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
325 #define ISO_IEC_646_MASK 0x7F
327 static const struct tty_port_operations gsm_port_ops;
330 * CRC table for GSM 0710
333 static const u8 gsm_fcs8[256] = {
334 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75,
335 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B,
336 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69,
337 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67,
338 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D,
339 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43,
340 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51,
341 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F,
342 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05,
343 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B,
344 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19,
345 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17,
346 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D,
347 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33,
348 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21,
349 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F,
350 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95,
351 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B,
352 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89,
353 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87,
354 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD,
355 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3,
356 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1,
357 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF,
358 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5,
359 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB,
360 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9,
361 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7,
362 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD,
363 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3,
364 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1,
365 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF
368 #define INIT_FCS 0xFF
369 #define GOOD_FCS 0xCF
371 static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len);
374 * gsm_fcs_add - update FCS
378 * Update the FCS to include c. Uses the algorithm in the specification
382 static inline u8 gsm_fcs_add(u8 fcs, u8 c)
384 return gsm_fcs8[fcs ^ c];
388 * gsm_fcs_add_block - update FCS for a block
391 * @len: length of buffer
393 * Update the FCS to include c. Uses the algorithm in the specification
397 static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len)
400 fcs = gsm_fcs8[fcs ^ *c++];
405 * gsm_read_ea - read a byte into an EA
406 * @val: variable holding value
407 * @c: byte going into the EA
409 * Processes one byte of an EA. Updates the passed variable
410 * and returns 1 if the EA is now completely read
413 static int gsm_read_ea(unsigned int *val, u8 c)
415 /* Add the next 7 bits into the value */
418 /* Was this the last byte of the EA 1 = yes*/
423 * gsm_encode_modem - encode modem data bits
424 * @dlci: DLCI to encode from
426 * Returns the correct GSM encoded modem status bits (6 bit field) for
427 * the current status of the DLCI and attached tty object
430 static u8 gsm_encode_modem(const struct gsm_dlci *dlci)
433 /* FC is true flow control not modem bits */
436 if (dlci->modem_tx & TIOCM_DTR)
437 modembits |= MDM_RTC;
438 if (dlci->modem_tx & TIOCM_RTS)
439 modembits |= MDM_RTR;
440 if (dlci->modem_tx & TIOCM_RI)
442 if (dlci->modem_tx & TIOCM_CD || dlci->gsm->initiator)
448 * gsm_print_packet - display a frame for debug
449 * @hdr: header to print before decode
450 * @addr: address EA from the frame
451 * @cr: C/R bit seen as initiator
452 * @control: control including PF bit
453 * @data: following data bytes
454 * @dlen: length of data
456 * Displays a packet in human readable format for debugging purposes. The
457 * style is based on amateur radio LAP-B dump display.
460 static void gsm_print_packet(const char *hdr, int addr, int cr,
461 u8 control, const u8 *data, int dlen)
466 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]);
468 switch (control & ~PF) {
488 if (!(control & 0x01)) {
489 pr_cont("I N(S)%d N(R)%d",
490 (control & 0x0E) >> 1, (control & 0xE0) >> 5);
491 } else switch (control & 0x0F) {
493 pr_cont("RR(%d)", (control & 0xE0) >> 5);
496 pr_cont("RNR(%d)", (control & 0xE0) >> 5);
499 pr_cont("REJ(%d)", (control & 0xE0) >> 5);
502 pr_cont("[%02X]", control);
511 print_hex_dump_bytes("", DUMP_PREFIX_NONE, data, dlen);
516 * Link level transmission side
520 * gsm_stuff_frame - bytestuff a packet
521 * @input: input buffer
522 * @output: output buffer
523 * @len: length of input
525 * Expand a buffer by bytestuffing it. The worst case size change
526 * is doubling and the caller is responsible for handing out
527 * suitable sized buffers.
530 static int gsm_stuff_frame(const u8 *input, u8 *output, int len)
534 if (*input == GSM1_SOF || *input == GSM1_ESCAPE
535 || (*input & ISO_IEC_646_MASK) == XON
536 || (*input & ISO_IEC_646_MASK) == XOFF) {
537 *output++ = GSM1_ESCAPE;
538 *output++ = *input++ ^ GSM1_ESCAPE_BITS;
541 *output++ = *input++;
548 * gsm_send - send a control frame
550 * @addr: address for control frame
551 * @cr: command/response bit seen as initiator
552 * @control: control byte including PF bit
554 * Format up and transmit a control frame. These do not go via the
555 * queueing logic as they should be transmitted ahead of data when
558 * FIXME: Lock versus data TX path
561 static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control)
568 /* toggle C/R coding if not initiator */
569 ocr = cr ^ (gsm->initiator ? 0 : 1);
571 switch (gsm->encoding) {
574 cbuf[1] = (addr << 2) | (ocr << 1) | EA;
576 cbuf[3] = EA; /* Length of data = 0 */
577 cbuf[4] = 0xFF - gsm_fcs_add_block(INIT_FCS, cbuf + 1, 3);
583 /* Control frame + packing (but not frame stuffing) in mode 1 */
584 ibuf[0] = (addr << 2) | (ocr << 1) | EA;
586 ibuf[2] = 0xFF - gsm_fcs_add_block(INIT_FCS, ibuf, 2);
587 /* Stuffing may double the size worst case */
588 len = gsm_stuff_frame(ibuf, cbuf + 1, 3);
589 /* Now add the SOF markers */
591 cbuf[len + 1] = GSM1_SOF;
592 /* FIXME: we can omit the lead one in many cases */
599 gsmld_output(gsm, cbuf, len);
600 if (!gsm->initiator) {
601 cr = cr & gsm->initiator;
602 control = control & ~PF;
604 gsm_print_packet("-->", addr, cr, control, NULL, 0);
608 * gsm_response - send a control response
610 * @addr: address for control frame
611 * @control: control byte including PF bit
613 * Format up and transmit a link level response frame.
616 static inline void gsm_response(struct gsm_mux *gsm, int addr, int control)
618 gsm_send(gsm, addr, 0, control);
622 * gsm_command - send a control command
624 * @addr: address for control frame
625 * @control: control byte including PF bit
627 * Format up and transmit a link level command frame.
630 static inline void gsm_command(struct gsm_mux *gsm, int addr, int control)
632 gsm_send(gsm, addr, 1, control);
635 /* Data transmission */
637 #define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */
640 * gsm_data_alloc - allocate data frame
642 * @addr: DLCI address
643 * @len: length excluding header and FCS
644 * @ctrl: control byte
646 * Allocate a new data buffer for sending frames with data. Space is left
647 * at the front for header bytes but that is treated as an implementation
648 * detail and not for the high level code to use
651 static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
654 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN,
658 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */
662 INIT_LIST_HEAD(&m->list);
667 * gsm_data_kick - poke the queue
669 * @dlci: DLCI sending the data
671 * The tty device has called us to indicate that room has appeared in
672 * the transmit queue. Ram more data into the pipe if we have any
673 * If we have been flow-stopped by a CMD_FCOFF, then we can only
674 * send messages on DLCI0 until CMD_FCON
676 * FIXME: lock against link layer control transmissions
679 static void gsm_data_kick(struct gsm_mux *gsm, struct gsm_dlci *dlci)
681 struct gsm_msg *msg, *nmsg;
684 list_for_each_entry_safe(msg, nmsg, &gsm->tx_list, list) {
685 if (gsm->constipated && msg->addr)
687 if (gsm->encoding != 0) {
688 gsm->txframe[0] = GSM1_SOF;
689 len = gsm_stuff_frame(msg->data,
690 gsm->txframe + 1, msg->len);
691 gsm->txframe[len + 1] = GSM1_SOF;
694 gsm->txframe[0] = GSM0_SOF;
695 memcpy(gsm->txframe + 1 , msg->data, msg->len);
696 gsm->txframe[msg->len + 1] = GSM0_SOF;
701 print_hex_dump_bytes("gsm_data_kick: ",
704 if (gsmld_output(gsm, gsm->txframe, len) <= 0)
706 /* FIXME: Can eliminate one SOF in many more cases */
707 gsm->tx_bytes -= msg->len;
709 list_del(&msg->list);
713 tty_port_tty_wakeup(&dlci->port);
717 for (i = 0; i < NUM_DLCI; i++)
719 tty_port_tty_wakeup(&gsm->dlci[i]->port);
725 * __gsm_data_queue - queue a UI or UIH frame
726 * @dlci: DLCI sending the data
727 * @msg: message queued
729 * Add data to the transmit queue and try and get stuff moving
730 * out of the mux tty if not already doing so. The Caller must hold
734 static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
736 struct gsm_mux *gsm = dlci->gsm;
738 u8 *fcs = dp + msg->len;
740 /* Fill in the header */
741 if (gsm->encoding == 0) {
743 *--dp = (msg->len << 1) | EA;
745 *--dp = (msg->len >> 7); /* bits 7 - 15 */
746 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */
752 *--dp = (msg->addr << 2) | 2 | EA;
754 *--dp = (msg->addr << 2) | EA;
755 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp);
756 /* Ugly protocol layering violation */
757 if (msg->ctrl == UI || msg->ctrl == (UI|PF))
758 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len);
761 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl,
762 msg->data, msg->len);
764 /* Move the header back and adjust the length, also allow for the FCS
765 now tacked on the end */
766 msg->len += (msg->data - dp) + 1;
769 /* Add to the actual output queue */
770 list_add_tail(&msg->list, &gsm->tx_list);
771 gsm->tx_bytes += msg->len;
772 gsm_data_kick(gsm, dlci);
776 * gsm_data_queue - queue a UI or UIH frame
777 * @dlci: DLCI sending the data
778 * @msg: message queued
780 * Add data to the transmit queue and try and get stuff moving
781 * out of the mux tty if not already doing so. Take the
782 * the gsm tx lock and dlci lock.
