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))
1072 tty_insert_flip_char(&dlci->port, 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_port *port;
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)
1164 port = &gsm->dlci[addr]->port;
1167 tty_insert_flip_char(port, 0, TTY_OVERRUN);
1169 tty_insert_flip_char(port, 0, TTY_PARITY);
1171 tty_insert_flip_char(port, 0, TTY_FRAME);
1173 tty_flip_buffer_push(port);
1175 gsm_control_reply(gsm, CMD_RLS, data, clen);
1178 static void gsm_dlci_begin_close(struct gsm_dlci *dlci);
1181 * gsm_control_message - DLCI 0 control processing
1183 * @command: the command EA
1184 * @data: data beyond the command/length EAs
1187 * Input processor for control messages from the other end of the link.
1188 * Processes the incoming request and queues a response frame or an
1189 * NSC response if not supported
1192 static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
1196 unsigned long flags;
1200 struct gsm_dlci *dlci = gsm->dlci[0];
1201 /* Modem wishes to close down */
1205 gsm_dlci_begin_close(dlci);
1210 /* Modem wishes to test, reply with the data */
1211 gsm_control_reply(gsm, CMD_TEST, data, clen);
1214 /* Modem can accept data again */
1215 gsm->constipated = 0;
1216 gsm_control_reply(gsm, CMD_FCON, NULL, 0);
1217 /* Kick the link in case it is idling */
1218 spin_lock_irqsave(&gsm->tx_lock, flags);
1220 spin_unlock_irqrestore(&gsm->tx_lock, flags);
1223 /* Modem wants us to STFU */
1224 gsm->constipated = 1;
1225 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0);
1228 /* Out of band modem line change indicator for a DLCI */
1229 gsm_control_modem(gsm, data, clen);
1232 /* Out of band error reception for a DLCI */
1233 gsm_control_rls(gsm, data, clen);
1236 /* Modem wishes to enter power saving state */
1237 gsm_control_reply(gsm, CMD_PSC, NULL, 0);
1239 /* Optional unsupported commands */
1240 case CMD_PN: /* Parameter negotiation */
1241 case CMD_RPN: /* Remote port negotiation */
1242 case CMD_SNC: /* Service negotiation command */
1244 /* Reply to bad commands with an NSC */
1246 gsm_control_reply(gsm, CMD_NSC, buf, 1);
1252 * gsm_control_response - process a response to our control
1254 * @command: the command (response) EA
1255 * @data: data beyond the command/length EA
1258 * Process a response to an outstanding command. We only allow a single
1259 * control message in flight so this is fairly easy. All the clean up
1260 * is done by the caller, we just update the fields, flag it as done
1264 static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
1267 struct gsm_control *ctrl;
1268 unsigned long flags;
1270 spin_lock_irqsave(&gsm->control_lock, flags);
1272 ctrl = gsm->pending_cmd;
1273 /* Does the reply match our command */
1275 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) {
1276 /* Our command was replied to, kill the retry timer */
1277 del_timer(&gsm->t2_timer);
1278 gsm->pending_cmd = NULL;
1279 /* Rejected by the other end */
1280 if (command == CMD_NSC)
1281 ctrl->error = -EOPNOTSUPP;
1283 wake_up(&gsm->event);
1285 spin_unlock_irqrestore(&gsm->control_lock, flags);
1289 * gsm_control_transmit - send control packet
1291 * @ctrl: frame to send
1293 * Send out a pending control command (called under control lock)
1296 static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl)
1298 struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, gsm->ftype);
1301 msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */
1302 memcpy(msg->data + 1, ctrl->data, ctrl->len);
1303 gsm_data_queue(gsm->dlci[0], msg);
1307 * gsm_control_retransmit - retransmit a control frame
1308 * @data: pointer to our gsm object
1310 * Called off the T2 timer expiry in order to retransmit control frames
1311 * that have been lost in the system somewhere. The control_lock protects
1312 * us from colliding with another sender or a receive completion event.
1313 * In that situation the timer may still occur in a small window but
1314 * gsm->pending_cmd will be NULL and we just let the timer expire.
1317 static void gsm_control_retransmit(unsigned long data)
1319 struct gsm_mux *gsm = (struct gsm_mux *)data;
1320 struct gsm_control *ctrl;
1321 unsigned long flags;
1322 spin_lock_irqsave(&gsm->control_lock, flags);
1323 ctrl = gsm->pending_cmd;
1326 if (gsm->cretries == 0) {
1327 gsm->pending_cmd = NULL;
1328 ctrl->error = -ETIMEDOUT;
1330 spin_unlock_irqrestore(&gsm->control_lock, flags);
1331 wake_up(&gsm->event);
1334 gsm_control_transmit(gsm, ctrl);
1335 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1337 spin_unlock_irqrestore(&gsm->control_lock, flags);
1341 * gsm_control_send - send a control frame on DLCI 0
1342 * @gsm: the GSM channel
1343 * @command: command to send including CR bit
1344 * @data: bytes of data (must be kmalloced)
1345 * @len: length of the block to send
1347 * Queue and dispatch a control command. Only one command can be
1348 * active at a time. In theory more can be outstanding but the matching
1349 * gets really complicated so for now stick to one outstanding.
1352 static struct gsm_control *gsm_control_send(struct gsm_mux *gsm,
1353 unsigned int command, u8 *data, int clen)
1355 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control),
1357 unsigned long flags;
1361 wait_event(gsm->event, gsm->pending_cmd == NULL);
1362 spin_lock_irqsave(&gsm->control_lock, flags);
1363 if (gsm->pending_cmd != NULL) {
1364 spin_unlock_irqrestore(&gsm->control_lock, flags);
1367 ctrl->cmd = command;
1370 gsm->pending_cmd = ctrl;
1371 gsm->cretries = gsm->n2;
1372 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1373 gsm_control_transmit(gsm, ctrl);
1374 spin_unlock_irqrestore(&gsm->control_lock, flags);
1379 * gsm_control_wait - wait for a control to finish
1381 * @control: control we are waiting on
1383 * Waits for the control to complete or time out. Frees any used
1384 * resources and returns 0 for success, or an error if the remote
1385 * rejected or ignored the request.
