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 gsm_msg *next;
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 */
137 struct kref ref; /* freed from port or mux close */
141 spinlock_t lock; /* Protects the internal state */
142 struct timer_list t1; /* Retransmit timer for SABM and UA */
144 /* Uplink tty if active */
145 struct tty_port port; /* The tty bound to this DLCI if there is one */
146 struct kfifo *fifo; /* Queue fifo for the DLCI */
147 struct kfifo _fifo; /* For new fifo API porting only */
148 int adaption; /* Adaption layer in use */
150 u32 modem_rx; /* Our incoming virtual modem lines */
151 u32 modem_tx; /* Our outgoing modem lines */
152 int dead; /* Refuse re-open */
154 int throttled; /* Private copy of throttle state */
155 int constipated; /* Throttle status for outgoing */
157 struct sk_buff *skb; /* Frame being sent */
158 struct sk_buff_head skb_list; /* Queued frames */
159 /* Data handling callback */
160 void (*data)(struct gsm_dlci *dlci, u8 *data, int len);
161 void (*prev_data)(struct gsm_dlci *dlci, u8 *data, int len);
162 struct net_device *net; /* network interface, if created */
165 /* DLCI 0, 62/63 are special or reseved see gsmtty_open */
170 * DLCI 0 is used to pass control blocks out of band of the data
171 * flow (and with a higher link priority). One command can be outstanding
172 * at a time and we use this structure to manage them. They are created
173 * and destroyed by the user context, and updated by the receive paths
178 u8 cmd; /* Command we are issuing */
179 u8 *data; /* Data for the command in case we retransmit */
180 int len; /* Length of block for retransmission */
181 int done; /* Done flag */
182 int error; /* Error if any */
186 * Each GSM mux we have is represented by this structure. If we are
187 * operating as an ldisc then we use this structure as our ldisc
188 * state. We need to sort out lifetimes and locking with respect
189 * to the gsm mux array. For now we don't free DLCI objects that
190 * have been instantiated until the mux itself is terminated.
192 * To consider further: tty open versus mux shutdown.
196 struct tty_struct *tty; /* The tty our ldisc is bound to */
201 /* Events on the GSM channel */
202 wait_queue_head_t event;
204 /* Bits for GSM mode decoding */
211 #define GSM_ADDRESS 2
212 #define GSM_CONTROL 3
216 #define GSM_OVERRUN 7
221 unsigned int address;
228 u8 *txframe; /* TX framing buffer */
230 /* Methods for the receiver side */
231 void (*receive)(struct gsm_mux *gsm, u8 ch);
232 void (*error)(struct gsm_mux *gsm, u8 ch, u8 flag);
233 /* And transmit side */
234 int (*output)(struct gsm_mux *mux, u8 *data, int len);
239 int initiator; /* Did we initiate connection */
240 int dead; /* Has the mux been shut down */
241 struct gsm_dlci *dlci[NUM_DLCI];
242 int constipated; /* Asked by remote to shut up */
245 unsigned int tx_bytes; /* TX data outstanding */
246 #define TX_THRESH_HI 8192
247 #define TX_THRESH_LO 2048
248 struct gsm_msg *tx_head; /* Pending data packets */
249 struct gsm_msg *tx_tail;
251 /* Control messages */
252 struct timer_list t2_timer; /* Retransmit timer for commands */
253 int cretries; /* Command retry counter */
254 struct gsm_control *pending_cmd;/* Our current pending command */
255 spinlock_t control_lock; /* Protects the pending command */
258 int adaption; /* 1 or 2 supported */
259 u8 ftype; /* UI or UIH */
260 int t1, t2; /* Timers in 1/100th of a sec */
261 int n2; /* Retry count */
263 /* Statistics (not currently exposed) */
264 unsigned long bad_fcs;
265 unsigned long malformed;
266 unsigned long io_error;
267 unsigned long bad_size;
268 unsigned long unsupported;
273 * Mux objects - needed so that we can translate a tty index into the
274 * relevant mux and DLCI.
277 #define MAX_MUX 4 /* 256 minors */
278 static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */
279 static spinlock_t gsm_mux_lock;
281 static struct tty_driver *gsm_tty_driver;
284 * This section of the driver logic implements the GSM encodings
285 * both the basic and the 'advanced'. Reliable transport is not
293 /* I is special: the rest are ..*/
304 /* Channel commands */
306 #define CMD_TEST 0x11
309 #define CMD_FCOFF 0x31
312 #define CMD_FCON 0x51
317 /* Virtual modem bits */
324 #define GSM0_SOF 0xF9
325 #define GSM1_SOF 0x7E
326 #define GSM1_ESCAPE 0x7D
327 #define GSM1_ESCAPE_BITS 0x20
331 static const struct tty_port_operations gsm_port_ops;
334 * CRC table for GSM 0710
337 static const u8 gsm_fcs8[256] = {
338 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75,
339 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B,
340 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69,
341 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67,
342 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D,
343 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43,
344 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51,
345 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F,
346 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05,
347 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B,
348 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19,
349 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17,
350 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D,
351 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33,
352 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21,
353 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F,
354 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95,
355 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B,
356 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89,
357 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87,
358 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD,
359 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3,
360 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1,
361 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF,
362 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5,
363 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB,
364 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9,
365 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7,
366 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD,
367 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3,
368 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1,
369 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF
372 #define INIT_FCS 0xFF
373 #define GOOD_FCS 0xCF
376 * gsm_fcs_add - update FCS
380 * Update the FCS to include c. Uses the algorithm in the specification
384 static inline u8 gsm_fcs_add(u8 fcs, u8 c)
386 return gsm_fcs8[fcs ^ c];
390 * gsm_fcs_add_block - update FCS for a block
393 * @len: length of buffer
395 * Update the FCS to include c. Uses the algorithm in the specification
399 static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len)
402 fcs = gsm_fcs8[fcs ^ *c++];
407 * gsm_read_ea - read a byte into an EA
408 * @val: variable holding value
409 * c: byte going into the EA
411 * Processes one byte of an EA. Updates the passed variable
412 * and returns 1 if the EA is now completely read
415 static int gsm_read_ea(unsigned int *val, u8 c)
417 /* Add the next 7 bits into the value */
420 /* Was this the last byte of the EA 1 = yes*/
425 * gsm_encode_modem - encode modem data bits
426 * @dlci: DLCI to encode from
428 * Returns the correct GSM encoded modem status bits (6 bit field) for
429 * the current status of the DLCI and attached tty object
432 static u8 gsm_encode_modem(const struct gsm_dlci *dlci)
435 /* FC is true flow control not modem bits */
438 if (dlci->modem_tx & TIOCM_DTR)
439 modembits |= MDM_RTC;
440 if (dlci->modem_tx & TIOCM_RTS)
441 modembits |= MDM_RTR;
442 if (dlci->modem_tx & TIOCM_RI)
444 if (dlci->modem_tx & TIOCM_CD)
450 * gsm_print_packet - display a frame for debug
451 * @hdr: header to print before decode
452 * @addr: address EA from the frame
453 * @cr: C/R bit from the frame
454 * @control: control including PF bit
455 * @data: following data bytes
456 * @dlen: length of data
458 * Displays a packet in human readable format for debugging purposes. The
459 * style is based on amateur radio LAP-B dump display.
462 static void gsm_print_packet(const char *hdr, int addr, int cr,
463 u8 control, const u8 *data, int dlen)
468 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]);
470 switch (control & ~PF) {
490 if (!(control & 0x01)) {
491 pr_cont("I N(S)%d N(R)%d",
492 (control & 0x0E) >> 1, (control & 0xE) >> 5);
493 } else switch (control & 0x0F) {
495 pr_cont("RR(%d)", (control & 0xE0) >> 5);
498 pr_cont("RNR(%d)", (control & 0xE0) >> 5);
501 pr_cont("REJ(%d)", (control & 0xE0) >> 5);
504 pr_cont("[%02X]", control);
520 pr_cont("%02X ", *data++);
529 * Link level transmission side
533 * gsm_stuff_packet - bytestuff a packet
536 * @len: length of input
538 * Expand a buffer by bytestuffing it. The worst case size change
539 * is doubling and the caller is responsible for handing out
540 * suitable sized buffers.