785 static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
788 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
789 __gsm_data_queue(dlci, msg);
790 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
794 * gsm_dlci_data_output - try and push data out of a DLCI
796 * @dlci: the DLCI to pull data from
798 * Pull data from a DLCI and send it into the transmit queue if there
799 * is data. Keep to the MRU of the mux. This path handles the usual tty
800 * interface which is a byte stream with optional modem data.
802 * Caller must hold the tx_lock of the mux.
805 static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci)
809 int len, total_size, size;
810 int h = dlci->adaption - 1;
814 len = kfifo_len(&dlci->fifo);
818 /* MTU/MRU count only the data bits */
824 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
825 /* FIXME: need a timer or something to kick this so it can't
826 get stuck with no work outstanding and no buffer free */
830 switch (dlci->adaption) {
831 case 1: /* Unstructured */
833 case 2: /* Unstructed with modem bits.
834 Always one byte as we never send inline break data */
835 *dp++ = gsm_encode_modem(dlci);
838 WARN_ON(kfifo_out_locked(&dlci->fifo, dp , len, &dlci->lock) != len);
839 __gsm_data_queue(dlci, msg);
842 /* Bytes of data we used up */
847 * gsm_dlci_data_output_framed - try and push data out of a DLCI
849 * @dlci: the DLCI to pull data from
851 * Pull data from a DLCI and send it into the transmit queue if there
852 * is data. Keep to the MRU of the mux. This path handles framed data
853 * queued as skbuffs to the DLCI.
855 * Caller must hold the tx_lock of the mux.
858 static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
859 struct gsm_dlci *dlci)
864 int last = 0, first = 0;
867 /* One byte per frame is used for B/F flags */
868 if (dlci->adaption == 4)
871 /* dlci->skb is locked by tx_lock */
872 if (dlci->skb == NULL) {
873 dlci->skb = skb_dequeue_tail(&dlci->skb_list);
874 if (dlci->skb == NULL)
878 len = dlci->skb->len + overhead;
880 /* MTU/MRU count only the data bits */
881 if (len > gsm->mtu) {
882 if (dlci->adaption == 3) {
883 /* Over long frame, bin it */
884 dev_kfree_skb_any(dlci->skb);
892 size = len + overhead;
893 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
895 /* FIXME: need a timer or something to kick this so it can't
896 get stuck with no work outstanding and no buffer free */
898 skb_queue_tail(&dlci->skb_list, dlci->skb);
904 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */
905 /* Flag byte to carry the start/end info */
906 *dp++ = last << 7 | first << 6 | 1; /* EA */
909 memcpy(dp, dlci->skb->data, len);
910 skb_pull(dlci->skb, len);
911 __gsm_data_queue(dlci, msg);
913 dev_kfree_skb_any(dlci->skb);
920 * gsm_dlci_data_sweep - look for data to send
923 * Sweep the GSM mux channels in priority order looking for ones with
924 * data to send. We could do with optimising this scan a bit. We aim
925 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit
926 * TX_THRESH_LO we get called again
928 * FIXME: We should round robin between groups and in theory you can
929 * renegotiate DLCI priorities with optional stuff. Needs optimising.
932 static void gsm_dlci_data_sweep(struct gsm_mux *gsm)
935 /* Priority ordering: We should do priority with RR of the groups */
938 while (i < NUM_DLCI) {
939 struct gsm_dlci *dlci;
941 if (gsm->tx_bytes > TX_THRESH_HI)
944 if (dlci == NULL || dlci->constipated) {
948 if (dlci->adaption < 3 && !dlci->net)
949 len = gsm_dlci_data_output(gsm, dlci);
951 len = gsm_dlci_data_output_framed(gsm, dlci);
954 /* DLCI empty - try the next */
961 * gsm_dlci_data_kick - transmit if possible
962 * @dlci: DLCI to kick
964 * Transmit data from this DLCI if the queue is empty. We can't rely on
965 * a tty wakeup except when we filled the pipe so we need to fire off
966 * new data ourselves in other cases.
969 static void gsm_dlci_data_kick(struct gsm_dlci *dlci)
974 if (dlci->constipated)
977 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
978 /* If we have nothing running then we need to fire up */
979 sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO);
980 if (dlci->gsm->tx_bytes == 0) {
982 gsm_dlci_data_output_framed(dlci->gsm, dlci);
984 gsm_dlci_data_output(dlci->gsm, dlci);
987 gsm_dlci_data_sweep(dlci->gsm);
988 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
992 * Control message processing
997 * gsm_control_reply - send a response frame to a control
999 * @cmd: the command to use
1000 * @data: data to follow encoded info
1001 * @dlen: length of data
1003 * Encode up and queue a UI/UIH frame containing our response.
1006 static void gsm_control_reply(struct gsm_mux *gsm, int cmd, const u8 *data,
1009 struct gsm_msg *msg;
1010 msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype);
1013 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */
1014 msg->data[1] = (dlen << 1) | EA;
1015 memcpy(msg->data + 2, data, dlen);
1016 gsm_data_queue(gsm->dlci[0], msg);
1020 * gsm_process_modem - process received modem status
1021 * @tty: virtual tty bound to the DLCI
1022 * @dlci: DLCI to affect
1023 * @modem: modem bits (full EA)
1024 * @clen: command length
1026 * Used when a modem control message or line state inline in adaption
1027 * layer 2 is processed. Sort out the local modem state and throttles
1030 static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
1031 u32 modem, int clen)
1037 /* The modem status command can either contain one octet (v.24 signals)
1038 or two octets (v.24 signals + break signals). The length field will
1039 either be 2 or 3 respectively. This is specified in section
1040 5.4.6.3.7 of the 27.010 mux spec. */
1043 modem = modem & 0x7f;
1046 modem = (modem >> 7) & 0x7f;
1049 /* Flow control/ready to communicate */
1050 fc = (modem & MDM_FC) || !(modem & MDM_RTR);
1051 if (fc && !dlci->constipated) {
1052 /* Need to throttle our output on this device */
1053 dlci->constipated = true;
1054 } else if (!fc && dlci->constipated) {
1055 dlci->constipated = false;
1056 gsm_dlci_data_kick(dlci);
1059 /* Map modem bits */
1060 if (modem & MDM_RTC)
1061 mlines |= TIOCM_DSR | TIOCM_DTR;
1062 if (modem & MDM_RTR)
1063 mlines |= TIOCM_RTS | TIOCM_CTS;
1069 /* Carrier drop -> hangup */
1071 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD))
1076 tty_insert_flip_char(&dlci->port, 0, TTY_BREAK);
1077 dlci->modem_rx = mlines;
1081 * gsm_control_modem - modem status received
1083 * @data: data following command
1084 * @clen: command length
1086 * We have received a modem status control message. This is used by
1087 * the GSM mux protocol to pass virtual modem line status and optionally
1088 * to indicate break signals. Unpack it, convert to Linux representation
1089 * and if need be stuff a break message down the tty.
1092 static void gsm_control_modem(struct gsm_mux *gsm, const u8 *data, int clen)
1094 unsigned int addr = 0;
1095 unsigned int modem = 0;
1096 unsigned int brk = 0;
1097 struct gsm_dlci *dlci;
1099 const u8 *dp = data;
1100 struct tty_struct *tty;
1102 while (gsm_read_ea(&addr, *dp++) == 0) {
1107 /* Must be at least one byte following the EA */
1113 /* Closed port, or invalid ? */
1114 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1116 dlci = gsm->dlci[addr];
1118 while (gsm_read_ea(&modem, *dp++) == 0) {
1125 while (gsm_read_ea(&brk, *dp++) == 0) {
1131 modem |= (brk & 0x7f);
1133 tty = tty_port_tty_get(&dlci->port);
1134 gsm_process_modem(tty, dlci, modem, clen);
1139 gsm_control_reply(gsm, CMD_MSC, data, clen);
1143 * gsm_control_rls - remote line status
1146 * @clen: data length
1148 * The modem sends us a two byte message on the control channel whenever
1149 * it wishes to send us an error state from the virtual link. Stuff
1150 * this into the uplink tty if present
1153 static void gsm_control_rls(struct gsm_mux *gsm, const u8 *data, int clen)
1155 struct tty_port *port;
1156 unsigned int addr = 0;
1159 const u8 *dp = data;
1161 while (gsm_read_ea(&addr, *dp++) == 0) {
1166 /* Must be at least one byte following ea */
1171 /* Closed port, or invalid ? */
1172 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1176 if ((bits & 1) == 0)
1179 port = &gsm->dlci[addr]->port;
1182 tty_insert_flip_char(port, 0, TTY_OVERRUN);
1184 tty_insert_flip_char(port, 0, TTY_PARITY);
1186 tty_insert_flip_char(port, 0, TTY_FRAME);
1188 tty_flip_buffer_push(port);
1190 gsm_control_reply(gsm, CMD_RLS, data, clen);
1193 static void gsm_dlci_begin_close(struct gsm_dlci *dlci);
1194 static void gsm_dlci_close(struct gsm_dlci *dlci);
1197 * gsm_control_message - DLCI 0 control processing
1199 * @command: the command EA
1200 * @data: data beyond the command/length EAs
1203 * Input processor for control messages from the other end of the link.
