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 unsigned int brk = 0;
1093 struct gsm_dlci *dlci;
1096 struct tty_struct *tty;
1098 while (gsm_read_ea(&addr, *dp++) == 0) {
1103 /* Must be at least one byte following the EA */
1109 /* Closed port, or invalid ? */
1110 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1112 dlci = gsm->dlci[addr];
1114 while (gsm_read_ea(&modem, *dp++) == 0) {
1121 while (gsm_read_ea(&brk, *dp++) == 0) {
1127 modem |= (brk & 0x7f);
1129 tty = tty_port_tty_get(&dlci->port);
1130 gsm_process_modem(tty, dlci, modem, clen);
1135 gsm_control_reply(gsm, CMD_MSC, data, clen);
1139 * gsm_control_rls - remote line status
1142 * @clen: data length
1144 * The modem sends us a two byte message on the control channel whenever
1145 * it wishes to send us an error state from the virtual link. Stuff
1146 * this into the uplink tty if present
1149 static void gsm_control_rls(struct gsm_mux *gsm, u8 *data, int clen)
1151 struct tty_port *port;
1152 unsigned int addr = 0 ;
1157 while (gsm_read_ea(&addr, *dp++) == 0) {
1162 /* Must be at least one byte following ea */
1167 /* Closed port, or invalid ? */
1168 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1172 if ((bits & 1) == 0)
1175 port = &gsm->dlci[addr]->port;
1178 tty_insert_flip_char(port, 0, TTY_OVERRUN);
1180 tty_insert_flip_char(port, 0, TTY_PARITY);
1182 tty_insert_flip_char(port, 0, TTY_FRAME);
1184 tty_flip_buffer_push(port);
1186 gsm_control_reply(gsm, CMD_RLS, data, clen);
1189 static void gsm_dlci_begin_close(struct gsm_dlci *dlci);
1192 * gsm_control_message - DLCI 0 control processing
1194 * @command: the command EA
1195 * @data: data beyond the command/length EAs
1198 * Input processor for control messages from the other end of the link.
1199 * Processes the incoming request and queues a response frame or an
1200 * NSC response if not supported
1203 static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
1207 unsigned long flags;
1211 struct gsm_dlci *dlci = gsm->dlci[0];
1212 /* Modem wishes to close down */
1216 gsm_dlci_begin_close(dlci);
1221 /* Modem wishes to test, reply with the data */
1222 gsm_control_reply(gsm, CMD_TEST, data, clen);
1225 /* Modem can accept data again */
1226 gsm->constipated = 0;
1227 gsm_control_reply(gsm, CMD_FCON, NULL, 0);
1228 /* Kick the link in case it is idling */
1229 spin_lock_irqsave(&gsm->tx_lock, flags);
1231 spin_unlock_irqrestore(&gsm->tx_lock, flags);
1234 /* Modem wants us to STFU */
1235 gsm->constipated = 1;
1236 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0);
1239 /* Out of band modem line change indicator for a DLCI */
1240 gsm_control_modem(gsm, data, clen);
1243 /* Out of band error reception for a DLCI */
1244 gsm_control_rls(gsm, data, clen);
1247 /* Modem wishes to enter power saving state */
1248 gsm_control_reply(gsm, CMD_PSC, NULL, 0);
1250 /* Optional unsupported commands */
1251 case CMD_PN: /* Parameter negotiation */
1252 case CMD_RPN: /* Remote port negotiation */
1253 case CMD_SNC: /* Service negotiation command */
1255 /* Reply to bad commands with an NSC */
1257 gsm_control_reply(gsm, CMD_NSC, buf, 1);
1263 * gsm_control_response - process a response to our control
1265 * @command: the command (response) EA
1266 * @data: data beyond the command/length EA
1269 * Process a response to an outstanding command. We only allow a single
1270 * control message in flight so this is fairly easy. All the clean up
1271 * is done by the caller, we just update the fields, flag it as done
1275 static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
1278 struct gsm_control *ctrl;
1279 unsigned long flags;
1281 spin_lock_irqsave(&gsm->control_lock, flags);
1283 ctrl = gsm->pending_cmd;
1284 /* Does the reply match our command */
1286 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) {
1287 /* Our command was replied to, kill the retry timer */
1288 del_timer(&gsm->t2_timer);
1289 gsm->pending_cmd = NULL;
1290 /* Rejected by the other end */
1291 if (command == CMD_NSC)
1292 ctrl->error = -EOPNOTSUPP;
1294 wake_up(&gsm->event);
1296 spin_unlock_irqrestore(&gsm->control_lock, flags);
1300 * gsm_control_transmit - send control packet
1302 * @ctrl: frame to send
1304 * Send out a pending control command (called under control lock)
1307 static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl)
1309 struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, gsm->ftype);
1312 msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */
1313 memcpy(msg->data + 1, ctrl->data, ctrl->len);
1314 gsm_data_queue(gsm->dlci[0], msg);
1318 * gsm_control_retransmit - retransmit a control frame
1319 * @data: pointer to our gsm object
1321 * Called off the T2 timer expiry in order to retransmit control frames
1322 * that have been lost in the system somewhere. The control_lock protects
1323 * us from colliding with another sender or a receive completion event.
1324 * In that situation the timer may still occur in a small window but
1325 * gsm->pending_cmd will be NULL and we just let the timer expire.
1328 static void gsm_control_retransmit(unsigned long data)
1330 struct gsm_mux *gsm = (struct gsm_mux *)data;
1331 struct gsm_control *ctrl;
1332 unsigned long flags;
1333 spin_lock_irqsave(&gsm->control_lock, flags);
1334 ctrl = gsm->pending_cmd;
1337 if (gsm->cretries == 0) {
1338 gsm->pending_cmd = NULL;
1339 ctrl->error = -ETIMEDOUT;
1341 spin_unlock_irqrestore(&gsm->control_lock, flags);
1342 wake_up(&gsm->event);
1345 gsm_control_transmit(gsm, ctrl);
1346 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1348 spin_unlock_irqrestore(&gsm->control_lock, flags);
1352 * gsm_control_send - send a control frame on DLCI 0
1353 * @gsm: the GSM channel
1354 * @command: command to send including CR bit
1355 * @data: bytes of data (must be kmalloced)
1356 * @len: length of the block to send
1358 * Queue and dispatch a control command. Only one command can be
1359 * active at a time. In theory more can be outstanding but the matching
1360 * gets really complicated so for now stick to one outstanding.
