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Diffstat (limited to 'arch/mips/ddb5xxx/common/rtc_ds1386.c')
-rw-r--r--arch/mips/ddb5xxx/common/rtc_ds1386.c267
1 files changed, 267 insertions, 0 deletions
diff --git a/arch/mips/ddb5xxx/common/rtc_ds1386.c b/arch/mips/ddb5xxx/common/rtc_ds1386.c
new file mode 100644
index 000000000..ff1d81c60
--- /dev/null
+++ b/arch/mips/ddb5xxx/common/rtc_ds1386.c
@@ -0,0 +1,267 @@
+/***********************************************************************
+ *
+ * Copyright 2001 MontaVista Software Inc.
+ * Author: jsun@mvista.com or jsun@junsun.net
+ *
+ * arch/mips/ddb5xxx/common/rtc_ds1386.c
+ * low-level RTC hookups for s for Dallas 1396 chip.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ ***********************************************************************
+ */
+
+
+/*
+ * This file exports a function, rtc_ds1386_init(), which expects an
+ * uncached base address as the argument. It will set the two function
+ * pointers expected by the MIPS generic timer code.
+ */
+
+#include <linux/types.h>
+#include <linux/time.h>
+#include <linux/rtc.h>
+
+#include <asm/time.h>
+#include <asm/addrspace.h>
+
+#include <asm/ddb5xxx/debug.h>
+
+#define EPOCH 2000
+
+#undef BCD_TO_BIN
+#define BCD_TO_BIN(val) (((val)&15) + ((val)>>4)*10)
+
+#undef BIN_TO_BCD
+#define BIN_TO_BCD(val) ((((val)/10)<<4) + (val)%10)
+
+#define READ_RTC(x) *(volatile unsigned char*)(rtc_base+x)
+#define WRITE_RTC(x, y) *(volatile unsigned char*)(rtc_base+x) = y
+
+static unsigned long rtc_base;
+
+static unsigned long
+rtc_ds1386_get_time(void)
+{
+ u8 byte;
+ u8 temp;
+ unsigned int year, month, day, hour, minute, second;
+
+ /* let us freeze external registers */
+ byte = READ_RTC(0xB);
+ byte &= 0x3f;
+ WRITE_RTC(0xB, byte);
+
+ /* read time data */
+ year = BCD_TO_BIN(READ_RTC(0xA)) + EPOCH;
+ month = BCD_TO_BIN(READ_RTC(0x9) & 0x1f);
+ day = BCD_TO_BIN(READ_RTC(0x8));
+ minute = BCD_TO_BIN(READ_RTC(0x2));
+ second = BCD_TO_BIN(READ_RTC(0x1));
+
+ /* hour is special - deal with it later */
+ temp = READ_RTC(0x4);
+
+ /* enable time transfer */
+ byte |= 0x80;
+ WRITE_RTC(0xB, byte);
+
+ /* calc hour */
+ if (temp & 0x40) {
+ /* 12 hour format */
+ hour = BCD_TO_BIN(temp & 0x1f);
+ if (temp & 0x20) hour += 12; /* PM */
+ } else {
+ /* 24 hour format */
+ hour = BCD_TO_BIN(temp & 0x3f);
+ }
+
+ return mktime(year, month, day, hour, minute, second);
+}
+
+void to_tm(unsigned long tim, struct rtc_time * tm);
+static int
+rtc_ds1386_set_time(unsigned long t)
+{
+ struct rtc_time tm;
+ u8 byte;
+ u8 temp;
+ u8 year, month, day, hour, minute, second;
+
+ /* let us freeze external registers */
+ byte = READ_RTC(0xB);
+ byte &= 0x3f;
+ WRITE_RTC(0xB, byte);
+
+ /* convert */
+ to_tm(t, &tm);
+
+ /* check each field one by one */
+ year = BIN_TO_BCD(tm.tm_year - EPOCH);
+ if (year != READ_RTC(0xA)) {
+ WRITE_RTC(0xA, year);
+ }
+
+ temp = READ_RTC(0x9);
+ month = BIN_TO_BCD(tm.tm_mon);
+ if (month != (temp & 0x1f)) {
+ WRITE_RTC( 0x9,
+ (month & 0x1f) | (temp & ~0x1f) );
+ }
+
+ day = BIN_TO_BCD(tm.tm_mday);
+ if (day != READ_RTC(0x8)) {
+ WRITE_RTC(0x8, day);
+ }
+
+ temp = READ_RTC(0x4);
+ if (temp & 0x40) {
