1 // SPDX-License-Identifier: GPL-2.0
3 * n_gsm.c GSM 0710 tty multiplexor
4 * Copyright (c) 2009/10 Intel Corporation
6 * * THIS IS A DEVELOPMENT SNAPSHOT IT IS NOT A FINAL RELEASE *
9 * Mostly done: ioctls for setting modes/timing
10 * Partly done: hooks so you can pull off frames to non tty devs
11 * Restart DLCI 0 when it closes ?
12 * Improve the tx engine
13 * Resolve tx side locking by adding a queue_head and routing
14 * all control traffic via it
15 * General tidy/document
16 * Review the locking/move to refcounts more (mux now moved to an
17 * alloc/free model ready)
18 * Use newest tty open/close port helpers and install hooks
19 * What to do about power functions ?
20 * Termios setting and negotiation
21 * Do we need a 'which mux are you' ioctl to correlate mux and tty sets
25 #include <linux/types.h>
26 #include <linux/major.h>
27 #include <linux/errno.h>
28 #include <linux/signal.h>
29 #include <linux/fcntl.h>
30 #include <linux/sched/signal.h>
31 #include <linux/interrupt.h>
32 #include <linux/tty.h>
33 #include <linux/ctype.h>
35 #include <linux/string.h>
36 #include <linux/slab.h>
37 #include <linux/poll.h>
38 #include <linux/bitops.h>
39 #include <linux/file.h>
40 #include <linux/uaccess.h>
41 #include <linux/module.h>
42 #include <linux/timer.h>
43 #include <linux/tty_flip.h>
44 #include <linux/tty_driver.h>
45 #include <linux/serial.h>
46 #include <linux/kfifo.h>
47 #include <linux/skbuff.h>
50 #include <linux/netdevice.h>
51 #include <linux/etherdevice.h>
52 #include <linux/gsmmux.h>
56 module_param(debug, int, 0600);
58 /* Defaults: these are from the specification */
60 #define T1 10 /* 100mS */
61 #define T2 34 /* 333mS */
62 #define N2 3 /* Retry 3 times */
64 /* Use long timers for testing at low speed with debug on */
71 * Semi-arbitrary buffer size limits. 0710 is normally run with 32-64 byte
72 * limits so this is plenty
76 #define GSM_NET_TX_TIMEOUT (HZ*10)
79 * struct gsm_mux_net - network interface
81 * Created when net interface is initialized.
85 struct gsm_dlci *dlci;
89 * Each block of data we have queued to go out is in the form of
90 * a gsm_msg which holds everything we need in a link layer independent
95 struct list_head list;
96 u8 addr; /* DLCI address + flags */
97 u8 ctrl; /* Control byte + flags */
98 unsigned int len; /* Length of data block (can be zero) */
99 unsigned char *data; /* Points into buffer but not at the start */
100 unsigned char buffer[];
103 enum gsm_dlci_state {
105 DLCI_OPENING, /* Sending SABM not seen UA */
106 DLCI_OPEN, /* SABM/UA complete */
107 DLCI_CLOSING, /* Sending DISC not seen UA/DM */
111 DLCI_MODE_ABM, /* Normal Asynchronous Balanced Mode */
112 DLCI_MODE_ADM, /* Asynchronous Disconnected Mode */
116 * Each active data link has a gsm_dlci structure associated which ties
117 * the link layer to an optional tty (if the tty side is open). To avoid
118 * complexity right now these are only ever freed up when the mux is
121 * At the moment we don't free DLCI objects until the mux is torn down
122 * this avoid object life time issues but might be worth review later.
128 enum gsm_dlci_state state;
132 enum gsm_dlci_mode mode;
133 spinlock_t lock; /* Protects the internal state */
134 struct timer_list t1; /* Retransmit timer for SABM and UA */
136 /* Uplink tty if active */
137 struct tty_port port; /* The tty bound to this DLCI if there is one */
138 struct kfifo fifo; /* Queue fifo for the DLCI */
139 int adaption; /* Adaption layer in use */
141 u32 modem_rx; /* Our incoming virtual modem lines */
142 u32 modem_tx; /* Our outgoing modem lines */
143 bool dead; /* Refuse re-open */
145 bool throttled; /* Private copy of throttle state */
146 bool constipated; /* Throttle status for outgoing */
148 struct sk_buff *skb; /* Frame being sent */
149 struct sk_buff_head skb_list; /* Queued frames */
150 /* Data handling callback */
151 void (*data)(struct gsm_dlci *dlci, const u8 *data, int len);
152 void (*prev_data)(struct gsm_dlci *dlci, const u8 *data, int len);
153 struct net_device *net; /* network interface, if created */
156 /* DLCI 0, 62/63 are special or reserved see gsmtty_open */
161 * DLCI 0 is used to pass control blocks out of band of the data
162 * flow (and with a higher link priority). One command can be outstanding
163 * at a time and we use this structure to manage them. They are created
164 * and destroyed by the user context, and updated by the receive paths
169 u8 cmd; /* Command we are issuing */
170 u8 *data; /* Data for the command in case we retransmit */
171 int len; /* Length of block for retransmission */
172 int done; /* Done flag */
173 int error; /* Error if any */
191 * Each GSM mux we have is represented by this structure. If we are
192 * operating as an ldisc then we use this structure as our ldisc
193 * state. We need to sort out lifetimes and locking with respect
194 * to the gsm mux array. For now we don't free DLCI objects that
195 * have been instantiated until the mux itself is terminated.
197 * To consider further: tty open versus mux shutdown.
201 struct tty_struct *tty; /* The tty our ldisc is bound to */
207 /* Events on the GSM channel */
208 wait_queue_head_t event;
210 /* Bits for GSM mode decoding */
214 enum gsm_mux_state state;
216 unsigned int address;
223 u8 *txframe; /* TX framing buffer */
225 /* Method for the receiver side */
226 void (*receive)(struct gsm_mux *gsm, u8 ch);
231 int initiator; /* Did we initiate connection */
232 bool dead; /* Has the mux been shut down */
233 struct gsm_dlci *dlci[NUM_DLCI];
234 bool constipated; /* Asked by remote to shut up */
237 unsigned int tx_bytes; /* TX data outstanding */
238 #define TX_THRESH_HI 8192
239 #define TX_THRESH_LO 2048
240 struct list_head tx_list; /* Pending data packets */
242 /* Control messages */
243 struct timer_list t2_timer; /* Retransmit timer for commands */
244 int cretries; /* Command retry counter */
245 struct gsm_control *pending_cmd;/* Our current pending command */
246 spinlock_t control_lock; /* Protects the pending command */
249 int adaption; /* 1 or 2 supported */
250 u8 ftype; /* UI or UIH */
251 int t1, t2; /* Timers in 1/100th of a sec */
252 int n2; /* Retry count */
254 /* Statistics (not currently exposed) */
255 unsigned long bad_fcs;
256 unsigned long malformed;
257 unsigned long io_error;
258 unsigned long bad_size;
259 unsigned long unsupported;
264 * Mux objects - needed so that we can translate a tty index into the
265 * relevant mux and DLCI.
268 #define MAX_MUX 4 /* 256 minors */
269 static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */
270 static DEFINE_SPINLOCK(gsm_mux_lock);
272 static struct tty_driver *gsm_tty_driver;
274 /* Save dlci open address */
275 static int addr_open[256] = { 0 };
276 /* Save dlci open count */
279 * This section of the driver logic implements the GSM encodings
280 * both the basic and the 'advanced'. Reliable transport is not
288 /* I is special: the rest are ..*/
299 /* Channel commands */
301 #define CMD_TEST 0x11
304 #define CMD_FCOFF 0x31
307 #define CMD_FCON 0x51
312 /* Virtual modem bits */
319 #define GSM0_SOF 0xF9
320 #define GSM1_SOF 0x7E
321 #define GSM1_ESCAPE 0x7D
322 #define GSM1_ESCAPE_BITS 0x20
326 static const struct tty_port_operations gsm_port_ops;
329 * CRC table for GSM 0710
332 static const u8 gsm_fcs8[256] = {
333 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75,
334 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B,
335 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69,
336 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67,
337 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D,
338 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43,
339 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51,
340 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F,
341 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05,
342 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B,
343 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19,
344 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17,
345 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D,
346 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33,
347 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21,
348 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F,
349 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95,
350 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B,
351 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89,
352 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87,
353 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD,
354 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3,
355 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1,
356 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF,
357 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5,
358 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB,
359 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9,
360 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7,
361 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD,
362 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3,
363 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1,
364 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF
367 #define INIT_FCS 0xFF
368 #define GOOD_FCS 0xCF
370 static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len);
373 * gsm_fcs_add - update FCS
377 * Update the FCS to include c. Uses the algorithm in the specification
381 static inline u8 gsm_fcs_add(u8 fcs, u8 c)
383 return gsm_fcs8[fcs ^ c];
387 * gsm_fcs_add_block - update FCS for a block
390 * @len: length of buffer
392 * Update the FCS to include c. Uses the algorithm in the specification
396 static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len)
399 fcs = gsm_fcs8[fcs ^ *c++];
404 * gsm_read_ea - read a byte into an EA
405 * @val: variable holding value
406 * @c: byte going into the EA
408 * Processes one byte of an EA. Updates the passed variable
409 * and returns 1 if the EA is now completely read
412 static int gsm_read_ea(unsigned int *val, u8 c)
414 /* Add the next 7 bits into the value */
417 /* Was this the last byte of the EA 1 = yes*/
422 * gsm_encode_modem - encode modem data bits
423 * @dlci: DLCI to encode from
425 * Returns the correct GSM encoded modem status bits (6 bit field) for
426 * the current status of the DLCI and attached tty object
429 static u8 gsm_encode_modem(const struct gsm_dlci *dlci)
432 /* FC is true flow control not modem bits */
435 if (dlci->modem_tx & TIOCM_DTR)
436 modembits |= MDM_RTC;
437 if (dlci->modem_tx & TIOCM_RTS)
438 modembits |= MDM_RTR;
439 if (dlci->modem_tx & TIOCM_RI)
441 if (dlci->modem_tx & TIOCM_CD)
447 * gsm_print_packet - display a frame for debug
448 * @hdr: header to print before decode
449 * @addr: address EA from the frame
450 * @cr: C/R bit from the frame
451 * @control: control including PF bit
452 * @data: following data bytes
453 * @dlen: length of data
455 * Displays a packet in human readable format for debugging purposes. The
456 * style is based on amateur radio LAP-B dump display.
