trioserial.c

arm平台上的uclinux系统全部源代码

	/*printk("rs_write of %d bytes\n", count);*/


	save_flags(flags);
	while (1) {
		cli();		
		c = MIN(count, MIN(SERIAL_XMIT_SIZE - info->xmit_cnt - 1,
				   SERIAL_XMIT_SIZE - info->xmit_head));
		if (c <= 0)
			break;

		if (from_user) {
			down(&tmp_buf_sem);
			memcpy_fromfs(tmp_buf, buf, c);
			
#if 0		// HN already done			
			c = MIN(c, MIN(SERIAL_XMIT_SIZE - info->xmit_cnt - 1,
				       SERIAL_XMIT_SIZE - info->xmit_head));
#endif			
			memcpy(info->xmit_buf + info->xmit_head, tmp_buf, c);
			up(&tmp_buf_sem);
		} else
			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;
		total += c;
	}

	if (info->xmit_cnt && !tty->stopped && !tty->hw_stopped ){
		/* Enable transmitter */
		
		cli();		
		/*printk("Enabling transmitter\n");*/

		if(!info->use_ints){	
			while(info->xmit_cnt) {
				wait_EOT(info->uart);
				/* Send char */
				xmit_char(info, info->xmit_buf[info->xmit_tail++]);
				wait_EOT(info->uart);
				info->xmit_tail = info->xmit_tail & (SERIAL_XMIT_SIZE-1);
				info->xmit_cnt--;
			}
		}else{
			if (info->xmit_cnt){
				/* Send char */
				wait_EOT(info->uart);
				xmit_string(info, &info->xmit_buf[info->xmit_tail], info->xmit_cnt);
				info->xmit_tail = info->xmit_tail & (SERIAL_XMIT_SIZE-1);
				info->xmit_cnt=0;
			}
		}
		restore_flags(flags);
	} else {
		/*printk("Skipping transmit\n");*/
	}


#if 0
		printk("Enabling stuff anyhow\n");
		tx_start(0);

		if (SCC_EOT(0,0)) {
			printk("TX FIFO empty.\n");
			/* Send char */
			trio_xmit_char(info->uart, info->xmit_buf[info->xmit_tail++]);
			info->xmit_tail = info->xmit_tail & (SERIAL_XMIT_SIZE-1);
			info->xmit_cnt--;
		}
#endif

	restore_flags(flags);
	return total;
}

static int rs_write_room(struct tty_struct *tty)
{
	struct trio_serial *info = (struct trio_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 trio_serial *info = (struct trio_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 trio_serial *info = (struct trio_serial *)tty->driver_data;
				
	if (serial_paranoia_check(info, tty->device, "rs_flush_buffer"))
		return;
	cli();
	info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;
	sti();
	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 trio_serial *info = (struct trio_serial *)tty->driver_data;
#ifdef SERIAL_DEBUG_THROTTLE
	char	buf[64];
	
	printk("throttle %s: %d....\n", _tty_name(tty, buf),
	       tty->ldisc.chars_in_buffer(tty));
#endif

	if (serial_paranoia_check(info, tty->device, "rs_throttle"))
		return;
	
	if (I_IXOFF(tty))
		info->x_char = STOP_CHAR(tty);

	/* Turn off RTS line (do this atomic) */
}

static void rs_unthrottle(struct tty_struct * tty)
{
	struct trio_serial *info = (struct trio_serial *)tty->driver_data;
#ifdef SERIAL_DEBUG_THROTTLE
	char	buf[64];
	
	printk("unthrottle %s: %d....\n", _tty_name(tty, buf),
	       tty->ldisc.chars_in_buffer(tty));
#endif

	if (serial_paranoia_check(info, tty->device, "rs_unthrottle"))
		return;
	
	if (I_IXOFF(tty)) {
		if (info->x_char)
			info->x_char = 0;
		else
			info->x_char = START_CHAR(tty);
	}

	/* Assert RTS line (do this atomic) */
}

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

static int get_serial_info(struct trio_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.irq = info->irq;
	tmp.port = info->port;
	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;
	memcpy_tofs(retinfo,&tmp,sizeof(*retinfo));
	return 0;
}

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

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

	if (!suser()) {
		if ((new_serial.baud_base != info->baud_base) ||
		    (new_serial.type != info->type) ||
		    (new_serial.close_delay != info->close_delay) ||
		    ((new_serial.flags & ~S_USR_MASK) !=
		     (info->flags & ~S_USR_MASK)))
			return -EPERM;
		info->flags = ((info->flags & ~S_USR_MASK) |
			       (new_serial.flags & S_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 & ~S_FLAGS) |
			(new_serial.flags & S_FLAGS));
	info->type = new_serial.type;
	info->close_delay = new_serial.close_delay;
	info->closing_wait = new_serial.closing_wait;

check_and_exit:
	retval = startup(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 trio_serial * info, unsigned int *value)
{
	unsigned char status;

	cli();
	status = info->uart->csr;
	status &= US_TXEMPTY;
	sti();
	put_user(status,value);
	return 0;
}