543 static int gsm_stuff_frame(const u8 *input, u8 *output, int len)
547 if (*input == GSM1_SOF || *input == GSM1_ESCAPE
548 || *input == XON || *input == XOFF) {
549 *output++ = GSM1_ESCAPE;
550 *output++ = *input++ ^ GSM1_ESCAPE_BITS;
553 *output++ = *input++;
560 * gsm_send - send a control frame
562 * @addr: address for control frame
563 * @cr: command/response bit
564 * @control: control byte including PF bit
566 * Format up and transmit a control frame. These do not go via the
567 * queueing logic as they should be transmitted ahead of data when
570 * FIXME: Lock versus data TX path
573 static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control)
579 switch (gsm->encoding) {
582 cbuf[1] = (addr << 2) | (cr << 1) | EA;
584 cbuf[3] = EA; /* Length of data = 0 */
585 cbuf[4] = 0xFF - gsm_fcs_add_block(INIT_FCS, cbuf + 1, 3);
591 /* Control frame + packing (but not frame stuffing) in mode 1 */
592 ibuf[0] = (addr << 2) | (cr << 1) | EA;
594 ibuf[2] = 0xFF - gsm_fcs_add_block(INIT_FCS, ibuf, 2);
595 /* Stuffing may double the size worst case */
596 len = gsm_stuff_frame(ibuf, cbuf + 1, 3);
597 /* Now add the SOF markers */
599 cbuf[len + 1] = GSM1_SOF;
600 /* FIXME: we can omit the lead one in many cases */
607 gsm->output(gsm, cbuf, len);
608 gsm_print_packet("-->", addr, cr, control, NULL, 0);
612 * gsm_response - send a control response
614 * @addr: address for control frame
615 * @control: control byte including PF bit
617 * Format up and transmit a link level response frame.
620 static inline void gsm_response(struct gsm_mux *gsm, int addr, int control)
622 gsm_send(gsm, addr, 0, control);
626 * gsm_command - send a control command
628 * @addr: address for control frame
629 * @control: control byte including PF bit
631 * Format up and transmit a link level command frame.
634 static inline void gsm_command(struct gsm_mux *gsm, int addr, int control)
636 gsm_send(gsm, addr, 1, control);
639 /* Data transmission */
641 #define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */
644 * gsm_data_alloc - allocate data frame
646 * @addr: DLCI address
647 * @len: length excluding header and FCS
648 * @ctrl: control byte
650 * Allocate a new data buffer for sending frames with data. Space is left
651 * at the front for header bytes but that is treated as an implementation
652 * detail and not for the high level code to use
655 static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
658 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN,
662 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */
671 * gsm_data_kick - poke the queue
674 * The tty device has called us to indicate that room has appeared in
675 * the transmit queue. Ram more data into the pipe if we have any
676 * If we have been flow-stopped by a CMD_FCOFF, then we can only
677 * send messages on DLCI0 until CMD_FCON
679 * FIXME: lock against link layer control transmissions
682 static void gsm_data_kick(struct gsm_mux *gsm)
684 struct gsm_msg *msg = gsm->tx_head;
685 struct gsm_msg *free_msg;
690 if (gsm->constipated && msg->addr) {
694 if (gsm->dlci[msg->addr]->constipated) {
698 if (gsm->encoding != 0) {
699 gsm->txframe[0] = GSM1_SOF;
700 len = gsm_stuff_frame(msg->data,
701 gsm->txframe + 1, msg->len);
702 gsm->txframe[len + 1] = GSM1_SOF;
705 gsm->txframe[0] = GSM0_SOF;
706 memcpy(gsm->txframe + 1 , msg->data, msg->len);
707 gsm->txframe[msg->len + 1] = GSM0_SOF;
712 print_hex_dump_bytes("gsm_data_kick: ",
716 if (gsm->output(gsm, gsm->txframe + skip_sof,
719 /* FIXME: Can eliminate one SOF in many more cases */
720 gsm->tx_bytes -= msg->len;
721 /* For a burst of frames skip the extra SOF within the
725 if (gsm->tx_head == msg)
726 gsm->tx_head = msg->next;
736 * __gsm_data_queue - queue a UI or UIH frame
737 * @dlci: DLCI sending the data
738 * @msg: message queued
740 * Add data to the transmit queue and try and get stuff moving
741 * out of the mux tty if not already doing so. The Caller must hold
745 static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
747 struct gsm_mux *gsm = dlci->gsm;
749 u8 *fcs = dp + msg->len;
751 WARN_ONCE(dlci->constipated, "%s: queueing from a constipated DLCI",
753 /* Fill in the header */
754 if (gsm->encoding == 0) {
756 *--dp = (msg->len << 1) | EA;
758 *--dp = (msg->len >> 7); /* bits 7 - 15 */
759 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */
765 *--dp = (msg->addr << 2) | 2 | EA;
767 *--dp = (msg->addr << 2) | EA;
768 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp);
769 /* Ugly protocol layering violation */
770 if (msg->ctrl == UI || msg->ctrl == (UI|PF))
771 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len);
774 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl,
775 msg->data, msg->len);
777 /* Move the header back and adjust the length, also allow for the FCS
778 now tacked on the end */
779 msg->len += (msg->data - dp) + 1;
782 /* Add to the actual output queue */
784 gsm->tx_tail->next = msg;
788 gsm->tx_bytes += msg->len;
793 * gsm_data_queue - queue a UI or UIH frame
794 * @dlci: DLCI sending the data
795 * @msg: message queued
797 * Add data to the transmit queue and try and get stuff moving
798 * out of the mux tty if not already doing so. Take the
799 * the gsm tx lock and dlci lock.
802 static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
805 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
806 __gsm_data_queue(dlci, msg);
807 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
811 * gsm_dlci_data_output - try and push data out of a DLCI
813 * @dlci: the DLCI to pull data from
815 * Pull data from a DLCI and send it into the transmit queue if there
816 * is data. Keep to the MRU of the mux. This path handles the usual tty
817 * interface which is a byte stream with optional modem data.
819 * Caller must hold the tx_lock of the mux.
822 static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci)
826 int len, total_size, size;
827 int h = dlci->adaption - 1;
831 len = kfifo_len(dlci->fifo);
835 /* MTU/MRU count only the data bits */
841 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
842 /* FIXME: need a timer or something to kick this so it can't
843 get stuck with no work outstanding and no buffer free */
847 switch (dlci->adaption) {
848 case 1: /* Unstructured */
850 case 2: /* Unstructed with modem bits. Always one byte as we never
851 send inline break data */
852 *dp++ = gsm_encode_modem(dlci);
855 WARN_ON(kfifo_out_locked(dlci->fifo, dp , len, &dlci->lock) != len);
856 __gsm_data_queue(dlci, msg);
859 /* Bytes of data we used up */
864 * gsm_dlci_data_output_framed - try and push data out of a DLCI
866 * @dlci: the DLCI to pull data from
868 * Pull data from a DLCI and send it into the transmit queue if there
869 * is data. Keep to the MRU of the mux. This path handles framed data
870 * queued as skbuffs to the DLCI.
872 * Caller must hold the tx_lock of the mux.
875 static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
876 struct gsm_dlci *dlci)
881 int last = 0, first = 0;
884 /* One byte per frame is used for B/F flags */
885 if (dlci->adaption == 4)
888 /* dlci->skb is locked by tx_lock */
889 if (dlci->skb == NULL) {
890 dlci->skb = skb_dequeue(&dlci->skb_list);
891 if (dlci->skb == NULL)
895 len = dlci->skb->len + overhead;
897 /* MTU/MRU count only the data bits */
898 if (len > gsm->mtu) {
899 if (dlci->adaption == 3) {
900 /* Over long frame, bin it */
901 kfree_skb(dlci->skb);
909 size = len + overhead;
910 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
912 /* FIXME: need a timer or something to kick this so it can't
913 get stuck with no work outstanding and no buffer free */
918 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */
919 /* Flag byte to carry the start/end info */
920 *dp++ = last << 7 | first << 6 | 1; /* EA */
923 memcpy(dp, dlci->skb->data, len);
924 skb_pull(dlci->skb, len);
925 __gsm_data_queue(dlci, msg);
927 kfree_skb(dlci->skb);
934 * gsm_dlci_data_sweep - look for data to send
937 * Sweep the GSM mux channels in priority order looking for ones with
938 * data to send. We could do with optimising this scan a bit. We aim
939 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit
940 * TX_THRESH_LO we get called again
942 * FIXME: We should round robin between groups and in theory you can
943 * renegotiate DLCI priorities with optional stuff. Needs optimising.
946 static void gsm_dlci_data_sweep(struct gsm_mux *gsm)
949 /* Priority ordering: We should do priority with RR of the groups */
952 while (i < NUM_DLCI) {
953 struct gsm_dlci *dlci;
955 if (gsm->tx_bytes > TX_THRESH_HI)
958 if (dlci == NULL || dlci->constipated) {
959 if (dlci && (debug & 0x20))
960 pr_info("%s: DLCI %d is constipated",
965 if (dlci->adaption < 3 && !dlci->net)
966 len = gsm_dlci_data_output(gsm, dlci);
968 len = gsm_dlci_data_output_framed(gsm, dlci);
971 /* DLCI empty - try the next */
978 * gsm_dlci_data_kick - transmit if possible
979 * @dlci: DLCI to kick
981 * Transmit data from this DLCI if the queue is empty. We can't rely on
982 * a tty wakeup except when we filled the pipe so we need to fire off
983 * new data ourselves in other cases.
