zs.c

自己根据lkd和情境分析

		tty->hw_stopped = 0;
		zs_start(tty);
	}
}

/*
 * ------------------------------------------------------------
 * zs_close()
 * 
 * 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
 * ZILOG structure from the interrupt chain if necessary, and we free
 * that IRQ if nothing is left in the chain.
 * ------------------------------------------------------------
 */
static void zs_close(struct tty_struct *tty, struct file * filp)
{
	struct sun_serial * info = (struct sun_serial *) tty->driver_data;
	unsigned long flags;

	if (!info || serial_paranoia_check(info, tty->device, "zs_close"))
		return;
	
	save_flags(flags); cli();
	
	if (tty_hung_up_p(filp)) {
		restore_flags(flags);
		return;
	}
	
#ifdef SERIAL_DEBUG_OPEN
	printk("zs_close tty-%d, count = %d\n", info->line, info->count);
#endif
	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("zs_close: bad serial port count; tty->count is 1, "
		       "info->count is %d\n", info->count);
		info->count = 1;
	}
	if (--info->count < 0) {
		printk("zs_close: bad serial port count for ttys%d: %d\n",
		       info->line, info->count);
		info->count = 0;
	}
	if (info->count) {
		restore_flags(flags);
		return;
	}
	info->flags |= ZILOG_CLOSING;
	/*
	 * Save the termios structure, since this port may have
	 * separate termios for callout and dialin.
	 */
	if (info->flags & ZILOG_NORMAL_ACTIVE)
		info->normal_termios = *tty->termios;
	if (info->flags & ZILOG_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 != ZILOG_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.
	 */
	/** if (!info->iscons) ... **/
	info->curregs[3] &= ~RxENAB;
	write_zsreg(info->zs_channel, 3, info->curregs[3]);
	info->curregs[1] &= ~(RxINT_MASK);
	write_zsreg(info->zs_channel, 1, info->curregs[1]);
	ZS_CLEARFIFO(info->zs_channel);

	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 (tty->ldisc.num != ldiscs[N_TTY].num) {
		if (tty->ldisc.close)
			(tty->ldisc.close)(tty);
		tty->ldisc = ldiscs[N_TTY];
		tty->termios->c_line = N_TTY;
		if (tty->ldisc.open)
			(tty->ldisc.open)(tty);
	}
	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 &= ~(ZILOG_NORMAL_ACTIVE|ZILOG_CALLOUT_ACTIVE|
			 ZILOG_CLOSING);
	wake_up_interruptible(&info->close_wait);
#ifdef SERIAL_DEBUG_OPEN
	printk("zs_close tty-%d exiting, count = %d\n", info->line, info->count);
#endif
	restore_flags(flags);
}

/*
 * zs_hangup() --- called by tty_hangup() when a hangup is signaled.
 */
void zs_hangup(struct tty_struct *tty)
{
	struct sun_serial * info = (struct sun_serial *) tty->driver_data;

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

	if (info->is_cons)
		return;

#ifdef SERIAL_DEBUG_OPEN
	printk("zs_hangup<%p: tty-%d, count = %d bye\n",
		__builtin_return_address(0), info->line, info->count);
#endif

	zs_flush_buffer(tty);
	shutdown(info);
	info->event = 0;
	info->count = 0;
	info->flags &= ~(ZILOG_NORMAL_ACTIVE|ZILOG_CALLOUT_ACTIVE);
	info->tty = 0;
	wake_up_interruptible(&info->open_wait);
}

/*
 *
 * line_info - returns information about each channel
 *
 */
static inline int line_info(char *buf, struct sun_serial *info)
{
	unsigned char status;
	char stat_buf[30];
	int ret;

	ret = sprintf(buf, "%d: uart:Zilog8530 port:%x irq:%d",
		info->line, info->port, info->irq);

	cli();
	status = sbus_readb(&info->zs_channel->control);
	ZSDELAY();
	ZSLOG(REGCTRL, status, 0);
	sti();

	stat_buf[0] = 0;
	stat_buf[1] = 0;
	if (info->curregs[5] & RTS)
		strcat(stat_buf, "|RTS");
	if (status & CTS)
		strcat(stat_buf, "|CTS");
	if (info->curregs[5] & DTR)
		strcat(stat_buf, "|DTR");
	if (status & SYNC)
		strcat(stat_buf, "|DSR");
	if (status & DCD)
		strcat(stat_buf, "|CD");

	ret += sprintf(buf + ret, " baud:%d %s\n", info->zs_baud, stat_buf + 1);
	return ret;
}

