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;
275 * This section of the driver logic implements the GSM encodings
276 * both the basic and the 'advanced'. Reliable transport is not
284 /* I is special: the rest are ..*/
295 /* Channel commands */
297 #define CMD_TEST 0x11
300 #define CMD_FCOFF 0x31
303 #define CMD_FCON 0x51
308 /* Virtual modem bits */
315 #define GSM0_SOF 0xF9
316 #define GSM1_SOF 0x7E
317 #define GSM1_ESCAPE 0x7D
318 #define GSM1_ESCAPE_BITS 0x20
322 static const struct tty_port_operations gsm_port_ops;
325 * CRC table for GSM 0710
328 static const u8 gsm_fcs8[256] = {
329 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75,
330 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B,
331 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69,
332 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67,
333 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D,
334 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43,
335 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51,
336 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F,
337 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05,
338 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B,
339 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19,
340 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17,
341 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D,
342 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33,
343 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21,
344 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F,
345 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95,
346 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B,
347 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89,
348 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87,
349 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD,
350 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3,
351 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1,
352 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF,
353 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5,
354 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB,
355 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9,
356 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7,
357 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD,
358 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3,
359 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1,
360 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF
363 #define INIT_FCS 0xFF
364 #define GOOD_FCS 0xCF
366 static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len);
369 * gsm_fcs_add - update FCS
373 * Update the FCS to include c. Uses the algorithm in the specification
377 static inline u8 gsm_fcs_add(u8 fcs, u8 c)
379 return gsm_fcs8[fcs ^ c];
383 * gsm_fcs_add_block - update FCS for a block
386 * @len: length of buffer
388 * Update the FCS to include c. Uses the algorithm in the specification
392 static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len)
395 fcs = gsm_fcs8[fcs ^ *c++];
400 * gsm_read_ea - read a byte into an EA
401 * @val: variable holding value
402 * @c: byte going into the EA
404 * Processes one byte of an EA. Updates the passed variable
405 * and returns 1 if the EA is now completely read
408 static int gsm_read_ea(unsigned int *val, u8 c)
410 /* Add the next 7 bits into the value */
413 /* Was this the last byte of the EA 1 = yes*/
418 * gsm_encode_modem - encode modem data bits
419 * @dlci: DLCI to encode from
421 * Returns the correct GSM encoded modem status bits (6 bit field) for
422 * the current status of the DLCI and attached tty object
425 static u8 gsm_encode_modem(const struct gsm_dlci *dlci)
428 /* FC is true flow control not modem bits */
431 if (dlci->modem_tx & TIOCM_DTR)
432 modembits |= MDM_RTC;
433 if (dlci->modem_tx & TIOCM_RTS)
434 modembits |= MDM_RTR;
435 if (dlci->modem_tx & TIOCM_RI)
437 if (dlci->modem_tx & TIOCM_CD)
443 * gsm_print_packet - display a frame for debug
444 * @hdr: header to print before decode
445 * @addr: address EA from the frame
446 * @cr: C/R bit from the frame
447 * @control: control including PF bit
448 * @data: following data bytes
449 * @dlen: length of data
451 * Displays a packet in human readable format for debugging purposes. The
452 * style is based on amateur radio LAP-B dump display.
455 static void gsm_print_packet(const char *hdr, int addr, int cr,
456 u8 control, const u8 *data, int dlen)
461 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]);
463 switch (control & ~PF) {
483 if (!(control & 0x01)) {
484 pr_cont("I N(S)%d N(R)%d",
485 (control & 0x0E) >> 1, (control & 0xE0) >> 5);
486 } else switch (control & 0x0F) {
488 pr_cont("RR(%d)", (control & 0xE0) >> 5);
491 pr_cont("RNR(%d)", (control & 0xE0) >> 5);
494 pr_cont("REJ(%d)", (control & 0xE0) >> 5);
497 pr_cont("[%02X]", control);
506 print_hex_dump_bytes("", DUMP_PREFIX_NONE, data, dlen);
511 * Link level transmission side
515 * gsm_stuff_frame - bytestuff a packet
516 * @input: input buffer
517 * @output: output buffer
518 * @len: length of input
520 * Expand a buffer by bytestuffing it. The worst case size change
521 * is doubling and the caller is responsible for handing out
522 * suitable sized buffers.
525 static int gsm_stuff_frame(const u8 *input, u8 *output, int len)
529 if (*input == GSM1_SOF || *input == GSM1_ESCAPE
530 || *input == XON || *input == XOFF) {
531 *output++ = GSM1_ESCAPE;
532 *output++ = *input++ ^ GSM1_ESCAPE_BITS;
535 *output++ = *input++;
542 * gsm_send - send a control frame
544 * @addr: address for control frame
545 * @cr: command/response bit
546 * @control: control byte including PF bit
548 * Format up and transmit a control frame. These do not go via the
549 * queueing logic as they should be transmitted ahead of data when
552 * FIXME: Lock versus data TX path
555 static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control)
561 switch (gsm->encoding) {
564 cbuf[1] = (addr << 2) | (cr << 1) | EA;
566 cbuf[3] = EA; /* Length of data = 0 */
567 cbuf[4] = 0xFF - gsm_fcs_add_block(INIT_FCS, cbuf + 1, 3);
573 /* Control frame + packing (but not frame stuffing) in mode 1 */
574 ibuf[0] = (addr << 2) | (cr << 1) | EA;
576 ibuf[2] = 0xFF - gsm_fcs_add_block(INIT_FCS, ibuf, 2);
577 /* Stuffing may double the size worst case */
578 len = gsm_stuff_frame(ibuf, cbuf + 1, 3);
579 /* Now add the SOF markers */
581 cbuf[len + 1] = GSM1_SOF;
582 /* FIXME: we can omit the lead one in many cases */
589 gsmld_output(gsm, cbuf, len);
590 gsm_print_packet("-->", addr, cr, control, NULL, 0);
594 * gsm_response - send a control response
596 * @addr: address for control frame
597 * @control: control byte including PF bit
599 * Format up and transmit a link level response frame.
602 static inline void gsm_response(struct gsm_mux *gsm, int addr, int control)
604 gsm_send(gsm, addr, 0, control);
608 * gsm_command - send a control command
610 * @addr: address for control frame
611 * @control: control byte including PF bit
613 * Format up and transmit a link level command frame.
616 static inline void gsm_command(struct gsm_mux *gsm, int addr, int control)
618 gsm_send(gsm, addr, 1, control);
621 /* Data transmission */
623 #define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */
626 * gsm_data_alloc - allocate data frame
628 * @addr: DLCI address
629 * @len: length excluding header and FCS
630 * @ctrl: control byte
632 * Allocate a new data buffer for sending frames with data. Space is left
633 * at the front for header bytes but that is treated as an implementation
634 * detail and not for the high level code to use
637 static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
640 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN,
644 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */
648 INIT_LIST_HEAD(&m->list);
653 * gsm_data_kick - poke the queue
655 * @dlci: DLCI sending the data
657 * The tty device has called us to indicate that room has appeared in
658 * the transmit queue. Ram more data into the pipe if we have any
659 * If we have been flow-stopped by a CMD_FCOFF, then we can only
660 * send messages on DLCI0 until CMD_FCON
662 * FIXME: lock against link layer control transmissions
665 static void gsm_data_kick(struct gsm_mux *gsm, struct gsm_dlci *dlci)
667 struct gsm_msg *msg, *nmsg;
670 list_for_each_entry_safe(msg, nmsg, &gsm->tx_list, list) {
671 if (gsm->constipated && msg->addr)
673 if (gsm->encoding != 0) {
674 gsm->txframe[0] = GSM1_SOF;
675 len = gsm_stuff_frame(msg->data,
676 gsm->txframe + 1, msg->len);
677 gsm->txframe[len + 1] = GSM1_SOF;
680 gsm->txframe[0] = GSM0_SOF;
681 memcpy(gsm->txframe + 1 , msg->data, msg->len);
682 gsm->txframe[msg->len + 1] = GSM0_SOF;
687 print_hex_dump_bytes("gsm_data_kick: ",
690 if (gsmld_output(gsm, gsm->txframe, len) < 0)
692 /* FIXME: Can eliminate one SOF in many more cases */
693 gsm->tx_bytes -= msg->len;
695 list_del(&msg->list);
699 tty_port_tty_wakeup(&dlci->port);
703 for (i = 0; i < NUM_DLCI; i++)
705 tty_port_tty_wakeup(&gsm->dlci[i]->port);
711 * __gsm_data_queue - queue a UI or UIH frame
712 * @dlci: DLCI sending the data
713 * @msg: message queued
715 * Add data to the transmit queue and try and get stuff moving
716 * out of the mux tty if not already doing so. The Caller must hold
720 static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
722 struct gsm_mux *gsm = dlci->gsm;
724 u8 *fcs = dp + msg->len;
726 /* Fill in the header */
727 if (gsm->encoding == 0) {
729 *--dp = (msg->len << 1) | EA;
731 *--dp = (msg->len >> 7); /* bits 7 - 15 */
732 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */
738 *--dp = (msg->addr << 2) | 2 | EA;
740 *--dp = (msg->addr << 2) | EA;
741 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp);
742 /* Ugly protocol layering violation */
743 if (msg->ctrl == UI || msg->ctrl == (UI|PF))
744 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len);
747 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl,
748 msg->data, msg->len);
750 /* Move the header back and adjust the length, also allow for the FCS
751 now tacked on the end */
752 msg->len += (msg->data - dp) + 1;
755 /* Add to the actual output queue */
756 list_add_tail(&msg->list, &gsm->tx_list);
757 gsm->tx_bytes += msg->len;
758 gsm_data_kick(gsm, dlci);
762 * gsm_data_queue - queue a UI or UIH frame
763 * @dlci: DLCI sending the data
764 * @msg: message queued
766 * Add data to the transmit queue and try and get stuff moving
767 * out of the mux tty if not already doing so. Take the
768 * the gsm tx lock and dlci lock.
