ctctty.c

内核linux2.4.20,可跟rtlinux3.2打补丁 组成实时linux系统,编译内核

ctc_tty_block_til_ready(struct tty_struct *tty, struct file *filp, ctc_tty_info *info)
{
	DECLARE_WAITQUEUE(wait, NULL);
	int do_clocal = 0;
	unsigned long flags;
	int retval;

	/*
	 * 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 & CTC_ASYNC_CLOSING)) {
		if (info->flags & CTC_ASYNC_CLOSING)
			interruptible_sleep_on(&info->close_wait);
#ifdef MODEM_DO_RESTART
		if (info->flags & CTC_ASYNC_HUP_NOTIFY)
			return -EAGAIN;
		else
			return -ERESTARTSYS;
#else
		return -EAGAIN;
#endif
	}
	/*
	 * If non-blocking mode is set, then make the check up front
	 * and then exit.
	 */
	if ((filp->f_flags & O_NONBLOCK) ||
	    (tty->flags & (1 << TTY_IO_ERROR))) {
		info->flags |= CTC_ASYNC_NORMAL_ACTIVE;
		return 0;
	}
	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, info->count is dropped by one, so that
	 * ctc_tty_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 CTC_DEBUG_MODEM_OPEN
	printk(KERN_DEBUG "ctc_tty_block_til_ready before block: %s%d, count = %d\n",
	       CTC_TTY_NAME, info->line, info->count);
#endif
	save_flags(flags);
	cli();
	if (!(tty_hung_up_p(filp)))
		info->count--;
	restore_flags(flags);
	info->blocked_open++;
	while (1) {
		set_current_state(TASK_INTERRUPTIBLE);
		if (tty_hung_up_p(filp) ||
		    !(info->flags & CTC_ASYNC_INITIALIZED)) {
#ifdef MODEM_DO_RESTART
			if (info->flags & CTC_ASYNC_HUP_NOTIFY)
				retval = -EAGAIN;
			else
				retval = -ERESTARTSYS;
#else
			retval = -EAGAIN;
#endif
			break;
		}
		if (!(info->flags & CTC_ASYNC_CLOSING) &&
		    (do_clocal || (info->msr & UART_MSR_DCD))) {
			break;
		}
		if (signal_pending(current)) {
			retval = -ERESTARTSYS;
			break;
		}
#ifdef CTC_DEBUG_MODEM_OPEN
		printk(KERN_DEBUG "ctc_tty_block_til_ready blocking: %s%d, count = %d\n",
		       CTC_TTY_NAME, info->line, info->count);
#endif
		schedule();
	}
	current->state = TASK_RUNNING;
	remove_wait_queue(&info->open_wait, &wait);
	if (!tty_hung_up_p(filp))
		info->count++;
	info->blocked_open--;
#ifdef CTC_DEBUG_MODEM_OPEN
	printk(KERN_DEBUG "ctc_tty_block_til_ready after blocking: %s%d, count = %d\n",
	       CTC_TTY_NAME, info->line, info->count);
#endif
	if (retval)
		return retval;
	info->flags |= CTC_ASYNC_NORMAL_ACTIVE;
	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
ctc_tty_open(struct tty_struct *tty, struct file *filp)
{
	ctc_tty_info *info;
	unsigned long saveflags;
	int retval,
	 line;

	line = MINOR(tty->device) - tty->driver.minor_start;
	if (line < 0 || line > CTC_TTY_MAX_DEVICES)
		return -ENODEV;
	info = &driver->info[line];
	if (ctc_tty_paranoia_check(info, tty->device, "ctc_tty_open"))
		return -ENODEV;
	if (!info->netdev)
		return -ENODEV;
#ifdef CTC_DEBUG_MODEM_OPEN
	printk(KERN_DEBUG "ctc_tty_open %s%d, count = %d\n", tty->driver.name,
	       info->line, info->count);
#endif
	spin_lock_irqsave(&ctc_tty_lock, saveflags);
	info->count++;
	tty->driver_data = info;
	info->tty = tty;
	spin_unlock_irqrestore(&ctc_tty_lock, saveflags);
	/*
	 * Start up serial port
	 */
	retval = ctc_tty_startup(info);
	if (retval) {
#ifdef CTC_DEBUG_MODEM_OPEN
		printk(KERN_DEBUG "ctc_tty_open return after startup\n");
#endif
		return retval;
	}
	retval = ctc_tty_block_til_ready(tty, filp, info);
	if (retval) {
#ifdef CTC_DEBUG_MODEM_OPEN
		printk(KERN_DEBUG "ctc_tty_open return after ctc_tty_block_til_ready \n");
#endif
		return retval;
	}
	if ((info->count == 1) && (info->flags & CTC_ASYNC_SPLIT_TERMIOS)) {
		*tty->termios = info->normal_termios;
		ctc_tty_change_speed(info);
	}
#ifdef CTC_DEBUG_MODEM_OPEN
	printk(KERN_DEBUG "ctc_tty_open %s%d successful...\n", CTC_TTY_NAME, info->line);
#endif
	return 0;
}

