Initial import

1 files changed, 132 insertions, 0 deletions

diff --git a/arch/mn10300/kernel/rtc.c b/arch/mn10300/kernel/rtc.c
new file mode 100644
index 000000000..48d7058b3
--- /dev/null
+++ b/arch/mn10300/kernel/rtc.c
@@ -0,0 +1,132 @@
+/* MN10300 RTC management
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/mc146818rtc.h>
+#include <linux/bcd.h>
+#include <linux/timex.h>
+#include <asm/rtc-regs.h>
+#include <asm/rtc.h>
+
+DEFINE_SPINLOCK(rtc_lock);
+EXPORT_SYMBOL(rtc_lock);
+
+/*
+ * Read the current RTC time
+ */
+void read_persistent_clock(struct timespec *ts)
+{
+	struct rtc_time tm;
+
+	get_rtc_time(&tm);
+
+	ts->tv_nsec = 0;
+	ts->tv_sec = mktime(tm.tm_year, tm.tm_mon, tm.tm_mday,
+			    tm.tm_hour, tm.tm_min, tm.tm_sec);
+
+	/* if rtc is way off in the past, set something reasonable */
+	if (ts->tv_sec < 0)
+		ts->tv_sec = mktime(2009, 1, 1, 12, 0, 0);
+}
+
+/*
+ * In order to set the CMOS clock precisely, set_rtc_mmss has to be called 500
+ * ms after the second nowtime has started, because when nowtime is written
+ * into the registers of the CMOS clock, it will jump to the next second
+ * precisely 500 ms later.  Check the Motorola MC146818A or Dallas DS12887 data
+ * sheet for details.
+ *
+ * BUG: This routine does not handle hour overflow properly; it just
+ *      sets the minutes. Usually you'll only notice that after reboot!
+ */
+static int set_rtc_mmss(unsigned long nowtime)
+{
+	unsigned char save_control, save_freq_select;
+	int retval = 0;
+	int real_seconds, real_minutes, cmos_minutes;
+
+	/* gets recalled with irq locally disabled */
+	spin_lock(&rtc_lock);
+	save_control = CMOS_READ(RTC_CONTROL); /* tell the clock it's being
+						* set */
+	CMOS_WRITE(save_control | RTC_SET, RTC_CONTROL);
+
+	save_freq_select = CMOS_READ(RTC_FREQ_SELECT); /* stop and reset
+							* prescaler */
+	CMOS_WRITE(save_freq_select | RTC_DIV_RESET2, RTC_FREQ_SELECT);
+
+	cmos_minutes = CMOS_READ(RTC_MINUTES);
+	if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
+		cmos_minutes = bcd2bin(cmos_minutes);
+
+	/*
+	 * since we're only adjusting minutes and seconds,
+	 * don't interfere with hour overflow. This avoids
+	 * messing with unknown time zones but requires your
+	 * RTC not to be off by more than 15 minutes
+	 */
+	real_seconds = nowtime % 60;
+	real_minutes = nowtime / 60;
+	if (((abs(real_minutes - cmos_minutes) + 15) / 30) & 1)
+		/* correct for half hour time zone */
+		real_minutes += 30;
+	real_minutes %= 60;
+
+	if (abs(real_minutes - cmos_minutes) < 30) {
+		if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
+			real_seconds = bin2bcd(real_seconds);
+			real_minutes = bin2bcd(real_minutes);
+		}
+		CMOS_WRITE(real_seconds, RTC_SECONDS);
+		CMOS_WRITE(real_minutes, RTC_MINUTES);
+	} else {
+		printk_once(KERN_NOTICE
+		       "set_rtc_mmss: can't update from %d to %d\n",
+		       cmos_minutes, real_minutes);
+		retval = -1;
+	}
+
+	/* The following flags have to be released exactly in this order,
+	 * otherwise the DS12887 (popular MC146818A clone with integrated
+	 * battery and quartz) will not reset the oscillator and will not
+	 * update precisely 500 ms later. You won't find this mentioned in
+	 * the Dallas Semiconductor data sheets, but who believes data
+	 * sheets anyway ...                           -- Markus Kuhn
+	 */
+	CMOS_WRITE(save_control, RTC_CONTROL);
+	CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
+	spin_unlock(&rtc_lock);
+
+	return retval;
+}
+
+int update_persistent_clock(struct timespec now)
+{
+	return set_rtc_mmss(now.tv_sec);
+}
+
+/*
+ * calibrate the TSC clock against the RTC
+ */
+void __init calibrate_clock(void)
+{
+	unsigned char status;
+
+	/* make sure the RTC is running and is set to operate in 24hr mode */
+	status = RTSRC;
+	RTCRB |= RTCRB_SET;
+	RTCRB |= RTCRB_TM_24HR;
+	RTCRB &= ~RTCRB_DM_BINARY;
+	RTCRA |= RTCRA_DVR;
+	RTCRA &= ~RTCRA_DVR;
+	RTCRB &= ~RTCRB_SET;
+}