ctctty.c

内核linux2.4.20,可跟rtlinux3.2打补丁 组成实时linux系统,编译内核

static int
ctc_tty_startup(ctc_tty_info * info)
{
	if (info->flags & CTC_ASYNC_INITIALIZED)
		return 0;
#ifdef CTC_DEBUG_MODEM_OPEN
	printk(KERN_DEBUG "starting up %s%d ...\n", CTC_TTY_NAME, info->line);
#endif
	/*
	 * Now, initialize the UART
	 */
	info->mcr = UART_MCR_DTR | UART_MCR_RTS | UART_MCR_OUT2;
	if (info->tty)
		clear_bit(TTY_IO_ERROR, &info->tty->flags);
	/*
	 * and set the speed of the serial port
	 */
	ctc_tty_change_speed(info);

	info->flags |= CTC_ASYNC_INITIALIZED;
	if (!(info->flags & CTC_ASYNC_NETDEV_OPEN))
		info->netdev->open(info->netdev);
	info->flags |= CTC_ASYNC_NETDEV_OPEN;
	return 0;
}

static void
ctc_tty_stopdev(unsigned long data)
{
	ctc_tty_info *info = (ctc_tty_info *)data;

	if ((!info) || (!info->netdev) ||
	    (info->flags & CTC_ASYNC_INITIALIZED))
		return;
	info->netdev->stop(info->netdev);
	info->flags &= ~CTC_ASYNC_NETDEV_OPEN;
}

/*
 * This routine will shutdown a serial port; interrupts are disabled, and
 * DTR is dropped if the hangup on close termio flag is on.
 */
static void
ctc_tty_shutdown(ctc_tty_info * info)
{
	if (!(info->flags & CTC_ASYNC_INITIALIZED))
		return;
#ifdef CTC_DEBUG_MODEM_OPEN
	printk(KERN_DEBUG "Shutting down %s%d ....\n", CTC_TTY_NAME, info->line);
#endif
	info->msr &= ~UART_MSR_RI;
	if (!info->tty || (info->tty->termios->c_cflag & HUPCL))
		info->mcr &= ~(UART_MCR_DTR | UART_MCR_RTS);
	if (info->tty)
		set_bit(TTY_IO_ERROR, &info->tty->flags);
	mod_timer(&info->stoptimer, jiffies + (10 * HZ));
	skb_queue_purge(&info->tx_queue);
	skb_queue_purge(&info->rx_queue);
	info->flags &= ~CTC_ASYNC_INITIALIZED;
}

/* ctc_tty_write() is the main send-routine. It is called from the upper
 * levels within the kernel to perform sending data. Depending on the
 * online-flag it either directs output to the at-command-interpreter or
 * to the lower level. Additional tasks done here:
 *  - If online, check for escape-sequence (+++)
 *  - If sending audio-data, call ctc_tty_DLEdown() to parse DLE-codes.
 *  - If receiving audio-data, call ctc_tty_end_vrx() to abort if needed.
 *  - If dialing, abort dial.
 */
static int
ctc_tty_write(struct tty_struct *tty, int from_user, const u_char * buf, int count)
{
	int c;
	int total = 0;
	ctc_tty_info *info = (ctc_tty_info *) tty->driver_data;

	if (ctc_tty_shuttingdown)
		return 0;
	if (ctc_tty_paranoia_check(info, tty->device, "ctc_tty_write"))
		return 0;
	if (!tty)
		return 0;
	if (!info->netdev)
		return -ENODEV;
	if (from_user)
		down(&info->write_sem);
	while (1) {
		struct sk_buff *skb;
		int skb_res;

		c = (count < CTC_TTY_XMIT_SIZE) ? count : CTC_TTY_XMIT_SIZE;
		if (c <= 0)
			break;
		
