/* ######################################################################## tty0tty - linux null modem emulator (module) for kernel > 3.0 ######################################################################## Copyright (c) : 2012 Luis Claudio Gambôa Lopes Based in Tiny TTY driver - Copyright (C) 2002-2004 Greg Kroah-Hartman (greg@kroah.com) This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. 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. For e-mail suggestions : lcgamboa@yahoo.com ######################################################################## */ #include #include #include #include #include #include #include #include #include #include #include #include #define DRIVER_VERSION "v1.1" #define DRIVER_AUTHOR "Luis Claudio Gamboa Lopes " #define DRIVER_DESC "tty0tty null modem driver" /* Module information */ MODULE_AUTHOR( DRIVER_AUTHOR ); MODULE_DESCRIPTION( DRIVER_DESC ); MODULE_LICENSE("GPL"); #define TINY_TTY_MAJOR 240 /* experimental range */ #define TINY_TTY_MINORS 8 /* device number, always even*/ /* fake UART values */ //out #define MCR_DTR 0x01 #define MCR_RTS 0x02 #define MCR_LOOP 0x04 //in #define MSR_CTS 0x10 #define MSR_CD 0x20 #define MSR_DSR 0x40 #define MSR_RI 0x80 struct tty0tty_serial { struct tty_struct *tty; /* pointer to the tty for this device */ int open_count; /* number of times this port has been opened */ struct semaphore sem; /* locks this structure */ /* for tiocmget and tiocmset functions */ int msr; /* MSR shadow */ int mcr; /* MCR shadow */ /* for ioctl fun */ struct serial_struct serial; wait_queue_head_t wait; struct async_icount icount; }; static struct tty0tty_serial *tty0tty_table[TINY_TTY_MINORS]; /* initially all NULL */ static int tty0tty_open(struct tty_struct *tty, struct file *file) { struct tty0tty_serial *tty0tty; int index; int msr=0; int mcr=0; #ifdef SCULL_DEBUG printk(KERN_DEBUG "%s - \n", __FUNCTION__); #endif /* initialize the pointer in case something fails */ tty->driver_data = NULL; /* get the serial object associated with this tty pointer */ index = tty->index; tty0tty = tty0tty_table[index]; if (tty0tty == NULL) { /* first time accessing this device, let's create it */ tty0tty = kmalloc(sizeof(*tty0tty), GFP_KERNEL); if (!tty0tty) return -ENOMEM; sema_init(&tty0tty->sem,1); tty0tty->open_count = 0; tty0tty_table[index] = tty0tty; init_waitqueue_head(&tty0tty->wait); } if( (index % 2) == 0) { if(tty0tty_table[index+1] != NULL) if (tty0tty_table[index+1]->open_count > 0) mcr=tty0tty_table[index+1]->mcr; } else { if(tty0tty_table[index-1] != NULL) if (tty0tty_table[index-1]->open_count > 0) mcr=tty0tty_table[index-1]->mcr; } //null modem connection if( (mcr & MCR_RTS) == MCR_RTS ) { msr |= MSR_CTS; } if( (mcr & MCR_DTR) == MCR_DTR ) { msr |= MSR_DSR; msr |= MSR_CD; } tty0tty->msr = msr; tty0tty->mcr = 0; down(&tty0tty->sem); /* save our structure within the tty structure */ tty->driver_data = tty0tty; tty0tty->tty = tty; ++tty0tty->open_count; up(&tty0tty->sem); return 0; } static void do_close(struct tty0tty_serial *tty0tty) { unsigned int msr=0; #ifdef SCULL_DEBUG printk(KERN_DEBUG "%s - \n", __FUNCTION__); #endif if( (tty0tty->tty->index % 2) == 0) { if(tty0tty_table[tty0tty->tty->index+1] != NULL) if (tty0tty_table[tty0tty->tty->index+1]->open_count > 0) tty0tty_table[tty0tty->tty->index+1]->msr=msr; } else { if(tty0tty_table[tty0tty->tty->index-1] != NULL) if (tty0tty_table[tty0tty->tty->index-1]->open_count > 0) tty0tty_table[tty0tty->tty->index-1]->msr=msr; } down(&tty0tty->sem); if (!tty0tty->open_count) { /* port was never opened */ goto exit; } --tty0tty->open_count; exit: up(&tty0tty->sem); return; } static void tty0tty_close(struct tty_struct *tty, struct file *file) { struct