2 * n_gsm.c GSM 0710 tty multiplexor
3 * Copyright (c) 2009/10 Intel Corporation
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
18 * * THIS IS A DEVELOPMENT SNAPSHOT IT IS NOT A FINAL RELEASE *
21 * Mostly done: ioctls for setting modes/timing
22 * Partly done: hooks so you can pull off frames to non tty devs
23 * Restart DLCI 0 when it closes ?
24 * Improve the tx engine
25 * Resolve tx side locking by adding a queue_head and routing
26 * all control traffic via it
27 * General tidy/document
28 * Review the locking/move to refcounts more (mux now moved to an
29 * alloc/free model ready)
30 * Use newest tty open/close port helpers and install hooks
31 * What to do about power functions ?
32 * Termios setting and negotiation
33 * Do we need a 'which mux are you' ioctl to correlate mux and tty sets
37 #include <linux/types.h>
38 #include <linux/major.h>
39 #include <linux/errno.h>
40 #include <linux/signal.h>
41 #include <linux/fcntl.h>
42 #include <linux/sched.h>
43 #include <linux/interrupt.h>
44 #include <linux/tty.h>
45 #include <linux/ctype.h>
47 #include <linux/string.h>
48 #include <linux/slab.h>
49 #include <linux/poll.h>
50 #include <linux/bitops.h>
51 #include <linux/file.h>
52 #include <linux/uaccess.h>
53 #include <linux/module.h>
54 #include <linux/timer.h>
55 #include <linux/tty_flip.h>
56 #include <linux/tty_driver.h>
57 #include <linux/serial.h>
58 #include <linux/kfifo.h>
59 #include <linux/skbuff.h>
62 #include <linux/netdevice.h>
63 #include <linux/etherdevice.h>
64 #include <linux/gsmmux.h>
67 module_param(debug, int, 0600);
69 /* Defaults: these are from the specification */
71 #define T1 10 /* 100mS */
72 #define T2 34 /* 333mS */
73 #define N2 3 /* Retry 3 times */
75 /* Use long timers for testing at low speed with debug on */
82 * Semi-arbitrary buffer size limits. 0710 is normally run with 32-64 byte
83 * limits so this is plenty
87 #define GSM_NET_TX_TIMEOUT (HZ*10)
90 * struct gsm_mux_net - network interface
91 * @struct gsm_dlci* dlci
92 * @struct net_device_stats stats;
94 * Created when net interface is initialized.
98 struct gsm_dlci *dlci;
99 struct net_device_stats stats;
102 #define STATS(net) (((struct gsm_mux_net *)netdev_priv(net))->stats)
105 * Each block of data we have queued to go out is in the form of
106 * a gsm_msg which holds everything we need in a link layer independent
111 struct list_head list;
112 u8 addr; /* DLCI address + flags */
113 u8 ctrl; /* Control byte + flags */
114 unsigned int len; /* Length of data block (can be zero) */
115 unsigned char *data; /* Points into buffer but not at the start */
116 unsigned char buffer[0];
120 * Each active data link has a gsm_dlci structure associated which ties
121 * the link layer to an optional tty (if the tty side is open). To avoid
122 * complexity right now these are only ever freed up when the mux is
125 * At the moment we don't free DLCI objects until the mux is torn down
126 * this avoid object life time issues but might be worth review later.
133 #define DLCI_CLOSED 0
134 #define DLCI_OPENING 1 /* Sending SABM not seen UA */
135 #define DLCI_OPEN 2 /* SABM/UA complete */
136 #define DLCI_CLOSING 3 /* Sending DISC not seen UA/DM */
140 spinlock_t lock; /* Protects the internal state */
141 struct timer_list t1; /* Retransmit timer for SABM and UA */
143 /* Uplink tty if active */
144 struct tty_port port; /* The tty bound to this DLCI if there is one */
145 struct kfifo *fifo; /* Queue fifo for the DLCI */
146 struct kfifo _fifo; /* For new fifo API porting only */
147 int adaption; /* Adaption layer in use */
149 u32 modem_rx; /* Our incoming virtual modem lines */
150 u32 modem_tx; /* Our outgoing modem lines */
151 int dead; /* Refuse re-open */
153 int throttled; /* Private copy of throttle state */
154 int constipated; /* Throttle status for outgoing */
156 struct sk_buff *skb; /* Frame being sent */
157 struct sk_buff_head skb_list; /* Queued frames */
158 /* Data handling callback */
159 void (*data)(struct gsm_dlci *dlci, u8 *data, int len);
160 void (*prev_data)(struct gsm_dlci *dlci, u8 *data, int len);
161 struct net_device *net; /* network interface, if created */
164 /* DLCI 0, 62/63 are special or reseved see gsmtty_open */
169 * DLCI 0 is used to pass control blocks out of band of the data
170 * flow (and with a higher link priority). One command can be outstanding
171 * at a time and we use this structure to manage them. They are created
172 * and destroyed by the user context, and updated by the receive paths
177 u8 cmd; /* Command we are issuing */
178 u8 *data; /* Data for the command in case we retransmit */
179 int len; /* Length of block for retransmission */
180 int done; /* Done flag */
181 int error; /* Error if any */
185 * Each GSM mux we have is represented by this structure. If we are
186 * operating as an ldisc then we use this structure as our ldisc
187 * state. We need to sort out lifetimes and locking with respect
188 * to the gsm mux array. For now we don't free DLCI objects that
189 * have been instantiated until the mux itself is terminated.
191 * To consider further: tty open versus mux shutdown.
195 struct tty_struct *tty; /* The tty our ldisc is bound to */
200 /* Events on the GSM channel */
201 wait_queue_head_t event;
203 /* Bits for GSM mode decoding */
210 #define GSM_ADDRESS 2
211 #define GSM_CONTROL 3
215 #define GSM_OVERRUN 7
220 unsigned int address;
227 u8 *txframe; /* TX framing buffer */
229 /* Methods for the receiver side */
230 void (*receive)(struct gsm_mux *gsm, u8 ch);
231 void (*error)(struct gsm_mux *gsm, u8 ch, u8 flag);
232 /* And transmit side */
233 int (*output)(struct gsm_mux *mux, u8 *data, int len);
238 int initiator; /* Did we initiate connection */
239 int dead; /* Has the mux been shut down */
240 struct gsm_dlci *dlci[NUM_DLCI];
241 int constipated; /* Asked by remote to shut up */
244 unsigned int tx_bytes; /* TX data outstanding */
245 #define TX_THRESH_HI 8192
246 #define TX_THRESH_LO 2048
247 struct list_head tx_list; /* Pending data packets */
249 /* Control messages */
250 struct timer_list t2_timer; /* Retransmit timer for commands */
251 int cretries; /* Command retry counter */
252 struct gsm_control *pending_cmd;/* Our current pending command */
253 spinlock_t control_lock; /* Protects the pending command */
256 int adaption; /* 1 or 2 supported */
257 u8 ftype; /* UI or UIH */
258 int t1, t2; /* Timers in 1/100th of a sec */
259 int n2; /* Retry count */
261 /* Statistics (not currently exposed) */
262 unsigned long bad_fcs;
263 unsigned long malformed;
264 unsigned long io_error;
265 unsigned long bad_size;
266 unsigned long unsupported;
271 * Mux objects - needed so that we can translate a tty index into the
272 * relevant mux and DLCI.
