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

• Lines: 229
• Date: Thu Nov 28 15:53:11 2002
• Orig file: linux-2.4.19/arch/ppc/platforms/prep_time.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -urN linux-2.4.19/arch/ppc/platforms/prep_time.c linux-2.4.20/arch/ppc/platforms/prep_time.c
@@ -0,0 +1,228 @@
+/*
+ * BK Id: %F% %I% %G% %U% %#%
+ */
+/*
+ *  arch/ppc/platforms/prep_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/init.h>
+
+#include <asm/sections.h>
+#include <asm/segment.h>
+#include <asm/io.h>
+#include <asm/processor.h>
+#include <asm/machdep.h>
+#include <asm/prep_nvram.h>
+#include <asm/mk48t59.h>
+
+#include <asm/time.h>
+
+extern spinlock_t rtc_lock;
+
+/*
+ * The motorola uses the m48t18 rtc (includes DS1643) whose registers
+ * are at a higher end of nvram (1ff8-1fff) than the ibm mc146818
+ * rtc (ds1386) which has regs at addr 0-d).  The intel gets
+ * past this because the bios emulates the mc146818.
+ *
+ * Why in the world did they have to use different clocks?
+ *
+ * Right now things are hacked to check which machine we're on then
+ * use the appropriate macro.  This is very very ugly and I should
+ * probably have a function that checks which machine we're on then
+ * does things correctly transparently or a function pointer which
+ * is setup at boot time to use the correct addresses.
+ * -- Cort
+ */
+
+/*
+ * Set the hardware clock. -- Cort
+ */
+__prep
+int mc146818_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);
+
+	/* tell the clock it's being set */
+	save_control = CMOS_READ(RTC_CONTROL);
+
+	CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
+
+	/* stop and reset prescaler */
+	save_freq_select = CMOS_READ(RTC_FREQ_SELECT);
+
+	CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
+
+        tm.tm_year = (tm.tm_year - 1900) % 100;
+	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);
+	}
+	CMOS_WRITE(tm.tm_sec,  RTC_SECONDS);
+	CMOS_WRITE(tm.tm_min,  RTC_MINUTES);
+	CMOS_WRITE(tm.tm_hour, RTC_HOURS);
+	CMOS_WRITE(tm.tm_mon,  RTC_MONTH);
+	CMOS_WRITE(tm.tm_mday, RTC_DAY_OF_MONTH);
+	CMOS_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
+	 */
+	CMOS_WRITE(save_control,     RTC_CONTROL);
+	CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
+	spin_unlock(&rtc_lock);
+
+	return 0;
+}
+
+__prep
+unsigned long mc146818_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 = CMOS_READ(RTC_FREQ_SELECT);
+		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);
+		uip |= CMOS_READ(RTC_FREQ_SELECT);
+		if ((uip & RTC_UIP)==0) break;
+	}
+
+	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);
+	}
+	if ((year += 1900) < 1970)
+		year += 100;
+	return mktime(year, mon, day, hour, min, sec);
+}
+
+__prep
+int mk48t59_set_rtc_time(unsigned long nowtime)
+{
+	unsigned char save_control;
+	struct rtc_time tm;
+
+	spin_lock(&rtc_lock);
+	to_tm(nowtime, &tm);
+
+	/* tell the clock it's being written */
+	save_control = ppc_md.nvram_read_val(MK48T59_RTC_CONTROLA);
+
+	ppc_md.nvram_write_val(MK48T59_RTC_CONTROLA,
+			     (save_control | MK48T59_RTC_CA_WRITE));
+
+        tm.tm_year = (tm.tm_year - 1900) % 100;
+	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);
+
+	ppc_md.nvram_write_val(MK48T59_RTC_SECONDS,      tm.tm_sec);
+	ppc_md.nvram_write_val(MK48T59_RTC_MINUTES,      tm.tm_min);
+	ppc_md.nvram_write_val(MK48T59_RTC_HOURS,        tm.tm_hour);
+	ppc_md.nvram_write_val(MK48T59_RTC_MONTH,        tm.tm_mon);
+	ppc_md.nvram_write_val(MK48T59_RTC_DAY_OF_MONTH, tm.tm_mday);
+	ppc_md.nvram_write_val(MK48T59_RTC_YEAR,         tm.tm_year);
+
+	/* Turn off the write bit. */
+	ppc_md.nvram_write_val(MK48T59_RTC_CONTROLA, save_control);
+	spin_unlock(&rtc_lock);
+
+	return 0;
+}
+
+__prep
+unsigned long mk48t59_get_rtc_time(void)
+{
+	unsigned char save_control;
+	unsigned int year, mon, day, hour, min, sec;
+
+	/* Simple: freeze the clock, read it and allow updates again */
+	save_control = ppc_md.nvram_read_val(MK48T59_RTC_CONTROLA);
+	save_control &= ~MK48T59_RTC_CA_READ;
+	ppc_md.nvram_write_val(MK48T59_RTC_CONTROLA, save_control);
+
+	/* Set the register to read the value. */
+	ppc_md.nvram_write_val(MK48T59_RTC_CONTROLA,
+			     (save_control | MK48T59_RTC_CA_READ));
+
+	sec = ppc_md.nvram_read_val(MK48T59_RTC_SECONDS);
+	min = ppc_md.nvram_read_val(MK48T59_RTC_MINUTES);
+	hour = ppc_md.nvram_read_val(MK48T59_RTC_HOURS);
+	day = ppc_md.nvram_read_val(MK48T59_RTC_DAY_OF_MONTH);
+	mon = ppc_md.nvram_read_val(MK48T59_RTC_MONTH);
+	year = ppc_md.nvram_read_val(MK48T59_RTC_YEAR);
+
+	/* Let the time values change again. */
+	ppc_md.nvram_write_val(MK48T59_RTC_CONTROLA, save_control);
+
+	BCD_TO_BIN(sec);
+	BCD_TO_BIN(min);
+	BCD_TO_BIN(hour);
+	BCD_TO_BIN(day);
+	BCD_TO_BIN(mon);
+	BCD_TO_BIN(year);
+
+	year = year + 1900;
+	if (year < 1970) {
+		year += 100;
+	}
+
+	return mktime(year, mon, day, hour, min, sec);
+}