		skb_res = info->netdev->hard_header_len + sizeof(info->mcr) +
			+ sizeof(__u32);
		skb = dev_alloc_skb(skb_res + c);
		if (!skb) {
			printk(KERN_WARNING
			       "ctc_tty: Out of memory in %s%d write\n",
			       CTC_TTY_NAME, info->line);
			break;
		}
		skb_reserve(skb, skb_res);
		if (from_user)
			copy_from_user(skb_put(skb, c), buf, c);
		else
			memcpy(skb_put(skb, c), buf, c);
		skb_queue_tail(&info->tx_queue, skb);
		buf += c;
		total += c;
		count -= c;
	}
	if (skb_queue_len(&info->tx_queue)) {
		info->lsr &= ~UART_LSR_TEMT;
		queue_task(&info->tq, &tq_immediate);
		mark_bh(IMMEDIATE_BH);
	}
	if (from_user)
		up(&info->write_sem);
	return total;
}

static int
ctc_tty_write_room(struct tty_struct *tty)
{
	ctc_tty_info *info = (ctc_tty_info *) tty->driver_data;

	if (ctc_tty_paranoia_check(info, tty->device, "ctc_tty_write_room"))
		return 0;
	return CTC_TTY_XMIT_SIZE;
}

static int
ctc_tty_chars_in_buffer(struct tty_struct *tty)
{
	ctc_tty_info *info = (ctc_tty_info *) tty->driver_data;

	if (ctc_tty_paranoia_check(info, tty->device, "ctc_tty_chars_in_buffer"))
		return 0;
	return 0;
}

static void
ctc_tty_flush_buffer(struct tty_struct *tty)
{
	ctc_tty_info *info;
	unsigned long flags;

	save_flags(flags);
	cli();
	if (!tty) {
		restore_flags(flags);
		return;
	}
	info = (ctc_tty_info *) tty->driver_data;
	if (ctc_tty_paranoia_check(info, tty->device, "ctc_tty_flush_buffer")) {
		restore_flags(flags);
		return;
	}
	skb_queue_purge(&info->tx_queue);
	info->lsr |= UART_LSR_TEMT;
	restore_flags(flags);
	wake_up_interruptible(&tty->write_wait);
	if ((tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) &&
	    tty->ldisc.write_wakeup)
		(tty->ldisc.write_wakeup) (tty);
}

static void
ctc_tty_flush_chars(struct tty_struct *tty)
{
	ctc_tty_info *info = (ctc_tty_info *) tty->driver_data;

	if (ctc_tty_shuttingdown)
		return;
	if (ctc_tty_paranoia_check(info, tty->device, "ctc_tty_flush_chars"))
		return;
	if (tty->stopped || tty->hw_stopped || (!skb_queue_len(&info->tx_queue)))
		return;
	queue_task(&info->tq, &tq_immediate);
	mark_bh(IMMEDIATE_BH);
}

/*
 * ------------------------------------------------------------
 * ctc_tty_throttle()
 *
 * This routine is called by the upper-layer tty layer to signal that
 * incoming characters should be throttled.
 * ------------------------------------------------------------
 */
static void
ctc_tty_throttle(struct tty_struct *tty)
{
	ctc_tty_info *info = (ctc_tty_info *) tty->driver_data;

	if (ctc_tty_paranoia_check(info, tty->device, "ctc_tty_throttle"))
		return;
	info->mcr &= ~UART_MCR_RTS;
	if (I_IXOFF(tty))
		ctc_tty_inject(info, STOP_CHAR(tty));
	ctc_tty_transmit_status(info);
}

static void
ctc_tty_unthrottle(struct tty_struct *tty)
{
	ctc_tty_info *info = (ctc_tty_info *) tty->driver_data;

	if (ctc_tty_paranoia_check(info, tty->device, "ctc_tty_unthrottle"))
		return;
	info->mcr |= UART_MCR_RTS;
	if (I_IXOFF(tty))
		ctc_tty_inject(info, START_CHAR(tty));
	ctc_tty_transmit_status(info);
}

/*
 * ------------------------------------------------------------
 * ctc_tty_ioctl() and friends
 * ------------------------------------------------------------
 */

