serial.c

arm平台上的uclinux系统全部源代码

	save_flags_cli(flags); /* Disable interrupts */

	/*
	 * clear delta_msr_wait queue to avoid mem leaks: we may free the irq
	 * here so the queue might never be waken up
	 */
	wake_up_interruptible(&info->delta_msr_wait);
	
	/*
	 * First unlink the serial port from the IRQ chain...
	 */
	if (info->next_port)
		info->next_port->prev_port = info->prev_port;
	if (info->prev_port)
		info->prev_port->next_port = info->next_port;
	else
		IRQ_ports[info->irq] = info->next_port;
	figure_IRQ_timeout(info->irq);
	
	/*
	 * Free the IRQ, if necessary
	 */
	if (info->irq && (!IRQ_ports[info->irq] ||
			  !IRQ_ports[info->irq]->next_port)) {
		if (IRQ_ports[info->irq]) {
			free_irq(info->irq, NULL);
			retval = request_irq(info->irq, rs_interrupt_single,
					     IRQ_T(info), "serial", NULL);
			
			if (retval)
				printk("serial shutdown: request_irq: error %d"
				       "  Couldn't reacquire IRQ.\n", retval);
		} else
			free_irq(info->irq, NULL);
	}

	if (info->xmit_buf) {
		free_page((unsigned long) info->xmit_buf);
		info->xmit_buf = 0;
	}

	info->IER = 0;
	serial_outp(info, UART_IER, 0x00);	/* disable all intrs */
	if (info->flags & ASYNC_FOURPORT) {
		/* reset interrupts on the AST Fourport board */
		(void) inb((info->port & 0xFE0) | 0x01F);
	}
	
	if (!info->tty || (info->tty->termios->c_cflag & HUPCL)) {
		info->MCR &= ~(UART_MCR_DTR|UART_MCR_RTS);
		info->MCR_noint &= ~(UART_MCR_DTR|UART_MCR_RTS);
	}
	serial_outp(info, UART_MCR, info->MCR_noint);

	/* disable FIFO's */	
	serial_outp(info, UART_FCR, (UART_FCR_CLEAR_RCVR |
				     UART_FCR_CLEAR_XMIT));
	(void)serial_in(info, UART_RX);    /* read data port to reset things */
	
	if (info->tty)
		set_bit(TTY_IO_ERROR, &info->tty->flags);
	
	info->flags &= ~ASYNC_INITIALIZED;
	restore_flags(flags);
}

/*
 * This routine is called to set the UART divisor registers to match
 * the specified baud rate for a serial port.
 */
static void change_speed(struct async_struct *info)
{
	unsigned short port;
	int	quot = 0;
	unsigned cflag,cval,fcr;
	int	i;

	if (!info->tty || !info->tty->termios)
		return;
	cflag = info->tty->termios->c_cflag;
	if (!(port = info->port))
		return;
	i = cflag & CBAUD;
	if (i & CBAUDEX) {
		i &= ~CBAUDEX;
		if (i < 1 || i > 2) 
			info->tty->termios->c_cflag &= ~CBAUDEX;
		else
			i += 15;
	}
	if (i == 15) {
		if ((info->flags & ASYNC_SPD_MASK) == ASYNC_SPD_HI)
			i += 1;
		if ((info->flags & ASYNC_SPD_MASK) == ASYNC_SPD_VHI)
			i += 2;
		if ((info->flags & ASYNC_SPD_MASK) == ASYNC_SPD_CUST)
			quot = info->custom_divisor;
	}
	if (quot) {
		info->timeout = ((info->xmit_fifo_size*HZ*15*quot) /
				 info->baud_base) + 2;
	} else if (baud_table[i] == 134) {
		quot = (2*info->baud_base / 269);
		info->timeout = (info->xmit_fifo_size*HZ*30/269) + 2;
	} else if (baud_table[i]) {
		quot = info->baud_base / baud_table[i];
		info->timeout = (info->xmit_fifo_size*HZ*15/baud_table[i]) + 2;
	} else {
		quot = 0;
		info->timeout = 0;
	}
	if (quot) {
		info->MCR |= UART_MCR_DTR;
		info->MCR_noint |= UART_MCR_DTR;
		cli();
		serial_out(info, UART_MCR, info->MCR);
		sti();
	} else {
		info->MCR &= ~UART_MCR_DTR;
		info->MCR_noint &= ~UART_MCR_DTR;
		cli();
		serial_out(info, UART_MCR, info->MCR);
		sti();
		return;
	}
	/* byte size and parity */
	switch (cflag & CSIZE) {
	      case CS5: cval = 0x00; break;
	      case CS6: cval = 0x01; break;
	      case CS7: cval = 0x02; break;
	      case CS8: cval = 0x03; break;
	      default:  cval = 0x00; break;	/* too keep GCC shut... */
	}
	if (cflag & CSTOPB) {
		cval |= 0x04;
	}
	if (cflag & PARENB)
		cval |= UART_LCR_PARITY;
	if (!(cflag & PARODD))
		cval |= UART_LCR_EPAR;
	if (info->type == PORT_16550A) {
		if ((info->baud_base / quot) < 2400)
			fcr = UART_FCR_ENABLE_FIFO | UART_FCR_TRIGGER_1;
		else
			fcr = UART_FCR_ENABLE_FIFO | UART_FCR_TRIGGER_8;
	} else if (info->type == PORT_16650) {
		/*
		 * On the 16650, we disable the FIFOs altogether
		 * because of a design bug in how the implement
		 * things.  We could support it by completely changing
		 * how we handle the interrupt driver, but not today....
		 *
		 * N.B.  Because there's no way to set a FIFO trigger
		 * at 1 char, we'd probably disable at speed below
		 * 2400 baud anyway...
		 */
		fcr = 0;
	} else
		fcr = 0;
	