771 static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
774 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
775 __gsm_data_queue(dlci, msg);
776 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
780 * gsm_dlci_data_output - try and push data out of a DLCI
782 * @dlci: the DLCI to pull data from
784 * Pull data from a DLCI and send it into the transmit queue if there
785 * is data. Keep to the MRU of the mux. This path handles the usual tty
786 * interface which is a byte stream with optional modem data.
788 * Caller must hold the tx_lock of the mux.
791 static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci)
795 int len, total_size, size;
796 int h = dlci->adaption - 1;
800 len = kfifo_len(&dlci->fifo);
804 /* MTU/MRU count only the data bits */
810 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
811 /* FIXME: need a timer or something to kick this so it can't
812 get stuck with no work outstanding and no buffer free */
816 switch (dlci->adaption) {
817 case 1: /* Unstructured */
819 case 2: /* Unstructed with modem bits.
820 Always one byte as we never send inline break data */
821 *dp++ = gsm_encode_modem(dlci);
824 WARN_ON(kfifo_out_locked(&dlci->fifo, dp , len, &dlci->lock) != len);
825 __gsm_data_queue(dlci, msg);
828 /* Bytes of data we used up */
833 * gsm_dlci_data_output_framed - try and push data out of a DLCI
835 * @dlci: the DLCI to pull data from
837 * Pull data from a DLCI and send it into the transmit queue if there
838 * is data. Keep to the MRU of the mux. This path handles framed data
839 * queued as skbuffs to the DLCI.
841 * Caller must hold the tx_lock of the mux.
844 static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
845 struct gsm_dlci *dlci)
850 int last = 0, first = 0;
853 /* One byte per frame is used for B/F flags */
854 if (dlci->adaption == 4)
857 /* dlci->skb is locked by tx_lock */
858 if (dlci->skb == NULL) {
859 dlci->skb = skb_dequeue_tail(&dlci->skb_list);
860 if (dlci->skb == NULL)
864 len = dlci->skb->len + overhead;
866 /* MTU/MRU count only the data bits */
867 if (len > gsm->mtu) {
868 if (dlci->adaption == 3) {
869 /* Over long frame, bin it */
870 dev_kfree_skb_any(dlci->skb);
878 size = len + overhead;
879 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
881 /* FIXME: need a timer or something to kick this so it can't
882 get stuck with no work outstanding and no buffer free */
884 skb_queue_tail(&dlci->skb_list, dlci->skb);
890 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */
891 /* Flag byte to carry the start/end info */
892 *dp++ = last << 7 | first << 6 | 1; /* EA */
895 memcpy(dp, dlci->skb->data, len);
896 skb_pull(dlci->skb, len);
897 __gsm_data_queue(dlci, msg);
899 dev_kfree_skb_any(dlci->skb);
906 * gsm_dlci_data_sweep - look for data to send
909 * Sweep the GSM mux channels in priority order looking for ones with
910 * data to send. We could do with optimising this scan a bit. We aim
911 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit
912 * TX_THRESH_LO we get called again
914 * FIXME: We should round robin between groups and in theory you can
915 * renegotiate DLCI priorities with optional stuff. Needs optimising.
918 static void gsm_dlci_data_sweep(struct gsm_mux *gsm)
921 /* Priority ordering: We should do priority with RR of the groups */
924 while (i < NUM_DLCI) {
925 struct gsm_dlci *dlci;
927 if (gsm->tx_bytes > TX_THRESH_HI)
930 if (dlci == NULL || dlci->constipated) {
934 if (dlci->adaption < 3 && !dlci->net)
935 len = gsm_dlci_data_output(gsm, dlci);
937 len = gsm_dlci_data_output_framed(gsm, dlci);
940 /* DLCI empty - try the next */
947 * gsm_dlci_data_kick - transmit if possible
948 * @dlci: DLCI to kick
950 * Transmit data from this DLCI if the queue is empty. We can't rely on
951 * a tty wakeup except when we filled the pipe so we need to fire off
952 * new data ourselves in other cases.
955 static void gsm_dlci_data_kick(struct gsm_dlci *dlci)
960 if (dlci->constipated)
963 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
964 /* If we have nothing running then we need to fire up */
965 sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO);
966 if (dlci->gsm->tx_bytes == 0) {
968 gsm_dlci_data_output_framed(dlci->gsm, dlci);
970 gsm_dlci_data_output(dlci->gsm, dlci);
973 gsm_dlci_data_sweep(dlci->gsm);
974 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
978 * Control message processing
983 * gsm_control_reply - send a response frame to a control
985 * @cmd: the command to use
986 * @data: data to follow encoded info
987 * @dlen: length of data
989 * Encode up and queue a UI/UIH frame containing our response.
992 static void gsm_control_reply(struct gsm_mux *gsm, int cmd, const u8 *data,
996 msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype);
999 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */
1000 msg->data[1] = (dlen << 1) | EA;
1001 memcpy(msg->data + 2, data, dlen);
1002 gsm_data_queue(gsm->dlci[0], msg);
1006 * gsm_process_modem - process received modem status
1007 * @tty: virtual tty bound to the DLCI
1008 * @dlci: DLCI to affect
1009 * @modem: modem bits (full EA)
1010 * @clen: command length
1012 * Used when a modem control message or line state inline in adaption
1013 * layer 2 is processed. Sort out the local modem state and throttles
1016 static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
1017 u32 modem, int clen)
1023 /* The modem status command can either contain one octet (v.24 signals)
1024 or two octets (v.24 signals + break signals). The length field will
1025 either be 2 or 3 respectively. This is specified in section
1026 5.4.6.3.7 of the 27.010 mux spec. */
1029 modem = modem & 0x7f;
1032 modem = (modem >> 7) & 0x7f;
1035 /* Flow control/ready to communicate */
1036 fc = (modem & MDM_FC) || !(modem & MDM_RTR);
1037 if (fc && !dlci->constipated) {
1038 /* Need to throttle our output on this device */
1039 dlci->constipated = true;
1040 } else if (!fc && dlci->constipated) {
1041 dlci->constipated = false;
1042 gsm_dlci_data_kick(dlci);
1045 /* Map modem bits */
1046 if (modem & MDM_RTC)
1047 mlines |= TIOCM_DSR | TIOCM_DTR;
1048 if (modem & MDM_RTR)
1049 mlines |= TIOCM_RTS | TIOCM_CTS;
1055 /* Carrier drop -> hangup */
1057 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD))
1062 tty_insert_flip_char(&dlci->port, 0, TTY_BREAK);
1063 dlci->modem_rx = mlines;
1067 * gsm_control_modem - modem status received
1069 * @data: data following command
1070 * @clen: command length
1072 * We have received a modem status control message. This is used by
1073 * the GSM mux protocol to pass virtual modem line status and optionally
1074 * to indicate break signals. Unpack it, convert to Linux representation
1075 * and if need be stuff a break message down the tty.