1204 * Processes the incoming request and queues a response frame or an
1205 * NSC response if not supported
1208 static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
1209 const u8 *data, int clen)
1212 unsigned long flags;
1213 struct gsm_dlci *dlci;
1220 for (i = 0; i < addr_cnt; i++) {
1221 address = addr_open[i];
1222 dlci = gsm->dlci[address];
1223 gsm_dlci_close(dlci);
1227 /* Modem wishes to close down */
1228 dlci = gsm->dlci[0];
1232 gsm_dlci_close(dlci);
1234 gsm_response(gsm, 0, UA|PF);
1239 /* Modem wishes to test, reply with the data */
1240 gsm_control_reply(gsm, CMD_TEST, data, clen);
1243 /* Modem can accept data again */
1244 gsm->constipated = false;
1245 gsm_control_reply(gsm, CMD_FCON, NULL, 0);
1246 /* Kick the link in case it is idling */
1247 spin_lock_irqsave(&gsm->tx_lock, flags);
1248 gsm_data_kick(gsm, NULL);
1249 spin_unlock_irqrestore(&gsm->tx_lock, flags);
1252 /* Modem wants us to STFU */
1253 gsm->constipated = true;
1254 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0);
1257 /* Out of band modem line change indicator for a DLCI */
1258 gsm_control_modem(gsm, data, clen);
1261 /* Out of band error reception for a DLCI */
1262 gsm_control_rls(gsm, data, clen);
1265 /* Modem wishes to enter power saving state */
1266 gsm_control_reply(gsm, CMD_PSC, NULL, 0);
1268 /* Optional unsupported commands */
1269 case CMD_PN: /* Parameter negotiation */
1270 case CMD_RPN: /* Remote port negotiation */
1271 case CMD_SNC: /* Service negotiation command */
1273 /* Reply to bad commands with an NSC */
1275 gsm_control_reply(gsm, CMD_NSC, buf, 1);
1281 * gsm_control_response - process a response to our control
1283 * @command: the command (response) EA
1284 * @data: data beyond the command/length EA
1287 * Process a response to an outstanding command. We only allow a single
1288 * control message in flight so this is fairly easy. All the clean up
1289 * is done by the caller, we just update the fields, flag it as done
1293 static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
1294 const u8 *data, int clen)
1296 struct gsm_control *ctrl;
1297 unsigned long flags;
1299 spin_lock_irqsave(&gsm->control_lock, flags);
1301 ctrl = gsm->pending_cmd;
1302 /* Does the reply match our command */
1304 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) {
1305 /* Our command was replied to, kill the retry timer */
1306 del_timer(&gsm->t2_timer);
1307 gsm->pending_cmd = NULL;
1308 /* Rejected by the other end */
1309 if (command == CMD_NSC)
1310 ctrl->error = -EOPNOTSUPP;
1312 wake_up(&gsm->event);
1314 spin_unlock_irqrestore(&gsm->control_lock, flags);
1318 * gsm_control_transmit - send control packet
1320 * @ctrl: frame to send
1322 * Send out a pending control command (called under control lock)
1325 static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl)
1327 struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, gsm->ftype);
1330 msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */
1331 memcpy(msg->data + 1, ctrl->data, ctrl->len);
1332 gsm_data_queue(gsm->dlci[0], msg);
1336 * gsm_control_retransmit - retransmit a control frame
1337 * @t: timer contained in our gsm object
1339 * Called off the T2 timer expiry in order to retransmit control frames
1340 * that have been lost in the system somewhere. The control_lock protects
1341 * us from colliding with another sender or a receive completion event.
1342 * In that situation the timer may still occur in a small window but
1343 * gsm->pending_cmd will be NULL and we just let the timer expire.
1346 static void gsm_control_retransmit(struct timer_list *t)
1348 struct gsm_mux *gsm = from_timer(gsm, t, t2_timer);
1349 struct gsm_control *ctrl;
1350 unsigned long flags;
1351 spin_lock_irqsave(&gsm->control_lock, flags);
1352 ctrl = gsm->pending_cmd;
1355 if (gsm->cretries == 0) {
1356 gsm->pending_cmd = NULL;
1357 ctrl->error = -ETIMEDOUT;
1359 spin_unlock_irqrestore(&gsm->control_lock, flags);
1360 wake_up(&gsm->event);
1363 gsm_control_transmit(gsm, ctrl);
1364 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1366 spin_unlock_irqrestore(&gsm->control_lock, flags);
1370 * gsm_control_send - send a control frame on DLCI 0
1371 * @gsm: the GSM channel
1372 * @command: command to send including CR bit
1373 * @data: bytes of data (must be kmalloced)
1374 * @clen: length of the block to send
1376 * Queue and dispatch a control command. Only one command can be
1377 * active at a time. In theory more can be outstanding but the matching
1378 * gets really complicated so for now stick to one outstanding.
1381 static struct gsm_control *gsm_control_send(struct gsm_mux *gsm,
1382 unsigned int command, u8 *data, int clen)
1384 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control),
1386 unsigned long flags;
1390 wait_event(gsm->event, gsm->pending_cmd == NULL);
1391 spin_lock_irqsave(&gsm->control_lock, flags);
1392 if (gsm->pending_cmd != NULL) {
1393 spin_unlock_irqrestore(&gsm->control_lock, flags);
1396 ctrl->cmd = command;
1399 gsm->pending_cmd = ctrl;
1401 /* If DLCI0 is in ADM mode skip retries, it won't respond */
1402 if (gsm->dlci[0]->mode == DLCI_MODE_ADM)
1405 gsm->cretries = gsm->n2;
1407 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1408 gsm_control_transmit(gsm, ctrl);
1409 spin_unlock_irqrestore(&gsm->control_lock, flags);
1414 * gsm_control_wait - wait for a control to finish
1416 * @control: control we are waiting on
1418 * Waits for the control to complete or time out. Frees any used
1419 * resources and returns 0 for success, or an error if the remote
1420 * rejected or ignored the request.
1423 static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
1426 wait_event(gsm->event, control->done == 1);
1427 err = control->error;
1434 * DLCI level handling: Needs krefs
1438 * State transitions and timers
1442 * gsm_dlci_close - a DLCI has closed
1443 * @dlci: DLCI that closed
1445 * Perform processing when moving a DLCI into closed state. If there
1446 * is an attached tty this is hung up
1449 static void gsm_dlci_close(struct gsm_dlci *dlci)
1451 del_timer(&dlci->t1);
1453 pr_debug("DLCI %d goes closed.\n", dlci->addr);
1454 dlci->state = DLCI_CLOSED;
1455 if (dlci->addr != 0) {
1456 tty_port_tty_hangup(&dlci->port, false);
1457 kfifo_reset(&dlci->fifo);
1459 dlci->gsm->dead = true;
1460 /* Unregister gsmtty driver,report gsmtty dev remove uevent for user */
1461 tty_unregister_device(gsm_tty_driver, dlci->addr);
1462 wake_up(&dlci->gsm->event);
1463 /* A DLCI 0 close is a MUX termination so we need to kick that
1464 back to userspace somehow */
1468 * gsm_dlci_open - a DLCI has opened
1469 * @dlci: DLCI that opened
1471 * Perform processing when moving a DLCI into open state.
1474 static void gsm_dlci_open(struct gsm_dlci *dlci)
1476 /* Note that SABM UA .. SABM UA first UA lost can mean that we go
1478 del_timer(&dlci->t1);
1479 /* This will let a tty open continue */
1480 dlci->state = DLCI_OPEN;
1482 pr_debug("DLCI %d goes open.\n", dlci->addr);
1483 /* Register gsmtty driver,report gsmtty dev add uevent for user */
1484 tty_register_device(gsm_tty_driver, dlci->addr, NULL);
1485 wake_up(&dlci->gsm->event);
1489 * gsm_dlci_t1 - T1 timer expiry
1490 * @t: timer contained in the DLCI that opened
1492 * The T1 timer handles retransmits of control frames (essentially of
1493 * SABM and DISC). We resend the command until the retry count runs out
1494 * in which case an opening port goes back to closed and a closing port
1495 * is simply put into closed state (any further frames from the other
1496 * end will get a DM response)
1498 * Some control dlci can stay in ADM mode with other dlci working just
1499 * fine. In that case we can just keep the control dlci open after the
1500 * DLCI_OPENING retries time out.