459 static void gsm_print_packet(const char *hdr, int addr, int cr,
460 u8 control, const u8 *data, int dlen)
465 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]);
467 switch (control & ~PF) {
487 if (!(control & 0x01)) {
488 pr_cont("I N(S)%d N(R)%d",
489 (control & 0x0E) >> 1, (control & 0xE0) >> 5);
490 } else switch (control & 0x0F) {
492 pr_cont("RR(%d)", (control & 0xE0) >> 5);
495 pr_cont("RNR(%d)", (control & 0xE0) >> 5);
498 pr_cont("REJ(%d)", (control & 0xE0) >> 5);
501 pr_cont("[%02X]", control);
510 print_hex_dump_bytes("", DUMP_PREFIX_NONE, data, dlen);
515 * Link level transmission side
519 * gsm_stuff_frame - bytestuff a packet
520 * @input: input buffer
521 * @output: output buffer
522 * @len: length of input
524 * Expand a buffer by bytestuffing it. The worst case size change
525 * is doubling and the caller is responsible for handing out
526 * suitable sized buffers.
529 static int gsm_stuff_frame(const u8 *input, u8 *output, int len)
533 if (*input == GSM1_SOF || *input == GSM1_ESCAPE
534 || *input == XON || *input == XOFF) {
535 *output++ = GSM1_ESCAPE;
536 *output++ = *input++ ^ GSM1_ESCAPE_BITS;
539 *output++ = *input++;
546 * gsm_send - send a control frame
548 * @addr: address for control frame
549 * @cr: command/response bit
550 * @control: control byte including PF bit
552 * Format up and transmit a control frame. These do not go via the
553 * queueing logic as they should be transmitted ahead of data when
556 * FIXME: Lock versus data TX path
559 static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control)
565 switch (gsm->encoding) {
568 cbuf[1] = (addr << 2) | (cr << 1) | EA;
570 cbuf[3] = EA; /* Length of data = 0 */
571 cbuf[4] = 0xFF - gsm_fcs_add_block(INIT_FCS, cbuf + 1, 3);
577 /* Control frame + packing (but not frame stuffing) in mode 1 */
578 ibuf[0] = (addr << 2) | (cr << 1) | EA;
580 ibuf[2] = 0xFF - gsm_fcs_add_block(INIT_FCS, ibuf, 2);
581 /* Stuffing may double the size worst case */
582 len = gsm_stuff_frame(ibuf, cbuf + 1, 3);
583 /* Now add the SOF markers */
585 cbuf[len + 1] = GSM1_SOF;
586 /* FIXME: we can omit the lead one in many cases */
593 gsmld_output(gsm, cbuf, len);
594 if (!gsm->initiator) {
595 cr = cr & gsm->initiator;
596 control = control & ~PF;
598 gsm_print_packet("-->", addr, cr, control, NULL, 0);
602 * gsm_response - send a control response
604 * @addr: address for control frame
605 * @control: control byte including PF bit
607 * Format up and transmit a link level response frame.
610 static inline void gsm_response(struct gsm_mux *gsm, int addr, int control)
612 gsm_send(gsm, addr, 1, control);
616 * gsm_command - send a control command
618 * @addr: address for control frame
619 * @control: control byte including PF bit
621 * Format up and transmit a link level command frame.
624 static inline void gsm_command(struct gsm_mux *gsm, int addr, int control)
626 gsm_send(gsm, addr, 1, control);
629 /* Data transmission */
631 #define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */
634 * gsm_data_alloc - allocate data frame
636 * @addr: DLCI address
637 * @len: length excluding header and FCS
638 * @ctrl: control byte
640 * Allocate a new data buffer for sending frames with data. Space is left
641 * at the front for header bytes but that is treated as an implementation
642 * detail and not for the high level code to use
645 static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
648 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN,
652 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */
656 INIT_LIST_HEAD(&m->list);
661 * gsm_data_kick - poke the queue
663 * @dlci: DLCI sending the data
665 * The tty device has called us to indicate that room has appeared in
666 * the transmit queue. Ram more data into the pipe if we have any
667 * If we have been flow-stopped by a CMD_FCOFF, then we can only
668 * send messages on DLCI0 until CMD_FCON
670 * FIXME: lock against link layer control transmissions
673 static void gsm_data_kick(struct gsm_mux *gsm, struct gsm_dlci *dlci)
675 struct gsm_msg *msg, *nmsg;
678 list_for_each_entry_safe(msg, nmsg, &gsm->tx_list, list) {
679 if (gsm->constipated && msg->addr)
681 if (gsm->encoding != 0) {
682 gsm->txframe[0] = GSM1_SOF;
683 len = gsm_stuff_frame(msg->data,
684 gsm->txframe + 1, msg->len);
685 gsm->txframe[len + 1] = GSM1_SOF;
688 gsm->txframe[0] = GSM0_SOF;
689 memcpy(gsm->txframe + 1 , msg->data, msg->len);
690 gsm->txframe[msg->len + 1] = GSM0_SOF;
695 print_hex_dump_bytes("gsm_data_kick: ",
698 if (gsmld_output(gsm, gsm->txframe, len) <= 0)
700 /* FIXME: Can eliminate one SOF in many more cases */
701 gsm->tx_bytes -= msg->len;
703 list_del(&msg->list);
707 tty_port_tty_wakeup(&dlci->port);
711 for (i = 0; i < NUM_DLCI; i++)
713 tty_port_tty_wakeup(&gsm->dlci[i]->port);
719 * __gsm_data_queue - queue a UI or UIH frame
720 * @dlci: DLCI sending the data
721 * @msg: message queued
723 * Add data to the transmit queue and try and get stuff moving
724 * out of the mux tty if not already doing so. The Caller must hold
728 static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
730 struct gsm_mux *gsm = dlci->gsm;
732 u8 *fcs = dp + msg->len;
734 /* Fill in the header */
735 if (gsm->encoding == 0) {
737 *--dp = (msg->len << 1) | EA;
739 *--dp = (msg->len >> 7); /* bits 7 - 15 */
740 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */
746 *--dp = (msg->addr << 2) | 2 | EA;
748 *--dp = (msg->addr << 2) | EA;
749 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp);
750 /* Ugly protocol layering violation */
751 if (msg->ctrl == UI || msg->ctrl == (UI|PF))
752 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len);
755 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl,
756 msg->data, msg->len);
758 /* Move the header back and adjust the length, also allow for the FCS
759 now tacked on the end */
760 msg->len += (msg->data - dp) + 1;
763 /* Add to the actual output queue */
764 list_add_tail(&msg->list, &gsm->tx_list);
765 gsm->tx_bytes += msg->len;
766 gsm_data_kick(gsm, dlci);
770 * gsm_data_queue - queue a UI or UIH frame
771 * @dlci: DLCI sending the data
772 * @msg: message queued
774 * Add data to the transmit queue and try and get stuff moving
775 * out of the mux tty if not already doing so. Take the
776 * the gsm tx lock and dlci lock.
779 static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
782 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
783 __gsm_data_queue(dlci, msg);
784 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
788 * gsm_dlci_data_output - try and push data out of a DLCI
790 * @dlci: the DLCI to pull data from
792 * Pull data from a DLCI and send it into the transmit queue if there
793 * is data. Keep to the MRU of the mux. This path handles the usual tty
794 * interface which is a byte stream with optional modem data.
796 * Caller must hold the tx_lock of the mux.
799 static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci)
803 int len, total_size, size;
804 int h = dlci->adaption - 1;
808 len = kfifo_len(&dlci->fifo);
812 /* MTU/MRU count only the data bits */
818 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
819 /* FIXME: need a timer or something to kick this so it can't
820 get stuck with no work outstanding and no buffer free */
824 switch (dlci->adaption) {
825 case 1: /* Unstructured */
827 case 2: /* Unstructed with modem bits.
828 Always one byte as we never send inline break data */
829 *dp++ = gsm_encode_modem(dlci);
832 WARN_ON(kfifo_out_locked(&dlci->fifo, dp , len, &dlci->lock) != len);
833 __gsm_data_queue(dlci, msg);
836 /* Bytes of data we used up */
841 * gsm_dlci_data_output_framed - try and push data out of a DLCI
843 * @dlci: the DLCI to pull data from
845 * Pull data from a DLCI and send it into the transmit queue if there
846 * is data. Keep to the MRU of the mux. This path handles framed data
847 * queued as skbuffs to the DLCI.
849 * Caller must hold the tx_lock of the mux.
852 static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
853 struct gsm_dlci *dlci)
858 int last = 0, first = 0;
861 /* One byte per frame is used for B/F flags */
862 if (dlci->adaption == 4)
865 /* dlci->skb is locked by tx_lock */
866 if (dlci->skb == NULL) {
867 dlci->skb = skb_dequeue_tail(&dlci->skb_list);
868 if (dlci->skb == NULL)
872 len = dlci->skb->len + overhead;
874 /* MTU/MRU count only the data bits */
875 if (len > gsm->mtu) {
876 if (dlci->adaption == 3) {
877 /* Over long frame, bin it */
878 dev_kfree_skb_any(dlci->skb);
886 size = len + overhead;
887 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
889 /* FIXME: need a timer or something to kick this so it can't
890 get stuck with no work outstanding and no buffer free */
892 skb_queue_tail(&dlci->skb_list, dlci->skb);
898 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */
899 /* Flag byte to carry the start/end info */
900 *dp++ = last << 7 | first << 6 | 1; /* EA */
903 memcpy(dp, dlci->skb->data, len);
904 skb_pull(dlci->skb, len);
905 __gsm_data_queue(dlci, msg);
907 dev_kfree_skb_any(dlci->skb);
914 * gsm_dlci_data_sweep - look for data to send
917 * Sweep the GSM mux channels in priority order looking for ones with
918 * data to send. We could do with optimising this scan a bit. We aim
919 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit
920 * TX_THRESH_LO we get called again
922 * FIXME: We should round robin between groups and in theory you can
923 * renegotiate DLCI priorities with optional stuff. Needs optimising.
