epca.c

来自「linux 内核源代码」· C语言 代码 · 共 2,328 行 · 第 1/5 页

		spin_lock_irqsave(&epca_lock, flags);
		tty->closing = 0;
		ch->event = 0;
		ch->tty = NULL;
		spin_unlock_irqrestore(&epca_lock, flags);

		if (ch->blocked_open) {
			if (ch->close_delay)
				msleep_interruptible(jiffies_to_msecs(ch->close_delay));
			wake_up_interruptible(&ch->open_wait);
		}
		ch->asyncflags &= ~(ASYNC_NORMAL_ACTIVE | ASYNC_INITIALIZED |
		                      ASYNC_CLOSING);
		wake_up_interruptible(&ch->close_wait);
	}
}

static void shutdown(struct channel *ch)
{
	unsigned long flags;
	struct tty_struct *tty;
	struct board_chan __iomem *bc;

	if (!(ch->asyncflags & ASYNC_INITIALIZED))
		return;

	spin_lock_irqsave(&epca_lock, flags);

	globalwinon(ch);
	bc = ch->brdchan;

	/*
	 * In order for an event to be generated on the receipt of data the
	 * idata flag must be set. Since we are shutting down, this is not
	 * necessary clear this flag.
	 */
	if (bc)
		writeb(0, &bc->idata);
	tty = ch->tty;

	/* If we're a modem control device and HUPCL is on, drop RTS & DTR. */
	if (tty->termios->c_cflag & HUPCL)  {
		ch->omodem &= ~(ch->m_rts | ch->m_dtr);
		fepcmd(ch, SETMODEM, 0, ch->m_dtr | ch->m_rts, 10, 1);
	}
	memoff(ch);

	/*
	 * The channel has officialy been closed. The next time it is opened it
	 * will have to reinitialized. Set a flag to indicate this.
	 */
	/* Prevent future Digi programmed interrupts from coming active */
	ch->asyncflags &= ~ASYNC_INITIALIZED;
	spin_unlock_irqrestore(&epca_lock, flags);
}

static void pc_hangup(struct tty_struct *tty)
{
	struct channel *ch;

	/*
	 * verifyChannel returns the channel from the tty struct if it is
	 * valid. This serves as a sanity check.
	 */
	if ((ch = verifyChannel(tty)) != NULL) {
		unsigned long flags;

		if (tty->driver->flush_buffer)
			tty->driver->flush_buffer(tty);
		tty_ldisc_flush(tty);
		shutdown(ch);

		spin_lock_irqsave(&epca_lock, flags);
		ch->tty   = NULL;
		ch->event = 0;
		ch->count = 0;
		ch->asyncflags &= ~(ASYNC_NORMAL_ACTIVE | ASYNC_INITIALIZED);
		spin_unlock_irqrestore(&epca_lock, flags);
		wake_up_interruptible(&ch->open_wait);
	}
}

static int pc_write(struct tty_struct *tty,
                    const unsigned char *buf, int bytesAvailable)
{
	unsigned int head, tail;
	int dataLen;
	int size;
	int amountCopied;
	struct channel *ch;
	unsigned long flags;
	int remain;
	struct board_chan __iomem *bc;

	/*
	 * pc_write is primarily called directly by the kernel routine
	 * tty_write (Though it can also be called by put_char) found in
	 * tty_io.c. pc_write is passed a line discipline buffer where the data
	 * to be written out is stored. The line discipline implementation
	 * itself is done at the kernel level and is not brought into the
	 * driver.
	 */

	/*
	 * verifyChannel returns the channel from the tty struct if it is
	 * valid. This serves as a sanity check.
	 */
	if ((ch = verifyChannel(tty)) == NULL)
		return 0;

	/* Make a pointer to the channel data structure found on the board. */
	bc   = ch->brdchan;
	size = ch->txbufsize;
	amountCopied = 0;

	spin_lock_irqsave(&epca_lock, flags);
	globalwinon(ch);

	head = readw(&bc->tin) & (size - 1);
	tail = readw(&bc->tout);

	if (tail != readw(&bc->tout))
		tail = readw(&bc->tout);
	tail &= (size - 1);

	if (head >= tail) {
		/* head has not wrapped */
		/*
		 * remain (much like dataLen above) represents the total amount
		 * of space available on the card for data. Here dataLen
		 * represents the space existing between the head pointer and
		 * the end of buffer. This is important because a memcpy cannot
		 * be told to automatically wrap around when it hits the buffer
		 * end.
		 */
		dataLen = size - head;
		remain = size - (head - tail) - 1;
	} else {
		/* head has wrapped around */
		remain = tail - head - 1;
		dataLen = remain;
	}
	/*
	 * Check the space on the card. If we have more data than space; reduce
	 * the amount of data to fit the space.
	 */
	bytesAvailable = min(remain, bytesAvailable);
	txwinon(ch);
	while (bytesAvailable > 0) {
		/* there is data to copy onto card */