1503 static void gsm_dlci_t1(struct timer_list *t)
1505 struct gsm_dlci *dlci = from_timer(dlci, t, t1);
1506 struct gsm_mux *gsm = dlci->gsm;
1508 switch (dlci->state) {
1511 if (dlci->retries) {
1512 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1513 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1514 } else if (!dlci->addr && gsm->control == (DM | PF)) {
1516 pr_info("DLCI %d opening in ADM mode.\n",
1518 dlci->mode = DLCI_MODE_ADM;
1519 gsm_dlci_open(dlci);
1521 gsm_dlci_begin_close(dlci); /* prevent half open link */
1527 if (dlci->retries) {
1528 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1529 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1531 gsm_dlci_close(dlci);
1534 pr_debug("%s: unhandled state: %d\n", __func__, dlci->state);
1540 * gsm_dlci_begin_open - start channel open procedure
1541 * @dlci: DLCI to open
1543 * Commence opening a DLCI from the Linux side. We issue SABM messages
1544 * to the modem which should then reply with a UA or ADM, at which point
1545 * we will move into open state. Opening is done asynchronously with retry
1546 * running off timers and the responses.
1549 static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
1551 struct gsm_mux *gsm = dlci->gsm;
1552 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING)
1554 dlci->retries = gsm->n2;
1555 dlci->state = DLCI_OPENING;
1556 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1557 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1561 * gsm_dlci_begin_close - start channel open procedure
1562 * @dlci: DLCI to open
1564 * Commence closing a DLCI from the Linux side. We issue DISC messages
1565 * to the modem which should then reply with a UA, at which point we
1566 * will move into closed state. Closing is done asynchronously with retry
1567 * off timers. We may also receive a DM reply from the other end which
1568 * indicates the channel was already closed.
1571 static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
1573 struct gsm_mux *gsm = dlci->gsm;
1574 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
1576 dlci->retries = gsm->n2;
1577 dlci->state = DLCI_CLOSING;
1578 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1579 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1583 * gsm_dlci_data - data arrived
1585 * @data: block of bytes received
1586 * @clen: length of received block
1588 * A UI or UIH frame has arrived which contains data for a channel
1589 * other than the control channel. If the relevant virtual tty is
1590 * open we shovel the bits down it, if not we drop them.
1593 static void gsm_dlci_data(struct gsm_dlci *dlci, const u8 *data, int clen)
1596 struct tty_port *port = &dlci->port;
1597 struct tty_struct *tty;
1598 unsigned int modem = 0;
1602 pr_debug("%d bytes for tty\n", len);
1603 switch (dlci->adaption) {
1604 /* Unsupported types */
1605 case 4: /* Packetised interruptible data */
1607 case 3: /* Packetised uininterruptible voice/data */
1609 case 2: /* Asynchronous serial with line state in each frame */
1610 while (gsm_read_ea(&modem, *data++) == 0) {
1615 tty = tty_port_tty_get(port);
1617 gsm_process_modem(tty, dlci, modem, clen);
1621 case 1: /* Line state will go via DLCI 0 controls only */
1623 tty_insert_flip_string(port, data, len);
1624 tty_flip_buffer_push(port);
1629 * gsm_dlci_command - data arrived on control channel
1631 * @data: block of bytes received
1632 * @len: length of received block
1634 * A UI or UIH frame has arrived which contains data for DLCI 0 the
1635 * control channel. This should contain a command EA followed by
1636 * control data bytes. The command EA contains a command/response bit
1637 * and we divide up the work accordingly.
1640 static void gsm_dlci_command(struct gsm_dlci *dlci, const u8 *data, int len)
1642 /* See what command is involved */
1643 unsigned int command = 0;
1645 if (gsm_read_ea(&command, *data++) == 1) {
1648 /* FIXME: this is properly an EA */
1650 /* Malformed command ? */
1654 gsm_control_message(dlci->gsm, command,
1657 gsm_control_response(dlci->gsm, command,
1665 * Allocate/Free DLCI channels
1669 * gsm_dlci_alloc - allocate a DLCI
1671 * @addr: address of the DLCI
1673 * Allocate and install a new DLCI object into the GSM mux.
1675 * FIXME: review locking races
1678 static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
1680 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC);
1683 spin_lock_init(&dlci->lock);
1684 mutex_init(&dlci->mutex);
1685 if (kfifo_alloc(&dlci->fifo, 4096, GFP_KERNEL) < 0) {
1690 skb_queue_head_init(&dlci->skb_list);
1691 timer_setup(&dlci->t1, gsm_dlci_t1, 0);
1692 tty_port_init(&dlci->port);
1693 dlci->port.ops = &gsm_port_ops;
1696 dlci->adaption = gsm->adaption;
1697 dlci->state = DLCI_CLOSED;
1699 dlci->data = gsm_dlci_data;
1701 dlci->data = gsm_dlci_command;
1702 gsm->dlci[addr] = dlci;
1707 * gsm_dlci_free - free DLCI
1708 * @port: tty port for DLCI to free
1714 static void gsm_dlci_free(struct tty_port *port)
1716 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
1718 del_timer_sync(&dlci->t1);
1719 dlci->gsm->dlci[dlci->addr] = NULL;
1720 kfifo_free(&dlci->fifo);
1721 while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
1722 dev_kfree_skb(dlci->skb);
1726 static inline void dlci_get(struct gsm_dlci *dlci)
1728 tty_port_get(&dlci->port);
1731 static inline void dlci_put(struct gsm_dlci *dlci)
1733 tty_port_put(&dlci->port);
1736 static void gsm_destroy_network(struct gsm_dlci *dlci);
1739 * gsm_dlci_release - release DLCI
1740 * @dlci: DLCI to destroy
1742 * Release a DLCI. Actual free is deferred until either
1743 * mux is closed or tty is closed - whichever is last.
1747 static void gsm_dlci_release(struct gsm_dlci *dlci)
1749 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1751 mutex_lock(&dlci->mutex);
1752 gsm_destroy_network(dlci);
1753 mutex_unlock(&dlci->mutex);
1755 /* We cannot use tty_hangup() because in tty_kref_put() the tty
1756 * driver assumes that the hangup queue is free and reuses it to
1757 * queue release_one_tty() -> NULL pointer panic in
1758 * process_one_work().
1762 tty_port_tty_set(&dlci->port, NULL);
1765 dlci->state = DLCI_CLOSED;
1770 * LAPBish link layer logic
1774 * gsm_queue - a GSM frame is ready to process
1775 * @gsm: pointer to our gsm mux
1777 * At this point in time a frame has arrived and been demangled from
1778 * the line encoding. All the differences between the encodings have
1779 * been handled below us and the frame is unpacked into the structures.
1780 * The fcs holds the header FCS but any data FCS must be added here.
1783 static void gsm_queue(struct gsm_mux *gsm)
1785 struct gsm_dlci *dlci;
1788 int i, j, k, address_tmp;
1789 /* We have to sneak a look at the packet body to do the FCS.
1790 A somewhat layering violation in the spec */
1792 if ((gsm->control & ~PF) == UI)
1793 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len);
1794 if (gsm->encoding == 0) {
1795 /* WARNING: gsm->received_fcs is used for
1796 gsm->encoding = 0 only.
