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/signal.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
93 * Created when net interface is initialized.
97 struct gsm_dlci *dlci;
101 * Each block of data we have queued to go out is in the form of
102 * a gsm_msg which holds everything we need in a link layer independent
107 struct list_head list;
108 u8 addr; /* DLCI address + flags */
109 u8 ctrl; /* Control byte + flags */
110 unsigned int len; /* Length of data block (can be zero) */
111 unsigned char *data; /* Points into buffer but not at the start */
112 unsigned char buffer[0];
116 * Each active data link has a gsm_dlci structure associated which ties
117 * the link layer to an optional tty (if the tty side is open). To avoid
118 * complexity right now these are only ever freed up when the mux is
121 * At the moment we don't free DLCI objects until the mux is torn down
122 * this avoid object life time issues but might be worth review later.
129 #define DLCI_CLOSED 0
130 #define DLCI_OPENING 1 /* Sending SABM not seen UA */
131 #define DLCI_OPEN 2 /* SABM/UA complete */
132 #define DLCI_CLOSING 3 /* Sending DISC not seen UA/DM */
137 #define DLCI_MODE_ABM 0 /* Normal Asynchronous Balanced Mode */
138 #define DLCI_MODE_ADM 1 /* Asynchronous Disconnected Mode */
139 spinlock_t lock; /* Protects the internal state */
140 struct timer_list t1; /* Retransmit timer for SABM and UA */
142 /* Uplink tty if active */
143 struct tty_port port; /* The tty bound to this DLCI if there is one */
144 struct kfifo *fifo; /* Queue fifo for the DLCI */
145 struct kfifo _fifo; /* For new fifo API porting only */
146 int adaption; /* Adaption layer in use */
148 u32 modem_rx; /* Our incoming virtual modem lines */
149 u32 modem_tx; /* Our outgoing modem lines */
150 int dead; /* Refuse re-open */
152 int throttled; /* Private copy of throttle state */
153 int constipated; /* Throttle status for outgoing */
155 struct sk_buff *skb; /* Frame being sent */
156 struct sk_buff_head skb_list; /* Queued frames */
157 /* Data handling callback */
158 void (*data)(struct gsm_dlci *dlci, u8 *data, int len);
159 void (*prev_data)(struct gsm_dlci *dlci, u8 *data, int len);
160 struct net_device *net; /* network interface, if created */
163 /* DLCI 0, 62/63 are special or reserved see gsmtty_open */
168 * DLCI 0 is used to pass control blocks out of band of the data
169 * flow (and with a higher link priority). One command can be outstanding
170 * at a time and we use this structure to manage them. They are created
171 * and destroyed by the user context, and updated by the receive paths
176 u8 cmd; /* Command we are issuing */
177 u8 *data; /* Data for the command in case we retransmit */
178 int len; /* Length of block for retransmission */
179 int done; /* Done flag */
180 int error; /* Error if any */
184 * Each GSM mux we have is represented by this structure. If we are
185 * operating as an ldisc then we use this structure as our ldisc
186 * state. We need to sort out lifetimes and locking with respect
187 * to the gsm mux array. For now we don't free DLCI objects that
188 * have been instantiated until the mux itself is terminated.
190 * To consider further: tty open versus mux shutdown.
194 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.
831 Always one byte as we never 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))
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;
1383 /* If DLCI0 is in ADM mode skip retries, it won't respond */
1384 if (gsm->dlci[0]->mode == DLCI_MODE_ADM)
1387 gsm->cretries = gsm->n2;
1389 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1390 gsm_control_transmit(gsm, ctrl);
1391 spin_unlock_irqrestore(&gsm->control_lock, flags);
1396 * gsm_control_wait - wait for a control to finish
1398 * @control: control we are waiting on
1400 * Waits for the control to complete or time out. Frees any used
1401 * resources and returns 0 for success, or an error if the remote
1402 * rejected or ignored the request.
1405 static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
1408 wait_event(gsm->event, control->done == 1);
1409 err = control->error;
1416 * DLCI level handling: Needs krefs
1420 * State transitions and timers
1424 * gsm_dlci_close - a DLCI has closed
1425 * @dlci: DLCI that closed
1427 * Perform processing when moving a DLCI into closed state. If there
1428 * is an attached tty this is hung up
1431 static void gsm_dlci_close(struct gsm_dlci *dlci)
1433 del_timer(&dlci->t1);
1435 pr_debug("DLCI %d goes closed.\n", dlci->addr);
1436 dlci->state = DLCI_CLOSED;
1437 if (dlci->addr != 0) {
1438 tty_port_tty_hangup(&dlci->port, false);
1439 kfifo_reset(dlci->fifo);
1441 dlci->gsm->dead = 1;
1442 wake_up(&dlci->gsm->event);
1443 /* A DLCI 0 close is a MUX termination so we need to kick that
1444 back to userspace somehow */
1448 * gsm_dlci_open - a DLCI has opened
1449 * @dlci: DLCI that opened
1451 * Perform processing when moving a DLCI into open state.
1454 static void gsm_dlci_open(struct gsm_dlci *dlci)
1456 /* Note that SABM UA .. SABM UA first UA lost can mean that we go
1458 del_timer(&dlci->t1);
1459 /* This will let a tty open continue */
1460 dlci->state = DLCI_OPEN;
1462 pr_debug("DLCI %d goes open.\n", dlci->addr);
1463 wake_up(&dlci->gsm->event);
1467 * gsm_dlci_t1 - T1 timer expiry
1468 * @dlci: DLCI that opened
1470 * The T1 timer handles retransmits of control frames (essentially of
1471 * SABM and DISC). We resend the command until the retry count runs out
1472 * in which case an opening port goes back to closed and a closing port
1473 * is simply put into closed state (any further frames from the other
1474 * end will get a DM response)
1476 * Some control dlci can stay in ADM mode with other dlci working just
1477 * fine. In that case we can just keep the control dlci open after the
1478 * DLCI_OPENING retries time out.
