diff options
Diffstat (limited to 'drivers/tty/n_gsm.c')
| -rw-r--r-- | drivers/tty/n_gsm.c | 2763 |
1 files changed, 2763 insertions, 0 deletions
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c new file mode 100644 index 000000000000..04ef3ef0a422 --- /dev/null +++ b/drivers/tty/n_gsm.c @@ -0,0 +1,2763 @@ +/* + * n_gsm.c GSM 0710 tty multiplexor + * Copyright (c) 2009/10 Intel Corporation + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + * + * * THIS IS A DEVELOPMENT SNAPSHOT IT IS NOT A FINAL RELEASE * + * + * TO DO: + * Mostly done: ioctls for setting modes/timing + * Partly done: hooks so you can pull off frames to non tty devs + * Restart DLCI 0 when it closes ? + * Test basic encoding + * Improve the tx engine + * Resolve tx side locking by adding a queue_head and routing + * all control traffic via it + * General tidy/document + * Review the locking/move to refcounts more (mux now moved to an + * alloc/free model ready) + * Use newest tty open/close port helpers and install hooks + * What to do about power functions ? + * Termios setting and negotiation + * Do we need a 'which mux are you' ioctl to correlate mux and tty sets + * + */ + +#include <linux/types.h> +#include <linux/major.h> +#include <linux/errno.h> +#include <linux/signal.h> +#include <linux/fcntl.h> +#include <linux/sched.h> +#include <linux/interrupt.h> +#include <linux/tty.h> +#include <linux/ctype.h> +#include <linux/mm.h> +#include <linux/string.h> +#include <linux/slab.h> +#include <linux/poll.h> +#include <linux/bitops.h> +#include <linux/file.h> +#include <linux/uaccess.h> +#include <linux/module.h> +#include <linux/timer.h> +#include <linux/tty_flip.h> +#include <linux/tty_driver.h> +#include <linux/serial.h> +#include <linux/kfifo.h> +#include <linux/skbuff.h> +#include <linux/gsmmux.h> + +static int debug; +module_param(debug, int, 0600); + +#define T1 (HZ/10) +#define T2 (HZ/3) +#define N2 3 + +/* Use long timers for testing at low speed with debug on */ +#ifdef DEBUG_TIMING +#define T1 HZ +#define T2 (2 * HZ) +#endif + +/* Semi-arbitary buffer size limits. 0710 is normally run with 32-64 byte + limits so this is plenty */ +#define MAX_MRU 512 +#define MAX_MTU 512 + +/* + * Each block of data we have queued to go out is in the form of + * a gsm_msg which holds everything we need in a link layer independant + * format + */ + +struct gsm_msg { + struct gsm_msg *next; + u8 addr; /* DLCI address + flags */ + u8 ctrl; /* Control byte + flags */ + unsigned int len; /* Length of data block (can be zero) */ + unsigned char *data; /* Points into buffer but not at the start */ + unsigned char buffer[0]; +}; + +/* + * Each active data link has a gsm_dlci structure associated which ties + * the link layer to an optional tty (if the tty side is open). To avoid + * complexity right now these are only ever freed up when the mux is + * shut down. + * + * At the moment we don't free DLCI objects until the mux is torn down + * this avoid object life time issues but might be worth review later. + */ + +struct gsm_dlci { + struct gsm_mux *gsm; + int addr; + int state; +#define DLCI_CLOSED 0 +#define DLCI_OPENING 1 /* Sending SABM not seen UA */ +#define DLCI_OPEN 2 /* SABM/UA complete */ +#define DLCI_CLOSING 3 /* Sending DISC not seen UA/DM */ + + /* Link layer */ + spinlock_t lock; /* Protects the internal state */ + struct timer_list t1; /* Retransmit timer for SABM and UA */ + int retries; + /* Uplink tty if active */ + struct tty_port port; /* The tty bound to this DLCI if there is one */ + struct kfifo *fifo; /* Queue fifo for the DLCI */ + struct kfifo _fifo; /* For new fifo API porting only */ + int adaption; /* Adaption layer in use */ + u32 modem_rx; /* Our incoming virtual modem lines */ + u32 modem_tx; /* Our outgoing modem lines */ + int dead; /* Refuse re-open */ + /* Flow control */ + int throttled; /* Private copy of throttle state */ + int constipated; /* Throttle status for outgoing */ + /* Packetised I/O */ + struct sk_buff *skb; /* Frame being sent */ + struct sk_buff_head skb_list; /* Queued frames */ + /* Data handling callback */ + void (*data)(struct gsm_dlci *dlci, u8 *data, int len); +}; + +/* DLCI 0, 62/63 are special or reseved see gsmtty_open */ + +#define NUM_DLCI 64 + +/* + * DLCI 0 is used to pass control blocks out of band of the data + * flow (and with a higher link priority). One command can be outstanding + * at a time and we use this structure to manage them. They are created + * and destroyed by the user context, and updated by the receive paths + * and timers + */ + +struct gsm_control { + u8 cmd; /* Command we are issuing */ + u8 *data; /* Data for the command in case we retransmit */ + int len; /* Length of block for retransmission */ + int done; /* Done flag */ + int error; /* Error if any */ +}; + +/* + * Each GSM mux we have is represented by this structure. If we are + * operating as an ldisc then we use this structure as our ldisc + * state. We need to sort out lifetimes and locking with respect + * to the gsm mux array. For now we don't free DLCI objects that + * have been instantiated until the mux itself is terminated. + * + * To consider further: tty open versus mux shutdown. + */ + +struct gsm_mux { + struct tty_struct *tty; /* The tty our ldisc is bound to */ + spinlock_t lock; + + /* Events on the GSM channel */ + wait_queue_head_t event; + + /* Bits for GSM mode decoding */ + + /* Framing Layer */ + unsigned char *buf; + int state; +#define GSM_SEARCH 0 +#define GSM_START 1 +#define GSM_ADDRESS 2 +#define GSM_CONTROL 3 +#define GSM_LEN 4 +#define GSM_DATA 5 +#define GSM_FCS 6 +#define GSM_OVERRUN 7 + unsigned int len; + unsigned int address; + unsigned int count; + int escape; + int encoding; + u8 control; + u8 fcs; + u8 *txframe; /* TX framing buffer */ + + /* Methods for the receiver side */ + void (*receive)(struct gsm_mux *gsm, u8 ch); + void (*error)(struct gsm_mux *gsm, u8 ch, u8 flag); + /* And transmit side */ + int (*output)(struct gsm_mux *mux, u8 *data, int len); + + /* Link Layer */ + unsigned int mru; + unsigned int mtu; + int initiator; /* Did we initiate connection */ + int dead; /* Has the mux been shut down */ + struct gsm_dlci *dlci[NUM_DLCI]; + int constipated; /* Asked by remote to shut up */ + + spinlock_t tx_lock; + unsigned int tx_bytes; /* TX data outstanding */ +#define TX_THRESH_HI 8192 +#define TX_THRESH_LO 2048 + struct gsm_msg *tx_head; /* Pending data packets */ + struct gsm_msg *tx_tail; + + /* Control messages */ + struct timer_list t2_timer; /* Retransmit timer for commands */ + int cretries; /* Command retry counter */ + struct gsm_control *pending_cmd;/* Our current pending command */ + spinlock_t control_lock; /* Protects the pending command */ + + /* Configuration */ + int adaption; /* 1 or 2 supported */ + u8 ftype; /* UI or UIH */ + int t1, t2; /* Timers in 1/100th of a sec */ + int n2; /* Retry count */ + + /* Statistics (not currently exposed) */ + unsigned long bad_fcs; + unsigned long malformed; + unsigned long io_error; + unsigned long bad_size; + unsigned long unsupported; +}; + + +/* + * Mux objects - needed so that we can translate a tty index into the + * relevant mux and DLCI. + */ + +#define MAX_MUX 4 /* 256 minors */ +static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */ +static spinlock_t gsm_mux_lock; + +/* + * This section of the driver logic implements the GSM encodings + * both the basic and the 'advanced'. Reliable transport is not + * supported. + */ + +#define CR 0x02 +#define EA 0x01 +#define PF 0x10 + +/* I is special: the rest are ..