istallion.c

讲述linux的初始化过程

	sp = str;
	if ((*sp == '0') && (*(sp+1) == 'x')) {
		base = 16;
		sp += 2;
	} else if (*sp == '0') {
		base = 8;
		sp++;
	} else {
		base = 10;
	}

	for (; (*sp != 0); sp++) {
		c = (*sp > '9') ? (TOLOWER(*sp) - 'a' + 10) : (*sp - '0');
		if ((c < 0) || (c >= base)) {
			printk("STALLION: invalid argument %s\n", str);
			val = 0;
			break;
		}
		val = (val * base) + c;
	}
	return(val);
}

/*****************************************************************************/

/*
 *	Parse the supplied argument string, into the board conf struct.
 */

static int stli_parsebrd(stlconf_t *confp, char **argp)
{
	char	*sp;
	int	nrbrdnames, i;

#if DEBUG
	printk("stli_parsebrd(confp=%x,argp=%x)\n", (int) confp, (int) argp);
#endif

	if ((argp[0] == (char *) NULL) || (*argp[0] == 0))
		return(0);

	for (sp = argp[0], i = 0; ((*sp != 0) && (i < 25)); sp++, i++)
		*sp = TOLOWER(*sp);

	nrbrdnames = sizeof(stli_brdstr) / sizeof(stlibrdtype_t);
	for (i = 0; (i < nrbrdnames); i++) {
		if (strcmp(stli_brdstr[i].name, argp[0]) == 0)
			break;
	}
	if (i >= nrbrdnames) {
		printk("STALLION: unknown board name, %s?\n", argp[0]);
		return(0);
	}

	confp->brdtype = stli_brdstr[i].type;
	if ((argp[1] != (char *) NULL) && (*argp[1] != 0))
		confp->ioaddr1 = stli_atol(argp[1]);
	if ((argp[2] != (char *) NULL) && (*argp[2] != 0))
		confp->memaddr = stli_atol(argp[2]);
	return(1);
}

#endif

/*****************************************************************************/

/*
 *	Local driver kernel malloc routine.
 */

static void *stli_memalloc(int len)
{
	return((void *) kmalloc(len, GFP_KERNEL));
}

/*****************************************************************************/

static int stli_open(struct tty_struct *tty, struct file *filp)
{
	stlibrd_t	*brdp;
	stliport_t	*portp;
	unsigned int	minordev;
	int		brdnr, portnr, rc;

#if DEBUG
	printk("stli_open(tty=%x,filp=%x): device=%x\n", (int) tty,
		(int) filp, tty->device);
#endif

	minordev = MINOR(tty->device);
	brdnr = MINOR2BRD(minordev);
	if (brdnr >= stli_nrbrds)
		return(-ENODEV);
	brdp = stli_brds[brdnr];
	if (brdp == (stlibrd_t *) NULL)
		return(-ENODEV);
	if ((brdp->state & BST_STARTED) == 0)
		return(-ENODEV);
	portnr = MINOR2PORT(minordev);
	if ((portnr < 0) || (portnr > brdp->nrports))
		return(-ENODEV);

	portp = brdp->ports[portnr];
	if (portp == (stliport_t *) NULL)
		return(-ENODEV);
	if (portp->devnr < 1)
		return(-ENODEV);

	MOD_INC_USE_COUNT;

/*
 *	Check if this port is in the middle of closing. If so then wait
 *	until it is closed then return error status based on flag settings.
 *	The sleep here does not need interrupt protection since the wakeup
 *	for it is done with the same context.
 */
	if (portp->flags & ASYNC_CLOSING) {
		interruptible_sleep_on(&portp->close_wait);
		if (portp->flags & ASYNC_HUP_NOTIFY)
			return(-EAGAIN);
		return(-ERESTARTSYS);
	}