1078 static void gsm_control_modem(struct gsm_mux *gsm, const u8 *data, int clen)
1080 unsigned int addr = 0;
1081 unsigned int modem = 0;
1082 unsigned int brk = 0;
1083 struct gsm_dlci *dlci;
1085 const u8 *dp = data;
1086 struct tty_struct *tty;
1088 while (gsm_read_ea(&addr, *dp++) == 0) {
1093 /* Must be at least one byte following the EA */
1099 /* Closed port, or invalid ? */
1100 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1102 dlci = gsm->dlci[addr];
1104 while (gsm_read_ea(&modem, *dp++) == 0) {
1111 while (gsm_read_ea(&brk, *dp++) == 0) {
1117 modem |= (brk & 0x7f);
1119 tty = tty_port_tty_get(&dlci->port);
1120 gsm_process_modem(tty, dlci, modem, clen);
1125 gsm_control_reply(gsm, CMD_MSC, data, clen);
1129 * gsm_control_rls - remote line status
1132 * @clen: data length
1134 * The modem sends us a two byte message on the control channel whenever
1135 * it wishes to send us an error state from the virtual link. Stuff
1136 * this into the uplink tty if present
1139 static void gsm_control_rls(struct gsm_mux *gsm, const u8 *data, int clen)
1141 struct tty_port *port;
1142 unsigned int addr = 0;
1145 const u8 *dp = data;
1147 while (gsm_read_ea(&addr, *dp++) == 0) {
1152 /* Must be at least one byte following ea */
1157 /* Closed port, or invalid ? */
1158 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1162 if ((bits & 1) == 0)
1165 port = &gsm->dlci[addr]->port;
1168 tty_insert_flip_char(port, 0, TTY_OVERRUN);
1170 tty_insert_flip_char(port, 0, TTY_PARITY);
1172 tty_insert_flip_char(port, 0, TTY_FRAME);
1174 tty_flip_buffer_push(port);
1176 gsm_control_reply(gsm, CMD_RLS, data, clen);
1179 static void gsm_dlci_begin_close(struct gsm_dlci *dlci);
1182 * gsm_control_message - DLCI 0 control processing
1184 * @command: the command EA
1185 * @data: data beyond the command/length EAs
1188 * Input processor for control messages from the other end of the link.
1189 * Processes the incoming request and queues a response frame or an
1190 * NSC response if not supported
1193 static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
1194 const u8 *data, int clen)
1197 unsigned long flags;
1201 struct gsm_dlci *dlci = gsm->dlci[0];
1202 /* Modem wishes to close down */
1206 gsm_dlci_begin_close(dlci);
1211 /* Modem wishes to test, reply with the data */
1212 gsm_control_reply(gsm, CMD_TEST, data, clen);
1215 /* Modem can accept data again */
1216 gsm->constipated = false;
1217 gsm_control_reply(gsm, CMD_FCON, NULL, 0);
1218 /* Kick the link in case it is idling */
1219 spin_lock_irqsave(&gsm->tx_lock, flags);
1220 gsm_data_kick(gsm, NULL);
1221 spin_unlock_irqrestore(&gsm->tx_lock, flags);
1224 /* Modem wants us to STFU */
1225 gsm->constipated = true;
1226 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0);
1229 /* Out of band modem line change indicator for a DLCI */
1230 gsm_control_modem(gsm, data, clen);
1233 /* Out of band error reception for a DLCI */
1234 gsm_control_rls(gsm, data, clen);
1237 /* Modem wishes to enter power saving state */
1238 gsm_control_reply(gsm, CMD_PSC, NULL, 0);
1240 /* Optional unsupported commands */
1241 case CMD_PN: /* Parameter negotiation */
1242 case CMD_RPN: /* Remote port negotiation */
1243 case CMD_SNC: /* Service negotiation command */
1245 /* Reply to bad commands with an NSC */
1247 gsm_control_reply(gsm, CMD_NSC, buf, 1);
1253 * gsm_control_response - process a response to our control
1255 * @command: the command (response) EA
1256 * @data: data beyond the command/length EA
1259 * Process a response to an outstanding command. We only allow a single
1260 * control message in flight so this is fairly easy. All the clean up
1261 * is done by the caller, we just update the fields, flag it as done
1265 static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
1266 const u8 *data, int clen)
1268 struct gsm_control *ctrl;
1269 unsigned long flags;
1271 spin_lock_irqsave(&gsm->control_lock, flags);
1273 ctrl = gsm->pending_cmd;
1274 /* Does the reply match our command */
1276 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) {
1277 /* Our command was replied to, kill the retry timer */
1278 del_timer(&gsm->t2_timer);
1279 gsm->pending_cmd = NULL;
1280 /* Rejected by the other end */
1281 if (command == CMD_NSC)
1282 ctrl->error = -EOPNOTSUPP;
1284 wake_up(&gsm->event);
1286 spin_unlock_irqrestore(&gsm->control_lock, flags);
1290 * gsm_control_transmit - send control packet
1292 * @ctrl: frame to send
1294 * Send out a pending control command (called under control lock)
1297 static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl)
1299 struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, gsm->ftype);
1302 msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */
1303 memcpy(msg->data + 1, ctrl->data, ctrl->len);
1304 gsm_data_queue(gsm->dlci[0], msg);
1308 * gsm_control_retransmit - retransmit a control frame
1309 * @t: timer contained in our gsm object
1311 * Called off the T2 timer expiry in order to retransmit control frames
1312 * that have been lost in the system somewhere. The control_lock protects
1313 * us from colliding with another sender or a receive completion event.
1314 * In that situation the timer may still occur in a small window but
1315 * gsm->pending_cmd will be NULL and we just let the timer expire.
1318 static void gsm_control_retransmit(struct timer_list *t)
1320 struct gsm_mux *gsm = from_timer(gsm, t, t2_timer);
1321 struct gsm_control *ctrl;
1322 unsigned long flags;
1323 spin_lock_irqsave(&gsm->control_lock, flags);
1324 ctrl = gsm->pending_cmd;
1327 if (gsm->cretries == 0) {
1328 gsm->pending_cmd = NULL;
1329 ctrl->error = -ETIMEDOUT;
1331 spin_unlock_irqrestore(&gsm->control_lock, flags);
1332 wake_up(&gsm->event);
1335 gsm_control_transmit(gsm, ctrl);
1336 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1338 spin_unlock_irqrestore(&gsm->control_lock, flags);
1342 * gsm_control_send - send a control frame on DLCI 0
1343 * @gsm: the GSM channel
1344 * @command: command to send including CR bit
1345 * @data: bytes of data (must be kmalloced)
1346 * @clen: length of the block to send
1348 * Queue and dispatch a control command. Only one command can be
1349 * active at a time. In theory more can be outstanding but the matching
1350 * gets really complicated so for now stick to one outstanding.
1353 static struct gsm_control *gsm_control_send(struct gsm_mux *gsm,
1354 unsigned int command, u8 *data, int clen)
1356 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control),
1358 unsigned long flags;
1362 wait_event(gsm->event, gsm->pending_cmd == NULL);
1363 spin_lock_irqsave(&gsm->control_lock, flags);
1364 if (gsm->pending_cmd != NULL) {
1365 spin_unlock_irqrestore(&gsm->control_lock, flags);
1368 ctrl->cmd = command;
1371 gsm->pending_cmd = ctrl;
1373 /* If DLCI0 is in ADM mode skip retries, it won't respond */
1374 if (gsm->dlci[0]->mode == DLCI_MODE_ADM)
1377 gsm->cretries = gsm->n2;
1379 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1380 gsm_control_transmit(gsm, ctrl);
1381 spin_unlock_irqrestore(&gsm->control_lock, flags);
1386 * gsm_control_wait - wait for a control to finish
1388 * @control: control we are waiting on
1390 * Waits for the control to complete or time out. Frees any used
1391 * resources and returns 0 for success, or an error if the remote
1392 * rejected or ignored the request.
1395 static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
1398 wait_event(gsm->event, control->done == 1);
1399 err = control->error;
1406 * DLCI level handling: Needs krefs
1410 * State transitions and timers
1414 * gsm_dlci_close - a DLCI has closed
1415 * @dlci: DLCI that closed
1417 * Perform processing when moving a DLCI into closed state. If there
1418 * is an attached tty this is hung up
1421 static void gsm_dlci_close(struct gsm_dlci *dlci)
1423 del_timer(&dlci->t1);
1425 pr_debug("DLCI %d goes closed.\n", dlci->addr);
1426 dlci->state = DLCI_CLOSED;
1427 if (dlci->addr != 0) {
1428 tty_port_tty_hangup(&dlci->port, false);
1429 kfifo_reset(&dlci->fifo);
1431 dlci->gsm->dead = true;
1432 wake_up(&dlci->gsm->event);
1433 /* A DLCI 0 close is a MUX termination so we need to kick that
1434 back to userspace somehow */
1438 * gsm_dlci_open - a DLCI has opened
1439 * @dlci: DLCI that opened
1441 * Perform processing when moving a DLCI into open state.
1444 static void gsm_dlci_open(struct gsm_dlci *dlci)
1446 /* Note that SABM UA .. SABM UA first UA lost can mean that we go
1448 del_timer(&dlci->t1);
1449 /* This will let a tty open continue */
1450 dlci->state = DLCI_OPEN;
1452 pr_debug("DLCI %d goes open.\n", dlci->addr);
1453 wake_up(&dlci->gsm->event);
1457 * gsm_dlci_t1 - T1 timer expiry
1458 * @t: timer contained in the DLCI that opened
1460 * The T1 timer handles retransmits of control frames (essentially of
1461 * SABM and DISC). We resend the command until the retry count runs out
1462 * in which case an opening port goes back to closed and a closing port
1463 * is simply put into closed state (any further frames from the other
1464 * end will get a DM response)
1466 * Some control dlci can stay in ADM mode with other dlci working just
1467 * fine. In that case we can just keep the control dlci open after the
1468 * DLCI_OPENING retries time out.
