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>
55 module_param(debug, int, 0600);
57 /* Defaults: these are from the specification */
59 #define T1 10 /* 100mS */
60 #define T2 34 /* 333mS */
61 #define N2 3 /* Retry 3 times */
63 /* Use long timers for testing at low speed with debug on */
70 * Semi-arbitrary buffer size limits. 0710 is normally run with 32-64 byte
71 * limits so this is plenty
75 /* SOF, ADDR, CTRL, LEN1, LEN2, ..., FCS, EOF */
76 #define PROT_OVERHEAD 7
77 #define GSM_NET_TX_TIMEOUT (HZ*10)
80 * struct gsm_mux_net - network interface
81 * @struct gsm_dlci* dlci
83 * Created when net interface is initialized.
87 struct gsm_dlci *dlci;
91 * Each block of data we have queued to go out is in the form of
92 * a gsm_msg which holds everything we need in a link layer independent
97 struct list_head list;
98 u8 addr; /* DLCI address + flags */
99 u8 ctrl; /* Control byte + flags */
100 unsigned int len; /* Length of data block (can be zero) */
101 unsigned char *data; /* Points into buffer but not at the start */
102 unsigned char buffer[0];
106 * Each active data link has a gsm_dlci structure associated which ties
107 * the link layer to an optional tty (if the tty side is open). To avoid
108 * complexity right now these are only ever freed up when the mux is
111 * At the moment we don't free DLCI objects until the mux is torn down
112 * this avoid object life time issues but might be worth review later.
119 #define DLCI_CLOSED 0
120 #define DLCI_OPENING 1 /* Sending SABM not seen UA */
121 #define DLCI_OPEN 2 /* SABM/UA complete */
122 #define DLCI_CLOSING 3 /* Sending DISC not seen UA/DM */
127 #define DLCI_MODE_ABM 0 /* Normal Asynchronous Balanced Mode */
128 #define DLCI_MODE_ADM 1 /* Asynchronous Disconnected Mode */
129 spinlock_t lock; /* Protects the internal state */
130 struct timer_list t1; /* Retransmit timer for SABM and UA */
132 /* Uplink tty if active */
133 struct tty_port port; /* The tty bound to this DLCI if there is one */
134 struct kfifo *fifo; /* Queue fifo for the DLCI */
135 struct kfifo _fifo; /* For new fifo API porting only */
136 int adaption; /* Adaption layer in use */
138 u32 modem_rx; /* Our incoming virtual modem lines */
139 u32 modem_tx; /* Our outgoing modem lines */
140 int dead; /* Refuse re-open */
142 int throttled; /* Private copy of throttle state */
143 int constipated; /* Throttle status for outgoing */
145 struct sk_buff *skb; /* Frame being sent */
146 struct sk_buff_head skb_list; /* Queued frames */
147 /* Data handling callback */
148 void (*data)(struct gsm_dlci *dlci, u8 *data, int len);
149 void (*prev_data)(struct gsm_dlci *dlci, u8 *data, int len);
150 struct net_device *net; /* network interface, if created */
153 /* DLCI 0, 62/63 are special or reserved see gsmtty_open */
158 * DLCI 0 is used to pass control blocks out of band of the data
159 * flow (and with a higher link priority). One command can be outstanding
160 * at a time and we use this structure to manage them. They are created
161 * and destroyed by the user context, and updated by the receive paths
166 u8 cmd; /* Command we are issuing */
167 u8 *data; /* Data for the command in case we retransmit */
168 int len; /* Length of block for retransmission */
169 int done; /* Done flag */
170 int error; /* Error if any */
174 * Each GSM mux we have is represented by this structure. If we are
175 * operating as an ldisc then we use this structure as our ldisc
176 * state. We need to sort out lifetimes and locking with respect
177 * to the gsm mux array. For now we don't free DLCI objects that
178 * have been instantiated until the mux itself is terminated.
180 * To consider further: tty open versus mux shutdown.
184 struct tty_struct *tty; /* The tty our ldisc is bound to */
190 /* Events on the GSM channel */
191 wait_queue_head_t event;
193 /* Bits for GSM mode decoding */
200 #define GSM_ADDRESS 2
201 #define GSM_CONTROL 3
205 #define GSM_OVERRUN 7
210 unsigned int address;
217 u8 *txframe; /* TX framing buffer */
219 /* Methods for the receiver side */
220 void (*receive)(struct gsm_mux *gsm, u8 ch);
221 void (*error)(struct gsm_mux *gsm, u8 ch, u8 flag);
222 /* And transmit side */
223 int (*output)(struct gsm_mux *mux, u8 *data, int len);
228 int initiator; /* Did we initiate connection */
229 int dead; /* Has the mux been shut down */
230 struct gsm_dlci *dlci[NUM_DLCI];
231 int constipated; /* Asked by remote to shut up */
234 unsigned int tx_bytes; /* TX data outstanding */
235 #define TX_THRESH_HI 8192
236 #define TX_THRESH_LO 2048
237 struct list_head tx_list; /* Pending data packets */
239 /* Control messages */
240 struct timer_list t2_timer; /* Retransmit timer for commands */
241 int cretries; /* Command retry counter */
242 struct gsm_control *pending_cmd;/* Our current pending command */
243 spinlock_t control_lock; /* Protects the pending command */
246 int adaption; /* 1 or 2 supported */
247 u8 ftype; /* UI or UIH */
248 int t1, t2; /* Timers in 1/100th of a sec */
249 int n2; /* Retry count */
251 /* Statistics (not currently exposed) */
252 unsigned long bad_fcs;
253 unsigned long malformed;
254 unsigned long io_error;
255 unsigned long bad_size;
256 unsigned long unsupported;
261 * Mux objects - needed so that we can translate a tty index into the
262 * relevant mux and DLCI.
265 #define MAX_MUX 4 /* 256 minors */
266 static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */
267 static spinlock_t gsm_mux_lock;
269 static struct tty_driver *gsm_tty_driver;
272 * This section of the driver logic implements the GSM encodings
273 * both the basic and the 'advanced'. Reliable transport is not
281 /* I is special: the rest are ..*/
292 /* Channel commands */
294 #define CMD_TEST 0x11
297 #define CMD_FCOFF 0x31
300 #define CMD_FCON 0x51
305 /* Virtual modem bits */
312 #define GSM0_SOF 0xF9
313 #define GSM1_SOF 0x7E
314 #define GSM1_ESCAPE 0x7D
315 #define GSM1_ESCAPE_BITS 0x20
318 #define ISO_IEC_646_MASK 0x7F
320 static const struct tty_port_operations gsm_port_ops;
323 * CRC table for GSM 0710
326 static const u8 gsm_fcs8[256] = {
327 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75,
328 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B,
329 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69,
330 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67,
331 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D,
332 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43,
333 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51,
334 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F,
335 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05,
336 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B,
337 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19,
338 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17,
339 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D,
340 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33,
341 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21,
342 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F,
343 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95,
344 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B,
345 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89,
346 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87,
347 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD,
348 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3,
349 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1,
350 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF,
351 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5,
352 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB,
353 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9,
354 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7,
355 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD,
356 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3,
357 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1,
358 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF
361 #define INIT_FCS 0xFF
362 #define GOOD_FCS 0xCF
365 * gsm_fcs_add - update FCS
369 * Update the FCS to include c. Uses the algorithm in the specification
373 static inline u8 gsm_fcs_add(u8 fcs, u8 c)
375 return gsm_fcs8[fcs ^ c];
379 * gsm_fcs_add_block - update FCS for a block
382 * @len: length of buffer
384 * Update the FCS to include c. Uses the algorithm in the specification
388 static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len)
391 fcs = gsm_fcs8[fcs ^ *c++];
396 * gsm_read_ea - read a byte into an EA
397 * @val: variable holding value
398 * c: byte going into the EA
400 * Processes one byte of an EA. Updates the passed variable
401 * and returns 1 if the EA is now completely read
404 static int gsm_read_ea(unsigned int *val, u8 c)
406 /* Add the next 7 bits into the value */
409 /* Was this the last byte of the EA 1 = yes*/
414 * gsm_read_ea_val - read a value until EA
415 * @val: variable holding value
416 * @data: buffer of data
417 * @dlen: length of data
419 * Processes an EA value. Updates the passed variable and
420 * returns the processed data length.
422 static unsigned int gsm_read_ea_val(unsigned int *val, const u8 *data, int dlen)
424 unsigned int len = 0;
426 for (; dlen > 0; dlen--) {
428 if (gsm_read_ea(val, *data++))
435 * gsm_encode_modem - encode modem data bits
436 * @dlci: DLCI to encode from
438 * Returns the correct GSM encoded modem status bits (6 bit field) for
439 * the current status of the DLCI and attached tty object
442 static u8 gsm_encode_modem(const struct gsm_dlci *dlci)
445 /* FC is true flow control not modem bits */
448 if (dlci->modem_tx & TIOCM_DTR)
449 modembits |= MDM_RTC;
450 if (dlci->modem_tx & TIOCM_RTS)
451 modembits |= MDM_RTR;
452 if (dlci->modem_tx & TIOCM_RI)
454 if (dlci->modem_tx & TIOCM_CD || dlci->gsm->initiator)
460 * gsm_print_packet - display a frame for debug
461 * @hdr: header to print before decode
462 * @addr: address EA from the frame
463 * @cr: C/R bit from the frame
464 * @control: control including PF bit
465 * @data: following data bytes
466 * @dlen: length of data
468 * Displays a packet in human readable format for debugging purposes. The
469 * style is based on amateur radio LAP-B dump display.