/*
 *	On the first open of the device setup the port hardware, and
 *	initialize the per port data structure. Since initializing the port
 *	requires several commands to the board we will need to wait for any
 *	other open that is already initializing the port.
 */
	portp->tty = tty;
	tty->driver_data = portp;
	portp->refcount++;

	while (test_bit(ST_INITIALIZING, &portp->state)) {
		if (signal_pending(current))
			return(-ERESTARTSYS);
		interruptible_sleep_on(&portp->raw_wait);
	}

	if ((portp->flags & ASYNC_INITIALIZED) == 0) {
		set_bit(ST_INITIALIZING, &portp->state);
		if ((rc = stli_initopen(brdp, portp)) >= 0) {
			portp->flags |= ASYNC_INITIALIZED;
			clear_bit(TTY_IO_ERROR, &tty->flags);
		}
		clear_bit(ST_INITIALIZING, &portp->state);
		wake_up_interruptible(&portp->raw_wait);
		if (rc < 0)
			return(rc);
	}

/*
 *	Check if this port is in the middle of closing. If so then wait
 *	until it is closed then return error status, based on flag settings.
 *	The sleep here does not need interrupt protection since the wakeup
 *	for it is done with the same context.
 */
	if (portp->flags & ASYNC_CLOSING) {
		interruptible_sleep_on(&portp->close_wait);
		if (portp->flags & ASYNC_HUP_NOTIFY)
			return(-EAGAIN);
		return(-ERESTARTSYS);
	}

/*
 *	Based on type of open being done check if it can overlap with any
 *	previous opens still in effect. If we are a normal serial device
 *	then also we might have to wait for carrier.
 */
	if (tty->driver.subtype == STL_DRVTYPCALLOUT) {
		if (portp->flags & ASYNC_NORMAL_ACTIVE)
			return(-EBUSY);
		if (portp->flags & ASYNC_CALLOUT_ACTIVE) {
			if ((portp->flags & ASYNC_SESSION_LOCKOUT) &&
			    (portp->session != current->session))
				return(-EBUSY);
			if ((portp->flags & ASYNC_PGRP_LOCKOUT) &&
			    (portp->pgrp != current->pgrp))
				return(-EBUSY);
		}
		portp->flags |= ASYNC_CALLOUT_ACTIVE;
	} else {
		if (filp->f_flags & O_NONBLOCK) {
			if (portp->flags & ASYNC_CALLOUT_ACTIVE)
				return(-EBUSY);
		} else {
			if ((rc = stli_waitcarrier(brdp, portp, filp)) != 0)
				return(rc);
		}
		portp->flags |= ASYNC_NORMAL_ACTIVE;
	}

	if ((portp->refcount == 1) && (portp->flags & ASYNC_SPLIT_TERMIOS)) {
		if (tty->driver.subtype == STL_DRVTYPSERIAL)
			*tty->termios = portp->normaltermios;
		else
			*tty->termios = portp->callouttermios;
		stli_setport(portp);
	}

	portp->session = current->session;
	portp->pgrp = current->pgrp;
	return(0);
}

/*****************************************************************************/

static void stli_close(struct tty_struct *tty, struct file *filp)
{
	stlibrd_t	*brdp;
	stliport_t	*portp;
	unsigned long	flags;

#if DEBUG
	printk("stli_close(tty=%x,filp=%x)\n", (int) tty, (int) filp);
#endif

	portp = tty->driver_data;
	if (portp == (stliport_t *) NULL)
		return;

	save_flags(flags);
	cli();
	if (tty_hung_up_p(filp)) {
		MOD_DEC_USE_COUNT;
		restore_flags(flags);
		return;
	}
	if ((tty->count == 1) && (portp->refcount != 1))
		portp->refcount = 1;
	if (portp->refcount-- > 1) {
		MOD_DEC_USE_COUNT;
		restore_flags(flags);
		return;
	}

	portp->flags |= ASYNC_CLOSING;

	if (portp->flags & ASYNC_NORMAL_ACTIVE)
		portp->normaltermios = *tty->termios;
	if (portp->flags & ASYNC_CALLOUT_ACTIVE)
		portp->callouttermios = *tty->termios;