986 static void gsm_dlci_data_kick(struct gsm_dlci *dlci)
991 if (dlci->constipated) {
993 pr_info("%s: DLCI %d is constipated",
994 __func__, dlci->addr);
998 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
999 /* If we have nothing running then we need to fire up */
1000 sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO);
1001 if (dlci->gsm->tx_bytes == 0) {
1003 gsm_dlci_data_output_framed(dlci->gsm, dlci);
1005 gsm_dlci_data_output(dlci->gsm, dlci);
1008 gsm_dlci_data_sweep(dlci->gsm);
1009 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
1013 * Control message processing
1018 * gsm_control_reply - send a response frame to a control
1020 * @cmd: the command to use
1021 * @data: data to follow encoded info
1022 * @dlen: length of data
1024 * Encode up and queue a UI/UIH frame containing our response.
1027 static void gsm_control_reply(struct gsm_mux *gsm, int cmd, u8 *data,
1030 struct gsm_msg *msg;
1031 msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype);
1034 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */
1035 msg->data[1] = (dlen << 1) | EA;
1036 memcpy(msg->data + 2, data, dlen);
1037 gsm_data_queue(gsm->dlci[0], msg);
1041 * gsm_process_modem - process received modem status
1042 * @tty: virtual tty bound to the DLCI
1043 * @dlci: DLCI to affect
1044 * @modem: modem bits (full EA)
1046 * Used when a modem control message or line state inline in adaption
1047 * layer 2 is processed. Sort out the local modem state and throttles
1050 static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
1051 u32 modem, int clen)
1057 /* The modem status command can either contain one octet (v.24 signals)
1058 or two octets (v.24 signals + break signals). The length field will
1059 either be 2 or 3 respectively. This is specified in section
1060 5.4.6.3.7 of the 27.010 mux spec. */
1063 modem = modem & 0x7f;
1066 modem = (modem >> 7) & 0x7f;
1069 /* Flow control/ready to communicate */
1070 fc = (modem & MDM_FC) || !(modem & MDM_RTR);
1071 if (fc && !dlci->constipated) {
1073 pr_info("%s: DLCI %d START constipated (tx_bytes=%d)",
1074 __func__, dlci->addr, dlci->gsm->tx_bytes);
1075 /* Need to throttle our output on this device */
1076 dlci->constipated = 1;
1077 } else if (!fc && dlci->constipated) {
1079 pr_info("%s: DLCI %d END constipated (tx_bytes=%d)",
1080 __func__, dlci->addr, dlci->gsm->tx_bytes);
1081 dlci->constipated = 0;
1082 gsm_dlci_data_kick(dlci);
1085 /* Map modem bits */
1086 if (modem & MDM_RTC)
1087 mlines |= TIOCM_DSR | TIOCM_DTR;
1088 if (modem & MDM_RTR)
1089 mlines |= TIOCM_RTS | TIOCM_CTS;
1095 /* Carrier drop -> hangup */
1097 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD))
1098 if (!(tty->termios->c_cflag & CLOCAL))
1101 tty_insert_flip_char(tty, 0, TTY_BREAK);
1103 dlci->modem_rx = mlines;
1107 * gsm_control_modem - modem status received
1109 * @data: data following command
1110 * @clen: command length
1112 * We have received a modem status control message. This is used by
1113 * the GSM mux protocol to pass virtual modem line status and optionally
1114 * to indicate break signals. Unpack it, convert to Linux representation
1115 * and if need be stuff a break message down the tty.
1118 static void gsm_control_modem(struct gsm_mux *gsm, u8 *data, int clen)
1120 unsigned int addr = 0;
1121 unsigned int modem = 0;
1122 struct gsm_dlci *dlci;
1125 struct tty_struct *tty;
1127 while (gsm_read_ea(&addr, *dp++) == 0) {
1132 /* Must be at least one byte following the EA */
1138 /* Closed port, or invalid ? */
1139 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1141 dlci = gsm->dlci[addr];
1143 while (gsm_read_ea(&modem, *dp++) == 0) {
1148 tty = tty_port_tty_get(&dlci->port);
1149 gsm_process_modem(tty, dlci, modem, clen);
1154 gsm_control_reply(gsm, CMD_MSC, data, clen);
1158 * gsm_control_rls - remote line status
1161 * @clen: data length
1163 * The modem sends us a two byte message on the control channel whenever
1164 * it wishes to send us an error state from the virtual link. Stuff
1165 * this into the uplink tty if present
1168 static void gsm_control_rls(struct gsm_mux *gsm, u8 *data, int clen)
1170 struct tty_struct *tty;
1171 unsigned int addr = 0 ;
1176 while (gsm_read_ea(&addr, *dp++) == 0) {
1181 /* Must be at least one byte following ea */
1186 /* Closed port, or invalid ? */
1187 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1191 if ((bits & 1) == 0)
1193 /* See if we have an uplink tty */
1194 tty = tty_port_tty_get(&gsm->dlci[addr]->port);
1198 tty_insert_flip_char(tty, 0, TTY_OVERRUN);
1200 tty_insert_flip_char(tty, 0, TTY_PARITY);
1202 tty_insert_flip_char(tty, 0, TTY_FRAME);
1203 tty_flip_buffer_push(tty);
1206 gsm_control_reply(gsm, CMD_RLS, data, clen);
1209 static void gsm_dlci_begin_close(struct gsm_dlci *dlci);
1212 * gsm_control_message - DLCI 0 control processing
1214 * @command: the command EA
1215 * @data: data beyond the command/length EAs
1218 * Input processor for control messages from the other end of the link.
1219 * Processes the incoming request and queues a response frame or an
1220 * NSC response if not supported
1223 static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
1229 struct gsm_dlci *dlci = gsm->dlci[0];
1230 /* Modem wishes to close down */
1234 gsm_dlci_begin_close(dlci);
1239 /* Modem wishes to test, reply with the data */
1240 gsm_control_reply(gsm, CMD_TEST, data, clen);
1243 /* Modem can accept data again */
1245 pr_info("%s: GSM END constipation", __func__);
1246 gsm->constipated = 0;
1247 gsm_control_reply(gsm, CMD_FCON, NULL, 0);
1248 /* Kick the link in case it is idling */
1252 /* Modem wants us to STFU */
1254 pr_info("%s: GSM START constipation", __func__);
1255 gsm->constipated = 1;
1256 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0);
1259 /* Out of band modem line change indicator for a DLCI */
1260 gsm_control_modem(gsm, data, clen);
1263 /* Out of band error reception for a DLCI */
1264 gsm_control_rls(gsm, data, clen);
1267 /* Modem wishes to enter power saving state */
1268 gsm_control_reply(gsm, CMD_PSC, NULL, 0);
1270 /* Optional unsupported commands */
1271 case CMD_PN: /* Parameter negotiation */
1272 case CMD_RPN: /* Remote port negotiation */
1273 case CMD_SNC: /* Service negotiation command */
1275 /* Reply to bad commands with an NSC */
1277 gsm_control_reply(gsm, CMD_NSC, buf, 1);
1283 * gsm_control_response - process a response to our control
1285 * @command: the command (response) EA
1286 * @data: data beyond the command/length EA
1289 * Process a response to an outstanding command. We only allow a single
1290 * control message in flight so this is fairly easy. All the clean up
1291 * is done by the caller, we just update the fields, flag it as done
1295 static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
1298 struct gsm_control *ctrl;
1299 unsigned long flags;
1301 spin_lock_irqsave(&gsm->control_lock, flags);
1303 ctrl = gsm->pending_cmd;
1304 /* Does the reply match our command */
1306 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) {
1307 /* Our command was replied to, kill the retry timer */
1308 del_timer(&gsm->t2_timer);
1309 gsm->pending_cmd = NULL;
1310 /* Rejected by the other end */
1311 if (command == CMD_NSC)
1312 ctrl->error = -EOPNOTSUPP;
1314 wake_up(&gsm->event);
1316 spin_unlock_irqrestore(&gsm->control_lock, flags);
1320 * gsm_control_transmit - send control packet
1322 * @ctrl: frame to send
1324 * Send out a pending control command (called under control lock)
1327 static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl)
1329 struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, gsm->ftype);
1332 msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */
1333 memcpy(msg->data + 1, ctrl->data, ctrl->len);
1334 gsm_data_queue(gsm->dlci[0], msg);
1338 * gsm_control_retransmit - retransmit a control frame
1339 * @data: pointer to our gsm object
1341 * Called off the T2 timer expiry in order to retransmit control frames
1342 * that have been lost in the system somewhere. The control_lock protects
1343 * us from colliding with another sender or a receive completion event.
1344 * In that situation the timer may still occur in a small window but
1345 * gsm->pending_cmd will be NULL and we just let the timer expire.
1348 static void gsm_control_retransmit(unsigned long data)
1350 struct gsm_mux *gsm = (struct gsm_mux *)data;
1351 struct gsm_control *ctrl;
1352 unsigned long flags;
1353 spin_lock_irqsave(&gsm->control_lock, flags);
1354 ctrl = gsm->pending_cmd;
1357 if (gsm->cretries == 0) {
1358 gsm->pending_cmd = NULL;
1359 ctrl->error = -ETIMEDOUT;
1361 spin_unlock_irqrestore(&gsm->control_lock, flags);
1362 wake_up(&gsm->event);
1365 gsm_control_transmit(gsm, ctrl);
1366 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1368 spin_unlock_irqrestore(&gsm->control_lock, flags);
1372 * gsm_control_send - send a control frame on DLCI 0
1373 * @gsm: the GSM channel
1374 * @command: command to send including CR bit
1375 * @data: bytes of data (must be kmalloced)
1376 * @len: length of the block to send
1378 * Queue and dispatch a control command. Only one command can be
1379 * active at a time. In theory more can be outstanding but the matching
1380 * gets really complicated so for now stick to one outstanding.