1388 static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
1391 wait_event(gsm->event, control->done == 1);
1392 err = control->error;
1399 * DLCI level handling: Needs krefs
1403 * State transitions and timers
1407 * gsm_dlci_close - a DLCI has closed
1408 * @dlci: DLCI that closed
1410 * Perform processing when moving a DLCI into closed state. If there
1411 * is an attached tty this is hung up
1414 static void gsm_dlci_close(struct gsm_dlci *dlci)
1416 del_timer(&dlci->t1);
1418 pr_debug("DLCI %d goes closed.\n", dlci->addr);
1419 dlci->state = DLCI_CLOSED;
1420 if (dlci->addr != 0) {
1421 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1426 kfifo_reset(dlci->fifo);
1428 dlci->gsm->dead = 1;
1429 wake_up(&dlci->gsm->event);
1430 /* A DLCI 0 close is a MUX termination so we need to kick that
1431 back to userspace somehow */
1435 * gsm_dlci_open - a DLCI has opened
1436 * @dlci: DLCI that opened
1438 * Perform processing when moving a DLCI into open state.
1441 static void gsm_dlci_open(struct gsm_dlci *dlci)
1443 /* Note that SABM UA .. SABM UA first UA lost can mean that we go
1445 del_timer(&dlci->t1);
1446 /* This will let a tty open continue */
1447 dlci->state = DLCI_OPEN;
1449 pr_debug("DLCI %d goes open.\n", dlci->addr);
1450 wake_up(&dlci->gsm->event);
1454 * gsm_dlci_t1 - T1 timer expiry
1455 * @dlci: DLCI that opened
1457 * The T1 timer handles retransmits of control frames (essentially of
1458 * SABM and DISC). We resend the command until the retry count runs out
1459 * in which case an opening port goes back to closed and a closing port
1460 * is simply put into closed state (any further frames from the other
1461 * end will get a DM response)
1464 static void gsm_dlci_t1(unsigned long data)
1466 struct gsm_dlci *dlci = (struct gsm_dlci *)data;
1467 struct gsm_mux *gsm = dlci->gsm;
1469 switch (dlci->state) {
1472 if (dlci->retries) {
1473 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1474 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1476 gsm_dlci_close(dlci);
1480 if (dlci->retries) {
1481 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1482 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1484 gsm_dlci_close(dlci);
1490 * gsm_dlci_begin_open - start channel open procedure
1491 * @dlci: DLCI to open
1493 * Commence opening a DLCI from the Linux side. We issue SABM messages
1494 * to the modem which should then reply with a UA, at which point we
1495 * will move into open state. Opening is done asynchronously with retry
1496 * running off timers and the responses.
1499 static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
1501 struct gsm_mux *gsm = dlci->gsm;
1502 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING)
1504 dlci->retries = gsm->n2;
1505 dlci->state = DLCI_OPENING;
1506 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1507 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1511 * gsm_dlci_begin_close - start channel open procedure
1512 * @dlci: DLCI to open
1514 * Commence closing a DLCI from the Linux side. We issue DISC messages
1515 * to the modem which should then reply with a UA, at which point we
1516 * will move into closed state. Closing is done asynchronously with retry
1517 * off timers. We may also receive a DM reply from the other end which
1518 * indicates the channel was already closed.
1521 static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
1523 struct gsm_mux *gsm = dlci->gsm;
1524 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
1526 dlci->retries = gsm->n2;
1527 dlci->state = DLCI_CLOSING;
1528 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1529 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1533 * gsm_dlci_data - data arrived
1535 * @data: block of bytes received
1536 * @len: length of received block
1538 * A UI or UIH frame has arrived which contains data for a channel
1539 * other than the control channel. If the relevant virtual tty is
1540 * open we shovel the bits down it, if not we drop them.
1543 static void gsm_dlci_data(struct gsm_dlci *dlci, u8 *data, int clen)
1546 struct tty_port *port = &dlci->port;
1547 struct tty_struct *tty;
1548 unsigned int modem = 0;
1552 pr_debug("%d bytes for tty\n", len);
1553 switch (dlci->adaption) {
1554 /* Unsupported types */
1555 /* Packetised interruptible data */
1558 /* Packetised uininterruptible voice/data */
1561 /* Asynchronous serial with line state in each frame */
1563 while (gsm_read_ea(&modem, *data++) == 0) {
1568 tty = tty_port_tty_get(port);
1570 gsm_process_modem(tty, dlci, modem, clen);
1573 /* Line state will go via DLCI 0 controls only */
1576 tty_insert_flip_string(port, data, len);
1577 tty_flip_buffer_push(port);
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);
1692 static void gsm_destroy_network(struct gsm_dlci *dlci);
1695 * gsm_dlci_release - release DLCI
1696 * @dlci: DLCI to destroy
1698 * Release a DLCI. Actual free is deferred until either
1699 * mux is closed or tty is closed - whichever is last.
1703 static void gsm_dlci_release(struct gsm_dlci *dlci)
1705 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1707 mutex_lock(&dlci->mutex);
1708 gsm_destroy_network(dlci);
1709 mutex_unlock(&dlci->mutex);
1711 /* tty_vhangup needs the tty_lock, so unlock and
1712 relock after doing the hangup. */
1716 tty_port_tty_set(&dlci->port, NULL);
1719 dlci->state = DLCI_CLOSED;
1724 * LAPBish link layer logic
1728 * gsm_queue - a GSM frame is ready to process
1729 * @gsm: pointer to our gsm mux
1731 * At this point in time a frame has arrived and been demangled from
1732 * the line encoding. All the differences between the encodings have
1733 * been handled below us and the frame is unpacked into the structures.
1734 * The fcs holds the header FCS but any data FCS must be added here.
1737 static void gsm_queue(struct gsm_mux *gsm)
1739 struct gsm_dlci *dlci;
1742 /* We have to sneak a look at the packet body to do the FCS.
1743 A somewhat layering violation in the spec */
1745 if ((gsm->control & ~PF) == UI)
1746 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len);
1747 if (gsm->encoding == 0){
1748 /* WARNING: gsm->received_fcs is used for gsm->encoding = 0 only.