/*
 * ctc_tty_get_lsr_info - get line status register info
 *
 * Purpose: Let user call ioctl() to get info when the UART physically
 *          is emptied.  On bus types like RS485, the transmitter must
 *          release the bus after transmitting. This must be done when
 *          the transmit shift register is empty, not be done when the
 *          transmit holding register is empty.  This functionality
 *          allows RS485 driver to be written in user space.
 */
static int
ctc_tty_get_lsr_info(ctc_tty_info * info, uint * value)
{
	u_char status;
	uint result;
	ulong flags;

	save_flags(flags);
	cli();
	status = info->lsr;
	restore_flags(flags);
	result = ((status & UART_LSR_TEMT) ? TIOCSER_TEMT : 0);
	put_user(result, (uint *) value);
	return 0;
}


static int
ctc_tty_get_ctc_tty_info(ctc_tty_info * info, uint * value)
{
	u_char control,
	 status;
	uint result;
	ulong flags;

	control = info->mcr;
	save_flags(flags);
	cli();
	status = info->msr;
	restore_flags(flags);
	result = ((control & UART_MCR_RTS) ? TIOCM_RTS : 0)
	    | ((control & UART_MCR_DTR) ? TIOCM_DTR : 0)
	    | ((status & UART_MSR_DCD) ? TIOCM_CAR : 0)
	    | ((status & UART_MSR_RI) ? TIOCM_RNG : 0)
	    | ((status & UART_MSR_DSR) ? TIOCM_DSR : 0)
	    | ((status & UART_MSR_CTS) ? TIOCM_CTS : 0);
	put_user(result, (uint *) value);
	return 0;
}

static int
ctc_tty_set_ctc_tty_info(ctc_tty_info * info, uint cmd, uint * value)
{
	uint arg;
	int old_mcr = info->mcr & (UART_MCR_RTS | UART_MCR_DTR);

	get_user(arg, (uint *) value);
	switch (cmd) {
		case TIOCMBIS:
#ifdef CTC_DEBUG_MODEM_IOCTL
			printk(KERN_DEBUG "%s%d ioctl TIOCMBIS\n", CTC_TTY_NAME,
			       info->line);
#endif
			if (arg & TIOCM_RTS)
				info->mcr |= UART_MCR_RTS;
			if (arg & TIOCM_DTR)
				info->mcr |= UART_MCR_DTR;
			break;
		case TIOCMBIC:
#ifdef CTC_DEBUG_MODEM_IOCTL
			printk(KERN_DEBUG "%s%d ioctl TIOCMBIC\n", CTC_TTY_NAME,
			       info->line);
#endif
			if (arg & TIOCM_RTS)
				info->mcr &= ~UART_MCR_RTS;
			if (arg & TIOCM_DTR)
				info->mcr &= ~UART_MCR_DTR;
			break;
		case TIOCMSET:
#ifdef CTC_DEBUG_MODEM_IOCTL
			printk(KERN_DEBUG "%s%d ioctl TIOCMSET\n", CTC_TTY_NAME,
			       info->line);
#endif
			info->mcr = ((info->mcr & ~(UART_MCR_RTS | UART_MCR_DTR))
				 | ((arg & TIOCM_RTS) ? UART_MCR_RTS : 0)
			       | ((arg & TIOCM_DTR) ? UART_MCR_DTR : 0));
			break;
		default:
			return -EINVAL;
	}
	if ((info->mcr  & (UART_MCR_RTS | UART_MCR_DTR)) != old_mcr)
		ctc_tty_transmit_status(info);
	return 0;
}

static int
ctc_tty_ioctl(struct tty_struct *tty, struct file *file,
	       uint cmd, ulong arg)
{
	ctc_tty_info *info = (ctc_tty_info *) tty->driver_data;
	int error;
	int retval;