1481 static void gsm_dlci_t1(unsigned long data)
1483 struct gsm_dlci *dlci = (struct gsm_dlci *)data;
1484 struct gsm_mux *gsm = dlci->gsm;
1486 switch (dlci->state) {
1489 if (dlci->retries) {
1490 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1491 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1492 } else if (!dlci->addr && gsm->control == (DM | PF)) {
1494 pr_info("DLCI %d opening in ADM mode.\n",
1496 dlci->mode = DLCI_MODE_ADM;
1497 gsm_dlci_open(dlci);
1499 gsm_dlci_close(dlci);
1505 if (dlci->retries) {
1506 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1507 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1509 gsm_dlci_close(dlci);
1515 * gsm_dlci_begin_open - start channel open procedure
1516 * @dlci: DLCI to open
1518 * Commence opening a DLCI from the Linux side. We issue SABM messages
1519 * to the modem which should then reply with a UA or ADM, at which point
1520 * we will move into open state. Opening is done asynchronously with retry
1521 * running off timers and the responses.
1524 static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
1526 struct gsm_mux *gsm = dlci->gsm;
1527 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING)
1529 dlci->retries = gsm->n2;
1530 dlci->state = DLCI_OPENING;
1531 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1532 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1536 * gsm_dlci_begin_close - start channel open procedure
1537 * @dlci: DLCI to open
1539 * Commence closing a DLCI from the Linux side. We issue DISC messages
1540 * to the modem which should then reply with a UA, at which point we
1541 * will move into closed state. Closing is done asynchronously with retry
1542 * off timers. We may also receive a DM reply from the other end which
1543 * indicates the channel was already closed.
1546 static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
1548 struct gsm_mux *gsm = dlci->gsm;
1549 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
1551 dlci->retries = gsm->n2;
1552 dlci->state = DLCI_CLOSING;
1553 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1554 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1558 * gsm_dlci_data - data arrived
1560 * @data: block of bytes received
1561 * @len: length of received block
1563 * A UI or UIH frame has arrived which contains data for a channel
1564 * other than the control channel. If the relevant virtual tty is
1565 * open we shovel the bits down it, if not we drop them.
1568 static void gsm_dlci_data(struct gsm_dlci *dlci, u8 *data, int clen)
1571 struct tty_port *port = &dlci->port;
1572 struct tty_struct *tty;
1573 unsigned int modem = 0;
1577 pr_debug("%d bytes for tty\n", len);
1578 switch (dlci->adaption) {
1579 /* Unsupported types */
1580 /* Packetised interruptible data */
1583 /* Packetised uininterruptible voice/data */
1586 /* Asynchronous serial with line state in each frame */
1588 while (gsm_read_ea(&modem, *data++) == 0) {
1593 tty = tty_port_tty_get(port);
1595 gsm_process_modem(tty, dlci, modem, clen);
1598 /* Line state will go via DLCI 0 controls only */
1601 tty_insert_flip_string(port, data, len);
1602 tty_flip_buffer_push(port);
1607 * gsm_dlci_control - data arrived on control channel
1609 * @data: block of bytes received
1610 * @len: length of received block
1612 * A UI or UIH frame has arrived which contains data for DLCI 0 the
1613 * control channel. This should contain a command EA followed by
1614 * control data bytes. The command EA contains a command/response bit
1615 * and we divide up the work accordingly.
1618 static void gsm_dlci_command(struct gsm_dlci *dlci, u8 *data, int len)
1620 /* See what command is involved */
1621 unsigned int command = 0;
1623 if (gsm_read_ea(&command, *data++) == 1) {
1626 /* FIXME: this is properly an EA */
1628 /* Malformed command ? */
1632 gsm_control_message(dlci->gsm, command,
1635 gsm_control_response(dlci->gsm, command,
1643 * Allocate/Free DLCI channels
1647 * gsm_dlci_alloc - allocate a DLCI
1649 * @addr: address of the DLCI
1651 * Allocate and install a new DLCI object into the GSM mux.
1653 * FIXME: review locking races
1656 static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
1658 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC);
1661 spin_lock_init(&dlci->lock);
1662 mutex_init(&dlci->mutex);
1663 dlci->fifo = &dlci->_fifo;
1664 if (kfifo_alloc(&dlci->_fifo, 4096, GFP_KERNEL) < 0) {
1669 skb_queue_head_init(&dlci->skb_list);
1670 init_timer(&dlci->t1);
1671 dlci->t1.function = gsm_dlci_t1;
1672 dlci->t1.data = (unsigned long)dlci;
1673 tty_port_init(&dlci->port);
1674 dlci->port.ops = &gsm_port_ops;
1677 dlci->adaption = gsm->adaption;
1678 dlci->state = DLCI_CLOSED;
1680 dlci->data = gsm_dlci_data;
1682 dlci->data = gsm_dlci_command;
1683 gsm->dlci[addr] = dlci;
1688 * gsm_dlci_free - free DLCI
1689 * @dlci: DLCI to free
1695 static void gsm_dlci_free(struct tty_port *port)
1697 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
1699 del_timer_sync(&dlci->t1);
1700 dlci->gsm->dlci[dlci->addr] = NULL;
1701 kfifo_free(dlci->fifo);
1702 while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
1703 dev_kfree_skb(dlci->skb);
1707 static inline void dlci_get(struct gsm_dlci *dlci)
1709 tty_port_get(&dlci->port);
1712 static inline void dlci_put(struct gsm_dlci *dlci)
1714 tty_port_put(&dlci->port);
1717 static void gsm_destroy_network(struct gsm_dlci *dlci);
1720 * gsm_dlci_release - release DLCI
1721 * @dlci: DLCI to destroy
1723 * Release a DLCI. Actual free is deferred until either
1724 * mux is closed or tty is closed - whichever is last.
1728 static void gsm_dlci_release(struct gsm_dlci *dlci)
1730 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1732 mutex_lock(&dlci->mutex);
1733 gsm_destroy_network(dlci);
1734 mutex_unlock(&dlci->mutex);
1738 tty_port_tty_set(&dlci->port, NULL);
1741 dlci->state = DLCI_CLOSED;
1746 * LAPBish link layer logic
1750 * gsm_queue - a GSM frame is ready to process
1751 * @gsm: pointer to our gsm mux
1753 * At this point in time a frame has arrived and been demangled from
1754 * the line encoding. All the differences between the encodings have
1755 * been handled below us and the frame is unpacked into the structures.
1756 * The fcs holds the header FCS but any data FCS must be added here.