1797 In this case it contain the last piece of data
1798 required to generate final CRC */
1799 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs);
1801 if (gsm->fcs != GOOD_FCS) {
1804 pr_debug("BAD FCS %02x\n", gsm->fcs);
1807 address = gsm->address >> 1;
1808 if (address >= NUM_DLCI)
1811 cr = gsm->address & 1; /* C/R bit */
1812 cr ^= gsm->initiator ? 0 : 1; /* Flip so 1 always means command */
1814 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
1816 dlci = gsm->dlci[address];
1818 switch (gsm->control) {
1823 dlci = gsm_dlci_alloc(gsm, address);
1827 gsm_response(gsm, address, DM|PF);
1829 gsm_response(gsm, address, UA|PF);
1830 gsm_dlci_open(dlci);
1831 /* Save dlci open address */
1833 addr_open[addr_cnt] = address;
1841 if (dlci == NULL || dlci->state == DLCI_CLOSED) {
1842 gsm_response(gsm, address, DM|PF);
1845 /* Real close complete */
1848 for (i = 0; i < addr_cnt; i++) {
1849 address = addr_open[i];
1850 dlci = gsm->dlci[address];
1851 gsm_dlci_close(dlci);
1855 dlci = gsm->dlci[0];
1856 gsm_dlci_close(dlci);
1858 gsm_response(gsm, 0, UA|PF);
1860 gsm_response(gsm, address, UA|PF);
1861 gsm_dlci_close(dlci);
1862 /* clear dlci address */
1863 for (j = 0; j < addr_cnt; j++) {
1864 address_tmp = addr_open[j];
1865 if (address_tmp == address) {
1866 for (k = j; k < addr_cnt; k++)
1867 addr_open[k] = addr_open[k+1];
1876 if (cr == 0 || dlci == NULL)
1878 switch (dlci->state) {
1880 gsm_dlci_close(dlci);
1883 gsm_dlci_open(dlci);
1886 pr_debug("%s: unhandled state: %d\n", __func__,
1891 case DM: /* DM can be valid unsolicited */
1897 gsm_dlci_close(dlci);
1907 if (dlci == NULL || dlci->state != DLCI_OPEN) {
1908 gsm_command(gsm, address, DM|PF);
1911 dlci->data(dlci, gsm->buf, gsm->len);
1924 * gsm0_receive - perform processing for non-transparency
1925 * @gsm: gsm data for this ldisc instance
1928 * Receive bytes in gsm mode 0
1931 static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
1935 switch (gsm->state) {
1936 case GSM_SEARCH: /* SOF marker */
1937 if (c == GSM0_SOF) {
1938 gsm->state = GSM_ADDRESS;
1941 gsm->fcs = INIT_FCS;
1944 case GSM_ADDRESS: /* Address EA */
1945 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1946 if (gsm_read_ea(&gsm->address, c))
1947 gsm->state = GSM_CONTROL;
1949 case GSM_CONTROL: /* Control Byte */
1950 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1952 gsm->state = GSM_LEN0;
1954 case GSM_LEN0: /* Length EA */
1955 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1956 if (gsm_read_ea(&gsm->len, c)) {
1957 if (gsm->len > gsm->mru) {
1959 gsm->state = GSM_SEARCH;
1964 gsm->state = GSM_FCS;
1966 gsm->state = GSM_DATA;
1969 gsm->state = GSM_LEN1;
1972 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1974 gsm->len |= len << 7;
1975 if (gsm->len > gsm->mru) {
1977 gsm->state = GSM_SEARCH;
1982 gsm->state = GSM_FCS;
1984 gsm->state = GSM_DATA;
1986 case GSM_DATA: /* Data */
1987 gsm->buf[gsm->count++] = c;
1988 if (gsm->count == gsm->len)
1989 gsm->state = GSM_FCS;
1991 case GSM_FCS: /* FCS follows the packet */
1992 gsm->received_fcs = c;
1994 gsm->state = GSM_SSOF;
1997 if (c == GSM0_SOF) {
1998 gsm->state = GSM_SEARCH;
2003 pr_debug("%s: unhandled state: %d\n", __func__, gsm->state);
2009 * gsm1_receive - perform processing for non-transparency
2010 * @gsm: gsm data for this ldisc instance
2013 * Receive bytes in mode 1 (Advanced option)
2016 static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
2018 if (c == GSM1_SOF) {
2019 /* EOF is only valid in frame if we have got to the data state
2020 and received at least one byte (the FCS) */
2021 if (gsm->state == GSM_DATA && gsm->count) {
2022 /* Extract the FCS */
2024 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
2025 gsm->len = gsm->count;
2027 gsm->state = GSM_START;
2030 /* Any partial frame was a runt so go back to start */
2031 if (gsm->state != GSM_START) {
2033 gsm->state = GSM_START;
2035 /* A SOF in GSM_START means we are still reading idling or
2040 if (c == GSM1_ESCAPE) {
2045 /* Only an unescaped SOF gets us out of GSM search */
2046 if (gsm->state == GSM_SEARCH)
2050 c ^= GSM1_ESCAPE_BITS;
2051 gsm->escape = false;
2053 switch (gsm->state) {
2054 case GSM_START: /* First byte after SOF */
2056 gsm->state = GSM_ADDRESS;
2057 gsm->fcs = INIT_FCS;
2059 case GSM_ADDRESS: /* Address continuation */
2060 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2061 if (gsm_read_ea(&gsm->address, c))
2062 gsm->state = GSM_CONTROL;
2064 case GSM_CONTROL: /* Control Byte */
2065 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2068 gsm->state = GSM_DATA;
2070 case GSM_DATA: /* Data */
2071 if (gsm->count > gsm->mru) { /* Allow one for the FCS */
2072 gsm->state = GSM_OVERRUN;
2075 gsm->buf[gsm->count++] = c;
2077 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */
2080 pr_debug("%s: unhandled state: %d\n", __func__, gsm->state);
2086 * gsm_error - handle tty error
2089 * Handle an error in the receipt of data for a frame. Currently we just
2090 * go back to hunting for a SOF.
2092 * FIXME: better diagnostics ?
2095 static void gsm_error(struct gsm_mux *gsm)
2097 gsm->state = GSM_SEARCH;
2101 static int gsm_disconnect(struct gsm_mux *gsm)
2103 struct gsm_dlci *dlci = gsm->dlci[0];
2104 struct gsm_control *gc;
2109 /* In theory disconnecting DLCI 0 is sufficient but for some
2110 modems this is apparently not the case. */
2111 gc = gsm_control_send(gsm, CMD_CLD, NULL, 0);
2113 gsm_control_wait(gsm, gc);
2115 del_timer_sync(&gsm->t2_timer);
2116 /* Now we are sure T2 has stopped */
2118 gsm_dlci_begin_close(dlci);
2119 wait_event_interruptible(gsm->event,
2120 dlci->state == DLCI_CLOSED);
2122 if (signal_pending(current))
2129 * gsm_cleanup_mux - generic GSM protocol cleanup
2132 * Clean up the bits of the mux which are the same for all framing
2133 * protocols. Remove the mux from the mux table, stop all the timers
2134 * and then shut down each device hanging up the channels as we go.
2137 static void gsm_cleanup_mux(struct gsm_mux *gsm)
2140 struct gsm_dlci *dlci = gsm->dlci[0];
2141 struct gsm_msg *txq, *ntxq;
2145 spin_lock(&gsm_mux_lock);
2146 for (i = 0; i < MAX_MUX; i++) {
2147 if (gsm_mux[i] == gsm) {
2152 spin_unlock(&gsm_mux_lock);
2153 /* open failed before registering => nothing to do */
2157 del_timer_sync(&gsm->t2_timer);
2158 /* Now we are sure T2 has stopped */
2162 /* Free up any link layer users */
2163 mutex_lock(&gsm->mutex);
2164 for (i = 0; i < NUM_DLCI; i++)
2166 gsm_dlci_release(gsm->dlci[i]);
2167 mutex_unlock(&gsm->mutex);
2168 /* Now wipe the queues */
2169 list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list)
2171 INIT_LIST_HEAD(&gsm->tx_list);
2175 * gsm_activate_mux - generic GSM setup
2178 * Set up the bits of the mux which are the same for all framing
2179 * protocols. Add the mux to the mux table so it can be opened and
2180 * finally kick off connecting to DLCI 0 on the modem.
2183 static int gsm_activate_mux(struct gsm_mux *gsm)
2185 struct gsm_dlci *dlci;
2188 timer_setup(&gsm->t2_timer, gsm_control_retransmit, 0);
2189 init_waitqueue_head(&gsm->event);
2190 spin_lock_init(&gsm->control_lock);
2191 spin_lock_init(&gsm->tx_lock);
2193 if (gsm->encoding == 0)
2194 gsm->receive = gsm0_receive;
2196 gsm->receive = gsm1_receive;
2198 spin_lock(&gsm_mux_lock);
2199 for (i = 0; i < MAX_MUX; i++) {
2200 if (gsm_mux[i] == NULL) {
2206 spin_unlock(&gsm_mux_lock);
2210 dlci = gsm_dlci_alloc(gsm, 0);
2213 gsm->dead = false; /* Tty opens are now permissible */
2218 * gsm_free_mux - free up a mux
2221 * Dispose of allocated resources for a dead mux
2223 static void gsm_free_mux(struct gsm_mux *gsm)
2225 kfree(gsm->txframe);
2231 * gsm_free_muxr - free up a mux
2232 * @ref: kreference to the mux to free
2234 * Dispose of allocated resources for a dead mux
2236 static void gsm_free_muxr(struct kref *ref)
2238 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref);
2242 static inline void mux_get(struct gsm_mux *gsm)
2244 kref_get(&gsm->ref);
2247 static inline void mux_put(struct gsm_mux *gsm)
2249 kref_put(&gsm->ref, gsm_free_muxr);
2252 static inline unsigned int mux_num_to_base(struct gsm_mux *gsm)
2254 return gsm->num * NUM_DLCI;
2257 static inline unsigned int mux_line_to_num(unsigned int line)
2259 return line / NUM_DLCI;
2263 * gsm_alloc_mux - allocate a mux
2265 * Creates a new mux ready for activation.
