serial.c

上传linux-jx2410的源代码

		if (info->close_delay) {
			set_current_state(TASK_INTERRUPTIBLE);
			schedule_timeout(info->close_delay);
		}
		wake_up_interruptible(&info->open_wait);
	}
	info->flags &= ~(ASYNC_NORMAL_ACTIVE|ASYNC_CALLOUT_ACTIVE|
			 ASYNC_CLOSING);
	wake_up_interruptible(&info->close_wait);
	MOD_DEC_USE_COUNT;
}

/*
 * rs_wait_until_sent() --- wait until the transmitter is empty
 */
static void rs_wait_until_sent(struct tty_struct *tty, int timeout)
{
	struct async_struct * info = (struct async_struct *)tty->driver_data;
	unsigned long orig_jiffies, char_time;
	int lsr;
	
	if (serial_paranoia_check(info, tty->device, "rs_wait_until_sent"))
		return;

	if (info->state->type == PORT_UNKNOWN)
		return;

	if (info->xmit_fifo_size == 0)
		return; /* Just in case.... */

	orig_jiffies = jiffies;
	/*
	 * Set the check interval to be 1/5 of the estimated time to
	 * send a single character, and make it at least 1.  The check
	 * interval should also be less than the timeout.
	 * 
	 * Note: we have to use pretty tight timings here to satisfy
	 * the NIST-PCTS.
	 */
	char_time = (info->timeout - HZ/50) / info->xmit_fifo_size;
	char_time = char_time / 5;
	if (char_time == 0)
		char_time = 1;
	if (timeout && timeout < char_time)
		char_time = timeout;
	/*
	 * If the transmitter hasn't cleared in twice the approximate
	 * amount of time to send the entire FIFO, it probably won't
	 * ever clear.  This assumes the UART isn't doing flow
	 * control, which is currently the case.  Hence, if it ever
	 * takes longer than info->timeout, this is probably due to a
	 * UART bug of some kind.  So, we clamp the timeout parameter at
	 * 2*info->timeout.
	 */
	if (!timeout || timeout > 2*info->timeout)
		timeout = 2*info->timeout;
#ifdef SERIAL_DEBUG_RS_WAIT_UNTIL_SENT
	printk("In rs_wait_until_sent(%d) check=%lu...", timeout, char_time);
	printk("jiff=%lu...", jiffies);
#endif
	while (!((lsr = serial_inp(info, UART_LSR)) & UART_LSR_TEMT)) {
#ifdef SERIAL_DEBUG_RS_WAIT_UNTIL_SENT
		printk("lsr = %d (jiff=%lu)...", lsr, jiffies);
#endif
		set_current_state(TASK_INTERRUPTIBLE);
		schedule_timeout(char_time);
		if (signal_pending(current))
			break;
		if (timeout && time_after(jiffies, orig_jiffies + timeout))
			break;
	}
	set_current_state(TASK_RUNNING);
#ifdef SERIAL_DEBUG_RS_WAIT_UNTIL_SENT
	printk("lsr = %d (jiff=%lu)...done\n", lsr, jiffies);
#endif
}

/*
 * rs_hangup() --- called by tty_hangup() when a hangup is signaled.
 */
static void rs_hangup(struct tty_struct *tty)
{
	struct async_struct * info = (struct async_struct *)tty->driver_data;
	struct serial_state *state = info->state;
	
	if (serial_paranoia_check(info, tty->device, "rs_hangup"))
		return;

	state = info->state;
	
	rs_flush_buffer(tty);
	if (info->flags & ASYNC_CLOSING)
		return;
	shutdown(info);
	info->event = 0;
	state->count = 0;
	info->flags &= ~(ASYNC_NORMAL_ACTIVE|ASYNC_CALLOUT_ACTIVE);
	info->tty = 0;
	wake_up_interruptible(&info->open_wait);
}

/*
 * ------------------------------------------------------------
 * rs_open() and friends
 * ------------------------------------------------------------
 */
static int block_til_ready(struct tty_struct *tty, struct file * filp,
			   struct async_struct *info)
{
	DECLARE_WAITQUEUE(wait, current);
	struct serial_state *state = info->state;
	int		retval;
	int		do_clocal = 0, extra_count = 0;
	unsigned long	flags;