1759 static void gsm_queue(struct gsm_mux *gsm)
1761 struct gsm_dlci *dlci;
1764 /* We have to sneak a look at the packet body to do the FCS.
1765 A somewhat layering violation in the spec */
1767 if ((gsm->control & ~PF) == UI)
1768 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len);
1769 if (gsm->encoding == 0) {
1770 /* WARNING: gsm->received_fcs is used for
1771 gsm->encoding = 0 only.
1772 In this case it contain the last piece of data
1773 required to generate final CRC */
1774 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs);
1776 if (gsm->fcs != GOOD_FCS) {
1779 pr_debug("BAD FCS %02x\n", gsm->fcs);
1782 address = gsm->address >> 1;
1783 if (address >= NUM_DLCI)
1786 cr = gsm->address & 1; /* C/R bit */
1788 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
1790 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */
1791 dlci = gsm->dlci[address];
1793 switch (gsm->control) {
1798 dlci = gsm_dlci_alloc(gsm, address);
1802 gsm_response(gsm, address, DM);
1804 gsm_response(gsm, address, UA);
1805 gsm_dlci_open(dlci);
1811 if (dlci == NULL || dlci->state == DLCI_CLOSED) {
1812 gsm_response(gsm, address, DM);
1815 /* Real close complete */
1816 gsm_response(gsm, address, UA);
1817 gsm_dlci_close(dlci);
1821 if (cr == 0 || dlci == NULL)
1823 switch (dlci->state) {
1825 gsm_dlci_close(dlci);
1828 gsm_dlci_open(dlci);
1832 case DM: /* DM can be valid unsolicited */
1838 gsm_dlci_close(dlci);
1848 if (dlci == NULL || dlci->state != DLCI_OPEN) {
1849 gsm_command(gsm, address, DM|PF);
1852 dlci->data(dlci, gsm->buf, gsm->len);
1865 * gsm0_receive - perform processing for non-transparency
1866 * @gsm: gsm data for this ldisc instance
1869 * Receive bytes in gsm mode 0
1872 static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
1876 switch (gsm->state) {
1877 case GSM_SEARCH: /* SOF marker */
1878 if (c == GSM0_SOF) {
1879 gsm->state = GSM_ADDRESS;
1882 gsm->fcs = INIT_FCS;
1885 case GSM_ADDRESS: /* Address EA */
1886 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1887 if (gsm_read_ea(&gsm->address, c))
1888 gsm->state = GSM_CONTROL;
1890 case GSM_CONTROL: /* Control Byte */
1891 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1893 gsm->state = GSM_LEN0;
1895 case GSM_LEN0: /* Length EA */
1896 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1897 if (gsm_read_ea(&gsm->len, c)) {
1898 if (gsm->len > gsm->mru) {
1900 gsm->state = GSM_SEARCH;
1905 gsm->state = GSM_FCS;
1907 gsm->state = GSM_DATA;
1910 gsm->state = GSM_LEN1;
1913 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1915 gsm->len |= len << 7;
1916 if (gsm->len > gsm->mru) {
1918 gsm->state = GSM_SEARCH;
1923 gsm->state = GSM_FCS;
1925 gsm->state = GSM_DATA;
1927 case GSM_DATA: /* Data */
1928 gsm->buf[gsm->count++] = c;
1929 if (gsm->count == gsm->len)
1930 gsm->state = GSM_FCS;
1932 case GSM_FCS: /* FCS follows the packet */
1933 gsm->received_fcs = c;
1935 gsm->state = GSM_SSOF;
1938 if (c == GSM0_SOF) {
1939 gsm->state = GSM_SEARCH;
1947 * gsm1_receive - perform processing for non-transparency
1948 * @gsm: gsm data for this ldisc instance
1951 * Receive bytes in mode 1 (Advanced option)
1954 static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
1956 if (c == GSM1_SOF) {
1957 /* EOF is only valid in frame if we have got to the data state
1958 and received at least one byte (the FCS) */
1959 if (gsm->state == GSM_DATA && gsm->count) {
1960 /* Extract the FCS */
1962 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
1963 gsm->len = gsm->count;
1965 gsm->state = GSM_START;
1968 /* Any partial frame was a runt so go back to start */
1969 if (gsm->state != GSM_START) {
1971 gsm->state = GSM_START;
1973 /* A SOF in GSM_START means we are still reading idling or
1978 if (c == GSM1_ESCAPE) {
1983 /* Only an unescaped SOF gets us out of GSM search */
1984 if (gsm->state == GSM_SEARCH)
1988 c ^= GSM1_ESCAPE_BITS;
1991 switch (gsm->state) {
1992 case GSM_START: /* First byte after SOF */
1994 gsm->state = GSM_ADDRESS;
1995 gsm->fcs = INIT_FCS;
1997 case GSM_ADDRESS: /* Address continuation */
1998 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1999 if (gsm_read_ea(&gsm->address, c))
2000 gsm->state = GSM_CONTROL;
2002 case GSM_CONTROL: /* Control Byte */
2003 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2006 gsm->state = GSM_DATA;
2008 case GSM_DATA: /* Data */
2009 if (gsm->count > gsm->mru) { /* Allow one for the FCS */
2010 gsm->state = GSM_OVERRUN;
2013 gsm->buf[gsm->count++] = c;
2015 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */
2021 * gsm_error - handle tty error
2023 * @data: byte received (may be invalid)
2024 * @flag: error received
2026 * Handle an error in the receipt of data for a frame. Currently we just
2027 * go back to hunting for a SOF.
2029 * FIXME: better diagnostics ?
2032 static void gsm_error(struct gsm_mux *gsm,
2033 unsigned char data, unsigned char flag)
2035 gsm->state = GSM_SEARCH;
2039 static int gsm_disconnect(struct gsm_mux *gsm)
2041 struct gsm_dlci *dlci = gsm->dlci[0];
2042 struct gsm_control *gc;
2047 /* In theory disconnecting DLCI 0 is sufficient but for some
2048 modems this is apparently not the case. */
2049 gc = gsm_control_send(gsm, CMD_CLD, NULL, 0);
2051 gsm_control_wait(gsm, gc);
2053 del_timer_sync(&gsm->t2_timer);
2054 /* Now we are sure T2 has stopped */
2056 gsm_dlci_begin_close(dlci);
2057 wait_event_interruptible(gsm->event,
2058 dlci->state == DLCI_CLOSED);
2060 if (signal_pending(current))
2067 * gsm_cleanup_mux - generic GSM protocol cleanup
2070 * Clean up the bits of the mux which are the same for all framing
2071 * protocols. Remove the mux from the mux table, stop all the timers
2072 * and then shut down each device hanging up the channels as we go.