472 static void gsm_print_packet(const char *hdr, int addr, int cr,
473 u8 control, const u8 *data, int dlen)
478 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]);
480 switch (control & ~PF) {
500 if (!(control & 0x01)) {
501 pr_cont("I N(S)%d N(R)%d",
502 (control & 0x0E) >> 1, (control & 0xE0) >> 5);
503 } else switch (control & 0x0F) {
505 pr_cont("RR(%d)", (control & 0xE0) >> 5);
508 pr_cont("RNR(%d)", (control & 0xE0) >> 5);
511 pr_cont("REJ(%d)", (control & 0xE0) >> 5);
514 pr_cont("[%02X]", control);
530 pr_cont("%02X ", *data++);
539 * Link level transmission side
543 * gsm_stuff_packet - bytestuff a packet
546 * @len: length of input
548 * Expand a buffer by bytestuffing it. The worst case size change
549 * is doubling and the caller is responsible for handing out
550 * suitable sized buffers.
553 static int gsm_stuff_frame(const u8 *input, u8 *output, int len)
557 if (*input == GSM1_SOF || *input == GSM1_ESCAPE
558 || (*input & ISO_IEC_646_MASK) == XON
559 || (*input & ISO_IEC_646_MASK) == XOFF) {
560 *output++ = GSM1_ESCAPE;
561 *output++ = *input++ ^ GSM1_ESCAPE_BITS;
564 *output++ = *input++;
571 * gsm_send - send a control frame
573 * @addr: address for control frame
574 * @cr: command/response bit
575 * @control: control byte including PF bit
577 * Format up and transmit a control frame. These do not go via the
578 * queueing logic as they should be transmitted ahead of data when
581 * FIXME: Lock versus data TX path
584 static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control)
590 switch (gsm->encoding) {
593 cbuf[1] = (addr << 2) | (cr << 1) | EA;
595 cbuf[3] = EA; /* Length of data = 0 */
596 cbuf[4] = 0xFF - gsm_fcs_add_block(INIT_FCS, cbuf + 1, 3);
602 /* Control frame + packing (but not frame stuffing) in mode 1 */
603 ibuf[0] = (addr << 2) | (cr << 1) | EA;
605 ibuf[2] = 0xFF - gsm_fcs_add_block(INIT_FCS, ibuf, 2);
606 /* Stuffing may double the size worst case */
607 len = gsm_stuff_frame(ibuf, cbuf + 1, 3);
608 /* Now add the SOF markers */
610 cbuf[len + 1] = GSM1_SOF;
611 /* FIXME: we can omit the lead one in many cases */
618 gsm->output(gsm, cbuf, len);
619 gsm_print_packet("-->", addr, cr, control, NULL, 0);
623 * gsm_response - send a control response
625 * @addr: address for control frame
626 * @control: control byte including PF bit
628 * Format up and transmit a link level response frame.
631 static inline void gsm_response(struct gsm_mux *gsm, int addr, int control)
633 gsm_send(gsm, addr, 0, control);
637 * gsm_command - send a control command
639 * @addr: address for control frame
640 * @control: control byte including PF bit
642 * Format up and transmit a link level command frame.
645 static inline void gsm_command(struct gsm_mux *gsm, int addr, int control)
647 gsm_send(gsm, addr, 1, control);
650 /* Data transmission */
652 #define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */
655 * gsm_data_alloc - allocate data frame
657 * @addr: DLCI address
658 * @len: length excluding header and FCS
659 * @ctrl: control byte
661 * Allocate a new data buffer for sending frames with data. Space is left
662 * at the front for header bytes but that is treated as an implementation
663 * detail and not for the high level code to use
666 static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
669 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN,
673 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */
677 INIT_LIST_HEAD(&m->list);
682 * gsm_is_flow_ctrl_msg - checks if flow control message
683 * @msg: message to check
685 * Returns true if the given message is a flow control command of the
686 * control channel. False is returned in any other case.
688 static bool gsm_is_flow_ctrl_msg(struct gsm_msg *msg)
695 switch (msg->ctrl & ~PF) {
699 if (gsm_read_ea_val(&cmd, msg->data + 2, msg->len - 2) < 1)
713 * gsm_data_kick - poke the queue
716 * The tty device has called us to indicate that room has appeared in
717 * the transmit queue. Ram more data into the pipe if we have any
718 * If we have been flow-stopped by a CMD_FCOFF, then we can only
719 * send messages on DLCI0 until CMD_FCON
721 * FIXME: lock against link layer control transmissions
724 static void gsm_data_kick(struct gsm_mux *gsm, struct gsm_dlci *dlci)
726 struct gsm_msg *msg, *nmsg;
729 list_for_each_entry_safe(msg, nmsg, &gsm->tx_list, list) {
730 if (gsm->constipated && !gsm_is_flow_ctrl_msg(msg))
732 if (gsm->encoding != 0) {
733 gsm->txframe[0] = GSM1_SOF;
734 len = gsm_stuff_frame(msg->data,
735 gsm->txframe + 1, msg->len);
736 gsm->txframe[len + 1] = GSM1_SOF;
739 gsm->txframe[0] = GSM0_SOF;
740 memcpy(gsm->txframe + 1 , msg->data, msg->len);
741 gsm->txframe[msg->len + 1] = GSM0_SOF;
746 print_hex_dump_bytes("gsm_data_kick: ",
749 if (gsm->output(gsm, gsm->txframe, len) < 0)
751 /* FIXME: Can eliminate one SOF in many more cases */
752 gsm->tx_bytes -= msg->len;
754 list_del(&msg->list);
758 tty_port_tty_wakeup(&dlci->port);
762 for (i = 0; i < NUM_DLCI; i++)
764 tty_port_tty_wakeup(&gsm->dlci[i]->port);
770 * __gsm_data_queue - queue a UI or UIH frame
771 * @dlci: DLCI sending the data
772 * @msg: message queued
774 * Add data to the transmit queue and try and get stuff moving
775 * out of the mux tty if not already doing so. The Caller must hold
779 static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
781 struct gsm_mux *gsm = dlci->gsm;
783 u8 *fcs = dp + msg->len;
785 /* Fill in the header */
786 if (gsm->encoding == 0) {
788 *--dp = (msg->len << 1) | EA;
790 *--dp = (msg->len >> 7); /* bits 7 - 15 */
791 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */
797 *--dp = (msg->addr << 2) | 2 | EA;
799 *--dp = (msg->addr << 2) | EA;
800 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp);
801 /* Ugly protocol layering violation */
802 if (msg->ctrl == UI || msg->ctrl == (UI|PF))
803 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len);
806 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl,
807 msg->data, msg->len);
809 /* Move the header back and adjust the length, also allow for the FCS
810 now tacked on the end */
811 msg->len += (msg->data - dp) + 1;
814 /* Add to the actual output queue */
815 list_add_tail(&msg->list, &gsm->tx_list);
816 gsm->tx_bytes += msg->len;
817 gsm_data_kick(gsm, dlci);
821 * gsm_data_queue - queue a UI or UIH frame
822 * @dlci: DLCI sending the data
823 * @msg: message queued
825 * Add data to the transmit queue and try and get stuff moving
826 * out of the mux tty if not already doing so. Take the
827 * the gsm tx lock and dlci lock.
830 static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
833 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
834 __gsm_data_queue(dlci, msg);
835 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
839 * gsm_dlci_data_output - try and push data out of a DLCI
841 * @dlci: the DLCI to pull data from
843 * Pull data from a DLCI and send it into the transmit queue if there
844 * is data. Keep to the MRU of the mux. This path handles the usual tty
845 * interface which is a byte stream with optional modem data.
847 * Caller must hold the tx_lock of the mux.
850 static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci)
854 int len, total_size, size;
855 int h = dlci->adaption - 1;
859 len = kfifo_len(dlci->fifo);
863 /* MTU/MRU count only the data bits */
869 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
870 /* FIXME: need a timer or something to kick this so it can't
871 get stuck with no work outstanding and no buffer free */
875 switch (dlci->adaption) {
876 case 1: /* Unstructured */
878 case 2: /* Unstructed with modem bits.
879 Always one byte as we never send inline break data */
880 *dp++ = (gsm_encode_modem(dlci) << 1) | EA;
883 WARN_ON(kfifo_out_locked(dlci->fifo, dp , len, &dlci->lock) != len);
884 __gsm_data_queue(dlci, msg);
887 /* Bytes of data we used up */
892 * gsm_dlci_data_output_framed - try and push data out of a DLCI
894 * @dlci: the DLCI to pull data from
896 * Pull data from a DLCI and send it into the transmit queue if there
897 * is data. Keep to the MRU of the mux. This path handles framed data
898 * queued as skbuffs to the DLCI.
900 * Caller must hold the tx_lock of the mux.
903 static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
904 struct gsm_dlci *dlci)
909 int last = 0, first = 0;
912 /* One byte per frame is used for B/F flags */
913 if (dlci->adaption == 4)
916 /* dlci->skb is locked by tx_lock */
917 if (dlci->skb == NULL) {
918 dlci->skb = skb_dequeue_tail(&dlci->skb_list);
919 if (dlci->skb == NULL)
923 len = dlci->skb->len + overhead;
925 /* MTU/MRU count only the data bits */
926 if (len > gsm->mtu) {
927 if (dlci->adaption == 3) {
928 /* Over long frame, bin it */
929 dev_kfree_skb_any(dlci->skb);
937 size = len + overhead;
938 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
940 /* FIXME: need a timer or something to kick this so it can't
941 get stuck with no work outstanding and no buffer free */
943 skb_queue_tail(&dlci->skb_list, dlci->skb);
949 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */
950 /* Flag byte to carry the start/end info */
951 *dp++ = last << 7 | first << 6 | 1; /* EA */
954 memcpy(dp, dlci->skb->data, len);
955 skb_pull(dlci->skb, len);
956 __gsm_data_queue(dlci, msg);
958 dev_kfree_skb_any(dlci->skb);
965 * gsm_dlci_data_sweep - look for data to send
968 * Sweep the GSM mux channels in priority order looking for ones with
969 * data to send. We could do with optimising this scan a bit. We aim
970 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit
971 * TX_THRESH_LO we get called again
973 * FIXME: We should round robin between groups and in theory you can
974 * renegotiate DLCI priorities with optional stuff. Needs optimising.