	/* CTS flow control flag and modem status interrupts */
	info->IER &= ~UART_IER_MSI;
	if (cflag & CRTSCTS) {
		info->flags |= ASYNC_CTS_FLOW;
		info->IER |= UART_IER_MSI;
	} else
		info->flags &= ~ASYNC_CTS_FLOW;
	if (cflag & CLOCAL)
		info->flags &= ~ASYNC_CHECK_CD;
	else {
		info->flags |= ASYNC_CHECK_CD;
		info->IER |= UART_IER_MSI;
	}
	serial_out(info, UART_IER, info->IER);

	/*
	 * Set up parity check flag
	 */
#define RELEVANT_IFLAG(iflag) (iflag & (IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK))

	info->read_status_mask = UART_LSR_OE | UART_LSR_THRE | UART_LSR_DR;
	if (I_INPCK(info->tty))
		info->read_status_mask |= UART_LSR_FE | UART_LSR_PE;
	if (I_BRKINT(info->tty) || I_PARMRK(info->tty))
		info->read_status_mask |= UART_LSR_BI;
	
	info->ignore_status_mask = 0;
#if 0
	/* This should be safe, but for some broken bits of hardware... */
	if (I_IGNPAR(info->tty)) {
		info->ignore_status_mask |= UART_LSR_PE | UART_LSR_FE;
		info->read_status_mask |= UART_LSR_PE | UART_LSR_FE;
	}
#endif
	if (I_IGNBRK(info->tty)) {
		info->ignore_status_mask |= UART_LSR_BI;
		info->read_status_mask |= UART_LSR_BI;
		/*
		 * If we're ignore parity and break indicators, ignore 
		 * overruns too.  (For real raw support).
		 */
		if (I_IGNPAR(info->tty)) {
			info->ignore_status_mask |= UART_LSR_OE |
				UART_LSR_PE | UART_LSR_FE;
			info->read_status_mask |= UART_LSR_OE |
				UART_LSR_PE | UART_LSR_FE;
		}
	}
	cli();
	serial_outp(info, UART_LCR, cval | UART_LCR_DLAB);	/* set DLAB */
	serial_outp(info, UART_DLL, quot & 0xff);	/* LS of divisor */
	serial_outp(info, UART_DLM, quot >> 8);		/* MS of divisor */
	serial_outp(info, UART_LCR, cval);		/* reset DLAB */
	serial_outp(info, UART_FCR, fcr); 	/* set fcr */
	sti();
}

static void rs_put_char(struct tty_struct *tty, unsigned char ch)
{
	struct async_struct *info = (struct async_struct *)tty->driver_data;
	unsigned long flags;

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

	if (!tty || !info->xmit_buf)
		return;

	save_flags_cli (flags);
	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_cli (flags);
	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;
	}
#if 0
	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;
	}
#else
	if ((new_serial.irq > 31) || (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;