/*
 * This routine sends a break character out the serial port.
 */
static void send_break(	struct trio_serial * info, int duration)
{
	current->state = TASK_INTERRUPTIBLE;
	current->timeout = jiffies + duration;
	cli();
	info->uart->cr |= US_STTBRK;
	if(!info->use_ints){
		while(US_TXRDY != (info->uart->csr & US_TXRDY)){
			;			// this takes max 2ms at 9600
		}
		info->uart->cr |= US_STTBRK;
	}
	sti();
}

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

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

	if ((cmd != TIOCGSERIAL) && (cmd != TIOCSSERIAL) &&
	    (cmd != TIOCSERCONFIG) && (cmd != TIOCSERGWILD)  &&
	    (cmd != TIOCSERSWILD) && (cmd != TIOCSERGSTRUCT)) {
		if (tty->flags & (1 << TTY_IO_ERROR))
		    return -EIO;
	}
	
	switch (cmd) {
		case TCSBRK:	/* SVID version: non-zero arg --> no break */
			retval = tty_check_change(tty);
			if (retval)
				return retval;
			tty_wait_until_sent(tty, 0);
			if (!arg)
				send_break(info, HZ/4);	/* 1/4 second */
			return 0;
		case TCSBRKP:	/* support for POSIX tcsendbreak() */
			retval = tty_check_change(tty);
			if (retval)
				return retval;
			tty_wait_until_sent(tty, 0);
			send_break(info, arg ? arg*(HZ/10) : HZ/4);
			return 0;
		case TIOCGSOFTCAR:
			error = verify_area(VERIFY_WRITE, (void *) arg,sizeof(long));
			if (error)
				return error;
			put_fs_long(C_CLOCAL(tty) ? 1 : 0,
				    (unsigned long *) arg);
			return 0;
		case TIOCSSOFTCAR:
			arg = get_fs_long((unsigned long *) arg);
			tty->termios->c_cflag =
				((tty->termios->c_cflag & ~CLOCAL) |
				 (arg ? CLOCAL : 0));
			return 0;
		case TIOCGSERIAL:
			error = verify_area(VERIFY_WRITE, (void *) arg,
						sizeof(struct serial_struct));
			if (error)
				return error;
			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 */
			error = verify_area(VERIFY_WRITE, (void *) arg,
				sizeof(unsigned int));
			if (error)
				return error;
			else
			    return get_lsr_info(info, (unsigned int *) arg);

		case TIOCSERGSTRUCT:
			error = verify_area(VERIFY_WRITE, (void *) arg,
						sizeof(struct trio_serial));
			if (error)
				return error;
			memcpy_tofs((struct trio_serial *) arg,
				    info, sizeof(struct trio_serial));
			return 0;
			
		default:
			return -ENOIOCTLCMD;
		}
	return 0;
}

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

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

	change_speed(info);

	if ((old_termios->c_cflag & CRTSCTS) &&
	    !(tty->termios->c_cflag & CRTSCTS)) {
		tty->hw_stopped = 0;
		rs_start(tty);
	}
	
}

/*
 * ------------------------------------------------------------
 * rs_close()
 * 
 * This routine is called when the serial port gets closed.  First, we
 * wait for the last remaining data to be sent.  Then, we unlink its
 * S structure from the interrupt chain if necessary, and we free
 * that IRQ if nothing is left in the chain.
 * ------------------------------------------------------------
 */
static void rs_close(struct tty_struct *tty, struct file * filp)
{
	struct trio_serial * info = (struct trio_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)) {
		restore_flags(flags);
		return;
	}
	
#ifdef SERIAL_DEBUG_OPEN
	printk("rs_close ttyS%d, count = %d\n", info->line, info->count);
#endif
	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) {
		restore_flags(flags);
		return;
	}
	// closing port so disable interrupts
	set_ints_mode(0, info);
	
	info->flags |= S_CLOSING;
	/*
	 * Save the termios structure, since this port may have
	 * separate termios for callout and dialin.
	 */
	if (info->flags & S_NORMAL_ACTIVE)
		info->normal_termios = *tty->termios;
	if (info->flags & S_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.
	 */
	tty->closing = 1;
	if (info->closing_wait != S_CLOSING_WAIT_NONE)
		tty_wait_until_sent(tty, info->closing_wait);
	/*
	 * At this point we stop accepting input.  To do this, we
	 * disable the receive line status interrupts, and tell the
	 * interrupt driver to stop checking the data ready bit in the
	 * line status register.
	 */

	shutdown(info);
	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 (tty->ldisc.num != ldiscs[N_TTY].num) {
		if (tty->ldisc.close)
			(tty->ldisc.close)(tty);
		tty->ldisc = ldiscs[N_TTY];
		tty->termios->c_line = N_TTY;
		if (tty->ldisc.open)
			(tty->ldisc.open)(tty);
	}
	if (info->blocked_open) {
		if (info->close_delay) {
			current->state = TASK_INTERRUPTIBLE;
			current->timeout = jiffies + info->close_delay;
			schedule();