977 static void gsm_dlci_data_sweep(struct gsm_mux *gsm)
980 /* Priority ordering: We should do priority with RR of the groups */
983 while (i < NUM_DLCI) {
984 struct gsm_dlci *dlci;
986 if (gsm->tx_bytes > TX_THRESH_HI)
989 if (dlci == NULL || dlci->constipated) {
993 if (dlci->adaption < 3 && !dlci->net)
994 len = gsm_dlci_data_output(gsm, dlci);
996 len = gsm_dlci_data_output_framed(gsm, dlci);
999 /* DLCI empty - try the next */
1006 * gsm_dlci_data_kick - transmit if possible
1007 * @dlci: DLCI to kick
1009 * Transmit data from this DLCI if the queue is empty. We can't rely on
1010 * a tty wakeup except when we filled the pipe so we need to fire off
1011 * new data ourselves in other cases.
1014 static void gsm_dlci_data_kick(struct gsm_dlci *dlci)
1016 unsigned long flags;
1019 if (dlci->constipated)
1022 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
1023 /* If we have nothing running then we need to fire up */
1024 sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO);
1025 if (dlci->gsm->tx_bytes == 0) {
1027 gsm_dlci_data_output_framed(dlci->gsm, dlci);
1029 gsm_dlci_data_output(dlci->gsm, dlci);
1032 gsm_dlci_data_sweep(dlci->gsm);
1033 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
1037 * Control message processing
1042 * gsm_control_reply - send a response frame to a control
1044 * @cmd: the command to use
1045 * @data: data to follow encoded info
1046 * @dlen: length of data
1048 * Encode up and queue a UI/UIH frame containing our response.
1051 static void gsm_control_reply(struct gsm_mux *gsm, int cmd, u8 *data,
1054 struct gsm_msg *msg;
1055 msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype);
1058 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */
1059 msg->data[1] = (dlen << 1) | EA;
1060 memcpy(msg->data + 2, data, dlen);
1061 gsm_data_queue(gsm->dlci[0], msg);
1065 * gsm_process_modem - process received modem status
1066 * @tty: virtual tty bound to the DLCI
1067 * @dlci: DLCI to affect
1068 * @modem: modem bits (full EA)
1070 * Used when a modem control message or line state inline in adaption
1071 * layer 2 is processed. Sort out the local modem state and throttles
1074 static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
1075 u32 modem, int clen)
1081 /* The modem status command can either contain one octet (v.24 signals)
1082 or two octets (v.24 signals + break signals). The length field will
1083 either be 2 or 3 respectively. This is specified in section
1084 5.4.6.3.7 of the 27.010 mux spec. */
1087 modem = modem & 0x7f;
1090 modem = (modem >> 7) & 0x7f;
1093 /* Flow control/ready to communicate */
1094 fc = (modem & MDM_FC) || !(modem & MDM_RTR);
1095 if (fc && !dlci->constipated) {
1096 /* Need to throttle our output on this device */
1097 dlci->constipated = 1;
1098 } else if (!fc && dlci->constipated) {
1099 dlci->constipated = 0;
1100 gsm_dlci_data_kick(dlci);
1103 /* Map modem bits */
1104 if (modem & MDM_RTC)
1105 mlines |= TIOCM_DSR | TIOCM_DTR;
1106 if (modem & MDM_RTR)
1107 mlines |= TIOCM_RTS | TIOCM_CTS;
1113 /* Carrier drop -> hangup */
1115 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD))
1120 tty_insert_flip_char(&dlci->port, 0, TTY_BREAK);
1121 dlci->modem_rx = mlines;
1125 * gsm_control_modem - modem status received
1127 * @data: data following command
1128 * @clen: command length
1130 * We have received a modem status control message. This is used by
1131 * the GSM mux protocol to pass virtual modem line status and optionally
1132 * to indicate break signals. Unpack it, convert to Linux representation
1133 * and if need be stuff a break message down the tty.
1136 static void gsm_control_modem(struct gsm_mux *gsm, u8 *data, int clen)
1138 unsigned int addr = 0;
1139 unsigned int modem = 0;
1140 unsigned int brk = 0;
1141 struct gsm_dlci *dlci;
1144 struct tty_struct *tty;
1146 while (gsm_read_ea(&addr, *dp++) == 0) {
1151 /* Must be at least one byte following the EA */
1157 /* Closed port, or invalid ? */
1158 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1160 dlci = gsm->dlci[addr];
1162 while (gsm_read_ea(&modem, *dp++) == 0) {
1169 while (gsm_read_ea(&brk, *dp++) == 0) {
1175 modem |= (brk & 0x7f);
1177 tty = tty_port_tty_get(&dlci->port);
1178 gsm_process_modem(tty, dlci, modem, clen);
1183 gsm_control_reply(gsm, CMD_MSC, data, clen);
1187 * gsm_control_rls - remote line status
1190 * @clen: data length
1192 * The modem sends us a two byte message on the control channel whenever
1193 * it wishes to send us an error state from the virtual link. Stuff
1194 * this into the uplink tty if present
1197 static void gsm_control_rls(struct gsm_mux *gsm, u8 *data, int clen)
1199 struct tty_port *port;
1200 unsigned int addr = 0;
1205 while (gsm_read_ea(&addr, *dp++) == 0) {
1210 /* Must be at least one byte following ea */
1215 /* Closed port, or invalid ? */
1216 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1220 if ((bits & 1) == 0)
1223 port = &gsm->dlci[addr]->port;
1226 tty_insert_flip_char(port, 0, TTY_OVERRUN);
1228 tty_insert_flip_char(port, 0, TTY_PARITY);
1230 tty_insert_flip_char(port, 0, TTY_FRAME);
1232 tty_flip_buffer_push(port);
1234 gsm_control_reply(gsm, CMD_RLS, data, clen);
1237 static void gsm_dlci_begin_close(struct gsm_dlci *dlci);
1240 * gsm_control_message - DLCI 0 control processing
1242 * @command: the command EA
1243 * @data: data beyond the command/length EAs
1246 * Input processor for control messages from the other end of the link.
1247 * Processes the incoming request and queues a response frame or an
1248 * NSC response if not supported
1251 static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
1255 unsigned long flags;
1259 struct gsm_dlci *dlci = gsm->dlci[0];
1260 /* Modem wishes to close down */
1264 gsm_dlci_begin_close(dlci);
1269 /* Modem wishes to test, reply with the data */
1270 gsm_control_reply(gsm, CMD_TEST, data, clen);
1273 /* Modem can accept data again */
1274 gsm->constipated = 0;
1275 gsm_control_reply(gsm, CMD_FCON, NULL, 0);
1276 /* Kick the link in case it is idling */
1277 spin_lock_irqsave(&gsm->tx_lock, flags);
1278 gsm_data_kick(gsm, NULL);
1279 spin_unlock_irqrestore(&gsm->tx_lock, flags);
1282 /* Modem wants us to STFU */
1283 gsm->constipated = 1;
1284 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0);
1287 /* Out of band modem line change indicator for a DLCI */
1288 gsm_control_modem(gsm, data, clen);
1291 /* Out of band error reception for a DLCI */
1292 gsm_control_rls(gsm, data, clen);
1295 /* Modem wishes to enter power saving state */
1296 gsm_control_reply(gsm, CMD_PSC, NULL, 0);
1298 /* Optional unsupported commands */
1299 case CMD_PN: /* Parameter negotiation */
1300 case CMD_RPN: /* Remote port negotiation */
1301 case CMD_SNC: /* Service negotiation command */
1303 /* Reply to bad commands with an NSC */
1305 gsm_control_reply(gsm, CMD_NSC, buf, 1);
1311 * gsm_control_response - process a response to our control
1313 * @command: the command (response) EA
1314 * @data: data beyond the command/length EA
1317 * Process a response to an outstanding command. We only allow a single
1318 * control message in flight so this is fairly easy. All the clean up
1319 * is done by the caller, we just update the fields, flag it as done
1323 static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
1326 struct gsm_control *ctrl;
1327 unsigned long flags;
1329 spin_lock_irqsave(&gsm->control_lock, flags);
1331 ctrl = gsm->pending_cmd;
1332 /* Does the reply match our command */
1334 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) {
1335 /* Our command was replied to, kill the retry timer */
1336 del_timer(&gsm->t2_timer);
1337 gsm->pending_cmd = NULL;
1338 /* Rejected by the other end */
1339 if (command == CMD_NSC)
1340 ctrl->error = -EOPNOTSUPP;
1342 wake_up(&gsm->event);
1344 spin_unlock_irqrestore(&gsm->control_lock, flags);
1348 * gsm_control_transmit - send control packet
1350 * @ctrl: frame to send
1352 * Send out a pending control command (called under control lock)
1355 static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl)
1357 struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 2, gsm->ftype);
1360 msg->data[0] = (ctrl->cmd << 1) | CR | EA; /* command */
1361 msg->data[1] = (ctrl->len << 1) | EA;
1362 memcpy(msg->data + 2, ctrl->data, ctrl->len);
1363 gsm_data_queue(gsm->dlci[0], msg);
1367 * gsm_control_retransmit - retransmit a control frame
1368 * @data: pointer to our gsm object
1370 * Called off the T2 timer expiry in order to retransmit control frames
1371 * that have been lost in the system somewhere. The control_lock protects
1372 * us from colliding with another sender or a receive completion event.
