mxser.c

讲述linux的初始化过程

	memset(&mxvar_sdriver, 0, sizeof(struct tty_driver));
	mxvar_sdriver.magic = TTY_DRIVER_MAGIC;
	mxvar_sdriver.name = "ttyM";
	mxvar_sdriver.major = ttymajor;
	mxvar_sdriver.minor_start = 0;
	mxvar_sdriver.num = MXSER_PORTS + 1;
	mxvar_sdriver.type = TTY_DRIVER_TYPE_SERIAL;
	mxvar_sdriver.subtype = SERIAL_TYPE_NORMAL;
	mxvar_sdriver.init_termios = tty_std_termios;
	mxvar_sdriver.init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
	mxvar_sdriver.flags = TTY_DRIVER_REAL_RAW;
	mxvar_sdriver.refcount = &mxvar_refcount;
	mxvar_sdriver.table = mxvar_tty;
	mxvar_sdriver.termios = mxvar_termios;
	mxvar_sdriver.termios_locked = mxvar_termios_locked;

	mxvar_sdriver.open = mxser_open;
	mxvar_sdriver.close = mxser_close;
	mxvar_sdriver.write = mxser_write;
	mxvar_sdriver.put_char = mxser_put_char;
	mxvar_sdriver.flush_chars = mxser_flush_chars;
	mxvar_sdriver.write_room = mxser_write_room;
	mxvar_sdriver.chars_in_buffer = mxser_chars_in_buffer;
	mxvar_sdriver.flush_buffer = mxser_flush_buffer;
	mxvar_sdriver.ioctl = mxser_ioctl;
	mxvar_sdriver.throttle = mxser_throttle;
	mxvar_sdriver.unthrottle = mxser_unthrottle;
	mxvar_sdriver.set_termios = mxser_set_termios;
	mxvar_sdriver.stop = mxser_stop;
	mxvar_sdriver.start = mxser_start;
	mxvar_sdriver.hangup = mxser_hangup;

	/*
	 * The callout device is just like normal device except for
	 * major number and the subtype code.
	 */
	mxvar_cdriver = mxvar_sdriver;
	mxvar_cdriver.name = "cum";
	mxvar_cdriver.major = calloutmajor;
	mxvar_cdriver.subtype = SERIAL_TYPE_CALLOUT;

	printk("Tty devices major number = %d, callout devices major number = %d\n", ttymajor, calloutmajor);

	mxvar_diagflag = 0;
	memset(mxvar_table, 0, MXSER_PORTS * sizeof(struct mxser_struct));
	memset(&mxvar_log, 0, sizeof(struct mxser_log));


	m = 0;
	/* Start finding ISA boards here */
	for (b = 0; b < MXSER_BOARDS && m < MXSER_BOARDS; b++) {
		int cap;
		if (!(cap = mxserBoardCAP[b]))
			continue;

		retval = mxser_get_ISA_conf(cap, &hwconf);

		if (retval != 0)
			printk("Found MOXA %s board (CAP=0x%x)\n",
			       mxser_brdname[hwconf.board_type - 1],
			       ioaddr[b]);

		if (retval <= 0) {
			if (retval == MXSER_ERR_IRQ)
				printk("Invalid interrupt number,board not configured\n");
			else if (retval == MXSER_ERR_IRQ_CONFLIT)
				printk("Invalid interrupt number,board not configured\n");
			else if (retval == MXSER_ERR_VECTOR)
				printk("Invalid interrupt vector,board not configured\n");
			else if (retval == MXSER_ERR_IOADDR)
				printk("Invalid I/O address,board not configured\n");

			continue;
		}
		hwconf.pdev = NULL;

		if (mxser_initbrd(m, &hwconf) < 0)
			continue;

		mxser_getcfg(m, &hwconf);

		m++;
	}

	/* Start finding ISA boards from module arg */
	for (b = 0; b < MXSER_BOARDS && m < MXSER_BOARDS; b++) {
		int cap;
		if (!(cap = ioaddr[b]))
			continue;

		retval = mxser_get_ISA_conf(cap, &hwconf);

		if (retval != 0)
			printk("Found MOXA %s board (CAP=0x%x)\n",
			       mxser_brdname[hwconf.board_type - 1],
			       ioaddr[b]);

		if (retval <= 0) {
			if (retval == MXSER_ERR_IRQ)
				printk("Invalid interrupt number,board not configured\n");
			else if (retval == MXSER_ERR_IRQ_CONFLIT)
				printk("Invalid interrupt number,board not configured\n");
			else if (retval == MXSER_ERR_VECTOR)
				printk("Invalid interrupt vector,board not configured\n");
			else if (retval == MXSER_ERR_IOADDR)
				printk("Invalid I/O address,board not configured\n");