1383 static struct gsm_control *gsm_control_send(struct gsm_mux *gsm,
1384 unsigned int command, u8 *data, int clen)
1386 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control),
1388 unsigned long flags;
1392 wait_event(gsm->event, gsm->pending_cmd == NULL);
1393 spin_lock_irqsave(&gsm->control_lock, flags);
1394 if (gsm->pending_cmd != NULL) {
1395 spin_unlock_irqrestore(&gsm->control_lock, flags);
1398 ctrl->cmd = command;
1401 gsm->pending_cmd = ctrl;
1402 gsm->cretries = gsm->n2;
1403 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1404 gsm_control_transmit(gsm, ctrl);
1405 spin_unlock_irqrestore(&gsm->control_lock, flags);
1410 * gsm_control_wait - wait for a control to finish
1412 * @control: control we are waiting on
1414 * Waits for the control to complete or time out. Frees any used
1415 * resources and returns 0 for success, or an error if the remote
1416 * rejected or ignored the request.
1419 static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
1422 wait_event(gsm->event, control->done == 1);
1423 err = control->error;
1430 * DLCI level handling: Needs krefs
1434 * State transitions and timers
1438 * gsm_dlci_close - a DLCI has closed
1439 * @dlci: DLCI that closed
1441 * Perform processing when moving a DLCI into closed state. If there
1442 * is an attached tty this is hung up
1445 static void gsm_dlci_close(struct gsm_dlci *dlci)
1447 del_timer(&dlci->t1);
1449 pr_debug("DLCI %d goes closed.\n", dlci->addr);
1450 dlci->state = DLCI_CLOSED;
1451 if (dlci->addr != 0) {
1452 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1457 kfifo_reset(dlci->fifo);
1459 dlci->gsm->dead = 1;
1460 wake_up(&dlci->gsm->event);
1461 /* A DLCI 0 close is a MUX termination so we need to kick that
1462 back to userspace somehow */
1466 * gsm_dlci_open - a DLCI has opened
1467 * @dlci: DLCI that opened
1469 * Perform processing when moving a DLCI into open state.
1472 static void gsm_dlci_open(struct gsm_dlci *dlci)
1474 /* Note that SABM UA .. SABM UA first UA lost can mean that we go
1476 del_timer(&dlci->t1);
1477 /* This will let a tty open continue */
1478 dlci->state = DLCI_OPEN;
1480 pr_debug("DLCI %d goes open.\n", dlci->addr);
1481 wake_up(&dlci->gsm->event);
1485 * gsm_dlci_t1 - T1 timer expiry
1486 * @dlci: DLCI that opened
1488 * The T1 timer handles retransmits of control frames (essentially of
1489 * SABM and DISC). We resend the command until the retry count runs out
1490 * in which case an opening port goes back to closed and a closing port
1491 * is simply put into closed state (any further frames from the other
1492 * end will get a DM response)
1495 static void gsm_dlci_t1(unsigned long data)
1497 struct gsm_dlci *dlci = (struct gsm_dlci *)data;
1498 struct gsm_mux *gsm = dlci->gsm;
1500 switch (dlci->state) {
1503 if (dlci->retries) {
1504 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1505 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1507 gsm_dlci_close(dlci);
1511 if (dlci->retries) {
1512 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1513 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1515 gsm_dlci_close(dlci);
1521 * gsm_dlci_begin_open - start channel open procedure
1522 * @dlci: DLCI to open
1524 * Commence opening a DLCI from the Linux side. We issue SABM messages
1525 * to the modem which should then reply with a UA, at which point we
1526 * will move into open state. Opening is done asynchronously with retry
1527 * running off timers and the responses.
1530 static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
1532 struct gsm_mux *gsm = dlci->gsm;
1533 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING)
1535 dlci->retries = gsm->n2;
1536 dlci->state = DLCI_OPENING;
1537 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1538 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1542 * gsm_dlci_begin_close - start channel open procedure
1543 * @dlci: DLCI to open
1545 * Commence closing a DLCI from the Linux side. We issue DISC messages
1546 * to the modem which should then reply with a UA, at which point we
1547 * will move into closed state. Closing is done asynchronously with retry
1548 * off timers. We may also receive a DM reply from the other end which
1549 * indicates the channel was already closed.
1552 static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
1554 struct gsm_mux *gsm = dlci->gsm;
1555 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
1557 dlci->retries = gsm->n2;
1558 dlci->state = DLCI_CLOSING;
1559 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1560 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1564 * gsm_dlci_data - data arrived
1566 * @data: block of bytes received
1567 * @len: length of received block
1569 * A UI or UIH frame has arrived which contains data for a channel
1570 * other than the control channel. If the relevant virtual tty is
1571 * open we shovel the bits down it, if not we drop them.
1574 static void gsm_dlci_data(struct gsm_dlci *dlci, u8 *data, int clen)
1577 struct tty_port *port = &dlci->port;
1578 struct tty_struct *tty = tty_port_tty_get(port);
1579 unsigned int modem = 0;
1583 pr_debug("%d bytes for tty %p\n", len, tty);
1585 switch (dlci->adaption) {
1586 /* Unsupported types */
1587 /* Packetised interruptible data */
1590 /* Packetised uininterruptible voice/data */
1593 /* Asynchronous serial with line state in each frame */
1595 while (gsm_read_ea(&modem, *data++) == 0) {
1600 gsm_process_modem(tty, dlci, modem, clen);
1601 /* Line state will go via DLCI 0 controls only */
1604 tty_insert_flip_string(tty, data, len);
1605 tty_flip_buffer_push(tty);
1612 * gsm_dlci_control - data arrived on control channel
1614 * @data: block of bytes received
1615 * @len: length of received block
1617 * A UI or UIH frame has arrived which contains data for DLCI 0 the
1618 * control channel. This should contain a command EA followed by
1619 * control data bytes. The command EA contains a command/response bit
1620 * and we divide up the work accordingly.
1623 static void gsm_dlci_command(struct gsm_dlci *dlci, u8 *data, int len)
1625 /* See what command is involved */
1626 unsigned int command = 0;
1628 if (gsm_read_ea(&command, *data++) == 1) {
1631 /* FIXME: this is properly an EA */
1633 /* Malformed command ? */
1637 gsm_control_message(dlci->gsm, command,
1640 gsm_control_response(dlci->gsm, command,
1648 * Allocate/Free DLCI channels
1652 * gsm_dlci_alloc - allocate a DLCI
1654 * @addr: address of the DLCI
1656 * Allocate and install a new DLCI object into the GSM mux.
1658 * FIXME: review locking races
1661 static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
1663 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC);
1666 spin_lock_init(&dlci->lock);
1667 kref_init(&dlci->ref);
1668 mutex_init(&dlci->mutex);
1669 dlci->fifo = &dlci->_fifo;
1670 if (kfifo_alloc(&dlci->_fifo, 4096, GFP_KERNEL) < 0) {
1675 skb_queue_head_init(&dlci->skb_list);
1676 init_timer(&dlci->t1);
1677 dlci->t1.function = gsm_dlci_t1;
1678 dlci->t1.data = (unsigned long)dlci;
1679 tty_port_init(&dlci->port);
1680 dlci->port.ops = &gsm_port_ops;
1683 dlci->adaption = gsm->adaption;
1684 dlci->state = DLCI_CLOSED;
1686 dlci->data = gsm_dlci_data;
1688 dlci->data = gsm_dlci_command;
1689 gsm->dlci[addr] = dlci;
1694 * gsm_dlci_free - free DLCI
1695 * @dlci: DLCI to free
1701 static void gsm_dlci_free(struct kref *ref)
1703 struct gsm_dlci *dlci = container_of(ref, struct gsm_dlci, ref);
1705 del_timer_sync(&dlci->t1);
1706 dlci->gsm->dlci[dlci->addr] = NULL;
1707 kfifo_free(dlci->fifo);
1708 while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
1709 kfree_skb(dlci->skb);
1713 static inline void dlci_get(struct gsm_dlci *dlci)
1715 kref_get(&dlci->ref);
1718 static inline void dlci_put(struct gsm_dlci *dlci)
1720 kref_put(&dlci->ref, gsm_dlci_free);
1724 * gsm_dlci_release - release DLCI
1725 * @dlci: DLCI to destroy
1727 * Release a DLCI. Actual free is deferred until either
1728 * mux is closed or tty is closed - whichever is last.