275 #define MAX_MUX 4 /* 256 minors */
276 static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */
277 static spinlock_t gsm_mux_lock;
279 static struct tty_driver *gsm_tty_driver;
282 * This section of the driver logic implements the GSM encodings
283 * both the basic and the 'advanced'. Reliable transport is not
291 /* I is special: the rest are ..*/
302 /* Channel commands */
304 #define CMD_TEST 0x11
307 #define CMD_FCOFF 0x31
310 #define CMD_FCON 0x51
315 /* Virtual modem bits */
322 #define GSM0_SOF 0xF9
323 #define GSM1_SOF 0x7E
324 #define GSM1_ESCAPE 0x7D
325 #define GSM1_ESCAPE_BITS 0x20
329 static const struct tty_port_operations gsm_port_ops;
332 * CRC table for GSM 0710
335 static const u8 gsm_fcs8[256] = {
336 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75,
337 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B,
338 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69,
339 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67,
340 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D,
341 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43,
342 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51,
343 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F,
344 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05,
345 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B,
346 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19,
347 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17,
348 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D,
349 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33,
350 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21,
351 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F,
352 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95,
353 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B,
354 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89,
355 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87,
356 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD,
357 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3,
358 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1,
359 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF,
360 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5,
361 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB,
362 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9,
363 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7,
364 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD,
365 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3,
366 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1,
367 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF
370 #define INIT_FCS 0xFF
371 #define GOOD_FCS 0xCF
374 * gsm_fcs_add - update FCS
378 * Update the FCS to include c. Uses the algorithm in the specification
382 static inline u8 gsm_fcs_add(u8 fcs, u8 c)
384 return gsm_fcs8[fcs ^ c];
388 * gsm_fcs_add_block - update FCS for a block
391 * @len: length of buffer
393 * Update the FCS to include c. Uses the algorithm in the specification
397 static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len)
400 fcs = gsm_fcs8[fcs ^ *c++];
405 * gsm_read_ea - read a byte into an EA
406 * @val: variable holding value
407 * c: byte going into the EA
409 * Processes one byte of an EA. Updates the passed variable
410 * and returns 1 if the EA is now completely read
413 static int gsm_read_ea(unsigned int *val, u8 c)
415 /* Add the next 7 bits into the value */
418 /* Was this the last byte of the EA 1 = yes*/
423 * gsm_encode_modem - encode modem data bits
424 * @dlci: DLCI to encode from
426 * Returns the correct GSM encoded modem status bits (6 bit field) for
427 * the current status of the DLCI and attached tty object
430 static u8 gsm_encode_modem(const struct gsm_dlci *dlci)
433 /* FC is true flow control not modem bits */
436 if (dlci->modem_tx & TIOCM_DTR)
437 modembits |= MDM_RTC;
438 if (dlci->modem_tx & TIOCM_RTS)
439 modembits |= MDM_RTR;
440 if (dlci->modem_tx & TIOCM_RI)
442 if (dlci->modem_tx & TIOCM_CD)
448 * gsm_print_packet - display a frame for debug
449 * @hdr: header to print before decode
450 * @addr: address EA from the frame
451 * @cr: C/R bit from the frame
452 * @control: control including PF bit
453 * @data: following data bytes
454 * @dlen: length of data
456 * Displays a packet in human readable format for debugging purposes. The
457 * style is based on amateur radio LAP-B dump display.
460 static void gsm_print_packet(const char *hdr, int addr, int cr,
461 u8 control, const u8 *data, int dlen)
466 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]);
468 switch (control & ~PF) {
488 if (!(control & 0x01)) {
489 pr_cont("I N(S)%d N(R)%d",
490 (control & 0x0E) >> 1, (control & 0xE0) >> 5);
491 } else switch (control & 0x0F) {
493 pr_cont("RR(%d)", (control & 0xE0) >> 5);
496 pr_cont("RNR(%d)", (control & 0xE0) >> 5);
499 pr_cont("REJ(%d)", (control & 0xE0) >> 5);
502 pr_cont("[%02X]", control);
518 pr_cont("%02X ", *data++);
527 * Link level transmission side
531 * gsm_stuff_packet - bytestuff a packet
534 * @len: length of input
536 * Expand a buffer by bytestuffing it. The worst case size change
537 * is doubling and the caller is responsible for handing out
538 * suitable sized buffers.
541 static int gsm_stuff_frame(const u8 *input, u8 *output, int len)
545 if (*input == GSM1_SOF || *input == GSM1_ESCAPE
546 || *input == XON || *input == XOFF) {
547 *output++ = GSM1_ESCAPE;
548 *output++ = *input++ ^ GSM1_ESCAPE_BITS;
551 *output++ = *input++;
558 * gsm_send - send a control frame
560 * @addr: address for control frame
561 * @cr: command/response bit
562 * @control: control byte including PF bit
564 * Format up and transmit a control frame. These do not go via the
565 * queueing logic as they should be transmitted ahead of data when
568 * FIXME: Lock versus data TX path
571 static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control)
577 switch (gsm->encoding) {
580 cbuf[1] = (addr << 2) | (cr << 1) | EA;
582 cbuf[3] = EA; /* Length of data = 0 */
583 cbuf[4] = 0xFF - gsm_fcs_add_block(INIT_FCS, cbuf + 1, 3);
589 /* Control frame + packing (but not frame stuffing) in mode 1 */
590 ibuf[0] = (addr << 2) | (cr << 1) | EA;
592 ibuf[2] = 0xFF - gsm_fcs_add_block(INIT_FCS, ibuf, 2);
593 /* Stuffing may double the size worst case */
594 len = gsm_stuff_frame(ibuf, cbuf + 1, 3);
595 /* Now add the SOF markers */
597 cbuf[len + 1] = GSM1_SOF;
598 /* FIXME: we can omit the lead one in many cases */
605 gsm->output(gsm, cbuf, len);
606 gsm_print_packet("-->", addr, cr, control, NULL, 0);
610 * gsm_response - send a control response
612 * @addr: address for control frame
613 * @control: control byte including PF bit
615 * Format up and transmit a link level response frame.
618 static inline void gsm_response(struct gsm_mux *gsm, int addr, int control)
620 gsm_send(gsm, addr, 0, control);
624 * gsm_command - send a control command
626 * @addr: address for control frame
627 * @control: control byte including PF bit
629 * Format up and transmit a link level command frame.
632 static inline void gsm_command(struct gsm_mux *gsm, int addr, int control)
634 gsm_send(gsm, addr, 1, control);
637 /* Data transmission */
639 #define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */
642 * gsm_data_alloc - allocate data frame
644 * @addr: DLCI address
645 * @len: length excluding header and FCS
646 * @ctrl: control byte
648 * Allocate a new data buffer for sending frames with data. Space is left
649 * at the front for header bytes but that is treated as an implementation
650 * detail and not for the high level code to use
653 static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
656 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN,
660 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */
664 INIT_LIST_HEAD(&m->list);
669 * gsm_data_kick - poke the queue
672 * The tty device has called us to indicate that room has appeared in
673 * the transmit queue. Ram more data into the pipe if we have any
674 * If we have been flow-stopped by a CMD_FCOFF, then we can only
675 * send messages on DLCI0 until CMD_FCON
677 * FIXME: lock against link layer control transmissions
680 static void gsm_data_kick(struct gsm_mux *gsm)
682 struct gsm_msg *msg, *nmsg;
686 list_for_each_entry_safe(msg, nmsg, &gsm->tx_list, list) {
687 if (gsm->constipated && msg->addr)
689 if (gsm->encoding != 0) {
690 gsm->txframe[0] = GSM1_SOF;
691 len = gsm_stuff_frame(msg->data,
692 gsm->txframe + 1, msg->len);
693 gsm->txframe[len + 1] = GSM1_SOF;
696 gsm->txframe[0] = GSM0_SOF;
697 memcpy(gsm->txframe + 1 , msg->data, msg->len);
698 gsm->txframe[msg->len + 1] = GSM0_SOF;
703 print_hex_dump_bytes("gsm_data_kick: ",
707 if (gsm->output(gsm, gsm->txframe + skip_sof,
710 /* FIXME: Can eliminate one SOF in many more cases */
711 gsm->tx_bytes -= msg->len;
712 /* For a burst of frames skip the extra SOF within the
716 list_del(&msg->list);
722 * __gsm_data_queue - queue a UI or UIH frame
723 * @dlci: DLCI sending the data
724 * @msg: message queued
726 * Add data to the transmit queue and try and get stuff moving
727 * out of the mux tty if not already doing so. The Caller must hold
731 static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
733 struct gsm_mux *gsm = dlci->gsm;
735 u8 *fcs = dp + msg->len;
737 /* Fill in the header */
738 if (gsm->encoding == 0) {
740 *--dp = (msg->len << 1) | EA;
742 *--dp = (msg->len >> 7); /* bits 7 - 15 */
743 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */
749 *--dp = (msg->addr << 2) | 2 | EA;
751 *--dp = (msg->addr << 2) | EA;
752 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp);
753 /* Ugly protocol layering violation */
754 if (msg->ctrl == UI || msg->ctrl == (UI|PF))
755 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len);
758 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl,
759 msg->data, msg->len);
761 /* Move the header back and adjust the length, also allow for the FCS
762 now tacked on the end */
763 msg->len += (msg->data - dp) + 1;
766 /* Add to the actual output queue */
767 list_add_tail(&msg->list, &gsm->tx_list);
768 gsm->tx_bytes += msg->len;
773 * gsm_data_queue - queue a UI or UIH frame
774 * @dlci: DLCI sending the data
775 * @msg: message queued
777 * Add data to the transmit queue and try and get stuff moving
778 * out of the mux tty if not already doing so. Take the
779 * the gsm tx lock and dlci lock.
782 static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
785 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
786 __gsm_data_queue(dlci, msg);
787 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
791 * gsm_dlci_data_output - try and push data out of a DLCI
793 * @dlci: the DLCI to pull data from
795 * Pull data from a DLCI and send it into the transmit queue if there
796 * is data. Keep to the MRU of the mux. This path handles the usual tty
797 * interface which is a byte stream with optional modem data.
799 * Caller must hold the tx_lock of the mux.