			continue;
		}
		hwconf.pdev = NULL;

		if (mxser_initbrd(m, &hwconf) < 0)
			continue;

		mxser_getcfg(m, &hwconf);

		m++;
	}

	/* start finding PCI board here */

#ifdef CONFIG_PCI
	{
		struct pci_dev *pdev = NULL;

		n = sizeof(mxser_pcibrds) / sizeof(mxser_pciinfo);
		index = 0;
		b = 0;
		while (b < n) {
			pdev = pci_find_device(mxser_pcibrds[b].vendor_id,
					       mxser_pcibrds[b].device_id, pdev);
			if (!pdev)
				break;
			if (pci_enable_device(pdev))
				continue;
			b++;
			hwconf.pdev = pdev;
			printk("Found MOXA %s board(BusNo=%d,DevNo=%d)\n",
				mxser_brdname[mxser_pcibrds[b].board_type - 1],
				pdev->bus->number, PCI_SLOT(pdev->devfn >> 3));
			if (m >= MXSER_BOARDS) {
				printk("Too many Smartio family boards find (maximum %d),board not configured\n", MXSER_BOARDS);
			} else {
				retval = mxser_get_PCI_conf(pdev,
				   mxser_pcibrds[b].board_type, &hwconf);
				if (retval < 0) {
					if (retval == MXSER_ERR_IRQ)
						printk("Invalid interrupt number,board not configured\n");
					else if (retval == MXSER_ERR_IRQ_CONFLIT)
						printk("Invalid interrupt number,board not configured\n");
					else if (retval == MXSER_ERR_VECTOR)
						printk("Invalid interrupt vector,board not configured\n");
					else if (retval == MXSER_ERR_IOADDR)
						printk("Invalid I/O address,board not configured\n");
					continue;

				}
				if (mxser_initbrd(m, &hwconf) < 0)
					continue;
				mxser_getcfg(m, &hwconf);
				m++;

			}

		}
	}
#endif

	for (i = m; i < MXSER_BOARDS; i++) {
		mxsercfg[i].board_type = -1;
	}


	ret1 = 0;
	ret2 = 0;
	if (!(ret1 = tty_register_driver(&mxvar_sdriver))) {
		if (!(ret2 = tty_register_driver(&mxvar_cdriver))) {
			return 0;
		} else {
			tty_unregister_driver(&mxvar_sdriver);
			printk("Couldn't install MOXA Smartio family callout driver !\n");
		}
	} else
		printk("Couldn't install MOXA Smartio family driver !\n");


	if (ret1 || ret2) {
		for (i = 0; i < MXSER_BOARDS; i++) {
			if (mxsercfg[i].board_type == -1)
				continue;
			else {
				free_irq(mxsercfg[i].irq, &mxvar_table[i * MXSER_PORTS_PER_BOARD]);
			}
		}
		return -1;
	}
	return (0);
}

static void mxser_do_softint(void *private_)
{
	struct mxser_struct *info = (struct mxser_struct *) private_;
	struct tty_struct *tty;

	tty = info->tty;
	if (tty) {
		if (test_and_clear_bit(MXSER_EVENT_TXLOW, &info->event)) {
			if ((tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) &&
			    tty->ldisc.write_wakeup)
				(tty->ldisc.write_wakeup) (tty);
			wake_up_interruptible(&tty->write_wait);
		}
		if (test_and_clear_bit(MXSER_EVENT_HANGUP, &info->event)) {
			tty_hangup(tty);	/* FIXME: module removal race here - AKPM */
		}
	}
	MOD_DEC_USE_COUNT;
}

/*
 * 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 mxser_open(struct tty_struct *tty, struct file *filp)
{
	struct mxser_struct *info;
	int retval, line;
	unsigned long page;

	line = PORTNO(tty);
	if (line == MXSER_PORTS)
		return (0);
	if ((line < 0) || (line > MXSER_PORTS))
		return (-ENODEV);
	info = mxvar_table + line;
	if (!info->base)
		return (-ENODEV);

	info->count++;
	tty->driver_data = info;
	info->tty = tty;

	if (!mxvar_tmp_buf) {
		page = get_free_page(GFP_KERNEL);
		if (!page)
			return (-ENOMEM);
		if (mxvar_tmp_buf)
			free_page(page);
		else
			mxvar_tmp_buf = (unsigned char *) page;
	}
	/*
	 * Start up serial port
	 */
	retval = mxser_startup(info);
	if (retval)
		return (retval);

	retval = mxser_block_til_ready(tty, filp, info);
	if (retval)
		return (retval);

	if ((info->count == 1) && (info->flags & ASYNC_SPLIT_TERMIOS)) {
		if (tty->driver.subtype == SERIAL_TYPE_NORMAL)
			*tty->termios = info->normal_termios;
		else
			*tty->termios = info->callout_termios;
		mxser_change_speed(info, 0);
	}
	info->session = current->session;
	info->pgrp = current->pgrp;

