patch-2.4.20 linux-2.4.20/arch/ppc/platforms/chrp_time.c

• Lines: 196
• Date: Thu Nov 28 15:53:11 2002
• Orig file: linux-2.4.19/arch/ppc/platforms/chrp_time.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -urN linux-2.4.19/arch/ppc/platforms/chrp_time.c linux-2.4.20/arch/ppc/platforms/chrp_time.c
@@ -0,0 +1,195 @@
+/*
+ * BK Id: %F% %I% %G% %U% %#%
+ */
+/*
+ *  arch/ppc/platforms/chrp_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 arch/i386/kernel/time.c
+ *
+ */
+#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/time.h>
+#include <linux/timex.h>
+#include <linux/kernel_stat.h>
+#include <linux/mc146818rtc.h>
+#include <linux/init.h>
+
+#include <asm/segment.h>
+#include <asm/io.h>
+#include <asm/processor.h>
+#include <asm/nvram.h>
+#include <asm/prom.h>
+#include <asm/sections.h>
+#include <asm/time.h>
+
+extern spinlock_t rtc_lock;
+
+static int nvram_as1 = NVRAM_AS1;
+static int nvram_as0 = NVRAM_AS0;
+static int nvram_data = NVRAM_DATA;
+
+long __init chrp_time_init(void)
+{
+	struct device_node *rtcs;
+	int base;
+
+	rtcs = find_compatible_devices("rtc", "pnpPNP,b00");
+	if (rtcs == NULL || rtcs->addrs == NULL)
+		return 0;
+	base = rtcs->addrs[0].address;
+	nvram_as1 = 0;
+	nvram_as0 = base;
+	nvram_data = base + 1;
+
+	return 0;
+}
+
+int __chrp chrp_cmos_clock_read(int addr)
+{
+	if (nvram_as1 != 0)
+		outb(addr>>8, nvram_as1);
+	outb(addr, nvram_as0);
+	return (inb(nvram_data));
+}
+
+void __chrp chrp_cmos_clock_write(unsigned long val, int addr)
+{
+	if (nvram_as1 != 0)
+		outb(addr>>8, nvram_as1);
+	outb(addr, nvram_as0);
+	outb(val, nvram_data);
+	return;
+}
+
+/*
+ * Set the hardware clock. -- Cort
+ */
+int __chrp chrp_set_rtc_time(unsigned long nowtime)
+{
+	unsigned char save_control, save_freq_select;
+	struct rtc_time tm;
+
+	spin_lock(&rtc_lock);
+	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;
+	spin_unlock(&rtc_lock);
+	return 0;
+}
+
+unsigned long __chrp chrp_get_rtc_time(void)
+{
+	unsigned int year, mon, day, hour, min, sec;
+	int uip, 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.
+	 */
+
+	/* Since the UIP flag is set for about 2.2 ms and the clock
+	 * is typically written with a precision of 1 jiffy, trying
+	 * to obtain a precision better than a few milliseconds is 
+	 * an illusion. Only consistency is interesting, this also
+	 * allows to use the routine for /dev/rtc without a potential
+	 * 1 second kernel busy loop triggered by any reader of /dev/rtc. 
+	 */
+
+	for ( i = 0; i<1000000; i++) {
+		uip = chrp_cmos_clock_read(RTC_FREQ_SELECT);
+		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);
+		uip |= chrp_cmos_clock_read(RTC_FREQ_SELECT);
+		if ((uip & RTC_UIP)==0) break;
+	}
+
+	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);
+}
+
+
+void __init chrp_calibrate_decr(void)
+{
+	struct device_node *cpu;
+	unsigned int freq, *fp;
+
+	if (via_calibrate_decr())
+		return;
+
+	/*
+	 * The cpu node should have a timebase-frequency property
+	 * to tell us the rate at which the decrementer counts.
+	 */
+	freq = 16666000;		/* hardcoded default */
+	cpu = find_type_devices("cpu");
+	if (cpu != 0) {
+		fp = (unsigned int *)
+			get_property(cpu, "timebase-frequency", NULL);
+		if (fp != 0)
+			freq = *fp;
+	}
+	printk("time_init: decrementer frequency = %u.%.6u MHz\n",
+ 	       freq/1000000, freq%1000000);
+	tb_ticks_per_jiffy = freq / HZ;
+	tb_to_us = mulhwu_scale_factor(freq, 1000000);
+}