1373 * In that situation the timer may still occur in a small window but
1374 * gsm->pending_cmd will be NULL and we just let the timer expire.
1377 static void gsm_control_retransmit(struct timer_list *t)
1379 struct gsm_mux *gsm = from_timer(gsm, t, t2_timer);
1380 struct gsm_control *ctrl;
1381 unsigned long flags;
1382 spin_lock_irqsave(&gsm->control_lock, flags);
1383 ctrl = gsm->pending_cmd;
1385 if (gsm->cretries == 0 || !gsm->dlci[0] || gsm->dlci[0]->dead) {
1386 gsm->pending_cmd = NULL;
1387 ctrl->error = -ETIMEDOUT;
1389 spin_unlock_irqrestore(&gsm->control_lock, flags);
1390 wake_up(&gsm->event);
1394 gsm_control_transmit(gsm, ctrl);
1395 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1397 spin_unlock_irqrestore(&gsm->control_lock, flags);
1401 * gsm_control_send - send a control frame on DLCI 0
1402 * @gsm: the GSM channel
1403 * @command: command to send including CR bit
1404 * @data: bytes of data (must be kmalloced)
1405 * @len: length of the block to send
1407 * Queue and dispatch a control command. Only one command can be
1408 * active at a time. In theory more can be outstanding but the matching
1409 * gets really complicated so for now stick to one outstanding.
1412 static struct gsm_control *gsm_control_send(struct gsm_mux *gsm,
1413 unsigned int command, u8 *data, int clen)
1415 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control),
1417 unsigned long flags;
1421 wait_event(gsm->event, gsm->pending_cmd == NULL);
1422 spin_lock_irqsave(&gsm->control_lock, flags);
1423 if (gsm->pending_cmd != NULL) {
1424 spin_unlock_irqrestore(&gsm->control_lock, flags);
1427 ctrl->cmd = command;
1430 gsm->pending_cmd = ctrl;
1432 /* If DLCI0 is in ADM mode skip retries, it won't respond */
1433 if (gsm->dlci[0]->mode == DLCI_MODE_ADM)
1436 gsm->cretries = gsm->n2;
1438 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1439 gsm_control_transmit(gsm, ctrl);
1440 spin_unlock_irqrestore(&gsm->control_lock, flags);
1445 * gsm_control_wait - wait for a control to finish
1447 * @control: control we are waiting on
1449 * Waits for the control to complete or time out. Frees any used
1450 * resources and returns 0 for success, or an error if the remote
1451 * rejected or ignored the request.
1454 static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
1457 wait_event(gsm->event, control->done == 1);
1458 err = control->error;
1465 * DLCI level handling: Needs krefs
1469 * State transitions and timers
1473 * gsm_dlci_close - a DLCI has closed
1474 * @dlci: DLCI that closed
1476 * Perform processing when moving a DLCI into closed state. If there
1477 * is an attached tty this is hung up
1480 static void gsm_dlci_close(struct gsm_dlci *dlci)
1482 del_timer(&dlci->t1);
1484 pr_debug("DLCI %d goes closed.\n", dlci->addr);
1485 dlci->state = DLCI_CLOSED;
1486 if (dlci->addr != 0) {
1487 tty_port_tty_hangup(&dlci->port, false);
1488 kfifo_reset(dlci->fifo);
1490 dlci->gsm->dead = 1;
1491 wake_up(&dlci->gsm->event);
1492 /* A DLCI 0 close is a MUX termination so we need to kick that
1493 back to userspace somehow */
1497 * gsm_dlci_open - a DLCI has opened
1498 * @dlci: DLCI that opened
1500 * Perform processing when moving a DLCI into open state.
1503 static void gsm_dlci_open(struct gsm_dlci *dlci)
1505 /* Note that SABM UA .. SABM UA first UA lost can mean that we go
1507 del_timer(&dlci->t1);
1508 /* This will let a tty open continue */
1509 dlci->state = DLCI_OPEN;
1511 pr_debug("DLCI %d goes open.\n", dlci->addr);
1512 wake_up(&dlci->gsm->event);
1516 * gsm_dlci_t1 - T1 timer expiry
1517 * @dlci: DLCI that opened
1519 * The T1 timer handles retransmits of control frames (essentially of
1520 * SABM and DISC). We resend the command until the retry count runs out
1521 * in which case an opening port goes back to closed and a closing port
1522 * is simply put into closed state (any further frames from the other
1523 * end will get a DM response)
1525 * Some control dlci can stay in ADM mode with other dlci working just
1526 * fine. In that case we can just keep the control dlci open after the
1527 * DLCI_OPENING retries time out.
1530 static void gsm_dlci_t1(struct timer_list *t)
1532 struct gsm_dlci *dlci = from_timer(dlci, t, t1);
1533 struct gsm_mux *gsm = dlci->gsm;
1535 switch (dlci->state) {
1537 if (dlci->retries) {
1539 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1540 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1541 } else if (!dlci->addr && gsm->control == (DM | PF)) {
1543 pr_info("DLCI %d opening in ADM mode.\n",
1545 dlci->mode = DLCI_MODE_ADM;
1546 gsm_dlci_open(dlci);
1548 gsm_dlci_begin_close(dlci); /* prevent half open link */
1553 if (dlci->retries) {
1555 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1556 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1558 gsm_dlci_close(dlci);
1564 * gsm_dlci_begin_open - start channel open procedure
1565 * @dlci: DLCI to open
1567 * Commence opening a DLCI from the Linux side. We issue SABM messages
1568 * to the modem which should then reply with a UA or ADM, at which point
1569 * we will move into open state. Opening is done asynchronously with retry
1570 * running off timers and the responses.
1573 static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
1575 struct gsm_mux *gsm = dlci->gsm;
1576 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING)
1578 dlci->retries = gsm->n2;
1579 dlci->state = DLCI_OPENING;
1580 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1581 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1585 * gsm_dlci_begin_close - start channel open procedure
1586 * @dlci: DLCI to open
1588 * Commence closing a DLCI from the Linux side. We issue DISC messages
1589 * to the modem which should then reply with a UA, at which point we
1590 * will move into closed state. Closing is done asynchronously with retry
1591 * off timers. We may also receive a DM reply from the other end which
1592 * indicates the channel was already closed.
1595 static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
1597 struct gsm_mux *gsm = dlci->gsm;
1598 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
1600 dlci->retries = gsm->n2;
1601 dlci->state = DLCI_CLOSING;
1602 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1603 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1607 * gsm_dlci_data - data arrived
1609 * @data: block of bytes received
1610 * @len: length of received block
1612 * A UI or UIH frame has arrived which contains data for a channel
1613 * other than the control channel. If the relevant virtual tty is
1614 * open we shovel the bits down it, if not we drop them.
1617 static void gsm_dlci_data(struct gsm_dlci *dlci, u8 *data, int clen)
1620 struct tty_port *port = &dlci->port;
1621 struct tty_struct *tty;
1622 unsigned int modem = 0;
1626 pr_debug("%d bytes for tty\n", len);
1627 switch (dlci->adaption) {
1628 /* Unsupported types */
1629 /* Packetised interruptible data */
1632 /* Packetised uininterruptible voice/data */
1635 /* Asynchronous serial with line state in each frame */
1637 while (gsm_read_ea(&modem, *data++) == 0) {
1642 tty = tty_port_tty_get(port);
1644 gsm_process_modem(tty, dlci, modem, clen);
1647 /* Line state will go via DLCI 0 controls only */
1650 tty_insert_flip_string(port, data, len);
1651 tty_flip_buffer_push(port);
1656 * gsm_dlci_control - data arrived on control channel
1658 * @data: block of bytes received
1659 * @len: length of received block
1661 * A UI or UIH frame has arrived which contains data for DLCI 0 the
1662 * control channel. This should contain a command EA followed by
1663 * control data bytes. The command EA contains a command/response bit
1664 * and we divide up the work accordingly.
1667 static void gsm_dlci_command(struct gsm_dlci *dlci, u8 *data, int len)
1669 /* See what command is involved */
1670 unsigned int command = 0;
1672 if (gsm_read_ea(&command, *data++) == 1) {
1675 /* FIXME: this is properly an EA */
1677 /* Malformed command ? */
1681 gsm_control_message(dlci->gsm, command,
1684 gsm_control_response(dlci->gsm, command,
1692 * Allocate/Free DLCI channels
1696 * gsm_dlci_alloc - allocate a DLCI
1698 * @addr: address of the DLCI
1700 * Allocate and install a new DLCI object into the GSM mux.
1702 * FIXME: review locking races
1705 static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
1707 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC);
1710 spin_lock_init(&dlci->lock);
1711 mutex_init(&dlci->mutex);
1712 dlci->fifo = &dlci->_fifo;
1713 if (kfifo_alloc(&dlci->_fifo, 4096, GFP_KERNEL) < 0) {
1718 skb_queue_head_init(&dlci->skb_list);
1719 timer_setup(&dlci->t1, gsm_dlci_t1, 0);
1720 tty_port_init(&dlci->port);
1721 dlci->port.ops = &gsm_port_ops;
1724 dlci->adaption = gsm->adaption;
1725 dlci->state = DLCI_CLOSED;
1727 dlci->data = gsm_dlci_data;
1729 dlci->data = gsm_dlci_command;
1730 gsm->dlci[addr] = dlci;
1735 * gsm_dlci_free - free DLCI
1736 * @dlci: DLCI to free
1742 static void gsm_dlci_free(struct tty_port *port)
1744 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
1746 del_timer_sync(&dlci->t1);
1747 dlci->gsm->dlci[dlci->addr] = NULL;
1748 kfifo_free(dlci->fifo);
1749 while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
1750 dev_kfree_skb(dlci->skb);
1754 static inline void dlci_get(struct gsm_dlci *dlci)
1756 tty_port_get(&dlci->port);
1759 static inline void dlci_put(struct gsm_dlci *dlci)
1761 tty_port_put(&dlci->port);
1764 static void gsm_destroy_network(struct gsm_dlci *dlci);
1767 * gsm_dlci_release - release DLCI
1768 * @dlci: DLCI to destroy
1770 * Release a DLCI. Actual free is deferred until either
1771 * mux is closed or tty is closed - whichever is last.
