| /* |
| * 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) |
| return; |
| /* 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); |