926 static void gsm_dlci_data_sweep(struct gsm_mux *gsm)
929 /* Priority ordering: We should do priority with RR of the groups */
932 while (i < NUM_DLCI) {
933 struct gsm_dlci *dlci;
935 if (gsm->tx_bytes > TX_THRESH_HI)
938 if (dlci == NULL || dlci->constipated) {
942 if (dlci->adaption < 3 && !dlci->net)
943 len = gsm_dlci_data_output(gsm, dlci);
945 len = gsm_dlci_data_output_framed(gsm, dlci);
948 /* DLCI empty - try the next */
955 * gsm_dlci_data_kick - transmit if possible
956 * @dlci: DLCI to kick
958 * Transmit data from this DLCI if the queue is empty. We can't rely on
959 * a tty wakeup except when we filled the pipe so we need to fire off
960 * new data ourselves in other cases.
963 static void gsm_dlci_data_kick(struct gsm_dlci *dlci)
968 if (dlci->constipated)
971 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
972 /* If we have nothing running then we need to fire up */
973 sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO);
974 if (dlci->gsm->tx_bytes == 0) {
976 gsm_dlci_data_output_framed(dlci->gsm, dlci);
978 gsm_dlci_data_output(dlci->gsm, dlci);
981 gsm_dlci_data_sweep(dlci->gsm);
982 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
986 * Control message processing
991 * gsm_control_reply - send a response frame to a control
993 * @cmd: the command to use
994 * @data: data to follow encoded info
995 * @dlen: length of data
997 * Encode up and queue a UI/UIH frame containing our response.
1000 static void gsm_control_reply(struct gsm_mux *gsm, int cmd, const u8 *data,
1003 struct gsm_msg *msg;
1004 msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype);
1007 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */
1008 msg->data[1] = (dlen << 1) | EA;
1009 memcpy(msg->data + 2, data, dlen);
1010 gsm_data_queue(gsm->dlci[0], msg);
1014 * gsm_process_modem - process received modem status
1015 * @tty: virtual tty bound to the DLCI
1016 * @dlci: DLCI to affect
1017 * @modem: modem bits (full EA)
1018 * @clen: command length
1020 * Used when a modem control message or line state inline in adaption
1021 * layer 2 is processed. Sort out the local modem state and throttles
1024 static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
1025 u32 modem, int clen)
1031 /* The modem status command can either contain one octet (v.24 signals)
1032 or two octets (v.24 signals + break signals). The length field will
1033 either be 2 or 3 respectively. This is specified in section
1034 5.4.6.3.7 of the 27.010 mux spec. */
1037 modem = modem & 0x7f;
1040 modem = (modem >> 7) & 0x7f;
1043 /* Flow control/ready to communicate */
1044 fc = (modem & MDM_FC) || !(modem & MDM_RTR);
1045 if (fc && !dlci->constipated) {
1046 /* Need to throttle our output on this device */
1047 dlci->constipated = true;
1048 } else if (!fc && dlci->constipated) {
1049 dlci->constipated = false;
1050 gsm_dlci_data_kick(dlci);
1053 /* Map modem bits */
1054 if (modem & MDM_RTC)
1055 mlines |= TIOCM_DSR | TIOCM_DTR;
1056 if (modem & MDM_RTR)
1057 mlines |= TIOCM_RTS | TIOCM_CTS;
1063 /* Carrier drop -> hangup */
1065 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD))
1070 tty_insert_flip_char(&dlci->port, 0, TTY_BREAK);
1071 dlci->modem_rx = mlines;
1075 * gsm_control_modem - modem status received
1077 * @data: data following command
1078 * @clen: command length
1080 * We have received a modem status control message. This is used by
1081 * the GSM mux protocol to pass virtual modem line status and optionally
1082 * to indicate break signals. Unpack it, convert to Linux representation
1083 * and if need be stuff a break message down the tty.
1086 static void gsm_control_modem(struct gsm_mux *gsm, const u8 *data, int clen)
1088 unsigned int addr = 0;
1089 unsigned int modem = 0;
1090 unsigned int brk = 0;
1091 struct gsm_dlci *dlci;
1093 const u8 *dp = data;
1094 struct tty_struct *tty;
1096 while (gsm_read_ea(&addr, *dp++) == 0) {
1101 /* Must be at least one byte following the EA */
1107 /* Closed port, or invalid ? */
1108 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1110 dlci = gsm->dlci[addr];
1112 while (gsm_read_ea(&modem, *dp++) == 0) {
1119 while (gsm_read_ea(&brk, *dp++) == 0) {
1125 modem |= (brk & 0x7f);
1127 tty = tty_port_tty_get(&dlci->port);
1128 gsm_process_modem(tty, dlci, modem, clen);
1133 gsm_control_reply(gsm, CMD_MSC, data, clen);
1137 * gsm_control_rls - remote line status
1140 * @clen: data length
1142 * The modem sends us a two byte message on the control channel whenever
1143 * it wishes to send us an error state from the virtual link. Stuff
1144 * this into the uplink tty if present
1147 static void gsm_control_rls(struct gsm_mux *gsm, const u8 *data, int clen)
1149 struct tty_port *port;
1150 unsigned int addr = 0;
1153 const u8 *dp = data;
1155 while (gsm_read_ea(&addr, *dp++) == 0) {
1160 /* Must be at least one byte following ea */
1165 /* Closed port, or invalid ? */
1166 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1170 if ((bits & 1) == 0)
1173 port = &gsm->dlci[addr]->port;
1176 tty_insert_flip_char(port, 0, TTY_OVERRUN);
1178 tty_insert_flip_char(port, 0, TTY_PARITY);
1180 tty_insert_flip_char(port, 0, TTY_FRAME);
1182 tty_flip_buffer_push(port);
1184 gsm_control_reply(gsm, CMD_RLS, data, clen);
1187 static void gsm_dlci_begin_close(struct gsm_dlci *dlci);
1188 static void gsm_dlci_close(struct gsm_dlci *dlci);
1191 * gsm_control_message - DLCI 0 control processing
1193 * @command: the command EA
1194 * @data: data beyond the command/length EAs
1197 * Input processor for control messages from the other end of the link.
1198 * Processes the incoming request and queues a response frame or an
1199 * NSC response if not supported
1202 static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
1203 const u8 *data, int clen)
1206 unsigned long flags;
1207 struct gsm_dlci *dlci;
1214 for (i = 0; i < addr_cnt; i++) {
1215 address = addr_open[i];
1216 dlci = gsm->dlci[address];
1217 gsm_dlci_close(dlci);
1221 /* Modem wishes to close down */
1222 dlci = gsm->dlci[0];
1226 gsm_dlci_close(dlci);
1228 gsm_response(gsm, 0, UA|PF);
1233 /* Modem wishes to test, reply with the data */
1234 gsm_control_reply(gsm, CMD_TEST, data, clen);
1237 /* Modem can accept data again */
1238 gsm->constipated = false;
1239 gsm_control_reply(gsm, CMD_FCON, NULL, 0);
1240 /* Kick the link in case it is idling */
1241 spin_lock_irqsave(&gsm->tx_lock, flags);
1242 gsm_data_kick(gsm, NULL);
1243 spin_unlock_irqrestore(&gsm->tx_lock, flags);
1246 /* Modem wants us to STFU */
1247 gsm->constipated = true;
1248 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0);
1251 /* Out of band modem line change indicator for a DLCI */
1252 gsm_control_modem(gsm, data, clen);
1255 /* Out of band error reception for a DLCI */
1256 gsm_control_rls(gsm, data, clen);
1259 /* Modem wishes to enter power saving state */
1260 gsm_control_reply(gsm, CMD_PSC, NULL, 0);
1262 /* Optional unsupported commands */
1263 case CMD_PN: /* Parameter negotiation */
1264 case CMD_RPN: /* Remote port negotiation */
1265 case CMD_SNC: /* Service negotiation command */
1267 /* Reply to bad commands with an NSC */
1269 gsm_control_reply(gsm, CMD_NSC, buf, 1);
1275 * gsm_control_response - process a response to our control
1277 * @command: the command (response) EA
1278 * @data: data beyond the command/length EA
1281 * Process a response to an outstanding command. We only allow a single
1282 * control message in flight so this is fairly easy. All the clean up
1283 * is done by the caller, we just update the fields, flag it as done
1287 static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
1288 const u8 *data, int clen)
1290 struct gsm_control *ctrl;
1291 unsigned long flags;
1293 spin_lock_irqsave(&gsm->control_lock, flags);
1295 ctrl = gsm->pending_cmd;
1296 /* Does the reply match our command */
1298 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) {
1299 /* Our command was replied to, kill the retry timer */
1300 del_timer(&gsm->t2_timer);
1301 gsm->pending_cmd = NULL;
1302 /* Rejected by the other end */
1303 if (command == CMD_NSC)
1304 ctrl->error = -EOPNOTSUPP;
1306 wake_up(&gsm->event);
1308 spin_unlock_irqrestore(&gsm->control_lock, flags);
1312 * gsm_control_transmit - send control packet
1314 * @ctrl: frame to send
1316 * Send out a pending control command (called under control lock)
1319 static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl)
1321 struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, gsm->ftype);
1324 msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */
1325 memcpy(msg->data + 1, ctrl->data, ctrl->len);
1326 gsm_data_queue(gsm->dlci[0], msg);
1330 * gsm_control_retransmit - retransmit a control frame
1331 * @t: timer contained in our gsm object
1333 * Called off the T2 timer expiry in order to retransmit control frames
1334 * that have been lost in the system somewhere. The control_lock protects
1335 * us from colliding with another sender or a receive completion event.