	/*
	 * If the device is in the middle of being closed, then block
	 * until it's done, and then try again.
	 */
	if (tty_hung_up_p(filp) ||
	    (info->flags & ASYNC_CLOSING)) {
		if (info->flags & ASYNC_CLOSING)
			interruptible_sleep_on(&info->close_wait);
#ifdef SERIAL_DO_RESTART
		return ((info->flags & ASYNC_HUP_NOTIFY) ?
			-EAGAIN : -ERESTARTSYS);
#else
		return -EAGAIN;
#endif
	}

	/*
	 * If this is a callout device, then just make sure the normal
	 * device isn't being used.
	 */
	if (tty->driver.subtype == SERIAL_TYPE_CALLOUT) {
		if (info->flags & ASYNC_NORMAL_ACTIVE)
			return -EBUSY;
		if ((info->flags & ASYNC_CALLOUT_ACTIVE) &&
		    (info->flags & ASYNC_SESSION_LOCKOUT) &&
		    (info->session != current->session))
		    return -EBUSY;
		if ((info->flags & ASYNC_CALLOUT_ACTIVE) &&
		    (info->flags & ASYNC_PGRP_LOCKOUT) &&
		    (info->pgrp != current->pgrp))
		    return -EBUSY;
		info->flags |= ASYNC_CALLOUT_ACTIVE;
		return 0;
	}
	
	/*
	 * If non-blocking mode is set, or the port is not enabled,
	 * then make the check up front and then exit.
	 */
	if ((filp->f_flags & O_NONBLOCK) ||
	    (tty->flags & (1 << TTY_IO_ERROR))) {
		if (info->flags & ASYNC_CALLOUT_ACTIVE)
			return -EBUSY;
		info->flags |= ASYNC_NORMAL_ACTIVE;
		return 0;
	}

	if (info->flags & ASYNC_CALLOUT_ACTIVE) {
		if (state->normal_termios.c_cflag & CLOCAL)
			do_clocal = 1;
	} else {
		if (tty->termios->c_cflag & CLOCAL)
			do_clocal = 1;
	}
	
	/*
	 * Block waiting for the carrier detect and the line to become
	 * free (i.e., not in use by the callout).  While we are in
	 * this loop, state->count is dropped by one, so that
	 * rs_close() knows when to free things.  We restore it upon
	 * exit, either normal or abnormal.
	 */
	retval = 0;
	add_wait_queue(&info->open_wait, &wait);
#ifdef SERIAL_DEBUG_OPEN
	printk("block_til_ready before block: ttys%d, count = %d\n",
	       state->line, state->count);
#endif
	save_flags(flags); cli();
	if (!tty_hung_up_p(filp)) {
		extra_count = 1;
		state->count--;
	}
	restore_flags(flags);
	info->blocked_open++;
	while (1) {
		save_flags(flags); cli();
		if (!(info->flags & ASYNC_CALLOUT_ACTIVE) &&
		    (tty->termios->c_cflag & CBAUD))
			serial_out(info, UART_MCR,
				   serial_inp(info, UART_MCR) |
				   (UART_MCR_DTR | UART_MCR_RTS));
		restore_flags(flags);
		set_current_state(TASK_INTERRUPTIBLE);
		if (tty_hung_up_p(filp) ||
		    !(info->flags & ASYNC_INITIALIZED)) {
#ifdef SERIAL_DO_RESTART
			if (info->flags & ASYNC_HUP_NOTIFY)
				retval = -EAGAIN;
			else
				retval = -ERESTARTSYS;	
#else
			retval = -EAGAIN;
#endif
			break;
		}
		if (!(info->flags & ASYNC_CALLOUT_ACTIVE) &&
		    !(info->flags & ASYNC_CLOSING) &&
		    (do_clocal || (serial_in(info, UART_MSR) &
				   UART_MSR_DCD)))
			break;
		if (signal_pending(current)) {
			retval = -ERESTARTSYS;
			break;
		}
#ifdef SERIAL_DEBUG_OPEN
		printk("block_til_ready blocking: ttys%d, count = %d\n",
		       info->line, state->count);
#endif
		schedule();
	}
	set_current_state(TASK_RUNNING);
	remove_wait_queue(&info->open_wait, &wait);
	if (extra_count)
		state->count++;
	info->blocked_open--;
#ifdef SERIAL_DEBUG_OPEN
	printk("block_til_ready after blocking: ttys%d, count = %d\n",
	       info->line, state->count);
#endif
	if (retval)
		return retval;
	info->flags |= ASYNC_NORMAL_ACTIVE;
	return 0;
}

