serial.c

基于16450/16550A的多串口驱动,估计很多人在找吧

	save_flags(flags); cli();
	if (info->xmit_cnt >= SERIAL_XMIT_SIZE - 1) {
		restore_flags(flags);
		return;
	}

	info->xmit_buf[info->xmit_head++] = ch;
	info->xmit_head &= SERIAL_XMIT_SIZE-1;
	info->xmit_cnt++;
	restore_flags(flags);
}

static void rs_flush_chars(struct tty_struct *tty)
{
	struct async_struct *info = (struct async_struct *)tty->driver_data;
	unsigned long flags;
				
	if (serial_paranoia_check(info, tty->device, "rs_flush_chars"))
		return;

	if (info->xmit_cnt <= 0 || tty->stopped || tty->hw_stopped ||
	    !info->xmit_buf)
		return;

	save_flags(flags); cli();
	info->IER |= UART_IER_THRI;
	serial_out(info, UART_IER, info->IER);
	restore_flags(flags);
}

static int rs_write(struct tty_struct * tty, int from_user,
		    const unsigned char *buf, int count)
{
	int	c, total = 0;
	struct async_struct *info = (struct async_struct *)tty->driver_data;
	unsigned long flags;
				
	if (serial_paranoia_check(info, tty->device, "rs_write"))
		return 0;

	if (!tty || !info->xmit_buf || !tmp_buf)
		return 0;
	    
	if (from_user)
		down(&tmp_buf_sem);
	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) {
			memcpy_fromfs(tmp_buf, buf, c);
			c = MIN(c, MIN(SERIAL_XMIT_SIZE - info->xmit_cnt - 1,
				       SERIAL_XMIT_SIZE - info->xmit_head));
			memcpy(info->xmit_buf + info->xmit_head, tmp_buf, c);
		} 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 (from_user)
		up(&tmp_buf_sem);
	if (info->xmit_cnt && !tty->stopped && !tty->hw_stopped &&
	    !(info->IER & UART_IER_THRI)) {
		info->IER |= UART_IER_THRI;
		serial_out(info, UART_IER, info->IER);
	}
	restore_flags(flags);
	return total;
}

static int rs_write_room(struct tty_struct *tty)
{
	struct async_struct *info = (struct async_struct *)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 async_struct *info = (struct async_struct *)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 async_struct *info = (struct async_struct *)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 async_struct *info = (struct async_struct *)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);

	info->MCR &= ~UART_MCR_RTS;
	info->MCR_noint &= ~UART_MCR_RTS;
	cli();
	serial_out(info, UART_MCR, info->MCR);
	sti();
}

static void rs_unthrottle(struct tty_struct * tty)
{
	struct async_struct *info = (struct async_struct *)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);
	}
	info->MCR |= UART_MCR_RTS;
	info->MCR_noint |= UART_MCR_RTS;
	cli();
	serial_out(info, UART_MCR, info->MCR);
	sti();
}

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

static int get_serial_info(struct async_struct * 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;
	tmp.hub6 = info->hub6;
	memcpy_tofs(retinfo,&tmp,sizeof(*retinfo));
	return 0;
}

static int set_serial_info(struct async_struct * info,
			   struct serial_struct * new_info)
{
	struct serial_struct new_serial;
	struct async_struct old_info;
	unsigned int		i,change_irq,change_port;
	int 			retval = 0;

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

	change_irq = new_serial.irq != info->irq;
	change_port = (new_serial.port != info->port) || (new_serial.hub6 != info->hub6);

	if (!suser()) {
		if (change_irq || change_port ||
		    (new_serial.baud_base != info->baud_base) ||
		    (new_serial.type != info->type) ||
		    (new_serial.close_delay != info->close_delay) ||
		    ((new_serial.flags & ~ASYNC_USR_MASK) !=
		     (info->flags & ~ASYNC_USR_MASK)))
			return -EPERM;
		info->flags = ((info->flags & ~ASYNC_USR_MASK) |
			       (new_serial.flags & ASYNC_USR_MASK));
		info->custom_divisor = new_serial.custom_divisor;
		goto check_and_exit;
	}

#ifndef CONFIG_COLDFIRE
	if (new_serial.irq == 2)
		new_serial.irq = 9;

	if ((new_serial.irq > 15) || (new_serial.port > 0xffff) ||
	    (new_serial.type < PORT_UNKNOWN) || (new_serial.type > PORT_MAX)) {
		return -EINVAL;
	}
#endif

	/* Make sure address is not already in use */
	if (new_serial.type) {
		for (i = 0 ; i < NR_PORTS; i++)
			if ((info != &rs_table[i]) &&
			    (rs_table[i].port == new_serial.port) &&
			    rs_table[i].type)
				return -EADDRINUSE;
	}

	if ((change_port || change_irq) && (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 & ~ASYNC_FLAGS) |
			(new_serial.flags & ASYNC_FLAGS));
	info->custom_divisor = new_serial.custom_divisor;
	info->type = new_serial.type;
	info->close_delay = new_serial.close_delay * HZ/100;
	info->closing_wait = new_serial.closing_wait * HZ/100;

	release_region(info->port,8);
	if (change_port || change_irq) {
		/*
		 * We need to shutdown the serial port at the old
		 * port/irq combination.
		 */
		shutdown(info);
		info->irq = new_serial.irq;
		info->port = new_serial.port;
		info->hub6 = new_serial.hub6;
	}
	if(info->type != PORT_UNKNOWN)
		request_region(info->port,8,"serial(set)");

	
check_and_exit:
	if (!info->port || !info->type)
		return 0;
	if (info->flags & ASYNC_INITIALIZED) {
		if (((old_info.flags & ASYNC_SPD_MASK) !=
		     (info->flags & ASYNC_SPD_MASK)) ||
		    (old_info.custom_divisor != info->custom_divisor))
			change_speed(info);
	} else
		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 async_struct * info, unsigned int *value)
{
	unsigned char status;
	unsigned int result;

	cli();
	status = serial_in(info, UART_LSR);
	sti();
	result = ((status & UART_LSR_TEMT) ? TIOCSER_TEMT : 0);
	put_user(result,value);
	return 0;
}