	MOD_INC_USE_COUNT;

	return (0);
}

/*
 * This routine is called when the serial port gets closed.  First, we
 * wait for the last remaining data to be sent.  Then, we unlink its
 * async structure from the interrupt chain if necessary, and we free
 * that IRQ if nothing is left in the chain.
 */

static void mxser_close(struct tty_struct *tty, struct file *filp)
{
	struct mxser_struct *info = (struct mxser_struct *) tty->driver_data;
	unsigned long flags;
	unsigned long timeout;

	if (PORTNO(tty) == MXSER_PORTS)
		return;
	if (!info)
		return;

	save_flags(flags);
	cli();

	if (tty_hung_up_p(filp)) {
		restore_flags(flags);
		MOD_DEC_USE_COUNT;
		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("mxser_close: bad serial port count; tty->count is 1, "
		       "info->count is %d\n", info->count);
		info->count = 1;
	}
	if (--info->count < 0) {
		printk("mxser_close: bad serial port count for ttys%d: %d\n",
		       info->port, info->count);
		info->count = 0;
	}
	if (info->count) {
		restore_flags(flags);
		MOD_DEC_USE_COUNT;
		return;
	}
	info->flags |= ASYNC_CLOSING;
	/*
	 * Save the termios structure, since this port may have
	 * separate termios for callout and dialin.
	 */
	if (info->flags & ASYNC_NORMAL_ACTIVE)
		info->normal_termios = *tty->termios;
	if (info->flags & ASYNC_CALLOUT_ACTIVE)
		info->callout_termios = *tty->termios;
	/*
	 * Now we wait for the transmit buffer to clear; and we notify
	 * the line discipline to only process XON/XOFF characters.
	 */
	tty->closing = 1;
	if (info->closing_wait != ASYNC_CLOSING_WAIT_NONE)
		tty_wait_until_sent(tty, info->closing_wait);
	/*
	 * 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.
	 */
	info->IER &= ~UART_IER_RLSI;
	/* by William
	   info->read_status_mask &= ~UART_LSR_DR;
	 */
	if (info->flags & ASYNC_INITIALIZED) {
		outb(info->IER, info->base + UART_IER);
		/*
		 * 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 (!(inb(info->base + UART_LSR) & UART_LSR_TEMT)) {
			current->state = TASK_INTERRUPTIBLE;
			schedule_timeout(5);
			if (jiffies > timeout)
				break;
		}
	}
	mxser_shutdown(info);
	if (tty->driver.flush_buffer)
		tty->driver.flush_buffer(tty);
	if (tty->ldisc.flush_buffer)
		tty->ldisc.flush_buffer(tty);
	tty->closing = 0;
	info->event = 0;
	info->tty = 0;
	if (info->blocked_open) {
		if (info->close_delay) {
			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);
	restore_flags(flags);

	MOD_DEC_USE_COUNT;
}

static int mxser_write(struct tty_struct *tty, int from_user,
		       const unsigned char *buf, int count)
{
	int c, total = 0;
	struct mxser_struct *info = (struct mxser_struct *) tty->driver_data;
	unsigned long flags;

	if (!tty || !info->xmit_buf || !mxvar_tmp_buf)
		return (0);

	if (from_user)
		down(&mxvar_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) {
			copy_from_user(mxvar_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, mxvar_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(&mxvar_tmp_buf_sem);
	if (info->xmit_cnt && !tty->stopped && !tty->hw_stopped &&
	    !(info->IER & UART_IER_THRI)) {
		info->IER |= UART_IER_THRI;
		outb(info->IER, info->base + UART_IER);
	}
	restore_flags(flags);
	return (total);
}

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

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

	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++;
	/********************************************** why ??? ***********
	if ( !tty->stopped && !tty->hw_stopped &&
	     !(info->IER & UART_IER_THRI) ) {
	    info->IER |= UART_IER_THRI;
	    outb(info->IER, info->base + UART_IER);
	}
	*****************************************************************/
	restore_flags(flags);
}

static void mxser_flush_chars(struct tty_struct *tty)
{
	struct mxser_struct *info = (struct mxser_struct *) tty->driver_data;
	unsigned long flags;

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

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

static int mxser_write_room(struct tty_struct *tty)
{
	struct mxser_struct *info = (struct mxser_struct *) tty->driver_data;
	int ret;

	ret = SERIAL_XMIT_SIZE - info->xmit_cnt - 1;
	if (ret < 0)