1732 static void gsm_dlci_release(struct gsm_dlci *dlci)
1734 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1743 * LAPBish link layer logic
1747 * gsm_queue - a GSM frame is ready to process
1748 * @gsm: pointer to our gsm mux
1750 * At this point in time a frame has arrived and been demangled from
1751 * the line encoding. All the differences between the encodings have
1752 * been handled below us and the frame is unpacked into the structures.
1753 * The fcs holds the header FCS but any data FCS must be added here.
1756 static void gsm_queue(struct gsm_mux *gsm)
1758 struct gsm_dlci *dlci;
1761 /* We have to sneak a look at the packet body to do the FCS.
1762 A somewhat layering violation in the spec */
1764 if ((gsm->control & ~PF) == UI)
1765 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len);
1766 if (gsm->encoding == 0){
1767 /* WARNING: gsm->received_fcs is used for gsm->encoding = 0 only.
1768 In this case it contain the last piece of data
1769 required to generate final CRC */
1770 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs);
1772 if (gsm->fcs != GOOD_FCS) {
1775 pr_debug("BAD FCS %02x\n", gsm->fcs);
1778 address = gsm->address >> 1;
1779 if (address >= NUM_DLCI)
1782 cr = gsm->address & 1; /* C/R bit */
1784 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
1786 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */
1787 dlci = gsm->dlci[address];
1789 switch (gsm->control) {
1794 dlci = gsm_dlci_alloc(gsm, address);
1798 gsm_response(gsm, address, DM);
1800 gsm_response(gsm, address, UA);
1801 gsm_dlci_open(dlci);
1807 if (dlci == NULL || dlci->state == DLCI_CLOSED) {
1808 gsm_response(gsm, address, DM);
1811 /* Real close complete */
1812 gsm_response(gsm, address, UA);
1813 gsm_dlci_close(dlci);
1817 if (cr == 0 || dlci == NULL)
1819 switch (dlci->state) {
1821 gsm_dlci_close(dlci);
1824 gsm_dlci_open(dlci);
1828 case DM: /* DM can be valid unsolicited */
1834 gsm_dlci_close(dlci);
1844 if (dlci == NULL || dlci->state != DLCI_OPEN) {
1845 gsm_command(gsm, address, DM|PF);
1848 dlci->data(dlci, gsm->buf, gsm->len);
1861 * gsm0_receive - perform processing for non-transparency
1862 * @gsm: gsm data for this ldisc instance
1865 * Receive bytes in gsm mode 0
1868 static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
1872 switch (gsm->state) {
1873 case GSM_SEARCH: /* SOF marker */
1874 if (c == GSM0_SOF) {
1875 gsm->state = GSM_ADDRESS;
1878 gsm->fcs = INIT_FCS;
1881 case GSM_ADDRESS: /* Address EA */
1882 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1883 if (gsm_read_ea(&gsm->address, c))
1884 gsm->state = GSM_CONTROL;
1886 case GSM_CONTROL: /* Control Byte */
1887 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1889 gsm->state = GSM_LEN0;
1891 case GSM_LEN0: /* Length EA */
1892 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1893 if (gsm_read_ea(&gsm->len, c)) {
1894 if (gsm->len > gsm->mru) {
1896 gsm->state = GSM_SEARCH;
1901 gsm->state = GSM_FCS;
1903 gsm->state = GSM_DATA;
1906 gsm->state = GSM_LEN1;
1909 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1911 gsm->len |= len << 7;
1912 if (gsm->len > gsm->mru) {
1914 gsm->state = GSM_SEARCH;
1919 gsm->state = GSM_FCS;
1921 gsm->state = GSM_DATA;
1923 case GSM_DATA: /* Data */
1924 gsm->buf[gsm->count++] = c;
1925 if (gsm->count == gsm->len)
1926 gsm->state = GSM_FCS;
1928 case GSM_FCS: /* FCS follows the packet */
1929 gsm->received_fcs = c;
1931 gsm->state = GSM_SSOF;
1934 if (c == GSM0_SOF) {
1935 gsm->state = GSM_SEARCH;
1943 * gsm1_receive - perform processing for non-transparency
1944 * @gsm: gsm data for this ldisc instance
1947 * Receive bytes in mode 1 (Advanced option)
1950 static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
1952 if (c == GSM1_SOF) {
1953 /* EOF is only valid in frame if we have got to the data state
1954 and received at least one byte (the FCS) */
1955 if (gsm->state == GSM_DATA && gsm->count) {
1956 /* Extract the FCS */
1958 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
1959 gsm->len = gsm->count;
1961 gsm->state = GSM_START;
1964 /* Any partial frame was a runt so go back to start */
1965 if (gsm->state != GSM_START) {
1967 gsm->state = GSM_START;
1969 /* A SOF in GSM_START means we are still reading idling or
1974 if (c == GSM1_ESCAPE) {
1979 /* Only an unescaped SOF gets us out of GSM search */
1980 if (gsm->state == GSM_SEARCH)
1984 c ^= GSM1_ESCAPE_BITS;
1987 switch (gsm->state) {
1988 case GSM_START: /* First byte after SOF */
1990 gsm->state = GSM_ADDRESS;
1991 gsm->fcs = INIT_FCS;
1993 case GSM_ADDRESS: /* Address continuation */
1994 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1995 if (gsm_read_ea(&gsm->address, c))
1996 gsm->state = GSM_CONTROL;
1998 case GSM_CONTROL: /* Control Byte */
1999 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2002 gsm->state = GSM_DATA;
2004 case GSM_DATA: /* Data */
2005 if (gsm->count > gsm->mru) { /* Allow one for the FCS */
2006 gsm->state = GSM_OVERRUN;
2009 gsm->buf[gsm->count++] = c;
2011 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */
2017 * gsm_error - handle tty error
2019 * @data: byte received (may be invalid)
2020 * @flag: error received
2022 * Handle an error in the receipt of data for a frame. Currently we just
2023 * go back to hunting for a SOF.
2025 * FIXME: better diagnostics ?
2028 static void gsm_error(struct gsm_mux *gsm,
2029 unsigned char data, unsigned char flag)
2031 gsm->state = GSM_SEARCH;
2036 * gsm_cleanup_mux - generic GSM protocol cleanup
2039 * Clean up the bits of the mux which are the same for all framing
2040 * protocols. Remove the mux from the mux table, stop all the timers
2041 * and then shut down each device hanging up the channels as we go.
2044 void gsm_cleanup_mux(struct gsm_mux *gsm)
2047 struct gsm_dlci *dlci = gsm->dlci[0];
2048 struct gsm_msg *txq;
2049 struct gsm_control *gc;
2053 spin_lock(&gsm_mux_lock);
2054 for (i = 0; i < MAX_MUX; i++) {
2055 if (gsm_mux[i] == gsm) {
2060 spin_unlock(&gsm_mux_lock);
2061 WARN_ON(i == MAX_MUX);
2063 /* In theory disconnecting DLCI 0 is sufficient but for some
2064 modems this is apparently not the case. */
2066 gc = gsm_control_send(gsm, CMD_CLD, NULL, 0);
2068 gsm_control_wait(gsm, gc);
2070 del_timer_sync(&gsm->t2_timer);
2071 /* Now we are sure T2 has stopped */
2074 gsm_dlci_begin_close(dlci);
2075 wait_event_interruptible(gsm->event,
2076 dlci->state == DLCI_CLOSED);
2078 /* Free up any link layer users */
2079 for (i = 0; i < NUM_DLCI; i++)
2081 gsm_dlci_release(gsm->dlci[i]);
2082 /* Now wipe the queues */
2083 for (txq = gsm->tx_head; txq != NULL; txq = gsm->tx_head) {
2084 gsm->tx_head = txq->next;
2087 gsm->tx_tail = NULL;
2089 EXPORT_SYMBOL_GPL(gsm_cleanup_mux);
2092 * gsm_activate_mux - generic GSM setup
2095 * Set up the bits of the mux which are the same for all framing
2096 * protocols. Add the mux to the mux table so it can be opened and
2097 * finally kick off connecting to DLCI 0 on the modem.
2100 int gsm_activate_mux(struct gsm_mux *gsm)
2102 struct gsm_dlci *dlci;
2105 init_timer(&gsm->t2_timer);
2106 gsm->t2_timer.function = gsm_control_retransmit;
2107 gsm->t2_timer.data = (unsigned long)gsm;
2108 init_waitqueue_head(&gsm->event);
2109 spin_lock_init(&gsm->control_lock);
2110 spin_lock_init(&gsm->tx_lock);
2112 if (gsm->encoding == 0)
2113 gsm->receive = gsm0_receive;
2115 gsm->receive = gsm1_receive;
2116 gsm->error = gsm_error;
2118 spin_lock(&gsm_mux_lock);
2119 for (i = 0; i < MAX_MUX; i++) {
2120 if (gsm_mux[i] == NULL) {
2126 spin_unlock(&gsm_mux_lock);
2130 dlci = gsm_dlci_alloc(gsm, 0);
2133 gsm->dead = 0; /* Tty opens are now permissible */
2136 EXPORT_SYMBOL_GPL(gsm_activate_mux);
2139 * gsm_free_mux - free up a mux
2142 * Dispose of allocated resources for a dead mux
2144 void gsm_free_mux(struct gsm_mux *gsm)
2146 kfree(gsm->txframe);
2150 EXPORT_SYMBOL_GPL(gsm_free_mux);
2153 * gsm_free_muxr - free up a mux
2156 * Dispose of allocated resources for a dead mux
2158 static void gsm_free_muxr(struct kref *ref)
2160 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref);
2164 static inline void mux_get(struct gsm_mux *gsm)
2166 kref_get(&gsm->ref);
2169 static inline void mux_put(struct gsm_mux *gsm)
2171 kref_put(&gsm->ref, gsm_free_muxr);
2175 * gsm_alloc_mux - allocate a mux
2177 * Creates a new mux ready for activation.