2268 static struct gsm_mux *gsm_alloc_mux(void)
2270 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
2273 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL);
2274 if (gsm->buf == NULL) {
2278 gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL);
2279 if (gsm->txframe == NULL) {
2284 spin_lock_init(&gsm->lock);
2285 mutex_init(&gsm->mutex);
2286 kref_init(&gsm->ref);
2287 INIT_LIST_HEAD(&gsm->tx_list);
2295 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
2297 gsm->dead = true; /* Avoid early tty opens */
2302 static void gsm_copy_config_values(struct gsm_mux *gsm,
2303 struct gsm_config *c)
2305 memset(c, 0, sizeof(*c));
2306 c->adaption = gsm->adaption;
2307 c->encapsulation = gsm->encoding;
2308 c->initiator = gsm->initiator;
2311 c->t3 = 0; /* Not supported */
2313 if (gsm->ftype == UIH)
2317 pr_debug("Ftype %d i %d\n", gsm->ftype, c->i);
2323 static int gsm_config(struct gsm_mux *gsm, struct gsm_config *c)
2326 int need_restart = 0;
2328 /* Stuff we don't support yet - UI or I frame transport, windowing */
2329 if ((c->adaption != 1 && c->adaption != 2) || c->k)
2331 /* Check the MRU/MTU range looks sane */
2332 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8)
2336 if (c->encapsulation > 1) /* Basic, advanced, no I */
2338 if (c->initiator > 1)
2340 if (c->i == 0 || c->i > 2) /* UIH and UI only */
2343 * See what is needed for reconfiguration
2347 if (c->t1 != 0 && c->t1 != gsm->t1)
2349 if (c->t2 != 0 && c->t2 != gsm->t2)
2351 if (c->encapsulation != gsm->encoding)
2353 if (c->adaption != gsm->adaption)
2356 if (c->initiator != gsm->initiator)
2358 if (c->mru != gsm->mru)
2360 if (c->mtu != gsm->mtu)
2364 * Close down what is needed, restart and initiate the new
2368 if (gsm->initiator && (need_close || need_restart)) {
2371 ret = gsm_disconnect(gsm);
2377 gsm_cleanup_mux(gsm);
2379 gsm->initiator = c->initiator;
2382 gsm->encoding = c->encapsulation;
2383 gsm->adaption = c->adaption;
2397 * FIXME: We need to separate activation/deactivation from adding
2398 * and removing from the mux array
2401 gsm_activate_mux(gsm);
2402 if (gsm->initiator && need_close)
2403 gsm_dlci_begin_open(gsm->dlci[0]);
2408 * gsmld_output - write to link
2410 * @data: bytes to output
2413 * Write a block of data from the GSM mux to the data channel. This
2414 * will eventually be serialized from above but at the moment isn't.
2417 static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
2419 if (tty_write_room(gsm->tty) < len) {
2420 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
2424 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET,
2426 return gsm->tty->ops->write(gsm->tty, data, len);
2430 * gsmld_attach_gsm - mode set up
2431 * @tty: our tty structure
2434 * Set up the MUX for basic mode and commence connecting to the
2435 * modem. Currently called from the line discipline set up but
2436 * will need moving to an ioctl path.
2439 static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2444 gsm->tty = tty_kref_get(tty);
2445 ret = gsm_activate_mux(gsm);
2447 tty_kref_put(gsm->tty);
2449 /* Don't register device 0 - this is the control channel and not
2450 a usable tty interface */
2451 if (gsm->initiator) {
2452 base = mux_num_to_base(gsm); /* Base for this MUX */
2453 for (i = 1; i < NUM_DLCI; i++) {
2456 dev = tty_register_device(gsm_tty_driver,
2459 for (i--; i >= 1; i--)
2460 tty_unregister_device(gsm_tty_driver,
2462 return PTR_ERR(dev);
2472 * gsmld_detach_gsm - stop doing 0710 mux
2473 * @tty: tty attached to the mux
2476 * Shutdown and then clean up the resources used by the line discipline
2479 static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2481 unsigned int base = mux_num_to_base(gsm); /* Base for this MUX */
2484 WARN_ON(tty != gsm->tty);
2485 if (gsm->initiator) {
2486 for (i = 1; i < NUM_DLCI; i++)
2487 tty_unregister_device(gsm_tty_driver, base + i);
2489 gsm_cleanup_mux(gsm);
2490 tty_kref_put(gsm->tty);
2494 static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
2495 const char *fp, int count)
2497 struct gsm_mux *gsm = tty->disc_data;
2498 char flags = TTY_NORMAL;
2501 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET,
2504 for (; count; count--, cp++) {
2509 gsm->receive(gsm, *cp);
2518 WARN_ONCE(1, "%s: unknown flag %d\n",
2519 tty_name(tty), flags);
2523 /* FASYNC if needed ? */
2524 /* If clogged call tty_throttle(tty); */
2528 * gsmld_flush_buffer - clean input queue
2529 * @tty: terminal device
2531 * Flush the input buffer. Called when the line discipline is
2532 * being closed, when the tty layer wants the buffer flushed (eg
2536 static void gsmld_flush_buffer(struct tty_struct *tty)
2541 * gsmld_close - close the ldisc for this tty
2544 * Called from the terminal layer when this line discipline is
2545 * being shut down, either because of a close or becsuse of a
2546 * discipline change. The function will not be called while other
2547 * ldisc methods are in progress.
2550 static void gsmld_close(struct tty_struct *tty)
2552 struct gsm_mux *gsm = tty->disc_data;
2554 gsmld_detach_gsm(tty, gsm);
2556 gsmld_flush_buffer(tty);
2557 /* Do other clean up here */
2562 * gsmld_open - open an ldisc
2563 * @tty: terminal to open
2565 * Called when this line discipline is being attached to the
2566 * terminal device. Can sleep. Called serialized so that no
2567 * other events will occur in parallel. No further open will occur
2571 static int gsmld_open(struct tty_struct *tty)
2573 struct gsm_mux *gsm;
2576 if (tty->ops->write == NULL)
2579 /* Attach our ldisc data */
2580 gsm = gsm_alloc_mux();
2584 tty->disc_data = gsm;
2585 tty->receive_room = 65536;
2587 /* Attach the initial passive connection */
2590 ret = gsmld_attach_gsm(tty, gsm);
2592 gsm_cleanup_mux(gsm);
2599 * gsmld_write_wakeup - asynchronous I/O notifier
2602 * Required for the ptys, serial driver etc. since processes
2603 * that attach themselves to the master and rely on ASYNC
2604 * IO must be woken up
2607 static void gsmld_write_wakeup(struct tty_struct *tty)
2609 struct gsm_mux *gsm = tty->disc_data;
2610 unsigned long flags;
2613 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2614 spin_lock_irqsave(&gsm->tx_lock, flags);
2615 gsm_data_kick(gsm, NULL);
2616 if (gsm->tx_bytes < TX_THRESH_LO) {
2617 gsm_dlci_data_sweep(gsm);
2619 spin_unlock_irqrestore(&gsm->tx_lock, flags);
2623 * gsmld_read - read function for tty
2625 * @file: file object
2626 * @buf: userspace buffer pointer
2631 * Perform reads for the line discipline. We are guaranteed that the
2632 * line discipline will not be closed under us but we may get multiple
2633 * parallel readers and must handle this ourselves. We may also get
2634 * a hangup. Always called in user context, may sleep.
2636 * This code must be sure never to sleep through a hangup.
2639 static ssize_t gsmld_read(struct tty_struct *tty, struct file *file,
2640 unsigned char *buf, size_t nr,
2641 void **cookie, unsigned long offset)
2647 * gsmld_write - write function for tty
2649 * @file: file object
2650 * @buf: userspace buffer pointer
2653 * Called when the owner of the device wants to send a frame
2654 * itself (or some other control data). The data is transferred
2655 * as-is and must be properly framed and checksummed as appropriate
2656 * by userspace. Frames are either sent whole or not at all as this
2657 * avoids pain user side.
2660 static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
2661 const unsigned char *buf, size_t nr)
2663 int space = tty_write_room(tty);
2665 return tty->ops->write(tty, buf, nr);
2666 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2671 * gsmld_poll - poll method for N_GSM0710
2672 * @tty: terminal device
2673 * @file: file accessing it
2676 * Called when the line discipline is asked to poll() for data or
2677 * for special events. This code is not serialized with respect to
2678 * other events save open/close.
2680 * This code must be sure never to sleep through a hangup.