static void
ctc_tty_close(struct tty_struct *tty, struct file *filp)
{
	ctc_tty_info *info = (ctc_tty_info *) tty->driver_data;
	unsigned long saveflags;
	ulong flags;
	ulong timeout;

	if (!info || ctc_tty_paranoia_check(info, tty->device, "ctc_tty_close"))
		return;
	save_flags(flags);
	cli();
	if (tty_hung_up_p(filp)) {
		restore_flags(flags);
#ifdef CTC_DEBUG_MODEM_OPEN
		printk(KERN_DEBUG "ctc_tty_close return after tty_hung_up_p\n");
#endif
		return;
	}
	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(KERN_ERR "ctc_tty_close: bad port count; tty->count is 1, "
		       "info->count is %d\n", info->count);
		info->count = 1;
	}
	if (--info->count < 0) {
		printk(KERN_ERR "ctc_tty_close: bad port count for %s%d: %d\n",
		       CTC_TTY_NAME, info->line, info->count);
		info->count = 0;
	}
	if (info->count) {
		restore_flags(flags);
#ifdef CTC_DEBUG_MODEM_OPEN
		printk(KERN_DEBUG "ctc_tty_close after info->count != 0\n");
#endif
		return;
	}
	info->flags |= CTC_ASYNC_CLOSING;
	/*
	 * Save the termios structure, since this port may have
	 * separate termios for callout and dialin.
	 */
	if (info->flags & CTC_ASYNC_NORMAL_ACTIVE)
		info->normal_termios = *tty->termios;

	tty->closing = 1;
	/*
	 * 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.
	 */
	if (info->flags & CTC_ASYNC_INITIALIZED) {
		tty_wait_until_sent(tty, 3000);	/* 30 seconds timeout */
		/*
		 * Before we drop DTR, make sure the UART transmitter
		 * has completely drained; this is especially
		 * important if there is a transmit FIFO!
		 */
		timeout = jiffies + HZ;
		while (!(info->lsr & UART_LSR_TEMT)) {
			set_current_state(TASK_INTERRUPTIBLE);
			schedule_timeout(20);
			if (time_after(jiffies,timeout))
				break;
		}
	}
	ctc_tty_shutdown(info);
	if (tty->driver.flush_buffer)
		tty->driver.flush_buffer(tty);
	if (tty->ldisc.flush_buffer)
		tty->ldisc.flush_buffer(tty);
	spin_lock_irqsave(&ctc_tty_lock, saveflags);
	info->tty = 0;
	spin_unlock_irqrestore(&ctc_tty_lock, saveflags);
	tty->closing = 0;
	if (info->blocked_open) {
		set_current_state(TASK_INTERRUPTIBLE);
		schedule_timeout(50);
		wake_up_interruptible(&info->open_wait);
	}
	info->flags &= ~(CTC_ASYNC_NORMAL_ACTIVE | CTC_ASYNC_CLOSING);
	wake_up_interruptible(&info->close_wait);
	restore_flags(flags);
#ifdef CTC_DEBUG_MODEM_OPEN
	printk(KERN_DEBUG "ctc_tty_close normal exit\n");
#endif
}

/*
 * ctc_tty_hangup() --- called by tty_hangup() when a hangup is signaled.
 */
static void
ctc_tty_hangup(struct tty_struct *tty)
{
	ctc_tty_info *info = (ctc_tty_info *)tty->driver_data;
	unsigned long saveflags;

	if (ctc_tty_paranoia_check(info, tty->device, "ctc_tty_hangup"))
		return;
	ctc_tty_shutdown(info);
	info->count = 0;
	info->flags &= ~CTC_ASYNC_NORMAL_ACTIVE;
	spin_lock_irqsave(&ctc_tty_lock, saveflags);
	info->tty = 0;
	spin_unlock_irqrestore(&ctc_tty_lock, saveflags);
	wake_up_interruptible(&info->open_wait);
}


/*
 * For all online tty's, try sending data to
 * the lower levels.
 */
static void
ctc_tty_task(ctc_tty_info *info)
{
	unsigned long saveflags;
	int again;

	spin_lock_irqsave(&ctc_tty_lock, saveflags);
	if ((!ctc_tty_shuttingdown) && info) {
		again = ctc_tty_tint(info);
		if (!again)
			info->lsr |= UART_LSR_TEMT;
		again |= ctc_tty_readmodem(info);
		if (again) {
			queue_task(&info->tq, &tq_immediate);
			mark_bh(IMMEDIATE_BH);
		}
	}
	spin_unlock_irqrestore(&ctc_tty_lock, saveflags);
}

int
ctc_tty_init(void)
{
	int i;
	ctc_tty_info *info;
	struct tty_driver *device;

	driver = kmalloc(sizeof(ctc_tty_driver), GFP_KERNEL);
	if (driver == NULL) {
		printk(KERN_WARNING "Out of memory in ctc_tty_modem_init\n");
		return -ENOMEM;
	}
	memset(driver, 0, sizeof(ctc_tty_driver));
	device = &driver->ctc_tty_device;