*/ +#define RR 0x01 +#define UI 0x03 +#define RNR 0x05 +#define REJ 0x09 +#define DM 0x0F +#define SABM 0x2F +#define DISC 0x43 +#define UA 0x63 +#define UIH 0xEF + +/* Channel commands */ +#define CMD_NSC 0x09 +#define CMD_TEST 0x11 +#define CMD_PSC 0x21 +#define CMD_RLS 0x29 +#define CMD_FCOFF 0x31 +#define CMD_PN 0x41 +#define CMD_RPN 0x49 +#define CMD_FCON 0x51 +#define CMD_CLD 0x61 +#define CMD_SNC 0x69 +#define CMD_MSC 0x71 + +/* Virtual modem bits */ +#define MDM_FC 0x01 +#define MDM_RTC 0x02 +#define MDM_RTR 0x04 +#define MDM_IC 0x20 +#define MDM_DV 0x40 + +#define GSM0_SOF 0xF9 +#define GSM1_SOF 0x7E +#define GSM1_ESCAPE 0x7D +#define GSM1_ESCAPE_BITS 0x20 +#define XON 0x11 +#define XOFF 0x13 + +static const struct tty_port_operations gsm_port_ops; + +/* + * CRC table for GSM 0710 + */ + +static const u8 gsm_fcs8[256] = { + 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75, + 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B, + 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69, + 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67, + 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D, + 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43, + 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51, + 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F, + 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05, + 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B, + 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19, + 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17, + 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D, + 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33, + 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21, + 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F, + 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95, + 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B, + 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89, + 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87, + 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD, + 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3, + 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1, + 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF, + 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5, + 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB, + 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9, + 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7, + 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD, + 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3, + 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1, + 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF +}; + +#define INIT_FCS 0xFF +#define GOOD_FCS 0xCF + +/** + * gsm_fcs_add - update FCS + * @fcs: Current FCS + * @c: Next data + * + * Update the FCS to include c. Uses the algorithm in the specification + * notes. + */ + +static inline u8 gsm_fcs_add(u8 fcs, u8 c) +{ + return gsm_fcs8[fcs ^ c]; +} + +/** + * gsm_fcs_add_block - update FCS for a block + * @fcs: Current FCS + * @c: buffer of data + * @len: length of buffer + * + * Update the FCS to include c. Uses the algorithm in the specification + * notes. + */ + +static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len) +{ + while (len--) + fcs = gsm_fcs8[fcs ^ *c++]; + return fcs; +} + +/** + * gsm_read_ea - read a byte into an EA + * @val: variable holding value + * c: byte going into the EA + * + * Processes one byte of an EA. Updates the passed variable + * and returns 1 if the EA is now completely read + */ + +static int gsm_read_ea(unsigned int *val, u8 c) +{ + /* Add the next 7 bits into the value */ + *val <<= 7; + *val |= c >> 1; + /* Was this the last byte of the EA 1 = yes*/ + return c & EA; +} + +/** + * gsm_encode_modem - encode modem data bits + * @dlci: DLCI to encode from + * + * Returns the correct GSM encoded modem status bits (6 bit field) for + * the current status of the DLCI and attached tty object + */ + +static u8 gsm_encode_modem(const struct gsm_dlci *dlci) +{ + u8 modembits = 0; + /* FC is true flow control not modem bits */ + if (dlci->throttled) + modembits |= MDM_FC; + if (dlci->modem_tx & TIOCM_DTR) + modembits |= MDM_RTC; + if (dlci->modem_tx & TIOCM_RTS) + modembits |= MDM_RTR; + if (dlci->modem_tx & TIOCM_RI) + modembits |= MDM_IC; + if (dlci->modem_tx & TIOCM_CD) + modembits |= MDM_DV; + return modembits; +} + +/** + * gsm_print_packet - display a frame for debug + * @hdr: header to print before decode + * @addr: address EA from the frame + * @cr: C/R bit from the frame + * @control: control including PF bit + * @data: following data bytes + * @dlen: length of data + * + * Displays a packet in human readable format for debugging purposes. The + * style is based on amateur radio LAP-B dump display. + */ + +static void gsm_print_packet(const char *hdr, int addr, int cr, + u8 control, const u8 *data, int dlen) +{ + if (!(debug & 1)) + return; + + printk(KERN_INFO "%s %d) %c: ", hdr, addr, "RC"[cr]); + + switch (control & ~PF) { + case SABM: + printk(KERN_CONT "SABM"); + break; + case UA: + printk(KERN_CONT "UA"); + break; + case DISC: + printk(KERN_CONT "DISC"); + break; + case DM: + printk(KERN_CONT "DM"); + break; + case UI: + printk(KERN_CONT "UI"); + break; + case UIH: + printk(KERN_CONT "UIH"); + break; + default: + if (!(control & 0x01)) { + printk(KERN_CONT "I N(S)%d N(R)%d", + (control & 0x0E) >> 1, (control & 0xE)>> 5); + } else switch (control & 0x0F) { + case RR: + printk("RR(%d)", (control & 0xE0) >> 5); + break; + case RNR: + printk("RNR(%d)", (control & 0xE0) >> 5); + break; + case REJ: + printk("REJ(%d)", (control & 0xE0) >> 5); + break; + default: + printk(KERN_CONT "[%02X]", control); + } + } + + if (control & PF) + printk(KERN_CONT "(P)"); + else + printk(KERN_CONT "(F)"); + + if (dlen) { + int ct = 0; + while (dlen--) { + if (ct % 8 == 0) + printk(KERN_CONT "\n "); + printk(KERN_CONT "%02X ", *data++); + ct++; + } + } + printk(KERN_CONT "\n"); +} + + +/* + * Link level transmission side + */ + +/** + * gsm_stuff_packet - bytestuff a packet + * @ibuf: input + * @obuf: output + * @len: length of input + * + * Expand a buffer by bytestuffing it. The worst case size change + * is doubling and the caller is responsible for handing out + * suitable sized buffers. + */ + +static int gsm_stuff_frame(const u8 *input, u8 *output, int len) +{ + int olen = 0; + while (len--) { + if (*input == GSM1_SOF || *input == GSM1_ESCAPE + || *input == XON || *input == XOFF) { + *output++ = GSM1_ESCAPE; + *output++ = *input++ ^ GSM1_ESCAPE_BITS; + olen++; + } else + *output++ = *input++; + olen++; + } + return olen; +} + +static void hex_packet(const unsigned char *p, int len) +{ + int i; + for (i = 0; i < len; i++) { + if (i && (i % 16) == 0) + printk("\n"); + printk("%02X ", *p++); + } + printk("\n"); +} + +/** + * gsm_send - send a control frame + * @gsm: our GSM mux + * @addr: address for control frame + * @cr: command/response bit + * @control: control byte including PF bit + * + * Format up and transmit a control frame. These do not go via the + * queueing logic as they should be transmitted ahead of data when + * they are needed. + * + * FIXME: Lock versus data TX path + */ + +static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control) +{ + int len; + u8 cbuf[10]; + u8 ibuf[3]; + + switch (gsm->encoding) { + case 0: + cbuf[0] = GSM0_SOF; + cbuf[1] = (addr << 2) | (cr << 1) | EA; + cbuf[2] = control; + cbuf[3] = EA; /* Length of data = 0 */ + cbuf[4] = 0xFF - gsm_fcs_add_block(INIT_FCS, cbuf + 1, 3); + cbuf[5] = GSM0_SOF; + len = 6; + break; + case 1: + case 2: + /* Control frame + packing (but not frame stuffing) in mode 1 */ + ibuf[0] = (addr << 2) | (cr << 1) | EA; + ibuf[1] = control; + ibuf[2] = 0xFF - gsm_fcs_add_block(INIT_FCS, ibuf, 2); + /* Stuffing may double the size worst case */ + len = gsm_stuff_frame(ibuf, cbuf + 1, 3); + /* Now add the SOF markers */ + cbuf[0] = GSM1_SOF; + cbuf[len + 1] = GSM1_SOF; + /* FIXME: we can omit the lead one in many cases */ + len += 2; + break; + default: + WARN_ON(1); + return; + } + gsm->output(gsm, cbuf, len); + gsm_print_packet("-->", addr, cr, control, NULL, 0); +} + +/** + * gsm_response - send a control response + * @gsm: our GSM mux + * @addr: address for control frame + * @control: control byte including PF bit + * + * Format up and transmit a link level response frame. + */ + +static inline void gsm_response(struct gsm_mux *gsm, int addr, int control) +{ + gsm_send(gsm, addr, 0, control); +} + +/** + * gsm_command - send a control command + * @gsm: our GSM mux + * @addr: address for control frame + * @control: control byte including PF bit + * + * Format up and transmit a link level command frame. + */ + +static inline void gsm_command(struct gsm_mux *gsm, int addr, int control) +{ + gsm_send(gsm, addr, 1, control); +} + +/* Data transmission */ + +#define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */ + +/** + * gsm_data_alloc - allocate data frame + * @gsm: GSM mux + * @addr: DLCI address + * @len: length excluding header and FCS + * @ctrl: control byte + * + * Allocate a new data buffer for sending frames with data. Space is left + * at the front for header bytes but that is treated as an implementation + * detail and not for the high level code to use + */ + +static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len, + u8 ctrl) +{ + struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN, + GFP_ATOMIC); + if (m == NULL) + return NULL; + m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */ + m->len = len; + m->addr = addr; + m->ctrl = ctrl; + m->next = NULL; + return m; +} + +/** + * gsm_data_kick - poke the queue + * @gsm: GSM Mux + * + * The tty device has called us to indicate that room has appeared in + * the transmit queue. Ram more data into the pipe if we have any + * + * FIXME: lock against link layer control transmissions + */ + +static void gsm_data_kick(struct gsm_mux *gsm) +{ + struct gsm_msg *msg = gsm->tx_head; + int len; + int skip_sof = 0; + + /* FIXME: We need to apply this solely to