1336 * In that situation the timer may still occur in a small window but
1337 * gsm->pending_cmd will be NULL and we just let the timer expire.
1340 static void gsm_control_retransmit(struct timer_list *t)
1342 struct gsm_mux *gsm = from_timer(gsm, t, t2_timer);
1343 struct gsm_control *ctrl;
1344 unsigned long flags;
1345 spin_lock_irqsave(&gsm->control_lock, flags);
1346 ctrl = gsm->pending_cmd;
1349 if (gsm->cretries == 0) {
1350 gsm->pending_cmd = NULL;
1351 ctrl->error = -ETIMEDOUT;
1353 spin_unlock_irqrestore(&gsm->control_lock, flags);
1354 wake_up(&gsm->event);
1357 gsm_control_transmit(gsm, ctrl);
1358 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1360 spin_unlock_irqrestore(&gsm->control_lock, flags);
1364 * gsm_control_send - send a control frame on DLCI 0
1365 * @gsm: the GSM channel
1366 * @command: command to send including CR bit
1367 * @data: bytes of data (must be kmalloced)
1368 * @clen: length of the block to send
1370 * Queue and dispatch a control command. Only one command can be
1371 * active at a time. In theory more can be outstanding but the matching
1372 * gets really complicated so for now stick to one outstanding.
1375 static struct gsm_control *gsm_control_send(struct gsm_mux *gsm,
1376 unsigned int command, u8 *data, int clen)
1378 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control),
1380 unsigned long flags;
1384 wait_event(gsm->event, gsm->pending_cmd == NULL);
1385 spin_lock_irqsave(&gsm->control_lock, flags);
1386 if (gsm->pending_cmd != NULL) {
1387 spin_unlock_irqrestore(&gsm->control_lock, flags);
1390 ctrl->cmd = command;
1393 gsm->pending_cmd = ctrl;
1395 /* If DLCI0 is in ADM mode skip retries, it won't respond */
1396 if (gsm->dlci[0]->mode == DLCI_MODE_ADM)
1399 gsm->cretries = gsm->n2;
1401 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1402 gsm_control_transmit(gsm, ctrl);
1403 spin_unlock_irqrestore(&gsm->control_lock, flags);
1408 * gsm_control_wait - wait for a control to finish
1410 * @control: control we are waiting on
1412 * Waits for the control to complete or time out. Frees any used
1413 * resources and returns 0 for success, or an error if the remote
1414 * rejected or ignored the request.
1417 static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
1420 wait_event(gsm->event, control->done == 1);
1421 err = control->error;
1428 * DLCI level handling: Needs krefs
1432 * State transitions and timers
1436 * gsm_dlci_close - a DLCI has closed
1437 * @dlci: DLCI that closed
1439 * Perform processing when moving a DLCI into closed state. If there
1440 * is an attached tty this is hung up
1443 static void gsm_dlci_close(struct gsm_dlci *dlci)
1445 del_timer(&dlci->t1);
1447 pr_debug("DLCI %d goes closed.\n", dlci->addr);
1448 dlci->state = DLCI_CLOSED;
1449 if (dlci->addr != 0) {
1450 tty_port_tty_hangup(&dlci->port, false);
1451 kfifo_reset(&dlci->fifo);
1453 dlci->gsm->dead = true;
1454 /* Unregister gsmtty driver,report gsmtty dev remove uevent for user */
1455 tty_unregister_device(gsm_tty_driver, dlci->addr);
1456 wake_up(&dlci->gsm->event);
1457 /* A DLCI 0 close is a MUX termination so we need to kick that
1458 back to userspace somehow */
1462 * gsm_dlci_open - a DLCI has opened
1463 * @dlci: DLCI that opened
1465 * Perform processing when moving a DLCI into open state.
1468 static void gsm_dlci_open(struct gsm_dlci *dlci)
1470 /* Note that SABM UA .. SABM UA first UA lost can mean that we go
1472 del_timer(&dlci->t1);
1473 /* This will let a tty open continue */
1474 dlci->state = DLCI_OPEN;
1476 pr_debug("DLCI %d goes open.\n", dlci->addr);
1477 /* Register gsmtty driver,report gsmtty dev add uevent for user */
1478 tty_register_device(gsm_tty_driver, dlci->addr, NULL);
1479 wake_up(&dlci->gsm->event);
1483 * gsm_dlci_t1 - T1 timer expiry
1484 * @t: timer contained in the DLCI that opened
1486 * The T1 timer handles retransmits of control frames (essentially of
1487 * SABM and DISC). We resend the command until the retry count runs out
1488 * in which case an opening port goes back to closed and a closing port
1489 * is simply put into closed state (any further frames from the other
1490 * end will get a DM response)
1492 * Some control dlci can stay in ADM mode with other dlci working just
1493 * fine. In that case we can just keep the control dlci open after the
1494 * DLCI_OPENING retries time out.
1497 static void gsm_dlci_t1(struct timer_list *t)
1499 struct gsm_dlci *dlci = from_timer(dlci, t, t1);
1500 struct gsm_mux *gsm = dlci->gsm;
1502 switch (dlci->state) {
1505 if (dlci->retries) {
1506 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1507 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1508 } else if (!dlci->addr && gsm->control == (DM | PF)) {
1510 pr_info("DLCI %d opening in ADM mode.\n",
1512 dlci->mode = DLCI_MODE_ADM;
1513 gsm_dlci_open(dlci);
1515 gsm_dlci_close(dlci);
1521 if (dlci->retries) {
1522 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1523 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1525 gsm_dlci_close(dlci);
1528 pr_debug("%s: unhandled state: %d\n", __func__, dlci->state);
1534 * gsm_dlci_begin_open - start channel open procedure
1535 * @dlci: DLCI to open
1537 * Commence opening a DLCI from the Linux side. We issue SABM messages
1538 * to the modem which should then reply with a UA or ADM, at which point
1539 * we will move into open state. Opening is done asynchronously with retry
1540 * running off timers and the responses.
1543 static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
1545 struct gsm_mux *gsm = dlci->gsm;
1546 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING)
1548 dlci->retries = gsm->n2;
1549 dlci->state = DLCI_OPENING;
1550 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1551 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1555 * gsm_dlci_begin_close - start channel open procedure
1556 * @dlci: DLCI to open
1558 * Commence closing a DLCI from the Linux side. We issue DISC messages
1559 * to the modem which should then reply with a UA, at which point we
1560 * will move into closed state. Closing is done asynchronously with retry
1561 * off timers. We may also receive a DM reply from the other end which
1562 * indicates the channel was already closed.
1565 static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
1567 struct gsm_mux *gsm = dlci->gsm;
1568 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
1570 dlci->retries = gsm->n2;
1571 dlci->state = DLCI_CLOSING;
1572 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1573 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1577 * gsm_dlci_data - data arrived
1579 * @data: block of bytes received
1580 * @clen: length of received block
1582 * A UI or UIH frame has arrived which contains data for a channel
1583 * other than the control channel. If the relevant virtual tty is
1584 * open we shovel the bits down it, if not we drop them.
1587 static void gsm_dlci_data(struct gsm_dlci *dlci, const u8 *data, int clen)
1590 struct tty_port *port = &dlci->port;
1591 struct tty_struct *tty;
1592 unsigned int modem = 0;
1596 pr_debug("%d bytes for tty\n", len);
1597 switch (dlci->adaption) {
1598 /* Unsupported types */
1599 case 4: /* Packetised interruptible data */
1601 case 3: /* Packetised uininterruptible voice/data */
1603 case 2: /* Asynchronous serial with line state in each frame */
1604 while (gsm_read_ea(&modem, *data++) == 0) {
1609 tty = tty_port_tty_get(port);
1611 gsm_process_modem(tty, dlci, modem, clen);
1615 case 1: /* Line state will go via DLCI 0 controls only */
1617 tty_insert_flip_string(port, data, len);
1618 tty_flip_buffer_push(port);
1623 * gsm_dlci_command - data arrived on control channel
1625 * @data: block of bytes received
1626 * @len: length of received block
1628 * A UI or UIH frame has arrived which contains data for DLCI 0 the
1629 * control channel. This should contain a command EA followed by
1630 * control data bytes. The command EA contains a command/response bit
1631 * and we divide up the work accordingly.
1634 static void gsm_dlci_command(struct gsm_dlci *dlci, const u8 *data, int len)
1636 /* See what command is involved */
1637 unsigned int command = 0;
1639 if (gsm_read_ea(&command, *data++) == 1) {
1642 /* FIXME: this is properly an EA */
1644 /* Malformed command ? */
1648 gsm_control_message(dlci->gsm, command,
1651 gsm_control_response(dlci->gsm, command,
1659 * Allocate/Free DLCI channels
1663 * gsm_dlci_alloc - allocate a DLCI
1665 * @addr: address of the DLCI
1667 * Allocate and install a new DLCI object into the GSM mux.
1669 * FIXME: review locking races
1672 static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
1674 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC);
1677 spin_lock_init(&dlci->lock);
1678 mutex_init(&dlci->mutex);
1679 if (kfifo_alloc(&dlci->fifo, 4096, GFP_KERNEL) < 0) {
1684 skb_queue_head_init(&dlci->skb_list);
1685 timer_setup(&dlci->t1, gsm_dlci_t1, 0);
1686 tty_port_init(&dlci->port);
1687 dlci->port.ops = &gsm_port_ops;
1690 dlci->adaption = gsm->adaption;
1691 dlci->state = DLCI_CLOSED;
1693 dlci->data = gsm_dlci_data;
1695 dlci->data = gsm_dlci_command;
1696 gsm->dlci[addr] = dlci;
1701 * gsm_dlci_free - free DLCI
1702 * @port: tty port for DLCI to free
1708 static void gsm_dlci_free(struct tty_port *port)
1710 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
1712 del_timer_sync(&dlci->t1);
1713 dlci->gsm->dlci[dlci->addr] = NULL;
1714 kfifo_free(&dlci->fifo);
1715 while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
1716 dev_kfree_skb(dlci->skb);
1720 static inline void dlci_get(struct gsm_dlci *dlci)
1722 tty_port_get(&dlci->port);
1725 static inline void dlci_put(struct gsm_dlci *dlci)
1727 tty_port_put(&dlci->port);
1730 static void gsm_destroy_network(struct gsm_dlci *dlci);
1733 * gsm_dlci_release - release DLCI
1734 * @dlci: DLCI to destroy
1736 * Release a DLCI. Actual free is deferred until either
1737 * mux is closed or tty is closed - whichever is last.