2180 struct gsm_mux *gsm_alloc_mux(void)
2182 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
2185 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL);
2186 if (gsm->buf == NULL) {
2190 gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL);
2191 if (gsm->txframe == NULL) {
2196 spin_lock_init(&gsm->lock);
2197 kref_init(&gsm->ref);
2205 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
2207 gsm->dead = 1; /* Avoid early tty opens */
2211 EXPORT_SYMBOL_GPL(gsm_alloc_mux);
2214 * gsmld_output - write to link
2216 * @data: bytes to output
2219 * Write a block of data from the GSM mux to the data channel. This
2220 * will eventually be serialized from above but at the moment isn't.
2223 static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
2225 if (tty_write_room(gsm->tty) < len) {
2226 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
2230 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET,
2232 gsm->tty->ops->write(gsm->tty, data, len);
2237 * gsmld_attach_gsm - mode set up
2238 * @tty: our tty structure
2241 * Set up the MUX for basic mode and commence connecting to the
2242 * modem. Currently called from the line discipline set up but
2243 * will need moving to an ioctl path.
2246 static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2249 int base = gsm->num << 6; /* Base for this MUX */
2251 gsm->tty = tty_kref_get(tty);
2252 gsm->output = gsmld_output;
2253 ret = gsm_activate_mux(gsm);
2255 tty_kref_put(gsm->tty);
2257 /* Don't register device 0 - this is the control channel and not
2258 a usable tty interface */
2259 for (i = 1; i < NUM_DLCI; i++)
2260 tty_register_device(gsm_tty_driver, base + i, NULL);
2267 * gsmld_detach_gsm - stop doing 0710 mux
2268 * @tty: tty attached to the mux
2271 * Shutdown and then clean up the resources used by the line discipline
2274 static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2277 int base = gsm->num << 6; /* Base for this MUX */
2279 WARN_ON(tty != gsm->tty);
2280 for (i = 1; i < NUM_DLCI; i++)
2281 tty_unregister_device(gsm_tty_driver, base + i);
2282 gsm_cleanup_mux(gsm);
2283 tty_kref_put(gsm->tty);
2287 static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
2288 char *fp, int count)
2290 struct gsm_mux *gsm = tty->disc_data;
2291 const unsigned char *dp;
2298 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET,
2301 for (i = count, dp = cp, f = fp; i; i--, dp++) {
2305 gsm->receive(gsm, *dp);
2311 gsm->error(gsm, *dp, flags);
2314 WARN_ONCE(1, "%s: unknown flag %d\n",
2315 tty_name(tty, buf), flags);
2319 /* FASYNC if needed ? */
2320 /* If clogged call tty_throttle(tty); */
2324 * gsmld_chars_in_buffer - report available bytes
2327 * Report the number of characters buffered to be delivered to user
2328 * at this instant in time.
2333 static ssize_t gsmld_chars_in_buffer(struct tty_struct *tty)
2339 * gsmld_flush_buffer - clean input queue
2340 * @tty: terminal device
2342 * Flush the input buffer. Called when the line discipline is
2343 * being closed, when the tty layer wants the buffer flushed (eg
2347 static void gsmld_flush_buffer(struct tty_struct *tty)
2352 * gsmld_close - close the ldisc for this tty
2355 * Called from the terminal layer when this line discipline is
2356 * being shut down, either because of a close or becsuse of a
2357 * discipline change. The function will not be called while other
2358 * ldisc methods are in progress.
2361 static void gsmld_close(struct tty_struct *tty)
2363 struct gsm_mux *gsm = tty->disc_data;
2365 gsmld_detach_gsm(tty, gsm);
2367 gsmld_flush_buffer(tty);
2368 /* Do other clean up here */
2373 * gsmld_open - open an ldisc
2374 * @tty: terminal to open
2376 * Called when this line discipline is being attached to the
2377 * terminal device. Can sleep. Called serialized so that no
2378 * other events will occur in parallel. No further open will occur
2382 static int gsmld_open(struct tty_struct *tty)
2384 struct gsm_mux *gsm;
2386 if (tty->ops->write == NULL)
2389 /* Attach our ldisc data */
2390 gsm = gsm_alloc_mux();
2394 tty->disc_data = gsm;
2395 tty->receive_room = 65536;
2397 /* Attach the initial passive connection */
2399 return gsmld_attach_gsm(tty, gsm);
2403 * gsmld_write_wakeup - asynchronous I/O notifier
2406 * Required for the ptys, serial driver etc. since processes
2407 * that attach themselves to the master and rely on ASYNC
2408 * IO must be woken up
2411 static void gsmld_write_wakeup(struct tty_struct *tty)
2413 struct gsm_mux *gsm = tty->disc_data;
2414 unsigned long flags;
2417 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2419 if (gsm->tx_bytes < TX_THRESH_LO) {
2420 spin_lock_irqsave(&gsm->tx_lock, flags);
2421 gsm_dlci_data_sweep(gsm);
2422 spin_unlock_irqrestore(&gsm->tx_lock, flags);
2427 * gsmld_read - read function for tty
2429 * @file: file object
2430 * @buf: userspace buffer pointer
2433 * Perform reads for the line discipline. We are guaranteed that the
2434 * line discipline will not be closed under us but we may get multiple
2435 * parallel readers and must handle this ourselves. We may also get
2436 * a hangup. Always called in user context, may sleep.
2438 * This code must be sure never to sleep through a hangup.
2441 static ssize_t gsmld_read(struct tty_struct *tty, struct file *file,
2442 unsigned char __user *buf, size_t nr)
2448 * gsmld_write - write function for tty
2450 * @file: file object
2451 * @buf: userspace buffer pointer
2454 * Called when the owner of the device wants to send a frame
2455 * itself (or some other control data). The data is transferred
2456 * as-is and must be properly framed and checksummed as appropriate
2457 * by userspace. Frames are either sent whole or not at all as this
2458 * avoids pain user side.
2461 static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
2462 const unsigned char *buf, size_t nr)
2464 int space = tty_write_room(tty);
2466 return tty->ops->write(tty, buf, nr);
2467 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2472 * gsmld_poll - poll method for N_GSM0710
2473 * @tty: terminal device
2474 * @file: file accessing it
2477 * Called when the line discipline is asked to poll() for data or
2478 * for special events. This code is not serialized with respect to
2479 * other events save open/close.
2481 * This code must be sure never to sleep through a hangup.