802 static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci)
806 int len, total_size, size;
807 int h = dlci->adaption - 1;
811 len = kfifo_len(dlci->fifo);
815 /* MTU/MRU count only the data bits */
821 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
822 /* FIXME: need a timer or something to kick this so it can't
823 get stuck with no work outstanding and no buffer free */
827 switch (dlci->adaption) {
828 case 1: /* Unstructured */
830 case 2: /* Unstructed with modem bits. Always one byte as we never
831 send inline break data */
832 *dp++ = gsm_encode_modem(dlci);
835 WARN_ON(kfifo_out_locked(dlci->fifo, dp , len, &dlci->lock) != len);
836 __gsm_data_queue(dlci, msg);
839 /* Bytes of data we used up */
844 * gsm_dlci_data_output_framed - try and push data out of a DLCI
846 * @dlci: the DLCI to pull data from
848 * Pull data from a DLCI and send it into the transmit queue if there
849 * is data. Keep to the MRU of the mux. This path handles framed data
850 * queued as skbuffs to the DLCI.
852 * Caller must hold the tx_lock of the mux.
855 static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
856 struct gsm_dlci *dlci)
861 int last = 0, first = 0;
864 /* One byte per frame is used for B/F flags */
865 if (dlci->adaption == 4)
868 /* dlci->skb is locked by tx_lock */
869 if (dlci->skb == NULL) {
870 dlci->skb = skb_dequeue_tail(&dlci->skb_list);
871 if (dlci->skb == NULL)
875 len = dlci->skb->len + overhead;
877 /* MTU/MRU count only the data bits */
878 if (len > gsm->mtu) {
879 if (dlci->adaption == 3) {
880 /* Over long frame, bin it */
881 dev_kfree_skb_any(dlci->skb);
889 size = len + overhead;
890 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
892 /* FIXME: need a timer or something to kick this so it can't
893 get stuck with no work outstanding and no buffer free */
895 skb_queue_tail(&dlci->skb_list, dlci->skb);
901 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */
902 /* Flag byte to carry the start/end info */
903 *dp++ = last << 7 | first << 6 | 1; /* EA */
906 memcpy(dp, dlci->skb->data, len);
907 skb_pull(dlci->skb, len);
908 __gsm_data_queue(dlci, msg);
910 dev_kfree_skb_any(dlci->skb);
917 * gsm_dlci_data_sweep - look for data to send
920 * Sweep the GSM mux channels in priority order looking for ones with
921 * data to send. We could do with optimising this scan a bit. We aim
922 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit
923 * TX_THRESH_LO we get called again
925 * FIXME: We should round robin between groups and in theory you can
926 * renegotiate DLCI priorities with optional stuff. Needs optimising.
929 static void gsm_dlci_data_sweep(struct gsm_mux *gsm)
932 /* Priority ordering: We should do priority with RR of the groups */
935 while (i < NUM_DLCI) {
936 struct gsm_dlci *dlci;
938 if (gsm->tx_bytes > TX_THRESH_HI)
941 if (dlci == NULL || dlci->constipated) {
945 if (dlci->adaption < 3 && !dlci->net)
946 len = gsm_dlci_data_output(gsm, dlci);
948 len = gsm_dlci_data_output_framed(gsm, dlci);
951 /* DLCI empty - try the next */
958 * gsm_dlci_data_kick - transmit if possible
959 * @dlci: DLCI to kick
961 * Transmit data from this DLCI if the queue is empty. We can't rely on
962 * a tty wakeup except when we filled the pipe so we need to fire off
963 * new data ourselves in other cases.
966 static void gsm_dlci_data_kick(struct gsm_dlci *dlci)
971 if (dlci->constipated)
974 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
975 /* If we have nothing running then we need to fire up */
976 sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO);
977 if (dlci->gsm->tx_bytes == 0) {
979 gsm_dlci_data_output_framed(dlci->gsm, dlci);
981 gsm_dlci_data_output(dlci->gsm, dlci);
984 gsm_dlci_data_sweep(dlci->gsm);
985 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
989 * Control message processing
994 * gsm_control_reply - send a response frame to a control
996 * @cmd: the command to use
997 * @data: data to follow encoded info
998 * @dlen: length of data
1000 * Encode up and queue a UI/UIH frame containing our response.
1003 static void gsm_control_reply(struct gsm_mux *gsm, int cmd, u8 *data,
1006 struct gsm_msg *msg;
1007 msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype);
1010 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */
1011 msg->data[1] = (dlen << 1) | EA;
1012 memcpy(msg->data + 2, data, dlen);
1013 gsm_data_queue(gsm->dlci[0], msg);
1017 * gsm_process_modem - process received modem status
1018 * @tty: virtual tty bound to the DLCI
1019 * @dlci: DLCI to affect
1020 * @modem: modem bits (full EA)
1022 * Used when a modem control message or line state inline in adaption
1023 * layer 2 is processed. Sort out the local modem state and throttles
1026 static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
1027 u32 modem, int clen)
1033 /* The modem status command can either contain one octet (v.24 signals)
1034 or two octets (v.24 signals + break signals). The length field will
1035 either be 2 or 3 respectively. This is specified in section
1036 5.4.6.3.7 of the 27.010 mux spec. */
1039 modem = modem & 0x7f;
1042 modem = (modem >> 7) & 0x7f;
1045 /* Flow control/ready to communicate */
1046 fc = (modem & MDM_FC) || !(modem & MDM_RTR);
1047 if (fc && !dlci->constipated) {
1048 /* Need to throttle our output on this device */
1049 dlci->constipated = 1;
1050 } else if (!fc && dlci->constipated) {
1051 dlci->constipated = 0;
1052 gsm_dlci_data_kick(dlci);
1055 /* Map modem bits */
1056 if (modem & MDM_RTC)
1057 mlines |= TIOCM_DSR | TIOCM_DTR;
1058 if (modem & MDM_RTR)
1059 mlines |= TIOCM_RTS | TIOCM_CTS;
1065 /* Carrier drop -> hangup */
1067 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD))
1068 if (!(tty->termios.c_cflag & CLOCAL))
1071 tty_insert_flip_char(tty, 0, TTY_BREAK);
1073 dlci->modem_rx = mlines;
1077 * gsm_control_modem - modem status received
1079 * @data: data following command
1080 * @clen: command length
1082 * We have received a modem status control message. This is used by
1083 * the GSM mux protocol to pass virtual modem line status and optionally
1084 * to indicate break signals. Unpack it, convert to Linux representation
1085 * and if need be stuff a break message down the tty.
1088 static void gsm_control_modem(struct gsm_mux *gsm, u8 *data, int clen)
1090 unsigned int addr = 0;
1091 unsigned int modem = 0;
1092 struct gsm_dlci *dlci;
1095 struct tty_struct *tty;
1097 while (gsm_read_ea(&addr, *dp++) == 0) {
1102 /* Must be at least one byte following the EA */
1108 /* Closed port, or invalid ? */
1109 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1111 dlci = gsm->dlci[addr];
1113 while (gsm_read_ea(&modem, *dp++) == 0) {
1118 tty = tty_port_tty_get(&dlci->port);
1119 gsm_process_modem(tty, dlci, modem, clen);
1124 gsm_control_reply(gsm, CMD_MSC, data, clen);
1128 * gsm_control_rls - remote line status
1131 * @clen: data length
1133 * The modem sends us a two byte message on the control channel whenever
1134 * it wishes to send us an error state from the virtual link. Stuff
1135 * this into the uplink tty if present
1138 static void gsm_control_rls(struct gsm_mux *gsm, u8 *data, int clen)
1140 struct tty_struct *tty;
1141 unsigned int addr = 0 ;
1146 while (gsm_read_ea(&addr, *dp++) == 0) {
1151 /* Must be at least one byte following ea */
1156 /* Closed port, or invalid ? */
1157 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1161 if ((bits & 1) == 0)
1163 /* See if we have an uplink tty */
1164 tty = tty_port_tty_get(&gsm->dlci[addr]->port);
1168 tty_insert_flip_char(tty, 0, TTY_OVERRUN);
1170 tty_insert_flip_char(tty, 0, TTY_PARITY);
1172 tty_insert_flip_char(tty, 0, TTY_FRAME);
1173 tty_flip_buffer_push(tty);
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,
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 = 0;
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);
1221 spin_unlock_irqrestore(&gsm->tx_lock, flags);
1224 /* Modem wants us to STFU */
1225 gsm->constipated = 1;
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,
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 * @data: pointer to 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(unsigned long data)
1320 struct gsm_mux *gsm = (struct gsm_mux *)data;
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 * @len: 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;
1372 gsm->cretries = gsm->n2;
1373 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1374 gsm_control_transmit(gsm, ctrl);
1375 spin_unlock_irqrestore(&gsm->control_lock, flags);
1380 * gsm_control_wait - wait for a control to finish
1382 * @control: control we are waiting on
1384 * Waits for the control to complete or time out. Frees any used
1385 * resources and returns 0 for success, or an error if the remote
1386 * rejected or ignored the request.