	device->magic = TTY_DRIVER_MAGIC;
	device->name = ctc_ttyname;
	device->major = CTC_TTY_MAJOR;
	device->minor_start = 0;
	device->num = CTC_TTY_MAX_DEVICES;
	device->type = TTY_DRIVER_TYPE_SERIAL;
	device->subtype = CTC_SERIAL_TYPE_NORMAL;
	device->init_termios = tty_std_termios;
	device->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
	device->flags = TTY_DRIVER_REAL_RAW;
	device->refcount = &driver->refcount;
	device->table = driver->modem_table;
	device->termios = driver->modem_termios;
	device->termios_locked = driver->modem_termios_locked;
	device->open = ctc_tty_open;
	device->close = ctc_tty_close;
	device->write = ctc_tty_write;
	device->put_char = NULL;
	device->flush_chars = ctc_tty_flush_chars;
	device->write_room = ctc_tty_write_room;
	device->chars_in_buffer = ctc_tty_chars_in_buffer;
	device->flush_buffer = ctc_tty_flush_buffer;
	device->ioctl = ctc_tty_ioctl;
	device->throttle = ctc_tty_throttle;
	device->unthrottle = ctc_tty_unthrottle;
	device->set_termios = ctc_tty_set_termios;
	device->stop = NULL;
	device->start = NULL;
	device->hangup = ctc_tty_hangup;
	device->driver_name = "ctc_tty";

	if (tty_register_driver(device)) {
		printk(KERN_WARNING "ctc_tty: Couldn't register serial-device\n");
		kfree(driver);
		return -1;
	}
	for (i = 0; i < CTC_TTY_MAX_DEVICES; i++) {
		info = &driver->info[i];
		init_MUTEX(&info->write_sem);
#if LINUX_VERSION_CODE >= 0x020400
		INIT_LIST_HEAD(&info->tq.list);
#else
		info->tq.next    = NULL;
#endif
		info->tq.sync    = 0;
		info->tq.routine = (void *)(void *)ctc_tty_task;
		info->tq.data    = info;
		info->magic = CTC_ASYNC_MAGIC;
		info->line = i;
		info->tty = 0;
		info->count = 0;
		info->blocked_open = 0;
		info->normal_termios = device->init_termios;
		init_waitqueue_head(&info->open_wait);
		init_waitqueue_head(&info->close_wait);
		skb_queue_head_init(&info->tx_queue);
		skb_queue_head_init(&info->rx_queue);
		init_timer(&info->stoptimer);
		info->stoptimer.function = ctc_tty_stopdev;
		info->stoptimer.data = (unsigned long)info;
		info->mcr = UART_MCR_RTS;
	}
	return 0;
}

int
ctc_tty_register_netdev(net_device *dev) {
	int ttynum;
	char *err;
	char *p;

	if ((!dev) || (!dev->name)) {
		printk(KERN_WARNING
		       "ctc_tty_register_netdev called "
		       "with NULL dev or NULL dev-name\n");
		return -1;
	}
	for (p = dev->name; p && ((*p < '0') || (*p > '9')); p++);
	ttynum = simple_strtoul(p, &err, 0);
	if ((ttynum < 0) || (ttynum >= CTC_TTY_MAX_DEVICES) ||
	    (err && *err)) {
		printk(KERN_WARNING
		       "ctc_tty_register_netdev called "
		       "with number in name '%s'\n", dev->name);
		return -1;
	}
	if (driver->info[ttynum].netdev) {
		printk(KERN_WARNING
		       "ctc_tty_register_netdev called "
		       "for already registered device '%s'\n",
		       dev->name);
		return -1;
	}
	driver->info[ttynum].netdev = dev;
	return 0;
}

void
ctc_tty_unregister_netdev(net_device *dev) {
	int i;
	unsigned long saveflags;
	ctc_tty_info *info = NULL;

	spin_lock_irqsave(&ctc_tty_lock, saveflags);
	for (i = 0; i < CTC_TTY_MAX_DEVICES; i++)
		if (driver->info[i].netdev == dev) {
			info = &driver->info[i];
			break;
		}
	if (info) {
		info->netdev = NULL;
		skb_queue_purge(&info->tx_queue);
		skb_queue_purge(&info->rx_queue);
	}
	spin_unlock_irqrestore(&ctc_tty_lock, saveflags);
}

void
ctc_tty_cleanup(int final) {
	unsigned long saveflags;
	
	spin_lock_irqsave(&ctc_tty_lock, saveflags);
	ctc_tty_shuttingdown = 1;
	if (final) {
		kfree(driver);
		driver = NULL;
	} else {
		int i;

		for (i = 0; i < CTC_TTY_MAX_DEVICES; i++)
			driver->info[i].tq.routine = NULL;
		tty_unregister_driver(&driver->ctc_tty_device);
	}
	spin_unlock_irqrestore(&ctc_tty_lock, saveflags);
}