1363 static struct gsm_control *gsm_control_send(struct gsm_mux *gsm,
1364 unsigned int command, u8 *data, int clen)
1366 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control),
1368 unsigned long flags;
1372 wait_event(gsm->event, gsm->pending_cmd == NULL);
1373 spin_lock_irqsave(&gsm->control_lock, flags);
1374 if (gsm->pending_cmd != NULL) {
1375 spin_unlock_irqrestore(&gsm->control_lock, flags);
1378 ctrl->cmd = command;
1381 gsm->pending_cmd = ctrl;
1382 gsm->cretries = gsm->n2;
1383 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1384 gsm_control_transmit(gsm, ctrl);
1385 spin_unlock_irqrestore(&gsm->control_lock, flags);
1390 * gsm_control_wait - wait for a control to finish
1392 * @control: control we are waiting on
1394 * Waits for the control to complete or time out. Frees any used
1395 * resources and returns 0 for success, or an error if the remote
1396 * rejected or ignored the request.
1399 static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
1402 wait_event(gsm->event, control->done == 1);
1403 err = control->error;
1410 * DLCI level handling: Needs krefs
1414 * State transitions and timers
1418 * gsm_dlci_close - a DLCI has closed
1419 * @dlci: DLCI that closed
1421 * Perform processing when moving a DLCI into closed state. If there
1422 * is an attached tty this is hung up
1425 static void gsm_dlci_close(struct gsm_dlci *dlci)
1427 del_timer(&dlci->t1);
1429 pr_debug("DLCI %d goes closed.\n", dlci->addr);
1430 dlci->state = DLCI_CLOSED;
1431 if (dlci->addr != 0) {
1432 tty_port_tty_hangup(&dlci->port, false);
1433 kfifo_reset(dlci->fifo);
1435 dlci->gsm->dead = 1;
1436 wake_up(&dlci->gsm->event);
1437 /* A DLCI 0 close is a MUX termination so we need to kick that
1438 back to userspace somehow */
1442 * gsm_dlci_open - a DLCI has opened
1443 * @dlci: DLCI that opened
1445 * Perform processing when moving a DLCI into open state.
1448 static void gsm_dlci_open(struct gsm_dlci *dlci)
1450 /* Note that SABM UA .. SABM UA first UA lost can mean that we go
1452 del_timer(&dlci->t1);
1453 /* This will let a tty open continue */
1454 dlci->state = DLCI_OPEN;
1456 pr_debug("DLCI %d goes open.\n", dlci->addr);
1457 wake_up(&dlci->gsm->event);
1461 * gsm_dlci_t1 - T1 timer expiry
1462 * @dlci: DLCI that opened
1464 * The T1 timer handles retransmits of control frames (essentially of
1465 * SABM and DISC). We resend the command until the retry count runs out
1466 * in which case an opening port goes back to closed and a closing port
1467 * is simply put into closed state (any further frames from the other
1468 * end will get a DM response)
1471 static void gsm_dlci_t1(unsigned long data)
1473 struct gsm_dlci *dlci = (struct gsm_dlci *)data;
1474 struct gsm_mux *gsm = dlci->gsm;
1476 switch (dlci->state) {
1479 if (dlci->retries) {
1480 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1481 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1483 gsm_dlci_close(dlci);
1487 if (dlci->retries) {
1488 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1489 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1491 gsm_dlci_close(dlci);
1497 * gsm_dlci_begin_open - start channel open procedure
1498 * @dlci: DLCI to open
1500 * Commence opening a DLCI from the Linux side. We issue SABM messages
1501 * to the modem which should then reply with a UA, at which point we
1502 * will move into open state. Opening is done asynchronously with retry
1503 * running off timers and the responses.
1506 static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
1508 struct gsm_mux *gsm = dlci->gsm;
1509 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING)
1511 dlci->retries = gsm->n2;
1512 dlci->state = DLCI_OPENING;
1513 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1514 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1518 * gsm_dlci_begin_close - start channel open procedure
1519 * @dlci: DLCI to open
1521 * Commence closing a DLCI from the Linux side. We issue DISC messages
1522 * to the modem which should then reply with a UA, at which point we
1523 * will move into closed state. Closing is done asynchronously with retry
1524 * off timers. We may also receive a DM reply from the other end which
1525 * indicates the channel was already closed.
1528 static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
1530 struct gsm_mux *gsm = dlci->gsm;
1531 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
1533 dlci->retries = gsm->n2;
1534 dlci->state = DLCI_CLOSING;
1535 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1536 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1540 * gsm_dlci_data - data arrived
1542 * @data: block of bytes received
1543 * @len: length of received block
1545 * A UI or UIH frame has arrived which contains data for a channel
1546 * other than the control channel. If the relevant virtual tty is
1547 * open we shovel the bits down it, if not we drop them.
1550 static void gsm_dlci_data(struct gsm_dlci *dlci, u8 *data, int clen)
1553 struct tty_port *port = &dlci->port;
1554 struct tty_struct *tty;
1555 unsigned int modem = 0;
1559 pr_debug("%d bytes for tty\n", len);
1560 switch (dlci->adaption) {
1561 /* Unsupported types */
1562 /* Packetised interruptible data */
1565 /* Packetised uininterruptible voice/data */
1568 /* Asynchronous serial with line state in each frame */
1570 while (gsm_read_ea(&modem, *data++) == 0) {
1575 tty = tty_port_tty_get(port);
1577 gsm_process_modem(tty, dlci, modem, clen);
1580 /* Line state will go via DLCI 0 controls only */
1583 tty_insert_flip_string(port, data, len);
1584 tty_flip_buffer_push(port);
1589 * gsm_dlci_control - data arrived on control channel
1591 * @data: block of bytes received
1592 * @len: length of received block
1594 * A UI or UIH frame has arrived which contains data for DLCI 0 the
1595 * control channel. This should contain a command EA followed by
1596 * control data bytes. The command EA contains a command/response bit
1597 * and we divide up the work accordingly.
1600 static void gsm_dlci_command(struct gsm_dlci *dlci, u8 *data, int len)
1602 /* See what command is involved */
1603 unsigned int command = 0;
1605 if (gsm_read_ea(&command, *data++) == 1) {
1608 /* FIXME: this is properly an EA */
1610 /* Malformed command ? */
1614 gsm_control_message(dlci->gsm, command,
1617 gsm_control_response(dlci->gsm, command,
1625 * Allocate/Free DLCI channels
1629 * gsm_dlci_alloc - allocate a DLCI
1631 * @addr: address of the DLCI
1633 * Allocate and install a new DLCI object into the GSM mux.