1749 In this case it contain the last piece of data
1750 required to generate final CRC */
1751 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs);
1753 if (gsm->fcs != GOOD_FCS) {
1756 pr_debug("BAD FCS %02x\n", gsm->fcs);
1759 address = gsm->address >> 1;
1760 if (address >= NUM_DLCI)
1763 cr = gsm->address & 1; /* C/R bit */
1765 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
1767 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */
1768 dlci = gsm->dlci[address];
1770 switch (gsm->control) {
1775 dlci = gsm_dlci_alloc(gsm, address);
1779 gsm_response(gsm, address, DM);
1781 gsm_response(gsm, address, UA);
1782 gsm_dlci_open(dlci);
1788 if (dlci == NULL || dlci->state == DLCI_CLOSED) {
1789 gsm_response(gsm, address, DM);
1792 /* Real close complete */
1793 gsm_response(gsm, address, UA);
1794 gsm_dlci_close(dlci);
1798 if (cr == 0 || dlci == NULL)
1800 switch (dlci->state) {
1802 gsm_dlci_close(dlci);
1805 gsm_dlci_open(dlci);
1809 case DM: /* DM can be valid unsolicited */
1815 gsm_dlci_close(dlci);
1825 if (dlci == NULL || dlci->state != DLCI_OPEN) {
1826 gsm_command(gsm, address, DM|PF);
1829 dlci->data(dlci, gsm->buf, gsm->len);
1842 * gsm0_receive - perform processing for non-transparency
1843 * @gsm: gsm data for this ldisc instance
1846 * Receive bytes in gsm mode 0
1849 static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
1853 switch (gsm->state) {
1854 case GSM_SEARCH: /* SOF marker */
1855 if (c == GSM0_SOF) {
1856 gsm->state = GSM_ADDRESS;
1859 gsm->fcs = INIT_FCS;
1862 case GSM_ADDRESS: /* Address EA */
1863 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1864 if (gsm_read_ea(&gsm->address, c))
1865 gsm->state = GSM_CONTROL;
1867 case GSM_CONTROL: /* Control Byte */
1868 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1870 gsm->state = GSM_LEN0;
1872 case GSM_LEN0: /* Length EA */
1873 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1874 if (gsm_read_ea(&gsm->len, c)) {
1875 if (gsm->len > gsm->mru) {
1877 gsm->state = GSM_SEARCH;
1882 gsm->state = GSM_FCS;
1884 gsm->state = GSM_DATA;
1887 gsm->state = GSM_LEN1;
1890 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1892 gsm->len |= len << 7;
1893 if (gsm->len > gsm->mru) {
1895 gsm->state = GSM_SEARCH;
1900 gsm->state = GSM_FCS;
1902 gsm->state = GSM_DATA;
1904 case GSM_DATA: /* Data */
1905 gsm->buf[gsm->count++] = c;
1906 if (gsm->count == gsm->len)
1907 gsm->state = GSM_FCS;
1909 case GSM_FCS: /* FCS follows the packet */
1910 gsm->received_fcs = c;
1912 gsm->state = GSM_SSOF;
1915 if (c == GSM0_SOF) {
1916 gsm->state = GSM_SEARCH;
1924 * gsm1_receive - perform processing for non-transparency
1925 * @gsm: gsm data for this ldisc instance
1928 * Receive bytes in mode 1 (Advanced option)
1931 static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
1933 if (c == GSM1_SOF) {
1934 /* EOF is only valid in frame if we have got to the data state
1935 and received at least one byte (the FCS) */
1936 if (gsm->state == GSM_DATA && gsm->count) {
1937 /* Extract the FCS */
1939 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
1940 gsm->len = gsm->count;
1942 gsm->state = GSM_START;
1945 /* Any partial frame was a runt so go back to start */
1946 if (gsm->state != GSM_START) {
1948 gsm->state = GSM_START;
1950 /* A SOF in GSM_START means we are still reading idling or
1955 if (c == GSM1_ESCAPE) {
1960 /* Only an unescaped SOF gets us out of GSM search */
1961 if (gsm->state == GSM_SEARCH)
1965 c ^= GSM1_ESCAPE_BITS;
1968 switch (gsm->state) {
1969 case GSM_START: /* First byte after SOF */
1971 gsm->state = GSM_ADDRESS;
1972 gsm->fcs = INIT_FCS;
1974 case GSM_ADDRESS: /* Address continuation */
1975 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1976 if (gsm_read_ea(&gsm->address, c))
1977 gsm->state = GSM_CONTROL;
1979 case GSM_CONTROL: /* Control Byte */
1980 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1983 gsm->state = GSM_DATA;
1985 case GSM_DATA: /* Data */
1986 if (gsm->count > gsm->mru) { /* Allow one for the FCS */
1987 gsm->state = GSM_OVERRUN;
1990 gsm->buf[gsm->count++] = c;
1992 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */
1998 * gsm_error - handle tty error
2000 * @data: byte received (may be invalid)
2001 * @flag: error received
2003 * Handle an error in the receipt of data for a frame. Currently we just
2004 * go back to hunting for a SOF.
2006 * FIXME: better diagnostics ?
2009 static void gsm_error(struct gsm_mux *gsm,
2010 unsigned char data, unsigned char flag)
2012 gsm->state = GSM_SEARCH;
2017 * gsm_cleanup_mux - generic GSM protocol cleanup
2020 * Clean up the bits of the mux which are the same for all framing
2021 * protocols. Remove the mux from the mux table, stop all the timers
2022 * and then shut down each device hanging up the channels as we go.