/*
 *	May want to wait for data to drain before closing. The BUSY flag
 *	keeps track of whether we are still transmitting or not. It is
 *	updated by messages from the slave - indicating when all chars
 *	really have drained.
 */
	if (tty == stli_txcooktty)
		stli_flushchars(tty);
	tty->closing = 1;
	if (portp->closing_wait != ASYNC_CLOSING_WAIT_NONE)
		tty_wait_until_sent(tty, portp->closing_wait);

	portp->flags &= ~ASYNC_INITIALIZED;
	brdp = stli_brds[portp->brdnr];
	stli_rawclose(brdp, portp, 0, 0);
	if (tty->termios->c_cflag & HUPCL) {
		stli_mkasysigs(&portp->asig, 0, 0);
		if (test_bit(ST_CMDING, &portp->state))
			set_bit(ST_DOSIGS, &portp->state);
		else
			stli_sendcmd(brdp, portp, A_SETSIGNALS, &portp->asig,
				sizeof(asysigs_t), 0);
	}
	clear_bit(ST_TXBUSY, &portp->state);
	clear_bit(ST_RXSTOP, &portp->state);
	set_bit(TTY_IO_ERROR, &tty->flags);
	if (tty->ldisc.flush_buffer)
		(tty->ldisc.flush_buffer)(tty);
	set_bit(ST_DOFLUSHRX, &portp->state);
	stli_flushbuffer(tty);

	tty->closing = 0;
	portp->tty = (struct tty_struct *) NULL;

	if (portp->openwaitcnt) {
		if (portp->close_delay)
			stli_delay(portp->close_delay);
		wake_up_interruptible(&portp->open_wait);
	}

	portp->flags &= ~(ASYNC_CALLOUT_ACTIVE | ASYNC_NORMAL_ACTIVE |
		ASYNC_CLOSING);
	wake_up_interruptible(&portp->close_wait);
	MOD_DEC_USE_COUNT;
	restore_flags(flags);
}

/*****************************************************************************/

/*
 *	Carry out first open operations on a port. This involves a number of
 *	commands to be sent to the slave. We need to open the port, set the
 *	notification events, set the initial port settings, get and set the
 *	initial signal values. We sleep and wait in between each one. But
 *	this still all happens pretty quickly.
 */

static int stli_initopen(stlibrd_t *brdp, stliport_t *portp)
{
	struct tty_struct	*tty;
	asynotify_t		nt;
	asyport_t		aport;
	int			rc;

#if DEBUG
	printk("stli_initopen(brdp=%x,portp=%x)\n", (int) brdp, (int) portp);
#endif

	if ((rc = stli_rawopen(brdp, portp, 0, 1)) < 0)
		return(rc);

	memset(&nt, 0, sizeof(asynotify_t));
	nt.data = (DT_TXLOW | DT_TXEMPTY | DT_RXBUSY | DT_RXBREAK);
	nt.signal = SG_DCD;
	if ((rc = stli_cmdwait(brdp, portp, A_SETNOTIFY, &nt,
	    sizeof(asynotify_t), 0)) < 0)
		return(rc);

	tty = portp->tty;
	if (tty == (struct tty_struct *) NULL)
		return(-ENODEV);
	stli_mkasyport(portp, &aport, tty->termios);
	if ((rc = stli_cmdwait(brdp, portp, A_SETPORT, &aport,
	    sizeof(asyport_t), 0)) < 0)
		return(rc);

	set_bit(ST_GETSIGS, &portp->state);
	if ((rc = stli_cmdwait(brdp, portp, A_GETSIGNALS, &portp->asig,
	    sizeof(asysigs_t), 1)) < 0)
		return(rc);
	if (test_and_clear_bit(ST_GETSIGS, &portp->state))
		portp->sigs = stli_mktiocm(portp->asig.sigvalue);
	stli_mkasysigs(&portp->asig, 1, 1);
	if ((rc = stli_cmdwait(brdp, portp, A_SETSIGNALS, &portp->asig,
	    sizeof(asysigs_t), 0)) < 0)
		return(rc);

	return(0);
}

/*****************************************************************************/

/*
 *	Send an open message to the slave. This will sleep waiting for the
 *	acknowledgement, so must have user context. We need to co-ordinate
 *	with close events here, since we don't want open and close events
 *	to overlap.
 */

static int stli_rawopen(stlibrd_t *brdp, stliport_t *portp, unsigned long arg, int wait)
{
	volatile cdkhdr_t	*hdrp;
	volatile cdkctrl_t	*cp;
	volatile unsigned char	*bits;
	unsigned long		flags;
	int			rc;