data messages */ + if (gsm->constipated) + return; + + while (gsm->tx_head != NULL) { + msg = gsm->tx_head; + if (gsm->encoding != 0) { + gsm->txframe[0] = GSM1_SOF; + len = gsm_stuff_frame(msg->data, + gsm->txframe + 1, msg->len); + gsm->txframe[len + 1] = GSM1_SOF; + len += 2; + } else { + gsm->txframe[0] = GSM0_SOF; + memcpy(gsm->txframe + 1 , msg->data, msg->len); + gsm->txframe[msg->len + 1] = GSM0_SOF; + len = msg->len + 2; + } + + if (debug & 4) { + printk("gsm_data_kick: \n"); + hex_packet(gsm->txframe, len); + } + + if (gsm->output(gsm, gsm->txframe + skip_sof, + len - skip_sof) < 0) + break; + /* FIXME: Can eliminate one SOF in many more cases */ + gsm->tx_head = msg->next; + if (gsm->tx_head == NULL) + gsm->tx_tail = NULL; + gsm->tx_bytes -= msg->len; + kfree(msg); + /* For a burst of frames skip the extra SOF within the + burst */ + skip_sof = 1; + } +} + +/** + * __gsm_data_queue - queue a UI or UIH frame + * @dlci: DLCI sending the data + * @msg: message queued + * + * Add data to the transmit queue and try and get stuff moving + * out of the mux tty if not already doing so. The Caller must hold + * the gsm tx lock. + */ + +static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg) +{ + struct gsm_mux *gsm = dlci->gsm; + u8 *dp = msg->data; + u8 *fcs = dp + msg->len; + + /* Fill in the header */ + if (gsm->encoding == 0) { + if (msg->len < 128) + *--dp = (msg->len << 1) | EA; + else { + *--dp = (msg->len >> 6) | EA; + *--dp = (msg->len & 127) << 1; + } + } + + *--dp = msg->ctrl; + if (gsm->initiator) + *--dp = (msg->addr << 2) | 2 | EA; + else + *--dp = (msg->addr << 2) | EA; + *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp); + /* Ugly protocol layering violation */ + if (msg->ctrl == UI || msg->ctrl == (UI|PF)) + *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len); + *fcs = 0xFF - *fcs; + + gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl, + msg->data, msg->len); + + /* Move the header back and adjust the length, also allow for the FCS + now tacked on the end */ + msg->len += (msg->data - dp) + 1; + msg->data = dp; + + /* Add to the actual output queue */ + if (gsm->tx_tail) + gsm->tx_tail->next = msg; + else + gsm->tx_head = msg; + gsm->tx_tail = msg; + gsm->tx_bytes += msg->len; + gsm_data_kick(gsm); +} + +/** + * gsm_data_queue - queue a UI or UIH frame + * @dlci: DLCI sending the data + * @msg: message queued + * + * Add data to the transmit queue and try and get stuff moving + * out of the mux tty if not already doing so. Take the + * the gsm tx lock and dlci lock. + */ + +static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg) +{ + unsigned long flags; + spin_lock_irqsave(&dlci->gsm->tx_lock, flags); + __gsm_data_queue(dlci, msg); + spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags); +} + +/** + * gsm_dlci_data_output - try and push data out of a DLCI + * @gsm: mux + * @dlci: the DLCI to pull data from + * + * Pull data from a DLCI and send it into the transmit queue if there + * is data. Keep to the MRU of the mux. This path handles the usual tty + * interface which is a byte stream with optional modem data. + * + * Caller must hold the tx_lock of the mux. + */ + +static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci) +{ + struct gsm_msg *msg; + u8 *dp; + int len, size; + int h = dlci->adaption - 1; + + len = kfifo_len(dlci->fifo); + if (len == 0) + return 0; + + /* MTU/MRU count only the data bits */ + if (len > gsm->mtu) + len = gsm->mtu; + + size = len + h; + + msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype); + /* FIXME: need a timer or something to kick this so it can't + get stuck with no work outstanding and no buffer free */ + if (msg == NULL) + return -ENOMEM; + dp = msg->data; + switch (dlci->adaption) { + case 1: /* Unstructured */ + break; + case 2: /* Unstructed with modem bits. Always one byte as we never + send inline break data */ + *dp += gsm_encode_modem(dlci); + len--; + break; + } + WARN_ON(kfifo_out_locked(dlci->fifo, dp , len, &dlci->lock) != len); + __gsm_data_queue(dlci, msg); + /* Bytes of data we used up */ + return size; +} + +/** + * gsm_dlci_data_output_framed - try and push data out of a DLCI + * @gsm: mux + * @dlci: the DLCI to pull data from + * + * Pull data from a DLCI and send it into the transmit queue if there + * is data. Keep to the MRU of the mux. This path handles framed data + * queued as skbuffs to the DLCI. + * + * Caller must hold the tx_lock of the mux. + */ + +static int gsm_dlci_data_output_framed(struct gsm_mux *gsm, + struct gsm_dlci *dlci) +{ + struct gsm_msg *msg; + u8 *dp; + int len, size; + int last = 0, first = 0; + int overhead = 0; + + /* One byte per frame is used for B/F flags */ + if (dlci->adaption == 4) + overhead = 1; + + /* dlci->skb is locked by tx_lock */ + if (dlci->skb == NULL) { + dlci->skb = skb_dequeue(&dlci->skb_list); + if (dlci->skb == NULL) + return 0; + first = 1; + } + len = dlci->skb->len + overhead; + + /* MTU/MRU count only the data bits */ + if (len > gsm->mtu) { + if (dlci->adaption == 3) { + /* Over long frame, bin it */ + kfree_skb(dlci->skb); + dlci->skb = NULL; + return 0; + } + len = gsm->mtu; + } else + last = 1; + + size = len + overhead; + msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype); + + /* FIXME: need a timer or something to kick this so it can't + get stuck with no work outstanding and no buffer free */ + if (msg == NULL) + return -ENOMEM; + dp = msg->data; + + if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */ + /* Flag byte to carry the start/end info */ + *dp++ = last << 7 | first << 6 | 1; /* EA */ + len--; + } + memcpy(dp, skb_pull(dlci->skb, len), len); + __gsm_data_queue(dlci, msg); + if (last) + dlci->skb = NULL; + return size; +} + +/** + * gsm_dlci_data_sweep - look for data to send + * @gsm: the GSM mux + * + * Sweep the GSM mux channels in priority order looking for ones with + * data to send. We could do with optimising this scan a bit. We aim + * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit + * TX_THRESH_LO we get called again + * + * FIXME: We should round robin between groups and in theory you can + * renegotiate DLCI priorities with optional stuff. Needs optimising. + */ + +static void gsm_dlci_data_sweep(struct gsm_mux *gsm) +{ + int len; + /* Priority ordering: We should do priority with RR of the groups */ + int i = 1; + + while (i < NUM_DLCI) { + struct gsm_dlci *dlci; + + if (gsm->tx_bytes > TX_THRESH_HI) + break; + dlci = gsm->dlci[i]; + if (dlci == NULL || dlci->constipated) { + i++; + continue; + } + if (dlci->adaption < 3) + len = gsm_dlci_data_output(gsm, dlci); + else + len = gsm_dlci_data_output_framed(gsm, dlci); + if (len < 0) + break; + /* DLCI empty - try the next */ + if (len == 0) + i++; + } +} + +/** + * gsm_dlci_data_kick - transmit if possible + * @dlci: DLCI to kick + * + * Transmit data from this DLCI if the queue is empty. We can't rely on + * a tty wakeup except when we filled the pipe so we need to fire off + * new data ourselves in other cases. + */ + +static void gsm_dlci_data_kick(struct gsm_dlci *dlci) +{ + unsigned long flags; + + spin_lock_irqsave(&dlci->gsm->tx_lock, flags); + /* If we have nothing running then we need to fire up */ + if (dlci->gsm->tx_bytes == 0) + gsm_dlci_data_output(dlci->gsm, dlci); + else if (dlci->gsm->tx_bytes < TX_THRESH_LO) + gsm_dlci_data_sweep(dlci->gsm); + spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags); +} + +/* + * Control message processing + */ + + +/** + * gsm_control_reply - send a response frame to a control + * @gsm: gsm channel + * @cmd: the command to use + * @data: data to follow encoded info + * @dlen: length of data + * + * Encode up and queue a UI/UIH frame containing our response. + */ + +static void gsm_control_reply(struct gsm_mux *gsm, int cmd, u8 *data, + int dlen) +{ + struct gsm_msg *msg; + msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype); + msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */ + msg->data[1] = (dlen << 1) | EA; + memcpy(msg->data + 2, data, dlen); + gsm_data_queue(gsm->dlci[0], msg); +} + +/** + * gsm_process_modem - process received modem status + * @tty: virtual tty bound to the DLCI + * @dlci: DLCI to affect + * @modem: modem bits (full EA) + * + * Used when a modem control message or line state inline in adaption + * layer 2 is processed. Sort out the local modem state and throttles + */ + +static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci, + u32 modem) +{ + int mlines = 0; + u8 brk = modem >> 6; + + /* Flow control/ready to communicate */ + if (modem & MDM_FC) { + /* Need to throttle our output on this device */ + dlci->constipated = 1; + } + if (modem & MDM_RTC) { + mlines |= TIOCM_DSR | TIOCM_DTR; + dlci->constipated = 0; + gsm_dlci_data_kick(dlci); + } + /* Map modem bits */ + if (modem & MDM_RTR) + mlines |= TIOCM_RTS | TIOCM_CTS; + if (modem & MDM_IC) + mlines |= TIOCM_RI; + if (modem & MDM_DV) + mlines |= TIOCM_CD; + + /* Carrier drop -> hangup */ + if (tty) { + if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD)) + if (!