1389 static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
1392 wait_event(gsm->event, control->done == 1);
1393 err = control->error;
1400 * DLCI level handling: Needs krefs
1404 * State transitions and timers
1408 * gsm_dlci_close - a DLCI has closed
1409 * @dlci: DLCI that closed
1411 * Perform processing when moving a DLCI into closed state. If there
1412 * is an attached tty this is hung up
1415 static void gsm_dlci_close(struct gsm_dlci *dlci)
1417 del_timer(&dlci->t1);
1419 pr_debug("DLCI %d goes closed.\n", dlci->addr);
1420 dlci->state = DLCI_CLOSED;
1421 if (dlci->addr != 0) {
1422 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1427 kfifo_reset(dlci->fifo);
1429 dlci->gsm->dead = 1;
1430 wake_up(&dlci->gsm->event);
1431 /* A DLCI 0 close is a MUX termination so we need to kick that
1432 back to userspace somehow */
1436 * gsm_dlci_open - a DLCI has opened
1437 * @dlci: DLCI that opened
1439 * Perform processing when moving a DLCI into open state.
1442 static void gsm_dlci_open(struct gsm_dlci *dlci)
1444 /* Note that SABM UA .. SABM UA first UA lost can mean that we go
1446 del_timer(&dlci->t1);
1447 /* This will let a tty open continue */
1448 dlci->state = DLCI_OPEN;
1450 pr_debug("DLCI %d goes open.\n", dlci->addr);
1451 wake_up(&dlci->gsm->event);
1455 * gsm_dlci_t1 - T1 timer expiry
1456 * @dlci: DLCI that opened
1458 * The T1 timer handles retransmits of control frames (essentially of
1459 * SABM and DISC). We resend the command until the retry count runs out
1460 * in which case an opening port goes back to closed and a closing port
1461 * is simply put into closed state (any further frames from the other
1462 * end will get a DM response)
1465 static void gsm_dlci_t1(unsigned long data)
1467 struct gsm_dlci *dlci = (struct gsm_dlci *)data;
1468 struct gsm_mux *gsm = dlci->gsm;
1470 switch (dlci->state) {
1473 if (dlci->retries) {
1474 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1475 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1477 gsm_dlci_close(dlci);
1481 if (dlci->retries) {
1482 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1483 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1485 gsm_dlci_close(dlci);
1491 * gsm_dlci_begin_open - start channel open procedure
1492 * @dlci: DLCI to open
1494 * Commence opening a DLCI from the Linux side. We issue SABM messages
1495 * to the modem which should then reply with a UA, at which point we
1496 * will move into open state. Opening is done asynchronously with retry
1497 * running off timers and the responses.
1500 static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
1502 struct gsm_mux *gsm = dlci->gsm;
1503 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING)
1505 dlci->retries = gsm->n2;
1506 dlci->state = DLCI_OPENING;
1507 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1508 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1512 * gsm_dlci_begin_close - start channel open procedure
1513 * @dlci: DLCI to open
1515 * Commence closing a DLCI from the Linux side. We issue DISC messages
1516 * to the modem which should then reply with a UA, at which point we
1517 * will move into closed state. Closing is done asynchronously with retry
1518 * off timers. We may also receive a DM reply from the other end which
1519 * indicates the channel was already closed.
1522 static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
1524 struct gsm_mux *gsm = dlci->gsm;
1525 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
1527 dlci->retries = gsm->n2;
1528 dlci->state = DLCI_CLOSING;
1529 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1530 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1534 * gsm_dlci_data - data arrived
1536 * @data: block of bytes received
1537 * @len: length of received block
1539 * A UI or UIH frame has arrived which contains data for a channel
1540 * other than the control channel. If the relevant virtual tty is
1541 * open we shovel the bits down it, if not we drop them.
1544 static void gsm_dlci_data(struct gsm_dlci *dlci, u8 *data, int clen)
1547 struct tty_port *port = &dlci->port;
1548 struct tty_struct *tty = tty_port_tty_get(port);
1549 unsigned int modem = 0;
1553 pr_debug("%d bytes for tty %p\n", len, tty);
1555 switch (dlci->adaption) {
1556 /* Unsupported types */
1557 /* Packetised interruptible data */
1560 /* Packetised uininterruptible voice/data */
1563 /* Asynchronous serial with line state in each frame */
1565 while (gsm_read_ea(&modem, *data++) == 0) {
1570 gsm_process_modem(tty, dlci, modem, clen);
1571 /* Line state will go via DLCI 0 controls only */
1574 tty_insert_flip_string(tty, data, len);
1575 tty_flip_buffer_push(tty);
1582 * gsm_dlci_control - data arrived on control channel
1584 * @data: block of bytes received
1585 * @len: length of received block
1587 * A UI or UIH frame has arrived which contains data for DLCI 0 the
1588 * control channel. This should contain a command EA followed by
1589 * control data bytes. The command EA contains a command/response bit
1590 * and we divide up the work accordingly.
1593 static void gsm_dlci_command(struct gsm_dlci *dlci, u8 *data, int len)
1595 /* See what command is involved */
1596 unsigned int command = 0;
1598 if (gsm_read_ea(&command, *data++) == 1) {
1601 /* FIXME: this is properly an EA */
1603 /* Malformed command ? */
1607 gsm_control_message(dlci->gsm, command,
1610 gsm_control_response(dlci->gsm, command,
1618 * Allocate/Free DLCI channels
1622 * gsm_dlci_alloc - allocate a DLCI
1624 * @addr: address of the DLCI
1626 * Allocate and install a new DLCI object into the GSM mux.
1628 * FIXME: review locking races
1631 static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
1633 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC);
1636 spin_lock_init(&dlci->lock);
1637 mutex_init(&dlci->mutex);
1638 dlci->fifo = &dlci->_fifo;
1639 if (kfifo_alloc(&dlci->_fifo, 4096, GFP_KERNEL) < 0) {
1644 skb_queue_head_init(&dlci->skb_list);
1645 init_timer(&dlci->t1);
1646 dlci->t1.function = gsm_dlci_t1;
1647 dlci->t1.data = (unsigned long)dlci;
1648 tty_port_init(&dlci->port);
1649 dlci->port.ops = &gsm_port_ops;
1652 dlci->adaption = gsm->adaption;
1653 dlci->state = DLCI_CLOSED;
1655 dlci->data = gsm_dlci_data;
1657 dlci->data = gsm_dlci_command;
1658 gsm->dlci[addr] = dlci;
1663 * gsm_dlci_free - free DLCI
1664 * @dlci: DLCI to free
1670 static void gsm_dlci_free(struct tty_port *port)
1672 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
1674 del_timer_sync(&dlci->t1);
1675 dlci->gsm->dlci[dlci->addr] = NULL;
1676 kfifo_free(dlci->fifo);
1677 while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
1678 dev_kfree_skb(dlci->skb);
1682 static inline void dlci_get(struct gsm_dlci *dlci)
1684 tty_port_get(&dlci->port);
1687 static inline void dlci_put(struct gsm_dlci *dlci)
1689 tty_port_put(&dlci->port);
1693 * gsm_dlci_release - release DLCI
1694 * @dlci: DLCI to destroy
1696 * Release a DLCI. Actual free is deferred until either
1697 * mux is closed or tty is closed - whichever is last.
1701 static void gsm_dlci_release(struct gsm_dlci *dlci)
1703 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1712 * LAPBish link layer logic
1716 * gsm_queue - a GSM frame is ready to process
1717 * @gsm: pointer to our gsm mux
1719 * At this point in time a frame has arrived and been demangled from
1720 * the line encoding. All the differences between the encodings have
1721 * been handled below us and the frame is unpacked into the structures.
1722 * The fcs holds the header FCS but any data FCS must be added here.
1725 static void gsm_queue(struct gsm_mux *gsm)
1727 struct gsm_dlci *dlci;
1730 /* We have to sneak a look at the packet body to do the FCS.
1731 A somewhat layering violation in the spec */
1733 if ((gsm->control & ~PF) == UI)
1734 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len);
1735 if (gsm->encoding == 0){
1736 /* WARNING: gsm->received_fcs is used for gsm->encoding = 0 only.