1471 static void gsm_dlci_t1(struct timer_list *t)
1473 struct gsm_dlci *dlci = from_timer(dlci, t, t1);
1474 struct gsm_mux *gsm = dlci->gsm;
1476 switch (dlci->state) {
1479 if (dlci->retries) {
1480 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1481 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1482 } else if (!dlci->addr && gsm->control == (DM | PF)) {
1484 pr_info("DLCI %d opening in ADM mode.\n",
1486 dlci->mode = DLCI_MODE_ADM;
1487 gsm_dlci_open(dlci);
1489 gsm_dlci_close(dlci);
1495 if (dlci->retries) {
1496 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1497 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1499 gsm_dlci_close(dlci);
1502 pr_debug("%s: unhandled state: %d\n", __func__, dlci->state);
1508 * gsm_dlci_begin_open - start channel open procedure
1509 * @dlci: DLCI to open
1511 * Commence opening a DLCI from the Linux side. We issue SABM messages
1512 * to the modem which should then reply with a UA or ADM, at which point
1513 * we will move into open state. Opening is done asynchronously with retry
1514 * running off timers and the responses.
1517 static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
1519 struct gsm_mux *gsm = dlci->gsm;
1520 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING)
1522 dlci->retries = gsm->n2;
1523 dlci->state = DLCI_OPENING;
1524 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1525 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1529 * gsm_dlci_begin_close - start channel open procedure
1530 * @dlci: DLCI to open
1532 * Commence closing a DLCI from the Linux side. We issue DISC messages
1533 * to the modem which should then reply with a UA, at which point we
1534 * will move into closed state. Closing is done asynchronously with retry
1535 * off timers. We may also receive a DM reply from the other end which
1536 * indicates the channel was already closed.
1539 static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
1541 struct gsm_mux *gsm = dlci->gsm;
1542 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
1544 dlci->retries = gsm->n2;
1545 dlci->state = DLCI_CLOSING;
1546 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1547 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1551 * gsm_dlci_data - data arrived
1553 * @data: block of bytes received
1554 * @clen: length of received block
1556 * A UI or UIH frame has arrived which contains data for a channel
1557 * other than the control channel. If the relevant virtual tty is
1558 * open we shovel the bits down it, if not we drop them.
1561 static void gsm_dlci_data(struct gsm_dlci *dlci, const u8 *data, int clen)
1564 struct tty_port *port = &dlci->port;
1565 struct tty_struct *tty;
1566 unsigned int modem = 0;
1570 pr_debug("%d bytes for tty\n", len);
1571 switch (dlci->adaption) {
1572 /* Unsupported types */
1573 case 4: /* Packetised interruptible data */
1575 case 3: /* Packetised uininterruptible voice/data */
1577 case 2: /* Asynchronous serial with line state in each frame */
1578 while (gsm_read_ea(&modem, *data++) == 0) {
1583 tty = tty_port_tty_get(port);
1585 gsm_process_modem(tty, dlci, modem, clen);
1589 case 1: /* Line state will go via DLCI 0 controls only */
1591 tty_insert_flip_string(port, data, len);
1592 tty_flip_buffer_push(port);
1597 * gsm_dlci_command - data arrived on control channel
1599 * @data: block of bytes received
1600 * @len: length of received block
1602 * A UI or UIH frame has arrived which contains data for DLCI 0 the
1603 * control channel. This should contain a command EA followed by
1604 * control data bytes. The command EA contains a command/response bit
1605 * and we divide up the work accordingly.
1608 static void gsm_dlci_command(struct gsm_dlci *dlci, const u8 *data, int len)
1610 /* See what command is involved */
1611 unsigned int command = 0;
1613 if (gsm_read_ea(&command, *data++) == 1) {
1616 /* FIXME: this is properly an EA */
1618 /* Malformed command ? */
1622 gsm_control_message(dlci->gsm, command,
1625 gsm_control_response(dlci->gsm, command,
1633 * Allocate/Free DLCI channels
1637 * gsm_dlci_alloc - allocate a DLCI
1639 * @addr: address of the DLCI
1641 * Allocate and install a new DLCI object into the GSM mux.
1643 * FIXME: review locking races
1646 static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
1648 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC);
1651 spin_lock_init(&dlci->lock);
1652 mutex_init(&dlci->mutex);
1653 if (kfifo_alloc(&dlci->fifo, 4096, GFP_KERNEL) < 0) {
1658 skb_queue_head_init(&dlci->skb_list);
1659 timer_setup(&dlci->t1, gsm_dlci_t1, 0);
1660 tty_port_init(&dlci->port);
1661 dlci->port.ops = &gsm_port_ops;
1664 dlci->adaption = gsm->adaption;
1665 dlci->state = DLCI_CLOSED;
1667 dlci->data = gsm_dlci_data;
1669 dlci->data = gsm_dlci_command;
1670 gsm->dlci[addr] = dlci;
1675 * gsm_dlci_free - free DLCI
1676 * @port: tty port for DLCI to free
1682 static void gsm_dlci_free(struct tty_port *port)
1684 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
1686 del_timer_sync(&dlci->t1);
1687 dlci->gsm->dlci[dlci->addr] = NULL;
1688 kfifo_free(&dlci->fifo);
1689 while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
1690 dev_kfree_skb(dlci->skb);
1694 static inline void dlci_get(struct gsm_dlci *dlci)
1696 tty_port_get(&dlci->port);
1699 static inline void dlci_put(struct gsm_dlci *dlci)
1701 tty_port_put(&dlci->port);
1704 static void gsm_destroy_network(struct gsm_dlci *dlci);
1707 * gsm_dlci_release - release DLCI
1708 * @dlci: DLCI to destroy
1710 * Release a DLCI. Actual free is deferred until either
1711 * mux is closed or tty is closed - whichever is last.
1715 static void gsm_dlci_release(struct gsm_dlci *dlci)
1717 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1719 mutex_lock(&dlci->mutex);
1720 gsm_destroy_network(dlci);
1721 mutex_unlock(&dlci->mutex);
1725 tty_port_tty_set(&dlci->port, NULL);
1728 dlci->state = DLCI_CLOSED;
1733 * LAPBish link layer logic
1737 * gsm_queue - a GSM frame is ready to process
1738 * @gsm: pointer to our gsm mux
1740 * At this point in time a frame has arrived and been demangled from
1741 * the line encoding. All the differences between the encodings have
1742 * been handled below us and the frame is unpacked into the structures.
1743 * The fcs holds the header FCS but any data FCS must be added here.
1746 static void gsm_queue(struct gsm_mux *gsm)
1748 struct gsm_dlci *dlci;
1751 /* We have to sneak a look at the packet body to do the FCS.
1752 A somewhat layering violation in the spec */
1754 if ((gsm->control & ~PF) == UI)
1755 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len);
1756 if (gsm->encoding == 0) {
1757 /* WARNING: gsm->received_fcs is used for
1758 gsm->encoding = 0 only.