1635 * FIXME: review locking races
1638 static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
1640 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC);
1643 spin_lock_init(&dlci->lock);
1644 mutex_init(&dlci->mutex);
1645 dlci->fifo = &dlci->_fifo;
1646 if (kfifo_alloc(&dlci->_fifo, 4096, GFP_KERNEL) < 0) {
1651 skb_queue_head_init(&dlci->skb_list);
1652 init_timer(&dlci->t1);
1653 dlci->t1.function = gsm_dlci_t1;
1654 dlci->t1.data = (unsigned long)dlci;
1655 tty_port_init(&dlci->port);
1656 dlci->port.ops = &gsm_port_ops;
1659 dlci->adaption = gsm->adaption;
1660 dlci->state = DLCI_CLOSED;
1662 dlci->data = gsm_dlci_data;
1664 dlci->data = gsm_dlci_command;
1665 gsm->dlci[addr] = dlci;
1670 * gsm_dlci_free - free DLCI
1671 * @dlci: DLCI to free
1677 static void gsm_dlci_free(struct tty_port *port)
1679 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
1681 del_timer_sync(&dlci->t1);
1682 dlci->gsm->dlci[dlci->addr] = NULL;
1683 kfifo_free(dlci->fifo);
1684 while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
1685 dev_kfree_skb(dlci->skb);
1689 static inline void dlci_get(struct gsm_dlci *dlci)
1691 tty_port_get(&dlci->port);
1694 static inline void dlci_put(struct gsm_dlci *dlci)
1696 tty_port_put(&dlci->port);
1699 static void gsm_destroy_network(struct gsm_dlci *dlci);
1702 * gsm_dlci_release - release DLCI
1703 * @dlci: DLCI to destroy
1705 * Release a DLCI. Actual free is deferred until either
1706 * mux is closed or tty is closed - whichever is last.
1710 static void gsm_dlci_release(struct gsm_dlci *dlci)
1712 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1714 mutex_lock(&dlci->mutex);
1715 gsm_destroy_network(dlci);
1716 mutex_unlock(&dlci->mutex);
1718 /* tty_vhangup needs the tty_lock, so unlock and
1719 relock after doing the hangup. */
1723 tty_port_tty_set(&dlci->port, NULL);
1726 dlci->state = DLCI_CLOSED;
1731 * LAPBish link layer logic
1735 * gsm_queue - a GSM frame is ready to process
1736 * @gsm: pointer to our gsm mux
1738 * At this point in time a frame has arrived and been demangled from
1739 * the line encoding. All the differences between the encodings have
1740 * been handled below us and the frame is unpacked into the structures.
1741 * The fcs holds the header FCS but any data FCS must be added here.
1744 static void gsm_queue(struct gsm_mux *gsm)
1746 struct gsm_dlci *dlci;
1749 /* We have to sneak a look at the packet body to do the FCS.
1750 A somewhat layering violation in the spec */
1752 if ((gsm->control & ~PF) == UI)
1753 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len);
1754 if (gsm->encoding == 0){
1755 /* WARNING: gsm->received_fcs is used for gsm->encoding = 0 only.
1756 In this case it contain the last piece of data
1757 required to generate final CRC */
1758 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs);
1760 if (gsm->fcs != GOOD_FCS) {
1763 pr_debug("BAD FCS %02x\n", gsm->fcs);
1766 address = gsm->address >> 1;
1767 if (address >= NUM_DLCI)
1770 cr = gsm->address & 1; /* C/R bit */
1772 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
1774 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */
1775 dlci = gsm->dlci[address];
1777 switch (gsm->control) {
1782 dlci = gsm_dlci_alloc(gsm, address);
1786 gsm_response(gsm, address, DM);
1788 gsm_response(gsm, address, UA);
1789 gsm_dlci_open(dlci);
1795 if (dlci == NULL || dlci->state == DLCI_CLOSED) {
1796 gsm_response(gsm, address, DM);
1799 /* Real close complete */
1800 gsm_response(gsm, address, UA);
1801 gsm_dlci_close(dlci);
1805 if (cr == 0 || dlci == NULL)
1807 switch (dlci->state) {
1809 gsm_dlci_close(dlci);
1812 gsm_dlci_open(dlci);
1816 case DM: /* DM can be valid unsolicited */
1822 gsm_dlci_close(dlci);
1832 if (dlci == NULL || dlci->state != DLCI_OPEN) {
1833 gsm_command(gsm, address, DM|PF);
1836 dlci->data(dlci, gsm->buf, gsm->len);
1849 * gsm0_receive - perform processing for non-transparency
1850 * @gsm: gsm data for this ldisc instance
1853 * Receive bytes in gsm mode 0
1856 static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
1860 switch (gsm->state) {
1861 case GSM_SEARCH: /* SOF marker */
1862 if (c == GSM0_SOF) {
1863 gsm->state = GSM_ADDRESS;
1866 gsm->fcs = INIT_FCS;
1869 case GSM_ADDRESS: /* Address EA */
1870 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1871 if (gsm_read_ea(&gsm->address, c))
1872 gsm->state = GSM_CONTROL;
1874 case GSM_CONTROL: /* Control Byte */
1875 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1877 gsm->state = GSM_LEN0;
1879 case GSM_LEN0: /* Length EA */
1880 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1881 if (gsm_read_ea(&gsm->len, c)) {
1882 if (gsm->len > gsm->mru) {
1884 gsm->state = GSM_SEARCH;
1889 gsm->state = GSM_FCS;
1891 gsm->state = GSM_DATA;
1894 gsm->state = GSM_LEN1;
1897 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1899 gsm->len |= len << 7;
1900 if (gsm->len > gsm->mru) {
1902 gsm->state = GSM_SEARCH;
1907 gsm->state = GSM_FCS;
1909 gsm->state = GSM_DATA;
1911 case GSM_DATA: /* Data */
1912 gsm->buf[gsm->count++] = c;
1913 if (gsm->count == gsm->len)
1914 gsm->state = GSM_FCS;
1916 case GSM_FCS: /* FCS follows the packet */
1917 gsm->received_fcs = c;
1919 gsm->state = GSM_SSOF;
1922 if (c == GSM0_SOF) {
1923 gsm->state = GSM_SEARCH;
1931 * gsm1_receive - perform processing for non-transparency
1932 * @gsm: gsm data for this ldisc instance
1935 * Receive bytes in mode 1 (Advanced option)
1938 static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
1940 if (c == GSM1_SOF) {
1941 /* EOF is only valid in frame if we have got to the data state
1942 and received at least one byte (the FCS) */
1943 if (gsm->state == GSM_DATA && gsm->count) {
1944 /* Extract the FCS */
1946 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
1947 gsm->len = gsm->count;
1949 gsm->state = GSM_START;
1952 /* Any partial frame was a runt so go back to start */
1953 if (gsm->state != GSM_START) {
1955 gsm->state = GSM_START;
1957 /* A SOF in GSM_START means we are still reading idling or
1962 if (c == GSM1_ESCAPE) {
1967 /* Only an unescaped SOF gets us out of GSM search */
1968 if (gsm->state == GSM_SEARCH)
1972 c ^= GSM1_ESCAPE_BITS;
1975 switch (gsm->state) {
1976 case GSM_START: /* First byte after SOF */
1978 gsm->state = GSM_ADDRESS;
1979 gsm->fcs = INIT_FCS;
1981 case GSM_ADDRESS: /* Address continuation */
1982 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1983 if (gsm_read_ea(&gsm->address, c))
1984 gsm->state = GSM_CONTROL;
1986 case GSM_CONTROL: /* Control Byte */
1987 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1990 gsm->state = GSM_DATA;
1992 case GSM_DATA: /* Data */
1993 if (gsm->count > gsm->mru) { /* Allow one for the FCS */
1994 gsm->state = GSM_OVERRUN;
1997 gsm->buf[gsm->count++] = c;
1999 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */
2005 * gsm_error - handle tty error
2007 * @data: byte received (may be invalid)
2008 * @flag: error received
2010 * Handle an error in the receipt of data for a frame. Currently we just
2011 * go back to hunting for a SOF.