	if (ctc_tty_paranoia_check(info, tty->device, "ctc_tty_ioctl"))
		return -ENODEV;
	if (tty->flags & (1 << TTY_IO_ERROR))
		return -EIO;
	switch (cmd) {
		case TCSBRK:   /* SVID version: non-zero arg --> no break */
#ifdef CTC_DEBUG_MODEM_IOCTL
			printk(KERN_DEBUG "%s%d ioctl TCSBRK\n", CTC_TTY_NAME, info->line);
#endif
			retval = tty_check_change(tty);
			if (retval)
				return retval;
			tty_wait_until_sent(tty, 0);
			return 0;
		case TCSBRKP:  /* support for POSIX tcsendbreak() */
#ifdef CTC_DEBUG_MODEM_IOCTL
			printk(KERN_DEBUG "%s%d ioctl TCSBRKP\n", CTC_TTY_NAME, info->line);
#endif
			retval = tty_check_change(tty);
			if (retval)
				return retval;
			tty_wait_until_sent(tty, 0);
			return 0;
		case TIOCGSOFTCAR:
#ifdef CTC_DEBUG_MODEM_IOCTL
			printk(KERN_DEBUG "%s%d ioctl TIOCGSOFTCAR\n", CTC_TTY_NAME,
			       info->line);
#endif
			error = verify_area(VERIFY_WRITE, (void *) arg, sizeof(long));
			if (error)
				return error;
			put_user(C_CLOCAL(tty) ? 1 : 0, (ulong *) arg);
			return 0;
		case TIOCSSOFTCAR:
#ifdef CTC_DEBUG_MODEM_IOCTL
			printk(KERN_DEBUG "%s%d ioctl TIOCSSOFTCAR\n", CTC_TTY_NAME,
			       info->line);
#endif
			error = verify_area(VERIFY_READ, (void *) arg, sizeof(long));
			if (error)
				return error;
			get_user(arg, (ulong *) arg);
			tty->termios->c_cflag =
			    ((tty->termios->c_cflag & ~CLOCAL) |
			     (arg ? CLOCAL : 0));
			return 0;
		case TIOCMGET:
#ifdef CTC_DEBUG_MODEM_IOCTL
			printk(KERN_DEBUG "%s%d ioctl TIOCMGET\n", CTC_TTY_NAME,
			       info->line);
#endif
			error = verify_area(VERIFY_WRITE, (void *) arg, sizeof(uint));
			if (error)
				return error;
			return ctc_tty_get_ctc_tty_info(info, (uint *) arg);
		case TIOCMBIS:
		case TIOCMBIC:
		case TIOCMSET:
			error = verify_area(VERIFY_READ, (void *) arg, sizeof(uint));
			if (error)
				return error;
			return ctc_tty_set_ctc_tty_info(info, cmd, (uint *) arg);
		case TIOCSERGETLSR:	/* Get line status register */
#ifdef CTC_DEBUG_MODEM_IOCTL
			printk(KERN_DEBUG "%s%d ioctl TIOCSERGETLSR\n", CTC_TTY_NAME,
			       info->line);
#endif
			error = verify_area(VERIFY_WRITE, (void *) arg, sizeof(uint));
			if (error)
				return error;
			else
				return ctc_tty_get_lsr_info(info, (uint *) arg);
		default:
#ifdef CTC_DEBUG_MODEM_IOCTL
			printk(KERN_DEBUG "UNKNOWN ioctl 0x%08x on %s%d\n", cmd,
			       CTC_TTY_NAME, info->line);
#endif
			return -ENOIOCTLCMD;
	}
	return 0;
}

static void
ctc_tty_set_termios(struct tty_struct *tty, struct termios *old_termios)
{
	ctc_tty_info *info = (ctc_tty_info *) tty->driver_data;
	unsigned int cflag = tty->termios->c_cflag;

	ctc_tty_change_speed(info);

	/* Handle transition to B0 */
	if ((old_termios->c_cflag & CBAUD) && !(cflag & CBAUD)) {
		info->mcr &= ~(UART_MCR_DTR|UART_MCR_RTS);
		ctc_tty_transmit_status(info);
	}

	/* Handle transition from B0 to other */
	if (!(old_termios->c_cflag & CBAUD) && (cflag & CBAUD)) {
		info->mcr |= UART_MCR_DTR;
		if (!(tty->termios->c_cflag & CRTSCTS) ||
                    !test_bit(TTY_THROTTLED, &tty->flags)) {
                        info->mcr |= UART_MCR_RTS;
                }
		ctc_tty_transmit_status(info);
	}

	/* Handle turning off CRTSCTS */
	if ((old_termios->c_cflag & CRTSCTS) &&
            !(tty->termios->c_cflag & CRTSCTS))
                tty->hw_stopped = 0;
}

/*
 * ------------------------------------------------------------
 * ctc_tty_open() and friends
 * ------------------------------------------------------------
 */
static int