1737 In this case it contain the last piece of data
1738 required to generate final CRC */
1739 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs);
1741 if (gsm->fcs != GOOD_FCS) {
1744 pr_debug("BAD FCS %02x\n", gsm->fcs);
1747 address = gsm->address >> 1;
1748 if (address >= NUM_DLCI)
1751 cr = gsm->address & 1; /* C/R bit */
1753 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
1755 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */
1756 dlci = gsm->dlci[address];
1758 switch (gsm->control) {
1763 dlci = gsm_dlci_alloc(gsm, address);
1767 gsm_response(gsm, address, DM);
1769 gsm_response(gsm, address, UA);
1770 gsm_dlci_open(dlci);
1776 if (dlci == NULL || dlci->state == DLCI_CLOSED) {
1777 gsm_response(gsm, address, DM);
1780 /* Real close complete */
1781 gsm_response(gsm, address, UA);
1782 gsm_dlci_close(dlci);
1786 if (cr == 0 || dlci == NULL)
1788 switch (dlci->state) {
1790 gsm_dlci_close(dlci);
1793 gsm_dlci_open(dlci);
1797 case DM: /* DM can be valid unsolicited */
1803 gsm_dlci_close(dlci);
1813 if (dlci == NULL || dlci->state != DLCI_OPEN) {
1814 gsm_command(gsm, address, DM|PF);
1817 dlci->data(dlci, gsm->buf, gsm->len);
1830 * gsm0_receive - perform processing for non-transparency
1831 * @gsm: gsm data for this ldisc instance
1834 * Receive bytes in gsm mode 0
1837 static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
1841 switch (gsm->state) {
1842 case GSM_SEARCH: /* SOF marker */
1843 if (c == GSM0_SOF) {
1844 gsm->state = GSM_ADDRESS;
1847 gsm->fcs = INIT_FCS;
1850 case GSM_ADDRESS: /* Address EA */
1851 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1852 if (gsm_read_ea(&gsm->address, c))
1853 gsm->state = GSM_CONTROL;
1855 case GSM_CONTROL: /* Control Byte */
1856 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1858 gsm->state = GSM_LEN0;
1860 case GSM_LEN0: /* Length EA */
1861 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1862 if (gsm_read_ea(&gsm->len, c)) {
1863 if (gsm->len > gsm->mru) {
1865 gsm->state = GSM_SEARCH;
1870 gsm->state = GSM_FCS;
1872 gsm->state = GSM_DATA;
1875 gsm->state = GSM_LEN1;
1878 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1880 gsm->len |= len << 7;
1881 if (gsm->len > gsm->mru) {
1883 gsm->state = GSM_SEARCH;
1888 gsm->state = GSM_FCS;
1890 gsm->state = GSM_DATA;
1892 case GSM_DATA: /* Data */
1893 gsm->buf[gsm->count++] = c;
1894 if (gsm->count == gsm->len)
1895 gsm->state = GSM_FCS;
1897 case GSM_FCS: /* FCS follows the packet */
1898 gsm->received_fcs = c;
1900 gsm->state = GSM_SSOF;
1903 if (c == GSM0_SOF) {
1904 gsm->state = GSM_SEARCH;
1912 * gsm1_receive - perform processing for non-transparency
1913 * @gsm: gsm data for this ldisc instance
1916 * Receive bytes in mode 1 (Advanced option)
1919 static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
1921 if (c == GSM1_SOF) {
1922 /* EOF is only valid in frame if we have got to the data state
1923 and received at least one byte (the FCS) */
1924 if (gsm->state == GSM_DATA && gsm->count) {
1925 /* Extract the FCS */
1927 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
1928 gsm->len = gsm->count;
1930 gsm->state = GSM_START;
1933 /* Any partial frame was a runt so go back to start */
1934 if (gsm->state != GSM_START) {
1936 gsm->state = GSM_START;
1938 /* A SOF in GSM_START means we are still reading idling or
1943 if (c == GSM1_ESCAPE) {
1948 /* Only an unescaped SOF gets us out of GSM search */
1949 if (gsm->state == GSM_SEARCH)
1953 c ^= GSM1_ESCAPE_BITS;
1956 switch (gsm->state) {
1957 case GSM_START: /* First byte after SOF */
1959 gsm->state = GSM_ADDRESS;
1960 gsm->fcs = INIT_FCS;
1962 case GSM_ADDRESS: /* Address continuation */
1963 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1964 if (gsm_read_ea(&gsm->address, c))
1965 gsm->state = GSM_CONTROL;
1967 case GSM_CONTROL: /* Control Byte */
1968 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1971 gsm->state = GSM_DATA;
1973 case GSM_DATA: /* Data */
1974 if (gsm->count > gsm->mru) { /* Allow one for the FCS */
1975 gsm->state = GSM_OVERRUN;
1978 gsm->buf[gsm->count++] = c;
1980 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */
1986 * gsm_error - handle tty error
1988 * @data: byte received (may be invalid)
1989 * @flag: error received
1991 * Handle an error in the receipt of data for a frame. Currently we just
1992 * go back to hunting for a SOF.
1994 * FIXME: better diagnostics ?
1997 static void gsm_error(struct gsm_mux *gsm,
1998 unsigned char data, unsigned char flag)
2000 gsm->state = GSM_SEARCH;
2005 * gsm_cleanup_mux - generic GSM protocol cleanup
2008 * Clean up the bits of the mux which are the same for all framing
2009 * protocols. Remove the mux from the mux table, stop all the timers
2010 * and then shut down each device hanging up the channels as we go.
2013 void gsm_cleanup_mux(struct gsm_mux *gsm)
2016 struct gsm_dlci *dlci = gsm->dlci[0];
2017 struct gsm_msg *txq, *ntxq;
2018 struct gsm_control *gc;
2022 spin_lock(&gsm_mux_lock);
2023 for (i = 0; i < MAX_MUX; i++) {
2024 if (gsm_mux[i] == gsm) {
2029 spin_unlock(&gsm_mux_lock);
2030 WARN_ON(i == MAX_MUX);
2032 /* In theory disconnecting DLCI 0 is sufficient but for some
2033 modems this is apparently not the case. */
2035 gc = gsm_control_send(gsm, CMD_CLD, NULL, 0);
2037 gsm_control_wait(gsm, gc);
2039 del_timer_sync(&gsm->t2_timer);
2040 /* Now we are sure T2 has stopped */
2043 gsm_dlci_begin_close(dlci);
2044 wait_event_interruptible(gsm->event,
2045 dlci->state == DLCI_CLOSED);
2047 /* Free up any link layer users */
2048 for (i = 0; i < NUM_DLCI; i++)
2050 gsm_dlci_release(gsm->dlci[i]);
2051 /* Now wipe the queues */
2052 list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list)
2054 INIT_LIST_HEAD(&gsm->tx_list);
2056 EXPORT_SYMBOL_GPL(gsm_cleanup_mux);
2059 * gsm_activate_mux - generic GSM setup
2062 * Set up the bits of the mux which are the same for all framing
2063 * protocols. Add the mux to the mux table so it can be opened and
2064 * finally kick off connecting to DLCI 0 on the modem.
2067 int gsm_activate_mux(struct gsm_mux *gsm)
2069 struct gsm_dlci *dlci;
2072 init_timer(&gsm->t2_timer);
2073 gsm->t2_timer.function = gsm_control_retransmit;
2074 gsm->t2_timer.data = (unsigned long)gsm;
2075 init_waitqueue_head(&gsm->event);
2076 spin_lock_init(&gsm->control_lock);
2077 spin_lock_init(&gsm->tx_lock);
2079 if (gsm->encoding == 0)
2080 gsm->receive = gsm0_receive;
2082 gsm->receive = gsm1_receive;
2083 gsm->error = gsm_error;
2085 spin_lock(&gsm_mux_lock);
2086 for (i = 0; i < MAX_MUX; i++) {
2087 if (gsm_mux[i] == NULL) {
2093 spin_unlock(&gsm_mux_lock);
2097 dlci = gsm_dlci_alloc(gsm, 0);
2100 gsm->dead = 0; /* Tty opens are now permissible */
2103 EXPORT_SYMBOL_GPL(gsm_activate_mux);
2106 * gsm_free_mux - free up a mux
2109 * Dispose of allocated resources for a dead mux
2111 void gsm_free_mux(struct gsm_mux *gsm)
2113 kfree(gsm->txframe);
2117 EXPORT_SYMBOL_GPL(gsm_free_mux);
2120 * gsm_free_muxr - free up a mux
2123 * Dispose of allocated resources for a dead mux
2125 static void gsm_free_muxr(struct kref *ref)
2127 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref);
2131 static inline void mux_get(struct gsm_mux *gsm)
2133 kref_get(&gsm->ref);
2136 static inline void mux_put(struct gsm_mux *gsm)
2138 kref_put(&gsm->ref, gsm_free_muxr);
2142 * gsm_alloc_mux - allocate a mux
2144 * Creates a new mux ready for activation.