2013 * FIXME: better diagnostics ?
2016 static void gsm_error(struct gsm_mux *gsm,
2017 unsigned char data, unsigned char flag)
2019 gsm->state = GSM_SEARCH;
2024 * gsm_cleanup_mux - generic GSM protocol cleanup
2027 * Clean up the bits of the mux which are the same for all framing
2028 * protocols. Remove the mux from the mux table, stop all the timers
2029 * and then shut down each device hanging up the channels as we go.
2032 void gsm_cleanup_mux(struct gsm_mux *gsm)
2035 struct gsm_dlci *dlci = gsm->dlci[0];
2036 struct gsm_msg *txq, *ntxq;
2037 struct gsm_control *gc;
2041 spin_lock(&gsm_mux_lock);
2042 for (i = 0; i < MAX_MUX; i++) {
2043 if (gsm_mux[i] == gsm) {
2048 spin_unlock(&gsm_mux_lock);
2049 WARN_ON(i == MAX_MUX);
2051 /* In theory disconnecting DLCI 0 is sufficient but for some
2052 modems this is apparently not the case. */
2054 gc = gsm_control_send(gsm, CMD_CLD, NULL, 0);
2056 gsm_control_wait(gsm, gc);
2058 del_timer_sync(&gsm->t2_timer);
2059 /* Now we are sure T2 has stopped */
2062 gsm_dlci_begin_close(dlci);
2063 wait_event_interruptible(gsm->event,
2064 dlci->state == DLCI_CLOSED);
2066 /* Free up any link layer users */
2067 for (i = 0; i < NUM_DLCI; i++)
2069 gsm_dlci_release(gsm->dlci[i]);
2070 /* Now wipe the queues */
2071 list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list)
2073 INIT_LIST_HEAD(&gsm->tx_list);
2075 EXPORT_SYMBOL_GPL(gsm_cleanup_mux);
2078 * gsm_activate_mux - generic GSM setup
2081 * Set up the bits of the mux which are the same for all framing
2082 * protocols. Add the mux to the mux table so it can be opened and
2083 * finally kick off connecting to DLCI 0 on the modem.
2086 int gsm_activate_mux(struct gsm_mux *gsm)
2088 struct gsm_dlci *dlci;
2091 init_timer(&gsm->t2_timer);
2092 gsm->t2_timer.function = gsm_control_retransmit;
2093 gsm->t2_timer.data = (unsigned long)gsm;
2094 init_waitqueue_head(&gsm->event);
2095 spin_lock_init(&gsm->control_lock);
2096 spin_lock_init(&gsm->tx_lock);
2098 if (gsm->encoding == 0)
2099 gsm->receive = gsm0_receive;
2101 gsm->receive = gsm1_receive;
2102 gsm->error = gsm_error;
2104 spin_lock(&gsm_mux_lock);
2105 for (i = 0; i < MAX_MUX; i++) {
2106 if (gsm_mux[i] == NULL) {
2112 spin_unlock(&gsm_mux_lock);
2116 dlci = gsm_dlci_alloc(gsm, 0);
2119 gsm->dead = 0; /* Tty opens are now permissible */
2122 EXPORT_SYMBOL_GPL(gsm_activate_mux);
2125 * gsm_free_mux - free up a mux
2128 * Dispose of allocated resources for a dead mux
2130 void gsm_free_mux(struct gsm_mux *gsm)
2132 kfree(gsm->txframe);
2136 EXPORT_SYMBOL_GPL(gsm_free_mux);
2139 * gsm_free_muxr - free up a mux
2142 * Dispose of allocated resources for a dead mux
2144 static void gsm_free_muxr(struct kref *ref)
2146 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref);
2150 static inline void mux_get(struct gsm_mux *gsm)
2152 kref_get(&gsm->ref);
2155 static inline void mux_put(struct gsm_mux *gsm)
2157 kref_put(&gsm->ref, gsm_free_muxr);
2161 * gsm_alloc_mux - allocate a mux
2163 * Creates a new mux ready for activation.
2166 struct gsm_mux *gsm_alloc_mux(void)
2168 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
2171 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL);
2172 if (gsm->buf == NULL) {
2176 gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL);
2177 if (gsm->txframe == NULL) {
2182 spin_lock_init(&gsm->lock);
2183 kref_init(&gsm->ref);
2184 INIT_LIST_HEAD(&gsm->tx_list);
2192 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
2194 gsm->dead = 1; /* Avoid early tty opens */
2198 EXPORT_SYMBOL_GPL(gsm_alloc_mux);
2201 * gsmld_output - write to link
2203 * @data: bytes to output
2206 * Write a block of data from the GSM mux to the data channel. This
2207 * will eventually be serialized from above but at the moment isn't.
2210 static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
2212 if (tty_write_room(gsm->tty) < len) {
2213 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
2217 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET,
2219 gsm->tty->ops->write(gsm->tty, data, len);
2224 * gsmld_attach_gsm - mode set up
2225 * @tty: our tty structure
2228 * Set up the MUX for basic mode and commence connecting to the
2229 * modem. Currently called from the line discipline set up but
2230 * will need moving to an ioctl path.
