patch-2.1.53 linux/arch/ppc/kernel/chrp_time.c

• Lines: 133
• Date: Thu Sep 4 12:54:48 1997
• Orig file: v2.1.52/linux/arch/ppc/kernel/chrp_time.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.52/linux/arch/ppc/kernel/chrp_time.c linux/arch/ppc/kernel/chrp_time.c
@@ -0,0 +1,132 @@
+/*
+ *  linux/arch/i386/kernel/time.c
+ *
+ *  Copyright (C) 1991, 1992, 1995  Linus Torvalds
+ *
+ * Adapted for PowerPC (PreP) by Gary Thomas
+ * Modified by Cort Dougan (cort@cs.nmt.edu)
+ *  copied and modified from intel version
+ *
+ */
+#include <linux/config.h>
+#include <linux/errno.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/param.h>
+#include <linux/string.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+#include <linux/timex.h>
+#include <linux/kernel_stat.h>
+#include <linux/mc146818rtc.h>
+
+#include <asm/segment.h>
+#include <asm/io.h>
+#include <asm/processor.h>
+#include <asm/nvram.h>
+
+#include "time.h"
+
+int chrp_cmos_clock_read(int addr)
+{
+	outb(addr>>8, NVRAM_AS1);
+	outb(addr, NVRAM_AS0);
+	return (inb(NVRAM_DATA));
+}
+
+void chrp_cmos_clock_write(unsigned long val, int addr)
+{
+	outb(addr>>8, NVRAM_AS1);
+	outb(addr, NVRAM_AS0);
+	outb(val,NVRAM_DATA);
+	return;
+}
+
+/*
+ * Set the hardware clock. -- Cort
+ */
+int chrp_set_rtc_time(unsigned long nowtime)
+{
+	unsigned char save_control, save_freq_select;
+	struct rtc_time tm;
+
+	to_tm(nowtime, &tm);
+
+	save_control = chrp_cmos_clock_read(RTC_CONTROL); /* tell the clock it's being set */
+
+	chrp_cmos_clock_write((save_control|RTC_SET), RTC_CONTROL);
+
+	save_freq_select = chrp_cmos_clock_read(RTC_FREQ_SELECT); /* stop and reset prescaler */
+	
+	chrp_cmos_clock_write((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
+
+        tm.tm_year -= 1900;
+	if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
+		BIN_TO_BCD(tm.tm_sec);
+		BIN_TO_BCD(tm.tm_min);
+		BIN_TO_BCD(tm.tm_hour);
+		BIN_TO_BCD(tm.tm_mon);
+		BIN_TO_BCD(tm.tm_mday);
+		BIN_TO_BCD(tm.tm_year);
+	}
+	chrp_cmos_clock_write(tm.tm_sec,RTC_SECONDS);
+	chrp_cmos_clock_write(tm.tm_min,RTC_MINUTES);
+	chrp_cmos_clock_write(tm.tm_hour,RTC_HOURS);
+	chrp_cmos_clock_write(tm.tm_mon,RTC_MONTH);
+	chrp_cmos_clock_write(tm.tm_mday,RTC_DAY_OF_MONTH);
+	chrp_cmos_clock_write(tm.tm_year,RTC_YEAR);
+	
+	/* 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
+	 */
+	chrp_cmos_clock_write(save_control, RTC_CONTROL);
+	chrp_cmos_clock_write(save_freq_select, RTC_FREQ_SELECT);
+
+	if ( (time_state == TIME_ERROR) || (time_state == TIME_BAD) )
+		time_state = TIME_OK;
+	return 0;
+}
+
+unsigned long chrp_get_rtc_time(void)
+{
+	unsigned int year, mon, day, hour, min, sec;
+	int i;
+
+	/* 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 (chrp_cmos_clock_read(RTC_FREQ_SELECT) & RTC_UIP)
+			break;
+	for (i = 0 ; i < 1000000 ; i++)	/* must try at least 2.228 ms */
+		if (!(chrp_cmos_clock_read(RTC_FREQ_SELECT) & RTC_UIP))
+			break;
+	do { /* Isn't this overkill ? UIP above should guarantee consistency */
+		sec = chrp_cmos_clock_read(RTC_SECONDS);
+		min = chrp_cmos_clock_read(RTC_MINUTES);
+		hour = chrp_cmos_clock_read(RTC_HOURS);
+		day = chrp_cmos_clock_read(RTC_DAY_OF_MONTH);
+		mon = chrp_cmos_clock_read(RTC_MONTH);
+		year = chrp_cmos_clock_read(RTC_YEAR);
+	} while (sec != chrp_cmos_clock_read(RTC_SECONDS));
+	if (!(chrp_cmos_clock_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);
+	  }
+	if ((year += 1900) < 1970)
+		year += 100;
+	return mktime(year, mon, day, hour, min, sec);
+}
+