readclock: add support for am335x RTC

Add support for getting/setting the am335x SoC's internal real
time clock. Also, allow the power off alarm to be set.

Make readclock an "always on" driver. This is needed for setting
power-off alarms whenever the power button is pressed on the BBB.

Replace the readclock.sh script & single run driver with a
readclock program that takes the same arguments and forwards
the requests on to the always up readclock driver.

Change-Id: Ifd6c2acd80ae4b5e79d83df510df445c24e24a71

commands/readclock/Makefile

@@ -1,5 +1,8 @@
-SCRIPTS= readclock.sh
+PROG=	readclock
+SRCS=	readclock.c
 BINDIR= /bin
+
+# no man page here, it's handled in ../man/man8/
 MAN=
 
 .include <bsd.prog.mk>

commands/readclock/readclock.c

@@ -0,0 +1,191 @@
+/* frontend to the readclock.drv driver for getting/setting hw clock. */
+
+#include <sys/cdefs.h>
+#include <lib.h>
+#include <sys/types.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <time.h>
+#include <errno.h>
+#include <minix/type.h>
+#include <minix/const.h>
+#include <minix/syslib.h>
+#include <minix/sysutil.h>
+#include <minix/com.h>
+#include <minix/rs.h>
+#include <sys/ipc.h>
+
+int nflag = 0;			/* Tell what, but don't do it. */
+int wflag = 0;			/* Set the CMOS clock. */
+int Wflag = 0;			/* Also set the CMOS clock register bits. */
+int y2kflag = 0;		/* Interpret 1980 as 2000 for clock with Y2K bug. */
+
+void errmsg(char *s);
+void get_time(struct tm *t);
+void set_time(struct tm *t);
+void usage(void);
+
+int
+main(int argc, char **argv)
+{
+	struct tm time1;
+	struct tm time2;
+	struct tm tmnow;
+	char date[64];
+	time_t now, rtc;
+	int i, s;
+
+	/* Process options. */
+	while (argc > 1) {
+		char *p = *++argv;
+
+		if (*p++ != '-')
+			usage();
+
+		while (*p != 0) {
+			switch (*p++) {
+			case 'n':
+				nflag = 1;
+				break;
+			case 'w':
+				wflag = 1;
+				break;
+			case 'W':
+				Wflag = 1;
+				break;
+			case '2':
+				y2kflag = 1;
+				break;
+			default:
+				usage();
+			}
+		}
+		argc--;
+	}
+	if (Wflag)
+		wflag = 1;	/* -W implies -w */
+
+	/* Read the CMOS real time clock. */
+	for (i = 0; i < 10; i++) {
+		get_time(&time1);
+		now = time(NULL);
+
+		time1.tm_isdst = -1;	/* Do timezone calculations. */
+		time2 = time1;
+
+		rtc = mktime(&time1);	/* Transform to a time_t. */
+		if (rtc != -1)
+			break;
+
+		printf
+		    ("readclock: Invalid time read from CMOS RTC: %d-%02d-%02d %02d:%02d:%02d\n",
+		    time2.tm_year + 1900, time2.tm_mon + 1, time2.tm_mday,
+		    time2.tm_hour, time2.tm_min, time2.tm_sec);
+		sleep(5);
+	}
+	if (i == 10)
+		exit(1);
+
+	if (!wflag) {
+		/* Set system time. */
+		if (nflag) {
+			printf("stime(%lu)\n", (unsigned long) rtc);
+		} else {
+			if (stime(&rtc) < 0) {
+				errmsg("Not allowed to set time.");
+				exit(1);
+			}
+		}
+		tmnow = *localtime(&rtc);
+		if (strftime(date, sizeof(date),
+			"%a %b %d %H:%M:%S %Z %Y", &tmnow) != 0) {
+			if (date[8] == '0')
+				date[8] = ' ';
+			printf("%s\n", date);
+		}
+	} else {
+		/* Set the CMOS clock to the system time. */
+		tmnow = *localtime(&now);
+		if (nflag) {
+			printf("%04d-%02d-%02d %02d:%02d:%02d\n",
+			    tmnow.tm_year + 1900,
+			    tmnow.tm_mon + 1,
+			    tmnow.tm_mday,
+			    tmnow.tm_hour, tmnow.tm_min, tmnow.tm_sec);
+		} else {
+			set_time(&tmnow);
+		}
+	}
+	exit(0);
+}
+
+void
+errmsg(char *s)
+{
+	static char *prompt = "readclock: ";
+
+	printf("%s%s\n", prompt, s);
+	prompt = "";
+}
+
+void
+get_time(struct tm *t)
+{
+	int r;
+	message m;
+	endpoint_t ep;
+
+	r = minix_rs_lookup("readclock.drv", &ep);
+	if (r != 0) {
+		errmsg("Couldn't locate readclock.drv\n");
+		exit(1);
+	}
+
+	m.RTCDEV_TM = t;
+	m.RTCDEV_FLAGS = (y2kflag) ? RTCDEV_Y2KBUG : RTCDEV_NOFLAGS;
+
+	r = _syscall(ep, RTCDEV_GET_TIME, &m);
+	if (r != RTCDEV_REPLY || m.RTCDEV_STATUS != 0) {
+		errmsg("Call to readclock.drv failed\n");
+		exit(1);
+	}
+}
+
+void
+set_time(struct tm *t)
+{
+	int r;
+	message m;
+	endpoint_t ep;
+
+	r = minix_rs_lookup("readclock.drv", &ep);
+	if (r != 0) {
+		errmsg("Couldn't locate readclock.drv\n");
+		exit(1);
+	}
+
+	m.RTCDEV_TM = t;
+	m.RTCDEV_FLAGS = RTCDEV_NOFLAGS;
+
+	if (y2kflag) {
+		m.RTCDEV_FLAGS |= RTCDEV_Y2KBUG;
+	}
+
+	if (Wflag) {
+		m.RTCDEV_FLAGS |= RTCDEV_CMOSREG;
+	}
+
+	r = _syscall(ep, RTCDEV_SET_TIME, &m);
+	if (r != RTCDEV_REPLY || m.RTCDEV_STATUS != 0) {
+		errmsg("Call to readclock.drv failed\n");
+		exit(1);
+	}
+}
+
+void
+usage(void)
+{
+	printf("Usage: readclock [-nwW2]\n");
+	exit(1);
+}

commands/readclock/readclock.sh

@@ -1,5 +0,0 @@
-#!/bin/sh
-if [ $# -gt 0 ]
-then	ARGS="-args $@"
-fi
-/bin/service up /sbin/readclock.drv -period 5HZ -script /etc/rs.single $ARGS