2147 struct gsm_mux *gsm_alloc_mux(void)
2149 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
2152 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL);
2153 if (gsm->buf == NULL) {
2157 gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL);
2158 if (gsm->txframe == NULL) {
2163 spin_lock_init(&gsm->lock);
2164 kref_init(&gsm->ref);
2165 INIT_LIST_HEAD(&gsm->tx_list);
2173 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
2175 gsm->dead = 1; /* Avoid early tty opens */
2179 EXPORT_SYMBOL_GPL(gsm_alloc_mux);
2182 * gsmld_output - write to link
2184 * @data: bytes to output
2187 * Write a block of data from the GSM mux to the data channel. This
2188 * will eventually be serialized from above but at the moment isn't.
2191 static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
2193 if (tty_write_room(gsm->tty) < len) {
2194 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
2198 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET,
2200 gsm->tty->ops->write(gsm->tty, data, len);
2205 * gsmld_attach_gsm - mode set up
2206 * @tty: our tty structure
2209 * Set up the MUX for basic mode and commence connecting to the
2210 * modem. Currently called from the line discipline set up but
2211 * will need moving to an ioctl path.
2214 static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2217 int base = gsm->num << 6; /* Base for this MUX */
2219 gsm->tty = tty_kref_get(tty);
2220 gsm->output = gsmld_output;
2221 ret = gsm_activate_mux(gsm);
2223 tty_kref_put(gsm->tty);
2225 /* Don't register device 0 - this is the control channel and not
2226 a usable tty interface */
2227 for (i = 1; i < NUM_DLCI; i++)
2228 tty_register_device(gsm_tty_driver, base + i, NULL);
2235 * gsmld_detach_gsm - stop doing 0710 mux
2236 * @tty: tty attached to the mux
2239 * Shutdown and then clean up the resources used by the line discipline
2242 static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2245 int base = gsm->num << 6; /* Base for this MUX */
2247 WARN_ON(tty != gsm->tty);
2248 for (i = 1; i < NUM_DLCI; i++)
2249 tty_unregister_device(gsm_tty_driver, base + i);
2250 gsm_cleanup_mux(gsm);
2251 tty_kref_put(gsm->tty);
2255 static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
2256 char *fp, int count)
2258 struct gsm_mux *gsm = tty->disc_data;
2259 const unsigned char *dp;
2266 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET,
2269 for (i = count, dp = cp, f = fp; i; i--, dp++) {
2273 gsm->receive(gsm, *dp);
2279 gsm->error(gsm, *dp, flags);
2282 WARN_ONCE(1, "%s: unknown flag %d\n",
2283 tty_name(tty, buf), flags);
2287 /* FASYNC if needed ? */
2288 /* If clogged call tty_throttle(tty); */
2292 * gsmld_chars_in_buffer - report available bytes
2295 * Report the number of characters buffered to be delivered to user
2296 * at this instant in time.
2301 static ssize_t gsmld_chars_in_buffer(struct tty_struct *tty)
2307 * gsmld_flush_buffer - clean input queue
2308 * @tty: terminal device
2310 * Flush the input buffer. Called when the line discipline is
2311 * being closed, when the tty layer wants the buffer flushed (eg
2315 static void gsmld_flush_buffer(struct tty_struct *tty)
2320 * gsmld_close - close the ldisc for this tty
2323 * Called from the terminal layer when this line discipline is
2324 * being shut down, either because of a close or becsuse of a
2325 * discipline change. The function will not be called while other
2326 * ldisc methods are in progress.
2329 static void gsmld_close(struct tty_struct *tty)
2331 struct gsm_mux *gsm = tty->disc_data;
2333 gsmld_detach_gsm(tty, gsm);
2335 gsmld_flush_buffer(tty);
2336 /* Do other clean up here */
2341 * gsmld_open - open an ldisc
2342 * @tty: terminal to open
2344 * Called when this line discipline is being attached to the
2345 * terminal device. Can sleep. Called serialized so that no
2346 * other events will occur in parallel. No further open will occur
2350 static int gsmld_open(struct tty_struct *tty)
2352 struct gsm_mux *gsm;
2354 if (tty->ops->write == NULL)
2357 /* Attach our ldisc data */
2358 gsm = gsm_alloc_mux();
2362 tty->disc_data = gsm;
2363 tty->receive_room = 65536;
2365 /* Attach the initial passive connection */
2367 return gsmld_attach_gsm(tty, gsm);
2371 * gsmld_write_wakeup - asynchronous I/O notifier
2374 * Required for the ptys, serial driver etc. since processes
2375 * that attach themselves to the master and rely on ASYNC
2376 * IO must be woken up
2379 static void gsmld_write_wakeup(struct tty_struct *tty)
2381 struct gsm_mux *gsm = tty->disc_data;
2382 unsigned long flags;
2385 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2386 spin_lock_irqsave(&gsm->tx_lock, flags);
2388 if (gsm->tx_bytes < TX_THRESH_LO) {
2389 gsm_dlci_data_sweep(gsm);
2391 spin_unlock_irqrestore(&gsm->tx_lock, flags);
2395 * gsmld_read - read function for tty
2397 * @file: file object
2398 * @buf: userspace buffer pointer
2401 * Perform reads for the line discipline. We are guaranteed that the
2402 * line discipline will not be closed under us but we may get multiple
2403 * parallel readers and must handle this ourselves. We may also get
2404 * a hangup. Always called in user context, may sleep.
2406 * This code must be sure never to sleep through a hangup.
2409 static ssize_t gsmld_read(struct tty_struct *tty, struct file *file,
2410 unsigned char __user *buf, size_t nr)
2416 * gsmld_write - write function for tty
2418 * @file: file object
2419 * @buf: userspace buffer pointer
2422 * Called when the owner of the device wants to send a frame
2423 * itself (or some other control data). The data is transferred
2424 * as-is and must be properly framed and checksummed as appropriate
2425 * by userspace. Frames are either sent whole or not at all as this
2426 * avoids pain user side.
2429 static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
2430 const unsigned char *buf, size_t nr)
2432 int space = tty_write_room(tty);
2434 return tty->ops->write(tty, buf, nr);
2435 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2440 * gsmld_poll - poll method for N_GSM0710
2441 * @tty: terminal device
2442 * @file: file accessing it
2445 * Called when the line discipline is asked to poll() for data or
2446 * for special events. This code is not serialized with respect to
2447 * other events save open/close.
2449 * This code must be sure never to sleep through a hangup.