/*
 *
 * zs_read_proc() - called when /proc/tty/driver/serial is read.
 *
 */
int zs_read_proc(char *page, char **start, off_t off, int count,
                 int *eof, void *data)
{
	char *revision = "$Revision: 1.1.1.1 $";
	char *version, *p;
	int i, len = 0, l;
	off_t begin = 0;

	version = strchr(revision, ' ');
	p = strchr(++version, ' ');
	*p = '\0';
	len += sprintf(page, "serinfo:1.0 driver:%s\n", version);
	*p = ' ';

	for (i = 0; i < NUM_CHANNELS && len < 4000; i++) {
		l = line_info(page + len, &zs_soft[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 < begin+len-off) ? count : begin+len-off);
}

/*
 * ------------------------------------------------------------
 * zs_open() and friends
 * ------------------------------------------------------------
 */
static int block_til_ready(struct tty_struct *tty, struct file * filp,
			   struct sun_serial *info)
{
	DECLARE_WAITQUEUE(wait, current);
	int retval, do_clocal = 0;
	unsigned char r0;

	/*
	 * If the device is in the middle of being closed, then block
	 * until it's done, and then try again.
	 */
	if (info->flags & ZILOG_CLOSING) {
		interruptible_sleep_on(&info->close_wait);
#ifdef SERIAL_DO_RESTART
		if (info->flags & ZILOG_HUP_NOTIFY)
			return -EAGAIN;
		else
			return -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 & ZILOG_NORMAL_ACTIVE)
			return -EBUSY;
		if ((info->flags & ZILOG_CALLOUT_ACTIVE) &&
		    (info->flags & ZILOG_SESSION_LOCKOUT) &&
		    (info->session != current->session))
		    return -EBUSY;
		if ((info->flags & ZILOG_CALLOUT_ACTIVE) &&
		    (info->flags & ZILOG_PGRP_LOCKOUT) &&
		    (info->pgrp != current->pgrp))
		    return -EBUSY;
		info->flags |= ZILOG_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 & ZILOG_CALLOUT_ACTIVE)
			return -EBUSY;
		info->flags |= ZILOG_NORMAL_ACTIVE;
		return 0;
	}

	if (info->flags & ZILOG_CALLOUT_ACTIVE) {
		if (info->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, info->count is dropped by one, so that
	 * zs_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",
	       info->line, info->count);
#endif
	cli();
	if(!tty_hung_up_p(filp))
		info->count--;
	sti();
	info->blocked_open++;
	while (1) {
		cli();
		if (!(info->flags & ZILOG_CALLOUT_ACTIVE))
			zs_rtsdtr(info, 1);
		sti();
		set_current_state(TASK_INTERRUPTIBLE);
		if (tty_hung_up_p(filp) ||
		    !(info->flags & ZILOG_INITIALIZED)) {
#ifdef SERIAL_DEBUG_OPEN
			printk("block_til_ready hup-ed: ttys%d, count = %d\n",
				info->line, info->count);
#endif
#ifdef SERIAL_DO_RESTART
			if (info->flags & ZILOG_HUP_NOTIFY)
				retval = -EAGAIN;
			else
				retval = -ERESTARTSYS;	
#else
			retval = -EAGAIN;
#endif
			break;
		}

		cli();
		r0 = read_zsreg(info->zs_channel, R0);
		sti();
		if (!(info->flags & ZILOG_CALLOUT_ACTIVE) &&
		    !(info->flags & ZILOG_CLOSING) &&
		    (do_clocal || (DCD & r0)))
			break;
		if (signal_pending(current)) {
			retval = -ERESTARTSYS;
			break;
		}
#ifdef SERIAL_DEBUG_OPEN
		printk("block_til_ready blocking: ttys%d, count = %d\n",
		       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 SERIAL_DEBUG_OPEN
	printk("block_til_ready after blocking: ttys%d, count = %d\n",
	       info->line, info->count);
#endif
	if (retval)
		return retval;
	info->flags |= ZILOG_NORMAL_ACTIVE;
	return 0;
}	