2075 static void gsm_cleanup_mux(struct gsm_mux *gsm)
2078 struct gsm_dlci *dlci = gsm->dlci[0];
2079 struct gsm_msg *txq, *ntxq;
2083 spin_lock(&gsm_mux_lock);
2084 for (i = 0; i < MAX_MUX; i++) {
2085 if (gsm_mux[i] == gsm) {
2090 spin_unlock(&gsm_mux_lock);
2091 /* open failed before registering => nothing to do */
2095 del_timer_sync(&gsm->t2_timer);
2096 /* Now we are sure T2 has stopped */
2100 /* Free up any link layer users */
2101 mutex_lock(&gsm->mutex);
2102 for (i = 0; i < NUM_DLCI; i++)
2104 gsm_dlci_release(gsm->dlci[i]);
2105 mutex_unlock(&gsm->mutex);
2106 /* Now wipe the queues */
2107 list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list)
2109 INIT_LIST_HEAD(&gsm->tx_list);
2113 * gsm_activate_mux - generic GSM setup
2116 * Set up the bits of the mux which are the same for all framing
2117 * protocols. Add the mux to the mux table so it can be opened and
2118 * finally kick off connecting to DLCI 0 on the modem.
2121 static int gsm_activate_mux(struct gsm_mux *gsm)
2123 struct gsm_dlci *dlci;
2126 setup_timer(&gsm->t2_timer, gsm_control_retransmit, (unsigned long)gsm);
2127 init_waitqueue_head(&gsm->event);
2128 spin_lock_init(&gsm->control_lock);
2129 spin_lock_init(&gsm->tx_lock);
2131 if (gsm->encoding == 0)
2132 gsm->receive = gsm0_receive;
2134 gsm->receive = gsm1_receive;
2135 gsm->error = gsm_error;
2137 spin_lock(&gsm_mux_lock);
2138 for (i = 0; i < MAX_MUX; i++) {
2139 if (gsm_mux[i] == NULL) {
2145 spin_unlock(&gsm_mux_lock);
2149 dlci = gsm_dlci_alloc(gsm, 0);
2152 gsm->dead = 0; /* Tty opens are now permissible */
2157 * gsm_free_mux - free up a mux
2160 * Dispose of allocated resources for a dead mux
2162 static void gsm_free_mux(struct gsm_mux *gsm)
2164 kfree(gsm->txframe);
2170 * gsm_free_muxr - free up a mux
2173 * Dispose of allocated resources for a dead mux
2175 static void gsm_free_muxr(struct kref *ref)
2177 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref);
2181 static inline void mux_get(struct gsm_mux *gsm)
2183 kref_get(&gsm->ref);
2186 static inline void mux_put(struct gsm_mux *gsm)
2188 kref_put(&gsm->ref, gsm_free_muxr);
2192 * gsm_alloc_mux - allocate a mux
2194 * Creates a new mux ready for activation.
2197 static struct gsm_mux *gsm_alloc_mux(void)
2199 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
2202 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL);
2203 if (gsm->buf == NULL) {
2207 gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL);
2208 if (gsm->txframe == NULL) {
2213 spin_lock_init(&gsm->lock);
2214 mutex_init(&gsm->mutex);
2215 kref_init(&gsm->ref);
2216 INIT_LIST_HEAD(&gsm->tx_list);
2224 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
2226 gsm->dead = 1; /* Avoid early tty opens */
2232 * gsmld_output - write to link
2234 * @data: bytes to output
2237 * Write a block of data from the GSM mux to the data channel. This
2238 * will eventually be serialized from above but at the moment isn't.
2241 static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
2243 if (tty_write_room(gsm->tty) < len) {
2244 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
2248 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET,
2250 gsm->tty->ops->write(gsm->tty, data, len);
2255 * gsmld_attach_gsm - mode set up
2256 * @tty: our tty structure
2259 * Set up the MUX for basic mode and commence connecting to the
2260 * modem. Currently called from the line discipline set up but
2261 * will need moving to an ioctl path.
2264 static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2268 gsm->tty = tty_kref_get(tty);
2269 gsm->output = gsmld_output;
2270 ret = gsm_activate_mux(gsm);
2272 tty_kref_put(gsm->tty);
2274 /* Don't register device 0 - this is the control channel and not
2275 a usable tty interface */
2276 base = gsm->num << 6; /* Base for this MUX */
2277 for (i = 1; i < NUM_DLCI; i++)
2278 tty_register_device(gsm_tty_driver, base + i, NULL);
2285 * gsmld_detach_gsm - stop doing 0710 mux
2286 * @tty: tty attached to the mux
2289 * Shutdown and then clean up the resources used by the line discipline
2292 static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2295 int base = gsm->num << 6; /* Base for this MUX */
2297 WARN_ON(tty != gsm->tty);
2298 for (i = 1; i < NUM_DLCI; i++)
2299 tty_unregister_device(gsm_tty_driver, base + i);
2300 gsm_cleanup_mux(gsm);
2301 tty_kref_put(gsm->tty);
2305 static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
2306 char *fp, int count)
2308 struct gsm_mux *gsm = tty->disc_data;
2309 const unsigned char *dp;
2312 char flags = TTY_NORMAL;
2315 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET,
2318 for (i = count, dp = cp, f = fp; i; i--, dp++) {
2323 gsm->receive(gsm, *dp);
2329 gsm->error(gsm, *dp, flags);
2332 WARN_ONCE(1, "%s: unknown flag %d\n",
2333 tty_name(tty), flags);
2337 /* FASYNC if needed ? */
2338 /* If clogged call tty_throttle(tty); */
2342 * gsmld_flush_buffer - clean input queue
2343 * @tty: terminal device
2345 * Flush the input buffer. Called when the line discipline is
2346 * being closed, when the tty layer wants the buffer flushed (eg
2350 static void gsmld_flush_buffer(struct tty_struct *tty)
2355 * gsmld_close - close the ldisc for this tty
2358 * Called from the terminal layer when this line discipline is
2359 * being shut down, either because of a close or becsuse of a
2360 * discipline change. The function will not be called while other
2361 * ldisc methods are in progress.