1775 static void gsm_dlci_release(struct gsm_dlci *dlci)
1777 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1779 mutex_lock(&dlci->mutex);
1780 gsm_destroy_network(dlci);
1781 mutex_unlock(&dlci->mutex);
1785 tty_port_tty_set(&dlci->port, NULL);
1788 dlci->state = DLCI_CLOSED;
1793 * LAPBish link layer logic
1797 * gsm_queue - a GSM frame is ready to process
1798 * @gsm: pointer to our gsm mux
1800 * At this point in time a frame has arrived and been demangled from
1801 * the line encoding. All the differences between the encodings have
1802 * been handled below us and the frame is unpacked into the structures.
1803 * The fcs holds the header FCS but any data FCS must be added here.
1806 static void gsm_queue(struct gsm_mux *gsm)
1808 struct gsm_dlci *dlci;
1811 /* We have to sneak a look at the packet body to do the FCS.
1812 A somewhat layering violation in the spec */
1814 if ((gsm->control & ~PF) == UI)
1815 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len);
1816 if (gsm->encoding == 0) {
1817 /* WARNING: gsm->received_fcs is used for
1818 gsm->encoding = 0 only.
1819 In this case it contain the last piece of data
1820 required to generate final CRC */
1821 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs);
1823 if (gsm->fcs != GOOD_FCS) {
1826 pr_debug("BAD FCS %02x\n", gsm->fcs);
1829 address = gsm->address >> 1;
1830 if (address >= NUM_DLCI)
1833 cr = gsm->address & 1; /* C/R bit */
1835 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
1837 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */
1838 dlci = gsm->dlci[address];
1840 switch (gsm->control) {
1845 dlci = gsm_dlci_alloc(gsm, address);
1849 gsm_response(gsm, address, DM);
1851 gsm_response(gsm, address, UA);
1852 gsm_dlci_open(dlci);
1858 if (dlci == NULL || dlci->state == DLCI_CLOSED) {
1859 gsm_response(gsm, address, DM);
1862 /* Real close complete */
1863 gsm_response(gsm, address, UA);
1864 gsm_dlci_close(dlci);
1867 if (cr == 0 || dlci == NULL)
1869 switch (dlci->state) {
1871 gsm_dlci_close(dlci);
1874 gsm_dlci_open(dlci);
1878 case DM: /* DM can be valid unsolicited */
1884 gsm_dlci_close(dlci);
1894 if (dlci == NULL || dlci->state != DLCI_OPEN) {
1895 gsm_response(gsm, address, DM|PF);
1898 dlci->data(dlci, gsm->buf, gsm->len);
1911 * gsm0_receive - perform processing for non-transparency
1912 * @gsm: gsm data for this ldisc instance
1915 * Receive bytes in gsm mode 0
1918 static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
1922 switch (gsm->state) {
1923 case GSM_SEARCH: /* SOF marker */
1924 if (c == GSM0_SOF) {
1925 gsm->state = GSM_ADDRESS;
1928 gsm->fcs = INIT_FCS;
1931 case GSM_ADDRESS: /* Address EA */
1932 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1933 if (gsm_read_ea(&gsm->address, c))
1934 gsm->state = GSM_CONTROL;
1936 case GSM_CONTROL: /* Control Byte */
1937 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1939 gsm->state = GSM_LEN0;
1941 case GSM_LEN0: /* Length EA */
1942 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1943 if (gsm_read_ea(&gsm->len, c)) {
1944 if (gsm->len > gsm->mru) {
1946 gsm->state = GSM_SEARCH;
1951 gsm->state = GSM_FCS;
1953 gsm->state = GSM_DATA;
1956 gsm->state = GSM_LEN1;
1959 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1961 gsm->len |= len << 7;
1962 if (gsm->len > gsm->mru) {
1964 gsm->state = GSM_SEARCH;
1969 gsm->state = GSM_FCS;
1971 gsm->state = GSM_DATA;
1973 case GSM_DATA: /* Data */
1974 gsm->buf[gsm->count++] = c;
1975 if (gsm->count == gsm->len)
1976 gsm->state = GSM_FCS;
1978 case GSM_FCS: /* FCS follows the packet */
1979 gsm->received_fcs = c;
1981 gsm->state = GSM_SSOF;
1984 if (c == GSM0_SOF) {
1985 gsm->state = GSM_SEARCH;
1993 * gsm1_receive - perform processing for non-transparency
1994 * @gsm: gsm data for this ldisc instance
1997 * Receive bytes in mode 1 (Advanced option)
2000 static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
2002 if (c == GSM1_SOF) {
2003 /* EOF is only valid in frame if we have got to the data state
2004 and received at least one byte (the FCS) */
2005 if (gsm->state == GSM_DATA && gsm->count) {
2006 /* Extract the FCS */
2008 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
2009 gsm->len = gsm->count;
2011 gsm->state = GSM_START;
2014 /* Any partial frame was a runt so go back to start */
2015 if (gsm->state != GSM_START) {
2016 if (gsm->state != GSM_SEARCH)
2018 gsm->state = GSM_START;
2020 /* A SOF in GSM_START means we are still reading idling or
2025 if (c == GSM1_ESCAPE) {
2030 /* Only an unescaped SOF gets us out of GSM search */
2031 if (gsm->state == GSM_SEARCH)
2035 c ^= GSM1_ESCAPE_BITS;
2038 switch (gsm->state) {
2039 case GSM_START: /* First byte after SOF */
2041 gsm->state = GSM_ADDRESS;
2042 gsm->fcs = INIT_FCS;
2044 case GSM_ADDRESS: /* Address continuation */
2045 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2046 if (gsm_read_ea(&gsm->address, c))
2047 gsm->state = GSM_CONTROL;
2049 case GSM_CONTROL: /* Control Byte */
2050 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2053 gsm->state = GSM_DATA;
2055 case GSM_DATA: /* Data */
2056 if (gsm->count > gsm->mru) { /* Allow one for the FCS */
2057 gsm->state = GSM_OVERRUN;
2060 gsm->buf[gsm->count++] = c;
2062 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */
2068 * gsm_error - handle tty error
2070 * @data: byte received (may be invalid)
2071 * @flag: error received
2073 * Handle an error in the receipt of data for a frame. Currently we just
2074 * go back to hunting for a SOF.
2076 * FIXME: better diagnostics ?
2079 static void gsm_error(struct gsm_mux *gsm,
2080 unsigned char data, unsigned char flag)
2082 gsm->state = GSM_SEARCH;
2086 static int gsm_disconnect(struct gsm_mux *gsm)
2088 struct gsm_dlci *dlci = gsm->dlci[0];
2089 struct gsm_control *gc;
2094 /* In theory disconnecting DLCI 0 is sufficient but for some
2095 modems this is apparently not the case. */
2096 gc = gsm_control_send(gsm, CMD_CLD, NULL, 0);
2098 gsm_control_wait(gsm, gc);
2100 del_timer_sync(&gsm->t2_timer);
2101 /* Now we are sure T2 has stopped */
2103 gsm_dlci_begin_close(dlci);
2104 wait_event_interruptible(gsm->event,
2105 dlci->state == DLCI_CLOSED);
2107 if (signal_pending(current))
2114 * gsm_cleanup_mux - generic GSM protocol cleanup
2117 * Clean up the bits of the mux which are the same for all framing
2118 * protocols. Remove the mux from the mux table, stop all the timers
2119 * and then shut down each device hanging up the channels as we go.
2122 static void gsm_cleanup_mux(struct gsm_mux *gsm)
2125 struct gsm_dlci *dlci = gsm->dlci[0];
2126 struct gsm_msg *txq, *ntxq;
2130 spin_lock(&gsm_mux_lock);
2131 for (i = 0; i < MAX_MUX; i++) {
2132 if (gsm_mux[i] == gsm) {
2137 spin_unlock(&gsm_mux_lock);
2138 /* open failed before registering => nothing to do */
2142 del_timer_sync(&gsm->t2_timer);
2143 /* Now we are sure T2 has stopped */
2147 /* Free up any link layer users */
2148 mutex_lock(&gsm->mutex);
2149 for (i = 0; i < NUM_DLCI; i++)
2151 gsm_dlci_release(gsm->dlci[i]);
2152 mutex_unlock(&gsm->mutex);
2153 /* Now wipe the queues */
2154 tty_ldisc_flush(gsm->tty);
2155 list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list)
2157 INIT_LIST_HEAD(&gsm->tx_list);
2161 * gsm_activate_mux - generic GSM setup
2164 * Set up the bits of the mux which are the same for all framing
2165 * protocols. Add the mux to the mux table so it can be opened and
2166 * finally kick off connecting to DLCI 0 on the modem.