2233 static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2236 int base = gsm->num << 6; /* Base for this MUX */
2238 gsm->tty = tty_kref_get(tty);
2239 gsm->output = gsmld_output;
2240 ret = gsm_activate_mux(gsm);
2242 tty_kref_put(gsm->tty);
2244 /* Don't register device 0 - this is the control channel and not
2245 a usable tty interface */
2246 for (i = 1; i < NUM_DLCI; i++)
2247 tty_register_device(gsm_tty_driver, base + i, NULL);
2254 * gsmld_detach_gsm - stop doing 0710 mux
2255 * @tty: tty attached to the mux
2258 * Shutdown and then clean up the resources used by the line discipline
2261 static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2264 int base = gsm->num << 6; /* Base for this MUX */
2266 WARN_ON(tty != gsm->tty);
2267 for (i = 1; i < NUM_DLCI; i++)
2268 tty_unregister_device(gsm_tty_driver, base + i);
2269 gsm_cleanup_mux(gsm);
2270 tty_kref_put(gsm->tty);
2274 static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
2275 char *fp, int count)
2277 struct gsm_mux *gsm = tty->disc_data;
2278 const unsigned char *dp;
2285 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET,
2288 for (i = count, dp = cp, f = fp; i; i--, dp++) {
2292 gsm->receive(gsm, *dp);
2298 gsm->error(gsm, *dp, flags);
2301 WARN_ONCE(1, "%s: unknown flag %d\n",
2302 tty_name(tty, buf), flags);
2306 /* FASYNC if needed ? */
2307 /* If clogged call tty_throttle(tty); */
2311 * gsmld_chars_in_buffer - report available bytes
2314 * Report the number of characters buffered to be delivered to user
2315 * at this instant in time.
2320 static ssize_t gsmld_chars_in_buffer(struct tty_struct *tty)
2326 * gsmld_flush_buffer - clean input queue
2327 * @tty: terminal device
2329 * Flush the input buffer. Called when the line discipline is
2330 * being closed, when the tty layer wants the buffer flushed (eg
2334 static void gsmld_flush_buffer(struct tty_struct *tty)
2339 * gsmld_close - close the ldisc for this tty
2342 * Called from the terminal layer when this line discipline is
2343 * being shut down, either because of a close or becsuse of a
2344 * discipline change. The function will not be called while other
2345 * ldisc methods are in progress.
2348 static void gsmld_close(struct tty_struct *tty)
2350 struct gsm_mux *gsm = tty->disc_data;
2352 gsmld_detach_gsm(tty, gsm);
2354 gsmld_flush_buffer(tty);
2355 /* Do other clean up here */
2360 * gsmld_open - open an ldisc
2361 * @tty: terminal to open
2363 * Called when this line discipline is being attached to the
2364 * terminal device. Can sleep. Called serialized so that no
2365 * other events will occur in parallel. No further open will occur
2369 static int gsmld_open(struct tty_struct *tty)
2371 struct gsm_mux *gsm;
2373 if (tty->ops->write == NULL)
2376 /* Attach our ldisc data */
2377 gsm = gsm_alloc_mux();
2381 tty->disc_data = gsm;
2382 tty->receive_room = 65536;
2384 /* Attach the initial passive connection */
2386 return gsmld_attach_gsm(tty, gsm);
2390 * gsmld_write_wakeup - asynchronous I/O notifier
2393 * Required for the ptys, serial driver etc. since processes
2394 * that attach themselves to the master and rely on ASYNC
2395 * IO must be woken up
2398 static void gsmld_write_wakeup(struct tty_struct *tty)
2400 struct gsm_mux *gsm = tty->disc_data;
2401 unsigned long flags;
2404 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2405 spin_lock_irqsave(&gsm->tx_lock, flags);
2407 if (gsm->tx_bytes < TX_THRESH_LO) {
2408 gsm_dlci_data_sweep(gsm);
2410 spin_unlock_irqrestore(&gsm->tx_lock, flags);
2414 * gsmld_read - read function for tty
2416 * @file: file object
2417 * @buf: userspace buffer pointer
2420 * Perform reads for the line discipline. We are guaranteed that the
2421 * line discipline will not be closed under us but we may get multiple
2422 * parallel readers and must handle this ourselves. We may also get
2423 * a hangup. Always called in user context, may sleep.
2425 * This code must be sure never to sleep through a hangup.
2428 static ssize_t gsmld_read(struct tty_struct *tty, struct file *file,
2429 unsigned char __user *buf, size_t nr)
2435 * gsmld_write - write function for tty
2437 * @file: file object
2438 * @buf: userspace buffer pointer
2441 * Called when the owner of the device wants to send a frame
2442 * itself (or some other control data). The data is transferred
2443 * as-is and must be properly framed and checksummed as appropriate
2444 * by userspace. Frames are either sent whole or not at all as this
2445 * avoids pain user side.
2448 static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
2449 const unsigned char *buf, size_t nr)
2451 int space = tty_write_room(tty);
2453 return tty->ops->write(tty, buf, nr);
2454 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2459 * gsmld_poll - poll method for N_GSM0710
2460 * @tty: terminal device
2461 * @file: file accessing it
2464 * Called when the line discipline is asked to poll() for data or
2465 * for special events. This code is not serialized with respect to
2466 * other events save open/close.
2468 * This code must be sure never to sleep through a hangup.