1741 static void gsm_dlci_release(struct gsm_dlci *dlci)
1743 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1745 mutex_lock(&dlci->mutex);
1746 gsm_destroy_network(dlci);
1747 mutex_unlock(&dlci->mutex);
1751 tty_port_tty_set(&dlci->port, NULL);
1754 dlci->state = DLCI_CLOSED;
1759 * LAPBish link layer logic
1763 * gsm_queue - a GSM frame is ready to process
1764 * @gsm: pointer to our gsm mux
1766 * At this point in time a frame has arrived and been demangled from
1767 * the line encoding. All the differences between the encodings have
1768 * been handled below us and the frame is unpacked into the structures.
1769 * The fcs holds the header FCS but any data FCS must be added here.
1772 static void gsm_queue(struct gsm_mux *gsm)
1774 struct gsm_dlci *dlci;
1777 int i, j, k, address_tmp;
1778 /* We have to sneak a look at the packet body to do the FCS.
1779 A somewhat layering violation in the spec */
1781 if ((gsm->control & ~PF) == UI)
1782 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len);
1783 if (gsm->encoding == 0) {
1784 /* WARNING: gsm->received_fcs is used for
1785 gsm->encoding = 0 only.
1786 In this case it contain the last piece of data
1787 required to generate final CRC */
1788 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs);
1790 if (gsm->fcs != GOOD_FCS) {
1793 pr_debug("BAD FCS %02x\n", gsm->fcs);
1796 address = gsm->address >> 1;
1797 if (address >= NUM_DLCI)
1800 cr = gsm->address & 1; /* C/R bit */
1802 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
1804 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */
1805 dlci = gsm->dlci[address];
1807 switch (gsm->control) {
1812 dlci = gsm_dlci_alloc(gsm, address);
1816 gsm_response(gsm, address, DM|PF);
1818 gsm_response(gsm, address, UA|PF);
1819 gsm_dlci_open(dlci);
1820 /* Save dlci open address */
1822 addr_open[addr_cnt] = address;
1830 if (dlci == NULL || dlci->state == DLCI_CLOSED) {
1831 gsm_response(gsm, address, DM|PF);
1834 /* Real close complete */
1837 for (i = 0; i < addr_cnt; i++) {
1838 address = addr_open[i];
1839 dlci = gsm->dlci[address];
1840 gsm_dlci_close(dlci);
1844 dlci = gsm->dlci[0];
1845 gsm_dlci_close(dlci);
1847 gsm_response(gsm, 0, UA|PF);
1849 gsm_response(gsm, address, UA|PF);
1850 gsm_dlci_close(dlci);
1851 /* clear dlci address */
1852 for (j = 0; j < addr_cnt; j++) {
1853 address_tmp = addr_open[j];
1854 if (address_tmp == address) {
1855 for (k = j; k < addr_cnt; k++)
1856 addr_open[k] = addr_open[k+1];
1865 if (cr == 0 || dlci == NULL)
1867 switch (dlci->state) {
1869 gsm_dlci_close(dlci);
1872 gsm_dlci_open(dlci);
1875 pr_debug("%s: unhandled state: %d\n", __func__,
1880 case DM: /* DM can be valid unsolicited */
1886 gsm_dlci_close(dlci);
1896 if (dlci == NULL || dlci->state != DLCI_OPEN) {
1897 gsm_command(gsm, address, DM|PF);
1900 dlci->data(dlci, gsm->buf, gsm->len);
1913 * gsm0_receive - perform processing for non-transparency
1914 * @gsm: gsm data for this ldisc instance
1917 * Receive bytes in gsm mode 0
1920 static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
1924 switch (gsm->state) {
1925 case GSM_SEARCH: /* SOF marker */
1926 if (c == GSM0_SOF) {
1927 gsm->state = GSM_ADDRESS;
1930 gsm->fcs = INIT_FCS;
1933 case GSM_ADDRESS: /* Address EA */
1934 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1935 if (gsm_read_ea(&gsm->address, c))
1936 gsm->state = GSM_CONTROL;
1938 case GSM_CONTROL: /* Control Byte */
1939 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1941 gsm->state = GSM_LEN0;
1943 case GSM_LEN0: /* Length EA */
1944 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1945 if (gsm_read_ea(&gsm->len, c)) {
1946 if (gsm->len > gsm->mru) {
1948 gsm->state = GSM_SEARCH;
1953 gsm->state = GSM_FCS;
1955 gsm->state = GSM_DATA;
1958 gsm->state = GSM_LEN1;
1961 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1963 gsm->len |= len << 7;
1964 if (gsm->len > gsm->mru) {
1966 gsm->state = GSM_SEARCH;
1971 gsm->state = GSM_FCS;
1973 gsm->state = GSM_DATA;
1975 case GSM_DATA: /* Data */
1976 gsm->buf[gsm->count++] = c;
1977 if (gsm->count == gsm->len)
1978 gsm->state = GSM_FCS;
1980 case GSM_FCS: /* FCS follows the packet */
1981 gsm->received_fcs = c;
1983 gsm->state = GSM_SSOF;
1986 if (c == GSM0_SOF) {
1987 gsm->state = GSM_SEARCH;
1992 pr_debug("%s: unhandled state: %d\n", __func__, gsm->state);
1998 * gsm1_receive - perform processing for non-transparency
1999 * @gsm: gsm data for this ldisc instance
2002 * Receive bytes in mode 1 (Advanced option)
2005 static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
2007 if (c == GSM1_SOF) {
2008 /* EOF is only valid in frame if we have got to the data state
2009 and received at least one byte (the FCS) */
2010 if (gsm->state == GSM_DATA && gsm->count) {
2011 /* Extract the FCS */
2013 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
2014 gsm->len = gsm->count;
2016 gsm->state = GSM_START;
2019 /* Any partial frame was a runt so go back to start */
2020 if (gsm->state != GSM_START) {
2022 gsm->state = GSM_START;
2024 /* A SOF in GSM_START means we are still reading idling or
2029 if (c == GSM1_ESCAPE) {
2034 /* Only an unescaped SOF gets us out of GSM search */
2035 if (gsm->state == GSM_SEARCH)
2039 c ^= GSM1_ESCAPE_BITS;
2040 gsm->escape = false;
2042 switch (gsm->state) {
2043 case GSM_START: /* First byte after SOF */
2045 gsm->state = GSM_ADDRESS;
2046 gsm->fcs = INIT_FCS;
2048 case GSM_ADDRESS: /* Address continuation */
2049 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2050 if (gsm_read_ea(&gsm->address, c))
2051 gsm->state = GSM_CONTROL;
2053 case GSM_CONTROL: /* Control Byte */
2054 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2057 gsm->state = GSM_DATA;
2059 case GSM_DATA: /* Data */
2060 if (gsm->count > gsm->mru) { /* Allow one for the FCS */
2061 gsm->state = GSM_OVERRUN;
2064 gsm->buf[gsm->count++] = c;
2066 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */
2069 pr_debug("%s: unhandled state: %d\n", __func__, gsm->state);
2075 * gsm_error - handle tty error
2078 * Handle an error in the receipt of data for a frame. Currently we just
2079 * go back to hunting for a SOF.
2081 * FIXME: better diagnostics ?
2084 static void gsm_error(struct gsm_mux *gsm)
2086 gsm->state = GSM_SEARCH;
2090 static int gsm_disconnect(struct gsm_mux *gsm)
2092 struct gsm_dlci *dlci = gsm->dlci[0];
2093 struct gsm_control *gc;
2098 /* In theory disconnecting DLCI 0 is sufficient but for some
2099 modems this is apparently not the case. */
2100 gc = gsm_control_send(gsm, CMD_CLD, NULL, 0);
2102 gsm_control_wait(gsm, gc);
2104 del_timer_sync(&gsm->t2_timer);
2105 /* Now we are sure T2 has stopped */
2107 gsm_dlci_begin_close(dlci);
2108 wait_event_interruptible(gsm->event,
2109 dlci->state == DLCI_CLOSED);
2111 if (signal_pending(current))
2118 * gsm_cleanup_mux - generic GSM protocol cleanup
2121 * Clean up the bits of the mux which are the same for all framing
2122 * protocols. Remove the mux from the mux table, stop all the timers
2123 * and then shut down each device hanging up the channels as we go.
2126 static void gsm_cleanup_mux(struct gsm_mux *gsm)
2129 struct gsm_dlci *dlci = gsm->dlci[0];
2130 struct gsm_msg *txq, *ntxq;
2134 spin_lock(&gsm_mux_lock);
2135 for (i = 0; i < MAX_MUX; i++) {
2136 if (gsm_mux[i] == gsm) {
2141 spin_unlock(&gsm_mux_lock);
2142 /* open failed before registering => nothing to do */
2146 del_timer_sync(&gsm->t2_timer);
2147 /* Now we are sure T2 has stopped */
2151 /* Free up any link layer users */
2152 mutex_lock(&gsm->mutex);
2153 for (i = 0; i < NUM_DLCI; i++)
2155 gsm_dlci_release(gsm->dlci[i]);
2156 mutex_unlock(&gsm->mutex);
2157 /* Now wipe the queues */
2158 list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list)
2160 INIT_LIST_HEAD(&gsm->tx_list);
2164 * gsm_activate_mux - generic GSM setup
2167 * Set up the bits of the mux which are the same for all framing
2168 * protocols. Add the mux to the mux table so it can be opened and
2169 * finally kick off connecting to DLCI 0 on the modem.