+ /* 12 hour format */
+ hour = 0x40;
+ if (tm.tm_hour > 12) {
+ hour |= 0x20 | (BIN_TO_BCD(hour-12) & 0x1f);
+ } else {
+ hour |= BIN_TO_BCD(tm.tm_hour);
+ }
+ } else {
+ /* 24 hour format */
+ hour = BIN_TO_BCD(tm.tm_hour) & 0x3f;
+ }
+ if (hour != temp) WRITE_RTC(0x4, hour);
+
+ minute = BIN_TO_BCD(tm.tm_min);
+ if (minute != READ_RTC(0x2)) {
+ WRITE_RTC(0x2, minute);
+ }
+
+ second = BIN_TO_BCD(tm.tm_sec);
+ if (second != READ_RTC(0x1)) {
+ WRITE_RTC(0x1, second);
+ }
+
+ return 0;
+}
+
+void
+rtc_ds1386_init(unsigned long base)
+{
+ unsigned char byte;
+
+ /* remember the base */
+ rtc_base = base;
+ MIPS_ASSERT((rtc_base & 0xe0000000) == KSEG1);
+
+ /* turn on RTC if it is not on */
+ byte = READ_RTC(0x9);
+ if (byte & 0x80) {
+ byte &= 0x7f;
+ WRITE_RTC(0x9, byte);
+ }
+
+ /* enable time transfer */
+ byte = READ_RTC(0xB);
+ byte |= 0x80;
+ WRITE_RTC(0xB, byte);
+
+ /* set the function pointers */
+ rtc_get_time = rtc_ds1386_get_time;
+ rtc_set_time = rtc_ds1386_set_time;
+}
+
+
+/* ================================================== */
+#define TICK_SIZE tick
+#define FEBRUARY 2
+#define STARTOFTIME 1970
+#define SECDAY 86400L
+#define SECYR (SECDAY * 365)
+#define leapyear(year) ((year) % 4 == 0)
+#define days_in_year(a) (leapyear(a) ? 366 : 365)
+#define days_in_month(a) (month_days[(a) - 1])
+
+static int month_days[12] = {
+ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
+};
+
+/*
+ * This only works for the Gregorian calendar - i.e. after 1752 (in the UK)
+ */
+static void
+GregorianDay(struct rtc_time * tm)
+{
+ int leapsToDate;
+ int lastYear;
+ int day;
+ int MonthOffset[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
+
+ lastYear=tm->tm_year-1;
+
+ /*
+ * Number of leap corrections to apply up to end of last year
+ */
+ leapsToDate = lastYear/4 - lastYear/100 + lastYear/400;
+
+ /*
+ * This year is a leap year if it is divisible by 4 except when it is
+ * divisible by 100 unless it is divisible by 400
+ *
+ * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 will be
+ */
+ if((tm->tm_year%4==0) &&
+ ((tm->tm_year%100!=0) || (tm->tm_year%400==0)) &&
+ (tm->tm_mon>2))
+ {
+ /*
+ * We are past Feb. 29 in a leap year
+ */
+ day=1;
+ }
+ else
+ {
+ day=0;
+ }
+
+ day += lastYear*365 + leapsToDate + MonthOffset[tm->tm_mon-1] +
+ tm->tm_mday;
+
+ tm->tm_wday=day%7;
+}
+
+
+void to_tm(unsigned long tim, struct rtc_time * tm)
+{
+ register int i;
+ register long hms, day;
+
+ day = tim / SECDAY;
+ hms = tim % SECDAY;
+
+ /* Hours, minutes, seconds are easy */
+ tm->tm_hour = hms / 3600;
+ tm->tm_min = (hms % 3600) / 60;
+ tm->tm_sec = (hms % 3600) % 60;
+
+ /* Number of years in days */
+ for (i = STARTOFTIME; day >= days_in_year(i); i++)
+ day -= days_in_year(i);
+ tm->tm_year = i;
+
+ /* Number of months in days left */
+ if (leapyear(tm->tm_year))
+ days_in_month(FEBRUARY) = 29;
+ for (i = 1; day >= days_in_month(i); i++)
+ day -= days_in_month(i);
+ days_in_month(FEBRUARY) = 28;
+ tm->tm_mon = i;
+
+ /* Days are what is left over (+1) from all that. */
+ tm->tm_mday = day + 1;
+
+ /*
+ * Determine the day of week
+ */
+ GregorianDay(tm);
+}
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