(tty->termios->c_cflag & CLOCAL)) + tty_hangup(tty); + if (brk & 0x01) + tty_insert_flip_char(tty, 0, TTY_BREAK); + } + dlci->modem_rx = mlines; +} + +/** + * gsm_control_modem - modem status received + * @gsm: GSM channel + * @data: data following command + * @clen: command length + * + * We have received a modem status control message. This is used by + * the GSM mux protocol to pass virtual modem line status and optionally + * to indicate break signals. Unpack it, convert to Linux representation + * and if need be stuff a break message down the tty. + */ + +static void gsm_control_modem(struct gsm_mux *gsm, u8 *data, int clen) +{ + unsigned int addr = 0; + unsigned int modem = 0; + struct gsm_dlci *dlci; + int len = clen; + u8 *dp = data; + struct tty_struct *tty; + + while (gsm_read_ea(&addr, *dp++) == 0) { + len--; + if (len == 0) + return; + } + /* Must be at least one byte following the EA */ + len--; + if (len <= 0) + return; + + addr >>= 1; + /* Closed port, or invalid ? */ + if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL) + return; + dlci = gsm->dlci[addr]; + + while (gsm_read_ea(&modem, *dp++) == 0) { + len--; + if (len == 0) + return; + } + tty = tty_port_tty_get(&dlci->port); + gsm_process_modem(tty, dlci, modem); + if (tty) { + tty_wakeup(tty); + tty_kref_put(tty); + } + gsm_control_reply(gsm, CMD_MSC, data, clen); +} + +/** + * gsm_control_rls - remote line status + * @gsm: GSM channel + * @data: data bytes + * @clen: data length + * + * The modem sends us a two byte message on the control channel whenever + * it wishes to send us an error state from the virtual link. Stuff + * this into the uplink tty if present + */ + +static void gsm_control_rls(struct gsm_mux *gsm, u8 *data, int clen) +{ + struct tty_struct *tty; + unsigned int addr = 0 ; + u8 bits; + int len = clen; + u8 *dp = data; + + while (gsm_read_ea(&addr, *dp++) == 0) { + len--; + if (len == 0) + return; + } + /* Must be at least one byte following ea */ + len--; + if (len <= 0) + return; + addr >>= 1; + /* Closed port, or invalid ? */ + if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL) + return; + /* No error ? */ + bits = *dp; + if ((bits & 1) == 0) + return; + /* See if we have an uplink tty */ + tty = tty_port_tty_get(&gsm->dlci[addr]->port); + + if (tty) { + if (bits & 2) + tty_insert_flip_char(tty, 0, TTY_OVERRUN); + if (bits & 4) + tty_insert_flip_char(tty, 0, TTY_PARITY); + if (bits & 8) + tty_insert_flip_char(tty, 0, TTY_FRAME); + tty_flip_buffer_push(tty); + tty_kref_put(tty); + } + gsm_control_reply(gsm, CMD_RLS, data, clen); +} + +static void gsm_dlci_begin_close(struct gsm_dlci *dlci); + +/** + * gsm_control_message - DLCI 0 control processing + * @gsm: our GSM mux + * @command: the command EA + * @data: data beyond the command/length EAs + * @clen: length + * + * Input processor for control messages from the other end of the link. + * Processes the incoming request and queues a response frame or an + * NSC response if not supported + */ + +static void gsm_control_message(struct gsm_mux *gsm, unsigned int command, + u8 *data, int clen) +{ + u8 buf[1]; + switch (command) { + case CMD_CLD: { + struct gsm_dlci *dlci = gsm->dlci[0]; + /* Modem wishes to close down */ + if (dlci) { + dlci->dead = 1; + gsm->dead = 1; + gsm_dlci_begin_close(dlci); + } + } + break; + case CMD_TEST: + /* Modem wishes to test, reply with the data */ + gsm_control_reply(gsm, CMD_TEST, data, clen); + break; + case CMD_FCON: + /* Modem wants us to STFU */ + gsm->constipated = 1; + gsm_control_reply(gsm, CMD_FCON, NULL, 0); + break; + case CMD_FCOFF: + /* Modem can accept data again */ + gsm->constipated = 0; + gsm_control_reply(gsm, CMD_FCOFF, NULL, 0); + /* Kick the link in case it is idling */ + gsm_data_kick(gsm); + break; + case CMD_MSC: + /* Out of band modem line change indicator for a DLCI */ + gsm_control_modem(gsm, data, clen); + break; + case CMD_RLS: + /* Out of band error reception for a DLCI */ + gsm_control_rls(gsm, data, clen); + break; + case CMD_PSC: + /* Modem wishes to enter power saving state */ + gsm_control_reply(gsm, CMD_PSC, NULL, 0); + break; + /* Optional unsupported commands */ + case CMD_PN: /* Parameter negotiation */ + case CMD_RPN: /* Remote port negotation */ + case CMD_SNC: /* Service negotation command */ + default: + /* Reply to bad commands with an NSC */ + buf[0] = command; + gsm_control_reply(gsm, CMD_NSC, buf, 1); + break; + } +} + +/** + * gsm_control_response - process a response to our control + * @gsm: our GSM mux + * @command: the command (response) EA + * @data: data beyond the command/length EA + * @clen: length + * + * Process a response to an outstanding command. We only allow a single + * control message in flight so this is fairly easy. All the clean up + * is done by the caller, we just update the fields, flag it as done + * and return + */ + +static void gsm_control_response(struct gsm_mux *gsm, unsigned int command, + u8 *data, int clen) +{ + struct gsm_control *ctrl; + unsigned long flags; + + spin_lock_irqsave(&gsm->control_lock, flags); + + ctrl = gsm->pending_cmd; + /* Does the reply match our command */ + command |= 1; + if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) { + /* Our command was replied to, kill the retry timer */ + del_timer(&gsm->t2_timer); + gsm->pending_cmd = NULL; + /* Rejected by the other end */ + if (command == CMD_NSC) + ctrl->error = -EOPNOTSUPP; + ctrl->done = 1; + wake_up(&gsm->event); + } + spin_unlock_irqrestore(&gsm->control_lock, flags); +} + +/** + * gsm_control_transmit - send control packet + * @gsm: gsm mux + * @ctrl: frame to send + * + * Send out a pending control command (called under control lock) + */ + +static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl) +{ + struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, + gsm->ftype|PF); + if (msg == NULL) + return; + msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */ + memcpy(msg->data + 1, ctrl->data, ctrl->len); + gsm_data_queue(gsm->dlci[0], msg); +} + +/** + * gsm_control_retransmit - retransmit a control frame + * @data: pointer to our gsm object + * + * Called off the T2 timer expiry in order to retransmit control frames + * that have been lost in the system somewhere. The control_lock protects + * us from colliding with another sender or a receive completion event. + * In that situation the timer may still occur in a small window but + * gsm->pending_cmd will be NULL and we just let the timer expire. + */ + +static void gsm_control_retransmit(unsigned long data) +{ + struct gsm_mux *gsm = (struct gsm_mux *)data; + struct gsm_control *ctrl; + unsigned long flags; + spin_lock_irqsave(&gsm->control_lock, flags); + ctrl = gsm->pending_cmd; + if (ctrl) { + gsm->cretries--; + if (gsm->cretries == 0) { + gsm->pending_cmd = NULL; + ctrl->error = -ETIMEDOUT; + ctrl->done = 1; + spin_unlock_irqrestore(&gsm->control_lock, flags); + wake_up(&gsm->event); + return; + } + gsm_control_transmit(gsm, ctrl); + mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100); + } + spin_unlock_irqrestore(&gsm->control_lock, flags); +} + +/** + * gsm_control_send - send a control frame on DLCI 0 + * @gsm: the GSM channel + * @command: command to send including CR bit + * @data: bytes of data (must be kmalloced) + * @len: length of the block to send + * + * Queue and dispatch a control command. Only one command can be + * active at a time. In theory more can be outstanding but the matching + * gets really complicated so for now stick to one outstanding. + */ + +static struct gsm_control *gsm_control_send(struct gsm_mux *gsm, + unsigned int command, u8 *data, int clen) +{ + struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control), + GFP_KERNEL); + unsigned long flags; + if (ctrl == NULL) + return NULL; +retry: + wait_event(gsm->event, gsm->pending_cmd == NULL); + spin_lock_irqsave(&gsm->control_lock, flags); + if (gsm->pending_cmd != NULL) { + spin_unlock_irqrestore(&gsm->control_lock, flags); + goto retry; + } + ctrl->cmd = command; + ctrl->data = data; + ctrl->len = clen; + gsm->pending_cmd = ctrl; + gsm->cretries = gsm->n2; + mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100); + gsm_control_transmit(gsm, ctrl); + spin_unlock_irqrestore(&gsm->control_lock, flags); + return ctrl; +} + +/** + * gsm_control_wait - wait for a control to finish + * @gsm: GSM mux + * @control: control we are waiting on + * + * Waits for the control to complete or time out. Frees any used + * resources and returns 0 for success, or an error if the remote + * rejected or ignored the request. + */ + +static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control) +{ + int err; + wait_event(gsm->event, control->done == 1); + err = control->error; + kfree(control); + return err; +} + + +/* + * DLCI level handling: Needs krefs + */ + +/* + * State transitions and timers + */ + +/** + * gsm_dlci_close - a DLCI has closed + * @dlci: DLCI that closed + * + * Perform processing when moving a DLCI into closed state. If there + * is an attached tty this is hung up + */ + +static void gsm_dlci_close(struct gsm_dlci *dlci) +{ + del_timer(&dlci->t1); + if (debug & 8) + printk("DLCI %d goes closed.