2469 * Called without the kernel lock held - fine
2472 static unsigned int gsmld_poll(struct tty_struct *tty, struct file *file,
2475 unsigned int mask = 0;
2476 struct gsm_mux *gsm = tty->disc_data;
2478 poll_wait(file, &tty->read_wait, wait);
2479 poll_wait(file, &tty->write_wait, wait);
2480 if (tty_hung_up_p(file))
2482 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
2483 mask |= POLLOUT | POLLWRNORM;
2489 static int gsmld_config(struct tty_struct *tty, struct gsm_mux *gsm,
2490 struct gsm_config *c)
2493 int need_restart = 0;
2495 /* Stuff we don't support yet - UI or I frame transport, windowing */
2496 if ((c->adaption != 1 && c->adaption != 2) || c->k)
2498 /* Check the MRU/MTU range looks sane */
2499 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8)
2503 if (c->encapsulation > 1) /* Basic, advanced, no I */
2505 if (c->initiator > 1)
2507 if (c->i == 0 || c->i > 2) /* UIH and UI only */
2510 * See what is needed for reconfiguration
2514 if (c->t1 != 0 && c->t1 != gsm->t1)
2516 if (c->t2 != 0 && c->t2 != gsm->t2)
2518 if (c->encapsulation != gsm->encoding)
2520 if (c->adaption != gsm->adaption)
2523 if (c->initiator != gsm->initiator)
2525 if (c->mru != gsm->mru)
2527 if (c->mtu != gsm->mtu)
2531 * Close down what is needed, restart and initiate the new
2535 if (need_close || need_restart) {
2536 gsm_dlci_begin_close(gsm->dlci[0]);
2537 /* This will timeout if the link is down due to N2 expiring */
2538 wait_event_interruptible(gsm->event,
2539 gsm->dlci[0]->state == DLCI_CLOSED);
2540 if (signal_pending(current))
2544 gsm_cleanup_mux(gsm);
2546 gsm->initiator = c->initiator;
2549 gsm->encoding = c->encapsulation;
2550 gsm->adaption = c->adaption;
2563 /* FIXME: We need to separate activation/deactivation from adding
2564 and removing from the mux array */
2566 gsm_activate_mux(gsm);
2567 if (gsm->initiator && need_close)
2568 gsm_dlci_begin_open(gsm->dlci[0]);
2572 static int gsmld_ioctl(struct tty_struct *tty, struct file *file,
2573 unsigned int cmd, unsigned long arg)
2575 struct gsm_config c;
2576 struct gsm_mux *gsm = tty->disc_data;
2579 case GSMIOC_GETCONF:
2580 memset(&c, 0, sizeof(c));
2581 c.adaption = gsm->adaption;
2582 c.encapsulation = gsm->encoding;
2583 c.initiator = gsm->initiator;
2586 c.t3 = 0; /* Not supported */
2588 if (gsm->ftype == UIH)
2592 pr_debug("Ftype %d i %d\n", gsm->ftype, c.i);
2596 if (copy_to_user((void *)arg, &c, sizeof(c)))
2599 case GSMIOC_SETCONF:
2600 if (copy_from_user(&c, (void *)arg, sizeof(c)))
2602 return gsmld_config(tty, gsm, &c);
2604 return n_tty_ioctl_helper(tty, file, cmd, arg);
2613 static int gsm_mux_net_open(struct net_device *net)
2615 pr_debug("%s called\n", __func__);
2616 netif_start_queue(net);
2620 static int gsm_mux_net_close(struct net_device *net)
2622 netif_stop_queue(net);
2626 static struct net_device_stats *gsm_mux_net_get_stats(struct net_device *net)
2628 return &((struct gsm_mux_net *)netdev_priv(net))->stats;
2630 static void dlci_net_free(struct gsm_dlci *dlci)
2636 dlci->adaption = dlci->prev_adaption;
2637 dlci->data = dlci->prev_data;
2638 free_netdev(dlci->net);
2641 static void net_free(struct kref *ref)
2643 struct gsm_mux_net *mux_net;
2644 struct gsm_dlci *dlci;
2646 mux_net = container_of(ref, struct gsm_mux_net, ref);
2647 dlci = mux_net->dlci;
2650 unregister_netdev(dlci->net);
2651 dlci_net_free(dlci);
2655 static inline void muxnet_get(struct gsm_mux_net *mux_net)
2657 kref_get(&mux_net->ref);
2660 static inline void muxnet_put(struct gsm_mux_net *mux_net)
2662 kref_put(&mux_net->ref, net_free);
2665 static int gsm_mux_net_start_xmit(struct sk_buff *skb,
2666 struct net_device *net)
2668 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
2669 struct gsm_dlci *dlci = mux_net->dlci;
2670 muxnet_get(mux_net);
2672 skb_queue_head(&dlci->skb_list, skb);
2673 STATS(net).tx_packets++;
2674 STATS(net).tx_bytes += skb->len;
2675 gsm_dlci_data_kick(dlci);
2676 /* And tell the kernel when the last transmit started. */
2677 net->trans_start = jiffies;
2678 muxnet_put(mux_net);
2679 return NETDEV_TX_OK;
2682 /* called when a packet did not ack after watchdogtimeout */
2683 static void gsm_mux_net_tx_timeout(struct net_device *net)
2685 /* Tell syslog we are hosed. */
2686 dev_dbg(&net->dev, "Tx timed out.\n");
2688 /* Update statistics */
2689 STATS(net).tx_errors++;
2692 static void gsm_mux_rx_netchar(struct gsm_dlci *dlci,
2693 unsigned char *in_buf, int size)
2695 struct net_device *net = dlci->net;
2696 struct sk_buff *skb;
2697 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
2698 muxnet_get(mux_net);
2700 /* Allocate an sk_buff */
2701 skb = dev_alloc_skb(size + NET_IP_ALIGN);
2703 /* We got no receive buffer. */
2704 STATS(net).rx_dropped++;
2705 muxnet_put(mux_net);
2708 skb_reserve(skb, NET_IP_ALIGN);
2709 memcpy(skb_put(skb, size), in_buf, size);
2712 skb->protocol = __constant_htons(ETH_P_IP);
2714 /* Ship it off to the kernel */
2717 /* update out statistics */
2718 STATS(net).rx_packets++;
2719 STATS(net).rx_bytes += size;
2720 muxnet_put(mux_net);
2724 int gsm_change_mtu(struct net_device *net, int new_mtu)
2726 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
2727 if ((new_mtu < 8) || (new_mtu > mux_net->dlci->gsm->mtu))
2733 static void gsm_mux_net_init(struct net_device *net)
2735 static const struct net_device_ops gsm_netdev_ops = {
2736 .ndo_open = gsm_mux_net_open,
2737 .ndo_stop = gsm_mux_net_close,
2738 .ndo_start_xmit = gsm_mux_net_start_xmit,
2739 .ndo_tx_timeout = gsm_mux_net_tx_timeout,
2740 .ndo_get_stats = gsm_mux_net_get_stats,
2741 .ndo_change_mtu = gsm_change_mtu,
2744 net->netdev_ops = &gsm_netdev_ops;
2746 /* fill in the other fields */
2747 net->watchdog_timeo = GSM_NET_TX_TIMEOUT;
2748 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
2749 net->type = ARPHRD_NONE;
