macserial.c

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				       SERIAL_XMIT_SIZE - info->xmit_head));
			memcpy(info->xmit_buf + info->xmit_head, tmp_buf, c);
			info->xmit_head = ((info->xmit_head + c) &
					   (SERIAL_XMIT_SIZE-1));
			info->xmit_cnt += c;
			restore_flags(flags);
			buf += c;
			count -= c;
			ret += c;
		}
		up(&tmp_buf_sem);
	} else {
		while (1) {
			save_flags(flags);
			cli();
			c = MIN(count,
				MIN(SERIAL_XMIT_SIZE - info->xmit_cnt - 1,
				    SERIAL_XMIT_SIZE - info->xmit_head));
			if (c <= 0) {
				restore_flags(flags);
				break;
			}
			memcpy(info->xmit_buf + info->xmit_head, buf, c);
			info->xmit_head = ((info->xmit_head + c) &
					   (SERIAL_XMIT_SIZE-1));
			info->xmit_cnt += c;
			restore_flags(flags);
			buf += c;
			count -= c;
			ret += c;
		}
	}
	if (info->xmit_cnt && !tty->stopped && !info->tx_stopped
	    && !info->tx_active)
		transmit_chars(info);
	return ret;
}

static int rs_write_room(struct tty_struct *tty)
{
	struct mac_serial *info = (struct mac_serial *)tty->driver_data;
	int	ret;

	if (serial_paranoia_check(info, tty->device, "rs_write_room"))
		return 0;
	ret = SERIAL_XMIT_SIZE - info->xmit_cnt - 1;
	if (ret < 0)
		ret = 0;
	return ret;
}

static int rs_chars_in_buffer(struct tty_struct *tty)
{
	struct mac_serial *info = (struct mac_serial *)tty->driver_data;

	if (serial_paranoia_check(info, tty->device, "rs_chars_in_buffer"))
		return 0;
	return info->xmit_cnt;
}

static void rs_flush_buffer(struct tty_struct *tty)
{
	struct mac_serial *info = (struct mac_serial *)tty->driver_data;
	unsigned long flags;

	if (serial_paranoia_check(info, tty->device, "rs_flush_buffer"))
		return;
	save_flags(flags); cli();
	info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;
	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);
}

/*
 * ------------------------------------------------------------
 * rs_throttle()
 * 
 * This routine is called by the upper-layer tty layer to signal that
 * incoming characters should be throttled.
 * ------------------------------------------------------------
 */
static void rs_throttle(struct tty_struct * tty)
{
	struct mac_serial *info = (struct mac_serial *)tty->driver_data;
	unsigned long flags;
#ifdef SERIAL_DEBUG_THROTTLE
	printk("throttle %ld....\n",tty->ldisc.chars_in_buffer(tty));
#endif

	if (serial_paranoia_check(info, tty->device, "rs_throttle"))
		return;

	if (I_IXOFF(tty)) {
		save_flags(flags); cli();
		info->x_char = STOP_CHAR(tty);
		if (!info->tx_active)
			transmit_chars(info);
		restore_flags(flags);
	}

	if (C_CRTSCTS(tty)) {
		/*
		 * Here we want to turn off the RTS line.  On Macintoshes,
		 * we only get the DTR line, which goes to both DTR and
		 * RTS on the modem.  RTS doesn't go out to the serial
		 * port socket.  So you should make sure your modem is
		 * set to ignore DTR if you're using CRTSCTS.
		 */
		save_flags(flags); cli();
		info->curregs[5] &= ~(DTR | RTS);
		info->pendregs[5] &= ~(DTR | RTS);
		write_zsreg(info->zs_channel, 5, info->curregs[5]);
		restore_flags(flags);
	}
}

static void rs_unthrottle(struct tty_struct * tty)
{
	struct mac_serial *info = (struct mac_serial *)tty->driver_data;
	unsigned long flags;
#ifdef SERIAL_DEBUG_THROTTLE
	printk("unthrottle %s: %d....\n",tty->ldisc.chars_in_buffer(tty));
#endif