\n", dlci->addr); + dlci->state = DLCI_CLOSED; + if (dlci->addr != 0) { + struct tty_struct *tty = tty_port_tty_get(&dlci->port); + if (tty) { + tty_hangup(tty); + tty_kref_put(tty); + } + kfifo_reset(dlci->fifo); + } else + dlci->gsm->dead = 1; + wake_up(&dlci->gsm->event); + /* A DLCI 0 close is a MUX termination so we need to kick that + back to userspace somehow */ +} + +/** + * gsm_dlci_open - a DLCI has opened + * @dlci: DLCI that opened + * + * Perform processing when moving a DLCI into open state. + */ + +static void gsm_dlci_open(struct gsm_dlci *dlci) +{ + /* Note that SABM UA .. SABM UA first UA lost can mean that we go + open -> open */ + del_timer(&dlci->t1); + /* This will let a tty open continue */ + dlci->state = DLCI_OPEN; + if (debug & 8) + printk("DLCI %d goes open.\n", dlci->addr); + wake_up(&dlci->gsm->event); +} + +/** + * gsm_dlci_t1 - T1 timer expiry + * @dlci: DLCI that opened + * + * The T1 timer handles retransmits of control frames (essentially of + * SABM and DISC). We resend the command until the retry count runs out + * in which case an opening port goes back to closed and a closing port + * is simply put into closed state (any further frames from the other + * end will get a DM response) + */ + +static void gsm_dlci_t1(unsigned long data) +{ + struct gsm_dlci *dlci = (struct gsm_dlci *)data; + struct gsm_mux *gsm = dlci->gsm; + + switch (dlci->state) { + case DLCI_OPENING: + dlci->retries--; + if (dlci->retries) { + gsm_command(dlci->gsm, dlci->addr, SABM|PF); + mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); + } else + gsm_dlci_close(dlci); + break; + case DLCI_CLOSING: + dlci->retries--; + if (dlci->retries) { + gsm_command(dlci->gsm, dlci->addr, DISC|PF); + mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); + } else + gsm_dlci_close(dlci); + break; + } +} + +/** + * gsm_dlci_begin_open - start channel open procedure + * @dlci: DLCI to open + * + * Commence opening a DLCI from the Linux side. We issue SABM messages + * to the modem which should then reply with a UA, at which point we + * will move into open state. Opening is done asynchronously with retry + * running off timers and the responses. + */ + +static void gsm_dlci_begin_open(struct gsm_dlci *dlci) +{ + struct gsm_mux *gsm = dlci->gsm; + if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING) + return; + dlci->retries = gsm->n2; + dlci->state = DLCI_OPENING; + gsm_command(dlci->gsm, dlci->addr, SABM|PF); + mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); +} + +/** + * gsm_dlci_begin_close - start channel open procedure + * @dlci: DLCI to open + * + * Commence closing a DLCI from the Linux side. We issue DISC messages + * to the modem which should then reply with a UA, at which point we + * will move into closed state. Closing is done asynchronously with retry + * off timers. We may also receive a DM reply from the other end which + * indicates the channel was already closed. + */ + +static void gsm_dlci_begin_close(struct gsm_dlci *dlci) +{ + struct gsm_mux *gsm = dlci->gsm; + if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING) + return; + dlci->retries = gsm->n2; + dlci->state = DLCI_CLOSING; + gsm_command(dlci->gsm, dlci->addr, DISC|PF); + mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); +} + +/** + * gsm_dlci_data - data arrived + * @dlci: channel + * @data: block of bytes received + * @len: length of received block + * + * A UI or UIH frame has arrived which contains data for a channel + * other than the control channel. If the relevant virtual tty is + * open we shovel the bits down it, if not we drop them. + */ + +static void gsm_dlci_data(struct gsm_dlci *dlci, u8 *data, int len) +{ + /* krefs .. */ + struct tty_port *port = &dlci->port; + struct tty_struct *tty = tty_port_tty_get(port); + unsigned int modem = 0; + + if (debug & 16) + printk("%d bytes for tty %p\n", len, tty); + if (tty) { + switch (dlci->adaption) { + /* Unsupported types */ + /* Packetised interruptible data */ + case 4: + break; + /* Packetised uininterruptible voice/data */ + case 3: + break; + /* Asynchronous serial with line state in each frame */ + case 2: + while (gsm_read_ea(&modem, *data++) == 0) { + len--; + if (len == 0) + return; + } + gsm_process_modem(tty, dlci, modem); + /* Line state will go via DLCI 0 controls only */ + case 1: + default: + tty_insert_flip_string(tty, data, len); + tty_flip_buffer_push(tty); + } + tty_kref_put(tty); + } +} + +/** + * gsm_dlci_control - data arrived on control channel + * @dlci: channel + * @data: block of bytes received + * @len: length of received block + * + * A UI or UIH frame has arrived which contains data for DLCI 0 the + * control channel. This should contain a command EA followed by + * control data bytes. The command EA contains a command/response bit + * and we divide up the work accordingly. + */ + +static void gsm_dlci_command(struct gsm_dlci *dlci, u8 *data, int len) +{ + /* See what command is involved */ + unsigned int command = 0; + while (len-- > 0) { + if (gsm_read_ea(&command, *data++) == 1) { + int clen = *data++; + len--; + /* FIXME: this is properly an EA */ + clen >>= 1; + /* Malformed command ? */ + if (clen > len) + return; + if (command & 1) + gsm_control_message(dlci->gsm, command, + data, clen); + else + gsm_control_response(dlci->gsm, command, + data, clen); + return; + } + } +} + +/* + * Allocate/Free DLCI channels + */ + +/** + * gsm_dlci_alloc - allocate a DLCI + * @gsm: GSM mux + * @addr: address of the DLCI + * + * Allocate and install a new DLCI object into the GSM mux. + * + * FIXME: review locking races + */ + +static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr) +{ + struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC); + if (dlci == NULL) + return NULL; + spin_lock_init(&dlci->lock); + dlci->fifo = &dlci->_fifo; + if (kfifo_alloc(&dlci->_fifo, 4096, GFP_KERNEL) < 0) { + kfree(dlci); + return NULL; + } + + skb_queue_head_init(&dlci->skb_list); + init_timer(&dlci->t1); + dlci->t1.function = gsm_dlci_t1; + dlci->t1.data = (unsigned long)dlci; + tty_port_init(&dlci->port); + dlci->port.ops = &gsm_port_ops; + dlci->gsm = gsm; + dlci->addr = addr; + dlci->adaption = gsm->adaption; + dlci->state = DLCI_CLOSED; + if (addr) + dlci->data = gsm_dlci_data; + else + dlci->data = gsm_dlci_command; + gsm->dlci[addr] = dlci; + return dlci; +} + +/** + * gsm_dlci_free - release DLCI + * @dlci: DLCI to destroy + * + * Free up a DLCI. Currently to keep the lifetime rules sane we only + * clean up DLCI objects when the MUX closes rather than as the port + * is closed down on both the tty and mux levels. + * + * Can sleep. + */ +static void gsm_dlci_free(struct gsm_dlci *dlci) +{ + struct tty_struct *tty = tty_port_tty_get(&dlci->port); + if (tty) { + tty_vhangup(tty); + tty_kref_put(tty); + } + del_timer_sync(&dlci->t1); + dlci->gsm->dlci[dlci->addr] = NULL; + kfifo_free(dlci->fifo); + kfree(dlci); +} + + +/* + * LAPBish link layer logic + */ + +/** + * gsm_queue - a GSM frame is ready to process + * @gsm: pointer to our gsm mux + * + * At this point in time a frame has arrived and been demangled from + * the line encoding. All the differences between the encodings have + * been handled below us and the frame is unpacked into the structures. + * The fcs holds the header FCS but any data FCS must be added here. + */ + +static void gsm_queue(struct gsm_mux *gsm) +{ + struct gsm_dlci *dlci; + u8 cr; + int address; + /* We have to sneak a look at the packet body to do the FCS. + A somewhat layering violation in the spec */ + + if ((gsm->control & ~PF) == UI) + gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len); + if (gsm->fcs != GOOD_FCS) { + gsm->bad_fcs++; + if (debug & 4) + printk("BAD FCS %02x\n", gsm->fcs); + return; + } + address = gsm->address >> 1; + if (address >= NUM_DLCI) + goto invalid; + + cr = gsm->address & 1; /* C/R bit */ + + gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len); + + cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */ + dlci = gsm->dlci[address]; + + switch (gsm->control) { + case SABM|PF: + if (cr == 0) + goto invalid; + if (dlci == NULL) + dlci = gsm_dlci_alloc(gsm, address); + if (dlci == NULL) + return; + if (dlci->dead) + gsm_response(gsm, address, DM); + else { + gsm_response(gsm, address, UA); + gsm_dlci_open(dlci); + } + break; + case