2750 net->tx_queue_len = 10;
2754 /* caller holds the dlci mutex */
2755 static void gsm_destroy_network(struct gsm_dlci *dlci)
2757 struct gsm_mux_net *mux_net;
2759 pr_debug("destroy network interface");
2762 mux_net = (struct gsm_mux_net *)netdev_priv(dlci->net);
2763 muxnet_put(mux_net);
2767 /* caller holds the dlci mutex */
2768 static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
2772 struct net_device *net;
2773 struct gsm_mux_net *mux_net;
2775 if (!capable(CAP_NET_ADMIN))
2778 /* Already in a non tty mode */
2779 if (dlci->adaption > 2)
2782 if (nc->protocol != htons(ETH_P_IP))
2783 return -EPROTONOSUPPORT;
2785 if (nc->adaption != 3 && nc->adaption != 4)
2786 return -EPROTONOSUPPORT;
2788 pr_debug("create network interface");
2791 if (nc->if_name[0] != '\0')
2792 netname = nc->if_name;
2793 net = alloc_netdev(sizeof(struct gsm_mux_net),
2797 pr_err("alloc_netdev failed");
2800 net->mtu = dlci->gsm->mtu;
2801 mux_net = (struct gsm_mux_net *)netdev_priv(net);
2802 mux_net->dlci = dlci;
2803 kref_init(&mux_net->ref);
2804 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */
2806 /* reconfigure dlci for network */
2807 dlci->prev_adaption = dlci->adaption;
2808 dlci->prev_data = dlci->data;
2809 dlci->adaption = nc->adaption;
2810 dlci->data = gsm_mux_rx_netchar;
2813 pr_debug("register netdev");
2814 retval = register_netdev(net);
2816 pr_err("network register fail %d\n", retval);
2817 dlci_net_free(dlci);
2820 return net->ifindex; /* return network index */
2823 /* Line discipline for real tty */
2824 struct tty_ldisc_ops tty_ldisc_packet = {
2825 .owner = THIS_MODULE,
2826 .magic = TTY_LDISC_MAGIC,
2829 .close = gsmld_close,
2830 .flush_buffer = gsmld_flush_buffer,
2831 .chars_in_buffer = gsmld_chars_in_buffer,
2833 .write = gsmld_write,
2834 .ioctl = gsmld_ioctl,
2836 .receive_buf = gsmld_receive_buf,
2837 .write_wakeup = gsmld_write_wakeup
2846 static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk)
2849 struct gsm_control *ctrl;
2855 modembits[0] = len << 1 | EA; /* Data bytes */
2856 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */
2857 modembits[2] = gsm_encode_modem(dlci) << 1 | EA;
2859 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */
2860 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1);
2863 return gsm_control_wait(dlci->gsm, ctrl);
2866 static int gsm_carrier_raised(struct tty_port *port)
2868 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2869 /* Not yet open so no carrier info */
2870 if (dlci->state != DLCI_OPEN)
2874 return dlci->modem_rx & TIOCM_CD;
2877 static void gsm_dtr_rts(struct tty_port *port, int onoff)
2879 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2880 unsigned int modem_tx = dlci->modem_tx;
2882 modem_tx |= TIOCM_DTR | TIOCM_RTS;
2884 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
2885 if (modem_tx != dlci->modem_tx) {
2886 dlci->modem_tx = modem_tx;
2887 gsmtty_modem_update(dlci, 0);
2891 static const struct tty_port_operations gsm_port_ops = {
2892 .carrier_raised = gsm_carrier_raised,
2893 .dtr_rts = gsm_dtr_rts,
2894 .destruct = gsm_dlci_free,
2897 static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty)
2899 struct gsm_mux *gsm;
2900 struct gsm_dlci *dlci;
2901 unsigned int line = tty->index;
2902 unsigned int mux = line >> 6;
2910 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
2911 if (gsm_mux[mux] == NULL)
2913 if (line == 0 || line > 61) /* 62/63 reserved */
2918 /* If DLCI 0 is not yet fully open return an error. This is ok from a locking
2919 perspective as we don't have to worry about this if DLCI0 is lost */
2920 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN)
2922 dlci = gsm->dlci[line];
2925 dlci = gsm_dlci_alloc(gsm, line);
2929 ret = tty_port_install(&dlci->port, driver, tty);
2936 tty->driver_data = dlci;
2941 static int gsmtty_open(struct tty_struct *tty, struct file *filp)
2943 struct gsm_dlci *dlci = tty->driver_data;
2944 struct tty_port *port = &dlci->port;
2948 dlci_get(dlci->gsm->dlci[0]);
2950 tty_port_tty_set(port, tty);
2953 /* We could in theory open and close before we wait - eg if we get
2954 a DM straight back. This is ok as that will have caused a hangup */
2955 set_bit(ASYNCB_INITIALIZED, &port->flags);
2956 /* Start sending off SABM messages */
2957 gsm_dlci_begin_open(dlci);
2958 /* And wait for virtual carrier */
2959 return tty_port_block_til_ready(port, tty, filp);
2962 static void gsmtty_close(struct tty_struct *tty, struct file *filp)
2964 struct gsm_dlci *dlci = tty->driver_data;
2965 struct gsm_mux *gsm;
2969 if (dlci->state == DLCI_CLOSED)
2971 mutex_lock(&dlci->mutex);
2972 gsm_destroy_network(dlci);
2973 mutex_unlock(&dlci->mutex);
2975 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
2977 gsm_dlci_begin_close(dlci);
2978 if (test_bit(ASYNCB_INITIALIZED, &dlci->port.flags)) {
2980 tty_port_lower_dtr_rts(&dlci->port);
2982 tty_port_close_end(&dlci->port, tty);
2983 tty_port_tty_set(&dlci->port, NULL);
2986 dlci_put(gsm->dlci[0]);
2990 static void gsmtty_hangup(struct tty_struct *tty)
2992 struct gsm_dlci *dlci = tty->driver_data;
2993 if (dlci->state == DLCI_CLOSED)
2995 tty_port_hangup(&dlci->port);
2996 gsm_dlci_begin_close(dlci);
2999 static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf,
3003 struct gsm_dlci *dlci = tty->driver_data;
3004 if (dlci->state == DLCI_CLOSED)
3006 /* Stuff the bytes into the fifo queue */
3007 sent = kfifo_in_locked(dlci->fifo, buf, len, &dlci->lock);
3008 /* Need to kick the channel */
3009 gsm_dlci_data_kick(dlci);
3013 static int gsmtty_write_room(struct tty_struct *tty)
3015 struct gsm_dlci *dlci = tty->driver_data;
3016 if (dlci->state == DLCI_CLOSED)
3018 return TX_SIZE - kfifo_len(dlci->fifo);
3021 static int gsmtty_chars_in_buffer(struct tty_struct *tty)
3023 struct gsm_dlci *dlci = tty->driver_data;