2172 static int gsm_activate_mux(struct gsm_mux *gsm)
2174 struct gsm_dlci *dlci;
2177 timer_setup(&gsm->t2_timer, gsm_control_retransmit, 0);
2178 init_waitqueue_head(&gsm->event);
2179 spin_lock_init(&gsm->control_lock);
2180 spin_lock_init(&gsm->tx_lock);
2182 if (gsm->encoding == 0)
2183 gsm->receive = gsm0_receive;
2185 gsm->receive = gsm1_receive;
2187 spin_lock(&gsm_mux_lock);
2188 for (i = 0; i < MAX_MUX; i++) {
2189 if (gsm_mux[i] == NULL) {
2195 spin_unlock(&gsm_mux_lock);
2199 dlci = gsm_dlci_alloc(gsm, 0);
2202 gsm->dead = false; /* Tty opens are now permissible */
2207 * gsm_free_mux - free up a mux
2210 * Dispose of allocated resources for a dead mux
2212 static void gsm_free_mux(struct gsm_mux *gsm)
2214 kfree(gsm->txframe);
2220 * gsm_free_muxr - free up a mux
2221 * @ref: kreference to the mux to free
2223 * Dispose of allocated resources for a dead mux
2225 static void gsm_free_muxr(struct kref *ref)
2227 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref);
2231 static inline void mux_get(struct gsm_mux *gsm)
2233 kref_get(&gsm->ref);
2236 static inline void mux_put(struct gsm_mux *gsm)
2238 kref_put(&gsm->ref, gsm_free_muxr);
2241 static inline unsigned int mux_num_to_base(struct gsm_mux *gsm)
2243 return gsm->num * NUM_DLCI;
2246 static inline unsigned int mux_line_to_num(unsigned int line)
2248 return line / NUM_DLCI;
2252 * gsm_alloc_mux - allocate a mux
2254 * Creates a new mux ready for activation.
2257 static struct gsm_mux *gsm_alloc_mux(void)
2259 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
2262 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL);
2263 if (gsm->buf == NULL) {
2267 gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL);
2268 if (gsm->txframe == NULL) {
2273 spin_lock_init(&gsm->lock);
2274 mutex_init(&gsm->mutex);
2275 kref_init(&gsm->ref);
2276 INIT_LIST_HEAD(&gsm->tx_list);
2284 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
2286 gsm->dead = true; /* Avoid early tty opens */
2291 static void gsm_copy_config_values(struct gsm_mux *gsm,
2292 struct gsm_config *c)
2294 memset(c, 0, sizeof(*c));
2295 c->adaption = gsm->adaption;
2296 c->encapsulation = gsm->encoding;
2297 c->initiator = gsm->initiator;
2300 c->t3 = 0; /* Not supported */
2302 if (gsm->ftype == UIH)
2306 pr_debug("Ftype %d i %d\n", gsm->ftype, c->i);
2312 static int gsm_config(struct gsm_mux *gsm, struct gsm_config *c)
2315 int need_restart = 0;
2317 /* Stuff we don't support yet - UI or I frame transport, windowing */
2318 if ((c->adaption != 1 && c->adaption != 2) || c->k)
2320 /* Check the MRU/MTU range looks sane */
2321 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8)
2325 if (c->encapsulation > 1) /* Basic, advanced, no I */
2327 if (c->initiator > 1)
2329 if (c->i == 0 || c->i > 2) /* UIH and UI only */
2332 * See what is needed for reconfiguration
2336 if (c->t1 != 0 && c->t1 != gsm->t1)
2338 if (c->t2 != 0 && c->t2 != gsm->t2)
2340 if (c->encapsulation != gsm->encoding)
2342 if (c->adaption != gsm->adaption)
2345 if (c->initiator != gsm->initiator)
2347 if (c->mru != gsm->mru)
2349 if (c->mtu != gsm->mtu)
2353 * Close down what is needed, restart and initiate the new
2357 if (gsm->initiator && (need_close || need_restart)) {
2360 ret = gsm_disconnect(gsm);
2366 gsm_cleanup_mux(gsm);
2368 gsm->initiator = c->initiator;
2371 gsm->encoding = c->encapsulation;
2372 gsm->adaption = c->adaption;
2386 * FIXME: We need to separate activation/deactivation from adding
2387 * and removing from the mux array
2390 gsm_activate_mux(gsm);
2391 if (gsm->initiator && need_close)
2392 gsm_dlci_begin_open(gsm->dlci[0]);
2397 * gsmld_output - write to link
2399 * @data: bytes to output
2402 * Write a block of data from the GSM mux to the data channel. This
2403 * will eventually be serialized from above but at the moment isn't.
2406 static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
2408 if (tty_write_room(gsm->tty) < len) {
2409 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
2413 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET,
2415 return gsm->tty->ops->write(gsm->tty, data, len);
2419 * gsmld_attach_gsm - mode set up
2420 * @tty: our tty structure
2423 * Set up the MUX for basic mode and commence connecting to the
2424 * modem. Currently called from the line discipline set up but
2425 * will need moving to an ioctl path.
2428 static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2433 gsm->tty = tty_kref_get(tty);
2434 ret = gsm_activate_mux(gsm);
2436 tty_kref_put(gsm->tty);
2438 /* Don't register device 0 - this is the control channel and not
2439 a usable tty interface */
2440 if (gsm->initiator) {
2441 base = mux_num_to_base(gsm); /* Base for this MUX */
2442 for (i = 1; i < NUM_DLCI; i++) {
2445 dev = tty_register_device(gsm_tty_driver,
2448 for (i--; i >= 1; i--)
2449 tty_unregister_device(gsm_tty_driver,
2451 return PTR_ERR(dev);
2461 * gsmld_detach_gsm - stop doing 0710 mux
2462 * @tty: tty attached to the mux
2465 * Shutdown and then clean up the resources used by the line discipline
2468 static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2470 unsigned int base = mux_num_to_base(gsm); /* Base for this MUX */
2473 WARN_ON(tty != gsm->tty);
2474 if (gsm->initiator) {
2475 for (i = 1; i < NUM_DLCI; i++)
2476 tty_unregister_device(gsm_tty_driver, base + i);
2478 gsm_cleanup_mux(gsm);
2479 tty_kref_put(gsm->tty);
2483 static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
2484 const char *fp, int count)
2486 struct gsm_mux *gsm = tty->disc_data;
2487 char flags = TTY_NORMAL;
2490 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET,
2493 for (; count; count--, cp++) {
2498 gsm->receive(gsm, *cp);
2507 WARN_ONCE(1, "%s: unknown flag %d\n",
2508 tty_name(tty), flags);
2512 /* FASYNC if needed ? */
2513 /* If clogged call tty_throttle(tty); */
2517 * gsmld_flush_buffer - clean input queue
2518 * @tty: terminal device
2520 * Flush the input buffer. Called when the line discipline is
2521 * being closed, when the tty layer wants the buffer flushed (eg
2525 static void gsmld_flush_buffer(struct tty_struct *tty)
2530 * gsmld_close - close the ldisc for this tty
2533 * Called from the terminal layer when this line discipline is
2534 * being shut down, either because of a close or becsuse of a
2535 * discipline change. The function will not be called while other
2536 * ldisc methods are in progress.
2539 static void gsmld_close(struct tty_struct *tty)
2541 struct gsm_mux *gsm = tty->disc_data;
2543 gsmld_detach_gsm(tty, gsm);
2545 gsmld_flush_buffer(tty);
2546 /* Do other clean up here */
2551 * gsmld_open - open an ldisc
2552 * @tty: terminal to open
2554 * Called when this line discipline is being attached to the
2555 * terminal device. Can sleep. Called serialized so that no
2556 * other events will occur in parallel. No further open will occur
2560 static int gsmld_open(struct tty_struct *tty)
2562 struct gsm_mux *gsm;
2565 if (tty->ops->write == NULL)
2568 /* Attach our ldisc data */
2569 gsm = gsm_alloc_mux();
2573 tty->disc_data = gsm;
2574 tty->receive_room = 65536;
2576 /* Attach the initial passive connection */
2579 ret = gsmld_attach_gsm(tty, gsm);
2581 gsm_cleanup_mux(gsm);
2588 * gsmld_write_wakeup - asynchronous I/O notifier
2591 * Required for the ptys, serial driver etc. since processes
2592 * that attach themselves to the master and rely on ASYNC
2593 * IO must be woken up
2596 static void gsmld_write_wakeup(struct tty_struct *tty)
2598 struct gsm_mux *gsm = tty->disc_data;
2599 unsigned long flags;
2602 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2603 spin_lock_irqsave(&gsm->tx_lock, flags);
2604 gsm_data_kick(gsm, NULL);
2605 if (gsm->tx_bytes < TX_THRESH_LO) {
2606 gsm_dlci_data_sweep(gsm);
2608 spin_unlock_irqrestore(&gsm->tx_lock, flags);
2612 * gsmld_read - read function for tty
2614 * @file: file object
2615 * @buf: userspace buffer pointer
2620 * Perform reads for the line discipline. We are guaranteed that the
2621 * line discipline will not be closed under us but we may get multiple
2622 * parallel readers and must handle this ourselves. We may also get
2623 * a hangup. Always called in user context, may sleep.
2625 * This code must be sure never to sleep through a hangup.
2628 static ssize_t gsmld_read(struct tty_struct *tty, struct file *file,
2629 unsigned char *buf, size_t nr,
2630 void **cookie, unsigned long offset)
2636 * gsmld_write - write function for tty
2638 * @file: file object
2639 * @buf: userspace buffer pointer
2642 * Called when the owner of the device wants to send a frame
2643 * itself (or some other control data). The data is transferred
2644 * as-is and must be properly framed and checksummed as appropriate
2645 * by userspace. Frames are either sent whole or not at all as this
2646 * avoids pain user side.