1759 In this case it contain the last piece of data
1760 required to generate final CRC */
1761 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs);
1763 if (gsm->fcs != GOOD_FCS) {
1766 pr_debug("BAD FCS %02x\n", gsm->fcs);
1769 address = gsm->address >> 1;
1770 if (address >= NUM_DLCI)
1773 cr = gsm->address & 1; /* C/R bit */
1775 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
1777 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */
1778 dlci = gsm->dlci[address];
1780 switch (gsm->control) {
1785 dlci = gsm_dlci_alloc(gsm, address);
1789 gsm_response(gsm, address, DM);
1791 gsm_response(gsm, address, UA);
1792 gsm_dlci_open(dlci);
1798 if (dlci == NULL || dlci->state == DLCI_CLOSED) {
1799 gsm_response(gsm, address, DM);
1802 /* Real close complete */
1803 gsm_response(gsm, address, UA);
1804 gsm_dlci_close(dlci);
1808 if (cr == 0 || dlci == NULL)
1810 switch (dlci->state) {
1812 gsm_dlci_close(dlci);
1815 gsm_dlci_open(dlci);
1818 pr_debug("%s: unhandled state: %d\n", __func__,
1823 case DM: /* DM can be valid unsolicited */
1829 gsm_dlci_close(dlci);
1839 if (dlci == NULL || dlci->state != DLCI_OPEN) {
1840 gsm_command(gsm, address, DM|PF);
1843 dlci->data(dlci, gsm->buf, gsm->len);
1856 * gsm0_receive - perform processing for non-transparency
1857 * @gsm: gsm data for this ldisc instance
1860 * Receive bytes in gsm mode 0
1863 static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
1867 switch (gsm->state) {
1868 case GSM_SEARCH: /* SOF marker */
1869 if (c == GSM0_SOF) {
1870 gsm->state = GSM_ADDRESS;
1873 gsm->fcs = INIT_FCS;
1876 case GSM_ADDRESS: /* Address EA */
1877 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1878 if (gsm_read_ea(&gsm->address, c))
1879 gsm->state = GSM_CONTROL;
1881 case GSM_CONTROL: /* Control Byte */
1882 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1884 gsm->state = GSM_LEN0;
1886 case GSM_LEN0: /* Length EA */
1887 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1888 if (gsm_read_ea(&gsm->len, c)) {
1889 if (gsm->len > gsm->mru) {
1891 gsm->state = GSM_SEARCH;
1896 gsm->state = GSM_FCS;
1898 gsm->state = GSM_DATA;
1901 gsm->state = GSM_LEN1;
1904 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1906 gsm->len |= len << 7;
1907 if (gsm->len > gsm->mru) {
1909 gsm->state = GSM_SEARCH;
1914 gsm->state = GSM_FCS;
1916 gsm->state = GSM_DATA;
1918 case GSM_DATA: /* Data */
1919 gsm->buf[gsm->count++] = c;
1920 if (gsm->count == gsm->len)
1921 gsm->state = GSM_FCS;
1923 case GSM_FCS: /* FCS follows the packet */
1924 gsm->received_fcs = c;
1926 gsm->state = GSM_SSOF;
1929 if (c == GSM0_SOF) {
1930 gsm->state = GSM_SEARCH;
1935 pr_debug("%s: unhandled state: %d\n", __func__, gsm->state);
1941 * gsm1_receive - perform processing for non-transparency
1942 * @gsm: gsm data for this ldisc instance
1945 * Receive bytes in mode 1 (Advanced option)
1948 static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
1950 if (c == GSM1_SOF) {
1951 /* EOF is only valid in frame if we have got to the data state
1952 and received at least one byte (the FCS) */
1953 if (gsm->state == GSM_DATA && gsm->count) {
1954 /* Extract the FCS */
1956 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
1957 gsm->len = gsm->count;
1959 gsm->state = GSM_START;
1962 /* Any partial frame was a runt so go back to start */
1963 if (gsm->state != GSM_START) {
1965 gsm->state = GSM_START;
1967 /* A SOF in GSM_START means we are still reading idling or
1972 if (c == GSM1_ESCAPE) {
1977 /* Only an unescaped SOF gets us out of GSM search */
1978 if (gsm->state == GSM_SEARCH)
1982 c ^= GSM1_ESCAPE_BITS;
1983 gsm->escape = false;
1985 switch (gsm->state) {
1986 case GSM_START: /* First byte after SOF */
1988 gsm->state = GSM_ADDRESS;
1989 gsm->fcs = INIT_FCS;
1991 case GSM_ADDRESS: /* Address continuation */
1992 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1993 if (gsm_read_ea(&gsm->address, c))
1994 gsm->state = GSM_CONTROL;
1996 case GSM_CONTROL: /* Control Byte */
1997 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2000 gsm->state = GSM_DATA;
2002 case GSM_DATA: /* Data */
2003 if (gsm->count > gsm->mru) { /* Allow one for the FCS */
2004 gsm->state = GSM_OVERRUN;
2007 gsm->buf[gsm->count++] = c;
2009 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */
2012 pr_debug("%s: unhandled state: %d\n", __func__, gsm->state);
2018 * gsm_error - handle tty error
2020 * @data: byte received (may be invalid)
2021 * @flag: error received
2023 * Handle an error in the receipt of data for a frame. Currently we just
2024 * go back to hunting for a SOF.
2026 * FIXME: better diagnostics ?
2029 static void gsm_error(struct gsm_mux *gsm,
2030 unsigned char data, unsigned char flag)
2032 gsm->state = GSM_SEARCH;
2036 static int gsm_disconnect(struct gsm_mux *gsm)
2038 struct gsm_dlci *dlci = gsm->dlci[0];
2039 struct gsm_control *gc;
2044 /* In theory disconnecting DLCI 0 is sufficient but for some
2045 modems this is apparently not the case. */
2046 gc = gsm_control_send(gsm, CMD_CLD, NULL, 0);
2048 gsm_control_wait(gsm, gc);
2050 del_timer_sync(&gsm->t2_timer);
2051 /* Now we are sure T2 has stopped */
2053 gsm_dlci_begin_close(dlci);
2054 wait_event_interruptible(gsm->event,
2055 dlci->state == DLCI_CLOSED);
2057 if (signal_pending(current))
2064 * gsm_cleanup_mux - generic GSM protocol cleanup
2067 * Clean up the bits of the mux which are the same for all framing
2068 * protocols. Remove the mux from the mux table, stop all the timers
2069 * and then shut down each device hanging up the channels as we go.
2072 static void gsm_cleanup_mux(struct gsm_mux *gsm)
2075 struct gsm_dlci *dlci = gsm->dlci[0];
2076 struct gsm_msg *txq, *ntxq;
2080 spin_lock(&gsm_mux_lock);
2081 for (i = 0; i < MAX_MUX; i++) {
2082 if (gsm_mux[i] == gsm) {
2087 spin_unlock(&gsm_mux_lock);
2088 /* open failed before registering => nothing to do */
2092 del_timer_sync(&gsm->t2_timer);
2093 /* Now we are sure T2 has stopped */
2097 /* Free up any link layer users */
2098 mutex_lock(&gsm->mutex);
2099 for (i = 0; i < NUM_DLCI; i++)
2101 gsm_dlci_release(gsm->dlci[i]);
2102 mutex_unlock(&gsm->mutex);
2103 /* Now wipe the queues */
2104 list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list)
2106 INIT_LIST_HEAD(&gsm->tx_list);
2110 * gsm_activate_mux - generic GSM setup
2113 * Set up the bits of the mux which are the same for all framing
2114 * protocols. Add the mux to the mux table so it can be opened and
2115 * finally kick off connecting to DLCI 0 on the modem.
2118 static int gsm_activate_mux(struct gsm_mux *gsm)
2120 struct gsm_dlci *dlci;
2123 timer_setup(&gsm->t2_timer, gsm_control_retransmit, 0);
2124 init_waitqueue_head(&gsm->event);
2125 spin_lock_init(&gsm->control_lock);
2126 spin_lock_init(&gsm->tx_lock);
2128 if (gsm->encoding == 0)
2129 gsm->receive = gsm0_receive;
2131 gsm->receive = gsm1_receive;
2133 spin_lock(&gsm_mux_lock);
2134 for (i = 0; i < MAX_MUX; i++) {
2135 if (gsm_mux[i] == NULL) {
2141 spin_unlock(&gsm_mux_lock);
2145 dlci = gsm_dlci_alloc(gsm, 0);
2148 gsm->dead = false; /* Tty opens are now permissible */
2153 * gsm_free_mux - free up a mux
2156 * Dispose of allocated resources for a dead mux
2158 static void gsm_free_mux(struct gsm_mux *gsm)
2160 kfree(gsm->txframe);
2166 * gsm_free_muxr - free up a mux
2167 * @ref: kreference to the mux to free
2169 * Dispose of allocated resources for a dead mux
2171 static void gsm_free_muxr(struct kref *ref)
2173 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref);
2177 static inline void mux_get(struct gsm_mux *gsm)
2179 kref_get(&gsm->ref);
2182 static inline void mux_put(struct gsm_mux *gsm)
2184 kref_put(&gsm->ref, gsm_free_muxr);
2187 static inline unsigned int mux_num_to_base(struct gsm_mux *gsm)
2189 return gsm->num * NUM_DLCI;
2192 static inline unsigned int mux_line_to_num(unsigned int line)
2194 return line / NUM_DLCI;
2198 * gsm_alloc_mux - allocate a mux
2200 * Creates a new mux ready for activation.