2482 * Called without the kernel lock held - fine
2485 static unsigned int gsmld_poll(struct tty_struct *tty, struct file *file,
2488 unsigned int mask = 0;
2489 struct gsm_mux *gsm = tty->disc_data;
2491 poll_wait(file, &tty->read_wait, wait);
2492 poll_wait(file, &tty->write_wait, wait);
2493 if (tty_hung_up_p(file))
2495 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
2496 mask |= POLLOUT | POLLWRNORM;
2502 static int gsmld_config(struct tty_struct *tty, struct gsm_mux *gsm,
2503 struct gsm_config *c)
2506 int need_restart = 0;
2508 /* Stuff we don't support yet - UI or I frame transport, windowing */
2509 if ((c->adaption != 1 && c->adaption != 2) || c->k)
2511 /* Check the MRU/MTU range looks sane */
2512 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8)
2516 if (c->encapsulation > 1) /* Basic, advanced, no I */
2518 if (c->initiator > 1)
2520 if (c->i == 0 || c->i > 2) /* UIH and UI only */
2523 * See what is needed for reconfiguration
2527 if (c->t1 != 0 && c->t1 != gsm->t1)
2529 if (c->t2 != 0 && c->t2 != gsm->t2)
2531 if (c->encapsulation != gsm->encoding)
2533 if (c->adaption != gsm->adaption)
2536 if (c->initiator != gsm->initiator)
2538 if (c->mru != gsm->mru)
2540 if (c->mtu != gsm->mtu)
2544 * Close down what is needed, restart and initiate the new
2548 if (need_close || need_restart) {
2549 gsm_dlci_begin_close(gsm->dlci[0]);
2550 /* This will timeout if the link is down due to N2 expiring */
2551 wait_event_interruptible(gsm->event,
2552 gsm->dlci[0]->state == DLCI_CLOSED);
2553 if (signal_pending(current))
2557 gsm_cleanup_mux(gsm);
2559 gsm->initiator = c->initiator;
2562 gsm->encoding = c->encapsulation;
2563 gsm->adaption = c->adaption;
2576 /* FIXME: We need to separate activation/deactivation from adding
2577 and removing from the mux array */
2579 gsm_activate_mux(gsm);
2580 if (gsm->initiator && need_close)
2581 gsm_dlci_begin_open(gsm->dlci[0]);
2585 static int gsmld_ioctl(struct tty_struct *tty, struct file *file,
2586 unsigned int cmd, unsigned long arg)
2588 struct gsm_config c;
2589 struct gsm_mux *gsm = tty->disc_data;
2592 case GSMIOC_GETCONF:
2593 memset(&c, 0, sizeof(c));
2594 c.adaption = gsm->adaption;
2595 c.encapsulation = gsm->encoding;
2596 c.initiator = gsm->initiator;
2599 c.t3 = 0; /* Not supported */
2601 if (gsm->ftype == UIH)
2605 pr_debug("Ftype %d i %d\n", gsm->ftype, c.i);
2609 if (copy_to_user((void *)arg, &c, sizeof(c)))
2612 case GSMIOC_SETCONF:
2613 if (copy_from_user(&c, (void *)arg, sizeof(c)))
2615 return gsmld_config(tty, gsm, &c);
2617 return n_tty_ioctl_helper(tty, file, cmd, arg);
2626 static int gsm_mux_net_open(struct net_device *net)
2628 pr_debug("%s called\n", __func__);
2629 netif_start_queue(net);
2633 static int gsm_mux_net_close(struct net_device *net)
2635 netif_stop_queue(net);
2639 static struct net_device_stats *gsm_mux_net_get_stats(struct net_device *net)
2641 return &((struct gsm_mux_net *)netdev_priv(net))->stats;
2643 static void dlci_net_free(struct gsm_dlci *dlci)
2649 dlci->adaption = dlci->prev_adaption;
2650 dlci->data = dlci->prev_data;
2651 free_netdev(dlci->net);
2654 static void net_free(struct kref *ref)
2656 struct gsm_mux_net *mux_net;
2657 struct gsm_dlci *dlci;
2659 mux_net = container_of(ref, struct gsm_mux_net, ref);
2660 dlci = mux_net->dlci;
2663 unregister_netdev(dlci->net);
2664 dlci_net_free(dlci);
2668 static inline void muxnet_get(struct gsm_mux_net *mux_net)
2670 kref_get(&mux_net->ref);
2673 static inline void muxnet_put(struct gsm_mux_net *mux_net)
2675 kref_put(&mux_net->ref, net_free);
2678 static int gsm_mux_net_start_xmit(struct sk_buff *skb,
2679 struct net_device *net)
2681 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
2682 struct gsm_dlci *dlci = mux_net->dlci;
2683 muxnet_get(mux_net);
2685 skb_queue_head(&dlci->skb_list, skb);
2686 STATS(net).tx_packets++;
2687 STATS(net).tx_bytes += skb->len;
2688 gsm_dlci_data_kick(dlci);
2689 /* And tell the kernel when the last transmit started. */
2690 net->trans_start = jiffies;
2691 muxnet_put(mux_net);
2692 return NETDEV_TX_OK;
2695 /* called when a packet did not ack after watchdogtimeout */
2696 static void gsm_mux_net_tx_timeout(struct net_device *net)
2698 /* Tell syslog we are hosed. */
2699 dev_dbg(&net->dev, "Tx timed out.\n");
2701 /* Update statistics */
2702 STATS(net).tx_errors++;
2705 static void gsm_mux_rx_netchar(struct gsm_dlci *dlci,
2706 unsigned char *in_buf, int size)
2708 struct net_device *net = dlci->net;
2709 struct sk_buff *skb;
2710 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
2711 muxnet_get(mux_net);
2713 /* Allocate an sk_buff */
2714 skb = dev_alloc_skb(size + NET_IP_ALIGN);
2716 /* We got no receive buffer. */
2717 STATS(net).rx_dropped++;
2718 muxnet_put(mux_net);
2721 skb_reserve(skb, NET_IP_ALIGN);
2722 memcpy(skb_put(skb, size), in_buf, size);
2725 skb->protocol = __constant_htons(ETH_P_IP);
2727 /* Ship it off to the kernel */
2730 /* update out statistics */
2731 STATS(net).rx_packets++;
2732 STATS(net).rx_bytes += size;
2733 muxnet_put(mux_net);
2737 int gsm_change_mtu(struct net_device *net, int new_mtu)
2739 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
2740 if ((new_mtu < 8) || (new_mtu > mux_net->dlci->gsm->mtu))
2746 static void gsm_mux_net_init(struct net_device *net)
2748 static const struct net_device_ops gsm_netdev_ops = {
2749 .ndo_open = gsm_mux_net_open,
2750 .ndo_stop = gsm_mux_net_close,
2751 .ndo_start_xmit = gsm_mux_net_start_xmit,
2752 .ndo_tx_timeout = gsm_mux_net_tx_timeout,
2753 .ndo_get_stats = gsm_mux_net_get_stats,
2754 .ndo_change_mtu = gsm_change_mtu,
2757 net->netdev_ops = &gsm_netdev_ops;
2759 /* fill in the other fields */
2760 net->watchdog_timeo = GSM_NET_TX_TIMEOUT;
2761 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
2762 net->type = ARPHRD_NONE;
2763 net->tx_queue_len = 10;
2767 /* caller holds the dlci mutex */
2768 static void gsm_destroy_network(struct gsm_dlci *dlci)
2770 struct gsm_mux_net *mux_net;
2772 pr_debug("destroy network interface");
2775 mux_net = (struct gsm_mux_net *)netdev_priv(dlci->net);
2776 muxnet_put(mux_net);
2780 /* caller holds the dlci mutex */
2781 static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
2785 struct net_device *net;
2786 struct gsm_mux_net *mux_net;
2788 if (!capable(CAP_NET_ADMIN))
2791 /* Already in a non tty mode */
2792 if (dlci->adaption > 2)
2795 if (nc->protocol != htons(ETH_P_IP))
2796 return -EPROTONOSUPPORT;
2798 if (nc->adaption != 3 && nc->adaption != 4)
2799 return -EPROTONOSUPPORT;
2801 pr_debug("create network interface");
2804 if (nc->if_name[0] != '\0')
2805 netname = nc->if_name;
2806 net = alloc_netdev(sizeof(struct gsm_mux_net),
2810 pr_err("alloc_netdev failed");
2813 net->mtu = dlci->gsm->mtu;
2814 mux_net = (struct gsm_mux_net *)netdev_priv(net);
2815 mux_net->dlci = dlci;
2816 kref_init(&mux_net->ref);
2817 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */
2819 /* reconfigure dlci for network */
2820 dlci->prev_adaption = dlci->adaption;
2821 dlci->prev_data = dlci->data;
2822 dlci->adaption = nc->adaption;
2823 dlci->data = gsm_mux_rx_netchar;
2826 pr_debug("register netdev");
2827 retval = register_netdev(net);
2829 pr_err("network register fail %d\n", retval);
2830 dlci_net_free(dlci);
2833 return net->ifindex; /* return network index */
2836 /* Line discipline for real tty */
2837 struct tty_ldisc_ops tty_ldisc_packet = {
2838 .owner = THIS_MODULE,
2839 .magic = TTY_LDISC_MAGIC,
2842 .close = gsmld_close,
2843 .flush_buffer = gsmld_flush_buffer,
2844 .chars_in_buffer = gsmld_chars_in_buffer,
2846 .write = gsmld_write,
2847 .ioctl = gsmld_ioctl,
2849 .receive_buf = gsmld_receive_buf,
2850 .write_wakeup = gsmld_write_wakeup
2859 static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk)
2862 struct gsm_control *ctrl;
2868 modembits[0] = len << 1 | EA; /* Data bytes */
2869 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */
2870 modembits[2] = gsm_encode_modem(dlci) << 1 | EA;
2872 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */
2873 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1);
2876 return gsm_control_wait(dlci->gsm, ctrl);
2879 static int gsm_carrier_raised(struct tty_port *port)
2881 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2882 /* Not yet open so no carrier info */