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

	line = MINOR(tty->device) - tty->driver.minor_start;

	/* The zilog lines for the mouse/keyboard must be
	 * opened using their respective drivers.
	 */
	if ((line < 0) || (line >= NUM_CHANNELS))
		return -ENODEV;
	if((line == KEYBOARD_LINE) || (line == MOUSE_LINE))
		return -ENODEV;
	info = zs_soft + line;
	/* Is the kgdb running over this line? */
	if (info->kgdb_channel)
		return -ENODEV;
	if (serial_paranoia_check(info, tty->device, "zs_open"))
		return -ENODEV;
#ifdef SERIAL_DEBUG_OPEN
	printk("zs_open %s%d, count = %d\n", tty->driver.name, info->line,
	       info->count);
#endif
	if (info->tty != 0 && info->tty != tty) {
		/* Never happen? */
		printk("zs_open %s%d, tty overwrite.\n", tty->driver.name, info->line);
		return -EBUSY;
	}

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

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

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

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

	if ((info->count == 1) && (info->flags & ZILOG_SPLIT_TERMIOS)) {
		if (tty->driver.subtype == SERIAL_TYPE_NORMAL)
			*tty->termios = info->normal_termios;
		else 
			*tty->termios = info->callout_termios;
		change_speed(info);
	}

#ifdef CONFIG_SERIAL_CONSOLE
	if (zs_console.cflag && zs_console.index == line) {
		tty->termios->c_cflag = zs_console.cflag;
		zs_console.cflag = 0;
		change_speed(info);
	}
#endif

	info->session = current->session;
	info->pgrp = current->pgrp;

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

/* Finally, routines used to initialize the serial driver. */

static void show_serial_version(void)
{
	char *revision = "$Revision: 1.1.1.1 $";
	char *version, *p;

	version = strchr(revision, ' ');
	p = strchr(++version, ' ');
	*p = '\0';
	printk("Sparc Zilog8530 serial driver version %s\n", version);
	*p = ' ';
}

/* Probe the PROM for the request zs chip number.
 *
 * Note: The Sun Voyager shows two addresses and two intr for it's
 *       Zilogs, what the second does, I don't know. It does work
 *       with using only the first number of each property.  Also
 *       we have a special version for sun4u.
 */
#ifdef __sparc_v9__
static struct sun_zslayout * __init get_zs(int chip)
{
	unsigned int vaddr[2] = { 0, 0 };
	unsigned long mapped_addr = 0;
	int busnode, seen, zsnode, sun4u_ino;
	static int irq = 0;

	if(chip < 0 || chip >= NUM_SERIAL) {
		prom_printf("get_zs bogon zs chip number");
		prom_halt();
	}

	if(central_bus)
		busnode = central_bus->child->prom_node;
	else
		busnode = prom_searchsiblings(prom_getchild(prom_root_node), "sbus");
	if(busnode == 0 || busnode == -1) {
		prom_printf("get_zs: no zs bus to search");
		prom_halt();
	}
	zsnode = prom_getchild(busnode);
	seen = 0;
	while(zsnode) {
		int slave;

		zsnode = prom_searchsiblings(zsnode, "zs");
		slave = prom_getintdefault(zsnode, "slave", -1);
		if((slave == chip) || (seen == chip)) {
			int len = prom_getproperty(zsnode, "address",
						   (void *) vaddr, sizeof(vaddr));

			if(len == -1 || central_bus != NULL) {
				struct sbus_bus *sbus = NULL;
				struct sbus_dev *sdev = NULL;

				/* "address" property is not guarenteed,