2203 static struct gsm_mux *gsm_alloc_mux(void)
2205 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
2208 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL);
2209 if (gsm->buf == NULL) {
2213 gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL);
2214 if (gsm->txframe == NULL) {
2219 spin_lock_init(&gsm->lock);
2220 mutex_init(&gsm->mutex);
2221 kref_init(&gsm->ref);
2222 INIT_LIST_HEAD(&gsm->tx_list);
2230 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
2232 gsm->dead = true; /* Avoid early tty opens */
2237 static void gsm_copy_config_values(struct gsm_mux *gsm,
2238 struct gsm_config *c)
2240 memset(c, 0, sizeof(*c));
2241 c->adaption = gsm->adaption;
2242 c->encapsulation = gsm->encoding;
2243 c->initiator = gsm->initiator;
2246 c->t3 = 0; /* Not supported */
2248 if (gsm->ftype == UIH)
2252 pr_debug("Ftype %d i %d\n", gsm->ftype, c->i);
2258 static int gsm_config(struct gsm_mux *gsm, struct gsm_config *c)
2261 int need_restart = 0;
2263 /* Stuff we don't support yet - UI or I frame transport, windowing */
2264 if ((c->adaption != 1 && c->adaption != 2) || c->k)
2266 /* Check the MRU/MTU range looks sane */
2267 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8)
2271 if (c->encapsulation > 1) /* Basic, advanced, no I */
2273 if (c->initiator > 1)
2275 if (c->i == 0 || c->i > 2) /* UIH and UI only */
2278 * See what is needed for reconfiguration
2282 if (c->t1 != 0 && c->t1 != gsm->t1)
2284 if (c->t2 != 0 && c->t2 != gsm->t2)
2286 if (c->encapsulation != gsm->encoding)
2288 if (c->adaption != gsm->adaption)
2291 if (c->initiator != gsm->initiator)
2293 if (c->mru != gsm->mru)
2295 if (c->mtu != gsm->mtu)
2299 * Close down what is needed, restart and initiate the new
2303 if (need_close || need_restart) {
2306 ret = gsm_disconnect(gsm);
2312 gsm_cleanup_mux(gsm);
2314 gsm->initiator = c->initiator;
2317 gsm->encoding = c->encapsulation;
2318 gsm->adaption = c->adaption;
2332 * FIXME: We need to separate activation/deactivation from adding
2333 * and removing from the mux array
2336 gsm_activate_mux(gsm);
2337 if (gsm->initiator && need_close)
2338 gsm_dlci_begin_open(gsm->dlci[0]);
2343 * gsmld_output - write to link
2345 * @data: bytes to output
2348 * Write a block of data from the GSM mux to the data channel. This
2349 * will eventually be serialized from above but at the moment isn't.
2352 static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
2354 if (tty_write_room(gsm->tty) < len) {
2355 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
2359 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET,
2361 gsm->tty->ops->write(gsm->tty, data, len);
2366 * gsmld_attach_gsm - mode set up
2367 * @tty: our tty structure
2370 * Set up the MUX for basic mode and commence connecting to the
2371 * modem. Currently called from the line discipline set up but
2372 * will need moving to an ioctl path.
2375 static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2380 gsm->tty = tty_kref_get(tty);
2381 ret = gsm_activate_mux(gsm);
2383 tty_kref_put(gsm->tty);
2385 /* Don't register device 0 - this is the control channel and not
2386 a usable tty interface */
2387 base = mux_num_to_base(gsm); /* Base for this MUX */
2388 for (i = 1; i < NUM_DLCI; i++) {
2391 dev = tty_register_device(gsm_tty_driver,
2394 for (i--; i >= 1; i--)
2395 tty_unregister_device(gsm_tty_driver,
2397 return PTR_ERR(dev);
2406 * gsmld_detach_gsm - stop doing 0710 mux
2407 * @tty: tty attached to the mux
2410 * Shutdown and then clean up the resources used by the line discipline
2413 static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2415 unsigned int base = mux_num_to_base(gsm); /* Base for this MUX */
2418 WARN_ON(tty != gsm->tty);
2419 for (i = 1; i < NUM_DLCI; i++)
2420 tty_unregister_device(gsm_tty_driver, base + i);
2421 gsm_cleanup_mux(gsm);
2422 tty_kref_put(gsm->tty);
2426 static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
2427 const char *fp, int count)
2429 struct gsm_mux *gsm = tty->disc_data;
2430 char flags = TTY_NORMAL;
2433 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET,
2436 for (; count; count--, cp++) {
2441 gsm->receive(gsm, *cp);
2447 gsm_error(gsm, *cp, flags);
2450 WARN_ONCE(1, "%s: unknown flag %d\n",
2451 tty_name(tty), flags);
2455 /* FASYNC if needed ? */
2456 /* If clogged call tty_throttle(tty); */
2460 * gsmld_flush_buffer - clean input queue
2461 * @tty: terminal device
2463 * Flush the input buffer. Called when the line discipline is
2464 * being closed, when the tty layer wants the buffer flushed (eg
2468 static void gsmld_flush_buffer(struct tty_struct *tty)
2473 * gsmld_close - close the ldisc for this tty
2476 * Called from the terminal layer when this line discipline is
2477 * being shut down, either because of a close or becsuse of a
2478 * discipline change. The function will not be called while other
2479 * ldisc methods are in progress.
2482 static void gsmld_close(struct tty_struct *tty)
2484 struct gsm_mux *gsm = tty->disc_data;
2486 gsmld_detach_gsm(tty, gsm);
2488 gsmld_flush_buffer(tty);
2489 /* Do other clean up here */
2494 * gsmld_open - open an ldisc
2495 * @tty: terminal to open
2497 * Called when this line discipline is being attached to the
2498 * terminal device. Can sleep. Called serialized so that no
2499 * other events will occur in parallel. No further open will occur
2503 static int gsmld_open(struct tty_struct *tty)
2505 struct gsm_mux *gsm;
2508 if (tty->ops->write == NULL)
2511 /* Attach our ldisc data */
2512 gsm = gsm_alloc_mux();
2516 tty->disc_data = gsm;
2517 tty->receive_room = 65536;
2519 /* Attach the initial passive connection */
2522 ret = gsmld_attach_gsm(tty, gsm);
2524 gsm_cleanup_mux(gsm);
2531 * gsmld_write_wakeup - asynchronous I/O notifier
2534 * Required for the ptys, serial driver etc. since processes
2535 * that attach themselves to the master and rely on ASYNC
2536 * IO must be woken up
2539 static void gsmld_write_wakeup(struct tty_struct *tty)
2541 struct gsm_mux *gsm = tty->disc_data;
2542 unsigned long flags;
2545 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2546 spin_lock_irqsave(&gsm->tx_lock, flags);
2547 gsm_data_kick(gsm, NULL);
2548 if (gsm->tx_bytes < TX_THRESH_LO) {
2549 gsm_dlci_data_sweep(gsm);
2551 spin_unlock_irqrestore(&gsm->tx_lock, flags);
2555 * gsmld_read - read function for tty
2557 * @file: file object
2558 * @buf: userspace buffer pointer
2563 * Perform reads for the line discipline. We are guaranteed that the
2564 * line discipline will not be closed under us but we may get multiple
2565 * parallel readers and must handle this ourselves. We may also get
2566 * a hangup. Always called in user context, may sleep.
2568 * This code must be sure never to sleep through a hangup.
2571 static ssize_t gsmld_read(struct tty_struct *tty, struct file *file,
2572 unsigned char *buf, size_t nr,
2573 void **cookie, unsigned long offset)
2579 * gsmld_write - write function for tty
2581 * @file: file object
2582 * @buf: userspace buffer pointer
2585 * Called when the owner of the device wants to send a frame
2586 * itself (or some other control data). The data is transferred
2587 * as-is and must be properly framed and checksummed as appropriate
2588 * by userspace. Frames are either sent whole or not at all as this
2589 * avoids pain user side.
2592 static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
2593 const unsigned char *buf, size_t nr)
2595 int space = tty_write_room(tty);
2597 return tty->ops->write(tty, buf, nr);
2598 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2603 * gsmld_poll - poll method for N_GSM0710
2604 * @tty: terminal device
2605 * @file: file accessing it
2608 * Called when the line discipline is asked to poll() for data or
2609 * for special events. This code is not serialized with respect to
2610 * other events save open/close.
2612 * This code must be sure never to sleep through a hangup.