2025 void gsm_cleanup_mux(struct gsm_mux *gsm)
2028 struct gsm_dlci *dlci = gsm->dlci[0];
2029 struct gsm_msg *txq, *ntxq;
2030 struct gsm_control *gc;
2034 spin_lock(&gsm_mux_lock);
2035 for (i = 0; i < MAX_MUX; i++) {
2036 if (gsm_mux[i] == gsm) {
2041 spin_unlock(&gsm_mux_lock);
2042 WARN_ON(i == MAX_MUX);
2044 /* In theory disconnecting DLCI 0 is sufficient but for some
2045 modems this is apparently not the case. */
2047 gc = gsm_control_send(gsm, CMD_CLD, NULL, 0);
2049 gsm_control_wait(gsm, gc);
2051 del_timer_sync(&gsm->t2_timer);
2052 /* Now we are sure T2 has stopped */
2055 gsm_dlci_begin_close(dlci);
2056 wait_event_interruptible(gsm->event,
2057 dlci->state == DLCI_CLOSED);
2059 /* Free up any link layer users */
2060 for (i = 0; i < NUM_DLCI; i++)
2062 gsm_dlci_release(gsm->dlci[i]);
2063 /* Now wipe the queues */
2064 list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list)
2066 INIT_LIST_HEAD(&gsm->tx_list);
2068 EXPORT_SYMBOL_GPL(gsm_cleanup_mux);
2071 * gsm_activate_mux - generic GSM setup
2074 * Set up the bits of the mux which are the same for all framing
2075 * protocols. Add the mux to the mux table so it can be opened and
2076 * finally kick off connecting to DLCI 0 on the modem.
2079 int gsm_activate_mux(struct gsm_mux *gsm)
2081 struct gsm_dlci *dlci;
2084 init_timer(&gsm->t2_timer);
2085 gsm->t2_timer.function = gsm_control_retransmit;
2086 gsm->t2_timer.data = (unsigned long)gsm;
2087 init_waitqueue_head(&gsm->event);
2088 spin_lock_init(&gsm->control_lock);
2089 spin_lock_init(&gsm->tx_lock);
2091 if (gsm->encoding == 0)
2092 gsm->receive = gsm0_receive;
2094 gsm->receive = gsm1_receive;
2095 gsm->error = gsm_error;
2097 spin_lock(&gsm_mux_lock);
2098 for (i = 0; i < MAX_MUX; i++) {
2099 if (gsm_mux[i] == NULL) {
2105 spin_unlock(&gsm_mux_lock);
2109 dlci = gsm_dlci_alloc(gsm, 0);
2112 gsm->dead = 0; /* Tty opens are now permissible */
2115 EXPORT_SYMBOL_GPL(gsm_activate_mux);
2118 * gsm_free_mux - free up a mux
2121 * Dispose of allocated resources for a dead mux
2123 void gsm_free_mux(struct gsm_mux *gsm)
2125 kfree(gsm->txframe);
2129 EXPORT_SYMBOL_GPL(gsm_free_mux);
2132 * gsm_free_muxr - free up a mux
2135 * Dispose of allocated resources for a dead mux
2137 static void gsm_free_muxr(struct kref *ref)
2139 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref);
2143 static inline void mux_get(struct gsm_mux *gsm)
2145 kref_get(&gsm->ref);
2148 static inline void mux_put(struct gsm_mux *gsm)
2150 kref_put(&gsm->ref, gsm_free_muxr);
2154 * gsm_alloc_mux - allocate a mux
2156 * Creates a new mux ready for activation.
2159 struct gsm_mux *gsm_alloc_mux(void)
2161 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
2164 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL);
2165 if (gsm->buf == NULL) {
2169 gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL);
2170 if (gsm->txframe == NULL) {
2175 spin_lock_init(&gsm->lock);
2176 kref_init(&gsm->ref);
2177 INIT_LIST_HEAD(&gsm->tx_list);
2185 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
2187 gsm->dead = 1; /* Avoid early tty opens */
2191 EXPORT_SYMBOL_GPL(gsm_alloc_mux);
2194 * gsmld_output - write to link
2196 * @data: bytes to output
2199 * Write a block of data from the GSM mux to the data channel. This
2200 * will eventually be serialized from above but at the moment isn't.
2203 static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
2205 if (tty_write_room(gsm->tty) < len) {
2206 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
2210 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET,
2212 gsm->tty->ops->write(gsm->tty, data, len);
2217 * gsmld_attach_gsm - mode set up
2218 * @tty: our tty structure
2221 * Set up the MUX for basic mode and commence connecting to the
2222 * modem. Currently called from the line discipline set up but
2223 * will need moving to an ioctl path.
2226 static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2229 int base = gsm->num << 6; /* Base for this MUX */
2231 gsm->tty = tty_kref_get(tty);
2232 gsm->output = gsmld_output;
2233 ret = gsm_activate_mux(gsm);
2235 tty_kref_put(gsm->tty);
2237 /* Don't register device 0 - this is the control channel and not
2238 a usable tty interface */
2239 for (i = 1; i < NUM_DLCI; i++)
2240 tty_register_device(gsm_tty_driver, base + i, NULL);
2247 * gsmld_detach_gsm - stop doing 0710 mux
2248 * @tty: tty attached to the mux
2251 * Shutdown and then clean up the resources used by the line discipline
2254 static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2257 int base = gsm->num << 6; /* Base for this MUX */
2259 WARN_ON(tty != gsm->tty);
2260 for (i = 1; i < NUM_DLCI; i++)
2261 tty_unregister_device(gsm_tty_driver, base + i);
2262 gsm_cleanup_mux(gsm);
2263 tty_kref_put(gsm->tty);
2267 static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
2268 char *fp, int count)
2270 struct gsm_mux *gsm = tty->disc_data;
2271 const unsigned char *dp;
2278 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET,
2281 for (i = count, dp = cp, f = fp; i; i--, dp++) {
2285 gsm->receive(gsm, *dp);
2291 gsm->error(gsm, *dp, flags);
2294 WARN_ONCE(1, "%s: unknown flag %d\n",
2295 tty_name(tty, buf), flags);
2299 /* FASYNC if needed ? */
2300 /* If clogged call tty_throttle(tty); */
2304 * gsmld_chars_in_buffer - report available bytes
2307 * Report the number of characters buffered to be delivered to user
2308 * at this instant in time.
