1 files changed, 317 insertions, 0 deletions
diff --git a/contrib/ntp/kernel/tty_clk.c b/contrib/ntp/kernel/tty_clk.c
new file mode 100644
index 0000000..0720610
--- /dev/null
+++ b/contrib/ntp/kernel/tty_clk.c
@@ -0,0 +1,317 @@
+/* tty_clk.c,v 3.1 1993/07/06 01:07:33 jbj Exp
+ * tty_clk.c - Generic line driver for receiving radio clock timecodes
+ */
+
+#include "clk.h"
+#if NCLK > 0
+
+#include "../h/param.h"
+#include "../h/types.h"
+#include "../h/systm.h"
+#include "../h/dir.h"
+#include "../h/user.h"
+#include "../h/ioctl.h"
+#include "../h/tty.h"
+#include "../h/proc.h"
+#include "../h/file.h"
+#include "../h/conf.h"
+#include "../h/buf.h"
+#include "../h/uio.h"
+#include "../h/clist.h"
+
+/*
+ * This line discipline is intended to provide well performing
+ * generic support for the reception and time stamping of radio clock
+ * timecodes.  Most radio clock devices return a string where a
+ * particular character in the code (usually a \r) is on-time
+ * synchronized with the clock.  The idea here is to collect characters
+ * until (one of) the synchronization character(s) (we allow two) is seen.
+ * When the magic character arrives we take a timestamp by calling
+ * microtime() and insert the eight bytes of struct timeval into the
+ * buffer after the magic character.  We then wake up anyone waiting
+ * for the buffer and return the whole mess on the next read.
+ *
+ * To use this the calling program is expected to first open the
+ * port, and then to set the port into raw mode with the speed
+ * set appropriately with a TIOCSETP ioctl(), with the erase and kill
+ * characters set to those to be considered magic (yes, I know this
+ * is gross, but they were so convenient).  If only one character is
+ * magic you can set then both the same, or perhaps to the alternate
+ * parity versions of said character.  After getting all this set,
+ * change the line discipline to CLKLDISC and you are on your way.
+ *
+ * The only other bit of magic we do in here is to flush the receive
+ * buffers on writes if the CRMOD flag is set (hack, hack).
+ */
+
+/*
+ * We run this very much like a raw mode terminal, with the exception
+ * that we store up characters locally until we hit one of the
+ * magic ones and then dump it into the rawq all at once.  We keep
+ * the buffered data in clists since we can then often move it to
+ * the rawq without copying.  For sanity we limit the number of
+ * characters between specials, and the total number of characters
+ * before we flush the rawq, as follows.
+ */
+#define	CLKLINESIZE	(256)
+#define	NCLKCHARS	(CLKLINESIZE*4)
+
+struct clkdata {
+	int inuse;
+	struct clist clkbuf;
+};
+#define	clk_cc	clkbuf.c_cc
+#define	clk_cf	clkbuf.c_cf
+#define	clk_cl	clkbuf.c_cl
+
+struct clkdata clk_data[NCLK];
+
+/*
+ * Routine for flushing the internal clist
+ */
+#define	clk_bflush(clk)		(ndflush(&((clk)->clkbuf), (clk)->clk_cc))
+
+int clk_debug = 0;
+
+/*ARGSUSED*/
+clkopen(dev, tp)
+	dev_t dev;
+	register struct tty *tp;
+{
+	register struct clkdata *clk;
+
+	/*
+	 * Don't allow multiple opens.  This will also protect us
+	 * from someone opening /dev/tty
+	 */
+	if (tp->t_line == CLKLDISC)
+		return (EBUSY);
+	ttywflush(tp);
+	for (clk = clk_data; clk < &clk_data[NCLK]; clk++)
+		if (!clk->inuse)
+			break;
+	if (clk >= &clk_data[NCLK])
+		return (EBUSY);
+	clk->inuse++;
+	clk->clk_cc = 0;
+	clk->clk_cf = clk->clk_cl = NULL;
+	tp->T_LINEP = (caddr_t) clk;
+	return (0);
+}
+
+
+/*
+ * Break down... called when discipline changed or from device
+ * close routine.
+ */
+clkclose(tp)
+	register struct tty *tp;
+{
+	register struct clkdata *clk;
+	register int s = spltty();
+
+	clk = (struct clkdata *)tp->T_LINEP;
+	if (clk->clk_cc > 0)
+		clk_bflush(clk);
+	clk->inuse = 0;
+	tp->t_line = 0;			/* paranoid: avoid races */
+	splx(s);
+}
+
+
+/*
+ * Receive a write request.  We pass these requests on to the terminal
+ * driver, except that if the CRMOD bit is set in the flags we
+ * first flush the input queues.
+ */
+clkwrite(tp, uio)
+	register struct tty *tp;
+	struct uio *uio;
+{
+	if (tp->t_flags & CRMOD) {
+		register struct clkdata *clk;
+		int s;
+
+		s = spltty();
+		if (tp->t_rawq.c_cc > 0)
+			ndflush(&tp->t_rawq, tp->t_rawq.c_cc);
+		clk = (struct clkdata *) tp->T_LINEP;
+		if (clk->clk_cc > 0)
+			clk_bflush(clk);
+		(void)splx(s);
+	}
+	ttwrite(tp, uio);
+}
+
+
+/*
+ * Low level character input routine.