2613 * Called without the kernel lock held - fine
2616 static __poll_t gsmld_poll(struct tty_struct *tty, struct file *file,
2620 struct gsm_mux *gsm = tty->disc_data;
2622 poll_wait(file, &tty->read_wait, wait);
2623 poll_wait(file, &tty->write_wait, wait);
2624 if (tty_hung_up_p(file))
2626 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
2627 mask |= EPOLLOUT | EPOLLWRNORM;
2633 static int gsmld_ioctl(struct tty_struct *tty, struct file *file,
2634 unsigned int cmd, unsigned long arg)
2636 struct gsm_config c;
2637 struct gsm_mux *gsm = tty->disc_data;
2641 case GSMIOC_GETCONF:
2642 gsm_copy_config_values(gsm, &c);
2643 if (copy_to_user((void __user *)arg, &c, sizeof(c)))
2646 case GSMIOC_SETCONF:
2647 if (copy_from_user(&c, (void __user *)arg, sizeof(c)))
2649 return gsm_config(gsm, &c);
2650 case GSMIOC_GETFIRST:
2651 base = mux_num_to_base(gsm);
2652 return put_user(base + 1, (__u32 __user *)arg);
2654 return n_tty_ioctl_helper(tty, file, cmd, arg);
2663 static int gsm_mux_net_open(struct net_device *net)
2665 pr_debug("%s called\n", __func__);
2666 netif_start_queue(net);
2670 static int gsm_mux_net_close(struct net_device *net)
2672 netif_stop_queue(net);
2676 static void dlci_net_free(struct gsm_dlci *dlci)
2682 dlci->adaption = dlci->prev_adaption;
2683 dlci->data = dlci->prev_data;
2684 free_netdev(dlci->net);
2687 static void net_free(struct kref *ref)
2689 struct gsm_mux_net *mux_net;
2690 struct gsm_dlci *dlci;
2692 mux_net = container_of(ref, struct gsm_mux_net, ref);
2693 dlci = mux_net->dlci;
2696 unregister_netdev(dlci->net);
2697 dlci_net_free(dlci);
2701 static inline void muxnet_get(struct gsm_mux_net *mux_net)
2703 kref_get(&mux_net->ref);
2706 static inline void muxnet_put(struct gsm_mux_net *mux_net)
2708 kref_put(&mux_net->ref, net_free);
2711 static netdev_tx_t gsm_mux_net_start_xmit(struct sk_buff *skb,
2712 struct net_device *net)
2714 struct gsm_mux_net *mux_net = netdev_priv(net);
2715 struct gsm_dlci *dlci = mux_net->dlci;
2716 muxnet_get(mux_net);
2718 skb_queue_head(&dlci->skb_list, skb);
2719 net->stats.tx_packets++;
2720 net->stats.tx_bytes += skb->len;
2721 gsm_dlci_data_kick(dlci);
2722 /* And tell the kernel when the last transmit started. */
2723 netif_trans_update(net);
2724 muxnet_put(mux_net);
2725 return NETDEV_TX_OK;
2728 /* called when a packet did not ack after watchdogtimeout */
2729 static void gsm_mux_net_tx_timeout(struct net_device *net, unsigned int txqueue)
2731 /* Tell syslog we are hosed. */
2732 dev_dbg(&net->dev, "Tx timed out.\n");
2734 /* Update statistics */
2735 net->stats.tx_errors++;
2738 static void gsm_mux_rx_netchar(struct gsm_dlci *dlci,
2739 const unsigned char *in_buf, int size)
2741 struct net_device *net = dlci->net;
2742 struct sk_buff *skb;
2743 struct gsm_mux_net *mux_net = netdev_priv(net);
2744 muxnet_get(mux_net);
2746 /* Allocate an sk_buff */
2747 skb = dev_alloc_skb(size + NET_IP_ALIGN);
2749 /* We got no receive buffer. */
2750 net->stats.rx_dropped++;
2751 muxnet_put(mux_net);
2754 skb_reserve(skb, NET_IP_ALIGN);
2755 skb_put_data(skb, in_buf, size);
2758 skb->protocol = htons(ETH_P_IP);
2760 /* Ship it off to the kernel */
2763 /* update out statistics */
2764 net->stats.rx_packets++;
2765 net->stats.rx_bytes += size;
2766 muxnet_put(mux_net);
2770 static void gsm_mux_net_init(struct net_device *net)
2772 static const struct net_device_ops gsm_netdev_ops = {
2773 .ndo_open = gsm_mux_net_open,
2774 .ndo_stop = gsm_mux_net_close,
2775 .ndo_start_xmit = gsm_mux_net_start_xmit,
2776 .ndo_tx_timeout = gsm_mux_net_tx_timeout,
2779 net->netdev_ops = &gsm_netdev_ops;
2781 /* fill in the other fields */
2782 net->watchdog_timeo = GSM_NET_TX_TIMEOUT;
2783 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
2784 net->type = ARPHRD_NONE;
2785 net->tx_queue_len = 10;
2789 /* caller holds the dlci mutex */
2790 static void gsm_destroy_network(struct gsm_dlci *dlci)
2792 struct gsm_mux_net *mux_net;
2794 pr_debug("destroy network interface\n");
2797 mux_net = netdev_priv(dlci->net);
2798 muxnet_put(mux_net);
2802 /* caller holds the dlci mutex */
2803 static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
2807 struct net_device *net;
2808 struct gsm_mux_net *mux_net;
2810 if (!capable(CAP_NET_ADMIN))
2813 /* Already in a non tty mode */
2814 if (dlci->adaption > 2)
2817 if (nc->protocol != htons(ETH_P_IP))
2818 return -EPROTONOSUPPORT;
2820 if (nc->adaption != 3 && nc->adaption != 4)
2821 return -EPROTONOSUPPORT;
2823 pr_debug("create network interface\n");
2826 if (nc->if_name[0] != '\0')
2827 netname = nc->if_name;
2828 net = alloc_netdev(sizeof(struct gsm_mux_net), netname,
2829 NET_NAME_UNKNOWN, gsm_mux_net_init);
2831 pr_err("alloc_netdev failed\n");
2834 net->mtu = dlci->gsm->mtu;
2836 net->max_mtu = dlci->gsm->mtu;
2837 mux_net = netdev_priv(net);
2838 mux_net->dlci = dlci;
2839 kref_init(&mux_net->ref);
2840 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */
2842 /* reconfigure dlci for network */
2843 dlci->prev_adaption = dlci->adaption;
2844 dlci->prev_data = dlci->data;
2845 dlci->adaption = nc->adaption;
2846 dlci->data = gsm_mux_rx_netchar;
2849 pr_debug("register netdev\n");
2850 retval = register_netdev(net);
2852 pr_err("network register fail %d\n", retval);
2853 dlci_net_free(dlci);
2856 return net->ifindex; /* return network index */
2859 /* Line discipline for real tty */
2860 static struct tty_ldisc_ops tty_ldisc_packet = {
2861 .owner = THIS_MODULE,
2865 .close = gsmld_close,
2866 .flush_buffer = gsmld_flush_buffer,
2868 .write = gsmld_write,
2869 .ioctl = gsmld_ioctl,
2871 .receive_buf = gsmld_receive_buf,
2872 .write_wakeup = gsmld_write_wakeup
2881 static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk)
2884 struct gsm_control *ctrl;
2890 modembits[0] = len << 1 | EA; /* Data bytes */
2891 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */
2892 modembits[2] = gsm_encode_modem(dlci) << 1 | EA;
2894 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */
2895 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1);
2898 return gsm_control_wait(dlci->gsm, ctrl);
2901 static int gsm_carrier_raised(struct tty_port *port)
2903 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2904 struct gsm_mux *gsm = dlci->gsm;
2906 /* Not yet open so no carrier info */
2907 if (dlci->state != DLCI_OPEN)
2913 * Basic mode with control channel in ADM mode may not respond
2914 * to CMD_MSC at all and modem_rx is empty.
2916 if (gsm->encoding == 0 && gsm->dlci[0]->mode == DLCI_MODE_ADM &&
2920 return dlci->modem_rx & TIOCM_CD;
2923 static void gsm_dtr_rts(struct tty_port *port, int onoff)
2925 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2926 unsigned int modem_tx = dlci->modem_tx;
2928 modem_tx |= TIOCM_DTR | TIOCM_RTS;
2930 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
2931 if (modem_tx != dlci->modem_tx) {
2932 dlci->modem_tx = modem_tx;
2933 gsmtty_modem_update(dlci, 0);
2937 static const struct tty_port_operations gsm_port_ops = {
2938 .carrier_raised = gsm_carrier_raised,
2939 .dtr_rts = gsm_dtr_rts,
2940 .destruct = gsm_dlci_free,
2943 static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty)
2945 struct gsm_mux *gsm;
2946 struct gsm_dlci *dlci;
2947 unsigned int line = tty->index;
2948 unsigned int mux = mux_line_to_num(line);
2956 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
2957 if (gsm_mux[mux] == NULL)
2959 if (line == 0 || line > 61) /* 62/63 reserved */
2964 /* If DLCI 0 is not yet fully open return an error.