2364 static void gsmld_close(struct tty_struct *tty)
2366 struct gsm_mux *gsm = tty->disc_data;
2368 gsmld_detach_gsm(tty, gsm);
2370 gsmld_flush_buffer(tty);
2371 /* Do other clean up here */
2376 * gsmld_open - open an ldisc
2377 * @tty: terminal to open
2379 * Called when this line discipline is being attached to the
2380 * terminal device. Can sleep. Called serialized so that no
2381 * other events will occur in parallel. No further open will occur
2385 static int gsmld_open(struct tty_struct *tty)
2387 struct gsm_mux *gsm;
2390 if (tty->ops->write == NULL)
2393 /* Attach our ldisc data */
2394 gsm = gsm_alloc_mux();
2398 tty->disc_data = gsm;
2399 tty->receive_room = 65536;
2401 /* Attach the initial passive connection */
2404 ret = gsmld_attach_gsm(tty, gsm);
2406 gsm_cleanup_mux(gsm);
2413 * gsmld_write_wakeup - asynchronous I/O notifier
2416 * Required for the ptys, serial driver etc. since processes
2417 * that attach themselves to the master and rely on ASYNC
2418 * IO must be woken up
2421 static void gsmld_write_wakeup(struct tty_struct *tty)
2423 struct gsm_mux *gsm = tty->disc_data;
2424 unsigned long flags;
2427 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2428 spin_lock_irqsave(&gsm->tx_lock, flags);
2430 if (gsm->tx_bytes < TX_THRESH_LO) {
2431 gsm_dlci_data_sweep(gsm);
2433 spin_unlock_irqrestore(&gsm->tx_lock, flags);
2437 * gsmld_read - read function for tty
2439 * @file: file object
2440 * @buf: userspace buffer pointer
2443 * Perform reads for the line discipline. We are guaranteed that the
2444 * line discipline will not be closed under us but we may get multiple
2445 * parallel readers and must handle this ourselves. We may also get
2446 * a hangup. Always called in user context, may sleep.
2448 * This code must be sure never to sleep through a hangup.
2451 static ssize_t gsmld_read(struct tty_struct *tty, struct file *file,
2452 unsigned char __user *buf, size_t nr)
2458 * gsmld_write - write function for tty
2460 * @file: file object
2461 * @buf: userspace buffer pointer
2464 * Called when the owner of the device wants to send a frame
2465 * itself (or some other control data). The data is transferred
2466 * as-is and must be properly framed and checksummed as appropriate
2467 * by userspace. Frames are either sent whole or not at all as this
2468 * avoids pain user side.
2471 static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
2472 const unsigned char *buf, size_t nr)
2474 int space = tty_write_room(tty);
2476 return tty->ops->write(tty, buf, nr);
2477 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2482 * gsmld_poll - poll method for N_GSM0710
2483 * @tty: terminal device
2484 * @file: file accessing it
2487 * Called when the line discipline is asked to poll() for data or
2488 * for special events. This code is not serialized with respect to
2489 * other events save open/close.
2491 * This code must be sure never to sleep through a hangup.
2492 * Called without the kernel lock held - fine
2495 static unsigned int gsmld_poll(struct tty_struct *tty, struct file *file,
2498 unsigned int mask = 0;
2499 struct gsm_mux *gsm = tty->disc_data;
2501 poll_wait(file, &tty->read_wait, wait);
2502 poll_wait(file, &tty->write_wait, wait);
2503 if (tty_hung_up_p(file))
2505 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
2506 mask |= POLLOUT | POLLWRNORM;
2512 static int gsmld_config(struct tty_struct *tty, struct gsm_mux *gsm,
2513 struct gsm_config *c)
2516 int need_restart = 0;
2518 /* Stuff we don't support yet - UI or I frame transport, windowing */
2519 if ((c->adaption != 1 && c->adaption != 2) || c->k)
2521 /* Check the MRU/MTU range looks sane */
2522 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8)
2526 if (c->encapsulation > 1) /* Basic, advanced, no I */
2528 if (c->initiator > 1)
2530 if (c->i == 0 || c->i > 2) /* UIH and UI only */
2533 * See what is needed for reconfiguration
2537 if (c->t1 != 0 && c->t1 != gsm->t1)
2539 if (c->t2 != 0 && c->t2 != gsm->t2)
2541 if (c->encapsulation != gsm->encoding)
2543 if (c->adaption != gsm->adaption)
2546 if (c->initiator != gsm->initiator)
2548 if (c->mru != gsm->mru)
2550 if (c->mtu != gsm->mtu)
2554 * Close down what is needed, restart and initiate the new
2558 if (need_close || need_restart) {
2561 ret = gsm_disconnect(gsm);
2567 gsm_cleanup_mux(gsm);
2569 gsm->initiator = c->initiator;
2572 gsm->encoding = c->encapsulation;
2573 gsm->adaption = c->adaption;
2586 /* FIXME: We need to separate activation/deactivation from adding
2587 and removing from the mux array */
2589 gsm_activate_mux(gsm);
2590 if (gsm->initiator && need_close)
2591 gsm_dlci_begin_open(gsm->dlci[0]);
2595 static int gsmld_ioctl(struct tty_struct *tty, struct file *file,
2596 unsigned int cmd, unsigned long arg)
2598 struct gsm_config c;
2599 struct gsm_mux *gsm = tty->disc_data;
2602 case GSMIOC_GETCONF:
2603 memset(&c, 0, sizeof(c));
2604 c.adaption = gsm->adaption;
2605 c.encapsulation = gsm->encoding;
2606 c.initiator = gsm->initiator;
2609 c.t3 = 0; /* Not supported */
2611 if (gsm->ftype == UIH)
2615 pr_debug("Ftype %d i %d\n", gsm->ftype, c.i);
2619 if (copy_to_user((void *)arg, &c, sizeof(c)))
2622 case GSMIOC_SETCONF:
2623 if (copy_from_user(&c, (void *)arg, sizeof(c)))
2625 return gsmld_config(tty, gsm, &c);
2627 return n_tty_ioctl_helper(tty, file, cmd, arg);
2631 #ifdef CONFIG_COMPAT
2632 static long gsmld_compat_ioctl(struct tty_struct *tty, struct file *file,
2633 unsigned int cmd, unsigned long arg)
2635 return gsmld_ioctl(tty, file, cmd, arg);