#if DEBUG
	printk("stli_rawopen(brdp=%x,portp=%x,arg=%x,wait=%d)\n",
		(int) brdp, (int) portp, (int) arg, wait);
#endif

/*
 *	Send a message to the slave to open this port.
 */
	save_flags(flags);
	cli();

/*
 *	Slave is already closing this port. This can happen if a hangup
 *	occurs on this port. So we must wait until it is complete. The
 *	order of opens and closes may not be preserved across shared
 *	memory, so we must wait until it is complete.
 */
	while (test_bit(ST_CLOSING, &portp->state)) {
		if (signal_pending(current)) {
			restore_flags(flags);
			return(-ERESTARTSYS);
		}
		interruptible_sleep_on(&portp->raw_wait);
	}

/*
 *	Everything is ready now, so write the open message into shared
 *	memory. Once the message is in set the service bits to say that
 *	this port wants service.
 */
	EBRDENABLE(brdp);
	cp = &((volatile cdkasy_t *) EBRDGETMEMPTR(brdp, portp->addr))->ctrl;
	cp->openarg = arg;
	cp->open = 1;
	hdrp = (volatile cdkhdr_t *) EBRDGETMEMPTR(brdp, CDK_CDKADDR);
	bits = ((volatile unsigned char *) hdrp) + brdp->slaveoffset +
		portp->portidx;
	*bits |= portp->portbit;
	EBRDDISABLE(brdp);

	if (wait == 0) {
		restore_flags(flags);
		return(0);
	}

/*
 *	Slave is in action, so now we must wait for the open acknowledgment
 *	to come back.
 */
	rc = 0;
	set_bit(ST_OPENING, &portp->state);
	while (test_bit(ST_OPENING, &portp->state)) {
		if (signal_pending(current)) {
			rc = -ERESTARTSYS;
			break;
		}
		interruptible_sleep_on(&portp->raw_wait);
	}
	restore_flags(flags);

	if ((rc == 0) && (portp->rc != 0))
		rc = -EIO;
	return(rc);
}

/*****************************************************************************/

/*
 *	Send a close message to the slave. Normally this will sleep waiting
 *	for the acknowledgement, but if wait parameter is 0 it will not. If
 *	wait is true then must have user context (to sleep).
 */

static int stli_rawclose(stlibrd_t *brdp, stliport_t *portp, unsigned long arg, int wait)
{
	volatile cdkhdr_t	*hdrp;
	volatile cdkctrl_t	*cp;
	volatile unsigned char	*bits;
	unsigned long		flags;
	int			rc;

#if DEBUG
	printk("stli_rawclose(brdp=%x,portp=%x,arg=%x,wait=%d)\n",
		(int) brdp, (int) portp, (int) arg, wait);
#endif

	save_flags(flags);
	cli();

/*
 *	Slave is already closing this port. This can happen if a hangup
 *	occurs on this port.
 */
	if (wait) {
		while (test_bit(ST_CLOSING, &portp->state)) {
			if (signal_pending(current)) {
				restore_flags(flags);
				return(-ERESTARTSYS);
			}
			interruptible_sleep_on(&portp->raw_wait);
		}
	}

/*
 *	Write the close command into shared memory.
 */
	EBRDENABLE(brdp);
	cp = &((volatile cdkasy_t *) EBRDGETMEMPTR(brdp, portp->addr))->ctrl;
	cp->closearg = arg;
	cp->close = 1;
	hdrp = (volatile cdkhdr_t *) EBRDGETMEMPTR(brdp, CDK_CDKADDR);