vsta

/*
 * Per async port state
 */
static struct asy {
	char *a_tty;		/* Port accessed */
	port_t a_txport,	/* Open ports to this name */
		a_rxport;

	char *a_txbuf;		/* When active, buffer being sent */
	int a_txcnt;		/*  ...size */
	char *a_rxbuf;		/* Receive buffer */

	int a_hd, a_tl;		/* Head/tail of rx FIFO */
	pid_t a_txpid,		/* Thread serving this port (tx) */
		a_rxpid;	/*   ...rx */
} asy[ASY_MAX];

/*
 * ioinit()
 *	Called at startup time to set up console I/O
................................................................................
 * asy_rx_daemon()
 *	Thread to watch for incoming bytes, and queue them
 */
static void
asy_rx_daemon(struct asy *ap)
{
	struct msg m;
	int cnt;

	for (;;) {
		/*
		 * See how much we can pull in this time
		 */

		if (ap->a_hd >= ap->a_tl) {
			cnt = BUFLEN - ap->a_hd;
		} else {
			cnt = (ap->a_tl - ap->a_hd);
		}
		if (cnt <= 1) {
			__msleep(10);
			continue;
		}
		cnt -= 1;

		/*
		 * Do the receive
		 */
		m.m_op = FS_READ | M_READ;
		m.m_arg = m.m_buflen = cnt;
		m.m_arg1 = 0;
................................................................................

		/*
		 * Transmit it
		 */
		m.m_op = FS_WRITE;
		m.m_arg = m.m_buflen = ap->a_txcnt;
		m.m_arg1 = 0;
		m.m_buf = ap->a_txbuf;
		m.m_nseg = 1;
		(void)msg_send(ap->a_txport, &m);

		/*
		 * Flag completion
		 */
		ap->a_txbuf = 0;
................................................................................
	/* 
	 * Set to default parameters
	 */
	(void)wstat(p, "baud=9600\n");
	(void)wstat(p, "databits=8\n");
	(void)wstat(p, "stopbits=1\n");
	(void)wstat(p, "parity=none\n");


	/*
	 * Initialize tty, launch threads
	 */
	ap->a_txport = clone(p);
	ap->a_rxbuf = malloc(BUFLEN);
	ap->a_rxpid = tfork(asy_rx_daemon, (ulong)ap);
................................................................................
 *
 * Returns count of characters read
 */
int16
asy_recv(int16 dev, char *buf, int cnt)
{
	struct asy *ap = &asy[dev];
	int avail;

	/*
	 * Take the lesser of how much is there and how much
	 * they want.
	 */

	if (ap->a_hd < ap->a_tl) {
		avail = BUFLEN - ap->a_tl;
	} else {
		avail = ap->a_hd - ap->a_tl;
	}
	if (avail > cnt) {
		avail = cnt;
	}
	if (avail <= 0) {
		return(0);
	}
................................................................................
	 * Copy it out
	 */
	bcopy(ap->a_rxbuf + ap->a_tl, buf, avail);

	/*
	 * Update state
	 */
	ap->a_tl += avail;
	if (ap->a_tl >= BUFLEN) {
		ap->a_tl = 0;


	}

	return(avail);
}

/*
 * asy_ioctl()

/*
 * Per async port state
 */
static struct asy {
	char *a_tty;		/* Port accessed */
	port_t a_txport,	/* Open ports to this name */
		a_rxport;
	char volatile *
		a_txbuf;	/* When active, buffer being sent */
	int a_txcnt;		/*  ...size */
	char *a_rxbuf;		/* Receive buffer */
	volatile int
		a_hd, a_tl;	/* Head/tail of rx FIFO */
	pid_t a_txpid,		/* Thread serving this port (tx) */
		a_rxpid;	/*   ...rx */
} asy[ASY_MAX];

/*
 * ioinit()
 *	Called at startup time to set up console I/O
................................................................................
 * asy_rx_daemon()
 *	Thread to watch for incoming bytes, and queue them
 */
static void
asy_rx_daemon(struct asy *ap)
{
	struct msg m;
	int cnt, tl;

	for (;;) {
		/*
		 * See how much we can pull in this time
		 */
		tl = ap->a_tl;
		if (ap->a_hd >= tl) {
			cnt = BUFLEN - ap->a_hd;
		} else {
			cnt = (tl - ap->a_hd) - 1;
		}
		if (cnt <= 0) {
			__msleep(10);
			continue;
		}


		/*
		 * Do the receive
		 */
		m.m_op = FS_READ | M_READ;
		m.m_arg = m.m_buflen = cnt;
		m.m_arg1 = 0;
................................................................................

		/*
		 * Transmit it
		 */
		m.m_op = FS_WRITE;
		m.m_arg = m.m_buflen = ap->a_txcnt;
		m.m_arg1 = 0;
		m.m_buf = (char *)ap->a_txbuf;
		m.m_nseg = 1;
		(void)msg_send(ap->a_txport, &m);

		/*
		 * Flag completion
		 */
		ap->a_txbuf = 0;
................................................................................
	/* 
	 * Set to default parameters
	 */
	(void)wstat(p, "baud=9600\n");
	(void)wstat(p, "databits=8\n");
	(void)wstat(p, "stopbits=1\n");
	(void)wstat(p, "parity=none\n");
	(void)wstat(p, "onlcr=0\n");

	/*
	 * Initialize tty, launch threads
	 */
	ap->a_txport = clone(p);
	ap->a_rxbuf = malloc(BUFLEN);
	ap->a_rxpid = tfork(asy_rx_daemon, (ulong)ap);
................................................................................
 *
 * Returns count of characters read
 */
int16
asy_recv(int16 dev, char *buf, int cnt)
{
	struct asy *ap = &asy[dev];
	int x, avail;

	/*
	 * Take the lesser of how much is there and how much
	 * they want.
	 */
	x = ap->a_hd;
	if (x < ap->a_tl) {
		avail = BUFLEN - ap->a_tl;
	} else {
		avail = x - ap->a_tl;
	}
	if (avail > cnt) {
		avail = cnt;
	}
	if (avail <= 0) {
		return(0);
	}
................................................................................
	 * Copy it out
	 */
	bcopy(ap->a_rxbuf + ap->a_tl, buf, avail);

	/*
	 * Update state
	 */
	x = ap->a_tl + avail;
	if (x >= BUFLEN) {
		ap->a_tl = 0;
	} else {
		ap->a_tl = x;
	}

	return(avail);
}

/*
 * asy_ioctl()