2644 static int gsm_mux_net_open(struct net_device *net)
2646 pr_debug("%s called\n", __func__);
2647 netif_start_queue(net);
2651 static int gsm_mux_net_close(struct net_device *net)
2653 netif_stop_queue(net);
2657 static void dlci_net_free(struct gsm_dlci *dlci)
2663 dlci->adaption = dlci->prev_adaption;
2664 dlci->data = dlci->prev_data;
2665 free_netdev(dlci->net);
2668 static void net_free(struct kref *ref)
2670 struct gsm_mux_net *mux_net;
2671 struct gsm_dlci *dlci;
2673 mux_net = container_of(ref, struct gsm_mux_net, ref);
2674 dlci = mux_net->dlci;
2677 unregister_netdev(dlci->net);
2678 dlci_net_free(dlci);
2682 static inline void muxnet_get(struct gsm_mux_net *mux_net)
2684 kref_get(&mux_net->ref);
2687 static inline void muxnet_put(struct gsm_mux_net *mux_net)
2689 kref_put(&mux_net->ref, net_free);
2692 static int gsm_mux_net_start_xmit(struct sk_buff *skb,
2693 struct net_device *net)
2695 struct gsm_mux_net *mux_net = netdev_priv(net);
2696 struct gsm_dlci *dlci = mux_net->dlci;
2697 muxnet_get(mux_net);
2699 skb_queue_head(&dlci->skb_list, skb);
2700 net->stats.tx_packets++;
2701 net->stats.tx_bytes += skb->len;
2702 gsm_dlci_data_kick(dlci);
2703 /* And tell the kernel when the last transmit started. */
2704 netif_trans_update(net);
2705 muxnet_put(mux_net);
2706 return NETDEV_TX_OK;
2709 /* called when a packet did not ack after watchdogtimeout */
2710 static void gsm_mux_net_tx_timeout(struct net_device *net)
2712 /* Tell syslog we are hosed. */
2713 dev_dbg(&net->dev, "Tx timed out.\n");
2715 /* Update statistics */
2716 net->stats.tx_errors++;
2719 static void gsm_mux_rx_netchar(struct gsm_dlci *dlci,
2720 unsigned char *in_buf, int size)
2722 struct net_device *net = dlci->net;
2723 struct sk_buff *skb;
2724 struct gsm_mux_net *mux_net = netdev_priv(net);
2725 muxnet_get(mux_net);
2727 /* Allocate an sk_buff */
2728 skb = dev_alloc_skb(size + NET_IP_ALIGN);
2730 /* We got no receive buffer. */
2731 net->stats.rx_dropped++;
2732 muxnet_put(mux_net);
2735 skb_reserve(skb, NET_IP_ALIGN);
2736 skb_put_data(skb, in_buf, size);
2739 skb->protocol = htons(ETH_P_IP);
2741 /* Ship it off to the kernel */
2744 /* update out statistics */
2745 net->stats.rx_packets++;
2746 net->stats.rx_bytes += size;
2747 muxnet_put(mux_net);
2751 static void gsm_mux_net_init(struct net_device *net)
2753 static const struct net_device_ops gsm_netdev_ops = {
2754 .ndo_open = gsm_mux_net_open,
2755 .ndo_stop = gsm_mux_net_close,
2756 .ndo_start_xmit = gsm_mux_net_start_xmit,
2757 .ndo_tx_timeout = gsm_mux_net_tx_timeout,
2760 net->netdev_ops = &gsm_netdev_ops;
2762 /* fill in the other fields */
2763 net->watchdog_timeo = GSM_NET_TX_TIMEOUT;
2764 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
2765 net->type = ARPHRD_NONE;
2766 net->tx_queue_len = 10;
2770 /* caller holds the dlci mutex */
2771 static void gsm_destroy_network(struct gsm_dlci *dlci)
2773 struct gsm_mux_net *mux_net;
2775 pr_debug("destroy network interface");
2778 mux_net = netdev_priv(dlci->net);
2779 muxnet_put(mux_net);
2783 /* caller holds the dlci mutex */
2784 static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
2788 struct net_device *net;
2789 struct gsm_mux_net *mux_net;
2791 if (!capable(CAP_NET_ADMIN))
2794 /* Already in a non tty mode */
2795 if (dlci->adaption > 2)
2798 if (nc->protocol != htons(ETH_P_IP))
2799 return -EPROTONOSUPPORT;
2801 if (nc->adaption != 3 && nc->adaption != 4)
2802 return -EPROTONOSUPPORT;
2804 pr_debug("create network interface");
2807 if (nc->if_name[0] != '\0')
2808 netname = nc->if_name;
2809 net = alloc_netdev(sizeof(struct gsm_mux_net), netname,
2810 NET_NAME_UNKNOWN, gsm_mux_net_init);
2812 pr_err("alloc_netdev failed");
2815 net->mtu = dlci->gsm->mtu;
2817 net->max_mtu = dlci->gsm->mtu;
2818 mux_net = netdev_priv(net);
2819 mux_net->dlci = dlci;
2820 kref_init(&mux_net->ref);
2821 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */
2823 /* reconfigure dlci for network */
2824 dlci->prev_adaption = dlci->adaption;
2825 dlci->prev_data = dlci->data;
2826 dlci->adaption = nc->adaption;
2827 dlci->data = gsm_mux_rx_netchar;
2830 pr_debug("register netdev");
2831 retval = register_netdev(net);
2833 pr_err("network register fail %d\n", retval);
2834 dlci_net_free(dlci);
2837 return net->ifindex; /* return network index */
2840 /* Line discipline for real tty */
2841 static struct tty_ldisc_ops tty_ldisc_packet = {
2842 .owner = THIS_MODULE,
2843 .magic = TTY_LDISC_MAGIC,
2846 .close = gsmld_close,
2847 .flush_buffer = gsmld_flush_buffer,
2849 .write = gsmld_write,
2850 #ifdef CONFIG_COMPAT
2851 .compat_ioctl = gsmld_compat_ioctl,
2853 .ioctl = gsmld_ioctl,
2855 .receive_buf = gsmld_receive_buf,
2856 .write_wakeup = gsmld_write_wakeup
2865 static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk)
2868 struct gsm_control *ctrl;
2874 modembits[0] = len << 1 | EA; /* Data bytes */
2875 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */
2876 modembits[2] = gsm_encode_modem(dlci) << 1 | EA;
2878 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */
2879 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1);
2882 return gsm_control_wait(dlci->gsm, ctrl);
2885 static int gsm_carrier_raised(struct tty_port *port)
2887 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2888 struct gsm_mux *gsm = dlci->gsm;
2890 /* Not yet open so no carrier info */
2891 if (dlci->state != DLCI_OPEN)
2897 * Basic mode with control channel in ADM mode may not respond
2898 * to CMD_MSC at all and modem_rx is empty.