		/*
		 * If head is not wrapped, the below will make sure the first
		 * data copy fills to the end of card buffer.
		 */
		dataLen = min(bytesAvailable, dataLen);
		memcpy_toio(ch->txptr + head, buf, dataLen);
		buf += dataLen;
		head += dataLen;
		amountCopied += dataLen;
		bytesAvailable -= dataLen;

		if (head >= size) {
			head = 0;
			dataLen = tail;
		}
	}
	ch->statusflags |= TXBUSY;
	globalwinon(ch);
	writew(head, &bc->tin);

	if ((ch->statusflags & LOWWAIT) == 0)  {
		ch->statusflags |= LOWWAIT;
		writeb(1, &bc->ilow);
	}
	memoff(ch);
	spin_unlock_irqrestore(&epca_lock, flags);
	return amountCopied;
}

static void pc_put_char(struct tty_struct *tty, unsigned char c)
{
	pc_write(tty, &c, 1);
}

static int pc_write_room(struct tty_struct *tty)
{
	int remain;
	struct channel *ch;
	unsigned long flags;
	unsigned int head, tail;
	struct board_chan __iomem *bc;

	remain = 0;

	/*
	 * verifyChannel returns the channel from the tty struct if it is
	 * valid. This serves as a sanity check.
	 */
	if ((ch = verifyChannel(tty)) != NULL)  {
		spin_lock_irqsave(&epca_lock, flags);
		globalwinon(ch);

		bc   = ch->brdchan;
		head = readw(&bc->tin) & (ch->txbufsize - 1);
		tail = readw(&bc->tout);

		if (tail != readw(&bc->tout))
			tail = readw(&bc->tout);
		/* Wrap tail if necessary */
		tail &= (ch->txbufsize - 1);

		if ((remain = tail - head - 1) < 0 )
			remain += ch->txbufsize;

		if (remain && (ch->statusflags & LOWWAIT) == 0) {
			ch->statusflags |= LOWWAIT;
			writeb(1, &bc->ilow);
		}
		memoff(ch);
		spin_unlock_irqrestore(&epca_lock, flags);
	}
	/* Return how much room is left on card */
	return remain;
}

static int pc_chars_in_buffer(struct tty_struct *tty)
{
	int chars;
	unsigned int ctail, head, tail;
	int remain;
	unsigned long flags;
	struct channel *ch;
	struct board_chan __iomem *bc;

	/*
	 * verifyChannel returns the channel from the tty struct if it is
	 * valid. This serves as a sanity check.
	 */
	if ((ch = verifyChannel(tty)) == NULL)
		return 0;

	spin_lock_irqsave(&epca_lock, flags);
	globalwinon(ch);

	bc = ch->brdchan;
	tail = readw(&bc->tout);
	head = readw(&bc->tin);
	ctail = readw(&ch->mailbox->cout);

	if (tail == head && readw(&ch->mailbox->cin) == ctail && readb(&bc->tbusy) == 0)
		chars = 0;
	else  { /* Begin if some space on the card has been used */
		head = readw(&bc->tin) & (ch->txbufsize - 1);
		tail &= (ch->txbufsize - 1);
		/*
		 * The logic here is basically opposite of the above
		 * pc_write_room here we are finding the amount of bytes in the
		 * buffer filled. Not the amount of bytes empty.
		 */
		if ((remain = tail - head - 1) < 0 )
			remain += ch->txbufsize;
		chars = (int)(ch->txbufsize - remain);
		/*
		 * Make it possible to wakeup anything waiting for output in
		 * tty_ioctl.c, etc.
		 *
		 * If not already set. Setup an event to indicate when the
		 * transmit buffer empties.
		 */
		if (!(ch->statusflags & EMPTYWAIT))
			setup_empty_event(tty,ch);
	} /* End if some space on the card has been used */
	memoff(ch);
	spin_unlock_irqrestore(&epca_lock, flags);
	/* Return number of characters residing on card. */
	return chars;
}

static void pc_flush_buffer(struct tty_struct *tty)
{
	unsigned int tail;
	unsigned long flags;
	struct channel *ch;
	struct board_chan __iomem *bc;
	/*
	 * verifyChannel returns the channel from the tty struct if it is
	 * valid. This serves as a sanity check.
	 */
	if ((ch = verifyChannel(tty)) == NULL)
		return;

	spin_lock_irqsave(&epca_lock, flags);
	globalwinon(ch);
	bc   = ch->brdchan;
	tail = readw(&bc->tout);
	/* Have FEP move tout pointer; effectively flushing transmit buffer */
	fepcmd(ch, STOUT, (unsigned) tail, 0, 0, 0);
	memoff(ch);
	spin_unlock_irqrestore(&epca_lock, flags);
	tty_wakeup(tty);
}

static void pc_flush_chars(struct tty_struct *tty)
{
	struct channel *ch;
	/*
	 * verifyChannel returns the channel from the tty struct if it is
	 * valid. This serves as a sanity check.
	 */
	if ((ch = verifyChannel(tty)) != NULL) {
		unsigned long flags;
		spin_lock_irqsave(&epca_lock, flags);
		/*
		 * If not already set and the transmitter is busy setup an
		 * event to indicate when the transmit empties.
		 */
		if ((ch->statusflags & TXBUSY) && !(ch->statusflags & EMPTYWAIT))
			setup_empty_event(tty,ch);
		spin_unlock_irqrestore(&epca_lock, flags);
	}
}

static int block_til_ready(struct tty_struct *tty,
                           struct file *filp, struct channel *ch)
{
	DECLARE_WAITQUEUE(wait,current);
	int retval, do_clocal = 0;
	unsigned long flags;

	if (tty_hung_up_p(filp)) {
		if (ch->asyncflags & ASYNC_HUP_NOTIFY)
			retval = -EAGAIN;
		else
			retval = -ERESTARTSYS;
		return retval;
	}