2169 static int gsm_activate_mux(struct gsm_mux *gsm)
2171 struct gsm_dlci *dlci;
2174 timer_setup(&gsm->t2_timer, gsm_control_retransmit, 0);
2175 init_waitqueue_head(&gsm->event);
2176 spin_lock_init(&gsm->control_lock);
2177 spin_lock_init(&gsm->tx_lock);
2179 if (gsm->encoding == 0)
2180 gsm->receive = gsm0_receive;
2182 gsm->receive = gsm1_receive;
2183 gsm->error = gsm_error;
2185 spin_lock(&gsm_mux_lock);
2186 for (i = 0; i < MAX_MUX; i++) {
2187 if (gsm_mux[i] == NULL) {
2193 spin_unlock(&gsm_mux_lock);
2197 dlci = gsm_dlci_alloc(gsm, 0);
2200 gsm->dead = 0; /* Tty opens are now permissible */
2205 * gsm_free_mux - free up a mux
2208 * Dispose of allocated resources for a dead mux
2210 static void gsm_free_mux(struct gsm_mux *gsm)
2212 kfree(gsm->txframe);
2218 * gsm_free_muxr - free up a mux
2221 * Dispose of allocated resources for a dead mux
2223 static void gsm_free_muxr(struct kref *ref)
2225 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref);
2229 static inline void mux_get(struct gsm_mux *gsm)
2231 kref_get(&gsm->ref);
2234 static inline void mux_put(struct gsm_mux *gsm)
2236 kref_put(&gsm->ref, gsm_free_muxr);
2240 * gsm_alloc_mux - allocate a mux
2242 * Creates a new mux ready for activation.
2245 static struct gsm_mux *gsm_alloc_mux(void)
2247 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
2250 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL);
2251 if (gsm->buf == NULL) {
2255 gsm->txframe = kmalloc(2 * (MAX_MTU + PROT_OVERHEAD - 1), GFP_KERNEL);
2256 if (gsm->txframe == NULL) {
2261 spin_lock_init(&gsm->lock);
2262 mutex_init(&gsm->mutex);
2263 kref_init(&gsm->ref);
2264 INIT_LIST_HEAD(&gsm->tx_list);
2272 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
2274 gsm->dead = 1; /* Avoid early tty opens */
2280 * gsmld_output - write to link
2282 * @data: bytes to output
2285 * Write a block of data from the GSM mux to the data channel. This
2286 * will eventually be serialized from above but at the moment isn't.
2289 static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
2291 if (tty_write_room(gsm->tty) < len) {
2292 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
2296 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET,
2298 gsm->tty->ops->write(gsm->tty, data, len);
2303 * gsmld_attach_gsm - mode set up
2304 * @tty: our tty structure
2307 * Set up the MUX for basic mode and commence connecting to the
2308 * modem. Currently called from the line discipline set up but
2309 * will need moving to an ioctl path.
2312 static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2316 gsm->tty = tty_kref_get(tty);
2317 gsm->output = gsmld_output;
2318 ret = gsm_activate_mux(gsm);
2320 tty_kref_put(gsm->tty);
2322 /* Don't register device 0 - this is the control channel and not
2323 a usable tty interface */
2324 base = gsm->num << 6; /* Base for this MUX */
2325 for (i = 1; i < NUM_DLCI; i++)
2326 tty_register_device(gsm_tty_driver, base + i, NULL);
2333 * gsmld_detach_gsm - stop doing 0710 mux
2334 * @tty: tty attached to the mux
2337 * Shutdown and then clean up the resources used by the line discipline
2340 static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2343 int base = gsm->num << 6; /* Base for this MUX */
2345 WARN_ON(tty != gsm->tty);
2346 for (i = 1; i < NUM_DLCI; i++)
2347 tty_unregister_device(gsm_tty_driver, base + i);
2348 gsm_cleanup_mux(gsm);
2349 tty_kref_put(gsm->tty);
2353 static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
2354 char *fp, int count)
2356 struct gsm_mux *gsm = tty->disc_data;
2357 const unsigned char *dp;
2360 char flags = TTY_NORMAL;
2363 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET,
2366 for (i = count, dp = cp, f = fp; i; i--, dp++) {
2371 gsm->receive(gsm, *dp);
2377 gsm->error(gsm, *dp, flags);
2380 WARN_ONCE(1, "%s: unknown flag %d\n",
2381 tty_name(tty), flags);
2385 /* FASYNC if needed ? */
2386 /* If clogged call tty_throttle(tty); */
2390 * gsmld_flush_buffer - clean input queue
2391 * @tty: terminal device
2393 * Flush the input buffer. Called when the line discipline is
2394 * being closed, when the tty layer wants the buffer flushed (eg
2398 static void gsmld_flush_buffer(struct tty_struct *tty)
2403 * gsmld_close - close the ldisc for this tty
2406 * Called from the terminal layer when this line discipline is
2407 * being shut down, either because of a close or becsuse of a
2408 * discipline change. The function will not be called while other
2409 * ldisc methods are in progress.
2412 static void gsmld_close(struct tty_struct *tty)
2414 struct gsm_mux *gsm = tty->disc_data;
2416 gsmld_detach_gsm(tty, gsm);
2418 gsmld_flush_buffer(tty);
2419 /* Do other clean up here */
2424 * gsmld_open - open an ldisc
2425 * @tty: terminal to open
2427 * Called when this line discipline is being attached to the
2428 * terminal device. Can sleep. Called serialized so that no
2429 * other events will occur in parallel. No further open will occur
2433 static int gsmld_open(struct tty_struct *tty)
2435 struct gsm_mux *gsm;
2438 if (!capable(CAP_NET_ADMIN))
2441 if (tty->ops->write == NULL)
2444 /* Attach our ldisc data */
2445 gsm = gsm_alloc_mux();
2449 tty->disc_data = gsm;
2450 tty->receive_room = 65536;
2452 /* Attach the initial passive connection */
2455 ret = gsmld_attach_gsm(tty, gsm);
2457 gsm_cleanup_mux(gsm);
2464 * gsmld_write_wakeup - asynchronous I/O notifier
2467 * Required for the ptys, serial driver etc. since processes
2468 * that attach themselves to the master and rely on ASYNC
2469 * IO must be woken up
2472 static void gsmld_write_wakeup(struct tty_struct *tty)
2474 struct gsm_mux *gsm = tty->disc_data;
2475 unsigned long flags;
2478 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2479 spin_lock_irqsave(&gsm->tx_lock, flags);
2480 gsm_data_kick(gsm, NULL);
2481 if (gsm->tx_bytes < TX_THRESH_LO) {
2482 gsm_dlci_data_sweep(gsm);
2484 spin_unlock_irqrestore(&gsm->tx_lock, flags);
2488 * gsmld_read - read function for tty
2490 * @file: file object
2491 * @buf: userspace buffer pointer
2494 * Perform reads for the line discipline. We are guaranteed that the
2495 * line discipline will not be closed under us but we may get multiple
2496 * parallel readers and must handle this ourselves. We may also get
2497 * a hangup. Always called in user context, may sleep.
2499 * This code must be sure never to sleep through a hangup.
2502 static ssize_t gsmld_read(struct tty_struct *tty, struct file *file,
2503 unsigned char __user *buf, size_t nr)
2509 * gsmld_write - write function for tty
2511 * @file: file object
2512 * @buf: userspace buffer pointer
2515 * Called when the owner of the device wants to send a frame
2516 * itself (or some other control data). The data is transferred
2517 * as-is and must be properly framed and checksummed as appropriate
2518 * by userspace. Frames are either sent whole or not at all as this
2519 * avoids pain user side.
2522 static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
2523 const unsigned char *buf, size_t nr)
2525 struct gsm_mux *gsm = tty->disc_data;
2526 unsigned long flags;
2534 spin_lock_irqsave(&gsm->tx_lock, flags);
2535 space = tty_write_room(tty);
2537 ret = tty->ops->write(tty, buf, nr);
2539 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2540 spin_unlock_irqrestore(&gsm->tx_lock, flags);
2546 * gsmld_poll - poll method for N_GSM0710
2547 * @tty: terminal device
2548 * @file: file accessing it
2551 * Called when the line discipline is asked to poll() for data or
2552 * for special events. This code is not serialized with respect to
2553 * other events save open/close.
2555 * This code must be sure never to sleep through a hangup.