DISC|PF: + if (cr == 0) + goto invalid; + if (dlci == NULL || dlci->state == DLCI_CLOSED) { + gsm_response(gsm, address, DM); + return; + } + /* Real close complete */ + gsm_response(gsm, address, UA); + gsm_dlci_close(dlci); + break; + case UA: + case UA|PF: + if (cr == 0 || dlci == NULL) + break; + switch (dlci->state) { + case DLCI_CLOSING: + gsm_dlci_close(dlci); + break; + case DLCI_OPENING: + gsm_dlci_open(dlci); + break; + } + break; + case DM: /* DM can be valid unsolicited */ + case DM|PF: + if (cr) + goto invalid; + if (dlci == NULL) + return; + gsm_dlci_close(dlci); + break; + case UI: + case UI|PF: + case UIH: + case UIH|PF: +#if 0 + if (cr) + goto invalid; +#endif + if (dlci == NULL || dlci->state != DLCI_OPEN) { + gsm_command(gsm, address, DM|PF); + return; + } + dlci->data(dlci, gsm->buf, gsm->len); + break; + default: + goto invalid; + } + return; +invalid: + gsm->malformed++; + return; +} + + +/** + * gsm0_receive - perform processing for non-transparency + * @gsm: gsm data for this ldisc instance + * @c: character + * + * Receive bytes in gsm mode 0 + */ + +static void gsm0_receive(struct gsm_mux *gsm, unsigned char c) +{ + switch (gsm->state) { + case GSM_SEARCH: /* SOF marker */ + if (c == GSM0_SOF) { + gsm->state = GSM_ADDRESS; + gsm->address = 0; + gsm->len = 0; + gsm->fcs = INIT_FCS; + } + break; /* Address EA */ + case GSM_ADDRESS: + gsm->fcs = gsm_fcs_add(gsm->fcs, c); + if (gsm_read_ea(&gsm->address, c)) + gsm->state = GSM_CONTROL; + break; + case GSM_CONTROL: /* Control Byte */ + gsm->fcs = gsm_fcs_add(gsm->fcs, c); + gsm->control = c; + gsm->state = GSM_LEN; + break; + case GSM_LEN: /* Length EA */ + gsm->fcs = gsm_fcs_add(gsm->fcs, c); + if (gsm_read_ea(&gsm->len, c)) { + if (gsm->len > gsm->mru) { + gsm->bad_size++; + gsm->state = GSM_SEARCH; + break; + } + gsm->count = 0; + gsm->state = GSM_DATA; + } + break; + case GSM_DATA: /* Data */ + gsm->buf[gsm->count++] = c; + if (gsm->count == gsm->len) + gsm->state = GSM_FCS; + break; + case GSM_FCS: /* FCS follows the packet */ + gsm->fcs = c; + gsm_queue(gsm); + /* And then back for the next frame */ + gsm->state = GSM_SEARCH; + break; + } +} + +/** + * gsm0_receive - perform processing for non-transparency + * @gsm: gsm data for this ldisc instance + * @c: character + * + * Receive bytes in mode 1 (Advanced option) + */ + +static void gsm1_receive(struct gsm_mux *gsm, unsigned char c) +{ + if (c == GSM1_SOF) { + /* EOF is only valid in frame if we have got to the data state + and received at least one byte (the FCS) */ + if (gsm->state == GSM_DATA && gsm->count) { + /* Extract the FCS */ + gsm->count--; + gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]); + gsm->len = gsm->count; + gsm_queue(gsm); + gsm->state = GSM_START; + return; + } + /* Any partial frame was a runt so go back to start */ + if (gsm->state != GSM_START) { + gsm->malformed++; + gsm->state = GSM_START; + } + /* A SOF in GSM_START means we are still reading idling or + framing bytes */ + return; + } + + if (c == GSM1_ESCAPE) { + gsm->escape = 1; + return; + } + + /* Only an unescaped SOF gets us out of GSM search */ + if (gsm->state == GSM_SEARCH) + return; + + if (gsm->escape) { + c ^= GSM1_ESCAPE_BITS; + gsm->escape = 0; + } + switch (gsm->state) { + case GSM_START: /* First byte after SOF */ + gsm->address = 0; + gsm->state = GSM_ADDRESS; + gsm->fcs = INIT_FCS; + /* Drop through */ + case GSM_ADDRESS: /* Address continuation */ + gsm->fcs = gsm_fcs_add(gsm->fcs, c); + if (gsm_read_ea(&gsm->address, c)) + gsm->state = GSM_CONTROL; + break; + case GSM_CONTROL: /* Control Byte */ + gsm->fcs = gsm_fcs_add(gsm->fcs, c); + gsm->control = c; + gsm->count = 0; + gsm->state = GSM_DATA; + break; + case GSM_DATA: /* Data */ + if (gsm->count > gsm->mru ) { /* Allow one for the FCS */ + gsm->state = GSM_OVERRUN; + gsm->bad_size++; + } else + gsm->buf[gsm->count++] = c; + break; + case GSM_OVERRUN: /* Over-long - eg a dropped SOF */ + break; + } +} + +/** + * gsm_error - handle tty error + * @gsm: ldisc data + * @data: byte received (may be invalid) + * @flag: error received + * + * Handle an error in the receipt of data for a frame. Currently we just + * go back to hunting for a SOF. + * + * FIXME: better diagnostics ? + */ + +static void gsm_error(struct gsm_mux *gsm, + unsigned char data, unsigned char flag) +{ + gsm->state = GSM_SEARCH; + gsm->io_error++; +} + +/** + * gsm_cleanup_mux - generic GSM protocol cleanup + * @gsm: our mux + * + * Clean up the bits of the mux which are the same for all framing + * protocols. Remove the mux from the mux table, stop all the timers + * and then shut down each device hanging up the channels as we go. + */ + +void gsm_cleanup_mux(struct gsm_mux *gsm) +{ + int i; + struct gsm_dlci *dlci = gsm->dlci[0]; + struct gsm_msg *txq; + + gsm->dead = 1; + + spin_lock(&gsm_mux_lock); + for (i = 0; i < MAX_MUX; i++) { + if (gsm_mux[i] == gsm) { + gsm_mux[i] = NULL; + break; + } + } + spin_unlock(&gsm_mux_lock); + WARN_ON(i == MAX_MUX); + + del_timer_sync(&gsm->t2_timer); + /* Now we are sure T2 has stopped */ + if (dlci) { + dlci->dead = 1; + gsm_dlci_begin_close(dlci); + wait_event_interruptible(gsm->event, + dlci->state == DLCI_CLOSED); + } + /* Free up any link layer users */ + for (i = 0; i < NUM_DLCI; i++) + if (gsm->dlci[i]) + gsm_dlci_free(gsm->dlci[i]); + /* Now wipe the queues */ + for (txq = gsm->tx_head; txq != NULL; txq = gsm->tx_head) { + gsm->tx_head = txq->next; + kfree(txq); + } + gsm->tx_tail = NULL; +} +EXPORT_SYMBOL_GPL(gsm_cleanup_mux); + +/** + * gsm_activate_mux - generic GSM setup + * @gsm: our mux + * + * Set up the bits of the mux which are the same for all framing + * protocols. Add the mux to the mux table so it can be opened and + * finally kick off connecting to DLCI 0 on the modem. + */ + +int gsm_activate_mux(struct gsm_mux *gsm) +{ + struct gsm_dlci *dlci; + int i = 0; + + init_timer(&gsm->t2_timer); + gsm->t2_timer.function = gsm_control_retransmit; + gsm->t2_timer.data = (unsigned long)gsm; + init_waitqueue_head(&gsm->event); + spin_lock_init(&gsm->control_lock); + spin_lock_init(&gsm->tx_lock); + + if (gsm->encoding == 0) + gsm->receive = gsm0_receive; + else + gsm->receive = gsm1_receive; + gsm->error = gsm_error; + + spin_lock(&gsm_mux_lock); + for (i = 0; i < MAX_MUX; i++) { + if (gsm_mux[i] == NULL) { + gsm_mux[i] = gsm; + break; + } + } + spin_unlock(&gsm_mux_lock); + if (i == MAX_MUX) + return -EBUSY; + + dlci = gsm_dlci_alloc(gsm, 0); + if (dlci == NULL) + return -ENOMEM; + gsm->dead = 0; /* Tty opens are now permissible */ + return 0; +} +EXPORT_SYMBOL_GPL(gsm_activate_mux); + +/** + * gsm_free_mux - free up a mux + * @mux: mux to free + * + * Dispose of allocated resources for a dead mux. No refcounting + * at present so the mux must be truely dead. + */ +void gsm_free_mux(struct gsm_mux *gsm) +{ + kfree(gsm->txframe); + kfree(gsm->buf); + kfree(gsm); +} +EXPORT_SYMBOL_GPL(gsm_free_mux); + +/** + * gsm_alloc_mux - allocate a mux + * + * Creates a new mux ready for activation. + */ + +struct gsm_mux *gsm_alloc_mux(void) +{ + struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL); + if (gsm == NULL) + return NULL; + gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL); + if (gsm->buf == NULL) { + kfree(gsm); + return NULL; + } + gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL); + if (gsm->txframe == NULL) { + kfree(gsm->buf); + kfree(gsm); + return NULL; + } + spin_lock_init(&gsm->lock); + + gsm->t1 = T1; + gsm->t2 = T2; + gsm->n2 = N2; + gsm->ftype = UIH; + gsm->initiator = 0; + gsm->adaption = 1; + gsm->encoding = 1; + gsm->mru = 64; /* Default to encoding 1 so these should be 64 */ + gsm->mtu = 64; + gsm->dead = 1; /* Avoid early tty opens */ + + return gsm; +} +EXPORT_SYMBOL_GPL(gsm_alloc_mux); + + + + +/** + * gsmld_output - write to link + * @gsm: our mux + * @data: bytes to output + * @len: size + * + * Write a block of data from the GSM mux to the data channel. This + * will eventually be serialized from above but at the moment isn't. + */ + +static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len) +{ + if (tty_write_room(gsm->tty) < len) { + set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags); + return -ENOSPC; + } + if (debug & 4) { + printk("-->%d bytes out\n", len); + hex_packet(data, len); + } + gsm->tty->ops->write(gsm->tty, data, len); + return len; +} + +/** + * gsmld_attach_gsm - mode set up + * @tty: our tty structure + * @gsm: our mux + * + * Set up the MUX for basic mode and commence connecting to the + * modem. Currently called from the line discipline set up but + * will need moving to an ioctl path. + */ + +static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) +{ + int ret; + + gsm->tty = tty_kref_get(tty); + gsm->output = gsmld_output; + ret = gsm_activate_mux(gsm); + if (ret != 0) + tty_kref_put(gsm->tty); + return ret; +} + + +/** + * gsmld_detach_gsm - stop doing 0710 mux + * @tty: tty atttached to the mux + * @gsm: mux + * + * Shutdown and then clean up the resources used by the line discipline + */ + +static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) +{ + WARN_ON(tty != gsm->tty); + gsm_cleanup_mux(gsm); + tty_kref_put(gsm->tty); + gsm->tty = NULL; +} + +static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp, + char *fp, int count) +{ + struct gsm_mux *gsm = tty->disc_data; + const unsigned char *dp; + char *f; + int i; + char buf[64]; + char flags; + + if (debug & 4) { + printk("Inbytes %dd\n", count); + hex_packet(cp, count); + } + + for (i = count, dp = cp, f = fp; i; i--, dp++) { + flags = *f++; + switch (flags) { + case TTY_NORMAL: + gsm->receive(gsm, *dp); + break; + case TTY_OVERRUN: + case TTY_BREAK: + case TTY_PARITY: + case TTY_FRAME: + gsm->error(gsm, *dp, flags); + break; + default: + printk(KERN_ERR "%s: unknown flag %d\n", + tty_name(tty, buf), flags); + break; + } + } + /* FASYNC if needed ? */ + /* If clogged call tty_throttle(tty); */ +} + +/** + * gsmld_chars_in_buffer - report available bytes + * @tty: tty device + * + * Report the number of characters buffered to be delivered to user + * at this instant in time. + * + * Locking: gsm lock + */ + +static ssize_t gsmld_chars_in_buffer(struct tty_struct *tty) +{ + return 0; +} + +/** + * gsmld_flush_buffer - clean input queue + * @tty: terminal device + * + * Flush the input buffer. Called when the line discipline is + * being closed, when the tty layer wants the buffer flushed (eg + * at hangup). + */ + +static void gsmld_flush_buffer(struct tty_struct *tty) +{ +} + +/** + * gsmld_close - close the ldisc for this tty + * @tty: device + * + * Called from the terminal layer when this line discipline is + * being shut down, either because of a close or becsuse of a + * discipline change. The function will not be called while other + * ldisc methods are in progress. + */ + +static void gsmld_close(struct tty_struct *tty) +{ + struct gsm_mux *gsm = tty->disc_data; + + gsmld_detach_gsm(tty, gsm); + + gsmld_flush_buffer(tty); + /* Do other clean up here */ + gsm_free_mux(gsm); +} + +/** + * gsmld_open - open an ldisc + * @tty: terminal to open + * + * Called when this line discipline is being attached to the + * terminal device. Can sleep. Called serialized so that no + * other events will occur in parallel. No further open will occur + * until a close. + */ + +static int gsmld_open(struct tty_struct *tty) +{ + struct gsm_mux *gsm; + + if (tty->ops->write == NULL) + return -EINVAL; + + /* Attach our ldisc data */ + gsm = gsm_alloc_mux(); + if (gsm == NULL) + return -ENOMEM; + + tty->disc_data = gsm; + tty->receive_room = 65536; + + /* Attach the initial passive connection */ + gsm->encoding = 1; + return gsmld_attach_gsm(tty, gsm); +} + +/** + * gsmld_write_wakeup - asynchronous I/O notifier + * @tty: tty device + * + * Required for the ptys, serial driver etc. since processes + * that attach themselves to the master and rely on ASYNC + * IO must be woken up + */ + +static void gsmld_write_wakeup(struct tty_struct *tty) +{ + struct gsm_mux *gsm = tty->disc_data; + unsigned long flags; + + /* Queue poll */ + clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); + gsm_data_kick(gsm); + if (gsm->tx_bytes < TX_THRESH_LO) { + spin_lock_irqsave(&gsm->tx_lock, flags); + gsm_dlci_data_sweep(gsm); + spin_unlock_irqrestore(&gsm->tx_lock, flags); + } +} + +/** + * gsmld_read - read function for tty + * @tty: tty device + * @file: file object + * @buf: userspace buffer pointer + * @nr: size of I/O + * + * Perform reads for the line discipline. We are guaranteed that the + * line discipline will not be closed under us but we may get multiple + * parallel readers and must handle this ourselves. We may also get + * a hangup. Always called in user context, may sleep. + * + * This code must be sure never to sleep through a hangup. + */ + +static ssize_t gsmld_read(struct tty_struct *tty, struct file *file, + unsigned char __user *buf, size_t nr) +{ + return -EOPNOTSUPP; +} + +/** + * gsmld_write - write function for tty + * @tty: tty device + * @file: file object + * @buf: userspace buffer pointer + * @nr: size of I/O + * + * Called when the owner of the device wants to send a frame + * itself (or some other control data). The data is transferred + * as-is and must be properly framed and checksummed as appropriate + * by userspace. Frames are either sent whole or not at all as this + * avoids pain user side. + */ + +static ssize_t gsmld_write(struct tty_struct *tty, struct file *file, + const unsigned char *buf, size_t nr) +{ + int space = tty_write_room(tty); + if (space >= nr) + return tty->ops->write(tty, buf, nr); + set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); + return -ENOBUFS; +} + +/** + * gsmld_poll - poll method for N_GSM0710 + * @tty: terminal device + * @file: file accessing it + * @wait: poll table + * + * Called when the line discipline is asked to poll() for data or + * for special events. This code is not serialized with respect to + * other events save open/close. + * + * This code must be sure never to sleep through a hangup. + * Called without the kernel lock held - fine + */ + +static unsigned int gsmld_poll(struct tty_struct *tty, struct file *file, + poll_table *wait) +{ + unsigned int mask = 0; + struct gsm_mux *gsm = tty->disc_data; + + poll_wait(file, &tty->read_wait, wait); + poll_wait(file, &tty->write_wait, wait); + if (tty_hung_up_p(file)) + mask |= POLLHUP; + if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0) + mask |= POLLOUT | POLLWRNORM; + if (gsm->dead) + mask |= POLLHUP; + return mask; +} + +static int gsmld_config(struct tty_struct *tty, struct gsm_mux *gsm, + struct gsm_config *c) +{ + int need_close = 0; + int need_restart = 0; + + /* Stuff we don't support yet - UI or I frame transport, windowing */ + if ((c->adaption !=1 && c->adaption != 2) || c->k) + return -EOPNOTSUPP; + /* Check the MRU/MTU range looks sane */ + if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8) + return -EINVAL; + if (c->n2 < 3) + return -EINVAL; + if (c->encapsulation > 1) /* Basic, advanced, no I */ + return -EINVAL; + if (c->initiator > 1) + return -EINVAL; + if (c->i == 0 || c->i > 2) /* UIH and UI only */ + return -EINVAL; + /* + * See what is needed for reconfiguration + */ + + /* Timing fields */ + if (c->t1 != 0 && c->t1 != gsm->t1) + need_restart = 1; + if (c->t2 != 0 && c->t2 != gsm->t2) + need_restart = 1; + if (c->encapsulation != gsm->encoding) + need_restart = 1; + if (c->adaption != gsm->adaption) + need_restart = 1; + /* Requires care */ + if (c->initiator != gsm->initiator) + need_close = 1; + if (c->mru != gsm->mru) + need_restart = 1; + if (c->mtu != gsm->mtu) + need_restart = 1; + + /* + * Close down what is needed, restart and initiate the new + * configuration + */ + + if (need_close || need_restart) { + gsm_dlci_begin_close(gsm->dlci[0]); + /* This will timeout if the link is down due to N2 expiring */ + wait_event_interruptible(gsm->event, + gsm->dlci[0]->state == DLCI_CLOSED); + if (signal_pending(current)) + return -EINTR; + } + if (need_restart) + gsm_cleanup_mux(gsm); + + gsm->initiator = c->initiator; + gsm->mru = c->mru; + gsm->encoding = c->encapsulation; + gsm->adaption = c->adaption; + + if (c->i == 1) + gsm->ftype = UIH; + else if (c->i == 2) + gsm->ftype = UI; + + if (c->t1) + gsm->t1 = c->t1; + if (c->t2) + gsm->t2 = c->t2; + + /* FIXME: We need to separate activation/deactivation from adding + and removing from the mux array */ + if (need_restart) + gsm_activate_mux(gsm); + if (gsm->initiator && need_close) + gsm_dlci_begin_open(gsm->dlci[0]); + return 0; +} + +static int gsmld_ioctl(struct tty_struct *tty, struct file *file, + unsigned int cmd, unsigned long arg) +{ + struct gsm_config c; + struct gsm_mux *gsm = tty->disc_data; + + switch (cmd) { + case GSMIOC_GETCONF: + memset(&c, 0, sizeof(c)); + c.adaption = gsm->adaption; + c.encapsulation = gsm->encoding; + c.initiator = gsm->initiator; + c.t1 = gsm->t1; + c.t2 = gsm->t2; + c.t3 = 0; /* Not supported */ + c.n2 = gsm->n2; + if (gsm->ftype == UIH) + c.i = 1; + else + c.i = 2; + printk("Ftype %d i %d\n", gsm->ftype, c.i); + c.mru = gsm->mru; + c.mtu = gsm->mtu; + c.k = 0; + if (copy_to_user((void *)arg, &c, sizeof(c))) + return -EFAULT; + return 0; + case GSMIOC_SETCONF: + if (copy_from_user(&c, (void *)arg, sizeof(c))) + return -EFAULT; + return gsmld_config(tty, gsm, &c); + default: + return n_tty_ioctl_helper(tty, file, cmd, arg); + } +} + + +/* Line discipline for real tty */ +struct tty_ldisc_ops tty_ldisc_packet = { + .owner = THIS_MODULE, + .magic = TTY_LDISC_MAGIC, + .name = "n_gsm", + .open = gsmld_open, + .close = gsmld_close, + .flush_buffer = gsmld_flush_buffer, + .chars_in_buffer = gsmld_chars_in_buffer, + .read = gsmld_read, + .write = gsmld_write, + .ioctl = gsmld_ioctl, + .poll = gsmld_poll, + .receive_buf = gsmld_receive_buf, + .write_wakeup = gsmld_write_wakeup +}; + +/* + * Virtual tty side + */ + +#define TX_SIZE 512 + +static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk) +{ + u8 modembits[5]; + struct gsm_control *ctrl; + int len = 2; + + if (brk) + len++; + + modembits[0] = len << 1 | EA; /* Data bytes */ + modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */ + modembits[2] = gsm_encode_modem(dlci) << 1 | EA; + if (brk) + modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */ + ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1); + if (ctrl == NULL) + return -ENOMEM; + return gsm_control_wait(dlci->gsm, ctrl); +} + +static int gsm_carrier_raised(struct tty_port *port) +{ + struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); + /* Not yet open so no carrier info */ + if (dlci->state != DLCI_OPEN) + return 0; + if (debug & 2) + return 1; + return dlci->modem_rx & TIOCM_CD; +} + +static void gsm_dtr_rts(struct tty_port *port, int onoff) +{ + struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); + unsigned int modem_tx = dlci->modem_tx; + if (onoff) + modem_tx |= TIOCM_DTR | TIOCM_RTS; + else + modem_tx &= ~(TIOCM_DTR | TIOCM_RTS); + if (modem_tx != dlci->modem_tx) { + dlci->modem_tx = modem_tx; + gsmtty_modem_update(dlci, 0); + } +} + +static const struct tty_port_operations gsm_port_ops = { + .carrier_raised = gsm_carrier_raised, + .dtr_rts = gsm_dtr_rts, +}; + + +static int gsmtty_open(struct tty_struct *tty, struct file *filp) +{ + struct gsm_mux *gsm; + struct gsm_dlci *dlci; + struct tty_port *port; + unsigned int line = tty->index; + unsigned int mux = line >> 6; + + line = line & 0x3F; + + if (mux >= MAX_MUX) + return -ENXIO; + /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */ + if (gsm_mux[mux] == NULL) + return -EUNATCH; + if (line == 0 || line > 61) /* 62/63 reserved */ + return -ECHRNG; + gsm = gsm_mux[mux]; + if (gsm->dead) + return -EL2HLT; + dlci = gsm->dlci[line]; + if (dlci == NULL) + dlci = gsm_dlci_alloc(gsm, line); + if (dlci == NULL) + return -ENOMEM; + port = &dlci->port; + port->count++; + tty->driver_data = dlci; + tty_port_tty_set(port, tty); + + dlci->modem_rx = 0; + /* We could in theory open and close before we wait - eg if we get + a DM straight back. This is ok as that will have caused a hangup */ + set_bit(ASYNCB_INITIALIZED, &port->flags); + /* Start sending off SABM messages */ + gsm_dlci_begin_open(dlci); + /* And wait for virtual carrier */ + return tty_port_block_til_ready(port, tty, filp); +} + +static void gsmtty_close(struct tty_struct *tty, struct file *filp) +{ + struct gsm_dlci *dlci = tty->driver_data; + if (dlci == NULL) + return; + if (tty_port_close_start(&dlci->port, tty, filp) == 0) + return; + gsm_dlci_begin_close(dlci); + tty_port_close_end(&dlci->port, tty); + tty_port_tty_set(&dlci->port, NULL); +} + +static void gsmtty_hangup(struct tty_struct *tty) +{ + struct gsm_dlci *dlci = tty->driver_data; + tty_port_hangup(&dlci->port); + gsm_dlci_begin_close(dlci); +} + +static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf, + int len) +{ + struct gsm_dlci *dlci = tty->driver_data; + /* Stuff the bytes into the fifo queue */ + int sent = kfifo_in_locked(dlci->fifo, buf, len, &dlci->lock); + /* Need to kick the channel */ + gsm_dlci_data_kick(dlci); + return sent; +} + +static int gsmtty_write_room(struct tty_struct *tty) +{ + struct gsm_dlci *dlci = tty->driver_data; + return TX_SIZE - kfifo_len(dlci->fifo); +} + +static int gsmtty_chars_in_buffer(struct tty_struct *tty) +{ + struct gsm_dlci *dlci = tty->driver_data; + return kfifo_len(dlci->fifo); +} + +static void gsmtty_flush_buffer(struct tty_struct *tty) +{ + struct gsm_dlci *dlci = tty->driver_data; + /* Caution needed: If we implement reliable transport classes + then the data being transmitted can't simply be junked once + it has first hit the stack. Until then we can just blow it + away */ + kfifo_reset(dlci->fifo); + /* Need to unhook this DLCI from the transmit queue logic */ +} + +static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout) +{ + /* The FIFO handles the queue so the kernel will do the right + thing waiting on chars_in_buffer before calling us. No work + to do here */ +} + +static int gsmtty_tiocmget(struct tty_struct *tty, struct file *filp) +{ + struct gsm_dlci *dlci = tty->driver_data; + return dlci->modem_rx; +} + +static int gsmtty_tiocmset(struct tty_struct *tty, struct file *filp, + unsigned int set, unsigned int clear) +{ + struct gsm_dlci *dlci = tty->driver_data; + unsigned int modem_tx = dlci->modem_tx; + + modem_tx &= clear; + modem_tx |= set; + + if (modem_tx != dlci->modem_tx) { + dlci->modem_tx = modem_tx; + return gsmtty_modem_update(dlci, 0); + } + return 0; +} + + +static int gsmtty_ioctl(struct tty_struct *tty, struct file *filp, + unsigned int cmd, unsigned long arg) +{ + return -ENOIOCTLCMD; +} + +static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old) +{ + /* For the moment its fixed. In actual fact the speed information + for the virtual channel can be propogated in both directions by + the RPN control message. This however rapidly gets nasty as we + then have to remap modem signals each way according to whether + our virtual cable is null modem etc .. */ + tty_termios_copy_hw(tty->termios, old); +} + +static void gsmtty_throttle(struct tty_struct *tty) +{ + struct gsm_dlci *dlci = tty->driver_data; + if (tty->termios->c_cflag & CRTSCTS) + dlci->modem_tx &= ~TIOCM_DTR; + dlci->throttled = 1; + /* Send an MSC with DTR cleared */ + gsmtty_modem_update(dlci, 0); +} + +static void gsmtty_unthrottle(struct tty_struct *tty) +{ + struct gsm_dlci *dlci = tty->driver_data; + if (tty->termios->c_cflag & CRTSCTS) + dlci->modem_tx |= TIOCM_DTR; + dlci->throttled = 0; + /* Send an MSC with DTR set */ + gsmtty_modem_update(dlci, 0); +} + +static int gsmtty_break_ctl(struct tty_struct *tty, int state) +{ + struct gsm_dlci *dlci = tty->driver_data; + int encode = 0; /* Off */ + + if (state == -1) /* "On indefinitely" - we can't encode this + properly */ + encode = 0x0F; + else if (state > 0) { + encode = state / 200; /* mS to encoding */ + if (encode > 0x0F) + encode = 0x0F; /* Best effort */ + } + return gsmtty_modem_update(dlci, encode); +} + +static struct tty_driver *gsm_tty_driver; + +/* Virtual ttys for the demux */ +static const struct tty_operations gsmtty_ops = { + .open = gsmtty_open, + .close = gsmtty_close, + .write = gsmtty_write, + .write_room = gsmtty_write_room, + .chars_in_buffer = gsmtty_chars_in_buffer, + .flush_buffer = gsmtty_flush_buffer, + .ioctl = gsmtty_ioctl, + .throttle = gsmtty_throttle, + .unthrottle = gsmtty_unthrottle, + .set_termios = gsmtty_set_termios, + .hangup = gsmtty_hangup, + .wait_until_sent = gsmtty_wait_until_sent, + .tiocmget = gsmtty_tiocmget, + .tiocmset = gsmtty_tiocmset, + .break_ctl = gsmtty_break_ctl, +}; + + + +static int __init gsm_init(void) +{ + /* Fill in our line protocol discipline, and register it */ + int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet); + if (status != 0) { + printk(KERN_ERR "n_gsm: can't register line discipline (err = %d)\n", status); + return status; + } + + gsm_tty_driver = alloc_tty_driver(256); + if (!gsm_tty_driver) { + tty_unregister_ldisc(N_GSM0710); + printk(KERN_ERR "gsm_init: tty allocation failed.\n"); + return -EINVAL; + } + gsm_tty_driver->owner = THIS_MODULE; + gsm_tty_driver->driver_name = "gsmtty"; + gsm_tty_driver->name = "gsmtty"; + gsm_tty_driver->major = 0; /* Dynamic */ + gsm_tty_driver->minor_start = 0; + gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL; + gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL; + gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV + | TTY_DRIVER_HARDWARE_BREAK; + gsm_tty_driver->init_termios = tty_std_termios; + /* Fixme */ + gsm_tty_driver->init_termios.c_lflag &= ~ECHO; + tty_set_operations(gsm_tty_driver, &gsmtty_ops); + + spin_lock_init(&gsm_mux_lock); + + if (tty_register_driver(gsm_tty_driver)) { + put_tty_driver(gsm_tty_driver); + tty_unregister_ldisc(N_GSM0710); + printk(KERN_ERR "gsm_init: tty registration failed.\n"); + return -EBUSY; + } + printk(KERN_INFO "gsm_init: loaded as %d,%d.\n", gsm_tty_driver->major, gsm_tty_driver->minor_start); + return 0; +} + +static void __exit gsm_exit(void) +{ + int status = tty_unregister_ldisc(N_GSM0710); + if (status != 0) + printk(KERN_ERR "n_gsm: can't unregister line discipline (err = %d)\n", status); + tty_unregister_driver(gsm_tty_driver); + put_tty_driver(gsm_tty_driver); + printk(KERN_INFO "gsm_init: unloaded.\n"); +} + +module_init(gsm_init); +module_exit(gsm_exit); + + +MODULE_LICENSE("GPL"); +MODULE_ALIAS_LDISC(N_GSM0710); |