	if (serial_paranoia_check(info, tty->device, "rs_unthrottle"))
		return;

	if (I_IXOFF(tty)) {
		save_flags(flags); cli();
		if (info->x_char)
			info->x_char = 0;
		else {
			info->x_char = START_CHAR(tty);
			if (!info->tx_active)
				transmit_chars(info);
		}
		restore_flags(flags);
	}

	if (C_CRTSCTS(tty)) {
		/* Assert RTS and DTR lines */
		save_flags(flags); cli();
		info->curregs[5] |= DTR | RTS;
		info->pendregs[5] |= DTR | RTS;
		write_zsreg(info->zs_channel, 5, info->curregs[5]);
		restore_flags(flags);
	}
}

/*
 * ------------------------------------------------------------
 * rs_ioctl() and friends
 * ------------------------------------------------------------
 */

static int get_serial_info(struct mac_serial * info,
			   struct serial_struct * retinfo)
{
	struct serial_struct tmp;
  
	if (!retinfo)
		return -EFAULT;
	memset(&tmp, 0, sizeof(tmp));
	tmp.type = info->type;
	tmp.line = info->line;
	tmp.port = info->port;
	tmp.irq = info->irq;
	tmp.flags = info->flags;
	tmp.baud_base = info->baud_base;
	tmp.close_delay = info->close_delay;
	tmp.closing_wait = info->closing_wait;
	tmp.custom_divisor = info->custom_divisor;
	if (copy_to_user(retinfo,&tmp,sizeof(*retinfo)))
		return -EFAULT;
	return 0;
}

static int set_serial_info(struct mac_serial * info,
			   struct serial_struct * new_info)
{
	struct serial_struct new_serial;
	struct mac_serial old_info;
	int 			retval = 0;

	if (copy_from_user(&new_serial,new_info,sizeof(new_serial)))
		return -EFAULT;
	old_info = *info;

	if (!capable(CAP_SYS_ADMIN)) {
		if ((new_serial.baud_base != info->baud_base) ||
		    (new_serial.type != info->type) ||
		    (new_serial.close_delay != info->close_delay) ||
		    ((new_serial.flags & ~ZILOG_USR_MASK) !=
		     (info->flags & ~ZILOG_USR_MASK)))
			return -EPERM;
		info->flags = ((info->flags & ~ZILOG_USR_MASK) |
			       (new_serial.flags & ZILOG_USR_MASK));
		info->custom_divisor = new_serial.custom_divisor;
		goto check_and_exit;
	}

	if (info->count > 1)
		return -EBUSY;

	/*
	 * OK, past this point, all the error checking has been done.
	 * At this point, we start making changes.....
	 */

	info->baud_base = new_serial.baud_base;
	info->flags = ((info->flags & ~ZILOG_FLAGS) |
			(new_serial.flags & ZILOG_FLAGS));
	info->type = new_serial.type;
	info->close_delay = new_serial.close_delay;
	info->closing_wait = new_serial.closing_wait;

check_and_exit:
	if (info->flags & ZILOG_INITIALIZED)
		retval = setup_scc(info);
	return retval;
}

/*
 * 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 an RS485 driver to be written in user space. 
 */
static int get_lsr_info(struct mac_serial * info, unsigned int *value)
{
	unsigned char status;
	unsigned long flags;

	save_flags(flags); cli();
	status = read_zsreg(info->zs_channel, 0);
	restore_flags(flags);
	status = (status & Tx_BUF_EMP)? TIOCSER_TEMT: 0;
	return put_user(status,value);
}

static int get_modem_info(struct mac_serial *info, unsigned int *value)
{
	unsigned char control, status;
	unsigned int result;
	unsigned long flags;