2681 * Called without the kernel lock held - fine
2684 static __poll_t gsmld_poll(struct tty_struct *tty, struct file *file,
2688 struct gsm_mux *gsm = tty->disc_data;
2690 poll_wait(file, &tty->read_wait, wait);
2691 poll_wait(file, &tty->write_wait, wait);
2692 if (tty_hung_up_p(file))
2694 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
2695 mask |= EPOLLOUT | EPOLLWRNORM;
2701 static int gsmld_ioctl(struct tty_struct *tty, unsigned int cmd,
2704 struct gsm_config c;
2705 struct gsm_mux *gsm = tty->disc_data;
2709 case GSMIOC_GETCONF:
2710 gsm_copy_config_values(gsm, &c);
2711 if (copy_to_user((void __user *)arg, &c, sizeof(c)))
2714 case GSMIOC_SETCONF:
2715 if (copy_from_user(&c, (void __user *)arg, sizeof(c)))
2717 return gsm_config(gsm, &c);
2718 case GSMIOC_GETFIRST:
2719 base = mux_num_to_base(gsm);
2720 return put_user(base + 1, (__u32 __user *)arg);
2722 return n_tty_ioctl_helper(tty, cmd, arg);
2731 static int gsm_mux_net_open(struct net_device *net)
2733 pr_debug("%s called\n", __func__);
2734 netif_start_queue(net);
2738 static int gsm_mux_net_close(struct net_device *net)
2740 netif_stop_queue(net);
2744 static void dlci_net_free(struct gsm_dlci *dlci)
2750 dlci->adaption = dlci->prev_adaption;
2751 dlci->data = dlci->prev_data;
2752 free_netdev(dlci->net);
2755 static void net_free(struct kref *ref)
2757 struct gsm_mux_net *mux_net;
2758 struct gsm_dlci *dlci;
2760 mux_net = container_of(ref, struct gsm_mux_net, ref);
2761 dlci = mux_net->dlci;
2764 unregister_netdev(dlci->net);
2765 dlci_net_free(dlci);
2769 static inline void muxnet_get(struct gsm_mux_net *mux_net)
2771 kref_get(&mux_net->ref);
2774 static inline void muxnet_put(struct gsm_mux_net *mux_net)
2776 kref_put(&mux_net->ref, net_free);
2779 static netdev_tx_t gsm_mux_net_start_xmit(struct sk_buff *skb,
2780 struct net_device *net)
2782 struct gsm_mux_net *mux_net = netdev_priv(net);
2783 struct gsm_dlci *dlci = mux_net->dlci;
2784 muxnet_get(mux_net);
2786 skb_queue_head(&dlci->skb_list, skb);
2787 net->stats.tx_packets++;
2788 net->stats.tx_bytes += skb->len;
2789 gsm_dlci_data_kick(dlci);
2790 /* And tell the kernel when the last transmit started. */
2791 netif_trans_update(net);
2792 muxnet_put(mux_net);
2793 return NETDEV_TX_OK;
2796 /* called when a packet did not ack after watchdogtimeout */
2797 static void gsm_mux_net_tx_timeout(struct net_device *net, unsigned int txqueue)
2799 /* Tell syslog we are hosed. */
2800 dev_dbg(&net->dev, "Tx timed out.\n");
2802 /* Update statistics */
2803 net->stats.tx_errors++;
2806 static void gsm_mux_rx_netchar(struct gsm_dlci *dlci,
2807 const unsigned char *in_buf, int size)
2809 struct net_device *net = dlci->net;
2810 struct sk_buff *skb;
2811 struct gsm_mux_net *mux_net = netdev_priv(net);
2812 muxnet_get(mux_net);
2814 /* Allocate an sk_buff */
2815 skb = dev_alloc_skb(size + NET_IP_ALIGN);
2817 /* We got no receive buffer. */
2818 net->stats.rx_dropped++;
2819 muxnet_put(mux_net);
2822 skb_reserve(skb, NET_IP_ALIGN);
2823 skb_put_data(skb, in_buf, size);
2826 skb->protocol = htons(ETH_P_IP);
2828 /* Ship it off to the kernel */
2831 /* update out statistics */
2832 net->stats.rx_packets++;
2833 net->stats.rx_bytes += size;
2834 muxnet_put(mux_net);
2838 static void gsm_mux_net_init(struct net_device *net)
2840 static const struct net_device_ops gsm_netdev_ops = {
2841 .ndo_open = gsm_mux_net_open,
2842 .ndo_stop = gsm_mux_net_close,
2843 .ndo_start_xmit = gsm_mux_net_start_xmit,
2844 .ndo_tx_timeout = gsm_mux_net_tx_timeout,
2847 net->netdev_ops = &gsm_netdev_ops;
2849 /* fill in the other fields */
2850 net->watchdog_timeo = GSM_NET_TX_TIMEOUT;
2851 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
2852 net->type = ARPHRD_NONE;
2853 net->tx_queue_len = 10;
2857 /* caller holds the dlci mutex */
2858 static void gsm_destroy_network(struct gsm_dlci *dlci)
2860 struct gsm_mux_net *mux_net;
2862 pr_debug("destroy network interface\n");
2865 mux_net = netdev_priv(dlci->net);
2866 muxnet_put(mux_net);
2870 /* caller holds the dlci mutex */
2871 static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
2875 struct net_device *net;
2876 struct gsm_mux_net *mux_net;
2878 if (!capable(CAP_NET_ADMIN))
2881 /* Already in a non tty mode */
2882 if (dlci->adaption > 2)
2885 if (nc->protocol != htons(ETH_P_IP))
2886 return -EPROTONOSUPPORT;
2888 if (nc->adaption != 3 && nc->adaption != 4)
2889 return -EPROTONOSUPPORT;
2891 pr_debug("create network interface\n");
2894 if (nc->if_name[0] != '\0')
2895 netname = nc->if_name;
2896 net = alloc_netdev(sizeof(struct gsm_mux_net), netname,
2897 NET_NAME_UNKNOWN, gsm_mux_net_init);
2899 pr_err("alloc_netdev failed\n");
2902 net->mtu = dlci->gsm->mtu;
2904 net->max_mtu = dlci->gsm->mtu;
2905 mux_net = netdev_priv(net);
2906 mux_net->dlci = dlci;
2907 kref_init(&mux_net->ref);
2908 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */
2910 /* reconfigure dlci for network */
2911 dlci->prev_adaption = dlci->adaption;
2912 dlci->prev_data = dlci->data;
2913 dlci->adaption = nc->adaption;
2914 dlci->data = gsm_mux_rx_netchar;
2917 pr_debug("register netdev\n");
2918 retval = register_netdev(net);
2920 pr_err("network register fail %d\n", retval);
2921 dlci_net_free(dlci);
2924 return net->ifindex; /* return network index */
2927 /* Line discipline for real tty */
2928 static struct tty_ldisc_ops tty_ldisc_packet = {
2929 .owner = THIS_MODULE,
2933 .close = gsmld_close,
2934 .flush_buffer = gsmld_flush_buffer,
2936 .write = gsmld_write,
2937 .ioctl = gsmld_ioctl,
2939 .receive_buf = gsmld_receive_buf,
2940 .write_wakeup = gsmld_write_wakeup
2949 static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk)
2952 struct gsm_control *ctrl;
2958 modembits[0] = len << 1 | EA; /* Data bytes */
2959 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */
2960 modembits[2] = gsm_encode_modem(dlci) << 1 | EA;
2962 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */
2963 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1);
2966 return gsm_control_wait(dlci->gsm, ctrl);
2969 static int gsm_carrier_raised(struct tty_port *port)
2971 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2972 struct gsm_mux *gsm = dlci->gsm;
2974 /* Not yet open so no carrier info */
2975 if (dlci->state != DLCI_OPEN)
2981 * Basic mode with control channel in ADM mode may not respond
2982 * to CMD_MSC at all and modem_rx is empty.
2984 if (gsm->encoding == 0 && gsm->dlci[0]->mode == DLCI_MODE_ADM &&
2988 return dlci->modem_rx & TIOCM_CD;
2991 static void gsm_dtr_rts(struct tty_port *port, int onoff)
2993 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2994 unsigned int modem_tx = dlci->modem_tx;
2996 modem_tx |= TIOCM_DTR | TIOCM_RTS;
2998 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
2999 if (modem_tx != dlci->modem_tx) {
3000 dlci->modem_tx = modem_tx;
3001 gsmtty_modem_update(dlci, 0);
3005 static const struct tty_port_operations gsm_port_ops = {
3006 .carrier_raised = gsm_carrier_raised,
3007 .dtr_rts = gsm_dtr_rts,
3008 .destruct = gsm_dlci_free,
3011 static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty)
3013 struct gsm_mux *gsm;
3014 struct gsm_dlci *dlci;
3015 unsigned int line = tty->index;
3016 unsigned int mux = mux_line_to_num(line);
3024 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
3025 if (gsm_mux[mux] == NULL)
3027 if (line == 0 || line > 61) /* 62/63 reserved */
3032 /* If DLCI 0 is not yet fully open return an error.