2313 static ssize_t gsmld_chars_in_buffer(struct tty_struct *tty)
2319 * gsmld_flush_buffer - clean input queue
2320 * @tty: terminal device
2322 * Flush the input buffer. Called when the line discipline is
2323 * being closed, when the tty layer wants the buffer flushed (eg
2327 static void gsmld_flush_buffer(struct tty_struct *tty)
2332 * gsmld_close - close the ldisc for this tty
2335 * Called from the terminal layer when this line discipline is
2336 * being shut down, either because of a close or becsuse of a
2337 * discipline change. The function will not be called while other
2338 * ldisc methods are in progress.
2341 static void gsmld_close(struct tty_struct *tty)
2343 struct gsm_mux *gsm = tty->disc_data;
2345 gsmld_detach_gsm(tty, gsm);
2347 gsmld_flush_buffer(tty);
2348 /* Do other clean up here */
2353 * gsmld_open - open an ldisc
2354 * @tty: terminal to open
2356 * Called when this line discipline is being attached to the
2357 * terminal device. Can sleep. Called serialized so that no
2358 * other events will occur in parallel. No further open will occur
2362 static int gsmld_open(struct tty_struct *tty)
2364 struct gsm_mux *gsm;
2366 if (tty->ops->write == NULL)
2369 /* Attach our ldisc data */
2370 gsm = gsm_alloc_mux();
2374 tty->disc_data = gsm;
2375 tty->receive_room = 65536;
2377 /* Attach the initial passive connection */
2379 return gsmld_attach_gsm(tty, gsm);
2383 * gsmld_write_wakeup - asynchronous I/O notifier
2386 * Required for the ptys, serial driver etc. since processes
2387 * that attach themselves to the master and rely on ASYNC
2388 * IO must be woken up
2391 static void gsmld_write_wakeup(struct tty_struct *tty)
2393 struct gsm_mux *gsm = tty->disc_data;
2394 unsigned long flags;
2397 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2398 spin_lock_irqsave(&gsm->tx_lock, flags);
2400 if (gsm->tx_bytes < TX_THRESH_LO) {
2401 gsm_dlci_data_sweep(gsm);
2403 spin_unlock_irqrestore(&gsm->tx_lock, flags);
2407 * gsmld_read - read function for tty
2409 * @file: file object
2410 * @buf: userspace buffer pointer
2413 * Perform reads for the line discipline. We are guaranteed that the
2414 * line discipline will not be closed under us but we may get multiple
2415 * parallel readers and must handle this ourselves. We may also get
2416 * a hangup. Always called in user context, may sleep.
2418 * This code must be sure never to sleep through a hangup.
2421 static ssize_t gsmld_read(struct tty_struct *tty, struct file *file,
2422 unsigned char __user *buf, size_t nr)
2428 * gsmld_write - write function for tty
2430 * @file: file object
2431 * @buf: userspace buffer pointer
2434 * Called when the owner of the device wants to send a frame
2435 * itself (or some other control data). The data is transferred
2436 * as-is and must be properly framed and checksummed as appropriate
2437 * by userspace. Frames are either sent whole or not at all as this
2438 * avoids pain user side.
2441 static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
2442 const unsigned char *buf, size_t nr)
2444 int space = tty_write_room(tty);
2446 return tty->ops->write(tty, buf, nr);
2447 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2452 * gsmld_poll - poll method for N_GSM0710
2453 * @tty: terminal device
2454 * @file: file accessing it
2457 * Called when the line discipline is asked to poll() for data or
2458 * for special events. This code is not serialized with respect to
2459 * other events save open/close.
2461 * This code must be sure never to sleep through a hangup.
2462 * Called without the kernel lock held - fine
2465 static unsigned int gsmld_poll(struct tty_struct *tty, struct file *file,
2468 unsigned int mask = 0;
2469 struct gsm_mux *gsm = tty->disc_data;
2471 poll_wait(file, &tty->read_wait, wait);
2472 poll_wait(file, &tty->write_wait, wait);
2473 if (tty_hung_up_p(file))
2475 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
2476 mask |= POLLOUT | POLLWRNORM;
2482 static int gsmld_config(struct tty_struct *tty, struct gsm_mux *gsm,
2483 struct gsm_config *c)
2486 int need_restart = 0;
2488 /* Stuff we don't support yet - UI or I frame transport, windowing */
2489 if ((c->adaption != 1 && c->adaption != 2) || c->k)
2491 /* Check the MRU/MTU range looks sane */
2492 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8)
2496 if (c->encapsulation > 1) /* Basic, advanced, no I */
2498 if (c->initiator > 1)
2500 if (c->i == 0 || c->i > 2) /* UIH and UI only */
2503 * See what is needed for reconfiguration
2507 if (c->t1 != 0 && c->t1 != gsm->t1)
2509 if (c->t2 != 0 && c->t2 != gsm->t2)
2511 if (c->encapsulation != gsm->encoding)
2513 if (c->adaption != gsm->adaption)
2516 if (c->initiator != gsm->initiator)
2518 if (c->mru != gsm->mru)
2520 if (c->mtu != gsm->mtu)
2524 * Close down what is needed, restart and initiate the new
2528 if (need_close || need_restart) {
2529 gsm_dlci_begin_close(gsm->dlci[0]);
2530 /* This will timeout if the link is down due to N2 expiring */
2531 wait_event_interruptible(gsm->event,
2532 gsm->dlci[0]->state == DLCI_CLOSED);
2533 if (signal_pending(current))
2537 gsm_cleanup_mux(gsm);
2539 gsm->initiator = c->initiator;
2542 gsm->encoding = c->encapsulation;