static int get_async_struct(int line, struct async_struct **ret_info)
{
	struct async_struct *info;
	struct serial_state *sstate;

	sstate = rs_table + line;
	sstate->count++;
	if (sstate->info) {
		*ret_info = sstate->info;
		return 0;
	}
	info = kmalloc(sizeof(struct async_struct), GFP_KERNEL);
	if (!info) {
		sstate->count--;
		return -ENOMEM;
	}
	memset(info, 0, sizeof(struct async_struct));
	init_waitqueue_head(&info->open_wait);
	init_waitqueue_head(&info->close_wait);
	init_waitqueue_head(&info->delta_msr_wait);
	info->magic = SERIAL_MAGIC;
	info->port = sstate->port;
	info->flags = sstate->flags;
	info->io_type = sstate->io_type;
	info->iomem_base = sstate->iomem_base;
	info->iomem_reg_shift = sstate->iomem_reg_shift;
	info->xmit_fifo_size = sstate->xmit_fifo_size;
	info->line = line;
	info->tqueue.routine = do_softint;
	info->tqueue.data = info;
	info->state = sstate;
	if (sstate->info) {
		kfree(info);
		*ret_info = sstate->info;
		return 0;
	}
	*ret_info = sstate->info = info;
	return 0;
}

/*
 * This routine is called whenever a serial port is opened.  It
 * enables interrupts for a serial port, linking in its async structure into
 * the IRQ chain.   It also performs the serial-specific
 * initialization for the tty structure.
 */
static int rs_open(struct tty_struct *tty, struct file * filp)
{
	struct async_struct	*info;
	int 			retval, line;
	unsigned long		page;

	MOD_INC_USE_COUNT;
	line = MINOR(tty->device) - tty->driver.minor_start;
	if ((line < 0) || (line >= NR_PORTS)) {
		MOD_DEC_USE_COUNT;
		return -ENODEV;
	}
	retval = get_async_struct(line, &info);
	if (retval) {
		MOD_DEC_USE_COUNT;
		return retval;
	}
	tty->driver_data = info;
	info->tty = tty;
	if (serial_paranoia_check(info, tty->device, "rs_open")) {
		MOD_DEC_USE_COUNT;		
		return -ENODEV;
	}

#ifdef SERIAL_DEBUG_OPEN
	printk("rs_open %s%d, count = %d\n", tty->driver.name, info->line,
	       info->state->count);
#endif
	info->tty->low_latency = (info->flags & ASYNC_LOW_LATENCY) ? 1 : 0;

	if (!tmp_buf) {
		page = get_zeroed_page(GFP_KERNEL);
		if (!page) {
			MOD_DEC_USE_COUNT;
			return -ENOMEM;
		}
		if (tmp_buf)
			free_page(page);
		else
			tmp_buf = (unsigned char *) page;
	}

	/*
	 * If the port is the middle of closing, bail out now
	 */
	if (tty_hung_up_p(filp) ||
	    (info->flags & ASYNC_CLOSING)) {
		if (info->flags & ASYNC_CLOSING)
			interruptible_sleep_on(&info->close_wait);
		MOD_DEC_USE_COUNT;
#ifdef SERIAL_DO_RESTART
		return ((info->flags & ASYNC_HUP_NOTIFY) ?
			-EAGAIN : -ERESTARTSYS);
#else
		return -EAGAIN;
#endif
	}

