Add support for using uart(4) for pulse capturing for the Pulse Per

Second (PPS) timing interface. The support is non-optional and by
default uses the DCD line signal as the pulse input. A compile-time
option (UART_PPS_ON_CTS) can be used to have uart(4) use the CTS line
signal.

Include <sys/timepps.h> in uart_bus.h to avoid having to add the
inclusion of that header in all source files.

Reviewed by: phk

5 files changed, 45 insertions, 2 deletions

diff --git a/sys/conf/NOTES b/sys/conf/NOTES
index a85846b..e5ae8a4 100644
--- a/sys/conf/NOTES
+++ b/sys/conf/NOTES
@@ -1465,6 +1465,10 @@ options 	CONSPEED=115200		# Speed for serial console
 #
 device		uart
 
+# Options for uart(4)
+options 	UART_PPS_ON_CTS		# Do time pulse capturing using CTS
+					# instead of DCD.
+
 # The following hint should only be used for pure ISA devices.  It is not
 # needed otherwise.  Use of hints is strongly discouraged.
 hint.uart.0.at="isa"
diff --git a/sys/conf/options b/sys/conf/options
index 0992646..38b1d01 100644
--- a/sys/conf/options
+++ b/sys/conf/options
@@ -537,6 +537,9 @@ COM_MULTIPORT		opt_sio.h
 BREAK_TO_DEBUGGER	opt_comconsole.h
 ALT_BREAK_TO_DEBUGGER	opt_comconsole.h
 
+# Options to support PPS
+UART_PPS_ON_CTS		opt_uart.h
+
 # options for bus/device framework
 BUS_DEBUG		opt_bus.h
 
diff --git a/sys/dev/uart/uart_bus.h b/sys/dev/uart/uart_bus.h
index 71aa1be..bd0bab7 100644
--- a/sys/dev/uart/uart_bus.h
+++ b/sys/dev/uart/uart_bus.h
@@ -29,6 +29,12 @@
 #ifndef _DEV_UART_BUS_H_
 #define _DEV_UART_BUS_H_
 
+#ifndef KLD_MODULE
+#include "opt_uart.h"
+#endif
+
+#include <sys/timepps.h>
+
 /* Drain and flush targets. */
 #define	UART_DRAIN_RECEIVER	0x0001
 #define	UART_DRAIN_TRANSMITTER	0x0002
@@ -75,6 +81,14 @@
 #define	UART_SIGMASK_STATE	0x003f
 #define	UART_SIGMASK_DELTA	0x3f00
 
+#ifdef UART_PPS_ON_CTS
+#define	UART_SIG_DPPS		UART_SIG_DCTS
+#define	UART_SIG_PPS		UART_SIG_CTS
+#else
+#define	UART_SIG_DPPS		UART_SIG_DDCD
+#define	UART_SIG_PPS		UART_SIG_DCD
+#endif
+
 /* UART_IOCTL() requests */
 #define	UART_IOCTL_BREAK	1
 #define	UART_IOCTL_IFLOW	2
@@ -133,6 +147,9 @@ struct uart_softc {
 	int		sc_txdatasz;
 	int		sc_txfifosz;	/* Size of TX FIFO and buffer. */
 
+	/* Pulse capturing support (PPS). */
+	struct pps_state sc_pps;
+
 	/* Upper layer data. */
 	void		*sc_softih;
 	uint32_t	sc_ttypend;
diff --git a/sys/dev/uart/uart_core.c b/sys/dev/uart/uart_core.c
index 450313a..883bea2 100644
--- a/sys/dev/uart/uart_core.c
+++ b/sys/dev/uart/uart_core.c
@@ -162,6 +162,15 @@ uart_intr_sigchg(struct uart_softc *sc)
 	int new, old, sig;
 
 	sig = UART_GETSIG(sc);
+
+	if (sc->sc_pps.ppsparam.mode & PPS_CAPTUREBOTH) {
+		if (sig & UART_SIG_DPPS) {
+			pps_capture(&sc->sc_pps);
+			pps_event(&sc->sc_pps, (sig & UART_SIG_PPS) ?
+			    PPS_CAPTUREASSERT : PPS_CAPTURECLEAR);
+		}
+	}
+
 	do {
 		old = sc->sc_ttypend;
 		new = old & ~UART_SIGMASK_STATE;
@@ -393,6 +402,9 @@ uart_bus_attach(device_t dev)
 		    sc->sc_sysdev->stopbits);
 	}
 
+	sc->sc_pps.ppscap = PPS_CAPTUREBOTH;
+	pps_init(&sc->sc_pps);
+
 	error = (sc->sc_sysdev != NULL && sc->sc_sysdev->attach != NULL)
 	    ? (*sc->sc_sysdev->attach)(sc) : uart_tty_attach(sc);
 	if (error)
diff --git a/sys/dev/uart/uart_tty.c b/sys/dev/uart/uart_tty.c
index 3841889..2814e6d 100644
--- a/sys/dev/uart/uart_tty.c
+++ b/sys/dev/uart/uart_tty.c
@@ -476,6 +476,9 @@ uart_tty_close(dev_t dev, int flags, int mode, struct thread *td)
 	if (sc->sc_sysdev == NULL)
 		UART_SETSIG(sc, UART_SIG_DDTR | UART_SIG_DRTS);
 
+	/* Disable pulse capturing. */
+	sc->sc_pps.ppsparam.mode = 0;
+
 	(*linesw[tp->t_line].l_close)(tp, flags);
 	ttyclose(tp);
 	wakeup(sc);
@@ -505,6 +508,7 @@ uart_tty_ioctl(dev_t dev, u_long cmd, caddr_t data, int flags,
 	if (error != ENOIOCTL)
 		return (error);
 
+	error = 0;
 	switch (cmd) {
 	case TIOCSBRK:
 		UART_IOCTL(sc, UART_IOCTL_BREAK, 1);
@@ -563,7 +567,10 @@ uart_tty_ioctl(dev_t dev, u_long cmd, caddr_t data, int flags,
 		*(int*)data = bits;
 		break;
 	default:
-		return (ENOTTY);
+		error = pps_ioctl(cmd, data, &sc->sc_pps);
+		if (error == ENODEV)
+			error = ENOTTY;
+		break;
 	}
-	return (0);
+	return (error);
 }