2556 * Called without the kernel lock held - fine
2559 static __poll_t gsmld_poll(struct tty_struct *tty, struct file *file,
2563 struct gsm_mux *gsm = tty->disc_data;
2565 poll_wait(file, &tty->read_wait, wait);
2566 poll_wait(file, &tty->write_wait, wait);
2570 if (tty_hung_up_p(file))
2572 if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
2574 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
2575 mask |= EPOLLOUT | EPOLLWRNORM;
2579 static int gsmld_config(struct tty_struct *tty, struct gsm_mux *gsm,
2580 struct gsm_config *c)
2583 int need_restart = 0;
2585 /* Stuff we don't support yet - UI or I frame transport, windowing */
2586 if ((c->adaption != 1 && c->adaption != 2) || c->k)
2588 /* Check the MRU/MTU range looks sane */
2589 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8)
2593 if (c->encapsulation > 1) /* Basic, advanced, no I */
2595 if (c->initiator > 1)
2597 if (c->i == 0 || c->i > 2) /* UIH and UI only */
2600 * See what is needed for reconfiguration
2604 if (c->t1 != 0 && c->t1 != gsm->t1)
2606 if (c->t2 != 0 && c->t2 != gsm->t2)
2608 if (c->encapsulation != gsm->encoding)
2610 if (c->adaption != gsm->adaption)
2613 if (c->initiator != gsm->initiator)
2615 if (c->mru != gsm->mru)
2617 if (c->mtu != gsm->mtu)
2621 * Close down what is needed, restart and initiate the new
2625 if (need_close || need_restart) {
2628 ret = gsm_disconnect(gsm);
2634 gsm_cleanup_mux(gsm);
2636 gsm->initiator = c->initiator;
2639 gsm->encoding = c->encapsulation;
2640 gsm->adaption = c->adaption;
2653 /* FIXME: We need to separate activation/deactivation from adding
2654 and removing from the mux array */
2656 gsm_activate_mux(gsm);
2657 if (gsm->initiator && need_close)
2658 gsm_dlci_begin_open(gsm->dlci[0]);
2662 static int gsmld_ioctl(struct tty_struct *tty, struct file *file,
2663 unsigned int cmd, unsigned long arg)
2665 struct gsm_config c;
2666 struct gsm_mux *gsm = tty->disc_data;
2669 case GSMIOC_GETCONF:
2670 memset(&c, 0, sizeof(c));
2671 c.adaption = gsm->adaption;
2672 c.encapsulation = gsm->encoding;
2673 c.initiator = gsm->initiator;
2676 c.t3 = 0; /* Not supported */
2678 if (gsm->ftype == UIH)
2682 pr_debug("Ftype %d i %d\n", gsm->ftype, c.i);
2686 if (copy_to_user((void *)arg, &c, sizeof(c)))
2689 case GSMIOC_SETCONF:
2690 if (copy_from_user(&c, (void *)arg, sizeof(c)))
2692 return gsmld_config(tty, gsm, &c);
2694 return n_tty_ioctl_helper(tty, file, cmd, arg);
2698 #ifdef CONFIG_COMPAT
2699 static long gsmld_compat_ioctl(struct tty_struct *tty, struct file *file,
2700 unsigned int cmd, unsigned long arg)
2702 return gsmld_ioctl(tty, file, cmd, arg);
2711 static int gsm_mux_net_open(struct net_device *net)
2713 pr_debug("%s called\n", __func__);
2714 netif_start_queue(net);
2718 static int gsm_mux_net_close(struct net_device *net)
2720 netif_stop_queue(net);
2724 static void dlci_net_free(struct gsm_dlci *dlci)
2730 dlci->adaption = dlci->prev_adaption;
2731 dlci->data = dlci->prev_data;
2732 free_netdev(dlci->net);
2735 static void net_free(struct kref *ref)
2737 struct gsm_mux_net *mux_net;
2738 struct gsm_dlci *dlci;
2740 mux_net = container_of(ref, struct gsm_mux_net, ref);
2741 dlci = mux_net->dlci;
2744 unregister_netdev(dlci->net);
2745 dlci_net_free(dlci);
2749 static inline void muxnet_get(struct gsm_mux_net *mux_net)
2751 kref_get(&mux_net->ref);
2754 static inline void muxnet_put(struct gsm_mux_net *mux_net)
2756 kref_put(&mux_net->ref, net_free);
2759 static netdev_tx_t gsm_mux_net_start_xmit(struct sk_buff *skb,
2760 struct net_device *net)
2762 struct gsm_mux_net *mux_net = netdev_priv(net);
2763 struct gsm_dlci *dlci = mux_net->dlci;
2764 muxnet_get(mux_net);
2766 skb_queue_head(&dlci->skb_list, skb);
2767 net->stats.tx_packets++;
2768 net->stats.tx_bytes += skb->len;
2769 gsm_dlci_data_kick(dlci);
2770 /* And tell the kernel when the last transmit started. */
2771 netif_trans_update(net);
2772 muxnet_put(mux_net);
2773 return NETDEV_TX_OK;
2776 /* called when a packet did not ack after watchdogtimeout */
2777 static void gsm_mux_net_tx_timeout(struct net_device *net)
2779 /* Tell syslog we are hosed. */
2780 dev_dbg(&net->dev, "Tx timed out.\n");
2782 /* Update statistics */
2783 net->stats.tx_errors++;
2786 static void gsm_mux_rx_netchar(struct gsm_dlci *dlci,
2787 unsigned char *in_buf, int size)
2789 struct net_device *net = dlci->net;
2790 struct sk_buff *skb;
2791 struct gsm_mux_net *mux_net = netdev_priv(net);
2792 muxnet_get(mux_net);
2794 /* Allocate an sk_buff */
2795 skb = dev_alloc_skb(size + NET_IP_ALIGN);
2797 /* We got no receive buffer. */
2798 net->stats.rx_dropped++;
2799 muxnet_put(mux_net);
2802 skb_reserve(skb, NET_IP_ALIGN);
2803 skb_put_data(skb, in_buf, size);
2806 skb->protocol = htons(ETH_P_IP);
2808 /* Ship it off to the kernel */
2811 /* update out statistics */
2812 net->stats.rx_packets++;
2813 net->stats.rx_bytes += size;
2814 muxnet_put(mux_net);
2818 static void gsm_mux_net_init(struct net_device *net)
2820 static const struct net_device_ops gsm_netdev_ops = {
2821 .ndo_open = gsm_mux_net_open,
2822 .ndo_stop = gsm_mux_net_close,
2823 .ndo_start_xmit = gsm_mux_net_start_xmit,
2824 .ndo_tx_timeout = gsm_mux_net_tx_timeout,
2827 net->netdev_ops = &gsm_netdev_ops;
2829 /* fill in the other fields */
2830 net->watchdog_timeo = GSM_NET_TX_TIMEOUT;
2831 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
2832 net->type = ARPHRD_NONE;
2833 net->tx_queue_len = 10;
2837 /* caller holds the dlci mutex */
2838 static void gsm_destroy_network(struct gsm_dlci *dlci)
2840 struct gsm_mux_net *mux_net;
2842 pr_debug("destroy network interface");
2845 mux_net = netdev_priv(dlci->net);
2846 muxnet_put(mux_net);
2850 /* caller holds the dlci mutex */
2851 static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
2855 struct net_device *net;
2856 struct gsm_mux_net *mux_net;
2858 if (!capable(CAP_NET_ADMIN))
2861 /* Already in a non tty mode */
2862 if (dlci->adaption > 2)
2865 if (nc->protocol != htons(ETH_P_IP))
2866 return -EPROTONOSUPPORT;
2868 if (nc->adaption != 3 && nc->adaption != 4)
2869 return -EPROTONOSUPPORT;
2871 pr_debug("create network interface");
2874 if (nc->if_name[0] != '\0')
2875 netname = nc->if_name;
2876 net = alloc_netdev(sizeof(struct gsm_mux_net), netname,
2877 NET_NAME_UNKNOWN, gsm_mux_net_init);
2879 pr_err("alloc_netdev failed");
2882 net->mtu = dlci->gsm->mtu;
2884 net->max_mtu = dlci->gsm->mtu;
2885 mux_net = netdev_priv(net);
2886 mux_net->dlci = dlci;
2887 kref_init(&mux_net->ref);
2888 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */
2890 /* reconfigure dlci for network */
2891 dlci->prev_adaption = dlci->adaption;
2892 dlci->prev_data = dlci->data;
2893 dlci->adaption = nc->adaption;
2894 dlci->data = gsm_mux_rx_netchar;
2897 pr_debug("register netdev");
2898 retval = register_netdev(net);
2900 pr_err("network register fail %d\n", retval);
2901 dlci_net_free(dlci);
2904 return net->ifindex; /* return network index */
2907 /* Line discipline for real tty */
2908 static struct tty_ldisc_ops tty_ldisc_packet = {
2909 .owner = THIS_MODULE,
2910 .magic = TTY_LDISC_MAGIC,
2913 .close = gsmld_close,
2914 .flush_buffer = gsmld_flush_buffer,
2916 .write = gsmld_write,
2917 #ifdef CONFIG_COMPAT
2918 .compat_ioctl = gsmld_compat_ioctl,
2920 .ioctl = gsmld_ioctl,
2922 .receive_buf = gsmld_receive_buf,
2923 .write_wakeup = gsmld_write_wakeup
2932 static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk)
2935 struct gsm_control *ctrl;
2938 modembits[0] = (dlci->addr << 2) | 2 | EA; /* DLCI, Valid, EA */
2939 modembits[1] = (gsm_encode_modem(dlci) << 1) | EA;
2941 modembits[2] = (brk << 4) | 2 | EA; /* Length, Break, EA */
2944 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len);
2947 return gsm_control_wait(dlci->gsm, ctrl);
2950 static int gsm_carrier_raised(struct tty_port *port)
2952 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2953 struct gsm_mux *gsm = dlci->gsm;
2955 /* Not yet open so no carrier info */
2956 if (dlci->state != DLCI_OPEN)
2962 * Basic mode with control channel in ADM mode may not respond
2963 * to CMD_MSC at all and modem_rx is empty.
2965 if (gsm->encoding == 0 && gsm->dlci[0]->mode == DLCI_MODE_ADM &&
2969 return dlci->modem_rx & TIOCM_CD;
2972 static void gsm_dtr_rts(struct tty_port *port, int onoff)
2974 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2975 unsigned int modem_tx = dlci->modem_tx;
2977 modem_tx |= TIOCM_DTR | TIOCM_RTS;
2979 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
2980 if (modem_tx != dlci->modem_tx) {
2981 dlci->modem_tx = modem_tx;
2982 gsmtty_modem_update(dlci, 0);
2986 static const struct tty_port_operations gsm_port_ops = {
2987 .carrier_raised = gsm_carrier_raised,
2988 .dtr_rts = gsm_dtr_rts,
2989 .destruct = gsm_dlci_free,
2992 static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty)
2994 struct gsm_mux *gsm;
2995 struct gsm_dlci *dlci;
2996 unsigned int line = tty->index;
2997 unsigned int mux = line >> 6;
3005 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
3006 if (gsm_mux[mux] == NULL)
3008 if (line == 0 || line > 61) /* 62/63 reserved */
3013 /* If DLCI 0 is not yet fully open return an error.