2965 This is ok from a locking
2966 perspective as we don't have to worry about this
2968 mutex_lock(&gsm->mutex);
2969 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN) {
2970 mutex_unlock(&gsm->mutex);
2973 dlci = gsm->dlci[line];
2976 dlci = gsm_dlci_alloc(gsm, line);
2979 mutex_unlock(&gsm->mutex);
2982 ret = tty_port_install(&dlci->port, driver, tty);
2986 mutex_unlock(&gsm->mutex);
2991 dlci_get(gsm->dlci[0]);
2993 tty->driver_data = dlci;
2994 mutex_unlock(&gsm->mutex);
2999 static int gsmtty_open(struct tty_struct *tty, struct file *filp)
3001 struct gsm_dlci *dlci = tty->driver_data;
3002 struct tty_port *port = &dlci->port;
3005 tty_port_tty_set(port, tty);
3008 /* We could in theory open and close before we wait - eg if we get
3009 a DM straight back. This is ok as that will have caused a hangup */
3010 tty_port_set_initialized(port, 1);
3011 /* Start sending off SABM messages */
3012 gsm_dlci_begin_open(dlci);
3013 /* And wait for virtual carrier */
3014 return tty_port_block_til_ready(port, tty, filp);
3017 static void gsmtty_close(struct tty_struct *tty, struct file *filp)
3019 struct gsm_dlci *dlci = tty->driver_data;
3023 if (dlci->state == DLCI_CLOSED)
3025 mutex_lock(&dlci->mutex);
3026 gsm_destroy_network(dlci);
3027 mutex_unlock(&dlci->mutex);
3028 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
3030 gsm_dlci_begin_close(dlci);
3031 if (tty_port_initialized(&dlci->port) && C_HUPCL(tty))
3032 tty_port_lower_dtr_rts(&dlci->port);
3033 tty_port_close_end(&dlci->port, tty);
3034 tty_port_tty_set(&dlci->port, NULL);
3038 static void gsmtty_hangup(struct tty_struct *tty)
3040 struct gsm_dlci *dlci = tty->driver_data;
3041 if (dlci->state == DLCI_CLOSED)
3043 tty_port_hangup(&dlci->port);
3044 gsm_dlci_begin_close(dlci);
3047 static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf,
3051 struct gsm_dlci *dlci = tty->driver_data;
3052 if (dlci->state == DLCI_CLOSED)
3054 /* Stuff the bytes into the fifo queue */
3055 sent = kfifo_in_locked(&dlci->fifo, buf, len, &dlci->lock);
3056 /* Need to kick the channel */
3057 gsm_dlci_data_kick(dlci);
3061 static unsigned int gsmtty_write_room(struct tty_struct *tty)
3063 struct gsm_dlci *dlci = tty->driver_data;
3064 if (dlci->state == DLCI_CLOSED)
3066 return TX_SIZE - kfifo_len(&dlci->fifo);
3069 static unsigned int gsmtty_chars_in_buffer(struct tty_struct *tty)
3071 struct gsm_dlci *dlci = tty->driver_data;
3072 if (dlci->state == DLCI_CLOSED)
3074 return kfifo_len(&dlci->fifo);
3077 static void gsmtty_flush_buffer(struct tty_struct *tty)
3079 struct gsm_dlci *dlci = tty->driver_data;
3080 if (dlci->state == DLCI_CLOSED)
3082 /* Caution needed: If we implement reliable transport classes
3083 then the data being transmitted can't simply be junked once
3084 it has first hit the stack. Until then we can just blow it
3086 kfifo_reset(&dlci->fifo);
3087 /* Need to unhook this DLCI from the transmit queue logic */
3090 static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
3092 /* The FIFO handles the queue so the kernel will do the right
3093 thing waiting on chars_in_buffer before calling us. No work
3097 static int gsmtty_tiocmget(struct tty_struct *tty)
3099 struct gsm_dlci *dlci = tty->driver_data;
3100 if (dlci->state == DLCI_CLOSED)
3102 return dlci->modem_rx;
3105 static int gsmtty_tiocmset(struct tty_struct *tty,
3106 unsigned int set, unsigned int clear)
3108 struct gsm_dlci *dlci = tty->driver_data;
3109 unsigned int modem_tx = dlci->modem_tx;
3111 if (dlci->state == DLCI_CLOSED)
3116 if (modem_tx != dlci->modem_tx) {
3117 dlci->modem_tx = modem_tx;
3118 return gsmtty_modem_update(dlci, 0);
3124 static int gsmtty_ioctl(struct tty_struct *tty,
3125 unsigned int cmd, unsigned long arg)
3127 struct gsm_dlci *dlci = tty->driver_data;
3128 struct gsm_netconfig nc;
3131 if (dlci->state == DLCI_CLOSED)
3134 case GSMIOC_ENABLE_NET:
3135 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc)))
3137 nc.if_name[IFNAMSIZ-1] = '\0';
3138 /* return net interface index or error code */
3139 mutex_lock(&dlci->mutex);
3140 index = gsm_create_network(dlci, &nc);
3141 mutex_unlock(&dlci->mutex);
3142 if (copy_to_user((void __user *)arg, &nc, sizeof(nc)))
3145 case GSMIOC_DISABLE_NET:
3146 if (!capable(CAP_NET_ADMIN))
3148 mutex_lock(&dlci->mutex);
3149 gsm_destroy_network(dlci);
3150 mutex_unlock(&dlci->mutex);
3153 return -ENOIOCTLCMD;
3157 static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old)
3159 struct gsm_dlci *dlci = tty->driver_data;
3160 if (dlci->state == DLCI_CLOSED)
3162 /* For the moment its fixed. In actual fact the speed information
3163 for the virtual channel can be propogated in both directions by
3164 the RPN control message. This however rapidly gets nasty as we
3165 then have to remap modem signals each way according to whether
3166 our virtual cable is null modem etc .. */
3167 tty_termios_copy_hw(&tty->termios, old);
3170 static void gsmtty_throttle(struct tty_struct *tty)
3172 struct gsm_dlci *dlci = tty->driver_data;
3173 if (dlci->state == DLCI_CLOSED)
3176 dlci->modem_tx &= ~TIOCM_DTR;
3177 dlci->throttled = true;
3178 /* Send an MSC with DTR cleared */
3179 gsmtty_modem_update(dlci, 0);
3182 static void gsmtty_unthrottle(struct tty_struct *tty)
3184 struct gsm_dlci *dlci = tty->driver_data;
3185 if (dlci->state == DLCI_CLOSED)
3188 dlci->modem_tx |= TIOCM_DTR;
3189 dlci->throttled = false;
3190 /* Send an MSC with DTR set */
3191 gsmtty_modem_update(dlci, 0);
3194 static int gsmtty_break_ctl(struct tty_struct *tty, int state)
3196 struct gsm_dlci *dlci = tty->driver_data;
3197 int encode = 0; /* Off */
3198 if (dlci->state == DLCI_CLOSED)
3201 if (state == -1) /* "On indefinitely" - we can't encode this
3204 else if (state > 0) {
3205 encode = state / 200; /* mS to encoding */
3207 encode = 0x0F; /* Best effort */
3209 return gsmtty_modem_update(dlci, encode);
3212 static void gsmtty_cleanup(struct tty_struct *tty)
3214 struct gsm_dlci *dlci = tty->driver_data;
3215 struct gsm_mux *gsm = dlci->gsm;
3218 dlci_put(gsm->dlci[0]);
3222 /* Virtual ttys for the demux */
3223 static const struct tty_operations gsmtty_ops = {
3224 .install = gsmtty_install,
3225 .open = gsmtty_open,
3226 .close = gsmtty_close,
3227 .write = gsmtty_write,
3228 .write_room = gsmtty_write_room,
3229 .chars_in_buffer = gsmtty_chars_in_buffer,
3230 .flush_buffer = gsmtty_flush_buffer,
3231 .ioctl = gsmtty_ioctl,
3232 .throttle = gsmtty_throttle,
3233 .unthrottle = gsmtty_unthrottle,
3234 .set_termios = gsmtty_set_termios,
3235 .hangup = gsmtty_hangup,
3236 .wait_until_sent = gsmtty_wait_until_sent,
3237 .tiocmget = gsmtty_tiocmget,
3238 .tiocmset = gsmtty_tiocmset,
3239 .break_ctl = gsmtty_break_ctl,
3240 .cleanup = gsmtty_cleanup,
3245 static int __init gsm_init(void)
3247 /* Fill in our line protocol discipline, and register it */
3248 int status = tty_register_ldisc(&tty_ldisc_packet);
3250 pr_err("n_gsm: can't register line discipline (err = %d)\n",
3255 gsm_tty_driver = alloc_tty_driver(256);
3256 if (!gsm_tty_driver) {
3257 pr_err("gsm_init: tty allocation failed.\n");
3259 goto err_unreg_ldisc;
3261 gsm_tty_driver->driver_name = "gsmtty";
3262 gsm_tty_driver->name = "gsmtty";
3263 gsm_tty_driver->major = 0; /* Dynamic */
3264 gsm_tty_driver->minor_start = 0;
3265 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
3266 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
3267 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV
3268 | TTY_DRIVER_HARDWARE_BREAK;
3269 gsm_tty_driver->init_termios = tty_std_termios;
3271 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
3272 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
3274 if (tty_register_driver(gsm_tty_driver)) {
3275 pr_err("gsm_init: tty registration failed.\n");
3277 goto err_put_driver;
3279 pr_debug("gsm_init: loaded as %d,%d.\n",
3280 gsm_tty_driver->major, gsm_tty_driver->minor_start);
3283 put_tty_driver(gsm_tty_driver);
3285 tty_unregister_ldisc(&tty_ldisc_packet);
3289 static void __exit gsm_exit(void)
3291 tty_unregister_ldisc(&tty_ldisc_packet);
3292 tty_unregister_driver(gsm_tty_driver);
3293 put_tty_driver(gsm_tty_driver);
3296 module_init(gsm_init);
3297 module_exit(gsm_exit);
3300 MODULE_LICENSE("GPL");
3301 MODULE_ALIAS_LDISC(N_GSM0710);