	save_flags(flags); cli();
	control = info->curregs[5];
	status = read_zsreg(info->zs_channel, 0);
	restore_flags(flags);
	result =  ((control & RTS) ? TIOCM_RTS: 0)
		| ((control & DTR) ? TIOCM_DTR: 0)
		| ((status  & DCD) ? TIOCM_CAR: 0)
		| ((status  & CTS) ? 0: TIOCM_CTS);
	return put_user(result,value);
}

static int set_modem_info(struct mac_serial *info, unsigned int cmd,
			  unsigned int *value)
{
	int error;
	unsigned int arg, bits;
	unsigned long flags;

	error = get_user(arg, value);
	if (error)
		return error;
	bits = (arg & TIOCM_RTS? RTS: 0) + (arg & TIOCM_DTR? DTR: 0);
	save_flags(flags); cli();
	switch (cmd) {
	case TIOCMBIS:
		info->curregs[5] |= bits;
		break;
	case TIOCMBIC:
		info->curregs[5] &= ~bits;
		break;
	case TIOCMSET:
		info->curregs[5] = (info->curregs[5] & ~(DTR | RTS)) | bits;
		break;
	default:
		restore_flags(flags);
		return -EINVAL;
	}
	info->pendregs[5] = info->curregs[5];
	write_zsreg(info->zs_channel, 5, info->curregs[5]);
	restore_flags(flags);
	return 0;
}

/*
 * rs_break - turn transmit break condition on/off
 */
static void rs_break(struct tty_struct *tty, int break_state)
{
	struct mac_serial *info = (struct mac_serial *) tty->driver_data;
	unsigned long flags;

	if (serial_paranoia_check(info, tty->device, "rs_break"))
		return;

	save_flags(flags); cli();
	if (break_state == -1)
		info->curregs[5] |= SND_BRK;
	else
		info->curregs[5] &= ~SND_BRK;
	write_zsreg(info->zs_channel, 5, info->curregs[5]);
	restore_flags(flags);
}

static int rs_ioctl(struct tty_struct *tty, struct file * file,
		    unsigned int cmd, unsigned long arg)
{
	struct mac_serial * info = (struct mac_serial *)tty->driver_data;

#ifdef CONFIG_KGDB
	if (info->kgdb_channel)
		return -ENODEV;
#endif
	if (serial_paranoia_check(info, tty->device, "rs_ioctl"))
		return -ENODEV;

	if ((cmd != TIOCGSERIAL) && (cmd != TIOCSSERIAL) &&
	    (cmd != TIOCSERCONFIG) && (cmd != TIOCSERGSTRUCT)) {
		if (tty->flags & (1 << TTY_IO_ERROR))
		    return -EIO;
	}

	switch (cmd) {
		case TIOCMGET:
			return get_modem_info(info, (unsigned int *) arg);
		case TIOCMBIS:
		case TIOCMBIC:
		case TIOCMSET:
			return set_modem_info(info, cmd, (unsigned int *) arg);
		case TIOCGSERIAL:
			return get_serial_info(info,
					       (struct serial_struct *) arg);
		case TIOCSSERIAL:
			return set_serial_info(info,
					       (struct serial_struct *) arg);
		case TIOCSERGETLSR: /* Get line status register */
			return get_lsr_info(info, (unsigned int *) arg);

		case TIOCSERGSTRUCT:
			if (copy_to_user((struct mac_serial *) arg,
					 info, sizeof(struct mac_serial)))
				return -EFAULT;
			return 0;

		default:
			return -ENOIOCTLCMD;
		}
	return 0;
}

static void rs_set_termios(struct tty_struct *tty, struct termios *old_termios)
{
	struct mac_serial *info = (struct mac_serial *)tty->driver_data;
	int was_stopped;

	if (tty->termios->c_cflag == old_termios->c_cflag)
		return;
	was_stopped = info->tx_stopped;

	change_speed(info, old_termios);

	if (was_stopped && !info->tx_stopped) {
		tty->hw_stopped = 0;
		rs_start(tty);
	}
}