3014 This is ok from a locking
3015 perspective as we don't have to worry about this
3017 mutex_lock(&gsm->mutex);
3018 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN) {
3019 mutex_unlock(&gsm->mutex);
3022 dlci = gsm->dlci[line];
3025 dlci = gsm_dlci_alloc(gsm, line);
3028 mutex_unlock(&gsm->mutex);
3031 ret = tty_port_install(&dlci->port, driver, tty);
3035 mutex_unlock(&gsm->mutex);
3040 dlci_get(gsm->dlci[0]);
3042 tty->driver_data = dlci;
3043 mutex_unlock(&gsm->mutex);
3048 static int gsmtty_open(struct tty_struct *tty, struct file *filp)
3050 struct gsm_dlci *dlci = tty->driver_data;
3051 struct tty_port *port = &dlci->port;
3054 tty_port_tty_set(port, tty);
3057 /* We could in theory open and close before we wait - eg if we get
3058 a DM straight back. This is ok as that will have caused a hangup */
3059 tty_port_set_initialized(port, 1);
3060 /* Start sending off SABM messages */
3061 gsm_dlci_begin_open(dlci);
3062 /* And wait for virtual carrier */
3063 return tty_port_block_til_ready(port, tty, filp);
3066 static void gsmtty_close(struct tty_struct *tty, struct file *filp)
3068 struct gsm_dlci *dlci = tty->driver_data;
3072 if (dlci->state == DLCI_CLOSED)
3074 mutex_lock(&dlci->mutex);
3075 gsm_destroy_network(dlci);
3076 mutex_unlock(&dlci->mutex);
3077 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
3079 gsm_dlci_begin_close(dlci);
3080 if (tty_port_initialized(&dlci->port) && C_HUPCL(tty))
3081 tty_port_lower_dtr_rts(&dlci->port);
3082 tty_port_close_end(&dlci->port, tty);
3083 tty_port_tty_set(&dlci->port, NULL);
3087 static void gsmtty_hangup(struct tty_struct *tty)
3089 struct gsm_dlci *dlci = tty->driver_data;
3090 if (dlci->state == DLCI_CLOSED)
3092 tty_port_hangup(&dlci->port);
3093 gsm_dlci_begin_close(dlci);
3096 static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf,
3100 struct gsm_dlci *dlci = tty->driver_data;
3101 if (dlci->state == DLCI_CLOSED)
3103 /* Stuff the bytes into the fifo queue */
3104 sent = kfifo_in_locked(dlci->fifo, buf, len, &dlci->lock);
3105 /* Need to kick the channel */
3106 gsm_dlci_data_kick(dlci);
3110 static int gsmtty_write_room(struct tty_struct *tty)
3112 struct gsm_dlci *dlci = tty->driver_data;
3113 if (dlci->state == DLCI_CLOSED)
3115 return TX_SIZE - kfifo_len(dlci->fifo);
3118 static int gsmtty_chars_in_buffer(struct tty_struct *tty)
3120 struct gsm_dlci *dlci = tty->driver_data;
3121 if (dlci->state == DLCI_CLOSED)
3123 return kfifo_len(dlci->fifo);
3126 static void gsmtty_flush_buffer(struct tty_struct *tty)
3128 struct gsm_dlci *dlci = tty->driver_data;
3129 if (dlci->state == DLCI_CLOSED)
3131 /* Caution needed: If we implement reliable transport classes
3132 then the data being transmitted can't simply be junked once
3133 it has first hit the stack. Until then we can just blow it
3135 kfifo_reset(dlci->fifo);
3136 /* Need to unhook this DLCI from the transmit queue logic */
3139 static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
3141 /* The FIFO handles the queue so the kernel will do the right
3142 thing waiting on chars_in_buffer before calling us. No work
3146 static int gsmtty_tiocmget(struct tty_struct *tty)
3148 struct gsm_dlci *dlci = tty->driver_data;
3149 if (dlci->state == DLCI_CLOSED)
3151 return dlci->modem_rx;
3154 static int gsmtty_tiocmset(struct tty_struct *tty,
3155 unsigned int set, unsigned int clear)
3157 struct gsm_dlci *dlci = tty->driver_data;
3158 unsigned int modem_tx = dlci->modem_tx;
3160 if (dlci->state == DLCI_CLOSED)
3165 if (modem_tx != dlci->modem_tx) {
3166 dlci->modem_tx = modem_tx;
3167 return gsmtty_modem_update(dlci, 0);
3173 static int gsmtty_ioctl(struct tty_struct *tty,
3174 unsigned int cmd, unsigned long arg)
3176 struct gsm_dlci *dlci = tty->driver_data;
3177 struct gsm_netconfig nc;
3180 if (dlci->state == DLCI_CLOSED)
3183 case GSMIOC_ENABLE_NET:
3184 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc)))
3186 nc.if_name[IFNAMSIZ-1] = '\0';
3187 /* return net interface index or error code */
3188 mutex_lock(&dlci->mutex);
3189 index = gsm_create_network(dlci, &nc);
3190 mutex_unlock(&dlci->mutex);
3191 if (copy_to_user((void __user *)arg, &nc, sizeof(nc)))
3194 case GSMIOC_DISABLE_NET:
3195 if (!capable(CAP_NET_ADMIN))
3197 mutex_lock(&dlci->mutex);
3198 gsm_destroy_network(dlci);
3199 mutex_unlock(&dlci->mutex);
3202 return -ENOIOCTLCMD;
3206 static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old)
3208 struct gsm_dlci *dlci = tty->driver_data;
3209 if (dlci->state == DLCI_CLOSED)
3211 /* For the moment its fixed. In actual fact the speed information
3212 for the virtual channel can be propogated in both directions by
3213 the RPN control message. This however rapidly gets nasty as we
3214 then have to remap modem signals each way according to whether
3215 our virtual cable is null modem etc .. */
3216 tty_termios_copy_hw(&tty->termios, old);
3219 static void gsmtty_throttle(struct tty_struct *tty)
3221 struct gsm_dlci *dlci = tty->driver_data;
3222 if (dlci->state == DLCI_CLOSED)
3225 dlci->modem_tx &= ~TIOCM_DTR;
3226 dlci->throttled = 1;
3227 /* Send an MSC with DTR cleared */
3228 gsmtty_modem_update(dlci, 0);
3231 static void gsmtty_unthrottle(struct tty_struct *tty)
3233 struct gsm_dlci *dlci = tty->driver_data;
3234 if (dlci->state == DLCI_CLOSED)
3237 dlci->modem_tx |= TIOCM_DTR;
3238 dlci->throttled = 0;
3239 /* Send an MSC with DTR set */
3240 gsmtty_modem_update(dlci, 0);
3243 static int gsmtty_break_ctl(struct tty_struct *tty, int state)
3245 struct gsm_dlci *dlci = tty->driver_data;
3246 int encode = 0; /* Off */
3247 if (dlci->state == DLCI_CLOSED)
3250 if (state == -1) /* "On indefinitely" - we can't encode this
3253 else if (state > 0) {
3254 encode = state / 200; /* mS to encoding */
3256 encode = 0x0F; /* Best effort */
3258 return gsmtty_modem_update(dlci, encode);
3261 static void gsmtty_cleanup(struct tty_struct *tty)
3263 struct gsm_dlci *dlci = tty->driver_data;
3264 struct gsm_mux *gsm = dlci->gsm;
3267 dlci_put(gsm->dlci[0]);
3271 /* Virtual ttys for the demux */
3272 static const struct tty_operations gsmtty_ops = {
3273 .install = gsmtty_install,
3274 .open = gsmtty_open,
3275 .close = gsmtty_close,
3276 .write = gsmtty_write,
3277 .write_room = gsmtty_write_room,
3278 .chars_in_buffer = gsmtty_chars_in_buffer,
3279 .flush_buffer = gsmtty_flush_buffer,
3280 .ioctl = gsmtty_ioctl,
3281 .throttle = gsmtty_throttle,
3282 .unthrottle = gsmtty_unthrottle,
3283 .set_termios = gsmtty_set_termios,
3284 .hangup = gsmtty_hangup,
3285 .wait_until_sent = gsmtty_wait_until_sent,
3286 .tiocmget = gsmtty_tiocmget,
3287 .tiocmset = gsmtty_tiocmset,
3288 .break_ctl = gsmtty_break_ctl,
3289 .cleanup = gsmtty_cleanup,
3294 static int __init gsm_init(void)
3296 /* Fill in our line protocol discipline, and register it */
3297 int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet);
3299 pr_err("n_gsm: can't register line discipline (err = %d)\n",
3304 gsm_tty_driver = alloc_tty_driver(256);
3305 if (!gsm_tty_driver) {
3306 tty_unregister_ldisc(N_GSM0710);
3307 pr_err("gsm_init: tty allocation failed.\n");
3310 gsm_tty_driver->driver_name = "gsmtty";
3311 gsm_tty_driver->name = "gsmtty";
3312 gsm_tty_driver->major = 0; /* Dynamic */
3313 gsm_tty_driver->minor_start = 0;
3314 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
3315 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
3316 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV
3317 | TTY_DRIVER_HARDWARE_BREAK;
3318 gsm_tty_driver->init_termios = tty_std_termios;
3320 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
3321 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
3323 spin_lock_init(&gsm_mux_lock);
3325 if (tty_register_driver(gsm_tty_driver)) {
3326 put_tty_driver(gsm_tty_driver);
3327 tty_unregister_ldisc(N_GSM0710);
3328 pr_err("gsm_init: tty registration failed.\n");
3331 pr_debug("gsm_init: loaded as %d,%d.\n",
3332 gsm_tty_driver->major, gsm_tty_driver->minor_start);
3336 static void __exit gsm_exit(void)
3338 int status = tty_unregister_ldisc(N_GSM0710);
3340 pr_err("n_gsm: can't unregister line discipline (err = %d)\n",
3342 tty_unregister_driver(gsm_tty_driver);
3343 put_tty_driver(gsm_tty_driver);
3346 module_init(gsm_init);
3347 module_exit(gsm_exit);
3350 MODULE_LICENSE("GPL");
3351 MODULE_ALIAS_LDISC(N_GSM0710);