2900 if (gsm->encoding == 0 && gsm->dlci[0]->mode == DLCI_MODE_ADM &&
2904 return dlci->modem_rx & TIOCM_CD;
2907 static void gsm_dtr_rts(struct tty_port *port, int onoff)
2909 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2910 unsigned int modem_tx = dlci->modem_tx;
2912 modem_tx |= TIOCM_DTR | TIOCM_RTS;
2914 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
2915 if (modem_tx != dlci->modem_tx) {
2916 dlci->modem_tx = modem_tx;
2917 gsmtty_modem_update(dlci, 0);
2921 static const struct tty_port_operations gsm_port_ops = {
2922 .carrier_raised = gsm_carrier_raised,
2923 .dtr_rts = gsm_dtr_rts,
2924 .destruct = gsm_dlci_free,
2927 static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty)
2929 struct gsm_mux *gsm;
2930 struct gsm_dlci *dlci;
2931 unsigned int line = tty->index;
2932 unsigned int mux = line >> 6;
2940 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
2941 if (gsm_mux[mux] == NULL)
2943 if (line == 0 || line > 61) /* 62/63 reserved */
2948 /* If DLCI 0 is not yet fully open return an error.
2949 This is ok from a locking
2950 perspective as we don't have to worry about this
2952 mutex_lock(&gsm->mutex);
2953 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN) {
2954 mutex_unlock(&gsm->mutex);
2957 dlci = gsm->dlci[line];
2960 dlci = gsm_dlci_alloc(gsm, line);
2963 mutex_unlock(&gsm->mutex);
2966 ret = tty_port_install(&dlci->port, driver, tty);
2970 mutex_unlock(&gsm->mutex);
2975 dlci_get(gsm->dlci[0]);
2977 tty->driver_data = dlci;
2978 mutex_unlock(&gsm->mutex);
2983 static int gsmtty_open(struct tty_struct *tty, struct file *filp)
2985 struct gsm_dlci *dlci = tty->driver_data;
2986 struct tty_port *port = &dlci->port;
2989 tty_port_tty_set(port, tty);
2992 /* We could in theory open and close before we wait - eg if we get
2993 a DM straight back. This is ok as that will have caused a hangup */
2994 tty_port_set_initialized(port, 1);
2995 /* Start sending off SABM messages */
2996 gsm_dlci_begin_open(dlci);
2997 /* And wait for virtual carrier */
2998 return tty_port_block_til_ready(port, tty, filp);
3001 static void gsmtty_close(struct tty_struct *tty, struct file *filp)
3003 struct gsm_dlci *dlci = tty->driver_data;
3004 struct gsm_mux *gsm;
3008 if (dlci->state == DLCI_CLOSED)
3010 mutex_lock(&dlci->mutex);
3011 gsm_destroy_network(dlci);
3012 mutex_unlock(&dlci->mutex);
3014 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
3016 gsm_dlci_begin_close(dlci);
3017 if (tty_port_initialized(&dlci->port) && C_HUPCL(tty))
3018 tty_port_lower_dtr_rts(&dlci->port);
3019 tty_port_close_end(&dlci->port, tty);
3020 tty_port_tty_set(&dlci->port, NULL);
3024 static void gsmtty_hangup(struct tty_struct *tty)
3026 struct gsm_dlci *dlci = tty->driver_data;
3027 if (dlci->state == DLCI_CLOSED)
3029 tty_port_hangup(&dlci->port);
3030 gsm_dlci_begin_close(dlci);
3033 static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf,
3037 struct gsm_dlci *dlci = tty->driver_data;
3038 if (dlci->state == DLCI_CLOSED)
3040 /* Stuff the bytes into the fifo queue */
3041 sent = kfifo_in_locked(dlci->fifo, buf, len, &dlci->lock);
3042 /* Need to kick the channel */
3043 gsm_dlci_data_kick(dlci);
3047 static int gsmtty_write_room(struct tty_struct *tty)
3049 struct gsm_dlci *dlci = tty->driver_data;
3050 if (dlci->state == DLCI_CLOSED)
3052 return TX_SIZE - kfifo_len(dlci->fifo);
3055 static int gsmtty_chars_in_buffer(struct tty_struct *tty)
3057 struct gsm_dlci *dlci = tty->driver_data;
3058 if (dlci->state == DLCI_CLOSED)
3060 return kfifo_len(dlci->fifo);
3063 static void gsmtty_flush_buffer(struct tty_struct *tty)
3065 struct gsm_dlci *dlci = tty->driver_data;
3066 if (dlci->state == DLCI_CLOSED)
3068 /* Caution needed: If we implement reliable transport classes
3069 then the data being transmitted can't simply be junked once
3070 it has first hit the stack. Until then we can just blow it
3072 kfifo_reset(dlci->fifo);
3073 /* Need to unhook this DLCI from the transmit queue logic */
3076 static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
3078 /* The FIFO handles the queue so the kernel will do the right
3079 thing waiting on chars_in_buffer before calling us. No work
3083 static int gsmtty_tiocmget(struct tty_struct *tty)
3085 struct gsm_dlci *dlci = tty->driver_data;
3086 if (dlci->state == DLCI_CLOSED)
3088 return dlci->modem_rx;
3091 static int gsmtty_tiocmset(struct tty_struct *tty,
3092 unsigned int set, unsigned int clear)
3094 struct gsm_dlci *dlci = tty->driver_data;
3095 unsigned int modem_tx = dlci->modem_tx;
3097 if (dlci->state == DLCI_CLOSED)
3102 if (modem_tx != dlci->modem_tx) {
3103 dlci->modem_tx = modem_tx;
3104 return gsmtty_modem_update(dlci, 0);