3024 if (dlci->state == DLCI_CLOSED)
3026 return kfifo_len(dlci->fifo);
3029 static void gsmtty_flush_buffer(struct tty_struct *tty)
3031 struct gsm_dlci *dlci = tty->driver_data;
3032 if (dlci->state == DLCI_CLOSED)
3034 /* Caution needed: If we implement reliable transport classes
3035 then the data being transmitted can't simply be junked once
3036 it has first hit the stack. Until then we can just blow it
3038 kfifo_reset(dlci->fifo);
3039 /* Need to unhook this DLCI from the transmit queue logic */
3042 static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
3044 /* The FIFO handles the queue so the kernel will do the right
3045 thing waiting on chars_in_buffer before calling us. No work
3049 static int gsmtty_tiocmget(struct tty_struct *tty)
3051 struct gsm_dlci *dlci = tty->driver_data;
3052 if (dlci->state == DLCI_CLOSED)
3054 return dlci->modem_rx;
3057 static int gsmtty_tiocmset(struct tty_struct *tty,
3058 unsigned int set, unsigned int clear)
3060 struct gsm_dlci *dlci = tty->driver_data;
3061 unsigned int modem_tx = dlci->modem_tx;
3063 if (dlci->state == DLCI_CLOSED)
3068 if (modem_tx != dlci->modem_tx) {
3069 dlci->modem_tx = modem_tx;
3070 return gsmtty_modem_update(dlci, 0);
3076 static int gsmtty_ioctl(struct tty_struct *tty,
3077 unsigned int cmd, unsigned long arg)
3079 struct gsm_dlci *dlci = tty->driver_data;
3080 struct gsm_netconfig nc;
3083 if (dlci->state == DLCI_CLOSED)
3086 case GSMIOC_ENABLE_NET:
3087 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc)))
3089 nc.if_name[IFNAMSIZ-1] = '\0';
3090 /* return net interface index or error code */
3091 mutex_lock(&dlci->mutex);
3092 index = gsm_create_network(dlci, &nc);
3093 mutex_unlock(&dlci->mutex);
3094 if (copy_to_user((void __user *)arg, &nc, sizeof(nc)))
3097 case GSMIOC_DISABLE_NET:
3098 if (!capable(CAP_NET_ADMIN))
3100 mutex_lock(&dlci->mutex);
3101 gsm_destroy_network(dlci);
3102 mutex_unlock(&dlci->mutex);
3105 return -ENOIOCTLCMD;
3109 static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old)
3111 struct gsm_dlci *dlci = tty->driver_data;
3112 if (dlci->state == DLCI_CLOSED)
3114 /* For the moment its fixed. In actual fact the speed information
3115 for the virtual channel can be propogated in both directions by
3116 the RPN control message. This however rapidly gets nasty as we
3117 then have to remap modem signals each way according to whether
3118 our virtual cable is null modem etc .. */
3119 tty_termios_copy_hw(&tty->termios, old);
3122 static void gsmtty_throttle(struct tty_struct *tty)
3124 struct gsm_dlci *dlci = tty->driver_data;
3125 if (dlci->state == DLCI_CLOSED)
3127 if (tty->termios.c_cflag & CRTSCTS)
3128 dlci->modem_tx &= ~TIOCM_DTR;
3129 dlci->throttled = 1;
3130 /* Send an MSC with DTR cleared */
3131 gsmtty_modem_update(dlci, 0);
3134 static void gsmtty_unthrottle(struct tty_struct *tty)
3136 struct gsm_dlci *dlci = tty->driver_data;
3137 if (dlci->state == DLCI_CLOSED)
3139 if (tty->termios.c_cflag & CRTSCTS)
3140 dlci->modem_tx |= TIOCM_DTR;
3141 dlci->throttled = 0;
3142 /* Send an MSC with DTR set */
3143 gsmtty_modem_update(dlci, 0);
3146 static int gsmtty_break_ctl(struct tty_struct *tty, int state)
3148 struct gsm_dlci *dlci = tty->driver_data;
3149 int encode = 0; /* Off */
3150 if (dlci->state == DLCI_CLOSED)
3153 if (state == -1) /* "On indefinitely" - we can't encode this
3156 else if (state > 0) {
3157 encode = state / 200; /* mS to encoding */
3159 encode = 0x0F; /* Best effort */
3161 return gsmtty_modem_update(dlci, encode);
3165 /* Virtual ttys for the demux */
3166 static const struct tty_operations gsmtty_ops = {
3167 .install = gsmtty_install,
3168 .open = gsmtty_open,
3169 .close = gsmtty_close,
3170 .write = gsmtty_write,
3171 .write_room = gsmtty_write_room,
3172 .chars_in_buffer = gsmtty_chars_in_buffer,
3173 .flush_buffer = gsmtty_flush_buffer,
3174 .ioctl = gsmtty_ioctl,
3175 .throttle = gsmtty_throttle,
3176 .unthrottle = gsmtty_unthrottle,
3177 .set_termios = gsmtty_set_termios,
3178 .hangup = gsmtty_hangup,
3179 .wait_until_sent = gsmtty_wait_until_sent,
3180 .tiocmget = gsmtty_tiocmget,
3181 .tiocmset = gsmtty_tiocmset,
3182 .break_ctl = gsmtty_break_ctl,
3187 static int __init gsm_init(void)
3189 /* Fill in our line protocol discipline, and register it */
3190 int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet);
3192 pr_err("n_gsm: can't register line discipline (err = %d)\n",
3197 gsm_tty_driver = alloc_tty_driver(256);
3198 if (!gsm_tty_driver) {
3199 tty_unregister_ldisc(N_GSM0710);
3200 pr_err("gsm_init: tty allocation failed.\n");
3203 gsm_tty_driver->driver_name = "gsmtty";
3204 gsm_tty_driver->name = "gsmtty";
3205 gsm_tty_driver->major = 0; /* Dynamic */
3206 gsm_tty_driver->minor_start = 0;
3207 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
3208 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
3209 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV
3210 | TTY_DRIVER_HARDWARE_BREAK;
3211 gsm_tty_driver->init_termios = tty_std_termios;
3213 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
3214 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
3216 spin_lock_init(&gsm_mux_lock);
3218 if (tty_register_driver(gsm_tty_driver)) {
3219 put_tty_driver(gsm_tty_driver);
3220 tty_unregister_ldisc(N_GSM0710);
3221 pr_err("gsm_init: tty registration failed.\n");
3224 pr_debug("gsm_init: loaded as %d,%d.\n",
3225 gsm_tty_driver->major, gsm_tty_driver->minor_start);
3229 static void __exit gsm_exit(void)
3231 int status = tty_unregister_ldisc(N_GSM0710);
3233 pr_err("n_gsm: can't unregister line discipline (err = %d)\n",
3235 tty_unregister_driver(gsm_tty_driver);
3236 put_tty_driver(gsm_tty_driver);
3239 module_init(gsm_init);
3240 module_exit(gsm_exit);
3243 MODULE_LICENSE("GPL");
3244 MODULE_ALIAS_LDISC(N_GSM0710);