	/*
	 * If the device is in the middle of being closed, then block until
	 * it's done, and then try again.
	 */
	if (ch->asyncflags & ASYNC_CLOSING) {
		interruptible_sleep_on(&ch->close_wait);

		if (ch->asyncflags & ASYNC_HUP_NOTIFY)
			return -EAGAIN;
		else
			return -ERESTARTSYS;
	}

	if (filp->f_flags & O_NONBLOCK)  {
		/*
		 * If non-blocking mode is set, then make the check up front
		 * and then exit.
		 */
		ch->asyncflags |= 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 */

	retval = 0;
	add_wait_queue(&ch->open_wait, &wait);

	spin_lock_irqsave(&epca_lock, flags);
	/* We dec count so that pc_close will know when to free things */
	if (!tty_hung_up_p(filp))
		ch->count--;
	ch->blocked_open++;
	while (1) {
		set_current_state(TASK_INTERRUPTIBLE);
		if (tty_hung_up_p(filp) ||
		    !(ch->asyncflags & ASYNC_INITIALIZED))
		{
			if (ch->asyncflags & ASYNC_HUP_NOTIFY)
				retval = -EAGAIN;
			else
				retval = -ERESTARTSYS;
			break;
		}
		if (!(ch->asyncflags & ASYNC_CLOSING) &&
			  (do_clocal || (ch->imodem & ch->dcd)))
			break;
		if (signal_pending(current)) {
			retval = -ERESTARTSYS;
			break;
		}
		spin_unlock_irqrestore(&epca_lock, flags);
		/*
		 * Allow someone else to be scheduled. We will occasionally go
		 * through this loop until one of the above conditions change.
		 * The below schedule call will allow other processes to enter
		 * and prevent this loop from hogging the cpu.
		 */
		schedule();
		spin_lock_irqsave(&epca_lock, flags);
	}

	__set_current_state(TASK_RUNNING);
	remove_wait_queue(&ch->open_wait, &wait);
	if (!tty_hung_up_p(filp))
		ch->count++;
	ch->blocked_open--;

	spin_unlock_irqrestore(&epca_lock, flags);

	if (retval)
		return retval;

	ch->asyncflags |= ASYNC_NORMAL_ACTIVE;
	return 0;
}

static int pc_open(struct tty_struct *tty, struct file * filp)
{
	struct channel *ch;
	unsigned long flags;
	int line, retval, boardnum;
	struct board_chan __iomem *bc;
	unsigned int head;

	line = tty->index;
	if (line < 0 || line >= nbdevs)
		return -ENODEV;

	ch = &digi_channels[line];
	boardnum = ch->boardnum;

	/* Check status of board configured in system.  */

	/*
	 * I check to see if the epca_setup routine detected an user error. It
	 * might be better to put this in pc_init, but for the moment it goes
	 * here.
	 */
	if (invalid_lilo_config) {
		if (setup_error_code & INVALID_BOARD_TYPE)
			printk(KERN_ERR "epca: pc_open: Invalid board type specified in kernel options.\n");
		if (setup_error_code & INVALID_NUM_PORTS)
			printk(KERN_ERR "epca: pc_open: Invalid number of ports specified in kernel options.\n");
		if (setup_error_code & INVALID_MEM_BASE)
			printk(KERN_ERR "epca: pc_open: Invalid board memory address specified in kernel options.\n");
		if (setup_error_code & INVALID_PORT_BASE)
			printk(KERN_ERR "epca; pc_open: Invalid board port address specified in kernel options.\n");
		if (setup_error_code & INVALID_BOARD_STATUS)
			printk(KERN_ERR "epca: pc_open: Invalid board status specified in kernel options.\n");
		if (setup_error_code & INVALID_ALTPIN)
			printk(KERN_ERR "epca: pc_open: Invalid board altpin specified in kernel options;\n");
		tty->driver_data = NULL;   /* Mark this device as 'down' */
		return -ENODEV;
	}
	if (boardnum >= num_cards || boards[boardnum].status == DISABLED)  {
		tty->driver_data = NULL;   /* Mark this device as 'down' */
		return(-ENODEV);
	}

	if ((bc = ch->brdchan) == 0) {
		tty->driver_data = NULL;
		return -ENODEV;
	}

	spin_lock_irqsave(&epca_lock, flags);
	/*