3110 static int gsmtty_ioctl(struct tty_struct *tty,
3111 unsigned int cmd, unsigned long arg)
3113 struct gsm_dlci *dlci = tty->driver_data;
3114 struct gsm_netconfig nc;
3117 if (dlci->state == DLCI_CLOSED)
3120 case GSMIOC_ENABLE_NET:
3121 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc)))
3123 nc.if_name[IFNAMSIZ-1] = '\0';
3124 /* return net interface index or error code */
3125 mutex_lock(&dlci->mutex);
3126 index = gsm_create_network(dlci, &nc);
3127 mutex_unlock(&dlci->mutex);
3128 if (copy_to_user((void __user *)arg, &nc, sizeof(nc)))
3131 case GSMIOC_DISABLE_NET:
3132 if (!capable(CAP_NET_ADMIN))
3134 mutex_lock(&dlci->mutex);
3135 gsm_destroy_network(dlci);
3136 mutex_unlock(&dlci->mutex);
3139 return -ENOIOCTLCMD;
3143 static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old)
3145 struct gsm_dlci *dlci = tty->driver_data;
3146 if (dlci->state == DLCI_CLOSED)
3148 /* For the moment its fixed. In actual fact the speed information
3149 for the virtual channel can be propogated in both directions by
3150 the RPN control message. This however rapidly gets nasty as we
3151 then have to remap modem signals each way according to whether
3152 our virtual cable is null modem etc .. */
3153 tty_termios_copy_hw(&tty->termios, old);
3156 static void gsmtty_throttle(struct tty_struct *tty)
3158 struct gsm_dlci *dlci = tty->driver_data;
3159 if (dlci->state == DLCI_CLOSED)
3162 dlci->modem_tx &= ~TIOCM_DTR;
3163 dlci->throttled = 1;
3164 /* Send an MSC with DTR cleared */
3165 gsmtty_modem_update(dlci, 0);
3168 static void gsmtty_unthrottle(struct tty_struct *tty)
3170 struct gsm_dlci *dlci = tty->driver_data;
3171 if (dlci->state == DLCI_CLOSED)
3174 dlci->modem_tx |= TIOCM_DTR;
3175 dlci->throttled = 0;
3176 /* Send an MSC with DTR set */
3177 gsmtty_modem_update(dlci, 0);
3180 static int gsmtty_break_ctl(struct tty_struct *tty, int state)
3182 struct gsm_dlci *dlci = tty->driver_data;
3183 int encode = 0; /* Off */
3184 if (dlci->state == DLCI_CLOSED)
3187 if (state == -1) /* "On indefinitely" - we can't encode this
3190 else if (state > 0) {
3191 encode = state / 200; /* mS to encoding */
3193 encode = 0x0F; /* Best effort */
3195 return gsmtty_modem_update(dlci, encode);
3198 static void gsmtty_cleanup(struct tty_struct *tty)
3200 struct gsm_dlci *dlci = tty->driver_data;
3201 struct gsm_mux *gsm = dlci->gsm;
3204 dlci_put(gsm->dlci[0]);
3208 /* Virtual ttys for the demux */
3209 static const struct tty_operations gsmtty_ops = {
3210 .install = gsmtty_install,
3211 .open = gsmtty_open,
3212 .close = gsmtty_close,
3213 .write = gsmtty_write,
3214 .write_room = gsmtty_write_room,
3215 .chars_in_buffer = gsmtty_chars_in_buffer,
3216 .flush_buffer = gsmtty_flush_buffer,
3217 .ioctl = gsmtty_ioctl,
3218 .throttle = gsmtty_throttle,
3219 .unthrottle = gsmtty_unthrottle,
3220 .set_termios = gsmtty_set_termios,
3221 .hangup = gsmtty_hangup,
3222 .wait_until_sent = gsmtty_wait_until_sent,
3223 .tiocmget = gsmtty_tiocmget,
3224 .tiocmset = gsmtty_tiocmset,
3225 .break_ctl = gsmtty_break_ctl,
3226 .cleanup = gsmtty_cleanup,
3231 static int __init gsm_init(void)
3233 /* Fill in our line protocol discipline, and register it */
3234 int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet);
3236 pr_err("n_gsm: can't register line discipline (err = %d)\n",
3241 gsm_tty_driver = alloc_tty_driver(256);
3242 if (!gsm_tty_driver) {
3243 tty_unregister_ldisc(N_GSM0710);
3244 pr_err("gsm_init: tty allocation failed.\n");
3247 gsm_tty_driver->driver_name = "gsmtty";
3248 gsm_tty_driver->name = "gsmtty";
3249 gsm_tty_driver->major = 0; /* Dynamic */
3250 gsm_tty_driver->minor_start = 0;
3251 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
3252 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
3253 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV
3254 | TTY_DRIVER_HARDWARE_BREAK;
3255 gsm_tty_driver->init_termios = tty_std_termios;
3257 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
3258 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
3260 spin_lock_init(&gsm_mux_lock);
3262 if (tty_register_driver(gsm_tty_driver)) {
3263 put_tty_driver(gsm_tty_driver);
3264 tty_unregister_ldisc(N_GSM0710);
3265 pr_err("gsm_init: tty registration failed.\n");
3268 pr_debug("gsm_init: loaded as %d,%d.\n",
3269 gsm_tty_driver->major, gsm_tty_driver->minor_start);
3273 static void __exit gsm_exit(void)
3275 int status = tty_unregister_ldisc(N_GSM0710);
3277 pr_err("n_gsm: can't unregister line discipline (err = %d)\n",
3279 tty_unregister_driver(gsm_tty_driver);
3280 put_tty_driver(gsm_tty_driver);
3283 module_init(gsm_init);
3284 module_exit(gsm_exit);
3287 MODULE_LICENSE("GPL");
3288 MODULE_ALIAS_LDISC(N_GSM0710);