	/*
	 * Start up serial port
	 */
	retval = startup(info);
	if (retval) {
		MOD_DEC_USE_COUNT;
		return retval;
	}

	retval = block_til_ready(tty, filp, info);
	if (retval) {
#ifdef SERIAL_DEBUG_OPEN
		printk("rs_open returning after block_til_ready with %d\n",
		       retval);
#endif
		MOD_DEC_USE_COUNT;
		return retval;
	}

	if ((info->state->count == 1) &&
	    (info->flags & ASYNC_SPLIT_TERMIOS)) {
		if (tty->driver.subtype == SERIAL_TYPE_NORMAL)
			*tty->termios = info->state->normal_termios;
		else 
			*tty->termios = info->state->callout_termios;
		change_speed(info, 0);
	}
#ifdef CONFIG_AU1000_SERIAL_CONSOLE
	if (sercons.cflag && sercons.index == line) {
		tty->termios->c_cflag = sercons.cflag;
		sercons.cflag = 0;
		change_speed(info, 0);
	}
#endif
	info->session = current->session;
	info->pgrp = current->pgrp;

#ifdef SERIAL_DEBUG_OPEN
	printk("rs_open ttys%d successful...", info->line);
#endif
	return 0;
}

/*
 * /proc fs routines....
 */

static inline int line_info(char *buf, struct serial_state *state)
{
	struct async_struct *info = state->info, scr_info;
	char	stat_buf[30], control, status;
	int	ret;
	unsigned long flags;

	ret = sprintf(buf, "%d: uart:%s port:%lX irq:%d",
		      state->line, uart_config[state->type].name, 
		      state->port, state->irq);

	if (!state->port || (state->type == PORT_UNKNOWN)) {
		ret += sprintf(buf+ret, "\n");
		return ret;
	}

	/*
	 * Figure out the current RS-232 lines
	 */
	if (!info) {
		info = &scr_info;	/* This is just for serial_{in,out} */

		info->magic = SERIAL_MAGIC;
		info->port = state->port;
		info->flags = state->flags;
		info->quot = 0;
		info->tty = 0;
	}
	save_flags(flags); cli();
	status = serial_in(info, UART_MSR);
	control = info != &scr_info ? info->MCR : serial_in(info, UART_MCR);
	restore_flags(flags); 

	stat_buf[0] = 0;
	stat_buf[1] = 0;
	if (control & UART_MCR_RTS)
		strcat(stat_buf, "|RTS");
	if (status & UART_MSR_CTS)
		strcat(stat_buf, "|CTS");
	if (control & UART_MCR_DTR)
		strcat(stat_buf, "|DTR");
	if (status & UART_MSR_DSR)
		strcat(stat_buf, "|DSR");
	if (status & UART_MSR_DCD)
		strcat(stat_buf, "|CD");
	if (status & UART_MSR_RI)
		strcat(stat_buf, "|RI");

	if (info->quot) {
		ret += sprintf(buf+ret, " baud:%d",
			       state->baud_base / info->quot);
	}

	ret += sprintf(buf+ret, " tx:%d rx:%d",
		      state->icount.tx, state->icount.rx);

	if (state->icount.frame)
		ret += sprintf(buf+ret, " fe:%d", state->icount.frame);
	
	if (state->icount.parity)
		ret += sprintf(buf+ret, " pe:%d", state->icount.parity);
	
	if (state->icount.brk)
		ret += sprintf(buf+ret, " brk:%d", state->icount.brk);	

	if (state->icount.overrun)
		ret += sprintf(buf+ret, " oe:%d", state->icount.overrun);

	/*
	 * Last thing is the RS-232 status lines
	 */
	ret += sprintf(buf+ret, " %s\n", stat_buf+1);
	return ret;
}

int rs_read_proc(char *page, char **start, off_t off, int count,
		 int *eof, void *data)
{
	int i, len = 0, l;
	off_t	begin = 0;

	len += sprintf(page, "serinfo:1.0 driver:%s%s revision:%s\n",
		       serial_version, LOCAL_VERSTRING, serial_revdate);
	for (i = 0; i < NR_PORTS && len < 4000; i++) {
		l = line_info(page + len, &rs_table[i]);
		len += l;
		if (len+begin > off+count)
			goto done;
		if (len+begin < off) {
			begin += len;
			len = 0;
		}
	}
	*eof = 1;
done:
	if (off >= len+begin)
		return 0;
	*start = page + (off-begin);
	return ((count < beg