2543 gsm->adaption = c->adaption;
2556 /* FIXME: We need to separate activation/deactivation from adding
2557 and removing from the mux array */
2559 gsm_activate_mux(gsm);
2560 if (gsm->initiator && need_close)
2561 gsm_dlci_begin_open(gsm->dlci[0]);
2565 static int gsmld_ioctl(struct tty_struct *tty, struct file *file,
2566 unsigned int cmd, unsigned long arg)
2568 struct gsm_config c;
2569 struct gsm_mux *gsm = tty->disc_data;
2572 case GSMIOC_GETCONF:
2573 memset(&c, 0, sizeof(c));
2574 c.adaption = gsm->adaption;
2575 c.encapsulation = gsm->encoding;
2576 c.initiator = gsm->initiator;
2579 c.t3 = 0; /* Not supported */
2581 if (gsm->ftype == UIH)
2585 pr_debug("Ftype %d i %d\n", gsm->ftype, c.i);
2589 if (copy_to_user((void *)arg, &c, sizeof(c)))
2592 case GSMIOC_SETCONF:
2593 if (copy_from_user(&c, (void *)arg, sizeof(c)))
2595 return gsmld_config(tty, gsm, &c);
2597 return n_tty_ioctl_helper(tty, file, cmd, arg);
2606 static int gsm_mux_net_open(struct net_device *net)
2608 pr_debug("%s called\n", __func__);
2609 netif_start_queue(net);
2613 static int gsm_mux_net_close(struct net_device *net)
2615 netif_stop_queue(net);
2619 static struct net_device_stats *gsm_mux_net_get_stats(struct net_device *net)
2621 return &((struct gsm_mux_net *)netdev_priv(net))->stats;
2623 static void dlci_net_free(struct gsm_dlci *dlci)
2629 dlci->adaption = dlci->prev_adaption;
2630 dlci->data = dlci->prev_data;
2631 free_netdev(dlci->net);
2634 static void net_free(struct kref *ref)
2636 struct gsm_mux_net *mux_net;
2637 struct gsm_dlci *dlci;
2639 mux_net = container_of(ref, struct gsm_mux_net, ref);
2640 dlci = mux_net->dlci;
2643 unregister_netdev(dlci->net);
2644 dlci_net_free(dlci);
2648 static inline void muxnet_get(struct gsm_mux_net *mux_net)
2650 kref_get(&mux_net->ref);
2653 static inline void muxnet_put(struct gsm_mux_net *mux_net)
2655 kref_put(&mux_net->ref, net_free);
2658 static int gsm_mux_net_start_xmit(struct sk_buff *skb,
2659 struct net_device *net)
2661 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
2662 struct gsm_dlci *dlci = mux_net->dlci;
2663 muxnet_get(mux_net);
2665 skb_queue_head(&dlci->skb_list, skb);
2666 STATS(net).tx_packets++;
2667 STATS(net).tx_bytes += skb->len;
2668 gsm_dlci_data_kick(dlci);
2669 /* And tell the kernel when the last transmit started. */
2670 net->trans_start = jiffies;
2671 muxnet_put(mux_net);
2672 return NETDEV_TX_OK;
2675 /* called when a packet did not ack after watchdogtimeout */
2676 static void gsm_mux_net_tx_timeout(struct net_device *net)
2678 /* Tell syslog we are hosed. */
2679 dev_dbg(&net->dev, "Tx timed out.\n");
2681 /* Update statistics */
2682 STATS(net).tx_errors++;
2685 static void gsm_mux_rx_netchar(struct gsm_dlci *dlci,
2686 unsigned char *in_buf, int size)
2688 struct net_device *net = dlci->net;
2689 struct sk_buff *skb;
2690 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
2691 muxnet_get(mux_net);
2693 /* Allocate an sk_buff */
2694 skb = dev_alloc_skb(size + NET_IP_ALIGN);
2696 /* We got no receive buffer. */
2697 STATS(net).rx_dropped++;
2698 muxnet_put(mux_net);
2701 skb_reserve(skb, NET_IP_ALIGN);
2702 memcpy(skb_put(skb, size), in_buf, size);
2705 skb->protocol = __constant_htons(ETH_P_IP);
2707 /* Ship it off to the kernel */
2710 /* update out statistics */
2711 STATS(net).rx_packets++;
2712 STATS(net).rx_bytes += size;
2713 muxnet_put(mux_net);
2717 int gsm_change_mtu(struct net_device *net, int new_mtu)
2719 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
2720 if ((new_mtu < 8) || (new_mtu > mux_net->dlci->gsm->mtu))
2726 static void gsm_mux_net_init(struct net_device *net)
2728 static const struct net_device_ops gsm_netdev_ops = {
2729 .ndo_open = gsm_mux_net_open,
2730 .ndo_stop = gsm_mux_net_close,
2731 .ndo_start_xmit = gsm_mux_net_start_xmit,
2732 .ndo_tx_timeout = gsm_mux_net_tx_timeout,
2733 .ndo_get_stats = gsm_mux_net_get_stats,
2734 .ndo_change_mtu = gsm_change_mtu,
2737 net->netdev_ops = &gsm_netdev_ops;
2739 /* fill in the other fields */
2740 net->watchdog_timeo = GSM_NET_TX_TIMEOUT;
2741 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
2742 net->type = ARPHRD_NONE;
2743 net->tx_queue_len = 10;
2747 /* caller holds the dlci mutex */
2748 static void gsm_destroy_network(struct gsm_dlci *dlci)
2750 struct gsm_mux_net *mux_net;
2752 pr_debug("destroy network interface");
2755 mux_net = (struct gsm_mux_net *)netdev_priv(dlci->net);
2756 muxnet_put(mux_net);
2760 /* caller holds the dlci mutex */
2761 static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
2765 struct net_device *net;
2766 struct gsm_mux_net *mux_net;
2768 if (!capable(CAP_NET_ADMIN))
2771 /* Already in a non tty mode */
2772 if (dlci->adaption > 2)
2775 if (nc->protocol != htons(ETH_P_IP))
2776 return -EPROTONOSUPPORT;
2778 if (nc->adaption != 3 && nc->adaption != 4)
2779 return -EPROTONOSUPPORT;
2781 pr_debug("create network interface");
2784 if (nc->if_name[0] != '\0')
2785 netname = nc->if_name;
2786 net = alloc_netdev(sizeof(struct gsm_mux_net),
2790 pr_err("alloc_netdev failed");
2793 net->mtu = dlci->gsm->mtu;
2794 mux_net = (struct gsm_mux_net *)netdev_priv(net);
2795 mux_net->dlci = dlci;
2796 kref_init(&mux_net->ref);
2797 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */
2799 /* reconfigure dlci for network */
2800 dlci->prev_adaption = dlci->adaption;
2801 dlci->prev_data = dlci->data;
2802 dlci->adaption = nc->adaption;
2803 dlci->data = gsm_mux_rx_netchar;
2806 pr_debug("register netdev");
2807 retval = register_netdev(net);
2809 pr_err("network register fail %d\n", retval);
2810 dlci_net_free(dlci);
2813 return net->ifindex; /* return network index */
2816 /* Line discipline for real tty */
2817 struct tty_ldisc_ops tty_ldisc_packet = {
2818 .owner = THIS_MODULE,
2819 .magic = TTY_LDISC_MAGIC,
2822 .close = gsmld_close,
2823 .flush_buffer = gsmld_flush_buffer,
2824 .chars_in_buffer = gsmld_chars_in_buffer,
2826 .write = gsmld_write,
2827 .ioctl = gsmld_ioctl,
2829 .receive_buf = gsmld_receive_buf,
2830 .write_wakeup = gsmld_write_wakeup
2839 static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk)
2842 struct gsm_control *ctrl;
2848 modembits[0] = len << 1 | EA; /* Data bytes */
2849 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */
2850 modembits[2] = gsm_encode_modem(dlci) << 1 | EA;
2852 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */
2853 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1);
2856 return gsm_control_wait(dlci->gsm, ctrl);
2859 static int gsm_carrier_raised(struct tty_port *port)
2861 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2862 /* Not yet open so no carrier info */
2863 if (dlci->state != DLCI_OPEN)
2867 return dlci->modem_rx & TIOCM_CD;
2870 static void gsm_dtr_rts(struct tty_port *port, int onoff)
2872 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2873 unsigned int modem_tx = dlci->modem_tx;
2875 modem_tx |= TIOCM_DTR | TIOCM_RTS;
2877 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
2878 if (modem_tx != dlci->modem_tx) {
2879 dlci->modem_tx = modem_tx;
2880 gsmtty_modem_update(dlci, 0);
2884 static const struct tty_port_operations gsm_port_ops = {
2885 .carrier_raised = gsm_carrier_raised,
2886 .dtr_rts = gsm_dtr_rts,
2887 .destruct = gsm_dlci_free,
2890 static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty)
2892 struct gsm_mux *gsm;
2893 struct gsm_dlci *dlci;
2894 unsigned int line = tty->index;
2895 unsigned int mux = line >> 6;
2903 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
2904 if (gsm_mux[mux] == NULL)
2906 if (line == 0 || line > 61) /* 62/63 reserved */
2911 /* If DLCI 0 is not yet fully open return an error. This is ok from a locking
2912 perspective as we don't have to worry about this if DLCI0 is lost */
2913 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN)
2915 dlci = gsm->dlci[line];
2918 dlci = gsm_dlci_alloc(gsm, line);
2922 ret = tty_port_install(&dlci->port, driver, tty);
2929 tty->driver_data = dlci;
2934 static int gsmtty_open(struct tty_struct *tty, struct file *filp)
2936 struct gsm_dlci *dlci = tty->driver_data;
2937 struct tty_port *port = &dlci->port;
2941 dlci_get(dlci->gsm->dlci[0]);
2943 tty_port_tty_set(port, tty);
2946 /* We could in theory open and close before we wait - eg if we get
2947 a DM straight back. This is ok as that will have caused a hangup */
2948 set_bit(ASYNCB_INITIALIZED, &port->flags);
2949 /* Start sending off SABM messages */
2950 gsm_dlci_begin_open(dlci);
2951 /* And wait for virtual carrier */
2952 return tty_port_block_til_ready(port, tty, filp);
2955 static void gsmtty_close(struct tty_struct *tty, struct file *filp)
2957 struct gsm_dlci *dlci = tty->driver_data;
2958 struct gsm_mux *gsm;
2962 if (dlci->state == DLCI_CLOSED)
2964 mutex_lock(&dlci->mutex);
2965 gsm_destroy_network(dlci);
2966 mutex_unlock(&dlci->mutex);
2968 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
2970 gsm_dlci_begin_close(dlci);
2971 tty_port_close_end(&dlci->port, tty);
2972 tty_port_tty_set(&dlci->port, NULL);
2975 dlci_put(gsm->dlci[0]);
2979 static void gsmtty_hangup(struct tty_struct *tty)
2981 struct gsm_dlci *dlci = tty->driver_data;
2982 if (dlci->state == DLCI_CLOSED)
2984 tty_port_hangup(&dlci->port);
2985 gsm_dlci_begin_close(dlci);
2988 static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf,
2992 struct gsm_dlci *dlci = tty->driver_data;
2993 if (dlci->state == DLCI_CLOSED)
2995 /* Stuff the bytes into the fifo queue */
2996 sent = kfifo_in_locked(dlci->fifo, buf, len, &dlci->lock);
2997 /* Need to kick the channel */
2998 gsm_dlci_data_kick(dlci);
3002 static int gsmtty_write_room(struct tty_struct *tty)
3004 struct gsm_dlci *dlci = tty->driver_data;
3005 if (dlci->state == DLCI_CLOSED)
3007 return TX_SIZE - kfifo_len(dlci->fifo);
3010 static int gsmtty_chars_in_buffer(struct tty_struct *tty)
3012 struct gsm_dlci *dlci = tty->driver_data;
3013 if (dlci->state == DLCI_CLOSED)
3015 return kfifo_len(dlci->fifo);
3018 static void gsmtty_flush_buffer(struct tty_struct *tty)
3020 struct gsm_dlci *dlci = tty->driver_data;
3021 if (dlci->state == DLCI_CLOSED)
3023 /* Caution needed: If we implement reliable transport classes
3024 then the data being transmitted can't simply be junked once
3025 it has first hit the stack. Until then we can just blow it
3027 kfifo_reset(dlci->fifo);
3028 /* Need to unhook this DLCI from the transmit queue logic */
3031 static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
