Fill in our line protocol discipline, and register it */
3084 int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet);
3086 pr_err("n_gsm: can't register line discipline (err = %d)\n",
3091 gsm_tty_driver = alloc_tty_driver(256);
3092 if (!gsm_tty_driver) {
3093 tty_unregister_ldisc(N_GSM0710);
3094 pr_err("gsm_init: tty allocation failed.\n");
3097 gsm_tty_driver->owner = THIS_MODULE;
3098 gsm_tty_driver->driver_name = "gsmtty";
3099 gsm_tty_driver->name = "gsmtty";
3100 gsm_tty_driver->major = 0; /* Dynamic */
3101 gsm_tty_driver->minor_start = 0;
3102 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
3103 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
3104 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV
3105 | TTY_DRIVER_HARDWARE_BREAK;
3106 gsm_tty_driver->init_termios = tty_std_termios;
3108 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
3109 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
3111 spin_lock_init(&gsm_mux_lock);
3113 if (tty_register_driver(gsm_tty_driver)) {
3114 put_tty_driver(gsm_tty_driver);
3115 tty_unregister_ldisc(N_GSM0710);
3116 pr_err("gsm_init: tty registration failed.\n");
3119 pr_debug("gsm_init: loaded as %d,%d.\n",
3120 gsm_tty_driver->major, gsm_tty_driver->minor_start);
3124 static void __exit gsm_exit(void)
3126 int status = tty_unregister_ldisc(N_GSM0710);
3128 pr_err("n_gsm: can't unregister line discipline (err = %d)\n",
3130 tty_unregister_driver(gsm_tty_driver);
3131 put_tty_driver(gsm_tty_driver);
3134 module_init(gsm_init);
3135 module_exit(gsm_exit);
3138 MODULE_LICENSE("GPL");
3139 MODULE_ALIAS_LDISC(N_GSM0710);