2450 * Called without the kernel lock held - fine
2453 static unsigned int gsmld_poll(struct tty_struct *tty, struct file *file,
2456 unsigned int mask = 0;
2457 struct gsm_mux *gsm = tty->disc_data;
2459 poll_wait(file, &tty->read_wait, wait);
2460 poll_wait(file, &tty->write_wait, wait);
2461 if (tty_hung_up_p(file))
2463 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
2464 mask |= POLLOUT | POLLWRNORM;
2470 static int gsmld_config(struct tty_struct *tty, struct gsm_mux *gsm,
2471 struct gsm_config *c)
2474 int need_restart = 0;
2476 /* Stuff we don't support yet - UI or I frame transport, windowing */
2477 if ((c->adaption != 1 && c->adaption != 2) || c->k)
2479 /* Check the MRU/MTU range looks sane */
2480 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8)
2484 if (c->encapsulation > 1) /* Basic, advanced, no I */
2486 if (c->initiator > 1)
2488 if (c->i == 0 || c->i > 2) /* UIH and UI only */
2491 * See what is needed for reconfiguration
2495 if (c->t1 != 0 && c->t1 != gsm->t1)
2497 if (c->t2 != 0 && c->t2 != gsm->t2)
2499 if (c->encapsulation != gsm->encoding)
2501 if (c->adaption != gsm->adaption)
2504 if (c->initiator != gsm->initiator)
2506 if (c->mru != gsm->mru)
2508 if (c->mtu != gsm->mtu)
2512 * Close down what is needed, restart and initiate the new
2516 if (need_close || need_restart) {
2517 gsm_dlci_begin_close(gsm->dlci[0]);
2518 /* This will timeout if the link is down due to N2 expiring */
2519 wait_event_interruptible(gsm->event,
2520 gsm->dlci[0]->state == DLCI_CLOSED);
2521 if (signal_pending(current))
2525 gsm_cleanup_mux(gsm);
2527 gsm->initiator = c->initiator;
2530 gsm->encoding = c->encapsulation;
2531 gsm->adaption = c->adaption;
2544 /* FIXME: We need to separate activation/deactivation from adding
2545 and removing from the mux array */
2547 gsm_activate_mux(gsm);
2548 if (gsm->initiator && need_close)
2549 gsm_dlci_begin_open(gsm->dlci[0]);
2553 static int gsmld_ioctl(struct tty_struct *tty, struct file *file,
2554 unsigned int cmd, unsigned long arg)
2556 struct gsm_config c;
2557 struct gsm_mux *gsm = tty->disc_data;
2560 case GSMIOC_GETCONF:
2561 memset(&c, 0, sizeof(c));
2562 c.adaption = gsm->adaption;
2563 c.encapsulation = gsm->encoding;
2564 c.initiator = gsm->initiator;
2567 c.t3 = 0; /* Not supported */
2569 if (gsm->ftype == UIH)
2573 pr_debug("Ftype %d i %d\n", gsm->ftype, c.i);
2577 if (copy_to_user((void *)arg, &c, sizeof(c)))
2580 case GSMIOC_SETCONF:
2581 if (copy_from_user(&c, (void *)arg, sizeof(c)))
2583 return gsmld_config(tty, gsm, &c);
2585 return n_tty_ioctl_helper(tty, file, cmd, arg);
2594 static int gsm_mux_net_open(struct net_device *net)
2596 pr_debug("%s called\n", __func__);
2597 netif_start_queue(net);
2601 static int gsm_mux_net_close(struct net_device *net)
2603 netif_stop_queue(net);
2607 static struct net_device_stats *gsm_mux_net_get_stats(struct net_device *net)
2609 return &((struct gsm_mux_net *)netdev_priv(net))->stats;
2611 static void dlci_net_free(struct gsm_dlci *dlci)
2617 dlci->adaption = dlci->prev_adaption;
2618 dlci->data = dlci->prev_data;
2619 free_netdev(dlci->net);
2622 static void net_free(struct kref *ref)
2624 struct gsm_mux_net *mux_net;
2625 struct gsm_dlci *dlci;
2627 mux_net = container_of(ref, struct gsm_mux_net, ref);
2628 dlci = mux_net->dlci;
2631 unregister_netdev(dlci->net);
2632 dlci_net_free(dlci);
2636 static inline void muxnet_get(struct gsm_mux_net *mux_net)
2638 kref_get(&mux_net->ref);
2641 static inline void muxnet_put(struct gsm_mux_net *mux_net)
2643 kref_put(&mux_net->ref, net_free);
2646 static int gsm_mux_net_start_xmit(struct sk_buff *skb,
2647 struct net_device *net)
2649 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
2650 struct gsm_dlci *dlci = mux_net->dlci;
2651 muxnet_get(mux_net);
2653 skb_queue_head(&dlci->skb_list, skb);
2654 STATS(net).tx_packets++;
2655 STATS(net).tx_bytes += skb->len;
2656 gsm_dlci_data_kick(dlci);
2657 /* And tell the kernel when the last transmit started. */
2658 net->trans_start = jiffies;
2659 muxnet_put(mux_net);
2660 return NETDEV_TX_OK;
2663 /* called when a packet did not ack after watchdogtimeout */
2664 static void gsm_mux_net_tx_timeout(struct net_device *net)
2666 /* Tell syslog we are hosed. */
2667 dev_dbg(&net->dev, "Tx timed out.\n");
2669 /* Update statistics */
2670 STATS(net).tx_errors++;
2673 static void gsm_mux_rx_netchar(struct gsm_dlci *dlci,
2674 unsigned char *in_buf, int size)
2676 struct net_device *net = dlci->net;
2677 struct sk_buff *skb;
2678 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
2679 muxnet_get(mux_net);
2681 /* Allocate an sk_buff */
2682 skb = dev_alloc_skb(size + NET_IP_ALIGN);
2684 /* We got no receive buffer. */
2685 STATS(net).rx_dropped++;
2686 muxnet_put(mux_net);
2689 skb_reserve(skb, NET_IP_ALIGN);
2690 memcpy(skb_put(skb, size), in_buf, size);
2693 skb->protocol = __constant_htons(ETH_P_IP);
2695 /* Ship it off to the kernel */
2698 /* update out statistics */
2699 STATS(net).rx_packets++;
2700 STATS(net).rx_bytes += size;
2701 muxnet_put(mux_net);
2705 int gsm_change_mtu(struct net_device *net, int new_mtu)
2707 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
2708 if ((new_mtu < 8) || (new_mtu > mux_net->dlci->gsm->mtu))
2714 static void gsm_mux_net_init(struct net_device *net)
2716 static const struct net_device_ops gsm_netdev_ops = {
2717 .ndo_open = gsm_mux_net_open,
2718 .ndo_stop = gsm_mux_net_close,
2719 .ndo_start_xmit = gsm_mux_net_start_xmit,
2720 .ndo_tx_timeout = gsm_mux_net_tx_timeout,
2721 .ndo_get_stats = gsm_mux_net_get_stats,
2722 .ndo_change_mtu = gsm_change_mtu,
2725 net->netdev_ops = &gsm_netdev_ops;
2727 /* fill in the other fields */
2728 net->watchdog_timeo = GSM_NET_TX_TIMEOUT;
2729 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
2730 net->type = ARPHRD_NONE;
2731 net->tx_queue_len = 10;
2735 /* caller holds the dlci mutex */
2736 static void gsm_destroy_network(struct gsm_dlci *dlci)
2738 struct gsm_mux_net *mux_net;
2740 pr_debug("destroy network interface");
2743 mux_net = (struct gsm_mux_net *)netdev_priv(dlci->net);
2744 muxnet_put(mux_net);
2748 /* caller holds the dlci mutex */
2749 static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
2753 struct net_device *net;
2754 struct gsm_mux_net *mux_net;
2756 if (!capable(CAP_NET_ADMIN))
2759 /* Already in a non tty mode */
2760 if (dlci->adaption > 2)
2763 if (nc->protocol != htons(ETH_P_IP))
2764 return -EPROTONOSUPPORT;
2766 if (nc->adaption != 3 && nc->adaption != 4)
2767 return -EPROTONOSUPPORT;
2769 pr_debug("create network interface");
2772 if (nc->if_name[0] != '\0')
2773 netname = nc->if_name;
2774 net = alloc_netdev(sizeof(struct gsm_mux_net),
2778 pr_err("alloc_netdev failed");
2781 net->mtu = dlci->gsm->mtu;
2782 mux_net = (struct gsm_mux_net *)netdev_priv(net);
2783 mux_net->dlci = dlci;
2784 kref_init(&mux_net->ref);
2785 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */
2787 /* reconfigure dlci for network */
2788 dlci->prev_adaption = dlci->adaption;
2789 dlci->prev_data = dlci->data;
2790 dlci->adaption = nc->adaption;
2791 dlci->data = gsm_mux_rx_netchar;
2794 pr_debug("register netdev");
2795 retval = register_netdev(net);
2797 pr_err("network register fail %d\n", retval);
2798 dlci_net_free(dlci);
2801 return net->ifindex; /* return network index */
2804 /* Line discipline for real tty */
2805 struct tty_ldisc_ops tty_ldisc_packet = {
2806 .owner = THIS_MODULE,
2807 .magic = TTY_LDISC_MAGIC,
2810 .close = gsmld_close,
2811 .flush_buffer = gsmld_flush_buffer,
2812 .chars_in_buffer = gsmld_chars_in_buffer,
2814 .write = gsmld_write,
2815 .ioctl = gsmld_ioctl,
2817 .receive_buf = gsmld_receive_buf,
2818 .write_wakeup = gsmld_write_wakeup
2827 static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk)
2830 struct gsm_control *ctrl;
2836 modembits[0] = len << 1 | EA; /* Data bytes */
2837 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */
2838 modembits[2] = gsm_encode_modem(dlci) << 1 | EA;
2840 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */
2841 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1);
2844 return gsm_control_wait(dlci->gsm, ctrl);
2847 static int gsm_carrier_raised(struct tty_port *port)
2849 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2850 /* Not yet open so no carrier info */
2851 if (dlci->state != DLCI_OPEN)
2855 return dlci->modem_rx & TIOCM_CD;