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

	control = info->MCR;
	cli();
	status = serial_in(info, UART_MSR);
	sti();
	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,value);
	return 0;
}

static int set_modem_info(struct async_struct * info, unsigned int cmd,
			  unsigned int *value)
{
	int error;
	unsigned int arg;

	error = verify_area(VERIFY_READ, value, sizeof(int));
	if (error)
		return error;
	arg = get_user(value);
	switch (cmd) {
	case TIOCMBIS: 
		if (arg & TIOCM_RTS) {
			info->MCR |= UART_MCR_RTS;
			info->MCR_noint |= UART_MCR_RTS;
		}
		if (arg & TIOCM_DTR) {
			info->MCR |= UART_MCR_DTR;
			info->MCR_noint |= UART_MCR_DTR;
		}
		break;
	case TIOCMBIC:
		if (arg & TIOCM_RTS) {
			info->MCR &= ~UART_MCR_RTS;
			info->MCR_noint &= ~UART_MCR_RTS;
		}
		if (arg & TIOCM_DTR) {
			info->MCR &= ~UART_MCR_DTR;
			info->MCR_noint &= ~UART_MCR_DTR;
		}
		break;
	case TIOCMSET:
		info->MCR = ((info->MCR & ~(UART_MCR_RTS | UART_MCR_DTR))
			     | ((arg & TIOCM_RTS) ? UART_MCR_RTS : 0)
			     | ((arg & TIOCM_DTR) ? UART_MCR_DTR : 0));
		info->MCR_noint = ((info->MCR_noint
				    & ~(UART_MCR_RTS | UART_MCR_DTR))
				   | ((arg & TIOCM_RTS) ? UART_MCR_RTS : 0)
				   | ((arg & TIOCM_DTR) ? UART_MCR_DTR : 0));
		break;
	default:
		return -EINVAL;
	}
	cli();
	serial_out(info, UART_MCR, info->MCR);
	sti();
	return 0;
}

static int do_autoconfig(struct async_struct * info)
{
	int			retval;
	
	if (!suser())
		return -EPERM;
	
	if (info->count > 1)
		return -EBUSY;
	
	shutdown(info);

	cli();
	autoconfig(info);
	sti();

	retval = startup(info);
	if (retval)
		return retval;
	return 0;
}


/*
 * rs_break() --- routine which turns the break handling on or off
 * adapted from 2.1.124
 */
static void rs_break(struct async_struct * info, int break_state)
{
        unsigned long flags;
        
        if (!info->port)
                return;
        save_flags(flags);cli();
        if (break_state == -1)
                serial_out(info, UART_LCR,
                           serial_inp(info, UART_LCR) | UART_LCR_SBC);
        else
                serial_out(info, UART_LCR,
                           serial_inp(info, UART_LCR) & ~UART_LCR_SBC);
        restore_flags(flags);
}

/*
 * This routine sends a break character out the serial port.
 */
static void send_break(	struct async_struct * info, int duration)
{
	if (!info->port)
		return;
	current->state = TASK_INTERRUPTIBLE;
	current->timeout = jiffies + duration;
	cli();
	serial_out(info, UART_LCR, serial_inp(info, UART_LCR) | UART_LCR_SBC);
	schedule();
	serial_out(info, UART_LCR, serial_inp(info, UART_LCR) & ~UART_LCR_SBC);
	sti();
}

#ifndef CONFIG_COLDFIRE
/*
 * This routine returns a bitfield of "wild interrupts".  Basically,
 * any unclaimed interrupts which is flapping around.
 */
static int check_wild_interrupts(int doprint)
{
	int	i, mask;
	int	wild_interrupts = 0;
	int	irq_lines;
	unsigned long timeout;
	unsigned long flags;
	
	/* Turn on interrupts (they may be off) */
	save_flags(flags); sti();

	irq_lines = grab_all_interrupts(0);
	
	/*
	 * Delay for 0.1 seconds -- we use a busy loop since this may 
	 * occur during the bootup sequence
	 */
	timeout = jiffies+HZ/10;
	while (timeout >= jiffies)
		;
	
	rs_triggered = 0;	/* Reset after letting things settle */

	timeout = jiffies+HZ/10;
	while (timeout >= jiffies)
		;
	
	for (i = 0, mask = 1; i < 16; i++, mask <<= 1) {
		if ((rs_triggered & (1 << i)) &&
		    (irq_lines & (1 << i))) {
			wild_interrupts |= mask;
			if (doprint)
				printk("Wild interrupt?  (IRQ %d)\n", i);
		}
	}
	free_all_interrupts(irq_lines);