/*
 * ------------------------------------------------------------
 * rs_close()
 * 
 * This routine is called when the serial port gets closed.
 * Wait for the last remaining data to be sent.
 * ------------------------------------------------------------
 */
static void rs_close(struct tty_struct *tty, struct file * filp)
{
	struct mac_serial * info = (struct mac_serial *)tty->driver_data;
	unsigned long flags;

	if (!info || serial_paranoia_check(info, tty->device, "rs_close"))
		return;

	save_flags(flags); cli();

	if (tty_hung_up_p(filp)) {
		MOD_DEC_USE_COUNT;
		restore_flags(flags);
		return;
	}

	OPNDBG("rs_close ttys%d, count = %d\n", info->line, info->count);
	if ((tty->count == 1) && (info->count != 1)) {
		/*
		 * Uh, oh.  tty->count is 1, which means that the tty
		 * structure will be freed.  Info->count should always
		 * be one in these conditions.  If it's greater than
		 * one, we've got real problems, since it means the
		 * serial port won't be shutdown.
		 */
		printk("rs_close: bad serial port count; tty->count is 1, "
		       "info->count is %d\n", info->count);
		info->count = 1;
	}
	if (--info->count < 0) {
		printk("rs_close: bad serial port count for ttys%d: %d\n",
		       info->line, info->count);
		info->count = 0;
	}
	if (info->count) {
		MOD_DEC_USE_COUNT;
		restore_flags(flags);
		return;
	}
	info->flags |= ZILOG_CLOSING;
	/*
	 * Save the termios structure, since this port may have
	 * separate termios for callout and dialin.
	 */
	if (info->flags & ZILOG_NORMAL_ACTIVE)
		info->normal_termios = *tty->termios;
	if (info->flags & ZILOG_CALLOUT_ACTIVE)
		info->callout_termios = *tty->termios;
	/*
	 * Now we wait for the transmit buffer to clear; and we notify 
	 * the line discipline to only process XON/XOFF characters.
	 */
	OPNDBG("waiting end of Tx... (timeout:%d)\n", info->closing_wait);
	tty->closing = 1;
	if (info->closing_wait != ZILOG_CLOSING_WAIT_NONE) {
		restore_flags(flags);
		tty_wait_until_sent(tty, info->closing_wait);
		save_flags(flags); cli();
	}

	/*
	 * At this point we stop accepting input.  To do this, we
	 * disable the receiver and receive interrupts.
	 */
	info->curregs[3] &= ~RxENABLE;
	info->pendregs[3] = info->curregs[3];
	write_zsreg(info->zs_channel, 3, info->curregs[3]);
	info->curregs[1] &= ~(0x18);	/* disable any rx ints */
	info->pendregs[1] = info->curregs[1];
	write_zsreg(info->zs_channel, 1, info->curregs[1]);
	ZS_CLEARFIFO(info->zs_channel);
	if (info->flags & ZILOG_INITIALIZED) {
		/*
		 * Before we drop DTR, make sure the SCC transmitter
		 * has completely drained.
		 */
		OPNDBG("waiting end of Rx...\n");
		restore_flags(flags);
		rs_wait_until_sent(tty, info->timeout);
		save_flags(flags); cli();
	}

	shutdown(info);
	/* restore flags now since shutdown() will have disabled this port's
	   specific irqs */
	restore_flags(flags);

	if (tty->driver.flush_buffer)
		tty->driver.flush_buffer(tty);
	if (tty->ldisc.flush_buffer)
		tty->ldisc.flush_buffer(tty);
	tty->closing = 0;
	info->event = 0;
	info->tty = 0;

	if (info->blocked_open) {
		if (info->close_delay) {
			current->state = TASK_INTERRUPTIBLE;
			schedule_timeout(info->close_delay);
		}
		wake_up_interruptible(&info->open_wait);
	}
	info->flags &= ~(ZILOG_NORMAL_ACTIVE|ZILOG_CALLOUT_ACTIVE|
			 ZILOG_CLOSING);
	wake_up_interruptible(&info->close_wait);
	MOD_DEC_USE_COUNT;
}