2649 static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
2650 const unsigned char *buf, size_t nr)
2652 int space = tty_write_room(tty);
2654 return tty->ops->write(tty, buf, nr);
2655 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2660 * gsmld_poll - poll method for N_GSM0710
2661 * @tty: terminal device
2662 * @file: file accessing it
2665 * Called when the line discipline is asked to poll() for data or
2666 * for special events. This code is not serialized with respect to
2667 * other events save open/close.
2669 * This code must be sure never to sleep through a hangup.
2670 * Called without the kernel lock held - fine
2673 static __poll_t gsmld_poll(struct tty_struct *tty, struct file *file,
2677 struct gsm_mux *gsm = tty->disc_data;
2679 poll_wait(file, &tty->read_wait, wait);
2680 poll_wait(file, &tty->write_wait, wait);
2681 if (tty_hung_up_p(file))
2683 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
2684 mask |= EPOLLOUT | EPOLLWRNORM;
2690 static int gsmld_ioctl(struct tty_struct *tty, unsigned int cmd,
2693 struct gsm_config c;
2694 struct gsm_mux *gsm = tty->disc_data;
2698 case GSMIOC_GETCONF:
2699 gsm_copy_config_values(gsm, &c);
2700 if (copy_to_user((void __user *)arg, &c, sizeof(c)))
2703 case GSMIOC_SETCONF:
2704 if (copy_from_user(&c, (void __user *)arg, sizeof(c)))
2706 return gsm_config(gsm, &c);
2707 case GSMIOC_GETFIRST:
2708 base = mux_num_to_base(gsm);
2709 return put_user(base + 1, (__u32 __user *)arg);
2711 return n_tty_ioctl_helper(tty, cmd, arg);
2720 static int gsm_mux_net_open(struct net_device *net)
2722 pr_debug("%s called\n", __func__);
2723 netif_start_queue(net);
2727 static int gsm_mux_net_close(struct net_device *net)
2729 netif_stop_queue(net);
2733 static void dlci_net_free(struct gsm_dlci *dlci)
2739 dlci->adaption = dlci->prev_adaption;
2740 dlci->data = dlci->prev_data;
2741 free_netdev(dlci->net);
2744 static void net_free(struct kref *ref)
2746 struct gsm_mux_net *mux_net;
2747 struct gsm_dlci *dlci;
2749 mux_net = container_of(ref, struct gsm_mux_net, ref);
2750 dlci = mux_net->dlci;
2753 unregister_netdev(dlci->net);
2754 dlci_net_free(dlci);
2758 static inline void muxnet_get(struct gsm_mux_net *mux_net)
2760 kref_get(&mux_net->ref);
2763 static inline void muxnet_put(struct gsm_mux_net *mux_net)
2765 kref_put(&mux_net->ref, net_free);
2768 static netdev_tx_t gsm_mux_net_start_xmit(struct sk_buff *skb,
2769 struct net_device *net)
2771 struct gsm_mux_net *mux_net = netdev_priv(net);
2772 struct gsm_dlci *dlci = mux_net->dlci;
2773 muxnet_get(mux_net);
2775 skb_queue_head(&dlci->skb_list, skb);
2776 net->stats.tx_packets++;
2777 net->stats.tx_bytes += skb->len;
2778 gsm_dlci_data_kick(dlci);
2779 /* And tell the kernel when the last transmit started. */
2780 netif_trans_update(net);
2781 muxnet_put(mux_net);
2782 return NETDEV_TX_OK;
2785 /* called when a packet did not ack after watchdogtimeout */
2786 static void gsm_mux_net_tx_timeout(struct net_device *net, unsigned int txqueue)
2788 /* Tell syslog we are hosed. */
2789 dev_dbg(&net->dev, "Tx timed out.\n");
2791 /* Update statistics */
2792 net->stats.tx_errors++;
2795 static void gsm_mux_rx_netchar(struct gsm_dlci *dlci,
2796 const unsigned char *in_buf, int size)
2798 struct net_device *net = dlci->net;
2799 struct sk_buff *skb;
2800 struct gsm_mux_net *mux_net = netdev_priv(net);
2801 muxnet_get(mux_net);
2803 /* Allocate an sk_buff */
2804 skb = dev_alloc_skb(size + NET_IP_ALIGN);
2806 /* We got no receive buffer. */
2807 net->stats.rx_dropped++;
2808 muxnet_put(mux_net);
2811 skb_reserve(skb, NET_IP_ALIGN);
2812 skb_put_data(skb, in_buf, size);
2815 skb->protocol = htons(ETH_P_IP);
2817 /* Ship it off to the kernel */
2820 /* update out statistics */
2821 net->stats.rx_packets++;
2822 net->stats.rx_bytes += size;
2823 muxnet_put(mux_net);
2827 static void gsm_mux_net_init(struct net_device *net)
2829 static const struct net_device_ops gsm_netdev_ops = {
2830 .ndo_open = gsm_mux_net_open,
2831 .ndo_stop = gsm_mux_net_close,
2832 .ndo_start_xmit = gsm_mux_net_start_xmit,
2833 .ndo_tx_timeout = gsm_mux_net_tx_timeout,
2836 net->netdev_ops = &gsm_netdev_ops;
2838 /* fill in the other fields */
2839 net->watchdog_timeo = GSM_NET_TX_TIMEOUT;
2840 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
2841 net->type = ARPHRD_NONE;
2842 net->tx_queue_len = 10;
2846 /* caller holds the dlci mutex */
2847 static void gsm_destroy_network(struct gsm_dlci *dlci)
2849 struct gsm_mux_net *mux_net;
2851 pr_debug("destroy network interface\n");
2854 mux_net = netdev_priv(dlci->net);
2855 muxnet_put(mux_net);
2859 /* caller holds the dlci mutex */
2860 static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
2864 struct net_device *net;
2865 struct gsm_mux_net *mux_net;
2867 if (!capable(CAP_NET_ADMIN))
2870 /* Already in a non tty mode */
2871 if (dlci->adaption > 2)
2874 if (nc->protocol != htons(ETH_P_IP))
2875 return -EPROTONOSUPPORT;
2877 if (nc->adaption != 3 && nc->adaption != 4)
2878 return -EPROTONOSUPPORT;
2880 pr_debug("create network interface\n");
2883 if (nc->if_name[0] != '\0')
2884 netname = nc->if_name;
2885 net = alloc_netdev(sizeof(struct gsm_mux_net), netname,
2886 NET_NAME_UNKNOWN, gsm_mux_net_init);
2888 pr_err("alloc_netdev failed\n");
2891 net->mtu = dlci->gsm->mtu;
2893 net->max_mtu = dlci->gsm->mtu;
2894 mux_net = netdev_priv(net);
2895 mux_net->dlci = dlci;
2896 kref_init(&mux_net->ref);
2897 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */
2899 /* reconfigure dlci for network */
2900 dlci->prev_adaption = dlci->adaption;
2901 dlci->prev_data = dlci->data;
2902 dlci->adaption = nc->adaption;
2903 dlci->data = gsm_mux_rx_netchar;
2906 pr_debug("register netdev\n");
2907 retval = register_netdev(net);
2909 pr_err("network register fail %d\n", retval);
2910 dlci_net_free(dlci);
2913 return net->ifindex; /* return network index */
2916 /* Line discipline for real tty */
2917 static struct tty_ldisc_ops tty_ldisc_packet = {
2918 .owner = THIS_MODULE,
2922 .close = gsmld_close,
2923 .flush_buffer = gsmld_flush_buffer,
2925 .write = gsmld_write,
2926 .ioctl = gsmld_ioctl,
2928 .receive_buf = gsmld_receive_buf,
2929 .write_wakeup = gsmld_write_wakeup
2938 static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk)
2941 struct gsm_control *ctrl;
2947 modembits[0] = len << 1 | EA; /* Data bytes */
2948 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */
2949 modembits[2] = gsm_encode_modem(dlci) << 1 | EA;
2951 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */
2952 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1);
2955 return gsm_control_wait(dlci->gsm, ctrl);
2958 static int gsm_carrier_raised(struct tty_port *port)
2960 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2961 struct gsm_mux *gsm = dlci->gsm;
2963 /* Not yet open so no carrier info */
2964 if (dlci->state != DLCI_OPEN)
2970 * Basic mode with control channel in ADM mode may not respond
2971 * to CMD_MSC at all and modem_rx is empty.
2973 if (gsm->encoding == 0 && gsm->dlci[0]->mode == DLCI_MODE_ADM &&
2977 return dlci->modem_rx & TIOCM_CD;
2980 static void gsm_dtr_rts(struct tty_port *port, int onoff)
2982 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2983 unsigned int modem_tx = dlci->modem_tx;
2985 modem_tx |= TIOCM_DTR | TIOCM_RTS;
2987 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
2988 if (modem_tx != dlci->modem_tx) {
2989 dlci->modem_tx = modem_tx;
2990 gsmtty_modem_update(dlci, 0);
2994 static const struct tty_port_operations gsm_port_ops = {
2995 .carrier_raised = gsm_carrier_raised,
2996 .dtr_rts = gsm_dtr_rts,
2997 .destruct = gsm_dlci_free,
3000 static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty)
3002 struct gsm_mux *gsm;
3003 struct gsm_dlci *dlci;
3004 unsigned int line = tty->index;
3005 unsigned int mux = mux_line_to_num(line);
3013 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
3014 if (gsm_mux[mux] == NULL)
3016 if (line == 0 || line > 61) /* 62/63 reserved */
3021 /* If DLCI 0 is not yet fully open return an error.