2858 static void gsm_dtr_rts(struct tty_port *port, int onoff)
2860 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2861 unsigned int modem_tx = dlci->modem_tx;
2863 modem_tx |= TIOCM_DTR | TIOCM_RTS;
2865 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
2866 if (modem_tx != dlci->modem_tx) {
2867 dlci->modem_tx = modem_tx;
2868 gsmtty_modem_update(dlci, 0);
2872 static const struct tty_port_operations gsm_port_ops = {
2873 .carrier_raised = gsm_carrier_raised,
2874 .dtr_rts = gsm_dtr_rts,
2875 .destruct = gsm_dlci_free,
2878 static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty)
2880 struct gsm_mux *gsm;
2881 struct gsm_dlci *dlci;
2882 unsigned int line = tty->index;
2883 unsigned int mux = line >> 6;
2891 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
2892 if (gsm_mux[mux] == NULL)
2894 if (line == 0 || line > 61) /* 62/63 reserved */
2899 /* If DLCI 0 is not yet fully open return an error. This is ok from a locking
2900 perspective as we don't have to worry about this if DLCI0 is lost */
2901 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN)
2903 dlci = gsm->dlci[line];
2906 dlci = gsm_dlci_alloc(gsm, line);
2910 ret = tty_port_install(&dlci->port, driver, tty);
2917 tty->driver_data = dlci;
2922 static int gsmtty_open(struct tty_struct *tty, struct file *filp)
2924 struct gsm_dlci *dlci = tty->driver_data;
2925 struct tty_port *port = &dlci->port;
2929 dlci_get(dlci->gsm->dlci[0]);
2931 tty_port_tty_set(port, tty);
2934 /* We could in theory open and close before we wait - eg if we get
2935 a DM straight back. This is ok as that will have caused a hangup */
2936 set_bit(ASYNCB_INITIALIZED, &port->flags);
2937 /* Start sending off SABM messages */
2938 gsm_dlci_begin_open(dlci);
2939 /* And wait for virtual carrier */
2940 return tty_port_block_til_ready(port, tty, filp);
2943 static void gsmtty_close(struct tty_struct *tty, struct file *filp)
2945 struct gsm_dlci *dlci = tty->driver_data;
2946 struct gsm_mux *gsm;
2950 mutex_lock(&dlci->mutex);
2951 gsm_destroy_network(dlci);
2952 mutex_unlock(&dlci->mutex);
2954 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
2956 gsm_dlci_begin_close(dlci);
2957 tty_port_close_end(&dlci->port, tty);
2958 tty_port_tty_set(&dlci->port, NULL);
2961 dlci_put(gsm->dlci[0]);
2965 static void gsmtty_hangup(struct tty_struct *tty)
2967 struct gsm_dlci *dlci = tty->driver_data;
2968 tty_port_hangup(&dlci->port);
2969 gsm_dlci_begin_close(dlci);
2972 static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf,
2975 struct gsm_dlci *dlci = tty->driver_data;
2976 /* Stuff the bytes into the fifo queue */
2977 int sent = kfifo_in_locked(dlci->fifo, buf, len, &dlci->lock);
2978 /* Need to kick the channel */
2979 gsm_dlci_data_kick(dlci);
2983 static int gsmtty_write_room(struct tty_struct *tty)
2985 struct gsm_dlci *dlci = tty->driver_data;
2986 return TX_SIZE - kfifo_len(dlci->fifo);
2989 static int gsmtty_chars_in_buffer(struct tty_struct *tty)
2991 struct gsm_dlci *dlci = tty->driver_data;
2992 return kfifo_len(dlci->fifo);
2995 static void gsmtty_flush_buffer(struct tty_struct *tty)
2997 struct gsm_dlci *dlci = tty->driver_data;
2998 /* Caution needed: If we implement reliable transport classes
2999 then the data being transmitted can't simply be junked once
3000 it has first hit the stack. Until then we can just blow it
3002 kfifo_reset(dlci->fifo);
3003 /* Need to unhook this DLCI from the transmit queue logic */
3006 static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
3008 /* The FIFO handles the queue so the kernel will do the right
3009 thing waiting on chars_in_buffer before calling us. No work
3013 static int gsmtty_tiocmget(struct tty_struct *tty)
3015 struct gsm_dlci *dlci = tty->driver_data;
3016 return dlci->modem_rx;
3019 static int gsmtty_tiocmset(struct tty_struct *tty,
3020 unsigned int set, unsigned int clear)
3022 struct gsm_dlci *dlci = tty->driver_data;
3023 unsigned int modem_tx = dlci->modem_tx;
3028 if (modem_tx != dlci->modem_tx) {
3029 dlci->modem_tx = modem_tx;
3030 return gsmtty_modem_update(dlci, 0);
3036 static int gsmtty_ioctl(struct tty_struct *tty,
3037 unsigned int cmd, unsigned long arg)
3039 struct gsm_dlci *dlci = tty->driver_data;
3040 struct gsm_netconfig nc;
3044 case GSMIOC_ENABLE_NET:
3045 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc)))
3047 nc.if_name[IFNAMSIZ-1] = '\0';
3048 /* return net interface index or error code */
3049 mutex_lock(&dlci->mutex);
3050 index = gsm_create_network(dlci, &nc);
3051 mutex_unlock(&dlci->mutex);
3052 if (copy_to_user((void __user *)arg, &nc, sizeof(nc)))
3055 case GSMIOC_DISABLE_NET:
3056 if (!capable(CAP_NET_ADMIN))
3058 mutex_lock(&dlci->mutex);
3059 gsm_destroy_network(dlci);
3060 mutex_unlock(&dlci->mutex);
3063 return -ENOIOCTLCMD;
3067 static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old)
3069 /* For the moment its fixed. In actual fact the speed information
3070 for the virtual channel can be propogated in both directions by
3071 the RPN control message. This however rapidly gets nasty as we
3072 then have to remap modem signals each way according to whether
3073 our virtual cable is null modem etc .. */
3074 tty_termios_copy_hw(&tty->termios, old);
3077 static void gsmtty_throttle(struct tty_struct *tty)
3079 struct gsm_dlci *dlci = tty->driver_data;
3080 if (tty->termios.c_cflag & CRTSCTS)
3081 dlci->modem_tx &= ~TIOCM_DTR;
3082 dlci->throttled = 1;
3083 /* Send an MSC with DTR cleared */
3084 gsmtty_modem_update(dlci, 0);
3087 static void gsmtty_unthrottle(struct tty_struct *tty)
3089 struct gsm_dlci *dlci = tty->driver_data;
3090 if (tty->termios.c_cflag & CRTSCTS)
3091 dlci->modem_tx |= TIOCM_DTR;
3092 dlci->throttled = 0;
3093 /* Send an MSC with DTR set */
3094 gsmtty_modem_update(dlci, 0);
3097 static int gsmtty_break_ctl(struct tty_struct *tty, int state)
3099 struct gsm_dlci *dlci = tty->driver_data;
3100 int encode = 0; /* Off */
3102 if (state == -1) /* "On indefinitely" - we can't encode this
3105 else if (state > 0) {
3106 encode = state / 200; /* mS to encoding */
3108 encode = 0x0F; /* Best effort */
3110 return gsmtty_modem_update(dlci, encode);
3114 /* Virtual ttys for the demux */
3115 static const struct tty_operations gsmtty_ops = {
3116 .install = gsmtty_install,
3117 .open = gsmtty_open,
3118 .close = gsmtty_close,
3119 .write = gsmtty_write,
3120 .write_room = gsmtty_write_room,
3121 .chars_in_buffer = gsmtty_chars_in_buffer,
3122 .flush_buffer = gsmtty_flush_buffer,
3123 .ioctl = gsmtty_ioctl,
3124 .throttle = gsmtty_throttle,
3125 .unthrottle = gsmtty_unthrottle,
3126 .set_termios = gsmtty_set_termios,
3127 .hangup = gsmtty_hangup,
3128 .wait_until_sent = gsmtty_wait_until_sent,
3129 .tiocmget = gsmtty_tiocmget,
3130 .tiocmset = gsmtty_tiocmset,
3131 .break_ctl = gsmtty_break_ctl,
3136 static int __init gsm_init(void)
3138 /* Fill in our line protocol discipline, and register it */
3139 int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet);
3141 pr_err("n_gsm: can't register line discipline (err = %d)\n",
3146 gsm_tty_driver = alloc_tty_driver(256);
3147 if (!gsm_tty_driver) {
3148 tty_unregister_ldisc(N_GSM0710);
3149 pr_err("gsm_init: tty allocation failed.\n");
3152 gsm_tty_driver->driver_name = "gsmtty";
3153 gsm_tty_driver->name = "gsmtty";
3154 gsm_tty_driver->major = 0; /* Dynamic */
3155 gsm_tty_driver->minor_start = 0;
3156 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
3157 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
3158 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV
3159 | TTY_DRIVER_HARDWARE_BREAK;
3160 gsm_tty_driver->init_termios = tty_std_termios;
3162 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
3163 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
3165 spin_lock_init(&gsm_mux_lock);
3167 if (tty_register_driver(gsm_tty_driver)) {
3168 put_tty_driver(gsm_tty_driver);
3169 tty_unregister_ldisc(N_GSM0710);
3170 pr_err("gsm_init: tty registration failed.\n");
3173 pr_debug("gsm_init: loaded as %d,%d.\n",
3174 gsm_tty_driver->major, gsm_tty_driver->minor_start);
3178 static void __exit gsm_exit(void)
3180 int status = tty_unregister_ldisc(N_GSM0710);
3182 pr_err("n_gsm: can't unregister line discipline (err = %d)\n",
3184 tty_unregister_driver(gsm_tty_driver);
3185 put_tty_driver(gsm_tty_driver);
3188 module_init(gsm_init);
3189 module_exit(gsm_exit);
3192 MODULE_LICENSE("GPL");
3193 MODULE_ALIAS_LDISC(N_GSM0710);