2883 if (dlci->state != DLCI_OPEN)
2887 return dlci->modem_rx & TIOCM_CD;
2890 static void gsm_dtr_rts(struct tty_port *port, int onoff)
2892 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2893 unsigned int modem_tx = dlci->modem_tx;
2895 modem_tx |= TIOCM_DTR | TIOCM_RTS;
2897 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
2898 if (modem_tx != dlci->modem_tx) {
2899 dlci->modem_tx = modem_tx;
2900 gsmtty_modem_update(dlci, 0);
2904 static const struct tty_port_operations gsm_port_ops = {
2905 .carrier_raised = gsm_carrier_raised,
2906 .dtr_rts = gsm_dtr_rts,
2910 static int gsmtty_open(struct tty_struct *tty, struct file *filp)
2912 struct gsm_mux *gsm;
2913 struct gsm_dlci *dlci;
2914 struct tty_port *port;
2915 unsigned int line = tty->index;
2916 unsigned int mux = line >> 6;
2922 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
2923 if (gsm_mux[mux] == NULL)
2925 if (line == 0 || line > 61) /* 62/63 reserved */
2930 /* If DLCI 0 is not yet fully open return an error. This is ok from a locking
2931 perspective as we don't have to worry about this if DLCI0 is lost */
2932 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN)
2934 dlci = gsm->dlci[line];
2936 dlci = gsm_dlci_alloc(gsm, line);
2941 tty->driver_data = dlci;
2943 dlci_get(dlci->gsm->dlci[0]);
2945 tty_port_tty_set(port, tty);
2948 /* We could in theory open and close before we wait - eg if we get
2949 a DM straight back. This is ok as that will have caused a hangup */
2950 set_bit(ASYNCB_INITIALIZED, &port->flags);
2951 /* Start sending off SABM messages */
2952 gsm_dlci_begin_open(dlci);
2953 /* And wait for virtual carrier */
2954 return tty_port_block_til_ready(port, tty, filp);
2957 static void gsmtty_close(struct tty_struct *tty, struct file *filp)
2959 struct gsm_dlci *dlci = tty->driver_data;
2960 struct gsm_mux *gsm;
2964 mutex_lock(&dlci->mutex);
2965 gsm_destroy_network(dlci);
2966 mutex_unlock(&dlci->mutex);
2968 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
2970 gsm_dlci_begin_close(dlci);
2971 tty_port_close_end(&dlci->port, tty);
2972 tty_port_tty_set(&dlci->port, NULL);
2975 dlci_put(gsm->dlci[0]);
2979 static void gsmtty_hangup(struct tty_struct *tty)
2981 struct gsm_dlci *dlci = tty->driver_data;
2982 tty_port_hangup(&dlci->port);
2983 gsm_dlci_begin_close(dlci);
2986 static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf,
2989 struct gsm_dlci *dlci = tty->driver_data;
2990 /* Stuff the bytes into the fifo queue */
2991 int sent = kfifo_in_locked(dlci->fifo, buf, len, &dlci->lock);
2992 /* Need to kick the channel */
2993 gsm_dlci_data_kick(dlci);
2997 static int gsmtty_write_room(struct tty_struct *tty)
2999 struct gsm_dlci *dlci = tty->driver_data;
3000 return TX_SIZE - kfifo_len(dlci->fifo);
3003 static int gsmtty_chars_in_buffer(struct tty_struct *tty)
3005 struct gsm_dlci *dlci = tty->driver_data;
3006 return kfifo_len(dlci->fifo);
3009 static void gsmtty_flush_buffer(struct tty_struct *tty)
3011 struct gsm_dlci *dlci = tty->driver_data;
3012 /* Caution needed: If we implement reliable transport classes
3013 then the data being transmitted can't simply be junked once
3014 it has first hit the stack. Until then we can just blow it
3016 kfifo_reset(dlci->fifo);
3017 /* Need to unhook this DLCI from the transmit queue logic */
3020 static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
3022 /* The FIFO handles the queue so the kernel will do the right
3023 thing waiting on chars_in_buffer before calling us. No work
3027 static int gsmtty_tiocmget(struct tty_struct *tty)
3029 struct gsm_dlci *dlci = tty->driver_data;
3030 return dlci->modem_rx;
3033 static int gsmtty_tiocmset(struct tty_struct *tty,
3034 unsigned int set, unsigned int clear)
3036 struct gsm_dlci *dlci = tty->driver_data;
3037 unsigned int modem_tx = dlci->modem_tx;
3042 if (modem_tx != dlci->modem_tx) {
3043 dlci->modem_tx = modem_tx;
3044 return gsmtty_modem_update(dlci, 0);
3050 static int gsmtty_ioctl(struct tty_struct *tty,
3051 unsigned int cmd, unsigned long arg)
3053 struct gsm_dlci *dlci = tty->driver_data;
3054 struct gsm_netconfig nc;
3058 case GSMIOC_ENABLE_NET:
3059 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc)))
3061 nc.if_name[IFNAMSIZ-1] = '\0';
3062 /* return net interface index or error code */
3063 mutex_lock(&dlci->mutex);
3064 index = gsm_create_network(dlci, &nc);
3065 mutex_unlock(&dlci->mutex);
3066 if (copy_to_user((void __user *)arg, &nc, sizeof(nc)))
3069 case GSMIOC_DISABLE_NET:
3070 if (!capable(CAP_NET_ADMIN))
3072 mutex_lock(&dlci->mutex);
3073 gsm_destroy_network(dlci);
3074 mutex_unlock(&dlci->mutex);
3077 return -ENOIOCTLCMD;
3081 static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old)
3083 /* For the moment its fixed. In actual fact the speed information
3084 for the virtual channel can be propogated in both directions by
3085 the RPN control message. This however rapidly gets nasty as we
3086 then have to remap modem signals each way according to whether
3087 our virtual cable is null modem etc .. */
3088 tty_termios_copy_hw(tty->termios, old);
3091 static void gsmtty_throttle(struct tty_struct *tty)
3093 struct gsm_dlci *dlci = tty->driver_data;
3094 if (tty->termios->c_cflag & CRTSCTS)
3095 dlci->modem_tx &= ~TIOCM_DTR;
3096 dlci->throttled = 1;
3097 /* Send an MSC with DTR cleared */
3098 gsmtty_modem_update(dlci, 0);
3101 static void gsmtty_unthrottle(struct tty_struct *tty)
3103 struct gsm_dlci *dlci = tty->driver_data;
3104 if (tty->termios->c_cflag & CRTSCTS)
3105 dlci->modem_tx |= TIOCM_DTR;
3106 dlci->throttled = 0;
3107 /* Send an MSC with DTR set */
3108 gsmtty_modem_update(dlci, 0);
3111 static int gsmtty_break_ctl(struct tty_struct *tty, int state)
3113 struct gsm_dlci *dlci = tty->driver_data;
3114 int encode = 0; /* Off */
3116 if (state == -1) /* "On indefinitely" - we can't encode this
3119 else if (state > 0) {
3120 encode = state / 200; /* mS to encoding */
3122 encode = 0x0F; /* Best effort */
3124 return gsmtty_modem_update(dlci, encode);
3128 /* Virtual ttys for the demux */
3129 static const struct tty_operations gsmtty_ops = {
3130 .open = gsmtty_open,
3131 .close = gsmtty_close,
3132 .write = gsmtty_write,
3133 .write_room = gsmtty_write_room,
3134 .chars_in_buffer = gsmtty_chars_in_buffer,
3135 .flush_buffer = gsmtty_flush_buffer,
3136 .ioctl = gsmtty_ioctl,
3137 .throttle = gsmtty_throttle,
3138 .unthrottle = gsmtty_unthrottle,
3139 .set_termios = gsmtty_set_termios,
3140 .hangup = gsmtty_hangup,
3141 .wait_until_sent = gsmtty_wait_until_sent,
3142 .tiocmget = gsmtty_tiocmget,
3143 .tiocmset = gsmtty_tiocmset,
3144 .break_ctl = gsmtty_break_ctl,
3149 static int __init gsm_init(void)
3151 /* Fill in our line protocol discipline, and register it */
3152 int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet);
3154 pr_err("n_gsm: can't register line discipline (err = %d)\n",
3159 gsm_tty_driver = alloc_tty_driver(256);
3160 if (!gsm_tty_driver) {
3161 tty_unregister_ldisc(N_GSM0710);
3162 pr_err("gsm_init: tty allocation failed.\n");
3165 gsm_tty_driver->owner = THIS_MODULE;
3166 gsm_tty_driver->driver_name = "gsmtty";
3167 gsm_tty_driver->name = "gsmtty";
3168 gsm_tty_driver->major = 0; /* Dynamic */
3169 gsm_tty_driver->minor_start = 0;
3170 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
3171 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
3172 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV
3173 | TTY_DRIVER_HARDWARE_BREAK;
3174 gsm_tty_driver->init_termios = tty_std_termios;
3176 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
3177 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
3179 spin_lock_init(&gsm_mux_lock);
3181 if (tty_register_driver(gsm_tty_driver)) {
3182 put_tty_driver(gsm_tty_driver);
3183 tty_unregister_ldisc(N_GSM0710);
3184 pr_err("gsm_init: tty registration failed.\n");
3187 pr_debug("gsm_init: loaded as %d,%d.\n",
3188 gsm_tty_driver->major, gsm_tty_driver->minor_start);
3192 static void __exit gsm_exit(void)
3194 int status = tty_unregister_ldisc(N_GSM0710);
3196 pr_err("n_gsm: can't unregister line discipline (err = %d)\n",
3198 tty_unregister_driver(gsm_tty_driver);
3199 put_tty_driver(gsm_tty_driver);
3202 module_init(gsm_init);
3203 module_exit(gsm_exit);
3206 MODULE_LICENSE("GPL");
3207 MODULE_ALIAS_LDISC(N_GSM0710);