1 files changed, 152 insertions, 0 deletions

diff --git a/arch/sh/boards/mpc1211/rtc.c b/arch/sh/boards/mpc1211/rtc.c
new file mode 100644
index 000000000000..4d100f048072
--- /dev/null
+++ b/arch/sh/boards/mpc1211/rtc.c
@@ -0,0 +1,152 @@
+/*
+ * linux/arch/sh/kernel/rtc-mpc1211.c -- MPC-1211 on-chip RTC support
+ *
+ *  Copyright (C) 2002  Saito.K & Jeanne
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/time.h>
+#include <linux/mc146818rtc.h>
+
+#ifndef BCD_TO_BIN
+#define BCD_TO_BIN(val) ((val)=((val)&15) + ((val)>>4)*10)
+#endif
+
+#ifndef BIN_TO_BCD
+#define BIN_TO_BCD(val) ((val)=(((val)/10)<<4) + (val)%10)
+#endif
+
+/* arc/i386/kernel/time.c */
+unsigned long get_cmos_time(void)
+{
+        unsigned int year, mon, day, hour, min, sec;
+        int i;
+
+        spin_lock(&rtc_lock);
+        /* The Linux interpretation of the CMOS clock register contents:
+         * When the Update-In-Progress (UIP) flag goes from 1 to 0, the
+         * RTC registers show the second which has precisely just started.
+         * Let's hope other operating systems interpret the RTC the same way.
+         */
+        /* read RTC exactly on falling edge of update flag */
+        for (i = 0 ; i < 1000000 ; i++) /* may take up to 1 second... */
+                if (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP)
+                        break;
+        for (i = 0 ; i < 1000000 ; i++) /* must try at least 2.228 ms */
+                if (!(CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP))
+                        break;
+        do { /* Isn't this overkill ? UIP above should guarantee consistency */
+                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(&rtc_lock);
+        if ((year += 1900) < 1970)
+                year += 100;
+        return mktime(year, mon, day, hour, min, sec);
+}
+
+void mpc1211_rtc_gettimeofday(struct timeval *tv)
+{
+
+        tv->tv_sec = get_cmos_time();
+        tv->tv_usec = 0;
+}
+
+/* arc/i386/kernel/time.c */
+/*
+ * 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)
+{
+        int retval = 0;
+        int real_seconds, real_minutes, cmos_minutes;
+        unsigned char save_control, save_freq_select;
+
+        /* 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)
+                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(&rtc_lock);
+
+        return retval;
+}
+
+int mpc1211_rtc_settimeofday(const struct timeval *tv)
+{
+        unsigned long nowtime = tv->tv_sec;
+
+        return set_rtc_mmss(nowtime);
+}
+
+void mpc1211_time_init(void)
+{
+        rtc_get_time = mpc1211_rtc_gettimeofday;
+        rtc_set_time = mpc1211_rtc_settimeofday;
+}
+