3033 /* The FIFO handles the queue so the kernel will do the right
3034 thing waiting on chars_in_buffer before calling us. No work
3038 static int gsmtty_tiocmget(struct tty_struct *tty)
3040 struct gsm_dlci *dlci = tty->driver_data;
3041 if (dlci->state == DLCI_CLOSED)
3043 return dlci->modem_rx;
3046 static int gsmtty_tiocmset(struct tty_struct *tty,
3047 unsigned int set, unsigned int clear)
3049 struct gsm_dlci *dlci = tty->driver_data;
3050 unsigned int modem_tx = dlci->modem_tx;
3052 if (dlci->state == DLCI_CLOSED)
3057 if (modem_tx != dlci->modem_tx) {
3058 dlci->modem_tx = modem_tx;
3059 return gsmtty_modem_update(dlci, 0);
3065 static int gsmtty_ioctl(struct tty_struct *tty,
3066 unsigned int cmd, unsigned long arg)
3068 struct gsm_dlci *dlci = tty->driver_data;
3069 struct gsm_netconfig nc;
3072 if (dlci->state == DLCI_CLOSED)
3075 case GSMIOC_ENABLE_NET:
3076 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc)))
3078 nc.if_name[IFNAMSIZ-1] = '\0';
3079 /* return net interface index or error code */
3080 mutex_lock(&dlci->mutex);
3081 index = gsm_create_network(dlci, &nc);
3082 mutex_unlock(&dlci->mutex);
3083 if (copy_to_user((void __user *)arg, &nc, sizeof(nc)))
3086 case GSMIOC_DISABLE_NET:
3087 if (!capable(CAP_NET_ADMIN))
3089 mutex_lock(&dlci->mutex);
3090 gsm_destroy_network(dlci);
3091 mutex_unlock(&dlci->mutex);
3094 return -ENOIOCTLCMD;
3098 static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old)
3100 struct gsm_dlci *dlci = tty->driver_data;
3101 if (dlci->state == DLCI_CLOSED)
3103 /* For the moment its fixed. In actual fact the speed information
3104 for the virtual channel can be propogated in both directions by
3105 the RPN control message. This however rapidly gets nasty as we
3106 then have to remap modem signals each way according to whether
3107 our virtual cable is null modem etc .. */
3108 tty_termios_copy_hw(&tty->termios, old);
3111 static void gsmtty_throttle(struct tty_struct *tty)
3113 struct gsm_dlci *dlci = tty->driver_data;
3114 if (dlci->state == DLCI_CLOSED)
3116 if (tty->termios.c_cflag & CRTSCTS)
3117 dlci->modem_tx &= ~TIOCM_DTR;
3118 dlci->throttled = 1;
3119 /* Send an MSC with DTR cleared */
3120 gsmtty_modem_update(dlci, 0);
3123 static void gsmtty_unthrottle(struct tty_struct *tty)
3125 struct gsm_dlci *dlci = tty->driver_data;
3126 if (dlci->state == DLCI_CLOSED)
3128 if (tty->termios.c_cflag & CRTSCTS)
3129 dlci->modem_tx |= TIOCM_DTR;
3130 dlci->throttled = 0;
3131 /* Send an MSC with DTR set */
3132 gsmtty_modem_update(dlci, 0);
3135 static int gsmtty_break_ctl(struct tty_struct *tty, int state)
3137 struct gsm_dlci *dlci = tty->driver_data;
3138 int encode = 0; /* Off */
3139 if (dlci->state == DLCI_CLOSED)
3142 if (state == -1) /* "On indefinitely" - we can't encode this
3145 else if (state > 0) {
3146 encode = state / 200; /* mS to encoding */
3148 encode = 0x0F; /* Best effort */
3150 return gsmtty_modem_update(dlci, encode);
3154 /* Virtual ttys for the demux */
3155 static const struct tty_operations gsmtty_ops = {
3156 .install = gsmtty_install,
3157 .open = gsmtty_open,
3158 .close = gsmtty_close,
3159 .write = gsmtty_write,
3160 .write_room = gsmtty_write_room,
3161 .chars_in_buffer = gsmtty_chars_in_buffer,
3162 .flush_buffer = gsmtty_flush_buffer,
3163 .ioctl = gsmtty_ioctl,
3164 .throttle = gsmtty_throttle,
3165 .unthrottle = gsmtty_unthrottle,
3166 .set_termios = gsmtty_set_termios,
3167 .hangup = gsmtty_hangup,
3168 .wait_until_sent = gsmtty_wait_until_sent,
3169 .tiocmget = gsmtty_tiocmget,
3170 .tiocmset = gsmtty_tiocmset,
3171 .break_ctl = gsmtty_break_ctl,
3176 static int __init gsm_init(void)
3178 /* Fill in our line protocol discipline, and register it */
3179 int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet);
3181 pr_err("n_gsm: can't register line discipline (err = %d)\n",
3186 gsm_tty_driver = alloc_tty_driver(256);
3187 if (!gsm_tty_driver) {
3188 tty_unregister_ldisc(N_GSM0710);
3189 pr_err("gsm_init: tty allocation failed.\n");
3192 gsm_tty_driver->driver_name = "gsmtty";
3193 gsm_tty_driver->name = "gsmtty";
3194 gsm_tty_driver->major = 0; /* Dynamic */
3195 gsm_tty_driver->minor_start = 0;
3196 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
3197 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
3198 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV
3199 | TTY_DRIVER_HARDWARE_BREAK;
3200 gsm_tty_driver->init_termios = tty_std_termios;
3202 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
3203 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
3205 spin_lock_init(&gsm_mux_lock);
3207 if (tty_register_driver(gsm_tty_driver)) {
3208 put_tty_driver(gsm_tty_driver);
3209 tty_unregister_ldisc(N_GSM0710);
3210 pr_err("gsm_init: tty registration failed.\n");
3213 pr_debug("gsm_init: loaded as %d,%d.\n",
3214 gsm_tty_driver->major, gsm_tty_driver->minor_start);
3218 static void __exit gsm_exit(void)
3220 int status = tty_unregister_ldisc(N_GSM0710);
3222 pr_err("n_gsm: can't unregister line discipline (err = %d)\n",
3224 tty_unregister_driver(gsm_tty_driver);
3225 put_tty_driver(gsm_tty_driver);
3228 module_init(gsm_init);
3229 module_exit(gsm_exit);
3232 MODULE_LICENSE("GPL");
3233 MODULE_ALIAS_LDISC(N_GSM0710);