+ * If the character looks okay, grab a time stamp.  If the stuff in
+ * the buffer is too old, dump it and start fresh.  If the character is
+ * non-BCDish, everything in the buffer too.
+ */
+clkinput(c, tp)
+	register int c;
+	register struct tty *tp;
+{
+	register struct clkdata *clk;
+	register int i;
+	register long s;
+	struct timeval tv;
+
+	/*
+	 * Check to see whether this isn't the magic character.  If not,
+	 * save the character and return.
+	 */
+#ifdef ultrix
+	if (c != tp->t_cc[VERASE] && c != tp->t_cc[VKILL]) {
+#else
+	if (c != tp->t_erase && c != tp->t_kill) {
+#endif
+		clk = (struct clkdata *) tp->T_LINEP;
+		if (clk->clk_cc >= CLKLINESIZE)
+			clk_bflush(clk);
+		if (putc(c, &clk->clkbuf) == -1) {
+			/*
+			 * Hopeless, no clists.  Flush what we have
+			 * and hope things improve.
+			 */
+			clk_bflush(clk);
+		}
+		return;
+	}
+
+	/*
+	 * Here we have a magic character.  Get a timestamp and store
+	 * everything.
+	 */
+	microtime(&tv);
+	clk = (struct clkdata *) tp->T_LINEP;
+
+	if (putc(c, &clk->clkbuf) == -1)
+		goto flushout;
+	
+#ifdef CLKLDISC
+	/*
+	 * STREAMS people started writing timestamps this way.
+	 * It's not my fault, I am just going along with the flow...
+	 */
+	for (i = 0; i < sizeof(struct timeval); i++)
+		if (putc(*( ((char*)&tv) + i ), &clk->clkbuf) == -1)
+			goto flushout;
+#else
+	/*
+	 * This is a machine independant way of puting longs into
+	 * the datastream.  It has fallen into disuse...
+	 */
+	s = tv.tv_sec;
+	for (i = 0; i < sizeof(long); i++) {
+		if (putc((s >> 24) & 0xff, &clk->clkbuf) == -1)
+			goto flushout;
+		s <<= 8;
+	}
+
+	s = tv.tv_usec;
+	for (i = 0; i < sizeof(long); i++) {
+		if (putc((s >> 24) & 0xff, &clk->clkbuf) == -1)
+			goto flushout;
+		s <<= 8;
+	}
+#endif
+
+	/*
+	 * If the length of the rawq exceeds our sanity limit, dump
+	 * all the old crap in there before copying this in.
+	 */
+	if (tp->t_rawq.c_cc > NCLKCHARS)
+		ndflush(&tp->t_rawq, tp->t_rawq.c_cc);
+	
+	/*
+	 * Now copy the buffer in.  There is a special case optimization
+	 * here.  If there is nothing on the rawq at present we can
+	 * just copy the clists we own over.  Otherwise we must concatenate
+	 * the present data on the end.
+	 */
+	s = (long)spltty();
+	if (tp->t_rawq.c_cc <= 0) {
+		tp->t_rawq = clk->clkbuf;
+		clk->clk_cc = 0;
+		clk->clk_cl = clk->clk_cf = NULL;
+		(void) splx((int)s);
+	} else {
+		(void) splx((int)s);
+		catq(&clk->clkbuf, &tp->t_rawq);
+		clk_bflush(clk);
+	}
+
+	/*
+	 * Tell the world
+	 */
+	ttwakeup(tp);
+	return;
+
+flushout:
+	/*
+	 * It would be nice if this never happened.  Flush the
+	 * internal clists and hope someone else frees some of them
+	 */
+	clk_bflush(clk);
+	return;
+}
+
+
+/*
+ * Handle ioctls.  We reject most tty-style except those that
+ * change the line discipline and a couple of others..
+ */
+clkioctl(tp, cmd, data, flag)
+	struct tty *tp;
+	int cmd;
+	caddr_t data;
+	int flag;
+{
+	int flags;
+	struct sgttyb *sg;
+
+	if ((cmd>>8) != 't')
+		return (-1);
+	switch (cmd) {
+	case TIOCSETD:
+	case TIOCGETD:
+	case TIOCGETP:
+	case TIOCGETC:
+	case TIOCOUTQ:
+		return (-1);
+
+	case TIOCSETP:
+		/*
+		 * He likely wants to set new magic characters in.
+		 * Do this part.
+		 */
+		sg = (struct sgttyb *)data;
+#ifdef ultrix
+		tp->t_cc[VERASE] = sg->sg_erase;
+		tp->t_cc[VKILL] = sg->sg_kill;
+#else
+		tp->t_erase = sg->sg_erase;
+		tp->t_kill = sg->sg_kill;
+#endif
+		return (0);
+
+	case TIOCFLUSH:
+		flags = *(int *)data;
+		if (flags == 0 || (flags & FREAD)) {
+			register struct clkdata *clk;
+
+			clk = (struct clkdata *) tp->T_LINEP;
+			if (clk->clk_cc > 0)
+				clk_bflush(clk);
+		}
+		return (-1);
+	
+	default:
+		break;
+	}
+	return (ENOTTY);	/* not quite appropriate */
+}
+#endif NCLK