tty0tty_serial *tty0tty = tty->driver_data; #ifdef SCULL_DEBUG printk(KERN_DEBUG "%s - \n", __FUNCTION__); #endif if (tty0tty) do_close(tty0tty); } static int tty0tty_write(struct tty_struct *tty, const unsigned char *buffer, int count) { struct tty0tty_serial *tty0tty = tty->driver_data; int retval = -EINVAL; struct tty_struct *ttyx = NULL; if (!tty0tty) return -ENODEV; down(&tty0tty->sem); if (!tty0tty->open_count) /* port was not opened */ goto exit; if( (tty0tty->tty->index % 2) == 0) { if(tty0tty_table[tty0tty->tty->index+1] != NULL) if (tty0tty_table[tty0tty->tty->index+1]->open_count > 0) ttyx=tty0tty_table[tty0tty->tty->index+1]->tty; } else { if(tty0tty_table[tty0tty->tty->index-1] != NULL) if (tty0tty_table[tty0tty->tty->index-1]->open_count > 0) ttyx=tty0tty_table[tty0tty->tty->index-1]->tty; } // tty->low_latency=1; if(ttyx != NULL) { tty_insert_flip_string(ttyx, buffer, count); tty_flip_buffer_push(ttyx); retval=count; } exit: up(&tty0tty->sem); return retval; } static int tty0tty_write_room(struct tty_struct *tty) { struct tty0tty_serial *tty0tty = tty->driver_data; int room = -EINVAL; if (!tty0tty) return -ENODEV; down(&tty0tty->sem); if (!tty0tty->open_count) { /* port was not opened */ goto exit; } /* calculate how much room is left in the device */ room = 255; exit: up(&tty0tty->sem); return room; } #define RELEVANT_IFLAG(iflag) ((iflag) & (IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK)) static void tty0tty_set_termios(struct tty_struct *tty, struct ktermios *old_termios) { unsigned int cflag; #ifdef SCULL_DEBUG printk(KERN_DEBUG "%s - \n", __FUNCTION__); #endif cflag = tty->termios->c_cflag; /* check that they really want us to change something */ if (old_termios) { if ((cflag == old_termios->c_cflag) && (RELEVANT_IFLAG(tty->termios->c_iflag) == RELEVANT_IFLAG(old_termios->c_iflag))) { #ifdef SCULL_DEBUG printk(KERN_DEBUG " - nothing to change...\n"); #endif return; } } #ifdef SCULL_DEBUG /* get the byte size */ switch (cflag & CSIZE) { case CS5: printk(KERN_DEBUG " - data bits = 5\n"); break; case CS6: printk(KERN_DEBUG " - data bits = 6\n"); break; case CS7: printk(KERN_DEBUG " - data bits = 7\n"); break; default: case CS8: printk(KERN_DEBUG " - data bits = 8\n"); break; } /* determine the parity */ if (cflag & PARENB) if (cflag & PARODD) printk(KERN_DEBUG " - parity = odd\n"); else printk(KERN_DEBUG " - parity = even\n"); else printk(KERN_DEBUG " - parity = none\n"); /* figure out the stop bits requested */ if (cflag & CSTOPB) printk(KERN_DEBUG " - stop bits = 2\n"); else printk(KERN_DEBUG " - stop bits = 1\n"); /* figure out the hardware flow control settings */ if (cflag & CRTSCTS) printk(KERN_DEBUG " - RTS/CTS is enabled\n"); else printk(KERN_DEBUG " - RTS/CTS is disabled\n"); /* determine software flow control */ /* if we are implementing XON/XOFF, set the start and * stop character in the device */ if (I_IXOFF(tty) || I_IXON(tty)) { unsigned char stop_char = STOP_CHAR(tty); unsigned char start_char = START_CHAR(tty); /* if we are implementing INBOUND XON/XOFF */ if (I_IXOFF(tty)) printk(KERN_DEBUG " - INBOUND XON/XOFF is enabled, " "XON = %2x, XOFF = %2x\n", start_char, stop_char); else printk(KERN_DEBUG" - INBOUND XON/XOFF is disabled\n"); /* if we are implementing OUTBOUND XON/XOFF */ if (I_IXON(tty)) printk(KERN_DEBUG" - OUTBOUND XON/XOFF is enabled, " "XON = %2x, XOFF = %2x\n", start_char, stop_char); else printk(KERN_DEBUG" - OUTBOUND XON/XOFF is disabled\n"); } /* get the baud rate wanted */ printk(KERN_DEBUG " - baud rate = %d\n", tty_get_baud_rate(tty)); #endif } //static int tty0tty_tiocmget(struct tty_struct *tty, struct file *file) static int tty0tty_tiocmget(struct tty_struct *tty) { struct tty0tty_serial *tty0tty = tty->driver_data; unsigned int result = 0; unsigned int msr = tty0tty->msr; unsigned int mcr = tty0tty->mcr; #ifdef SCULL_DEBUG printk(KERN_DEBUG "%s - \n", __FUNCTION__); #endif result = ((mcr & MCR_DTR) ? TIOCM_DTR : 0) | /* DTR is set */ ((mcr & MCR_RTS) ? TIOCM_RTS : 0) | /* RTS is set */ ((mcr & MCR_LOOP) ? TIOCM_LOOP : 0) | /* LOOP is set */ ((msr & MSR_CTS) ? TIOCM_CTS : 0) | /* CTS is set */ ((msr & MSR_CD) ? TIOCM_CAR : 0) | /* Carrier detect is set*/ ((msr & MSR_RI) ? TIOCM_RI : 0) | /* Ring Indicator is set */ ((msr & MSR_DSR) ? TIOCM_DSR : 0); /* DSR is set */ return result; } //static int tty0tty_tiocmset(struct tty_struct *tty, struct file *file, static int tty0tty_tiocmset(struct tty_struct *tty, unsigned int set, unsigned int clear) { struct tty0tty_serial *tty0tty = tty->driver_data; unsigned int mcr = tty0tty->mcr; unsigned int msr=0; #ifdef SCULL_DEBUG printk(KERN_DEBUG "%s - \n", __FUNCTION__); #endif if( (tty0tty->tty->index % 2) == 0) { if(tty0tty_table[tty0tty->tty->index+1] != NULL) if (tty0tty_table[tty0tty->tty->index+1]->open_count > 0) msr=tty0tty_table[tty0tty->tty->index+1]->msr; } else { if(tty0tty_table[tty0tty->tty->index-1] != NULL) if (tty0tty_table[tty0tty->tty->index-1]->open_count > 0) msr=tty0tty_table[tty0tty->tty->index-1]->msr; } //null modem connection if (set & TIOCM_RTS) { mcr |= MCR_RTS; msr |= MSR_CTS; } if (set & TIOCM_DTR) { mcr |= MCR_DTR; msr |= MSR_DSR; msr |= MSR_CD; } if (clear & TIOCM_RTS) { mcr &= ~MCR_RTS; msr &= ~MSR_CTS; } if (clear & TIOCM_DTR) { mcr &= ~MCR_DTR; msr &= ~MSR_DSR; msr &= ~MSR_CD; } /* set the new MCR value in the device */ tty0tty->mcr = mcr; if( (tty0tty->tty->index % 2) == 0) { if(tty0tty_table[tty0tty->tty->index+1] != NULL) if (tty0tty_table[tty0tty->tty->index+1]->open_count > 0) tty0tty_table[tty0tty->tty->index+1]->msr=msr; } else { if(tty0tty_table[tty0tty->tty->index-1] != NULL) if (tty0tty_table[tty0tty->tty->index-1]->open_count > 0) tty0tty_table[tty0tty->tty->index-1]->msr=msr; } return 0; } static int tty0tty_ioctl_tiocgserial(struct tty_struct *tty, unsigned int cmd, unsigned long arg) { struct tty0tty_serial *tty0tty = tty->driver_data; #ifdef SCULL_DEBUG printk(KERN_DEBUG "%s - \n", __FUNCTION__); #endif if (cmd == TIOCGSERIAL) { struct serial_struct tmp; if (!arg) return -EFAULT; memset(&tmp, 0, sizeof(tmp)); tmp.type = tty0tty->serial.type; tmp.line = tty0tty->serial.line; tmp.port = tty0tty->serial.port; tmp.irq = tty0tty->serial.irq; tmp.flags = ASYNC_SKIP_TEST | ASYNC_AUTO_IRQ; tmp.xmit_fifo_size = tty0tty->serial.xmit_fifo_size; tmp.baud_base = tty0tty->serial.baud_base; tmp.close_delay = 5*HZ; tmp.closing_wait = 30*HZ; tmp.custom_divisor = tty0tty->serial.custom_divisor; tmp.hub6 = tty0tty->serial.hub6; tmp.io_type = tty0tty->serial.io_type; if (copy_to_user((void __user *)arg, &tmp, sizeof(struct serial_struct))) return -EFAULT; return 0; } return -ENOIOCTLCMD; } static int tty0tty_ioctl_tiocmiwait(struct tty_struct *tty, unsigned int cmd, unsigned long arg) { struct tty0tty_serial *tty0tty = tty->driver_data; #ifdef SCULL_DEBUG printk(KERN_DEBUG "%s -\n", __FUNCTION__); #endif if (cmd == TIOCMIWAIT) { DECLARE_WAITQUEUE(wait, current); struct async_icount cnow; struct async_icount cprev; cprev = tty0tty->icount; while (1) { add_wait_queue(&tty0tty->wait, &wait); set_current_state(TASK_INTERRUPTIBLE); schedule(); remove_wait_queue(&tty0tty->wait, &wait); /* see if a signal woke us up */ if (signal_pending(current)) return -ERESTARTSYS; cnow = tty0tty->icount; if (cnow.rng == cprev.rng && cnow.dsr == cprev.dsr && cnow.dcd == cprev.dcd && cnow.cts == cprev.cts) return -EIO; /* no change => error */ if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) || ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) || ((arg & TIOCM_CD) && (cnow.dcd != cprev.dcd)) || ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts)) ) { return 0; } cprev = cnow; } } return -ENOIOCTLCMD; } static int tty0tty_ioctl_tiocgicount(struct tty_struct *tty, unsigned int cmd, unsigned long arg) { struct tty0tty_serial *tty0tty = tty->driver_data; #ifdef SCULL_DEBUG printk(KERN_DEBUG "%s - \n", __FUNCTION__); #endif if (cmd == TIOCGICOUNT) { struct async_icount cnow = tty0tty->icount; struct serial_icounter_struct icount; icount.cts = cnow.cts; icount.dsr = cnow.dsr; icount.rng = cnow.rng; icount.dcd = cnow.dcd; icount.rx = cnow.rx; icount.tx = cnow.tx; icount.frame = cnow.frame; icount.overrun = cnow.overrun; icount.parity = cnow.parity; icount.brk = cnow.brk; icount.buf_overrun = cnow.buf_overrun; if (copy_to_user((void __user *)arg, &icount, sizeof(icount))) return -EFAULT; return 0; } return -ENOIOCTLCMD; } static int tty0tty_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg) { #ifdef SCULL_DEBUG printk(KERN_DEBUG "%s - %04X \n", __FUNCTION__,cmd); #endif switch (cmd) { case TIOCGSERIAL: return tty0tty_ioctl_tiocgserial(tty, cmd, arg); case TIOCMIWAIT: return tty0tty_ioctl_tiocmiwait(tty, cmd, arg); case TIOCGICOUNT: return tty0tty_ioctl_tiocgicount(tty, cmd, arg); case TCGETS: return tty0tty_tiocmget(tty); case TCSETS: return tty0tty_tiocmset(tty, cmd, arg); } return -ENOIOCTLCMD; } static struct tty_operations serial_ops = { .open = tty0tty_open, .close = tty0tty_close, .write = tty0tty_write, .write_room = tty0tty_write_room, .set_termios = tty0tty_set_termios, .tiocmget = tty0tty_tiocmget, .tiocmset = tty0tty_tiocmset, .ioctl = tty0tty_ioctl, }; static struct tty_driver *tty0tty_tty_driver; static int __init tty0tty_init(void) { int retval; #ifdef SCULL_DEBUG printk(KERN_DEBUG "%s - \n", __FUNCTION__); #endif /* allocate the tty driver */ tty0tty_tty_driver = alloc_tty_driver(TINY_TTY_MINORS); if (!tty0tty_tty_driver) return -ENOMEM; /* initialize the tty driver */ tty0tty_tty_driver->owner = THIS_MODULE; tty0tty_tty_driver->driver_name = "tty0tty"; tty0tty_tty_driver->name = "tnt"; /* no more devfs subsystem */ tty0tty_tty_driver->major = TINY_TTY_MAJOR; tty0tty_tty_driver->type = TTY_DRIVER_TYPE_SERIAL; tty0tty_tty_driver->subtype = SERIAL_TYPE_NORMAL; tty0tty_tty_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW ; /* no more devfs subsystem */ tty0tty_tty_driver->init_termios = tty_std_termios; tty0tty_tty_driver->init_termios.c_iflag = 0; tty0tty_tty_driver->init_termios.c_oflag = 0; tty0tty_tty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; tty0tty_tty_driver->init_termios.c_lflag = 0; tty0tty_tty_driver->init_termios.c_ispeed = 38400; tty0tty_tty_driver->init_termios.c_ospeed = 38400; tty_set_operations(tty0tty_tty_driver, &serial_ops); /* register the tty driver */ retval = tty_register_driver(tty0tty_tty_driver); if (retval) { printk(KERN_ERR "failed to register tty0tty tty driver"); put_tty_driver(tty0tty_tty_driver); return retval; } printk(KERN_INFO DRIVER_DESC " " DRIVER_VERSION "\n"); return retval; } static void __exit tty0tty_exit(void) { struct tty0tty_serial *tty0tty; int i; #ifdef SCULL_DEBUG printk(KERN_DEBUG "%s - \n", __FUNCTION__); #endif for (i = 0; i < TINY_TTY_MINORS; ++i) tty_unregister_device(tty0tty_tty_driver, i); tty_unregister_driver(tty0tty_tty_driver); /* shut down all of the timers and free the memory */ for (i = 0; i < TINY_TTY_MINORS; ++i) { tty0tty = tty0tty_table[i]; if (tty0tty) { /* close the port */ while (tty0tty->open_count) do_close(tty0tty); /* shut down our timer and free the memory */ kfree(tty0tty); tty0tty_table[i] = NULL; } } } module_init(tty0tty_init); module_exit(tty0tty_exit);