3033 This is ok from a locking
3034 perspective as we don't have to worry about this
3036 mutex_lock(&gsm->mutex);
3037 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN) {
3038 mutex_unlock(&gsm->mutex);
3041 dlci = gsm->dlci[line];
3044 dlci = gsm_dlci_alloc(gsm, line);
3047 mutex_unlock(&gsm->mutex);
3050 ret = tty_port_install(&dlci->port, driver, tty);
3054 mutex_unlock(&gsm->mutex);
3059 dlci_get(gsm->dlci[0]);
3061 tty->driver_data = dlci;
3062 mutex_unlock(&gsm->mutex);
3067 static int gsmtty_open(struct tty_struct *tty, struct file *filp)
3069 struct gsm_dlci *dlci = tty->driver_data;
3070 struct tty_port *port = &dlci->port;
3071 struct gsm_mux *gsm = dlci->gsm;
3074 tty_port_tty_set(port, tty);
3077 /* We could in theory open and close before we wait - eg if we get
3078 a DM straight back. This is ok as that will have caused a hangup */
3079 tty_port_set_initialized(port, 1);
3080 /* Start sending off SABM messages */
3082 gsm_dlci_begin_open(dlci);
3083 /* And wait for virtual carrier */
3084 return tty_port_block_til_ready(port, tty, filp);
3087 static void gsmtty_close(struct tty_struct *tty, struct file *filp)
3089 struct gsm_dlci *dlci = tty->driver_data;
3093 if (dlci->state == DLCI_CLOSED)
3095 mutex_lock(&dlci->mutex);
3096 gsm_destroy_network(dlci);
3097 mutex_unlock(&dlci->mutex);
3098 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
3100 gsm_dlci_begin_close(dlci);
3101 if (tty_port_initialized(&dlci->port) && C_HUPCL(tty))
3102 tty_port_lower_dtr_rts(&dlci->port);
3103 tty_port_close_end(&dlci->port, tty);
3104 tty_port_tty_set(&dlci->port, NULL);
3108 static void gsmtty_hangup(struct tty_struct *tty)
3110 struct gsm_dlci *dlci = tty->driver_data;
3111 if (dlci->state == DLCI_CLOSED)
3113 tty_port_hangup(&dlci->port);
3114 gsm_dlci_begin_close(dlci);
3117 static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf,
3121 struct gsm_dlci *dlci = tty->driver_data;
3122 if (dlci->state == DLCI_CLOSED)
3124 /* Stuff the bytes into the fifo queue */
3125 sent = kfifo_in_locked(&dlci->fifo, buf, len, &dlci->lock);
3126 /* Need to kick the channel */
3127 gsm_dlci_data_kick(dlci);
3131 static unsigned int gsmtty_write_room(struct tty_struct *tty)
3133 struct gsm_dlci *dlci = tty->driver_data;
3134 if (dlci->state == DLCI_CLOSED)
3136 return TX_SIZE - kfifo_len(&dlci->fifo);
3139 static unsigned int gsmtty_chars_in_buffer(struct tty_struct *tty)
3141 struct gsm_dlci *dlci = tty->driver_data;
3142 if (dlci->state == DLCI_CLOSED)
3144 return kfifo_len(&dlci->fifo);
3147 static void gsmtty_flush_buffer(struct tty_struct *tty)
3149 struct gsm_dlci *dlci = tty->driver_data;
3150 if (dlci->state == DLCI_CLOSED)
3152 /* Caution needed: If we implement reliable transport classes
3153 then the data being transmitted can't simply be junked once
3154 it has first hit the stack. Until then we can just blow it
3156 kfifo_reset(&dlci->fifo);
3157 /* Need to unhook this DLCI from the transmit queue logic */
3160 static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
3162 /* The FIFO handles the queue so the kernel will do the right
3163 thing waiting on chars_in_buffer before calling us. No work
3167 static int gsmtty_tiocmget(struct tty_struct *tty)
3169 struct gsm_dlci *dlci = tty->driver_data;
3170 if (dlci->state == DLCI_CLOSED)
3172 return dlci->modem_rx;
3175 static int gsmtty_tiocmset(struct tty_struct *tty,
3176 unsigned int set, unsigned int clear)
3178 struct gsm_dlci *dlci = tty->driver_data;
3179 unsigned int modem_tx = dlci->modem_tx;
3181 if (dlci->state == DLCI_CLOSED)
3186 if (modem_tx != dlci->modem_tx) {
3187 dlci->modem_tx = modem_tx;
3188 return gsmtty_modem_update(dlci, 0);
3194 static int gsmtty_ioctl(struct tty_struct *tty,
3195 unsigned int cmd, unsigned long arg)
3197 struct gsm_dlci *dlci = tty->driver_data;
3198 struct gsm_netconfig nc;
3201 if (dlci->state == DLCI_CLOSED)
3204 case GSMIOC_ENABLE_NET:
3205 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc)))
3207 nc.if_name[IFNAMSIZ-1] = '\0';
3208 /* return net interface index or error code */
3209 mutex_lock(&dlci->mutex);
3210 index = gsm_create_network(dlci, &nc);
3211 mutex_unlock(&dlci->mutex);
3212 if (copy_to_user((void __user *)arg, &nc, sizeof(nc)))
3215 case GSMIOC_DISABLE_NET:
3216 if (!capable(CAP_NET_ADMIN))
3218 mutex_lock(&dlci->mutex);
3219 gsm_destroy_network(dlci);
3220 mutex_unlock(&dlci->mutex);
3223 return -ENOIOCTLCMD;
3227 static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old)
3229 struct gsm_dlci *dlci = tty->driver_data;
3230 if (dlci->state == DLCI_CLOSED)
3232 /* For the moment its fixed. In actual fact the speed information
3233 for the virtual channel can be propogated in both directions by
3234 the RPN control message. This however rapidly gets nasty as we
3235 then have to remap modem signals each way according to whether
3236 our virtual cable is null modem etc .. */
3237 tty_termios_copy_hw(&tty->termios, old);
3240 static void gsmtty_throttle(struct tty_struct *tty)
3242 struct gsm_dlci *dlci = tty->driver_data;
3243 if (dlci->state == DLCI_CLOSED)
3246 dlci->modem_tx &= ~TIOCM_DTR;
3247 dlci->throttled = true;
3248 /* Send an MSC with DTR cleared */
3249 gsmtty_modem_update(dlci, 0);
3252 static void gsmtty_unthrottle(struct tty_struct *tty)
3254 struct gsm_dlci *dlci = tty->driver_data;
3255 if (dlci->state == DLCI_CLOSED)
3258 dlci->modem_tx |= TIOCM_DTR;
3259 dlci->throttled = false;
3260 /* Send an MSC with DTR set */
3261 gsmtty_modem_update(dlci, 0);
3264 static int gsmtty_break_ctl(struct tty_struct *tty, int state)
3266 struct gsm_dlci *dlci = tty->driver_data;
3267 int encode = 0; /* Off */
3268 if (dlci->state == DLCI_CLOSED)
3271 if (state == -1) /* "On indefinitely" - we can't encode this
3274 else if (state > 0) {
3275 encode = state / 200; /* mS to encoding */
3277 encode = 0x0F; /* Best effort */
3279 return gsmtty_modem_update(dlci, encode);
3282 static void gsmtty_cleanup(struct tty_struct *tty)
3284 struct gsm_dlci *dlci = tty->driver_data;
3285 struct gsm_mux *gsm = dlci->gsm;
3288 dlci_put(gsm->dlci[0]);
3292 /* Virtual ttys for the demux */
3293 static const struct tty_operations gsmtty_ops = {
3294 .install = gsmtty_install,
3295 .open = gsmtty_open,
3296 .close = gsmtty_close,
3297 .write = gsmtty_write,
3298 .write_room = gsmtty_write_room,
3299 .chars_in_buffer = gsmtty_chars_in_buffer,
3300 .flush_buffer = gsmtty_flush_buffer,
3301 .ioctl = gsmtty_ioctl,
3302 .throttle = gsmtty_throttle,
3303 .unthrottle = gsmtty_unthrottle,
3304 .set_termios = gsmtty_set_termios,
3305 .hangup = gsmtty_hangup,
3306 .wait_until_sent = gsmtty_wait_until_sent,
3307 .tiocmget = gsmtty_tiocmget,
3308 .tiocmset = gsmtty_tiocmset,
3309 .break_ctl = gsmtty_break_ctl,
3310 .cleanup = gsmtty_cleanup,
3315 static int __init gsm_init(void)
3317 /* Fill in our line protocol discipline, and register it */
3318 int status = tty_register_ldisc(&tty_ldisc_packet);
3320 pr_err("n_gsm: can't register line discipline (err = %d)\n",
3325 gsm_tty_driver = tty_alloc_driver(256, TTY_DRIVER_REAL_RAW |
3326 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_HARDWARE_BREAK);
3327 if (IS_ERR(gsm_tty_driver)) {
3328 pr_err("gsm_init: tty allocation failed.\n");
3329 status = PTR_ERR(gsm_tty_driver);
3330 goto err_unreg_ldisc;
3332 gsm_tty_driver->driver_name = "gsmtty";
3333 gsm_tty_driver->name = "gsmtty";
3334 gsm_tty_driver->major = 0; /* Dynamic */
3335 gsm_tty_driver->minor_start = 0;
3336 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
3337 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
3338 gsm_tty_driver->init_termios = tty_std_termios;
3340 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
3341 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
3343 if (tty_register_driver(gsm_tty_driver)) {
3344 pr_err("gsm_init: tty registration failed.\n");
3346 goto err_put_driver;
3348 pr_debug("gsm_init: loaded as %d,%d.\n",
3349 gsm_tty_driver->major, gsm_tty_driver->minor_start);
3352 tty_driver_kref_put(gsm_tty_driver);
3354 tty_unregister_ldisc(&tty_ldisc_packet);
3358 static void __exit gsm_exit(void)
3360 tty_unregister_ldisc(&tty_ldisc_packet);
3361 tty_unregister_driver(gsm_tty_driver);
3362 tty_driver_kref_put(gsm_tty_driver);
3365 module_init(gsm_init);
3366 module_exit(gsm_exit);
3369 MODULE_LICENSE("GPL");
3370 MODULE_ALIAS_LDISC(N_GSM0710);