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authorRalf Baechle <ralf@linux-mips.org>2008-09-16 19:48:51 +0200
committerRalf Baechle <ralf@linux-mips.org>2008-10-11 16:18:52 +0100
commit384740dc49ea651ba350704d13ff6be9976e37fe (patch)
treea6e80cad287ccae7a86d81bfa692fc96889c88ed /arch/mips/include/asm/mc146818-time.h
parente8c7c482347574ecdd45c43e32c332d5fc2ece61 (diff)
MIPS: Move headfiles to new location below arch/mips/include
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/include/asm/mc146818-time.h')
-rw-r--r--arch/mips/include/asm/mc146818-time.h119
1 files changed, 119 insertions, 0 deletions
diff --git a/arch/mips/include/asm/mc146818-time.h b/arch/mips/include/asm/mc146818-time.h
new file mode 100644
index 000000000000..cdc379a0a94e
--- /dev/null
+++ b/arch/mips/include/asm/mc146818-time.h
@@ -0,0 +1,119 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Machine dependent access functions for RTC registers.
+ */
+#ifndef __ASM_MC146818_TIME_H
+#define __ASM_MC146818_TIME_H
+
+#include <linux/bcd.h>
+#include <linux/mc146818rtc.h>
+#include <linux/time.h>
+
+/*
+ * For check timing call set_rtc_mmss() 500ms; used in timer interrupt.
+ */
+#define USEC_AFTER 500000
+#define USEC_BEFORE 500000
+
+/*
+ * 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 inline int mc146818_set_rtc_mmss(unsigned long nowtime)
+{
+ int real_seconds, real_minutes, cmos_minutes;
+ unsigned char save_control, save_freq_select;
+ int retval = 0;
+ unsigned long flags;
+
+ spin_lock_irqsave(&rtc_lock, flags);
+ 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)
+ BCD_TO_BIN(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)
+ real_minutes += 30; /* correct for half hour time zone */
+ real_minutes %= 60;
+
+ if (abs(real_minutes - cmos_minutes) < 30) {
+ if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
+ BIN_TO_BCD(real_seconds);
+ BIN_TO_BCD(real_minutes);
+ }
+ CMOS_WRITE(real_seconds, RTC_SECONDS);
+ CMOS_WRITE(real_minutes, RTC_MINUTES);
+ } else {
+ printk(KERN_WARNING
+ "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_irqrestore(&rtc_lock, flags);
+
+ return retval;
+}
+
+static inline unsigned long mc146818_get_cmos_time(void)
+{
+ unsigned int year, mon, day, hour, min, sec;
+ unsigned long flags;
+
+ spin_lock_irqsave(&rtc_lock, flags);
+
+ do {
+ sec = CMOS_READ(RTC_SECONDS);
+ min = CMOS_READ(RTC_MINUTES);
+ hour = CMOS_READ(RTC_HOURS);
+ day = CMOS_READ(RTC_DAY_OF_MONTH);
+ mon = CMOS_READ(RTC_MONTH);
+ year = CMOS_READ(RTC_YEAR);
+ } while (sec != CMOS_READ(RTC_SECONDS));
+
+ if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
+ BCD_TO_BIN(sec);
+ BCD_TO_BIN(min);
+ BCD_TO_BIN(hour);
+ BCD_TO_BIN(day);
+ BCD_TO_BIN(mon);
+ BCD_TO_BIN(year);
+ }
+ spin_unlock_irqrestore(&rtc_lock, flags);
+ year = mc146818_decode_year(year);
+
+ return mktime(year, mon, day, hour, min, sec);
+}
+
+#endif /* __ASM_MC146818_TIME_H */