3022 This is ok from a locking
3023 perspective as we don't have to worry about this
3025 mutex_lock(&gsm->mutex);
3026 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN) {
3027 mutex_unlock(&gsm->mutex);
3030 dlci = gsm->dlci[line];
3033 dlci = gsm_dlci_alloc(gsm, line);
3036 mutex_unlock(&gsm->mutex);
3039 ret = tty_port_install(&dlci->port, driver, tty);
3043 mutex_unlock(&gsm->mutex);
3048 dlci_get(gsm->dlci[0]);
3050 tty->driver_data = dlci;
3051 mutex_unlock(&gsm->mutex);
3056 static int gsmtty_open(struct tty_struct *tty, struct file *filp)
3058 struct gsm_dlci *dlci = tty->driver_data;
3059 struct tty_port *port = &dlci->port;
3060 struct gsm_mux *gsm = dlci->gsm;
3063 tty_port_tty_set(port, tty);
3066 /* We could in theory open and close before we wait - eg if we get
3067 a DM straight back. This is ok as that will have caused a hangup */
3068 tty_port_set_initialized(port, 1);
3069 /* Start sending off SABM messages */
3071 gsm_dlci_begin_open(dlci);
3072 /* And wait for virtual carrier */
3073 return tty_port_block_til_ready(port, tty, filp);
3076 static void gsmtty_close(struct tty_struct *tty, struct file *filp)
3078 struct gsm_dlci *dlci = tty->driver_data;
3082 if (dlci->state == DLCI_CLOSED)
3084 mutex_lock(&dlci->mutex);
3085 gsm_destroy_network(dlci);
3086 mutex_unlock(&dlci->mutex);
3087 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
3089 gsm_dlci_begin_close(dlci);
3090 if (tty_port_initialized(&dlci->port) && C_HUPCL(tty))
3091 tty_port_lower_dtr_rts(&dlci->port);
3092 tty_port_close_end(&dlci->port, tty);
3093 tty_port_tty_set(&dlci->port, NULL);
3097 static void gsmtty_hangup(struct tty_struct *tty)
3099 struct gsm_dlci *dlci = tty->driver_data;
3100 if (dlci->state == DLCI_CLOSED)
3102 tty_port_hangup(&dlci->port);
3103 gsm_dlci_begin_close(dlci);
3106 static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf,
3110 struct gsm_dlci *dlci = tty->driver_data;
3111 if (dlci->state == DLCI_CLOSED)
3113 /* Stuff the bytes into the fifo queue */
3114 sent = kfifo_in_locked(&dlci->fifo, buf, len, &dlci->lock);
3115 /* Need to kick the channel */
3116 gsm_dlci_data_kick(dlci);
3120 static unsigned int gsmtty_write_room(struct tty_struct *tty)
3122 struct gsm_dlci *dlci = tty->driver_data;
3123 if (dlci->state == DLCI_CLOSED)
3125 return TX_SIZE - kfifo_len(&dlci->fifo);
3128 static unsigned int gsmtty_chars_in_buffer(struct tty_struct *tty)
3130 struct gsm_dlci *dlci = tty->driver_data;
3131 if (dlci->state == DLCI_CLOSED)
3133 return kfifo_len(&dlci->fifo);
3136 static void gsmtty_flush_buffer(struct tty_struct *tty)
3138 struct gsm_dlci *dlci = tty->driver_data;
3139 if (dlci->state == DLCI_CLOSED)
3141 /* Caution needed: If we implement reliable transport classes
3142 then the data being transmitted can't simply be junked once
3143 it has first hit the stack. Until then we can just blow it
3145 kfifo_reset(&dlci->fifo);
3146 /* Need to unhook this DLCI from the transmit queue logic */
3149 static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
3151 /* The FIFO handles the queue so the kernel will do the right
3152 thing waiting on chars_in_buffer before calling us. No work
3156 static int gsmtty_tiocmget(struct tty_struct *tty)
3158 struct gsm_dlci *dlci = tty->driver_data;
3159 if (dlci->state == DLCI_CLOSED)
3161 return dlci->modem_rx;
3164 static int gsmtty_tiocmset(struct tty_struct *tty,
3165 unsigned int set, unsigned int clear)
3167 struct gsm_dlci *dlci = tty->driver_data;
3168 unsigned int modem_tx = dlci->modem_tx;
3170 if (dlci->state == DLCI_CLOSED)
3175 if (modem_tx != dlci->modem_tx) {
3176 dlci->modem_tx = modem_tx;
3177 return gsmtty_modem_update(dlci, 0);
3183 static int gsmtty_ioctl(struct tty_struct *tty,
3184 unsigned int cmd, unsigned long arg)
3186 struct gsm_dlci *dlci = tty->driver_data;
3187 struct gsm_netconfig nc;
3190 if (dlci->state == DLCI_CLOSED)
3193 case GSMIOC_ENABLE_NET:
3194 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc)))
3196 nc.if_name[IFNAMSIZ-1] = '\0';
3197 /* return net interface index or error code */
3198 mutex_lock(&dlci->mutex);
3199 index = gsm_create_network(dlci, &nc);
3200 mutex_unlock(&dlci->mutex);
3201 if (copy_to_user((void __user *)arg, &nc, sizeof(nc)))
3204 case GSMIOC_DISABLE_NET:
3205 if (!capable(CAP_NET_ADMIN))
3207 mutex_lock(&dlci->mutex);
3208 gsm_destroy_network(dlci);
3209 mutex_unlock(&dlci->mutex);
3212 return -ENOIOCTLCMD;
3216 static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old)
3218 struct gsm_dlci *dlci = tty->driver_data;
3219 if (dlci->state == DLCI_CLOSED)
3221 /* For the moment its fixed. In actual fact the speed information
3222 for the virtual channel can be propogated in both directions by
3223 the RPN control message. This however rapidly gets nasty as we
3224 then have to remap modem signals each way according to whether
3225 our virtual cable is null modem etc .. */
3226 tty_termios_copy_hw(&tty->termios, old);
3229 static void gsmtty_throttle(struct tty_struct *tty)
3231 struct gsm_dlci *dlci = tty->driver_data;
3232 if (dlci->state == DLCI_CLOSED)
3235 dlci->modem_tx &= ~TIOCM_DTR;
3236 dlci->throttled = true;
3237 /* Send an MSC with DTR cleared */
3238 gsmtty_modem_update(dlci, 0);
3241 static void gsmtty_unthrottle(struct tty_struct *tty)
3243 struct gsm_dlci *dlci = tty->driver_data;
3244 if (dlci->state == DLCI_CLOSED)
3247 dlci->modem_tx |= TIOCM_DTR;
3248 dlci->throttled = false;
3249 /* Send an MSC with DTR set */
3250 gsmtty_modem_update(dlci, 0);
3253 static int gsmtty_break_ctl(struct tty_struct *tty, int state)
3255 struct gsm_dlci *dlci = tty->driver_data;
3256 int encode = 0; /* Off */
3257 if (dlci->state == DLCI_CLOSED)
3260 if (state == -1) /* "On indefinitely" - we can't encode this
3263 else if (state > 0) {
3264 encode = state / 200; /* mS to encoding */
3266 encode = 0x0F; /* Best effort */
3268 return gsmtty_modem_update(dlci, encode);
3271 static void gsmtty_cleanup(struct tty_struct *tty)
3273 struct gsm_dlci *dlci = tty->driver_data;
3274 struct gsm_mux *gsm = dlci->gsm;
3277 dlci_put(gsm->dlci[0]);
3281 /* Virtual ttys for the demux */
3282 static const struct tty_operations gsmtty_ops = {
3283 .install = gsmtty_install,
3284 .open = gsmtty_open,
3285 .close = gsmtty_close,
3286 .write = gsmtty_write,
3287 .write_room = gsmtty_write_room,
3288 .chars_in_buffer = gsmtty_chars_in_buffer,
3289 .flush_buffer = gsmtty_flush_buffer,
3290 .ioctl = gsmtty_ioctl,
3291 .throttle = gsmtty_throttle,
3292 .unthrottle = gsmtty_unthrottle,
3293 .set_termios = gsmtty_set_termios,
3294 .hangup = gsmtty_hangup,
3295 .wait_until_sent = gsmtty_wait_until_sent,
3296 .tiocmget = gsmtty_tiocmget,
3297 .tiocmset = gsmtty_tiocmset,
3298 .break_ctl = gsmtty_break_ctl,
3299 .cleanup = gsmtty_cleanup,
3304 static int __init gsm_init(void)
3306 /* Fill in our line protocol discipline, and register it */
3307 int status = tty_register_ldisc(&tty_ldisc_packet);
3309 pr_err("n_gsm: can't register line discipline (err = %d)\n",
3314 gsm_tty_driver = tty_alloc_driver(256, TTY_DRIVER_REAL_RAW |
3315 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_HARDWARE_BREAK);
3316 if (IS_ERR(gsm_tty_driver)) {
3317 pr_err("gsm_init: tty allocation failed.\n");
3318 status = PTR_ERR(gsm_tty_driver);
3319 goto err_unreg_ldisc;
3321 gsm_tty_driver->driver_name = "gsmtty";
3322 gsm_tty_driver->name = "gsmtty";
3323 gsm_tty_driver->major = 0; /* Dynamic */
3324 gsm_tty_driver->minor_start = 0;
3325 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
3326 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
3327 gsm_tty_driver->init_termios = tty_std_termios;
3329 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
3330 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
3332 if (tty_register_driver(gsm_tty_driver)) {
3333 pr_err("gsm_init: tty registration failed.\n");
3335 goto err_put_driver;
3337 pr_debug("gsm_init: loaded as %d,%d.\n",
3338 gsm_tty_driver->major, gsm_tty_driver->minor_start);
3341 tty_driver_kref_put(gsm_tty_driver);
3343 tty_unregister_ldisc(&tty_ldisc_packet);
3347 static void __exit gsm_exit(void)
3349 tty_unregister_ldisc(&tty_ldisc_packet);
3350 tty_unregister_driver(gsm_tty_driver);
3351 tty_driver_kref_put(gsm_tty_driver);
3354 module_init(gsm_init);
3355 module_exit(gsm_exit);
3358 MODULE_LICENSE("GPL");
3359 MODULE_ALIAS_LDISC(N_GSM0710);